blob: fb76a7d80e7e55c892254685281f924d7fe1e5f5 [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 Hurleyfb7aa032013-06-15 09:14:30 -0400116 /* consumer-published */
117 size_t read_tail;
Peter Hurley40d5e092013-06-15 10:21:17 -0400118 size_t line_start;
Peter Hurleyfb7aa032013-06-15 09:14:30 -0400119
Peter Hurleyfb7aa032013-06-15 09:14:30 -0400120 /* protected by output lock */
121 unsigned int column;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200122 unsigned int canon_column;
Peter Hurley9dfd16d2013-06-15 10:04:29 -0400123 size_t echo_tail;
Jiri Slabybddc7152012-10-18 22:26:42 +0200124
125 struct mutex atomic_read_lock;
126 struct mutex output_lock;
Jiri Slaby70ece7a2012-10-18 22:26:38 +0200127};
128
Peter Hurleyce741172013-06-15 09:14:20 -0400129static inline size_t read_cnt(struct n_tty_data *ldata)
130{
Peter Hurleya2f73be2013-06-15 09:14:22 -0400131 return ldata->read_head - ldata->read_tail;
Peter Hurleyce741172013-06-15 09:14:20 -0400132}
133
Peter Hurleybc5a5e32013-06-15 09:14:21 -0400134static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i)
135{
136 return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)];
137}
138
139static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i)
140{
141 return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)];
142}
143
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400144static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i)
145{
146 return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
147}
148
149static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i)
150{
151 return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
152}
153
Peter Hurley679e7c22015-11-27 14:11:02 -0500154static int tty_copy_to_user(struct tty_struct *tty, void __user *to,
155 size_t tail, size_t n)
Laura Abbott72586c62015-05-14 11:42:17 -0700156{
157 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley679e7c22015-11-27 14:11:02 -0500158 size_t size = N_TTY_BUF_SIZE - tail;
159 const void *from = read_buf_addr(ldata, tail);
160 int uncopied;
161
162 if (n > size) {
Peter Hurley309426a2016-01-09 22:55:27 -0800163 tty_audit_add_data(tty, from, size);
Peter Hurley679e7c22015-11-27 14:11:02 -0500164 uncopied = copy_to_user(to, from, size);
165 if (uncopied)
166 return uncopied;
167 to += size;
168 n -= size;
169 from = ldata->read_buf;
170 }
Laura Abbott72586c62015-05-14 11:42:17 -0700171
Peter Hurley309426a2016-01-09 22:55:27 -0800172 tty_audit_add_data(tty, from, n);
Laura Abbott72586c62015-05-14 11:42:17 -0700173 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{
Peter Hurley7bccc362016-01-09 21:45:12 -0800231 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
232 kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
Peter Hurleyee0bab82013-06-15 09:14:34 -0400233}
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 Hurley6d27a632016-01-10 22:40:56 -0800261 if (tty->driver->type == TTY_DRIVER_TYPE_PTY) {
Peter Hurley3afb1b392013-07-23 08:47:30 -0400262 if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
263 return;
Peter Hurley2c5dc462015-01-16 15:05:34 -0500264 n_tty_kick_worker(tty);
Peter Hurley6d27a632016-01-10 22:40:56 -0800265 tty_wakeup(tty->link);
Peter Hurley3afb1b392013-07-23 08:47:30 -0400266 return;
267 }
268
Peter Hurley6367ca72013-06-15 09:14:33 -0400269 /* If there is enough space in the read buffer now, let the
270 * low-level driver know. We use chars_in_buffer() to
271 * check the buffer, as it now knows about canonical mode.
272 * Otherwise, if the driver is throttled and the line is
273 * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
274 * we won't get any more characters.
275 */
276
277 while (1) {
278 int unthrottled;
279 tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE);
280 if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
281 break;
Peter Hurley2c5dc462015-01-16 15:05:34 -0500282 n_tty_kick_worker(tty);
Peter Hurley6367ca72013-06-15 09:14:33 -0400283 unthrottled = tty_unthrottle_safe(tty);
284 if (!unthrottled)
285 break;
286 }
287 __tty_set_flow_change(tty, 0);
288}
289
Alan Cox17b82062008-10-13 10:45:06 +0100290/**
291 * put_tty_queue - add character to tty
292 * @c: character
Jiri Slaby57c94122012-10-18 22:26:43 +0200293 * @ldata: n_tty data
Alan Cox17b82062008-10-13 10:45:06 +0100294 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400295 * Add a character to the tty read_buf queue.
296 *
297 * n_tty_receive_buf()/producer path:
298 * caller holds non-exclusive termios_rwsem
Alan Cox17b82062008-10-13 10:45:06 +0100299 */
300
Peter Hurley19e2ad62013-07-24 08:29:54 -0400301static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302{
Christian Riesch8bfbe2d2014-11-13 05:53:26 +0100303 *read_buf_addr(ldata, ldata->read_head) = c;
304 ldata->read_head++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305}
306
307/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 * reset_buffer_flags - reset buffer state
309 * @tty: terminal to reset
310 *
Peter Hurley25518c62013-03-11 16:44:31 -0400311 * Reset the read buffer counters and clear the flags.
312 * Called from n_tty_open() and n_tty_flush_buffer().
