KVM: SVM: Mark VMCB_LBR dirty when MSR_IA32_DEBUGCTLMSR is updated - wireguard-linux

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author	Yosry Ahmed <yosry.ahmed@linux.dev>	2025-11-08 00:45:19 +0000
committer	Paolo Bonzini <pbonzini@redhat.com>	2025-11-09 08:49:48 +0100
commit	dc55b3c3f61246e483e50c85d8d5366f9567e188 (patch)
tree	94b3d5c28d3a2bb02076c1d01e0c80584effe0f3 /drivers/mca/git:/ssh:/git@git.zx2c4.com
parent	Merge tag 'kvmarm-fixes-6.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD (diff)

KVM: SVM: Mark VMCB_LBR dirty when MSR_IA32_DEBUGCTLMSR is updated

The APM lists the DbgCtlMsr field as being tracked by the VMCB_LBR clean bit. Always clear the bit when MSR_IA32_DEBUGCTLMSR is updated. The history is complicated, it was correctly cleared for L1 before commit 1d5a1b5860ed ("KVM: x86: nSVM: correctly virtualize LBR msrs when L2 is running"). At that point svm_set_msr() started to rely on svm_update_lbrv() to clear the bit, but when nested virtualization is enabled the latter does not always clear it even if MSR_IA32_DEBUGCTLMSR changed. Go back to clearing it directly in svm_set_msr(). Fixes: 1d5a1b5860ed ("KVM: x86: nSVM: correctly virtualize LBR msrs when L2 is running") Reported-by: Matteo Rizzo <matteorizzo@google.com> Reported-by: evn@google.com Co-developed-by: Jim Mattson <jmattson@google.com> Signed-off-by: Jim Mattson <jmattson@google.com> Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev> Link: https://patch.msgid.link/20251108004524.1600006-2-yosry.ahmed@linux.dev Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Diffstat (limited to 'drivers/mca/git:/ssh:/git@git.zx2c4.com')

0 files changed, 0 insertions, 0 deletions

/* Run time dynamic linker. Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include <link.h> #include <stddef.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/mman.h> /* Check if MAP_ANON is defined. */ #include <stdio-common/_itoa.h> #include <assert.h> #include <entry.h> #include "dynamic-link.h" /* System-specific function to do initial startup for the dynamic linker. After this, file access calls and getenv must work. This is responsible for setting __libc_enable_secure if we need to be secure (e.g. setuid), and for setting _dl_argc and _dl_argv, and then calling _dl_main. */ extern ElfW(Addr) _dl_sysdep_start (void **start_argptr, void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Half) phent, ElfW(Addr) *user_entry)); extern void _dl_sysdep_start_cleanup (void); /* System-dependent function to read a file's whole contents in the most convenient manner available. */ extern void *_dl_sysdep_read_whole_file (const char *filename, size_t *filesize_ptr, int mmap_prot); /* Helper function to handle errors while resolving symbols. */ static void print_unresolved (int errcode, const char *objname, const char *errsting); /* Helper function to handle errors when a version is missing. */ static void print_missing_version (int errcode, const char *objname, const char *errsting); /* This is a list of all the modes the dynamic loader can be in. */ enum mode { normal, list, verify, trace }; /* Process all environments variables the dynamic linker must recognize. Since all of them start with `LD_' we are a bit smarter while finding all the entries. */ static void process_envvars (enum mode *modep, int *lazyp); int _dl_argc; char **_dl_argv; const char *_dl_rpath; int _dl_verbose; const char *_dl_platform; size_t _dl_platformlen; unsigned long _dl_hwcap; struct r_search_path *_dl_search_paths; const char *_dl_profile; const char *_dl_profile_output; struct link_map *_dl_profile_map; int _dl_debug_libs; /* Set nonzero