diff --git a/src/service/libc.cr b/src/service/libc.cr
index 1accad3..46b61ae 100644
--- a/src/service/libc.cr
+++ b/src/service/libc.cr
@@ -25,14 +25,11 @@ module System
 
 		passwd = pointer.value
 
-		# FIXME: Probably should get some errno magic right now.
-		if 0 != LibC.setuid passwd.pw_uid
-			raise Exception.new "setuid failed"
-		end
+		r = LibC.setgid passwd.pw_gid
+		raise Errno.new "setgid" if r != 0
 
-		if 0 != LibC.setgid passwd.pw_gid
-			raise Exception.new "setuid failed"
-		end
+		r = LibC.setuid passwd.pw_uid
+		raise Errno.new "setuid" if r != 0
 
 		passwd
 	end