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 #if SANITIZER_FREEBSD || SANITIZER_LINUX
  15
  16 #include "sanitizer_common.h"
  17 #include "sanitizer_flags.h"
  18 #include "sanitizer_internal_defs.h"
  19 #include "sanitizer_libc.h"
  20 #include "sanitizer_linux.h"
  21 #include "sanitizer_mutex.h"
  22 #include "sanitizer_placement_new.h"
  23 #include "sanitizer_procmaps.h"
  24 #include "sanitizer_stacktrace.h"
  25 #include "sanitizer_symbolizer.h"
  26
  27 #if !SANITIZER_FREEBSD
  28 #include <asm/param.h>
  29 #endif
  30
  31 #include <dlfcn.h>
  32 #include <errno.h>
  33 #include <fcntl.h>
  34 #if !SANITIZER_ANDROID
  35 #include <link.h>
  36 #endif
  37 #include <pthread.h>
  38 #include <sched.h>
  39 #include <sys/mman.h>
  40 #include <sys/ptrace.h>
  41 #include <sys/resource.h>
  42 #include <sys/stat.h>
  43 #include <sys/syscall.h>
  44 #include <sys/time.h>
  45 #include <sys/types.h>
  46 #include <unistd.h>
  47
  48 #if SANITIZER_FREEBSD
  49 #include <sys/sysctl.h>
  50 #include <machine/atomic.h>
  51 extern "C" {
  52 // <sys/umtx.h> must be included after <errno.h> and <sys/types.h> on
  53 // FreeBSD 9.2 and 10.0.
  54 #include <sys/umtx.h>
  55 }
  56 extern char **environ;  // provided by crt1
  57 #endif  // SANITIZER_FREEBSD
  58
  59 #if !SANITIZER_ANDROID
  60 #include <sys/signal.h>
  61 #endif
  62
  63 #if SANITIZER_ANDROID
  64 #include <android/log.h>
  65 #include <sys/system_properties.h>
  66 #endif
  67
  68 #if SANITIZER_LINUX
  69 // <linux/time.h>
  70 struct kernel_timeval {
  71   long tv_sec;
  72   long tv_usec;
  73 };
  74
  75 // <linux/futex.h> is broken on some linux distributions.
  76 const int FUTEX_WAIT = 0;
  77 const int FUTEX_WAKE = 1;
  78 #endif  // SANITIZER_LINUX
  79
  80 // Are we using 32-bit or 64-bit Linux syscalls?
  81 // x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 32
  82 // but it still needs to use 64-bit syscalls.
  83 #if SANITIZER_LINUX && (defined(__x86_64__) || SANITIZER_WORDSIZE == 64)
  84 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 1
  85 #else
  86 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 0
  87 #endif
  88
  89 namespace __sanitizer {
  90
  91 #if SANITIZER_LINUX && defined(__x86_64__)
  92 #include "sanitizer_syscall_linux_x86_64.inc"
  93 #else
  94 #include "sanitizer_syscall_generic.inc"
  95 #endif
  96
  97 // --------------- sanitizer_libc.h
  98 uptr internal_mmap(void *addr, uptr length, int prot, int flags,
  99                     int fd, u64 offset) {
 100 #if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
 101   return internal_syscall(SYSCALL(mmap), (uptr)addr, length, prot, flags, fd,
 102                           offset);
 103 #else
 104   return internal_syscall(SYSCALL(mmap2), addr, length, prot, flags, fd,
 105                           offset);
 106 #endif
 107 }
 108
 109 uptr internal_munmap(void *addr, uptr length) {
 110   return internal_syscall(SYSCALL(munmap), (uptr)addr, length);
 111 }
 112
 113 uptr internal_close(fd_t fd) {
 114   return internal_syscall(SYSCALL(close), fd);
 115 }
 116
 117 uptr internal_open(const char *filename, int flags) {
 118 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 119   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags);
 120 #else
 121   return internal_syscall(SYSCALL(open), (uptr)filename, flags);
 122 #endif
 123 }
 124
 125 uptr internal_open(const char *filename, int flags, u32 mode) {
 126 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 127   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags,
 128                           mode);
 129 #else
 130   return internal_syscall(SYSCALL(open), (uptr)filename, flags, mode);
 131 #endif
 132 }
 133
 134 uptr OpenFile(const char *filename, bool write) {
 135   return internal_open(filename,
 136       write ? O_RDWR | O_CREAT /*| O_CLOEXEC*/ : O_RDONLY, 0660);
 137 }
 138
 139 uptr internal_read(fd_t fd, void *buf, uptr count) {
 140   sptr res;
 141   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(read), fd, (uptr)buf,
 142                count));
 143   return res;
 144 }
 145
 146 uptr internal_write(fd_t fd, const void *buf, uptr count) {
 147   sptr res;
 148   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(write), fd, (uptr)buf,
 149                count));
