Commit | Line | Data |
---|---|---|
b27f8e75 | 1 | /* |
c0c0989a | 2 | * SPDX-License-Identifier: LGPL-2.1-or-later |
c39c72ee | 3 | * |
c0c0989a MJ |
4 | * Copyright (C) 2009 Pierre-Marc Fournier |
5 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
c39c72ee PMF |
6 | */ |
7 | ||
d7e89462 MD |
8 | /* |
9 | * Do _not_ define _LGPL_SOURCE because we don't want to create a | |
10 | * circular dependency loop between this malloc wrapper, liburcu and | |
11 | * libc. | |
12 | */ | |
ae4b659d | 13 | #include <ust-dlfcn.h> |
e541a28d PMF |
14 | #include <sys/types.h> |
15 | #include <stdio.h> | |
2594a5b4 | 16 | #include <assert.h> |
4c3536e0 MD |
17 | #include <urcu/system.h> |
18 | #include <urcu/uatomic.h> | |
2594a5b4 | 19 | #include <urcu/compiler.h> |
8c06ba6f | 20 | #include <urcu/tls-compat.h> |
20ef5166 | 21 | #include <urcu/arch.h> |
864a1eda | 22 | #include <ust-helper.h> |
cd61d9bf | 23 | #include "ust-compat.h" |
1622ba22 MD |
24 | |
25 | #define TRACEPOINT_DEFINE | |
26 | #define TRACEPOINT_CREATE_PROBES | |
52c95399 | 27 | #define TP_IP_PARAM ip |
1622ba22 | 28 | #include "ust_libc.h" |
fbd8191b | 29 | |
f95b2888 SS |
30 | #define STATIC_CALLOC_LEN 4096 |
31 | static char static_calloc_buf[STATIC_CALLOC_LEN]; | |
4c3536e0 | 32 | static unsigned long static_calloc_buf_offset; |
f95b2888 | 33 | |
2594a5b4 MD |
34 | struct alloc_functions { |
35 | void *(*calloc)(size_t nmemb, size_t size); | |
36 | void *(*malloc)(size_t size); | |
37 | void (*free)(void *ptr); | |
38 | void *(*realloc)(void *ptr, size_t size); | |
39 | void *(*memalign)(size_t alignment, size_t size); | |
40 | int (*posix_memalign)(void **memptr, size_t alignment, size_t size); | |
41 | }; | |
42 | ||
43 | static | |
44 | struct alloc_functions cur_alloc; | |
45 | ||
8c06ba6f MD |
46 | /* |
47 | * Make sure our own use of the LTS compat layer will not cause infinite | |
48 | * recursion by calling calloc. | |
49 | */ | |
50 | ||
51 | static | |
52 | void *static_calloc(size_t nmemb, size_t size); | |
53 | ||
20ef5166 MD |
54 | /* |
55 | * pthread mutex replacement for URCU tls compat layer. | |
56 | */ | |
57 | static int ust_malloc_lock; | |
58 | ||
59 | static __attribute__((unused)) | |
60 | void ust_malloc_spin_lock(pthread_mutex_t *lock) | |
61 | { | |
62 | /* | |
63 | * The memory barrier within cmpxchg takes care of ordering | |
64 | * memory accesses with respect to the start of the critical | |
65 | * section. | |
66 | */ | |
67 | while (uatomic_cmpxchg(&ust_malloc_lock, 0, 1) != 0) | |
68 | caa_cpu_relax(); | |
69 | } | |
70 | ||
71 | static __attribute__((unused)) | |
72 | void ust_malloc_spin_unlock(pthread_mutex_t *lock) | |
73 | { | |
74 | /* | |
75 | * Ensure memory accesses within the critical section do not | |
76 | * leak outside. | |
77 | */ | |
78 | cmm_smp_mb(); | |
79 | uatomic_set(&ust_malloc_lock, 0); | |
80 | } | |
81 | ||
8c06ba6f | 82 | #define calloc static_calloc |
20ef5166 MD |
83 | #define pthread_mutex_lock ust_malloc_spin_lock |
84 | #define pthread_mutex_unlock ust_malloc_spin_unlock | |
