[lttng-tools.git] / src / bin / lttng-sessiond / trace-ust.c

/*
 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; only version 2 of the License.
 *
 * This program 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 General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <common/lttngerr.h>
#include <common/common.h>
#include <common/defaults.h>

#include "trace-ust.h"

/*
 * Find the channel in the hashtable.
 */
struct ltt_ust_channel *trace_ust_find_channel_by_name(struct lttng_ht *ht,
		char *name)
{
	struct lttng_ht_node_str *node;
	struct lttng_ht_iter iter;

	rcu_read_lock();
	lttng_ht_lookup(ht, (void *)name, &iter);
	node = lttng_ht_iter_get_node_str(&iter);
	if (node == NULL) {
		rcu_read_unlock();
		goto error;
	}
	rcu_read_unlock();

	DBG2("Trace UST channel %s found by name", name);

	return caa_container_of(node, struct ltt_ust_channel, node);

error:
	DBG2("Trace UST channel %s not found by name", name);
	return NULL;
}

/*
 * Find the event in the hashtable.
 */
struct ltt_ust_event *trace_ust_find_event_by_name(struct lttng_ht *ht,
		char *name)
{
	struct lttng_ht_node_str *node;
	struct lttng_ht_iter iter;

	rcu_read_lock();
	lttng_ht_lookup(ht, (void *) name, &iter);
	node = lttng_ht_iter_get_node_str(&iter);
	if (node == NULL) {
		rcu_read_unlock();
		goto error;
	}
	rcu_read_unlock();

	DBG2("Trace UST event found by name %s", name);

	return caa_container_of(node, struct ltt_ust_event, node);

error:
	DBG2("Trace UST event NOT found by name %s", name);
	return NULL;
}

/*
 * Allocate and initialize a ust session data structure.
 *
 * Return pointer to structure or NULL.
 */
struct ltt_ust_session *trace_ust_create_session(char *path, int session_id,
		struct lttng_domain *domain)
{
	int ret;
	struct ltt_ust_session *lus;

	/* Allocate a new ltt ust session */
	lus = zmalloc(sizeof(struct ltt_ust_session));
	if (lus == NULL) {
		PERROR("create ust session zmalloc");
		goto error;
	}

	/* Init data structure */
	lus->id = session_id;
	lus->start_trace = 0;

	/* Alloc UST domain hash tables */
	lus->domain_pid = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
	lus->domain_exec = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);

	/* Alloc UST global domain channels' HT */
	lus->domain_global.channels = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);

	/* Set session path */
	ret = snprintf(lus->pathname, PATH_MAX, "%s/ust", path);
	if (ret < 0) {
		PERROR("snprintf kernel traces path");
		goto error_free_session;
	}

	DBG2("UST trace session create successful");

	return lus;

error_free_session:
	free(lus);
error:
	return NULL;
}

/*
 * Allocate and initialize a ust channel data structure.
 *
 * Return pointer to structure or NULL.
 */
struct ltt_ust_channel *trace_ust_create_channel(struct lttng_channel *chan,
		char *path)
{
	int ret;
	struct ltt_ust_channel *luc;

	luc = zmalloc(sizeof(struct ltt_ust_channel));
	if (luc == NULL) {
		perror("ltt_ust_channel zmalloc");
		goto error;
	}

	/* Copy UST channel attributes */
	luc->attr.overwrite = chan->attr.overwrite;
	luc->attr.subbuf_size = chan->attr.subbuf_size;
	luc->attr.num_subbuf = chan->attr.num_subbuf;
	luc->attr.switch_timer_interval = chan->attr.switch_timer_interval;
	luc->attr.read_timer_interval = chan->attr.read_timer_interval;
	luc->attr.output = chan->attr.output;

	/* Translate to UST output enum */
	switch (luc->attr.output) {
	default:
		luc->attr.output = LTTNG_UST_MMAP;
		break;
	}

	/* Copy channel name */
	strncpy(luc->name, chan->name, sizeof(luc->name));
	luc->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';

	/* Init node */
	lttng_ht_node_init_str(&luc->node, luc->name);
	/* Alloc hash tables */
	luc->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
	luc->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);

