| //===-- sanitizer_linux.cc ------------------------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file is shared between AddressSanitizer and ThreadSanitizer |
| // run-time libraries and implements linux-specific functions from |
| // sanitizer_libc.h. |
| //===----------------------------------------------------------------------===// |
| |
| #include "sanitizer_platform.h" |
| #if SANITIZER_LINUX |
| |
| #include "sanitizer_common.h" |
| #include "sanitizer_internal_defs.h" |
| #include "sanitizer_libc.h" |
| #include "sanitizer_linux.h" |
| #include "sanitizer_mutex.h" |
| #include "sanitizer_placement_new.h" |
| #include "sanitizer_procmaps.h" |
| #include "sanitizer_stacktrace.h" |
| #include "sanitizer_symbolizer.h" |
| |
| #include <asm/param.h> |
| #include <dlfcn.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <pthread.h> |
| #include <sched.h> |
| #include <sys/mman.h> |
| #include <sys/ptrace.h> |
| #include <sys/resource.h> |
| #include <sys/stat.h> |
| #include <sys/syscall.h> |
| #include <sys/time.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| #include <unwind.h> |
| |
| #if !SANITIZER_ANDROID |
| #include <sys/signal.h> |
| #endif |
| |
| // <linux/time.h> |
| struct kernel_timeval { |
| long tv_sec; |
| long tv_usec; |
| }; |
| |
| // <linux/futex.h> is broken on some linux distributions. |
| const int FUTEX_WAIT = 0; |
| const int FUTEX_WAKE = 1; |
| |
| // Are we using 32-bit or 64-bit syscalls? |
| // x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 32 |
| // but it still needs to use 64-bit syscalls. |
| #if defined(__x86_64__) || SANITIZER_WORDSIZE == 64 |
| # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 1 |
| #else |
| # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 0 |
| #endif |
| |
| namespace __sanitizer { |
| |
| #ifdef __x86_64__ |
| #include "sanitizer_syscall_linux_x86_64.inc" |
| #else |
| #include "sanitizer_syscall_generic.inc" |
| #endif |
| |
| // --------------- sanitizer_libc.h |
| uptr internal_mmap(void *addr, uptr length, int prot, int flags, |
| int fd, u64 offset) { |
| #if SANITIZER_LINUX_USES_64BIT_SYSCALLS |
| return internal_syscall(__NR_mmap, addr, length, prot, flags, fd, offset); |
| #else |
| return internal_syscall(__NR_mmap2, addr, length, prot, flags, fd, offset); |
| #endif |
| } |
| |
| uptr internal_munmap(void *addr, uptr length) { |
| return internal_syscall(__NR_munmap, addr, length); |
| } |
| |
| uptr internal_close(fd_t fd) { |
| return internal_syscall(__NR_close, fd); |
| } |
| |
| uptr internal_open(const char *filename, int flags) { |
| return internal_syscall(__NR_open, filename, flags); |
| } |
| |
| uptr internal_open(const char *filename, int flags, u32 mode) { |
| return internal_syscall(__NR_open, filename, flags, mode); |
| } |
| |
| uptr OpenFile(const char *filename, bool write) { |
| return internal_open(filename, |
| write ? O_WRONLY | O_CREAT /*| O_CLOEXEC*/ : O_RDONLY, 0660); |
| } |
| |
| uptr internal_read(fd_t fd, void *buf, uptr count) { |
| sptr res; |
| HANDLE_EINTR(res, (sptr)internal_syscall(__NR_read, fd, buf, count)); |
| return res; |
| } |
| |
| uptr internal_write(fd_t fd, const void *buf, uptr count) { |
| sptr res; |
