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1 // Copyright 2014 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 <dlfcn.h> | |
6 #include <errno.h> | |
7 #include <fcntl.h> | |
8 #include <stdbool.h> | |
9 #include <stddef.h> | |
10 #include <stdint.h> | |
11 #include <stdlib.h> | |
12 #include <string.h> | |
13 #include <sys/mman.h> | |
14 #include <unistd.h> | |
15 #include <unwind.h> | |
16 | |
17 #include "tools/android/heap_profiler/heap_profiler.h" | |
18 | |
19 #define HEAP_PROFILER_EXPORT __attribute__((visibility("default"))) | |
20 | |
21 | |
22 static inline __attribute__((always_inline)) | |
23 uint32_t get_backtrace(uintptr_t* frames, uint32_t max_depth); | |
24 | |
25 // Function pointers typedefs for the hooked symbols. | |
26 typedef void* (*mmap_t)(void*, size_t, int, int, int, off_t); | |
27 typedef void* (*mmap2_t)(void*, size_t, int, int, int, off_t); | |
28 typedef void* (*mmap64_t)(void*, size_t, int, int, int, off64_t); | |
29 typedef void* (*mremap_t)(void*, size_t, size_t, unsigned long); | |
30 typedef int (*munmap_t)(void*, size_t); | |
31 typedef void* (*malloc_t)(size_t); | |
32 typedef void* (*calloc_t)(size_t, size_t); | |
33 typedef void* (*realloc_t)(void*, size_t); | |
34 typedef void (*free_t)(void*); | |
35 | |
36 // And their actual definitions. | |
37 static mmap_t real_mmap; | |
38 static mmap2_t real_mmap2; | |
39 static mmap64_t real_mmap64; | |
40 static mremap_t real_mremap; | |
41 static munmap_t real_munmap; | |
42 static malloc_t real_malloc; | |
43 static calloc_t real_calloc; | |
44 static realloc_t real_realloc; | |
45 static free_t real_free; | |
46 static int* has_forked_off_zygote; | |
47 | |
48 HEAP_PROFILER_EXPORT const HeapStats* heap_profiler_stats_for_tests; | |
49 | |
50 // +---------------------------------------------------------------------------+ | |
51 // + Initialization of heap_profiler and lookup of hooks' addresses + | |
52 // +---------------------------------------------------------------------------+ | |
53 __attribute__((constructor)) | |
54 static void initialize() { | |
55 real_mmap = (mmap_t) dlsym(RTLD_NEXT, "mmap"); | |
56 real_mmap2 = (mmap_t) dlsym(RTLD_NEXT, "mmap2"); | |
57 real_mmap64 = (mmap64_t) dlsym(RTLD_NEXT, "mmap64"); | |
58 real_mremap = (mremap_t) dlsym(RTLD_NEXT, "mremap"); | |
59 real_munmap = (munmap_t) dlsym(RTLD_NEXT, "munmap"); | |
60 real_malloc = (malloc_t) dlsym(RTLD_NEXT, "malloc"); | |
61 real_calloc = (calloc_t) dlsym(RTLD_NEXT, "calloc"); | |
62 real_realloc = (realloc_t) dlsym(RTLD_NEXT, "realloc"); | |
63 real_free = (free_t) dlsym(RTLD_NEXT, "free"); | |
64 | |
65 // gMallocLeakZygoteChild is an extra useful piece of information to have. | |
66 // When available, it tells whether we're in the zygote (=0) or forked (=1) | |
67 // a child off it. In the worst case it will be NULL and we'll just ignore it. | |
68 has_forked_off_zygote = (int*) dlsym(RTLD_NEXT, "gMallocLeakZygoteChild"); | |
69 | |
70 // Allocate room for the HeapStats area and initialize the heap profiler. | |
71 // Make an explicit map of /dev/zero (instead of MAP_ANONYMOUS), so that the | |
72 // heap_dump tool can easily spot the mapping in the target process. | |
73 int fd = open("/dev/zero", O_RDONLY); | |
74 if (fd < 0) { | |
75 abort(); // This world has gone wrong. Good night Vienna. | |
76 } | |
77 | |
78 HeapStats* stats = (HeapStats*) real_mmap( | |
79 0, sizeof(HeapStats), PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); | |
80 heap_profiler_stats_for_tests = stats; | |
81 heap_profiler_init(stats); | |
82 } | |
83 | |
84 static inline __attribute__((always_inline)) void unwind_and_record_alloc( | |
85 void* start, size_t size, uint32_t flags) { | |
86 const int errno_save = errno; | |
87 uintptr_t frames[HEAP_PROFILER_MAX_DEPTH]; | |
88 const uint32_t depth = get_backtrace(frames, HEAP_PROFILER_MAX_DEPTH); | |
89 if (has_forked_off_zygote != NULL && *has_forked_off_zygote == 0) | |
90 flags |= HEAP_PROFILER_FLAGS_IN_ZYGOTE; | |
91 heap_profiler_alloc(start, size, frames, depth, flags); | |
92 errno = errno_save; | |
93 } | |
94 | |
95 static inline __attribute__((always_inline)) void discard_alloc( | |
96 void* start, size_t size, uint32_t* old_flags) { | |
97 const int errno_save = errno; | |
98 heap_profiler_free(start, size, old_flags); | |
99 errno = errno_save; | |
100 } | |
