--- /dev/null
+/*
+ * lttng-events.c
+ *
+ * Holds LTTng per-session event registry.
+ *
+ * Copyright (C) 2010-2012 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
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <urcu/list.h>
+#include <urcu/hlist.h>
+#include <pthread.h>
+#include <errno.h>
+#include <sys/shm.h>
+#include <sys/ipc.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <inttypes.h>
+#include <time.h>
+#include <lttng/ust-endian.h>
+#include "clock.h"
+
+#include <urcu-bp.h>
+#include <urcu/compiler.h>
+#include <urcu/uatomic.h>
+#include <urcu/arch.h>
+
+#include <lttng/tracepoint.h>
+#include <lttng/ust-events.h>
+
+#include <usterr-signal-safe.h>
+#include <helper.h>
+#include "error.h"
+#include "compat.h"
+#include "lttng-ust-uuid.h"
+
+#include "tracepoint-internal.h"
+#include "lttng-tracer.h"
+#include "lttng-tracer-core.h"
+#include "wait.h"
+#include "../libringbuffer/shm.h"
+#include "jhash.h"
+
+/*
+ * The sessions mutex is the centralized mutex across UST tracing
+ * control and probe registration. All operations within this file are
+ * called by the communication thread, under ust_lock protection.
+ */
+static pthread_mutex_t sessions_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+void ust_lock(void)
+{
+ pthread_mutex_lock(&sessions_mutex);
+}
+
+void ust_unlock(void)
+{
+ pthread_mutex_unlock(&sessions_mutex);
+}
+
+static CDS_LIST_HEAD(sessions);
+
+/*
+ * Wildcard list, containing the active wildcards.
+ * Protected by ust lock.
+ */
+static CDS_LIST_HEAD(wildcard_list);
+
+/*
+ * Pending probes hash table, containing the registered ltt events for
+ * which tracepoint probes are still missing. Protected by the sessions
+ * mutex.
+ */
+#define PENDING_PROBE_HASH_BITS 6
+#define PENDING_PROBE_HASH_SIZE (1 << PENDING_PROBE_HASH_BITS)
+static struct cds_hlist_head pending_probe_table[PENDING_PROBE_HASH_SIZE];
+
+struct ust_pending_probe {
+ struct lttng_event *event;
+ struct cds_hlist_node node;
+ enum lttng_ust_loglevel_type loglevel_type;
+ int loglevel;
+ char name[];
+};
+
+static void _lttng_event_destroy(struct lttng_event *event);
+static void _lttng_wildcard_destroy(struct session_wildcard *sw);
+static void _lttng_channel_destroy(struct lttng_channel *chan);
+static int _lttng_event_unregister(struct lttng_event *event);
+static
+int _lttng_event_metadata_statedump(struct lttng_session *session,
+ struct lttng_channel *chan,
+ struct lttng_event *event);
+static
+int _lttng_session_metadata_statedump(struct lttng_session *session);
+
+int lttng_loglevel_match(const struct lttng_event_desc *desc,
+ enum lttng_ust_loglevel_type req_type,
+ int req_loglevel)
+{
+ int ev_loglevel;
+
+ if (req_type == LTTNG_UST_LOGLEVEL_ALL)
+ return 1;
+ if (!desc->loglevel)
+ ev_loglevel = TRACE_DEFAULT;
+ else
+ ev_loglevel = *(*desc->loglevel);
+ switch (req_type) {
+ case LTTNG_UST_LOGLEVEL_RANGE:
+ if (ev_loglevel <= req_loglevel || req_loglevel == -1)
+ return 1;
+ else
+ return 0;
+ case LTTNG_UST_LOGLEVEL_SINGLE:
+ if (ev_loglevel == req_loglevel || req_loglevel == -1)
+ return 1;
+ else
+ return 0;
+ case LTTNG_UST_LOGLEVEL_ALL:
+ default:
+ return 1;
+ }
+}
+
+/*
+ * Return wildcard for a given event name if the event name match the
+ * one of the wildcards.
+ * Must be called with ust lock held.
+ * Returns NULL if not present.
+ */
+static
+struct wildcard_entry *match_wildcard(const struct lttng_event_desc *desc)
+{
+ struct wildcard_entry *e;
+
+ cds_list_for_each_entry(e, &wildcard_list, list) {
+ /* If only contain '*' */
+ if (strlen(e->name) == 1)
+ goto possible_match;
+ /* Compare excluding final '*' */
+ if (!strncmp(desc->name, e->name, strlen(e->name) - 1))
+ goto possible_match;
+ continue; /* goto next, no match */
+ possible_match:
+ if (lttng_loglevel_match(desc,
+ e->loglevel_type,
+ e->loglevel)) {
+ return e;
+ }
+ /* no match, loop to next */
+ }
+ return NULL;
+}
+
+/*
+ * called at event creation if probe is missing.
+ * called with session mutex held.
+ */
+static
+int add_pending_probe(struct lttng_event *event, const char *name,
+ enum lttng_ust_loglevel_type loglevel_type,
+ int loglevel)
+{
+ struct cds_hlist_head *head;
+ struct ust_pending_probe *e;
+ size_t name_len = strlen(name) + 1;
+ uint32_t hash;
+
+ if (name_len > LTTNG_UST_SYM_NAME_LEN) {
+ WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN);
+ name_len = LTTNG_UST_SYM_NAME_LEN;
+ }
+ hash = jhash(name, name_len - 1, 0);
+ head = &pending_probe_table[hash & (PENDING_PROBE_HASH_SIZE - 1)];
+ e = zmalloc(sizeof(struct ust_pending_probe) + name_len);
+ if (!e)
+ return -ENOMEM;
+ memcpy(&e->name[0], name, name_len);
+ e->name[name_len - 1] = '\0';
+ e->loglevel_type = loglevel_type;
+ e->loglevel = loglevel;
+ cds_hlist_add_head(&e->node, head);
+ e->event = event;
+ event->pending_probe = e;
+ return 0;
+}
+
+/*
+ * remove a pending probe. called when at event teardown and when an
+ * event is fixed (probe is loaded).
