[lttng-ust.git] / liblttng-ust / lttng-probes.c

/*
 * lttng-probes.c
 *
 * Holds LTTng probes registry.
 *
 * Copyright 2010-2012 (c) - 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; only
 * version 2.1 of the License.
 *
 * 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
 */

#include <string.h>
#include <errno.h>
#include <urcu/list.h>
#include <urcu/hlist.h>
#include <lttng/ust-events.h>
#include <lttng/tracepoint.h>
#include "tracepoint-internal.h"
#include <assert.h>
#include <helper.h>
#include <ctype.h>

#include "lttng-tracer-core.h"
#include "jhash.h"
#include "error.h"

/*
 * probe list is protected by ust_lock()/ust_unlock().
 */
CDS_LIST_HEAD(probe_list);

struct cds_list_head *lttng_get_probe_list_head(void)
{
	return &probe_list;
}

static
const struct lttng_probe_desc *find_provider(const char *provider)
{
	struct lttng_probe_desc *iter;

	cds_list_for_each_entry(iter, &probe_list, head) {
		if (!strcmp(iter->provider, provider))
			return iter;
	}
	return NULL;
}

static
int check_event_provider(struct lttng_probe_desc *desc)
{
	int i;
	size_t provider_name_len;

	provider_name_len = strnlen(desc->provider,
				LTTNG_UST_SYM_NAME_LEN - 1);
	for (i = 0; i < desc->nr_events; i++) {
		if (strncmp(desc->event_desc[i]->name,
				desc->provider,
				provider_name_len))
			return 0;	/* provider mismatch */
	}
	return 1;
}

int lttng_probe_register(struct lttng_probe_desc *desc)
{
	struct lttng_probe_desc *iter;
	int ret = 0;
	int i;

	ust_lock();

	/*
	 * Check if the provider has already been registered.
	 */
	if (find_provider(desc->provider)) {
		ret = -EEXIST;
		goto end;
	}

	/*
	 * Each provider enforce that every event name begins with the
	 * provider name. Check this in an assertion for extra
	 * carefulness. This ensures we cannot have duplicate event
	 * names across providers.
	 */
	assert(check_event_provider(desc));

	/*
	 * The provider ensures there are no duplicate event names.
	 * Duplicated TRACEPOINT_EVENT event names would generate a
	 * compile-time error due to duplicated symbol names.
	 */

	/*
	 * We sort the providers by struct lttng_probe_desc pointer
	 * address.
	 */
	cds_list_for_each_entry_reverse(iter, &probe_list, head) {
		BUG_ON(iter == desc); /* Should never be in the list twice */
		if (iter < desc) {
			/* We belong to the location right after iter. */
			cds_list_add(&desc->head, &iter->head);
			goto desc_added;
		}
	}
	/* We should be added at the head of the list */
	cds_list_add(&desc->head, &probe_list);
desc_added:
	DBG("just registered probe %s containing %u events",
		desc->provider, desc->nr_events);
	/*
	 * fix the events awaiting probe load.
	 */
	for (i = 0; i < desc->nr_events; i++) {
		const struct lttng_event_desc *ed;

		ed = desc->event_desc[i];
		DBG("Registered event probe \"%s\" with signature \"%s\"",
			ed->name, ed->signature);
		ret = lttng_fix_pending_event_desc(ed);
		assert(!ret);
	}
end:
	ust_unlock();
	return ret;
}

/* Backward compatibility with UST 2.0 */
int ltt_probe_register(struct lttng_probe_desc *desc)
{
	return lttng_probe_register(desc);
}

void lttng_probe_unregister(struct lttng_probe_desc *desc)
{
	ust_lock();
	cds_list_del(&desc->head);
	DBG("just unregistered probe %s", desc->provider);
	ust_unlock();
}

/* Backward compatibility with UST 2.0 */
void ltt_probe_unregister(struct lttng_probe_desc *desc)
{
	lttng_probe_unregister(desc);
}

void lttng_probes_prune_event_list(struct lttng_ust_tracepoint_list *list)
{
	struct tp_list_entry *list_entry, *tmp;

	cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) {
		cds_list_del(&list_entry->head);
		free(list_entry);
	}
}