	/* Set trace output path */
	ret = snprintf(luc->pathname, PATH_MAX, "%s", path);
	if (ret < 0) {
		perror("asprintf ust create channel");
		goto error_free_channel;
	}

	DBG2("Trace UST channel %s created", luc->name);

	return luc;

error_free_channel:
	free(luc);
error:
	return NULL;
}

/*
 * Allocate and initialize a ust event. Set name and event type.
 *
 * Return pointer to structure or NULL.
 */
struct ltt_ust_event *trace_ust_create_event(struct lttng_event *ev)
{
	struct ltt_ust_event *lue;

	lue = zmalloc(sizeof(struct ltt_ust_event));
	if (lue == NULL) {
		PERROR("ust event zmalloc");
		goto error;
	}

	switch (ev->type) {
	case LTTNG_EVENT_PROBE:
		lue->attr.instrumentation = LTTNG_UST_PROBE;
		break;
	case LTTNG_EVENT_FUNCTION:
		lue->attr.instrumentation = LTTNG_UST_FUNCTION;
		break;
	case LTTNG_EVENT_FUNCTION_ENTRY:
		lue->attr.instrumentation = LTTNG_UST_FUNCTION;
		break;
	case LTTNG_EVENT_TRACEPOINT:
		lue->attr.instrumentation = LTTNG_UST_TRACEPOINT;
		break;
	case LTTNG_EVENT_TRACEPOINT_LOGLEVEL:
		lue->attr.instrumentation = LTTNG_UST_TRACEPOINT_LOGLEVEL;
		break;
	default:
		ERR("Unknown ust instrumentation type (%d)", ev->type);
		goto error_free_event;
	}

	/* Copy event name */
	strncpy(lue->attr.name, ev->name, LTTNG_UST_SYM_NAME_LEN);
	lue->attr.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';

	/* Init node */
	lttng_ht_node_init_str(&lue->node, lue->attr.name);
	/* Alloc context hash tables */
	lue->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);

	DBG2("Trace UST event %s created", lue->attr.name);

	return lue;

error_free_event:
	free(lue);
error:
	return NULL;
}

/*
 * Allocate and initialize a ust metadata.
 *
 * Return pointer to structure or NULL.
 */
struct ltt_ust_metadata *trace_ust_create_metadata(char *path)
{
	int ret;
	struct ltt_ust_metadata *lum;

	lum = zmalloc(sizeof(struct ltt_ust_metadata));
	if (lum == NULL) {
		perror("ust metadata zmalloc");
		goto error;
	}

	/* Set default attributes */
	lum->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
	lum->attr.subbuf_size = DEFAULT_METADATA_SUBBUF_SIZE;
	lum->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
	lum->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
	lum->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
	lum->attr.output = LTTNG_UST_MMAP;

	lum->handle = -1;
	/* Set metadata trace path */
	ret = snprintf(lum->pathname, PATH_MAX, "%s/metadata", path);
	if (ret < 0) {
		perror("asprintf ust metadata");
		goto error_free_metadata;
	}

	return lum;

error_free_metadata:
	free(lum);
error:
	return NULL;
}

/*
 * Allocate and initialize an UST context.
 *
 * Return pointer to structure or NULL.
 */
struct ltt_ust_context *trace_ust_create_context(
		struct lttng_event_context *ctx)
{
	struct ltt_ust_context *uctx;

	uctx = zmalloc(sizeof(struct ltt_ust_context));
	if (uctx == NULL) {
		PERROR("zmalloc ltt_ust_context");
		goto error;
	}

	uctx->ctx.ctx = ctx->ctx;
	lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);

	return uctx;

error:
	return NULL;
}

/*
 * RCU safe free context structure.
 */
static void destroy_context_rcu(struct rcu_head *head)
{
	struct lttng_ht_node_ulong *node =
		caa_container_of(head, struct lttng_ht_node_ulong, head);
	struct ltt_ust_context *ctx =
		caa_container_of(node, struct ltt_ust_context, node);

	free(ctx);
}

/*
 * Cleanup UST context hash table.
 */
static void destroy_contexts(struct lttng_ht *ht)
{
	int ret;
	struct lttng_ht_node_ulong *node;
	struct lttng_ht_iter iter;

	cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
		ret = lttng_ht_del(ht, &iter);
		if (!ret) {
			call_rcu(&node->head, destroy_context_rcu);
		}
	}

	lttng_ht_destroy(ht);
}

/*
 * Cleanup ust event structure.
 */
void trace_ust_destroy_event(struct ltt_ust_event *event)
{
	DBG2("Trace destroy UST event %s", event->attr.name);
	destroy_contexts(event->ctx);

	free(event);
}

/*
 * URCU intermediate call to complete destroy event.
 */
static void destroy_event_rcu(struct rcu_head *head)
{
	struct lttng_ht_node_str *node =
		caa_container_of(head, struct lttng_ht_node_str, head);
	struct ltt_ust_event *event =
		caa_container_of(node, struct ltt_ust_event, node);

	trace_ust_destroy_event(event);
}

/*
 * Cleanup UST events hashtable.
 */
static void destroy_events(struct lttng_ht *events)
{
	int ret;
	struct lttng_ht_node_str *node;
	struct lttng_ht_iter iter;

	cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
		ret = lttng_ht_del(events, &iter);
		assert(!ret);
		call_rcu(&node->head, destroy_event_rcu);
	}

	lttng_ht_destroy(events);
}

/*
 * Cleanup ust channel structure.
 */
void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
{
	DBG2("Trace destroy UST channel %s", channel->name);

	rcu_read_lock();

	/* Destroying all events of the channel */
	destroy_events(channel->events);
	/* Destroying all context of the channel */
	destroy_contexts(channel->ctx);

	free(channel);

	rcu_read_unlock();
}

/*
 * URCU intermediate call to complete destroy channel.
 */
static void destroy_channel_rcu(struct rcu_head *head)
{
	struct lttng_ht_node_str *node =
		caa_container_of(head, struct lttng_ht_node_str, head);
	struct ltt_ust_channel *channel =
		caa_container_of(node, struct ltt_ust_channel, node);

	trace_ust_destroy_channel(channel);
}

/*
 * Cleanup ust metadata structure.
 */
void trace_ust_destroy_metadata(struct ltt_ust_metadata *metadata)
{
	DBG2("Trace UST destroy metadata %d", metadata->handle);

	free(metadata);
}

/*
 * Iterate over a hash table containing channels and cleanup safely.
 */
static void destroy_channels(struct lttng_ht *channels)
{
	int ret;
	struct lttng_ht_node_str *node;
	struct lttng_ht_iter iter;

	rcu_read_lock();

	cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
		ret = lttng_ht_del(channels, &iter);
		assert(!ret);
		call_rcu(&node->head, destroy_channel_rcu);
	}

	lttng_ht_destroy(channels);

	rcu_read_unlock();
}

/*
 * Cleanup UST pid domain.
 */
static void destroy_domain_pid(struct lttng_ht *ht)
{
	int ret;
	struct lttng_ht_iter iter;
	struct ltt_ust_domain_pid *dpid;

	cds_lfht_for_each_entry(ht->ht, &iter.iter, dpid, node.node) {
		ret = lttng_ht_del(ht , &iter);
		assert(!ret);
		destroy_channels(dpid->channels);
	}

	lttng_ht_destroy(ht);
}

/*
 * Cleanup UST exec name domain.
 */
static void destroy_domain_exec(struct lttng_ht *ht)
{
	int ret;
	struct lttng_ht_iter iter;
	struct ltt_ust_domain_exec *dexec;

	cds_lfht_for_each_entry(ht->ht, &iter.iter, dexec, node.node) {
		ret = lttng_ht_del(ht , &iter);
		assert(!ret);
		destroy_channels(dexec->channels);
	}

	lttng_ht_destroy(ht);
}

/*
 * Cleanup UST global domain.
 */
static void destroy_domain_global(struct ltt_ust_domain_global *dom)
{
	destroy_channels(dom->channels);
}

/*
 * Cleanup ust session structure
 */
void trace_ust_destroy_session(struct ltt_ust_session *session)
{
	/* Extra protection */
	if (session == NULL) {
		return;
	}

	rcu_read_lock();

