[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/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;
	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';

	switch (ev->loglevel_type) {
	case LTTNG_EVENT_LOGLEVEL:
		lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL;
		break;
	case LTTNG_EVENT_LOGLEVEL_ONLY:
		lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_ONLY;
		break;
	default:
		ERR("Unknown ust loglevel type (%d)", ev->type);
		goto error_free_event;
	}

	/* Copy loglevel name */
	strncpy(lue->attr.loglevel, ev->loglevel, LTTNG_UST_SYM_NAME_LEN);
	lue->attr.loglevel[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;
	enum lttng_ust_context_type utype;

	switch (ctx->ctx) {
	case LTTNG_EVENT_CONTEXT_VTID:
		utype = LTTNG_UST_CONTEXT_VTID;
		break;
	case LTTNG_EVENT_CONTEXT_VPID:
		utype = LTTNG_UST_CONTEXT_VPID;
		break;
	case LTTNG_EVENT_CONTEXT_PTHREAD_ID:
		utype = LTTNG_UST_CONTEXT_PTHREAD_ID;
		break;
	case LTTNG_EVENT_CONTEXT_PROCNAME:
		utype = LTTNG_UST_CONTEXT_PROCNAME;
		break;
	default:
		ERR("Invalid UST context");
		return NULL;
	}

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

	uctx->ctx.ctx = utype;
	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/common.h>
	25	#include <common/defaults.h>
	26
	27	#include "trace-ust.h"
	28
	29	/*
	30	* Find the channel in the hashtable.
	31	*/
	32	struct ltt_ust_channel trace_ust_find_channel_by_name(struct lttng_ht ht,
	33	char *name)
	34	{
	35	struct lttng_ht_node_str *node;
	36	struct lttng_ht_iter iter;
	37
	38	rcu_read_lock();
	39	lttng_ht_lookup(ht, (void *)name, &iter);
	40	node = lttng_ht_iter_get_node_str(&iter);
	41	if (node == NULL) {
	42	rcu_read_unlock();
	43	goto error;
	44	}
	45	rcu_read_unlock();
	46
	47	DBG2("Trace UST channel %s found by name", name);
	48
	49	return caa_container_of(node, struct ltt_ust_channel, node);
	50
	51	error:
	52	DBG2("Trace UST channel %s not found by name", name);
	53	return NULL;
	54	}
	55
	56	/*
	57	* Find the event in the hashtable.
	58	*/
	59	struct ltt_ust_event trace_ust_find_event_by_name(struct lttng_ht ht,
	60	char *name)
	61	{
	62	struct lttng_ht_node_str *node;
	63	struct lttng_ht_iter iter;
	64
	65	rcu_read_lock();
	66	lttng_ht_lookup(ht, (void *) name, &iter);
	67	node = lttng_ht_iter_get_node_str(&iter);
	68	if (node == NULL) {
	69	rcu_read_unlock();
	70	goto error;
	71	}
	72	rcu_read_unlock();
	73
	74	DBG2("Trace UST event found by name %s", name);
	75
	76	return caa_container_of(node, struct ltt_ust_event, node);
	77
	78	error:
	79	DBG2("Trace UST event NOT found by name %s", name);
	80	return NULL;
	81	}
	82
	83	/*
	84	* Allocate and initialize a ust session data structure.
	85	*
	86	* Return pointer to structure or NULL.
	87	*/
	88	struct ltt_ust_session trace_ust_create_session(char path, int session_id,
	89	struct lttng_domain *domain)
	90	{
	91	int ret;
	92	struct ltt_ust_session *lus;
	93
	94	/* Allocate a new ltt ust session */
	95	lus = zmalloc(sizeof(struct ltt_ust_session));
	96	if (lus == NULL) {
	97	PERROR("create ust session zmalloc");
	98	goto error;
	99	}
	100
	101	/* Init data structure */
	102	lus->id = session_id;
	103	lus->start_trace = 0;
	104
	105	/* Alloc UST domain hash tables */
	106	lus->domain_pid = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
	107	lus->domain_exec = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
	108
	109	/* Alloc UST global domain channels' HT */
	110	lus->domain_global.channels = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
	111
	112	/* Set session path */
	113	ret = snprintf(lus->pathname, PATH_MAX, "%s/ust", path);
	114	if (ret < 0) {
	115	PERROR("snprintf kernel traces path");
	116	goto error_free_session;
	117	}
	118
	119	DBG2("UST trace session create successful");
	120
	121	return lus;
	122
	123	error_free_session:
	124	free(lus);
	125	error:
	126	return NULL;
	127	}
	128
	129	/*
	130	* Allocate and initialize a ust channel data structure.
