sanitizer_linux.cc revision 0f7a2acb3326a5900d1a1339ebf959b14b372e0d
1//===-- sanitizer_linux.cc ------------------------------------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file is shared between AddressSanitizer and ThreadSanitizer 11// run-time libraries and implements linux-specific functions from 12// sanitizer_libc.h. 13//===----------------------------------------------------------------------===// 14 15#include "sanitizer_platform.h" 16#if SANITIZER_LINUX 17 18#include "sanitizer_common.h" 19#include "sanitizer_internal_defs.h" 20#include "sanitizer_libc.h" 21#include "sanitizer_linux.h" 22#include "sanitizer_mutex.h" 23#include "sanitizer_placement_new.h" 24#include "sanitizer_procmaps.h" 25#include "sanitizer_stacktrace.h" 26#include "sanitizer_symbolizer.h" 27 28#include <asm/param.h> 29#include <dlfcn.h> 30#include <errno.h> 31#include <fcntl.h> 32#if !SANITIZER_ANDROID 33#include <link.h> 34#endif 35#include <pthread.h> 36#include <sched.h> 37#include <sys/mman.h> 38#include <sys/ptrace.h> 39#include <sys/resource.h> 40#include <sys/stat.h> 41#include <sys/syscall.h> 42#include <sys/time.h> 43#include <sys/types.h> 44#include <unistd.h> 45#include <unwind.h> 46 47#if !SANITIZER_ANDROID 48#include <sys/signal.h> 49#endif 50 51// <linux/time.h> 52struct kernel_timeval { 53 long tv_sec; 54 long tv_usec; 55}; 56 57// <linux/futex.h> is broken on some linux distributions. 58const int FUTEX_WAIT = 0; 59const int FUTEX_WAKE = 1; 60 61// Are we using 32-bit or 64-bit syscalls? 62// x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 32 63// but it still needs to use 64-bit syscalls. 64#if defined(__x86_64__) || SANITIZER_WORDSIZE == 64 65# define SANITIZER_LINUX_USES_64BIT_SYSCALLS 1 66#else 67# define SANITIZER_LINUX_USES_64BIT_SYSCALLS 0 68#endif 69 70namespace __sanitizer { 71 72#ifdef __x86_64__ 73#include "sanitizer_syscall_linux_x86_64.inc" 74#else 75#include "sanitizer_syscall_generic.inc" 76#endif 77 78// --------------- sanitizer_libc.h 79uptr internal_mmap(void *addr, uptr length, int prot, int flags, 80 int fd, u64 offset) { 81#if SANITIZER_LINUX_USES_64BIT_SYSCALLS 82 return internal_syscall(__NR_mmap, addr, length, prot, flags, fd, offset); 83#else 84 return internal_syscall(__NR_mmap2, addr, length, prot, flags, fd, offset); 85#endif 86} 87 88uptr internal_munmap(void *addr, uptr length) { 89 return internal_syscall(__NR_munmap, addr, length); 90} 91 92uptr internal_close(fd_t fd) { 93 return internal_syscall(__NR_close, fd); 94} 95 96uptr internal_open(const char *filename, int flags) { 97 return internal_syscall(__NR_open, filename, flags); 98} 99 100uptr internal_open(const char *filename, int flags, u32 mode) { 101 return internal_syscall(__NR_open, filename, flags, mode); 102} 103 104uptr OpenFile(const char *filename, bool write) { 105 return internal_open(filename, 106 write ? O_WRONLY | O_CREAT /*| O_CLOEXEC*/ : O_RDONLY, 0660); 107} 108 109uptr internal_read(fd_t fd, void *buf, uptr count) { 110 sptr res; 111 HANDLE_EINTR(res, (sptr)internal_syscall(__NR_read, fd, buf, count)); 112 return res; 113} 114 115uptr internal_write(fd_t fd, const void *buf, uptr count) { 116 sptr res; 117 HANDLE_EINTR(res, (sptr)internal_syscall(__NR_write, fd, buf, count)); 