diff --git a/brightnessctl.c b/brightnessctl.c
index 1917212..4493552 100644
--- a/brightnessctl.c
+++ b/brightnessctl.c
@@ -60,8 +60,8 @@ static unsigned long percent_to_val(float, struct device *);
 static bool find_devices(struct device **, char *);
 static bool save_device_data(struct device *);
 static bool restore_device_data(struct device *);
-static bool ensure_dir(char *);
-static bool ensure_dev_dir(struct device *);
+static bool mkdir_parent(const char *);
+static bool ensure_dir(const char *);
 
 #ifdef ENABLE_LOGIND
 static bool logind_set_brightness(struct device *);
@@ -266,9 +266,16 @@ int process_device(struct device *dev) {
 		}
 		free(file_path);
 	}
+	mode_t old = umask(0);
+	char *sys_run_dir = getenv("XDG_RUNTIME_DIR");
+	if (sys_run_dir) {
+		umask(0077);
+		run_dir = dir_child(sys_run_dir, "brightnessctl");
+	}
 	if (p.save)
 		if (!save_device_data(dev))
 			fprintf(stderr, "Could not save data for device '%s'.\n", dev->id);
+	umask(old);
 	if (p.restore) {
 		if (restore_device_data(dev))
 			p.operation = RESTORE;
@@ -557,104 +564,79 @@ int read_devices(struct device **devs) {
 }
 
 bool save_device_data(struct device *dev) {
-	char c[16];
-	size_t s = sprintf(c, "%u", dev->curr_brightness);
-	char *d_path = cat_with('/', run_dir, dev->class, dev->id);
-	FILE *fp;
-	mode_t old = 0;
-	int error = 0;
-	errno = 0;
-	if (s <= 0) {
-		fprintf(stderr, "Error converting device data.");
-		error++;
-		goto fail;
-	}
-	if (!ensure_dev_dir(dev))
-		goto fail;
-	old = umask(0);
-	fp = fopen(d_path, "w");
-	umask(old);
-	if (!fp)
-		goto fail;
-	if (fwrite(c, 1, s, fp) < s) {
-		fprintf(stderr, "Error writing to '%s'.\n", d_path);
-		error++;
+	char *c_path = dir_child(run_dir, dev->class);
+	char *d_path = dir_child(c_path, dev->id);
+	bool ret = true;
+	if (ensure_dir(c_path)) {
+		FILE *fp = fopen(d_path, "wb");
+		if (fp) {
+			fwrite(&dev->curr_brightness, sizeof(dev->curr_brightness), 1, fp);
+			if (ferror(fp)) {
+				ret = false;
+				fprintf(stderr, "Error writing to '%s'.\n", d_path);
+			}
+			fclose(fp);
+		} else {
+			ret = false;
+			fprintf(stderr, "Error opening '%s': %s\n", d_path, strerror(errno));
+		}
+	} else {
+		fprintf(stderr, "Failed to access or create '%s': %s\n", path, strerror(errno));
 	}
-	fclose(fp);
-fail:
+	free(c_path);
 	free(d_path);
-	if (errno) {
-		perror("Error saving device data");
-		error++;
-	}
-	return !error;
+	return ret;
 }
 
 bool restore_device_data(struct device *dev) {
-	char buf[16];
 	char *filename = cat_with('/', run_dir, dev->class, dev->id);
-	char *end;
-	FILE *fp;
-	memset(buf, 0, 16);
-	errno = 0;
-	if (!(fp = fopen(filename, "r")))
-		goto fail;
-	if (!fread(buf, 1, 15, fp))
-		goto rfail;
-	dev->curr_brightness = strtol(buf, &end, 10);
-	if (end == buf)
-		errno = EINVAL;
-rfail:
-	fclose(fp);
-fail:
-	free(filename);
-	if (errno) {
+	bool ret = true;
+	FILE *fp = fopen(filename, "rb");
+	if (fp) {
+		unsigned int val;
+		fread(&val, sizeof(val), 1, fp);
+		if (!ferror(fp)) {
+			dev->curr_brightness = val;
+		} else {
+			ret = false;
+			fprintf(stderr, "Error reading file '%s'\n", filename);
+		}
+		fclose(fp);
+	} else {
+		ret = false;
 		perror("Error restoring device data");
-		return false;
 	}
-	return true;
+	free(filename);
+	return ret;
 }
 
-
-bool ensure_dir(char *dir) {
-	struct stat sb;
-	if (stat(dir, &sb)) {
-		if (errno != ENOENT)
-			return false;
-		errno = 0;
-		if (mkdir(dir, 0777)) {
-			return false;
-		}
-		if (stat(dir, &sb))
-			return false;
-	}
-	if (!S_ISDIR(sb.st_mode)) {
-		errno = ENOTDIR;
+bool mkdir_parent(const char *path) {
+	if (!path)
 		return false;
+	bool ret = true;
+	size_t size = strlen(path) + 1;
+	char *tmp = calloc(1, size);
+	if (!tmp)
+		return false;
+	for (const char *p = path; (p - path) < (long)size; p++) {
+		if ((*p == '/' || *p == '\0') && (p != path && *(p - 1) != '/')) {
+			memcpy(tmp, path, p - path);
+			tmp[p - path] = 0;
+			if (mkdir(tmp, 0777) && errno != EEXIST) {
+				ret = false;
+				perror(tmp);
+				break;
+			}
+		}
 	}
-	return true;
-}
-
-static bool ensure_run_dir() {
-	static bool set;
-	if (!set) {
-		char *sys_run_dir = getenv("XDG_RUNTIME_DIR");
-		if (sys_run_dir)
-			run_dir = dir_child(sys_run_dir, "brightnessctl");
-		set = true;
-	}
-	return ensure_dir(run_dir);
+	free(tmp);
+	return ret;
 }
 
-bool ensure_dev_dir(struct device *dev) {
-	char *cpath;
-	bool ret;
-	if (!ensure_run_dir())
-		return false;
-	cpath = dir_child(run_dir, dev->class);
-	ret = ensure_dir(cpath);
-	free(cpath);
-	return ret;
+static bool ensure_dir(const char * path) {
+	if (!access(path, W_OK))
+		return true;
+	return errno == ENOENT ? mkdir_parent(path) : false;
 }
 
 char *_cat_with(char c, ...) {