101 | |
102 // Flags are non-functional extra decorators that are made available to the | |
103 // final heap_dump tool, to get more details about the source of the allocation. | |
104 static uint32_t get_flags_for_mmap(int fd) { | |
105 return HEAP_PROFILER_FLAGS_MMAP | (fd ? HEAP_PROFILER_FLAGS_MMAP_FILE : 0); | |
106 } | |
107 | |
108 // +---------------------------------------------------------------------------+ | |
109 // + Actual mmap/malloc hooks + | |
110 // +---------------------------------------------------------------------------+ | |
111 HEAP_PROFILER_EXPORT void* mmap( | |
112 void* addr, size_t size, int prot, int flags, int fd, off_t offset) { | |
113 void* ret = real_mmap(addr, size, prot, flags, fd, offset); | |
114 if (ret != MAP_FAILED) | |
115 unwind_and_record_alloc(ret, size, get_flags_for_mmap(fd)); | |
116 return ret; | |
117 } | |
118 | |
119 HEAP_PROFILER_EXPORT void* mmap2( | |
120 void* addr, size_t size, int prot, int flags, int fd, off_t pgoffset) { | |
121 void* ret = real_mmap2(addr, size, prot, flags, fd, pgoffset); | |
122 if (ret != MAP_FAILED) | |
123 unwind_and_record_alloc(ret, size, get_flags_for_mmap(fd)); | |
124 return ret; | |
125 } | |
126 | |
127 HEAP_PROFILER_EXPORT void* mmap64( | |
128 void* addr, size_t size, int prot, int flags, int fd, off64_t offset) { | |
129 void* ret = real_mmap64(addr, size, prot, flags, fd, offset); | |
130 if (ret != MAP_FAILED) | |
131 unwind_and_record_alloc(ret, size, get_flags_for_mmap(fd)); | |
132 return ret; | |
133 } | |
134 | |
135 HEAP_PROFILER_EXPORT void* mremap( | |
136 void* addr, size_t oldlen, size_t newlen, unsigned long flags) { | |
137 void* ret = real_mremap(addr, oldlen, newlen, flags); | |
138 if (ret != MAP_FAILED) { | |
139 uint32_t flags = 0; | |
140 if (addr) | |
141 discard_alloc(addr, oldlen, &flags); | |
142 if (newlen > 0) | |
143 unwind_and_record_alloc(ret, newlen, flags); | |
144 } | |
145 return ret; | |
146 } | |
147 | |
148 HEAP_PROFILER_EXPORT int munmap(void* ptr, size_t size) { | |
149 int ret = real_munmap(ptr, size); | |
150 discard_alloc(ptr, size, /*old_flags=*/NULL); | |
151 return ret; | |
152 } | |
153 | |
154 HEAP_PROFILER_EXPORT void* malloc(size_t byte_count) { | |
155 void* ret = real_malloc(byte_count); | |
156 if (ret != NULL) | |
157 unwind_and_record_alloc(ret, byte_count, HEAP_PROFILER_FLAGS_MALLOC); | |
158 return ret; | |
159 } | |
160 | |
161 HEAP_PROFILER_EXPORT void* calloc(size_t nmemb, size_t size) { | |
162 void* ret = real_calloc(nmemb, size); | |
163 if (ret != NULL) | |
164 unwind_and_record_alloc(ret, nmemb * size, HEAP_PROFILER_FLAGS_MALLOC); | |
165 return ret; | |
166 } | |
167 | |
168 HEAP_PROFILER_EXPORT void* realloc(void* ptr, size_t size) { | |
169 void* ret = real_realloc(ptr, size); | |
170 uint32_t flags = 0; | |
171 if (ptr) | |
172 discard_alloc(ptr, 0, &flags); | |
173 if (ret != NULL) | |
174 unwind_and_record_alloc(ret, size, flags | HEAP_PROFILER_FLAGS_MALLOC); | |
175 return ret; | |
176 } | |
177 | |
178 HEAP_PROFILER_EXPORT void free(void* ptr) { | |
179 real_free(ptr); | |
180 discard_alloc(ptr, 0, /*old_flags=*/NULL); | |
181 } | |
182 | |
183 // +---------------------------------------------------------------------------+ | |
184 // + Stack unwinder + | |
185 // +---------------------------------------------------------------------------+ | |
186 typedef struct { | |
187 uintptr_t* frames; | |
188 uint32_t frame_count; | |
189 uint32_t max_depth; | |
190 bool have_skipped_self; | |
191 } stack_crawl_state_t; | |
192 | |
193 static _Unwind_Reason_Code unwind_fn(struct _Unwind_Context* ctx, void* arg) { | |
194 stack_crawl_state_t* state = (stack_crawl_state_t*) arg; | |
195 uintptr_t ip = _Unwind_GetIP(ctx); | |
196 | |
197 if (ip != 0 && !state->have_skipped_self) { | |
198 state->have_skipped_self = true; | |
199 return _URC_NO_REASON; | |
200 } | |
201 | |
202 state->frames[state->frame_count++] = ip; | |
203 return (state->frame_count >= state->max_depth) ? | |
204 _URC_END_OF_STACK : _URC_NO_REASON; | |
205 } | |
206 | |
207 static uint32_t get_backtrace(uintptr_t* frames, uint32_t max_depth) { | |
208 stack_crawl_state_t state = {.frames = frames, .max_depth = max_depth}; | |
209 _Unwind_Backtrace(unwind_fn, &state); | |
210 return state.frame_count; | |
211 } | |
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