blob: efbfe9612658bc5cd32b0e36c77e8651a3363746 [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
51#include <asm/uaccess.h>
52#include <asm/system.h>
53
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 */
63#define TTY_THRESHOLD_UNTHROTTLE 128
64
65static inline unsigned char *alloc_buf(void)
66{
Al Virob4e3ca12005-10-21 03:22:34 -040067 gfp_t prio = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070068
69 if (PAGE_SIZE != N_TTY_BUF_SIZE)
70 return kmalloc(N_TTY_BUF_SIZE, prio);
71 else
72 return (unsigned char *)__get_free_page(prio);
73}
74
75static inline void free_buf(unsigned char *buf)
76{
77 if (PAGE_SIZE != N_TTY_BUF_SIZE)
78 kfree(buf);
79 else
80 free_page((unsigned long) buf);
81}
82
Miloslav Trmac522ed772007-07-15 23:40:56 -070083static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
84 unsigned char __user *ptr)
85{
86 tty_audit_add_data(tty, &x, 1);
87 return put_user(x, ptr);
88}
89
Alan Cox33f0f882006-01-09 20:54:13 -080090/**
91 * n_tty_set__room - receive space
92 * @tty: terminal
93 *
94 * Called by the driver to find out how much data it is
95 * permitted to feed to the line discipline without any being lost
96 * and thus to manage flow control. Not serialized. Answers for the
97 * "instant".
98 */
99
100static void n_tty_set_room(struct tty_struct *tty)
101{
Alan Cox17b82062008-10-13 10:45:06 +0100102 /* tty->read_cnt is not read locked ? */
Alan Cox33f0f882006-01-09 20:54:13 -0800103 int left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
104
105 /*
106 * If we are doing input canonicalization, and there are no
107 * pending newlines, let characters through without limit, so
108 * that erase characters will be handled. Other excess
109 * characters will be beeped.
110 */
111 if (left <= 0)
112 left = tty->icanon && !tty->canon_data;
113 tty->receive_room = left;
114}
115
116static 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 */
172static 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);
179 tty->canon_head = tty->canon_data = tty->erasing = 0;
180 memset(&tty->read_flags, 0, sizeof tty->read_flags);
Alan Cox33f0f882006-01-09 20:54:13 -0800181 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 check_unthrottle(tty);
183}
184
185/**
186 * n_tty_flush_buffer - clean input queue
187 * @tty: terminal device
188 *
189 * Flush the input buffer. Called when the line discipline is
190 * being closed, when the tty layer wants the buffer flushed (eg
191 * at hangup) or when the N_TTY line discipline internally has to
192 * clean the pending queue (for example some signals).
193 *
Alan Cox17b82062008-10-13 10:45:06 +0100194 * Locking: ctrl_lock, read_lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 */
Alan Cox4edf1822008-02-08 04:18:44 -0800196
197static void n_tty_flush_buffer(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198{
Alan Cox04f378b2008-04-30 00:53:29 -0700199 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 /* clear everything and unthrottle the driver */
201 reset_buffer_flags(tty);
Alan Cox4edf1822008-02-08 04:18:44 -0800202
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 if (!tty->link)
204 return;
205
Alan Cox04f378b2008-04-30 00:53:29 -0700206 spin_lock_irqsave(&tty->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 if (tty->link->packet) {
208 tty->ctrl_status |= TIOCPKT_FLUSHREAD;
209 wake_up_interruptible(&tty->link->read_wait);
210 }
Alan Cox04f378b2008-04-30 00:53:29 -0700211 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212}
213
214/**
215 * n_tty_chars_in_buffer - report available bytes
216 * @tty: tty device
217 *
218 * Report the number of characters buffered to be delivered to user
Alan Cox4edf1822008-02-08 04:18:44 -0800219 * at this instant in time.
Alan Cox17b82062008-10-13 10:45:06 +0100220 *
221 * Locking: read_lock
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 */
Alan Cox4edf1822008-02-08 04:18:44 -0800223
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
225{
226 unsigned long flags;
227 ssize_t n = 0;
228
229 spin_lock_irqsave(&tty->read_lock, flags);
230 if (!tty->icanon) {
231 n = tty->read_cnt;
232 } else if (tty->canon_data) {
233 n = (tty->canon_head > tty->read_tail) ?
234 tty->canon_head - tty->read_tail :
235 tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail);
236 }
237 spin_unlock_irqrestore(&tty->read_lock, flags);
238 return n;
239}
240
241/**
242 * is_utf8_continuation - utf8 multibyte check
243 * @c: byte to check
244 *
245 * Returns true if the utf8 character 'c' is a multibyte continuation
246 * character. We use this to correctly compute the on screen size
247 * of the character when printing
248 */
Alan Cox4edf1822008-02-08 04:18:44 -0800249
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250static inline int is_utf8_continuation(unsigned char c)
251{
252 return (c & 0xc0) == 0x80;
253}
254
255/**
256 * is_continuation - multibyte check
257 * @c: byte to check
258 *
259 * Returns true if the utf8 character 'c' is a multibyte continuation
260 * character and the terminal is in unicode mode.
261 */
Alan Cox4edf1822008-02-08 04:18:44 -0800262
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263static inline int is_continuation(unsigned char c, struct tty_struct *tty)
264{
265 return I_IUTF8(tty) && is_utf8_continuation(c);
266}
267
268/**
269 * opost - output post processor
270 * @c: character (or partial unicode symbol)
271 * @tty: terminal device
272 *
273 * Perform OPOST processing. Returns -1 when the output device is
274 * full and the character must be retried. Note that Linux currently
275 * ignores TABDLY, CRDLY, VTDLY, FFDLY and NLDLY. They simply aren't
276 * relevant in the world today. If you ever need them, add them here.
277 *
278 * Called from both the receive and transmit sides and can be called
Alan Cox04f378b2008-04-30 00:53:29 -0700279 * re-entrantly. Relies on lock_kernel() for tty->column state.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 */
Alan Cox4edf1822008-02-08 04:18:44 -0800281
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282static int opost(unsigned char c, struct tty_struct *tty)
283{
284 int space, spaces;
285
Alan Coxf34d7a52008-04-30 00:54:13 -0700286 space = tty_write_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 if (!space)
288 return -1;
289
Alan Cox04f378b2008-04-30 00:53:29 -0700290 lock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 if (O_OPOST(tty)) {
292 switch (c) {
293 case '\n':
294 if (O_ONLRET(tty))
295 tty->column = 0;
296 if (O_ONLCR(tty)) {
Ingo Molnar487ad7e2008-05-14 17:11:46 +0200297 if (space < 2) {
298 unlock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 return -1;
Ingo Molnar487ad7e2008-05-14 17:11:46 +0200300 }
Alan Coxf34d7a52008-04-30 00:54:13 -0700301 tty_put_char(tty, '\r');
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 tty->column = 0;
303 }
304 tty->canon_column = tty->column;
305 break;
306 case '\r':
Ingo Molnar487ad7e2008-05-14 17:11:46 +0200307 if (O_ONOCR(tty) && tty->column == 0) {
308 unlock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 return 0;
Ingo Molnar487ad7e2008-05-14 17:11:46 +0200310 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 if (O_OCRNL(tty)) {
312 c = '\n';
313 if (O_ONLRET(tty))
314 tty->canon_column = tty->column = 0;
315 break;
316 }
317 tty->canon_column = tty->column = 0;
318 break;
319 case '\t':
320 spaces = 8 - (tty->column & 7);
321 if (O_TABDLY(tty) == XTABS) {
Ingo Molnar487ad7e2008-05-14 17:11:46 +0200322 if (space < spaces) {
323 unlock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 return -1;
Ingo Molnar487ad7e2008-05-14 17:11:46 +0200325 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 tty->column += spaces;
Alan Coxf34d7a52008-04-30 00:54:13 -0700327 tty->ops->write(tty, " ", spaces);
Ingo Molnar487ad7e2008-05-14 17:11:46 +0200328 unlock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 return 0;
330 }
331 tty->column += spaces;
332 break;
333 case '\b':
334 if (tty->column > 0)
335 tty->column--;
336 break;
337 default:
338 if (O_OLCUC(tty))
339 c = toupper(c);
340 if (!iscntrl(c) && !is_continuation(c, tty))
341 tty->column++;
342 break;
343 }
344 }
Alan Coxf34d7a52008-04-30 00:54:13 -0700345 tty_put_char(tty, c);
Alan Cox04f378b2008-04-30 00:53:29 -0700346 unlock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 return 0;
348}
349
350/**
351 * opost_block - block postprocess
352 * @tty: terminal device
353 * @inbuf: user buffer
354 * @nr: number of bytes
355 *
356 * This path is used to speed up block console writes, among other
357 * things when processing blocks of output data. It handles only
358 * the simple cases normally found and helps to generate blocks of
359 * symbols for the console driver and thus improve performance.
