Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1201 insertions, 0 deletions

diff --git a/drivers/char/vt_ioctl.c b/drivers/char/vt_ioctl.c
new file mode 100644
index 000000000000..5d386f4bea49
--- /dev/null
+++ b/drivers/char/vt_ioctl.c
@@ -0,0 +1,1201 @@
+/*
+ *  linux/drivers/char/vt_ioctl.c
+ *
+ *  Copyright (C) 1992 obz under the linux copyright
+ *
+ *  Dynamic diacritical handling - aeb@cwi.nl - Dec 1993
+ *  Dynamic keymap and string allocation - aeb@cwi.nl - May 1994
+ *  Restrict VT switching via ioctl() - grif@cs.ucr.edu - Dec 1995
+ *  Some code moved for less code duplication - Andi Kleen - Mar 1997
+ *  Check put/get_user, cleanups - acme@conectiva.com.br - Jun 2001
+ */
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/tty.h>
+#include <linux/timer.h>
+#include <linux/kernel.h>
+#include <linux/kd.h>
+#include <linux/vt.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/major.h>
+#include <linux/fs.h>
+#include <linux/console.h>
+
+#include <asm/io.h>
+#include <asm/uaccess.h>
+
+#include <linux/kbd_kern.h>
+#include <linux/vt_kern.h>
+#include <linux/kbd_diacr.h>
+#include <linux/selection.h>
+
+static char vt_dont_switch;
+extern struct tty_driver *console_driver;
+
+#define VT_IS_IN_USE(i)	(console_driver->ttys[i] && console_driver->ttys[i]->count)
+#define VT_BUSY(i)	(VT_IS_IN_USE(i) || i == fg_console || vc_cons[i].d == sel_cons)
+
+/*
+ * Console (vt and kd) routines, as defined by USL SVR4 manual, and by
+ * experimentation and study of X386 SYSV handling.
+ *
+ * One point of difference: SYSV vt's are /dev/vtX, which X >= 0, and
+ * /dev/console is a separate ttyp. Under Linux, /dev/tty0 is /dev/console,
+ * and the vc start at /dev/ttyX, X >= 1. We maintain that here, so we will
+ * always treat our set of vt as numbered 1..MAX_NR_CONSOLES (corresponding to
+ * ttys 0..MAX_NR_CONSOLES-1). Explicitly naming VT 0 is illegal, but using
+ * /dev/tty0 (fg_console) as a target is legal, since an implicit aliasing
+ * to the current console is done by the main ioctl code.
+ */
+
+#ifdef CONFIG_X86
+#include <linux/syscalls.h>
+#endif
+
+static void complete_change_console(struct vc_data *vc);
+
+/*
+ * these are the valid i/o ports we're allowed to change. they map all the
+ * video ports
+ */
+#define GPFIRST 0x3b4
+#define GPLAST 0x3df
+#define GPNUM (GPLAST - GPFIRST + 1)
+
+#define i (tmp.kb_index)
+#define s (tmp.kb_table)
+#define v (tmp.kb_value)
+static inline int
+do_kdsk_ioctl(int cmd, struct kbentry __user *user_kbe, int perm, struct kbd_struct *kbd)
+{
+	struct kbentry tmp;
+	ushort *key_map, val, ov;
+
+	if (copy_from_user(&tmp, user_kbe, sizeof(struct kbentry)))
+		return -EFAULT;
+
+	switch (cmd) {
+	case KDGKBENT:
+		key_map = key_maps[s];
+		if (key_map) {
+		    val = U(key_map[i]);
+		    if (kbd->kbdmode != VC_UNICODE && KTYP(val) >= NR_TYPES)
+			val = K_HOLE;
+		} else
+		    val = (i ? K_HOLE : K_NOSUCHMAP);
+		return put_user(val, &user_kbe->kb_value);
+	case KDSKBENT:
+		if (!perm)
+			return -EPERM;
+		if (!i && v == K_NOSUCHMAP) {
+			/* disallocate map */
+			key_map = key_maps[s];
+			if (s && key_map) {
+			    key_maps[s] = NULL;
+			    if (key_map[0] == U(K_ALLOCATED)) {
+					kfree(key_map);
+					keymap_count--;
+			    }
+			}
+			break;
+		}
+
+		if (KTYP(v) < NR_TYPES) {
+		    if (KVAL(v) > max_vals[KTYP(v)])
+				return -EINVAL;
+		} else
+		    if (kbd->kbdmode != VC_UNICODE)
+				return -EINVAL;
+
+		/* ++Geert: non-PC keyboards may generate keycode zero */
+#if !defined(__mc68000__) && !defined(__powerpc__)
+		/* assignment to entry 0 only tests validity of args */
+		if (!i)
+			break;
+#endif
+
+		if (!(key_map = key_maps[s])) {
+			int j;
+
+			if (keymap_count >= MAX_NR_OF_USER_KEYMAPS &&
+			    !capable(CAP_SYS_RESOURCE))
+				return -EPERM;
+
+			key_map = (ushort *) kmalloc(sizeof(plain_map),
+						     GFP_KERNEL);
+			if (!key_map)
+				return -ENOMEM;
+			key_maps[s] = key_map;
+			key_map[0] = U(K_ALLOCATED);
+			for (j = 1; j < NR_KEYS; j++)
+				key_map[j] = U(K_HOLE);
+			keymap_count++;
+		}
+		ov = U(key_map[i]);
+		if (v == ov)
+			break;	/* nothing to do */
+		/*
+		 * Attention Key.
