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   int reserrno;
  61   if (UNLIKELY(internal_iserror(res, &reserrno)))
  62     ReportMunmapFailureAndDie(addr, size, reserrno);
  63   DecreaseTotalMmap(size);
  64 }
  65
  66 void *MmapOrDieOnFatalError(uptr size, const char *mem_type) {
  67   size = RoundUpTo(size, GetPageSizeCached());
  68   uptr res = MmapNamed(nullptr, size, PROT_READ | PROT_WRITE,
  69                        MAP_PRIVATE | MAP_ANON, mem_type);
  70   int reserrno;
  71   if (UNLIKELY(internal_iserror(res, &reserrno))) {
  72     if (reserrno == ENOMEM)
  73       return nullptr;
  74     ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno);
  75   }
  76   IncreaseTotalMmap(size);
  77   return (void *)res;
  78 }
  79
  80 // We want to map a chunk of address space aligned to 'alignment'.
  81 // We do it by mapping a bit more and then unmapping redundant pieces.
  82 // We probably can do it with fewer syscalls in some OS-dependent way.
  83 void *MmapAlignedOrDieOnFatalError(uptr size, uptr alignment,
  84                                    const char *mem_type) {
  85   CHECK(IsPowerOfTwo(size));
  86   CHECK(IsPowerOfTwo(alignment));
  87   uptr map_size = size + alignment;
  88   // mmap maps entire pages and rounds up map_size needs to be a an integral
  89   // number of pages.
  90   // We need to be aware of this size for calculating end and for unmapping
  91   // fragments before and after the alignment region.
  92   map_size = RoundUpTo(map_size, GetPageSizeCached());
  93   uptr map_res = (uptr)MmapOrDieOnFatalError(map_size, mem_type);
  94   if (UNLIKELY(!map_res))
  95     return nullptr;
  96   uptr res = map_res;
  97   if (!IsAligned(res, alignment)) {
  98     res = (map_res + alignment - 1) & ~(alignment - 1);
  99     UnmapOrDie((void*)map_res, res - map_res);
 100   }
 101   uptr map_end = map_res + map_size;
 102   uptr end = res + size;
 103   end = RoundUpTo(end, GetPageSizeCached());
 104   if (end != map_end) {
 105     CHECK_LT(end, map_end);
 106     UnmapOrDie((void*)end, map_end - end);
 107   }
 108   return (void*)res;
 109 }
 110
 111 void *MmapNoReserveOrDie(uptr size, const char *mem_type) {
 112   size = RoundUpTo(size, GetPageSizeCached());
 113   uptr p = MmapNamed(nullptr, size, PROT_READ | PROT_WRITE,
 114                      MAP_PRIVATE | MAP_ANON | MAP_NORESERVE, mem_type);
 115   int reserrno;
 116   if (UNLIKELY(internal_iserror(p, &reserrno)))
 117     ReportMmapFailureAndDie(size, mem_type, "allocate noreserve", reserrno);
 118   IncreaseTotalMmap(size);
 119   return (void *)p;
 120 }
 121
 122 static void *MmapFixedImpl(uptr fixed_addr, uptr size, bool tolerate_enomem,
 123                            const char *name) {
 124   size = RoundUpTo(size, GetPageSizeCached());
 125   fixed_addr = RoundDownTo(fixed_addr, GetPageSizeCached());
 126   uptr p = MmapNamed((void *)fixed_addr, size, PROT_READ | PROT_WRITE,
 127                      MAP_PRIVATE | MAP_ANON | MAP_FIXED, name);
 128   int reserrno;
 129   if (UNLIKELY(internal_iserror(p, &reserrno))) {
 130     if (tolerate_enomem && reserrno == ENOMEM)
 131       return nullptr;
 132     char mem_type[40];
 133     internal_snprintf(mem_type, sizeof(mem_type), "memory at address 0x%zx",
 134                       fixed_addr);
 135     ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno);
 136   }
 137   IncreaseTotalMmap(size);
 138   return (void *)p;
 139 }
 140
 141 void *MmapFixedOrDie(uptr fixed_addr, uptr size, const char *name) {
 142   return MmapFixedImpl(fixed_addr, size, false /*tolerate_enomem*/, name);
 143 }
 144
