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   return (1ULL << 44) - 1;  // 0x00000fffffffffffUL
  86 # elif defined(__aarch64__)
  87   return (1ULL << 39) - 1;
  88 # else
  89   return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
  90 # endif
  91 #else  // SANITIZER_WORDSIZE == 32
  92   uptr res = (1ULL << 32) - 1;  // 0xffffffff;
  93   if (!common_flags()->full_address_space)
  94     res -= GetKernelAreaSize();
  95   CHECK_LT(reinterpret_cast<uptr>(&res), res);
  96   return res;
  97 #endif  // SANITIZER_WORDSIZE
  98 }
  99
 100 void *MmapOrDie(uptr size, const char *mem_type) {
 101   size = RoundUpTo(size, GetPageSizeCached());
 102   uptr res = internal_mmap(0, size,
 103                             PROT_READ | PROT_WRITE,
 104                             MAP_PRIVATE | MAP_ANON, -1, 0);
 105   int reserrno;
 106   if (internal_iserror(res, &reserrno)) {
 107     static int recursion_count;
 108     if (recursion_count) {
 109       // The Report() and CHECK calls below may call mmap recursively and fail.
 110       // If we went into recursion, just die.
 111       RawWrite("ERROR: Failed to mmap\n");
 112       Die();
 113     }
 114     recursion_count++;
 115     Report("ERROR: %s failed to "
 116            "allocate 0x%zx (%zd) bytes of %s (errno: %d)\n",
 117            SanitizerToolName, size, size, mem_type, reserrno);
 118     DumpProcessMap();
 119     CHECK("unable to mmap" && 0);
 120   }
 121   IncreaseTotalMmap(size);
 122   return (void *)res;
 123 }
 124
 125 void UnmapOrDie(void *addr, uptr size) {
 126   if (!addr || !size) return;
 127   uptr res = internal_munmap(addr, size);
 128   if (internal_iserror(res)) {
 129     Report("ERROR: %s failed to deallocate 0x%zx (%zd) bytes at address %p\n",
 130            SanitizerToolName, size, size, addr);
 131     CHECK("unable to unmap" && 0);
 132   }
 133   DecreaseTotalMmap(size);
 134 }
 135
 136 void *MmapNoReserveOrDie(uptr size, const char *mem_type) {
 137   uptr PageSize = GetPageSizeCached();
 138   uptr p = internal_mmap(0,
 139       RoundUpTo(size, PageSize),
 140       PROT_READ | PROT_WRITE,
 141       MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
 142       -1, 0);
 143   int reserrno;
 144   if (internal_iserror(p, &reserrno)) {
 145     Report("ERROR: %s failed to "
 146            "allocate noreserve 0x%zx (%zd) bytes for '%s' (errno: %d)\n",
 147            SanitizerToolName, size, size, mem_type, reserrno);
 148     CHECK("unable to mmap" && 0);
 149   }
 150   IncreaseTotalMmap(size);
 151   return (void *)p;
 152 }
 153
 154 void *MmapFixedNoReserve(uptr fixed_addr, uptr size) {
 155   uptr PageSize = GetPageSizeCached();
 156   uptr p = internal_mmap((void*)(fixed_addr & ~(PageSize - 1)),
 157       RoundUpTo(size, PageSize),
 158       PROT_READ | PROT_WRITE,
 159       MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_NORESERVE,
 160       -1, 0);
 161   int reserrno;
 162   if (internal_iserror(p, &reserrno))
 163     Report("ERROR: %s failed to "
 164            "allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
 165            SanitizerToolName, size, size, fixed_addr, reserrno);
 166   IncreaseTotalMmap(size);
 167   return (void *)p;
 168 }
 169
 170 void *MmapFixedOrDie(uptr fixed_addr, uptr size) {
 171   uptr PageSize = GetPageSizeCached();
 172   uptr p = internal_mmap((void*)(fixed_addr & ~(PageSize - 1)),
 173       RoundUpTo(size, PageSize),
 174       PROT_READ | PROT_WRITE,
 175       MAP_PRIVATE | MAP_ANON | MAP_FIXED,
 176       -1, 0);
 177   int reserrno;
 178   if (internal_iserror(p, &reserrno)) {
 179     Report("ERROR: %s failed to "
 180            "allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
 181            SanitizerToolName, size, size, fixed_addr, reserrno);
 182     CHECK("unable to mmap" && 0);
 183   }
 184   IncreaseTotalMmap(size);
 185   return (void *)p;
 186 }
 187
 188 void *Mprotect(uptr fixed_addr, uptr size) {
 189   return (void *)internal_mmap((void*)fixed_addr, size,
 190                                PROT_NONE,
 191                                MAP_PRIVATE | MAP_ANON | MAP_FIXED |
 192                                MAP_NORESERVE, -1, 0);
 193 }
 194
 195 void *MapFileToMemory(const char *file_name, uptr *buff_size) {
 196   uptr openrv = OpenFile(file_name, false);
 197   CHECK(!internal_iserror(openrv));
 198   fd_t fd = openrv;
 199   uptr fsize = internal_filesize(fd);
 200   CHECK_NE(fsize, (uptr)-1);
