blob: c222a561c5aceb0d3faeb3b42b5a9d85307cb0fa [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>
George Spelvin593fb1ae42013-02-12 02:00:43 -050052#include <linux/ratelimit.h>
Peter Hurley86e35ae2013-07-24 09:30:05 -040053#include <linux/vmalloc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
56/* number of characters left in xmit buffer before select has we have room */
57#define WAKEUP_CHARS 256
58
59/*
60 * This defines the low- and high-watermarks for throttling and
61 * unthrottling the TTY driver. These watermarks are used for
62 * controlling the space in the read buffer.
63 */
64#define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */
Thorsten Wißmannbbd20752011-12-08 17:47:33 +010065#define TTY_THRESHOLD_UNTHROTTLE 128
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
Joe Petersona88a69c2009-01-02 13:40:53 +000067/*
68 * Special byte codes used in the echo buffer to represent operations
69 * or special handling of characters. Bytes in the echo buffer that
70 * are not part of such special blocks are treated as normal character
71 * codes.
72 */
73#define ECHO_OP_START 0xff
74#define ECHO_OP_MOVE_BACK_COL 0x80
75#define ECHO_OP_SET_CANON_COL 0x81
76#define ECHO_OP_ERASE_TAB 0x82
77
Peter Hurleycbfd0342013-06-15 10:04:26 -040078#define ECHO_COMMIT_WATERMARK 256
79#define ECHO_BLOCK 256
80#define ECHO_DISCARD_WATERMARK N_TTY_BUF_SIZE - (ECHO_BLOCK + 32)
81
82
Peter Hurley32f13522013-06-15 09:14:17 -040083#undef N_TTY_TRACE
84#ifdef N_TTY_TRACE
85# define n_tty_trace(f, args...) trace_printk(f, ##args)
86#else
87# define n_tty_trace(f, args...)
88#endif
89
Jiri Slaby70ece7a2012-10-18 22:26:38 +020090struct n_tty_data {
Peter Hurleyfb7aa032013-06-15 09:14:30 -040091 /* producer-published */
92 size_t read_head;
93 size_t canon_head;
Peter Hurley9dfd16d2013-06-15 10:04:29 -040094 size_t echo_head;
95 size_t echo_commit;
Peter Hurley1bb9d562013-06-15 10:21:20 -040096 DECLARE_BITMAP(char_map, 256);
Peter Hurleyfb7aa032013-06-15 09:14:30 -040097
98 /* private to n_tty_receive_overrun (single-threaded) */
Jiri Slaby53c5ee22012-10-18 22:26:39 +020099 unsigned long overrun_time;
100 int num_overrun;
101
Peter Hurley24a89d12013-06-15 09:14:15 -0400102 /* non-atomic */
103 bool no_room;
104
Peter Hurleyfb7aa032013-06-15 09:14:30 -0400105 /* must hold exclusive termios_rwsem to reset these */
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200106 unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
Jiri Slaby3fe780b2012-10-18 22:26:40 +0200107
Peter Hurleyfb7aa032013-06-15 09:14:30 -0400108 /* shared by producer and consumer */
Peter Hurley20bafb32013-06-15 10:21:19 -0400109 char read_buf[N_TTY_BUF_SIZE];
Jiri Slaby3fe780b2012-10-18 22:26:40 +0200110 DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE);
Peter Hurley20bafb32013-06-15 10:21:19 -0400111 unsigned char echo_buf[N_TTY_BUF_SIZE];
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200112
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -0400113 int minimum_to_wake;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200114
Peter Hurleyfb7aa032013-06-15 09:14:30 -0400115 /* consumer-published */
116 size_t read_tail;
Peter Hurley40d5e092013-06-15 10:21:17 -0400117 size_t line_start;
Peter Hurleyfb7aa032013-06-15 09:14:30 -0400118
Peter Hurleyfb7aa032013-06-15 09:14:30 -0400119 /* protected by output lock */
120 unsigned int column;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200121 unsigned int canon_column;
Peter Hurley9dfd16d2013-06-15 10:04:29 -0400122 size_t echo_tail;
Jiri Slabybddc7152012-10-18 22:26:42 +0200123
124 struct mutex atomic_read_lock;
125 struct mutex output_lock;
Jiri Slaby70ece7a2012-10-18 22:26:38 +0200126};
127
Peter Hurleyce741172013-06-15 09:14:20 -0400128static inline size_t read_cnt(struct n_tty_data *ldata)
129{
Peter Hurleya2f73be2013-06-15 09:14:22 -0400130 return ldata->read_head - ldata->read_tail;
Peter Hurleyce741172013-06-15 09:14:20 -0400131}
132
Peter Hurleybc5a5e32013-06-15 09:14:21 -0400133static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i)
134{
135 return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)];
136}
137
138static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i)
139{
140 return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)];
141}
142
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400143static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i)
144{
145 return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
146}
147
148static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i)
149{
150 return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
151}
152
Miloslav Trmac522ed772007-07-15 23:40:56 -0700153static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
154 unsigned char __user *ptr)
155{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200156 struct n_tty_data *ldata = tty->disc_data;
157
158 tty_audit_add_data(tty, &x, 1, ldata->icanon);
Miloslav Trmac522ed772007-07-15 23:40:56 -0700159 return put_user(x, ptr);
160}
161
Peter Hurley24a89d12013-06-15 09:14:15 -0400162static int receive_room(struct tty_struct *tty)
Linus Torvalds55db4c62011-06-04 06:33:24 +0900163{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200164 struct n_tty_data *ldata = tty->disc_data;
Jaeden Amero090abf72012-07-27 08:43:11 -0500165 int left;
Peter Hurleyb8483052013-06-15 07:28:30 -0400166
Jaeden Amero090abf72012-07-27 08:43:11 -0500167 if (I_PARMRK(tty)) {
168 /* Multiply read_cnt by 3, since each byte might take up to
169 * three times as many spaces when PARMRK is set (depending on
170 * its flags, e.g. parity error). */
Peter Hurleyce741172013-06-15 09:14:20 -0400171 left = N_TTY_BUF_SIZE - read_cnt(ldata) * 3 - 1;
Jaeden Amero090abf72012-07-27 08:43:11 -0500172 } else
Peter Hurleyce741172013-06-15 09:14:20 -0400173 left = N_TTY_BUF_SIZE - read_cnt(ldata) - 1;
Jaeden Amero090abf72012-07-27 08:43:11 -0500174
Linus Torvalds55db4c62011-06-04 06:33:24 +0900175 /*
176 * If we are doing input canonicalization, and there are no
177 * pending newlines, let characters through without limit, so
178 * that erase characters will be handled. Other excess
179 * characters will be beeped.
180 */
181 if (left <= 0)
Peter Hurleya73d3d62013-06-15 09:14:25 -0400182 left = ldata->icanon && ldata->canon_head == ldata->read_tail;
Linus Torvalds55db4c62011-06-04 06:33:24 +0900183
Peter Hurley24a89d12013-06-15 09:14:15 -0400184 return left;
Peter Hurley7879a9f2013-06-15 07:28:31 -0400185}
186
Peter Hurley24a89d12013-06-15 09:14:15 -0400187/**
188 * n_tty_set_room - receive space
189 * @tty: terminal
190 *
191 * Re-schedules the flip buffer work if space just became available.
192 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400193 * Caller holds exclusive termios_rwsem
194 * or
195 * n_tty_read()/consumer path:
196 * holds non-exclusive termios_rwsem
Peter Hurley24a89d12013-06-15 09:14:15 -0400197 */
198
Peter Hurley7879a9f2013-06-15 07:28:31 -0400199static void n_tty_set_room(struct tty_struct *tty)
200{
Peter Hurley24a89d12013-06-15 09:14:15 -0400201 struct n_tty_data *ldata = tty->disc_data;
202
Linus Torvalds55db4c62011-06-04 06:33:24 +0900203 /* Did this open up the receive buffer? We may need to flip */
Peter Hurley24a89d12013-06-15 09:14:15 -0400204 if (unlikely(ldata->no_room) && receive_room(tty)) {
205 ldata->no_room = 0;
206
Jiri Slabyecbbfd42012-10-18 22:26:47 +0200207 WARN_RATELIMIT(tty->port->itty == NULL,
Sasha Levincadf7482012-10-25 14:26:35 -0400208 "scheduling with invalid itty\n");
Peter Hurley21622932013-03-11 16:44:21 -0400209 /* see if ldisc has been killed - if so, this means that
210 * even though the ldisc has been halted and ->buf.work
211 * cancelled, ->buf.work is about to be rescheduled
212 */
213 WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags),
214 "scheduling buffer work for halted ldisc\n");
Peter Hurleyf0f947c2013-06-15 09:14:36 -0400215 queue_work(system_unbound_wq, &tty->port->buf.work);
Jiri Slabyecbbfd42012-10-18 22:26:47 +0200216 }
Linus Torvalds55db4c62011-06-04 06:33:24 +0900217}
218
Peter Hurley9a4aec22013-06-15 09:14:32 -0400219static ssize_t chars_in_buffer(struct tty_struct *tty)
220{
221 struct n_tty_data *ldata = tty->disc_data;
222 ssize_t n = 0;
223
224 if (!ldata->icanon)
225 n = read_cnt(ldata);
226 else
227 n = ldata->canon_head - ldata->read_tail;
228 return n;
229}
230
Peter Hurleyee0bab82013-06-15 09:14:34 -0400231/**
232 * n_tty_write_wakeup - asynchronous I/O notifier
233 * @tty: tty device
234 *
235 * Required for the ptys, serial driver etc. since processes
236 * that attach themselves to the master and rely on ASYNC
237 * IO must be woken up
238 */
239
240static void n_tty_write_wakeup(struct tty_struct *tty)
241{
242 if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags))
243 kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
244}
245
Peter Hurley4a23a4d2013-06-15 10:21:22 -0400246static void n_tty_check_throttle(struct tty_struct *tty)
Peter Hurley6367ca72013-06-15 09:14:33 -0400247{
Peter Hurley3afb1b392013-07-23 08:47:30 -0400248 if (tty->driver->type == TTY_DRIVER_TYPE_PTY)
249 return;
Peter Hurley6367ca72013-06-15 09:14:33 -0400250 /*
251 * Check the remaining room for the input canonicalization
252 * mode. We don't want to throttle the driver if we're in
253 * canonical mode and don't have a newline yet!
254 */
255 while (1) {
256 int throttled;
257 tty_set_flow_change(tty, TTY_THROTTLE_SAFE);
258 if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE)
259 break;
260 throttled = tty_throttle_safe(tty);
261 if (!throttled)
262 break;
263 }
264 __tty_set_flow_change(tty, 0);
265}
266
Peter Hurley4b293492013-07-24 08:29:55 -0400267static void n_tty_check_unthrottle(struct tty_struct *tty)
Peter Hurley6367ca72013-06-15 09:14:33 -0400268{
Peter Hurley3afb1b392013-07-23 08:47:30 -0400269 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
270 tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) {
271 if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
272 return;
273 if (!tty->count)
274 return;
275 n_tty_set_room(tty);
276 n_tty_write_wakeup(tty->link);
277 wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT);
278 return;
279 }
280
Peter Hurley6367ca72013-06-15 09:14:33 -0400281 /* If there is enough space in the read buffer now, let the
282 * low-level driver know. We use chars_in_buffer() to
283 * check the buffer, as it now knows about canonical mode.
284 * Otherwise, if the driver is throttled and the line is
285 * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
286 * we won't get any more characters.
287 */
288
289 while (1) {
290 int unthrottled;
291 tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE);
292 if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
293 break;
294 if (!tty->count)
295 break;
296 n_tty_set_room(tty);
297 unthrottled = tty_unthrottle_safe(tty);
298 if (!unthrottled)
299 break;
300 }
301 __tty_set_flow_change(tty, 0);
302}
303
Alan Cox17b82062008-10-13 10:45:06 +0100304/**
305 * put_tty_queue - add character to tty
306 * @c: character
Jiri Slaby57c94122012-10-18 22:26:43 +0200307 * @ldata: n_tty data
Alan Cox17b82062008-10-13 10:45:06 +0100308 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400309 * Add a character to the tty read_buf queue.
310 *
311 * n_tty_receive_buf()/producer path:
312 * caller holds non-exclusive termios_rwsem
313 * modifies read_head
314 *
315 * read_head is only considered 'published' if canonical mode is
316 * not active.
Alan Cox17b82062008-10-13 10:45:06 +0100317 */
318
Peter Hurley19e2ad62013-07-24 08:29:54 -0400319static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320{
Peter Hurley19e2ad62013-07-24 08:29:54 -0400321 *read_buf_addr(ldata, ldata->read_head++) = c;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322}
323
324/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 * reset_buffer_flags - reset buffer state
326 * @tty: terminal to reset
327 *
Peter Hurley25518c62013-03-11 16:44:31 -0400328 * Reset the read buffer counters and clear the flags.
329 * Called from n_tty_open() and n_tty_flush_buffer().
