1 //===-- sanitizer_allocator.cc --------------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file is shared between AddressSanitizer and ThreadSanitizer
11 // run-time libraries.
12 // This allocator is used inside run-times.
13 //===----------------------------------------------------------------------===//
14
15 #include "sanitizer_allocator.h"
16 #include "sanitizer_allocator_internal.h"
17 #include "sanitizer_common.h"
18
19 namespace __sanitizer {
20
21 // ThreadSanitizer for Go uses libc malloc/free.
22 #if defined(SANITIZER_GO) || defined(SANITIZER_USE_MALLOC)
23 # if SANITIZER_LINUX && !SANITIZER_ANDROID
24 extern "C" void *__libc_malloc(uptr size);
25 extern "C" void *__libc_memalign(uptr alignment, uptr size);
26 extern "C" void *__libc_realloc(void *ptr, uptr size);
27 extern "C" void __libc_free(void *ptr);
28 # else
29 # include <stdlib.h>
30 # define __libc_malloc malloc
31 static void *__libc_memalign(uptr alignment, uptr size) {
32 void *p;
33 uptr error = posix_memalign(&p, alignment, size);
34 if (error) return nullptr;
35 return p;
36 }
37 # define __libc_realloc realloc
38 # define __libc_free free
39 # endif
40
RawInternalAlloc(uptr size,InternalAllocatorCache * cache,uptr alignment)41 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
42 uptr alignment) {
43 (void)cache;
44 if (alignment == 0)
45 return __libc_malloc(size);
46 else
47 return __libc_memalign(alignment, size);
48 }
49
RawInternalRealloc(void * ptr,uptr size,InternalAllocatorCache * cache)50 static void *RawInternalRealloc(void *ptr, uptr size,
51 InternalAllocatorCache *cache) {
52 (void)cache;
53 return __libc_realloc(ptr, size);
54 }
55
RawInternalFree(void * ptr,InternalAllocatorCache * cache)56 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
57 (void)cache;
58 __libc_free(ptr);
59 }
60
internal_allocator()61 InternalAllocator *internal_allocator() {
62 return 0;
63 }
64
65 #else // defined(SANITIZER_GO) || defined(SANITIZER_USE_MALLOC)
66
67 static ALIGNED(64) char internal_alloc_placeholder[sizeof(InternalAllocator)];
68 static atomic_uint8_t internal_allocator_initialized;
69 static StaticSpinMutex internal_alloc_init_mu;
70
71 static InternalAllocatorCache internal_allocator_cache;
72 static StaticSpinMutex internal_allocator_cache_mu;
73
74 InternalAllocator *internal_allocator() {
75 InternalAllocator *internal_allocator_instance =
76 reinterpret_cast<InternalAllocator *>(&internal_alloc_placeholder);
77 if (atomic_load(&internal_allocator_initialized, memory_order_acquire) == 0) {
78 SpinMutexLock l(&internal_alloc_init_mu);
79 if (atomic_load(&internal_allocator_initialized, memory_order_relaxed) ==
80 0) {
81 internal_allocator_instance->Init(/* may_return_null*/ false);
82 atomic_store(&internal_allocator_initialized, 1, memory_order_release);
83 }
84 }
85 return internal_allocator_instance;
86 }
87
88 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
89 uptr alignment) {
90 if (alignment == 0) alignment = 8;
91 if (cache == 0) {
92 SpinMutexLock l(&internal_allocator_cache_mu);
93 return internal_allocator()->Allocate(&internal_allocator_cache, size,
94 alignment, false);
95 }
96 return internal_allocator()->Allocate(cache, size, alignment, false);
97 }
98
99 static void *RawInternalRealloc(void *ptr, uptr size,
100 InternalAllocatorCache *cache) {
101 uptr alignment = 8;
102 if (cache == 0) {
103 SpinMutexLock l(&internal_allocator_cache_mu);
104 return internal_allocator()->Reallocate(&internal_allocator_cache, ptr,
105 size, alignment);
106 }
