openat minor cleanups

[Paul Eggert]

I installed this minor cleanup for openat.

For the FIXME, Solaris 9 actually defines AT_FDCWD to be 0xffd19553
but I think this is a bug in Solaris, since this means AT_FDCWD is of
type 'unsigned int' on all Solaris platforms, but it should be of type
'int'.  So I used the equivalent 32-bit 'int' value instead.

2004-12-02  Paul Eggert  <address@hidden>

        * lib/openat.c: Include "openat.h" before other include files.
        Include "exitfail.h".
        (openat): Remove #undef; no longer needed now that we include openat.h
        first.
        (rpl_openat): Add comment about mode_t promotion.  Simplify
        code a bit by moving initializations around.  Use exit_failure
        rather than EXIT_FAILURE.
        * lib/openat.h: Add copyright and authorship notice.
        (AT_FDCWD): Use the same value Solaris 9 uses, except of type
        'int' not 'unsigned int'.
        * m4/openat.m4: Add copyright notice.
        (gl_FUNC_OPENAT): Require gl_USE_SYSTEM_EXTENSIONS, since Solaris
        requires __EXTENSIONS__ to be defined when compiling pedantically,
        if you want AT_FDCWD.

Index: lib/openat.c
===================================================================
RCS file: /fetish/cu/lib/openat.c,v
retrieving revision 1.3
diff -p -u -r1.3 openat.c
--- lib/openat.c        28 Nov 2004 22:41:57 -0000      1.3
+++ lib/openat.c        3 Dec 2004 06:43:15 -0000
@@ -19,10 +19,7 @@
 
 #include <config.h>
 
-/* Disable the definition of openat to rpl_openat (from config.h) in this
-   file.  Otherwise, we'd get conflicting prototypes for rpl_openat on
-   most systems.  */
-#undef openat
+#include "openat.h"
 
 #include <stdlib.h>
 #include <stdarg.h>
@@ -30,9 +27,8 @@
 #include <errno.h>
 #include <fcntl.h>
 
-#include "openat.h"
-
 #include "error.h"
+#include "exitfail.h"
 #include "save-cwd.h"
 
 #include "gettext.h"
@@ -46,42 +42,44 @@ int
 rpl_openat (int fd, char const *filename, int flags, ...)
 {
   struct saved_cwd saved_cwd;
-  int saved_errno = 0;
+  int saved_errno;
   int new_fd;
-  mode_t mode;
+  mode_t mode = 0;
 
   if (flags & O_CREAT)
     {
       va_list arg;
       va_start (arg, flags);
+
+      /* Assume that mode_t is passed compatibly with mode_t's type
+        after argument promotion.  */
       mode = va_arg (arg, mode_t);
+
       va_end (arg);
     }
-  else
-    {
-      mode = 0;
-    }
 
   if (fd == AT_FDCWD || *filename == '/')
     return open (filename, flags, mode);
 
   if (save_cwd (&saved_cwd) != 0)
-    error (EXIT_FAILURE, errno,
+    error (exit_failure, errno,
           _("openat: unable to record current working directory"));
+
   if (fchdir (fd) != 0)
     {
+      saved_errno = errno;
       free_cwd (&saved_cwd);
+      errno = saved_errno;
       return -1;
     }
 
   new_fd = open (filename, flags, mode);
-  if (new_fd < 0)
-    saved_errno = errno;
+  saved_errno = errno;
 
   if (restore_cwd (&saved_cwd) != 0)
-    error (EXIT_FAILURE, errno,
+    error (exit_failure, errno,
           _("openat: unable to restore working directory"));
-  errno = saved_errno;
 
+  errno = saved_errno;
   return new_fd;
 }
Index: lib/openat.h
===================================================================
RCS file: /fetish/cu/lib/openat.h,v
retrieving revision 1.2
diff -p -u -r1.2 openat.h
--- lib/openat.h        28 Nov 2004 22:42:08 -0000      1.2
+++ lib/openat.h        3 Dec 2004 06:43:15 -0000
@@ -1,10 +1,28 @@
+/* provide a replacement openat function
+   Copyright (C) 2004 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+/* written by Jim Meyering */
+
 #if HAVE_FCNTL_H
 # include <fcntl.h>
 #endif
 
 #ifndef AT_FDCWD
-/* FIXME: use the same value Solaris uses */
-# define AT_FDCWD -999
+# define AT_FDCWD (-3041965) /* same value as Solaris 9 */
 
 # ifdef __OPENAT_PREFIX
 #  undef openat
Index: m4/openat.m4
===================================================================
RCS file: /fetish/cu/m4/openat.m4,v
retrieving revision 1.1
diff -p -u -r1.1 openat.m4
--- m4/openat.m4        28 Nov 2004 20:55:40 -0000      1.1
+++ m4/openat.m4        3 Dec 2004 07:00:16 -0000
@@ -1,10 +1,27 @@
-#serial 1
+#serial 2
+# See if we need to use our replacement for Solaris' openat function.
+
+# Copyright (C) 2004 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 
 # Written by Jim Meyering.
-# See if we need to use our replacement for Solaris' openat function.
 
 AC_DEFUN([gl_FUNC_OPENAT],
 [
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   AC_REPLACE_FUNCS(openat)
   case $ac_cv_func_openat in
   yes) ;;