+ * called with session mutex held.
+ */
+static
+void remove_pending_probe(struct ust_pending_probe *e)
+{
+ if (!e)
+ return;
+ cds_hlist_del(&e->node);
+ free(e);
+}
+
+/*
+ * Called at library load: connect the probe on the events pending on
+ * probe load.
+ * called with session mutex held.
+ */
+int pending_probe_fix_events(const struct lttng_event_desc *desc)
+{
+ struct cds_hlist_head *head;
+ struct cds_hlist_node *node, *p;
+ struct ust_pending_probe *e;
+ const char *name = desc->name;
+ int ret = 0;
+ struct lttng_ust_event event_param;
+ size_t name_len = strlen(name) + 1;
+ uint32_t hash;
+
+ /* Wildcard */
+ {
+ struct wildcard_entry *wildcard;
+
+ //FIXME: should iterate on all match for filter.
+ //FIXME: should re-use pending event if present rather
+ //than create duplicate.
+ wildcard = match_wildcard(desc);
+ if (strcmp(desc->name, "lttng_ust:metadata") && wildcard) {
+ struct session_wildcard *sw;
+
+ cds_list_for_each_entry(sw, &wildcard->session_list,
+ session_list) {
+ struct lttng_event *ev;
+ int ret;
+
+ memcpy(&event_param, &sw->event_param,
+ sizeof(event_param));
+ strncpy(event_param.name,
+ desc->name,
+ sizeof(event_param.name));
+ event_param.name[sizeof(event_param.name) - 1] = '\0';
+ /* create event */
+ ret = lttng_event_create(sw->chan,
+ &event_param, &ev);
+ if (ret) {
+ DBG("Error creating event");
+ continue;
+ }
+ cds_list_add(&ev->wildcard_list,
+ &sw->events);
+ lttng_filter_event_link_wildcard_bytecode(ev,
+ sw);
+ }
+ }
+ }
+
+ if (name_len > LTTNG_UST_SYM_NAME_LEN) {
+ WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN);
+ name_len = LTTNG_UST_SYM_NAME_LEN;
+ }
+ hash = jhash(name, name_len - 1, 0);
+ head = &pending_probe_table[hash & (PENDING_PROBE_HASH_SIZE - 1)];
+ cds_hlist_for_each_entry_safe(e, node, p, head, node) {
+ struct lttng_event *event;
+ struct lttng_channel *chan;
+
+ if (!lttng_loglevel_match(desc,
+ e->loglevel_type,
+ e->loglevel)) {
+ continue;
+ }
+ if (strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) {
+ continue;
+ }
+ /* TODO: wildcard same as pending event: duplicate */
+ /* TODO: Should apply filter though */
+ event = e->event;
+ chan = event->chan;
+ assert(!event->desc);
+ event->desc = desc;
+ event->pending_probe = NULL;
+ remove_pending_probe(e);
+ ret |= __tracepoint_probe_register(name,
+ event->desc->probe_callback,
+ event, event->desc->signature);
+ if (ret)
+ continue;
+ event->id = chan->free_event_id++;
+ ret |= _lttng_event_metadata_statedump(chan->session, chan,
+ event);
+ lttng_filter_event_link_bytecode(event);
+ }
+ return ret;
+}
+
+void synchronize_trace(void)
+{
+ synchronize_rcu();
+}
+
+struct lttng_session *lttng_session_create(void)
+{
+ struct lttng_session *session;
+ int ret;
+
+ session = zmalloc(sizeof(struct lttng_session));
+ if (!session)
+ return NULL;
+ CDS_INIT_LIST_HEAD(&session->chan);
+ CDS_INIT_LIST_HEAD(&session->events);
+ CDS_INIT_LIST_HEAD(&session->wildcards);
+ ret = lttng_ust_uuid_generate(session->uuid);
+ if (ret != 0) {
+ session->uuid[0] = '\0';
+ }
+ cds_list_add(&session->list, &sessions);
+ return session;
+}
+
+void lttng_session_destroy(struct lttng_session *session)
+{
+ struct lttng_channel *chan, *tmpchan;
+ struct lttng_event *event, *tmpevent;
+ struct session_wildcard *wildcard, *tmpwildcard;
+ int ret;
+
+ CMM_ACCESS_ONCE(session->active) = 0;
+ cds_list_for_each_entry(event, &session->events, list) {
+ ret = _lttng_event_unregister(event);
+ WARN_ON(ret);
+ }
+ synchronize_trace(); /* Wait for in-flight events to complete */
+ cds_list_for_each_entry_safe(wildcard, tmpwildcard, &session->wildcards, list)
+ _lttng_wildcard_destroy(wildcard);
+ cds_list_for_each_entry_safe(event, tmpevent, &session->events, list)
+ _lttng_event_destroy(event);
+ cds_list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
+ _lttng_channel_destroy(chan);
+ cds_list_del(&session->list);
+ free(session);
+}
+
+int lttng_session_enable(struct lttng_session *session)
+{
+ int ret = 0;
+ struct lttng_channel *chan;
+
+ if (session->active) {
+ ret = -EBUSY;
+ goto end;
+ }
+
+ /*
+ * Snapshot the number of events per channel to know the type of header
+ * we need to use.