during loading and initialization of executable and libraries, cleared before the executable's entry point runs. This must not be initialized to nonzero, because the unused dynamic linker loaded in for libc.so's "ld.so.1" dep will provide the definition seen by libc.so's initializer; that value must be zero, and will be since that dynamic linker's _dl_start and dl_main will never be called. */ int _dl_starting_up; static void dl_main (const ElfW(Phdr) *phdr, ElfW(Half) phent, ElfW(Addr) *user_entry); struct link_map _dl_rtld_map; struct libname_list _dl_rtld_libname; struct libname_list _dl_rtld_libname2; #ifdef RTLD_START RTLD_START #else #error "sysdeps/MACHINE/dl-machine.h fails to define RTLD_START" #endif static ElfW(Addr) _dl_start (void *arg) { struct link_map bootstrap_map; /* This #define produces dynamic linking inline functions for bootstrap relocation instead of general-purpose relocation. */ #define RTLD_BOOTSTRAP #define RESOLVE(sym, version, flags) bootstrap_map.l_addr #include "dynamic-link.h" /* Figure out the run-time load address of the dynamic linker itself. */ bootstrap_map.l_addr = elf_machine_load_address (); /* Read our own dynamic section and fill in the info array. */ bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + elf_machine_dynamic (); elf_get_dynamic_info (bootstrap_map.l_ld, bootstrap_map.l_info); #ifdef ELF_MACHINE_BEFORE_RTLD_RELOC ELF_MACHINE_BEFORE_RTLD_RELOC (bootstrap_map.l_info); #endif /* Relocate ourselves so we can do normal function calls and data access using the global offset table. */ ELF_DYNAMIC_RELOCATE (&bootstrap_map, 0, 0); /* Please note that we don't allow profiling of this object and therefore need not test whether we have to allocate the array for the relocation results (as done in dl-reloc.c). */ /* Now life is sane; we can call functions and access global data. Set up to use the operating system facilities, and find out from the operating system's program loader where to find the program header table in core. */ /* Transfer data about ourselves to the permanent link_map structure. */ _dl_rtld_map.l_addr = bootstrap_map.l_addr; _dl_rtld_map.l_ld = bootstrap_map.l_ld; _dl_rtld_map.l_opencount = 1; memcpy (_dl_rtld_map.l_info, bootstrap_map.l_info, sizeof _dl_rtld_map.l_info); _dl_setup_hash (&_dl_rtld_map); /* Cache the DT_RPATH stored in ld.so itself; this will be the default search path. */ if (_dl_rtld_map.l_info[DT_STRTAB] && _dl_rtld_map.l_info[DT_RPATH]) { _dl_rpath = (void *) (_dl_rtld_map.l_addr + _dl_rtld_map.l_info[DT_STRTAB]->d_un.d_ptr + _dl_rtld_map.l_info[DT_RPATH]->d_un.d_val); } /* Call the OS-dependent function to set up life so we can do things like file access. It will call `dl_main' (below) to do all the real work of the dynamic linker, and then unwind our frame and run the user entry point on the same stack we entered on. */ return _dl_sysdep_start (arg, &dl_main); } /* Now life is peachy; we can do all normal operations. On to the real work. */ void ENTRY_POINT (void); /* Some helper functions. */ /* Arguments to relocate_doit. */ struct relocate_args { struct link_map *l; int lazy; }; struct map_args { /* Argument to map_doit. */ char *str; /* Return value of map_doit. */ struct link_map *main_map; }; /* Arguments to version_check_doit. */ struct version_check_args { struct link_map *main_map; int doexit; }; static void relocate_doit (void *a) { struct relocate_args *args = (struct relocate_args *) a; _dl_relocate_object (args->l, _dl_object_relocation_scope (args->l), args->lazy); } static void map_doit (void *a) { struct map_args *args = (struct map_args *)a; args->main_map = _dl_map_object (NULL, args->str, 0, lt_library, 0); } static void version_check_doit (void *a) { struct version_check_args *args = (struct version_check_args *)a; if (_dl_check_all_versions (args->main_map, 1) && args->doexit) /* We cannot start the application. Abort now. */ _exit (1); } static inline struct link_map * find_needed (const char *name) { unsigned int n; for (n = 0; n < _dl_loaded->l_nsearchlist; ++n) if (_dl_name_match_p (name, _dl_loaded->l_searchlist[n])) return _dl_loaded->l_searchlist[n]; /* Should never happen. */ return NULL; } static int match_version (const char *string, struct link_map *map) { const char *strtab = (const char *) (map->l_addr + map->l_info[DT_STRTAB]->d_un.d_ptr); ElfW(Verdef) *def; #define VERDEFTAG (DT_NUM + DT_PROCNUM + DT_VERSIONTAGIDX (DT_VERDEF)) if (map->l_info[VERDEFTAG] == NULL) /* The file has no symbol versioning. */ return 0; def = (ElfW(Verdef) *) ((char *) map->l_addr + map->l_info[VERDEFTAG]->d_un.d_ptr); while (1) { ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) def + def->vd_aux); /* Compare the version strings. */ if (strcmp (string, strtab + aux->vda_name) == 0) /* Bingo! */ return 1; /* If no more definitions we failed to find what we want. */ if (def->vd_next == 0) break; /* Next definition. */ def = (ElfW(Verdef) *) ((char *) def + def->vd_next); } return 0; } unsigned int _dl_skip_args; /* Nonzero if we were run directly. */ static void dl_main (const ElfW(Phdr) *phdr, ElfW(Half) phent, ElfW(Addr) *user_entry) { const ElfW(Phdr) *ph; struct link_map *main_map; int lazy; enum mode mode; struct link_map **preloads; unsigned int npreloads; const char *preloadlist; size_t file_size; char *file; int has_interp = 0; /* Process the environment variable which control the behaviour. */ process_envvars (&mode, &lazy); /* Set up a flag which tells we are just starting. */ _dl_starting_up = 1; if (*user_entry == (ElfW(Addr)) &ENTRY_POINT) { /* Ho ho. We are not the program interpreter! We are the program itself! This means someone ran ld.so as a command. Well, that might be convenient to do sometimes. We support it by interpreting the args like this: ld.so PROGRAM ARGS... The first argument is the name of a file containing an ELF executable we will load and run with the following arguments. To simplify life here, PROGRAM is searched for using the normal rules for shared objects, rather than $PATH or anything like that. We just load it and use its entry point; we don't pay attention to its PT_INTERP command (we are the interpreter ourselves). This is an easy way to test a new ld.so before installing it. */ /* Overwrites LD_LIBRARY_PATH if given. */ const char *library_path = NULL; /* Note the place where the dynamic linker actually came from. */ _dl_rtld_map.l_name = _dl_argv[0]; while (_dl_argc > 1) if (! strcmp (_dl_argv[1], "--list")) { mode = list; lazy = -1; /* This means do no dependency analysis. */ ++_dl_skip_args; --_dl_argc; ++_dl_argv; } else if (! strcmp (_dl_argv[1], "--verify")) { mode = verify; ++_dl_skip_args; --_dl_argc; ++_dl_argv; } else if (! strcmp (_dl_argv[1], "--library-path") && _dl_argc > 2) { library_path = _dl_argv[2]; _dl_skip_args += 2; _dl_argc -= 2; _dl_argv += 2; } else break; /* If we have no further argument the program was called incorrectly. Grant the user some education. */ if (_dl_argc < 2) _dl_sysdep_fatal ("\ Usage: ld.so [--list|--verify] EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\ You have invoked `ld.so', the helper program for shared library executables.