xref: /netbsd-src/lib/libutil/opendisk.c (revision 06be8101a16cc95f40783b3cb7afd12112103a9a)
1 /*	$NetBSD: opendisk.c,v 1.8 2001/11/01 06:53:25 lukem Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Luke Mewburn.
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 NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>
40 #if defined(LIBC_SCCS) && !defined(lint)
41 __RCSID("$NetBSD: opendisk.c,v 1.8 2001/11/01 06:53:25 lukem Exp $");
42 #endif
43 
44 #include <sys/param.h>
45 
46 #include <assert.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <paths.h>
50 #include <stdio.h>
51 #include <string.h>
52 #include <unistd.h>
53 #include <util.h>
54 
55 int
56 opendisk(const char *path, int flags, char *buf, size_t buflen, int iscooked)
57 {
58 	struct stat sb;
59 	int	f, pass, rawpart, serrno;
60 
61 	if (buf == NULL) {
62 		errno = EFAULT;
63 		return (-1);
64 	}
65 	if ((flags & O_CREAT) != 0) {
66 		errno = EINVAL;
67 		return (-1);
68 	}
69 
70 	rawpart = getrawpartition();
71 	if (rawpart < 0)
72 		return (-1);	/* sysctl(3) in getrawpartition sets errno */
73 
74 	for (pass = 0; pass < 4; pass++) {
75 		switch (pass) {
76 		case 0:
77 			snprintf(buf, buflen, "%s", path);
78 			break;
79 		case 1:
80 			snprintf(buf, buflen, "%s%c", path, 'a' + rawpart);
81 			break;
82 		case 2:
83 			if (strchr(path, '/') != NULL)
84 				return (-1);
85 			snprintf(buf, buflen, "%s%s%s", _PATH_DEV,
86 			    iscooked ? "" : "r", path);
87 			break;
88 		case 3:
89 			snprintf(buf, buflen, "%s%s%s%c", _PATH_DEV,
90 			    iscooked ? "" : "r", path, 'a' + rawpart);
91 			break;
92 		}
93 		f = open(buf, flags);
94 		if (f == -1 && errno != ENOENT)
95 			return (-1);
96 		if (f != -1) {
97 			if (fstat(f, &sb) == -1) {
98 				serrno = errno;
99 				close (f);
100 				errno = serrno;
101 				f = -1;
102 			} else if ((!iscooked && !S_ISCHR(sb.st_mode)) ||
103 			    	   ( iscooked && !S_ISBLK(sb.st_mode)) ) {
104 				close (f);
105 				errno = ENODEV;
106 				f = -1;
107 			}
108 			return (f);
109 		}
110 	}
111 	return (f);
112 }
113