libsanitizer/sanitizer_common/sanitizer_linux.cc

   1 //===-- sanitizer_linux.cc ------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is shared between AddressSanitizer and ThreadSanitizer
   9 // run-time libraries and implements linux-specific functions from
  10 // sanitizer_libc.h.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_platform.h"
  14
  15 #if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD
  16
  17 #include "sanitizer_common.h"
  18 #include "sanitizer_flags.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 #if SANITIZER_LINUX
  29 #include <asm/param.h>
  30 #endif
  31
  32 #if SANITIZER_NETBSD
  33 #include <lwp.h>
  34 #endif
  35
  36 // For mips64, syscall(__NR_stat) fills the buffer in the 'struct kernel_stat'
  37 // format. Struct kernel_stat is defined as 'struct stat' in asm/stat.h. To
  38 // access stat from asm/stat.h, without conflicting with definition in
  39 // sys/stat.h, we use this trick.
  40 #if defined(__mips64)
  41 #include <asm/unistd.h>
  42 #include <sys/types.h>
  43 #define stat kernel_stat
  44 #include <asm/stat.h>
  45 #undef stat
  46 #endif
  47
  48 #include <dlfcn.h>
  49 #include <errno.h>
  50 #include <fcntl.h>
  51 #include <link.h>
  52 #include <pthread.h>
  53 #include <sched.h>
  54 #include <sys/mman.h>
  55 #include <sys/ptrace.h>
  56 #include <sys/resource.h>
  57 #include <sys/stat.h>
  58 #include <sys/syscall.h>
  59 #include <sys/time.h>
  60 #include <sys/types.h>
  61 #include <ucontext.h>
  62 #include <unistd.h>
  63
  64 #if SANITIZER_LINUX
  65 #include <sys/utsname.h>
  66 #endif
  67
  68 #if SANITIZER_LINUX && !SANITIZER_ANDROID
  69 #include <sys/personality.h>
  70 #endif
  71
  72 #if SANITIZER_FREEBSD
  73 #include <sys/exec.h>
  74 #include <sys/sysctl.h>
  75 #include <machine/atomic.h>
  76 extern "C" {
  77 // <sys/umtx.h> must be included after <errno.h> and <sys/types.h> on
  78 // FreeBSD 9.2 and 10.0.
  79 #include <sys/umtx.h>
  80 }
  81 extern char **environ;  // provided by crt1
  82 #endif  // SANITIZER_FREEBSD
  83
  84 #if SANITIZER_NETBSD
  85 #include <limits.h>  // For NAME_MAX
  86 #include <sys/sysctl.h>
  87 extern char **environ;  // provided by crt1
  88 #endif                  // SANITIZER_NETBSD
  89
  90 #if !SANITIZER_ANDROID
  91 #include <sys/signal.h>
  92 #endif
  93
  94 #ifndef __GLIBC_PREREQ
  95 #define __GLIBC_PREREQ(x, y) 0
  96 #endif
  97
  98 #if SANITIZER_LINUX && __GLIBC_PREREQ(2, 16)
  99 # define SANITIZER_USE_GETAUXVAL 1
 100 #else
 101 # define SANITIZER_USE_GETAUXVAL 0
 102 #endif
 103
 104 #if SANITIZER_USE_GETAUXVAL
 105 #include <sys/auxv.h>
 106 #endif
 107
 108 #if SANITIZER_LINUX
 109 // <linux/time.h>
 110 struct kernel_timeval {
 111   long tv_sec;
 112   long tv_usec;
 113 };
 114
 115 // <linux/futex.h> is broken on some linux distributions.
 116 const int FUTEX_WAIT = 0;
 117 const int FUTEX_WAKE = 1;
 118 #endif  // SANITIZER_LINUX
 119
 120 // Are we using 32-bit or 64-bit Linux syscalls?
 121 // x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 32
 122 // but it still needs to use 64-bit syscalls.
 123 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__powerpc64__) || \
 124     SANITIZER_WORDSIZE == 64)
 125 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 1
 126 #else
 127 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 0
 128 #endif
 129
 130 #if defined(__x86_64__) || SANITIZER_MIPS64
 131 extern "C" {
 132 extern void internal_sigreturn();
 133 }
 134 #endif
 135
 136 #if SANITIZER_LINUX && defined(__NR_getrandom)
 137 # if !defined(GRND_NONBLOCK)
 138 #  define GRND_NONBLOCK 1
 139 # endif
 140 # define SANITIZER_USE_GETRANDOM 1
 141 #else
 142 # define SANITIZER_USE_GETRANDOM 0
 143 #endif  // SANITIZER_LINUX && defined(__NR_getrandom)
 144
 145 namespace __sanitizer {
 146
 147 #if SANITIZER_LINUX && defined(__x86_64__)
 148 #include "sanitizer_syscall_linux_x86_64.inc"
 149 #elif SANITIZER_LINUX && defined(__aarch64__)
 150 #include "sanitizer_syscall_linux_aarch64.inc"
 151 #else
 152 #include "sanitizer_syscall_generic.inc"
 153 #endif
 154
 155 // --------------- sanitizer_libc.h
 156 #if !SANITIZER_S390
 157 uptr internal_mmap(void *addr, uptr length, int prot, int flags, int fd,
 158                    OFF_T offset) {
 159 #if SANITIZER_NETBSD
 160   return internal_syscall_ptr(SYSCALL(mmap), addr, length, prot, flags, fd,
 161                               (long)0, offset);
 162 #elif SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
 163   return internal_syscall(SYSCALL(mmap), (uptr)addr, length, prot, flags, fd,
 164                           offset);
 165 #else
 166   // mmap2 specifies file offset in 4096-byte units.
 167   CHECK(IsAligned(offset, 4096));
 168   return internal_syscall(SYSCALL(mmap2), addr, length, prot, flags, fd,
 169                           offset / 4096);
 170 #endif
 171 }
 172 #endif // !SANITIZER_S390
 173
 174 uptr internal_munmap(void *addr, uptr length) {
 175   return internal_syscall(SYSCALL(munmap), (uptr)addr, length);
 176 }
 177
 178 int internal_mprotect(void *addr, uptr length, int prot) {
 179   return internal_syscall(SYSCALL(mprotect), (uptr)addr, length, prot);
 180 }
 181
 182 uptr internal_close(fd_t fd) {
 183   return internal_syscall(SYSCALL(close), fd);
 184 }
 185
 186 uptr internal_open(const char *filename, int flags) {
 187 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 188   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags);
 189 #else
 190   return internal_syscall(SYSCALL(open), (uptr)filename, flags);
 191 #endif
 192 }
 193
 194 uptr internal_open(const char *filename, int flags, u32 mode) {
 195 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 196   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags,
 197                           mode);
 198 #else
 199   return internal_syscall(SYSCALL(open), (uptr)filename, flags, mode);
 200 #endif
 201 }
 202
 203 uptr internal_read(fd_t fd, void *buf, uptr count) {
 204   sptr res;
 205 #if SANITIZER_NETBSD
 206   HANDLE_EINTR(res, internal_syscall_ptr(SYSCALL(read), fd, buf, count));
 207 #else
 208   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(read), fd, (uptr)buf,
 209                count));
 210 #endif
 211   return res;
 212 }
 213
 214 uptr internal_write(fd_t fd, const void *buf, uptr count) {
 215   sptr res;
 216 #if SANITIZER_NETBSD
 217   HANDLE_EINTR(res, internal_syscall_ptr(SYSCALL(write), fd, buf, count));
 218 #else
 219   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(write), fd, (uptr)buf,
 220                count));
 221 #endif
 222   return res;
 223 }
 224
 225 uptr internal_ftruncate(fd_t fd, uptr size) {
 226   sptr res;
 227 #if SANITIZER_NETBSD
 228   HANDLE_EINTR(res, internal_syscall(SYSCALL(ftruncate), fd, 0, (s64)size));
 229 #else
 230   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(ftruncate), fd,
 231                (OFF_T)size));
 232 #endif
 233   return res;
 234 }
 235
 236 #if !SANITIZER_LINUX_USES_64BIT_SYSCALLS && SANITIZER_LINUX
 237 static void stat64_to_stat(struct stat64 *in, struct stat *out) {
 238   internal_memset(out, 0, sizeof(*out));
 239   out->st_dev = in->st_dev;
 240   out->st_ino = in->st_ino;
 241   out->st_mode = in->st_mode;
 242   out->st_nlink = in->st_nlink;
 243   out->st_uid = in->st_uid;
 244   out->st_gid = in->st_gid;
 245   out->st_rdev = in->st_rdev;
 246   out->st_size = in->st_size;
 247   out->st_blksize = in->st_blksize;
 248   out->st_blocks = in->st_blocks;
 249   out->st_atime = in->st_atime;
 250   out->st_mtime = in->st_mtime;
 251   out->st_ctime = in->st_ctime;
 252 }
 253 #endif
 254
 255 #if defined(__mips64)
 256 // Undefine compatibility macros from <sys/stat.h>
 257 // so that they would not clash with the kernel_stat
 258 // st_[a|m|c]time fields
 259 #undef st_atime
 260 #undef st_mtime
 261 #undef st_ctime
 262 #if defined(SANITIZER_ANDROID)
 263 // Bionic sys/stat.h defines additional macros
 264 // for compatibility with the old NDKs and
 265 // they clash with the kernel_stat structure
 266 // st_[a|m|c]time_nsec fields.