\n\ This program usually lives in the file `/lib/ld.so', and special directives\n\ in executable files using ELF shared libraries tell the system's program\n\ loader to load the helper program from this file. This helper program loads\n\ the shared libraries needed by the program executable, prepares the program\n\ to run, and runs it. You may invoke this helper program directly from the\n\ command line to load and run an ELF executable file; this is like executing\n\ that file itself, but always uses this helper program from the file you\n\ specified, instead of the helper program file specified in the executable\n\ file you run. This is mostly of use for maintainers to test new versions\n\ of this helper program; chances are you did not intend to run this program.\n", NULL); ++_dl_skip_args; --_dl_argc; ++_dl_argv; /* Initialize the data structures for the search paths for shared objects. */ _dl_init_paths (library_path); if (mode == verify) { char *err_str = NULL; const char *obj_name __attribute__ ((unused)); struct map_args args; args.str = _dl_argv[0]; (void) _dl_catch_error (&err_str, &obj_name, map_doit, &args); main_map = args.main_map; if (err_str != NULL) { free (err_str); _exit (EXIT_FAILURE); } } else main_map = _dl_map_object (NULL, _dl_argv[0], 0, lt_library, 0); phdr = main_map->l_phdr; phent = main_map->l_phnum; main_map->l_name = (char *) ""; *user_entry = main_map->l_entry; } else { /* Create a link_map for the executable itself. This will be what dlopen on "" returns. */ main_map = _dl_new_object ((char *) "", "", lt_executable); if (main_map == NULL) _dl_sysdep_fatal ("cannot allocate memory for link map\n", NULL); main_map->l_phdr = phdr; main_map->l_phnum = phent; main_map->l_entry = *user_entry; main_map->l_opencount = 1; /* Initialize the data structures for the search paths for shared objects. */ _dl_init_paths (NULL); } /* Scan the program header table for the dynamic section. */ for (ph = phdr; ph < &phdr[phent]; ++ph) switch (ph->p_type) { case PT_PHDR: /* Find out the load address. */ main_map->l_addr = (ElfW(Addr)) phdr - ph->p_vaddr; break; case PT_DYNAMIC: /* This tells us where to find the dynamic section, which tells us everything we need to do. */ main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr; break; case PT_INTERP: /* This "interpreter segment" was used by the program loader to find the program interpreter, which is this program itself, the dynamic linker. We note what name finds us, so that a future dlopen call or DT_NEEDED entry, for something that wants to link against the dynamic linker as a shared library, will know that the shared object is already loaded. */ _dl_rtld_libname.name = (const char *) main_map->l_addr + ph->p_vaddr; _dl_rtld_libname.next = NULL; _dl_rtld_map.l_libname = &_dl_rtld_libname; /* Ordinarilly, we would get additional names for the loader from our DT_SONAME. This can't happen if we were actually linked as a static executable (detect this case when we have no DYNAMIC). If so, assume the filename component of the interpreter path to be our SONAME, and add it to our name list. */ if (_dl_rtld_map.l_ld == NULL) { char *p = strrchr (_dl_rtld_libname.name, '/'); if (p) { _dl_rtld_libname2.name = p+1; _dl_rtld_libname2.next = NULL; _dl_rtld_libname.next = &_dl_rtld_libname2; } } has_interp = 1; break; } if (! _dl_rtld_map.l_libname && _dl_rtld_map.l_name) { /* We were invoked directly, so the program might not have a PT_INTERP. */ _dl_rtld_libname.name = _dl_rtld_map.l_name; _dl_rtld_libname.next = NULL; _dl_rtld_map.l_libname = &_dl_rtld_libname; } else assert (_dl_rtld_map.l_libname); /* How else did we get here? */ if (mode == verify) /* We were called just to verify that this is a dynamic executable using us as the program interpreter. */ _exit (main_map->l_ld == NULL ? 