2 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
5 * Portions of this software were developed under sponsorship from Snow
6 * B.V., the Netherlands.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 #include <sys/param.h>
34 #include <sys/kernel.h>
36 #include <sys/queue.h>
37 #include <sys/sysctl.h>
38 #include <sys/systm.h>
45 * TTY input queue buffering.
47 * Unlike the output queue, the input queue has more features that are
48 * needed to properly implement various features offered by the TTY
51 * - Data can be removed from the tail of the queue, which is used to
52 * implement backspace.
53 * - Once in a while, input has to be `canonicalized'. When ICANON is
54 * turned on, this will be done after a CR has been inserted.
55 * Otherwise, it should be done after any character has been inserted.
56 * - The input queue can store one bit per byte, called the quoting bit.
57 * This bit is used by TTYDISC to make backspace work on quoted
60 * In most cases, there is probably less input than output, so unlike
61 * the outq, we'll stick to 128 byte blocks here.
65 static long ttyinq_nfast = 0;
66 SYSCTL_LONG(_kern, OID_AUTO, tty_inq_nfast, CTLFLAG_RD,
67 &ttyinq_nfast, 0, "Unbuffered reads to userspace on input");
68 static long ttyinq_nslow = 0;
69 SYSCTL_LONG(_kern, OID_AUTO, tty_inq_nslow, CTLFLAG_RD,
70 &ttyinq_nslow, 0, "Buffered reads to userspace on input");
72 #define TTYINQ_QUOTESIZE (TTYINQ_DATASIZE / BMSIZE)
74 #define GETBIT(tib,boff) \
75 ((tib)->tib_quotes[(boff) / BMSIZE] & (1 << ((boff) % BMSIZE)))
76 #define SETBIT(tib,boff) \
77 ((tib)->tib_quotes[(boff) / BMSIZE] |= (1 << ((boff) % BMSIZE)))
78 #define CLRBIT(tib,boff) \
79 ((tib)->tib_quotes[(boff) / BMSIZE] &= ~(1 << ((boff) % BMSIZE)))
82 TAILQ_ENTRY(ttyinq_block) tib_list;
83 uint32_t tib_quotes[TTYINQ_QUOTESIZE];
84 char tib_data[TTYINQ_DATASIZE];
87 static uma_zone_t ttyinq_zone;
90 ttyinq_setsize(struct ttyinq *ti, struct tty *tp, size_t size)
92 struct ttyinq_block *tib;
94 ti->ti_quota = howmany(size, TTYINQ_DATASIZE);
96 while (ti->ti_quota > ti->ti_nblocks) {
98 * List is getting bigger.
99 * Add new blocks to the tail of the list.
101 * We must unlock the TTY temporarily, because we need
102 * to allocate memory. This won't be a problem, because
103 * in the worst case, another thread ends up here, which
104 * may cause us to allocate too many blocks, but this
105 * will be caught by the loop below.
108 tib = uma_zalloc(ttyinq_zone, M_WAITOK);
111 TAILQ_INSERT_TAIL(&ti->ti_list, tib, tib_list);
117 ttyinq_free(struct ttyinq *ti)
119 struct ttyinq_block *tib;
124 while ((tib = TAILQ_FIRST(&ti->ti_list)) != NULL) {
125 TAILQ_REMOVE(&ti->ti_list, tib, tib_list);
126 uma_zfree(ttyinq_zone, tib);
130 MPASS(ti->ti_nblocks == 0);
134 ttyinq_read_uio(struct ttyinq *ti, struct tty *tp, struct uio *uio,
135 size_t rlen, size_t flen)
138 MPASS(rlen <= uio->uio_resid);
142 struct ttyinq_block *tib;
143 size_t cbegin, cend, clen;
145 /* See if there still is data. */
146 if (ti->ti_begin == ti->ti_linestart)
148 tib = TAILQ_FIRST(&ti->ti_list);
153 * The end address should be the lowest of these three:
154 * - The write pointer
155 * - The blocksize - we can't read beyond the block
156 * - The end address if we could perform the full read
158 cbegin = ti->ti_begin;
159 cend = MIN(MIN(ti->ti_linestart, ti->ti_begin + rlen),
161 clen = cend - cbegin;
166 * We can prevent buffering in some cases:
167 * - We need to read the block until the end.
