[Libvir] [patch 9/9] Implement better error reporting

[Daniel P. Berrange]

On Mon, Feb 19, 2007 at 06:13:27PM +0000, Mark McLoughlin wrote:
> On Fri, 2007-02-16 at 19:28 +0000, Daniel P. Berrange wrote:
> > On Fri, Feb 16, 2007 at 02:44:57PM +0000, Mark McLoughlin wrote:
> 
> > > @@ -1226,6 +1332,7 @@ static int qemudDispatchPoll(struct qemu
> > >  
> > >      while (sock) {
> > >          struct qemud_socket *next = sock->next;
> > > +        /* FIXME: the daemon shouldn't exit on error here */
> > >          if (fds[fd].revents)
> > >              if (qemudDispatchServer(server, sock) < 0)
> > >                  return -1;
> > 
> > Yes & no. There are two reasons why qemuDispatchServer can fail. Either
> > it can fail to set  CLOSEXEC/NONBLOCK mode on the client socket, in
> > which case we could simply drop the client & continue without exiting.
> > If the accept() call fails for anything other than EAGAIN/EINTR then
> > we arguably should exit, because something serious has gone wrong.
> 
> 	Doesn't accept() fail if the client fails to send the final ACK? Do we
> want the daemon to die in that case? Think of an unprivileged user
> connecting to the system daemon's readonly socket ... you really want to
> be paranoid about the daemon exiting as it creates the opportunity for
> unprivileged users to take down guests and networks.

Yes, accept will fail if the client doesn't complete the handshake. I already
(tried) to take care of that case though by not returning an error code if the 
errno is EAGAIN

   if ((fd = accept(sock->fd, (struct sockaddr *)&addr, &addrlen)) < 0) {
        if (errno == EAGAIN)
            return 0;
        qemudLog(QEMUD_ERR, "Failed to accept connection: %s", strerror(errno));
        return -1;
    }

Looking at the man page, i think I also need to check for ECONNABORTED
errno value too.

Dan.
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