Commit | Line | Data |
---|---|---|
b27f8e75 MD |
1 | /* |
2 | * Copyright (C) 2009 Pierre-Marc Fournier | |
1622ba22 | 3 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
c39c72ee PMF |
4 | * |
5 | * This library is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU Lesser General Public | |
7 | * License as published by the Free Software Foundation; either | |
8 | * version 2.1 of the License, or (at your option) any later version. | |
9 | * | |
10 | * This library is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | * Lesser General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU Lesser General Public | |
16 | * License along with this library; if not, write to the Free Software | |
17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
18 | */ | |
19 | ||
e541a28d | 20 | #define _GNU_SOURCE |
f02baefb | 21 | #include <lttng/ust-dlfcn.h> |
e541a28d PMF |
22 | #include <sys/types.h> |
23 | #include <stdio.h> | |
2594a5b4 | 24 | #include <assert.h> |
4c3536e0 MD |
25 | #include <urcu/system.h> |
26 | #include <urcu/uatomic.h> | |
2594a5b4 MD |
27 | #include <urcu/compiler.h> |
28 | #include <lttng/align.h> | |
1622ba22 MD |
29 | |
30 | #define TRACEPOINT_DEFINE | |
31 | #define TRACEPOINT_CREATE_PROBES | |
32 | #include "ust_libc.h" | |
fbd8191b | 33 | |
f95b2888 SS |
34 | #define STATIC_CALLOC_LEN 4096 |
35 | static char static_calloc_buf[STATIC_CALLOC_LEN]; | |
4c3536e0 | 36 | static unsigned long static_calloc_buf_offset; |
f95b2888 | 37 | |
2594a5b4 MD |
38 | struct alloc_functions { |
39 | void *(*calloc)(size_t nmemb, size_t size); | |
40 | void *(*malloc)(size_t size); | |
41 | void (*free)(void *ptr); | |
42 | void *(*realloc)(void *ptr, size_t size); | |
43 | void *(*memalign)(size_t alignment, size_t size); | |
44 | int (*posix_memalign)(void **memptr, size_t alignment, size_t size); | |
45 | }; | |
46 | ||
47 | static | |
48 | struct alloc_functions cur_alloc; | |
49 | ||
50 | /* | |
51 | * Static allocator to use when initially executing dlsym(). It keeps a | |
52 | * size_t value of each object size prior to the object. | |
53 | */ | |
54 | static | |
55 | void *static_calloc_aligned(size_t nmemb, size_t size, size_t alignment) | |
f95b2888 | 56 | { |
2594a5b4 MD |
57 | size_t prev_offset, new_offset, res_offset, aligned_offset; |
58 | ||
59 | if (nmemb * size == 0) { | |
60 | return NULL; | |
61 | } | |
f95b2888 | 62 | |
4c3536e0 MD |
63 | /* |
64 | * Protect static_calloc_buf_offset from concurrent updates | |
65 | * using a cmpxchg loop rather than a mutex to remove a | |
66 | * dependency on pthread. This will minimize the risk of bad | |
67 | * interaction between mutex and malloc instrumentation. | |
68 | */ | |
69 | res_offset = CMM_LOAD_SHARED(static_calloc_buf_offset); | |
70 | do { | |
71 | prev_offset = res_offset; | |
2594a5b4 MD |
72 | aligned_offset = ALIGN(prev_offset + sizeof(size_t), alignment); |
73 | new_offset = aligned_offset + nmemb * size; | |
74 | if (new_offset > sizeof(static_calloc_buf)) { | |
75 | abort(); | |
4c3536e0 | 76 | } |
4c3536e0 MD |
