usr.bin/backlight/backlight.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2020 Emmanuel Vadot <manu@FreeBSD.org>
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  *
  27  * $FreeBSD$
  28  */
  29
  30 #include <sys/types.h>
  31 #include <sys/ioctl.h>
  32 #include <stdbool.h>
  33 #include <sys/backlight.h>
  34
  35 #include <err.h>
  36 #include <errno.h>
  37 #include <fcntl.h>
  38 #include <limits.h>
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include <unistd.h>
  43
  44 #define BACKLIGHT_QUERY                 0x0001
  45 #define BACKLIGHT_SET_BRIGHTNESS        0x0002
  46 #define BACKLIGHT_INCR                  0x0004
  47 #define BACKLIGHT_DECR                  0x0008
  48 #define BACKLIGHT_INFO                  0x0010
  49
  50 static char device_name[PATH_MAX] = "/dev/backlight/backlight0";
  51
  52 static void
  53 set_device_name(const char *name)
  54 {
  55
  56         if (name[0] == '/')
  57                 strlcpy(device_name, name, sizeof(device_name));
  58         else
  59                 snprintf(device_name, sizeof(device_name), "/dev/backlight/%s", name);
  60 }
  61
  62 static void
  63 usage(void)
  64 {
  65         fprintf(stderr, "Usage:\n");
  66         fprintf(stderr, "\tbacklight [-q] [-f device]\n");
  67         fprintf(stderr, "\tbacklight [-q] [-f device] -i\n");
  68         fprintf(stderr, "\tbacklight [-f device] value\n");
  69         fprintf(stderr, "\tbacklight [-f device] incr|+ value\n");
  70         fprintf(stderr, "\tbacklight [-f device] decr|- value\n");
  71         exit(1);
  72 }
  73
  74 static const char *
  75 backlight_type_to_string(enum backlight_info_type type)
  76 {
  77         switch (type) {
  78         case BACKLIGHT_TYPE_PANEL:
  79                 return ("Panel");
  80         case BACKLIGHT_TYPE_KEYBOARD:
  81                 return ("Keyboard");
  82         }
  83
  84         return ("Unknown");
  85 }
  86
  87 int
  88 main(int argc, char *argv[])
  89 {
  90         struct backlight_props props;
  91         struct backlight_info info;
  92         int fd;
  93         int action, ch;
  94         long percent = -1;
  95         const char *percent_error;
  96         uint32_t i;
  97         bool quiet = false;
  98
  99         action = BACKLIGHT_QUERY;
 100         fd = -1;
 101
 102         while ((ch = getopt(argc, argv, "f:qhi")) != -1) {
 103                 switch (ch) {
 104                 case 'q':
 105                         quiet = true;
 106                         break;
 107                 case 'f':
 108                         set_device_name(optarg);
 109                         break;
 110                 case 'i':
 111                         action = BACKLIGHT_INFO;
 112                         break;
 113                 case 'h':
 114                         usage();
 115                         break;
 116                 }
 117         }
 118
 119         argc -= optind;
 120         argv += optind;
 121         if (argc != 0) {
 122                 if (strcmp("incr", argv[0]) == 0 ||
 123                     strcmp("+", argv[0]) == 0) {
 124                         action = BACKLIGHT_INCR;
 125                         argc -= 1;
 126                         argv += 1;
 127                 }
 128                 else if (strcmp("decr", argv[0]) == 0 ||
 129                     strcmp("-", argv[0]) == 0) {
 130                         action = BACKLIGHT_DECR;
 131                         argc -= 1;
 132                         argv += 1;
 133                 } else
 134                         action = BACKLIGHT_SET_BRIGHTNESS;
 135
 136                 if (argc == 1) {
 137                         /* ignore a trailing % for user friendlyness */
 138                         if (strlen(argv[0]) > 0 &&
 139                             argv[0][strlen(argv[0]) - 1] == '%')
 140                                 argv[0][strlen(argv[0]) - 1] = '\0';
 141                         percent = strtonum(argv[0], 0, 100, &percent_error);
 142                         if (percent_error)
 143                                 errx(1, "Cannot parse brightness level %s: %s",
 144                                     argv[0],
 145                                     percent_error);
 146                 }
 147         }
 148
 149         if ((fd = open(device_name, O_RDWR)) == -1)
 150                 errx(1, "cannot open %s: %s",
 151                     device_name, strerror(errno));
 152
 153         switch (action) {
 154         case BACKLIGHT_QUERY:
 155                 if (ioctl(fd, BACKLIGHTGETSTATUS, &props) == -1)
 156                         errx(1, "Cannot query the backlight device");
 157                 if (quiet)
 158                         printf("%u\n", props.brightness);
 159                 else {
 160                         printf("brightness: %d\n", props.brightness);
 161                         if (props.nlevels != 0) {
 162                                 printf("levels:");
 163                                 for (i = 0; i < props.nlevels; i++)
 164                                         printf(" %d", props.levels[i]);
 165                                 printf("\n");
 166                         }
 167                 }
 168                 break;
 169         case BACKLIGHT_SET_BRIGHTNESS:
 170                 if (percent == -1)
 171                         usage();
 172                 props.brightness = percent;
 173                 if (ioctl(fd, BACKLIGHTUPDATESTATUS, &props) == -1)
 174                         errx(1, "Cannot update the backlight device");
 175                 break;
 176         case BACKLIGHT_INCR:
 177         case BACKLIGHT_DECR:
 178                 if (percent == 0)
 179                         /* Avoid any ioctl if we don't have anything to do */
 180                         break;
 181                 if (ioctl(fd, BACKLIGHTGETSTATUS, &props) == -1)
 182                         errx(1, "Cannot query the backlight device");
 183                 percent = percent == -1 ? 10 : percent;
 184                 percent = action == BACKLIGHT_INCR ? percent : -percent;
 185                 props.brightness += percent;
 186                 if ((int)props.brightness < 0)
 187                         props.brightness = 0;
 188                 if (props.brightness > 100)
 189                         props.brightness = 100;
 190                 if (ioctl(fd, BACKLIGHTUPDATESTATUS, &props) == -1)
 191                         errx(1, "Cannot update the backlight device");
 192                 break;
 193         case BACKLIGHT_INFO:
 194                 if (ioctl(fd, BACKLIGHTGETINFO, &info) == -1)
 195                         errx(1, "Cannot query the backlight device");
 196                 if (quiet == false) {
 197                         printf("Backlight name: %s\n", info.name);
 198                         printf("Backlight hardware type: %s\n", backlight_type_to_string(info.type));
 199                 } else {
 200                         printf("%s\n", info.name);
 201                         printf("%s\n", backlight_type_to_string(info.type));
 202                 }
 203                 break;
 204         }
 205
 206         close(fd);
 207         return (0);
 208 }