From 3670f4128d9d65b56397c5b86bfcc23a69cdba3d Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Wed, 9 Sep 2015 20:36:10 +0000 Subject: [PATCH] busybox: lock: implement -n "Fail rather than wait" lock -n is similiar to flock -n. If the lock was already taken, fail with exit code = 1 and write error message to stderr. example: if ! lock -n /tmp/foo ; then echo lock exits. else echo lock was free. But is locked now. fi > lock was free. But is locked now. > lock exists. Signed-off-by: Alexander Couzens SVN-Revision: 46836 --- .../utils/busybox/patches/220-add_lock_util.patch | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/package/utils/busybox/patches/220-add_lock_util.patch b/package/utils/busybox/patches/220-add_lock_util.patch index 5c7ca26da8..9cac9e6219 100644 --- a/package/utils/busybox/patches/220-add_lock_util.patch +++ b/package/utils/busybox/patches/220-add_lock_util.patch @@ -35,7 +35,7 @@ lib-$(CONFIG_MICROCOM) += microcom.o --- /dev/null +++ b/miscutils/lock.c -@@ -0,0 +1,135 @@ +@@ -0,0 +1,144 @@ +/* + * Copyright (C) 2006 Felix Fietkau + * @@ -56,6 +56,7 @@ +static int unlock = 0; +static int shared = 0; +static int waitonly = 0; ++static int try_lock = 0; +static int fd; +static char *file; + @@ -65,6 +66,7 @@ + " -s Use shared locking\n" + " -u Unlock\n" + " -w Wait for the lock to become free, don't acquire lock\n" ++ " -n Don't wait for the lock to become free. Fail with exit code\n" + "\n", name); + exit(1); +} @@ -95,6 +97,7 @@ +static int do_lock(void) +{ + int pid; ++ int flags; + char pidstr[8]; + + if ((fd = open(file, O_RDWR | O_CREAT | O_EXCL, 0700)) < 0) { @@ -104,7 +107,10 @@ + } + } + -+ if (flock(fd, (shared ? LOCK_SH : LOCK_EX)) < 0) { ++ flags = shared ? LOCK_SH : LOCK_EX; ++ flags |= try_lock ? LOCK_NB : 0; ++ ++ if (flock(fd, flags) < 0) { + fprintf(stderr, "Can't lock %s\n", file); + return 1; + } @@ -156,6 +162,9 @@ + case 'u': + unlock = 1; + break; ++ case 'n': ++ try_lock = 1; ++ break; + } + } + c--; -- 2.30.2