118 return res; 119} 120 121#if !SANITIZER_LINUX_USES_64BIT_SYSCALLS 122static void stat64_to_stat(struct stat64 *in, struct stat *out) { 123 internal_memset(out, 0, sizeof(*out)); 124 out->st_dev = in->st_dev; 125 out->st_ino = in->st_ino; 126 out->st_mode = in->st_mode; 127 out->st_nlink = in->st_nlink; 128 out->st_uid = in->st_uid; 129 out->st_gid = in->st_gid; 130 out->st_rdev = in->st_rdev; 131 out->st_size = in->st_size; 132 out->st_blksize = in->st_blksize; 133 out->st_blocks = in->st_blocks; 134 out->st_atime = in->st_atime; 135 out->st_mtime = in->st_mtime; 136 out->st_ctime = in->st_ctime; 137 out->st_ino = in->st_ino; 138} 139#endif 140 141uptr internal_stat(const char *path, void *buf) { 142#if SANITIZER_LINUX_USES_64BIT_SYSCALLS 143 return internal_syscall(__NR_stat, path, buf); 144#else 145 struct stat64 buf64; 146 int res = internal_syscall(__NR_stat64, path, &buf64); 147 stat64_to_stat(&buf64, (struct stat *)buf); 148 return res; 149#endif 150} 151 152uptr internal_lstat(const char *path, void *buf) { 153#if SANITIZER_LINUX_USES_64BIT_SYSCALLS 154 return internal_syscall(__NR_lstat, path, buf); 155#else 156 struct stat64 buf64; 157 int res = internal_syscall(__NR_lstat64, path, &buf64); 158 stat64_to_stat(&buf64, (struct stat *)buf); 159 return res; 160#endif 161} 162 163uptr internal_fstat(fd_t fd, void *buf) { 164#if SANITIZER_LINUX_USES_64BIT_SYSCALLS 165 return internal_syscall(__NR_fstat, fd, buf); 166#else 167 struct stat64 buf64; 168 int res = internal_syscall(__NR_fstat64, fd, &buf64); 169 stat64_to_stat(&buf64, (struct stat *)buf); 170 return res; 171#endif 172} 173 174uptr internal_filesize(fd_t fd) { 175 struct stat st; 176 if (internal_fstat(fd, &st)) 177 return -1; 178 return (uptr)st.st_size; 179} 180 181uptr internal_dup2(int oldfd, int newfd) { 182 return internal_syscall(__NR_dup2, oldfd, newfd); 183} 184 185uptr internal_readlink(const char *path, char *buf, uptr bufsize) { 186 return internal_syscall(__NR_readlink, path, buf, bufsize); 187} 188 189uptr internal_unlink(const char *path) { 190 return internal_syscall(__NR_unlink, path); 191} 192 193uptr internal_sched_yield() { 194 return internal_syscall(__NR_sched_yield); 195} 196 197void internal__exit(int exitcode) { 198 internal_syscall(__NR_exit_group, exitcode); 199 Die(); // Unreachable. 200} 201 202uptr internal_execve(const char *filename, char *const argv[], 203 char *const envp[]) { 204 return internal_syscall(__NR_execve, filename, argv, envp); 205} 206 207// ----------------- sanitizer_common.h 208bool FileExists(const char *filename) { 209 struct stat st; 210 if (internal_stat(filename, &st)) 211 return false; 212 // Sanity check: filename is a regular file. 213 return S_ISREG(st.st_mode); 214} 215 216uptr GetTid() { 217 return internal_syscall(__NR_gettid); 218} 219 220u64 NanoTime() { 221 kernel_timeval tv = {}; 222 internal_syscall(__NR_gettimeofday, &tv, 0); 223 return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000; 224} 225 226// Like getenv, but reads env directly from /proc and does not use libc. 227// This function should be called first inside __asan_init. 228const char *GetEnv(const char *name) { 229 static char *environ; 230 static uptr len; 231 static bool inited; 232 if (!inited) { 233 inited = true; 234 uptr environ_size; 235 len = ReadFileToBuffer("/proc/self/environ", 236 &environ, &environ_size, 1 << 26); 237 } 238 if (!environ || len == 0) return 0; 239 uptr namelen = internal_strlen(name); 240 const char *p = environ; 241 while (*p != '\0') { // will happen at the \0\0 that terminates the buffer 242 // proc file has the format NAME=value\0NAME=value\0NAME=value\0... 