I installed this, imported from coreutils. It addresses the issue
that `unlink ("directory")' works on some hosts (e.g., Solaris,
OpenBSD) but not others (e.g., GNU/Linux, FreeBSD). Solaris 10 has a
new wrinkle: you can add/remove the privilege of unlinking a
directory.
2005-05-14 Paul Eggert <[EMAIL PROTECTED]>
New unlinkdir module.
* MODULES.html.sh (File system functions): Add unlinkdir.
* lib/unlinkdir.c, lib/unlinkdir.h, m4/unlinkdir.m4, modules/unlinkdir:
New file.
Index: MODULES.html.sh
===================================================================
RCS file: /cvsroot/gnulib/gnulib/MODULES.html.sh,v
retrieving revision 1.81
diff -p -u -r1.81 MODULES.html.sh
--- MODULES.html.sh 14 May 2005 06:03:57 -0000 1.81
+++ MODULES.html.sh 15 May 2005 06:07:19 -0000
@@ -1826,6 +1826,7 @@ func_all_modules ()
func_module same
func_module save-cwd
func_module savedir
+ func_module unlinkdir
func_module utimecmp
func_module utimens
func_module xgetcwd
--- /dev/null 2003-03-18 13:55:57 -0800
+++ lib/unlinkdir.c 2005-05-14 22:53:47 -0700
@@ -0,0 +1,70 @@
+/* unlinkdir.c - determine (and maybe change) whether we can unlink directories
+
+ Copyright (C) 2005 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+/* Written by Paul Eggert and Jim Meyering. */
+
+#include <config.h>
+
+#include "unlinkdir.h"
+
+#if HAVE_PRIV_H
+# include <priv.h>
+#endif
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#if ! UNLINK_CANNOT_UNLINK_DIR
+
+/* Return true if we cannot unlink directories, false if we might be
+ able to unlink directories. If possible, tell the kernel we don't
+ want to be able to unlink directories, so that we can return true. */
+
+bool
+cannot_unlink_dir (void)
+{
+ static bool initialized;
+ static bool cannot;
+
+ if (! initialized)
+ {
+# if defined PRIV_EFFECTIVE && defined PRIV_SYS_LINKDIR
+ /* We might be able to unlink directories if we cannot
+ determine our privileges, or if we have the
+ PRIV_SYS_LINKDIR privilege and cannot delete it. */
+ priv_set_t *pset = priv_allocset ();
+ if (pset)
+ {
+ cannot =
+ (getppriv (PRIV_EFFECTIVE, pset) == 0
+ && (! priv_ismember (pset, PRIV_SYS_LINKDIR)
+ || (priv_delset (pset, PRIV_SYS_LINKDIR) == 0
+ && setppriv (PRIV_SET, PRIV_EFFECTIVE, pset) == 0)));
+ priv_freeset (pset);
+ }
+# else
+ /* In traditional Unix, only root can unlink directories. */
+ cannot = (geteuid () != 0);
+# endif
+ initialized = true;
+ }
+
+ return cannot;
+}
+
+#endif
--- /dev/null 2003-03-18 13:55:57 -0800
+++ lib/unlinkdir.h 2005-05-14 21:51:47 -0700
@@ -0,0 +1,27 @@
+/* unlinkdir.h - determine (and maybe change) whether we can unlink directories
+
+ Copyright (C) 2005 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+/* Written by Paul Eggert and Jim Meyering. */
+
+#include <stdbool.h>
+
+#if UNLINK_CANNOT_UNLINK_DIR
+static bool cannot_unlink_dir (void) { return true; }
+#else
+bool cannot_unlink_dir (void);
+#endif
--- /dev/null 2003-03-18 13:55:57 -0800
+++ m4/unlinkdir.m4 2005-05-14 21:51:54 -0700
@@ -0,0 +1,34 @@
+#serial 2
+
+# Copyright (C) 2005 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Written by Paul Eggert.
+
+AC_DEFUN([gl_UNLINKDIR],
+[
+ AC_REQUIRE([AC_CANONICAL_HOST])
+ AC_CHECK_HEADERS_ONCE(priv.h unistd.h)
+
+ AC_LIBSOURCES([unlinkdir.c, unlinkdir.h])
+ AC_LIBOBJ([unlinkdir])
+
+ # The Hurd, the Linux kernel, the FreeBSD kernel version 2.2 and later,
+ # and Cygwin never let anyone (even root) unlink directories.
+ # If anyone knows of another system for which unlink can never
+ # remove a directory, please report it to <bug-coreutils@gnu.org>.
+ # Unfortunately this is difficult to test for, since it requires root access
+ # and might create garbage in the file system,
+ # so the code below simply relies on the kernel name and version number.
+ case $host in
+ *-*-gnu[0-9]* | \
+ *-*-linux-* | *-*-linux | \
+ *-*-freebsd2.2* | *-*-freebsd[3-9]* | *-*-freebsd[1-9][0-9]* | \
+ *-cygwin)
+ AC_DEFINE([UNLINK_CANNOT_UNLINK_DIR], 1,
+ [Define to 1 if unlink (dir) cannot possibly succeed.]);;
+ esac
+])
--- /dev/null 2003-03-18 13:55:57 -0800
+++ modules/unlinkdir 2005-05-14 21:54:20 -0700
@@ -0,0 +1,24 @@
+Description:
+Determine (and maybe change) whether we can unlink directories.
+
+Files:
+lib/unlinkdir.h
+lib/unlinkdir.c
+m4/unlinkdir.m4
+
+Depends-on:
+stdbool
+
+configure.ac:
+gl_UNLINKDIR
+
+Makefile.am:
+
+Include:
+"unlinkdir.h"
+
+License:
+GPL
+
+Maintainer:
+Paul Eggert, Jim Meyering
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