sanitizer_linux.cc revision 2e13ca86c9ce926e6fefd528892592326478ac6c
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 SymbolizerPrepareForSandboxing(); 314} 315 316// ----------------- sanitizer_procmaps.h 317// Linker initialized. 318ProcSelfMapsBuff MemoryMappingLayout::cached_proc_self_maps_; 319StaticSpinMutex MemoryMappingLayout::cache_lock_; // Linker initialized. 320 321MemoryMappingLayout::MemoryMappingLayout(bool cache_enabled) { 322 proc_self_maps_.len = 323 ReadFileToBuffer("/proc/self/maps", &proc_self_maps_.data, 324 &proc_self_maps_.mmaped_size, 1 << 26); 325 if (cache_enabled) { 326 if (proc_self_maps_.mmaped_size == 0) { 327 LoadFromCache(); 328 CHECK_GT(proc_self_maps_.len, 0); 329 } 330 } else { 331 CHECK_GT(proc_self_maps_.mmaped_size, 0); 332 } 333 Reset(); 334 // FIXME: in the future we may want to cache the mappings on demand only. 335 if (cache_enabled) 336 CacheMemoryMappings(); 337} 338 339MemoryMappingLayout::~MemoryMappingLayout() { 340 // Only unmap the buffer if it is different from the cached one. Otherwise 341 // it will be unmapped when the cache is refreshed. 342 if (proc_self_maps_.data != cached_proc_self_maps_.data) { 343 UnmapOrDie(proc_self_maps_.data, proc_self_maps_.mmaped_size); 344 } 345} 346 347void MemoryMappingLayout::Reset() { 348 current_ = proc_self_maps_.data; 349} 350 351// static 352void MemoryMappingLayout::CacheMemoryMappings() { 353 SpinMutexLock l(&cache_lock_); 354 // Don't invalidate the cache if the mappings are unavailable. 355 ProcSelfMapsBuff old_proc_self_maps; 356 old_proc_self_maps = cached_proc_self_maps_; 357 cached_proc_self_maps_.len = 358 ReadFileToBuffer("/proc/self/maps", &cached_proc_self_maps_.data, 359 &cached_proc_self_maps_.mmaped_size, 1 << 26); 360 if (cached_proc_self_maps_.mmaped_size == 0) { 361 cached_proc_self_maps_ = old_proc_self_maps; 362 } else { 363 if (old_proc_self_maps.mmaped_size) { 364 UnmapOrDie(old_proc_self_maps.data, 365 old_proc_self_maps.mmaped_size); 366 } 367 } 368} 369 370void MemoryMappingLayout::LoadFromCache() { 371 SpinMutexLock l(&cache_lock_); 372 if (cached_proc_self_maps_.data) { 373 proc_self_maps_ = cached_proc_self_maps_; 374 } 375} 376 377// Parse a hex value in str and update str. 378static uptr ParseHex(char **str) { 379 uptr x = 0; 380 char *s; 381 for (s = *str; ; s++) { 382 char c = *s; 383 uptr v = 0; 384 if (c >= '0' && c <= '9') 385 v = c - '0'; 386 else if (c >= 'a' && c <= 'f') 387 v = c - 'a' + 10; 388 else if (c >= 'A' && c <= 'F') 389 v = c - 'A' + 10; 390 else 391 break; 392 x = x * 16 + v; 393 } 394 *str = s; 395 return x; 396} 397 398static bool IsOneOf(char c, char c1, char c2) { 399 return c == c1 || c == c2; 400} 401 402static bool IsDecimal(char c) { 403 return c >= '0' && c <= '9'; 404} 405 406static bool IsHex(char c) { 407 return (c >= '0' && c <= '9') 408 || (c >= 'a' && c <= 'f'); 409} 410 411static uptr ReadHex(const char *p) { 412 uptr v = 0; 413 for (; IsHex(p[0]); p++) { 414 if (p[0] >= '0' && p[0] <= '9') 415 v = v * 16 + p[0] - '0'; 416 else 417 v = v * 16 + p[0] - 'a' + 10; 418 } 419 return v; 420} 421 422static uptr ReadDecimal(const char *p) { 423 uptr v = 0; 424 for (; IsDecimal(p[0]); p++) 425 v = v * 10 + p[0] - '0'; 426 return v; 427} 428 429 430bool MemoryMappingLayout::Next(uptr *start, uptr *end, uptr *offset, 431 char filename[], uptr filename_size, 432 uptr *protection) { 433 char *last = proc_self_maps_.data + proc_self_maps_.len; 434 if (current_ >= last) return false; 435 uptr dummy; 436 if (!start) start = &dummy; 437 if (!end) end = &dummy; 438 if (!offset) offset = &dummy; 439 char *next_line = (char*)internal_memchr(current_, '\n', last - current_); 440 if (next_line == 0) 441 next_line = last; 442 // Example: 08048000-08056000 r-xp 00000000 03:0c 64593 /foo/bar 443 *start = ParseHex(¤t_); 444 CHECK_EQ(*current_++, '-'); 445 *end = ParseHex(¤t_); 446 CHECK_EQ(*current_++, ' '); 447 uptr local_protection = 0; 448 CHECK(IsOneOf(*current_, '-', 'r')); 449 if (*current_++ == 'r') 450 local_protection |= kProtectionRead; 451 CHECK(IsOneOf(*current_, '-', 'w')); 452 if (*current_++ == 'w') 453 local_protection |= kProtectionWrite; 454 CHECK(IsOneOf(*current_, '-', 'x')); 455 if (*current_++ == 'x') 456 local_protection |= kProtectionExecute; 457 CHECK(IsOneOf(*current_, 's', 'p')); 458 if (*current_++ == 's') 459 local_protection |= kProtectionShared; 460 if (protection) { 461 *protection = local_protection; 462 } 463 CHECK_EQ(*current_++, ' '); 464 *offset = ParseHex(¤t_); 465 CHECK_EQ(*current_++, ' '); 466 ParseHex(¤t_); 467 CHECK_EQ(*current_++, ':'); 468 ParseHex(¤t_); 469 CHECK_EQ(*current_++, ' '); 470 while (IsDecimal(*current_)) 471 current_++; 472 // Qemu may lack the trailing space. 473 // http://code.google.com/p/address-sanitizer/issues/detail?id=160 474 // CHECK_EQ(*current_++, ' '); 475 // Skip spaces. 476 while (current_ < next_line && *current_ == ' ') 477 current_++; 478 // Fill in the filename. 479 uptr i = 0; 480 while (current_ < next_line) { 481 if (filename && i < filename_size - 1) 482 filename[i++] = *current_; 483 current_++; 484 } 485 if (filename && i < filename_size) 486 filename[i] = 0; 487 current_ = next_line + 1; 488 return true; 489} 490 491// Gets the object name and the offset by walking MemoryMappingLayout. 492bool MemoryMappingLayout::GetObjectNameAndOffset(uptr addr, uptr *offset, 493 char filename[], 494 uptr filename_size, 495 uptr *protection) { 496 return IterateForObjectNameAndOffset(addr, offset, filename, filename_size, 497 protection); 498} 499 500void GetMemoryProfile(fill_profile_f cb, uptr *stats, uptr stats_size) { 501 char *smaps = 0; 502 uptr smaps_cap = 0; 503 uptr smaps_len = ReadFileToBuffer("/proc/self/smaps", 504 &smaps, &smaps_cap, 64<<20); 505 uptr total = 0; 506 uptr start = 0; 507 bool file = false; 508 const char *pos = smaps; 509 while (pos < smaps + smaps_len) { 510 if (IsHex(pos[0])) { 511 start = ReadHex(pos); 512 for (; *pos != '/' && *pos > '\n'; pos++) {} 513 file = *pos == '/'; 514 } else if (internal_strncmp(pos, "Rss:", 4) == 0) { 515 for (; *pos < '0' || *pos > '9'; pos++) {} 516 uptr rss = ReadDecimal(pos) * 1024; 517 cb(start, rss, file, stats, stats_size); 518 } 519 while (*pos++ != '\n') {} 520 } 521 UnmapOrDie(smaps, smaps_cap); 522} 523 524enum MutexState { 525 MtxUnlocked = 0, 526 MtxLocked = 1, 527 MtxSleeping = 2 528}; 529 530BlockingMutex::BlockingMutex(LinkerInitialized) { 531 CHECK_EQ(owner_, 0); 532} 533 534BlockingMutex::BlockingMutex() { 535 internal_memset(this, 0, sizeof(*this)); 536} 537 538void BlockingMutex::Lock() { 539 atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_); 540 if (atomic_exchange(m, MtxLocked, memory_order_acquire) == MtxUnlocked) 541 return; 542 while (atomic_exchange(m, MtxSleeping, memory_order_acquire) != MtxUnlocked) 543 internal_syscall(__NR_futex, m, FUTEX_WAIT, MtxSleeping, 0, 0, 0); 544} 545 546void BlockingMutex::Unlock() { 547 atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_); 548 u32 v = atomic_exchange(m, MtxUnlocked, memory_order_relaxed); 549 CHECK_NE(v, MtxUnlocked); 550 if (v == MtxSleeping) 551 internal_syscall(__NR_futex, m, FUTEX_WAKE, 1, 0, 0, 0); 552} 553 554void BlockingMutex::CheckLocked() { 555 atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_); 556 CHECK_NE(MtxUnlocked, atomic_load(m, memory_order_relaxed)); 557} 558 559// ----------------- sanitizer_linux.h 560// The actual size of this structure is specified by d_reclen. 