summaryrefslogtreecommitdiff
path: root/e2fsprogs/old_e2fsprogs/ext2fs/finddev.c
blob: 5e2cce940e3248bbf8c53b706018010a4203e3bd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
/* vi: set sw=4 ts=4: */
/*
 * finddev.c -- this routine attempts to find a particular device in
 *	/dev
 *
 * Copyright (C) 2000 Theodore Ts'o.
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Public
 * License.
 * %End-Header%
 */

#include <stdio.h>
#include <string.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#include <dirent.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_SYS_MKDEV_H
#include <sys/mkdev.h>
#endif

#include "ext2_fs.h"
#include "ext2fs.h"

struct dir_list {
	char	*name;
	struct dir_list *next;
};

/*
 * This function adds an entry to the directory list
 */
static void add_to_dirlist(const char *name, struct dir_list **list)
{
	struct dir_list *dp;

	dp = xmalloc(sizeof(struct dir_list));
	dp->name = xmalloc(strlen(name)+1);
	strcpy(dp->name, name);
	dp->next = *list;
	*list = dp;
}

/*
 * This function frees a directory list
 */
static void free_dirlist(struct dir_list **list)
{
	struct dir_list *dp, *next;

	for (dp = *list; dp; dp = next) {
		next = dp->next;
		free(dp->name);
		free(dp);
	}
	*list = 0;
}

static int scan_dir(char *dir_name, dev_t device, struct dir_list **list,
		    char **ret_path)
{
	DIR	*dir;
	struct dirent *dp;
	char	path[1024], *cp;
	int	dirlen;
	struct stat st;

	dirlen = strlen(dir_name);
	if ((dir = opendir(dir_name)) == NULL)
		return errno;
	dp = readdir(dir);
	while (dp) {
		if (dirlen + strlen(dp->d_name) + 2 >= sizeof(path))
			goto skip_to_next;
		if (dp->d_name[0] == '.' &&
		    ((dp->d_name[1] == 0) ||
		     ((dp->d_name[1] == '.') && (dp->d_name[2] == 0))))
			goto skip_to_next;
		sprintf(path, "%s/%s", dir_name, dp->d_name);
		if (stat(path, &st) < 0)
			goto skip_to_next;
		if (S_ISDIR(st.st_mode))
			add_to_dirlist(path, list);
		if (S_ISBLK(st.st_mode) && st.st_rdev == device) {
			cp = xmalloc(strlen(path)+1);
			strcpy(cp, path);
			*ret_path = cp;
			goto success;
		}
	skip_to_next:
		dp = readdir(dir);
	}
success:
	closedir(dir);
	return 0;
}

/*
 * This function finds the pathname to a block device with a given
 * device number.  It returns a pointer to allocated memory to the
 * pathname on success, and NULL on failure.
 */
char *ext2fs_find_block_device(dev_t device)
{
	struct dir_list *list = 0, *new_list = 0;
	struct dir_list *current;
	char	*ret_path = 0;

	/*
	 * Add the starting directories to search...
	 */
	add_to_dirlist("/devices", &list);
	add_to_dirlist("/devfs", &list);
	add_to_dirlist("/dev", &list);

	while (list) {
		current = list;
		list = list->next;
#ifdef DEBUG
		printf("Scanning directory %s\n", current->name);
#endif
		scan_dir(current->name, device, &new_list, &ret_path);
		free(current->name);
		free(current);
		if (ret_path)
			break;
		/*
		 * If we're done checking at this level, descend to
		 * the next level of subdirectories. (breadth-first)
		 */
		if (list == 0) {
			list = new_list;
			new_list = 0;
		}
	}
	free_dirlist(&list);
	free_dirlist(&new_list);
	return ret_path;
}


#ifdef DEBUG
int main(int argc, char** argv)
{
	char	*devname, *tmp;
	int	major, minor;
	dev_t	device;
	const char *errmsg = "Cannot parse %s: %s\n";

	if ((argc != 2) && (argc != 3)) {
		fprintf(stderr, "Usage: %s device_number\n", argv[0]);
		fprintf(stderr, "\t: %s major minor\n", argv[0]);
		exit(1);
	}
	if (argc == 2) {
		device = strtoul(argv[1], &tmp, 0);
		if (*tmp) {
			fprintf(stderr, errmsg, "device number", argv[1]);
			exit(1);
		}
	} else {
		major = strtoul(argv[1], &tmp, 0);
		if (*tmp) {
			fprintf(stderr, errmsg, "major number", argv[1]);
			exit(1);
		}
		minor = strtoul(argv[2], &tmp, 0);
		if (*tmp) {
			fprintf(stderr, errmsg, "minor number", argv[2]);
			exit(1);
		}
		device = makedev(major, minor);
		printf("Looking for device 0x%04x (%d:%d)\n", device,
		       major, minor);
	}
	devname = ext2fs_find_block_device(device);
	if (devname) {
		printf("Found device!  %s\n", devname);
		free(devname);
	} else {
		printf("Cannot find device.\n");
	}
	return 0;
}

#endif