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 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 285   struct stat st;
 286   if (internal_syscall(SYSCALL(newfstatat), AT_FDCWD, filename, &st, 0))
 287     return false;
 288 #else
 289   struct stat st;
 290   if (internal_stat(filename, &st))
 291     return false;
 292   // Sanity check: filename is a regular file.
 293   return S_ISREG(st.st_mode);
 294 #endif
 295 }
 296
 297 uptr GetTid() {
 298 #if SANITIZER_FREEBSD
 299   return (uptr)pthread_self();
 300 #else
 301   return internal_syscall(SYSCALL(gettid));
 302 #endif
 303 }
 304
 305 u64 NanoTime() {
 306 #if SANITIZER_FREEBSD
 307   timeval tv;
 308 #else
 309   kernel_timeval tv;
 310 #endif
 311   internal_memset(&tv, 0, sizeof(tv));
 312   internal_syscall(SYSCALL(gettimeofday), (uptr)&tv, 0);
 313   return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000;
 314 }
 315
 316 // Like getenv, but reads env directly from /proc (on Linux) or parses the
 317 // 'environ' array (on FreeBSD) and does not use libc. This function should be
 318 // called first inside __asan_init.
 319 const char *GetEnv(const char *name) {
 320 #if SANITIZER_FREEBSD
 321   if (::environ != 0) {
 322     uptr NameLen = internal_strlen(name);
 323     for (char **Env = ::environ; *Env != 0; Env++) {
 324       if (internal_strncmp(*Env, name, NameLen) == 0 && (*Env)[NameLen] == '=')
 325         return (*Env) + NameLen + 1;
 326     }
 327   }
 328   return 0;  // Not found.
 329 #elif SANITIZER_LINUX
 330   static char *environ;
 331   static uptr len;
 332   static bool inited;
 333   if (!inited) {
 334     inited = true;
 335     uptr environ_size;
 336     len = ReadFileToBuffer("/proc/self/environ",
 337                            &environ, &environ_size, 1 << 26);
 338   }
 339   if (!environ || len == 0) return 0;
 340   uptr namelen = internal_strlen(name);
 341   const char *p = environ;
 342   while (*p != '\0') {  // will happen at the \0\0 that terminates the buffer
 343     // proc file has the format NAME=value\0NAME=value\0NAME=value\0...
 344     const char* endp =
 345         (char*)internal_memchr(p, '\0', len - (p - environ));
 346     if (endp == 0)  // this entry isn't NUL terminated
 347       return 0;
 348     else if (!internal_memcmp(p, name, namelen) && p[namelen] == '=')  // Match.
 349       return p + namelen + 1;  // point after =
 350     p = endp + 1;
 351   }
 352   return 0;  // Not found.
 353 #else
 354 #error "Unsupported platform"
 355 #endif
 356 }
 357
 358 extern "C" {
 359   SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end;
 360 }
 361
 362 #if !SANITIZER_GO
 363 static void ReadNullSepFileToArray(const char *path, char ***arr,
 364                                    int arr_size) {
 365   char *buff;
 366   uptr buff_size = 0;
 367   *arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray");
 368   ReadFileToBuffer(path, &buff, &buff_size, 1024 * 1024);
 369   (*arr)[0] = buff;
 370   int count, i;
 371   for (count = 1, i = 1; ; i++) {
 372     if (buff[i] == 0) {
 373       if (buff[i+1] == 0) break;
 374       (*arr)[count] = &buff[i+1];
