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llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc

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//===-- 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>
#if !SANITIZER_ANDROID
#include <link.h>
#endif
#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_memset(&tv, 0, sizeof(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" {
SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end;
}
#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.
#if !SANITIZER_GO
if (Symbolizer *sym = Symbolizer::GetOrNull())
sym->PrepareForSandboxing();
#endif
}
// ----------------- 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';
}
static bool IsHex(char c) {
return (c >= '0' && c <= '9')
|| (c >= 'a' && c <= 'f');
}
static uptr ReadHex(const char *p) {
uptr v = 0;
for (; IsHex(p[0]); p++) {
if (p[0] >= '0' && p[0] <= '9')
v = v * 16 + p[0] - '0';
else
v = v * 16 + p[0] - 'a' + 10;
}
return v;
}
static uptr ReadDecimal(const char *p) {
uptr v = 0;
for (; IsDecimal(p[0]); p++)
v = v * 10 + p[0] - '0';
return v;
}
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(&current_);
CHECK_EQ(*current_++, '-');
*end = ParseHex(&current_);
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(&current_);
CHECK_EQ(*current_++, ' ');
ParseHex(&current_);
CHECK_EQ(*current_++, ':');
ParseHex(&current_);
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);
}
void GetMemoryProfile(fill_profile_f cb, uptr *stats, uptr stats_size) {
char *smaps = 0;
uptr smaps_cap = 0;
uptr smaps_len = ReadFileToBuffer("/proc/self/smaps",
&smaps, &smaps_cap, 64<<20);
uptr start = 0;
bool file = false;
const char *pos = smaps;
while (pos < smaps + smaps_len) {
if (IsHex(pos[0])) {
start = ReadHex(pos);
for (; *pos != '/' && *pos > '\n'; pos++) {}
file = *pos == '/';
} else if (internal_strncmp(pos, "Rss:", 4) == 0) {
for (; *pos < '0' || *pos > '9'; pos++) {}
uptr rss = ReadDecimal(pos) * 1024;
cb(start, rss, file, stats, stats_size);
}
while (*pos++ != '\n') {}
}
UnmapOrDie(smaps, smaps_cap);
}
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);
}
uptr internal_sigaction(int signum, const __sanitizer_kernel_sigaction_t *act,
__sanitizer_kernel_sigaction_t *oldact) {
return internal_syscall(__NR_rt_sigaction, signum, act, oldact,
sizeof(__sanitizer_kernel_sigset_t));
}
uptr internal_sigprocmask(int how, __sanitizer_kernel_sigset_t *set,
__sanitizer_kernel_sigset_t *oldset) {
return internal_syscall(__NR_rt_sigprocmask, (uptr)how, &set->sig[0],
&oldset->sig[0], sizeof(__sanitizer_kernel_sigset_t));
}
void internal_sigfillset(__sanitizer_kernel_sigset_t *set) {
internal_memset(set, 0xff, sizeof(*set));
}
void internal_sigdelset(__sanitizer_kernel_sigset_t *set, int signum) {
signum -= 1;
CHECK_GE(signum, 0);
CHECK_LT(signum, sizeof(*set) * 8);
const uptr idx = signum / (sizeof(set->sig[0]) * 8);
const uptr bit = signum % (sizeof(set->sig[0]) * 8);
set->sig[idx] &= ~(1 << bit);
}
// 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
}
static char proc_self_exe_cache_str[kMaxPathLength];
static uptr proc_self_exe_cache_len = 0;
uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
uptr module_name_len = internal_readlink(
"/proc/self/exe", buf, buf_len);
int readlink_error;
if (internal_iserror(module_name_len, &readlink_error)) {
if (proc_self_exe_cache_len) {
// If available, use the cached module name.
CHECK_LE(proc_self_exe_cache_len, buf_len);
internal_strncpy(buf, proc_self_exe_cache_str, buf_len);
module_name_len = internal_strlen(proc_self_exe_cache_str);
} else {
// We can't read /proc/self/exe for some reason, assume the name of the
// binary is unknown.
