[src/trunk]: src/sys/dev/audio audio(4): Set AUMODE_PLAY/RECORD only if asked...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/96611e6fc109
branches:  trunk
changeset: 379463:96611e6fc109
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Tue Jun 01 21:12:24 2021 +0000

description:
audio(4): Set AUMODE_PLAY/RECORD only if asked _and_ supported.

If one is requested and _not_ supported, fail; otherwise we might
enter audio_write with a null play track and crash on KASSERT.

diffstat:

 sys/dev/audio/audio.c |  18 ++++++++++++++----
 1 files changed, 14 insertions(+), 4 deletions(-)

diffs (41 lines):

diff -r 3a19cf2065c2 -r 96611e6fc109 sys/dev/audio/audio.c
--- a/sys/dev/audio/audio.c     Tue Jun 01 21:11:52 2021 +0000
+++ b/sys/dev/audio/audio.c     Tue Jun 01 21:12:24 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: audio.c,v 1.95 2021/05/02 21:37:32 nia Exp $   */
+/*     $NetBSD: audio.c,v 1.96 2021/06/01 21:12:24 riastradh Exp $     */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -138,7 +138,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.95 2021/05/02 21:37:32 nia Exp $");
+__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.96 2021/06/01 21:12:24 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "audio.h"
@@ -2237,10 +2237,20 @@ audio_open(dev_t dev, struct audio_softc
        af = kmem_zalloc(sizeof(audio_file_t), KM_SLEEP);
        af->sc = sc;
        af->dev = dev;
-       if ((flags & FWRITE) != 0 && audio_can_playback(sc))
+       if (flags & FWRITE) {
+               if (!audio_can_playback(sc)) {
+                       error = ENXIO;
+                       goto bad;
+               }
                af->mode |= AUMODE_PLAY | AUMODE_PLAY_ALL;
-       if ((flags & FREAD) != 0 && audio_can_capture(sc))
+       }
+       if (flags & FREAD) {
+               if (!audio_can_capture(sc)) {
+                       error = ENXIO;
+                       goto bad;
+               }
                af->mode |= AUMODE_RECORD;
+       }
        if (af->mode == 0) {
                error = ENXIO;
                goto bad;