Messages in this thread Patch in this message | | | Date | Mon, 25 Jan 2021 15:36:50 -0800 | From | Jakub Kicinski <> | Subject | Re: [PATCH] af_unix: Allow Unix sockets to raise SIGURG |
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On Fri, 22 Jan 2021 15:06:37 +0000 Matthew Wilcox (Oracle) wrote: > From: Rao Shoaib <rao.shoaib@oracle.com> > > TCP sockets allow SIGURG to be sent to the process holding the other > end of the socket. Extend Unix sockets to have the same ability. > > The API is the same in that the sender uses sendmsg() with MSG_OOB to > raise SIGURG. Unix sockets behave in the same way as TCP sockets with > SO_OOBINLINE set.
Noob question, if we only want to support the inline mode, why don't we require SO_OOBINLINE to have been called on @other? Wouldn't that provide more consistent behavior across address families?
With the current implementation the receiver will also not see MSG_OOB set in msg->msg_flags, right?
> SIGURG is ignored by default, so applications which do not know about this > feature will be unaffected. In addition to installing a SIGURG handler, > the receiving application must call F_SETOWN or F_SETOWN_EX to indicate > which process or thread should receive the signal. > > Signed-off-by: Rao Shoaib <rao.shoaib@oracle.com> > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> > --- > net/unix/af_unix.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c > index 41c3303c3357..849dff688c2c 100644 > --- a/net/unix/af_unix.c > +++ b/net/unix/af_unix.c > @@ -1837,8 +1837,6 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, > return err; > > err = -EOPNOTSUPP; > - if (msg->msg_flags&MSG_OOB) > - goto out_err; > > if (msg->msg_namelen) { > err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; > @@ -1903,6 +1901,9 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, > sent += size; > } > > + if (msg->msg_flags & MSG_OOB) > + sk_send_sigurg(other); > + > scm_destroy(&scm); > > return sent;
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