libsanitizer/sanitizer_common/sanitizer_posix.cpp

   1 //===-- sanitizer_posix.cpp -----------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is shared between AddressSanitizer and ThreadSanitizer
  10 // run-time libraries and implements POSIX-specific functions from
  11 // sanitizer_posix.h.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "sanitizer_platform.h"
  15
  16 #if SANITIZER_POSIX
  17
  18 #include "sanitizer_common.h"
  19 #include "sanitizer_file.h"
  20 #include "sanitizer_flags.h"
  21 #include "sanitizer_libc.h"
  22 #include "sanitizer_posix.h"
  23 #include "sanitizer_procmaps.h"
  24
  25 #include <errno.h>
  26 #include <fcntl.h>
  27 #include <signal.h>
  28 #include <sys/mman.h>
  29
  30 #if SANITIZER_FREEBSD
  31 // The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
  32 // that, it was never implemented.  So just define it to zero.
  33 #undef  MAP_NORESERVE
  34 #define MAP_NORESERVE 0
  35 #endif
  36
  37 namespace __sanitizer {
  38
  39 // ------------- sanitizer_common.h
  40 uptr GetMmapGranularity() {
  41   return GetPageSize();
  42 }
  43
  44 bool ErrorIsOOM(error_t err) { return err == ENOMEM; }
  45
  46 void *MmapOrDie(uptr size, const char *mem_type, bool raw_report) {
  47   size = RoundUpTo(size, GetPageSizeCached());
  48   uptr res = MmapNamed(nullptr, size, PROT_READ | PROT_WRITE,
  49                        MAP_PRIVATE | MAP_ANON, mem_type);
  50   int reserrno;
  51   if (UNLIKELY(internal_iserror(res, &reserrno)))
  52     ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno, raw_report);
  53   IncreaseTotalMmap(size);
  54   return (void *)res;
  55 }
  56
  57 void UnmapOrDie(void *addr, uptr size) {
  58   if (!addr || !size) return;
  59   uptr res = internal_munmap(addr, size);
  60   if (UNLIKELY(internal_iserror(res))) {
  61     Report("ERROR: %s failed to deallocate 0x%zx (%zd) bytes at address %p\n",
  62            SanitizerToolName, size, size, addr);
  63     CHECK("unable to unmap" && 0);
  64   }
  65   DecreaseTotalMmap(size);
  66 }
  67
  68 void *MmapOrDieOnFatalError(uptr size, const char *mem_type) {
  69   size = RoundUpTo(size, GetPageSizeCached());
  70   uptr res = MmapNamed(nullptr, size, PROT_READ | PROT_WRITE,
  71                        MAP_PRIVATE | MAP_ANON, mem_type);
  72   int reserrno;
  73   if (UNLIKELY(internal_iserror(res, &reserrno))) {
  74     if (reserrno == ENOMEM)
  75       return nullptr;
  76     ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno);
  77   }
  78   IncreaseTotalMmap(size);
  79   return (void *)res;
  80 }
  81
  82 // We want to map a chunk of address space aligned to 'alignment'.
  83 // We do it by mapping a bit more and then unmapping redundant pieces.
  84 // We probably can do it with fewer syscalls in some OS-dependent way.
