unlinkdir: cannot_unlink_dir may modify process state

[gnulib.git] / lib / unlinkdir.c

diff --git a/lib/unlinkdir.c b/lib/unlinkdir.c
index b12d2a4..9c3ff00 100644 (file)
--- a/lib/unlinkdir.c
+++ b/lib/unlinkdir.c
@@ -1,11 +1,11 @@
 /* unlinkdir.c - determine (and maybe change) whether we can unlink directories
 
-   Copyright (C) 2005 Free Software Foundation, Inc.
+   Copyright (C) 2005-2006, 2009 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify
+   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.
+   the Free Software Foundation; either version 3 of the License, 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
@@ -13,8 +13,7 @@
    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.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 /* Written by Paul Eggert and Jim Meyering.  */
 
@@ -25,15 +24,17 @@
 #if HAVE_PRIV_H
 # include <priv.h>
 #endif
-#if HAVE_UNISTD_H
-# include <unistd.h>
-#endif
+#include <unistd.h>
 
 #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.  */
+   want to be able to unlink directories, so that we can return true.
+
+   Note: this function may modify the process privilege set, to remove
+   the PRIV_SYS_LINKDIR privilege, so is neither thread-safe, nor
+   appropriate for use in a library.  */
 
 bool
 cannot_unlink_dir (void)