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
  13 #include "sanitizer_allocator.h"
  14
  15 #include "sanitizer_allocator_internal.h"
  16 #include "sanitizer_atomic.h"
  17 #include "sanitizer_common.h"
  18
  19 namespace __sanitizer {
  20
  21 // ThreadSanitizer for Go uses libc malloc/free.
  22 #if SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
  23 # if SANITIZER_LINUX && !SANITIZER_ANDROID
  24 extern "C" void *__libc_malloc(uptr size);
  25 #  if !SANITIZER_GO
  26 extern "C" void *__libc_memalign(uptr alignment, uptr size);
  27 #  endif
  28 extern "C" void *__libc_realloc(void *ptr, uptr size);
  29 extern "C" void __libc_free(void *ptr);
  30 # else
  31 #  include <stdlib.h>
  32 #  define __libc_malloc malloc
  33 #  if !SANITIZER_GO
  34 static void *__libc_memalign(uptr alignment, uptr size) {
  35   void *p;
  36   uptr error = posix_memalign(&p, alignment, size);
  37   if (error) return nullptr;
  38   return p;
  39 }
  40 #  endif
  41 #  define __libc_realloc realloc
  42 #  define __libc_free free
  43 # endif
  44
  45 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
  46                               uptr alignment) {
  47   (void)cache;
  48 #if !SANITIZER_GO
  49   if (alignment == 0)
  50     return __libc_malloc(size);
  51   else
  52     return __libc_memalign(alignment, size);
  53 #else
  54   // Windows does not provide __libc_memalign/posix_memalign. It provides
  55   // __aligned_malloc, but the allocated blocks can't be passed to free,
  56   // they need to be passed to __aligned_free. InternalAlloc interface does
  57   // not account for such requirement. Alignemnt does not seem to be used
  58   // anywhere in runtime, so just call __libc_malloc for now.
  59   DCHECK_EQ(alignment, 0);
  60   return __libc_malloc(size);
  61 #endif
  62 }
  63
  64 static void *RawInternalRealloc(void *ptr, uptr size,
  65                                 InternalAllocatorCache *cache) {
  66   (void)cache;
  67   return __libc_realloc(ptr, size);
  68 }
  69
  70 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
  71   (void)cache;
  72   __libc_free(ptr);
  73 }
  74
  75 InternalAllocator *internal_allocator() {
  76   return 0;
  77 }
  78
  79 #else  // SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
  80
  81 static ALIGNED(64) char internal_alloc_placeholder[sizeof(InternalAllocator)];
  82 static atomic_uint8_t internal_allocator_initialized;
  83 static StaticSpinMutex internal_alloc_init_mu;
  84
  85 static InternalAllocatorCache internal_allocator_cache;
  86 static StaticSpinMutex internal_allocator_cache_mu;
  87
  88 InternalAllocator *internal_allocator() {
  89   InternalAllocator *internal_allocator_instance =
  90       reinterpret_cast<InternalAllocator *>(&internal_alloc_placeholder);
  91   if (atomic_load(&internal_allocator_initialized, memory_order_acquire) == 0) {
  92     SpinMutexLock l(&internal_alloc_init_mu);
  93     if (atomic_load(&internal_allocator_initialized, memory_order_relaxed) ==
  94         0) {
  95       internal_allocator_instance->Init(/* may_return_null*/ false);
  96       atomic_store(&internal_allocator_initialized, 1, memory_order_release);
  97     }
  98   }
  99   return internal_allocator_instance;
 100 }
 101
 102 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
 103                               uptr alignment) {
 104   if (alignment == 0) alignment = 8;
 105   if (cache == 0) {
 106     SpinMutexLock l(&internal_allocator_cache_mu);
 107     return internal_allocator()->Allocate(&internal_allocator_cache, size,
 108                                           alignment, false);
 109   }
 110   return internal_allocator()->Allocate(cache, size, alignment, false);
 111 }
 112
 113 static void *RawInternalRealloc(void *ptr, uptr size,
 114                                 InternalAllocatorCache *cache) {
 115   uptr alignment = 8;