+		 */
+		if (((ov == K_SAK) || (v == K_SAK)) && !capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		key_map[i] = U(v);
+		if (!s && (KTYP(ov) == KT_SHIFT || KTYP(v) == KT_SHIFT))
+			compute_shiftstate();
+		break;
+	}
+	return 0;
+}
+#undef i
+#undef s
+#undef v
+
+static inline int 
+do_kbkeycode_ioctl(int cmd, struct kbkeycode __user *user_kbkc, int perm)
+{
+	struct kbkeycode tmp;
+	int kc = 0;
+
+	if (copy_from_user(&tmp, user_kbkc, sizeof(struct kbkeycode)))
+		return -EFAULT;
+	switch (cmd) {
+	case KDGETKEYCODE:
+		kc = getkeycode(tmp.scancode);
+		if (kc >= 0)
+			kc = put_user(kc, &user_kbkc->keycode);
+		break;
+	case KDSETKEYCODE:
+		if (!perm)
+			return -EPERM;
+		kc = setkeycode(tmp.scancode, tmp.keycode);
+		break;
+	}
+	return kc;
+}
+
+static inline int
+do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm)
+{
+	struct kbsentry *kbs;
+	char *p;
+	u_char *q;
+	u_char __user *up;
+	int sz;
+	int delta;
+	char *first_free, *fj, *fnw;
+	int i, j, k;
+	int ret;
+
+	kbs = kmalloc(sizeof(*kbs), GFP_KERNEL);
+	if (!kbs) {
+		ret = -ENOMEM;
+		goto reterr;
+	}
+
+	/* we mostly copy too much here (512bytes), but who cares ;) */
+	if (copy_from_user(kbs, user_kdgkb, sizeof(struct kbsentry))) {
+		ret = -EFAULT;
+		goto reterr;
+	}
+	kbs->kb_string[sizeof(kbs->kb_string)-1] = '\0';
+	i = kbs->kb_func;
+
+	switch (cmd) {
+	case KDGKBSENT:
+		sz = sizeof(kbs->kb_string) - 1; /* sz should have been
+						  a struct member */
+		up = user_kdgkb->kb_string;
+		p = func_table[i];
+		if(p)
+			for ( ; *p && sz; p++, sz--)
+				if (put_user(*p, up++)) {
+					ret = -EFAULT;
+					goto reterr;
+				}
+		if (put_user('\0', up)) {
+			ret = -EFAULT;
+			goto reterr;
+		}
+		kfree(kbs);
+		return ((p && *p) ? -EOVERFLOW : 0);
+	case KDSKBSENT:
+		if (!perm) {
+			ret = -EPERM;
+			goto reterr;
+		}
+
+		q = func_table[i];
+		first_free = funcbufptr + (funcbufsize - funcbufleft);
+		for (j = i+1; j < MAX_NR_FUNC && !func_table[j]; j++) 
+			;
+		if (j < MAX_NR_FUNC)
+			fj = func_table[j];
+		else
+			fj = first_free;
+
+		delta = (q ? -strlen(q) : 1) + strlen(kbs->kb_string);
+		if (delta <= funcbufleft) { 	/* it fits in current buf */
+		    if (j < MAX_NR_FUNC) {
+			memmove(fj + delta, fj, first_free - fj);
+			for (k = j; k < MAX_NR_FUNC; k++)
+			    if (func_table[k])
+				func_table[k] += delta;
+		    }
+		    if (!q)
+		      func_table[i] = fj;
+		    funcbufleft -= delta;
+		} else {			/* allocate a larger buffer */
+		    sz = 256;
+		    while (sz < funcbufsize - funcbufleft + delta)
+		      sz <<= 1;
+		    fnw = (char *) kmalloc(sz, GFP_KERNEL);
+		    if(!fnw) {
+		      ret = -ENOMEM;
+		      goto reterr;
+		    }
+
+		    if (!q)
+		      func_table[i] = fj;
+		    if (fj > funcbufptr)
+			memmove(fnw, funcbufptr, fj - funcbufptr);
+		    for (k = 0; k < j; k++)
+		      if (func_table[k])
+			func_table[k] = fnw + (func_table[k] - funcbufptr);
+
+		    if (first_free > fj) {
+			memmove(fnw + (fj - funcbufptr) + delta, fj, first_free - fj);
+			for (k = j; k < MAX_NR_FUNC; k++)
+			  if (func_table[k])
+			    func_table[k] = fnw + (func_table[k] - funcbufptr) + delta;