 267 #undef st_atime_nsec
 268 #undef st_mtime_nsec
 269 #undef st_ctime_nsec
 270 #endif
 271 static void kernel_stat_to_stat(struct kernel_stat *in, struct stat *out) {
 272   internal_memset(out, 0, sizeof(*out));
 273   out->st_dev = in->st_dev;
 274   out->st_ino = in->st_ino;
 275   out->st_mode = in->st_mode;
 276   out->st_nlink = in->st_nlink;
 277   out->st_uid = in->st_uid;
 278   out->st_gid = in->st_gid;
 279   out->st_rdev = in->st_rdev;
 280   out->st_size = in->st_size;
 281   out->st_blksize = in->st_blksize;
 282   out->st_blocks = in->st_blocks;
 283 #if defined(__USE_MISC)     || \
 284     defined(__USE_XOPEN2K8) || \
 285     defined(SANITIZER_ANDROID)
 286   out->st_atim.tv_sec = in->st_atime;
 287   out->st_atim.tv_nsec = in->st_atime_nsec;
 288   out->st_mtim.tv_sec = in->st_mtime;
 289   out->st_mtim.tv_nsec = in->st_mtime_nsec;
 290   out->st_ctim.tv_sec = in->st_ctime;
 291   out->st_ctim.tv_nsec = in->st_ctime_nsec;
 292 #else
 293   out->st_atime = in->st_atime;
 294   out->st_atimensec = in->st_atime_nsec;
 295   out->st_mtime = in->st_mtime;
 296   out->st_mtimensec = in->st_mtime_nsec;
 297   out->st_ctime = in->st_ctime;
 298   out->st_atimensec = in->st_ctime_nsec;
 299 #endif
 300 }
 301 #endif
 302
 303 uptr internal_stat(const char *path, void *buf) {
 304 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
 305   return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path,
 306                           (uptr)buf, 0);
 307 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 308   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path,
 309                           (uptr)buf, 0);
 310 #elif SANITIZER_LINUX_USES_64BIT_SYSCALLS
 311 # if defined(__mips64)
 312   // For mips64, stat syscall fills buffer in the format of kernel_stat
 313   struct kernel_stat kbuf;
 314   int res = internal_syscall(SYSCALL(stat), path, &kbuf);
 315   kernel_stat_to_stat(&kbuf, (struct stat *)buf);
 316   return res;
 317 # else
 318   return internal_syscall(SYSCALL(stat), (uptr)path, (uptr)buf);
 319 # endif
 320 #else
 321   struct stat64 buf64;
 322   int res = internal_syscall(SYSCALL(stat64), path, &buf64);
 323   stat64_to_stat(&buf64, (struct stat *)buf);
 324   return res;
 325 #endif
 326 }
 327
 328 uptr internal_lstat(const char *path, void *buf) {
 329 #if SANITIZER_NETBSD
 330   return internal_syscall(SYSCALL(lstat), path, buf);
 331 #elif SANITIZER_FREEBSD
 332   return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path,
 333                           (uptr)buf, AT_SYMLINK_NOFOLLOW);
 334 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 335   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path,
 336                          (uptr)buf, AT_SYMLINK_NOFOLLOW);
 337 #elif SANITIZER_LINUX_USES_64BIT_SYSCALLS
 338 # if SANITIZER_MIPS64
 339   // For mips64, lstat syscall fills buffer in the format of kernel_stat
 340   struct kernel_stat kbuf;
 341   int res = internal_syscall(SYSCALL(lstat), path, &kbuf);
 342   kernel_stat_to_stat(&kbuf, (struct stat *)buf);
 343   return res;
 344 # else
 345   return internal_syscall(SYSCALL(lstat), (uptr)path, (uptr)buf);
 346 # endif
 347 #else
 348   struct stat64 buf64;
 349   int res = internal_syscall(SYSCALL(lstat64), path, &buf64);
 350   stat64_to_stat(&buf64, (struct stat *)buf);
 351   return res;
 352 #endif
 353 }
 354
 355 uptr internal_fstat(fd_t fd, void *buf) {
 356 #if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS || SANITIZER_NETBSD
 357 # if SANITIZER_MIPS64
 358   // For mips64, fstat syscall fills buffer in the format of kernel_stat
 359   struct kernel_stat kbuf;
 360   int res = internal_syscall(SYSCALL(fstat), fd, &kbuf);
 361   kernel_stat_to_stat(&kbuf, (struct stat *)buf);
 362   return res;
 363 # else
 364   return internal_syscall(SYSCALL(fstat), fd, (uptr)buf);
 365 # endif
 366 #else
 367   struct stat64 buf64;
 368   int res = internal_syscall(SYSCALL(fstat64), fd, &buf64);
 369   stat64_to_stat(&buf64, (struct stat *)buf);
 370   return res;
 371 #endif
 372 }
 373
 374 uptr internal_filesize(fd_t fd) {
 375   struct stat st;
 376   if (internal_fstat(fd, &st))
 377     return -1;
 378   return (uptr)st.st_size;
 379 }
 380
 381 uptr internal_dup2(int oldfd, int newfd) {
 382 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 383   return internal_syscall(SYSCALL(dup3), oldfd, newfd, 0);
 384 #else
 385   return internal_syscall(SYSCALL(dup2), oldfd, newfd);
 386 #endif
 387 }
 388
 389 uptr internal_readlink(const char *path, char *buf, uptr bufsize) {
 390 #if SANITIZER_NETBSD
 391   return internal_syscall_ptr(SYSCALL(readlink), path, buf, bufsize);
 392 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 393   return internal_syscall(SYSCALL(readlinkat), AT_FDCWD,
 394                           (uptr)path, (uptr)buf, bufsize);
 395 #else
 396   return internal_syscall(SYSCALL(readlink), (uptr)path, (uptr)buf, bufsize);
 397 #endif
 398 }
 399
 400 uptr internal_unlink(const char *path) {
 401 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 402   return internal_syscall(SYSCALL(unlinkat), AT_FDCWD, (uptr)path, 0);
 403 #else
 404   return internal_syscall(SYSCALL(unlink), (uptr)path);
 405 #endif
 406 }
 407
 408 uptr internal_rename(const char *oldpath, const char *newpath) {
 409 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 410   return internal_syscall(SYSCALL(renameat), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
 411                           (uptr)newpath);
 412 #else
 413   return internal_syscall(SYSCALL(rename), (uptr)oldpath, (uptr)newpath);
 414 #endif
 415 }
 416
 417 uptr internal_sched_yield() {
 418   return internal_syscall(SYSCALL(sched_yield));
 419 }
 420
 421 void internal__exit(int exitcode) {
 422 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
 423   internal_syscall(SYSCALL(exit), exitcode);
 424 #else
 425   internal_syscall(SYSCALL(exit_group), exitcode);
 426 #endif
 427   Die();  // Unreachable.
 428 }
 429
 430 unsigned int internal_sleep(unsigned int seconds) {
 431   struct timespec ts;
 432   ts.tv_sec = 1;
 433   ts.tv_nsec = 0;
 434   int res = internal_syscall(SYSCALL(nanosleep), &ts, &ts);
 435   if (res) return ts.tv_sec;
 436   return 0;
 437 }
 438
 439 uptr internal_execve(const char *filename, char *const argv[],
 440                      char *const envp[]) {
 441   return internal_syscall(SYSCALL(execve), (uptr)filename, (uptr)argv,
 442                           (uptr)envp);
 443 }
 444
 445 // ----------------- sanitizer_common.h
 446 bool FileExists(const char *filename) {
 447   struct stat st;
 448 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 449   if (internal_syscall(SYSCALL(newfstatat), AT_FDCWD, filename, &st, 0))
 450 #else
 451   if (internal_stat(filename, &st))
 452 #endif
 453     return false;
 454   // Sanity check: filename is a regular file.
 455   return S_ISREG(st.st_mode);
 456 }
 457
 458 tid_t GetTid() {
 459 #if SANITIZER_FREEBSD
 460   return (uptr)pthread_self();
 461 #elif SANITIZER_NETBSD
 462   return _lwp_self();
 463 #else
 464   return internal_syscall(SYSCALL(gettid));
 465 #endif
 466 }
 467
 468 u64 NanoTime() {
 469 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
 470   timeval tv;
 471 #else
 472   kernel_timeval tv;
 473 #endif
 474   internal_memset(&tv, 0, sizeof(tv));
 475 #if SANITIZER_NETBSD
 476   internal_syscall_ptr(SYSCALL(gettimeofday), &tv, NULL);
 477 #else
 478   internal_syscall(SYSCALL(gettimeofday), (uptr)&tv, 0);
 479 #endif
 480   return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000;
 481 }
 482
 483 // Like getenv, but reads env directly from /proc (on Linux) or parses the
 484 // 'environ' array (on FreeBSD) and does not use libc. This function should be
 485 // called first inside __asan_init.
 486 const char *GetEnv(const char *name) {
 487 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
 488   if (::environ != 0) {
 489     uptr NameLen = internal_strlen(name);
 490     for (char **Env = ::environ; *Env != 0; Env++) {
 491       if (internal_strncmp(*Env, name, NameLen) == 0 && (*Env)[NameLen] == '=')
 492         return (*Env) + NameLen + 1;
 493     }
 494   }
 495   return 0;  // Not found.