 145 void *MmapFixedOrDieOnFatalError(uptr fixed_addr, uptr size, const char *name) {
 146   return MmapFixedImpl(fixed_addr, size, true /*tolerate_enomem*/, name);
 147 }
 148
 149 bool MprotectNoAccess(uptr addr, uptr size) {
 150   return 0 == internal_mprotect((void*)addr, size, PROT_NONE);
 151 }
 152
 153 bool MprotectReadOnly(uptr addr, uptr size) {
 154   return 0 == internal_mprotect((void *)addr, size, PROT_READ);
 155 }
 156
 157 #if !SANITIZER_APPLE
 158 void MprotectMallocZones(void *addr, int prot) {}
 159 #endif
 160
 161 fd_t OpenFile(const char *filename, FileAccessMode mode, error_t *errno_p) {
 162   if (ShouldMockFailureToOpen(filename))
 163     return kInvalidFd;
 164   int flags;
 165   switch (mode) {
 166     case RdOnly: flags = O_RDONLY; break;
 167     case WrOnly: flags = O_WRONLY | O_CREAT | O_TRUNC; break;
 168     case RdWr: flags = O_RDWR | O_CREAT; break;
 169   }
 170   fd_t res = internal_open(filename, flags, 0660);
 171   if (internal_iserror(res, errno_p))
 172     return kInvalidFd;
 173   return ReserveStandardFds(res);
 174 }
 175
 176 void CloseFile(fd_t fd) {
 177   internal_close(fd);
 178 }
 179
 180 bool ReadFromFile(fd_t fd, void *buff, uptr buff_size, uptr *bytes_read,
 181                   error_t *error_p) {
 182   uptr res = internal_read(fd, buff, buff_size);
 183   if (internal_iserror(res, error_p))
 184     return false;
 185   if (bytes_read)
 186     *bytes_read = res;
 187   return true;
 188 }
 189
 190 bool WriteToFile(fd_t fd, const void *buff, uptr buff_size, uptr *bytes_written,
 191                  error_t *error_p) {
 192   uptr res = internal_write(fd, buff, buff_size);
 193   if (internal_iserror(res, error_p))
 194     return false;
 195   if (bytes_written)
 196     *bytes_written = res;
 197   return true;
 198 }
 199
 200 void *MapFileToMemory(const char *file_name, uptr *buff_size) {
 201   fd_t fd = OpenFile(file_name, RdOnly);
 202   CHECK(fd != kInvalidFd);
 203   uptr fsize = internal_filesize(fd);
 204   CHECK_NE(fsize, (uptr)-1);
 205   CHECK_GT(fsize, 0);
 206   *buff_size = RoundUpTo(fsize, GetPageSizeCached());
 207   uptr map = internal_mmap(nullptr, *buff_size, PROT_READ, MAP_PRIVATE, fd, 0);
 208   return internal_iserror(map) ? nullptr : (void *)map;
 209 }
 210
 211 void *MapWritableFileToMemory(void *addr, uptr size, fd_t fd, OFF_T offset) {
 212   uptr flags = MAP_SHARED;
 213   if (addr) flags |= MAP_FIXED;
 214   uptr p = internal_mmap(addr, size, PROT_READ | PROT_WRITE, flags, fd, offset);
 215   int mmap_errno = 0;
 216   if (internal_iserror(p, &mmap_errno)) {
 217     Printf("could not map writable file (%d, %lld, %zu): %zd, errno: %d\n",
 218            fd, (long long)offset, size, p, mmap_errno);
 219     return nullptr;
 220   }
 221   return (void *)p;
 222 }
 223
 224 static inline bool IntervalsAreSeparate(uptr start1, uptr end1,
 225                                         uptr start2, uptr end2) {
 226   CHECK(start1 <= end1);
 227   CHECK(start2 <= end2);
 228   return (end1 < start2) || (end2 < start1);
 229 }
 230
 231 // FIXME: this is thread-unsafe, but should not cause problems most of the time.
 232 // When the shadow is mapped only a single thread usually exists (plus maybe
 233 // several worker threads on Mac, which aren't expected to map big chunks of
 234 // memory).
 235 bool MemoryRangeIsAvailable(uptr range_start, uptr range_end) {
 236   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 237   if (proc_maps.Error())
 238     return true; // and hope for the best
 239   MemoryMappedSegment segment;
 240   while (proc_maps.Next(&segment)) {
 241     if (segment.start == segment.end) continue;  // Empty range.
