vt_ioctl.c

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/*
 *  Copyright (C) 1992 obz under the linux copyright
 *
 *  Dynamic diacritical handling - [email protected] - Dec 1993
 *  Dynamic keymap and string allocation - [email protected] - May 1994
 *  Restrict VT switching via ioctl() - [email protected] - Dec 1995
 *  Some code moved for less code duplication - Andi Kleen - Mar 1997
 *  Check put/get_user, cleanups - [email protected] - 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/compat.h>
#include <linux/module.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);

/*
 *  User space VT_EVENT handlers
 */

struct vt_event_wait {
    struct list_head list;
    struct vt_event event;
    int done;
};

static LIST_HEAD(vt_events);
static DEFINE_SPINLOCK(vt_event_lock);
static DECLARE_WAIT_QUEUE_HEAD(vt_event_waitqueue);

void vt_event_post(unsigned int event, unsigned int old, unsigned int new)
{
    struct list_head *pos, *head;
    unsigned long flags;
    int wake = 0;

    spin_lock_irqsave(&vt_event_lock, flags);
    head = &vt_events;

    list_for_each(pos, head) {
        struct vt_event_wait *ve = list_entry(pos,
                        struct vt_event_wait, list);
        if (!(ve->event.event & event))
            continue;
        ve->event.event = event;
        /* kernel view is consoles 0..n-1, user space view is
           console 1..n with 0 meaning current, so we must bias */
        ve->event.oldev = old + 1;
        ve->event.newev = new + 1;
        wake = 1;
        ve->done = 1;
    }
    spin_unlock_irqrestore(&vt_event_lock, flags);
    if (wake)
        wake_up_interruptible(&vt_event_waitqueue);
}

static void __vt_event_queue(struct vt_event_wait *vw)
{
    unsigned long flags;
    /* Prepare the event */
    INIT_LIST_HEAD(&vw->list);
    vw->done = 0;
    /* Queue our event */
    spin_lock_irqsave(&vt_event_lock, flags);
    list_add(&vw->list, &vt_events);
    spin_unlock_irqrestore(&vt_event_lock, flags);
}

static void __vt_event_wait(struct vt_event_wait *vw)
{
    /* Wait for it to pass */
    wait_event_interruptible(vt_event_waitqueue, vw->done);
}

static void __vt_event_dequeue(struct vt_event_wait *vw)
{
    unsigned long flags;

    /* Dequeue it */
    spin_lock_irqsave(&vt_event_lock, flags);
    list_del(&vw->list);
    spin_unlock_irqrestore(&vt_event_lock, flags);
}

static void vt_event_wait(struct vt_event_wait *vw)
{
    __vt_event_queue(vw);
    __vt_event_wait(vw);
    __vt_event_dequeue(vw);
}

static int vt_event_wait_ioctl(struct vt_event __user *event)
{
    struct vt_event_wait vw;

    if (copy_from_user(&vw.event, event, sizeof(struct vt_event)))
        return -EFAULT;
    /* Highest supported event for now */
    if (vw.event.event & ~VT_MAX_EVENT)
        return -EINVAL;

    vt_event_wait(&vw);
    /* If it occurred report it */
    if (vw.done) {
        if (copy_to_user(event, &vw.event, sizeof(struct vt_event)))
            return -EFAULT;
        return 0;
    }
    return -EINTR;
}

int vt_waitactive(int n)
{
    struct vt_event_wait vw;
    do {
        vw.event.event = VT_EVENT_SWITCH;
        __vt_event_queue(&vw);
        if (n == fg_console + 1) {
            __vt_event_dequeue(&vw);
            break;
        }
        __vt_event_wait(&vw);
        __vt_event_dequeue(&vw);
        if (vw.done == 0)
            return -EINTR;
    } while (vw.event.newev != n);
    return 0;
}

/*
 * 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)



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,
         unsigned int cmd, unsigned long arg)
{
    struct vc_data *vc = tty->driver_data;
    struct console_font_op op;  /* used in multiple places here */
    unsigned int console;
    unsigned char ucval;
    unsigned int uival;
    void __user *up = (void __user *)arg;
    int i, perm;
    int ret = 0;

    console = vc->vc_num;


    if (!vc_cons_allocated(console)) {  /* impossible? */
        ret = -ENOIOCTLCMD;
        goto out;
    }


