Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/drivers/char/n_tty.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 39178 byte(s)
Tag kernel26-2.6.12-alx-r9
1 | /* |
2 | * n_tty.c --- implements the N_TTY line discipline. |
3 | * |
4 | * This code used to be in tty_io.c, but things are getting hairy |
5 | * enough that it made sense to split things off. (The N_TTY |
6 | * processing has changed so much that it's hardly recognizable, |
7 | * anyway...) |
8 | * |
9 | * Note that the open routine for N_TTY is guaranteed never to return |
10 | * an error. This is because Linux will fall back to setting a line |
11 | * to N_TTY if it can not switch to any other line discipline. |
12 | * |
13 | * Written by Theodore Ts'o, Copyright 1994. |
14 | * |
15 | * This file also contains code originally written by Linus Torvalds, |
16 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. |
17 | * |
18 | * This file may be redistributed under the terms of the GNU General Public |
19 | * License. |
20 | * |
21 | * Reduced memory usage for older ARM systems - Russell King. |
22 | * |
23 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
24 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
25 | * who actually finally proved there really was a race. |
26 | * |
27 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to |
28 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. |
29 | * Also fixed a bug in BLOCKING mode where write_chan returns |
30 | * EAGAIN |
31 | */ |
32 | |
33 | #include <linux/types.h> |
34 | #include <linux/major.h> |
35 | #include <linux/errno.h> |
36 | #include <linux/signal.h> |
37 | #include <linux/fcntl.h> |
38 | #include <linux/sched.h> |
39 | #include <linux/interrupt.h> |
40 | #include <linux/tty.h> |
41 | #include <linux/timer.h> |
42 | #include <linux/ctype.h> |
43 | #include <linux/mm.h> |
44 | #include <linux/string.h> |
45 | #include <linux/slab.h> |
46 | #include <linux/poll.h> |
47 | #include <linux/bitops.h> |
48 | |
49 | #include <asm/uaccess.h> |
50 | #include <asm/system.h> |
51 | |
52 | /* number of characters left in xmit buffer before select has we have room */ |
53 | #define WAKEUP_CHARS 256 |
54 | |
55 | /* |
56 | * This defines the low- and high-watermarks for throttling and |
57 | * unthrottling the TTY driver. These watermarks are used for |
58 | * controlling the space in the read buffer. |
59 | */ |
60 | #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ |
61 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
62 | |
63 | static inline unsigned char *alloc_buf(void) |
64 | { |
65 | int prio = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL; |
66 | |
67 | if (PAGE_SIZE != N_TTY_BUF_SIZE) |
68 | return kmalloc(N_TTY_BUF_SIZE, prio); |
69 | else |
70 | return (unsigned char *)__get_free_page(prio); |
71 | } |
72 | |
73 | static inline void free_buf(unsigned char *buf) |
74 | { |
75 | if (PAGE_SIZE != N_TTY_BUF_SIZE) |
76 | kfree(buf); |
77 | else |
78 | free_page((unsigned long) buf); |
79 | } |
80 | |
81 | static inline void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty) |
82 | { |
83 | if (tty->read_cnt < N_TTY_BUF_SIZE) { |
84 | tty->read_buf[tty->read_head] = c; |
85 | tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1); |
86 | tty->read_cnt++; |
87 | } |
88 | } |
89 | |
90 | static inline void put_tty_queue(unsigned char c, struct tty_struct *tty) |
91 | { |
92 | unsigned long flags; |
93 | /* |
94 | * The problem of stomping on the buffers ends here. |
95 | * Why didn't anyone see this one coming? --AJK |
96 | */ |
97 | spin_lock_irqsave(&tty->read_lock, flags); |
98 | put_tty_queue_nolock(c, tty); |
99 | spin_unlock_irqrestore(&tty->read_lock, flags); |
100 | } |
101 | |
102 | /** |
103 | * check_unthrottle - allow new receive data |
104 | * @tty; tty device |
105 | * |
106 | * Check whether to call the driver.unthrottle function. |
107 | * We test the TTY_THROTTLED bit first so that it always |
108 | * indicates the current state. The decision about whether |
109 | * it is worth allowing more input has been taken by the caller. |
110 | * Can sleep, may be called under the atomic_read semaphore but |
111 | * this is not guaranteed. |
112 | */ |
113 | |
114 | static void check_unthrottle(struct tty_struct * tty) |
115 | { |
116 | if (tty->count && |
117 | test_and_clear_bit(TTY_THROTTLED, &tty->flags) && |
118 | tty->driver->unthrottle) |
119 | tty->driver->unthrottle(tty); |
120 | } |
121 | |
122 | /** |
123 | * reset_buffer_flags - reset buffer state |
124 | * @tty: terminal to reset |
125 | * |
126 | * Reset the read buffer counters, clear the flags, |
127 | * and make sure the driver is unthrottled. Called |
128 | * from n_tty_open() and n_tty_flush_buffer(). |
129 | */ |
130 | static void reset_buffer_flags(struct tty_struct *tty) |
131 | { |
132 | unsigned long flags; |
133 | |
134 | spin_lock_irqsave(&tty->read_lock, flags); |
135 | tty->read_head = tty->read_tail = tty->read_cnt = 0; |
136 | spin_unlock_irqrestore(&tty->read_lock, flags); |
137 | tty->canon_head = tty->canon_data = tty->erasing = 0; |
138 | memset(&tty->read_flags, 0, sizeof tty->read_flags); |
139 | check_unthrottle(tty); |
140 | } |
141 | |
142 | /** |
143 | * n_tty_flush_buffer - clean input queue |
144 | * @tty: terminal device |
145 | * |
146 | * Flush the input buffer. Called when the line discipline is |
147 | * being closed, when the tty layer wants the buffer flushed (eg |
148 | * at hangup) or when the N_TTY line discipline internally has to |
149 | * clean the pending queue (for example some signals). |
150 | * |
151 | * FIXME: tty->ctrl_status is not spinlocked and relies on |
152 | * lock_kernel() still. |
153 | */ |
154 | |
155 | static void n_tty_flush_buffer(struct tty_struct * tty) |
156 | { |
157 | /* clear everything and unthrottle the driver */ |
158 | reset_buffer_flags(tty); |
159 | |
160 | if (!tty->link) |
161 | return; |
162 | |
163 | if (tty->link->packet) { |
164 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; |
165 | wake_up_interruptible(&tty->link->read_wait); |
166 | } |
167 | } |
168 | |
169 | /** |
170 | * n_tty_chars_in_buffer - report available bytes |
