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
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
|
/* vi: set sw=4 ts=4: */
/*
* devno.c - find a particular device by its device number (major/minor)
*
* Copyright (C) 2000, 2001, 2003 Theodore Ts'o
* Copyright (C) 2001 Andreas Dilger
*
* %Begin-Header%
* This file may be redistributed under the terms of the
* GNU Lesser General 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
#include <sys/stat.h>
#include <dirent.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_SYS_MKDEV_H
#include <sys/mkdev.h>
#endif
#include "blkidP.h"
struct dir_list {
char *name;
struct dir_list *next;
};
char *blkid_strndup(const char *s, int length)
{
char *ret;
if (!s)
return NULL;
if (!length)
length = strlen(s);
ret = xmalloc(length + 1);
strncpy(ret, s, length);
ret[length] = '\0';
return ret;
}
char *blkid_strdup(const char *s)
{
return blkid_strndup(s, 0);
}
/*
* 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 = blkid_strdup(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 = NULL;
}
static void scan_dir(char *dir_name, dev_t devno, struct dir_list **list,
char **devname)
{
DIR *dir;
struct dirent *dp;
char path[1024];
int dirlen;
struct stat st;
if ((dir = opendir(dir_name)) == NULL)
return;
dirlen = strlen(dir_name) + 2;
while ((dp = readdir(dir)) != 0) {
if (dirlen + strlen(dp->d_name) >= sizeof(path))
continue;
if (dp->d_name[0] == '.' &&
((dp->d_name[1] == 0) ||
((dp->d_name[1] == '.') && (dp->d_name[2] == 0))))
continue;
sprintf(path, "%s/%s", dir_name, dp->d_name);
if (stat(path, &st) < 0)
continue;
if (S_ISDIR(st.st_mode))
add_to_dirlist(path, list);
else if (S_ISBLK(st.st_mode) && st.st_rdev == devno) {
*devname = blkid_strdup(path);
DBG(DEBUG_DEVNO,
printf("found 0x%llx at %s (%p)\n", devno,
path, *devname));
break;
}
}
closedir(dir);
return;
}
/* Directories where we will try to search for device numbers */
const char *blkid_devdirs[] = { "/devices", "/devfs", "/dev", NULL };
/*
* 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 *blkid_devno_to_devname(dev_t devno)
{
struct dir_list *list = NULL, *new_list = NULL;
char *devname = NULL;
const char **dir;
/*
* Add the starting directories to search in reverse order of
* importance, since we are using a stack...
*/
for (dir = blkid_devdirs; *dir; dir++)
add_to_dirlist(*dir, &list);
while (list) {
struct dir_list *current = list;
list = list->next;
DBG(DEBUG_DEVNO, printf("directory %s\n", current->name));
scan_dir(current->name, devno, &new_list, &devname);
free(current->name);
free(current);
if (devname)
break;
/*
* If we're done checking at this level, descend to
* the next level of subdirectories. (breadth-first)
*/
if (list == NULL) {
list = new_list;
new_list = NULL;
}
}
free_dirlist(&list);
free_dirlist(&new_list);
if (!devname) {
DBG(DEBUG_DEVNO,
printf("blkid: cannot find devno 0x%04lx\n",
(unsigned long) devno));
} else {
DBG(DEBUG_DEVNO,
printf("found devno 0x%04llx as %s\n", devno, devname));
}
return devname;
}
#ifdef TEST_PROGRAM
int main(int argc, char** argv)
{
char *devname, *tmp;
int major, minor;
dev_t devno;
const char *errmsg = "Cannot parse %s: %s\n";
blkid_debug_mask = DEBUG_ALL;
if ((argc != 2) && (argc != 3)) {
fprintf(stderr, "Usage:\t%s device_number\n\t%s major minor\n"
"Resolve a device number to a device name\n",
argv[0], argv[0]);
exit(1);
}
if (argc == 2) {
devno = 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);
}
devno = makedev(major, minor);
}
printf("Looking for device 0x%04Lx\n", devno);
devname = blkid_devno_to_devname(devno);
free(devname);
return 0;
}
#endif
|
