diff options
Diffstat (limited to 'home/.bin/bri.c')
-rwxr-xr-x | home/.bin/bri.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/home/.bin/bri.c b/home/.bin/bri.c new file mode 100755 index 00000000..d085814b --- /dev/null +++ b/home/.bin/bri.c @@ -0,0 +1,77 @@ +#if 0 +set -e +bin=$(dirname $0) +cc -Wall -Wextra -pedantic $@ -o $bin/bri $0 +sudo chown root:root $bin/bri +sudo chmod u+s $bin/bri +exit +#endif + +// Backlight brightness control. + +#include <dirent.h> +#include <err.h> +#include <errno.h> +#include <stdio.h> +#include <string.h> +#include <sysexits.h> +#include <unistd.h> + +static const char *CLASS = "/sys/class/backlight"; + +int main(int argc, char *argv[]) { + int error; + + if (argc < 2) errx(EX_USAGE, "usage: bri N | +... | -..."); + + error = chdir(CLASS); + if (error) err(EX_IOERR, "%s", CLASS); + + DIR *dir = opendir("."); + if (!dir) err(EX_IOERR, "%s", CLASS); + + struct dirent *entry; + while (NULL != (errno = 0, entry = readdir(dir))) { + if (entry->d_name[0] == '.') continue; + + error = chdir(entry->d_name); + if (error) err(EX_IOERR, "%s", entry->d_name); + break; + } + if (!entry) { + if (errno) err(EX_IOERR, "%s", CLASS); + errx(EX_CONFIG, "empty %s", CLASS); + } + + char *value = argv[1]; + + if (value[0] == '+' || value[0] == '-') { + FILE *actual = fopen("actual_brightness", "r"); + if (!actual) err(EX_IOERR, "actual_brightness"); + + unsigned int brightness; + int match = fscanf(actual, "%u", &brightness); + if (match == EOF) err(EX_IOERR, "actual_brightness"); + if (match < 1) err(EX_DATAERR, "actual_brightness"); + + size_t count = strnlen(value, 15); + if (value[0] == '+') { + brightness += 16 * count; + } else { + brightness -= 16 * count; + } + + char buf[15]; + snprintf(buf, sizeof(buf), "%u", brightness); + + value = buf; + } + + FILE *brightness = fopen("brightness", "w"); + if (!brightness) err(EX_IOERR, "brightness"); + + int count = fprintf(brightness, "%s", value); + if (count < 0) err(EX_IOERR, "brightness"); + + return EX_OK; +} |