360 *
Alan Cox11a96d12008-10-13 10:46:24 +0100361 * Called from n_tty_write under the tty layer write lock. Relies
Alan Cox04f378b2008-04-30 00:53:29 -0700362 * on lock_kernel for the tty->column state.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 */
Alan Cox4edf1822008-02-08 04:18:44 -0800364
365static ssize_t opost_block(struct tty_struct *tty,
366 const unsigned char *buf, unsigned int nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367{
368 int space;
369 int i;
370 const unsigned char *cp;
371
Alan Coxf34d7a52008-04-30 00:54:13 -0700372 space = tty_write_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 if (!space)
374 return 0;
375 if (nr > space)
376 nr = space;
377
Alan Cox04f378b2008-04-30 00:53:29 -0700378 lock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 for (i = 0, cp = buf; i < nr; i++, cp++) {
380 switch (*cp) {
381 case '\n':
382 if (O_ONLRET(tty))
383 tty->column = 0;
384 if (O_ONLCR(tty))
385 goto break_out;
386 tty->canon_column = tty->column;
387 break;
388 case '\r':
389 if (O_ONOCR(tty) && tty->column == 0)
390 goto break_out;
391 if (O_OCRNL(tty))
392 goto break_out;
393 tty->canon_column = tty->column = 0;
394 break;
395 case '\t':
396 goto break_out;
397 case '\b':
398 if (tty->column > 0)
399 tty->column--;
400 break;
401 default:
402 if (O_OLCUC(tty))
403 goto break_out;
404 if (!iscntrl(*cp))
405 tty->column++;
406 break;
407 }
408 }
409break_out:
Alan Coxf34d7a52008-04-30 00:54:13 -0700410 if (tty->ops->flush_chars)
411 tty->ops->flush_chars(tty);
412 i = tty->ops->write(tty, buf, i);
Alan Cox04f378b2008-04-30 00:53:29 -0700413 unlock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 return i;
415}
416
417
418/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 * echo_char - echo characters
420 * @c: unicode byte to echo
421 * @tty: terminal device
422 *
Alan Cox4edf1822008-02-08 04:18:44 -0800423 * Echo user input back onto the screen. This must be called only when
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 * L_ECHO(tty) is true. Called from the driver receive_buf path.
Alan Cox17b82062008-10-13 10:45:06 +0100425 *
426 * Relies on BKL for tty column locking
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 */
428
429static void echo_char(unsigned char c, struct tty_struct *tty)
430{
431 if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') {
Alan Coxf34d7a52008-04-30 00:54:13 -0700432 tty_put_char(tty, '^');
433 tty_put_char(tty, c ^ 0100);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 tty->column += 2;
435 } else
436 opost(c, tty);
437}
438
Alan Cox17b82062008-10-13 10:45:06 +0100439/**
440 * finsh_erasing - complete erase
441 * @tty: tty doing the erase
442 *
443 * Relies on BKL for tty column locking
444 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445static inline void finish_erasing(struct tty_struct *tty)
446{
447 if (tty->erasing) {
Alan Coxf34d7a52008-04-30 00:54:13 -0700448 tty_put_char(tty, '/');
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 tty->column++;
450 tty->erasing = 0;
451 }
452}
453
454/**
455 * eraser - handle erase function
456 * @c: character input
457 * @tty: terminal device
458 *
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200459 * Perform erase and necessary output when an erase character is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460 * present in the stream from the driver layer. Handles the complexities
461 * of UTF-8 multibyte symbols.
Alan Cox17b82062008-10-13 10:45:06 +0100462 *
463 * Locking: read_lock for tty buffers, BKL for column/erasing state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 */
Alan Cox4edf1822008-02-08 04:18:44 -0800465
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466static void eraser(unsigned char c, struct tty_struct *tty)
467{
468 enum { ERASE, WERASE, KILL } kill_type;
469 int head, seen_alnums, cnt;
470 unsigned long flags;
471
Alan Cox17b82062008-10-13 10:45:06 +0100472 /* FIXME: locking needed ? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 if (tty->read_head == tty->canon_head) {
474 /* opost('\a', tty); */ /* what do you think? */
475 return;
476 }
477 if (c == ERASE_CHAR(tty))
478 kill_type = ERASE;
479 else if (c == WERASE_CHAR(tty))
480 kill_type = WERASE;
481 else {
482 if (!L_ECHO(tty)) {
483 spin_lock_irqsave(&tty->read_lock, flags);
484 tty->read_cnt -= ((tty->read_head - tty->canon_head) &
485 (N_TTY_BUF_SIZE - 1));
486 tty->read_head = tty->canon_head;
487 spin_unlock_irqrestore(&tty->read_lock, flags);
488 return;
489 }
490 if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
491 spin_lock_irqsave(&tty->read_lock, flags);
492 tty->read_cnt -= ((tty->read_head - tty->canon_head) &
493 (N_TTY_BUF_SIZE - 1));
494 tty->read_head = tty->canon_head;
495 spin_unlock_irqrestore(&tty->read_lock, flags);
496 finish_erasing(tty);
497 echo_char(KILL_CHAR(tty), tty);
498 /* Add a newline if ECHOK is on and ECHOKE is off. */
499 if (L_ECHOK(tty))
500 opost('\n', tty);
501 return;
502 }
503 kill_type = KILL;
504 }
505
506 seen_alnums = 0;
Alan Cox17b82062008-10-13 10:45:06 +0100507 /* FIXME: Locking ?? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 while (tty->read_head != tty->canon_head) {
509 head = tty->read_head;
510
511 /* erase a single possibly multibyte character */
512 do {
513 head = (head - 1) & (N_TTY_BUF_SIZE-1);
514 c = tty->read_buf[head];
515 } while (is_continuation(c, tty) && head != tty->canon_head);
516
517 /* do not partially erase */
518 if (is_continuation(c, tty))
519 break;
520
521 if (kill_type == WERASE) {
522 /* Equivalent to BSD's ALTWERASE. */
523 if (isalnum(c) || c == '_')
524 seen_alnums++;
525 else if (seen_alnums)
526 break;
527 }
528 cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1);
529 spin_lock_irqsave(&tty->read_lock, flags);
530 tty->read_head = head;
531 tty->read_cnt -= cnt;
532 spin_unlock_irqrestore(&tty->read_lock, flags);
533 if (L_ECHO(tty)) {
534 if (L_ECHOPRT(tty)) {
535 if (!tty->erasing) {
Alan Coxf34d7a52008-04-30 00:54:13 -0700536 tty_put_char(tty, '\\');
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 tty->column++;
538 tty->erasing = 1;
539 }
540 /* if cnt > 1, output a multi-byte character */
541 echo_char(c, tty);
542 while (--cnt > 0) {
543 head = (head+1) & (N_TTY_BUF_SIZE-1);
Alan Coxf34d7a52008-04-30 00:54:13 -0700544 tty_put_char(tty, tty->read_buf[head]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 }
546 } else if (kill_type == ERASE && !L_ECHOE(tty)) {
547 echo_char(ERASE_CHAR(tty), tty);
548 } else if (c == '\t') {
549 unsigned int col = tty->canon_column;
