xref: /openbmc/linux/drivers/tty/vt/selection.c (revision aac5987a)
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 <linux/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 #include <linux/tty_flip.h>
28 
29 /* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
30 #define isspace(c)	((c) == ' ')
31 
32 extern void poke_blanked_console(void);
33 
34 /* FIXME: all this needs locking */
35 /* Variables for selection control. */
36 /* Use a dynamic buffer, instead of static (Dec 1994) */
37 struct vc_data *sel_cons;		/* must not be deallocated */
38 static int use_unicode;
39 static volatile int sel_start = -1; 	/* cleared by clear_selection */
40 static int sel_end;
41 static int sel_buffer_lth;
42 static char *sel_buffer;
43 
44 /* clear_selection, highlight and highlight_pointer can be called
45    from interrupt (via scrollback/front) */
46 
47 /* set reverse video on characters s-e of console with selection. */
48 static inline void highlight(const int s, const int e)
49 {
50 	invert_screen(sel_cons, s, e-s+2, 1);
51 }
52 
53 /* use complementary color to show the pointer */
54 static inline void highlight_pointer(const int where)
55 {
56 	complement_pos(sel_cons, where);
57 }
58 
59 static u16
60 sel_pos(int n)
61 {
62 	return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
63 				use_unicode);
64 }
65 
66 /**
67  *	clear_selection		-	remove current selection
68  *
69  *	Remove the current selection highlight, if any from the console
70  *	holding the selection. The caller must hold the console lock.
71  */
72 void clear_selection(void)
73 {
74 	highlight_pointer(-1); /* hide the pointer */
75 	if (sel_start != -1) {
76 		highlight(sel_start, sel_end);
77 		sel_start = -1;
78 	}
79 }
80 
81 /*
82  * User settable table: what characters are to be considered alphabetic?
83  * 256 bits. Locked by the console lock.
84  */
85 static u32 inwordLut[8]={
86   0x00000000, /* control chars     */
87   0x03FF0000, /* digits            */
88   0x87FFFFFE, /* uppercase and '_' */
89   0x07FFFFFE, /* lowercase         */
90   0x00000000,
91   0x00000000,
92   0xFF7FFFFF, /* latin-1 accented letters, not multiplication sign */
93   0xFF7FFFFF  /* latin-1 accented letters, not division sign */
94 };
95 
96 static inline int inword(const u16 c) {
97 	return c > 0xff || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
98 }
99 
100 /**
101  *	set loadlut		-	load the LUT table
102  *	@p: user table
103  *
104  *	Load the LUT table from user space. The caller must hold the console
105  *	lock. Make a temporary copy so a partial update doesn't make a mess.
106  */
107 int sel_loadlut(char __user *p)
108 {
109 	u32 tmplut[8];
110 	if (copy_from_user(tmplut, (u32 __user *)(p+4), 32))
111 		return -EFAULT;
112 	memcpy(inwordLut, tmplut, 32);
113 	return 0;
114 }
115 
116 /* does screen address p correspond to character at LH/RH edge of screen? */
117 static inline int atedge(const int p, int size_row)
118 {
119 	return (!(p % size_row)	|| !((p + 2) % size_row));
120 }
121 
122 /* constrain v such that v <= u */
123 static inline unsigned short limit(const unsigned short v, const unsigned short u)
124 {
125 	return (v > u) ? u : v;
126 }
127 
128 /* stores the char in UTF8 and returns the number of bytes used (1-3) */
129 static int store_utf8(u16 c, char *p)
130 {
131 	if (c < 0x80) {
132 		/*  0******* */
133 		p[0] = c;
134 		return 1;
135 	} else if (c < 0x800) {
136 		/* 110***** 10****** */
137 		p[0] = 0xc0 | (c >> 6);
138 		p[1] = 0x80 | (c & 0x3f);
139 		return 2;
140     	} else {
141 		/* 1110**** 10****** 10****** */
142 		p[0] = 0xe0 | (c >> 12);
143 		p[1] = 0x80 | ((c >> 6) & 0x3f);
144 		p[2] = 0x80 | (c & 0x3f);
145 		return 3;
146     	}
147 }
148 
149 /**
150  *	set_selection		- 	set the current selection.
