[PATCH] vt: Drop K_OFF for VC_MUTE

[Adam Jackson]

The "don't enqueue stuff" semantics of K_OFF shouldn't be a function of
the keyboard map state; we should be able to switch among cooked/raw/
unicode without changing whether events are delivered.  Otherwise - if
changing to K_UNICODE undoes K_OFF - then suddenly Alt-F2 under
Gnome will switch VT instead of summoning the "run command" dialog.

Drop the K_OFF handling and replace it with a new "mute" ioctl pair.
Anybody using K_OFF would already need to be prepared to handle it
throwing -EINVAL for old kernel compatibility, so userspace will degrade
gracefully.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=859485
Cc: Arthur Taylor <art@xxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Tested-by: Josh Boyer <jwboyer@xxxxxxxxxx>
Signed-off-by: Adam Jackson <ajax@xxxxxxxxxx>
---
 drivers/tty/vt/keyboard.c | 40 +++++++++++++++++++++++++++++++++-------
 drivers/tty/vt/vt_ioctl.c | 13 +++++++++++++
 include/linux/kbd_kern.h  |  6 +++---
 include/linux/vt_kern.h   |  2 ++
 include/uapi/linux/kd.h   |  5 +++++
 5 files changed, 56 insertions(+), 10 deletions(-)

diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index 681765b..08d1d57 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -657,7 +657,7 @@ static void k_spec(struct vc_data *vc, unsigned char value, char up_flag)
 		return;
 	if ((kbd->kbdmode == VC_RAW ||
 	     kbd->kbdmode == VC_MEDIUMRAW ||
-	     kbd->kbdmode == VC_OFF) &&
+	     vc_kbd_mode(kbd, VC_MUTE)) &&
 	     value != KVAL(K_SAK))
 		return;		/* SAK is allowed even in raw mode */
 	fn_handler[value](vc);
@@ -1381,7 +1381,7 @@ static void kbd_keycode(unsigned int keycode, int down, int hw_raw)
 	if (rc == NOTIFY_STOP)
 		return;
 
-	if ((raw_mode || kbd->kbdmode == VC_OFF) && type != KT_SPEC && type != KT_SHIFT)
+	if ((raw_mode || vc_kbd_mode(kbd, VC_MUTE)) && type != KT_SPEC && type != KT_SHIFT)
 		return;
 
 	(*k_handler[type])(vc, keysym & 0xff, !down);
@@ -1731,9 +1731,6 @@ int vt_do_kdskbmode(int console, unsigned int arg)
 		kbd->kbdmode = VC_UNICODE;
 		do_compute_shiftstate();
 		break;
-	case K_OFF:
-		kbd->kbdmode = VC_OFF;
-		break;
 	default:
 		ret = -EINVAL;
 	}
@@ -1742,6 +1739,30 @@ int vt_do_kdskbmode(int console, unsigned int arg)
 }
 
 /**
+ *	vt_do_kdskbmute		-	set keyboard event mute
+ *	@console: the console to use
+ *	@arg: the requested mode
+ *
+ *	Update the keyboard mute state while holding the correct locks.
+ *	Return 0 for success or an error code.
+ */
+int vt_do_kdskbmute(int console, unsigned int arg)
+{
+	struct kbd_struct * kbd = kbd_table + console;
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&kbd_event_lock, flags);
+	if (arg)
+		set_vc_kbd_mode(kbd, VC_MUTE);
+	else
+		clr_vc_kbd_mode(kbd, VC_MUTE);
+	spin_unlock_irqrestore(&kbd_event_lock, flags);
+	return ret;
+}
+
+
+/**
  *	vt_do_kdskbmeta		-	set keyboard meta state
  *	@console: the console to use
  *	@arg: the requested meta state
@@ -2068,13 +2089,18 @@ int vt_do_kdgkbmode(int console)
 		return K_MEDIUMRAW;
 	case VC_UNICODE:
 		return K_UNICODE;
-	case VC_OFF:
-		return K_OFF;
 	default:
 		return K_XLATE;
 	}
 }
 
+int vt_do_kgdbmute(int console)
+{
+	struct kbd_struct * kbd = kbd_table + console;
+	/* This is a spot read so needs no locking */
+	return vc_kbd_mode(kbd, VC_MUTE);
+}
+
 /**
  *	vt_do_kdgkbmeta		-	report meta status
  *	@console: console to report
diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c
index b841f56..f0951e2 100644
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -477,6 +477,19 @@ int vt_ioctl(struct tty_struct *tty,
 		ret = put_user(uival, (int __user *)arg);
 		break;
 