243 const char* endp = 244 (char*)internal_memchr(p, '\0', len - (p - environ)); 245 if (endp == 0) // this entry isn't NUL terminated 246 return 0; 247 else if (!internal_memcmp(p, name, namelen) && p[namelen] == '=') // Match. 248 return p + namelen + 1; // point after = 249 p = endp + 1; 250 } 251 return 0; // Not found. 252} 253 254extern "C" { 255 SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end; 256} 257 258#if !SANITIZER_GO 259static void ReadNullSepFileToArray(const char *path, char ***arr, 260 int arr_size) { 261 char *buff; 262 uptr buff_size = 0; 263 *arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray"); 264 ReadFileToBuffer(path, &buff, &buff_size, 1024 * 1024); 265 (*arr)[0] = buff; 266 int count, i; 267 for (count = 1, i = 1; ; i++) { 268 if (buff[i] == 0) { 269 if (buff[i+1] == 0) break; 270 (*arr)[count] = &buff[i+1]; 271 CHECK_LE(count, arr_size - 1); // FIXME: make this more flexible. 272 count++; 273 } 274 } 275 (*arr)[count] = 0; 276} 277#endif 278 279static void GetArgsAndEnv(char*** argv, char*** envp) { 280#if !SANITIZER_GO 281 if (&__libc_stack_end) { 282#endif 283 uptr* stack_end = (uptr*)__libc_stack_end; 284 int argc = *stack_end; 285 *argv = (char**)(stack_end + 1); 286 *envp = (char**)(stack_end + argc + 2); 287#if !SANITIZER_GO 288 } else { 289 static const int kMaxArgv = 2000, kMaxEnvp = 2000; 290 ReadNullSepFileToArray("/proc/self/cmdline", argv, kMaxArgv); 291 ReadNullSepFileToArray("/proc/self/environ", envp, kMaxEnvp); 292 } 293#endif 294} 295 296void ReExec() { 297 char **argv, **envp; 298 GetArgsAndEnv(&argv, &envp); 299 uptr rv = internal_execve("/proc/self/exe", argv, envp); 300 int rverrno; 301 CHECK_EQ(internal_iserror(rv, &rverrno), true); 302 Printf("execve failed, errno %d\n", rverrno); 303 Die(); 304} 305 306void PrepareForSandboxing() { 307 // Some kinds of sandboxes may forbid filesystem access, so we won't be able 308 // to read the file mappings from /proc/self/maps. Luckily, neither the 309 // process will be able to load additional libraries, so it's fine to use the 310 // cached mappings. 311 MemoryMappingLayout::CacheMemoryMappings(); 312 // Same for /proc/self/exe in the symbolizer. 313#if !SANITIZER_GO 314 getSymbolizer()->PrepareForSandboxing(); 315#endif 316} 317 318// ----------------- sanitizer_procmaps.h 319// Linker initialized. 320ProcSelfMapsBuff MemoryMappingLayout::cached_proc_self_maps_; 321StaticSpinMutex MemoryMappingLayout::cache_lock_; // Linker initialized. 