550 unsigned long tail = tty->canon_head;
551
552 /* Find the column of the last char. */
553 while (tail != tty->read_head) {
554 c = tty->read_buf[tail];
555 if (c == '\t')
556 col = (col | 7) + 1;
557 else if (iscntrl(c)) {
558 if (L_ECHOCTL(tty))
559 col += 2;
560 } else if (!is_continuation(c, tty))
561 col++;
562 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
563 }
564
565 /* should never happen */
566 if (tty->column > 0x80000000)
Alan Cox4edf1822008-02-08 04:18:44 -0800567 tty->column = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568
569 /* Now backup to that column. */
570 while (tty->column > col) {
571 /* Can't use opost here. */
Alan Coxf34d7a52008-04-30 00:54:13 -0700572 tty_put_char(tty, '\b');
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 if (tty->column > 0)
574 tty->column--;
575 }
576 } else {
577 if (iscntrl(c) && L_ECHOCTL(tty)) {
Alan Coxf34d7a52008-04-30 00:54:13 -0700578 tty_put_char(tty, '\b');
579 tty_put_char(tty, ' ');
580 tty_put_char(tty, '\b');
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 if (tty->column > 0)
582 tty->column--;
583 }
584 if (!iscntrl(c) || L_ECHOCTL(tty)) {
Alan Coxf34d7a52008-04-30 00:54:13 -0700585 tty_put_char(tty, '\b');
586 tty_put_char(tty, ' ');
587 tty_put_char(tty, '\b');
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 if (tty->column > 0)
589 tty->column--;
590 }
591 }
592 }
593 if (kill_type == ERASE)
594 break;
595 }
596 if (tty->read_head == tty->canon_head)
597 finish_erasing(tty);
598}
599
600/**
601 * isig - handle the ISIG optio
602 * @sig: signal
603 * @tty: terminal
604 * @flush: force flush
605 *
606 * Called when a signal is being sent due to terminal input. This
607 * may caus terminal flushing to take place according to the termios
608 * settings and character used. Called from the driver receive_buf
609 * path so serialized.
Alan Cox17b82062008-10-13 10:45:06 +0100610 *
611 * Locking: ctrl_lock, read_lock (both via flush buffer)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 */
Alan Cox4edf1822008-02-08 04:18:44 -0800613
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614static inline void isig(int sig, struct tty_struct *tty, int flush)
615{
Eric W. Biedermanab521dc2007-02-12 00:53:00 -0800616 if (tty->pgrp)
617 kill_pgrp(tty->pgrp, sig, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 if (flush || !L_NOFLSH(tty)) {
619 n_tty_flush_buffer(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -0700620 tty_driver_flush_buffer(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621 }
622}
623
624/**
625 * n_tty_receive_break - handle break
626 * @tty: terminal
627 *
628 * An RS232 break event has been hit in the incoming bitstream. This
629 * can cause a variety of events depending upon the termios settings.
630 *
631 * Called from the receive_buf path so single threaded.
632 */
Alan Cox4edf1822008-02-08 04:18:44 -0800633
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634static inline void n_tty_receive_break(struct tty_struct *tty)
635{
636 if (I_IGNBRK(tty))
637 return;
638 if (I_BRKINT(tty)) {
639 isig(SIGINT, tty, 1);
640 return;
641 }
642 if (I_PARMRK(tty)) {
643 put_tty_queue('\377', tty);
644 put_tty_queue('\0', tty);
645 }
646 put_tty_queue('\0', tty);
647 wake_up_interruptible(&tty->read_wait);
648}
649
650/**
651 * n_tty_receive_overrun - handle overrun reporting
652 * @tty: terminal
653 *
654 * Data arrived faster than we could process it. While the tty
655 * driver has flagged this the bits that were missed are gone
656 * forever.
657 *
658 * Called from the receive_buf path so single threaded. Does not
659 * need locking as num_overrun and overrun_time are function
660 * private.
661 */
Alan Cox4edf1822008-02-08 04:18:44 -0800662
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663static inline void n_tty_receive_overrun(struct tty_struct *tty)
664{
665 char buf[64];
666
667 tty->num_overrun++;
668 if (time_before(tty->overrun_time, jiffies - HZ) ||
669 time_after(tty->overrun_time, jiffies)) {
670 printk(KERN_WARNING "%s: %d input overrun(s)\n",
671 tty_name(tty, buf),
672 tty->num_overrun);
673 tty->overrun_time = jiffies;
674 tty->num_overrun = 0;
675 }
676}
677
678/**
679 * n_tty_receive_parity_error - error notifier
680 * @tty: terminal device
681 * @c: character
682 *
683 * Process a parity error and queue the right data to indicate
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200684 * the error case if necessary. Locking as per n_tty_receive_buf.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 */
686static inline void n_tty_receive_parity_error(struct tty_struct *tty,
687 unsigned char c)
688{
Alan Cox4edf1822008-02-08 04:18:44 -0800689 if (I_IGNPAR(tty))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 if (I_PARMRK(tty)) {
692 put_tty_queue('\377', tty);
693 put_tty_queue('\0', tty);
694 put_tty_queue(c, tty);
695 } else if (I_INPCK(tty))
696 put_tty_queue('\0', tty);
697 else
698 put_tty_queue(c, tty);
699 wake_up_interruptible(&tty->read_wait);
700}
701
702/**
703 * n_tty_receive_char - perform processing
704 * @tty: terminal device
705 * @c: character
706 *
707 * Process an individual character of input received from the driver.
Alan Cox4edf1822008-02-08 04:18:44 -0800708 * This is serialized with respect to itself by the rules for the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 * driver above.
710 */
711
712static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
713{
714 unsigned long flags;
715
716 if (tty->raw) {
717 put_tty_queue(c, tty);
718 return;
719 }
Alan Cox4edf1822008-02-08 04:18:44 -0800720
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721 if (I_ISTRIP(tty))
722 c &= 0x7f;
723 if (I_IUCLC(tty) && L_IEXTEN(tty))
724 c=tolower(c);
725
Joe Peterson54d2a372008-02-06 01:37:59 -0800726 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) &&
727 ((I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty)) ||
Joe Peterson575537b2008-04-30 00:53:30 -0700728 c == INTR_CHAR(tty) || c == QUIT_CHAR(tty) || c == SUSP_CHAR(tty)))
Joe Peterson54d2a372008-02-06 01:37:59 -0800729 start_tty(tty);
730
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 if (tty->closing) {
732 if (I_IXON(tty)) {
733 if (c == START_CHAR(tty))
734 start_tty(tty);
735 else if (c == STOP_CHAR(tty))
736 stop_tty(tty);
737 }
738 return;
739 }
740
741 /*
742 * If the previous character was LNEXT, or we know that this
743 * character is not one of the characters that we'll have to
744 * handle specially, do shortcut processing to speed things
745 * up.