 375       CHECK_LE(count, arr_size - 1);  // FIXME: make this more flexible.
 376       count++;
 377     }
 378   }
 379   (*arr)[count] = 0;
 380 }
 381 #endif
 382
 383 static void GetArgsAndEnv(char*** argv, char*** envp) {
 384 #if !SANITIZER_GO
 385   if (&__libc_stack_end) {
 386 #endif
 387     uptr* stack_end = (uptr*)__libc_stack_end;
 388     int argc = *stack_end;
 389     *argv = (char**)(stack_end + 1);
 390     *envp = (char**)(stack_end + argc + 2);
 391 #if !SANITIZER_GO
 392   } else {
 393     static const int kMaxArgv = 2000, kMaxEnvp = 2000;
 394     ReadNullSepFileToArray("/proc/self/cmdline", argv, kMaxArgv);
 395     ReadNullSepFileToArray("/proc/self/environ", envp, kMaxEnvp);
 396   }
 397 #endif
 398 }
 399
 400 void ReExec() {
 401   char **argv, **envp;
 402   GetArgsAndEnv(&argv, &envp);
 403   uptr rv = internal_execve("/proc/self/exe", argv, envp);
 404   int rverrno;
 405   CHECK_EQ(internal_iserror(rv, &rverrno), true);
 406   Printf("execve failed, errno %d\n", rverrno);
 407   Die();
 408 }
 409
 410 // Stub implementation of GetThreadStackAndTls for Go.
 411 #if SANITIZER_GO
 412 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
 413                           uptr *tls_addr, uptr *tls_size) {
 414   *stk_addr = 0;
 415   *stk_size = 0;
 416   *tls_addr = 0;
 417   *tls_size = 0;
 418 }
 419 #endif  // SANITIZER_GO
 420
 421 enum MutexState {
 422   MtxUnlocked = 0,
 423   MtxLocked = 1,
 424   MtxSleeping = 2
 425 };
 426
 427 BlockingMutex::BlockingMutex(LinkerInitialized) {
 428   CHECK_EQ(owner_, 0);
 429 }
 430
 431 BlockingMutex::BlockingMutex() {
 432   internal_memset(this, 0, sizeof(*this));
 433 }
 434
 435 void BlockingMutex::Lock() {
 436   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
 437   if (atomic_exchange(m, MtxLocked, memory_order_acquire) == MtxUnlocked)
 438     return;
 439   while (atomic_exchange(m, MtxSleeping, memory_order_acquire) != MtxUnlocked) {
 440 #if SANITIZER_FREEBSD
 441     _umtx_op(m, UMTX_OP_WAIT_UINT, MtxSleeping, 0, 0);
 442 #else
 443     internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAIT, MtxSleeping, 0, 0, 0);
 444 #endif
 445   }
 446 }
 447
 448 void BlockingMutex::Unlock() {
 449   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
 450   u32 v = atomic_exchange(m, MtxUnlocked, memory_order_relaxed);
 451   CHECK_NE(v, MtxUnlocked);
 452   if (v == MtxSleeping) {
 453 #if SANITIZER_FREEBSD
 454     _umtx_op(m, UMTX_OP_WAKE, 1, 0, 0);
 455 #else
 456     internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAKE, 1, 0, 0, 0);
 457 #endif
 458   }
 459 }
 460
 461 void BlockingMutex::CheckLocked() {
 462   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
 463   CHECK_NE(MtxUnlocked, atomic_load(m, memory_order_relaxed));
 464 }
 465
 466 // ----------------- sanitizer_linux.h
 467 // The actual size of this structure is specified by d_reclen.
 468 // Note that getdents64 uses a different structure format. We only provide the
 469 // 32-bit syscall here.
 470 struct linux_dirent {
 471 #if SANITIZER_X32
 472   u64 d_ino;
 473   u64 d_off;
 474 #else
 475   unsigned long      d_ino;
 476   unsigned long      d_off;
 477 #endif
 478   unsigned short     d_reclen;
 479   char               d_name[256];
 480 };
 481
 482 // Syscall wrappers.
