lib/sanitizer_common/sanitizer_linux.cc

   1 //===-- sanitizer_linux.cc ------------------------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file is shared between AddressSanitizer and ThreadSanitizer
  11 // run-time libraries and implements linux-specific functions from
  12 // sanitizer_libc.h.
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "sanitizer_platform.h"
  16 #if SANITIZER_FREEBSD || SANITIZER_LINUX
  17
  18 #include "sanitizer_common.h"
  19 #include "sanitizer_flags.h"
  20 #include "sanitizer_internal_defs.h"
  21 #include "sanitizer_libc.h"
  22 #include "sanitizer_linux.h"
  23 #include "sanitizer_mutex.h"
  24 #include "sanitizer_placement_new.h"
  25 #include "sanitizer_procmaps.h"
  26 #include "sanitizer_stacktrace.h"
  27 #include "sanitizer_symbolizer.h"
  28
  29 #if !SANITIZER_FREEBSD
  30 #include <asm/param.h>
  31 #endif
  32
  33 #include <dlfcn.h>
  34 #include <errno.h>
  35 #include <fcntl.h>
  36 #if !SANITIZER_ANDROID
  37 #include <link.h>
  38 #endif
  39 #include <pthread.h>
  40 #include <sched.h>
  41 #include <sys/mman.h>
  42 #include <sys/ptrace.h>
  43 #include <sys/resource.h>
  44 #include <sys/stat.h>
  45 #include <sys/syscall.h>
  46 #include <sys/time.h>
  47 #include <sys/types.h>
  48 #include <unistd.h>
  49
  50 #if SANITIZER_FREEBSD
  51 #include <sys/sysctl.h>
  52 #include <machine/atomic.h>
  53 extern "C" {
  54 // <sys/umtx.h> must be included after <errno.h> and <sys/types.h> on
  55 // FreeBSD 9.2 and 10.0.
  56 #include <sys/umtx.h>
  57 }
  58 extern char **environ;  // provided by crt1
  59 #endif  // SANITIZER_FREEBSD
  60
  61 #if !SANITIZER_ANDROID
  62 #include <sys/signal.h>
  63 #endif
  64
  65 #if SANITIZER_ANDROID
  66 #include <android/log.h>
  67 #include <sys/system_properties.h>
  68 #endif
  69
  70 #if SANITIZER_LINUX
  71 // <linux/time.h>
  72 struct kernel_timeval {
  73   long tv_sec;
  74   long tv_usec;
  75 };
  76
  77 // <linux/futex.h> is broken on some linux distributions.
  78 const int FUTEX_WAIT = 0;
  79 const int FUTEX_WAKE = 1;
  80 #endif  // SANITIZER_LINUX
  81
  82 // Are we using 32-bit or 64-bit Linux syscalls?
  83 // x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 32
  84 // but it still needs to use 64-bit syscalls.
  85 #if SANITIZER_LINUX && (defined(__x86_64__) || SANITIZER_WORDSIZE == 64)
  86 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 1
  87 #else
  88 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 0
  89 #endif
  90
  91 namespace __sanitizer {
  92
  93 #if SANITIZER_LINUX && defined(__x86_64__)
  94 #include "sanitizer_syscall_linux_x86_64.inc"
  95 #else
  96 #include "sanitizer_syscall_generic.inc"
  97 #endif
  98
  99 // --------------- sanitizer_libc.h
 100 uptr internal_mmap(void *addr, uptr length, int prot, int flags,
 101                     int fd, u64 offset) {
 102 #if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
 103   return internal_syscall(SYSCALL(mmap), (uptr)addr, length, prot, flags, fd,
 104                           offset);
 105 #else
 106   return internal_syscall(SYSCALL(mmap2), addr, length, prot, flags, fd,
 107                           offset);
 108 #endif
 109 }
 110
 111 uptr internal_munmap(void *addr, uptr length) {
 112   return internal_syscall(SYSCALL(munmap), (uptr)addr, length);
 113 }
 114
 115 uptr internal_close(fd_t fd) {
 116   return internal_syscall(SYSCALL(close), fd);
 117 }
 118
 119 uptr internal_open(const char *filename, int flags) {
 120 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 121   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags);
 122 #else
 123   return internal_syscall(SYSCALL(open), (uptr)filename, flags);
 124 #endif
 125 }
 126
 127 uptr internal_open(const char *filename, int flags, u32 mode) {