 150   return res;
 151 }
 152
 153 uptr internal_ftruncate(fd_t fd, uptr size) {
 154   sptr res;
 155   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(ftruncate), fd, size));
 156   return res;
 157 }
 158
 159 #if !SANITIZER_LINUX_USES_64BIT_SYSCALLS && !SANITIZER_FREEBSD
 160 static void stat64_to_stat(struct stat64 *in, struct stat *out) {
 161   internal_memset(out, 0, sizeof(*out));
 162   out->st_dev = in->st_dev;
 163   out->st_ino = in->st_ino;
 164   out->st_mode = in->st_mode;
 165   out->st_nlink = in->st_nlink;
 166   out->st_uid = in->st_uid;
 167   out->st_gid = in->st_gid;
 168   out->st_rdev = in->st_rdev;
 169   out->st_size = in->st_size;
 170   out->st_blksize = in->st_blksize;
 171   out->st_blocks = in->st_blocks;
 172   out->st_atime = in->st_atime;
 173   out->st_mtime = in->st_mtime;
 174   out->st_ctime = in->st_ctime;
 175   out->st_ino = in->st_ino;
 176 }
 177 #endif
 178
 179 uptr internal_stat(const char *path, void *buf) {
 180 #if SANITIZER_FREEBSD
 181   return internal_syscall(SYSCALL(stat), path, buf);
 182 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 183   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path,
 184                           (uptr)buf, 0);
 185 #elif SANITIZER_LINUX_USES_64BIT_SYSCALLS
 186   return internal_syscall(SYSCALL(stat), (uptr)path, (uptr)buf);
 187 #else
 188   struct stat64 buf64;
 189   int res = internal_syscall(SYSCALL(stat64), path, &buf64);
 190   stat64_to_stat(&buf64, (struct stat *)buf);
 191   return res;
 192 #endif
 193 }
 194
 195 uptr internal_lstat(const char *path, void *buf) {
 196 #if SANITIZER_FREEBSD
 197   return internal_syscall(SYSCALL(lstat), path, buf);
 198 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 199   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path,
 200                          (uptr)buf, AT_SYMLINK_NOFOLLOW);
 201 #elif SANITIZER_LINUX_USES_64BIT_SYSCALLS
 202   return internal_syscall(SYSCALL(lstat), (uptr)path, (uptr)buf);
 203 #else
 204   struct stat64 buf64;
 205   int res = internal_syscall(SYSCALL(lstat64), path, &buf64);
 206   stat64_to_stat(&buf64, (struct stat *)buf);
 207   return res;
 208 #endif
 209 }
 210
 211 uptr internal_fstat(fd_t fd, void *buf) {
 212 #if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
 213   return internal_syscall(SYSCALL(fstat), fd, (uptr)buf);
 214 #else
 215   struct stat64 buf64;
 216   int res = internal_syscall(SYSCALL(fstat64), fd, &buf64);
 217   stat64_to_stat(&buf64, (struct stat *)buf);
 218   return res;
 219 #endif
 220 }
 221
 222 uptr internal_filesize(fd_t fd) {
 223   struct stat st;
 224   if (internal_fstat(fd, &st))
 225     return -1;
 226   return (uptr)st.st_size;
 227 }
 228
 229 uptr internal_dup2(int oldfd, int newfd) {
 230 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 231   return internal_syscall(SYSCALL(dup3), oldfd, newfd, 0);
 232 #else
 233   return internal_syscall(SYSCALL(dup2), oldfd, newfd);
 234 #endif
 235 }
 236
 237 uptr internal_readlink(const char *path, char *buf, uptr bufsize) {
 238 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 239   return internal_syscall(SYSCALL(readlinkat), AT_FDCWD,
 240                           (uptr)path, (uptr)buf, bufsize);
 241 #else
 242   return internal_syscall(SYSCALL(readlink), (uptr)path, (uptr)buf, bufsize);
 243 #endif
 244 }
 245
 246 uptr internal_unlink(const char *path) {
 247 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 248   return internal_syscall(SYSCALL(unlinkat), AT_FDCWD, (uptr)path, 0);
 249 #else
 250   return internal_syscall(SYSCALL(unlink), (uptr)path);
 251 #endif
 252 }
 253
 254 uptr internal_rename(const char *oldpath, const char *newpath) {
 255 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 256   return internal_syscall(SYSCALL(renameat), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
 257                           (uptr)newpath);
 258 #else
 259   return internal_syscall(SYSCALL(rename), (uptr)oldpath, (uptr)newpath);
 260 #endif
 261 }
 262
 263 uptr internal_sched_yield() {
 264   return internal_syscall(SYSCALL(sched_yield));
 265 }
 266
 267 void internal__exit(int exitcode) {
 268 #if SANITIZER_FREEBSD
 269   internal_syscall(SYSCALL(exit), exitcode);
 270 #else
 271   internal_syscall(SYSCALL(exit_group), exitcode);