77 | } while ((res_offset = uatomic_cmpxchg(&static_calloc_buf_offset, |
78 | prev_offset, new_offset)) != prev_offset); | |
2594a5b4 MD |
79 | *(size_t *) &static_calloc_buf[aligned_offset - sizeof(size_t)] = size; |
80 | return &static_calloc_buf[aligned_offset]; | |
81 | } | |
82 | ||
83 | static | |
84 | void *static_calloc(size_t nmemb, size_t size) | |
85 | { | |
86 | void *retval; | |
87 | ||
88 | retval = static_calloc_aligned(nmemb, size, 1); | |
89 | tracepoint(ust_libc, calloc, nmemb, size, retval); | |
90 | return retval; | |
91 | } | |
92 | ||
93 | static | |
94 | void *static_malloc(size_t size) | |
95 | { | |
96 | void *retval; | |
97 | ||
98 | retval = static_calloc_aligned(1, size, 1); | |
99 | tracepoint(ust_libc, malloc, size, retval); | |
100 | return retval; | |
101 | } | |
102 | ||
103 | static | |
104 | void static_free(void *ptr) | |
105 | { | |
106 | /* no-op. */ | |
107 | tracepoint(ust_libc, free, ptr); | |
108 | } | |
109 | ||
110 | static | |
111 | void *static_realloc(void *ptr, size_t size) | |
112 | { | |
113 | size_t *old_size = NULL; | |
114 | void *retval; | |
115 | ||
116 | if (size == 0) { | |
117 | retval = NULL; | |
118 | goto end; | |
119 | } | |
120 | ||
121 | if (ptr) { | |
122 | old_size = (size_t *) ptr - 1; | |
123 | if (size <= *old_size) { | |
124 | /* We can re-use the old entry. */ | |
125 | *old_size = size; | |
126 | retval = ptr; | |
127 | goto end; | |
128 | } | |
129 | } | |
130 | /* We need to expand. Don't free previous memory location. */ | |
131 | retval = static_calloc_aligned(1, size, 1); | |
132 | assert(retval); | |
133 | if (ptr) | |
134 | memcpy(retval, ptr, *old_size); | |
135 | end: | |
136 | tracepoint(ust_libc, realloc, ptr, size, retval); | |
137 | return retval; | |
138 | } | |
139 | ||
140 | static | |
141 | void *static_memalign(size_t alignment, size_t size) | |
142 | { | |
143 | void *retval; | |
144 | ||
145 | retval = static_calloc_aligned(1, size, alignment); | |
146 | tracepoint(ust_libc, memalign, alignment, size, retval); | |
147 | return retval; | |
148 | } | |
149 | ||
150 | static | |
151 | int static_posix_memalign(void **memptr, size_t alignment, size_t size) | |
152 | { | |
153 | int retval = 0; | |
154 | void *ptr; | |
155 | ||
156 | /* Check for power of 2, larger than void *. */ | |
157 | if (alignment & (alignment - 1) | |
158 | || alignment < sizeof(void *) | |
159 | || alignment == 0) { | |
160 | retval = EINVAL; | |
161 | goto end; | |
162 | } | |
163 | ptr = static_calloc_aligned(1, size, alignment); | |
164 | *memptr = ptr; | |
165 | if (size && !ptr) | |
166 | retval = ENOMEM; | |
167 | end: | |
168 | tracepoint(ust_libc, posix_memalign, *memptr, alignment, size, retval); | |
169 | return 0; | |
170 | } | |
171 | ||
172 | static | |
173 | void setup_static_allocator(void) | |
174 | { | |
175 | assert(cur_alloc.calloc == NULL); | |
176 | cur_alloc.calloc = static_calloc; | |
177 | assert(cur_alloc.malloc == NULL); | |
178 | cur_alloc.malloc = static_malloc; | |
179 | assert(cur_alloc.free == NULL); | |
180 | cur_alloc.free = static_free; | |
