drivers/tty/vt/selection.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * This module exports the functions:
  *
  *     'int set_selection_user(struct tiocl_selection __user *,
  *			       struct tty_struct *)'
  *     'int set_selection_kernel(struct tiocl_selection *, struct tty_struct *)'
  *     'void clear_selection(void)'
  *     'int paste_selection(struct tty_struct *)'
  *     'int sel_loadlut(u32 __user *)'
  *
  * Now that /dev/vcs exists, most of this can disappear again.
  */

 #include <linux/module.h>
 #include <linux/tty.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/types.h>

 #include <linux/uaccess.h>

 #include <linux/kbd_kern.h>
 #include <linux/vt_kern.h>
 #include <linux/consolemap.h>
 #include <linux/selection.h>
 #include <linux/tiocl.h>
 #include <linux/console.h>
 #include <linux/tty_flip.h>

 #include <linux/sched/signal.h>

 /* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
 #define is_space_on_vt(c)	((c) == ' ')

 /* FIXME: all this needs locking */
 static struct vc_selection {
 	struct mutex lock;
 	struct vc_data *cons;			/* must not be deallocated */
 	char *buffer;
 	unsigned int buf_len;
 	volatile int start;			/* cleared by clear_selection */
 	int end;
 } vc_sel = {
 	.lock = __MUTEX_INITIALIZER(vc_sel.lock),
 	.start = -1,
 };

 /* clear_selection, highlight and highlight_pointer can be called
    from interrupt (via scrollback/front) */

 /* set reverse video on characters s-e of console with selection. */
 static inline void highlight(const int s, const int e)
 {
 	invert_screen(vc_sel.cons, s, e-s+2, true);
 }

 /* use complementary color to show the pointer */
 static inline void highlight_pointer(const int where)
 {
 	complement_pos(vc_sel.cons, where);
 }

 static u32
 sel_pos(int n, bool unicode)
 {
 	if (unicode)
 		return screen_glyph_unicode(vc_sel.cons, n / 2);
 	return inverse_translate(vc_sel.cons, screen_glyph(vc_sel.cons, n),
 			false);
 }

 /**
  * clear_selection - remove current selection
  *
  * Remove the current selection highlight, if any from the console holding the
  * selection.
  *
  * Locking: The caller must hold the console lock.
  */
 void clear_selection(void)
 {
 	highlight_pointer(-1); /* hide the pointer */
 	if (vc_sel.start != -1) {
 		highlight(vc_sel.start, vc_sel.end);
 		vc_sel.start = -1;
 	}
 }
 EXPORT_SYMBOL_GPL(clear_selection);

 bool vc_is_sel(const struct vc_data *vc)
 {
 	return vc == vc_sel.cons;
 }

 /*
  * User settable table: what characters are to be considered alphabetic?
  * 128 bits. Locked by the console lock.
  */
 static u32 inwordLut[]={
   0x00000000, /* control chars     */
   0x03FFE000, /* digits and "-./"  */
   0x87FFFFFE, /* uppercase and '_' */
   0x07FFFFFE, /* lowercase         */
 };

 static inline int inword(const u32 c)
 {
 	return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
 }

 /**
  * sel_loadlut() - load the LUT table
  * @lut: user table
  *
  * Load the LUT table from user space. Make a temporary copy so a partial
  * update doesn't make a mess.
  *
  * Locking: The console lock is acquired.
  */
 int sel_loadlut(u32 __user *lut)
 {
 	u32 tmplut[ARRAY_SIZE(inwordLut)];

 	if (copy_from_user(tmplut, lut, sizeof(inwordLut)))
 		return -EFAULT;

 	console_lock();
 	memcpy(inwordLut, tmplut, sizeof(inwordLut));
 	console_unlock();

 	return 0;
 }

 /* does screen address p correspond to character at LH/RH edge of screen? */
 static inline int atedge(const int p, int size_row)
 {
 	return (!(p % size_row)	|| !((p + 2) % size_row));
 }

 /* stores the char in UTF8 and returns the number of bytes used (1-4) */
 static int store_utf8(u32 c, char *p)
 {
 	if (c < 0x80) {
 		/*  0******* */
 		p[0] = c;
 		return 1;
 	} else if (c < 0x800) {
 		/* 110***** 10****** */
 		p[0] = 0xc0 | (c >> 6);
 		p[1] = 0x80 | (c & 0x3f);
 		return 2;
 	} else if (c < 0x10000) {
 		/* 1110**** 10****** 10****** */
 		p[0] = 0xe0 | (c >> 12);
 		p[1] = 0x80 | ((c >> 6) & 0x3f);
 		p[2] = 0x80 | (c & 0x3f);
 		return 3;
 	} else if (c < 0x110000) {
 		/* 11110*** 10****** 10****** 10****** */
 		p[0] = 0xf0 | (c >> 18);
 		p[1] = 0x80 | ((c >> 12) & 0x3f);
 		p[2] = 0x80 | ((c >> 6) & 0x3f);
 		p[3] = 0x80 | (c & 0x3f);
 		return 4;
 	} else {
 		/* outside Unicode, replace with U+FFFD */
 		p[0] = 0xef;
 		p[1] = 0xbf;
 		p[2] = 0xbd;
 		return 3;
 	}
 }

 /**
  * set_selection_user - set the current selection.
  * @sel: user selection info
  * @tty: the console tty
  *
  * Invoked by the ioctl handle for the vt layer.
  *
  * Locking: The entire selection process is managed under the console_lock.
  * It's a lot under the lock but its hardly a performance path.
  */
 int set_selection_user(const struct tiocl_selection __user *sel,
 		       struct tty_struct *tty)
 {
 	struct tiocl_selection v;

 	if (copy_from_user(&v, sel, sizeof(*sel)))
 		return -EFAULT;

 	return set_selection_kernel(&v, tty);
 }

 static int vc_selection_store_chars(struct vc_data *vc, bool unicode)
 {
 	char *bp, *obp;
 	unsigned int i;

 	/* Allocate a new buffer before freeing the old one ... */
 	/* chars can take up to 4 bytes with unicode */
 	bp = kmalloc_array((vc_sel.end - vc_sel.start) / 2 + 1, unicode ? 4 : 1,
 			   GFP_KERNEL | __GFP_NOWARN);
 	if (!bp) {
 		printk(KERN_WARNING "selection: kmalloc() failed\n");
 		clear_selection();
 		return -ENOMEM;
 	}
 	kfree(vc_sel.buffer);
 	vc_sel.buffer = bp;

 	obp = bp;
 	for (i = vc_sel.start; i <= vc_sel.end; i += 2) {
 		u32 c = sel_pos(i, unicode);
 		if (unicode)
 			bp += store_utf8(c, bp);
 		else
 			*bp++ = c;
 		if (!is_space_on_vt(c))
 			obp = bp;
 		if (!((i + 2) % vc->vc_size_row)) {
 			/* strip trailing blanks from line and add newline,
 			   unless non-space at end of line. */
 			if (obp != bp) {
 				bp = obp;
 				*bp++ = '\r';
 			}
 			obp = bp;
 		}
 	}
 	vc_sel.buf_len = bp - vc_sel.buffer;

 	return 0;
 }

 static int vc_do_selection(struct vc_data *vc, unsigned short mode, int ps,
 		int pe)
 {
 	int new_sel_start, new_sel_end, spc;
 	bool unicode = vt_do_kdgkbmode(fg_console) == K_UNICODE;

 	switch (mode) {
 	case TIOCL_SELCHAR:	/* character-by-character selection */
 		new_sel_start = ps;
 		new_sel_end = pe;
 		break;
 	case TIOCL_SELWORD:	/* word-by-word selection */
 		spc = is_space_on_vt(sel_pos(ps, unicode));
 		for (new_sel_start = ps; ; ps -= 2) {
 			if ((spc && !is_space_on_vt(sel_pos(ps, unicode))) ||
 			    (!spc && !inword(sel_pos(ps, unicode))))
 				break;
 			new_sel_start = ps;
 			if (!(ps % vc->vc_size_row))
 				break;
 		}

