Lttng-ctl: Expose sessiond cmd_clear_session command

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>

diff --git a/include/lttng/session.h b/include/lttng/session.h
index 599892d13508d7470f829f6c89da84b18aea6b9c..dff6b45d40dedcf09001d76c1c7124f10c5e49d9 100644 (file)
--- a/include/lttng/session.h
+++ b/include/lttng/session.h
@@ -84,6 +84,41 @@ extern int lttng_create_session_snapshot(const char *name,
 extern int lttng_create_session_live(const char *name, const char *url,
                unsigned int timer_interval);
 
+/*
+ * Clear a tracing session.
+ *
+ * Clear the data buffers and trace data.
+ *
+ * For sessions saving trace data to disk and streaming over the network to a
+ * relay daemon, the buffers content and existing stream files are cleared when
+ * the clear command is issued.
+ *
+ * For snapshot sessions (flight recorder), only the buffer content is cleared.
+ * Prior snapshots are individually recorded to disk, and are therefore
+ * untouched by this "clear" command.
+ *
+ * For live sessions streaming over network to a relay daemon, the buffers
+ * will be cleared, and the files on the relay daemon side will be cleared as
+ * well. However, any active live trace viewer currently reading an existing
+ * trace packet will be able to proceed to read that packet entirely before
+ * skipping over cleared stream data.
+ *
+ * The clear command guarantees that no trace data preceding the instant it is
+ * called will be in the resulting trace.
+ *
+ * Trace data produced from the moment it is called and when the
+ * function returned might be present in the resulting trace.
+ *
+ * Return 0 on success else a negative LTTng error code.
+ *
+ * Important error codes:
+ *    LTTNG_ERR_CLEAR_DISALLOWED_RELAY
+ *    LTTNG_ERR_CLEAR_NOT_AVAILABLE
+ *    LTTNG_ERR_CLEAR_NOT_AVAILABLE_RELAY
+ *    LTTNG_ERR_CLEAR_FAIL_CONSUMER
+*/
+extern int lttng_clear_session(const char *name);
+
 /*
  * Destroy a tracing session.
  *

diff --git a/src/common/sessiond-comm/sessiond-comm.h b/src/common/sessiond-comm/sessiond-comm.h
index 7842a2122b1165849231a3fae93c1d15a1b7b416..51f680005f5e67113b912d988cf9b7c067b8def9 100644 (file)
--- a/src/common/sessiond-comm/sessiond-comm.h
+++ b/src/common/sessiond-comm/sessiond-comm.h
@@ -100,6 +100,7 @@ enum lttcomm_sessiond_command {
        LTTNG_REGENERATE_STATEDUMP          = 42,
        LTTNG_REGISTER_TRIGGER              = 43,
        LTTNG_UNREGISTER_TRIGGER            = 44,
+       LTTNG_CLEAR_SESSION                 = 49,
 };
 
 enum lttcomm_relayd_command {

diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index 2d84aad90238904440f377eae0d945f59c0ecb20..48d7f8890c9b0184f1e08299a7122b9211fde689 100644 (file)
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -1659,6 +1659,26 @@ int lttng_create_session(const char *name, const char *url)
        return ret;
 }
 
+/*
+ * Clear the session
+ */
+int lttng_clear_session(const char *session_name)
+{
+       struct lttcomm_session_msg lsm;
+
+       if (session_name == NULL) {
+               return -LTTNG_ERR_INVALID;
+       }
+
+       memset(&lsm, 0, sizeof(lsm));
+
+       lsm.cmd_type = LTTNG_CLEAR_SESSION;
+       lttng_ctl_copy_string(lsm.session.name, session_name,
+                       sizeof(lsm.session.name));
+
+       return lttng_ctl_ask_sessiond(&lsm, NULL);
+}
+
 /*
  * Destroy session using name.
  * Returns size of returned session payload data or a negative error code.