181 | assert(cur_alloc.realloc == NULL); | |
182 | cur_alloc.realloc = static_realloc; | |
183 | assert(cur_alloc.memalign == NULL); | |
184 | cur_alloc.memalign = static_memalign; | |
185 | assert(cur_alloc.posix_memalign == NULL); | |
186 | cur_alloc.posix_memalign = static_posix_memalign; | |
187 | } | |
188 | ||
189 | static | |
190 | void lookup_all_symbols(void) | |
191 | { | |
192 | struct alloc_functions af; | |
193 | ||
194 | /* | |
195 | * Temporarily redirect allocation functions to | |
196 | * static_calloc_aligned, and free function to static_free | |
197 | * (no-op), until the dlsym lookup has completed. | |
198 | */ | |
199 | setup_static_allocator(); | |
200 | ||
201 | /* Perform the actual lookups */ | |
202 | af.calloc = dlsym(RTLD_NEXT, "calloc"); | |
203 | af.malloc = dlsym(RTLD_NEXT, "malloc"); | |
204 | af.free = dlsym(RTLD_NEXT, "free"); | |
205 | af.realloc = dlsym(RTLD_NEXT, "realloc"); | |
206 | af.memalign = dlsym(RTLD_NEXT, "memalign"); | |
207 | af.posix_memalign = dlsym(RTLD_NEXT, "posix_memalign"); | |
208 | ||
209 | /* Populate the new allocator functions */ | |
210 | memcpy(&cur_alloc, &af, sizeof(cur_alloc)); | |
f95b2888 SS |
211 | } |
212 | ||
e541a28d PMF |
213 | void *malloc(size_t size) |
214 | { | |
1c184644 PMF |
215 | void *retval; |
216 | ||
2594a5b4 MD |
217 | if (cur_alloc.malloc == NULL) { |
218 | lookup_all_symbols(); | |
219 | if (cur_alloc.malloc == NULL) { | |
e541a28d | 220 | fprintf(stderr, "mallocwrap: unable to find malloc\n"); |
2594a5b4 | 221 | abort(); |
e541a28d PMF |
222 | } |
223 | } | |
2594a5b4 | 224 | retval = cur_alloc.malloc(size); |
1622ba22 | 225 | tracepoint(ust_libc, malloc, size, retval); |
1c184644 PMF |
226 | return retval; |
227 | } | |
228 | ||
229 | void free(void *ptr) | |
230 | { | |
2594a5b4 | 231 | tracepoint(ust_libc, free, ptr); |
f95b2888 | 232 | |
2594a5b4 MD |
233 | /* |
234 | * Check whether the memory was allocated with | |
235 | * static_calloc_align, in which case there is nothing to free. | |
f95b2888 | 236 | */ |
2594a5b4 MD |
237 | if (caa_unlikely((char *)ptr >= static_calloc_buf && |
238 | (char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN)) { | |
f95b2888 SS |
239 | return; |
240 | } | |
1c184644 | 241 | |
2594a5b4 MD |
242 | if (cur_alloc.free == NULL) { |
243 | lookup_all_symbols(); | |
244 | if (cur_alloc.free == NULL) { | |
1c184644 | 245 | fprintf(stderr, "mallocwrap: unable to find free\n"); |
2594a5b4 | 246 | abort(); |
1c184644 PMF |
247 | } |
248 | } | |
2594a5b4 | 249 | cur_alloc.free(ptr); |
e541a28d | 250 | } |
f95b2888 SS |
251 | |
252 | void *calloc(size_t nmemb, size_t size) | |
253 | { | |
f95b2888 SS |
254 | void *retval; |
255 | ||
2594a5b4 MD |
256 | if (cur_alloc.calloc == NULL) { |
257 | lookup_all_symbols(); | |
258 | if (cur_alloc.calloc == NULL) { | |
f95b2888 | 259 | fprintf(stderr, "callocwrap: unable to find calloc\n"); |
2594a5b4 | 260 | abort(); |
f95b2888 SS |
261 | } |
262 | } | |
2594a5b4 | 263 | retval = cur_alloc.calloc(nmemb, size); |
f95b2888 SS |