| HANDLE_EINTR(res, (sptr)internal_syscall(__NR_write, fd, buf, count)); |
| return res; |
| } |
| |
| #if !SANITIZER_LINUX_USES_64BIT_SYSCALLS |
| static void stat64_to_stat(struct stat64 *in, struct stat *out) { |
| internal_memset(out, 0, sizeof(*out)); |
| out->st_dev = in->st_dev; |
| out->st_ino = in->st_ino; |
| out->st_mode = in->st_mode; |
| out->st_nlink = in->st_nlink; |
| out->st_uid = in->st_uid; |
| out->st_gid = in->st_gid; |
| out->st_rdev = in->st_rdev; |
| out->st_size = in->st_size; |
| out->st_blksize = in->st_blksize; |
| out->st_blocks = in->st_blocks; |
| out->st_atime = in->st_atime; |
| out->st_mtime = in->st_mtime; |
| out->st_ctime = in->st_ctime; |
| out->st_ino = in->st_ino; |
| } |
| #endif |
| |
| uptr internal_stat(const char *path, void *buf) { |
| #if SANITIZER_LINUX_USES_64BIT_SYSCALLS |
| return internal_syscall(__NR_stat, path, buf); |
| #else |
| struct stat64 buf64; |
| int res = internal_syscall(__NR_stat64, path, &buf64); |
| stat64_to_stat(&buf64, (struct stat *)buf); |
| return res; |
| #endif |
| } |
| |
| uptr internal_lstat(const char *path, void *buf) { |
| #if SANITIZER_LINUX_USES_64BIT_SYSCALLS |
| return internal_syscall(__NR_lstat, path, buf); |
| #else |
| struct stat64 buf64; |
| int res = internal_syscall(__NR_lstat64, path, &buf64); |
| stat64_to_stat(&buf64, (struct stat *)buf); |
| return res; |
| #endif |
| } |
| |
| uptr internal_fstat(fd_t fd, void *buf) { |
| #if SANITIZER_LINUX_USES_64BIT_SYSCALLS |
| return internal_syscall(__NR_fstat, fd, buf); |
| #else |
| struct stat64 buf64; |
| int res = internal_syscall(__NR_fstat64, fd, &buf64); |
| stat64_to_stat(&buf64, (struct stat *)buf); |
| return res; |
| #endif |
| } |
| |
| uptr internal_filesize(fd_t fd) { |
| struct stat st; |
| if (internal_fstat(fd, &st)) |
| return -1; |
| return (uptr)st.st_size; |
| } |
| |
| uptr internal_dup2(int oldfd, int newfd) { |
| return internal_syscall(__NR_dup2, oldfd, newfd); |
| } |
| |
| uptr internal_readlink(const char *path, char *buf, uptr bufsize) { |
| return internal_syscall(__NR_readlink, path, buf, bufsize); |
| } |
| |
| uptr internal_unlink(const char *path) { |
| return internal_syscall(__NR_unlink, path); |
| } |
| |
| uptr internal_sched_yield() { |
| return internal_syscall(__NR_sched_yield); |
| } |
| |
| void internal__exit(int exitcode) { |
| internal_syscall(__NR_exit_group, exitcode); |
| Die(); // Unreachable. |
| } |
| |
| uptr internal_execve(const char *filename, char *const argv[], |
| char *const envp[]) { |
| return internal_syscall(__NR_execve, filename, argv, envp); |
| } |
| |
| // ----------------- sanitizer_common.h |
| bool FileExists(const char *filename) { |
| struct stat st; |
| if (internal_stat(filename, &st)) |
| return false; |
| // Sanity check: filename is a regular file. |
| return S_ISREG(st.st_mode); |
| } |
| |
| uptr GetTid() { |
| return internal_syscall(__NR_gettid); |
| } |
| |
| u64 NanoTime() { |
| kernel_timeval tv; |
| internal_syscall(__NR_gettimeofday, &tv, 0); |
| return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000; |
| } |
| |
| // Like getenv, but reads env directly from /proc and does not use libc. |
| // This function should be called first inside __asan_init. |
