Re: [libvirt] [PATCH 5/5] read saved vm status on libvirtd startup
On Mon, Jan 12, 2009 at 11:30:19AM +0000, Daniel P. Berrange wrote:
There's different needs for each file descriptor
- stdin_fd - this is only ever used for incoming migration data
all other times it is hooked up to /dev/null. So we don't need
to keep this FD around at all
Agreed.
- stdout_fd - AFAIK, the only time we get any data on stdout is
when we run qemu -help to check support args. Current code will
read & log all data on stdout, but I believe this is effectively
nothing and so we could just hook it to /dev/null & ignore it
We can just
dup that one too while at it in case qemu/kvm should dump
anything else there.
- stderr_fd - libvirtd reads this FD & logs the data to the
domain
logfile in /var/log/libvirt/qemu/$NAME.log. Instead of having
the daemon process this logging, we can just dup() the file straight
onto the logfile FD, so data will be logged even when libvirtd is
not running. The only minor complication is that we need to parse
the logfile to get the monitor TTY path.
There's one more thing (which was
my intial reason for asking): we also use
this fd in qemudDispatchVMEvent() to detect vm shutdown:
if (events & VIR_EVENT_HANDLE_READABLE) {
if (qemudVMData(driver, vm, fd) < 0)
failed = 1;
} else {
quit = 1;
}
}
if (failed || quit) {
event = virDomainEventNewFromObj(vm,
VIR_DOMAIN_EVENT_STOPPED,
quit ?
VIR_DOMAIN_EVENT_STOPPED_SHUTDOWN
:
VIR_DOMAIN_EVENT_STOPPED_FAILED);
qemudShutdownVMDaemon(NULL, driver, vm);
if (!vm->persistent) {
virDomainRemoveInactive(&driver->domains,
vm);
vm = NULL;
}
Using the monitor fd for this instead should work. Would that be o.k.?
-- Guido