This source file includes following definitions.
- put_tty_queue
- n_tty_flush_buffer
- n_tty_chars_in_buffer
- opost
- put_char
- echo_char
- finish_erasing
- eraser
- isig
- n_tty_receive_break
- n_tty_receive_overrun
- n_tty_receive_parity_error
- n_tty_receive_char
- n_tty_receive_buf
- n_tty_receive_room
- is_ignored
- n_tty_set_termios
- n_tty_close
- n_tty_open
- input_available_p
- copy_from_read_buf
- read_chan
- write_chan
- normal_select
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22 #include <linux/types.h>
23 #include <linux/major.h>
24 #include <linux/errno.h>
25 #include <linux/signal.h>
26 #include <linux/fcntl.h>
27 #include <linux/sched.h>
28 #include <linux/interrupt.h>
29 #include <linux/tty.h>
30 #include <linux/timer.h>
31 #include <linux/ctype.h>
32 #include <linux/kd.h>
33 #include <linux/mm.h>
34 #include <linux/string.h>
35 #include <linux/malloc.h>
36
37 #include <asm/segment.h>
38 #include <asm/system.h>
39 #include <asm/bitops.h>
40
41 #define CONSOLE_DEV MKDEV(TTY_MAJOR,0)
42
43 #ifndef MIN
44 #define MIN(a,b) ((a) < (b) ? (a) : (b))
45 #endif
46
47
48 #define WAKEUP_CHARS 256
49
50
51
52
53
54
55 #define TTY_THRESHOLD_THROTTLE (N_TTY_BUF_SIZE - 128)
56 #define TTY_THRESHOLD_UNTHROTTLE 128
57
58 static inline void put_tty_queue(unsigned char c, struct tty_struct *tty)
59 {
60 if (tty->read_cnt < N_TTY_BUF_SIZE) {
61 tty->read_buf[tty->read_head] = c;
62 tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1);
63 tty->read_cnt++;
64 }
65 }
66
67
68
69
70 void n_tty_flush_buffer(struct tty_struct * tty)
71 {
72 tty->read_head = tty->read_tail = tty->read_cnt = 0;
73 tty->canon_head = tty->canon_data = tty->erasing = 0;
74 memset(&tty->read_flags, 0, sizeof tty->read_flags);
75
76 if (!tty->link)
77 return;
78
79 if (tty->driver.unthrottle)
80 (tty->driver.unthrottle)(tty);
81 if (tty->link->packet) {
82 tty->ctrl_status |= TIOCPKT_FLUSHREAD;
83 wake_up_interruptible(&tty->link->read_wait);
84 }
85 }
86
87
88
89
90 int n_tty_chars_in_buffer(struct tty_struct *tty)
91 {
92 return tty->read_cnt;
93 }
94
95
96
97
98
99 static int opost(unsigned char c, struct tty_struct *tty)
100 {
101 int space, spaces;
102
103 space = tty->driver.write_room(tty);
104 if (!space)
105 return -1;
106
107 if (O_OPOST(tty)) {
108 switch (c) {
109 case '\n':
110 if (O_ONLRET(tty))
111 tty->column = 0;
112 if (O_ONLCR(tty)) {
113 if (space < 2)
114 return -1;
115 tty->driver.put_char(tty, '\r');
116 tty->column = 0;
117 }
118 tty->canon_column = tty->column;
119 break;
120 case '\r':
121 if (O_ONOCR(tty) && tty->column == 0)
122 return 0;
123 if (O_OCRNL(tty)) {
124 c = '\n';
125 if (O_ONLRET(tty))
126 tty->canon_column = tty->column = 0;
127 break;
128 }
129 tty->canon_column = tty->column = 0;
130 break;
131 case '\t':
132 spaces = 8 - (tty->column & 7);
133 if (O_TABDLY(tty) == XTABS) {
134 if (space < spaces)
135 return -1;
136 tty->column += spaces;
137 tty->driver.write(tty, 0, " ", spaces);
138 return 0;
139 }
140 tty->column += spaces;
141 break;
142 case '\b':
143 if (tty->column > 0)
144 tty->column--;
145 break;
146 default:
147 if (O_OLCUC(tty))
148 c = toupper(c);
149 if (!iscntrl(c))
150 tty->column++;
151 break;
152 }
153 }
154 tty->driver.put_char(tty, c);
155 return 0;
156 }
157