Alan Cox17b82062008-10-13 10:45:06 +0100330 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400331 * Locking: caller holds exclusive termios_rwsem
332 * (or locking is not required)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000334
Peter Hurleyb66f4fa2013-03-11 16:44:32 -0400335static void reset_buffer_flags(struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336{
Peter Hurleya73d3d62013-06-15 09:14:25 -0400337 ldata->read_head = ldata->canon_head = ldata->read_tail = 0;
Peter Hurley17bd7902013-06-15 10:04:24 -0400338 ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0;
Peter Hurley40d5e092013-06-15 10:21:17 -0400339 ldata->line_start = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000340
Peter Hurleya73d3d62013-06-15 09:14:25 -0400341 ldata->erasing = 0;
Jiri Slaby3fe780b2012-10-18 22:26:40 +0200342 bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343}
344
Peter Hurleya30737a2013-03-11 16:44:22 -0400345static void n_tty_packet_mode_flush(struct tty_struct *tty)
346{
347 unsigned long flags;
348
349 spin_lock_irqsave(&tty->ctrl_lock, flags);
350 if (tty->link->packet) {
351 tty->ctrl_status |= TIOCPKT_FLUSHREAD;
352 wake_up_interruptible(&tty->link->read_wait);
353 }
354 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
355}
356
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357/**
358 * n_tty_flush_buffer - clean input queue
359 * @tty: terminal device
360 *
Peter Hurley25518c62013-03-11 16:44:31 -0400361 * Flush the input buffer. Called when the tty layer wants the
362 * buffer flushed (eg at hangup) or when the N_TTY line discipline
363 * internally has to clean the pending queue (for example some signals).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400365 * Holds termios_rwsem to exclude producer/consumer while
366 * buffer indices are reset.
367 *
368 * Locking: ctrl_lock, exclusive termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 */
Alan Cox4edf1822008-02-08 04:18:44 -0800370
371static void n_tty_flush_buffer(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372{
Peter Hurley6d76bd22013-06-15 09:14:26 -0400373 down_write(&tty->termios_rwsem);
Peter Hurleyb66f4fa2013-03-11 16:44:32 -0400374 reset_buffer_flags(tty->disc_data);
375 n_tty_set_room(tty);
Alan Cox4edf1822008-02-08 04:18:44 -0800376
Peter Hurleya30737a2013-03-11 16:44:22 -0400377 if (tty->link)
378 n_tty_packet_mode_flush(tty);
Peter Hurley6d76bd22013-06-15 09:14:26 -0400379 up_write(&tty->termios_rwsem);
380}
381
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382/**
383 * n_tty_chars_in_buffer - report available bytes
384 * @tty: tty device
385 *
386 * Report the number of characters buffered to be delivered to user
Alan Cox4edf1822008-02-08 04:18:44 -0800387 * at this instant in time.
Alan Cox17b82062008-10-13 10:45:06 +0100388 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400389 * Locking: exclusive termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 */
Alan Cox4edf1822008-02-08 04:18:44 -0800391
Peter Hurleya19d0c62013-06-15 09:14:18 -0400392static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
393{
Peter Hurley6d76bd22013-06-15 09:14:26 -0400394 ssize_t n;
395
Peter Hurley47534082013-06-15 09:14:19 -0400396 WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__);
Peter Hurley6d76bd22013-06-15 09:14:26 -0400397
398 down_write(&tty->termios_rwsem);
399 n = chars_in_buffer(tty);
400 up_write(&tty->termios_rwsem);
401 return n;
Peter Hurleya19d0c62013-06-15 09:14:18 -0400402}
403
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404/**
405 * is_utf8_continuation - utf8 multibyte check
406 * @c: byte to check
407 *
408 * Returns true if the utf8 character 'c' is a multibyte continuation
409 * character. We use this to correctly compute the on screen size
410 * of the character when printing
411 */
Alan Cox4edf1822008-02-08 04:18:44 -0800412
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413static inline int is_utf8_continuation(unsigned char c)
414{
415 return (c & 0xc0) == 0x80;
416}
417
418/**
419 * is_continuation - multibyte check
420 * @c: byte to check
421 *
422 * Returns true if the utf8 character 'c' is a multibyte continuation
423 * character and the terminal is in unicode mode.
424 */
Alan Cox4edf1822008-02-08 04:18:44 -0800425
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426static inline int is_continuation(unsigned char c, struct tty_struct *tty)
427{
428 return I_IUTF8(tty) && is_utf8_continuation(c);
429}
430
431/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000432 * do_output_char - output one character
433 * @c: character (or partial unicode symbol)
434 * @tty: terminal device
435 * @space: space available in tty driver write buffer
436 *
437 * This is a helper function that handles one output character
438 * (including special characters like TAB, CR, LF, etc.),
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600439 * doing OPOST processing and putting the results in the
440 * tty driver's write buffer.
Joe Petersona88a69c2009-01-02 13:40:53 +0000441 *
442 * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY
443 * and NLDLY. They simply aren't relevant in the world today.
444 * If you ever need them, add them here.
445 *
446 * Returns the number of bytes of buffer space used or -1 if
447 * no space left.
448 *
449 * Locking: should be called under the output_lock to protect
450 * the column state and space left in the buffer
451 */
452
453static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
454{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200455 struct n_tty_data *ldata = tty->disc_data;
Joe Petersona88a69c2009-01-02 13:40:53 +0000456 int spaces;
457
458 if (!space)
459 return -1;
Alan Cox300a6202009-01-02 13:41:04 +0000460
Joe Petersona88a69c2009-01-02 13:40:53 +0000461 switch (c) {
462 case '\n':
463 if (O_ONLRET(tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200464 ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000465 if (O_ONLCR(tty)) {
466 if (space < 2)
467 return -1;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200468 ldata->canon_column = ldata->column = 0;
Linus Torvalds37f81fa2009-09-05 12:46:07 -0700469 tty->ops->write(tty, "\r\n", 2);
Joe Petersona88a69c2009-01-02 13:40:53 +0000470 return 2;
471 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200472 ldata->canon_column = ldata->column;
Joe Petersona88a69c2009-01-02 13:40:53 +0000473 break;
474 case '\r':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200475 if (O_ONOCR(tty) && ldata->column == 0)
Joe Petersona88a69c2009-01-02 13:40:53 +0000476 return 0;
477 if (O_OCRNL(tty)) {
478 c = '\n';
479 if (O_ONLRET(tty))
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200480 ldata->canon_column = ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000481 break;
482 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200483 ldata->canon_column = ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000484 break;
485 case '\t':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200486 spaces = 8 - (ldata->column & 7);
Joe Petersona88a69c2009-01-02 13:40:53 +0000487 if (O_TABDLY(tty) == XTABS) {
488 if (space < spaces)
489 return -1;
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200490 ldata->column += spaces;
Joe Petersona88a69c2009-01-02 13:40:53 +0000491 tty->ops->write(tty, " ", spaces);
492 return spaces;
493 }
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200494 ldata->column += spaces;
Joe Petersona88a69c2009-01-02 13:40:53 +0000495 break;
496 case '\b':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200497 if (ldata->column > 0)
498 ldata->column--;
Joe Petersona88a69c2009-01-02 13:40:53 +0000499 break;
500 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000501 if (!iscntrl(c)) {
502 if (O_OLCUC(tty))
503 c = toupper(c);
504 if (!is_continuation(c, tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200505 ldata->column++;
Joe Petersona59c0d62009-01-02 13:43:25 +0000506 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000507 break;
508 }
509
510 tty_put_char(tty, c);
511 return 1;
512}
513
514/**
515 * process_output - output post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 * @c: character (or partial unicode symbol)
517 * @tty: terminal device
518 *
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600519 * Output one character with OPOST processing.
520 * Returns -1 when the output device is full and the character
521 * must be retried.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000523 * Locking: output_lock to protect column state and space left
524 * (also, this is called from n_tty_write under the
525 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 */
Alan Cox4edf1822008-02-08 04:18:44 -0800527
Joe Petersona88a69c2009-01-02 13:40:53 +0000528static int process_output(unsigned char c, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529{
Jiri Slabybddc7152012-10-18 22:26:42 +0200530 struct n_tty_data *ldata = tty->disc_data;
Joe Petersona88a69c2009-01-02 13:40:53 +0000531 int space, retval;
532
Jiri Slabybddc7152012-10-18 22:26:42 +0200533 mutex_lock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534
Alan Coxf34d7a52008-04-30 00:54:13 -0700535 space = tty_write_room(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +0000536 retval = do_output_char(c, tty, space);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537
Jiri Slabybddc7152012-10-18 22:26:42 +0200538 mutex_unlock(&ldata->output_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000539 if (retval < 0)
540 return -1;
541 else
542 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543}
544
545/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000546 * process_output_block - block post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 * @tty: terminal device
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600548 * @buf: character buffer
549 * @nr: number of bytes to output
550 *
551 * Output a block of characters with OPOST processing.
552 * Returns the number of characters output.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 *
554 * This path is used to speed up block console writes, among other
555 * things when processing blocks of output data. It handles only
556 * the simple cases normally found and helps to generate blocks of
557 * symbols for the console driver and thus improve performance.
558 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000559 * Locking: output_lock to protect column state and space left
560 * (also, this is called from n_tty_write under the
561 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 */
Alan Cox4edf1822008-02-08 04:18:44 -0800563
Joe Petersona88a69c2009-01-02 13:40:53 +0000564static ssize_t process_output_block(struct tty_struct *tty,
565 const unsigned char *buf, unsigned int nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200567 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 int space;
Thorsten Wißmannbbd20752011-12-08 17:47:33 +0100569 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 const unsigned char *cp;
571
Jiri Slabybddc7152012-10-18 22:26:42 +0200572 mutex_lock(&ldata->output_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000573
Alan Coxf34d7a52008-04-30 00:54:13 -0700574 space = tty_write_room(tty);
Alan Cox300a6202009-01-02 13:41:04 +0000575 if (!space) {
Jiri Slabybddc7152012-10-18 22:26:42 +0200576 mutex_unlock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 return 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000578 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 if (nr > space)
580 nr = space;
581
582 for (i = 0, cp = buf; i < nr; i++, cp++) {
Joe Petersona59c0d62009-01-02 13:43:25 +0000583 unsigned char c = *cp;
584
585 switch (c) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 case '\n':
587 if (O_ONLRET(tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200588 ldata->column = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 if (O_ONLCR(tty))
590 goto break_out;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200591 ldata->canon_column = ldata->column;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 break;
593 case '\r':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200594 if (O_ONOCR(tty) && ldata->column == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 goto break_out;
596 if (O_OCRNL(tty))
597 goto break_out;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200598 ldata->canon_column = ldata->column = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 break;
600 case '\t':
601 goto break_out;
602 case '\b':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200603 if (ldata->column > 0)
604 ldata->column--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 break;
606 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000607 if (!iscntrl(c)) {
608 if (O_OLCUC(tty))
609 goto break_out;
610 if (!is_continuation(c, tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200611 ldata->column++;
Joe Petersona59c0d62009-01-02 13:43:25 +0000612 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 break;
614 }
615 }
616break_out:
Alan Coxf34d7a52008-04-30 00:54:13 -0700617 i = tty->ops->write(tty, buf, i);
Joe Petersona88a69c2009-01-02 13:40:53 +0000618
Jiri Slabybddc7152012-10-18 22:26:42 +0200619 mutex_unlock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 return i;
621}
622
Joe Petersona88a69c2009-01-02 13:40:53 +0000623/**
624 * process_echoes - write pending echo characters
625 * @tty: terminal device
626 *
627 * Write previously buffered echo (and other ldisc-generated)
628 * characters to the tty.
629 *
630 * Characters generated by the ldisc (including echoes) need to
631 * be buffered because the driver's write buffer can fill during
632 * heavy program output. Echoing straight to the driver will
633 * often fail under these conditions, causing lost characters and
634 * resulting mismatches of ldisc state information.
635 *
636 * Since the ldisc state must represent the characters actually sent
637 * to the driver at the time of the write, operations like certain
638 * changes in column state are also saved in the buffer and executed
639 * here.
640 *
641 * A circular fifo buffer is used so that the most recent characters
642 * are prioritized. Also, when control characters are echoed with a
643 * prefixed "^", the pair is treated atomically and thus not separated.
644 *
Peter Hurley019ebdf2013-06-15 10:04:25 -0400645 * Locking: callers must hold output_lock
Joe Petersona88a69c2009-01-02 13:40:53 +0000646 */
647
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400648static size_t __process_echoes(struct tty_struct *tty)
Joe Petersona88a69c2009-01-02 13:40:53 +0000649{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200650 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400651 int space, old_space;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400652 size_t tail;
Joe Petersona88a69c2009-01-02 13:40:53 +0000653 unsigned char c;
Joe Petersona88a69c2009-01-02 13:40:53 +0000654
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400655 old_space = space = tty_write_room(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +0000656
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400657 tail = ldata->echo_tail;
Peter Hurley29c7c5c2013-06-15 10:04:28 -0400658 while (ldata->echo_commit != tail) {
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400659 c = echo_buf(ldata, tail);
Joe Petersona88a69c2009-01-02 13:40:53 +0000660 if (c == ECHO_OP_START) {
661 unsigned char op;
Joe Petersona88a69c2009-01-02 13:40:53 +0000662 int no_space_left = 0;
663
664 /*
665 * If the buffer byte is the start of a multi-byte
666 * operation, get the next byte, which is either the
667 * op code or a control character value.