	DBG2("Trace UST destroy session %d", session->id);

	/* Cleaning up UST domain */
	destroy_domain_global(&session->domain_global);
	destroy_domain_pid(session->domain_pid);
	destroy_domain_exec(session->domain_exec);

	free(session);

	rcu_read_unlock();
}
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
	3	*
	4	* This program is free software; you can redistribute it and/or modify it
	5	* under the terms of the GNU General Public License as published by the Free
	6	* Software Foundation; only version 2 of the License.
	7	*
	8	* This program is distributed in the hope that it will be useful, but WITHOUT
	9	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	10	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	11	* more details.
	12	*
	13	* You should have received a copy of the GNU General Public License along with
	14	* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
	15	* Place - Suite 330, Boston, MA 02111-1307, USA.
	16	*/
	17
	18	#define _GNU_SOURCE
	19	#include <stdio.h>
	20	#include <stdlib.h>
	21	#include <string.h>
	22	#include <unistd.h>
	23
	24	#include <common/lttngerr.h>
	25	#include <common/common.h>
	26	#include <common/defaults.h>
	27
	28	#include "trace-ust.h"
	29
	30	/*
	31	* Find the channel in the hashtable.
	32	*/
	33	struct ltt_ust_channel trace_ust_find_channel_by_name(struct lttng_ht ht,
	34	char *name)
	35	{
	36	struct lttng_ht_node_str *node;
	37	struct lttng_ht_iter iter;
	38
	39	rcu_read_lock();
	40	lttng_ht_lookup(ht, (void *)name, &iter);
	41	node = lttng_ht_iter_get_node_str(&iter);
	42	if (node == NULL) {
	43	rcu_read_unlock();
	44	goto error;
	45	}
	46	rcu_read_unlock();
	47
	48	DBG2("Trace UST channel %s found by name", name);
	49
	50	return caa_container_of(node, struct ltt_ust_channel, node);
	51
	52	error:
	53	DBG2("Trace UST channel %s not found by name", name);
	54	return NULL;
	55	}
	56
	57	/*
	58	* Find the event in the hashtable.
	59	*/
	60	struct ltt_ust_event trace_ust_find_event_by_name(struct lttng_ht ht,
	61	char *name)
	62	{
	63	struct lttng_ht_node_str *node;
	64	struct lttng_ht_iter iter;
	65
	66	rcu_read_lock();
	67	lttng_ht_lookup(ht, (void *) name, &iter);
	68	node = lttng_ht_iter_get_node_str(&iter);
	69	if (node == NULL) {
	70	rcu_read_unlock();
	71	goto error;
	72	}
	73	rcu_read_unlock();
	74
	75	DBG2("Trace UST event found by name %s", name);
	76
	77	return caa_container_of(node, struct ltt_ust_event, node);
	78
	79	error:
	80	DBG2("Trace UST event NOT found by name %s", name);
	81	return NULL;
	82	}
	83
	84	/*
	85	* Allocate and initialize a ust session data structure.
	86	*
	87	* Return pointer to structure or NULL.
	88	*/
	89	struct ltt_ust_session trace_ust_create_session(char path, int session_id,
	90	struct lttng_domain *domain)
	91	{
	92	int ret;
	93	struct ltt_ust_session *lus;
	94
	95	/* Allocate a new ltt ust session */
	96	lus = zmalloc(sizeof(struct ltt_ust_session));
	97	if (lus == NULL) {
	98	PERROR("create ust session zmalloc");
	99	goto error;
	100	}
	101
	102	/* Init data structure */
	103	lus->id = session_id;
	104	lus->start_trace = 0;
	105
	106	/* Alloc UST domain hash tables */
	107	lus->domain_pid = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
	108	lus->domain_exec = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
	109
	110	/* Alloc UST global domain channels' HT */
	111	lus->domain_global.channels = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
	112