	131	*
	132	* Return pointer to structure or NULL.
	133	*/
	134	struct ltt_ust_channel trace_ust_create_channel(struct lttng_channel chan,
	135	char *path)
	136	{
	137	int ret;
	138	struct ltt_ust_channel *luc;
	139
	140	luc = zmalloc(sizeof(struct ltt_ust_channel));
	141	if (luc == NULL) {
	142	perror("ltt_ust_channel zmalloc");
	143	goto error;
	144	}
	145
	146	/* Copy UST channel attributes */
	147	luc->attr.overwrite = chan->attr.overwrite;
	148	luc->attr.subbuf_size = chan->attr.subbuf_size;
	149	luc->attr.num_subbuf = chan->attr.num_subbuf;
	150	luc->attr.switch_timer_interval = chan->attr.switch_timer_interval;
	151	luc->attr.read_timer_interval = chan->attr.read_timer_interval;
	152	luc->attr.output = chan->attr.output;
	153
	154	/* Translate to UST output enum */
	155	switch (luc->attr.output) {
	156	default:
	157	luc->attr.output = LTTNG_UST_MMAP;
	158	break;
	159	}
	160
	161	/* Copy channel name */
	162	strncpy(luc->name, chan->name, sizeof(luc->name));
	163	luc->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
	164
	165	/* Init node */
	166	lttng_ht_node_init_str(&luc->node, luc->name);
	167	/* Alloc hash tables */
	168	luc->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
	169	luc->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
	170
	171	/* Set trace output path */
	172	ret = snprintf(luc->pathname, PATH_MAX, "%s", path);
	173	if (ret < 0) {
	174	perror("asprintf ust create channel");
	175	goto error_free_channel;
	176	}
	177
	178	DBG2("Trace UST channel %s created", luc->name);
	179
	180	return luc;
	181
	182	error_free_channel:
	183	free(luc);
	184	error:
	185	return NULL;
	186	}
	187
	188	/*
	189	* Allocate and initialize a ust event. Set name and event type.
	190	*
	191	* Return pointer to structure or NULL.
	192	*/
	193	struct ltt_ust_event trace_ust_create_event(struct lttng_event ev)
	194	{
	195	struct ltt_ust_event *lue;
	196
	197	lue = zmalloc(sizeof(struct ltt_ust_event));
	198	if (lue == NULL) {
	199	PERROR("ust event zmalloc");
	200	goto error;
	201	}
	202
	203	switch (ev->type) {
	204	case LTTNG_EVENT_PROBE:
	205	lue->attr.instrumentation = LTTNG_UST_PROBE;
	206	break;
	207	case LTTNG_EVENT_FUNCTION:
	208	lue->attr.instrumentation = LTTNG_UST_FUNCTION;
	209	break;
	210	case LTTNG_EVENT_FUNCTION_ENTRY:
	211	lue->attr.instrumentation = LTTNG_UST_FUNCTION;
	212	break;
	213	case LTTNG_EVENT_TRACEPOINT:
	214	lue->attr.instrumentation = LTTNG_UST_TRACEPOINT;
	215	break;
	216	default:
	217	ERR("Unknown ust instrumentation type (%d)", ev->type);
	218	goto error_free_event;
	219	}
	220
	221	/* Copy event name */
	222	strncpy(lue->attr.name, ev->name, LTTNG_UST_SYM_NAME_LEN);
	223	lue->attr.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
	224
	225	switch (ev->loglevel_type) {
	226	case LTTNG_EVENT_LOGLEVEL:
	227	lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL;
	228	break;
	229	case LTTNG_EVENT_LOGLEVEL_ONLY:
	230	lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_ONLY;
	231	break;
	232	default:
	233	ERR("Unknown ust loglevel type (%d)", ev->type);
	234	goto error_free_event;
	235	}
	236
	237	/* Copy loglevel name */
	238	strncpy(lue->attr.loglevel, ev->loglevel, LTTNG_UST_SYM_NAME_LEN);
	239	lue->attr.loglevel[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
	240
	241	/* Init node */
	242	lttng_ht_node_init_str(&lue->node, lue->attr.name);
	243	/* Alloc context hash tables */
	244	lue->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
	245
	246	DBG2("Trace UST event %s created", lue->attr.name);
	247
	248	return lue;
	249
	250	error_free_event:
	251	free(lue);
	252	error:
	253	return NULL;
	254	}
	255
	256	/*
	257	* Allocate and initialize a ust metadata.
