}
socket = consumer_find_socket(consumer_fd, consumer);
+ if (!socket) {
+ ERR("Consumer socket fd %d not found in consumer obj %p",
+ consumer_fd, consumer);
+ }
end:
return socket;
assert(node_ptr == &event->node.node);
}
+/*
+ * Close the notify socket from the given RCU head object. This MUST be called
+ * through a call_rcu().
+ */
+static void close_notify_sock_rcu(struct rcu_head *head)
+{
+ int ret;
+ struct ust_app_notify_sock_obj *obj =
+ caa_container_of(head, struct ust_app_notify_sock_obj, head);
+
+ /* Must have a valid fd here. */
+ assert(obj->fd >= 0);
+
+ ret = close(obj->fd);
+ if (ret) {
+ ERR("close notify sock %d RCU", obj->fd);
+ }
+ lttng_fd_put(LTTNG_FD_APPS, 1);
+
+ free(obj);
+}
+
/*
* Delete ust context safely. RCU read lock must be held before calling
* this function.
free(ua_chan);
}
+/*
+ * For a given application and session, push metadata to consumer. The session
+ * lock MUST be acquired here before calling this.
+ *
+ * Return 0 on success else a negative error.
+ */
+static int push_metadata(struct ust_app *app, struct ust_app_session *ua_sess)
+{
+ int ret;
+ char *metadata_str = NULL;
+ size_t len, offset;
+ struct consumer_socket *socket;
+
+ assert(app);
+ assert(ua_sess);
+
+ if (!ua_sess->consumer || !ua_sess->metadata) {
+ /* No consumer means no stream associated so just return gracefully. */
+ ret = 0;
+ goto end;
+ }
+
+ rcu_read_lock();
+
+ /* Get consumer socket to use to push the metadata.*/
+ socket = find_consumer_socket_by_bitness(app->bits_per_long,
+ ua_sess->consumer);
+ if (!socket) {
+ ret = -1;
+ goto error_rcu_unlock;
+ }
+
+ /*
+ * TODO: Currently, we hold the socket lock around sampling of the next
+ * metadata segment to ensure we send metadata over the consumer socket in
+ * the correct order. This makes the registry lock nest inside the socket
+ * lock.
+ *
+ * Please note that this is a temporary measure: we should move this lock
+ * back into ust_consumer_push_metadata() when the consumer gets the
+ * ability to reorder the metadata it receives.
+ */
+ pthread_mutex_lock(socket->lock);
+ pthread_mutex_lock(&ua_sess->registry.lock);
+
+ offset = ua_sess->registry.metadata_len_sent;
+ len = ua_sess->registry.metadata_len - ua_sess->registry.metadata_len_sent;
+ if (len == 0) {
+ DBG3("No metadata to push for session id %d", ua_sess->id);
+ ret = 0;
+ goto error_reg_unlock;
+ }
+ assert(len > 0);
+
+ /* Allocate only what we have to send. */
+ metadata_str = zmalloc(len);
+ if (!metadata_str) {
+ PERROR("zmalloc ust app metadata string");
+ ret = -ENOMEM;
+ goto error_reg_unlock;
+ }
+ /* Copy what we haven't send out. */
+ memcpy(metadata_str, ua_sess->registry.metadata + offset, len);
+
+ pthread_mutex_unlock(&ua_sess->registry.lock);
+
+ ret = ust_consumer_push_metadata(socket, ua_sess, metadata_str, len,
+ offset);
+ if (ret < 0) {
+ pthread_mutex_unlock(socket->lock);
+ goto error_rcu_unlock;
+ }
+
+ /* Update len sent of the registry. */
+ pthread_mutex_lock(&ua_sess->registry.lock);
+ ua_sess->registry.metadata_len_sent += len;
+ pthread_mutex_unlock(&ua_sess->registry.lock);
+ pthread_mutex_unlock(socket->lock);
+
+ rcu_read_unlock();
+ free(metadata_str);
+ return 0;
+
+error_reg_unlock:
+ pthread_mutex_unlock(&ua_sess->registry.lock);
+ pthread_mutex_unlock(socket->lock);
+error_rcu_unlock:
+ rcu_read_unlock();
+ free(metadata_str);
+end:
+ return ret;
+}
+
+/*
+ * Send to the consumer a close metadata command for the given session. Once
+ * done, the metadata channel is deleted and the session metadata pointer is
+ * nullified. The session lock MUST be acquired here unless the application is
+ * in the destroy path.
+ *
+ * Return 0 on success else a negative value.