	113	/* Set session path */
	114	ret = snprintf(lus->pathname, PATH_MAX, "%s/ust", path);
	115	if (ret < 0) {
	116	PERROR("snprintf kernel traces path");
	117	goto error_free_session;
	118	}
	119
	120	DBG2("UST trace session create successful");
	121
	122	return lus;
	123
	124	error_free_session:
	125	free(lus);
	126	error:
	127	return NULL;
	128	}
	129
	130	/*
	131	* Allocate and initialize a ust channel data structure.
	132	*
	133	* Return pointer to structure or NULL.
	134	*/
	135	struct ltt_ust_channel trace_ust_create_channel(struct lttng_channel chan,
	136	char *path)
	137	{
	138	int ret;
	139	struct ltt_ust_channel *luc;
	140
	141	luc = zmalloc(sizeof(struct ltt_ust_channel));
	142	if (luc == NULL) {
	143	perror("ltt_ust_channel zmalloc");
	144	goto error;
	145	}
	146
	147	/* Copy UST channel attributes */
	148	luc->attr.overwrite = chan->attr.overwrite;
	149	luc->attr.subbuf_size = chan->attr.subbuf_size;
	150	luc->attr.num_subbuf = chan->attr.num_subbuf;
	151	luc->attr.switch_timer_interval = chan->attr.switch_timer_interval;
	152	luc->attr.read_timer_interval = chan->attr.read_timer_interval;
	153	luc->attr.output = chan->attr.output;
	154
	155	/* Translate to UST output enum */
	156	switch (luc->attr.output) {
	157	default:
	158	luc->attr.output = LTTNG_UST_MMAP;
	159	break;
	160	}
	161
	162	/* Copy channel name */
	163	strncpy(luc->name, chan->name, sizeof(luc->name));
	164	luc->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
	165
	166	/* Init node */
	167	lttng_ht_node_init_str(&luc->node, luc->name);
	168	/* Alloc hash tables */
	169	luc->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
	170	luc->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
	171
	172	/* Set trace output path */
	173	ret = snprintf(luc->pathname, PATH_MAX, "%s", path);
	174	if (ret < 0) {
	175	perror("asprintf ust create channel");
	176	goto error_free_channel;
	177	}
	178
	179	DBG2("Trace UST channel %s created", luc->name);
	180
	181	return luc;
	182
	183	error_free_channel:
	184	free(luc);
	185	error:
	186	return NULL;
	187	}
	188
	189	/*
	190	* Allocate and initialize a ust event. Set name and event type.
	191	*
	192	* Return pointer to structure or NULL.
	193	*/
	194	struct ltt_ust_event trace_ust_create_event(struct lttng_event ev)
	195	{
	196	struct ltt_ust_event *lue;
	197
	198	lue = zmalloc(sizeof(struct ltt_ust_event));
	199	if (lue == NULL) {
	200	PERROR("ust event zmalloc");
	201	goto error;
	202	}
	203
	204	switch (ev->type) {
	205	case LTTNG_EVENT_PROBE:
	206	lue->attr.instrumentation = LTTNG_UST_PROBE;
	207	break;
	208	case LTTNG_EVENT_FUNCTION:
	209	lue->attr.instrumentation = LTTNG_UST_FUNCTION;
	210	break;
	211	case LTTNG_EVENT_FUNCTION_ENTRY:
	212	lue->attr.instrumentation = LTTNG_UST_FUNCTION;
	213	break;
	214	case LTTNG_EVENT_TRACEPOINT:
	215	lue->attr.instrumentation = LTTNG_UST_TRACEPOINT;
	216	break;
	217	case LTTNG_EVENT_TRACEPOINT_LOGLEVEL:
	218	lue->attr.instrumentation = LTTNG_UST_TRACEPOINT_LOGLEVEL;
	219	break;
	220	default:
	221	ERR("Unknown ust instrumentation type (%d)", ev->type);
	222	goto error_free_event;
	223	}
	224
	225	/* Copy event name */
	226	strncpy(lue->attr.name, ev->name, LTTNG_UST_SYM_NAME_LEN);
	227	lue->attr.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
	228
	229	/* Init node */
	230	lttng_ht_node_init_str(&lue->node, lue->attr.name);
	231	/* Alloc context hash tables */
	232	lue->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
