Authorization in XfceConsolekit and XfceSystemd
systemd-logind can return challenge for CanSuspend() et al. if systemd is compiled with polkit support, which is generally the case.
https://www.freedesktop.org/software/systemd/man/org.freedesktop.login1.html
CanPowerOff(), CanReboot(), CanHalt(), CanSuspend(), CanHibernate(), CanHybridSleep(), CanSuspendThenHibernate(), CanRebootParameter(), CanRebootToFirmwareSetup(), CanRebootToBootLoaderMenu(), and CanRebootToBootLoaderEntry() test whether the system supports the respective operation and whether the calling user is allowed to execute it. Returns one of "na", "yes", "no", and "challenge". If "na" is returned, the operation is not available because hardware, kernel, or drivers do not support it. If "yes" is returned, the operation is supported and the user may execute the operation without further authentication. If "no" is returned, the operation is available but the user is not allowed to execute the operation. If "challenge" is returned, the operation is available but only after authorization.
XfceSystemd only checks for yes:
XfceConsolekit on the other hand has challenge check for CanSuspend(), CanHibernate() and CanHybridSleep():
Could this be generalized in xfce_consolekit_can_method() for all methods?