+		    }
+		    if (funcbufptr != func_buf)
+		      kfree(funcbufptr);
+		    funcbufptr = fnw;
+		    funcbufleft = funcbufleft - delta + sz - funcbufsize;
+		    funcbufsize = sz;
+		}
+		strcpy(func_table[i], kbs->kb_string);
+		break;
+	}
+	ret = 0;
+reterr:
+	kfree(kbs);
+	return ret;
+}
+
+static inline int 
+do_fontx_ioctl(int cmd, struct consolefontdesc __user *user_cfd, int perm, struct console_font_op *op)
+{
+	struct consolefontdesc cfdarg;
+	int i;
+
+	if (copy_from_user(&cfdarg, user_cfd, sizeof(struct consolefontdesc))) 
+		return -EFAULT;
+ 	
+	switch (cmd) {
+	case PIO_FONTX:
+		if (!perm)
+			return -EPERM;
+		op->op = KD_FONT_OP_SET;
+		op->flags = KD_FONT_FLAG_OLD;
+		op->width = 8;
+		op->height = cfdarg.charheight;
+		op->charcount = cfdarg.charcount;
+		op->data = cfdarg.chardata;
+		return con_font_op(vc_cons[fg_console].d, op);
+	case GIO_FONTX: {
+		op->op = KD_FONT_OP_GET;
+		op->flags = KD_FONT_FLAG_OLD;
+		op->width = 8;
+		op->height = cfdarg.charheight;
+		op->charcount = cfdarg.charcount;
+		op->data = cfdarg.chardata;
+		i = con_font_op(vc_cons[fg_console].d, op);
+		if (i)
+			return i;
+		cfdarg.charheight = op->height;
+		cfdarg.charcount = op->charcount;
+		if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc)))
+			return -EFAULT;
+		return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static inline int 
+do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud, int perm, struct vc_data *vc)
+{
+	struct unimapdesc tmp;
+
+	if (copy_from_user(&tmp, user_ud, sizeof tmp))
+		return -EFAULT;
+	if (tmp.entries)
+		if (!access_ok(VERIFY_WRITE, tmp.entries,
+				tmp.entry_ct*sizeof(struct unipair)))
+			return -EFAULT;
+	switch (cmd) {
+	case PIO_UNIMAP:
+		if (!perm)
+			return -EPERM;
+		return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
+	case GIO_UNIMAP:
+		if (!perm && fg_console != vc->vc_num)
+			return -EPERM;
+		return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp.entries);
+	}
+	return 0;
+}
+
+/*
+ * We handle the console-specific ioctl's here.  We allow the
+ * capability to modify any console, not just the fg_console. 
+ */
+int vt_ioctl(struct tty_struct *tty, struct file * file,
+	     unsigned int cmd, unsigned long arg)
+{
+	struct vc_data *vc = (struct vc_data *)tty->driver_data;
+	struct console_font_op op;	/* used in multiple places here */
+	struct kbd_struct * kbd;
+	unsigned int console;
+	unsigned char ucval;
+	void __user *up = (void __user *)arg;
+	int i, perm;
+	
+	console = vc->vc_num;
+
+	if (!vc_cons_allocated(console)) 	/* impossible? */
+		return -ENOIOCTLCMD;
+
+	/*
+	 * To have permissions to do most of the vt ioctls, we either have
+	 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
+	 */
+	perm = 0;
+	if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
+		perm = 1;
+ 
+	kbd = kbd_table + console;
+	switch (cmd) {
+	case KIOCSOUND:
+		if (!perm)
+			return -EPERM;
+		if (arg)
+			arg = 1193182 / 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 = 1193182 / count;
+		kd_mksound(count, ticks);
+		return 0;
+	}
+
+	case KDGKBTYPE:
+		/*
+		 * this is naive.
