diff options
Diffstat (limited to 'lib/libsqlite3/src/os_unix.c')
| -rw-r--r-- | lib/libsqlite3/src/os_unix.c | 7569 |
1 files changed, 0 insertions, 7569 deletions
diff --git a/lib/libsqlite3/src/os_unix.c b/lib/libsqlite3/src/os_unix.c deleted file mode 100644 index cc2074eb276..00000000000 --- a/lib/libsqlite3/src/os_unix.c +++ /dev/null @@ -1,7569 +0,0 @@ -/* -** 2004 May 22 -** -** The author disclaims copyright to this source code. In place of -** a legal notice, here is a blessing: -** -** May you do good and not evil. -** May you find forgiveness for yourself and forgive others. -** May you share freely, never taking more than you give. -** -****************************************************************************** -** -** This file contains the VFS implementation for unix-like operating systems -** include Linux, MacOSX, *BSD, QNX, VxWorks, AIX, HPUX, and others. -** -** There are actually several different VFS implementations in this file. -** The differences are in the way that file locking is done. The default -** implementation uses Posix Advisory Locks. Alternative implementations -** use flock(), dot-files, various proprietary locking schemas, or simply -** skip locking all together. -** -** This source file is organized into divisions where the logic for various -** subfunctions is contained within the appropriate division. PLEASE -** KEEP THE STRUCTURE OF THIS FILE INTACT. New code should be placed -** in the correct division and should be clearly labeled. -** -** The layout of divisions is as follows: -** -** * General-purpose declarations and utility functions. -** * Unique file ID logic used by VxWorks. -** * Various locking primitive implementations (all except proxy locking): -** + for Posix Advisory Locks -** + for no-op locks -** + for dot-file locks -** + for flock() locking -** + for named semaphore locks (VxWorks only) -** + for AFP filesystem locks (MacOSX only) -** * sqlite3_file methods not associated with locking. -** * Definitions of sqlite3_io_methods objects for all locking -** methods plus "finder" functions for each locking method. -** * sqlite3_vfs method implementations. -** * Locking primitives for the proxy uber-locking-method. (MacOSX only) -** * Definitions of sqlite3_vfs objects for all locking methods -** plus implementations of sqlite3_os_init() and sqlite3_os_end(). -*/ -#include "sqliteInt.h" -#if SQLITE_OS_UNIX /* This file is used on unix only */ - -/* -** There are various methods for file locking used for concurrency -** control: -** -** 1. POSIX locking (the default), -** 2. No locking, -** 3. Dot-file locking, -** 4. flock() locking, -** 5. AFP locking (OSX only), -** 6. Named POSIX semaphores (VXWorks only), -** 7. proxy locking. (OSX only) -** -** Styles 4, 5, and 7 are only available of SQLITE_ENABLE_LOCKING_STYLE -** is defined to 1. The SQLITE_ENABLE_LOCKING_STYLE also enables automatic -** selection of the appropriate locking style based on the filesystem -** where the database is located. -*/ -#if !defined(SQLITE_ENABLE_LOCKING_STYLE) -# if defined(__APPLE__) -# define SQLITE_ENABLE_LOCKING_STYLE 1 -# else -# define SQLITE_ENABLE_LOCKING_STYLE 0 -# endif -#endif - -/* -** standard include files. -*/ -#include <sys/types.h> -#include <sys/stat.h> -#include <fcntl.h> -#include <unistd.h> -#include <time.h> -#include <sys/time.h> -#include <errno.h> -#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0 -# include <sys/mman.h> -#endif - -#if SQLITE_ENABLE_LOCKING_STYLE -# include <sys/ioctl.h> -# include <sys/file.h> -# include <sys/param.h> -#endif /* SQLITE_ENABLE_LOCKING_STYLE */ - -#if defined(__APPLE__) && ((__MAC_OS_X_VERSION_MIN_REQUIRED > 1050) || \ - (__IPHONE_OS_VERSION_MIN_REQUIRED > 2000)) -# if (!defined(TARGET_OS_EMBEDDED) || (TARGET_OS_EMBEDDED==0)) \ - && (!defined(TARGET_IPHONE_SIMULATOR) || (TARGET_IPHONE_SIMULATOR==0)) -# define HAVE_GETHOSTUUID 1 -# else -# warning "gethostuuid() is disabled." -# endif -#endif - - -#if OS_VXWORKS -# include <sys/ioctl.h> -# include <semaphore.h> -# include <limits.h> -#endif /* OS_VXWORKS */ - -#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE -# include <sys/mount.h> -#endif - -#ifdef HAVE_UTIME -# include <utime.h> -#endif - -/* -** Allowed values of unixFile.fsFlags -*/ -#define SQLITE_FSFLAGS_IS_MSDOS 0x1 - -/* -** If we are to be thread-safe, include the pthreads header and define -** the SQLITE_UNIX_THREADS macro. -*/ -#if SQLITE_THREADSAFE -# include <pthread.h> -# define SQLITE_UNIX_THREADS 1 -#endif - -/* -** Default permissions when creating a new file -*/ -#ifndef SQLITE_DEFAULT_FILE_PERMISSIONS -# define SQLITE_DEFAULT_FILE_PERMISSIONS 0644 -#endif - -/* -** Default permissions when creating auto proxy dir -*/ -#ifndef SQLITE_DEFAULT_PROXYDIR_PERMISSIONS -# define SQLITE_DEFAULT_PROXYDIR_PERMISSIONS 0755 -#endif - -/* -** Maximum supported path-length. -*/ -#define MAX_PATHNAME 512 - -/* Always cast the getpid() return type for compatibility with -** kernel modules in VxWorks. */ -#define osGetpid(X) (pid_t)getpid() - -/* -** Only set the lastErrno if the error code is a real error and not -** a normal expected return code of SQLITE_BUSY or SQLITE_OK -*/ -#define IS_LOCK_ERROR(x) ((x != SQLITE_OK) && (x != SQLITE_BUSY)) - -/* Forward references */ -typedef struct unixShm unixShm; /* Connection shared memory */ -typedef struct unixShmNode unixShmNode; /* Shared memory instance */ -typedef struct unixInodeInfo unixInodeInfo; /* An i-node */ -typedef struct UnixUnusedFd UnixUnusedFd; /* An unused file descriptor */ - -/* -** Sometimes, after a file handle is closed by SQLite, the file descriptor -** cannot be closed immediately. In these cases, instances of the following -** structure are used to store the file descriptor while waiting for an -** opportunity to either close or reuse it. -*/ -struct UnixUnusedFd { - int fd; /* File descriptor to close */ - int flags; /* Flags this file descriptor was opened with */ - UnixUnusedFd *pNext; /* Next unused file descriptor on same file */ -}; - -/* -** The unixFile structure is subclass of sqlite3_file specific to the unix -** VFS implementations. -*/ -typedef struct unixFile unixFile; -struct unixFile { - sqlite3_io_methods const *pMethod; /* Always the first entry */ - sqlite3_vfs *pVfs; /* The VFS that created this unixFile */ - unixInodeInfo *pInode; /* Info about locks on this inode */ - int h; /* The file descriptor */ - unsigned char eFileLock; /* The type of lock held on this fd */ - unsigned short int ctrlFlags; /* Behavioral bits. UNIXFILE_* flags */ - int lastErrno; /* The unix errno from last I/O error */ - void *lockingContext; /* Locking style specific state */ - UnixUnusedFd *pUnused; /* Pre-allocated UnixUnusedFd */ - const char *zPath; /* Name of the file */ - unixShm *pShm; /* Shared memory segment information */ - int szChunk; /* Configured by FCNTL_CHUNK_SIZE */ -#if SQLITE_MAX_MMAP_SIZE>0 - int nFetchOut; /* Number of outstanding xFetch refs */ - sqlite3_int64 mmapSize; /* Usable size of mapping at pMapRegion */ - sqlite3_int64 mmapSizeActual; /* Actual size of mapping at pMapRegion */ - sqlite3_int64 mmapSizeMax; /* Configured FCNTL_MMAP_SIZE value */ - void *pMapRegion; /* Memory mapped region */ -#endif -#ifdef __QNXNTO__ - int sectorSize; /* Device sector size */ - int deviceCharacteristics; /* Precomputed device characteristics */ -#endif -#if SQLITE_ENABLE_LOCKING_STYLE - int openFlags; /* The flags specified at open() */ -#endif -#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__) - unsigned fsFlags; /* cached details from statfs() */ -#endif -#if OS_VXWORKS - struct vxworksFileId *pId; /* Unique file ID */ -#endif -#ifdef SQLITE_DEBUG - /* The next group of variables are used to track whether or not the - ** transaction counter in bytes 24-27 of database files are updated - ** whenever any part of the database changes. An assertion fault will - ** occur if a file is updated without also updating the transaction - ** counter. This test is made to avoid new problems similar to the - ** one described by ticket #3584. - */ - unsigned char transCntrChng; /* True if the transaction counter changed */ - unsigned char dbUpdate; /* True if any part of database file changed */ - unsigned char inNormalWrite; /* True if in a normal write operation */ - -#endif - -#ifdef SQLITE_TEST - /* In test mode, increase the size of this structure a bit so that - ** it is larger than the struct CrashFile defined in test6.c. - */ - char aPadding[32]; -#endif -}; - -/* This variable holds the process id (pid) from when the xRandomness() -** method was called. If xOpen() is called from a different process id, -** indicating that a fork() has occurred, the PRNG will be reset. -*/ -static pid_t randomnessPid = 0; - -/* -** Allowed values for the unixFile.ctrlFlags bitmask: -*/ -#define UNIXFILE_EXCL 0x01 /* Connections from one process only */ -#define UNIXFILE_RDONLY 0x02 /* Connection is read only */ -#define UNIXFILE_PERSIST_WAL 0x04 /* Persistent WAL mode */ -#ifndef SQLITE_DISABLE_DIRSYNC -# define UNIXFILE_DIRSYNC 0x08 /* Directory sync needed */ -#else -# define UNIXFILE_DIRSYNC 0x00 -#endif -#define UNIXFILE_PSOW 0x10 /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */ -#define UNIXFILE_DELETE 0x20 /* Delete on close */ -#define UNIXFILE_URI 0x40 /* Filename might have query parameters */ -#define UNIXFILE_NOLOCK 0x80 /* Do no file locking */ -#define UNIXFILE_WARNED 0x0100 /* verifyDbFile() warnings issued */ -#define UNIXFILE_BLOCK 0x0200 /* Next SHM lock might block */ - -/* -** Include code that is common to all os_*.c files -*/ -#include "os_common.h" - -/* -** Define various macros that are missing from some systems. -*/ -#ifndef O_LARGEFILE -# define O_LARGEFILE 0 -#endif -#ifdef SQLITE_DISABLE_LFS -# undef O_LARGEFILE -# define O_LARGEFILE 0 -#endif -#ifndef O_NOFOLLOW -# define O_NOFOLLOW 0 -#endif -#ifndef O_BINARY -# define O_BINARY 0 -#endif - -/* -** The threadid macro resolves to the thread-id or to 0. Used for -** testing and debugging only. -*/ -#if SQLITE_THREADSAFE -#define threadid pthread_self() -#else -#define threadid 0 -#endif - -/* -** HAVE_MREMAP defaults to true on Linux and false everywhere else. -*/ -#if !defined(HAVE_MREMAP) -# if defined(__linux__) && defined(_GNU_SOURCE) -# define HAVE_MREMAP 1 -# else -# define HAVE_MREMAP 0 -# endif -#endif - -/* -** Explicitly call the 64-bit version of lseek() on Android. Otherwise, lseek() -** is the 32-bit version, even if _FILE_OFFSET_BITS=64 is defined. -*/ -#ifdef __ANDROID__ -# define lseek lseek64 -#endif - -/* -** Different Unix systems declare open() in different ways. Same use -** open(const char*,int,mode_t). Others use open(const char*,int,...). -** The difference is important when using a pointer to the function. -** -** The safest way to deal with the problem is to always use this wrapper -** which always has the same well-defined interface. -*/ -static int posixOpen(const char *zFile, int flags, int mode){ - return open(zFile, flags, mode); -} - -/* -** On some systems, calls to fchown() will trigger a message in a security -** log if they come from non-root processes. So avoid calling fchown() if -** we are not running as root. -*/ -static int posixFchown(int fd, uid_t uid, gid_t gid){ -#if OS_VXWORKS - return 0; -#else - return geteuid() ? 0 : fchown(fd,uid,gid); -#endif -} - -/* Forward reference */ -static int openDirectory(const char*, int*); -static int unixGetpagesize(void); - -/* -** Many system calls are accessed through pointer-to-functions so that -** they may be overridden at runtime to facilitate fault injection during -** testing and sandboxing. The following array holds the names and pointers -** to all overrideable system calls. -*/ -static struct unix_syscall { - const char *zName; /* Name of the system call */ - sqlite3_syscall_ptr pCurrent; /* Current value of the system call */ - sqlite3_syscall_ptr pDefault; /* Default value */ -} aSyscall[] = { - { "open", (sqlite3_syscall_ptr)posixOpen, 0 }, -#define osOpen ((int(*)(const char*,int,int))aSyscall[0].pCurrent) - - { "close", (sqlite3_syscall_ptr)close, 0 }, -#define osClose ((int(*)(int))aSyscall[1].pCurrent) - - { "access", (sqlite3_syscall_ptr)access, 0 }, -#define osAccess ((int(*)(const char*,int))aSyscall[2].pCurrent) - - { "getcwd", (sqlite3_syscall_ptr)getcwd, 0 }, -#define osGetcwd ((char*(*)(char*,size_t))aSyscall[3].pCurrent) - - { "stat", (sqlite3_syscall_ptr)stat, 0 }, -#define osStat ((int(*)(const char*,struct stat*))aSyscall[4].pCurrent) - -/* -** The DJGPP compiler environment looks mostly like Unix, but it -** lacks the fcntl() system call. So redefine fcntl() to be something -** that always succeeds. This means that locking does not occur under -** DJGPP. But it is DOS - what did you expect? -*/ -#ifdef __DJGPP__ - { "fstat", 0, 0 }, -#define osFstat(a,b,c) 0 -#else - { "fstat", (sqlite3_syscall_ptr)fstat, 0 }, -#define osFstat ((int(*)(int,struct stat*))aSyscall[5].pCurrent) -#endif - - { "ftruncate", (sqlite3_syscall_ptr)ftruncate, 0 }, -#define osFtruncate ((int(*)(int,off_t))aSyscall[6].pCurrent) - - { "fcntl", (sqlite3_syscall_ptr)fcntl, 0 }, -#define osFcntl ((int(*)(int,int,...))aSyscall[7].pCurrent) - - { "read", (sqlite3_syscall_ptr)read, 0 }, -#define osRead ((ssize_t(*)(int,void*,size_t))aSyscall[8].pCurrent) - -#if defined(USE_PREAD) || SQLITE_ENABLE_LOCKING_STYLE - { "pread", (sqlite3_syscall_ptr)pread, 0 }, -#else - { "pread", (sqlite3_syscall_ptr)0, 0 }, -#endif -#define osPread ((ssize_t(*)(int,void*,size_t,off_t))aSyscall[9].pCurrent) - -#if defined(USE_PREAD64) - { "pread64", (sqlite3_syscall_ptr)pread64, 0 }, -#else - { "pread64", (sqlite3_syscall_ptr)0, 0 }, -#endif -#define osPread64 ((ssize_t(*)(int,void*,size_t,off_t))aSyscall[10].pCurrent) - - { "write", (sqlite3_syscall_ptr)write, 0 }, -#define osWrite ((ssize_t(*)(int,const void*,size_t))aSyscall[11].pCurrent) - -#if defined(USE_PREAD) || SQLITE_ENABLE_LOCKING_STYLE - { "pwrite", (sqlite3_syscall_ptr)pwrite, 0 }, -#else - { "pwrite", (sqlite3_syscall_ptr)0, 0 }, -#endif -#define osPwrite ((ssize_t(*)(int,const void*,size_t,off_t))\ - aSyscall[12].pCurrent) - -#if defined(USE_PREAD64) - { "pwrite64", (sqlite3_syscall_ptr)pwrite64, 0 }, -#else - { "pwrite64", (sqlite3_syscall_ptr)0, 0 }, -#endif -#define osPwrite64 ((ssize_t(*)(int,const void*,size_t,off_t))\ - aSyscall[13].pCurrent) - - { "fchmod", (sqlite3_syscall_ptr)fchmod, 0 }, -#define osFchmod ((int(*)(int,mode_t))aSyscall[14].pCurrent) - -#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE - { "fallocate", (sqlite3_syscall_ptr)posix_fallocate, 0 }, -#else - { "fallocate", (sqlite3_syscall_ptr)0, 0 }, -#endif -#define osFallocate ((int(*)(int,off_t,off_t))aSyscall[15].pCurrent) - - { "unlink", (sqlite3_syscall_ptr)unlink, 0 }, -#define osUnlink ((int(*)(const char*))aSyscall[16].pCurrent) - - { "openDirectory", (sqlite3_syscall_ptr)openDirectory, 0 }, -#define osOpenDirectory ((int(*)(const char*,int*))aSyscall[17].pCurrent) - - { "mkdir", (sqlite3_syscall_ptr)mkdir, 0 }, -#define osMkdir ((int(*)(const char*,mode_t))aSyscall[18].pCurrent) - - { "rmdir", (sqlite3_syscall_ptr)rmdir, 0 }, -#define osRmdir ((int(*)(const char*))aSyscall[19].pCurrent) - - { "fchown", (sqlite3_syscall_ptr)posixFchown, 0 }, -#define osFchown ((int(*)(int,uid_t,gid_t))aSyscall[20].pCurrent) - -#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0 - { "mmap", (sqlite3_syscall_ptr)mmap, 0 }, -#define osMmap ((void*(*)(void*,size_t,int,int,int,off_t))aSyscall[21].pCurrent) - - { "munmap", (sqlite3_syscall_ptr)munmap, 0 }, -#define osMunmap ((void*(*)(void*,size_t))aSyscall[22].pCurrent) - -#if HAVE_MREMAP - { "mremap", (sqlite3_syscall_ptr)mremap, 0 }, -#else - { "mremap", (sqlite3_syscall_ptr)0, 0 }, -#endif -#define osMremap ((void*(*)(void*,size_t,size_t,int,...))aSyscall[23].pCurrent) - { "getpagesize", (sqlite3_syscall_ptr)unixGetpagesize, 0 }, -#define osGetpagesize ((int(*)(void))aSyscall[24].pCurrent) - -#endif - -}; /* End of the overrideable system calls */ - -/* -** This is the xSetSystemCall() method of sqlite3_vfs for all of the -** "unix" VFSes. Return SQLITE_OK opon successfully updating the -** system call pointer, or SQLITE_NOTFOUND if there is no configurable -** system call named zName. -*/ -static int unixSetSystemCall( - sqlite3_vfs *pNotUsed, /* The VFS pointer. Not used */ - const char *zName, /* Name of system call to override */ - sqlite3_syscall_ptr pNewFunc /* Pointer to new system call value */ -){ - unsigned int i; - int rc = SQLITE_NOTFOUND; - - UNUSED_PARAMETER(pNotUsed); - if( zName==0 ){ - /* If no zName is given, restore all system calls to their default - ** settings and return NULL - */ - rc = SQLITE_OK; - for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){ - if( aSyscall[i].pDefault ){ - aSyscall[i].pCurrent = aSyscall[i].pDefault; - } - } - }else{ - /* If zName is specified, operate on only the one system call - ** specified. - */ - for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){ - if( strcmp(zName, aSyscall[i].zName)==0 ){ - if( aSyscall[i].pDefault==0 ){ - aSyscall[i].pDefault = aSyscall[i].pCurrent; - } - rc = SQLITE_OK; - if( pNewFunc==0 ) pNewFunc = aSyscall[i].pDefault; - aSyscall[i].pCurrent = pNewFunc; - break; - } - } - } - return rc; -} - -/* -** Return the value of a system call. Return NULL if zName is not a -** recognized system call name. NULL is also returned if the system call -** is currently undefined. -*/ -static sqlite3_syscall_ptr unixGetSystemCall( - sqlite3_vfs *pNotUsed, - const char *zName -){ - unsigned int i; - - UNUSED_PARAMETER(pNotUsed); - for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){ - if( strcmp(zName, aSyscall[i].zName)==0 ) return aSyscall[i].pCurrent; - } - return 0; -} - -/* -** Return the name of the first system call after zName. If zName==NULL -** then return the name of the first system call. Return NULL if zName -** is the last system call or if zName is not the name of a valid -** system call. -*/ -static const char *unixNextSystemCall(sqlite3_vfs *p, const char *zName){ - int i = -1; - - UNUSED_PARAMETER(p); - if( zName ){ - for(i=0; i<ArraySize(aSyscall)-1; i++){ - if( strcmp(zName, aSyscall[i].zName)==0 ) break; - } - } - for(i++; i<ArraySize(aSyscall); i++){ - if( aSyscall[i].pCurrent!=0 ) return aSyscall[i].zName; - } - return 0; -} - -/* -** Do not accept any file descriptor less than this value, in order to avoid -** opening database file using file descriptors that are commonly used for -** standard input, output, and error. -*/ -#ifndef SQLITE_MINIMUM_FILE_DESCRIPTOR -# define SQLITE_MINIMUM_FILE_DESCRIPTOR 3 -#endif - -/* -** Invoke open(). Do so multiple times, until it either succeeds or -** fails for some reason other than EINTR. -** -** If the file creation mode "m" is 0 then set it to the default for -** SQLite. The default is SQLITE_DEFAULT_FILE_PERMISSIONS (normally -** 0644) as modified by the system umask. If m is not 0, then -** make the file creation mode be exactly m ignoring the umask. -** -** The m parameter will be non-zero only when creating -wal, -journal, -** and -shm files. We want those files to have *exactly* the same -** permissions as their original database, unadulterated by the umask. -** In that way, if a database file is -rw-rw-rw or -rw-rw-r-, and a -** transaction crashes and leaves behind hot journals, then any -** process that is able to write to the database will also be able to -** recover the hot journals. -*/ -static int robust_open(const char *z, int f, mode_t m){ - int fd; - mode_t m2 = m ? m : SQLITE_DEFAULT_FILE_PERMISSIONS; - while(1){ -#if defined(O_CLOEXEC) - fd = osOpen(z,f|O_CLOEXEC,m2); -#else - fd = osOpen(z,f,m2); -#endif - if( fd<0 ){ - if( errno==EINTR ) continue; - break; - } - if( fd>=SQLITE_MINIMUM_FILE_DESCRIPTOR ) break; - osClose(fd); - sqlite3_log(SQLITE_WARNING, - "attempt to open \"%s\" as file descriptor %d", z, fd); - fd = -1; - if( osOpen("/dev/null", f, m)<0 ) break; - } - if( fd>=0 ){ - if( m!=0 ){ - struct stat statbuf; - if( osFstat(fd, &statbuf)==0 - && statbuf.st_size==0 - && (statbuf.st_mode&0777)!=m - ){ - osFchmod(fd, m); - } - } -#if defined(FD_CLOEXEC) && (!defined(O_CLOEXEC) || O_CLOEXEC==0) - osFcntl(fd, F_SETFD, osFcntl(fd, F_GETFD, 0) | FD_CLOEXEC); -#endif - } - return fd; -} - -/* -** Helper functions to obtain and relinquish the global mutex. The -** global mutex is used to protect the unixInodeInfo and -** vxworksFileId objects used by this file, all of which may be -** shared by multiple threads. -** -** Function unixMutexHeld() is used to assert() that the global mutex -** is held when required. This function is only used as part of assert() -** statements. e.g. -** -** unixEnterMutex() -** assert( unixMutexHeld() ); -** unixEnterLeave() -*/ -static void unixEnterMutex(void){ - sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1)); -} -static void unixLeaveMutex(void){ - sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1)); -} -#ifdef SQLITE_DEBUG -static int unixMutexHeld(void) { - return sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1)); -} -#endif - - -#ifdef SQLITE_HAVE_OS_TRACE -/* -** Helper function for printing out trace information from debugging -** binaries. This returns the string representation of the supplied -** integer lock-type. -*/ -static const char *azFileLock(int eFileLock){ - switch( eFileLock ){ - case NO_LOCK: return "NONE"; - case SHARED_LOCK: return "SHARED"; - case RESERVED_LOCK: return "RESERVED"; - case PENDING_LOCK: return "PENDING"; - case EXCLUSIVE_LOCK: return "EXCLUSIVE"; - } - return "ERROR"; -} -#endif - -#ifdef SQLITE_LOCK_TRACE -/* -** Print out information about all locking operations. -** -** This routine is used for troubleshooting locks on multithreaded -** platforms. Enable by compiling with the -DSQLITE_LOCK_TRACE -** command-line option on the compiler. This code is normally -** turned off. -*/ -static int lockTrace(int fd, int op, struct flock *p){ - char *zOpName, *zType; - int s; - int savedErrno; - if( op==F_GETLK ){ - zOpName = "GETLK"; - }else if( op==F_SETLK ){ - zOpName = "SETLK"; - }else{ - s = osFcntl(fd, op, p); - sqlite3DebugPrintf("fcntl unknown %d %d %d\n", fd, op, s); - return s; - } - if( p->l_type==F_RDLCK ){ - zType = "RDLCK"; - }else if( p->l_type==F_WRLCK ){ - zType = "WRLCK"; - }else if( p->l_type==F_UNLCK ){ - zType = "UNLCK"; - }else{ - assert( 0 ); - } - assert( p->l_whence==SEEK_SET ); - s = osFcntl(fd, op, p); - savedErrno = errno; - sqlite3DebugPrintf("fcntl %d %d %s %s %d %d %d %d\n", - threadid, fd, zOpName, zType, (int)p->l_start, (int)p->l_len, - (int)p->l_pid, s); - if( s==(-1) && op==F_SETLK && (p->l_type==F_RDLCK || p->l_type==F_WRLCK) ){ - struct flock l2; - l2 = *p; - osFcntl(fd, F_GETLK, &l2); - if( l2.l_type==F_RDLCK ){ - zType = "RDLCK"; - }else if( l2.l_type==F_WRLCK ){ - zType = "WRLCK"; - }else if( l2.l_type==F_UNLCK ){ - zType = "UNLCK"; - }else{ - assert( 0 ); - } - sqlite3DebugPrintf("fcntl-failure-reason: %s %d %d %d\n", - zType, (int)l2.l_start, (int)l2.l_len, (int)l2.l_pid); - } - errno = savedErrno; - return s; -} -#undef osFcntl -#define osFcntl lockTrace -#endif /* SQLITE_LOCK_TRACE */ - -/* -** Retry ftruncate() calls that fail due to EINTR -** -** All calls to ftruncate() within this file should be made through -** this wrapper. On the Android platform, bypassing the logic below -** could lead to a corrupt database. -*/ -static int robust_ftruncate(int h, sqlite3_int64 sz){ - int rc; -#ifdef __ANDROID__ - /* On Android, ftruncate() always uses 32-bit offsets, even if - ** _FILE_OFFSET_BITS=64 is defined. This means it is unsafe to attempt to - ** truncate a file to any size larger than 2GiB. Silently ignore any - ** such attempts. */ - if( sz>(sqlite3_int64)0x7FFFFFFF ){ - rc = SQLITE_OK; - }else -#endif - do{ rc = osFtruncate(h,sz); }while( rc<0 && errno==EINTR ); - return rc; -} - -/* -** This routine translates a standard POSIX errno code into something -** useful to the clients of the sqlite3 functions. Specifically, it is -** intended to translate a variety of "try again" errors into SQLITE_BUSY -** and a variety of "please close the file descriptor NOW" errors into -** SQLITE_IOERR -** -** Errors during initialization of locks, or file system support for locks, -** should handle ENOLCK, ENOTSUP, EOPNOTSUPP separately. -*/ -static int sqliteErrorFromPosixError(int posixError, int sqliteIOErr) { - switch (posixError) { -#if 0 - /* At one point this code was not commented out. In theory, this branch - ** should never be hit, as this function should only be called after - ** a locking-related function (i.e. fcntl()) has returned non-zero with - ** the value of errno as the first argument. Since a system call has failed, - ** errno should be non-zero. - ** - ** Despite this, if errno really is zero, we still don't want to return - ** SQLITE_OK. The system call failed, and *some* SQLite error should be - ** propagated back to the caller. Commenting this branch out means errno==0 - ** will be handled by the "default:" case below. - */ - case 0: - return SQLITE_OK; -#endif - - case EAGAIN: - case ETIMEDOUT: - case EBUSY: - case EINTR: - case ENOLCK: - /* random NFS retry error, unless during file system support - * introspection, in which it actually means what it says */ - return SQLITE_BUSY; - - case EACCES: - /* EACCES is like EAGAIN during locking operations, but not any other time*/ - if( (sqliteIOErr == SQLITE_IOERR_LOCK) || - (sqliteIOErr == SQLITE_IOERR_UNLOCK) || - (sqliteIOErr == SQLITE_IOERR_RDLOCK) || - (sqliteIOErr == SQLITE_IOERR_CHECKRESERVEDLOCK) ){ - return SQLITE_BUSY; - } - /* else fall through */ - case EPERM: - return SQLITE_PERM; - -#if EOPNOTSUPP!=ENOTSUP - case EOPNOTSUPP: - /* something went terribly awry, unless during file system support - * introspection, in which it actually means what it says */ -#endif -#ifdef ENOTSUP - case ENOTSUP: - /* invalid fd, unless during file system support introspection, in which - * it actually means what it says */ -#endif - case EIO: - case EBADF: - case EINVAL: - case ENOTCONN: - case ENODEV: - case ENXIO: - case ENOENT: -#ifdef ESTALE /* ESTALE is not defined on Interix systems */ - case ESTALE: -#endif - case ENOSYS: - /* these should force the client to close the file and reconnect */ - - default: - return sqliteIOErr; - } -} - - -/****************************************************************************** -****************** Begin Unique File ID Utility Used By VxWorks *************** -** -** On most versions of unix, we can get a unique ID for a file by concatenating -** the device number and the inode number. But this does not work on VxWorks. -** On VxWorks, a unique file id must be based on the canonical filename. -** -** A pointer to an instance of the following structure can be used as a -** unique file ID in VxWorks. Each instance of this structure contains -** a copy of the canonical filename. There is also a reference count. -** The structure is reclaimed when the number of pointers to it drops to -** zero. -** -** There are never very many files open at one time and lookups are not -** a performance-critical path, so it is sufficient to put these -** structures on a linked list. -*/ -struct vxworksFileId { - struct vxworksFileId *pNext; /* Next in a list of them all */ - int nRef; /* Number of references to this one */ - int nName; /* Length of the zCanonicalName[] string */ - char *zCanonicalName; /* Canonical filename */ -}; - -#if OS_VXWORKS -/* -** All unique filenames are held on a linked list headed by this -** variable: -*/ -static struct vxworksFileId *vxworksFileList = 0; - -/* -** Simplify a filename into its canonical form -** by making the following changes: -** -** * removing any trailing and duplicate / -** * convert /./ into just / -** * convert /A/../ where A is any simple name into just / -** -** Changes are made in-place. Return the new name length. -** -** The original filename is in z[0..n-1]. Return the number of -** characters in the simplified name. -*/ -static int vxworksSimplifyName(char *z, int n){ - int i, j; - while( n>1 && z[n-1]=='/' ){ n--; } - for(i=j=0; i<n; i++){ - if( z[i]=='/' ){ - if( z[i+1]=='/' ) continue; - if( z[i+1]=='.' && i+2<n && z[i+2]=='/' ){ - i += 1; - continue; - } - if( z[i+1]=='.' && i+3<n && z[i+2]=='.' && z[i+3]=='/' ){ - while( j>0 && z[j-1]!='/' ){ j--; } - if( j>0 ){ j--; } - i += 2; - continue; - } - } - z[j++] = z[i]; - } - z[j] = 0; - return j; -} - -/* -** Find a unique file ID for the given absolute pathname. Return -** a pointer to the vxworksFileId object. This pointer is the unique -** file ID. -** -** The nRef field of the vxworksFileId object is incremented before -** the object is returned. A new vxworksFileId object is created -** and added to the global list if necessary. -** -** If a memory allocation error occurs, return NULL. -*/ -static struct vxworksFileId *vxworksFindFileId(const char *zAbsoluteName){ - struct vxworksFileId *pNew; /* search key and new file ID */ - struct vxworksFileId *pCandidate; /* For looping over existing file IDs */ - int n; /* Length of zAbsoluteName string */ - - assert( zAbsoluteName[0]=='/' ); - n = (int)strlen(zAbsoluteName); - pNew = sqlite3_malloc64( sizeof(*pNew) + (n+1) ); - if( pNew==0 ) return 0; - pNew->zCanonicalName = (char*)&pNew[1]; - memcpy(pNew->zCanonicalName, zAbsoluteName, n+1); - n = vxworksSimplifyName(pNew->zCanonicalName, n); - - /* Search for an existing entry that matching the canonical name. - ** If found, increment the reference count and return a pointer to - ** the existing file ID. - */ - unixEnterMutex(); - for(pCandidate=vxworksFileList; pCandidate; pCandidate=pCandidate->pNext){ - if( pCandidate->nName==n - && memcmp(pCandidate->zCanonicalName, pNew->zCanonicalName, n)==0 - ){ - sqlite3_free(pNew); - pCandidate->nRef++; - unixLeaveMutex(); - return pCandidate; - } - } - - /* No match was found. We will make a new file ID */ - pNew->nRef = 1; - pNew->nName = n; - pNew->pNext = vxworksFileList; - vxworksFileList = pNew; - unixLeaveMutex(); - return pNew; -} - -/* -** Decrement the reference count on a vxworksFileId object. Free -** the object when the reference count reaches zero. -*/ -static void vxworksReleaseFileId(struct vxworksFileId *pId){ - unixEnterMutex(); - assert( pId->nRef>0 ); - pId->nRef--; - if( pId->nRef==0 ){ - struct vxworksFileId **pp; - for(pp=&vxworksFileList; *pp && *pp!