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__) || defined(__aarch64__)
  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   // Similarly, aarch64 has multiple address space layouts: 39, 42 and 47-bit.
  87   return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
  88 # elif defined(__mips64)
  89   return (1ULL << 40) - 1;
  90 # else
  91   return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
  92 # endif
  93 #else  // SANITIZER_WORDSIZE == 32
  94   uptr res = (1ULL << 32) - 1;  // 0xffffffff;
  95   if (!common_flags()->full_address_space)
  96     res -= GetKernelAreaSize();
  97   CHECK_LT(reinterpret_cast<uptr>(&res), res);
  98   return res;
  99 #endif  // SANITIZER_WORDSIZE
 100 }
 101
 102 void *MmapOrDie(uptr size, const char *mem_type) {
 103   size = RoundUpTo(size, GetPageSizeCached());
 104   uptr res = internal_mmap(0, size,
 105                             PROT_READ | PROT_WRITE,
 106                             MAP_PRIVATE | MAP_ANON, -1, 0);
 107   int reserrno;
 108   if (internal_iserror(res, &reserrno)) {
 109     static int recursion_count;
 110     if (recursion_count) {
 111       // The Report() and CHECK calls below may call mmap recursively and fail.
 112       // If we went into recursion, just die.
 113       RawWrite("ERROR: Failed to mmap\n");
 114       Die();
 115     }
 116     recursion_count++;
 117     Report("ERROR: %s failed to "
 118            "allocate 0x%zx (%zd) bytes of %s (errno: %d)\n",
 119            SanitizerToolName, size, size, mem_type, reserrno);
 120     DumpProcessMap();
 121     CHECK("unable to mmap" && 0);
 122   }
 123   IncreaseTotalMmap(size);
 124   return (void *)res;
 125 }
 126
 127 void UnmapOrDie(void *addr, uptr size) {
 128   if (!addr || !size) return;
 129   uptr res = internal_munmap(addr, size);
 130   if (internal_iserror(res)) {
 131     Report("ERROR: %s failed to deallocate 0x%zx (%zd) bytes at address %p\n",
 132            SanitizerToolName, size, size, addr);
 133     CHECK("unable to unmap" && 0);
 134   }
 135   DecreaseTotalMmap(size);
 136 }
 137
 138 void *MmapNoReserveOrDie(uptr size, const char *mem_type) {
 139   uptr PageSize = GetPageSizeCached();
 140   uptr p = internal_mmap(0,
 141       RoundUpTo(size, PageSize),
 142       PROT_READ | PROT_WRITE,
 143       MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
 144       -1, 0);
 145   int reserrno;
 146   if (internal_iserror(p, &reserrno)) {
 147     Report("ERROR: %s failed to "
 148            "allocate noreserve 0x%zx (%zd) bytes for '%s' (errno: %d)\n",
 149            SanitizerToolName, size, size, mem_type, reserrno);
 150     CHECK("unable to mmap" && 0);
 151   }
 152   IncreaseTotalMmap(size);
 153   return (void *)p;
 154 }
 155
 156 void *MmapFixedNoReserve(uptr fixed_addr, uptr size) {
 157   uptr PageSize = GetPageSizeCached();
 158   uptr p = internal_mmap((void*)(fixed_addr & ~(PageSize - 1)),
 159       RoundUpTo(size, PageSize),
 160       PROT_READ | PROT_WRITE,
 161       MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_NORESERVE,
 162       -1, 0);
 163   int reserrno;
 164   if (internal_iserror(p, &reserrno))
 165     Report("ERROR: %s failed to "
 166            "allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
 167            SanitizerToolName, size, size, fixed_addr, reserrno);
 168   IncreaseTotalMmap(size);
 169   return (void *)p;
 170 }
 171
 172 void *MmapFixedOrDie(uptr fixed_addr, uptr size) {
 173   uptr PageSize = GetPageSizeCached();
 174   uptr p = internal_mmap((void*)(fixed_addr & ~(PageSize - 1)),
 175       RoundUpTo(size, PageSize),
 176       PROT_READ | PROT_WRITE,
 177       MAP_PRIVATE | MAP_ANON | MAP_FIXED,
 178       -1, 0);
 179   int reserrno;
 180   if (internal_iserror(p, &reserrno)) {
 181     Report("ERROR: %s failed to "
 182            "allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
 183            SanitizerToolName, size, size, fixed_addr, reserrno);
 184     CHECK("unable to mmap" && 0);
 185   }
 186   IncreaseTotalMmap(size);
 187   return (void *)p;
 188 }
 189
 190 void *Mprotect(uptr fixed_addr, uptr size) {
 191   return (void *)internal_mmap((void*)fixed_addr, size,
 192                                PROT_NONE,
 193                                MAP_PRIVATE | MAP_ANON | MAP_FIXED |
 194                                MAP_NORESERVE, -1, 0);
 195 }
 196
 197 void *MapFileToMemory(const char *file_name, uptr *buff_size) {
 198   uptr openrv = OpenFile(file_name, false);
 199   CHECK(!internal_iserror(openrv));
 200   fd_t fd = openrv;
 201   uptr fsize = internal_filesize(fd);
 202   CHECK_NE(fsize, (uptr)-1);
 203   CHECK_GT(fsize, 0);
 204   *buff_size = RoundUpTo(fsize, GetPageSizeCached());
 205   uptr map = internal_mmap(0, *buff_size, PROT_READ, MAP_PRIVATE, fd, 0);
 206   return internal_iserror(map) ? 0 : (void *)map;
 207 }
 208
 209 void *MapWritableFileToMemory(void *addr, uptr size, uptr fd, uptr offset) {
 210   uptr flags = MAP_SHARED;
 211   if (addr) flags |= MAP_FIXED;
 212   uptr p = internal_mmap(addr, size, PROT_READ | PROT_WRITE, flags, fd, offset);
 213   if (internal_iserror(p)) {
 214     Printf("could not map writable file (%zd, %zu, %zu): %zd\n", fd, offset,
 215            size, p);
 216     return 0;
 217   }
 218   return (void *)p;
 219 }
 220
 221 static inline bool IntervalsAreSeparate(uptr start1, uptr end1,
 222                                         uptr start2, uptr end2) {
 223   CHECK(start1 <= end1);
 224   CHECK(start2 <= end2);
 225   return (end1 < start2) || (end2 < start1);
 226 }
 227
 228 // FIXME: this is thread-unsafe, but should not cause problems most of the time.
