Re: [Qemu-devel] [PATCH v3 3/4] monitor: Prevent removing fd from set during init

[Eric Blake <eblake@redhat.com>]

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On 10/16/2012 12:08 PM, Corey Bryant wrote:
> If an fd is added to an fd set via the command line, and it is not
> referenced by another command line option (ie. -drive), then clean
> it up after QEMU initialization is complete.
> 
> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
> ---
> v3:
>   - This patch was split into it's own patch in v3
>     (eblake@redhat.com, kwolf@redhat.com)
> 
>  monitor.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

> 
> diff --git a/monitor.c b/monitor.c
> index 5d5de41..0dae7ac 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -2105,8 +2105,9 @@ static void monitor_fdset_cleanup(MonFdset *mon_fdset)
>      MonFdsetFd *mon_fdset_fd_next;
>  
>      QLIST_FOREACH_SAFE(mon_fdset_fd, &mon_fdset->fds, next, mon_fdset_fd_next) {
> -        if (mon_fdset_fd->removed ||
> -                (QLIST_EMPTY(&mon_fdset->dup_fds) && mon_refcount == 0)) {
> +        if ((mon_fdset_fd->removed ||
> +                (QLIST_EMPTY(&mon_fdset->dup_fds) && mon_refcount == 0)) &&
> +                runstate_is_running()) {

This condition looks sufficient for command line parsing; however, I
have to wonder if there are any long-term ill effects, such as if I
pause a guest, then close an fdset, where qemu keeps the fd open until I
continue the guest.  But thinking a bit more, we never promised that
qemu would close fds right away, but only that it wouldn't leak fds by
closing them whenever qemu thinks it is convenient.

>              close(mon_fdset_fd->fd);
>              g_free(mon_fdset_fd->opaque);
>              QLIST_REMOVE(mon_fdset_fd, next);
> 

-- 
Eric Blake   eblake@redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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