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| author | Felix Fietkau <nbd@openwrt.org> | 2015-09-09 20:36:10 +0000 |
|---|---|---|
| committer | Felix Fietkau <nbd@openwrt.org> | 2015-09-09 20:36:10 +0000 |
| commit | 3670f4128d9d65b56397c5b86bfcc23a69cdba3d (patch) | |
| tree | dd1015dcfc5fdf622b6034acd9efa1f38c8a3d56 /package/utils | |
| parent | 5fcafa319d25ca79638e7d705cc4fd097b8bf33b (diff) | |
| download | mtk-20170518-3670f4128d9d65b56397c5b86bfcc23a69cdba3d.zip mtk-20170518-3670f4128d9d65b56397c5b86bfcc23a69cdba3d.tar.gz mtk-20170518-3670f4128d9d65b56397c5b86bfcc23a69cdba3d.tar.bz2 | |
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 <lynxis@fe80.eu>
SVN-Revision: 46836
Diffstat (limited to 'package/utils')
| -rw-r--r-- | package/utils/busybox/patches/220-add_lock_util.patch | 13 |
1 files 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 5c7ca26..9cac9e6 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 <nbd@openwrt.org> + * @@ -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--; |