libsanitizer/sanitizer_common/sanitizer_allocator.cpp

   1 //===-- sanitizer_allocator.cpp -------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is shared between AddressSanitizer and ThreadSanitizer
  10 // run-time libraries.
  11 // This allocator is used inside run-times.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "sanitizer_allocator.h"
  15
  16 #include "sanitizer_allocator_checks.h"
  17 #include "sanitizer_allocator_internal.h"
  18 #include "sanitizer_atomic.h"
  19 #include "sanitizer_common.h"
  20
  21 namespace __sanitizer {
  22
  23 // Default allocator names.
  24 const char *PrimaryAllocatorName = "SizeClassAllocator";
  25 const char *SecondaryAllocatorName = "LargeMmapAllocator";
  26
  27 // ThreadSanitizer for Go uses libc malloc/free.
  28 #if defined(SANITIZER_USE_MALLOC)
  29 # if SANITIZER_LINUX && !SANITIZER_ANDROID
  30 extern "C" void *__libc_malloc(uptr size);
  31 #  if !SANITIZER_GO
  32 extern "C" void *__libc_memalign(uptr alignment, uptr size);
  33 #  endif
  34 extern "C" void *__libc_realloc(void *ptr, uptr size);
  35 extern "C" void __libc_free(void *ptr);
  36 # else
  37 #  include <stdlib.h>
  38 #  define __libc_malloc malloc
  39 #  if !SANITIZER_GO
  40 static void *__libc_memalign(uptr alignment, uptr size) {
  41   void *p;
  42   uptr error = posix_memalign(&p, alignment, size);
  43   if (error) return nullptr;
  44   return p;
  45 }
  46 #  endif
  47 #  define __libc_realloc realloc
  48 #  define __libc_free free
  49 # endif
  50
  51 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
  52                               uptr alignment) {
  53   (void)cache;
  54 #if !SANITIZER_GO
  55   if (alignment == 0)
  56     return __libc_malloc(size);
  57   else
  58     return __libc_memalign(alignment, size);
  59 #else
  60   // Windows does not provide __libc_memalign/posix_memalign. It provides
  61   // __aligned_malloc, but the allocated blocks can't be passed to free,
  62   // they need to be passed to __aligned_free. InternalAlloc interface does
  63   // not account for such requirement. Alignemnt does not seem to be used
  64   // anywhere in runtime, so just call __libc_malloc for now.
  65   DCHECK_EQ(alignment, 0);
  66   return __libc_malloc(size);
  67 #endif
  68 }
  69
  70 static void *RawInternalRealloc(void *ptr, uptr size,
  71                                 InternalAllocatorCache *cache) {
  72   (void)cache;
  73   return __libc_realloc(ptr, size);
  74 }
  75
  76 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
  77   (void)cache;
  78   __libc_free(ptr);
  79 }
  80
  81 InternalAllocator *internal_allocator() {
  82   return 0;
  83 }
  84
  85 #else  // SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
  86
  87 static ALIGNED(64) char internal_alloc_placeholder[sizeof(InternalAllocator)];
  88 static atomic_uint8_t internal_allocator_initialized;
  89 static StaticSpinMutex internal_alloc_init_mu;
  90
  91 static InternalAllocatorCache internal_allocator_cache;
  92 static StaticSpinMutex internal_allocator_cache_mu;
  93
  94 InternalAllocator *internal_allocator() {
  95   InternalAllocator *internal_allocator_instance =
  96       reinterpret_cast<InternalAllocator *>(&internal_alloc_placeholder);
  97   if (atomic_load(&internal_allocator_initialized, memory_order_acquire) == 0) {
  98     SpinMutexLock l(&internal_alloc_init_mu);
  99     if (atomic_load(&internal_allocator_initialized, memory_order_relaxed) ==
 100         0) {
 101       internal_allocator_instance->Init(kReleaseToOSIntervalNever);
 102       atomic_store(&internal_allocator_initialized, 1, memory_order_release);
 103     }
 104   }
 105   return internal_allocator_instance;
 106 }
 107
 108 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
 109                               uptr alignment) {
 110   if (alignment == 0) alignment = 8;
 111   if (cache == 0) {
 112     SpinMutexLock l(&internal_allocator_cache_mu);
 113     return internal_allocator()->Allocate(&internal_allocator_cache, size,
 114                                           alignment);
 115   }
 116   return internal_allocator()->Allocate(cache, size, alignment);
 117 }
 118
 119 static void *RawInternalRealloc(void *ptr, uptr size,
 120                                 InternalAllocatorCache *cache) {
 121   uptr alignment = 8;
 122   if (cache == 0) {
 123     SpinMutexLock l(&internal_allocator_cache_mu);
 124     return internal_allocator()->Reallocate(&internal_allocator_cache, ptr,
 125                                             size, alignment);
 126   }
 127   return internal_allocator()->Reallocate(cache, ptr, size, alignment);
 128 }
 129
 130 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
 131   if (!cache) {
 132     SpinMutexLock l(&internal_allocator_cache_mu);
 133     return internal_allocator()->Deallocate(&internal_allocator_cache, ptr);
 134   }
 135   internal_allocator()->Deallocate(cache, ptr);
 136 }
 137
 138 #endif  // SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
 139
 140 namespace {
 141 const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
 142
 143 struct BlockHeader {
 144   u64 magic;
 145 };
 146 }  // namespace
 147
 148 static void NORETURN ReportInternalAllocatorOutOfMemory(uptr requested_size) {
 149   SetAllocatorOutOfMemory();
 150   Report("FATAL: %s: internal allocator is out of memory trying to allocate "
 151          "0x%zx bytes\n", SanitizerToolName, requested_size);
 152   Die();
 153 }
 154
 155 void *InternalAlloc(uptr size, InternalAllocatorCache *cache, uptr alignment) {
 156   uptr s = size + sizeof(BlockHeader);
 157   if (s < size)
 158     return nullptr;
 159   BlockHeader *p = (BlockHeader *)RawInternalAlloc(s, cache, alignment);
 160   if (UNLIKELY(!p))
 161     ReportInternalAllocatorOutOfMemory(s);
 162   p->magic = kBlockMagic;
 163   return p + 1;
 164 }
 165
 166 void *InternalRealloc(void *addr, uptr size, InternalAllocatorCache *cache) {
 167   if (!addr)
 168     return InternalAlloc(size, cache);
 169   uptr s = size + sizeof(BlockHeader);
 170   if (s < size)
 171     return nullptr;
 172   BlockHeader *p = (BlockHeader *)addr - 1;
 173   CHECK_EQ(kBlockMagic, p->magic);
 174   p = (BlockHeader *)RawInternalRealloc(p, s, cache);
 175   if (UNLIKELY(!p))
 176     ReportInternalAllocatorOutOfMemory(s);
 177   return p + 1;
 178 }
 179
 180 void *InternalReallocArray(void *addr, uptr count, uptr size,
 181                            InternalAllocatorCache *cache) {
 182   if (UNLIKELY(CheckForCallocOverflow(count, size))) {
 183     Report(
 184         "FATAL: %s: reallocarray parameters overflow: count * size (%zd * %zd) "
 185         "cannot be represented in type size_t\n",
 186         SanitizerToolName, count, size);
 187     Die();
 188   }
 189   return InternalRealloc(addr, count * size, cache);
 190 }
 191
 192 void *InternalCalloc(uptr count, uptr size, InternalAllocatorCache *cache) {
 193   if (UNLIKELY(CheckForCallocOverflow(count, size))) {
 194     Report("FATAL: %s: calloc parameters overflow: count * size (%zd * %zd) "
 195            "cannot be represented in type size_t\n", SanitizerToolName, count,
 196            size);
 197     Die();
 198   }
 199   void *p = InternalAlloc(count * size, cache);
 200   if (LIKELY(p))
 201     internal_memset(p, 0, count * size);
 202   return p;
 203 }
 204
 205 void InternalFree(void *addr, InternalAllocatorCache *cache) {
 206   if (!addr)
 207     return;
 208   BlockHeader *p = (BlockHeader *)addr - 1;
 209   CHECK_EQ(kBlockMagic, p->magic);
 210   p->magic = 0;
 211   RawInternalFree(p, cache);
 212 }
 213
 214 // LowLevelAllocator
 215 constexpr uptr kLowLevelAllocatorDefaultAlignment = 8;
 216 static uptr low_level_alloc_min_alignment = kLowLevelAllocatorDefaultAlignment;
 217 static LowLevelAllocateCallback low_level_alloc_callback;
 218
 219 void *LowLevelAllocator::Allocate(uptr size) {
 220   // Align allocation size.
 221   size = RoundUpTo(size, low_level_alloc_min_alignment);
 222   if (allocated_end_ - allocated_current_ < (sptr)size) {
 223     uptr size_to_allocate = RoundUpTo(size, GetPageSizeCached());
 224     allocated_current_ =
 225         (char*)MmapOrDie(size_to_allocate, __func__);
 226     allocated_end_ = allocated_current_ + size_to_allocate;
 227     if (low_level_alloc_callback) {
 228       low_level_alloc_callback((uptr)allocated_current_,
 229                                size_to_allocate);
 230     }
 231   }
 232   CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
 233   void *res = allocated_current_;
 234   allocated_current_ += size;
 235   return res;
 236 }
 237
 238 void SetLowLevelAllocateMinAlignment(uptr alignment) {
 239   CHECK(IsPowerOfTwo(alignment));
 240   low_level_alloc_min_alignment = Max(alignment, low_level_alloc_min_alignment);
 241 }
 242
 243 void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
 244   low_level_alloc_callback = callback;
 245 }
 246
 247 // Allocator's OOM and other errors handling support.
 248
 249 static atomic_uint8_t allocator_out_of_memory = {0};
 250 static atomic_uint8_t allocator_may_return_null = {0};
 251
 252 bool IsAllocatorOutOfMemory() {
 253   return atomic_load_relaxed(&allocator_out_of_memory);
 254 }
 255
 256 void SetAllocatorOutOfMemory() {
 257   atomic_store_relaxed(&allocator_out_of_memory, 1);
 258 }
 259
 260 bool AllocatorMayReturnNull() {
 261   return atomic_load(&allocator_may_return_null, memory_order_relaxed);
 262 }
 263
 264 void SetAllocatorMayReturnNull(bool may_return_null) {
 265   atomic_store(&allocator_may_return_null, may_return_null,
 266                memory_order_relaxed);
 267 }
 268
 269 void PrintHintAllocatorCannotReturnNull() {
 270   Report("HINT: if you don't care about these errors you may set "
 271          "allocator_may_return_null=1\n");
 272 }
 273
 274 } // namespace __sanitizer