| const char *GetEnv(const char *name) { |
| static char *environ; |
| static uptr len; |
| static bool inited; |
| if (!inited) { |
| inited = true; |
| uptr environ_size; |
| len = ReadFileToBuffer("/proc/self/environ", |
| &environ, &environ_size, 1 << 26); |
| } |
| if (!environ || len == 0) return 0; |
| uptr namelen = internal_strlen(name); |
| const char *p = environ; |
| while (*p != '\0') { // will happen at the \0\0 that terminates the buffer |
| // proc file has the format NAME=value\0NAME=value\0NAME=value\0... |
| const char* endp = |
| (char*)internal_memchr(p, '\0', len - (p - environ)); |
| if (endp == 0) // this entry isn't NUL terminated |
| return 0; |
| else if (!internal_memcmp(p, name, namelen) && p[namelen] == '=') // Match. |
| return p + namelen + 1; // point after = |
| p = endp + 1; |
| } |
| return 0; // Not found. |
| } |
| |
| extern "C" { |
| extern void *__libc_stack_end SANITIZER_WEAK_ATTRIBUTE; |
| } |
| |
| #if !SANITIZER_GO |
| static void ReadNullSepFileToArray(const char *path, char ***arr, |
| int arr_size) { |
| char *buff; |
| uptr buff_size = 0; |
| *arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray"); |
| ReadFileToBuffer(path, &buff, &buff_size, 1024 * 1024); |
| (*arr)[0] = buff; |
| int count, i; |
| for (count = 1, i = 1; ; i++) { |
| if (buff[i] == 0) { |
| if (buff[i+1] == 0) break; |
| (*arr)[count] = &buff[i+1]; |
| CHECK_LE(count, arr_size - 1); // FIXME: make this more flexible. |
| count++; |
| } |
| } |
| (*arr)[count] = 0; |
| } |
| #endif |
| |
| static void GetArgsAndEnv(char*** argv, char*** envp) { |
| #if !SANITIZER_GO |
| if (&__libc_stack_end) { |
| #endif |
| uptr* stack_end = (uptr*)__libc_stack_end; |
| int argc = *stack_end; |
| *argv = (char**)(stack_end + 1); |
| *envp = (char**)(stack_end + argc + 2); |
| #if !SANITIZER_GO |
| } else { |
| static const int kMaxArgv = 2000, kMaxEnvp = 2000; |
| ReadNullSepFileToArray("/proc/self/cmdline", argv, kMaxArgv); |
| ReadNullSepFileToArray("/proc/self/environ", envp, kMaxEnvp); |
| } |
| #endif |
| } |
| |
| void ReExec() { |
| char **argv, **envp; |
| GetArgsAndEnv(&argv, &envp); |
| uptr rv = internal_execve("/proc/self/exe", argv, envp); |
| int rverrno; |
| CHECK_EQ(internal_iserror(rv, &rverrno), true); |
| Printf("execve failed, errno %d\n", rverrno); |
| Die(); |
| } |
| |
| void PrepareForSandboxing() { |
| // Some kinds of sandboxes may forbid filesystem access, so we won't be able |
| // to read the file mappings from /proc/self/maps. Luckily, neither the |
| // process will be able to load additional libraries, so it's fine to use the |
| // cached mappings. |
| MemoryMappingLayout::CacheMemoryMappings(); |
| // Same for /proc/self/exe in the symbolizer. |
| SymbolizerPrepareForSandboxing(); |
| } |
| |
| // ----------------- sanitizer_procmaps.h |
| // Linker initialized. |
| ProcSelfMapsBuff MemoryMappingLayout::cached_proc_self_maps_; |
| StaticSpinMutex MemoryMappingLayout::cache_lock_; // Linker initialized. |
| |
| MemoryMappingLayout::MemoryMappingLayout(bool cache_enabled) { |
| proc_self_maps_.len = |
| ReadFileToBuffer("/proc/self/maps", &proc_self_maps_.data, |
| &proc_self_maps_.mmaped_size, 1 << 26); |
| if (cache_enabled) { |
