blob: c7f8f7bc14233d3bcaefe4e7496d6f312d8ecaca [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);
Peter Hurley6c677162013-12-02 14:24:46 -0500277 if (waitqueue_active(&tty->link->write_wait))
278 wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT);
Peter Hurley3afb1b392013-07-23 08:47:30 -0400279 return;
280 }
281
Peter Hurley6367ca72013-06-15 09:14:33 -0400282 /* If there is enough space in the read buffer now, let the
283 * low-level driver know. We use chars_in_buffer() to
284 * check the buffer, as it now knows about canonical mode.
285 * Otherwise, if the driver is throttled and the line is
286 * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
287 * we won't get any more characters.
288 */
289
290 while (1) {
291 int unthrottled;
292 tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE);
293 if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
294 break;
295 if (!tty->count)
296 break;
297 n_tty_set_room(tty);
298 unthrottled = tty_unthrottle_safe(tty);
299 if (!unthrottled)
300 break;
301 }
302 __tty_set_flow_change(tty, 0);
303}
304
Alan Cox17b82062008-10-13 10:45:06 +0100305/**
306 * put_tty_queue - add character to tty
307 * @c: character
Jiri Slaby57c94122012-10-18 22:26:43 +0200308 * @ldata: n_tty data
Alan Cox17b82062008-10-13 10:45:06 +0100309 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400310 * Add a character to the tty read_buf queue.
311 *
312 * n_tty_receive_buf()/producer path:
313 * caller holds non-exclusive termios_rwsem
314 * modifies read_head
315 *
316 * read_head is only considered 'published' if canonical mode is
317 * not active.
Alan Cox17b82062008-10-13 10:45:06 +0100318 */
319
Peter Hurley19e2ad62013-07-24 08:29:54 -0400320static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321{
Peter Hurley19e2ad62013-07-24 08:29:54 -0400322 *read_buf_addr(ldata, ldata->read_head++) = c;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323}
324
325/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 * reset_buffer_flags - reset buffer state
327 * @tty: terminal to reset
328 *
Peter Hurley25518c62013-03-11 16:44:31 -0400329 * Reset the read buffer counters and clear the flags.
330 * Called from n_tty_open() and n_tty_flush_buffer().
Alan Cox17b82062008-10-13 10:45:06 +0100331 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400332 * Locking: caller holds exclusive termios_rwsem
333 * (or locking is not required)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000335
Peter Hurleyb66f4fa2013-03-11 16:44:32 -0400336static void reset_buffer_flags(struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337{
Peter Hurleya73d3d62013-06-15 09:14:25 -0400338 ldata->read_head = ldata->canon_head = ldata->read_tail = 0;
Peter Hurley17bd7902013-06-15 10:04:24 -0400339 ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0;
Peter Hurley40d5e092013-06-15 10:21:17 -0400340 ldata->line_start = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000341
Peter Hurleya73d3d62013-06-15 09:14:25 -0400342 ldata->erasing = 0;
Jiri Slaby3fe780b2012-10-18 22:26:40 +0200343 bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344}
345
Peter Hurleya30737a2013-03-11 16:44:22 -0400346static void n_tty_packet_mode_flush(struct tty_struct *tty)
347{
348 unsigned long flags;
349
350 spin_lock_irqsave(&tty->ctrl_lock, flags);
351 if (tty->link->packet) {
352 tty->ctrl_status |= TIOCPKT_FLUSHREAD;
Peter Hurley6c677162013-12-02 14:24:46 -0500353 if (waitqueue_active(&tty->link->read_wait))
354 wake_up_interruptible(&tty->link->read_wait);
Peter Hurleya30737a2013-03-11 16:44:22 -0400355 }
356 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
357}
358
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359/**
360 * n_tty_flush_buffer - clean input queue
361 * @tty: terminal device
362 *
Peter Hurley25518c62013-03-11 16:44:31 -0400363 * Flush the input buffer. Called when the tty layer wants the
364 * buffer flushed (eg at hangup) or when the N_TTY line discipline
365 * internally has to clean the pending queue (for example some signals).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400367 * Holds termios_rwsem to exclude producer/consumer while
368 * buffer indices are reset.
369 *
370 * Locking: ctrl_lock, exclusive termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 */
Alan Cox4edf1822008-02-08 04:18:44 -0800372
373static void n_tty_flush_buffer(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374{
Peter Hurley6d76bd22013-06-15 09:14:26 -0400375 down_write(&tty->termios_rwsem);
Peter Hurleyb66f4fa2013-03-11 16:44:32 -0400376 reset_buffer_flags(tty->disc_data);
377 n_tty_set_room(tty);
Alan Cox4edf1822008-02-08 04:18:44 -0800378
Peter Hurleya30737a2013-03-11 16:44:22 -0400379 if (tty->link)
380 n_tty_packet_mode_flush(tty);
Peter Hurley6d76bd22013-06-15 09:14:26 -0400381 up_write(&tty->termios_rwsem);
382}
383
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384/**
385 * n_tty_chars_in_buffer - report available bytes
386 * @tty: tty device
387 *
388 * Report the number of characters buffered to be delivered to user
Alan Cox4edf1822008-02-08 04:18:44 -0800389 * at this instant in time.
Alan Cox17b82062008-10-13 10:45:06 +0100390 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400391 * Locking: exclusive termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 */
Alan Cox4edf1822008-02-08 04:18:44 -0800393
Peter Hurleya19d0c62013-06-15 09:14:18 -0400394static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
395{
Peter Hurley6d76bd22013-06-15 09:14:26 -0400396 ssize_t n;
397
Peter Hurley47534082013-06-15 09:14:19 -0400398 WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__);
Peter Hurley6d76bd22013-06-15 09:14:26 -0400399
400 down_write(&tty->termios_rwsem);
401 n = chars_in_buffer(tty);
402 up_write(&tty->termios_rwsem);
403 return n;
Peter Hurleya19d0c62013-06-15 09:14:18 -0400404}
405
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406/**
407 * is_utf8_continuation - utf8 multibyte check
408 * @c: byte to check
409 *
410 * Returns true if the utf8 character 'c' is a multibyte continuation
411 * character. We use this to correctly compute the on screen size
412 * of the character when printing
413 */
Alan Cox4edf1822008-02-08 04:18:44 -0800414
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415static inline int is_utf8_continuation(unsigned char c)
416{
417 return (c & 0xc0) == 0x80;
418}
419
420/**
421 * is_continuation - multibyte check
422 * @c: byte to check
423 *
424 * Returns true if the utf8 character 'c' is a multibyte continuation
425 * character and the terminal is in unicode mode.
426 */
Alan Cox4edf1822008-02-08 04:18:44 -0800427
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428static inline int is_continuation(unsigned char c, struct tty_struct *tty)
429{
430 return I_IUTF8(tty) && is_utf8_continuation(c);
431}
432
433/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000434 * do_output_char - output one character
435 * @c: character (or partial unicode symbol)
436 * @tty: terminal device
437 * @space: space available in tty driver write buffer
438 *
439 * This is a helper function that handles one output character
440 * (including special characters like TAB, CR, LF, etc.),
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600441 * doing OPOST processing and putting the results in the
442 * tty driver's write buffer.
Joe Petersona88a69c2009-01-02 13:40:53 +0000443 *
444 * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY
445 * and NLDLY. They simply aren't relevant in the world today.
446 * If you ever need them, add them here.
447 *
448 * Returns the number of bytes of buffer space used or -1 if
449 * no space left.
450 *
451 * Locking: should be called under the output_lock to protect
452 * the column state and space left in the buffer
453 */
454
455static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
456{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200457 struct n_tty_data *ldata = tty->disc_data;
Joe Petersona88a69c2009-01-02 13:40:53 +0000458 int spaces;
459
460 if (!space)
461 return -1;
Alan Cox300a6202009-01-02 13:41:04 +0000462
Joe Petersona88a69c2009-01-02 13:40:53 +0000463 switch (c) {
464 case '\n':
465 if (O_ONLRET(tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200466 ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000467 if (O_ONLCR(tty)) {
468 if (space < 2)
469 return -1;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200470 ldata->canon_column = ldata->column = 0;
Linus Torvalds37f81fa2009-09-05 12:46:07 -0700471 tty->ops->write(tty, "\r\n", 2);
Joe Petersona88a69c2009-01-02 13:40:53 +0000472 return 2;
473 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200474 ldata->canon_column = ldata->column;
Joe Petersona88a69c2009-01-02 13:40:53 +0000475 break;
476 case '\r':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200477 if (O_ONOCR(tty) && ldata->column == 0)
Joe Petersona88a69c2009-01-02 13:40:53 +0000478 return 0;
479 if (O_OCRNL(tty)) {
480 c = '\n';
481 if (O_ONLRET(tty))
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200482 ldata->canon_column = ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000483 break;
484 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200485 ldata->canon_column = ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000486 break;
487 case '\t':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200488 spaces = 8 - (ldata->column & 7);
Joe Petersona88a69c2009-01-02 13:40:53 +0000489 if (O_TABDLY(tty) == XTABS) {
490 if (space < spaces)
491 return -1;
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200492 ldata->column += spaces;
Joe Petersona88a69c2009-01-02 13:40:53 +0000493 tty->ops->write(tty, " ", spaces);
494 return spaces;
495 }
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200496 ldata->column += spaces;
Joe Petersona88a69c2009-01-02 13:40:53 +0000497 break;
498 case '\b':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200499 if (ldata->column > 0)
500 ldata->column--;
Joe Petersona88a69c2009-01-02 13:40:53 +0000501 break;
502 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000503 if (!iscntrl(c)) {
504 if (O_OLCUC(tty))
505 c = toupper(c);
506 if (!is_continuation(c, tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200507 ldata->column++;
Joe Petersona59c0d62009-01-02 13:43:25 +0000508 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000509 break;
510 }
511
512 tty_put_char(tty, c);
513 return 1;
514}
515
516/**
517 * process_output - output post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 * @c: character (or partial unicode symbol)
519 * @tty: terminal device
520 *
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600521 * Output one character with OPOST processing.
522 * Returns -1 when the output device is full and the character
523 * must be retried.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000525 * Locking: output_lock to protect column state and space left
526 * (also, this is called from n_tty_write under the
527 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 */
Alan Cox4edf1822008-02-08 04:18:44 -0800529
Joe Petersona88a69c2009-01-02 13:40:53 +0000530static int process_output(unsigned char c, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531{
Jiri Slabybddc7152012-10-18 22:26:42 +0200532 struct n_tty_data *ldata = tty->disc_data;
Joe Petersona88a69c2009-01-02 13:40:53 +0000533 int space, retval;
534
Jiri Slabybddc7152012-10-18 22:26:42 +0200535 mutex_lock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536
Alan Coxf34d7a52008-04-30 00:54:13 -0700537 space = tty_write_room(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +0000538 retval = do_output_char(c, tty, space);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539
Jiri Slabybddc7152012-10-18 22:26:42 +0200540 mutex_unlock(&ldata->output_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000541 if (retval < 0)
542 return -1;
543 else
544 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545}
546
547/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000548 * process_output_block - block post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 * @tty: terminal device
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600550 * @buf: character buffer
551 * @nr: number of bytes to output
552 *
553 * Output a block of characters with OPOST processing.
554 * Returns the number of characters output.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 *
556 * This path is used to speed up block console writes, among other
557 * things when processing blocks of output data. It handles only
558 * the simple cases normally found and helps to generate blocks of
559 * symbols for the console driver and thus improve performance.