    /*
     * 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;
 
    switch (cmd) {
    case TIOCLINUX:
        ret = tioclinux(tty, arg);
        break;
    case KIOCSOUND:
        if (!perm)
            return -EPERM;
        /*
         * The use of PIT_TICK_RATE is historic, it used to be
         * the platform-dependent CLOCK_TICK_RATE between 2.6.12
         * and 2.6.36, which was a minor but unfortunate ABI
         * change. kd_mksound is locked by the input layer.
         */
        if (arg)
            arg = PIT_TICK_RATE / arg;
        kd_mksound(arg, 0);
        break;

    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 = PIT_TICK_RATE / count;
        kd_mksound(count, ticks);
        break;
    }

    case KDGKBTYPE:
        /*
         * this is naïve.
         */
        ucval = KB_101;
        ret = put_user(ucval, (char __user *)arg);
        break;

        /*
         * 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...
         *
         * These are locked internally via sys_ioperm
         */
        if (arg < GPFIRST || arg > GPLAST) {
            ret = -EINVAL;
            break;
        }
        ret = sys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
        break;

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

    /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
        
    case KDKBDREP:
    {
        struct kbd_repeat kbrep;
        
        if (!capable(CAP_SYS_TTY_CONFIG))
            return -EPERM;

        if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat))) {
            ret =  -EFAULT;
            break;
        }
        ret = kbd_rate(&kbrep);
        if (ret)
            break;
        if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
            ret = -EFAULT;
        break;
    }

    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:
            ret = -EINVAL;
            goto out;
        }
        /* FIXME: this needs the console lock extending */
        if (vc->vc_mode == (unsigned char) arg)
            break;
        vc->vc_mode = (unsigned char) arg;
        if (console != fg_console)
            break;
        /*
         * explicitly blank/unblank the screen if switching modes
         */
        console_lock();
        if (arg == KD_TEXT)
            do_unblank_screen(1);
        else
            do_blank_screen(1);
        console_unlock();
        break;

    case KDGETMODE:
        uival = vc->vc_mode;
        goto setint;

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

    case KDSKBMODE:
        if (!perm)
            return -EPERM;
        ret = vt_do_kdskbmode(console, arg);
        if (ret == 0)
            tty_ldisc_flush(tty);
        break;

    case KDGKBMODE:
        uival = vt_do_kdgkbmode(console);
        ret = put_user(uival, (int __user *)arg);
        break;

    /* this could be folded into KDSKBMODE, but for compatibility
       reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
    case KDSKBMETA:
        ret = vt_do_kdskbmeta(console, arg);
        break;

    case KDGKBMETA:
        /* FIXME: should review whether this is worth locking */
        uival = vt_do_kdgkbmeta(console);
    setint:
        ret = put_user(uival, (int __user *)arg);
        break;

    case KDGETKEYCODE:
    case KDSETKEYCODE:
        if(!capable(CAP_SYS_TTY_CONFIG))
            perm = 0;
        ret = vt_do_kbkeycode_ioctl(cmd, up, perm);
        break;

    case KDGKBENT:
    case KDSKBENT:
        ret = vt_do_kdsk_ioctl(cmd, up, perm, console);
        break;

    case KDGKBSENT:
    case KDSKBSENT:
        ret = vt_do_kdgkb_ioctl(cmd, up, perm);
        break;

    /* Diacritical processing. Handled in keyboard.c as it has
       to operate on the keyboard locks and structures */
    case KDGKBDIACR:
    case KDGKBDIACRUC:
    case KDSKBDIACR:
    case KDSKBDIACRUC:
        ret = vt_do_diacrit(cmd, up, perm);
        break;

    /* the ioctls below read/set the flags usually shown in the leds */
    /* don't use them - they will go away without warning */
    case KDGKBLED:
    case KDSKBLED:
    case KDGETLED:
    case KDSETLED:
        ret = vt_do_kdskled(console, cmd, arg, perm);
        break;