 		spc = is_space_on_vt(sel_pos(pe, unicode));
 		for (new_sel_end = pe; ; pe += 2) {
 			if ((spc && !is_space_on_vt(sel_pos(pe, unicode))) ||
 			    (!spc && !inword(sel_pos(pe, unicode))))
 				break;
 			new_sel_end = pe;
 			if (!((pe + 2) % vc->vc_size_row))
 				break;
 		}
 		break;
 	case TIOCL_SELLINE:	/* line-by-line selection */
 		new_sel_start = rounddown(ps, vc->vc_size_row);
 		new_sel_end = rounddown(pe, vc->vc_size_row) +
 			vc->vc_size_row - 2;
 		break;
 	case TIOCL_SELPOINTER:
 		highlight_pointer(pe);
 		return 0;
 	default:
 		return -EINVAL;
 	}

 	/* remove the pointer */
 	highlight_pointer(-1);

 	/* select to end of line if on trailing space */
 	if (new_sel_end > new_sel_start &&
 		!atedge(new_sel_end, vc->vc_size_row) &&
 		is_space_on_vt(sel_pos(new_sel_end, unicode))) {
 		for (pe = new_sel_end + 2; ; pe += 2)
 			if (!is_space_on_vt(sel_pos(pe, unicode)) ||
 			    atedge(pe, vc->vc_size_row))
 				break;
 		if (is_space_on_vt(sel_pos(pe, unicode)))
 			new_sel_end = pe;
 	}
 	if (vc_sel.start == -1)	/* no current selection */
 		highlight(new_sel_start, new_sel_end);
 	else if (new_sel_start == vc_sel.start)
 	{
 		if (new_sel_end == vc_sel.end)	/* no action required */
 			return 0;
 		else if (new_sel_end > vc_sel.end)	/* extend to right */
 			highlight(vc_sel.end + 2, new_sel_end);
 		else				/* contract from right */
 			highlight(new_sel_end + 2, vc_sel.end);
 	}
 	else if (new_sel_end == vc_sel.end)
 	{
 		if (new_sel_start < vc_sel.start) /* extend to left */
 			highlight(new_sel_start, vc_sel.start - 2);
 		else				/* contract from left */
 			highlight(vc_sel.start, new_sel_start - 2);
 	}
 	else	/* some other case; start selection from scratch */
 	{
 		clear_selection();
 		highlight(new_sel_start, new_sel_end);
 	}
 	vc_sel.start = new_sel_start;
 	vc_sel.end = new_sel_end;

 	return vc_selection_store_chars(vc, unicode);
 }

 static int vc_selection(struct vc_data *vc, struct tiocl_selection *v,
 		struct tty_struct *tty)
 {
 	int ps, pe;

 	poke_blanked_console();

 	if (v->sel_mode == TIOCL_SELCLEAR) {
 		/* useful for screendump without selection highlights */
 		clear_selection();
 		return 0;
 	}

 	v->xs = min_t(u16, v->xs - 1, vc->vc_cols - 1);
 	v->ys = min_t(u16, v->ys - 1, vc->vc_rows - 1);
 	v->xe = min_t(u16, v->xe - 1, vc->vc_cols - 1);
 	v->ye = min_t(u16, v->ye - 1, vc->vc_rows - 1);

 	if (mouse_reporting() && (v->sel_mode & TIOCL_SELMOUSEREPORT)) {
 		mouse_report(tty, v->sel_mode & TIOCL_SELBUTTONMASK, v->xs,
 			     v->ys);
 		return 0;
 	}

 	ps = v->ys * vc->vc_size_row + (v->xs << 1);
 	pe = v->ye * vc->vc_size_row + (v->xe << 1);
 	if (ps > pe)	/* make vc_sel.start <= vc_sel.end */
 		swap(ps, pe);

 	if (vc_sel.cons != vc) {
 		clear_selection();
 		vc_sel.cons = vc;
 	}

 	return vc_do_selection(vc, v->sel_mode, ps, pe);
 }

 int set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
 {
 	int ret;

 	mutex_lock(&vc_sel.lock);
 	console_lock();
 	ret = vc_selection(vc_cons[fg_console].d, v, tty);
 	console_unlock();
 	mutex_unlock(&vc_sel.lock);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(set_selection_kernel);

