2 * libudev - interface to udev device information
4 * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
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.
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.
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/>.
32 #include "libudev-private.h"
35 static ssize_t get_sys_link(struct udev *udev, const char *slink, const char *devpath, char *subsystem, size_t size)
41 strlcpy(path, udev_get_sys_path(udev), sizeof(path));
42 strlcat(path, devpath, sizeof(path));
43 strlcat(path, "/", sizeof(path));
44 strlcat(path, slink, sizeof(path));
45 len = readlink(path, path, sizeof(path));
46 if (len < 0 || len >= (ssize_t) sizeof(path))
49 pos = strrchr(path, '/');
53 return strlcpy(subsystem, pos, size);
56 ssize_t util_get_sys_subsystem(struct udev *udev, const char *devpath, char *subsystem, size_t size)
58 return get_sys_link(udev, "subsystem", devpath, subsystem, size);
61 ssize_t util_get_sys_driver(struct udev *udev, const char *devpath, char *driver, size_t size)
63 return get_sys_link(udev, "driver", devpath, driver, size);
66 int util_resolve_sys_link(struct udev *udev, char *devpath, size_t size)
68 char link_path[PATH_SIZE];
69 char link_target[PATH_SIZE];
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));
79 link_target[len] = '\0';
80 dbg(udev, "path link '%s' points to '%s'\n", devpath, link_target);
82 for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++)
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, '/');
92 dbg(udev, "after moving back '%s'\n", devpath);
93 strlcat(devpath, "/", size);
94 strlcat(devpath, &link_target[back * 3], size);