[lttng-ust.git] / src / lib / lttng-ust / lttng-probes.c

/*
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 * Copyright 2010-2012 (C) Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Holds LTTng probes registry.
 */

#define _LGPL_SOURCE
#include <string.h>
#include <errno.h>
#include <urcu/list.h>
#include <urcu/hlist.h>
#include <lttng/ust-events.h>
#include <lttng/tracepoint.h>
#include "common/tracepoint.h"
#include <assert.h>
#include "common/macros.h"
#include <ctype.h>

#include "lttng-tracer-core.h"
#include "common/jhash.h"
#include "lib/lttng-ust/events.h"

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

/*
 * List of probes registered by not yet processed.
 */
static CDS_LIST_HEAD(lazy_probe_init);

/*
 * lazy_nesting counter ensures we don't trigger lazy probe registration
 * fixup while we are performing the fixup. It is protected by the ust
 * mutex.
 */
static int lazy_nesting;

/*
 * Validate that each event within the probe provider refers to the
 * right probe, and that the resulting name is not too long.
 */
static
bool check_event_provider(const struct lttng_ust_probe_desc *probe_desc)
{
	int i;

	for (i = 0; i < probe_desc->nr_events; i++) {
		const struct lttng_ust_event_desc *event_desc = probe_desc->event_desc[i];

		if (event_desc->probe_desc != probe_desc) {
			ERR("Error registering probe provider '%s'. Event '%s:%s' refers to the wrong provider descriptor.",
				probe_desc->provider_name, probe_desc->provider_name, event_desc->event_name);
			return false;	/* provider mismatch */
		}
		if (!lttng_ust_validate_event_name(event_desc)) {
			ERR("Error registering probe provider '%s'. Event '%s:%s' name is too long.",
				probe_desc->provider_name, probe_desc->provider_name, event_desc->event_name);
			return false;	/* provider mismatch */
		}
	}
	return true;
}

/*
 * Called under ust lock.
 */
static
void lttng_lazy_probe_register(struct lttng_ust_registered_probe *reg_probe)
{
	struct lttng_ust_registered_probe *iter;
	struct cds_list_head *probe_list;

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

	/*
	 * We sort the providers by struct lttng_ust_probe_desc pointer
	 * address.
	 */
	probe_list = &_probe_list;
	cds_list_for_each_entry_reverse(iter, probe_list, head) {
		BUG_ON(iter == reg_probe); /* Should never be in the list twice */
		if (iter < reg_probe) {
			/* We belong to the location right after iter. */
			cds_list_add(&reg_probe->head, &iter->head);
			goto probe_added;
		}
	}
	/* We should be added at the head of the list */
	cds_list_add(&reg_probe->head, probe_list);
probe_added:
	DBG("just registered probe %s containing %u events",
		reg_probe->desc->provider_name, reg_probe->desc->nr_events);
}

/*
 * Called under ust lock.
 */
static
void fixup_lazy_probes(void)
{
	struct lttng_ust_registered_probe *iter, *tmp;
	int ret;

	lazy_nesting++;
	cds_list_for_each_entry_safe(iter, tmp,
			&lazy_probe_init, lazy_init_head) {
		lttng_lazy_probe_register(iter);
		iter->lazy = 0;
		cds_list_del(&iter->lazy_init_head);
	}
	ret = lttng_fix_pending_events();
	assert(!ret);
	lazy_nesting--;
}

/*
 * Called under ust lock.
 */
struct cds_list_head *lttng_get_probe_list_head(void)
{
	if (!lazy_nesting && !cds_list_empty(&lazy_probe_init))
		fixup_lazy_probes();
	return &_probe_list;
}

static
int check_provider_version(const struct lttng_ust_probe_desc *desc)
{
	/*
	 * Check tracepoint provider version compatibility.
	 */
	if (desc->major <= LTTNG_UST_PROVIDER_MAJOR &&
			desc->major >= LTTNG_UST_PROVIDER_MAJOR_OLDEST_COMPATIBLE) {
		DBG("Provider \"%s\" accepted, version %u.%u is compatible "
			"with LTTng UST provider version %u.%u.",
			desc->provider_name, desc->major, desc->minor,
			LTTNG_UST_PROVIDER_MAJOR,
			LTTNG_UST_PROVIDER_MINOR);
		if (desc->major < LTTNG_UST_PROVIDER_MAJOR) {
			DBG("However, some LTTng UST features might not be "
				"available for this provider unless it is "
				"recompiled against a more recent LTTng UST.");
		}
		return 1;		/* accept */
	} else {
		ERR("Provider \"%s\" rejected, version %u.%u is incompatible "
			"with LTTng UST provider version %u.%u. Please upgrade "
			"LTTng UST.",
			desc->provider_name, desc->major, desc->minor,
			LTTNG_UST_PROVIDER_MAJOR,
			LTTNG_UST_PROVIDER_MINOR);
		return 0;		/* reject */
	}
}

struct lttng_ust_registered_probe *lttng_ust_probe_register(const struct lttng_ust_probe_desc *desc)
{
	struct lttng_ust_registered_probe *reg_probe = NULL;

	lttng_ust_alloc_tls();

	/*
	 * If version mismatch, don't register, but don't trigger assert
	 * on caller. The version check just prints an error.
	 */
	if (!check_provider_version(desc))
		return NULL;
	if (!check_event_provider(desc))
		return NULL;

	ust_lock_nocheck();

	reg_probe = zmalloc(sizeof(struct lttng_ust_registered_probe));
	if (!reg_probe)
		goto end;
	reg_probe->desc = desc;
	cds_list_add(&reg_probe->lazy_init_head, &lazy_probe_init);
	reg_probe->lazy = 1;

	DBG("adding probe %s containing %u events to lazy registration list",
		desc->provider_name, desc->nr_events);
	/*
	 * If there is at least one active session, we need to register
	 * the probe immediately, since we cannot delay event
	 * registration because they are needed ASAP.
	 */
	if (lttng_session_active())
		fixup_lazy_probes();

	lttng_fix_pending_event_notifiers();
end:
	ust_unlock();
	return reg_probe;
}

void lttng_ust_probe_unregister(struct lttng_ust_registered_probe *reg_probe)
{
	lttng_ust_alloc_tls();

	if (!reg_probe)
		return;
	if (!check_provider_version(reg_probe->desc))
		return;

	ust_lock_nocheck();
	if (!reg_probe->lazy)
		cds_list_del(&reg_probe->head);
	else
		cds_list_del(&reg_probe->lazy_init_head);

	lttng_probe_provider_unregister_events(reg_probe->desc);
	DBG("just unregistered probes of provider %s", reg_probe->desc->provider_name);
	ust_unlock();
	free(reg_probe);
}

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_ust_registered_probe *reg_probe;
	struct cds_list_head *probe_list;
	int i;

	probe_list = lttng_get_probe_list_head();
	CDS_INIT_LIST_HEAD(&list->head);
	cds_list_for_each_entry(reg_probe, probe_list, head) {
		const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;

		for (i = 0; i < probe_desc->nr_events; i++) {
			const struct lttng_ust_event_desc *event_desc =
				probe_desc->event_desc[i];
			struct tp_list_entry *list_entry;

			/* Skip event if name is too long. */
			if (!lttng_ust_validate_event_name(event_desc))
				continue;
			list_entry = zmalloc(sizeof(*list_entry));
			if (!list_entry)
				goto err_nomem;
			cds_list_add(&list_entry->head, &list->head);
			lttng_ust_format_event_name(event_desc, list_entry->tp.name);
			if (!event_desc->loglevel) {
				list_entry->tp.loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_DEFAULT;
			} else {
				list_entry->tp.loglevel = *(*event_desc->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_abi_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_ust_registered_probe *reg_probe;
	struct cds_list_head *probe_list;
	int i;

	probe_list = lttng_get_probe_list_head();
	CDS_INIT_LIST_HEAD(&list->head);
	cds_list_for_each_entry(reg_probe, probe_list, head) {
		const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;

		for (i = 0; i < probe_desc->nr_events; i++) {
			const struct lttng_ust_event_desc *event_desc =
				probe_desc->event_desc[i];
			int j;

