/*

 * Unix SMB/CIFS implementation.

 * Samba utility functions

 * Copyright (C) Volker Lendecke 2014

 *

 * 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/>.

 */

#include "replace.h"

#include "system/filesys.h"

#include "close_low_fd.h"

#ifdef HAVE_VALGRIND_VALGRIND_H

#include <valgrind/valgrind.h>

#elif defined(HAVE_VALGRIND_H)

#include <valgrind.h>

#else

#define RUNNING_ON_VALGRIND 0

#endif

_PUBLIC_ int close_low_fd(int fd)

{

  int ret, dev_null;

  if (RUNNING_ON_VALGRIND) {

    return 0;

  }

  dev_null = open("/dev/null", O_RDWR, 0);

  if ((dev_null == -1) && (errno == ENFILE)) {

    /*

     * Try to free up an fd

     */

    ret = close(fd);

    if (ret != 0) {

      return errno;

    }

    dev_null = open("/dev/null", O_RDWR, 0);

  }

  if (dev_null == -1) {

    dev_null = open("/dev/null", O_WRONLY, 0);

  }

  if (dev_null == -1) {

    return errno;

  }

  if (dev_null == fd) {

    /*

     * This can happen in the ENFILE case above

     */

    return 0;

  }

  ret = dup2(dev_null, fd);

  if (ret == -1) {

    int err = errno;

    close(dev_null);

    return err;

  }

  close(dev_null);

  return 0;

}