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 SANITIZER_GO || 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
140const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
141
142static 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
149void *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
159void *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
173void *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
185void *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
198void 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
208constexpr uptr kLowLevelAllocatorDefaultAlignment = 8;
209static uptr low_level_alloc_min_alignment = kLowLevelAllocatorDefaultAlignment;
210static LowLevelAllocateCallback low_level_alloc_callback;
211
212void *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
231void SetLowLevelAllocateMinAlignment(uptr alignment) {
232  CHECK(IsPowerOfTwo(alignment));
233  low_level_alloc_min_alignment = Max(alignment, low_level_alloc_min_alignment);
234}
235
236void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
237  low_level_alloc_callback = callback;
238}
239
240// Allocator's OOM and other errors handling support.
241
242static atomic_uint8_t allocator_out_of_memory = {0};
243static atomic_uint8_t allocator_may_return_null = {0};
244
245bool IsAllocatorOutOfMemory() {
246  return atomic_load_relaxed(&allocator_out_of_memory);
247}
248
249void SetAllocatorOutOfMemory() {
250  atomic_store_relaxed(&allocator_out_of_memory, 1);
251}
252
253bool AllocatorMayReturnNull() {
254  return atomic_load(&allocator_may_return_null, memory_order_relaxed);
255}
256
257void SetAllocatorMayReturnNull(bool may_return_null) {
258  atomic_store(&allocator_may_return_null, may_return_null,
259               memory_order_relaxed);
260}
261
262void 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
268