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

				/* Skip event if name is too long. */
				if (!lttng_ust_validate_event_name(event_desc))
					continue;
				list_entry = zmalloc(sizeof(*list_entry));
				if (!list_entry)
					goto err_nomem;
				cds_list_add(&list_entry->head, &list->head);
				lttng_ust_format_event_name(event_desc, list_entry->field.event_name);
				list_entry->field.field_name[0] = '\0';
				list_entry->field.type = LTTNG_UST_ABI_FIELD_OTHER;
				if (!event_desc->loglevel) {
					list_entry->field.loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_DEFAULT;
				} else {
					list_entry->field.loglevel = *(*event_desc->loglevel);
				}
				list_entry->field.nowrite = 1;
			}

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

				/* Skip event if name is too long. */
				if (!lttng_ust_validate_event_name(event_desc))
					continue;
				list_entry = zmalloc(sizeof(*list_entry));
				if (!list_entry)
					goto err_nomem;
				cds_list_add(&list_entry->head, &list->head);
				lttng_ust_format_event_name(event_desc, list_entry->field.event_name);
				strncpy(list_entry->field.field_name,
					event_field->name,
					LTTNG_UST_ABI_SYM_NAME_LEN);
				list_entry->field.field_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
				switch (event_field->type->type) {
				case lttng_ust_type_integer:
					list_entry->field.type = LTTNG_UST_ABI_FIELD_INTEGER;
					break;
				case lttng_ust_type_string:
					list_entry->field.type = LTTNG_UST_ABI_FIELD_STRING;
					break;
				case lttng_ust_type_array:
					if (lttng_ust_get_type_array(event_field->type)->encoding == lttng_ust_string_encoding_none)
						list_entry->field.type = LTTNG_UST_ABI_FIELD_OTHER;
					else
						list_entry->field.type = LTTNG_UST_ABI_FIELD_STRING;
					break;
				case lttng_ust_type_sequence:
					if (lttng_ust_get_type_sequence(event_field->type)->encoding == lttng_ust_string_encoding_none)
						list_entry->field.type = LTTNG_UST_ABI_FIELD_OTHER;
					else
						list_entry->field.type = LTTNG_UST_ABI_FIELD_STRING;
					break;
				case lttng_ust_type_float:
					list_entry->field.type = LTTNG_UST_ABI_FIELD_FLOAT;
					break;
				case lttng_ust_type_enum:
					list_entry->field.type = LTTNG_UST_ABI_FIELD_ENUM;
					break;
				default:
					list_entry->field.type = LTTNG_UST_ABI_FIELD_OTHER;
				}
				if (!event_desc->loglevel) {
					list_entry->field.loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_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_abi_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
	1	/*
	2	* SPDX-License-Identifier: LGPL-2.1-only
	3	*
	4	* Copyright 2010-2012 (C) Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	5	*
	6	* Holds LTTng probes registry.
	7	*/
	8
	9	#define _LGPL_SOURCE
	10	#include <string.h>
	11	#include <errno.h>
	12	#include <urcu/list.h>
	13	#include <urcu/hlist.h>
	14	#include <lttng/ust-events.h>
	15	#include <lttng/tracepoint.h>
	16	#include "common/tracepoint.h"
	17	#include <assert.h>
	18	#include "common/macros.h"
	19	#include <ctype.h>
	20
	21	#include "lttng-tracer-core.h"
	22	#include "common/jhash.h"
	23	#include "lib/lttng-ust/events.h"
	24
	25	/*
	26	* probe list is protected by ust_lock()/ust_unlock().
