xref: /freebsd/sys/dev/vt/vt_buf.c (revision 193d9e768ba63fcfb187cfd17f461f7d41345048)
1 /*-
2  * Copyright (c) 2009, 2013 The FreeBSD Foundation
3  * All rights reserved.
4  *
5  * This software was developed by Ed Schouten under sponsorship from the
6  * FreeBSD Foundation.
7  *
8  * Portions of this software were developed by Oleksandr Rybalko
9  * under sponsorship from the FreeBSD Foundation.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include <sys/param.h>
37 #include <sys/kernel.h>
38 #include <sys/lock.h>
39 #include <sys/malloc.h>
40 #include <sys/mutex.h>
41 #include <sys/reboot.h>
42 #include <sys/systm.h>
43 
44 #include <dev/vt/vt.h>
45 
46 static MALLOC_DEFINE(M_VTBUF, "vtbuf", "vt buffer");
47 
48 #define	VTBUF_LOCK(vb)		mtx_lock_spin(&(vb)->vb_lock)
49 #define	VTBUF_UNLOCK(vb)	mtx_unlock_spin(&(vb)->vb_lock)
50 
51 #define POS_INDEX(c, r) (((r) << 12) + (c))
52 #define	POS_COPY(d, s)	do {	\
53 	(d).tp_col = (s).tp_col;	\
54 	(d).tp_row = (s).tp_row;	\
55 } while (0)
56 
57 #ifndef SC_NO_CUTPASTE
58 static int vtbuf_htw(const struct vt_buf *vb, int row);
59 static int vtbuf_wth(const struct vt_buf *vb, int row);
60 static int vtbuf_in_this_range(int begin, int test, int end, int sz);
61 #endif
62 
63 /*
64  * line4
65  * line5 <--- curroffset (terminal output to that line)
66  * line0
67  * line1                  <--- roffset (history display from that point)
68  * line2
69  * line3
70  */
71 int
72 vthistory_seek(struct vt_buf *vb, int offset, int whence)
73 {
74 	int diff, top, bottom, roffset;
75 
76 	/* No scrolling if not enabled. */
77 	if ((vb->vb_flags & VBF_SCROLL) == 0) {
78 		if (vb->vb_roffset != vb->vb_curroffset) {
79 			vb->vb_roffset = vb->vb_curroffset;
80 			return (0xffff);
81 		}
82 		return (0); /* No changes */
83 	}
84 
85 	/* "top" may be a negative integer. */
86 	bottom = vb->vb_curroffset;
87 	top = (vb->vb_flags & VBF_HISTORY_FULL) ?
88 	    bottom + vb->vb_scr_size.tp_row - vb->vb_history_size :
89 	    0;
90 
91 	roffset = 0; /* Make gcc happy. */
92 	switch (whence) {
93 	case VHS_SET:
94 		if (offset < 0)
95 			offset = 0;
96 		roffset = top + offset;
97 		break;
98 	case VHS_CUR:
99 		/*
100 		 * Operate on copy of offset value, since it temporary
101 		 * can be bigger than amount of rows in buffer.
102 		 */
103 		roffset = vb->vb_roffset;
104 		if (roffset >= bottom + vb->vb_scr_size.tp_row)
105 			roffset -= vb->vb_history_size;
106 
107 		roffset += offset;
108 		roffset = MAX(roffset, top);
109 		roffset = MIN(roffset, bottom);
110 
111 		if (roffset < 0)
112 			roffset = vb->vb_history_size + roffset;
113 
114 		break;
115 	case VHS_END:
116 		/* Go to current offset. */
117 		roffset = vb->vb_curroffset;
118 		break;
119 	}
120 
121 	diff = vb->vb_roffset != roffset;
122 	vb->vb_roffset = roffset;
123 
124 	return (diff);
125 }
126 
127 void
128 vthistory_addlines(struct vt_buf *vb, int offset)
129 {
130 #ifndef SC_NO_CUTPASTE
131 	int cur, sz;
132 #endif
133 
134 	vb->vb_curroffset += offset;
135 	if (vb->vb_curroffset < 0)
136 		vb->vb_curroffset = 0;
137 	if (vb->vb_curroffset + vb->vb_scr_size.tp_row >= vb->vb_history_size)
138 		vb->vb_flags |= VBF_HISTORY_FULL;
139 	vb->vb_curroffset %= vb->vb_history_size;
140 	if ((vb->vb_flags & VBF_SCROLL) == 0) {
141 		vb->vb_roffset = vb->vb_curroffset;
142 	}
143 
144 #ifndef SC_NO_CUTPASTE
145 	sz = vb->vb_history_size;
146 	cur = vb->vb_roffset + vb->vb_scr_size.tp_row + sz - 1;
147 	if (vtbuf_in_this_range(cur, vb->vb_mark_start.tp_row, cur + offset, sz) ||
148 	    vtbuf_in_this_range(cur, vb->vb_mark_end.tp_row, cur + offset, sz)) {
149 		/* clear screen selection */
150 		vb->vb_mark_start.tp_row = vb->vb_mark_end.tp_row;
151 		vb->vb_mark_start.tp_col = vb->vb_mark_end.tp_col;
152 	}
153 #endif
154 }
155 
156 void
157 vthistory_getpos(const struct vt_buf *vb, unsigned int *offset)
158 {
159 
160 	*offset = vb->vb_roffset;
161 }
162 
163 #ifndef SC_NO_CUTPASTE	/* Only mouse support use it now. */
164 /* Translate history row to current view row number. */
165 static int
166 vtbuf_htw(const struct vt_buf *vb, int row)
167 {
168 
169 	/*
170 	 * total 1000 rows.