 /* Insert the contents of the selection buffer into the
  * queue of the tty associated with the current console.
  * Invoked by ioctl().
  *
  * Locking: called without locks. Calls the ldisc wrongly with
  * unsafe methods,
  */
 int paste_selection(struct tty_struct *tty)
 {
 	struct vc_data *vc = tty->driver_data;
 	int	pasted = 0;
 	size_t count;
 	struct  tty_ldisc *ld;
 	DECLARE_WAITQUEUE(wait, current);
 	int ret = 0;

 	console_lock();
 	poke_blanked_console();
 	console_unlock();

 	ld = tty_ldisc_ref_wait(tty);
 	if (!ld)
 		return -EIO;	/* ldisc was hung up */
 	tty_buffer_lock_exclusive(&vc->port);

 	add_wait_queue(&vc->paste_wait, &wait);
 	mutex_lock(&vc_sel.lock);
 	while (vc_sel.buffer && vc_sel.buf_len > pasted) {
 		set_current_state(TASK_INTERRUPTIBLE);
 		if (signal_pending(current)) {
 			ret = -EINTR;
 			break;
 		}
 		if (tty_throttled(tty)) {
 			mutex_unlock(&vc_sel.lock);
 			schedule();
 			mutex_lock(&vc_sel.lock);
 			continue;
 		}
 		__set_current_state(TASK_RUNNING);
 		count = vc_sel.buf_len - pasted;
 		count = tty_ldisc_receive_buf(ld, vc_sel.buffer + pasted, NULL,
 					      count);
 		pasted += count;
 	}
 	mutex_unlock(&vc_sel.lock);
 	remove_wait_queue(&vc->paste_wait, &wait);
 	__set_current_state(TASK_RUNNING);

 	tty_buffer_unlock_exclusive(&vc->port);
 	tty_ldisc_deref(ld);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(paste_selection);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* This module exports the functions:
	*
	* 'int set_selection_user(struct tiocl_selection __user *,
	* struct tty_struct *)'
	* 'int set_selection_kernel(struct tiocl_selection , struct tty_struct )'
	* 'void clear_selection(void)'
	* 'int paste_selection(struct tty_struct *)'
	* 'int sel_loadlut(u32 __user *)'
	*
	* Now that /dev/vcs exists, most of this can disappear again.
	*/

	#include <linux/module.h>
	#include <linux/tty.h>
	#include <linux/sched.h>
	#include <linux/mm.h>
	#include <linux/mutex.h>
	#include <linux/slab.h>
	#include <linux/types.h>

	#include <linux/uaccess.h>

	#include <linux/kbd_kern.h>
	#include <linux/vt_kern.h>
	#include <linux/consolemap.h>
	#include <linux/selection.h>
	#include <linux/tiocl.h>
	#include <linux/console.h>
	#include <linux/tty_flip.h>

	#include <linux/sched/signal.h>

	/* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
	#define is_space_on_vt(c) ((c) == ' ')

	/* FIXME: all this needs locking */
	static struct vc_selection {
	struct mutex lock;
	struct vc_data cons; / must not be deallocated */
	char *buffer;
	unsigned int buf_len;
	volatile int start; /* cleared by clear_selection */
	int end;
	} vc_sel = {
	.lock = __MUTEX_INITIALIZER(vc_sel.lock),
	.start = -1,
	};

	/* clear_selection, highlight and highlight_pointer can be called
	from interrupt (via scrollback/front) */

	/* set reverse video on characters s-e of console with selection. */
	static inline void highlight(const int s, const int e)
	{
	invert_screen(vc_sel.cons, s, e-s+2, true);
	}

