blob: 39d6ab6551e0884db2237f6ffeba184de92f4c22 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * n_tty.c --- implements the N_TTY line discipline.
Alan Cox4edf1822008-02-08 04:18:44 -08003 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * 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
Alan Cox4edf1822008-02-08 04:18:44 -080011 * to N_TTY if it can not switch to any other line discipline.
Linus Torvalds1da177e2005-04-16 15:20:36 -070012 *
13 * Written by Theodore Ts'o, Copyright 1994.
Alan Cox4edf1822008-02-08 04:18:44 -080014 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070015 * This file also contains code originally written by Linus Torvalds,
16 * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994.
Alan Cox4edf1822008-02-08 04:18:44 -080017 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070018 * 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 *
Alan Cox4edf1822008-02-08 04:18:44 -080023 * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of
Linus Torvalds1da177e2005-04-16 15:20:36 -070024 * 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>.
Alan Cox11a96d12008-10-13 10:46:24 +010029 * Also fixed a bug in BLOCKING mode where n_tty_write returns
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 * 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>
Miloslav Trmac522ed772007-07-15 23:40:56 -070048#include <linux/audit.h>
49#include <linux/file.h>
Alan Cox300a6202009-01-02 13:41:04 +000050#include <linux/uaccess.h>
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -080051#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
Linus Torvalds1da177e2005-04-16 15:20:36 -070053#include <asm/system.h>
54
55/* number of characters left in xmit buffer before select has we have room */
56#define WAKEUP_CHARS 256
57
58/*
59 * This defines the low- and high-watermarks for throttling and
60 * unthrottling the TTY driver. These watermarks are used for
61 * controlling the space in the read buffer.
62 */
63#define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */
64#define TTY_THRESHOLD_UNTHROTTLE 128
65
Joe Petersona88a69c2009-01-02 13:40:53 +000066/*
67 * Special byte codes used in the echo buffer to represent operations
68 * or special handling of characters. Bytes in the echo buffer that
69 * are not part of such special blocks are treated as normal character
70 * codes.
71 */
72#define ECHO_OP_START 0xff
73#define ECHO_OP_MOVE_BACK_COL 0x80
74#define ECHO_OP_SET_CANON_COL 0x81
75#define ECHO_OP_ERASE_TAB 0x82
76
Miloslav Trmac522ed772007-07-15 23:40:56 -070077static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
78 unsigned char __user *ptr)
79{
80 tty_audit_add_data(tty, &x, 1);
81 return put_user(x, ptr);
82}
83
Linus Torvalds55db4c62011-06-04 06:33:24 +090084/**
85 * n_tty_set__room - receive space
86 * @tty: terminal
87 *
88 * Called by the driver to find out how much data it is
89 * permitted to feed to the line discipline without any being lost
90 * and thus to manage flow control. Not serialized. Answers for the
91 * "instant".
92 */
93
94static void n_tty_set_room(struct tty_struct *tty)
95{
96 /* tty->read_cnt is not read locked ? */
97 int left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
98 int old_left;
99
100 /*
101 * If we are doing input canonicalization, and there are no
102 * pending newlines, let characters through without limit, so
103 * that erase characters will be handled. Other excess
104 * characters will be beeped.
105 */
106 if (left <= 0)
107 left = tty->icanon && !tty->canon_data;
108 old_left = tty->receive_room;
109 tty->receive_room = left;
110
111 /* Did this open up the receive buffer? We may need to flip */
112 if (left && !old_left)
113 schedule_work(&tty->buf.work);
114}
115
Alan Cox33f0f882006-01-09 20:54:13 -0800116static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117{
118 if (tty->read_cnt < N_TTY_BUF_SIZE) {
119 tty->read_buf[tty->read_head] = c;
120 tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1);
121 tty->read_cnt++;
122 }
123}
124
Alan Cox17b82062008-10-13 10:45:06 +0100125/**
126 * put_tty_queue - add character to tty
127 * @c: character
128 * @tty: tty device
129 *
130 * Add a character to the tty read_buf queue. This is done under the
131 * read_lock to serialize character addition and also to protect us
132 * against parallel reads or flushes
133 */
134
Alan Cox33f0f882006-01-09 20:54:13 -0800135static void put_tty_queue(unsigned char c, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136{
137 unsigned long flags;
138 /*
139 * The problem of stomping on the buffers ends here.
140 * Why didn't anyone see this one coming? --AJK
141 */
142 spin_lock_irqsave(&tty->read_lock, flags);
143 put_tty_queue_nolock(c, tty);
144 spin_unlock_irqrestore(&tty->read_lock, flags);
145}
146
147/**
148 * check_unthrottle - allow new receive data
149 * @tty; tty device
150 *
Alan Cox17b82062008-10-13 10:45:06 +0100151 * Check whether to call the driver unthrottle functions
152 *
Ingo Molnar70522e12006-03-23 03:00:31 -0800153 * Can sleep, may be called under the atomic_read_lock mutex but
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 * this is not guaranteed.
155 */
Alan Cox4edf1822008-02-08 04:18:44 -0800156static void check_unthrottle(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157{
Alan Cox39c2e602008-04-30 00:54:18 -0700158 if (tty->count)
159 tty_unthrottle(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160}
161
162/**
163 * reset_buffer_flags - reset buffer state
164 * @tty: terminal to reset
165 *
Alan Cox4edf1822008-02-08 04:18:44 -0800166 * Reset the read buffer counters, clear the flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 * and make sure the driver is unthrottled. Called
168 * from n_tty_open() and n_tty_flush_buffer().
Alan Cox17b82062008-10-13 10:45:06 +0100169 *
170 * Locking: tty_read_lock for read fields.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000172
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173static void reset_buffer_flags(struct tty_struct *tty)
174{
175 unsigned long flags;
176
177 spin_lock_irqsave(&tty->read_lock, flags);
178 tty->read_head = tty->read_tail = tty->read_cnt = 0;
179 spin_unlock_irqrestore(&tty->read_lock, flags);
Joe Petersona88a69c2009-01-02 13:40:53 +0000180
181 mutex_lock(&tty->echo_lock);
182 tty->echo_pos = tty->echo_cnt = tty->echo_overrun = 0;
183 mutex_unlock(&tty->echo_lock);
184
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 tty->canon_head = tty->canon_data = tty->erasing = 0;
186 memset(&tty->read_flags, 0, sizeof tty->read_flags);
Linus Torvalds55db4c62011-06-04 06:33:24 +0900187 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188}
189
190/**
191 * n_tty_flush_buffer - clean input queue
192 * @tty: terminal device
193 *
194 * Flush the input buffer. Called when the line discipline is
195 * being closed, when the tty layer wants the buffer flushed (eg
196 * at hangup) or when the N_TTY line discipline internally has to
197 * clean the pending queue (for example some signals).
198 *
Alan Cox17b82062008-10-13 10:45:06 +0100199 * Locking: ctrl_lock, read_lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 */
Alan Cox4edf1822008-02-08 04:18:44 -0800201
202static void n_tty_flush_buffer(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203{
Alan Cox04f378b2008-04-30 00:53:29 -0700204 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 /* clear everything and unthrottle the driver */
206 reset_buffer_flags(tty);
Alan Cox4edf1822008-02-08 04:18:44 -0800207
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 if (!tty->link)
209 return;
210
Alan Cox04f378b2008-04-30 00:53:29 -0700211 spin_lock_irqsave(&tty->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 if (tty->link->packet) {
213 tty->ctrl_status |= TIOCPKT_FLUSHREAD;
214 wake_up_interruptible(&tty->link->read_wait);
215 }
Alan Cox04f378b2008-04-30 00:53:29 -0700216 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217}
218
219/**
220 * n_tty_chars_in_buffer - report available bytes
221 * @tty: tty device
222 *
223 * Report the number of characters buffered to be delivered to user
Alan Cox4edf1822008-02-08 04:18:44 -0800224 * at this instant in time.
Alan Cox17b82062008-10-13 10:45:06 +0100225 *
226 * Locking: read_lock
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 */
Alan Cox4edf1822008-02-08 04:18:44 -0800228
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
230{
231 unsigned long flags;
232 ssize_t n = 0;
233
234 spin_lock_irqsave(&tty->read_lock, flags);
235 if (!tty->icanon) {
236 n = tty->read_cnt;
237 } else if (tty->canon_data) {
238 n = (tty->canon_head > tty->read_tail) ?
239 tty->canon_head - tty->read_tail :
240 tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail);
241 }
242 spin_unlock_irqrestore(&tty->read_lock, flags);
243 return n;
244}
245
246/**
247 * is_utf8_continuation - utf8 multibyte check
248 * @c: byte to check
249 *
250 * Returns true if the utf8 character 'c' is a multibyte continuation
251 * character. We use this to correctly compute the on screen size
252 * of the character when printing
253 */
Alan Cox4edf1822008-02-08 04:18:44 -0800254
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255static inline int is_utf8_continuation(unsigned char c)
256{
257 return (c & 0xc0) == 0x80;
258}
259
260/**
261 * is_continuation - multibyte check
262 * @c: byte to check
263 *
264 * Returns true if the utf8 character 'c' is a multibyte continuation
265 * character and the terminal is in unicode mode.
266 */
Alan Cox4edf1822008-02-08 04:18:44 -0800267
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268static inline int is_continuation(unsigned char c, struct tty_struct *tty)
269{
270 return I_IUTF8(tty) && is_utf8_continuation(c);
271}
272
273/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000274 * do_output_char - output one character
275 * @c: character (or partial unicode symbol)
276 * @tty: terminal device
277 * @space: space available in tty driver write buffer
278 *
279 * This is a helper function that handles one output character
280 * (including special characters like TAB, CR, LF, etc.),
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600281 * doing OPOST processing and putting the results in the
282 * tty driver's write buffer.
Joe Petersona88a69c2009-01-02 13:40:53 +0000283 *
284 * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY
285 * and NLDLY. They simply aren't relevant in the world today.
286 * If you ever need them, add them here.
287 *
288 * Returns the number of bytes of buffer space used or -1 if
289 * no space left.
290 *
291 * Locking: should be called under the output_lock to protect
292 * the column state and space left in the buffer
293 */
294
295static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
296{
297 int spaces;
298
299 if (!space)
300 return -1;
Alan Cox300a6202009-01-02 13:41:04 +0000301
Joe Petersona88a69c2009-01-02 13:40:53 +0000302 switch (c) {
303 case '\n':
304 if (O_ONLRET(tty))
305 tty->column = 0;
306 if (O_ONLCR(tty)) {
307 if (space < 2)
308 return -1;
309 tty->canon_column = tty->column = 0;
Linus Torvalds37f81fa2009-09-05 12:46:07 -0700310 tty->ops->write(tty, "\r\n", 2);
Joe Petersona88a69c2009-01-02 13:40:53 +0000311 return 2;
312 }
313 tty->canon_column = tty->column;
314 break;
315 case '\r':
316 if (O_ONOCR(tty) && tty->column == 0)
317 return 0;
318 if (O_OCRNL(tty)) {
319 c = '\n';
320 if (O_ONLRET(tty))
321 tty->canon_column = tty->column = 0;
322 break;
323 }
324 tty->canon_column = tty->column = 0;
325 break;
326 case '\t':
327 spaces = 8 - (tty->column & 7);
328 if (O_TABDLY(tty) == XTABS) {
329 if (space < spaces)
330 return -1;
331 tty->column += spaces;
332 tty->ops->write(tty, " ", spaces);
333 return spaces;
334 }
335 tty->column += spaces;
336 break;
337 case '\b':
338 if (tty->column > 0)
339 tty->column--;
340 break;
341 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000342 if (!iscntrl(c)) {
343 if (O_OLCUC(tty))
344 c = toupper(c);
345 if (!is_continuation(c, tty))
346 tty->column++;
347 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000348 break;
349 }
350
351 tty_put_char(tty, c);
352 return 1;
353}
354
355/**
356 * process_output - output post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 * @c: character (or partial unicode symbol)
358 * @tty: terminal device
359 *
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600360 * Output one character with OPOST processing.
361 * Returns -1 when the output device is full and the character
362 * must be retried.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000364 * Locking: output_lock to protect column state and space left
365 * (also, this is called from n_tty_write under the
366 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 */
Alan Cox4edf1822008-02-08 04:18:44 -0800368
Joe Petersona88a69c2009-01-02 13:40:53 +0000369static int process_output(unsigned char c, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370{
Joe Petersona88a69c2009-01-02 13:40:53 +0000371 int space, retval;
372
373 mutex_lock(&tty->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374
Alan Coxf34d7a52008-04-30 00:54:13 -0700375 space = tty_write_room(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +0000376 retval = do_output_char(c, tty, space);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377
Joe Petersona88a69c2009-01-02 13:40:53 +0000378 mutex_unlock(&tty->output_lock);
379 if (retval < 0)
380 return -1;
381 else
382 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383}
384
385/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000386 * process_output_block - block post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 * @tty: terminal device
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600388 * @buf: character buffer
389 * @nr: number of bytes to output
390 *
391 * Output a block of characters with OPOST processing.
392 * Returns the number of characters output.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 *
394 * This path is used to speed up block console writes, among other
395 * things when processing blocks of output data. It handles only
396 * the simple cases normally found and helps to generate blocks of
397 * symbols for the console driver and thus improve performance.
398 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000399 * Locking: output_lock to protect column state and space left
400 * (also, this is called from n_tty_write under the
401 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 */
Alan Cox4edf1822008-02-08 04:18:44 -0800403
Joe Petersona88a69c2009-01-02 13:40:53 +0000404static ssize_t process_output_block(struct tty_struct *tty,
405 const unsigned char *buf, unsigned int nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406{
407 int space;
408 int i;
409 const unsigned char *cp;
410
Joe Petersona88a69c2009-01-02 13:40:53 +0000411 mutex_lock(&tty->output_lock);
412
Alan Coxf34d7a52008-04-30 00:54:13 -0700413 space = tty_write_room(tty);
Alan Cox300a6202009-01-02 13:41:04 +0000414 if (!space) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000415 mutex_unlock(&tty->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 return 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000417 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 if (nr > space)
419 nr = space;
420
421 for (i = 0, cp = buf; i < nr; i++, cp++) {
Joe Petersona59c0d62009-01-02 13:43:25 +0000422 unsigned char c = *cp;
423
424 switch (c) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 case '\n':
426 if (O_ONLRET(tty))
427 tty->column = 0;
428 if (O_ONLCR(tty))
429 goto break_out;
430 tty->canon_column = tty->column;
431 break;
432 case '\r':
433 if (O_ONOCR(tty) && tty->column == 0)
434 goto break_out;
435 if (O_OCRNL(tty))
436 goto break_out;
437 tty->canon_column = tty->column = 0;
438 break;
439 case '\t':
440 goto break_out;
441 case '\b':
442 if (tty->column > 0)
443 tty->column--;
444 break;
445 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000446 if (!iscntrl(c)) {
447 if (O_OLCUC(tty))
448 goto break_out;
449 if (!is_continuation(c, tty))
450 tty->column++;
451 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452 break;
453 }
454 }
455break_out:
Alan Coxf34d7a52008-04-30 00:54:13 -0700456 i = tty->ops->write(tty, buf, i);
Joe Petersona88a69c2009-01-02 13:40:53 +0000457
458 mutex_unlock(&tty->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 return i;
460}
461
Joe Petersona88a69c2009-01-02 13:40:53 +0000462/**
463 * process_echoes - write pending echo characters
464 * @tty: terminal device
465 *
466 * Write previously buffered echo (and other ldisc-generated)
467 * characters to the tty.
468 *
469 * Characters generated by the ldisc (including echoes) need to
470 * be buffered because the driver's write buffer can fill during
471 * heavy program output. Echoing straight to the driver will
472 * often fail under these conditions, causing lost characters and
473 * resulting mismatches of ldisc state information.
474 *
475 * Since the ldisc state must represent the characters actually sent
476 * to the driver at the time of the write, operations like certain
477 * changes in column state are also saved in the buffer and executed
478 * here.
479 *
480 * A circular fifo buffer is used so that the most recent characters
481 * are prioritized. Also, when control characters are echoed with a
482 * prefixed "^", the pair is treated atomically and thus not separated.
483 *
484 * Locking: output_lock to protect column state and space left,
485 * echo_lock to protect the echo buffer
486 */
487
488static void process_echoes(struct tty_struct *tty)
489{
490 int space, nr;
491 unsigned char c;
492 unsigned char *cp, *buf_end;
493
494 if (!tty->echo_cnt)
495 return;
496
497 mutex_lock(&tty->output_lock);
498 mutex_lock(&tty->echo_lock);
499
500 space = tty_write_room(tty);
501
502 buf_end = tty->echo_buf + N_TTY_BUF_SIZE;
503 cp = tty->echo_buf + tty->echo_pos;
504 nr = tty->echo_cnt;
505 while (nr > 0) {
506 c = *cp;
507 if (c == ECHO_OP_START) {
508 unsigned char op;
509 unsigned char *opp;
510 int no_space_left = 0;
511
512 /*
513 * If the buffer byte is the start of a multi-byte
514 * operation, get the next byte, which is either the
515 * op code or a control character value.
516 */
517 opp = cp + 1;
518 if (opp == buf_end)
519 opp -= N_TTY_BUF_SIZE;
520 op = *opp;
Alan Cox300a6202009-01-02 13:41:04 +0000521
Joe Petersona88a69c2009-01-02 13:40:53 +0000522 switch (op) {
523 unsigned int num_chars, num_bs;
524
525 case ECHO_OP_ERASE_TAB:
526 if (++opp == buf_end)
527 opp -= N_TTY_BUF_SIZE;
528 num_chars = *opp;
529
530 /*
531 * Determine how many columns to go back
532 * in order to erase the tab.
533 * This depends on the number of columns
534 * used by other characters within the tab
535 * area. If this (modulo 8) count is from
536 * the start of input rather than from a
537 * previous tab, we offset by canon column.
538 * Otherwise, tab spacing is normal.
539 */
540 if (!(num_chars & 0x80))
541 num_chars += tty->canon_column;
542 num_bs = 8 - (num_chars & 7);
543
544 if (num_bs > space) {
545 no_space_left = 1;
546 break;
547 }
548 space -= num_bs;
549 while (num_bs--) {
550 tty_put_char(tty, '\b');
551 if (tty->column > 0)
552 tty->column--;
553 }
554 cp += 3;
555 nr -= 3;
556 break;
557
558 case ECHO_OP_SET_CANON_COL:
559 tty->canon_column = tty->column;
560 cp += 2;
561 nr -= 2;
562 break;
563
564 case ECHO_OP_MOVE_BACK_COL:
565 if (tty->column > 0)
566 tty->column--;
567 cp += 2;
568 nr -= 2;
569 break;
570
571 case ECHO_OP_START:
572 /* This is an escaped echo op start code */
573 if (!space) {
574 no_space_left = 1;
575 break;
576 }
577 tty_put_char(tty, ECHO_OP_START);
578 tty->column++;
579 space--;
580 cp += 2;
581 nr -= 2;
582 break;
583
584 default:
Joe Petersona88a69c2009-01-02 13:40:53 +0000585 /*
Joe Peterson62b26352009-09-09 15:03:47 -0600586 * If the op is not a special byte code,
587 * it is a ctrl char tagged to be echoed
588 * as "^X" (where X is the letter
589 * representing the control char).
590 * Note that we must ensure there is
591 * enough space for the whole ctrl pair.
592 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000593 */
Joe Peterson62b26352009-09-09 15:03:47 -0600594 if (space < 2) {
595 no_space_left = 1;
596 break;
597 }
598 tty_put_char(tty, '^');
599 tty_put_char(tty, op ^ 0100);
600 tty->column += 2;
601 space -= 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000602 cp += 2;
603 nr -= 2;
604 }
605
606 if (no_space_left)
607 break;
608 } else {
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600609 if (O_OPOST(tty) &&
610 !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
611 int retval = do_output_char(c, tty, space);
612 if (retval < 0)
613 break;
614 space -= retval;
615 } else {
616 if (!space)
617 break;
618 tty_put_char(tty, c);
619 space -= 1;
620 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000621 cp += 1;
622 nr -= 1;
623 }
624
625 /* When end of circular buffer reached, wrap around */
626 if (cp >= buf_end)
627 cp -= N_TTY_BUF_SIZE;
628 }
629
630 if (nr == 0) {
631 tty->echo_pos = 0;
632 tty->echo_cnt = 0;
633 tty->echo_overrun = 0;
634 } else {
635 int num_processed = tty->echo_cnt - nr;
636 tty->echo_pos += num_processed;
637 tty->echo_pos &= N_TTY_BUF_SIZE - 1;
638 tty->echo_cnt = nr;
639 if (num_processed > 0)
640 tty->echo_overrun = 0;
641 }
642
643 mutex_unlock(&tty->echo_lock);
644 mutex_unlock(&tty->output_lock);
645
646 if (tty->ops->flush_chars)
647 tty->ops->flush_chars(tty);
648}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649
650/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000651 * add_echo_byte - add a byte to the echo buffer
652 * @c: unicode byte to echo
653 * @tty: terminal device
654 *
655 * Add a character or operation byte to the echo buffer.
656 *
657 * Should be called under the echo lock to protect the echo buffer.
658 */
659
660static void add_echo_byte(unsigned char c, struct tty_struct *tty)
661{
662 int new_byte_pos;
663
664 if (tty->echo_cnt == N_TTY_BUF_SIZE) {
665 /* Circular buffer is already at capacity */
666 new_byte_pos = tty->echo_pos;
667
668 /*
669 * Since the buffer start position needs to be advanced,
670 * be sure to step by a whole operation byte group.
671 */
Alan Cox300a6202009-01-02 13:41:04 +0000672 if (tty->echo_buf[tty->echo_pos] == ECHO_OP_START) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000673 if (tty->echo_buf[(tty->echo_pos + 1) &
674 (N_TTY_BUF_SIZE - 1)] ==
675 ECHO_OP_ERASE_TAB) {
676 tty->echo_pos += 3;
677 tty->echo_cnt -= 2;
678 } else {
679 tty->echo_pos += 2;
680 tty->echo_cnt -= 1;
681 }
682 } else {
683 tty->echo_pos++;
684 }
685 tty->echo_pos &= N_TTY_BUF_SIZE - 1;
686
687 tty->echo_overrun = 1;
688 } else {
689 new_byte_pos = tty->echo_pos + tty->echo_cnt;
690 new_byte_pos &= N_TTY_BUF_SIZE - 1;
691 tty->echo_cnt++;
692 }
693
694 tty->echo_buf[new_byte_pos] = c;
695}
696
697/**
698 * echo_move_back_col - add operation to move back a column
699 * @tty: terminal device
700 *
701 * Add an operation to the echo buffer to move back one column.
702 *
703 * Locking: echo_lock to protect the echo buffer
704 */
705
706static void echo_move_back_col(struct tty_struct *tty)
707{
708 mutex_lock(&tty->echo_lock);
709
710 add_echo_byte(ECHO_OP_START, tty);
711 add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty);
712
713 mutex_unlock(&tty->echo_lock);
714}
715
716/**
717 * echo_set_canon_col - add operation to set the canon column
718 * @tty: terminal device
719 *
720 * Add an operation to the echo buffer to set the canon column
721 * to the current column.
722 *
723 * Locking: echo_lock to protect the echo buffer
724 */
725
726static void echo_set_canon_col(struct tty_struct *tty)
727{
728 mutex_lock(&tty->echo_lock);
729
730 add_echo_byte(ECHO_OP_START, tty);
731 add_echo_byte(ECHO_OP_SET_CANON_COL, tty);
732
733 mutex_unlock(&tty->echo_lock);
734}
735
736/**
737 * echo_erase_tab - add operation to erase a tab
738 * @num_chars: number of character columns already used
739 * @after_tab: true if num_chars starts after a previous tab
740 * @tty: terminal device
741 *
742 * Add an operation to the echo buffer to erase a tab.
743 *
744 * Called by the eraser function, which knows how many character
745 * columns have been used since either a previous tab or the start
746 * of input. This information will be used later, along with
747 * canon column (if applicable), to go back the correct number
748 * of columns.
749 *
750 * Locking: echo_lock to protect the echo buffer
751 */
752
753static void echo_erase_tab(unsigned int num_chars, int after_tab,
754 struct tty_struct *tty)
755{
756 mutex_lock(&tty->echo_lock);
757
758 add_echo_byte(ECHO_OP_START, tty);
759 add_echo_byte(ECHO_OP_ERASE_TAB, tty);
760
761 /* We only need to know this modulo 8 (tab spacing) */
762 num_chars &= 7;
763
764 /* Set the high bit as a flag if num_chars is after a previous tab */
765 if (after_tab)
766 num_chars |= 0x80;
Alan Cox300a6202009-01-02 13:41:04 +0000767
Joe Petersona88a69c2009-01-02 13:40:53 +0000768 add_echo_byte(num_chars, tty);
769
770 mutex_unlock(&tty->echo_lock);
771}
772
773/**
774 * echo_char_raw - echo a character raw
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 * @c: unicode byte to echo
776 * @tty: terminal device
777 *
Alan Cox4edf1822008-02-08 04:18:44 -0800778 * Echo user input back onto the screen. This must be called only when
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 * L_ECHO(tty) is true. Called from the driver receive_buf path.
Alan Cox17b82062008-10-13 10:45:06 +0100780 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000781 * This variant does not treat control characters specially.
782 *
783 * Locking: echo_lock to protect the echo buffer
784 */
785
786static void echo_char_raw(unsigned char c, struct tty_struct *tty)
787{
788 mutex_lock(&tty->echo_lock);
789
790 if (c == ECHO_OP_START) {
791 add_echo_byte(ECHO_OP_START, tty);
792 add_echo_byte(ECHO_OP_START, tty);
793 } else {
794 add_echo_byte(c, tty);
795 }
796
797 mutex_unlock(&tty->echo_lock);
798}
799
800/**
801 * echo_char - echo a character
802 * @c: unicode byte to echo
803 * @tty: terminal device
804 *
805 * Echo user input back onto the screen. This must be called only when
806 * L_ECHO(tty) is true. Called from the driver receive_buf path.
807 *
Joe Peterson62b26352009-09-09 15:03:47 -0600808 * This variant tags control characters to be echoed as "^X"
809 * (where X is the letter representing the control char).
Joe Petersona88a69c2009-01-02 13:40:53 +0000810 *
811 * Locking: echo_lock to protect the echo buffer
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812 */
813
814static void echo_char(unsigned char c, struct tty_struct *tty)
815{
Joe Petersona88a69c2009-01-02 13:40:53 +0000816 mutex_lock(&tty->echo_lock);
817
818 if (c == ECHO_OP_START) {
819 add_echo_byte(ECHO_OP_START, tty);
820 add_echo_byte(ECHO_OP_START, tty);
821 } else {
Joe Peterson62b26352009-09-09 15:03:47 -0600822 if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t')
Joe Petersona88a69c2009-01-02 13:40:53 +0000823 add_echo_byte(ECHO_OP_START, tty);
824 add_echo_byte(c, tty);
825 }
826
827 mutex_unlock(&tty->echo_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828}
829
Alan Cox17b82062008-10-13 10:45:06 +0100830/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000831 * finish_erasing - complete erase
Alan Cox17b82062008-10-13 10:45:06 +0100832 * @tty: tty doing the erase
Alan Cox17b82062008-10-13 10:45:06 +0100833 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000834
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835static inline void finish_erasing(struct tty_struct *tty)
836{
837 if (tty->erasing) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000838 echo_char_raw('/', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 tty->erasing = 0;
840 }
841}
842
843/**
844 * eraser - handle erase function
845 * @c: character input
846 * @tty: terminal device
847 *
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200848 * Perform erase and necessary output when an erase character is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 * present in the stream from the driver layer. Handles the complexities
850 * of UTF-8 multibyte symbols.
Alan Cox17b82062008-10-13 10:45:06 +0100851 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000852 * Locking: read_lock for tty buffers
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853 */
Alan Cox4edf1822008-02-08 04:18:44 -0800854
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855static void eraser(unsigned char c, struct tty_struct *tty)
856{
857 enum { ERASE, WERASE, KILL } kill_type;
858 int head, seen_alnums, cnt;
859 unsigned long flags;
860
Alan Cox17b82062008-10-13 10:45:06 +0100861 /* FIXME: locking needed ? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 if (tty->read_head == tty->canon_head) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +0000863 /* process_output('\a', tty); */ /* what do you think? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 return;
865 }
866 if (c == ERASE_CHAR(tty))
867 kill_type = ERASE;
868 else if (c == WERASE_CHAR(tty))
869 kill_type = WERASE;
870 else {
871 if (!L_ECHO(tty)) {
872 spin_lock_irqsave(&tty->read_lock, flags);
873 tty->read_cnt -= ((tty->read_head - tty->canon_head) &
874 (N_TTY_BUF_SIZE - 1));
875 tty->read_head = tty->canon_head;
876 spin_unlock_irqrestore(&tty->read_lock, flags);
877 return;
878 }
879 if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
880 spin_lock_irqsave(&tty->read_lock, flags);
881 tty->read_cnt -= ((tty->read_head - tty->canon_head) &
882 (N_TTY_BUF_SIZE - 1));
883 tty->read_head = tty->canon_head;
884 spin_unlock_irqrestore(&tty->read_lock, flags);
885 finish_erasing(tty);
886 echo_char(KILL_CHAR(tty), tty);
887 /* Add a newline if ECHOK is on and ECHOKE is off. */
888 if (L_ECHOK(tty))
Joe Petersona88a69c2009-01-02 13:40:53 +0000889 echo_char_raw('\n', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890 return;
891 }
892 kill_type = KILL;
893 }
894
895 seen_alnums = 0;
Alan Cox17b82062008-10-13 10:45:06 +0100896 /* FIXME: Locking ?? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 while (tty->read_head != tty->canon_head) {
898 head = tty->read_head;
899
900 /* erase a single possibly multibyte character */
901 do {
902 head = (head - 1) & (N_TTY_BUF_SIZE-1);
903 c = tty->read_buf[head];
904 } while (is_continuation(c, tty) && head != tty->canon_head);
905
906 /* do not partially erase */
907 if (is_continuation(c, tty))
908 break;
909
910 if (kill_type == WERASE) {
911 /* Equivalent to BSD's ALTWERASE. */
912 if (isalnum(c) || c == '_')
913 seen_alnums++;
914 else if (seen_alnums)
915 break;
916 }
917 cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1);
918 spin_lock_irqsave(&tty->read_lock, flags);
919 tty->read_head = head;
920 tty->read_cnt -= cnt;
921 spin_unlock_irqrestore(&tty->read_lock, flags);
922 if (L_ECHO(tty)) {
923 if (L_ECHOPRT(tty)) {
924 if (!tty->erasing) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000925 echo_char_raw('\\', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 tty->erasing = 1;
927 }
928 /* if cnt > 1, output a multi-byte character */
929 echo_char(c, tty);
930 while (--cnt > 0) {
931 head = (head+1) & (N_TTY_BUF_SIZE-1);
Joe Petersona88a69c2009-01-02 13:40:53 +0000932 echo_char_raw(tty->read_buf[head], tty);
933 echo_move_back_col(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934 }
935 } else if (kill_type == ERASE && !L_ECHOE(tty)) {
936 echo_char(ERASE_CHAR(tty), tty);
937 } else if (c == '\t') {
Joe Petersona88a69c2009-01-02 13:40:53 +0000938 unsigned int num_chars = 0;
939 int after_tab = 0;
940 unsigned long tail = tty->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941
Joe Petersona88a69c2009-01-02 13:40:53 +0000942 /*
943 * Count the columns used for characters
944 * since the start of input or after a
945 * previous tab.
946 * This info is used to go back the correct
947 * number of columns.
948 */
949 while (tail != tty->canon_head) {
950 tail = (tail-1) & (N_TTY_BUF_SIZE-1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 c = tty->read_buf[tail];
Joe Petersona88a69c2009-01-02 13:40:53 +0000952 if (c == '\t') {
953 after_tab = 1;
954 break;
Alan Cox300a6202009-01-02 13:41:04 +0000955 } else if (iscntrl(c)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956 if (L_ECHOCTL(tty))
Joe Petersona88a69c2009-01-02 13:40:53 +0000957 num_chars += 2;
958 } else if (!is_continuation(c, tty)) {
959 num_chars++;
960 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000962 echo_erase_tab(num_chars, after_tab, tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963 } else {
964 if (iscntrl(c) && L_ECHOCTL(tty)) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000965 echo_char_raw('\b', tty);
966 echo_char_raw(' ', tty);
967 echo_char_raw('\b', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 }
969 if (!iscntrl(c) || L_ECHOCTL(tty)) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000970 echo_char_raw('\b', tty);
971 echo_char_raw(' ', tty);
972 echo_char_raw('\b', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973 }
974 }
975 }
976 if (kill_type == ERASE)
977 break;
978 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000979 if (tty->read_head == tty->canon_head && L_ECHO(tty))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 finish_erasing(tty);
981}
982
983/**
984 * isig - handle the ISIG optio
985 * @sig: signal
986 * @tty: terminal
987 * @flush: force flush
988 *
989 * Called when a signal is being sent due to terminal input. This
990 * may caus terminal flushing to take place according to the termios
991 * settings and character used. Called from the driver receive_buf
992 * path so serialized.
Alan Cox17b82062008-10-13 10:45:06 +0100993 *
994 * Locking: ctrl_lock, read_lock (both via flush buffer)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 */
Alan Cox4edf1822008-02-08 04:18:44 -0800996
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997static inline void isig(int sig, struct tty_struct *tty, int flush)
998{
Eric W. Biedermanab521dc2007-02-12 00:53:00 -0800999 if (tty->pgrp)
1000 kill_pgrp(tty->pgrp, sig, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001 if (flush || !L_NOFLSH(tty)) {
1002 n_tty_flush_buffer(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001003 tty_driver_flush_buffer(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 }
1005}
1006
1007/**
1008 * n_tty_receive_break - handle break
1009 * @tty: terminal
1010 *
1011 * An RS232 break event has been hit in the incoming bitstream. This
1012 * can cause a variety of events depending upon the termios settings.
1013 *
1014 * Called from the receive_buf path so single threaded.
1015 */
Alan Cox4edf1822008-02-08 04:18:44 -08001016
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017static inline void n_tty_receive_break(struct tty_struct *tty)
1018{
1019 if (I_IGNBRK(tty))
1020 return;
1021 if (I_BRKINT(tty)) {
1022 isig(SIGINT, tty, 1);
1023 return;
1024 }
1025 if (I_PARMRK(tty)) {
1026 put_tty_queue('\377', tty);
1027 put_tty_queue('\0', tty);
1028 }
1029 put_tty_queue('\0', tty);
1030 wake_up_interruptible(&tty->read_wait);
1031}
1032
1033/**
1034 * n_tty_receive_overrun - handle overrun reporting
1035 * @tty: terminal
1036 *
1037 * Data arrived faster than we could process it. While the tty
1038 * driver has flagged this the bits that were missed are gone
1039 * forever.
1040 *
1041 * Called from the receive_buf path so single threaded. Does not
1042 * need locking as num_overrun and overrun_time are function
1043 * private.
1044 */
Alan Cox4edf1822008-02-08 04:18:44 -08001045
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046static inline void n_tty_receive_overrun(struct tty_struct *tty)
1047{
1048 char buf[64];
1049
1050 tty->num_overrun++;
1051 if (time_before(tty->overrun_time, jiffies - HZ) ||
1052 time_after(tty->overrun_time, jiffies)) {
1053 printk(KERN_WARNING "%s: %d input overrun(s)\n",
1054 tty_name(tty, buf),
1055 tty->num_overrun);
1056 tty->overrun_time = jiffies;
1057 tty->num_overrun = 0;
1058 }
1059}
1060
1061/**
1062 * n_tty_receive_parity_error - error notifier
1063 * @tty: terminal device
1064 * @c: character
1065 *
1066 * Process a parity error and queue the right data to indicate
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +02001067 * the error case if necessary. Locking as per n_tty_receive_buf.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068 */
1069static inline void n_tty_receive_parity_error(struct tty_struct *tty,
1070 unsigned char c)
1071{
Alan Cox4edf1822008-02-08 04:18:44 -08001072 if (I_IGNPAR(tty))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 if (I_PARMRK(tty)) {
1075 put_tty_queue('\377', tty);
1076 put_tty_queue('\0', tty);
1077 put_tty_queue(c, tty);
1078 } else if (I_INPCK(tty))
1079 put_tty_queue('\0', tty);
1080 else
1081 put_tty_queue(c, tty);
1082 wake_up_interruptible(&tty->read_wait);
1083}
1084
1085/**
1086 * n_tty_receive_char - perform processing
1087 * @tty: terminal device
1088 * @c: character
1089 *
1090 * Process an individual character of input received from the driver.
Alan Cox4edf1822008-02-08 04:18:44 -08001091 * This is serialized with respect to itself by the rules for the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 * driver above.
1093 */
1094
1095static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
1096{
1097 unsigned long flags;
Joe Petersonacc71bb2009-01-02 13:43:32 +00001098 int parmrk;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099
1100 if (tty->raw) {
1101 put_tty_queue(c, tty);
1102 return;
1103 }
Alan Cox4edf1822008-02-08 04:18:44 -08001104
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105 if (I_ISTRIP(tty))
1106 c &= 0x7f;
1107 if (I_IUCLC(tty) && L_IEXTEN(tty))
Alan Cox300a6202009-01-02 13:41:04 +00001108 c = tolower(c);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001109
hyc@symas.com26df6d12010-06-22 10:14:49 -07001110 if (L_EXTPROC(tty)) {
1111 put_tty_queue(c, tty);
1112 return;
1113 }
1114
Joe Peterson54d2a372008-02-06 01:37:59 -08001115 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) &&
Joe Petersona88a69c2009-01-02 13:40:53 +00001116 I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) &&
1117 c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) {
Joe Peterson54d2a372008-02-06 01:37:59 -08001118 start_tty(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001119 process_echoes(tty);
1120 }
Joe Peterson54d2a372008-02-06 01:37:59 -08001121
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122 if (tty->closing) {
1123 if (I_IXON(tty)) {
Joe Petersona88a69c2009-01-02 13:40:53 +00001124 if (c == START_CHAR(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001125 start_tty(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001126 process_echoes(tty);
Alan Cox300a6202009-01-02 13:41:04 +00001127 } else if (c == STOP_CHAR(tty))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128 stop_tty(tty);
1129 }
1130 return;
1131 }
1132
1133 /*
1134 * If the previous character was LNEXT, or we know that this
1135 * character is not one of the characters that we'll have to
1136 * handle specially, do shortcut processing to speed things
1137 * up.
1138 */
1139 if (!test_bit(c, tty->process_char_map) || tty->lnext) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140 tty->lnext = 0;
Joe Petersonacc71bb2009-01-02 13:43:32 +00001141 parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
1142 if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
1143 /* beep if no space */
Joe Peterson7e94b1d2009-01-02 13:43:40 +00001144 if (L_ECHO(tty))
1145 process_output('\a', tty);
Joe Petersonacc71bb2009-01-02 13:43:32 +00001146 return;
1147 }
1148 if (L_ECHO(tty)) {
1149 finish_erasing(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150 /* Record the column of first canon char. */
1151 if (tty->canon_head == tty->read_head)
Joe Petersona88a69c2009-01-02 13:40:53 +00001152 echo_set_canon_col(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153 echo_char(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001154 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 }
Joe Petersonacc71bb2009-01-02 13:43:32 +00001156 if (parmrk)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001157 put_tty_queue(c, tty);
1158 put_tty_queue(c, tty);
1159 return;
1160 }
Alan Cox4edf1822008-02-08 04:18:44 -08001161
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 if (I_IXON(tty)) {
1163 if (c == START_CHAR(tty)) {
1164 start_tty(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001165 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166 return;
1167 }
1168 if (c == STOP_CHAR(tty)) {
1169 stop_tty(tty);
1170 return;
1171 }
1172 }
Joe Peterson575537b32008-04-30 00:53:30 -07001173
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 if (L_ISIG(tty)) {
1175 int signal;
1176 signal = SIGINT;
1177 if (c == INTR_CHAR(tty))
1178 goto send_signal;
1179 signal = SIGQUIT;
1180 if (c == QUIT_CHAR(tty))
1181 goto send_signal;
1182 signal = SIGTSTP;
1183 if (c == SUSP_CHAR(tty)) {
1184send_signal:
Joe Petersonec5b1152008-02-06 01:37:38 -08001185 /*
Joe Petersonec5b1152008-02-06 01:37:38 -08001186 * Note that we do not use isig() here because we want
1187 * the order to be:
1188 * 1) flush, 2) echo, 3) signal
1189 */
1190 if (!L_NOFLSH(tty)) {
1191 n_tty_flush_buffer(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001192 tty_driver_flush_buffer(tty);
Joe Petersonec5b1152008-02-06 01:37:38 -08001193 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001194 if (I_IXON(tty))
1195 start_tty(tty);
1196 if (L_ECHO(tty)) {
Joe Petersonec5b1152008-02-06 01:37:38 -08001197 echo_char(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001198 process_echoes(tty);
1199 }
Joe Petersonec5b1152008-02-06 01:37:38 -08001200 if (tty->pgrp)
1201 kill_pgrp(tty->pgrp, signal, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202 return;
1203 }
1204 }
Joe Peterson575537b32008-04-30 00:53:30 -07001205
1206 if (c == '\r') {
1207 if (I_IGNCR(tty))
1208 return;
1209 if (I_ICRNL(tty))
1210 c = '\n';
1211 } else if (c == '\n' && I_INLCR(tty))
1212 c = '\r';
1213
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214 if (tty->icanon) {
1215 if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
1216 (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
1217 eraser(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001218 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219 return;
1220 }
1221 if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
1222 tty->lnext = 1;
1223 if (L_ECHO(tty)) {
1224 finish_erasing(tty);
1225 if (L_ECHOCTL(tty)) {
Joe Petersona88a69c2009-01-02 13:40:53 +00001226 echo_char_raw('^', tty);
1227 echo_char_raw('\b', tty);
1228 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229 }
1230 }
1231 return;
1232 }
1233 if (c == REPRINT_CHAR(tty) && L_ECHO(tty) &&
1234 L_IEXTEN(tty)) {
1235 unsigned long tail = tty->canon_head;
1236
1237 finish_erasing(tty);
1238 echo_char(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001239 echo_char_raw('\n', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 while (tail != tty->read_head) {
1241 echo_char(tty->read_buf[tail], tty);
1242 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
1243 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001244 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245 return;
1246 }
1247 if (c == '\n') {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001248 if (tty->read_cnt >= N_TTY_BUF_SIZE) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +00001249 if (L_ECHO(tty))
1250 process_output('\a', tty);
Joe Petersonacc71bb2009-01-02 13:43:32 +00001251 return;
1252 }
1253 if (L_ECHO(tty) || L_ECHONL(tty)) {
Joe Petersona88a69c2009-01-02 13:40:53 +00001254 echo_char_raw('\n', tty);
1255 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 }
1257 goto handle_newline;
1258 }
1259 if (c == EOF_CHAR(tty)) {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001260 if (tty->read_cnt >= N_TTY_BUF_SIZE)
1261 return;
Alan Cox4edf1822008-02-08 04:18:44 -08001262 if (tty->canon_head != tty->read_head)
1263 set_bit(TTY_PUSH, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264 c = __DISABLED_CHAR;
1265 goto handle_newline;
1266 }
1267 if ((c == EOL_CHAR(tty)) ||
1268 (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001269 parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty))
1270 ? 1 : 0;
1271 if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +00001272 if (L_ECHO(tty))
1273 process_output('\a', tty);
Joe Petersonacc71bb2009-01-02 13:43:32 +00001274 return;
1275 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276 /*
1277 * XXX are EOL_CHAR and EOL2_CHAR echoed?!?
1278 */
1279 if (L_ECHO(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280 /* Record the column of first canon char. */
1281 if (tty->canon_head == tty->read_head)
Joe Petersona88a69c2009-01-02 13:40:53 +00001282 echo_set_canon_col(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283 echo_char(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001284 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285 }
1286 /*
1287 * XXX does PARMRK doubling happen for
1288 * EOL_CHAR and EOL2_CHAR?
1289 */
Joe Petersonacc71bb2009-01-02 13:43:32 +00001290 if (parmrk)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291 put_tty_queue(c, tty);
1292
Alan Cox4edf1822008-02-08 04:18:44 -08001293handle_newline:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294 spin_lock_irqsave(&tty->read_lock, flags);
1295 set_bit(tty->read_head, tty->read_flags);
1296 put_tty_queue_nolock(c, tty);
1297 tty->canon_head = tty->read_head;
1298 tty->canon_data++;
1299 spin_unlock_irqrestore(&tty->read_lock, flags);
1300 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
1301 if (waitqueue_active(&tty->read_wait))
1302 wake_up_interruptible(&tty->read_wait);
1303 return;
1304 }
1305 }
Alan Cox4edf1822008-02-08 04:18:44 -08001306
Joe Petersonacc71bb2009-01-02 13:43:32 +00001307 parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
1308 if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
1309 /* beep if no space */
Joe Peterson7e94b1d2009-01-02 13:43:40 +00001310 if (L_ECHO(tty))
1311 process_output('\a', tty);
Joe Petersonacc71bb2009-01-02 13:43:32 +00001312 return;
1313 }
1314 if (L_ECHO(tty)) {
1315 finish_erasing(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001316 if (c == '\n')
Joe Petersona88a69c2009-01-02 13:40:53 +00001317 echo_char_raw('\n', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 else {
1319 /* Record the column of first canon char. */
1320 if (tty->canon_head == tty->read_head)
Joe Petersona88a69c2009-01-02 13:40:53 +00001321 echo_set_canon_col(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 echo_char(c, tty);
1323 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001324 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325 }
1326
Joe Petersonacc71bb2009-01-02 13:43:32 +00001327 if (parmrk)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 put_tty_queue(c, tty);
1329
1330 put_tty_queue(c, tty);
Alan Cox4edf1822008-02-08 04:18:44 -08001331}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333
1334/**
1335 * n_tty_write_wakeup - asynchronous I/O notifier
1336 * @tty: tty device
1337 *
1338 * Required for the ptys, serial driver etc. since processes
1339 * that attach themselves to the master and rely on ASYNC
1340 * IO must be woken up
1341 */
1342
1343static void n_tty_write_wakeup(struct tty_struct *tty)
1344{
Thomas Pfaffff8cb0f2009-01-02 13:47:13 +00001345 if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346 kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347}
1348
1349/**
1350 * n_tty_receive_buf - data receive
1351 * @tty: terminal device
1352 * @cp: buffer
1353 * @fp: flag buffer
1354 * @count: characters
1355 *
1356 * Called by the terminal driver when a block of characters has
1357 * been received. This function must be called from soft contexts
1358 * not from interrupt context. The driver is responsible for making
1359 * calls one at a time and in order (or using flush_to_ldisc)
1360 */
Alan Cox4edf1822008-02-08 04:18:44 -08001361
Linus Torvalds55db4c62011-06-04 06:33:24 +09001362static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1363 char *fp, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364{
1365 const unsigned char *p;
1366 char *f, flags = TTY_NORMAL;
1367 int i;
1368 char buf[64];
1369 unsigned long cpuflags;
1370
1371 if (!tty->read_buf)
Linus Torvalds55db4c62011-06-04 06:33:24 +09001372 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001373
1374 if (tty->real_raw) {
1375 spin_lock_irqsave(&tty->read_lock, cpuflags);
1376 i = min(N_TTY_BUF_SIZE - tty->read_cnt,
1377 N_TTY_BUF_SIZE - tty->read_head);
1378 i = min(count, i);
1379 memcpy(tty->read_buf + tty->read_head, cp, i);
1380 tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
1381 tty->read_cnt += i;
1382 cp += i;
1383 count -= i;
1384
1385 i = min(N_TTY_BUF_SIZE - tty->read_cnt,
1386 N_TTY_BUF_SIZE - tty->read_head);
1387 i = min(count, i);
1388 memcpy(tty->read_buf + tty->read_head, cp, i);
1389 tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
1390 tty->read_cnt += i;
1391 spin_unlock_irqrestore(&tty->read_lock, cpuflags);
1392 } else {
Alan Cox4edf1822008-02-08 04:18:44 -08001393 for (i = count, p = cp, f = fp; i; i--, p++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394 if (f)
1395 flags = *f++;
1396 switch (flags) {
1397 case TTY_NORMAL:
1398 n_tty_receive_char(tty, *p);
1399 break;
1400 case TTY_BREAK:
1401 n_tty_receive_break(tty);
1402 break;
1403 case TTY_PARITY:
1404 case TTY_FRAME:
1405 n_tty_receive_parity_error(tty, *p);
1406 break;
1407 case TTY_OVERRUN:
1408 n_tty_receive_overrun(tty);
1409 break;
1410 default:
Alan Cox4edf1822008-02-08 04:18:44 -08001411 printk(KERN_ERR "%s: unknown flag %d\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412 tty_name(tty, buf), flags);
1413 break;
1414 }
1415 }
Alan Coxf34d7a52008-04-30 00:54:13 -07001416 if (tty->ops->flush_chars)
1417 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418 }
1419
Linus Torvalds55db4c62011-06-04 06:33:24 +09001420 n_tty_set_room(tty);
1421
hyc@symas.com26df6d12010-06-22 10:14:49 -07001422 if ((!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) ||
1423 L_EXTPROC(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
1425 if (waitqueue_active(&tty->read_wait))
1426 wake_up_interruptible(&tty->read_wait);
1427 }
1428
1429 /*
1430 * Check the remaining room for the input canonicalization
1431 * mode. We don't want to throttle the driver if we're in
1432 * canonical mode and don't have a newline yet!
1433 */
Linus Torvalds55db4c62011-06-04 06:33:24 +09001434 if (tty->receive_room < TTY_THRESHOLD_THROTTLE)
Alan Cox39c2e602008-04-30 00:54:18 -07001435 tty_throttle(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001436}
1437
1438int is_ignored(int sig)
1439{
1440 return (sigismember(&current->blocked, sig) ||
Alan Cox4edf1822008-02-08 04:18:44 -08001441 current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442}
1443
1444/**
1445 * n_tty_set_termios - termios data changed
1446 * @tty: terminal
1447 * @old: previous data
1448 *
1449 * Called by the tty layer when the user changes termios flags so
1450 * that the line discipline can plan ahead. This function cannot sleep
Alan Cox4edf1822008-02-08 04:18:44 -08001451 * and is protected from re-entry by the tty layer. The user is
Linus Torvalds1da177e2005-04-16 15:20:36 -07001452 * guaranteed that this function will not be re-entered or in progress
1453 * when the ldisc is closed.
Alan Cox17b82062008-10-13 10:45:06 +01001454 *
1455 * Locking: Caller holds tty->termios_mutex
Linus Torvalds1da177e2005-04-16 15:20:36 -07001456 */
Alan Cox4edf1822008-02-08 04:18:44 -08001457
1458static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459{
Alan Cox47afa7a2008-10-13 10:44:17 +01001460 int canon_change = 1;
1461 BUG_ON(!tty);
1462
1463 if (old)
1464 canon_change = (old->c_lflag ^ tty->termios->c_lflag) & ICANON;
1465 if (canon_change) {
1466 memset(&tty->read_flags, 0, sizeof tty->read_flags);
1467 tty->canon_head = tty->read_tail;
1468 tty->canon_data = 0;
1469 tty->erasing = 0;
1470 }
1471
1472 if (canon_change && !L_ICANON(tty) && tty->read_cnt)
1473 wake_up_interruptible(&tty->read_wait);
Alan Cox4edf1822008-02-08 04:18:44 -08001474
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475 tty->icanon = (L_ICANON(tty) != 0);
1476 if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
1477 tty->raw = 1;
1478 tty->real_raw = 1;
Linus Torvalds55db4c62011-06-04 06:33:24 +09001479 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480 return;
1481 }
1482 if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
1483 I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
1484 I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
1485 I_PARMRK(tty)) {
1486 memset(tty->process_char_map, 0, 256/8);
1487
1488 if (I_IGNCR(tty) || I_ICRNL(tty))
1489 set_bit('\r', tty->process_char_map);
1490 if (I_INLCR(tty))
1491 set_bit('\n', tty->process_char_map);
1492
1493 if (L_ICANON(tty)) {
1494 set_bit(ERASE_CHAR(tty), tty->process_char_map);
1495 set_bit(KILL_CHAR(tty), tty->process_char_map);
1496 set_bit(EOF_CHAR(tty), tty->process_char_map);
1497 set_bit('\n', tty->process_char_map);
1498 set_bit(EOL_CHAR(tty), tty->process_char_map);
1499 if (L_IEXTEN(tty)) {
1500 set_bit(WERASE_CHAR(tty),
1501 tty->process_char_map);
1502 set_bit(LNEXT_CHAR(tty),
1503 tty->process_char_map);
1504 set_bit(EOL2_CHAR(tty),
1505 tty->process_char_map);
1506 if (L_ECHO(tty))
1507 set_bit(REPRINT_CHAR(tty),
1508 tty->process_char_map);
1509 }
1510 }
1511 if (I_IXON(tty)) {
1512 set_bit(START_CHAR(tty), tty->process_char_map);
1513 set_bit(STOP_CHAR(tty), tty->process_char_map);
1514 }
1515 if (L_ISIG(tty)) {
1516 set_bit(INTR_CHAR(tty), tty->process_char_map);
1517 set_bit(QUIT_CHAR(tty), tty->process_char_map);
1518 set_bit(SUSP_CHAR(tty), tty->process_char_map);
1519 }
1520 clear_bit(__DISABLED_CHAR, tty->process_char_map);
1521 tty->raw = 0;
1522 tty->real_raw = 0;
1523 } else {
1524 tty->raw = 1;
1525 if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
1526 (I_IGNPAR(tty) || !I_INPCK(tty)) &&
1527 (tty->driver->flags & TTY_DRIVER_REAL_RAW))
1528 tty->real_raw = 1;
1529 else
1530 tty->real_raw = 0;
1531 }
Linus Torvalds55db4c62011-06-04 06:33:24 +09001532 n_tty_set_room(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001533 /* The termios change make the tty ready for I/O */
1534 wake_up_interruptible(&tty->write_wait);
1535 wake_up_interruptible(&tty->read_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536}
1537
1538/**
1539 * n_tty_close - close the ldisc for this tty
1540 * @tty: device
1541 *
Alan Cox4edf1822008-02-08 04:18:44 -08001542 * Called from the terminal layer when this line discipline is
1543 * being shut down, either because of a close or becsuse of a
Linus Torvalds1da177e2005-04-16 15:20:36 -07001544 * discipline change. The function will not be called while other
1545 * ldisc methods are in progress.
1546 */
Alan Cox4edf1822008-02-08 04:18:44 -08001547
Linus Torvalds1da177e2005-04-16 15:20:36 -07001548static void n_tty_close(struct tty_struct *tty)
1549{
1550 n_tty_flush_buffer(tty);
1551 if (tty->read_buf) {
Alan Cox0b4068a2009-06-11 13:05:49 +01001552 kfree(tty->read_buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001553 tty->read_buf = NULL;
1554 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001555 if (tty->echo_buf) {
Alan Cox0b4068a2009-06-11 13:05:49 +01001556 kfree(tty->echo_buf);
Joe Petersona88a69c2009-01-02 13:40:53 +00001557 tty->echo_buf = NULL;
1558 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001559}
1560
1561/**
1562 * n_tty_open - open an ldisc
1563 * @tty: terminal to open
1564 *
Alan Cox4edf1822008-02-08 04:18:44 -08001565 * Called when this line discipline is being attached to the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566 * terminal device. Can sleep. Called serialized so that no
1567 * other events will occur in parallel. No further open will occur
1568 * until a close.
1569 */
1570
1571static int n_tty_open(struct tty_struct *tty)
1572{
1573 if (!tty)
1574 return -EINVAL;
1575
Joe Petersona88a69c2009-01-02 13:40:53 +00001576 /* These are ugly. Currently a malloc failure here can panic */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001577 if (!tty->read_buf) {
Alan Cox0b4068a2009-06-11 13:05:49 +01001578 tty->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001579 if (!tty->read_buf)
1580 return -ENOMEM;
1581 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001582 if (!tty->echo_buf) {
Alan Cox0b4068a2009-06-11 13:05:49 +01001583 tty->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
1584
Joe Petersona88a69c2009-01-02 13:40:53 +00001585 if (!tty->echo_buf)
1586 return -ENOMEM;
1587 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001588 reset_buffer_flags(tty);
Andrew McGregor7b292b42011-06-13 11:31:31 +12001589 tty_unthrottle(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001590 tty->column = 0;
1591 n_tty_set_termios(tty, NULL);
1592 tty->minimum_to_wake = 1;
1593 tty->closing = 0;
1594 return 0;
1595}
1596
1597static inline int input_available_p(struct tty_struct *tty, int amt)
1598{
OGAWA Hirofumie043e422009-07-29 12:15:56 -07001599 tty_flush_to_ldisc(tty);
hyc@symas.com26df6d12010-06-22 10:14:49 -07001600 if (tty->icanon && !L_EXTPROC(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001601 if (tty->canon_data)
1602 return 1;
1603 } else if (tty->read_cnt >= (amt ? amt : 1))
1604 return 1;
1605
1606 return 0;
1607}
1608
1609/**
1610 * copy_from_read_buf - copy read data directly
1611 * @tty: terminal device
1612 * @b: user data
1613 * @nr: size of data
1614 *
Alan Cox11a96d12008-10-13 10:46:24 +01001615 * Helper function to speed up n_tty_read. It is only called when
Linus Torvalds1da177e2005-04-16 15:20:36 -07001616 * ICANON is off; it copies characters straight from the tty queue to
1617 * user space directly. It can be profitably called twice; once to
1618 * drain the space from the tail pointer to the (physical) end of the
1619 * buffer, and once to drain the space from the (physical) beginning of
1620 * the buffer to head pointer.
1621 *
Paul Fulghum817d6d32006-06-28 04:26:47 -07001622 * Called under the tty->atomic_read_lock sem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001623 *
1624 */
Alan Cox4edf1822008-02-08 04:18:44 -08001625
Alan Cox33f0f882006-01-09 20:54:13 -08001626static int copy_from_read_buf(struct tty_struct *tty,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001627 unsigned char __user **b,
1628 size_t *nr)
1629
1630{
1631 int retval;
1632 size_t n;
1633 unsigned long flags;
1634
1635 retval = 0;
1636 spin_lock_irqsave(&tty->read_lock, flags);
1637 n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail);
1638 n = min(*nr, n);
1639 spin_unlock_irqrestore(&tty->read_lock, flags);
1640 if (n) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001641 retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n);
1642 n -= retval;
Miloslav Trmac522ed772007-07-15 23:40:56 -07001643 tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001644 spin_lock_irqsave(&tty->read_lock, flags);
1645 tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1);
1646 tty->read_cnt -= n;
hyc@symas.com26df6d12010-06-22 10:14:49 -07001647 /* Turn single EOF into zero-length read */
1648 if (L_EXTPROC(tty) && tty->icanon && n == 1) {
1649 if (!tty->read_cnt && (*b)[n-1] == EOF_CHAR(tty))
1650 n--;
1651 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001652 spin_unlock_irqrestore(&tty->read_lock, flags);
1653 *b += n;
1654 *nr -= n;
1655 }
1656 return retval;
1657}
1658
Al Virocc4191d2008-03-29 03:08:48 +00001659extern ssize_t redirected_tty_write(struct file *, const char __user *,
Alan Cox4edf1822008-02-08 04:18:44 -08001660 size_t, loff_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001661
1662/**
1663 * job_control - check job control
1664 * @tty: tty
1665 * @file: file handle
1666 *
1667 * Perform job control management checks on this file/tty descriptor
Alan Cox4edf1822008-02-08 04:18:44 -08001668 * and if appropriate send any needed signals and return a negative
Linus Torvalds1da177e2005-04-16 15:20:36 -07001669 * error code if action should be taken.
Alan Cox04f378b2008-04-30 00:53:29 -07001670 *
1671 * FIXME:
1672 * Locking: None - redirected write test is safe, testing
1673 * current->signal should possibly lock current->sighand
1674 * pgrp locking ?
Linus Torvalds1da177e2005-04-16 15:20:36 -07001675 */
Alan Cox4edf1822008-02-08 04:18:44 -08001676
Linus Torvalds1da177e2005-04-16 15:20:36 -07001677static int job_control(struct tty_struct *tty, struct file *file)
1678{
1679 /* Job control check -- must be done at start and after
1680 every sleep (POSIX.1 7.1.1.4). */
1681 /* NOTE: not yet done after every sleep pending a thorough
1682 check of the logic of this change. -- jlc */
1683 /* don't stop on /dev/console */
1684 if (file->f_op->write != redirected_tty_write &&
1685 current->signal->tty == tty) {
Eric W. Biedermanab521dc2007-02-12 00:53:00 -08001686 if (!tty->pgrp)
Alan Cox11a96d12008-10-13 10:46:24 +01001687 printk(KERN_ERR "n_tty_read: no tty->pgrp!\n");
Eric W. Biedermanab521dc2007-02-12 00:53:00 -08001688 else if (task_pgrp(current) != tty->pgrp) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001689 if (is_ignored(SIGTTIN) ||
Eric W. Biederman3e7cd6c2007-02-12 00:52:58 -08001690 is_current_pgrp_orphaned())
Linus Torvalds1da177e2005-04-16 15:20:36 -07001691 return -EIO;
Eric W. Biedermanab521dc2007-02-12 00:53:00 -08001692 kill_pgrp(task_pgrp(current), SIGTTIN, 1);
Oleg Nesterov040b6362007-06-01 00:46:53 -07001693 set_thread_flag(TIF_SIGPENDING);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694 return -ERESTARTSYS;
1695 }
1696 }
1697 return 0;
1698}
Alan Cox4edf1822008-02-08 04:18:44 -08001699
Linus Torvalds1da177e2005-04-16 15:20:36 -07001700
1701/**
Alan Cox11a96d12008-10-13 10:46:24 +01001702 * n_tty_read - read function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07001703 * @tty: tty device
1704 * @file: file object
1705 * @buf: userspace buffer pointer
1706 * @nr: size of I/O
1707 *
1708 * Perform reads for the line discipline. We are guaranteed that the
1709 * line discipline will not be closed under us but we may get multiple
1710 * parallel readers and must handle this ourselves. We may also get
1711 * a hangup. Always called in user context, may sleep.
1712 *
1713 * This code must be sure never to sleep through a hangup.
1714 */
Alan Cox4edf1822008-02-08 04:18:44 -08001715
Alan Cox11a96d12008-10-13 10:46:24 +01001716static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001717 unsigned char __user *buf, size_t nr)
1718{
1719 unsigned char __user *b = buf;
1720 DECLARE_WAITQUEUE(wait, current);
1721 int c;
1722 int minimum, time;
1723 ssize_t retval = 0;
1724 ssize_t size;
1725 long timeout;
1726 unsigned long flags;
Alan Cox04f378b2008-04-30 00:53:29 -07001727 int packet;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001728
1729do_it_again:
1730
Alan Cox17b82062008-10-13 10:45:06 +01001731 BUG_ON(!tty->read_buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732
1733 c = job_control(tty, file);
Alan Cox4edf1822008-02-08 04:18:44 -08001734 if (c < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735 return c;
Alan Cox4edf1822008-02-08 04:18:44 -08001736
Linus Torvalds1da177e2005-04-16 15:20:36 -07001737 minimum = time = 0;
1738 timeout = MAX_SCHEDULE_TIMEOUT;
1739 if (!tty->icanon) {
1740 time = (HZ / 10) * TIME_CHAR(tty);
1741 minimum = MIN_CHAR(tty);
1742 if (minimum) {
1743 if (time)
1744 tty->minimum_to_wake = 1;
1745 else if (!waitqueue_active(&tty->read_wait) ||
1746 (tty->minimum_to_wake > minimum))
1747 tty->minimum_to_wake = minimum;
1748 } else {
1749 timeout = 0;
1750 if (time) {
1751 timeout = time;
1752 time = 0;
1753 }
1754 tty->minimum_to_wake = minimum = 1;
1755 }
1756 }
1757
1758 /*
1759 * Internal serialization of reads.
1760 */
1761 if (file->f_flags & O_NONBLOCK) {
Ingo Molnar70522e12006-03-23 03:00:31 -08001762 if (!mutex_trylock(&tty->atomic_read_lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001763 return -EAGAIN;
Alan Cox4edf1822008-02-08 04:18:44 -08001764 } else {
Ingo Molnar70522e12006-03-23 03:00:31 -08001765 if (mutex_lock_interruptible(&tty->atomic_read_lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001766 return -ERESTARTSYS;
1767 }
Alan Cox04f378b2008-04-30 00:53:29 -07001768 packet = tty->packet;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001769
1770 add_wait_queue(&tty->read_wait, &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001771 while (nr) {
1772 /* First test for status change. */
Alan Cox04f378b2008-04-30 00:53:29 -07001773 if (packet && tty->link->ctrl_status) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001774 unsigned char cs;
1775 if (b != buf)
1776 break;
Alan Cox04f378b2008-04-30 00:53:29 -07001777 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 cs = tty->link->ctrl_status;
1779 tty->link->ctrl_status = 0;
Alan Cox04f378b2008-04-30 00:53:29 -07001780 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
Miloslav Trmac522ed772007-07-15 23:40:56 -07001781 if (tty_put_user(tty, cs, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001782 retval = -EFAULT;
1783 b--;
1784 break;
1785 }
1786 nr--;
1787 break;
1788 }
1789 /* This statement must be first before checking for input
1790 so that any interrupt will set the state back to
1791 TASK_RUNNING. */
1792 set_current_state(TASK_INTERRUPTIBLE);
Alan Cox4edf1822008-02-08 04:18:44 -08001793
Linus Torvalds1da177e2005-04-16 15:20:36 -07001794 if (((minimum - (b - buf)) < tty->minimum_to_wake) &&
1795 ((minimum - (b - buf)) >= 1))
1796 tty->minimum_to_wake = (minimum - (b - buf));
Alan Cox4edf1822008-02-08 04:18:44 -08001797
Linus Torvalds1da177e2005-04-16 15:20:36 -07001798 if (!input_available_p(tty, 0)) {
1799 if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
1800 retval = -EIO;
1801 break;
1802 }
1803 if (tty_hung_up_p(file))
1804 break;
1805 if (!timeout)
1806 break;
1807 if (file->f_flags & O_NONBLOCK) {
1808 retval = -EAGAIN;
1809 break;
1810 }
1811 if (signal_pending(current)) {
1812 retval = -ERESTARTSYS;
1813 break;
1814 }
Linus Torvalds55db4c62011-06-04 06:33:24 +09001815 /* FIXME: does n_tty_set_room need locking ? */
1816 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001817 timeout = schedule_timeout(timeout);
Jiri Slaby28726282011-06-05 14:16:17 +02001818 BUG_ON(!tty->read_buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001819 continue;
1820 }
1821 __set_current_state(TASK_RUNNING);
1822
1823 /* Deal with packet mode. */
Alan Cox04f378b2008-04-30 00:53:29 -07001824 if (packet && b == buf) {
Miloslav Trmac522ed772007-07-15 23:40:56 -07001825 if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826 retval = -EFAULT;
1827 b--;
1828 break;
1829 }
1830 nr--;
1831 }
1832
hyc@symas.com26df6d12010-06-22 10:14:49 -07001833 if (tty->icanon && !L_EXTPROC(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834 /* N.B. avoid overrun if nr == 0 */
1835 while (nr && tty->read_cnt) {
Alan Cox4edf1822008-02-08 04:18:44 -08001836 int eol;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001837
1838 eol = test_and_clear_bit(tty->read_tail,
1839 tty->read_flags);
1840 c = tty->read_buf[tty->read_tail];
1841 spin_lock_irqsave(&tty->read_lock, flags);
1842 tty->read_tail = ((tty->read_tail+1) &
1843 (N_TTY_BUF_SIZE-1));
1844 tty->read_cnt--;
1845 if (eol) {
1846 /* this test should be redundant:
1847 * we shouldn't be reading data if
1848 * canon_data is 0
1849 */
1850 if (--tty->canon_data < 0)
1851 tty->canon_data = 0;
1852 }
1853 spin_unlock_irqrestore(&tty->read_lock, flags);
1854
1855 if (!eol || (c != __DISABLED_CHAR)) {
Miloslav Trmac522ed772007-07-15 23:40:56 -07001856 if (tty_put_user(tty, c, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857 retval = -EFAULT;
1858 b--;
1859 break;
1860 }
1861 nr--;
1862 }
Miloslav Trmac522ed772007-07-15 23:40:56 -07001863 if (eol) {
1864 tty_audit_push(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001865 break;
Miloslav Trmac522ed772007-07-15 23:40:56 -07001866 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867 }
1868 if (retval)
1869 break;
1870 } else {
1871 int uncopied;
Alan Cox04f378b2008-04-30 00:53:29 -07001872 /* The copy function takes the read lock and handles
1873 locking internally for this case */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001874 uncopied = copy_from_read_buf(tty, &b, &nr);
1875 uncopied += copy_from_read_buf(tty, &b, &nr);
1876 if (uncopied) {
1877 retval = -EFAULT;
1878 break;
1879 }
1880 }
1881
1882 /* If there is enough space in the read buffer now, let the
1883 * low-level driver know. We use n_tty_chars_in_buffer() to
1884 * check the buffer, as it now knows about canonical mode.
1885 * Otherwise, if the driver is throttled and the line is
1886 * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
1887 * we won't get any more characters.
1888 */
Linus Torvalds55db4c62011-06-04 06:33:24 +09001889 if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) {
1890 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891 check_unthrottle(tty);
Linus Torvalds55db4c62011-06-04 06:33:24 +09001892 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893
1894 if (b - buf >= minimum)
1895 break;
1896 if (time)
1897 timeout = time;
1898 }
Ingo Molnar70522e12006-03-23 03:00:31 -08001899 mutex_unlock(&tty->atomic_read_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001900 remove_wait_queue(&tty->read_wait, &wait);
1901
1902 if (!waitqueue_active(&tty->read_wait))
1903 tty->minimum_to_wake = minimum;
1904
1905 __set_current_state(TASK_RUNNING);
1906 size = b - buf;
1907 if (size) {
1908 retval = size;
1909 if (nr)
Alan Cox4edf1822008-02-08 04:18:44 -08001910 clear_bit(TTY_PUSH, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001911 } else if (test_and_clear_bit(TTY_PUSH, &tty->flags))
1912 goto do_it_again;
1913
Linus Torvalds55db4c62011-06-04 06:33:24 +09001914 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001915 return retval;
1916}
1917
1918/**
Alan Cox11a96d12008-10-13 10:46:24 +01001919 * n_tty_write - write function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07001920 * @tty: tty device
1921 * @file: file object
1922 * @buf: userspace buffer pointer
1923 * @nr: size of I/O
1924 *
Joe Petersona88a69c2009-01-02 13:40:53 +00001925 * Write function of the terminal device. This is serialized with
Linus Torvalds1da177e2005-04-16 15:20:36 -07001926 * respect to other write callers but not to termios changes, reads
Joe Petersona88a69c2009-01-02 13:40:53 +00001927 * and other such events. Since the receive code will echo characters,
1928 * thus calling driver write methods, the output_lock is used in
1929 * the output processing functions called here as well as in the
1930 * echo processing function to protect the column state and space
1931 * left in the buffer.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001932 *
1933 * This code must be sure never to sleep through a hangup.
Joe Petersona88a69c2009-01-02 13:40:53 +00001934 *
1935 * Locking: output_lock to protect column state and space left
1936 * (note that the process_output*() functions take this
1937 * lock themselves)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001938 */
Alan Cox4edf1822008-02-08 04:18:44 -08001939
Alan Cox11a96d12008-10-13 10:46:24 +01001940static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
Joe Petersona88a69c2009-01-02 13:40:53 +00001941 const unsigned char *buf, size_t nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001942{
1943 const unsigned char *b = buf;
1944 DECLARE_WAITQUEUE(wait, current);
1945 int c;
1946 ssize_t retval = 0;
1947
1948 /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
1949 if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) {
1950 retval = tty_check_change(tty);
1951 if (retval)
1952 return retval;
1953 }
1954
Joe Petersona88a69c2009-01-02 13:40:53 +00001955 /* Write out any echoed characters that are still pending */
1956 process_echoes(tty);
Alan Cox300a6202009-01-02 13:41:04 +00001957
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958 add_wait_queue(&tty->write_wait, &wait);
1959 while (1) {
1960 set_current_state(TASK_INTERRUPTIBLE);
1961 if (signal_pending(current)) {
1962 retval = -ERESTARTSYS;
1963 break;
1964 }
1965 if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) {
1966 retval = -EIO;
1967 break;
1968 }
1969 if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
1970 while (nr > 0) {
Joe Petersona88a69c2009-01-02 13:40:53 +00001971 ssize_t num = process_output_block(tty, b, nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972 if (num < 0) {
1973 if (num == -EAGAIN)
1974 break;
1975 retval = num;
1976 goto break_out;
1977 }
1978 b += num;
1979 nr -= num;
1980 if (nr == 0)
1981 break;
1982 c = *b;
Joe Petersona88a69c2009-01-02 13:40:53 +00001983 if (process_output(c, tty) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001984 break;
1985 b++; nr--;
1986 }
Alan Coxf34d7a52008-04-30 00:54:13 -07001987 if (tty->ops->flush_chars)
1988 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001989 } else {
Roman Zippeld6afe272005-07-07 17:56:55 -07001990 while (nr > 0) {
Alan Coxf34d7a52008-04-30 00:54:13 -07001991 c = tty->ops->write(tty, b, nr);
Roman Zippeld6afe272005-07-07 17:56:55 -07001992 if (c < 0) {
1993 retval = c;
1994 goto break_out;
1995 }
1996 if (!c)
1997 break;
1998 b += c;
1999 nr -= c;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002000 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002001 }
2002 if (!nr)
2003 break;
2004 if (file->f_flags & O_NONBLOCK) {
2005 retval = -EAGAIN;
2006 break;
2007 }
2008 schedule();
2009 }
2010break_out:
2011 __set_current_state(TASK_RUNNING);
2012 remove_wait_queue(&tty->write_wait, &wait);
Thomas Pfaffff8cb0f2009-01-02 13:47:13 +00002013 if (b - buf != nr && tty->fasync)
2014 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002015 return (b - buf) ? b - buf : retval;
2016}
2017
2018/**
Alan Cox11a96d12008-10-13 10:46:24 +01002019 * n_tty_poll - poll method for N_TTY
Linus Torvalds1da177e2005-04-16 15:20:36 -07002020 * @tty: terminal device
2021 * @file: file accessing it
2022 * @wait: poll table
2023 *
2024 * Called when the line discipline is asked to poll() for data or
2025 * for special events. This code is not serialized with respect to
2026 * other events save open/close.
2027 *
2028 * This code must be sure never to sleep through a hangup.
2029 * Called without the kernel lock held - fine
Linus Torvalds1da177e2005-04-16 15:20:36 -07002030 */
Alan Cox4edf1822008-02-08 04:18:44 -08002031
Alan Cox11a96d12008-10-13 10:46:24 +01002032static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
Alan Cox4edf1822008-02-08 04:18:44 -08002033 poll_table *wait)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002034{
2035 unsigned int mask = 0;
2036
2037 poll_wait(file, &tty->read_wait, wait);
2038 poll_wait(file, &tty->write_wait, wait);
2039 if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty)))
2040 mask |= POLLIN | POLLRDNORM;
2041 if (tty->packet && tty->link->ctrl_status)
2042 mask |= POLLPRI | POLLIN | POLLRDNORM;
2043 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
2044 mask |= POLLHUP;
2045 if (tty_hung_up_p(file))
2046 mask |= POLLHUP;
2047 if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) {
2048 if (MIN_CHAR(tty) && !TIME_CHAR(tty))
2049 tty->minimum_to_wake = MIN_CHAR(tty);
2050 else
2051 tty->minimum_to_wake = 1;
2052 }
Alan Coxf34d7a52008-04-30 00:54:13 -07002053 if (tty->ops->write && !tty_is_writelocked(tty) &&
2054 tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
2055 tty_write_room(tty) > 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002056 mask |= POLLOUT | POLLWRNORM;
2057 return mask;
2058}
2059
Alan Cox47afa7a2008-10-13 10:44:17 +01002060static unsigned long inq_canon(struct tty_struct *tty)
2061{
2062 int nr, head, tail;
2063
Alan Cox17b82062008-10-13 10:45:06 +01002064 if (!tty->canon_data)
Alan Cox47afa7a2008-10-13 10:44:17 +01002065 return 0;
2066 head = tty->canon_head;
2067 tail = tty->read_tail;
2068 nr = (head - tail) & (N_TTY_BUF_SIZE-1);
2069 /* Skip EOF-chars.. */
2070 while (head != tail) {
2071 if (test_bit(tail, tty->read_flags) &&
2072 tty->read_buf[tail] == __DISABLED_CHAR)
2073 nr--;
2074 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
2075 }
2076 return nr;
2077}
2078
2079static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
2080 unsigned int cmd, unsigned long arg)
2081{
2082 int retval;
2083
2084 switch (cmd) {
2085 case TIOCOUTQ:
2086 return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
2087 case TIOCINQ:
Alan Cox17b82062008-10-13 10:45:06 +01002088 /* FIXME: Locking */
Alan Cox47afa7a2008-10-13 10:44:17 +01002089 retval = tty->read_cnt;
2090 if (L_ICANON(tty))
2091 retval = inq_canon(tty);
2092 return put_user(retval, (unsigned int __user *) arg);
2093 default:
2094 return n_tty_ioctl_helper(tty, file, cmd, arg);
2095 }
2096}
2097
Alan Coxa352def2008-07-16 21:53:12 +01002098struct tty_ldisc_ops tty_ldisc_N_TTY = {
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002099 .magic = TTY_LDISC_MAGIC,
2100 .name = "n_tty",
2101 .open = n_tty_open,
2102 .close = n_tty_close,
2103 .flush_buffer = n_tty_flush_buffer,
2104 .chars_in_buffer = n_tty_chars_in_buffer,
Alan Cox11a96d12008-10-13 10:46:24 +01002105 .read = n_tty_read,
2106 .write = n_tty_write,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002107 .ioctl = n_tty_ioctl,
2108 .set_termios = n_tty_set_termios,
Alan Cox11a96d12008-10-13 10:46:24 +01002109 .poll = n_tty_poll,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002110 .receive_buf = n_tty_receive_buf,
2111 .write_wakeup = n_tty_write_wakeup
Linus Torvalds1da177e2005-04-16 15:20:36 -07002112};
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -08002113
2114/**
2115 * n_tty_inherit_ops - inherit N_TTY methods
2116 * @ops: struct tty_ldisc_ops where to save N_TTY methods
2117 *
2118 * Used by a generic struct tty_ldisc_ops to easily inherit N_TTY
2119 * methods.
2120 */
2121
2122void n_tty_inherit_ops(struct tty_ldisc_ops *ops)
2123{
2124 *ops = tty_ldisc_N_TTY;
2125 ops->owner = NULL;
2126 ops->refcount = ops->flags = 0;
2127}
2128EXPORT_SYMBOL_GPL(n_tty_inherit_ops);