/* dirfd.c -- return the file descriptor associated with an open DIR*

   Copyright (C) 2001, 2006, 2008-2018 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 <https://www.gnu.org/licenses/>.  */

/* Written by Jim Meyering. */

#include <config.h>

#include <dirent.h>

#include <errno.h>

#ifdef __KLIBC__

# include <stdlib.h>

# include <io.h>

static struct dirp_fd_list

{

  DIR *dirp;

  int fd;

  struct dirp_fd_list *next;

} *dirp_fd_start = NULL;

/* Register fd associated with dirp to dirp_fd_list. */

int

_gl_register_dirp_fd (int fd, DIR *dirp)

{

  struct dirp_fd_list *new_dirp_fd = malloc (sizeof *new_dirp_fd);

  if (!new_dirp_fd)

    return -1;

  new_dirp_fd->dirp = dirp;

  new_dirp_fd->fd = fd;

  new_dirp_fd->next = dirp_fd_start;

  dirp_fd_start = new_dirp_fd;

  return 0;

}

/* Unregister fd from dirp_fd_list with closing it */

void

_gl_unregister_dirp_fd (int fd)

{

  struct dirp_fd_list *dirp_fd;

  struct dirp_fd_list *dirp_fd_prev;

  for (dirp_fd_prev = NULL, dirp_fd = dirp_fd_start; dirp_fd;

       dirp_fd_prev = dirp_fd, dirp_fd = dirp_fd->next)

    {

      if (dirp_fd->fd == fd)

        {

          if (dirp_fd_prev)

            dirp_fd_prev->next = dirp_fd->next;

          else  /* dirp_fd == dirp_fd_start */

            dirp_fd_start = dirp_fd_start->next;

          close (fd);

          free (dirp_fd);

          break;

        }

    }

}

#endif

int

dirfd (DIR *dir_p)

{

  int fd = DIR_TO_FD (dir_p);

  if (fd == -1)

#ifndef __KLIBC__

    errno = ENOTSUP;

#else

    {

      struct dirp_fd_list *dirp_fd;

      for (dirp_fd = dirp_fd_start; dirp_fd; dirp_fd = dirp_fd->next)

        if (dirp_fd->dirp == dir_p)

          return dirp_fd->fd;

      errno = EINVAL;

    }

#endif

  return fd;

}