151  *	@sel: user selection info
152  *	@tty: the console tty
153  *
154  *	Invoked by the ioctl handle for the vt layer.
155  *
156  *	The entire selection process is managed under the console_lock. It's
157  *	 a lot under the lock but its hardly a performance path
158  */
159 int set_selection(const struct tiocl_selection __user *sel, struct tty_struct *tty)
160 {
161 	struct vc_data *vc = vc_cons[fg_console].d;
162 	int sel_mode, new_sel_start, new_sel_end, spc;
163 	char *bp, *obp;
164 	int i, ps, pe, multiplier;
165 	u16 c;
166 	int mode;
167 
168 	poke_blanked_console();
169 
170 	{ unsigned short xs, ys, xe, ye;
171 
172 	  if (!access_ok(VERIFY_READ, sel, sizeof(*sel)))
173 		return -EFAULT;
174 	  __get_user(xs, &sel->xs);
175 	  __get_user(ys, &sel->ys);
176 	  __get_user(xe, &sel->xe);
177 	  __get_user(ye, &sel->ye);
178 	  __get_user(sel_mode, &sel->sel_mode);
179 	  xs--; ys--; xe--; ye--;
180 	  xs = limit(xs, vc->vc_cols - 1);
181 	  ys = limit(ys, vc->vc_rows - 1);
182 	  xe = limit(xe, vc->vc_cols - 1);
183 	  ye = limit(ye, vc->vc_rows - 1);
184 	  ps = ys * vc->vc_size_row + (xs << 1);
185 	  pe = ye * vc->vc_size_row + (xe << 1);
186 
187 	  if (sel_mode == TIOCL_SELCLEAR) {
188 	      /* useful for screendump without selection highlights */
189 	      clear_selection();
190 	      return 0;
191 	  }
192 
193 	  if (mouse_reporting() && (sel_mode & TIOCL_SELMOUSEREPORT)) {
194 	      mouse_report(tty, sel_mode & TIOCL_SELBUTTONMASK, xs, ys);
195 	      return 0;
196 	  }
197         }
198 
199 	if (ps > pe)	/* make sel_start <= sel_end */
200 	{
201 		int tmp = ps;
202 		ps = pe;
203 		pe = tmp;
204 	}
205 
206 	if (sel_cons != vc_cons[fg_console].d) {
207 		clear_selection();
208 		sel_cons = vc_cons[fg_console].d;
209 	}
210 	mode = vt_do_kdgkbmode(fg_console);
211 	if (mode == K_UNICODE)
212 		use_unicode = 1;
213 	else
214 		use_unicode = 0;
215 
216 	switch (sel_mode)
217 	{
218 		case TIOCL_SELCHAR:	/* character-by-character selection */
219 			new_sel_start = ps;
220 			new_sel_end = pe;
221 			break;
222 		case TIOCL_SELWORD:	/* word-by-word selection */
223 			spc = isspace(sel_pos(ps));
224 			for (new_sel_start = ps; ; ps -= 2)
225 			{
226 				if ((spc && !isspace(sel_pos(ps))) ||
227 				    (!spc && !inword(sel_pos(ps))))
228 					break;
229 				new_sel_start = ps;
230 				if (!(ps % vc->vc_size_row))
231 					break;
232 			}
233 			spc = isspace(sel_pos(pe));
234 			for (new_sel_end = pe; ; pe += 2)
235 			{
236 				if ((spc && !isspace(sel_pos(pe))) ||
237 				    (!spc && !inword(sel_pos(pe))))
238 					break;
239 				new_sel_end = pe;
240 				if (!((pe + 2) % vc->vc_size_row))
241 					break;
242 			}
243 			break;
244 		case TIOCL_SELLINE:	/* line-by-line selection */
245 			new_sel_start = ps - ps % vc->vc_size_row;
246 			new_sel_end = pe + vc->vc_size_row
247 				    - pe % vc->vc_size_row - 2;
248 			break;
249 		case TIOCL_SELPOINTER:
250 			highlight_pointer(pe);
251 			return 0;
252 		default:
253 			return -EINVAL;
254 	}
255 
256 	/* remove the pointer */
257 	highlight_pointer(-1);
258 
259 	/* select to end of line if on trailing space */
260 	if (new_sel_end > new_sel_start &&
261 		!atedge(new_sel_end, vc->vc_size_row) &&
262 		isspace(sel_pos(new_sel_end))) {
