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) && L_IEXTEN(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
359
360
361
362
363
364 if (!test_bit(c, &tty->process_char_map) || tty->lnext) {
365 finish_erasing(tty);
366 tty->lnext = 0;
367 if (L_ECHO(tty)) {
368 if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
369 put_char('\a', tty);
370 return;
371 }
372
373 if (tty->canon_head == tty->read_head)
374 tty->canon_column = tty->column;
375 echo_char(c, tty);
376 }
377 if (I_PARMRK(tty) && c == (unsigned char) '\377')
378 put_tty_queue(c, tty);
379 put_tty_queue(c, tty);
380 return;
381 }
382
383 if (c == '\r') {
384 if (I_IGNCR(tty))
385 return;
386 if (I_ICRNL(tty))
387 c = '\n';
388 } else if (c == '\n' && I_INLCR(tty))
389 c = '\r';
390 if (I_IXON(tty)) {
391 if (c == START_CHAR(tty)) {
392 start_tty(tty);
393 return;
394 }
395 if (c == STOP_CHAR(tty)) {
396 stop_tty(tty);
397 return;
398 }
399 }
400 if (L_ISIG(tty)) {
401 if (c == INTR_CHAR(tty)) {
402 isig(SIGINT, tty);
403 return;
404 }
405 if (c == QUIT_CHAR(tty)) {
406 isig(SIGQUIT, tty);
407 return;
408 }
409 if (c == SUSP_CHAR(tty)) {
410 if (!is_orphaned_pgrp(tty->pgrp))
411 isig(SIGTSTP, tty);
412 return;
413 }
414 }
415 if (L_ICANON(tty)) {
416 if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
417 (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
418 eraser(c, tty);
419 return;
420 }
421 if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
422 tty->lnext = 1;
423 if (L_ECHO(tty)) {
424 finish_erasing(tty);
425 if (L_ECHOCTL(tty)) {
426 put_char('^', tty);
427 put_char('\b', tty);
428 }
429 }
430 return;
431 }
432 if (c == REPRINT_CHAR(tty) && L_ECHO(tty) &&
433 L_IEXTEN(tty)) {
434 unsigned long tail = tty->canon_head;
435
436 finish_erasing(tty);
437 echo_char(c, tty);
438 opost('\n', tty);
439 while (tail != tty->read_head) {
440 echo_char(tty->read_buf[tail], tty);
441 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
442 }
443 return;
444 }
445 if (c == '\n') {
446 if (L_ECHO(tty) || L_ECHONL(tty)) {
447 if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
448 put_char('\a', tty);
449 return;
450 }
451 opost('\n', tty);
452 }
453 goto handle_newline;
454 }
455 if (c == EOF_CHAR(tty)) {
456 if (tty->canon_head != tty->read_head)
457 set_bit(TTY_PUSH, &tty->flags);
458 c = __DISABLED_CHAR;
459 goto handle_newline;
460 }
461 if ((c == EOL_CHAR(tty)) ||
462 (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
463
464
465
466 if (L_ECHO(tty)) {
467 if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
468 put_char('\a', tty);
469 return;
470 }
471
472 if (tty->canon_head == tty->read_head)
473 tty->canon_column = tty->column;
474 echo_char(c, tty);
475 }
476
477
478
479
480 if (I_PARMRK(tty) && c == (unsigned char) '\377')
481 put_tty_queue(c, tty);
482
483 handle_newline:
484 set_bit(tty->read_head, &tty->read_flags);
485 put_tty_queue(c, tty);
486 tty->canon_head = tty->read_head;
487 tty->canon_data++;
488 if (tty->fasync)
489 kill_fasync(tty->fasync, SIGIO);