Alan Cox17b82062008-10-13 10:45:06 +0100313 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400314 * Locking: caller holds exclusive termios_rwsem
315 * (or locking is not required)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000317
Peter Hurleyb66f4fa2013-03-11 16:44:32 -0400318static void reset_buffer_flags(struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319{
Peter Hurleya73d3d62013-06-15 09:14:25 -0400320 ldata->read_head = ldata->canon_head = ldata->read_tail = 0;
Peter Hurley17bd7902013-06-15 10:04:24 -0400321 ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0;
Peter Hurley70aca712015-01-16 15:05:37 -0500322 ldata->commit_head = 0;
Peter Hurley1075a6e2013-12-09 18:06:07 -0500323 ldata->echo_mark = 0;
Peter Hurley40d5e092013-06-15 10:21:17 -0400324 ldata->line_start = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000325
Peter Hurleya73d3d62013-06-15 09:14:25 -0400326 ldata->erasing = 0;
Jiri Slaby3fe780b2012-10-18 22:26:40 +0200327 bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
Peter Hurley4d0ed182013-12-10 17:12:02 -0500328 ldata->push = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329}
330
Peter Hurleya30737a2013-03-11 16:44:22 -0400331static void n_tty_packet_mode_flush(struct tty_struct *tty)
332{
333 unsigned long flags;
334
Peter Hurleya30737a2013-03-11 16:44:22 -0400335 if (tty->link->packet) {
Peter Hurley54e8e5f2014-10-16 15:33:26 -0400336 spin_lock_irqsave(&tty->ctrl_lock, flags);
Peter Hurleya30737a2013-03-11 16:44:22 -0400337 tty->ctrl_status |= TIOCPKT_FLUSHREAD;
Peter Hurley54e8e5f2014-10-16 15:33:26 -0400338 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
Kosuke Tatsukawae81107d2015-10-02 08:27:05 +0000339 wake_up_interruptible(&tty->link->read_wait);
Peter Hurleya30737a2013-03-11 16:44:22 -0400340 }
Peter Hurleya30737a2013-03-11 16:44:22 -0400341}
342
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343/**
344 * n_tty_flush_buffer - clean input queue
345 * @tty: terminal device
346 *
Peter Hurley25518c62013-03-11 16:44:31 -0400347 * Flush the input buffer. Called when the tty layer wants the
348 * buffer flushed (eg at hangup) or when the N_TTY line discipline
349 * internally has to clean the pending queue (for example some signals).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400351 * Holds termios_rwsem to exclude producer/consumer while
352 * buffer indices are reset.
353 *
354 * Locking: ctrl_lock, exclusive termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 */
Alan Cox4edf1822008-02-08 04:18:44 -0800356
357static void n_tty_flush_buffer(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358{
Peter Hurley6d76bd22013-06-15 09:14:26 -0400359 down_write(&tty->termios_rwsem);
Peter Hurleyb66f4fa2013-03-11 16:44:32 -0400360 reset_buffer_flags(tty->disc_data);
Peter Hurley2c5dc462015-01-16 15:05:34 -0500361 n_tty_kick_worker(tty);
Alan Cox4edf1822008-02-08 04:18:44 -0800362
Peter Hurleya30737a2013-03-11 16:44:22 -0400363 if (tty->link)
364 n_tty_packet_mode_flush(tty);
Peter Hurley6d76bd22013-06-15 09:14:26 -0400365 up_write(&tty->termios_rwsem);
366}
367
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 * is_utf8_continuation - utf8 multibyte check
370 * @c: byte to check
371 *
372 * Returns true if the utf8 character 'c' is a multibyte continuation
373 * character. We use this to correctly compute the on screen size
374 * of the character when printing
375 */
Alan Cox4edf1822008-02-08 04:18:44 -0800376
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377static inline int is_utf8_continuation(unsigned char c)
378{
379 return (c & 0xc0) == 0x80;
380}
381
382/**
383 * is_continuation - multibyte check
384 * @c: byte to check
385 *
386 * Returns true if the utf8 character 'c' is a multibyte continuation
387 * character and the terminal is in unicode mode.
388 */
Alan Cox4edf1822008-02-08 04:18:44 -0800389
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390static inline int is_continuation(unsigned char c, struct tty_struct *tty)
391{
392 return I_IUTF8(tty) && is_utf8_continuation(c);
393}
394
395/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000396 * do_output_char - output one character
397 * @c: character (or partial unicode symbol)
398 * @tty: terminal device
399 * @space: space available in tty driver write buffer
400 *
401 * This is a helper function that handles one output character
402 * (including special characters like TAB, CR, LF, etc.),
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600403 * doing OPOST processing and putting the results in the
404 * tty driver's write buffer.
Joe Petersona88a69c2009-01-02 13:40:53 +0000405 *
406 * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY
407 * and NLDLY. They simply aren't relevant in the world today.
408 * If you ever need them, add them here.
409 *
410 * Returns the number of bytes of buffer space used or -1 if
411 * no space left.