171 	 * History offset	roffset	winrow
172 	 *	205		200	((205 - 200 + 1000) % 1000) = 5
173 	 *	90		990	((90 - 990 + 1000) % 1000) = 100
174 	 */
175 	return ((row - vb->vb_roffset + vb->vb_history_size) %
176 	    vb->vb_history_size);
177 }
178 
179 /* Translate current view row number to history row. */
180 static int
181 vtbuf_wth(const struct vt_buf *vb, int row)
182 {
183 
184 	return ((vb->vb_roffset + row) % vb->vb_history_size);
185 }
186 
187 /*
188  * Test if an index in a circular buffer is within a range.
189  *
190  * begin - start index
191  * end - end index
192  * test - test index
193  * sz - size of circular buffer when it turns over
194  */
195 static int
196 vtbuf_in_this_range(int begin, int test, int end, int sz)
197 {
198 
199 	begin %= sz;
200 	end %= sz;
201 
202 	/* check for inversion */
203 	if (begin > end)
204 		return (test >= begin || test < end);
205 	else
206 		return (test >= begin && test < end);
207 }
208 #endif
209 
210 int
211 vtbuf_iscursor(const struct vt_buf *vb, int row, int col)
212 {
213 #ifndef SC_NO_CUTPASTE
214 	int sc, sr, sz, ec, er, tmp;
215 #endif
216 
217 	if ((vb->vb_flags & (VBF_CURSOR|VBF_SCROLL)) == VBF_CURSOR &&
218 	    (vb->vb_cursor.tp_row == row) && (vb->vb_cursor.tp_col == col))
219 		return (1);
220 
221 #ifndef SC_NO_CUTPASTE
222 	/* Mark cut/paste region. */
223 	if (vb->vb_mark_start.tp_col == vb->vb_mark_end.tp_col &&
224 	    vb->vb_mark_start.tp_row == vb->vb_mark_end.tp_row)
225 		return (0);
226 
227 	sc = vb->vb_mark_start.tp_col;
228 	sr = vb->vb_mark_start.tp_row;
229 	ec = vb->vb_mark_end.tp_col;
230 	er = vb->vb_mark_end.tp_row;
231 
232 	/*
233 	 * Information about if the selection was made bottom-top or
234 	 * top-bottom is lost due to modulo arithmetics and needs to
235 	 * be recovered:
236 	 */
237 	sz = vb->vb_history_size;
238 	tmp = (sz + er - sr) % sz;
239 	row = vtbuf_wth(vb, row);
240 
241 	/* Swap start and end if start > end */
242 	if ((2 * tmp) > sz || (tmp == 0 && sc > ec)) {
243 		tmp = sc; sc = ec; ec = tmp;
244 		tmp = sr; sr = er; er = tmp;
245 	}
246 
247 	if (vtbuf_in_this_range(POS_INDEX(sc, sr), POS_INDEX(col, row),
248 	    POS_INDEX(ec, er), POS_INDEX(0, sz)))
249 		return (1);
250 #endif
251 
252 	return (0);
253 }
254 
255 static inline void
256 vtbuf_dirty_locked(struct vt_buf *vb, const term_rect_t *area)
257 {
258 
259 	if (vb->vb_dirtyrect.tr_begin.tp_row > area->tr_begin.tp_row)
260 		vb->vb_dirtyrect.tr_begin.tp_row = area->tr_begin.tp_row;
261 	if (vb->vb_dirtyrect.tr_begin.tp_col > area->tr_begin.tp_col)
262 		vb->vb_dirtyrect.tr_begin.tp_col = area->tr_begin.tp_col;
263 	if (vb->vb_dirtyrect.tr_end.tp_row < area->tr_end.tp_row)
264 		vb->vb_dirtyrect.tr_end.tp_row = area->tr_end.tp_row;
265 	if (vb->vb_dirtyrect.tr_end.tp_col < area->tr_end.tp_col)
266 		vb->vb_dirtyrect.tr_end.tp_col = area->tr_end.tp_col;
267 }
268 
269 void
