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

 // SPDX-License-Identifier: GPL-2.0
 /*
  * This module exports the functions:
  *
  *     'int set_selection(struct tiocl_selection __user *, struct tty_struct *)'
  *     'void clear_selection(void)'
  *     'int paste_selection(struct tty_struct *)'
  *     'int sel_loadlut(char __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/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>

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

 extern void poke_blanked_console(void);

 /* FIXME: all this needs locking */
 /* Variables for selection control. */
 /* Use a dynamic buffer, instead of static (Dec 1994) */
 struct vc_data *sel_cons;		/* must not be deallocated */
 static int use_unicode;
 static volatile int sel_start = -1; 	/* cleared by clear_selection */
 static int sel_end;
 static int sel_buffer_lth;
 static char *sel_buffer;

 /* 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(sel_cons, s, e-s+2, 1);
 }

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

 static u16
 sel_pos(int n)
 {
 	return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
 				use_unicode);
 }

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

 /*
  * 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 u16 c) {
 	return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
 }

 /**
  *	set loadlut		-	load the LUT table
  *	@p: user table
  *
  *	Load the LUT table from user space. The caller must hold the console
  *	lock. Make a temporary copy so a partial update doesn't make a mess.
  */
 int sel_loadlut(char __user *p)
 {
 	u32 tmplut[ARRAY_SIZE(inwordLut)];
 	if (copy_from_user(tmplut, (u32 __user *)(p+4), sizeof(inwordLut)))
 		return -EFAULT;
 	memcpy(inwordLut, tmplut, sizeof(inwordLut));
 	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));
 }

 /* constrain v such that v <= u */
 static inline unsigned short limit(const unsigned short v, const unsigned short u)
 {
 	return (v > u) ? u : v;
 }

 /* stores the char in UTF8 and returns the number of bytes used (1-3) */
 static int store_utf8(u16 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 {
 		/* 1110**** 10****** 10****** */
 		p[0] = 0xe0 | (c >> 12);
 		p[1] = 0x80 | ((c >> 6) & 0x3f);
 		p[2] = 0x80 | (c & 0x3f);
 		return 3;
     	}
 }

 /**
  *	set_selection		- 	set the current selection.
  *	@sel: user selection info
  *	@tty: the console tty
  *
  *	Invoked by the ioctl handle for the vt layer.
  *
  *	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(const struct tiocl_selection __user *sel, struct tty_struct *tty)
 {
 	struct vc_data *vc = vc_cons[fg_console].d;
 	int new_sel_start, new_sel_end, spc;
 	struct tiocl_selection v;
 	char *bp, *obp;
 	int i, ps, pe, multiplier;
 	u16 c;
 	int mode;

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

 	v.xs = limit(v.xs - 1, vc->vc_cols - 1);
 	v.ys = limit(v.ys - 1, vc->vc_rows - 1);
 	v.xe = limit(v.xe - 1, vc->vc_cols - 1);
 	v.ye = limit(v.ye - 1, vc->vc_rows - 1);
 	ps = v.ys * vc->vc_size_row + (v.xs << 1);
 	pe = v.ye * vc->vc_size_row + (v.xe << 1);

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

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

 	if (ps > pe)	/* make sel_start <= sel_end */
 		swap(ps, pe);

 	if (sel_cons != vc_cons[fg_console].d) {
 		clear_selection();
 		sel_cons = vc_cons[fg_console].d;
 	}
 	mode = vt_do_kdgkbmode(fg_console);
 	if (mode == K_UNICODE)
 		use_unicode = 1;
 	else
 		use_unicode = 0;

 	switch (v.sel_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 = isspace(sel_pos(ps));
 			for (new_sel_start = ps; ; ps -= 2)
 			{
 				if ((spc && !isspace(sel_pos(ps))) ||
 				    (!spc && !inword(sel_pos(ps))))
 					break;
 				new_sel_start = ps;
 				if (!(ps % vc->vc_size_row))
 					break;
 			}
 			spc = isspace(sel_pos(pe));
 			for (new_sel_end = pe; ; pe += 2)
 			{
 				if ((spc && !isspace(sel_pos(pe))) ||
 				    (!spc && !inword(sel_pos(pe))))
 					break;
 				new_sel_end = pe;
 				if (!((pe + 2) % vc->vc_size_row))
 					break;
 			}
 			break;
 		case TIOCL_SELLINE:	/* line-by-line selection */
 			new_sel_start = ps - ps % vc->vc_size_row;
 			new_sel_end = pe + vc->vc_size_row
 				    - pe % 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) &&
 		isspace(sel_pos(new_sel_end))) {
 		for (pe = new_sel_end + 2; ; pe += 2)
 			if (!isspace(sel_pos(pe)) ||
 			    atedge(pe, vc->vc_size_row))
 				break;
 		if (isspace(sel_pos(pe)))
 			new_sel_end = pe;
 	}
 	if (sel_start == -1)	/* no current selection */
 		highlight(new_sel_start, new_sel_end);
 	else if (new_sel_start == sel_start)
 	{
 		if (new_sel_end == sel_end)	/* no action required */
 			return 0;
 		else if (new_sel_end > sel_end)	/* extend to right */
 			highlight(sel_end + 2, new_sel_end);
 		else				/* contract from right */
 			highlight(new_sel_end + 2, sel_end);
 	}
 	else if (new_sel_end == sel_end)
 	{
 		if (new_sel_start < sel_start)	/* extend to left */
 			highlight(new_sel_start, sel_start - 2);
 		else				/* contract from left */
 			highlight(sel_start, new_sel_start - 2);
 	}
 	else	/* some other case; start selection from scratch */
 	{
 		clear_selection();
 		highlight(new_sel_start, new_sel_end);
 	}
 	sel_start = new_sel_start;
 	sel_end = new_sel_end;