263 		for (pe = new_sel_end + 2; ; pe += 2)
264 			if (!isspace(sel_pos(pe)) ||
265 			    atedge(pe, vc->vc_size_row))
266 				break;
267 		if (isspace(sel_pos(pe)))
268 			new_sel_end = pe;
269 	}
270 	if (sel_start == -1)	/* no current selection */
271 		highlight(new_sel_start, new_sel_end);
272 	else if (new_sel_start == sel_start)
273 	{
274 		if (new_sel_end == sel_end)	/* no action required */
275 			return 0;
276 		else if (new_sel_end > sel_end)	/* extend to right */
277 			highlight(sel_end + 2, new_sel_end);
278 		else				/* contract from right */
279 			highlight(new_sel_end + 2, sel_end);
280 	}
281 	else if (new_sel_end == sel_end)
282 	{
283 		if (new_sel_start < sel_start)	/* extend to left */
284 			highlight(new_sel_start, sel_start - 2);
285 		else				/* contract from left */
286 			highlight(sel_start, new_sel_start - 2);
287 	}
288 	else	/* some other case; start selection from scratch */
289 	{
290 		clear_selection();
291 		highlight(new_sel_start, new_sel_end);
292 	}
293 	sel_start = new_sel_start;
294 	sel_end = new_sel_end;
295 
296 	/* Allocate a new buffer before freeing the old one ... */
297 	multiplier = use_unicode ? 3 : 1;  /* chars can take up to 3 bytes */
298 	bp = kmalloc(((sel_end-sel_start)/2+1)*multiplier, GFP_KERNEL);
299 	if (!bp) {
300 		printk(KERN_WARNING "selection: kmalloc() failed\n");
301 		clear_selection();
302 		return -ENOMEM;
303 	}
304 	kfree(sel_buffer);
305 	sel_buffer = bp;
306 
307 	obp = bp;
308 	for (i = sel_start; i <= sel_end; i += 2) {
309 		c = sel_pos(i);
310 		if (use_unicode)
311 			bp += store_utf8(c, bp);
312 		else
313 			*bp++ = c;
314 		if (!isspace(c))
315 			obp = bp;
316 		if (! ((i + 2) % vc->vc_size_row)) {
317 			/* strip trailing blanks from line and add newline,
318 			   unless non-space at end of line. */
319 			if (obp != bp) {
320 				bp = obp;
321 				*bp++ = '\r';
322 			}
323 			obp = bp;
324 		}
325 	}
326 	sel_buffer_lth = bp - sel_buffer;
327 	return 0;
328 }
329 
330 /* Insert the contents of the selection buffer into the
331  * queue of the tty associated with the current console.
332  * Invoked by ioctl().
333  *
334  * Locking: called without locks. Calls the ldisc wrongly with
335  * unsafe methods,
336  */
337 int paste_selection(struct tty_struct *tty)
338 {
339 	struct vc_data *vc = tty->driver_data;
340 	int	pasted = 0;
341 	unsigned int count;
342 	struct  tty_ldisc *ld;
343 	DECLARE_WAITQUEUE(wait, current);
344 
345 	console_lock();
346 	poke_blanked_console();
347 	console_unlock();
348 
349 	ld = tty_ldisc_ref_wait(tty);
350 	if (!ld)
351 		return -EIO;	/* ldisc was hung up */
352 	tty_buffer_lock_exclusive(&vc->port);
353 
354 	add_wait_queue(&vc->paste_wait, &wait);
355 	while (sel_buffer && sel_buffer_lth > pasted) {
356 		set_current_state(TASK_INTERRUPTIBLE);
357 		if (tty_throttled(tty)) {
358 			schedule();
359 			continue;
360 		}
361 		__set_current_state(TASK_RUNNING);
362 		count = sel_buffer_lth - pasted;
363 		count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
364 					      count);
365 		pasted += count;
366 	}
367 	remove_wait_queue(&vc->paste_wait, &wait);
368 	__set_current_state(TASK_RUNNING);
369 
370 	tty_buffer_unlock_exclusive(&vc->port);
371 	tty_ldisc_deref(ld);
372 	return 0;
373 }
374