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_checks.h"
  16 #include "sanitizer_allocator_internal.h"
  17 #include "sanitizer_atomic.h"
  18 #include "sanitizer_common.h"
  19
  20 namespace __sanitizer {
  21
  22 // ThreadSanitizer for Go uses libc malloc/free.
  23 #if SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
  24 # if SANITIZER_LINUX && !SANITIZER_ANDROID
  25 extern "C" void *__libc_malloc(uptr size);
  26 #  if !SANITIZER_GO
  27 extern "C" void *__libc_memalign(uptr alignment, uptr size);
  28 #  endif
  29 extern "C" void *__libc_realloc(void *ptr, uptr size);
  30 extern "C" void __libc_free(void *ptr);
  31 # else
  32 #  include <stdlib.h>
  33 #  define __libc_malloc malloc
  34 #  if !SANITIZER_GO
  35 static void *__libc_memalign(uptr alignment, uptr size) {
  36   void *p;
  37   uptr error = posix_memalign(&p, alignment, size);
  38   if (error) return nullptr;
  39   return p;
  40 }
  41 #  endif
  42 #  define __libc_realloc realloc
  43 #  define __libc_free free
  44 # endif
  45
  46 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
  47                               uptr alignment) {
  48   (void)cache;
  49 #if !SANITIZER_GO
  50   if (alignment == 0)
  51     return __libc_malloc(size);
  52   else
  53     return __libc_memalign(alignment, size);
  54 #else
  55   // Windows does not provide __libc_memalign/posix_memalign. It provides
  56   // __aligned_malloc, but the allocated blocks can't be passed to free,
  57   // they need to be passed to __aligned_free. InternalAlloc interface does
  58   // not account for such requirement. Alignemnt does not seem to be used
  59   // anywhere in runtime, so just call __libc_malloc for now.
  60   DCHECK_EQ(alignment, 0);
  61   return __libc_malloc(size);
  62 #endif
  63 }
  64
  65 static void *RawInternalRealloc(void *ptr, uptr size,
  66                                 InternalAllocatorCache *cache) {
  67   (void)cache;
  68   return __libc_realloc(ptr, size);
  69 }
  70
  71 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
  72   (void)cache;
  73   __libc_free(ptr);
  74 }
  75
  76 InternalAllocator *internal_allocator() {
  77   return 0;
  78 }
  79
  80 #else  // SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
  81
  82 static ALIGNED(64) char internal_alloc_placeholder[sizeof(InternalAllocator)];
  83 static atomic_uint8_t internal_allocator_initialized;
  84 static StaticSpinMutex internal_alloc_init_mu;
  85
  86 static InternalAllocatorCache internal_allocator_cache;
  87 static StaticSpinMutex internal_allocator_cache_mu;
  88
  89 InternalAllocator *internal_allocator() {
  90   InternalAllocator *internal_allocator_instance =
  91       reinterpret_cast<InternalAllocator *>(&internal_alloc_placeholder);
  92   if (atomic_load(&internal_allocator_initialized, memory_order_acquire) == 0) {
  93     SpinMutexLock l(&internal_alloc_init_mu);
  94     if (atomic_load(&internal_allocator_initialized, memory_order_relaxed) ==
  95         0) {
  96       internal_allocator_instance->Init(kReleaseToOSIntervalNever);
  97       atomic_store(&internal_allocator_initialized, 1, memory_order_release);
  98     }
  99   }
 100   return internal_allocator_instance;
 101 }
 102
 103 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
 104                               uptr alignment) {
 105   if (alignment == 0) alignment = 8;
 106   if (cache == 0) {
 107     SpinMutexLock l(&internal_allocator_cache_mu);
 108     return internal_allocator()->Allocate(&internal_allocator_cache, size,
 109                                           alignment);
 110   }
 111   return internal_allocator()->Allocate(cache, size, alignment);
 112 }
 113
 114 static void *RawInternalRealloc(void *ptr, uptr size,
 115                                 InternalAllocatorCache *cache) {
 116   uptr alignment = 8;
 117   if (cache == 0) {
 118     SpinMutexLock l(&internal_allocator_cache_mu);
 119     return internal_allocator()->Reallocate(&internal_allocator_cache, ptr,
 120                                             size, alignment);
 121   }
 122   return internal_allocator()->Reallocate(cache, ptr, size, alignment);
 123 }
 124
 125 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
 126   if (!cache) {
 127     SpinMutexLock l(&internal_allocator_cache_mu);
