AC_CHECK_PROG and 'test -x'

[Sander Niemeijer]

Hi all,

I have send the e-mail below more then a month ago to the bug-autoconf 
list without receiving any reaction.
The problem is still there that _AS_TEST_PREPARE as used by 
AS_EXECUTABLE_P, as used by AC_CHECK_PROG, is only using 'test -f', 
which only tests whether we have a file at hand. I am still missing the 
test for executability of the file with a 'test -x' (currently I have a 
problem on a system of a user that has an 'install' script without 
execution permission as first entry in the list of possible 'install' 
executables. Of course the user could circumvent the problem himself by 
reordering his PATH entries, but I would rather have configure deal 
with this).

Furthermore, I figured out that the proposal I made in the previous 
e-mail wouldn't work, since a 'test -x' without a 'test -f' would also 
allow directories with executable permissions to be used for a 
AC_CHECK_PROG.
So the check that should actually be done by AC_CHECK_PROG is a 'test 
-f <file> && test -x <file>'

So here are some questions I hope people on this list can give me an 
answer to:

1) Is AS_EXECUTABLE_P only intended to test for executability in 
general or for executability of a *file*? (this determines whether 
AS_EXECUTABLE_P should only perform a 'test -x' or also a 'test -f')

2) Is 'test -x' portable (i.e. is the -x option available on all 
systems for which autoconf is supported, and does the -x option have 
the same semantics on all these systems).

3) Is anyone one the list willing to implement any changes to support 
'test -x' for AC_CHECK_PROG, or do I have to device a patch myself 
(since we are now in the holiday season I may have some time to do this 
myself :-)

Greetings,
Sander Niemeijer

On Tuesday, November 19, 2002, at 05:20 PM, Sander Niemeijer wrote:

> It seems that in the _AS_TEST_PREPARE part of the m4sugar/m4sh.m4 
> file, as_executable_p is not set to 'test -x' if this can be done. An 
> old seemingly 'buggy' version was renamed to _AS_BROKEN_TEST_PREPARE.
> I was wondering whether the old test can't be rewritten to test 
> executability of '/bin/sh' (which is always available and executable, 
> right?). This would turn it into something like:
>
> ---
> m4_defun([_AS_TEST_PREPARE],
> [if test -x /bin/sh >/dev/null 2>&1; then
>   as_executable_p="test -x"
> elif test -f /bin/sh >/dev/null 2>&1; then
>   as_executable_p="test -f"
> else
>   AS_ERROR([cannot check whether a file is executable on this system])
> fi
> ])# _AS_TEST_PREPARE
> ---
>
> Anybody got any idea whether this is a portable solution?
>
> Regards,
> Sander