blob: 13844261cd5f3cdad44131a3e215f97d2ecae2f4 [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;
Peter Hurley70aca712015-01-16 15:05:37 -050093 size_t commit_head;
Peter Hurleyfb7aa032013-06-15 09:14:30 -040094 size_t canon_head;
Peter Hurley9dfd16d2013-06-15 10:04:29 -040095 size_t echo_head;
96 size_t echo_commit;
Peter Hurley1075a6e2013-12-09 18:06:07 -050097 size_t echo_mark;
Peter Hurley1bb9d562013-06-15 10:21:20 -040098 DECLARE_BITMAP(char_map, 256);
Peter Hurleyfb7aa032013-06-15 09:14:30 -040099
100 /* private to n_tty_receive_overrun (single-threaded) */
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200101 unsigned long overrun_time;
102 int num_overrun;
103
Peter Hurley24a89d12013-06-15 09:14:15 -0400104 /* non-atomic */
105 bool no_room;
106
Peter Hurleyfb7aa032013-06-15 09:14:30 -0400107 /* must hold exclusive termios_rwsem to reset these */
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200108 unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
Peter Hurley4d0ed182013-12-10 17:12:02 -0500109 unsigned char push:1;
Jiri Slaby3fe780b2012-10-18 22:26:40 +0200110
Peter Hurleyfb7aa032013-06-15 09:14:30 -0400111 /* shared by producer and consumer */
Peter Hurley20bafb32013-06-15 10:21:19 -0400112 char read_buf[N_TTY_BUF_SIZE];
Jiri Slaby3fe780b2012-10-18 22:26:40 +0200113 DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE);
Peter Hurley20bafb32013-06-15 10:21:19 -0400114 unsigned char echo_buf[N_TTY_BUF_SIZE];
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200115
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -0400116 int minimum_to_wake;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200117
Peter Hurleyfb7aa032013-06-15 09:14:30 -0400118 /* consumer-published */
119 size_t read_tail;
Peter Hurley40d5e092013-06-15 10:21:17 -0400120 size_t line_start;
Peter Hurleyfb7aa032013-06-15 09:14:30 -0400121
Peter Hurleyfb7aa032013-06-15 09:14:30 -0400122 /* protected by output lock */
123 unsigned int column;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200124 unsigned int canon_column;
Peter Hurley9dfd16d2013-06-15 10:04:29 -0400125 size_t echo_tail;
Jiri Slabybddc7152012-10-18 22:26:42 +0200126
127 struct mutex atomic_read_lock;
128 struct mutex output_lock;
Jiri Slaby70ece7a2012-10-18 22:26:38 +0200129};
130
Peter Hurleyce741172013-06-15 09:14:20 -0400131static inline size_t read_cnt(struct n_tty_data *ldata)
132{
Peter Hurleya2f73be2013-06-15 09:14:22 -0400133 return ldata->read_head - ldata->read_tail;
Peter Hurleyce741172013-06-15 09:14:20 -0400134}
135
Peter Hurleybc5a5e32013-06-15 09:14:21 -0400136static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i)
137{
138 return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)];
139}
140
141static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i)
142{
143 return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)];
144}
145
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400146static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i)
147{
148 return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
149}
150
151static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i)
152{
153 return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
154}
155
Miloslav Trmac522ed772007-07-15 23:40:56 -0700156static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
157 unsigned char __user *ptr)
158{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200159 struct n_tty_data *ldata = tty->disc_data;
160
161 tty_audit_add_data(tty, &x, 1, ldata->icanon);
Miloslav Trmac522ed772007-07-15 23:40:56 -0700162 return put_user(x, ptr);
163}
164
Laura Abbott72586c62015-05-14 11:42:17 -0700165static inline int tty_copy_to_user(struct tty_struct *tty,
166 void __user *to,
167 const void *from,
168 unsigned long n)
169{
170 struct n_tty_data *ldata = tty->disc_data;
171
172 tty_audit_add_data(tty, to, n, ldata->icanon);
173 return copy_to_user(to, from, n);
174}
175
Peter Hurley24a89d12013-06-15 09:14:15 -0400176/**
Peter Hurley2c5dc462015-01-16 15:05:34 -0500177 * n_tty_kick_worker - start input worker (if required)
Peter Hurley24a89d12013-06-15 09:14:15 -0400178 * @tty: terminal
179 *
Peter Hurley2c5dc462015-01-16 15:05:34 -0500180 * Re-schedules the flip buffer work if it may have stopped
Peter Hurley24a89d12013-06-15 09:14:15 -0400181 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400182 * Caller holds exclusive termios_rwsem
183 * or
184 * n_tty_read()/consumer path:
185 * holds non-exclusive termios_rwsem
Peter Hurley24a89d12013-06-15 09:14:15 -0400186 */
187
Peter Hurley2c5dc462015-01-16 15:05:34 -0500188static void n_tty_kick_worker(struct tty_struct *tty)
Peter Hurley7879a9f2013-06-15 07:28:31 -0400189{
Peter Hurley24a89d12013-06-15 09:14:15 -0400190 struct n_tty_data *ldata = tty->disc_data;
191
Peter Hurley2c5dc462015-01-16 15:05:34 -0500192 /* Did the input worker stop? Restart it */
193 if (unlikely(ldata->no_room)) {
Peter Hurley24a89d12013-06-15 09:14:15 -0400194 ldata->no_room = 0;
195
Jiri Slabyecbbfd42012-10-18 22:26:47 +0200196 WARN_RATELIMIT(tty->port->itty == NULL,
Sasha Levincadf7482012-10-25 14:26:35 -0400197 "scheduling with invalid itty\n");
Peter Hurley21622932013-03-11 16:44:21 -0400198 /* see if ldisc has been killed - if so, this means that
199 * even though the ldisc has been halted and ->buf.work
200 * cancelled, ->buf.work is about to be rescheduled
201 */
202 WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags),
203 "scheduling buffer work for halted ldisc\n");
Peter Hurleye1760582015-10-17 16:36:23 -0400204 tty_buffer_restart_work(tty->port);
Jiri Slabyecbbfd42012-10-18 22:26:47 +0200205 }
Linus Torvalds55db4c62011-06-04 06:33:24 +0900206}
207
Peter Hurley9a4aec22013-06-15 09:14:32 -0400208static ssize_t chars_in_buffer(struct tty_struct *tty)
209{
210 struct n_tty_data *ldata = tty->disc_data;
211 ssize_t n = 0;
212
213 if (!ldata->icanon)
Peter Hurley70aca712015-01-16 15:05:37 -0500214 n = ldata->commit_head - ldata->read_tail;
Peter Hurley9a4aec22013-06-15 09:14:32 -0400215 else
216 n = ldata->canon_head - ldata->read_tail;
217 return n;
218}
219
Peter Hurleyee0bab82013-06-15 09:14:34 -0400220/**
221 * n_tty_write_wakeup - asynchronous I/O notifier
222 * @tty: tty device
223 *
224 * Required for the ptys, serial driver etc. since processes
225 * that attach themselves to the master and rely on ASYNC
226 * IO must be woken up
227 */
228
229static void n_tty_write_wakeup(struct tty_struct *tty)
230{
231 if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags))
232 kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
233}
234
Peter Hurley4a23a4d2013-06-15 10:21:22 -0400235static void n_tty_check_throttle(struct tty_struct *tty)
Peter Hurley6367ca72013-06-15 09:14:33 -0400236{
Peter Hurleya3428462015-01-16 15:05:35 -0500237 struct n_tty_data *ldata = tty->disc_data;
238
Peter Hurley6367ca72013-06-15 09:14:33 -0400239 /*
240 * Check the remaining room for the input canonicalization
241 * mode. We don't want to throttle the driver if we're in
242 * canonical mode and don't have a newline yet!
243 */
Peter Hurleya3428462015-01-16 15:05:35 -0500244 if (ldata->icanon && ldata->canon_head == ldata->read_tail)
245 return;
246
Peter Hurley6367ca72013-06-15 09:14:33 -0400247 while (1) {
248 int throttled;
249 tty_set_flow_change(tty, TTY_THROTTLE_SAFE);
Peter Hurley5e28cca2015-01-16 15:05:36 -0500250 if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE)
Peter Hurley6367ca72013-06-15 09:14:33 -0400251 break;
252 throttled = tty_throttle_safe(tty);
253 if (!throttled)
254 break;
255 }
256 __tty_set_flow_change(tty, 0);
257}
258
Peter Hurley4b293492013-07-24 08:29:55 -0400259static void n_tty_check_unthrottle(struct tty_struct *tty)
Peter Hurley6367ca72013-06-15 09:14:33 -0400260{
Peter Hurley3afb1b392013-07-23 08:47:30 -0400261 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
262 tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) {
263 if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
264 return;
265 if (!tty->count)
266 return;
Peter Hurley2c5dc462015-01-16 15:05:34 -0500267 n_tty_kick_worker(tty);
Peter Hurley3afb1b392013-07-23 08:47:30 -0400268 n_tty_write_wakeup(tty->link);
Peter Hurley6c677162013-12-02 14:24:46 -0500269 if (waitqueue_active(&tty->link->write_wait))
270 wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT);
Peter Hurley3afb1b392013-07-23 08:47:30 -0400271 return;
272 }
273
Peter Hurley6367ca72013-06-15 09:14:33 -0400274 /* If there is enough space in the read buffer now, let the
275 * low-level driver know. We use chars_in_buffer() to
276 * check the buffer, as it now knows about canonical mode.
277 * Otherwise, if the driver is throttled and the line is
278 * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
279 * we won't get any more characters.
280 */
281
282 while (1) {
283 int unthrottled;
284 tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE);
285 if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
286 break;
287 if (!tty->count)
288 break;
Peter Hurley2c5dc462015-01-16 15:05:34 -0500289 n_tty_kick_worker(tty);
Peter Hurley6367ca72013-06-15 09:14:33 -0400290 unthrottled = tty_unthrottle_safe(tty);
291 if (!unthrottled)
292 break;
293 }
294 __tty_set_flow_change(tty, 0);
295}
296
Alan Cox17b82062008-10-13 10:45:06 +0100297/**
298 * put_tty_queue - add character to tty
299 * @c: character
Jiri Slaby57c94122012-10-18 22:26:43 +0200300 * @ldata: n_tty data
Alan Cox17b82062008-10-13 10:45:06 +0100301 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400302 * Add a character to the tty read_buf queue.
303 *
304 * n_tty_receive_buf()/producer path:
305 * caller holds non-exclusive termios_rwsem
Alan Cox17b82062008-10-13 10:45:06 +0100306 */
307
Peter Hurley19e2ad62013-07-24 08:29:54 -0400308static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309{
Christian Riesch8bfbe2d2014-11-13 05:53:26 +0100310 *read_buf_addr(ldata, ldata->read_head) = c;
311 ldata->read_head++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312}
313
314/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 * reset_buffer_flags - reset buffer state
316 * @tty: terminal to reset
317 *
Peter Hurley25518c62013-03-11 16:44:31 -0400318 * Reset the read buffer counters and clear the flags.
319 * Called from n_tty_open() and n_tty_flush_buffer().
Alan Cox17b82062008-10-13 10:45:06 +0100320 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400321 * Locking: caller holds exclusive termios_rwsem
322 * (or locking is not required)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000324
Peter Hurleyb66f4fa2013-03-11 16:44:32 -0400325static void reset_buffer_flags(struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326{
Peter Hurleya73d3d62013-06-15 09:14:25 -0400327 ldata->read_head = ldata->canon_head = ldata->read_tail = 0;
Peter Hurley17bd7902013-06-15 10:04:24 -0400328 ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0;
Peter Hurley70aca712015-01-16 15:05:37 -0500329 ldata->commit_head = 0;
Peter Hurley1075a6e2013-12-09 18:06:07 -0500330 ldata->echo_mark = 0;
Peter Hurley40d5e092013-06-15 10:21:17 -0400331 ldata->line_start = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000332
Peter Hurleya73d3d62013-06-15 09:14:25 -0400333 ldata->erasing = 0;
Jiri Slaby3fe780b2012-10-18 22:26:40 +0200334 bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
Peter Hurley4d0ed182013-12-10 17:12:02 -0500335 ldata->push = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336}
337
Peter Hurleya30737a2013-03-11 16:44:22 -0400338static void n_tty_packet_mode_flush(struct tty_struct *tty)
339{
340 unsigned long flags;
341
Peter Hurleya30737a2013-03-11 16:44:22 -0400342 if (tty->link->packet) {
Peter Hurley54e8e5f2014-10-16 15:33:26 -0400343 spin_lock_irqsave(&tty->ctrl_lock, flags);
Peter Hurleya30737a2013-03-11 16:44:22 -0400344 tty->ctrl_status |= TIOCPKT_FLUSHREAD;
Peter Hurley54e8e5f2014-10-16 15:33:26 -0400345 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
Kosuke Tatsukawae81107d2015-10-02 08:27:05 +0000346 wake_up_interruptible(&tty->link->read_wait);
Peter Hurleya30737a2013-03-11 16:44:22 -0400347 }
Peter Hurleya30737a2013-03-11 16:44:22 -0400348}
349
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350/**
351 * n_tty_flush_buffer - clean input queue
352 * @tty: terminal device
353 *
Peter Hurley25518c62013-03-11 16:44:31 -0400354 * Flush the input buffer. Called when the tty layer wants the
355 * buffer flushed (eg at hangup) or when the N_TTY line discipline
356 * internally has to clean the pending queue (for example some signals).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400358 * Holds termios_rwsem to exclude producer/consumer while
359 * buffer indices are reset.