158 static inline void put_char(unsigned char c, struct tty_struct *tty)
159 {
160 tty->driver.put_char(tty, c);
161 }
162
163
164
165 static void echo_char(unsigned char c, struct tty_struct *tty)
166 {
167 if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') {
168 put_char('^', tty);
169 put_char(c ^ 0100, tty);
170 tty->column += 2;
171 } else
172 opost(c, tty);
173 }
174
175 static inline void finish_erasing(struct tty_struct *tty)
176 {
177 if (tty->erasing) {
178 put_char('/', tty);
179 tty->column += 2;
180 tty->erasing = 0;
181 }
182 }
183
184 static void eraser(unsigned char c, struct tty_struct *tty)
185 {
186 enum { ERASE, WERASE, KILL } kill_type;
187 int head, seen_alnums;
188
189 if (tty->read_head == tty->canon_head) {
190
191 return;
192 }
193 if (c == ERASE_CHAR(tty))
194 kill_type = ERASE;
195 else if (c == WERASE_CHAR(tty))
196 kill_type = WERASE;
197 else {
198 if (!L_ECHO(tty)) {
199 tty->read_cnt -= ((tty->read_head - tty->canon_head) &
200 (N_TTY_BUF_SIZE - 1));
201 tty->read_head = tty->canon_head;
202 return;
203 }
204 if (!L_ECHOK(tty) || !L_ECHOKE(tty)) {
205 tty->read_cnt -= ((tty->read_head - tty->canon_head) &
206 (N_TTY_BUF_SIZE - 1));
207 tty->read_head = tty->canon_head;
208 finish_erasing(tty);
209 echo_char(KILL_CHAR(tty), tty);
210
211 if (L_ECHOK(tty))
212 opost('\n', tty);
213 return;
214 }
215 kill_type = KILL;
216 }
217
218 seen_alnums = 0;
219 while (tty->read_head != tty->canon_head) {
220 head = (tty->read_head - 1) & (N_TTY_BUF_SIZE-1);
221 c = tty->read_buf[head];
222 if (kill_type == WERASE) {
223
224 if (isalnum(c) || c == '_')
225 seen_alnums++;
226 else if (seen_alnums)
227 break;
228 }
229 tty->read_head = head;
230 tty->read_cnt--;
231 if (L_ECHO(tty)) {
232 if (L_ECHOPRT(tty)) {
233 if (!tty->erasing) {
234 put_char('\\', tty);
235 tty->column++;
236 tty->erasing = 1;
237 }
238 echo_char(c, tty);
239 } else if (!L_ECHOE(tty)) {
240 echo_char(ERASE_CHAR(tty), tty);
241 } else if (c == '\t') {
242 unsigned int col = tty->canon_column;
243 unsigned long tail = tty->canon_head;
244
245
246 while (tail != tty->read_head) {
247 c = tty->read_buf[tail];
248 if (c == '\t')
249 col = (col | 7) + 1;
250 else if (iscntrl(c)) {
251 if (L_ECHOCTL(tty))
252 col += 2;
253 } else
254 col++;
255 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
256 }
257
258
259 while (tty->column > col) {
260
261 put_char('\b', tty);
262 tty->column--;
263 }
264 } else {
265 if (iscntrl(c) && L_ECHOCTL(tty)) {
266 put_char('\b', tty);
267 put_char(' ', tty);
268 put_char('\b', tty);
269 tty->column--;
270 }
271 if (!iscntrl(c) || L_ECHOCTL(tty)) {
272 put_char('\b', tty);
273 put_char(' ', tty);
274 put_char('\b', tty);
275 tty->column--;
276 }
277 }
278 }
279 if (kill_type == ERASE)
280 break;
281 }
282 if (tty->read_head == tty->canon_head)
283 finish_erasing(tty);
284 }
285
286 static void isig(int sig, struct tty_struct *tty)
287 {
288 if (tty->pgrp > 0)
289 kill_pg(tty->pgrp, sig, 1);
290 if (!L_NOFLSH(tty)) {
291 n_tty_flush_buffer(tty);
292 if (tty->driver.flush_buffer)
293 tty->driver.flush_buffer(tty);
294 }
295 }
296
297 static inline void n_tty_receive_break(struct tty_struct *tty)
298 {
299 if (I_IGNBRK(tty))
300 return;
301 if (I_BRKINT(tty)) {
302 isig(SIGINT, tty);
303 return;