	233
	234	DBG2("Trace UST event %s created", lue->attr.name);
	235
	236	return lue;
	237
	238	error_free_event:
	239	free(lue);
	240	error:
	241	return NULL;
	242	}
	243
	244	/*
	245	* Allocate and initialize a ust metadata.
	246	*
	247	* Return pointer to structure or NULL.
	248	*/
	249	struct ltt_ust_metadata trace_ust_create_metadata(char path)
	250	{
	251	int ret;
	252	struct ltt_ust_metadata *lum;
	253
	254	lum = zmalloc(sizeof(struct ltt_ust_metadata));
	255	if (lum == NULL) {
	256	perror("ust metadata zmalloc");
	257	goto error;
	258	}
	259
	260	/* Set default attributes */
	261	lum->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
	262	lum->attr.subbuf_size = DEFAULT_METADATA_SUBBUF_SIZE;
	263	lum->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
	264	lum->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
	265	lum->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
	266	lum->attr.output = LTTNG_UST_MMAP;
	267
	268	lum->handle = -1;
	269	/* Set metadata trace path */
	270	ret = snprintf(lum->pathname, PATH_MAX, "%s/metadata", path);
	271	if (ret < 0) {
	272	perror("asprintf ust metadata");
	273	goto error_free_metadata;
	274	}
	275
	276	return lum;
	277
	278	error_free_metadata:
	279	free(lum);
	280	error:
	281	return NULL;
	282	}
	283
	284	/*
	285	* Allocate and initialize an UST context.
	286	*
	287	* Return pointer to structure or NULL.
	288	*/
	289	struct ltt_ust_context *trace_ust_create_context(
	290	struct lttng_event_context *ctx)
	291	{
	292	struct ltt_ust_context *uctx;
	293
	294	uctx = zmalloc(sizeof(struct ltt_ust_context));
	295	if (uctx == NULL) {
	296	PERROR("zmalloc ltt_ust_context");
	297	goto error;
	298	}
	299
	300	uctx->ctx.ctx = ctx->ctx;
	301	lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
	302
	303	return uctx;
	304
	305	error:
	306	return NULL;
	307	}
	308
	309	/*
	310	* RCU safe free context structure.
	311	*/
	312	static void destroy_context_rcu(struct rcu_head *head)
	313	{
	314	struct lttng_ht_node_ulong *node =
	315	caa_container_of(head, struct lttng_ht_node_ulong, head);
	316	struct ltt_ust_context *ctx =
	317	caa_container_of(node, struct ltt_ust_context, node);
	318
	319	free(ctx);
	320	}
	321
	322	/*
	323	* Cleanup UST context hash table.
	324	*/
	325	static void destroy_contexts(struct lttng_ht *ht)
	326	{
	327	int ret;
	328	struct lttng_ht_node_ulong *node;
	329	struct lttng_ht_iter iter;
	330
	331	cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
	332	ret = lttng_ht_del(ht, &iter);
	333	if (!ret) {
	334	call_rcu(&node->head, destroy_context_rcu);
	335	}
	336	}
	337
	338	lttng_ht_destroy(ht);
	339	}
	340
	341	/*
	342	* Cleanup ust event structure.
	343	*/
	344	void trace_ust_destroy_event(struct ltt_ust_event *event)
	345	{
	346	DBG2("Trace destroy UST event %s", event->attr.name);
	347	destroy_contexts(event->ctx);
	348
	349	free(event);
	350	}
	351
	352	/*
	353	* URCU intermediate call to complete destroy event.
	354	*/
	355	static void destroy_event_rcu(struct rcu_head *head)
	356	{
	357	struct lttng_ht_node_str *node =
	358	caa_container_of(head, struct lttng_ht_node_str, head);
	359	struct ltt_ust_event *event =
	360	caa_container_of(node, struct ltt_ust_event, node);
	361
	362	trace_ust_destroy_event(event);
	363	}
	364
	365	/*
	366	* Cleanup UST events hashtable.
	367	*/
	368	static void destroy_events(struct lttng_ht *events)
	369	{
	370	int ret;
	371	struct lttng_ht_node_str *node;
