Fix: sessiond: sessiond and agent deadlock on destroy

[lttng-tools.git] / src / bin / lttng-sessiond / session.h

diff --git a/src/bin/lttng-sessiond/session.h b/src/bin/lttng-sessiond/session.h
index cd0f99968a897df40c059669d8200a303003e52a..0144ca6ff9bd9fdd5510f7e940aa2b184a97cbe8 100644 (file)
--- a/src/bin/lttng-sessiond/session.h
+++ b/src/bin/lttng-sessiond/session.h
@@ -75,7 +75,10 @@ struct ltt_session_list {
 struct ltt_session {
        char name[NAME_MAX];
        bool has_auto_generated_name;
+       bool name_contains_creation_time;
        char hostname[HOST_NAME_MAX]; /* Local hostname. */
+       /* Path of the last closed chunk. */
+       char last_chunk_path[LTTNG_PATH_MAX];
        time_t creation_time;
        struct ltt_kernel_session *kernel_session;
        struct ltt_ust_session *ust_session;
@@ -188,13 +191,22 @@ struct ltt_session {
        char *base_path;
 };
 
-/* Prototypes */
 enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
-               const char *base_path, struct ltt_session **out_session);
+               struct ltt_session **out_session);
 void session_lock(struct ltt_session *session);
+void session_unlock(struct ltt_session *session);
+
+/*
+ * The session list lock covers more ground than its name implies. While
+ * it does protect against concurent mutations of the session list, it is
+ * also used as a multi-session lock when synchronizing newly-registered
+ * 'user space tracer' and 'agent' applications.
+ *
+ * In other words, it prevents session configurations from changing while they
+ * are being transmitted to the various applications.
+ */
 void session_lock_list(void);
 int session_trylock_list(void);
-void session_unlock(struct ltt_session *session);
 void session_unlock_list(void);
 
 void session_destroy(struct ltt_session *session);
@@ -250,7 +262,8 @@ int session_set_trace_chunk(struct ltt_session *session,
  */
 int session_close_trace_chunk(const struct ltt_session *session,
                struct lttng_trace_chunk *trace_chunk,
-               const enum lttng_trace_chunk_command_type *close_command);
+               const enum lttng_trace_chunk_command_type *close_command,
+               char *path);
 
 bool session_output_supports_trace_chunks(const struct ltt_session *session);