up/down file: notice must be run as root

Signed-off-by: Jianhui Zhao <zhaojh329@gmail.com>

src/downfile.c

@@ -79,6 +79,11 @@ void download_file()
     static struct ev_signal sw;
     struct ev_io ior;
 
+    if (getuid() > 0) {
+        fprintf(stderr, "Operation not permitted, must be run as root\n");
+        return;
+    }
+
     if (!realpath(".", abspath))
         return;
 

src/upfile.c

@@ -73,6 +73,11 @@ void upload_file(const char *path)
     struct stat st;
     int fd;
 
+    if (getuid() > 0) {
+        fprintf(stderr, "Operation not permitted, must be run as root\n");
+        return;
+    }
+
     fd = open(path, O_RDONLY);
     if (fd < 0) {
         fprintf(stderr, "open '%s' failed: ", path);