shutdown gotcha with Win32 host

Matt Swift swift "at" alum.mit.edu
Tue, 05 Mar 2002 22:47:10 +0000


When running VNC as a service on Win2k, one can reboot the host
machine via the remote client.  The machine reboots, the service runs,
and one can reconnect with the client, log in, and so on --

*unless* during the shutdown process Windows encounters a program that
it cannot close (most notably, any Cygwin bash shell).  Windows then
puts up a popup window asking the user to confirm a more forceful kill
of that program.  The sequence of events in this case is the
following:

    select reboot on host
    VNC host closes client connection
    Windows encounters a problem process and requests user input

In this state, the VNC host responds to attempts to reconnect with a
client, but after authentication immediately drops them, with a
message to the effect that the connection was dropped because a
shutdown is in process.

The result is the inconvenient necessity, when rebooting a host
remotely, to kill as many processes as possible manually, to avoid the
possibility of locking oneself out of the system permanently, until
one can visit the actual remote machine and manually confirm to
Windows that it may kill that dratted Cygwin shell (or other process).

There is more than one way to address this problem -- and probably
more than one way ought to be pursued.

Is there a way to invoke an "unconditional reboot" in Win2k that I do
not know about?

There will always be a risk of a "stuck" process, so if there is not a
way to ask Windows to reboot unconditionally, then I think VNC ought
to let clients connect when a shutdown is in process.  I do not
understand the reason it declines to accept connections, but whatever
it is, I would be surprised if it applies in the circumstances
described, and would be surprised if the negative consequences of
allowing a connection are as dire as the consequences of declining
one.

Any insight or suggestions will be greatly appreciated.
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