322 323MemoryMappingLayout::MemoryMappingLayout(bool cache_enabled) { 324 proc_self_maps_.len = 325 ReadFileToBuffer("/proc/self/maps", &proc_self_maps_.data, 326 &proc_self_maps_.mmaped_size, 1 << 26); 327 if (cache_enabled) { 328 if (proc_self_maps_.mmaped_size == 0) { 329 LoadFromCache(); 330 CHECK_GT(proc_self_maps_.len, 0); 331 } 332 } else { 333 CHECK_GT(proc_self_maps_.mmaped_size, 0); 334 } 335 Reset(); 336 // FIXME: in the future we may want to cache the mappings on demand only. 337 if (cache_enabled) 338 CacheMemoryMappings(); 339} 340 341MemoryMappingLayout::~MemoryMappingLayout() { 342 // Only unmap the buffer if it is different from the cached one. Otherwise 343 // it will be unmapped when the cache is refreshed. 344 if (proc_self_maps_.data != cached_proc_self_maps_.data) { 345 UnmapOrDie(proc_self_maps_.data, proc_self_maps_.mmaped_size); 346 } 347} 348 349void MemoryMappingLayout::Reset() { 350 current_ = proc_self_maps_.data; 351} 352 353// static 354void MemoryMappingLayout::CacheMemoryMappings() { 355 SpinMutexLock l(&cache_lock_); 356 // Don't invalidate the cache if the mappings are unavailable. 357 ProcSelfMapsBuff old_proc_self_maps; 358 old_proc_self_maps = cached_proc_self_maps_; 359 cached_proc_self_maps_.len = 360 ReadFileToBuffer("/proc/self/maps", &cached_proc_self_maps_.data, 361 &cached_proc_self_maps_.mmaped_size, 1 << 26); 362 if (cached_proc_self_maps_.mmaped_size == 0) { 363 cached_proc_self_maps_ = old_proc_self_maps; 364 } else { 365 if (old_proc_self_maps.mmaped_size) { 366 UnmapOrDie(old_proc_self_maps.data, 367 old_proc_self_maps.mmaped_size); 368 } 369 } 370} 371 372void MemoryMappingLayout::LoadFromCache() { 373 SpinMutexLock l(&cache_lock_); 374 if (cached_proc_self_maps_.data) { 375 proc_self_maps_ = cached_proc_self_maps_; 376 } 377} 378 379// Parse a hex value in str and update str. 380static uptr ParseHex(char **str) { 381 uptr x = 0; 382 char *s; 383 for (s = *str; ; s++) { 384 char c = *s; 385 uptr v = 0; 386 if (c >= '0' && c <= '9') 387 v = c - '0'; 388 else if (c >= 'a' && c <= 'f') 389 v = c - 'a' + 10; 390 else if (c >= 'A' && c <= 'F') 391 v = c - 'A' + 10; 392 else 393 break; 394 x = x * 16 + v; 395 } 396 *str = s; 397 return x; 398} 399 400static bool IsOneOf(char c, char c1, char c2) { 401 return c == c1 || c == c2; 402} 403 404static bool IsDecimal(char c) { 405 return c >= '0' && c <= '9'; 406} 407 408static bool IsHex(char c) { 409 return (c >= '0' && c <= '9') 410 || (c >= 'a' && c <= 'f'); 411} 412 413static uptr ReadHex(const char *p) { 414 uptr v = 0; 415 for (; IsHex(p[0]); p++) { 416 if (p[0] >= '0' && p[0] <= '9') 417 v = v * 16 + p[0] - '0'; 418 else 419 v = v * 16 + p[0] - 'a' + 10; 420 } 421 return v; 422} 423 424static uptr ReadDecimal(const char *p) { 425 uptr v = 0; 426 for (; IsDecimal(p[0]); p++) 427 v = v * 10 + p[0] - '0'; 428 return v; 429} 430 431 432bool MemoryMappingLayout::Next(uptr *start, uptr *end, uptr *offset, 433 char filename[], uptr filename_size, 434 uptr *protection) { 435 char *last = proc_self_maps_.data + proc_self_maps_.len; 436 if (current_ >= last) return false; 437 uptr dummy; 438 if (!start) start = &dummy; 439 if (!end) end = &dummy; 440 if (!offset) offset = &dummy; 441 char *next_line = (char*)internal_memchr(current_, '\n', last - current_); 442 if (next_line == 0) 443 next_line = last; 444 // Example: 08048000-08056000 r-xp 00000000 03:0c 64593 /foo/bar 445 *start = ParseHex(¤t_); 446 CHECK_EQ(*current_++, '-'); 447 *end = ParseHex(¤t_); 448 CHECK_EQ(*current_++, ' '); 449 uptr local_protection = 0; 450 CHECK(IsOneOf(*current_, '-', 'r')); 451 if (*current_++ == 'r') 452 local_protection |= kProtectionRead; 453 CHECK(IsOneOf(*current_, '-', 'w')); 454 if (*current_++ == 'w') 455 local_protection |= kProtectionWrite; 456 CHECK(IsOneOf(*current_, '-', 'x')); 457 if (*current_++ == 'x') 458 local_protection |= kProtectionExecute; 459 CHECK(IsOneOf(*current_, 's', 'p')); 460 if (*current_++ == 's') 461 local_protection |= kProtectionShared; 462 if (protection) { 463 *protection = local_protection; 464 } 465 CHECK_EQ(*current_++, ' '); 466 *offset = ParseHex(¤t_); 467 CHECK_EQ(*current_++, ' '); 468 ParseHex(¤t_); 469 CHECK_EQ(*current_++, ':'); 470 ParseHex(¤t_); 471 CHECK_EQ(*current_++, ' '); 472 while (IsDecimal(*current_)) 473 current_++; 474 // Qemu may lack the trailing space. 475 // http://code.google.com/p/address-sanitizer/issues/detail?id=160 476 // CHECK_EQ(*current_++, ' '); 477 // Skip spaces. 478 while (current_ < next_line && *current_ == ' ') 479 current_++; 480 // Fill in the filename. 481 uptr i = 0; 482 while (current_ < next_line) { 483 if (filename && i < filename_size - 1) 484 filename[i++] = *current_; 485 current_++; 486 } 487 if (filename && i < filename_size) 488 filename[i] = 0; 489 current_ = next_line + 1; 490 return true; 491} 492 493// Gets the object name and the offset by walking MemoryMappingLayout. 494bool MemoryMappingLayout::GetObjectNameAndOffset(uptr addr, uptr *offset, 495 char filename[], 496 uptr filename_size, 497 uptr *protection) { 498 return IterateForObjectNameAndOffset(addr, offset, filename, filename_size, 499 protection); 500} 501 502void GetMemoryProfile(fill_profile_f cb, uptr *stats, uptr stats_size) { 503 char *smaps = 0; 504 uptr smaps_cap = 0; 505 uptr smaps_len = ReadFileToBuffer("/proc/self/smaps", 506 &smaps, &smaps_cap, 64<<20); 507 uptr start = 0; 508 bool file = false; 509 const char *pos = smaps; 510 while (pos < smaps + smaps_len) { 511 if (IsHex(pos[0])) { 512 start = ReadHex(pos); 513 for (; *pos != '/' && *pos > '\n'; pos++) {} 514 file = *pos == '/'; 515 } else if (internal_strncmp(pos, "Rss:", 4) == 0) { 516 for (; *pos < '0' || *pos > '9'; pos++) {} 517 uptr rss = ReadDecimal(pos) * 1024; 518 cb(start, rss, file, stats, stats_size); 519 } 520 while (*pos++ != '\n') {} 521 } 522 UnmapOrDie(smaps, smaps_cap); 523} 524 525enum MutexState { 526 MtxUnlocked = 0, 527 MtxLocked = 1, 528 MtxSleeping = 2 529}; 530 531BlockingMutex::BlockingMutex(LinkerInitialized) { 532 CHECK_EQ(owner_, 0); 533} 534 535BlockingMutex::BlockingMutex() { 536 internal_memset(this, 0, sizeof(*this)); 537} 538 539void BlockingMutex::Lock() { 540 atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_); 541 if (atomic_exchange(m, MtxLocked, memory_order_acquire) == MtxUnlocked) 542 return; 543 while (atomic_exchange(m, MtxSleeping, memory_order_acquire) != MtxUnlocked) 544 internal_syscall(__NR_futex, m, FUTEX_WAIT, MtxSleeping, 0, 0, 0); 545} 546 547void BlockingMutex::Unlock() { 548 atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_); 549 u32 v = atomic_exchange(m, MtxUnlocked, memory_order_relaxed); 550 CHECK_NE(v, MtxUnlocked); 551 if (v == MtxSleeping) 552 internal_syscall(__NR_futex, m, FUTEX_WAKE, 1, 0, 0, 0); 553} 554 555void BlockingMutex::CheckLocked() { 556 atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_); 557 CHECK_NE(MtxUnlocked, atomic_load(m, memory_order_relaxed)); 558} 559 560// ----------------- sanitizer_linux.h 561// The actual size of this structure is specified by d_reclen. 