+		 */
+		ucval = KB_101;
+		goto setchar;
+
+		/*
+		 * These cannot be implemented on any machine that implements
+		 * ioperm() in user level (such as Alpha PCs) or not at all.
+		 *
+		 * XXX: you should never use these, just call ioperm directly..
+		 */
+#ifdef CONFIG_X86
+	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
+
+	/* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
+		
+	case KDKBDREP:
+	{
+		struct kbd_repeat kbrep;
+		int err;
+		
+		if (!capable(CAP_SYS_TTY_CONFIG))
+			return -EPERM;
+
+		if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat)))
+			return -EFAULT;
+		err = kbd_rate(&kbrep);
+		if (err)
+			return err;
+		if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
+			return -EFAULT;
+		return 0;
+	}
+
+	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...
+		 *
+		 * XXX It should at least call into the driver, fbdev's definitely
+		 * need to restore their engine state. --BenH
+		 */
+		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 (vc->vc_mode == (unsigned char) arg)
+			return 0;
+		vc->vc_mode = (unsigned char) arg;
+		if (console != fg_console)
+			return 0;
+		/*
+		 * explicitly blank/unblank the screen if switching modes
+		 */
+		acquire_console_sem();
+		if (arg == KD_TEXT)
+			do_unblank_screen(1);
+		else
+			do_blank_screen(1);
+		release_console_sem();
+		return 0;
+
+	case KDGETMODE:
+		ucval = vc->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;
+		}
+		tty_ldisc_flush(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 __user *)arg); 
+
+	case KDGETKEYCODE:
+	case KDSETKEYCODE:
+		if(!capable(CAP_SYS_TTY_CONFIG))
+			perm=0;
+		return do_kbkeycode_ioctl(cmd, up, perm);
+
+	case KDGKBENT:
+	case KDSKBENT:
+		return do_kdsk_ioctl(cmd, up, perm, kbd);
+
+	case KDGKBSENT:
+	case KDSKBSENT:
+		return do_kdgkb_ioctl(cmd, up, perm);
+
+	case KDGKBDIACR:
+	{
+		struct kbdiacrs __user *a = up;
+
+		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 __user *a = up;
+		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 __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();
+		vc->vt_mode = tmp;
+		/* the frsig is ignored, so we set it to 0 */
+		vc->vt_mode.frsig = 0;
+		vc->vt_pid = current->pid;
+		/* no switch is required -- saw@shade.msu.ru */
+		vc->vt_newvt = -1;
+		release_console_sem();
+		return 0;
+	}
+
+	case VT_GETMODE:
+	{
+		struct vt_mode tmp;
+		int rc;
+
+		acquire_console_sem();
+		memcpy(&tmp, &vc->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 (vc->vt_mode.mode != VT_PROCESS)
+			return -EINVAL;
+
+		/*
+		 * Switching-from response
+		 */
+		if (vc->vt_newvt >= 0) {
+			if (arg == 0)
+				/*
+				 * Switch disallowed, so forget we were trying
+				 * to do it.
+				 */
+				vc->vt_newvt = -1;
+
+			else {
+				/*
+				 * The current vt has been released, so
+				 * complete the switch.
+				 */
+				int newvt;
+				acquire_console_sem();
+				newvt = vc->vt_newvt;
+				vc->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(vc_cons[newvt].d);
+				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(vc_cons[i].d, 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 (!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_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;
+	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(struct vc_data *vc)
+{
+	vc->vc_mode = KD_TEXT;
+	kbd_table[vc->vc_num].kbdmode = 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;
+	vc->vt_pid = -1;
+	vc->vt_newvt = -1;
+	if (!in_interrupt())    /* Via keyboard.c:SAK() - akpm */
+		reset_palette(vc);
+}
+
+/*
+ * 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_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 != 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_proc() will
+		 * tell us if the process has gone or something else
+		 * is awry
+		 */
+		if (kill_proc(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_proc() will
+		 * tell us if the process has gone or something else
+		 * is awry
+		 */
+		if (kill_proc(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.
+			 */
+			vc->vt_newvt = new_vc->vc_num;
+			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);
+}