360 *
361 * Locking: ctrl_lock, exclusive termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 */
Alan Cox4edf1822008-02-08 04:18:44 -0800363
364static void n_tty_flush_buffer(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365{
Peter Hurley6d76bd22013-06-15 09:14:26 -0400366 down_write(&tty->termios_rwsem);
Peter Hurleyb66f4fa2013-03-11 16:44:32 -0400367 reset_buffer_flags(tty->disc_data);
Peter Hurley2c5dc462015-01-16 15:05:34 -0500368 n_tty_kick_worker(tty);
Alan Cox4edf1822008-02-08 04:18:44 -0800369
Peter Hurleya30737a2013-03-11 16:44:22 -0400370 if (tty->link)
371 n_tty_packet_mode_flush(tty);
Peter Hurley6d76bd22013-06-15 09:14:26 -0400372 up_write(&tty->termios_rwsem);
373}
374
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375/**
376 * n_tty_chars_in_buffer - report available bytes
377 * @tty: tty device
378 *
379 * Report the number of characters buffered to be delivered to user
Alan Cox4edf1822008-02-08 04:18:44 -0800380 * at this instant in time.
Alan Cox17b82062008-10-13 10:45:06 +0100381 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400382 * Locking: exclusive termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 */
Alan Cox4edf1822008-02-08 04:18:44 -0800384
Peter Hurleya19d0c62013-06-15 09:14:18 -0400385static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
386{
Peter Hurley6d76bd22013-06-15 09:14:26 -0400387 ssize_t n;
388
Peter Hurley47534082013-06-15 09:14:19 -0400389 WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__);
Peter Hurley6d76bd22013-06-15 09:14:26 -0400390
391 down_write(&tty->termios_rwsem);
392 n = chars_in_buffer(tty);
393 up_write(&tty->termios_rwsem);
394 return n;
Peter Hurleya19d0c62013-06-15 09:14:18 -0400395}
396
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397/**
398 * is_utf8_continuation - utf8 multibyte check
399 * @c: byte to check
400 *
401 * Returns true if the utf8 character 'c' is a multibyte continuation
402 * character. We use this to correctly compute the on screen size
403 * of the character when printing
404 */
Alan Cox4edf1822008-02-08 04:18:44 -0800405
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406static inline int is_utf8_continuation(unsigned char c)
407{
408 return (c & 0xc0) == 0x80;
409}
410
411/**
412 * is_continuation - multibyte check
413 * @c: byte to check
414 *
415 * Returns true if the utf8 character 'c' is a multibyte continuation
416 * character and the terminal is in unicode mode.
417 */
Alan Cox4edf1822008-02-08 04:18:44 -0800418
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419static inline int is_continuation(unsigned char c, struct tty_struct *tty)
420{
421 return I_IUTF8(tty) && is_utf8_continuation(c);
422}
423
424/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000425 * do_output_char - output one character
426 * @c: character (or partial unicode symbol)
427 * @tty: terminal device
428 * @space: space available in tty driver write buffer
429 *
430 * This is a helper function that handles one output character
431 * (including special characters like TAB, CR, LF, etc.),
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600432 * doing OPOST processing and putting the results in the
433 * tty driver's write buffer.
Joe Petersona88a69c2009-01-02 13:40:53 +0000434 *
435 * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY
436 * and NLDLY. They simply aren't relevant in the world today.
437 * If you ever need them, add them here.
438 *
439 * Returns the number of bytes of buffer space used or -1 if
440 * no space left.
441 *
442 * Locking: should be called under the output_lock to protect
443 * the column state and space left in the buffer
444 */
445
446static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
447{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200448 struct n_tty_data *ldata = tty->disc_data;
Joe Petersona88a69c2009-01-02 13:40:53 +0000449 int spaces;
450
451 if (!space)
452 return -1;
Alan Cox300a6202009-01-02 13:41:04 +0000453
Joe Petersona88a69c2009-01-02 13:40:53 +0000454 switch (c) {
455 case '\n':
456 if (O_ONLRET(tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200457 ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000458 if (O_ONLCR(tty)) {
459 if (space < 2)
460 return -1;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200461 ldata->canon_column = ldata->column = 0;
Linus Torvalds37f81fa2009-09-05 12:46:07 -0700462 tty->ops->write(tty, "\r\n", 2);
Joe Petersona88a69c2009-01-02 13:40:53 +0000463 return 2;
464 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200465 ldata->canon_column = ldata->column;
Joe Petersona88a69c2009-01-02 13:40:53 +0000466 break;
467 case '\r':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200468 if (O_ONOCR(tty) && ldata->column == 0)
Joe Petersona88a69c2009-01-02 13:40:53 +0000469 return 0;
470 if (O_OCRNL(tty)) {
471 c = '\n';
472 if (O_ONLRET(tty))
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200473 ldata->canon_column = ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000474 break;
475 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200476 ldata->canon_column = ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000477 break;
478 case '\t':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200479 spaces = 8 - (ldata->column & 7);
Joe Petersona88a69c2009-01-02 13:40:53 +0000480 if (O_TABDLY(tty) == XTABS) {
481 if (space < spaces)
482 return -1;
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200483 ldata->column += spaces;
Joe Petersona88a69c2009-01-02 13:40:53 +0000484 tty->ops->write(tty, " ", spaces);
485 return spaces;
486 }
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200487 ldata->column += spaces;
Joe Petersona88a69c2009-01-02 13:40:53 +0000488 break;
489 case '\b':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200490 if (ldata->column > 0)
491 ldata->column--;
Joe Petersona88a69c2009-01-02 13:40:53 +0000492 break;
493 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000494 if (!iscntrl(c)) {
495 if (O_OLCUC(tty))
496 c = toupper(c);
497 if (!is_continuation(c, tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200498 ldata->column++;
Joe Petersona59c0d62009-01-02 13:43:25 +0000499 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000500 break;
501 }
502
503 tty_put_char(tty, c);
504 return 1;
505}
506
507/**
508 * process_output - output post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 * @c: character (or partial unicode symbol)
510 * @tty: terminal device
511 *
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600512 * Output one character with OPOST processing.
513 * Returns -1 when the output device is full and the character
514 * must be retried.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000516 * Locking: output_lock to protect column state and space left
517 * (also, this is called from n_tty_write under the
518 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 */
Alan Cox4edf1822008-02-08 04:18:44 -0800520
Joe Petersona88a69c2009-01-02 13:40:53 +0000521static int process_output(unsigned char c, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522{
Jiri Slabybddc7152012-10-18 22:26:42 +0200523 struct n_tty_data *ldata = tty->disc_data;
Joe Petersona88a69c2009-01-02 13:40:53 +0000524 int space, retval;
525
Jiri Slabybddc7152012-10-18 22:26:42 +0200526 mutex_lock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
Alan Coxf34d7a52008-04-30 00:54:13 -0700528 space = tty_write_room(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +0000529 retval = do_output_char(c, tty, space);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530
Jiri Slabybddc7152012-10-18 22:26:42 +0200531 mutex_unlock(&ldata->output_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000532 if (retval < 0)
533 return -1;
534 else
535 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536}
537
538/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000539 * process_output_block - block post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 * @tty: terminal device
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600541 * @buf: character buffer
542 * @nr: number of bytes to output
543 *
544 * Output a block of characters with OPOST processing.
545 * Returns the number of characters output.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 *
547 * This path is used to speed up block console writes, among other
548 * things when processing blocks of output data. It handles only
549 * the simple cases normally found and helps to generate blocks of
550 * symbols for the console driver and thus improve performance.
551 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000552 * Locking: output_lock to protect column state and space left
553 * (also, this is called from n_tty_write under the
554 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 */
Alan Cox4edf1822008-02-08 04:18:44 -0800556
Joe Petersona88a69c2009-01-02 13:40:53 +0000557static ssize_t process_output_block(struct tty_struct *tty,
558 const unsigned char *buf, unsigned int nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200560 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 int space;
Thorsten Wißmannbbd20752011-12-08 17:47:33 +0100562 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 const unsigned char *cp;
564
Jiri Slabybddc7152012-10-18 22:26:42 +0200565 mutex_lock(&ldata->output_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000566
Alan Coxf34d7a52008-04-30 00:54:13 -0700567 space = tty_write_room(tty);
Alan Cox300a6202009-01-02 13:41:04 +0000568 if (!space) {
Jiri Slabybddc7152012-10-18 22:26:42 +0200569 mutex_unlock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 return 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000571 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 if (nr > space)
573 nr = space;
574
575 for (i = 0, cp = buf; i < nr; i++, cp++) {
Joe Petersona59c0d62009-01-02 13:43:25 +0000576 unsigned char c = *cp;
577
578 switch (c) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 case '\n':
580 if (O_ONLRET(tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200581 ldata->column = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 if (O_ONLCR(tty))
583 goto break_out;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200584 ldata->canon_column = ldata->column;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 break;
586 case '\r':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200587 if (O_ONOCR(tty) && ldata->column == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 goto break_out;
589 if (O_OCRNL(tty))
590 goto break_out;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200591 ldata->canon_column = ldata->column = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 break;
593 case '\t':
594 goto break_out;
595 case '\b':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200596 if (ldata->column > 0)
597 ldata->column--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 break;
599 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000600 if (!iscntrl(c)) {
601 if (O_OLCUC(tty))
602 goto break_out;
603 if (!is_continuation(c, tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200604 ldata->column++;
Joe Petersona59c0d62009-01-02 13:43:25 +0000605 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 break;
607 }
608 }
609break_out:
Alan Coxf34d7a52008-04-30 00:54:13 -0700610 i = tty->ops->write(tty, buf, i);
Joe Petersona88a69c2009-01-02 13:40:53 +0000611
Jiri Slabybddc7152012-10-18 22:26:42 +0200612 mutex_unlock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 return i;
614}
615
Joe Petersona88a69c2009-01-02 13:40:53 +0000616/**
617 * process_echoes - write pending echo characters
618 * @tty: terminal device
619 *
620 * Write previously buffered echo (and other ldisc-generated)
621 * characters to the tty.
622 *
623 * Characters generated by the ldisc (including echoes) need to
624 * be buffered because the driver's write buffer can fill during
625 * heavy program output. Echoing straight to the driver will
626 * often fail under these conditions, causing lost characters and
627 * resulting mismatches of ldisc state information.
628 *
629 * Since the ldisc state must represent the characters actually sent
630 * to the driver at the time of the write, operations like certain
631 * changes in column state are also saved in the buffer and executed
632 * here.
633 *
634 * A circular fifo buffer is used so that the most recent characters
635 * are prioritized. Also, when control characters are echoed with a
636 * prefixed "^", the pair is treated atomically and thus not separated.
637 *
Peter Hurley019ebdf2013-06-15 10:04:25 -0400638 * Locking: callers must hold output_lock
Joe Petersona88a69c2009-01-02 13:40:53 +0000639 */
640
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400641static size_t __process_echoes(struct tty_struct *tty)
Joe Petersona88a69c2009-01-02 13:40:53 +0000642{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200643 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400644 int space, old_space;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400645 size_t tail;
Joe Petersona88a69c2009-01-02 13:40:53 +0000646 unsigned char c;
Joe Petersona88a69c2009-01-02 13:40:53 +0000647
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400648 old_space = space = tty_write_room(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +0000649
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400650 tail = ldata->echo_tail;
Peter Hurley29c7c5c2013-06-15 10:04:28 -0400651 while (ldata->echo_commit != tail) {
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400652 c = echo_buf(ldata, tail);
Joe Petersona88a69c2009-01-02 13:40:53 +0000653 if (c == ECHO_OP_START) {
654 unsigned char op;
Joe Petersona88a69c2009-01-02 13:40:53 +0000655 int no_space_left = 0;
656
657 /*
658 * If the buffer byte is the start of a multi-byte
659 * operation, get the next byte, which is either the
660 * op code or a control character value.
661 */
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400662 op = echo_buf(ldata, tail + 1);
Alan Cox300a6202009-01-02 13:41:04 +0000663
Joe Petersona88a69c2009-01-02 13:40:53 +0000664 switch (op) {
665 unsigned int num_chars, num_bs;
666
667 case ECHO_OP_ERASE_TAB:
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400668 num_chars = echo_buf(ldata, tail + 2);
Joe Petersona88a69c2009-01-02 13:40:53 +0000669
670 /*
671 * Determine how many columns to go back
672 * in order to erase the tab.
673 * This depends on the number of columns
674 * used by other characters within the tab
675 * area. If this (modulo 8) count is from
676 * the start of input rather than from a
677 * previous tab, we offset by canon column.
678 * Otherwise, tab spacing is normal.
679 */
680 if (!(num_chars & 0x80))
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200681 num_chars += ldata->canon_column;
Joe Petersona88a69c2009-01-02 13:40:53 +0000682 num_bs = 8 - (num_chars & 7);
683
684 if (num_bs > space) {
685 no_space_left = 1;
686 break;
687 }
688 space -= num_bs;
689 while (num_bs--) {
690 tty_put_char(tty, '\b');
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200691 if (ldata->column > 0)
692 ldata->column--;
Joe Petersona88a69c2009-01-02 13:40:53 +0000693 }
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400694 tail += 3;
Joe Petersona88a69c2009-01-02 13:40:53 +0000695 break;
696
697 case ECHO_OP_SET_CANON_COL:
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200698 ldata->canon_column = ldata->column;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400699 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000700 break;
701
702 case ECHO_OP_MOVE_BACK_COL:
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200703 if (ldata->column > 0)
704 ldata->column--;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400705 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000706 break;
707
708 case ECHO_OP_START:
709 /* This is an escaped echo op start code */
710 if (!space) {
711 no_space_left = 1;
712 break;
713 }
714 tty_put_char(tty, ECHO_OP_START);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200715 ldata->column++;
Joe Petersona88a69c2009-01-02 13:40:53 +0000716 space--;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400717 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000718 break;
719
720 default:
Joe Petersona88a69c2009-01-02 13:40:53 +0000721 /*
Joe Peterson62b26352009-09-09 15:03:47 -0600722 * If the op is not a special byte code,
723 * it is a ctrl char tagged to be echoed
724 * as "^X" (where X is the letter
725 * representing the control char).
726 * Note that we must ensure there is
727 * enough space for the whole ctrl pair.
728 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000729 */
Joe Peterson62b26352009-09-09 15:03:47 -0600730 if (space < 2) {
731 no_space_left = 1;
732 break;
733 }
734 tty_put_char(tty, '^');
735 tty_put_char(tty, op ^ 0100);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200736 ldata->column += 2;
Joe Peterson62b26352009-09-09 15:03:47 -0600737 space -= 2;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400738 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000739 }
740
741 if (no_space_left)
742 break;
743 } else {
Peter Hurley582f5592013-05-17 12:49:48 -0400744 if (O_OPOST(tty)) {
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600745 int retval = do_output_char(c, tty, space);
746 if (retval < 0)
747 break;
748 space -= retval;
749 } else {
750 if (!space)
751 break;
752 tty_put_char(tty, c);
753 space -= 1;
754 }
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400755 tail += 1;
Joe Petersona88a69c2009-01-02 13:40:53 +0000756 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000757 }
758
Peter Hurleycbfd0342013-06-15 10:04:26 -0400759 /* If the echo buffer is nearly full (so that the possibility exists
760 * of echo overrun before the next commit), then discard enough
761 * data at the tail to prevent a subsequent overrun */
762 while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) {
Roel Kluinc476f652013-10-11 22:08:49 +0200763 if (echo_buf(ldata, tail) == ECHO_OP_START) {
Peter Hurley6f222532013-11-08 09:42:18 -0500764 if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB)
Peter Hurleycbfd0342013-06-15 10:04:26 -0400765 tail += 3;
766 else
767 tail += 2;
768 } else
769 tail++;
770 }
771
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400772 ldata->echo_tail = tail;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400773 return old_space - space;
Joe Petersona88a69c2009-01-02 13:40:53 +0000774}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775
Peter Hurley17bd7902013-06-15 10:04:24 -0400776static void commit_echoes(struct tty_struct *tty)
777{
778 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400779 size_t nr, old, echoed;
Peter Hurleycbfd0342013-06-15 10:04:26 -0400780 size_t head;
781
782 head = ldata->echo_head;
Peter Hurley1075a6e2013-12-09 18:06:07 -0500783 ldata->echo_mark = head;
Peter Hurleycbfd0342013-06-15 10:04:26 -0400784 old = ldata->echo_commit - ldata->echo_tail;
785
786 /* Process committed echoes if the accumulated # of bytes
787 * is over the threshold (and try again each time another
788 * block is accumulated) */
789 nr = head - ldata->echo_tail;
790 if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK))
791 return;
Peter Hurley17bd7902013-06-15 10:04:24 -0400792
Peter Hurley019ebdf2013-06-15 10:04:25 -0400793 mutex_lock(&ldata->output_lock);
Peter Hurleycbfd0342013-06-15 10:04:26 -0400794 ldata->echo_commit = head;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400795 echoed = __process_echoes(tty);
Peter Hurley019ebdf2013-06-15 10:04:25 -0400796 mutex_unlock(&ldata->output_lock);
797
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400798 if (echoed && tty->ops->flush_chars)
Peter Hurley019ebdf2013-06-15 10:04:25 -0400799 tty->ops->flush_chars(tty);
800}
801
802static void process_echoes(struct tty_struct *tty)
803{
804 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400805 size_t echoed;
Peter Hurley019ebdf2013-06-15 10:04:25 -0400806
Peter Hurleye2613be2014-02-11 16:34:55 -0500807 if (ldata->echo_mark == ldata->echo_tail)
Peter Hurley019ebdf2013-06-15 10:04:25 -0400808 return;
809
810 mutex_lock(&ldata->output_lock);
Peter Hurley1075a6e2013-12-09 18:06:07 -0500811 ldata->echo_commit = ldata->echo_mark;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400812 echoed = __process_echoes(tty);
Peter Hurley019ebdf2013-06-15 10:04:25 -0400813 mutex_unlock(&ldata->output_lock);
814
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400815 if (echoed && tty->ops->flush_chars)
Peter Hurley019ebdf2013-06-15 10:04:25 -0400816 tty->ops->flush_chars(tty);
Peter Hurley17bd7902013-06-15 10:04:24 -0400817}
818
Peter Hurley1075a6e2013-12-09 18:06:07 -0500819/* NB: echo_mark and echo_head should be equivalent here */
Peter Hurleycbfd0342013-06-15 10:04:26 -0400820static void flush_echoes(struct tty_struct *tty)
821{
822 struct n_tty_data *ldata = tty->disc_data;
823
Peter Hurley39434ab2013-11-29 12:56:10 -0500824 if ((!L_ECHO(tty) && !L_ECHONL(tty)) ||
825 ldata->echo_commit == ldata->echo_head)
Peter Hurleycbfd0342013-06-15 10:04:26 -0400826 return;
827
828 mutex_lock(&ldata->output_lock);
829 ldata->echo_commit = ldata->echo_head;
830 __process_echoes(tty);
831 mutex_unlock(&ldata->output_lock);
832}
833
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000835 * add_echo_byte - add a byte to the echo buffer
836 * @c: unicode byte to echo
Jiri Slaby57c94122012-10-18 22:26:43 +0200837 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000838 *
839 * Add a character or operation byte to the echo buffer.
Joe Petersona88a69c2009-01-02 13:40:53 +0000840 */
841
Peter Hurleycbfd0342013-06-15 10:04:26 -0400842static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000843{
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400844 *echo_buf_addr(ldata, ldata->echo_head++) = c;
Joe Petersona88a69c2009-01-02 13:40:53 +0000845}
846
847/**
848 * echo_move_back_col - add operation to move back a column
Jiri Slaby57c94122012-10-18 22:26:43 +0200849 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000850 *
851 * Add an operation to the echo buffer to move back one column.
Joe Petersona88a69c2009-01-02 13:40:53 +0000852 */
853
Jiri Slaby57c94122012-10-18 22:26:43 +0200854static void echo_move_back_col(struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000855{
Jiri Slaby57c94122012-10-18 22:26:43 +0200856 add_echo_byte(ECHO_OP_START, ldata);
857 add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000858}
859
860/**
861 * echo_set_canon_col - add operation to set the canon column
Jiri Slaby57c94122012-10-18 22:26:43 +0200862 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000863 *
864 * Add an operation to the echo buffer to set the canon column
865 * to the current column.
Joe Petersona88a69c2009-01-02 13:40:53 +0000866 */
867
Jiri Slaby57c94122012-10-18 22:26:43 +0200868static void echo_set_canon_col(struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000869{
Jiri Slaby57c94122012-10-18 22:26:43 +0200870 add_echo_byte(ECHO_OP_START, ldata);
871 add_echo_byte(ECHO_OP_SET_CANON_COL, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000872}
873
874/**
875 * echo_erase_tab - add operation to erase a tab
876 * @num_chars: number of character columns already used
877 * @after_tab: true if num_chars starts after a previous tab
Jiri Slaby57c94122012-10-18 22:26:43 +0200878 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000879 *
880 * Add an operation to the echo buffer to erase a tab.
881 *
882 * Called by the eraser function, which knows how many character
883 * columns have been used since either a previous tab or the start
884 * of input. This information will be used later, along with
885 * canon column (if applicable), to go back the correct number
886 * of columns.
Joe Petersona88a69c2009-01-02 13:40:53 +0000887 */
888
889static void echo_erase_tab(unsigned int num_chars, int after_tab,
Jiri Slaby57c94122012-10-18 22:26:43 +0200890 struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000891{
Jiri Slaby57c94122012-10-18 22:26:43 +0200892 add_echo_byte(ECHO_OP_START, ldata);
893 add_echo_byte(ECHO_OP_ERASE_TAB, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000894
895 /* We only need to know this modulo 8 (tab spacing) */
896 num_chars &= 7;
897
898 /* Set the high bit as a flag if num_chars is after a previous tab */
899 if (after_tab)
900 num_chars |= 0x80;
Alan Cox300a6202009-01-02 13:41:04 +0000901
Jiri Slaby57c94122012-10-18 22:26:43 +0200902 add_echo_byte(num_chars, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000903}
904
905/**
906 * echo_char_raw - echo a character raw
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 * @c: unicode byte to echo
908 * @tty: terminal device
909 *
Alan Cox4edf1822008-02-08 04:18:44 -0800910 * Echo user input back onto the screen. This must be called only when
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 * L_ECHO(tty) is true. Called from the driver receive_buf path.
Alan Cox17b82062008-10-13 10:45:06 +0100912 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000913 * This variant does not treat control characters specially.
Joe Petersona88a69c2009-01-02 13:40:53 +0000914 */
915
Jiri Slaby57c94122012-10-18 22:26:43 +0200916static void echo_char_raw(unsigned char c, struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000917{
Joe Petersona88a69c2009-01-02 13:40:53 +0000918 if (c == ECHO_OP_START) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200919 add_echo_byte(ECHO_OP_START, ldata);
920 add_echo_byte(ECHO_OP_START, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000921 } else {
Jiri Slaby57c94122012-10-18 22:26:43 +0200922 add_echo_byte(c, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000923 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000924}
925
926/**
927 * echo_char - echo a character
928 * @c: unicode byte to echo
929 * @tty: terminal device
930 *
931 * Echo user input back onto the screen. This must be called only when
932 * L_ECHO(tty) is true. Called from the driver receive_buf path.
933 *
Joe Peterson62b26352009-09-09 15:03:47 -0600934 * This variant tags control characters to be echoed as "^X"
935 * (where X is the letter representing the control char).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700936 */
937
938static void echo_char(unsigned char c, struct tty_struct *tty)
939{
Jiri Slabybddc7152012-10-18 22:26:42 +0200940 struct n_tty_data *ldata = tty->disc_data;
941
Joe Petersona88a69c2009-01-02 13:40:53 +0000942 if (c == ECHO_OP_START) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200943 add_echo_byte(ECHO_OP_START, ldata);
944 add_echo_byte(ECHO_OP_START, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000945 } else {
Joe Peterson62b26352009-09-09 15:03:47 -0600946 if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t')
Jiri Slaby57c94122012-10-18 22:26:43 +0200947 add_echo_byte(ECHO_OP_START, ldata);
948 add_echo_byte(c, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000949 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950}
951
Alan Cox17b82062008-10-13 10:45:06 +0100952/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000953 * finish_erasing - complete erase
Jiri Slaby57c94122012-10-18 22:26:43 +0200954 * @ldata: n_tty data
Alan Cox17b82062008-10-13 10:45:06 +0100955 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000956
Jiri Slaby57c94122012-10-18 22:26:43 +0200957static inline void finish_erasing(struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200959 if (ldata->erasing) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200960 echo_char_raw('/', ldata);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200961 ldata->erasing = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 }
963}
964
965/**
966 * eraser - handle erase function
967 * @c: character input
968 * @tty: terminal device
969 *
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200970 * Perform erase and necessary output when an erase character is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971 * present in the stream from the driver layer. Handles the complexities
972 * of UTF-8 multibyte symbols.
Alan Cox17b82062008-10-13 10:45:06 +0100973 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400974 * n_tty_receive_buf()/producer path:
975 * caller holds non-exclusive termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 */
Alan Cox4edf1822008-02-08 04:18:44 -0800977
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978static void eraser(unsigned char c, struct tty_struct *tty)
979{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200980 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981 enum { ERASE, WERASE, KILL } kill_type;
Peter Hurleybc5a5e32013-06-15 09:14:21 -0400982 size_t head;
983 size_t cnt;
984 int seen_alnums;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200986 if (ldata->read_head == ldata->canon_head) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +0000987 /* process_output('\a', tty); */ /* what do you think? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988 return;
989 }
990 if (c == ERASE_CHAR(tty))
991 kill_type = ERASE;
992 else if (c == WERASE_CHAR(tty))
993 kill_type = WERASE;
994 else {
995 if (!L_ECHO(tty)) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200996 ldata->read_head = ldata->canon_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 return;
998 }
999 if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001000 ldata->read_head = ldata->canon_head;
Jiri Slaby57c94122012-10-18 22:26:43 +02001001 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002 echo_char(KILL_CHAR(tty), tty);
1003 /* Add a newline if ECHOK is on and ECHOKE is off. */
1004 if (L_ECHOK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001005 echo_char_raw('\n', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006 return;
1007 }
1008 kill_type = KILL;
1009 }
1010
1011 seen_alnums = 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001012 while (ldata->read_head != ldata->canon_head) {
1013 head = ldata->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014
1015 /* erase a single possibly multibyte character */
1016 do {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001017 head--;
1018 c = read_buf(ldata, head);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001019 } while (is_continuation(c, tty) && head != ldata->canon_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020
1021 /* do not partially erase */
1022 if (is_continuation(c, tty))
1023 break;
1024
1025 if (kill_type == WERASE) {
1026 /* Equivalent to BSD's ALTWERASE. */
1027 if (isalnum(c) || c == '_')
1028 seen_alnums++;
1029 else if (seen_alnums)
1030 break;
1031 }
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001032 cnt = ldata->read_head - head;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001033 ldata->read_head = head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034 if (L_ECHO(tty)) {
1035 if (L_ECHOPRT(tty)) {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001036 if (!ldata->erasing) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001037 echo_char_raw('\\', ldata);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001038 ldata->erasing = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039 }
1040 /* if cnt > 1, output a multi-byte character */
1041 echo_char(c, tty);
1042 while (--cnt > 0) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001043 head++;
1044 echo_char_raw(read_buf(ldata, head), ldata);
Jiri Slaby57c94122012-10-18 22:26:43 +02001045 echo_move_back_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 }
1047 } else if (kill_type == ERASE && !L_ECHOE(tty)) {
1048 echo_char(ERASE_CHAR(tty), tty);
1049 } else if (c == '\t') {
Joe Petersona88a69c2009-01-02 13:40:53 +00001050 unsigned int num_chars = 0;
1051 int after_tab = 0;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001052 size_t tail = ldata->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001053
Joe Petersona88a69c2009-01-02 13:40:53 +00001054 /*
1055 * Count the columns used for characters
1056 * since the start of input or after a
1057 * previous tab.
