blob: e9e83fd7ad88c769ba761311cd88f7014d359dfd
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * finddev.c -- this routine attempts to find a particular device in |
4 | * /dev |
5 | * |
6 | * Copyright (C) 2000 Theodore Ts'o. |
7 | * |
8 | * %Begin-Header% |
9 | * This file may be redistributed under the terms of the GNU Public |
10 | * 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 | #ifdef HAVE_SYS_STAT_H |
25 | #include <sys/stat.h> |
26 | #endif |
27 | #include <dirent.h> |
28 | #ifdef HAVE_ERRNO_H |
29 | #include <errno.h> |
30 | #endif |
31 | #ifdef HAVE_SYS_MKDEV_H |
32 | #include <sys/mkdev.h> |
33 | #endif |
34 | |
35 | #include "ext2_fs.h" |
36 | #include "ext2fs.h" |
37 | |
38 | struct dir_list { |
39 | char *name; |
40 | struct dir_list *next; |
41 | }; |
42 | |
43 | /* |
44 | * This function adds an entry to the directory list |
45 | */ |
46 | static void add_to_dirlist(const char *name, struct dir_list **list) |
47 | { |
48 | struct dir_list *dp; |
49 | |
50 | dp = xmalloc(sizeof(struct dir_list)); |
51 | dp->name = xmalloc(strlen(name)+1); |
52 | strcpy(dp->name, name); |
53 | dp->next = *list; |
54 | *list = dp; |
55 | } |
56 | |
57 | /* |
58 | * This function frees a directory list |
59 | */ |
60 | static void free_dirlist(struct dir_list **list) |
61 | { |
62 | struct dir_list *dp, *next; |
63 | |
64 | for (dp = *list; dp; dp = next) { |
65 | next = dp->next; |
66 | free(dp->name); |
67 | free(dp); |
68 | } |
69 | *list = 0; |
70 | } |
71 | |
72 | static int scan_dir(char *dir_name, dev_t device, struct dir_list **list, |
73 | char **ret_path) |
74 | { |
75 | DIR *dir; |
76 | struct dirent *dp; |
77 | char path[1024], *cp; |
78 | int dirlen; |
79 | struct stat st; |
80 | |
81 | dirlen = strlen(dir_name); |
82 | if ((dir = opendir(dir_name)) == NULL) |
83 | return errno; |
84 | dp = readdir(dir); |
85 | while (dp) { |
86 | if (dirlen + strlen(dp->d_name) + 2 >= sizeof(path)) |
87 | goto skip_to_next; |
88 | if (dp->d_name[0] == '.' && |
89 | ((dp->d_name[1] == 0) || |
90 | ((dp->d_name[1] == '.') && (dp->d_name[2] == 0)))) |
91 | goto skip_to_next; |
92 | sprintf(path, "%s/%s", dir_name, dp->d_name); |
93 | if (stat(path, &st) < 0) |
94 | goto skip_to_next; |
95 | if (S_ISDIR(st.st_mode)) |
96 | add_to_dirlist(path, list); |
97 | if (S_ISBLK(st.st_mode) && st.st_rdev == device) { |
98 | cp = xmalloc(strlen(path)+1); |
99 | strcpy(cp, path); |
100 | *ret_path = cp; |
101 | goto success; |
102 | } |
103 | skip_to_next: |
104 | dp = readdir(dir); |
105 | } |
106 | success: |
107 | closedir(dir); |
108 | return 0; |
109 | } |
110 | |
111 | /* |
112 | * This function finds the pathname to a block device with a given |
113 | * device number. It returns a pointer to allocated memory to the |
114 | * pathname on success, and NULL on failure. |
115 | */ |
116 | char *ext2fs_find_block_device(dev_t device) |
117 | { |
118 | struct dir_list *list = NULL, *new_list = NULL; |
119 | struct dir_list *current; |
120 | char *ret_path = NULL; |
121 | |
122 | /* |
123 | * Add the starting directories to search... |
124 | */ |
125 | add_to_dirlist("/devices", &list); |
126 | add_to_dirlist("/devfs", &list); |
127 | add_to_dirlist("/dev", &list); |
128 | |
129 | while (list) { |
130 | current = list; |
131 | list = list->next; |
132 | #ifdef DEBUG |
133 | printf("Scanning directory %s\n", current->name); |
134 | #endif |
135 | scan_dir(current->name, device, &new_list, &ret_path); |
136 | free(current->name); |
137 | free(current); |
138 | if (ret_path) |
139 | break; |
140 | /* |
141 | * If we're done checking at this level, descend to |
142 | * the next level of subdirectories. (breadth-first) |
143 | */ |
144 | if (list == 0) { |
145 | list = new_list; |
146 | new_list = 0; |
147 | } |
148 | } |
149 | free_dirlist(&list); |
150 | free_dirlist(&new_list); |
151 | return ret_path; |
152 | } |
153 | |
154 | |
155 | #ifdef DEBUG |
156 | int main(int argc, char** argv) |
157 | { |
158 | char *devname, *tmp; |
159 | int major, minor; |
160 | dev_t device; |
161 | const char *errmsg = "Cannot parse %s: %s\n"; |
162 | |
163 | if ((argc != 2) && (argc != 3)) { |
164 | fprintf(stderr, "Usage: %s device_number\n", argv[0]); |
165 | fprintf(stderr, "\t: %s major minor\n", argv[0]); |
166 | exit(1); |
167 | } |
168 | if (argc == 2) { |
169 | device = strtoul(argv[1], &tmp, 0); |
170 | if (*tmp) { |
171 | fprintf(stderr, errmsg, "device number", argv[1]); |
172 | exit(1); |
173 | } |
174 | } else { |
175 | major = strtoul(argv[1], &tmp, 0); |
176 | if (*tmp) { |
177 | fprintf(stderr, errmsg, "major number", argv[1]); |
178 | exit(1); |
179 | } |
180 | minor = strtoul(argv[2], &tmp, 0); |
181 | if (*tmp) { |
182 | fprintf(stderr, errmsg, "minor number", argv[2]); |
183 | exit(1); |
184 | } |
185 | device = makedev(major, minor); |
186 | printf("Looking for device 0x%04x (%d:%d)\n", device, |
187 | major, minor); |
188 | } |
189 | devname = ext2fs_find_block_device(device); |
190 | if (devname) { |
191 | printf("Found device! %s\n", devname); |
192 | free(devname); |
193 | } else { |
194 | printf("Cannot find device.\n"); |
195 | } |
196 | return 0; |
197 | } |
198 | |
199 | #endif |
200 |