Re: [PATCH nfs-utils] start-statd: use flock -x instead of -e for busybox compatibility

[Calum Mackay <calum.mackay@oracle.com>]

[-- Attachment #1.1: Type: text/plain, Size: 1736 bytes --]

On 28/02/2024 6:56 pm, Ahmad Fatoum wrote:
> busybox flock(1) only supports -x and not -e. util-linux flock(1)
> treats both -e and -x the same, documents them both in its man page,
> but lists only -x in its help output.
> 
> Referring to util-linux git, it seems both options were added between
> util-linux-2.13-pre1 and util-linux-2.13-pre2 back in 2006, so there
> should be no harm in switching over to flock -x to avoid confusing
> error output when attempting to mount a NFS on a busybox system:
> 
>    $ mount -t nfs 192.168.2.13:/home/afa/nfsroot/imx8mn-evk /mnt
>    flock: invalid option -- 'e'
>    BusyBox v1.36.0 () multi-call binary.
> 
>    Usage: flock [-sxun] FD | { FILE [-c] PROG ARGS }
> 
>    [Un]lock file descriptor, or lock FILE, run PROG
> 
>            -s      Shared lock
>            -x      Exclusive lock (default)
>            -u      Unlock FD
>            -n      Fail rather than wait
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

hi Ahmad,

Since the default is an exclusive lock, in both BusyBox and util-linux, 
might it be simpler just to run flock without that option?

best wishes,
calum.

> ---
>   utils/statd/start-statd | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/utils/statd/start-statd b/utils/statd/start-statd
> index b11a7d91a7f6..67a2f4ad8e0e 100755
> --- a/utils/statd/start-statd
> +++ b/utils/statd/start-statd
> @@ -8,7 +8,7 @@ PATH="/sbin:/usr/sbin:/bin:/usr/bin"
>   
>   # Use flock to serialize the running of this script
>   exec 9> /run/rpc.statd.lock
> -flock -e 9
> +flock -x 9
>   
>   if [ -s /run/rpc.statd.pid ] &&
>          [ "1$(cat /run/rpc.statd.pid)" -gt 1 ] &&



[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 840 bytes --]