open.c revision 84221 
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 <sys/cdefs.h>
68__FBSDID("$FreeBSD: head/lib/libstand/open.c 84221 2001-09-30 22:28:01Z dillon $");
69
70#include "stand.h"
71
72struct open_file files[SOPEN_MAX];
73
74static int
75o_gethandle(void)
76{
77    int		fd;
78
79    for (fd = 0; fd < SOPEN_MAX; fd++)
80	if (files[fd].f_flags == 0)
81	    return(fd);
82    return(-1);
83}
84
85static void
86o_rainit(struct open_file *f)
87{
88    f->f_rabuf = malloc(SOPEN_RASIZE);
89    f->f_ralen = 0;
90    f->f_raoffset = 0;
91}
92
93int
94open(const char *fname, int mode)
95{
96    struct open_file	*f;
97    int			fd, i, error, besterror;
98    const char		*file;
99
100    if ((fd = o_gethandle()) == -1) {
101	errno = EMFILE;
102	return(-1);
103    }
104
105    f = &files[fd];
106    f->f_flags = mode + 1;
107    f->f_dev = (struct devsw *)0;
108    f->f_ops = (struct fs_ops *)0;
109    f->f_offset = 0;
110    f->f_devdata = NULL;
111    file = (char *)0;
112    error = devopen(f, fname, &file);
113    if (error ||
114	(((f->f_flags & F_NODEV) == 0) && f->f_dev == (struct devsw *)0))
115	goto err;
116
117    /* see if we opened a raw device; otherwise, 'file' is the file name. */
118    if (file == (char *)0 || *file == '\0') {
119	f->f_flags |= F_RAW;
120	return (fd);
121    }
122
123    /* pass file name to the different filesystem open routines */
124    besterror = ENOENT;
125    for (i = 0; file_system[i] != NULL; i++) {
126
127	error = ((*file_system[i]).fo_open)(file, f);
128	if (error == 0) {
129
130	    f->f_ops = file_system[i];
131	    o_rainit(f);
132	    return (fd);
133	}
134	if (error != EINVAL)
135	    besterror = error;
136    }
137    error = besterror;
138
139    if ((f->f_flags & F_NODEV) == 0)
140	f->f_dev->dv_close(f);
141    if (error)
142	devclose(f);
143
144 err:
145    f->f_flags = 0;
146    errno = error;
147    return (-1);
148}
149