/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2020 Emmanuel Vadot <manu@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/types.h>
#include <sys/ioctl.h>
#include <stdbool.h>
#include <sys/capsicum.h>
#include <sys/backlight.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <capsicum_helpers.h>
#define BACKLIGHT_QUERY 0x0001
#define BACKLIGHT_SET_BRIGHTNESS 0x0002
#define BACKLIGHT_INCR 0x0004
#define BACKLIGHT_DECR 0x0008
#define BACKLIGHT_INFO 0x0010
static char device_name[PATH_MAX] = "/dev/backlight/backlight0";
static void
set_device_name(const char *name)
{
if (name[0] == '/')
strlcpy(device_name, name, sizeof(device_name));
else
snprintf(device_name, sizeof(device_name), "/dev/backlight/%s", name);
}
static void
usage(void)
{
fprintf(stderr, "Usage:\n");
fprintf(stderr, "\tbacklight [-f dev]\n");
fprintf(stderr, "\tbacklight [-f dev] -i\n");
fprintf(stderr, "\tbacklight [-f dev] <percent>\n");
fprintf(stderr, "\tbacklight [-f dev] incr|+ <percent>\n");
fprintf(stderr, "\tbacklight [-f dev] decr|- <percent>\n");
exit(1);
}
static const char *
backlight_type_to_string(enum backlight_info_type type)
{
switch (type) {
case BACKLIGHT_TYPE_PANEL:
return ("Panel");
case BACKLIGHT_TYPE_KEYBOARD:
return ("Keyboard");
}
return ("Unknown");
}
int
main(int argc, char *argv[])
{
struct backlight_props props;
struct backlight_info info;
int fd;
int action, ch;
cap_rights_t right_ioctl;
const unsigned long backlight_ioctls[] = {
BACKLIGHTGETSTATUS,
BACKLIGHTUPDATESTATUS,
BACKLIGHTGETINFO};
long percent = 0;
const char *percent_error;
uint32_t i;
bool setname;
bool quiet = false;
action = BACKLIGHT_QUERY;
setname = false;
fd = -1;
while ((ch = getopt(argc, argv, "f:qhi")) != -1) {
switch (ch) {
case 'q':
quiet = true;
break;
case 'f':
setname = true;
set_device_name(optarg);
break;
case 'i':
action = BACKLIGHT_INFO;
break;
case 'h':
usage();
break;
}
}
argc -= optind;
argv += optind;
if (argc != 0) {
if (strcmp("incr", argv[0]) == 0 ||
strcmp("+", argv[0]) == 0) {
action = BACKLIGHT_INCR;
argc -= 1;
argv += 1;
}
else if (strcmp("decr", argv[0]) == 0 ||
strcmp("-", argv[0]) == 0) {
action = BACKLIGHT_DECR;
argc -= 1;
argv += 1;
} else
action = BACKLIGHT_SET_BRIGHTNESS;
if (argc == 1) {
/* ignore a trailing % for user friendlyness */
if (strlen(argv[0]) > 0 &&
argv[0][strlen(argv[0]) - 1] == '%')
argv[0][strlen(argv[0]) - 1] = '\0';
percent = strtonum(argv[0], 0, 100, &percent_error);
if (percent_error)
errx(1, "Cannot parse brightness level %s: %s",
argv[0],
percent_error);
}
}
if ((fd = open(device_name, O_RDWR)) == -1)
errx(1, "cannot open %s: %s",
device_name, strerror(errno));
if (caph_limit_stdio() < 0)
errx(1, "can't limit stdio rights");
caph_cache_catpages();
cap_rights_init(&right_ioctl, CAP_IOCTL);
if (caph_rights_limit(fd, &right_ioctl) < 0)
errx(1, "cap_right_limit() failed");
if (caph_ioctls_limit(fd, backlight_ioctls, nitems(backlight_ioctls)) < 0)
errx(1, "caph_ioctls_limit() failed");
if (caph_enter() < 0)
errx(1, "failed to enter capability mode");
switch (action) {
case BACKLIGHT_QUERY:
if (ioctl(fd, BACKLIGHTGETSTATUS, &props) == -1)
errx(1, "Cannot query the backlight device");
if (quiet)
printf("%u\n", props.brightness);
else {
printf("brightness: %d\n", props.brightness);
if (props.nlevels != 0) {
printf("levels:");
for (i = 0; i < props.nlevels; i++)
printf(" %d", props.levels[i]);
printf("\n");
}
}
break;
case BACKLIGHT_SET_BRIGHTNESS:
props.brightness = percent;
if (ioctl(fd, BACKLIGHTUPDATESTATUS, &props) == -1)
errx(1, "Cannot update the backlight device");
break;
case BACKLIGHT_INCR:
case BACKLIGHT_DECR:
if (ioctl(fd, BACKLIGHTGETSTATUS, &props) == -1)
errx(1, "Cannot query the backlight device");
percent = percent == 0 ? 10 : percent;
percent = action == BACKLIGHT_INCR ? percent : -percent;
props.brightness += percent;
if ((int)props.brightness < 0)
props.brightness = 0;
if (props.brightness > 100)
props.brightness = 100;
if (ioctl(fd, BACKLIGHTUPDATESTATUS, &props) == -1)
errx(1, "Cannot update the backlight device");
break;
case BACKLIGHT_INFO:
if (ioctl(fd, BACKLIGHTGETINFO, &info) == -1)
errx(1, "Cannot query the backlight device");
if (quiet == false) {
printf("Backlight name: %s\n", info.name);
printf("Backlight hardware type: %s\n", backlight_type_to_string(info.type));
} else {
printf("%s\n", info.name);
printf("%s\n", backlight_type_to_string(info.type));
}
break;
}
close(fd);
return (0);
}