270 vtbuf_dirty(struct vt_buf *vb, const term_rect_t *area)
271 {
272 
273 	VTBUF_LOCK(vb);
274 	vtbuf_dirty_locked(vb, area);
275 	VTBUF_UNLOCK(vb);
276 }
277 
278 static inline void
279 vtbuf_dirty_cell_locked(struct vt_buf *vb, const term_pos_t *p)
280 {
281 	term_rect_t area;
282 
283 	area.tr_begin = *p;
284 	area.tr_end.tp_row = p->tp_row + 1;
285 	area.tr_end.tp_col = p->tp_col + 1;
286 	vtbuf_dirty_locked(vb, &area);
287 }
288 
289 static void
290 vtbuf_make_undirty(struct vt_buf *vb)
291 {
292 
293 	vb->vb_dirtyrect.tr_begin = vb->vb_scr_size;
294 	vb->vb_dirtyrect.tr_end.tp_row = vb->vb_dirtyrect.tr_end.tp_col = 0;
295 }
296 
297 void
298 vtbuf_undirty(struct vt_buf *vb, term_rect_t *r)
299 {
300 
301 	VTBUF_LOCK(vb);
302 	*r = vb->vb_dirtyrect;
303 	vtbuf_make_undirty(vb);
304 	VTBUF_UNLOCK(vb);
305 }
306 
307 void
308 vtbuf_copy(struct vt_buf *vb, const term_rect_t *r, const term_pos_t *p2)
309 {
310 	const term_pos_t *p1 = &r->tr_begin;
311 	term_rect_t area;
312 	unsigned int rows, cols;
313 	int pr, rdiff;
314 
315 	KASSERT(r->tr_begin.tp_row < vb->vb_scr_size.tp_row,
316 	    ("vtbuf_copy begin.tp_row %d must be less than screen width %d",
317 		r->tr_begin.tp_row, vb->vb_scr_size.tp_row));
318 	KASSERT(r->tr_begin.tp_col < vb->vb_scr_size.tp_col,
319 	    ("vtbuf_copy begin.tp_col %d must be less than screen height %d",
320 		r->tr_begin.tp_col, vb->vb_scr_size.tp_col));
321 
322 	KASSERT(r->tr_end.tp_row <= vb->vb_scr_size.tp_row,
323 	    ("vtbuf_copy end.tp_row %d must be less than screen width %d",
324 		r->tr_end.tp_row, vb->vb_scr_size.tp_row));
325 	KASSERT(r->tr_end.tp_col <= vb->vb_scr_size.tp_col,
326 	    ("vtbuf_copy end.tp_col %d must be less than screen height %d",
327 		r->tr_end.tp_col, vb->vb_scr_size.tp_col));
328 
329 	KASSERT(p2->tp_row < vb->vb_scr_size.tp_row,
330 	    ("vtbuf_copy tp_row %d must be less than screen width %d",
331 		p2->tp_row, vb->vb_scr_size.tp_row));
332 	KASSERT(p2->tp_col < vb->vb_scr_size.tp_col,
333 	    ("vtbuf_copy tp_col %d must be less than screen height %d",
334 		p2->tp_col, vb->vb_scr_size.tp_col));
335 
336 	rows = r->tr_end.tp_row - r->tr_begin.tp_row;
337 	rdiff = r->tr_begin.tp_row - p2->tp_row;
338 	cols = r->tr_end.tp_col - r->tr_begin.tp_col;
339 	if (r->tr_begin.tp_row > p2->tp_row && r->tr_begin.tp_col == 0 &&
340 	    r->tr_end.tp_col == vb->vb_scr_size.tp_col && /* Full row. */
341 	    (rows + rdiff) == vb->vb_scr_size.tp_row && /* Whole screen. */
342 	    rdiff > 0) { /* Only forward direction. Do not eat history. */
343 		vthistory_addlines(vb, rdiff);
344 	} else if (p2->tp_row < p1->tp_row) {
345 		/* Handle overlapping copies of line segments. */
346 		/* Move data up. */
347 		for (pr = 0; pr < rows; pr++)
348 			memmove(
349 			    &VTBUF_FIELD(vb, p2->tp_row + pr, p2->tp_col),
350 			    &VTBUF_FIELD(vb, p1->tp_row + pr, p1->tp_col),
351 			    cols * sizeof(term_char_t));
352 	} else {
