xref: /openbmc/linux/drivers/tty/vt/selection.c (revision f17f06a0)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * This module exports the functions:
4  *
5  *     'int set_selection_user(struct tiocl_selection __user *,
6  *			       struct tty_struct *)'
7  *     'int set_selection_kernel(struct tiocl_selection *, struct tty_struct *)'
8  *     'void clear_selection(void)'
9  *     'int paste_selection(struct tty_struct *)'
10  *     'int sel_loadlut(char __user *)'
11  *
12  * Now that /dev/vcs exists, most of this can disappear again.
13  */
14 
15 #include <linux/module.h>
16 #include <linux/tty.h>
17 #include <linux/sched.h>
18 #include <linux/mm.h>
19 #include <linux/mutex.h>
20 #include <linux/slab.h>
21 #include <linux/types.h>
22 
23 #include <linux/uaccess.h>
24 
25 #include <linux/kbd_kern.h>
26 #include <linux/vt_kern.h>
27 #include <linux/consolemap.h>
28 #include <linux/selection.h>
29 #include <linux/tiocl.h>
30 #include <linux/console.h>
31 #include <linux/tty_flip.h>
32 
33 #include <linux/sched/signal.h>
34 
35 /* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
36 #define isspace(c)	((c) == ' ')
37 
38 extern void poke_blanked_console(void);
39 
40 /* FIXME: all this needs locking */
41 /* Variables for selection control. */
42 /* Use a dynamic buffer, instead of static (Dec 1994) */
43 struct vc_data *sel_cons;		/* must not be deallocated */
44 static int use_unicode;
45 static volatile int sel_start = -1; 	/* cleared by clear_selection */
46 static int sel_end;
47 static int sel_buffer_lth;
48 static char *sel_buffer;
49 static DEFINE_MUTEX(sel_lock);
50 
51 /* clear_selection, highlight and highlight_pointer can be called
52    from interrupt (via scrollback/front) */
53 
54 /* set reverse video on characters s-e of console with selection. */
55 static inline void highlight(const int s, const int e)
56 {
57 	invert_screen(sel_cons, s, e-s+2, 1);
58 }
59 
60 /* use complementary color to show the pointer */
61 static inline void highlight_pointer(const int where)
62 {
63 	complement_pos(sel_cons, where);
64 }
65 
66 static u32
67 sel_pos(int n)
68 {
69 	if (use_unicode)
70 		return screen_glyph_unicode(sel_cons, n / 2);
71 	return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
72 				0);
73 }
74 
75 /**
76  *	clear_selection		-	remove current selection
77  *
78  *	Remove the current selection highlight, if any from the console
79  *	holding the selection. The caller must hold the console lock.
80  */
81 void clear_selection(void)
82 {
83 	highlight_pointer(-1); /* hide the pointer */
84 	if (sel_start != -1) {
85 		highlight(sel_start, sel_end);
86 		sel_start = -1;
87 	}
88 }
89 EXPORT_SYMBOL_GPL(clear_selection);
90 
91 /*
92  * User settable table: what characters are to be considered alphabetic?
93  * 128 bits. Locked by the console lock.
94  */
95 static u32 inwordLut[]={
96   0x00000000, /* control chars     */
97   0x03FFE000, /* digits and "-./"  */
98   0x87FFFFFE, /* uppercase and '_' */
99   0x07FFFFFE, /* lowercase         */
100 };
101 
102 static inline int inword(const u32 c)
103 {
104 	return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
105 }
106 
107 /**
108  *	set loadlut		-	load the LUT table
109  *	@p: user table
110  *
111  *	Load the LUT table from user space. The caller must hold the console
112  *	lock. Make a temporary copy so a partial update doesn't make a mess.
113  */
114 int sel_loadlut(char __user *p)
115 {
116 	u32 tmplut[ARRAY_SIZE(inwordLut)];
117 	if (copy_from_user(tmplut, (u32 __user *)(p+4), sizeof(inwordLut)))
118 		return -EFAULT;
119 	memcpy(inwordLut, tmplut, sizeof(inwordLut));
120 	return 0;
121 }
122 
123 /* does screen address p correspond to character at LH/RH edge of screen? */
124 static inline int atedge(const int p, int size_row)
125 {
126 	return (!(p % size_row)	|| !((p + 2) % size_row));
127 }
128 
129 /* stores the char in UTF8 and returns the number of bytes used (1-4) */
130 static int store_utf8(u32 c, char *p)
131 {
132 	if (c < 0x80) {
133 		/*  0******* */
134 		p[0] = c;
135 		return 1;
136 	} else if (c < 0x800) {
137 		/* 110***** 10****** */
138 		p[0] = 0xc0 | (c >> 6);
139 		p[1] = 0x80 | (c & 0x3f);
140 		return 2;
141 	} else if (c < 0x10000) {
142 		/* 1110**** 10****** 10****** */
143 		p[0] = 0xe0 | (c >> 12);
144 		p[1] = 0x80 | ((c >> 6) & 0x3f);
145 		p[2] = 0x80 | (c & 0x3f);
146 		return 3;
147 	} else if (c < 0x110000) {
148 		/* 11110*** 10****** 10****** 10****** */
149 		p[0] = 0xf0 | (c >> 18);
150 		p[1] = 0x80 | ((c >> 12) & 0x3f);
151 		p[2] = 0x80 | ((c >> 6) & 0x3f);
152 		p[3] = 0x80 | (c & 0x3f);
153 		return 4;
154 	} else {
155 		/* outside Unicode, replace with U+FFFD */
156 		p[0] = 0xef;
157 		p[1] = 0xbf;
158 		p[2] = 0xbd;
159 		return 3;
160 	}
161 }
162 
163 /**
164  *	set_selection_user	-	set the current selection.
