Commit d3b5cffc authored by Alan Cox's avatar Alan Cox Committed by Live-CD User
Browse files

vt: add an activate and lock 



X and other graphical interfaces need to be able to flip to a console
and lock it into graphics mode without races.

Signed-off-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent a5eb5624

drivers/char/vt_ioctl.c

+37 −1
Original line number Diff line number Diff line
@@ -972,6 +972,41 @@ int vt_ioctl(struct tty_struct *tty, struct file * file, 
		}

		break;



	case VT_SETACTIVATE:

	{

		struct vt_setactivate vsa;



		if (!perm)

			goto eperm;



		if (copy_from_user(&vsa, (struct vt_setactivate __user *)arg,

						sizeof(struct vt_setactivate)))

			return -EFAULT;

		if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)

			ret = -ENXIO;

		else {

			vsa.console--;

			acquire_console_sem();

			ret = vc_allocate(vsa.console);

			if (ret == 0) {

				struct vc_data *nvc;

				/* This is safe providing we don't drop the

				   console sem between vc_allocate and

				   finishing referencing nvc */

				nvc = vc_cons[vsa.console].d;

				nvc->vt_mode = vsa.mode;

				nvc->vt_mode.frsig = 0;

				put_pid(nvc->vt_pid);

				nvc->vt_pid = get_pid(task_pid(current));

			}

			release_console_sem();

			if (ret)

				break;

			/* Commence switch and lock */

			set_console(arg);

		}

	}



	/*

	 * wait until the specified VT has been activated

	 */
@@ -1342,7 +1377,8 @@ void vc_SAK(struct work_struct *work) 
}



/*

 * Performs the back end of a vt switch

 * Performs the back end of a vt switch. Called under the console

 * semaphore.

 */

static void complete_change_console(struct vc_data *vc)

{

include/linux/vt.h

+7 −0
Original line number Diff line number Diff line
@@ -77,4 +77,11 @@ struct vt_event { 


#define VT_WAITEVENT	0x560E	/* Wait for an event */



struct vt_setactivate {

	unsigned int console;

	struct vt_mode mode;

};



#define VT_SETACTIVATE	0x560F	/* Activate and set the mode of a console */



#endif /* _LINUX_VT_H */