X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fust-app.c;h=916cd882835d72573ba967af2b654e81238669cf;hp=0f553a671603845a6bdd40b9819505963d27c45b;hb=ecc48a904cc7c419fd1400afaa9ccb93be490cdd;hpb=d9078d0c000d04d49c599a72c1a725026b636ec0 diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c index 0f553a671..916cd8828 100644 --- a/src/bin/lttng-sessiond/ust-app.c +++ b/src/bin/lttng-sessiond/ust-app.c @@ -40,24 +40,38 @@ #include "ust-ctl.h" #include "utils.h" -/* Next available channel key. */ -static unsigned long next_channel_key; -static unsigned long next_session_id; +/* Next available channel key. Access under next_channel_key_lock. */ +static uint64_t _next_channel_key; +static pthread_mutex_t next_channel_key_lock = PTHREAD_MUTEX_INITIALIZER; + +/* Next available session ID. Access under next_session_id_lock. */ +static uint64_t _next_session_id; +static pthread_mutex_t next_session_id_lock = PTHREAD_MUTEX_INITIALIZER; /* - * Return the atomically incremented value of next_channel_key. + * Return the incremented value of next_channel_key. */ -static inline unsigned long get_next_channel_key(void) +static uint64_t get_next_channel_key(void) { - return uatomic_add_return(&next_channel_key, 1); + uint64_t ret; + + pthread_mutex_lock(&next_channel_key_lock); + ret = ++_next_channel_key; + pthread_mutex_unlock(&next_channel_key_lock); + return ret; } /* * Return the atomically incremented value of next_session_id. */ -static inline unsigned long get_next_session_id(void) +static uint64_t get_next_session_id(void) { - return uatomic_add_return(&next_session_id, 1); + uint64_t ret; + + pthread_mutex_lock(&next_session_id_lock); + ret = ++_next_session_id; + pthread_mutex_unlock(&next_session_id_lock); + return ret; } static void copy_channel_attr_to_ustctl( @@ -350,6 +364,7 @@ void delete_ust_app_channel(int sock, struct ust_app_channel *ua_chan, /* Wipe context */ cds_lfht_for_each_entry(ua_chan->ctx->ht, &iter.iter, ua_ctx, node.node) { + cds_list_del(&ua_ctx->list); ret = lttng_ht_del(ua_chan->ctx, &iter); assert(!ret); delete_ust_app_ctx(sock, ua_ctx); @@ -363,10 +378,12 @@ void delete_ust_app_channel(int sock, struct ust_app_channel *ua_chan, delete_ust_app_event(sock, ua_event); } - /* Wipe and free registry from session registry. */ - registry = get_session_registry(ua_chan->session); - if (registry) { - ust_registry_channel_del_free(registry, ua_chan->key); + if (ua_chan->session->buffer_type == LTTNG_BUFFER_PER_PID) { + /* Wipe and free registry from session registry. */ + registry = get_session_registry(ua_chan->session); + if (registry) { + ust_registry_channel_del_free(registry, ua_chan->key); + } } if (ua_chan->obj != NULL) { @@ -809,6 +826,7 @@ struct ust_app_channel *alloc_ust_app_channel(char *name, lttng_ht_node_init_str(&ua_chan->node, ua_chan->name); CDS_INIT_LIST_HEAD(&ua_chan->streams.head); + CDS_INIT_LIST_HEAD(&ua_chan->ctx_list); /* Copy attributes */ if (attr) { @@ -900,6 +918,8 @@ struct ust_app_ctx *alloc_ust_app_ctx(struct lttng_ust_context *uctx) goto error; } + CDS_INIT_LIST_HEAD(&ua_ctx->list); + if (uctx) { memcpy(&ua_ctx->ctx, uctx, sizeof(ua_ctx->ctx)); } @@ -1035,6 +1055,12 @@ int create_ust_channel_context(struct ust_app_channel *ua_chan, ERR("UST app create channel context failed for app (pid: %d) " "with ret %d", app->pid, ret); } else { + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. + */ + ret = 0; DBG3("UST app disable event failed. Application is dead."); } goto error; @@ -1073,6 +1099,12 @@ int set_ust_event_filter(struct ust_app_event *ua_event, ERR("UST app event %s filter failed for app (pid: %d) " "with ret %d", ua_event->attr.name, app->pid, ret); } else { + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. + */ + ret = 0; DBG3("UST app filter