xref: /openbmc/linux/drivers/tty/vt/selection.c (revision 81d67439)
1 /*
2  * This module exports the functions:
3  *
4  *     'int set_selection(struct tiocl_selection __user *, struct tty_struct *)'
5  *     'void clear_selection(void)'
6  *     'int paste_selection(struct tty_struct *)'
7  *     'int sel_loadlut(char __user *)'
8  *
9  * Now that /dev/vcs exists, most of this can disappear again.
10  */
11 
12 #include <linux/module.h>
13 #include <linux/tty.h>
14 #include <linux/sched.h>
15 #include <linux/mm.h>
16 #include <linux/slab.h>
17 #include <linux/types.h>
18 
19 #include <asm/uaccess.h>
20 
21 #include <linux/kbd_kern.h>
22 #include <linux/vt_kern.h>
23 #include <linux/consolemap.h>
24 #include <linux/selection.h>
25 #include <linux/tiocl.h>
26 #include <linux/console.h>
27 
28 /* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
29 #define isspace(c)	((c) == ' ')
30 
31 extern void poke_blanked_console(void);
32 
33 /* Variables for selection control. */
34 /* Use a dynamic buffer, instead of static (Dec 1994) */
35 struct vc_data *sel_cons;		/* must not be deallocated */
36 static int use_unicode;
37 static volatile int sel_start = -1; 	/* cleared by clear_selection */
38 static int sel_end;
39 static int sel_buffer_lth;
40 static char *sel_buffer;
41 
42 /* clear_selection, highlight and highlight_pointer can be called
43    from interrupt (via scrollback/front) */
44 
45 /* set reverse video on characters s-e of console with selection. */
46 static inline void highlight(const int s, const int e)
47 {
48 	invert_screen(sel_cons, s, e-s+2, 1);
49 }
50 
51 /* use complementary color to show the pointer */
52 static inline void highlight_pointer(const int where)
53 {
54 	complement_pos(sel_cons, where);
55 }
56 
57 static u16
58 sel_pos(int n)
59 {
60 	return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
61 				use_unicode);
62 }
63 
64 /* remove the current selection highlight, if any,
65    from the console holding the selection. */
66 void
67 clear_selection(void) {
68 	highlight_pointer(-1); /* hide the pointer */
69 	if (sel_start != -1) {
70 		highlight(sel_start, sel_end);
71 		sel_start = -1;
72 	}
73 }
74 
75 /*
76  * User settable table: what characters are to be considered alphabetic?
77  * 256 bits
78  */
79 static u32 inwordLut[8]={
80   0x00000000, /* control chars     */
81   0x03FF0000, /* digits            */
82   0x87FFFFFE, /* uppercase and '_' */
83   0x07FFFFFE, /* lowercase         */
84   0x00000000,
85   0x00000000,
86   0xFF7FFFFF, /* latin-1 accented letters, not multiplication sign */
87   0xFF7FFFFF  /* latin-1 accented letters, not division sign */
88 };
89 
90 static inline int inword(const u16 c) {
91 	return c > 0xff || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
92 }
93 
94 /* set inwordLut contents. Invoked by ioctl(). */
95 int sel_loadlut(char __user *p)
96 {
97 	return copy_from_user(inwordLut, (u32 __user *)(p+4), 32) ? -EFAULT : 0;
98 }
99 
100 /* does screen address p correspond to character at LH/RH edge of screen? */
101 static inline int atedge(const int p, int size_row)
102 {
103 	return (!(p % size_row)	|| !((p + 2) % size_row));
104 }
105 
106 /* constrain v such that v <= u */
107 static inline unsigned short limit(const unsigned short v, const unsigned short u)
108 {
109 	return (v > u) ? u : v;
110 }
111 