+ */
+static int close_metadata(struct ust_app *app, struct ust_app_session *ua_sess)
+{
+ int ret;
+ struct consumer_socket *socket;
+
+ assert(app);
+ assert(ua_sess);
+
+ /* Ignore if no metadata. Valid since it can be called on unregister. */
+ if (!ua_sess->metadata) {
+ ret = 0;
+ goto error;
+ }
+
+ rcu_read_lock();
+
+ /* Get consumer socket to use to push the metadata.*/
+ socket = find_consumer_socket_by_bitness(app->bits_per_long,
+ ua_sess->consumer);
+ if (!socket) {
+ ret = -1;
+ goto error_rcu_unlock;
+ }
+
+ ret = ust_consumer_close_metadata(socket, ua_sess->metadata);
+ if (ret < 0) {
+ goto error_rcu_unlock;
+ }
+
+error_rcu_unlock:
+ /* Destroy metadata on our side since we must not use it anymore. */
+ delete_ust_app_channel(-1, ua_sess->metadata, app);
+ ua_sess->metadata = NULL;
+
+ rcu_read_unlock();
+error:
+ return ret;
+}
+
/*
* Delete ust app session safely. RCU read lock must be held before calling
* this function.
struct lttng_ht_iter iter;
struct ust_app_channel *ua_chan;
+ assert(ua_sess);
+
if (ua_sess->metadata) {
- delete_ust_app_channel(sock, ua_sess->metadata, app);
+ /* Push metadata for application before freeing the application. */
+ (void) push_metadata(app, ua_sess);
+
+ /* And ask to close it for this session. */
+ (void) close_metadata(app, ua_sess);
}
cds_lfht_for_each_entry(ua_sess->channels->ht, &iter.iter, ua_chan,
}
/*
- * Create the specified channel onto the UST tracer for a UST session.
- * Called with UST app session lock held.
+ * Create the specified channel onto the UST tracer for a UST session. This
+ * MUST be called with UST app session lock held.
*
* Return 0 on success. On error, a negative value is returned.
*/
assert(ua_chan);
assert(consumer);
+ rcu_read_lock();
health_code_update();
/* Get the right consumer socket for the application. */
/*
* Compute the number of fd needed before receiving them. It must be 2 per
- * stream.
+ * stream (2 being the default value here).
*/
nb_fd = DEFAULT_UST_STREAM_FD_NUM * ua_chan->expected_stream_count;
goto error;
}
+ health_code_update();
+
/* Send all streams to application. */
cds_list_for_each_entry_safe(stream, stmp, &ua_chan->streams.head, list) {
ret = ust_consumer_send_stream_to_ust(app, ua_chan, stream);
}
}
+ rcu_read_unlock();
return 0;
error_destroy:
(void) ust_consumer_destroy_channel(socket, ua_chan);
error:
health_code_update();
+ rcu_read_unlock();
return ret;
}
DBG2("UST app session created successfully with handle %d", ret);
}
+ /*
+ * Assign consumer if not already set. For one application, there is only
+ * one possible consumer has of now.
+ */
+ if (!ua_sess->consumer) {
+ ua_sess->consumer = usess->consumer;
+ }
+
*ua_sess_ptr = ua_sess;
if (is_created) {
*is_created = created;
}
+
/* Everything went well. */
ret = 0;
{
int ret = 0;
struct ust_app_channel *metadata;
+ struct consumer_socket *socket;
assert(ua_sess);
assert(app);
+ assert(consumer);
if (ua_sess->metadata) {
/* Already exist. Return success. */
metadata->attr.output = LTTNG_UST_MMAP;
metadata->attr.type = LTTNG_UST_CHAN_METADATA;
- ret = create_ust_channel(app, ua_sess, metadata, consumer);
+ /* Get the right consumer socket for the application. */
+ socket = find_consumer_socket_by_bitness(app->bits_per_long, consumer);
+ if (!socket) {
+ ret = -EINVAL;
+ goto error_consumer;
+ }
+
+ /*
+ * Ask the metadata channel creation to the consumer. The metadata object
+ * will be created by the consumer and kept their. However, the stream is
+ * never added or monitored until we do a first push metadata to the
+ * consumer.
+ */
+ ret = ust_consumer_ask_channel(ua_sess, metadata, consumer, socket);
+ if (ret < 0) {
+ goto error_consumer;
+ }
+
+ /*
+ * The setup command will make the metadata stream be sent to the relayd,
+ * if applicable, and the thread managing the metadatas. This is important
+ * because after this point, if an error occurs, the only way the stream
+ * can be deleted is to be monitored in the consumer.