  85 void *MmapAlignedOrDieOnFatalError(uptr size, uptr alignment,
  86                                    const char *mem_type) {
  87   CHECK(IsPowerOfTwo(size));
  88   CHECK(IsPowerOfTwo(alignment));
  89   uptr map_size = size + alignment;
  90   uptr map_res = (uptr)MmapOrDieOnFatalError(map_size, mem_type);
  91   if (UNLIKELY(!map_res))
  92     return nullptr;
  93   uptr map_end = map_res + map_size;
  94   uptr res = map_res;
  95   if (!IsAligned(res, alignment)) {
  96     res = (map_res + alignment - 1) & ~(alignment - 1);
  97     UnmapOrDie((void*)map_res, res - map_res);
  98   }
  99   uptr end = res + size;
 100   end = RoundUpTo(end, GetPageSizeCached());
 101   if (end != map_end)
 102     UnmapOrDie((void*)end, map_end - end);
 103   return (void*)res;
 104 }
 105
 106 void *MmapNoReserveOrDie(uptr size, const char *mem_type) {
 107   size = RoundUpTo(size, GetPageSizeCached());
 108   uptr p = MmapNamed(nullptr, size, PROT_READ | PROT_WRITE,
 109                      MAP_PRIVATE | MAP_ANON | MAP_NORESERVE, mem_type);
 110   int reserrno;
 111   if (UNLIKELY(internal_iserror(p, &reserrno)))
 112     ReportMmapFailureAndDie(size, mem_type, "allocate noreserve", reserrno);
 113   IncreaseTotalMmap(size);
 114   return (void *)p;
 115 }
 116
 117 static void *MmapFixedImpl(uptr fixed_addr, uptr size, bool tolerate_enomem,
 118                            const char *name) {
 119   size = RoundUpTo(size, GetPageSizeCached());
 120   fixed_addr = RoundDownTo(fixed_addr, GetPageSizeCached());
 121   uptr p = MmapNamed((void *)fixed_addr, size, PROT_READ | PROT_WRITE,
 122                      MAP_PRIVATE | MAP_ANON | MAP_FIXED, name);
 123   int reserrno;
 124   if (UNLIKELY(internal_iserror(p, &reserrno))) {
 125     if (tolerate_enomem && reserrno == ENOMEM)
 126       return nullptr;
 127     char mem_type[40];
 128     internal_snprintf(mem_type, sizeof(mem_type), "memory at address 0x%zx",
 129                       fixed_addr);
 130     ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno);
 131   }
 132   IncreaseTotalMmap(size);
 133   return (void *)p;
 134 }
 135
 136 void *MmapFixedOrDie(uptr fixed_addr, uptr size, const char *name) {
 137   return MmapFixedImpl(fixed_addr, size, false /*tolerate_enomem*/, name);
 138 }
 139
 140 void *MmapFixedOrDieOnFatalError(uptr fixed_addr, uptr size, const char *name) {
 141   return MmapFixedImpl(fixed_addr, size, true /*tolerate_enomem*/, name);
 142 }
 143
 144 bool MprotectNoAccess(uptr addr, uptr size) {
 145   return 0 == internal_mprotect((void*)addr, size, PROT_NONE);
 146 }
 147
 148 bool MprotectReadOnly(uptr addr, uptr size) {
 149   return 0 == internal_mprotect((void *)addr, size, PROT_READ);
 150 }
 151
 152 #if !SANITIZER_APPLE
 153 void MprotectMallocZones(void *addr, int prot) {}
 154 #endif
 155
 156 fd_t OpenFile(const char *filename, FileAccessMode mode, error_t *errno_p) {
 157   if (ShouldMockFailureToOpen(filename))
 158     return kInvalidFd;
 159   int flags;
 160   switch (mode) {
 161     case RdOnly: flags = O_RDONLY; break;
 162     case WrOnly: flags = O_WRONLY | O_CREAT | O_TRUNC; break;
 163     case RdWr: flags = O_RDWR | O_CREAT; break;
 164   }
 165   fd_t res = internal_open(filename, flags, 0660);
 166   if (internal_iserror(res, errno_p))
 167     return kInvalidFd;
 168   return ReserveStandardFds(res);
 169 }
 170
 171 void CloseFile(fd_t fd) {
 172   internal_close(fd);
 173 }
 174
 175 bool ReadFromFile(fd_t fd, void *buff, uptr buff_size, uptr *bytes_read,
 176                   error_t *error_p) {
 177   uptr res = internal_read(fd, buff, buff_size);
 178   if (internal_iserror(res, error_p))
 179     return false;
 180   if (bytes_read)
