vt_ioctl.c

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			acquire_console_sem();
			for (i=1; i<MAX_NR_CONSOLES; i++)
				if (! VT_BUSY(i))
					vc_deallocate(i);
			release_console_sem();
		} else {
			/* deallocate a single console, if possible */
			arg--;
			if (VT_BUSY(arg))
				return -EBUSY;
			if (arg) {			      /* leave 0 */
				acquire_console_sem();
				vc_deallocate(arg);
				release_console_sem();
			}
		}
		return 0;

	case VT_RESIZE:
	{
		struct vt_sizes __user *vtsizes = up;
		struct vc_data *vc;

		ushort ll,cc;
		if (!perm)
			return -EPERM;
		if (get_user(ll, &vtsizes->v_rows) ||
		    get_user(cc, &vtsizes->v_cols))
			return -EFAULT;

		for (i = 0; i < MAX_NR_CONSOLES; i++) {
			vc = vc_cons[i].d;

			if (vc) {
				vc->vc_resize_user = 1;
				vc_lock_resize(vc_cons[i].d, cc, ll);
			}
		}

		return 0;
	}

	case VT_RESIZEX:
	{
		struct vt_consize __user *vtconsize = up;
		ushort ll,cc,vlin,clin,vcol,ccol;
		if (!perm)
			return -EPERM;
		if (!access_ok(VERIFY_READ, vtconsize,
				sizeof(struct vt_consize)))
			return -EFAULT;
		__get_user(ll, &vtconsize->v_rows);
		__get_user(cc, &vtconsize->v_cols);
		__get_user(vlin, &vtconsize->v_vlin);
		__get_user(clin, &vtconsize->v_clin);
		__get_user(vcol, &vtconsize->v_vcol);
		__get_user(ccol, &vtconsize->v_ccol);
		vlin = vlin ? vlin : vc->vc_scan_lines;
		if (clin) {
			if (ll) {
				if (ll != vlin/clin)
					return -EINVAL; /* Parameters don't add up */
			} else 
				ll = vlin/clin;
		}
		if (vcol && ccol) {
			if (cc) {
				if (cc != vcol/ccol)
					return -EINVAL;
			} else
				cc = vcol/ccol;
		}

		if (clin > 32)
			return -EINVAL;
		    
		for (i = 0; i < MAX_NR_CONSOLES; i++) {
			if (!vc_cons[i].d)
				continue;
			acquire_console_sem();
			if (vlin)
				vc_cons[i].d->vc_scan_lines = vlin;
			if (clin)
				vc_cons[i].d->vc_font.height = clin;
			vc_cons[i].d->vc_resize_user = 1;
			vc_resize(vc_cons[i].d, cc, ll);
			release_console_sem();
		}
  		return 0;
	}

	case PIO_FONT: {
		if (!perm)
			return -EPERM;
		op.op = KD_FONT_OP_SET;
		op.flags = KD_FONT_FLAG_OLD | KD_FONT_FLAG_DONT_RECALC;	/* Compatibility */
		op.width = 8;
		op.height = 0;
		op.charcount = 256;
		op.data = up;
		return con_font_op(vc_cons[fg_console].d, &op);
	}

	case GIO_FONT: {
		op.op = KD_FONT_OP_GET;
		op.flags = KD_FONT_FLAG_OLD;
		op.width = 8;
		op.height = 32;
		op.charcount = 256;
		op.data = up;
		return con_font_op(vc_cons[fg_console].d, &op);
	}

	case PIO_CMAP:
                if (!perm)
			return -EPERM;
                return con_set_cmap(up);

	case GIO_CMAP:
                return con_get_cmap(up);

	case PIO_FONTX:
	case GIO_FONTX:
		return do_fontx_ioctl(cmd, up, perm, &op);

	case PIO_FONTRESET:
	{
		if (!perm)
			return -EPERM;