490 if (tty->read_wait)
491 wake_up_interruptible(&tty->read_wait);
492 return;
493 }
494 }
495
496 finish_erasing(tty);
497 if (L_ECHO(tty)) {
498 if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
499 put_char('\a', tty);
500 return;
501 }
502 if (c == '\n')
503 opost('\n', tty);
504 else {
505
506 if (tty->canon_head == tty->read_head)
507 tty->canon_column = tty->column;
508 echo_char(c, tty);
509 }
510 }
511
512 if (I_PARMRK(tty) && c == (unsigned char) '\377')
513 put_tty_queue(c, tty);
514
515 put_tty_queue(c, tty);
516 }
517
518 static void n_tty_receive_buf(struct tty_struct *tty, unsigned char *cp,
519 char *fp, int count)
520 {
521 unsigned char *p;
522 char *f, flags = 0;
523 int i;
524
525 if (!tty->read_buf)
526 return;
527
528 if (tty->real_raw) {
529 i = MIN(count, MIN(N_TTY_BUF_SIZE - tty->read_cnt,
530 N_TTY_BUF_SIZE - tty->read_head));
531 memcpy(tty->read_buf + tty->read_head, cp, i);
532 tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
533 tty->read_cnt += i;
534 cp += i;
535 count -= i;
536
537 i = MIN(count, MIN(N_TTY_BUF_SIZE - tty->read_cnt,
538 N_TTY_BUF_SIZE - tty->read_head));
539 memcpy(tty->read_buf + tty->read_head, cp, i);
540 tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
541 tty->read_cnt += i;
542 } else {
543 for (i=count, p = cp, f = fp; i; i--, p++) {
544 if (f)
545 flags = *f++;
546 switch (flags) {
547 case TTY_NORMAL:
548 n_tty_receive_char(tty, *p);
549 break;
550 case TTY_BREAK:
551 n_tty_receive_break(tty);
552 break;
553 case TTY_PARITY:
554 case TTY_FRAME:
555 n_tty_receive_parity_error(tty, *p);
556 break;
557 case TTY_OVERRUN:
558 n_tty_receive_overrun(tty);
559 break;
560 default:
561 printk("%s: unknown flag %d\n", tty_name(tty),
562 flags);
563 break;
564 }
565 }
566 if (tty->driver.flush_chars)
567 tty->driver.flush_chars(tty);
568 }
569
570 if (!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) {
571 if (tty->fasync)
572 kill_fasync(tty->fasync, SIGIO);
573 if (tty->read_wait)
574 wake_up_interruptible(&tty->read_wait);
575 }
576
577 if ((tty->read_cnt >= TTY_THRESHOLD_THROTTLE) &&
578 tty->driver.throttle &&
579 !set_bit(TTY_THROTTLED, &tty->flags))
580 tty->driver.throttle(tty);
581 }
582
583 static int n_tty_receive_room(struct tty_struct *tty)
584 {
585 int left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
586
587
588
589
590
591
592 if (L_ICANON(tty))
593 return N_TTY_BUF_SIZE;
594
595 if (left > 0)
596 return left;
597 return 0;
598 }
599
600 int is_ignored(int sig)
601 {
602 return ((current->blocked & (1<<(sig-1))) ||
603 (current->sigaction[sig-1].sa_handler == SIG_IGN));
604 }
605
606 static void n_tty_set_termios(struct tty_struct *tty, struct termios * old)
607 {
608 if (!tty)
609 return;
610
611 tty->icanon = (L_ICANON(tty) != 0);
612 if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
613 I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
614 I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
615 I_PARMRK(tty)) {
616 cli();