 496 #elif SANITIZER_LINUX
 497   static char *environ;
 498   static uptr len;
 499   static bool inited;
 500   if (!inited) {
 501     inited = true;
 502     uptr environ_size;
 503     if (!ReadFileToBuffer("/proc/self/environ", &environ, &environ_size, &len))
 504       environ = nullptr;
 505   }
 506   if (!environ || len == 0) return nullptr;
 507   uptr namelen = internal_strlen(name);
 508   const char *p = environ;
 509   while (*p != '\0') {  // will happen at the \0\0 that terminates the buffer
 510     // proc file has the format NAME=value\0NAME=value\0NAME=value\0...
 511     const char* endp =
 512         (char*)internal_memchr(p, '\0', len - (p - environ));
 513     if (!endp)  // this entry isn't NUL terminated
 514       return nullptr;
 515     else if (!internal_memcmp(p, name, namelen) && p[namelen] == '=')  // Match.
 516       return p + namelen + 1;  // point after =
 517     p = endp + 1;
 518   }
 519   return nullptr;  // Not found.
 520 #else
 521 #error "Unsupported platform"
 522 #endif
 523 }
 524
 525 #if !SANITIZER_FREEBSD
 526 extern "C" {
 527   SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end;
 528 }
 529 #endif
 530
 531 #if !SANITIZER_GO && !SANITIZER_FREEBSD
 532 static void ReadNullSepFileToArray(const char *path, char ***arr,
 533                                    int arr_size) {
 534   char *buff;
 535   uptr buff_size;
 536   uptr buff_len;
 537   *arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray");
 538   if (!ReadFileToBuffer(path, &buff, &buff_size, &buff_len, 1024 * 1024)) {
 539     (*arr)[0] = nullptr;
 540     return;
 541   }
 542   (*arr)[0] = buff;
 543   int count, i;
 544   for (count = 1, i = 1; ; i++) {
 545     if (buff[i] == 0) {
 546       if (buff[i+1] == 0) break;
 547       (*arr)[count] = &buff[i+1];
 548       CHECK_LE(count, arr_size - 1);  // FIXME: make this more flexible.
 549       count++;
 550     }
 551   }
 552   (*arr)[count] = nullptr;
 553 }
 554 #endif
 555
 556 static void GetArgsAndEnv(char ***argv, char ***envp) {
 557 #if !SANITIZER_FREEBSD
 558 #if !SANITIZER_GO
 559   if (&__libc_stack_end) {
 560 #endif
 561     uptr* stack_end = (uptr*)__libc_stack_end;
 562     int argc = *stack_end;
 563     *argv = (char**)(stack_end + 1);
 564     *envp = (char**)(stack_end + argc + 2);
 565 #if !SANITIZER_GO
 566   } else {
 567     static const int kMaxArgv = 2000, kMaxEnvp = 2000;
 568     ReadNullSepFileToArray("/proc/self/cmdline", argv, kMaxArgv);
 569     ReadNullSepFileToArray("/proc/self/environ", envp, kMaxEnvp);
 570   }
 571 #endif
 572 #else
 573   // On FreeBSD, retrieving the argument and environment arrays is done via the
 574   // kern.ps_strings sysctl, which returns a pointer to a structure containing
 575   // this information. See also <sys/exec.h>.
 576   ps_strings *pss;
 577   size_t sz = sizeof(pss);
 578   if (sysctlbyname("kern.ps_strings", &pss, &sz, NULL, 0) == -1) {
 579     Printf("sysctl kern.ps_strings failed\n");
 580     Die();
 581   }
 582   *argv = pss->ps_argvstr;
 583   *envp = pss->ps_envstr;
 584 #endif
 585 }
 586
 587 char **GetArgv() {
 588   char **argv, **envp;
 589   GetArgsAndEnv(&argv, &envp);
 590   return argv;
 591 }
 592
 593 void ReExec() {
 594   char **argv, **envp;
 595   GetArgsAndEnv(&argv, &envp);
 596   uptr rv = internal_execve("/proc/self/exe", argv, envp);
 597   int rverrno;
 598   CHECK_EQ(internal_iserror(rv, &rverrno), true);
 599   Printf("execve failed, errno %d\n", rverrno);
 600   Die();
 601 }
 602
 603 enum MutexState {
 604   MtxUnlocked = 0,
 605   MtxLocked = 1,
 606   MtxSleeping = 2
 607 };
 608
 609 BlockingMutex::BlockingMutex() {
 610   internal_memset(this, 0, sizeof(*this));
 611 }
 612
 613 void BlockingMutex::Lock() {
 614   CHECK_EQ(owner_, 0);
 615   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
 616   if (atomic_exchange(m, MtxLocked, memory_order_acquire) == MtxUnlocked)
 617     return;
 618   while (atomic_exchange(m, MtxSleeping, memory_order_acquire) != MtxUnlocked) {
 619 #if SANITIZER_FREEBSD
 620     _umtx_op(m, UMTX_OP_WAIT_UINT, MtxSleeping, 0, 0);
 621 #elif SANITIZER_NETBSD
 622     sched_yield(); /* No userspace futex-like synchromization */
 623 #else
 624     internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAIT, MtxSleeping, 0, 0, 0);
 625 #endif
 626   }
 627 }
 628
 629 void BlockingMutex::Unlock() {
 630   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
 631   u32 v = atomic_exchange(m, MtxUnlocked, memory_order_release);
 632   CHECK_NE(v, MtxUnlocked);
 633   if (v == MtxSleeping) {
 634 #if SANITIZER_FREEBSD
 635     _umtx_op(m, UMTX_OP_WAKE, 1, 0, 0);
 636 #elif SANITIZER_NETBSD
 637                    /* No userspace futex-like synchromization */
 638 #else
 639     internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAKE, 1, 0, 0, 0);
 640 #endif
 641   }
 642 }
 643
 644 void BlockingMutex::CheckLocked() {
 645   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
 646   CHECK_NE(MtxUnlocked, atomic_load(m, memory_order_relaxed));
 647 }
 648
 649 // ----------------- sanitizer_linux.h
 650 // The actual size of this structure is specified by d_reclen.
 651 // Note that getdents64 uses a different structure format. We only provide the
 652 // 32-bit syscall here.
 653 #if SANITIZER_NETBSD
 654 // struct dirent is different for Linux and us. At this moment, we use only
 655 // d_fileno (Linux call this d_ino), d_reclen, and d_name.
 656 struct linux_dirent {
 657   u64 d_ino;  // d_fileno
 658   u16 d_reclen;
 659   u16 d_namlen;  // not used
 660   u8 d_type;     // not used
 661   char d_name[NAME_MAX + 1];
 662 };
 663 #else
 664 struct linux_dirent {
 665 #if SANITIZER_X32 || defined(__aarch64__)
 666   u64 d_ino;
 667   u64 d_off;
 668 #else
 669   unsigned long      d_ino;
 670   unsigned long      d_off;
 671 #endif
 672   unsigned short     d_reclen;
 673 #ifdef __aarch64__
 674   unsigned char      d_type;
 675 #endif
 676   char               d_name[256];
 677 };
 678 #endif
 679
 680 // Syscall wrappers.
 681 uptr internal_ptrace(int request, int pid, void *addr, void *data) {
 682 #if SANITIZER_NETBSD
 683   // XXX We need additional work for ptrace:
 684   //   - for request, we use PT_FOO whereas Linux uses PTRACE_FOO
 685   //   - data is int for us, but void * for Linux
 686   //   - Linux sometimes uses data in the case where we use addr instead
 687   // At this moment, this function is used only within
 688   // "#if SANITIZER_LINUX && defined(__x86_64__)" block in
 689   // sanitizer_stoptheworld_linux_libcdep.cc.
 690   return internal_syscall_ptr(SYSCALL(ptrace), request, pid, (uptr)addr,
 691                               (uptr)data);
 692 #else
 693   return internal_syscall(SYSCALL(ptrace), request, pid, (uptr)addr,
 694                           (uptr)data);
 695 #endif
 696 }
 697
 698 uptr internal_waitpid(int pid, int *status, int options) {
 699 #if SANITIZER_NETBSD
 700   return internal_syscall(SYSCALL(wait4), pid, status, options,
 701                           NULL /* rusage */);
 702 #else
 703   return internal_syscall(SYSCALL(wait4), pid, (uptr)status, options,
 704                           0 /* rusage */);
 705 #endif
 706 }
 707
 708 uptr internal_getpid() {
 709   return internal_syscall(SYSCALL(getpid));
 710 }
 711
 712 uptr internal_getppid() {
 713   return internal_syscall(SYSCALL(getppid));
 714 }
 715
 716 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) {
 717 #if SANITIZER_NETBSD
 718   return internal_syscall(SYSCALL(getdents), fd, dirp, (uptr)count);
 719 #elif SANITIZER_FREEBSD
 720   return internal_syscall(SYSCALL(getdirentries), fd, (uptr)dirp, count, NULL);
 721 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 722   return internal_syscall(SYSCALL(getdents64), fd, (uptr)dirp, count);
 723 #else
 724   return internal_syscall(SYSCALL(getdents), fd, (uptr)dirp, count);
 725 #endif
 726 }
 727
 728 uptr internal_lseek(fd_t fd, OFF_T offset, int whence) {
 729 #if SANITIZER_NETBSD
 730   return internal_syscall64(SYSCALL(lseek), fd, 0, offset, whence);
 731 #else
 732   return internal_syscall(SYSCALL(lseek), fd, offset, whence);
 733 #endif
 734 }
 735
 736 #if SANITIZER_LINUX
 737 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) {
 738   return internal_syscall(SYSCALL(prctl), option, arg2, arg3, arg4, arg5);
 739 }
 740 #endif
 741
 742 uptr internal_sigaltstack(const void *ss, void *oss) {
 743   return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
 744 }
 745
 746 int internal_fork() {
 747 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 748   return internal_syscall(SYSCALL(clone), SIGCHLD, 0);
 749 #else
 750   return internal_syscall(SYSCALL(fork));
 751 #endif
 752 }
 753
 754 #if SANITIZER_LINUX
 755 #define SA_RESTORER 0x04000000
 756 // Doesn't set sa_restorer if the caller did not set it, so use with caution
 757 //(see below).