304 }
305 if (I_PARMRK(tty)) {
306 put_tty_queue('\377', tty);
307 put_tty_queue('\0', tty);
308 }
309 put_tty_queue('\0', tty);
310 wake_up_interruptible(&tty->read_wait);
311 }
312
313 static inline void n_tty_receive_overrun(struct tty_struct *tty)
314 {
315 char buf[64];
316
317 tty->num_overrun++;
318 if (tty->overrun_time < (jiffies - HZ)) {
319 printk("%s: %d input overrun(s)\n", _tty_name(tty, buf),
320 tty->num_overrun);
321 tty->overrun_time = jiffies;
322 tty->num_overrun = 0;
323 }
324 }
325
326 static inline void n_tty_receive_parity_error(struct tty_struct *tty,
327 unsigned char c)
328 {
329 if (I_IGNPAR(tty)) {
330 return;
331 }
332 if (I_PARMRK(tty)) {
333 put_tty_queue('\377', tty);
334 put_tty_queue('\0', tty);
335 put_tty_queue(c, tty);
336 } else
337 put_tty_queue('\0', tty);
338 wake_up_interruptible(&tty->read_wait);
339 }
340
341 static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
342 {
343 if (tty->raw) {
344 put_tty_queue(c, tty);
345 return;
346 }
347
348 if (tty->stopped && I_IXON(tty) && I_IXANY(tty)) {
349 start_tty(tty);
350 return;
351 }
352
353 if (I_ISTRIP(tty))
354 c &= 0x7f;
355 if (I_IUCLC(tty) && L_IEXTEN(tty))
356 c=tolower(c);
357
358 if (tty->closing) {
359 if (I_IXON(tty)) {
360 if (c == START_CHAR(tty))
361 start_tty(tty);
362 else if (c == STOP_CHAR(tty))
363 stop_tty(tty);
364 }
365 return;
366 }
367
368
369
370
371
372
373
374 if (!test_bit(c, &tty->process_char_map) || tty->lnext) {
375 finish_erasing(tty);
376 tty->lnext = 0;
377 if (L_ECHO(tty)) {
378 if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
379 put_char('\a', tty);
380 return;
381 }
382
383 if (tty->canon_head == tty->read_head)
384 tty->canon_column = tty->column;
385 echo_char(c, tty);
386 }
387 if (I_PARMRK(tty) && c == (unsigned char) '\377')
388 put_tty_queue(c, tty);
389 put_tty_queue(c, tty);
390 return;
391 }
392
393 if (c == '\r') {
394 if (I_IGNCR(tty))
395 return;
396 if (I_ICRNL(tty))
397 c = '\n';
398 } else if (c == '\n' && I_INLCR(tty))
399 c = '\r';
400 if (I_IXON(tty)) {
401 if (c == START_CHAR(tty)) {
402 start_tty(tty);
403 return;
404 }
405 if (c == STOP_CHAR(tty)) {
406 stop_tty(tty);
407 return;
408 }
409 }
410 if (L_ISIG(tty)) {
411 if (c == INTR_CHAR(tty)) {
412 isig(SIGINT, tty);
413 return;
414 }
415 if (c == QUIT_CHAR(tty)) {
416 isig(SIGQUIT, tty);
417 return;
418 }
419 if (c == SUSP_CHAR(tty)) {
420 if (!is_orphaned_pgrp(tty->pgrp))
421 isig(SIGTSTP, tty);
422 return;
423 }
424 }
425 if (L_ICANON(tty)) {
426 if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
427 (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
428 eraser(c, tty);
429 return;
430 }
431 if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
432 tty->lnext = 1;
433 if (L_ECHO(tty)) {
434 finish_erasing(tty);
435 if (L_ECHOCTL(tty)) {
436 put_char('^', tty);
437 put_char('\b', tty);
438 }
439 }
440 return;
441 }
442 if (c == REPRINT_CHAR(tty) && L_ECHO(tty) &&
443 L_IEXTEN(tty)) {
444 unsigned long tail = tty->canon_head;
445
446 finish_erasing(tty);
447 echo_char(c, tty);
448 opost('\n', tty);
449 while (tail != tty->read_head) {
450 echo_char(tty->read_buf[tail], tty);
451 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
452 }
453 return;
454 }
455 if (c == '\n') {
