Logo Search packages:      
Sourcecode: coreutils version File versions


/* unlinkdir.c - determine (and maybe change) whether we can unlink directories

   Copyright (C) 2005-2006, 2009 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 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
   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, see <http://www.gnu.org/licenses/>.  */

/* Written by Paul Eggert and Jim Meyering.  */

#include <config.h>

#include "unlinkdir.h"

# include <priv.h>
#include <unistd.h>


/* 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.

   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.  */

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;


Generated by  Doxygen 1.6.0   Back to index