16adecf1 | 85 | static DEFINE_URCU_TLS(int, malloc_nesting); |
50170875 CB |
86 | #undef pthread_mutex_unlock |
87 | #undef pthread_mutex_lock | |
8c06ba6f MD |
88 | #undef calloc |
89 | ||
2594a5b4 MD |
90 | /* |
91 | * Static allocator to use when initially executing dlsym(). It keeps a | |
92 | * size_t value of each object size prior to the object. | |
93 | */ | |
94 | static | |
95 | void *static_calloc_aligned(size_t nmemb, size_t size, size_t alignment) | |
f95b2888 | 96 | { |
2594a5b4 MD |
97 | size_t prev_offset, new_offset, res_offset, aligned_offset; |
98 | ||
99 | if (nmemb * size == 0) { | |
100 | return NULL; | |
101 | } | |
f95b2888 | 102 | |
4c3536e0 MD |
103 | /* |
104 | * Protect static_calloc_buf_offset from concurrent updates | |
105 | * using a cmpxchg loop rather than a mutex to remove a | |
106 | * dependency on pthread. This will minimize the risk of bad | |
107 | * interaction between mutex and malloc instrumentation. | |
108 | */ | |
109 | res_offset = CMM_LOAD_SHARED(static_calloc_buf_offset); | |
110 | do { | |
111 | prev_offset = res_offset; | |
b72687b8 | 112 | aligned_offset = LTTNG_UST_ALIGN(prev_offset + sizeof(size_t), alignment); |
2594a5b4 MD |
113 | new_offset = aligned_offset + nmemb * size; |
114 | if (new_offset > sizeof(static_calloc_buf)) { | |
115 | abort(); | |
4c3536e0 | 116 | } |
4c3536e0 MD |
117 | } while ((res_offset = uatomic_cmpxchg(&static_calloc_buf_offset, |
118 | prev_offset, new_offset)) != prev_offset); | |
2594a5b4 MD |
119 | *(size_t *) &static_calloc_buf[aligned_offset - sizeof(size_t)] = size; |
120 | return &static_calloc_buf[aligned_offset]; | |
121 | } | |
122 | ||
123 | static | |
124 | void *static_calloc(size_t nmemb, size_t size) | |
125 | { | |
126 | void *retval; | |
127 | ||
128 | retval = static_calloc_aligned(nmemb, size, 1); | |
2594a5b4 MD |
129 | return retval; |
130 | } | |
131 | ||
132 | static | |
133 | void *static_malloc(size_t size) | |
134 | { | |
135 | void *retval; | |
136 | ||
137 | retval = static_calloc_aligned(1, size, 1); | |
2594a5b4 MD |
138 | return retval; |
139 | } | |
140 | ||
141 | static | |
142 | void static_free(void *ptr) | |
143 | { | |
144 | /* no-op. */ | |
2594a5b4 MD |
145 | } |
146 | ||
147 | static | |
148 | void *static_realloc(void *ptr, size_t size) | |
149 | { | |
150 | size_t *old_size = NULL; | |
151 | void *retval; | |
152 | ||
153 | if (size == 0) { | |
154 | retval = NULL; | |
155 | goto end; | |
156 | } | |
157 | ||
158 | if (ptr) { | |
159 | old_size = (size_t *) ptr - 1; | |
160 | if (size <= *old_size) { | |
161 | /* We can re-use the old entry. */ | |
162 | *old_size = size; | |
163 | retval = ptr; | |
164 | goto end; | |
165 | } | |
166 | } | |
167 | /* We need to expand. Don't free previous memory location. */ | |
168 | retval = static_calloc_aligned(1, size, 1); | |
169 | assert(retval); | |
170 | if (ptr) | |
171 | memcpy(retval, ptr, *old_size); | |
172 | end: | |
2594a5b4 MD |
173 | return retval; |
174 | } | |
175 | ||
176 | static | |