353 		/* Move data down. */
354 		for (pr = rows - 1; pr >= 0; pr--)
355 			memmove(
356 			    &VTBUF_FIELD(vb, p2->tp_row + pr, p2->tp_col),
357 			    &VTBUF_FIELD(vb, p1->tp_row + pr, p1->tp_col),
358 			    cols * sizeof(term_char_t));
359 	}
360 
361 	area.tr_begin = *p2;
362 	area.tr_end.tp_row = MIN(p2->tp_row + rows, vb->vb_scr_size.tp_row);
363 	area.tr_end.tp_col = MIN(p2->tp_col + cols, vb->vb_scr_size.tp_col);
364 	vtbuf_dirty(vb, &area);
365 }
366 
367 static void
368 vtbuf_fill(struct vt_buf *vb, const term_rect_t *r, term_char_t c)
369 {
370 	unsigned int pr, pc;
371 	term_char_t *row;
372 
373 	for (pr = r->tr_begin.tp_row; pr < r->tr_end.tp_row; pr++) {
374 		row = vb->vb_rows[(vb->vb_curroffset + pr) %
375 		    VTBUF_MAX_HEIGHT(vb)];
376 		for (pc = r->tr_begin.tp_col; pc < r->tr_end.tp_col; pc++) {
377 			row[pc] = c;
378 		}
379 	}
380 }
381 
382 void
383 vtbuf_fill_locked(struct vt_buf *vb, const term_rect_t *r, term_char_t c)
384 {
385 	KASSERT(r->tr_begin.tp_row < vb->vb_scr_size.tp_row,
386 	    ("vtbuf_fill_locked begin.tp_row %d must be < screen height %d",
387 		r->tr_begin.tp_row, vb->vb_scr_size.tp_row));
388 	KASSERT(r->tr_begin.tp_col < vb->vb_scr_size.tp_col,
389 	    ("vtbuf_fill_locked begin.tp_col %d must be < screen width %d",
390 		r->tr_begin.tp_col, vb->vb_scr_size.tp_col));
391 
392 	KASSERT(r->tr_end.tp_row <= vb->vb_scr_size.tp_row,
393 	    ("vtbuf_fill_locked end.tp_row %d must be <= screen height %d",
394 		r->tr_end.tp_row, vb->vb_scr_size.tp_row));
395 	KASSERT(r->tr_end.tp_col <= vb->vb_scr_size.tp_col,
396 	    ("vtbuf_fill_locked end.tp_col %d must be <= screen width %d",
397 		r->tr_end.tp_col, vb->vb_scr_size.tp_col));
398 
399 	VTBUF_LOCK(vb);
400 	vtbuf_fill(vb, r, c);
401 	vtbuf_dirty_locked(vb, r);
402 	VTBUF_UNLOCK(vb);
403 }
404 
405 static void
406 vtbuf_init_rows(struct vt_buf *vb)
407 {
408 	int r;
409 
410 	vb->vb_history_size = MAX(vb->vb_history_size, vb->vb_scr_size.tp_row);
411 
412 	for (r = 0; r < vb->vb_history_size; r++)
413 		vb->vb_rows[r] = &vb->vb_buffer[r * vb->vb_scr_size.tp_col];
414 }
415 
416 void
417 vtbuf_init_early(struct vt_buf *vb)
418 {
419 	term_rect_t rect;
420 
421 	vb->vb_flags |= VBF_CURSOR;
422 	vb->vb_roffset = 0;
423 	vb->vb_curroffset = 0;
424 	vb->vb_mark_start.tp_row = 0;
425 	vb->vb_mark_start.tp_col = 0;
426 	vb->vb_mark_end.tp_row = 0;
427 	vb->vb_mark_end.tp_col = 0;
428 
429 	vtbuf_init_rows(vb);
430 	rect.tr_begin.tp_row = rect.tr_begin.tp_col = 0;
431 	rect.tr_end.tp_col = vb->vb_scr_size.tp_col;
432 	rect.tr_end.tp_row = vb->vb_history_size;
433 	vtbuf_fill(vb, &rect, VTBUF_SPACE_CHAR(TERMINAL_NORM_ATTR));
434 	vtbuf_make_undirty(vb);
435 	if ((vb->vb_flags & VBF_MTX_INIT) == 0) {
436 		mtx_init(&vb->vb_lock, "vtbuf", NULL, MTX_SPIN);
437 		vb->vb_flags |= VBF_MTX_INIT;
438 	}
439 }
440 
441 void
442 vtbuf_init(struct vt_buf *vb, const term_pos_t *p)