+ */
+ cds_list_for_each_entry(chan, &session->chan, list) {
+ if (chan->header_type)
+ continue; /* don't change it if session stop/restart */
+ if (chan->free_event_id < 31)
+ chan->header_type = 1; /* compact */
+ else
+ chan->header_type = 2; /* large */
+ }
+
+ CMM_ACCESS_ONCE(session->active) = 1;
+ CMM_ACCESS_ONCE(session->been_active) = 1;
+ ret = _lttng_session_metadata_statedump(session);
+ if (ret)
+ CMM_ACCESS_ONCE(session->active) = 0;
+end:
+ return ret;
+}
+
+int lttng_session_disable(struct lttng_session *session)
+{
+ int ret = 0;
+
+ if (!session->active) {
+ ret = -EBUSY;
+ goto end;
+ }
+ CMM_ACCESS_ONCE(session->active) = 0;
+end:
+ return ret;
+}
+
+int lttng_channel_enable(struct lttng_channel *channel)
+{
+ int old;
+
+ if (channel == channel->session->metadata)
+ return -EPERM;
+ old = uatomic_xchg(&channel->enabled, 1);
+ if (old)
+ return -EEXIST;
+ return 0;
+}
+
+int lttng_channel_disable(struct lttng_channel *channel)
+{
+ int old;
+
+ if (channel == channel->session->metadata)
+ return -EPERM;
+ old = uatomic_xchg(&channel->enabled, 0);
+ if (!old)
+ return -EEXIST;
+ return 0;
+}
+
+int lttng_event_enable(struct lttng_event *event)
+{
+ int old;
+
+ if (event->chan == event->chan->session->metadata)
+ return -EPERM;
+ old = uatomic_xchg(&event->enabled, 1);
+ if (old)
+ return -EEXIST;
+ return 0;
+}
+
+int lttng_event_disable(struct lttng_event *event)
+{
+ int old;
+
+ if (event->chan == event->chan->session->metadata)
+ return -EPERM;
+ old = uatomic_xchg(&event->enabled, 0);
+ if (!old)
+ return -EEXIST;
+ return 0;
+}
+
+struct lttng_channel *lttng_channel_create(struct lttng_session *session,
+ const char *transport_name,
+ void *buf_addr,
+ size_t subbuf_size, size_t num_subbuf,
+ unsigned int switch_timer_interval,
+ unsigned int read_timer_interval,
+ int **shm_fd, int **wait_fd,
+ uint64_t **memory_map_size,
+ struct lttng_channel *chan_priv_init)
+{
+ struct lttng_channel *chan = NULL;
+ struct lttng_transport *transport;
+
+ if (session->been_active)
+ goto active; /* Refuse to add channel to active session */
+ transport = lttng_transport_find(transport_name);
+ if (!transport) {
+ DBG("LTTng transport %s not found\n",
+ transport_name);
+ goto notransport;
+ }
+ chan_priv_init->id = session->free_chan_id++;
+ chan_priv_init->session = session;
+ /*
+ * Note: the channel creation op already writes into the packet
+ * headers. Therefore the "chan" information used as input
+ * should be already accessible.
+ */
+ chan = transport->ops.channel_create(transport_name, buf_addr,
+ subbuf_size, num_subbuf, switch_timer_interval,
+ read_timer_interval, shm_fd, wait_fd,
+ memory_map_size, chan_priv_init);
+ if (!chan)
+ goto create_error;
+ chan->enabled = 1;
+ chan->ops = &transport->ops;
+ cds_list_add(&chan->list, &session->chan);
+ return chan;
+
+create_error:
+notransport:
+active:
+ return NULL;
+}
+
+/*
+ * Only used internally at session destruction.
+ */
+static
+void _lttng_channel_destroy(struct lttng_channel *chan)
+{
+ cds_list_del(&chan->list);
+ lttng_destroy_context(chan->ctx);
+ chan->ops->channel_destroy(chan);
+}
+
+/*
+ * Supports event creation while tracing session is active.
+ */
+int lttng_event_create(struct lttng_channel *chan,
+ struct lttng_ust_event *event_param,
+ struct lttng_event **_event)
+{
+ const struct lttng_event_desc *desc = NULL; /* silence gcc */
+ struct lttng_event *event;
+ int ret = 0;
+
+ if (chan->used_event_id == -1U) {
+ ret = -ENOMEM;
+ goto full;
+ }
+ //FIXME: re-use event if already registered by wildcard or
+ //if we have a pending probe.... (CHECK)
+ /*
+ * This is O(n^2) (for each event, the loop is called at event
+ * creation). Might require a hash if we have lots of events.
+ */
+ cds_list_for_each_entry(event, &chan->session->events, list) {
+ if (event->desc && !strncmp(event->desc->name,
+ event_param->name,
+ LTTNG_UST_SYM_NAME_LEN - 1)) {
+ ret = -EEXIST;
+ goto exist;
+ }
+ }
+
+ /*
+ * Check if loglevel match. Refuse to connect event if not.
+ */
+ if (event_param->instrumentation == LTTNG_UST_TRACEPOINT) {
+ desc = lttng_event_get(event_param->name);
+ if (desc) {
+ if (!lttng_loglevel_match(desc,
+ event_param->loglevel_type,
+ event_param->loglevel)) {
+ ret = -EPERM;
+ goto no_loglevel_match;
+ }
+ }
+ /*
+ * If descriptor is not there, it will be added to
+ * pending probes.
+ */
+ }
+ event = zmalloc(sizeof(struct lttng_event));
+ if (!event) {
+ ret = -ENOMEM;
+ goto cache_error;
+ }
+ event->chan = chan;
+ /*
+ * used_event_id counts the maximum number of event IDs that can
+ * register if all probes register.
+ */
+ chan->used_event_id++;
+ event->enabled = 1;
+ CDS_INIT_LIST_HEAD(&event->filter_bytecode);
+ CDS_INIT_LIST_HEAD(&event->bytecode_runtime);
+ event->instrumentation = event_param->instrumentation;
+ /* Populate lttng_event structure before tracepoint registration. */
+ cmm_smp_wmb();
+ switch (event_param->instrumentation) {
+ case LTTNG_UST_TRACEPOINT:
+ event->desc = desc;
+ if (event->desc) {
+ ret = __tracepoint_probe_register(event_param->name,
+ event->desc->probe_callback,
+ event, event->desc->signature);
+ if (ret)
+ goto register_error;
+ event->id = chan->free_event_id++;
+ } else {
+ /*
+ * If the probe is not present, event->desc stays NULL,
+ * waiting for the probe to register, and the event->id
+ * stays unallocated.