 483 uptr internal_ptrace(int request, int pid, void *addr, void *data) {
 484   return internal_syscall(SYSCALL(ptrace), request, pid, (uptr)addr,
 485                           (uptr)data);
 486 }
 487
 488 uptr internal_waitpid(int pid, int *status, int options) {
 489   return internal_syscall(SYSCALL(wait4), pid, (uptr)status, options,
 490                           0 /* rusage */);
 491 }
 492
 493 uptr internal_getpid() {
 494   return internal_syscall(SYSCALL(getpid));
 495 }
 496
 497 uptr internal_getppid() {
 498   return internal_syscall(SYSCALL(getppid));
 499 }
 500
 501 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) {
 502 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 503   return internal_syscall(SYSCALL(getdents64), fd, (uptr)dirp, count);
 504 #else
 505   return internal_syscall(SYSCALL(getdents), fd, (uptr)dirp, count);
 506 #endif
 507 }
 508
 509 uptr internal_lseek(fd_t fd, OFF_T offset, int whence) {
 510   return internal_syscall(SYSCALL(lseek), fd, offset, whence);
 511 }
 512
 513 #if SANITIZER_LINUX
 514 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) {
 515   return internal_syscall(SYSCALL(prctl), option, arg2, arg3, arg4, arg5);
 516 }
 517 #endif
 518
 519 uptr internal_sigaltstack(const struct sigaltstack *ss,
 520                          struct sigaltstack *oss) {
 521   return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
 522 }
 523
 524 int internal_fork() {
 525 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 526   return internal_syscall(SYSCALL(clone), SIGCHLD, 0);
 527 #else
 528   return internal_syscall(SYSCALL(fork));
 529 #endif
 530 }
 531
 532 #if SANITIZER_LINUX
 533 // Doesn't set sa_restorer, use with caution (see below).
 534 int internal_sigaction_norestorer(int signum, const void *act, void *oldact) {
 535   __sanitizer_kernel_sigaction_t k_act, k_oldact;
 536   internal_memset(&k_act, 0, sizeof(__sanitizer_kernel_sigaction_t));
 537   internal_memset(&k_oldact, 0, sizeof(__sanitizer_kernel_sigaction_t));
 538   const __sanitizer_sigaction *u_act = (__sanitizer_sigaction *)act;
 539   __sanitizer_sigaction *u_oldact = (__sanitizer_sigaction *)oldact;
 540   if (u_act) {
 541     k_act.handler = u_act->handler;
 542     k_act.sigaction = u_act->sigaction;
 543     internal_memcpy(&k_act.sa_mask, &u_act->sa_mask,
 544                     sizeof(__sanitizer_kernel_sigset_t));
 545     k_act.sa_flags = u_act->sa_flags;
 546     // FIXME: most often sa_restorer is unset, however the kernel requires it
 547     // to point to a valid signal restorer that calls the rt_sigreturn syscall.
 548     // If sa_restorer passed to the kernel is NULL, the program may crash upon
 549     // signal delivery or fail to unwind the stack in the signal handler.
 550     // libc implementation of sigaction() passes its own restorer to
 551     // rt_sigaction, so we need to do the same (we'll need to reimplement the
 552     // restorers; for x86_64 the restorer address can be obtained from
 553     // oldact->sa_restorer upon a call to sigaction(xxx, NULL, oldact).
 554     k_act.sa_restorer = u_act->sa_restorer;
 555   }
 556
 557   uptr result = internal_syscall(SYSCALL(rt_sigaction), (uptr)signum,
 558       (uptr)(u_act ? &k_act : NULL),
 559       (uptr)(u_oldact ? &k_oldact : NULL),
 560       (uptr)sizeof(__sanitizer_kernel_sigset_t));
 561
 562   if ((result == 0) && u_oldact) {
 563     u_oldact->handler = k_oldact.handler;
 564     u_oldact->sigaction = k_oldact.sigaction;
 565     internal_memcpy(&u_oldact->sa_mask, &k_oldact.sa_mask,
 566                     sizeof(__sanitizer_kernel_sigset_t));
 567     u_oldact->sa_flags = k_oldact.sa_flags;
 568     u_oldact->sa_restorer = k_oldact.sa_restorer;
 569   }
 570   return result;
 571 }
 572 #endif  // SANITIZER_LINUX
 573
 574 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
 575     __sanitizer_sigset_t *oldset) {
 576 #if SANITIZER_FREEBSD
 577   return internal_syscall(SYSCALL(sigprocmask), how, set, oldset);
 578 #else
 579   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
 580   __sanitizer_kernel_sigset_t *k_oldset = (__sanitizer_kernel_sigset_t *)oldset;
 581   return internal_syscall(SYSCALL(rt_sigprocmask), (uptr)how,
 582                           (uptr)&k_set->sig[0], (uptr)&k_oldset->sig[0],
 583                           sizeof(__sanitizer_kernel_sigset_t));
 584 #endif
 585 }
 586
 587 void internal_sigfillset(__sanitizer_sigset_t *set) {
 588   internal_memset(set, 0xff, sizeof(*set));
 589 }
 590
 591 #if SANITIZER_LINUX
 592 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
 593   signum -= 1;
 594   CHECK_GE(signum, 0);
 595   CHECK_LT(signum, sizeof(*set) * 8);
 596   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
 597   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
 598   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
 599   k_set->sig[idx] &= ~(1 << bit);
 600 }
 601 #endif  // SANITIZER_LINUX
 602
 603 // ThreadLister implementation.
