xref: /openbmc/linux/drivers/tty/vt/selection.c (revision 4a5f8ae5)
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  * 128 bits. Locked by the console lock.
84  */
85 static u32 inwordLut[]={
86   0x00000000, /* control chars     */
87   0x03FFE000, /* digits and "-./"  */
88   0x87FFFFFE, /* uppercase and '_' */
89   0x07FFFFFE, /* lowercase         */
90 };
91 
92 static inline int inword(const u16 c) {
93 	return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
94 }
95 
96 /**
97  *	set loadlut		-	load the LUT table
98  *	@p: user table
99  *
100  *	Load the LUT table from user space. The caller must hold the console
101  *	lock. Make a temporary copy so a partial update doesn't make a mess.
102  */
103 int sel_loadlut(char __user *p)
104 {
105 	u32 tmplut[ARRAY_SIZE(inwordLut)];
106 	if (copy_from_user(tmplut, (u32 __user *)(p+4), sizeof(inwordLut)))
107 		return -EFAULT;
108 	memcpy(inwordLut, tmplut, sizeof(inwordLut));
109 	return 0;
110 }
111 
112 /* does screen address p correspond to character at LH/RH edge of screen? */
113 static inline int atedge(const int p, int size_row)
114 {
115 	return (!(p % size_row)	|| !((p + 2) % size_row));
116 }
117 
118 /* constrain v such that v <= u */
119 static inline unsigned short limit(const unsigned short v, const unsigned short u)
120 {
121 	return (v > u) ? u : v;
122 }
123 
124 /* stores the char in UTF8 and returns the number of bytes used (1-3) */
125 static int store_utf8(u16 c, char *p)
126 {
127 	if (c < 0x80) {
128 		/*  0******* */
129 		p[0] = c;
130 		return 1;
131 	} else if (c < 0x800) {
132 		/* 110***** 10****** */
133 		p[0] = 0xc0 | (c >> 6);
134 		p[1] = 0x80 | (c & 0x3f);
135 		return 2;
136     	} else {
137 		/* 1110**** 10****** 10****** */
138 		p[0] = 0xe0 | (c >> 12);
139 		p[1] = 0x80 | ((c >> 6) & 0x3f);
140 		p[2] = 0x80 | (c & 0x3f);
141 		return 3;
142     	}
143 }
144 
145 /**
146  *	set_selection		- 	set the current selection.
147  *	@sel: user selection info
148  *	@tty: the console tty
149  *
150  *	Invoked by the ioctl handle for the vt layer.
151  *
152  *	The entire selection process is managed under the console_lock. It's
153  *	 a lot under the lock but its hardly a performance path
154  */
155 int set_selection(const struct tiocl_selection __user *sel, struct tty_struct *tty)
156 {
157 	struct vc_data *vc = vc_cons[fg_console].d;
158 	int sel_mode, new_sel_start, new_sel_end, spc;
159 	char *bp, *obp;
160 	int i, ps, pe, multiplier;
161 	u16 c;
162 	int mode;
163 
164 	poke_blanked_console();
165 
166 	{ unsigned short xs, ys, xe, ye;
167 
168 	  if (!access_ok(VERIFY_READ, sel, sizeof(*sel)))
169 		return -EFAULT;
170 	  __get_user(xs, &sel->xs);
171 	  __get_user(ys, &sel->ys);
172 	  __get_user(xe, &sel->xe);
173 	  __get_user(ye, &sel->ye);
174 	  __get_user(sel_mode, &sel->sel_mode);
175 	  xs--; ys--; xe--; ye--;
176 	  xs = limit(xs, vc->vc_cols - 1);
177 	  ys = limit(ys, vc->vc_rows - 1);
178 	  xe = limit(xe, vc->vc_cols - 1);
179 	  ye = limit(ye, vc->vc_rows - 1);
180 	  ps = ys * vc->vc_size_row + (xs << 1);
181 	  pe = ye * vc->vc_size_row + (xe << 1);
182 
183 	  if (sel_mode == TIOCL_SELCLEAR) {
184 	      /* useful for screendump without selection highlights */
185 	      clear_selection();
186 	      return 0;
187 	  }
188 
189 	  if (mouse_reporting() && (sel_mode & TIOCL_SELMOUSEREPORT)) {
190 	      mouse_report(tty, sel_mode & TIOCL_SELBUTTONMASK, xs, ys);
191 	      return 0;
192 	  }
193         }
194 
195 	if (ps > pe)	/* make sel_start <= sel_end */
196 	{
197 		int tmp = ps;
198 		ps = pe;
199 		pe = tmp;
200 	}
201 
202 	if (sel_cons != vc_cons[fg_console].d) {
203 		clear_selection();
204 		sel_cons = vc_cons[fg_console].d;
205 	}
206 	mode = vt_do_kdgkbmode(fg_console);
207 	if (mode == K_UNICODE)
208 		use_unicode = 1;
209 	else
210 		use_unicode = 0;
211 
212 	switch (sel_mode)
213 	{
214 		case TIOCL_SELCHAR:	/* character-by-character selection */
215 			new_sel_start = ps;
216 			new_sel_end = pe;
217 			break;
218 		case TIOCL_SELWORD:	/* word-by-word selection */
219 			spc = isspace(sel_pos(ps));
220 			for (new_sel_start = ps; ; ps -= 2)
221 			{
222 				if ((spc && !isspace(sel_pos(ps))) ||
223 				    (!spc && !inword(sel_pos(ps))))