 128 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 129   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags,
 130                           mode);
 131 #else
 132   return internal_syscall(SYSCALL(open), (uptr)filename, flags, mode);
 133 #endif
 134 }
 135
 136 uptr OpenFile(const char *filename, bool write) {
 137   return internal_open(filename,
 138       write ? O_RDWR | O_CREAT /*| O_CLOEXEC*/ : O_RDONLY, 0660);
 139 }
 140
 141 uptr internal_read(fd_t fd, void *buf, uptr count) {
 142   sptr res;
 143   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(read), fd, (uptr)buf,
 144                count));
 145   return res;
 146 }
 147
 148 uptr internal_write(fd_t fd, const void *buf, uptr count) {
 149   sptr res;
 150   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(write), fd, (uptr)buf,
 151                count));
 152   return res;
 153 }
 154
 155 uptr internal_ftruncate(fd_t fd, uptr size) {
 156   sptr res;
 157   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(ftruncate), fd, size));
 158   return res;
 159 }
 160
 161 #if !SANITIZER_LINUX_USES_64BIT_SYSCALLS && !SANITIZER_FREEBSD
 162 static void stat64_to_stat(struct stat64 *in, struct stat *out) {
 163   internal_memset(out, 0, sizeof(*out));
 164   out->st_dev = in->st_dev;
 165   out->st_ino = in->st_ino;
 166   out->st_mode = in->st_mode;
 167   out->st_nlink = in->st_nlink;
 168   out->st_uid = in->st_uid;
 169   out->st_gid = in->st_gid;
 170   out->st_rdev = in->st_rdev;
 171   out->st_size = in->st_size;
 172   out->st_blksize = in->st_blksize;
 173   out->st_blocks = in->st_blocks;
 174   out->st_atime = in->st_atime;
 175   out->st_mtime = in->st_mtime;
 176   out->st_ctime = in->st_ctime;
 177   out->st_ino = in->st_ino;
 178 }
 179 #endif
 180
 181 uptr internal_stat(const char *path, void *buf) {
 182 #if SANITIZER_FREEBSD
 183   return internal_syscall(SYSCALL(stat), path, buf);
 184 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 185   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path,
 186                           (uptr)buf, 0);
 187 #elif SANITIZER_LINUX_USES_64BIT_SYSCALLS
 188   return internal_syscall(SYSCALL(stat), (uptr)path, (uptr)buf);
 189 #else
 190   struct stat64 buf64;
 191   int res = internal_syscall(SYSCALL(stat64), path, &buf64);
 192   stat64_to_stat(&buf64, (struct stat *)buf);
 193   return res;
 194 #endif
 195 }
 196
 197 uptr internal_lstat(const char *path, void *buf) {
 198 #if SANITIZER_FREEBSD
 199   return internal_syscall(SYSCALL(lstat), path, buf);
 200 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 201   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path,
 202                          (uptr)buf, AT_SYMLINK_NOFOLLOW);
 203 #elif SANITIZER_LINUX_USES_64BIT_SYSCALLS
 204   return internal_syscall(SYSCALL(lstat), (uptr)path, (uptr)buf);
 205 #else
 206   struct stat64 buf64;
 207   int res = internal_syscall(SYSCALL(lstat64), path, &buf64);
 208   stat64_to_stat(&buf64, (struct stat *)buf);
 209   return res;
 210 #endif
 211 }
 212
 213 uptr internal_fstat(fd_t fd, void *buf) {
 214 #if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
 215   return internal_syscall(SYSCALL(fstat), fd, (uptr)buf);
 216 #else
 217   struct stat64 buf64;
 218   int res = internal_syscall(SYSCALL(fstat64), fd, &buf64);
 219   stat64_to_stat(&buf64, (struct stat *)buf);
 220   return res;
 221 #endif
 222 }
 223
 224 uptr internal_filesize(fd_t fd) {
 225   struct stat st;
 226   if (internal_fstat(fd, &st))
 227     return -1;
 228   return (uptr)st.st_size;
 229 }
 230
 231 uptr internal_dup2(int oldfd, int newfd) {
 232 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 233   return internal_syscall(SYSCALL(dup3), oldfd, newfd, 0);
 234 #else
 235   return internal_syscall(SYSCALL(dup2), oldfd, newfd);
