goto error_free_pipe;
}
+ urcu_ref_init(<a->ref);
+
lta->event_notifier_group.event_pipe = event_notifier_event_source_pipe;
lta->ppid = msg->ppid;
return ret;
}
-/*
- * Unregister app by removing it from the global traceable app list and freeing
- * the data struct.
- *
- * The socket is already closed at this point so no close to sock.
- */
-void ust_app_unregister(int sock)
+static void ust_app_unregister(struct ust_app *app)
{
- struct ust_app *lta;
- struct lttng_ht_node_ulong *node;
- struct lttng_ht_iter ust_app_sock_iter;
+ int ret;
struct lttng_ht_iter iter;
struct ust_app_session *ua_sess;
- int ret;
rcu_read_lock();
- /* Get the node reference for a call_rcu */
- lttng_ht_lookup(ust_app_ht_by_sock, (void *)((unsigned long) sock), &ust_app_sock_iter);
- node = lttng_ht_iter_get_node_ulong(&ust_app_sock_iter);
- assert(node);
-
- lta = caa_container_of(node, struct ust_app, sock_n);
- DBG("PID %d unregistering with sock %d", lta->pid, sock);
-
/*
* For per-PID buffers, perform "push metadata" and flush all
* application streams before removing app from hash tables,
* ensuring proper behavior of data_pending check.
* Remove sessions so they are not visible during deletion.
*/
- cds_lfht_for_each_entry(lta->sessions->ht, &iter.iter, ua_sess,
+ cds_lfht_for_each_entry(app->sessions->ht, &iter.iter, ua_sess,
node.node) {
struct ust_registry_session *registry;
- ret = lttng_ht_del(lta->sessions, &iter);
+ ret = lttng_ht_del(app->sessions, &iter);
if (ret) {
/* The session was already removed so scheduled for teardown. */
continue;
}
if (ua_sess->buffer_type == LTTNG_BUFFER_PER_PID) {
- (void) ust_app_flush_app_session(lta, ua_sess);
+ (void) ust_app_flush_app_session(app, ua_sess);
}
/*
(void) close_metadata(registry, ua_sess->consumer);
}
}
- cds_list_add(&ua_sess->teardown_node, <a->teardown_head);
+ cds_list_add(&ua_sess->teardown_node, &app->teardown_head);
pthread_mutex_unlock(&ua_sess->lock);
}
- /* Remove application from PID hash table */
- ret = lttng_ht_del(ust_app_ht_by_sock, &ust_app_sock_iter);
- assert(!ret);
-
/*
* 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
* apps_notify_thread.
*/
- iter.iter.node = <a->notify_sock_n.node;
+ iter.iter.node = &app->notify_sock_n.node;
(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 replace during app registration because the PID can be reassigned by
- * the OS.
- */
- iter.iter.node = <a->pid_n.node;
+ iter.iter.node = &app->pid_n.node;
ret = lttng_ht_del(ust_app_ht, &iter);
if (ret) {
- DBG3("Unregister app by PID %d failed. This can happen on pid reuse",
- lta->pid);
+ WARN("Unregister app by PID %d failed", app->pid);
}
- /* Free memory */
- call_rcu(<a->pid_n.head, delete_ust_app_rcu);
+ rcu_read_unlock();
+}
+
+/*
+ * Unregister app by removing it from the global traceable app list and freeing
+ * the data struct.
+ *
+ * The socket is already closed at this point, so there is no need to close it.
+ */
+void ust_app_unregister_by_socket(int sock)
+{
+ struct ust_app *app;
+ struct lttng_ht_node_ulong *node;
+ struct lttng_ht_iter ust_app_sock_iter;
+ int ret;
+
+ rcu_read_lock();
+
+ /* Get the node reference for a call_rcu */
+ lttng_ht_lookup(ust_app_ht_by_sock, (void *)((unsigned long) sock), &ust_app_sock_iter);
+ node = lttng_ht_iter_get_node_ulong(&ust_app_sock_iter);
+ assert(node);
+
+ app = caa_container_of(node, struct ust_app, sock_n);
+
+ DBG("PID %d unregistering with sock %d", app->pid, sock);
+ /* Remove application from socket hash table */
+ ret = lttng_ht_del(ust_app_ht_by_sock, &ust_app_sock_iter);
+ assert(!ret);
+
+ /*
+ * The socket is closed: release its reference to the application
+ * to trigger its eventual teardown.
+ */
+ ust_app_put(app);
rcu_read_unlock();
- return;
}
/*
* are unregistered prior to this clean-up.
*/
assert(lttng_ht_get_count(app->token_to_event_notifier_rule_ht) == 0);
-
ust_app_notify_sock_unregister(app->notify_sock);
}
}
- if (ust_app_ht) {
- cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
- ret = lttng_ht_del(ust_app_ht, &iter);
- assert(!ret);
- call_rcu(&app->pid_n.head, delete_ust_app_rcu);
- }
- }
-
/* Cleanup socket hash table */
if (ust_app_ht_by_sock) {
cds_lfht_for_each_entry(ust_app_ht_by_sock->ht, &iter.iter, app,
sock_n.node) {
ret = lttng_ht_del(ust_app_ht_by_sock, &iter);
assert(!ret);
+
+ ust_app_put(app);
}
}
/*
* Destroy a ust app data structure and free its memory.
