tree a4d062e324c9eaa8a6d9432af65d1c5e40dd05ff
parent 1a751ebfbb2d7a696b889d8208cb5ffc83c090b1
author Stefan Hajnoczi <stefanha@redhat.com> 1364375446 +0100
committer Luiz Capitulino <lcapitulino@redhat.com> 1364917657 -0400

chardev: clear O_NONBLOCK on SCM_RIGHTS file descriptors

When we receive a file descriptor over a UNIX domain socket the
O_NONBLOCK flag is preserved.  Clear the O_NONBLOCK flag and rely on
QEMU file descriptor users like migration, SPICE, VNC, block layer, and
others to set non-blocking only when necessary.

This change ensures we don't accidentally expose O_NONBLOCK in the QMP
API.  QMP clients should not need to get the non-blocking state
"correct".

A recent real-world example was when libvirt passed a non-blocking TCP
socket for migration where we expected a blocking socket.  The source
QEMU produced a corrupted migration stream since its code did not cope
with non-blocking sockets.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>