443 {
444 	int sz;
445 
446 	vb->vb_scr_size = *p;
447 	vb->vb_history_size = VBF_DEFAULT_HISTORY_SIZE;
448 
449 	if ((vb->vb_flags & VBF_STATIC) == 0) {
450 		sz = vb->vb_history_size * p->tp_col * sizeof(term_char_t);
451 		vb->vb_buffer = malloc(sz, M_VTBUF, M_WAITOK | M_ZERO);
452 
453 		sz = vb->vb_history_size * sizeof(term_char_t *);
454 		vb->vb_rows = malloc(sz, M_VTBUF, M_WAITOK | M_ZERO);
455 	}
456 
457 	vtbuf_init_early(vb);
458 }
459 
460 void
461 vtbuf_sethistory_size(struct vt_buf *vb, int size)
462 {
463 	term_pos_t p;
464 
465 	/* With same size */
466 	p.tp_row = vb->vb_scr_size.tp_row;
467 	p.tp_col = vb->vb_scr_size.tp_col;
468 	vtbuf_grow(vb, &p, size);
469 }
470 
471 void
472 vtbuf_grow(struct vt_buf *vb, const term_pos_t *p, unsigned int history_size)
473 {
474 	term_char_t *old, *new, **rows, **oldrows, **copyrows, *row, *oldrow;
475 	int bufsize, rowssize, w, h, c, r, history_was_full;
476 	unsigned int old_history_size;
477 	term_rect_t rect;
478 
479 	history_size = MAX(history_size, p->tp_row);
480 
481 	/* Allocate new buffer. */
482 	bufsize = history_size * p->tp_col * sizeof(term_char_t);
483 	new = malloc(bufsize, M_VTBUF, M_WAITOK | M_ZERO);
484 	rowssize = history_size * sizeof(term_pos_t *);
485 	rows = malloc(rowssize, M_VTBUF, M_WAITOK | M_ZERO);
486 
487 	/* Toggle it. */
488 	VTBUF_LOCK(vb);
489 	old = vb->vb_flags & VBF_STATIC ? NULL : vb->vb_buffer;
490 	oldrows = vb->vb_flags & VBF_STATIC ? NULL : vb->vb_rows;
491 	copyrows = vb->vb_rows;
492 
493 	w = vb->vb_scr_size.tp_col;
494 	h = vb->vb_scr_size.tp_row;
495 	old_history_size = vb->vb_history_size;
496 	history_was_full = vb->vb_flags & VBF_HISTORY_FULL;
497 
498 	vb->vb_history_size = history_size;
499 	vb->vb_buffer = new;
500 	vb->vb_rows = rows;
501 	vb->vb_flags &= ~VBF_STATIC;
502 	vb->vb_scr_size = *p;
503 	vtbuf_init_rows(vb);
504 
505 	/* Copy history and fill extra space if needed. */
506 	if (history_size > old_history_size) {
507 		/*
508 		 * Copy rows to the new buffer. The first row in the history
509 		 * is back to index 0, ie. the new buffer doesn't cycle.
510 		 *
511 		 * The rest of the new buffer is initialized with blank
512 		 * content.
513 		 */
514 		for (r = 0; r < old_history_size; r ++) {
515 			row = rows[r];
516 
517 			/* Compute the corresponding row in the old buffer. */
518 			if (history_was_full)
519 				/*
520 				 * The buffer is full, the "top" row is
521 				 * the one just after the viewable area
522 				 * (curroffset + viewable height) in the
523 				 * cycling buffer. The corresponding row
524 				 * is computed from this top row.
525 				 */
526 				oldrow = copyrows[
527 				    (vb->vb_curroffset + h + r) %
528 				    old_history_size];
529 			else
530 				/*
531 				 * The buffer is not full, therefore,
532 				 * we didn't cycle already. The
533 				 * corresponding rows are the same in
534 				 * both buffers.
