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
21namespace __sanitizer {
22
23// Default allocator names.
24const char *PrimaryAllocatorName = "SizeClassAllocator";
25const char *SecondaryAllocatorName = "LargeMmapAllocator";
26
27// ThreadSanitizer for Go uses libc malloc/free.
28#if defined(SANITIZER_USE_MALLOC)
29# if SANITIZER_LINUX && !SANITIZER_ANDROID
30extern "C" void *__libc_malloc(uptr size);
31#  if !SANITIZER_GO
32extern "C" void *__libc_memalign(uptr alignment, uptr size);
33#  endif
34extern "C" void *__libc_realloc(void *ptr, uptr size);
35extern "C" void __libc_free(void *ptr);
36# else
37#  include <stdlib.h>
38#  define __libc_malloc malloc
39#  if !SANITIZER_GO
40static 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
51static 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
70static void *RawInternalRealloc(void *ptr, uptr size,
71                                InternalAllocatorCache *cache) {
72  (void)cache;
73  return __libc_realloc(ptr, size);
74}
75
76static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
77  (void)cache;
78  __libc_free(ptr);
79}
80
81InternalAllocator *internal_allocator() {
82  return 0;
83}
84
85#else  // SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
86
87static ALIGNED(64) char internal_alloc_placeholder[sizeof(InternalAllocator)];
88static atomic_uint8_t internal_allocator_initialized;
89static StaticSpinMutex internal_alloc_init_mu;
90
91static InternalAllocatorCache internal_allocator_cache;
92static StaticSpinMutex internal_allocator_cache_mu;
93
94InternalAllocator *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
108static 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
119static 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
130static 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
140static void NORETURN ReportInternalAllocatorOutOfMemory(uptr requested_size) {
141  SetAllocatorOutOfMemory();
142  Report("FATAL: %s: internal allocator is out of memory trying to allocate "
143         "0x%zx bytes\n", SanitizerToolName, requested_size);
144  Die();
145}
146
147void *InternalAlloc(uptr size, InternalAllocatorCache *cache, uptr alignment) {
148  void *p = RawInternalAlloc(size, cache, alignment);
149  if (UNLIKELY(!p))
150    ReportInternalAllocatorOutOfMemory(size);
151  return p;
152}
153
154void *InternalRealloc(void *addr, uptr size, InternalAllocatorCache *cache) {
155  void *p = RawInternalRealloc(addr, size, cache);
156  if (UNLIKELY(!p))
157    ReportInternalAllocatorOutOfMemory(size);
158  return p;
159}
160
161void *InternalReallocArray(void *addr, uptr count, uptr size,
162                           InternalAllocatorCache *cache) {
163  if (UNLIKELY(CheckForCallocOverflow(count, size))) {
164    Report(
165        "FATAL: %s: reallocarray parameters overflow: count * size (%zd * %zd) "
166        "cannot be represented in type size_t\n",
167        SanitizerToolName, count, size);
168    Die();
169  }
170  return InternalRealloc(addr, count * size, cache);
171}
172
173void *InternalCalloc(uptr count, uptr size, InternalAllocatorCache *cache) {
174  if (UNLIKELY(CheckForCallocOverflow(count, size))) {
175    Report("FATAL: %s: calloc parameters overflow: count * size (%zd * %zd) "
176           "cannot be represented in type size_t\n", SanitizerToolName, count,
177           size);
178    Die();
179  }
180  void *p = InternalAlloc(count * size, cache);
181  if (LIKELY(p))
182    internal_memset(p, 0, count * size);
183  return p;
184}
185
186void InternalFree(void *addr, InternalAllocatorCache *cache) {
187  RawInternalFree(addr, cache);
188}
189
190// LowLevelAllocator
191constexpr uptr kLowLevelAllocatorDefaultAlignment = 8;
192static uptr low_level_alloc_min_alignment = kLowLevelAllocatorDefaultAlignment;
193static LowLevelAllocateCallback low_level_alloc_callback;
194
195void *LowLevelAllocator::Allocate(uptr size) {
196  // Align allocation size.
197  size = RoundUpTo(size, low_level_alloc_min_alignment);
198  if (allocated_end_ - allocated_current_ < (sptr)size) {
199    uptr size_to_allocate = RoundUpTo(size, GetPageSizeCached());
200    allocated_current_ =
201        (char*)MmapOrDie(size_to_allocate, __func__);
202    allocated_end_ = allocated_current_ + size_to_allocate;
203    if (low_level_alloc_callback) {
204      low_level_alloc_callback((uptr)allocated_current_,
205                               size_to_allocate);
206    }
207  }
208  CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
209  void *res = allocated_current_;
210  allocated_current_ += size;
211  return res;
212}
213
214void SetLowLevelAllocateMinAlignment(uptr alignment) {
215  CHECK(IsPowerOfTwo(alignment));
216  low_level_alloc_min_alignment = Max(alignment, low_level_alloc_min_alignment);
217}
218
219void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
220  low_level_alloc_callback = callback;
221}
222
223// Allocator's OOM and other errors handling support.
224
225static atomic_uint8_t allocator_out_of_memory = {0};
226static atomic_uint8_t allocator_may_return_null = {0};
227
228bool IsAllocatorOutOfMemory() {
229  return atomic_load_relaxed(&allocator_out_of_memory);
230}
231
232void SetAllocatorOutOfMemory() {
233  atomic_store_relaxed(&allocator_out_of_memory, 1);
234}
235
236bool AllocatorMayReturnNull() {
237  return atomic_load(&allocator_may_return_null, memory_order_relaxed);
238}
239
240void SetAllocatorMayReturnNull(bool may_return_null) {
241  atomic_store(&allocator_may_return_null, may_return_null,
242               memory_order_relaxed);
243}
244
245void PrintHintAllocatorCannotReturnNull() {
246  Report("HINT: if you don't care about these errors you may set "
247         "allocator_may_return_null=1\n");
248}
249
250} // namespace __sanitizer
251