 	/* Allocate a new buffer before freeing the old one ... */
 	multiplier = use_unicode ? 3 : 1;  /* chars can take up to 3 bytes */
 	bp = kmalloc_array((sel_end - sel_start) / 2 + 1, multiplier,
 			   GFP_KERNEL);
 	if (!bp) {
 		printk(KERN_WARNING "selection: kmalloc() failed\n");
 		clear_selection();
 		return -ENOMEM;
 	}
 	kfree(sel_buffer);
 	sel_buffer = bp;

 	obp = bp;
 	for (i = sel_start; i <= sel_end; i += 2) {
 		c = sel_pos(i);
 		if (use_unicode)
 			bp += store_utf8(c, bp);
 		else
 			*bp++ = c;
 		if (!isspace(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;
 		}
 	}
 	sel_buffer_lth = bp - sel_buffer;
 	return 0;
 }

 /* 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;
 	unsigned int count;
 	struct  tty_ldisc *ld;
 	DECLARE_WAITQUEUE(wait, current);

 	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);
 	while (sel_buffer && sel_buffer_lth > pasted) {
 		set_current_state(TASK_INTERRUPTIBLE);
 		if (tty_throttled(tty)) {
 			schedule();
 			continue;
 		}
 		__set_current_state(TASK_RUNNING);
 		count = sel_buffer_lth - pasted;
 		count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
 					      count);
 		pasted += count;
 	}
 	remove_wait_queue(&vc->paste_wait, &wait);
 	__set_current_state(TASK_RUNNING);

 	tty_buffer_unlock_exclusive(&vc->port);
 	tty_ldisc_deref(ld);
 	return 0;
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* This module exports the functions:
	*
	* 'int set_selection(struct tiocl_selection __user , struct tty_struct )'
	* 'void clear_selection(void)'
	* 'int paste_selection(struct tty_struct *)'
	* 'int sel_loadlut(char __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/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>

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

	extern void poke_blanked_console(void);

	/* FIXME: all this needs locking */
	/* Variables for selection control. */
	/* Use a dynamic buffer, instead of static (Dec 1994) */
	struct vc_data sel_cons; / must not be deallocated */
	static int use_unicode;
	static volatile int sel_start = -1; /* cleared by clear_selection */
	static int sel_end;
	static int sel_buffer_lth;
	static char *sel_buffer;

	/* 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(sel_cons, s, e-s+2, 1);
	}

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

	static u16
	sel_pos(int n)
	{
	return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
	use_unicode);
	}

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

	/*
	* 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 u16 c) {
	return c > 0x7f \|\| (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
	}

	/**
	* set loadlut - load the LUT table
	* @p: user table
	*
	* Load the LUT table from user space. The caller must hold the console
	* lock. Make a temporary copy so a partial update doesn't make a mess.
	*/
	int sel_loadlut(char __user *p)
	{
	u32 tmplut[ARRAY_SIZE(inwordLut)];
	if (copy_from_user(tmplut, (u32 __user *)(p+4), sizeof(inwordLut)))
	return -EFAULT;
	memcpy(inwordLut, tmplut, sizeof(inwordLut));
	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));
	}

	/* constrain v such that v <= u */
	static inline unsigned short limit(const unsigned short v, const unsigned short u)
	{
	return (v > u) ? u : v;
	}

	/* stores the char in UTF8 and returns the number of bytes used (1-3) */
	static int store_utf8(u16 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 {
	/* 1110** 10** 10**** */
	p[0] = 0xe0 \| (c >> 12);
	p[1] = 0x80 \| ((c >> 6) & 0x3f);
	p[2] = 0x80 \| (c & 0x3f);
	return 3;
	}
	}

