diff options
Diffstat (limited to 'tools/testing/selftests/proc/proc-empty-vm.c')
| -rw-r--r-- | tools/testing/selftests/proc/proc-empty-vm.c | 544 |
1 files changed, 544 insertions, 0 deletions
diff --git a/tools/testing/selftests/proc/proc-empty-vm.c b/tools/testing/selftests/proc/proc-empty-vm.c new file mode 100644 index 000000000000..56198d4ca2bf --- /dev/null +++ b/tools/testing/selftests/proc/proc-empty-vm.c @@ -0,0 +1,544 @@ +#if defined __amd64__ || defined __i386__ +/* + * Copyright (c) 2022 Alexey Dobriyan <adobriyan@gmail.com> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ +/* + * Create a process without mappings by unmapping everything at once and + * holding it with ptrace(2). See what happens to + * + * /proc/${pid}/maps + * /proc/${pid}/numa_maps + * /proc/${pid}/smaps + * /proc/${pid}/smaps_rollup + */ +#undef _GNU_SOURCE +#define _GNU_SOURCE + +#undef NDEBUG +#include <assert.h> +#include <errno.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <fcntl.h> +#include <sys/mman.h> +#include <sys/ptrace.h> +#include <sys/resource.h> +#include <sys/syscall.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <unistd.h> + +#ifdef __amd64__ +#define TEST_VSYSCALL +#endif + +#if defined __amd64__ + #ifndef SYS_pkey_alloc + #define SYS_pkey_alloc 330 + #endif + #ifndef SYS_pkey_free + #define SYS_pkey_free 331 + #endif +#elif defined __i386__ + #ifndef SYS_pkey_alloc + #define SYS_pkey_alloc 381 + #endif + #ifndef SYS_pkey_free + #define SYS_pkey_free 382 + #endif +#else + #error "SYS_pkey_alloc" +#endif + +static int g_protection_key_support; + +static int protection_key_support(void) +{ + long rv = syscall(SYS_pkey_alloc, 0, 0); + if (rv > 0) { + syscall(SYS_pkey_free, (int)rv); + return 1; + } else if (rv == -1 && errno == ENOSYS) { + return 0; + } else if (rv == -1 && errno == EINVAL) { + // ospke=n + return 0; + } else { + fprintf(stderr, "%s: error: rv %ld, errno %d\n", __func__, rv, errno); + exit(EXIT_FAILURE); + } +} + +/* + * 0: vsyscall VMA doesn't exist vsyscall=none + * 1: vsyscall VMA is --xp vsyscall=xonly + * 2: vsyscall VMA is r-xp vsyscall=emulate + */ +static volatile int g_vsyscall; +static const char *g_proc_pid_maps_vsyscall; +static const char *g_proc_pid_smaps_vsyscall; + +static const char proc_pid_maps_vsyscall_0[] = ""; +static const char proc_pid_maps_vsyscall_1[] = +"ffffffffff600000-ffffffffff601000 --xp 00000000 00:00 0 [vsyscall]\n"; +static const char proc_pid_maps_vsyscall_2[] = +"ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]\n"; + +static const char proc_pid_smaps_vsyscall_0[] = ""; + +static const char proc_pid_smaps_vsyscall_1[] = +"ffffffffff600000-ffffffffff601000 --xp 00000000 00:00 0 [vsyscall]\n" +"Size: 4 kB\n" +"KernelPageSize: 4 kB\n" +"MMUPageSize: 4 kB\n" +"Rss: 0 kB\n" +"Pss: 0 kB\n" +"Pss_Dirty: 0 kB\n" +"Shared_Clean: 0 kB\n" +"Shared_Dirty: 0 kB\n" +"Private_Clean: 0 kB\n" +"Private_Dirty: 0 kB\n" +"Referenced: 0 kB\n" +"Anonymous: 0 kB\n" +"KSM: 0 kB\n" +"LazyFree: 0 kB\n" +"AnonHugePages: 0 kB\n" +"ShmemPmdMapped: 0 kB\n" +"FilePmdMapped: 0 kB\n" +"Shared_Hugetlb: 0 kB\n" +"Private_Hugetlb: 