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eb1f0e66 KS |
1 | /* |
2 | * libudev - interface to udev device information | |
3 | * | |
4 | * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org> | |
5 | * | |
6 | * This program is free software: you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation, either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include "config.h" | |
21 | ||
22 | #include <stdio.h> | |
23 | #include <stdlib.h> | |
24 | #include <stddef.h> | |
25 | #include <unistd.h> | |
26 | #include <errno.h> | |
27 | #include <string.h> | |
28 | #include <dirent.h> | |
29 | #include <sys/stat.h> | |
30 | ||
31 | #include "libudev.h" | |
32 | #include "libudev-private.h" | |
33 | #include "../udev.h" | |
34 | ||
95d90c4f | 35 | static ssize_t get_sys_link(struct udev *udev, const char *slink, const char *devpath, char *subsystem, size_t size) |
eb1f0e66 KS |
36 | { |
37 | char path[PATH_SIZE]; | |
38 | ssize_t len; | |
39 | const char *pos; | |
40 | ||
41 | strlcpy(path, udev_get_sys_path(udev), sizeof(path)); | |
42 | strlcat(path, devpath, sizeof(path)); | |
95d90c4f KS |
43 | strlcat(path, "/", sizeof(path)); |
44 | strlcat(path, slink, sizeof(path)); | |
eb1f0e66 KS |
45 | len = readlink(path, path, sizeof(path)); |
46 | if (len < 0 || len >= (ssize_t) sizeof(path)) | |
47 | return -1; | |
48 | path[len] = '\0'; | |
49 | pos = strrchr(path, '/'); | |
50 | if (pos == NULL) | |
51 | return -1; | |
52 | pos = &pos[1]; | |
53 | return strlcpy(subsystem, pos, size); | |
54 | } | |
95d90c4f KS |
55 | |
56 | ssize_t util_get_sys_subsystem(struct udev *udev, const char *devpath, char *subsystem, size_t size) | |
57 | { | |
58 | return get_sys_link(udev, "subsystem", devpath, subsystem, size); | |
59 | } | |
60 | ||
61 | ssize_t util_get_sys_driver(struct udev *udev, const char *devpath, char *driver, size_t size) | |
62 | { | |
63 | return get_sys_link(udev, "driver", devpath, driver, size); | |
64 | } | |
65 | ||
b21b95d7 KS |
66 | int util_resolve_sys_link(struct udev *udev, char *devpath, size_t size) |
67 | { | |
68 | char link_path[PATH_SIZE]; | |
69 | char link_target[PATH_SIZE]; | |
70 | int len; | |
71 | int i; | |
72 | int back; | |
73 | ||
74 | strlcpy(link_path, udev_get_sys_path(udev), sizeof(link_path)); | |
75 | strlcat(link_path, devpath, sizeof(link_path)); | |
76 | len = readlink(link_path, link_target, sizeof(link_target)); | |
77 | if (len <= 0) | |
78 | return -1; | |
79 | link_target[len] = '\0'; | |
80 | dbg(udev, "path link '%s' points to '%s'\n", devpath, link_target); | |
81 | ||
82 | for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++) | |
83 | ; | |
84 | dbg(udev, "base '%s', tail '%s', back %i\n", devpath, &link_target[back * 3], back); | |
85 | for (i = 0; i <= back; i++) { | |
86 | char *pos = strrchr(devpath, '/'); | |
87 | ||
88 | if (pos == NULL) | |
89 | return -1; | |
90 | pos[0] = '\0'; | |
91 | } | |
92 | dbg(udev, "after moving back '%s'\n", devpath); | |
93 | strlcat(devpath, "/", size); | |
94 | strlcat(devpath, &link_target[back * 3], size); | |
95 | return 0; | |
96 | } |