 272 #endif
 273   Die();  // Unreachable.
 274 }
 275
 276 uptr internal_execve(const char *filename, char *const argv[],
 277                      char *const envp[]) {
 278   return internal_syscall(SYSCALL(execve), (uptr)filename, (uptr)argv,
 279                           (uptr)envp);
 280 }
 281
 282 // ----------------- sanitizer_common.h
 283 bool FileExists(const char *filename) {
 284   struct stat st;
 285 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 286   if (internal_syscall(SYSCALL(newfstatat), AT_FDCWD, filename, &st, 0))
 287 #else
 288   if (internal_stat(filename, &st))
 289 #endif
 290     return false;
 291   // Sanity check: filename is a regular file.
 292   return S_ISREG(st.st_mode);
 293 }
 294
 295 uptr GetTid() {
 296 #if SANITIZER_FREEBSD
 297   return (uptr)pthread_self();
 298 #else
 299   return internal_syscall(SYSCALL(gettid));
 300 #endif
 301 }
 302
 303 u64 NanoTime() {
 304 #if SANITIZER_FREEBSD
 305   timeval tv;
 306 #else
 307   kernel_timeval tv;
 308 #endif
 309   internal_memset(&tv, 0, sizeof(tv));
 310   internal_syscall(SYSCALL(gettimeofday), (uptr)&tv, 0);
 311   return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000;
 312 }
 313
 314 // Like getenv, but reads env directly from /proc (on Linux) or parses the
 315 // 'environ' array (on FreeBSD) and does not use libc. This function should be
 316 // called first inside __asan_init.
 317 const char *GetEnv(const char *name) {
 318 #if SANITIZER_FREEBSD
 319   if (::environ != 0) {
 320     uptr NameLen = internal_strlen(name);
 321     for (char **Env = ::environ; *Env != 0; Env++) {
 322       if (internal_strncmp(*Env, name, NameLen) == 0 && (*Env)[NameLen] == '=')
 323         return (*Env) + NameLen + 1;
 324     }
 325   }
 326   return 0;  // Not found.
 327 #elif SANITIZER_LINUX
 328   static char *environ;
 329   static uptr len;
 330   static bool inited;
 331   if (!inited) {
 332     inited = true;
 333     uptr environ_size;
 334     len = ReadFileToBuffer("/proc/self/environ",
 335                            &environ, &environ_size, 1 << 26);
 336   }
 337   if (!environ || len == 0) return 0;
 338   uptr namelen = internal_strlen(name);
 339   const char *p = environ;
 340   while (*p != '\0') {  // will happen at the \0\0 that terminates the buffer
 341     // proc file has the format NAME=value\0NAME=value\0NAME=value\0...
 342     const char* endp =
 343         (char*)internal_memchr(p, '\0', len - (p - environ));
 344     if (endp == 0)  // this entry isn't NUL terminated
 345       return 0;
 346     else if (!internal_memcmp(p, name, namelen) && p[namelen] == '=')  // Match.
 347       return p + namelen + 1;  // point after =
 348     p = endp + 1;
 349   }
 350   return 0;  // Not found.
