On 5/29/26 17:29, Bruno Haible via Discussion list for automake wrote:
'trap' commands in shell scripts present a dilemma:
- If we use double-quotes to delimit the command
trap "rmdir '$lockdir'; exit 1" 1 2 15
we get undefined behaviour if $lockdir contains a single-quote,
and also some backslashes might be needed here and there, for
quoting.
Can we simply ensure that $lockdir will never contain a single-quote?
[...]
Here's a proposed patch.
I agree with Jan Engelhardt that evaluating $lockdir when the trap is
set is preferable to evaluating it when the trap is hit, but this means
that there is no way around expanding $lockdir in the argument to trap.
I posit that a better solution would be to add a test that our
assumptions hold to configure and bail out early on in a weird
environment that would do things like putting a single quote into
$lockdir. Maybe packages using automake should refuse to build in
directories with absolute full names containing quote marks?
Something like: (in the generated configure)
case `pwd` in
*[\'\"]*)
echo "ERROR: cannot build reliably in a location named with quote marks"
exit 1
;;
esac
A similar check for the source tree location could also be appropriate.
-- Jacob
