On Thu, May 24, 2018 at 01:16:24PM -0500, Eric Blake wrote: > On 05/24/2018 11:01 AM, Michael S. Tsirkin wrote: > > On Thu, May 24, 2018 at 11:00:19AM -0500, Eric Blake wrote: > > > On 05/24/2018 10:52 AM, Eric Blake wrote: > > > > > > > Also, since waitpid() can only return either s->qemu_pid or -1 as we > > > > aren't using WNOHANG, it may also be worth asserting that if pid == -1, > > > > we either have EAGAIN (but why aren't we looping in that case?) or > > > > ECHILD. > > > > > > I meant EINTR, not EAGAIN. But in general, using waitpid() to collect > > > process status without doing it in a loop is risky. > > > > Interesting. Risky how? > > If your process has any signal handler installed, then an EINTR failure > means you interpret a transient failure to grab process status (because your > check was interrupted by something else) as a permanent failure, unless you > go back to another waitpid() in a loop.
I don't think we have a handler installed, though. > -- > Eric Blake, Principal Software Engineer > Red Hat, Inc. +1-919-301-3266 > Virtualization: qemu.org | libvirt.org