Re: [PATCH 1/5] m4sh: fix some namespace safety issues

[Eric Blake]

On 08/25/2010 08:56 PM, Eric Blake wrote:
> On 08/25/2010 05:18 PM, Eric Blake wrote:
> > * lib/m4sugar/m4sh.m4 (_AS_SHELL_SANITIZE): Avoid problems if
> > as_myself is inherited from environment.
> > (AS_TMPDIR): Be namespace clean.
>
> Phooey. I didn't run the whole testsuite, but this patch breaks some of
> the tests, starting with 14: autoconf: subdirectories. Once I find a
> fix, I'll be pushing something shortly. :(
>
> > @@ -1618,12 +1619,13 @@ m4_define([AS_TMPDIR],
> > [# Create a (secure) tmp directory for tmp files.
> > m4_if([$2], [], [: ${TMPDIR=/tmp}])
> > {
> > - tmp=`(umask 077&& mktemp -d "m4_default([$2], [$TMPDIR])/$1XXXXXX")
> > 2>/dev/null`&&
> > - test -n "$tmp"&& test -d "$tmp"
> > + as_tmp=`(umask 077&& mktemp -d "m4_default([$2],
> > + [$TMPDIR])/$1XXXXXX") 2>/dev/null`&&
> > + test -d "$as_tmp"

Found it.  NEWS documents, and config.status relies, on $tmp being a 
safe temporary directory.  So even though it is not clean by normal 
namespace rules, it is historical baggage and part of our public API 
contract.  I'm reverting this hunk of the patch, and adding a comment in 
its place so we don't make this mistake of trying to 'fix' it again.

--
Eric Blake   address@hidden    +1-801-349-2682
Libvirt virtualization library http://libvirt.org