 229 // When the shadow is mapped only a single thread usually exists (plus maybe
 230 // several worker threads on Mac, which aren't expected to map big chunks of
 231 // memory).
 232 bool MemoryRangeIsAvailable(uptr range_start, uptr range_end) {
 233   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 234   uptr start, end;
 235   while (proc_maps.Next(&start, &end,
 236                         /*offset*/0, /*filename*/0, /*filename_size*/0,
 237                         /*protection*/0)) {
 238     if (!IntervalsAreSeparate(start, end, range_start, range_end))
 239       return false;
 240   }
 241   return true;
 242 }
 243
 244 void DumpProcessMap() {
 245   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 246   uptr start, end;
 247   const sptr kBufSize = 4095;
 248   char *filename = (char*)MmapOrDie(kBufSize, __func__);
 249   Report("Process memory map follows:\n");
 250   while (proc_maps.Next(&start, &end, /* file_offset */0,
 251                         filename, kBufSize, /* protection */0)) {
 252     Printf("\t%p-%p\t%s\n", (void*)start, (void*)end, filename);
 253   }
 254   Report("End of process memory map.\n");
 255   UnmapOrDie(filename, kBufSize);
 256 }
 257
 258 const char *GetPwd() {
 259   return GetEnv("PWD");
 260 }
 261
 262 char *FindPathToBinary(const char *name) {
 263   const char *path = GetEnv("PATH");
 264   if (!path)
 265     return 0;
 266   uptr name_len = internal_strlen(name);
 267   InternalScopedBuffer<char> buffer(kMaxPathLength);
 268   const char *beg = path;
 269   while (true) {
 270     const char *end = internal_strchrnul(beg, ':');
 271     uptr prefix_len = end - beg;
 272     if (prefix_len + name_len + 2 <= kMaxPathLength) {
 273       internal_memcpy(buffer.data(), beg, prefix_len);
 274       buffer[prefix_len] = '/';
 275       internal_memcpy(&buffer[prefix_len + 1], name, name_len);
 276       buffer[prefix_len + 1 + name_len] = '\0';
 277       if (FileExists(buffer.data()))
 278         return internal_strdup(buffer.data());
 279     }
 280     if (*end == '\0') break;
 281     beg = end + 1;
 282   }
 283   return 0;
 284 }
 285
 286 void MaybeOpenReportFile() {
 287   if (!log_to_file) return;
 288   uptr pid = internal_getpid();
 289   // If in tracer, use the parent's file.
 290   if (pid == stoptheworld_tracer_pid)
 291     pid = stoptheworld_tracer_ppid;
 292   if (report_fd_pid == pid) return;
 293   InternalScopedBuffer<char> report_path_full(4096);
 294   internal_snprintf(report_path_full.data(), report_path_full.size(),
 295                     "%s.%zu", report_path_prefix, pid);
 296   uptr openrv = OpenFile(report_path_full.data(), true);
 297   if (internal_iserror(openrv)) {
 298     report_fd = kStderrFd;
 299     log_to_file = false;
 300     Report("ERROR: Can't open file: %s\n", report_path_full.data());
 301     Die();
 302   }
 303   if (report_fd != kInvalidFd) {
 304     // We're in the child. Close the parent's log.
 305     internal_close(report_fd);
 306   }
 307   report_fd = openrv;
 308   report_fd_pid = pid;
 309 }
 310
 311 void RawWrite(const char *buffer) {
 312   static const char *kRawWriteError =
 313       "RawWrite can't output requested buffer!\n";
 314   uptr length = (uptr)internal_strlen(buffer);
 315   MaybeOpenReportFile();
 316   if (length != internal_write(report_fd, buffer, length)) {
 317     internal_write(report_fd, kRawWriteError, internal_strlen(kRawWriteError));
 318     Die();
 319   }
 320 }
 321
 322 bool GetCodeRangeForFile(const char *module, uptr *start, uptr *end) {
 323   uptr s, e, off, prot;
 324   InternalScopedString buff(4096);
 325   MemoryMappingLayout proc_maps(/*cache_enabled*/false);
 326   while (proc_maps.Next(&s, &e, &off, buff.data(), buff.size(), &prot)) {
 327     if ((prot & MemoryMappingLayout::kProtectionExecute) != 0
 328         && internal_strcmp(module, buff.data()) == 0) {
 329       *start = s;
 330       *end = e;
 331       return true;
 332     }
 333   }
 334   return false;
 335 }
 336
 337 }  // namespace __sanitizer
 338
 339 #endif  // SANITIZER_POSIX