	/* use complementary color to show the pointer */
	static inline void highlight_pointer(const int where)
	{
	complement_pos(vc_sel.cons, where);
	}

	static u32
	sel_pos(int n, bool unicode)
	{
	if (unicode)
	return screen_glyph_unicode(vc_sel.cons, n / 2);
	return inverse_translate(vc_sel.cons, screen_glyph(vc_sel.cons, n),
	false);
	}

	/**
	* clear_selection - remove current selection
	*
	* Remove the current selection highlight, if any from the console holding the
	* selection.
	*
	* Locking: The caller must hold the console lock.
	*/
	void clear_selection(void)
	{
	highlight_pointer(-1); /* hide the pointer */
	if (vc_sel.start != -1) {
	highlight(vc_sel.start, vc_sel.end);
	vc_sel.start = -1;
	}
	}
	EXPORT_SYMBOL_GPL(clear_selection);

	bool vc_is_sel(const struct vc_data *vc)
	{
	return vc == vc_sel.cons;
	}

	/*
	* User settable table: what characters are to be considered alphabetic?
	* 128 bits. Locked by the console lock.
	*/
	static u32 inwordLut[]={
	0x00000000, /* control chars */
	0x03FFE000, /* digits and "-./" */
	0x87FFFFFE, /* uppercase and '_' */
	0x07FFFFFE, /* lowercase */
	};

	static inline int inword(const u32 c)
	{
	return c > 0x7f \|\| (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
	}

	/**
	* sel_loadlut() - load the LUT table
	* @lut: user table
	*
	* Load the LUT table from user space. Make a temporary copy so a partial
	* update doesn't make a mess.
	*
	* Locking: The console lock is acquired.
	*/
	int sel_loadlut(u32 __user *lut)
	{
	u32 tmplut[ARRAY_SIZE(inwordLut)];

	if (copy_from_user(tmplut, lut, sizeof(inwordLut)))
	return -EFAULT;

	console_lock();
	memcpy(inwordLut, tmplut, sizeof(inwordLut));
	console_unlock();

	return 0;
	}

	/* does screen address p correspond to character at LH/RH edge of screen? */
	static inline int atedge(const int p, int size_row)
	{
	return (!(p % size_row) \|\| !((p + 2) % size_row));
	}

	/* stores the char in UTF8 and returns the number of bytes used (1-4) */
	static int store_utf8(u32 c, char *p)
	{
	if (c < 0x80) {
	/* 0******* */
	p[0] = c;
	return 1;
	} else if (c < 0x800) {
	/* 110*** 10**** */
	p[0] = 0xc0 \| (c >> 6);
	p[1] = 0x80 \| (c & 0x3f);
	return 2;
	} else if (c < 0x10000) {
	/* 1110** 10** 10**** */
	p[0] = 0xe0 \| (c >> 12);
	p[1] = 0x80 \| ((c >> 6) & 0x3f);
	p[2] = 0x80 \| (c & 0x3f);
	return 3;
	} else if (c < 0x110000) {
	/* 11110* 10** 10** 10**** */
	p[0] = 0xf0 \| (c >> 18);
	p[1] = 0x80 \| ((c >> 12) & 0x3f);
	p[2] = 0x80 \| ((c >> 6) & 0x3f);
	p[3] = 0x80 \| (c & 0x3f);
	return 4;
	} else {
	/* outside Unicode, replace with U+FFFD */
	p[0] = 0xef;
	p[1] = 0xbf;
	p[2] = 0xbd;
	return 3;
	}
	}

	/**
	* set_selection_user - set the current selection.
	* @sel: user selection info
	* @tty: the console tty
	*
	* Invoked by the ioctl handle for the vt layer.
	*
	* Locking: The entire selection process is managed under the console_lock.
	* It's a lot under the lock but its hardly a performance path.
	*/
	int set_selection_user(const struct tiocl_selection __user *sel,
	struct tty_struct *tty)
	{
	struct tiocl_selection v;

	if (copy_from_user(&v, sel, sizeof(*sel)))
	return -EFAULT;

	return set_selection_kernel(&v, tty);
	}

	static int vc_selection_store_chars(struct vc_data *vc, bool unicode)
	{
	char bp, obp;
	unsigned int i;