412 *
413 * Locking: should be called under the output_lock to protect
414 * the column state and space left in the buffer
415 */
416
417static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
418{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200419 struct n_tty_data *ldata = tty->disc_data;
Joe Petersona88a69c2009-01-02 13:40:53 +0000420 int spaces;
421
422 if (!space)
423 return -1;
Alan Cox300a6202009-01-02 13:41:04 +0000424
Joe Petersona88a69c2009-01-02 13:40:53 +0000425 switch (c) {
426 case '\n':
427 if (O_ONLRET(tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200428 ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000429 if (O_ONLCR(tty)) {
430 if (space < 2)
431 return -1;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200432 ldata->canon_column = ldata->column = 0;
Linus Torvalds37f81fa2009-09-05 12:46:07 -0700433 tty->ops->write(tty, "\r\n", 2);
Joe Petersona88a69c2009-01-02 13:40:53 +0000434 return 2;
435 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200436 ldata->canon_column = ldata->column;
Joe Petersona88a69c2009-01-02 13:40:53 +0000437 break;
438 case '\r':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200439 if (O_ONOCR(tty) && ldata->column == 0)
Joe Petersona88a69c2009-01-02 13:40:53 +0000440 return 0;
441 if (O_OCRNL(tty)) {
442 c = '\n';
443 if (O_ONLRET(tty))
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200444 ldata->canon_column = ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000445 break;
446 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200447 ldata->canon_column = ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000448 break;
449 case '\t':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200450 spaces = 8 - (ldata->column & 7);
Joe Petersona88a69c2009-01-02 13:40:53 +0000451 if (O_TABDLY(tty) == XTABS) {
452 if (space < spaces)
453 return -1;
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200454 ldata->column += spaces;
Joe Petersona88a69c2009-01-02 13:40:53 +0000455 tty->ops->write(tty, " ", spaces);
456 return spaces;
457 }
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200458 ldata->column += spaces;
Joe Petersona88a69c2009-01-02 13:40:53 +0000459 break;
460 case '\b':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200461 if (ldata->column > 0)
462 ldata->column--;
Joe Petersona88a69c2009-01-02 13:40:53 +0000463 break;
464 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000465 if (!iscntrl(c)) {
466 if (O_OLCUC(tty))
467 c = toupper(c);
468 if (!is_continuation(c, tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200469 ldata->column++;
Joe Petersona59c0d62009-01-02 13:43:25 +0000470 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000471 break;
472 }
473
474 tty_put_char(tty, c);
475 return 1;
476}
477
478/**
479 * process_output - output post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 * @c: character (or partial unicode symbol)
481 * @tty: terminal device
482 *
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600483 * Output one character with OPOST processing.
484 * Returns -1 when the output device is full and the character
485 * must be retried.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000487 * Locking: output_lock to protect column state and space left
488 * (also, this is called from n_tty_write under the
489 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 */
Alan Cox4edf1822008-02-08 04:18:44 -0800491
Joe Petersona88a69c2009-01-02 13:40:53 +0000492static int process_output(unsigned char c, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493{
Jiri Slabybddc7152012-10-18 22:26:42 +0200494 struct n_tty_data *ldata = tty->disc_data;
Joe Petersona88a69c2009-01-02 13:40:53 +0000495 int space, retval;
496
Jiri Slabybddc7152012-10-18 22:26:42 +0200497 mutex_lock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498
Alan Coxf34d7a52008-04-30 00:54:13 -0700499 space = tty_write_room(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +0000500 retval = do_output_char(c, tty, space);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501
Jiri Slabybddc7152012-10-18 22:26:42 +0200502 mutex_unlock(&ldata->output_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000503 if (retval < 0)
504 return -1;
505 else
506 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507}
508
509/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000510 * process_output_block - block post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 * @tty: terminal device
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600512 * @buf: character buffer
513 * @nr: number of bytes to output
514 *
515 * Output a block of characters with OPOST processing.
516 * Returns the number of characters output.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 *
518 * This path is used to speed up block console writes, among other
519 * things when processing blocks of output data. It handles only
520 * the simple cases normally found and helps to generate blocks of
521 * symbols for the console driver and thus improve performance.
522 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000523 * Locking: output_lock to protect column state and space left
524 * (also, this is called from n_tty_write under the
525 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 */
Alan Cox4edf1822008-02-08 04:18:44 -0800527
Joe Petersona88a69c2009-01-02 13:40:53 +0000528static ssize_t process_output_block(struct tty_struct *tty,
529 const unsigned char *buf, unsigned int nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200531 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 int space;
Thorsten Wißmannbbd20752011-12-08 17:47:33 +0100533 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 const unsigned char *cp;
535
Jiri Slabybddc7152012-10-18 22:26:42 +0200536 mutex_lock(&ldata->output_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000537
Alan Coxf34d7a52008-04-30 00:54:13 -0700538 space = tty_write_room(tty);
Alan Cox300a6202009-01-02 13:41:04 +0000539 if (!space) {
Jiri Slabybddc7152012-10-18 22:26:42 +0200540 mutex_unlock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 return 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000542 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 if (nr > space)
544 nr = space;
545
546 for (i = 0, cp = buf; i < nr; i++, cp++) {
Joe Petersona59c0d62009-01-02 13:43:25 +0000547 unsigned char c = *cp;
548
549 switch (c) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 case '\n':
551 if (O_ONLRET(tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200552 ldata->column = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 if (O_ONLCR(tty))
554 goto break_out;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200555 ldata->canon_column = ldata->column;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 break;
557 case '\r':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200558 if (O_ONOCR(tty) && ldata->column == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 goto break_out;
560 if (O_OCRNL(tty))
561 goto break_out;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200562 ldata->canon_column = ldata->column = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 break;
564 case '\t':
565 goto break_out;
566 case '\b':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200567 if (ldata->column > 0)
568 ldata->column--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 break;
570 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000571 if (!iscntrl(c)) {
572 if (O_OLCUC(tty))
573 goto break_out;
574 if (!is_continuation(c, tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200575 ldata->column++;
Joe Petersona59c0d62009-01-02 13:43:25 +0000576 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 break;
578 }
579 }
580break_out:
Alan Coxf34d7a52008-04-30 00:54:13 -0700581 i = tty->ops->write(tty, buf, i);
Joe Petersona88a69c2009-01-02 13:40:53 +0000582
Jiri Slabybddc7152012-10-18 22:26:42 +0200583 mutex_unlock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 return i;
585}
586
Joe Petersona88a69c2009-01-02 13:40:53 +0000587/**
588 * process_echoes - write pending echo characters
589 * @tty: terminal device
590 *
591 * Write previously buffered echo (and other ldisc-generated)
592 * characters to the tty.