560 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000561 * Locking: output_lock to protect column state and space left
562 * (also, this is called from n_tty_write under the
563 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 */
Alan Cox4edf1822008-02-08 04:18:44 -0800565
Joe Petersona88a69c2009-01-02 13:40:53 +0000566static ssize_t process_output_block(struct tty_struct *tty,
567 const unsigned char *buf, unsigned int nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200569 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 int space;
Thorsten Wißmannbbd20752011-12-08 17:47:33 +0100571 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 const unsigned char *cp;
573
Jiri Slabybddc7152012-10-18 22:26:42 +0200574 mutex_lock(&ldata->output_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000575
Alan Coxf34d7a52008-04-30 00:54:13 -0700576 space = tty_write_room(tty);
Alan Cox300a6202009-01-02 13:41:04 +0000577 if (!space) {
Jiri Slabybddc7152012-10-18 22:26:42 +0200578 mutex_unlock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 return 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000580 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 if (nr > space)
582 nr = space;
583
584 for (i = 0, cp = buf; i < nr; i++, cp++) {
Joe Petersona59c0d62009-01-02 13:43:25 +0000585 unsigned char c = *cp;
586
587 switch (c) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 case '\n':
589 if (O_ONLRET(tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200590 ldata->column = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 if (O_ONLCR(tty))
592 goto break_out;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200593 ldata->canon_column = ldata->column;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 break;
595 case '\r':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200596 if (O_ONOCR(tty) && ldata->column == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 goto break_out;
598 if (O_OCRNL(tty))
599 goto break_out;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200600 ldata->canon_column = ldata->column = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 break;
602 case '\t':
603 goto break_out;
604 case '\b':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200605 if (ldata->column > 0)
606 ldata->column--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 break;
608 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000609 if (!iscntrl(c)) {
610 if (O_OLCUC(tty))
611 goto break_out;
612 if (!is_continuation(c, tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200613 ldata->column++;
Joe Petersona59c0d62009-01-02 13:43:25 +0000614 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 break;
616 }
617 }
618break_out:
Alan Coxf34d7a52008-04-30 00:54:13 -0700619 i = tty->ops->write(tty, buf, i);
Joe Petersona88a69c2009-01-02 13:40:53 +0000620
Jiri Slabybddc7152012-10-18 22:26:42 +0200621 mutex_unlock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 return i;
623}
624
Joe Petersona88a69c2009-01-02 13:40:53 +0000625/**
626 * process_echoes - write pending echo characters
627 * @tty: terminal device
628 *
629 * Write previously buffered echo (and other ldisc-generated)
630 * characters to the tty.
631 *
632 * Characters generated by the ldisc (including echoes) need to
633 * be buffered because the driver's write buffer can fill during
634 * heavy program output. Echoing straight to the driver will
635 * often fail under these conditions, causing lost characters and
636 * resulting mismatches of ldisc state information.
637 *
638 * Since the ldisc state must represent the characters actually sent
639 * to the driver at the time of the write, operations like certain
640 * changes in column state are also saved in the buffer and executed
641 * here.
642 *
643 * A circular fifo buffer is used so that the most recent characters
644 * are prioritized. Also, when control characters are echoed with a
645 * prefixed "^", the pair is treated atomically and thus not separated.
646 *
Peter Hurley019ebdf2013-06-15 10:04:25 -0400647 * Locking: callers must hold output_lock
Joe Petersona88a69c2009-01-02 13:40:53 +0000648 */
649
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400650static size_t __process_echoes(struct tty_struct *tty)
Joe Petersona88a69c2009-01-02 13:40:53 +0000651{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200652 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400653 int space, old_space;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400654 size_t tail;
Joe Petersona88a69c2009-01-02 13:40:53 +0000655 unsigned char c;
Joe Petersona88a69c2009-01-02 13:40:53 +0000656
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400657 old_space = space = tty_write_room(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +0000658
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400659 tail = ldata->echo_tail;
Peter Hurley29c7c5c2013-06-15 10:04:28 -0400660 while (ldata->echo_commit != tail) {
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400661 c = echo_buf(ldata, tail);
Joe Petersona88a69c2009-01-02 13:40:53 +0000662 if (c == ECHO_OP_START) {
663 unsigned char op;
Joe Petersona88a69c2009-01-02 13:40:53 +0000664 int no_space_left = 0;
665
666 /*
667 * If the buffer byte is the start of a multi-byte
668 * operation, get the next byte, which is either the
669 * op code or a control character value.
670 */
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400671 op = echo_buf(ldata, tail + 1);
Alan Cox300a6202009-01-02 13:41:04 +0000672
Joe Petersona88a69c2009-01-02 13:40:53 +0000673 switch (op) {
674 unsigned int num_chars, num_bs;
675
676 case ECHO_OP_ERASE_TAB:
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400677 num_chars = echo_buf(ldata, tail + 2);
Joe Petersona88a69c2009-01-02 13:40:53 +0000678
679 /*
680 * Determine how many columns to go back
681 * in order to erase the tab.
682 * This depends on the number of columns
683 * used by other characters within the tab
684 * area. If this (modulo 8) count is from
685 * the start of input rather than from a
686 * previous tab, we offset by canon column.
687 * Otherwise, tab spacing is normal.
688 */
689 if (!(num_chars & 0x80))
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200690 num_chars += ldata->canon_column;
Joe Petersona88a69c2009-01-02 13:40:53 +0000691 num_bs = 8 - (num_chars & 7);
692
693 if (num_bs > space) {
694 no_space_left = 1;
695 break;
696 }
697 space -= num_bs;
698 while (num_bs--) {
699 tty_put_char(tty, '\b');
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200700 if (ldata->column > 0)
701 ldata->column--;
Joe Petersona88a69c2009-01-02 13:40:53 +0000702 }
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400703 tail += 3;
Joe Petersona88a69c2009-01-02 13:40:53 +0000704 break;
705
706 case ECHO_OP_SET_CANON_COL:
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200707 ldata->canon_column = ldata->column;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400708 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000709 break;
710
711 case ECHO_OP_MOVE_BACK_COL:
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200712 if (ldata->column > 0)
713 ldata->column--;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400714 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000715 break;
716
717 case ECHO_OP_START:
718 /* This is an escaped echo op start code */
719 if (!space) {
720 no_space_left = 1;
721 break;
722 }
723 tty_put_char(tty, ECHO_OP_START);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200724 ldata->column++;
Joe Petersona88a69c2009-01-02 13:40:53 +0000725 space--;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400726 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000727 break;
728
729 default:
Joe Petersona88a69c2009-01-02 13:40:53 +0000730 /*
Joe Peterson62b26352009-09-09 15:03:47 -0600731 * If the op is not a special byte code,
732 * it is a ctrl char tagged to be echoed
733 * as "^X" (where X is the letter
734 * representing the control char).
735 * Note that we must ensure there is
736 * enough space for the whole ctrl pair.
737 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000738 */
Joe Peterson62b26352009-09-09 15:03:47 -0600739 if (space < 2) {
740 no_space_left = 1;
741 break;
742 }
743 tty_put_char(tty, '^');
744 tty_put_char(tty, op ^ 0100);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200745 ldata->column += 2;
Joe Peterson62b26352009-09-09 15:03:47 -0600746 space -= 2;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400747 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000748 }
749
750 if (no_space_left)
751 break;
752 } else {
Peter Hurley582f5592013-05-17 12:49:48 -0400753 if (O_OPOST(tty)) {
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600754 int retval = do_output_char(c, tty, space);
755 if (retval < 0)
756 break;
757 space -= retval;
758 } else {
759 if (!space)
760 break;
761 tty_put_char(tty, c);
762 space -= 1;
763 }
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400764 tail += 1;
Joe Petersona88a69c2009-01-02 13:40:53 +0000765 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000766 }
767
Peter Hurleycbfd0342013-06-15 10:04:26 -0400768 /* If the echo buffer is nearly full (so that the possibility exists
769 * of echo overrun before the next commit), then discard enough
770 * data at the tail to prevent a subsequent overrun */
771 while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) {
Roel Kluinc476f652013-10-11 22:08:49 +0200772 if (echo_buf(ldata, tail) == ECHO_OP_START) {
Peter Hurley6f222532013-11-08 09:42:18 -0500773 if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB)
Peter Hurleycbfd0342013-06-15 10:04:26 -0400774 tail += 3;
775 else
776 tail += 2;
777 } else
778 tail++;
779 }
780
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400781 ldata->echo_tail = tail;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400782 return old_space - space;
Joe Petersona88a69c2009-01-02 13:40:53 +0000783}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784
Peter Hurley17bd7902013-06-15 10:04:24 -0400785static void commit_echoes(struct tty_struct *tty)
786{
787 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400788 size_t nr, old, echoed;
Peter Hurleycbfd0342013-06-15 10:04:26 -0400789 size_t head;
790
791 head = ldata->echo_head;
792 old = ldata->echo_commit - ldata->echo_tail;
793
794 /* Process committed echoes if the accumulated # of bytes
795 * is over the threshold (and try again each time another
796 * block is accumulated) */
797 nr = head - ldata->echo_tail;
798 if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK))
799 return;
Peter Hurley17bd7902013-06-15 10:04:24 -0400800
Peter Hurley019ebdf2013-06-15 10:04:25 -0400801 mutex_lock(&ldata->output_lock);
Peter Hurleycbfd0342013-06-15 10:04:26 -0400802 ldata->echo_commit = head;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400803 echoed = __process_echoes(tty);
Peter Hurley019ebdf2013-06-15 10:04:25 -0400804 mutex_unlock(&ldata->output_lock);
805
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400806 if (echoed && tty->ops->flush_chars)
Peter Hurley019ebdf2013-06-15 10:04:25 -0400807 tty->ops->flush_chars(tty);
808}
809
810static void process_echoes(struct tty_struct *tty)
811{
812 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400813 size_t echoed;
Peter Hurley019ebdf2013-06-15 10:04:25 -0400814
815 if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_tail)
816 return;
817
818 mutex_lock(&ldata->output_lock);
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400819 echoed = __process_echoes(tty);
Peter Hurley019ebdf2013-06-15 10:04:25 -0400820 mutex_unlock(&ldata->output_lock);
821
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400822 if (echoed && tty->ops->flush_chars)
Peter Hurley019ebdf2013-06-15 10:04:25 -0400823 tty->ops->flush_chars(tty);
Peter Hurley17bd7902013-06-15 10:04:24 -0400824}
825
Peter Hurleycbfd0342013-06-15 10:04:26 -0400826static void flush_echoes(struct tty_struct *tty)
827{
828 struct n_tty_data *ldata = tty->disc_data;
829
830 if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_head)
831 return;
832
833 mutex_lock(&ldata->output_lock);
834 ldata->echo_commit = ldata->echo_head;
835 __process_echoes(tty);
836 mutex_unlock(&ldata->output_lock);
837}
838
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000840 * add_echo_byte - add a byte to the echo buffer
841 * @c: unicode byte to echo
Jiri Slaby57c94122012-10-18 22:26:43 +0200842 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000843 *
844 * Add a character or operation byte to the echo buffer.
Joe Petersona88a69c2009-01-02 13:40:53 +0000845 */
846
Peter Hurleycbfd0342013-06-15 10:04:26 -0400847static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000848{
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400849 *echo_buf_addr(ldata, ldata->echo_head++) = c;
Joe Petersona88a69c2009-01-02 13:40:53 +0000850}
851
852/**
853 * echo_move_back_col - add operation to move back a column
Jiri Slaby57c94122012-10-18 22:26:43 +0200854 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000855 *
856 * Add an operation to the echo buffer to move back one column.