| if (proc_self_maps_.mmaped_size == 0) { |
| LoadFromCache(); |
| CHECK_GT(proc_self_maps_.len, 0); |
| } |
| } else { |
| CHECK_GT(proc_self_maps_.mmaped_size, 0); |
| } |
| Reset(); |
| // FIXME: in the future we may want to cache the mappings on demand only. |
| if (cache_enabled) |
| CacheMemoryMappings(); |
| } |
| |
| MemoryMappingLayout::~MemoryMappingLayout() { |
| // Only unmap the buffer if it is different from the cached one. Otherwise |
| // it will be unmapped when the cache is refreshed. |
| if (proc_self_maps_.data != cached_proc_self_maps_.data) { |
| UnmapOrDie(proc_self_maps_.data, proc_self_maps_.mmaped_size); |
| } |
| } |
| |
| void MemoryMappingLayout::Reset() { |
| current_ = proc_self_maps_.data; |
| } |
| |
| // static |
| void MemoryMappingLayout::CacheMemoryMappings() { |
| SpinMutexLock l(&cache_lock_); |
| // Don't invalidate the cache if the mappings are unavailable. |
| ProcSelfMapsBuff old_proc_self_maps; |
| old_proc_self_maps = cached_proc_self_maps_; |
| cached_proc_self_maps_.len = |
| ReadFileToBuffer("/proc/self/maps", &cached_proc_self_maps_.data, |
| &cached_proc_self_maps_.mmaped_size, 1 << 26); |
| if (cached_proc_self_maps_.mmaped_size == 0) { |
| cached_proc_self_maps_ = old_proc_self_maps; |
| } else { |
| if (old_proc_self_maps.mmaped_size) { |
| UnmapOrDie(old_proc_self_maps.data, |
| old_proc_self_maps.mmaped_size); |
| } |
| } |
| } |
| |
| void MemoryMappingLayout::LoadFromCache() { |
| SpinMutexLock l(&cache_lock_); |
| if (cached_proc_self_maps_.data) { |
| proc_self_maps_ = cached_proc_self_maps_; |
| } |
| } |
| |
| // Parse a hex value in str and update str. |
| static uptr ParseHex(char **str) { |
| uptr x = 0; |
| char *s; |
| for (s = *str; ; s++) { |
| char c = *s; |
| uptr v = 0; |
| if (c >= '0' && c <= '9') |
| v = c - '0'; |
| else if (c >= 'a' && c <= 'f') |
| v = c - 'a' + 10; |
| else if (c >= 'A' && c <= 'F') |
| v = c - 'A' + 10; |
| else |
| break; |
| x = x * 16 + v; |
| } |
| *str = s; |
| return x; |
| } |
| |
| static bool IsOneOf(char c, char c1, char c2) { |
| return c == c1 || c == c2; |
| } |
| |
| static bool IsDecimal(char c) { |
| return c >= '0' && c <= '9'; |
| } |
| |
| bool MemoryMappingLayout::Next(uptr *start, uptr *end, uptr *offset, |
| char filename[], uptr filename_size, |
| uptr *protection) { |
| char *last = proc_self_maps_.data + proc_self_maps_.len; |
| if (current_ >= last) return false; |
| uptr dummy; |
| if (!start) start = &dummy; |
| if (!end) end = &dummy; |
| if (!offset) offset = &dummy; |
| char *next_line = (char*)internal_memchr(current_, '\n', last - current_); |
| if (next_line == 0) |
| next_line = last; |
| // Example: 08048000-08056000 r-xp 00000000 03:0c 64593 /foo/bar |
| *start = ParseHex(¤t_); |
| CHECK_EQ(*current_++, '-'); |
| *end = ParseHex(¤t_); |
| CHECK_EQ(*current_++, ' '); |
| uptr local_protection = 0; |
| CHECK(IsOneOf(*current_, '-', 'r')); |
| if (*current_++ == 'r') |
| local_protection |= kProtectionRead; |
| CHECK(IsOneOf(*current_, '-', 'w')); |
| if (*current_++ == 'w') |
| local_protection |= kProtectionWrite; |
| CHECK(IsOneOf(*current_, '-', 'x')); |
| if (*current_++ == 'x') |
| local_protection |= kProtectionExecute; |
