vt.c

powerpc内核mpc8241linux系统下char驱动程序

	/*
	 * To have permissions to do most of the vt ioctls, we either have
	 * to be the owner of the tty, or super-user.
	 */
	perm = 0;
	if (current->tty == tty || suser())
		perm = 1;
 
	kbd = kbd_table + console;
	switch (cmd) {
	case KIOCSOUND:
		if (!perm)
			return -EPERM;
		if (arg)
			arg = 1193180 / arg;
		kd_mksound(arg, 0);
		return 0;

	case KDMKTONE:
		if (!perm)
			return -EPERM;
	{
		unsigned int ticks, count;
		
		/*
		 * Generate the tone for the appropriate number of ticks.
		 * If the time is zero, turn off sound ourselves.
		 */
		ticks = HZ * ((arg >> 16) & 0xffff) / 1000;
		count = ticks ? (arg & 0xffff) : 0;
		if (count)
			count = 1193180 / count;
		kd_mksound(count, ticks);
		return 0;
	}

	case KDGKBTYPE:
		/*
		 * this is naive.
		 */
		ucval = keyboard_type;
		goto setchar;

#ifndef __alpha__
		/*
		 * These cannot be implemented on any machine that implements
		 * ioperm() in user level (such as Alpha PCs).
		 */
	case KDADDIO:
	case KDDELIO:
		/*
		 * KDADDIO and KDDELIO may be able to add ports beyond what
		 * we reject here, but to be safe...
		 */
		if (arg < GPFIRST || arg > GPLAST)
			return -EINVAL;
		return sys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;

	case KDENABIO:
	case KDDISABIO:
		return sys_ioperm(GPFIRST, GPNUM,
				  (cmd == KDENABIO)) ? -ENXIO : 0;
#endif

	case KDSETMODE:
		/*
		 * currently, setting the mode from KD_TEXT to KD_GRAPHICS
		 * doesn't do a whole lot. i'm not sure if it should do any
		 * restoration of modes or what...
		 */
		if (!perm)
			return -EPERM;
		switch (arg) {
		case KD_GRAPHICS:
			break;
		case KD_TEXT0:
		case KD_TEXT1:
			arg = KD_TEXT;
		case KD_TEXT:
			break;
		default:
			return -EINVAL;
		}
		if (vt_cons[console]->vc_mode == (unsigned char) arg)
			return 0;
		vt_cons[console]->vc_mode = (unsigned char) arg;
		if (console != fg_console)
			return 0;
		/*
		 * explicitly blank/unblank the screen if switching modes
		 */
		if (arg == KD_TEXT)
			unblank_screen();
		else
			do_blank_screen(1);
		return 0;

	case KDGETMODE:
		ucval = vt_cons[console]->vc_mode;
		goto setint;

	case KDMAPDISP:
	case KDUNMAPDISP:
		/*
		 * these work like a combination of mmap and KDENABIO.
		 * this could be easily finished.
		 */
		return -EINVAL;

	case KDSKBMODE:
		if (!perm)
			return -EPERM;
		switch(arg) {
		  case K_RAW:
			kbd->kbdmode = VC_RAW;
			break;
		  case K_MEDIUMRAW:
			kbd->kbdmode = VC_MEDIUMRAW;
			break;
		  case K_XLATE:
			kbd->kbdmode = VC_XLATE;
			compute_shiftstate();
			break;
		  case K_UNICODE:
			kbd->kbdmode = VC_UNICODE;
			compute_shiftstate();
			break;
		  default:
			return -EINVAL;
		}
		if (tty->ldisc.flush_buffer)
			tty->ldisc.flush_buffer(tty);
		return 0;

	case KDGKBMODE:
		ucval = ((kbd->kbdmode == VC_RAW) ? K_RAW :
				 (kbd->kbdmode == VC_MEDIUMRAW) ? K_MEDIUMRAW :
				 (kbd->kbdmode == VC_UNICODE) ? K_UNICODE :
				 K_XLATE);
		goto setint;

	/* this could be folded into KDSKBMODE, but for compatibility
	   reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
	case KDSKBMETA:
		switch(arg) {
		  case K_METABIT:
			clr_vc_kbd_mode(kbd, VC_META);
			break;
		  case K_ESCPREFIX:
			set_vc_kbd_mode(kbd, VC_META);
			break;
		  default:
			return -EINVAL;
		}
		return 0;

	case KDGKBMETA:
		ucval = (vc_kbd_mode(kbd, VC_META) ? K_ESCPREFIX : K_METABIT);
	setint:
		return put_user(ucval, (int *)arg); 

	case KDGETKEYCODE:
	case KDSETKEYCODE:
		return do_kbkeycode_ioctl(cmd, (struct kbkeycode *)arg, perm);

	case KDGKBENT:
	case KDSKBENT:
		return do_kdsk_ioctl(cmd, (struct kbentry *)arg, perm, kbd);

	case KDGKBSENT:
	case KDSKBSENT:
		return do_kdgkb_ioctl(cmd, (struct kbsentry *)arg, perm);

	case KDGKBDIACR:
	{
		struct kbdiacrs *a = (struct kbdiacrs *)arg;

		if (put_user(accent_table_size, &a->kb_cnt))
			return -EFAULT;
		if (copy_to_user(a->kbdiacr, accent_table, accent_table_size*sizeof(struct kbdiacr)))
			return -EFAULT;
		return 0;
	}

	case KDSKBDIACR:
	{
		struct kbdiacrs *a = (struct kbdiacrs *)arg;
		unsigned int ct;

		if (!perm)
			return -EPERM;
		if (get_user(ct,&a->kb_cnt))
			return -EFAULT;
		if (ct >= MAX_DIACR)
			return -EINVAL;
		accent_table_size = ct;
		if (copy_from_user(accent_table, a->kbdiacr, ct*sizeof(struct kbdiacr)))
			return -EFAULT;
		return 0;
	}

	/* 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*)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.
	 * Probably init should be changed to do this (and have a
	 * field ks (`keyboard signal') in inittab describing the
	 * desired action), so that the number of background daemons
	 * does not increase.
	 */
	case KDSIGACCEPT:
	{
		extern int spawnpid, spawnsig;
		if (!perm)
		  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, (void*)arg, sizeof(struct vt_mode)))
			return -EFAULT;
		if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS)
			return -EINVAL;
		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; 
		return 0;
	}

	case VT_GETMODE:
		return copy_to_user((void*)arg, &(vt_cons[console]->vt_mode), 
							sizeof(struct vt_mode)) ? -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 *vtstat = (struct vt_stat *)arg;
		unsigned short state, mask;

		i = verify_area(VERIFY_WRITE,(void *)vtstat, sizeof(struct vt_stat));
		if (i)
			return i;
		put_user(fg_console + 1, &vtstat->v_active);
		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--;
		i = vc_allocate(arg);
		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 = vt_cons[console]->vt_newvt;
				vt_cons[console]->vt_newvt = -1;
				i = vc_allocate(newvt);
				if (i)
					return i;
				/*
				 * When we actually do the console switch,
				 * make sure we are atomic with respect to
				 * other console switches..
				 */
				start_bh_atomic();
				complete_change_console(newvt);
				end_bh_atomic();
			}
		}

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

	case VT_RESIZE:
	{
		struct vt_sizes *vtsizes = (struct vt_sizes *) arg;
		ushort ll,cc;
		if (!perm)
			return -EPERM;
		i = verify_area(VERIFY_READ, (void *)vtsizes, sizeof(struct vt_sizes));
		if (i)