0 kB\n" +"Swap: 0 kB\n" +"SwapPss: 0 kB\n" +"Locked: 0 kB\n" +"THPeligible: 0\n" +; + +static const char proc_pid_smaps_vsyscall_2[] = +"ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]\n" +"Size: 4 kB\n" +"KernelPageSize: 4 kB\n" +"MMUPageSize: 4 kB\n" +"Rss: 0 kB\n" +"Pss: 0 kB\n" +"Pss_Dirty: 0 kB\n" +"Shared_Clean: 0 kB\n" +"Shared_Dirty: 0 kB\n" +"Private_Clean: 0 kB\n" +"Private_Dirty: 0 kB\n" +"Referenced: 0 kB\n" +"Anonymous: 0 kB\n" +"KSM: 0 kB\n" +"LazyFree: 0 kB\n" +"AnonHugePages: 0 kB\n" +"ShmemPmdMapped: 0 kB\n" +"FilePmdMapped: 0 kB\n" +"Shared_Hugetlb: 0 kB\n" +"Private_Hugetlb: 0 kB\n" +"Swap: 0 kB\n" +"SwapPss: 0 kB\n" +"Locked: 0 kB\n" +"THPeligible: 0\n" +; + +static void sigaction_SIGSEGV(int _, siginfo_t *__, void *___) +{ + _exit(EXIT_FAILURE); +} + +#ifdef TEST_VSYSCALL +static void sigaction_SIGSEGV_vsyscall(int _, siginfo_t *__, void *___) +{ + _exit(g_vsyscall); +} + +/* + * vsyscall page can't be unmapped, probe it directly. + */ +static void vsyscall(void) +{ + pid_t pid; + int wstatus; + + pid = fork(); + if (pid < 0) { + fprintf(stderr, "fork, errno %d\n", errno); + exit(1); + } + if (pid == 0) { + setrlimit(RLIMIT_CORE, &(struct rlimit){}); + + /* Hide "segfault at ffffffffff600000" messages. */ + struct sigaction act = {}; + act.sa_flags = SA_SIGINFO; + act.sa_sigaction = sigaction_SIGSEGV_vsyscall; + sigaction(SIGSEGV, &act, NULL); + + g_vsyscall = 0; + /* gettimeofday(NULL, NULL); */ + uint64_t rax = 0xffffffffff600000; + asm volatile ( + "call *%[rax]" + : [rax] "+a" (rax) + : "D" (NULL), "S" (NULL) + : "rcx", "r11" + ); + + g_vsyscall = 1; + *(volatile int *)0xffffffffff600000UL; + + g_vsyscall = 2; + exit(g_vsyscall); + } + waitpid(pid, &wstatus, 0); + if (WIFEXITED(wstatus)) { + g_vsyscall = WEXITSTATUS(wstatus); + } else { + fprintf(stderr, "error: vsyscall wstatus %08x\n", wstatus); + exit(1); + } +} +#endif + +static int test_proc_pid_maps(pid_t pid) +{ + char buf[4096]; + snprintf(buf, sizeof(buf), "/proc/%u/maps", pid); + int fd = open(buf, O_RDONLY); + if (fd == -1) { + perror("open /proc/${pid}/maps"); + return EXIT_FAILURE; + } else { + ssize_t rv = read(fd, buf, sizeof(buf)); + close(fd); + if (g_vsyscall == 0) { + assert(rv == 0); + } else { + size_t len = strlen(g_proc_pid_maps_vsyscall); + assert(rv == len); + assert(memcmp(buf, g_proc_pid_maps_vsyscall, len) == 0); + } + return EXIT_SUCCESS; + } +} + +static int test_proc_pid_numa_maps(pid_t pid) +{ + char buf[4096]; + snprintf(buf, sizeof(buf), "/proc/%u/numa_maps", pid); + int fd = open(buf, O_RDONLY); + if (fd == -1) { + if (errno == ENOENT) { + /* + * /proc/${pid}/numa_maps is under CONFIG_NUMA, + * it doesn't necessarily exist. + */ + return EXIT_SUCCESS; + } + perror("open /proc/${pid}/numa_maps"); + return EXIT_FAILURE; + } else { + ssize_t rv = read(fd, buf, sizeof(buf)); + close(fd); + assert(rv == 0); + return EXIT_SUCCESS; + } +} + +static int test_proc_pid_smaps(pid_t pid) +{ + char buf[4096]; + snprintf(buf, sizeof(buf), "/proc/%u/smaps", pid); + int fd = open(buf, O_RDONLY); + if (fd == -1) { + if (errno == ENOENT) { + /* + * /proc/${pid}/smaps