 236 #endif
 237 }
 238
 239 uptr internal_readlink(const char *path, char *buf, uptr bufsize) {
 240 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 241   return internal_syscall(SYSCALL(readlinkat), AT_FDCWD,
 242                           (uptr)path, (uptr)buf, bufsize);
 243 #else
 244   return internal_syscall(SYSCALL(readlink), (uptr)path, (uptr)buf, bufsize);
 245 #endif
 246 }
 247
 248 uptr internal_unlink(const char *path) {
 249 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 250   return internal_syscall(SYSCALL(unlinkat), AT_FDCWD, (uptr)path, 0);
 251 #else
 252   return internal_syscall(SYSCALL(unlink), (uptr)path);
 253 #endif
 254 }
 255
 256 uptr internal_rename(const char *oldpath, const char *newpath) {
 257 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 258   return internal_syscall(SYSCALL(renameat), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
 259                           (uptr)newpath);
 260 #else
 261   return internal_syscall(SYSCALL(rename), (uptr)oldpath, (uptr)newpath);
 262 #endif
 263 }
 264
 265 uptr internal_sched_yield() {
 266   return internal_syscall(SYSCALL(sched_yield));
 267 }
 268
 269 void internal__exit(int exitcode) {
 270 #if SANITIZER_FREEBSD
 271   internal_syscall(SYSCALL(exit), exitcode);
 272 #else
 273   internal_syscall(SYSCALL(exit_group), exitcode);
 274 #endif
 275   Die();  // Unreachable.
 276 }
 277
 278 uptr internal_execve(const char *filename, char *const argv[],
 279                      char *const envp[]) {
 280   return internal_syscall(SYSCALL(execve), (uptr)filename, (uptr)argv,
 281                           (uptr)envp);
 282 }
 283
 284 // ----------------- sanitizer_common.h
 285 bool FileExists(const char *filename) {
 286 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 287   struct stat st;
 288   if (internal_syscall(SYSCALL(newfstatat), AT_FDCWD, filename, &st, 0))
 289     return false;
 290 #else
 291   struct stat st;
 292   if (internal_stat(filename, &st))
 293     return false;
 294   // Sanity check: filename is a regular file.
 295   return S_ISREG(st.st_mode);
 296 #endif
 297 }
 298
 299 uptr GetTid() {
 300 #if SANITIZER_FREEBSD
 301   return (uptr)pthread_self();
 302 #else
 303   return internal_syscall(SYSCALL(gettid));
 304 #endif
 305 }
 306
 307 u64 NanoTime() {
 308 #if SANITIZER_FREEBSD
 309   timeval tv;
 310 #else
 311   kernel_timeval tv;
 312 #endif
 313   internal_memset(&tv, 0, sizeof(tv));
 314   internal_syscall(SYSCALL(gettimeofday), (uptr)&tv, 0);
 315   return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000;
 316 }
 317
 318 // Like getenv, but reads env directly from /proc (on Linux) or parses the
 319 // 'environ' array (on FreeBSD) and does not use libc. This function should be
 320 // called first inside __asan_init.
 321 const char *GetEnv(const char *name) {
 322 #if SANITIZER_FREEBSD
 323   if (::environ != 0) {
 324     uptr NameLen = internal_strlen(name);
 325     for (char **Env = ::environ; *Env != 0; Env++) {
 326       if (internal_strncmp(*Env, name, NameLen) == 0 && (*Env)[NameLen] == '=')
 327         return (*Env) + NameLen + 1;
 328     }
 329   }
 330   return 0;  // Not found.
 331 #elif SANITIZER_LINUX
 332   static char *environ;
 333   static uptr len;
 334   static bool inited;
 335   if (!inited) {
 336     inited = true;
 337     uptr environ_size;
 338     len = ReadFileToBuffer("/proc/self/environ",
 339                            &environ, &environ_size, 1 << 26);
 340   }
 341   if (!environ || len == 0) return 0;
 342   uptr namelen = internal_strlen(name);
 343   const char *p = environ;
 344   while (*p != '\0') {  // will happen at the \0\0 that terminates the buffer
 345     // proc file has the format NAME=value\0NAME=value\0NAME=value\0...
