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Prevent switching to NULL or own window in the "vt_proc_window_switch"

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function. This fixes an issue where X11 keyboard input can appear
stuck. The cause of the problem is a duplicate TTY device window
switch IOCTL during boot, which leaves the "vt_switch_timer" running,
because the current window is already selected. While at it factor out
some NULL checks.

PR:			200032
Differential Revision:	https://reviews.freebsd.org/D2480
Reported by:		several people
MFC after:		1 week
Reviewed by:		emaste
This commit is contained in:
hselasky 2015-05-08 16:19:01 +00:00
parent 57645743ad
commit d0e1b4c12c
1 changed files with 29 additions and 11 deletions
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40
sys/dev/vt/vt_core.c
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@ -451,12 +451,35 @@ vt_proc_window_switch(struct vt_window *vw)
struct vt_device *vd;
int ret;
/* Prevent switching to NULL */
if (vw == NULL) {
DPRINTF(30, "%s: Cannot switch: vw is NULL.", __func__);
return (EINVAL);
}
vd = vw->vw_device;
curvw = vd->vd_curwindow;
/* Check if virtual terminal is locked */
if (curvw->vw_flags & VWF_VTYLOCK)
return (EBUSY);
/* Check if switch already in progress */
if (curvw->vw_flags & VWF_SWWAIT_REL) {
/* Check if switching to same window */
if (curvw->vw_switch_to == vw) {
DPRINTF(30, "%s: Switch in progress to same vw.", __func__);
return (0); /* success */
}
DPRINTF(30, "%s: Switch in progress to different vw.", __func__);
return (EBUSY);
}
/* Avoid switching to already selected window */
if (vw == curvw) {
DPRINTF(30, "%s: Cannot switch: vw == curvw.", __func__);
return (0); /* success */
}
/* Ask current process permission to switch away. */
if (curvw->vw_smode.mode == VT_PROCESS) {
DPRINTF(30, "%s: VT_PROCESS ", __func__);
@ -664,8 +687,7 @@ vt_scrollmode_kbdevent(struct vt_window *vw, int c, int console)
if (console == 0) {
if (c >= F_SCR && c <= MIN(L_SCR, F_SCR + VT_MAXWINDOWS - 1)) {
vw = vd->vd_windows[c - F_SCR];
if (vw != NULL)
vt_proc_window_switch(vw);
vt_proc_window_switch(vw);
return;
}
VT_LOCK(vd);
@ -750,8 +772,7 @@ vt_processkey(keyboard_t *kbd, struct vt_device *vd, int c)
if (c >= F_SCR && c <= MIN(L_SCR, F_SCR + VT_MAXWINDOWS - 1)) {
vw = vd->vd_windows[c - F_SCR];
if (vw != NULL)
vt_proc_window_switch(vw);
vt_proc_window_switch(vw);
return (0);
}
@ -760,15 +781,13 @@ vt_processkey(keyboard_t *kbd, struct vt_device *vd, int c)
/* Switch to next VT. */
c = (vw->vw_number + 1) % VT_MAXWINDOWS;
vw = vd->vd_windows[c];
if (vw != NULL)
vt_proc_window_switch(vw);
vt_proc_window_switch(vw);
return (0);
case PREV:
/* Switch to previous VT. */
c = (vw->vw_number - 1) % VT_MAXWINDOWS;
vw = vd->vd_windows[c];
if (vw != NULL)
vt_proc_window_switch(vw);
vt_proc_window_switch(vw);
return (0);
case SLK: {
vt_save_kbd_state(vw, kbd);
@ -2774,8 +2793,7 @@ vt_resume(struct vt_device *vd)
if (vt_suspendswitch == 0)
return;
/* Switch back to saved window */
if (vd->vd_savedwindow != NULL)
vt_proc_window_switch(vd->vd_savedwindow);
/* Switch back to saved window, if any */
vt_proc_window_switch(vd->vd_savedwindow);
vd->vd_savedwindow = NULL;
}