562// Note that getdents64 uses a different structure format. We only provide the 563// 32-bit syscall here. 564struct linux_dirent { 565 unsigned long d_ino; 566 unsigned long d_off; 567 unsigned short d_reclen; 568 char d_name[256]; 569}; 570 571// Syscall wrappers. 572uptr internal_ptrace(int request, int pid, void *addr, void *data) { 573 return internal_syscall(__NR_ptrace, request, pid, addr, data); 574} 575 576uptr internal_waitpid(int pid, int *status, int options) { 577 return internal_syscall(__NR_wait4, pid, status, options, 0 /* rusage */); 578} 579 580uptr internal_getpid() { 581 return internal_syscall(__NR_getpid); 582} 583 584uptr internal_getppid() { 585 return internal_syscall(__NR_getppid); 586} 587 588uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) { 589 return internal_syscall(__NR_getdents, fd, dirp, count); 590} 591 592uptr internal_lseek(fd_t fd, OFF_T offset, int whence) { 593 return internal_syscall(__NR_lseek, fd, offset, whence); 594} 595 596uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) { 597 return internal_syscall(__NR_prctl, option, arg2, arg3, arg4, arg5); 598} 599 600uptr internal_sigaltstack(const struct sigaltstack *ss, 601 struct sigaltstack *oss) { 602 return internal_syscall(__NR_sigaltstack, ss, oss); 603} 604 605uptr internal_sigaction(int signum, const kernel_sigaction_t *act, 606 struct kernel_sigaction_t *oldact) { 607 return internal_syscall(__NR_rt_sigaction, signum, act, oldact, 608 sizeof(kernel_sigset_t)); 609} 610 611uptr internal_sigprocmask(int how, kernel_sigset_t *set, 612 kernel_sigset_t *oldset) { 613 return internal_syscall(__NR_rt_sigprocmask, (uptr)how, &set->sig[0], 614 &oldset->sig[0], sizeof(kernel_sigset_t)); 615} 616 617void internal_sigfillset(kernel_sigset_t *set) { 618 internal_memset(set, 0xff, sizeof(*set)); 619} 620 621void internal_sigdelset(kernel_sigset_t *set, int signum) { 622 signum -= 1; 623 CHECK_GE(signum, 0); 624 CHECK_LT(signum, sizeof(*set) * 8); 625 const uptr idx = signum / (sizeof(set->sig[0]) * 8); 626 const uptr bit = signum % (sizeof(set->sig[0]) * 8); 627 set->sig[idx] &= ~(1 << bit); 628} 629 630// ThreadLister implementation. 631ThreadLister::ThreadLister(int pid) 632 : pid_(pid), 633 descriptor_(-1), 634 buffer_(4096), 635 error_(true), 636 entry_((struct linux_dirent *)buffer_.data()), 637 bytes_read_(0) { 638 char task_directory_path[80]; 639 internal_snprintf(task_directory_path, sizeof(task_directory_path), 640 "/proc/%d/task/", pid); 641 uptr openrv = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY); 642 if (internal_iserror(openrv)) { 643 error_ = true; 644 Report("Can't open /proc/%d/task for reading.