 351 #else
 352 #error "Unsupported platform"
 353 #endif
 354 }
 355
 356 extern "C" {
 357   SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end;
 358 }
 359
 360 #if !SANITIZER_GO
 361 static void ReadNullSepFileToArray(const char *path, char ***arr,
 362                                    int arr_size) {
 363   char *buff;
 364   uptr buff_size = 0;
 365   *arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray");
 366   ReadFileToBuffer(path, &buff, &buff_size, 1024 * 1024);
 367   (*arr)[0] = buff;
 368   int count, i;
 369   for (count = 1, i = 1; ; i++) {
 370     if (buff[i] == 0) {
 371       if (buff[i+1] == 0) break;
 372       (*arr)[count] = &buff[i+1];
 373       CHECK_LE(count, arr_size - 1);  // FIXME: make this more flexible.
 374       count++;
 375     }
 376   }
 377   (*arr)[count] = 0;
 378 }
 379 #endif
 380
 381 static void GetArgsAndEnv(char*** argv, char*** envp) {
 382 #if !SANITIZER_GO
 383   if (&__libc_stack_end) {
 384 #endif
 385     uptr* stack_end = (uptr*)__libc_stack_end;
 386     int argc = *stack_end;
 387     *argv = (char**)(stack_end + 1);
 388     *envp = (char**)(stack_end + argc + 2);
 389 #if !SANITIZER_GO
 390   } else {
 391     static const int kMaxArgv = 2000, kMaxEnvp = 2000;
 392     ReadNullSepFileToArray("/proc/self/cmdline", argv, kMaxArgv);
 393     ReadNullSepFileToArray("/proc/self/environ", envp, kMaxEnvp);
 394   }
 395 #endif
 396 }
 397
 398 void ReExec() {
 399   char **argv, **envp;
 400   GetArgsAndEnv(&argv, &envp);
 401   uptr rv = internal_execve("/proc/self/exe", argv, envp);
 402   int rverrno;
 403   CHECK_EQ(internal_iserror(rv, &rverrno), true);
 404   Printf("execve failed, errno %d\n", rverrno);
 405   Die();
 406 }
 407
 408 // Stub implementation of GetThreadStackAndTls for Go.
 409 #if SANITIZER_GO
 410 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
 411                           uptr *tls_addr, uptr *tls_size) {
 412   *stk_addr = 0;
 413   *stk_size = 0;
 414   *tls_addr = 0;
 415   *tls_size = 0;
 416 }
 417 #endif  // SANITIZER_GO
 418
 419 enum MutexState {
 420   MtxUnlocked = 0,
 421   MtxLocked = 1,
 422   MtxSleeping = 2
 423 };
 424
 425 BlockingMutex::BlockingMutex(LinkerInitialized) {
 426   CHECK_EQ(owner_, 0);
 427 }
 428
 429 BlockingMutex::BlockingMutex() {
 430   internal_memset(this, 0, sizeof(*this));
 431 }
 432
 433 void BlockingMutex::Lock() {
 434   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
 435   if (atomic_exchange(m, MtxLocked, memory_order_acquire) == MtxUnlocked)
 436     return;
 437   while (atomic_exchange(m, MtxSleeping, memory_order_acquire) != MtxUnlocked) {
 438 #if SANITIZER_FREEBSD
 439     _umtx_op(m, UMTX_OP_WAIT_UINT, MtxSleeping, 0, 0);
 440 #else
 441     internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAIT, MtxSleeping, 0, 0, 0);
 442 #endif
 443   }
 444 }
 445
 446 void BlockingMutex::Unlock() {
 447   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
 448   u32 v = atomic_exchange(m, MtxUnlocked, memory_order_relaxed);
 449   CHECK_NE(v, MtxUnlocked);
 450   if (v == MtxSleeping) {
 451 #if SANITIZER_FREEBSD
 452     _umtx_op(m, UMTX_OP_WAKE, 1, 0, 0);
 453 #else
 454     internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAKE, 1, 0, 0, 0);
 455 #endif
 456   }
 457 }
 458
 459 void BlockingMutex::CheckLocked() {
 460   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
 461   CHECK_NE(MtxUnlocked, atomic_load(m, memory_order_relaxed));
 462 }
 463
 464 // ----------------- sanitizer_linux.h
 465 // The actual size of this structure is specified by d_reclen.
