qemu-storage-daemon: add --pidfile option
Daemons often have a --pidfile option where the pid is written to a file
so that scripts can stop the daemon by sending a signal.
The pid file also acts as a lock to prevent multiple instances of the
daemon from launching for a given pid file.
QEMU, qemu-nbd, qemu-ga, virtiofsd, and qemu-pr-helper all support the
--pidfile option. Add it to qemu-storage-daemon too.
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <
20210302142746.170535-1-stefanha@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>