=pId; pp = &((*pp)->pNext)){} - assert( *pp==pId ); - *pp = pId->pNext; - sqlite3_free(pId); - } - unixLeaveMutex(); -} -#endif /* OS_VXWORKS */ -/*************** End of Unique File ID Utility Used By VxWorks **************** -******************************************************************************/ - - -/****************************************************************************** -*************************** Posix Advisory Locking **************************** -** -** POSIX advisory locks are broken by design. ANSI STD 1003.1 (1996) -** section 6.5.2.2 lines 483 through 490 specify that when a process -** sets or clears a lock, that operation overrides any prior locks set -** by the same process. It does not explicitly say so, but this implies -** that it overrides locks set by the same process using a different -** file descriptor. Consider this test case: -** -** int fd1 = open("./file1", O_RDWR|O_CREAT, 0644); -** int fd2 = open("./file2", O_RDWR|O_CREAT, 0644); -** -** Suppose ./file1 and ./file2 are really the same file (because -** one is a hard or symbolic link to the other) then if you set -** an exclusive lock on fd1, then try to get an exclusive lock -** on fd2, it works. I would have expected the second lock to -** fail since there was already a lock on the file due to fd1. -** But not so. Since both locks came from the same process, the -** second overrides the first, even though they were on different -** file descriptors opened on different file names. -** -** This means that we cannot use POSIX locks to synchronize file access -** among competing threads of the same process. POSIX locks will work fine -** to synchronize access for threads in separate processes, but not -** threads within the same process. -** -** To work around the problem, SQLite has to manage file locks internally -** on its own. Whenever a new database is opened, we have to find the -** specific inode of the database file (the inode is determined by the -** st_dev and st_ino fields of the stat structure that fstat() fills in) -** and check for locks already existing on that inode. When locks are -** created or removed, we have to look at our own internal record of the -** locks to see if another thread has previously set a lock on that same -** inode. -** -** (Aside: The use of inode numbers as unique IDs does not work on VxWorks. -** For VxWorks, we have to use the alternative unique ID system based on -** canonical filename and implemented in the previous division.) -** -** The sqlite3_file structure for POSIX is no longer just an integer file -** descriptor. It is now a structure that holds the integer file -** descriptor and a pointer to a structure that describes the internal -** locks on the corresponding inode. There is one locking structure -** per inode, so if the same inode is opened twice, both unixFile structures -** point to the same locking structure. The locking structure keeps -** a reference count (so we will know when to delete it) and a "cnt" -** field that tells us its internal lock status. cnt==0 means the -** file is unlocked. cnt==-1 means the file has an exclusive lock. -** cnt>0 means there are cnt shared locks on the file. -** -** Any attempt to lock or unlock a file first checks the locking -** structure. The fcntl() system call is only invoked to set a -** POSIX lock if the internal lock structure transitions between -** a locked and an unlocked state. -** -** But wait: there are yet more problems with POSIX advisory locks. -** -** If you close a file descriptor that points to a file that has locks, -** all locks on that file that are owned by the current process are -** released. To work around this problem, each unixInodeInfo object -** maintains a count of the number of pending locks on tha inode. -** When an attempt is made to close an unixFile, if there are -** other unixFile open on the same inode that are holding locks, the call -** to close() the file descriptor is deferred until all of the locks clear. -** The unixInodeInfo structure keeps a list of file descriptors that need to -** be closed and that list is walked (and cleared) when the last lock -** clears. -** -** Yet another problem: LinuxThreads do not play well with posix locks. -** -** Many older versions of linux use the LinuxThreads library which is -** not posix compliant. Under LinuxThreads, a lock created by thread -** A cannot be modified or overridden by a different thread B. -** Only thread A can modify the lock. Locking behavior is correct -** if the appliation uses the newer Native Posix Thread Library (NPTL) -** on linux - with NPTL a lock created by thread A can override locks -** in thread B. But there is no way to know at compile-time which -** threading library is being used. So there is no way to know at -** compile-time whether or not thread A can override locks on thread B. -** One has to do a run-time check to discover the behavior of the -** current process. -** -** SQLite used to support LinuxThreads. But support for LinuxThreads -** was dropped beginning with version 3.7.0. SQLite will still work with -** LinuxThreads provided that (1) there is no more than one connection -** per database file in the same process and (2) database connections -** do not move across threads. -*/ - -/* -** An instance of the following structure serves as the key used -** to locate a particular unixInodeInfo object. -*/ -struct unixFileId { - dev_t dev; /* Device number */ -#if OS_VXWORKS - struct vxworksFileId *pId; /* Unique file ID for vxworks. */ -#else - ino_t ino; /* Inode number */ -#endif -}; - -/* -** An instance of the following structure is allocated for each open -** inode. Or, on LinuxThreads, there is one of these structures for -** each inode opened by each thread. -** -** A single inode can have multiple file descriptors, so each unixFile -** structure contains a pointer to an instance of this object and this -** object keeps a count of the number of unixFile pointing to it. -*/ -struct unixInodeInfo { - struct unixFileId fileId; /* The lookup key */ - int nShared; /* Number of SHARED locks held */ - unsigned char eFileLock; /* One of SHARED_LOCK, RESERVED_LOCK etc. */ - unsigned char bProcessLock; /* An exclusive process lock is held */ - int nRef; /* Number of pointers to this structure */ - unixShmNode *pShmNode; /* Shared memory associated with this inode */ - int nLock; /* Number of outstanding file locks */ - UnixUnusedFd *pUnused; /* Unused file descriptors to close */ - unixInodeInfo *pNext; /* List of all unixInodeInfo objects */ - unixInodeInfo *pPrev; /* .... doubly linked */ -#if SQLITE_ENABLE_LOCKING_STYLE - unsigned long long sharedByte; /* for AFP simulated shared lock */ -#endif -#if OS_VXWORKS - sem_t *pSem; /* Named POSIX semaphore */ - char aSemName[MAX_PATHNAME+2]; /* Name of that semaphore */ -#endif -}; - -/* -** A lists of all unixInodeInfo objects. -*/ -static unixInodeInfo *inodeList = 0; - -/* -** -** This function - unixLogError_x(), is only ever called via the macro -** unixLogError(). -** -** It is invoked after an error occurs in an OS function and errno has been -** set. It logs a message using sqlite3_log() containing the current value of -** errno and, if possible, the human-readable equivalent from strerror() or -** strerror_r(). -** -** The first argument passed to the macro should be the error code that -** will be returned to SQLite (e.g. SQLITE_IOERR_DELETE, SQLITE_CANTOPEN). -** The two subsequent arguments should be the name of the OS function that -** failed (e.g. "unlink", "open") and the associated file-system path, -** if any. -*/ -#define unixLogError(a,b,c) unixLogErrorAtLine(a,b,c,__LINE__) -static int unixLogErrorAtLine( - int errcode, /* SQLite error code */ - const char *zFunc, /* Name of OS function that failed */ - const char *zPath, /* File path associated with error */ - int iLine /* Source line number where error occurred */ -){ - char *zErr; /* Message from strerror() or equivalent */ - int iErrno = errno; /* Saved syscall error number */ - - /* If this is not a threadsafe build (SQLITE_THREADSAFE==0), then use - ** the strerror() function to obtain the human-readable error message - ** equivalent to errno. Otherwise, use strerror_r(). - */ -#if SQLITE_THREADSAFE && defined(HAVE_STRERROR_R) - char aErr[80]; - memset(aErr, 0, sizeof(aErr)); - zErr = aErr; - - /* If STRERROR_R_CHAR_P (set by autoconf scripts) or __USE_GNU is defined, - ** assume that the system provides the GNU version of strerror_r() that - ** returns a pointer to a buffer containing the error message. That pointer - ** may point to aErr[], or it may point to some static storage somewhere. - ** Otherwise, assume that the system provides the POSIX version of - ** strerror_r(), which always writes an error message into aErr[]. - ** - ** If the code incorrectly assumes that it is the POSIX version that is - ** available, the error message will often be an empty string. Not a - ** huge problem. Incorrectly concluding that the GNU version is available - ** could lead to a segfault though. - */ -#if defined(STRERROR_R_CHAR_P) || defined(__USE_GNU) - zErr = -# endif - strerror_r(iErrno, aErr, sizeof(aErr)-1); - -#elif SQLITE_THREADSAFE - /* This is a threadsafe build, but strerror_r() is not available. */ - zErr = ""; -#else - /* Non-threadsafe build, use strerror(). */ - zErr = strerror(iErrno); -#endif - - if( zPath==0 ) zPath = ""; - sqlite3_log(errcode, - "os_unix.c:%d: (%d) %s(%s) - %s", - iLine, iErrno, zFunc, zPath, zErr - ); - - return errcode; -} - -/* -** Close a file descriptor. -** -** We assume that close() almost always works, since it is only in a -** very sick application or on a very sick platform that it might fail. -** If it does fail, simply leak the file descriptor, but do log the -** error. -** -** Note that it is not safe to retry close() after EINTR since the -** file descriptor might have already been reused by another thread. -** So we don't even try to recover from an EINTR. Just log the error -** and move on. -*/ -static void robust_close(unixFile *pFile, int h, int lineno){ - if( osClose(h) ){ - unixLogErrorAtLine(SQLITE_IOERR_CLOSE, "close", - pFile ? pFile->zPath : 0, lineno); - } -} - -/* -** Set the pFile->lastErrno. Do this in a subroutine as that provides -** a convenient place to set a breakpoint. -*/ -static void storeLastErrno(unixFile *pFile, int error){ - pFile->lastErrno = error; -} - -/* -** Close all file descriptors accumuated in the unixInodeInfo->pUnused list. -*/ -static void closePendingFds(unixFile *pFile){ - unixInodeInfo *pInode = pFile->pInode; - UnixUnusedFd *p; - UnixUnusedFd *pNext; - for(p=pInode->pUnused; p; p=pNext){ - pNext = p->pNext; - robust_close(pFile, p->fd, __LINE__); - sqlite3_free(p); - } - pInode->pUnused = 0; -} - -/* -** Release a unixInodeInfo structure previously allocated by findInodeInfo(). -** -** The mutex entered using the unixEnterMutex() function must be held -** when this function is called. -*/ -static void releaseInodeInfo(unixFile *pFile){ - unixInodeInfo *pInode = pFile->pInode; - assert( unixMutexHeld() ); - if( ALWAYS(pInode) ){ - pInode->nRef--; - if( pInode->nRef==0 ){ - assert( pInode->pShmNode==0 ); - closePendingFds(pFile); - if( pInode->pPrev ){ - assert( pInode->pPrev->pNext==pInode ); - pInode->pPrev->pNext = pInode->pNext; - }else{ - assert( inodeList==pInode ); - inodeList = pInode->pNext; - } - if( pInode->pNext ){ - assert( pInode->pNext->pPrev==pInode ); - pInode->pNext->pPrev = pInode->pPrev; - } - sqlite3_free(pInode); - } - } -} - -/* -** Given a file descriptor, locate the unixInodeInfo object that -** describes that file descriptor. Create a new one if necessary. The -** return value might be uninitialized if an error occurs. -** -** The mutex entered using the unixEnterMutex() function must be held -** when this function is called. -** -** Return an appropriate error code. -*/ -static int findInodeInfo( - unixFile *pFile, /* Unix file with file desc used in the key */ - unixInodeInfo **ppInode /* Return the unixInodeInfo object here */ -){ - int rc; /* System call return code */ - int fd; /* The file descriptor for pFile */ - struct unixFileId fileId; /* Lookup key for the unixInodeInfo */ - struct stat statbuf; /* Low-level file information */ - unixInodeInfo *pInode = 0; /* Candidate unixInodeInfo object */ - - assert( unixMutexHeld() ); - - /* Get low-level information about the file that we can used to - ** create a unique name for the file. - */ - fd = pFile->h; - rc = osFstat(fd, &statbuf); - if( rc!=0 ){ - storeLastErrno(pFile, errno); -#ifdef EOVERFLOW - if( pFile->lastErrno==EOVERFLOW ) return SQLITE_NOLFS; -#endif - return SQLITE_IOERR; - } - -#ifdef __APPLE__ - /* On OS X on an msdos filesystem, the inode number is reported - ** incorrectly for zero-size files. See ticket #3260. To work - ** around this problem (we consider it a bug in OS X, not SQLite) - ** we always increase the file size to 1 by writing a single byte - ** prior to accessing the inode number. The one byte written is - ** an ASCII 'S' character which also happens to be the first byte - ** in the header of every SQLite database. In this way, if there - ** is a race condition such that another thread has already populated - ** the first page of the database, no damage is done. - */ - if( statbuf.st_size==0 && (pFile->fsFlags & SQLITE_FSFLAGS_IS_MSDOS)!=0 ){ - do{ rc = osWrite(fd, "S", 1); }while( rc<0 && errno==EINTR ); - if( rc!=1 ){ - storeLastErrno(pFile, errno); - return SQLITE_IOERR; - } - rc = osFstat(fd, &statbuf); - if( rc!=0 ){ - storeLastErrno(pFile, errno); - return SQLITE_IOERR; - } - } -#endif - - memset(&fileId, 0, sizeof(fileId)); - fileId.dev = statbuf.st_dev; -#if OS_VXWORKS - fileId.pId = pFile->pId; -#else - fileId.ino = statbuf.st_ino; -#endif - pInode = inodeList; - while( pInode && memcmp(&fileId, &pInode->fileId, sizeof(fileId)) ){ - pInode = pInode->pNext; - } - if( pInode==0 ){ - pInode = sqlite3_malloc64( sizeof(*pInode) ); - if( pInode==0 ){ - return SQLITE_NOMEM; - } - memset(pInode, 0, sizeof(*pInode)); - memcpy(&pInode->fileId, &fileId, sizeof(fileId)); - pInode->nRef = 1; - pInode->pNext = inodeList; - pInode->pPrev = 0; - if( inodeList ) inodeList->pPrev = pInode; - inodeList = pInode; - }else{ - pInode->nRef++; - } - *ppInode = pInode; - return SQLITE_OK; -} - -/* -** Return TRUE if pFile has been renamed or unlinked since it was first opened. -*/ -static int fileHasMoved(unixFile *pFile){ -#if OS_VXWORKS - return pFile->pInode!=0 && pFile->pId!=pFile->pInode->fileId.pId; -#else - struct stat buf; - return pFile->pInode!=0 && - (osStat(pFile->zPath, &buf)!=0 || buf.st_ino!=pFile->pInode->fileId.ino); -#endif -} - - -/* -** Check a unixFile that is a database. Verify the following: -** -** (1) There is exactly one hard link on the file -** (2) The file is not a symbolic link -** (3) The file has not been renamed or unlinked -** -** Issue sqlite3_log(SQLITE_WARNING,...) messages if anything is not right. -*/ -static void verifyDbFile(unixFile *pFile){ - struct stat buf; - int rc; - if( pFile->ctrlFlags & UNIXFILE_WARNED ){ - /* One or more of the following warnings have already been issued. Do not - ** repeat them so as not to clutter the error log */ - return; - } - rc = osFstat(pFile->h, &buf); - if( rc!=0 ){ - sqlite3_log(SQLITE_WARNING, "cannot fstat db file %s", pFile->zPath); - pFile->ctrlFlags |= UNIXFILE_WARNED; - return; - } - if( buf.st_nlink==0 && (pFile->ctrlFlags & UNIXFILE_DELETE)==0 ){ - sqlite3_log(SQLITE_WARNING, "file unlinked while open: %s", pFile->zPath); - pFile->ctrlFlags |= UNIXFILE_WARNED; - return; - } - if( buf.st_nlink>1 ){ - sqlite3_log(SQLITE_WARNING, "multiple links to file: %s", pFile->zPath); - pFile->ctrlFlags |= UNIXFILE_WARNED; - return; - } - if( fileHasMoved(pFile) ){ - sqlite3_log(SQLITE_WARNING, "file renamed while open: %s", pFile->zPath); - pFile->ctrlFlags |= UNIXFILE_WARNED; - return; - } -} - - -/* -** This routine checks if there is a RESERVED lock held on the specified -** file by this or any other process. If such a lock is held, set *pResOut -** to a non-zero value otherwise *pResOut is set to zero. The return value -** is set to SQLITE_OK unless an I/O error occurs during lock checking. -*/ -static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){ - int rc = SQLITE_OK; - int reserved = 0; - unixFile *pFile = (unixFile*)id; - - SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; ); - - assert( pFile ); - unixEnterMutex(); /* Because pFile->pInode is shared across threads */ - - /* Check if a thread in this process holds such a lock */ - if( pFile->pInode->eFileLock>SHARED_LOCK ){ - reserved = 1; - } - - /* Otherwise see if some other process holds it. - */ -#ifndef __DJGPP__ - if( !reserved && !pFile->pInode->bProcessLock ){ - struct flock lock; - lock.l_whence = SEEK_SET; - lock.l_start = RESERVED_BYTE; - lock.l_len = 1; - lock.l_type = F_WRLCK; - if( osFcntl(pFile->h, F_GETLK, &lock) ){ - rc = SQLITE_IOERR_CHECKRESERVEDLOCK; - storeLastErrno(pFile, errno); - } else if( lock.l_type!=F_UNLCK ){ - reserved = 1; - } - } -#endif - - unixLeaveMutex(); - OSTRACE(("TEST WR-LOCK %d %d %d (unix)\n", pFile->h, rc, reserved)); - - *pResOut = reserved; - return rc; -} - -/* -** Attempt to set a system-lock on the file pFile. The lock is -** described by pLock. -** -** If the pFile was opened read/write from unix-excl, then the only lock -** ever obtained is an exclusive lock, and it is obtained exactly once -** the first time any lock is attempted. All subsequent system locking -** operations become no-ops. Locking operations still happen internally, -** in order to coordinate access between separate database connections -** within this process, but all of that is handled in memory and the -** operating system does not participate. -** -** This function is a pass-through to fcntl(F_SETLK) if pFile is using -** any VFS other than "unix-excl" or if pFile is opened on "unix-excl" -** and is read-only. -** -** Zero is returned if the call completes successfully, or -1 if a call -** to fcntl() fails. In this case, errno is set appropriately (by fcntl()). -*/ -static int unixFileLock(unixFile *pFile, struct flock *pLock){ - int rc; - unixInodeInfo *pInode = pFile->pInode; - assert( unixMutexHeld() ); - assert( pInode!=0 ); - if( ((pFile->ctrlFlags & UNIXFILE_EXCL)!=0 || pInode->bProcessLock) - && ((pFile->ctrlFlags & UNIXFILE_RDONLY)==0) - ){ - if( pInode->bProcessLock==0 ){ - struct flock lock; - assert( pInode->nLock==0 ); - lock.l_whence = SEEK_SET; - lock.l_start = SHARED_FIRST; - lock.l_len = SHARED_SIZE; - lock.l_type = F_WRLCK; - rc = osFcntl(pFile->h, F_SETLK, &lock); - if( rc<0 ) return rc; - pInode->bProcessLock = 1; - pInode->nLock++; - }else{ - rc = 0; - } - }else{ - rc = osFcntl(pFile->h, F_SETLK, pLock); - } - return rc; -} - -/* -** Lock the file with the lock specified by parameter eFileLock - one -** of the following: -** -** (1) SHARED_LOCK -** (2) RESERVED_LOCK -** (3) PENDING_LOCK -** (4) EXCLUSIVE_LOCK -** -** Sometimes when requesting one lock state, additional lock states -** are inserted in between. The locking might fail on one of the later -** transitions leaving the lock state different from what it started but -** still short of its goal. The following chart shows the allowed -** transitions and the inserted intermediate states: -** -** UNLOCKED -> SHARED -** SHARED -> RESERVED -** SHARED -> (PENDING) -> EXCLUSIVE -** RESERVED -> (PENDING) -> EXCLUSIVE -** PENDING -> EXCLUSIVE -** -** This routine will only increase a lock. Use the sqlite3OsUnlock() -** routine to lower a locking level. -*/ -static int unixLock(sqlite3_file *id, int eFileLock){ - /* The following describes the implementation of the various locks and - ** lock transitions in terms of the POSIX advisory shared and exclusive - ** lock primitives (called read-locks and write-locks below, to avoid - ** confusion with SQLite lock names). The algorithms are complicated - ** slightly in order to be compatible with windows systems simultaneously - ** accessing the same database file, in case that is ever required. - ** - ** Symbols defined in os.h indentify the 'pending byte' and the 'reserved - ** byte', each single bytes at well known offsets, and the 'shared byte - ** range', a range of 510 bytes at a well known offset. - ** - ** To obtain a SHARED lock, a read-lock is obtained on the 'pending - ** byte'. If this is successful, a random byte from the 'shared byte - ** range' is read-locked and the lock on the 'pending byte' released. - ** - ** A process may only obtain a RESERVED lock after it has a SHARED lock. - ** A RESERVED lock is implemented by grabbing a write-lock on the - ** 'reserved byte'. - ** - ** A process may only obtain a PENDING lock after it has obtained a - ** SHARED lock. A PENDING lock is implemented by obtaining a write-lock - ** on the 'pending byte'. This ensures that no new SHARED locks can be - ** obtained, but existing SHARED locks are allowed to persist. A process - ** does not have to obtain a RESERVED lock on the way to a PENDING lock. - ** This property is used by the algorithm for rolling back a journal file - ** after a crash. - ** - ** An EXCLUSIVE lock, obtained after a PENDING lock is held, is - ** implemented by obtaining a write-lock on the entire 'shared byte - ** range'. Since all other locks require a read-lock on one of the bytes - ** within this range, this ensures that no other locks are held on the - ** database. - ** - ** The reason a single byte cannot be used instead of the 'shared byte - ** range' is that some versions of windows do not support read-locks. By - ** locking a random byte from a range, concurrent SHARED locks may exist - ** even if the locking primitive used is always a write-lock. - */ - int rc = SQLITE_OK; - unixFile *pFile = (unixFile*)id; - unixInodeInfo *pInode; - struct flock lock; - int tErrno = 0; - - assert( pFile ); - OSTRACE(("LOCK %d %s was %s(%s,%d) pid=%d (unix)\n", pFile->h, - azFileLock(eFileLock), azFileLock(pFile->eFileLock), - azFileLock(pFile->pInode->eFileLock), pFile->pInode->nShared, - osGetpid(0))); - - /* If there is already a lock of this type or more restrictive on the - ** unixFile, do nothing. Don't use the end_lock: exit path, as - ** unixEnterMutex() hasn't been called yet. - */ - if( pFile->eFileLock>=eFileLock ){ - OSTRACE(("LOCK %d %s ok (already held) (unix)\n", pFile->h, - azFileLock(eFileLock))); - return SQLITE_OK; - } - - /* Make sure the locking sequence is correct. - ** (1) We never move from unlocked to anything higher than shared lock. - ** (2) SQLite never explicitly requests a pendig lock. - ** (3) A shared lock is always held when a reserve lock is requested. - */ - assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK ); - assert( eFileLock!=PENDING_LOCK ); - assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK ); - - /* This mutex is needed because pFile->pInode is shared across threads - */ - unixEnterMutex(); - pInode = pFile->pInode; - - /* If some thread using this PID has a lock via a different unixFile* - ** handle that precludes the requested lock, return BUSY. - */ - if( (pFile->eFileLock!=pInode->eFileLock && - (pInode->eFileLock>=PENDING_LOCK || eFileLock>SHARED_LOCK)) - ){ - rc = SQLITE_BUSY; - goto end_lock; - } - - /* If a SHARED lock is requested, and some thread using this PID already - ** has a SHARED or RESERVED lock, then increment reference counts and - ** return SQLITE_OK. - */ - if( eFileLock==SHARED_LOCK && - (pInode->eFileLock==SHARED_LOCK || pInode->eFileLock==RESERVED_LOCK) ){ - assert( eFileLock==SHARED_LOCK ); - assert( pFile->eFileLock==0 ); - assert( pInode->nShared>0 ); - pFile->eFileLock = SHARED_LOCK; - pInode->nShared++; - pInode->nLock++; - goto end_lock; - } - - - /* A PENDING lock is needed before acquiring a SHARED lock and before - ** acquiring an EXCLUSIVE lock. For the SHARED lock, the PENDING will - ** be released. - */ - lock.l_len = 1L; - lock.l_whence = SEEK_SET; - if( eFileLock==SHARED_LOCK - || (eFileLock==EXCLUSIVE_LOCK && pFile->eFileLock<PENDING_LOCK) - ){ - lock.l_type = (eFileLock==SHARED_LOCK?F_RDLCK:F_WRLCK); - lock.l_start = PENDING_BYTE; - if( unixFileLock(pFile, &lock) ){ - tErrno = errno; - rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); - if( rc!=SQLITE_BUSY ){ - storeLastErrno(pFile, tErrno); - } - goto end_lock; - } - } - - - /* If control gets to this point, then actually go ahead and make - ** operating system calls for the specified lock. - */ - if( eFileLock==SHARED_LOCK ){ - assert( pInode->nShared==0 ); - assert( pInode->eFileLock==0 ); - assert( rc==SQLITE_OK ); - - /* Now get the read-lock */ - lock.l_start = SHARED_FIRST; - lock.l_len = SHARED_SIZE; - if( unixFileLock(pFile, &lock) ){ - tErrno = errno; - rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); - } - - /* Drop the temporary PENDING lock */ - lock.l_start = PENDING_BYTE; - lock.l_len = 1L; - lock.l_type = F_UNLCK; - if( unixFileLock(pFile, &lock) && rc==SQLITE_OK ){ - /* This could happen with a network mount */ - tErrno = errno; - rc = SQLITE_IOERR_UNLOCK; - } - - if( rc ){ - if( rc!=SQLITE_BUSY ){ - storeLastErrno(pFile, tErrno); - } - goto end_lock; - }else{ - pFile->eFileLock = SHARED_LOCK; - pInode->nLock++; - pInode->nShared = 1; - } - }else if( eFileLock==EXCLUSIVE_LOCK && pInode->nShared>1 ){ - /* We are trying for an exclusive lock but another thread in this - ** same process is still holding a shared lock. */ - rc = SQLITE_BUSY; - }else{ - /* The request was for a RESERVED or EXCLUSIVE lock. It is - ** assumed that there is a SHARED or greater lock on the file - ** already. - */ - assert( 0!=pFile->eFileLock ); - lock.l_type = F_WRLCK; - - assert( eFileLock==RESERVED_LOCK || eFileLock==EXCLUSIVE_LOCK ); - if( eFileLock==RESERVED_LOCK ){ - lock.l_start = RESERVED_BYTE; - lock.l_len = 1L; - }else{ - lock.l_start = SHARED_FIRST; - lock.l_len = SHARED_SIZE; - } - - if( unixFileLock(pFile, &lock) ){ - tErrno = errno; - rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); - if( rc!=SQLITE_BUSY ){ - storeLastErrno(pFile, tErrno); - } - } - } - - -#ifdef SQLITE_DEBUG - /* Set up the transaction-counter change checking flags when - ** transitioning from a SHARED to a RESERVED lock. The change - ** from SHARED to RESERVED marks the beginning of a normal - ** write operation (not a hot journal rollback). - */ - if( rc==SQLITE_OK - && pFile->eFileLock<=SHARED_LOCK - && eFileLock==RESERVED_LOCK - ){ - pFile->transCntrChng = 0; - pFile->dbUpdate = 0; - pFile->inNormalWrite = 1; - } -#endif - - - if( rc==SQLITE_OK ){ - pFile->eFileLock = eFileLock; - pInode->eFileLock = eFileLock; - }else if( eFileLock==EXCLUSIVE_LOCK ){ - pFile->eFileLock = PENDING_LOCK; - pInode->eFileLock = PENDING_LOCK; - } - -end_lock: - unixLeaveMutex(); - OSTRACE(("LOCK %d %s %s (unix)\n", pFile->h, azFileLock(eFileLock), - rc==SQLITE_OK ? "ok" : "failed")); - return rc; -} - -/* -** Add the file descriptor used by file handle pFile to the corresponding -** pUnused list. -*/ -static void setPendingFd(unixFile *pFile){ - unixInodeInfo *pInode = pFile->pInode; - UnixUnusedFd *p = pFile->pUnused; - p->pNext = pInode->pUnused; - pInode->pUnused = p; - pFile->h = -1; - pFile->pUnused = 0; -} - -/* -** Lower the locking level on file descriptor pFile to eFileLock. eFileLock -** must be either NO_LOCK or SHARED_LOCK. -** -** If the locking level of the file descriptor is already at or below -** the requested locking level, this routine is a no-op. -** -** If handleNFSUnlock is true, then on downgrading an EXCLUSIVE_LOCK to SHARED -** the byte range is divided into 2 parts and the first part is unlocked then -** set to a read lock, then the other part is simply unlocked. This works -** around a bug in BSD NFS lockd (also seen on MacOSX 10.3+) that fails to -** remove the write lock on a region when a read lock is set. -*/ -static int posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){ - unixFile *pFile = (unixFile*)id; - unixInodeInfo *pInode; - struct flock lock; - int rc = SQLITE_OK; - - assert( pFile ); - OSTRACE(("UNLOCK %d %d was %d(%d,%d) pid=%d (unix)\n", pFile->h, eFileLock, - pFile->eFileLock, pFile->pInode->eFileLock, pFile->pInode->nShared, - osGetpid(0))); - - assert( eFileLock<=SHARED_LOCK ); - if( pFile->eFileLock<=eFileLock ){ - return SQLITE_OK; - } - unixEnterMutex(); - pInode = pFile->pInode; - assert( pInode->nShared!