1//===-- msan_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 a part of MemorySanitizer.
11//
12// MemorySanitizer allocator.
13//===----------------------------------------------------------------------===//
14
15#include "sanitizer_common/sanitizer_allocator.h"
16#include "sanitizer_common/sanitizer_allocator_interface.h"
17#include "msan.h"
18#include "msan_allocator.h"
19#include "msan_origin.h"
20#include "msan_thread.h"
21#include "msan_poisoning.h"
22
23namespace __msan {
24
25struct Metadata {
26  uptr requested_size;
27};
28
29struct MsanMapUnmapCallback {
30  void OnMap(uptr p, uptr size) const {}
31  void OnUnmap(uptr p, uptr size) const {
32    __msan_unpoison((void *)p, size);
33
34    // We are about to unmap a chunk of user memory.
35    // Mark the corresponding shadow memory as not needed.
36    FlushUnneededShadowMemory(MEM_TO_SHADOW(p), size);
37    if (__msan_get_track_origins())
38      FlushUnneededShadowMemory(MEM_TO_ORIGIN(p), size);
39  }
40};
41
42#if defined(__mips64)
43  static const uptr kMaxAllowedMallocSize = 2UL << 30;
44  static const uptr kRegionSizeLog = 20;
45  static const uptr kNumRegions = SANITIZER_MMAP_RANGE_SIZE >> kRegionSizeLog;
46  typedef TwoLevelByteMap<(kNumRegions >> 12), 1 << 12> ByteMap;
47  typedef CompactSizeClassMap SizeClassMap;
48
49  typedef SizeClassAllocator32<0, SANITIZER_MMAP_RANGE_SIZE, sizeof(Metadata),
50                               SizeClassMap, kRegionSizeLog, ByteMap,
51                               MsanMapUnmapCallback> PrimaryAllocator;
52#elif defined(__x86_64__)
53  static const uptr kAllocatorSpace = 0x600000000000ULL;
54  static const uptr kAllocatorSize   = 0x80000000000;  // 8T.
55  static const uptr kMetadataSize  = sizeof(Metadata);
56  static const uptr kMaxAllowedMallocSize = 8UL << 30;
57
58  typedef SizeClassAllocator64<kAllocatorSpace, kAllocatorSize, kMetadataSize,
59                             DefaultSizeClassMap,
60                             MsanMapUnmapCallback> PrimaryAllocator;
61#endif
62typedef SizeClassAllocatorLocalCache<PrimaryAllocator> AllocatorCache;
63typedef LargeMmapAllocator<MsanMapUnmapCallback> SecondaryAllocator;
64typedef CombinedAllocator<PrimaryAllocator, AllocatorCache,
65                          SecondaryAllocator> Allocator;
66
67static Allocator allocator;
68static AllocatorCache fallback_allocator_cache;
69static SpinMutex fallback_mutex;
70
71static int inited = 0;
72
73static inline void Init() {
74  if (inited) return;
75  __msan_init();
76  inited = true;  // this must happen before any threads are created.
77  allocator.Init(common_flags()->allocator_may_return_null);
78}
79
80AllocatorCache *GetAllocatorCache(MsanThreadLocalMallocStorage *ms) {
81  CHECK(ms);
82  CHECK_LE(sizeof(AllocatorCache), sizeof(ms->allocator_cache));
83  return reinterpret_cast<AllocatorCache *>(ms->allocator_cache);
84}
85
86void MsanThreadLocalMallocStorage::CommitBack() {
87  allocator.SwallowCache(GetAllocatorCache(this));
88}
89
90static void *MsanAllocate(StackTrace *stack, uptr size, uptr alignment,
91                          bool zeroise) {
92  Init();
93  if (size > kMaxAllowedMallocSize) {
94    Report("WARNING: MemorySanitizer failed to allocate %p bytes\n",
95           (void *)size);
96    return allocator.ReturnNullOrDie();
97  }
98  MsanThread *t = GetCurrentThread();
99  void *allocated;
100  if (t) {
101    AllocatorCache *cache = GetAllocatorCache(&t->malloc_storage());
102    allocated = allocator.Allocate(cache, size, alignment, false);
103  } else {
104    SpinMutexLock l(&fallback_mutex);
105    AllocatorCache *cache = &fallback_allocator_cache;
106    allocated = allocator.Allocate(cache, size, alignment, false);
107  }
108  Metadata *meta =
109      reinterpret_cast<Metadata *>(allocator.GetMetaData(allocated));
110  meta->requested_size = size;
111  if (zeroise) {
112    __msan_clear_and_unpoison(allocated, size);
113  } else if (flags()->poison_in_malloc) {
114    __msan_poison(allocated, size);
115    if (__msan_get_track_origins()) {
116      stack->tag = StackTrace::TAG_ALLOC;
117      Origin o = Origin::CreateHeapOrigin(stack);
118      __msan_set_origin(allocated, size, o.raw_id());
119    }
120  }
121  MSAN_MALLOC_HOOK(allocated, size);
122  return allocated;
123}
124
125void MsanDeallocate(StackTrace *stack, void *p) {
126  CHECK(p);
127  Init();
128  MSAN_FREE_HOOK(p);
129  Metadata *meta = reinterpret_cast<Metadata *>(allocator.GetMetaData(p));
130  uptr size = meta->requested_size;
131  meta->requested_size = 0;
132  // This memory will not be reused by anyone else, so we are free to keep it
133  // poisoned.