Joe Petersona88a69c2009-01-02 13:40:53 +0000857 */
858
Jiri Slaby57c94122012-10-18 22:26:43 +0200859static void echo_move_back_col(struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000860{
Jiri Slaby57c94122012-10-18 22:26:43 +0200861 add_echo_byte(ECHO_OP_START, ldata);
862 add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000863}
864
865/**
866 * echo_set_canon_col - add operation to set the canon column
Jiri Slaby57c94122012-10-18 22:26:43 +0200867 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000868 *
869 * Add an operation to the echo buffer to set the canon column
870 * to the current column.
Joe Petersona88a69c2009-01-02 13:40:53 +0000871 */
872
Jiri Slaby57c94122012-10-18 22:26:43 +0200873static void echo_set_canon_col(struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000874{
Jiri Slaby57c94122012-10-18 22:26:43 +0200875 add_echo_byte(ECHO_OP_START, ldata);
876 add_echo_byte(ECHO_OP_SET_CANON_COL, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000877}
878
879/**
880 * echo_erase_tab - add operation to erase a tab
881 * @num_chars: number of character columns already used
882 * @after_tab: true if num_chars starts after a previous tab
Jiri Slaby57c94122012-10-18 22:26:43 +0200883 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000884 *
885 * Add an operation to the echo buffer to erase a tab.
886 *
887 * Called by the eraser function, which knows how many character
888 * columns have been used since either a previous tab or the start
889 * of input. This information will be used later, along with
890 * canon column (if applicable), to go back the correct number
891 * of columns.
Joe Petersona88a69c2009-01-02 13:40:53 +0000892 */
893
894static void echo_erase_tab(unsigned int num_chars, int after_tab,
Jiri Slaby57c94122012-10-18 22:26:43 +0200895 struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000896{
Jiri Slaby57c94122012-10-18 22:26:43 +0200897 add_echo_byte(ECHO_OP_START, ldata);
898 add_echo_byte(ECHO_OP_ERASE_TAB, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000899
900 /* We only need to know this modulo 8 (tab spacing) */
901 num_chars &= 7;
902
903 /* Set the high bit as a flag if num_chars is after a previous tab */
904 if (after_tab)
905 num_chars |= 0x80;
Alan Cox300a6202009-01-02 13:41:04 +0000906
Jiri Slaby57c94122012-10-18 22:26:43 +0200907 add_echo_byte(num_chars, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000908}
909
910/**
911 * echo_char_raw - echo a character raw
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912 * @c: unicode byte to echo
913 * @tty: terminal device
914 *
Alan Cox4edf1822008-02-08 04:18:44 -0800915 * Echo user input back onto the screen. This must be called only when
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 * L_ECHO(tty) is true. Called from the driver receive_buf path.
Alan Cox17b82062008-10-13 10:45:06 +0100917 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000918 * This variant does not treat control characters specially.
Joe Petersona88a69c2009-01-02 13:40:53 +0000919 */
920
Jiri Slaby57c94122012-10-18 22:26:43 +0200921static void echo_char_raw(unsigned char c, struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000922{
Joe Petersona88a69c2009-01-02 13:40:53 +0000923 if (c == ECHO_OP_START) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200924 add_echo_byte(ECHO_OP_START, ldata);
925 add_echo_byte(ECHO_OP_START, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000926 } else {
Jiri Slaby57c94122012-10-18 22:26:43 +0200927 add_echo_byte(c, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000928 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000929}
930
931/**
932 * echo_char - echo a character
933 * @c: unicode byte to echo
934 * @tty: terminal device
935 *
936 * Echo user input back onto the screen. This must be called only when
937 * L_ECHO(tty) is true. Called from the driver receive_buf path.
938 *
Joe Peterson62b26352009-09-09 15:03:47 -0600939 * This variant tags control characters to be echoed as "^X"
940 * (where X is the letter representing the control char).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941 */
942
943static void echo_char(unsigned char c, struct tty_struct *tty)
944{
Jiri Slabybddc7152012-10-18 22:26:42 +0200945 struct n_tty_data *ldata = tty->disc_data;
946
Joe Petersona88a69c2009-01-02 13:40:53 +0000947 if (c == ECHO_OP_START) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200948 add_echo_byte(ECHO_OP_START, ldata);
949 add_echo_byte(ECHO_OP_START, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000950 } else {
Joe Peterson62b26352009-09-09 15:03:47 -0600951 if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t')
Jiri Slaby57c94122012-10-18 22:26:43 +0200952 add_echo_byte(ECHO_OP_START, ldata);
953 add_echo_byte(c, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000954 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955}
956
Alan Cox17b82062008-10-13 10:45:06 +0100957/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000958 * finish_erasing - complete erase
Jiri Slaby57c94122012-10-18 22:26:43 +0200959 * @ldata: n_tty data
Alan Cox17b82062008-10-13 10:45:06 +0100960 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000961
Jiri Slaby57c94122012-10-18 22:26:43 +0200962static inline void finish_erasing(struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200964 if (ldata->erasing) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200965 echo_char_raw('/', ldata);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200966 ldata->erasing = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967 }
968}
969
970/**
971 * eraser - handle erase function
972 * @c: character input
973 * @tty: terminal device
974 *
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200975 * Perform erase and necessary output when an erase character is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 * present in the stream from the driver layer. Handles the complexities
977 * of UTF-8 multibyte symbols.
Alan Cox17b82062008-10-13 10:45:06 +0100978 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400979 * n_tty_receive_buf()/producer path:
980 * caller holds non-exclusive termios_rwsem
981 * modifies read_head
982 *
983 * Modifying the read_head is not considered a publish in this context
984 * because canonical mode is active -- only canon_head publishes
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985 */
Alan Cox4edf1822008-02-08 04:18:44 -0800986
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987static void eraser(unsigned char c, struct tty_struct *tty)
988{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200989 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700990 enum { ERASE, WERASE, KILL } kill_type;
Peter Hurleybc5a5e32013-06-15 09:14:21 -0400991 size_t head;
992 size_t cnt;
993 int seen_alnums;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200995 if (ldata->read_head == ldata->canon_head) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +0000996 /* process_output('\a', tty); */ /* what do you think? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 return;
998 }
999 if (c == ERASE_CHAR(tty))
1000 kill_type = ERASE;
1001 else if (c == WERASE_CHAR(tty))
1002 kill_type = WERASE;
1003 else {
1004 if (!L_ECHO(tty)) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001005 ldata->read_head = ldata->canon_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006 return;
1007 }
1008 if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001009 ldata->read_head = ldata->canon_head;
Jiri Slaby57c94122012-10-18 22:26:43 +02001010 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 echo_char(KILL_CHAR(tty), tty);
1012 /* Add a newline if ECHOK is on and ECHOKE is off. */
1013 if (L_ECHOK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001014 echo_char_raw('\n', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015 return;
1016 }
1017 kill_type = KILL;
1018 }
1019
1020 seen_alnums = 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001021 while (ldata->read_head != ldata->canon_head) {
1022 head = ldata->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023
1024 /* erase a single possibly multibyte character */
1025 do {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001026 head--;
1027 c = read_buf(ldata, head);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001028 } while (is_continuation(c, tty) && head != ldata->canon_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001029
1030 /* do not partially erase */
1031 if (is_continuation(c, tty))
1032 break;
1033
1034 if (kill_type == WERASE) {
1035 /* Equivalent to BSD's ALTWERASE. */
1036 if (isalnum(c) || c == '_')
1037 seen_alnums++;
1038 else if (seen_alnums)
1039 break;
1040 }
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001041 cnt = ldata->read_head - head;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001042 ldata->read_head = head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043 if (L_ECHO(tty)) {
1044 if (L_ECHOPRT(tty)) {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001045 if (!ldata->erasing) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001046 echo_char_raw('\\', ldata);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001047 ldata->erasing = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048 }
1049 /* if cnt > 1, output a multi-byte character */
1050 echo_char(c, tty);
1051 while (--cnt > 0) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001052 head++;
1053 echo_char_raw(read_buf(ldata, head), ldata);
Jiri Slaby57c94122012-10-18 22:26:43 +02001054 echo_move_back_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055 }
1056 } else if (kill_type == ERASE && !L_ECHOE(tty)) {
1057 echo_char(ERASE_CHAR(tty), tty);
1058 } else if (c == '\t') {
Joe Petersona88a69c2009-01-02 13:40:53 +00001059 unsigned int num_chars = 0;
1060 int after_tab = 0;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001061 size_t tail = ldata->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001062
Joe Petersona88a69c2009-01-02 13:40:53 +00001063 /*
1064 * Count the columns used for characters
1065 * since the start of input or after a
1066 * previous tab.
1067 * This info is used to go back the correct
1068 * number of columns.
1069 */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001070 while (tail != ldata->canon_head) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001071 tail--;
1072 c = read_buf(ldata, tail);
Joe Petersona88a69c2009-01-02 13:40:53 +00001073 if (c == '\t') {
1074 after_tab = 1;
1075 break;
Alan Cox300a6202009-01-02 13:41:04 +00001076 } else if (iscntrl(c)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077 if (L_ECHOCTL(tty))
Joe Petersona88a69c2009-01-02 13:40:53 +00001078 num_chars += 2;
1079 } else if (!is_continuation(c, tty)) {
1080 num_chars++;
1081 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082 }
Jiri Slaby57c94122012-10-18 22:26:43 +02001083 echo_erase_tab(num_chars, after_tab, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084 } else {
1085 if (iscntrl(c) && L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001086 echo_char_raw('\b', ldata);
1087 echo_char_raw(' ', ldata);
1088 echo_char_raw('\b', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 }
1090 if (!iscntrl(c) || L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001091 echo_char_raw('\b', ldata);
1092 echo_char_raw(' ', ldata);
1093 echo_char_raw('\b', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 }
1095 }
1096 }
1097 if (kill_type == ERASE)
1098 break;
1099 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001100 if (ldata->read_head == ldata->canon_head && L_ECHO(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001101 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102}
1103
1104/**
1105 * isig - handle the ISIG optio
1106 * @sig: signal
1107 * @tty: terminal
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 *
Peter Hurley8c985d12013-03-06 08:38:19 -05001109 * Called when a signal is being sent due to terminal input.
1110 * Called from the driver receive_buf path so serialized.
Alan Cox17b82062008-10-13 10:45:06 +01001111 *
Peter Hurley8c985d12013-03-06 08:38:19 -05001112 * Locking: ctrl_lock
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113 */
Alan Cox4edf1822008-02-08 04:18:44 -08001114
Peter Hurley4b293492013-07-24 08:29:55 -04001115static void isig(int sig, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116{
Peter Hurley8c985d12013-03-06 08:38:19 -05001117 struct pid *tty_pgrp = tty_get_pgrp(tty);
1118 if (tty_pgrp) {
1119 kill_pgrp(tty_pgrp, sig, 1);
1120 put_pid(tty_pgrp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121 }
1122}
1123
1124/**
1125 * n_tty_receive_break - handle break
1126 * @tty: terminal
1127 *
1128 * An RS232 break event has been hit in the incoming bitstream. This
1129 * can cause a variety of events depending upon the termios settings.