=0 ); - if( pFile->eFileLock>SHARED_LOCK ){ - assert( pInode->eFileLock==pFile->eFileLock ); - -#ifdef SQLITE_DEBUG - /* When reducing a lock such that other processes can start - ** reading the database file again, make sure that the - ** transaction counter was updated if any part of the database - ** file changed. If the transaction counter is not updated, - ** other connections to the same file might not realize that - ** the file has changed and hence might not know to flush their - ** cache. The use of a stale cache can lead to database corruption. - */ - pFile->inNormalWrite = 0; -#endif - - /* downgrading to a shared lock on NFS involves clearing the write lock - ** before establishing the readlock - to avoid a race condition we downgrade - ** the lock in 2 blocks, so that part of the range will be covered by a - ** write lock until the rest is covered by a read lock: - ** 1: [WWWWW] - ** 2: [....W] - ** 3: [RRRRW] - ** 4: [RRRR.] - */ - if( eFileLock==SHARED_LOCK ){ -#if !defined(__APPLE__) || !SQLITE_ENABLE_LOCKING_STYLE - (void)handleNFSUnlock; - assert( handleNFSUnlock==0 ); -#endif -#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE - if( handleNFSUnlock ){ - int tErrno; /* Error code from system call errors */ - off_t divSize = SHARED_SIZE - 1; - - lock.l_type = F_UNLCK; - lock.l_whence = SEEK_SET; - lock.l_start = SHARED_FIRST; - lock.l_len = divSize; - if( unixFileLock(pFile, &lock)==(-1) ){ - tErrno = errno; - rc = SQLITE_IOERR_UNLOCK; - if( IS_LOCK_ERROR(rc) ){ - storeLastErrno(pFile, tErrno); - } - goto end_unlock; - } - lock.l_type = F_RDLCK; - lock.l_whence = SEEK_SET; - lock.l_start = SHARED_FIRST; - lock.l_len = divSize; - if( unixFileLock(pFile, &lock)==(-1) ){ - tErrno = errno; - rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK); - if( IS_LOCK_ERROR(rc) ){ - storeLastErrno(pFile, tErrno); - } - goto end_unlock; - } - lock.l_type = F_UNLCK; - lock.l_whence = SEEK_SET; - lock.l_start = SHARED_FIRST+divSize; - lock.l_len = SHARED_SIZE-divSize; - if( unixFileLock(pFile, &lock)==(-1) ){ - tErrno = errno; - rc = SQLITE_IOERR_UNLOCK; - if( IS_LOCK_ERROR(rc) ){ - storeLastErrno(pFile, tErrno); - } - goto end_unlock; - } - }else -#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */ - { - lock.l_type = F_RDLCK; - lock.l_whence = SEEK_SET; - lock.l_start = SHARED_FIRST; - lock.l_len = SHARED_SIZE; - if( unixFileLock(pFile, &lock) ){ - /* In theory, the call to unixFileLock() cannot fail because another - ** process is holding an incompatible lock. If it does, this - ** indicates that the other process is not following the locking - ** protocol. If this happens, return SQLITE_IOERR_RDLOCK. Returning - ** SQLITE_BUSY would confuse the upper layer (in practice it causes - ** an assert to fail). */ - rc = SQLITE_IOERR_RDLOCK; - storeLastErrno(pFile, errno); - goto end_unlock; - } - } - } - lock.l_type = F_UNLCK; - lock.l_whence = SEEK_SET; - lock.l_start = PENDING_BYTE; - lock.l_len = 2L; assert( PENDING_BYTE+1==RESERVED_BYTE ); - if( unixFileLock(pFile, &lock)==0 ){ - pInode->eFileLock = SHARED_LOCK; - }else{ - rc = SQLITE_IOERR_UNLOCK; - storeLastErrno(pFile, errno); - goto end_unlock; - } - } - if( eFileLock==NO_LOCK ){ - /* Decrement the shared lock counter. Release the lock using an - ** OS call only when all threads in this same process have released - ** the lock. - */ - pInode->nShared--; - if( pInode->nShared==0 ){ - lock.l_type = F_UNLCK; - lock.l_whence = SEEK_SET; - lock.l_start = lock.l_len = 0L; - if( unixFileLock(pFile, &lock)==0 ){ - pInode->eFileLock = NO_LOCK; - }else{ - rc = SQLITE_IOERR_UNLOCK; - storeLastErrno(pFile, errno); - pInode->eFileLock = NO_LOCK; - pFile->eFileLock = NO_LOCK; - } - } - - /* Decrement the count of locks against this same file. When the - ** count reaches zero, close any other file descriptors whose close - ** was deferred because of outstanding locks. - */ - pInode->nLock--; - assert( pInode->nLock>=0 ); - if( pInode->nLock==0 ){ - closePendingFds(pFile); - } - } - -end_unlock: - unixLeaveMutex(); - if( rc==SQLITE_OK ) pFile->eFileLock = eFileLock; - return rc; -} - -/* -** Lower the locking level on file descriptor pFile to eFileLock. eFileLock -** must be either NO_LOCK or SHARED_LOCK. -** -** If the locking level of the file descriptor is already at or below -** the requested locking level, this routine is a no-op. -*/ -static int unixUnlock(sqlite3_file *id, int eFileLock){ -#if SQLITE_MAX_MMAP_SIZE>0 - assert( eFileLock==SHARED_LOCK || ((unixFile *)id)->nFetchOut==0 ); -#endif - return posixUnlock(id, eFileLock, 0); -} - -#if SQLITE_MAX_MMAP_SIZE>0 -static int unixMapfile(unixFile *pFd, i64 nByte); -static void unixUnmapfile(unixFile *pFd); -#endif - -/* -** This function performs the parts of the "close file" operation -** common to all locking schemes. It closes the directory and file -** handles, if they are valid, and sets all fields of the unixFile -** structure to 0. -** -** It is *not* necessary to hold the mutex when this routine is called, -** even on VxWorks. A mutex will be acquired on VxWorks by the -** vxworksReleaseFileId() routine. -*/ -static int closeUnixFile(sqlite3_file *id){ - unixFile *pFile = (unixFile*)id; -#if SQLITE_MAX_MMAP_SIZE>0 - unixUnmapfile(pFile); -#endif - if( pFile->h>=0 ){ - robust_close(pFile, pFile->h, __LINE__); - pFile->h = -1; - } -#if OS_VXWORKS - if( pFile->pId ){ - if( pFile->ctrlFlags & UNIXFILE_DELETE ){ - osUnlink(pFile->pId->zCanonicalName); - } - vxworksReleaseFileId(pFile->pId); - pFile->pId = 0; - } -#endif -#ifdef SQLITE_UNLINK_AFTER_CLOSE - if( pFile->ctrlFlags & UNIXFILE_DELETE ){ - osUnlink(pFile->zPath); - sqlite3_free(*(char**)&pFile->zPath); - pFile->zPath = 0; - } -#endif - OSTRACE(("CLOSE %-3d\n", pFile->h)); - OpenCounter(-1); - sqlite3_free(pFile->pUnused); - memset(pFile, 0, sizeof(unixFile)); - return SQLITE_OK; -} - -/* -** Close a file. -*/ -static int unixClose(sqlite3_file *id){ - int rc = SQLITE_OK; - unixFile *pFile = (unixFile *)id; - verifyDbFile(pFile); - unixUnlock(id, NO_LOCK); - unixEnterMutex(); - - /* unixFile.pInode is always valid here. Otherwise, a different close - ** routine (e.g. nolockClose()) would be called instead. - */ - assert( pFile->pInode->nLock>0 || pFile->pInode->bProcessLock==0 ); - if( ALWAYS(pFile->pInode) && pFile->pInode->nLock ){ - /* If there are outstanding locks, do not actually close the file just - ** yet because that would clear those locks. Instead, add the file - ** descriptor to pInode->pUnused list. It will be automatically closed - ** when the last lock is cleared. - */ - setPendingFd(pFile); - } - releaseInodeInfo(pFile); - rc = closeUnixFile(id); - unixLeaveMutex(); - return rc; -} - -/************** End of the posix advisory lock implementation ***************** -******************************************************************************/ - -/****************************************************************************** -****************************** No-op Locking ********************************** -** -** Of the various locking implementations available, this is by far the -** simplest: locking is ignored. No attempt is made to lock the database -** file for reading or writing. -** -** This locking mode is appropriate for use on read-only databases -** (ex: databases that are burned into CD-ROM, for example.) It can -** also be used if the application employs some external mechanism to -** prevent simultaneous access of the same database by two or more -** database connections. But there is a serious risk of database -** corruption if this locking mode is used in situations where multiple -** database connections are accessing the same database file at the same -** time and one or more of those connections are writing. -*/ - -static int nolockCheckReservedLock(sqlite3_file *NotUsed, int *pResOut){ - UNUSED_PARAMETER(NotUsed); - *pResOut = 0; - return SQLITE_OK; -} -static int nolockLock(sqlite3_file *NotUsed, int NotUsed2){ - UNUSED_PARAMETER2(NotUsed, NotUsed2); - return SQLITE_OK; -} -static int nolockUnlock(sqlite3_file *NotUsed, int NotUsed2){ - UNUSED_PARAMETER2(NotUsed, NotUsed2); - return SQLITE_OK; -} - -/* -** Close the file. -*/ -static int nolockClose(sqlite3_file *id) { - return closeUnixFile(id); -} - -/******************* End of the no-op lock implementation ********************* -******************************************************************************/ - -/****************************************************************************** -************************* Begin dot-file Locking ****************************** -** -** The dotfile locking implementation uses the existence of separate lock -** files (really a directory) to control access to the database. This works -** on just about every filesystem imaginable. But there are serious downsides: -** -** (1) There is zero concurrency. A single reader blocks all other -** connections from reading or writing the database. -** -** (2) An application crash or power loss can leave stale lock files -** sitting around that need to be cleared manually. -** -** Nevertheless, a dotlock is an appropriate locking mode for use if no -** other locking strategy is available. -** -** Dotfile locking works by creating a subdirectory in the same directory as -** the database and with the same name but with a ".lock" extension added. -** The existence of a lock directory implies an EXCLUSIVE lock. All other -** lock types (SHARED, RESERVED, PENDING) are mapped into EXCLUSIVE. -*/ - -/* -** The file suffix added to the data base filename in order to create the -** lock directory. -*/ -#define DOTLOCK_SUFFIX ".lock" - -/* -** This routine checks if there is a RESERVED lock held on the specified -** file by this or any other process. If such a lock is held, set *pResOut -** to a non-zero value otherwise *pResOut is set to zero. The return value -** is set to SQLITE_OK unless an I/O error occurs during lock checking. -** -** In dotfile locking, either a lock exists or it does not. So in this -** variation of CheckReservedLock(), *pResOut is set to true if any lock -** is held on the file and false if the file is unlocked. -*/ -static int dotlockCheckReservedLock(sqlite3_file *id, int *pResOut) { - int rc = SQLITE_OK; - int reserved = 0; - unixFile *pFile = (unixFile*)id; - - SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; ); - - assert( pFile ); - - /* Check if a thread in this process holds such a lock */ - if( pFile->eFileLock>SHARED_LOCK ){ - /* Either this connection or some other connection in the same process - ** holds a lock on the file. No need to check further. */ - reserved = 1; - }else{ - /* The lock is held if and only if the lockfile exists */ - const char *zLockFile = (const char*)pFile->lockingContext; - reserved = osAccess(zLockFile, 0)==0; - } - OSTRACE(("TEST WR-LOCK %d %d %d (dotlock)\n", pFile->h, rc, reserved)); - *pResOut = reserved; - return rc; -} - -/* -** Lock the file with the lock specified by parameter eFileLock - one -** of the following: -** -** (1) SHARED_LOCK -** (2) RESERVED_LOCK -** (3) PENDING_LOCK -** (4) EXCLUSIVE_LOCK -** -** Sometimes when requesting one lock state, additional lock states -** are inserted in between. The locking might fail on one of the later -** transitions leaving the lock state different from what it started but -** still short of its goal. The following chart shows the allowed -** transitions and the inserted intermediate states: -** -** UNLOCKED -> SHARED -** SHARED -> RESERVED -** SHARED -> (PENDING) -> EXCLUSIVE -** RESERVED -> (PENDING) -> EXCLUSIVE -** PENDING -> EXCLUSIVE -** -** This routine will only increase a lock. Use the sqlite3OsUnlock() -** routine to lower a locking level. -** -** With dotfile locking, we really only support state (4): EXCLUSIVE. -** But we track the other locking levels internally. -*/ -static int dotlockLock(sqlite3_file *id, int eFileLock) { - unixFile *pFile = (unixFile*)id; - char *zLockFile = (char *)pFile->lockingContext; - int rc = SQLITE_OK; - - - /* If we have any lock, then the lock file already exists. All we have - ** to do is adjust our internal record of the lock level. - */ - if( pFile->eFileLock > NO_LOCK ){ - pFile->eFileLock = eFileLock; - /* Always update the timestamp on the old file */ -#ifdef HAVE_UTIME - utime(zLockFile, NULL); -#else - utimes(zLockFile, NULL); -#endif - return SQLITE_OK; - } - - /* grab an exclusive lock */ - rc = osMkdir(zLockFile, 0777); - if( rc<0 ){ - /* failed to open/create the lock directory */ - int tErrno = errno; - if( EEXIST == tErrno ){ - rc = SQLITE_BUSY; - } else { - rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); - if( IS_LOCK_ERROR(rc) ){ - storeLastErrno(pFile, tErrno); - } - } - return rc; - } - - /* got it, set the type and return ok */ - pFile->eFileLock = eFileLock; - return rc; -} - -/* -** Lower the locking level on file descriptor pFile to eFileLock. eFileLock -** must be either NO_LOCK or SHARED_LOCK. -** -** If the locking level of the file descriptor is already at or below -** the requested locking level, this routine is a no-op. -** -** When the locking level reaches NO_LOCK, delete the lock file. -*/ -static int dotlockUnlock(sqlite3_file *id, int eFileLock) { - unixFile *pFile = (unixFile*)id; - char *zLockFile = (char *)pFile->lockingContext; - int rc; - - assert( pFile ); - OSTRACE(("UNLOCK %d %d was %d pid=%d (dotlock)\n", pFile->h, eFileLock, - pFile->eFileLock, osGetpid(0))); - assert( eFileLock<=SHARED_LOCK ); - - /* no-op if possible */ - if( pFile->eFileLock==eFileLock ){ - return SQLITE_OK; - } - - /* To downgrade to shared, simply update our internal notion of the - ** lock state. No need to mess with the file on disk. - */ - if( eFileLock==SHARED_LOCK ){ - pFile->eFileLock = SHARED_LOCK; - return SQLITE_OK; - } - - /* To fully unlock the database, delete the lock file */ - assert( eFileLock==NO_LOCK ); - rc = osRmdir(zLockFile); - if( rc<0 && errno==ENOTDIR ) rc = osUnlink(zLockFile); - if( rc<0 ){ - int tErrno = errno; - rc = 0; - if( ENOENT != tErrno ){ - rc = SQLITE_IOERR_UNLOCK; - } - if( IS_LOCK_ERROR(rc) ){ - storeLastErrno(pFile, tErrno); - } - return rc; - } - pFile->eFileLock = NO_LOCK; - return SQLITE_OK; -} - -/* -** Close a file. Make sure the lock has been released before closing. -*/ -static int dotlockClose(sqlite3_file *id) { - int rc = SQLITE_OK; - if( id ){ - unixFile *pFile = (unixFile*)id; - dotlockUnlock(id, NO_LOCK); - sqlite3_free(pFile->lockingContext); - rc = closeUnixFile(id); - } - return rc; -} -/****************** End of the dot-file lock implementation ******************* -******************************************************************************/ - -/****************************************************************************** -************************** Begin flock Locking ******************************** -** -** Use the flock() system call to do file locking. -** -** flock() locking is like dot-file locking in that the various -** fine-grain locking levels supported by SQLite are collapsed into -** a single exclusive lock. In other words, SHARED, RESERVED, and -** PENDING locks are the same thing as an EXCLUSIVE lock. SQLite -** still works when you do this, but concurrency is reduced since -** only a single process can be reading the database at a time. -** -** Omit this section if SQLITE_ENABLE_LOCKING_STYLE is turned off -*/ -#if SQLITE_ENABLE_LOCKING_STYLE - -/* -** Retry flock() calls that fail with EINTR -*/ -#ifdef EINTR -static int robust_flock(int fd, int op){ - int rc; - do{ rc = flock(fd,op); }while( rc<0 && errno==EINTR ); - return rc; -} -#else -# define robust_flock(a,b) flock(a,b) -#endif - - -/* -** This routine checks if there is a RESERVED lock held on the specified -** file by this or any other process. If such a lock is held, set *pResOut -** to a non-zero value otherwise *pResOut is set to zero. The return value -** is set to SQLITE_OK unless an I/O error occurs during lock checking. -*/ -static int flockCheckReservedLock(sqlite3_file *id, int *pResOut){ - int rc = SQLITE_OK; - int reserved = 0; - unixFile *pFile = (unixFile*)id; - - SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; ); - - assert( pFile ); - - /* Check if a thread in this process holds such a lock */ - if( pFile->eFileLock>SHARED_LOCK ){ - reserved = 1; - } - - /* Otherwise see if some other process holds it. */ - if( !reserved ){ - /* attempt to get the lock */ - int lrc = robust_flock(pFile->h, LOCK_EX | LOCK_NB); - if( !lrc ){ - /* got the lock, unlock it */ - lrc = robust_flock(pFile->h, LOCK_UN); - if ( lrc ) { - int tErrno = errno; - /* unlock failed with an error */ - lrc = SQLITE_IOERR_UNLOCK; - if( IS_LOCK_ERROR(lrc) ){ - storeLastErrno(pFile, tErrno); - rc = lrc; - } - } - } else { - int tErrno = errno; - reserved = 1; - /* someone else might have it reserved */ - lrc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); - if( IS_LOCK_ERROR(lrc) ){ - storeLastErrno(pFile, tErrno); - rc = lrc; - } - } - } - OSTRACE(("TEST WR-LOCK %d %d %d (flock)\n", pFile->h, rc, reserved)); - -#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS - if( (rc & SQLITE_IOERR) == SQLITE_IOERR ){ - rc = SQLITE_OK; - reserved=1; - } -#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */ - *pResOut = reserved; - return rc; -} - -/* -** Lock the file with the lock specified by parameter eFileLock - one -** of the following: -** -** (1) SHARED_LOCK -** (2) RESERVED_LOCK -** (3) PENDING_LOCK -** (4) EXCLUSIVE_LOCK -** -** Sometimes when requesting one lock state, additional lock states -** are inserted in between. The locking might fail on one of the later -** transitions leaving the lock state different from what it started but -** still short of its goal. The following chart shows the allowed -** transitions and the inserted intermediate states: -** -** UNLOCKED -> SHARED -** SHARED -> RESERVED -** SHARED -> (PENDING) -> EXCLUSIVE -** RESERVED -> (PENDING) -> EXCLUSIVE -** PENDING -> EXCLUSIVE -** -** flock() only really support EXCLUSIVE locks. We track intermediate -** lock states in the sqlite3_file structure, but all locks SHARED or -** above are really EXCLUSIVE locks and exclude all other processes from -** access the file. -** -** This routine will only increase a lock. Use the sqlite3OsUnlock() -** routine to lower a locking level. -*/ -static int flockLock(sqlite3_file *id, int eFileLock) { - int rc = SQLITE_OK; - unixFile *pFile = (unixFile*)id; - - assert( pFile ); - - /* if we already have a lock, it is exclusive. - ** Just adjust level and punt on outta here. */ - if (pFile->eFileLock > NO_LOCK) { - pFile->eFileLock = eFileLock; - return SQLITE_OK; - } - - /* grab an exclusive lock */ - - if (robust_flock(pFile->h, LOCK_EX | LOCK_NB)) { - int tErrno = errno; - /* didn't get, must be busy */ - rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); - if( IS_LOCK_ERROR(rc) ){ - storeLastErrno(pFile, tErrno); - } - } else { - /* got it, set the type and return ok */ - pFile->eFileLock = eFileLock; - } - OSTRACE(("LOCK %d %s %s (flock)\n", pFile->h, azFileLock(eFileLock), - rc==SQLITE_OK ? "ok" : "failed")); -#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS - if( (rc & SQLITE_IOERR) == SQLITE_IOERR ){ - rc = SQLITE_BUSY; - } -#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */ - return rc; -} - - -/* -** Lower the locking level on file descriptor pFile to eFileLock. eFileLock -** must be either NO_LOCK or SHARED_LOCK. -** -** If the locking level of the file descriptor is already at or below -** the requested locking level, this routine is a no-op. -*/ -static int flockUnlock(sqlite3_file *id, int eFileLock) { - unixFile *pFile = (unixFile*)id; - - assert( pFile ); - OSTRACE(("UNLOCK %d %d was %d pid=%d (flock)\n", pFile->h, eFileLock, - pFile->eFileLock, osGetpid(0))); - assert( eFileLock<=SHARED_LOCK ); - - /* no-op if possible */ - if( pFile->eFileLock==eFileLock ){ - return SQLITE_OK; - } - - /* shared can just be set because we always have an exclusive */ - if (eFileLock==SHARED_LOCK) { - pFile->eFileLock = eFileLock; - return SQLITE_OK; - } - - /* no, really, unlock. */ - if( robust_flock(pFile->h, LOCK_UN) ){ -#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS - return SQLITE_OK; -#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */ - return SQLITE_IOERR_UNLOCK; - }else{ - pFile->eFileLock = NO_LOCK; - return SQLITE_OK; - } -} - -/* -** Close a file. -*/ -static int flockClose(sqlite3_file *id) { - int rc = SQLITE_OK; - if( id ){ - flockUnlock(id, NO_LOCK); - rc = closeUnixFile(id); - } - return rc; -} - -#endif /* SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORK */ - -/******************* End of the flock lock implementation ********************* -******************************************************************************/ - -/****************************************************************************** -************************ Begin Named Semaphore Locking ************************ -** -** Named semaphore locking is only supported on VxWorks. -** -** Semaphore locking is like dot-lock and flock in that it really only -** supports EXCLUSIVE locking. Only a single process can read or write -** the database file at a time. This reduces potential concurrency, but -** makes the lock implementation much easier. -*/ -#if OS_VXWORKS - -/* -** This routine checks if there is a RESERVED lock held on the specified -** file by this or any other process. If such a lock is held, set *pResOut -** to a non-zero value otherwise *pResOut is set to zero. The return value -** is set to SQLITE_OK unless an I/O error occurs during lock checking. -*/ -static int semXCheckReservedLock(sqlite3_file *id, int *pResOut) { - int rc = SQLITE_OK; - int reserved = 0; - unixFile *pFile = (unixFile*)id; - - SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; ); - - assert( pFile ); - - /* Check if a thread in this process holds such a lock */ - if( pFile->eFileLock>SHARED_LOCK ){ - reserved = 1; - } - - /* Otherwise see if some other process holds it. */ - if( !reserved ){ - sem_t *pSem = pFile->pInode->pSem; - - if( sem_trywait(pSem)==-1 ){ - int tErrno = errno; - if( EAGAIN != tErrno ){ - rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_CHECKRESERVEDLOCK); - storeLastErrno(pFile, tErrno); - } else { - /* someone else has the lock when we are in NO_LOCK */ - reserved = (pFile->eFileLock < SHARED_LOCK); - } - }else{ - /* we could have it if we want it */ - sem_post(pSem); - } - } - OSTRACE(("TEST WR-LOCK %d %d %d (sem)\n", pFile->h, rc, reserved)); - - *pResOut = reserved; - return rc; -} - -/* -** Lock the file with the lock specified by parameter eFileLock - one -** of the following: -** -** (1) SHARED_LOCK -** (2) RESERVED_LOCK -** (3) PENDING_LOCK -** (4) EXCLUSIVE_LOCK -** -** Sometimes when requesting one lock state, additional lock states -** are inserted in between. The locking might fail on one of the later -** transitions leaving the lock state different from what it started but -** still short of its goal. The following chart shows the allowed -** transitions and the inserted intermediate states: -** -** UNLOCKED -> SHARED -** SHARED -> RESERVED -** SHARED -> (PENDING) -> EXCLUSIVE -** RESERVED -> (PENDING) -> EXCLUSIVE -** PENDING -> EXCLUSIVE -** -** Semaphore locks only really support EXCLUSIVE locks. We track intermediate -** lock states in the sqlite3_file structure, but all locks SHARED or -** above are really EXCLUSIVE locks and exclude all other processes from -** access the file. -** -** This routine will only increase a lock. Use the sqlite3OsUnlock() -** routine to lower a locking level. -*/ -static int semXLock(sqlite3_file *id, int eFileLock) { - unixFile *pFile = (unixFile*)id; - sem_t *pSem = pFile->pInode->pSem; - int rc = SQLITE_OK; - - /* if we already have a lock, it is exclusive. - ** Just adjust level and punt on outta here. */ - if (pFile->eFileLock > NO_LOCK) { - pFile->eFileLock = eFileLock; - rc = SQLITE_OK; - goto sem_end_lock; - } - - /* lock semaphore now but bail out when already locked. */ - if( sem_trywait(pSem)==-1 ){ - rc = SQLITE_BUSY; - goto sem_end_lock; - } - - /* got it, set the type and return ok */ - pFile->eFileLock = eFileLock; - - sem_end_lock: - return rc; -} - -/* -** Lower the locking level on file descriptor pFile to eFileLock. eFileLock -** must be either NO_LOCK or SHARED_LOCK. -** -** If the locking level of the file descriptor is already at or below -** the requested locking level, this routine is a no-op. -*/ -static int semXUnlock(sqlite3_file *id, int eFileLock) { - unixFile *pFile = (unixFile*)id; - sem_t *pSem = pFile->pInode->pSem; - - assert( pFile ); - assert( pSem ); - OSTRACE(("UNLOCK %d %d was %d pid=%d (sem)\n", pFile->h, eFileLock, - pFile->eFileLock, osGetpid(0))); - assert( eFileLock<=SHARED_LOCK ); - - /* no-op if possible */ - if( pFile->eFileLock==eFileLock ){ - return SQLITE_OK; - } - - /* shared can just be set because we always have an exclusive */ - if (eFileLock==SHARED_LOCK) { - pFile->eFileLock = eFileLock; - return SQLITE_OK; - } - - /* no, really unlock. */ - if ( sem_post(pSem)==-1 ) { - int rc, tErrno = errno; - rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK); - if( IS_LOCK_ERROR(rc) ){ - storeLastErrno(pFile, tErrno); - } - return rc; - } - pFile->eFileLock = NO_LOCK; - return SQLITE_OK; -} - -/* - ** Close a file. - */ -static int semXClose(sqlite3_file *id) { - if( id ){ - unixFile *pFile = (unixFile*)id; - semXUnlock(id, NO_LOCK); - assert( pFile ); - unixEnterMutex(); - releaseInodeInfo(pFile); - unixLeaveMutex(); - closeUnixFile(id); - } - return SQLITE_OK; -} - -#endif /* OS_VXWORKS */ -/* -** Named semaphore locking is only available on VxWorks. -** -*************** End of the named semaphore lock implementation **************** -******************************************************************************/ - - -/****************************************************************************** -*************************** Begin AFP Locking ********************************* -** -** AFP is the Apple Filing Protocol. AFP is a network filesystem found -** on Apple Macintosh computers - both OS9 and OSX. -** -** Third-party implementations of AFP are available. But this code here -** only works on OSX. -*/ - -#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE -/* -** The afpLockingContext structure contains all afp lock specific state -*/ -typedef struct afpLockingContext afpLockingContext; -struct afpLockingContext { - int reserved; - const char *dbPath; /* Name of the open file */ -}; - -struct ByteRangeLockPB2 -{ - unsigned long long offset; /* offset to first byte to lock */ - unsigned long long length; /* nbr of bytes to lock */ - unsigned long long retRangeStart; /* nbr of 1st byte locked if successful */ - unsigned char unLockFlag; /* 1 = unlock, 0 = lock */ - unsigned char startEndFlag; /* 1=rel to end of fork, 0=rel to start */ - int fd; /* file desc to assoc this lock with */ -}; - -#define afpfsByteRangeLock2FSCTL _IOWR('z', 23, struct ByteRangeLockPB2) - -/* -** This is a utility for setting or clearing a bit-range lock on an -** AFP filesystem. -** -** Return SQLITE_OK on success, SQLITE_BUSY on failure. -*/ -static int afpSetLock( - const char *path, /* Name of the file to be locked or unlocked */ - unixFile *pFile, /* Open file descriptor on path */ - unsigned long long offset, /* First byte to be locked */ - unsigned long long length, /* Number of bytes to lock */ - int setLockFlag /* True to set lock. False to clear lock */ -){ - struct ByteRangeLockPB2 pb; - int err; - - pb.unLockFlag = setLockFlag ? 0 : 1; - pb.startEndFlag = 0; - pb.offset = offset; - pb.length = length; - pb.fd = pFile->h; - - OSTRACE(("AFPSETLOCK [%s] for %d%s in range %llx:%llx\n", - (setLockFlag?"ON":"OFF"), pFile->h, (pb.fd==-1?"[testval-1]":""), - offset, length)); - err = fsctl(path, afpfsByteRangeLock2FSCTL, &pb, 0); - if ( err==-1 ) { - int rc; - int tErrno = errno; - OSTRACE(("AFPSETLOCK failed to fsctl() '%s' %d %s\n", - path, tErrno, strerror(tErrno))); -#ifdef SQLITE_IGNORE_AFP_LOCK_ERRORS - rc = SQLITE_BUSY; -#else - rc = sqliteErrorFromPosixError(tErrno, - setLockFlag ? SQLITE_IOERR_LOCK : SQLITE_IOERR_UNLOCK); -#endif /* SQLITE_IGNORE_AFP_LOCK_ERRORS */ - if( IS_LOCK_ERROR(rc) ){ - storeLastErrno(pFile, tErrno); - } - return rc; - } else { - return SQLITE_OK; - } -} - -/* -** This routine checks if there is a RESERVED lock held on the specified -** file by this or any other process. If such a lock is held, set *pResOut -** to a non-zero value otherwise *pResOut is set to zero. The return value -** is set to SQLITE_OK unless an I/O error occurs during lock checking. -*/ -static int afpCheckReservedLock(sqlite3_file *id, int *pResOut){ - int rc = SQLITE_OK; - int reserved = 0; - unixFile *pFile = (unixFile*)id; - afpLockingContext *context; - - SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; ); - - assert( pFile ); - context = (afpLockingContext *) pFile->lockingContext; - if( context->reserved ){ - *pResOut = 1; - return SQLITE_OK; - } - unixEnterMutex(); /* Because pFile->pInode is shared across threads */ - - /* Check if a thread in this process holds such a lock */ - if( pFile->pInode->eFileLock>SHARED_LOCK ){ - reserved = 1; - } - - /* Otherwise see if some other process holds it. - */ - if( !reserved ){ - /* lock the RESERVED byte */ - int lrc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1); - if( SQLITE_OK==lrc ){ - /* if we succeeded in taking the reserved lock, unlock it to restore - ** the original state */ - lrc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0); - } else { - /* if we failed to get the lock then someone else must have it */ - reserved = 1; - } - if( IS_LOCK_ERROR(lrc) ){ - rc=lrc; - } - } - - unixLeaveMutex(); - OSTRACE(("TEST WR-LOCK %d %d %d (afp)\n", pFile->h, rc, reserved)); - - *pResOut = reserved; - return rc; -} - -/* -** Lock the file with the lock specified by parameter eFileLock - one -** of the following: -** -** (1) SHARED_LOCK -** (2) RESERVED_LOCK -** (3) PENDING_LOCK -** (4) EXCLUSIVE_LOCK -** -** Sometimes when requesting one lock state, additional lock states -** are inserted in between. The locking might fail on one of the later -** transitions leaving the lock state different from what it started but -** still short of its goal. The following chart shows the allowed -** transitions and the inserted intermediate states: -** -** UNLOCKED -> SHARED -** SHARED -> RESERVED -** SHARED -> (PENDING) -> EXCLUSIVE -** RESERVED -> (PENDING) -> EXCLUSIVE -** PENDING -> EXCLUSIVE -** -** This routine will only increase a lock. Use the sqlite3OsUnlock() -** routine to lower a locking level. -*/ -static int afpLock(sqlite3_file *id, int eFileLock){ - int rc = SQLITE_OK; - unixFile *pFile = (unixFile*)id; - unixInodeInfo *pInode = pFile->pInode; - afpLockingContext *context = (afpLockingContext *) pFile->lockingContext; - - assert( pFile ); - OSTRACE(("LOCK %d %s was %s(%s,%d) pid=%d (afp)\n", pFile->h, - azFileLock(eFileLock), azFileLock(pFile->eFileLock), - azFileLock(pInode->eFileLock), pInode->nShared , osGetpid(0))); - - /* If there is already a lock of this type or more restrictive on the - ** unixFile, do nothing. Don't use the afp_end_lock: exit path, as - ** unixEnterMutex() hasn't been called yet. - */ - if( pFile->eFileLock>=eFileLock ){ - OSTRACE(("LOCK %d %s ok (already held) (afp)\n", pFile->h, - azFileLock(eFileLock))); - return SQLITE_OK; - } - - /* Make sure the locking sequence is correct - ** (1) We never move from unlocked to anything higher than shared lock. - ** (2) SQLite never explicitly requests a pendig lock. - ** (3) A shared lock is always held when a reserve lock is requested. - */ - assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK ); - assert( eFileLock!=PENDING_LOCK ); - assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK ); - - /* This mutex is needed because pFile->pInode is shared across threads - */ - unixEnterMutex(); - pInode = pFile->pInode; - - /* If some thread using this PID has a lock via a different unixFile* - ** handle that precludes the requested lock, return BUSY. - */ - if( (pFile->eFileLock!