Report("WARNING: readlink(\"/proc/self/exe\") failed with errno %d, "
"some stack frames may not be symbolized\n", readlink_error);
module_name_len = internal_snprintf(buf, buf_len, "/proc/self/exe");
}
CHECK_LT(module_name_len, buf_len);
buf[module_name_len] = '\0';
}
return module_name_len;
}
void CacheBinaryName() {
if (!proc_self_exe_cache_len) {
proc_self_exe_cache_len =
ReadBinaryName(proc_self_exe_cache_str, kMaxPathLength);
}
}
// 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] == '.');
}
#if !SANITIZER_ANDROID
// Call cb for each region mapped by map.
void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) {
typedef ElfW(Phdr) Elf_Phdr;
typedef ElfW(Ehdr) Elf_Ehdr;
char *base = (char *)map->l_addr;
Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
char *phdrs = base + ehdr->e_phoff;
char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize;
// Find the segment with the minimum base so we can "relocate" the p_vaddr
// fields. Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC
// objects have a non-zero base.
uptr preferred_base = (uptr)-1;
for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
Elf_Phdr *phdr = (Elf_Phdr *)iter;
if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr)
preferred_base = (uptr)phdr->p_vaddr;
}
// Compute the delta from the real base to get a relocation delta.
sptr delta = (uptr)base - preferred_base;
// Now we can figure out what the loader really mapped.
for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
Elf_Phdr *phdr = (Elf_Phdr *)iter;
if (phdr->p_type == PT_LOAD) {
uptr seg_start = phdr->p_vaddr + delta;
uptr seg_end = seg_start + phdr->p_memsz;
// None of these values are aligned. We consider the ragged edges of the
// load command as defined, since they are mapped from the file.
seg_start = RoundDownTo(seg_start, GetPageSizeCached());
seg_end = RoundUpTo(seg_end, GetPageSizeCached());
cb((void *)seg_start, seg_end - seg_start);
}
}
}
#endif
#if defined(__x86_64__)
// We cannot use glibc's clone wrapper, because it messes with the child
// task's TLS. It writes the PID and TID of the child task to its thread
// descriptor, but in our case the child task shares the thread descriptor with
// the parent (because we don't know how to allocate a new thread
// descriptor to keep glibc happy). So the stock version of clone(), when
// used with CLONE_VM, would end up corrupting the parent's thread descriptor.
uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
int *parent_tidptr, void *newtls, int *child_tidptr) {
long long res;
if (!fn || !child_stack)
return -EINVAL;
CHECK_EQ(0, (uptr)child_stack % 16);
child_stack = (char *)child_stack - 2 * sizeof(void *);
((void **)child_stack)[0] = (void *)(uptr)fn;
((void **)child_stack)[1] = arg;
__asm__ __volatile__(
/* %rax = syscall(%rax = __NR_clone,
* %rdi = flags,
* %rsi = child_stack,
* %rdx = parent_tidptr,
* %r8 = new_tls,
* %r10 = child_tidptr)
*/
"movq %6,%%r8\n"
"movq %7,%%r10\n"
"syscall\n"
/* if (%rax != 0)
* return;
*/
"testq %%rax,%%rax\n"
"jnz 1f\n"
/* In the child. Terminate unwind chain. */
// XXX: We should also terminate the CFI unwind chain
// here. Unfortunately clang 3.2 doesn't support the
// necessary CFI directives, so we skip that part.
"xorq %%rbp,%%rbp\n"
/* Call "fn(arg)". */
"popq %%rax\n"
"popq %%rdi\n"
"call *%%rax\n"
/* Call _exit(%rax). */
"movq %%rax,%%rdi\n"
"movq %2,%%rax\n"
"syscall\n"
/* Return to parent. */
"1:\n"
: "=a" (res)
: "a"(__NR_clone), "i"(__NR_exit),
"S"(child_stack),
"D"(flags),
"d"(parent_tidptr),
"r"(newtls),
"r"(child_tidptr)
: "rsp", "memory", "r8", "r10", "r11", "rcx");
return res;
}
#endif // defined(__x86_64__)
} // namespace __sanitizer
#endif // SANITIZER_LINUX
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