264 | tracepoint(ust_libc, calloc, nmemb, size, retval); |
265 | return retval; | |
266 | } | |
267 | ||
268 | void *realloc(void *ptr, size_t size) | |
269 | { | |
f95b2888 SS |
270 | void *retval; |
271 | ||
2594a5b4 MD |
272 | /* Check whether the memory was allocated with |
273 | * static_calloc_align, in which case there is nothing | |
274 | * to free, and we need to copy the old data. | |
275 | */ | |
276 | if (caa_unlikely((char *)ptr >= static_calloc_buf && | |
277 | (char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN)) { | |
278 | size_t *old_size; | |
279 | ||
280 | old_size = (size_t *) ptr - 1; | |
281 | if (cur_alloc.calloc == NULL) { | |
282 | lookup_all_symbols(); | |
283 | if (cur_alloc.calloc == NULL) { | |
284 | fprintf(stderr, "reallocwrap: unable to find calloc\n"); | |
285 | abort(); | |
286 | } | |
287 | } | |
288 | retval = cur_alloc.calloc(1, size); | |
289 | if (retval) { | |
290 | memcpy(retval, ptr, *old_size); | |
291 | } | |
292 | goto end; | |
293 | } | |
294 | ||
295 | if (cur_alloc.realloc == NULL) { | |
296 | lookup_all_symbols(); | |
297 | if (cur_alloc.realloc == NULL) { | |
f95b2888 | 298 | fprintf(stderr, "reallocwrap: unable to find realloc\n"); |
2594a5b4 | 299 | abort(); |
f95b2888 SS |
300 | } |
301 | } | |
2594a5b4 MD |
302 | retval = cur_alloc.realloc(ptr, size); |
303 | end: | |
f95b2888 SS |
304 | tracepoint(ust_libc, realloc, ptr, size, retval); |
305 | return retval; | |
306 | } | |
9d34b226 SS |
307 | |
308 | void *memalign(size_t alignment, size_t size) | |
309 | { | |
9d34b226 SS |
310 | void *retval; |
311 | ||
2594a5b4 MD |
312 | if (cur_alloc.memalign == NULL) { |
313 | lookup_all_symbols(); | |
314 | if (cur_alloc.memalign == NULL) { | |
9d34b226 | 315 | fprintf(stderr, "memalignwrap: unable to find memalign\n"); |
2594a5b4 | 316 | abort(); |
9d34b226 SS |
317 | } |
318 | } | |
2594a5b4 | 319 | retval = cur_alloc.memalign(alignment, size); |
9d34b226 SS |
320 | tracepoint(ust_libc, memalign, alignment, size, retval); |
321 | return retval; | |
322 | } | |
323 | ||
324 | int posix_memalign(void **memptr, size_t alignment, size_t size) | |
325 | { | |
9d34b226 SS |
326 | int retval; |
327 | ||
2594a5b4 MD |
328 | if (cur_alloc.posix_memalign == NULL) { |
329 | lookup_all_symbols(); | |
330 | if (cur_alloc.posix_memalign == NULL) { | |
9d34b226 | 331 | fprintf(stderr, "posix_memalignwrap: unable to find posix_memalign\n"); |
2594a5b4 | 332 | abort(); |
9d34b226 SS |
333 | } |
334 | } | |
2594a5b4 | 335 | retval = cur_alloc.posix_memalign(memptr, alignment, size); |
9d34b226 SS |
336 | tracepoint(ust_libc, posix_memalign, *memptr, alignment, size, retval); |
337 | return retval; | |
338 | } | |
2594a5b4 MD |
339 | |
340 | __attribute__((constructor)) | |
341 | void lttng_ust_malloc_wrapper_init(void) | |
342 | { | |
343 | /* Initialization already done */ | |
344 | if (cur_alloc.calloc) { | |
345 | return; | |
346 | } | |
347 | /* | |
348 | * Ensure the allocator is in place before the process becomes | |
349 | * multithreaded. | |
350 | */ | |
351 | lookup_all_symbols(); | |
352 | } |