    /*
     * 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)
            ret = -EINVAL;
        else {
            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);
        }
        break;
    }

    case VT_SETMODE:
    {
        struct vt_mode tmp;

        if (!perm)
            return -EPERM;
        if (copy_from_user(&tmp, up, sizeof(struct vt_mode))) {
            ret = -EFAULT;
            goto out;
        }
        if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS) {
            ret = -EINVAL;
            goto out;
        }
        console_lock();
        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 -- [email protected] */
        vc->vt_newvt = -1;
        console_unlock();
        break;
    }

    case VT_GETMODE:
    {
        struct vt_mode tmp;
        int rc;

        console_lock();
        memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
        console_unlock();

        rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
        if (rc)
            ret = -EFAULT;
        break;
    }

    /*
     * 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;

        /* Review: FIXME: Console lock ? */
        if (put_user(fg_console + 1, &vtstat->v_active))
            ret = -EFAULT;
        else {
            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;
            ret = put_user(state, &vtstat->v_state);
        }
        break;
    }

    /*
     * Returns the first available (non-opened) console.
     */
    case VT_OPENQRY:
        /* FIXME: locking ? - but then this is a stupid API */
        for (i = 0; i < MAX_NR_CONSOLES; ++i)
            if (! VT_IS_IN_USE(i))
                break;
        uival = 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)
            ret =  -ENXIO;
        else {
            arg--;
            console_lock();
            ret = vc_allocate(arg);
            console_unlock();
            if (ret)
                break;
            set_console(arg);
        }
        break;

    case VT_SETACTIVATE:
    {
        struct vt_setactivate vsa;

        if (!perm)
            return -EPERM;

        if (copy_from_user(&vsa, (struct vt_setactivate __user *)arg,
                    sizeof(struct vt_setactivate))) {
            ret = -EFAULT;
            goto out;
        }
        if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
            ret = -ENXIO;
        else {
            vsa.console--;
            console_lock();
            ret = vc_allocate(vsa.console);
            if (ret == 0) {
                struct vc_data *nvc;
                /* This is safe providing we don't drop the
                   console sem between vc_allocate and
                   finishing referencing nvc */
                nvc = vc_cons[vsa.console].d;
                nvc->vt_mode = vsa.mode;
                nvc->vt_mode.frsig = 0;
                put_pid(nvc->vt_pid);
                nvc->vt_pid = get_pid(task_pid(current));
            }
            console_unlock();
            if (ret)
                break;
            /* Commence switch and lock */
            /* Review set_console locks */
            set_console(vsa.console);
        }
        break;
    }

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

    /*
     * 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;

        console_lock();
        if (vc->vt_mode.mode != VT_PROCESS) {
            console_unlock();
            ret = -EINVAL;
            break;
        }
        /*
         * 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;
                newvt = vc->vt_newvt;
                vc->vt_newvt = -1;
                ret = vc_allocate(newvt);
                if (ret) {
                    console_unlock();
                    break;
                }
                /*
                 * 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);
            }
        } else {
            /*
             * Switched-to response
             */
            /*
             * If it's just an ACK, ignore it
             */
            if (arg != VT_ACKACQ)
                ret = -EINVAL;
        }
        console_unlock();
        break;

     /*
      * Disallocate memory associated to VT (but leave VT1)
      */
     case VT_DISALLOCATE:
        if (arg > MAX_NR_CONSOLES) {
            ret = -ENXIO;
            break;
        }
        if (arg == 0) {
            /* deallocate all unused consoles, but leave 0 */
            console_lock();
            for (i=1; i<MAX_NR_CONSOLES; i++)
                if (! VT_BUSY(i))
                    vc_deallocate(i);
            console_unlock();
        } else {
            /* deallocate a single console, if possible */
            arg--;
            if (VT_BUSY(arg))
                ret = -EBUSY;
            else if (arg) {               /* leave 0 */
                console_lock();
                vc_deallocate(arg);
                console_unlock();
            }
        }
        break;

    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))
            ret = -EFAULT;
        else {
            console_lock();
            for (i = 0; i < MAX_NR_CONSOLES; i++) {
                vc = vc_cons[i].d;

                if (vc) {
                    vc->vc_resize_user = 1;
                    /* FIXME: review v tty lock */
                    vc_resize(vc_cons[i].d, cc, ll);
                }
            }
            console_unlock();
        }
        break;
    }