 346     const char* endp =
 347         (char*)internal_memchr(p, '\0', len - (p - environ));
 348     if (endp == 0)  // this entry isn't NUL terminated
 349       return 0;
 350     else if (!internal_memcmp(p, name, namelen) && p[namelen] == '=')  // Match.
 351       return p + namelen + 1;  // point after =
 352     p = endp + 1;
 353   }
 354   return 0;  // Not found.
 355 #else
 356 #error "Unsupported platform"
 357 #endif
 358 }
 359
 360 extern "C" {
 361   SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end;
 362 }
 363
 364 #if !SANITIZER_GO
 365 static void ReadNullSepFileToArray(const char *path, char ***arr,
 366                                    int arr_size) {
 367   char *buff;
 368   uptr buff_size = 0;
 369   *arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray");
 370   ReadFileToBuffer(path, &buff, &buff_size, 1024 * 1024);
 371   (*arr)[0] = buff;
 372   int count, i;
 373   for (count = 1, i = 1; ; i++) {
 374     if (buff[i] == 0) {
 375       if (buff[i+1] == 0) break;
 376       (*arr)[count] = &buff[i+1];
 377       CHECK_LE(count, arr_size - 1);  // FIXME: make this more flexible.
 378       count++;
 379     }
 380   }
 381   (*arr)[count] = 0;
 382 }
 383 #endif
 384
 385 static void GetArgsAndEnv(char*** argv, char*** envp) {
 386 #if !SANITIZER_GO
 387   if (&__libc_stack_end) {
 388 #endif
 389     uptr* stack_end = (uptr*)__libc_stack_end;
 390     int argc = *stack_end;
 391     *argv = (char**)(stack_end + 1);
 392     *envp = (char**)(stack_end + argc + 2);
 393 #if !SANITIZER_GO
 394   } else {
 395     static const int kMaxArgv = 2000, kMaxEnvp = 2000;
 396     ReadNullSepFileToArray("/proc/self/cmdline", argv, kMaxArgv);
 397     ReadNullSepFileToArray("/proc/self/environ", envp, kMaxEnvp);
 398   }
 399 #endif
 400 }
 401
 402 void ReExec() {
 403   char **argv, **envp;
 404   GetArgsAndEnv(&argv, &envp);
 405   uptr rv = internal_execve("/proc/self/exe", argv, envp);
 406   int rverrno;
 407   CHECK_EQ(internal_iserror(rv, &rverrno), true);
 408   Printf("execve failed, errno %d\n", rverrno);
 409   Die();
 410 }
 411
 412 // Stub implementation of GetThreadStackAndTls for Go.
 413 #if SANITIZER_GO
 414 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
 415                           uptr *tls_addr, uptr *tls_size) {
 416   *stk_addr = 0;
 417   *stk_size = 0;
 418   *tls_addr = 0;
 419   *tls_size = 0;
 420 }
 421 #endif  // SANITIZER_GO
 422
 423 enum MutexState {
 424   MtxUnlocked = 0,
 425   MtxLocked = 1,
 426   MtxSleeping = 2
 427 };
 428
 429 BlockingMutex::BlockingMutex(LinkerInitialized) {
 430   CHECK_EQ(owner_, 0);
 431 }
 432
 433 BlockingMutex::BlockingMutex() {
 434   internal_memset(this, 0, sizeof(*this));
 435 }
 436
 437 void BlockingMutex::Lock() {
 438   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
 439   if (atomic_exchange(m, MtxLocked, memory_order_acquire) == MtxUnlocked)
 440     return;
 441   while (atomic_exchange(m, MtxSleeping, memory_order_acquire) != MtxUnlocked) {
 442 #if SANITIZER_FREEBSD
 443     _umtx_op(m, UMTX_OP_WAIT_UINT, MtxSleeping, 0, 0);
 444 #else
 445     internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAIT, MtxSleeping, 0, 0, 0);
 446 #endif
 447   }
 448 }
 449
 450 void BlockingMutex::Unlock() {
 451   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
 452   u32 v = atomic_exchange(m, MtxUnlocked, memory_order_relaxed);
 453   CHECK_NE(v, MtxUnlocked);
 454   if (v == MtxSleeping) {
 455 #if SANITIZER_FREEBSD
 456     _umtx_op(m, UMTX_OP_WAKE, 1, 0, 0);
 457 #else
 458     internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAKE, 1, 0, 0, 0);
 459 #endif
 460   }
 461 }
 462
 463 void BlockingMutex::CheckLocked() {
 464   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
 465   CHECK_NE(MtxUnlocked, atomic_load(m, memory_order_relaxed));
 466 }
 467
 468 // ----------------- sanitizer_linux.h
 469 // The actual size of this structure is specified by d_reclen.