668 */
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400669 op = echo_buf(ldata, tail + 1);
Alan Cox300a6202009-01-02 13:41:04 +0000670
Joe Petersona88a69c2009-01-02 13:40:53 +0000671 switch (op) {
672 unsigned int num_chars, num_bs;
673
674 case ECHO_OP_ERASE_TAB:
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400675 num_chars = echo_buf(ldata, tail + 2);
Joe Petersona88a69c2009-01-02 13:40:53 +0000676
677 /*
678 * Determine how many columns to go back
679 * in order to erase the tab.
680 * This depends on the number of columns
681 * used by other characters within the tab
682 * area. If this (modulo 8) count is from
683 * the start of input rather than from a
684 * previous tab, we offset by canon column.
685 * Otherwise, tab spacing is normal.
686 */
687 if (!(num_chars & 0x80))
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200688 num_chars += ldata->canon_column;
Joe Petersona88a69c2009-01-02 13:40:53 +0000689 num_bs = 8 - (num_chars & 7);
690
691 if (num_bs > space) {
692 no_space_left = 1;
693 break;
694 }
695 space -= num_bs;
696 while (num_bs--) {
697 tty_put_char(tty, '\b');
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200698 if (ldata->column > 0)
699 ldata->column--;
Joe Petersona88a69c2009-01-02 13:40:53 +0000700 }
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400701 tail += 3;
Joe Petersona88a69c2009-01-02 13:40:53 +0000702 break;
703
704 case ECHO_OP_SET_CANON_COL:
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200705 ldata->canon_column = ldata->column;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400706 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000707 break;
708
709 case ECHO_OP_MOVE_BACK_COL:
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200710 if (ldata->column > 0)
711 ldata->column--;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400712 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000713 break;
714
715 case ECHO_OP_START:
716 /* This is an escaped echo op start code */
717 if (!space) {
718 no_space_left = 1;
719 break;
720 }
721 tty_put_char(tty, ECHO_OP_START);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200722 ldata->column++;
Joe Petersona88a69c2009-01-02 13:40:53 +0000723 space--;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400724 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000725 break;
726
727 default:
Joe Petersona88a69c2009-01-02 13:40:53 +0000728 /*
Joe Peterson62b26352009-09-09 15:03:47 -0600729 * If the op is not a special byte code,
730 * it is a ctrl char tagged to be echoed
731 * as "^X" (where X is the letter
732 * representing the control char).
733 * Note that we must ensure there is
734 * enough space for the whole ctrl pair.
735 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000736 */
Joe Peterson62b26352009-09-09 15:03:47 -0600737 if (space < 2) {
738 no_space_left = 1;
739 break;
740 }
741 tty_put_char(tty, '^');
742 tty_put_char(tty, op ^ 0100);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200743 ldata->column += 2;
Joe Peterson62b26352009-09-09 15:03:47 -0600744 space -= 2;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400745 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000746 }
747
748 if (no_space_left)
749 break;
750 } else {
Peter Hurley582f5592013-05-17 12:49:48 -0400751 if (O_OPOST(tty)) {
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600752 int retval = do_output_char(c, tty, space);
753 if (retval < 0)
754 break;
755 space -= retval;
756 } else {
757 if (!space)
758 break;
759 tty_put_char(tty, c);
760 space -= 1;
761 }
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400762 tail += 1;
Joe Petersona88a69c2009-01-02 13:40:53 +0000763 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000764 }
765
Peter Hurleycbfd0342013-06-15 10:04:26 -0400766 /* If the echo buffer is nearly full (so that the possibility exists
767 * of echo overrun before the next commit), then discard enough
768 * data at the tail to prevent a subsequent overrun */
769 while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) {
Roel Kluinc476f652013-10-11 22:08:49 +0200770 if (echo_buf(ldata, tail) == ECHO_OP_START) {
Peter Hurley6f222532013-11-08 09:42:18 -0500771 if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB)
Peter Hurleycbfd0342013-06-15 10:04:26 -0400772 tail += 3;
773 else
774 tail += 2;
775 } else
776 tail++;
777 }
778
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400779 ldata->echo_tail = tail;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400780 return old_space - space;
Joe Petersona88a69c2009-01-02 13:40:53 +0000781}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782
Peter Hurley17bd7902013-06-15 10:04:24 -0400783static void commit_echoes(struct tty_struct *tty)
784{
785 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400786 size_t nr, old, echoed;
Peter Hurleycbfd0342013-06-15 10:04:26 -0400787 size_t head;
788
789 head = ldata->echo_head;
790 old = ldata->echo_commit - ldata->echo_tail;
791
792 /* Process committed echoes if the accumulated # of bytes
793 * is over the threshold (and try again each time another
794 * block is accumulated) */
795 nr = head - ldata->echo_tail;
796 if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK))
797 return;
Peter Hurley17bd7902013-06-15 10:04:24 -0400798
Peter Hurley019ebdf2013-06-15 10:04:25 -0400799 mutex_lock(&ldata->output_lock);
Peter Hurleycbfd0342013-06-15 10:04:26 -0400800 ldata->echo_commit = head;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400801 echoed = __process_echoes(tty);
Peter Hurley019ebdf2013-06-15 10:04:25 -0400802 mutex_unlock(&ldata->output_lock);
803
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400804 if (echoed && tty->ops->flush_chars)
Peter Hurley019ebdf2013-06-15 10:04:25 -0400805 tty->ops->flush_chars(tty);
806}
807
808static void process_echoes(struct tty_struct *tty)
809{
810 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400811 size_t echoed;
Peter Hurley019ebdf2013-06-15 10:04:25 -0400812
813 if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_tail)
814 return;
815
816 mutex_lock(&ldata->output_lock);
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400817 echoed = __process_echoes(tty);
Peter Hurley019ebdf2013-06-15 10:04:25 -0400818 mutex_unlock(&ldata->output_lock);
819
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400820 if (echoed && tty->ops->flush_chars)
Peter Hurley019ebdf2013-06-15 10:04:25 -0400821 tty->ops->flush_chars(tty);
Peter Hurley17bd7902013-06-15 10:04:24 -0400822}
823
Peter Hurleycbfd0342013-06-15 10:04:26 -0400824static void flush_echoes(struct tty_struct *tty)
825{
826 struct n_tty_data *ldata = tty->disc_data;
827
828 if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_head)
829 return;
830
831 mutex_lock(&ldata->output_lock);
832 ldata->echo_commit = ldata->echo_head;
833 __process_echoes(tty);
834 mutex_unlock(&ldata->output_lock);
835}
836
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000838 * add_echo_byte - add a byte to the echo buffer
839 * @c: unicode byte to echo
Jiri Slaby57c94122012-10-18 22:26:43 +0200840 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000841 *
842 * Add a character or operation byte to the echo buffer.
Joe Petersona88a69c2009-01-02 13:40:53 +0000843 */
844
Peter Hurleycbfd0342013-06-15 10:04:26 -0400845static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000846{
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400847 *echo_buf_addr(ldata, ldata->echo_head++) = c;
Joe Petersona88a69c2009-01-02 13:40:53 +0000848}
849
850/**
851 * echo_move_back_col - add operation to move back a column
Jiri Slaby57c94122012-10-18 22:26:43 +0200852 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000853 *
854 * Add an operation to the echo buffer to move back one column.
Joe Petersona88a69c2009-01-02 13:40:53 +0000855 */
856
Jiri Slaby57c94122012-10-18 22:26:43 +0200857static void echo_move_back_col(struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000858{
Jiri Slaby57c94122012-10-18 22:26:43 +0200859 add_echo_byte(ECHO_OP_START, ldata);
860 add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000861}
862
863/**
864 * echo_set_canon_col - add operation to set the canon column
Jiri Slaby57c94122012-10-18 22:26:43 +0200865 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000866 *
867 * Add an operation to the echo buffer to set the canon column
868 * to the current column.
Joe Petersona88a69c2009-01-02 13:40:53 +0000869 */
870
Jiri Slaby57c94122012-10-18 22:26:43 +0200871static void echo_set_canon_col(struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000872{
Jiri Slaby57c94122012-10-18 22:26:43 +0200873 add_echo_byte(ECHO_OP_START, ldata);
874 add_echo_byte(ECHO_OP_SET_CANON_COL, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000875}
876
877/**
878 * echo_erase_tab - add operation to erase a tab
879 * @num_chars: number of character columns already used
880 * @after_tab: true if num_chars starts after a previous tab
Jiri Slaby57c94122012-10-18 22:26:43 +0200881 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000882 *
883 * Add an operation to the echo buffer to erase a tab.
884 *
885 * Called by the eraser function, which knows how many character
886 * columns have been used since either a previous tab or the start
887 * of input. This information will be used later, along with
888 * canon column (if applicable), to go back the correct number
889 * of columns.
Joe Petersona88a69c2009-01-02 13:40:53 +0000890 */
891
892static void echo_erase_tab(unsigned int num_chars, int after_tab,
Jiri Slaby57c94122012-10-18 22:26:43 +0200893 struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000894{
Jiri Slaby57c94122012-10-18 22:26:43 +0200895 add_echo_byte(ECHO_OP_START, ldata);
896 add_echo_byte(ECHO_OP_ERASE_TAB, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000897
898 /* We only need to know this modulo 8 (tab spacing) */
899 num_chars &= 7;
900
901 /* Set the high bit as a flag if num_chars is after a previous tab */
902 if (after_tab)
903 num_chars |= 0x80;
Alan Cox300a6202009-01-02 13:41:04 +0000904
Jiri Slaby57c94122012-10-18 22:26:43 +0200905 add_echo_byte(num_chars, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000906}
907
908/**
909 * echo_char_raw - echo a character raw
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 * @c: unicode byte to echo
911 * @tty: terminal device
912 *
Alan Cox4edf1822008-02-08 04:18:44 -0800913 * Echo user input back onto the screen. This must be called only when
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914 * L_ECHO(tty) is true. Called from the driver receive_buf path.
Alan Cox17b82062008-10-13 10:45:06 +0100915 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000916 * This variant does not treat control characters specially.
Joe Petersona88a69c2009-01-02 13:40:53 +0000917 */
918
Jiri Slaby57c94122012-10-18 22:26:43 +0200919static void echo_char_raw(unsigned char c, struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000920{
Joe Petersona88a69c2009-01-02 13:40:53 +0000921 if (c == ECHO_OP_START) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200922 add_echo_byte(ECHO_OP_START, ldata);
923 add_echo_byte(ECHO_OP_START, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000924 } else {
Jiri Slaby57c94122012-10-18 22:26:43 +0200925 add_echo_byte(c, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000926 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000927}
928
929/**
930 * echo_char - echo a character
931 * @c: unicode byte to echo
932 * @tty: terminal device
933 *
934 * Echo user input back onto the screen. This must be called only when
935 * L_ECHO(tty) is true. Called from the driver receive_buf path.
936 *
Joe Peterson62b26352009-09-09 15:03:47 -0600937 * This variant tags control characters to be echoed as "^X"
938 * (where X is the letter representing the control char).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939 */
940
941static void echo_char(unsigned char c, struct tty_struct *tty)
942{
Jiri Slabybddc7152012-10-18 22:26:42 +0200943 struct n_tty_data *ldata = tty->disc_data;
944
Joe Petersona88a69c2009-01-02 13:40:53 +0000945 if (c == ECHO_OP_START) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200946 add_echo_byte(ECHO_OP_START, ldata);
947 add_echo_byte(ECHO_OP_START, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000948 } else {
Joe Peterson62b26352009-09-09 15:03:47 -0600949 if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t')
Jiri Slaby57c94122012-10-18 22:26:43 +0200950 add_echo_byte(ECHO_OP_START, ldata);
951 add_echo_byte(c, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000952 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953}
954
Alan Cox17b82062008-10-13 10:45:06 +0100955/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000956 * finish_erasing - complete erase
Jiri Slaby57c94122012-10-18 22:26:43 +0200957 * @ldata: n_tty data
Alan Cox17b82062008-10-13 10:45:06 +0100958 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000959
Jiri Slaby57c94122012-10-18 22:26:43 +0200960static inline void finish_erasing(struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200962 if (ldata->erasing) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200963 echo_char_raw('/', ldata);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200964 ldata->erasing = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965 }
966}
967
968/**
969 * eraser - handle erase function
970 * @c: character input
971 * @tty: terminal device
972 *
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200973 * Perform erase and necessary output when an erase character is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974 * present in the stream from the driver layer. Handles the complexities
975 * of UTF-8 multibyte symbols.
