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