event failed. Application is dead."); } goto error; @@ -1102,6 +1134,12 @@ static int disable_ust_event(struct ust_app *app, "and session handle %d with ret %d", ua_event->attr.name, app->pid, ua_sess->handle, ret); } else { + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. + */ + ret = 0; DBG3("UST app disable event failed. Application is dead."); } goto error; @@ -1132,6 +1170,12 @@ static int disable_ust_channel(struct ust_app *app, "and session handle %d with ret %d", ua_chan->name, app->pid, ua_sess->handle, ret); } else { + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. + */ + ret = 0; DBG3("UST app disable channel failed. Application is dead."); } goto error; @@ -1162,6 +1206,12 @@ static int enable_ust_channel(struct ust_app *app, "and session handle %d with ret %d", ua_chan->name, app->pid, ua_sess->handle, ret); } else { + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. + */ + ret = 0; DBG3("UST app enable channel failed. Application is dead."); } goto error; @@ -1194,6 +1244,12 @@ static int enable_ust_event(struct ust_app *app, "and session handle %d with ret %d", ua_event->attr.name, app->pid, ua_sess->handle, ret); } else { + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. + */ + ret = 0; DBG3("UST app enable event failed. Application is dead."); } goto error; @@ -1274,6 +1330,12 @@ int create_ust_event(struct ust_app *app, struct ust_app_session *ua_sess, ERR("Error ustctl create event %s for app pid: %d with ret %d", ua_event->attr.name, app->pid, ret); } else { + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. + */ + ret = 0; DBG3("UST app create event failed. Application is dead."); } goto error; @@ -1379,7 +1441,7 @@ static void shadow_copy_channel(struct ust_app_channel *ua_chan, ua_chan->enabled = uchan->enabled; ua_chan->tracing_channel_id = uchan->id; - cds_lfht_for_each_entry(uchan->ctx->ht, &iter.iter, uctx, node.node) { + cds_list_for_each_entry(uctx, &uchan->ctx_list, list) { ua_ctx = alloc_ust_app_ctx(&uctx->ctx); if (ua_ctx == NULL) { continue; @@ -1387,6 +1449,7 @@ static void shadow_copy_channel(struct ust_app_channel *ua_chan, lttng_ht_node_init_ulong(&ua_ctx->node, (unsigned long) ua_ctx->ctx.ctx); lttng_ht_add_unique_ulong(ua_chan->ctx, &ua_ctx->node); + cds_list_add_tail(&ua_ctx->list, &ua_chan->ctx_list); } /* Copy all events from ltt ust channel to ust app channel */ @@ -1440,6 +1503,8 @@ static void shadow_copy_session(struct ust_app_session *ua_sess, ua_sess->bits_per_long = app->bits_per_long; /* There is only one consumer object per session possible. */ ua_sess->consumer = usess->consumer; + ua_sess->output_traces = usess->output_traces; + ua_sess->live_timer_interval = usess->live_timer_interval; switch (ua_sess->buffer_type) { case LTTNG_BUFFER_PER_PID: @@ -1503,7 +1568,7 @@ void __lookup_session_by_app(struct ltt_ust_session *usess, struct ust_app *app, struct lttng_ht_iter *iter) { /* Get right UST app session from app */ - lttng_ht_lookup(app->sessions, (void *)((unsigned long) usess->id), iter); + lttng_ht_lookup(app->sessions, &usess->id, iter); } /* @@ -1514,10 +1579,10 @@ static struct ust_app_session *lookup_session_by_app( struct ltt_ust_session *usess, struct ust_app *app) { struct lttng_ht_iter iter; - struct lttng_ht_node_ulong *node; + struct lttng_ht_node_u64 *node; __lookup_session_by_app(usess, app, &iter); - node = lttng_ht_iter_get_node_ulong(&iter); + node = lttng_ht_iter_get_node_u64(&iter); if (node == NULL) { goto error; } @@ -1667,7 +1732,7 @@ static int create_ust_app_session(struct ltt_ust_session *usess, ua_sess = lookup_session_by_app(usess, app); if (ua_sess == NULL) { - DBG2("UST app pid: %d session id %d not found, creating it", + DBG2("UST app pid: %d session id %" PRIu64 " not found, creating it", app->pid, usess->id); ua_sess = alloc_ust_app_session(app); if (ua_sess == NULL) { @@ -1710,6 +1775,13 @@ static int create_ust_app_session(struct ltt_ust_session *usess, app->pid, ret); } else { DBG("UST app creating session failed. Application is dead"); + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. This will get flagged ENOTCONN and the + * caller will handle it. + */ + ret = 0; } delete_ust_app_session(-1, ua_sess, app); if (ret != -ENOMEM) { @@ -1725,9 +1797,9 @@ static int create_ust_app_session(struct ltt_ust_session *usess, ua_sess->handle = ret; /* Add ust app session to app's HT */ - lttng_ht_node_init_ulong(&ua_sess->node, - (unsigned long) ua_sess->tracing_id); - lttng_ht_add_unique_ulong(app->sessions, &ua_sess->node); + lttng_ht_node_init_u64(&ua_sess->node, + ua_sess->tracing_id); + lttng_ht_add_unique_u64(app->sessions, &ua_sess->node); DBG2("UST app session created successfully with handle %d", ret); } @@ -1778,6 +1850,7 @@ int create_ust_app_channel_context(struct ust_app_session *ua_sess, lttng_ht_node_init_ulong(&ua_ctx->node, (unsigned long) ua_ctx->ctx.ctx); lttng_ht_add_unique_ulong(ua_chan->ctx, &ua_ctx->node); + cds_list_add_tail(&ua_ctx->list, &ua_chan->ctx_list); ret = create_ust_channel_context(ua_chan, ua_ctx, app); if (ret < 0) { @@ -1864,7 +1937,7 @@ static int enable_ust_app_channel(struct ust_app_session *ua_sess, lttng_ht_lookup(ua_sess->channels, (void *)uchan->name, &iter); ua_chan_node = lttng_ht_iter_get_node_str(&iter); if (ua_chan_node == NULL) { - DBG2("Unable to find channel %s in ust session id %u", + DBG2("Unable to find channel %s in ust session id %" PRIu64, uchan->name, ua_sess->tracing_id); goto error; } @@ -2117,6 +2190,7 @@ static int create_buffer_reg_channel(struct buffer_reg_session *reg_sess, } assert(reg_chan); reg_chan->consumer_key = ua_chan->key; + reg_chan->subbuf_size = ua_chan->attr.subbuf_size; /* Create and add a channel registry to session. */ ret = ust_registry_channel_add(reg_sess->reg.ust, @@ -2719,7 +2793,7 @@ struct ust_app *ust_app_create(struct ust_register_msg *msg, int sock) lta->v_major = msg->major; lta->v_minor = msg->minor; - lta->sessions = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG); + lta->sessions = lttng_ht_new(0, LTTNG_HT_TYPE_U64); lta->ust_objd = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG); lta->notify_sock = -1; @@ -2976,6 +3050,12 @@ int ust_app_list_events(struct lttng_event **events) app->sock, ret); } else { DBG3("UST app tp list get failed. Application is dead"); + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. Continue normal execution. + */ + break; } goto rcu_error; } @@ -3070,6 +3150,12 @@ int ust_app_list_event_fields(struct lttng_event_field **fields) app->sock, ret); } else { DBG3("UST app tp list field failed. Application is dead"); + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. + */ + break; } goto rcu_error; } @@ -3188,7 +3274,7 @@ int ust_app_disable_channel_glb(struct ltt_ust_session *usess, goto error; } - DBG2("UST app disabling channel %s from global domain for session id %d", + DBG2("UST app disabling channel %s from global domain for session id %" PRIu64, uchan->name, usess->id); rcu_read_lock(); @@ -3249,7 +3335,7 @@ int ust_app_enable_channel_glb(struct ltt_ust_session *usess, goto error; } - DBG2("UST app enabling channel %s to global domain for session id %d", + DBG2("UST app enabling channel %s to global domain for session id %" PRIu64, uchan->name, usess->id); rcu_read_lock(); @@ -3297,7 +3383,8 @@ int ust_app_disable_event_glb(struct ltt_ust_session *usess, struct ust_app_event *ua_event; DBG("UST app disabling event %s for all apps in channel " - "%s for session id %d", uevent->attr.name, uchan->name, usess->id); + "%s for session id %" PRIu64, + uevent->attr.name, uchan->name, usess->id); rcu_read_lock(); @@ -3320,7 +3407,7 @@ int ust_app_disable_event_glb(struct ltt_ust_session *usess, lttng_ht_lookup(ua_sess->channels, (void *)uchan->name, &uiter); ua_chan_node = lttng_ht_iter_get_node_str(&uiter); if (ua_chan_node == NULL) { - DBG2("Channel %s not found in session id %d for app pid %d." + DBG2("Channel %s not found in session id %" PRIu64 " for app pid %d." "Skipping", uchan->name, usess->id, app->pid); continue; } @@ -3363,7 +3450,7 @@ int ust_app_disable_all_event_glb(struct ltt_ust_session *usess, struct ust_app_event *ua_event; DBG("UST app disabling all event for all apps in channel " - "%s for session id %d", uchan->name, usess->id); + "%s for session id %" PRIu64, uchan->name, usess->id); rcu_read_lock(); @@ -3421,7 +3508,7 @@ int ust_app_create_channel_glb(struct ltt_ust_session *usess, assert(usess); assert(uchan); - DBG2("UST app adding channel %s to UST domain for session id %d", + DBG2("UST app adding channel %s to UST domain for session id %" PRIu64, uchan->name, usess->id); rcu_read_lock(); @@ -3501,7 +3588,7 @@ int ust_app_enable_event_glb(struct ltt_ust_session *usess, struct ust_app_channel *ua_chan; struct ust_app_event *ua_event; - DBG("UST app enabling event %s for all apps for session id %d", + DBG("UST app enabling event %s for all apps for session id %" PRIu64, uevent->attr.name, usess->id); /* @@ -3574,7 +3661,7 @@ int ust_app_create_event_glb(struct ltt_ust_session *usess, struct ust_app_session *ua_sess; struct ust_app_channel *ua_chan; - DBG("UST app creating event %s for all apps for session id %d", + DBG("UST app creating event %s for all apps for session id %" PRIu64, uevent->attr.name, usess->id); rcu_read_lock(); @@ -3684,6 +3771,13 @@ skip_setup: app->pid, ret); } else { DBG("UST app start session failed. Application is dead."); + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. + */ + pthread_mutex_unlock(&ua_sess->lock); + goto end; } goto error_unlock; } @@ -3759,6 +3853,12 @@ int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app) app->pid, ret); } else { DBG("UST app stop session failed. Application is dead."); + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. + */ + goto end_unlock; } goto error_rcu_unlock; } @@ -3782,6 +3882,7 @@ int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app) (void) push_metadata(registry, ua_sess->consumer); } +end_unlock: pthread_mutex_unlock(&ua_sess->lock); end_no_session: rcu_read_unlock(); @@ -3836,8 +3937,11 @@ int ust_app_flush_trace(struct ltt_ust_session *usess, struct ust_app *app) } else { DBG3("UST app failed to flush %s. Application is dead.", ua_chan->name); - /* No need to continue. */ - break; + /* + * This is normal behavior, an application can die during the + * creation process. Don't report an error so the execution can + * continue normally. + */ } /* Continuing flushing all buffers */ continue; @@ -3861,7 +3965,7 @@ static int destroy_trace(struct ltt_ust_session *usess, struct ust_app *app) int ret; struct ust_app_session *ua_sess; struct lttng_ht_iter iter; - struct lttng_ht_node_ulong *node; + struct lttng_ht_node_u64 *node; DBG("Destroy tracing for ust app pid %d", app->pid); @@ -3872,7 +3976,7 @@ static int destroy_trace(struct ltt_ust_session *usess, struct ust_app *app) } __lookup_session_by_app(usess, app, &iter); - node = lttng_ht_iter_get_node_ulong(&iter); + node = lttng_ht_iter_get_node_u64(&iter); if (node == NULL) { /* Session is being or is deleted. */ goto end; @@ -3943,7 +4047,7 @@ int ust_app_stop_trace_all(struct ltt_ust_session *usess) } } - /* Flush buffers */ + /* Flush buffers and push metadata (for UID buffers). */ switch (usess->buffer_type) { case LTTNG_BUFFER_PER_UID: { @@ -3951,6 +4055,7 @@ int ust_app_stop_trace_all(struct