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/* 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. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "unlinkdir.h"
#if HAVE_PRIV_H
# include <priv.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. */
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
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