1/*	$OpenBSD: readlabel.c,v 1.15 2019/06/28 13:32:43 deraadt Exp $	*/
2
3/*
4 * Copyright (c) 1996, Jason Downs.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS
16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT,
19 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
20 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/types.h>
29#include <sys/disk.h>
30#include <sys/dkio.h>
31#define DKTYPENAMES
32#include <sys/disklabel.h>
33#include <sys/ioctl.h>
34#include <sys/stat.h>
35#include <stdio.h>
36#include <err.h>
37#include <errno.h>
38#include <limits.h>
39#include <fcntl.h>
40#include <paths.h>
41#include <string.h>
42#include <unistd.h>
43
44#include "util.h"
45
46/*
47 * Try to get a disklabel for the specified device, and return mount_xxx
48 * style filesystem type name for the specified partition.
49 */
50char *
51readlabelfs(char *device, int verbose)
52{
53	char rpath[PATH_MAX];
54	struct dk_diskmap dm;
55	struct disklabel dk;
56	char part, *type;
57	struct stat sbuf;
58	int fd = -1;
59
60	/* Perform disk mapping if device is given as a DUID. */
61	if (isduid(device, 0)) {
62		if ((fd = open("/dev/diskmap", O_RDONLY|O_CLOEXEC)) != -1) {
63			bzero(&dm, sizeof(struct dk_diskmap));
64			strlcpy(rpath, device, sizeof(rpath));
65			part = rpath[strlen(rpath) - 1];
66			dm.device = rpath;
67			dm.fd = fd;
68			dm.flags = DM_OPENPART;
69			if (ioctl(fd, DIOCMAP, &dm) == -1)
70				close(fd);
71			else
72				goto disklabel;
73		}
74	}
75
76	/* Assuming device is of the form /dev/??p, build a raw partition. */
77	if (stat(device, &sbuf) == -1) {
78		if (verbose)
79			warn("%s", device);
80		return (NULL);
81	}
82	switch (sbuf.st_mode & S_IFMT) {
83	case S_IFCHR:
84		/* Ok... already a raw device.  Hmm. */
85		strlcpy(rpath, device, sizeof(rpath));
86
87		/* Change partition name. */
88		part = rpath[strlen(rpath) - 1];
89		rpath[strlen(rpath) - 1] = 'a' + getrawpartition();
90		break;
91	case S_IFBLK:
92		if (strlen(device) > sizeof(_PATH_DEV) - 1) {
93			snprintf(rpath, sizeof(rpath), "%sr%s", _PATH_DEV,
94			    &device[sizeof(_PATH_DEV) - 1]);
95			/* Change partition name. */
96			part = rpath[strlen(rpath) - 1];
97			rpath[strlen(rpath) - 1] = 'a' + getrawpartition();
98			break;
99		}
100		/* FALLTHROUGH */
101	default:
102		if (verbose)
103			warnx("%s: not a device node", device);
104		return (NULL);
105	}
106
107	/* If rpath doesn't exist, change that partition back. */
108	fd = open(rpath, O_RDONLY|O_CLOEXEC);
109	if (fd == -1) {
110		if (errno == ENOENT) {
111			rpath[strlen(rpath) - 1] = part;
112
113			fd = open(rpath, O_RDONLY|O_CLOEXEC);
114			if (fd == -1) {
115				if (verbose)
116					warn("%s", rpath);
117				return (NULL);
118			}
119		} else {
120			if (verbose)
121				warn("%s", rpath);
122			return (NULL);
123		}
124	}
125
126disklabel:
127
128	if (ioctl(fd, DIOCGDINFO, &dk) == -1) {
129		if (verbose)
130			warn("%s: couldn't read disklabel", rpath);
131		close(fd);
132		return (NULL);
133	}
134	close(fd);
135
136	if (dk.d_partitions[part - 'a'].p_fstype >= FSMAXTYPES) {
137		if (verbose)
138			warnx("%s: bad filesystem type in label", rpath);
139		return (NULL);
140	}
141
142	type = fstypesnames[dk.d_partitions[part - 'a'].p_fstype];
143	return ((type[0] == '\0') ? NULL : type);
144}
145