open.c revision 344289 
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 * 4. 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__FBSDID("$FreeBSD: stable/11/stand/libsa/open.c 344289 2019-02-19 18:45:40Z kevans $");
65
66#include "stand.h"
67
68struct fs_ops *exclusive_file_system;
69
70struct open_file files[SOPEN_MAX];
71
72static int
73o_gethandle(void)
74{
75    int		fd;
76
77    for (fd = 0; fd < SOPEN_MAX; fd++)
78	if (files[fd].f_flags == 0)
79	    return(fd);
80    return(-1);
81}
82
83static void
84o_rainit(struct open_file *f)
85{
86    f->f_rabuf = malloc(SOPEN_RASIZE);
87    f->f_ralen = 0;
88    f->f_raoffset = 0;
89}
90
91int
92open(const char *fname, int mode)
93{
94    struct fs_ops	*fs;
95    struct open_file	*f;
96    int			fd, i, error, besterror;
97    const char		*file;
98
99    if ((fd = o_gethandle()) == -1) {
100	errno = EMFILE;
101	return(-1);
102    }
103
104    f = &files[fd];
105    f->f_flags = mode + 1;
106    f->f_dev = (struct devsw *)0;
107    f->f_ops = (struct fs_ops *)0;
108    f->f_offset = 0;
109    f->f_devdata = NULL;
110    file = (char *)0;
111
112    if (exclusive_file_system != NULL) {
113	fs = exclusive_file_system;
114	error = (fs->fo_open)(fname, f);
115	if (error == 0)
116	    goto ok;
117	goto err;
118    }
119
120    error = devopen(f, fname, &file);
121    if (error ||
122	(((f->f_flags & F_NODEV) == 0) && f->f_dev == (struct devsw *)0))
123	goto err;
124
125    /* see if we opened a raw device; otherwise, 'file' is the file name. */
126    if (file == (char *)0 || *file == '\0') {
127	f->f_flags |= F_RAW;
128	f->f_rabuf = NULL;
129	return (fd);
130    }
131
132    /* pass file name to the different filesystem open routines */
133    besterror = ENOENT;
134    for (i = 0; file_system[i] != NULL; i++) {
135	fs = file_system[i];
136	error = (fs->fo_open)(file, f);
137	if (error == 0)
138	    goto ok;
139	if (error != EINVAL)
140	    besterror = error;
141    }
142    error = besterror;
143
144    if ((f->f_flags & F_NODEV) == 0 && f->f_dev != NULL)
145	f->f_dev->dv_close(f);
146    if (error)
147	devclose(f);
148
149 err:
150    f->f_flags = 0;
151    errno = error;
152    return (-1);
153
154 ok:
155    f->f_ops = fs;
156    o_rainit(f);
157    return (fd);
158}
159