| CHECK(IsOneOf(*current_, 's', 'p')); |
| if (*current_++ == 's') |
| local_protection |= kProtectionShared; |
| if (protection) { |
| *protection = local_protection; |
| } |
| CHECK_EQ(*current_++, ' '); |
| *offset = ParseHex(¤t_); |
| CHECK_EQ(*current_++, ' '); |
| ParseHex(¤t_); |
| CHECK_EQ(*current_++, ':'); |
| ParseHex(¤t_); |
| CHECK_EQ(*current_++, ' '); |
| while (IsDecimal(*current_)) |
| current_++; |
| // Qemu may lack the trailing space. |
| // http://code.google.com/p/address-sanitizer/issues/detail?id=160 |
| // CHECK_EQ(*current_++, ' '); |
| // Skip spaces. |
| while (current_ < next_line && *current_ == ' ') |
| current_++; |
| // Fill in the filename. |
| uptr i = 0; |
| while (current_ < next_line) { |
| if (filename && i < filename_size - 1) |
| filename[i++] = *current_; |
| current_++; |
| } |
| if (filename && i < filename_size) |
| filename[i] = 0; |
| current_ = next_line + 1; |
| return true; |
| } |
| |
| // Gets the object name and the offset by walking MemoryMappingLayout. |
| bool MemoryMappingLayout::GetObjectNameAndOffset(uptr addr, uptr *offset, |
| char filename[], |
| uptr filename_size, |
| uptr *protection) { |
| return IterateForObjectNameAndOffset(addr, offset, filename, filename_size, |
| protection); |
| } |
| |
| enum MutexState { |
| MtxUnlocked = 0, |
| MtxLocked = 1, |
| MtxSleeping = 2 |
| }; |
| |
| BlockingMutex::BlockingMutex(LinkerInitialized) { |
| CHECK_EQ(owner_, 0); |
| } |
| |
| BlockingMutex::BlockingMutex() { |
| internal_memset(this, 0, sizeof(*this)); |
| } |
| |
| void BlockingMutex::Lock() { |
| atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_); |
| if (atomic_exchange(m, MtxLocked, memory_order_acquire) == MtxUnlocked) |
| return; |
| while (atomic_exchange(m, MtxSleeping, memory_order_acquire) != MtxUnlocked) |
| internal_syscall(__NR_futex, m, FUTEX_WAIT, MtxSleeping, 0, 0, 0); |
| } |
| |
| void BlockingMutex::Unlock() { |
| atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_); |
| u32 v = atomic_exchange(m, MtxUnlocked, memory_order_relaxed); |
| CHECK_NE(v, MtxUnlocked); |
| if (v == MtxSleeping) |
| internal_syscall(__NR_futex, m, FUTEX_WAKE, 1, 0, 0, 0); |
| } |
| |
| void BlockingMutex::CheckLocked() { |
| atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_); |
| CHECK_NE(MtxUnlocked, atomic_load(m, memory_order_relaxed)); |
| } |
| |
| // ----------------- sanitizer_linux.h |
| // The actual size of this structure is specified by d_reclen. |
| // Note that getdents64 uses a different structure format. We only provide the |
| // 32-bit syscall here. |
| struct linux_dirent { |
| unsigned long d_ino; |
| unsigned long d_off; |
| unsigned short d_reclen; |
| char d_name[256]; |
| }; |
| |
| // Syscall wrappers. |
| uptr internal_ptrace(int request, int pid, void *addr, void *data) { |
| return internal_syscall(__NR_ptrace, request, pid, addr, data); |
| } |
| |
| uptr internal_waitpid(int pid, int *status, int options) { |
| return internal_syscall(__NR_wait4, pid, status, options, 0 /* rusage */); |
| } |
| |
| uptr internal_getpid() { |
| return internal_syscall(__NR_getpid); |
| } |
| |
| uptr internal_getppid() { |
| return internal_syscall(__NR_getppid); |
| } |
| |
| uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) { |
| return internal_syscall(__NR_getdents, fd, dirp, count); |
| } |
| |
| uptr internal_lseek(fd_t fd, OFF_T offset, int whence) { |
| return internal_syscall(__NR_lseek, fd, offset, whence); |
| } |
| |
| uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) { |
| return internal_syscall(__NR_prctl, option, arg2, arg3, arg4, arg5); |
| } |
| |
| uptr internal_sigaltstack(const struct sigaltstack *ss, |
| struct sigaltstack *oss) { |
| return internal_syscall(__NR_sigaltstack, ss, oss); |
| } |
| |
| // ThreadLister implementation. |
| ThreadLister::ThreadLister(int pid) |
| : pid_(pid), |
| descriptor_(-1), |
| buffer_(4096), |
| error_(true), |
| entry_((struct linux_dirent *)buffer_.data()), |
| bytes_read_(0) { |
| char task_directory_path[80]; |
| internal_snprintf(task_directory_path, sizeof(task_directory_path), |
| "/proc/%d/task/", pid); |
| uptr openrv = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY); |
| if (internal_iserror(openrv)) { |
| error_ = true; |
| Report("Can't open /proc/%d/task for reading.\n", pid); |
| } else { |
| error_ = false; |
| descriptor_ = openrv; |
| } |
| } |
| |
| int ThreadLister::GetNextTID() { |
| int tid = -1; |
| do { |
| if (error_) |
| return -1; |
| if ((char *)entry_ >= &buffer_[bytes_read_] && !GetDirectoryEntries()) |
| return -1; |
| if (entry_->d_ino != 0 && entry_->d_name[0] >= '0' && |
| entry_->d_name[0] <= '9') { |
| // Found a valid tid. |
| tid = (int)internal_atoll(entry_->d_name); |
| } |
| entry_ = (struct linux_dirent *)(((char *)entry_) + entry_->d_reclen); |
| } while (tid < 0); |
| return tid; |
| } |
| |
| void ThreadLister::Reset() { |
| if (error_ || descriptor_ < 0) |
| return; |
| internal_lseek(descriptor_, 0, SEEK_SET); |
| } |
| |
| ThreadLister::~ThreadLister() { |
| if (descriptor_ >= 0) |
| internal_close(descriptor_); |
| } |
| |
| bool ThreadLister::error() { return error_; } |
| |
| bool ThreadLister::GetDirectoryEntries() { |
| CHECK_GE(descriptor_, 0); |
| CHECK_NE(error_, true); |
| bytes_read_ = internal_getdents(descriptor_, |
| (struct linux_dirent *)buffer_.data(), |
| buffer_.size()); |
| if (internal_iserror(bytes_read_)) { |
| Report("Can't read directory entries from /proc/%d/task.\n", pid_); |
| error_ = true; |
| return false; |
| } else if (bytes_read_ == 0) { |
| return false; |
| } |
| entry_ = (struct linux_dirent *)buffer_.data(); |
| return true; |
| } |
| |
| uptr GetPageSize() { |
| #if defined(__x86_64__) || defined(__i386__) |
| return EXEC_PAGESIZE; |
| #else |
| return sysconf(_SC_PAGESIZE); // EXEC_PAGESIZE may not be trustworthy. |
| #endif |
| } |
| |
| // Match full names of the form /path/to/base_name{-,.}* |
| bool LibraryNameIs(const char *full_name, const char *base_name) { |
| const char *name = full_name; |
| // Strip path. |
| while (*name != '\0') name++; |
| while (name > full_name && *name != '/') name--; |
| if (*name == '/') name++; |
| uptr base_name_length = internal_strlen(base_name); |
| if (internal_strncmp(name, base_name, base_name_length)) return false; |
| return (name[base_name_length] == '-' || name[base_name_length] == '.'); |
| } |
| |
| } // namespace __sanitizer |
| |
| #endif // SANITIZER_LINUX |