593 *
594 * Characters generated by the ldisc (including echoes) need to
595 * be buffered because the driver's write buffer can fill during
596 * heavy program output. Echoing straight to the driver will
597 * often fail under these conditions, causing lost characters and
598 * resulting mismatches of ldisc state information.
599 *
600 * Since the ldisc state must represent the characters actually sent
601 * to the driver at the time of the write, operations like certain
602 * changes in column state are also saved in the buffer and executed
603 * here.
604 *
605 * A circular fifo buffer is used so that the most recent characters
606 * are prioritized. Also, when control characters are echoed with a
607 * prefixed "^", the pair is treated atomically and thus not separated.
608 *
Peter Hurley019ebdf2013-06-15 10:04:25 -0400609 * Locking: callers must hold output_lock
Joe Petersona88a69c2009-01-02 13:40:53 +0000610 */
611
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400612static size_t __process_echoes(struct tty_struct *tty)
Joe Petersona88a69c2009-01-02 13:40:53 +0000613{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200614 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400615 int space, old_space;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400616 size_t tail;
Joe Petersona88a69c2009-01-02 13:40:53 +0000617 unsigned char c;
Joe Petersona88a69c2009-01-02 13:40:53 +0000618
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400619 old_space = space = tty_write_room(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +0000620
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400621 tail = ldata->echo_tail;
Peter Hurley29c7c5c2013-06-15 10:04:28 -0400622 while (ldata->echo_commit != tail) {
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400623 c = echo_buf(ldata, tail);
Joe Petersona88a69c2009-01-02 13:40:53 +0000624 if (c == ECHO_OP_START) {
625 unsigned char op;
Joe Petersona88a69c2009-01-02 13:40:53 +0000626 int no_space_left = 0;
627
628 /*
629 * If the buffer byte is the start of a multi-byte
630 * operation, get the next byte, which is either the
631 * op code or a control character value.
632 */
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400633 op = echo_buf(ldata, tail + 1);
Alan Cox300a6202009-01-02 13:41:04 +0000634
Joe Petersona88a69c2009-01-02 13:40:53 +0000635 switch (op) {
636 unsigned int num_chars, num_bs;
637
638 case ECHO_OP_ERASE_TAB:
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400639 num_chars = echo_buf(ldata, tail + 2);
Joe Petersona88a69c2009-01-02 13:40:53 +0000640
641 /*
642 * Determine how many columns to go back
643 * in order to erase the tab.
644 * This depends on the number of columns
645 * used by other characters within the tab
646 * area. If this (modulo 8) count is from
647 * the start of input rather than from a
648 * previous tab, we offset by canon column.
649 * Otherwise, tab spacing is normal.
650 */
651 if (!(num_chars & 0x80))
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200652 num_chars += ldata->canon_column;
Joe Petersona88a69c2009-01-02 13:40:53 +0000653 num_bs = 8 - (num_chars & 7);
654
655 if (num_bs > space) {
656 no_space_left = 1;
657 break;
658 }
659 space -= num_bs;
660 while (num_bs--) {
661 tty_put_char(tty, '\b');
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200662 if (ldata->column > 0)
663 ldata->column--;
Joe Petersona88a69c2009-01-02 13:40:53 +0000664 }
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400665 tail += 3;
Joe Petersona88a69c2009-01-02 13:40:53 +0000666 break;
667
668 case ECHO_OP_SET_CANON_COL:
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200669 ldata->canon_column = ldata->column;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400670 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000671 break;
672
673 case ECHO_OP_MOVE_BACK_COL:
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200674 if (ldata->column > 0)
675 ldata->column--;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400676 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000677 break;
678
679 case ECHO_OP_START:
680 /* This is an escaped echo op start code */
681 if (!space) {
682 no_space_left = 1;
683 break;
684 }
685 tty_put_char(tty, ECHO_OP_START);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200686 ldata->column++;
Joe Petersona88a69c2009-01-02 13:40:53 +0000687 space--;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400688 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000689 break;
690
691 default:
Joe Petersona88a69c2009-01-02 13:40:53 +0000692 /*
Joe Peterson62b26352009-09-09 15:03:47 -0600693 * If the op is not a special byte code,
694 * it is a ctrl char tagged to be echoed
695 * as "^X" (where X is the letter
696 * representing the control char).
697 * Note that we must ensure there is
698 * enough space for the whole ctrl pair.