177 | void *static_memalign(size_t alignment, size_t size) | |
178 | { | |
179 | void *retval; | |
180 | ||
181 | retval = static_calloc_aligned(1, size, alignment); | |
2594a5b4 MD |
182 | return retval; |
183 | } | |
184 | ||
185 | static | |
186 | int static_posix_memalign(void **memptr, size_t alignment, size_t size) | |
187 | { | |
2594a5b4 MD |
188 | void *ptr; |
189 | ||
190 | /* Check for power of 2, larger than void *. */ | |
191 | if (alignment & (alignment - 1) | |
192 | || alignment < sizeof(void *) | |
193 | || alignment == 0) { | |
2594a5b4 MD |
194 | goto end; |
195 | } | |
196 | ptr = static_calloc_aligned(1, size, alignment); | |
197 | *memptr = ptr; | |
2594a5b4 | 198 | end: |
2594a5b4 MD |
199 | return 0; |
200 | } | |
201 | ||
202 | static | |
203 | void setup_static_allocator(void) | |
204 | { | |
205 | assert(cur_alloc.calloc == NULL); | |
206 | cur_alloc.calloc = static_calloc; | |
207 | assert(cur_alloc.malloc == NULL); | |
208 | cur_alloc.malloc = static_malloc; | |
209 | assert(cur_alloc.free == NULL); | |
210 | cur_alloc.free = static_free; | |
211 | assert(cur_alloc.realloc == NULL); | |
212 | cur_alloc.realloc = static_realloc; | |
213 | assert(cur_alloc.memalign == NULL); | |
214 | cur_alloc.memalign = static_memalign; | |
215 | assert(cur_alloc.posix_memalign == NULL); | |
216 | cur_alloc.posix_memalign = static_posix_memalign; | |
217 | } | |
218 | ||
219 | static | |
220 | void lookup_all_symbols(void) | |
221 | { | |
222 | struct alloc_functions af; | |
223 | ||
224 | /* | |
225 | * Temporarily redirect allocation functions to | |
226 | * static_calloc_aligned, and free function to static_free | |
227 | * (no-op), until the dlsym lookup has completed. | |
228 | */ | |
229 | setup_static_allocator(); | |
230 | ||
231 | /* Perform the actual lookups */ | |
232 | af.calloc = dlsym(RTLD_NEXT, "calloc"); | |
233 | af.malloc = dlsym(RTLD_NEXT, "malloc"); | |
234 | af.free = dlsym(RTLD_NEXT, "free"); | |
235 | af.realloc = dlsym(RTLD_NEXT, "realloc"); | |
236 | af.memalign = dlsym(RTLD_NEXT, "memalign"); | |
237 | af.posix_memalign = dlsym(RTLD_NEXT, "posix_memalign"); | |
238 | ||
239 | /* Populate the new allocator functions */ | |
240 | memcpy(&cur_alloc, &af, sizeof(cur_alloc)); | |
f95b2888 SS |
241 | } |
242 | ||
e541a28d PMF |
243 | void *malloc(size_t size) |
244 | { | |
1c184644 PMF |
245 | void *retval; |
246 | ||
8c06ba6f | 247 | URCU_TLS(malloc_nesting)++; |
2594a5b4 MD |
248 | if (cur_alloc.malloc == NULL) { |
249 | lookup_all_symbols(); | |
250 | if (cur_alloc.malloc == NULL) { | |
e541a28d | 251 | fprintf(stderr, "mallocwrap: unable to find malloc\n"); |
2594a5b4 | 252 | abort(); |
e541a28d PMF |
253 | } |
254 | } | |
2594a5b4 | 255 | retval = cur_alloc.malloc(size); |
8c06ba6f | 256 | if (URCU_TLS(malloc_nesting) == 1) { |
6d4658aa | 257 | tracepoint(lttng_ust_libc, malloc, |
171fcc6f | 258 | size, retval, LTTNG_UST_CALLER_IP()); |
8c06ba6f MD |
259 | } |
260 | URCU_TLS(malloc_nesting)--; | |
1c184644 PMF |
261 | return retval; |
262 | } | |
263 | ||