107 return internal_allocator()->Reallocate(cache, ptr, size, alignment);
108 }
109
110 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
111 if (!cache) {
112 SpinMutexLock l(&internal_allocator_cache_mu);
113 return internal_allocator()->Deallocate(&internal_allocator_cache, ptr);
114 }
115 internal_allocator()->Deallocate(cache, ptr);
116 }
117
118 #endif // defined(SANITIZER_GO) || defined(SANITIZER_USE_MALLOC)
119
120 const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
121
InternalAlloc(uptr size,InternalAllocatorCache * cache,uptr alignment)122 void *InternalAlloc(uptr size, InternalAllocatorCache *cache, uptr alignment) {
123 if (size + sizeof(u64) < size)
124 return nullptr;
125 void *p = RawInternalAlloc(size + sizeof(u64), cache, alignment);
126 if (!p)
127 return nullptr;
128 ((u64*)p)[0] = kBlockMagic;
129 return (char*)p + sizeof(u64);
130 }
131
InternalRealloc(void * addr,uptr size,InternalAllocatorCache * cache)132 void *InternalRealloc(void *addr, uptr size, InternalAllocatorCache *cache) {
133 if (!addr)
134 return InternalAlloc(size, cache);
135 if (size + sizeof(u64) < size)
136 return nullptr;
137 addr = (char*)addr - sizeof(u64);
138 size = size + sizeof(u64);
139 CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
140 void *p = RawInternalRealloc(addr, size, cache);
141 if (!p)
142 return nullptr;
143 return (char*)p + sizeof(u64);
144 }
145
InternalCalloc(uptr count,uptr size,InternalAllocatorCache * cache)146 void *InternalCalloc(uptr count, uptr size, InternalAllocatorCache *cache) {
147 if (CallocShouldReturnNullDueToOverflow(count, size))
148 return internal_allocator()->ReturnNullOrDie();
149 void *p = InternalAlloc(count * size, cache);
150 if (p) internal_memset(p, 0, count * size);
151 return p;
152 }
153
InternalFree(void * addr,InternalAllocatorCache * cache)154 void InternalFree(void *addr, InternalAllocatorCache *cache) {
155 if (!addr)
156 return;
157 addr = (char*)addr - sizeof(u64);
158 CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
159 ((u64*)addr)[0] = 0;
160 RawInternalFree(addr, cache);
161 }
162
163 // LowLevelAllocator
164 static LowLevelAllocateCallback low_level_alloc_callback;
165
Allocate(uptr size)166 void *LowLevelAllocator::Allocate(uptr size) {
167 // Align allocation size.
168 size = RoundUpTo(size, 8);
169 if (allocated_end_ - allocated_current_ < (sptr)size) {
170 uptr size_to_allocate = Max(size, GetPageSizeCached());
171 allocated_current_ =
172 (char*)MmapOrDie(size_to_allocate, __func__);
173 allocated_end_ = allocated_current_ + size_to_allocate;
174 if (low_level_alloc_callback) {
175 low_level_alloc_callback((uptr)allocated_current_,
176 size_to_allocate);
177 }
178 }
179 CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
180 void *res = allocated_current_;
181 allocated_current_ += size;
182 return res;
183 }
184
SetLowLevelAllocateCallback(LowLevelAllocateCallback callback)185 void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
186 low_level_alloc_callback = callback;
187 }
188
CallocShouldReturnNullDueToOverflow(uptr size,uptr n)189 bool CallocShouldReturnNullDueToOverflow(uptr size, uptr n) {
190 if (!size) return false;
191 uptr max = (uptr)-1L;
192 return (max / size) < n;
193 }
194
ReportAllocatorCannotReturnNull()195 void NORETURN ReportAllocatorCannotReturnNull() {
196 Report("%s's allocator is terminating the process instead of returning 0\n",
197 SanitizerToolName);
198 Report("If you don't like this behavior set allocator_may_return_null=1\n");
199 CHECK(0);
200 Die();
201 }
202
203 } // namespace __sanitizer
204