	27	*/
	28	static CDS_LIST_HEAD(_probe_list);
	29
	30	/*
	31	* List of probes registered by not yet processed.
	32	*/
	33	static CDS_LIST_HEAD(lazy_probe_init);
	34
	35	/*
	36	* lazy_nesting counter ensures we don't trigger lazy probe registration
	37	* fixup while we are performing the fixup. It is protected by the ust
	38	* mutex.
	39	*/
	40	static int lazy_nesting;
	41
	42	/*
	43	* Validate that each event within the probe provider refers to the
	44	* right probe, and that the resulting name is not too long.
	45	*/
	46	static
	47	bool check_event_provider(const struct lttng_ust_probe_desc *probe_desc)
	48	{
	49	int i;
	50
	51	for (i = 0; i < probe_desc->nr_events; i++) {
	52	const struct lttng_ust_event_desc *event_desc = probe_desc->event_desc[i];
	53
	54	if (event_desc->probe_desc != probe_desc) {
	55	ERR("Error registering probe provider '%s'. Event '%s:%s' refers to the wrong provider descriptor.",
	56	probe_desc->provider_name, probe_desc->provider_name, event_desc->event_name);
	57	return false; /* provider mismatch */
	58	}
	59	if (!lttng_ust_validate_event_name(event_desc)) {
	60	ERR("Error registering probe provider '%s'. Event '%s:%s' name is too long.",
	61	probe_desc->provider_name, probe_desc->provider_name, event_desc->event_name);
	62	return false; /* provider mismatch */
	63	}
	64	}
	65	return true;
	66	}
	67
	68	/*
	69	* Called under ust lock.
	70	*/
	71	static
	72	void lttng_lazy_probe_register(struct lttng_ust_registered_probe *reg_probe)
	73	{
	74	struct lttng_ust_registered_probe *iter;
	75	struct cds_list_head *probe_list;
	76
	77	/*
	78	* The provider ensures there are no duplicate event names.
	79	* Duplicated LTTNG_UST_TRACEPOINT_EVENT event names would generate a
	80	* compile-time error due to duplicated symbol names.
	81	*/
	82
	83	/*
	84	* We sort the providers by struct lttng_ust_probe_desc pointer
	85	* address.
	86	*/
	87	probe_list = &_probe_list;
	88	cds_list_for_each_entry_reverse(iter, probe_list, head) {
	89	BUG_ON(iter == reg_probe); /* Should never be in the list twice */
	90	if (iter < reg_probe) {
	91	/* We belong to the location right after iter. */
	92	cds_list_add(&reg_probe->head, &iter->head);
	93	goto probe_added;
	94	}
	95	}
	96	/* We should be added at the head of the list */
	97	cds_list_add(&reg_probe->head, probe_list);
	98	probe_added:
	99	DBG("just registered probe %s containing %u events",
	100	reg_probe->desc->provider_name, reg_probe->desc->nr_events);
	101	}
	102
	103	/*
	104	* Called under ust lock.
	105	*/
	106	static
	107	void fixup_lazy_probes(void)
	108	{
	109	struct lttng_ust_registered_probe iter, tmp;
	110	int ret;
	111
	112	lazy_nesting++;
	113	cds_list_for_each_entry_safe(iter, tmp,
	114	&lazy_probe_init, lazy_init_head) {
	115	lttng_lazy_probe_register(iter);
	116	iter->lazy = 0;
	117	cds_list_del(&iter->lazy_init_head);
	118	}
	119	ret = lttng_fix_pending_events();
	120	assert(!ret);
	121	lazy_nesting--;
	122	}
	123
	124	/*
	125	* Called under ust lock.
	126	*/
	127	struct cds_list_head *lttng_get_probe_list_head(void)
	128	{
	129	if (!lazy_nesting && !cds_list_empty(&lazy_probe_init))
	130	fixup_lazy_probes();
	131	return &_probe_list;
	132	}
	133
	134	static
	135	int check_provider_version(const struct lttng_ust_probe_desc *desc)
