From: Stefan Hajnoczi Date: Thu, 4 Apr 2013 14:18:31 +0000 (+0200) Subject: chardev: clear O_NONBLOCK on SCM_RIGHTS file descriptors X-Git-Tag: v1.4.1~17 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=27c71355fbf7f999f3fbb8ec42ec88210211b6f4;p=thirdparty%2Fqemu.git 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 (cherry picked from commit e374f7f816171f9783c1d9d00a041f26379f1ac6) Signed-off-by: Stefan Hajnoczi Signed-off-by: Michael Roth --- diff --git a/qemu-char.c b/qemu-char.c index 050764b270e..f4a74ac26ed 100644 --- a/qemu-char.c +++ b/qemu-char.c @@ -2252,6 +2252,9 @@ static void unix_process_msgfd(CharDriverState *chr, struct msghdr *msg) if (fd < 0) continue; + /* O_NONBLOCK is preserved across SCM_RIGHTS so reset it */ + qemu_set_block(fd); + #ifndef MSG_CMSG_CLOEXEC qemu_set_cloexec(fd); #endif