 758 int internal_sigaction_norestorer(int signum, const void *act, void *oldact) {
 759   __sanitizer_kernel_sigaction_t k_act, k_oldact;
 760   internal_memset(&k_act, 0, sizeof(__sanitizer_kernel_sigaction_t));
 761   internal_memset(&k_oldact, 0, sizeof(__sanitizer_kernel_sigaction_t));
 762   const __sanitizer_sigaction *u_act = (const __sanitizer_sigaction *)act;
 763   __sanitizer_sigaction *u_oldact = (__sanitizer_sigaction *)oldact;
 764   if (u_act) {
 765     k_act.handler = u_act->handler;
 766     k_act.sigaction = u_act->sigaction;
 767     internal_memcpy(&k_act.sa_mask, &u_act->sa_mask,
 768                     sizeof(__sanitizer_kernel_sigset_t));
 769     // Without SA_RESTORER kernel ignores the calls (probably returns EINVAL).
 770     k_act.sa_flags = u_act->sa_flags | SA_RESTORER;
 771     // FIXME: most often sa_restorer is unset, however the kernel requires it
 772     // to point to a valid signal restorer that calls the rt_sigreturn syscall.
 773     // If sa_restorer passed to the kernel is NULL, the program may crash upon
 774     // signal delivery or fail to unwind the stack in the signal handler.
 775     // libc implementation of sigaction() passes its own restorer to
 776     // rt_sigaction, so we need to do the same (we'll need to reimplement the
 777     // restorers; for x86_64 the restorer address can be obtained from
 778     // oldact->sa_restorer upon a call to sigaction(xxx, NULL, oldact).
 779 #if !SANITIZER_ANDROID || !SANITIZER_MIPS32
 780     k_act.sa_restorer = u_act->sa_restorer;
 781 #endif
 782   }
 783
 784   uptr result = internal_syscall(SYSCALL(rt_sigaction), (uptr)signum,
 785       (uptr)(u_act ? &k_act : nullptr),
 786       (uptr)(u_oldact ? &k_oldact : nullptr),
 787       (uptr)sizeof(__sanitizer_kernel_sigset_t));
 788
 789   if ((result == 0) && u_oldact) {
 790     u_oldact->handler = k_oldact.handler;
 791     u_oldact->sigaction = k_oldact.sigaction;
 792     internal_memcpy(&u_oldact->sa_mask, &k_oldact.sa_mask,
 793                     sizeof(__sanitizer_kernel_sigset_t));
 794     u_oldact->sa_flags = k_oldact.sa_flags;
 795 #if !SANITIZER_ANDROID || !SANITIZER_MIPS32
 796     u_oldact->sa_restorer = k_oldact.sa_restorer;
 797 #endif
 798   }
 799   return result;
 800 }
 801
 802 // Invokes sigaction via a raw syscall with a restorer, but does not support
 803 // all platforms yet.
 804 // We disable for Go simply because we have not yet added to buildgo.sh.
 805 #if (defined(__x86_64__) || SANITIZER_MIPS64) && !SANITIZER_GO
 806 int internal_sigaction_syscall(int signum, const void *act, void *oldact) {
 807   if (act == nullptr)
 808     return internal_sigaction_norestorer(signum, act, oldact);
 809   __sanitizer_sigaction u_adjust;
 810   internal_memcpy(&u_adjust, act, sizeof(u_adjust));
 811 #if !SANITIZER_ANDROID || !SANITIZER_MIPS32
 812     if (u_adjust.sa_restorer == nullptr) {
 813       u_adjust.sa_restorer = internal_sigreturn;
 814     }
 815 #endif
 816     return internal_sigaction_norestorer(signum, (const void *)&u_adjust,
 817                                          oldact);
 818 }
 819 #endif // defined(__x86_64__) && !SANITIZER_GO
 820 #endif  // SANITIZER_LINUX
 821
 822 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
 823     __sanitizer_sigset_t *oldset) {
 824 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
 825   return internal_syscall(SYSCALL(sigprocmask), how, set, oldset);
 826 #else
 827   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
 828   __sanitizer_kernel_sigset_t *k_oldset = (__sanitizer_kernel_sigset_t *)oldset;
 829   return internal_syscall(SYSCALL(rt_sigprocmask), (uptr)how,
 830                           (uptr)&k_set->sig[0], (uptr)&k_oldset->sig[0],
 831                           sizeof(__sanitizer_kernel_sigset_t));
 832 #endif
 833 }
 834
 835 void internal_sigfillset(__sanitizer_sigset_t *set) {
 836   internal_memset(set, 0xff, sizeof(*set));
 837 }
 838
 839 void internal_sigemptyset(__sanitizer_sigset_t *set) {
 840   internal_memset(set, 0, sizeof(*set));
 841 }
 842
 843 #if SANITIZER_LINUX
 844 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
 845   signum -= 1;
 846   CHECK_GE(signum, 0);
 847   CHECK_LT(signum, sizeof(*set) * 8);
 848   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
 849   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
 850   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
 851   k_set->sig[idx] &= ~(1 << bit);
 852 }
 853
 854 bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
 855   signum -= 1;
 856   CHECK_GE(signum, 0);
 857   CHECK_LT(signum, sizeof(*set) * 8);
 858   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
 859   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
 860   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
 861   return k_set->sig[idx] & (1 << bit);
 862 }
 863 #endif  // SANITIZER_LINUX
 864
 865 // ThreadLister implementation.
 866 ThreadLister::ThreadLister(int pid)
 867   : pid_(pid),
 868     descriptor_(-1),
 869     buffer_(4096),
 870     error_(true),
 871     entry_((struct linux_dirent *)buffer_.data()),
 872     bytes_read_(0) {
 873   char task_directory_path[80];
 874   internal_snprintf(task_directory_path, sizeof(task_directory_path),
 875                     "/proc/%d/task/", pid);
 876   uptr openrv = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY);
 877   if (internal_iserror(openrv)) {
 878     error_ = true;
 879     Report("Can't open /proc/%d/task for reading.\n", pid);
 880   } else {
 881     error_ = false;
 882     descriptor_ = openrv;
 883   }
 884 }
 885
 886 int ThreadLister::GetNextTID() {
 887   int tid = -1;
 888   do {
 889     if (error_)
 890       return -1;
 891     if ((char *)entry_ >= &buffer_[bytes_read_] && !GetDirectoryEntries())
 892       return -1;
 893     if (entry_->d_ino != 0 && entry_->d_name[0] >= '0' &&
 894         entry_->d_name[0] <= '9') {
 895       // Found a valid tid.
 896       tid = (int)internal_atoll(entry_->d_name);
 897     }
 898     entry_ = (struct linux_dirent *)(((char *)entry_) + entry_->d_reclen);
 899   } while (tid < 0);
 900   return tid;
 901 }
 902
 903 void ThreadLister::Reset() {
 904   if (error_ || descriptor_ < 0)
 905     return;
 906   internal_lseek(descriptor_, 0, SEEK_SET);
 907 }
 908
 909 ThreadLister::~ThreadLister() {
 910   if (descriptor_ >= 0)
 911     internal_close(descriptor_);
 912 }
 913
 914 bool ThreadLister::error() { return error_; }
 915
 916 bool ThreadLister::GetDirectoryEntries() {
 917   CHECK_GE(descriptor_, 0);
 918   CHECK_NE(error_, true);
 919   bytes_read_ = internal_getdents(descriptor_,
 920                                   (struct linux_dirent *)buffer_.data(),
 921                                   buffer_.size());
 922   if (internal_iserror(bytes_read_)) {
 923     Report("Can't read directory entries from /proc/%d/task.\n", pid_);
 924     error_ = true;
 925     return false;
 926   } else if (bytes_read_ == 0) {
 927     return false;
 928   }
 929   entry_ = (struct linux_dirent *)buffer_.data();
 930   return true;
 931 }
 932
 933 #if SANITIZER_WORDSIZE == 32
 934 // Take care of unusable kernel area in top gigabyte.
 935 static uptr GetKernelAreaSize() {
 936 #if SANITIZER_LINUX && !SANITIZER_X32
 937   const uptr gbyte = 1UL << 30;
 938
 939   // Firstly check if there are writable segments
 940   // mapped to top gigabyte (e.g. stack).
 941   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 942   MemoryMappedSegment segment;
 943   while (proc_maps.Next(&segment)) {
 944     if ((segment.end >= 3 * gbyte) && segment.IsWritable()) return 0;
 945   }
 946
 947 #if !SANITIZER_ANDROID
 948   // Even if nothing is mapped, top Gb may still be accessible
 949   // if we are running on 64-bit kernel.
 950   // Uname may report misleading results if personality type
 951   // is modified (e.g. under schroot) so check this as well.
