libsanitizer/sanitizer_common/sanitizer_posix.cc

   1 //===-- sanitizer_posix.cc ------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is shared between AddressSanitizer and ThreadSanitizer
   9 // run-time libraries and implements POSIX-specific functions from
  10 // sanitizer_libc.h.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_platform.h"
  14 #if SANITIZER_POSIX
  15
  16 #include "sanitizer_common.h"
  17 #include "sanitizer_libc.h"
  18 #include "sanitizer_procmaps.h"
  19 #include "sanitizer_stacktrace.h"
  20
  21 #include <sys/mman.h>
  22
  23 #if SANITIZER_LINUX
  24 #include <sys/utsname.h>
  25 #endif
  26
  27 #if SANITIZER_LINUX && !SANITIZER_ANDROID
  28 #include <sys/personality.h>
  29 #endif
  30
  31 namespace __sanitizer {
  32
  33 // ------------- sanitizer_common.h
  34 uptr GetMmapGranularity() {
  35   return GetPageSize();
  36 }
  37
  38 #if SANITIZER_WORDSIZE == 32
  39 // Take care of unusable kernel area in top gigabyte.
  40 static uptr GetKernelAreaSize() {
  41 #if SANITIZER_LINUX
  42   const uptr gbyte = 1UL << 30;
  43
  44   // Firstly check if there are writable segments
  45   // mapped to top gigabyte (e.g. stack).
  46   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
  47   uptr end, prot;
  48   while (proc_maps.Next(/*start*/0, &end,
  49                         /*offset*/0, /*filename*/0,
  50                         /*filename_size*/0, &prot)) {
  51     if ((end >= 3 * gbyte)
  52         && (prot & MemoryMappingLayout::kProtectionWrite) != 0)
  53       return 0;
  54   }
  55
  56 #if !SANITIZER_ANDROID
  57   // Even if nothing is mapped, top Gb may still be accessible
  58   // if we are running on 64-bit kernel.
  59   // Uname may report misleading results if personality type
  60   // is modified (e.g. under schroot) so check this as well.
  61   struct utsname uname_info;
  62   int pers = personality(0xffffffffUL);
  63   if (!(pers & PER_MASK)
  64       && uname(&uname_info) == 0
  65       && internal_strstr(uname_info.machine, "64"))
  66     return 0;
  67 #endif  // SANITIZER_ANDROID
  68
  69   // Top gigabyte is reserved for kernel.
  70   return gbyte;
  71 #else
  72   return 0;
  73 #endif  // SANITIZER_LINUX
  74 }
  75 #endif  // SANITIZER_WORDSIZE == 32
  76
  77 uptr GetMaxVirtualAddress() {
  78 #if SANITIZER_WORDSIZE == 64
  79 # if defined(__powerpc64__)
  80   // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
  81   // We somehow need to figure out which one we are using now and choose
  82   // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
  83   // Note that with 'ulimit -s unlimited' the stack is moved away from the top
  84   // of the address space, so simply checking the stack address is not enough.
  85   // This should (does) work for both PowerPC64 Endian modes.
  86   return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
  87 # elif defined(__aarch64__)
  88   return (1ULL << 39) - 1;
  89 # elif defined(__mips64)
  90   return (1ULL << 40) - 1;
  91 # else
  92   return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
  93 # endif
  94 #else  // SANITIZER_WORDSIZE == 32
  95   uptr res = (1ULL << 32) - 1;  // 0xffffffff;
  96   if (!common_flags()->full_address_space)
  97     res -= GetKernelAreaSize();
  98   CHECK_LT(reinterpret_cast<uptr>(&res), res);
  99   return res;
 100 #endif  // SANITIZER_WORDSIZE
 101 }
 102
 103 void *MmapOrDie(uptr size, const char *mem_type) {
 104   size = RoundUpTo(size, GetPageSizeCached());
 105   uptr res = internal_mmap(0, size,
 106                             PROT_READ | PROT_WRITE,
 107                             MAP_PRIVATE | MAP_ANON, -1, 0);
 108   int reserrno;
 109   if (internal_iserror(res, &reserrno)) {
 110     static int recursion_count;
 111     if (recursion_count) {
 112       // The Report() and CHECK calls below may call mmap recursively and fail.
 113       // If we went into recursion, just die.
