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-rw-r--r--e2fsprogs/blkid/devno.c223
1 files changed, 223 insertions, 0 deletions
diff --git a/e2fsprogs/blkid/devno.c b/e2fsprogs/blkid/devno.c
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index 000000000..13e7f1a87
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1/* vi: set sw=4 ts=4: */
2/*
3 * devno.c - find a particular device by its device number (major/minor)
4 *
5 * Copyright (C) 2000, 2001, 2003 Theodore Ts'o
6 * Copyright (C) 2001 Andreas Dilger
7 *
8 * %Begin-Header%
9 * This file may be redistributed under the terms of the
10 * GNU Lesser General Public License.
11 * %End-Header%
12 */
13
14#include <stdio.h>
15#include <string.h>
16#ifdef HAVE_UNISTD_H
17#include <unistd.h>
18#endif
19#include <stdlib.h>
20#include <string.h>
21#ifdef HAVE_SYS_TYPES_H
22#include <sys/types.h>
23#endif
24#include <sys/stat.h>
25#include <dirent.h>
26#ifdef HAVE_ERRNO_H
27#include <errno.h>
28#endif
29#ifdef HAVE_SYS_MKDEV_H
30#include <sys/mkdev.h>
31#endif
32
33#include "blkidP.h"
34
35struct dir_list {
36 char *name;
37 struct dir_list *next;
38};
39
40char *blkid_strndup(const char *s, int length)
41{
42 char *ret;
43
44 if (!s)
45 return NULL;
46
47 if (!length)
48 length = strlen(s);
49
50 ret = xmalloc(length + 1);
51 strncpy(ret, s, length);
52 ret[length] = '\0';
53 return ret;
54}
55
56char *blkid_strdup(const char *s)
57{
58 return blkid_strndup(s, 0);
59}
60
61/*
62 * This function adds an entry to the directory list
63 */
64static void add_to_dirlist(const char *name, struct dir_list **list)
65{
66 struct dir_list *dp;
67
68 dp = xmalloc(sizeof(struct dir_list));
69 dp->name = blkid_strdup(name);
70 dp->next = *list;
71 *list = dp;
72}
73
74/*
75 * This function frees a directory list
76 */
77static void free_dirlist(struct dir_list **list)
78{
79 struct dir_list *dp, *next;
80
81 for (dp = *list; dp; dp = next) {
82 next = dp->next;
83 free(dp->name);
84 free(dp);
85 }
86 *list = NULL;
87}
88
89static void scan_dir(char *dir_name, dev_t devno, struct dir_list **list,
90 char **devname)
91{
92 DIR *dir;
93 struct dirent *dp;
94 char path[1024];
95 int dirlen;
96 struct stat st;
97
98 if ((dir = opendir(dir_name)) == NULL)
99 return;
100 dirlen = strlen(dir_name) + 2;
101 while ((dp = readdir(dir)) != 0) {
102 if (dirlen + strlen(dp->d_name) >= sizeof(path))
103 continue;
104
105 if (dp->d_name[0] == '.' &&
106 ((dp->d_name[1] == 0) ||
107 ((dp->d_name[1] == '.') && (dp->d_name[2] == 0))))
108 continue;
109
110 sprintf(path, "%s/%s", dir_name, dp->d_name);
111 if (stat(path, &st) < 0)
112 continue;
113
114 if (S_ISDIR(st.st_mode))
115 add_to_dirlist(path, list);
116 else if (S_ISBLK(st.st_mode) && st.st_rdev == devno) {
117 *devname = blkid_strdup(path);
118 DBG(DEBUG_DEVNO,
119 printf("found 0x%llx at %s (%p)\n", devno,
120 path, *devname));
121 break;
122 }
123 }
124 closedir(dir);
125 return;
126}
127
128/* Directories where we will try to search for device numbers */
129const char *blkid_devdirs[] = { "/devices", "/devfs", "/dev", NULL };
130
131/*
132 * This function finds the pathname to a block device with a given
133 * device number. It returns a pointer to allocated memory to the
134 * pathname on success, and NULL on failure.
135 */
136char *blkid_devno_to_devname(dev_t devno)
137{
138 struct dir_list *list = NULL, *new_list = NULL;
139 char *devname = NULL;
140 const char **dir;
141
142 /*
143 * Add the starting directories to search in reverse order of
144 * importance, since we are using a stack...
145 */
146 for (dir = blkid_devdirs; *dir; dir++)
147 add_to_dirlist(*dir, &list);
148
149 while (list) {
150 struct dir_list *current = list;
151
152 list = list->next;
153 DBG(DEBUG_DEVNO, printf("directory %s\n", current->name));
154 scan_dir(current->name, devno, &new_list, &devname);
155 free(current->name);
156 free(current);
157 if (devname)
158 break;
159 /*
160 * If we're done checking at this level, descend to
161 * the next level of subdirectories. (breadth-first)
162 */
163 if (list == NULL) {
164 list = new_list;
165 new_list = NULL;
166 }
167 }
168 free_dirlist(&list);
169 free_dirlist(&new_list);
170
171 if (!devname) {
172 DBG(DEBUG_DEVNO,
173 printf("blkid: cannot find devno 0x%04lx\n",
174 (unsigned long) devno));
175 } else {
176 DBG(DEBUG_DEVNO,
177 printf("found devno 0x%04llx as %s\n", devno, devname));
178 }
179
180
181 return devname;
182}
183
184#ifdef TEST_PROGRAM
185int main(int argc, char** argv)
186{
187 char *devname, *tmp;
188 int major, minor;
189 dev_t devno;
190 const char *errmsg = "Cannot parse %s: %s\n";
191
192 blkid_debug_mask = DEBUG_ALL;
193 if ((argc != 2) && (argc != 3)) {
194 fprintf(stderr, "Usage:\t%s device_number\n\t%s major minor\n"
195 "Resolve a device number to a device name\n",
196 argv[0], argv[0]);
197 exit(1);
198 }
199 if (argc == 2) {
200 devno = strtoul(argv[1], &tmp, 0);
201 if (*tmp) {
202 fprintf(stderr, errmsg, "device number", argv[1]);
203 exit(1);
204 }
205 } else {
206 major = strtoul(argv[1], &tmp, 0);
207 if (*tmp) {
208 fprintf(stderr, errmsg, "major number", argv[1]);
209 exit(1);
210 }
211 minor = strtoul(argv[2], &tmp, 0);
212 if (*tmp) {
213 fprintf(stderr, errmsg, "minor number", argv[2]);
214 exit(1);
215 }
216 devno = makedev(major, minor);
217 }
218 printf("Looking for device 0x%04Lx\n", devno);
219 devname = blkid_devno_to_devname(devno);
220 free(devname);
221 return 0;
222}
223#endif