diff options
Diffstat (limited to 'bin/bri.c')
-rw-r--r-- | bin/bri.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/bin/bri.c b/bin/bri.c new file mode 100644 index 00000000..413958c5 --- /dev/null +++ b/bin/bri.c @@ -0,0 +1,83 @@ +/* Copyright (c) 2017, June McEnroe <programble@gmail.com> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <dirent.h> +#include <err.h> +#include <errno.h> +#include <stdio.h> +#include <stdlib.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; + + const char *input = (argc > 1) ? argv[1] : NULL; + + error = chdir(CLASS); + if (error) err(EX_OSFILE, "%s", CLASS); + + DIR *dir = opendir("."); + if (!dir) err(EX_OSFILE, "%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_OSFILE, "%s/%s", CLASS, entry->d_name); + break; + } + if (!entry) { + if (errno) err(EX_IOERR, "%s", CLASS); + errx(EX_CONFIG, "%s: empty", CLASS); + } + + FILE *actual = fopen("actual_brightness", "r"); + if (!actual) err(EX_OSFILE, "%s/actual_brightness", CLASS); + + unsigned value; + int match = fscanf(actual, "%u", &value); + if (match == EOF) err(EX_IOERR, "%s/actual_brightness", CLASS); + if (match < 1) errx(EX_DATAERR, "%s/actual_brightness", CLASS); + + if (!input) { + printf("%u\n", value); + return EX_OK; + } + + if (input[0] == '+' || input[0] == '-') { + size_t count = strnlen(input, 16); + if (input[0] == '+') { + value += 16 * count; + } else { + value -= 16 * count; + } + } else { + value = strtoul(input, NULL, 0); + } + + FILE *brightness = fopen("brightness", "w"); + if (!brightness) err(EX_OSFILE, "%s/brightness", CLASS); + + int size = fprintf(brightness, "%u", value); + if (size < 0) err(EX_IOERR, "brightness"); + + return EX_OK; +} |