1130 *
Peter Hurley6d76bd22013-06-15 09:14:26 -04001131 * n_tty_receive_buf()/producer path:
1132 * caller holds non-exclusive termios_rwsem
1133 * publishes read_head via put_tty_queue()
1134 *
1135 * Note: may get exclusive termios_rwsem if flushing input buffer
Linus Torvalds1da177e2005-04-16 15:20:36 -07001136 */
Alan Cox4edf1822008-02-08 04:18:44 -08001137
Peter Hurley4b293492013-07-24 08:29:55 -04001138static void n_tty_receive_break(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139{
Jiri Slaby57c94122012-10-18 22:26:43 +02001140 struct n_tty_data *ldata = tty->disc_data;
1141
Linus Torvalds1da177e2005-04-16 15:20:36 -07001142 if (I_IGNBRK(tty))
1143 return;
1144 if (I_BRKINT(tty)) {
Peter Hurley8c985d12013-03-06 08:38:19 -05001145 isig(SIGINT, tty);
1146 if (!L_NOFLSH(tty)) {
Peter Hurley6d76bd22013-06-15 09:14:26 -04001147 /* flushing needs exclusive termios_rwsem */
1148 up_read(&tty->termios_rwsem);
Peter Hurley8c985d12013-03-06 08:38:19 -05001149 n_tty_flush_buffer(tty);
1150 tty_driver_flush_buffer(tty);
Peter Hurley6d76bd22013-06-15 09:14:26 -04001151 down_read(&tty->termios_rwsem);
Peter Hurley8c985d12013-03-06 08:38:19 -05001152 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153 return;
1154 }
1155 if (I_PARMRK(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001156 put_tty_queue('\377', ldata);
1157 put_tty_queue('\0', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001158 }
Jiri Slaby57c94122012-10-18 22:26:43 +02001159 put_tty_queue('\0', ldata);
Peter Hurley6c677162013-12-02 14:24:46 -05001160 if (waitqueue_active(&tty->read_wait))
1161 wake_up_interruptible(&tty->read_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162}
1163
1164/**
1165 * n_tty_receive_overrun - handle overrun reporting
1166 * @tty: terminal
1167 *
1168 * Data arrived faster than we could process it. While the tty
1169 * driver has flagged this the bits that were missed are gone
1170 * forever.
1171 *
1172 * Called from the receive_buf path so single threaded. Does not
1173 * need locking as num_overrun and overrun_time are function
1174 * private.
1175 */
Alan Cox4edf1822008-02-08 04:18:44 -08001176
Peter Hurley4b293492013-07-24 08:29:55 -04001177static void n_tty_receive_overrun(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001179 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180 char buf[64];
1181
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001182 ldata->num_overrun++;
1183 if (time_after(jiffies, ldata->overrun_time + HZ) ||
1184 time_after(ldata->overrun_time, jiffies)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185 printk(KERN_WARNING "%s: %d input overrun(s)\n",
1186 tty_name(tty, buf),
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001187 ldata->num_overrun);
1188 ldata->overrun_time = jiffies;
1189 ldata->num_overrun = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190 }
1191}
1192
1193/**
1194 * n_tty_receive_parity_error - error notifier
1195 * @tty: terminal device
1196 * @c: character
1197 *
1198 * Process a parity error and queue the right data to indicate
Peter Hurley6d76bd22013-06-15 09:14:26 -04001199 * the error case if necessary.
1200 *
1201 * n_tty_receive_buf()/producer path:
1202 * caller holds non-exclusive termios_rwsem
1203 * publishes read_head via put_tty_queue()
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 */
Peter Hurley4b293492013-07-24 08:29:55 -04001205static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206{
Jiri Slaby57c94122012-10-18 22:26:43 +02001207 struct n_tty_data *ldata = tty->disc_data;
1208
Alan Cox4edf1822008-02-08 04:18:44 -08001209 if (I_IGNPAR(tty))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211 if (I_PARMRK(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001212 put_tty_queue('\377', ldata);
1213 put_tty_queue('\0', ldata);
1214 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 } else if (I_INPCK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001216 put_tty_queue('\0', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217 else
Jiri Slaby57c94122012-10-18 22:26:43 +02001218 put_tty_queue(c, ldata);
Peter Hurley6c677162013-12-02 14:24:46 -05001219 if (waitqueue_active(&tty->read_wait))
1220 wake_up_interruptible(&tty->read_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221}
1222
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001223static void
1224n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c)
1225{
1226 if (!L_NOFLSH(tty)) {
1227 /* flushing needs exclusive termios_rwsem */
1228 up_read(&tty->termios_rwsem);
1229 n_tty_flush_buffer(tty);
1230 tty_driver_flush_buffer(tty);
1231 down_read(&tty->termios_rwsem);
1232 }
1233 if (I_IXON(tty))
1234 start_tty(tty);
1235 if (L_ECHO(tty)) {
1236 echo_char(c, tty);
1237 commit_echoes(tty);
1238 }
1239 isig(signal, tty);
1240 return;
1241}
1242
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243/**
1244 * n_tty_receive_char - perform processing
1245 * @tty: terminal device
1246 * @c: character
1247 *
1248 * Process an individual character of input received from the driver.
Alan Cox4edf1822008-02-08 04:18:44 -08001249 * This is serialized with respect to itself by the rules for the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250 * driver above.
Peter Hurley6d76bd22013-06-15 09:14:26 -04001251 *
1252 * n_tty_receive_buf()/producer path:
1253 * caller holds non-exclusive termios_rwsem
1254 * publishes canon_head if canonical mode is active
1255 * otherwise, publishes read_head via put_tty_queue()
Peter Hurleye60d27c2013-07-24 08:29:56 -04001256 *
1257 * Returns 1 if LNEXT was received, else returns 0
Linus Torvalds1da177e2005-04-16 15:20:36 -07001258 */
1259
Peter Hurleye60d27c2013-07-24 08:29:56 -04001260static int
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001261n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001263 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265 if (I_IXON(tty)) {
1266 if (c == START_CHAR(tty)) {
1267 start_tty(tty);
Peter Hurley17bd7902013-06-15 10:04:24 -04001268 commit_echoes(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001269 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270 }
1271 if (c == STOP_CHAR(tty)) {
1272 stop_tty(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001273 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274 }
1275 }
Joe Peterson575537b32008-04-30 00:53:30 -07001276
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277 if (L_ISIG(tty)) {
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001278 if (c == INTR_CHAR(tty)) {
1279 n_tty_receive_signal_char(tty, SIGINT, c);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001280 return 0;
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001281 } else if (c == QUIT_CHAR(tty)) {
1282 n_tty_receive_signal_char(tty, SIGQUIT, c);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001283 return 0;
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001284 } else if (c == SUSP_CHAR(tty)) {
1285 n_tty_receive_signal_char(tty, SIGTSTP, c);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001286 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287 }
1288 }
Joe Peterson575537b32008-04-30 00:53:30 -07001289
Peter Hurley855df3c2013-07-24 08:29:50 -04001290 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
1291 start_tty(tty);
1292 process_echoes(tty);
1293 }
1294
Joe Peterson575537b32008-04-30 00:53:30 -07001295 if (c == '\r') {
1296 if (I_IGNCR(tty))
Peter Hurleye60d27c2013-07-24 08:29:56 -04001297 return 0;
Joe Peterson575537b32008-04-30 00:53:30 -07001298 if (I_ICRNL(tty))
1299 c = '\n';
1300 } else if (c == '\n' && I_INLCR(tty))
1301 c = '\r';
1302
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001303 if (ldata->icanon) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304 if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
1305 (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
1306 eraser(c, tty);
Peter Hurley17bd7902013-06-15 10:04:24 -04001307 commit_echoes(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001308 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309 }
1310 if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001311 ldata->lnext = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312 if (L_ECHO(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001313 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314 if (L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001315 echo_char_raw('^', ldata);
1316 echo_char_raw('\b', ldata);
Peter Hurley17bd7902013-06-15 10:04:24 -04001317 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 }
1319 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001320 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001322 if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001323 size_t tail = ldata->canon_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001324
Jiri Slaby57c94122012-10-18 22:26:43 +02001325 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001326 echo_char(c, tty);
Jiri Slaby57c94122012-10-18 22:26:43 +02001327 echo_char_raw('\n', ldata);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001328 while (tail != ldata->read_head) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001329 echo_char(read_buf(ldata, tail), tty);
1330 tail++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331 }
Peter Hurley17bd7902013-06-15 10:04:24 -04001332 commit_echoes(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001333 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334 }
1335 if (c == '\n') {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001336 if (L_ECHO(tty) || L_ECHONL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001337 echo_char_raw('\n', ldata);
Peter Hurley17bd7902013-06-15 10:04:24 -04001338 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339 }
1340 goto handle_newline;
1341 }
1342 if (c == EOF_CHAR(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343 c = __DISABLED_CHAR;
1344 goto handle_newline;
1345 }
1346 if ((c == EOL_CHAR(tty)) ||
1347 (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
1348 /*
1349 * XXX are EOL_CHAR and EOL2_CHAR echoed?!?
1350 */
1351 if (L_ECHO(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001352 /* Record the column of first canon char. */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001353 if (ldata->canon_head == ldata->read_head)
Jiri Slaby57c94122012-10-18 22:26:43 +02001354 echo_set_canon_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001355 echo_char(c, tty);
Peter Hurley17bd7902013-06-15 10:04:24 -04001356 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001357 }
1358 /*
1359 * XXX does PARMRK doubling happen for
1360 * EOL_CHAR and EOL2_CHAR?
