From: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Date: Mon, 11 Feb 2019 16:24:38 +0000 (-0500)
Subject: Lttng-ctl: Expose sessiond cmd_clear_session command
X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=commitdiff_plain;h=818ea544c74e89a68bcad32744a465bfdb648569

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 599892d13..dff6b45d4 100644
--- 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/bin/lttng-sessiond/client.c b/src/bin/lttng-sessiond/client.c
index a889529a7..31ee73c88 100644
--- a/src/bin/lttng-sessiond/client.c
+++ b/src/bin/lttng-sessiond/client.c
@@ -36,6 +36,7 @@
 #include "testpoint.h"
 #include "utils.h"
 #include "manage-consumer.h"
+#include "clear.h"
 
 static bool is_root;
 
@@ -740,6 +741,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
 	case LTTNG_ROTATION_GET_INFO:
 	case LTTNG_ROTATION_SET_SCHEDULE:
 	case LTTNG_SESSION_LIST_ROTATION_SCHEDULES:
+	case LTTNG_CLEAR_SESSION:
 		need_domain = 0;
 		break;
 	default:
@@ -2000,6 +2002,14 @@ error_add_context:
 		ret = LTTNG_OK;
 		break;
 	}
+	case LTTNG_CLEAR_SESSION:
+	{
+		ret = cmd_clear_session(cmd_ctx->session);
+		if (ret != LTTNG_OK) {
+			goto error;
+		}
+		break;
+	}
 	default:
 		ret = LTTNG_ERR_UND;
 		break;
diff --git a/src/common/sessiond-comm/sessiond-comm.h b/src/common/sessiond-comm/sessiond-comm.h
index 336ebe978..f06553a7b 100644
--- a/src/common/sessiond-comm/sessiond-comm.h
+++ b/src/common/sessiond-comm/sessiond-comm.h
@@ -105,6 +105,7 @@ enum lttcomm_sessiond_command {
 	LTTNG_ROTATION_GET_INFO               = 46,
 	LTTNG_ROTATION_SET_SCHEDULE           = 47,
 	LTTNG_SESSION_LIST_ROTATION_SCHEDULES = 48,
+	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 165fef4dc..3b6423f6d 100644
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -1784,6 +1784,26 @@ 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.