python program running as root to open urls via normal user

I have a python program that runs as root one if its functions at the click of a button is to open a webpage. It kept opening the webpage in firefox as root so I try to use setuid with no avail. Here's what I've tried to get to open the link as a normal user:

from PyQt4 import QtGui, QtCore
import pwd
import os
import webbrowser


def username():
    euid = os.geteuid()
    print euid
    if 'PKEXEC_UID' in os.environ:
        user = pwd.getpwuid(int(os.environ["PKEXEC_UID"])).pw_name
        print user
        return user
    elif euid == 0 and 'PKEXEC_UID' not in os.environ:
        user = os.environ["SUDO_USER"]
        print user
        return user

def openLinks():
    uidChange = pwd.getpwnam(username()).pw_uid
    pidx = os.fork()
    if pidx == 0:
        try:
            os.setuid(uidChange)
            QtGui.QDesktopServices.openUrl(QtCore.QUrl("http://stackoverflow.com"))
            #webbrowser.open("http://stackoverflow.com")

        finally:
            os._exit(0)
    os.waitpid(pidx, 0)

openLinks()