+ */
+ ret = add_pending_probe(event, event_param->name,
+ event_param->loglevel_type,
+ event_param->loglevel);
+ if (ret)
+ goto add_pending_error;
+ }
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+ if (event->desc) {
+ ret = _lttng_event_metadata_statedump(chan->session, chan, event);
+ if (ret)
+ goto statedump_error;
+ }
+ cds_list_add(&event->list, &chan->session->events);
+ *_event = event;
+ return 0;
+
+statedump_error:
+ if (event->desc) {
+ WARN_ON_ONCE(__tracepoint_probe_unregister(event_param->name,
+ event->desc->probe_callback,
+ event));
+ lttng_event_put(event->desc);
+ }
+add_pending_error:
+register_error:
+ free(event);
+cache_error:
+no_loglevel_match:
+exist:
+full:
+ return ret;
+}
+
+/*
+ * Only used internally at session destruction.
+ */
+int _lttng_event_unregister(struct lttng_event *event)
+{
+ int ret = -EINVAL;
+
+ switch (event->instrumentation) {
+ case LTTNG_UST_TRACEPOINT:
+ if (event->desc) {
+ ret = __tracepoint_probe_unregister(event->desc->name,
+ event->desc->probe_callback,
+ event);
+ if (ret)
+ return ret;
+ } else {
+ remove_pending_probe(event->pending_probe);
+ ret = 0;
+ }
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+ return ret;
+}
+
+/*
+ * Only used internally at session destruction.
+ */
+static
+void _lttng_event_destroy(struct lttng_event *event)
+{
+ switch (event->instrumentation) {
+ case LTTNG_UST_TRACEPOINT:
+ if (event->desc) {
+ lttng_event_put(event->desc);
+ }
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+ cds_list_del(&event->list);
+ lttng_destroy_context(event->ctx);
+ lttng_free_event_filter_runtime(event);
+ lttng_free_event_filter_bytecode(event);
+ free(event);
+}
+
+/*
+ * We have exclusive access to our metadata buffer (protected by the
+ * ust_lock), so we can do racy operations such as looking for
+ * remaining space left in packet and write, since mutual exclusion
+ * protects us from concurrent writes.
+ */
+int lttng_metadata_printf(struct lttng_session *session,
+ const char *fmt, ...)
+{
+ struct lttng_ust_lib_ring_buffer_ctx ctx;
+ struct lttng_channel *chan = session->metadata;
+ char *str = NULL;
+ int ret = 0, waitret;
+ size_t len, reserve_len, pos;
+ va_list ap;
+
+ WARN_ON_ONCE(!CMM_ACCESS_ONCE(session->active));
+
+ va_start(ap, fmt);
+ ret = vasprintf(&str, fmt, ap);
+ va_end(ap);
+ if (ret < 0)
+ return -ENOMEM;
+
+ len = strlen(str);
+ pos = 0;
+
+ for (pos = 0; pos < len; pos += reserve_len) {
+ reserve_len = min_t(size_t,
+ chan->ops->packet_avail_size(chan->chan, chan->handle),
+ len - pos);
+ lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, reserve_len,
+ sizeof(char), -1, chan->handle);
+ /*
+ * We don't care about metadata buffer's records lost
+ * count, because we always retry here. Report error if
+ * we need to bail out after timeout or being
+ * interrupted.
+ */
+ waitret = wait_cond_interruptible_timeout(
+ ({
+ ret = chan->ops->event_reserve(&ctx, 0);
+ ret != -ENOBUFS || !ret;
+ }),
+ LTTNG_METADATA_TIMEOUT_MSEC);
+ if (waitret == -ETIMEDOUT || waitret == -EINTR || ret) {
+ DBG("LTTng: Failure to write metadata to buffers (%s)\n",
+ waitret == -EINTR ? "interrupted" :
+ (ret == -ENOBUFS ? "timeout" : "I/O error"));
+ if (waitret == -EINTR)
+ ret = waitret;
+ goto end;
+ }
+ chan->ops->event_write(&ctx, &str[pos], reserve_len);
+ chan->ops->event_commit(&ctx);
+ }
+end:
+ free(str);
+ return ret;
+}
+
+static
+int _lttng_field_statedump(struct lttng_session *session,
+ const struct lttng_event_field *field)
+{
+ int ret = 0;
+
+ if (field->nowrite)
+ return 0;
+
+ switch (field->type.atype) {
+ case atype_integer:
+ ret = lttng_metadata_printf(session,
+ " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s;\n",
+ field->type.u.basic.integer.size,
+ field->type.u.basic.integer.alignment,
+ field->type.u.basic.integer.signedness,
+ (field->type.u.basic.integer.encoding == lttng_encode_none)
+ ? "none"
+ : (field->type.u.basic.integer.encoding == lttng_encode_UTF8)
+ ? "UTF8"
+ : "ASCII",
+ field->type.u.basic.integer.base,
+#if (BYTE_ORDER == BIG_ENDIAN)
+ field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
+#else
+ field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
+#endif
+ field->name);
+ break;
+ case atype_float:
+ ret = lttng_metadata_printf(session,
+ " floating_point { exp_dig = %u; mant_dig = %u; align = %u;%s } _%s;\n",
+ field->type.u.basic._float.exp_dig,
+ field->type.u.basic._float.mant_dig,
+ field->type.u.basic._float.alignment,
+#if (BYTE_ORDER == BIG_ENDIAN)
+ field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
+#else
+ field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
+#endif
+ field->name);
+ break;
+ case atype_enum:
+ ret = lttng_metadata_printf(session,
+ " %s %s;\n",
+ field->type.u.basic.enumeration.name,
+ field->name);
+ break;
+ case atype_array:
+ {
+ const struct lttng_basic_type *elem_type;
+
+ elem_type = &field->type.u.array.elem_type;
+ ret = lttng_metadata_printf(session,
+ " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
+ elem_type->u.basic.integer.size,
+ elem_type->u.basic.integer.alignment,
+ elem_type->u.basic.integer.signedness,
+ (elem_type->u.basic.integer.encoding == lttng_encode_none)
+ ? "none"
+ : (elem_type->u.basic.integer.encoding == lttng_encode_UTF8)
+ ? "UTF8"
+ : "ASCII",
+ elem_type->u.basic.integer.base,
+#if (BYTE_ORDER == BIG_ENDIAN)
+ elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
+#else
+ elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
+#endif
+ field->name, field->type.u.array.length);
+ break;
+ }
+ case atype_sequence:
+ {
+ const struct lttng_basic_type *elem_type;
+ const struct lttng_basic_type *length_type;
+
+ elem_type = &field->type.u.sequence.elem_type;
+ length_type = &field->type.u.sequence.length_type;
+ ret = lttng_metadata_printf(session,
+ " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
+ length_type->u.basic.integer.size,
+ (unsigned int) length_type->u.basic.integer.alignment,
+ length_type->u.basic.integer.signedness,
+ (length_type->u.basic.integer.encoding == lttng_encode_none)
+ ? "none"
+ : ((length_type->u.basic.integer.encoding == lttng_encode_UTF8)
+ ? "UTF8"
+ : "ASCII"),
+ length_type->u.basic.integer.base,
+#if (BYTE_ORDER == BIG_ENDIAN)
+ length_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
+#else
+ length_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
+#endif
+ field->name);
+ if (ret)
+ return ret;
+
+ ret = lttng_metadata_printf(session,
+ " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
+ elem_type->u.basic.integer.size,
+ (unsigned int) elem_type->u.basic.integer.alignment,
+ elem_type->u.basic.integer.signedness,
+ (elem_type->u.basic.integer.encoding == lttng_encode_none)
+ ? "none"
+ : ((elem_type->u.basic.integer.encoding == lttng_encode_UTF8)
+ ? "UTF8"
+ : "ASCII"),
+ elem_type->u.basic.integer.base,
+#if (BYTE_ORDER == BIG_ENDIAN)
+ elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
+#else
+ elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
+#endif
+ field->name,
+ field->name);
+ break;
+ }
+
+ case atype_string:
+ /* Default encoding is UTF8 */
+ ret = lttng_metadata_printf(session,
+ " string%s _%s;\n",
+ field->type.u.basic.string.encoding == lttng_encode_ASCII ?
+ " { encoding = ASCII; }" : "",
+ field->name);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return -EINVAL;
+ }
+ return ret;
+}
+
+static
+int _lttng_context_metadata_statedump(struct lttng_session *session,
+ struct lttng_ctx *ctx)
+{
+ int ret = 0;
+ int i;
+
+ if (!ctx)
+ return 0;
+ for (i = 0; i < ctx->nr_fields; i++) {
+ const struct lttng_ctx_field *field = &ctx->fields[i];
+
+ ret = _lttng_field_statedump(session, &field->event_field);
+ if (ret)
+ return ret;
+ }
+ return ret;
+}
+
+static
+int _lttng_fields_metadata_statedump(struct lttng_session *session,
+ struct lttng_event *event)
+{
+ const struct lttng_event_desc *desc = event->desc;
+ int ret = 0;
+ int i;
+
+ for (i = 0; i < desc->nr_fields; i++) {
+ const struct lttng_event_field *field = &desc->fields[i];
+
+ ret = _lttng_field_statedump(session, field);
+ if (ret)
+ return ret;
+ }
+ return ret;
+}
+
+static
+int _lttng_event_metadata_statedump(struct lttng_session *session,
+ struct lttng_channel *chan,
+ struct lttng_event *event)
+{
+ int ret = 0;
+ int loglevel = TRACE_DEFAULT;
+
+ if (event->metadata_dumped || !CMM_ACCESS_ONCE(session->active))
+ return 0;
+ if (chan == session->metadata)
+ return 0;
+ /*
+ * Don't print events for which probe load is pending.
+ */
+ if (!event->desc)
+ return 0;
+
+ ret = lttng_metadata_printf(session,
+ "event {\n"
+ " name = \"%s\";\n"
+ " id = %u;\n"
+ " stream_id = %u;\n",
+ event->desc->name,
+ event->id,
+ event->chan->id);
+ if (ret)
+ goto end;
+
+ if (event->desc->loglevel)
+ loglevel = *(*event->desc->loglevel);
+
+ ret = lttng_metadata_printf(session,
+ " loglevel = %d;\n",
+ loglevel);
+ if (ret)
+ goto end;
+
+ if (event->desc->u.ext.model_emf_uri) {
+ ret = lttng_metadata_printf(session,
+ " model.emf.uri = \"%s\";\n",
+ *(event->desc->u.ext.model_emf_uri));
+ if (ret)
+ goto end;
+ }
+
+ if (event->ctx) {
+ ret = lttng_metadata_printf(session,
+ " context := struct {\n");
+ if (ret)
+ goto end;
+ }
+ ret = _lttng_context_metadata_statedump(session, event->ctx);
+ if (ret)
+ goto end;
+ if (event->ctx) {
+ ret = lttng_metadata_printf(session,
+ " };\n");
+ if (ret)
+ goto end;
+ }
+
+ ret = lttng_metadata_printf(session,
+ " fields := struct {\n"
+ );
+ if (ret)
+ goto end;
+
+ ret = _lttng_fields_metadata_statedump(session, event);
+ if (ret)
+ goto end;
+
+ /*
+ * LTTng space reservation can only reserve multiples of the
+ * byte size.
