2 * Copyright (C) 2009 Pierre-Marc Fournier
3 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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.
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.
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
21 #include <lttng/ust-dlfcn.h>
22 #include <sys/types.h>
25 #include <urcu/system.h>
26 #include <urcu/uatomic.h>
27 #include <urcu/compiler.h>
28 #include <urcu/tls-compat.h>
29 #include <urcu/arch.h>
30 #include <lttng/align.h>
32 #define TRACEPOINT_DEFINE
33 #define TRACEPOINT_CREATE_PROBES
36 #define STATIC_CALLOC_LEN 4096
37 static char static_calloc_buf
[STATIC_CALLOC_LEN
];
38 static unsigned long static_calloc_buf_offset
;
40 struct alloc_functions
{
41 void *(*calloc
)(size_t nmemb
, size_t size
);
42 void *(*malloc
)(size_t size
);
43 void (*free
)(void *ptr
);
44 void *(*realloc
)(void *ptr
, size_t size
);
45 void *(*memalign
)(size_t alignment
, size_t size
);
46 int (*posix_memalign
)(void **memptr
, size_t alignment
, size_t size
);
50 struct alloc_functions cur_alloc
;
53 * Make sure our own use of the LTS compat layer will not cause infinite
54 * recursion by calling calloc.
58 void *static_calloc(size_t nmemb
, size_t size
);
61 * pthread mutex replacement for URCU tls compat layer.
63 static int ust_malloc_lock
;
65 static __attribute__((unused
))
66 void ust_malloc_spin_lock(pthread_mutex_t
*lock
)
69 * The memory barrier within cmpxchg takes care of ordering
70 * memory accesses with respect to the start of the critical
73 while (uatomic_cmpxchg(&ust_malloc_lock
, 0, 1) != 0)
77 static __attribute__((unused
))
78 void ust_malloc_spin_unlock(pthread_mutex_t
*lock
)
81 * Ensure memory accesses within the critical section do not
85 uatomic_set(&ust_malloc_lock
, 0);
88 #define calloc static_calloc
89 #define pthread_mutex_lock ust_malloc_spin_lock
90 #define pthread_mutex_unlock ust_malloc_spin_unlock
91 static DEFINE_URCU_TLS(int, malloc_nesting
);
92 #undef ust_malloc_spin_unlock
93 #undef ust_malloc_spin_lock
97 * Static allocator to use when initially executing dlsym(). It keeps a
98 * size_t value of each object size prior to the object.
101 void *static_calloc_aligned(size_t nmemb
, size_t size
, size_t alignment
)
103 size_t prev_offset
, new_offset
, res_offset
, aligned_offset
;
105 if (nmemb
* size
== 0) {
110 * Protect static_calloc_buf_offset from concurrent updates
111 * using a cmpxchg loop rather than a mutex to remove a
112 * dependency on pthread. This will minimize the risk of bad
113 * interaction between mutex and malloc instrumentation.
115 res_offset
= CMM_LOAD_SHARED(static_calloc_buf_offset
);
117 prev_offset
= res_offset
;
118 aligned_offset
= ALIGN(prev_offset
+ sizeof(size_t), alignment
);
119 new_offset
= aligned_offset
+ nmemb
* size
;
120 if (new_offset
> sizeof(static_calloc_buf
)) {
123 } while ((res_offset
= uatomic_cmpxchg(&static_calloc_buf_offset
,
124 prev_offset
, new_offset
)) != prev_offset
);
125 *(size_t *) &static_calloc_buf
[aligned_offset
- sizeof(size_t)] = size
;
126 return &static_calloc_buf
[aligned_offset
];
130 void *static_calloc(size_t nmemb
, size_t size
)
134 retval
= static_calloc_aligned(nmemb
, size
, 1);
139 void *static_malloc(size_t size
)
143 retval
= static_calloc_aligned(1, size
, 1);
148 void static_free(void *ptr
)
154 void *static_realloc(void *ptr
, size_t size
)
156 size_t *old_size
= NULL
;
165 old_size
= (size_t *) ptr
- 1;
166 if (size
<= *old_size
) {
167 /* We can re-use the old entry. */
173 /* We need to expand. Don't free previous memory location. */
174 retval
= static_calloc_aligned(1, size
, 1);
177 memcpy(retval
, ptr
, *old_size
);
183 void *static_memalign(size_t alignment
, size_t size
)
187 retval
= static_calloc_aligned(1, size
, alignment
);
192 int static_posix_memalign(void **memptr
, size_t alignment
, size_t size
)
196 /* Check for power of 2, larger than void *. */
197 if (alignment
& (alignment
- 1)
198 || alignment
< sizeof(void *)
202 ptr
= static_calloc_aligned(1, size
, alignment
);
209 void setup_static_allocator(void)
211 assert(cur_alloc
.calloc
== NULL
);
212 cur_alloc
.calloc
= static_calloc
;
213 assert(cur_alloc
.malloc
== NULL
);
214 cur_alloc
.malloc
= static_malloc
;
215 assert(cur_alloc
.free
== NULL
);
216 cur_alloc
.free
= static_free
;
217 assert(cur_alloc
.realloc
== NULL
);
218 cur_alloc
.realloc
= static_realloc
;
219 assert(cur_alloc
.memalign
== NULL
);
220 cur_alloc
.memalign
= static_memalign
;
221 assert(cur_alloc
.posix_memalign
== NULL
);
222 cur_alloc
.posix_memalign
= static_posix_memalign
;
226 void lookup_all_symbols(void)
228 struct alloc_functions af
;
231 * Temporarily redirect allocation functions to
232 * static_calloc_aligned, and free function to static_free
233 * (no-op), until the dlsym lookup has completed.