 181     *bytes_read = res;
 182   return true;
 183 }
 184
 185 bool WriteToFile(fd_t fd, const void *buff, uptr buff_size, uptr *bytes_written,
 186                  error_t *error_p) {
 187   uptr res = internal_write(fd, buff, buff_size);
 188   if (internal_iserror(res, error_p))
 189     return false;
 190   if (bytes_written)
 191     *bytes_written = res;
 192   return true;
 193 }
 194
 195 void *MapFileToMemory(const char *file_name, uptr *buff_size) {
 196   fd_t fd = OpenFile(file_name, RdOnly);
 197   CHECK(fd != kInvalidFd);
 198   uptr fsize = internal_filesize(fd);
 199   CHECK_NE(fsize, (uptr)-1);
 200   CHECK_GT(fsize, 0);
 201   *buff_size = RoundUpTo(fsize, GetPageSizeCached());
 202   uptr map = internal_mmap(nullptr, *buff_size, PROT_READ, MAP_PRIVATE, fd, 0);
 203   return internal_iserror(map) ? nullptr : (void *)map;
 204 }
 205
 206 void *MapWritableFileToMemory(void *addr, uptr size, fd_t fd, OFF_T offset) {
 207   uptr flags = MAP_SHARED;
 208   if (addr) flags |= MAP_FIXED;
 209   uptr p = internal_mmap(addr, size, PROT_READ | PROT_WRITE, flags, fd, offset);
 210   int mmap_errno = 0;
 211   if (internal_iserror(p, &mmap_errno)) {
 212     Printf("could not map writable file (%d, %lld, %zu): %zd, errno: %d\n",
 213            fd, (long long)offset, size, p, mmap_errno);
 214     return nullptr;
 215   }
 216   return (void *)p;
 217 }
 218
 219 static inline bool IntervalsAreSeparate(uptr start1, uptr end1,
 220                                         uptr start2, uptr end2) {
 221   CHECK(start1 <= end1);
 222   CHECK(start2 <= end2);
 223   return (end1 < start2) || (end2 < start1);
 224 }
 225
 226 // FIXME: this is thread-unsafe, but should not cause problems most of the time.
 227 // When the shadow is mapped only a single thread usually exists (plus maybe
 228 // several worker threads on Mac, which aren't expected to map big chunks of
 229 // memory).
 230 bool MemoryRangeIsAvailable(uptr range_start, uptr range_end) {
 231   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 232   if (proc_maps.Error())
 233     return true; // and hope for the best
 234   MemoryMappedSegment segment;
 235   while (proc_maps.Next(&segment)) {
 236     if (segment.start == segment.end) continue;  // Empty range.
 237     CHECK_NE(0, segment.end);
 238     if (!IntervalsAreSeparate(segment.start, segment.end - 1, range_start,
 239                               range_end))
 240       return false;
 241   }
 242   return true;
 243 }
 244
 245 #if !SANITIZER_APPLE
 246 void DumpProcessMap() {
 247   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 248   const sptr kBufSize = 4095;
 249   char *filename = (char*)MmapOrDie(kBufSize, __func__);
 250   MemoryMappedSegment segment(filename, kBufSize);
 251   Report("Process memory map follows:\n");
 252   while (proc_maps.Next(&segment)) {
 253     Printf("\t%p-%p\t%s\n", (void *)segment.start, (void *)segment.end,
 254            segment.filename);
 255   }
 256   Report("End of process memory map.\n");
 257   UnmapOrDie(filename, kBufSize);
 258 }
 259 #endif
 260
 261 const char *GetPwd() {
 262   return GetEnv("PWD");
 263 }
 264
 265 bool IsPathSeparator(const char c) {
 266   return c == '/';
 267 }
 268
 269 bool IsAbsolutePath(const char *path) {
 270   return path != nullptr && IsPathSeparator(path[0]);
 271 }
 272
 273 void ReportFile::Write(const char *buffer, uptr length) {
 274   SpinMutexLock l(mu);
 275   ReopenIfNecessary();
 276   internal_write(fd, buffer, length);
 277 }
 278
 279 bool GetCodeRangeForFile(const char *module, uptr *start, uptr *end) {
 280   MemoryMappingLayout proc_maps(/*cache_enabled*/false);
 281   InternalMmapVector<char> buff(kMaxPathLength);