1361 */
Peter Hurley001ba922013-12-02 14:24:44 -05001362 if (c == (unsigned char) '\377' && I_PARMRK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001363 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364
Alan Cox4edf1822008-02-08 04:18:44 -08001365handle_newline:
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001366 set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags);
Peter Hurley6d76bd22013-06-15 09:14:26 -04001367 put_tty_queue(c, ldata);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001368 ldata->canon_head = ldata->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
1370 if (waitqueue_active(&tty->read_wait))
1371 wake_up_interruptible(&tty->read_wait);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001372 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001373 }
1374 }
Alan Cox4edf1822008-02-08 04:18:44 -08001375
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
Peter Hurley001ba922013-12-02 14:24:44 -05001389 /* PARMRK doubling check */
1390 if (c == (unsigned char) '\377' && I_PARMRK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001391 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392
Jiri Slaby57c94122012-10-18 22:26:43 +02001393 put_tty_queue(c, ldata);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001394 return 0;
Alan Cox4edf1822008-02-08 04:18:44 -08001395}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001396
Peter Hurleye60d27c2013-07-24 08:29:56 -04001397static inline void
1398n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c)
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001399{
1400 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001401
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 }
Peter Hurley001ba922013-12-02 14:24:44 -05001414 /* PARMRK doubling check */
1415 if (c == (unsigned char) '\377' && I_PARMRK(tty))
Peter Hurleye60d27c2013-07-24 08:29:56 -04001416 put_tty_queue(c, ldata);
1417 put_tty_queue(c, ldata);
1418}
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001419
Peter Hurleyeb3e4662013-12-02 14:24:42 -05001420static void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
Peter Hurleye60d27c2013-07-24 08:29:56 -04001421{
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
Peter Hurley8dc4b252013-12-02 14:24:43 -05001445static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c)
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001446{
1447 if (I_ISTRIP(tty))
1448 c &= 0x7f;
1449 if (I_IUCLC(tty) && L_IEXTEN(tty))
1450 c = tolower(c);
1451
1452 if (I_IXON(tty)) {
1453 if (c == STOP_CHAR(tty))
1454 stop_tty(tty);
1455 else if (c == START_CHAR(tty) ||
1456 (tty->stopped && !tty->flow_stopped && I_IXANY(tty) &&
1457 c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) &&
1458 c != SUSP_CHAR(tty))) {
1459 start_tty(tty);
1460 process_echoes(tty);
1461 }
1462 }
1463}
1464
Peter Hurleyd2f8d7a2013-06-15 10:21:24 -04001465static void
1466n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag)
1467{
1468 char buf[64];
1469
1470 switch (flag) {
1471 case TTY_BREAK:
1472 n_tty_receive_break(tty);
1473 break;
1474 case TTY_PARITY:
1475 case TTY_FRAME:
1476 n_tty_receive_parity_error(tty, c);
1477 break;
1478 case TTY_OVERRUN:
1479 n_tty_receive_overrun(tty);
1480 break;
1481 default:
1482 printk(KERN_ERR "%s: unknown flag %d\n",
1483 tty_name(tty, buf), flag);
1484 break;
1485 }
1486}
1487
Peter Hurleye60d27c2013-07-24 08:29:56 -04001488static void
1489n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag)
1490{
1491 struct n_tty_data *ldata = tty->disc_data;
1492
1493 ldata->lnext = 0;
1494 if (likely(flag == TTY_NORMAL)) {
1495 if (I_ISTRIP(tty))
1496 c &= 0x7f;
1497 if (I_IUCLC(tty) && L_IEXTEN(tty))
1498 c = tolower(c);
1499 n_tty_receive_char(tty, c);
1500 } else
1501 n_tty_receive_char_flagged(tty, c, flag);
1502}
1503
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504/**
1505 * n_tty_receive_buf - data receive
1506 * @tty: terminal device
1507 * @cp: buffer
1508 * @fp: flag buffer
1509 * @count: characters
1510 *
1511 * Called by the terminal driver when a block of characters has
1512 * been received. This function must be called from soft contexts
1513 * not from interrupt context. The driver is responsible for making
1514 * calls one at a time and in order (or using flush_to_ldisc)
Peter Hurley6d76bd22013-06-15 09:14:26 -04001515 *
1516 * n_tty_receive_buf()/producer path:
1517 * claims non-exclusive termios_rwsem
1518 * publishes read_head and canon_head
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519 */
Alan Cox4edf1822008-02-08 04:18:44 -08001520
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001521static void
1522n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp,
1523 char *fp, int count)
1524{
1525 struct n_tty_data *ldata = tty->disc_data;
1526 size_t n, head;
1527
1528 head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
1529 n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head);
1530 n = min_t(size_t, count, n);
1531 memcpy(read_buf_addr(ldata, head), cp, n);
1532 ldata->read_head += n;
1533 cp += n;
1534 count -= n;
1535
1536 head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
1537 n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head);
1538 n = min_t(size_t, count, n);
1539 memcpy(read_buf_addr(ldata, head), cp, n);
1540 ldata->read_head += n;
1541}
1542
Peter Hurley554117b2013-06-15 10:21:25 -04001543static void
1544n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp,
1545 char *fp, int count)
1546{
1547 struct n_tty_data *ldata = tty->disc_data;
1548 char flag = TTY_NORMAL;
1549
1550 while (count--) {
1551 if (fp)
1552 flag = *fp++;
1553 if (likely(flag == TTY_NORMAL))
1554 put_tty_queue(*cp++, ldata);
1555 else
1556 n_tty_receive_char_flagged(tty, *cp++, flag);
1557 }
1558}
1559
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001560static void
1561n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp,
1562 char *fp, int count)
1563{
1564 char flag = TTY_NORMAL;
1565
1566 while (count--) {
1567 if (fp)
1568 flag = *fp++;
1569 if (likely(flag == TTY_NORMAL))
1570 n_tty_receive_char_closing(tty, *cp++);
1571 else
1572 n_tty_receive_char_flagged(tty, *cp++, flag);
1573 }
1574}
1575
Peter Hurley7d88d632013-07-24 08:29:49 -04001576static void
1577n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp,
Peter Hurley6baad002013-07-24 08:29:52 -04001578 char *fp, int count)
1579{
1580 struct n_tty_data *ldata = tty->disc_data;
1581 char flag = TTY_NORMAL;
1582
1583 while (count--) {
1584 if (fp)
1585 flag = *fp++;
1586 if (likely(flag == TTY_NORMAL)) {
1587 unsigned char c = *cp++;
1588
1589 if (I_ISTRIP(tty))
1590 c &= 0x7f;
1591 if (I_IUCLC(tty) && L_IEXTEN(tty))
1592 c = tolower(c);
1593 if (L_EXTPROC(tty)) {
1594 put_tty_queue(c, ldata);
1595 continue;
1596 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001597 if (!test_bit(c, ldata->char_map))
1598 n_tty_receive_char_inline(tty, c);
1599 else if (n_tty_receive_char_special(tty, c) && count) {
1600 if (fp)
1601 flag = *fp++;
1602 n_tty_receive_char_lnext(tty, *cp++, flag);
1603 count--;
1604 }
Peter Hurley6baad002013-07-24 08:29:52 -04001605 } else
1606 n_tty_receive_char_flagged(tty, *cp++, flag);
1607 }
1608}
1609
1610static void
1611n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp,
1612 char *fp, int count)
Peter Hurley7d88d632013-07-24 08:29:49 -04001613{
Peter Hurleye60d27c2013-07-24 08:29:56 -04001614 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley7d88d632013-07-24 08:29:49 -04001615 char flag = TTY_NORMAL;
1616
1617 while (count--) {
1618 if (fp)
1619 flag = *fp++;
Peter Hurleye60d27c2013-07-24 08:29:56 -04001620 if (likely(flag == TTY_NORMAL)) {
1621 unsigned char c = *cp++;
1622
1623 if (!test_bit(c, ldata->char_map))
1624 n_tty_receive_char_fast(tty, c);
1625 else if (n_tty_receive_char_special(tty, c) && count) {
1626 if (fp)
1627 flag = *fp++;
1628 n_tty_receive_char_lnext(tty, *cp++, flag);
1629 count--;
1630 }
1631 } else
Peter Hurley7d88d632013-07-24 08:29:49 -04001632 n_tty_receive_char_flagged(tty, *cp++, flag);
1633 }
1634}
1635
Peter Hurley24a89d12013-06-15 09:14:15 -04001636static void __receive_buf(struct tty_struct *tty, const unsigned char *cp,
1637 char *fp, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001639 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleya1dd30e2013-06-15 10:21:26 -04001640 bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001641
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001642 if (ldata->real_raw)
1643 n_tty_receive_buf_real_raw(tty, cp, fp, count);
Peter Hurleya1dd30e2013-06-15 10:21:26 -04001644 else if (ldata->raw || (L_EXTPROC(tty) && !preops))
Peter Hurley554117b2013-06-15 10:21:25 -04001645 n_tty_receive_buf_raw(tty, cp, fp, count);
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001646 else if (tty->closing && !L_EXTPROC(tty))
1647 n_tty_receive_buf_closing(tty, cp, fp, count);
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001648 else {
Peter Hurleye60d27c2013-07-24 08:29:56 -04001649 if (ldata->lnext) {
1650 char flag = TTY_NORMAL;
1651
1652 if (fp)
1653 flag = *fp++;
1654 n_tty_receive_char_lnext(tty, *cp++, flag);
1655 count--;
1656 }
1657
Peter Hurley7de971b2013-07-24 08:29:53 -04001658 if (!preops && !I_PARMRK(tty))
Peter Hurley6baad002013-07-24 08:29:52 -04001659 n_tty_receive_buf_fast(tty, cp, fp, count);
1660 else
1661 n_tty_receive_buf_standard(tty, cp, fp, count);
Peter Hurleycbfd0342013-06-15 10:04:26 -04001662
1663 flush_echoes(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001664 if (tty->ops->flush_chars)
1665 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666 }
1667
Peter Hurleyce741172013-06-15 09:14:20 -04001668 if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) ||
hyc@symas.com26df6d12010-06-22 10:14:49 -07001669 L_EXTPROC(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001670 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
1671 if (waitqueue_active(&tty->read_wait))
1672 wake_up_interruptible(&tty->read_wait);
1673 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001674}
1675
Peter Hurley5c32d122013-12-02 14:24:41 -05001676static int
1677n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
1678 char *fp, int count, int flow)
Peter Hurley24a89d12013-06-15 09:14:15 -04001679{
1680 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley19e2ad62013-07-24 08:29:54 -04001681 int room, n, rcvd = 0;
Peter Hurley24a89d12013-06-15 09:14:15 -04001682
Peter Hurley9356b532013-06-15 09:14:24 -04001683 down_read(&tty->termios_rwsem);
1684
Peter Hurley19e2ad62013-07-24 08:29:54 -04001685 while (1) {
1686 room = receive_room(tty);
1687 n = min(count, room);
1688 if (!n) {
Peter Hurley5c32d122013-12-02 14:24:41 -05001689 if (flow && !room)
Peter Hurley19e2ad62013-07-24 08:29:54 -04001690 ldata->no_room = 1;
1691 break;
1692 }
1693 __receive_buf(tty, cp, fp, n);
1694 cp += n;
1695 if (fp)
1696 fp += n;
1697 count -= n;
1698 rcvd += n;
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001699 }
Peter Hurley24a89d12013-06-15 09:14:15 -04001700
Peter Hurley19e2ad62013-07-24 08:29:54 -04001701 tty->receive_room = room;
1702 n_tty_check_throttle(tty);
Peter Hurley9356b532013-06-15 09:14:24 -04001703 up_read(&tty->termios_rwsem);
1704
Peter Hurley19e2ad62013-07-24 08:29:54 -04001705 return rcvd;
Peter Hurley24a89d12013-06-15 09:14:15 -04001706}
1707
Peter Hurley5c32d122013-12-02 14:24:41 -05001708static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1709 char *fp, int count)
1710{
1711 n_tty_receive_buf_common(tty, cp, fp, count, 0);
1712}
1713
1714static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp,
1715 char *fp, int count)
1716{
1717 return n_tty_receive_buf_common(tty, cp, fp, count, 1);
1718}
1719
Linus Torvalds1da177e2005-04-16 15:20:36 -07001720int is_ignored(int sig)
1721{
1722 return (sigismember(&current->blocked, sig) ||
Alan Cox4edf1822008-02-08 04:18:44 -08001723 current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001724}
1725
1726/**
1727 * n_tty_set_termios - termios data changed
1728 * @tty: terminal
1729 * @old: previous data
1730 *
1731 * Called by the tty layer when the user changes termios flags so
1732 * that the line discipline can plan ahead. This function cannot sleep
Alan Cox4edf1822008-02-08 04:18:44 -08001733 * and is protected from re-entry by the tty layer. The user is
Linus Torvalds1da177e2005-04-16 15:20:36 -07001734 * guaranteed that this function will not be re-entered or in progress
1735 * when the ldisc is closed.