 952   struct utsname uname_info;
 953   int pers = personality(0xffffffffUL);
 954   if (!(pers & PER_MASK)
 955       && uname(&uname_info) == 0
 956       && internal_strstr(uname_info.machine, "64"))
 957     return 0;
 958 #endif  // SANITIZER_ANDROID
 959
 960   // Top gigabyte is reserved for kernel.
 961   return gbyte;
 962 #else
 963   return 0;
 964 #endif  // SANITIZER_LINUX && !SANITIZER_X32
 965 }
 966 #endif  // SANITIZER_WORDSIZE == 32
 967
 968 uptr GetMaxVirtualAddress() {
 969 #if SANITIZER_NETBSD && defined(__x86_64__)
 970   return 0x7f7ffffff000ULL;  // (0x00007f8000000000 - PAGE_SIZE)
 971 #elif SANITIZER_WORDSIZE == 64
 972 # if defined(__powerpc64__) || defined(__aarch64__)
 973   // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
 974   // We somehow need to figure out which one we are using now and choose
 975   // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
 976   // Note that with 'ulimit -s unlimited' the stack is moved away from the top
 977   // of the address space, so simply checking the stack address is not enough.
 978   // This should (does) work for both PowerPC64 Endian modes.
 979   // Similarly, aarch64 has multiple address space layouts: 39, 42 and 47-bit.
 980   return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
 981 # elif defined(__mips64)
 982   return (1ULL << 40) - 1;  // 0x000000ffffffffffUL;
 983 # elif defined(__s390x__)
 984   return (1ULL << 53) - 1;  // 0x001fffffffffffffUL;
 985 # else
 986   return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
 987 # endif
 988 #else  // SANITIZER_WORDSIZE == 32
 989 # if defined(__s390__)
 990   return (1ULL << 31) - 1;  // 0x7fffffff;
 991 # else
 992   uptr res = (1ULL << 32) - 1;  // 0xffffffff;
 993   if (!common_flags()->full_address_space)
 994     res -= GetKernelAreaSize();
 995   CHECK_LT(reinterpret_cast<uptr>(&res), res);
 996   return res;
 997 # endif
 998 #endif  // SANITIZER_WORDSIZE
 999 }
1000
1001 uptr GetPageSize() {
1002 // Android post-M sysconf(_SC_PAGESIZE) crashes if called from .preinit_array.
1003 #if SANITIZER_ANDROID
1004   return 4096;
1005 #elif SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__))
1006   return EXEC_PAGESIZE;
1007 #elif SANITIZER_USE_GETAUXVAL
1008   return getauxval(AT_PAGESZ);
1009 #else
1010   return sysconf(_SC_PAGESIZE);  // EXEC_PAGESIZE may not be trustworthy.
1011 #endif
1012 }
1013
1014 uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
1015 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
1016 #if SANITIZER_FREEBSD
1017   const int Mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
1018 #else
1019   const int Mib[4] = {CTL_KERN, KERN_PROC_ARGS, -1, KERN_PROC_PATHNAME};
1020 #endif
1021   const char *default_module_name = "kern.proc.pathname";
1022   size_t Size = buf_len;
1023   bool IsErr = (sysctl(Mib, ARRAY_SIZE(Mib), buf, &Size, NULL, 0) != 0);
1024   int readlink_error = IsErr ? errno : 0;
1025   uptr module_name_len = Size;
1026 #else
1027   const char *default_module_name = "/proc/self/exe";
1028   uptr module_name_len = internal_readlink(
1029       default_module_name, buf, buf_len);
1030   int readlink_error;
1031   bool IsErr = internal_iserror(module_name_len, &readlink_error);
1032 #endif
1033   if (IsErr) {
1034     // We can't read binary name for some reason, assume it's unknown.
1035     Report("WARNING: reading executable name failed with errno %d, "
1036            "some stack frames may not be symbolized\n", readlink_error);
1037     module_name_len = internal_snprintf(buf, buf_len, "%s",
1038                                         default_module_name);
1039     CHECK_LT(module_name_len, buf_len);
1040   }
1041   return module_name_len;
1042 }
1043
1044 uptr ReadLongProcessName(/*out*/ char *buf, uptr buf_len) {
1045 #if SANITIZER_LINUX
1046   char *tmpbuf;
1047   uptr tmpsize;
1048   uptr tmplen;
1049   if (ReadFileToBuffer("/proc/self/cmdline", &tmpbuf, &tmpsize, &tmplen,
1050                        1024 * 1024)) {
1051     internal_strncpy(buf, tmpbuf, buf_len);
1052     UnmapOrDie(tmpbuf, tmpsize);
1053     return internal_strlen(buf);
1054   }
1055 #endif
1056   return ReadBinaryName(buf, buf_len);
1057 }
1058
1059 // Match full names of the form /path/to/base_name{-,.}*
1060 bool LibraryNameIs(const char *full_name, const char *base_name) {
1061   const char *name = full_name;
1062   // Strip path.
1063   while (*name != '\0') name++;
1064   while (name > full_name && *name != '/') name--;
1065   if (*name == '/') name++;
1066   uptr base_name_length = internal_strlen(base_name);
1067   if (internal_strncmp(name, base_name, base_name_length)) return false;
1068   return (name[base_name_length] == '-' || name[base_name_length] == '.');
1069 }
1070
1071 #if !SANITIZER_ANDROID
1072 // Call cb for each region mapped by map.
1073 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) {
1074   CHECK_NE(map, nullptr);
1075 #if !SANITIZER_FREEBSD
1076   typedef ElfW(Phdr) Elf_Phdr;
1077   typedef ElfW(Ehdr) Elf_Ehdr;
1078 #endif  // !SANITIZER_FREEBSD
1079   char *base = (char *)map->l_addr;
1080   Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
1081   char *phdrs = base + ehdr->e_phoff;
1082   char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize;
1083
1084   // Find the segment with the minimum base so we can "relocate" the p_vaddr
1085   // fields.  Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC
1086   // objects have a non-zero base.
1087   uptr preferred_base = (uptr)-1;
1088   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
1089     Elf_Phdr *phdr = (Elf_Phdr *)iter;
1090     if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr)
1091       preferred_base = (uptr)phdr->p_vaddr;
1092   }
1093
1094   // Compute the delta from the real base to get a relocation delta.
1095   sptr delta = (uptr)base - preferred_base;
1096   // Now we can figure out what the loader really mapped.
1097   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
1098     Elf_Phdr *phdr = (Elf_Phdr *)iter;
1099     if (phdr->p_type == PT_LOAD) {
1100       uptr seg_start = phdr->p_vaddr + delta;
1101       uptr seg_end = seg_start + phdr->p_memsz;
1102       // None of these values are aligned.  We consider the ragged edges of the
1103       // load command as defined, since they are mapped from the file.
1104       seg_start = RoundDownTo(seg_start, GetPageSizeCached());
1105       seg_end = RoundUpTo(seg_end, GetPageSizeCached());
1106       cb((void *)seg_start, seg_end - seg_start);
1107     }
1108   }
1109 }
1110 #endif
1111
1112 #if defined(__x86_64__) && SANITIZER_LINUX
1113 // We cannot use glibc's clone wrapper, because it messes with the child
1114 // task's TLS. It writes the PID and TID of the child task to its thread
1115 // descriptor, but in our case the child task shares the thread descriptor with
1116 // the parent (because we don't know how to allocate a new thread
1117 // descriptor to keep glibc happy). So the stock version of clone(), when
1118 // used with CLONE_VM, would end up corrupting the parent's thread descriptor.
1119 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1120                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1121   long long res;
1122   if (!fn || !child_stack)
1123     return -EINVAL;
1124   CHECK_EQ(0, (uptr)child_stack % 16);
1125   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1126   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1127   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1128   register void *r8 __asm__("r8") = newtls;
1129   register int *r10 __asm__("r10") = child_tidptr;
1130   __asm__ __volatile__(
1131                        /* %rax = syscall(%rax = SYSCALL(clone),
1132                         *                %rdi = flags,
1133                         *                %rsi = child_stack,
1134                         *                %rdx = parent_tidptr,
1135                         *                %r8  = new_tls,
1136                         *                %r10 = child_tidptr)
1137                         */
1138                        "syscall\n"
1139
1140                        /* if (%rax != 0)
1141                         *   return;
1142                         */
1143                        "testq  %%rax,%%rax\n"
1144                        "jnz    1f\n"
1145
1146                        /* In the child. Terminate unwind chain. */
1147                        // XXX: We should also terminate the CFI unwind chain
1148                        // here. Unfortunately clang 3.2 doesn't support the
1149                        // necessary CFI directives, so we skip that part.
1150                        "xorq   %%rbp,%%rbp\n"
1151
1152                        /* Call "fn(arg)". */
1153                        "popq   %%rax\n"
1154                        "popq   %%rdi\n"
1155                        "call   *%%rax\n"
1156
1157                        /* Call _exit(%rax). */
1158                        "movq   %%rax,%%rdi\n"
1159                        "movq   %2,%%rax\n"
1160                        "syscall\n"
1161
1162                        /* Return to parent. */
1163                      "1:\n"
1164                        : "=a" (res)
1165                        : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
1166                          "S"(child_stack),
1167                          "D"(flags),
1168                          "d"(parent_tidptr),
1169                          "r"(r8),
1170                          "r"(r10)
1171                        : "rsp", "memory", "r11", "rcx");
1172   return res;
1173 }
1174 #elif defined(__mips__)
1175 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1176                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1177   long long res;
1178   if (!fn || !child_stack)
1179     return -EINVAL;
1180   CHECK_EQ(0, (uptr)child_stack % 16);
1181   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1182   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1183   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1184   register void *a3 __asm__("$7") = newtls;
1185   register int *a4 __asm__("$8") = child_tidptr;
1186   // We don't have proper CFI directives here because it requires alot of code
1187   // for very marginal benefits.