	/**
	* set_selection - set the current selection.
	* @sel: user selection info
	* @tty: the console tty
	*
	* Invoked by the ioctl handle for the vt layer.
	*
	* 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(const struct tiocl_selection __user sel, struct tty_struct tty)
	{
	struct vc_data *vc = vc_cons[fg_console].d;
	int new_sel_start, new_sel_end, spc;
	struct tiocl_selection v;
	char bp, obp;
	int i, ps, pe, multiplier;
	u16 c;
	int mode;

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

	v.xs = limit(v.xs - 1, vc->vc_cols - 1);
	v.ys = limit(v.ys - 1, vc->vc_rows - 1);
	v.xe = limit(v.xe - 1, vc->vc_cols - 1);
	v.ye = limit(v.ye - 1, vc->vc_rows - 1);
	ps = v.ys * vc->vc_size_row + (v.xs << 1);
	pe = v.ye * vc->vc_size_row + (v.xe << 1);

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

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

	if (ps > pe) /* make sel_start <= sel_end */
	swap(ps, pe);

	if (sel_cons != vc_cons[fg_console].d) {
	clear_selection();
	sel_cons = vc_cons[fg_console].d;
	}
	mode = vt_do_kdgkbmode(fg_console);
	if (mode == K_UNICODE)
	use_unicode = 1;
	else
	use_unicode = 0;

	switch (v.sel_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 = isspace(sel_pos(ps));
	for (new_sel_start = ps; ; ps -= 2)
	{
	if ((spc && !isspace(sel_pos(ps))) \|\|
	(!spc && !inword(sel_pos(ps))))
	break;
	new_sel_start = ps;
	if (!(ps % vc->vc_size_row))
	break;
	}
	spc = isspace(sel_pos(pe));
	for (new_sel_end = pe; ; pe += 2)
	{
	if ((spc && !isspace(sel_pos(pe))) \|\|
	(!spc && !inword(sel_pos(pe))))
	break;
	new_sel_end = pe;
	if (!((pe + 2) % vc->vc_size_row))
	break;
	}
	break;
	case TIOCL_SELLINE: /* line-by-line selection */
	new_sel_start = ps - ps % vc->vc_size_row;
	new_sel_end = pe + vc->vc_size_row
	- pe % 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) &&
	isspace(sel_pos(new_sel_end))) {
	for (pe = new_sel_end + 2; ; pe += 2)
	if (!isspace(sel_pos(pe)) \|\|
	atedge(pe, vc->vc_size_row))
	break;
	if (isspace(sel_pos(pe)))
	new_sel_end = pe;
	}
	if (sel_start == -1) /* no current selection */
	highlight(new_sel_start, new_sel_end);
	else if (new_sel_start == sel_start)
	{
	if (new_sel_end == sel_end) /* no action required */
	return 0;
	else if (new_sel_end > sel_end) /* extend to right */
	highlight(sel_end + 2, new_sel_end);
	else /* contract from right */
	highlight(new_sel_end + 2, sel_end);
	}
	else if (new_sel_end == sel_end)
	{
	if (new_sel_start < sel_start) /* extend to left */
	highlight(new_sel_start, sel_start - 2);
	else /* contract from left */
	highlight(sel_start, new_sel_start - 2);
	}
	else /* some other case; start selection from scratch */
	{
	clear_selection();
	highlight(new_sel_start, new_sel_end);
	}
	sel_start = new_sel_start;
	sel_end = new_sel_end;

	/* Allocate a new buffer before freeing the old one ... */
	multiplier = use_unicode ? 3 : 1; /* chars can take up to 3 bytes */
	bp = kmalloc_array((sel_end - sel_start) / 2 + 1, multiplier,
	GFP_KERNEL);
	if (!bp) {
	printk(KERN_WARNING "selection: kmalloc() failed\n");
	clear_selection();
	return -ENOMEM;
	}
	kfree(sel_buffer);
	sel_buffer = bp;

	obp = bp;
	for (i = sel_start; i <= sel_end; i += 2) {
	c = sel_pos(i);
	if (use_unicode)
	bp += store_utf8(c, bp);
	else
	*bp++ = c;
	if (!isspace(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;
	}
	}
	sel_buffer_lth = bp - sel_buffer;
	return 0;
	}

	/* 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;
	unsigned int count;
	struct tty_ldisc *ld;
	DECLARE_WAITQUEUE(wait, current);

	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);
	while (sel_buffer && sel_buffer_lth > pasted) {
	set_current_state(TASK_INTERRUPTIBLE);
	if (tty_throttled(tty)) {
	schedule();
	continue;
	}
	__set_current_state(TASK_RUNNING);
	count = sel_buffer_lth - pasted;
	count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
	count);
	pasted += count;
	}
	remove_wait_queue(&vc->paste_wait, &wait);
	__set_current_state(TASK_RUNNING);

	tty_buffer_unlock_exclusive(&vc->port);
	tty_ldisc_deref(ld);
	return 0;
	}