Alan Cox17b82062008-10-13 10:45:06 +01001736 *
Peter Hurley6a1c0682013-06-15 09:14:23 -04001737 * Locking: Caller holds tty->termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001738 */
Alan Cox4edf1822008-02-08 04:18:44 -08001739
1740static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001741{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001742 struct n_tty_data *ldata = tty->disc_data;
Alan Cox47afa7a2008-10-13 10:44:17 +01001743
Peter Hurleyc786f742013-09-17 12:53:35 -04001744 if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) {
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001745 bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
Peter Hurley93a8d412013-09-17 12:34:14 -04001746 ldata->line_start = ldata->canon_head = ldata->read_tail;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001747 ldata->erasing = 0;
Peter Hurley6f9b0282013-06-15 09:14:27 -04001748 ldata->lnext = 0;
Alan Cox47afa7a2008-10-13 10:44:17 +01001749 }
1750
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001751 ldata->icanon = (L_ICANON(tty) != 0);
Peter Hurley582f5592013-05-17 12:49:48 -04001752
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753 if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
1754 I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
1755 I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
1756 I_PARMRK(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001757 bitmap_zero(ldata->char_map, 256);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001758
1759 if (I_IGNCR(tty) || I_ICRNL(tty))
Peter Hurley1bb9d562013-06-15 10:21:20 -04001760 set_bit('\r', ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761 if (I_INLCR(tty))
Peter Hurley1bb9d562013-06-15 10:21:20 -04001762 set_bit('\n', ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001763
1764 if (L_ICANON(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001765 set_bit(ERASE_CHAR(tty), ldata->char_map);
1766 set_bit(KILL_CHAR(tty), ldata->char_map);
1767 set_bit(EOF_CHAR(tty), ldata->char_map);
1768 set_bit('\n', ldata->char_map);
1769 set_bit(EOL_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001770 if (L_IEXTEN(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001771 set_bit(WERASE_CHAR(tty), ldata->char_map);
1772 set_bit(LNEXT_CHAR(tty), ldata->char_map);
1773 set_bit(EOL2_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001774 if (L_ECHO(tty))
1775 set_bit(REPRINT_CHAR(tty),
Peter Hurley1bb9d562013-06-15 10:21:20 -04001776 ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001777 }
1778 }
1779 if (I_IXON(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001780 set_bit(START_CHAR(tty), ldata->char_map);
1781 set_bit(STOP_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001782 }
1783 if (L_ISIG(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001784 set_bit(INTR_CHAR(tty), ldata->char_map);
1785 set_bit(QUIT_CHAR(tty), ldata->char_map);
1786 set_bit(SUSP_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787 }
Peter Hurley1bb9d562013-06-15 10:21:20 -04001788 clear_bit(__DISABLED_CHAR, ldata->char_map);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001789 ldata->raw = 0;
1790 ldata->real_raw = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791 } else {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001792 ldata->raw = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001793 if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
1794 (I_IGNPAR(tty) || !I_INPCK(tty)) &&
1795 (tty->driver->flags & TTY_DRIVER_REAL_RAW))
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001796 ldata->real_raw = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001797 else
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001798 ldata->real_raw = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 }
Linus Torvalds55db4c62011-06-04 06:33:24 +09001800 n_tty_set_room(tty);
Wang YanQingdab73b42013-05-09 14:16:47 +08001801 /*
1802 * Fix tty hang when I_IXON(tty) is cleared, but the tty
1803 * been stopped by STOP_CHAR(tty) before it.
1804 */
Peter Hurley103fcbe22013-09-17 12:53:36 -04001805 if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped)
Wang YanQingdab73b42013-05-09 14:16:47 +08001806 start_tty(tty);
Wang YanQingdab73b42013-05-09 14:16:47 +08001807
Alan Coxf34d7a52008-04-30 00:54:13 -07001808 /* The termios change make the tty ready for I/O */
Peter Hurley6c677162013-12-02 14:24:46 -05001809 if (waitqueue_active(&tty->write_wait))
1810 wake_up_interruptible(&tty->write_wait);
1811 if (waitqueue_active(&tty->read_wait))
1812 wake_up_interruptible(&tty->read_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001813}
1814
1815/**
1816 * n_tty_close - close the ldisc for this tty
1817 * @tty: device
1818 *
Alan Cox4edf1822008-02-08 04:18:44 -08001819 * Called from the terminal layer when this line discipline is
1820 * being shut down, either because of a close or becsuse of a
Linus Torvalds1da177e2005-04-16 15:20:36 -07001821 * discipline change. The function will not be called while other
1822 * ldisc methods are in progress.
1823 */
Alan Cox4edf1822008-02-08 04:18:44 -08001824
Linus Torvalds1da177e2005-04-16 15:20:36 -07001825static void n_tty_close(struct tty_struct *tty)
1826{
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001827 struct n_tty_data *ldata = tty->disc_data;
1828
Peter Hurley79901312013-03-11 16:44:23 -04001829 if (tty->link)
1830 n_tty_packet_mode_flush(tty);
1831
Peter Hurley20bafb32013-06-15 10:21:19 -04001832 vfree(ldata);
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001833 tty->disc_data = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834}
1835
1836/**
1837 * n_tty_open - open an ldisc
1838 * @tty: terminal to open
1839 *
Alan Cox4edf1822008-02-08 04:18:44 -08001840 * Called when this line discipline is being attached to the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001841 * terminal device. Can sleep. Called serialized so that no
1842 * other events will occur in parallel. No further open will occur
1843 * until a close.
1844 */
1845
1846static int n_tty_open(struct tty_struct *tty)
1847{
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001848 struct n_tty_data *ldata;
1849
Peter Hurley20bafb32013-06-15 10:21:19 -04001850 /* Currently a malloc failure here can panic */
1851 ldata = vmalloc(sizeof(*ldata));
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001852 if (!ldata)
1853 goto err;
1854
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001855 ldata->overrun_time = jiffies;
Jiri Slabybddc7152012-10-18 22:26:42 +02001856 mutex_init(&ldata->atomic_read_lock);
1857 mutex_init(&ldata->output_lock);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001858
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001859 tty->disc_data = ldata;
Peter Hurleyb66f4fa2013-03-11 16:44:32 -04001860 reset_buffer_flags(tty->disc_data);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001861 ldata->column = 0;
Peter Hurley20bafb32013-06-15 10:21:19 -04001862 ldata->canon_column = 0;
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04001863 ldata->minimum_to_wake = 1;
Peter Hurley20bafb32013-06-15 10:21:19 -04001864 ldata->num_overrun = 0;
1865 ldata->no_room = 0;
1866 ldata->lnext = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867 tty->closing = 0;
Peter Hurleyb66f4fa2013-03-11 16:44:32 -04001868 /* indicate buffer work may resume */
1869 clear_bit(TTY_LDISC_HALTED, &tty->flags);
1870 n_tty_set_termios(tty, NULL);
1871 tty_unthrottle(tty);
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001872
Linus Torvalds1da177e2005-04-16 15:20:36 -07001873 return 0;
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001874err:
Jiri Slabyb91939f2012-10-18 22:26:35 +02001875 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001876}
1877
Peter Hurleyeafbe672013-12-02 14:24:45 -05001878static inline int input_available_p(struct tty_struct *tty, int poll)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001879{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001880 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleyeafbe672013-12-02 14:24:45 -05001881 int amt = poll && !TIME_CHAR(tty) ? MIN_CHAR(tty) : 1;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001882
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001883 if (ldata->icanon && !L_EXTPROC(tty)) {
Peter Hurleya73d3d62013-06-15 09:14:25 -04001884 if (ldata->canon_head != ldata->read_tail)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885 return 1;
Peter Hurleyeafbe672013-12-02 14:24:45 -05001886 } else if (read_cnt(ldata) >= amt)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001887 return 1;
1888
1889 return 0;
1890}
1891
1892/**
Thorsten Wißmannbbd20752011-12-08 17:47:33 +01001893 * copy_from_read_buf - copy read data directly
Linus Torvalds1da177e2005-04-16 15:20:36 -07001894 * @tty: terminal device
1895 * @b: user data
1896 * @nr: size of data
1897 *
Alan Cox11a96d12008-10-13 10:46:24 +01001898 * Helper function to speed up n_tty_read. It is only called when
Linus Torvalds1da177e2005-04-16 15:20:36 -07001899 * ICANON is off; it copies characters straight from the tty queue to
1900 * user space directly. It can be profitably called twice; once to
1901 * drain the space from the tail pointer to the (physical) end of the
1902 * buffer, and once to drain the space from the (physical) beginning of
1903 * the buffer to head pointer.
1904 *
Jiri Slabybddc7152012-10-18 22:26:42 +02001905 * Called under the ldata->atomic_read_lock sem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001906 *
Peter Hurley6d76bd22013-06-15 09:14:26 -04001907 * n_tty_read()/consumer path:
1908 * caller holds non-exclusive termios_rwsem
1909 * read_tail published
Linus Torvalds1da177e2005-04-16 15:20:36 -07001910 */
Alan Cox4edf1822008-02-08 04:18:44 -08001911
Alan Cox33f0f882006-01-09 20:54:13 -08001912static int copy_from_read_buf(struct tty_struct *tty,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001913 unsigned char __user **b,
1914 size_t *nr)
1915
1916{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001917 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001918 int retval;
1919 size_t n;
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02001920 bool is_eof;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001921 size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922
1923 retval = 0;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001924 n = min(read_cnt(ldata), N_TTY_BUF_SIZE - tail);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001925 n = min(*nr, n);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001926 if (n) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001927 retval = copy_to_user(*b, read_buf_addr(ldata, tail), n);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001928 n -= retval;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001929 is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty);
1930 tty_audit_add_data(tty, read_buf_addr(ldata, tail), n,
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001931 ldata->icanon);
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001932 ldata->read_tail += n;
hyc@symas.com26df6d12010-06-22 10:14:49 -07001933 /* Turn single EOF into zero-length read */
Peter Hurleyce741172013-06-15 09:14:20 -04001934 if (L_EXTPROC(tty) && ldata->icanon && is_eof && !read_cnt(ldata))
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02001935 n = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001936 *b += n;
1937 *nr -= n;
1938 }
1939 return retval;
1940}
1941
Peter Hurley88bb0de2013-06-15 09:14:16 -04001942/**
Peter Hurley32f13522013-06-15 09:14:17 -04001943 * canon_copy_from_read_buf - copy read data in canonical mode
Peter Hurley88bb0de2013-06-15 09:14:16 -04001944 * @tty: terminal device
1945 * @b: user data
1946 * @nr: size of data
1947 *
1948 * Helper function for n_tty_read. It is only called when ICANON is on;
Peter Hurley32f13522013-06-15 09:14:17 -04001949 * it copies one line of input up to and including the line-delimiting
1950 * character into the user-space buffer.
