X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=lttctl%2Flttctl.c;h=e77b7f38d6833f8abc2cc8dd0fba8b19b9a9c146;hb=635683d75350f395da23354a7524dfd0a1363d48;hp=7380136fc6eefcbe1e0c4bb3da3e81e80815a438;hpb=8d5607b44df5d7328c6885b29b711e97eb766f13;p=ltt-control.git

diff --git a/lttctl/lttctl.c b/lttctl/lttctl.c
index 7380136..e77b7f3 100644
--- a/lttctl/lttctl.c
+++ b/lttctl/lttctl.c
@@ -2,14 +2,26 @@
  *
  * Linux Trace Toolkit Control
  *
- * Small program that controls LTT through libltt.
- *
- * Copyright 2005 -
- * 	Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ * Small program that controls LTTng through liblttctl.
  *
  * Copyright 2008 FUJITSU
  * 	Zhao Lei <zhaolei@cn.fujitsu.com>
  * 	Gui Jianfeng <guijianfeng@cn.fujitsu.com>
+ * Copyright 2009-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #ifdef HAVE_CONFIG_H
@@ -144,6 +156,11 @@ static void show_arguments(void)
 	printf("        Set channels root path, For -w option."
 		" (ex. /mnt/debugfs/ltt)\n");
 	printf("\n");
+	printf(" Environment variables:\n");
+	printf("  LTT_DAEMON\n");
+	printf("       Complete path to the lttd binary (needs to be\n");
+	printf("       specified if different than package build prefix).\n");
+	printf("\n");
 }
 
 /*
@@ -679,10 +696,13 @@ setup_trace_fail:
 }
 
 /*
- * Start a lttd daemon to write trace datas
+ * Start a lttd daemon to write trace data
  * Dump overwrite channels on overwrite!=0
  * Dump normal(non-overwrite) channels on overwrite=0
  *
+ * When called for overwrite mode, wait for lttd to return, so we are sure that
+ * trace session teardown is not executed before lttd can grab the buffer data.
+ *
  * ret: 0 on success
  *      !0 on fail
  */
@@ -777,6 +797,16 @@ static int lttctl_daemon(int overwrite)
 	if (WEXITSTATUS(status))
 		fprintf(stderr, "lttd process running failed\n");
 
+	/*
+	 * FIXME
+	 * This is a temporary hack to ensure that the lttd daemon grabs
+	 * handles on the debugfs buffer files before we destroy the trace
+	 * session. Properly handling this will imply separating the "flush"
+	 * from the "destroy" operation at kernel-level in LTTng.
+	 */
+	if (overwrite)
+		sleep(2);
+
 	return WEXITSTATUS(status);
 }