Bug#648148: autopkgtest: Support running as user

[Jakub Wilk]

* Martin Pitt <martin.pitt at ubuntu.com>, 2011-11-09, 08:50:
>-	if 'needs-root' not in t.restriction_names and opts.user is not None:
>+	if 'needs-root' not in t.restriction_names and opts.user:
> 		tfl = ['su',opts.user,'-c',tf]
> 		tmpdir = '%s%s-tmpdir' % (testbed.scratch.read(True), t.what)
> 		script = 'rm -rf -- "$1"; mkdir -- "$1"'

After applying this hunk, TMPDIR variable is no longer exposed to test 
scripts, even when adt-run is run as root.

(Setting TMPDIR was a mistake in the first place IMHO. This variable in 
POSIX has completely different semantics. Running a scripts that relied 
on the feature outside adt-run might lead to security holes.)

-- 
Jakub Wilk