Re: [U-Boot] [PATCH V2] hush: fix some quoted variable expansion issues

Re: [U-Boot] [PATCH V2] hush: fix some quoted variable expansion issues

[Tom Rini]

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On Sat, Mar 01, 2014 at 09:26:26PM -0700, Stephen Warren wrote:
> On 03/01/2014 05:10 PM, Simon Glass wrote:
> > Hi Stephen,
> > 
> > On 27 February 2014 22:00, Stephen Warren <swarren@wwwdotorg.org
> > <mailto:swarren@wwwdotorg.org>> wrote:
> > 
> >     The following shell command fails:
> > 
> >     if test -z "$x"; then echo "zero"; else echo "non-zero"; fi
> > 
> >     (assuming $x does not exist, it prints "non-zero" rather than "zero").
> > 
> >     ... since "$x" expands to nothing, and the argument is completely
> >     dropped, causing too few to be passed to -z, causing cmd_test() to
> >     error out early.
> > 
> >     This is because when variable expansions are processed by make_string(),
> >     the expanded results are concatenated back into a new string. However,
> >     no quoting is applied when doing so, so any empty variables simply don't
> >     generate any parameter when the combined string is parsed again.
> > 
> >     Fix this by explicitly replacing quoting any argument that was
> >     originally
> >     quoted when re-generating a string from the already-parsed argument
> >     list.
> > 
> >     This also fixes loss of whitespace in commands such as:
> > 
> >     setenv space " "
> >     setenv var " 1${space}${space} 2 "
> >     echo ">>${var}<<"
> > 
> > 
> > Is there an upstream still for hush, or are we so far away that it
> > doesn't matter? If there is, was this bug fixed there?
> 
> Well, the comments at the head of the file say it came from Busybox, but
> it's obviously diverged massively since it was imported:
> 
> $ wc -l busybox/shell/hush.c u-boot/common/hush.c
> 9156 busybox/shell/hush.c
> 3682 u-boot/common/hush.c
> $ diff -u busybox/shell/hush.c u-boot/common/hush.c|wc -l
> 12264
> 
> Also, the function this patch touches doesn't seem to exist under that
> name any more. From a quick look at the source, I couldn't tell what the
> equivalent is.
> 
> Perhaps replaying patches to that file in Busybox since the fork might
> be more useful.
> 
> A quick Google search for "hush" or "hush shell" doesn't seem to yield
> any other alternative upstreams.

For reference the patch is at http://patchwork.ozlabs.org/patch/325023/

Since U-Boot and Barebox are the only users of this particular hush
fork, and from G+ they also have this problem, maybe we can use this as
a starting point of a little more friendly coordination between the
projects?

-- 
Tom

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