Alan Cox17b82062008-10-13 10:45:06 +0100976 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400977 * n_tty_receive_buf()/producer path:
978 * caller holds non-exclusive termios_rwsem
979 * modifies read_head
980 *
981 * Modifying the read_head is not considered a publish in this context
982 * because canonical mode is active -- only canon_head publishes
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983 */
Alan Cox4edf1822008-02-08 04:18:44 -0800984
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985static void eraser(unsigned char c, struct tty_struct *tty)
986{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200987 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988 enum { ERASE, WERASE, KILL } kill_type;
Peter Hurleybc5a5e32013-06-15 09:14:21 -0400989 size_t head;
990 size_t cnt;
991 int seen_alnums;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200993 if (ldata->read_head == ldata->canon_head) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +0000994 /* process_output('\a', tty); */ /* what do you think? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 return;
996 }
997 if (c == ERASE_CHAR(tty))
998 kill_type = ERASE;
999 else if (c == WERASE_CHAR(tty))
1000 kill_type = WERASE;
1001 else {
1002 if (!L_ECHO(tty)) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001003 ldata->read_head = ldata->canon_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 return;
1005 }
1006 if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001007 ldata->read_head = ldata->canon_head;
Jiri Slaby57c94122012-10-18 22:26:43 +02001008 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 echo_char(KILL_CHAR(tty), tty);
1010 /* Add a newline if ECHOK is on and ECHOKE is off. */
1011 if (L_ECHOK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001012 echo_char_raw('\n', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 return;
1014 }
1015 kill_type = KILL;
1016 }
1017
1018 seen_alnums = 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001019 while (ldata->read_head != ldata->canon_head) {
1020 head = ldata->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021
1022 /* erase a single possibly multibyte character */
1023 do {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001024 head--;
1025 c = read_buf(ldata, head);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001026 } while (is_continuation(c, tty) && head != ldata->canon_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001027
1028 /* do not partially erase */
1029 if (is_continuation(c, tty))
1030 break;
1031
1032 if (kill_type == WERASE) {
1033 /* Equivalent to BSD's ALTWERASE. */
1034 if (isalnum(c) || c == '_')
1035 seen_alnums++;
1036 else if (seen_alnums)
1037 break;
1038 }
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001039 cnt = ldata->read_head - head;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001040 ldata->read_head = head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041 if (L_ECHO(tty)) {
1042 if (L_ECHOPRT(tty)) {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001043 if (!ldata->erasing) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001044 echo_char_raw('\\', ldata);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001045 ldata->erasing = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 }
1047 /* if cnt > 1, output a multi-byte character */
1048 echo_char(c, tty);
1049 while (--cnt > 0) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001050 head++;
1051 echo_char_raw(read_buf(ldata, head), ldata);
Jiri Slaby57c94122012-10-18 22:26:43 +02001052 echo_move_back_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001053 }
1054 } else if (kill_type == ERASE && !L_ECHOE(tty)) {
1055 echo_char(ERASE_CHAR(tty), tty);
1056 } else if (c == '\t') {
Joe Petersona88a69c2009-01-02 13:40:53 +00001057 unsigned int num_chars = 0;
1058 int after_tab = 0;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001059 size_t tail = ldata->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001060
Joe Petersona88a69c2009-01-02 13:40:53 +00001061 /*
1062 * Count the columns used for characters
1063 * since the start of input or after a
1064 * previous tab.
1065 * This info is used to go back the correct
1066 * number of columns.
1067 */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001068 while (tail != ldata->canon_head) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001069 tail--;
1070 c = read_buf(ldata, tail);
Joe Petersona88a69c2009-01-02 13:40:53 +00001071 if (c == '\t') {
1072 after_tab = 1;
1073 break;
Alan Cox300a6202009-01-02 13:41:04 +00001074 } else if (iscntrl(c)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001075 if (L_ECHOCTL(tty))
Joe Petersona88a69c2009-01-02 13:40:53 +00001076 num_chars += 2;
1077 } else if (!is_continuation(c, tty)) {
1078 num_chars++;
1079 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 }
Jiri Slaby57c94122012-10-18 22:26:43 +02001081 echo_erase_tab(num_chars, after_tab, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082 } else {
1083 if (iscntrl(c) && L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001084 echo_char_raw('\b', ldata);
1085 echo_char_raw(' ', ldata);
1086 echo_char_raw('\b', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 }
1088 if (!iscntrl(c) || L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001089 echo_char_raw('\b', ldata);
1090 echo_char_raw(' ', ldata);
1091 echo_char_raw('\b', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 }
1093 }
1094 }
1095 if (kill_type == ERASE)
1096 break;
1097 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001098 if (ldata->read_head == ldata->canon_head && L_ECHO(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001099 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100}
1101
1102/**
1103 * isig - handle the ISIG optio
1104 * @sig: signal
1105 * @tty: terminal
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106 *
Peter Hurley8c985d12013-03-06 08:38:19 -05001107 * Called when a signal is being sent due to terminal input.
1108 * Called from the driver receive_buf path so serialized.
Alan Cox17b82062008-10-13 10:45:06 +01001109 *
Peter Hurley8c985d12013-03-06 08:38:19 -05001110 * Locking: ctrl_lock
Linus Torvalds1da177e2005-04-16 15:20:36 -07001111 */
Alan Cox4edf1822008-02-08 04:18:44 -08001112
Peter Hurley4b293492013-07-24 08:29:55 -04001113static void isig(int sig, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001114{
Peter Hurley8c985d12013-03-06 08:38:19 -05001115 struct pid *tty_pgrp = tty_get_pgrp(tty);
1116 if (tty_pgrp) {
1117 kill_pgrp(tty_pgrp, sig, 1);
1118 put_pid(tty_pgrp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119 }
1120}
1121
1122/**
1123 * n_tty_receive_break - handle break
1124 * @tty: terminal
1125 *
1126 * An RS232 break event has been hit in the incoming bitstream. This
1127 * can cause a variety of events depending upon the termios settings.
1128 *
Peter Hurley6d76bd22013-06-15 09:14:26 -04001129 * n_tty_receive_buf()/producer path:
1130 * caller holds non-exclusive termios_rwsem
1131 * publishes read_head via put_tty_queue()
1132 *
1133 * Note: may get exclusive termios_rwsem if flushing input buffer
Linus Torvalds1da177e2005-04-16 15:20:36 -07001134 */
Alan Cox4edf1822008-02-08 04:18:44 -08001135
Peter Hurley4b293492013-07-24 08:29:55 -04001136static void n_tty_receive_break(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137{
Jiri Slaby57c94122012-10-18 22:26:43 +02001138 struct n_tty_data *ldata = tty->disc_data;
1139
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140 if (I_IGNBRK(tty))
1141 return;
1142 if (I_BRKINT(tty)) {
Peter Hurley8c985d12013-03-06 08:38:19 -05001143 isig(SIGINT, tty);
1144 if (!L_NOFLSH(tty)) {
Peter Hurley6d76bd22013-06-15 09:14:26 -04001145 /* flushing needs exclusive termios_rwsem */
1146 up_read(&tty->termios_rwsem);
Peter Hurley8c985d12013-03-06 08:38:19 -05001147 n_tty_flush_buffer(tty);
1148 tty_driver_flush_buffer(tty);
Peter Hurley6d76bd22013-06-15 09:14:26 -04001149 down_read(&tty->termios_rwsem);
Peter Hurley8c985d12013-03-06 08:38:19 -05001150 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 return;
1152 }
1153 if (I_PARMRK(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001154 put_tty_queue('\377', ldata);
1155 put_tty_queue('\0', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001156 }
Jiri Slaby57c94122012-10-18 22:26:43 +02001157 put_tty_queue('\0', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001158 wake_up_interruptible(&tty->read_wait);
1159}
1160
1161/**
1162 * n_tty_receive_overrun - handle overrun reporting
1163 * @tty: terminal
1164 *
1165 * Data arrived faster than we could process it. While the tty
1166 * driver has flagged this the bits that were missed are gone
1167 * forever.
1168 *
1169 * Called from the receive_buf path so single threaded. Does not
1170 * need locking as num_overrun and overrun_time are function
1171 * private.
1172 */
Alan Cox4edf1822008-02-08 04:18:44 -08001173
Peter Hurley4b293492013-07-24 08:29:55 -04001174static void n_tty_receive_overrun(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001176 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 char buf[64];
1178
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001179 ldata->num_overrun++;
1180 if (time_after(jiffies, ldata->overrun_time + HZ) ||
1181 time_after(ldata->overrun_time, jiffies)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 printk(KERN_WARNING "%s: %d input overrun(s)\n",
1183 tty_name(tty, buf),
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001184 ldata->num_overrun);
1185 ldata->overrun_time = jiffies;
1186 ldata->num_overrun = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 }
1188}
1189
1190/**
1191 * n_tty_receive_parity_error - error notifier
1192 * @tty: terminal device
1193 * @c: character
1194 *
1195 * Process a parity error and queue the right data to indicate
Peter Hurley6d76bd22013-06-15 09:14:26 -04001196 * the error case if necessary.
1197 *
1198 * n_tty_receive_buf()/producer path:
1199 * caller holds non-exclusive termios_rwsem
1200 * publishes read_head via put_tty_queue()
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 */
Peter Hurley4b293492013-07-24 08:29:55 -04001202static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203{
Jiri Slaby57c94122012-10-18 22:26:43 +02001204 struct n_tty_data *ldata = tty->disc_data;
1205
Alan Cox4edf1822008-02-08 04:18:44 -08001206 if (I_IGNPAR(tty))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001208 if (I_PARMRK(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001209 put_tty_queue('\377', ldata);
1210 put_tty_queue('\0', ldata);
1211 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212 } else if (I_INPCK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001213 put_tty_queue('\0', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214 else
Jiri Slaby57c94122012-10-18 22:26:43 +02001215 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216 wake_up_interruptible(&tty->read_wait);
1217}
1218
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001219static void
1220n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c)
1221{
1222 if (!L_NOFLSH(tty)) {
1223 /* flushing needs exclusive termios_rwsem */
1224 up_read(&tty->termios_rwsem);
1225 n_tty_flush_buffer(tty);
1226 tty_driver_flush_buffer(tty);
1227 down_read(&tty->termios_rwsem);
1228 }
1229 if (I_IXON(tty))
1230 start_tty(tty);
1231 if (L_ECHO(tty)) {
1232 echo_char(c, tty);
1233 commit_echoes(tty);
1234 }
1235 isig(signal, tty);
1236 return;
1237}
1238
Linus Torvalds1da177e2005-04-16 15:20:36 -07001239/**
1240 * n_tty_receive_char - perform processing
1241 * @tty: terminal device
1242 * @c: character
1243 *
1244 * Process an individual character of input received from the driver.
Alan Cox4edf1822008-02-08 04:18:44 -08001245 * This is serialized with respect to itself by the rules for the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246 * driver above.
Peter Hurley6d76bd22013-06-15 09:14:26 -04001247 *
1248 * n_tty_receive_buf()/producer path:
1249 * caller holds non-exclusive termios_rwsem
1250 * publishes canon_head if canonical mode is active
1251 * otherwise, publishes read_head via put_tty_queue()
Peter Hurleye60d27c2013-07-24 08:29:56 -04001252 *
1253 * Returns 1 if LNEXT was received, else returns 0
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 */
1255
Peter Hurleye60d27c2013-07-24 08:29:56 -04001256static int
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001257n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001258{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001259 struct n_tty_data *ldata = tty->disc_data;
Joe Petersonacc71bb2009-01-02 13:43:32 +00001260 int parmrk;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 if (I_IXON(tty)) {
1263 if (c == START_CHAR(tty)) {
1264 start_tty(tty);
Peter Hurley17bd7902013-06-15 10:04:24 -04001265 commit_echoes(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001266 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 }
1268 if (c == STOP_CHAR(tty)) {
1269 stop_tty(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001270 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 }
1272 }
Joe Peterson575537b32008-04-30 00:53:30 -07001273
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274 if (L_ISIG(tty)) {
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001275 if (c == INTR_CHAR(tty)) {
1276 n_tty_receive_signal_char(tty, SIGINT, c);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001277 return 0;
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001278 } else if (c == QUIT_CHAR(tty)) {
1279 n_tty_receive_signal_char(tty, SIGQUIT, c);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001280 return 0;
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001281 } else if (c == SUSP_CHAR(tty)) {
1282 n_tty_receive_signal_char(tty, SIGTSTP, c);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001283 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284 }
1285 }
Joe Peterson575537b32008-04-30 00:53:30 -07001286
Peter Hurley855df3c2013-07-24 08:29:50 -04001287 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
1288 start_tty(tty);
1289 process_echoes(tty);
1290 }
1291
Joe Peterson575537b32008-04-30 00:53:30 -07001292 if (c == '\r') {
1293 if (I_IGNCR(tty))
Peter Hurleye60d27c2013-07-24 08:29:56 -04001294 return 0;
Joe Peterson575537b32008-04-30 00:53:30 -07001295 if (I_ICRNL(tty))
1296 c = '\n';
1297 } else if (c == '\n' && I_INLCR(tty))
1298 c = '\r';
1299
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001300 if (ldata->icanon) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001301 if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
1302 (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
1303 eraser(c, tty);
Peter Hurley17bd7902013-06-15 10:04:24 -04001304 commit_echoes(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001305 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001306 }
1307 if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001308 ldata->lnext = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309 if (L_ECHO(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001310 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 if (L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001312 echo_char_raw('^', ldata);
1313 echo_char_raw('\b', ldata);
Peter Hurley17bd7902013-06-15 10:04:24 -04001314 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315 }
1316 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001317 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001319 if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001320 size_t tail = ldata->canon_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321
Jiri Slaby57c94122012-10-18 22:26:43 +02001322 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001323 echo_char(c, tty);
Jiri Slaby57c94122012-10-18 22:26:43 +02001324 echo_char_raw('\n', ldata);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001325 while (tail != ldata->read_head) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001326 echo_char(read_buf(ldata, tail), tty);
1327 tail++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 }
Peter Hurley17bd7902013-06-15 10:04:24 -04001329 commit_echoes(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001330 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331 }
1332 if (c == '\n') {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001333 if (L_ECHO(tty) || L_ECHONL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001334 echo_char_raw('\n', ldata);
Peter Hurley17bd7902013-06-15 10:04:24 -04001335 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336 }
1337 goto handle_newline;
1338 }
1339 if (c == EOF_CHAR(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 c = __DISABLED_CHAR;
1341 goto handle_newline;
1342 }
1343 if ((c == EOL_CHAR(tty)) ||
1344 (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001345 parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty))
1346 ? 1 : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347 /*
1348 * XXX are EOL_CHAR and EOL2_CHAR echoed?!?
