/*
- * lttng-probes.c
+ * SPDX-License-Identifier: LGPL-2.1-only
*
- * 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.
+ * Copyright 2010-2012 (C) Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
- * 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
+ * Holds LTTng probes registry.
*/
+#define _LGPL_SOURCE
#include <string.h>
#include <errno.h>
#include <urcu/list.h>
#include "lttng-tracer-core.h"
#include "jhash.h"
#include "error.h"
+#include "ust-events-internal.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 CDS_LIST_HEAD(_probe_list);
-static
-const struct lttng_probe_desc *find_provider(const char *provider)
-{
- struct lttng_probe_desc *iter;
+/*
+ * List of probes registered by not yet processed.
+ */
+static CDS_LIST_HEAD(lazy_probe_init);
- cds_list_for_each_entry(iter, &probe_list, head) {
- if (!strcmp(iter->provider, provider))
- return iter;
- }
- return NULL;
-}
+/*
+ * 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;
+/*
+ * Called under ust lock.
+ */
static
-const struct lttng_event_desc *find_event(const char *name)
+int check_event_provider(struct lttng_probe_desc *desc)
{
- struct lttng_probe_desc *probe_desc;
int i;
+ size_t provider_name_len;
- cds_list_for_each_entry(probe_desc, &probe_list, head) {
- for (i = 0; i < probe_desc->nr_events; i++) {
- if (!strncmp(probe_desc->event_desc[i]->name, name,
- LTTNG_UST_SYM_NAME_LEN - 1))
- return probe_desc->event_desc[i];
- }
+ 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 NULL;
+ return 1;
}
-int lttng_probe_register(struct lttng_probe_desc *desc)
+/*
+ * Called under ust lock.
+ */
+static
+void lttng_lazy_probe_register(struct lttng_probe_desc *desc)
{
struct lttng_probe_desc *iter;
- int ret = 0;
- int i;
+ struct cds_list_head *probe_list;
- ust_lock();
- if (find_provider(desc->provider)) {
- ret = -EEXIST;
- goto end;
- }
/*
- * TODO: This is O(N^2). Turn into a hash table when probe registration
- * overhead becomes an issue.
+ * 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.
*/
- for (i = 0; i < desc->nr_events; i++) {
- if (find_event(desc->event_desc[i]->name)) {
- ret = -EEXIST;
- goto end;
- }
- }
/*
* We sort the providers by struct lttng_probe_desc pointer
* address.
*/
- cds_list_for_each_entry_reverse(iter, &probe_list, head) {
+ probe_list = &_probe_list;
+ 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. */
}
}
/* We should be added at the head of the list */
- cds_list_add(&desc->head, &probe_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)
+/*
+ * Called under ust lock.
+ */
+static
+void fixup_lazy_probes(void)
{
- return lttng_probe_register(desc);
+ struct lttng_probe_desc *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--;
}
-void lttng_probe_unregister(struct lttng_probe_desc *desc)
+/*
+ * Called under ust lock.
+ */
+struct cds_list_head *lttng_get_probe_list_head(void)
{
- ust_lock();
- cds_list_del(&desc->head);
- DBG("just unregistered probe %s", desc->provider);
- ust_unlock();
+ if (!lazy_nesting && !cds_list_empty(&lazy_probe_init))
+ fixup_lazy_probes();
+ return &_probe_list;
}
-/* Backward compatibility with UST 2.0 */
-void ltt_probe_unregister(struct lttng_probe_desc *desc)
+static
+int check_provider_version(struct lttng_probe_desc *desc)
{
- lttng_probe_unregister(desc);
+ /*
+ * Check tracepoint provider version compatibility.
+ */
+ if (desc->major <= LTTNG_UST_PROVIDER_MAJOR) {
+ DBG("Provider \"%s\" accepted, version %u.%u is compatible "
+ "with LTTng UST provider version %u.%u.",
+ desc->provider, 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, desc->major, desc->minor,
+ LTTNG_UST_PROVIDER_MAJOR,
+ LTTNG_UST_PROVIDER_MINOR);
+ return 0; /* reject */
+ }
}
-/*
- * called with UST lock held.
- */
-const struct lttng_event_desc *lttng_event_get(const char *name)
+
+int lttng_probe_register(struct lttng_probe_desc *desc)
{
- const struct lttng_event_desc *event;
+ int ret = 0;
- event = find_event(name);
- if (!event)
- return NULL;
- return event;
+ lttng_ust_fixup_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 0;
+
+ ust_lock_nocheck();
+
+ cds_list_add(&desc->lazy_init_head, &lazy_probe_init);
+ desc->lazy = 1;
+ DBG("adding probe %s containing %u events to lazy registration list",
+ desc->provider, 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();
+
+ ust_unlock();
+ return ret;
}
-void lttng_event_put(const struct lttng_event_desc *event)
+void lttng_probe_unregister(struct lttng_probe_desc *desc)
{
+ lttng_ust_fixup_tls();
+
+ if (!check_provider_version(desc))
+ return;
+
+ ust_lock_nocheck();
+ if (!desc->lazy)
+ cds_list_del(&desc->head);
+ else
+ cds_list_del(&desc->lazy_init_head);
+
+ lttng_probe_provider_unregister_events(desc);
+ DBG("just unregistered probes of provider %s", desc->provider);
+
+ ust_unlock();
}
void lttng_probes_prune_event_list(struct lttng_ust_tracepoint_list *list)
{
struct lttng_probe_desc *probe_desc;
int i;
+ struct cds_list_head *probe_list;
+ probe_list = lttng_get_probe_list_head();
CDS_INIT_LIST_HEAD(&list->head);
- cds_list_for_each_entry(probe_desc, &probe_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;
{
struct lttng_probe_desc *probe_desc;
int i;
+ struct cds_list_head *probe_list;
+ probe_list = lttng_get_probe_list_head();
CDS_INIT_LIST_HEAD(&list->head);
- cds_list_for_each_entry(probe_desc, &probe_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];
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)
+ if (event_field->type.u.legacy.array.elem_type.atype != atype_integer
+ || event_field->type.u.legacy.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_array_nestable:
+ if (event_field->type.u.array_nestable.elem_type->atype != atype_integer
+ || event_field->type.u.array_nestable.elem_type->u.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)
+ if (event_field->type.u.legacy.sequence.elem_type.atype != atype_integer
+ || event_field->type.u.legacy.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_sequence_nestable:
+ if (event_field->type.u.sequence_nestable.elem_type->atype != atype_integer
+ || event_field->type.u.sequence_nestable.elem_type->u.integer.encoding == lttng_encode_none)
list_entry->field.type = LTTNG_UST_FIELD_OTHER;
else
list_entry->field.type = LTTNG_UST_FIELD_STRING;
case atype_float:
list_entry->field.type = LTTNG_UST_FIELD_FLOAT;
break;
- case atype_enum:
+ case atype_enum: /* Fall-through */
+ case atype_enum_nestable:
list_entry->field.type = LTTNG_UST_FIELD_ENUM;
break;
default:
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