persona.py 文件源码

def become_user(name):
    '''
    Change the current process' effective UID to that of the given user name.
    Can only be called by super user 0. This function is only intended for use
    from the ``init`` process during system boot.

    :arg name: An OS user name. Must be found in the ``password`` database, or
        a replacement authentication system.
    :returns: The user's home directory.
    '''
    uid = ave.pwd.getpwnam_uid(name)
    gid = ave.pwd.getpwnam_gid(name)

    if os.geteuid() == uid:
        return

    if os.geteuid() != 0:
        raise Exception('only root can execute with modified privileges')
    try:
        os.setgid(gid) # must be done before changing euid
        os.setuid(uid)
    except OSError, e:
        if e.errno == errno.EPERM:
            raise Exception(
                'could not execute with modified privileges: %s' % str(e)
            )
    return ave.pwd.getpwnam_dir(name)