	136	{
	137	/*
	138	* Check tracepoint provider version compatibility.
	139	*/
	140	if (desc->major <= LTTNG_UST_PROVIDER_MAJOR &&
	141	desc->major >= LTTNG_UST_PROVIDER_MAJOR_OLDEST_COMPATIBLE) {
	142	DBG("Provider \"%s\" accepted, version %u.%u is compatible "
	143	"with LTTng UST provider version %u.%u.",
	144	desc->provider_name, desc->major, desc->minor,
	145	LTTNG_UST_PROVIDER_MAJOR,
	146	LTTNG_UST_PROVIDER_MINOR);
	147	if (desc->major < LTTNG_UST_PROVIDER_MAJOR) {
	148	DBG("However, some LTTng UST features might not be "
	149	"available for this provider unless it is "
	150	"recompiled against a more recent LTTng UST.");
	151	}
	152	return 1; /* accept */
	153	} else {
	154	ERR("Provider \"%s\" rejected, version %u.%u is incompatible "
	155	"with LTTng UST provider version %u.%u. Please upgrade "
	156	"LTTng UST.",
	157	desc->provider_name, desc->major, desc->minor,
	158	LTTNG_UST_PROVIDER_MAJOR,
	159	LTTNG_UST_PROVIDER_MINOR);
	160	return 0; /* reject */
	161	}
	162	}
	163
	164	struct lttng_ust_registered_probe lttng_ust_probe_register(const struct lttng_ust_probe_desc desc)
	165	{
	166	struct lttng_ust_registered_probe *reg_probe = NULL;
	167
	168	lttng_ust_alloc_tls();
	169
	170	/*
	171	* If version mismatch, don't register, but don't trigger assert
	172	* on caller. The version check just prints an error.
	173	*/
	174	if (!check_provider_version(desc))
	175	return NULL;
	176	if (!check_event_provider(desc))
	177	return NULL;
	178
	179	ust_lock_nocheck();
	180
	181	reg_probe = zmalloc(sizeof(struct lttng_ust_registered_probe));
	182	if (!reg_probe)
	183	goto end;
	184	reg_probe->desc = desc;
	185	cds_list_add(&reg_probe->lazy_init_head, &lazy_probe_init);
	186	reg_probe->lazy = 1;
	187
	188	DBG("adding probe %s containing %u events to lazy registration list",
	189	desc->provider_name, desc->nr_events);
	190	/*
	191	* If there is at least one active session, we need to register
	192	* the probe immediately, since we cannot delay event
	193	* registration because they are needed ASAP.
	194	*/
	195	if (lttng_session_active())
	196	fixup_lazy_probes();
	197
	198	lttng_fix_pending_event_notifiers();
	199	end:
	200	ust_unlock();
	201	return reg_probe;
	202	}
	203
	204	void lttng_ust_probe_unregister(struct lttng_ust_registered_probe *reg_probe)
	205	{
	206	lttng_ust_alloc_tls();
	207
	208	if (!reg_probe)
	209	return;
	210	if (!check_provider_version(reg_probe->desc))
	211	return;
	212
	213	ust_lock_nocheck();
	214	if (!reg_probe->lazy)
	215	cds_list_del(&reg_probe->head);
	216	else
	217	cds_list_del(&reg_probe->lazy_init_head);
	218
	219	lttng_probe_provider_unregister_events(reg_probe->desc);
	220	DBG("just unregistered probes of provider %s", reg_probe->desc->provider_name);
	221	ust_unlock();
	222	free(reg_probe);
	223	}
	224
	225	void lttng_probes_prune_event_list(struct lttng_ust_tracepoint_list *list)
	226	{
	227	struct tp_list_entry list_entry, tmp;
	228
	229	cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) {
	230	cds_list_del(&list_entry->head);
	231	free(list_entry);
	232	}
	233	}
	234
	235	/*
	236	* called with UST lock held.
	237	*/
	238	int lttng_probes_get_event_list(struct lttng_ust_tracepoint_list *list)
	239	{
