1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2020 Emmanuel Vadot <[email protected]>
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/capsicum.h>
34 #include <sys/backlight.h>
35
36 #include <err.h>
37 #include <errno.h>
38 #include <fcntl.h>
39 #include <limits.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <unistd.h>
44 #include <capsicum_helpers.h>
45
46 #define BACKLIGHT_QUERY 0x0001
47 #define BACKLIGHT_SET_BRIGHTNESS 0x0002
48 #define BACKLIGHT_INCR 0x0004
49 #define BACKLIGHT_DECR 0x0008
50 #define BACKLIGHT_INFO 0x0010
51
52 static char device_name[PATH_MAX] = "/dev/backlight/backlight0";
53
54 static void
set_device_name(const char * name)55 set_device_name(const char *name)
56 {
57
58 if (name[0] == '/')
59 strlcpy(device_name, name, sizeof(device_name));
60 else
61 snprintf(device_name, sizeof(device_name), "/dev/backlight/%s", name);
62 }
63
64 static void
usage(void)65 usage(void)
66 {
67 fprintf(stderr, "Usage:\n");
68 fprintf(stderr, "\tbacklight [-f dev]\n");
69 fprintf(stderr, "\tbacklight [-f dev] -i\n");
70 fprintf(stderr, "\tbacklight [-f dev] <percent>\n");
71 fprintf(stderr, "\tbacklight [-f dev] incr|+ <percent>\n");
72 fprintf(stderr, "\tbacklight [-f dev] decr|- <percent>\n");
73 exit(1);
74 }
75
76 static const char *
backlight_type_to_string(enum backlight_info_type type)77 backlight_type_to_string(enum backlight_info_type type)
78 {
79 switch (type) {
80 case BACKLIGHT_TYPE_PANEL:
81 return ("Panel");
82 case BACKLIGHT_TYPE_KEYBOARD:
83 return ("Keyboard");
84 }
85
86 return ("Unknown");
87 }
88
89 int
main(int argc,char * argv[])90 main(int argc, char *argv[])
91 {
92 struct backlight_props props;
93 struct backlight_info info;
94 int fd;
95 int action, ch;
96 cap_rights_t right_ioctl;
97 const unsigned long backlight_ioctls[] = {
98 BACKLIGHTGETSTATUS,
99 BACKLIGHTUPDATESTATUS,
100 BACKLIGHTGETINFO};
101 long percent = -1;
102 const char *percent_error;
103 uint32_t i;
104 bool setname;
105 bool quiet = false;
106
107 action = BACKLIGHT_QUERY;
108 setname = false;
109 fd = -1;
110
111 while ((ch = getopt(argc, argv, "f:qhi")) != -1) {
112 switch (ch) {
113 case 'q':
114 quiet = true;
115 break;
116 case 'f':
117 setname = true;
118 set_device_name(optarg);
119 break;
120 case 'i':
121 action = BACKLIGHT_INFO;
122 break;
123 case 'h':
124 usage();
125 break;
126 }
127 }
128
129 argc -= optind;
130 argv += optind;
131 if (argc != 0) {
132 if (strcmp("incr", argv[0]) == 0 ||
133 strcmp("+", argv[0]) == 0) {
134 action = BACKLIGHT_INCR;
135 argc -= 1;
136 argv += 1;
137 }
138 else if (strcmp("decr", argv[0]) == 0 ||
139 strcmp("-", argv[0]) == 0) {
140 action = BACKLIGHT_DECR;
141 argc -= 1;
142 argv += 1;
143 } else
144 action = BACKLIGHT_SET_BRIGHTNESS;
145
146 if (argc == 1) {
147 /* ignore a trailing % for user friendlyness */
148 if (strlen(argv[0]) > 0 &&
149 argv[0][strlen(argv[0]) - 1] == '%')
150 argv[0][strlen(argv[0]) - 1] = '\0';
151 percent = strtonum(argv[0], 0, 100, &percent_error);
152 if (percent_error)
153 errx(1, "Cannot parse brightness level %s: %s",
154 argv[0],
155 percent_error);
156 }
157 }
158
159 if ((fd = open(device_name, O_RDWR)) == -1)
160 errx(1, "cannot open %s: %s",
161 device_name, strerror(errno));
162
163 if (caph_limit_stdio() < 0)
164 errx(1, "can't limit stdio rights");
165 caph_cache_catpages();
166 cap_rights_init(&right_ioctl, CAP_IOCTL);
167 if (caph_rights_limit(fd, &right_ioctl) < 0)
168 errx(1, "cap_right_limit() failed");
169 if (caph_ioctls_limit(fd, backlight_ioctls, nitems(backlight_ioctls)) < 0)
170 errx(1, "caph_ioctls_limit() failed");
171 if (caph_enter() < 0)
172 errx(1, "failed to enter capability mode");
173
174 switch (action) {
175 case BACKLIGHT_QUERY:
176 if (ioctl(fd, BACKLIGHTGETSTATUS, &props) == -1)
177 errx(1, "Cannot query the backlight device");
178 if (quiet)
179 printf("%u\n", props.brightness);
180 else {
181 printf("brightness: %d\n", props.brightness);
182 if (props.nlevels != 0) {
183 printf("levels:");
184 for (i = 0; i < props.nlevels; i++)
185 printf(" %d", props.levels[i]);
186 printf("\n");
187 }
188 }
189 break;
190 case BACKLIGHT_SET_BRIGHTNESS:
191 if (percent == -1)
192 usage();
193 props.brightness = percent;
194 if (ioctl(fd, BACKLIGHTUPDATESTATUS, &props) == -1)
195 errx(1, "Cannot update the backlight device");
196 break;
197 case BACKLIGHT_INCR:
198 case BACKLIGHT_DECR:
199 if (percent == 0)
200 /* Avoid any ioctl if we don't have anything to do */
201 break;
202 if (ioctl(fd, BACKLIGHTGETSTATUS, &props) == -1)
203 errx(1, "Cannot query the backlight device");
204 percent = percent == -1 ? 10 : percent;
205 percent = action == BACKLIGHT_INCR ? percent : -percent;
206 props.brightness += percent;
207 if ((int)props.brightness < 0)
208 props.brightness = 0;
209 if (props.brightness > 100)
210 props.brightness = 100;
211 if (ioctl(fd, BACKLIGHTUPDATESTATUS, &props) == -1)
212 errx(1, "Cannot update the backlight device");
213 break;
214 case BACKLIGHT_INFO:
215 if (ioctl(fd, BACKLIGHTGETINFO, &info) == -1)
216 errx(1, "Cannot query the backlight device");
217 if (quiet == false) {
218 printf("Backlight name: %s\n", info.name);
219 printf("Backlight hardware type: %s\n", backlight_type_to_string(info.type));
220 } else {
221 printf("%s\n", info.name);
222 printf("%s\n", backlight_type_to_string(info.type));
223 }
224 break;
225 }
226
227 close(fd);
228 return (0);
229 }
230