 466 // Note that getdents64 uses a different structure format. We only provide the
 467 // 32-bit syscall here.
 468 struct linux_dirent {
 469 #if SANITIZER_X32
 470   u64 d_ino;
 471   u64 d_off;
 472 #else
 473   unsigned long      d_ino;
 474   unsigned long      d_off;
 475 #endif
 476   unsigned short     d_reclen;
 477   char               d_name[256];
 478 };
 479
 480 // Syscall wrappers.
 481 uptr internal_ptrace(int request, int pid, void *addr, void *data) {
 482   return internal_syscall(SYSCALL(ptrace), request, pid, (uptr)addr,
 483                           (uptr)data);
 484 }
 485
 486 uptr internal_waitpid(int pid, int *status, int options) {
 487   return internal_syscall(SYSCALL(wait4), pid, (uptr)status, options,
 488                           0 /* rusage */);
 489 }
 490
 491 uptr internal_getpid() {
 492   return internal_syscall(SYSCALL(getpid));
 493 }
 494
 495 uptr internal_getppid() {
 496   return internal_syscall(SYSCALL(getppid));
 497 }
 498
 499 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) {
 500 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 501   return internal_syscall(SYSCALL(getdents64), fd, (uptr)dirp, count);
 502 #else
 503   return internal_syscall(SYSCALL(getdents), fd, (uptr)dirp, count);
 504 #endif
 505 }
 506
 507 uptr internal_lseek(fd_t fd, OFF_T offset, int whence) {
 508   return internal_syscall(SYSCALL(lseek), fd, offset, whence);
 509 }
 510
 511 #if SANITIZER_LINUX
 512 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) {
 513   return internal_syscall(SYSCALL(prctl), option, arg2, arg3, arg4, arg5);
 514 }
 515 #endif
 516
 517 uptr internal_sigaltstack(const struct sigaltstack *ss,
 518                          struct sigaltstack *oss) {
 519   return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
 520 }
 521
 522 int internal_fork() {
 523 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 524   return internal_syscall(SYSCALL(clone), SIGCHLD, 0);
 525 #else
 526   return internal_syscall(SYSCALL(fork));
 527 #endif
 528 }
 529
 530 #if SANITIZER_LINUX
 531 // Doesn't set sa_restorer, use with caution (see below).
 532 int internal_sigaction_norestorer(int signum, const void *act, void *oldact) {
 533   __sanitizer_kernel_sigaction_t k_act, k_oldact;
 534   internal_memset(&k_act, 0, sizeof(__sanitizer_kernel_sigaction_t));
 535   internal_memset(&k_oldact, 0, sizeof(__sanitizer_kernel_sigaction_t));
 536   const __sanitizer_sigaction *u_act = (__sanitizer_sigaction *)act;
 537   __sanitizer_sigaction *u_oldact = (__sanitizer_sigaction *)oldact;
 538   if (u_act) {
 539     k_act.handler = u_act->handler;
 540     k_act.sigaction = u_act->sigaction;
 541     internal_memcpy(&k_act.sa_mask, &u_act->sa_mask,
 542                     sizeof(__sanitizer_kernel_sigset_t));
 543     k_act.sa_flags = u_act->sa_flags;
 544     // FIXME: most often sa_restorer is unset, however the kernel requires it
 545     // to point to a valid signal restorer that calls the rt_sigreturn syscall.
 546     // If sa_restorer passed to the kernel is NULL, the program may crash upon
 547     // signal delivery or fail to unwind the stack in the signal handler.
 548     // libc implementation of sigaction() passes its own restorer to
 549     // rt_sigaction, so we need to do the same (we'll need to reimplement the
 550     // restorers; for x86_64 the restorer address can be obtained from
 551     // oldact->sa_restorer upon a call to sigaction(xxx, NULL, oldact).