 282   MemoryMappedSegment segment(buff.data(), buff.size());
 283   while (proc_maps.Next(&segment)) {
 284     if (segment.IsExecutable() &&
 285         internal_strcmp(module, segment.filename) == 0) {
 286       *start = segment.start;
 287       *end = segment.end;
 288       return true;
 289     }
 290   }
 291   return false;
 292 }
 293
 294 uptr SignalContext::GetAddress() const {
 295   auto si = static_cast<const siginfo_t *>(siginfo);
 296   return (uptr)si->si_addr;
 297 }
 298
 299 bool SignalContext::IsMemoryAccess() const {
 300   auto si = static_cast<const siginfo_t *>(siginfo);
 301   return si->si_signo == SIGSEGV || si->si_signo == SIGBUS;
 302 }
 303
 304 int SignalContext::GetType() const {
 305   return static_cast<const siginfo_t *>(siginfo)->si_signo;
 306 }
 307
 308 const char *SignalContext::Describe() const {
 309   switch (GetType()) {
 310     case SIGFPE:
 311       return "FPE";
 312     case SIGILL:
 313       return "ILL";
 314     case SIGABRT:
 315       return "ABRT";
 316     case SIGSEGV:
 317       return "SEGV";
 318     case SIGBUS:
 319       return "BUS";
 320     case SIGTRAP:
 321       return "TRAP";
 322   }
 323   return "UNKNOWN SIGNAL";
 324 }
 325
 326 fd_t ReserveStandardFds(fd_t fd) {
 327   CHECK_GE(fd, 0);
 328   if (fd > 2)
 329     return fd;
 330   bool used[3];
 331   internal_memset(used, 0, sizeof(used));
 332   while (fd <= 2) {
 333     used[fd] = true;
 334     fd = internal_dup(fd);
 335   }
 336   for (int i = 0; i <= 2; ++i)
 337     if (used[i])
 338       internal_close(i);
 339   return fd;
 340 }
 341
 342 bool ShouldMockFailureToOpen(const char *path) {
 343   return common_flags()->test_only_emulate_no_memorymap &&
 344          internal_strncmp(path, "/proc/", 6) == 0;
 345 }
 346
 347 #if SANITIZER_LINUX && !SANITIZER_ANDROID && !SANITIZER_GO
 348 int GetNamedMappingFd(const char *name, uptr size, int *flags) {
 349   if (!common_flags()->decorate_proc_maps || !name)
 350     return -1;
 351   char shmname[200];
 352   CHECK(internal_strlen(name) < sizeof(shmname) - 10);
 353   internal_snprintf(shmname, sizeof(shmname), "/dev/shm/%zu [%s]",
 354                     internal_getpid(), name);
 355   int o_cloexec = 0;
 356 #if defined(O_CLOEXEC)
 357   o_cloexec = O_CLOEXEC;
 358 #endif
 359   int fd = ReserveStandardFds(
 360       internal_open(shmname, O_RDWR | O_CREAT | O_TRUNC | o_cloexec, S_IRWXU));
 361   CHECK_GE(fd, 0);
 362   int res = internal_ftruncate(fd, size);
 363 #if !defined(O_CLOEXEC)
 364   res = fcntl(fd, F_SETFD, FD_CLOEXEC);
 365   CHECK_EQ(0, res);
 366 #endif
 367   CHECK_EQ(0, res);
 368   res = internal_unlink(shmname);
 369   CHECK_EQ(0, res);
 370   *flags &= ~(MAP_ANON | MAP_ANONYMOUS);
 371   return fd;
 372 }
 373 #else
 374 int GetNamedMappingFd(const char *name, uptr size, int *flags) {
 375   return -1;
 376 }
 377 #endif
 378
 379 #if SANITIZER_ANDROID
 380 #define PR_SET_VMA 0x53564d41
 381 #define PR_SET_VMA_ANON_NAME 0
 382 void DecorateMapping(uptr addr, uptr size, const char *name) {
 383   if (!common_flags()->decorate_proc_maps || !name)
 384     return;
 385   internal_prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, addr, size, (uptr)name);
 386 }
 387 #else
 388 void DecorateMapping(uptr addr, uptr size, const char *name) {
 389 }
 390 #endif
 391
 392 uptr MmapNamed(void *addr, uptr length, int prot, int flags, const char *name) {
 393   int fd = GetNamedMappingFd(name, length, &flags);
 394   uptr res = internal_mmap(addr, length, prot, flags, fd, 0);
 395   if (!internal_iserror(res))
 396     DecorateMapping(res, length, name);
 397   return res;
 398 }
 399
 400
 401 } // namespace __sanitizer
 402
 403 #endif // SANITIZER_POSIX