 201   CHECK_GT(fsize, 0);
 202   *buff_size = RoundUpTo(fsize, GetPageSizeCached());
 203   uptr map = internal_mmap(0, *buff_size, PROT_READ, MAP_PRIVATE, fd, 0);
 204   return internal_iserror(map) ? 0 : (void *)map;
 205 }
 206
 207 void *MapWritableFileToMemory(void *addr, uptr size, uptr fd, uptr offset) {
 208   uptr flags = MAP_SHARED;
 209   if (addr) flags |= MAP_FIXED;
 210   uptr p = internal_mmap(addr, size, PROT_READ | PROT_WRITE, flags, fd, offset);
 211   if (internal_iserror(p)) {
 212     Printf("could not map writable file (%zd, %zu, %zu): %zd\n", fd, offset,
 213            size, p);
 214     return 0;
 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   uptr start, end;
 233   while (proc_maps.Next(&start, &end,
 234                         /*offset*/0, /*filename*/0, /*filename_size*/0,
 235                         /*protection*/0)) {
 236     if (!IntervalsAreSeparate(start, end, range_start, range_end))
 237       return false;
 238   }
 239   return true;
 240 }
 241
 242 void DumpProcessMap() {
 243   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 244   uptr start, end;
 245   const sptr kBufSize = 4095;
 246   char *filename = (char*)MmapOrDie(kBufSize, __func__);
 247   Report("Process memory map follows:\n");
 248   while (proc_maps.Next(&start, &end, /* file_offset */0,
 249                         filename, kBufSize, /* protection */0)) {
 250     Printf("\t%p-%p\t%s\n", (void*)start, (void*)end, filename);
 251   }
 252   Report("End of process memory map.\n");
 253   UnmapOrDie(filename, kBufSize);
 254 }
 255
 256 const char *GetPwd() {
 257   return GetEnv("PWD");
 258 }
 259
 260 char *FindPathToBinary(const char *name) {
 261   const char *path = GetEnv("PATH");
 262   if (!path)
 263     return 0;
 264   uptr name_len = internal_strlen(name);
 265   InternalScopedBuffer<char> buffer(kMaxPathLength);
 266   const char *beg = path;
 267   while (true) {
 268     const char *end = internal_strchrnul(beg, ':');
 269     uptr prefix_len = end - beg;
 270     if (prefix_len + name_len + 2 <= kMaxPathLength) {
 271       internal_memcpy(buffer.data(), beg, prefix_len);
 272       buffer[prefix_len] = '/';
 273       internal_memcpy(&buffer[prefix_len + 1], name, name_len);
 274       buffer[prefix_len + 1 + name_len] = '\0';
 275       if (FileExists(buffer.data()))
 276         return internal_strdup(buffer.data());
 277     }
 278     if (*end == '\0') break;
 279     beg = end + 1;
 280   }
 281   return 0;
 282 }
 283
 284 void MaybeOpenReportFile() {
 285   if (!log_to_file) return;
 286   uptr pid = internal_getpid();
 287   // If in tracer, use the parent's file.
 288   if (pid == stoptheworld_tracer_pid)
 289     pid = stoptheworld_tracer_ppid;
 290   if (report_fd_pid == pid) return;
 291   InternalScopedBuffer<char> report_path_full(4096);
 292   internal_snprintf(report_path_full.data(), report_path_full.size(),
 293                     "%s.%zu", report_path_prefix, pid);
 294   uptr openrv = OpenFile(report_path_full.data(), true);
 295   if (internal_iserror(openrv)) {
 296     report_fd = kStderrFd;
 297     log_to_file = false;
 298     Report("ERROR: Can't open file: %s\n", report_path_full.data());
 299     Die();
 300   }
 301   if (report_fd != kInvalidFd) {
 302     // We're in the child. Close the parent's log.
 303     internal_close(report_fd);
 304   }
 305   report_fd = openrv;
 306   report_fd_pid = pid;
 307 }
 308
 309 void RawWrite(const char *buffer) {
 310   static const char *kRawWriteError =
 311       "RawWrite can't output requested buffer!\n";
 312   uptr length = (uptr)internal_strlen(buffer);
 313   MaybeOpenReportFile();
 314   if (length != internal_write(report_fd, buffer, length)) {
 315     internal_write(report_fd, kRawWriteError, internal_strlen(kRawWriteError));
 316     Die();
 317   }
 318 }
 319
 320 bool GetCodeRangeForFile(const char *module, uptr *start, uptr *end) {
 321   uptr s, e, off, prot;
 322   InternalScopedString buff(4096);
 323   MemoryMappingLayout proc_maps(/*cache_enabled*/false);
 324   while (proc_maps.Next(&s, &e, &off, buff.data(), buff.size(), &prot)) {
 325     if ((prot & MemoryMappingLayout::kProtectionExecute) != 0
 326         && internal_strcmp(module, buff.data()) == 0) {
 327       *start = s;
 328       *end = e;
 329       return true;
 330     }
 331   }
 332   return false;
 333 }
 334
 335 }  // namespace __sanitizer
 336
 337 #endif  // SANITIZER_POSIX