171 | * @tty: tty device |
172 | * |
173 | * Report the number of characters buffered to be delivered to user |
174 | * at this instant in time. |
175 | */ |
176 | |
177 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
178 | { |
179 | unsigned long flags; |
180 | ssize_t n = 0; |
181 | |
182 | spin_lock_irqsave(&tty->read_lock, flags); |
183 | if (!tty->icanon) { |
184 | n = tty->read_cnt; |
185 | } else if (tty->canon_data) { |
186 | n = (tty->canon_head > tty->read_tail) ? |
187 | tty->canon_head - tty->read_tail : |
188 | tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail); |
189 | } |
190 | spin_unlock_irqrestore(&tty->read_lock, flags); |
191 | return n; |
192 | } |
193 | |
194 | /** |
195 | * is_utf8_continuation - utf8 multibyte check |
196 | * @c: byte to check |
197 | * |
198 | * Returns true if the utf8 character 'c' is a multibyte continuation |
199 | * character. We use this to correctly compute the on screen size |
200 | * of the character when printing |
201 | */ |
202 | |
203 | static inline int is_utf8_continuation(unsigned char c) |
204 | { |
205 | return (c & 0xc0) == 0x80; |
206 | } |
207 | |
208 | /** |
209 | * is_continuation - multibyte check |
210 | * @c: byte to check |
211 | * |
212 | * Returns true if the utf8 character 'c' is a multibyte continuation |
213 | * character and the terminal is in unicode mode. |
214 | */ |
215 | |
216 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
217 | { |
218 | return I_IUTF8(tty) && is_utf8_continuation(c); |
219 | } |
220 | |
221 | /** |
222 | * opost - output post processor |
223 | * @c: character (or partial unicode symbol) |
224 | * @tty: terminal device |
225 | * |
226 | * Perform OPOST processing. Returns -1 when the output device is |
227 | * full and the character must be retried. Note that Linux currently |
228 | * ignores TABDLY, CRDLY, VTDLY, FFDLY and NLDLY. They simply aren't |
229 | * relevant in the world today. If you ever need them, add them here. |
230 | * |
231 | * Called from both the receive and transmit sides and can be called |
232 | * re-entrantly. Relies on lock_kernel() still. |
233 | */ |
234 | |
235 | static int opost(unsigned char c, struct tty_struct *tty) |
236 | { |
237 | int space, spaces; |
238 | |
239 | space = tty->driver->write_room(tty); |
240 | if (!space) |
241 | return -1; |
242 | |
243 | if (O_OPOST(tty)) { |
244 | switch (c) { |
245 | case '\n': |
246 | if (O_ONLRET(tty)) |
247 | tty->column = 0; |
248 | if (O_ONLCR(tty)) { |
249 | if (space < 2) |
250 | return -1; |
251 | tty->driver->put_char(tty, '\r'); |
252 | tty->column = 0; |
253 | } |
254 | tty->canon_column = tty->column; |
255 | break; |
256 | case '\r': |
257 | if (O_ONOCR(tty) && tty->column == 0) |
258 | return 0; |
259 | if (O_OCRNL(tty)) { |
260 | c = '\n'; |
261 | if (O_ONLRET(tty)) |
262 | tty->canon_column = tty->column = 0; |
263 | break; |
264 | } |
265 | tty->canon_column = tty->column = 0; |
266 | break; |
267 | case '\t': |
268 | spaces = 8 - (tty->column & 7); |
269 | if (O_TABDLY(tty) == XTABS) { |
270 | if (space < spaces) |
271 | return -1; |
272 | tty->column += spaces; |
273 | tty->driver->write(tty, " ", spaces); |
274 | return 0; |
275 | } |
276 | tty->column += spaces; |
277 | break; |
278 | case '\b': |
279 | if (tty->column > 0) |
280 | tty->column--; |
281 | break; |
282 | default: |
283 | if (O_OLCUC(tty)) |
284 | c = toupper(c); |
285 | if (!iscntrl(c) && !is_continuation(c, tty)) |
286 | tty->column++; |
287 | break; |
288 | } |
289 | } |
290 | tty->driver->put_char(tty, c); |
291 | return 0; |
292 | } |
293 | |
294 | /** |
295 | * opost_block - block postprocess |
296 | * @tty: terminal device |
297 | * @inbuf: user buffer |
298 | * @nr: number of bytes |
299 | * |
300 | * This path is used to speed up block console writes, among other |
301 | * things when processing blocks of output data. It handles only |
302 | * the simple cases normally found and helps to generate blocks of |
303 | * symbols for the console driver and thus improve performance. |
304 | * |
305 | * Called from write_chan under the tty layer write lock. |
306 | */ |
307 | |
308 | static ssize_t opost_block(struct tty_struct * tty, |
309 | const unsigned char * buf, unsigned int nr) |
310 | { |
311 | int space; |
312 | int i; |
313 | const unsigned char *cp; |
314 | |
315 | space = tty->driver->write_room(tty); |
316 | if (!space) |
317 | return 0; |
318 | if (nr > space) |
319 | nr = space; |
320 | |
321 | for (i = 0, cp = buf; i < nr; i++, cp++) { |
322 | switch (*cp) { |
323 | case '\n': |
324 | if (O_ONLRET(tty)) |
325 | tty->column = 0; |
326 | if (O_ONLCR(tty)) |
327 | goto break_out; |
328 | tty->canon_column = tty->column; |
329 | break; |
330 | case '\r': |
331 | if (O_ONOCR(tty) && tty->column == 0) |
332 | goto break_out; |
333 | if (O_OCRNL(tty)) |
334 | goto break_out; |
335 | tty->canon_column = tty->column = 0; |
336 | break; |
337 | case '\t': |
338 | goto break_out; |
339 | case '\b': |
340 | if (tty->column > 0) |
341 | tty->column--; |
342 | break; |
343 | default: |
344 | if (O_OLCUC(tty)) |
345 | goto break_out; |
346 | if (!iscntrl(*cp)) |
347 | tty->column++; |
348 | break; |
349 | } |
350 | } |
351 | break_out: |
352 | if (tty->driver->flush_chars) |
353 | tty->driver->flush_chars(tty); |
354 | i = tty->driver->write(tty, buf, i); |
355 | return i; |
356 | } |
357 | |
358 | |
359 | /** |
360 | * put_char - write character to driver |
361 | * @c: character (or part of unicode symbol) |
362 | * @tty: terminal device |
363 | * |
364 | * Queue a byte to the driver layer for output |
365 | */ |
366 | |
367 | static inline void put_char(unsigned char c, struct tty_struct *tty) |
368 | { |
369 | tty->driver->put_char(tty, c); |
370 | } |
371 | |
372 | /** |
373 | * echo_char - echo characters |
374 | * @c: unicode byte to echo |
375 | * @tty: terminal device |
376 | * |
377 | * Echo user input back onto the screen. This must be called only when |
378 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
379 | */ |
380 | |
381 | static void echo_char(unsigned char c, struct tty_struct *tty) |
382 | { |