 114       RawWrite("ERROR: Failed to mmap\n");
 115       Die();
 116     }
 117     recursion_count++;
 118     Report("ERROR: %s failed to "
 119            "allocate 0x%zx (%zd) bytes of %s (errno: %d)\n",
 120            SanitizerToolName, size, size, mem_type, reserrno);
 121     DumpProcessMap();
 122     CHECK("unable to mmap" && 0);
 123   }
 124   IncreaseTotalMmap(size);
 125   return (void *)res;
 126 }
 127
 128 void UnmapOrDie(void *addr, uptr size) {
 129   if (!addr || !size) return;
 130   uptr res = internal_munmap(addr, size);
 131   if (internal_iserror(res)) {
 132     Report("ERROR: %s failed to deallocate 0x%zx (%zd) bytes at address %p\n",
 133            SanitizerToolName, size, size, addr);
 134     CHECK("unable to unmap" && 0);
 135   }
 136   DecreaseTotalMmap(size);
 137 }
 138
 139 void *MmapNoReserveOrDie(uptr size, const char *mem_type) {
 140   uptr PageSize = GetPageSizeCached();
 141   uptr p = internal_mmap(0,
 142       RoundUpTo(size, PageSize),
 143       PROT_READ | PROT_WRITE,
 144       MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
 145       -1, 0);
 146   int reserrno;
 147   if (internal_iserror(p, &reserrno)) {
 148     Report("ERROR: %s failed to "
 149            "allocate noreserve 0x%zx (%zd) bytes for '%s' (errno: %d)\n",
 150            SanitizerToolName, size, size, mem_type, reserrno);
 151     CHECK("unable to mmap" && 0);
 152   }
 153   IncreaseTotalMmap(size);
 154   return (void *)p;
 155 }
 156
 157 void *MmapFixedNoReserve(uptr fixed_addr, uptr size) {
 158   uptr PageSize = GetPageSizeCached();
 159   uptr p = internal_mmap((void*)(fixed_addr & ~(PageSize - 1)),
 160       RoundUpTo(size, PageSize),
 161       PROT_READ | PROT_WRITE,
 162       MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_NORESERVE,
 163       -1, 0);
 164   int reserrno;
 165   if (internal_iserror(p, &reserrno))
 166     Report("ERROR: %s failed to "
 167            "allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
 168            SanitizerToolName, size, size, fixed_addr, reserrno);
 169   IncreaseTotalMmap(size);
 170   return (void *)p;
 171 }
 172
 173 void *MmapFixedOrDie(uptr fixed_addr, uptr size) {
 174   uptr PageSize = GetPageSizeCached();
 175   uptr p = internal_mmap((void*)(fixed_addr & ~(PageSize - 1)),
 176       RoundUpTo(size, PageSize),
 177       PROT_READ | PROT_WRITE,
 178       MAP_PRIVATE | MAP_ANON | MAP_FIXED,
 179       -1, 0);
 180   int reserrno;
 181   if (internal_iserror(p, &reserrno)) {
 182     Report("ERROR: %s failed to "
 183            "allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
 184            SanitizerToolName, size, size, fixed_addr, reserrno);
 185     CHECK("unable to mmap" && 0);
 186   }
 187   IncreaseTotalMmap(size);
 188   return (void *)p;
 189 }
 190
 191 void *Mprotect(uptr fixed_addr, uptr size) {
 192   return (void *)internal_mmap((void*)fixed_addr, size,
 193                                PROT_NONE,
 194                                MAP_PRIVATE | MAP_ANON | MAP_FIXED |
 195                                MAP_NORESERVE, -1, 0);
 196 }
 197
 198 void *MapFileToMemory(const char *file_name, uptr *buff_size) {
 199   uptr openrv = OpenFile(file_name, false);
 200   CHECK(!internal_iserror(openrv));
 201   fd_t fd = openrv;
 202   uptr fsize = internal_filesize(fd);
 203   CHECK_NE(fsize, (uptr)-1);
 204   CHECK_GT(fsize, 0);
 205   *buff_size = RoundUpTo(fsize, GetPageSizeCached());
 206   uptr map = internal_mmap(0, *buff_size, PROT_READ, MAP_PRIVATE, fd, 0);
 207   return internal_iserror(map) ? 0 : (void *)map;
 208 }
 209
 210 void *MapWritableFileToMemory(void *addr, uptr size, uptr fd, uptr offset) {
 211   uptr flags = MAP_SHARED;
 212   if (addr) flags |= MAP_FIXED;
 213   uptr p = internal_mmap(addr, size, PROT_READ | PROT_WRITE, flags, fd, offset);
 214   if (internal_iserror(p)) {
 215     Printf("could not map writable file (%zd, %zu, %zu): %zd\n", fd, offset,
 216            size, p);
 217     return 0;
 218   }
 219   return (void *)p;
 220 }
 221
 222 static inline bool IntervalsAreSeparate(uptr start1, uptr end1,
 223                                         uptr start2, uptr end2) {
 224   CHECK(start1 <= end1);
 225   CHECK(start2 <= end2);
 226   return (end1 < start2) || (end2 < start1);
 227 }
 228
 229 // FIXME: this is thread-unsafe, but should not cause problems most of the time.