/*
 * called with UST lock held.
 */
int lttng_probes_get_event_list(struct lttng_ust_tracepoint_list *list)
{
	struct lttng_probe_desc *probe_desc;
	int i;

	CDS_INIT_LIST_HEAD(&list->head);
	cds_list_for_each_entry(probe_desc, &probe_list, head) {
		for (i = 0; i < probe_desc->nr_events; i++) {
			struct tp_list_entry *list_entry;

			list_entry = zmalloc(sizeof(*list_entry));
			if (!list_entry)
				goto err_nomem;
			cds_list_add(&list_entry->head, &list->head);
			strncpy(list_entry->tp.name,
				probe_desc->event_desc[i]->name,
				LTTNG_UST_SYM_NAME_LEN);
			list_entry->tp.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
			if (!probe_desc->event_desc[i]->loglevel) {
				list_entry->tp.loglevel = TRACE_DEFAULT;
			} else {
				list_entry->tp.loglevel = *(*probe_desc->event_desc[i]->loglevel);
			}
		}
	}
	if (cds_list_empty(&list->head))
		list->iter = NULL;
	else
		list->iter =
			cds_list_first_entry(&list->head, struct tp_list_entry, head);
	return 0;

err_nomem:
	lttng_probes_prune_event_list(list);
	return -ENOMEM;
}

/*
 * Return current iteration position, advance internal iterator to next.
 * Return NULL if end of list.
 */
struct lttng_ust_tracepoint_iter *
	lttng_ust_tracepoint_list_get_iter_next(struct lttng_ust_tracepoint_list *list)
{
	struct tp_list_entry *entry;

	if (!list->iter)
		return NULL;
	entry = list->iter;
	if (entry->head.next == &list->head)
		list->iter = NULL;
	else
		list->iter = cds_list_entry(entry->head.next,
				struct tp_list_entry, head);
	return &entry->tp;
}

void lttng_probes_prune_field_list(struct lttng_ust_field_list *list)
{
	struct tp_field_list_entry *list_entry, *tmp;

	cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) {
		cds_list_del(&list_entry->head);
		free(list_entry);
	}
}

/*
 * called with UST lock held.
 */
int lttng_probes_get_field_list(struct lttng_ust_field_list *list)
{
	struct lttng_probe_desc *probe_desc;
	int i;

	CDS_INIT_LIST_HEAD(&list->head);
	cds_list_for_each_entry(probe_desc, &probe_list, head) {
		for (i = 0; i < probe_desc->nr_events; i++) {
			const struct lttng_event_desc *event_desc =
				probe_desc->event_desc[i];
			int j;

			if (event_desc->nr_fields == 0) {
				/* Events without fields. */
				struct tp_field_list_entry *list_entry;

				list_entry = zmalloc(sizeof(*list_entry));
				if (!list_entry)
					goto err_nomem;
				cds_list_add(&list_entry->head, &list->head);
				strncpy(list_entry->field.event_name,
					event_desc->name,
					LTTNG_UST_SYM_NAME_LEN);
				list_entry->field.event_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
				list_entry->field.field_name[0] = '\0';
				list_entry->field.type = LTTNG_UST_FIELD_OTHER;
				if (!event_desc->loglevel) {
					list_entry->field.loglevel = TRACE_DEFAULT;
				} else {
					list_entry->field.loglevel = *(*event_desc->loglevel);
				}
				list_entry->field.nowrite = 1;
			}

			for (j = 0; j < event_desc->nr_fields; j++) {
				const struct lttng_event_field *event_field =
					&event_desc->fields[j];
				struct tp_field_list_entry *list_entry;

