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-rw-r--r--adjbacklight.c425
1 files changed, 425 insertions, 0 deletions
diff --git a/adjbacklight.c b/adjbacklight.c
new file mode 100644
index 0000000..9fe68c1
--- /dev/null
+++ b/adjbacklight.c
@@ -0,0 +1,425 @@
+/* See LICENSE file for copyright and license details. */
+#include <sys/ioctl.h>
+#include <sys/wait.h>
+#include <alloca.h>
+#include <ctype.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+
+#include "arg.h"
+
+
+#ifndef BACKLIGHT_DIR
+# define BACKLIGHT_DIR "/sys/class/backlight"
+#endif
+
+
+
+char *argv0;
+static double brightness = 0;
+static int nbrightness = 0;
+static int cols = 80;
+static char *space;
+static char *line;
+
+
+
+static void
+usage(void)
+{
+ fprintf(stderr, "usage: %s [-g | -s [+|-]level[%%|%%%%]] [-a | device ...]\n", argv0);
+ exit(1);
+}
+
+
+static long int
+readfile(const char *path)
+{
+ int fd;
+ char buf[64];
+ ssize_t i, n;
+ long int value = 0;
+
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ return -1;
+
+ while ((n = read(fd, buf, sizeof(buf))) > 0) {
+ for (i = 0; i < n; i++) {
+ if (isdigit(buf[i]))
+ value = value * 10 + (buf[i] - '0');
+ else if (buf[i] != '\n')
+ goto out;
+ }
+ }
+
+out:
+ close(fd);
+ return n ? -1 : value;
+}
+
+
+static double
+getbrightness(const char *device, long int *out_cur, long int *out_max)
+{
+ size_t n = sizeof("//max_brightness") - 1;
+ char *path;
+ long int max, cur;
+
+ n += strlen(BACKLIGHT_DIR);
+ n += strlen(device);
+ path = alloca(n + 1);
+
+ if (sprintf(path, "%s/%s/max_brightness", BACKLIGHT_DIR, device) != (int)n)
+ abort();
+ max = readfile(path);
+ if (max < 1)
+ return -1;
+ if (out_max)
+ *out_max = max;
+
+ if (sprintf(path, "%s/%s/brightness", BACKLIGHT_DIR, device) != (int)n - 4)
+ abort();
+ cur = readfile(path);
+ if (cur < 0)
+ return -1;
+ if (out_cur)
+ *out_cur = cur;
+
+ return (double)cur / (double)max;
+}
+
+
+static int
+setbrightness(const char *device, long int value)
+{
+ size_t p = 0, n = sizeof("//brightness") - 1;
+ char *path, buf[128];
+ ssize_t r = 0;
+ int fd;
+
+ n += strlen(BACKLIGHT_DIR);
+ n += strlen(device);
+ path = alloca(n + 1);
+
+ if (sprintf(path, "%s/%s/brightness", BACKLIGHT_DIR, device) != (int)n)
+ abort();
+ if (sprintf(buf, "%li\n", value) < 0)
+ abort();
+
+ fd = open(path, O_WRONLY);
+ if (fd < 0)
+ return -1;
+
+ for (n = strlen(buf); p < n; p += (size_t)r)
+ if ((r = write(fd, &buf[p], n - p)) < 0)
+ break;
+
+ close(fd);
+ return r < 0 ? -1 : 0;
+}
+
+
+static int
+adjbrightness(const char *device, double pcur, long int cur, long int max, double adj, int inc, const char *suf)
+{
+ switch (strlen(suf)) {
+ case 2:
+ pcur = adj * pcur / 100 + pcur * inc;
+ cur = (long int)(pcur * (double)max + 0.5);
+ break;
+ case 1:
+ pcur = adj / 100 + pcur * inc;
+ cur = (long int)(pcur * (double)max + 0.5);
+ break;
+ case 0:
+ cur = (long int)adj + cur * inc;
+ break;
+ default:
+ abort();
+ }
+
+ cur = cur < 0 ? 0 : cur < max ? cur : max;