 116   if (cache == 0) {
 117     SpinMutexLock l(&internal_allocator_cache_mu);
 118     return internal_allocator()->Reallocate(&internal_allocator_cache, ptr,
 119                                             size, alignment);
 120   }
 121   return internal_allocator()->Reallocate(cache, ptr, size, alignment);
 122 }
 123
 124 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
 125   if (!cache) {
 126     SpinMutexLock l(&internal_allocator_cache_mu);
 127     return internal_allocator()->Deallocate(&internal_allocator_cache, ptr);
 128   }
 129   internal_allocator()->Deallocate(cache, ptr);
 130 }
 131
 132 #endif  // SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
 133
 134 const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
 135
 136 void *InternalAlloc(uptr size, InternalAllocatorCache *cache, uptr alignment) {
 137   if (size + sizeof(u64) < size)
 138     return nullptr;
 139   void *p = RawInternalAlloc(size + sizeof(u64), cache, alignment);
 140   if (!p)
 141     return nullptr;
 142   ((u64*)p)[0] = kBlockMagic;
 143   return (char*)p + sizeof(u64);
 144 }
 145
 146 void *InternalRealloc(void *addr, uptr size, InternalAllocatorCache *cache) {
 147   if (!addr)
 148     return InternalAlloc(size, cache);
 149   if (size + sizeof(u64) < size)
 150     return nullptr;
 151   addr = (char*)addr - sizeof(u64);
 152   size = size + sizeof(u64);
 153   CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
 154   void *p = RawInternalRealloc(addr, size, cache);
 155   if (!p)
 156     return nullptr;
 157   return (char*)p + sizeof(u64);
 158 }
 159
 160 void *InternalCalloc(uptr count, uptr size, InternalAllocatorCache *cache) {
 161   if (CallocShouldReturnNullDueToOverflow(count, size))
 162     return internal_allocator()->ReturnNullOrDieOnBadRequest();
 163   void *p = InternalAlloc(count * size, cache);
 164   if (p) internal_memset(p, 0, count * size);
 165   return p;
 166 }
 167
 168 void InternalFree(void *addr, InternalAllocatorCache *cache) {
 169   if (!addr)
 170     return;
 171   addr = (char*)addr - sizeof(u64);
 172   CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
 173   ((u64*)addr)[0] = 0;
 174   RawInternalFree(addr, cache);
 175 }
 176
 177 // LowLevelAllocator
 178 static LowLevelAllocateCallback low_level_alloc_callback;
 179
 180 void *LowLevelAllocator::Allocate(uptr size) {
 181   // Align allocation size.
 182   size = RoundUpTo(size, 8);
 183   if (allocated_end_ - allocated_current_ < (sptr)size) {
 184     uptr size_to_allocate = Max(size, GetPageSizeCached());
 185     allocated_current_ =
 186         (char*)MmapOrDie(size_to_allocate, __func__);
 187     allocated_end_ = allocated_current_ + size_to_allocate;
 188     if (low_level_alloc_callback) {
 189       low_level_alloc_callback((uptr)allocated_current_,
 190                                size_to_allocate);
 191     }
 192   }
 193   CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
 194   void *res = allocated_current_;
 195   allocated_current_ += size;
 196   return res;
 197 }
 198
 199 void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
 200   low_level_alloc_callback = callback;
 201 }
 202
 203 bool CallocShouldReturnNullDueToOverflow(uptr size, uptr n) {
 204   if (!size) return false;
 205   uptr max = (uptr)-1L;
 206   return (max / size) < n;
 207 }
 208
 209 static atomic_uint8_t reporting_out_of_memory = {0};
 210
 211 bool IsReportingOOM() { return atomic_load_relaxed(&reporting_out_of_memory); }
 212
 213 void NORETURN ReportAllocatorCannotReturnNull(bool out_of_memory) {
 214   if (out_of_memory) atomic_store_relaxed(&reporting_out_of_memory, 1);
 215   Report("%s's allocator is terminating the process instead of returning 0\n",
 216          SanitizerToolName);
 217   Report("If you don't like this behavior set allocator_may_return_null=1\n");
 218   CHECK(0);
 219   Die();
 220 }
 221
 222 } // namespace __sanitizer