ltt_ust_session *usess) /* Flush all per UID buffers associated to that session. */ cds_list_for_each_entry(reg, &usess->buffer_reg_uid_list, lnode) { + struct ust_registry_session *ust_session_reg; struct buffer_reg_channel *reg_chan; struct consumer_socket *socket; @@ -3971,7 +4076,14 @@ int ust_app_stop_trace_all(struct ltt_ust_session *usess) */ (void) consumer_flush_channel(socket, reg_chan->consumer_key); } + + ust_session_reg = reg->registry->reg.ust; + if (!ust_session_reg->metadata_closed) { + /* Push metadata. */ + (void) push_metadata(ust_session_reg, usess->consumer); + } } + break; } case LTTNG_BUFFER_PER_PID: @@ -4025,7 +4137,7 @@ int ust_app_destroy_trace_all(struct ltt_ust_session *usess) void ust_app_global_update(struct ltt_ust_session *usess, int sock) { int ret = 0; - struct lttng_ht_iter iter, uiter, iter_ctx; + struct lttng_ht_iter iter, uiter; struct ust_app *app; struct ust_app_session *ua_sess = NULL; struct ust_app_channel *ua_chan; @@ -4035,7 +4147,7 @@ void ust_app_global_update(struct ltt_ust_session *usess, int sock) assert(usess); assert(sock >= 0); - DBG2("UST app global update for app sock %d for session id %d", sock, + DBG2("UST app global update for app sock %d for session id %" PRIu64, sock, usess->id); rcu_read_lock(); @@ -4097,8 +4209,11 @@ void ust_app_global_update(struct ltt_ust_session *usess, int sock) } } - cds_lfht_for_each_entry(ua_chan->ctx->ht, &iter_ctx.iter, ua_ctx, - node.node) { + /* + * Add context using the list so they are enabled in the same order the + * user added them. + */ + cds_list_for_each_entry(ua_ctx, &ua_chan->ctx_list, list) { ret = create_ust_channel_context(ua_chan, ua_ctx, app); if (ret < 0) { goto error_unlock; @@ -4628,7 +4743,8 @@ static int add_event_ust_registry(int sock, int sobjd, int cobjd, char *name, */ ret_code = ust_registry_create_event(registry, chan_reg_key, sobjd, cobjd, name, sig, nr_fields, fields, loglevel, - model_emf_uri, ua_sess->buffer_type, &event_id); + model_emf_uri, ua_sess->buffer_type, &event_id, + app); /* * The return value is returned to ustctl so in case of an error, the @@ -4845,3 +4961,223 @@ void ust_app_destroy(struct ust_app *app) call_rcu(&app->pid_n.head, delete_ust_app_rcu); } + +/* + * Take a snapshot for a given UST session. The snapshot is sent to the given + * output. + * + * Return 0 on success or else a negative value. + */ +int ust_app_snapshot_record(struct ltt_ust_session *usess, + struct snapshot_output *output, int wait, unsigned int nb_streams) +{ + int ret = 0; + struct lttng_ht_iter iter; + struct ust_app *app; + char pathname[PATH_MAX]; + uint64_t max_stream_size = 0; + + assert(usess); + assert(output); + + rcu_read_lock(); + + /* + * Compute the maximum size of a single stream if a max size is asked by + * the caller. + */ + if (output->max_size > 0 && nb_streams > 0) { + max_stream_size = output->max_size / nb_streams; + } + + switch (usess->buffer_type) { + case LTTNG_BUFFER_PER_UID: + { + struct buffer_reg_uid *reg; + + cds_list_for_each_entry(reg, &usess->buffer_reg_uid_list, lnode) { + struct buffer_reg_channel *reg_chan; + struct consumer_socket *socket; + + /* Get consumer socket to use to push the metadata.*/ + socket = consumer_find_socket_by_bitness(reg->bits_per_long, + usess->consumer); + if (!socket) { + ret = -EINVAL; + goto error; + } + + memset(pathname, 0, sizeof(pathname)); + ret = snprintf(pathname, sizeof(pathname), + DEFAULT_UST_TRACE_DIR "/" DEFAULT_UST_TRACE_UID_PATH, + reg->uid, reg->bits_per_long); + if (ret < 0) { + PERROR("snprintf snapshot path"); + goto error; + } + + /* Add the UST default trace dir to path. */ + cds_lfht_for_each_entry(reg->registry->channels->ht, &iter.iter, + reg_chan, node.node) { + + /* + * Make sure the maximum stream size is not lower than