add some simple error checking at startup

esgd.py

@@ -193,10 +193,15 @@ location = "/tmp/test"
 if __name__ == "__main__":
     switchgrp = grp.getgrnam("nobody").gr_gid
     switchusr = pwd.getpwnam("nobody").pw_uid
-    with socketserver.TCPServer((host, port), GopherHandler) as server:
-        os.setgid(switchgrp)
-        os.seteuid(switchusr)
-        log.log("switch user successful")
-        os.chdir(location)
-        log.log("change directory successful")
-        server.serve_forever()
+    try:
+        with socketserver.TCPServer((host, port), GopherHandler) as server:
+            os.setgid(switchgrp)
+            os.seteuid(switchusr)
+            log.log("switch user successful")
+            os.chdir(location)
+            log.log("change directory successful")
+            server.serve_forever()
+    except PermissionError:
+        log.error("invalid permissions")
+    except OSError:
+        log.error("address already in use")