Hi Jim, > Before embarking on changes to (or duplication of) infrastructure like > the *at functions, please tell us about your motivation. Why do you care > about whether openat may abort under unusual circumstances
The reason is so that libposix can offer openat() and getcwd() among the functions that it offers. Nothing in libposix should call chdir() without the guaranteed ability to restore the previous working directory. And nothing in libposix should call error(), since error reporting is the application's task. See <http://lists.gnu.org/archive/html/bug-gnulib/2010-12/msg00178.html> and <http://lists.gnu.org/archive/html/bug-gnulib/2010-12/msg00069.html>. My proposal to solve the problem in December was naïve. I find it good that Bastien thinks at a better one. > As I tried to explain, there does not seem to be a clean way > to solve the problem I believe the stuff with chdir() is only needed in order to handle special cases like - long directory and file names that would otherwise lead to ENAMETOOLONG, - access relative to a directory where 'cd $(pwd)' would not work, because of missing permissions in the parent directories. Therefore I believe it should be possible to propose an openat() implementation in libposix that, admittedly, cannot handle these special cases. But that would be better than nothing. And coreutils, which does not want these restrictions, would continue to use the current code for openat(). > the target systems that would benefit > from this portability improvement are mostly old and dying: not supporting > POSIX-mandated *at functions is a good sign that they are not evolving. Huh? Here's the portability state of openat(): $ ./show-portability openat libc aix-7.1.0 libc cygwin-1.7 libcygwin cygwin-1.7 libc solaris-2.10 libc solaris-2.11_2010_11 libc solaris-2.9 MISSING in aix-4.3.2 aix-5.1.0 aix-5.2.0 aix-5.3.0a aix-6.1.0 beos cygwin-1.5 freebsd-5.2.1 freebsd-6.0 freebsd-6.4 glibc-2.3.6 hpux-10.20 hpux-11.00 hpux-11.11 hpux-11.23 hpux-11.31 interix-3.5 irix-5.3 irix-6.5 macosx-10.3 macosx-10.4 macosx-10.5 mingw netbsd-3.0 netbsd-5.0.1 netbsd-5.0 nsk-G06 openbsd-3.8 osf1-4.0d osf1-5.1a pips solaris-2.4 solaris-2.5.1 solaris-2.6 solaris-2.7 solaris-2.8 Also, FreeBSD >= 8.0 has it. But OpenBSD and NetBSD do not have it. [1][2] I wouldn't say that MacOS X, OpenBSD, and NetBSD are "not evolving". Bruno [1] http://www.openbsd.org/cgi-bin/cvsweb/src/sys/sys/fcntl.h?rev=HEAD [2] http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/sys/fcntl.h?rev=HEAD&content-type=text/x-cvsweb-markup&only_with_tag=MAIN
