Hi Jim,
Getting back to this issue from last Monday:
> > If we fix Eric's typo, REPLACE_GETCWD will come out as 0 on OpenBSD and
> > NetBSD.
>
> Do you know how that happens, given the corrected code?
It's because of the details in m4/getcwd-abort-bug.m4.
> The part that is surprising is that they would have
> $gl_cv_func_getcwd_path_max = yes.
> That would mean that getcwd (NULL, 0) can succeed when called
> from a directory whose name is longer than PATH_MAX.
No, it doesn't succeed. But the logic at the end of m4/getcwd-abort-bug.m4
claims that this failure was a success.
> > Can packages that use gnulib's getcwd() module - including coreutils -
> > expect that in normal conditions (no EPERM anywhere)
> > mkdir ("subdir1", 0700);
> > chdir ("subdir1");
> > mkdir ("subdir2", 0700);
> > chdir ("subdir2");
> > ...
> > mkdir ("subdir1000", 0700);
> > chdir ("subdir1000");
> > dir = getcwd (NULL, 0);
> > produces a non-NULL dir (longer than PATH_MAX) ?
>
> Yes, assuming that nothing else goes wrong.
Thanks, this is clear.
> > So what you are saying is that the unit test and the documentation are
> > correct, and only the getcwd*.m4 files need to be changed so as to activate
> > the replacement in lib/getcwd.c. This replacement will first call the
> > system's getcwd() function, so as to handle file names shorter than PATH_MAX
> > with inaccessible parents.
> >
> > Is that what you mean?
>
> Yes.
OK, clear.
> I think Eric proposed some POSIX wording change that would
> allow gnulib's getcwd to be considered compliant.
OK, I try to avoid making a firm claim about what POSIX says in this area.
I'm applying this fix.
2011-11-27 Bruno Haible <br...@clisp.org>
getcwd: Fix bug from 2011-08-17.
* m4/getcwd.m4 (gl_FUNC_GETCWD): Set REPLACE_GETCWD to 1 only on
platforms that need it.
* m4/getcwd-abort-bug.m4 (gl_FUNC_GETCWD_ABORT_BUG): Consider a return
code of 4 to be a failure, not a success. This ensures that
REPLACE_GETCWD becomes 1 on OpenBSD 4.9 and NetBSD 5.1.
--- m4/getcwd-abort-bug.m4.orig Mon Nov 28 00:00:21 2011
+++ m4/getcwd-abort-bug.m4 Sun Nov 27 23:50:37 2011
@@ -1,4 +1,4 @@
-# serial 6
+# serial 7
# Determine whether getcwd aborts when the length of the working directory
# name is unusually large. Any length between 4k and 16k trigger the bug
# when using glibc-2.4.90-9 or older.
@@ -91,7 +91,8 @@
results in a failed assertion. */
cwd = getcwd (NULL, 0);
if (cwd == NULL)
- fail = 4; /* getcwd failed. This is ok, and expected. */
+ fail = 4; /* getcwd failed: it refuses to return a string longer
+ than PATH_MAX. */
free (cwd);
/* Call rmdir first, in case the above chdir failed. */
@@ -110,11 +111,18 @@
}
]])],
[gl_cv_func_getcwd_abort_bug=no],
- dnl A "regular" nonzero return does not indicate this bug.
- dnl An abort will provoke an exit code of something like 134 (128 + 6).
- [test $? -gt 128 \
- && gl_cv_func_getcwd_abort_bug=yes \
- || gl_cv_func_getcwd_abort_bug=no],
+ [dnl An abort will provoke an exit code of something like 134 (128 + 6).
+ dnl An exit code of 4 can also occur (in OpenBSD 4.9, NetBSD 5.1 for
+ dnl example): getcwd (NULL, 0) fails rather than returning a string
+ dnl longer than PATH_MAX. This may be POSIX compliant (in some
+ dnl interpretations of POSIX). But gnulib's getcwd module wants to
+ dnl provide a non-NULL value in this case.
+ ret=$?
+ if test $ret -ge 128 || test $ret = 4; then
+ gl_cv_func_getcwd_abort_bug=yes
+ else
+ gl_cv_func_getcwd_abort_bug=no
+ fi],
[gl_cv_func_getcwd_abort_bug=yes])
])
AS_IF([test $gl_cv_func_getcwd_abort_bug = yes], [$1], [$2])
--- m4/getcwd.m4.orig Mon Nov 28 00:00:21 2011
+++ m4/getcwd.m4 Sun Nov 27 23:37:22 2011
@@ -6,7 +6,7 @@
# with or without modifications, as long as this notice is preserved.
# Written by Paul Eggert.
-# serial 10
+# serial 11
AC_DEFUN([gl_FUNC_GETCWD_NULL],
[
@@ -139,12 +139,12 @@
;;
esac
- case
$gl_cv_func_getcwd_null,$gl_cv_func_getcwd_posix_signature$gl_cv_func_getcwd_path_max,$gl_abort_bug
in
- *yes,yes,yes,no) ;;
- *)
- dnl Full replacement lib/getcwd.c, overrides LGPL replacement.
- REPLACE_GETCWD=1;;
- esac
+ if { case "$gl_cv_func_getcwd_null" in *yes) false;; *) true;; esac; } \
+ || test $gl_cv_func_getcwd_posix_signature != yes \
+ || test "$gl_cv_func_getcwd_path_max" != yes \
+ || test $gl_abort_bug = yes; then
+ REPLACE_GETCWD=1
+ fi
])
# Prerequisites of lib/getcwd.c, when full replacement is in effect.
--
In memoriam George Moscone <http://en.wikipedia.org/wiki/George_Moscone>
