get_session_info

    {
        name => STR,            # user name
        realname => STR,        # user name - descriptive label
        role => STR,            # role
        role_label => STR,      # role - descriptive label
        pki_realm => STR,       # PKI realm
        pki_realm_label => STR, # PKI realm - descriptive label
        checksum => STR,        # config checksum
        sid => STR,             # session ID
        userinfo => {           # additional user info, depending on authentication backend
            realname => STR,    # optional
            email => STR,       # optional
            ...
        },
        authinfo => {           # optional, params for authentication handlers
            logout => STR,      # redirect target for logout (used by UI)
            ....
        }
    }