1 : has_interp ? 0 : 2); /* Extract the contents of the dynamic section for easy access. */ elf_get_dynamic_info (main_map->l_ld, main_map->l_info); if (main_map->l_info[DT_HASH]) /* Set up our cache of pointers into the hash table. */ _dl_setup_hash (main_map); /* Put the link_map for ourselves on the chain so it can be found by name. Note that at this point the global chain of link maps contains exactly one element, which is pointed to by main_map. */ if (! _dl_rtld_map.l_name) /* If not invoked directly, the dynamic linker shared object file was found by the PT_INTERP name. */ _dl_rtld_map.l_name = (char *) _dl_rtld_map.l_libname->name; _dl_rtld_map.l_type = lt_library; main_map->l_next = &_dl_rtld_map; _dl_rtld_map.l_prev = main_map; /* We have two ways to specify objects to preload: via environment variable and via the file /etc/ld.so.preload. The later can also be used when security is enabled. */ preloads = NULL; npreloads = 0; preloadlist = getenv ("LD_PRELOAD"); if (preloadlist) { /* The LD_PRELOAD environment variable gives list of libraries separated by white space or colons that are loaded before the executable's dependencies and prepended to the global scope list. If the binary is running setuid all elements containing a '/' are ignored since it is insecure. */ char *list = strdupa (preloadlist); char *p; while ((p = strsep (&list, " :")) != NULL) if (! __libc_enable_secure || strchr (p, '/') == NULL) { struct link_map *new_map = _dl_map_object (NULL, p, 1, lt_library, 0); if (new_map->l_opencount == 1) /* It is no duplicate. */ ++npreloads; } } /* Read the contents of the file. */ file = _dl_sysdep_read_whole_file ("/etc/ld.so.preload", &file_size, PROT_READ | PROT_WRITE); if (file) { /* Parse the file. It contains names of libraries to be loaded, separated by white spaces or `:'. It may also contain comments introduced by `#'. */ char *problem; char *runp; size_t rest; /* Eliminate comments. */ runp = file; rest = file_size; while (rest > 0) { char *comment = memchr (runp, '#', rest); if (comment == NULL) break; rest -= comment - runp; do *comment = ' '; while (--rest > 0 && *++comment != '\n'); } /* We have one problematic case: if we have a name at the end of the file without a trailing terminating characters, we cannot place the \0. Handle the case separately. */ if (file[file_size - 1] != ' ' && file[file_size - 1] != '\t' && file[file_size - 1] != '\n' && file[file_size - 1] != ':') { problem = &file[file_size]; while (problem > file && problem[-1] != ' ' && problem[-1] != '\t' && problem[-1] != '\n' && problem[-1] != ':') --problem; if (problem > file) problem[-1] = '\0'; } else { problem = NULL; file[file_size - 1] = '\0'; } if (file != problem) { char *p; runp = file + strspn (file, ": \t\n"); while ((p = strsep (&runp, ": \t\n")) != NULL) { struct link_map *new_map = _dl_map_object (NULL, p, 1, lt_library, 0); if (new_map->l_opencount == 1) /* It is no duplicate. */ ++npreloads; if (runp != NULL) runp += strspn (runp, ": \t\n"); } } if (problem != NULL) { char *p = strndupa (problem, file_size - (problem - file)); struct link_map *new_map = _dl_map_object (NULL, p, 1, lt_library, 0); if (new_map->l_opencount == 1) /* It is no duplicate. */ ++npreloads; } /* We don't need the file anymore. */ __munmap (file, file_size); } if (npreloads != 0) { /* Set up PRELOADS with a vector of the preloaded libraries. */ struct link_map *l; unsigned int i; preloads = __alloca (npreloads * sizeof preloads[0]); l = _dl_rtld_map.l_next; /* End of the chain before preloads. */ i = 0; do { preloads[i++] = l; l = l->l_next; } while (l); assert (i == npreloads); } /* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD specified some libraries to load, these are inserted before the actual dependencies in the executable's searchlist for symbol resolution. */ _dl_map_object_deps (main_map, preloads, npreloads, mode == trace); #ifndef MAP_ANON /* We are done mapping things, so close the zero-fill descriptor. */ __close (_dl_zerofd); _dl_zerofd = -1; #endif /* Remove _dl_rtld_map from the chain. */ _dl_rtld_map.l_prev->l_next = _dl_rtld_map.l_next; if (_dl_rtld_map.l_next) _dl_rtld_map.l_next->l_prev = _dl_rtld_map.l_prev; if (_dl_rtld_map.l_opencount) { /* Some DT_NEEDED entry referred to the interpreter object itself, so put it back in the list of visible objects. We insert it into the chain in symbol search order because gdb uses the chain's order as its symbol search order. */ unsigned int i = 1; while (main_map->l_searchlist[i] != &_dl_rtld_map) ++i; _dl_rtld_map.l_prev = main_map->l_searchlist[i - 1]; _dl_rtld_map.l_next = (i + 1 < main_map->l_nsearchlist ? main_map->l_searchlist[i + 1] : NULL); assert (_dl_rtld_map.l_prev->l_next == _dl_rtld_map.l_next); _dl_rtld_map.l_prev->l_next = &_dl_rtld_map; if (_dl_rtld_map.l_next) { assert (_dl_rtld_map.l_next->l_prev == _dl_rtld_map.l_prev); _dl_rtld_map.l_next->l_prev = &_dl_rtld_map; } } /* Now let us see whether all libraries are available in the versions we need. */ { struct version_check_args args; args.doexit = mode == normal; args.main_map = main_map; _dl_receive_error (print_missing_version, version_check_doit, &args); } if (mode != normal) { /* We were run just to list the shared libraries. It is important that we do this before real relocation, because the functions we call below for output may no longer work properly after relocation. */ int i; if (! _dl_loaded->l_info[DT_NEEDED]) _dl_sysdep_message ("\t", "statically linked\n", NULL); else { struct link_map *l; for (l = _dl_loaded->l_next; l; l = l->l_next) if (l->l_opencount == 0) /* The library was not found. */ _dl_sysdep_message ("\t", l->l_libname->name, " => not found\n", NULL); else { char buf[20], *bp; buf[sizeof buf - 1] = '\0'; bp = _itoa_word (l->l_addr, &buf[sizeof buf - 1], 16, 0); while ((size_t) (&buf[sizeof buf - 1] - bp) < sizeof l->l_addr * 2) *--bp = '0'; _dl_sysdep_message ("\t", l->l_libname->name, " => ", l->l_name, " (0x", bp, ")\n", NULL); } } if (mode != trace) for (i = 1; i < _dl_argc; ++i) { const ElfW(Sym) *ref = NULL; ElfW(Addr) loadbase = _dl_lookup_symbol (_dl_argv[i], &ref, &_dl_default_scope[2], "argument", ELF_MACHINE_JMP_SLOT); char buf[20], *bp; buf[sizeof buf - 1] = '\0'; bp = _itoa_word (ref->st_value, &buf[sizeof buf - 1], 16, 0); while ((size_t) (&buf[sizeof buf - 1] - bp) < sizeof loadbase * 2) *--bp = '0'; _dl_sysdep_message (_dl_argv[i], " found at 0x", bp, NULL); buf[sizeof buf - 1] = '\0'; bp = _itoa_word (loadbase, &buf[sizeof buf - 1], 16, 0); while ((size_t) (&buf[sizeof buf - 1] - bp) < sizeof loadbase * 2) *--bp = '0'; _dl_sysdep_message (" in object at 0x", bp, "\n", NULL); } else { if (lazy >= 0) { /* We have to do symbol dependency testing. */ struct relocate_args args; struct link_map *l; args.lazy = lazy; l = _dl_loaded; while (l->l_next) l = l->l_next; do { if (l != &_dl_rtld_map && l->l_opencount > 0) { args.l = l; _dl_receive_error (print_unresolved, relocate_doit, &args); *_dl_global_scope_end = NULL; } l = l->l_prev; } while (l); } #define VERNEEDTAG (DT_NUM + DT_PROCNUM + DT_VERSIONTAGIDX (DT_VERNEED)) if (*(getenv ("LD_VERBOSE") ?: "") != '\0') { /* Print more information. This means here, print information about the versions needed. */ int first = 1; struct link_map *map = _dl_loaded; for (map = _dl_loaded; map != NULL; map = map->l_next) { const char *strtab; ElfW(Dyn) *dyn = map->l_info[VERNEEDTAG]; ElfW(Verneed) *ent; if (dyn == NULL) continue; strtab = (const char *) (map->l_addr + map->l_info[DT_STRTAB]->d_un.d_ptr); ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr); if (first) { _dl_sysdep_message ("\n\tVersion information:\n", NULL); first = 0; } _dl_sysdep_message ("\t", (map->l_name[0] ? map->l_name : _dl_argv[0]), ":\n", NULL); while (1) { ElfW(Vernaux) *aux; struct link_map *needed; needed = find_needed (strtab + ent->vn_file); aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux); while (1) { const char *fname = NULL; _dl_sysdep_message ("\t\t", strtab + ent->vn_file, " (", strtab + aux->vna_name, ") ", (aux->vna_flags & VER_FLG_WEAK ? "[WEAK] " : ""), "=> ", NULL); if (needed != NULL && match_version (strtab+aux->vna_name, needed)) fname = needed->l_name; _dl_sysdep_message (fname ?: "not found", "\n", NULL); if (aux->vna_next == 0) /* No more symbols. */ break; /* Next symbol. */ aux = (ElfW(Vernaux) *) ((char *) aux + aux->vna_next); } if (ent->vn_next == 0) /* No more dependencies. */ break; /* Next dependency. */ ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next); } } } } _exit (0); } { /* Now we have all the objects loaded. Relocate them all except for the dynamic linker itself. We do this in reverse order so that copy relocs of earlier objects overwrite the data written by later objects. We do not re-relocate the dynamic linker itself in this loop because that could result in the GOT entries for functions we call being changed, and that would break us. It is safe to relocate the dynamic linker out of order because it has no copy relocs (we know that because it is self-contained). */ struct link_map *l; l = _dl_loaded; while (l->l_next) l = l->l_next; do { if (l != &_dl_rtld_map) { _dl_relocate_object (l, _dl_object_relocation_scope (l), lazy); *_dl_global_scope_end = NULL; } l = l->l_prev; } while (l); /* Do any necessary cleanups for the startup OS interface code. We do these now so that no calls are made after rtld re-relocation which might be resolved to different functions than we expect. We cannot do this before relocating the other objects because _dl_relocate_object might need to call `mprotect' for DT_TEXTREL. */ _dl_sysdep_start_cleanup (); if (_dl_rtld_map.l_opencount > 0) /* There was an explicit ref to the dynamic linker as a shared lib. Re-relocate ourselves with user-controlled symbol definitions. */ _dl_relocate_object (&_dl_rtld_map, &_dl_default_scope[2], 0); } { /* Initialize _r_debug. */ struct r_debug *r = _dl_debug_initialize (_dl_rtld_map.l_addr); struct link_map *l; l = _dl_loaded; #ifdef ELF_MACHINE_DEBUG_SETUP /* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */ ELF_MACHINE_DEBUG_SETUP (l, r); ELF_MACHINE_DEBUG_SETUP (&_dl_rtld_map, r); #else if (l->l_info[DT_DEBUG]) /* There is a DT_DEBUG entry in the dynamic section. Fill it in with the run-time address of the r_debug structure */ l->l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r; /* Fill in the pointer in the dynamic linker's own dynamic section, in case you run gdb on the dynamic linker directly. */ if (_dl_rtld_map.l_info[DT_DEBUG]) _dl_rtld_map.l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r; #endif /* Notify the debugger that all objects are now mapped in. */ r->r_state = RT_ADD; _dl_debug_state (); } /* Now enable profiling if needed. */ if (_dl_profile_map != NULL) /* We must prepare the profiling. */ _dl_start_profile (_dl_profile_map, _dl_profile_output); /* Once we return, _dl_sysdep_start will