sanitizer_linux.cc revision 5d71de26cedae3dafc17449fe0182045c0bd20e8
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> 53extern "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} 58extern 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> 72struct kernel_timeval { 73 long tv_sec; 74 long tv_usec; 75}; 76 77// <linux/futex.h> is broken on some linux distributions. 78const int FUTEX_WAIT = 0; 79const 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 91namespace __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 100uptr 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 111uptr internal_munmap(void *addr, uptr length) { 112 return internal_syscall(SYSCALL(munmap), (uptr)addr, length); 113} 114 115uptr internal_close(fd_t fd) { 116 return internal_syscall(SYSCALL(close), fd); 117} 118 119uptr 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 127uptr 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 136uptr OpenFile(const char *filename, bool write) { 137 return internal_open(filename, 138 write ? O_RDWR | O_CREAT /*| O_CLOEXEC*/ : O_RDONLY, 0660); 139} 140 141uptr 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 148uptr 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 155uptr 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 162static 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 181uptr 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 197uptr 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 213uptr 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 224uptr 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 231uptr 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 239uptr 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 248uptr 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 256uptr 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 265uptr internal_sched_yield() { 266 return internal_syscall(SYSCALL(sched_yield)); 267} 268 269void 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 278uptr 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 285bool 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 299uptr GetTid() { 300#if SANITIZER_FREEBSD 301 return (uptr)pthread_self(); 302#else 303 return internal_syscall(SYSCALL(gettid)); 304#endif 305} 306 307u64 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. 321const 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 360extern "C" { 361 SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end; 362} 363 364#if !SANITIZER_GO 365static 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 385static 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 402void 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 414void 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 423enum MutexState { 424 MtxUnlocked = 0, 425 MtxLocked = 1, 426 MtxSleeping = 2 427}; 428 429BlockingMutex::BlockingMutex(LinkerInitialized) { 430 CHECK_EQ(owner_, 0); 431} 432 433BlockingMutex::BlockingMutex() { 434 internal_memset(this, 0, sizeof(*this)); 435} 436 437void 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 450void 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 463void 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. 472struct 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. 485uptr 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 490uptr internal_waitpid(int pid, int *status, int options) { 491 return internal_syscall(SYSCALL(wait4), pid, (uptr)status, options, 492 0 /* rusage */); 493} 494 495uptr internal_getpid() { 496 return internal_syscall(SYSCALL(getpid)); 497} 498 499uptr internal_getppid() { 500 return internal_syscall(SYSCALL(getppid)); 501} 502 503uptr 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 511uptr 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 516uptr 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 521uptr internal_sigaltstack(const struct sigaltstack *ss, 522 struct sigaltstack *oss) { 523 return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss); 524} 525 526int 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). 536int 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 576uptr 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 589void internal_sigfillset(__sanitizer_sigset_t *set) { 590 internal_memset(set, 0xff, sizeof(*set)); 591} 592 593#if SANITIZER_LINUX 594void 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. 606ThreadLister::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 626int 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 643void ThreadLister::Reset() { 644 if (error_ || descriptor_ < 0) 645 return; 646 internal_lseek(descriptor_, 0, SEEK_SET); 647} 648 649ThreadLister::~ThreadLister() { 650 if (descriptor_ >= 0) 651 internal_close(descriptor_); 652} 653 654bool ThreadLister::error() { return error_; } 655 656bool 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 673uptr 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 681static char proc_self_exe_cache_str[kMaxPathLength]; 682static uptr proc_self_exe_cache_len = 0; 683 684uptr 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 715void 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{-,.}* 723bool 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. 736void 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. 781uptr 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. 843void 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 858void GetExtraActivationFlags(char *buf, uptr size) { 859 CHECK(size > PROP_VALUE_MAX); 860 __system_property_get("asan.options", buf); 861} 862#endif 863 864bool IsDeadlySignal(int signum) { 865 return (signum == SIGSEGV) && common_flags()->handle_segv; 866} 867 868} // namespace __sanitizer 869 870#endif // SANITIZER_FREEBSD || SANITIZER_LINUX 871