#ifdef BROKEN_GRAPHICS_PROGRAMS
		/* With BROKEN_GRAPHICS_PROGRAMS defined, the default
		   font is not saved. */
		return -ENOSYS;
#else
		{
		op.op = KD_FONT_OP_SET_DEFAULT;
		op.data = NULL;
		i = con_font_op(vc_cons[fg_console].d, &op);
		if (i)
			return i;
		con_set_default_unimap(vc_cons[fg_console].d);
		return 0;
		}
#endif
	}

	case KDFONTOP: {
		if (copy_from_user(&op, up, sizeof(op)))
			return -EFAULT;
		if (!perm && op.op != KD_FONT_OP_GET)
			return -EPERM;
		i = con_font_op(vc, &op);
		if (i) return i;
		if (copy_to_user(up, &op, sizeof(op)))
			return -EFAULT;
		return 0;
	}

	case PIO_SCRNMAP:
		if (!perm)
			return -EPERM;
		return con_set_trans_old(up);

	case GIO_SCRNMAP:
		return con_get_trans_old(up);

	case PIO_UNISCRNMAP:
		if (!perm)
			return -EPERM;
		return con_set_trans_new(up);

	case GIO_UNISCRNMAP:
		return con_get_trans_new(up);

	case PIO_UNIMAPCLR:
	      { struct unimapinit ui;
		if (!perm)
			return -EPERM;
		i = copy_from_user(&ui, up, sizeof(struct unimapinit));
		if (i) return -EFAULT;
		con_clear_unimap(vc, &ui);
		return 0;
	      }

	case PIO_UNIMAP:
	case GIO_UNIMAP:
		return do_unimap_ioctl(cmd, up, perm, vc);

	case VT_LOCKSWITCH:
		if (!capable(CAP_SYS_TTY_CONFIG))
		   return -EPERM;
		vt_dont_switch = 1;
		return 0;
	case VT_UNLOCKSWITCH:
		if (!capable(CAP_SYS_TTY_CONFIG))
		   return -EPERM;
		vt_dont_switch = 0;
		return 0;
	case VT_GETHIFONTMASK:
		return put_user(vc->vc_hi_font_mask, (unsigned short __user *)arg);
	default:
		return -ENOIOCTLCMD;
	}
}

/*
 * Sometimes we want to wait until a particular VT has been activated. We
 * do it in a very simple manner. Everybody waits on a single queue and
 * get woken up at once. Those that are satisfied go on with their business,
 * while those not ready go back to sleep. Seems overkill to add a wait
 * to each vt just for this - usually this does nothing!
 */
static DECLARE_WAIT_QUEUE_HEAD(vt_activate_queue);

/*
 * Sleeps until a vt is activated, or the task is interrupted. Returns
 * 0 if activation, -EINTR if interrupted by a signal handler.
 */
int vt_waitactive(int vt)
{
	int retval;
	DECLARE_WAITQUEUE(wait, current);

	add_wait_queue(&vt_activate_queue, &wait);
	for (;;) {
		retval = 0;

		/*
		 * Synchronize with redraw_screen(). By acquiring the console
		 * semaphore we make sure that the console switch is completed
		 * before we return. If we didn't wait for the semaphore, we
		 * could return at a point where fg_console has already been
		 * updated, but the console switch hasn't been completed.
		 */
		acquire_console_sem();
		set_current_state(TASK_INTERRUPTIBLE);
		if (vt == fg_console) {
			release_console_sem();
			break;
		}
		release_console_sem();
		retval = -ERESTARTNOHAND;
		if (signal_pending(current))
			break;
		schedule();
	}
	remove_wait_queue(&vt_activate_queue, &wait);
	__set_current_state(TASK_RUNNING);
	return retval;
}

#define vt_wake_waitactive() wake_up(&vt_activate_queue)

void reset_vc(struct vc_data *vc)
{
	vc->vc_mode = KD_TEXT;
	kbd_table[vc->vc_num].kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE;
	vc->vt_mode.mode = VT_AUTO;
	vc->vt_mode.waitv = 0;
	vc->vt_mode.relsig = 0;
	vc->vt_mode.acqsig = 0;
	vc->vt_mode.frsig = 0;
	put_pid(vc->vt_pid);
	vc->vt_pid = NULL;
	vc->vt_newvt = -1;
	if (!in_interrupt())    /* Via keyboard.c:SAK() - akpm */
		reset_palette(vc);
}

void vc_SAK(struct work_struct *work)
{
	struct vc *vc_con =
		container_of(work, struct vc, SAK_work);
	struct vc_data *vc;
	struct tty_struct *tty;

	acquire_console_sem();
	vc = vc_con->d;
	if (vc) {
		tty = vc->vc_tty;
		/*
		 * SAK should also work in all raw modes and reset
		 * them properly.
		 */
		if (tty)
			__do_SAK(tty);
		reset_vc(vc);
	}
	release_console_sem();
}