				list_entry = zmalloc(sizeof(*list_entry));
				if (!list_entry)
					goto err_nomem;
				cds_list_add(&list_entry->head, &list->head);
				strncpy(list_entry->field.event_name,
					event_desc->name,
					LTTNG_UST_SYM_NAME_LEN);
				list_entry->field.event_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
				strncpy(list_entry->field.field_name,
					event_field->name,
					LTTNG_UST_SYM_NAME_LEN);
				list_entry->field.field_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
				switch (event_field->type.atype) {
				case atype_integer:
					list_entry->field.type = LTTNG_UST_FIELD_INTEGER;
					break;
				case atype_string:
					list_entry->field.type = LTTNG_UST_FIELD_STRING;
					break;
				case atype_array:
					if (event_field->type.u.array.elem_type.atype != atype_integer
						|| event_field->type.u.array.elem_type.u.basic.integer.encoding == lttng_encode_none)
						list_entry->field.type = LTTNG_UST_FIELD_OTHER;
					else
						list_entry->field.type = LTTNG_UST_FIELD_STRING;
					break;
				case atype_sequence:
					if (event_field->type.u.sequence.elem_type.atype != atype_integer
						|| event_field->type.u.sequence.elem_type.u.basic.integer.encoding == lttng_encode_none)
						list_entry->field.type = LTTNG_UST_FIELD_OTHER;
					else
						list_entry->field.type = LTTNG_UST_FIELD_STRING;
					break;
				case atype_float:
					list_entry->field.type = LTTNG_UST_FIELD_FLOAT;
					break;
				case atype_enum:
					list_entry->field.type = LTTNG_UST_FIELD_ENUM;
					break;
				default:
					list_entry->field.type = LTTNG_UST_FIELD_OTHER;
				}
				if (!event_desc->loglevel) {
					list_entry->field.loglevel = TRACE_DEFAULT;
				} else {
					list_entry->field.loglevel = *(*event_desc->loglevel);
				}
				list_entry->field.nowrite = event_field->nowrite;
			}
		}
	}
	if (cds_list_empty(&list->head))
		list->iter = NULL;
	else
		list->iter =
			cds_list_first_entry(&list->head,
				struct tp_field_list_entry, head);
	return 0;

err_nomem:
	lttng_probes_prune_field_list(list);
	return -ENOMEM;
}

/*
 * Return current iteration position, advance internal iterator to next.
 * Return NULL if end of list.
 */
struct lttng_ust_field_iter *
	lttng_ust_field_list_get_iter_next(struct lttng_ust_field_list *list)
{
	struct tp_field_list_entry *entry;