 470 // Note that getdents64 uses a different structure format. We only provide the
 471 // 32-bit syscall here.
 472 struct linux_dirent {
 473 #if SANITIZER_X32
 474   u64 d_ino;
 475   u64 d_off;
 476 #else
 477   unsigned long      d_ino;
 478   unsigned long      d_off;
 479 #endif
 480   unsigned short     d_reclen;
 481   char               d_name[256];
 482 };
 483
 484 // Syscall wrappers.
 485 uptr internal_ptrace(int request, int pid, void *addr, void *data) {
 486   return internal_syscall(SYSCALL(ptrace), request, pid, (uptr)addr,
 487                           (uptr)data);
 488 }
 489
 490 uptr internal_waitpid(int pid, int *status, int options) {
 491   return internal_syscall(SYSCALL(wait4), pid, (uptr)status, options,
 492                           0 /* rusage */);
 493 }
 494
 495 uptr internal_getpid() {
 496   return internal_syscall(SYSCALL(getpid));
 497 }
 498
 499 uptr internal_getppid() {
 500   return internal_syscall(SYSCALL(getppid));
 501 }
 502
 503 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) {
 504 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 505   return internal_syscall(SYSCALL(getdents64), fd, (uptr)dirp, count);
 506 #else
 507   return internal_syscall(SYSCALL(getdents), fd, (uptr)dirp, count);
 508 #endif
 509 }
 510
 511 uptr internal_lseek(fd_t fd, OFF_T offset, int whence) {
 512   return internal_syscall(SYSCALL(lseek), fd, offset, whence);
 513 }
 514
 515 #if SANITIZER_LINUX
 516 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) {
 517   return internal_syscall(SYSCALL(prctl), option, arg2, arg3, arg4, arg5);
 518 }
 519 #endif
 520
 521 uptr internal_sigaltstack(const struct sigaltstack *ss,
 522                          struct sigaltstack *oss) {
 523   return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
 524 }
 525
 526 int internal_fork() {
 527 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
 528   return internal_syscall(SYSCALL(clone), SIGCHLD, 0);
 529 #else
 530   return internal_syscall(SYSCALL(fork));
 531 #endif
 532 }
 533
 534 #if SANITIZER_LINUX
 535 // Doesn't set sa_restorer, use with caution (see below).
 536 int internal_sigaction_norestorer(int signum, const void *act, void *oldact) {
 537   __sanitizer_kernel_sigaction_t k_act, k_oldact;
 538   internal_memset(&k_act, 0, sizeof(__sanitizer_kernel_sigaction_t));
 539   internal_memset(&k_oldact, 0, sizeof(__sanitizer_kernel_sigaction_t));
 540   const __sanitizer_sigaction *u_act = (__sanitizer_sigaction *)act;
 541   __sanitizer_sigaction *u_oldact = (__sanitizer_sigaction *)oldact;
 542   if (u_act) {
 543     k_act.handler = u_act->handler;
 544     k_act.sigaction = u_act->sigaction;
 545     internal_memcpy(&k_act.sa_mask, &u_act->sa_mask,
 546                     sizeof(__sanitizer_kernel_sigset_t));
 547     k_act.sa_flags = u_act->sa_flags;
 548     // FIXME: most often sa_restorer is unset, however the kernel requires it
 549     // to point to a valid signal restorer that calls the rt_sigreturn syscall.
 550     // If sa_restorer passed to the kernel is NULL, the program may crash upon
 551     // signal delivery or fail to unwind the stack in the signal handler.
 552     // libc implementation of sigaction() passes its own restorer to
 553     // rt_sigaction, so we need to do the same (we'll need to reimplement the
 554     // restorers; for x86_64 the restorer address can be obtained from
 555     // oldact->sa_restorer upon a call to sigaction(xxx, NULL, oldact).