1349 */
1350 if (L_ECHO(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 /* Record the column of first canon char. */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001352 if (ldata->canon_head == ldata->read_head)
Jiri Slaby57c94122012-10-18 22:26:43 +02001353 echo_set_canon_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354 echo_char(c, tty);
Peter Hurley17bd7902013-06-15 10:04:24 -04001355 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356 }
1357 /*
1358 * XXX does PARMRK doubling happen for
1359 * EOL_CHAR and EOL2_CHAR?
1360 */
Joe Petersonacc71bb2009-01-02 13:43:32 +00001361 if (parmrk)
Jiri Slaby57c94122012-10-18 22:26:43 +02001362 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001363
Alan Cox4edf1822008-02-08 04:18:44 -08001364handle_newline:
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001365 set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags);
Peter Hurley6d76bd22013-06-15 09:14:26 -04001366 put_tty_queue(c, ldata);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001367 ldata->canon_head = ldata->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
1369 if (waitqueue_active(&tty->read_wait))
1370 wake_up_interruptible(&tty->read_wait);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001371 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372 }
1373 }
Alan Cox4edf1822008-02-08 04:18:44 -08001374
Joe Petersonacc71bb2009-01-02 13:43:32 +00001375 parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
Joe Petersonacc71bb2009-01-02 13:43:32 +00001376 if (L_ECHO(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001377 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001378 if (c == '\n')
Jiri Slaby57c94122012-10-18 22:26:43 +02001379 echo_char_raw('\n', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001380 else {
1381 /* Record the column of first canon char. */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001382 if (ldata->canon_head == ldata->read_head)
Jiri Slaby57c94122012-10-18 22:26:43 +02001383 echo_set_canon_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384 echo_char(c, tty);
1385 }
Peter Hurley17bd7902013-06-15 10:04:24 -04001386 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387 }
1388
Joe Petersonacc71bb2009-01-02 13:43:32 +00001389 if (parmrk)
Jiri Slaby57c94122012-10-18 22:26:43 +02001390 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391
Jiri Slaby57c94122012-10-18 22:26:43 +02001392 put_tty_queue(c, ldata);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001393 return 0;
Alan Cox4edf1822008-02-08 04:18:44 -08001394}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001395
Peter Hurleye60d27c2013-07-24 08:29:56 -04001396static inline void
1397n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c)
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001398{
1399 struct n_tty_data *ldata = tty->disc_data;
1400 int parmrk;
1401
Peter Hurleye60d27c2013-07-24 08:29:56 -04001402 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
1403 start_tty(tty);
1404 process_echoes(tty);
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001405 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001406 if (L_ECHO(tty)) {
1407 finish_erasing(ldata);
1408 /* Record the column of first canon char. */
1409 if (ldata->canon_head == ldata->read_head)
1410 echo_set_canon_col(ldata);
1411 echo_char(c, tty);
1412 commit_echoes(tty);
1413 }
1414 parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
1415 if (parmrk)
1416 put_tty_queue(c, ldata);
1417 put_tty_queue(c, ldata);
1418}
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001419
Peter Hurleye60d27c2013-07-24 08:29:56 -04001420static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
1421{
1422 n_tty_receive_char_inline(tty, c);
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001423}
1424
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001425static inline void
Peter Hurley7de971b2013-07-24 08:29:53 -04001426n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c)
1427{
1428 struct n_tty_data *ldata = tty->disc_data;
1429
Peter Hurleye60d27c2013-07-24 08:29:56 -04001430 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
1431 start_tty(tty);
1432 process_echoes(tty);
Peter Hurley7de971b2013-07-24 08:29:53 -04001433 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001434 if (L_ECHO(tty)) {
1435 finish_erasing(ldata);
1436 /* Record the column of first canon char. */
1437 if (ldata->canon_head == ldata->read_head)
1438 echo_set_canon_col(ldata);
1439 echo_char(c, tty);
1440 commit_echoes(tty);
1441 }
1442 put_tty_queue(c, ldata);
Peter Hurley7de971b2013-07-24 08:29:53 -04001443}
1444
1445static inline void
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001446n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c)
1447{
1448 if (I_ISTRIP(tty))
1449 c &= 0x7f;
1450 if (I_IUCLC(tty) && L_IEXTEN(tty))
1451 c = tolower(c);
1452
1453 if (I_IXON(tty)) {
1454 if (c == STOP_CHAR(tty))
1455 stop_tty(tty);
1456 else if (c == START_CHAR(tty) ||
1457 (tty->stopped && !tty->flow_stopped && I_IXANY(tty) &&
1458 c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) &&
1459 c != SUSP_CHAR(tty))) {
1460 start_tty(tty);
1461 process_echoes(tty);
1462 }
1463 }
1464}
1465
Peter Hurleyd2f8d7a2013-06-15 10:21:24 -04001466static void
1467n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag)
1468{
1469 char buf[64];
1470
1471 switch (flag) {
1472 case TTY_BREAK:
1473 n_tty_receive_break(tty);
1474 break;
1475 case TTY_PARITY:
1476 case TTY_FRAME:
1477 n_tty_receive_parity_error(tty, c);
1478 break;
1479 case TTY_OVERRUN:
1480 n_tty_receive_overrun(tty);
1481 break;
1482 default:
1483 printk(KERN_ERR "%s: unknown flag %d\n",
1484 tty_name(tty, buf), flag);
1485 break;
1486 }
1487}
1488
Peter Hurleye60d27c2013-07-24 08:29:56 -04001489static void
1490n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag)
1491{
1492 struct n_tty_data *ldata = tty->disc_data;
1493
1494 ldata->lnext = 0;
1495 if (likely(flag == TTY_NORMAL)) {
1496 if (I_ISTRIP(tty))
1497 c &= 0x7f;
1498 if (I_IUCLC(tty) && L_IEXTEN(tty))
1499 c = tolower(c);
1500 n_tty_receive_char(tty, c);
1501 } else
1502 n_tty_receive_char_flagged(tty, c, flag);
1503}
1504
Linus Torvalds1da177e2005-04-16 15:20:36 -07001505/**
1506 * n_tty_receive_buf - data receive
1507 * @tty: terminal device
1508 * @cp: buffer
1509 * @fp: flag buffer
1510 * @count: characters
1511 *
1512 * Called by the terminal driver when a block of characters has
1513 * been received. This function must be called from soft contexts
1514 * not from interrupt context. The driver is responsible for making
1515 * calls one at a time and in order (or using flush_to_ldisc)
Peter Hurley6d76bd22013-06-15 09:14:26 -04001516 *
1517 * n_tty_receive_buf()/producer path:
1518 * claims non-exclusive termios_rwsem
1519 * publishes read_head and canon_head
Linus Torvalds1da177e2005-04-16 15:20:36 -07001520 */
Alan Cox4edf1822008-02-08 04:18:44 -08001521
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001522static void
1523n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp,
1524 char *fp, int count)
1525{
1526 struct n_tty_data *ldata = tty->disc_data;
1527 size_t n, head;
1528
1529 head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
1530 n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head);
1531 n = min_t(size_t, count, n);
1532 memcpy(read_buf_addr(ldata, head), cp, n);
1533 ldata->read_head += n;
1534 cp += n;
1535 count -= n;
1536
1537 head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
1538 n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head);
1539 n = min_t(size_t, count, n);
1540 memcpy(read_buf_addr(ldata, head), cp, n);
1541 ldata->read_head += n;
1542}
1543
Peter Hurley554117bd2013-06-15 10:21:25 -04001544static void
1545n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp,
1546 char *fp, int count)
1547{
1548 struct n_tty_data *ldata = tty->disc_data;
1549 char flag = TTY_NORMAL;
1550
1551 while (count--) {
1552 if (fp)
1553 flag = *fp++;
1554 if (likely(flag == TTY_NORMAL))
1555 put_tty_queue(*cp++, ldata);
1556 else
1557 n_tty_receive_char_flagged(tty, *cp++, flag);
1558 }
1559}
1560
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001561static void
1562n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp,
1563 char *fp, int count)
1564{
1565 char flag = TTY_NORMAL;
1566
1567 while (count--) {
1568 if (fp)
1569 flag = *fp++;
1570 if (likely(flag == TTY_NORMAL))
1571 n_tty_receive_char_closing(tty, *cp++);
1572 else
1573 n_tty_receive_char_flagged(tty, *cp++, flag);
1574 }
1575}
1576
Peter Hurley7d88d632013-07-24 08:29:49 -04001577static void
1578n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp,
Peter Hurley6baad002013-07-24 08:29:52 -04001579 char *fp, int count)
1580{
1581 struct n_tty_data *ldata = tty->disc_data;
1582 char flag = TTY_NORMAL;
1583
1584 while (count--) {
1585 if (fp)
1586 flag = *fp++;
1587 if (likely(flag == TTY_NORMAL)) {
1588 unsigned char c = *cp++;
1589
1590 if (I_ISTRIP(tty))
1591 c &= 0x7f;
1592 if (I_IUCLC(tty) && L_IEXTEN(tty))
1593 c = tolower(c);
1594 if (L_EXTPROC(tty)) {
1595 put_tty_queue(c, ldata);
1596 continue;
1597 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001598 if (!test_bit(c, ldata->char_map))
1599 n_tty_receive_char_inline(tty, c);
1600 else if (n_tty_receive_char_special(tty, c) && count) {
1601 if (fp)
1602 flag = *fp++;
1603 n_tty_receive_char_lnext(tty, *cp++, flag);
1604 count--;
1605 }
Peter Hurley6baad002013-07-24 08:29:52 -04001606 } else
1607 n_tty_receive_char_flagged(tty, *cp++, flag);
1608 }
1609}
1610
1611static void
1612n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp,
1613 char *fp, int count)
Peter Hurley7d88d632013-07-24 08:29:49 -04001614{
Peter Hurleye60d27c2013-07-24 08:29:56 -04001615 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley7d88d632013-07-24 08:29:49 -04001616 char flag = TTY_NORMAL;
1617
1618 while (count--) {
1619 if (fp)
1620 flag = *fp++;
Peter Hurleye60d27c2013-07-24 08:29:56 -04001621 if (likely(flag == TTY_NORMAL)) {
1622 unsigned char c = *cp++;
1623
1624 if (!test_bit(c, ldata->char_map))
1625 n_tty_receive_char_fast(tty, c);
1626 else if (n_tty_receive_char_special(tty, c) && count) {
1627 if (fp)
1628 flag = *fp++;
1629 n_tty_receive_char_lnext(tty, *cp++, flag);
1630 count--;
1631 }
1632 } else
Peter Hurley7d88d632013-07-24 08:29:49 -04001633 n_tty_receive_char_flagged(tty, *cp++, flag);
1634 }
1635}
1636
Peter Hurley24a89d12013-06-15 09:14:15 -04001637static void __receive_buf(struct tty_struct *tty, const unsigned char *cp,
1638 char *fp, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001639{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001640 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleya1dd30e2013-06-15 10:21:26 -04001641 bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001642
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001643 if (ldata->real_raw)
1644 n_tty_receive_buf_real_raw(tty, cp, fp, count);
Peter Hurleya1dd30e2013-06-15 10:21:26 -04001645 else if (ldata->raw || (L_EXTPROC(tty) && !preops))
Peter Hurley554117bd2013-06-15 10:21:25 -04001646 n_tty_receive_buf_raw(tty, cp, fp, count);
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001647 else if (tty->closing && !L_EXTPROC(tty))
1648 n_tty_receive_buf_closing(tty, cp, fp, count);
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001649 else {
Peter Hurleye60d27c2013-07-24 08:29:56 -04001650 if (ldata->lnext) {
1651 char flag = TTY_NORMAL;
1652
1653 if (fp)
1654 flag = *fp++;
1655 n_tty_receive_char_lnext(tty, *cp++, flag);
1656 count--;
1657 }
1658
Peter Hurley7de971b2013-07-24 08:29:53 -04001659 if (!preops && !I_PARMRK(tty))
Peter Hurley6baad002013-07-24 08:29:52 -04001660 n_tty_receive_buf_fast(tty, cp, fp, count);
1661 else
1662 n_tty_receive_buf_standard(tty, cp, fp, count);
Peter Hurleycbfd0342013-06-15 10:04:26 -04001663
1664 flush_echoes(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001665 if (tty->ops->flush_chars)
1666 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001667 }
1668
Peter Hurleyce741172013-06-15 09:14:20 -04001669 if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) ||
hyc@symas.com26df6d12010-06-22 10:14:49 -07001670 L_EXTPROC(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001671 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
1672 if (waitqueue_active(&tty->read_wait))
1673 wake_up_interruptible(&tty->read_wait);
1674 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001675}
1676
Peter Hurley24a89d12013-06-15 09:14:15 -04001677static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1678 char *fp, int count)
1679{
Peter Hurley19e2ad62013-07-24 08:29:54 -04001680 int room, n;
1681
Peter Hurley9356b532013-06-15 09:14:24 -04001682 down_read(&tty->termios_rwsem);
Peter Hurley19e2ad62013-07-24 08:29:54 -04001683
1684 while (1) {
1685 room = receive_room(tty);
1686 n = min(count, room);
1687 if (!n)
1688 break;
1689 __receive_buf(tty, cp, fp, n);
1690 cp += n;
1691 if (fp)
1692 fp += n;
1693 count -= n;
1694 }
1695
1696 tty->receive_room = room;
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001697 n_tty_check_throttle(tty);
Peter Hurley9356b532013-06-15 09:14:24 -04001698 up_read(&tty->termios_rwsem);
Peter Hurley24a89d12013-06-15 09:14:15 -04001699}
1700
1701static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp,
1702 char *fp, int count)
1703{
1704 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley19e2ad62013-07-24 08:29:54 -04001705 int room, n, rcvd = 0;
Peter Hurley24a89d12013-06-15 09:14:15 -04001706
Peter Hurley9356b532013-06-15 09:14:24 -04001707 down_read(&tty->termios_rwsem);
1708
Peter Hurley19e2ad62013-07-24 08:29:54 -04001709 while (1) {
1710 room = receive_room(tty);
1711 n = min(count, room);
1712 if (!n) {
1713 if (!room)
1714 ldata->no_room = 1;
1715 break;
1716 }
1717 __receive_buf(tty, cp, fp, n);
1718 cp += n;
1719 if (fp)
1720 fp += n;
1721 count -= n;
1722 rcvd += n;
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001723 }
Peter Hurley24a89d12013-06-15 09:14:15 -04001724
Peter Hurley19e2ad62013-07-24 08:29:54 -04001725 tty->receive_room = room;
1726 n_tty_check_throttle(tty);
Peter Hurley9356b532013-06-15 09:14:24 -04001727 up_read(&tty->termios_rwsem);
1728
Peter Hurley19e2ad62013-07-24 08:29:54 -04001729 return rcvd;
Peter Hurley24a89d12013-06-15 09:14:15 -04001730}
1731
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732int is_ignored(int sig)
1733{
1734 return (sigismember(&current->blocked, sig) ||
Alan Cox4edf1822008-02-08 04:18:44 -08001735 current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001736}
1737
1738/**
1739 * n_tty_set_termios - termios data changed
1740 * @tty: terminal
1741 * @old: previous data
1742 *
1743 * Called by the tty layer when the user changes termios flags so
1744 * that the line discipline can plan ahead. This function cannot sleep
Alan Cox4edf1822008-02-08 04:18:44 -08001745 * and is protected from re-entry by the tty layer. The user is
Linus Torvalds1da177e2005-04-16 15:20:36 -07001746 * guaranteed that this function will not be re-entered or in progress
1747 * when the ldisc is closed.