699 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000700 */
Joe Peterson62b26352009-09-09 15:03:47 -0600701 if (space < 2) {
702 no_space_left = 1;
703 break;
704 }
705 tty_put_char(tty, '^');
706 tty_put_char(tty, op ^ 0100);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200707 ldata->column += 2;
Joe Peterson62b26352009-09-09 15:03:47 -0600708 space -= 2;
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400709 tail += 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000710 }
711
712 if (no_space_left)
713 break;
714 } else {
Peter Hurley582f5592013-05-17 12:49:48 -0400715 if (O_OPOST(tty)) {
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600716 int retval = do_output_char(c, tty, space);
717 if (retval < 0)
718 break;
719 space -= retval;
720 } else {
721 if (!space)
722 break;
723 tty_put_char(tty, c);
724 space -= 1;
725 }
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400726 tail += 1;
Joe Petersona88a69c2009-01-02 13:40:53 +0000727 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000728 }
729
Peter Hurleycbfd0342013-06-15 10:04:26 -0400730 /* If the echo buffer is nearly full (so that the possibility exists
731 * of echo overrun before the next commit), then discard enough
732 * data at the tail to prevent a subsequent overrun */
733 while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) {
Roel Kluinc476f652013-10-11 22:08:49 +0200734 if (echo_buf(ldata, tail) == ECHO_OP_START) {
Peter Hurley6f222532013-11-08 09:42:18 -0500735 if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB)
Peter Hurleycbfd0342013-06-15 10:04:26 -0400736 tail += 3;
737 else
738 tail += 2;
739 } else
740 tail++;
741 }
742
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400743 ldata->echo_tail = tail;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400744 return old_space - space;
Joe Petersona88a69c2009-01-02 13:40:53 +0000745}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746
Peter Hurley17bd7902013-06-15 10:04:24 -0400747static void commit_echoes(struct tty_struct *tty)
748{
749 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400750 size_t nr, old, echoed;
Peter Hurleycbfd0342013-06-15 10:04:26 -0400751 size_t head;
752
753 head = ldata->echo_head;
Peter Hurley1075a6e2013-12-09 18:06:07 -0500754 ldata->echo_mark = head;
Peter Hurleycbfd0342013-06-15 10:04:26 -0400755 old = ldata->echo_commit - ldata->echo_tail;
756
757 /* Process committed echoes if the accumulated # of bytes
758 * is over the threshold (and try again each time another
759 * block is accumulated) */
760 nr = head - ldata->echo_tail;
761 if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK))
762 return;
Peter Hurley17bd7902013-06-15 10:04:24 -0400763
Peter Hurley019ebdf2013-06-15 10:04:25 -0400764 mutex_lock(&ldata->output_lock);
Peter Hurleycbfd0342013-06-15 10:04:26 -0400765 ldata->echo_commit = head;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400766 echoed = __process_echoes(tty);
Peter Hurley019ebdf2013-06-15 10:04:25 -0400767 mutex_unlock(&ldata->output_lock);
768
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400769 if (echoed && tty->ops->flush_chars)
Peter Hurley019ebdf2013-06-15 10:04:25 -0400770 tty->ops->flush_chars(tty);
771}
772
773static void process_echoes(struct tty_struct *tty)
774{
775 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400776 size_t echoed;
Peter Hurley019ebdf2013-06-15 10:04:25 -0400777
Peter Hurleye2613be2014-02-11 16:34:55 -0500778 if (ldata->echo_mark == ldata->echo_tail)
Peter Hurley019ebdf2013-06-15 10:04:25 -0400779 return;
780
781 mutex_lock(&ldata->output_lock);
Peter Hurley1075a6e2013-12-09 18:06:07 -0500782 ldata->echo_commit = ldata->echo_mark;
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400783 echoed = __process_echoes(tty);
Peter Hurley019ebdf2013-06-15 10:04:25 -0400784 mutex_unlock(&ldata->output_lock);
785
Peter Hurleybc5b1ec2013-06-15 10:04:27 -0400786 if (echoed && tty->ops->flush_chars)
Peter Hurley019ebdf2013-06-15 10:04:25 -0400787 tty->ops->flush_chars(tty);
Peter Hurley17bd7902013-06-15 10:04:24 -0400788}
789
Peter Hurley1075a6e2013-12-09 18:06:07 -0500790/* NB: echo_mark and echo_head should be equivalent here */
Peter Hurleycbfd0342013-06-15 10:04:26 -0400791static void flush_echoes(struct tty_struct *tty)
792{
793 struct n_tty_data *ldata = tty->disc_data;
794
Peter Hurley39434ab2013-11-29 12:56:10 -0500795 if ((!L_ECHO(tty) && !L_ECHONL(tty)) ||
796 ldata->echo_commit == ldata->echo_head)
Peter Hurleycbfd0342013-06-15 10:04:26 -0400797 return;
798
799 mutex_lock(&ldata->output_lock);
800 ldata->echo_commit = ldata->echo_head;
801 __process_echoes(tty);
802 mutex_unlock(&ldata->output_lock);
803}
804
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000806 * add_echo_byte - add a byte to the echo buffer
807 * @c: unicode byte to echo
Jiri Slaby57c94122012-10-18 22:26:43 +0200808 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000809 *
810 * Add a character or operation byte to the echo buffer.
Joe Petersona88a69c2009-01-02 13:40:53 +0000811 */
812
Peter Hurleycbfd0342013-06-15 10:04:26 -0400813static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000814{
Peter Hurleyaddaebc2013-06-15 10:04:22 -0400815 *echo_buf_addr(ldata, ldata->echo_head++) = c;
Joe Petersona88a69c2009-01-02 13:40:53 +0000816}
817
818/**
819 * echo_move_back_col - add operation to move back a column
Jiri Slaby57c94122012-10-18 22:26:43 +0200820 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000821 *
822 * Add an operation to the echo buffer to move back one column.
Joe Petersona88a69c2009-01-02 13:40:53 +0000823 */
824
Jiri Slaby57c94122012-10-18 22:26:43 +0200825static void echo_move_back_col(struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000826{
Jiri Slaby57c94122012-10-18 22:26:43 +0200827 add_echo_byte(ECHO_OP_START, ldata);
828 add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000829}
830
831/**
832 * echo_set_canon_col - add operation to set the canon column
Jiri Slaby57c94122012-10-18 22:26:43 +0200833 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000834 *
835 * Add an operation to the echo buffer to set the canon column
836 * to the current column.