456 if (L_ECHO(tty) || L_ECHONL(tty)) {
457 if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
458 put_char('\a', tty);
459 return;
460 }
461 opost('\n', tty);
462 }
463 goto handle_newline;
464 }
465 if (c == EOF_CHAR(tty)) {
466 if (tty->canon_head != tty->read_head)
467 set_bit(TTY_PUSH, &tty->flags);
468 c = __DISABLED_CHAR;
469 goto handle_newline;
470 }
471 if ((c == EOL_CHAR(tty)) ||
472 (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
473
474
475
476 if (L_ECHO(tty)) {
477 if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
478 put_char('\a', tty);
479 return;
480 }
481
482 if (tty->canon_head == tty->read_head)
483 tty->canon_column = tty->column;
484 echo_char(c, tty);
485 }
486
487
488
489
490 if (I_PARMRK(tty) && c == (unsigned char) '\377')
491 put_tty_queue(c, tty);
492
493 handle_newline:
494 set_bit(tty->read_head, &tty->read_flags);
495 put_tty_queue(c, tty);
496 tty->canon_head = tty->read_head;
497 tty->canon_data++;
498 if (tty->fasync)
499 kill_fasync(tty->fasync, SIGIO);
500 if (tty->read_wait)
501 wake_up_interruptible(&tty->read_wait);
502 return;
503 }
504 }
505
506 finish_erasing(tty);
507 if (L_ECHO(tty)) {
508 if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
509 put_char('\a', tty);
510 return;
511 }
512 if (c == '\n')
513 opost('\n', tty);
514 else {
515
516 if (tty->canon_head == tty->read_head)
517 tty->canon_column = tty->column;
518 echo_char(c, tty);
519 }
520 }
521
522 if (I_PARMRK(tty) && c == (unsigned char) '\377')
523 put_tty_queue(c, tty);
524
525 put_tty_queue(c, tty);
526 }
527
528 static void n_tty_receive_buf(struct tty_struct *tty, unsigned char *cp,
529 char *fp, int count)
530 {
531 unsigned char *p;
532 char *f, flags = 0;
533 int i;
534
535 if (!tty->read_buf)
536 return;
537
538 if (tty->real_raw) {
539 i = MIN(count, MIN(N_TTY_BUF_SIZE - tty->read_cnt,
540 N_TTY_BUF_SIZE - tty->read_head));
541 memcpy(tty->read_buf + tty->read_head, cp, i);
542 tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
543 tty->read_cnt += i;
544 cp += i;
545 count -= i;
546
547 i = MIN(count, MIN(N_TTY_BUF_SIZE - tty->read_cnt,
548 N_TTY_BUF_SIZE - tty->read_head));
549 memcpy(tty->read_buf + tty->read_head, cp, i);
550 tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
551 tty->read_cnt += i;
552 } else {
553 for (i=count, p = cp, f = fp; i; i--, p++) {
554 if (f)
555 flags = *f++;
556 switch (flags) {
557 case TTY_NORMAL:
558 n_tty_receive_char(tty, *p);
559 break;
560 case TTY_BREAK:
561 n_tty_receive_break(tty);
562 break;
563 case TTY_PARITY:
564 case TTY_FRAME:
565 n_tty_receive_parity_error(tty, *p);
566 break;
567 case TTY_OVERRUN:
568 n_tty_receive_overrun(tty);
569 break;
570 default:
571 printk("%s: unknown flag %d\n", tty_name(tty),
572 flags);
573 break;
574 }
575 }
576 if (tty->driver.flush_chars)
577 tty->driver.flush_chars(tty);
578 }
579
580 if (!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) {
581 if (tty->fasync)
582 kill_fasync(tty->fasync, SIGIO);
583 if (tty->read_wait)
584 wake_up_interruptible(&tty->read_wait);
585 }
586
587 if ((tty->read_cnt >= TTY_THRESHOLD_THROTTLE) &&
588 tty->driver.throttle &&
589 !set_bit(TTY_THROTTLED, &tty->flags))
590 tty->driver.throttle(tty);
591 }
592
593 static int n_tty_receive_room(struct tty_struct *tty)
594 {
595 int left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
596
597
598
599
600
601
602
603 if (tty->icanon && !tty->canon_data)
604 return N_TTY_BUF_SIZE;
605
606 if (left > 0)
607 return left;
608 return 0;
609 }
610
611 int is_ignored(int sig)
612 {
613 return ((current->blocked & (1<<(sig-1))) ||
614 (current->sigaction[sig-1].sa_handler == SIG_IGN));
615 }
616
617 static void n_tty_set_termios(struct tty_struct *tty, struct termios * old)
618 {
619 if (!tty)
620 return;
621
622 tty->icanon = (L_ICANON(tty) != 0);
623 if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
624 I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
625 I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
626 I_PARMRK(tty)) {
627 cli();
628 memset(tty->process_char_map, 0, 256/32);
629
630 if (I_IGNCR(tty) || I_ICRNL(tty))
631 set_bit('\r', &tty->process_char_map);
632 if (I_INLCR(tty))
633 set_bit('\n', &tty->process_char_map);
634
635 if (L_ICANON(tty)) {
636 set_bit(ERASE_CHAR(tty), &tty->process_char_map);
637 set_bit(KILL_CHAR(tty), &tty->process_char_map);
638 set_bit(EOF_CHAR(tty), &tty->process_char_map);
639 set_bit('\n', &tty->process_char_map);
640 set_bit(EOL_CHAR(tty), &tty->process_char_map);
641 if (L_IEXTEN(tty)) {
642 set_bit(WERASE_CHAR(tty),
643 &tty->process_char_map);
644 set_bit(LNEXT_CHAR(tty),
645 &tty->process_char_map);
646 set_bit(EOL2_CHAR(tty),
647 &tty->process_char_map);
648 if (L_ECHO(tty))
649 set_bit(REPRINT_CHAR(tty),
650 &tty->process_char_map);
651 }
652 }
653 if (I_IXON(tty)) {
654 set_bit(START_CHAR(tty), &tty->process_char_map);
655 set_bit(STOP_CHAR(tty), &tty->process_char_map);
656 }
657 if (L_ISIG(tty)) {
658 set_bit(INTR_CHAR(tty), &tty->process_char_map);
659 set_bit(QUIT_CHAR(tty), &tty->process_char_map);
660 set_bit(SUSP_CHAR(tty), &tty->process_char_map);
661 }
662 clear_bit(__DISABLED_CHAR, &tty->process_char_map);
663 sti();
664 tty->raw = 0;
665 tty->real_raw = 0;
666 } else {
667 tty->raw = 1;
668 if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
669 (I_IGNPAR(tty) || !I_INPCK(tty)) &&
670 (tty->driver.flags & TTY_DRIVER_REAL_RAW))
671 tty->real_raw = 1;
672 else
673 tty->real_raw = 0;
674 }
675 }
676
677 static void n_tty_close(struct tty_struct *tty)
678 {
679 tty_wait_until_sent(tty, 0);
680 n_tty_flush_buffer(tty);
681 if (tty->read_buf) {
682 free_page((unsigned long) tty->read_buf);
683 tty->read_buf = 0;
684 }
685 }
686
687 static int n_tty_open(struct tty_struct *tty)
688 {
689 if (!tty)
690 return -EINVAL;
691
692 if (!tty->read_buf) {
693 tty->read_buf = (unsigned char *)
694 get_free_page(intr_count ? GFP_ATOMIC : GFP_KERNEL);
695 if (!tty->read_buf)
696 return -ENOMEM;
697 }
698 memset(tty->read_buf, 0, N_TTY_BUF_SIZE);
699 tty->read_head = tty->read_tail = tty->read_cnt = 0;
700 memset(tty->read_flags, 0, sizeof(tty->read_flags));
701 n_tty_set_termios(tty, 0);
702 tty->minimum_to_wake = 1;
703 tty->closing = 0;
704 return 0;
705 }
706
707 static inline int input_available_p(struct tty_struct *tty, int amt)
708 {
709 if (L_ICANON(tty)) {
710 if (tty->canon_data)
711 return 1;
712 } else if (tty->read_cnt >= (amt ? amt : 1))
713 return 1;
714
715 return 0;
716 }
717
718
719
720
721
722
723
724
725
726 static inline void copy_from_read_buf(struct tty_struct *tty,
