util: report write errors in sysfs_write

src/util.cpp

@@ -59,11 +59,19 @@ void sysfs_write(char *path, char *content)
 {
 	std::cout << "Write: " << content << " -> " << path << std::endl;
 	int fd;
-	fd = open(path, O_WRONLY);
-	write(fd, content, strlen(content));
+	if (fd = open(path, O_WRONLY) == -1)
+	{
+		perror("Failed to open sysfs file");
+		return;
+	}
+	if (write(fd, content, strlen(content) == -1))
+	{
+		perror("Failed to write sysfs file");
+	}
 	close(fd);
 }
 
+
 char *getprop(char *key)
 {
 	std::array<char, 128> buffer;