=pInode->eFileLock && - (pInode->eFileLock>=PENDING_LOCK || eFileLock>SHARED_LOCK)) - ){ - rc = SQLITE_BUSY; - goto afp_end_lock; - } - - /* If a SHARED lock is requested, and some thread using this PID already - ** has a SHARED or RESERVED lock, then increment reference counts and - ** return SQLITE_OK. - */ - if( eFileLock==SHARED_LOCK && - (pInode->eFileLock==SHARED_LOCK || pInode->eFileLock==RESERVED_LOCK) ){ - assert( eFileLock==SHARED_LOCK ); - assert( pFile->eFileLock==0 ); - assert( pInode->nShared>0 ); - pFile->eFileLock = SHARED_LOCK; - pInode->nShared++; - pInode->nLock++; - goto afp_end_lock; - } - - /* A PENDING lock is needed before acquiring a SHARED lock and before - ** acquiring an EXCLUSIVE lock. For the SHARED lock, the PENDING will - ** be released. - */ - if( eFileLock==SHARED_LOCK - || (eFileLock==EXCLUSIVE_LOCK && pFile->eFileLock<PENDING_LOCK) - ){ - int failed; - failed = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 1); - if (failed) { - rc = failed; - goto afp_end_lock; - } - } - - /* If control gets to this point, then actually go ahead and make - ** operating system calls for the specified lock. - */ - if( eFileLock==SHARED_LOCK ){ - int lrc1, lrc2, lrc1Errno = 0; - long lk, mask; - - assert( pInode->nShared==0 ); - assert( pInode->eFileLock==0 ); - - mask = (sizeof(long)==8) ? LARGEST_INT64 : 0x7fffffff; - /* Now get the read-lock SHARED_LOCK */ - /* note that the quality of the randomness doesn't matter that much */ - lk = random(); - pInode->sharedByte = (lk & mask)%(SHARED_SIZE - 1); - lrc1 = afpSetLock(context->dbPath, pFile, - SHARED_FIRST+pInode->sharedByte, 1, 1); - if( IS_LOCK_ERROR(lrc1) ){ - lrc1Errno = pFile->lastErrno; - } - /* Drop the temporary PENDING lock */ - lrc2 = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0); - - if( IS_LOCK_ERROR(lrc1) ) { - storeLastErrno(pFile, lrc1Errno); - rc = lrc1; - goto afp_end_lock; - } else if( IS_LOCK_ERROR(lrc2) ){ - rc = lrc2; - goto afp_end_lock; - } else if( lrc1 != SQLITE_OK ) { - rc = lrc1; - } else { - pFile->eFileLock = SHARED_LOCK; - pInode->nLock++; - pInode->nShared = 1; - } - }else if( eFileLock==EXCLUSIVE_LOCK && pInode->nShared>1 ){ - /* We are trying for an exclusive lock but another thread in this - ** same process is still holding a shared lock. */ - rc = SQLITE_BUSY; - }else{ - /* The request was for a RESERVED or EXCLUSIVE lock. It is - ** assumed that there is a SHARED or greater lock on the file - ** already. - */ - int failed = 0; - assert( 0!=pFile->eFileLock ); - if (eFileLock >= RESERVED_LOCK && pFile->eFileLock < RESERVED_LOCK) { - /* Acquire a RESERVED lock */ - failed = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1); - if( !failed ){ - context->reserved = 1; - } - } - if (!failed && eFileLock == EXCLUSIVE_LOCK) { - /* Acquire an EXCLUSIVE lock */ - - /* Remove the shared lock before trying the range. we'll need to - ** reestablish the shared lock if we can't get the afpUnlock - */ - if( !(failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST + - pInode->sharedByte, 1, 0)) ){ - int failed2 = SQLITE_OK; - /* now attemmpt to get the exclusive lock range */ - failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST, - SHARED_SIZE, 1); - if( failed && (failed2 = afpSetLock(context->dbPath, pFile, - SHARED_FIRST + pInode->sharedByte, 1, 1)) ){ - /* Can't reestablish the shared lock. Sqlite can't deal, this is - ** a critical I/O error - */ - rc = ((failed & SQLITE_IOERR) == SQLITE_IOERR) ? failed2 : - SQLITE_IOERR_LOCK; - goto afp_end_lock; - } - }else{ - rc = failed; - } - } - if( failed ){ - rc = failed; - } - } - - if( rc==SQLITE_OK ){ - pFile->eFileLock = eFileLock; - pInode->eFileLock = eFileLock; - }else if( eFileLock==EXCLUSIVE_LOCK ){ - pFile->eFileLock = PENDING_LOCK; - pInode->eFileLock = PENDING_LOCK; - } - -afp_end_lock: - unixLeaveMutex(); - OSTRACE(("LOCK %d %s %s (afp)\n", pFile->h, azFileLock(eFileLock), - rc==SQLITE_OK ? "ok" : "failed")); - return rc; -} - -/* -** Lower the locking level on file descriptor pFile to eFileLock. eFileLock -** must be either NO_LOCK or SHARED_LOCK. -** -** If the locking level of the file descriptor is already at or below -** the requested locking level, this routine is a no-op. -*/ -static int afpUnlock(sqlite3_file *id, int eFileLock) { - int rc = SQLITE_OK; - unixFile *pFile = (unixFile*)id; - unixInodeInfo *pInode; - afpLockingContext *context = (afpLockingContext *) pFile->lockingContext; - int skipShared = 0; -#ifdef SQLITE_TEST - int h = pFile->h; -#endif - - assert( pFile ); - OSTRACE(("UNLOCK %d %d was %d(%d,%d) pid=%d (afp)\n", pFile->h, eFileLock, - pFile->eFileLock, pFile->pInode->eFileLock, pFile->pInode->nShared, - osGetpid(0))); - - assert( eFileLock<=SHARED_LOCK ); - if( pFile->eFileLock<=eFileLock ){ - return SQLITE_OK; - } - unixEnterMutex(); - pInode = pFile->pInode; - assert( pInode->nShared!=0 ); - if( pFile->eFileLock>SHARED_LOCK ){ - assert( pInode->eFileLock==pFile->eFileLock ); - SimulateIOErrorBenign(1); - SimulateIOError( h=(-1) ) - SimulateIOErrorBenign(0); - -#ifdef SQLITE_DEBUG - /* When reducing a lock such that other processes can start - ** reading the database file again, make sure that the - ** transaction counter was updated if any part of the database - ** file changed. If the transaction counter is not updated, - ** other connections to the same file might not realize that - ** the file has changed and hence might not know to flush their - ** cache. The use of a stale cache can lead to database corruption. - */ - assert( pFile->inNormalWrite==0 - || pFile->dbUpdate==0 - || pFile->transCntrChng==1 ); - pFile->inNormalWrite = 0; -#endif - - if( pFile->eFileLock==EXCLUSIVE_LOCK ){ - rc = afpSetLock(context->dbPath, pFile, SHARED_FIRST, SHARED_SIZE, 0); - if( rc==SQLITE_OK && (eFileLock==SHARED_LOCK || pInode->nShared>1) ){ - /* only re-establish the shared lock if necessary */ - int sharedLockByte = SHARED_FIRST+pInode->sharedByte; - rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 1); - } else { - skipShared = 1; - } - } - if( rc==SQLITE_OK && pFile->eFileLock>=PENDING_LOCK ){ - rc = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0); - } - if( rc==SQLITE_OK && pFile->eFileLock>=RESERVED_LOCK && context->reserved ){ - rc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0); - if( !rc ){ - context->reserved = 0; - } - } - if( rc==SQLITE_OK && (eFileLock==SHARED_LOCK || pInode->nShared>1)){ - pInode->eFileLock = SHARED_LOCK; - } - } - if( rc==SQLITE_OK && eFileLock==NO_LOCK ){ - - /* Decrement the shared lock counter. Release the lock using an - ** OS call only when all threads in this same process have released - ** the lock. - */ - unsigned long long sharedLockByte = SHARED_FIRST+pInode->sharedByte; - pInode->nShared--; - if( pInode->nShared==0 ){ - SimulateIOErrorBenign(1); - SimulateIOError( h=(-1) ) - SimulateIOErrorBenign(0); - if( !skipShared ){ - rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 0); - } - if( !rc ){ - pInode->eFileLock = NO_LOCK; - pFile->eFileLock = NO_LOCK; - } - } - if( rc==SQLITE_OK ){ - pInode->nLock--; - assert( pInode->nLock>=0 ); - if( pInode->nLock==0 ){ - closePendingFds(pFile); - } - } - } - - unixLeaveMutex(); - if( rc==SQLITE_OK ) pFile->eFileLock = eFileLock; - return rc; -} - -/* -** Close a file & cleanup AFP specific locking context -*/ -static int afpClose(sqlite3_file *id) { - int rc = SQLITE_OK; - if( id ){ - unixFile *pFile = (unixFile*)id; - afpUnlock(id, NO_LOCK); - unixEnterMutex(); - if( pFile->pInode && pFile->pInode->nLock ){ - /* If there are outstanding locks, do not actually close the file just - ** yet because that would clear those locks. Instead, add the file - ** descriptor to pInode->aPending. It will be automatically closed when - ** the last lock is cleared. - */ - setPendingFd(pFile); - } - releaseInodeInfo(pFile); - sqlite3_free(pFile->lockingContext); - rc = closeUnixFile(id); - unixLeaveMutex(); - } - return rc; -} - -#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */ -/* -** The code above is the AFP lock implementation. The code is specific -** to MacOSX and does not work on other unix platforms. No alternative -** is available. If you don't compile for a mac, then the "unix-afp" -** VFS is not available. -** -********************* End of the AFP lock implementation ********************** -******************************************************************************/ - -/****************************************************************************** -*************************** Begin NFS Locking ********************************/ - -#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE -/* - ** Lower the locking level on file descriptor pFile to eFileLock. eFileLock - ** must be either NO_LOCK or SHARED_LOCK. - ** - ** If the locking level of the file descriptor is already at or below - ** the requested locking level, this routine is a no-op. - */ -static int nfsUnlock(sqlite3_file *id, int eFileLock){ - return posixUnlock(id, eFileLock, 1); -} - -#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */ -/* -** The code above is the NFS lock implementation. The code is specific -** to MacOSX and does not work on other unix platforms. No alternative -** is available. -** -********************* End of the NFS lock implementation ********************** -******************************************************************************/ - -/****************************************************************************** -**************** Non-locking sqlite3_file methods ***************************** -** -** The next division contains implementations for all methods of the -** sqlite3_file object other than the locking methods. The locking -** methods were defined in divisions above (one locking method per -** division). Those methods that are common to all locking modes -** are gather together into this division. -*/ - -/* -** Seek to the offset passed as the second argument, then read cnt -** bytes into pBuf. Return the number of bytes actually read. -** -** NB: If you define USE_PREAD or USE_PREAD64, then it might also -** be necessary to define _XOPEN_SOURCE to be 500. This varies from -** one system to another. Since SQLite does not define USE_PREAD -** in any form by default, we will not attempt to define _XOPEN_SOURCE. -** See tickets #2741 and #2681. -** -** To avoid stomping the errno value on a failed read the lastErrno value -** is set before returning. -*/ -static int seekAndRead(unixFile *id, sqlite3_int64 offset, void *pBuf, int cnt){ - int got; - int prior = 0; -#if (!defined(USE_PREAD) && !defined(USE_PREAD64)) - i64 newOffset; -#endif - TIMER_START; - assert( cnt==(cnt&0x1ffff) ); - assert( id->h>2 ); - do{ -#if defined(USE_PREAD) - got = osPread(id->h, pBuf, cnt, offset); - SimulateIOError( got = -1 ); -#elif defined(USE_PREAD64) - got = osPread64(id->h, pBuf, cnt, offset); - SimulateIOError( got = -1 ); -#else - newOffset = lseek(id->h, offset, SEEK_SET); - SimulateIOError( newOffset-- ); - if( newOffset!=offset ){ - if( newOffset == -1 ){ - storeLastErrno((unixFile*)id, errno); - }else{ - storeLastErrno((unixFile*)id, 0); - } - return -1; - } - got = osRead(id->h, pBuf, cnt); -#endif - if( got==cnt ) break; - if( got<0 ){ - if( errno==EINTR ){ got = 1; continue; } - prior = 0; - storeLastErrno((unixFile*)id, errno); - break; - }else if( got>0 ){ - cnt -= got; - offset += got; - prior += got; - pBuf = (void*)(got + (char*)pBuf); - } - }while( got>0 ); - TIMER_END; - OSTRACE(("READ %-3d %5d %7lld %llu\n", - id->h, got+prior, offset-prior, TIMER_ELAPSED)); - return got+prior; -} - -/* -** Read data from a file into a buffer. Return SQLITE_OK if all -** bytes were read successfully and SQLITE_IOERR if anything goes -** wrong. -*/ -static int unixRead( - sqlite3_file *id, - void *pBuf, - int amt, - sqlite3_int64 offset -){ - unixFile *pFile = (unixFile *)id; - int got; - assert( id ); - assert( offset>=0 ); - assert( amt>0 ); - - /* If this is a database file (not a journal, master-journal or temp - ** file), the bytes in the locking range should never be read or written. */ -#if 0 - assert( pFile->pUnused==0 - || offset>=PENDING_BYTE+512 - || offset+amt<=PENDING_BYTE - ); -#endif - -#if SQLITE_MAX_MMAP_SIZE>0 - /* Deal with as much of this read request as possible by transfering - ** data from the memory mapping using memcpy(). */ - if( offset<pFile->mmapSize ){ - if( offset+amt <= pFile->mmapSize ){ - memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], amt); - return SQLITE_OK; - }else{ - int nCopy = pFile->mmapSize - offset; - memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], nCopy); - pBuf = &((u8 *)pBuf)[nCopy]; - amt -= nCopy; - offset += nCopy; - } - } -#endif - - got = seekAndRead(pFile, offset, pBuf, amt); - if( got==amt ){ - return SQLITE_OK; - }else if( got<0 ){ - /* lastErrno set by seekAndRead */ - return SQLITE_IOERR_READ; - }else{ - storeLastErrno(pFile, 0); /* not a system error */ - /* Unread parts of the buffer must be zero-filled */ - memset(&((char*)pBuf)[got], 0, amt-got); - return SQLITE_IOERR_SHORT_READ; - } -} - -/* -** Attempt to seek the file-descriptor passed as the first argument to -** absolute offset iOff, then attempt to write nBuf bytes of data from -** pBuf to it. If an error occurs, return -1 and set *piErrno. Otherwise, -** return the actual number of bytes written (which may be less than -** nBuf). -*/ -static int seekAndWriteFd( - int fd, /* File descriptor to write to */ - i64 iOff, /* File offset to begin writing at */ - const void *pBuf, /* Copy data from this buffer to the file */ - int nBuf, /* Size of buffer pBuf in bytes */ - int *piErrno /* OUT: Error number if error occurs */ -){ - int rc = 0; /* Value returned by system call */ - - assert( nBuf==(nBuf&0x1ffff) ); - assert( fd>2 ); - nBuf &= 0x1ffff; - TIMER_START; - -#if defined(USE_PREAD) - do{ rc = (int)osPwrite(fd, pBuf, nBuf, iOff); }while( rc<0 && errno==EINTR ); -#elif defined(USE_PREAD64) - do{ rc = (int)osPwrite64(fd, pBuf, nBuf, iOff);}while( rc<0 && errno==EINTR); -#else - do{ - i64 iSeek = lseek(fd, iOff, SEEK_SET); - SimulateIOError( iSeek-- ); - - if( iSeek!=iOff ){ - if( piErrno ) *piErrno = (iSeek==-1 ? errno : 0); - return -1; - } - rc = osWrite(fd, pBuf, nBuf); - }while( rc<0 && errno==EINTR ); -#endif - - TIMER_END; - OSTRACE(("WRITE %-3d %5d %7lld %llu\n", fd, rc, iOff, TIMER_ELAPSED)); - - if( rc<0 && piErrno ) *piErrno = errno; - return rc; -} - - -/* -** Seek to the offset in id->offset then read cnt bytes into pBuf. -** Return the number of bytes actually read. Update the offset. -** -** To avoid stomping the errno value on a failed write the lastErrno value -** is set before returning. -*/ -static int seekAndWrite(unixFile *id, i64 offset, const void *pBuf, int cnt){ - return seekAndWriteFd(id->h, offset, pBuf, cnt, &id->lastErrno); -} - - -/* -** Write data from a buffer into a file. Return SQLITE_OK on success -** or some other error code on failure. -*/ -static int unixWrite( - sqlite3_file *id, - const void *pBuf, - int amt, - sqlite3_int64 offset -){ - unixFile *pFile = (unixFile*)id; - int wrote = 0; - assert( id ); - assert( amt>0 ); - - /* If this is a database file (not a journal, master-journal or temp - ** file), the bytes in the locking range should never be read or written. */ -#if 0 - assert( pFile->pUnused==0 - || offset>=PENDING_BYTE+512 - || offset+amt<=PENDING_BYTE - ); -#endif - -#ifdef SQLITE_DEBUG - /* If we are doing a normal write to a database file (as opposed to - ** doing a hot-journal rollback or a write to some file other than a - ** normal database file) then record the fact that the database - ** has changed. If the transaction counter is modified, record that - ** fact too. - */ - if( pFile->inNormalWrite ){ - pFile->dbUpdate = 1; /* The database has been modified */ - if( offset<=24 && offset+amt>=27 ){ - int rc; - char oldCntr[4]; - SimulateIOErrorBenign(1); - rc = seekAndRead(pFile, 24, oldCntr, 4); - SimulateIOErrorBenign(0); - if( rc!=4 || memcmp(oldCntr, &((char*)pBuf)[24-offset], 4)!=0 ){ - pFile->transCntrChng = 1; /* The transaction counter has changed */ - } - } - } -#endif - -#if SQLITE_MAX_MMAP_SIZE>0 - /* Deal with as much of this write request as possible by transfering - ** data from the memory mapping using memcpy(). */ - if( offset<pFile->mmapSize ){ - if( offset+amt <= pFile->mmapSize ){ - memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, amt); - return SQLITE_OK; - }else{ - int nCopy = pFile->mmapSize - offset; - memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, nCopy); - pBuf = &((u8 *)pBuf)[nCopy]; - amt -= nCopy; - offset += nCopy; - } - } -#endif - - while( (wrote = seekAndWrite(pFile, offset, pBuf, amt))<amt && wrote>0 ){ - amt -= wrote; - offset += wrote; - pBuf = &((char*)pBuf)[wrote]; - } - SimulateIOError(( wrote=(-1), amt=1 )); - SimulateDiskfullError(( wrote=0, amt=1 )); - - if( amt>wrote ){ - if( wrote<0 && pFile->lastErrno!=ENOSPC ){ - /* lastErrno set by seekAndWrite */ - return SQLITE_IOERR_WRITE; - }else{ - storeLastErrno(pFile, 0); /* not a system error */ - return SQLITE_FULL; - } - } - - return SQLITE_OK; -} - -#ifdef SQLITE_TEST -/* -** Count the number of fullsyncs and normal syncs. This is used to test -** that syncs and fullsyncs are occurring at the right times. -*/ -int sqlite3_sync_count = 0; -int sqlite3_fullsync_count = 0; -#endif - -/* -** We do not trust systems to provide a working fdatasync(). Some do. -** Others do no. To be safe, we will stick with the (slightly slower) -** fsync(). If you know that your system does support fdatasync() correctly, -** then simply compile with -Dfdatasync=fdatasync or -DHAVE_FDATASYNC -*/ -#if !defined(fdatasync) && !HAVE_FDATASYNC -# define fdatasync fsync -#endif - -/* -** Define HAVE_FULLFSYNC to 0 or 1 depending on whether or not -** the F_FULLFSYNC macro is defined. F_FULLFSYNC is currently -** only available on Mac OS X. But that could change. -*/ -#ifdef F_FULLFSYNC -# define HAVE_FULLFSYNC 1 -#else -# define HAVE_FULLFSYNC 0 -#endif - - -/* -** The fsync() system call does not work as advertised on many -** unix systems. The following procedure is an attempt to make -** it work better. -** -** The SQLITE_NO_SYNC macro disables all fsync()s. This is useful -** for testing when we want to run through the test suite quickly. -** You are strongly advised *not* to deploy with SQLITE_NO_SYNC -** enabled, however, since with SQLITE_NO_SYNC enabled, an OS crash -** or power failure will likely corrupt the database file. -** -** SQLite sets the dataOnly flag if the size of the file is unchanged. -** The idea behind dataOnly is that it should only write the file content -** to disk, not the inode. We only set dataOnly if the file size is -** unchanged since the file size is part of the inode. However, -** Ted Ts'o tells us that fdatasync() will also write the inode if the -** file size has changed. The only real difference between fdatasync() -** and fsync(), Ted tells us, is that fdatasync() will not flush the -** inode if the mtime or owner or other inode attributes have changed. -** We only care about the file size, not the other file attributes, so -** as far as SQLite is concerned, an fdatasync() is always adequate. -** So, we always use fdatasync() if it is available, regardless of -** the value of the dataOnly flag. -*/ -static int full_fsync(int fd, int fullSync, int dataOnly){ - int rc; - - /* The following "ifdef/elif/else/" block has the same structure as - ** the one below. It is replicated here solely to avoid cluttering - ** up the real code with the UNUSED_PARAMETER() macros. - */ -#ifdef SQLITE_NO_SYNC - UNUSED_PARAMETER(fd); - UNUSED_PARAMETER(fullSync); - UNUSED_PARAMETER(dataOnly); -#elif HAVE_FULLFSYNC - UNUSED_PARAMETER(dataOnly); -#else - UNUSED_PARAMETER(fullSync); - UNUSED_PARAMETER(dataOnly); -#endif - - /* Record the number of times that we do a normal fsync() and - ** FULLSYNC. This is used during testing to verify that this procedure - ** gets called with the correct arguments. - */ -#ifdef SQLITE_TEST - if( fullSync ) sqlite3_fullsync_count++; - sqlite3_sync_count++; -#endif - - /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a - ** no-op - */ -#ifdef SQLITE_NO_SYNC - rc = SQLITE_OK; -#elif HAVE_FULLFSYNC - if( fullSync ){ - rc = osFcntl(fd, F_FULLFSYNC, 0); - }else{ - rc = 1; - } - /* If the FULLFSYNC failed, fall back to attempting an fsync(). - ** It shouldn't be possible for fullfsync to fail on the local - ** file system (on OSX), so failure indicates that FULLFSYNC - ** isn't supported for this file system. So, attempt an fsync - ** and (for now) ignore the overhead of a superfluous fcntl call. - ** It'd be better to detect fullfsync support once and avoid - ** the fcntl call every time sync is called. - */ - if( rc ) rc = fsync(fd); - -#elif defined(__APPLE__) - /* fdatasync() on HFS+ doesn't yet flush the file size if it changed correctly - ** so currently we default to the macro that redefines fdatasync to fsync - */ - rc = fsync(fd); -#else - rc = fdatasync(fd); -#if OS_VXWORKS - if( rc==-1 && errno==ENOTSUP ){ - rc = fsync(fd); - } -#endif /* OS_VXWORKS */ -#endif /* ifdef SQLITE_NO_SYNC elif HAVE_FULLFSYNC */ - - if( OS_VXWORKS && rc!= -1 ){ - rc = 0; - } - return rc; -} - -/* -** Open a file descriptor to the directory containing file zFilename. -** If successful, *pFd is set to the opened file descriptor and -** SQLITE_OK is returned. If an error occurs, either SQLITE_NOMEM -** or SQLITE_CANTOPEN is returned and *pFd is set to an undefined -** value. -** -** The directory file descriptor is used for only one thing - to -** fsync() a directory to make sure file creation and deletion events -** are flushed to disk. Such fsyncs are not needed on newer -** journaling filesystems, but are required on older filesystems. -** -** This routine can be overridden using the xSetSysCall interface. -** The ability to override this routine was added in support of the -** chromium sandbox. Opening a directory is a security risk (we are -** told) so making it overrideable allows the chromium sandbox to -** replace this routine with a harmless no-op. To make this routine -** a no-op, replace it with a stub that returns SQLITE_OK but leaves -** *pFd set to a negative number. -** -** If SQLITE_OK is returned, the caller is responsible for closing -** the file descriptor *pFd using close(). -*/ -static int openDirectory(const char *zFilename, int *pFd){ - int ii; - int fd = -1; - char zDirname[MAX_PATHNAME+1]; - - sqlite3_snprintf(MAX_PATHNAME, zDirname, "%s", zFilename); - for(ii=(int)strlen(zDirname); ii>1 && zDirname[ii]!='/'; ii--); - if( ii>0 ){ - zDirname[ii] = '\0'; - fd = robust_open(zDirname, O_RDONLY|O_BINARY, 0); - if( fd>=0 ){ - OSTRACE(("OPENDIR %-3d %s\n", fd, zDirname)); - } - } - *pFd = fd; - return (fd>=0?SQLITE_OK:unixLogError(SQLITE_CANTOPEN_BKPT, "open", zDirname)); -} - -/* -** Make sure all writes to a particular file are committed to disk. -** -** If dataOnly==0 then both the file itself and its metadata (file -** size, access time, etc) are synced. If dataOnly!=0 then only the -** file data is synced. -** -** Under Unix, also make sure that the directory entry for the file -** has been created by fsync-ing the directory that contains the file. -** If we do not do this and we encounter a power failure, the directory -** entry for the journal might not exist after we reboot. The next -** SQLite to access the file will not know that the journal exists (because -** the directory entry for the journal was never created) and the transaction -** will not roll back - possibly leading to database corruption. -*/ -static int unixSync(sqlite3_file *id, int flags){ - int rc; - unixFile *pFile = (unixFile*)id; - - int isDataOnly = (flags&SQLITE_SYNC_DATAONLY); - int isFullsync = (flags&0x0F)==SQLITE_SYNC_FULL; - - /* Check that one of SQLITE_SYNC_NORMAL or FULL was passed */ - assert((flags&0x0F)==SQLITE_SYNC_NORMAL - || (flags&0x0F)==SQLITE_SYNC_FULL - ); - - /* Unix cannot, but some systems may return SQLITE_FULL from here. This - ** line is to test that doing so does not cause any problems. - */ - SimulateDiskfullError( return SQLITE_FULL ); - - assert( pFile ); - OSTRACE(("SYNC %-3d\n", pFile->h)); - rc = full_fsync(pFile->h, isFullsync, isDataOnly); - SimulateIOError( rc=1 ); - if( rc ){ - storeLastErrno(pFile, errno); - return unixLogError(SQLITE_IOERR_FSYNC, "full_fsync", pFile->zPath); - } - - /* Also fsync the directory containing the file if the DIRSYNC flag - ** is set. This is a one-time occurrence. Many systems (examples: AIX) - ** are unable to fsync a directory, so ignore errors on the fsync. - */ - if( pFile->ctrlFlags & UNIXFILE_DIRSYNC ){ - int dirfd; - OSTRACE(("DIRSYNC %s (have_fullfsync=%d fullsync=%d)\n", pFile->zPath, - HAVE_FULLFSYNC, isFullsync)); - rc = osOpenDirectory(pFile->zPath, &dirfd); - if( rc==SQLITE_OK && dirfd>=0 ){ - full_fsync(dirfd, 0, 0); - robust_close(pFile, dirfd, __LINE__); - }else if( rc==SQLITE_CANTOPEN ){ - rc = SQLITE_OK; - } - pFile->ctrlFlags &= ~UNIXFILE_DIRSYNC; - } - return rc; -} - -/* -** Truncate an open file to a specified size -*/ -static int unixTruncate(sqlite3_file *id, i64 nByte){ - unixFile *pFile = (unixFile *)id; - int rc; - assert( pFile ); - SimulateIOError( return SQLITE_IOERR_TRUNCATE ); - - /* If the user has configured a chunk-size for this file, truncate the - ** file so that it consists of an integer number of chunks (i.e. the - ** actual file size after the operation may be larger than the requested - ** size). - */ - if( pFile->szChunk>0 ){ - nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk; - } - - rc = robust_ftruncate(pFile->h, nByte); - if( rc ){ - storeLastErrno(pFile, errno); - return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath); - }else{ -#ifdef SQLITE_DEBUG - /* If we are doing a normal write to a database file (as opposed to - ** doing a hot-journal rollback or a write to some file other than a - ** normal database file) and we truncate the file to zero length, - ** that effectively updates the change counter. This might happen - ** when restoring a database using the backup API from a zero-length - ** source. - */ - if( pFile->inNormalWrite && nByte==0 ){ - pFile->transCntrChng = 1; - } -#endif - -#if SQLITE_MAX_MMAP_SIZE>0 - /* If the file was just truncated to a size smaller than the currently - ** mapped region, reduce the effective mapping size as well. SQLite will - ** use read() and write() to access data beyond this point from now on. - */ - if( nByte<pFile->mmapSize ){ - pFile->mmapSize = nByte; - } -#endif - - return SQLITE_OK; - } -} - -/* -** Determine the current size of a file in bytes -*/ -static int unixFileSize(sqlite3_file *id, i64 *pSize){ - int rc; - struct stat buf; - assert( id ); - rc = osFstat(((unixFile*)id)->h, &buf); - SimulateIOError( rc=1 ); - if( rc!=0 ){ - storeLastErrno((unixFile*)id, errno); - return SQLITE_IOERR_FSTAT; - } - *pSize = buf.st_size; - - /* When opening a zero-size database, the findInodeInfo() procedure - ** writes a single byte into that file in order to work around a bug - ** in the OS-X msdos filesystem. In order to avoid problems with upper - ** layers, we need to report this file size as zero even though it is - ** really 1. Ticket #3260. - */ - if( *pSize==1 ) *pSize = 0; - - - return SQLITE_OK; -} - -#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) -/* -** Handler for proxy-locking file-control verbs. Defined below in the -** proxying locking division. -*/ -static int proxyFileControl(sqlite3_file*,int,void*); -#endif - -/* -** This function is called to handle the SQLITE_FCNTL_SIZE_HINT -** file-control operation. Enlarge the database to nBytes in size -** (rounded up to the next chunk-size). If the database is already -** nBytes or larger, this routine is a no-op. -*/ -static int fcntlSizeHint(unixFile *pFile, i64 nByte){ - if( pFile->szChunk>0 ){ - i64 nSize; /* Required file size */ - struct stat buf; /* Used to hold return values of fstat() */ - - if( osFstat(pFile->h, &buf) ){ - return SQLITE_IOERR_FSTAT; - } - - nSize = ((nByte+pFile->szChunk-1) / pFile->szChunk) * pFile->szChunk; - if( nSize>(i64)buf.st_size ){ - -#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE - /* The code below is handling the return value of osFallocate() - ** correctly. posix_fallocate() is defined to "returns zero on success, - ** or an error number on failure". See the manpage for details. */ - int err; - do{ - err = osFallocate(pFile->h, buf.st_size, nSize-buf.st_size); - }while( err==EINTR ); - if( err ) return SQLITE_IOERR_WRITE; -#else - /* If the OS does not have posix_fallocate(), fake it. Write a - ** single byte to the last byte in each block that falls entirely - ** within the extended region. Then, if required, a single byte - ** at offset (nSize-1), to set the size of the file correctly. - ** This is a similar technique to that used by glibc on systems - ** that do not have a real fallocate() call. - */ - int nBlk = buf.st_blksize; /* File-system block size */ - int nWrite = 0; /* Number of bytes written by seekAndWrite */ - i64 iWrite; /* Next offset to write to */ - - iWrite = ((buf.st_size + 2*nBlk - 1)/nBlk)*nBlk-1; - assert( iWrite>=buf.st_size ); - assert( (iWrite/nBlk)==((buf.st_size+nBlk-1)/nBlk) ); - assert( ((iWrite+1)%nBlk)==0 ); - for(/*no-op*/; iWrite<nSize; iWrite+=nBlk ){ - nWrite = seekAndWrite(pFile, iWrite, "", 1); - if( nWrite!=1 ) return SQLITE_IOERR_WRITE; - } - if( nWrite==0 || (nSize%nBlk) ){ - nWrite = seekAndWrite(pFile, nSize-1, "", 1); - if( nWrite!=1 ) return SQLITE_IOERR_WRITE; - } -#endif - } - } - -#if SQLITE_MAX_MMAP_SIZE>0 - if( pFile->mmapSizeMax>0 && nByte>pFile->mmapSize ){ - int rc; - if( pFile->szChunk<=0 ){ - if( robust_ftruncate(pFile->h, nByte) ){ - storeLastErrno(pFile, errno); - return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath); - } - } - - rc = unixMapfile(pFile, nByte); - return rc; - } -#endif - - return SQLITE_OK; -} - -/* -** If *pArg is initially negative then this is a query. Set *pArg to -** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set. -** -** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags. -*/ -static void unixModeBit(unixFile *pFile, unsigned char mask, int *pArg){ - if( *pArg<0 ){ - *pArg = (pFile->ctrlFlags & mask)!