 552     k_act.sa_restorer = u_act->sa_restorer;
 553   }
 554
 555   uptr result = internal_syscall(SYSCALL(rt_sigaction), (uptr)signum,
 556       (uptr)(u_act ? &k_act : NULL),
 557       (uptr)(u_oldact ? &k_oldact : NULL),
 558       (uptr)sizeof(__sanitizer_kernel_sigset_t));
 559
 560   if ((result == 0) && u_oldact) {
 561     u_oldact->handler = k_oldact.handler;
 562     u_oldact->sigaction = k_oldact.sigaction;
 563     internal_memcpy(&u_oldact->sa_mask, &k_oldact.sa_mask,
 564                     sizeof(__sanitizer_kernel_sigset_t));
 565     u_oldact->sa_flags = k_oldact.sa_flags;
 566     u_oldact->sa_restorer = k_oldact.sa_restorer;
 567   }
 568   return result;
 569 }
 570 #endif  // SANITIZER_LINUX
 571
 572 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
 573     __sanitizer_sigset_t *oldset) {
 574 #if SANITIZER_FREEBSD
 575   return internal_syscall(SYSCALL(sigprocmask), how, set, oldset);
 576 #else
 577   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
 578   __sanitizer_kernel_sigset_t *k_oldset = (__sanitizer_kernel_sigset_t *)oldset;
 579   return internal_syscall(SYSCALL(rt_sigprocmask), (uptr)how,
 580                           (uptr)&k_set->sig[0], (uptr)&k_oldset->sig[0],
 581                           sizeof(__sanitizer_kernel_sigset_t));
 582 #endif
 583 }
 584
 585 void internal_sigfillset(__sanitizer_sigset_t *set) {
 586   internal_memset(set, 0xff, sizeof(*set));
 587 }
 588
 589 #if SANITIZER_LINUX
 590 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
 591   signum -= 1;
 592   CHECK_GE(signum, 0);
 593   CHECK_LT(signum, sizeof(*set) * 8);
 594   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
 595   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
 596   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
 597   k_set->sig[idx] &= ~(1 << bit);
 598 }
 599 #endif  // SANITIZER_LINUX
 600
 601 // ThreadLister implementation.
 602 ThreadLister::ThreadLister(int pid)
 603   : pid_(pid),
 604     descriptor_(-1),
 605     buffer_(4096),
 606     error_(true),
 607     entry_((struct linux_dirent *)buffer_.data()),
 608     bytes_read_(0) {
 609   char task_directory_path[80];
 610   internal_snprintf(task_directory_path, sizeof(task_directory_path),
 611                     "/proc/%d/task/", pid);
 612   uptr openrv = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY);
 613   if (internal_iserror(openrv)) {
 614     error_ = true;
 615     Report("Can't open /proc/%d/task for reading.\n", pid);
 616   } else {
 617     error_ = false;
 618     descriptor_ = openrv;
 619   }
 620 }
 621
 622 int ThreadLister::GetNextTID() {
 623   int tid = -1;
 624   do {
 625     if (error_)
 626       return -1;
 627     if ((char *)entry_ >= &buffer_[bytes_read_] && !GetDirectoryEntries())
 628       return -1;
 629     if (entry_->d_ino != 0 && entry_->d_name[0] >= '0' &&
 630         entry_->d_name[0] <= '9') {
 631       // Found a valid tid.
 632       tid = (int)internal_atoll(entry_->d_name);
 633     }
 634     entry_ = (struct linux_dirent *)(((char *)entry_) + entry_->d_reclen);
 635   } while (tid < 0);
 636   return tid;
 637 }
 638
 639 void ThreadLister::Reset() {
 640   if (error_ || descriptor_ < 0)
 641     return;
 642   internal_lseek(descriptor_, 0, SEEK_SET);
 643 }
 644
 645 ThreadLister::~ThreadLister() {
 646   if (descriptor_ >= 0)
 647     internal_close(descriptor_);
 648 }
 649
 650 bool ThreadLister::error() { return error_; }
 651
 652 bool ThreadLister::GetDirectoryEntries() {
 653   CHECK_GE(descriptor_, 0);
 654   CHECK_NE(error_, true);
 655   bytes_read_ = internal_getdents(descriptor_,
 656                                   (struct linux_dirent *)buffer_.data(),
 657                                   buffer_.size());
 658   if (internal_iserror(bytes_read_)) {
 659     Report("Can't read directory entries from /proc/%d/task.\n", pid_);
 660     error_ = true;
 661     return false;
 662   } else if (bytes_read_ == 0) {
 663     return false;
 664   }
 665   entry_ = (struct linux_dirent *)buffer_.data();
 666   return true;
 667 }
 668
 669 uptr GetPageSize() {
 670 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__))
 671   return EXEC_PAGESIZE;
 672 #else
 673   return sysconf(_SC_PAGESIZE);  // EXEC_PAGESIZE may not be trustworthy.