+ return setbrightness(device, cur);
+}
+
+
+static void
+bars(long int max, long int init, long int cur)
+{
+ long int mid = (long int)((double)cur * (double)(cols - 2) / (double)max + 0.5);
+
+ printf("\033[%iD\033[6A", cols);
+ printf("\033[2K┌%s┐\n", line);
+ space[mid] = '\0';
+ printf("\033[2K│\033[47m%s\033[49m%s│\n", space, &space[mid + 1]);
+ space[mid] = ' ';
+ printf("\033[2K└%s┘\n", line);
+ printf("\033[2KMaximum brightness: %li\n", max);
+ printf("\033[2KInitial brightness: %li\n", init);
+ printf("\033[2KCurrent brightness: %li\n", cur);
+
+ fflush(stdout);
+}
+
+
+static void
+interactive(const char *device, long int cur, long int max)
+{
+ long int step, init;
+ int c;
+
+ step = max / 200;
+ step = step ? step : 1;
+ init = cur;
+
+ printf("\n\n\n\n\n\n");
+ bars(max, init, cur);
+ while ((c = getchar()) != -1) {
+ switch (c) {
+ case 'q':
+ case '\n':
+ case 4:
+ printf("\n");
+ return;
+ case 'A':
+ case 'C':
+ cur += step << 1;
+ /* fall through */
+ case 'B':
+ case 'D':
+ cur -= step;
+ cur = cur < 0 ? 0 : cur < max ? cur : max;
+ adjbrightness(device, 0, 0, max, (double)cur, 0, "");
+ bars(max, init, cur);
+ }
+ }
+}
+
+
+static void
+handle_device(const char *device, int get, int set, double adj, int inc, const char *suf)
+{
+ double value;
+ long int cur, max;
+
+ value = getbrightness(device, &cur, &max);
+
+ if (get) {
+ if (value >= 0) {
+ brightness += value;
+ nbrightness++;
+ }
+ } else if (set) {
+ adjbrightness(device, value, cur, max, adj, inc, suf);
+ } else {
+ interactive(device, cur, max);
+ }
+}
+
+
+int
+main(int argc, char *argv[])
+{
+ int all = 0;
+ int get = 0;
+ char* set = NULL;
+ char set_prefix = '=';
+ double set_value = 0;
+ char* set_suffix = NULL;
+ struct winsize win;
+ struct termios saved_stty;
+ struct termios stty;
+ pid_t pid = -1;
+ DIR *dir;
+ struct dirent *ent;
+ int any = 0;
+
+ ARGBEGIN {
+ case 'a':
+ all = 1;
+ break;
+ case 'g':
+ get = 1;
+ break;
+ case 's':
+ set = EARGF(usage());
+ break;
+ default:
+ usage();
+ } ARGEND;
+
+ if ((get && set) || (argc && all))
+ usage();
+
+ /* Parse -s argument */
+ if (set) {
+ if (*set == '+' || *set == '-') {
+ set_prefix = *set;
+ set++;
+ }
+ if (!isdigit(*set) && *set != '.')
+ usage();
+ errno = 0;
+ set_value = strtod(set, &set_suffix);
+ if (errno || set_value < 0) {
+ fprintf(stderr, "%s: strtod %s: %s\n", argv0, set, strerror(errno));
+ return 1;
+ }
+ if (*set_suffix && strcmp(set_suffix, "%") && strcmp(set_suffix, "%%"))
+ usage();
+ if (set_prefix == '-') {
+ set_value = -set_value;
+ set_prefix = '+';
+ }
+ }
+
+ /* Check permissions (important because the program is installed with set-uid) */
+ if (getuid()) {
+ struct group *videogrp = getgrnam("video");
+ if (!videogrp && errno && errno != ENOENT && errno != ESRCH && errno != EPERM) {
+ /* Note, glibc sets errno to EIO if the group does not exist,
+ * this is the not the specified behavour by either POSIX or
+ * glibc, and it would be a security issue to treat it as OK.