=0; - }else if( (*pArg)==0 ){ - pFile->ctrlFlags &= ~mask; - }else{ - pFile->ctrlFlags |= mask; - } -} - -/* Forward declaration */ -static int unixGetTempname(int nBuf, char *zBuf); - -/* -** Information and control of an open file handle. -*/ -static int unixFileControl(sqlite3_file *id, int op, void *pArg){ - unixFile *pFile = (unixFile*)id; - switch( op ){ - case SQLITE_FCNTL_WAL_BLOCK: { - /* pFile->ctrlFlags |= UNIXFILE_BLOCK; // Deferred feature */ - return SQLITE_OK; - } - case SQLITE_FCNTL_LOCKSTATE: { - *(int*)pArg = pFile->eFileLock; - return SQLITE_OK; - } - case SQLITE_FCNTL_LAST_ERRNO: { - *(int*)pArg = pFile->lastErrno; - return SQLITE_OK; - } - case SQLITE_FCNTL_CHUNK_SIZE: { - pFile->szChunk = *(int *)pArg; - return SQLITE_OK; - } - case SQLITE_FCNTL_SIZE_HINT: { - int rc; - SimulateIOErrorBenign(1); - rc = fcntlSizeHint(pFile, *(i64 *)pArg); - SimulateIOErrorBenign(0); - return rc; - } - case SQLITE_FCNTL_PERSIST_WAL: { - unixModeBit(pFile, UNIXFILE_PERSIST_WAL, (int*)pArg); - return SQLITE_OK; - } - case SQLITE_FCNTL_POWERSAFE_OVERWRITE: { - unixModeBit(pFile, UNIXFILE_PSOW, (int*)pArg); - return SQLITE_OK; - } - case SQLITE_FCNTL_VFSNAME: { - *(char**)pArg = sqlite3_mprintf("%s", pFile->pVfs->zName); - return SQLITE_OK; - } - case SQLITE_FCNTL_TEMPFILENAME: { - char *zTFile = sqlite3_malloc64( pFile->pVfs->mxPathname ); - if( zTFile ){ - unixGetTempname(pFile->pVfs->mxPathname, zTFile); - *(char**)pArg = zTFile; - } - return SQLITE_OK; - } - case SQLITE_FCNTL_HAS_MOVED: { - *(int*)pArg = fileHasMoved(pFile); - return SQLITE_OK; - } -#if SQLITE_MAX_MMAP_SIZE>0 - case SQLITE_FCNTL_MMAP_SIZE: { - i64 newLimit = *(i64*)pArg; - int rc = SQLITE_OK; - if( newLimit>sqlite3GlobalConfig.mxMmap ){ - newLimit = sqlite3GlobalConfig.mxMmap; - } - *(i64*)pArg = pFile->mmapSizeMax; - if( newLimit>=0 && newLimit!=pFile->mmapSizeMax && pFile->nFetchOut==0 ){ - pFile->mmapSizeMax = newLimit; - if( pFile->mmapSize>0 ){ - unixUnmapfile(pFile); - rc = unixMapfile(pFile, -1); - } - } - return rc; - } -#endif -#ifdef SQLITE_DEBUG - /* The pager calls this method to signal that it has done - ** a rollback and that the database is therefore unchanged and - ** it hence it is OK for the transaction change counter to be - ** unchanged. - */ - case SQLITE_FCNTL_DB_UNCHANGED: { - ((unixFile*)id)->dbUpdate = 0; - return SQLITE_OK; - } -#endif -#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) - case SQLITE_FCNTL_SET_LOCKPROXYFILE: - case SQLITE_FCNTL_GET_LOCKPROXYFILE: { - return proxyFileControl(id,op,pArg); - } -#endif /* SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) */ - } - return SQLITE_NOTFOUND; -} - -/* -** Return the sector size in bytes of the underlying block device for -** the specified file. This is almost always 512 bytes, but may be -** larger for some devices. -** -** SQLite code assumes this function cannot fail. It also assumes that -** if two files are created in the same file-system directory (i.e. -** a database and its journal file) that the sector size will be the -** same for both. -*/ -#ifndef __QNXNTO__ -static int unixSectorSize(sqlite3_file *NotUsed){ - UNUSED_PARAMETER(NotUsed); - return SQLITE_DEFAULT_SECTOR_SIZE; -} -#endif - -/* -** The following version of unixSectorSize() is optimized for QNX. -*/ -#ifdef __QNXNTO__ -#include <sys/dcmd_blk.h> -#include <sys/statvfs.h> -static int unixSectorSize(sqlite3_file *id){ - unixFile *pFile = (unixFile*)id; - if( pFile->sectorSize == 0 ){ - struct statvfs fsInfo; - - /* Set defaults for non-supported filesystems */ - pFile->sectorSize = SQLITE_DEFAULT_SECTOR_SIZE; - pFile->deviceCharacteristics = 0; - if( fstatvfs(pFile->h, &fsInfo) == -1 ) { - return pFile->sectorSize; - } - - if( !strcmp(fsInfo.f_basetype, "tmp") ) { - pFile->sectorSize = fsInfo.f_bsize; - pFile->deviceCharacteristics = - SQLITE_IOCAP_ATOMIC4K | /* All ram filesystem writes are atomic */ - SQLITE_IOCAP_SAFE_APPEND | /* growing the file does not occur until - ** the write succeeds */ - SQLITE_IOCAP_SEQUENTIAL | /* The ram filesystem has no write behind - ** so it is ordered */ - 0; - }else if( strstr(fsInfo.f_basetype, "etfs") ){ - pFile->sectorSize = fsInfo.f_bsize; - pFile->deviceCharacteristics = - /* etfs cluster size writes are atomic */ - (pFile->sectorSize / 512 * SQLITE_IOCAP_ATOMIC512) | - SQLITE_IOCAP_SAFE_APPEND | /* growing the file does not occur until - ** the write succeeds */ - SQLITE_IOCAP_SEQUENTIAL | /* The ram filesystem has no write behind - ** so it is ordered */ - 0; - }else if( !strcmp(fsInfo.f_basetype, "qnx6") ){ - pFile->sectorSize = fsInfo.f_bsize; - pFile->deviceCharacteristics = - SQLITE_IOCAP_ATOMIC | /* All filesystem writes are atomic */ - SQLITE_IOCAP_SAFE_APPEND | /* growing the file does not occur until - ** the write succeeds */ - SQLITE_IOCAP_SEQUENTIAL | /* The ram filesystem has no write behind - ** so it is ordered */ - 0; - }else if( !strcmp(fsInfo.f_basetype, "qnx4") ){ - pFile->sectorSize = fsInfo.f_bsize; - pFile->deviceCharacteristics = - /* full bitset of atomics from max sector size and smaller */ - ((pFile->sectorSize / 512 * SQLITE_IOCAP_ATOMIC512) << 1) - 2 | - SQLITE_IOCAP_SEQUENTIAL | /* The ram filesystem has no write behind - ** so it is ordered */ - 0; - }else if( strstr(fsInfo.f_basetype, "dos") ){ - pFile->sectorSize = fsInfo.f_bsize; - pFile->deviceCharacteristics = - /* full bitset of atomics from max sector size and smaller */ - ((pFile->sectorSize / 512 * SQLITE_IOCAP_ATOMIC512) << 1) - 2 | - SQLITE_IOCAP_SEQUENTIAL | /* The ram filesystem has no write behind - ** so it is ordered */ - 0; - }else{ - pFile->deviceCharacteristics = - SQLITE_IOCAP_ATOMIC512 | /* blocks are atomic */ - SQLITE_IOCAP_SAFE_APPEND | /* growing the file does not occur until - ** the write succeeds */ - 0; - } - } - /* Last chance verification. If the sector size isn't a multiple of 512 - ** then it isn't valid.*/ - if( pFile->sectorSize % 512 != 0 ){ - pFile->deviceCharacteristics = 0; - pFile->sectorSize = SQLITE_DEFAULT_SECTOR_SIZE; - } - return pFile->sectorSize; -} -#endif /* __QNXNTO__ */ - -/* -** Return the device characteristics for the file. -** -** This VFS is set up to return SQLITE_IOCAP_POWERSAFE_OVERWRITE by default. -** However, that choice is controversial since technically the underlying -** file system does not always provide powersafe overwrites. (In other -** words, after a power-loss event, parts of the file that were never -** written might end up being altered.) However, non-PSOW behavior is very, -** very rare. And asserting PSOW makes a large reduction in the amount -** of required I/O for journaling, since a lot of padding is eliminated. -** Hence, while POWERSAFE_OVERWRITE is on by default, there is a file-control -** available to turn it off and URI query parameter available to turn it off. -*/ -static int unixDeviceCharacteristics(sqlite3_file *id){ - unixFile *p = (unixFile*)id; - int rc = 0; -#ifdef __QNXNTO__ - if( p->sectorSize==0 ) unixSectorSize(id); - rc = p->deviceCharacteristics; -#endif - if( p->ctrlFlags & UNIXFILE_PSOW ){ - rc |= SQLITE_IOCAP_POWERSAFE_OVERWRITE; - } - return rc; -} - -#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0 - -/* -** Return the system page size. -** -** This function should not be called directly by other code in this file. -** Instead, it should be called via macro osGetpagesize(). -*/ -static int unixGetpagesize(void){ -#if OS_VXWORKS - return 1024; -#elif defined(_BSD_SOURCE) - return getpagesize(); -#else - return (int)sysconf(_SC_PAGESIZE); -#endif -} - -#endif /* !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0 */ - -#ifndef SQLITE_OMIT_WAL - -/* -** Object used to represent an shared memory buffer. -** -** When multiple threads all reference the same wal-index, each thread -** has its own unixShm object, but they all point to a single instance -** of this unixShmNode object. In other words, each wal-index is opened -** only once per process. -** -** Each unixShmNode object is connected to a single unixInodeInfo object. -** We could coalesce this object into unixInodeInfo, but that would mean -** every open file that does not use shared memory (in other words, most -** open files) would have to carry around this extra information. So -** the unixInodeInfo object contains a pointer to this unixShmNode object -** and the unixShmNode object is created only when needed. -** -** unixMutexHeld() must be true when creating or destroying -** this object or while reading or writing the following fields: -** -** nRef -** -** The following fields are read-only after the object is created: -** -** fid -** zFilename -** -** Either unixShmNode.mutex must be held or unixShmNode.nRef==0 and -** unixMutexHeld() is true when reading or writing any other field -** in this structure. -*/ -struct unixShmNode { - unixInodeInfo *pInode; /* unixInodeInfo that owns this SHM node */ - sqlite3_mutex *mutex; /* Mutex to access this object */ - char *zFilename; /* Name of the mmapped file */ - int h; /* Open file descriptor */ - int szRegion; /* Size of shared-memory regions */ - u16 nRegion; /* Size of array apRegion */ - u8 isReadonly; /* True if read-only */ - char **apRegion; /* Array of mapped shared-memory regions */ - int nRef; /* Number of unixShm objects pointing to this */ - unixShm *pFirst; /* All unixShm objects pointing to this */ -#ifdef SQLITE_DEBUG - u8 exclMask; /* Mask of exclusive locks held */ - u8 sharedMask; /* Mask of shared locks held */ - u8 nextShmId; /* Next available unixShm.id value */ -#endif -}; - -/* -** Structure used internally by this VFS to record the state of an -** open shared memory connection. -** -** The following fields are initialized when this object is created and -** are read-only thereafter: -** -** unixShm.pFile -** unixShm.id -** -** All other fields are read/write. The unixShm.pFile->mutex must be held -** while accessing any read/write fields. -*/ -struct unixShm { - unixShmNode *pShmNode; /* The underlying unixShmNode object */ - unixShm *pNext; /* Next unixShm with the same unixShmNode */ - u8 hasMutex; /* True if holding the unixShmNode mutex */ - u8 id; /* Id of this connection within its unixShmNode */ - u16 sharedMask; /* Mask of shared locks held */ - u16 exclMask; /* Mask of exclusive locks held */ -}; - -/* -** Constants used for locking -*/ -#define UNIX_SHM_BASE ((22+SQLITE_SHM_NLOCK)*4) /* first lock byte */ -#define UNIX_SHM_DMS (UNIX_SHM_BASE+SQLITE_SHM_NLOCK) /* deadman switch */ - -/* -** Apply posix advisory locks for all bytes from ofst through ofst+n-1. -** -** Locks block if the mask is exactly UNIX_SHM_C and are non-blocking -** otherwise. -*/ -static int unixShmSystemLock( - unixFile *pFile, /* Open connection to the WAL file */ - int lockType, /* F_UNLCK, F_RDLCK, or F_WRLCK */ - int ofst, /* First byte of the locking range */ - int n /* Number of bytes to lock */ -){ - unixShmNode *pShmNode; /* Apply locks to this open shared-memory segment */ - struct flock f; /* The posix advisory locking structure */ - int rc = SQLITE_OK; /* Result code form fcntl() */ - - /* Access to the unixShmNode object is serialized by the caller */ - pShmNode = pFile->pInode->pShmNode; - assert( sqlite3_mutex_held(pShmNode->mutex) || pShmNode->nRef==0 ); - - /* Shared locks never span more than one byte */ - assert( n==1 || lockType!=F_RDLCK ); - - /* Locks are within range */ - assert( n>=1 && n<SQLITE_SHM_NLOCK ); - - if( pShmNode->h>=0 ){ - int lkType; - /* Initialize the locking parameters */ - memset(&f, 0, sizeof(f)); - f.l_type = lockType; - f.l_whence = SEEK_SET; - f.l_start = ofst; - f.l_len = n; - - lkType = (pFile->ctrlFlags & UNIXFILE_BLOCK)!=0 ? F_SETLKW : F_SETLK; - rc = osFcntl(pShmNode->h, lkType, &f); - rc = (rc!=(-1)) ? SQLITE_OK : SQLITE_BUSY; - pFile->ctrlFlags &= ~UNIXFILE_BLOCK; - } - - /* Update the global lock state and do debug tracing */ -#ifdef SQLITE_DEBUG - { u16 mask; - OSTRACE(("SHM-LOCK ")); - mask = ofst>31 ? 0xffff : (1<<(ofst+n)) - (1<<ofst); - if( rc==SQLITE_OK ){ - if( lockType==F_UNLCK ){ - OSTRACE(("unlock %d ok", ofst)); - pShmNode->exclMask &= ~mask; - pShmNode->sharedMask &= ~mask; - }else if( lockType==F_RDLCK ){ - OSTRACE(("read-lock %d ok", ofst)); - pShmNode->exclMask &= ~mask; - pShmNode->sharedMask |= mask; - }else{ - assert( lockType==F_WRLCK ); - OSTRACE(("write-lock %d ok", ofst)); - pShmNode->exclMask |= mask; - pShmNode->sharedMask &= ~mask; - } - }else{ - if( lockType==F_UNLCK ){ - OSTRACE(("unlock %d failed", ofst)); - }else if( lockType==F_RDLCK ){ - OSTRACE(("read-lock failed")); - }else{ - assert( lockType==F_WRLCK ); - OSTRACE(("write-lock %d failed", ofst)); - } - } - OSTRACE((" - afterwards %03x,%03x\n", - pShmNode->sharedMask, pShmNode->exclMask)); - } -#endif - - return rc; -} - -/* -** Return the minimum number of 32KB shm regions that should be mapped at -** a time, assuming that each mapping must be an integer multiple of the -** current system page-size. -** -** Usually, this is 1. The exception seems to be systems that are configured -** to use 64KB pages - in this case each mapping must cover at least two -** shm regions. -*/ -static int unixShmRegionPerMap(void){ - int shmsz = 32*1024; /* SHM region size */ - int pgsz = osGetpagesize(); /* System page size */ - assert( ((pgsz-1)&pgsz)==0 ); /* Page size must be a power of 2 */ - if( pgsz<shmsz ) return 1; - return pgsz/shmsz; -} - -/* -** Purge the unixShmNodeList list of all entries with unixShmNode.nRef==0. -** -** This is not a VFS shared-memory method; it is a utility function called -** by VFS shared-memory methods. -*/ -static void unixShmPurge(unixFile *pFd){ - unixShmNode *p = pFd->pInode->pShmNode; - assert( unixMutexHeld() ); - if( p && p->nRef==0 ){ - int nShmPerMap = unixShmRegionPerMap(); - int i; - assert( p->pInode==pFd->pInode ); - sqlite3_mutex_free(p->mutex); - for(i=0; i<p->nRegion; i+=nShmPerMap){ - if( p->h>=0 ){ - osMunmap(p->apRegion[i], p->szRegion); - }else{ - sqlite3_free(p->apRegion[i]); - } - } - sqlite3_free(p->apRegion); - if( p->h>=0 ){ - robust_close(pFd, p->h, __LINE__); - p->h = -1; - } - p->pInode->pShmNode = 0; - sqlite3_free(p); - } -} - -/* -** Open a shared-memory area associated with open database file pDbFd. -** This particular implementation uses mmapped files. -** -** The file used to implement shared-memory is in the same directory -** as the open database file and has the same name as the open database -** file with the "-shm" suffix added. For example, if the database file -** is "/home/user1/config.db" then the file that is created and mmapped -** for shared memory will be called "/home/user1/config.db-shm". -** -** Another approach to is to use files in /dev/shm or /dev/tmp or an -** some other tmpfs mount. But if a file in a different directory -** from the database file is used, then differing access permissions -** or a chroot() might cause two different processes on the same -** database to end up using different files for shared memory - -** meaning that their memory would not really be shared - resulting -** in database corruption. Nevertheless, this tmpfs file usage -** can be enabled at compile-time using -DSQLITE_SHM_DIRECTORY="/dev/shm" -** or the equivalent. The use of the SQLITE_SHM_DIRECTORY compile-time -** option results in an incompatible build of SQLite; builds of SQLite -** that with differing SQLITE_SHM_DIRECTORY settings attempt to use the -** same database file at the same time, database corruption will likely -** result. The SQLITE_SHM_DIRECTORY compile-time option is considered -** "unsupported" and may go away in a future SQLite release. -** -** When opening a new shared-memory file, if no other instances of that -** file are currently open, in this process or in other processes, then -** the file must be truncated to zero length or have its header cleared. -** -** If the original database file (pDbFd) is using the "unix-excl" VFS -** that means that an exclusive lock is held on the database file and -** that no other processes are able to read or write the database. In -** that case, we do not really need shared memory. No shared memory -** file is created. The shared memory will be simulated with heap memory. -*/ -static int unixOpenSharedMemory(unixFile *pDbFd){ - struct unixShm *p = 0; /* The connection to be opened */ - struct unixShmNode *pShmNode; /* The underlying mmapped file */ - int rc; /* Result code */ - unixInodeInfo *pInode; /* The inode of fd */ - char *zShmFilename; /* Name of the file used for SHM */ - int nShmFilename; /* Size of the SHM filename in bytes */ - - /* Allocate space for the new unixShm object. */ - p = sqlite3_malloc64( sizeof(*p) ); - if( p==0 ) return SQLITE_NOMEM; - memset(p, 0, sizeof(*p)); - assert( pDbFd->pShm==0 ); - - /* Check to see if a unixShmNode object already exists. Reuse an existing - ** one if present. Create a new one if necessary. - */ - unixEnterMutex(); - pInode = pDbFd->pInode; - pShmNode = pInode->pShmNode; - if( pShmNode==0 ){ - struct stat sStat; /* fstat() info for database file */ -#ifndef SQLITE_SHM_DIRECTORY - const char *zBasePath = pDbFd->zPath; -#endif - - /* Call fstat() to figure out the permissions on the database file. If - ** a new *-shm file is created, an attempt will be made to create it - ** with the same permissions. - */ - if( osFstat(pDbFd->h, &sStat) && pInode->bProcessLock==0 ){ - rc = SQLITE_IOERR_FSTAT; - goto shm_open_err; - } - -#ifdef SQLITE_SHM_DIRECTORY - nShmFilename = sizeof(SQLITE_SHM_DIRECTORY) + 31; -#else - nShmFilename = 6 + (int)strlen(zBasePath); -#endif - pShmNode = sqlite3_malloc64( sizeof(*pShmNode) + nShmFilename ); - if( pShmNode==0 ){ - rc = SQLITE_NOMEM; - goto shm_open_err; - } - memset(pShmNode, 0, sizeof(*pShmNode)+nShmFilename); - zShmFilename = pShmNode->zFilename = (char*)&pShmNode[1]; -#ifdef SQLITE_SHM_DIRECTORY - sqlite3_snprintf(nShmFilename, zShmFilename, - SQLITE_SHM_DIRECTORY "/sqlite-shm-%x-%x", - (u32)sStat.st_ino, (u32)sStat.st_dev); -#else - sqlite3_snprintf(nShmFilename, zShmFilename, "%s-shm", zBasePath); - sqlite3FileSuffix3(pDbFd->zPath, zShmFilename); -#endif - pShmNode->h = -1; - pDbFd->pInode->pShmNode = pShmNode; - pShmNode->pInode = pDbFd->pInode; - pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST); - if( pShmNode->mutex==0 ){ - rc = SQLITE_NOMEM; - goto shm_open_err; - } - - if( pInode->bProcessLock==0 ){ - int openFlags = O_RDWR | O_CREAT; - if( sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0) ){ - openFlags = O_RDONLY; - pShmNode->isReadonly = 1; - } - pShmNode->h = robust_open(zShmFilename, openFlags, (sStat.st_mode&0777)); - if( pShmNode->h<0 ){ - rc = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zShmFilename); - goto shm_open_err; - } - - /* If this process is running as root, make sure that the SHM file - ** is owned by the same user that owns the original database. Otherwise, - ** the original owner will not be able to connect. - */ - osFchown(pShmNode->h, sStat.st_uid, sStat.st_gid); - - /* Check to see if another process is holding the dead-man switch. - ** If not, truncate the file to zero length. - */ - rc = SQLITE_OK; - if( unixShmSystemLock(pDbFd, F_WRLCK, UNIX_SHM_DMS, 1)==SQLITE_OK ){ - if( robust_ftruncate(pShmNode->h, 0) ){ - rc = unixLogError(SQLITE_IOERR_SHMOPEN, "ftruncate", zShmFilename); - } - } - if( rc==SQLITE_OK ){ - rc = unixShmSystemLock(pDbFd, F_RDLCK, UNIX_SHM_DMS, 1); - } - if( rc ) goto shm_open_err; - } - } - - /* Make the new connection a child of the unixShmNode */ - p->pShmNode = pShmNode; -#ifdef SQLITE_DEBUG - p->id = pShmNode->nextShmId++; -#endif - pShmNode->nRef++; - pDbFd->pShm = p; - unixLeaveMutex(); - - /* The reference count on pShmNode has already been incremented under - ** the cover of the unixEnterMutex() mutex and the pointer from the - ** new (struct unixShm) object to the pShmNode has been set. All that is - ** left to do is to link the new object into the linked list starting - ** at pShmNode->pFirst. This must be done while holding the pShmNode->mutex - ** mutex. - */ - sqlite3_mutex_enter(pShmNode->mutex); - p->pNext = pShmNode->pFirst; - pShmNode->pFirst = p; - sqlite3_mutex_leave(pShmNode->mutex); - return SQLITE_OK; - - /* Jump here on any error */ -shm_open_err: - unixShmPurge(pDbFd); /* This call frees pShmNode if required */ - sqlite3_free(p); - unixLeaveMutex(); - return rc; -} - -/* -** This function is called to obtain a pointer to region iRegion of the -** shared-memory associated with the database file fd. Shared-memory regions -** are numbered starting from zero. Each shared-memory region is szRegion -** bytes in size. -** -** If an error occurs, an error code is returned and *pp is set to NULL. -** -** Otherwise, if the bExtend parameter is 0 and the requested shared-memory -** region has not been allocated (by any client, including one running in a -** separate process), then *pp is set to NULL and SQLITE_OK returned. If -** bExtend is non-zero and the requested shared-memory region has not yet -** been allocated, it is allocated by this function. -** -** If the shared-memory region has already been allocated or is allocated by -** this call as described above, then it is mapped into this processes -** address space (if it is not already), *pp is set to point to the mapped -** memory and SQLITE_OK returned. -*/ -static int unixShmMap( - sqlite3_file *fd, /* Handle open on database file */ - int iRegion, /* Region to retrieve */ - int szRegion, /* Size of regions */ - int bExtend, /* True to extend file if necessary */ - void volatile **pp /* OUT: Mapped memory */ -){ - unixFile *pDbFd = (unixFile*)fd; - unixShm *p; - unixShmNode *pShmNode; - int rc = SQLITE_OK; - int nShmPerMap = unixShmRegionPerMap(); - int nReqRegion; - - /* If the shared-memory file has not yet been opened, open it now. */ - if( pDbFd->pShm==0 ){ - rc = unixOpenSharedMemory(pDbFd); - if( rc!=SQLITE_OK ) return rc; - } - - p = pDbFd->pShm; - pShmNode = p->pShmNode; - sqlite3_mutex_enter(pShmNode->mutex); - assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 ); - assert( pShmNode->pInode==pDbFd->pInode ); - assert( pShmNode->h>=0 || pDbFd->pInode->bProcessLock==1 ); - assert( pShmNode->h<0 || pDbFd->pInode->bProcessLock==0 ); - - /* Minimum number of regions required to be mapped. */ - nReqRegion = ((iRegion+nShmPerMap) / nShmPerMap) * nShmPerMap; - - if( pShmNode->nRegion<nReqRegion ){ - char **apNew; /* New apRegion[] array */ - int nByte = nReqRegion*szRegion; /* Minimum required file size */ - struct stat sStat; /* Used by fstat() */ - - pShmNode->szRegion = szRegion; - - if( pShmNode->h>=0 ){ - /* The requested region is not mapped into this processes address space. - ** Check to see if it has been allocated (i.e. if the wal-index file is - ** large enough to contain the requested region). - */ - if( osFstat(pShmNode->h, &sStat) ){ - rc = SQLITE_IOERR_SHMSIZE; - goto shmpage_out; - } - - if( sStat.st_size<nByte ){ - /* The requested memory region does not exist. If bExtend is set to - ** false, exit early. *pp will be set to NULL and SQLITE_OK returned. - */ - if( !bExtend ){ - goto shmpage_out; - } - - /* Alternatively, if bExtend is true, extend the file. Do this by - ** writing a single byte to the end of each (OS) page being - ** allocated or extended. Technically, we need only write to the - ** last page in order to extend the file. But writing to all new - ** pages forces the OS to allocate them immediately, which reduces - ** the chances of SIGBUS while accessing the mapped region later on. - */ - else{ - static const int pgsz = 4096; - int iPg; - - /* Write to the last byte of each newly allocated or extended page */ - assert( (nByte % pgsz)==0 ); - for(iPg=(sStat.st_size/pgsz); iPg<(nByte/pgsz); iPg++){ - if( seekAndWriteFd(pShmNode->h, iPg*pgsz + pgsz-1, "", 1, 0)!=1 ){ - const char *zFile = pShmNode->zFilename; - rc = unixLogError(SQLITE_IOERR_SHMSIZE, "write", zFile); - goto shmpage_out; - } - } - } - } - } - - /* Map the requested memory region into this processes address space. */ - apNew = (char **)sqlite3_realloc( - pShmNode->apRegion, nReqRegion*sizeof(char *) - ); - if( !apNew ){ - rc = SQLITE_IOERR_NOMEM; - goto shmpage_out; - } - pShmNode->apRegion = apNew; - while( pShmNode->nRegion<nReqRegion ){ - int nMap = szRegion*nShmPerMap; - int i; - void *pMem; - if( pShmNode->h>=0 ){ - pMem = osMmap(0, nMap, - pShmNode->isReadonly ? PROT_READ : PROT_READ|PROT_WRITE, - MAP_SHARED, pShmNode->h, szRegion*(i64)pShmNode->nRegion - ); - if( pMem==MAP_FAILED ){ - rc = unixLogError(SQLITE_IOERR_SHMMAP, "mmap", pShmNode->zFilename); - goto shmpage_out; - } - }else{ - pMem = sqlite3_malloc64(szRegion); - if( pMem==0 ){ - rc = SQLITE_NOMEM; - goto shmpage_out; - } - memset(pMem, 0, szRegion); - } - - for(i=0; i<nShmPerMap; i++){ - pShmNode->apRegion[pShmNode->nRegion+i] = &((char*)pMem)[szRegion*i]; - } - pShmNode->nRegion += nShmPerMap; - } - } - -shmpage_out: - if( pShmNode->nRegion>iRegion ){ - *pp = pShmNode->apRegion[iRegion]; - }else{ - *pp = 0; - } - if( pShmNode->isReadonly && rc==SQLITE_OK ) rc = SQLITE_READONLY; - sqlite3_mutex_leave(pShmNode->mutex); - return rc; -} - -/* -** Change the lock state for a shared-memory segment. -** -** Note that the relationship between SHAREd and EXCLUSIVE locks is a little -** different here than in posix. In xShmLock(), one can go from unlocked -** to shared and back or from unlocked to exclusive and back. But one may -** not go from shared to exclusive or from exclusive to shared. -*/ -static int unixShmLock( - sqlite3_file *fd, /* Database file holding the shared memory */ - int ofst, /* First lock to acquire or release */ - int n, /* Number of locks to acquire or release */ - int flags /* What to do with the lock */ -){ - unixFile *pDbFd = (unixFile*)fd; /* Connection holding shared memory */ - unixShm *p = pDbFd->pShm; /* The shared memory being locked */ - unixShm *pX; /* For looping over all siblings */ - unixShmNode *pShmNode = p->pShmNode; /* The underlying file iNode */ - int rc = SQLITE_OK; /* Result code */ - u16 mask; /* Mask of locks to take or release */ - - assert( pShmNode==pDbFd->pInode->pShmNode ); - assert( pShmNode->pInode==pDbFd->pInode ); - assert( ofst>=0 && ofst+n<=SQLITE_SHM_NLOCK ); - assert( n>=1 ); - assert( flags==(SQLITE_SHM_LOCK | SQLITE_SHM_SHARED) - || flags==(SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE) - || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED) - || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE) ); - assert( n==1 || (flags & SQLITE_SHM_EXCLUSIVE)!=0 ); - assert( pShmNode->h>=0 || pDbFd->pInode->bProcessLock==1 ); - assert( pShmNode->h<0 || pDbFd->pInode->bProcessLock==0 ); - - mask = (1<<(ofst+n)) - (1<<ofst); - assert( n>1 || mask==(1<<ofst) ); - sqlite3_mutex_enter(pShmNode->mutex); - if( flags & SQLITE_SHM_UNLOCK ){ - u16 allMask = 0; /* Mask of locks held by siblings */ - - /* See if any siblings hold this same lock */ - for(pX=pShmNode->pFirst; pX; pX=pX->pNext){ - if( pX==p ) continue; - assert( (pX->exclMask & (p->exclMask|p->sharedMask))==0 ); - allMask |= pX->sharedMask; - } - - /* Unlock the system-level locks */ - if( (mask & allMask)==0 ){ - rc = unixShmSystemLock(pDbFd, F_UNLCK, ofst+UNIX_SHM_BASE, n); - }else{ - rc = SQLITE_OK; - } - - /* Undo the local locks */ - if( rc==SQLITE_OK ){ - p->exclMask &= ~mask; - p->sharedMask &= ~mask; - } - }else if( flags & SQLITE_SHM_SHARED ){ - u16 allShared = 0; /* Union of locks held by connections other than "p" */ - - /* Find out which shared locks are already held by sibling connections. - ** If any sibling already holds an exclusive lock, go ahead and return - ** SQLITE_BUSY. - */ - for(pX=pShmNode->pFirst; pX; pX=pX->pNext){ - if( (pX->exclMask & mask)!=0 ){ - rc = SQLITE_BUSY; - break; - } - allShared |= pX->sharedMask; - } - - /* Get shared locks at the system level, if necessary */ - if( rc==SQLITE_OK ){ - if( (allShared & mask)==0 ){ - rc = unixShmSystemLock(pDbFd, F_RDLCK, ofst+UNIX_SHM_BASE, n); - }else{ - rc = SQLITE_OK; - } - } - - /* Get the local shared locks */ - if( rc==SQLITE_OK ){ - p->sharedMask |= mask; - } - }else{ - /* Make sure no sibling connections hold locks that will block this - ** lock. If any do, return SQLITE_BUSY right away. - */ - for(pX=pShmNode->pFirst; pX; pX=pX->pNext){ - if( (pX->exclMask & mask)!=0 || (pX->sharedMask & mask)!=0 ){ - rc = SQLITE_BUSY; - break; - } - } - - /* Get the exclusive locks at the system level. Then if successful - ** also mark the local connection as being locked. - */ - if( rc==SQLITE_OK ){ - rc = unixShmSystemLock(pDbFd, F_WRLCK, ofst+UNIX_SHM_BASE, n); - if( rc==SQLITE_OK ){ - assert( (p->sharedMask & mask)==0 ); - p->exclMask |= mask; - } - } - } - sqlite3_mutex_leave(pShmNode->mutex); - OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %03x,%03x\n", - p->id, osGetpid(0), p->sharedMask, p->exclMask)); - return rc; -} - -/* -** Implement a memory barrier or memory fence on shared memory. -** -** All loads and stores begun before the barrier must complete before -** any load or store begun after the barrier. -*/ -static void unixShmBarrier( - sqlite3_file *fd /* Database file holding the shared memory */ -){ - UNUSED_PARAMETER(fd); - sqlite3MemoryBarrier(); /* compiler-defined memory barrier */ - unixEnterMutex(); /* Also mutex, for redundancy */ - unixLeaveMutex(); -} - -/* -** Close a connection to shared-memory. Delete the underlying -** storage if deleteFlag is true. -** -** If there is no shared memory associated with the connection then this -** routine is a harmless no-op. -*/ -static int unixShmUnmap( - sqlite3_file *fd, /* The underlying database file */ - int deleteFlag /* Delete shared-memory if true */ -){ - unixShm *p; /* The connection to be closed */ - unixShmNode *pShmNode; /* The underlying shared-memory file */ - unixShm **pp; /* For looping over sibling connections */ - unixFile *pDbFd; /* The underlying database file */ - - pDbFd = (unixFile*)fd; - p = pDbFd->pShm; - if( p==0 ) return SQLITE_OK; - pShmNode = p->pShmNode; - - assert( pShmNode==pDbFd->pInode->pShmNode ); - assert( pShmNode->pInode==pDbFd->pInode ); - - /* Remove connection p from the set of connections associated - ** with pShmNode */ - sqlite3_mutex_enter(pShmNode->mutex); - for(pp=&pShmNode->pFirst; (*pp)!