xref: /openbmc/linux/drivers/tty/vt/selection.c (revision 9cdb81c7)
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 /* FIXME: all this needs locking */
34 /* Variables for selection control. */
35 /* Use a dynamic buffer, instead of static (Dec 1994) */
36 struct vc_data *sel_cons;		/* must not be deallocated */
37 static int use_unicode;
38 static volatile int sel_start = -1; 	/* cleared by clear_selection */
39 static int sel_end;
40 static int sel_buffer_lth;
41 static char *sel_buffer;
42 
43 /* clear_selection, highlight and highlight_pointer can be called
44    from interrupt (via scrollback/front) */
45 
46 /* set reverse video on characters s-e of console with selection. */
47 static inline void highlight(const int s, const int e)
48 {
49 	invert_screen(sel_cons, s, e-s+2, 1);
50 }
51 
52 /* use complementary color to show the pointer */
53 static inline void highlight_pointer(const int where)
54 {
55 	complement_pos(sel_cons, where);
56 }
57 
58 static u16
59 sel_pos(int n)
60 {
61 	return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
62 				use_unicode);
63 }
64 
65 /**
66  *	clear_selection		-	remove current selection
67  *
68  *	Remove the current selection highlight, if any from the console
69  *	holding the selection. The caller must hold the console lock.
70  */
71 void clear_selection(void)
72 {
73 	highlight_pointer(-1); /* hide the pointer */
74 	if (sel_start != -1) {
75 		highlight(sel_start, sel_end);
76 		sel_start = -1;
77 	}
78 }
79 
80 /*
81  * User settable table: what characters are to be considered alphabetic?
82  * 256 bits. Locked by the console lock.
83  */
84 static u32 inwordLut[8]={
85   0x00000000, /* control chars     */
86   0x03FF0000, /* digits            */
87   0x87FFFFFE, /* uppercase and '_' */
88   0x07FFFFFE, /* lowercase         */
89   0x00000000,
90   0x00000000,
91   0xFF7FFFFF, /* latin-1 accented letters, not multiplication sign */
92   0xFF7FFFFF  /* latin-1 accented letters, not division sign */
93 };
94 
95 static inline int inword(const u16 c) {
96 	return c > 0xff || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
97 }
98 
99 /**
100  *	set loadlut		-	load the LUT table
101  *	@p: user table
102  *
103  *	Load the LUT table from user space. The caller must hold the console
104  *	lock. Make a temporary copy so a partial update doesn't make a mess.
105  */
106 int sel_loadlut(char __user *p)
107 {
108 	u32 tmplut[8];
109 	if (copy_from_user(tmplut, (u32 __user *)(p+4), 32))
110 		return -EFAULT;
111 	memcpy(inwordLut, tmplut, 32);
112 	return 0;
113 }
114 
115 /* does screen address p correspond to character at LH/RH edge of screen? */
116 static inline int atedge(const int p, int size_row)
117 {
118 	return (!(p % size_row)	|| !((p + 2) % size_row));
119 }
120 
121 /* constrain v such that v <= u */
122 static inline unsigned short limit(const unsigned short v, const unsigned short u)
123 {
124 	return (v > u) ? u : v;
125 }
126 
127 /* stores the char in UTF8 and returns the number of bytes used (1-3) */
128 static int store_utf8(u16 c, char *p)
129 {
130 	if (c < 0x80) {
131 		/*  0******* */
132 		p[0] = c;
133 		return 1;
134 	} else if (c < 0x800) {
135 		/* 110***** 10****** */
136 		p[0] = 0xc0 | (c >> 6);
137 		p[1] = 0x80 | (c & 0x3f);
138 		return 2;
139     	} else {
140 		/* 1110**** 10****** 10****** */
141 		p[0] = 0xe0 | (c >> 12);
142 		p[1] = 0x80 | ((c >> 6) & 0x3f);
143 		p[2] = 0x80 | (c & 0x3f);
144 		return 3;
145     	}
146 }
147 
148 /**
149  *	set_selection		- 	set the current selection.
150  *	@sel: user selection info
151  *	@tty: the console tty
152  *
153  *	Invoked by the ioctl handle for the vt layer.