235 setup_static_allocator();
237 /* Perform the actual lookups */
238 af
.calloc
= dlsym(RTLD_NEXT
, "calloc");
239 af
.malloc
= dlsym(RTLD_NEXT
, "malloc");
240 af
.free
= dlsym(RTLD_NEXT
, "free");
241 af
.realloc
= dlsym(RTLD_NEXT
, "realloc");
242 af
.memalign
= dlsym(RTLD_NEXT
, "memalign");
243 af
.posix_memalign
= dlsym(RTLD_NEXT
, "posix_memalign");
245 /* Populate the new allocator functions */
246 memcpy(&cur_alloc
, &af
, sizeof(cur_alloc
));
249 void *malloc(size_t size
)
253 URCU_TLS(malloc_nesting
)++;
254 if (cur_alloc
.malloc
== NULL
) {
255 lookup_all_symbols();
256 if (cur_alloc
.malloc
== NULL
) {
257 fprintf(stderr
, "mallocwrap: unable to find malloc\n");
261 retval
= cur_alloc
.malloc(size
);
262 if (URCU_TLS(malloc_nesting
) == 1) {
263 tracepoint(ust_libc
, malloc
, size
, retval
, __builtin_return_address(0));
265 URCU_TLS(malloc_nesting
)--;
271 URCU_TLS(malloc_nesting
)++;
273 * Check whether the memory was allocated with
274 * static_calloc_align, in which case there is nothing to free.
276 if (caa_unlikely((char *)ptr
>= static_calloc_buf
&&
277 (char *)ptr
< static_calloc_buf
+ STATIC_CALLOC_LEN
)) {
281 if (URCU_TLS(malloc_nesting
) == 1) {
282 tracepoint(ust_libc
, free
, ptr
, __builtin_return_address(0));
285 if (cur_alloc
.free
== NULL
) {
286 lookup_all_symbols();
287 if (cur_alloc
.free
== NULL
) {
288 fprintf(stderr
, "mallocwrap: unable to find free\n");
294 URCU_TLS(malloc_nesting
)--;
297 void *calloc(size_t nmemb
, size_t size
)
301 URCU_TLS(malloc_nesting
)++;
302 if (cur_alloc
.calloc
== NULL
) {
303 lookup_all_symbols();
304 if (cur_alloc
.calloc
== NULL
) {
305 fprintf(stderr
, "callocwrap: unable to find calloc\n");
309 retval
= cur_alloc
.calloc(nmemb
, size
);
310 if (URCU_TLS(malloc_nesting
) == 1) {
311 tracepoint(ust_libc
, calloc
, nmemb
, size
, retval
, __builtin_return_address(0));
313 URCU_TLS(malloc_nesting
)--;
317 void *realloc(void *ptr
, size_t size
)
321 URCU_TLS(malloc_nesting
)++;
323 * Check whether the memory was allocated with
324 * static_calloc_align, in which case there is nothing
325 * to free, and we need to copy the old data.
327 if (caa_unlikely((char *)ptr
>= static_calloc_buf
&&
328 (char *)ptr
< static_calloc_buf
+ STATIC_CALLOC_LEN
)) {
331 old_size
= (size_t *) ptr
- 1;
332 if (cur_alloc
.calloc
== NULL
) {
333 lookup_all_symbols();
334 if (cur_alloc
.calloc
== NULL
) {
335 fprintf(stderr
, "reallocwrap: unable to find calloc\n");
339 retval
= cur_alloc
.calloc(1, size
);
341 memcpy(retval
, ptr
, *old_size
);
344 * Mimick that a NULL pointer has been received, so
345 * memory allocation analysis based on the trace don't
346 * get confused by the address from the static
353 if (cur_alloc
.realloc
== NULL
) {
354 lookup_all_symbols();
355 if (cur_alloc
.realloc
== NULL
) {
356 fprintf(stderr
, "reallocwrap: unable to find realloc\n");
360 retval
= cur_alloc
.realloc(ptr
, size
);
362 if (URCU_TLS(malloc_nesting
) == 1) {
363 tracepoint(ust_libc
, realloc
, ptr
, size
, retval
, __builtin_return_address(0));
365 URCU_TLS(malloc_nesting
)--;
369 void *memalign(size_t alignment
, size_t size
)
373 URCU_TLS(malloc_nesting
)++;
374 if (cur_alloc
.memalign
== NULL
) {
375 lookup_all_symbols();
376 if (cur_alloc
.memalign
== NULL
) {
377 fprintf(stderr
, "memalignwrap: unable to find memalign\n");
381 retval
= cur_alloc
.memalign(alignment
, size
);
382 if (URCU_TLS(malloc_nesting
) == 1) {
383 tracepoint(ust_libc
, memalign
, alignment
, size
, retval
, __builtin_return_address(0));
385 URCU_TLS(malloc_nesting
)--;
389 int posix_memalign(void **memptr
, size_t alignment
, size_t size
)
393 URCU_TLS(malloc_nesting
)++;
394 if (cur_alloc
.posix_memalign
== NULL
) {
395 lookup_all_symbols();
396 if (cur_alloc
.posix_memalign
== NULL
) {
397 fprintf(stderr
, "posix_memalignwrap: unable to find posix_memalign\n");
401 retval
= cur_alloc
.posix_memalign(memptr
, alignment
, size
);
402 if (URCU_TLS(malloc_nesting
) == 1) {
403 tracepoint(ust_libc
, posix_memalign
, *memptr
, alignment
, size
,
404 retval
, __builtin_return_address(0));
406 URCU_TLS(malloc_nesting
)--;
410 __attribute__((constructor
))
411 void lttng_ust_malloc_wrapper_init(void)
413 /* Initialization already done */
414 if (cur_alloc
.calloc
) {
418 * Ensure the allocator is in place before the process becomes
421 lookup_all_symbols();