=p; pp = &(*pp)->pNext){} - *pp = p->pNext; - - /* Free the connection p */ - sqlite3_free(p); - pDbFd->pShm = 0; - sqlite3_mutex_leave(pShmNode->mutex); - - /* If pShmNode->nRef has reached 0, then close the underlying - ** shared-memory file, too */ - unixEnterMutex(); - assert( pShmNode->nRef>0 ); - pShmNode->nRef--; - if( pShmNode->nRef==0 ){ - if( deleteFlag && pShmNode->h>=0 ){ - osUnlink(pShmNode->zFilename); - } - unixShmPurge(pDbFd); - } - unixLeaveMutex(); - - return SQLITE_OK; -} - - -#else -# define unixShmMap 0 -# define unixShmLock 0 -# define unixShmBarrier 0 -# define unixShmUnmap 0 -#endif /* #ifndef SQLITE_OMIT_WAL */ - -#if SQLITE_MAX_MMAP_SIZE>0 -/* -** If it is currently memory mapped, unmap file pFd. -*/ -static void unixUnmapfile(unixFile *pFd){ - assert( pFd->nFetchOut==0 ); - if( pFd->pMapRegion ){ - osMunmap(pFd->pMapRegion, pFd->mmapSizeActual); - pFd->pMapRegion = 0; - pFd->mmapSize = 0; - pFd->mmapSizeActual = 0; - } -} - -/* -** Attempt to set the size of the memory mapping maintained by file -** descriptor pFd to nNew bytes. Any existing mapping is discarded. -** -** If successful, this function sets the following variables: -** -** unixFile.pMapRegion -** unixFile.mmapSize -** unixFile.mmapSizeActual -** -** If unsuccessful, an error message is logged via sqlite3_log() and -** the three variables above are zeroed. In this case SQLite should -** continue accessing the database using the xRead() and xWrite() -** methods. -*/ -static void unixRemapfile( - unixFile *pFd, /* File descriptor object */ - i64 nNew /* Required mapping size */ -){ - const char *zErr = "mmap"; - int h = pFd->h; /* File descriptor open on db file */ - u8 *pOrig = (u8 *)pFd->pMapRegion; /* Pointer to current file mapping */ - i64 nOrig = pFd->mmapSizeActual; /* Size of pOrig region in bytes */ - u8 *pNew = 0; /* Location of new mapping */ - int flags = PROT_READ; /* Flags to pass to mmap() */ - - assert( pFd->nFetchOut==0 ); - assert( nNew>pFd->mmapSize ); - assert( nNew<=pFd->mmapSizeMax ); - assert( nNew>0 ); - assert( pFd->mmapSizeActual>=pFd->mmapSize ); - assert( MAP_FAILED!=0 ); - - if( (pFd->ctrlFlags & UNIXFILE_RDONLY)==0 ) flags |= PROT_WRITE; - - if( pOrig ){ -#if HAVE_MREMAP - i64 nReuse = pFd->mmapSize; -#else - const int szSyspage = osGetpagesize(); - i64 nReuse = (pFd->mmapSize & ~(szSyspage-1)); -#endif - u8 *pReq = &pOrig[nReuse]; - - /* Unmap any pages of the existing mapping that cannot be reused. */ - if( nReuse!=nOrig ){ - osMunmap(pReq, nOrig-nReuse); - } - -#if HAVE_MREMAP - pNew = osMremap(pOrig, nReuse, nNew, MREMAP_MAYMOVE); - zErr = "mremap"; -#else - pNew = osMmap(pReq, nNew-nReuse, flags, MAP_SHARED, h, nReuse); - if( pNew!=MAP_FAILED ){ - if( pNew!=pReq ){ - osMunmap(pNew, nNew - nReuse); - pNew = 0; - }else{ - pNew = pOrig; - } - } -#endif - - /* The attempt to extend the existing mapping failed. Free it. */ - if( pNew==MAP_FAILED || pNew==0 ){ - osMunmap(pOrig, nReuse); - } - } - - /* If pNew is still NULL, try to create an entirely new mapping. */ - if( pNew==0 ){ - pNew = osMmap(0, nNew, flags, MAP_SHARED, h, 0); - } - - if( pNew==MAP_FAILED ){ - pNew = 0; - nNew = 0; - unixLogError(SQLITE_OK, zErr, pFd->zPath); - - /* If the mmap() above failed, assume that all subsequent mmap() calls - ** will probably fail too. Fall back to using xRead/xWrite exclusively - ** in this case. */ - pFd->mmapSizeMax = 0; - } - pFd->pMapRegion = (void *)pNew; - pFd->mmapSize = pFd->mmapSizeActual = nNew; -} - -/* -** Memory map or remap the file opened by file-descriptor pFd (if the file -** is already mapped, the existing mapping is replaced by the new). Or, if -** there already exists a mapping for this file, and there are still -** outstanding xFetch() references to it, this function is a no-op. -** -** If parameter nByte is non-negative, then it is the requested size of -** the mapping to create. Otherwise, if nByte is less than zero, then the -** requested size is the size of the file on disk. The actual size of the -** created mapping is either the requested size or the value configured -** using SQLITE_FCNTL_MMAP_LIMIT, whichever is smaller. -** -** SQLITE_OK is returned if no error occurs (even if the mapping is not -** recreated as a result of outstanding references) or an SQLite error -** code otherwise. -*/ -static int unixMapfile(unixFile *pFd, i64 nByte){ - i64 nMap = nByte; - int rc; - - assert( nMap>=0 || pFd->nFetchOut==0 ); - if( pFd->nFetchOut>0 ) return SQLITE_OK; - - if( nMap<0 ){ - struct stat statbuf; /* Low-level file information */ - rc = osFstat(pFd->h, &statbuf); - if( rc!=SQLITE_OK ){ - return SQLITE_IOERR_FSTAT; - } - nMap = statbuf.st_size; - } - if( nMap>pFd->mmapSizeMax ){ - nMap = pFd->mmapSizeMax; - } - - if( nMap!=pFd->mmapSize ){ - if( nMap>0 ){ - unixRemapfile(pFd, nMap); - }else{ - unixUnmapfile(pFd); - } - } - - return SQLITE_OK; -} -#endif /* SQLITE_MAX_MMAP_SIZE>0 */ - -/* -** If possible, return a pointer to a mapping of file fd starting at offset -** iOff. The mapping must be valid for at least nAmt bytes. -** -** If such a pointer can be obtained, store it in *pp and return SQLITE_OK. -** Or, if one cannot but no error occurs, set *pp to 0 and return SQLITE_OK. -** Finally, if an error does occur, return an SQLite error code. The final -** value of *pp is undefined in this case. -** -** If this function does return a pointer, the caller must eventually -** release the reference by calling unixUnfetch(). -*/ -static int unixFetch(sqlite3_file *fd, i64 iOff, int nAmt, void **pp){ -#if SQLITE_MAX_MMAP_SIZE>0 - unixFile *pFd = (unixFile *)fd; /* The underlying database file */ -#endif - *pp = 0; - -#if SQLITE_MAX_MMAP_SIZE>0 - if( pFd->mmapSizeMax>0 ){ - if( pFd->pMapRegion==0 ){ - int rc = unixMapfile(pFd, -1); - if( rc!=SQLITE_OK ) return rc; - } - if( pFd->mmapSize >= iOff+nAmt ){ - *pp = &((u8 *)pFd->pMapRegion)[iOff]; - pFd->nFetchOut++; - } - } -#endif - return SQLITE_OK; -} - -/* -** If the third argument is non-NULL, then this function releases a -** reference obtained by an earlier call to unixFetch(). The second -** argument passed to this function must be the same as the corresponding -** argument that was passed to the unixFetch() invocation. -** -** Or, if the third argument is NULL, then this function is being called -** to inform the VFS layer that, according to POSIX, any existing mapping -** may now be invalid and should be unmapped. -*/ -static int unixUnfetch(sqlite3_file *fd, i64 iOff, void *p){ -#if SQLITE_MAX_MMAP_SIZE>0 - unixFile *pFd = (unixFile *)fd; /* The underlying database file */ - UNUSED_PARAMETER(iOff); - - /* If p==0 (unmap the entire file) then there must be no outstanding - ** xFetch references. Or, if p!=0 (meaning it is an xFetch reference), - ** then there must be at least one outstanding. */ - assert( (p==0)==(pFd->nFetchOut==0) ); - - /* If p!=0, it must match the iOff value. */ - assert( p==0 || p==&((u8 *)pFd->pMapRegion)[iOff] ); - - if( p ){ - pFd->nFetchOut--; - }else{ - unixUnmapfile(pFd); - } - - assert( pFd->nFetchOut>=0 ); -#else - UNUSED_PARAMETER(fd); - UNUSED_PARAMETER(p); - UNUSED_PARAMETER(iOff); -#endif - return SQLITE_OK; -} - -/* -** Here ends the implementation of all sqlite3_file methods. -** -********************** End sqlite3_file Methods ******************************* -******************************************************************************/ - -/* -** This division contains definitions of sqlite3_io_methods objects that -** implement various file locking strategies. It also contains definitions -** of "finder" functions. A finder-function is used to locate the appropriate -** sqlite3_io_methods object for a particular database file. The pAppData -** field of the sqlite3_vfs VFS objects are initialized to be pointers to -** the correct finder-function for that VFS. -** -** Most finder functions return a pointer to a fixed sqlite3_io_methods -** object. The only interesting finder-function is autolockIoFinder, which -** looks at the filesystem type and tries to guess the best locking -** strategy from that. -** -** For finder-function F, two objects are created: -** -** (1) The real finder-function named "FImpt()". -** -** (2) A constant pointer to this function named just "F". -** -** -** A pointer to the F pointer is used as the pAppData value for VFS -** objects. We have to do this instead of letting pAppData point -** directly at the finder-function since C90 rules prevent a void* -** from be cast into a function pointer. -** -** -** Each instance of this macro generates two objects: -** -** * A constant sqlite3_io_methods object call METHOD that has locking -** methods CLOSE, LOCK, UNLOCK, CKRESLOCK. -** -** * An I/O method finder function called FINDER that returns a pointer -** to the METHOD object in the previous bullet. -*/ -#define IOMETHODS(FINDER,METHOD,VERSION,CLOSE,LOCK,UNLOCK,CKLOCK,SHMMAP) \ -static const sqlite3_io_methods METHOD = { \ - VERSION, /* iVersion */ \ - CLOSE, /* xClose */ \ - unixRead, /* xRead */ \ - unixWrite, /* xWrite */ \ - unixTruncate, /* xTruncate */ \ - unixSync, /* xSync */ \ - unixFileSize, /* xFileSize */ \ - LOCK, /* xLock */ \ - UNLOCK, /* xUnlock */ \ - CKLOCK, /* xCheckReservedLock */ \ - unixFileControl, /* xFileControl */ \ - unixSectorSize, /* xSectorSize */ \ - unixDeviceCharacteristics, /* xDeviceCapabilities */ \ - SHMMAP, /* xShmMap */ \ - unixShmLock, /* xShmLock */ \ - unixShmBarrier, /* xShmBarrier */ \ - unixShmUnmap, /* xShmUnmap */ \ - unixFetch, /* xFetch */ \ - unixUnfetch, /* xUnfetch */ \ -}; \ -static const sqlite3_io_methods *FINDER##Impl(const char *z, unixFile *p){ \ - UNUSED_PARAMETER(z); UNUSED_PARAMETER(p); \ - return &METHOD; \ -} \ -static const sqlite3_io_methods *(*const FINDER)(const char*,unixFile *p) \ - = FINDER##Impl; - -/* -** Here are all of the sqlite3_io_methods objects for each of the -** locking strategies. Functions that return pointers to these methods -** are also created. -*/ -IOMETHODS( - posixIoFinder, /* Finder function name */ - posixIoMethods, /* sqlite3_io_methods object name */ - 3, /* shared memory and mmap are enabled */ - unixClose, /* xClose method */ - unixLock, /* xLock method */ - unixUnlock, /* xUnlock method */ - unixCheckReservedLock, /* xCheckReservedLock method */ - unixShmMap /* xShmMap method */ -) -IOMETHODS( - nolockIoFinder, /* Finder function name */ - nolockIoMethods, /* sqlite3_io_methods object name */ - 3, /* shared memory is disabled */ - nolockClose, /* xClose method */ - nolockLock, /* xLock method */ - nolockUnlock, /* xUnlock method */ - nolockCheckReservedLock, /* xCheckReservedLock method */ - 0 /* xShmMap method */ -) -IOMETHODS( - dotlockIoFinder, /* Finder function name */ - dotlockIoMethods, /* sqlite3_io_methods object name */ - 1, /* shared memory is disabled */ - dotlockClose, /* xClose method */ - dotlockLock, /* xLock method */ - dotlockUnlock, /* xUnlock method */ - dotlockCheckReservedLock, /* xCheckReservedLock method */ - 0 /* xShmMap method */ -) - -#if SQLITE_ENABLE_LOCKING_STYLE -IOMETHODS( - flockIoFinder, /* Finder function name */ - flockIoMethods, /* sqlite3_io_methods object name */ - 1, /* shared memory is disabled */ - flockClose, /* xClose method */ - flockLock, /* xLock method */ - flockUnlock, /* xUnlock method */ - flockCheckReservedLock, /* xCheckReservedLock method */ - 0 /* xShmMap method */ -) -#endif - -#if OS_VXWORKS -IOMETHODS( - semIoFinder, /* Finder function name */ - semIoMethods, /* sqlite3_io_methods object name */ - 1, /* shared memory is disabled */ - semXClose, /* xClose method */ - semXLock, /* xLock method */ - semXUnlock, /* xUnlock method */ - semXCheckReservedLock, /* xCheckReservedLock method */ - 0 /* xShmMap method */ -) -#endif - -#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE -IOMETHODS( - afpIoFinder, /* Finder function name */ - afpIoMethods, /* sqlite3_io_methods object name */ - 1, /* shared memory is disabled */ - afpClose, /* xClose method */ - afpLock, /* xLock method */ - afpUnlock, /* xUnlock method */ - afpCheckReservedLock, /* xCheckReservedLock method */ - 0 /* xShmMap method */ -) -#endif - -/* -** The proxy locking method is a "super-method" in the sense that it -** opens secondary file descriptors for the conch and lock files and -** it uses proxy, dot-file, AFP, and flock() locking methods on those -** secondary files. For this reason, the division that implements -** proxy locking is located much further down in the file. But we need -** to go ahead and define the sqlite3_io_methods and finder function -** for proxy locking here. So we forward declare the I/O methods. -*/ -#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE -static int proxyClose(sqlite3_file*); -static int proxyLock(sqlite3_file*, int); -static int proxyUnlock(sqlite3_file*, int); -static int proxyCheckReservedLock(sqlite3_file*, int*); -IOMETHODS( - proxyIoFinder, /* Finder function name */ - proxyIoMethods, /* sqlite3_io_methods object name */ - 1, /* shared memory is disabled */ - proxyClose, /* xClose method */ - proxyLock, /* xLock method */ - proxyUnlock, /* xUnlock method */ - proxyCheckReservedLock, /* xCheckReservedLock method */ - 0 /* xShmMap method */ -) -#endif - -/* nfs lockd on OSX 10.3+ doesn't clear write locks when a read lock is set */ -#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE -IOMETHODS( - nfsIoFinder, /* Finder function name */ - nfsIoMethods, /* sqlite3_io_methods object name */ - 1, /* shared memory is disabled */ - unixClose, /* xClose method */ - unixLock, /* xLock method */ - nfsUnlock, /* xUnlock method */ - unixCheckReservedLock, /* xCheckReservedLock method */ - 0 /* xShmMap method */ -) -#endif - -#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE -/* -** This "finder" function attempts to determine the best locking strategy -** for the database file "filePath". It then returns the sqlite3_io_methods -** object that implements that strategy. -** -** This is for MacOSX only. -*/ -static const sqlite3_io_methods *autolockIoFinderImpl( - const char *filePath, /* name of the database file */ - unixFile *pNew /* open file object for the database file */ -){ - static const struct Mapping { - const char *zFilesystem; /* Filesystem type name */ - const sqlite3_io_methods *pMethods; /* Appropriate locking method */ - } aMap[] = { - { "hfs", &posixIoMethods }, - { "ufs", &posixIoMethods }, - { "afpfs", &afpIoMethods }, - { "smbfs", &afpIoMethods }, - { "webdav", &nolockIoMethods }, - { 0, 0 } - }; - int i; - struct statfs fsInfo; - struct flock lockInfo; - - if( !filePath ){ - /* If filePath==NULL that means we are dealing with a transient file - ** that does not need to be locked. */ - return &nolockIoMethods; - } - if( statfs(filePath, &fsInfo) != -1 ){ - if( fsInfo.f_flags & MNT_RDONLY ){ - return &nolockIoMethods; - } - for(i=0; aMap[i].zFilesystem; i++){ - if( strcmp(fsInfo.f_fstypename, aMap[i].zFilesystem)==0 ){ - return aMap[i].pMethods; - } - } - } - - /* Default case. Handles, amongst others, "nfs". - ** Test byte-range lock using fcntl(). If the call succeeds, - ** assume that the file-system supports POSIX style locks. - */ - lockInfo.l_len = 1; - lockInfo.l_start = 0; - lockInfo.l_whence = SEEK_SET; - lockInfo.l_type = F_RDLCK; - if( osFcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) { - if( strcmp(fsInfo.f_fstypename, "nfs")==0 ){ - return &nfsIoMethods; - } else { - return &posixIoMethods; - } - }else{ - return &dotlockIoMethods; - } -} -static const sqlite3_io_methods - *(*const autolockIoFinder)(const char*,unixFile*) = autolockIoFinderImpl; - -#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */ - -#if OS_VXWORKS -/* -** This "finder" function for VxWorks checks to see if posix advisory -** locking works. If it does, then that is what is used. If it does not -** work, then fallback to named semaphore locking. -*/ -static const sqlite3_io_methods *vxworksIoFinderImpl( - const char *filePath, /* name of the database file */ - unixFile *pNew /* the open file object */ -){ - struct flock lockInfo; - - if( !filePath ){ - /* If filePath==NULL that means we are dealing with a transient file - ** that does not need to be locked. */ - return &nolockIoMethods; - } - - /* Test if fcntl() is supported and use POSIX style locks. - ** Otherwise fall back to the named semaphore method. - */ - lockInfo.l_len = 1; - lockInfo.l_start = 0; - lockInfo.l_whence = SEEK_SET; - lockInfo.l_type = F_RDLCK; - if( osFcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) { - return &posixIoMethods; - }else{ - return &semIoMethods; - } -} -static const sqlite3_io_methods - *(*const vxworksIoFinder)(const char*,unixFile*) = vxworksIoFinderImpl; - -#endif /* OS_VXWORKS */ - -/* -** An abstract type for a pointer to an IO method finder function: -*/ -typedef const sqlite3_io_methods *(*finder_type)(const char*,unixFile*); - - -/**************************************************************************** -**************************** sqlite3_vfs methods **************************** -** -** This division contains the implementation of methods on the -** sqlite3_vfs object. -*/ - -/* -** Initialize the contents of the unixFile structure pointed to by pId. -*/ -static int fillInUnixFile( - sqlite3_vfs *pVfs, /* Pointer to vfs object */ - int h, /* Open file descriptor of file being opened */ - sqlite3_file *pId, /* Write to the unixFile structure here */ - const char *zFilename, /* Name of the file being opened */ - int ctrlFlags /* Zero or more UNIXFILE_* values */ -){ - const sqlite3_io_methods *pLockingStyle; - unixFile *pNew = (unixFile *)pId; - int rc = SQLITE_OK; - - assert( pNew->pInode==NULL ); - - /* Usually the path zFilename should not be a relative pathname. The - ** exception is when opening the proxy "conch" file in builds that - ** include the special Apple locking styles. - */ -#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE - assert( zFilename==0 || zFilename[0]=='/' - || pVfs->pAppData==(void*)&autolockIoFinder ); -#else - assert( zFilename==0 || zFilename[0]=='/' ); -#endif - - /* No locking occurs in temporary files */ - assert( zFilename!=0 || (ctrlFlags & UNIXFILE_NOLOCK)!=0 ); - - OSTRACE(("OPEN %-3d %s\n", h, zFilename)); - pNew->h = h; - pNew->pVfs = pVfs; - pNew->zPath = zFilename; - pNew->ctrlFlags = (u8)ctrlFlags; -#if SQLITE_MAX_MMAP_SIZE>0 - pNew->mmapSizeMax = sqlite3GlobalConfig.szMmap; -#endif - if( sqlite3_uri_boolean(((ctrlFlags & UNIXFILE_URI) ? zFilename : 0), - "psow", SQLITE_POWERSAFE_OVERWRITE) ){ - pNew->ctrlFlags |= UNIXFILE_PSOW; - } - if( strcmp(pVfs->zName,"unix-excl")==0 ){ - pNew->ctrlFlags |= UNIXFILE_EXCL; - } - -#if OS_VXWORKS - pNew->pId = vxworksFindFileId(zFilename); - if( pNew->pId==0 ){ - ctrlFlags |= UNIXFILE_NOLOCK; - rc = SQLITE_NOMEM; - } -#endif - - if( ctrlFlags & UNIXFILE_NOLOCK ){ - pLockingStyle = &nolockIoMethods; - }else{ - pLockingStyle = (**(finder_type*)pVfs->pAppData)(zFilename, pNew); -#if SQLITE_ENABLE_LOCKING_STYLE - /* Cache zFilename in the locking context (AFP and dotlock override) for - ** proxyLock activation is possible (remote proxy is based on db name) - ** zFilename remains valid until file is closed, to support */ - pNew->lockingContext = (void*)zFilename; -#endif - } - - if( pLockingStyle == &posixIoMethods -#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE - || pLockingStyle == &nfsIoMethods -#endif - ){ - unixEnterMutex(); - rc = findInodeInfo(pNew, &pNew->pInode); - if( rc!=SQLITE_OK ){ - /* If an error occurred in findInodeInfo(), close the file descriptor - ** immediately, before releasing the mutex. findInodeInfo() may fail - ** in two scenarios: - ** - ** (a) A call to fstat() failed. - ** (b) A malloc failed. - ** - ** Scenario (b) may only occur if the process is holding no other - ** file descriptors open on the same file. If there were other file - ** descriptors on this file, then no malloc would be required by - ** findInodeInfo(). If this is the case, it is quite safe to close - ** handle h - as it is guaranteed that no posix locks will be released - ** by doing so. - ** - ** If scenario (a) caused the error then things are not so safe. The - ** implicit assumption here is that if fstat() fails, things are in - ** such bad shape that dropping a lock or two doesn't matter much. - */ - robust_close(pNew, h, __LINE__); - h = -1; - } - unixLeaveMutex(); - } - -#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) - else if( pLockingStyle == &afpIoMethods ){ - /* AFP locking uses the file path so it needs to be included in - ** the afpLockingContext. - */ - afpLockingContext *pCtx; - pNew->lockingContext = pCtx = sqlite3_malloc64( sizeof(*pCtx) ); - if( pCtx==0 ){ - rc = SQLITE_NOMEM; - }else{ - /* NB: zFilename exists and remains valid until the file is closed - ** according to requirement F11141. So we do not need to make a - ** copy of the filename. */ - pCtx->dbPath = zFilename; - pCtx->reserved = 0; - srandomdev(); - unixEnterMutex(); - rc = findInodeInfo(pNew, &pNew->pInode); - if( rc!=SQLITE_OK ){ - sqlite3_free(pNew->lockingContext); - robust_close(pNew, h, __LINE__); - h = -1; - } - unixLeaveMutex(); - } - } -#endif - - else if( pLockingStyle == &dotlockIoMethods ){ - /* Dotfile locking uses the file path so it needs to be included in - ** the dotlockLockingContext - */ - char *zLockFile; - int nFilename; - assert( zFilename!=0 ); - nFilename = (int)strlen(zFilename) + 6; - zLockFile = (char *)sqlite3_malloc64(nFilename); - if( zLockFile==0 ){ - rc = SQLITE_NOMEM; - }else{ - sqlite3_snprintf(nFilename, zLockFile, "%s" DOTLOCK_SUFFIX, zFilename); - } - pNew->lockingContext = zLockFile; - } - -#if OS_VXWORKS - else if( pLockingStyle == &semIoMethods ){ - /* Named semaphore locking uses the file path so it needs to be - ** included in the semLockingContext - */ - unixEnterMutex(); - rc = findInodeInfo(pNew, &pNew->pInode); - if( (rc==SQLITE_OK) && (pNew->pInode->pSem==NULL) ){ - char *zSemName = pNew->pInode->aSemName; - int n; - sqlite3_snprintf(MAX_PATHNAME, zSemName, "/%s.sem", - pNew->pId->zCanonicalName); - for( n=1; zSemName[n]; n++ ) - if( zSemName[n]=='/' ) zSemName[n] = '_'; - pNew->pInode->pSem = sem_open(zSemName, O_CREAT, 0666, 1); - if( pNew->pInode->pSem == SEM_FAILED ){ - rc = SQLITE_NOMEM; - pNew->pInode->aSemName[0] = '\0'; - } - } - unixLeaveMutex(); - } -#endif - - storeLastErrno(pNew, 0); -#if OS_VXWORKS - if( rc!=SQLITE_OK ){ - if( h>=0 ) robust_close(pNew, h, __LINE__); - h = -1; - osUnlink(zFilename); - pNew->ctrlFlags |= UNIXFILE_DELETE; - } -#endif - if( rc!=SQLITE_OK ){ - if( h>=0 ) robust_close(pNew, h, __LINE__); - }else{ - pNew->pMethod = pLockingStyle; - OpenCounter(+1); - verifyDbFile(pNew); - } - return rc; -} - -/* -** Return the name of a directory in which to put temporary files. -** If no suitable temporary file directory can be found, return NULL. -*/ -static const char *unixTempFileDir(void){ - static const char *azDirs[] = { - 0, - 0, - 0, - "/var/tmp", - "/usr/tmp", - "/tmp", - 0 /* List terminator */ - }; - unsigned int i; - struct stat buf; - const char *zDir = 0; - - azDirs[0] = sqlite3_temp_directory; - if( !azDirs[1] ) azDirs[1] = getenv("SQLITE_TMPDIR"); - if( !azDirs[2] ) azDirs[2] = getenv("TMPDIR"); - for(i=0; i<sizeof(azDirs)/sizeof(azDirs[0]); zDir=azDirs[i++]){ - if( zDir==0 ) continue; - if( osStat(zDir, &buf) ) continue; - if( !S_ISDIR(buf.st_mode) ) continue; - if( osAccess(zDir, 07) ) continue; - break; - } - return zDir; -} - -/* -** Create a temporary file name in zBuf. zBuf must be allocated -** by the calling process and must be big enough to hold at least -** pVfs->mxPathname bytes. -*/ -static int unixGetTempname(int nBuf, char *zBuf){ - static const unsigned char zChars[] = - "abcdefghijklmnopqrstuvwxyz" - "ABCDEFGHIJKLMNOPQRSTUVWXYZ" - "0123456789"; - unsigned int i, j; - const char *zDir; - - /* It's odd to simulate an io-error here, but really this is just - ** using the io-error infrastructure to test that SQLite handles this - ** function failing. - */ - SimulateIOError( return SQLITE_IOERR ); - - zDir = unixTempFileDir(); - if( zDir==0 ) zDir = "."; - - /* Check that the output buffer is large enough for the temporary file - ** name. If it is not, return SQLITE_ERROR. - */ - if( (strlen(zDir) + strlen(SQLITE_TEMP_FILE_PREFIX) + 18) >= (size_t)nBuf ){ - return SQLITE_ERROR; - } - - do{ - sqlite3_snprintf(nBuf-18, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX, zDir); - j = (int)strlen(zBuf); - sqlite3_randomness(15, &zBuf[j]); - for(i=0; i<15; i++, j++){ - zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ]; - } - zBuf[j] = 0; - zBuf[j+1] = 0; - }while( osAccess(zBuf,0)==0 ); - return SQLITE_OK; -} - -#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) -/* -** Routine to transform a unixFile into a proxy-locking unixFile. -** Implementation in the proxy-lock division, but used by unixOpen() -** if SQLITE_PREFER_PROXY_LOCKING is defined. -*/ -static int proxyTransformUnixFile(unixFile*, const char*); -#endif - -/* -** Search for an unused file descriptor that was opened on the database -** file (not a journal or master-journal file) identified by pathname -** zPath with SQLITE_OPEN_XXX flags matching those passed as the second -** argument to this function. -** -** Such a file descriptor may exist if a database connection was closed -** but the associated file descriptor could not be closed because some -** other file descriptor open on the same file is holding a file-lock. -** Refer to comments in the unixClose() function and the lengthy comment -** describing "Posix Advisory Locking" at the start of this file for -** further details. Also, ticket #4018. -** -** If a suitable file descriptor is found, then it is returned. If no -** such file descriptor is located, -1 is returned. -*/ -static UnixUnusedFd *findReusableFd(const char *zPath, int flags){ - UnixUnusedFd *pUnused = 0; - - /* Do not search for an unused file descriptor on vxworks. Not because - ** vxworks would not benefit from the change (it might, we're not sure), - ** but because no way to test it is currently available. It is better - ** not to risk breaking vxworks support for the sake of such an obscure - ** feature. */ -#if !OS_VXWORKS - struct stat sStat; /* Results of stat() call */ - - /* A stat() call may fail for various reasons. If this happens, it is - ** almost certain that an open() call on the same path will also fail. - ** For this reason, if an error occurs in the stat() call here, it is - ** ignored and -1 is returned. The caller will try to open a new file - ** descriptor on the same path, fail, and return an error to SQLite. - ** - ** Even if a subsequent open() call does succeed, the consequences of - ** not searching for a reusable file descriptor are not dire. */ - if( 0==osStat(zPath, &sStat) ){ - unixInodeInfo *pInode; - - unixEnterMutex(); - pInode = inodeList; - while( pInode && (pInode->fileId.dev!=sStat.st_dev - || pInode->fileId.ino!=sStat.st_ino) ){ - pInode = pInode->pNext; - } - if( pInode ){ - UnixUnusedFd **pp; - for(pp=&pInode->pUnused; *pp && (*pp)->flags!=flags; pp=&((*pp)->pNext)); - pUnused = *pp; - if( pUnused ){ - *pp = pUnused->pNext; - } - } - unixLeaveMutex(); - } -#endif /* if !OS_VXWORKS */ - return pUnused; -} - -/* -** This function is called by unixOpen() to determine the unix permissions -** to create new files with. If no error occurs, then SQLITE_OK is returned -** and a value suitable for passing as the third argument to open(2) is -** written to *pMode. If an IO error occurs, an SQLite error code is -** returned and the value of *pMode is not modified. -** -** In most cases, this routine sets *pMode to 0, which will become -** an indication to robust_open() to create the file using -** SQLITE_DEFAULT_FILE_PERMISSIONS adjusted by the umask. -** But if the file being opened is a WAL or regular journal file, then -** this function queries the file-system for the permissions on the -** corresponding database file and sets *pMode to this value. Whenever -** possible, WAL and journal files are created using the same permissions -** as the associated database file. -** -** If the SQLITE_ENABLE_8_3_NAMES option is enabled, then the -** original filename is unavailable. But 8_3_NAMES is only used for -** FAT filesystems and permissions do not matter there, so just use -** the default permissions. -*/ -static int findCreateFileMode( - const char *zPath, /* Path of file (possibly) being created */ - int flags, /* Flags passed as 4th argument to xOpen() */ - mode_t *pMode, /* OUT: Permissions to open file with */ - uid_t *pUid, /* OUT: uid to set on the file */ - gid_t *pGid /* OUT: gid to set on the file */ -){ - int rc = SQLITE_OK; /* Return Code */ - *pMode = 0; - *pUid = 0; - *pGid = 0; - if( flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL) ){ - char zDb[MAX_PATHNAME+1]; /* Database file path */ - int nDb; /* Number of valid bytes in zDb */ - struct stat sStat; /* Output of stat() on database file */ - - /* zPath is a path to a WAL or journal file. The following block derives - ** the path to the associated database file from zPath. This block handles - ** the following naming conventions: - ** - ** "<path to db>-journal" - ** "<path to db>-wal" - ** "<path to db>-journalNN" - ** "<path to db>-walNN" - ** - ** where NN is a decimal number. The NN naming schemes are - ** used by the test_multiplex.c module. - */ - nDb = sqlite3Strlen30(zPath) - 1; -#ifdef SQLITE_ENABLE_8_3_NAMES - while( nDb>0 && sqlite3Isalnum(zPath[nDb]) ) nDb--; - if( nDb==0 || zPath[nDb]!='-' ) return SQLITE_OK; -#else - while( zPath[nDb]!='-' ){ - assert( nDb>0 ); - assert( zPath[nDb]!