535 				 */
536 				oldrow = copyrows[r];
537 
538 			memmove(row, oldrow,
539 			    MIN(p->tp_col, w) * sizeof(term_char_t));
540 
541 			/*
542 			 * XXX VTBUF_SPACE_CHAR(TERMINAL_NORM_ATTR) will
543 			 * extended lines of kernel text using the wrong
544 			 * background color.
545 			 */
546 			for (c = MIN(p->tp_col, w); c < p->tp_col; c++) {
547 				row[c] = VTBUF_SPACE_CHAR(TERMINAL_NORM_ATTR);
548 			}
549 		}
550 
551 		/* Fill remaining rows. */
552 		rect.tr_begin.tp_col = 0;
553 		rect.tr_begin.tp_row = old_history_size;
554 		rect.tr_end.tp_col = p->tp_col;
555 		rect.tr_end.tp_row = p->tp_row;
556 		vtbuf_fill(vb, &rect, VTBUF_SPACE_CHAR(TERMINAL_NORM_ATTR));
557 
558 		vb->vb_flags &= ~VBF_HISTORY_FULL;
559 	} else {
560 		/*
561 		 * Copy rows to the new buffer. The first row in the history
562 		 * is back to index 0, ie. the new buffer doesn't cycle.
563 		 *
564 		 * (old_history_size - history_size) lines of history are
565 		 * dropped.
566 		 */
567 		for (r = 0; r < history_size; r ++) {
568 			row = rows[r];
569 
570 			/*
571 			 * Compute the corresponding row in the old buffer.
572 			 *
573 			 * See the equivalent if{} block above for an
574 			 * explanation.
575 			 */
576 			if (history_was_full)
577 				oldrow = copyrows[
578 				    (vb->vb_curroffset + h + r +
579 				     (old_history_size - history_size)) %
580 				    old_history_size];
581 			else
582 				oldrow = copyrows[
583 				    (r + (old_history_size - history_size)) %
584 				    old_history_size];
585 
586 			memmove(row, oldrow,
587 			    MIN(p->tp_col, w) * sizeof(term_char_t));
588 
589 			/*
590 			 * XXX VTBUF_SPACE_CHAR(TERMINAL_NORM_ATTR) will
591 			 * extended lines of kernel text using the wrong
592 			 * background color.
593 			 */
594 			for (c = MIN(p->tp_col, w); c < p->tp_col; c++) {
595 				row[c] = VTBUF_SPACE_CHAR(TERMINAL_NORM_ATTR);
596 			}
597 		}
598 
599 		if (!history_was_full &&
600 		    (vb->vb_curroffset + h) >= history_size)
601 			vb->vb_flags |= VBF_HISTORY_FULL;
602 	}
603 
604 	/*
605 	 * If the screen is already filled (there are non-visible lines
606 	 * above the current viewable area), adjust curroffset to the
607 	 * new viewable area.
608 	 */
609 	if (!history_was_full && vb->vb_curroffset > 0) {
610 		vb->vb_curroffset = vb->vb_curroffset + h - p->tp_row;
611 		if (vb->vb_curroffset < 0)
612 			vb->vb_curroffset += vb->vb_history_size;
613 		vb->vb_curroffset %= vb->vb_history_size;
614 		vb->vb_roffset = vb->vb_curroffset;
615 	}
616 
617 	/* Adjust cursor position. */
618 	if (vb->vb_cursor.tp_col > p->tp_col - 1)
619 		/*
620 		 * Move cursor to the last column, in case its previous
621 		 * position is outside of the new screen area.