Joe Petersona88a69c2009-01-02 13:40:53 +0000837 */
838
Jiri Slaby57c94122012-10-18 22:26:43 +0200839static void echo_set_canon_col(struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000840{
Jiri Slaby57c94122012-10-18 22:26:43 +0200841 add_echo_byte(ECHO_OP_START, ldata);
842 add_echo_byte(ECHO_OP_SET_CANON_COL, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000843}
844
845/**
846 * echo_erase_tab - add operation to erase a tab
847 * @num_chars: number of character columns already used
848 * @after_tab: true if num_chars starts after a previous tab
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 erase a tab.
852 *
853 * Called by the eraser function, which knows how many character
854 * columns have been used since either a previous tab or the start
855 * of input. This information will be used later, along with
856 * canon column (if applicable), to go back the correct number
857 * of columns.
Joe Petersona88a69c2009-01-02 13:40:53 +0000858 */
859
860static void echo_erase_tab(unsigned int num_chars, int after_tab,
Jiri Slaby57c94122012-10-18 22:26:43 +0200861 struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000862{
Jiri Slaby57c94122012-10-18 22:26:43 +0200863 add_echo_byte(ECHO_OP_START, ldata);
864 add_echo_byte(ECHO_OP_ERASE_TAB, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000865
866 /* We only need to know this modulo 8 (tab spacing) */
867 num_chars &= 7;
868
869 /* Set the high bit as a flag if num_chars is after a previous tab */
870 if (after_tab)
871 num_chars |= 0x80;
Alan Cox300a6202009-01-02 13:41:04 +0000872
Jiri Slaby57c94122012-10-18 22:26:43 +0200873 add_echo_byte(num_chars, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000874}
875
876/**
877 * echo_char_raw - echo a character raw
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878 * @c: unicode byte to echo
879 * @tty: terminal device
880 *
Alan Cox4edf1822008-02-08 04:18:44 -0800881 * Echo user input back onto the screen. This must be called only when
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882 * L_ECHO(tty) is true. Called from the driver receive_buf path.
Alan Cox17b82062008-10-13 10:45:06 +0100883 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000884 * This variant does not treat control characters specially.
Joe Petersona88a69c2009-01-02 13:40:53 +0000885 */
886
Jiri Slaby57c94122012-10-18 22:26:43 +0200887static void echo_char_raw(unsigned char c, struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000888{
Joe Petersona88a69c2009-01-02 13:40:53 +0000889 if (c == ECHO_OP_START) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200890 add_echo_byte(ECHO_OP_START, ldata);
891 add_echo_byte(ECHO_OP_START, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000892 } else {
Jiri Slaby57c94122012-10-18 22:26:43 +0200893 add_echo_byte(c, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000894 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000895}
896
897/**
898 * echo_char - echo a character
899 * @c: unicode byte to echo
900 * @tty: terminal device
901 *
902 * Echo user input back onto the screen. This must be called only when
903 * L_ECHO(tty) is true. Called from the driver receive_buf path.
904 *
Joe Peterson62b26352009-09-09 15:03:47 -0600905 * This variant tags control characters to be echoed as "^X"
906 * (where X is the letter representing the control char).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 */
908
909static void echo_char(unsigned char c, struct tty_struct *tty)
910{
Jiri Slabybddc7152012-10-18 22:26:42 +0200911 struct n_tty_data *ldata = tty->disc_data;
912
Joe Petersona88a69c2009-01-02 13:40:53 +0000913 if (c == ECHO_OP_START) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200914 add_echo_byte(ECHO_OP_START, ldata);
915 add_echo_byte(ECHO_OP_START, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000916 } else {
Joe Peterson62b26352009-09-09 15:03:47 -0600917 if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t')
Jiri Slaby57c94122012-10-18 22:26:43 +0200918 add_echo_byte(ECHO_OP_START, ldata);
919 add_echo_byte(c, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000920 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921}
922
Alan Cox17b82062008-10-13 10:45:06 +0100923/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000924 * finish_erasing - complete erase
Jiri Slaby57c94122012-10-18 22:26:43 +0200925 * @ldata: n_tty data
Alan Cox17b82062008-10-13 10:45:06 +0100926 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000927
Jiri Slaby57c94122012-10-18 22:26:43 +0200928static inline void finish_erasing(struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200930 if (ldata->erasing) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200931 echo_char_raw('/', ldata);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200932 ldata->erasing = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 }
934}
935
936/**
937 * eraser - handle erase function
938 * @c: character input
939 * @tty: terminal device
940 *
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200941 * Perform erase and necessary output when an erase character is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 * present in the stream from the driver layer. Handles the complexities
943 * of UTF-8 multibyte symbols.