+ */
+ ret = lttng_metadata_printf(session,
+ " };\n"
+ "};\n\n");
+ if (ret)
+ goto end;
+
+ event->metadata_dumped = 1;
+end:
+ return ret;
+
+}
+
+static
+int _lttng_channel_metadata_statedump(struct lttng_session *session,
+ struct lttng_channel *chan)
+{
+ int ret = 0;
+
+ if (chan->metadata_dumped || !CMM_ACCESS_ONCE(session->active))
+ return 0;
+ if (chan == session->metadata)
+ return 0;
+
+ WARN_ON_ONCE(!chan->header_type);
+ ret = lttng_metadata_printf(session,
+ "stream {\n"
+ " id = %u;\n"
+ " event.header := %s;\n"
+ " packet.context := struct packet_context;\n",
+ chan->id,
+ chan->header_type == 1 ? "struct event_header_compact" :
+ "struct event_header_large");
+ if (ret)
+ goto end;
+
+ if (chan->ctx) {
+ ret = lttng_metadata_printf(session,
+ " event.context := struct {\n");
+ if (ret)
+ goto end;
+ }
+ ret = _lttng_context_metadata_statedump(session, chan->ctx);
+ if (ret)
+ goto end;
+ if (chan->ctx) {
+ ret = lttng_metadata_printf(session,
+ " };\n");
+ if (ret)
+ goto end;
+ }
+
+ ret = lttng_metadata_printf(session,
+ "};\n\n");
+
+ chan->metadata_dumped = 1;
+end:
+ return ret;
+}
+
+static
+int _lttng_stream_packet_context_declare(struct lttng_session *session)
+{
+ return lttng_metadata_printf(session,
+ "struct packet_context {\n"
+ " uint64_clock_monotonic_t timestamp_begin;\n"
+ " uint64_clock_monotonic_t timestamp_end;\n"
+ " uint64_t content_size;\n"
+ " uint64_t packet_size;\n"
+ " unsigned long events_discarded;\n"
+ " uint32_t cpu_id;\n"
+ "};\n\n"
+ );
+}
+
+/*
+ * Compact header:
+ * id: range: 0 - 30.
+ * id 31 is reserved to indicate an extended header.
+ *
+ * Large header:
+ * id: range: 0 - 65534.
+ * id 65535 is reserved to indicate an extended header.
+ */
+static
+int _lttng_event_header_declare(struct lttng_session *session)
+{
+ return lttng_metadata_printf(session,
+ "struct event_header_compact {\n"
+ " enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
+ " variant <id> {\n"
+ " struct {\n"
+ " uint27_clock_monotonic_t timestamp;\n"
+ " } compact;\n"
+ " struct {\n"
+ " uint32_t id;\n"
+ " uint64_clock_monotonic_t timestamp;\n"
+ " } extended;\n"
+ " } v;\n"
+ "} align(%u);\n"
+ "\n"
+ "struct event_header_large {\n"
+ " enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
+ " variant <id> {\n"
+ " struct {\n"
+ " uint32_clock_monotonic_t timestamp;\n"
+ " } compact;\n"
+ " struct {\n"
+ " uint32_t id;\n"
+ " uint64_clock_monotonic_t timestamp;\n"
+ " } extended;\n"
+ " } v;\n"
+ "} align(%u);\n\n",
+ lttng_alignof(uint32_t) * CHAR_BIT,
+ lttng_alignof(uint16_t) * CHAR_BIT
+ );
+}
+
+/*
+ * Approximation of NTP time of day to clock monotonic correlation,
+ * taken at start of trace.
+ * Yes, this is only an approximation. Yes, we can (and will) do better
+ * in future versions.
+ */
+static
+uint64_t measure_clock_offset(void)
+{
+ uint64_t offset, monotonic[2], realtime;
+ struct timespec rts = { 0, 0 };
+ int ret;
+
+ monotonic[0] = trace_clock_read64();
+ ret = clock_gettime(CLOCK_REALTIME, &rts);
+ if (ret < 0)
+ return 0;
+ monotonic[1] = trace_clock_read64();
+ offset = (monotonic[0] + monotonic[1]) >> 1;
+ realtime = (uint64_t) rts.tv_sec * 1000000000ULL;
+ realtime += rts.tv_nsec;
+ offset = realtime - offset;
+ return offset;
+}
+
+/*
+ * Output metadata into this session's metadata buffers.
+ */
+static
+int _lttng_session_metadata_statedump(struct lttng_session *session)
+{
+ unsigned char *uuid_c = session->uuid;
+ char uuid_s[LTTNG_UST_UUID_STR_LEN],
+ clock_uuid_s[LTTNG_UST_UUID_STR_LEN];
+ struct lttng_channel *chan;
+ struct lttng_event *event;
+ int ret = 0;
+ char procname[LTTNG_UST_PROCNAME_LEN] = "";
+ char hostname[HOST_NAME_MAX];
+
+ if (!CMM_ACCESS_ONCE(session->active))
+ return 0;
+ if (session->metadata_dumped)
+ goto skip_session;
+ if (!session->metadata) {
+ DBG("LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n");
+ return -EPERM;
+ }
+
+ snprintf(uuid_s, sizeof(uuid_s),
+ "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+ uuid_c[0], uuid_c[1], uuid_c[2], uuid_c[3],
+ uuid_c[4], uuid_c[5], uuid_c[6], uuid_c[7],
+ uuid_c[8], uuid_c[9], uuid_c[10], uuid_c[11],
+ uuid_c[12], uuid_c[13], uuid_c[14], uuid_c[15]);
+
+ ret = lttng_metadata_printf(session,
+ "typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
+ "typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
+ "typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
+ "typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
