Problem with ash redirection changing behaviour

[Cristian Ionescu-Idbohrn]

On Wed, 2 Jun 2010, Richard Purdie wrote:

> I have an issue having recently upgraded busybox. The change that is
> causing me problems is:
>
> http://git.busybox.net/busybox/commit/?id=6a0ad2506116f4ddc3f9f617a90ba04a57eeef88
>
> which is sanity checking file descriptors before allowing redirection.
>
> A script that triggers the problem is:
>
> """
> exec 9>&0 </etc/fstab
> while read fs mnt type opts dump pass junk
> do
> 	echo $fs
> done
> exec 0>&9 9>&-
> """

That should work.

> The idea being to save stdin, read from a file and then restore stdin
> without forking.

But so should this (no forks here either, and simplier):

while read fs mnt type opts dump pass junk; do
	case $fs in
		\#*|'')
			continue
			;;
		*)
			echo $fs
			;;
	esac
done < /etc/fstab

Does the above work for you?

> This used to work but now when run as ". script" from ash

Any particular reason to 'source'?  You end up with environment
clutter:

dump=''
fs=''
junk=''
mnt=''
opts=''
pass=''
type=''

Is that intentional?


Cheers,

-- 
Cristian