	if (!list->iter)
		return NULL;
	entry = list->iter;
	if (entry->head.next == &list->head)
		list->iter = NULL;
	else
		list->iter = cds_list_entry(entry->head.next,
				struct tp_field_list_entry, head);
	return &entry->field;
}
Commit	Line	Data
ce5aef0b	1	/*
7dd08bec	2	* lttng-probes.c
ce5aef0b	3	*
ce5aef0b MD	4	* Holds LTTng probes registry.
ce5aef0b MD	5	*
e92f3e28 MD	6	* Copyright 2010-2012 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	7	*
	8	* This library is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; only
	11	* version 2.1 of the License.
	12	*
	13	* This library is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with this library; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
ce5aef0b MD	21	*/
ce5aef0b MD	22
8d8a24c8 MD	23	#include <string.h>
	24	#include <errno.h>
	25	#include <urcu/list.h>
1f18504e	26	#include <urcu/hlist.h>
4318ae1b	27	#include <lttng/ust-events.h>
902e1379	28	#include <lttng/tracepoint.h>
d8de1354	29	#include "tracepoint-internal.h"
a3bb4b27	30	#include <assert.h>
c8fcf224	31	#include <helper.h>
48740cab	32	#include <ctype.h>
ce5aef0b	33
7dd08bec	34	#include "lttng-tracer-core.h"
1f18504e MD	35	#include "jhash.h"
1f18504e MD	36	#include "error.h"
8165c8da MD	37
8165c8da MD	38	/*
17dfb34b	39	* probe list is protected by ust_lock()/ust_unlock().
8165c8da	40	*/
e58095ef MD	41	CDS_LIST_HEAD(probe_list);
	42
	43	struct cds_list_head *lttng_get_probe_list_head(void)
	44	{
	45	return &probe_list;
	46	}
ce5aef0b	47
df854e41 MD	48	static
	49	const struct lttng_probe_desc find_provider(const char provider)
	50	{
	51	struct lttng_probe_desc *iter;
	52
	53	cds_list_for_each_entry(iter, &probe_list, head) {
	54	if (!strcmp(iter->provider, provider))
	55	return iter;
	56	}
	57	return NULL;
	58	}
	59
ce5aef0b	60	static
48205d60	61	int check_event_provider(struct lttng_probe_desc *desc)
ce5aef0b	62	{
ce5aef0b	63	int i;
48205d60	64	size_t provider_name_len;
ce5aef0b	65
48205d60 MD	66	provider_name_len = strnlen(desc->provider,
	67	LTTNG_UST_SYM_NAME_LEN - 1);
	68	for (i = 0; i < desc->nr_events; i++) {
	69	if (strncmp(desc->event_desc[i]->name,
	70	desc->provider,
	71	provider_name_len))
	72	return 0; /* provider mismatch */
ce5aef0b	73	}
48205d60	74	return 1;
ce5aef0b MD	75	}
ce5aef0b MD	76
7dd08bec	77	int lttng_probe_register(struct lttng_probe_desc *desc)
ce5aef0b	78	{
df854e41	79	struct lttng_probe_desc *iter;
ce5aef0b MD	80	int ret = 0;
	81	int i;
	82
17dfb34b	83	ust_lock();
48205d60 MD	84
	85	/*
	86	* Check if the provider has already been registered.
	87	*/
df854e41 MD	88	if (find_provider(desc->provider)) {
	89	ret = -EEXIST;
	90	goto end;
	91	}
48205d60	92
ce5aef0b	93	/*
48205d60 MD	94	* Each provider enforce that every event name begins with the
	95	* provider name. Check this in an assertion for extra
	96	* carefulness. This ensures we cannot have duplicate event
	97	* names across providers.
	98	*/
	99	assert(check_event_provider(desc));
	100
	101	/*
	102	* The provider ensures there are no duplicate event names.
	103	* Duplicated TRACEPOINT_EVENT event names would generate a
	104	* compile-time error due to duplicated symbol names.
ce5aef0b	105	*/
df854e41 MD	106
	107	/*
	108	* We sort the providers by struct lttng_probe_desc pointer
	109	* address.
	110	*/
	111	cds_list_for_each_entry_reverse(iter, &probe_list, head) {
	112	BUG_ON(iter == desc); /* Should never be in the list twice */
	113	if (iter < desc) {
	114	/* We belong to the location right after iter. */
	115	cds_list_add(&desc->head, &iter->head);
	116	goto desc_added;
	117	}
	118	}
	119	/* We should be added at the head of the list */
8d8a24c8	120	cds_list_add(&desc->head, &probe_list);
df854e41	121	desc_added:
e81a53af MD	122	DBG("just registered probe %s containing %u events",
e81a53af MD	123	desc->provider, desc->nr_events);
8165c8da MD	124	/*