+	case KDSKBMUTE:
+		if (!perm)
+			return -EPERM;
+		ret = vt_do_kdskbmute(console, arg);
+		if (ret == 0)
+			tty_ldisc_flush(tty);
+		break;
+
+	case KDGKBMUTE:
+		uival = vt_do_kdgkbmute(console);
+		ret = put_user(uival, (int __user *)arg);
+		break;
+
 	/* this could be folded into KDSKBMODE, but for compatibility
 	   reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
 	case KDSKBMETA:
diff --git a/include/linux/kbd_kern.h b/include/linux/kbd_kern.h
index b7c8cdc..9386143 100644
--- a/include/linux/kbd_kern.h
+++ b/include/linux/kbd_kern.h
@@ -48,19 +48,19 @@ struct kbd_struct {
 #define VC_CAPSLOCK	2	/* capslock mode */
 #define VC_KANALOCK	3	/* kanalock mode */
 
-	unsigned char kbdmode:3;	/* one 3-bit value */
+	unsigned char kbdmode:2;	/* one 2-bit value */
 #define VC_XLATE	0	/* translate keycodes using keymap */
 #define VC_MEDIUMRAW	1	/* medium raw (keycode) mode */
 #define VC_RAW		2	/* raw (scancode) mode */
 #define VC_UNICODE	3	/* Unicode mode */
-#define VC_OFF		4	/* disabled mode */
 
-	unsigned char modeflags:5;
+	unsigned char modeflags:6;
 #define VC_APPLIC	0	/* application key mode */
 #define VC_CKMODE	1	/* cursor key mode */
 #define VC_REPEAT	2	/* keyboard repeat */
 #define VC_CRLF		3	/* 0 - enter sends CR, 1 - enter sends CRLF */
 #define VC_META		4	/* 0 - meta, 1 - meta=prefix with ESC */
+#define VC_MUTE		5	/* don't generate events */
 };
 
 extern int kbd_init(void);
diff --git a/include/linux/vt_kern.h b/include/linux/vt_kern.h
index 50ae7d0..a886915 100644
--- a/include/linux/vt_kern.h
+++ b/include/linux/vt_kern.h
@@ -168,6 +168,7 @@ extern void hide_boot_cursor(bool hide);
 
 /* keyboard  provided interfaces */
 extern int vt_do_diacrit(unsigned int cmd, void __user *up, int eperm);
+extern int vt_do_kdskbmute(int console, unsigned int arg);
 extern int vt_do_kdskbmode(int console, unsigned int arg);
 extern int vt_do_kdskbmeta(int console, unsigned int arg);
 extern int vt_do_kbkeycode_ioctl(int cmd, struct kbkeycode __user *user_kbkc,
@@ -177,6 +178,7 @@ extern int vt_do_kdsk_ioctl(int cmd, struct kbentry __user *user_kbe,
 extern int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb,
                                         int perm);
 extern int vt_do_kdskled(int console, int cmd, unsigned long arg, int perm);
+extern int vt_do_kdgkbmute(int console);
 extern int vt_do_kdgkbmode(int console);
 extern int vt_do_kdgkbmeta(int console);
 extern void vt_reset_unicode(int console);
diff --git a/include/uapi/linux/kd.h b/include/uapi/linux/kd.h
index 87b7cc4..c3de63c 100644
--- a/include/uapi/linux/kd.h
+++ b/include/uapi/linux/kd.h
@@ -81,6 +81,7 @@ struct unimapinit {
 #define		K_XLATE		0x01
 #define		K_MEDIUMRAW	0x02
 #define		K_UNICODE	0x03
+/* K_OFF is no longer implemented, but preserved for source compatibility */
 #define		K_OFF		0x04
 #define KDGKBMODE	0x4B44	/* gets current keyboard mode */
 #define KDSKBMODE	0x4B45	/* sets current keyboard mode */
@@ -150,6 +151,10 @@ struct kbd_repeat {
 			/* earlier this field was misnamed "rate" */
 };
 
+/* get/set event mute */
+#define KDGKBMUTE	0x4B50
+#define KDSKBMUTE	0x4B51
+
 #define KDKBDREP        0x4B52  /* set keyboard delay/repeat rate;
 				 * actually used values are returned */
 
-- 
1.7.11.7

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