165  *	@sel: user selection info
166  *	@tty: the console tty
167  *
168  *	Invoked by the ioctl handle for the vt layer.
169  *
170  *	The entire selection process is managed under the console_lock. It's
171  *	 a lot under the lock but its hardly a performance path
172  */
173 int set_selection_user(const struct tiocl_selection __user *sel,
174 		       struct tty_struct *tty)
175 {
176 	struct tiocl_selection v;
177 
178 	if (copy_from_user(&v, sel, sizeof(*sel)))
179 		return -EFAULT;
180 
181 	return set_selection_kernel(&v, tty);
182 }
183 
184 static int __set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
185 {
186 	struct vc_data *vc = vc_cons[fg_console].d;
187 	int new_sel_start, new_sel_end, spc;
188 	char *bp, *obp;
189 	int i, ps, pe, multiplier;
190 	u32 c;
191 	int mode, ret = 0;
192 
193 	poke_blanked_console();
194 
195 	v->xs = min_t(u16, v->xs - 1, vc->vc_cols - 1);
196 	v->ys = min_t(u16, v->ys - 1, vc->vc_rows - 1);
197 	v->xe = min_t(u16, v->xe - 1, vc->vc_cols - 1);
198 	v->ye = min_t(u16, v->ye - 1, vc->vc_rows - 1);
199 	ps = v->ys * vc->vc_size_row + (v->xs << 1);
200 	pe = v->ye * vc->vc_size_row + (v->xe << 1);
201 
202 	if (v->sel_mode == TIOCL_SELCLEAR) {
203 		/* useful for screendump without selection highlights */
204 		clear_selection();
205 		return 0;
206 	}
207 
208 	if (mouse_reporting() && (v->sel_mode & TIOCL_SELMOUSEREPORT)) {
209 		mouse_report(tty, v->sel_mode & TIOCL_SELBUTTONMASK, v->xs,
210 			     v->ys);
211 		return 0;
212 	}
213 
214 	if (ps > pe)	/* make sel_start <= sel_end */
215 		swap(ps, pe);
216 
217 	if (sel_cons != vc_cons[fg_console].d) {
218 		clear_selection();
219 		sel_cons = vc_cons[fg_console].d;
220 	}
221 	mode = vt_do_kdgkbmode(fg_console);
222 	if (mode == K_UNICODE)
223 		use_unicode = 1;
224 	else
225 		use_unicode = 0;
226 
227 	switch (v->sel_mode)
228 	{
229 		case TIOCL_SELCHAR:	/* character-by-character selection */
230 			new_sel_start = ps;
231 			new_sel_end = pe;
232 			break;
233 		case TIOCL_SELWORD:	/* word-by-word selection */
234 			spc = isspace(sel_pos(ps));
235 			for (new_sel_start = ps; ; ps -= 2)
236 			{
237 				if ((spc && !isspace(sel_pos(ps))) ||
238 				    (!spc && !inword(sel_pos(ps))))
239 					break;
240 				new_sel_start = ps;
241 				if (!(ps % vc->vc_size_row))
242 					break;
243 			}
244 			spc = isspace(sel_pos(pe));
245 			for (new_sel_end = pe; ; pe += 2)
246 			{
247 				if ((spc && !isspace(sel_pos(pe))) ||
248 				    (!spc && !inword(sel_pos(pe))))
249 					break;
250 				new_sel_end = pe;
251 				if (!((pe + 2) % vc->vc_size_row))
252 					break;
253 			}
254 			break;
255 		case TIOCL_SELLINE:	/* line-by-line selection */
256 			new_sel_start = ps - ps % vc->vc_size_row;
257 			new_sel_end = pe + vc->vc_size_row
258 				    - pe % vc->vc_size_row - 2;
259 			break;
260 		case TIOCL_SELPOINTER:
261 			highlight_pointer(pe);
262 			return 0;
263 		default:
264 			return -EINVAL;
265 	}
266 
267 	/* remove the pointer */
268 	highlight_pointer(-1);
269 
270 	/* select to end of line if on trailing space */
271 	if (new_sel_end > new_sel_start &&
272 		!atedge(new_sel_end, vc->vc_size_row) &&
273 		isspace(sel_pos(new_sel_end))) {
274 		for (pe = new_sel_end + 2; ; pe += 2)
275 			if (!isspace(sel_pos(pe)) ||
276 			    atedge(pe, vc->vc_size_row))
277 				break;
278 		if (isspace(sel_pos(pe)))
279 			new_sel_end = pe;
280 	}
281 	if (sel_start == -1)	/* no current selection */
282 		highlight(new_sel_start, new_sel_end);
283 	else if (new_sel_start == sel_start)
