blob: ee1c268f5f9d6582da5b0eeb5121ada945fcd800 [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
54/* number of characters left in xmit buffer before select has we have room */
55#define WAKEUP_CHARS 256
56
57/*
58 * This defines the low- and high-watermarks for throttling and
59 * unthrottling the TTY driver. These watermarks are used for
60 * controlling the space in the read buffer.
61 */
62#define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */
Thorsten Wißmannbbd20752011-12-08 17:47:33 +010063#define TTY_THRESHOLD_UNTHROTTLE 128
Linus Torvalds1da177e2005-04-16 15:20:36 -070064
Joe Petersona88a69c2009-01-02 13:40:53 +000065/*
66 * Special byte codes used in the echo buffer to represent operations
67 * or special handling of characters. Bytes in the echo buffer that
68 * are not part of such special blocks are treated as normal character
69 * codes.
70 */
71#define ECHO_OP_START 0xff
72#define ECHO_OP_MOVE_BACK_COL 0x80
73#define ECHO_OP_SET_CANON_COL 0x81
74#define ECHO_OP_ERASE_TAB 0x82
75
Miloslav Trmac522ed772007-07-15 23:40:56 -070076static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
77 unsigned char __user *ptr)
78{
79 tty_audit_add_data(tty, &x, 1);
80 return put_user(x, ptr);
81}
82
Linus Torvalds55db4c62011-06-04 06:33:24 +090083/**
84 * n_tty_set__room - receive space
85 * @tty: terminal
86 *
87 * Called by the driver to find out how much data it is
88 * permitted to feed to the line discipline without any being lost
89 * and thus to manage flow control. Not serialized. Answers for the
90 * "instant".
91 */
92
93static void n_tty_set_room(struct tty_struct *tty)
94{
95 /* tty->read_cnt is not read locked ? */
96 int left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
97 int old_left;
98
99 /*
100 * If we are doing input canonicalization, and there are no
101 * pending newlines, let characters through without limit, so
102 * that erase characters will be handled. Other excess
103 * characters will be beeped.
104 */
105 if (left <= 0)
106 left = tty->icanon && !tty->canon_data;
107 old_left = tty->receive_room;
108 tty->receive_room = left;
109
110 /* Did this open up the receive buffer? We may need to flip */
111 if (left && !old_left)
112 schedule_work(&tty->buf.work);
113}
114
Alan Cox33f0f882006-01-09 20:54:13 -0800115static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116{
117 if (tty->read_cnt < N_TTY_BUF_SIZE) {
118 tty->read_buf[tty->read_head] = c;
119 tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1);
120 tty->read_cnt++;
121 }
122}
123
Alan Cox17b82062008-10-13 10:45:06 +0100124/**
125 * put_tty_queue - add character to tty
126 * @c: character
127 * @tty: tty device
128 *
129 * Add a character to the tty read_buf queue. This is done under the
130 * read_lock to serialize character addition and also to protect us
131 * against parallel reads or flushes
132 */
133
Alan Cox33f0f882006-01-09 20:54:13 -0800134static void put_tty_queue(unsigned char c, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135{
136 unsigned long flags;
137 /*
138 * The problem of stomping on the buffers ends here.
139 * Why didn't anyone see this one coming? --AJK
140 */
141 spin_lock_irqsave(&tty->read_lock, flags);
142 put_tty_queue_nolock(c, tty);
143 spin_unlock_irqrestore(&tty->read_lock, flags);
144}
145
146/**
147 * check_unthrottle - allow new receive data
148 * @tty; tty device
149 *
Alan Cox17b82062008-10-13 10:45:06 +0100150 * Check whether to call the driver unthrottle functions
151 *
Ingo Molnar70522e12006-03-23 03:00:31 -0800152 * Can sleep, may be called under the atomic_read_lock mutex but
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 * this is not guaranteed.
154 */
Alan Cox4edf1822008-02-08 04:18:44 -0800155static void check_unthrottle(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156{
Alan Cox39c2e602008-04-30 00:54:18 -0700157 if (tty->count)
158 tty_unthrottle(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159}
160
161/**
162 * reset_buffer_flags - reset buffer state
163 * @tty: terminal to reset
164 *
Alan Cox4edf1822008-02-08 04:18:44 -0800165 * Reset the read buffer counters, clear the flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 * and make sure the driver is unthrottled. Called
167 * from n_tty_open() and n_tty_flush_buffer().
Alan Cox17b82062008-10-13 10:45:06 +0100168 *
169 * Locking: tty_read_lock for read fields.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000171
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172static void reset_buffer_flags(struct tty_struct *tty)
173{
174 unsigned long flags;
175
176 spin_lock_irqsave(&tty->read_lock, flags);
177 tty->read_head = tty->read_tail = tty->read_cnt = 0;
178 spin_unlock_irqrestore(&tty->read_lock, flags);
Joe Petersona88a69c2009-01-02 13:40:53 +0000179
180 mutex_lock(&tty->echo_lock);
181 tty->echo_pos = tty->echo_cnt = tty->echo_overrun = 0;
182 mutex_unlock(&tty->echo_lock);
183
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 tty->canon_head = tty->canon_data = tty->erasing = 0;
185 memset(&tty->read_flags, 0, sizeof tty->read_flags);
Linus Torvalds55db4c62011-06-04 06:33:24 +0900186 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187}
188
189/**
190 * n_tty_flush_buffer - clean input queue
191 * @tty: terminal device
192 *
193 * Flush the input buffer. Called when the line discipline is
194 * being closed, when the tty layer wants the buffer flushed (eg
195 * at hangup) or when the N_TTY line discipline internally has to
196 * clean the pending queue (for example some signals).
197 *
Alan Cox17b82062008-10-13 10:45:06 +0100198 * Locking: ctrl_lock, read_lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 */
Alan Cox4edf1822008-02-08 04:18:44 -0800200
201static void n_tty_flush_buffer(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202{
Alan Cox04f378b2008-04-30 00:53:29 -0700203 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 /* clear everything and unthrottle the driver */
205 reset_buffer_flags(tty);
Alan Cox4edf1822008-02-08 04:18:44 -0800206
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 if (!tty->link)
208 return;
209
Alan Cox04f378b2008-04-30 00:53:29 -0700210 spin_lock_irqsave(&tty->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 if (tty->link->packet) {
212 tty->ctrl_status |= TIOCPKT_FLUSHREAD;
213 wake_up_interruptible(&tty->link->read_wait);
214 }
Alan Cox04f378b2008-04-30 00:53:29 -0700215 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216}
217
218/**
219 * n_tty_chars_in_buffer - report available bytes
220 * @tty: tty device
221 *
222 * Report the number of characters buffered to be delivered to user
Alan Cox4edf1822008-02-08 04:18:44 -0800223 * at this instant in time.
Alan Cox17b82062008-10-13 10:45:06 +0100224 *
225 * Locking: read_lock
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 */
Alan Cox4edf1822008-02-08 04:18:44 -0800227
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
229{
230 unsigned long flags;
231 ssize_t n = 0;
232
233 spin_lock_irqsave(&tty->read_lock, flags);
234 if (!tty->icanon) {
235 n = tty->read_cnt;
236 } else if (tty->canon_data) {
237 n = (tty->canon_head > tty->read_tail) ?