    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))) {
            ret = -EFAULT;
            break;
        }
        /* FIXME: Should check the copies properly */
        __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) {
                    /* Parameters don't add up */
                    ret = -EINVAL;
                    break;
                }
            } else 
                ll = vlin/clin;
        }
        if (vcol && ccol) {
            if (cc) {
                if (cc != vcol/ccol) {
                    ret = -EINVAL;
                    break;
                }
            } else
                cc = vcol/ccol;
        }

        if (clin > 32) {
            ret =  -EINVAL;
            break;
        }
            
        for (i = 0; i < MAX_NR_CONSOLES; i++) {
            if (!vc_cons[i].d)
                continue;
            console_lock();
            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);
            console_unlock();
        }
        break;
    }

    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;
        ret = con_font_op(vc_cons[fg_console].d, &op);
        break;
    }

    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;
        ret = con_font_op(vc_cons[fg_console].d, &op);
        break;
    }

    case PIO_CMAP:
                if (!perm)
            ret = -EPERM;
        else
                    ret = con_set_cmap(up);
        break;

    case GIO_CMAP:
                ret = con_get_cmap(up);
        break;

    case PIO_FONTX:
    case GIO_FONTX:
        ret = do_fontx_ioctl(cmd, up, perm, &op);
        break;

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

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

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

    case PIO_SCRNMAP:
        if (!perm)
            ret = -EPERM;
        else
            ret = con_set_trans_old(up);
        break;

    case GIO_SCRNMAP:
        ret = con_get_trans_old(up);
        break;

    case PIO_UNISCRNMAP:
        if (!perm)
            ret = -EPERM;
        else
            ret = con_set_trans_new(up);
        break;

    case GIO_UNISCRNMAP:
        ret = con_get_trans_new(up);
        break;

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

    case PIO_UNIMAP:
    case GIO_UNIMAP:
        ret = do_unimap_ioctl(cmd, up, perm, vc);
        break;

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

void reset_vc(struct vc_data *vc)
{
    vc->vc_mode = KD_TEXT;
    vt_reset_unicode(vc->vc_num);
    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;

    console_lock();
    vc = vc_con->d;
    if (vc) {
        /* FIXME: review tty ref counting */
        tty = vc->port.tty;
        /*
         * SAK should also work in all raw modes and reset
         * them properly.
         */
        if (tty)
            __do_SAK(tty);
        reset_vc(vc);
    }
    console_unlock();
}

#ifdef CONFIG_COMPAT

struct compat_consolefontdesc {
    unsigned short charcount;       /* characters in font (256 or 512) */
    unsigned short charheight;      /* scan lines per character (1-32) */
    compat_caddr_t chardata;    /* font data in expanded form */
};

static inline int
compat_fontx_ioctl(int cmd, struct compat_consolefontdesc __user *user_cfd,
             int perm, struct console_font_op *op)
{
    struct compat_consolefontdesc cfdarg;
    int i;

    if (copy_from_user(&cfdarg, user_cfd, sizeof(struct compat_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 = compat_ptr(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 = compat_ptr(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 compat_consolefontdesc)))
            return -EFAULT;
        return 0;
    }
    return -EINVAL;
}

struct compat_console_font_op {
    compat_uint_t op;        /* operation code KD_FONT_OP_* */
    compat_uint_t flags;     /* KD_FONT_FLAG_* */
    compat_uint_t width, height;     /* font size */
    compat_uint_t charcount;
    compat_caddr_t data;    /* font data with height fixed to 32 */
};

static inline int
compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop,
             int perm, struct console_font_op *op, struct vc_data *vc)
{
    int i;

    if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op)))
        return -EFAULT;
    if (!perm && op->op != KD_FONT_OP_GET)
        return -EPERM;
    op->data = compat_ptr(((struct compat_console_font_op *)op)->data);
    i = con_font_op(vc, op);
    if (i)
        return i;
    ((struct compat_console_font_op *)op)->data = (unsigned long)op->data;
    if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op)))
        return -EFAULT;
    return 0;
}

