libsanitizer/sanitizer_common/sanitizer_allocator.cc

   1 //===-- sanitizer_allocator.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.
  10 // This allocator that is used inside run-times.
  11 //===----------------------------------------------------------------------===//
  12 #include "sanitizer_common.h"
  13
  14 // FIXME: We should probably use more low-level allocator that would
  15 // mmap some pages and split them into chunks to fulfill requests.
  16 #if defined(__linux__) && !defined(__ANDROID__)
  17 extern "C" void *__libc_malloc(__sanitizer::uptr size);
  18 extern "C" void __libc_free(void *ptr);
  19 # define LIBC_MALLOC __libc_malloc
  20 # define LIBC_FREE __libc_free
  21 #else  // __linux__ && !ANDROID
  22 # include <stdlib.h>
  23 # define LIBC_MALLOC malloc
  24 # define LIBC_FREE free
  25 #endif  // __linux__ && !ANDROID
  26
  27 namespace __sanitizer {
  28
  29 const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
  30
  31 void *InternalAlloc(uptr size) {
  32   if (size + sizeof(u64) < size)
  33     return 0;
  34   void *p = LIBC_MALLOC(size + sizeof(u64));
  35   if (p == 0)
  36     return 0;
  37   ((u64*)p)[0] = kBlockMagic;
  38   return (char*)p + sizeof(u64);
  39 }
  40
  41 void InternalFree(void *addr) {
  42   if (addr == 0)
  43     return;
  44   addr = (char*)addr - sizeof(u64);
  45   CHECK_EQ(((u64*)addr)[0], kBlockMagic);
  46   ((u64*)addr)[0] = 0;
  47   LIBC_FREE(addr);
  48 }
  49
  50 // LowLevelAllocator
  51 static LowLevelAllocateCallback low_level_alloc_callback;
  52
  53 void *LowLevelAllocator::Allocate(uptr size) {
  54   // Align allocation size.
  55   size = RoundUpTo(size, 8);
  56   if (allocated_end_ - allocated_current_ < (sptr)size) {
  57     uptr size_to_allocate = Max(size, GetPageSizeCached());
  58     allocated_current_ =
  59         (char*)MmapOrDie(size_to_allocate, __FUNCTION__);
  60     allocated_end_ = allocated_current_ + size_to_allocate;
  61     if (low_level_alloc_callback) {
  62       low_level_alloc_callback((uptr)allocated_current_,
  63                                size_to_allocate);
  64     }
  65   }
  66   CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
  67   void *res = allocated_current_;
  68   allocated_current_ += size;
  69   return res;
  70 }
  71
  72 void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
  73   low_level_alloc_callback = callback;
  74 }
  75
  76 bool CallocShouldReturnNullDueToOverflow(uptr size, uptr n) {
  77   if (!size) return false;
  78   uptr max = (uptr)-1L;
  79   return (max / size) < n;
  80 }
  81
  82 }  // namespace __sanitizer