+ "typealias integer { size = %u; align = %u; signed = false; } := unsigned long;\n"
+ "typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
+ "typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
+ "\n"
+ "trace {\n"
+ " major = %u;\n"
+ " minor = %u;\n"
+ " uuid = \"%s\";\n"
+ " byte_order = %s;\n"
+ " packet.header := struct {\n"
+ " uint32_t magic;\n"
+ " uint8_t uuid[16];\n"
+ " uint32_t stream_id;\n"
+ " };\n"
+ "};\n\n",
+ lttng_alignof(uint8_t) * CHAR_BIT,
+ lttng_alignof(uint16_t) * CHAR_BIT,
+ lttng_alignof(uint32_t) * CHAR_BIT,
+ lttng_alignof(uint64_t) * CHAR_BIT,
+ sizeof(unsigned long) * CHAR_BIT,
+ lttng_alignof(unsigned long) * CHAR_BIT,
+ CTF_SPEC_MAJOR,
+ CTF_SPEC_MINOR,
+ uuid_s,
+#if (BYTE_ORDER == BIG_ENDIAN)
+ "be"
+#else
+ "le"
+#endif
+ );
+ if (ret)
+ goto end;
+
+ /* ignore error, just use empty string if error. */
+ hostname[0] = '\0';
+ ret = gethostname(hostname, sizeof(hostname));
+ if (ret && errno == ENAMETOOLONG)
+ hostname[HOST_NAME_MAX - 1] = '\0';
+ lttng_ust_getprocname(procname);
+ procname[LTTNG_UST_PROCNAME_LEN - 1] = '\0';
+ ret = lttng_metadata_printf(session,
+ "env {\n"
+ " hostname = \"%s\";\n"
+ " vpid = %d;\n"
+ " procname = \"%s\";\n"
+ " domain = \"ust\";\n"
+ " tracer_name = \"lttng-ust\";\n"
+ " tracer_major = %u;\n"
+ " tracer_minor = %u;\n"
+ " tracer_patchlevel = %u;\n"
+ "};\n\n",
+ hostname,
+ (int) getpid(),
+ procname,
+ LTTNG_UST_MAJOR_VERSION,
+ LTTNG_UST_MINOR_VERSION,
+ LTTNG_UST_PATCHLEVEL_VERSION
+ );
+ if (ret)
+ goto end;
+
+ ret = lttng_metadata_printf(session,
+ "clock {\n"
+ " name = %s;\n",
+ "monotonic"
+ );
+ if (ret)
+ goto end;
+
+ if (!trace_clock_uuid(clock_uuid_s)) {
+ ret = lttng_metadata_printf(session,
+ " uuid = \"%s\";\n",
+ clock_uuid_s
+ );
+ if (ret)
+ goto end;
+ }
+
+ ret = lttng_metadata_printf(session,
+ " description = \"Monotonic Clock\";\n"
+ " freq = %" PRIu64 "; /* Frequency, in Hz */\n"
+ " /* clock value offset from Epoch is: offset * (1/freq) */\n"
+ " offset = %" PRIu64 ";\n"
+ "};\n\n",
+ trace_clock_freq(),
+ measure_clock_offset()
+ );
+ if (ret)
+ goto end;
+
+ ret = lttng_metadata_printf(session,
+ "typealias integer {\n"
+ " size = 27; align = 1; signed = false;\n"
+ " map = clock.monotonic.value;\n"
+ "} := uint27_clock_monotonic_t;\n"
+ "\n"
+ "typealias integer {\n"
+ " size = 32; align = %u; signed = false;\n"
+ " map = clock.monotonic.value;\n"
+ "} := uint32_clock_monotonic_t;\n"
+ "\n"
+ "typealias integer {\n"
+ " size = 64; align = %u; signed = false;\n"
+ " map = clock.monotonic.value;\n"
+ "} := uint64_clock_monotonic_t;\n\n",
+ lttng_alignof(uint32_t) * CHAR_BIT,
+ lttng_alignof(uint64_t) * CHAR_BIT
+ );
+ if (ret)
+ goto end;
+
+ ret = _lttng_stream_packet_context_declare(session);
+ if (ret)
+ goto end;
+
+ ret = _lttng_event_header_declare(session);
+ if (ret)
+ goto end;
+
+skip_session:
+ cds_list_for_each_entry(chan, &session->chan, list) {
+ ret = _lttng_channel_metadata_statedump(session, chan);
+ if (ret)
+ goto end;
+ }
+
+ cds_list_for_each_entry(event, &session->events, list) {
+ ret = _lttng_event_metadata_statedump(session, event->chan, event);
+ if (ret)
+ goto end;
+ }
+ session->metadata_dumped = 1;
+end:
+ return ret;
+}
+
+void lttng_ust_events_exit(void)
+{
+ struct lttng_session *session, *tmpsession;
+
+ cds_list_for_each_entry_safe(session, tmpsession, &sessions, list)
+ lttng_session_destroy(session);
+}
+
+/* WILDCARDS */
+
+static
+int wildcard_same_loglevel(struct wildcard_entry *e,
+ enum lttng_ust_loglevel_type loglevel_type,
+ int loglevel)
+{
+ if (e->loglevel_type == loglevel_type && e->loglevel == loglevel)
+ return 1;
+ else
+ return 0;
+}
+
+#if 0
+static
+int wildcard_is_within(struct wildcard_entry *e,
+ enum lttng_ust_loglevel_type loglevel_type,
+ int loglevel)
+{
+ if (e->loglevel_type == LTTNG_UST_LOGLEVEL_ALL
+ || e->loglevel == -1)
+ return 1;
+ switch (e->loglevel_type) {
+ case LTTNG_UST_LOGLEVEL_RANGE:
+ switch (loglevel_type) {
+ case LTTNG_UST_LOGLEVEL_RANGE:
+ if (e->loglevel >= loglevel)
+ return 1;
+ else
+ return 0;
+ case LTTNG_UST_LOGLEVEL_SINGLE:
+ if (e->loglevel <= 0 && loglevel == 0)
+ return 1;
+ else
+ return 0;
+ }
+ case LTTNG_UST_LOGLEVEL_SINGLE:
+ switch (loglevel_type) {
+ case LTTNG_UST_LOGLEVEL_RANGE:
+ if (loglevel <= 0)
+ return 1;
+ else
+ return 0;
+ case LTTNG_UST_LOGLEVEL_SINGLE:
+ if (e->loglevel == loglevel)
+ return 1;
+ else
+ return 0;
+ }
+ }
+}
+#endif
+
+/*
+ * Add the wildcard to the wildcard list. Must be called with
+ * ust lock held.