	/* Allocate a new buffer before freeing the old one ... */
	/* chars can take up to 4 bytes with unicode */
	bp = kmalloc_array((vc_sel.end - vc_sel.start) / 2 + 1, unicode ? 4 : 1,
	GFP_KERNEL \| __GFP_NOWARN);
	if (!bp) {
	printk(KERN_WARNING "selection: kmalloc() failed\n");
	clear_selection();
	return -ENOMEM;
	}
	kfree(vc_sel.buffer);
	vc_sel.buffer = bp;

	obp = bp;
	for (i = vc_sel.start; i <= vc_sel.end; i += 2) {
	u32 c = sel_pos(i, unicode);
	if (unicode)
	bp += store_utf8(c, bp);
	else
	*bp++ = c;
	if (!is_space_on_vt(c))
	obp = bp;
	if (!((i + 2) % vc->vc_size_row)) {
	/* strip trailing blanks from line and add newline,
	unless non-space at end of line. */
	if (obp != bp) {
	bp = obp;
	*bp++ = '\r';
	}
	obp = bp;
	}
	}
	vc_sel.buf_len = bp - vc_sel.buffer;

	return 0;
	}

	static int vc_do_selection(struct vc_data *vc, unsigned short mode, int ps,
	int pe)
	{
	int new_sel_start, new_sel_end, spc;
	bool unicode = vt_do_kdgkbmode(fg_console) == K_UNICODE;

	switch (mode) {
	case TIOCL_SELCHAR: /* character-by-character selection */
	new_sel_start = ps;
	new_sel_end = pe;
	break;
	case TIOCL_SELWORD: /* word-by-word selection */
	spc = is_space_on_vt(sel_pos(ps, unicode));
	for (new_sel_start = ps; ; ps -= 2) {
	if ((spc && !is_space_on_vt(sel_pos(ps, unicode))) \|\|
	(!spc && !inword(sel_pos(ps, unicode))))
	break;
	new_sel_start = ps;
	if (!(ps % vc->vc_size_row))
	break;
	}

	spc = is_space_on_vt(sel_pos(pe, unicode));
	for (new_sel_end = pe; ; pe += 2) {
	if ((spc && !is_space_on_vt(sel_pos(pe, unicode))) \|\|
	(!spc && !inword(sel_pos(pe, unicode))))
	break;
	new_sel_end = pe;
	if (!((pe + 2) % vc->vc_size_row))
	break;
	}
	break;
	case TIOCL_SELLINE: /* line-by-line selection */
	new_sel_start = rounddown(ps, vc->vc_size_row);
	new_sel_end = rounddown(pe, vc->vc_size_row) +
	vc->vc_size_row - 2;
	break;
	case TIOCL_SELPOINTER:
	highlight_pointer(pe);
	return 0;
	default:
	return -EINVAL;
	}

	/* remove the pointer */
	highlight_pointer(-1);

	/* select to end of line if on trailing space */
	if (new_sel_end > new_sel_start &&
	!atedge(new_sel_end, vc->vc_size_row) &&
	is_space_on_vt(sel_pos(new_sel_end, unicode))) {
	for (pe = new_sel_end + 2; ; pe += 2)
	if (!is_space_on_vt(sel_pos(pe, unicode)) \|\|
	atedge(pe, vc->vc_size_row))
	break;
	if (is_space_on_vt(sel_pos(pe, unicode)))
	new_sel_end = pe;
	}
	if (vc_sel.start == -1) /* no current selection */
	highlight(new_sel_start, new_sel_end);
	else if (new_sel_start == vc_sel.start)
	{
	if (new_sel_end == vc_sel.end) /* no action required */
	return 0;
	else if (new_sel_end > vc_sel.end) /* extend to right */
	highlight(vc_sel.end + 2, new_sel_end);
	else /* contract from right */
	highlight(new_sel_end + 2, vc_sel.end);
	}
	else if (new_sel_end == vc_sel.end)
	{
	if (new_sel_start < vc_sel.start) /* extend to left */
	highlight(new_sel_start, vc_sel.start - 2);
	else /* contract from left */
	highlight(vc_sel.start, new_sel_start - 2);
	}
	else /* some other case; start selection from scratch */
	{
	clear_selection();
	highlight(new_sel_start, new_sel_end);
	}
	vc_sel.start = new_sel_start;
	vc_sel.end = new_sel_end;

