blob: 8436cd664fcb28091299126baf82dfc5e3a59c4d
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Utility routines. |
4 | * |
5 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> |
6 | * |
7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
8 | */ |
9 | |
10 | #include "libbb.h" |
11 | |
12 | /* Find block device /dev/XXX which contains specified file |
13 | * We handle /dev/dir/dir/dir too, at a cost of ~80 more bytes code */ |
14 | |
15 | /* Do not reallocate all this stuff on each recursion */ |
16 | enum { DEVNAME_MAX = 256 }; |
17 | struct arena { |
18 | struct stat st; |
19 | dev_t dev; |
20 | /* Was PATH_MAX, but we recurse _/dev_. We can assume |
21 | * people are not crazy enough to have mega-deep tree there */ |
22 | char devpath[DEVNAME_MAX]; |
23 | }; |
24 | |
25 | static char *find_block_device_in_dir(struct arena *ap) |
26 | { |
27 | DIR *dir; |
28 | struct dirent *entry; |
29 | char *retpath = NULL; |
30 | int len, rem; |
31 | |
32 | len = strlen(ap->devpath); |
33 | rem = DEVNAME_MAX-2 - len; |
34 | if (rem <= 0) |
35 | return NULL; |
36 | |
37 | dir = opendir(ap->devpath); |
38 | if (!dir) |
39 | return NULL; |
40 | |
41 | ap->devpath[len++] = '/'; |
42 | |
43 | while ((entry = readdir(dir)) != NULL) { |
44 | safe_strncpy(ap->devpath + len, entry->d_name, rem); |
45 | /* lstat: do not follow links */ |
46 | if (lstat(ap->devpath, &ap->st) != 0) |
47 | continue; |
48 | if (S_ISBLK(ap->st.st_mode) && ap->st.st_rdev == ap->dev) { |
49 | retpath = xstrdup(ap->devpath); |
50 | break; |
51 | } |
52 | if (S_ISDIR(ap->st.st_mode)) { |
53 | /* Do not recurse for '.' and '..' */ |
54 | if (DOT_OR_DOTDOT(entry->d_name)) |
55 | continue; |
56 | retpath = find_block_device_in_dir(ap); |
57 | if (retpath) |
58 | break; |
59 | } |
60 | } |
61 | closedir(dir); |
62 | |
63 | return retpath; |
64 | } |
65 | |
66 | char* FAST_FUNC find_block_device(const char *path) |
67 | { |
68 | struct arena a; |
69 | |
70 | if (stat(path, &a.st) != 0) |
71 | return NULL; |
72 | a.dev = S_ISBLK(a.st.st_mode) ? a.st.st_rdev : a.st.st_dev; |
73 | strcpy(a.devpath, "/dev"); |
74 | return find_block_device_in_dir(&a); |
75 | } |
76 |