Peter Hurley88bb0de2013-06-15 09:14:16 -04001951 *
1952 * Called under the atomic_read_lock mutex
Peter Hurley6d76bd22013-06-15 09:14:26 -04001953 *
1954 * n_tty_read()/consumer path:
1955 * caller holds non-exclusive termios_rwsem
1956 * read_tail published
Peter Hurley88bb0de2013-06-15 09:14:16 -04001957 */
1958
Peter Hurley32f13522013-06-15 09:14:17 -04001959static int canon_copy_from_read_buf(struct tty_struct *tty,
1960 unsigned char __user **b,
1961 size_t *nr)
Peter Hurley88bb0de2013-06-15 09:14:16 -04001962{
1963 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley32f13522013-06-15 09:14:17 -04001964 size_t n, size, more, c;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001965 size_t eol;
1966 size_t tail;
1967 int ret, found = 0;
Peter Hurley40d5e092013-06-15 10:21:17 -04001968 bool eof_push = 0;
Peter Hurley88bb0de2013-06-15 09:14:16 -04001969
1970 /* N.B. avoid overrun if nr == 0 */
Peter Hurleyce741172013-06-15 09:14:20 -04001971 n = min(*nr, read_cnt(ldata));
Peter Hurley6d76bd22013-06-15 09:14:26 -04001972 if (!n)
Peter Hurley32f13522013-06-15 09:14:17 -04001973 return 0;
Peter Hurley88bb0de2013-06-15 09:14:16 -04001974
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001975 tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
Peter Hurley32f13522013-06-15 09:14:17 -04001976 size = min_t(size_t, tail + n, N_TTY_BUF_SIZE);
1977
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001978 n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n",
Peter Hurley32f13522013-06-15 09:14:17 -04001979 __func__, *nr, tail, n, size);
1980
1981 eol = find_next_bit(ldata->read_flags, size, tail);
1982 more = n - (size - tail);
1983 if (eol == N_TTY_BUF_SIZE && more) {
1984 /* scan wrapped without finding set bit */
1985 eol = find_next_bit(ldata->read_flags, more, 0);
1986 if (eol != more)
1987 found = 1;
1988 } else if (eol != size)
1989 found = 1;
1990
1991 size = N_TTY_BUF_SIZE - tail;
Peter Hurleyc77569d2013-11-22 07:16:25 -05001992 n = eol - tail;
1993 if (n > 4096)
1994 n += 4096;
1995 n += found;
Peter Hurley32f13522013-06-15 09:14:17 -04001996 c = n;
1997
Peter Hurley40d5e092013-06-15 10:21:17 -04001998 if (found && read_buf(ldata, eol) == __DISABLED_CHAR) {
Peter Hurley32f13522013-06-15 09:14:17 -04001999 n--;
Peter Hurley40d5e092013-06-15 10:21:17 -04002000 eof_push = !n && ldata->read_tail != ldata->line_start;
2001 }
Peter Hurley32f13522013-06-15 09:14:17 -04002002
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002003 n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n",
Peter Hurley32f13522013-06-15 09:14:17 -04002004 __func__, eol, found, n, c, size, more);
2005
Peter Hurley32f13522013-06-15 09:14:17 -04002006 if (n > size) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002007 ret = copy_to_user(*b, read_buf_addr(ldata, tail), size);
Peter Hurley32f13522013-06-15 09:14:17 -04002008 if (ret)
2009 return -EFAULT;
2010 ret = copy_to_user(*b + size, ldata->read_buf, n - size);
2011 } else
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002012 ret = copy_to_user(*b, read_buf_addr(ldata, tail), n);
Peter Hurley32f13522013-06-15 09:14:17 -04002013
2014 if (ret)
2015 return -EFAULT;
2016 *b += n;
2017 *nr -= n;
2018
Peter Hurleya73d3d62013-06-15 09:14:25 -04002019 if (found)
Peter Hurley6d76bd22013-06-15 09:14:26 -04002020 clear_bit(eol, ldata->read_flags);
2021 smp_mb__after_clear_bit();
2022 ldata->read_tail += c;
Peter Hurley88bb0de2013-06-15 09:14:16 -04002023
Peter Hurley40d5e092013-06-15 10:21:17 -04002024 if (found) {
2025 ldata->line_start = ldata->read_tail;
Peter Hurley32f13522013-06-15 09:14:17 -04002026 tty_audit_push(tty);
Peter Hurley40d5e092013-06-15 10:21:17 -04002027 }
2028 return eof_push ? -EAGAIN : 0;
Peter Hurley88bb0de2013-06-15 09:14:16 -04002029}
2030
Al Virocc4191d2008-03-29 03:08:48 +00002031extern ssize_t redirected_tty_write(struct file *, const char __user *,
Alan Cox4edf1822008-02-08 04:18:44 -08002032 size_t, loff_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002033
2034/**
2035 * job_control - check job control
2036 * @tty: tty
2037 * @file: file handle
2038 *
2039 * Perform job control management checks on this file/tty descriptor
Alan Cox4edf1822008-02-08 04:18:44 -08002040 * and if appropriate send any needed signals and return a negative
Linus Torvalds1da177e2005-04-16 15:20:36 -07002041 * error code if action should be taken.
Alan Cox04f378b2008-04-30 00:53:29 -07002042 *
Peter Hurley01a5e442013-03-06 08:38:20 -05002043 * Locking: redirected write test is safe
2044 * current->signal->tty check is safe
2045 * ctrl_lock to safely reference tty->pgrp
Linus Torvalds1da177e2005-04-16 15:20:36 -07002046 */
Alan Cox4edf1822008-02-08 04:18:44 -08002047
Linus Torvalds1da177e2005-04-16 15:20:36 -07002048static int job_control(struct tty_struct *tty, struct file *file)
2049{
2050 /* Job control check -- must be done at start and after
2051 every sleep (POSIX.1 7.1.1.4). */
2052 /* NOTE: not yet done after every sleep pending a thorough
2053 check of the logic of this change. -- jlc */
2054 /* don't stop on /dev/console */
Peter Hurley01a5e442013-03-06 08:38:20 -05002055 if (file->f_op->write == redirected_tty_write ||
2056 current->signal->tty != tty)
2057 return 0;
2058
2059 spin_lock_irq(&tty->ctrl_lock);
2060 if (!tty->pgrp)
2061 printk(KERN_ERR "n_tty_read: no tty->pgrp!\n");
2062 else if (task_pgrp(current) != tty->pgrp) {
2063 spin_unlock_irq(&tty->ctrl_lock);
2064 if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned())
2065 return -EIO;
2066 kill_pgrp(task_pgrp(current), SIGTTIN, 1);
2067 set_thread_flag(TIF_SIGPENDING);
2068 return -ERESTARTSYS;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002069 }
Peter Hurley01a5e442013-03-06 08:38:20 -05002070 spin_unlock_irq(&tty->ctrl_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002071 return 0;
2072}
Alan Cox4edf1822008-02-08 04:18:44 -08002073
Linus Torvalds1da177e2005-04-16 15:20:36 -07002074
2075/**
Alan Cox11a96d12008-10-13 10:46:24 +01002076 * n_tty_read - read function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07002077 * @tty: tty device
2078 * @file: file object
2079 * @buf: userspace buffer pointer
2080 * @nr: size of I/O
2081 *
2082 * Perform reads for the line discipline. We are guaranteed that the
2083 * line discipline will not be closed under us but we may get multiple
2084 * parallel readers and must handle this ourselves. We may also get
2085 * a hangup. Always called in user context, may sleep.
2086 *
2087 * This code must be sure never to sleep through a hangup.
Peter Hurley6d76bd22013-06-15 09:14:26 -04002088 *
2089 * n_tty_read()/consumer path:
2090 * claims non-exclusive termios_rwsem
2091 * publishes read_tail
Linus Torvalds1da177e2005-04-16 15:20:36 -07002092 */
Alan Cox4edf1822008-02-08 04:18:44 -08002093
Alan Cox11a96d12008-10-13 10:46:24 +01002094static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002095 unsigned char __user *buf, size_t nr)
2096{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002097 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002098 unsigned char __user *b = buf;
2099 DECLARE_WAITQUEUE(wait, current);
2100 int c;
2101 int minimum, time;
2102 ssize_t retval = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002103 long timeout;
2104 unsigned long flags;
Alan Cox04f378b2008-04-30 00:53:29 -07002105 int packet;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002106
Linus Torvalds1da177e2005-04-16 15:20:36 -07002107 c = job_control(tty, file);
Alan Cox4edf1822008-02-08 04:18:44 -08002108 if (c < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002109 return c;
Alan Cox4edf1822008-02-08 04:18:44 -08002110
Peter Hurleyaefceaf2013-08-11 08:04:23 -04002111 /*
2112 * Internal serialization of reads.
2113 */
2114 if (file->f_flags & O_NONBLOCK) {
2115 if (!mutex_trylock(&ldata->atomic_read_lock))
2116 return -EAGAIN;
2117 } else {
2118 if (mutex_lock_interruptible(&ldata->atomic_read_lock))
2119 return -ERESTARTSYS;
2120 }
2121
Peter Hurley9356b532013-06-15 09:14:24 -04002122 down_read(&tty->termios_rwsem);
2123
Linus Torvalds1da177e2005-04-16 15:20:36 -07002124 minimum = time = 0;
2125 timeout = MAX_SCHEDULE_TIMEOUT;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002126 if (!ldata->icanon) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002127 minimum = MIN_CHAR(tty);
2128 if (minimum) {
Peter Hurleya6e54312013-06-15 07:28:29 -04002129 time = (HZ / 10) * TIME_CHAR(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002130 if (time)
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002131 ldata->minimum_to_wake = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002132 else if (!waitqueue_active(&tty->read_wait) ||
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002133 (ldata->minimum_to_wake > minimum))
2134 ldata->minimum_to_wake = minimum;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002135 } else {
Peter Hurleya6e54312013-06-15 07:28:29 -04002136 timeout = (HZ / 10) * TIME_CHAR(tty);
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002137 ldata->minimum_to_wake = minimum = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002138 }
2139 }
2140
Alan Cox04f378b2008-04-30 00:53:29 -07002141 packet = tty->packet;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002142
2143 add_wait_queue(&tty->read_wait, &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002144 while (nr) {
2145 /* First test for status change. */
Alan Cox04f378b2008-04-30 00:53:29 -07002146 if (packet && tty->link->ctrl_status) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002147 unsigned char cs;
2148 if (b != buf)
2149 break;
Alan Cox04f378b2008-04-30 00:53:29 -07002150 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002151 cs = tty->link->ctrl_status;
2152 tty->link->ctrl_status = 0;
Alan Cox04f378b2008-04-30 00:53:29 -07002153 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
Miloslav Trmac522ed772007-07-15 23:40:56 -07002154 if (tty_put_user(tty, cs, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002155 retval = -EFAULT;
2156 b--;
2157 break;
2158 }
2159 nr--;
2160 break;
2161 }
2162 /* This statement must be first before checking for input
2163 so that any interrupt will set the state back to
2164 TASK_RUNNING. */
2165 set_current_state(TASK_INTERRUPTIBLE);
Alan Cox4edf1822008-02-08 04:18:44 -08002166
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002167 if (((minimum - (b - buf)) < ldata->minimum_to_wake) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07002168 ((minimum - (b - buf)) >= 1))
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002169 ldata->minimum_to_wake = (minimum - (b - buf));
Alan Cox4edf1822008-02-08 04:18:44 -08002170
Linus Torvalds1da177e2005-04-16 15:20:36 -07002171 if (!input_available_p(tty, 0)) {
2172 if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
Peter Hurleyf8747d42013-09-27 13:27:05 -04002173 up_read(&tty->termios_rwsem);
2174 tty_flush_to_ldisc(tty);
2175 down_read(&tty->termios_rwsem);
2176 if (!input_available_p(tty, 0)) {
2177 retval = -EIO;
2178 break;
2179 }
2180 } else {
2181 if (tty_hung_up_p(file))
2182 break;
2183 if (!timeout)
2184 break;
2185 if (file->f_flags & O_NONBLOCK) {
2186 retval = -EAGAIN;
2187 break;
2188 }
2189 if (signal_pending(current)) {
2190 retval = -ERESTARTSYS;
2191 break;
2192 }
2193 n_tty_set_room(tty);
2194 up_read(&tty->termios_rwsem);
Peter Hurley9356b532013-06-15 09:14:24 -04002195
Peter Hurleyf8747d42013-09-27 13:27:05 -04002196 timeout = schedule_timeout(timeout);
Peter Hurley9356b532013-06-15 09:14:24 -04002197
Peter Hurleyf8747d42013-09-27 13:27:05 -04002198 down_read(&tty->termios_rwsem);
2199 continue;
2200 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002201 }
2202 __set_current_state(TASK_RUNNING);
2203
2204 /* Deal with packet mode. */
Alan Cox04f378b2008-04-30 00:53:29 -07002205 if (packet && b == buf) {
Miloslav Trmac522ed772007-07-15 23:40:56 -07002206 if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002207 retval = -EFAULT;
2208 b--;
2209 break;
2210 }
2211 nr--;
2212 }
2213
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002214 if (ldata->icanon && !L_EXTPROC(tty)) {
Peter Hurley32f13522013-06-15 09:14:17 -04002215 retval = canon_copy_from_read_buf(tty, &b, &nr);
Peter Hurley40d5e092013-06-15 10:21:17 -04002216 if (retval == -EAGAIN) {
2217 retval = 0;
2218 continue;
2219 } else if (retval)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002220 break;
2221 } else {
2222 int uncopied;
Alan Cox04f378b2008-04-30 00:53:29 -07002223 /* The copy function takes the read lock and handles
2224 locking internally for this case */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002225 uncopied = copy_from_read_buf(tty, &b, &nr);
2226 uncopied += copy_from_read_buf(tty, &b, &nr);
2227 if (uncopied) {
2228 retval = -EFAULT;
2229 break;
2230 }
2231 }
2232
Peter Hurley6367ca72013-06-15 09:14:33 -04002233 n_tty_check_unthrottle(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002234
2235 if (b - buf >= minimum)
2236 break;
2237 if (time)
2238 timeout = time;
2239 }
Peter Hurley42458f42013-11-07 13:59:46 -05002240 n_tty_set_room(tty);
2241 up_read(&tty->termios_rwsem);
2242
Linus Torvalds1da177e2005-04-16 15:20:36 -07002243 remove_wait_queue(&tty->read_wait, &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002244 if (!waitqueue_active(&tty->read_wait))
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002245 ldata->minimum_to_wake = minimum;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002246
Peter Hurleyaebf04532013-11-07 14:01:57 -05002247 mutex_unlock(&ldata->atomic_read_lock);
2248
Linus Torvalds1da177e2005-04-16 15:20:36 -07002249 __set_current_state(TASK_RUNNING);
Peter Hurley40d5e092013-06-15 10:21:17 -04002250 if (b - buf)
2251 retval = b - buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002252
2253 return retval;
2254}
2255
2256/**
Alan Cox11a96d12008-10-13 10:46:24 +01002257 * n_tty_write - write function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07002258 * @tty: tty device
2259 * @file: file object
2260 * @buf: userspace buffer pointer
2261 * @nr: size of I/O
2262 *
Joe Petersona88a69c2009-01-02 13:40:53 +00002263 * Write function of the terminal device. This is serialized with
Linus Torvalds1da177e2005-04-16 15:20:36 -07002264 * respect to other write callers but not to termios changes, reads
Joe Petersona88a69c2009-01-02 13:40:53 +00002265 * and other such events. Since the receive code will echo characters,
2266 * thus calling driver write methods, the output_lock is used in
2267 * the output processing functions called here as well as in the
2268 * echo processing function to protect the column state and space
2269 * left in the buffer.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002270 *
2271 * This code must be sure never to sleep through a hangup.