	240	struct lttng_ust_registered_probe *reg_probe;
	241	struct cds_list_head *probe_list;
	242	int i;
	243
	244	probe_list = lttng_get_probe_list_head();
	245	CDS_INIT_LIST_HEAD(&list->head);
	246	cds_list_for_each_entry(reg_probe, probe_list, head) {
	247	const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;
	248
	249	for (i = 0; i < probe_desc->nr_events; i++) {
	250	const struct lttng_ust_event_desc *event_desc =
	251	probe_desc->event_desc[i];
	252	struct tp_list_entry *list_entry;
	253
	254	/* Skip event if name is too long. */
	255	if (!lttng_ust_validate_event_name(event_desc))
	256	continue;
	257	list_entry = zmalloc(sizeof(*list_entry));
	258	if (!list_entry)
	259	goto err_nomem;
	260	cds_list_add(&list_entry->head, &list->head);
	261	lttng_ust_format_event_name(event_desc, list_entry->tp.name);
	262	if (!event_desc->loglevel) {
	263	list_entry->tp.loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_DEFAULT;
	264	} else {
	265	list_entry->tp.loglevel = (event_desc->loglevel);
	266	}
	267	}
	268	}
	269	if (cds_list_empty(&list->head))
	270	list->iter = NULL;
	271	else
	272	list->iter =
	273	cds_list_first_entry(&list->head, struct tp_list_entry, head);
	274	return 0;
	275
	276	err_nomem:
	277	lttng_probes_prune_event_list(list);
	278	return -ENOMEM;
	279	}
	280
	281	/*
	282	* Return current iteration position, advance internal iterator to next.
	283	* Return NULL if end of list.
	284	*/
	285	struct lttng_ust_abi_tracepoint_iter *
	286	lttng_ust_tracepoint_list_get_iter_next(struct lttng_ust_tracepoint_list *list)
	287	{
	288	struct tp_list_entry *entry;
	289
	290	if (!list->iter)
	291	return NULL;
	292	entry = list->iter;
	293	if (entry->head.next == &list->head)
	294	list->iter = NULL;
	295	else
	296	list->iter = cds_list_entry(entry->head.next,
	297	struct tp_list_entry, head);
	298	return &entry->tp;
	299	}
	300
	301	void lttng_probes_prune_field_list(struct lttng_ust_field_list *list)
	302	{
	303	struct tp_field_list_entry list_entry, tmp;
	304
	305	cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) {
	306	cds_list_del(&list_entry->head);
	307	free(list_entry);
	308	}
	309	}
	310
	311	/*
	312	* called with UST lock held.
	313	*/
	314	int lttng_probes_get_field_list(struct lttng_ust_field_list *list)
	315	{
	316	struct lttng_ust_registered_probe *reg_probe;
	317	struct cds_list_head *probe_list;
	318	int i;
	319
	320	probe_list = lttng_get_probe_list_head();
	321	CDS_INIT_LIST_HEAD(&list->head);
	322	cds_list_for_each_entry(reg_probe, probe_list, head) {
	323	const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;
	324
	325	for (i = 0; i < probe_desc->nr_events; i++) {
	326	const struct lttng_ust_event_desc *event_desc =
	327	probe_desc->event_desc[i];
	328	int j;
	329
	330	if (event_desc->tp_class->nr_fields == 0) {
	331	/* Events without fields. */
	332	struct tp_field_list_entry *list_entry;
	333
	334	/* Skip event if name is too long. */
	335	if (!lttng_ust_validate_event_name(event_desc))
	336	continue;
	337	list_entry = zmalloc(sizeof(*list_entry));
	338	if (!list_entry)
	339	goto err_nomem;
	340	cds_list_add(&list_entry->head, &list->head);
	341	lttng_ust_format_event_name(event_desc, list_entry->field.event_name);