727 unsigned char **b,
728 unsigned int *nr)
729
730 {
731 int n;
732
733 n = MIN(*nr, MIN(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail));
734 if (!n)
735 return;
736 memcpy_tofs(*b, &tty->read_buf[tty->read_tail], n);
737 tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1);
738 tty->read_cnt -= n;
739 *b += n;
740 *nr -= n;
741 }
742
743 static int read_chan(struct tty_struct *tty, struct file *file,
744 unsigned char *buf, unsigned int nr)
745 {
746 struct wait_queue wait = { current, NULL };
747 int c;
748 unsigned char *b = buf;
749 int minimum, time;
750 int retval = 0;
751 int size;
752
753 do_it_again:
754
755 if (!tty->read_buf) {
756 printk("n_tty_read_chan: called with read_buf == NULL?!?\n");
757 return -EIO;
758 }
759
760
761
762
763
764
765 if (file->f_inode->i_rdev != CONSOLE_DEV &&
766 current->tty == tty) {
767 if (tty->pgrp <= 0)
768 printk("read_chan: tty->pgrp <= 0!\n");
769 else if (current->pgrp != tty->pgrp) {
770 if (is_ignored(SIGTTIN) ||
771 is_orphaned_pgrp(current->pgrp))
772 return -EIO;
773 kill_pg(current->pgrp, SIGTTIN, 1);
774 return -ERESTARTSYS;
775 }
776 }
777
778 if (L_ICANON(tty)) {
779 minimum = time = 0;
780 current->timeout = (unsigned long) -1;
781 } else {
782 time = (HZ / 10) * TIME_CHAR(tty);
783 minimum = MIN_CHAR(tty);
784 if (minimum) {
785 current->timeout = (unsigned long) -1;
786 if (time)
787 tty->minimum_to_wake = 1;
788 else if (!tty->read_wait ||
789 (tty->minimum_to_wake > minimum))
790 tty->minimum_to_wake = minimum;
791 } else {
792 if (time) {
793 current->timeout = time + jiffies;
794 time = 0;
795 } else
796 current->timeout = 0;
797 tty->minimum_to_wake = minimum = 1;
798 }
799 }
800
801 add_wait_queue(&tty->read_wait, &wait);
802 while (1) {
803
804 if (tty->packet && tty->link->ctrl_status) {
805 if (b != buf)
806 break;
807 put_fs_byte(tty->link->ctrl_status, b++);
808 tty->link->ctrl_status = 0;
809 break;
810 }
811
812
813
814 current->state = TASK_INTERRUPTIBLE;
815
816 if (((minimum - (b - buf)) < tty->minimum_to_wake) &&
817 ((minimum - (b - buf)) >= 1))
818 tty->minimum_to_wake = (minimum - (b - buf));
819
820 if (!input_available_p(tty, 0)) {
821 if (tty->flags & (1 << TTY_SLAVE_CLOSED)) {
822 retval = -EIO;
823 break;
824 }
825 if (tty_hung_up_p(file))
826 break;
827 if (!current->timeout)
828 break;
829 if (file->f_flags & O_NONBLOCK) {
830 retval = -EAGAIN;
831 break;
832 }
833 if (current->signal & ~current->blocked) {
834 retval = -ERESTARTSYS;
835 break;
836 }
837 schedule();
838 continue;
839 }
840 current->state = TASK_RUNNING;
841
842
843 if (tty->packet && b == buf) {
844 put_fs_byte(TIOCPKT_DATA, b++);
845 nr--;
846 }
847
848 if (L_ICANON(tty)) {
849 while (1) {
850 int eol;
851
852 disable_bh(TQUEUE_BH);
853 if (!tty->read_cnt) {
854 enable_bh(TQUEUE_BH);
855 break;
856 }
857 eol = clear_bit(tty->read_tail,
858 &tty->read_flags);
859 c = tty->read_buf[tty->read_tail];
860 tty->read_tail = ((tty->read_tail+1) &
861 (N_TTY_BUF_SIZE-1));
862 tty->read_cnt--;
863 enable_bh(TQUEUE_BH);
864 if (!eol) {
865 put_fs_byte(c, b++);
866 if (--nr)
867 continue;
868 break;
869 }
870 if (--tty->canon_data < 0) {
871 tty->canon_data = 0;
872 }
873 if (c != __DISABLED_CHAR) {
874 put_fs_byte(c, b++);
875 nr--;
