open.c revision 38451 
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. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *	This product includes software developed by the University of
21 *	California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 *    may be used to endorse or promote products derived from this software
24 *    without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 *	@(#)open.c	8.1 (Berkeley) 6/11/93
39 *
40 *
41 * Copyright (c) 1989, 1990, 1991 Carnegie Mellon University
42 * All Rights Reserved.
43 *
44 * Author: Alessandro Forin
45 *
46 * Permission to use, copy, modify and distribute this software and its
47 * documentation is hereby granted, provided that both the copyright
48 * notice and this permission notice appear in all copies of the
49 * software, derivative works or modified versions, and any portions
50 * thereof, and that both notices appear in supporting documentation.
51 *
52 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
53 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
54 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
55 *
56 * Carnegie Mellon requests users of this software to return to
57 *
58 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
59 *  School of Computer Science
60 *  Carnegie Mellon University
61 *  Pittsburgh PA 15213-3890
62 *
63 * any improvements or extensions that they make and grant Carnegie the
64 * rights to redistribute these changes.
65 */
66
67#include "stand.h"
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
82
83int
84open(const char *fname, int mode)
85{
86    struct open_file	*f;
87    int			fd, i, error, besterror;
88    char		*file;
89
90    if ((fd = o_gethandle()) == -1) {
91	errno = EMFILE;
92	return(-1);
93    }
94
95    f = &files[fd];
96    f->f_flags = mode + 1;
97    f->f_dev = (struct devsw *)0;
98    f->f_ops = (struct fs_ops *)0;
99    f->f_offset = 0;
100    f->f_devdata = NULL;
101    file = (char *)0;
102    error = devopen(f, fname, &file);
103    if (error ||
104	(((f->f_flags & F_NODEV) == 0) && f->f_dev == (struct devsw *)0))
105	goto err;
106
107    /* see if we opened a raw device; otherwise, 'file' is the file name. */
108    if (file == (char *)0 || *file == '\0') {
109	f->f_flags |= F_RAW;
110	return (fd);
111    }
112
113    /* pass file name to the different filesystem open routines */
114    besterror = ENOENT;
115    for (i = 0; file_system[i] != NULL; i++) {
116
117	error = ((*file_system[i]).fo_open)(file, f);
118	if (error == 0) {
119
120	    f->f_ops = file_system[i];
121	    return (fd);
122	}
123	if (error != EINVAL)
124	    besterror = error;
125    }
126    error = besterror;
127
128    if ((f->f_flags & F_NODEV) == 0)
129	f->f_dev->dv_close(f);
130    if (error)
131	devclose(f);
132
133 err:
134    f->f_flags = 0;
135    errno = error;
136    return (-1);
137}
138