 674 #endif
 675 }
 676
 677 static char proc_self_exe_cache_str[kMaxPathLength];
 678 static uptr proc_self_exe_cache_len = 0;
 679
 680 uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
 681   if (proc_self_exe_cache_len > 0) {
 682     // If available, use the cached module name.
 683     uptr module_name_len =
 684         internal_snprintf(buf, buf_len, "%s", proc_self_exe_cache_str);
 685     CHECK_LT(module_name_len, buf_len);
 686     return module_name_len;
 687   }
 688 #if SANITIZER_FREEBSD
 689   const int Mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1 };
 690   size_t Size = buf_len;
 691   bool IsErr = (sysctl(Mib, 4, buf, &Size, NULL, 0) != 0);
 692   int readlink_error = IsErr ? errno : 0;
 693   uptr module_name_len = Size;
 694 #else
 695   uptr module_name_len = internal_readlink(
 696       "/proc/self/exe", buf, buf_len);
 697   int readlink_error;
 698   bool IsErr = internal_iserror(module_name_len, &readlink_error);
 699 #endif
 700   if (IsErr) {
 701     // We can't read /proc/self/exe for some reason, assume the name of the
 702     // binary is unknown.
 703     Report("WARNING: readlink(\"/proc/self/exe\") failed with errno %d, "
 704            "some stack frames may not be symbolized\n", readlink_error);
 705     module_name_len = internal_snprintf(buf, buf_len, "/proc/self/exe");
 706     CHECK_LT(module_name_len, buf_len);
 707   }
 708   return module_name_len;
 709 }
 710
 711 void CacheBinaryName() {
 712   if (!proc_self_exe_cache_len) {
 713     proc_self_exe_cache_len =
 714         ReadBinaryName(proc_self_exe_cache_str, kMaxPathLength);
 715   }
 716 }
 717
 718 // Match full names of the form /path/to/base_name{-,.}*
 719 bool LibraryNameIs(const char *full_name, const char *base_name) {
 720   const char *name = full_name;
 721   // Strip path.
 722   while (*name != '\0') name++;
 723   while (name > full_name && *name != '/') name--;
 724   if (*name == '/') name++;
 725   uptr base_name_length = internal_strlen(base_name);
 726   if (internal_strncmp(name, base_name, base_name_length)) return false;
 727   return (name[base_name_length] == '-' || name[base_name_length] == '.');
 728 }
 729
 730 #if !SANITIZER_ANDROID
 731 // Call cb for each region mapped by map.
 732 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) {
 733 #if !SANITIZER_FREEBSD
 734   typedef ElfW(Phdr) Elf_Phdr;
 735   typedef ElfW(Ehdr) Elf_Ehdr;
 736 #endif  // !SANITIZER_FREEBSD
 737   char *base = (char *)map->l_addr;
 738   Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
 739   char *phdrs = base + ehdr->e_phoff;
 740   char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize;
 741
 742   // Find the segment with the minimum base so we can "relocate" the p_vaddr
 743   // fields.  Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC
 744   // objects have a non-zero base.
 745   uptr preferred_base = (uptr)-1;
 746   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
 747     Elf_Phdr *phdr = (Elf_Phdr *)iter;
 748     if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr)
 749       preferred_base = (uptr)phdr->p_vaddr;
 750   }
 751
 752   // Compute the delta from the real base to get a relocation delta.
 753   sptr delta = (uptr)base - preferred_base;
 754   // Now we can figure out what the loader really mapped.
 755   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
 756     Elf_Phdr *phdr = (Elf_Phdr *)iter;
 757     if (phdr->p_type == PT_LOAD) {
 758       uptr seg_start = phdr->p_vaddr + delta;
 759       uptr seg_end = seg_start + phdr->p_memsz;
 760       // None of these values are aligned.  We consider the ragged edges of the
 761       // load command as defined, since they are mapped from the file.
