Docs: document the format of the lttng_session path member

[lttng-tools.git] / include / lttng / session.h

diff --git a/include/lttng/session.h b/include/lttng/session.h
index 2c9b842d4c693be23478c30d2e40c33e4d22d623..e626b00814ea1fec171a7d508d8d3495c0ea950a 100644 (file)
--- a/include/lttng/session.h
+++ b/include/lttng/session.h
@@ -32,8 +32,16 @@ extern "C" {
  */
 #define LTTNG_SESSION_PADDING1             12
 struct lttng_session {
-       char name[NAME_MAX];
-       /* The path where traces are written */
+       char name[LTTNG_NAME_MAX];
+       /*
+        * Human-readable representation of the trace's destination.
+        * In the case of a local tracing session, a path is provided:
+        *     /path/to/the/output
+        *
+        * In the case of a remote (network) tracing session, the string has
+        * the following format:
+        *     net://hostname/path:ctrl_port [data: data_port]
+        */
        char path[PATH_MAX];
        uint32_t enabled;       /* enabled/started: 1, disabled/stopped: 0 */
        uint32_t snapshot_mode;
@@ -76,8 +84,7 @@ extern int lttng_create_session_snapshot(const char *name,
  * indexes are sent and metadata is checked for each packet.
  *
  * Name can't be NULL. If no URL is given, the default is to send the data to
- * net://127.0.0.1. The timer_interval is in usec and by default set to 1000000
- * (1 second).
+ * net://127.0.0.1. The timer_interval is in usec.
  *
  * Return 0 on success else a negative LTTng error code.
  */
@@ -90,12 +97,25 @@ extern int lttng_create_session_live(const char *name, const char *url,
  * The session will not be usable, tracing will be stopped thus buffers will be
  * flushed.
  *
+ * This call will wait for data availability for each domain of the session,
+ * which can take an arbitrary amount of time. However, when returning the
+ * tracing data is guaranteed to be ready to be read and analyzed.
+ *
+ * lttng_destroy_session_no_wait() may be used if such a guarantee is not
+ * needed.
+ *
  * The name can't be NULL here.
  *
  * Return 0 on success else a negative LTTng error code.
  */
 extern int lttng_destroy_session(const char *name);
 
+/*
+ * Behaves exactly like lttng_destroy_session but does not wait for data
+ * availability.
+ */
+extern int lttng_destroy_session_no_wait(const char *name);
+
 /*
  * List all the tracing sessions.
  *
@@ -104,6 +124,51 @@ extern int lttng_destroy_session(const char *name);
  */
 extern int lttng_list_sessions(struct lttng_session **sessions);
 
+/*
+ * Set the shared memory path for a session.
+ *
+ * Sets the (optional) file system path where shared memory buffers will
+ * be created for the session. This is useful for buffer extraction on
+ * crash, when used with filesystems like pramfs.
+ *
+ * Return 0 on success else a negative LTTng error code.
+ */
+extern int lttng_set_session_shm_path(const char *session_name,
+               const char *shm_path);
+
+/*
+ * Add PID to session tracker.
+ *
+ * A pid argument >= 0 adds the PID to the session tracker.
+ * A pid argument of -1 means "track all PIDs".
+ *
+ * Return 0 on success else a negative LTTng error code.
+ */
+extern int lttng_track_pid(struct lttng_handle *handle, int pid);
+
+/*
+ * Remove PID from session tracker.
+ *
+ * A pid argument >= 0 removes the PID from the session tracker.
+ * A pid argument of -1 means "untrack all PIDs".
+ *
+ * Return 0 on success else a negative LTTng error code.
+ */
+extern int lttng_untrack_pid(struct lttng_handle *handle, int pid);
+
+/*
+ * List PIDs in the tracker.
+ *
+ * enabled is set to whether the PID tracker is enabled.
+ * pids is set to an allocated array of PIDs currently tracked. On
+ * success, pids must be freed by the caller.
+ * nr_pids is set to the number of entries contained by the pids array.
+ *
+ * Returns 0 on success, else a negative LTTng error code.
+ */
+extern int lttng_list_tracker_pids(struct lttng_handle *handle,
+               int *enabled, int32_t **pids, size_t *nr_pids);
+
 #ifdef __cplusplus
 }
 #endif