168 * - We don't need to read the block until the end, but
169 * there is no data beyond it, which allows us to move
170 * the write pointer to a new block.
172 if (cend == TTYINQ_DATASIZE || cend == ti->ti_end) {
173 atomic_add_long(&ttyinq_nfast, 1);
176 * Fast path: zero copy. Remove the first block,
177 * so we can unlock the TTY temporarily.
179 TAILQ_REMOVE(&ti->ti_list, tib, tib_list);
184 * Because we remove the first block, we must
185 * fix up the block offsets.
187 #define CORRECT_BLOCK(t) do { \
188 if (t <= TTYINQ_DATASIZE) { \
191 t -= TTYINQ_DATASIZE; \
194 CORRECT_BLOCK(ti->ti_linestart);
195 CORRECT_BLOCK(ti->ti_reprint);
196 CORRECT_BLOCK(ti->ti_end);
200 * Temporary unlock and copy the data to
201 * userspace. We may need to flush trailing
202 * bytes, like EOF characters.
205 error = uiomove(tib->tib_data + cbegin,
209 /* Block can now be readded to the list. */
210 if (ti->ti_quota <= ti->ti_nblocks) {
211 uma_zfree(ttyinq_zone, tib);
213 TAILQ_INSERT_TAIL(&ti->ti_list, tib, tib_list);
217 char ob[TTYINQ_DATASIZE - 1];
218 atomic_add_long(&ttyinq_nslow, 1);
221 * Slow path: store data in a temporary buffer.
223 memcpy(ob, tib->tib_data + cbegin, clen - flen);
224 ti->ti_begin += clen;
225 MPASS(ti->ti_begin < TTYINQ_DATASIZE);
227 /* Temporary unlock and copy the data to userspace. */
229 error = uiomove(ob, clen - flen, uio);
243 ttyinq_set_quotes(struct ttyinq_block *tib, size_t offset,
244 size_t length, int value)
249 for (; length > 0; length--, offset++)
252 /* Unset the bits. */
253 for (; length > 0; length--, offset++)
259 ttyinq_write(struct ttyinq *ti, const void *buf, size_t nbytes, int quote)
261 const char *cbuf = buf;
262 struct ttyinq_block *tib;
267 tib = ti->ti_lastblock;
268 boff = ti->ti_end % TTYINQ_DATASIZE;
270 if (ti->ti_end == 0) {
271 /* First time we're being used or drained. */
272 MPASS(ti->ti_begin == 0);
273 tib = ti->ti_lastblock = TAILQ_FIRST(&ti->ti_list);
275 /* Queue has no blocks. */
278 } else if (boff == 0) {
279 /* We reached the end of this block on last write. */
280 tib = TAILQ_NEXT(tib, tib_list);
282 /* We've reached the watermark. */
285 ti->ti_lastblock = tib;
288 /* Don't copy more than was requested. */
289 l = MIN(nbytes, TTYINQ_DATASIZE - boff);
291 memcpy(tib->tib_data + boff, cbuf, l);
293 /* Set the quoting bits for the proper region. */
294 ttyinq_set_quotes(tib, boff, l, quote);
301 return (cbuf - (const char *)buf);
305 ttyinq_write_nofrag(struct ttyinq *ti, const void *buf, size_t nbytes, int quote)
309 if (ttyinq_bytesleft(ti) < nbytes)
312 /* We should always be able to write it back. */
313 ret = ttyinq_write(ti, buf, nbytes, quote);
314 MPASS(ret == nbytes);
320 ttyinq_canonicalize(struct ttyinq *ti)
323 ti->ti_linestart = ti->ti_reprint = ti->ti_end;
324 ti->ti_startblock = ti->ti_reprintblock = ti->ti_lastblock;
328 ttyinq_findchar(struct ttyinq *ti, const char *breakc, size_t maxlen,
331 struct ttyinq_block *tib = TAILQ_FIRST(&ti->ti_list);