='\n' ); - nDb--; - } -#endif - memcpy(zDb, zPath, nDb); - zDb[nDb] = '\0'; - - if( 0==osStat(zDb, &sStat) ){ - *pMode = sStat.st_mode & 0777; - *pUid = sStat.st_uid; - *pGid = sStat.st_gid; - }else{ - rc = SQLITE_IOERR_FSTAT; - } - }else if( flags & SQLITE_OPEN_DELETEONCLOSE ){ - *pMode = 0600; - } - return rc; -} - -/* -** Open the file zPath. -** -** Previously, the SQLite OS layer used three functions in place of this -** one: -** -** sqlite3OsOpenReadWrite(); -** sqlite3OsOpenReadOnly(); -** sqlite3OsOpenExclusive(); -** -** These calls correspond to the following combinations of flags: -** -** ReadWrite() -> (READWRITE | CREATE) -** ReadOnly() -> (READONLY) -** OpenExclusive() -> (READWRITE | CREATE | EXCLUSIVE) -** -** The old OpenExclusive() accepted a boolean argument - "delFlag". If -** true, the file was configured to be automatically deleted when the -** file handle closed. To achieve the same effect using this new -** interface, add the DELETEONCLOSE flag to those specified above for -** OpenExclusive(). -*/ -static int unixOpen( - sqlite3_vfs *pVfs, /* The VFS for which this is the xOpen method */ - const char *zPath, /* Pathname of file to be opened */ - sqlite3_file *pFile, /* The file descriptor to be filled in */ - int flags, /* Input flags to control the opening */ - int *pOutFlags /* Output flags returned to SQLite core */ -){ - unixFile *p = (unixFile *)pFile; - int fd = -1; /* File descriptor returned by open() */ - int openFlags = 0; /* Flags to pass to open() */ - int eType = flags&0xFFFFFF00; /* Type of file to open */ - int noLock; /* True to omit locking primitives */ - int rc = SQLITE_OK; /* Function Return Code */ - int ctrlFlags = 0; /* UNIXFILE_* flags */ - - int isExclusive = (flags & SQLITE_OPEN_EXCLUSIVE); - int isDelete = (flags & SQLITE_OPEN_DELETEONCLOSE); - int isCreate = (flags & SQLITE_OPEN_CREATE); - int isReadonly = (flags & SQLITE_OPEN_READONLY); - int isReadWrite = (flags & SQLITE_OPEN_READWRITE); -#if SQLITE_ENABLE_LOCKING_STYLE - int isAutoProxy = (flags & SQLITE_OPEN_AUTOPROXY); -#endif -#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE - struct statfs fsInfo; -#endif - - /* If creating a master or main-file journal, this function will open - ** a file-descriptor on the directory too. The first time unixSync() - ** is called the directory file descriptor will be fsync()ed and close()d. - */ - int syncDir = (isCreate && ( - eType==SQLITE_OPEN_MASTER_JOURNAL - || eType==SQLITE_OPEN_MAIN_JOURNAL - || eType==SQLITE_OPEN_WAL - )); - - /* If argument zPath is a NULL pointer, this function is required to open - ** a temporary file. Use this buffer to store the file name in. - */ - char zTmpname[MAX_PATHNAME+2]; - const char *zName = zPath; - - /* Check the following statements are true: - ** - ** (a) Exactly one of the READWRITE and READONLY flags must be set, and - ** (b) if CREATE is set, then READWRITE must also be set, and - ** (c) if EXCLUSIVE is set, then CREATE must also be set. - ** (d) if DELETEONCLOSE is set, then CREATE must also be set. - */ - assert((isReadonly==0 || isReadWrite==0) && (isReadWrite || isReadonly)); - assert(isCreate==0 || isReadWrite); - assert(isExclusive==0 || isCreate); - assert(isDelete==0 || isCreate); - - /* The main DB, main journal, WAL file and master journal are never - ** automatically deleted. Nor are they ever temporary files. */ - assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_DB ); - assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_JOURNAL ); - assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MASTER_JOURNAL ); - assert( (!isDelete && zName) || eType!=SQLITE_OPEN_WAL ); - - /* Assert that the upper layer has set one of the "file-type" flags. */ - assert( eType==SQLITE_OPEN_MAIN_DB || eType==SQLITE_OPEN_TEMP_DB - || eType==SQLITE_OPEN_MAIN_JOURNAL || eType==SQLITE_OPEN_TEMP_JOURNAL - || eType==SQLITE_OPEN_SUBJOURNAL || eType==SQLITE_OPEN_MASTER_JOURNAL - || eType==SQLITE_OPEN_TRANSIENT_DB || eType==SQLITE_OPEN_WAL - ); - - /* Detect a pid change and reset the PRNG. There is a race condition - ** here such that two or more threads all trying to open databases at - ** the same instant might all reset the PRNG. But multiple resets - ** are harmless. - */ - if( randomnessPid!=osGetpid(0) ){ - randomnessPid = osGetpid(0); - sqlite3_randomness(0,0); - } - - memset(p, 0, sizeof(unixFile)); - - if( eType==SQLITE_OPEN_MAIN_DB ){ - UnixUnusedFd *pUnused; - pUnused = findReusableFd(zName, flags); - if( pUnused ){ - fd = pUnused->fd; - }else{ - pUnused = sqlite3_malloc64(sizeof(*pUnused)); - if( !pUnused ){ - return SQLITE_NOMEM; - } - } - p->pUnused = pUnused; - - /* Database filenames are double-zero terminated if they are not - ** URIs with parameters. Hence, they can always be passed into - ** sqlite3_uri_parameter(). */ - assert( (flags & SQLITE_OPEN_URI) || zName[strlen(zName)+1]==0 ); - - }else if( !zName ){ - /* If zName is NULL, the upper layer is requesting a temp file. */ - assert(isDelete && !syncDir); - rc = unixGetTempname(MAX_PATHNAME+2, zTmpname); - if( rc!=SQLITE_OK ){ - return rc; - } - zName = zTmpname; - - /* Generated temporary filenames are always double-zero terminated - ** for use by sqlite3_uri_parameter(). */ - assert( zName[strlen(zName)+1]==0 ); - } - - /* Determine the value of the flags parameter passed to POSIX function - ** open(). These must be calculated even if open() is not called, as - ** they may be stored as part of the file handle and used by the - ** 'conch file' locking functions later on. */ - if( isReadonly ) openFlags |= O_RDONLY; - if( isReadWrite ) openFlags |= O_RDWR; - if( isCreate ) openFlags |= O_CREAT; - if( isExclusive ) openFlags |= (O_EXCL|O_NOFOLLOW); - openFlags |= (O_LARGEFILE|O_BINARY); - - if( fd<0 ){ - mode_t openMode; /* Permissions to create file with */ - uid_t uid; /* Userid for the file */ - gid_t gid; /* Groupid for the file */ - rc = findCreateFileMode(zName, flags, &openMode, &uid, &gid); - if( rc!=SQLITE_OK ){ - assert( !p->pUnused ); - assert( eType==SQLITE_OPEN_WAL || eType==SQLITE_OPEN_MAIN_JOURNAL ); - return rc; - } - fd = robust_open(zName, openFlags, openMode); - OSTRACE(("OPENX %-3d %s 0%o\n", fd, zName, openFlags)); - if( fd<0 && errno!=EISDIR && isReadWrite && !isExclusive ){ - /* Failed to open the file for read/write access. Try read-only. */ - flags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE); - openFlags &= ~(O_RDWR|O_CREAT); - flags |= SQLITE_OPEN_READONLY; - openFlags |= O_RDONLY; - isReadonly = 1; - fd = robust_open(zName, openFlags, openMode); - } - if( fd<0 ){ - rc = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zName); - goto open_finished; - } - - /* If this process is running as root and if creating a new rollback - ** journal or WAL file, set the ownership of the journal or WAL to be - ** the same as the original database. - */ - if( flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL) ){ - osFchown(fd, uid, gid); - } - } - assert( fd>=0 ); - if( pOutFlags ){ - *pOutFlags = flags; - } - - if( p->pUnused ){ - p->pUnused->fd = fd; - p->pUnused->flags = flags; - } - - if( isDelete ){ -#if OS_VXWORKS - zPath = zName; -#elif defined(SQLITE_UNLINK_AFTER_CLOSE) - zPath = sqlite3_mprintf("%s", zName); - if( zPath==0 ){ - robust_close(p, fd, __LINE__); - return SQLITE_NOMEM; - } -#else - osUnlink(zName); -#endif - } -#if SQLITE_ENABLE_LOCKING_STYLE - else{ - p->openFlags = openFlags; - } -#endif - - noLock = eType!=SQLITE_OPEN_MAIN_DB; - - -#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE - if( fstatfs(fd, &fsInfo) == -1 ){ - storeLastErrno(p, errno); - robust_close(p, fd, __LINE__); - return SQLITE_IOERR_ACCESS; - } - if (0 == strncmp("msdos", fsInfo.f_fstypename, 5)) { - ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS; - } - if (0 == strncmp("exfat", fsInfo.f_fstypename, 5)) { - ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS; - } -#endif - - /* Set up appropriate ctrlFlags */ - if( isDelete ) ctrlFlags |= UNIXFILE_DELETE; - if( isReadonly ) ctrlFlags |= UNIXFILE_RDONLY; - if( noLock ) ctrlFlags |= UNIXFILE_NOLOCK; - if( syncDir ) ctrlFlags |= UNIXFILE_DIRSYNC; - if( flags & SQLITE_OPEN_URI ) ctrlFlags |= UNIXFILE_URI; - -#if SQLITE_ENABLE_LOCKING_STYLE -#if SQLITE_PREFER_PROXY_LOCKING - isAutoProxy = 1; -#endif - if( isAutoProxy && (zPath!=NULL) && (!noLock) && pVfs->xOpen ){ - char *envforce = getenv("SQLITE_FORCE_PROXY_LOCKING"); - int useProxy = 0; - - /* SQLITE_FORCE_PROXY_LOCKING==1 means force always use proxy, 0 means - ** never use proxy, NULL means use proxy for non-local files only. */ - if( envforce!=NULL ){ - useProxy = atoi(envforce)>0; - }else{ - useProxy = !(fsInfo.f_flags&MNT_LOCAL); - } - if( useProxy ){ - rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags); - if( rc==SQLITE_OK ){ - rc = proxyTransformUnixFile((unixFile*)pFile, ":auto:"); - if( rc!=SQLITE_OK ){ - /* Use unixClose to clean up the resources added in fillInUnixFile - ** and clear all the structure's references. Specifically, - ** pFile->pMethods will be NULL so sqlite3OsClose will be a no-op - */ - unixClose(pFile); - return rc; - } - } - goto open_finished; - } - } -#endif - - rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags); - -open_finished: - if( rc!=SQLITE_OK ){ - sqlite3_free(p->pUnused); - } - return rc; -} - - -/* -** Delete the file at zPath. If the dirSync argument is true, fsync() -** the directory after deleting the file. -*/ -static int unixDelete( - sqlite3_vfs *NotUsed, /* VFS containing this as the xDelete method */ - const char *zPath, /* Name of file to be deleted */ - int dirSync /* If true, fsync() directory after deleting file */ -){ - int rc = SQLITE_OK; - UNUSED_PARAMETER(NotUsed); - SimulateIOError(return SQLITE_IOERR_DELETE); - if( osUnlink(zPath)==(-1) ){ - if( errno==ENOENT -#if OS_VXWORKS - || osAccess(zPath,0)!=0 -#endif - ){ - rc = SQLITE_IOERR_DELETE_NOENT; - }else{ - rc = unixLogError(SQLITE_IOERR_DELETE, "unlink", zPath); - } - return rc; - } -#ifndef SQLITE_DISABLE_DIRSYNC - if( (dirSync & 1)!=0 ){ - int fd; - rc = osOpenDirectory(zPath, &fd); - if( rc==SQLITE_OK ){ -#if OS_VXWORKS - if( fsync(fd)==-1 ) -#else - if( fsync(fd) ) -#endif - { - rc = unixLogError(SQLITE_IOERR_DIR_FSYNC, "fsync", zPath); - } - robust_close(0, fd, __LINE__); - }else if( rc==SQLITE_CANTOPEN ){ - rc = SQLITE_OK; - } - } -#endif - return rc; -} - -/* -** Test the existence of or access permissions of file zPath. The -** test performed depends on the value of flags: -** -** SQLITE_ACCESS_EXISTS: Return 1 if the file exists -** SQLITE_ACCESS_READWRITE: Return 1 if the file is read and writable. -** SQLITE_ACCESS_READONLY: Return 1 if the file is readable. -** -** Otherwise return 0. -*/ -static int unixAccess( - sqlite3_vfs *NotUsed, /* The VFS containing this xAccess method */ - const char *zPath, /* Path of the file to examine */ - int flags, /* What do we want to learn about the zPath file? */ - int *pResOut /* Write result boolean here */ -){ - int amode = 0; - UNUSED_PARAMETER(NotUsed); - SimulateIOError( return SQLITE_IOERR_ACCESS; ); - switch( flags ){ - case SQLITE_ACCESS_EXISTS: - amode = F_OK; - break; - case SQLITE_ACCESS_READWRITE: - amode = W_OK|R_OK; - break; - case SQLITE_ACCESS_READ: - amode = R_OK; - break; - - default: - assert(!"Invalid flags argument"); - } - *pResOut = (osAccess(zPath, amode)==0); - if( flags==SQLITE_ACCESS_EXISTS && *pResOut ){ - struct stat buf; - if( 0==osStat(zPath, &buf) && buf.st_size==0 ){ - *pResOut = 0; - } - } - return SQLITE_OK; -} - - -/* -** Turn a relative pathname into a full pathname. The relative path -** is stored as a nul-terminated string in the buffer pointed to by -** zPath. -** -** zOut points to a buffer of at least sqlite3_vfs.mxPathname bytes -** (in this case, MAX_PATHNAME bytes). The full-path is written to -** this buffer before returning. -*/ -static int unixFullPathname( - sqlite3_vfs *pVfs, /* Pointer to vfs object */ - const char *zPath, /* Possibly relative input path */ - int nOut, /* Size of output buffer in bytes */ - char *zOut /* Output buffer */ -){ - - /* It's odd to simulate an io-error here, but really this is just - ** using the io-error infrastructure to test that SQLite handles this - ** function failing. This function could fail if, for example, the - ** current working directory has been unlinked. - */ - SimulateIOError( return SQLITE_ERROR ); - - assert( pVfs->mxPathname==MAX_PATHNAME ); - UNUSED_PARAMETER(pVfs); - - zOut[nOut-1] = '\0'; - if( zPath[0]=='/' ){ - sqlite3_snprintf(nOut, zOut, "%s", zPath); - }else{ - int nCwd; - if( osGetcwd(zOut, nOut-1)==0 ){ - return unixLogError(SQLITE_CANTOPEN_BKPT, "getcwd", zPath); - } - nCwd = (int)strlen(zOut); - sqlite3_snprintf(nOut-nCwd, &zOut[nCwd], "/%s", zPath); - } - return SQLITE_OK; -} - - -#ifndef SQLITE_OMIT_LOAD_EXTENSION -/* -** Interfaces for opening a shared library, finding entry points -** within the shared library, and closing the shared library. -*/ -#include <dlfcn.h> -static void *unixDlOpen(sqlite3_vfs *NotUsed, const char *zFilename){ - UNUSED_PARAMETER(NotUsed); - return dlopen(zFilename, RTLD_NOW | RTLD_GLOBAL); -} - -/* -** SQLite calls this function immediately after a call to unixDlSym() or -** unixDlOpen() fails (returns a null pointer). If a more detailed error -** message is available, it is written to zBufOut. If no error message -** is available, zBufOut is left unmodified and SQLite uses a default -** error message. -*/ -static void unixDlError(sqlite3_vfs *NotUsed, int nBuf, char *zBufOut){ - const char *zErr; - UNUSED_PARAMETER(NotUsed); - unixEnterMutex(); - zErr = dlerror(); - if( zErr ){ - sqlite3_snprintf(nBuf, zBufOut, "%s", zErr); - } - unixLeaveMutex(); -} -static void (*unixDlSym(sqlite3_vfs *NotUsed, void *p, const char*zSym))(void){ - /* - ** GCC with -pedantic-errors says that C90 does not allow a void* to be - ** cast into a pointer to a function. And yet the library dlsym() routine - ** returns a void* which is really a pointer to a function. So how do we - ** use dlsym() with -pedantic-errors? - ** - ** Variable x below is defined to be a pointer to a function taking - ** parameters void* and const char* and returning a pointer to a function. - ** We initialize x by assigning it a pointer to the dlsym() function. - ** (That assignment requires a cast.) Then we call the function that - ** x points to. - ** - ** This work-around is unlikely to work correctly on any system where - ** you really cannot cast a function pointer into void*. But then, on the - ** other hand, dlsym() will not work on such a system either, so we have - ** not really lost anything. - */ - void (*(*x)(void*,const char*))(void); - UNUSED_PARAMETER(NotUsed); - x = (void(*(*)(void*,const char*))(void))dlsym; - return (*x)(p, zSym); -} -static void unixDlClose(sqlite3_vfs *NotUsed, void *pHandle){ - UNUSED_PARAMETER(NotUsed); - dlclose(pHandle); -} -#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */ - #define unixDlOpen 0 - #define unixDlError 0 - #define unixDlSym 0 - #define unixDlClose 0 -#endif - -/* -** Write nBuf bytes of random data to the supplied buffer zBuf. -*/ -static int unixRandomness(sqlite3_vfs *NotUsed, int nBuf, char *zBuf){ - UNUSED_PARAMETER(NotUsed); - assert((size_t)nBuf>=(sizeof(time_t)+sizeof(int))); - - /* We have to initialize zBuf to prevent valgrind from reporting - ** errors. The reports issued by valgrind are incorrect - we would - ** prefer that the randomness be increased by making use of the - ** uninitialized space in zBuf - but valgrind errors tend to worry - ** some users. Rather than argue, it seems easier just to initialize - ** the whole array and silence valgrind, even if that means less randomness - ** in the random seed. - ** - ** When testing, initializing zBuf[] to zero is all we do. That means - ** that we always use the same random number sequence. This makes the - ** tests repeatable. - */ - memset(zBuf, 0, nBuf); - randomnessPid = osGetpid(0); -#if !defined(SQLITE_TEST) && !defined(SQLITE_OMIT_RANDOMNESS) -# if HAVE_ARC4RANDOM_BUF - arc4random_buf(zBuf, nBuf); -# else - { - int fd, got; - fd = robust_open("/dev/urandom", O_RDONLY, 0); - if( fd<0 ){ - time_t t; - time(&t); - memcpy(zBuf, &t, sizeof(t)); - memcpy(&zBuf[sizeof(t)], &randomnessPid, sizeof(randomnessPid)); - assert( sizeof(t)+sizeof(randomnessPid)<=(size_t)nBuf ); - nBuf = sizeof(t) + sizeof(randomnessPid); - }else{ - do{ got = osRead(fd, zBuf, nBuf); }while( got<0 && errno==EINTR ); - robust_close(0, fd, __LINE__); - } - } -# endif -#endif - return nBuf; -} - - -/* -** Sleep for a little while. Return the amount of time slept. -** The argument is the number of microseconds we want to sleep. -** The return value is the number of microseconds of sleep actually -** requested from the underlying operating system, a number which -** might be greater than or equal to the argument, but not less -** than the argument. -*/ -static int unixSleep(sqlite3_vfs *NotUsed, int microseconds){ -#if OS_VXWORKS - struct timespec sp; - - sp.tv_sec = microseconds / 1000000; - sp.tv_nsec = (microseconds % 1000000) * 1000; - nanosleep(&sp, NULL); - UNUSED_PARAMETER(NotUsed); - return microseconds; -#elif defined(HAVE_USLEEP) && HAVE_USLEEP - usleep(microseconds); - UNUSED_PARAMETER(NotUsed); - return microseconds; -#else - int seconds = (microseconds+999999)/1000000; - sleep(seconds); - UNUSED_PARAMETER(NotUsed); - return seconds*1000000; -#endif -} - -/* -** The following variable, if set to a non-zero value, is interpreted as -** the number of seconds since 1970 and is used to set the result of -** sqlite3OsCurrentTime() during testing. -*/ -#ifdef SQLITE_TEST -int sqlite3_current_time = 0; /* Fake system time in seconds since 1970. */ -#endif - -/* -** Find the current time (in Universal Coordinated Time). Write into *piNow -** the current time and date as a Julian Day number times 86_400_000. In -** other words, write into *piNow the number of milliseconds since the Julian -** epoch of noon in Greenwich on November 24, 4714 B.C according to the -** proleptic Gregorian calendar. -** -** On success, return SQLITE_OK. Return SQLITE_ERROR if the time and date -** cannot be found. -*/ -static int unixCurrentTimeInt64(sqlite3_vfs *NotUsed, sqlite3_int64 *piNow){ - static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000; - int rc = SQLITE_OK; -#if defined(NO_GETTOD) - time_t t; - time(&t); - *piNow = ((sqlite3_int64)t)*1000 + unixEpoch; -#elif OS_VXWORKS - struct timespec sNow; - clock_gettime(CLOCK_REALTIME, &sNow); - *piNow = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_nsec/1000000; -#else - struct timeval sNow; - if( gettimeofday(&sNow, 0)==0 ){ - *piNow = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_usec/1000; - }else{ - rc = SQLITE_ERROR; - } -#endif - -#ifdef SQLITE_TEST - if( sqlite3_current_time ){ - *piNow = 1000*(sqlite3_int64)sqlite3_current_time + unixEpoch; - } -#endif - UNUSED_PARAMETER(NotUsed); - return rc; -} - -/* -** Find the current time (in Universal Coordinated Time). Write the -** current time and date as a Julian Day number into *prNow and -** return 0. Return 1 if the time and date cannot be found. -*/ -static int unixCurrentTime(sqlite3_vfs *NotUsed, double *prNow){ - sqlite3_int64 i = 0; - int rc; - UNUSED_PARAMETER(NotUsed); - rc = unixCurrentTimeInt64(0, &i); - *prNow = i/86400000.0; - return rc; -} - -/* -** We added the xGetLastError() method with the intention of providing -** better low-level error messages when operating-system problems come up -** during SQLite operation. But so far, none of that has been implemented -** in the core. So this routine is never called. For now, it is merely -** a place-holder. -*/ -static int unixGetLastError(sqlite3_vfs *NotUsed, int NotUsed2, char *NotUsed3){ - UNUSED_PARAMETER(NotUsed); - UNUSED_PARAMETER(NotUsed2); - UNUSED_PARAMETER(NotUsed3); - return 0; -} - - -/* -************************ End of sqlite3_vfs methods *************************** -******************************************************************************/ - -/****************************************************************************** -************************** Begin Proxy Locking ******************************** -** -** Proxy locking is a "uber-locking-method" in this sense: It uses the -** other locking methods on secondary lock files. Proxy locking is a -** meta-layer over top of the primitive locking implemented above. For -** this reason, the division that implements of proxy locking is deferred -** until late in the file (here) after all of the other I/O methods have -** been defined - so that the primitive locking methods are available -** as services to help with the implementation of proxy locking. -** -**** -** -** The default locking schemes in SQLite use byte-range locks on the -** database file to coordinate safe, concurrent access by multiple readers -** and writers [http://sqlite.org/lockingv3.html]. The five file locking -** states (UNLOCKED, PENDING, SHARED, RESERVED, EXCLUSIVE) are implemented -** as POSIX read & write locks over fixed set of locations (via fsctl), -** on AFP and SMB only exclusive byte-range locks are available via fsctl -** with _IOWR('z', 23, struct ByteRangeLockPB2) to track the same 5 states. -** To simulate a F_RDLCK on the shared range, on AFP a randomly selected -** address in the shared range is taken for a SHARED lock, the entire -** shared range is taken for an EXCLUSIVE lock): -** -** PENDING_BYTE 0x40000000 -** RESERVED_BYTE 0x40000001 -** SHARED_RANGE 0x40000002 -> 0x40000200 -** -** This works well on the local file system, but shows a nearly 100x -** slowdown in read performance on AFP because the AFP client disables -** the read cache when byte-range locks are present. Enabling the read -** cache exposes a cache coherency problem that is present on all OS X -** supported network file systems. NFS and AFP both observe the -** close-to-open semantics for ensuring cache coherency -** [http://nfs.sourceforge.net/#faq_a8], which does not effectively -** address the requirements for concurrent database access by multiple -** readers and writers -** [http://www.nabble.com/SQLite-on-NFS-cache-coherency-td15655701.html]. -** -** To address the performance and cache coherency issues, proxy file locking -** changes the way database access is controlled by limiting access to a -** single host at a time and moving file locks off of the database file -** and onto a proxy file on the local file system. -** -** -** Using proxy locks -** ----------------- -** -** C APIs -** -** sqlite3_file_control(db, dbname, SQLITE_FCNTL_SET_LOCKPROXYFILE, -** <proxy_path> | ":auto:"); -** sqlite3_file_control(db, dbname, SQLITE_FCNTL_GET_LOCKPROXYFILE, -** &<proxy_path>); -** -** -** SQL pragmas -** -** PRAGMA [database.]lock_proxy_file=<proxy_path> | :auto: -** PRAGMA [database.]lock_proxy_file -** -** Specifying ":auto:" means that if there is a conch file with a matching -** host ID in it, the proxy path in the conch file will be used, otherwise -** a proxy path based on the user's temp dir -** (via confstr(_CS_DARWIN_USER_TEMP_DIR,...)) will be used and the -** actual proxy file name is generated from the name and path of the -** database file. For example: -** -** For database path "/Users/me/foo.db" -** The lock path will be "<tmpdir>/sqliteplocks/_Users_me_foo.db:auto:") -** -** Once a lock proxy is configured for a database connection, it can not -** be removed, however it may be switched to a different proxy path via -** the above APIs (assuming the conch file is not being held by another -** connection or process). -** -** -** How proxy locking works -** ----------------------- -** -** Proxy file locking relies primarily on two new supporting files: -** -** * conch file to limit access to the database file to a single host -** at a time -** -** * proxy file to act as a proxy for the advisory locks normally -** taken on the database -** -** The conch file - to use a proxy file, sqlite must first "hold the conch" -** by taking an sqlite-style shared lock on the conch file, reading the -** contents and comparing the host's unique host ID (see below) and lock -** proxy path against the values stored in the conch. The conch file is -** stored in the same directory as the database file and the file name -** is patterned after the database file name as ".<databasename>-conch". -** If the conch file does not exist, or its contents do not match the -** host ID and/or proxy path, then the lock is escalated to an exclusive -** lock and the conch file contents is updated with the host ID and proxy -** path and the lock is downgraded to a shared lock again. If the conch -** is held by another process (with a shared lock), the exclusive lock -** will fail and SQLITE_BUSY is returned. -** -** The proxy file - a single-byte file used for all advisory file locks -** normally taken on the database file. This allows for safe sharing -** of the database file for multiple readers and writers on the same -** host (the conch ensures that they all use the same local lock file). -** -** Requesting the lock proxy does not immediately take the conch, it is -** only taken when the first request to lock database file is made. -** This matches the semantics of the traditional locking behavior, where -** opening a connection to a database file does not take a lock on it. -** The shared lock and an open file descriptor are maintained until -** the connection to the database is closed. -** -** The proxy file and the lock file are never deleted so they only need -** to be created the first time they are used. -** -** Configuration options -** --------------------- -** -** SQLITE_PREFER_PROXY_LOCKING -** -** Database files accessed on non-local file systems are -** automatically configured for proxy locking, lock files are -** named automatically using the same logic as -** PRAGMA lock_proxy_file=":auto:" -** -** SQLITE_PROXY_DEBUG -** -** Enables the logging of error messages during host id file -** retrieval and creation -** -** LOCKPROXYDIR -** -** Overrides the default directory used for lock proxy files that -** are named automatically via the ":auto:" setting -** -** SQLITE_DEFAULT_PROXYDIR_PERMISSIONS -** -** Permissions to use when creating a directory for storing the -** lock proxy files, only used when LOCKPROXYDIR is not set. -** -** -** As mentioned above, when compiled with SQLITE_PREFER_PROXY_LOCKING, -** setting the environment variable SQLITE_FORCE_PROXY_LOCKING to 1 will -** force proxy locking to be used for every database file opened, and 0 -** will force automatic proxy locking to be disabled for all database -** files (explicitly calling the SQLITE_FCNTL_SET_LOCKPROXYFILE pragma or -** sqlite_file_control API is not affected by SQLITE_FORCE_PROXY_LOCKING). -*/ - -/* -** Proxy locking is only available on MacOSX -*/ -#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE - -/* -** The proxyLockingContext has the path and file structures for the remote -** and local proxy files in it -*/ -typedef struct proxyLockingContext proxyLockingContext; -struct proxyLockingContext { - unixFile *conchFile; /* Open conch file */ - char *conchFilePath; /* Name of the conch file */ - unixFile *lockProxy; /* Open proxy lock file */ - char *lockProxyPath; /* Name of the proxy lock file */ - char *dbPath; /* Name of the open file */ - int conchHeld; /* 1 if the conch is held, -1 if lockless */ - int nFails; /* Number of conch taking failures */ - void *oldLockingContext; /* Original lockingcontext to restore on close */ - sqlite3_io_methods const *pOldMethod; /* Original I/O methods for close */ -}; - -/* -** The proxy lock file path for the database at dbPath is written into lPath, -** which must point to valid, writable memory large enough for a maxLen length -** file path. -*/ -static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){ - int len; - int dbLen; - int i; - -#ifdef LOCKPROXYDIR - len = strlcpy(lPath, LOCKPROXYDIR, maxLen); -#else -# ifdef _CS_DARWIN_USER_TEMP_DIR - { - if( !confstr(_CS_DARWIN_USER_TEMP_DIR, lPath, maxLen) ){ - OSTRACE(("GETLOCKPATH failed %s errno=%d pid=%d\n", - lPath, errno, osGetpid(0))); - return SQLITE_IOERR_LOCK; - } - len = strlcat(lPath, "sqliteplocks", maxLen); - } -# else - len = strlcpy(lPath, "/tmp/", maxLen); -# endif -#endif - - if( lPath[len-1]!='/' ){ - len = strlcat(lPath, "/", maxLen); - } - - /* transform the db path to a unique cache name */ - dbLen = (int)strlen(dbPath); - for( i=0; i<dbLen && (i+len+7)<(int)maxLen; i++){ - char c = dbPath[i]; - lPath[i+len] = (c=='/')?'_':c; - } - lPath[i+len]='\0'; - strlcat(lPath, ":auto:", maxLen); - OSTRACE(("GETLOCKPATH proxy lock path=%s pid=%d\n", lPath, osGetpid(0))); - return SQLITE_OK; -} - -/* - ** Creates the lock file and any missing directories in lockPath - */ -static int proxyCreateLockPath(const char *lockPath){ - int i, len; - char buf[MAXPATHLEN]; - int start = 0; - - assert(lockPath!=NULL); - /* try to create all the intermediate directories */ - len = (int)strlen(lockPath); - buf[0] = lockPath[0]; - for( i=1; i<len; i++ ){ - if( lockPath[i] == '/' && (i - start > 0) ){ - /* only mkdir if leaf dir != "." or "/" or ".." */ - if( i-start>2 || (i-start==1 && buf[start] != '.' && buf[start] != '/') - || (i-start==2 && buf[start] != '.' && buf[start+1] != '.') ){ - buf[i]='\0'; - if( osMkdir(buf, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){ - int err=errno; - if( err!