+ */
+ ret = ust_consumer_setup_metadata(socket, metadata);
if (ret < 0) {
- goto error_create;
+ goto error_consumer;
}
ua_sess->metadata = metadata;
- DBG2("UST metadata opened for app pid %d", app->pid);
+ DBG2("UST metadata created for app pid %d", app->pid);
end:
return 0;
-error_create:
- delete_ust_app_channel(metadata->is_sent ? app->sock : -1, metadata, app);
+error_consumer:
+ delete_ust_app_channel(-1, metadata, app);
error:
return ret;
}
}
/*
- * Return ust app pointer or NULL if not found.
+ * Return ust app pointer or NULL if not found. RCU read side lock MUST be
+ * acquired before calling this function.
*/
struct ust_app *ust_app_find_by_pid(pid_t pid)
{
+ struct ust_app *app = NULL;
struct lttng_ht_node_ulong *node;
struct lttng_ht_iter iter;
DBG2("Found UST app by pid %d", pid);
- return caa_container_of(node, struct ust_app, pid_n);
+ app = caa_container_of(node, struct ust_app, pid_n);
error:
- rcu_read_unlock();
- return NULL;
+ return app;
}
+/*
+ * Allocate and init an UST app object using the registration information and
+ * the command socket. This is called when the command socket connects to the
+ * session daemon.
+ *
+ * The object is returned on success or else NULL.
+ */
struct ust_app *ust_app_create(struct ust_register_msg *msg, int sock)
{
struct ust_app *lta = NULL;
lta->ppid = msg->ppid;
lta->uid = msg->uid;
lta->gid = msg->gid;
- lta->compatible = 0; /* Not compatible until proven */
lta->bits_per_long = msg->bits_per_long;
lta->uint8_t_alignment = msg->uint8_t_alignment;
lta->v_major = msg->major;
lta->v_minor = msg->minor;
- strncpy(lta->name, msg->name, sizeof(lta->name));
- lta->name[LTTNG_UST_ABI_PROCNAME_LEN] = '\0';
lta->sessions = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
lta->ust_objd = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
lta->notify_sock = -1;
+
+ /* Copy name and make sure it's NULL terminated. */
+ strncpy(lta->name, msg->name, sizeof(lta->name));
+ lta->name[UST_APP_PROCNAME_LEN] = '\0';
+
+ /*
+ * Before this can be called, when receiving the registration information,
+ * the application compatibility is checked. So, at this point, the
+ * application can work with this session daemon.
+ */
lta->compatible = 1;
lta->pid = msg->pid;
return lta;
}
+/*
+ * For a given application object, add it to every hash table.
+ */
void ust_app_add(struct ust_app *app)
{
assert(app);
lttng_ht_add_unique_ulong(ust_app_ht_by_notify_sock, &app->notify_sock_n);
DBG("App registered with pid:%d ppid:%d uid:%d gid:%d sock:%d name:%s "
- "(version %d.%d)", app->pid, app->ppid, app->uid, app->gid,
- app->sock, app->name, app->v_major, app->v_minor);
+ "notify_sock:%d (version %d.%d)", app->pid, app->ppid, app->uid,
+ app->gid, app->sock, app->name, app->notify_sock, app->v_major,
+ app->v_minor);
rcu_read_unlock();
}
+/*
+ * Set the application version into the object.
+ *
+ * Return 0 on success else a negative value either an errno code or a
+ * LTTng-UST error code.
+ */
int ust_app_version(struct ust_app *app)
{
+ int ret;
+
assert(app);
- return ustctl_tracer_version(app->sock, &app->version);
+
+ ret = ustctl_tracer_version(app->sock, &app->version);
+ if (ret < 0) {
+ if (ret != -LTTNG_UST_ERR_EXITING && ret != -EPIPE) {
+ ERR("UST app %d verson failed with ret %d", app->sock, ret);
+ } else {
+ DBG3("UST app %d verion failed. Application is dead", app->sock);
+ }
+ }
+
+ return ret;
}
/*
ret = lttng_ht_del(ust_app_ht_by_sock, &iter);
assert(!ret);
- /* Remove application from notify hash table */
+ /*
+ * Remove application from notify hash table. The thread handling the
+ * notify socket could have deleted the node so ignore on error because
+ * either way it's valid. The close of that socket is handled by the other
+ * thread.
+ */
iter.iter.node = <a->notify_sock_n.node;
- ret = lttng_ht_del(ust_app_ht_by_notify_sock, &iter);
+ (void) lttng_ht_del(ust_app_ht_by_notify_sock, &iter);
/*
* Ignore return value since the node might have been removed before by an
* Add session to list for teardown. This is safe since at this point we
* are the only one using this list.