the + * subbuffer size or else it's an error since we won't be able to + * snapshot anything. + */ + if (max_stream_size && + reg_chan->subbuf_size > max_stream_size) { + ret = -EINVAL; + DBG3("UST app snapshot record maximum stream size %" PRIu64 + " is smaller than subbuffer size of %zu", + max_stream_size, reg_chan->subbuf_size); + goto error; + } + ret = consumer_snapshot_channel(socket, reg_chan->consumer_key, output, 0, + usess->uid, usess->gid, pathname, wait, + max_stream_size); + if (ret < 0) { + goto error; + } + } + ret = consumer_snapshot_channel(socket, reg->registry->reg.ust->metadata_key, output, + 1, usess->uid, usess->gid, pathname, wait, + max_stream_size); + if (ret < 0) { + goto error; + } + } + break; + } + case LTTNG_BUFFER_PER_PID: + { + cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) { + struct consumer_socket *socket; + struct lttng_ht_iter chan_iter; + struct ust_app_channel *ua_chan; + struct ust_app_session *ua_sess; + struct ust_registry_session *registry; + + ua_sess = lookup_session_by_app(usess, app); + if (!ua_sess) { + /* Session not associated with this app. */ + continue; + } + + /* Get the right consumer socket for the application. */ + socket = consumer_find_socket_by_bitness(app->bits_per_long, + output->consumer); + if (!socket) { + ret = -EINVAL; + goto error; + } + + /* Add the UST default trace dir to path. */ + memset(pathname, 0, sizeof(pathname)); + ret = snprintf(pathname, sizeof(pathname), DEFAULT_UST_TRACE_DIR "/%s", + ua_sess->path); + if (ret < 0) { + PERROR("snprintf snapshot path"); + goto error; + } + + cds_lfht_for_each_entry(ua_sess->channels->ht, &chan_iter.iter, + ua_chan, node.node) { + /* + * Make sure the maximum stream size is not lower than the + * subbuffer size or else it's an error since we won't be able to + * snapshot anything. + */ + if (max_stream_size && + ua_chan->attr.subbuf_size > max_stream_size) { + ret = -EINVAL; + DBG3("UST app snapshot record maximum stream size %" PRIu64 + " is smaller than subbuffer size of %" PRIu64, + max_stream_size, ua_chan->attr.subbuf_size); + goto error; + } + + ret = consumer_snapshot_channel(socket, ua_chan->key, output, 0, + ua_sess->euid, ua_sess->egid, pathname, wait, + max_stream_size); + if (ret < 0) { + goto error; + } + } + + registry = get_session_registry(ua_sess); + assert(registry); + ret = consumer_snapshot_channel(socket, registry->metadata_key, output, + 1, ua_sess->euid, ua_sess->egid, pathname, wait, + max_stream_size); + if (ret < 0) { + goto error; + } + } + break; + } + default: + assert(0); + break; + } + +error: + rcu_read_unlock(); + return ret; +} + +/* + * Return the number of streams for a UST session. + */ +unsigned int ust_app_get_nb_stream(struct ltt_ust_session *usess) +{ + unsigned int ret = 0; + struct ust_app *app; + struct lttng_ht_iter iter; + + assert(usess); + + switch (usess->buffer_type) { + case LTTNG_BUFFER_PER_UID: + { + struct buffer_reg_uid *reg; + + cds_list_for_each_entry(reg, &usess->buffer_reg_uid_list, lnode) { + struct buffer_reg_channel *reg_chan; + + cds_lfht_for_each_entry(reg->registry->channels->ht, &iter.iter, + reg_chan, node.node) { + ret += reg_chan->stream_count; + } + } + break; + } + case LTTNG_BUFFER_PER_PID: + { + rcu_read_lock(); + cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) { + struct ust_app_channel *ua_chan; + struct ust_app_session *ua_sess; + struct lttng_ht_iter chan_iter; + + ua_sess = lookup_session_by_app(usess, app); + if (!ua_sess) { + /* Session not associated with this app. */ + continue; + } + + cds_lfht_for_each_entry(ua_sess->channels->ht, &chan_iter.iter, + ua_chan, node.node) { + ret += ua_chan->streams.count; + } + } + rcu_read_unlock(); + break; + } + default: + assert(0); + break; + } + + return ret; +}