[libvirt] PATCH Fix QEMU monitor prompt confusion

[Daniel Veillard]

On Tue, Jul 07, 2009 at 05:43:34PM +0100, Daniel P. Berrange wrote:
> When you first connect to the QEMU monitor after a VM starts, it will
> print out 
> 
>   QEMU 0.10.5 monitor - type 'help' for more information
> 
> We already have code to detect & discard this. Unfortunately it seems that
> with QEMU >= 0.10.0 it will also print out this prompt when you disconnect
> and reconnect to the QEMU monitor. Except it doesn't print this out every
> time. It only appears to happen 50% of the time when libvirtd restarts
> and reconnects. When it does happen though it totally breaks all future
> monitor commands libvirt tries to run.
> 
> This patch takes a fairly simple approach to solving it. Before running
> any QEMU monitor command, read and discard all pending data. 99% of the
> time there will be none, but if there is, this saves us from disaster.

  Okay, but shouldn't that routine look for the data read too,
maybe we would need to raise events on some conditions reported
by QEmu between commands. At least it's a clearly separated function
so easy to modify. ACK

Daniel

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