invoke the DT_INIT functions and then *USER_ENTRY. */ } /* This is a little helper function for resolving symbols while tracing the binary. */ static void print_unresolved (int errcode __attribute__ ((unused)), const char *objname, const char *errstring) { if (objname[0] == '\0') objname = _dl_argv[0] ?: "<main program>"; _dl_sysdep_error (errstring, " (", objname, ")\n", NULL); } /* This is a little helper function for resolving symbols while tracing the binary. */ static void print_missing_version (int errcode __attribute__ ((unused)), const char *objname, const char *errstring) { _dl_sysdep_error (_dl_argv[0] ?: "<program name unknown>", ": ", objname, ": ", errstring, "\n", NULL); } /* Process the string given as the parameter which explains which debugging options are enabled. */ static void process_dl_debug (char *dl_debug) { do { #define issep(Ch) ((Ch) == ' ' || (Ch) == ',') /* Skip separating white spaces and commas. */ while (issep (*dl_debug)) ++dl_debug; if (*dl_debug != '\0') { if (strncmp (dl_debug, "libs", 4) == 0 && (issep (dl_debug[4]) || dl_debug[4] == '\0')) { _dl_debug_libs = 1; dl_debug += 4; } else if (strncmp (dl_debug, "help", 4) == 0 && (issep (dl_debug[4]) || dl_debug[4] == '\0')) { _dl_sysdep_message ("\ Valid options for the LD_DEBUG environment variable are:\n\ \n\ help display this help message and exit libs display library search paths\n", NULL); _exit (0); } else /* Skip everything until next separator. */ do ++dl_debug; while (*dl_debug != '\0' && !issep (*dl_debug)); } } while (*dl_debug != '\0'); } /* Process all environments variables the dynamic linker must recognize. Since all of them start with `LD_' we are a bit smarter while finding all the entries. */ static void process_envvars (enum mode *modep, int *lazyp) { char **runp = NULL; char *envline; enum mode mode = normal; int bind_now = 0; /* This is the default place for profiling data file. */ _dl_profile_output = "/var/tmp"; while ((envline = _dl_next_ld_env_entry (&runp)) != NULL) { int result; /* Do we bind early? */ result = strncmp (&envline[3], "BIND_NOW=", 9); if (result == 0) { bind_now = 1; continue; } if (result < 0) continue; /* Debugging of the dynamic linker? */ result = strncmp (&envline[3], "DEBUG=", 6); if (result == 0) { process_dl_debug (&envline[9]); continue; } if (result < 0) continue; /* Which shared object shall be profiled. */ result = strncmp (&envline[3], "PROFILE=", 8); if (result == 0) { _dl_profile = &envline[11]; if (*_dl_profile == '\0') _dl_profile = NULL; continue; } if (result < 0) continue; /* Where to place the profiling data file. */ result = strncmp (&envline[3], "PROFILE_OUTPUT=", 15); if (result == 0) { _dl_profile_output = &envline[18]; if (*_dl_profile_output == '\0') _dl_profile_output = "/var/tmp"; continue; } if (result < 0) continue; /* Test whether we want to see the content of the auxiliary array passed up from the kernel. */ result = strncmp (&envline[3], "SHOW_AUXV=", 10); if (result == 0) { _dl_show_auxv (); continue; } if (result < 0) continue; /* The mode of the dynamic linker can be set. */ result = strncmp (&envline[3], "TRACE_LOADED_OBJECTS=", 21); if (result == 0) { mode = trace; continue; } if (result < 0) continue; /* Warning level, verbose or not. */ result = strncmp (&envline[3], "WARN=", 5); if (result == 0) { _dl_verbose = envline[8] != '\0'; continue; } } /* LAZY is determined by the environment variable LD_WARN and LD_BIND_NOW if we trace the binary. */ if (mode == trace) *lazyp = _dl_verbose ? !bind_now : -1; else *lazyp = !__libc_enable_secure && !bind_now; *modep = mode; }


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