Alan Cox17b82062008-10-13 10:45:06 +01001748 *
Peter Hurley6a1c0682013-06-15 09:14:23 -04001749 * Locking: Caller holds tty->termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001750 */
Alan Cox4edf1822008-02-08 04:18:44 -08001751
1752static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001754 struct n_tty_data *ldata = tty->disc_data;
Alan Cox47afa7a2008-10-13 10:44:17 +01001755
Peter Hurleyc786f742013-09-17 12:53:35 -04001756 if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) {
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001757 bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
Peter Hurley93a8d412013-09-17 12:34:14 -04001758 ldata->line_start = ldata->canon_head = ldata->read_tail;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001759 ldata->erasing = 0;
Peter Hurley6f9b0282013-06-15 09:14:27 -04001760 ldata->lnext = 0;
Alan Cox47afa7a2008-10-13 10:44:17 +01001761 }
1762
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001763 ldata->icanon = (L_ICANON(tty) != 0);
Peter Hurley582f5592013-05-17 12:49:48 -04001764
Linus Torvalds1da177e2005-04-16 15:20:36 -07001765 if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
1766 I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
1767 I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
1768 I_PARMRK(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001769 bitmap_zero(ldata->char_map, 256);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001770
1771 if (I_IGNCR(tty) || I_ICRNL(tty))
Peter Hurley1bb9d562013-06-15 10:21:20 -04001772 set_bit('\r', ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 if (I_INLCR(tty))
Peter Hurley1bb9d562013-06-15 10:21:20 -04001774 set_bit('\n', ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775
1776 if (L_ICANON(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001777 set_bit(ERASE_CHAR(tty), ldata->char_map);
1778 set_bit(KILL_CHAR(tty), ldata->char_map);
1779 set_bit(EOF_CHAR(tty), ldata->char_map);
1780 set_bit('\n', ldata->char_map);
1781 set_bit(EOL_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001782 if (L_IEXTEN(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001783 set_bit(WERASE_CHAR(tty), ldata->char_map);
1784 set_bit(LNEXT_CHAR(tty), ldata->char_map);
1785 set_bit(EOL2_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786 if (L_ECHO(tty))
1787 set_bit(REPRINT_CHAR(tty),
Peter Hurley1bb9d562013-06-15 10:21:20 -04001788 ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789 }
1790 }
1791 if (I_IXON(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001792 set_bit(START_CHAR(tty), ldata->char_map);
1793 set_bit(STOP_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001794 }
1795 if (L_ISIG(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001796 set_bit(INTR_CHAR(tty), ldata->char_map);
1797 set_bit(QUIT_CHAR(tty), ldata->char_map);
1798 set_bit(SUSP_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 }
Peter Hurley1bb9d562013-06-15 10:21:20 -04001800 clear_bit(__DISABLED_CHAR, ldata->char_map);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001801 ldata->raw = 0;
1802 ldata->real_raw = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001803 } else {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001804 ldata->raw = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001805 if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
1806 (I_IGNPAR(tty) || !I_INPCK(tty)) &&
1807 (tty->driver->flags & TTY_DRIVER_REAL_RAW))
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001808 ldata->real_raw = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809 else
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001810 ldata->real_raw = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001811 }
Linus Torvalds55db4c62011-06-04 06:33:24 +09001812 n_tty_set_room(tty);
Wang YanQingdab73b42013-05-09 14:16:47 +08001813 /*
1814 * Fix tty hang when I_IXON(tty) is cleared, but the tty
1815 * been stopped by STOP_CHAR(tty) before it.
1816 */
Peter Hurley103fcbe22013-09-17 12:53:36 -04001817 if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped)
Wang YanQingdab73b42013-05-09 14:16:47 +08001818 start_tty(tty);
Wang YanQingdab73b42013-05-09 14:16:47 +08001819
Alan Coxf34d7a52008-04-30 00:54:13 -07001820 /* The termios change make the tty ready for I/O */
1821 wake_up_interruptible(&tty->write_wait);
1822 wake_up_interruptible(&tty->read_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001823}
1824
1825/**
1826 * n_tty_close - close the ldisc for this tty
1827 * @tty: device
1828 *
Alan Cox4edf1822008-02-08 04:18:44 -08001829 * Called from the terminal layer when this line discipline is
1830 * being shut down, either because of a close or becsuse of a
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831 * discipline change. The function will not be called while other
1832 * ldisc methods are in progress.
1833 */
Alan Cox4edf1822008-02-08 04:18:44 -08001834
Linus Torvalds1da177e2005-04-16 15:20:36 -07001835static void n_tty_close(struct tty_struct *tty)
1836{
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001837 struct n_tty_data *ldata = tty->disc_data;
1838
Peter Hurley79901312013-03-11 16:44:23 -04001839 if (tty->link)
1840 n_tty_packet_mode_flush(tty);
1841
Peter Hurley20bafb32013-06-15 10:21:19 -04001842 vfree(ldata);
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001843 tty->disc_data = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001844}
1845
1846/**
1847 * n_tty_open - open an ldisc
1848 * @tty: terminal to open
1849 *
Alan Cox4edf1822008-02-08 04:18:44 -08001850 * Called when this line discipline is being attached to the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851 * terminal device. Can sleep. Called serialized so that no
1852 * other events will occur in parallel. No further open will occur
1853 * until a close.
1854 */
1855
1856static int n_tty_open(struct tty_struct *tty)
1857{
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001858 struct n_tty_data *ldata;
1859
Peter Hurley20bafb32013-06-15 10:21:19 -04001860 /* Currently a malloc failure here can panic */
1861 ldata = vmalloc(sizeof(*ldata));
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001862 if (!ldata)
1863 goto err;
1864
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001865 ldata->overrun_time = jiffies;
Jiri Slabybddc7152012-10-18 22:26:42 +02001866 mutex_init(&ldata->atomic_read_lock);
1867 mutex_init(&ldata->output_lock);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001868
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001869 tty->disc_data = ldata;
Peter Hurleyb66f4fa2013-03-11 16:44:32 -04001870 reset_buffer_flags(tty->disc_data);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001871 ldata->column = 0;
Peter Hurley20bafb32013-06-15 10:21:19 -04001872 ldata->canon_column = 0;
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04001873 ldata->minimum_to_wake = 1;
Peter Hurley20bafb32013-06-15 10:21:19 -04001874 ldata->num_overrun = 0;
1875 ldata->no_room = 0;
1876 ldata->lnext = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877 tty->closing = 0;
Peter Hurleyb66f4fa2013-03-11 16:44:32 -04001878 /* indicate buffer work may resume */
1879 clear_bit(TTY_LDISC_HALTED, &tty->flags);
1880 n_tty_set_termios(tty, NULL);
1881 tty_unthrottle(tty);
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001882
Linus Torvalds1da177e2005-04-16 15:20:36 -07001883 return 0;
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001884err:
Jiri Slabyb91939f2012-10-18 22:26:35 +02001885 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001886}
1887
1888static inline int input_available_p(struct tty_struct *tty, int amt)
1889{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001890 struct n_tty_data *ldata = tty->disc_data;
1891
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001892 if (ldata->icanon && !L_EXTPROC(tty)) {
Peter Hurleya73d3d62013-06-15 09:14:25 -04001893 if (ldata->canon_head != ldata->read_tail)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001894 return 1;
Peter Hurleyce741172013-06-15 09:14:20 -04001895 } else if (read_cnt(ldata) >= (amt ? amt : 1))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001896 return 1;
1897
1898 return 0;
1899}
1900
1901/**
Thorsten Wißmannbbd20752011-12-08 17:47:33 +01001902 * copy_from_read_buf - copy read data directly
Linus Torvalds1da177e2005-04-16 15:20:36 -07001903 * @tty: terminal device
1904 * @b: user data
1905 * @nr: size of data
1906 *
Alan Cox11a96d12008-10-13 10:46:24 +01001907 * Helper function to speed up n_tty_read. It is only called when
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908 * ICANON is off; it copies characters straight from the tty queue to
1909 * user space directly. It can be profitably called twice; once to
1910 * drain the space from the tail pointer to the (physical) end of the
1911 * buffer, and once to drain the space from the (physical) beginning of
1912 * the buffer to head pointer.
1913 *
Jiri Slabybddc7152012-10-18 22:26:42 +02001914 * Called under the ldata->atomic_read_lock sem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001915 *
Peter Hurley6d76bd22013-06-15 09:14:26 -04001916 * n_tty_read()/consumer path:
1917 * caller holds non-exclusive termios_rwsem
1918 * read_tail published
Linus Torvalds1da177e2005-04-16 15:20:36 -07001919 */
Alan Cox4edf1822008-02-08 04:18:44 -08001920
Alan Cox33f0f882006-01-09 20:54:13 -08001921static int copy_from_read_buf(struct tty_struct *tty,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922 unsigned char __user **b,
1923 size_t *nr)
1924
1925{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001926 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001927 int retval;
1928 size_t n;
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02001929 bool is_eof;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001930 size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001931
1932 retval = 0;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001933 n = min(read_cnt(ldata), N_TTY_BUF_SIZE - tail);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001934 n = min(*nr, n);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001935 if (n) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001936 retval = copy_to_user(*b, read_buf_addr(ldata, tail), n);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001937 n -= retval;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001938 is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty);
1939 tty_audit_add_data(tty, read_buf_addr(ldata, tail), n,
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001940 ldata->icanon);
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001941 ldata->read_tail += n;
hyc@symas.com26df6d12010-06-22 10:14:49 -07001942 /* Turn single EOF into zero-length read */
Peter Hurleyce741172013-06-15 09:14:20 -04001943 if (L_EXTPROC(tty) && ldata->icanon && is_eof && !read_cnt(ldata))
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02001944 n = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001945 *b += n;
1946 *nr -= n;
1947 }
1948 return retval;
1949}
1950
Peter Hurley88bb0de2013-06-15 09:14:16 -04001951/**
Peter Hurley32f13522013-06-15 09:14:17 -04001952 * canon_copy_from_read_buf - copy read data in canonical mode
Peter Hurley88bb0de2013-06-15 09:14:16 -04001953 * @tty: terminal device
1954 * @b: user data
1955 * @nr: size of data
1956 *
1957 * Helper function for n_tty_read. It is only called when ICANON is on;
Peter Hurley32f13522013-06-15 09:14:17 -04001958 * it copies one line of input up to and including the line-delimiting
1959 * character into the user-space buffer.
