Only handle _PC_MAX_CANON, _PC_MAX_INPUT, and _PC_VDISABLE for TTY devices.

Move handling of these three pathconf() variables out of vop_stdpathconf()
and into devfs_pathconf() as TTY devices can only be devfs files.  In
addition, only return settings for these three variables for devfs devices
whose device switch has the D_TTY flag set.

Discussed with:	bde, kib
Sponsored by:	Chelsio Communications

2 files changed, 18 insertions, 9 deletions

diff --git a/sys/fs/devfs/devfs_vnops.c b/sys/fs/devfs/devfs_vnops.c
index 18b962eadffc..b30b65e2e582 100644
--- a/sys/fs/devfs/devfs_vnops.c
+++ b/sys/fs/devfs/devfs_vnops.c
@@ -1178,6 +1178,24 @@ devfs_pathconf(struct vop_pathconf_args *ap)
 {
 
 	switch (ap->a_name) {
+	case _PC_MAX_CANON:
+		if (ap->a_vp->v_vflag & VV_ISTTY) {
+			*ap->a_retval = MAX_CANON;
+			return (0);
+		}
+		return (EINVAL);
+	case _PC_MAX_INPUT:
+		if (ap->a_vp->v_vflag & VV_ISTTY) {
+			*ap->a_retval = MAX_INPUT;
+			return (0);
+		}
+		return (EINVAL);
+	case _PC_VDISABLE:
+		if (ap->a_vp->v_vflag & VV_ISTTY) {
+			*ap->a_retval = _POSIX_VDISABLE;
+			return (0);
+		}
+		return (EINVAL);
 	case _PC_MAC_PRESENT:
 #ifdef MAC
 		/*
diff --git a/sys/kern/vfs_default.c b/sys/kern/vfs_default.c
index 5c343e7f3ffc..608cbad1ffc8 100644
--- a/sys/kern/vfs_default.c
+++ b/sys/kern/vfs_default.c
@@ -486,21 +486,12 @@ vop_stdpathconf(ap)
 		case _PC_LINK_MAX:
 			*ap->a_retval = LINK_MAX;
 			return (0);
-		case _PC_MAX_CANON:
-			*ap->a_retval = MAX_CANON;
-			return (0);
-		case _PC_MAX_INPUT:
-			*ap->a_retval = MAX_INPUT;
-			return (0);
 		case _PC_PIPE_BUF:
 			*ap->a_retval = PIPE_BUF;
 			return (0);
 		case _PC_CHOWN_RESTRICTED:
 			*ap->a_retval = 1;
 			return (0);
-		case _PC_VDISABLE:
-			*ap->a_retval = _POSIX_VDISABLE;
-			return (0);
 		default:
 			return (EINVAL);
 	}