1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2013 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
28 int main(int argc, char *argv[]) {
29 struct udev *udev = NULL;
30 struct udev_device *device = NULL;
31 _cleanup_free_ char *saved = NULL;
35 log_error("This program requires two arguments.");
39 log_set_target(LOG_TARGET_AUTO);
40 log_parse_environment();
45 r = mkdir_p("/var/lib/systemd/backlight", 0755);
47 log_error("Failed to create backlight directory: %s", strerror(-r));
58 device = udev_device_new_from_subsystem_sysname(udev, "backlight", argv[2]);
60 device = udev_device_new_from_subsystem_sysname(udev, "leds", argv[2]);
63 log_error("Failed to get backlight device '%s': %m", argv[2]);
71 if (!streq_ptr(udev_device_get_subsystem(device), "backlight") &&
72 !streq_ptr(udev_device_get_subsystem(device), "leds")) {
73 log_error("Not a backlight device: %s", argv[2]);
78 saved = strappend("/var/lib/systemd/backlight/", udev_device_get_sysname(device));
84 if (streq(argv[1], "load")) {
85 _cleanup_free_ char *value = NULL;
87 r = read_one_line_file(saved, &value);
95 log_error("Failed to read %s: %s", saved, strerror(-r));
99 r = udev_device_set_sysattr_value(device, "brightness", value);
101 log_error("Failed to write system attribute: %s", strerror(-r));
105 } else if (streq(argv[1], "save")) {
108 value = udev_device_get_sysattr_value(device, "brightness");
110 log_error("Failed to read system attribute: %s", strerror(-r));
114 r = write_string_file(saved, value);
116 log_error("Failed to write %s: %s", saved, strerror(-r));
121 log_error("Unknown verb %s.", argv[1]);
128 udev_device_unref(device);
133 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;