*/
+ pthread_mutex_lock(&ua_sess->lock);
+
+ /*
+ * Normally, this is done in the delete session process which is
+ * executed in the call rcu below. However, upon registration we can't
+ * afford to wait for the grace period before pushing data or else the
+ * data pending feature can race between the unregistration and stop
+ * command where the data pending command is sent *before* the grace
+ * period ended.
+ *
+ * The close metadata below nullifies the metadata pointer in the
+ * session so the delete session will NOT push/close a second time.
+ */
+ (void) push_metadata(lta, ua_sess);
+ (void) close_metadata(lta, ua_sess);
+
cds_list_add(&ua_sess->teardown_node, <a->teardown_head);
+ pthread_mutex_unlock(&ua_sess->lock);
}
/* Free memory */
assert(!ret);
}
+ /* Cleanup notify socket hash table */
+ cds_lfht_for_each_entry(ust_app_ht_by_notify_sock->ht, &iter.iter, app,
+ notify_sock_n.node) {
+ ret = lttng_ht_del(ust_app_ht_by_notify_sock, &iter);
+ assert(!ret);
+ }
+
/* Destroy is done only when the ht is empty */
lttng_ht_destroy(ust_app_ht);
lttng_ht_destroy(ust_app_ht_by_sock);
+ lttng_ht_destroy(ust_app_ht_by_notify_sock);
rcu_read_unlock();
}
rcu_read_lock();
if (!app->compatible) {
- goto end;
+ goto end_no_session;
}
ua_sess = lookup_session_by_app(usess, app);
if (ua_sess == NULL) {
- goto end;
+ goto end_no_session;
}
+ pthread_mutex_lock(&ua_sess->lock);
+
/*
* If started = 0, it means that stop trace has been called for a session
* that was never started. It's possible since we can have a fail start
DBG3("UST app failed to flush %s. Application is dead.",
ua_chan->name);
/* No need to continue. */
- goto end;
+ break;
}
/* Continuing flushing all buffers */
continue;
health_code_update();
- assert(ua_sess->metadata->is_sent);
- /* Flush all buffers before stopping */
- ret = ustctl_sock_flush_buffer(app->sock, ua_sess->metadata->obj);
+ ret = push_metadata(app, ua_sess);
if (ret < 0) {
- if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
- ERR("UST app PID %d metadata flush failed with ret %d", app->pid,
- ret);
- goto error_rcu_unlock;
- } else {
- DBG3("UST app failed to flush metadata. Application is dead.");
- }
+ goto error_rcu_unlock;
}
-end:
+ pthread_mutex_unlock(&ua_sess->lock);
+end_no_session:
rcu_read_unlock();
health_code_update();
return 0;
error_rcu_unlock:
+ pthread_mutex_unlock(&ua_sess->lock);
rcu_read_unlock();
health_code_update();
return -1;
ERR("UST app wait quiescent failed for app pid %d ret %d",
app->pid, ret);
}
-
end:
rcu_read_unlock();
health_code_update();
cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
ret = ust_app_stop_trace(usess, app);
if (ret < 0) {
+ ERR("UST app stop trace failed with ret %d", ret);
/* Continue to next apps even on error */
continue;
}
app = find_app_by_sock(sock);
if (app == NULL) {
- ERR("Failed to find app sock %d", sock);
+ /*
+ * Application can be unregistered before so this is possible hence
+ * simply stopping the update.
+ */
+ DBG3("UST app update failed to find app sock %d", sock);
goto error;
}
return ret;
}
+/*
+ * Return a ust app channel object using the application object and the channel
+ * object descriptor has a key. If not found, NULL is returned. A RCU read side
+ * lock MUST be acquired before calling this function.
+ */
static struct ust_app_channel *find_channel_by_objd(struct ust_app *app,
int objd)
{
return ua_chan;
}
+/*
+ * Reply to a register channel notification from an application on the notify
+ * socket. The channel metadata is also created.
+ *
+ * The session UST registry lock is acquired in this function.
+ *
+ * On success 0 is returned else a negative value.
+ */
static int reply_ust_register_channel(int sock, int sobjd, int cobjd,
size_t nr_fields, struct ustctl_field *fields)
{
/* Lookup application. If not found, there is a code flow error. */
app = find_app_by_notify_sock(sock);
- assert(app);
+ if (!app) {
+ DBG("Application socket %d is being teardown. Abort event notify",
+ sock);
+ ret = 0;
+ goto error_rcu_unlock;
+ }
/* Lookup channel by UST object descriptor. Should always be found. */
ua_chan = find_channel_by_objd(app, cobjd);
error:
pthread_mutex_unlock(&ua_sess->registry.lock);
+error_rcu_unlock:
rcu_read_unlock();
return ret;
}
+/*
+ * Add event to the UST channel registry. When the event is added to the
+ * registry, the metadata is also created. Once done, this replies to the
+ * application with the appropriate error code.