154  *
155  *	The entire selection process is managed under the console_lock. It's
156  *	 a lot under the lock but its hardly a performance path
157  */
158 int set_selection(const struct tiocl_selection __user *sel, struct tty_struct *tty)
159 {
160 	struct vc_data *vc = vc_cons[fg_console].d;
161 	int sel_mode, new_sel_start, new_sel_end, spc;
162 	char *bp, *obp;
163 	int i, ps, pe, multiplier;
164 	u16 c;
165 	int mode;
166 
167 	poke_blanked_console();
168 
169 	{ unsigned short xs, ys, xe, ye;
170 
171 	  if (!access_ok(VERIFY_READ, sel, sizeof(*sel)))
172 		return -EFAULT;
173 	  __get_user(xs, &sel->xs);
174 	  __get_user(ys, &sel->ys);
175 	  __get_user(xe, &sel->xe);
176 	  __get_user(ye, &sel->ye);
177 	  __get_user(sel_mode, &sel->sel_mode);
178 	  xs--; ys--; xe--; ye--;
179 	  xs = limit(xs, vc->vc_cols - 1);
180 	  ys = limit(ys, vc->vc_rows - 1);
181 	  xe = limit(xe, vc->vc_cols - 1);
182 	  ye = limit(ye, vc->vc_rows - 1);
183 	  ps = ys * vc->vc_size_row + (xs << 1);
184 	  pe = ye * vc->vc_size_row + (xe << 1);
185 
186 	  if (sel_mode == TIOCL_SELCLEAR) {
187 	      /* useful for screendump without selection highlights */
188 	      clear_selection();
189 	      return 0;
190 	  }
191 
192 	  if (mouse_reporting() && (sel_mode & TIOCL_SELMOUSEREPORT)) {
193 	      mouse_report(tty, sel_mode & TIOCL_SELBUTTONMASK, xs, ys);
194 	      return 0;
195 	  }
196         }
197 
198 	if (ps > pe)	/* make sel_start <= sel_end */
199 	{
200 		int tmp = ps;
201 		ps = pe;
202 		pe = tmp;
203 	}
204 
205 	if (sel_cons != vc_cons[fg_console].d) {
206 		clear_selection();
207 		sel_cons = vc_cons[fg_console].d;
208 	}
209 	mode = vt_do_kdgkbmode(fg_console);
210 	if (mode == K_UNICODE)
211 		use_unicode = 1;
212 	else
213 		use_unicode = 0;
214 
215 	switch (sel_mode)
216 	{
217 		case TIOCL_SELCHAR:	/* character-by-character selection */
218 			new_sel_start = ps;
219 			new_sel_end = pe;
220 			break;
221 		case TIOCL_SELWORD:	/* word-by-word selection */
222 			spc = isspace(sel_pos(ps));
223 			for (new_sel_start = ps; ; ps -= 2)
224 			{
225 				if ((spc && !isspace(sel_pos(ps))) ||
226 				    (!spc && !inword(sel_pos(ps))))
227 					break;
228 				new_sel_start = ps;
229 				if (!(ps % vc->vc_size_row))
230 					break;
231 			}
232 			spc = isspace(sel_pos(pe));
233 			for (new_sel_end = pe; ; pe += 2)
234 			{
235 				if ((spc && !isspace(sel_pos(pe))) ||
236 				    (!spc && !inword(sel_pos(pe))))
237 					break;
238 				new_sel_end = pe;
239 				if (!((pe + 2) % vc->vc_size_row))
240 					break;
241 			}
242 			break;
243 		case TIOCL_SELLINE:	/* line-by-line selection */
244 			new_sel_start = ps - ps % vc->vc_size_row;
245 			new_sel_end = pe + vc->vc_size_row
246 				    - pe % vc->vc_size_row - 2;
247 			break;
248 		case TIOCL_SELPOINTER:
249 			highlight_pointer(pe);
250 			return 0;
251 		default:
252 			return -EINVAL;
253 	}
254 
255 	/* remove the pointer */
256 	highlight_pointer(-1);
257 
258 	/* select to end of line if on trailing space */
259 	if (new_sel_end > new_sel_start &&
260 		!atedge(new_sel_end, vc->vc_size_row) &&
261 		isspace(sel_pos(new_sel_end))) {
262 		for (pe = new_sel_end + 2; ; pe += 2)
263 			if (!isspace(sel_pos(pe)) ||