Peter Hurley88bb0de2013-06-15 09:14:16 -04001960 *
1961 * Called under the atomic_read_lock mutex
Peter Hurley6d76bd22013-06-15 09:14:26 -04001962 *
1963 * n_tty_read()/consumer path:
1964 * caller holds non-exclusive termios_rwsem
1965 * read_tail published
Peter Hurley88bb0de2013-06-15 09:14:16 -04001966 */
1967
Peter Hurley32f13522013-06-15 09:14:17 -04001968static int canon_copy_from_read_buf(struct tty_struct *tty,
1969 unsigned char __user **b,
1970 size_t *nr)
Peter Hurley88bb0de2013-06-15 09:14:16 -04001971{
1972 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley32f13522013-06-15 09:14:17 -04001973 size_t n, size, more, c;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001974 size_t eol;
1975 size_t tail;
1976 int ret, found = 0;
Peter Hurley40d5e092013-06-15 10:21:17 -04001977 bool eof_push = 0;
Peter Hurley88bb0de2013-06-15 09:14:16 -04001978
1979 /* N.B. avoid overrun if nr == 0 */
Peter Hurleyce741172013-06-15 09:14:20 -04001980 n = min(*nr, read_cnt(ldata));
Peter Hurley6d76bd22013-06-15 09:14:26 -04001981 if (!n)
Peter Hurley32f13522013-06-15 09:14:17 -04001982 return 0;
Peter Hurley88bb0de2013-06-15 09:14:16 -04001983
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001984 tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
Peter Hurley32f13522013-06-15 09:14:17 -04001985 size = min_t(size_t, tail + n, N_TTY_BUF_SIZE);
1986
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001987 n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n",
Peter Hurley32f13522013-06-15 09:14:17 -04001988 __func__, *nr, tail, n, size);
1989
1990 eol = find_next_bit(ldata->read_flags, size, tail);
1991 more = n - (size - tail);
1992 if (eol == N_TTY_BUF_SIZE && more) {
1993 /* scan wrapped without finding set bit */
1994 eol = find_next_bit(ldata->read_flags, more, 0);
1995 if (eol != more)
1996 found = 1;
1997 } else if (eol != size)
1998 found = 1;
1999
2000 size = N_TTY_BUF_SIZE - tail;
Peter Hurleyc77569d2013-11-22 07:16:25 -05002001 n = eol - tail;
2002 if (n > 4096)
2003 n += 4096;
2004 n += found;
Peter Hurley32f13522013-06-15 09:14:17 -04002005 c = n;
2006
Peter Hurley40d5e092013-06-15 10:21:17 -04002007 if (found && read_buf(ldata, eol) == __DISABLED_CHAR) {
Peter Hurley32f13522013-06-15 09:14:17 -04002008 n--;
Peter Hurley40d5e092013-06-15 10:21:17 -04002009 eof_push = !n && ldata->read_tail != ldata->line_start;
2010 }
Peter Hurley32f13522013-06-15 09:14:17 -04002011
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002012 n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n",
Peter Hurley32f13522013-06-15 09:14:17 -04002013 __func__, eol, found, n, c, size, more);
2014
Peter Hurley32f13522013-06-15 09:14:17 -04002015 if (n > size) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002016 ret = copy_to_user(*b, read_buf_addr(ldata, tail), size);
Peter Hurley32f13522013-06-15 09:14:17 -04002017 if (ret)
2018 return -EFAULT;
2019 ret = copy_to_user(*b + size, ldata->read_buf, n - size);
2020 } else
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002021 ret = copy_to_user(*b, read_buf_addr(ldata, tail), n);
Peter Hurley32f13522013-06-15 09:14:17 -04002022
2023 if (ret)
2024 return -EFAULT;
2025 *b += n;
2026 *nr -= n;
2027
Peter Hurleya73d3d62013-06-15 09:14:25 -04002028 if (found)
Peter Hurley6d76bd22013-06-15 09:14:26 -04002029 clear_bit(eol, ldata->read_flags);
2030 smp_mb__after_clear_bit();
2031 ldata->read_tail += c;
Peter Hurley88bb0de2013-06-15 09:14:16 -04002032
Peter Hurley40d5e092013-06-15 10:21:17 -04002033 if (found) {
2034 ldata->line_start = ldata->read_tail;
Peter Hurley32f13522013-06-15 09:14:17 -04002035 tty_audit_push(tty);
Peter Hurley40d5e092013-06-15 10:21:17 -04002036 }
2037 return eof_push ? -EAGAIN : 0;
Peter Hurley88bb0de2013-06-15 09:14:16 -04002038}
2039
Al Virocc4191d2008-03-29 03:08:48 +00002040extern ssize_t redirected_tty_write(struct file *, const char __user *,
Alan Cox4edf1822008-02-08 04:18:44 -08002041 size_t, loff_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002042
2043/**
2044 * job_control - check job control
2045 * @tty: tty
2046 * @file: file handle
2047 *
2048 * Perform job control management checks on this file/tty descriptor
Alan Cox4edf1822008-02-08 04:18:44 -08002049 * and if appropriate send any needed signals and return a negative
Linus Torvalds1da177e2005-04-16 15:20:36 -07002050 * error code if action should be taken.
Alan Cox04f378b2008-04-30 00:53:29 -07002051 *
Peter Hurley01a5e442013-03-06 08:38:20 -05002052 * Locking: redirected write test is safe
2053 * current->signal->tty check is safe
2054 * ctrl_lock to safely reference tty->pgrp
Linus Torvalds1da177e2005-04-16 15:20:36 -07002055 */
Alan Cox4edf1822008-02-08 04:18:44 -08002056
Linus Torvalds1da177e2005-04-16 15:20:36 -07002057static int job_control(struct tty_struct *tty, struct file *file)
2058{
2059 /* Job control check -- must be done at start and after
2060 every sleep (POSIX.1 7.1.1.4). */
2061 /* NOTE: not yet done after every sleep pending a thorough
2062 check of the logic of this change. -- jlc */
2063 /* don't stop on /dev/console */
Peter Hurley01a5e442013-03-06 08:38:20 -05002064 if (file->f_op->write == redirected_tty_write ||
2065 current->signal->tty != tty)
2066 return 0;
2067
2068 spin_lock_irq(&tty->ctrl_lock);
2069 if (!tty->pgrp)
2070 printk(KERN_ERR "n_tty_read: no tty->pgrp!\n");
2071 else if (task_pgrp(current) != tty->pgrp) {
2072 spin_unlock_irq(&tty->ctrl_lock);
2073 if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned())
2074 return -EIO;
2075 kill_pgrp(task_pgrp(current), SIGTTIN, 1);
2076 set_thread_flag(TIF_SIGPENDING);
2077 return -ERESTARTSYS;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002078 }
Peter Hurley01a5e442013-03-06 08:38:20 -05002079 spin_unlock_irq(&tty->ctrl_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002080 return 0;
2081}
Alan Cox4edf1822008-02-08 04:18:44 -08002082
Linus Torvalds1da177e2005-04-16 15:20:36 -07002083
2084/**
Alan Cox11a96d12008-10-13 10:46:24 +01002085 * n_tty_read - read function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07002086 * @tty: tty device
2087 * @file: file object
2088 * @buf: userspace buffer pointer
2089 * @nr: size of I/O
2090 *
2091 * Perform reads for the line discipline. We are guaranteed that the
2092 * line discipline will not be closed under us but we may get multiple
2093 * parallel readers and must handle this ourselves. We may also get
2094 * a hangup. Always called in user context, may sleep.
2095 *
2096 * This code must be sure never to sleep through a hangup.
Peter Hurley6d76bd22013-06-15 09:14:26 -04002097 *
2098 * n_tty_read()/consumer path:
2099 * claims non-exclusive termios_rwsem
2100 * publishes read_tail
Linus Torvalds1da177e2005-04-16 15:20:36 -07002101 */
Alan Cox4edf1822008-02-08 04:18:44 -08002102
Alan Cox11a96d12008-10-13 10:46:24 +01002103static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002104 unsigned char __user *buf, size_t nr)
2105{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002106 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002107 unsigned char __user *b = buf;
2108 DECLARE_WAITQUEUE(wait, current);
2109 int c;
2110 int minimum, time;
2111 ssize_t retval = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002112 long timeout;
2113 unsigned long flags;
Alan Cox04f378b2008-04-30 00:53:29 -07002114 int packet;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002115
Linus Torvalds1da177e2005-04-16 15:20:36 -07002116 c = job_control(tty, file);
Alan Cox4edf1822008-02-08 04:18:44 -08002117 if (c < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002118 return c;
Alan Cox4edf1822008-02-08 04:18:44 -08002119
Peter Hurleyaefceaf2013-08-11 08:04:23 -04002120 /*
2121 * Internal serialization of reads.
2122 */
2123 if (file->f_flags & O_NONBLOCK) {
2124 if (!mutex_trylock(&ldata->atomic_read_lock))
2125 return -EAGAIN;
2126 } else {
2127 if (mutex_lock_interruptible(&ldata->atomic_read_lock))
2128 return -ERESTARTSYS;
2129 }
2130
Peter Hurley9356b532013-06-15 09:14:24 -04002131 down_read(&tty->termios_rwsem);
2132
Linus Torvalds1da177e2005-04-16 15:20:36 -07002133 minimum = time = 0;
2134 timeout = MAX_SCHEDULE_TIMEOUT;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002135 if (!ldata->icanon) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002136 minimum = MIN_CHAR(tty);
2137 if (minimum) {
Peter Hurleya6e54312013-06-15 07:28:29 -04002138 time = (HZ / 10) * TIME_CHAR(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002139 if (time)
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002140 ldata->minimum_to_wake = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002141 else if (!waitqueue_active(&tty->read_wait) ||
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002142 (ldata->minimum_to_wake > minimum))
2143 ldata->minimum_to_wake = minimum;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002144 } else {
Peter Hurleya6e54312013-06-15 07:28:29 -04002145 timeout = (HZ / 10) * TIME_CHAR(tty);
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002146 ldata->minimum_to_wake = minimum = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002147 }
2148 }
2149
Alan Cox04f378b2008-04-30 00:53:29 -07002150 packet = tty->packet;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002151
2152 add_wait_queue(&tty->read_wait, &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002153 while (nr) {
2154 /* First test for status change. */
Alan Cox04f378b2008-04-30 00:53:29 -07002155 if (packet && tty->link->ctrl_status) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002156 unsigned char cs;
2157 if (b != buf)
2158 break;
Alan Cox04f378b2008-04-30 00:53:29 -07002159 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002160 cs = tty->link->ctrl_status;
2161 tty->link->ctrl_status = 0;
Alan Cox04f378b2008-04-30 00:53:29 -07002162 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
Miloslav Trmac522ed772007-07-15 23:40:56 -07002163 if (tty_put_user(tty, cs, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002164 retval = -EFAULT;
2165 b--;
2166 break;
2167 }
2168 nr--;
2169 break;
2170 }
2171 /* This statement must be first before checking for input
2172 so that any interrupt will set the state back to
2173 TASK_RUNNING. */
2174 set_current_state(TASK_INTERRUPTIBLE);
Alan Cox4edf1822008-02-08 04:18:44 -08002175
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002176 if (((minimum - (b - buf)) < ldata->minimum_to_wake) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07002177 ((minimum - (b - buf)) >= 1))
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002178 ldata->minimum_to_wake = (minimum - (b - buf));
Alan Cox4edf1822008-02-08 04:18:44 -08002179
Linus Torvalds1da177e2005-04-16 15:20:36 -07002180 if (!input_available_p(tty, 0)) {
2181 if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
Peter Hurleyf8747d42013-09-27 13:27:05 -04002182 up_read(&tty->termios_rwsem);
2183 tty_flush_to_ldisc(tty);
2184 down_read(&tty->termios_rwsem);
2185 if (!input_available_p(tty, 0)) {
2186 retval = -EIO;
2187 break;
2188 }
2189 } else {
2190 if (tty_hung_up_p(file))
2191 break;
2192 if (!timeout)
2193 break;
2194 if (file->f_flags & O_NONBLOCK) {
2195 retval = -EAGAIN;
2196 break;
2197 }
2198 if (signal_pending(current)) {
2199 retval = -ERESTARTSYS;
2200 break;
2201 }
2202 n_tty_set_room(tty);
2203 up_read(&tty->termios_rwsem);
Peter Hurley9356b532013-06-15 09:14:24 -04002204
Peter Hurleyf8747d42013-09-27 13:27:05 -04002205 timeout = schedule_timeout(timeout);
Peter Hurley9356b532013-06-15 09:14:24 -04002206
Peter Hurleyf8747d42013-09-27 13:27:05 -04002207 down_read(&tty->termios_rwsem);
2208 continue;
2209 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002210 }
2211 __set_current_state(TASK_RUNNING);
2212
2213 /* Deal with packet mode. */
Alan Cox04f378b2008-04-30 00:53:29 -07002214 if (packet && b == buf) {
Miloslav Trmac522ed772007-07-15 23:40:56 -07002215 if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002216 retval = -EFAULT;
2217 b--;
2218 break;
2219 }
2220 nr--;
2221 }
2222
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002223 if (ldata->icanon && !L_EXTPROC(tty)) {
Peter Hurley32f13522013-06-15 09:14:17 -04002224 retval = canon_copy_from_read_buf(tty, &b, &nr);
Peter Hurley40d5e092013-06-15 10:21:17 -04002225 if (retval == -EAGAIN) {
2226 retval = 0;
2227 continue;
2228 } else if (retval)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002229 break;
2230 } else {
2231 int uncopied;
Alan Cox04f378b2008-04-30 00:53:29 -07002232 /* The copy function takes the read lock and handles
2233 locking internally for this case */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002234 uncopied = copy_from_read_buf(tty, &b, &nr);
2235 uncopied += copy_from_read_buf(tty, &b, &nr);
2236 if (uncopied) {
2237 retval = -EFAULT;
2238 break;
2239 }
2240 }
2241
Peter Hurley6367ca72013-06-15 09:14:33 -04002242 n_tty_check_unthrottle(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002243
2244 if (b - buf >= minimum)
2245 break;
2246 if (time)
2247 timeout = time;
2248 }
Peter Hurley42458f42013-11-07 13:59:46 -05002249 n_tty_set_room(tty);
2250 up_read(&tty->termios_rwsem);
2251
Jiri Slabybddc7152012-10-18 22:26:42 +02002252 mutex_unlock(&ldata->atomic_read_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002253 remove_wait_queue(&tty->read_wait, &wait);
2254
2255 if (!waitqueue_active(&tty->read_wait))
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002256 ldata->minimum_to_wake = minimum;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002257
2258 __set_current_state(TASK_RUNNING);
Peter Hurley40d5e092013-06-15 10:21:17 -04002259 if (b - buf)
2260 retval = b - buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002261
2262 return retval;
2263}
2264
2265/**
Alan Cox11a96d12008-10-13 10:46:24 +01002266 * n_tty_write - write function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07002267 * @tty: tty device
2268 * @file: file object
2269 * @buf: userspace buffer pointer
2270 * @nr: size of I/O
2271 *
Joe Petersona88a69c2009-01-02 13:40:53 +00002272 * Write function of the terminal device. This is serialized with
Linus Torvalds1da177e2005-04-16 15:20:36 -07002273 * respect to other write callers but not to termios changes, reads
Joe Petersona88a69c2009-01-02 13:40:53 +00002274 * and other such events. Since the receive code will echo characters,
2275 * thus calling driver write methods, the output_lock is used in
2276 * the output processing functions called here as well as in the
2277 * echo processing function to protect the column state and space
2278 * left in the buffer.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002279 *
2280 * This code must be sure never to sleep through a hangup.