264 | void free(void *ptr) | |
265 | { | |
8c06ba6f | 266 | URCU_TLS(malloc_nesting)++; |
2594a5b4 MD |
267 | /* |
268 | * Check whether the memory was allocated with | |
269 | * static_calloc_align, in which case there is nothing to free. | |
f95b2888 | 270 | */ |
2594a5b4 MD |
271 | if (caa_unlikely((char *)ptr >= static_calloc_buf && |
272 | (char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN)) { | |
8c06ba6f MD |
273 | goto end; |
274 | } | |
275 | ||
276 | if (URCU_TLS(malloc_nesting) == 1) { | |
6d4658aa | 277 | tracepoint(lttng_ust_libc, free, |
171fcc6f | 278 | ptr, LTTNG_UST_CALLER_IP()); |
f95b2888 | 279 | } |
1c184644 | 280 | |
2594a5b4 MD |
281 | if (cur_alloc.free == NULL) { |
282 | lookup_all_symbols(); | |
283 | if (cur_alloc.free == NULL) { | |
1c184644 | 284 | fprintf(stderr, "mallocwrap: unable to find free\n"); |
2594a5b4 | 285 | abort(); |
1c184644 PMF |
286 | } |
287 | } | |
2594a5b4 | 288 | cur_alloc.free(ptr); |
8c06ba6f MD |
289 | end: |
290 | URCU_TLS(malloc_nesting)--; | |
e541a28d | 291 | } |
f95b2888 SS |
292 | |
293 | void *calloc(size_t nmemb, size_t size) | |
294 | { | |
f95b2888 SS |
295 | void *retval; |
296 | ||
8c06ba6f | 297 | URCU_TLS(malloc_nesting)++; |
2594a5b4 MD |
298 | if (cur_alloc.calloc == NULL) { |
299 | lookup_all_symbols(); | |
300 | if (cur_alloc.calloc == NULL) { | |
f95b2888 | 301 | fprintf(stderr, "callocwrap: unable to find calloc\n"); |
2594a5b4 | 302 | abort(); |
f95b2888 SS |
303 | } |
304 | } | |
2594a5b4 | 305 | retval = cur_alloc.calloc(nmemb, size); |
8c06ba6f | 306 | if (URCU_TLS(malloc_nesting) == 1) { |
6d4658aa | 307 | tracepoint(lttng_ust_libc, calloc, |
171fcc6f | 308 | nmemb, size, retval, LTTNG_UST_CALLER_IP()); |
8c06ba6f MD |
309 | } |
310 | URCU_TLS(malloc_nesting)--; | |
f95b2888 SS |
311 | return retval; |
312 | } | |
313 | ||
314 | void *realloc(void *ptr, size_t size) | |
315 | { | |
f95b2888 SS |
316 | void *retval; |
317 | ||
8c06ba6f MD |
318 | URCU_TLS(malloc_nesting)++; |
319 | /* | |
320 | * Check whether the memory was allocated with | |
2594a5b4 MD |
321 | * static_calloc_align, in which case there is nothing |
322 | * to free, and we need to copy the old data. | |
323 | */ | |
324 | if (caa_unlikely((char *)ptr >= static_calloc_buf && | |
325 | (char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN)) { | |
326 | size_t *old_size; | |
327 | ||
328 | old_size = (size_t *) ptr - 1; | |
329 | if (cur_alloc.calloc == NULL) { | |
330 | lookup_all_symbols(); | |
331 | if (cur_alloc.calloc == NULL) { | |
332 | fprintf(stderr, "reallocwrap: unable to find calloc\n"); | |
333 | abort(); | |
334 | } | |
335 | } | |
336 | retval = cur_alloc.calloc(1, size); | |
337 | if (retval) { | |
338 | memcpy(retval, ptr, *old_size); | |
339 | } | |
8c06ba6f MD |
340 | /* |
341 | * Mimick that a NULL pointer has been received, so | |
342 | * memory allocation analysis based on the trace don't | |
343 | * get confused by the address from the static | |
344 | * allocator. | |
345 | */ | |
346 | ptr = NULL; | |
