open.c revision 65654 
1/* $FreeBSD: head/lib/libstand/open.c 65654 2000-09-10 01:10:15Z ps $ */
2/*	$NetBSD: open.c,v 1.16 1997/01/28 09:41:03 pk Exp $	*/
3
4/*-
5 * Copyright (c) 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * The Mach Operating System project at Carnegie-Mellon University.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgement:
21 *	This product includes software developed by the University of
22 *	California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 *	@(#)open.c	8.1 (Berkeley) 6/11/93
40 *
41 *
42 * Copyright (c) 1989, 1990, 1991 Carnegie Mellon University
43 * All Rights Reserved.
44 *
45 * Author: Alessandro Forin
46 *
47 * Permission to use, copy, modify and distribute this software and its
48 * documentation is hereby granted, provided that both the copyright
49 * notice and this permission notice appear in all copies of the
50 * software, derivative works or modified versions, and any portions
51 * thereof, and that both notices appear in supporting documentation.
52 *
53 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
54 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
55 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
56 *
57 * Carnegie Mellon requests users of this software to return to
58 *
59 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
60 *  School of Computer Science
61 *  Carnegie Mellon University
62 *  Pittsburgh PA 15213-3890
63 *
64 * any improvements or extensions that they make and grant Carnegie the
65 * rights to redistribute these changes.
66 */
67
68#include <string.h>
69#include "stand.h"
70
71struct open_file files[SOPEN_MAX];
72
73static int
74o_gethandle(void)
75{
76    int		fd;
77
78    for (fd = 0; fd < SOPEN_MAX; fd++)
79	if (files[fd].f_flags == 0)
80	    return(fd);
81    return(-1);
82}
83
84static void
85o_rainit(struct open_file *f)
86{
87    f->f_rabuf = malloc(SOPEN_RASIZE);
88    f->f_ralen = 0;
89    f->f_raoffset = 0;
90}
91
92int
93open(const char *fname, int mode)
94{
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    error = devopen(f, fname, &file);
112    if (error ||
113	(((f->f_flags & F_NODEV) == 0) && f->f_dev == (struct devsw *)0))
114	goto err;
115
116    /* see if we opened a raw device; otherwise, 'file' is the file name. */
117    if (file == (char *)0 || *file == '\0') {
118	f->f_flags |= F_RAW;
119	return (fd);
120    }
121
122    /* pass file name to the different filesystem open routines */
123    besterror = ENOENT;
124    for (i = 0; file_system[i] != NULL; i++) {
125
126	error = ((*file_system[i]).fo_open)(file, f);
127	if (error == 0) {
128
129	    f->f_ops = file_system[i];
130	    o_rainit(f);
131	    return (fd);
132	}
133	if (error != EINVAL)
134	    besterror = error;
135    }
136    error = besterror;
137
138    if ((f->f_flags & F_NODEV) == 0)
139	f->f_dev->dv_close(f);
140    if (error)
141	devclose(f);
142
143 err:
144    f->f_flags = 0;
145    errno = error;
146    return (-1);
147}
148