 556     k_act.sa_restorer = u_act->sa_restorer;
 557   }
 558
 559   uptr result = internal_syscall(SYSCALL(rt_sigaction), (uptr)signum,
 560       (uptr)(u_act ? &k_act : NULL),
 561       (uptr)(u_oldact ? &k_oldact : NULL),
 562       (uptr)sizeof(__sanitizer_kernel_sigset_t));
 563
 564   if ((result == 0) && u_oldact) {
 565     u_oldact->handler = k_oldact.handler;
 566     u_oldact->sigaction = k_oldact.sigaction;
 567     internal_memcpy(&u_oldact->sa_mask, &k_oldact.sa_mask,
 568                     sizeof(__sanitizer_kernel_sigset_t));
 569     u_oldact->sa_flags = k_oldact.sa_flags;
 570     u_oldact->sa_restorer = k_oldact.sa_restorer;
 571   }
 572   return result;
 573 }
 574 #endif  // SANITIZER_LINUX
 575
 576 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
 577     __sanitizer_sigset_t *oldset) {
 578 #if SANITIZER_FREEBSD
 579   return internal_syscall(SYSCALL(sigprocmask), how, set, oldset);
 580 #else
 581   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
 582   __sanitizer_kernel_sigset_t *k_oldset = (__sanitizer_kernel_sigset_t *)oldset;
 583   return internal_syscall(SYSCALL(rt_sigprocmask), (uptr)how,
 584                           (uptr)&k_set->sig[0], (uptr)&k_oldset->sig[0],
 585                           sizeof(__sanitizer_kernel_sigset_t));
 586 #endif
 587 }
 588
 589 void internal_sigfillset(__sanitizer_sigset_t *set) {
 590   internal_memset(set, 0xff, sizeof(*set));
 591 }
 592
 593 #if SANITIZER_LINUX
 594 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
 595   signum -= 1;
 596   CHECK_GE(signum, 0);
 597   CHECK_LT(signum, sizeof(*set) * 8);
 598   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
 599   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
 600   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
 601   k_set->sig[idx] &= ~(1 << bit);
 602 }
 603 #endif  // SANITIZER_LINUX
 604
 605 // ThreadLister implementation.
 606 ThreadLister::ThreadLister(int pid)
 607   : pid_(pid),
 608     descriptor_(-1),
 609     buffer_(4096),
 610     error_(true),
 611     entry_((struct linux_dirent *)buffer_.data()),
 612     bytes_read_(0) {
 613   char task_directory_path[80];
 614   internal_snprintf(task_directory_path, sizeof(task_directory_path),
 615                     "/proc/%d/task/", pid);
 616   uptr openrv = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY);
 617   if (internal_iserror(openrv)) {
 618     error_ = true;
 619     Report("Can't open /proc/%d/task for reading.\n", pid);
 620   } else {
 621     error_ = false;
 622     descriptor_ = openrv;
 623   }
 624 }
 625
 626 int ThreadLister::GetNextTID() {
 627   int tid = -1;
 628   do {
 629     if (error_)
 630       return -1;
 631     if ((char *)entry_ >= &buffer_[bytes_read_] && !GetDirectoryEntries())
 632       return -1;
 633     if (entry_->d_ino != 0 && entry_->d_name[0] >= '0' &&
 634         entry_->d_name[0] <= '9') {
 635       // Found a valid tid.
 636       tid = (int)internal_atoll(entry_->d_name);
 637     }
 638     entry_ = (struct linux_dirent *)(((char *)entry_) + entry_->d_reclen);
 639   } while (tid < 0);
 640   return tid;
 641 }
 642
 643 void ThreadLister::Reset() {
 644   if (error_ || descriptor_ < 0)
 645     return;
 646   internal_lseek(descriptor_, 0, SEEK_SET);
 647 }
 648
 649 ThreadLister::~ThreadLister() {
 650   if (descriptor_ >= 0)
 651     internal_close(descriptor_);
 652 }
 653
 654 bool ThreadLister::error() { return error_; }
 655
 656 bool ThreadLister::GetDirectoryEntries() {
 657   CHECK_GE(descriptor_, 0);
 658   CHECK_NE(error_, true);
 659   bytes_read_ = internal_getdents(descriptor_,
 660                                   (struct linux_dirent *)buffer_.data(),
 661                                   buffer_.size());
 662   if (internal_iserror(bytes_read_)) {
 663     Report("Can't read directory entries from /proc/%d/task.\n", pid_);
 664     error_ = true;
 665     return false;
 666   } else if (bytes_read_ == 0) {
 667     return false;
 668   }
 669   entry_ = (struct linux_dirent *)buffer_.data();
 670   return true;
 671 }
 672
 673 uptr GetPageSize() {
 674 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__))
 675   return EXEC_PAGESIZE;
 676 #else
 677   return sysconf(_SC_PAGESIZE);  // EXEC_PAGESIZE may not be trustworthy.