876 }
877 break;
878 }
879 } else {
880 disable_bh(TQUEUE_BH);
881 copy_from_read_buf(tty, &b, &nr);
882 copy_from_read_buf(tty, &b, &nr);
883 enable_bh(TQUEUE_BH);
884 }
885
886
887
888 if (tty->driver.unthrottle &&
889 (tty->read_cnt <= TTY_THRESHOLD_UNTHROTTLE)
890 && clear_bit(TTY_THROTTLED, &tty->flags))
891 tty->driver.unthrottle(tty);
892
893 if (b - buf >= minimum || !nr)
894 break;
895 if (time)
896 current->timeout = time + jiffies;
897 }
898 remove_wait_queue(&tty->read_wait, &wait);
899
900 if (!tty->read_wait)
901 tty->minimum_to_wake = minimum;
902
903 current->state = TASK_RUNNING;
904 current->timeout = 0;
905 size = b - buf;
906 if (size && nr)
907 clear_bit(TTY_PUSH, &tty->flags);
908 if (!size && clear_bit(TTY_PUSH, &tty->flags))
909 goto do_it_again;
910 if (!size && !retval)
911 clear_bit(TTY_PUSH, &tty->flags);
912 return (size ? size : retval);
913 }
914
915 static int write_chan(struct tty_struct * tty, struct file * file,
916 unsigned char * buf, unsigned int nr)
917 {
918 struct wait_queue wait = { current, NULL };
919 int c;
920 unsigned char *b = buf;
921 int retval = 0;
922
923
924 if (L_TOSTOP(tty) && file->f_inode->i_rdev != CONSOLE_DEV) {
925 retval = tty_check_change(tty);
926 if (retval)
927 return retval;
928 }
929
930 add_wait_queue(&tty->write_wait, &wait);
931 while (1) {
932 current->state = TASK_INTERRUPTIBLE;
933 if (current->signal & ~current->blocked) {
934 retval = -ERESTARTSYS;
935 break;
936 }
937 if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) {
938 retval = -EIO;
939 break;
940 }
941 if (O_OPOST(tty)) {
942 while (nr > 0) {
943 c = get_fs_byte(b);
944 if (opost(c, tty) < 0)
945 break;
946 b++; nr--;
947 }
948 if (tty->driver.flush_chars)
949 tty->driver.flush_chars(tty);
950 } else {
951 c = tty->driver.write(tty, 1, b, nr);
952 b += c;
953 nr -= c;
954 }
955 if (!nr)
956 break;
957 if (file->f_flags & O_NONBLOCK) {
958 retval = -EAGAIN;
959 break;
960 }
961 schedule();
962 }
963 current->state = TASK_RUNNING;
964 remove_wait_queue(&tty->write_wait, &wait);
965 return (b - buf) ? b - buf : retval;
966 }
967
968 static int normal_select(struct tty_struct * tty, struct inode * inode,
969 struct file * file, int sel_type, select_table *wait)
970 {
971 switch (sel_type) {
972 case SEL_IN:
973 if (input_available_p(tty, TIME_CHAR(tty) ? 0 :
974 MIN_CHAR(tty)))
975 return 1;
976
977 case SEL_EX:
978 if (tty->packet && tty->link->ctrl_status)
979 return 1;
980 if (tty->flags & (1 << TTY_SLAVE_CLOSED))
981 return 1;
982 if (tty_hung_up_p(file))
983 return 1;
984 if (!tty->read_wait) {
985 if (MIN_CHAR(tty) && !TIME_CHAR(tty))
986 tty->minimum_to_wake = MIN_CHAR(tty);
987 else
988 tty->minimum_to_wake = 1;
989 }
990 select_wait(&tty->read_wait, wait);
991 return 0;
992 case SEL_OUT:
993 if (tty->driver.chars_in_buffer(tty) < WAKEUP_CHARS)
994 return 1;
995 select_wait(&tty->write_wait, wait);
996 return 0;
997 }
998 return 0;
999 }
1000
1001 struct tty_ldisc tty_ldisc_N_TTY = {
1002 TTY_LDISC_MAGIC,
1003 0,
1004 0,
1005 n_tty_open,
1006 n_tty_close,
1007 n_tty_flush_buffer,
1008 n_tty_chars_in_buffer,
1009 read_chan,
1010 write_chan,
1011 n_tty_ioctl,
1012 n_tty_set_termios,
1013 normal_select,
1014 n_tty_receive_buf,
1015 n_tty_receive_room,
1016 0
1017 };
1018