text: /*	$NetBSD: open.c,v 1.16 1997/01/28 09:41:03 pk Exp $	*/
  
  /*-
   * Copyright (c) 1993
   *	The Regents of the University of California.  All rights reserved.
   *
   * This code is derived from software contributed to Berkeley by
   * The Mach Operating System project at Carnegie-Mellon University.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   *	@(#)open.c	8.1 (Berkeley) 6/11/93
   *
   *
   * Copyright (c) 1989, 1990, 1991 Carnegie Mellon University
   * All Rights Reserved.
   *
   * Author: Alessandro Forin
   *
   * Permission to use, copy, modify and distribute this software and its
   * documentation is hereby granted, provided that both the copyright
   * notice and this permission notice appear in all copies of the
   * software, derivative works or modified versions, and any portions
   * thereof, and that both notices appear in supporting documentation.
   *
   * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
   * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
   * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
   *
   * Carnegie Mellon requests users of this software to return to
   *
   *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
   *  School of Computer Science
   *  Carnegie Mellon University
   *  Pittsburgh PA 15213-3890
   *
   * any improvements or extensions that they make and grant Carnegie the
   * rights to redistribute these changes.
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD$");
  
  #include "stand.h"
  
  struct fs_ops *exclusive_file_system;
  
  struct open_file files[SOPEN_MAX];
  
  static int
  o_gethandle(void)
  {
  	int fd;
  
  	for (fd = 0; fd < SOPEN_MAX; fd++)
  		if (files[fd].f_flags == 0)
  			return (fd);
  	return (-1);
  }
  
  static void
  o_rainit(struct open_file *f)
  {
  	f->f_rabuf = malloc(SOPEN_RASIZE);
  	f->f_ralen = 0;
  	f->f_raoffset = 0;
  }
  
  int
  open(const char *fname, int mode)
  {
  	struct fs_ops *fs;
  	struct open_file *f;
  	int fd, i, error, besterror;
  	const char *file;
  
  	if ((fd = o_gethandle()) == -1) {
  		errno = EMFILE;
  		return (-1);
  	}
  
  	f = &files[fd];
  	f->f_flags = mode + 1;
  	f->f_dev = NULL;
  	f->f_ops = NULL;
  	f->f_offset = 0;
  	f->f_devdata = NULL;
  	file = NULL;
  
  	if (exclusive_file_system != NULL) {
  		fs = exclusive_file_system;
  		error = (fs->fo_open)(fname, f);
  		if (error == 0)
  			goto ok;
  		goto err;
  	}
  
  	error = devopen(f, fname, &file);
  	if (error ||
  	    (((f->f_flags & F_NODEV) == 0) && f->f_dev == NULL))
  		goto err;
  
  	/* see if we opened a raw device; otherwise, 'file' is the file name. */
  	if (file == NULL || *file == '\0') {
  		f->f_flags |= F_RAW;
  		f->f_rabuf = NULL;
  		return (fd);
  	}
  
  	/* pass file name to the different filesystem open routines */
  	besterror = ENOENT;
  	for (i = 0; file_system[i] != NULL; i++) {
  		fs = file_system[i];
  		error = (fs->fo_open)(file, f);
  		if (error == 0)
  			goto ok;
  		if (error != EINVAL)
  			besterror = error;
  	}
  	error = besterror;
  
  	if ((f->f_flags & F_NODEV) == 0 && f->f_dev != NULL)
  		f->f_dev->dv_close(f);
  	if (error)
  		devclose(f);
  
  err:
  	f->f_flags = 0;
  	errno = error;
  	return (-1);
  
  ok:
  	f->f_ops = fs;
  	o_rainit(f);
  	return (fd);
  }
  