 678 #endif
 679 }
 680
 681 static char proc_self_exe_cache_str[kMaxPathLength];
 682 static uptr proc_self_exe_cache_len = 0;
 683
 684 uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
 685   if (proc_self_exe_cache_len > 0) {
 686     // If available, use the cached module name.
 687     uptr module_name_len =
 688         internal_snprintf(buf, buf_len, "%s", proc_self_exe_cache_str);
 689     CHECK_LT(module_name_len, buf_len);
 690     return module_name_len;
 691   }
 692 #if SANITIZER_FREEBSD
 693   const int Mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1 };
 694   size_t Size = buf_len;
 695   bool IsErr = (sysctl(Mib, 4, buf, &Size, NULL, 0) != 0);
 696   int readlink_error = IsErr ? errno : 0;
 697   uptr module_name_len = Size;
 698 #else
 699   uptr module_name_len = internal_readlink(
 700       "/proc/self/exe", buf, buf_len);
 701   int readlink_error;
 702   bool IsErr = internal_iserror(module_name_len, &readlink_error);
 703 #endif
 704   if (IsErr) {
 705     // We can't read /proc/self/exe for some reason, assume the name of the
 706     // binary is unknown.
 707     Report("WARNING: readlink(\"/proc/self/exe\") failed with errno %d, "
 708            "some stack frames may not be symbolized\n", readlink_error);
 709     module_name_len = internal_snprintf(buf, buf_len, "/proc/self/exe");
 710     CHECK_LT(module_name_len, buf_len);
 711   }
 712   return module_name_len;
 713 }
 714
 715 void CacheBinaryName() {
 716   if (!proc_self_exe_cache_len) {
 717     proc_self_exe_cache_len =
 718         ReadBinaryName(proc_self_exe_cache_str, kMaxPathLength);
 719   }
 720 }
 721
 722 // Match full names of the form /path/to/base_name{-,.}*
 723 bool LibraryNameIs(const char *full_name, const char *base_name) {
 724   const char *name = full_name;
 725   // Strip path.
 726   while (*name != '\0') name++;
 727   while (name > full_name && *name != '/') name--;
 728   if (*name == '/') name++;
 729   uptr base_name_length = internal_strlen(base_name);
 730   if (internal_strncmp(name, base_name, base_name_length)) return false;
 731   return (name[base_name_length] == '-' || name[base_name_length] == '.');
 732 }
 733
 734 #if !SANITIZER_ANDROID
 735 // Call cb for each region mapped by map.
 736 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) {
 737 #if !SANITIZER_FREEBSD
 738   typedef ElfW(Phdr) Elf_Phdr;
 739   typedef ElfW(Ehdr) Elf_Ehdr;
 740 #endif  // !SANITIZER_FREEBSD
 741   char *base = (char *)map->l_addr;
 742   Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
 743   char *phdrs = base + ehdr->e_phoff;
 744   char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize;
 745
 746   // Find the segment with the minimum base so we can "relocate" the p_vaddr
 747   // fields.  Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC
 748   // objects have a non-zero base.
 749   uptr preferred_base = (uptr)-1;
 750   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
 751     Elf_Phdr *phdr = (Elf_Phdr *)iter;
 752     if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr)
 753       preferred_base = (uptr)phdr->p_vaddr;
 754   }
 755
 756   // Compute the delta from the real base to get a relocation delta.
 757   sptr delta = (uptr)base - preferred_base;
 758   // Now we can figure out what the loader really mapped.
 759   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
 760     Elf_Phdr *phdr = (Elf_Phdr *)iter;
 761     if (phdr->p_type == PT_LOAD) {
 762       uptr seg_start = phdr->p_vaddr + delta;
 763       uptr seg_end = seg_start + phdr->p_memsz;
 764       // None of these values are aligned.  We consider the ragged edges of the
 765       // load command as defined, since they are mapped from the file.
