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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <libudev.h>
#include "util.h"
#include "mkdir.h"
#include "fileio.h"
int main(int argc, char *argv[]) {
struct udev *udev = NULL;
struct udev_device *device = NULL;
_cleanup_free_ char *saved = NULL;
int r;
if (argc != 3) {
log_error("This program requires two arguments.");
return EXIT_FAILURE;
}
log_set_target(LOG_TARGET_AUTO);
log_parse_environment();
log_open();
umask(0022);
r = mkdir_p("/var/lib/backlight", 0755);
if (r < 0) {
log_error("Failed to create backlight directory: %s", strerror(-r));
goto finish;
}
udev = udev_new();
if (!udev) {
r = log_oom();
goto finish;
}
errno = 0;
device = udev_device_new_from_subsystem_sysname(udev, "backlight", argv[2]);
if (!device) {
if (errno != 0) {
log_error("Failed to get backlight device: %m");
r = -errno;
} else
r = log_oom();
goto finish;
}
if (!streq_ptr(udev_device_get_subsystem(device), "backlight")) {
log_error("Not a backlight device: %s", argv[2]);
r = -ENODEV;
goto finish;
}
saved = strappend("/var/lib/backlight/", udev_device_get_sysname(device));
if (!saved) {
r = log_oom();
goto finish;
}
if (streq(argv[1], "load")) {
_cleanup_free_ char *value = NULL;
r = read_one_line_file(saved, &value);
if (r < 0) {
if (r == -ENOENT) {
r = 0;
goto finish;
}
log_error("Failed to read %s: %s", saved, strerror(-r));
goto finish;
}
r = udev_device_set_sysattr_value(device, "brightness", value);
if (r < 0) {
log_error("Failed to write system attribute: %s", strerror(-r));
goto finish;
}
} else if (streq(argv[1], "save")) {
const char *value;
value = udev_device_get_sysattr_value(device, "brightness");
if (!value) {
log_error("Failed to read system attribute: %s", strerror(-r));
goto finish;
}
r = write_string_file(saved, value);
if (r < 0) {
log_error("Failed to write %s: %s", saved, strerror(-r));
goto finish;
}
} else {
log_error("Unknown verb %s.", argv[1]);
r = -EINVAL;
goto finish;
}
finish:
if (device)
udev_device_unref(device);
if (udev)
udev_unref(udev);
return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}
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