	return vc_selection_store_chars(vc, unicode);
	}

	static int vc_selection(struct vc_data vc, struct tiocl_selection v,
	struct tty_struct *tty)
	{
	int ps, pe;

	poke_blanked_console();

	if (v->sel_mode == TIOCL_SELCLEAR) {
	/* useful for screendump without selection highlights */
	clear_selection();
	return 0;
	}

	v->xs = min_t(u16, v->xs - 1, vc->vc_cols - 1);
	v->ys = min_t(u16, v->ys - 1, vc->vc_rows - 1);
	v->xe = min_t(u16, v->xe - 1, vc->vc_cols - 1);
	v->ye = min_t(u16, v->ye - 1, vc->vc_rows - 1);

	if (mouse_reporting() && (v->sel_mode & TIOCL_SELMOUSEREPORT)) {
	mouse_report(tty, v->sel_mode & TIOCL_SELBUTTONMASK, v->xs,
	v->ys);
	return 0;
	}

	ps = v->ys * vc->vc_size_row + (v->xs << 1);
	pe = v->ye * vc->vc_size_row + (v->xe << 1);
	if (ps > pe) /* make vc_sel.start <= vc_sel.end */
	swap(ps, pe);

	if (vc_sel.cons != vc) {
	clear_selection();
	vc_sel.cons = vc;
	}

	return vc_do_selection(vc, v->sel_mode, ps, pe);
	}

	int set_selection_kernel(struct tiocl_selection v, struct tty_struct tty)
	{
	int ret;

	mutex_lock(&vc_sel.lock);
	console_lock();
	ret = vc_selection(vc_cons[fg_console].d, v, tty);
	console_unlock();
	mutex_unlock(&vc_sel.lock);

	return ret;
	}
	EXPORT_SYMBOL_GPL(set_selection_kernel);

	/* Insert the contents of the selection buffer into the
	* queue of the tty associated with the current console.
	* Invoked by ioctl().
	*
	* Locking: called without locks. Calls the ldisc wrongly with
	* unsafe methods,
	*/
	int paste_selection(struct tty_struct *tty)
	{
	struct vc_data *vc = tty->driver_data;
	int pasted = 0;
	size_t count;
	struct tty_ldisc *ld;
	DECLARE_WAITQUEUE(wait, current);
	int ret = 0;

	console_lock();
	poke_blanked_console();
	console_unlock();

	ld = tty_ldisc_ref_wait(tty);
	if (!ld)
	return -EIO; /* ldisc was hung up */
	tty_buffer_lock_exclusive(&vc->port);

	add_wait_queue(&vc->paste_wait, &wait);
	mutex_lock(&vc_sel.lock);
	while (vc_sel.buffer && vc_sel.buf_len > pasted) {
	set_current_state(TASK_INTERRUPTIBLE);
	if (signal_pending(current)) {
	ret = -EINTR;
	break;
	}
	if (tty_throttled(tty)) {
	mutex_unlock(&vc_sel.lock);
	schedule();
	mutex_lock(&vc_sel.lock);
	continue;
	}
	__set_current_state(TASK_RUNNING);
	count = vc_sel.buf_len - pasted;
	count = tty_ldisc_receive_buf(ld, vc_sel.buffer + pasted, NULL,
	count);
	pasted += count;
	}
	mutex_unlock(&vc_sel.lock);
	remove_wait_queue(&vc->paste_wait, &wait);
	__set_current_state(TASK_RUNNING);

	tty_buffer_unlock_exclusive(&vc->port);
	tty_ldisc_deref(ld);
	return ret;
	}
	EXPORT_SYMBOL_GPL(paste_selection);