1188   __asm__ __volatile__(
1189                        /* $v0 = syscall($v0 = __NR_clone,
1190                         * $a0 = flags,
1191                         * $a1 = child_stack,
1192                         * $a2 = parent_tidptr,
1193                         * $a3 = new_tls,
1194                         * $a4 = child_tidptr)
1195                         */
1196                        ".cprestore 16;\n"
1197                        "move $4,%1;\n"
1198                        "move $5,%2;\n"
1199                        "move $6,%3;\n"
1200                        "move $7,%4;\n"
1201                        /* Store the fifth argument on stack
1202                         * if we are using 32-bit abi.
1203                         */
1204 #if SANITIZER_WORDSIZE == 32
1205                        "lw %5,16($29);\n"
1206 #else
1207                        "move $8,%5;\n"
1208 #endif
1209                        "li $2,%6;\n"
1210                        "syscall;\n"
1211
1212                        /* if ($v0 != 0)
1213                         * return;
1214                         */
1215                        "bnez $2,1f;\n"
1216
1217                        /* Call "fn(arg)". */
1218 #if SANITIZER_WORDSIZE == 32
1219 #ifdef __BIG_ENDIAN__
1220                        "lw $25,4($29);\n"
1221                        "lw $4,12($29);\n"
1222 #else
1223                        "lw $25,0($29);\n"
1224                        "lw $4,8($29);\n"
1225 #endif
1226 #else
1227                        "ld $25,0($29);\n"
1228                        "ld $4,8($29);\n"
1229 #endif
1230                        "jal $25;\n"
1231
1232                        /* Call _exit($v0). */
1233                        "move $4,$2;\n"
1234                        "li $2,%7;\n"
1235                        "syscall;\n"
1236
1237                        /* Return to parent. */
1238                      "1:\n"
1239                        : "=r" (res)
1240                        : "r"(flags),
1241                          "r"(child_stack),
1242                          "r"(parent_tidptr),
1243                          "r"(a3),
1244                          "r"(a4),
1245                          "i"(__NR_clone),
1246                          "i"(__NR_exit)
1247                        : "memory", "$29" );
1248   return res;
1249 }
1250 #elif defined(__aarch64__)
1251 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1252                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1253   long long res;
1254   if (!fn || !child_stack)
1255     return -EINVAL;
1256   CHECK_EQ(0, (uptr)child_stack % 16);
1257   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1258   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1259   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1260
1261   register int (*__fn)(void *)  __asm__("x0") = fn;
1262   register void *__stack __asm__("x1") = child_stack;
1263   register int   __flags __asm__("x2") = flags;
1264   register void *__arg   __asm__("x3") = arg;
1265   register int  *__ptid  __asm__("x4") = parent_tidptr;
1266   register void *__tls   __asm__("x5") = newtls;
1267   register int  *__ctid  __asm__("x6") = child_tidptr;
1268
1269   __asm__ __volatile__(
1270                        "mov x0,x2\n" /* flags  */
1271                        "mov x2,x4\n" /* ptid  */
1272                        "mov x3,x5\n" /* tls  */
1273                        "mov x4,x6\n" /* ctid  */
1274                        "mov x8,%9\n" /* clone  */
1275
1276                        "svc 0x0\n"
1277
1278                        /* if (%r0 != 0)
1279                         *   return %r0;
1280                         */
1281                        "cmp x0, #0\n"
1282                        "bne 1f\n"
1283
1284                        /* In the child, now. Call "fn(arg)". */
1285                        "ldp x1, x0, [sp], #16\n"
1286                        "blr x1\n"
1287
1288                        /* Call _exit(%r0).  */
1289                        "mov x8, %10\n"
1290                        "svc 0x0\n"
1291                      "1:\n"
1292
1293                        : "=r" (res)
1294                        : "i"(-EINVAL),
1295                          "r"(__fn), "r"(__stack), "r"(__flags), "r"(__arg),
1296                          "r"(__ptid), "r"(__tls), "r"(__ctid),
1297                          "i"(__NR_clone), "i"(__NR_exit)
1298                        : "x30", "memory");
1299   return res;
1300 }
1301 #elif defined(__powerpc64__)
1302 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1303                    int *parent_tidptr, void *newtls, int *child_tidptr) {
1304   long long res;
1305 // Stack frame structure.
1306 #if SANITIZER_PPC64V1
1307 //   Back chain == 0        (SP + 112)
1308 // Frame (112 bytes):
1309 //   Parameter save area    (SP + 48), 8 doublewords
1310 //   TOC save area          (SP + 40)
1311 //   Link editor doubleword (SP + 32)
1312 //   Compiler doubleword    (SP + 24)
1313 //   LR save area           (SP + 16)
1314 //   CR save area           (SP + 8)
1315 //   Back chain             (SP + 0)
1316 # define FRAME_SIZE 112
1317 # define FRAME_TOC_SAVE_OFFSET 40
1318 #elif SANITIZER_PPC64V2
1319 //   Back chain == 0        (SP + 32)
1320 // Frame (32 bytes):
1321 //   TOC save area          (SP + 24)
1322 //   LR save area           (SP + 16)
1323 //   CR save area           (SP + 8)
1324 //   Back chain             (SP + 0)
1325 # define FRAME_SIZE 32
1326 # define FRAME_TOC_SAVE_OFFSET 24
1327 #else
1328 # error "Unsupported PPC64 ABI"
1329 #endif
1330   if (!fn || !child_stack)
1331     return -EINVAL;
1332   CHECK_EQ(0, (uptr)child_stack % 16);
1333
1334   register int (*__fn)(void *) __asm__("r3") = fn;
1335   register void *__cstack      __asm__("r4") = child_stack;
1336   register int __flags         __asm__("r5") = flags;
1337   register void *__arg         __asm__("r6") = arg;
1338   register int *__ptidptr      __asm__("r7") = parent_tidptr;
1339   register void *__newtls      __asm__("r8") = newtls;
1340   register int *__ctidptr      __asm__("r9") = child_tidptr;
1341
1342  __asm__ __volatile__(
1343            /* fn and arg are saved across the syscall */
1344            "mr 28, %5\n\t"
1345            "mr 27, %8\n\t"
1346
1347            /* syscall
1348              r0 == __NR_clone
1349              r3 == flags
1350              r4 == child_stack
1351              r5 == parent_tidptr
1352              r6 == newtls
1353              r7 == child_tidptr */
1354            "mr 3, %7\n\t"
1355            "mr 5, %9\n\t"
1356            "mr 6, %10\n\t"
1357            "mr 7, %11\n\t"
1358            "li 0, %3\n\t"
1359            "sc\n\t"
1360
1361            /* Test if syscall was successful */
1362            "cmpdi  cr1, 3, 0\n\t"
1363            "crandc cr1*4+eq, cr1*4+eq, cr0*4+so\n\t"
1364            "bne-   cr1, 1f\n\t"
1365
1366            /* Set up stack frame */
1367            "li    29, 0\n\t"
1368            "stdu  29, -8(1)\n\t"
1369            "stdu  1, -%12(1)\n\t"
1370            /* Do the function call */
1371            "std   2, %13(1)\n\t"
1372 #if SANITIZER_PPC64V1
1373            "ld    0, 0(28)\n\t"
1374            "ld    2, 8(28)\n\t"
1375            "mtctr 0\n\t"
1376 #elif SANITIZER_PPC64V2
1377            "mr    12, 28\n\t"
1378            "mtctr 12\n\t"
1379 #else
1380 # error "Unsupported PPC64 ABI"
1381 #endif
1382            "mr    3, 27\n\t"
1383            "bctrl\n\t"
1384            "ld    2, %13(1)\n\t"
1385
1386            /* Call _exit(r3) */
1387            "li 0, %4\n\t"
1388            "sc\n\t"
1389
1390            /* Return to parent */
1391            "1:\n\t"
1392            "mr %0, 3\n\t"
1393              : "=r" (res)
1394              : "0" (-1),
1395                "i" (EINVAL),
1396                "i" (__NR_clone),
1397                "i" (__NR_exit),
1398                "r" (__fn),
1399                "r" (__cstack),
1400                "r" (__flags),
1401                "r" (__arg),
1402                "r" (__ptidptr),
1403                "r" (__newtls),
1404                "r" (__ctidptr),
1405                "i" (FRAME_SIZE),
1406                "i" (FRAME_TOC_SAVE_OFFSET)
1407              : "cr0", "cr1", "memory", "ctr", "r0", "r27", "r28", "r29");
1408   return res;
1409 }
1410 #elif defined(__i386__) && SANITIZER_LINUX
1411 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1412                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1413   int res;
1414   if (!fn || !child_stack)
1415     return -EINVAL;
1416   CHECK_EQ(0, (uptr)child_stack % 16);
