Fix an inconsistency in socket option propagation on accept(). Propagate

the SS_NBIO flag from the parent socket to the child socket during an
accept() operation.

The file descriptor O_NONBLOCK flag would have been propagated already
by the fflag assignment, and therefore would have been inconsistent
with the underlying socket's so_state member.

This makes accept() more closely adhere to the API contract we effectively
outline in the manual page. Note also that Linux continues to differ here;
O_NONBLOCK is not propagated. The other BSDs do propagate the flag, as
does Solaris. The Single UNIX Specification does not offer specific
advice on this issue.

PR:		kern/45733
Requested by:	Jayanth Vijayaraghavan
Reviewed by:	rwatson

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c
index 30d2343..674e6fe 100644
--- a/sys/kern/uipc_syscalls.c
+++ b/sys/kern/uipc_syscalls.c
@@ -324,6 +324,7 @@ accept1(td, uap, compat)
 
 	TAILQ_REMOVE(&head->so_comp, so, so_list);
 	head->so_qlen--;
+	so->so_state |= (head->so_state & SS_NBIO);
 	so->so_qstate &= ~SQ_COMP;
 	so->so_head = NULL;