383 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') { |
384 | put_char('^', tty); |
385 | put_char(c ^ 0100, tty); |
386 | tty->column += 2; |
387 | } else |
388 | opost(c, tty); |
389 | } |
390 | |
391 | static inline void finish_erasing(struct tty_struct *tty) |
392 | { |
393 | if (tty->erasing) { |
394 | put_char('/', tty); |
395 | tty->column++; |
396 | tty->erasing = 0; |
397 | } |
398 | } |
399 | |
400 | /** |
401 | * eraser - handle erase function |
402 | * @c: character input |
403 | * @tty: terminal device |
404 | * |
405 | * Perform erase and neccessary output when an erase character is |
406 | * present in the stream from the driver layer. Handles the complexities |
407 | * of UTF-8 multibyte symbols. |
408 | */ |
409 | |
410 | static void eraser(unsigned char c, struct tty_struct *tty) |
411 | { |
412 | enum { ERASE, WERASE, KILL } kill_type; |
413 | int head, seen_alnums, cnt; |
414 | unsigned long flags; |
415 | |
416 | if (tty->read_head == tty->canon_head) { |
417 | /* opost('\a', tty); */ /* what do you think? */ |
418 | return; |
419 | } |
420 | if (c == ERASE_CHAR(tty)) |
421 | kill_type = ERASE; |
422 | else if (c == WERASE_CHAR(tty)) |
423 | kill_type = WERASE; |
424 | else { |
425 | if (!L_ECHO(tty)) { |
426 | spin_lock_irqsave(&tty->read_lock, flags); |
427 | tty->read_cnt -= ((tty->read_head - tty->canon_head) & |
428 | (N_TTY_BUF_SIZE - 1)); |
429 | tty->read_head = tty->canon_head; |
430 | spin_unlock_irqrestore(&tty->read_lock, flags); |
431 | return; |
432 | } |
433 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { |
434 | spin_lock_irqsave(&tty->read_lock, flags); |
435 | tty->read_cnt -= ((tty->read_head - tty->canon_head) & |
436 | (N_TTY_BUF_SIZE - 1)); |
437 | tty->read_head = tty->canon_head; |
438 | spin_unlock_irqrestore(&tty->read_lock, flags); |
439 | finish_erasing(tty); |
440 | echo_char(KILL_CHAR(tty), tty); |
441 | /* Add a newline if ECHOK is on and ECHOKE is off. */ |
442 | if (L_ECHOK(tty)) |
443 | opost('\n', tty); |
444 | return; |
445 | } |
446 | kill_type = KILL; |
447 | } |
448 | |
449 | seen_alnums = 0; |
450 | while (tty->read_head != tty->canon_head) { |
451 | head = tty->read_head; |
452 | |
453 | /* erase a single possibly multibyte character */ |
454 | do { |
455 | head = (head - 1) & (N_TTY_BUF_SIZE-1); |
456 | c = tty->read_buf[head]; |
457 | } while (is_continuation(c, tty) && head != tty->canon_head); |
458 | |
459 | /* do not partially erase */ |
460 | if (is_continuation(c, tty)) |
461 | break; |
462 | |
463 | if (kill_type == WERASE) { |
464 | /* Equivalent to BSD's ALTWERASE. */ |
465 | if (isalnum(c) || c == '_') |
466 | seen_alnums++; |
467 | else if (seen_alnums) |
468 | break; |
469 | } |
470 | cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1); |
471 | spin_lock_irqsave(&tty->read_lock, flags); |
472 | tty->read_head = head; |
473 | tty->read_cnt -= cnt; |
474 | spin_unlock_irqrestore(&tty->read_lock, flags); |
475 | if (L_ECHO(tty)) { |
476 | if (L_ECHOPRT(tty)) { |
477 | if (!tty->erasing) { |
478 | put_char('\\', tty); |
479 | tty->column++; |
480 | tty->erasing = 1; |
481 | } |
482 | /* if cnt > 1, output a multi-byte character */ |
483 | echo_char(c, tty); |
484 | while (--cnt > 0) { |
485 | head = (head+1) & (N_TTY_BUF_SIZE-1); |
486 | put_char(tty->read_buf[head], tty); |
487 | } |
488 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { |
489 | echo_char(ERASE_CHAR(tty), tty); |
490 | } else if (c == '\t') { |
491 | unsigned int col = tty->canon_column; |
492 | unsigned long tail = tty->canon_head; |
493 | |
494 | /* Find the column of the last char. */ |
495 | while (tail != tty->read_head) { |
496 | c = tty->read_buf[tail]; |
497 | if (c == '\t') |
498 | col = (col | 7) + 1; |
499 | else if (iscntrl(c)) { |
500 | if (L_ECHOCTL(tty)) |
501 | col += 2; |
502 | } else if (!is_continuation(c, tty)) |
503 | col++; |
504 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); |
505 | } |
506 | |
507 | /* should never happen */ |
508 | if (tty->column > 0x80000000) |
509 | tty->column = 0; |
510 | |
511 | /* Now backup to that column. */ |
512 | while (tty->column > col) { |
513 | /* Can't use opost here. */ |
514 | put_char('\b', tty); |
515 | if (tty->column > 0) |
516 | tty->column--; |
517 | } |
518 | } else { |
519 | if (iscntrl(c) && L_ECHOCTL(tty)) { |
520 | put_char('\b', tty); |
521 | put_char(' ', tty); |
522 | put_char('\b', tty); |
523 | if (tty->column > 0) |
524 | tty->column--; |
525 | } |
526 | if (!iscntrl(c) || L_ECHOCTL(tty)) { |
527 | put_char('\b', tty); |
528 | put_char(' ', tty); |
529 | put_char('\b', tty); |
530 | if (tty->column > 0) |
531 | tty->column--; |
532 | } |
533 | } |
534 | } |
535 | if (kill_type == ERASE) |
536 | break; |
537 | } |
538 | if (tty->read_head == tty->canon_head) |
539 | finish_erasing(tty); |
540 | } |
541 | |
542 | /** |
543 | * isig - handle the ISIG optio |
544 | * @sig: signal |
545 | * @tty: terminal |
546 | * @flush: force flush |
547 | * |
548 | * Called when a signal is being sent due to terminal input. This |
549 | * may caus terminal flushing to take place according to the termios |
550 | * settings and character used. Called from the driver receive_buf |
551 | * path so serialized. |
552 | */ |
553 | |
554 | static inline void isig(int sig, struct tty_struct *tty, int flush) |
555 | { |
556 | if (tty->pgrp > 0) |
557 | kill_pg(tty->pgrp, sig, 1); |
558 | if (flush || !L_NOFLSH(tty)) { |
559 | n_tty_flush_buffer(tty); |
560 | if (tty->driver->flush_buffer) |
561 | tty->driver->flush_buffer(tty); |
562 | } |
563 | } |
564 | |
565 | /** |
566 | * n_tty_receive_break - handle break |
567 | * @tty: terminal |
568 | * |
569 | * An RS232 break event has been hit in the incoming bitstream. This |
570 | * can cause a variety of events depending upon the termios settings. |
571 | * |
572 | * Called from the receive_buf path so single threaded. |
573 | */ |
574 | |
575 | static inline void n_tty_receive_break(struct tty_struct *tty) |
576 | { |
577 | if (I_IGNBRK(tty)) |
578 | return; |
579 | if (I_BRKINT(tty)) { |
580 | isig(SIGINT, tty, 1); |
581 | return; |
582 | } |
583 | if (I_PARMRK(tty)) { |
584 | put_tty_queue('\377', tty); |
585 | put_tty_queue('\0', tty); |
586 | } |
587 | put_tty_queue('\0', tty); |
588 | wake_up_interruptible(&tty->read_wait); |
589 | } |
590 | |
591 | /** |
592 | * n_tty_receive_overrun - handle overrun reporting |
593 | * @tty: terminal |
594 | * |
595 | * Data arrived faster than we could process it. While the tty |
596 | * driver has flagged this the bits that were missed are gone |
597 | * forever. |
598 | * |
599 | * Called from the receive_buf path so single threaded. Does not |
600 | * need locking as num_overrun and overrun_time are function |
601 | * private. |
602 | */ |
603 | |
604 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
605 | { |
606 | char buf[64]; |
607 | |
608 | tty->num_overrun++; |
609 | if (time_before(tty->overrun_time, jiffies - HZ) || |
610 | time_after(tty->overrun_time, jiffies)) { |
611 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
612 | tty_name(tty, buf), |
613 | tty->num_overrun); |
614 | tty->overrun_time = jiffies; |
615 | tty->num_overrun = 0; |
616 | } |
617 | } |
618 | |
619 | /** |
620 | * n_tty_receive_parity_error - error notifier |
621 | * @tty: terminal device |
622 | * @c: character |
623 | * |
624 | * Process a parity error and queue the right data to indicate |
625 | * the error case if neccessary. Locking as per n_tty_receive_buf. |
626 | */ |
627 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, |
628 | unsigned char c) |
629 | { |
630 | if (I_IGNPAR(tty)) { |
631 | return; |
632 | } |
633 | if (I_PARMRK(tty)) { |
634 | put_tty_queue('\377', tty); |
635 | put_tty_queue('\0', tty); |
636 | put_tty_queue(c, tty); |
637 | } else if (I_INPCK(tty)) |
638 | put_tty_queue('\0', tty); |
639 | else |
640 | put_tty_queue(c, tty); |
641 | wake_up_interruptible(&tty->read_wait); |
642 | } |
643 | |
644 | /** |
645 | * n_tty_receive_char - perform processing |
646 | * @tty: terminal device |
647 | * @c: character |
648 | * |
649 | * Process an individual character of input received from the driver. |
650 | * This is serialized with respect to itself by the rules for the |
651 | * driver above. |
652 | */ |
653 | |
654 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
655 | { |
656 | unsigned long flags; |
657 | |
658 | if (tty->raw) { |
659 | put_tty_queue(c, tty); |
660 | return; |
661 | } |
662 | |
663 | if (tty->stopped && !tty->flow_stopped && |
664 | I_IXON(tty) && I_IXANY(tty)) { |
665 | start_tty(tty); |
666 | return; |
667 | } |
668 | |
669 | if (I_ISTRIP(tty)) |
670 | c &= 0x7f; |
671 | if (I_IUCLC(tty) && L_IEXTEN(tty)) |
672 | c=tolower(c); |
673 | |
674 | if (tty->closing) { |
675 | if (I_IXON(tty)) { |
676 | if (c == START_CHAR(tty)) |
677 | start_tty(tty); |
678 | else if (c == STOP_CHAR(tty)) |
679 | stop_tty(tty); |
680 | } |
681 | return; |
682 | } |
683 | |
684 | /* |
685 | * If the previous character was LNEXT, or we know that this |
686 | * character is not one of the characters that we'll have to |
687 | * handle specially, do shortcut processing to speed things |
688 | * up. |
689 | */ |
690 | if (!test_bit(c, tty->process_char_map) || tty->lnext) { |
691 | finish_erasing(tty); |
692 | tty->lnext = 0; |
693 | if (L_ECHO(tty)) { |
694 | if (tty->read_cnt >= N_TTY_BUF_SIZE-1) { |
695 | put_char('\a', tty); /* beep if no space */ |
696 | return; |
697 | } |
698 | /* Record the column of first canon char. */ |
699 | if (tty->canon_head == tty->read_head) |
700 | tty->canon_column = tty->column; |
701 | echo_char(c, tty); |
702 | } |
703 | if (I_PARMRK(tty) && c == (unsigned char) '\377') |
704 | put_tty_queue(c, tty); |
705 | put_tty_queue(c, tty); |
706 | return; |
707 | } |
708 | |
709 | if (c == '\r') { |
710 | if (I_IGNCR(tty)) |
711 | return; |
712 | if (I_ICRNL(tty)) |
713 | c = '\n'; |
714 | } else if (c == '\n' && I_INLCR(tty)) |
715 | c = '\r'; |
716 | if (I_IXON(tty)) { |
717 | if (c == START_CHAR(tty)) { |
718 | start_tty(tty); |
719 | return; |
720 | } |
721 | if (c == STOP_CHAR(tty)) { |
722 | stop_tty(tty); |
723 | return; |
724 | } |
725 | } |
726 | if (L_ISIG(tty)) { |
727 | int signal; |
728 | signal = SIGINT; |
729 | if (c == INTR_CHAR(tty)) |
730 | goto send_signal; |
731 | signal = SIGQUIT; |
732 | if (c == QUIT_CHAR(tty)) |
733 | goto send_signal; |
734 | signal = SIGTSTP; |
735 | if (c == SUSP_CHAR(tty)) { |
736 | send_signal: |
737 | isig(signal, tty, 0); |
738 | return; |
739 | } |
740 | } |
741 | if (tty->icanon) { |
742 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
743 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { |
744 | eraser(c, tty); |
745 | return; |
746 | } |
747 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { |
748 | tty->lnext = 1; |
749 | if (L_ECHO(tty)) { |
750 | finish_erasing(tty); |
751 | if (L_ECHOCTL(tty)) { |
752 | put_char('^', tty); |
753 | put_char('\b', tty); |
754 | } |
755 | } |
756 | return; |
757 | } |
758 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && |
759 | L_IEXTEN(tty)) { |
760 | unsigned long tail = tty->canon_head; |
761 | |
762 | finish_erasing(tty); |
763 | echo_char(c, tty); |
764 | opost('\n', tty); |
765 | while (tail != tty->read_head) { |
766 | echo_char(tty->read_buf[tail], tty); |
767 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); |
768 | } |
769 | return; |
770 | } |
771 | if (c == '\n') { |
772 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
773 | if (tty->read_cnt >= N_TTY_BUF_SIZE-1) { |
774 | put_char('\a', tty); |
775 | return; |
776 | } |
777 | opost('\n', tty); |
778 | } |
779 | goto handle_newline; |
780 | } |
781 | if (c == EOF_CHAR(tty)) { |
782 | if (tty->canon_head != tty->read_head) |
783 | set_bit(TTY_PUSH, &tty->flags); |
784 | c = __DISABLED_CHAR; |
785 | goto handle_newline; |
786 | } |
787 | if ((c == EOL_CHAR(tty)) || |
788 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { |
789 | /* |
790 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? |
791 | */ |
792 | if (L_ECHO(tty)) { |
793 | if (tty->read_cnt >= N_TTY_BUF_SIZE-1) { |
794 | put_char('\a', tty); |
795 | return; |
796 | } |
797 | /* Record the column of first canon char. */ |
798 | if (tty->canon_head == tty->read_head) |
799 | tty->canon_column = tty->column; |
800 | echo_char(c, tty); |
801 | } |
802 | /* |
803 | * XXX does PARMRK doubling happen for |
804 | * EOL_CHAR and EOL2_CHAR? |
805 | */ |
806 | if (I_PARMRK(tty) && c == (unsigned char) '\377') |
807 | put_tty_queue(c, tty); |
808 | |
809 | handle_newline: |
810 | spin_lock_irqsave(&tty->read_lock, flags); |
811 | set_bit(tty->read_head, tty->read_flags); |
812 | put_tty_queue_nolock(c, tty); |
813 | tty->canon_head = tty->read_head; |
814 | tty->canon_data++; |
815 | spin_unlock_irqrestore(&tty->read_lock, flags); |
816 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
817 | if (waitqueue_active(&tty->read_wait)) |
818 | wake_up_interruptible(&tty->read_wait); |
819 | return; |
820 | } |
821 | } |
822 | |
823 | finish_erasing(tty); |
824 | if (L_ECHO(tty)) { |
825 | if (tty->read_cnt >= N_TTY_BUF_SIZE-1) { |
826 | put_char('\a', tty); /* beep if no space */ |
827 | return; |
828 | } |
829 | if (c == '\n') |
830 | opost('\n', tty); |
831 | else { |
832 | /* Record the column of first canon char. */ |
833 | if (tty->canon_head == tty->read_head) |
834 | tty->canon_column = tty->column; |
835 | echo_char(c, tty); |
836 | } |
837 | } |
838 | |
839 | if (I_PARMRK(tty) && c == (unsigned char) '\377') |
840 | put_tty_queue(c, tty); |
841 | |
842 | put_tty_queue(c, tty); |
843 | } |
844 | |
845 | /** |
846 | * n_tty_receive_room - receive space |
847 | * @tty: terminal |
848 | * |
849 | * Called by the driver to find out how much data it is |
850 | * permitted to feed to the line discipline without any being lost |
851 | * and thus to manage flow control. Not serialized. Answers for the |
852 | * "instant". |
853 | */ |
854 | |
855 | static int n_tty_receive_room(struct tty_struct *tty) |
856 | { |
857 | int left = N_TTY_BUF_SIZE - tty->read_cnt - 1; |
858 | |
859 | /* |
860 | * If we are doing input canonicalization, and there are no |
861 | * pending newlines, let characters through without limit, so |
862 | * that erase characters will be handled. Other excess |
863 | * characters will be beeped. |
864 | */ |
865 | if (tty->icanon && !tty->canon_data) |
866 | return N_TTY_BUF_SIZE; |
867 | |
868 | if (left > 0) |
869 | return left; |
870 | return 0; |
871 | } |
872 | |
873 | /** |
874 | * n_tty_write_wakeup - asynchronous I/O notifier |
875 | * @tty: tty device |
876 | * |
877 | * Required for the ptys, serial driver etc. since processes |
878 | * that attach themselves to the master and rely on ASYNC |
879 | * IO must be woken up |
880 | */ |
881 | |
882 | static void n_tty_write_wakeup(struct tty_struct *tty) |
883 | { |
884 | if (tty->fasync) |
885 | { |
886 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
887 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); |
888 | } |
889 | return; |
890 | } |
891 | |
892 | /** |
893 | * n_tty_receive_buf - data receive |
894 | * @tty: terminal device |
895 | * @cp: buffer |
896 | * @fp: flag buffer |
897 | * @count: characters |
898 | * |
899 | * Called by the terminal driver when a block of characters has |
900 | * been received. This function must be called from soft contexts |
901 | * not from interrupt context. The driver is responsible for making |
902 | * calls one at a time and in order (or using flush_to_ldisc) |
903 | */ |
904 | |
905 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
906 | char *fp, int count) |
907 | { |
908 | const unsigned char *p; |
909 | char *f, flags = TTY_NORMAL; |
910 | int i; |
911 | char buf[64]; |
912 | unsigned long cpuflags; |
913 | |
914 | if (!tty->read_buf) |
915 | return; |
916 | |
917 | if (tty->real_raw) { |
918 | spin_lock_irqsave(&tty->read_lock, cpuflags); |
919 | i = min(N_TTY_BUF_SIZE - tty->read_cnt, |
920 | N_TTY_BUF_SIZE - tty->read_head); |
921 | i = min(count, i); |
922 | memcpy(tty->read_buf + tty->read_head, cp, i); |
923 | tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); |
924 | tty->read_cnt += i; |
925 | cp += i; |
926 | count -= i; |
927 | |
928 | i = min(N_TTY_BUF_SIZE - tty->read_cnt, |
929 | N_TTY_BUF_SIZE - tty->read_head); |
930 | i = min(count, i); |
931 | memcpy(tty->read_buf + tty->read_head, cp, i); |
932 | tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); |
933 | tty->read_cnt += i; |
934 | spin_unlock_irqrestore(&tty->read_lock, cpuflags); |
935 | } else { |
936 | for (i=count, p = cp, f = fp; i; i--, p++) { |
937 | if (f) |
938 | flags = *f++; |
939 | switch (flags) { |
940 | case TTY_NORMAL: |
941 | n_tty_receive_char(tty, *p); |
942 | break; |
943 | case TTY_BREAK: |
944 | n_tty_receive_break(tty); |
945 | break; |
946 | case TTY_PARITY: |
947 | case TTY_FRAME: |
948 | n_tty_receive_parity_error(tty, *p); |
949 | break; |
950 | case TTY_OVERRUN: |
951 | n_tty_receive_overrun(tty); |
952 | break; |
953 | default: |
954 | printk("%s: unknown flag %d\n", |
955 | tty_name(tty, buf), flags); |
956 | break; |
957 | } |
958 | } |
959 | if (tty->driver->flush_chars) |
960 | tty->driver->flush_chars(tty); |
961 | } |
962 | |
963 | if (!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) { |
964 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
965 | if (waitqueue_active(&tty->read_wait)) |
966 | wake_up_interruptible(&tty->read_wait); |
967 | } |
968 | |
969 | /* |
970 | * Check the remaining room for the input canonicalization |
971 | * mode. We don't want to throttle the driver if we're in |
972 | * canonical mode and don't have a newline yet! |
973 | */ |
974 | if (n_tty_receive_room(tty) < TTY_THRESHOLD_THROTTLE) { |
975 | /* check TTY_THROTTLED first so it indicates our state */ |
976 | if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) && |
977 | tty->driver->throttle) |
978 | tty->driver->throttle(tty); |
979 | } |
980 | } |
981 | |
982 | int is_ignored(int sig) |
983 | { |
984 | return (sigismember(¤t->blocked, sig) || |
985 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
986 | } |
987 | |
988 | /** |
989 | * n_tty_set_termios - termios data changed |
990 | * @tty: terminal |
991 | * @old: previous data |
992 | * |
993 | * Called by the tty layer when the user changes termios flags so |
994 | * that the line discipline can plan ahead. This function cannot sleep |
995 | * and is protected from re-entry by the tty layer. The user is |
996 | * guaranteed that this function will not be re-entered or in progress |
997 | * when the ldisc is closed. |
998 | */ |
999 | |
1000 | static void n_tty_set_termios(struct tty_struct *tty, struct termios * old) |
1001 | { |
1002 | if (!tty) |
1003 | return; |
1004 | |
1005 | tty->icanon = (L_ICANON(tty) != 0); |
1006 | if (test_bit(TTY_HW_COOK_IN, &tty->flags)) { |
1007 | tty->raw = 1; |
1008 | tty->real_raw = 1; |
1009 | return; |
1010 | } |
1011 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1012 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || |
1013 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || |
1014 | I_PARMRK(tty)) { |
1015 | memset(tty->process_char_map, 0, 256/8); |
1016 | |
1017 | if (I_IGNCR(tty) || I_ICRNL(tty)) |
1018 | set_bit('\r', tty->process_char_map); |
1019 | if (I_INLCR(tty)) |
1020 | set_bit('\n', tty->process_char_map); |
1021 | |
1022 | if (L_ICANON(tty)) { |
1023 | set_bit(ERASE_CHAR(tty), tty->process_char_map); |
1024 | set_bit(KILL_CHAR(tty), tty->process_char_map); |
1025 | set_bit(EOF_CHAR(tty), tty->process_char_map); |
1026 | set_bit('\n', tty->process_char_map); |
1027 | set_bit(EOL_CHAR(tty), tty->process_char_map); |
1028 | if (L_IEXTEN(tty)) { |
1029 | set_bit(WERASE_CHAR(tty), |
1030 | tty->process_char_map); |
1031 | set_bit(LNEXT_CHAR(tty), |
1032 | tty->process_char_map); |
1033 | set_bit(EOL2_CHAR(tty), |
1034 | tty->process_char_map); |
1035 | if (L_ECHO(tty)) |
1036 | set_bit(REPRINT_CHAR(tty), |
1037 | tty->process_char_map); |
1038 | } |
1039 | } |
1040 | if (I_IXON(tty)) { |
1041 | set_bit(START_CHAR(tty), tty->process_char_map); |
1042 | set_bit(STOP_CHAR(tty), tty->process_char_map); |
1043 | } |
1044 | if (L_ISIG(tty)) { |
1045 | set_bit(INTR_CHAR(tty), tty->process_char_map); |
1046 | set_bit(QUIT_CHAR(tty), tty->process_char_map); |
1047 | set_bit(SUSP_CHAR(tty), tty->process_char_map); |
1048 | } |
1049 | clear_bit(__DISABLED_CHAR, tty->process_char_map); |
1050 | tty->raw = 0; |
1051 | tty->real_raw = 0; |
1052 | } else { |
1053 | tty->raw = 1; |
1054 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1055 | (I_IGNPAR(tty) || !I_INPCK(tty)) && |
1056 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) |
1057 | tty->real_raw = 1; |
1058 | else |
1059 | tty->real_raw = 0; |
1060 | } |
1061 | } |
1062 | |
1063 | /** |
1064 | * n_tty_close - close the ldisc for this tty |
1065 | * @tty: device |
1066 | * |
1067 | * Called from the terminal layer when this line discipline is |
1068 | * being shut down, either because of a close or becsuse of a |
1069 | * discipline change. The function will not be called while other |
1070 | * ldisc methods are in progress. |
1071 | */ |
1072 | |
1073 | static void n_tty_close(struct tty_struct *tty) |
1074 | { |
1075 | n_tty_flush_buffer(tty); |
1076 | if (tty->read_buf) { |
1077 | free_buf(tty->read_buf); |
1078 | tty->read_buf = NULL; |
1079 | } |
1080 | } |
1081 | |
1082 | /** |
1083 | * n_tty_open - open an ldisc |
1084 | * @tty: terminal to open |
1085 | * |
1086 | * Called when this line discipline is being attached to the |
1087 | * terminal device. Can sleep. Called serialized so that no |
1088 | * other events will occur in parallel. No further open will occur |
1089 | * until a close. |
1090 | */ |
1091 | |
1092 | static int n_tty_open(struct tty_struct *tty) |
1093 | { |
1094 | if (!tty) |
1095 | return -EINVAL; |
1096 | |
1097 | /* This one is ugly. Currently a malloc failure here can panic */ |
1098 | if (!tty->read_buf) { |
1099 | tty->read_buf = alloc_buf(); |
1100 | if (!tty->read_buf) |
1101 | return -ENOMEM; |
1102 | } |
1103 | memset(tty->read_buf, 0, N_TTY_BUF_SIZE); |
1104 | reset_buffer_flags(tty); |
1105 | tty->column = 0; |
1106 | n_tty_set_termios(tty, NULL); |
1107 | tty->minimum_to_wake = 1; |
1108 | tty->closing = 0; |
1109 | return 0; |
1110 | } |
1111 | |
1112 | static inline int input_available_p(struct tty_struct *tty, int amt) |
1113 | { |
1114 | if (tty->icanon) { |
1115 | if (tty->canon_data) |
1116 | return 1; |
1117 | } else if (tty->read_cnt >= (amt ? amt : 1)) |
1118 | return 1; |
1119 | |
1120 | return 0; |
1121 | } |
1122 | |
1123 | /** |
1124 | * copy_from_read_buf - copy read data directly |
1125 | * @tty: terminal device |
1126 | * @b: user data |
1127 | * @nr: size of data |
1128 | * |
1129 | * Helper function to speed up read_chan. It is only called when |
1130 | * ICANON is off; it copies characters straight from the tty queue to |
1131 | * user space directly. It can be profitably called twice; once to |
1132 | * drain the space from the tail pointer to the (physical) end of the |
1133 | * buffer, and once to drain the space from the (physical) beginning of |
1134 | * the buffer to head pointer. |
1135 | * |
1136 | * Called under the tty->atomic_read sem and with TTY_DONT_FLIP set |
1137 | * |
1138 | */ |
1139 | |
1140 | static inline int copy_from_read_buf(struct tty_struct *tty, |
1141 | unsigned char __user **b, |
1142 | size_t *nr) |
1143 | |
1144 | { |
1145 | int retval; |
1146 | size_t n; |
1147 | unsigned long flags; |
1148 | |
1149 | retval = 0; |
1150 | spin_lock_irqsave(&tty->read_lock, flags); |
1151 | n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail); |
1152 | n = min(*nr, n); |
1153 | spin_unlock_irqrestore(&tty->read_lock, flags); |
1154 | if (n) { |
1155 | mb(); |
1156 | retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n); |
1157 | n -= retval; |
1158 | spin_lock_irqsave(&tty->read_lock, flags); |
1159 | tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1); |
1160 | tty->read_cnt -= n; |
1161 | spin_unlock_irqrestore(&tty->read_lock, flags); |
1162 | *b += n; |
1163 | *nr -= n; |
1164 | } |
1165 | return retval; |
1166 | } |
1167 | |
1168 | extern ssize_t redirected_tty_write(struct file *,const char *,size_t,loff_t *); |
1169 | |
1170 | /** |
1171 | * job_control - check job control |
1172 | * @tty: tty |
1173 | * @file: file handle |
1174 | * |
1175 | * Perform job control management checks on this file/tty descriptor |
1176 | * and if appropriate send any needed signals and return a negative |
1177 | * error code if action should be taken. |
1178 | */ |
1179 | |
1180 | static int job_control(struct tty_struct *tty, struct file *file) |
1181 | { |
1182 | /* Job control check -- must be done at start and after |
1183 | every sleep (POSIX.1 7.1.1.4). */ |
1184 | /* NOTE: not yet done after every sleep pending a thorough |
1185 | check of the logic of this change. -- jlc */ |
1186 | /* don't stop on /dev/console */ |
1187 | if (file->f_op->write != redirected_tty_write && |
1188 | current->signal->tty == tty) { |
1189 | if (tty->pgrp <= 0) |
1190 | printk("read_chan: tty->pgrp <= 0!\n"); |
1191 | else if (process_group(current) != tty->pgrp) { |
1192 | if (is_ignored(SIGTTIN) || |
1193 | is_orphaned_pgrp(process_group(current))) |
1194 | return -EIO; |
1195 | kill_pg(process_group(current), SIGTTIN, 1); |
1196 | return -ERESTARTSYS; |
1197 | } |
1198 | } |
1199 | return 0; |
1200 | } |
1201 | |
1202 | |
1203 | /** |
1204 | * read_chan - read function for tty |
1205 | * @tty: tty device |
1206 | * @file: file object |
1207 | * @buf: userspace buffer pointer |
1208 | * @nr: size of I/O |
1209 | * |
1210 | * Perform reads for the line discipline. We are guaranteed that the |
1211 | * line discipline will not be closed under us but we may get multiple |
1212 | * parallel readers and must handle this ourselves. We may also get |
1213 | * a hangup. Always called in user context, may sleep. |
1214 | * |
1215 | * This code must be sure never to sleep through a hangup. |
1216 | */ |
1217 | |
1218 | static ssize_t read_chan(struct tty_struct *tty, struct file *file, |
1219 | unsigned char __user *buf, size_t nr) |
1220 | { |
1221 | unsigned char __user *b = buf; |
1222 | DECLARE_WAITQUEUE(wait, current); |
1223 | int c; |
1224 | int minimum, time; |
1225 | ssize_t retval = 0; |
1226 | ssize_t size; |
1227 | long timeout; |
1228 | unsigned long flags; |
1229 | |
1230 | do_it_again: |
1231 | |
1232 | if (!tty->read_buf) { |
1233 | printk("n_tty_read_chan: called with read_buf == NULL?!?\n"); |
1234 | return -EIO; |
1235 | } |
1236 | |
1237 | c = job_control(tty, file); |
1238 | if(c < 0) |
1239 | return c; |
1240 | |
1241 | minimum = time = 0; |
1242 | timeout = MAX_SCHEDULE_TIMEOUT; |
1243 | if (!tty->icanon) { |
1244 | time = (HZ / 10) * TIME_CHAR(tty); |
1245 | minimum = MIN_CHAR(tty); |
1246 | if (minimum) { |
1247 | if (time) |
1248 | tty->minimum_to_wake = 1; |
1249 | else if (!waitqueue_active(&tty->read_wait) || |
1250 | (tty->minimum_to_wake > minimum)) |
1251 | tty->minimum_to_wake = minimum; |
1252 | } else { |
1253 | timeout = 0; |
1254 | if (time) { |
1255 | timeout = time; |
1256 | time = 0; |
1257 | } |
1258 | tty->minimum_to_wake = minimum = 1; |
1259 | } |
1260 | } |
1261 | |
1262 | /* |
1263 | * Internal serialization of reads. |
1264 | */ |
1265 | if (file->f_flags & O_NONBLOCK) { |
1266 | if (down_trylock(&tty->atomic_read)) |
1267 | return -EAGAIN; |
1268 | } |
1269 | else { |
1270 | if (down_interruptible(&tty->atomic_read)) |
1271 | return -ERESTARTSYS; |
1272 | } |
1273 | |
1274 | add_wait_queue(&tty->read_wait, &wait); |
1275 | set_bit(TTY_DONT_FLIP, &tty->flags); |
1276 | while (nr) { |
1277 | /* First test for status change. */ |
1278 | if (tty->packet && tty->link->ctrl_status) { |
1279 | unsigned char cs; |
1280 | if (b != buf) |
1281 | break; |
1282 | cs = tty->link->ctrl_status; |
1283 | tty->link->ctrl_status = 0; |
1284 | if (put_user(cs, b++)) { |
1285 | retval = -EFAULT; |
1286 | b--; |
1287 | break; |
1288 | } |
1289 | nr--; |
1290 | break; |
1291 | } |
1292 | /* This statement must be first before checking for input |
1293 | so that any interrupt will set the state back to |
1294 | TASK_RUNNING. */ |
1295 | set_current_state(TASK_INTERRUPTIBLE); |
1296 | |
1297 | if (((minimum - (b - buf)) < tty->minimum_to_wake) && |
1298 | ((minimum - (b - buf)) >= 1)) |
1299 | tty->minimum_to_wake = (minimum - (b - buf)); |
1300 | |
1301 | if (!input_available_p(tty, 0)) { |
1302 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { |
1303 | retval = -EIO; |
1304 | break; |
1305 | } |
1306 | if (tty_hung_up_p(file)) |
1307 | break; |
1308 | if (!timeout) |
1309 | break; |
1310 | if (file->f_flags & O_NONBLOCK) { |
1311 | retval = -EAGAIN; |
1312 | break; |
1313 | } |
1314 | if (signal_pending(current)) { |
1315 | retval = -ERESTARTSYS; |
1316 | break; |
1317 | } |
1318 | clear_bit(TTY_DONT_FLIP, &tty->flags); |
1319 | timeout = schedule_timeout(timeout); |
1320 | set_bit(TTY_DONT_FLIP, &tty->flags); |
1321 | continue; |
1322 | } |
1323 | __set_current_state(TASK_RUNNING); |
1324 | |
1325 | /* Deal with packet mode. */ |
1326 | if (tty->packet && b == buf) { |
1327 | if (put_user(TIOCPKT_DATA, b++)) { |
1328 | retval = -EFAULT; |
1329 | b--; |
1330 | break; |
1331 | } |
1332 | nr--; |
1333 | } |
1334 | |
1335 | if (tty->icanon) { |
1336 | /* N.B. avoid overrun if nr == 0 */ |
1337 | while (nr && tty->read_cnt) { |
1338 | int eol; |
1339 | |
1340 | eol = test_and_clear_bit(tty->read_tail, |
1341 | tty->read_flags); |
1342 | c = tty->read_buf[tty->read_tail]; |
1343 | spin_lock_irqsave(&tty->read_lock, flags); |
1344 | tty->read_tail = ((tty->read_tail+1) & |
1345 | (N_TTY_BUF_SIZE-1)); |
1346 | tty->read_cnt--; |
1347 | if (eol) { |
1348 | /* this test should be redundant: |
1349 | * we shouldn't be reading data if |
1350 | * canon_data is 0 |
1351 | */ |
1352 | if (--tty->canon_data < 0) |
1353 | tty->canon_data = 0; |
1354 | } |
1355 | spin_unlock_irqrestore(&tty->read_lock, flags); |
1356 | |
1357 | if (!eol || (c != __DISABLED_CHAR)) { |
1358 | if (put_user(c, b++)) { |
1359 | retval = -EFAULT; |
1360 | b--; |
1361 | break; |
1362 | } |
1363 | nr--; |
1364 | } |
1365 | if (eol) |
1366 | break; |
1367 | } |
1368 | if (retval) |
1369 | break; |
1370 | } else { |
1371 | int uncopied; |
1372 | uncopied = copy_from_read_buf(tty, &b, &nr); |
1373 | uncopied += copy_from_read_buf(tty, &b, &nr); |
1374 | if (uncopied) { |
1375 | retval = -EFAULT; |
1376 | break; |
1377 | } |
1378 | } |
1379 | |
