Add FIONREAD to pseudo-terminal master devices.

All ioctl()'s that aren't implemented by pts(4) are forwarded to the TTY
itself. Unfortunately this is not correct for FIONREAD, because it will
give the wrong amount of bytes that are available to read.

Tested by:	keramida
Reminded by:	keramida

1 files changed, 10 insertions, 0 deletions

diff --git a/sys/kern/tty_pts.c b/sys/kern/tty_pts.c
index 9e81a6d..c767daa 100644
--- a/sys/kern/tty_pts.c
+++ b/sys/kern/tty_pts.c
@@ -273,6 +273,16 @@ ptsdev_ioctl(struct file *fp, u_long cmd, void *data,
 	case FIONBIO:
 		/* This device supports non-blocking operation. */
 		return (0);
+	case FIONREAD:
+		tty_lock(tp);
+		if (psc->pts_flags & PTS_FINISHED) {
+			/* Force read() to be called. */
+			*(int *)data = 1;
+		} else {
+			*(int *)data = ttydisc_getc_poll(tp);
+		}
+		tty_unlock(tp);
+		return (0);
 	case FIODGNAME: {
 		struct fiodgname_arg *fgn;
 		const char *p;