AC_CHECK_PROG and 'test -x' (again)

[Sander Niemeijer]

Hi all,

In December 2002 I sent the message below to the list, but got no reply 
from the autoconf maintainers because they were on holiday as I was 
told. I did get a reply from Eric Sunshine stating:

ES> Unfortunately, `test -x' is not portable.  I regularly still use 
platforms
ES> on which the `test' program does not recognize the `-x' switch.

I was wondering if anyone is currently reading the list who can help me 
shed some more light on this issue.

I'm still looking for a solution to the problem I have as a result of 
autoconf not using 'test -x' but 'test -f' to test for executability. 
If possible then I would really like to see a reappearance of 'test -x' 
for the platforms that support a 'test -x'.

Regards,
Sander

Begin forwarded message:

> From: Sander Niemeijer <address@hidden>
> Date: maa dec 23, 2002  15:57:35 Europe/Amsterdam
> To: address@hidden, address@hidden
> Subject: AC_CHECK_PROG and 'test -x'
>
> 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