112 /* stores the char in UTF8 and returns the number of bytes used (1-3) */
113 static int store_utf8(u16 c, char *p)
114 {
115 	if (c < 0x80) {
116 		/*  0******* */
117 		p[0] = c;
118 		return 1;
119 	} else if (c < 0x800) {
120 		/* 110***** 10****** */
121 		p[0] = 0xc0 | (c >> 6);
122 		p[1] = 0x80 | (c & 0x3f);
123 		return 2;
124     	} else {
125 		/* 1110**** 10****** 10****** */
126 		p[0] = 0xe0 | (c >> 12);
127 		p[1] = 0x80 | ((c >> 6) & 0x3f);
128 		p[2] = 0x80 | (c & 0x3f);
129 		return 3;
130     	}
131 }
132 
133 /* set the current selection. Invoked by ioctl() or by kernel code. */
134 int set_selection(const struct tiocl_selection __user *sel, struct tty_struct *tty)
135 {
136 	struct vc_data *vc = vc_cons[fg_console].d;
137 	int sel_mode, new_sel_start, new_sel_end, spc;
138 	char *bp, *obp;
139 	int i, ps, pe, multiplier;
140 	u16 c;
141 	struct kbd_struct *kbd = kbd_table + fg_console;
142 
143 	poke_blanked_console();
144 
145 	{ unsigned short xs, ys, xe, ye;
146 
147 	  if (!access_ok(VERIFY_READ, sel, sizeof(*sel)))
148 		return -EFAULT;
149 	  __get_user(xs, &sel->xs);
150 	  __get_user(ys, &sel->ys);
151 	  __get_user(xe, &sel->xe);
152 	  __get_user(ye, &sel->ye);
153 	  __get_user(sel_mode, &sel->sel_mode);
154 	  xs--; ys--; xe--; ye--;
155 	  xs = limit(xs, vc->vc_cols - 1);
156 	  ys = limit(ys, vc->vc_rows - 1);
157 	  xe = limit(xe, vc->vc_cols - 1);
158 	  ye = limit(ye, vc->vc_rows - 1);
159 	  ps = ys * vc->vc_size_row + (xs << 1);
160 	  pe = ye * vc->vc_size_row + (xe << 1);
161 
162 	  if (sel_mode == TIOCL_SELCLEAR) {
163 	      /* useful for screendump without selection highlights */
164 	      clear_selection();
165 	      return 0;
166 	  }
167 
168 	  if (mouse_reporting() && (sel_mode & TIOCL_SELMOUSEREPORT)) {
169 	      mouse_report(tty, sel_mode & TIOCL_SELBUTTONMASK, xs, ys);
170 	      return 0;
171 	  }
172         }
173 
174 	if (ps > pe)	/* make sel_start <= sel_end */
175 	{
176 		int tmp = ps;
177 		ps = pe;
178 		pe = tmp;
179 	}
180 
181 	if (sel_cons != vc_cons[fg_console].d) {
182 		clear_selection();
183 		sel_cons = vc_cons[fg_console].d;
184 	}
185 	use_unicode = kbd && kbd->kbdmode == VC_UNICODE;
186 
187 	switch (sel_mode)
188 	{
189 		case TIOCL_SELCHAR:	/* character-by-character selection */
190 			new_sel_start = ps;
191 			new_sel_end = pe;
192 			break;
193 		case TIOCL_SELWORD:	/* word-by-word selection */
194 			spc = isspace(sel_pos(ps));
195 			for (new_sel_start = ps; ; ps -= 2)
196 			{
197 				if ((spc && !isspace(sel_pos(ps))) ||
198 				    (!spc && !inword(sel_pos(ps))))
199 					break;
200 				new_sel_start = ps;
201 				if (!(ps % vc->vc_size_row))
202 					break;
203 			}
204 			spc = isspace(sel_pos(pe));
205 			for (new_sel_end = pe; ; pe += 2)
206 			{
207 				if ((spc && !isspace(sel_pos(pe))) ||
208 				    (!spc && !inword(sel_pos(pe))))
209 					break;
210 				new_sel_end = pe;
211 				if (!((pe + 2) % vc->vc_size_row))
212 					break;
213 			}
214 			break;
215 		case TIOCL_SELLINE:	/* line-by-line selection */
216 			new_sel_start = ps - ps % vc->vc_size_row;
217 			new_sel_end = pe + vc->vc_size_row
218 				    - pe % vc->vc_size_row - 2;
219 			break;
220 		case TIOCL_SELPOINTER:
221 			highlight_pointer(pe);
222 			return 0;
223 		default:
224 			return -EINVAL;
225 	}
226 
227 	/* remove the pointer */
228 	highlight_pointer(-1);
229 
230 	/* select to end of line if on trailing space */
