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 is used inside run-times.
  11 //===----------------------------------------------------------------------===//
  12 #include "sanitizer_allocator.h"
  13 #include "sanitizer_allocator_internal.h"
  14 #include "sanitizer_common.h"
  15 #include "sanitizer_flags.h"
  16
  17 namespace __sanitizer {
  18
  19 // ThreadSanitizer for Go uses libc malloc/free.
  20 #if defined(SANITIZER_GO) || defined(SANITIZER_USE_MALLOC)
  21 # if SANITIZER_LINUX && !SANITIZER_ANDROID
  22 extern "C" void *__libc_malloc(uptr size);
  23 extern "C" void __libc_free(void *ptr);
  24 #  define LIBC_MALLOC __libc_malloc
  25 #  define LIBC_FREE __libc_free
  26 # else
  27 #  include <stdlib.h>
  28 #  define LIBC_MALLOC malloc
  29 #  define LIBC_FREE free
  30 # endif
  31
  32 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache) {
  33   (void)cache;
  34   return LIBC_MALLOC(size);
  35 }
  36
  37 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
  38   (void)cache;
  39   LIBC_FREE(ptr);
  40 }
  41
  42 InternalAllocator *internal_allocator() {
  43   return 0;
  44 }
  45
  46 #else  // SANITIZER_GO
  47
  48 static ALIGNED(64) char internal_alloc_placeholder[sizeof(InternalAllocator)];
  49 static atomic_uint8_t internal_allocator_initialized;
  50 static StaticSpinMutex internal_alloc_init_mu;
  51
  52 static InternalAllocatorCache internal_allocator_cache;
  53 static StaticSpinMutex internal_allocator_cache_mu;
  54
  55 InternalAllocator *internal_allocator() {
  56   InternalAllocator *internal_allocator_instance =
  57       reinterpret_cast<InternalAllocator *>(&internal_alloc_placeholder);
  58   if (atomic_load(&internal_allocator_initialized, memory_order_acquire) == 0) {
  59     SpinMutexLock l(&internal_alloc_init_mu);
  60     if (atomic_load(&internal_allocator_initialized, memory_order_relaxed) ==
  61         0) {
  62       internal_allocator_instance->Init();
  63       atomic_store(&internal_allocator_initialized, 1, memory_order_release);
  64     }
  65   }
  66   return internal_allocator_instance;
  67 }
  68
  69 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache) {
  70   if (cache == 0) {
  71     SpinMutexLock l(&internal_allocator_cache_mu);
  72     return internal_allocator()->Allocate(&internal_allocator_cache, size, 8,
  73                                           false);
  74   }
  75   return internal_allocator()->Allocate(cache, size, 8, false);
  76 }
  77
  78 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
  79   if (cache == 0) {
  80     SpinMutexLock l(&internal_allocator_cache_mu);
  81     return internal_allocator()->Deallocate(&internal_allocator_cache, ptr);
  82   }
  83   internal_allocator()->Deallocate(cache, ptr);
  84 }
  85
  86 #endif  // SANITIZER_GO
  87
  88 const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
  89
  90 void *InternalAlloc(uptr size, InternalAllocatorCache *cache) {
  91   if (size + sizeof(u64) < size)
  92     return 0;
  93   void *p = RawInternalAlloc(size + sizeof(u64), cache);
  94   if (p == 0)
  95     return 0;
  96   ((u64*)p)[0] = kBlockMagic;
  97   return (char*)p + sizeof(u64);
  98 }
  99
 100 void InternalFree(void *addr, InternalAllocatorCache *cache) {
 101   if (addr == 0)
 102     return;
 103   addr = (char*)addr - sizeof(u64);
 104   CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
 105   ((u64*)addr)[0] = 0;
 106   RawInternalFree(addr, cache);
 107 }
 108
 109 // LowLevelAllocator
 110 static LowLevelAllocateCallback low_level_alloc_callback;
 111
 112 void *LowLevelAllocator::Allocate(uptr size) {
 113   // Align allocation size.
 114   size = RoundUpTo(size, 8);
 115   if (allocated_end_ - allocated_current_ < (sptr)size) {
 116     uptr size_to_allocate = Max(size, GetPageSizeCached());
 117     allocated_current_ =
 118         (char*)MmapOrDie(size_to_allocate, __func__);
 119     allocated_end_ = allocated_current_ + size_to_allocate;
 120     if (low_level_alloc_callback) {
 121       low_level_alloc_callback((uptr)allocated_current_,
 122                                size_to_allocate);
 123     }
 124   }
 125   CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
 126   void *res = allocated_current_;
 127   allocated_current_ += size;
 128   return res;
 129 }
 130
 131 void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
 132   low_level_alloc_callback = callback;
 133 }
 134
 135 bool CallocShouldReturnNullDueToOverflow(uptr size, uptr n) {
 136   if (!size) return false;
 137   uptr max = (uptr)-1L;
 138   return (max / size) < n;
 139 }
 140
 141 void *AllocatorReturnNull() {
 142   if (common_flags()->allocator_may_return_null)
 143     return 0;
 144   Report("%s's allocator is terminating the process instead of returning 0\n",
 145          SanitizerToolName);
 146   Report("If you don't like this behavior set allocator_may_return_null=1\n");
 147   CHECK(0);
 148   return 0;
 149 }
 150
 151 }  // namespace __sanitizer