vt_ioctl.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,220 行 · 第 1/2 页

	/* the ioctls below read/set the flags usually shown in the leds */
	/* don't use them - they will go away without warning */
	case KDGKBLED:
		ucval = kbd->ledflagstate | (kbd->default_ledflagstate << 4);
		goto setchar;

	case KDSKBLED:
		if (!perm)
			return -EPERM;
		if (arg & ~0x77)
			return -EINVAL;
		kbd->ledflagstate = (arg & 7);
		kbd->default_ledflagstate = ((arg >> 4) & 7);
		set_leds();
		return 0;

	/* the ioctls below only set the lights, not the functions */
	/* for those, see KDGKBLED and KDSKBLED above */
	case KDGETLED:
		ucval = getledstate();
	setchar:
		return put_user(ucval, (char __user *)arg);

	case KDSETLED:
		if (!perm)
		  return -EPERM;
		setledstate(kbd, arg);
		return 0;

	/*
	 * A process can indicate its willingness to accept signals
	 * generated by pressing an appropriate key combination.
	 * Thus, one can have a daemon that e.g. spawns a new console
	 * upon a keypress and then changes to it.
	 * See also the kbrequest field of inittab(5).
	 */
	case KDSIGACCEPT:
	{
		extern int spawnpid, spawnsig;
		if (!perm || !capable(CAP_KILL))
		  return -EPERM;
		if (arg < 1 || arg > _NSIG || arg == SIGKILL)
		  return -EINVAL;
		spawnpid = current->pid;
		spawnsig = arg;
		return 0;
	}

	case VT_SETMODE:
	{
		struct vt_mode tmp;

		if (!perm)
			return -EPERM;
		if (copy_from_user(&tmp, up, sizeof(struct vt_mode)))
			return -EFAULT;
		if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS)
			return -EINVAL;
		acquire_console_sem();
		vt_cons[console]->vt_mode = tmp;
		/* the frsig is ignored, so we set it to 0 */
		vt_cons[console]->vt_mode.frsig = 0;
		vt_cons[console]->vt_pid = current->pid;
		/* no switch is required -- [e-mail] */
		vt_cons[console]->vt_newvt = -1; 
		release_console_sem();
		return 0;
	}

	case VT_GETMODE:
	{
		struct vt_mode tmp;
		int rc;

		acquire_console_sem();
		memcpy(&tmp, &vt_cons[console]->vt_mode, sizeof(struct vt_mode));
		release_console_sem();

		rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
		return rc ? -EFAULT : 0;
	}

	/*
	 * Returns global vt state. Note that VT 0 is always open, since
	 * it's an alias for the current VT, and people can't use it here.
	 * We cannot return state for more than 16 VTs, since v_state is short.
	 */
	case VT_GETSTATE:
	{
		struct vt_stat __user *vtstat = up;
		unsigned short state, mask;

		if (put_user(fg_console + 1, &vtstat->v_active))
			return -EFAULT;
		state = 1;	/* /dev/tty0 is always open */
		for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask; ++i, mask <<= 1)
			if (VT_IS_IN_USE(i))
				state |= mask;
		return put_user(state, &vtstat->v_state);
	}

	/*
	 * Returns the first available (non-opened) console.
	 */
	case VT_OPENQRY:
		for (i = 0; i < MAX_NR_CONSOLES; ++i)
			if (! VT_IS_IN_USE(i))
				break;
		ucval = i < MAX_NR_CONSOLES ? (i+1) : -1;
		goto setint;		 

	/*
	 * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
	 * with num >= 1 (switches to vt 0, our console, are not allowed, just
	 * to preserve sanity).
	 */
	case VT_ACTIVATE:
		if (!perm)
			return -EPERM;
		if (arg == 0 || arg > MAX_NR_CONSOLES)
			return -ENXIO;
		arg--;
		acquire_console_sem();
		i = vc_allocate(arg);
		release_console_sem();
		if (i)
			return i;
		set_console(arg);
		return 0;

	/*
	 * wait until the specified VT has been activated
	 */
	case VT_WAITACTIVE:
		if (!perm)
			return -EPERM;
		if (arg == 0 || arg > MAX_NR_CONSOLES)
			return -ENXIO;
		return vt_waitactive(arg-1);

	/*
	 * If a vt is under process control, the kernel will not switch to it
	 * immediately, but postpone the operation until the process calls this
	 * ioctl, allowing the switch to complete.
	 *
	 * According to the X sources this is the behavior:
	 *	0:	pending switch-from not OK
	 *	1:	pending switch-from OK
	 *	2:	completed switch-to OK
	 */
	case VT_RELDISP:
		if (!perm)
			return -EPERM;
		if (vt_cons[console]->vt_mode.mode != VT_PROCESS)
			return -EINVAL;