=EEXIST ) { - OSTRACE(("CREATELOCKPATH FAILED creating %s, " - "'%s' proxy lock path=%s pid=%d\n", - buf, strerror(err), lockPath, osGetpid(0))); - return err; - } - } - } - start=i+1; - } - buf[i] = lockPath[i]; - } - OSTRACE(("CREATELOCKPATH proxy lock path=%s pid=%d\n", lockPath, osGetpid(0))); - return 0; -} - -/* -** Create a new VFS file descriptor (stored in memory obtained from -** sqlite3_malloc) and open the file named "path" in the file descriptor. -** -** The caller is responsible not only for closing the file descriptor -** but also for freeing the memory associated with the file descriptor. -*/ -static int proxyCreateUnixFile( - const char *path, /* path for the new unixFile */ - unixFile **ppFile, /* unixFile created and returned by ref */ - int islockfile /* if non zero missing dirs will be created */ -) { - int fd = -1; - unixFile *pNew; - int rc = SQLITE_OK; - int openFlags = O_RDWR | O_CREAT; - sqlite3_vfs dummyVfs; - int terrno = 0; - UnixUnusedFd *pUnused = NULL; - - /* 1. first try to open/create the file - ** 2. if that fails, and this is a lock file (not-conch), try creating - ** the parent directories and then try again. - ** 3. if that fails, try to open the file read-only - ** otherwise return BUSY (if lock file) or CANTOPEN for the conch file - */ - pUnused = findReusableFd(path, openFlags); - if( pUnused ){ - fd = pUnused->fd; - }else{ - pUnused = sqlite3_malloc64(sizeof(*pUnused)); - if( !pUnused ){ - return SQLITE_NOMEM; - } - } - if( fd<0 ){ - fd = robust_open(path, openFlags, 0); - terrno = errno; - if( fd<0 && errno==ENOENT && islockfile ){ - if( proxyCreateLockPath(path) == SQLITE_OK ){ - fd = robust_open(path, openFlags, 0); - } - } - } - if( fd<0 ){ - openFlags = O_RDONLY; - fd = robust_open(path, openFlags, 0); - terrno = errno; - } - if( fd<0 ){ - if( islockfile ){ - return SQLITE_BUSY; - } - switch (terrno) { - case EACCES: - return SQLITE_PERM; - case EIO: - return SQLITE_IOERR_LOCK; /* even though it is the conch */ - default: - return SQLITE_CANTOPEN_BKPT; - } - } - - pNew = (unixFile *)sqlite3_malloc64(sizeof(*pNew)); - if( pNew==NULL ){ - rc = SQLITE_NOMEM; - goto end_create_proxy; - } - memset(pNew, 0, sizeof(unixFile)); - pNew->openFlags = openFlags; - memset(&dummyVfs, 0, sizeof(dummyVfs)); - dummyVfs.pAppData = (void*)&autolockIoFinder; - dummyVfs.zName = "dummy"; - pUnused->fd = fd; - pUnused->flags = openFlags; - pNew->pUnused = pUnused; - - rc = fillInUnixFile(&dummyVfs, fd, (sqlite3_file*)pNew, path, 0); - if( rc==SQLITE_OK ){ - *ppFile = pNew; - return SQLITE_OK; - } -end_create_proxy: - robust_close(pNew, fd, __LINE__); - sqlite3_free(pNew); - sqlite3_free(pUnused); - return rc; -} - -#ifdef SQLITE_TEST -/* simulate multiple hosts by creating unique hostid file paths */ -int sqlite3_hostid_num = 0; -#endif - -#define PROXY_HOSTIDLEN 16 /* conch file host id length */ - -#ifdef HAVE_GETHOSTUUID -/* Not always defined in the headers as it ought to be */ -extern int gethostuuid(uuid_t id, const struct timespec *wait); -#endif - -/* get the host ID via gethostuuid(), pHostID must point to PROXY_HOSTIDLEN -** bytes of writable memory. -*/ -static int proxyGetHostID(unsigned char *pHostID, int *pError){ - assert(PROXY_HOSTIDLEN == sizeof(uuid_t)); - memset(pHostID, 0, PROXY_HOSTIDLEN); -#ifdef HAVE_GETHOSTUUID - { - struct timespec timeout = {1, 0}; /* 1 sec timeout */ - if( gethostuuid(pHostID, &timeout) ){ - int err = errno; - if( pError ){ - *pError = err; - } - return SQLITE_IOERR; - } - } -#else - UNUSED_PARAMETER(pError); -#endif -#ifdef SQLITE_TEST - /* simulate multiple hosts by creating unique hostid file paths */ - if( sqlite3_hostid_num != 0){ - pHostID[0] = (char)(pHostID[0] + (char)(sqlite3_hostid_num & 0xFF)); - } -#endif - - return SQLITE_OK; -} - -/* The conch file contains the header, host id and lock file path - */ -#define PROXY_CONCHVERSION 2 /* 1-byte header, 16-byte host id, path */ -#define PROXY_HEADERLEN 1 /* conch file header length */ -#define PROXY_PATHINDEX (PROXY_HEADERLEN+PROXY_HOSTIDLEN) -#define PROXY_MAXCONCHLEN (PROXY_HEADERLEN+PROXY_HOSTIDLEN+MAXPATHLEN) - -/* -** Takes an open conch file, copies the contents to a new path and then moves -** it back. The newly created file's file descriptor is assigned to the -** conch file structure and finally the original conch file descriptor is -** closed. Returns zero if successful. -*/ -static int proxyBreakConchLock(unixFile *pFile, uuid_t myHostID){ - proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; - unixFile *conchFile = pCtx->conchFile; - char tPath[MAXPATHLEN]; - char buf[PROXY_MAXCONCHLEN]; - char *cPath = pCtx->conchFilePath; - size_t readLen = 0; - size_t pathLen = 0; - char errmsg[64] = ""; - int fd = -1; - int rc = -1; - UNUSED_PARAMETER(myHostID); - - /* create a new path by replace the trailing '-conch' with '-break' */ - pathLen = strlcpy(tPath, cPath, MAXPATHLEN); - if( pathLen>MAXPATHLEN || pathLen<6 || - (strlcpy(&tPath[pathLen-5], "break", 6) != 5) ){ - sqlite3_snprintf(sizeof(errmsg),errmsg,"path error (len %d)",(int)pathLen); - goto end_breaklock; - } - /* read the conch content */ - readLen = osPread(conchFile->h, buf, PROXY_MAXCONCHLEN, 0); - if( readLen<PROXY_PATHINDEX ){ - sqlite3_snprintf(sizeof(errmsg),errmsg,"read error (len %d)",(int)readLen); - goto end_breaklock; - } - /* write it out to the temporary break file */ - fd = robust_open(tPath, (O_RDWR|O_CREAT|O_EXCL), 0); - if( fd<0 ){ - sqlite3_snprintf(sizeof(errmsg), errmsg, "create failed (%d)", errno); - goto end_breaklock; - } - if( osPwrite(fd, buf, readLen, 0) != (ssize_t)readLen ){ - sqlite3_snprintf(sizeof(errmsg), errmsg, "write failed (%d)", errno); - goto end_breaklock; - } - if( rename(tPath, cPath) ){ - sqlite3_snprintf(sizeof(errmsg), errmsg, "rename failed (%d)", errno); - goto end_breaklock; - } - rc = 0; - fprintf(stderr, "broke stale lock on %s\n", cPath); - robust_close(pFile, conchFile->h, __LINE__); - conchFile->h = fd; - conchFile->openFlags = O_RDWR | O_CREAT; - -end_breaklock: - if( rc ){ - if( fd>=0 ){ - osUnlink(tPath); - robust_close(pFile, fd, __LINE__); - } - fprintf(stderr, "failed to break stale lock on %s, %s\n", cPath, errmsg); - } - return rc; -} - -/* Take the requested lock on the conch file and break a stale lock if the -** host id matches. -*/ -static int proxyConchLock(unixFile *pFile, uuid_t myHostID, int lockType){ - proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; - unixFile *conchFile = pCtx->conchFile; - int rc = SQLITE_OK; - int nTries = 0; - struct timespec conchModTime; - - memset(&conchModTime, 0, sizeof(conchModTime)); - do { - rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType); - nTries ++; - if( rc==SQLITE_BUSY ){ - /* If the lock failed (busy): - * 1st try: get the mod time of the conch, wait 0.5s and try again. - * 2nd try: fail if the mod time changed or host id is different, wait - * 10 sec and try again - * 3rd try: break the lock unless the mod time has changed. - */ - struct stat buf; - if( osFstat(conchFile->h, &buf) ){ - storeLastErrno(pFile, errno); - return SQLITE_IOERR_LOCK; - } - - if( nTries==1 ){ - conchModTime = buf.st_mtimespec; - usleep(500000); /* wait 0.5 sec and try the lock again*/ - continue; - } - - assert( nTries>1 ); - if( conchModTime.tv_sec != buf.st_mtimespec.tv_sec || - conchModTime.tv_nsec != buf.st_mtimespec.tv_nsec ){ - return SQLITE_BUSY; - } - - if( nTries==2 ){ - char tBuf[PROXY_MAXCONCHLEN]; - int len = osPread(conchFile->h, tBuf, PROXY_MAXCONCHLEN, 0); - if( len<0 ){ - storeLastErrno(pFile, errno); - return SQLITE_IOERR_LOCK; - } - if( len>PROXY_PATHINDEX && tBuf[0]==(char)PROXY_CONCHVERSION){ - /* don't break the lock if the host id doesn't match */ - if( 0!=memcmp(&tBuf[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN) ){ - return SQLITE_BUSY; - } - }else{ - /* don't break the lock on short read or a version mismatch */ - return SQLITE_BUSY; - } - usleep(10000000); /* wait 10 sec and try the lock again */ - continue; - } - - assert( nTries==3 ); - if( 0==proxyBreakConchLock(pFile, myHostID) ){ - rc = SQLITE_OK; - if( lockType==EXCLUSIVE_LOCK ){ - rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, SHARED_LOCK); - } - if( !rc ){ - rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType); - } - } - } - } while( rc==SQLITE_BUSY && nTries<3 ); - - return rc; -} - -/* Takes the conch by taking a shared lock and read the contents conch, if -** lockPath is non-NULL, the host ID and lock file path must match. A NULL -** lockPath means that the lockPath in the conch file will be used if the -** host IDs match, or a new lock path will be generated automatically -** and written to the conch file. -*/ -static int proxyTakeConch(unixFile *pFile){ - proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; - - if( pCtx->conchHeld!=0 ){ - return SQLITE_OK; - }else{ - unixFile *conchFile = pCtx->conchFile; - uuid_t myHostID; - int pError = 0; - char readBuf[PROXY_MAXCONCHLEN]; - char lockPath[MAXPATHLEN]; - char *tempLockPath = NULL; - int rc = SQLITE_OK; - int createConch = 0; - int hostIdMatch = 0; - int readLen = 0; - int tryOldLockPath = 0; - int forceNewLockPath = 0; - - OSTRACE(("TAKECONCH %d for %s pid=%d\n", conchFile->h, - (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), - osGetpid(0))); - - rc = proxyGetHostID(myHostID, &pError); - if( (rc&0xff)==SQLITE_IOERR ){ - storeLastErrno(pFile, pError); - goto end_takeconch; - } - rc = proxyConchLock(pFile, myHostID, SHARED_LOCK); - if( rc!=SQLITE_OK ){ - goto end_takeconch; - } - /* read the existing conch file */ - readLen = seekAndRead((unixFile*)conchFile, 0, readBuf, PROXY_MAXCONCHLEN); - if( readLen<0 ){ - /* I/O error: lastErrno set by seekAndRead */ - storeLastErrno(pFile, conchFile->lastErrno); - rc = SQLITE_IOERR_READ; - goto end_takeconch; - }else if( readLen<=(PROXY_HEADERLEN+PROXY_HOSTIDLEN) || - readBuf[0]!=(char)PROXY_CONCHVERSION ){ - /* a short read or version format mismatch means we need to create a new - ** conch file. - */ - createConch = 1; - } - /* if the host id matches and the lock path already exists in the conch - ** we'll try to use the path there, if we can't open that path, we'll - ** retry with a new auto-generated path - */ - do { /* in case we need to try again for an :auto: named lock file */ - - if( !createConch && !forceNewLockPath ){ - hostIdMatch = !memcmp(&readBuf[PROXY_HEADERLEN], myHostID, - PROXY_HOSTIDLEN); - /* if the conch has data compare the contents */ - if( !pCtx->lockProxyPath ){ - /* for auto-named local lock file, just check the host ID and we'll - ** use the local lock file path that's already in there - */ - if( hostIdMatch ){ - size_t pathLen = (readLen - PROXY_PATHINDEX); - - if( pathLen>=MAXPATHLEN ){ - pathLen=MAXPATHLEN-1; - } - memcpy(lockPath, &readBuf[PROXY_PATHINDEX], pathLen); - lockPath[pathLen] = 0; - tempLockPath = lockPath; - tryOldLockPath = 1; - /* create a copy of the lock path if the conch is taken */ - goto end_takeconch; - } - }else if( hostIdMatch - && !strncmp(pCtx->lockProxyPath, &readBuf[PROXY_PATHINDEX], - readLen-PROXY_PATHINDEX) - ){ - /* conch host and lock path match */ - goto end_takeconch; - } - } - - /* if the conch isn't writable and doesn't match, we can't take it */ - if( (conchFile->openFlags&O_RDWR) == 0 ){ - rc = SQLITE_BUSY; - goto end_takeconch; - } - - /* either the conch didn't match or we need to create a new one */ - if( !pCtx->lockProxyPath ){ - proxyGetLockPath(pCtx->dbPath, lockPath, MAXPATHLEN); - tempLockPath = lockPath; - /* create a copy of the lock path _only_ if the conch is taken */ - } - - /* update conch with host and path (this will fail if other process - ** has a shared lock already), if the host id matches, use the big - ** stick. - */ - futimes(conchFile->h, NULL); - if( hostIdMatch && !createConch ){ - if( conchFile->pInode && conchFile->pInode->nShared>1 ){ - /* We are trying for an exclusive lock but another thread in this - ** same process is still holding a shared lock. */ - rc = SQLITE_BUSY; - } else { - rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK); - } - }else{ - rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK); - } - if( rc==SQLITE_OK ){ - char writeBuffer[PROXY_MAXCONCHLEN]; - int writeSize = 0; - - writeBuffer[0] = (char)PROXY_CONCHVERSION; - memcpy(&writeBuffer[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN); - if( pCtx->lockProxyPath!=NULL ){ - strlcpy(&writeBuffer[PROXY_PATHINDEX], pCtx->lockProxyPath, - MAXPATHLEN); - }else{ - strlcpy(&writeBuffer[PROXY_PATHINDEX], tempLockPath, MAXPATHLEN); - } - writeSize = PROXY_PATHINDEX + strlen(&writeBuffer[PROXY_PATHINDEX]); - robust_ftruncate(conchFile->h, writeSize); - rc = unixWrite((sqlite3_file *)conchFile, writeBuffer, writeSize, 0); - fsync(conchFile->h); - /* If we created a new conch file (not just updated the contents of a - ** valid conch file), try to match the permissions of the database - */ - if( rc==SQLITE_OK && createConch ){ - struct stat buf; - int err = osFstat(pFile->h, &buf); - if( err==0 ){ - mode_t cmode = buf.st_mode&(S_IRUSR|S_IWUSR | S_IRGRP|S_IWGRP | - S_IROTH|S_IWOTH); - /* try to match the database file R/W permissions, ignore failure */ -#ifndef SQLITE_PROXY_DEBUG - osFchmod(conchFile->h, cmode); -#else - do{ - rc = osFchmod(conchFile->h, cmode); - }while( rc==(-1) && errno==EINTR ); - if( rc!=0 ){ - int code = errno; - fprintf(stderr, "fchmod %o FAILED with %d %s\n", - cmode, code, strerror(code)); - } else { - fprintf(stderr, "fchmod %o SUCCEDED\n",cmode); - } - }else{ - int code = errno; - fprintf(stderr, "STAT FAILED[%d] with %d %s\n", - err, code, strerror(code)); -#endif - } - } - } - conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, SHARED_LOCK); - - end_takeconch: - OSTRACE(("TRANSPROXY: CLOSE %d\n", pFile->h)); - if( rc==SQLITE_OK && pFile->openFlags ){ - int fd; - if( pFile->h>=0 ){ - robust_close(pFile, pFile->h, __LINE__); - } - pFile->h = -1; - fd = robust_open(pCtx->dbPath, pFile->openFlags, 0); - OSTRACE(("TRANSPROXY: OPEN %d\n", fd)); - if( fd>=0 ){ - pFile->h = fd; - }else{ - rc=SQLITE_CANTOPEN_BKPT; /* SQLITE_BUSY? proxyTakeConch called - during locking */ - } - } - if( rc==SQLITE_OK && !pCtx->lockProxy ){ - char *path = tempLockPath ? tempLockPath : pCtx->lockProxyPath; - rc = proxyCreateUnixFile(path, &pCtx->lockProxy, 1); - if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM && tryOldLockPath ){ - /* we couldn't create the proxy lock file with the old lock file path - ** so try again via auto-naming - */ - forceNewLockPath = 1; - tryOldLockPath = 0; - continue; /* go back to the do {} while start point, try again */ - } - } - if( rc==SQLITE_OK ){ - /* Need to make a copy of path if we extracted the value - ** from the conch file or the path was allocated on the stack - */ - if( tempLockPath ){ - pCtx->lockProxyPath = sqlite3DbStrDup(0, tempLockPath); - if( !pCtx->lockProxyPath ){ - rc = SQLITE_NOMEM; - } - } - } - if( rc==SQLITE_OK ){ - pCtx->conchHeld = 1; - - if( pCtx->lockProxy->pMethod == &afpIoMethods ){ - afpLockingContext *afpCtx; - afpCtx = (afpLockingContext *)pCtx->lockProxy->lockingContext; - afpCtx->dbPath = pCtx->lockProxyPath; - } - } else { - conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK); - } - OSTRACE(("TAKECONCH %d %s\n", conchFile->h, - rc==SQLITE_OK?"ok":"failed")); - return rc; - } while (1); /* in case we need to retry the :auto: lock file - - ** we should never get here except via the 'continue' call. */ - } -} - -/* -** If pFile holds a lock on a conch file, then release that lock. -*/ -static int proxyReleaseConch(unixFile *pFile){ - int rc = SQLITE_OK; /* Subroutine return code */ - proxyLockingContext *pCtx; /* The locking context for the proxy lock */ - unixFile *conchFile; /* Name of the conch file */ - - pCtx = (proxyLockingContext *)pFile->lockingContext; - conchFile = pCtx->conchFile; - OSTRACE(("RELEASECONCH %d for %s pid=%d\n", conchFile->h, - (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), - osGetpid(0))); - if( pCtx->conchHeld>0 ){ - rc = conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK); - } - pCtx->conchHeld = 0; - OSTRACE(("RELEASECONCH %d %s\n", conchFile->h, - (rc==SQLITE_OK ? "ok" : "failed"))); - return rc; -} - -/* -** Given the name of a database file, compute the name of its conch file. -** Store the conch filename in memory obtained from sqlite3_malloc64(). -** Make *pConchPath point to the new name. Return SQLITE_OK on success -** or SQLITE_NOMEM if unable to obtain memory. -** -** The caller is responsible for ensuring that the allocated memory -** space is eventually freed. -** -** *pConchPath is set to NULL if a memory allocation error occurs. -*/ -static int proxyCreateConchPathname(char *dbPath, char **pConchPath){ - int i; /* Loop counter */ - int len = (int)strlen(dbPath); /* Length of database filename - dbPath */ - char *conchPath; /* buffer in which to construct conch name */ - - /* Allocate space for the conch filename and initialize the name to - ** the name of the original database file. */ - *pConchPath = conchPath = (char *)sqlite3_malloc64(len + 8); - if( conchPath==0 ){ - return SQLITE_NOMEM; - } - memcpy(conchPath, dbPath, len+1); - - /* now insert a "." before the last / character */ - for( i=(len-1); i>=0; i-- ){ - if( conchPath[i]=='/' ){ - i++; - break; - } - } - conchPath[i]='.'; - while ( i<len ){ - conchPath[i+1]=dbPath[i]; - i++; - } - - /* append the "-conch" suffix to the file */ - memcpy(&conchPath[i+1], "-conch", 7); - assert( (int)strlen(conchPath) == len+7 ); - - return SQLITE_OK; -} - - -/* Takes a fully configured proxy locking-style unix file and switches -** the local lock file path -*/ -static int switchLockProxyPath(unixFile *pFile, const char *path) { - proxyLockingContext *pCtx = (proxyLockingContext*)pFile->lockingContext; - char *oldPath = pCtx->lockProxyPath; - int rc = SQLITE_OK; - - if( pFile->eFileLock!=NO_LOCK ){ - return SQLITE_BUSY; - } - - /* nothing to do if the path is NULL, :auto: or matches the existing path */ - if( !path || path[0]=='\0' || !strcmp(path, ":auto:") || - (oldPath && !strncmp(oldPath, path, MAXPATHLEN)) ){ - return SQLITE_OK; - }else{ - unixFile *lockProxy = pCtx->lockProxy; - pCtx->lockProxy=NULL; - pCtx->conchHeld = 0; - if( lockProxy!=NULL ){ - rc=lockProxy->pMethod->xClose((sqlite3_file *)lockProxy); - if( rc ) return rc; - sqlite3_free(lockProxy); - } - sqlite3_free(oldPath); - pCtx->lockProxyPath = sqlite3DbStrDup(0, path); - } - - return rc; -} - -/* -** pFile is a file that has been opened by a prior xOpen call. dbPath -** is a string buffer at least MAXPATHLEN+1 characters in size. -** -** This routine find the filename associated with pFile and writes it -** int dbPath. -*/ -static int proxyGetDbPathForUnixFile(unixFile *pFile, char *dbPath){ -#if defined(__APPLE__) - if( pFile->pMethod == &afpIoMethods ){ - /* afp style keeps a reference to the db path in the filePath field - ** of the struct */ - assert( (int)strlen((char*)pFile->lockingContext)<=MAXPATHLEN ); - strlcpy(dbPath, ((afpLockingContext *)pFile->lockingContext)->dbPath, - MAXPATHLEN); - } else -#endif - if( pFile->pMethod == &dotlockIoMethods ){ - /* dot lock style uses the locking context to store the dot lock - ** file path */ - int len = strlen((char *)pFile->lockingContext) - strlen(DOTLOCK_SUFFIX); - memcpy(dbPath, (char *)pFile->lockingContext, len + 1); - }else{ - /* all other styles use the locking context to store the db file path */ - assert( strlen((char*)pFile->lockingContext)<=MAXPATHLEN ); - strlcpy(dbPath, (char *)pFile->lockingContext, MAXPATHLEN); - } - return SQLITE_OK; -} - -/* -** Takes an already filled in unix file and alters it so all file locking -** will be performed on the local proxy lock file. The following fields -** are preserved in the locking context so that they can be restored and -** the unix structure properly cleaned up at close time: -** ->lockingContext -** ->pMethod -*/ -static int proxyTransformUnixFile(unixFile *pFile, const char *path) { - proxyLockingContext *pCtx; - char dbPath[MAXPATHLEN+1]; /* Name of the database file */ - char *lockPath=NULL; - int rc = SQLITE_OK; - - if( pFile->eFileLock!=NO_LOCK ){ - return SQLITE_BUSY; - } - proxyGetDbPathForUnixFile(pFile, dbPath); - if( !path || path[0]=='\0' || !strcmp(path, ":auto:") ){ - lockPath=NULL; - }else{ - lockPath=(char *)path; - } - - OSTRACE(("TRANSPROXY %d for %s pid=%d\n", pFile->h, - (lockPath ? lockPath : ":auto:"), osGetpid(0))); - - pCtx = sqlite3_malloc64( sizeof(*pCtx) ); - if( pCtx==0 ){ - return SQLITE_NOMEM; - } - memset(pCtx, 0, sizeof(*pCtx)); - - rc = proxyCreateConchPathname(dbPath, &pCtx->conchFilePath); - if( rc==SQLITE_OK ){ - rc = proxyCreateUnixFile(pCtx->conchFilePath, &pCtx->conchFile, 0); - if( rc==SQLITE_CANTOPEN && ((pFile->openFlags&O_RDWR) == 0) ){ - /* if (a) the open flags are not O_RDWR, (b) the conch isn't there, and - ** (c) the file system is read-only, then enable no-locking access. - ** Ugh, since O_RDONLY==0x0000 we test for !O_RDWR since unixOpen asserts - ** that openFlags will have only one of O_RDONLY or O_RDWR. - */ - struct statfs fsInfo; - struct stat conchInfo; - int goLockless = 0; - - if( osStat(pCtx->conchFilePath, &conchInfo) == -1 ) { - int err = errno; - if( (err==ENOENT) && (statfs(dbPath, &fsInfo) != -1) ){ - goLockless = (fsInfo.f_flags&MNT_RDONLY) == MNT_RDONLY; - } - } - if( goLockless ){ - pCtx->conchHeld = -1; /* read only FS/ lockless */ - rc = SQLITE_OK; - } - } - } - if( rc==SQLITE_OK && lockPath ){ - pCtx->lockProxyPath = sqlite3DbStrDup(0, lockPath); - } - - if( rc==SQLITE_OK ){ - pCtx->dbPath = sqlite3DbStrDup(0, dbPath); - if( pCtx->dbPath==NULL ){ - rc = SQLITE_NOMEM; - } - } - if( rc==SQLITE_OK ){ - /* all memory is allocated, proxys are created and assigned, - ** switch the locking context and pMethod then return. - */ - pCtx->oldLockingContext = pFile->lockingContext; - pFile->lockingContext = pCtx; - pCtx->pOldMethod = pFile->pMethod; - pFile->pMethod = &proxyIoMethods; - }else{ - if( pCtx->conchFile ){ - pCtx->conchFile->pMethod->xClose((sqlite3_file *)pCtx->conchFile); - sqlite3_free(pCtx->conchFile); - } - sqlite3DbFree(0, pCtx->lockProxyPath); - sqlite3_free(pCtx->conchFilePath); - sqlite3_free(pCtx); - } - OSTRACE(("TRANSPROXY %d %s\n", pFile->h, - (rc==SQLITE_OK ? "ok" : "failed"))); - return rc; -} - - -/* -** This routine handles sqlite3_file_control() calls that are specific -** to proxy locking. -*/ -static int proxyFileControl(sqlite3_file *id, int op, void *pArg){ - switch( op ){ - case SQLITE_FCNTL_GET_LOCKPROXYFILE: { - unixFile *pFile = (unixFile*)id; - if( pFile->pMethod == &proxyIoMethods ){ - proxyLockingContext *pCtx = (proxyLockingContext*)pFile->lockingContext; - proxyTakeConch(pFile); - if( pCtx->lockProxyPath ){ - *(const char **)pArg = pCtx->lockProxyPath; - }else{ - *(const char **)pArg = ":auto: (not held)"; - } - } else { - *(const char **)pArg = NULL; - } - return SQLITE_OK; - } - case SQLITE_FCNTL_SET_LOCKPROXYFILE: { - unixFile *pFile = (unixFile*)id; - int rc = SQLITE_OK; - int isProxyStyle = (pFile->pMethod == &proxyIoMethods); - if( pArg==NULL || (const char *)pArg==0 ){ - if( isProxyStyle ){ - /* turn off proxy locking - not supported. If support is added for - ** switching proxy locking mode off then it will need to fail if - ** the journal mode is WAL mode. - */ - rc = SQLITE_ERROR /*SQLITE_PROTOCOL? SQLITE_MISUSE?*/; - }else{ - /* turn off proxy locking - already off - NOOP */ - rc = SQLITE_OK; - } - }else{ - const char *proxyPath = (const char *)pArg; - if( isProxyStyle ){ - proxyLockingContext *pCtx = - (proxyLockingContext*)pFile->lockingContext; - if( !strcmp(pArg, ":auto:") - || (pCtx->lockProxyPath && - !strncmp(pCtx->lockProxyPath, proxyPath, MAXPATHLEN)) - ){ - rc = SQLITE_OK; - }else{ - rc = switchLockProxyPath(pFile, proxyPath); - } - }else{ - /* turn on proxy file locking */ - rc = proxyTransformUnixFile(pFile, proxyPath); - } - } - return rc; - } - default: { - assert( 0 ); /* The call assures that only valid opcodes are sent */ - } - } - /*NOTREACHED*/ - return SQLITE_ERROR; -} - -/* -** Within this division (the proxying locking implementation) the procedures -** above this point are all utilities. The lock-related methods of the -** proxy-locking sqlite3_io_method object follow. -*/ - - -/* -** This routine checks if there is a RESERVED lock held on the specified -** file by this or any other process. If such a lock is held, set *pResOut -** to a non-zero value otherwise *pResOut is set to zero. The return value -** is set to SQLITE_OK unless an I/O error occurs during lock checking. -*/ -static int proxyCheckReservedLock(sqlite3_file *id, int *pResOut) { - unixFile *pFile = (unixFile*)id; - int rc = proxyTakeConch(pFile); - if( rc==SQLITE_OK ){ - proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; - if( pCtx->conchHeld>0 ){ - unixFile *proxy = pCtx->lockProxy; - return proxy->pMethod->xCheckReservedLock((sqlite3_file*)proxy, pResOut); - }else{ /* conchHeld < 0 is lockless */ - pResOut=0; - } - } - return rc; -} - -/* -** Lock the file with the lock specified by parameter eFileLock - one -** of the following: -** -** (1) SHARED_LOCK -** (2) RESERVED_LOCK -** (3) PENDING_LOCK -** (4) EXCLUSIVE_LOCK -** -** Sometimes when requesting one lock state, additional lock states -** are inserted in between. The locking might fail on one of the later -** transitions leaving the lock state different from what it started but -** still short of its goal. The following chart shows the allowed -** transitions and the inserted intermediate states: -** -** UNLOCKED -> SHARED -** SHARED -> RESERVED -** SHARED -> (PENDING) -> EXCLUSIVE -** RESERVED -> (PENDING) -> EXCLUSIVE -** PENDING -> EXCLUSIVE -** -** This routine will only increase a lock. Use the sqlite3OsUnlock() -** routine to lower a locking level. -*/ -static int proxyLock(sqlite3_file *id, int eFileLock) { - unixFile *pFile = (unixFile*)id; - int rc = proxyTakeConch(pFile); - if( rc==SQLITE_OK ){ - proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; - if( pCtx->conchHeld>0 ){ - unixFile *proxy = pCtx->lockProxy; - rc = proxy->pMethod->xLock((sqlite3_file*)proxy, eFileLock); - pFile->eFileLock = proxy->eFileLock; - }else{ - /* conchHeld < 0 is lockless */ - } - } - return rc; -} - - -/* -** Lower the locking level on file descriptor pFile to eFileLock. eFileLock -** must be either NO_LOCK or SHARED_LOCK. -** -** If the locking level of the file descriptor is already at or below -** the requested locking level, this routine is a no-op. -*/ -static int proxyUnlock(sqlite3_file *id, int eFileLock) { - unixFile *pFile = (unixFile*)id; - int rc = proxyTakeConch(pFile); - if( rc==SQLITE_OK ){ - proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; - if( pCtx->conchHeld>0 ){ - unixFile *proxy = pCtx->lockProxy; - rc = proxy->pMethod->xUnlock((sqlite3_file*)proxy, eFileLock); - pFile->eFileLock = proxy->eFileLock; - }else{ - /* conchHeld < 0 is lockless */ - } - } - return rc; -} - -/* -** Close a file that uses proxy locks. -*/ -static int proxyClose(sqlite3_file *id) { - if( id ){ - unixFile *pFile = (unixFile*)id; - proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; - unixFile *lockProxy = pCtx->lockProxy; - unixFile *conchFile = pCtx->conchFile; - int rc = SQLITE_OK; - - if( lockProxy ){ - rc = lockProxy->pMethod->xUnlock((sqlite3_file*)lockProxy, NO_LOCK); - if( rc ) return rc; - rc = lockProxy->pMethod->xClose((sqlite3_file*)lockProxy); - if( rc ) return rc; - sqlite3_free(lockProxy); - pCtx->lockProxy = 0; - } - if( conchFile ){ - if( pCtx->conchHeld ){ - rc = proxyReleaseConch(pFile); - if( rc ) return rc; - } - rc = conchFile->pMethod->xClose((sqlite3_file*)conchFile); - if( rc ) return rc; - sqlite3_free(conchFile); - } - sqlite3DbFree(0, pCtx->lockProxyPath); - sqlite3_free(pCtx->conchFilePath); - sqlite3DbFree(0, pCtx->dbPath); - /* restore the original locking context and pMethod then close it */ - pFile->lockingContext = pCtx->oldLockingContext; - pFile->pMethod = pCtx->pOldMethod; - sqlite3_free(pCtx); - return pFile->pMethod->xClose(id); - } - return SQLITE_OK; -} - - - -#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */ -/* -** The proxy locking style is intended for use with AFP filesystems. -** And since AFP is only supported on MacOSX, the proxy locking is also -** restricted to MacOSX. -** -** -******************* End of the proxy lock implementation ********************** -******************************************************************************/ - -/* -** Initialize the operating system interface. -** -** This routine registers all VFS implementations for unix-like operating -** systems. This routine, and the sqlite3_os_end() routine that follows, -** should be the only routines in this file that are visible from other -** files. -** -** This routine is called once during SQLite initialization and by a -** single thread. The memory allocation and mutex subsystems have not -** necessarily been initialized when this routine is called, and so they -** should not be used. -*/ -int sqlite3_os_init(void){ - /* - ** The following macro defines an initializer for an sqlite3_vfs object. - ** The name of the VFS is NAME. The pAppData is a pointer to a pointer - ** to the "finder" function. (pAppData is a pointer to a pointer because - ** silly C90 rules prohibit a void* from being cast to a function pointer - ** and so we have to go through the intermediate pointer to avoid problems - ** when compiling with -pedantic-errors on GCC.) - ** - ** The FINDER parameter to this macro is the name of the pointer to the - ** finder-function. The finder-function returns a pointer to the - ** sqlite_io_methods object that implements the desired locking - ** behaviors. See the division above that contains the IOMETHODS - ** macro for addition information on finder-functions. - ** - ** Most finders simply return a pointer to a fixed sqlite3_io_methods - ** object. But the "autolockIoFinder" available on MacOSX does a little - ** more than that; it looks at the filesystem type that hosts the - ** database file and tries to choose an locking method appropriate for - ** that filesystem time. - */ - #define UNIXVFS(VFSNAME, FINDER) { \ - 3, /* iVersion */ \ - sizeof(unixFile), /* szOsFile */ \ - MAX_PATHNAME, /* mxPathname */ \ - 0, /* pNext */ \ - VFSNAME, /* zName */ \ - (void*)&FINDER, /* pAppData */ \ - unixOpen, /* xOpen */ \ - unixDelete, /* xDelete */ \ - unixAccess, /* xAccess */ \ - unixFullPathname, /* xFullPathname */ \ - unixDlOpen, /* xDlOpen */ \ - unixDlError, /* xDlError */ \ - unixDlSym, /* xDlSym */ \ - unixDlClose, /* xDlClose */ \ - unixRandomness, /* xRandomness */ \ - unixSleep, /* xSleep */ \ - unixCurrentTime, /* xCurrentTime */ \ - unixGetLastError, /* xGetLastError */ \ - unixCurrentTimeInt64, /* xCurrentTimeInt64 */ \ - unixSetSystemCall, /* xSetSystemCall */ \ - unixGetSystemCall, /* xGetSystemCall */ \ - unixNextSystemCall, /* xNextSystemCall */ \ - } - - /* - ** All default VFSes for unix are contained in the following array. - ** - ** Note that the sqlite3_vfs.pNext field of the VFS object is modified - ** by the SQLite core when the VFS is registered. So the following - ** array cannot be const. - */ - static sqlite3_vfs aVfs[] = { -#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) - UNIXVFS("unix", autolockIoFinder ), -#elif OS_VXWORKS - UNIXVFS("unix", vxworksIoFinder ), -#else - UNIXVFS("unix", posixIoFinder ), -#endif - UNIXVFS("unix-none", nolockIoFinder ), - UNIXVFS("unix-dotfile", dotlockIoFinder ), - UNIXVFS("unix-excl", posixIoFinder ), -#if OS_VXWORKS - UNIXVFS("unix-namedsem", semIoFinder ), -#endif -#if SQLITE_ENABLE_LOCKING_STYLE || OS_VXWORKS - UNIXVFS("unix-posix", posixIoFinder ), -#endif -#if SQLITE_ENABLE_LOCKING_STYLE - UNIXVFS("unix-flock", flockIoFinder ), -#endif -#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) - UNIXVFS("unix-afp", afpIoFinder ), - UNIXVFS("unix-nfs", nfsIoFinder ), - UNIXVFS("unix-proxy", proxyIoFinder ), -#endif - }; - unsigned int i; /* Loop counter */ - - /* Double-check that the aSyscall[] array has been constructed - ** correctly. See ticket [bb3a86e890c8e96ab] */ - assert( ArraySize(aSyscall)==25 ); - - /* Register all VFSes defined in the aVfs[] array */ - for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){ - sqlite3_vfs_register(&aVfs[i], i==0); - } - return SQLITE_OK; -} - -/* -** Shutdown the operating system interface. -** -** Some operating systems might need to do some cleanup in this routine, -** to release dynamically allocated objects. But not on unix. -** This routine is a no-op for unix. -*/ -int sqlite3_os_end(void){ - return SQLITE_OK; -} - -#endif /* SQLITE_OS_UNIX */ |