 604 ThreadLister::ThreadLister(int pid)
 605   : pid_(pid),
 606     descriptor_(-1),
 607     buffer_(4096),
 608     error_(true),
 609     entry_((struct linux_dirent *)buffer_.data()),
 610     bytes_read_(0) {
 611   char task_directory_path[80];
 612   internal_snprintf(task_directory_path, sizeof(task_directory_path),
 613                     "/proc/%d/task/", pid);
 614   uptr openrv = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY);
 615   if (internal_iserror(openrv)) {
 616     error_ = true;
 617     Report("Can't open /proc/%d/task for reading.\n", pid);
 618   } else {
 619     error_ = false;
 620     descriptor_ = openrv;
 621   }
 622 }
 623
 624 int ThreadLister::GetNextTID() {
 625   int tid = -1;
 626   do {
 627     if (error_)
 628       return -1;
 629     if ((char *)entry_ >= &buffer_[bytes_read_] && !GetDirectoryEntries())
 630       return -1;
 631     if (entry_->d_ino != 0 && entry_->d_name[0] >= '0' &&
 632         entry_->d_name[0] <= '9') {
 633       // Found a valid tid.
 634       tid = (int)internal_atoll(entry_->d_name);
 635     }
 636     entry_ = (struct linux_dirent *)(((char *)entry_) + entry_->d_reclen);
 637   } while (tid < 0);
 638   return tid;
 639 }
 640
 641 void ThreadLister::Reset() {
 642   if (error_ || descriptor_ < 0)
 643     return;
 644   internal_lseek(descriptor_, 0, SEEK_SET);
 645 }
 646
 647 ThreadLister::~ThreadLister() {
 648   if (descriptor_ >= 0)
 649     internal_close(descriptor_);
 650 }
 651
 652 bool ThreadLister::error() { return error_; }
 653
 654 bool ThreadLister::GetDirectoryEntries() {
 655   CHECK_GE(descriptor_, 0);
 656   CHECK_NE(error_, true);
 657   bytes_read_ = internal_getdents(descriptor_,
 658                                   (struct linux_dirent *)buffer_.data(),
 659                                   buffer_.size());
 660   if (internal_iserror(bytes_read_)) {
 661     Report("Can't read directory entries from /proc/%d/task.\n", pid_);
 662     error_ = true;
 663     return false;
 664   } else if (bytes_read_ == 0) {
 665     return false;
 666   }
 667   entry_ = (struct linux_dirent *)buffer_.data();
 668   return true;
 669 }
 670
 671 uptr GetPageSize() {
 672 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__))
 673   return EXEC_PAGESIZE;
 674 #else
 675   return sysconf(_SC_PAGESIZE);  // EXEC_PAGESIZE may not be trustworthy.
 676 #endif
 677 }
 678
 679 static char proc_self_exe_cache_str[kMaxPathLength];
 680 static uptr proc_self_exe_cache_len = 0;
 681
 682 uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
 683   if (proc_self_exe_cache_len > 0) {
 684     // If available, use the cached module name.
