[libvirt] [PATCH 2/4] qemu: monitor: Add infrastructure to access VM logs for better err msgs

[Peter Krempa]

On 09/24/13 14:19, Ján Tomko wrote:
> On 09/19/2013 11:23 AM, Peter Krempa wrote:
>> Early VM startup errors usually produce a better error message in the
>> machine log file. Currently we were accessing it only when the process
>> exited during certain phases of startup. This will help adding a more
>> comprehensive error extraction for early qemu startup phases.
>>
>> This patch adds infrastructure to keep a file descriptor for the machine
>> log file that will be used in case an error happens.
>> ---
>>
> 
> Is there any reason why we need to duplicate the file descriptor instead of
> opening the log again in qemuMonitorIO when it hangs up?

I wanted to avoid having to open it again as it's open only during
startup of the VM. Also, I didn't like the idea of opening a file in the
event loop.

> 
> You wouldn't have to worry about the position in 4/4 and add this variable to
> the monitor that's only valid at the start.

Actually I had a brain lapse while writing the code and the seek
actually isn't necessary as reading from a FD doesn't influence reads
from the duplicated one.

> 
> Jan
> 

Peter

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