231 	if (new_sel_end > new_sel_start &&
232 		!atedge(new_sel_end, vc->vc_size_row) &&
233 		isspace(sel_pos(new_sel_end))) {
234 		for (pe = new_sel_end + 2; ; pe += 2)
235 			if (!isspace(sel_pos(pe)) ||
236 			    atedge(pe, vc->vc_size_row))
237 				break;
238 		if (isspace(sel_pos(pe)))
239 			new_sel_end = pe;
240 	}
241 	if (sel_start == -1)	/* no current selection */
242 		highlight(new_sel_start, new_sel_end);
243 	else if (new_sel_start == sel_start)
244 	{
245 		if (new_sel_end == sel_end)	/* no action required */
246 			return 0;
247 		else if (new_sel_end > sel_end)	/* extend to right */
248 			highlight(sel_end + 2, new_sel_end);
249 		else				/* contract from right */
250 			highlight(new_sel_end + 2, sel_end);
251 	}
252 	else if (new_sel_end == sel_end)
253 	{
254 		if (new_sel_start < sel_start)	/* extend to left */
255 			highlight(new_sel_start, sel_start - 2);
256 		else				/* contract from left */
257 			highlight(sel_start, new_sel_start - 2);
258 	}
259 	else	/* some other case; start selection from scratch */
260 	{
261 		clear_selection();
262 		highlight(new_sel_start, new_sel_end);
263 	}
264 	sel_start = new_sel_start;
265 	sel_end = new_sel_end;
266 
267 	/* Allocate a new buffer before freeing the old one ... */
268 	multiplier = use_unicode ? 3 : 1;  /* chars can take up to 3 bytes */
269 	bp = kmalloc(((sel_end-sel_start)/2+1)*multiplier, GFP_KERNEL);
270 	if (!bp) {
271 		printk(KERN_WARNING "selection: kmalloc() failed\n");
272 		clear_selection();
273 		return -ENOMEM;
274 	}
275 	kfree(sel_buffer);
276 	sel_buffer = bp;
277 
278 	obp = bp;
279 	for (i = sel_start; i <= sel_end; i += 2) {
280 		c = sel_pos(i);
281 		if (use_unicode)
282 			bp += store_utf8(c, bp);
283 		else
284 			*bp++ = c;
285 		if (!isspace(c))
286 			obp = bp;
287 		if (! ((i + 2) % vc->vc_size_row)) {
288 			/* strip trailing blanks from line and add newline,
289 			   unless non-space at end of line. */
290 			if (obp != bp) {
291 				bp = obp;
292 				*bp++ = '\r';
293 			}
294 			obp = bp;
295 		}
296 	}
297 	sel_buffer_lth = bp - sel_buffer;
298 	return 0;
299 }
300 
301 /* Insert the contents of the selection buffer into the
302  * queue of the tty associated with the current console.
303  * Invoked by ioctl().
304  */
305 int paste_selection(struct tty_struct *tty)
306 {
307 	struct vc_data *vc = tty->driver_data;
308 	int	pasted = 0;
309 	unsigned int count;
310 	struct  tty_ldisc *ld;
311 	DECLARE_WAITQUEUE(wait, current);
312 
313 	/* always called with BTM from vt_ioctl */
314 	WARN_ON(!tty_locked());
315 
316 	console_lock();
317 	poke_blanked_console();
318 	console_unlock();
319 
320 	ld = tty_ldisc_ref(tty);
321 	if (!ld) {
322 		tty_unlock();
323 		ld = tty_ldisc_ref_wait(tty);
324 		tty_lock();
325 	}
326 
327 	add_wait_queue(&vc->paste_wait, &wait);
328 	while (sel_buffer && sel_buffer_lth > pasted) {
329 		set_current_state(TASK_INTERRUPTIBLE);
330 		if (test_bit(TTY_THROTTLED, &tty->flags)) {
331 			schedule();
332 			continue;
333 		}
334 		count = sel_buffer_lth - pasted;
335 		count = min(count, tty->receive_room);
336 		tty->ldisc->ops->receive_buf(tty, sel_buffer + pasted,
337 								NULL, count);
338 		pasted += count;
339 	}
340 	remove_wait_queue(&vc->paste_wait, &wait);
341 	__set_current_state(TASK_RUNNING);
342 
343 	tty_ldisc_deref(ld);
344 	return 0;
345 }
346