1/*	$NetBSD: open.c,v 1.16 1997/01/28 09:41:03 pk Exp $	*/
2
3/*
4 * Copyright (c) 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * The Mach Operating System project at Carnegie-Mellon University.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 *	@(#)open.c	8.1 (Berkeley) 6/11/93
35 *
36 *
37 * Copyright (c) 1989, 1990, 1991 Carnegie Mellon University
38 * All Rights Reserved.
39 *
40 * Author: Alessandro Forin
41 *
42 * Permission to use, copy, modify and distribute this software and its
43 * documentation is hereby granted, provided that both the copyright
44 * notice and this permission notice appear in all copies of the
45 * software, derivative works or modified versions, and any portions
46 * thereof, and that both notices appear in supporting documentation.
47 *
48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
49 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
50 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
51 *
52 * Carnegie Mellon requests users of this software to return to
53 *
54 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
55 *  School of Computer Science
56 *  Carnegie Mellon University
57 *  Pittsburgh PA 15213-3890
58 *
59 * any improvements or extensions that they make and grant Carnegie the
60 * rights to redistribute these changes.
61 */
62
63#include <sys/cdefs.h>
64
65#include "stand.h"
66
67struct fs_ops *exclusive_file_system;
68
69struct open_file files[SOPEN_MAX];
70
71static int
72o_gethandle(void)
73{
74	int fd;
75
76	for (fd = 0; fd < SOPEN_MAX; fd++)
77		if (files[fd].f_flags == 0)
78			return (fd);
79	return (-1);
80}
81
82static void
83o_rainit(struct open_file *f)
84{
85	f->f_rabuf = malloc(SOPEN_RASIZE);
86	f->f_ralen = 0;
87	f->f_raoffset = 0;
88}
89
90int
91open(const char *fname, int mode)
92{
93	struct fs_ops *fs;
94	struct open_file *f;
95	int fd, i, error, besterror;
96	const char *file;
97
98	if ((fd = o_gethandle()) == -1) {
99		errno = EMFILE;
100		return (-1);
101	}
102
103	f = &files[fd];
104	f->f_flags = mode + 1;
105	f->f_dev = NULL;
106	f->f_ops = NULL;
107	f->f_offset = 0;
108	f->f_devdata = NULL;
109	file = NULL;
110
111	if (exclusive_file_system != NULL) {
112		fs = exclusive_file_system;
113		error = (fs->fo_open)(fname, f);
114		if (error == 0)
115			goto ok;
116		goto err;
117	}
118
119	error = devopen(f, fname, &file);
120	if (error ||
121	    (((f->f_flags & F_NODEV) == 0) && f->f_dev == NULL))
122		goto err;
123
124	/* see if we opened a raw device; otherwise, 'file' is the file name. */
125	if (file == NULL || *file == '\0') {
126		f->f_flags |= F_RAW;
127		f->f_rabuf = NULL;
128		return (fd);
129	}
130
131	/* pass file name to the different filesystem open routines */
132	besterror = ENOENT;
133	for (i = 0; file_system[i] != NULL; i++) {
134		fs = file_system[i];
135		error = (fs->fo_open)(file, f);
136		if (error == 0)
137			goto ok;
138		if (error != EINVAL)
139			besterror = error;
140	}
141	error = besterror;
142
143	if ((f->f_flags & F_NODEV) == 0 && f->f_dev != NULL)
144		f->f_dev->dv_close(f);
145	if (error)
146		devclose(f);
147
148err:
149	f->f_flags = 0;
150	errno = error;
151	return (-1);
152
153ok:
154	f->f_ops = fs;
155	o_rainit(f);
156	return (fd);
157}
158