	342	list_entry->field.field_name[0] = '\0';
	343	list_entry->field.type = LTTNG_UST_ABI_FIELD_OTHER;
	344	if (!event_desc->loglevel) {
	345	list_entry->field.loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_DEFAULT;
	346	} else {
	347	list_entry->field.loglevel = (event_desc->loglevel);
	348	}
	349	list_entry->field.nowrite = 1;
	350	}
	351
	352	for (j = 0; j < event_desc->tp_class->nr_fields; j++) {
	353	const struct lttng_ust_event_field *event_field =
	354	event_desc->tp_class->fields[j];
	355	struct tp_field_list_entry *list_entry;
	356
	357	/* Skip event if name is too long. */
	358	if (!lttng_ust_validate_event_name(event_desc))
	359	continue;
	360	list_entry = zmalloc(sizeof(*list_entry));
	361	if (!list_entry)
	362	goto err_nomem;
	363	cds_list_add(&list_entry->head, &list->head);
	364	lttng_ust_format_event_name(event_desc, list_entry->field.event_name);
	365	strncpy(list_entry->field.field_name,
	366	event_field->name,
	367	LTTNG_UST_ABI_SYM_NAME_LEN);
	368	list_entry->field.field_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
	369	switch (event_field->type->type) {
	370	case lttng_ust_type_integer:
	371	list_entry->field.type = LTTNG_UST_ABI_FIELD_INTEGER;
	372	break;
	373	case lttng_ust_type_string:
	374	list_entry->field.type = LTTNG_UST_ABI_FIELD_STRING;
	375	break;
	376	case lttng_ust_type_array:
	377	if (lttng_ust_get_type_array(event_field->type)->encoding == lttng_ust_string_encoding_none)
	378	list_entry->field.type = LTTNG_UST_ABI_FIELD_OTHER;
	379	else
	380	list_entry->field.type = LTTNG_UST_ABI_FIELD_STRING;
	381	break;
	382	case lttng_ust_type_sequence:
	383	if (lttng_ust_get_type_sequence(event_field->type)->encoding == lttng_ust_string_encoding_none)
	384	list_entry->field.type = LTTNG_UST_ABI_FIELD_OTHER;
	385	else
	386	list_entry->field.type = LTTNG_UST_ABI_FIELD_STRING;
	387	break;
	388	case lttng_ust_type_float:
	389	list_entry->field.type = LTTNG_UST_ABI_FIELD_FLOAT;
	390	break;
	391	case lttng_ust_type_enum:
	392	list_entry->field.type = LTTNG_UST_ABI_FIELD_ENUM;
	393	break;
	394	default:
	395	list_entry->field.type = LTTNG_UST_ABI_FIELD_OTHER;
	396	}
	397	if (!event_desc->loglevel) {
	398	list_entry->field.loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_DEFAULT;
	399	} else {
	400	list_entry->field.loglevel = (event_desc->loglevel);
	401	}
	402	list_entry->field.nowrite = event_field->nowrite;
	403	}
	404	}
	405	}
	406	if (cds_list_empty(&list->head))
	407	list->iter = NULL;
	408	else
	409	list->iter =
	410	cds_list_first_entry(&list->head,
	411	struct tp_field_list_entry, head);
	412	return 0;
	413
	414	err_nomem:
	415	lttng_probes_prune_field_list(list);
	416	return -ENOMEM;
	417	}
	418
	419	/*
	420	* Return current iteration position, advance internal iterator to next.
	421	* Return NULL if end of list.
	422	*/
	423	struct lttng_ust_abi_field_iter *
	424	lttng_ust_field_list_get_iter_next(struct lttng_ust_field_list *list)
	425	{
	426	struct tp_field_list_entry *entry;
	427
	428	if (!list->iter)
	429	return NULL;
	430	entry = list->iter;
	431	if (entry->head.next == &list->head)
	432	list->iter = NULL;
	433	else
	434	list->iter = cds_list_entry(entry->head.next,
	435	struct tp_field_list_entry, head);
	436	return &entry->field;
	437	}