264 			    atedge(pe, vc->vc_size_row))
265 				break;
266 		if (isspace(sel_pos(pe)))
267 			new_sel_end = pe;
268 	}
269 	if (sel_start == -1)	/* no current selection */
270 		highlight(new_sel_start, new_sel_end);
271 	else if (new_sel_start == sel_start)
272 	{
273 		if (new_sel_end == sel_end)	/* no action required */
274 			return 0;
275 		else if (new_sel_end > sel_end)	/* extend to right */
276 			highlight(sel_end + 2, new_sel_end);
277 		else				/* contract from right */
278 			highlight(new_sel_end + 2, sel_end);
279 	}
280 	else if (new_sel_end == sel_end)
281 	{
282 		if (new_sel_start < sel_start)	/* extend to left */
283 			highlight(new_sel_start, sel_start - 2);
284 		else				/* contract from left */
285 			highlight(sel_start, new_sel_start - 2);
286 	}
287 	else	/* some other case; start selection from scratch */
288 	{
289 		clear_selection();
290 		highlight(new_sel_start, new_sel_end);
291 	}
292 	sel_start = new_sel_start;
293 	sel_end = new_sel_end;
294 
295 	/* Allocate a new buffer before freeing the old one ... */
296 	multiplier = use_unicode ? 3 : 1;  /* chars can take up to 3 bytes */
297 	bp = kmalloc(((sel_end-sel_start)/2+1)*multiplier, GFP_KERNEL);
298 	if (!bp) {
299 		printk(KERN_WARNING "selection: kmalloc() failed\n");
300 		clear_selection();
301 		return -ENOMEM;
302 	}
303 	kfree(sel_buffer);
304 	sel_buffer = bp;
305 
306 	obp = bp;
307 	for (i = sel_start; i <= sel_end; i += 2) {
308 		c = sel_pos(i);
309 		if (use_unicode)
310 			bp += store_utf8(c, bp);
311 		else
312 			*bp++ = c;
313 		if (!isspace(c))
314 			obp = bp;
315 		if (! ((i + 2) % vc->vc_size_row)) {
316 			/* strip trailing blanks from line and add newline,
317 			   unless non-space at end of line. */
318 			if (obp != bp) {
319 				bp = obp;
320 				*bp++ = '\r';
321 			}
322 			obp = bp;
323 		}
324 	}
325 	sel_buffer_lth = bp - sel_buffer;
326 	return 0;
327 }
328 
329 /* Insert the contents of the selection buffer into the
330  * queue of the tty associated with the current console.
331  * Invoked by ioctl().
332  *
333  * Locking: called without locks. Calls the ldisc wrongly with
334  * unsafe methods,
335  */
336 int paste_selection(struct tty_struct *tty)
337 {
338 	struct vc_data *vc = tty->driver_data;
339 	int	pasted = 0;
340 	unsigned int count;
341 	struct  tty_ldisc *ld;
342 	DECLARE_WAITQUEUE(wait, current);
343 
344 
345 	console_lock();
346 	poke_blanked_console();
347 	console_unlock();
348 
349 	/* FIXME: wtf is this supposed to achieve ? */
350 	ld = tty_ldisc_ref(tty);
351 	if (!ld)
352 		ld = tty_ldisc_ref_wait(tty);
353 
354 	/* FIXME: this is completely unsafe */
355 	add_wait_queue(&vc->paste_wait, &wait);
356 	while (sel_buffer && sel_buffer_lth > pasted) {
357 		set_current_state(TASK_INTERRUPTIBLE);
358 		if (test_bit(TTY_THROTTLED, &tty->flags)) {
359 			schedule();
360 			continue;
361 		}
362 		count = sel_buffer_lth - pasted;
363 		count = min(count, tty->receive_room);
364 		tty->ldisc->ops->receive_buf(tty, sel_buffer + pasted,
365 								NULL, count);
366 		pasted += count;
367 	}
368 	remove_wait_queue(&vc->paste_wait, &wait);
369 	__set_current_state(TASK_RUNNING);
370 
371 	tty_ldisc_deref(ld);
372 	return 0;
373 }
374