	258	*
	259	* Return pointer to structure or NULL.
	260	*/
	261	struct ltt_ust_metadata trace_ust_create_metadata(char path)
	262	{
	263	int ret;
	264	struct ltt_ust_metadata *lum;
	265
	266	lum = zmalloc(sizeof(struct ltt_ust_metadata));
	267	if (lum == NULL) {
	268	perror("ust metadata zmalloc");
	269	goto error;
	270	}
	271
	272	/* Set default attributes */
	273	lum->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
	274	lum->attr.subbuf_size = DEFAULT_METADATA_SUBBUF_SIZE;
	275	lum->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
	276	lum->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
	277	lum->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
	278	lum->attr.output = LTTNG_UST_MMAP;
	279
	280	lum->handle = -1;
	281	/* Set metadata trace path */
	282	ret = snprintf(lum->pathname, PATH_MAX, "%s/metadata", path);
	283	if (ret < 0) {
	284	perror("asprintf ust metadata");
	285	goto error_free_metadata;
	286	}
	287
	288	return lum;
	289
	290	error_free_metadata:
	291	free(lum);
	292	error:
	293	return NULL;
	294	}
	295
	296	/*
	297	* Allocate and initialize an UST context.
	298	*
	299	* Return pointer to structure or NULL.
	300	*/
	301	struct ltt_ust_context *trace_ust_create_context(
	302	struct lttng_event_context *ctx)
	303	{
	304	struct ltt_ust_context *uctx;
	305	enum lttng_ust_context_type utype;
	306
	307	switch (ctx->ctx) {
	308	case LTTNG_EVENT_CONTEXT_VTID:
	309	utype = LTTNG_UST_CONTEXT_VTID;
	310	break;
	311	case LTTNG_EVENT_CONTEXT_VPID:
	312	utype = LTTNG_UST_CONTEXT_VPID;
	313	break;
	314	case LTTNG_EVENT_CONTEXT_PTHREAD_ID:
	315	utype = LTTNG_UST_CONTEXT_PTHREAD_ID;
	316	break;
	317	case LTTNG_EVENT_CONTEXT_PROCNAME:
	318	utype = LTTNG_UST_CONTEXT_PROCNAME;
	319	break;
	320	default:
	321	ERR("Invalid UST context");
	322	return NULL;
	323	}
	324
	325	uctx = zmalloc(sizeof(struct ltt_ust_context));
	326	if (uctx == NULL) {
	327	PERROR("zmalloc ltt_ust_context");
	328	goto error;
	329	}
	330
	331	uctx->ctx.ctx = utype;
	332	lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
	333
	334	return uctx;
	335
	336	error:
	337	return NULL;
	338	}
	339
	340	/*
	341	* RCU safe free context structure.
	342	*/
	343	static void destroy_context_rcu(struct rcu_head *head)
	344	{
	345	struct lttng_ht_node_ulong *node =
	346	caa_container_of(head, struct lttng_ht_node_ulong, head);
	347	struct ltt_ust_context *ctx =
	348	caa_container_of(node, struct ltt_ust_context, node);
	349
	350	free(ctx);
	351	}
	352
	353	/*
	354	* Cleanup UST context hash table.
	355	*/
	356	static void destroy_contexts(struct lttng_ht *ht)
	357	{
	358	int ret;
	359	struct lttng_ht_node_ulong *node;
	360	struct lttng_ht_iter iter;
	361
	362	cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
	363	ret = lttng_ht_del(ht, &iter);
	364	if (!ret) {
	365	call_rcu(&node->head, destroy_context_rcu);
	366	}
	367	}
	368
	369	lttng_ht_destroy(ht);
	370	}
	371
	372	/*
	373	* Cleanup ust event structure.
	374	*/
	375	void trace_ust_destroy_event(struct ltt_ust_event *event)
	376	{
	377	DBG2("Trace destroy UST event %s", event->attr.name);
	378	destroy_contexts(event->ctx);
	379
	380	free(event);
	381	}
	382
	383	/*
	384	* URCU intermediate call to complete destroy event.
	385	*/
	386	static void destroy_event_rcu(struct rcu_head *head)
	387	{
	388	struct lttng_ht_node_str *node =
	389	caa_container_of(head, struct lttng_ht_node_str, head);
	390	struct ltt_ust_event *event =
	391	caa_container_of(node, struct ltt_ust_event, node);
	392
	393	trace_ust_destroy_event(event);
	394	}
	395
	396	/*
	397	* Cleanup UST events hashtable.