746 */
747 if (!test_bit(c, tty->process_char_map) || tty->lnext) {
748 finish_erasing(tty);
749 tty->lnext = 0;
750 if (L_ECHO(tty)) {
751 if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
Alan Coxf34d7a52008-04-30 00:54:13 -0700752 tty_put_char(tty, '\a'); /* beep if no space */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 return;
754 }
755 /* Record the column of first canon char. */
756 if (tty->canon_head == tty->read_head)
757 tty->canon_column = tty->column;
758 echo_char(c, tty);
759 }
760 if (I_PARMRK(tty) && c == (unsigned char) '\377')
761 put_tty_queue(c, tty);
762 put_tty_queue(c, tty);
763 return;
764 }
Alan Cox4edf1822008-02-08 04:18:44 -0800765
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 if (I_IXON(tty)) {
767 if (c == START_CHAR(tty)) {
768 start_tty(tty);
769 return;
770 }
771 if (c == STOP_CHAR(tty)) {
772 stop_tty(tty);
773 return;
774 }
775 }
Joe Peterson575537b2008-04-30 00:53:30 -0700776
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 if (L_ISIG(tty)) {
778 int signal;
779 signal = SIGINT;
780 if (c == INTR_CHAR(tty))
781 goto send_signal;
782 signal = SIGQUIT;
783 if (c == QUIT_CHAR(tty))
784 goto send_signal;
785 signal = SIGTSTP;
786 if (c == SUSP_CHAR(tty)) {
787send_signal:
Joe Petersonec5b1152008-02-06 01:37:38 -0800788 /*
789 * Echo character, and then send the signal.
790 * Note that we do not use isig() here because we want
791 * the order to be:
792 * 1) flush, 2) echo, 3) signal
793 */
794 if (!L_NOFLSH(tty)) {
795 n_tty_flush_buffer(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -0700796 tty_driver_flush_buffer(tty);
Joe Petersonec5b1152008-02-06 01:37:38 -0800797 }
798 if (L_ECHO(tty))
799 echo_char(c, tty);
800 if (tty->pgrp)
801 kill_pgrp(tty->pgrp, signal, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 return;
803 }
804 }
Joe Peterson575537b2008-04-30 00:53:30 -0700805
806 if (c == '\r') {
807 if (I_IGNCR(tty))
808 return;
809 if (I_ICRNL(tty))
810 c = '\n';
811 } else if (c == '\n' && I_INLCR(tty))
812 c = '\r';
813
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 if (tty->icanon) {
815 if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
816 (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
817 eraser(c, tty);
818 return;
819 }
820 if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
821 tty->lnext = 1;
822 if (L_ECHO(tty)) {
823 finish_erasing(tty);
824 if (L_ECHOCTL(tty)) {
Alan Coxf34d7a52008-04-30 00:54:13 -0700825 tty_put_char(tty, '^');
826 tty_put_char(tty, '\b');
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 }
828 }
829 return;
830 }
831 if (c == REPRINT_CHAR(tty) && L_ECHO(tty) &&
832 L_IEXTEN(tty)) {
833 unsigned long tail = tty->canon_head;
834
835 finish_erasing(tty);
836 echo_char(c, tty);
837 opost('\n', tty);
838 while (tail != tty->read_head) {
839 echo_char(tty->read_buf[tail], tty);
840 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
841 }
842 return;
843 }
844 if (c == '\n') {
845 if (L_ECHO(tty) || L_ECHONL(tty)) {
Roman Zippeld6afe272005-07-07 17:56:55 -0700846 if (tty->read_cnt >= N_TTY_BUF_SIZE-1)
Alan Coxf34d7a52008-04-30 00:54:13 -0700847 tty_put_char(tty, '\a');
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 opost('\n', tty);
849 }
850 goto handle_newline;
851 }
852 if (c == EOF_CHAR(tty)) {
Alan Cox4edf1822008-02-08 04:18:44 -0800853 if (tty->canon_head != tty->read_head)
854 set_bit(TTY_PUSH, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855 c = __DISABLED_CHAR;
856 goto handle_newline;
857 }
858 if ((c == EOL_CHAR(tty)) ||
859 (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
860 /*
861 * XXX are EOL_CHAR and EOL2_CHAR echoed?!?
862 */
863 if (L_ECHO(tty)) {
Roman Zippeld6afe272005-07-07 17:56:55 -0700864 if (tty->read_cnt >= N_TTY_BUF_SIZE-1)
Alan Coxf34d7a52008-04-30 00:54:13 -0700865 tty_put_char(tty, '\a');
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866 /* Record the column of first canon char. */
867 if (tty->canon_head == tty->read_head)
868 tty->canon_column = tty->column;
869 echo_char(c, tty);
870 }
871 /*
872 * XXX does PARMRK doubling happen for
873 * EOL_CHAR and EOL2_CHAR?
874 */
875 if (I_PARMRK(tty) && c == (unsigned char) '\377')
876 put_tty_queue(c, tty);
877
Alan Cox4edf1822008-02-08 04:18:44 -0800878handle_newline:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 spin_lock_irqsave(&tty->read_lock, flags);
880 set_bit(tty->read_head, tty->read_flags);
881 put_tty_queue_nolock(c, tty);
882 tty->canon_head = tty->read_head;
883 tty->canon_data++;
884 spin_unlock_irqrestore(&tty->read_lock, flags);
885 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
886 if (waitqueue_active(&tty->read_wait))
887 wake_up_interruptible(&tty->read_wait);
888 return;
889 }
890 }
Alan Cox4edf1822008-02-08 04:18:44 -0800891
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 finish_erasing(tty);
893 if (L_ECHO(tty)) {
894 if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
Alan Coxf34d7a52008-04-30 00:54:13 -0700895 tty_put_char(tty, '\a'); /* beep if no space */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 return;
897 }
898 if (c == '\n')
899 opost('\n', tty);
900 else {
901 /* Record the column of first canon char. */
902 if (tty->canon_head == tty->read_head)
903 tty->canon_column = tty->column;
904 echo_char(c, tty);
905 }
906 }
907
908 if (I_PARMRK(tty) && c == (unsigned char) '\377')
909 put_tty_queue(c, tty);
910
911 put_tty_queue(c, tty);
Alan Cox4edf1822008-02-08 04:18:44 -0800912}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914
915/**
916 * n_tty_write_wakeup - asynchronous I/O notifier
917 * @tty: tty device
918 *
919 * Required for the ptys, serial driver etc. since processes
920 * that attach themselves to the master and rely on ASYNC
921 * IO must be woken up
922 */
923
924static void n_tty_write_wakeup(struct tty_struct *tty)
925{
Alan Cox4edf1822008-02-08 04:18:44 -0800926 if (tty->fasync) {
927 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700928 kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
929 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930}
931
932/**
933 * n_tty_receive_buf - data receive
934 * @tty: terminal device
935 * @cp: buffer
936 * @fp: flag buffer
937 * @count: characters
938 *
939 * Called by the terminal driver when a block of characters has
940 * been received. This function must be called from soft contexts
941 * not from interrupt context. The driver is responsible for making
942 * calls one at a time and in order (or using flush_to_ldisc)
943 */
Alan Cox4edf1822008-02-08 04:18:44 -0800944
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
946 char *fp, int count)
947{
948 const unsigned char *p;
949 char *f, flags = TTY_NORMAL;
950 int i;
951 char buf[64];
952 unsigned long cpuflags;
953
954 if (!tty->read_buf)
955 return;
956
957 if (tty->real_raw) {
958 spin_lock_irqsave(&tty->read_lock, cpuflags);
959 i = min(N_TTY_BUF_SIZE - tty->read_cnt,
960 N_TTY_BUF_SIZE - tty->read_head);
961 i = min(count, i);
962 memcpy(tty->read_buf + tty->read_head, cp, i);
963 tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
964 tty->read_cnt += i;
965 cp += i;
966 count -= i;
967
968 i = min(N_TTY_BUF_SIZE - tty->read_cnt,
969 N_TTY_BUF_SIZE - tty->read_head);
970 i = min(count, i);
971 memcpy(tty->read_buf + tty->read_head, cp, i);
972 tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
973 tty->read_cnt += i;
974 spin_unlock_irqrestore(&tty->read_lock, cpuflags);
975 } else {
Alan Cox4edf1822008-02-08 04:18:44 -0800976 for (i = count, p = cp, f = fp; i; i--, p++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 if (f)
978 flags = *f++;
979 switch (flags) {
980 case TTY_NORMAL:
981 n_tty_receive_char(tty, *p);
982 break;
983 case TTY_BREAK:
984 n_tty_receive_break(tty);
985 break;
986 case TTY_PARITY:
987 case TTY_FRAME:
988 n_tty_receive_parity_error(tty, *p);
989 break;
990 case TTY_OVERRUN:
991 n_tty_receive_overrun(tty);
992 break;
993 default:
Alan Cox4edf1822008-02-08 04:18:44 -0800994 printk(KERN_ERR "%s: unknown flag %d\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 tty_name(tty, buf), flags);
996 break;
997 }
998 }
Alan Coxf34d7a52008-04-30 00:54:13 -0700999 if (tty->ops->flush_chars)
1000 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001 }
1002
Alan Cox33f0f882006-01-09 20:54:13 -08001003 n_tty_set_room(tty);
1004
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 if (!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) {
1006 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
1007 if (waitqueue_active(&tty->read_wait))
1008 wake_up_interruptible(&tty->read_wait);
1009 }
1010
1011 /*
1012 * Check the remaining room for the input canonicalization
1013 * mode. We don't want to throttle the driver if we're in
1014 * canonical mode and don't have a newline yet!
1015 */
Alan Cox39c2e602008-04-30 00:54:18 -07001016 if (tty->receive_room < TTY_THRESHOLD_THROTTLE)
1017 tty_throttle(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018}
1019
1020int is_ignored(int sig)
1021{
1022 return (sigismember(&current->blocked, sig) ||
Alan Cox4edf1822008-02-08 04:18:44 -08001023 current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001024}
1025
1026/**
1027 * n_tty_set_termios - termios data changed
1028 * @tty: terminal
1029 * @old: previous data
1030 *
1031 * Called by the tty layer when the user changes termios flags so
1032 * that the line discipline can plan ahead. This function cannot sleep
Alan Cox4edf1822008-02-08 04:18:44 -08001033 * and is protected from re-entry by the tty layer. The user is
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034 * guaranteed that this function will not be re-entered or in progress
1035 * when the ldisc is closed.
Alan Cox17b82062008-10-13 10:45:06 +01001036 *
1037 * Locking: Caller holds tty->termios_mutex
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038 */
Alan Cox4edf1822008-02-08 04:18:44 -08001039
1040static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041{
Alan Cox47afa7a2008-10-13 10:44:17 +01001042 int canon_change = 1;
1043 BUG_ON(!tty);
1044
1045 if (old)
1046 canon_change = (old->c_lflag ^ tty->termios->c_lflag) & ICANON;
1047 if (canon_change) {
1048 memset(&tty->read_flags, 0, sizeof tty->read_flags);
1049 tty->canon_head = tty->read_tail;
1050 tty->canon_data = 0;
1051 tty->erasing = 0;
1052 }
1053
1054 if (canon_change && !L_ICANON(tty) && tty->read_cnt)
1055 wake_up_interruptible(&tty->read_wait);
Alan Cox4edf1822008-02-08 04:18:44 -08001056
Linus Torvalds1da177e2005-04-16 15:20:36 -07001057 tty->icanon = (L_ICANON(tty) != 0);
1058 if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
1059 tty->raw = 1;
1060 tty->real_raw = 1;
Alan Cox33f0f882006-01-09 20:54:13 -08001061 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001062 return;
1063 }
1064 if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
1065 I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
1066 I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
1067 I_PARMRK(tty)) {
1068 memset(tty->process_char_map, 0, 256/8);
1069
1070 if (I_IGNCR(tty) || I_ICRNL(tty))
1071 set_bit('\r', tty->process_char_map);
1072 if (I_INLCR(tty))
1073 set_bit('\n', tty->process_char_map);
1074
1075 if (L_ICANON(tty)) {
1076 set_bit(ERASE_CHAR(tty), tty->process_char_map);
1077 set_bit(KILL_CHAR(tty), tty->process_char_map);
1078 set_bit(EOF_CHAR(tty), tty->process_char_map);
1079 set_bit('\n', tty->process_char_map);
1080 set_bit(EOL_CHAR(tty), tty->process_char_map);
1081 if (L_IEXTEN(tty)) {
1082 set_bit(WERASE_CHAR(tty),
1083 tty->process_char_map);
1084 set_bit(LNEXT_CHAR(tty),
1085 tty->process_char_map);
1086 set_bit(EOL2_CHAR(tty),
1087 tty->process_char_map);
1088 if (L_ECHO(tty))
1089 set_bit(REPRINT_CHAR(tty),
1090 tty->process_char_map);
1091 }
1092 }
1093 if (I_IXON(tty)) {
1094 set_bit(START_CHAR(tty), tty->process_char_map);
1095 set_bit(STOP_CHAR(tty), tty->process_char_map);
1096 }
1097 if (L_ISIG(tty)) {
1098 set_bit(INTR_CHAR(tty), tty->process_char_map);
1099 set_bit(QUIT_CHAR(tty), tty->process_char_map);
1100 set_bit(SUSP_CHAR(tty), tty->process_char_map);
1101 }
1102 clear_bit(__DISABLED_CHAR, tty->process_char_map);
1103 tty->raw = 0;
1104 tty->real_raw = 0;
1105 } else {
1106 tty->raw = 1;
1107 if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
1108 (I_IGNPAR(tty) || !I_INPCK(tty)) &&
1109 (tty->driver->flags & TTY_DRIVER_REAL_RAW))
1110 tty->real_raw = 1;
1111 else
1112 tty->real_raw = 0;
1113 }
Alan Cox33f0f882006-01-09 20:54:13 -08001114 n_tty_set_room(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001115 /* The termios change make the tty ready for I/O */
1116 wake_up_interruptible(&tty->write_wait);
1117 wake_up_interruptible(&tty->read_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118}
1119
1120/**
1121 * n_tty_close - close the ldisc for this tty
1122 * @tty: device
1123 *
Alan Cox4edf1822008-02-08 04:18:44 -08001124 * Called from the terminal layer when this line discipline is
1125 * being shut down, either because of a close or becsuse of a
Linus Torvalds1da177e2005-04-16 15:20:36 -07001126 * discipline change. The function will not be called while other
1127 * ldisc methods are in progress.
1128 */
Alan Cox4edf1822008-02-08 04:18:44 -08001129
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130static void n_tty_close(struct tty_struct *tty)
1131{
1132 n_tty_flush_buffer(tty);
1133 if (tty->read_buf) {
1134 free_buf(tty->read_buf);
1135 tty->read_buf = NULL;
1136 }
1137}
1138
1139/**
1140 * n_tty_open - open an ldisc
1141 * @tty: terminal to open
1142 *
Alan Cox4edf1822008-02-08 04:18:44 -08001143 * Called when this line discipline is being attached to the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144 * terminal device. Can sleep. Called serialized so that no
1145 * other events will occur in parallel. No further open will occur
1146 * until a close.
1147 */
1148
1149static int n_tty_open(struct tty_struct *tty)
1150{
1151 if (!tty)
1152 return -EINVAL;
1153
1154 /* This one is ugly. Currently a malloc failure here can panic */
1155 if (!tty->read_buf) {
1156 tty->read_buf = alloc_buf();
1157 if (!tty->read_buf)
1158 return -ENOMEM;
1159 }
1160 memset(tty->read_buf, 0, N_TTY_BUF_SIZE);
1161 reset_buffer_flags(tty);
1162 tty->column = 0;
1163 n_tty_set_termios(tty, NULL);
1164 tty->minimum_to_wake = 1;
1165 tty->closing = 0;
1166 return 0;
1167}
1168
1169static inline int input_available_p(struct tty_struct *tty, int amt)
1170{
1171 if (tty->icanon) {
1172 if (tty->canon_data)
1173 return 1;
1174 } else if (tty->read_cnt >= (amt ? amt : 1))
1175 return 1;
1176
1177 return 0;
1178}
1179
1180/**
1181 * copy_from_read_buf - copy read data directly
1182 * @tty: terminal device
1183 * @b: user data
1184 * @nr: size of data
1185 *
Alan Cox11a96d12008-10-13 10:46:24 +01001186 * Helper function to speed up n_tty_read. It is only called when
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 * ICANON is off; it copies characters straight from the tty queue to
1188 * user space directly. It can be profitably called twice; once to
1189 * drain the space from the tail pointer to the (physical) end of the
1190 * buffer, and once to drain the space from the (physical) beginning of
1191 * the buffer to head pointer.
1192 *
Paul Fulghum817d6d32006-06-28 04:26:47 -07001193 * Called under the tty->atomic_read_lock sem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 *
1195 */
Alan Cox4edf1822008-02-08 04:18:44 -08001196
Alan Cox33f0f882006-01-09 20:54:13 -08001197static int copy_from_read_buf(struct tty_struct *tty,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198 unsigned char __user **b,
1199 size_t *nr)
1200
1201{
1202 int retval;
1203 size_t n;
1204 unsigned long flags;
1205
1206 retval = 0;
1207 spin_lock_irqsave(&tty->read_lock, flags);
1208 n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail);
1209 n = min(*nr, n);
1210 spin_unlock_irqrestore(&tty->read_lock, flags);
1211 if (n) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212 retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n);
1213 n -= retval;
Miloslav Trmac522ed772007-07-15 23:40:56 -07001214 tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 spin_lock_irqsave(&tty->read_lock, flags);
1216 tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1);
1217 tty->read_cnt -= n;
1218 spin_unlock_irqrestore(&tty->read_lock, flags);
1219 *b += n;
1220 *nr -= n;
1221 }
1222 return retval;
1223}
1224
Al Virocc4191d2008-03-29 03:08:48 +00001225extern ssize_t redirected_tty_write(struct file *, const char __user *,
Alan Cox4edf1822008-02-08 04:18:44 -08001226 size_t, loff_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001227
1228/**
1229 * job_control - check job control
1230 * @tty: tty
1231 * @file: file handle
1232 *
1233 * Perform job control management checks on this file/tty descriptor
Alan Cox4edf1822008-02-08 04:18:44 -08001234 * and if appropriate send any needed signals and return a negative
Linus Torvalds1da177e2005-04-16 15:20:36 -07001235 * error code if action should be taken.
Alan Cox04f378b2008-04-30 00:53:29 -07001236 *
1237 * FIXME:
1238 * Locking: None - redirected write test is safe, testing
1239 * current->signal should possibly lock current->sighand
1240 * pgrp locking ?
Linus Torvalds1da177e2005-04-16 15:20:36 -07001241 */
Alan Cox4edf1822008-02-08 04:18:44 -08001242
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243static int job_control(struct tty_struct *tty, struct file *file)
1244{
1245 /* Job control check -- must be done at start and after
1246 every sleep (POSIX.1 7.1.1.4). */
1247 /* NOTE: not yet done after every sleep pending a thorough
1248 check of the logic of this change. -- jlc */
1249 /* don't stop on /dev/console */
1250 if (file->f_op->write != redirected_tty_write &&
1251 current->signal->tty == tty) {
Eric W. Biedermanab521dc2007-02-12 00:53:00 -08001252 if (!tty->pgrp)
Alan Cox11a96d12008-10-13 10:46:24 +01001253 printk(KERN_ERR "n_tty_read: no tty->pgrp!\n");
Eric W. Biedermanab521dc2007-02-12 00:53:00 -08001254 else if (task_pgrp(current) != tty->pgrp) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255 if (is_ignored(SIGTTIN) ||
Eric W. Biederman3e7cd6c2007-02-12 00:52:58 -08001256 is_current_pgrp_orphaned())
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 return -EIO;
Eric W. Biedermanab521dc2007-02-12 00:53:00 -08001258 kill_pgrp(task_pgrp(current), SIGTTIN, 1);
Oleg Nesterov040b6362007-06-01 00:46:53 -07001259 set_thread_flag(TIF_SIGPENDING);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001260 return -ERESTARTSYS;
1261 }
1262 }
1263 return 0;
1264}
Alan Cox4edf1822008-02-08 04:18:44 -08001265
Linus Torvalds1da177e2005-04-16 15:20:36 -07001266
1267/**
Alan Cox11a96d12008-10-13 10:46:24 +01001268 * n_tty_read - read function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 * @tty: tty device
1270 * @file: file object
1271 * @buf: userspace buffer pointer
1272 * @nr: size of I/O
1273 *
1274 * Perform reads for the line discipline. We are guaranteed that the
1275 * line discipline will not be closed under us but we may get multiple
1276 * parallel readers and must handle this ourselves. We may also get
1277 * a hangup. Always called in user context, may sleep.
1278 *
1279 * This code must be sure never to sleep through a hangup.
1280 */
Alan Cox4edf1822008-02-08 04:18:44 -08001281
Alan Cox11a96d12008-10-13 10:46:24 +01001282static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283 unsigned char __user *buf, size_t nr)
1284{
1285 unsigned char __user *b = buf;
1286 DECLARE_WAITQUEUE(wait, current);
1287 int c;
1288 int minimum, time;
1289 ssize_t retval = 0;
1290 ssize_t size;
1291 long timeout;
1292 unsigned long flags;
Alan Cox04f378b2008-04-30 00:53:29 -07001293 int packet;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294
1295do_it_again:
1296
Alan Cox17b82062008-10-13 10:45:06 +01001297 BUG_ON(!tty->read_buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298
1299 c = job_control(tty, file);
Alan Cox4edf1822008-02-08 04:18:44 -08001300 if (c < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001301 return c;
Alan Cox4edf1822008-02-08 04:18:44 -08001302
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303 minimum = time = 0;
1304 timeout = MAX_SCHEDULE_TIMEOUT;
1305 if (!tty->icanon) {
1306 time = (HZ / 10) * TIME_CHAR(tty);
1307 minimum = MIN_CHAR(tty);
1308 if (minimum) {
1309 if (time)
1310 tty->minimum_to_wake = 1;
1311 else if (!waitqueue_active(&tty->read_wait) ||
1312 (tty->minimum_to_wake > minimum))
1313 tty->minimum_to_wake = minimum;
1314 } else {
1315 timeout = 0;
1316 if (time) {
1317 timeout = time;
1318 time = 0;
1319 }
1320 tty->minimum_to_wake = minimum = 1;
1321 }
1322 }
1323
1324 /*
1325 * Internal serialization of reads.
1326 */
1327 if (file->f_flags & O_NONBLOCK) {
Ingo Molnar70522e12006-03-23 03:00:31 -08001328 if (!mutex_trylock(&tty->atomic_read_lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329 return -EAGAIN;
Alan Cox4edf1822008-02-08 04:18:44 -08001330 } else {
Ingo Molnar70522e12006-03-23 03:00:31 -08001331 if (mutex_lock_interruptible(&tty->atomic_read_lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 return -ERESTARTSYS;
1333 }
Alan Cox04f378b2008-04-30 00:53:29 -07001334 packet = tty->packet;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335
1336 add_wait_queue(&tty->read_wait, &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001337 while (nr) {
1338 /* First test for status change. */
Alan Cox04f378b2008-04-30 00:53:29 -07001339 if (packet && tty->link->ctrl_status) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 unsigned char cs;
1341 if (b != buf)
1342 break;
Alan Cox04f378b2008-04-30 00:53:29 -07001343 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344 cs = tty->link->ctrl_status;
1345 tty->link->ctrl_status = 0;
Alan Cox04f378b2008-04-30 00:53:29 -07001346 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
Miloslav Trmac522ed772007-07-15 23:40:56 -07001347 if (tty_put_user(tty, cs, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 retval = -EFAULT;
1349 b--;
1350 break;
1351 }
1352 nr--;
1353 break;
1354 }
1355 /* This statement must be first before checking for input
1356 so that any interrupt will set the state back to
1357 TASK_RUNNING. */
1358 set_current_state(TASK_INTERRUPTIBLE);
Alan Cox4edf1822008-02-08 04:18:44 -08001359
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360 if (((minimum - (b - buf)) < tty->minimum_to_wake) &&
1361 ((minimum - (b - buf)) >= 1))
1362 tty->minimum_to_wake = (minimum - (b - buf));
Alan Cox4edf1822008-02-08 04:18:44 -08001363
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364 if (!input_available_p(tty, 0)) {
1365 if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
1366 retval = -EIO;
1367 break;
1368 }
1369 if (tty_hung_up_p(file))
1370 break;
1371 if (!timeout)
1372 break;
1373 if (file->f_flags & O_NONBLOCK) {
1374 retval = -EAGAIN;
1375 break;
1376 }
1377 if (signal_pending(current)) {
1378 retval = -ERESTARTSYS;
1379 break;
1380 }
Alan Cox04f378b2008-04-30 00:53:29 -07001381 /* FIXME: does n_tty_set_room need locking ? */
Alan Cox33f0f882006-01-09 20:54:13 -08001382 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001383 timeout = schedule_timeout(timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384 continue;
1385 }
1386 __set_current_state(TASK_RUNNING);
1387
1388 /* Deal with packet mode. */
Alan Cox04f378b2008-04-30 00:53:29 -07001389 if (packet && b == buf) {
Miloslav Trmac522ed772007-07-15 23:40:56 -07001390 if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391 retval = -EFAULT;
1392 b--;
1393 break;
1394 }
1395 nr--;
1396 }
1397
1398 if (tty->icanon) {
1399 /* N.B. avoid overrun if nr == 0 */
1400 while (nr && tty->read_cnt) {
Alan Cox4edf1822008-02-08 04:18:44 -08001401 int eol;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402
1403 eol = test_and_clear_bit(tty->read_tail,
1404 tty->read_flags);
1405 c = tty->read_buf[tty->read_tail];
1406 spin_lock_irqsave(&tty->read_lock, flags);
1407 tty->read_tail = ((tty->read_tail+1) &
1408 (N_TTY_BUF_SIZE-1));
1409 tty->read_cnt--;
1410 if (eol) {
1411 /* this test should be redundant:
1412 * we shouldn't be reading data if
1413 * canon_data is 0
1414 */
1415 if (--tty->canon_data < 0)
1416 tty->canon_data = 0;
1417 }
1418 spin_unlock_irqrestore(&tty->read_lock, flags);
1419
1420 if (!eol || (c != __DISABLED_CHAR)) {
Miloslav Trmac522ed772007-07-15 23:40:56 -07001421 if (tty_put_user(tty, c, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422 retval = -EFAULT;
1423 b--;
1424 break;
1425 }
1426 nr--;
1427 }
Miloslav Trmac522ed772007-07-15 23:40:56 -07001428 if (eol) {
1429 tty_audit_push(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430 break;
Miloslav Trmac522ed772007-07-15 23:40:56 -07001431 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001432 }
1433 if (retval)
1434 break;
1435 } else {
1436 int uncopied;
Alan Cox04f378b2008-04-30 00:53:29 -07001437 /* The copy function takes the read lock and handles
1438 locking internally for this case */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001439 uncopied = copy_from_read_buf(tty, &b, &nr);
1440 uncopied += copy_from_read_buf(tty, &b, &nr);
1441 if (uncopied) {
1442 retval = -EFAULT;
1443 break;
1444 }
1445 }
1446
1447 /* If there is enough space in the read buffer now, let the
1448 * low-level driver know. We use n_tty_chars_in_buffer() to
1449 * check the buffer, as it now knows about canonical mode.
1450 * Otherwise, if the driver is throttled and the line is
1451 * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
1452 * we won't get any more characters.
1453 */
Paul Mackerras289a1e92006-06-12 12:16:26 +10001454 if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) {
1455 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001456 check_unthrottle(tty);
Paul Mackerras289a1e92006-06-12 12:16:26 +10001457 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001458
1459 if (b - buf >= minimum)
1460 break;
1461 if (time)
1462 timeout = time;
1463 }
Ingo Molnar70522e12006-03-23 03:00:31 -08001464 mutex_unlock(&tty->atomic_read_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001465 remove_wait_queue(&tty->read_wait, &wait);
1466
1467 if (!waitqueue_active(&tty->read_wait))
1468 tty->minimum_to_wake = minimum;
1469
1470 __set_current_state(TASK_RUNNING);
1471 size = b - buf;
1472 if (size) {
1473 retval = size;
1474 if (nr)
Alan Cox4edf1822008-02-08 04:18:44 -08001475 clear_bit(TTY_PUSH, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476 } else if (test_and_clear_bit(TTY_PUSH, &tty->flags))
1477 goto do_it_again;
1478
Alan Cox33f0f882006-01-09 20:54:13 -08001479 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480 return retval;
1481}
1482
1483/**
Alan Cox11a96d12008-10-13 10:46:24 +01001484 * n_tty_write - write function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485 * @tty: tty device
1486 * @file: file object
1487 * @buf: userspace buffer pointer
1488 * @nr: size of I/O
1489 *
1490 * Write function of the terminal device. This is serialized with
1491 * respect to other write callers but not to termios changes, reads
1492 * and other such events. We must be careful with N_TTY as the receive
1493 * code will echo characters, thus calling driver write methods.