	125	* fix the events awaiting probe load.
	126	*/
	127	for (i = 0; i < desc->nr_events; i++) {
68755429 MD	128	const struct lttng_event_desc *ed;
	129
	130	ed = desc->event_desc[i];
	131	DBG("Registered event probe \"%s\" with signature \"%s\"",
	132	ed->name, ed->signature);
e58095ef	133	ret = lttng_fix_pending_event_desc(ed);
8165c8da MD	134	assert(!ret);
8165c8da MD	135	}
ce5aef0b	136	end:
17dfb34b	137	ust_unlock();
ce5aef0b MD	138	return ret;
ce5aef0b MD	139	}
ce5aef0b	140
7dd08bec MD	141	/* Backward compatibility with UST 2.0 */
	142	int ltt_probe_register(struct lttng_probe_desc *desc)
	143	{
	144	return lttng_probe_register(desc);
	145	}
	146
	147	void lttng_probe_unregister(struct lttng_probe_desc *desc)
ce5aef0b	148	{
17dfb34b	149	ust_lock();
8d8a24c8	150	cds_list_del(&desc->head);
e81a53af	151	DBG("just unregistered probe %s", desc->provider);
17dfb34b	152	ust_unlock();
ce5aef0b	153	}
ce5aef0b	154
7dd08bec MD	155	/* Backward compatibility with UST 2.0 */
	156	void ltt_probe_unregister(struct lttng_probe_desc *desc)
	157	{
	158	lttng_probe_unregister(desc);
	159	}
	160
7dd08bec	161	void lttng_probes_prune_event_list(struct lttng_ust_tracepoint_list *list)
c8fcf224 MD	162	{
	163	struct tp_list_entry list_entry, tmp;
	164
	165	cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) {
	166	cds_list_del(&list_entry->head);
	167	free(list_entry);
	168	}
	169	}
	170
	171	/*
	172	* called with UST lock held.
	173	*/
7dd08bec	174	int lttng_probes_get_event_list(struct lttng_ust_tracepoint_list *list)
c8fcf224 MD	175	{
	176	struct lttng_probe_desc *probe_desc;
	177	int i;
	178
	179	CDS_INIT_LIST_HEAD(&list->head);
	180	cds_list_for_each_entry(probe_desc, &probe_list, head) {
	181	for (i = 0; i < probe_desc->nr_events; i++) {
	182	struct tp_list_entry *list_entry;
	183
	184	list_entry = zmalloc(sizeof(*list_entry));
	185	if (!list_entry)
	186	goto err_nomem;
	187	cds_list_add(&list_entry->head, &list->head);
	188	strncpy(list_entry->tp.name,
	189	probe_desc->event_desc[i]->name,
	190	LTTNG_UST_SYM_NAME_LEN);
	191	list_entry->tp.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
	192	if (!probe_desc->event_desc[i]->loglevel) {
882a56d7	193	list_entry->tp.loglevel = TRACE_DEFAULT;
c8fcf224	194	} else {
882a56d7	195	list_entry->tp.loglevel = (probe_desc->event_desc[i]->loglevel);
c8fcf224 MD	196	}
	197	}
	198	}
	199	if (cds_list_empty(&list->head))
	200	list->iter = NULL;
	201	else
	202	list->iter =
	203	cds_list_first_entry(&list->head, struct tp_list_entry, head);
	204	return 0;
	205
	206	err_nomem:
7dd08bec	207	lttng_probes_prune_event_list(list);
c8fcf224 MD	208	return -ENOMEM;
	209	}
	210
	211	/*
	212	* Return current iteration position, advance internal iterator to next.
	213	* Return NULL if end of list.
	214	*/
	215	struct lttng_ust_tracepoint_iter *
	216	lttng_ust_tracepoint_list_get_iter_next(struct lttng_ust_tracepoint_list *list)
	217	{
	218	struct tp_list_entry *entry;
	219
	220	if (!list->iter)
	221	return NULL;
	222	entry = list->iter;
	223	if (entry->head.next == &list->head)
	224	list->iter = NULL;
	225	else
	226	list->iter = cds_list_entry(entry->head.next,
	227	struct tp_list_entry, head);
	228	return &entry->tp;
	229	}
1f18504e	230
7dd08bec	231	void lttng_probes_prune_field_list(struct lttng_ust_field_list *list)
06d4f27e MD	232	{
	233	struct tp_field_list_entry list_entry, tmp;
	234
	235	cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) {
	236	cds_list_del(&list_entry->head);
	237	free(list_entry);
	238	}
	239	}
	240
	241	/*
	242	* called with UST lock held.
	243	*/
7dd08bec	244	int lttng_probes_get_field_list(struct lttng_ust_field_list *list)
06d4f27e MD	245	{
	246	struct lttng_probe_desc *probe_desc;
	247	int i;
	248
	249	CDS_INIT_LIST_HEAD(&list->head);
	250	cds_list_for_each_entry(probe_desc, &probe_list, head) {