struct compat_unimapdesc {
    unsigned short entry_ct;
    compat_caddr_t entries;
};

static inline int
compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud,
             int perm, struct vc_data *vc)
{
    struct compat_unimapdesc tmp;
    struct unipair __user *tmp_entries;

    if (copy_from_user(&tmp, user_ud, sizeof tmp))
        return -EFAULT;
    tmp_entries = compat_ptr(tmp.entries);
    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;
}

long vt_compat_ioctl(struct tty_struct *tty,
         unsigned int cmd, unsigned long arg)
{
    struct vc_data *vc = tty->driver_data;
    struct console_font_op op;  /* used in multiple places here */
    unsigned int console;
    void __user *up = (void __user *)arg;
    int perm;
    int ret = 0;

    console = vc->vc_num;

    if (!vc_cons_allocated(console)) {  /* impossible? */
        ret = -ENOIOCTLCMD;
        goto out;
    }

    /*
     * 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;

    switch (cmd) {
    /*
     * these need special handlers for incompatible data structures
     */
    case PIO_FONTX:
    case GIO_FONTX:
        ret = compat_fontx_ioctl(cmd, up, perm, &op);
        break;

    case KDFONTOP:
        ret = compat_kdfontop_ioctl(up, perm, &op, vc);
        break;

    case PIO_UNIMAP:
    case GIO_UNIMAP:
        ret = compat_unimap_ioctl(cmd, up, perm, vc);
        break;

    /*
     * all these treat 'arg' as an integer
     */
    case KIOCSOUND:
    case KDMKTONE:
#ifdef CONFIG_X86
    case KDADDIO:
    case KDDELIO:
#endif
    case KDSETMODE:
    case KDMAPDISP:
    case KDUNMAPDISP:
    case KDSKBMODE:
    case KDSKBMETA:
    case KDSKBLED:
    case KDSETLED:
    case KDSIGACCEPT:
    case VT_ACTIVATE:
    case VT_WAITACTIVE:
    case VT_RELDISP:
    case VT_DISALLOCATE:
    case VT_RESIZE:
    case VT_RESIZEX:
        goto fallback;

    /*
     * the rest has a compatible data structure behind arg,
     * but we have to convert it to a proper 64 bit pointer.
     */
    default:
        arg = (unsigned long)compat_ptr(arg);
        goto fallback;
    }
out:
    return ret;

fallback:
    return vt_ioctl(tty, cmd, arg);
}


#endif /* CONFIG_COMPAT */


/*
 * Performs the back end of a vt switch. Called under the console
 * semaphore.
 */
static void complete_change_console(struct vc_data *vc)
{
    unsigned char old_vc_mode;
    int old = fg_console;

    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_event_post(VT_EVENT_SWITCH, old, vc->vc_num);
    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);
}

/* Perform a kernel triggered VT switch for suspend/resume */

static int disable_vt_switch;

int vt_move_to_console(unsigned int vt, int alloc)
{
    int prev;

    console_lock();
    /* Graphics mode - up to X */
    if (disable_vt_switch) {
        console_unlock();
        return 0;
    }
    prev = fg_console;

    if (alloc && vc_allocate(vt)) {
        /* we can't have a free VC for now. Too bad,
         * we don't want to mess the screen for now. */
        console_unlock();
        return -ENOSPC;
    }

    if (set_console(vt)) {
        /*
         * We're unable to switch to the SUSPEND_CONSOLE.
         * Let the calling function know so it can decide
         * what to do.
         */
        console_unlock();
        return -EIO;
    }
    console_unlock();
    if (vt_waitactive(vt + 1)) {
        pr_debug("Suspend: Can't switch VCs.");
        return -EINTR;
    }
    return prev;
}

/*
 * Normally during a suspend, we allocate a new console and switch to it.
 * When we resume, we switch back to the original console.  This switch
 * can be slow, so on systems where the framebuffer can handle restoration
 * of video registers anyways, there's little point in doing the console
 * switch.  This function allows you to disable it by passing it '0'.
 */
void pm_set_vt_switch(int do_switch)
{
    console_lock();
    disable_vt_switch = !do_switch;
    console_unlock();
}
EXPORT_SYMBOL(pm_set_vt_switch);