561// Note that getdents64 uses a different structure format. We only provide the 562// 32-bit syscall here. 563struct linux_dirent { 564 unsigned long d_ino; 565 unsigned long d_off; 566 unsigned short d_reclen; 567 char d_name[256]; 568}; 569 570// Syscall wrappers. 571uptr internal_ptrace(int request, int pid, void *addr, void *data) { 572 return internal_syscall(__NR_ptrace, request, pid, addr, data); 573} 574 575uptr internal_waitpid(int pid, int *status, int options) { 576 return internal_syscall(__NR_wait4, pid, status, options, 0 /* rusage */); 577} 578 579uptr internal_getpid() { 580 return internal_syscall(__NR_getpid); 581} 582 583uptr internal_getppid() { 584 return internal_syscall(__NR_getppid); 585} 586 587uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) { 588 return internal_syscall(__NR_getdents, fd, dirp, count); 589} 590 591uptr internal_lseek(fd_t fd, OFF_T offset, int whence) { 592 return internal_syscall(__NR_lseek, fd, offset, whence); 593} 594 595uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) { 596 return internal_syscall(__NR_prctl, option, arg2, arg3, arg4, arg5); 597} 598 599uptr internal_sigaltstack(const struct sigaltstack *ss, 600 struct sigaltstack *oss) { 601 return internal_syscall(__NR_sigaltstack, ss, oss); 602} 603 604// ThreadLister implementation. 605ThreadLister::ThreadLister(int pid) 606 : pid_(pid), 607 descriptor_(-1), 608 buffer_(4096), 609 error_(true), 610 entry_((struct linux_dirent *)buffer_.data()), 611 bytes_read_(0) { 612 char task_directory_path[80]; 613 internal_snprintf(task_directory_path, sizeof(task_directory_path), 614 "/proc/%d/task/", pid); 615 uptr openrv = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY); 616 if (internal_iserror(openrv)) { 617 error_ = true; 618 Report("Can't open /proc/%d/task for reading.\n", pid); 619 } else { 620 error_ = false; 621 descriptor_ = openrv; 622 } 623} 624 625int ThreadLister::GetNextTID() { 626 int tid = -1; 627 do { 628 if (error_) 629 return -1; 630 if ((char *)entry_ >= &buffer_[bytes_read_] && !GetDirectoryEntries()) 631 return -1; 632 if (entry_->d_ino != 0 && entry_->d_name[0] >= '0' && 633 entry_->d_name[0] <= '9') { 634 // Found a valid tid. 635 tid = (int)internal_atoll(entry_->d_name); 636 } 637 entry_ = (struct linux_dirent *)(((char *)entry_) + entry_->d_reclen); 638 } while (tid < 0); 639 return tid; 640} 641 642void ThreadLister::Reset() { 643 if (error_ || descriptor_ < 0) 644 return; 645 internal_lseek(descriptor_, 0, SEEK_SET); 646} 647 648ThreadLister::~ThreadLister() { 649 if (descriptor_ >= 0) 650 internal_close(descriptor_); 651} 652 653bool ThreadLister::error() { return error_; } 654 655bool ThreadLister::GetDirectoryEntries() { 656 CHECK_GE(descriptor_, 0); 657 CHECK_NE(error_, true); 658 bytes_read_ = internal_getdents(descriptor_, 659 (struct linux_dirent *)buffer_.data(), 660 buffer_.size()); 661 if (internal_iserror(bytes_read_)) { 662 Report("Can't read directory entries from /proc/%d/task.\n", pid_); 663 error_ = true; 664 return false; 665 } else if (bytes_read_ == 0) { 666 return false; 667 } 668 entry_ = (struct linux_dirent *)buffer_.data(); 669 return true; 670} 671 672uptr GetPageSize() { 673#if defined(__x86_64__) || defined(__i386__) 674 return EXEC_PAGESIZE; 675#else 676 return sysconf(_SC_PAGESIZE); // EXEC_PAGESIZE may not be trustworthy. 677#endif 678} 679 680// Match full names of the form /path/to/base_name{-,.