+ *
+ * The session UST registry lock is acquired in the function.
+ *
+ * On success 0 is returned else a negative value.
+ */
static int add_event_ust_registry(int sock, int sobjd, int cobjd, char *name,
char *sig, size_t nr_fields, struct ustctl_field *fields, int loglevel,
char *model_emf_uri)
/* Lookup application. If not found, there is a code flow error. */
app = find_app_by_notify_sock(sock);
- assert(app);
+ if (!app) {
+ DBG("Application socket %d is being teardown. Abort event notify",
+ sock);
+ ret = 0;
+ goto error_rcu_unlock;
+ }
/* Lookup channel by UST object descriptor. Should always be found. */
ua_chan = find_channel_by_objd(app, cobjd);
pthread_mutex_lock(&ua_sess->registry.lock);
- ret_code = ust_registry_create_event(&ua_sess->registry, &ua_chan->registry, sobjd, cobjd,
- name, sig, nr_fields, fields, loglevel, model_emf_uri, &event_id);
+ ret_code = ust_registry_create_event(&ua_sess->registry,
+ &ua_chan->registry, sobjd, cobjd, name, sig, nr_fields, fields,
+ loglevel, model_emf_uri, &event_id);
/*
* The return value is returned to ustctl so in case of an error, the
goto error;
}
+ DBG3("UST registry event %s has been added successfully", name);
+
error:
pthread_mutex_unlock(&ua_sess->registry.lock);
+error_rcu_unlock:
rcu_read_unlock();
return ret;
}
+/*
+ * Handle application notification through the given notify socket.
+ *
+ * Return 0 on success or else a negative value.
+ */
int ust_app_recv_notify(int sock)
{
int ret;
error:
return ret;
}
+
+/*
+ * Once the notify socket hangs up, this is called. First, it tries to find the
+ * corresponding application. On failure, the call_rcu to close the socket is
+ * executed. If an application is found, it tries to delete it from the notify
+ * socket hash table. Whathever the result, it proceeds to the call_rcu.
+ *
+ * Note that an object needs to be allocated here so on ENOMEM failure, the
+ * call RCU is not done but the rest of the cleanup is.
+ */
+void ust_app_notify_sock_unregister(int sock)
+{
+ int err_enomem = 0;
+ struct lttng_ht_iter iter;
+ struct ust_app *app;
+ struct ust_app_notify_sock_obj *obj;
+
+ assert(sock >= 0);
+
+ rcu_read_lock();
+
+ obj = zmalloc(sizeof(*obj));
+ if (!obj) {
+ /*
+ * An ENOMEM is kind of uncool. If this strikes we continue the
+ * procedure but the call_rcu will not be called. In this case, we
+ * accept the fd leak rather than possibly creating an unsynchronized
+ * state between threads.
+ *
+ * TODO: The notify object should be created once the notify socket is
+ * registered and stored independantely from the ust app object. The
+ * tricky part is to synchronize the teardown of the application and
+ * this notify object. Let's keep that in mind so we can avoid this
+ * kind of shenanigans with ENOMEM in the teardown path.
+ */
+ err_enomem = 1;
+ } else {
+ obj->fd = sock;
+ }
+
+ DBG("UST app notify socket unregister %d", sock);
+
+ /*
+ * Lookup application by notify socket. If this fails, this means that the
+ * hash table delete has already been done by the application
+ * unregistration process so we can safely close the notify socket in a
+ * call RCU.
+ */
+ app = find_app_by_notify_sock(sock);
+ if (!app) {
+ goto close_socket;
+ }
+
+ iter.iter.node = &app->notify_sock_n.node;
+
+ /*
+ * Whatever happens here either we fail or succeed, in both cases we have
+ * to close the socket after a grace period to continue to the call RCU
+ * here. If the deletion is successful, the application is not visible
+ * anymore by other threads and is it fails it means that it was already
+ * deleted from the hash table so either way we just have to close the
+ * socket.
+ */
+ (void) lttng_ht_del(ust_app_ht_by_notify_sock, &iter);
+
+close_socket:
+ rcu_read_unlock();
+
+ /*
+ * Close socket after a grace period to avoid for the socket to be reused
+ * before the application object is freed creating potential race between
+ * threads trying to add unique in the global hash table.
+ */
+ if (!err_enomem) {
+ call_rcu(&obj->head, close_notify_sock_rcu);
+ }
+}
projects / lttng-tools.git / blobdiff