1380 | /* If there is enough space in the read buffer now, let the |
1381 | * low-level driver know. We use n_tty_chars_in_buffer() to |
1382 | * check the buffer, as it now knows about canonical mode. |
1383 | * Otherwise, if the driver is throttled and the line is |
1384 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, |
1385 | * we won't get any more characters. |
1386 | */ |
1387 | if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) |
1388 | check_unthrottle(tty); |
1389 | |
1390 | if (b - buf >= minimum) |
1391 | break; |
1392 | if (time) |
1393 | timeout = time; |
1394 | } |
1395 | clear_bit(TTY_DONT_FLIP, &tty->flags); |
1396 | up(&tty->atomic_read); |
1397 | remove_wait_queue(&tty->read_wait, &wait); |
1398 | |
1399 | if (!waitqueue_active(&tty->read_wait)) |
1400 | tty->minimum_to_wake = minimum; |
1401 | |
1402 | __set_current_state(TASK_RUNNING); |
1403 | size = b - buf; |
1404 | if (size) { |
1405 | retval = size; |
1406 | if (nr) |
1407 | clear_bit(TTY_PUSH, &tty->flags); |
1408 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) |
1409 | goto do_it_again; |
1410 | |
1411 | return retval; |
1412 | } |
1413 | |
1414 | /** |
1415 | * write_chan - write function for tty |
1416 | * @tty: tty device |
1417 | * @file: file object |
1418 | * @buf: userspace buffer pointer |
1419 | * @nr: size of I/O |
1420 | * |
1421 | * Write function of the terminal device. This is serialized with |
1422 | * respect to other write callers but not to termios changes, reads |
1423 | * and other such events. We must be careful with N_TTY as the receive |
1424 | * code will echo characters, thus calling driver write methods. |
1425 | * |
1426 | * This code must be sure never to sleep through a hangup. |
1427 | */ |
1428 | |
1429 | static ssize_t write_chan(struct tty_struct * tty, struct file * file, |
1430 | const unsigned char * buf, size_t nr) |
1431 | { |
1432 | const unsigned char *b = buf; |
1433 | DECLARE_WAITQUEUE(wait, current); |
1434 | int c; |
1435 | ssize_t retval = 0; |
1436 | |
1437 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ |
1438 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { |
1439 | retval = tty_check_change(tty); |
1440 | if (retval) |
1441 | return retval; |
1442 | } |
1443 | |
1444 | add_wait_queue(&tty->write_wait, &wait); |
1445 | while (1) { |
1446 | set_current_state(TASK_INTERRUPTIBLE); |
1447 | if (signal_pending(current)) { |
1448 | retval = -ERESTARTSYS; |
1449 | break; |
1450 | } |
1451 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { |
1452 | retval = -EIO; |
1453 | break; |
1454 | } |
1455 | if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { |
1456 | while (nr > 0) { |
1457 | ssize_t num = opost_block(tty, b, nr); |
1458 | if (num < 0) { |
1459 | if (num == -EAGAIN) |
1460 | break; |
1461 | retval = num; |
1462 | goto break_out; |
1463 | } |
1464 | b += num; |
1465 | nr -= num; |
1466 | if (nr == 0) |
1467 | break; |
1468 | c = *b; |
1469 | if (opost(c, tty) < 0) |
1470 | break; |
1471 | b++; nr--; |
1472 | } |
1473 | if (tty->driver->flush_chars) |
1474 | tty->driver->flush_chars(tty); |
1475 | } else { |
1476 | c = tty->driver->write(tty, b, nr); |
1477 | if (c < 0) { |
1478 | retval = c; |
1479 | goto break_out; |
1480 | } |
1481 | b += c; |
1482 | nr -= c; |
1483 | } |
1484 | if (!nr) |
1485 | break; |
1486 | if (file->f_flags & O_NONBLOCK) { |
1487 | retval = -EAGAIN; |
1488 | break; |
1489 | } |
1490 | schedule(); |
1491 | } |
1492 | break_out: |
1493 | __set_current_state(TASK_RUNNING); |
1494 | remove_wait_queue(&tty->write_wait, &wait); |
1495 | return (b - buf) ? b - buf : retval; |
1496 | } |
1497 | |
1498 | /** |
1499 | * normal_poll - poll method for N_TTY |
1500 | * @tty: terminal device |
1501 | * @file: file accessing it |
1502 | * @wait: poll table |
1503 | * |
1504 | * Called when the line discipline is asked to poll() for data or |
1505 | * for special events. This code is not serialized with respect to |
1506 | * other events save open/close. |
1507 | * |
1508 | * This code must be sure never to sleep through a hangup. |
1509 | * Called without the kernel lock held - fine |
1510 | * |
1511 | * FIXME: if someone changes the VMIN or discipline settings for the |
1512 | * terminal while another process is in poll() the poll does not |
1513 | * recompute the new limits. Possibly set_termios should issue |
1514 | * a read wakeup to fix this bug. |
1515 | */ |
1516 | |
1517 | static unsigned int normal_poll(struct tty_struct * tty, struct file * file, poll_table *wait) |
1518 | { |
1519 | unsigned int mask = 0; |
1520 | |
1521 | poll_wait(file, &tty->read_wait, wait); |
1522 | poll_wait(file, &tty->write_wait, wait); |
1523 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) |
1524 | mask |= POLLIN | POLLRDNORM; |
1525 | if (tty->packet && tty->link->ctrl_status) |
1526 | mask |= POLLPRI | POLLIN | POLLRDNORM; |
1527 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) |
1528 | mask |= POLLHUP; |
1529 | if (tty_hung_up_p(file)) |
1530 | mask |= POLLHUP; |
1531 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { |
1532 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) |
1533 | tty->minimum_to_wake = MIN_CHAR(tty); |
1534 | else |
1535 | tty->minimum_to_wake = 1; |
1536 | } |
1537 | if (tty->driver->chars_in_buffer(tty) < WAKEUP_CHARS && |
1538 | tty->driver->write_room(tty) > 0) |
1539 | mask |= POLLOUT | POLLWRNORM; |
1540 | return mask; |
1541 | } |
1542 | |
1543 | struct tty_ldisc tty_ldisc_N_TTY = { |
1544 | TTY_LDISC_MAGIC, /* magic */ |
1545 | "n_tty", /* name */ |
1546 | 0, /* num */ |
1547 | 0, /* flags */ |
1548 | n_tty_open, /* open */ |
1549 | n_tty_close, /* close */ |
1550 | n_tty_flush_buffer, /* flush_buffer */ |
1551 | n_tty_chars_in_buffer, /* chars_in_buffer */ |
1552 | read_chan, /* read */ |
1553 | write_chan, /* write */ |
1554 | n_tty_ioctl, /* ioctl */ |
1555 | n_tty_set_termios, /* set_termios */ |
1556 | normal_poll, /* poll */ |
1557 | NULL, /* hangup */ |
1558 | n_tty_receive_buf, /* receive_buf */ |
1559 | n_tty_receive_room, /* receive_room */ |
1560 | n_tty_write_wakeup /* write_wakeup */ |
1561 | }; |
1562 |