238 tty->canon_head - tty->read_tail :
239 tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail);
240 }
241 spin_unlock_irqrestore(&tty->read_lock, flags);
242 return n;
243}
244
245/**
246 * is_utf8_continuation - utf8 multibyte check
247 * @c: byte to check
248 *
249 * Returns true if the utf8 character 'c' is a multibyte continuation
250 * character. We use this to correctly compute the on screen size
251 * of the character when printing
252 */
Alan Cox4edf1822008-02-08 04:18:44 -0800253
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254static inline int is_utf8_continuation(unsigned char c)
255{
256 return (c & 0xc0) == 0x80;
257}
258
259/**
260 * is_continuation - multibyte check
261 * @c: byte to check
262 *
263 * Returns true if the utf8 character 'c' is a multibyte continuation
264 * character and the terminal is in unicode mode.
265 */
Alan Cox4edf1822008-02-08 04:18:44 -0800266
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267static inline int is_continuation(unsigned char c, struct tty_struct *tty)
268{
269 return I_IUTF8(tty) && is_utf8_continuation(c);
270}
271
272/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000273 * do_output_char - output one character
274 * @c: character (or partial unicode symbol)
275 * @tty: terminal device
276 * @space: space available in tty driver write buffer
277 *
278 * This is a helper function that handles one output character
279 * (including special characters like TAB, CR, LF, etc.),
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600280 * doing OPOST processing and putting the results in the
281 * tty driver's write buffer.
Joe Petersona88a69c2009-01-02 13:40:53 +0000282 *
283 * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY
284 * and NLDLY. They simply aren't relevant in the world today.
285 * If you ever need them, add them here.
286 *
287 * Returns the number of bytes of buffer space used or -1 if
288 * no space left.
289 *
290 * Locking: should be called under the output_lock to protect
291 * the column state and space left in the buffer
292 */
293
294static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
295{
296 int spaces;
297
298 if (!space)
299 return -1;
Alan Cox300a6202009-01-02 13:41:04 +0000300
Joe Petersona88a69c2009-01-02 13:40:53 +0000301 switch (c) {
302 case '\n':
303 if (O_ONLRET(tty))
304 tty->column = 0;
305 if (O_ONLCR(tty)) {
306 if (space < 2)
307 return -1;
308 tty->canon_column = tty->column = 0;
Linus Torvalds37f81fa2009-09-05 12:46:07 -0700309 tty->ops->write(tty, "\r\n", 2);
Joe Petersona88a69c2009-01-02 13:40:53 +0000310 return 2;
311 }
312 tty->canon_column = tty->column;
313 break;
314 case '\r':
315 if (O_ONOCR(tty) && tty->column == 0)
316 return 0;
317 if (O_OCRNL(tty)) {
318 c = '\n';
319 if (O_ONLRET(tty))
320 tty->canon_column = tty->column = 0;
321 break;
322 }
323 tty->canon_column = tty->column = 0;
324 break;
325 case '\t':
326 spaces = 8 - (tty->column & 7);
327 if (O_TABDLY(tty) == XTABS) {
328 if (space < spaces)
329 return -1;
330 tty->column += spaces;
331 tty->ops->write(tty, " ", spaces);
332 return spaces;
333 }
334 tty->column += spaces;
335 break;
336 case '\b':
337 if (tty->column > 0)
338 tty->column--;
339 break;
340 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000341 if (!iscntrl(c)) {
342 if (O_OLCUC(tty))
343 c = toupper(c);
344 if (!is_continuation(c, tty))
345 tty->column++;
346 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000347 break;
348 }
349
350 tty_put_char(tty, c);
351 return 1;
352}
353
354/**
355 * process_output - output post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 * @c: character (or partial unicode symbol)
357 * @tty: terminal device
358 *
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600359 * Output one character with OPOST processing.
360 * Returns -1 when the output device is full and the character
361 * must be retried.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000363 * Locking: output_lock to protect column state and space left
364 * (also, this is called from n_tty_write under the
365 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 */
Alan Cox4edf1822008-02-08 04:18:44 -0800367
Joe Petersona88a69c2009-01-02 13:40:53 +0000368static int process_output(unsigned char c, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369{
Joe Petersona88a69c2009-01-02 13:40:53 +0000370 int space, retval;
371
372 mutex_lock(&tty->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373
Alan Coxf34d7a52008-04-30 00:54:13 -0700374 space = tty_write_room(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +0000375 retval = do_output_char(c, tty, space);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376
Joe Petersona88a69c2009-01-02 13:40:53 +0000377 mutex_unlock(&tty->output_lock);
378 if (retval < 0)
379 return -1;
380 else
381 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382}
383
384/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000385 * process_output_block - block post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 * @tty: terminal device
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600387 * @buf: character buffer
388 * @nr: number of bytes to output
389 *
390 * Output a block of characters with OPOST processing.
391 * Returns the number of characters output.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 *
393 * This path is used to speed up block console writes, among other
394 * things when processing blocks of output data. It handles only
395 * the simple cases normally found and helps to generate blocks of
396 * symbols for the console driver and thus improve performance.
397 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000398 * Locking: output_lock to protect column state and space left
399 * (also, this is called from n_tty_write under the
400 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 */
Alan Cox4edf1822008-02-08 04:18:44 -0800402
Joe Petersona88a69c2009-01-02 13:40:53 +0000403static ssize_t process_output_block(struct tty_struct *tty,
404 const unsigned char *buf, unsigned int nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405{
406 int space;
Thorsten Wißmannbbd20752011-12-08 17:47:33 +0100407 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 const unsigned char *cp;
409
Joe Petersona88a69c2009-01-02 13:40:53 +0000410 mutex_lock(&tty->output_lock);
411
Alan Coxf34d7a52008-04-30 00:54:13 -0700412 space = tty_write_room(tty);
Alan Cox300a6202009-01-02 13:41:04 +0000413 if (!space) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000414 mutex_unlock(&tty->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 return 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000416 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 if (nr > space)
418 nr = space;
419
420 for (i = 0, cp = buf; i < nr; i++, cp++) {
Joe Petersona59c0d62009-01-02 13:43:25 +0000421 unsigned char c = *cp;
422
423 switch (c) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 case '\n':
425 if (O_ONLRET(tty))
426 tty->column = 0;
427 if (O_ONLCR(tty))
428 goto break_out;
429 tty->canon_column = tty->column;
430 break;
431 case '\r':
432 if (O_ONOCR(tty) && tty->column == 0)
433 goto break_out;
434 if (O_OCRNL(tty))
435 goto break_out;
436 tty->canon_column = tty->column = 0;
437 break;
438 case '\t':
439 goto break_out;
440 case '\b':
441 if (tty->column > 0)
442 tty->column--;
443 break;
444 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000445 if (!iscntrl(c)) {
446 if (O_OLCUC(tty))
447 goto break_out;
448 if (!is_continuation(c, tty))
449 tty->column++;
450 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 break;
452 }
453 }
454break_out:
Alan Coxf34d7a52008-04-30 00:54:13 -0700455 i = tty->ops->write(tty, buf, i);
Joe Petersona88a69c2009-01-02 13:40:53 +0000456
457 mutex_unlock(&tty->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 return i;
459}
460
Joe Petersona88a69c2009-01-02 13:40:53 +0000461/**
462 * process_echoes - write pending echo characters
463 * @tty: terminal device
464 *
465 * Write previously buffered echo (and other ldisc-generated)
466 * characters to the tty.
467 *
468 * Characters generated by the ldisc (including echoes) need to
469 * be buffered because the driver's write buffer can fill during
470 * heavy program output. Echoing straight to the driver will
471 * often fail under these conditions, causing lost characters and
472 * resulting mismatches of ldisc state information.
473 *
474 * Since the ldisc state must represent the characters actually sent
475 * to the driver at the time of the write, operations like certain
476 * changes in column state are also saved in the buffer and executed
477 * here.
478 *
479 * A circular fifo buffer is used so that the most recent characters
480 * are prioritized. Also, when control characters are echoed with a
481 * prefixed "^", the pair is treated atomically and thus not separated.
482 *
483 * Locking: output_lock to protect column state and space left,
484 * echo_lock to protect the echo buffer
485 */
486
487static void process_echoes(struct tty_struct *tty)
488{
489 int space, nr;
490 unsigned char c;
491 unsigned char *cp, *buf_end;
492
493 if (!tty->echo_cnt)
494 return;
495
496 mutex_lock(&tty->output_lock);
497 mutex_lock(&tty->echo_lock);
498
499 space = tty_write_room(tty);
500
501 buf_end = tty->echo_buf + N_TTY_BUF_SIZE;
502 cp = tty->echo_buf + tty->echo_pos;
503 nr = tty->echo_cnt;
504 while (nr > 0) {
505 c = *cp;
506 if (c == ECHO_OP_START) {
507 unsigned char op;
508 unsigned char *opp;
509 int no_space_left = 0;
510
511 /*
512 * If the buffer byte is the start of a multi-byte
513 * operation, get the next byte, which is either the
514 * op code or a control character value.
515 */
516 opp = cp + 1;
517 if (opp == buf_end)
518 opp -= N_TTY_BUF_SIZE;
519 op = *opp;
Alan Cox300a6202009-01-02 13:41:04 +0000520
Joe Petersona88a69c2009-01-02 13:40:53 +0000521 switch (op) {
522 unsigned int num_chars, num_bs;
523
524 case ECHO_OP_ERASE_TAB:
525 if (++opp == buf_end)
526 opp -= N_TTY_BUF_SIZE;
527 num_chars = *opp;
528
529 /*
530 * Determine how many columns to go back
531 * in order to erase the tab.
532 * This depends on the number of columns
533 * used by other characters within the tab
534 * area. If this (modulo 8) count is from
535 * the start of input rather than from a
536 * previous tab, we offset by canon column.
537 * Otherwise, tab spacing is normal.
538 */
539 if (!(num_chars & 0x80))
540 num_chars += tty->canon_column;
541 num_bs = 8 - (num_chars & 7);
542
543 if (num_bs > space) {
544 no_space_left = 1;
545 break;
546 }
547 space -= num_bs;
548 while (num_bs--) {
549 tty_put_char(tty, '\b');
550 if (tty->column > 0)
551 tty->column--;
552 }
553 cp += 3;
554 nr -= 3;
555 break;
556
557 case ECHO_OP_SET_CANON_COL:
558 tty->canon_column = tty->column;
559 cp += 2;
560 nr -= 2;
561 break;
562
563 case ECHO_OP_MOVE_BACK_COL:
564 if (tty->column > 0)
565 tty->column--;
566 cp += 2;
567 nr -= 2;
568 break;
569
570 case ECHO_OP_START:
571 /* This is an escaped echo op start code */
572 if (!space) {
573 no_space_left = 1;
574 break;
575 }
576 tty_put_char(tty, ECHO_OP_START);
577 tty->column++;
578 space--;
579 cp += 2;
580 nr -= 2;
581 break;
582
583 default:
Joe Petersona88a69c2009-01-02 13:40:53 +0000584 /*
Joe Peterson62b26352009-09-09 15:03:47 -0600585 * If the op is not a special byte code,
586 * it is a ctrl char tagged to be echoed
587 * as "^X" (where X is the letter
588 * representing the control char).
589 * Note that we must ensure there is
590 * enough space for the whole ctrl pair.
591 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000592 */
Joe Peterson62b26352009-09-09 15:03:47 -0600593 if (space < 2) {
594 no_space_left = 1;
595 break;
596 }
597 tty_put_char(tty, '^');
598 tty_put_char(tty, op ^ 0100);
599 tty->column += 2;
600 space -= 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000601 cp += 2;
602 nr -= 2;
603 }
604
605 if (no_space_left)
606 break;
607 } else {
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600608 if (O_OPOST(tty) &&
609 !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
610 int retval = do_output_char(c, tty, space);
611 if (retval < 0)
612 break;
613 space -= retval;
614 } else {
615 if (!space)
616 break;
617 tty_put_char(tty, c);
618 space -= 1;
619 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000620 cp += 1;
621 nr -= 1;
622 }
623
624 /* When end of circular buffer reached, wrap around */
625 if (cp >= buf_end)
626 cp -= N_TTY_BUF_SIZE;
627 }
628
629 if (nr == 0) {
630 tty->echo_pos = 0;
631 tty->echo_cnt = 0;
632 tty->echo_overrun = 0;
633 } else {
634 int num_processed = tty->echo_cnt - nr;
635 tty->echo_pos += num_processed;
636 tty->echo_pos &= N_TTY_BUF_SIZE - 1;
637 tty->echo_cnt = nr;
638 if (num_processed > 0)
639 tty->echo_overrun = 0;
640 }
641
642 mutex_unlock(&tty->echo_lock);
643 mutex_unlock(&tty->output_lock);
644
645 if (tty->ops->flush_chars)
646 tty->ops->flush_chars(tty);
647}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648
649/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000650 * add_echo_byte - add a byte to the echo buffer
651 * @c: unicode byte to echo
652 * @tty: terminal device
653 *
654 * Add a character or operation byte to the echo buffer.
655 *
656 * Should be called under the echo lock to protect the echo buffer.
657 */
658
659static void add_echo_byte(unsigned char c, struct tty_struct *tty)
660{
661 int new_byte_pos;
662
663 if (tty->echo_cnt == N_TTY_BUF_SIZE) {
664 /* Circular buffer is already at capacity */
665 new_byte_pos = tty->echo_pos;
666
667 /*
668 * Since the buffer start position needs to be advanced,
669 * be sure to step by a whole operation byte group.
670 */
Alan Cox300a6202009-01-02 13:41:04 +0000671 if (tty->echo_buf[tty->echo_pos] == ECHO_OP_START) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000672 if (tty->echo_buf[(tty->echo_pos + 1) &
673 (N_TTY_BUF_SIZE - 1)] ==
674 ECHO_OP_ERASE_TAB) {
675 tty->echo_pos += 3;
676 tty->echo_cnt -= 2;
677 } else {
678 tty->echo_pos += 2;
679 tty->echo_cnt -= 1;
680 }
681 } else {
682 tty->echo_pos++;
683 }
684 tty->echo_pos &= N_TTY_BUF_SIZE - 1;
685
686 tty->echo_overrun = 1;
687 } else {
688 new_byte_pos = tty->echo_pos + tty->echo_cnt;
689 new_byte_pos &= N_TTY_BUF_SIZE - 1;
690 tty->echo_cnt++;
691 }
692
693 tty->echo_buf[new_byte_pos] = c;
694}
695
696/**
697 * echo_move_back_col - add operation to move back a column
698 * @tty: terminal device
699 *
700 * Add an operation to the echo buffer to move back one column.
701 *
702 * Locking: echo_lock to protect the echo buffer
703 */
704
705static void echo_move_back_col(struct tty_struct *tty)
706{
707 mutex_lock(&tty->echo_lock);
708
709 add_echo_byte(ECHO_OP_START, tty);
710 add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty);
711
712 mutex_unlock(&tty->echo_lock);
713}
714
715/**
716 * echo_set_canon_col - add operation to set the canon column
717 * @tty: terminal device
718 *
719 * Add an operation to the echo buffer to set the canon column
720 * to the current column.
721 *
722 * Locking: echo_lock to protect the echo buffer
723 */
724
725static void echo_set_canon_col(struct tty_struct *tty)
726{
727 mutex_lock(&tty->echo_lock);
728
729 add_echo_byte(ECHO_OP_START, tty);
730 add_echo_byte(ECHO_OP_SET_CANON_COL, tty);
731
732 mutex_unlock(&tty->echo_lock);
733}
734
735/**
736 * echo_erase_tab - add operation to erase a tab
737 * @num_chars: number of character columns already used
738 * @after_tab: true if num_chars starts after a previous tab
739 * @tty: terminal device
740 *
741 * Add an operation to the echo buffer to erase a tab.
742 *
743 * Called by the eraser function, which knows how many character
744 * columns have been used since either a previous tab or the start
745 * of input. This information will be used later, along with
746 * canon column (if applicable), to go back the correct number
747 * of columns.
748 *
749 * Locking: echo_lock to protect the echo buffer
750 */
751
752static void echo_erase_tab(unsigned int num_chars, int after_tab,
753 struct tty_struct *tty)
754{
755 mutex_lock(&tty->echo_lock);
756
757 add_echo_byte(ECHO_OP_START, tty);
758 add_echo_byte(ECHO_OP_ERASE_TAB, tty);
759
760 /* We only need to know this modulo 8 (tab spacing) */
761 num_chars &= 7;
762
763 /* Set the high bit as a flag if num_chars is after a previous tab */
764 if (after_tab)
765 num_chars |= 0x80;
Alan Cox300a6202009-01-02 13:41:04 +0000766
Joe Petersona88a69c2009-01-02 13:40:53 +0000767 add_echo_byte(num_chars, tty);
768
769 mutex_unlock(&tty->echo_lock);
770}
771
772/**
773 * echo_char_raw - echo a character raw
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 * @c: unicode byte to echo
775 * @tty: terminal device
776 *
Alan Cox4edf1822008-02-08 04:18:44 -0800777 * Echo user input back onto the screen. This must be called only when
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 * L_ECHO(tty) is true. Called from the driver receive_buf path.
Alan Cox17b82062008-10-13 10:45:06 +0100779 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000780 * This variant does not treat control characters specially.
781 *
782 * Locking: echo_lock to protect the echo buffer
783 */
784
785static void echo_char_raw(unsigned char c, struct tty_struct *tty)
786{
787 mutex_lock(&tty->echo_lock);
788
789 if (c == ECHO_OP_START) {
790 add_echo_byte(ECHO_OP_START, tty);
791 add_echo_byte(ECHO_OP_START, tty);
792 } else {
793 add_echo_byte(c, tty);
794 }
795
796 mutex_unlock(&tty->echo_lock);
797}
798
799/**
800 * echo_char - echo a character
801 * @c: unicode byte to echo
802 * @tty: terminal device
803 *
804 * Echo user input back onto the screen. This must be called only when
805 * L_ECHO(tty) is true. Called from the driver receive_buf path.
806 *
Joe Peterson62b26352009-09-09 15:03:47 -0600807 * This variant tags control characters to be echoed as "^X"
808 * (where X is the letter representing the control char).
Joe Petersona88a69c2009-01-02 13:40:53 +0000809 *
810 * Locking: echo_lock to protect the echo buffer
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 */
812
813static void echo_char(unsigned char c, struct tty_struct *tty)
814{
Joe Petersona88a69c2009-01-02 13:40:53 +0000815 mutex_lock(&tty->echo_lock);
816
817 if (c == ECHO_OP_START) {
818 add_echo_byte(ECHO_OP_START, tty);
819 add_echo_byte(ECHO_OP_START, tty);
820 } else {
Joe Peterson62b26352009-09-09 15:03:47 -0600821 if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t')
Joe Petersona88a69c2009-01-02 13:40:53 +0000822 add_echo_byte(ECHO_OP_START, tty);
823 add_echo_byte(c, tty);
824 }
825
826 mutex_unlock(&tty->echo_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827}
828
Alan Cox17b82062008-10-13 10:45:06 +0100829/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000830 * finish_erasing - complete erase
Alan Cox17b82062008-10-13 10:45:06 +0100831 * @tty: tty doing the erase
Alan Cox17b82062008-10-13 10:45:06 +0100832 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000833
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834static inline void finish_erasing(struct tty_struct *tty)
835{
836 if (tty->erasing) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000837 echo_char_raw('/', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 tty->erasing = 0;
839 }
840}
841
842/**
843 * eraser - handle erase function
844 * @c: character input
845 * @tty: terminal device
846 *
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200847 * Perform erase and necessary output when an erase character is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 * present in the stream from the driver layer. Handles the complexities
849 * of UTF-8 multibyte symbols.
Alan Cox17b82062008-10-13 10:45:06 +0100850 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000851 * Locking: read_lock for tty buffers
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 */
Alan Cox4edf1822008-02-08 04:18:44 -0800853
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854static void eraser(unsigned char c, struct tty_struct *tty)
855{
856 enum { ERASE, WERASE, KILL } kill_type;
857 int head, seen_alnums, cnt;
858 unsigned long flags;
859
Alan Cox17b82062008-10-13 10:45:06 +0100860 /* FIXME: locking needed ? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 if (tty->read_head == tty->canon_head) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +0000862 /* process_output('\a', tty); */ /* what do you think? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 return;
864 }
865 if (c == ERASE_CHAR(tty))
866 kill_type = ERASE;
867 else if (c == WERASE_CHAR(tty))
868 kill_type = WERASE;
869 else {
870 if (!L_ECHO(tty)) {
871 spin_lock_irqsave(&tty->read_lock, flags);
872 tty->read_cnt -= ((tty->read_head - tty->canon_head) &
873 (N_TTY_BUF_SIZE - 1));
874 tty->read_head = tty->canon_head;
875 spin_unlock_irqrestore(&tty->read_lock, flags);
876 return;
877 }
878 if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
879 spin_lock_irqsave(&tty->read_lock, flags);
880 tty->read_cnt -= ((tty->read_head - tty->canon_head) &
881 (N_TTY_BUF_SIZE - 1));
882 tty->read_head = tty->canon_head;
883 spin_unlock_irqrestore(&tty->read_lock, flags);
884 finish_erasing(tty);
885 echo_char(KILL_CHAR(tty), tty);
886 /* Add a newline if ECHOK is on and ECHOKE is off. */
887 if (L_ECHOK(tty))
Joe Petersona88a69c2009-01-02 13:40:53 +0000888 echo_char_raw('\n', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 return;
890 }
891 kill_type = KILL;
892 }
893
894 seen_alnums = 0;
Alan Cox17b82062008-10-13 10:45:06 +0100895 /* FIXME: Locking ?? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 while (tty->read_head != tty->canon_head) {
897 head = tty->read_head;
898
899 /* erase a single possibly multibyte character */
900 do {
901 head = (head - 1) & (N_TTY_BUF_SIZE-1);
902 c = tty->read_buf[head];
903 } while (is_continuation(c, tty) && head != tty->canon_head);
904
905 /* do not partially erase */
906 if (is_continuation(c, tty))
907 break;
908
909 if (kill_type == WERASE) {
910 /* Equivalent to BSD's ALTWERASE. */
911 if (isalnum(c) || c == '_')
912 seen_alnums++;
913 else if (seen_alnums)
914 break;
915 }
916 cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1);
917 spin_lock_irqsave(&tty->read_lock, flags);
918 tty->read_head = head;
919 tty->read_cnt -= cnt;
920 spin_unlock_irqrestore(&tty->read_lock, flags);
921 if (L_ECHO(tty)) {
922 if (L_ECHOPRT(tty)) {
923 if (!tty->erasing) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000924 echo_char_raw('\\', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925 tty->erasing = 1;
926 }
927 /* if cnt > 1, output a multi-byte character */
928 echo_char(c, tty);
929 while (--cnt > 0) {
930 head = (head+1) & (N_TTY_BUF_SIZE-1);
Joe Petersona88a69c2009-01-02 13:40:53 +0000931 echo_char_raw(tty->read_buf[head], tty);
932 echo_move_back_col(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 }
934 } else if (kill_type == ERASE && !L_ECHOE(tty)) {
935 echo_char(ERASE_CHAR(tty), tty);
936 } else if (c == '\t') {
Joe Petersona88a69c2009-01-02 13:40:53 +0000937 unsigned int num_chars = 0;
938 int after_tab = 0;
939 unsigned long tail = tty->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700940
Joe Petersona88a69c2009-01-02 13:40:53 +0000941 /*
942 * Count the columns used for characters
943 * since the start of input or after a
944 * previous tab.
945 * This info is used to go back the correct
946 * number of columns.
947 */
948 while (tail != tty->canon_head) {
949 tail = (tail-1) & (N_TTY_BUF_SIZE-1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950 c = tty->read_buf[tail];
Joe Petersona88a69c2009-01-02 13:40:53 +0000951 if (c == '\t') {
952 after_tab = 1;
953 break;
Alan Cox300a6202009-01-02 13:41:04 +0000954 } else if (iscntrl(c)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 if (L_ECHOCTL(tty))
Joe Petersona88a69c2009-01-02 13:40:53 +0000956 num_chars += 2;
957 } else if (!is_continuation(c, tty)) {
958 num_chars++;
959 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000961 echo_erase_tab(num_chars, after_tab, tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 } else {
963 if (iscntrl(c) && L_ECHOCTL(tty)) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000964 echo_char_raw('\b', tty);
965 echo_char_raw(' ', tty);
966 echo_char_raw('\b', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967 }
968 if (!iscntrl(c) || L_ECHOCTL(tty)) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000969 echo_char_raw('\b', tty);
970 echo_char_raw(' ', tty);
971 echo_char_raw('\b', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972 }
973 }
974 }
975 if (kill_type == ERASE)
976 break;
977 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000978 if (tty->read_head == tty->canon_head && L_ECHO(tty))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979 finish_erasing(tty);
980}
981
982/**
983 * isig - handle the ISIG optio
984 * @sig: signal
985 * @tty: terminal
986 * @flush: force flush
987 *
988 * Called when a signal is being sent due to terminal input. This
989 * may caus terminal flushing to take place according to the termios
990 * settings and character used. Called from the driver receive_buf
991 * path so serialized.
Alan Cox17b82062008-10-13 10:45:06 +0100992 *
993 * Locking: ctrl_lock, read_lock (both via flush buffer)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 */
Alan Cox4edf1822008-02-08 04:18:44 -0800995
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996static inline void isig(int sig, struct tty_struct *tty, int flush)
997{
Eric W. Biedermanab521dc2007-02-12 00:53:00 -0800998 if (tty->pgrp)
999 kill_pgrp(tty->pgrp, sig, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 if (flush || !L_NOFLSH(tty)) {
1001 n_tty_flush_buffer(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001002 tty_driver_flush_buffer(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003 }
1004}
1005
1006/**
1007 * n_tty_receive_break - handle break
1008 * @tty: terminal
1009 *
1010 * An RS232 break event has been hit in the incoming bitstream. This
1011 * can cause a variety of events depending upon the termios settings.
1012 *
1013 * Called from the receive_buf path so single threaded.
1014 */
Alan Cox4edf1822008-02-08 04:18:44 -08001015
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016static inline void n_tty_receive_break(struct tty_struct *tty)
1017{
1018 if (I_IGNBRK(tty))
1019 return;
1020 if (I_BRKINT(tty)) {
1021 isig(SIGINT, tty, 1);
1022 return;
1023 }
1024 if (I_PARMRK(tty)) {
1025 put_tty_queue('\377', tty);
1026 put_tty_queue('\0', tty);
1027 }
1028 put_tty_queue('\0', tty);
1029 wake_up_interruptible(&tty->read_wait);
1030}
1031
1032/**
1033 * n_tty_receive_overrun - handle overrun reporting
1034 * @tty: terminal
1035 *
1036 * Data arrived faster than we could process it. While the tty
1037 * driver has flagged this the bits that were missed are gone
1038 * forever.
1039 *
1040 * Called from the receive_buf path so single threaded. Does not
1041 * need locking as num_overrun and overrun_time are function
1042 * private.
1043 */
Alan Cox4edf1822008-02-08 04:18:44 -08001044
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045static inline void n_tty_receive_overrun(struct tty_struct *tty)
1046{
1047 char buf[64];
1048
1049 tty->num_overrun++;
1050 if (time_before(tty->overrun_time, jiffies - HZ) ||
1051 time_after(tty->overrun_time, jiffies)) {
1052 printk(KERN_WARNING "%s: %d input overrun(s)\n",
1053 tty_name(tty, buf),
1054 tty->num_overrun);
1055 tty->overrun_time = jiffies;
1056 tty->num_overrun = 0;
1057 }
1058}
1059
1060/**
1061 * n_tty_receive_parity_error - error notifier
1062 * @tty: terminal device
1063 * @c: character
1064 *
1065 * Process a parity error and queue the right data to indicate
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +02001066 * the error case if necessary. Locking as per n_tty_receive_buf.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001067 */
1068static inline void n_tty_receive_parity_error(struct tty_struct *tty,
1069 unsigned char c)
1070{
Alan Cox4edf1822008-02-08 04:18:44 -08001071 if (I_IGNPAR(tty))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073 if (I_PARMRK(tty)) {
1074 put_tty_queue('\377', tty);
1075 put_tty_queue('\0', tty);
1076 put_tty_queue(c, tty);
1077 } else if (I_INPCK(tty))
1078 put_tty_queue('\0', tty);
1079 else
1080 put_tty_queue(c, tty);
1081 wake_up_interruptible(&tty->read_wait);
1082}
1083
1084/**
1085 * n_tty_receive_char - perform processing
1086 * @tty: terminal device
1087 * @c: character
1088 *
1089 * Process an individual character of input received from the driver.
Alan Cox4edf1822008-02-08 04:18:44 -08001090 * This is serialized with respect to itself by the rules for the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091 * driver above.
1092 */
1093
1094static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
1095{
1096 unsigned long flags;
Joe Petersonacc71bb2009-01-02 13:43:32 +00001097 int parmrk;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098
1099 if (tty->raw) {
1100 put_tty_queue(c, tty);
1101 return;
1102 }
Alan Cox4edf1822008-02-08 04:18:44 -08001103
Linus Torvalds1da177e2005-04-16 15:20:36 -07001104 if (I_ISTRIP(tty))
1105 c &= 0x7f;
1106 if (I_IUCLC(tty) && L_IEXTEN(tty))
Alan Cox300a6202009-01-02 13:41:04 +00001107 c = tolower(c);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108
hyc@symas.com26df6d12010-06-22 10:14:49 -07001109 if (L_EXTPROC(tty)) {
1110 put_tty_queue(c, tty);
1111 return;
1112 }
1113
Joe Peterson54d2a372008-02-06 01:37:59 -08001114 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) &&
Joe Petersona88a69c2009-01-02 13:40:53 +00001115 I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) &&
1116 c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) {
Joe Peterson54d2a372008-02-06 01:37:59 -08001117 start_tty(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001118 process_echoes(tty);
1119 }
Joe Peterson54d2a372008-02-06 01:37:59 -08001120
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121 if (tty->closing) {
1122 if (I_IXON(tty)) {
Joe Petersona88a69c2009-01-02 13:40:53 +00001123 if (c == START_CHAR(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001124 start_tty(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001125 process_echoes(tty);
Alan Cox300a6202009-01-02 13:41:04 +00001126 } else if (c == STOP_CHAR(tty))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127 stop_tty(tty);
1128 }
1129 return;
1130 }
1131
1132 /*
1133 * If the previous character was LNEXT, or we know that this
1134 * character is not one of the characters that we'll have to
1135 * handle specially, do shortcut processing to speed things
1136 * up.
1137 */
1138 if (!test_bit(c, tty->process_char_map) || tty->lnext) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139 tty->lnext = 0;
Joe Petersonacc71bb2009-01-02 13:43:32 +00001140 parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
1141 if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
1142 /* beep if no space */
Joe Peterson7e94b1d2009-01-02 13:43:40 +00001143 if (L_ECHO(tty))
1144 process_output('\a', tty);
Joe Petersonacc71bb2009-01-02 13:43:32 +00001145 return;
1146 }
1147 if (L_ECHO(tty)) {
1148 finish_erasing(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 /* Record the column of first canon char. */
1150 if (tty->canon_head == tty->read_head)
Joe Petersona88a69c2009-01-02 13:40:53 +00001151 echo_set_canon_col(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 echo_char(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001153 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001154 }
Joe Petersonacc71bb2009-01-02 13:43:32 +00001155 if (parmrk)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001156 put_tty_queue(c, tty);
1157 put_tty_queue(c, tty);
1158 return;
1159 }
Alan Cox4edf1822008-02-08 04:18:44 -08001160
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161 if (I_IXON(tty)) {
1162 if (c == START_CHAR(tty)) {
1163 start_tty(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001164 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165 return;
1166 }
1167 if (c == STOP_CHAR(tty)) {
1168 stop_tty(tty);
1169 return;
1170 }
1171 }
Joe Peterson575537b32008-04-30 00:53:30 -07001172
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 if (L_ISIG(tty)) {
1174 int signal;
1175 signal = SIGINT;
1176 if (c == INTR_CHAR(tty))
1177 goto send_signal;
1178 signal = SIGQUIT;
1179 if (c == QUIT_CHAR(tty))
1180 goto send_signal;
1181 signal = SIGTSTP;
1182 if (c == SUSP_CHAR(tty)) {
1183send_signal:
Joe Petersonec5b1152008-02-06 01:37:38 -08001184 /*
Joe Petersonec5b1152008-02-06 01:37:38 -08001185 * Note that we do not use isig() here because we want
1186 * the order to be:
1187 * 1) flush, 2) echo, 3) signal
1188 */
1189 if (!L_NOFLSH(tty)) {
1190 n_tty_flush_buffer(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001191 tty_driver_flush_buffer(tty);
Joe Petersonec5b1152008-02-06 01:37:38 -08001192 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001193 if (I_IXON(tty))
1194 start_tty(tty);
1195 if (L_ECHO(tty)) {
Joe Petersonec5b1152008-02-06 01:37:38 -08001196 echo_char(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001197 process_echoes(tty);
1198 }
Joe Petersonec5b1152008-02-06 01:37:38 -08001199 if (tty->pgrp)
1200 kill_pgrp(tty->pgrp, signal, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 return;
1202 }
1203 }
Joe Peterson575537b32008-04-30 00:53:30 -07001204
1205 if (c == '\r') {
1206 if (I_IGNCR(tty))
1207 return;
1208 if (I_ICRNL(tty))
1209 c = '\n';
1210 } else if (c == '\n' && I_INLCR(tty))
1211 c = '\r';
1212
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 if (tty->icanon) {
1214 if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
1215 (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
1216 eraser(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001217 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218 return;
1219 }
1220 if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
1221 tty->lnext = 1;
1222 if (L_ECHO(tty)) {
1223 finish_erasing(tty);
1224 if (L_ECHOCTL(tty)) {
Joe Petersona88a69c2009-01-02 13:40:53 +00001225 echo_char_raw('^', tty);
1226 echo_char_raw('\b', tty);
1227 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 }
1229 }
1230 return;
1231 }
1232 if (c == REPRINT_CHAR(tty) && L_ECHO(tty) &&
1233 L_IEXTEN(tty)) {
1234 unsigned long tail = tty->canon_head;
1235
1236 finish_erasing(tty);
1237 echo_char(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001238 echo_char_raw('\n', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001239 while (tail != tty->read_head) {
1240 echo_char(tty->read_buf[tail], tty);
1241 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
1242 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001243 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244 return;
1245 }
1246 if (c == '\n') {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001247 if (tty->read_cnt >= N_TTY_BUF_SIZE) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +00001248 if (L_ECHO(tty))
1249 process_output('\a', tty);
Joe Petersonacc71bb2009-01-02 13:43:32 +00001250 return;
1251 }
1252 if (L_ECHO(tty) || L_ECHONL(tty)) {
Joe Petersona88a69c2009-01-02 13:40:53 +00001253 echo_char_raw('\n', tty);
1254 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255 }
1256 goto handle_newline;
1257 }
1258 if (c == EOF_CHAR(tty)) {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001259 if (tty->read_cnt >= N_TTY_BUF_SIZE)
1260 return;
Alan Cox4edf1822008-02-08 04:18:44 -08001261 if (tty->canon_head != tty->read_head)
1262 set_bit(TTY_PUSH, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263 c = __DISABLED_CHAR;
1264 goto handle_newline;
1265 }
1266 if ((c == EOL_CHAR(tty)) ||
1267 (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001268 parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty))
1269 ? 1 : 0;
1270 if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +00001271 if (L_ECHO(tty))
1272 process_output('\a', tty);
Joe Petersonacc71bb2009-01-02 13:43:32 +00001273 return;
1274 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 /*
1276 * XXX are EOL_CHAR and EOL2_CHAR echoed?!?
1277 */
1278 if (L_ECHO(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001279 /* Record the column of first canon char. */
1280 if (tty->canon_head == tty->read_head)
Joe Petersona88a69c2009-01-02 13:40:53 +00001281 echo_set_canon_col(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282 echo_char(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001283 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284 }
1285 /*
1286 * XXX does PARMRK doubling happen for
1287 * EOL_CHAR and EOL2_CHAR?
1288 */
Joe Petersonacc71bb2009-01-02 13:43:32 +00001289 if (parmrk)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290 put_tty_queue(c, tty);
1291
Alan Cox4edf1822008-02-08 04:18:44 -08001292handle_newline:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001293 spin_lock_irqsave(&tty->read_lock, flags);
1294 set_bit(tty->read_head, tty->read_flags);
1295 put_tty_queue_nolock(c, tty);
1296 tty->canon_head = tty->read_head;
1297 tty->canon_data++;
1298 spin_unlock_irqrestore(&tty->read_lock, flags);
1299 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
1300 if (waitqueue_active(&tty->read_wait))
1301 wake_up_interruptible(&tty->read_wait);
1302 return;
1303 }
1304 }
Alan Cox4edf1822008-02-08 04:18:44 -08001305
Joe Petersonacc71bb2009-01-02 13:43:32 +00001306 parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
1307 if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
1308 /* beep if no space */
Joe Peterson7e94b1d2009-01-02 13:43:40 +00001309 if (L_ECHO(tty))
1310 process_output('\a', tty);
Joe Petersonacc71bb2009-01-02 13:43:32 +00001311 return;
1312 }
1313 if (L_ECHO(tty)) {
1314 finish_erasing(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315 if (c == '\n')
Joe Petersona88a69c2009-01-02 13:40:53 +00001316 echo_char_raw('\n', tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317 else {
1318 /* Record the column of first canon char. */
1319 if (tty->canon_head == tty->read_head)
Joe Petersona88a69c2009-01-02 13:40:53 +00001320 echo_set_canon_col(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321 echo_char(c, tty);
1322 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001323 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001324 }
1325
Joe Petersonacc71bb2009-01-02 13:43:32 +00001326 if (parmrk)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001327 put_tty_queue(c, tty);
1328
1329 put_tty_queue(c, tty);
Alan Cox4edf1822008-02-08 04:18:44 -08001330}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332
1333/**
1334 * n_tty_write_wakeup - asynchronous I/O notifier
1335 * @tty: tty device
1336 *
1337 * Required for the ptys, serial driver etc. since processes
1338 * that attach themselves to the master and rely on ASYNC
1339 * IO must be woken up
1340 */
1341
1342static void n_tty_write_wakeup(struct tty_struct *tty)
1343{
Thomas Pfaffff8cb0f2009-01-02 13:47:13 +00001344 if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345 kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346}
1347
1348/**
1349 * n_tty_receive_buf - data receive
1350 * @tty: terminal device
1351 * @cp: buffer
1352 * @fp: flag buffer
1353 * @count: characters
1354 *
1355 * Called by the terminal driver when a block of characters has
1356 * been received. This function must be called from soft contexts
1357 * not from interrupt context. The driver is responsible for making
1358 * calls one at a time and in order (or using flush_to_ldisc)
1359 */
Alan Cox4edf1822008-02-08 04:18:44 -08001360
Linus Torvalds55db4c62011-06-04 06:33:24 +09001361static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1362 char *fp, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001363{
1364 const unsigned char *p;
1365 char *f, flags = TTY_NORMAL;
1366 int i;
1367 char buf[64];
1368 unsigned long cpuflags;
1369
1370 if (!tty->read_buf)
Linus Torvalds55db4c62011-06-04 06:33:24 +09001371 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372
1373 if (tty->real_raw) {
1374 spin_lock_irqsave(&tty->read_lock, cpuflags);
1375 i = min(N_TTY_BUF_SIZE - tty->read_cnt,
1376 N_TTY_BUF_SIZE - tty->read_head);
1377 i = min(count, i);
1378 memcpy(tty->read_buf + tty->read_head, cp, i);
1379 tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
1380 tty->read_cnt += i;
1381 cp += i;
1382 count -= i;
1383
1384 i = min(N_TTY_BUF_SIZE - tty->read_cnt,
1385 N_TTY_BUF_SIZE - tty->read_head);
1386 i = min(count, i);
1387 memcpy(tty->read_buf + tty->read_head, cp, i);
1388 tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
1389 tty->read_cnt += i;
1390 spin_unlock_irqrestore(&tty->read_lock, cpuflags);
1391 } else {
Alan Cox4edf1822008-02-08 04:18:44 -08001392 for (i = count, p = cp, f = fp; i; i--, p++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001393 if (f)
1394 flags = *f++;
1395 switch (flags) {
1396 case TTY_NORMAL:
1397 n_tty_receive_char(tty, *p);
1398 break;
1399 case TTY_BREAK:
1400 n_tty_receive_break(tty);
1401 break;
1402 case TTY_PARITY:
1403 case TTY_FRAME:
1404 n_tty_receive_parity_error(tty, *p);
1405 break;
1406 case TTY_OVERRUN:
1407 n_tty_receive_overrun(tty);
1408 break;
1409 default:
Alan Cox4edf1822008-02-08 04:18:44 -08001410 printk(KERN_ERR "%s: unknown flag %d\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001411 tty_name(tty, buf), flags);
1412 break;
1413 }
1414 }
Alan Coxf34d7a52008-04-30 00:54:13 -07001415 if (tty->ops->flush_chars)
1416 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417 }
1418
Linus Torvalds55db4c62011-06-04 06:33:24 +09001419 n_tty_set_room(tty);
1420
hyc@symas.com26df6d12010-06-22 10:14:49 -07001421 if ((!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) ||
1422 L_EXTPROC(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
1424 if (waitqueue_active(&tty->read_wait))
1425 wake_up_interruptible(&tty->read_wait);
1426 }
1427
1428 /*
1429 * Check the remaining room for the input canonicalization
1430 * mode. We don't want to throttle the driver if we're in
1431 * canonical mode and don't have a newline yet!
1432 */
Linus Torvalds55db4c62011-06-04 06:33:24 +09001433 if (tty->receive_room < TTY_THRESHOLD_THROTTLE)
Alan Cox39c2e602008-04-30 00:54:18 -07001434 tty_throttle(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435}
1436
1437int is_ignored(int sig)
1438{
1439 return (sigismember(&current->blocked, sig) ||
Alan Cox4edf1822008-02-08 04:18:44 -08001440 current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001441}
1442
1443/**
1444 * n_tty_set_termios - termios data changed
1445 * @tty: terminal
1446 * @old: previous data
1447 *
1448 * Called by the tty layer when the user changes termios flags so
1449 * that the line discipline can plan ahead. This function cannot sleep
Alan Cox4edf1822008-02-08 04:18:44 -08001450 * and is protected from re-entry by the tty layer. The user is
Linus Torvalds1da177e2005-04-16 15:20:36 -07001451 * guaranteed that this function will not be re-entered or in progress
1452 * when the ldisc is closed.
Alan Cox17b82062008-10-13 10:45:06 +01001453 *
1454 * Locking: Caller holds tty->termios_mutex
Linus Torvalds1da177e2005-04-16 15:20:36 -07001455 */
Alan Cox4edf1822008-02-08 04:18:44 -08001456
1457static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001458{
Alan Cox47afa7a2008-10-13 10:44:17 +01001459 int canon_change = 1;
1460 BUG_ON(!tty);
1461
1462 if (old)
1463 canon_change = (old->c_lflag ^ tty->termios->c_lflag) & ICANON;
1464 if (canon_change) {
1465 memset(&tty->read_flags, 0, sizeof tty->read_flags);
1466 tty->canon_head = tty->read_tail;
1467 tty->canon_data = 0;
1468 tty->erasing = 0;
1469 }
1470
1471 if (canon_change && !L_ICANON(tty) && tty->read_cnt)
1472 wake_up_interruptible(&tty->read_wait);
Alan Cox4edf1822008-02-08 04:18:44 -08001473
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474 tty->icanon = (L_ICANON(tty) != 0);
1475 if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
1476 tty->raw = 1;
1477 tty->real_raw = 1;
Linus Torvalds55db4c62011-06-04 06:33:24 +09001478 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479 return;
1480 }
1481 if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
1482 I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
1483 I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
1484 I_PARMRK(tty)) {
1485 memset(tty->process_char_map, 0, 256/8);
1486
1487 if (I_IGNCR(tty) || I_ICRNL(tty))
1488 set_bit('\r', tty->process_char_map);
1489 if (I_INLCR(tty))
1490 set_bit('\n', tty->process_char_map);
1491
1492 if (L_ICANON(tty)) {
1493 set_bit(ERASE_CHAR(tty), tty->process_char_map);
1494 set_bit(KILL_CHAR(tty), tty->process_char_map);
1495 set_bit(EOF_CHAR(tty), tty->process_char_map);
1496 set_bit('\n', tty->process_char_map);
1497 set_bit(EOL_CHAR(tty), tty->process_char_map);
1498 if (L_IEXTEN(tty)) {
1499 set_bit(WERASE_CHAR(tty),
1500 tty->process_char_map);
1501 set_bit(LNEXT_CHAR(tty),
1502 tty->process_char_map);
1503 set_bit(EOL2_CHAR(tty),
1504 tty->process_char_map);
1505 if (L_ECHO(tty))
1506 set_bit(REPRINT_CHAR(tty),
1507 tty->process_char_map);
1508 }
1509 }
1510 if (I_IXON(tty)) {
1511 set_bit(START_CHAR(tty), tty->process_char_map);
1512 set_bit(STOP_CHAR(tty), tty->process_char_map);
1513 }
1514 if (L_ISIG(tty)) {
1515 set_bit(INTR_CHAR(tty), tty->process_char_map);
1516 set_bit(QUIT_CHAR(tty), tty->process_char_map);
1517 set_bit(SUSP_CHAR(tty), tty->process_char_map);
1518 }
1519 clear_bit(__DISABLED_CHAR, tty->process_char_map);
1520 tty->raw = 0;
1521 tty->real_raw = 0;
1522 } else {
1523 tty->raw = 1;
1524 if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
1525 (I_IGNPAR(tty) || !I_INPCK(tty)) &&
1526 (tty->driver->flags & TTY_DRIVER_REAL_RAW))
1527 tty->real_raw = 1;
1528 else
1529 tty->real_raw = 0;
1530 }
Linus Torvalds55db4c62011-06-04 06:33:24 +09001531 n_tty_set_room(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001532 /* The termios change make the tty ready for I/O */
1533 wake_up_interruptible(&tty->write_wait);
1534 wake_up_interruptible(&tty->read_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001535}
1536
1537/**
1538 * n_tty_close - close the ldisc for this tty
1539 * @tty: device
1540 *
Alan Cox4edf1822008-02-08 04:18:44 -08001541 * Called from the terminal layer when this line discipline is
1542 * being shut down, either because of a close or becsuse of a
Linus Torvalds1da177e2005-04-16 15:20:36 -07001543 * discipline change. The function will not be called while other
1544 * ldisc methods are in progress.
1545 */
Alan Cox4edf1822008-02-08 04:18:44 -08001546
Linus Torvalds1da177e2005-04-16 15:20:36 -07001547static void n_tty_close(struct tty_struct *tty)
1548{
1549 n_tty_flush_buffer(tty);
1550 if (tty->read_buf) {
Alan Cox0b4068a2009-06-11 13:05:49 +01001551 kfree(tty->read_buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001552 tty->read_buf = NULL;
1553 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001554 if (tty->echo_buf) {
Alan Cox0b4068a2009-06-11 13:05:49 +01001555 kfree(tty->echo_buf);
Joe Petersona88a69c2009-01-02 13:40:53 +00001556 tty->echo_buf = NULL;
1557 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001558}
1559
1560/**
1561 * n_tty_open - open an ldisc
1562 * @tty: terminal to open
1563 *
Alan Cox4edf1822008-02-08 04:18:44 -08001564 * Called when this line discipline is being attached to the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565 * terminal device. Can sleep. Called serialized so that no
1566 * other events will occur in parallel. No further open will occur
1567 * until a close.
1568 */
1569
1570static int n_tty_open(struct tty_struct *tty)
1571{
1572 if (!tty)
1573 return -EINVAL;
1574
Joe Petersona88a69c2009-01-02 13:40:53 +00001575 /* These are ugly. Currently a malloc failure here can panic */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001576 if (!tty->read_buf) {
Alan Cox0b4068a2009-06-11 13:05:49 +01001577 tty->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001578 if (!tty->read_buf)
1579 return -ENOMEM;
1580 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001581 if (!tty->echo_buf) {
Alan Cox0b4068a2009-06-11 13:05:49 +01001582 tty->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
1583
Joe Petersona88a69c2009-01-02 13:40:53 +00001584 if (!tty->echo_buf)
1585 return -ENOMEM;
1586 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001587 reset_buffer_flags(tty);
Andrew McGregor7b292b42011-06-13 11:31:31 +12001588 tty_unthrottle(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001589 tty->column = 0;
1590 n_tty_set_termios(tty, NULL);
1591 tty->minimum_to_wake = 1;
1592 tty->closing = 0;
1593 return 0;
1594}
1595
1596static inline int input_available_p(struct tty_struct *tty, int amt)
1597{
OGAWA Hirofumie043e422009-07-29 12:15:56 -07001598 tty_flush_to_ldisc(tty);
hyc@symas.com26df6d12010-06-22 10:14:49 -07001599 if (tty->icanon && !L_EXTPROC(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001600 if (tty->canon_data)
1601 return 1;
1602 } else if (tty->read_cnt >= (amt ? amt : 1))
1603 return 1;
1604
1605 return 0;
1606}
1607
1608/**
Thorsten Wißmannbbd20752011-12-08 17:47:33 +01001609 * copy_from_read_buf - copy read data directly
Linus Torvalds1da177e2005-04-16 15:20:36 -07001610 * @tty: terminal device
1611 * @b: user data
1612 * @nr: size of data
1613 *
Alan Cox11a96d12008-10-13 10:46:24 +01001614 * Helper function to speed up n_tty_read. It is only called when
Linus Torvalds1da177e2005-04-16 15:20:36 -07001615 * ICANON is off; it copies characters straight from the tty queue to
1616 * user space directly. It can be profitably called twice; once to
1617 * drain the space from the tail pointer to the (physical) end of the
1618 * buffer, and once to drain the space from the (physical) beginning of
1619 * the buffer to head pointer.
1620 *
Paul Fulghum817d6d32006-06-28 04:26:47 -07001621 * Called under the tty->atomic_read_lock sem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001622 *
1623 */
Alan Cox4edf1822008-02-08 04:18:44 -08001624
Alan Cox33f0f882006-01-09 20:54:13 -08001625static int copy_from_read_buf(struct tty_struct *tty,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001626 unsigned char __user **b,
1627 size_t *nr)
1628
1629{
1630 int retval;
1631 size_t n;
1632 unsigned long flags;
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02001633 bool is_eof;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001634
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;
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02001643 is_eof = n == 1 &&
1644 tty->read_buf[tty->read_tail] == EOF_CHAR(tty);
Miloslav Trmac522ed772007-07-15 23:40:56 -07001645 tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001646 spin_lock_irqsave(&tty->read_lock, flags);
1647 tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1);
1648 tty->read_cnt -= n;
hyc@symas.com26df6d12010-06-22 10:14:49 -07001649 /* Turn single EOF into zero-length read */
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02001650 if (L_EXTPROC(tty) && tty->icanon && is_eof && !tty->read_cnt)
1651 n = 0;
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))
Thorsten Wißmannbbd20752011-12-08 17:47:33 +01001912 goto do_it_again;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001913
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);