 685     uptr module_name_len =
 686         internal_snprintf(buf, buf_len, "%s", proc_self_exe_cache_str);
 687     CHECK_LT(module_name_len, buf_len);
 688     return module_name_len;
 689   }
 690 #if SANITIZER_FREEBSD
 691   const int Mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1 };
 692   size_t Size = buf_len;
 693   bool IsErr = (sysctl(Mib, 4, buf, &Size, NULL, 0) != 0);
 694   int readlink_error = IsErr ? errno : 0;
 695   uptr module_name_len = Size;
 696 #else
 697   uptr module_name_len = internal_readlink(
 698       "/proc/self/exe", buf, buf_len);
 699   int readlink_error;
 700   bool IsErr = internal_iserror(module_name_len, &readlink_error);
 701 #endif
 702   if (IsErr) {
 703     // We can't read /proc/self/exe for some reason, assume the name of the
 704     // binary is unknown.
 705     Report("WARNING: readlink(\"/proc/self/exe\") failed with errno %d, "
 706            "some stack frames may not be symbolized\n", readlink_error);
 707     module_name_len = internal_snprintf(buf, buf_len, "/proc/self/exe");
 708     CHECK_LT(module_name_len, buf_len);
 709   }
 710   return module_name_len;
 711 }
 712
 713 void CacheBinaryName() {
 714   if (!proc_self_exe_cache_len) {
 715     proc_self_exe_cache_len =
 716         ReadBinaryName(proc_self_exe_cache_str, kMaxPathLength);
 717   }
 718 }
 719
 720 // Match full names of the form /path/to/base_name{-,.}*
 721 bool LibraryNameIs(const char *full_name, const char *base_name) {
 722   const char *name = full_name;
 723   // Strip path.
 724   while (*name != '\0') name++;
 725   while (name > full_name && *name != '/') name--;
 726   if (*name == '/') name++;
 727   uptr base_name_length = internal_strlen(base_name);
 728   if (internal_strncmp(name, base_name, base_name_length)) return false;
 729   return (name[base_name_length] == '-' || name[base_name_length] == '.');
 730 }
 731
 732 #if !SANITIZER_ANDROID
 733 // Call cb for each region mapped by map.
 734 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) {
 735 #if !SANITIZER_FREEBSD
 736   typedef ElfW(Phdr) Elf_Phdr;
 737   typedef ElfW(Ehdr) Elf_Ehdr;
 738 #endif  // !SANITIZER_FREEBSD
 739   char *base = (char *)map->l_addr;
 740   Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
 741   char *phdrs = base + ehdr->e_phoff;
 742   char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize;
 743
 744   // Find the segment with the minimum base so we can "relocate" the p_vaddr
 745   // fields.  Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC
 746   // objects have a non-zero base.
 747   uptr preferred_base = (uptr)-1;
 748   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
 749     Elf_Phdr *phdr = (Elf_Phdr *)iter;
 750     if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr)
 751       preferred_base = (uptr)phdr->p_vaddr;
 752   }
 753
 754   // Compute the delta from the real base to get a relocation delta.
 755   sptr delta = (uptr)base - preferred_base;
 756   // Now we can figure out what the loader really mapped.
 757   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
 758     Elf_Phdr *phdr = (Elf_Phdr *)iter;
 759     if (phdr->p_type == PT_LOAD) {
 760       uptr seg_start = phdr->p_vaddr + delta;
 761       uptr seg_end = seg_start + phdr->p_memsz;
 762       // None of these values are aligned.  We consider the ragged edges of the
 763       // load command as defined, since they are mapped from the file.
 764       seg_start = RoundDownTo(seg_start, GetPageSizeCached());
 765       seg_end = RoundUpTo(seg_end, GetPageSizeCached());
 766       cb((void *)seg_start, seg_end - seg_start);
 767     }
 768   }
 769 }
 770 #endif
 771
 772 #if defined(__x86_64__) && SANITIZER_LINUX
 773 // We cannot use glibc's clone wrapper, because it messes with the child
 774 // task's TLS. It writes the PID and TID of the child task to its thread
 775 // descriptor, but in our case the child task shares the thread descriptor with
 776 // the parent (because we don't know how to allocate a new thread
 777 // descriptor to keep glibc happy). So the stock version of clone(), when
 778 // used with CLONE_VM, would end up corrupting the parent's thread descriptor.