1417   child_stack = (char *)child_stack - 7 * sizeof(unsigned int);
1418   ((unsigned int *)child_stack)[0] = (uptr)flags;
1419   ((unsigned int *)child_stack)[1] = (uptr)0;
1420   ((unsigned int *)child_stack)[2] = (uptr)fn;
1421   ((unsigned int *)child_stack)[3] = (uptr)arg;
1422   __asm__ __volatile__(
1423                        /* %eax = syscall(%eax = SYSCALL(clone),
1424                         *                %ebx = flags,
1425                         *                %ecx = child_stack,
1426                         *                %edx = parent_tidptr,
1427                         *                %esi  = new_tls,
1428                         *                %edi = child_tidptr)
1429                         */
1430
1431                         /* Obtain flags */
1432                         "movl    (%%ecx), %%ebx\n"
1433                         /* Do the system call */
1434                         "pushl   %%ebx\n"
1435                         "pushl   %%esi\n"
1436                         "pushl   %%edi\n"
1437                         /* Remember the flag value.  */
1438                         "movl    %%ebx, (%%ecx)\n"
1439                         "int     $0x80\n"
1440                         "popl    %%edi\n"
1441                         "popl    %%esi\n"
1442                         "popl    %%ebx\n"
1443
1444                         /* if (%eax != 0)
1445                          *   return;
1446                          */
1447
1448                         "test    %%eax,%%eax\n"
1449                         "jnz    1f\n"
1450
1451                         /* terminate the stack frame */
1452                         "xorl   %%ebp,%%ebp\n"
1453                         /* Call FN. */
1454                         "call    *%%ebx\n"
1455 #ifdef PIC
1456                         "call    here\n"
1457                         "here:\n"
1458                         "popl    %%ebx\n"
1459                         "addl    $_GLOBAL_OFFSET_TABLE_+[.-here], %%ebx\n"
1460 #endif
1461                         /* Call exit */
1462                         "movl    %%eax, %%ebx\n"
1463                         "movl    %2, %%eax\n"
1464                         "int     $0x80\n"
1465                         "1:\n"
1466                        : "=a" (res)
1467                        : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
1468                          "c"(child_stack),
1469                          "d"(parent_tidptr),
1470                          "S"(newtls),
1471                          "D"(child_tidptr)
1472                        : "memory");
1473   return res;
1474 }
1475 #elif defined(__arm__) && SANITIZER_LINUX
1476 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1477                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1478   unsigned int res;
1479   if (!fn || !child_stack)
1480     return -EINVAL;
1481   child_stack = (char *)child_stack - 2 * sizeof(unsigned int);
1482   ((unsigned int *)child_stack)[0] = (uptr)fn;
1483   ((unsigned int *)child_stack)[1] = (uptr)arg;
1484   register int r0 __asm__("r0") = flags;
1485   register void *r1 __asm__("r1") = child_stack;
1486   register int *r2 __asm__("r2") = parent_tidptr;
1487   register void *r3 __asm__("r3") = newtls;
1488   register int *r4 __asm__("r4") = child_tidptr;
1489   register int r7 __asm__("r7") = __NR_clone;
1490
1491 #if __ARM_ARCH > 4 || defined (__ARM_ARCH_4T__)
1492 # define ARCH_HAS_BX
1493 #endif
1494 #if __ARM_ARCH > 4
1495 # define ARCH_HAS_BLX
1496 #endif
1497
1498 #ifdef ARCH_HAS_BX
1499 # ifdef ARCH_HAS_BLX
1500 #  define BLX(R) "blx "  #R "\n"
1501 # else
1502 #  define BLX(R) "mov lr, pc; bx " #R "\n"
1503 # endif
1504 #else
1505 # define BLX(R)  "mov lr, pc; mov pc," #R "\n"
1506 #endif
1507
1508   __asm__ __volatile__(
1509                        /* %r0 = syscall(%r7 = SYSCALL(clone),
1510                         *               %r0 = flags,
1511                         *               %r1 = child_stack,
1512                         *               %r2 = parent_tidptr,
1513                         *               %r3  = new_tls,
1514                         *               %r4 = child_tidptr)
1515                         */
1516
1517                        /* Do the system call */
1518                        "swi 0x0\n"
1519
1520                        /* if (%r0 != 0)
1521                         *   return %r0;
1522                         */
1523                        "cmp r0, #0\n"
1524                        "bne 1f\n"
1525
1526                        /* In the child, now. Call "fn(arg)". */
1527                        "ldr r0, [sp, #4]\n"
1528                        "ldr ip, [sp], #8\n"
1529                        BLX(ip)
1530                        /* Call _exit(%r0). */
1531                        "mov r7, %7\n"
1532                        "swi 0x0\n"
1533                        "1:\n"
1534                        "mov %0, r0\n"
1535                        : "=r"(res)
1536                        : "r"(r0), "r"(r1), "r"(r2), "r"(r3), "r"(r4), "r"(r7),
1537                          "i"(__NR_exit)
1538                        : "memory");
1539   return res;
1540 }
1541 #endif  // defined(__x86_64__) && SANITIZER_LINUX
1542
1543 #if SANITIZER_ANDROID
1544 #if __ANDROID_API__ < 21
1545 extern "C" __attribute__((weak)) int dl_iterate_phdr(
1546     int (*)(struct dl_phdr_info *, size_t, void *), void *);
1547 #endif
1548
1549 static int dl_iterate_phdr_test_cb(struct dl_phdr_info *info, size_t size,
1550                                    void *data) {
1551   // Any name starting with "lib" indicates a bug in L where library base names
1552   // are returned instead of paths.
1553   if (info->dlpi_name && info->dlpi_name[0] == 'l' &&
1554       info->dlpi_name[1] == 'i' && info->dlpi_name[2] == 'b') {
1555     *(bool *)data = true;
1556     return 1;
1557   }
1558   return 0;
1559 }
1560
1561 static atomic_uint32_t android_api_level;
1562
1563 static AndroidApiLevel AndroidDetectApiLevel() {
1564   if (!&dl_iterate_phdr)
1565     return ANDROID_KITKAT; // K or lower
1566   bool base_name_seen = false;
1567   dl_iterate_phdr(dl_iterate_phdr_test_cb, &base_name_seen);
1568   if (base_name_seen)
1569     return ANDROID_LOLLIPOP_MR1; // L MR1
1570   return ANDROID_POST_LOLLIPOP;   // post-L
1571   // Plain L (API level 21) is completely broken wrt ASan and not very
1572   // interesting to detect.
1573 }
1574
1575 AndroidApiLevel AndroidGetApiLevel() {
1576   AndroidApiLevel level =
1577       (AndroidApiLevel)atomic_load(&android_api_level, memory_order_relaxed);
1578   if (level) return level;
1579   level = AndroidDetectApiLevel();
1580   atomic_store(&android_api_level, level, memory_order_relaxed);
1581   return level;
1582 }
1583
1584 #endif
1585
1586 static HandleSignalMode GetHandleSignalModeImpl(int signum) {
1587   switch (signum) {
1588     case SIGABRT:
1589       return common_flags()->handle_abort;
1590     case SIGILL:
1591       return common_flags()->handle_sigill;
1592     case SIGFPE:
1593       return common_flags()->handle_sigfpe;
1594     case SIGSEGV:
1595       return common_flags()->handle_segv;
1596     case SIGBUS:
1597       return common_flags()->handle_sigbus;
1598   }
1599   return kHandleSignalNo;
1600 }
1601
1602 HandleSignalMode GetHandleSignalMode(int signum) {
1603   HandleSignalMode result = GetHandleSignalModeImpl(signum);
1604   if (result == kHandleSignalYes && !common_flags()->allow_user_segv_handler)
1605     return kHandleSignalExclusive;
1606   return result;
1607 }
1608
1609 #if !SANITIZER_GO
1610 void *internal_start_thread(void(*func)(void *arg), void *arg) {
1611   // Start the thread with signals blocked, otherwise it can steal user signals.
1612   __sanitizer_sigset_t set, old;
1613   internal_sigfillset(&set);
1614 #if SANITIZER_LINUX && !SANITIZER_ANDROID
1615   // Glibc uses SIGSETXID signal during setuid call. If this signal is blocked
1616   // on any thread, setuid call hangs (see test/tsan/setuid.c).
1617   internal_sigdelset(&set, 33);
1618 #endif
1619   internal_sigprocmask(SIG_SETMASK, &set, &old);
1620   void *th;
1621   real_pthread_create(&th, nullptr, (void*(*)(void *arg))func, arg);
1622   internal_sigprocmask(SIG_SETMASK, &old, nullptr);
1623   return th;
1624 }
1625
1626 void internal_join_thread(void *th) {
1627   real_pthread_join(th, nullptr);
1628 }
1629 #else
1630 void *internal_start_thread(void (*func)(void *), void *arg) { return 0; }
1631
1632 void internal_join_thread(void *th) {}
1633 #endif
1634
1635 #if defined(__aarch64__)
1636 // Android headers in the older NDK releases miss this definition.