/*
 * Performs the back end of a vt switch
 */
static void complete_change_console(struct vc_data *vc)
{
	unsigned char old_vc_mode;

	last_console = fg_console;

	/*
	 * If we're switching, we could be going from KD_GRAPHICS to
	 * KD_TEXT mode or vice versa, which means we need to blank or
	 * unblank the screen later.
	 */
	old_vc_mode = vc_cons[fg_console].d->vc_mode;
	switch_screen(vc);

	/*
	 * This can't appear below a successful kill_pid().  If it did,
	 * then the *blank_screen operation could occur while X, having
	 * received acqsig, is waking up on another processor.  This
	 * condition can lead to overlapping accesses to the VGA range
	 * and the framebuffer (causing system lockups).
	 *
	 * To account for this we duplicate this code below only if the
	 * controlling process is gone and we've called reset_vc.
	 */
	if (old_vc_mode != vc->vc_mode) {
		if (vc->vc_mode == KD_TEXT)
			do_unblank_screen(1);
		else
			do_blank_screen(1);
	}

	/*
	 * If this new console is under process control, send it a signal
	 * telling it that it has acquired. Also check if it has died and
	 * clean up (similar to logic employed in change_console())
	 */
	if (vc->vt_mode.mode == VT_PROCESS) {
		/*
		 * Send the signal as privileged - kill_pid() will
		 * tell us if the process has gone or something else
		 * is awry
		 */
		if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
		/*
		 * The controlling process has died, so we revert back to
		 * normal operation. In this case, we'll also change back
		 * to KD_TEXT mode. I'm not sure if this is strictly correct
		 * but it saves the agony when the X server dies and the screen
		 * remains blanked due to KD_GRAPHICS! It would be nice to do
		 * this outside of VT_PROCESS but there is no single process
		 * to account for and tracking tty count may be undesirable.
		 */
			reset_vc(vc);

			if (old_vc_mode != vc->vc_mode) {
				if (vc->vc_mode == KD_TEXT)
					do_unblank_screen(1);
				else
					do_blank_screen(1);
			}
		}
	}

	/*
	 * Wake anyone waiting for their VT to activate
	 */
	vt_wake_waitactive();
	return;
}

/*
 * Performs the front-end of a vt switch
 */
void change_console(struct vc_data *new_vc)
{
	struct vc_data *vc;

	if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
		return;

	/*
	 * If this vt is in process mode, then we need to handshake with
	 * that process before switching. Essentially, we store where that
	 * vt wants to switch to and wait for it to tell us when it's done
	 * (via VT_RELDISP ioctl).
	 *
	 * We also check to see if the controlling process still exists.
	 * If it doesn't, we reset this vt to auto mode and continue.
	 * This is a cheap way to track process control. The worst thing
	 * that can happen is: we send a signal to a process, it dies, and
	 * the switch gets "lost" waiting for a response; hopefully, the
	 * user will try again, we'll detect the process is gone (unless
	 * the user waits just the right amount of time :-) and revert the
	 * vt to auto control.
	 */
	vc = vc_cons[fg_console].d;
	if (vc->vt_mode.mode == VT_PROCESS) {
		/*
		 * Send the signal as privileged - kill_pid() will
		 * tell us if the process has gone or something else
		 * is awry.
		 *
		 * We need to set vt_newvt *before* sending the signal or we
		 * have a race.
		 */
		vc->vt_newvt = new_vc->vc_num;
		if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
			/*
			 * It worked. Mark the vt to switch to and
			 * return. The process needs to send us a
			 * VT_RELDISP ioctl to complete the switch.
			 */
			return;
		}

		/*
		 * The controlling process has died, so we revert back to
		 * normal operation. In this case, we'll also change back
		 * to KD_TEXT mode. I'm not sure if this is strictly correct
		 * but it saves the agony when the X server dies and the screen
		 * remains blanked due to KD_GRAPHICS! It would be nice to do
		 * this outside of VT_PROCESS but there is no single process
		 * to account for and tracking tty count may be undesirable.
		 */
		reset_vc(vc);

		/*
		 * Fall through to normal (VT_AUTO) handling of the switch...
		 */
	}

	/*
	 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
	 */
	if (vc->vc_mode == KD_GRAPHICS)
		return;

	complete_change_console(new_vc);
}