		/*
		 * Switching-from response
		 */
		if (vt_cons[console]->vt_newvt >= 0)
		{
			if (arg == 0)
				/*
				 * Switch disallowed, so forget we were trying
				 * to do it.
				 */
				vt_cons[console]->vt_newvt = -1;

			else
			{
				/*
				 * The current vt has been released, so
				 * complete the switch.
				 */
				int newvt;
				acquire_console_sem();
				newvt = vt_cons[console]->vt_newvt;
				vt_cons[console]->vt_newvt = -1;
				i = vc_allocate(newvt);
				if (i) {
					release_console_sem();
					return i;
				}
				/*
				 * When we actually do the console switch,
				 * make sure we are atomic with respect to
				 * other console switches..
				 */
				complete_change_console(newvt);
				release_console_sem();
			}
		}

		/*
		 * Switched-to response
		 */
		else
		{
			/*
			 * If it's just an ACK, ignore it
			 */
			if (arg != VT_ACKACQ)
				return -EINVAL;
		}

		return 0;

	 /*
	  * Disallocate memory associated to VT (but leave VT1)
	  */
	 case VT_DISALLOCATE:
		if (arg > MAX_NR_CONSOLES)
			return -ENXIO;
		if (arg == 0) {
		    /* disallocate all unused consoles, but leave 0 */
			acquire_console_sem();
			for (i=1; i<MAX_NR_CONSOLES; i++)
				if (! VT_BUSY(i))
					vc_disallocate(i);
			release_console_sem();
		} else {
			/* disallocate a single console, if possible */
			arg--;
			if (VT_BUSY(arg))
				return -EBUSY;
			if (arg) {			      /* leave 0 */
				acquire_console_sem();
				vc_disallocate(arg);
				release_console_sem();
			}
		}
		return 0;

	case VT_RESIZE:
	{
		struct vt_sizes __user *vtsizes = up;
		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++) {
			acquire_console_sem();
                        vc_resize(i, cc, ll);
			release_console_sem();
		}
		return 0;
	}

	case VT_RESIZEX:
	{
		struct vt_consize __user *vtconsize = up;
		ushort ll,cc,vlin,clin,vcol,ccol;
		if (!perm)
			return -EPERM;
		if (verify_area(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_resize(i, 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(fg_console, &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(fg_console, &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(fg_console, &op);
		if (i) return i;
		con_set_default_unimap(fg_console);
		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(console, &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(console, &ui);
		return 0;
	      }

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

	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;
	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.
 */
int vt_waitactive(int vt)
{
	int retval;
	DECLARE_WAITQUEUE(wait, current);

	add_wait_queue(&vt_activate_queue, &wait);
	for (;;) {
		set_current_state(TASK_INTERRUPTIBLE);
		retval = 0;
		if (vt == fg_console)
			break;
		retval = -EINTR;
		if (signal_pending(current))
			break;
		schedule();
	}
	remove_wait_queue(&vt_activate_queue, &wait);
	current->state = TASK_RUNNING;
	return retval;
}

#define vt_wake_waitactive() wake_up(&vt_activate_queue)

void reset_vc(unsigned int new_console)
{
	vt_cons[new_console]->vc_mode = KD_TEXT;
	kbd_table[new_console].kbdmode = VC_XLATE;
	vt_cons[new_console]->vt_mode.mode = VT_AUTO;
	vt_cons[new_console]->vt_mode.waitv = 0;
	vt_cons[new_console]->vt_mode.relsig = 0;
	vt_cons[new_console]->vt_mode.acqsig = 0;
	vt_cons[new_console]->vt_mode.frsig = 0;
	vt_cons[new_console]->vt_pid = -1;
	vt_cons[new_console]->vt_newvt = -1;
	if (!in_interrupt())    /* Via keyboard.c:SAK() - akpm */
		reset_palette(new_console) ;
}

/*
 * Performs the back end of a vt switch
 */
void complete_change_console(unsigned int new_console)
{
	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 = vt_cons[fg_console]->vc_mode;
	switch_screen(new_console);

	/*
	 * This can't appear below a successful kill_proc().  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 != vt_cons[new_console]->vc_mode)
	{
		if (vt_cons[new_console]->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 (vt_cons[new_console]->vt_mode.mode == VT_PROCESS)
	{
		/*
		 * Send the signal as privileged - kill_proc() will
		 * tell us if the process has gone or something else
		 * is awry
		 */
		if (kill_proc(vt_cons[new_console]->vt_pid,
			      vt_cons[new_console]->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(new_console);

			if (old_vc_mode != vt_cons[new_console]->vc_mode)
			{
				if (vt_cons[new_console]->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(unsigned int new_console)
{
        if ((new_console == fg_console) || (vt_dont_switch))
                return;
        if (!vc_cons_allocated(new_console))
		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.
	 */
	if (vt_cons[fg_console]->vt_mode.mode == VT_PROCESS)
	{
		/*
		 * Send the signal as privileged - kill_proc() will
		 * tell us if the process has gone or something else
		 * is awry
		 */
		if (kill_proc(vt_cons[fg_console]->vt_pid,
			      vt_cons[fg_console]->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.
			 */
			vt_cons[fg_console]->vt_newvt = new_console;
			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(fg_console);

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

	/*
	 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
	 */
	if (vt_cons[fg_console]->vc_mode == KD_GRAPHICS)
		return;

	complete_change_console(new_console);
}