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vt_ioctl.c

/*
 *  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/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 <linux/consolemap.h>
#include <linux/signal.h>
#include <linux/timex.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>

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;

      if (!capable(CAP_SYS_TTY_CONFIG))
            perm = 0;

      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) {
                  /* deallocate 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 = 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;

      if (!capable(CAP_SYS_TTY_CONFIG))
            perm = 0;

      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 = 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 = CLOCK_TICK_RATE / 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 = CLOCK_TICK_RATE / 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;
            struct kbdiacr diacr;
            int i;

            if (put_user(accent_table_size, &a->kb_cnt))
                  return -EFAULT;
            for (i = 0; i < accent_table_size; i++) {
                  diacr.diacr = conv_uni_to_8bit(accent_table[i].diacr);
                  diacr.base = conv_uni_to_8bit(accent_table[i].base);
                  diacr.result = conv_uni_to_8bit(accent_table[i].result);
                  if (copy_to_user(a->kbdiacr + i, &diacr, sizeof(struct kbdiacr)))
                        return -EFAULT;
            }
            return 0;
      }
      case KDGKBDIACRUC:
      {
            struct kbdiacrsuc __user *a = up;

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

      case KDSKBDIACR:
      {
            struct kbdiacrs __user *a = up;
            struct kbdiacr diacr;
            unsigned int ct;
            int i;

            if (!perm)
                  return -EPERM;
            if (get_user(ct,&a->kb_cnt))
                  return -EFAULT;
            if (ct >= MAX_DIACR)
                  return -EINVAL;
            accent_table_size = ct;
            for (i = 0; i < ct; i++) {
                  if (copy_from_user(&diacr, a->kbdiacr + i, sizeof(struct kbdiacr)))
                        return -EFAULT;
                  accent_table[i].diacr = conv_8bit_to_uni(diacr.diacr);
                  accent_table[i].base = conv_8bit_to_uni(diacr.base);
                  accent_table[i].result = conv_8bit_to_uni(diacr.result);
            }
            return 0;
      }

      case KDSKBDIACRUC:
      {
            struct kbdiacrsuc __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->kbdiacruc, ct*sizeof(struct kbdiacruc)))
                  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:
      {
            if (!perm || !capable(CAP_KILL))
              return -EPERM;
            if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
              return -EINVAL;

            spin_lock_irq(&vt_spawn_con.lock);
            put_pid(vt_spawn_con.pid);
            vt_spawn_con.pid = get_pid(task_pid(current));
            vt_spawn_con.sig = arg;
            spin_unlock_irq(&vt_spawn_con.lock);
            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;
            put_pid(vc->vt_pid);
            vc->vt_pid = get_pid(task_pid(current));
            /* 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
             */
            acquire_console_sem();
            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;
                        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);
                  }
            }

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

            return 0;

       /*
        * Disallocate memory associated to VT (but leave VT1)
        */
       case VT_DISALLOCATE:
            if (arg > MAX_NR_CONSOLES)
                  return -ENXIO;
            if (arg == 0) {
                /* deallocate all unused consoles, but leave 0 */
                  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);
}

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