}* 681bool LibraryNameIs(const char *full_name, const char *base_name) { 682 const char *name = full_name; 683 // Strip path. 684 while (*name != '\0') name++; 685 while (name > full_name && *name != '/') name--; 686 if (*name == '/') name++; 687 uptr base_name_length = internal_strlen(base_name); 688 if (internal_strncmp(name, base_name, base_name_length)) return false; 689 return (name[base_name_length] == '-' || name[base_name_length] == '.'); 690} 691 692#if !SANITIZER_ANDROID 693// Call cb for each region mapped by map. 694void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) { 695 typedef ElfW(Phdr) Elf_Phdr; 696 typedef ElfW(Ehdr) Elf_Ehdr; 697 char *base = (char *)map->l_addr; 698 Elf_Ehdr *ehdr = (Elf_Ehdr *)base; 699 char *phdrs = base + ehdr->e_phoff; 700 char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize; 701 702 // Find the segment with the minimum base so we can "relocate" the p_vaddr 703 // fields. Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC 704 // objects have a non-zero base. 705 uptr preferred_base = (uptr)-1; 706 for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) { 707 Elf_Phdr *phdr = (Elf_Phdr *)iter; 708 if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr) 709 preferred_base = (uptr)phdr->p_vaddr; 710 } 711 712 // Compute the delta from the real base to get a relocation delta. 713 sptr delta = (uptr)base - preferred_base; 714 // Now we can figure out what the loader really mapped. 715 for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) { 716 Elf_Phdr *phdr = (Elf_Phdr *)iter; 717 if (phdr->p_type == PT_LOAD) { 718 uptr seg_start = phdr->p_vaddr + delta; 719 uptr seg_end = seg_start + phdr->p_memsz; 720 // None of these values are aligned. We consider the ragged edges of the 721 // load command as defined, since they are mapped from the file. 722 seg_start = RoundDownTo(seg_start, GetPageSizeCached()); 723 seg_end = RoundUpTo(seg_end, GetPageSizeCached()); 724 cb((void *)seg_start, seg_end - seg_start); 725 } 726 } 727} 728#endif 729 730#if defined(__x86_64__) 731// We cannot use glibc's clone wrapper, because it messes with the child 732// task's TLS. It writes the PID and TID of the child task to its thread 733// descriptor, but in our case the child task shares the thread descriptor with 734// the parent (because we don't know how to allocate a new thread 735// descriptor to keep glibc happy). So the stock version of clone(), when 736// used with CLONE_VM, would end up corrupting the parent's thread descriptor. 737uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg, 738 int *parent_tidptr, void *newtls, int *child_tidptr) { 739 long long res; 740 if (!fn || !child_stack) 741 return -EINVAL; 742 CHECK_EQ(0, (uptr)child_stack % 16); 743 child_stack = (char *)child_stack - 2 * sizeof(void *); 744 ((void **)child_stack)[0] = (void *)(uptr)fn; 745 ((void **)child_stack)[1] = arg; 746 __asm__ __volatile__( 747 /* %rax = syscall(%rax = __NR_clone, 748 * %rdi = flags, 749 * %rsi = child_stack, 750 * %rdx = parent_tidptr, 751 * %r8 = new_tls, 752 * %r10 = child_tidptr) 753 */ 754 "movq %6,%%r8\n" 755 "movq %7,%%r10\n" 756 ".cfi_endproc\n" 757 "syscall\n" 758 759 /* if (%rax != 0) 760 * return; 761 */ 762 "testq %%rax,%%rax\n" 763 "jnz 1f\n" 764 765 /* In the child. Terminate unwind chain. */ 766 ".cfi_startproc\n" 767 ".cfi_undefined %%rip;\n" 768 "xorq %%rbp,%%rbp\n" 769 770 /* Call "fn(arg)". */ 771 "popq %%rax\n" 772 "popq %%rdi\n" 773 "call *%%rax\n" 774 775 /* Call _exit(%rax). */ 776 "movq %%rax,%%rdi\n" 777 "movq %2,%%rax\n" 778 "syscall\n" 779 780 /* Return to parent. */ 781 "1:\n" 782 : "=a" (res) 783 : "a"(__NR_clone), "i"(__NR_exit), 784 "S"(child_stack), 785 "D"(flags), 786 "d"(parent_tidptr), 787 "r"(newtls), 788 "r"(child_tidptr) 789 : "rsp", "memory", "r8", "r10", "r11", "rcx"); 790 return res; 791} 792#endif // defined(__x86_64__) 793} // namespace __sanitizer 794 795#endif // SANITIZER_LINUX 796