Add locking for all session data structure

[lttng-tools.git] / ltt-sessiond / session.h

diff --git a/ltt-sessiond/session.h b/ltt-sessiond/session.h
index 11f9b9ace8986b0366e046d5787a7803fa38180c..9eaa1c535e783897f0ed0ce90bf806b89f7e5e30 100644 (file)
--- a/ltt-sessiond/session.h
+++ b/ltt-sessiond/session.h
@@ -20,41 +20,57 @@
 #define _LTT_SESSION_H
 
 #include <lttng/lttng.h>
-#include <uuid/uuid.h>
+#include <urcu/list.h>
 
 /*
- * FIXME: create a cmd_context structure to pass this kind of
- * information around as parameter. Will facilitate multithreaded design
- * later.
+ * Tracing session list
+ *
+ * Statically declared in session.c and can be accessed by using
+ * get_session_list() function that returns the pointer to the list.
  */
-extern struct ltt_session *current_session;
-
-/* Global session list */
 struct ltt_session_list {
+       /*
+        * This lock protects any read/write access to the list and count (which is
+        * basically the list size). All public functions in session.c acquire this
+        * lock and release it before returning. If none of those functions are
+        * used, the lock MUST be acquired in order to iterate or/and do any
+        * actions on that list.
+        */
+       pthread_mutex_t lock;
+       /*
+        * Number of element in the list.
+        */
+       unsigned int count;
        struct cds_list_head head;
 };
 
-/* ltt-session - This data structure contains information needed
- * to identify a tracing session for both LTTng and UST.
+/*
+ * This data structure contains information needed to identify a tracing
+ * session for both LTTng and UST.
  */
 struct ltt_session {
        char *name;
-       struct cds_list_head list;
-       uuid_t uuid;
+       char *path;
+       struct ltt_kernel_session *kernel_session;
        struct cds_list_head ust_traces;
-       struct cds_list_head kernel_traces;
        unsigned int ust_trace_count;
-       unsigned int kern_trace_count;
-       pid_t ust_consumer;
-       pid_t kernel_consumer;
+       /*
+        * Protect any read/write on this session data structure. This lock must be
+        * acquired *before* using any public functions declared below. Use
+        * lock_session() and unlock_session() for that.
+        */
+       pthread_mutex_t lock;
+       struct cds_list_head list;
 };
 
 /* Prototypes */
-int create_session(char *name, uuid_t *session_id);
-int destroy_session(uuid_t *uuid);
-void get_lttng_session(struct lttng_session *lt);
-struct ltt_session *find_session_by_uuid(uuid_t session_id);
+int create_session(char *name, char *path);
+int destroy_session(char *name);
+void get_lttng_session(struct lttng_session *sessions);
+void lock_session(struct ltt_session *session);
+void unlock_session(struct ltt_session *session);
 struct ltt_session *find_session_by_name(char *name);
 unsigned int get_session_count(void);
+struct ltt_session_list *get_session_list(void);
 
 #endif /* _LTT_SESSION_H */