+ */
+static
+struct session_wildcard *add_wildcard(struct lttng_channel *chan,
+ struct lttng_ust_event *event_param)
+{
+ struct wildcard_entry *e;
+ struct session_wildcard *sw;
+ size_t name_len = strlen(event_param->name) + 1;
+ int found = 0;
+
+ //FIXME: ensure that wildcard re-use pending events, or
+ //re-use actual events, applying its filter on top.
+
+ /*
+ * Try to find global wildcard entry. Given that this is shared
+ * across all sessions, we need to check for exact loglevel
+ * match, not just whether contained within the existing ones.
+ */
+ cds_list_for_each_entry(e, &wildcard_list, list) {
+ if (!strncmp(event_param->name, e->name,
+ LTTNG_UST_SYM_NAME_LEN - 1)) {
+ if (wildcard_same_loglevel(e,
+ event_param->loglevel_type,
+ event_param->loglevel)) {
+ found = 1;
+ break;
+ }
+ }
+ }
+
+ if (!found) {
+ /*
+ * Create global wildcard entry if not found. Using
+ * zmalloc here to allocate a variable length element.
+ * Could cause some memory fragmentation if overused.
+ */
+ e = zmalloc(sizeof(struct wildcard_entry) + name_len);
+ if (!e)
+ return ERR_PTR(-ENOMEM);
+ memcpy(&e->name[0], event_param->name, name_len);
+ e->loglevel_type = event_param->loglevel_type;
+ e->loglevel = event_param->loglevel;
+ CDS_INIT_LIST_HEAD(&e->filter_bytecode);
+ cds_list_add(&e->list, &wildcard_list);
+ CDS_INIT_LIST_HEAD(&e->session_list);
+ }
+
+ /* session wildcard */
+ cds_list_for_each_entry(sw, &e->session_list, session_list) {
+ if (chan == sw->chan) {
+ DBG("wildcard %s busy for this channel",
+ event_param->name);
+ return ERR_PTR(-EEXIST); /* Already there */
+ }
+ }
+ sw = zmalloc(sizeof(struct session_wildcard));
+ if (!sw)
+ return ERR_PTR(-ENOMEM);
+ sw->chan = chan;
+ sw->enabled = 1;
+ memcpy(&sw->event_param, event_param, sizeof(sw->event_param));
+ sw->event_param.instrumentation = LTTNG_UST_TRACEPOINT;
+ sw->event_param.loglevel_type = event_param->loglevel_type;
+ sw->event_param.loglevel = event_param->loglevel;
+ CDS_INIT_LIST_HEAD(&sw->filter_bytecode);
+ CDS_INIT_LIST_HEAD(&sw->events);
+ cds_list_add(&sw->list, &chan->session->wildcards);
+ cds_list_add(&sw->session_list, &e->session_list);
+ sw->entry = e;
+ lttng_probes_create_wildcard_events(e, sw);
+ return sw;
+}
+
+/*
+ * Remove the wildcard from the wildcard list. Must be called with
+ * ust_lock held. Only called at session teardown.
+ */
+static
+void _remove_wildcard(struct session_wildcard *wildcard)
+{
+ struct lttng_event *ev, *tmp;
+
+ /*
+ * Just remove the events owned (for enable/disable) by this
+ * wildcard from the list. The session teardown will take care
+ * of freeing the event memory.
+ */
+ cds_list_for_each_entry_safe(ev, tmp, &wildcard->events,
+ wildcard_list) {
+ cds_list_del(&ev->wildcard_list);
+ }
+ cds_list_del(&wildcard->session_list);
+ cds_list_del(&wildcard->list);
+ if (cds_list_empty(&wildcard->entry->session_list)) {
+ cds_list_del(&wildcard->entry->list);
+ free(wildcard->entry);
+ }
+ lttng_free_wildcard_filter_bytecode(wildcard);
+ free(wildcard);
+}
+
+int lttng_wildcard_create(struct lttng_channel *chan,
+ struct lttng_ust_event *event_param,
+ struct session_wildcard **_sw)
+{
+ struct session_wildcard *sw;
+
+ sw = add_wildcard(chan, event_param);
+ if (!sw || IS_ERR(sw)) {
+ return PTR_ERR(sw);
+ }
+ *_sw = sw;
+ return 0;
+}
+
+static
+void _lttng_wildcard_destroy(struct session_wildcard *sw)
+{
+ _remove_wildcard(sw);
+}
+
+int lttng_wildcard_enable(struct session_wildcard *wildcard)
+{
+ struct lttng_event *ev;
+ int ret;
+
+ if (wildcard->enabled)
+ return -EEXIST;
+ cds_list_for_each_entry(ev, &wildcard->events, wildcard_list) {
+ ret = lttng_event_enable(ev);
+ if (ret) {
+ DBG("Error: enable error.\n");
+ return ret;
+ }
+ }
+ wildcard->enabled = 1;
+ return 0;
+}
+
+int lttng_wildcard_disable(struct session_wildcard *wildcard)
+{
+ struct lttng_event *ev;
+ int ret;
+
+ if (!wildcard->enabled)
+ return -EEXIST;
+ cds_list_for_each_entry(ev, &wildcard->events, wildcard_list) {
+ ret = lttng_event_disable(ev);
+ if (ret) {
+ DBG("Error: disable error.\n");
+ return ret;
+ }
+ }
+ wildcard->enabled = 0;
+ return 0;
+}
+
+/*
+ * Take the TLS "fault" in libuuid if dlopen'd, which can take the
+ * dynamic linker mutex, outside of the UST lock, since the UST lock is
+ * taken in constructors, which are called with dynamic linker mutex
+ * held.
+ */
+void lttng_fixup_event_tls(void)
+{
+ unsigned char uuid[LTTNG_UST_UUID_STR_LEN];
+
+ (void) lttng_ust_uuid_generate(uuid);
+}