284 	{
285 		if (new_sel_end == sel_end)	/* no action required */
286 			return 0;
287 		else if (new_sel_end > sel_end)	/* extend to right */
288 			highlight(sel_end + 2, new_sel_end);
289 		else				/* contract from right */
290 			highlight(new_sel_end + 2, sel_end);
291 	}
292 	else if (new_sel_end == sel_end)
293 	{
294 		if (new_sel_start < sel_start)	/* extend to left */
295 			highlight(new_sel_start, sel_start - 2);
296 		else				/* contract from left */
297 			highlight(sel_start, new_sel_start - 2);
298 	}
299 	else	/* some other case; start selection from scratch */
300 	{
301 		clear_selection();
302 		highlight(new_sel_start, new_sel_end);
303 	}
304 	sel_start = new_sel_start;
305 	sel_end = new_sel_end;
306 
307 	/* Allocate a new buffer before freeing the old one ... */
308 	multiplier = use_unicode ? 4 : 1;  /* chars can take up to 4 bytes */
309 	bp = kmalloc_array((sel_end - sel_start) / 2 + 1, multiplier,
310 			   GFP_KERNEL);
311 	if (!bp) {
312 		printk(KERN_WARNING "selection: kmalloc() failed\n");
313 		clear_selection();
314 		return -ENOMEM;
315 	}
316 	kfree(sel_buffer);
317 	sel_buffer = bp;
318 
319 	obp = bp;
320 	for (i = sel_start; i <= sel_end; i += 2) {
321 		c = sel_pos(i);
322 		if (use_unicode)
323 			bp += store_utf8(c, bp);
324 		else
325 			*bp++ = c;
326 		if (!isspace(c))
327 			obp = bp;
328 		if (! ((i + 2) % vc->vc_size_row)) {
329 			/* strip trailing blanks from line and add newline,
330 			   unless non-space at end of line. */
331 			if (obp != bp) {
332 				bp = obp;
333 				*bp++ = '\r';
334 			}
335 			obp = bp;
336 		}
337 	}
338 	sel_buffer_lth = bp - sel_buffer;
339 
340 	return ret;
341 }
342 
343 int set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
344 {
345 	int ret;
346 
347 	mutex_lock(&sel_lock);
348 	console_lock();
349 	ret = __set_selection_kernel(v, tty);
350 	console_unlock();
351 	mutex_unlock(&sel_lock);
352 
353 	return ret;
354 }
355 EXPORT_SYMBOL_GPL(set_selection_kernel);
356 
357 /* Insert the contents of the selection buffer into the
358  * queue of the tty associated with the current console.
359  * Invoked by ioctl().
360  *
361  * Locking: called without locks. Calls the ldisc wrongly with
362  * unsafe methods,
363  */
364 int paste_selection(struct tty_struct *tty)
365 {
366 	struct vc_data *vc = tty->driver_data;
367 	int	pasted = 0;
368 	unsigned int count;
369 	struct  tty_ldisc *ld;
370 	DECLARE_WAITQUEUE(wait, current);
371 	int ret = 0;
372 
373 	console_lock();
374 	poke_blanked_console();
375 	console_unlock();
376 
377 	ld = tty_ldisc_ref_wait(tty);
378 	if (!ld)
379 		return -EIO;	/* ldisc was hung up */
380 	tty_buffer_lock_exclusive(&vc->port);
381 
382 	add_wait_queue(&vc->paste_wait, &wait);
383 	mutex_lock(&sel_lock);
384 	while (sel_buffer && sel_buffer_lth > pasted) {
385 		set_current_state(TASK_INTERRUPTIBLE);
386 		if (signal_pending(current)) {
387 			ret = -EINTR;
388 			break;
389 		}
390 		if (tty_throttled(tty)) {
391 			mutex_unlock(&sel_lock);
392 			schedule();
393 			mutex_lock(&sel_lock);
394 			continue;
395 		}
396 		__set_current_state(TASK_RUNNING);
397 		count = sel_buffer_lth - pasted;
398 		count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
399 					      count);
400 		pasted += count;
401 	}
402 	mutex_unlock(&sel_lock);
403 	remove_wait_queue(&vc->paste_wait, &wait);
404 	__set_current_state(TASK_RUNNING);
405 
406 	tty_buffer_unlock_exclusive(&vc->port);
407 	tty_ldisc_deref(ld);
408 	return ret;
409 }
410 EXPORT_SYMBOL_GPL(paste_selection);
411