+ * Additionally, EBADF is not treated as OK. */
+ fprintf(stderr, "%s: getgrnam video: %s\n", argv0, strerror(errno));
+ return 1;
+ } else if (videogrp) {
+ long ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
+ gid_t *groups;
+ int ngroups;
+ if (ngroups_max < 0 || ngroups_max > INT_MAX - 1) {
+ fprintf(stderr, "%s: sysconf _SC_NGROUPS_MAX: %s\n", argv0, strerror(errno));
+ return 1;
+ }
+ groups = alloca((size_t)ngroups_max * sizeof(*groups));
+ ngroups = getgroups((int)ngroups_max, groups);
+ if (ngroups < 0) {
+ fprintf(stderr, "%s: getgroups: %s\n", argv0, strerror(errno));
+ return 1;
+ }
+ while (ngroups--)
+ if (groups[ngroups] == videogrp->gr_gid)
+ break;
+ if (ngroups < 0) {
+ fprintf(stderr, "%s: only root and members of the group 'video' may run this command\n", argv0);
+ return 1;
+ }
+ }
+ }
+
+ if (!get && !set) {
+ int i;
+ printf("\n\n");
+ printf("If the program is abnormally aborted the may be some residual\n");
+ printf("effects on the terminal. the following commands should reset it:\n");
+ printf("\n");
+ printf(" stty sane\n");
+ printf(" printf '\\ec'\n");
+ printf("\n");
+ printf("\n\n\n\n");
+
+ /* Get the size of the terminal */
+ if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == -1)
+ fprintf(stderr, "%s: ioctl <stdout> TIOCGWINSZ: %s\n", argv0, strerror(errno));
+ else
+ cols = win.ws_col;
+
+ line = malloc((size_t)cols * 3);
+ space = malloc((size_t)cols);
+ if (!line || !space) {
+ fprintf(stderr, "%s: malloc: %s\n", argv0, strerror(ENOMEM));
+ return 1;
+ }
+ for (i = 0; i < cols; i++) {
+ line[i * 3 + 0] = (char)(0xE2);
+ line[i * 3 + 1] = (char)(0x94);
+ line[i * 3 + 2] = (char)(0x80);
+ }
+ memset(space, ' ', (size_t)cols);
+ space[cols - 1] = '\0';
+ line[(cols - 2) * 3] = '\0';
+
+ /* stty -icanon -echo */
+ if (tcgetattr(STDIN_FILENO, &stty)) {
+ fprintf(stderr, "%s: tcgetattr <stdin>: %s\n", argv0, strerror(errno));
+ return 1;
+ }
+ saved_stty = stty;
+ stty.c_lflag &= (tcflag_t)~(ICANON | ECHO);
+ if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &stty)) {
+ fprintf(stderr, "%s: tcsetattr <stdin>: %s\n", argv0, strerror(errno));
+ return 1;
+ }
+
+ /* Hide cursor */
+ printf("%s", "\033[?25l");
+ fflush(stdout);
+
+ /* Fork to diminish risk of unclean exit */
+ pid = fork();
+ if (pid == (pid_t)-1) {
+ fprintf(stderr, "%s: fork: %s\n", argv0, strerror(errno));
+ } else if (pid) {
+ waitpid(pid, NULL, 0);
+ goto done;
+ }
+ }
+
+ if (argc) {
+ for (; *argv; argv++) {
+ if (strchr(*argv, '/'))
+ *argv = strrchr(*argv, '/');
+ handle_device(*argv, get, !!set, set_value, set_prefix == '+', set_suffix);
+ }
+ } else {
+ if ((dir = opendir(BACKLIGHT_DIR))) {
+ while ((ent = readdir(dir))) {
+ if (all || strstr(ent->d_name, "acpi_video") == ent->d_name) {
+ if (*ent->d_name && *ent->d_name != '.') {
+ handle_device(ent->d_name, get, !!set, set_value, set_prefix == '+', set_suffix);
+ any = 1;
+ }
+ }
+ }
+ closedir(dir);
+ }
+ if (!any)
+ fprintf(stderr, "%s: cannot find any backlight devices\n", argv0);
+ }
+
+ if (get) {
+ if (nbrightness) {
+ brightness *= 100;
+ brightness /= (double)nbrightness;
+ printf("%.2lf%%\n", brightness);
+ fflush(stdout);
+ } else {
+ printf("%s\n", "100.00%");
+ fflush(stdout);
+ }
+ }
+
+done:
+ if (!get && !set && pid) {
+ /* Show cursor */
+ printf("%s", "\033[?25h");
+ fflush(stdout);
+
+ /* `stty icanon echo` */
+ if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &saved_stty)) {
+ fprintf(stderr, "%s: tcsetattr <stdin>: %s\n", argv0, strerror(errno));
+ return 1;
+ }
+ }
+
+ return 0;
+}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-09-19 21:48:19 +0000