134  if (flags()->poison_in_free) {
135    __msan_poison(p, size);
136    if (__msan_get_track_origins()) {
137      stack->tag = StackTrace::TAG_DEALLOC;
138      Origin o = Origin::CreateHeapOrigin(stack);
139      __msan_set_origin(p, size, o.raw_id());
140    }
141  }
142  MsanThread *t = GetCurrentThread();
143  if (t) {
144    AllocatorCache *cache = GetAllocatorCache(&t->malloc_storage());
145    allocator.Deallocate(cache, p);
146  } else {
147    SpinMutexLock l(&fallback_mutex);
148    AllocatorCache *cache = &fallback_allocator_cache;
149    allocator.Deallocate(cache, p);
150  }
151}
152
153void *MsanCalloc(StackTrace *stack, uptr nmemb, uptr size) {
154  Init();
155  if (CallocShouldReturnNullDueToOverflow(size, nmemb))
156    return allocator.ReturnNullOrDie();
157  return MsanReallocate(stack, 0, nmemb * size, sizeof(u64), true);
158}
159
160void *MsanReallocate(StackTrace *stack, void *old_p, uptr new_size,
161                     uptr alignment, bool zeroise) {
162  if (!old_p)
163    return MsanAllocate(stack, new_size, alignment, zeroise);
164  if (!new_size) {
165    MsanDeallocate(stack, old_p);
166    return 0;
167  }
168  Metadata *meta = reinterpret_cast<Metadata*>(allocator.GetMetaData(old_p));
169  uptr old_size = meta->requested_size;
170  uptr actually_allocated_size = allocator.GetActuallyAllocatedSize(old_p);
171  if (new_size <= actually_allocated_size) {
172    // We are not reallocating here.
173    meta->requested_size = new_size;
174    if (new_size > old_size) {
175      if (zeroise) {
176        __msan_clear_and_unpoison((char *)old_p + old_size,
177                                  new_size - old_size);
178      } else if (flags()->poison_in_malloc) {
179        stack->tag = StackTrace::TAG_ALLOC;
180        PoisonMemory((char *)old_p + old_size, new_size - old_size, stack);
181      }
182    }
183    return old_p;
184  }
185  uptr memcpy_size = Min(new_size, old_size);
186  void *new_p = MsanAllocate(stack, new_size, alignment, zeroise);
187  // Printf("realloc: old_size %zd new_size %zd\n", old_size, new_size);
188  if (new_p) {
189    CopyMemory(new_p, old_p, memcpy_size, stack);
190    MsanDeallocate(stack, old_p);
191  }
192  return new_p;
193}
194
195static uptr AllocationSize(const void *p) {
196  if (p == 0) return 0;
197  const void *beg = allocator.GetBlockBegin(p);
198  if (beg != p) return 0;
199  Metadata *b = (Metadata *)allocator.GetMetaData(p);
200  return b->requested_size;
201}
202
203}  // namespace __msan
204
205using namespace __msan;
206
207uptr __sanitizer_get_current_allocated_bytes() {
208  uptr stats[AllocatorStatCount];
209  allocator.GetStats(stats);
210  return stats[AllocatorStatAllocated];
211}
212
213uptr __sanitizer_get_heap_size() {
214  uptr stats[AllocatorStatCount];
215  allocator.GetStats(stats);
216  return stats[AllocatorStatMapped];
217}
218
219uptr __sanitizer_get_free_bytes() { return 1; }
220
221uptr __sanitizer_get_unmapped_bytes() { return 1; }
222
223uptr __sanitizer_get_estimated_allocated_size(uptr size) { return size; }
224
225int __sanitizer_get_ownership(const void *p) { return AllocationSize(p) != 0; }
226
227uptr __sanitizer_get_allocated_size(const void *p) { return AllocationSize(p); }
228