	398	*/
	399	static void destroy_events(struct lttng_ht *events)
	400	{
	401	int ret;
	402	struct lttng_ht_node_str *node;
	403	struct lttng_ht_iter iter;
	404
	405	cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
	406	ret = lttng_ht_del(events, &iter);
	407	assert(!ret);
	408	call_rcu(&node->head, destroy_event_rcu);
	409	}
	410
	411	lttng_ht_destroy(events);
	412	}
	413
	414	/*
	415	* Cleanup ust channel structure.
	416	*/
	417	void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
	418	{
	419	DBG2("Trace destroy UST channel %s", channel->name);
	420
	421	rcu_read_lock();
	422
	423	/* Destroying all events of the channel */
	424	destroy_events(channel->events);
	425	/* Destroying all context of the channel */
	426	destroy_contexts(channel->ctx);
	427
	428	free(channel);
	429
	430	rcu_read_unlock();
	431	}
	432
	433	/*
	434	* URCU intermediate call to complete destroy channel.
	435	*/
	436	static void destroy_channel_rcu(struct rcu_head *head)
	437	{
	438	struct lttng_ht_node_str *node =
	439	caa_container_of(head, struct lttng_ht_node_str, head);
	440	struct ltt_ust_channel *channel =
	441	caa_container_of(node, struct ltt_ust_channel, node);
	442
	443	trace_ust_destroy_channel(channel);
	444	}
	445
	446	/*
	447	* Cleanup ust metadata structure.
	448	*/
	449	void trace_ust_destroy_metadata(struct ltt_ust_metadata *metadata)
	450	{
	451	DBG2("Trace UST destroy metadata %d", metadata->handle);
	452
	453	free(metadata);
	454	}
	455
	456	/*
	457	* Iterate over a hash table containing channels and cleanup safely.
	458	*/
	459	static void destroy_channels(struct lttng_ht *channels)
	460	{
	461	int ret;
	462	struct lttng_ht_node_str *node;
	463	struct lttng_ht_iter iter;
	464
	465	rcu_read_lock();
	466
	467	cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
	468	ret = lttng_ht_del(channels, &iter);
	469	assert(!ret);
	470	call_rcu(&node->head, destroy_channel_rcu);
	471	}
	472
	473	lttng_ht_destroy(channels);
	474
	475	rcu_read_unlock();
	476	}
	477
	478	/*
	479	* Cleanup UST pid domain.
	480	*/
	481	static void destroy_domain_pid(struct lttng_ht *ht)
	482	{
	483	int ret;
	484	struct lttng_ht_iter iter;
	485	struct ltt_ust_domain_pid *dpid;
	486
	487	cds_lfht_for_each_entry(ht->ht, &iter.iter, dpid, node.node) {
	488	ret = lttng_ht_del(ht , &iter);
	489	assert(!ret);
	490	destroy_channels(dpid->channels);
	491	}
	492
	493	lttng_ht_destroy(ht);
	494	}
	495
	496	/*
	497	* Cleanup UST exec name domain.
	498	*/
	499	static void destroy_domain_exec(struct lttng_ht *ht)
	500	{
	501	int ret;
	502	struct lttng_ht_iter iter;
	503	struct ltt_ust_domain_exec *dexec;
	504
	505	cds_lfht_for_each_entry(ht->ht, &iter.iter, dexec, node.node) {
	506	ret = lttng_ht_del(ht , &iter);
	507	assert(!ret);
	508	destroy_channels(dexec->channels);
	509	}
	510
	511	lttng_ht_destroy(ht);
	512	}
	513
	514	/*
	515	* Cleanup UST global domain.
	516	*/
	517	static void destroy_domain_global(struct ltt_ust_domain_global *dom)
	518	{
	519	destroy_channels(dom->channels);
	520	}
	521
	522	/*
	523	* Cleanup ust session structure
	524	*/
	525	void trace_ust_destroy_session(struct ltt_ust_session *session)
	526	{
	527	/* Extra protection */
	528	if (session == NULL) {
	529	return;
	530	}
	531
	532	rcu_read_lock();
	533
	534	DBG2("Trace UST destroy session %d", session->id);
	535
	536	/* Cleaning up UST domain */
	537	destroy_domain_global(&session->domain_global);
	538	destroy_domain_pid(session->domain_pid);
	539	destroy_domain_exec(session->domain_exec);
	540
	541	free(session);
	542
	543	rcu_read_unlock();
	544	}