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