 128     return internal_allocator()->Deallocate(&internal_allocator_cache, ptr);
 129   }
 130   internal_allocator()->Deallocate(cache, ptr);
 131 }
 132
 133 #endif  // SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
 134
 135 const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
 136
 137 void *InternalAlloc(uptr size, InternalAllocatorCache *cache, uptr alignment) {
 138   if (size + sizeof(u64) < size)
 139     return nullptr;
 140   void *p = RawInternalAlloc(size + sizeof(u64), cache, alignment);
 141   if (!p)
 142     return nullptr;
 143   ((u64*)p)[0] = kBlockMagic;
 144   return (char*)p + sizeof(u64);
 145 }
 146
 147 void *InternalRealloc(void *addr, uptr size, InternalAllocatorCache *cache) {
 148   if (!addr)
 149     return InternalAlloc(size, cache);
 150   if (size + sizeof(u64) < size)
 151     return nullptr;
 152   addr = (char*)addr - sizeof(u64);
 153   size = size + sizeof(u64);
 154   CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
 155   void *p = RawInternalRealloc(addr, size, cache);
 156   if (!p)
 157     return nullptr;
 158   return (char*)p + sizeof(u64);
 159 }
 160
 161 void *InternalCalloc(uptr count, uptr size, InternalAllocatorCache *cache) {
 162   if (UNLIKELY(CheckForCallocOverflow(count, size)))
 163     return InternalAllocator::FailureHandler::OnBadRequest();
 164   void *p = InternalAlloc(count * size, cache);
 165   if (p) internal_memset(p, 0, count * size);
 166   return p;
 167 }
 168
 169 void InternalFree(void *addr, InternalAllocatorCache *cache) {
 170   if (!addr)
 171     return;
 172   addr = (char*)addr - sizeof(u64);
 173   CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
 174   ((u64*)addr)[0] = 0;
 175   RawInternalFree(addr, cache);
 176 }
 177
 178 // LowLevelAllocator
 179 static LowLevelAllocateCallback low_level_alloc_callback;
 180
 181 void *LowLevelAllocator::Allocate(uptr size) {
 182   // Align allocation size.
 183   size = RoundUpTo(size, 8);
 184   if (allocated_end_ - allocated_current_ < (sptr)size) {
 185     uptr size_to_allocate = Max(size, GetPageSizeCached());
 186     allocated_current_ =
 187         (char*)MmapOrDie(size_to_allocate, __func__);
 188     allocated_end_ = allocated_current_ + size_to_allocate;
 189     if (low_level_alloc_callback) {
 190       low_level_alloc_callback((uptr)allocated_current_,
 191                                size_to_allocate);
 192     }
 193   }
 194   CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
 195   void *res = allocated_current_;
 196   allocated_current_ += size;
 197   return res;
 198 }
 199
 200 void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
 201   low_level_alloc_callback = callback;
 202 }
 203
 204 static atomic_uint8_t allocator_out_of_memory = {0};
 205 static atomic_uint8_t allocator_may_return_null = {0};
 206
 207 bool IsAllocatorOutOfMemory() {
 208   return atomic_load_relaxed(&allocator_out_of_memory);
 209 }
 210
 211 // Prints error message and kills the program.
 212 void NORETURN ReportAllocatorCannotReturnNull() {
 213   Report("%s's allocator is terminating the process instead of returning 0\n",
 214          SanitizerToolName);
 215   Report("If you don't like this behavior set allocator_may_return_null=1\n");
 216   CHECK(0);
 217   Die();
 218 }
 219
 220 bool AllocatorMayReturnNull() {
 221   return atomic_load(&allocator_may_return_null, memory_order_relaxed);
 222 }
 223
 224 void SetAllocatorMayReturnNull(bool may_return_null) {
 225   atomic_store(&allocator_may_return_null, may_return_null,
 226                memory_order_relaxed);
 227 }
 228
 229 void *ReturnNullOrDieOnFailure::OnBadRequest() {
 230   if (AllocatorMayReturnNull())
 231     return nullptr;
 232   ReportAllocatorCannotReturnNull();
 233 }
 234
 235 void *ReturnNullOrDieOnFailure::OnOOM() {
 236   atomic_store_relaxed(&allocator_out_of_memory, 1);
 237   if (AllocatorMayReturnNull())
 238     return nullptr;
 239   ReportAllocatorCannotReturnNull();
 240 }
 241
 242 void NORETURN *DieOnFailure::OnBadRequest() {
 243   ReportAllocatorCannotReturnNull();
 244 }
 245
 246 void NORETURN *DieOnFailure::OnOOM() {
 247   atomic_store_relaxed(&allocator_out_of_memory, 1);
 248   ReportAllocatorCannotReturnNull();
 249 }
 250
 251 } // namespace __sanitizer