617 memset(tty->process_char_map, 0, 256/32);
618
619 if (I_IGNCR(tty) || I_ICRNL(tty))
620 set_bit('\r', &tty->process_char_map);
621 if (I_INLCR(tty))
622 set_bit('\n', &tty->process_char_map);
623
624 if (L_ICANON(tty)) {
625 set_bit(ERASE_CHAR(tty), &tty->process_char_map);
626 set_bit(KILL_CHAR(tty), &tty->process_char_map);
627 set_bit(EOF_CHAR(tty), &tty->process_char_map);
628 set_bit('\n', &tty->process_char_map);
629 set_bit(EOL_CHAR(tty), &tty->process_char_map);
630 if (L_IEXTEN(tty)) {
631 set_bit(WERASE_CHAR(tty),
632 &tty->process_char_map);
633 set_bit(LNEXT_CHAR(tty),
634 &tty->process_char_map);
635 set_bit(EOL2_CHAR(tty),
636 &tty->process_char_map);
637 if (L_ECHO(tty))
638 set_bit(REPRINT_CHAR(tty),
639 &tty->process_char_map);
640 }
641 }
642 if (I_IXON(tty)) {
643 set_bit(START_CHAR(tty), &tty->process_char_map);
644 set_bit(STOP_CHAR(tty), &tty->process_char_map);
645 }
646 if (L_ISIG(tty)) {
647 set_bit(INTR_CHAR(tty), &tty->process_char_map);
648 set_bit(QUIT_CHAR(tty), &tty->process_char_map);
649 set_bit(SUSP_CHAR(tty), &tty->process_char_map);
650 }
651 clear_bit(__DISABLED_CHAR, &tty->process_char_map);
652 sti();
653 tty->raw = 0;
654 tty->real_raw = 0;
655 } else {
656 tty->raw = 1;
657 if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
658 (I_IGNPAR(tty) || !I_INPCK(tty)) &&
659 (tty->driver.flags & TTY_DRIVER_REAL_RAW))
660 tty->real_raw = 1;
661 else
662 tty->real_raw = 0;
663 }
664 }
665
666 static void n_tty_close(struct tty_struct *tty)
667 {
668 wait_until_sent(tty, 0);
669 n_tty_flush_buffer(tty);
670 if (tty->read_buf) {
671 free_page((unsigned long) tty->read_buf);
672 tty->read_buf = 0;
673 }
674 }
675
676 static int n_tty_open(struct tty_struct *tty)
677 {
678 if (!tty)
679 return -EINVAL;
680
681 if (!tty->read_buf) {
682 tty->read_buf = (unsigned char *)
683 get_free_page(intr_count ? GFP_ATOMIC : GFP_KERNEL);
684 if (!tty->read_buf)
685 return -ENOMEM;
686 }
687 memset(tty->read_buf, 0, N_TTY_BUF_SIZE);
688 tty->read_head = tty->read_tail = tty->read_cnt = 0;
689 memset(tty->read_flags, 0, sizeof(tty->read_flags));
690 n_tty_set_termios(tty, 0);
691 tty->minimum_to_wake = 1;
692 return 0;
693 }
694
695 static inline int input_available_p(struct tty_struct *tty, int amt)
696 {
697 if (L_ICANON(tty)) {
698 if (tty->canon_data)
699 return 1;
700 } else if (tty->read_cnt >= (amt ? amt : 1))
701 return 1;
702
703 return 0;
704 }
705
706
707
708
709
710
711
712
713
714 static inline void copy_from_read_buf(struct tty_struct *tty,
715 unsigned char **b,
716 unsigned int *nr)
717
718 {
719 int n;
720
721 n = MIN(*nr, MIN(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail));
722 if (!n)
723 return;
724 memcpy_tofs(*b, &tty->read_buf[tty->read_tail], n);
725 tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1);
726 tty->read_cnt -= n;
727 *b += n;
728 *nr -= n;
729 }
730
731 static int read_chan(struct tty_struct *tty, struct file *file,
732 unsigned char *buf, unsigned int nr)
733 {