224 					break;
225 				new_sel_start = ps;
226 				if (!(ps % vc->vc_size_row))
227 					break;
228 			}
229 			spc = isspace(sel_pos(pe));
230 			for (new_sel_end = pe; ; pe += 2)
231 			{
232 				if ((spc && !isspace(sel_pos(pe))) ||
233 				    (!spc && !inword(sel_pos(pe))))
234 					break;
235 				new_sel_end = pe;
236 				if (!((pe + 2) % vc->vc_size_row))
237 					break;
238 			}
239 			break;
240 		case TIOCL_SELLINE:	/* line-by-line selection */
241 			new_sel_start = ps - ps % vc->vc_size_row;
242 			new_sel_end = pe + vc->vc_size_row
243 				    - pe % vc->vc_size_row - 2;
244 			break;
245 		case TIOCL_SELPOINTER:
246 			highlight_pointer(pe);
247 			return 0;
248 		default:
249 			return -EINVAL;
250 	}
251 
252 	/* remove the pointer */
253 	highlight_pointer(-1);
254 
255 	/* select to end of line if on trailing space */
256 	if (new_sel_end > new_sel_start &&
257 		!atedge(new_sel_end, vc->vc_size_row) &&
258 		isspace(sel_pos(new_sel_end))) {
259 		for (pe = new_sel_end + 2; ; pe += 2)
260 			if (!isspace(sel_pos(pe)) ||
261 			    atedge(pe, vc->vc_size_row))
262 				break;
263 		if (isspace(sel_pos(pe)))
264 			new_sel_end = pe;
265 	}
266 	if (sel_start == -1)	/* no current selection */
267 		highlight(new_sel_start, new_sel_end);
268 	else if (new_sel_start == sel_start)
269 	{
270 		if (new_sel_end == sel_end)	/* no action required */
271 			return 0;
272 		else if (new_sel_end > sel_end)	/* extend to right */
273 			highlight(sel_end + 2, new_sel_end);
274 		else				/* contract from right */
275 			highlight(new_sel_end + 2, sel_end);
276 	}
277 	else if (new_sel_end == sel_end)
278 	{
279 		if (new_sel_start < sel_start)	/* extend to left */
280 			highlight(new_sel_start, sel_start - 2);
281 		else				/* contract from left */
282 			highlight(sel_start, new_sel_start - 2);
283 	}
284 	else	/* some other case; start selection from scratch */
285 	{
286 		clear_selection();
287 		highlight(new_sel_start, new_sel_end);
288 	}
289 	sel_start = new_sel_start;
290 	sel_end = new_sel_end;
291 
292 	/* Allocate a new buffer before freeing the old one ... */
293 	multiplier = use_unicode ? 3 : 1;  /* chars can take up to 3 bytes */
294 	bp = kmalloc(((sel_end-sel_start)/2+1)*multiplier, GFP_KERNEL);
295 	if (!bp) {
296 		printk(KERN_WARNING "selection: kmalloc() failed\n");
297 		clear_selection();
298 		return -ENOMEM;
299 	}
300 	kfree(sel_buffer);
301 	sel_buffer = bp;
302 
303 	obp = bp;
304 	for (i = sel_start; i <= sel_end; i += 2) {
305 		c = sel_pos(i);
306 		if (use_unicode)
307 			bp += store_utf8(c, bp);
308 		else
309 			*bp++ = c;
310 		if (!isspace(c))
311 			obp = bp;
312 		if (! ((i + 2) % vc->vc_size_row)) {
313 			/* strip trailing blanks from line and add newline,
314 			   unless non-space at end of line. */
315 			if (obp != bp) {
316 				bp = obp;
317 				*bp++ = '\r';
318 			}
319 			obp = bp;
320 		}
321 	}
322 	sel_buffer_lth = bp - sel_buffer;
323 	return 0;
324 }
325 
326 /* Insert the contents of the selection buffer into the
327  * queue of the tty associated with the current console.
328  * Invoked by ioctl().
329  *
330  * Locking: called without locks. Calls the ldisc wrongly with
331  * unsafe methods,
332  */
333 int paste_selection(struct tty_struct *tty)
334 {
335 	struct vc_data *vc = tty->driver_data;
336 	int	pasted = 0;
337 	unsigned int count;
338 	struct  tty_ldisc *ld;
339 	DECLARE_WAITQUEUE(wait, current);
340 
341 	console_lock();
342 	poke_blanked_console();
343 	console_unlock();
344 
345 	ld = tty_ldisc_ref_wait(tty);
346 	if (!ld)
347 		return -EIO;	/* ldisc was hung up */
348 	tty_buffer_lock_exclusive(&vc->port);
349 
350 	add_wait_queue(&vc->paste_wait, &wait);
351 	while (sel_buffer && sel_buffer_lth > pasted) {
352 		set_current_state(TASK_INTERRUPTIBLE);
353 		if (tty_throttled(tty)) {
354 			schedule();
355 			continue;
356 		}
357 		__set_current_state(TASK_RUNNING);
358 		count = sel_buffer_lth - pasted;
359 		count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
360 					      count);
361 		pasted += count;
362 	}
363 	remove_wait_queue(&vc->paste_wait, &wait);
364 	__set_current_state(TASK_RUNNING);
365 
366 	tty_buffer_unlock_exclusive(&vc->port);
367 	tty_ldisc_deref(ld);
368 	return 0;
369 }
370