is under CONFIG_PROC_PAGE_MONITOR, + * it doesn't necessarily exist. + */ + return EXIT_SUCCESS; + } + perror("open /proc/${pid}/smaps"); + return EXIT_FAILURE; + } + ssize_t rv = read(fd, buf, sizeof(buf)); + close(fd); + + assert(0 <= rv); + assert(rv <= sizeof(buf)); + + if (g_vsyscall == 0) { + assert(rv == 0); + } else { + size_t len = strlen(g_proc_pid_smaps_vsyscall); + assert(rv > len); + assert(memcmp(buf, g_proc_pid_smaps_vsyscall, len) == 0); + + if (g_protection_key_support) { +#define PROTECTION_KEY "ProtectionKey: 0\n" + assert(memmem(buf, rv, PROTECTION_KEY, strlen(PROTECTION_KEY))); + } + } + + return EXIT_SUCCESS; +} + +static const char g_smaps_rollup[] = +"00000000-00000000 ---p 00000000 00:00 0 [rollup]\n" +"Rss: 0 kB\n" +"Pss: 0 kB\n" +"Pss_Dirty: 0 kB\n" +"Pss_Anon: 0 kB\n" +"Pss_File: 0 kB\n" +"Pss_Shmem: 0 kB\n" +"Shared_Clean: 0 kB\n" +"Shared_Dirty: 0 kB\n" +"Private_Clean: 0 kB\n" +"Private_Dirty: 0 kB\n" +"Referenced: 0 kB\n" +"Anonymous: 0 kB\n" +"KSM: 0 kB\n" +"LazyFree: 0 kB\n" +"AnonHugePages: 0 kB\n" +"ShmemPmdMapped: 0 kB\n" +"FilePmdMapped: 0 kB\n" +"Shared_Hugetlb: 0 kB\n" +"Private_Hugetlb: 0 kB\n" +"Swap: 0 kB\n" +"SwapPss: 0 kB\n" +"Locked: 0 kB\n" +; + +static int test_proc_pid_smaps_rollup(pid_t pid) +{ + char buf[4096]; + snprintf(buf, sizeof(buf), "/proc/%u/smaps_rollup", pid); + int fd = open(buf, O_RDONLY); + if (fd == -1) { + if (errno == ENOENT) { + /* + * /proc/${pid}/smaps_rollup is under CONFIG_PROC_PAGE_MONITOR, + * it doesn't necessarily exist. + */ + return EXIT_SUCCESS; + } + perror("open /proc/${pid}/smaps_rollup"); + return EXIT_FAILURE; + } else { + ssize_t rv = read(fd, buf, sizeof(buf)); + close(fd); + assert(rv == sizeof(g_smaps_rollup) - 1); + assert(memcmp(buf, g_smaps_rollup, sizeof(g_smaps_rollup) - 1) == 0); + return EXIT_SUCCESS; + } +} + +static const char *parse_u64(const char *p, const char *const end, uint64_t *rv) +{ + *rv = 0; + for (; p != end; p += 1) { + if ('0' <= *p && *p <= '9') { + assert(!__builtin_mul_overflow(*rv, 10, rv)); + assert(!__builtin_add_overflow(*rv, *p - '0', rv)); + } else { + break; + } + } + assert(p != end); + return p; +} + +/* + * There seems to be 2 types of valid output: + * "0 A A B 0 0 0\n" for dynamic exeuctables, + * "0 0 0 B 0 0 0\n" for static executables. + */ +static int test_proc_pid_statm(pid_t pid) +{ + char buf[4096]; + snprintf(buf, sizeof(buf), "/proc/%u/statm", pid); + int fd = open(buf, O_RDONLY); + if (fd == -1) { + perror("open /proc/${pid}/statm"); + return EXIT_FAILURE; + } + + ssize_t rv = read(fd, buf, sizeof(buf)); + close(fd); + + assert(rv >= 0); + assert(rv <= sizeof(buf)); + if (0) { + write(1, buf, rv); + } + + const char *p = buf; + const char *const end = p + rv; + + /* size */ + assert(p != end && *p++ == '0'); + assert(p != end && *p++ == ' '); + + uint64_t resident; + p = parse_u64(p, end, &resident); + assert(p != end && *p++ == ' '); + + uint64_t shared; + p = parse_u64(p, end, &shared); + assert(p != end && *p++ == ' '); + + uint64_t text; + p = parse_u64(p, end, &text); + assert(p != end && *p++ == ' '); + + assert(p != end && *p++ == '0'); + assert(p != end && *p++ == ' '); + + /* data */ + assert(p != end && *p++ == '0'); + assert(p != end && *p++ == ' '); + + assert(p != end && *p++ == '0'); + assert(p != end && *p++ == '\n'); + + assert(p == end); + + /* + * "text" is "mm->end_code - mm->start_code" at execve(2) time. + * munmap() doesn't change it. It can be anything (just link + * statically). It can't be 0 because executing to this point + * implies at least 1 page of code. + */ + assert(text > 0); + + /* + * These two are always equal. Always 0 for statically linked + * executables and sometimes 0 for dynamically linked executables. + * There is no way to tell one from another without parsing ELF + * which is too much for this test. + */ + assert(resident == shared); + + return EXIT_SUCCESS; +} + +int main(void) +{ + int rv = EXIT_SUCCESS; + +#ifdef TEST_VSYSCALL + vsyscall(); +#endif + + switch (g_vsyscall) { + case 0: + g_proc_pid_maps_vsyscall = proc_pid_maps_vsyscall_0; + g_proc_pid_smaps_vsyscall = proc_pid_smaps_vsyscall_0; + break; + case 1: + g_proc_pid_maps_vsyscall = proc_pid_maps_vsyscall_1; + g_proc_pid_smaps_vsyscall = proc_pid_smaps_vsyscall_1; + break; + case 2: + g_proc_pid_maps_vsyscall = proc_pid_maps_vsyscall_2; + g_proc_pid_smaps_vsyscall = proc_pid_smaps_vsyscall_2; + break; + default: + abort(); + } + + g_protection_key_support = protection_key_support(); + + pid_t pid = fork(); + if (pid == -1) { + perror("fork"); + return EXIT_FAILURE; + } else if (pid == 0) { + rv = ptrace(PTRACE_TRACEME, 0, NULL, NULL); + if (rv != 0) { + if (errno == EPERM) { + fprintf(stderr, +"Did you know? ptrace(PTRACE_TRACEME) doesn't work under strace.\n" + ); + kill(getppid(), SIGTERM); + return EXIT_FAILURE; + } + perror("ptrace PTRACE_TRACEME"); + return EXIT_FAILURE; + } + + /* + * Hide "segfault at ..." messages. Signal handler won't run. + */ + struct sigaction act = {}; + act.sa_flags = SA_SIGINFO; + act.sa_sigaction = sigaction_SIGSEGV; + sigaction(SIGSEGV, &act, NULL); + +#ifdef __amd64__ + munmap(NULL, ((size_t)1 << 47) - 4096); +#elif defined __i386__ + { + size_t len; + + for (len = -4096;; len -= 4096) { + munmap(NULL, len); + } + } +#else +#error "implement 'unmap everything'" +#endif + return EXIT_FAILURE; + } else { + /* + * TODO find reliable way to signal parent that munmap(2) completed. + * Child can't do it directly because it effectively doesn't exist + * anymore. Looking at child's VM files isn't 100% reliable either: + * due to a bug they may not become empty or empty-like. + */ + sleep(1); + + if (rv == EXIT_SUCCESS) { + rv = test_proc_pid_maps(pid); + } + if (rv == EXIT_SUCCESS) { + rv = test_proc_pid_numa_maps(pid); + } + if (rv == EXIT_SUCCESS) { + rv = test_proc_pid_smaps(pid); + } + if (rv == EXIT_SUCCESS) { + rv = test_proc_pid_smaps_rollup(pid); + } + if (rv == EXIT_SUCCESS) { + rv = test_proc_pid_statm(pid); + } + + /* Cut the rope. */ + int wstatus; + waitpid(pid, &wstatus, 0); + assert(WIFSTOPPED(wstatus)); + assert(WSTOPSIG(wstatus) == SIGSEGV); + } + + return rv; +} +#else +int main(void) +{ + return 4; +} +#endif |