 779 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
 780                     int *parent_tidptr, void *newtls, int *child_tidptr) {
 781   long long res;
 782   if (!fn || !child_stack)
 783     return -EINVAL;
 784   CHECK_EQ(0, (uptr)child_stack % 16);
 785   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
 786   ((unsigned long long *)child_stack)[0] = (uptr)fn;
 787   ((unsigned long long *)child_stack)[1] = (uptr)arg;
 788   register void *r8 __asm__("r8") = newtls;
 789   register int *r10 __asm__("r10") = child_tidptr;
 790   __asm__ __volatile__(
 791                        /* %rax = syscall(%rax = SYSCALL(clone),
 792                         *                %rdi = flags,
 793                         *                %rsi = child_stack,
 794                         *                %rdx = parent_tidptr,
 795                         *                %r8  = new_tls,
 796                         *                %r10 = child_tidptr)
 797                         */
 798                        "syscall\n"
 799
 800                        /* if (%rax != 0)
 801                         *   return;
 802                         */
 803                        "testq  %%rax,%%rax\n"
 804                        "jnz    1f\n"
 805
 806                        /* In the child. Terminate unwind chain. */
 807                        // XXX: We should also terminate the CFI unwind chain
 808                        // here. Unfortunately clang 3.2 doesn't support the
 809                        // necessary CFI directives, so we skip that part.
 810                        "xorq   %%rbp,%%rbp\n"
 811
 812                        /* Call "fn(arg)". */
 813                        "popq   %%rax\n"
 814                        "popq   %%rdi\n"
 815                        "call   *%%rax\n"
 816
 817                        /* Call _exit(%rax). */
 818                        "movq   %%rax,%%rdi\n"
 819                        "movq   %2,%%rax\n"
 820                        "syscall\n"
 821
 822                        /* Return to parent. */
 823                      "1:\n"
 824                        : "=a" (res)
 825                        : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
 826                          "S"(child_stack),
 827                          "D"(flags),
 828                          "d"(parent_tidptr),
 829                          "r"(r8),
 830                          "r"(r10)
 831                        : "rsp", "memory", "r11", "rcx");
 832   return res;
 833 }
 834 #endif  // defined(__x86_64__) && SANITIZER_LINUX
 835
 836 #if SANITIZER_ANDROID
 837 static atomic_uint8_t android_log_initialized;
 838
 839 void AndroidLogInit() {
 840   atomic_store(&android_log_initialized, 1, memory_order_release);
 841 }
 842 // This thing is not, strictly speaking, async signal safe, but it does not seem
 843 // to cause any issues. Alternative is writing to log devices directly, but
 844 // their location and message format might change in the future, so we'd really
 845 // like to avoid that.
 846 void AndroidLogWrite(const char *buffer) {
 847   if (!atomic_load(&android_log_initialized, memory_order_acquire))
 848     return;
 849
 850   char *copy = internal_strdup(buffer);
 851   char *p = copy;
 852   char *q;
 853   // __android_log_write has an implicit message length limit.
 854   // Print one line at a time.
 855   do {
 856     q = internal_strchr(p, '\n');
 857     if (q) *q = '\0';
 858     __android_log_write(ANDROID_LOG_INFO, NULL, p);
 859     if (q) p = q + 1;
 860   } while (q);
 861   InternalFree(copy);
 862 }
 863
 864 void GetExtraActivationFlags(char *buf, uptr size) {
 865   CHECK(size > PROP_VALUE_MAX);
 866   __system_property_get("asan.options", buf);
 867 }
 868 #endif
 869
 870 bool IsDeadlySignal(int signum) {
 871   return (signum == SIGSEGV) && common_flags()->handle_segv;
 872 }
 873
 874 }  // namespace __sanitizer
 875
 876 #endif  // SANITIZER_FREEBSD || SANITIZER_LINUX