1637 struct __sanitizer_esr_context {
1638   struct _aarch64_ctx head;
1639   uint64_t esr;
1640 };
1641
1642 static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
1643   static const u32 kEsrMagic = 0x45535201;
1644   u8 *aux = ucontext->uc_mcontext.__reserved;
1645   while (true) {
1646     _aarch64_ctx *ctx = (_aarch64_ctx *)aux;
1647     if (ctx->size == 0) break;
1648     if (ctx->magic == kEsrMagic) {
1649       *esr = ((__sanitizer_esr_context *)ctx)->esr;
1650       return true;
1651     }
1652     aux += ctx->size;
1653   }
1654   return false;
1655 }
1656 #endif
1657
1658 SignalContext::WriteFlag SignalContext::GetWriteFlag() const {
1659   ucontext_t *ucontext = (ucontext_t *)context;
1660 #if defined(__x86_64__) || defined(__i386__)
1661   static const uptr PF_WRITE = 1U << 1;
1662 #if SANITIZER_FREEBSD
1663   uptr err = ucontext->uc_mcontext.mc_err;
1664 #elif SANITIZER_NETBSD
1665   uptr err = ucontext->uc_mcontext.__gregs[_REG_ERR];
1666 #else
1667   uptr err = ucontext->uc_mcontext.gregs[REG_ERR];
1668 #endif
1669   return err & PF_WRITE ? WRITE : READ;
1670 #elif defined(__arm__)
1671   static const uptr FSR_WRITE = 1U << 11;
1672   uptr fsr = ucontext->uc_mcontext.error_code;
1673   return fsr & FSR_WRITE ? WRITE : READ;
1674 #elif defined(__aarch64__)
1675   static const u64 ESR_ELx_WNR = 1U << 6;
1676   u64 esr;
1677   if (!Aarch64GetESR(ucontext, &esr)) return UNKNOWN;
1678   return esr & ESR_ELx_WNR ? WRITE : READ;
1679 #else
1680   (void)ucontext;
1681   return UNKNOWN;  // FIXME: Implement.
1682 #endif
1683 }
1684
1685 void SignalContext::DumpAllRegisters(void *context) {
1686   // FIXME: Implement this.
1687 }
1688
1689 static void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
1690 #if defined(__arm__)
1691   ucontext_t *ucontext = (ucontext_t*)context;
1692   *pc = ucontext->uc_mcontext.arm_pc;
1693   *bp = ucontext->uc_mcontext.arm_fp;
1694   *sp = ucontext->uc_mcontext.arm_sp;
1695 #elif defined(__aarch64__)
1696   ucontext_t *ucontext = (ucontext_t*)context;
1697   *pc = ucontext->uc_mcontext.pc;
1698   *bp = ucontext->uc_mcontext.regs[29];
1699   *sp = ucontext->uc_mcontext.sp;
1700 #elif defined(__hppa__)
1701   ucontext_t *ucontext = (ucontext_t*)context;
1702   *pc = ucontext->uc_mcontext.sc_iaoq[0];
1703   /* GCC uses %r3 whenever a frame pointer is needed.  */
1704   *bp = ucontext->uc_mcontext.sc_gr[3];
1705   *sp = ucontext->uc_mcontext.sc_gr[30];
1706 #elif defined(__x86_64__)
1707 # if SANITIZER_FREEBSD
1708   ucontext_t *ucontext = (ucontext_t*)context;
1709   *pc = ucontext->uc_mcontext.mc_rip;
1710   *bp = ucontext->uc_mcontext.mc_rbp;
1711   *sp = ucontext->uc_mcontext.mc_rsp;
1712 #elif SANITIZER_NETBSD
1713   ucontext_t *ucontext = (ucontext_t *)context;
1714   *pc = ucontext->uc_mcontext.__gregs[_REG_RIP];
1715   *bp = ucontext->uc_mcontext.__gregs[_REG_RBP];
1716   *sp = ucontext->uc_mcontext.__gregs[_REG_RSP];
1717 # else
1718   ucontext_t *ucontext = (ucontext_t*)context;
1719   *pc = ucontext->uc_mcontext.gregs[REG_RIP];
1720   *bp = ucontext->uc_mcontext.gregs[REG_RBP];
1721   *sp = ucontext->uc_mcontext.gregs[REG_RSP];
1722 # endif
1723 #elif defined(__i386__)
1724 # if SANITIZER_FREEBSD
1725   ucontext_t *ucontext = (ucontext_t*)context;
1726   *pc = ucontext->uc_mcontext.mc_eip;
1727   *bp = ucontext->uc_mcontext.mc_ebp;
1728   *sp = ucontext->uc_mcontext.mc_esp;
1729 #elif SANITIZER_NETBSD
1730   ucontext_t *ucontext = (ucontext_t *)context;
1731   *pc = ucontext->uc_mcontext.__gregs[_REG_EIP];
1732   *bp = ucontext->uc_mcontext.__gregs[_REG_EBP];
1733   *sp = ucontext->uc_mcontext.__gregs[_REG_ESP];
1734 # else
1735   ucontext_t *ucontext = (ucontext_t*)context;
1736   *pc = ucontext->uc_mcontext.gregs[REG_EIP];
1737   *bp = ucontext->uc_mcontext.gregs[REG_EBP];
1738   *sp = ucontext->uc_mcontext.gregs[REG_ESP];
1739 # endif
1740 #elif defined(__powerpc__) || defined(__powerpc64__)
1741   ucontext_t *ucontext = (ucontext_t*)context;
1742   *pc = ucontext->uc_mcontext.regs->nip;
1743   *sp = ucontext->uc_mcontext.regs->gpr[PT_R1];
1744   // The powerpc{,64}-linux ABIs do not specify r31 as the frame
1745   // pointer, but GCC always uses r31 when we need a frame pointer.
1746   *bp = ucontext->uc_mcontext.regs->gpr[PT_R31];
1747 #elif defined(__sparc__)
1748   ucontext_t *ucontext = (ucontext_t*)context;
1749   uptr *stk_ptr;
1750 # if defined (__arch64__)
1751   *pc = ucontext->uc_mcontext.mc_gregs[MC_PC];
1752   *sp = ucontext->uc_mcontext.mc_gregs[MC_O6];
1753   stk_ptr = (uptr *) (*sp + 2047);
1754   *bp = stk_ptr[15];
1755 # else
1756   *pc = ucontext->uc_mcontext.gregs[REG_PC];
1757   *sp = ucontext->uc_mcontext.gregs[REG_O6];
1758   stk_ptr = (uptr *) *sp;
1759   *bp = stk_ptr[15];
1760 # endif
1761 #elif defined(__mips__)
1762   ucontext_t *ucontext = (ucontext_t*)context;
1763   *pc = ucontext->uc_mcontext.pc;
1764   *bp = ucontext->uc_mcontext.gregs[30];
1765   *sp = ucontext->uc_mcontext.gregs[29];
1766 #elif defined(__s390__)
1767   ucontext_t *ucontext = (ucontext_t*)context;
1768 # if defined(__s390x__)
1769   *pc = ucontext->uc_mcontext.psw.addr;
1770 # else
1771   *pc = ucontext->uc_mcontext.psw.addr & 0x7fffffff;
1772 # endif
1773   *bp = ucontext->uc_mcontext.gregs[11];
1774   *sp = ucontext->uc_mcontext.gregs[15];
1775 #else
1776 # error "Unsupported arch"
1777 #endif
1778 }
1779
1780 void SignalContext::InitPcSpBp() { GetPcSpBp(context, &pc, &sp, &bp); }
1781
1782 void MaybeReexec() {
1783   // No need to re-exec on Linux.
1784 }
1785
1786 void PrintModuleMap() { }
1787
1788 void CheckNoDeepBind(const char *filename, int flag) {
1789 #ifdef RTLD_DEEPBIND
1790   if (flag & RTLD_DEEPBIND) {
1791     Report(
1792         "You are trying to dlopen a %s shared library with RTLD_DEEPBIND flag"
1793         " which is incompatibe with sanitizer runtime "
1794         "(see https://github.com/google/sanitizers/issues/611 for details"
1795         "). If you want to run %s library under sanitizers please remove "
1796         "RTLD_DEEPBIND from dlopen flags.\n",
1797         filename, filename);
1798     Die();
1799   }
1800 #endif
1801 }
1802
1803 uptr FindAvailableMemoryRange(uptr size, uptr alignment, uptr left_padding,
1804                               uptr *largest_gap_found) {
1805   UNREACHABLE("FindAvailableMemoryRange is not available");
1806   return 0;
1807 }
1808
1809 bool GetRandom(void *buffer, uptr length, bool blocking) {
1810   if (!buffer || !length || length > 256)
1811     return false;
1812 #if SANITIZER_USE_GETRANDOM
1813   static atomic_uint8_t skip_getrandom_syscall;
1814   if (!atomic_load_relaxed(&skip_getrandom_syscall)) {
1815     // Up to 256 bytes, getrandom will not be interrupted.
1816     uptr res = internal_syscall(SYSCALL(getrandom), buffer, length,
1817                                 blocking ? 0 : GRND_NONBLOCK);
1818     int rverrno = 0;
1819     if (internal_iserror(res, &rverrno) && rverrno == ENOSYS)
1820       atomic_store_relaxed(&skip_getrandom_syscall, 1);
1821     else if (res == length)
1822       return true;
1823   }
1824 #endif  // SANITIZER_USE_GETRANDOM
1825   // Up to 256 bytes, a read off /dev/urandom will not be interrupted.
1826   // blocking is moot here, O_NONBLOCK has no effect when opening /dev/urandom.
1827   uptr fd = internal_open("/dev/urandom", O_RDONLY);
1828   if (internal_iserror(fd))
1829     return false;
1830   uptr res = internal_read(fd, buffer, length);
1831   if (internal_iserror(res))
1832     return false;
1833   internal_close(fd);
1834   return true;
1835 }
1836
1837 } // namespace __sanitizer
1838
1839 #endif  // SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD