[lttng-ust.git] / liblttng-ust-libc-wrapper / lttng-ust-malloc.c

/*
 * Copyright (C) 2009  Pierre-Marc Fournier
 * Copyright (C) 2011  Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 */

#define _GNU_SOURCE
#include <lttng/ust-dlfcn.h>
#include <sys/types.h>
#include <stdio.h>
#include <assert.h>
#include <urcu/system.h>
#include <urcu/uatomic.h>
#include <urcu/compiler.h>
#include <urcu/tls-compat.h>
#include <urcu/arch.h>
#include <lttng/align.h>
#include <helper.h>

#define TRACEPOINT_DEFINE
#define TRACEPOINT_CREATE_PROBES
#define TP_IP_PARAM ip
#include "ust_libc.h"

#define STATIC_CALLOC_LEN 4096
static char static_calloc_buf[STATIC_CALLOC_LEN];
static unsigned long static_calloc_buf_offset;

struct alloc_functions {
	void *(*calloc)(size_t nmemb, size_t size);
	void *(*malloc)(size_t size);
	void (*free)(void *ptr);
	void *(*realloc)(void *ptr, size_t size);
	void *(*memalign)(size_t alignment, size_t size);
	int (*posix_memalign)(void **memptr, size_t alignment, size_t size);
};

static
struct alloc_functions cur_alloc;

/*
 * Make sure our own use of the LTS compat layer will not cause infinite
 * recursion by calling calloc.
 */

static
void *static_calloc(size_t nmemb, size_t size);

/*
 * pthread mutex replacement for URCU tls compat layer.
 */
static int ust_malloc_lock;

static __attribute__((unused))
void ust_malloc_spin_lock(pthread_mutex_t *lock)
{
	/*
	 * The memory barrier within cmpxchg takes care of ordering
	 * memory accesses with respect to the start of the critical
	 * section.
	 */
	while (uatomic_cmpxchg(&ust_malloc_lock, 0, 1) != 0)
		caa_cpu_relax();
}

static __attribute__((unused))
void ust_malloc_spin_unlock(pthread_mutex_t *lock)
{
	/*
	 * Ensure memory accesses within the critical section do not
	 * leak outside.
	 */
	cmm_smp_mb();
	uatomic_set(&ust_malloc_lock, 0);
}

#define calloc static_calloc
#define pthread_mutex_lock ust_malloc_spin_lock
#define pthread_mutex_unlock ust_malloc_spin_unlock
static DEFINE_URCU_TLS(int, malloc_nesting);
#undef ust_malloc_spin_unlock
#undef ust_malloc_spin_lock
#undef calloc

/*
 * Static allocator to use when initially executing dlsym(). It keeps a
 * size_t value of each object size prior to the object.
 */
static
void *static_calloc_aligned(size_t nmemb, size_t size, size_t alignment)
{
	size_t prev_offset, new_offset, res_offset, aligned_offset;

	if (nmemb * size == 0) {
		return NULL;
	}

	/*
	 * Protect static_calloc_buf_offset from concurrent updates
	 * using a cmpxchg loop rather than a mutex to remove a
	 * dependency on pthread. This will minimize the risk of bad
	 * interaction between mutex and malloc instrumentation.
	 */
	res_offset = CMM_LOAD_SHARED(static_calloc_buf_offset);
	do {
		prev_offset = res_offset;
		aligned_offset = ALIGN(prev_offset + sizeof(size_t), alignment);
		new_offset = aligned_offset + nmemb * size;
		if (new_offset > sizeof(static_calloc_buf)) {
			abort();
		}
	} while ((res_offset = uatomic_cmpxchg(&static_calloc_buf_offset,
			prev_offset, new_offset)) != prev_offset);
	*(size_t *) &static_calloc_buf[aligned_offset - sizeof(size_t)] = size;
	return &static_calloc_buf[aligned_offset];
}

static
void *static_calloc(size_t nmemb, size_t size)
{
	void *retval;

	retval = static_calloc_aligned(nmemb, size, 1);
	return retval;
}

static
void *static_malloc(size_t size)
{
	void *retval;

	retval = static_calloc_aligned(1, size, 1);
	return retval;
}

static
void static_free(void *ptr)
{
	/* no-op. */
}

static
void *static_realloc(void *ptr, size_t size)
{
	size_t *old_size = NULL;
	void *retval;

	if (size == 0) {
		retval = NULL;
		goto end;
	}

	if (ptr) {
		old_size = (size_t *) ptr - 1;
		if (size <= *old_size) {
			/* We can re-use the old entry. */
			*old_size = size;
			retval = ptr;
			goto end;
		}
	}
	/* We need to expand. Don't free previous memory location. */
	retval = static_calloc_aligned(1, size, 1);
	assert(retval);
	if (ptr)
		memcpy(retval, ptr, *old_size);
end:
	return retval;
}

static
void *static_memalign(size_t alignment, size_t size)
{
	void *retval;

	retval = static_calloc_aligned(1, size, alignment);
	return retval;
}

static
int static_posix_memalign(void **memptr, size_t alignment, size_t size)
{
	void *ptr;

	/* Check for power of 2, larger than void *. */
	if (alignment & (alignment - 1)
			|| alignment < sizeof(void *)
			|| alignment == 0) {
		goto end;
	}
	ptr = static_calloc_aligned(1, size, alignment);
	*memptr = ptr;
end:
	return 0;
}

static
void setup_static_allocator(void)
{
	assert(cur_alloc.calloc == NULL);
	cur_alloc.calloc = static_calloc;
	assert(cur_alloc.malloc == NULL);
	cur_alloc.malloc = static_malloc;
	assert(cur_alloc.free == NULL);
	cur_alloc.free = static_free;
	assert(cur_alloc.realloc == NULL);
	cur_alloc.realloc = static_realloc;
	assert(cur_alloc.memalign == NULL);
	cur_alloc.memalign = static_memalign;
	assert(cur_alloc.posix_memalign == NULL);
	cur_alloc.posix_memalign = static_posix_memalign;
}

static
void lookup_all_symbols(void)
{
	struct alloc_functions af;

	/*
	 * Temporarily redirect allocation functions to
	 * static_calloc_aligned, and free function to static_free
	 * (no-op), until the dlsym lookup has completed.
	 */
	setup_static_allocator();

	/* Perform the actual lookups */
	af.calloc = dlsym(RTLD_NEXT, "calloc");
	af.malloc = dlsym(RTLD_NEXT, "malloc");
	af.free = dlsym(RTLD_NEXT, "free");
	af.realloc = dlsym(RTLD_NEXT, "realloc");
	af.memalign = dlsym(RTLD_NEXT, "memalign");
	af.posix_memalign = dlsym(RTLD_NEXT, "posix_memalign");

	/* Populate the new allocator functions */
	memcpy(&cur_alloc, &af, sizeof(cur_alloc));
}

void *malloc(size_t size)
{
	void *retval;

	URCU_TLS(malloc_nesting)++;
	if (cur_alloc.malloc == NULL) {
		lookup_all_symbols();
		if (cur_alloc.malloc == NULL) {
			fprintf(stderr, "mallocwrap: unable to find malloc\n");
			abort();
		}
	}
	retval = cur_alloc.malloc(size);
	if (URCU_TLS(malloc_nesting) == 1) {
		tracepoint(lttng_ust_libc, malloc,
			size, retval, LTTNG_UST_CALLER_IP());
	}
	URCU_TLS(malloc_nesting)--;
	return retval;
}

void free(void *ptr)
{
	URCU_TLS(malloc_nesting)++;
	/*
	 * Check whether the memory was allocated with
	 * static_calloc_align, in which case there is nothing to free.
	 */
	if (caa_unlikely((char *)ptr >= static_calloc_buf &&
			(char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN)) {
		goto end;
	}

	if (URCU_TLS(malloc_nesting) == 1) {
		tracepoint(lttng_ust_libc, free,
			ptr, LTTNG_UST_CALLER_IP());
	}

	if (cur_alloc.free == NULL) {
		lookup_all_symbols();
		if (cur_alloc.free == NULL) {
			fprintf(stderr, "mallocwrap: unable to find free\n");
			abort();
		}
	}
	cur_alloc.free(ptr);
end:
	URCU_TLS(malloc_nesting)--;
}

void *calloc(size_t nmemb, size_t size)
{
	void *retval;

	URCU_TLS(malloc_nesting)++;
	if (cur_alloc.calloc == NULL) {
		lookup_all_symbols();
		if (cur_alloc.calloc == NULL) {
			fprintf(stderr, "callocwrap: unable to find calloc\n");
			abort();
		}
	}
	retval = cur_alloc.calloc(nmemb, size);
	if (URCU_TLS(malloc_nesting) == 1) {
		tracepoint(lttng_ust_libc, calloc,
			nmemb, size, retval, LTTNG_UST_CALLER_IP());
	}
	URCU_TLS(malloc_nesting)--;
	return retval;
}

void *realloc(void *ptr, size_t size)
{
	void *retval;

	URCU_TLS(malloc_nesting)++;
	/*
	 * Check whether the memory was allocated with
	 * static_calloc_align, in which case there is nothing
	 * to free, and we need to copy the old data.
	 */
	if (caa_unlikely((char *)ptr >= static_calloc_buf &&
			(char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN)) {
		size_t *old_size;

		old_size = (size_t *) ptr - 1;
		if (cur_alloc.calloc == NULL) {
			lookup_all_symbols();
			if (cur_alloc.calloc == NULL) {
				fprintf(stderr, "reallocwrap: unable to find calloc\n");
				abort();
			}
		}
		retval = cur_alloc.calloc(1, size);
		if (retval) {
			memcpy(retval, ptr, *old_size);
		}
		/*
		 * Mimick that a NULL pointer has been received, so
		 * memory allocation analysis based on the trace don't
		 * get confused by the address from the static
		 * allocator.
		 */
		ptr = NULL;
		goto end;
	}

	if (cur_alloc.realloc == NULL) {
		lookup_all_symbols();
		if (cur_alloc.realloc == NULL) {
			fprintf(stderr, "reallocwrap: unable to find realloc\n");
			abort();
		}
	}
	retval = cur_alloc.realloc(ptr, size);
end:
	if (URCU_TLS(malloc_nesting) == 1) {
		tracepoint(lttng_ust_libc, realloc,
			ptr, size, retval, LTTNG_UST_CALLER_IP());
	}
	URCU_TLS(malloc_nesting)--;
	return retval;
}

void *memalign(size_t alignment, size_t size)
{
	void *retval;

	URCU_TLS(malloc_nesting)++;
	if (cur_alloc.memalign == NULL) {
		lookup_all_symbols();
		if (cur_alloc.memalign == NULL) {
			fprintf(stderr, "memalignwrap: unable to find memalign\n");
			abort();
		}
	}
	retval = cur_alloc.memalign(alignment, size);
	if (URCU_TLS(malloc_nesting) == 1) {
		tracepoint(lttng_ust_libc, memalign,
			alignment, size, retval,
			LTTNG_UST_CALLER_IP());
	}
	URCU_TLS(malloc_nesting)--;
	return retval;
}

int posix_memalign(void **memptr, size_t alignment, size_t size)
{
	int retval;

	URCU_TLS(malloc_nesting)++;
	if (cur_alloc.posix_memalign == NULL) {
		lookup_all_symbols();
		if (cur_alloc.posix_memalign == NULL) {
			fprintf(stderr, "posix_memalignwrap: unable to find posix_memalign\n");
			abort();
		}
	}
	retval = cur_alloc.posix_memalign(memptr, alignment, size);
	if (URCU_TLS(malloc_nesting) == 1) {
		tracepoint(lttng_ust_libc, posix_memalign,
			*memptr, alignment, size,
			retval, LTTNG_UST_CALLER_IP());
	}
	URCU_TLS(malloc_nesting)--;
	return retval;
}

static
void lttng_ust_fixup_malloc_nesting_tls(void)
{
	asm volatile ("" : : "m" (URCU_TLS(malloc_nesting)));
}

__attribute__((constructor))
void lttng_ust_malloc_wrapper_init(void)
{
	/* Initialization already done */
	if (cur_alloc.calloc) {
		return;
	}
	lttng_ust_fixup_malloc_nesting_tls();
	/*
	 * Ensure the allocator is in place before the process becomes
	 * multithreaded.
	 */
	lookup_all_symbols();
}
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2009 Pierre-Marc Fournier
	3	* Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	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
	20	#define _GNU_SOURCE
	21	#include <lttng/ust-dlfcn.h>
	22	#include <sys/types.h>
	23	#include <stdio.h>
	24	#include <assert.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>
	31	#include <helper.h>
	32
	33	#define TRACEPOINT_DEFINE
	34	#define TRACEPOINT_CREATE_PROBES
	35	#define TP_IP_PARAM ip
	36	#include "ust_libc.h"
	37
	38	#define STATIC_CALLOC_LEN 4096
	39	static char static_calloc_buf[STATIC_CALLOC_LEN];
	40	static unsigned long static_calloc_buf_offset;
	41
	42	struct alloc_functions {
	43	void (calloc)(size_t nmemb, size_t size);
	44	void (malloc)(size_t size);
	45	void (free)(void ptr);
	46	void (realloc)(void *ptr, size_t size);
	47	void (memalign)(size_t alignment, size_t size);
	48	int (posix_memalign)(void *memptr, size_t alignment, size_t size);
	49	};
	50
	51	static
	52	struct alloc_functions cur_alloc;
	53
	54	/*
	55	* Make sure our own use of the LTS compat layer will not cause infinite
	56	* recursion by calling calloc.
	57	*/
	58
	59	static
	60	void *static_calloc(size_t nmemb, size_t size);
	61
	62	/*
	63	* pthread mutex replacement for URCU tls compat layer.
	64	*/
	65	static int ust_malloc_lock;
	66
	67	static __attribute__((unused))
	68	void ust_malloc_spin_lock(pthread_mutex_t *lock)
	69	{
	70	/*
	71	* The memory barrier within cmpxchg takes care of ordering
	72	* memory accesses with respect to the start of the critical
	73	* section.
	74	*/
	75	while (uatomic_cmpxchg(&ust_malloc_lock, 0, 1) != 0)
	76	caa_cpu_relax();
	77	}
	78
	79	static __attribute__((unused))
	80	void ust_malloc_spin_unlock(pthread_mutex_t *lock)
	81	{
	82	/*
	83	* Ensure memory accesses within the critical section do not
	84	* leak outside.
	85	*/
	86	cmm_smp_mb();
	87	uatomic_set(&ust_malloc_lock, 0);
	88	}
	89
	90	#define calloc static_calloc
	91	#define pthread_mutex_lock ust_malloc_spin_lock
	92	#define pthread_mutex_unlock ust_malloc_spin_unlock
	93	static DEFINE_URCU_TLS(int, malloc_nesting);
	94	#undef ust_malloc_spin_unlock
	95	#undef ust_malloc_spin_lock
	96	#undef calloc
	97
	98	/*
	99	* Static allocator to use when initially executing dlsym(). It keeps a
	100	* size_t value of each object size prior to the object.
	101	*/
	102	static
	103	void *static_calloc_aligned(size_t nmemb, size_t size, size_t alignment)
	104	{
	105	size_t prev_offset, new_offset, res_offset, aligned_offset;
	106
	107	if (nmemb * size == 0) {
	108	return NULL;
	109	}
	110
	111	/*
	112	* Protect static_calloc_buf_offset from concurrent updates
	113	* using a cmpxchg loop rather than a mutex to remove a
	114	* dependency on pthread. This will minimize the risk of bad
	115	* interaction between mutex and malloc instrumentation.
	116	*/
	117	res_offset = CMM_LOAD_SHARED(static_calloc_buf_offset);
	118	do {
	119	prev_offset = res_offset;
	120	aligned_offset = ALIGN(prev_offset + sizeof(size_t), alignment);
	121	new_offset = aligned_offset + nmemb * size;
	122	if (new_offset > sizeof(static_calloc_buf)) {
	123	abort();
	124	}
	125	} while ((res_offset = uatomic_cmpxchg(&static_calloc_buf_offset,
	126	prev_offset, new_offset)) != prev_offset);
	127	(size_t ) &static_calloc_buf[aligned_offset - sizeof(size_t)] = size;
	128	return &static_calloc_buf[aligned_offset];
	129	}
	130
	131	static
	132	void *static_calloc(size_t nmemb, size_t size)
	133	{
	134	void *retval;
	135
	136	retval = static_calloc_aligned(nmemb, size, 1);
	137	return retval;
	138	}
	139
	140	static
	141	void *static_malloc(size_t size)
	142	{
	143	void *retval;
	144
	145	retval = static_calloc_aligned(1, size, 1);
	146	return retval;
	147	}
	148
	149	static
	150	void static_free(void *ptr)
	151	{
	152	/* no-op. */
	153	}
	154
	155	static
	156	void static_realloc(void ptr, size_t size)
	157	{
	158	size_t *old_size = NULL;
	159	void *retval;
	160
	161	if (size == 0) {
	162	retval = NULL;
	163	goto end;
	164	}
	165
	166	if (ptr) {
	167	old_size = (size_t *) ptr - 1;
	168	if (size <= *old_size) {
	169	/* We can re-use the old entry. */
	170	*old_size = size;
	171	retval = ptr;
	172	goto end;
	173	}
	174	}
	175	/* We need to expand. Don't free previous memory location. */
	176	retval = static_calloc_aligned(1, size, 1);
	177	assert(retval);
	178	if (ptr)
	179	memcpy(retval, ptr, *old_size);
	180	end:
	181	return retval;
	182	}
	183
	184	static
	185	void *static_memalign(size_t alignment, size_t size)
	186	{
	187	void *retval;
	188
	189	retval = static_calloc_aligned(1, size, alignment);
	190	return retval;
	191	}
	192
	193	static
	194	int static_posix_memalign(void **memptr, size_t alignment, size_t size)
	195	{
	196	void *ptr;
	197
	198	/* Check for power of 2, larger than void . /
	199	if (alignment & (alignment - 1)
	200	\|\| alignment < sizeof(void *)
	201	\|\| alignment == 0) {
	202	goto end;
	203	}
	204	ptr = static_calloc_aligned(1, size, alignment);
	205	*memptr = ptr;
	206	end:
	207	return 0;
	208	}
	209
	210	static
	211	void setup_static_allocator(void)
	212	{
	213	assert(cur_alloc.calloc == NULL);
	214	cur_alloc.calloc = static_calloc;
	215	assert(cur_alloc.malloc == NULL);
	216	cur_alloc.malloc = static_malloc;
	217	assert(cur_alloc.free == NULL);
	218	cur_alloc.free = static_free;
	219	assert(cur_alloc.realloc == NULL);
	220	cur_alloc.realloc = static_realloc;
	221	assert(cur_alloc.memalign == NULL);
	222	cur_alloc.memalign = static_memalign;
	223	assert(cur_alloc.posix_memalign == NULL);
	224	cur_alloc.posix_memalign = static_posix_memalign;
	225	}
	226
	227	static
	228	void lookup_all_symbols(void)
	229	{
	230	struct alloc_functions af;
	231
	232	/*
	233	* Temporarily redirect allocation functions to
	234	* static_calloc_aligned, and free function to static_free
	235	* (no-op), until the dlsym lookup has completed.
	236	*/
	237	setup_static_allocator();
	238
	239	/* Perform the actual lookups */
	240	af.calloc = dlsym(RTLD_NEXT, "calloc");
	241	af.malloc = dlsym(RTLD_NEXT, "malloc");
	242	af.free = dlsym(RTLD_NEXT, "free");
	243	af.realloc = dlsym(RTLD_NEXT, "realloc");
	244	af.memalign = dlsym(RTLD_NEXT, "memalign");
	245	af.posix_memalign = dlsym(RTLD_NEXT, "posix_memalign");
	246
	247	/* Populate the new allocator functions */
	248	memcpy(&cur_alloc, &af, sizeof(cur_alloc));
	249	}
	250
	251	void *malloc(size_t size)
	252	{
	253	void *retval;
	254
	255	URCU_TLS(malloc_nesting)++;
	256	if (cur_alloc.malloc == NULL) {
	257	lookup_all_symbols();
	258	if (cur_alloc.malloc == NULL) {
	259	fprintf(stderr, "mallocwrap: unable to find malloc\n");
	260	abort();
	261	}
	262	}
	263	retval = cur_alloc.malloc(size);
	264	if (URCU_TLS(malloc_nesting) == 1) {
	265	tracepoint(lttng_ust_libc, malloc,
	266	size, retval, LTTNG_UST_CALLER_IP());
	267	}
	268	URCU_TLS(malloc_nesting)--;
	269	return retval;
	270	}
	271
	272	void free(void *ptr)
	273	{
	274	URCU_TLS(malloc_nesting)++;
	275	/*
	276	* Check whether the memory was allocated with
	277	* static_calloc_align, in which case there is nothing to free.
	278	*/
	279	if (caa_unlikely((char *)ptr >= static_calloc_buf &&
	280	(char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN)) {
	281	goto end;
	282	}
	283
	284	if (URCU_TLS(malloc_nesting) == 1) {
	285	tracepoint(lttng_ust_libc, free,
	286	ptr, LTTNG_UST_CALLER_IP());
	287	}
	288
	289	if (cur_alloc.free == NULL) {
	290	lookup_all_symbols();
	291	if (cur_alloc.free == NULL) {
	292	fprintf(stderr, "mallocwrap: unable to find free\n");
	293	abort();
	294	}
	295	}
	296	cur_alloc.free(ptr);
	297	end:
	298	URCU_TLS(malloc_nesting)--;
	299	}
	300
	301	void *calloc(size_t nmemb, size_t size)
	302	{
	303	void *retval;
	304
	305	URCU_TLS(malloc_nesting)++;
	306	if (cur_alloc.calloc == NULL) {
	307	lookup_all_symbols();
	308	if (cur_alloc.calloc == NULL) {
	309	fprintf(stderr, "callocwrap: unable to find calloc\n");
	310	abort();
	311	}
	312	}
	313	retval = cur_alloc.calloc(nmemb, size);
	314	if (URCU_TLS(malloc_nesting) == 1) {
	315	tracepoint(lttng_ust_libc, calloc,
	316	nmemb, size, retval, LTTNG_UST_CALLER_IP());
	317	}
	318	URCU_TLS(malloc_nesting)--;
	319	return retval;
	320	}
	321
	322	void realloc(void ptr, size_t size)
	323	{
	324	void *retval;
	325
	326	URCU_TLS(malloc_nesting)++;
	327	/*
	328	* Check whether the memory was allocated with
	329	* static_calloc_align, in which case there is nothing
	330	* to free, and we need to copy the old data.
	331	*/
	332	if (caa_unlikely((char *)ptr >= static_calloc_buf &&
	333	(char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN)) {
	334	size_t *old_size;
	335
	336	old_size = (size_t *) ptr - 1;
	337	if (cur_alloc.calloc == NULL) {
	338	lookup_all_symbols();
	339	if (cur_alloc.calloc == NULL) {
	340	fprintf(stderr, "reallocwrap: unable to find calloc\n");
	341	abort();
	342	}
	343	}
	344	retval = cur_alloc.calloc(1, size);
	345	if (retval) {
	346	memcpy(retval, ptr, *old_size);
	347	}
	348	/*
	349	* Mimick that a NULL pointer has been received, so
	350	* memory allocation analysis based on the trace don't
	351	* get confused by the address from the static
	352	* allocator.
	353	*/
	354	ptr = NULL;
	355	goto end;
	356	}
	357
	358	if (cur_alloc.realloc == NULL) {
	359	lookup_all_symbols();
	360	if (cur_alloc.realloc == NULL) {
	361	fprintf(stderr, "reallocwrap: unable to find realloc\n");
	362	abort();
	363	}
	364	}
	365	retval = cur_alloc.realloc(ptr, size);
	366	end:
	367	if (URCU_TLS(malloc_nesting) == 1) {
	368	tracepoint(lttng_ust_libc, realloc,
	369	ptr, size, retval, LTTNG_UST_CALLER_IP());
	370	}
	371	URCU_TLS(malloc_nesting)--;
	372	return retval;
	373	}
	374
	375	void *memalign(size_t alignment, size_t size)
	376	{
	377	void *retval;
	378
	379	URCU_TLS(malloc_nesting)++;
	380	if (cur_alloc.memalign == NULL) {
	381	lookup_all_symbols();
	382	if (cur_alloc.memalign == NULL) {
	383	fprintf(stderr, "memalignwrap: unable to find memalign\n");
	384	abort();
	385	}
	386	}
	387	retval = cur_alloc.memalign(alignment, size);
	388	if (URCU_TLS(malloc_nesting) == 1) {
	389	tracepoint(lttng_ust_libc, memalign,
	390	alignment, size, retval,
	391	LTTNG_UST_CALLER_IP());
	392	}
	393	URCU_TLS(malloc_nesting)--;
	394	return retval;
	395	}
	396
	397	int posix_memalign(void **memptr, size_t alignment, size_t size)
	398	{
	399	int retval;
	400
	401	URCU_TLS(malloc_nesting)++;
	402	if (cur_alloc.posix_memalign == NULL) {
	403	lookup_all_symbols();
	404	if (cur_alloc.posix_memalign == NULL) {
	405	fprintf(stderr, "posix_memalignwrap: unable to find posix_memalign\n");
	406	abort();
	407	}
	408	}
	409	retval = cur_alloc.posix_memalign(memptr, alignment, size);
	410	if (URCU_TLS(malloc_nesting) == 1) {
	411	tracepoint(lttng_ust_libc, posix_memalign,
	412	*memptr, alignment, size,
	413	retval, LTTNG_UST_CALLER_IP());
	414	}
	415	URCU_TLS(malloc_nesting)--;
	416	return retval;
	417	}
	418
	419	static
	420	void lttng_ust_fixup_malloc_nesting_tls(void)
	421	{
	422	asm volatile ("" : : "m" (URCU_TLS(malloc_nesting)));
	423	}
	424
	425	__attribute__((constructor))
	426	void lttng_ust_malloc_wrapper_init(void)
	427	{
	428	/* Initialization already done */
	429	if (cur_alloc.calloc) {
	430	return;
	431	}
	432	lttng_ust_fixup_malloc_nesting_tls();
	433	/*
	434	* Ensure the allocator is in place before the process becomes
	435	* multithreaded.
	436	*/
	437	lookup_all_symbols();
	438	}