1 // Copyright 2016 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "base/allocator/allocator_shim.h"
6 #include "base/compiler_specific.h"
7
8 #include <dlfcn.h>
9 #include <stdio.h>
10 #include <stdlib.h>
11 #include <malloc_np.h>
12
13 // This translation unit defines a default dispatch for the allocator shim which
14 // routes allocations to libc functions.
15 // The code here is strongly inspired from tcmalloc's override_glibc.h.
16
17 extern "C" {
18 void* __malloc(size_t size);
19 void* __calloc(size_t n, size_t size);
20 void* __realloc(void* address, size_t len);
__memalign(size_t alignment,size_t size)21 void* __memalign(size_t alignment, size_t size) {
22 void *ret;
23 if (__posix_memalign(&ret, alignment, size) != 0) {
24 return nullptr;
25 } else {
26 return ret;
27 }
28 }
29 int __posix_memalign(void **ptr, size_t alignment, size_t size);
30 void __free(void* ptr);
31 } // extern "C"
32
33 namespace {
34
35 using base::allocator::AllocatorDispatch;
36
GlibcMalloc(const AllocatorDispatch *,size_t size,void * context)37 void* GlibcMalloc(const AllocatorDispatch*, size_t size, void* context) {
38 return __malloc(size);
39 }
40
GlibcCalloc(const AllocatorDispatch *,size_t n,size_t size,void * context)41 void* GlibcCalloc(const AllocatorDispatch*,
42 size_t n,
43 size_t size,
44 void* context) {
45 return __calloc(n, size);
46 }
47
GlibcRealloc(const AllocatorDispatch *,void * address,size_t size,void * context)48 void* GlibcRealloc(const AllocatorDispatch*,
49 void* address,
50 size_t size,
51 void* context) {
52 return __realloc(address, size);
53 }
54
GlibcMemalign(const AllocatorDispatch *,size_t alignment,size_t size,void * context)55 void* GlibcMemalign(const AllocatorDispatch*,
56 size_t alignment,
57 size_t size,
58 void* context) {
59 return __memalign(alignment, size);
60 }
61
GlibcFree(const AllocatorDispatch *,void * address,void * context)62 void GlibcFree(const AllocatorDispatch*, void* address, void* context) {
63 __free(address);
64 }
65
66 NO_SANITIZE("cfi-icall")
GlibcGetSizeEstimate(const AllocatorDispatch *,void * address,void * context)67 size_t GlibcGetSizeEstimate(const AllocatorDispatch*,
68 void* address,
69 void* context) {
70 // glibc does not expose an alias to resolve malloc_usable_size. Dynamically
71 // resolve it instead. This should be safe because glibc (and hence dlfcn)
72 // does not use malloc_size internally and so there should not be a risk of
73 // recursion.
74 using MallocUsableSizeFunction = decltype(malloc_usable_size)*;
75 static MallocUsableSizeFunction fn_ptr =
76 reinterpret_cast<MallocUsableSizeFunction>(
77 dlsym(RTLD_NEXT, "malloc_usable_size"));
78
79 return fn_ptr(address);
80 }
81
82 } // namespace
83
84 const AllocatorDispatch AllocatorDispatch::default_dispatch = {
85 &GlibcMalloc, /* alloc_function */
86 &GlibcMalloc, /* alloc_unchecked_function */
87 &GlibcCalloc, /* alloc_zero_initialized_function */
88 &GlibcMemalign, /* alloc_aligned_function */
89 &GlibcRealloc, /* realloc_function */
90 &GlibcFree, /* free_function */
91 &GlibcGetSizeEstimate, /* get_size_estimate_function */
92 nullptr, /* batch_malloc_function */
93 nullptr, /* batch_free_function */
94 nullptr, /* free_definite_size_function */
95 nullptr, /* aligned_malloc_function */
96 nullptr, /* aligned_realloc_function */
97 nullptr, /* aligned_free_function */
98 nullptr, /* next */
99 };
100