open.c revision 65470 
1/* $FreeBSD: head/lib/libstand/open.c 65470 2000-09-05 09:52:50Z msmith $ */
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 "stand.h"
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 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 = (struct devsw *)0;
106    f->f_ops = (struct fs_ops *)0;
107    f->f_offset = 0;
108    f->f_devdata = NULL;
109    file = (char *)0;
110    error = devopen(f, fname, &file);
111    if (error ||
112	(((f->f_flags & F_NODEV) == 0) && f->f_dev == (struct devsw *)0))
113	goto err;
114
115    /* see if we opened a raw device; otherwise, 'file' is the file name. */
116    if (file == (char *)0 || *file == '\0') {
117	f->f_flags |= F_RAW;
118	return (fd);
119    }
120
121    /* pass file name to the different filesystem open routines */
122    besterror = ENOENT;
123    for (i = 0; file_system[i] != NULL; i++) {
124
125	error = ((*file_system[i]).fo_open)(file, f);
126	if (error == 0) {
127
128	    f->f_ops = file_system[i];
129	    o_rainit(f);
130	    return (fd);
131	}
132	if (error != EINVAL)
133	    besterror = error;
134    }
135    error = besterror;
136
137    if ((f->f_flags & F_NODEV) == 0)
138	f->f_dev->dv_close(f);
139    if (error)
140	devclose(f);
141
142 err:
143    f->f_flags = 0;
144    errno = error;
145    return (-1);
146}
147