On Tue, Apr 08, 2008 at 04:45:23AM -0400, Daniel Veillard wrote:
> Then what happen if you pass a wrong string ? Is there any way to get a
> meaningful error back from qemu and report it. Thet would IMHO be quite
> better than tracking the evolution of the emulation in QEmu, plus the
> added benefit of not being tied to a strict version of QEmu,
The error handling in this part of the code seems a bit confused at
the moment. For example:
if (virExecNonBlock(conn, argv, &vm->pid,
vm->stdin, &vm->stdout, &vm->stderr) == 0) {
/* [add new qemu to list of VMs] */
}
/* [free up various resources] */
if (virEventAddHandle(vm->stdout,
POLLIN | POLLERR | POLLHUP,
qemudDispatchVMEvent,
driver) < 0) {
qemudShutdownVMDaemon(conn, driver, vm);
return -1;
}
/* [another call to virEventAddHandle] */
if (qemudWaitForMonitor(conn, driver, vm) < 0) {
qemudShutdownVMDaemon(conn, driver, vm);
return -1;
}
return 0;
If virExecNonBlock fails, because one of the system calls such as
fork(2) or pipe(2) fails, then vm->stdout may be uninitialized. I
think it will assume the value 0 in this case and virEventAddHandle
will quite happily register a handler for fd 0.
On the other hand it is tricky to know what to do when launching a
process. In the case where KVM doesn't understand part of the command
line arguments, the fork & exec will both succeed and the earliest
point where we will see any error will be at qemudWaitForMonitor
(because the monitor won't come up -- note this code is synchronous).
Rich.
--
Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones
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