622 		 */
623 		vb->vb_cursor.tp_col = p->tp_col - 1;
624 
625 	if (vb->vb_curroffset > 0 || vb->vb_cursor.tp_row > p->tp_row - 1)
626 		/* Move cursor to the last line on the screen. */
627 		vb->vb_cursor.tp_row = p->tp_row - 1;
628 
629 	vtbuf_make_undirty(vb);
630 	VTBUF_UNLOCK(vb);
631 
632 	/* Deallocate old buffer. */
633 	free(old, M_VTBUF);
634 	free(oldrows, M_VTBUF);
635 }
636 
637 void
638 vtbuf_putchar(struct vt_buf *vb, const term_pos_t *p, term_char_t c)
639 {
640 	term_char_t *row;
641 
642 	KASSERT(p->tp_row < vb->vb_scr_size.tp_row,
643 	    ("vtbuf_putchar tp_row %d must be less than screen width %d",
644 		p->tp_row, vb->vb_scr_size.tp_row));
645 	KASSERT(p->tp_col < vb->vb_scr_size.tp_col,
646 	    ("vtbuf_putchar tp_col %d must be less than screen height %d",
647 		p->tp_col, vb->vb_scr_size.tp_col));
648 
649 	row = vb->vb_rows[(vb->vb_curroffset + p->tp_row) %
650 	    VTBUF_MAX_HEIGHT(vb)];
651 	if (row[p->tp_col] != c) {
652 		VTBUF_LOCK(vb);
653 		row[p->tp_col] = c;
654 		vtbuf_dirty_cell_locked(vb, p);
655 		VTBUF_UNLOCK(vb);
656 	}
657 }
658 
659 void
660 vtbuf_cursor_position(struct vt_buf *vb, const term_pos_t *p)
661 {
662 
663 	if (vb->vb_flags & VBF_CURSOR) {
664 		VTBUF_LOCK(vb);
665 		vtbuf_dirty_cell_locked(vb, &vb->vb_cursor);
666 		vb->vb_cursor = *p;
667 		vtbuf_dirty_cell_locked(vb, &vb->vb_cursor);
668 		VTBUF_UNLOCK(vb);
669 	} else {
670 		vb->vb_cursor = *p;
671 	}
672 }
673 
674 #ifndef SC_NO_CUTPASTE
675 static void
676 vtbuf_flush_mark(struct vt_buf *vb)
677 {
678 	term_rect_t area;
679 	int s, e;
680 
681 	/* Notify renderer to update marked region. */
682 	if ((vb->vb_mark_start.tp_col != vb->vb_mark_end.tp_col) ||
683 	    (vb->vb_mark_start.tp_row != vb->vb_mark_end.tp_row)) {
684 
685 		s = vtbuf_htw(vb, vb->vb_mark_start.tp_row);
686 		e = vtbuf_htw(vb, vb->vb_mark_end.tp_row);
687 
688 		area.tr_begin.tp_col = 0;
689 		area.tr_begin.tp_row = MIN(s, e);
690 
691 		area.tr_end.tp_col = vb->vb_scr_size.tp_col;
692 		area.tr_end.tp_row = MAX(s, e) + 1;
693 
694 		vtbuf_dirty(vb, &area);
695 	}
696 }
697 
698 int
699 vtbuf_get_marked_len(struct vt_buf *vb)
700 {
701 	int ei, si, sz;
702 	term_pos_t s, e;
703 
704 	/* Swap according to window coordinates. */
705 	if (POS_INDEX(vtbuf_htw(vb, vb->vb_mark_start.tp_row),
706 	    vb->vb_mark_start.tp_col) >
707 	    POS_INDEX(vtbuf_htw(vb, vb->vb_mark_end.tp_row),
708 	    vb->vb_mark_end.tp_col)) {
709 		POS_COPY(e, vb->vb_mark_start);
710 		POS_COPY(s, vb->vb_mark_end);
711 	} else {
712 		POS_COPY(s, vb->vb_mark_start);
713 		POS_COPY(e, vb->vb_mark_end);
714 	}
715 
716 	si = s.tp_row * vb->vb_scr_size.tp_col + s.tp_col;
717 	ei = e.tp_row * vb->vb_scr_size.tp_col + e.tp_col;
718 
719 	/* Number symbols and number of rows to inject \n */
720 	sz = ei - si + ((e.tp_row - s.tp_row) * 2);
721 
722 	return (sz * sizeof(term_char_t));
723 }
724 
725 void
726 vtbuf_extract_marked(struct vt_buf *vb, term_char_t *buf, int sz)
727 {
728 	int i, r, c, cs, ce;
729 	term_pos_t s, e;
730 
731 	/* Swap according to window coordinates. */
732 	if (POS_INDEX(vtbuf_htw(vb, vb->vb_mark_start.tp_row),
733 	    vb->vb_mark_start.tp_col) >
734 	    POS_INDEX(vtbuf_htw(vb, vb->vb_mark_end.tp_row),
735 	    vb->vb_mark_end.tp_col)) {
736 		POS_COPY(e, vb->vb_mark_start);
