open.c revision 165906 
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: head/lib/libstand/open.c 165906 2007-01-09 01:02:06Z imp $");
65
66#include "stand.h"
67
68struct open_file files[SOPEN_MAX];
69
70static int
71o_gethandle(void)
72{
73    int		fd;
74
75    for (fd = 0; fd < SOPEN_MAX; fd++)
76	if (files[fd].f_flags == 0)
77	    return(fd);
78    return(-1);
79}
80
81static void
82o_rainit(struct open_file *f)
83{
84    f->f_rabuf = malloc(SOPEN_RASIZE);
85    f->f_ralen = 0;
86    f->f_raoffset = 0;
87}
88
89int
90open(const char *fname, int mode)
91{
92    struct open_file	*f;
93    int			fd, i, error, besterror;
94    const char		*file;
95
96    if ((fd = o_gethandle()) == -1) {
97	errno = EMFILE;
98	return(-1);
99    }
100
101    f = &files[fd];
102    f->f_flags = mode + 1;
103    f->f_dev = (struct devsw *)0;
104    f->f_ops = (struct fs_ops *)0;
105    f->f_offset = 0;
106    f->f_devdata = NULL;
107    file = (char *)0;
108    error = devopen(f, fname, &file);
109    if (error ||
110	(((f->f_flags & F_NODEV) == 0) && f->f_dev == (struct devsw *)0))
111	goto err;
112
113    /* see if we opened a raw device; otherwise, 'file' is the file name. */
114    if (file == (char *)0 || *file == '\0') {
115	f->f_flags |= F_RAW;
116	return (fd);
117    }
118
119    /* pass file name to the different filesystem open routines */
120    besterror = ENOENT;
121    for (i = 0; file_system[i] != NULL; i++) {
122
123	error = ((*file_system[i]).fo_open)(file, f);
124	if (error == 0) {
125
126	    f->f_ops = file_system[i];
127	    o_rainit(f);
128	    return (fd);
129	}
130	if (error != EINVAL)
131	    besterror = error;
132    }
133    error = besterror;
134
135    if ((f->f_flags & F_NODEV) == 0)
136	f->f_dev->dv_close(f);
137    if (error)
138	devclose(f);
139
140 err:
141    f->f_flags = 0;
142    errno = error;
143    return (-1);
144}
145