	372	struct lttng_ht_iter iter;
	373
	374	cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
	375	ret = lttng_ht_del(events, &iter);
	376	assert(!ret);
	377	call_rcu(&node->head, destroy_event_rcu);
	378	}
	379
	380	lttng_ht_destroy(events);
	381	}
	382
	383	/*
	384	* Cleanup ust channel structure.
	385	*/
	386	void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
	387	{
	388	DBG2("Trace destroy UST channel %s", channel->name);
	389
	390	rcu_read_lock();
	391
	392	/* Destroying all events of the channel */
	393	destroy_events(channel->events);
	394	/* Destroying all context of the channel */
	395	destroy_contexts(channel->ctx);
	396
	397	free(channel);
	398
	399	rcu_read_unlock();
	400	}
	401
	402	/*
	403	* URCU intermediate call to complete destroy channel.
	404	*/
	405	static void destroy_channel_rcu(struct rcu_head *head)
	406	{
	407	struct lttng_ht_node_str *node =
	408	caa_container_of(head, struct lttng_ht_node_str, head);
	409	struct ltt_ust_channel *channel =
	410	caa_container_of(node, struct ltt_ust_channel, node);
	411
	412	trace_ust_destroy_channel(channel);
	413	}
	414
	415	/*
	416	* Cleanup ust metadata structure.
	417	*/
	418	void trace_ust_destroy_metadata(struct ltt_ust_metadata *metadata)
	419	{
	420	DBG2("Trace UST destroy metadata %d", metadata->handle);
	421
	422	free(metadata);
	423	}
	424
	425	/*
	426	* Iterate over a hash table containing channels and cleanup safely.
	427	*/
	428	static void destroy_channels(struct lttng_ht *channels)
	429	{
	430	int ret;
	431	struct lttng_ht_node_str *node;
	432	struct lttng_ht_iter iter;
	433
	434	rcu_read_lock();
	435
	436	cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
	437	ret = lttng_ht_del(channels, &iter);
	438	assert(!ret);
	439	call_rcu(&node->head, destroy_channel_rcu);
	440	}
	441
	442	lttng_ht_destroy(channels);
	443
	444	rcu_read_unlock();
	445	}
	446
	447	/*
	448	* Cleanup UST pid domain.
	449	*/
	450	static void destroy_domain_pid(struct lttng_ht *ht)
	451	{
	452	int ret;
	453	struct lttng_ht_iter iter;
	454	struct ltt_ust_domain_pid *dpid;
	455
	456	cds_lfht_for_each_entry(ht->ht, &iter.iter, dpid, node.node) {
	457	ret = lttng_ht_del(ht , &iter);
	458	assert(!ret);
	459	destroy_channels(dpid->channels);
	460	}
	461
	462	lttng_ht_destroy(ht);
	463	}
	464
	465	/*
	466	* Cleanup UST exec name domain.
	467	*/
	468	static void destroy_domain_exec(struct lttng_ht *ht)
	469	{
	470	int ret;
	471	struct lttng_ht_iter iter;
	472	struct ltt_ust_domain_exec *dexec;
	473
	474	cds_lfht_for_each_entry(ht->ht, &iter.iter, dexec, node.node) {
	475	ret = lttng_ht_del(ht , &iter);
	476	assert(!ret);
	477	destroy_channels(dexec->channels);
	478	}
	479
	480	lttng_ht_destroy(ht);
	481	}
	482
	483	/*
	484	* Cleanup UST global domain.
	485	*/
	486	static void destroy_domain_global(struct ltt_ust_domain_global *dom)
	487	{
	488	destroy_channels(dom->channels);
	489	}
	490
	491	/*
	492	* Cleanup ust session structure
	493	*/
	494	void trace_ust_destroy_session(struct ltt_ust_session *session)
	495	{
	496	/* Extra protection */
	497	if (session == NULL) {
	498	return;
	499	}
	500
	501	rcu_read_lock();
	502
	503	DBG2("Trace UST destroy session %d", session->id);
	504
	505	/* Cleaning up UST domain */
	506	destroy_domain_global(&session->domain_global);
	507	destroy_domain_pid(session->domain_pid);
	508	destroy_domain_exec(session->domain_exec);
	509
	510	free(session);
	511
	512	rcu_read_unlock();
	513	}