Joe Petersona88a69c2009-01-02 13:40:53 +00002281 *
2282 * Locking: output_lock to protect column state and space left
2283 * (note that the process_output*() functions take this
2284 * lock themselves)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002285 */
Alan Cox4edf1822008-02-08 04:18:44 -08002286
Alan Cox11a96d12008-10-13 10:46:24 +01002287static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
Joe Petersona88a69c2009-01-02 13:40:53 +00002288 const unsigned char *buf, size_t nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002289{
2290 const unsigned char *b = buf;
2291 DECLARE_WAITQUEUE(wait, current);
2292 int c;
2293 ssize_t retval = 0;
2294
2295 /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
2296 if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) {
2297 retval = tty_check_change(tty);
2298 if (retval)
2299 return retval;
2300 }
2301
Peter Hurley9356b532013-06-15 09:14:24 -04002302 down_read(&tty->termios_rwsem);
2303
Joe Petersona88a69c2009-01-02 13:40:53 +00002304 /* Write out any echoed characters that are still pending */
2305 process_echoes(tty);
Alan Cox300a6202009-01-02 13:41:04 +00002306
Linus Torvalds1da177e2005-04-16 15:20:36 -07002307 add_wait_queue(&tty->write_wait, &wait);
2308 while (1) {
2309 set_current_state(TASK_INTERRUPTIBLE);
2310 if (signal_pending(current)) {
2311 retval = -ERESTARTSYS;
2312 break;
2313 }
2314 if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) {
2315 retval = -EIO;
2316 break;
2317 }
Peter Hurley582f5592013-05-17 12:49:48 -04002318 if (O_OPOST(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002319 while (nr > 0) {
Joe Petersona88a69c2009-01-02 13:40:53 +00002320 ssize_t num = process_output_block(tty, b, nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002321 if (num < 0) {
2322 if (num == -EAGAIN)
2323 break;
2324 retval = num;
2325 goto break_out;
2326 }
2327 b += num;
2328 nr -= num;
2329 if (nr == 0)
2330 break;
2331 c = *b;
Joe Petersona88a69c2009-01-02 13:40:53 +00002332 if (process_output(c, tty) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002333 break;
2334 b++; nr--;
2335 }
Alan Coxf34d7a52008-04-30 00:54:13 -07002336 if (tty->ops->flush_chars)
2337 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002338 } else {
Roman Zippeld6afe272005-07-07 17:56:55 -07002339 while (nr > 0) {
Alan Coxf34d7a52008-04-30 00:54:13 -07002340 c = tty->ops->write(tty, b, nr);
Roman Zippeld6afe272005-07-07 17:56:55 -07002341 if (c < 0) {
2342 retval = c;
2343 goto break_out;
2344 }
2345 if (!c)
2346 break;
2347 b += c;
2348 nr -= c;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002349 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002350 }
2351 if (!nr)
2352 break;
2353 if (file->f_flags & O_NONBLOCK) {
2354 retval = -EAGAIN;
2355 break;
2356 }
Peter Hurley9356b532013-06-15 09:14:24 -04002357 up_read(&tty->termios_rwsem);
2358
Linus Torvalds1da177e2005-04-16 15:20:36 -07002359 schedule();
Peter Hurley9356b532013-06-15 09:14:24 -04002360
2361 down_read(&tty->termios_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002362 }
2363break_out:
2364 __set_current_state(TASK_RUNNING);
2365 remove_wait_queue(&tty->write_wait, &wait);
Thomas Pfaffff8cb0f2009-01-02 13:47:13 +00002366 if (b - buf != nr && tty->fasync)
2367 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Peter Hurley9356b532013-06-15 09:14:24 -04002368 up_read(&tty->termios_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002369 return (b - buf) ? b - buf : retval;
2370}
2371
2372/**
Alan Cox11a96d12008-10-13 10:46:24 +01002373 * n_tty_poll - poll method for N_TTY
Linus Torvalds1da177e2005-04-16 15:20:36 -07002374 * @tty: terminal device
2375 * @file: file accessing it
2376 * @wait: poll table
2377 *
2378 * Called when the line discipline is asked to poll() for data or
2379 * for special events. This code is not serialized with respect to
2380 * other events save open/close.
2381 *
2382 * This code must be sure never to sleep through a hangup.
2383 * Called without the kernel lock held - fine
Linus Torvalds1da177e2005-04-16 15:20:36 -07002384 */
Alan Cox4edf1822008-02-08 04:18:44 -08002385
Alan Cox11a96d12008-10-13 10:46:24 +01002386static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
Alan Cox4edf1822008-02-08 04:18:44 -08002387 poll_table *wait)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002388{
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002389 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002390 unsigned int mask = 0;
2391
2392 poll_wait(file, &tty->read_wait, wait);
2393 poll_wait(file, &tty->write_wait, wait);
2394 if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty)))
2395 mask |= POLLIN | POLLRDNORM;
2396 if (tty->packet && tty->link->ctrl_status)
2397 mask |= POLLPRI | POLLIN | POLLRDNORM;
2398 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
2399 mask |= POLLHUP;
2400 if (tty_hung_up_p(file))
2401 mask |= POLLHUP;
2402 if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) {
2403 if (MIN_CHAR(tty) && !TIME_CHAR(tty))
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002404 ldata->minimum_to_wake = MIN_CHAR(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002405 else
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002406 ldata->minimum_to_wake = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002407 }
Alan Coxf34d7a52008-04-30 00:54:13 -07002408 if (tty->ops->write && !tty_is_writelocked(tty) &&
2409 tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
2410 tty_write_room(tty) > 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002411 mask |= POLLOUT | POLLWRNORM;
2412 return mask;
2413}
2414
Jiri Slaby57c94122012-10-18 22:26:43 +02002415static unsigned long inq_canon(struct n_tty_data *ldata)
Alan Cox47afa7a2008-10-13 10:44:17 +01002416{
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002417 size_t nr, head, tail;
Alan Cox47afa7a2008-10-13 10:44:17 +01002418
Peter Hurleya73d3d62013-06-15 09:14:25 -04002419 if (ldata->canon_head == ldata->read_tail)
Alan Cox47afa7a2008-10-13 10:44:17 +01002420 return 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002421 head = ldata->canon_head;
2422 tail = ldata->read_tail;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002423 nr = head - tail;
Alan Cox47afa7a2008-10-13 10:44:17 +01002424 /* Skip EOF-chars.. */
2425 while (head != tail) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002426 if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) &&
2427 read_buf(ldata, tail) == __DISABLED_CHAR)
Alan Cox47afa7a2008-10-13 10:44:17 +01002428 nr--;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002429 tail++;
Alan Cox47afa7a2008-10-13 10:44:17 +01002430 }
2431 return nr;
2432}
2433
2434static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
2435 unsigned int cmd, unsigned long arg)
2436{
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002437 struct n_tty_data *ldata = tty->disc_data;
Alan Cox47afa7a2008-10-13 10:44:17 +01002438 int retval;
2439
2440 switch (cmd) {
2441 case TIOCOUTQ:
2442 return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
2443 case TIOCINQ:
Peter Hurley6d76bd22013-06-15 09:14:26 -04002444 down_write(&tty->termios_rwsem);
Alan Cox47afa7a2008-10-13 10:44:17 +01002445 if (L_ICANON(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02002446 retval = inq_canon(ldata);
Peter Hurley6d76bd22013-06-15 09:14:26 -04002447 else
2448 retval = read_cnt(ldata);
2449 up_write(&tty->termios_rwsem);
Alan Cox47afa7a2008-10-13 10:44:17 +01002450 return put_user(retval, (unsigned int __user *) arg);
2451 default:
2452 return n_tty_ioctl_helper(tty, file, cmd, arg);
2453 }
2454}
2455
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002456static void n_tty_fasync(struct tty_struct *tty, int on)
2457{
2458 struct n_tty_data *ldata = tty->disc_data;
2459
2460 if (!waitqueue_active(&tty->read_wait)) {
2461 if (on)
2462 ldata->minimum_to_wake = 1;
2463 else if (!tty->fasync)
2464 ldata->minimum_to_wake = N_TTY_BUF_SIZE;
2465 }
2466}
2467
Alan Coxa352def2008-07-16 21:53:12 +01002468struct tty_ldisc_ops tty_ldisc_N_TTY = {
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002469 .magic = TTY_LDISC_MAGIC,
2470 .name = "n_tty",
2471 .open = n_tty_open,
2472 .close = n_tty_close,
2473 .flush_buffer = n_tty_flush_buffer,
2474 .chars_in_buffer = n_tty_chars_in_buffer,
Alan Cox11a96d12008-10-13 10:46:24 +01002475 .read = n_tty_read,
2476 .write = n_tty_write,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002477 .ioctl = n_tty_ioctl,
2478 .set_termios = n_tty_set_termios,
Alan Cox11a96d12008-10-13 10:46:24 +01002479 .poll = n_tty_poll,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002480 .receive_buf = n_tty_receive_buf,
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002481 .write_wakeup = n_tty_write_wakeup,
2482 .fasync = n_tty_fasync,
Peter Hurley24a89d12013-06-15 09:14:15 -04002483 .receive_buf2 = n_tty_receive_buf2,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002484};
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -08002485
2486/**
2487 * n_tty_inherit_ops - inherit N_TTY methods
2488 * @ops: struct tty_ldisc_ops where to save N_TTY methods
2489 *
George Spelvin593fb1ae42013-02-12 02:00:43 -05002490 * Enables a 'subclass' line discipline to 'inherit' N_TTY
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -08002491 * methods.
2492 */
2493
2494void n_tty_inherit_ops(struct tty_ldisc_ops *ops)
2495{
2496 *ops = tty_ldisc_N_TTY;
2497 ops->owner = NULL;
2498 ops->refcount = ops->flags = 0;
2499}
2500EXPORT_SYMBOL_GPL(n_tty_inherit_ops);