 230 // When the shadow is mapped only a single thread usually exists (plus maybe
 231 // several worker threads on Mac, which aren't expected to map big chunks of
 232 // memory).
 233 bool MemoryRangeIsAvailable(uptr range_start, uptr range_end) {
 234   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 235   uptr start, end;
 236   while (proc_maps.Next(&start, &end,
 237                         /*offset*/0, /*filename*/0, /*filename_size*/0,
 238                         /*protection*/0)) {
 239     if (!IntervalsAreSeparate(start, end, range_start, range_end))
 240       return false;
 241   }
 242   return true;
 243 }
 244
 245 void DumpProcessMap() {
 246   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 247   uptr start, end;
 248   const sptr kBufSize = 4095;
 249   char *filename = (char*)MmapOrDie(kBufSize, __func__);
 250   Report("Process memory map follows:\n");
 251   while (proc_maps.Next(&start, &end, /* file_offset */0,
 252                         filename, kBufSize, /* protection */0)) {
 253     Printf("\t%p-%p\t%s\n", (void*)start, (void*)end, filename);
 254   }
 255   Report("End of process memory map.\n");
 256   UnmapOrDie(filename, kBufSize);
 257 }
 258
 259 const char *GetPwd() {
 260   return GetEnv("PWD");
 261 }
 262
 263 char *FindPathToBinary(const char *name) {
 264   const char *path = GetEnv("PATH");
 265   if (!path)
 266     return 0;
 267   uptr name_len = internal_strlen(name);
 268   InternalScopedBuffer<char> buffer(kMaxPathLength);
 269   const char *beg = path;
 270   while (true) {
 271     const char *end = internal_strchrnul(beg, ':');
 272     uptr prefix_len = end - beg;
 273     if (prefix_len + name_len + 2 <= kMaxPathLength) {
 274       internal_memcpy(buffer.data(), beg, prefix_len);
 275       buffer[prefix_len] = '/';
 276       internal_memcpy(&buffer[prefix_len + 1], name, name_len);
 277       buffer[prefix_len + 1 + name_len] = '\0';
 278       if (FileExists(buffer.data()))
 279         return internal_strdup(buffer.data());
 280     }
 281     if (*end == '\0') break;
 282     beg = end + 1;
 283   }
 284   return 0;
 285 }
 286
 287 void MaybeOpenReportFile() {
 288   if (!log_to_file) return;
 289   uptr pid = internal_getpid();
 290   // If in tracer, use the parent's file.
 291   if (pid == stoptheworld_tracer_pid)
 292     pid = stoptheworld_tracer_ppid;
 293   if (report_fd_pid == pid) return;
 294   InternalScopedBuffer<char> report_path_full(4096);
 295   internal_snprintf(report_path_full.data(), report_path_full.size(),
 296                     "%s.%zu", report_path_prefix, pid);
 297   uptr openrv = OpenFile(report_path_full.data(), true);
 298   if (internal_iserror(openrv)) {
 299     report_fd = kStderrFd;
 300     log_to_file = false;
 301     Report("ERROR: Can't open file: %s\n", report_path_full.data());
 302     Die();
 303   }
 304   if (report_fd != kInvalidFd) {
 305     // We're in the child. Close the parent's log.
 306     internal_close(report_fd);
 307   }
 308   report_fd = openrv;
 309   report_fd_pid = pid;
 310 }
 311
 312 void RawWrite(const char *buffer) {
 313   static const char *kRawWriteError =
 314       "RawWrite can't output requested buffer!\n";
 315   uptr length = (uptr)internal_strlen(buffer);
 316   MaybeOpenReportFile();
 317   if (length != internal_write(report_fd, buffer, length)) {
 318     internal_write(report_fd, kRawWriteError, internal_strlen(kRawWriteError));
 319     Die();
 320   }
 321 }
 322
 323 bool GetCodeRangeForFile(const char *module, uptr *start, uptr *end) {
 324   uptr s, e, off, prot;
 325   InternalScopedString buff(4096);
 326   MemoryMappingLayout proc_maps(/*cache_enabled*/false);
 327   while (proc_maps.Next(&s, &e, &off, buff.data(), buff.size(), &prot)) {
 328     if ((prot & MemoryMappingLayout::kProtectionExecute) != 0
 329         && internal_strcmp(module, buff.data()) == 0) {
 330       *start = s;
 331       *end = e;
 332       return true;
 333     }
 334   }
 335   return false;
 336 }
 337
 338 }  // namespace __sanitizer
 339
 340 #endif  // SANITIZER_POSIX