1494 *
1495 * This code must be sure never to sleep through a hangup.
1496 */
Alan Cox4edf1822008-02-08 04:18:44 -08001497
Alan Cox11a96d12008-10-13 10:46:24 +01001498static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
Alan Cox4edf1822008-02-08 04:18:44 -08001499 const unsigned char *buf, size_t nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001500{
1501 const unsigned char *b = buf;
1502 DECLARE_WAITQUEUE(wait, current);
1503 int c;
1504 ssize_t retval = 0;
1505
1506 /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
1507 if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) {
1508 retval = tty_check_change(tty);
1509 if (retval)
1510 return retval;
1511 }
1512
1513 add_wait_queue(&tty->write_wait, &wait);
1514 while (1) {
1515 set_current_state(TASK_INTERRUPTIBLE);
1516 if (signal_pending(current)) {
1517 retval = -ERESTARTSYS;
1518 break;
1519 }
1520 if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) {
1521 retval = -EIO;
1522 break;
1523 }
1524 if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
1525 while (nr > 0) {
1526 ssize_t num = opost_block(tty, b, nr);
1527 if (num < 0) {
1528 if (num == -EAGAIN)
1529 break;
1530 retval = num;
1531 goto break_out;
1532 }
1533 b += num;
1534 nr -= num;
1535 if (nr == 0)
1536 break;
1537 c = *b;
1538 if (opost(c, tty) < 0)
1539 break;
1540 b++; nr--;
1541 }
Alan Coxf34d7a52008-04-30 00:54:13 -07001542 if (tty->ops->flush_chars)
1543 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001544 } else {
Roman Zippeld6afe272005-07-07 17:56:55 -07001545 while (nr > 0) {
Alan Coxf34d7a52008-04-30 00:54:13 -07001546 c = tty->ops->write(tty, b, nr);
Roman Zippeld6afe272005-07-07 17:56:55 -07001547 if (c < 0) {
1548 retval = c;
1549 goto break_out;
1550 }
1551 if (!c)
1552 break;
1553 b += c;
1554 nr -= c;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001555 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001556 }
1557 if (!nr)
1558 break;
1559 if (file->f_flags & O_NONBLOCK) {
1560 retval = -EAGAIN;
1561 break;
1562 }
1563 schedule();
1564 }
1565break_out:
1566 __set_current_state(TASK_RUNNING);
1567 remove_wait_queue(&tty->write_wait, &wait);
1568 return (b - buf) ? b - buf : retval;
1569}
1570
1571/**
Alan Cox11a96d12008-10-13 10:46:24 +01001572 * n_tty_poll - poll method for N_TTY
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573 * @tty: terminal device
1574 * @file: file accessing it
1575 * @wait: poll table
1576 *
1577 * Called when the line discipline is asked to poll() for data or
1578 * for special events. This code is not serialized with respect to
1579 * other events save open/close.
1580 *
1581 * This code must be sure never to sleep through a hangup.
1582 * Called without the kernel lock held - fine
Linus Torvalds1da177e2005-04-16 15:20:36 -07001583 */
Alan Cox4edf1822008-02-08 04:18:44 -08001584
Alan Cox11a96d12008-10-13 10:46:24 +01001585static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
Alan Cox4edf1822008-02-08 04:18:44 -08001586 poll_table *wait)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001587{
1588 unsigned int mask = 0;
1589
1590 poll_wait(file, &tty->read_wait, wait);
1591 poll_wait(file, &tty->write_wait, wait);
1592 if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty)))
1593 mask |= POLLIN | POLLRDNORM;
1594 if (tty->packet && tty->link->ctrl_status)
1595 mask |= POLLPRI | POLLIN | POLLRDNORM;
1596 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
1597 mask |= POLLHUP;
1598 if (tty_hung_up_p(file))
1599 mask |= POLLHUP;
1600 if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) {
1601 if (MIN_CHAR(tty) && !TIME_CHAR(tty))
1602 tty->minimum_to_wake = MIN_CHAR(tty);
1603 else
1604 tty->minimum_to_wake = 1;
1605 }
Alan Coxf34d7a52008-04-30 00:54:13 -07001606 if (tty->ops->write && !tty_is_writelocked(tty) &&
1607 tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
1608 tty_write_room(tty) > 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001609 mask |= POLLOUT | POLLWRNORM;
1610 return mask;
1611}
1612
Alan Cox47afa7a2008-10-13 10:44:17 +01001613static unsigned long inq_canon(struct tty_struct *tty)
1614{
1615 int nr, head, tail;
1616
Alan Cox17b82062008-10-13 10:45:06 +01001617 if (!tty->canon_data)
Alan Cox47afa7a2008-10-13 10:44:17 +01001618 return 0;
1619 head = tty->canon_head;
1620 tail = tty->read_tail;
1621 nr = (head - tail) & (N_TTY_BUF_SIZE-1);
1622 /* Skip EOF-chars.. */
1623 while (head != tail) {
1624 if (test_bit(tail, tty->read_flags) &&
1625 tty->read_buf[tail] == __DISABLED_CHAR)
1626 nr--;
1627 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
1628 }
1629 return nr;
1630}
1631
1632static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
1633 unsigned int cmd, unsigned long arg)
1634{
1635 int retval;
1636
1637 switch (cmd) {
1638 case TIOCOUTQ:
1639 return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
1640 case TIOCINQ:
Alan Cox17b82062008-10-13 10:45:06 +01001641 /* FIXME: Locking */
Alan Cox47afa7a2008-10-13 10:44:17 +01001642 retval = tty->read_cnt;
1643 if (L_ICANON(tty))
1644 retval = inq_canon(tty);
1645 return put_user(retval, (unsigned int __user *) arg);
1646 default:
1647 return n_tty_ioctl_helper(tty, file, cmd, arg);
1648 }
1649}
1650
Alan Coxa352def2008-07-16 21:53:12 +01001651struct tty_ldisc_ops tty_ldisc_N_TTY = {
Paul Fulghume10cc1d2007-05-10 22:22:50 -07001652 .magic = TTY_LDISC_MAGIC,
1653 .name = "n_tty",
1654 .open = n_tty_open,
1655 .close = n_tty_close,
1656 .flush_buffer = n_tty_flush_buffer,
1657 .chars_in_buffer = n_tty_chars_in_buffer,
Alan Cox11a96d12008-10-13 10:46:24 +01001658 .read = n_tty_read,
1659 .write = n_tty_write,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07001660 .ioctl = n_tty_ioctl,
1661 .set_termios = n_tty_set_termios,
Alan Cox11a96d12008-10-13 10:46:24 +01001662 .poll = n_tty_poll,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07001663 .receive_buf = n_tty_receive_buf,
1664 .write_wakeup = n_tty_write_wakeup
Linus Torvalds1da177e2005-04-16 15:20:36 -07001665};
1666