Alan Cox17b82062008-10-13 10:45:06 +0100944 *
Peter Hurley6d76bd22013-06-15 09:14:26 -0400945 * n_tty_receive_buf()/producer path:
946 * caller holds non-exclusive termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947 */
Alan Cox4edf1822008-02-08 04:18:44 -0800948
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949static void eraser(unsigned char c, struct tty_struct *tty)
950{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200951 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700952 enum { ERASE, WERASE, KILL } kill_type;
Peter Hurleybc5a5e32013-06-15 09:14:21 -0400953 size_t head;
954 size_t cnt;
955 int seen_alnums;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200957 if (ldata->read_head == ldata->canon_head) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +0000958 /* process_output('\a', tty); */ /* what do you think? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 return;
960 }
961 if (c == ERASE_CHAR(tty))
962 kill_type = ERASE;
963 else if (c == WERASE_CHAR(tty))
964 kill_type = WERASE;
965 else {
966 if (!L_ECHO(tty)) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200967 ldata->read_head = ldata->canon_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 return;
969 }
970 if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200971 ldata->read_head = ldata->canon_head;
Jiri Slaby57c94122012-10-18 22:26:43 +0200972 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973 echo_char(KILL_CHAR(tty), tty);
974 /* Add a newline if ECHOK is on and ECHOKE is off. */
975 if (L_ECHOK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +0200976 echo_char_raw('\n', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 return;
978 }
979 kill_type = KILL;
980 }
981
982 seen_alnums = 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200983 while (ldata->read_head != ldata->canon_head) {
984 head = ldata->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985
986 /* erase a single possibly multibyte character */
987 do {
Peter Hurleybc5a5e32013-06-15 09:14:21 -0400988 head--;
989 c = read_buf(ldata, head);
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200990 } while (is_continuation(c, tty) && head != ldata->canon_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991
992 /* do not partially erase */
993 if (is_continuation(c, tty))
994 break;
995
996 if (kill_type == WERASE) {
997 /* Equivalent to BSD's ALTWERASE. */
998 if (isalnum(c) || c == '_')
999 seen_alnums++;
1000 else if (seen_alnums)
1001 break;
1002 }
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001003 cnt = ldata->read_head - head;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001004 ldata->read_head = head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 if (L_ECHO(tty)) {
1006 if (L_ECHOPRT(tty)) {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001007 if (!ldata->erasing) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001008 echo_char_raw('\\', ldata);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001009 ldata->erasing = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 }
1011 /* if cnt > 1, output a multi-byte character */
1012 echo_char(c, tty);
1013 while (--cnt > 0) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001014 head++;
1015 echo_char_raw(read_buf(ldata, head), ldata);
Jiri Slaby57c94122012-10-18 22:26:43 +02001016 echo_move_back_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017 }
1018 } else if (kill_type == ERASE && !L_ECHOE(tty)) {
1019 echo_char(ERASE_CHAR(tty), tty);
1020 } else if (c == '\t') {
Joe Petersona88a69c2009-01-02 13:40:53 +00001021 unsigned int num_chars = 0;
1022 int after_tab = 0;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001023 size_t tail = ldata->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001024
Joe Petersona88a69c2009-01-02 13:40:53 +00001025 /*
1026 * Count the columns used for characters
1027 * since the start of input or after a
1028 * previous tab.
1029 * This info is used to go back the correct
1030 * number of columns.
1031 */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001032 while (tail != ldata->canon_head) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001033 tail--;
1034 c = read_buf(ldata, tail);
Joe Petersona88a69c2009-01-02 13:40:53 +00001035 if (c == '\t') {
1036 after_tab = 1;
1037 break;
Alan Cox300a6202009-01-02 13:41:04 +00001038 } else if (iscntrl(c)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039 if (L_ECHOCTL(tty))
Joe Petersona88a69c2009-01-02 13:40:53 +00001040 num_chars += 2;
1041 } else if (!is_continuation(c, tty)) {
1042 num_chars++;
1043 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001044 }
Jiri Slaby57c94122012-10-18 22:26:43 +02001045 echo_erase_tab(num_chars, after_tab, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 } else {
1047 if (iscntrl(c) && L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001048 echo_char_raw('\b', ldata);
1049 echo_char_raw(' ', ldata);
1050 echo_char_raw('\b', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051 }
1052 if (!iscntrl(c) || L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001053 echo_char_raw('\b', ldata);
1054 echo_char_raw(' ', ldata);
1055 echo_char_raw('\b', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001056 }
1057 }
1058 }
1059 if (kill_type == ERASE)
1060 break;
1061 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001062 if (ldata->read_head == ldata->canon_head && L_ECHO(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001063 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064}
1065
1066/**
1067 * isig - handle the ISIG optio
1068 * @sig: signal
1069 * @tty: terminal
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070 *
Peter Hurley8c985d12013-03-06 08:38:19 -05001071 * Called when a signal is being sent due to terminal input.
1072 * Called from the driver receive_buf path so serialized.
Alan Cox17b82062008-10-13 10:45:06 +01001073 *
Peter Hurleyd2b6f442015-01-17 15:42:06 -05001074 * Performs input and output flush if !NOFLSH. In this context, the echo
1075 * buffer is 'output'. The signal is processed first to alert any current
1076 * readers or writers to discontinue and exit their i/o loops.
1077 *
Peter Hurley8c985d12013-03-06 08:38:19 -05001078 * Locking: ctrl_lock
Linus Torvalds1da177e2005-04-16 15:20:36 -07001079 */
Alan Cox4edf1822008-02-08 04:18:44 -08001080
Peter Hurley3b19e032015-06-27 09:21:32 -04001081static void __isig(int sig, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082{
Peter Hurley8c985d12013-03-06 08:38:19 -05001083 struct pid *tty_pgrp = tty_get_pgrp(tty);
1084 if (tty_pgrp) {
1085 kill_pgrp(tty_pgrp, sig, 1);
1086 put_pid(tty_pgrp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 }
Peter Hurley3b19e032015-06-27 09:21:32 -04001088}
Peter Hurleyd2b6f442015-01-17 15:42:06 -05001089
Peter Hurley3b19e032015-06-27 09:21:32 -04001090static void isig(int sig, struct tty_struct *tty)
1091{
1092 struct n_tty_data *ldata = tty->disc_data;
1093
1094 if (L_NOFLSH(tty)) {
1095 /* signal only */
1096 __isig(sig, tty);
1097
1098 } else { /* signal and flush */
Peter Hurleyd2b6f442015-01-17 15:42:06 -05001099 up_read(&tty->termios_rwsem);
1100 down_write(&tty->termios_rwsem);
1101
Peter Hurley3b19e032015-06-27 09:21:32 -04001102 __isig(sig, tty);
1103
Peter Hurleyd2b6f442015-01-17 15:42:06 -05001104 /* clear echo buffer */
1105 mutex_lock(&ldata->output_lock);
1106 ldata->echo_head = ldata->echo_tail = 0;
1107 ldata->echo_mark = ldata->echo_commit = 0;
1108 mutex_unlock(&ldata->output_lock);
1109
1110 /* clear output buffer */
1111 tty_driver_flush_buffer(tty);
1112
1113 /* clear input buffer */
1114 reset_buffer_flags(tty->disc_data);
1115
1116 /* notify pty master of flush */
1117 if (tty->link)
1118 n_tty_packet_mode_flush(tty);
1119
1120 up_write(&tty->termios_rwsem);
1121 down_read(&tty->termios_rwsem);
1122 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123}
1124
1125/**
1126 * n_tty_receive_break - handle break
1127 * @tty: terminal
1128 *
1129 * An RS232 break event has been hit in the incoming bitstream. This
1130 * can cause a variety of events depending upon the termios settings.
