X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;ds=sidebyside;f=usttrace;h=15336f638d91ab7133842d149456667b3033d162;hb=5de791bd1dae05e595ab74016f7333912f2492a8;hp=1db591f366495b14df7007a2a7ac026d6f541a70;hpb=63f16f2e575c64c94e8b6683e327e4ab31c59231;p=lttng-ust.git

diff --git a/usttrace b/usttrace
index 1db591f3..15336f63 100755
--- a/usttrace
+++ b/usttrace
@@ -87,6 +87,13 @@ then
 	mkfifo -m 0600 "$pidfilepath"
 	# Start daemon
 	$USTD --pidfile "$pidfilepath" -s "$SOCKPATH" -o "$OUTDIR" >"$OUTDIR/ustd.log" 2>&1 &
+	# ustd sets up its server socket
+	# ustd opens the pidfile, blocks because no one has opened it
+	# we open pidfile
+	# we block reading pidfile
+	# ustd writes to pidfile
+	# ustd closes pidfile
+	# we unblock reading pidfile
 	USTDPID="$(<$pidfilepath)"
 	export UST_DAEMON_SOCKET="$SOCKPATH"
 fi