 762       seg_start = RoundDownTo(seg_start, GetPageSizeCached());
 763       seg_end = RoundUpTo(seg_end, GetPageSizeCached());
 764       cb((void *)seg_start, seg_end - seg_start);
 765     }
 766   }
 767 }
 768 #endif
 769
 770 #if defined(__x86_64__) && SANITIZER_LINUX
 771 // We cannot use glibc's clone wrapper, because it messes with the child
 772 // task's TLS. It writes the PID and TID of the child task to its thread
 773 // descriptor, but in our case the child task shares the thread descriptor with
 774 // the parent (because we don't know how to allocate a new thread
 775 // descriptor to keep glibc happy). So the stock version of clone(), when
 776 // used with CLONE_VM, would end up corrupting the parent's thread descriptor.
 777 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
 778                     int *parent_tidptr, void *newtls, int *child_tidptr) {
 779   long long res;
 780   if (!fn || !child_stack)
 781     return -EINVAL;
 782   CHECK_EQ(0, (uptr)child_stack % 16);
 783   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
 784   ((unsigned long long *)child_stack)[0] = (uptr)fn;
 785   ((unsigned long long *)child_stack)[1] = (uptr)arg;
 786   register void *r8 __asm__("r8") = newtls;
 787   register int *r10 __asm__("r10") = child_tidptr;
 788   __asm__ __volatile__(
 789                        /* %rax = syscall(%rax = SYSCALL(clone),
 790                         *                %rdi = flags,
 791                         *                %rsi = child_stack,
 792                         *                %rdx = parent_tidptr,
 793                         *                %r8  = new_tls,
 794                         *                %r10 = child_tidptr)
 795                         */
 796                        "syscall\n"
 797
 798                        /* if (%rax != 0)
 799                         *   return;
 800                         */
 801                        "testq  %%rax,%%rax\n"
 802                        "jnz    1f\n"
 803
 804                        /* In the child. Terminate unwind chain. */
 805                        // XXX: We should also terminate the CFI unwind chain
 806                        // here. Unfortunately clang 3.2 doesn't support the
 807                        // necessary CFI directives, so we skip that part.
 808                        "xorq   %%rbp,%%rbp\n"
 809
 810                        /* Call "fn(arg)". */
 811                        "popq   %%rax\n"
 812                        "popq   %%rdi\n"
 813                        "call   *%%rax\n"
 814
 815                        /* Call _exit(%rax). */
 816                        "movq   %%rax,%%rdi\n"
 817                        "movq   %2,%%rax\n"
 818                        "syscall\n"
 819
 820                        /* Return to parent. */
 821                      "1:\n"
 822                        : "=a" (res)
 823                        : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
 824                          "S"(child_stack),
 825                          "D"(flags),
 826                          "d"(parent_tidptr),
 827                          "r"(r8),
 828                          "r"(r10)
 829                        : "rsp", "memory", "r11", "rcx");
 830   return res;
 831 }
 832 #endif  // defined(__x86_64__) && SANITIZER_LINUX
 833
 834 #if SANITIZER_ANDROID
 835 static atomic_uint8_t android_log_initialized;
 836
 837 void AndroidLogInit() {
 838   atomic_store(&android_log_initialized, 1, memory_order_release);
 839 }
 840 // This thing is not, strictly speaking, async signal safe, but it does not seem
 841 // to cause any issues. Alternative is writing to log devices directly, but
 842 // their location and message format might change in the future, so we'd really
 843 // like to avoid that.
 844 void AndroidLogWrite(const char *buffer) {
 845   if (!atomic_load(&android_log_initialized, memory_order_acquire))
 846     return;
 847
 848   char *copy = internal_strdup(buffer);
 849   char *p = copy;
 850   char *q;
 851   // __android_log_write has an implicit message length limit.
 852   // Print one line at a time.
 853   do {
 854     q = internal_strchr(p, '\n');
 855     if (q) *q = '\0';
 856     __android_log_write(ANDROID_LOG_INFO, NULL, p);
 857     if (q) p = q + 1;
 858   } while (q);
 859   InternalFree(copy);
 860 }
 861
 862 void GetExtraActivationFlags(char *buf, uptr size) {
 863   CHECK(size > PROP_VALUE_MAX);
 864   __system_property_get("asan.options", buf);
 865 }
 866 #endif
 867
 868 bool IsDeadlySignal(int signum) {
 869   return (signum == SIGSEGV) && common_flags()->handle_segv;
 870 }
 871
 872 }  // namespace __sanitizer
 873
 874 #endif  // SANITIZER_FREEBSD || SANITIZER_LINUX