	251	for (i = 0; i < probe_desc->nr_events; i++) {
	252	const struct lttng_event_desc *event_desc =
	253	probe_desc->event_desc[i];
	254	int j;
	255
26329f26 MD	256	if (event_desc->nr_fields == 0) {
	257	/* Events without fields. */
	258	struct tp_field_list_entry *list_entry;
	259
	260	list_entry = zmalloc(sizeof(*list_entry));
	261	if (!list_entry)
	262	goto err_nomem;
	263	cds_list_add(&list_entry->head, &list->head);
	264	strncpy(list_entry->field.event_name,
	265	event_desc->name,
	266	LTTNG_UST_SYM_NAME_LEN);
	267	list_entry->field.event_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
	268	list_entry->field.field_name[0] = '\0';
	269	list_entry->field.type = LTTNG_UST_FIELD_OTHER;
	270	if (!event_desc->loglevel) {
	271	list_entry->field.loglevel = TRACE_DEFAULT;
	272	} else {
	273	list_entry->field.loglevel = (event_desc->loglevel);
	274	}
	275	list_entry->field.nowrite = 1;
	276	}
	277
06d4f27e MD	278	for (j = 0; j < event_desc->nr_fields; j++) {
	279	const struct lttng_event_field *event_field =
	280	&event_desc->fields[j];
	281	struct tp_field_list_entry *list_entry;
	282
	283	list_entry = zmalloc(sizeof(*list_entry));
	284	if (!list_entry)
	285	goto err_nomem;
	286	cds_list_add(&list_entry->head, &list->head);
	287	strncpy(list_entry->field.event_name,
	288	event_desc->name,
	289	LTTNG_UST_SYM_NAME_LEN);
	290	list_entry->field.event_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
	291	strncpy(list_entry->field.field_name,
	292	event_field->name,
	293	LTTNG_UST_SYM_NAME_LEN);
	294	list_entry->field.field_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
40003310 MD	295	switch (event_field->type.atype) {
	296	case atype_integer:
	297	list_entry->field.type = LTTNG_UST_FIELD_INTEGER;
	298	break;
	299	case atype_string:
	300	list_entry->field.type = LTTNG_UST_FIELD_STRING;
	301	break;
	302	case atype_array:
	303	if (event_field->type.u.array.elem_type.atype != atype_integer
	304	\|\| event_field->type.u.array.elem_type.u.basic.integer.encoding == lttng_encode_none)
	305	list_entry->field.type = LTTNG_UST_FIELD_OTHER;
	306	else
	307	list_entry->field.type = LTTNG_UST_FIELD_STRING;
	308	break;
	309	case atype_sequence:
	310	if (event_field->type.u.sequence.elem_type.atype != atype_integer
	311	\|\| event_field->type.u.sequence.elem_type.u.basic.integer.encoding == lttng_encode_none)
	312	list_entry->field.type = LTTNG_UST_FIELD_OTHER;
	313	else
	314	list_entry->field.type = LTTNG_UST_FIELD_STRING;
	315	break;
	316	case atype_float:
	317	list_entry->field.type = LTTNG_UST_FIELD_FLOAT;
	318	break;
	319	case atype_enum:
	320	list_entry->field.type = LTTNG_UST_FIELD_ENUM;
	321	break;
	322	default:
	323	list_entry->field.type = LTTNG_UST_FIELD_OTHER;
	324	}
06d4f27e MD	325	if (!event_desc->loglevel) {
	326	list_entry->field.loglevel = TRACE_DEFAULT;
	327	} else {
	328	list_entry->field.loglevel = (event_desc->loglevel);
	329	}
180901e6	330	list_entry->field.nowrite = event_field->nowrite;
06d4f27e MD	331	}
	332	}
	333	}
	334	if (cds_list_empty(&list->head))
	335	list->iter = NULL;
	336	else
	337	list->iter =
	338	cds_list_first_entry(&list->head,
	339	struct tp_field_list_entry, head);
	340	return 0;
	341
	342	err_nomem:
7dd08bec	343	lttng_probes_prune_field_list(list);
06d4f27e MD	344	return -ENOMEM;
	345	}
	346
	347	/*
	348	* Return current iteration position, advance internal iterator to next.
	349	* Return NULL if end of list.
	350	*/
	351	struct lttng_ust_field_iter *
	352	lttng_ust_field_list_get_iter_next(struct lttng_ust_field_list *list)
	353	{
	354	struct tp_field_list_entry *entry;
	355
	356	if (!list->iter)
	357	return NULL;
	358	entry = list->iter;
	359	if (entry->head.next == &list->head)
	360	list->iter = NULL;
	361	else
	362	list->iter = cds_list_entry(entry->head.next,
	363	struct tp_field_list_entry, head);
	364	return &entry->field;
	365	}