From b3d4dbcbfe2986711492634c193f32db14f06a22 Mon Sep 17 00:00:00 2001
From: Phil Sutter <phil@nwl.cc>
Date: Mon, 15 Jan 2018 16:27:31 +0100
Subject: [PATCH] Fix locking if LOCKDIR does not exist

The previous conversion to using flock() missed a crucial bit of code
which tries to create LOCKDIR once in case opening the lock failed -
This patch reestablishes the old behaviour.

Reported-by: Tangchen (UVP) <tang.chen@huawei.com>
Fixes: 6a826591878db ("Use flock() for --concurrent option")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Phil Sutter <psutter@redhat.com>
---
 libebtc.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/libebtc.c b/libebtc.c
index c0ff8ccfa66db..d47424872dc51 100644
--- a/libebtc.c
+++ b/libebtc.c
@@ -143,10 +143,16 @@ int use_lockfd;
  * or -2 on any other error. */
 static int lock_file()
 {
-	int fd = open(LOCKFILE, O_CREAT, 00600);
-
-	if (fd < 0)
-		return -2;
+	int fd, try = 0;
+
+retry:
+	fd = open(LOCKFILE, O_CREAT, 00600);
+	if (fd < 0) {
+		if (try == 1 || mkdir(LOCKDIR, 00700))
+			return -2;
+		try = 1;
+		goto retry;
+	}
 	return flock(fd, LOCK_EX);
 }
 
-- 
2.21.0