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 #include "sanitizer_platform.h"
21 
22 namespace __sanitizer {
23 
24 // Default allocator names.
25 const char *PrimaryAllocatorName = "SizeClassAllocator";
26 const char *SecondaryAllocatorName = "LargeMmapAllocator";
27 
28 static ALIGNED(64) char internal_alloc_placeholder[sizeof(InternalAllocator)];
29 static atomic_uint8_t internal_allocator_initialized;
30 static StaticSpinMutex internal_alloc_init_mu;
31 
32 static InternalAllocatorCache internal_allocator_cache;
33 static StaticSpinMutex internal_allocator_cache_mu;
34 
35 InternalAllocator *internal_allocator() {
36   InternalAllocator *internal_allocator_instance =
37       reinterpret_cast<InternalAllocator *>(&internal_alloc_placeholder);
38   if (atomic_load(&internal_allocator_initialized, memory_order_acquire) == 0) {
39     SpinMutexLock l(&internal_alloc_init_mu);
40     if (atomic_load(&internal_allocator_initialized, memory_order_relaxed) ==
41         0) {
42       internal_allocator_instance->Init(kReleaseToOSIntervalNever);
43       atomic_store(&internal_allocator_initialized, 1, memory_order_release);
44     }
45   }
46   return internal_allocator_instance;
47 }
48 
49 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
50                               uptr alignment) {
51   if (alignment == 0) alignment = 8;
52   if (cache == 0) {
53     SpinMutexLock l(&internal_allocator_cache_mu);
54     return internal_allocator()->Allocate(&internal_allocator_cache, size,
55                                           alignment);
56   }
57   return internal_allocator()->Allocate(cache, size, alignment);
58 }
59 
60 static void *RawInternalRealloc(void *ptr, uptr size,
61                                 InternalAllocatorCache *cache) {
62   uptr alignment = 8;
63   if (cache == 0) {
64     SpinMutexLock l(&internal_allocator_cache_mu);
65     return internal_allocator()->Reallocate(&internal_allocator_cache, ptr,
66                                             size, alignment);
67   }
68   return internal_allocator()->Reallocate(cache, ptr, size, alignment);
69 }
70 
71 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
72   if (!cache) {
73     SpinMutexLock l(&internal_allocator_cache_mu);
74     return internal_allocator()->Deallocate(&internal_allocator_cache, ptr);
75   }
76   internal_allocator()->Deallocate(cache, ptr);
77 }
78 
79 static void NORETURN ReportInternalAllocatorOutOfMemory(uptr requested_size) {
80   SetAllocatorOutOfMemory();
81   Report("FATAL: %s: internal allocator is out of memory trying to allocate "
82          "0x%zx bytes\n", SanitizerToolName, requested_size);
83   Die();
84 }
85 
86 void *InternalAlloc(uptr size, InternalAllocatorCache *cache, uptr alignment) {
87   void *p = RawInternalAlloc(size, cache, alignment);
88   if (UNLIKELY(!p))
89     ReportInternalAllocatorOutOfMemory(size);
90   return p;
91 }
92 
93 void *InternalRealloc(void *addr, uptr size, InternalAllocatorCache *cache) {
94   void *p = RawInternalRealloc(addr, size, cache);
95   if (UNLIKELY(!p))
96     ReportInternalAllocatorOutOfMemory(size);
97   return p;
98 }
99 
100 void *InternalReallocArray(void *addr, uptr count, uptr size,
101                            InternalAllocatorCache *cache) {
102   if (UNLIKELY(CheckForCallocOverflow(count, size))) {
103     Report(
104         "FATAL: %s: reallocarray parameters overflow: count * size (%zd * %zd) "
105         "cannot be represented in type size_t\n",
106         SanitizerToolName, count, size);
107     Die();
