trackers: support tracking feature

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

diff --git a/include/lttng/session.h b/include/lttng/session.h
index 395df32450889d806aa0efd805a7a2cd67f4c219..06d4f8b9d51a4f5bea02dfb2fa0e0712f7bc945c 100644 (file)
--- a/include/lttng/session.h
+++ b/include/lttng/session.h
@@ -23,6 +23,31 @@
 extern "C" {
 #endif
 
+#include <lttng/constant.h>
+
+enum lttng_tracker_type {
+       LTTNG_TRACKER_PID = 0,
+       LTTNG_TRACKER_VPID = 1,
+       LTTNG_TRACKER_UID = 2,
+       LTTNG_TRACKER_GID = 3,
+       LTTNG_TRACKER_VUID = 4,
+       LTTNG_TRACKER_VGID = 5,
+};
+
+enum lttng_tracker_id_type {
+       LTTNG_ID_UNKNOWN = -1,
+       LTTNG_ID_ALL = 0,
+       LTTNG_ID_VALUE = 1,
+       LTTNG_ID_STRING = 2,
+};
+
+struct lttng_tracker_id {
+       enum lttng_tracker_id_type type;
+       int value;
+       char *string;
+};
+
+struct lttng_handle;
 struct lttng_session_descriptor;
 struct lttng_destruction_handle;
 
@@ -34,7 +59,7 @@ struct lttng_destruction_handle;
  *
  * The structures should be initialized to zero before use.
  */
-#define LTTNG_SESSION_PADDING1             12
+#define LTTNG_SESSION_PADDING1             8
 struct lttng_session {
        char name[LTTNG_NAME_MAX];
        /*
@@ -51,7 +76,29 @@ struct lttng_session {
        uint32_t snapshot_mode;
        unsigned int live_timer_interval;       /* usec */
 
+       /*
+        * End of public attributes.
+        * The remaining fields are used to deal with ABI management concerns.
+        */
+
+       /*
+        * 32-bit architectures are already naturally aligned on 4 bytes after
+        * 'live_timer_interval'. However, the offset does not result in a
+        * natural alignment on 64-bit architectures. Adding 4 bytes of
+        * padding here results in an aligned offset after 'alignement_padding'
+        * for both bitnesses.
+        *
+        * This was added since not all compilers appear to align unions in the
+        * same way. Some (e.g. MSVC) do not seem to impose an alignement
+        * constraint while others (e.g. gcc, clang, icc) seem to align it to
+        * ensure 'ptr' is naturally aligned.
+        */
+       char alignment_padding[4];
        union {
+               /*
+                * Ensure the 'extended' union has the same size for both
+                * 32-bit and 64-bit builds.
+                */
                char padding[LTTNG_SESSION_PADDING1];
                void *ptr;
        } extended;
@@ -141,7 +188,7 @@ extern int lttng_destroy_session(const char *name);
  * an lttng_destruction_handle which can be used to wait for the completion
  * of the session's destruction. The lttng_destroy_handle can also be used
  * obtain the status and archive location of any implicit session
- * rotation that may have occured during the session's destruction.
+ * rotation that may have occurred during the session's destruction.
  *
  * Returns LTTNG_OK on success. The returned handle is owned by the caller
  * and must be free'd using lttng_destruction_handle_destroy().
@@ -192,6 +239,46 @@ extern enum lttng_error_code lttng_session_get_creation_time(
 extern int lttng_set_session_shm_path(const char *session_name,
                const char *shm_path);
 
+/*
+ * Add ID to session tracker.
+ *
+ * tracker_type is the type of tracker.
+ * id the id to track.
+ *
+ * Return 0 on success else a negative LTTng error code.
+ */
+extern int lttng_track_id(struct lttng_handle *handle,
+               enum lttng_tracker_type tracker_type,
+               const struct lttng_tracker_id *id);
+
+/*
+ * Remove ID from session tracker.
+ *
+ * tracker_type is the type of tracker.
+ * id the id to untrack.
+ *
+ * Return 0 on success else a negative LTTng error code.
+ */
+extern int lttng_untrack_id(struct lttng_handle *handle,
+               enum lttng_tracker_type tracker_type,
+               const struct lttng_tracker_id *id);
+
+/*
+ * List IDs in the tracker.
+ *
+ * tracker_type is the type of tracker.
+ * ids is set to an allocated array of IDs currently tracked. On
+ * success, ids and the strings it contains must be freed by the
+ * caller.
+ * nr_ids is set to the number of entries contained by the ids array.
+ *
+ * Returns 0 on success, else a negative LTTng error code.
+ */
+extern int lttng_list_tracker_ids(struct lttng_handle *handle,
+               enum lttng_tracker_type tracker_type,
+               struct lttng_tracker_id **ids,
+               size_t *nr_ids);
+
 /*
  * Add PID to session tracker.
  *