view lib/write-any-file.c @ 11538:af683213eeb0

priv-set: new module and accompanying tests; adapt write-any-file * lib/priv-set.c: New file. * lib/priv-set.h: New file. * lib/unlinkdir.c: Make cannot_unlink_dir thread-safe. * lib/write-any-file.c: Simplify by using priv-set module. * m4/priv-set.m4: New file. * modules/priv-set: New file. * modules/unlinkdir: Add dependency on priv-set module. * modules/write-any-file: Likewise. These changes address a problem that originally arose with GNU tar: http://thread.gmane.org/gmane.comp.gnu.tar.bugs/3242 Tests for module 'priv-set'. * modules/priv-set-tests: New file.
author David Bartley <dtbartle@csclub.uwaterloo.ca>
date Wed, 29 Apr 2009 03:52:26 -0400
parents bbbbbf4cd1c5
children b5e42ef33b49
line wrap: on
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/* Determine whether we can write any file.

   Copyright (C) 2007 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
   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, see <http://www.gnu.org/licenses/>.  */

/* Written by Paul Eggert.  */

#include <config.h>

#include "write-any-file.h"
#include "priv-set.h"

#include <unistd.h>

/* Return true if we know that we can write any file, including
   writing directories.  */

bool
can_write_any_file (void)
{
  static bool initialized;
  static bool can_write;

  if (! initialized)
    {
      bool can = false;
#if defined PRIV_FILE_DAC_WRITE
      can = (priv_set_ismember (PRIV_FILE_DAC_WRITE) == 1);
#else
      /* In traditional Unix, only root can unlink directories.  */
      can = (geteuid () == 0);
#endif
      can_write = can;
      initialized = true;
    }

  return can_write;
}