1058 * This info is used to go back the correct
1059 * number of columns.
1060 */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001061 while (tail != ldata->canon_head) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001062 tail--;
1063 c = read_buf(ldata, tail);
Joe Petersona88a69c2009-01-02 13:40:53 +00001064 if (c == '\t') {
1065 after_tab = 1;
1066 break;
Alan Cox300a6202009-01-02 13:41:04 +00001067 } else if (iscntrl(c)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068 if (L_ECHOCTL(tty))
Joe Petersona88a69c2009-01-02 13:40:53 +00001069 num_chars += 2;
1070 } else if (!is_continuation(c, tty)) {
1071 num_chars++;
1072 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073 }
Jiri Slaby57c94122012-10-18 22:26:43 +02001074 echo_erase_tab(num_chars, after_tab, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001075 } else {
1076 if (iscntrl(c) && L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001077 echo_char_raw('\b', ldata);
1078 echo_char_raw(' ', ldata);
1079 echo_char_raw('\b', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 }
1081 if (!iscntrl(c) || L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001082 echo_char_raw('\b', ldata);
1083 echo_char_raw(' ', ldata);
1084 echo_char_raw('\b', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085 }
1086 }
1087 }
1088 if (kill_type == ERASE)
1089 break;
1090 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001091 if (ldata->read_head == ldata->canon_head && L_ECHO(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001092 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093}
1094
1095/**
1096 * isig - handle the ISIG optio
1097 * @sig: signal
1098 * @tty: terminal
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099 *
Peter Hurley8c985d12013-03-06 08:38:19 -05001100 * Called when a signal is being sent due to terminal input.
1101 * Called from the driver receive_buf path so serialized.
Alan Cox17b82062008-10-13 10:45:06 +01001102 *
Peter Hurleyd2b6f442015-01-17 15:42:06 -05001103 * Performs input and output flush if !NOFLSH. In this context, the echo
1104 * buffer is 'output'. The signal is processed first to alert any current
1105 * readers or writers to discontinue and exit their i/o loops.
1106 *
Peter Hurley8c985d12013-03-06 08:38:19 -05001107 * Locking: ctrl_lock
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 */
Alan Cox4edf1822008-02-08 04:18:44 -08001109
Peter Hurley3b19e032015-06-27 09:21:32 -04001110static void __isig(int sig, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001111{
Peter Hurley8c985d12013-03-06 08:38:19 -05001112 struct pid *tty_pgrp = tty_get_pgrp(tty);
1113 if (tty_pgrp) {
1114 kill_pgrp(tty_pgrp, sig, 1);
1115 put_pid(tty_pgrp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 }
Peter Hurley3b19e032015-06-27 09:21:32 -04001117}
Peter Hurleyd2b6f442015-01-17 15:42:06 -05001118
Peter Hurley3b19e032015-06-27 09:21:32 -04001119static void isig(int sig, struct tty_struct *tty)
1120{
1121 struct n_tty_data *ldata = tty->disc_data;
1122
1123 if (L_NOFLSH(tty)) {
1124 /* signal only */
1125 __isig(sig, tty);
1126
1127 } else { /* signal and flush */
Peter Hurleyd2b6f442015-01-17 15:42:06 -05001128 up_read(&tty->termios_rwsem);
1129 down_write(&tty->termios_rwsem);
1130
Peter Hurley3b19e032015-06-27 09:21:32 -04001131 __isig(sig, tty);
1132
Peter Hurleyd2b6f442015-01-17 15:42:06 -05001133 /* clear echo buffer */
1134 mutex_lock(&ldata->output_lock);
1135 ldata->echo_head = ldata->echo_tail = 0;
1136 ldata->echo_mark = ldata->echo_commit = 0;
1137 mutex_unlock(&ldata->output_lock);
1138
1139 /* clear output buffer */
1140 tty_driver_flush_buffer(tty);
1141
1142 /* clear input buffer */
1143 reset_buffer_flags(tty->disc_data);
1144
1145 /* notify pty master of flush */
1146 if (tty->link)
1147 n_tty_packet_mode_flush(tty);
1148
1149 up_write(&tty->termios_rwsem);
1150 down_read(&tty->termios_rwsem);
1151 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152}
1153
1154/**
1155 * n_tty_receive_break - handle break
1156 * @tty: terminal
1157 *
1158 * An RS232 break event has been hit in the incoming bitstream. This
1159 * can cause a variety of events depending upon the termios settings.
1160 *
Peter Hurley6d76bd22013-06-15 09:14:26 -04001161 * n_tty_receive_buf()/producer path:
1162 * caller holds non-exclusive termios_rwsem
Peter Hurley6d76bd22013-06-15 09:14:26 -04001163 *
1164 * Note: may get exclusive termios_rwsem if flushing input buffer
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165 */
Alan Cox4edf1822008-02-08 04:18:44 -08001166
Peter Hurley4b293492013-07-24 08:29:55 -04001167static void n_tty_receive_break(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168{
Jiri Slaby57c94122012-10-18 22:26:43 +02001169 struct n_tty_data *ldata = tty->disc_data;
1170
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 if (I_IGNBRK(tty))
1172 return;
1173 if (I_BRKINT(tty)) {
Peter Hurley8c985d12013-03-06 08:38:19 -05001174 isig(SIGINT, tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175 return;
1176 }
1177 if (I_PARMRK(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001178 put_tty_queue('\377', ldata);
1179 put_tty_queue('\0', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180 }
Jiri Slaby57c94122012-10-18 22:26:43 +02001181 put_tty_queue('\0', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182}
1183
1184/**
1185 * n_tty_receive_overrun - handle overrun reporting
1186 * @tty: terminal
1187 *
1188 * Data arrived faster than we could process it. While the tty
1189 * driver has flagged this the bits that were missed are gone
1190 * forever.
1191 *
1192 * Called from the receive_buf path so single threaded. Does not
1193 * need locking as num_overrun and overrun_time are function
1194 * private.
1195 */
Alan Cox4edf1822008-02-08 04:18:44 -08001196
Peter Hurley4b293492013-07-24 08:29:55 -04001197static void n_tty_receive_overrun(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001199 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001201 ldata->num_overrun++;
1202 if (time_after(jiffies, ldata->overrun_time + HZ) ||
1203 time_after(ldata->overrun_time, jiffies)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 printk(KERN_WARNING "%s: %d input overrun(s)\n",
Rasmus Villemoes429b4742015-03-31 15:55:59 +02001205 tty_name(tty),
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001206 ldata->num_overrun);
1207 ldata->overrun_time = jiffies;
1208 ldata->num_overrun = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 }
1210}
1211
1212/**
1213 * n_tty_receive_parity_error - error notifier
1214 * @tty: terminal device
1215 * @c: character
1216 *
1217 * Process a parity error and queue the right data to indicate
Peter Hurley6d76bd22013-06-15 09:14:26 -04001218 * the error case if necessary.
1219 *
1220 * n_tty_receive_buf()/producer path:
1221 * caller holds non-exclusive termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 */
Peter Hurley4b293492013-07-24 08:29:55 -04001223static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224{
Jiri Slaby57c94122012-10-18 22:26:43 +02001225 struct n_tty_data *ldata = tty->disc_data;
1226
Peter Hurley66528f92014-06-16 08:10:42 -04001227 if (I_INPCK(tty)) {
1228 if (I_IGNPAR(tty))
1229 return;
1230 if (I_PARMRK(tty)) {
1231 put_tty_queue('\377', ldata);
1232 put_tty_queue('\0', ldata);
1233 put_tty_queue(c, ldata);
1234 } else
1235 put_tty_queue('\0', ldata);
1236 } else
Jiri Slaby57c94122012-10-18 22:26:43 +02001237 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238}
1239
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001240static void
1241n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c)
1242{
Peter Hurleyd2b6f442015-01-17 15:42:06 -05001243 isig(signal, tty);
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001244 if (I_IXON(tty))
1245 start_tty(tty);
1246 if (L_ECHO(tty)) {
1247 echo_char(c, tty);
1248 commit_echoes(tty);
Peter Hurleye2613be2014-02-11 16:34:55 -05001249 } else
1250 process_echoes(tty);
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001251 return;
1252}
1253
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254/**
1255 * n_tty_receive_char - perform processing
1256 * @tty: terminal device
1257 * @c: character
1258 *
1259 * Process an individual character of input received from the driver.
Alan Cox4edf1822008-02-08 04:18:44 -08001260 * This is serialized with respect to itself by the rules for the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261 * driver above.
Peter Hurley6d76bd22013-06-15 09:14:26 -04001262 *
1263 * n_tty_receive_buf()/producer path:
1264 * caller holds non-exclusive termios_rwsem
1265 * publishes canon_head if canonical mode is active
Peter Hurleye60d27c2013-07-24 08:29:56 -04001266 *
1267 * Returns 1 if LNEXT was received, else returns 0
Linus Torvalds1da177e2005-04-16 15:20:36 -07001268 */
1269
Peter Hurleye60d27c2013-07-24 08:29:56 -04001270static int
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001271n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001272{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001273 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 if (I_IXON(tty)) {
1276 if (c == START_CHAR(tty)) {
1277 start_tty(tty);
Peter Hurleye2613be2014-02-11 16:34:55 -05001278 process_echoes(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001279 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280 }
1281 if (c == STOP_CHAR(tty)) {
1282 stop_tty(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001283 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284 }
1285 }
Joe Peterson575537b32008-04-30 00:53:30 -07001286
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287 if (L_ISIG(tty)) {
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001288 if (c == INTR_CHAR(tty)) {
1289 n_tty_receive_signal_char(tty, SIGINT, c);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001290 return 0;
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001291 } else if (c == QUIT_CHAR(tty)) {
1292 n_tty_receive_signal_char(tty, SIGQUIT, c);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001293 return 0;
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001294 } else if (c == SUSP_CHAR(tty)) {
1295 n_tty_receive_signal_char(tty, SIGTSTP, c);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001296 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297 }
1298 }
Joe Peterson575537b32008-04-30 00:53:30 -07001299
Peter Hurley855df3c2013-07-24 08:29:50 -04001300 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
1301 start_tty(tty);
1302 process_echoes(tty);
1303 }
1304
Joe Peterson575537b32008-04-30 00:53:30 -07001305 if (c == '\r') {
1306 if (I_IGNCR(tty))
Peter Hurleye60d27c2013-07-24 08:29:56 -04001307 return 0;
Joe Peterson575537b32008-04-30 00:53:30 -07001308 if (I_ICRNL(tty))
1309 c = '\n';
1310 } else if (c == '\n' && I_INLCR(tty))
1311 c = '\r';
1312
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001313 if (ldata->icanon) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314 if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
1315 (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
1316 eraser(c, tty);
Peter Hurley17bd7902013-06-15 10:04:24 -04001317 commit_echoes(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001318 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319 }
1320 if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001321 ldata->lnext = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 if (L_ECHO(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001323 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001324 if (L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001325 echo_char_raw('^', ldata);
1326 echo_char_raw('\b', ldata);
Peter Hurley17bd7902013-06-15 10:04:24 -04001327 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 }
1329 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001330 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001332 if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001333 size_t tail = ldata->canon_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334
Jiri Slaby57c94122012-10-18 22:26:43 +02001335 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336 echo_char(c, tty);
Jiri Slaby57c94122012-10-18 22:26:43 +02001337 echo_char_raw('\n', ldata);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001338 while (tail != ldata->read_head) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001339 echo_char(read_buf(ldata, tail), tty);
1340 tail++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001341 }
Peter Hurley17bd7902013-06-15 10:04:24 -04001342 commit_echoes(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001343 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344 }
1345 if (c == '\n') {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001346 if (L_ECHO(tty) || L_ECHONL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001347 echo_char_raw('\n', ldata);
Peter Hurley17bd7902013-06-15 10:04:24 -04001348 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349 }
1350 goto handle_newline;
1351 }
1352 if (c == EOF_CHAR(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353 c = __DISABLED_CHAR;
1354 goto handle_newline;
1355 }
1356 if ((c == EOL_CHAR(tty)) ||
1357 (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
1358 /*
1359 * XXX are EOL_CHAR and EOL2_CHAR echoed?!?
1360 */
1361 if (L_ECHO(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001362 /* Record the column of first canon char. */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001363 if (ldata->canon_head == ldata->read_head)
Jiri Slaby57c94122012-10-18 22:26:43 +02001364 echo_set_canon_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365 echo_char(c, tty);
Peter Hurley17bd7902013-06-15 10:04:24 -04001366 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001367 }
1368 /*
1369 * XXX does PARMRK doubling happen for
1370 * EOL_CHAR and EOL2_CHAR?
1371 */
Peter Hurley001ba922013-12-02 14:24:44 -05001372 if (c == (unsigned char) '\377' && I_PARMRK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001373 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001374
Alan Cox4edf1822008-02-08 04:18:44 -08001375handle_newline:
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001376 set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags);
Peter Hurley6d76bd22013-06-15 09:14:26 -04001377 put_tty_queue(c, ldata);
Peter Hurley70aca712015-01-16 15:05:37 -05001378 smp_store_release(&ldata->canon_head, ldata->read_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001379 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
Kosuke Tatsukawae81107d2015-10-02 08:27:05 +00001380 wake_up_interruptible_poll(&tty->read_wait, POLLIN);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001381 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382 }
1383 }
Alan Cox4edf1822008-02-08 04:18:44 -08001384
Joe Petersonacc71bb2009-01-02 13:43:32 +00001385 if (L_ECHO(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001386 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387 if (c == '\n')
Jiri Slaby57c94122012-10-18 22:26:43 +02001388 echo_char_raw('\n', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389 else {
1390 /* Record the column of first canon char. */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001391 if (ldata->canon_head == ldata->read_head)
Jiri Slaby57c94122012-10-18 22:26:43 +02001392 echo_set_canon_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001393 echo_char(c, tty);
1394 }
Peter Hurley17bd7902013-06-15 10:04:24 -04001395 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001396 }
1397
Peter Hurley001ba922013-12-02 14:24:44 -05001398 /* PARMRK doubling check */
1399 if (c == (unsigned char) '\377' && I_PARMRK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001400 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401
Jiri Slaby57c94122012-10-18 22:26:43 +02001402 put_tty_queue(c, ldata);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001403 return 0;
Alan Cox4edf1822008-02-08 04:18:44 -08001404}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405
Peter Hurleye60d27c2013-07-24 08:29:56 -04001406static inline void
1407n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c)
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001408{
1409 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001410
Peter Hurleye60d27c2013-07-24 08:29:56 -04001411 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
1412 start_tty(tty);
1413 process_echoes(tty);
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001414 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001415 if (L_ECHO(tty)) {
1416 finish_erasing(ldata);
1417 /* Record the column of first canon char. */
1418 if (ldata->canon_head == ldata->read_head)
1419 echo_set_canon_col(ldata);
1420 echo_char(c, tty);
1421 commit_echoes(tty);
1422 }
Peter Hurley001ba922013-12-02 14:24:44 -05001423 /* PARMRK doubling check */
1424 if (c == (unsigned char) '\377' && I_PARMRK(tty))
Peter Hurleye60d27c2013-07-24 08:29:56 -04001425 put_tty_queue(c, ldata);
1426 put_tty_queue(c, ldata);
1427}
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001428
Peter Hurleyeb3e4662013-12-02 14:24:42 -05001429static void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
Peter Hurleye60d27c2013-07-24 08:29:56 -04001430{
1431 n_tty_receive_char_inline(tty, c);
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001432}
1433
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001434static inline void
Peter Hurley7de971b2013-07-24 08:29:53 -04001435n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c)
1436{
1437 struct n_tty_data *ldata = tty->disc_data;
1438
Peter Hurleye60d27c2013-07-24 08:29:56 -04001439 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
1440 start_tty(tty);
1441 process_echoes(tty);
Peter Hurley7de971b2013-07-24 08:29:53 -04001442 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001443 if (L_ECHO(tty)) {
1444 finish_erasing(ldata);
1445 /* Record the column of first canon char. */
1446 if (ldata->canon_head == ldata->read_head)
1447 echo_set_canon_col(ldata);
1448 echo_char(c, tty);
1449 commit_echoes(tty);
1450 }
1451 put_tty_queue(c, ldata);
Peter Hurley7de971b2013-07-24 08:29:53 -04001452}
1453
Peter Hurley8dc4b252013-12-02 14:24:43 -05001454static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c)
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001455{
1456 if (I_ISTRIP(tty))
1457 c &= 0x7f;
1458 if (I_IUCLC(tty) && L_IEXTEN(tty))
1459 c = tolower(c);
1460
1461 if (I_IXON(tty)) {
1462 if (c == STOP_CHAR(tty))
1463 stop_tty(tty);
1464 else if (c == START_CHAR(tty) ||
1465 (tty->stopped && !tty->flow_stopped && I_IXANY(tty) &&
1466 c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) &&
1467 c != SUSP_CHAR(tty))) {
1468 start_tty(tty);
1469 process_echoes(tty);
1470 }
1471 }
1472}
1473
Peter Hurleyd2f8d7a2013-06-15 10:21:24 -04001474static void
1475n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag)
1476{
Peter Hurleyd2f8d7a2013-06-15 10:21:24 -04001477 switch (flag) {
1478 case TTY_BREAK:
1479 n_tty_receive_break(tty);
1480 break;
1481 case TTY_PARITY:
1482 case TTY_FRAME:
1483 n_tty_receive_parity_error(tty, c);
1484 break;
1485 case TTY_OVERRUN:
1486 n_tty_receive_overrun(tty);
1487 break;
1488 default:
1489 printk(KERN_ERR "%s: unknown flag %d\n",
Rasmus Villemoes429b4742015-03-31 15:55:59 +02001490 tty_name(tty), flag);
Peter Hurleyd2f8d7a2013-06-15 10:21:24 -04001491 break;
1492 }
1493}
1494
Peter Hurleye60d27c2013-07-24 08:29:56 -04001495static void
1496n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag)
1497{
1498 struct n_tty_data *ldata = tty->disc_data;
1499
1500 ldata->lnext = 0;
1501 if (likely(flag == TTY_NORMAL)) {
1502 if (I_ISTRIP(tty))
1503 c &= 0x7f;
1504 if (I_IUCLC(tty) && L_IEXTEN(tty))
1505 c = tolower(c);
1506 n_tty_receive_char(tty, c);
1507 } else
1508 n_tty_receive_char_flagged(tty, c, flag);
1509}
1510
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001511static void
1512n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp,
1513 char *fp, int count)
1514{
1515 struct n_tty_data *ldata = tty->disc_data;
1516 size_t n, head;
1517
1518 head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
Peter Hurley70aca712015-01-16 15:05:37 -05001519 n = min_t(size_t, count, N_TTY_BUF_SIZE - head);
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001520 memcpy(read_buf_addr(ldata, head), cp, n);
1521 ldata->read_head += n;
1522 cp += n;
1523 count -= n;
1524
1525 head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
Peter Hurley70aca712015-01-16 15:05:37 -05001526 n = min_t(size_t, count, N_TTY_BUF_SIZE - head);
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001527 memcpy(read_buf_addr(ldata, head), cp, n);
1528 ldata->read_head += n;
1529}
1530
Peter Hurley554117b2013-06-15 10:21:25 -04001531static void
1532n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp,
1533 char *fp, int count)
1534{
1535 struct n_tty_data *ldata = tty->disc_data;
1536 char flag = TTY_NORMAL;
1537
1538 while (count--) {
1539 if (fp)
1540 flag = *fp++;
1541 if (likely(flag == TTY_NORMAL))
1542 put_tty_queue(*cp++, ldata);
1543 else
1544 n_tty_receive_char_flagged(tty, *cp++, flag);
1545 }
1546}
1547
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001548static void
1549n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp,
1550 char *fp, int count)
1551{
1552 char flag = TTY_NORMAL;
1553
1554 while (count--) {
1555 if (fp)
1556 flag = *fp++;
1557 if (likely(flag == TTY_NORMAL))
1558 n_tty_receive_char_closing(tty, *cp++);
1559 else
1560 n_tty_receive_char_flagged(tty, *cp++, flag);
1561 }
1562}
1563
Peter Hurley7d88d632013-07-24 08:29:49 -04001564static void
1565n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp,
Peter Hurley6baad002013-07-24 08:29:52 -04001566 char *fp, int count)
1567{
1568 struct n_tty_data *ldata = tty->disc_data;
1569 char flag = TTY_NORMAL;
1570
1571 while (count--) {
1572 if (fp)
1573 flag = *fp++;
1574 if (likely(flag == TTY_NORMAL)) {
1575 unsigned char c = *cp++;
1576
1577 if (I_ISTRIP(tty))
1578 c &= 0x7f;
1579 if (I_IUCLC(tty) && L_IEXTEN(tty))
1580 c = tolower(c);
1581 if (L_EXTPROC(tty)) {
1582 put_tty_queue(c, ldata);
1583 continue;
1584 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001585 if (!test_bit(c, ldata->char_map))
1586 n_tty_receive_char_inline(tty, c);
1587 else if (n_tty_receive_char_special(tty, c) && count) {
1588 if (fp)
1589 flag = *fp++;
1590 n_tty_receive_char_lnext(tty, *cp++, flag);
1591 count--;
1592 }
Peter Hurley6baad002013-07-24 08:29:52 -04001593 } else
1594 n_tty_receive_char_flagged(tty, *cp++, flag);
1595 }
1596}
1597
1598static void
1599n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp,
1600 char *fp, int count)
Peter Hurley7d88d632013-07-24 08:29:49 -04001601{
Peter Hurleye60d27c2013-07-24 08:29:56 -04001602 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley7d88d632013-07-24 08:29:49 -04001603 char flag = TTY_NORMAL;
1604
1605 while (count--) {
1606 if (fp)
1607 flag = *fp++;
Peter Hurleye60d27c2013-07-24 08:29:56 -04001608 if (likely(flag == TTY_NORMAL)) {
1609 unsigned char c = *cp++;
1610
1611 if (!test_bit(c, ldata->char_map))
1612 n_tty_receive_char_fast(tty, c);
1613 else if (n_tty_receive_char_special(tty, c) && count) {
1614 if (fp)
1615 flag = *fp++;
1616 n_tty_receive_char_lnext(tty, *cp++, flag);
1617 count--;
1618 }
1619 } else
Peter Hurley7d88d632013-07-24 08:29:49 -04001620 n_tty_receive_char_flagged(tty, *cp++, flag);
1621 }
1622}
1623
Peter Hurley24a89d12013-06-15 09:14:15 -04001624static void __receive_buf(struct tty_struct *tty, const unsigned char *cp,
1625 char *fp, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001626{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001627 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleya1dd30e2013-06-15 10:21:26 -04001628 bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001629
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001630 if (ldata->real_raw)
1631 n_tty_receive_buf_real_raw(tty, cp, fp, count);
Peter Hurleya1dd30e2013-06-15 10:21:26 -04001632 else if (ldata->raw || (L_EXTPROC(tty) && !preops))
Peter Hurley554117b2013-06-15 10:21:25 -04001633 n_tty_receive_buf_raw(tty, cp, fp, count);
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001634 else if (tty->closing && !L_EXTPROC(tty))
1635 n_tty_receive_buf_closing(tty, cp, fp, count);
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001636 else {
Peter Hurleye60d27c2013-07-24 08:29:56 -04001637 if (ldata->lnext) {
1638 char flag = TTY_NORMAL;
1639
1640 if (fp)
1641 flag = *fp++;
1642 n_tty_receive_char_lnext(tty, *cp++, flag);
1643 count--;
1644 }
1645
Peter Hurley7de971b2013-07-24 08:29:53 -04001646 if (!preops && !I_PARMRK(tty))
Peter Hurley6baad002013-07-24 08:29:52 -04001647 n_tty_receive_buf_fast(tty, cp, fp, count);
1648 else
1649 n_tty_receive_buf_standard(tty, cp, fp, count);
Peter Hurleycbfd0342013-06-15 10:04:26 -04001650
1651 flush_echoes(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001652 if (tty->ops->flush_chars)
1653 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001654 }
1655
Peter Hurley70aca712015-01-16 15:05:37 -05001656 if (ldata->icanon && !L_EXTPROC(tty))
1657 return;
1658
1659 /* publish read_head to consumer */
1660 smp_store_release(&ldata->commit_head, ldata->read_head);
1661
1662 if ((read_cnt(ldata) >= ldata->minimum_to_wake) || L_EXTPROC(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001663 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
Kosuke Tatsukawae81107d2015-10-02 08:27:05 +00001664 wake_up_interruptible_poll(&tty->read_wait, POLLIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001665 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666}
1667
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001668/**
1669 * n_tty_receive_buf_common - process input
1670 * @tty: device to receive input
1671 * @cp: input chars
1672 * @fp: flags for each char (if NULL, all chars are TTY_NORMAL)
1673 * @count: number of input chars in @cp
1674 *
1675 * Called by the terminal driver when a block of characters has
1676 * been received. This function must be called from soft contexts
1677 * not from interrupt context. The driver is responsible for making
1678 * calls one at a time and in order (or using flush_to_ldisc)
1679 *
1680 * Returns the # of input chars from @cp which were processed.
1681 *
1682 * In canonical mode, the maximum line length is 4096 chars (including
1683 * the line termination char); lines longer than 4096 chars are
1684 * truncated. After 4095 chars, input data is still processed but
1685 * not stored. Overflow processing ensures the tty can always
1686 * receive more input until at least one line can be read.
1687 *
1688 * In non-canonical mode, the read buffer will only accept 4095 chars;
1689 * this provides the necessary space for a newline char if the input
1690 * mode is switched to canonical.
1691 *
1692 * Note it is possible for the read buffer to _contain_ 4096 chars
1693 * in non-canonical mode: the read buffer could already contain the
1694 * maximum canon line of 4096 chars when the mode is switched to
1695 * non-canonical.
1696 *
1697 * n_tty_receive_buf()/producer path:
1698 * claims non-exclusive termios_rwsem
1699 * publishes commit_head or canon_head
1700 */
Peter Hurley5c32d122013-12-02 14:24:41 -05001701static int
1702n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
1703 char *fp, int count, int flow)
Peter Hurley24a89d12013-06-15 09:14:15 -04001704{
1705 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001706 int room, n, rcvd = 0, overflow;
Peter Hurley24a89d12013-06-15 09:14:15 -04001707
Peter Hurley9356b532013-06-15 09:14:24 -04001708 down_read(&tty->termios_rwsem);
1709
Peter Hurley19e2ad62013-07-24 08:29:54 -04001710 while (1) {
Peter Hurley70aca712015-01-16 15:05:37 -05001711 /*
Peter Hurley06c49f92015-01-16 15:05:38 -05001712 * When PARMRK is set, each input char may take up to 3 chars
1713 * in the read buf; reduce the buffer space avail by 3x
Peter Hurley70aca712015-01-16 15:05:37 -05001714 *
1715 * If we are doing input canonicalization, and there are no
1716 * pending newlines, let characters through without limit, so
1717 * that erase characters will be handled. Other excess
1718 * characters will be beeped.
1719 *
1720 * paired with store in *_copy_from_read_buf() -- guarantees
1721 * the consumer has loaded the data in read_buf up to the new
1722 * read_tail (so this producer will not overwrite unread data)
1723 */
1724 size_t tail = smp_load_acquire(&ldata->read_tail);
Peter Hurley70aca712015-01-16 15:05:37 -05001725
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001726 room = N_TTY_BUF_SIZE - (ldata->read_head - tail);
Peter Hurley70aca712015-01-16 15:05:37 -05001727 if (I_PARMRK(tty))
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001728 room = (room + 2) / 3;
1729 room--;
1730 if (room <= 0) {
1731 overflow = ldata->icanon && ldata->canon_head == tail;
1732 if (overflow && room < 0)
1733 ldata->read_head--;
1734 room = overflow;
1735 ldata->no_room = flow && !room;
1736 } else
1737 overflow = 0;
Peter Hurley70aca712015-01-16 15:05:37 -05001738
Peter Hurley19e2ad62013-07-24 08:29:54 -04001739 n = min(count, room);
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001740 if (!n)
Peter Hurley19e2ad62013-07-24 08:29:54 -04001741 break;
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001742
1743 /* ignore parity errors if handling overflow */
1744 if (!overflow || !fp || *fp != TTY_PARITY)
1745 __receive_buf(tty, cp, fp, n);
1746
Peter Hurley19e2ad62013-07-24 08:29:54 -04001747 cp += n;
1748 if (fp)
1749 fp += n;
1750 count -= n;
1751 rcvd += n;
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001752 }
Peter Hurley24a89d12013-06-15 09:14:15 -04001753
Peter Hurley19e2ad62013-07-24 08:29:54 -04001754 tty->receive_room = room;
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001755
1756 /* Unthrottle if handling overflow on pty */
1757 if (tty->driver->type == TTY_DRIVER_TYPE_PTY) {
1758 if (overflow) {
1759 tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE);
1760 tty_unthrottle_safe(tty);
1761 __tty_set_flow_change(tty, 0);
1762 }
1763 } else
1764 n_tty_check_throttle(tty);
1765
Peter Hurley9356b532013-06-15 09:14:24 -04001766 up_read(&tty->termios_rwsem);
1767
Peter Hurley19e2ad62013-07-24 08:29:54 -04001768 return rcvd;
Peter Hurley24a89d12013-06-15 09:14:15 -04001769}
1770
Peter Hurley5c32d122013-12-02 14:24:41 -05001771static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1772 char *fp, int count)
1773{
1774 n_tty_receive_buf_common(tty, cp, fp, count, 0);
1775}
1776
1777static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp,
1778 char *fp, int count)
1779{
1780 return n_tty_receive_buf_common(tty, cp, fp, count, 1);
1781}
1782
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783int is_ignored(int sig)
1784{
1785 return (sigismember(&current->blocked, sig) ||
Alan Cox4edf1822008-02-08 04:18:44 -08001786 current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787}
1788
1789/**
1790 * n_tty_set_termios - termios data changed
1791 * @tty: terminal
1792 * @old: previous data
1793 *
1794 * Called by the tty layer when the user changes termios flags so
1795 * that the line discipline can plan ahead. This function cannot sleep
Alan Cox4edf1822008-02-08 04:18:44 -08001796 * and is protected from re-entry by the tty layer. The user is
Linus Torvalds1da177e2005-04-16 15:20:36 -07001797 * guaranteed that this function will not be re-entered or in progress
1798 * when the ldisc is closed.
Alan Cox17b82062008-10-13 10:45:06 +01001799 *
Peter Hurley6a1c0682013-06-15 09:14:23 -04001800 * Locking: Caller holds tty->termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001801 */
Alan Cox4edf1822008-02-08 04:18:44 -08001802
1803static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001804{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001805 struct n_tty_data *ldata = tty->disc_data;
Alan Cox47afa7a2008-10-13 10:44:17 +01001806
Peter Hurleyc786f742013-09-17 12:53:35 -04001807 if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) {
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001808 bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
Peter Hurley4d0ed182013-12-10 17:12:02 -05001809 ldata->line_start = ldata->read_tail;
1810 if (!L_ICANON(tty) || !read_cnt(ldata)) {
1811 ldata->canon_head = ldata->read_tail;
1812 ldata->push = 0;
1813 } else {
1814 set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1),
1815 ldata->read_flags);
1816 ldata->canon_head = ldata->read_head;
1817 ldata->push = 1;
1818 }
Peter Hurley70aca712015-01-16 15:05:37 -05001819 ldata->commit_head = ldata->read_head;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001820 ldata->erasing = 0;
Peter Hurley6f9b0282013-06-15 09:14:27 -04001821 ldata->lnext = 0;
Alan Cox47afa7a2008-10-13 10:44:17 +01001822 }
1823
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001824 ldata->icanon = (L_ICANON(tty) != 0);
Peter Hurley582f5592013-05-17 12:49:48 -04001825
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826 if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
1827 I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
1828 I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
1829 I_PARMRK(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001830 bitmap_zero(ldata->char_map, 256);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831
1832 if (I_IGNCR(tty) || I_ICRNL(tty))
Peter Hurley1bb9d562013-06-15 10:21:20 -04001833 set_bit('\r', ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834 if (I_INLCR(tty))
Peter Hurley1bb9d562013-06-15 10:21:20 -04001835 set_bit('\n', ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001836
1837 if (L_ICANON(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001838 set_bit(ERASE_CHAR(tty), ldata->char_map);
1839 set_bit(KILL_CHAR(tty), ldata->char_map);
1840 set_bit(EOF_CHAR(tty), ldata->char_map);
1841 set_bit('\n', ldata->char_map);
1842 set_bit(EOL_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001843 if (L_IEXTEN(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001844 set_bit(WERASE_CHAR(tty), ldata->char_map);
1845 set_bit(LNEXT_CHAR(tty), ldata->char_map);
1846 set_bit(EOL2_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001847 if (L_ECHO(tty))
1848 set_bit(REPRINT_CHAR(tty),
Peter Hurley1bb9d562013-06-15 10:21:20 -04001849 ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001850 }
1851 }
1852 if (I_IXON(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001853 set_bit(START_CHAR(tty), ldata->char_map);
1854 set_bit(STOP_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001855 }
1856 if (L_ISIG(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001857 set_bit(INTR_CHAR(tty), ldata->char_map);
1858 set_bit(QUIT_CHAR(tty), ldata->char_map);
1859 set_bit(SUSP_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001860 }
Peter Hurley1bb9d562013-06-15 10:21:20 -04001861 clear_bit(__DISABLED_CHAR, ldata->char_map);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001862 ldata->raw = 0;
1863 ldata->real_raw = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001864 } else {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001865 ldata->raw = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866 if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
1867 (I_IGNPAR(tty) || !I_INPCK(tty)) &&
1868 (tty->driver->flags & TTY_DRIVER_REAL_RAW))
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001869 ldata->real_raw = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001870 else
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001871 ldata->real_raw = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001872 }
Wang YanQingdab73b42013-05-09 14:16:47 +08001873 /*
1874 * Fix tty hang when I_IXON(tty) is cleared, but the tty
1875 * been stopped by STOP_CHAR(tty) before it.
1876 */
Peter Hurleye2613be2014-02-11 16:34:55 -05001877 if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) {
Wang YanQingdab73b42013-05-09 14:16:47 +08001878 start_tty(tty);
Peter Hurleye2613be2014-02-11 16:34:55 -05001879 process_echoes(tty);
1880 }
Wang YanQingdab73b42013-05-09 14:16:47 +08001881
Alan Coxf34d7a52008-04-30 00:54:13 -07001882 /* The termios change make the tty ready for I/O */
Kosuke Tatsukawae81107d2015-10-02 08:27:05 +00001883 wake_up_interruptible(&tty->write_wait);
1884 wake_up_interruptible(&tty->read_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885}
1886
1887/**
1888 * n_tty_close - close the ldisc for this tty
1889 * @tty: device
1890 *
Alan Cox4edf1822008-02-08 04:18:44 -08001891 * Called from the terminal layer when this line discipline is
1892 * being shut down, either because of a close or becsuse of a
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893 * discipline change. The function will not be called while other
1894 * ldisc methods are in progress.
1895 */
Alan Cox4edf1822008-02-08 04:18:44 -08001896
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897static void n_tty_close(struct tty_struct *tty)
1898{
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001899 struct n_tty_data *ldata = tty->disc_data;
1900
Peter Hurley79901312013-03-11 16:44:23 -04001901 if (tty->link)
1902 n_tty_packet_mode_flush(tty);
1903
Peter Hurley20bafb32013-06-15 10:21:19 -04001904 vfree(ldata);
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001905 tty->disc_data = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001906}
1907
1908/**
1909 * n_tty_open - open an ldisc
1910 * @tty: terminal to open
1911 *
Alan Cox4edf1822008-02-08 04:18:44 -08001912 * Called when this line discipline is being attached to the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001913 * terminal device. Can sleep. Called serialized so that no
1914 * other events will occur in parallel. No further open will occur
1915 * until a close.
1916 */
1917
1918static int n_tty_open(struct tty_struct *tty)
1919{
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001920 struct n_tty_data *ldata;
1921
Peter Hurley20bafb32013-06-15 10:21:19 -04001922 /* Currently a malloc failure here can panic */
1923 ldata = vmalloc(sizeof(*ldata));
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001924 if (!ldata)
1925 goto err;
1926
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001927 ldata->overrun_time = jiffies;
Jiri Slabybddc7152012-10-18 22:26:42 +02001928 mutex_init(&ldata->atomic_read_lock);
1929 mutex_init(&ldata->output_lock);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001930
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001931 tty->disc_data = ldata;
Peter Hurleyb66f4fa2013-03-11 16:44:32 -04001932 reset_buffer_flags(tty->disc_data);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001933 ldata->column = 0;
Peter Hurley20bafb32013-06-15 10:21:19 -04001934 ldata->canon_column = 0;
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04001935 ldata->minimum_to_wake = 1;
Peter Hurley20bafb32013-06-15 10:21:19 -04001936 ldata->num_overrun = 0;
1937 ldata->no_room = 0;
1938 ldata->lnext = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001939 tty->closing = 0;
Peter Hurleyb66f4fa2013-03-11 16:44:32 -04001940 /* indicate buffer work may resume */
1941 clear_bit(TTY_LDISC_HALTED, &tty->flags);
1942 n_tty_set_termios(tty, NULL);
1943 tty_unthrottle(tty);
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001944
Linus Torvalds1da177e2005-04-16 15:20:36 -07001945 return 0;
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001946err:
Jiri Slabyb91939f2012-10-18 22:26:35 +02001947 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001948}
1949
Peter Hurleyeafbe672013-12-02 14:24:45 -05001950static inline int input_available_p(struct tty_struct *tty, int poll)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001951{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001952 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleya5934802014-02-11 11:49:58 -05001953 int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001954
Peter Hurley25e8d0e2014-02-11 18:55:30 -05001955 if (ldata->icanon && !L_EXTPROC(tty))
1956 return ldata->canon_head != ldata->read_tail;
1957 else
Peter Hurley70aca712015-01-16 15:05:37 -05001958 return ldata->commit_head - ldata->read_tail >= amt;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001959}
1960
Peter Hurley1a486322015-04-13 13:24:34 -04001961static inline int check_other_done(struct tty_struct *tty)
1962{
1963 int done = test_bit(TTY_OTHER_DONE, &tty->flags);
1964 if (done) {
1965 /* paired with cmpxchg() in check_other_closed(); ensures
1966 * read buffer head index is not stale
1967 */
1968 smp_mb__after_atomic();
1969 }
1970 return done;
1971}
1972
Linus Torvalds1da177e2005-04-16 15:20:36 -07001973/**
Thorsten Wißmannbbd20752011-12-08 17:47:33 +01001974 * copy_from_read_buf - copy read data directly
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975 * @tty: terminal device
1976 * @b: user data
1977 * @nr: size of data
1978 *
Alan Cox11a96d12008-10-13 10:46:24 +01001979 * Helper function to speed up n_tty_read. It is only called when
Linus Torvalds1da177e2005-04-16 15:20:36 -07001980 * ICANON is off; it copies characters straight from the tty queue to
1981 * user space directly. It can be profitably called twice; once to
1982 * drain the space from the tail pointer to the (physical) end of the
1983 * buffer, and once to drain the space from the (physical) beginning of
1984 * the buffer to head pointer.
1985 *
Jiri Slabybddc7152012-10-18 22:26:42 +02001986 * Called under the ldata->atomic_read_lock sem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001987 *
Peter Hurley6d76bd22013-06-15 09:14:26 -04001988 * n_tty_read()/consumer path:
1989 * caller holds non-exclusive termios_rwsem
1990 * read_tail published
Linus Torvalds1da177e2005-04-16 15:20:36 -07001991 */
Alan Cox4edf1822008-02-08 04:18:44 -08001992
Alan Cox33f0f882006-01-09 20:54:13 -08001993static int copy_from_read_buf(struct tty_struct *tty,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994 unsigned char __user **b,
1995 size_t *nr)
1996
1997{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001998 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001999 int retval;
2000 size_t n;
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02002001 bool is_eof;
Peter Hurley70aca712015-01-16 15:05:37 -05002002 size_t head = smp_load_acquire(&ldata->commit_head);
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002003 size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002004
2005 retval = 0;
Peter Hurley70aca712015-01-16 15:05:37 -05002006 n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002007 n = min(*nr, n);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002008 if (n) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002009 retval = copy_to_user(*b, read_buf_addr(ldata, tail), n);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002010 n -= retval;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002011 is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty);
2012 tty_audit_add_data(tty, read_buf_addr(ldata, tail), n,
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002013 ldata->icanon);
Peter Hurley70aca712015-01-16 15:05:37 -05002014 smp_store_release(&ldata->read_tail, ldata->read_tail + n);
hyc@symas.com26df6d12010-06-22 10:14:49 -07002015 /* Turn single EOF into zero-length read */
Peter Hurley70aca712015-01-16 15:05:37 -05002016 if (L_EXTPROC(tty) && ldata->icanon && is_eof &&
2017 (head == ldata->read_tail))
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02002018 n = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002019 *b += n;
2020 *nr -= n;
2021 }
2022 return retval;
2023}
2024
Peter Hurley88bb0de2013-06-15 09:14:16 -04002025/**
Peter Hurley32f13522013-06-15 09:14:17 -04002026 * canon_copy_from_read_buf - copy read data in canonical mode
Peter Hurley88bb0de2013-06-15 09:14:16 -04002027 * @tty: terminal device
2028 * @b: user data
2029 * @nr: size of data
2030 *
2031 * Helper function for n_tty_read. It is only called when ICANON is on;
Peter Hurley32f13522013-06-15 09:14:17 -04002032 * it copies one line of input up to and including the line-delimiting
2033 * character into the user-space buffer.
Peter Hurley88bb0de2013-06-15 09:14:16 -04002034 *
Peter Hurley4d0ed182013-12-10 17:12:02 -05002035 * NB: When termios is changed from non-canonical to canonical mode and
2036 * the read buffer contains data, n_tty_set_termios() simulates an EOF
2037 * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer.
2038 * This causes data already processed as input to be immediately available
2039 * as input although a newline has not been received.
2040 *
Peter Hurley88bb0de2013-06-15 09:14:16 -04002041 * Called under the atomic_read_lock mutex
Peter Hurley6d76bd22013-06-15 09:14:26 -04002042 *
2043 * n_tty_read()/consumer path:
2044 * caller holds non-exclusive termios_rwsem
2045 * read_tail published
Peter Hurley88bb0de2013-06-15 09:14:16 -04002046 */
2047
Peter Hurley32f13522013-06-15 09:14:17 -04002048static int canon_copy_from_read_buf(struct tty_struct *tty,
2049 unsigned char __user **b,
2050 size_t *nr)
Peter Hurley88bb0de2013-06-15 09:14:16 -04002051{
2052 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley32f13522013-06-15 09:14:17 -04002053 size_t n, size, more, c;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002054 size_t eol;
2055 size_t tail;
2056 int ret, found = 0;
Peter Hurley40d5e092013-06-15 10:21:17 -04002057 bool eof_push = 0;
Peter Hurley88bb0de2013-06-15 09:14:16 -04002058
2059 /* N.B. avoid overrun if nr == 0 */
Peter Hurley70aca712015-01-16 15:05:37 -05002060 n = min(*nr, smp_load_acquire(&ldata->canon_head) - ldata->read_tail);
Peter Hurley6d76bd22013-06-15 09:14:26 -04002061 if (!n)
Peter Hurley32f13522013-06-15 09:14:17 -04002062 return 0;
Peter Hurley88bb0de2013-06-15 09:14:16 -04002063
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002064 tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
Peter Hurley32f13522013-06-15 09:14:17 -04002065 size = min_t(size_t, tail + n, N_TTY_BUF_SIZE);
2066
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002067 n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n",
Peter Hurley32f13522013-06-15 09:14:17 -04002068 __func__, *nr, tail, n, size);
2069
2070 eol = find_next_bit(ldata->read_flags, size, tail);
2071 more = n - (size - tail);
2072 if (eol == N_TTY_BUF_SIZE && more) {
2073 /* scan wrapped without finding set bit */
2074 eol = find_next_bit(ldata->read_flags, more, 0);
2075 if (eol != more)
2076 found = 1;
2077 } else if (eol != size)
2078 found = 1;
2079
2080 size = N_TTY_BUF_SIZE - tail;
Peter Hurleyc77569d2013-11-22 07:16:25 -05002081 n = eol - tail;
Mark Tomlinsonda555db2015-05-18 12:01:48 +12002082 if (n > N_TTY_BUF_SIZE)
2083 n += N_TTY_BUF_SIZE;
Peter Hurleyc77569d2013-11-22 07:16:25 -05002084 n += found;
Peter Hurley32f13522013-06-15 09:14:17 -04002085 c = n;
2086
Peter Hurley4d0ed182013-12-10 17:12:02 -05002087 if (found && !ldata->push && read_buf(ldata, eol) == __DISABLED_CHAR) {
Peter Hurley32f13522013-06-15 09:14:17 -04002088 n--;
Peter Hurley40d5e092013-06-15 10:21:17 -04002089 eof_push = !n && ldata->read_tail != ldata->line_start;
2090 }
Peter Hurley32f13522013-06-15 09:14:17 -04002091
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002092 n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n",
Peter Hurley32f13522013-06-15 09:14:17 -04002093 __func__, eol, found, n, c, size, more);
2094
Peter Hurley32f13522013-06-15 09:14:17 -04002095 if (n > size) {
Laura Abbott72586c62015-05-14 11:42:17 -07002096 ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), size);
Peter Hurley32f13522013-06-15 09:14:17 -04002097 if (ret)
2098 return -EFAULT;
Laura Abbott72586c62015-05-14 11:42:17 -07002099 ret = tty_copy_to_user(tty, *b + size, ldata->read_buf, n - size);
Peter Hurley32f13522013-06-15 09:14:17 -04002100 } else
Laura Abbott72586c62015-05-14 11:42:17 -07002101 ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), n);
Peter Hurley32f13522013-06-15 09:14:17 -04002102
2103 if (ret)
2104 return -EFAULT;
2105 *b += n;
2106 *nr -= n;
2107
Peter Hurleya73d3d62013-06-15 09:14:25 -04002108 if (found)
Peter Hurley6d76bd22013-06-15 09:14:26 -04002109 clear_bit(eol, ldata->read_flags);
Peter Hurley70aca712015-01-16 15:05:37 -05002110 smp_store_release(&ldata->read_tail, ldata->read_tail + c);
Peter Hurley88bb0de2013-06-15 09:14:16 -04002111
Peter Hurley40d5e092013-06-15 10:21:17 -04002112 if (found) {
Peter Hurley4d0ed182013-12-10 17:12:02 -05002113 if (!ldata->push)
2114 ldata->line_start = ldata->read_tail;
2115 else
2116 ldata->push = 0;
Peter Hurley32f13522013-06-15 09:14:17 -04002117 tty_audit_push(tty);
Peter Hurley40d5e092013-06-15 10:21:17 -04002118 }
2119 return eof_push ? -EAGAIN : 0;
Peter Hurley88bb0de2013-06-15 09:14:16 -04002120}
2121
Al Virocc4191d2008-03-29 03:08:48 +00002122extern ssize_t redirected_tty_write(struct file *, const char __user *,
Alan Cox4edf1822008-02-08 04:18:44 -08002123 size_t, loff_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002124
2125/**
2126 * job_control - check job control
2127 * @tty: tty
2128 * @file: file handle
2129 *
2130 * Perform job control management checks on this file/tty descriptor
Alan Cox4edf1822008-02-08 04:18:44 -08002131 * and if appropriate send any needed signals and return a negative
Linus Torvalds1da177e2005-04-16 15:20:36 -07002132 * error code if action should be taken.
Alan Cox04f378b2008-04-30 00:53:29 -07002133 *
Peter Hurley01a5e442013-03-06 08:38:20 -05002134 * Locking: redirected write test is safe
2135 * current->signal->tty check is safe
2136 * ctrl_lock to safely reference tty->pgrp
Linus Torvalds1da177e2005-04-16 15:20:36 -07002137 */
Alan Cox4edf1822008-02-08 04:18:44 -08002138
Linus Torvalds1da177e2005-04-16 15:20:36 -07002139static int job_control(struct tty_struct *tty, struct file *file)
2140{
2141 /* Job control check -- must be done at start and after
2142 every sleep (POSIX.1 7.1.1.4). */
2143 /* NOTE: not yet done after every sleep pending a thorough
2144 check of the logic of this change. -- jlc */
2145 /* don't stop on /dev/console */
Peter Hurley2812d9e2015-10-10 20:28:42 -04002146 if (file->f_op->write == redirected_tty_write)
Peter Hurley01a5e442013-03-06 08:38:20 -05002147 return 0;
2148
Peter Hurley2812d9e2015-10-10 20:28:42 -04002149 return __tty_check_change(tty, SIGTTIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002150}
Alan Cox4edf1822008-02-08 04:18:44 -08002151
Linus Torvalds1da177e2005-04-16 15:20:36 -07002152
2153/**
Alan Cox11a96d12008-10-13 10:46:24 +01002154 * n_tty_read - read function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07002155 * @tty: tty device
2156 * @file: file object
2157 * @buf: userspace buffer pointer
2158 * @nr: size of I/O
2159 *
2160 * Perform reads for the line discipline. We are guaranteed that the
2161 * line discipline will not be closed under us but we may get multiple
2162 * parallel readers and must handle this ourselves. We may also get
2163 * a hangup. Always called in user context, may sleep.
2164 *
2165 * This code must be sure never to sleep through a hangup.
Peter Hurley6d76bd22013-06-15 09:14:26 -04002166 *
2167 * n_tty_read()/consumer path:
2168 * claims non-exclusive termios_rwsem
2169 * publishes read_tail
Linus Torvalds1da177e2005-04-16 15:20:36 -07002170 */
Alan Cox4edf1822008-02-08 04:18:44 -08002171
Alan Cox11a96d12008-10-13 10:46:24 +01002172static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002173 unsigned char __user *buf, size_t nr)
2174{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002175 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002176 unsigned char __user *b = buf;
Peter Zijlstra97d9e282014-09-24 10:18:51 +02002177 DEFINE_WAIT_FUNC(wait, woken_wake_function);
Peter Hurley1a486322015-04-13 13:24:34 -04002178 int c, done;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002179 int minimum, time;
2180 ssize_t retval = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002181 long timeout;
Alan Cox04f378b2008-04-30 00:53:29 -07002182 int packet;
Peter Hurley2c5dc462015-01-16 15:05:34 -05002183 size_t tail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002184
Linus Torvalds1da177e2005-04-16 15:20:36 -07002185 c = job_control(tty, file);
Alan Cox4edf1822008-02-08 04:18:44 -08002186 if (c < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002187 return c;
Alan Cox4edf1822008-02-08 04:18:44 -08002188
Peter Hurleyaefceaf2013-08-11 08:04:23 -04002189 /*
2190 * Internal serialization of reads.
2191 */
2192 if (file->f_flags & O_NONBLOCK) {
2193 if (!mutex_trylock(&ldata->atomic_read_lock))
2194 return -EAGAIN;
2195 } else {
2196 if (mutex_lock_interruptible(&ldata->atomic_read_lock))
2197 return -ERESTARTSYS;
2198 }
2199
Peter Hurley9356b532013-06-15 09:14:24 -04002200 down_read(&tty->termios_rwsem);
2201
Linus Torvalds1da177e2005-04-16 15:20:36 -07002202 minimum = time = 0;
2203 timeout = MAX_SCHEDULE_TIMEOUT;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002204 if (!ldata->icanon) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002205 minimum = MIN_CHAR(tty);
2206 if (minimum) {
Peter Hurleya6e54312013-06-15 07:28:29 -04002207 time = (HZ / 10) * TIME_CHAR(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002208 if (time)
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002209 ldata->minimum_to_wake = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002210 else if (!waitqueue_active(&tty->read_wait) ||
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002211 (ldata->minimum_to_wake > minimum))
2212 ldata->minimum_to_wake = minimum;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002213 } else {
Peter Hurleya6e54312013-06-15 07:28:29 -04002214 timeout = (HZ / 10) * TIME_CHAR(tty);
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002215 ldata->minimum_to_wake = minimum = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002216 }
2217 }
2218
Alan Cox04f378b2008-04-30 00:53:29 -07002219 packet = tty->packet;
Peter Hurley2c5dc462015-01-16 15:05:34 -05002220 tail = ldata->read_tail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002221
2222 add_wait_queue(&tty->read_wait, &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002223 while (nr) {
2224 /* First test for status change. */
Alan Cox04f378b2008-04-30 00:53:29 -07002225 if (packet && tty->link->ctrl_status) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002226 unsigned char cs;
2227 if (b != buf)
2228 break;
Peter Hurley6054c16e2014-10-16 15:33:25 -04002229 spin_lock_irq(&tty->link->ctrl_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002230 cs = tty->link->ctrl_status;
2231 tty->link->ctrl_status = 0;
Peter Hurley6054c16e2014-10-16 15:33:25 -04002232 spin_unlock_irq(&tty->link->ctrl_lock);
Miloslav Trmac522ed772007-07-15 23:40:56 -07002233 if (tty_put_user(tty, cs, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002234 retval = -EFAULT;
2235 b--;
2236 break;
2237 }
2238 nr--;
2239 break;
2240 }
Alan Cox4edf1822008-02-08 04:18:44 -08002241
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002242 if (((minimum - (b - buf)) < ldata->minimum_to_wake) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07002243 ((minimum - (b - buf)) >= 1))
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002244 ldata->minimum_to_wake = (minimum - (b - buf));
Alan Cox4edf1822008-02-08 04:18:44 -08002245
Peter Hurley1a486322015-04-13 13:24:34 -04002246 done = check_other_done(tty);
2247
Linus Torvalds1da177e2005-04-16 15:20:36 -07002248 if (!input_available_p(tty, 0)) {
Peter Hurley1a486322015-04-13 13:24:34 -04002249 if (done) {
Peter Hurley52bce7f2014-11-05 12:13:05 -05002250 retval = -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002251 break;
2252 }
Peter Hurley52bce7f2014-11-05 12:13:05 -05002253 if (tty_hung_up_p(file))
2254 break;
2255 if (!timeout)
2256 break;
2257 if (file->f_flags & O_NONBLOCK) {
2258 retval = -EAGAIN;
2259 break;
2260 }
2261 if (signal_pending(current)) {
2262 retval = -ERESTARTSYS;
2263 break;
2264 }
Peter Hurley52bce7f2014-11-05 12:13:05 -05002265 up_read(&tty->termios_rwsem);
2266
Linus Torvalds37da7bb2014-12-14 15:23:32 -08002267 timeout = wait_woken(&wait, TASK_INTERRUPTIBLE,
2268 timeout);
Peter Hurley52bce7f2014-11-05 12:13:05 -05002269
2270 down_read(&tty->termios_rwsem);
2271 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002272 }
2273
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002274 if (ldata->icanon && !L_EXTPROC(tty)) {
Peter Hurley32f13522013-06-15 09:14:17 -04002275 retval = canon_copy_from_read_buf(tty, &b, &nr);
Peter Hurley40d5e092013-06-15 10:21:17 -04002276 if (retval == -EAGAIN) {
2277 retval = 0;
2278 continue;
2279 } else if (retval)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002280 break;
2281 } else {
2282 int uncopied;
Peter Hurley95ea90d2014-10-16 15:33:30 -04002283
2284 /* Deal with packet mode. */
2285 if (packet && b == buf) {
2286 if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
2287 retval = -EFAULT;
2288 b--;
2289 break;
2290 }
2291 nr--;
2292 }
2293
Linus Torvalds1da177e2005-04-16 15:20:36 -07002294 uncopied = copy_from_read_buf(tty, &b, &nr);
2295 uncopied += copy_from_read_buf(tty, &b, &nr);
2296 if (uncopied) {
2297 retval = -EFAULT;
2298 break;
2299 }
2300 }
2301
Peter Hurley6367ca72013-06-15 09:14:33 -04002302 n_tty_check_unthrottle(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002303
2304 if (b - buf >= minimum)
2305 break;
2306 if (time)
2307 timeout = time;
2308 }
Peter Hurley2c5dc462015-01-16 15:05:34 -05002309 if (tail != ldata->read_tail)
2310 n_tty_kick_worker(tty);
Peter Hurley42458f42013-11-07 13:59:46 -05002311 up_read(&tty->termios_rwsem);
2312
Linus Torvalds1da177e2005-04-16 15:20:36 -07002313 remove_wait_queue(&tty->read_wait, &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002314 if (!waitqueue_active(&tty->read_wait))
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002315 ldata->minimum_to_wake = minimum;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002316
Peter Hurleyaebf04532013-11-07 14:01:57 -05002317 mutex_unlock(&ldata->atomic_read_lock);
2318
Peter Hurley40d5e092013-06-15 10:21:17 -04002319 if (b - buf)
2320 retval = b - buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002321
2322 return retval;
2323}
2324
2325/**
Alan Cox11a96d12008-10-13 10:46:24 +01002326 * n_tty_write - write function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07002327 * @tty: tty device
2328 * @file: file object
2329 * @buf: userspace buffer pointer
2330 * @nr: size of I/O
2331 *
Joe Petersona88a69c2009-01-02 13:40:53 +00002332 * Write function of the terminal device. This is serialized with
Linus Torvalds1da177e2005-04-16 15:20:36 -07002333 * respect to other write callers but not to termios changes, reads
Joe Petersona88a69c2009-01-02 13:40:53 +00002334 * and other such events. Since the receive code will echo characters,
2335 * thus calling driver write methods, the output_lock is used in
2336 * the output processing functions called here as well as in the
2337 * echo processing function to protect the column state and space
2338 * left in the buffer.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002339 *
2340 * This code must be sure never to sleep through a hangup.