Joe Petersona88a69c2009-01-02 13:40:53 +00002272 *
2273 * Locking: output_lock to protect column state and space left
2274 * (note that the process_output*() functions take this
2275 * lock themselves)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002276 */
Alan Cox4edf1822008-02-08 04:18:44 -08002277
Alan Cox11a96d12008-10-13 10:46:24 +01002278static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
Joe Petersona88a69c2009-01-02 13:40:53 +00002279 const unsigned char *buf, size_t nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002280{
2281 const unsigned char *b = buf;
2282 DECLARE_WAITQUEUE(wait, current);
2283 int c;
2284 ssize_t retval = 0;
2285
2286 /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
2287 if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) {
2288 retval = tty_check_change(tty);
2289 if (retval)
2290 return retval;
2291 }
2292
Peter Hurley9356b532013-06-15 09:14:24 -04002293 down_read(&tty->termios_rwsem);
2294
Joe Petersona88a69c2009-01-02 13:40:53 +00002295 /* Write out any echoed characters that are still pending */
2296 process_echoes(tty);
Alan Cox300a6202009-01-02 13:41:04 +00002297
Linus Torvalds1da177e2005-04-16 15:20:36 -07002298 add_wait_queue(&tty->write_wait, &wait);
2299 while (1) {
2300 set_current_state(TASK_INTERRUPTIBLE);
2301 if (signal_pending(current)) {
2302 retval = -ERESTARTSYS;
2303 break;
2304 }
2305 if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) {
2306 retval = -EIO;
2307 break;
2308 }
Peter Hurley582f5592013-05-17 12:49:48 -04002309 if (O_OPOST(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002310 while (nr > 0) {
Joe Petersona88a69c2009-01-02 13:40:53 +00002311 ssize_t num = process_output_block(tty, b, nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002312 if (num < 0) {
2313 if (num == -EAGAIN)
2314 break;
2315 retval = num;
2316 goto break_out;
2317 }
2318 b += num;
2319 nr -= num;
2320 if (nr == 0)
2321 break;
2322 c = *b;
Joe Petersona88a69c2009-01-02 13:40:53 +00002323 if (process_output(c, tty) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002324 break;
2325 b++; nr--;
2326 }
Alan Coxf34d7a52008-04-30 00:54:13 -07002327 if (tty->ops->flush_chars)
2328 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002329 } else {
Roman Zippeld6afe272005-07-07 17:56:55 -07002330 while (nr > 0) {
Alan Coxf34d7a52008-04-30 00:54:13 -07002331 c = tty->ops->write(tty, b, nr);
Roman Zippeld6afe272005-07-07 17:56:55 -07002332 if (c < 0) {
2333 retval = c;
2334 goto break_out;
2335 }
2336 if (!c)
2337 break;
2338 b += c;
2339 nr -= c;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002340 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002341 }
2342 if (!nr)
2343 break;
2344 if (file->f_flags & O_NONBLOCK) {
2345 retval = -EAGAIN;
2346 break;
2347 }
Peter Hurley9356b532013-06-15 09:14:24 -04002348 up_read(&tty->termios_rwsem);
2349
Linus Torvalds1da177e2005-04-16 15:20:36 -07002350 schedule();
Peter Hurley9356b532013-06-15 09:14:24 -04002351
2352 down_read(&tty->termios_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002353 }
2354break_out:
2355 __set_current_state(TASK_RUNNING);
2356 remove_wait_queue(&tty->write_wait, &wait);
Thomas Pfaffff8cb0f2009-01-02 13:47:13 +00002357 if (b - buf != nr && tty->fasync)
2358 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Peter Hurley9356b532013-06-15 09:14:24 -04002359 up_read(&tty->termios_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002360 return (b - buf) ? b - buf : retval;
2361}
2362
2363/**
Alan Cox11a96d12008-10-13 10:46:24 +01002364 * n_tty_poll - poll method for N_TTY
Linus Torvalds1da177e2005-04-16 15:20:36 -07002365 * @tty: terminal device
2366 * @file: file accessing it
2367 * @wait: poll table
2368 *
2369 * Called when the line discipline is asked to poll() for data or
2370 * for special events. This code is not serialized with respect to
2371 * other events save open/close.
2372 *
2373 * This code must be sure never to sleep through a hangup.
2374 * Called without the kernel lock held - fine
Linus Torvalds1da177e2005-04-16 15:20:36 -07002375 */
Alan Cox4edf1822008-02-08 04:18:44 -08002376
Alan Cox11a96d12008-10-13 10:46:24 +01002377static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
Alan Cox4edf1822008-02-08 04:18:44 -08002378 poll_table *wait)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002379{
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002380 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002381 unsigned int mask = 0;
2382
2383 poll_wait(file, &tty->read_wait, wait);
2384 poll_wait(file, &tty->write_wait, wait);
Peter Hurleyeafbe672013-12-02 14:24:45 -05002385 if (input_available_p(tty, 1))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002386 mask |= POLLIN | POLLRDNORM;
2387 if (tty->packet && tty->link->ctrl_status)
2388 mask |= POLLPRI | POLLIN | POLLRDNORM;
2389 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
2390 mask |= POLLHUP;
2391 if (tty_hung_up_p(file))
2392 mask |= POLLHUP;
2393 if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) {
2394 if (MIN_CHAR(tty) && !TIME_CHAR(tty))
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002395 ldata->minimum_to_wake = MIN_CHAR(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002396 else
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002397 ldata->minimum_to_wake = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002398 }
Alan Coxf34d7a52008-04-30 00:54:13 -07002399 if (tty->ops->write && !tty_is_writelocked(tty) &&
2400 tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
2401 tty_write_room(tty) > 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002402 mask |= POLLOUT | POLLWRNORM;
2403 return mask;
2404}
2405
Jiri Slaby57c94122012-10-18 22:26:43 +02002406static unsigned long inq_canon(struct n_tty_data *ldata)
Alan Cox47afa7a2008-10-13 10:44:17 +01002407{
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002408 size_t nr, head, tail;
Alan Cox47afa7a2008-10-13 10:44:17 +01002409
Peter Hurleya73d3d62013-06-15 09:14:25 -04002410 if (ldata->canon_head == ldata->read_tail)
Alan Cox47afa7a2008-10-13 10:44:17 +01002411 return 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002412 head = ldata->canon_head;
2413 tail = ldata->read_tail;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002414 nr = head - tail;
Alan Cox47afa7a2008-10-13 10:44:17 +01002415 /* Skip EOF-chars.. */
2416 while (head != tail) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002417 if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) &&
2418 read_buf(ldata, tail) == __DISABLED_CHAR)
Alan Cox47afa7a2008-10-13 10:44:17 +01002419 nr--;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002420 tail++;
Alan Cox47afa7a2008-10-13 10:44:17 +01002421 }
2422 return nr;
2423}
2424
2425static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
2426 unsigned int cmd, unsigned long arg)
2427{
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002428 struct n_tty_data *ldata = tty->disc_data;
Alan Cox47afa7a2008-10-13 10:44:17 +01002429 int retval;
2430
2431 switch (cmd) {
2432 case TIOCOUTQ:
2433 return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
2434 case TIOCINQ:
Peter Hurley6d76bd22013-06-15 09:14:26 -04002435 down_write(&tty->termios_rwsem);
Alan Cox47afa7a2008-10-13 10:44:17 +01002436 if (L_ICANON(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02002437 retval = inq_canon(ldata);
Peter Hurley6d76bd22013-06-15 09:14:26 -04002438 else
2439 retval = read_cnt(ldata);
2440 up_write(&tty->termios_rwsem);
Alan Cox47afa7a2008-10-13 10:44:17 +01002441 return put_user(retval, (unsigned int __user *) arg);
2442 default:
2443 return n_tty_ioctl_helper(tty, file, cmd, arg);
2444 }
2445}
2446
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002447static void n_tty_fasync(struct tty_struct *tty, int on)
2448{
2449 struct n_tty_data *ldata = tty->disc_data;
2450
2451 if (!waitqueue_active(&tty->read_wait)) {
2452 if (on)
2453 ldata->minimum_to_wake = 1;
2454 else if (!tty->fasync)
2455 ldata->minimum_to_wake = N_TTY_BUF_SIZE;
2456 }
2457}
2458
Alan Coxa352def2008-07-16 21:53:12 +01002459struct tty_ldisc_ops tty_ldisc_N_TTY = {
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002460 .magic = TTY_LDISC_MAGIC,
2461 .name = "n_tty",
2462 .open = n_tty_open,
2463 .close = n_tty_close,
2464 .flush_buffer = n_tty_flush_buffer,
2465 .chars_in_buffer = n_tty_chars_in_buffer,
Alan Cox11a96d12008-10-13 10:46:24 +01002466 .read = n_tty_read,
2467 .write = n_tty_write,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002468 .ioctl = n_tty_ioctl,
2469 .set_termios = n_tty_set_termios,
Alan Cox11a96d12008-10-13 10:46:24 +01002470 .poll = n_tty_poll,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002471 .receive_buf = n_tty_receive_buf,
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002472 .write_wakeup = n_tty_write_wakeup,
2473 .fasync = n_tty_fasync,
Peter Hurley24a89d12013-06-15 09:14:15 -04002474 .receive_buf2 = n_tty_receive_buf2,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002475};
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -08002476
2477/**
2478 * n_tty_inherit_ops - inherit N_TTY methods
2479 * @ops: struct tty_ldisc_ops where to save N_TTY methods
2480 *
George Spelvin593fb1ae42013-02-12 02:00:43 -05002481 * Enables a 'subclass' line discipline to 'inherit' N_TTY
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -08002482 * methods.
2483 */
2484
2485void n_tty_inherit_ops(struct tty_ldisc_ops *ops)
2486{
2487 *ops = tty_ldisc_N_TTY;
2488 ops->owner = NULL;
2489 ops->refcount = ops->flags = 0;
2490}
2491EXPORT_SYMBOL_GPL(n_tty_inherit_ops);