From 6ded785a192f3fd5dc0b402f26eb7d8aab001846 Mon Sep 17 00:00:00 2001
From: Hans Rosenfeld <hans.rosenfeld@joyent.com>
Date: Tue, 17 Sep 2019 10:15:24 +0200
Subject: [PATCH] OS-7991 port_get() and port_getn() implementation disagrees
 with documentation

---
 usr/src/head/port.h                    | 10 ++++++----
 usr/src/lib/libc/port/gen/event_port.c |  7 +++++--
 usr/src/uts/common/fs/portfs/port.c    | 16 +++++++++++++++-
 3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/usr/src/head/port.h b/usr/src/head/port.h
index 8b09b39c8b3e..66ced20d37dd 100644
--- a/usr/src/head/port.h
+++ b/usr/src/head/port.h
@@ -23,12 +23,13 @@
  * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
+/*
+ * Copyright 2019 Joyent, Inc.
+ */
 
 #ifndef	_PORT_H
 #define	_PORT_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/types.h>
 #include <sys/port.h>
 
@@ -45,8 +46,9 @@ int	port_associate(int, int, uintptr_t, int, void *);
 int	port_dissociate(int, int, uintptr_t);
 int	port_send(int, int, void *);
 int	port_sendn(int [], int [], uint_t, int, void *);
-int	port_get(int, port_event_t *, struct timespec *);
-int	port_getn(int, port_event_t [], uint_t, uint_t *, struct timespec *);
+int	port_get(int, port_event_t *, const struct timespec *);
+int	port_getn(int, port_event_t [], uint_t, uint_t *,
+    const struct timespec *);
 int	port_alert(int, int, int, void *);
 
 #ifdef	__cplusplus
diff --git a/usr/src/lib/libc/port/gen/event_port.c b/usr/src/lib/libc/port/gen/event_port.c
index df8f5c7a6419..58cc8334e44c 100644
--- a/usr/src/lib/libc/port/gen/event_port.c
+++ b/usr/src/lib/libc/port/gen/event_port.c
@@ -23,6 +23,9 @@
  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
+/*
+ * Copyright 2019 Joyent, Inc.
+ */
 
 #include "lint.h"
 #include <sys/types.h>
@@ -64,7 +67,7 @@ port_associate(int port, int source, uintptr_t object, int events, void *user)
 
 
 int
-port_get(int port, port_event_t *pe, struct timespec *to)
+port_get(int port, port_event_t *pe, const struct timespec *to)
 {
 	rval_t	r;
 	if (to)
@@ -77,7 +80,7 @@ port_get(int port, port_event_t *pe, struct timespec *to)
 
 int
 port_getn(int port, port_event_t list[], uint_t max, uint_t *nget,
-    struct timespec *timeout)
+    const struct timespec *timeout)
 {
 	rval_t	r;
 	if (nget == NULL) {
diff --git a/usr/src/uts/common/fs/portfs/port.c b/usr/src/uts/common/fs/portfs/port.c
index 04a2a421dbf4..384d54276dbd 100644
--- a/usr/src/uts/common/fs/portfs/port.c
+++ b/usr/src/uts/common/fs/portfs/port.c
@@ -25,7 +25,7 @@
  */
 
 /*
- * Copyright (c) 2015 Joyent, Inc.  All rights reserved.
+ * Copyright 2019 Joyent, Inc.
  */
 
 #include <sys/types.h>
@@ -615,6 +615,20 @@ portfs(int opcode, uintptr_t a0, uintptr_t a1, uintptr_t a2, uintptr_t a3,
 			error = port_getn(pp, (port_event_t *)a1, 1,
 			    (uint_t *)&nget, &port_timer);
 		} while (nget == 0 && error == 0 && port_timer.pgt_loop);
+
+		/*
+		 * There are cases when a timeout is given to port_getn() where
+		 * it returns no events but also no error, such as when events
+		 * are available but can't be copied out, or when there are no
+		 * events and the timeout is all zero.
+		 *
+		 * This isn't a problem in PORT_GETN as the number of retrieved
+		 * events is always returned correctly, but in the case of
+		 * PORT_GET we need to fix this up here and return ETIME as
+		 * documented.
+		 */
+		if (nget == 0 && error == 0 && a4 != 0)
+			error = ETIME;
 		break;
 	}
 	case	PORT_GETN: