1 files changed, 85 insertions, 0 deletions
diff --git a/bin/bri.c b/bin/bri.c
new file mode 100644
index 00000000..c9bf6b0c
--- /dev/null
+++ b/bin/bri.c
@@ -0,0 +1,85 @@
+/* Copyright (C) 2017  June McEnroe <june@causal.agency>
+ *
+ * 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>
+
+typedef unsigned uint;
+
+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, "actual_brightness");
+
+	uint value;
+	int match = fscanf(actual, "%u", &value);
+	if (match == EOF) err(EX_IOERR, "actual_brightness");
+	if (match < 1) errx(EX_DATAERR, "actual_brightness");
+
+	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, "brightness");
+
+	int size = fprintf(brightness, "%u", value);
+	if (size < 0) err(EX_IOERR, "brightness");
+
+	return EX_OK;
+}