 242     CHECK_NE(0, segment.end);
 243     if (!IntervalsAreSeparate(segment.start, segment.end - 1, range_start,
 244                               range_end))
 245       return false;
 246   }
 247   return true;
 248 }
 249
 250 #if !SANITIZER_APPLE
 251 void DumpProcessMap() {
 252   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 253   const sptr kBufSize = 4095;
 254   char *filename = (char*)MmapOrDie(kBufSize, __func__);
 255   MemoryMappedSegment segment(filename, kBufSize);
 256   Report("Process memory map follows:\n");
 257   while (proc_maps.Next(&segment)) {
 258     Printf("\t%p-%p\t%s\n", (void *)segment.start, (void *)segment.end,
 259            segment.filename);
 260   }
 261   Report("End of process memory map.\n");
 262   UnmapOrDie(filename, kBufSize);
 263 }
 264 #endif
 265
 266 const char *GetPwd() {
 267   return GetEnv("PWD");
 268 }
 269
 270 bool IsPathSeparator(const char c) {
 271   return c == '/';
 272 }
 273
 274 bool IsAbsolutePath(const char *path) {
 275   return path != nullptr && IsPathSeparator(path[0]);
 276 }
 277
 278 void ReportFile::Write(const char *buffer, uptr length) {
 279   SpinMutexLock l(mu);
 280   ReopenIfNecessary();
 281   internal_write(fd, buffer, length);
 282 }
 283
 284 bool GetCodeRangeForFile(const char *module, uptr *start, uptr *end) {
 285   MemoryMappingLayout proc_maps(/*cache_enabled*/false);
 286   InternalMmapVector<char> buff(kMaxPathLength);
 287   MemoryMappedSegment segment(buff.data(), buff.size());
 288   while (proc_maps.Next(&segment)) {
 289     if (segment.IsExecutable() &&
 290         internal_strcmp(module, segment.filename) == 0) {
 291       *start = segment.start;
 292       *end = segment.end;
 293       return true;
 294     }
 295   }
 296   return false;
 297 }
 298
 299 uptr SignalContext::GetAddress() const {
 300   auto si = static_cast<const siginfo_t *>(siginfo);
 301   return (uptr)si->si_addr;
 302 }
 303
 304 bool SignalContext::IsMemoryAccess() const {
 305   auto si = static_cast<const siginfo_t *>(siginfo);
 306   return si->si_signo == SIGSEGV || si->si_signo == SIGBUS;
 307 }
 308
 309 int SignalContext::GetType() const {
 310   return static_cast<const siginfo_t *>(siginfo)->si_signo;
 311 }
 312
 313 const char *SignalContext::Describe() const {
 314   switch (GetType()) {
 315     case SIGFPE:
 316       return "FPE";
 317     case SIGILL:
 318       return "ILL";
 319     case SIGABRT:
 320       return "ABRT";
 321     case SIGSEGV:
 322       return "SEGV";
 323     case SIGBUS:
 324       return "BUS";
 325     case SIGTRAP:
 326       return "TRAP";
 327   }
 328   return "UNKNOWN SIGNAL";
 329 }
 330
 331 fd_t ReserveStandardFds(fd_t fd) {
 332   CHECK_GE(fd, 0);
 333   if (fd > 2)
 334     return fd;
 335   bool used[3];
 336   internal_memset(used, 0, sizeof(used));
 337   while (fd <= 2) {
 338     used[fd] = true;
 339     fd = internal_dup(fd);
 340   }
 341   for (int i = 0; i <= 2; ++i)
 342     if (used[i])
 343       internal_close(i);
 344   return fd;
 345 }
 346
 347 bool ShouldMockFailureToOpen(const char *path) {
 348   return common_flags()->test_only_emulate_no_memorymap &&
 349          internal_strncmp(path, "/proc/", 6) == 0;
 350 }
 351
 352 #if SANITIZER_LINUX && !SANITIZER_ANDROID && !SANITIZER_GO
 353 int GetNamedMappingFd(const char *name, uptr size, int *flags) {
 354   if (!common_flags()->decorate_proc_maps || !name)
 355     return -1;
 356   char shmname[200];
 357   CHECK(internal_strlen(name) < sizeof(shmname) - 10);
 358   internal_snprintf(shmname, sizeof(shmname), "/dev/shm/%zu [%s]",
 359                     internal_getpid(), name);
 360   int o_cloexec = 0;
 361 #if defined(O_CLOEXEC)
 362   o_cloexec = O_CLOEXEC;
 363 #endif
 364   int fd = ReserveStandardFds(
 365       internal_open(shmname, O_RDWR | O_CREAT | O_TRUNC | o_cloexec, S_IRWXU));
 366   CHECK_GE(fd, 0);
 367   int res = internal_ftruncate(fd, size);
 368 #if !defined(O_CLOEXEC)
 369   res = fcntl(fd, F_SETFD, FD_CLOEXEC);
 370   CHECK_EQ(0, res);
 371 #endif
 372   CHECK_EQ(0, res);
 373   res = internal_unlink(shmname);
 374   CHECK_EQ(0, res);
 375   *flags &= ~(MAP_ANON | MAP_ANONYMOUS);
 376   return fd;
 377 }
 378 #else
 379 int GetNamedMappingFd(const char *name, uptr size, int *flags) {
 380   return -1;
 381 }
 382 #endif
 383
 384 #if SANITIZER_ANDROID
 385 #define PR_SET_VMA 0x53564d41
 386 #define PR_SET_VMA_ANON_NAME 0
 387 void DecorateMapping(uptr addr, uptr size, const char *name) {
 388   if (!common_flags()->decorate_proc_maps || !name)
 389     return;
 390   internal_prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, addr, size, (uptr)name);
 391 }
 392 #else
 393 void DecorateMapping(uptr addr, uptr size, const char *name) {
 394 }
 395 #endif
 396
 397 uptr MmapNamed(void *addr, uptr length, int prot, int flags, const char *name) {
 398   int fd = GetNamedMappingFd(name, length, &flags);
 399   uptr res = internal_mmap(addr, length, prot, flags, fd, 0);
 400   if (!internal_iserror(res))
 401     DecorateMapping(res, length, name);
 402   return res;
 403 }
 404
 405
 406 } // namespace __sanitizer
 407
 408 #endif // SANITIZER_POSIX