108   }
109   return InternalRealloc(addr, count * size, cache);
110 }
111 
112 void *InternalCalloc(uptr count, uptr size, InternalAllocatorCache *cache) {
113   if (UNLIKELY(CheckForCallocOverflow(count, size))) {
114     Report("FATAL: %s: calloc parameters overflow: count * size (%zd * %zd) "
115            "cannot be represented in type size_t\n", SanitizerToolName, count,
116            size);
117     Die();
118   }
119   void *p = InternalAlloc(count * size, cache);
120   if (LIKELY(p))
121     internal_memset(p, 0, count * size);
122   return p;
123 }
124 
125 void InternalFree(void *addr, InternalAllocatorCache *cache) {
126   RawInternalFree(addr, cache);
127 }
128 
129 void InternalAllocatorLock() SANITIZER_NO_THREAD_SAFETY_ANALYSIS {
130   internal_allocator_cache_mu.Lock();
131   internal_allocator()->ForceLock();
132 }
133 
134 void InternalAllocatorUnlock() SANITIZER_NO_THREAD_SAFETY_ANALYSIS {
135   internal_allocator()->ForceUnlock();
136   internal_allocator_cache_mu.Unlock();
137 }
138 
139 // LowLevelAllocator
140 constexpr uptr kLowLevelAllocatorDefaultAlignment = 8;
141 static uptr low_level_alloc_min_alignment = kLowLevelAllocatorDefaultAlignment;
142 static LowLevelAllocateCallback low_level_alloc_callback;
143 
144 void *LowLevelAllocator::Allocate(uptr size) {
145   // Align allocation size.
146   size = RoundUpTo(size, low_level_alloc_min_alignment);
147   if (allocated_end_ - allocated_current_ < (sptr)size) {
148     uptr size_to_allocate = RoundUpTo(size, GetPageSizeCached());
149     allocated_current_ =
150         (char*)MmapOrDie(size_to_allocate, __func__);
151     allocated_end_ = allocated_current_ + size_to_allocate;
152     if (low_level_alloc_callback) {
153       low_level_alloc_callback((uptr)allocated_current_,
154                                size_to_allocate);
155     }
156   }
157   CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
158   void *res = allocated_current_;
159   allocated_current_ += size;
160   return res;
161 }
162 
163 void SetLowLevelAllocateMinAlignment(uptr alignment) {
164   CHECK(IsPowerOfTwo(alignment));
165   low_level_alloc_min_alignment = Max(alignment, low_level_alloc_min_alignment);
166 }
167 
168 void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
169   low_level_alloc_callback = callback;
170 }
171 
172 // Allocator's OOM and other errors handling support.
173 
174 static atomic_uint8_t allocator_out_of_memory = {0};
175 static atomic_uint8_t allocator_may_return_null = {0};
176 
177 bool IsAllocatorOutOfMemory() {
178   return atomic_load_relaxed(&allocator_out_of_memory);
179 }
180 
181 void SetAllocatorOutOfMemory() {
182   atomic_store_relaxed(&allocator_out_of_memory, 1);
183 }
184 
185 bool AllocatorMayReturnNull() {
186   return atomic_load(&allocator_may_return_null, memory_order_relaxed);
187 }
188 
189 void SetAllocatorMayReturnNull(bool may_return_null) {
190   atomic_store(&allocator_may_return_null, may_return_null,
191                memory_order_relaxed);
192 }
193 
194 void PrintHintAllocatorCannotReturnNull() {
195   Report("HINT: if you don't care about these errors you may set "
196          "allocator_may_return_null=1\n");
197 }
198 
199 static atomic_uint8_t rss_limit_exceeded;
200 
201 bool IsRssLimitExceeded() {
202   return atomic_load(&rss_limit_exceeded, memory_order_relaxed);
203 }
204 
205 void SetRssLimitExceeded(bool limit_exceeded) {
206   atomic_store(&rss_limit_exceeded, limit_exceeded, memory_order_relaxed);
207 }
208 
209 } // namespace __sanitizer
210