 766       seg_start = RoundDownTo(seg_start, GetPageSizeCached());
 767       seg_end = RoundUpTo(seg_end, GetPageSizeCached());
 768       cb((void *)seg_start, seg_end - seg_start);
 769     }
 770   }
 771 }
 772 #endif
 773
 774 #if defined(__x86_64__) && SANITIZER_LINUX
 775 // We cannot use glibc's clone wrapper, because it messes with the child
 776 // task's TLS. It writes the PID and TID of the child task to its thread
 777 // descriptor, but in our case the child task shares the thread descriptor with
 778 // the parent (because we don't know how to allocate a new thread
 779 // descriptor to keep glibc happy). So the stock version of clone(), when
 780 // used with CLONE_VM, would end up corrupting the parent's thread descriptor.
 781 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
 782                     int *parent_tidptr, void *newtls, int *child_tidptr) {
 783   long long res;
 784   if (!fn || !child_stack)
 785     return -EINVAL;
 786   CHECK_EQ(0, (uptr)child_stack % 16);
 787   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
 788   ((unsigned long long *)child_stack)[0] = (uptr)fn;
 789   ((unsigned long long *)child_stack)[1] = (uptr)arg;
 790   register void *r8 __asm__("r8") = newtls;
 791   register int *r10 __asm__("r10") = child_tidptr;
 792   __asm__ __volatile__(
 793                        /* %rax = syscall(%rax = SYSCALL(clone),
 794                         *                %rdi = flags,
 795                         *                %rsi = child_stack,
 796                         *                %rdx = parent_tidptr,
 797                         *                %r8  = new_tls,
 798                         *                %r10 = child_tidptr)
 799                         */
 800                        "syscall\n"
 801
 802                        /* if (%rax != 0)
 803                         *   return;
 804                         */
 805                        "testq  %%rax,%%rax\n"
 806                        "jnz    1f\n"
 807
 808                        /* In the child. Terminate unwind chain. */
 809                        // XXX: We should also terminate the CFI unwind chain
 810                        // here. Unfortunately clang 3.2 doesn't support the
 811                        // necessary CFI directives, so we skip that part.
 812                        "xorq   %%rbp,%%rbp\n"
 813
 814                        /* Call "fn(arg)". */
 815                        "popq   %%rax\n"
 816                        "popq   %%rdi\n"
 817                        "call   *%%rax\n"
 818
 819                        /* Call _exit(%rax). */
 820                        "movq   %%rax,%%rdi\n"
 821                        "movq   %2,%%rax\n"
 822                        "syscall\n"
 823
 824                        /* Return to parent. */
 825                      "1:\n"
 826                        : "=a" (res)
 827                        : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
 828                          "S"(child_stack),
 829                          "D"(flags),
 830                          "d"(parent_tidptr),
 831                          "r"(r8),
 832                          "r"(r10)
 833                        : "rsp", "memory", "r11", "rcx");
 834   return res;
 835 }
 836 #endif  // defined(__x86_64__) && SANITIZER_LINUX
 837
 838 #if SANITIZER_ANDROID
 839 // This thing is not, strictly speaking, async signal safe, but it does not seem
 840 // to cause any issues. Alternative is writing to log devices directly, but
 841 // their location and message format might change in the future, so we'd really
 842 // like to avoid that.
 843 void AndroidLogWrite(const char *buffer) {
 844   char *copy = internal_strdup(buffer);
 845   char *p = copy;
 846   char *q;
 847   // __android_log_write has an implicit message length limit.
 848   // Print one line at a time.
 849   do {
 850     q = internal_strchr(p, '\n');
 851     if (q) *q = '\0';
 852     __android_log_write(ANDROID_LOG_INFO, NULL, p);
 853     if (q) p = q + 1;
 854   } while (q);
 855   InternalFree(copy);
 856 }
 857
 858 void GetExtraActivationFlags(char *buf, uptr size) {
 859   CHECK(size > PROP_VALUE_MAX);
 860   __system_property_get("asan.options", buf);
 861 }
 862 #endif
 863
 864 bool IsDeadlySignal(int signum) {
 865   return (signum == SIGSEGV) && common_flags()->handle_segv;
 866 }
 867
 868 }  // namespace __sanitizer
 869
 870 #endif  // SANITIZER_FREEBSD || SANITIZER_LINUX