*/
-void ust_app_destroy(struct ust_app *app)
+static void ust_app_destroy(struct ust_app *app)
{
if (!app) {
return;
int ret;
enum lttng_error_code cmd_ret = LTTNG_OK;
struct lttng_ht_iter iter;
- struct ust_app *app;
+ struct ust_app *app = NULL;
struct ltt_ust_session *usess = session->ust_session;
assert(usess);
struct ust_app_channel *ua_chan;
struct ust_app_session *ua_sess;
struct ust_registry_session *registry;
+ bool app_reference_taken;
+
+ app_reference_taken = ust_app_get(app);
+ if (!app_reference_taken) {
+ /* Application unregistered concurrently, skip it. */
+ DBG("Could not get application reference as it is being torn down; skipping application");
+ continue;
+ }
ua_sess = lookup_session_by_app(usess, app);
if (!ua_sess) {
/* Session not associated with this app. */
+ ust_app_put(app);
+ app = NULL;
continue;
}
goto error;
}
+
registry = get_session_registry(ua_sess);
- if (!registry) {
- DBG("Application session is being torn down. Skip application.");
- continue;
- }
+ assert(registry);
/* Rotate the data channels. */
cds_lfht_for_each_entry(ua_sess->channels->ht, &chan_iter.iter,
ua_sess->consumer,
/* is_metadata_channel */ false);
if (ret < 0) {
- /* Per-PID buffer and application going away. */
- if (ret == -LTTNG_ERR_CHAN_NOT_FOUND)
- continue;
cmd_ret = LTTNG_ERR_ROTATION_FAIL_CONSUMER;
goto error;
}
ua_sess->consumer,
/* is_metadata_channel */ true);
if (ret < 0) {
- /* Per-PID buffer and application going away. */
- if (ret == -LTTNG_ERR_CHAN_NOT_FOUND)
- continue;
cmd_ret = LTTNG_ERR_ROTATION_FAIL_CONSUMER;
goto error;
}
+
+ ust_app_put(app);
+ app = NULL;
}
+
+ app = NULL;
break;
}
default:
cmd_ret = LTTNG_OK;
error:
+ ust_app_put(app);
rcu_read_unlock();
return cmd_ret;
}
rcu_read_unlock();
return ret;
}
+
+static void ust_app_release(struct urcu_ref *ref)
+{
+ struct ust_app *app = container_of(ref, struct ust_app, ref);
+
+ ust_app_unregister(app);
+ ust_app_destroy(app);
+}
+
+bool ust_app_get(struct ust_app *app)
+{
+ assert(app);
+ return urcu_ref_get_unless_zero(&app->ref);
+}
+
+void ust_app_put(struct ust_app *app)
+{
+ if (!app) {
+ return;
+ }
+
+ urcu_ref_put(&app->ref, ust_app_release);
+}
#define _LTT_UST_APP_H
#include <stdint.h>
+#include <urcu/ref.h>
#include <common/index-allocator.h>
#include <common/uuid.h>
* and a linked list is kept of all running traceable app.
*/
struct ust_app {
+ /*
+ * The lifetime of 'sock' holds a reference to the application; the
+ * application management thread will release a reference to the
+ * application if the application dies.
+ */
+ struct urcu_ref ref;
int sock;
pthread_mutex_t sock_lock; /* Protects sock protocol. */
int ust_app_register(struct ust_register_msg *msg, int sock);
int ust_app_register_done(struct ust_app *app);
int ust_app_version(struct ust_app *app);
-void ust_app_unregister(int sock);
+void ust_app_unregister_by_socket(int sock);
int ust_app_start_trace_all(struct ltt_ust_session *usess);
int ust_app_stop_trace_all(struct ltt_ust_session *usess);
int ust_app_destroy_trace_all(struct ltt_ust_session *usess);
void ust_app_notify_sock_unregister(int sock);
ssize_t ust_app_push_metadata(struct ust_registry_session *registry,
struct consumer_socket *socket, int send_zero_data);
-void ust_app_destroy(struct ust_app *app);
enum lttng_error_code ust_app_snapshot_record(
const struct ltt_ust_session *usess,
const struct consumer_output *output, int wait,
bool ust_app_supports_notifiers(const struct ust_app *app);
bool ust_app_supports_counters(const struct ust_app *app);
+bool ust_app_get(struct ust_app *app);
+void ust_app_put(struct ust_app *app);
+
#else /* HAVE_LIBLTTNG_UST_CTL */
static inline
return -ENOSYS;
}
static inline
-void ust_app_unregister(int sock)
+void ust_app_unregister_by_socket(int sock)
{
}
static inline
return 0;
}
static inline
-void ust_app_destroy(struct ust_app *app)
-{
- return;
-}
-static inline
enum lttng_error_code ust_app_snapshot_record(struct ltt_ust_session *usess,
const struct consumer_output *output, int wait, uint64_t max_stream_size)
{
return 0;
}
+static inline
+void ust_app_get(struct ust_app *app)
+{
+}
+
+static inline
+void ust_app_put(struct ust_app *app)
+{
+}
+
#endif /* HAVE_LIBLTTNG_UST_CTL */
#endif /* _LTT_UST_APP_H */
projects / lttng-tools.git / commitdiff
