svn commit: r363784 - head/sys/dev/vt

[Jason A. Harmening]

Author: jah
Date: Sun Aug  2 20:18:37 2020
New Revision: 363784
URL: https://svnweb.freebsd.org/changeset/base/363784

Log:
  vt(4): CONS_HISTORY/CONS_CLRHIST should operate on issuing terminal
  
  Currently the CONS_HISTORY and CONS_CLRHIST ioctls modify the state of the
  active terminal instead of the terminal against which the ioctl was issued.
  Because of the way vidcontrol(1) works, these are the same in most cases.
  But a poorly-timed window switch can make them differ. This is reproducible
  by issuing e.g. 'vidcontrol -s 2 && vidcontrol -C' to switch from vty 1 to
  vty 2; teken will reset the cursor position on vty 1 but vt(4) will clear
  the history buffer of vty 2, producing an interesting state of affairs.
  
  Differential Revision:	https://reviews.freebsd.org/D25564

Modified:
  head/sys/dev/vt/vt_core.c

Modified: head/sys/dev/vt/vt_core.c
==============================================================================
--- head/sys/dev/vt/vt_core.c	Sun Aug  2 20:03:23 2020	(r363783)
+++ head/sys/dev/vt/vt_core.c	Sun Aug  2 20:18:37 2020	(r363784)
@@ -454,7 +454,7 @@ vt_window_postswitch(struct vt_window *vw)
 	return (0);
 }
 
-/* vt_late_window_switch will done VT switching for regular case. */
+/* vt_late_window_switch will do VT switching for regular case. */
 static int
 vt_late_window_switch(struct vt_window *vw)
 {
@@ -2326,12 +2326,11 @@ skip_thunk:
 	case CONS_HISTORY:
 		if (*(int *)data < 0)
 			return EINVAL;
-		if (*(int *)data != vd->vd_curwindow->vw_buf.vb_history_size)
-			vtbuf_sethistory_size(&vd->vd_curwindow->vw_buf,
-			    *(int *)data);
+		if (*(int *)data != vw->vw_buf.vb_history_size)
+			vtbuf_sethistory_size(&vw->vw_buf, *(int *)data);
 		return (0);
 	case CONS_CLRHIST:
-		vtbuf_clearhistory(&vd->vd_curwindow->vw_buf);
+		vtbuf_clearhistory(&vw->vw_buf);
 		/*
 		 * Invalidate the entire visible window; it is not guaranteed
 		 * that this operation will be immediately followed by a scroll
@@ -2339,9 +2338,11 @@ skip_thunk:
 		 * to remain visible.
 		 */
 		VT_LOCK(vd);
-		vd->vd_flags |= VDF_INVALID;
+		if (vw == vd->vd_curwindow) {
+			vd->vd_flags |= VDF_INVALID;
+			vt_resume_flush_timer(vw, 0);
+		}
 		VT_UNLOCK(vd);
-		vt_resume_flush_timer(vd->vd_curwindow, 0);
 		return (0);
 	case CONS_GET:
 		/* XXX */