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 const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
 141
 142 static void NORETURN ReportInternalAllocatorOutOfMemory(uptr requested_size) {
 143   SetAllocatorOutOfMemory();
 144   Report("FATAL: %s: internal allocator is out of memory trying to allocate "
 145          "0x%zx bytes\n", SanitizerToolName, requested_size);
 146   Die();
 147 }
 148
 149 void *InternalAlloc(uptr size, InternalAllocatorCache *cache, uptr alignment) {
 150   if (size + sizeof(u64) < size)
 151     return nullptr;
 152   void *p = RawInternalAlloc(size + sizeof(u64), cache, alignment);
 153   if (UNLIKELY(!p))
 154     ReportInternalAllocatorOutOfMemory(size + sizeof(u64));
 155   ((u64*)p)[0] = kBlockMagic;
 156   return (char*)p + sizeof(u64);
 157 }
 158
 159 void *InternalRealloc(void *addr, uptr size, InternalAllocatorCache *cache) {
 160   if (!addr)
 161     return InternalAlloc(size, cache);
 162   if (size + sizeof(u64) < size)
 163     return nullptr;
 164   addr = (char*)addr - sizeof(u64);
 165   size = size + sizeof(u64);
 166   CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
 167   void *p = RawInternalRealloc(addr, size, cache);
 168   if (UNLIKELY(!p))
 169     ReportInternalAllocatorOutOfMemory(size);
 170   return (char*)p + sizeof(u64);
 171 }
 172
 173 void *InternalReallocArray(void *addr, uptr count, uptr size,
 174                            InternalAllocatorCache *cache) {
 175   if (UNLIKELY(CheckForCallocOverflow(count, size))) {
 176     Report(
 177         "FATAL: %s: reallocarray parameters overflow: count * size (%zd * %zd) "
 178         "cannot be represented in type size_t\n",
 179         SanitizerToolName, count, size);
 180     Die();
 181   }
 182   return InternalRealloc(addr, count * size, cache);
 183 }
 184
 185 void *InternalCalloc(uptr count, uptr size, InternalAllocatorCache *cache) {
 186   if (UNLIKELY(CheckForCallocOverflow(count, size))) {
 187     Report("FATAL: %s: calloc parameters overflow: count * size (%zd * %zd) "
 188            "cannot be represented in type size_t\n", SanitizerToolName, count,
 189            size);
 190     Die();
 191   }
 192   void *p = InternalAlloc(count * size, cache);
 193   if (LIKELY(p))
 194     internal_memset(p, 0, count * size);
 195   return p;
 196 }
 197
 198 void InternalFree(void *addr, InternalAllocatorCache *cache) {
 199   if (!addr)
 200     return;
 201   addr = (char*)addr - sizeof(u64);
 202   CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
 203   ((u64*)addr)[0] = 0;
 204   RawInternalFree(addr, cache);
 205 }
 206
 207 // LowLevelAllocator
 208 constexpr uptr kLowLevelAllocatorDefaultAlignment = 8;
 209 static uptr low_level_alloc_min_alignment = kLowLevelAllocatorDefaultAlignment;
 210 static LowLevelAllocateCallback low_level_alloc_callback;
 211
 212 void *LowLevelAllocator::Allocate(uptr size) {
 213   // Align allocation size.
 214   size = RoundUpTo(size, low_level_alloc_min_alignment);
 215   if (allocated_end_ - allocated_current_ < (sptr)size) {
 216     uptr size_to_allocate = RoundUpTo(size, GetPageSizeCached());
 217     allocated_current_ =
 218         (char*)MmapOrDie(size_to_allocate, __func__);
 219     allocated_end_ = allocated_current_ + size_to_allocate;
 220     if (low_level_alloc_callback) {
 221       low_level_alloc_callback((uptr)allocated_current_,
 222                                size_to_allocate);
 223     }
 224   }
 225   CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
 226   void *res = allocated_current_;
 227   allocated_current_ += size;
 228   return res;
 229 }
 230
 231 void SetLowLevelAllocateMinAlignment(uptr alignment) {
 232   CHECK(IsPowerOfTwo(alignment));
 233   low_level_alloc_min_alignment = Max(alignment, low_level_alloc_min_alignment);
 234 }
 235
 236 void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
 237   low_level_alloc_callback = callback;
 238 }
 239
 240 // Allocator's OOM and other errors handling support.
 241
 242 static atomic_uint8_t allocator_out_of_memory = {0};
 243 static atomic_uint8_t allocator_may_return_null = {0};
 244
 245 bool IsAllocatorOutOfMemory() {
 246   return atomic_load_relaxed(&allocator_out_of_memory);
 247 }
 248
 249 void SetAllocatorOutOfMemory() {
 250   atomic_store_relaxed(&allocator_out_of_memory, 1);
 251 }
 252
 253 bool AllocatorMayReturnNull() {
 254   return atomic_load(&allocator_may_return_null, memory_order_relaxed);
 255 }
 256
 257 void SetAllocatorMayReturnNull(bool may_return_null) {
 258   atomic_store(&allocator_may_return_null, may_return_null,
 259                memory_order_relaxed);
 260 }
 261
 262 void PrintHintAllocatorCannotReturnNull() {
 263   Report("HINT: if you don't care about these errors you may set "
 264          "allocator_may_return_null=1\n");
 265 }
 266
 267 } // namespace __sanitizer