332 unsigned int boff = ti->ti_begin;
333 unsigned int bend = MIN(MIN(TTYINQ_DATASIZE, ti->ti_linestart),
334 ti->ti_begin + maxlen);
341 while (boff < bend) {
342 if (index(breakc, tib->tib_data[boff]) && !GETBIT(tib, boff)) {
343 *lastc = tib->tib_data[boff];
344 return (boff - ti->ti_begin + 1);
349 /* Not found - just process the entire block. */
350 return (bend - ti->ti_begin);
354 ttyinq_flush(struct ttyinq *ti)
358 ti->ti_linestart = 0;
365 ttyinq_flush_safe(struct ttyinq *ti)
367 struct ttyinq_block *tib;
371 /* Zero all data in the input queue to make it more safe */
372 TAILQ_FOREACH(tib, &ti->ti_list, tib_list) {
373 bzero(&tib->tib_quotes, sizeof tib->tib_quotes);
374 bzero(&tib->tib_data, sizeof tib->tib_data);
380 ttyinq_peekchar(struct ttyinq *ti, char *c, int *quote)
383 struct ttyinq_block *tib = ti->ti_lastblock;
385 if (ti->ti_linestart == ti->ti_end)
388 MPASS(ti->ti_end > 0);
389 boff = (ti->ti_end - 1) % TTYINQ_DATASIZE;
391 *c = tib->tib_data[boff];
392 *quote = GETBIT(tib, boff);
398 ttyinq_unputchar(struct ttyinq *ti)
401 MPASS(ti->ti_linestart < ti->ti_end);
403 if (--ti->ti_end % TTYINQ_DATASIZE == 0) {
404 /* Roll back to the previous block. */
405 ti->ti_lastblock = TAILQ_PREV(ti->ti_lastblock,
406 ttyinq_bhead, tib_list);
408 * This can only fail if we are unputchar()'ing the
409 * first character in the queue.
411 MPASS((ti->ti_lastblock == NULL) == (ti->ti_end == 0));
416 ttyinq_reprintpos_set(struct ttyinq *ti)
419 ti->ti_reprint = ti->ti_end;
420 ti->ti_reprintblock = ti->ti_lastblock;
424 ttyinq_reprintpos_reset(struct ttyinq *ti)
427 ti->ti_reprint = ti->ti_linestart;
428 ti->ti_reprintblock = ti->ti_startblock;
432 ttyinq_line_iterate(struct ttyinq *ti,
433 ttyinq_line_iterator_t *iterator, void *data,
434 unsigned int offset, struct ttyinq_block *tib)
438 /* Use the proper block when we're at the queue head. */
440 tib = TAILQ_FIRST(&ti->ti_list);
442 /* Iterate all characters and call the iterator function. */
443 for (; offset < ti->ti_end; offset++) {
444 boff = offset % TTYINQ_DATASIZE;
447 /* Call back the iterator function. */
448 iterator(data, tib->tib_data[boff], GETBIT(tib, boff));
450 /* Last byte iterated - go to the next block. */
451 if (boff == TTYINQ_DATASIZE - 1)
452 tib = TAILQ_NEXT(tib, tib_list);
458 ttyinq_line_iterate_from_linestart(struct ttyinq *ti,
459 ttyinq_line_iterator_t *iterator, void *data)
462 ttyinq_line_iterate(ti, iterator, data,
463 ti->ti_linestart, ti->ti_startblock);
467 ttyinq_line_iterate_from_reprintpos(struct ttyinq *ti,
468 ttyinq_line_iterator_t *iterator, void *data)
471 ttyinq_line_iterate(ti, iterator, data,
472 ti->ti_reprint, ti->ti_reprintblock);
476 ttyinq_startup(void *dummy)
479 ttyinq_zone = uma_zcreate("ttyinq", sizeof(struct ttyinq_block),
480 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
483 SYSINIT(ttyinq, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyinq_startup, NULL);