2594a5b4 MD |
347 | goto end; |
348 | } | |
349 | ||
350 | if (cur_alloc.realloc == NULL) { | |
351 | lookup_all_symbols(); | |
352 | if (cur_alloc.realloc == NULL) { | |
f95b2888 | 353 | fprintf(stderr, "reallocwrap: unable to find realloc\n"); |
2594a5b4 | 354 | abort(); |
f95b2888 SS |
355 | } |
356 | } | |
2594a5b4 MD |
357 | retval = cur_alloc.realloc(ptr, size); |
358 | end: | |
8c06ba6f | 359 | if (URCU_TLS(malloc_nesting) == 1) { |
6d4658aa | 360 | tracepoint(lttng_ust_libc, realloc, |
171fcc6f | 361 | ptr, size, retval, LTTNG_UST_CALLER_IP()); |
8c06ba6f MD |
362 | } |
363 | URCU_TLS(malloc_nesting)--; | |
f95b2888 SS |
364 | return retval; |
365 | } | |
9d34b226 SS |
366 | |
367 | void *memalign(size_t alignment, size_t size) | |
368 | { | |
9d34b226 SS |
369 | void *retval; |
370 | ||
8c06ba6f | 371 | URCU_TLS(malloc_nesting)++; |
2594a5b4 MD |
372 | if (cur_alloc.memalign == NULL) { |
373 | lookup_all_symbols(); | |
374 | if (cur_alloc.memalign == NULL) { | |
9d34b226 | 375 | fprintf(stderr, "memalignwrap: unable to find memalign\n"); |
2594a5b4 | 376 | abort(); |
9d34b226 SS |
377 | } |
378 | } | |
2594a5b4 | 379 | retval = cur_alloc.memalign(alignment, size); |
8c06ba6f | 380 | if (URCU_TLS(malloc_nesting) == 1) { |
6d4658aa AB |
381 | tracepoint(lttng_ust_libc, memalign, |
382 | alignment, size, retval, | |
171fcc6f | 383 | LTTNG_UST_CALLER_IP()); |
8c06ba6f MD |
384 | } |
385 | URCU_TLS(malloc_nesting)--; | |
9d34b226 SS |
386 | return retval; |
387 | } | |
388 | ||
389 | int posix_memalign(void **memptr, size_t alignment, size_t size) | |
390 | { | |
9d34b226 SS |
391 | int retval; |
392 | ||
8c06ba6f | 393 | URCU_TLS(malloc_nesting)++; |
2594a5b4 MD |
394 | if (cur_alloc.posix_memalign == NULL) { |
395 | lookup_all_symbols(); | |
396 | if (cur_alloc.posix_memalign == NULL) { | |
9d34b226 | 397 | fprintf(stderr, "posix_memalignwrap: unable to find posix_memalign\n"); |
2594a5b4 | 398 | abort(); |
9d34b226 SS |
399 | } |
400 | } | |
2594a5b4 | 401 | retval = cur_alloc.posix_memalign(memptr, alignment, size); |
8c06ba6f | 402 | if (URCU_TLS(malloc_nesting) == 1) { |
6d4658aa AB |
403 | tracepoint(lttng_ust_libc, posix_memalign, |
404 | *memptr, alignment, size, | |
171fcc6f | 405 | retval, LTTNG_UST_CALLER_IP()); |
8c06ba6f MD |
406 | } |
407 | URCU_TLS(malloc_nesting)--; | |
9d34b226 SS |
408 | return retval; |
409 | } | |
2594a5b4 | 410 | |
f4a90c3e MD |
411 | static |
412 | void lttng_ust_fixup_malloc_nesting_tls(void) | |
413 | { | |
414 | asm volatile ("" : : "m" (URCU_TLS(malloc_nesting))); | |
415 | } | |
416 | ||
2594a5b4 MD |
417 | __attribute__((constructor)) |
418 | void lttng_ust_malloc_wrapper_init(void) | |
419 | { | |
420 | /* Initialization already done */ | |
421 | if (cur_alloc.calloc) { | |
422 | return; | |
423 | } | |
f4a90c3e | 424 | lttng_ust_fixup_malloc_nesting_tls(); |
2594a5b4 MD |
425 | /* |
426 | * Ensure the allocator is in place before the process becomes | |
427 | * multithreaded. | |
428 | */ | |
429 | lookup_all_symbols(); | |
430 | } |