vt_ioctl.c

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/*
 *  linux/drivers/char/vt_ioctl.c
 *
 *  Copyright (C) 1992 obz under the linux copyright
 *
 *  Dynamic diacritical handling - [e-mail] - Dec 1993
 *  Dynamic keymap and string allocation - [e-mail] - May 1994
 *  Restrict VT switching via ioctl() - [e-mail] - Dec 1995
 *  Some code moved for less code duplication - Andi Kleen - Mar 1997
 *  Check put/get_user, cleanups - [e-mail] - 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