737 		POS_COPY(s, vb->vb_mark_end);
738 	} else {
739 		POS_COPY(s, vb->vb_mark_start);
740 		POS_COPY(e, vb->vb_mark_end);
741 	}
742 
743 	i = 0;
744 	for (r = s.tp_row; r <= e.tp_row; r ++) {
745 		cs = (r == s.tp_row)?s.tp_col:0;
746 		ce = (r == e.tp_row)?e.tp_col:vb->vb_scr_size.tp_col;
747 		for (c = cs; c < ce; c ++) {
748 			buf[i++] = vb->vb_rows[r][c];
749 		}
750 		/* Add new line for all rows, but not for last one. */
751 		if (r != e.tp_row) {
752 			buf[i++] = '\r';
753 			buf[i++] = '\n';
754 		}
755 	}
756 }
757 
758 int
759 vtbuf_set_mark(struct vt_buf *vb, int type, int col, int row)
760 {
761 	term_char_t *r;
762 	int i;
763 
764 	switch (type) {
765 	case VTB_MARK_END:	/* B1 UP */
766 		if (vb->vb_mark_last != VTB_MARK_MOVE)
767 			return (0);
768 		/* FALLTHROUGH */
769 	case VTB_MARK_MOVE:
770 	case VTB_MARK_EXTEND:
771 		vtbuf_flush_mark(vb); /* Clean old mark. */
772 		vb->vb_mark_end.tp_col = col;
773 		vb->vb_mark_end.tp_row = vtbuf_wth(vb, row);
774 		break;
775 	case VTB_MARK_START:
776 		vtbuf_flush_mark(vb); /* Clean old mark. */
777 		vb->vb_mark_start.tp_col = col;
778 		vb->vb_mark_start.tp_row = vtbuf_wth(vb, row);
779 		/* Start again, so clear end point. */
780 		vb->vb_mark_end.tp_col = col;
781 		vb->vb_mark_end.tp_row = vtbuf_wth(vb, row);
782 		break;
783 	case VTB_MARK_WORD:
784 		vtbuf_flush_mark(vb); /* Clean old mark. */
785 		vb->vb_mark_start.tp_row = vb->vb_mark_end.tp_row =
786 		    vtbuf_wth(vb, row);
787 		r = vb->vb_rows[vb->vb_mark_start.tp_row];
788 		for (i = col; i >= 0; i --) {
789 			if (TCHAR_CHARACTER(r[i]) == ' ') {
790 				vb->vb_mark_start.tp_col = i + 1;
791 				break;
792 			}
793 		}
794 		for (i = col; i < vb->vb_scr_size.tp_col; i ++) {
795 			if (TCHAR_CHARACTER(r[i]) == ' ') {
796 				vb->vb_mark_end.tp_col = i;
797 				break;
798 			}
799 		}
800 		if (vb->vb_mark_start.tp_col > vb->vb_mark_end.tp_col)
801 			vb->vb_mark_start.tp_col = vb->vb_mark_end.tp_col;
802 		break;
803 	case VTB_MARK_ROW:
804 		vtbuf_flush_mark(vb); /* Clean old mark. */
805 		vb->vb_mark_start.tp_col = 0;
806 		vb->vb_mark_end.tp_col = vb->vb_scr_size.tp_col;
807 		vb->vb_mark_start.tp_row = vb->vb_mark_end.tp_row =
808 		    vtbuf_wth(vb, row);
809 		break;
810 	case VTB_MARK_NONE:
811 		vb->vb_mark_last = type;
812 		/* FALLTHROUGH */
813 	default:
814 		/* panic? */
815 		return (0);
816 	}
817 
818 	vb->vb_mark_last = type;
819 	/* Draw new marked region. */
820 	vtbuf_flush_mark(vb);
821 	return (1);
822 }
823 #endif
824 
825 void
826 vtbuf_cursor_visibility(struct vt_buf *vb, int yes)
827 {
828 	int oflags, nflags;
829 
830 	VTBUF_LOCK(vb);
831 	oflags = vb->vb_flags;
832 	if (yes)
833 		vb->vb_flags |= VBF_CURSOR;
834 	else
835 		vb->vb_flags &= ~VBF_CURSOR;
836 	nflags = vb->vb_flags;
837 
838 	if (oflags != nflags)
839 		vtbuf_dirty_cell_locked(vb, &vb->vb_cursor);
840 	VTBUF_UNLOCK(vb);
841 }
842 
843 void
844 vtbuf_scroll_mode(struct vt_buf *vb, int yes)
845 {
846 	int oflags, nflags;
847 
848 	VTBUF_LOCK(vb);
849 	oflags = vb->vb_flags;
850 	if (yes)
851 		vb->vb_flags |= VBF_SCROLL;
852 	else
853 		vb->vb_flags &= ~VBF_SCROLL;
854 	nflags = vb->vb_flags;
855 
856 	if (oflags != nflags)
857 		vtbuf_dirty_cell_locked(vb, &vb->vb_cursor);
858 	VTBUF_UNLOCK(vb);
859 }
860 
861