Re: [Qemu-devel] [PATCH] vl.c: do not allow --daemonize in combination with --preconfig CLI option

[Michal Privoznik <mprivozn@redhat.com>]

On 06/20/2018 03:24 PM, Igor Mammedov wrote:
> some users when using --daemonize expect that QEMU will parse CLI options,
> initialize VM and only then complete daemonzation by signalling lead
> process to exit and start listening on monitor socket. So users treat
> parent process exit as sync point to connect to QEMU's monitor.
> 
> That however doesn't work when --preconfig options is used, since it
> provides monitor before completing daemonization and expects user to
> issue exit-preconfig command when additional configuration via monitor
> is finished. We also can't move completing daemonization before
> preconfig monitor becomes available, since that would imply:
>   * partially loosing ability to configure QEMU instance in --preconfig
>     mode since QEMU might drop privileges, chroot and do other things
>     when daemonization is completed
>   * lead to loss of error messages in case they would happen after
>     daemonization
> 
> Be proactive now and make options mutually exclusive, so users would
> get clear error message instead of waiting for lead process exit
> indefinitely before connecting to monitor.
> 
> PS:
> In case someone would come up with usecase where both options should
> be enabled at the same time we could drop this restriction as far
> as daemonization point is left where it is now (os_setup_post).
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
>  vl.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 

ACK

Michal