734 struct wait_queue wait = { current, NULL };
735 int c;
736 unsigned char *b = buf;
737 int minimum, time;
738 int retval = 0;
739 int size;
740
741 do_it_again:
742
743 if (!tty->read_buf) {
744 printk("n_tty_read_chan: called with read_buf == NULL?!?\n");
745 return -EIO;
746 }
747
748
749
750
751
752
753 if (file->f_inode->i_rdev != CONSOLE_DEV &&
754 current->tty == tty) {
755 if (tty->pgrp <= 0)
756 printk("read_chan: tty->pgrp <= 0!\n");
757 else if (current->pgrp != tty->pgrp) {
758 if (is_ignored(SIGTTIN) ||
759 is_orphaned_pgrp(current->pgrp))
760 return -EIO;
761 kill_pg(current->pgrp, SIGTTIN, 1);
762 return -ERESTARTSYS;
763 }
764 }
765
766 if (L_ICANON(tty)) {
767 minimum = time = 0;
768 current->timeout = (unsigned long) -1;
769 } else {
770 time = (HZ / 10) * TIME_CHAR(tty);
771 minimum = MIN_CHAR(tty);
772 if (minimum) {
773 current->timeout = (unsigned long) -1;
774 if (time)
775 tty->minimum_to_wake = 1;
776 else if (!tty->read_wait ||
777 (tty->minimum_to_wake > minimum))
778 tty->minimum_to_wake = minimum;
779 } else {
780 if (time) {
781 current->timeout = time + jiffies;
782 time = 0;
783 } else
784 current->timeout = 0;
785 tty->minimum_to_wake = minimum = 1;
786 }
787 }
788
789 add_wait_queue(&tty->read_wait, &wait);
790 while (1) {
791
792 if (tty->packet && tty->link->ctrl_status) {
793 if (b != buf)
794 break;
795 put_fs_byte(tty->link->ctrl_status, b++);
796 tty->link->ctrl_status = 0;
797 break;
798 }
799
800
801
802 current->state = TASK_INTERRUPTIBLE;
803
804 if (((minimum - (b - buf)) < tty->minimum_to_wake) &&
805 ((minimum - (b - buf)) >= 1))
806 tty->minimum_to_wake = (minimum - (b - buf));
807
808 if (!input_available_p(tty, 0)) {
809 if (tty->flags & (1 << TTY_SLAVE_CLOSED)) {
810 retval = -EIO;
811 break;
812 }
813 if (tty_hung_up_p(file))
814 break;
815 if (!current->timeout)
816 break;
817 if (file->f_flags & O_NONBLOCK) {
818 retval = -EAGAIN;
819 break;
820 }
821 if (current->signal & ~current->blocked) {
822 retval = -ERESTARTSYS;
823 break;
824 }
825 schedule();
826 continue;
827 }
828 current->state = TASK_RUNNING;
829
830
831 if (tty->packet && b == buf) {
832 put_fs_byte(TIOCPKT_DATA, b++);
833 nr--;
834 }
835
836 if (L_ICANON(tty)) {
837 while (1) {
838 int eol;
839
840 disable_bh(TQUEUE_BH);
841 if (!tty->read_cnt) {
842 enable_bh(TQUEUE_BH);
843 break;
844 }
845 eol = clear_bit(tty->read_tail,
846 &tty->read_flags);
847 c = tty->read_buf[tty->read_tail];
848 tty->read_tail = ((tty->read_tail+1) &
849 (N_TTY_BUF_SIZE-1));
850 tty->read_cnt--;
851 enable_bh(TQUEUE_BH);
852 if (!eol) {
853 put_fs_byte(c, b++);
854 if (--nr)
855 continue;
856 break;
857 }
858 if (--tty->canon_data < 0) {
859 tty->canon_data = 0;
860 }
861 if (c != __DISABLED_CHAR) {
862 put_fs_byte(c, b++);
863 nr--;
864 }
865 break;
866 }
867 } else {
868 disable_bh(TQUEUE_BH);
869 copy_from_read_buf(tty, &b, &nr);
870 copy_from_read_buf(tty, &b, &nr);
871 enable_bh(TQUEUE_BH);
872 }
873
874
875
876 if (tty->driver.unthrottle &&
877 (tty->read_cnt <= TTY_THRESHOLD_UNTHROTTLE)
878 && clear_bit(TTY_THROTTLED, &tty->flags))
879 tty->driver.unthrottle(tty);
880
881 if (b - buf >= minimum || !nr)
882 break;
883 if (time)
884 current->timeout = time + jiffies;
885 }
886 remove_wait_queue(&tty->read_wait, &wait);
887
888 if (!tty->read_wait)
889 tty->minimum_to_wake = minimum;
890
891 current->state = TASK_RUNNING;
892 current->timeout = 0;
893 size = b - buf;
894 if (size && nr)
895 clear_bit(TTY_PUSH, &tty->flags);
896 if (!size && clear_bit(TTY_PUSH, &tty->flags))
897 goto do_it_again;
898 if (!size && !retval)
899 clear_bit(TTY_PUSH, &tty->flags);
900 return (size ? size : retval);
901 }
902
903 static int write_chan(struct tty_struct * tty, struct file * file,
904 unsigned char * buf, unsigned int nr)
905 {
906 struct wait_queue wait = { current, NULL };
907 int c;
908 unsigned char *b = buf;
909 int retval = 0;
910
911
912 if (L_TOSTOP(tty) && file->f_inode->i_rdev != CONSOLE_DEV) {
913 retval = tty_check_change(tty);
914 if (retval)
915 return retval;
916 }
917
918 add_wait_queue(&tty->write_wait, &wait);
919 while (1) {
920 current->state = TASK_INTERRUPTIBLE;
921 if (current->signal & ~current->blocked) {
922 retval = -ERESTARTSYS;
923 break;
924 }
925 if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) {
926 retval = -EIO;
927 break;
928 }
929 if (O_OPOST(tty)) {
930 while (nr > 0) {
931 c = get_fs_byte(b);
932 if (opost(c, tty) < 0)
933 break;
934 b++; nr--;
935 }
936 if (tty->driver.flush_chars)
937 tty->driver.flush_chars(tty);
938 } else {
939 c = tty->driver.write(tty, 1, b, nr);
940 b += c;
941 nr -= c;
942 }
943 if (!nr)
944 break;
945 if (file->f_flags & O_NONBLOCK) {
946 retval = -EAGAIN;
947 break;
948 }
949 schedule();
950 }
951 current->state = TASK_RUNNING;
952 remove_wait_queue(&tty->write_wait, &wait);
953 return (b - buf) ? b - buf : retval;
954 }
955
956 static int normal_select(struct tty_struct * tty, struct inode * inode,
957 struct file * file, int sel_type, select_table *wait)
958 {
959 switch (sel_type) {
960 case SEL_IN:
961 if (input_available_p(tty, TIME_CHAR(tty) ? 0 :
962 MIN_CHAR(tty)))
963 return 1;
964
965 case SEL_EX:
966 if (tty->packet && tty->link->ctrl_status)
967 return 1;
968 if (tty->flags & (1 << TTY_SLAVE_CLOSED))
969 return 1;
970 if (tty_hung_up_p(file))
971 return 1;
972 if (!tty->read_wait) {
973 if (MIN_CHAR(tty) && !TIME_CHAR(tty))
974 tty->minimum_to_wake = MIN_CHAR(tty);
975 else
976 tty->minimum_to_wake = 1;
977 }
978 select_wait(&tty->read_wait, wait);
979 return 0;
980 case SEL_OUT:
981 if (tty->driver.chars_in_buffer(tty) < WAKEUP_CHARS)
982 return 1;
983 select_wait(&tty->write_wait, wait);
984 return 0;
985 }
986 return 0;
987 }
988
989 struct tty_ldisc tty_ldisc_N_TTY = {
990 TTY_LDISC_MAGIC,
991 0,
992 0,
993 n_tty_open,
994 n_tty_close,
995 n_tty_flush_buffer,
996 n_tty_chars_in_buffer,
997 read_chan,
998 write_chan,
999 n_tty_ioctl,
1000 n_tty_set_termios,
1001 normal_select,
1002 n_tty_receive_buf,
1003 n_tty_receive_room,
1004 0
1005 };
1006