\n", pid); 645 } else { 646 error_ = false; 647 descriptor_ = openrv; 648 } 649} 650 651int ThreadLister::GetNextTID() { 652 int tid = -1; 653 do { 654 if (error_) 655 return -1; 656 if ((char *)entry_ >= &buffer_[bytes_read_] && !GetDirectoryEntries()) 657 return -1; 658 if (entry_->d_ino != 0 && entry_->d_name[0] >= '0' && 659 entry_->d_name[0] <= '9') { 660 // Found a valid tid. 661 tid = (int)internal_atoll(entry_->d_name); 662 } 663 entry_ = (struct linux_dirent *)(((char *)entry_) + entry_->d_reclen); 664 } while (tid < 0); 665 return tid; 666} 667 668void ThreadLister::Reset() { 669 if (error_ || descriptor_ < 0) 670 return; 671 internal_lseek(descriptor_, 0, SEEK_SET); 672} 673 674ThreadLister::~ThreadLister() { 675 if (descriptor_ >= 0) 676 internal_close(descriptor_); 677} 678 679bool ThreadLister::error() { return error_; } 680 681bool ThreadLister::GetDirectoryEntries() { 682 CHECK_GE(descriptor_, 0); 683 CHECK_NE(error_, true); 684 bytes_read_ = internal_getdents(descriptor_, 685 (struct linux_dirent *)buffer_.data(), 686 buffer_.size()); 687 if (internal_iserror(bytes_read_)) { 688 Report("Can't read directory entries from /proc/%d/task.\n", pid_); 689 error_ = true; 690 return false; 691 } else if (bytes_read_ == 0) { 692 return false; 693 } 694 entry_ = (struct linux_dirent *)buffer_.data(); 695 return true; 696} 697 698uptr GetPageSize() { 699#if defined(__x86_64__) || defined(__i386__) 700 return EXEC_PAGESIZE; 701#else 702 return sysconf(_SC_PAGESIZE); // EXEC_PAGESIZE may not be trustworthy. 703#endif 704} 705 706static char proc_self_exe_cache_str[kMaxPathLength]; 707static uptr proc_self_exe_cache_len = 0; 708 709uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) { 710 uptr module_name_len = internal_readlink( 711 "/proc/self/exe", buf, buf_len); 712 int readlink_error; 713 if (internal_iserror(module_name_len, &readlink_error)) { 714 if (proc_self_exe_cache_len) { 715 // If available, use the cached module name. 716 CHECK_LE(proc_self_exe_cache_len, buf_len); 717 internal_strncpy(buf, proc_self_exe_cache_str, buf_len); 718 module_name_len = internal_strlen(proc_self_exe_cache_str); 719 } else { 720 // We can't read /proc/self/exe for some reason, assume the name of the 721 // binary is unknown. 722 Report("WARNING: readlink(\"/proc/self/exe\") failed with errno %d, " 723 "some stack frames may not be symbolized\n", readlink_error); 724 module_name_len = internal_snprintf(buf, buf_len, "/proc/self/exe"); 725 } 726 CHECK_LT(module_name_len, buf_len); 727 buf[module_name_len] = '\0'; 728 } 729 return module_name_len; 730} 731 732void CacheBinaryName() { 733 if (!proc_self_exe_cache_len) { 734 proc_self_exe_cache_len = 735 ReadBinaryName(proc_self_exe_cache_str, kMaxPathLength); 736 } 737} 738 739// Match full names of the form /path/to/base_name{-,.}* 740bool LibraryNameIs(const char *full_name, const char *base_name) { 741 const char *name = full_name; 742 // Strip path. 743 while (*name != '\0') name++; 744 while (name > full_name && *name != '/') name--; 745 if (*name == '/') name++; 746 uptr base_name_length = internal_strlen(base_name); 747 if (internal_strncmp(name, base_name, base_name_length)) return false; 748 return (name[base_name_length] == '-' || name[base_name_length] == '.'); 749} 750 751#if !SANITIZER_ANDROID 752// Call cb for each region mapped by map. 753void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) { 754 typedef ElfW(Phdr) Elf_Phdr; 755 typedef ElfW(Ehdr) Elf_Ehdr; 756 char *base = (char *)map->l_addr; 757 Elf_Ehdr *ehdr = (Elf_Ehdr *)base; 758 char *phdrs = base + ehdr->e_phoff; 759 char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize; 760 761 // Find the segment with the minimum base so we can "relocate" the p_vaddr 762 // fields. Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC 763 // objects have a non-zero base. 764 uptr preferred_base = (uptr)-1; 765 for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) { 766 Elf_Phdr *phdr = (Elf_Phdr *)iter; 767 if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr) 768 preferred_base = (uptr)phdr->p_vaddr; 769 } 770 771 // Compute the delta from the real base to get a relocation delta. 772 sptr delta = (uptr)base - preferred_base; 773 // Now we can figure out what the loader really mapped. 774 for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) { 775 Elf_Phdr *phdr = (Elf_Phdr *)iter; 776 if (phdr->p_type == PT_LOAD) { 777 uptr seg_start = phdr->p_vaddr + delta; 778 uptr seg_end = seg_start + phdr->p_memsz; 779 // None of these values are aligned. We consider the ragged edges of the 780 // load command as defined, since they are mapped from the file. 781 seg_start = RoundDownTo(seg_start, GetPageSizeCached()); 782 seg_end = RoundUpTo(seg_end, GetPageSizeCached()); 783 cb((void *)seg_start, seg_end - seg_start); 784 } 785 } 786} 787#endif 788 789#if defined(__x86_64__) 790// We cannot use glibc's clone wrapper, because it messes with the child 791// task's TLS. It writes the PID and TID of the child task to its thread 792// descriptor, but in our case the child task shares the thread descriptor with 793// the parent (because we don't know how to allocate a new thread 794// descriptor to keep glibc happy). So the stock version of clone(), when 795// used with CLONE_VM, would end up corrupting the parent's thread descriptor. 796uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg, 797 int *parent_tidptr, void *newtls, int *child_tidptr) { 798 long long res; 799 if (!fn || !child_stack) 800 return -EINVAL; 801 CHECK_EQ(0, (uptr)child_stack % 16); 802 child_stack = (char *)child_stack - 2 * sizeof(void *); 803 ((void **)child_stack)[0] = (void *)(uptr)fn; 804 ((void **)child_stack)[1] = arg; 805 __asm__ __volatile__( 806 /* %rax = syscall(%rax = __NR_clone, 807 * %rdi = flags, 808 * %rsi = child_stack, 809 * %rdx = parent_tidptr, 810 * %r8 = new_tls, 811 * %r10 = child_tidptr) 812 */ 813 "movq %6,%%r8\n" 814 "movq %7,%%r10\n" 815 "syscall\n" 816 817 /* if (%rax != 0) 818 * return; 819 */ 820 "testq %%rax,%%rax\n" 821 "jnz 1f\n" 822 823 /* In the child. Terminate unwind chain. */ 824 // XXX: We should also terminate the CFI unwind chain 825 // here. Unfortunately clang 3.2 doesn't support the 826 // necessary CFI directives, so we skip that part. 827 "xorq %%rbp,%%rbp\n" 828 829 /* Call "fn(arg)". */ 830 "popq %%rax\n" 831 "popq %%rdi\n" 832 "call *%%rax\n" 833 834 /* Call _exit(%rax). */ 835 "movq %%rax,%%rdi\n" 836 "movq %2,%%rax\n" 837 "syscall\n" 838 839 /* Return to parent. */ 840 "1:\n" 841 : "=a" (res) 842 : "a"(__NR_clone), "i"(__NR_exit), 843 "S"(child_stack), 844 "D"(flags), 845 "d"(parent_tidptr), 846 "r"(newtls), 847 "r"(child_tidptr) 848 : "rsp", "memory", "r8", "r10", "r11", "rcx"); 849 return res; 850} 851#endif // defined(__x86_64__) 852} // namespace __sanitizer 853 854#endif // SANITIZER_LINUX 855