Joe Petersona88a69c2009-01-02 13:40:53 +00002341 *
2342 * Locking: output_lock to protect column state and space left
2343 * (note that the process_output*() functions take this
2344 * lock themselves)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002345 */
Alan Cox4edf1822008-02-08 04:18:44 -08002346
Alan Cox11a96d12008-10-13 10:46:24 +01002347static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
Joe Petersona88a69c2009-01-02 13:40:53 +00002348 const unsigned char *buf, size_t nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002349{
2350 const unsigned char *b = buf;
Peter Zijlstra97d9e282014-09-24 10:18:51 +02002351 DEFINE_WAIT_FUNC(wait, woken_wake_function);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002352 int c;
2353 ssize_t retval = 0;
2354
2355 /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
2356 if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) {
2357 retval = tty_check_change(tty);
2358 if (retval)
2359 return retval;
2360 }
2361
Peter Hurley9356b532013-06-15 09:14:24 -04002362 down_read(&tty->termios_rwsem);
2363
Joe Petersona88a69c2009-01-02 13:40:53 +00002364 /* Write out any echoed characters that are still pending */
2365 process_echoes(tty);
Alan Cox300a6202009-01-02 13:41:04 +00002366
Linus Torvalds1da177e2005-04-16 15:20:36 -07002367 add_wait_queue(&tty->write_wait, &wait);
2368 while (1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002369 if (signal_pending(current)) {
2370 retval = -ERESTARTSYS;
2371 break;
2372 }
2373 if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) {
2374 retval = -EIO;
2375 break;
2376 }
Peter Hurley582f5592013-05-17 12:49:48 -04002377 if (O_OPOST(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002378 while (nr > 0) {
Joe Petersona88a69c2009-01-02 13:40:53 +00002379 ssize_t num = process_output_block(tty, b, nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002380 if (num < 0) {
2381 if (num == -EAGAIN)
2382 break;
2383 retval = num;
2384 goto break_out;
2385 }
2386 b += num;
2387 nr -= num;
2388 if (nr == 0)
2389 break;
2390 c = *b;
Joe Petersona88a69c2009-01-02 13:40:53 +00002391 if (process_output(c, tty) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002392 break;
2393 b++; nr--;
2394 }
Alan Coxf34d7a52008-04-30 00:54:13 -07002395 if (tty->ops->flush_chars)
2396 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002397 } else {
Peter Hurley42910862014-05-03 14:04:59 +02002398 struct n_tty_data *ldata = tty->disc_data;
2399
Roman Zippeld6afe272005-07-07 17:56:55 -07002400 while (nr > 0) {
Peter Hurley42910862014-05-03 14:04:59 +02002401 mutex_lock(&ldata->output_lock);
Alan Coxf34d7a52008-04-30 00:54:13 -07002402 c = tty->ops->write(tty, b, nr);
Peter Hurley42910862014-05-03 14:04:59 +02002403 mutex_unlock(&ldata->output_lock);
Roman Zippeld6afe272005-07-07 17:56:55 -07002404 if (c < 0) {
2405 retval = c;
2406 goto break_out;
2407 }
2408 if (!c)
2409 break;
2410 b += c;
2411 nr -= c;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002412 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002413 }
2414 if (!nr)
2415 break;
2416 if (file->f_flags & O_NONBLOCK) {
2417 retval = -EAGAIN;
2418 break;
2419 }
Peter Hurley9356b532013-06-15 09:14:24 -04002420 up_read(&tty->termios_rwsem);
2421
Peter Zijlstra97d9e282014-09-24 10:18:51 +02002422 wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
Peter Hurley9356b532013-06-15 09:14:24 -04002423
2424 down_read(&tty->termios_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002425 }
2426break_out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002427 remove_wait_queue(&tty->write_wait, &wait);
Thomas Pfaffff8cb0f2009-01-02 13:47:13 +00002428 if (b - buf != nr && tty->fasync)
2429 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Peter Hurley9356b532013-06-15 09:14:24 -04002430 up_read(&tty->termios_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002431 return (b - buf) ? b - buf : retval;
2432}
2433
2434/**
Alan Cox11a96d12008-10-13 10:46:24 +01002435 * n_tty_poll - poll method for N_TTY
Linus Torvalds1da177e2005-04-16 15:20:36 -07002436 * @tty: terminal device
2437 * @file: file accessing it
2438 * @wait: poll table
2439 *
2440 * Called when the line discipline is asked to poll() for data or
2441 * for special events. This code is not serialized with respect to
2442 * other events save open/close.
2443 *
2444 * This code must be sure never to sleep through a hangup.
2445 * Called without the kernel lock held - fine
Linus Torvalds1da177e2005-04-16 15:20:36 -07002446 */
Alan Cox4edf1822008-02-08 04:18:44 -08002447
Alan Cox11a96d12008-10-13 10:46:24 +01002448static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
Alan Cox4edf1822008-02-08 04:18:44 -08002449 poll_table *wait)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002450{
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002451 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002452 unsigned int mask = 0;
2453
2454 poll_wait(file, &tty->read_wait, wait);
2455 poll_wait(file, &tty->write_wait, wait);
Peter Hurley1a486322015-04-13 13:24:34 -04002456 if (check_other_done(tty))
2457 mask |= POLLHUP;
Francesco Ruggeric4dc3042014-10-10 13:09:53 -07002458 if (input_available_p(tty, 1))
2459 mask |= POLLIN | POLLRDNORM;
Francesco Ruggeric4dc3042014-10-10 13:09:53 -07002460 if (tty->packet && tty->link->ctrl_status)
2461 mask |= POLLPRI | POLLIN | POLLRDNORM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002462 if (tty_hung_up_p(file))
2463 mask |= POLLHUP;
2464 if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) {
2465 if (MIN_CHAR(tty) && !TIME_CHAR(tty))
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002466 ldata->minimum_to_wake = MIN_CHAR(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002467 else
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002468 ldata->minimum_to_wake = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002469 }
Alan Coxf34d7a52008-04-30 00:54:13 -07002470 if (tty->ops->write && !tty_is_writelocked(tty) &&
2471 tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
2472 tty_write_room(tty) > 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002473 mask |= POLLOUT | POLLWRNORM;
2474 return mask;
2475}
2476
Jiri Slaby57c94122012-10-18 22:26:43 +02002477static unsigned long inq_canon(struct n_tty_data *ldata)
Alan Cox47afa7a2008-10-13 10:44:17 +01002478{
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002479 size_t nr, head, tail;
Alan Cox47afa7a2008-10-13 10:44:17 +01002480
Peter Hurleya73d3d62013-06-15 09:14:25 -04002481 if (ldata->canon_head == ldata->read_tail)
Alan Cox47afa7a2008-10-13 10:44:17 +01002482 return 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002483 head = ldata->canon_head;
2484 tail = ldata->read_tail;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002485 nr = head - tail;
Alan Cox47afa7a2008-10-13 10:44:17 +01002486 /* Skip EOF-chars.. */
2487 while (head != tail) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002488 if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) &&
2489 read_buf(ldata, tail) == __DISABLED_CHAR)
Alan Cox47afa7a2008-10-13 10:44:17 +01002490 nr--;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002491 tail++;
Alan Cox47afa7a2008-10-13 10:44:17 +01002492 }
2493 return nr;
2494}
2495
2496static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
2497 unsigned int cmd, unsigned long arg)
2498{
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002499 struct n_tty_data *ldata = tty->disc_data;
Alan Cox47afa7a2008-10-13 10:44:17 +01002500 int retval;
2501
2502 switch (cmd) {
2503 case TIOCOUTQ:
2504 return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
2505 case TIOCINQ:
Peter Hurley6d76bd22013-06-15 09:14:26 -04002506 down_write(&tty->termios_rwsem);
Alan Cox47afa7a2008-10-13 10:44:17 +01002507 if (L_ICANON(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02002508 retval = inq_canon(ldata);
Peter Hurley6d76bd22013-06-15 09:14:26 -04002509 else
2510 retval = read_cnt(ldata);
2511 up_write(&tty->termios_rwsem);
Alan Cox47afa7a2008-10-13 10:44:17 +01002512 return put_user(retval, (unsigned int __user *) arg);
2513 default:
2514 return n_tty_ioctl_helper(tty, file, cmd, arg);
2515 }
2516}
2517
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002518static void n_tty_fasync(struct tty_struct *tty, int on)
2519{
2520 struct n_tty_data *ldata = tty->disc_data;
2521
2522 if (!waitqueue_active(&tty->read_wait)) {
2523 if (on)
2524 ldata->minimum_to_wake = 1;
2525 else if (!tty->fasync)
2526 ldata->minimum_to_wake = N_TTY_BUF_SIZE;
2527 }
2528}
2529
Alan Coxa352def2008-07-16 21:53:12 +01002530struct tty_ldisc_ops tty_ldisc_N_TTY = {
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002531 .magic = TTY_LDISC_MAGIC,
2532 .name = "n_tty",
2533 .open = n_tty_open,
2534 .close = n_tty_close,
2535 .flush_buffer = n_tty_flush_buffer,
2536 .chars_in_buffer = n_tty_chars_in_buffer,
Alan Cox11a96d12008-10-13 10:46:24 +01002537 .read = n_tty_read,
2538 .write = n_tty_write,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002539 .ioctl = n_tty_ioctl,
2540 .set_termios = n_tty_set_termios,
Alan Cox11a96d12008-10-13 10:46:24 +01002541 .poll = n_tty_poll,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002542 .receive_buf = n_tty_receive_buf,
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002543 .write_wakeup = n_tty_write_wakeup,
2544 .fasync = n_tty_fasync,
Peter Hurley24a89d12013-06-15 09:14:15 -04002545 .receive_buf2 = n_tty_receive_buf2,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002546};
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -08002547
2548/**
2549 * n_tty_inherit_ops - inherit N_TTY methods
2550 * @ops: struct tty_ldisc_ops where to save N_TTY methods
2551 *
George Spelvin593fb1ae42013-02-12 02:00:43 -05002552 * Enables a 'subclass' line discipline to 'inherit' N_TTY
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -08002553 * methods.
2554 */
2555
2556void n_tty_inherit_ops(struct tty_ldisc_ops *ops)
2557{
2558 *ops = tty_ldisc_N_TTY;
2559 ops->owner = NULL;
2560 ops->refcount = ops->flags = 0;
2561}
2562EXPORT_SYMBOL_GPL(n_tty_inherit_ops);