1131 *
Peter Hurley6d76bd22013-06-15 09:14:26 -04001132 * n_tty_receive_buf()/producer path:
1133 * caller holds non-exclusive termios_rwsem
Peter Hurley6d76bd22013-06-15 09:14:26 -04001134 *
1135 * Note: may get exclusive termios_rwsem if flushing input buffer
Linus Torvalds1da177e2005-04-16 15:20:36 -07001136 */
Alan Cox4edf1822008-02-08 04:18:44 -08001137
Peter Hurley4b293492013-07-24 08:29:55 -04001138static void n_tty_receive_break(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139{
Jiri Slaby57c94122012-10-18 22:26:43 +02001140 struct n_tty_data *ldata = tty->disc_data;
1141
Linus Torvalds1da177e2005-04-16 15:20:36 -07001142 if (I_IGNBRK(tty))
1143 return;
1144 if (I_BRKINT(tty)) {
Peter Hurley8c985d12013-03-06 08:38:19 -05001145 isig(SIGINT, tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146 return;
1147 }
1148 if (I_PARMRK(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001149 put_tty_queue('\377', ldata);
1150 put_tty_queue('\0', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 }
Jiri Slaby57c94122012-10-18 22:26:43 +02001152 put_tty_queue('\0', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153}
1154
1155/**
1156 * n_tty_receive_overrun - handle overrun reporting
1157 * @tty: terminal
1158 *
1159 * Data arrived faster than we could process it. While the tty
1160 * driver has flagged this the bits that were missed are gone
1161 * forever.
1162 *
1163 * Called from the receive_buf path so single threaded. Does not
1164 * need locking as num_overrun and overrun_time are function
1165 * private.
1166 */
Alan Cox4edf1822008-02-08 04:18:44 -08001167
Peter Hurley4b293492013-07-24 08:29:55 -04001168static void n_tty_receive_overrun(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001170 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001172 ldata->num_overrun++;
1173 if (time_after(jiffies, ldata->overrun_time + HZ) ||
1174 time_after(ldata->overrun_time, jiffies)) {
Peter Hurley339f36b2015-11-08 13:01:13 -05001175 tty_warn(tty, "%d input overrun(s)\n", ldata->num_overrun);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001176 ldata->overrun_time = jiffies;
1177 ldata->num_overrun = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178 }
1179}
1180
1181/**
1182 * n_tty_receive_parity_error - error notifier
1183 * @tty: terminal device
1184 * @c: character
1185 *
1186 * Process a parity error and queue the right data to indicate
Peter Hurley6d76bd22013-06-15 09:14:26 -04001187 * the error case if necessary.
1188 *
1189 * n_tty_receive_buf()/producer path:
1190 * caller holds non-exclusive termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191 */
Peter Hurley4b293492013-07-24 08:29:55 -04001192static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193{
Jiri Slaby57c94122012-10-18 22:26:43 +02001194 struct n_tty_data *ldata = tty->disc_data;
1195
Peter Hurley66528f92014-06-16 08:10:42 -04001196 if (I_INPCK(tty)) {
1197 if (I_IGNPAR(tty))
1198 return;
1199 if (I_PARMRK(tty)) {
1200 put_tty_queue('\377', ldata);
1201 put_tty_queue('\0', ldata);
1202 put_tty_queue(c, ldata);
1203 } else
1204 put_tty_queue('\0', ldata);
1205 } else
Jiri Slaby57c94122012-10-18 22:26:43 +02001206 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207}
1208
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001209static void
1210n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c)
1211{
Peter Hurleyd2b6f442015-01-17 15:42:06 -05001212 isig(signal, tty);
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001213 if (I_IXON(tty))
1214 start_tty(tty);
1215 if (L_ECHO(tty)) {
1216 echo_char(c, tty);
1217 commit_echoes(tty);
Peter Hurleye2613be2014-02-11 16:34:55 -05001218 } else
1219 process_echoes(tty);
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001220 return;
1221}
1222
Linus Torvalds1da177e2005-04-16 15:20:36 -07001223/**
1224 * n_tty_receive_char - perform processing
1225 * @tty: terminal device
1226 * @c: character
1227 *
1228 * Process an individual character of input received from the driver.
Alan Cox4edf1822008-02-08 04:18:44 -08001229 * This is serialized with respect to itself by the rules for the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230 * driver above.
Peter Hurley6d76bd22013-06-15 09:14:26 -04001231 *
1232 * n_tty_receive_buf()/producer path:
1233 * caller holds non-exclusive termios_rwsem
1234 * publishes canon_head if canonical mode is active
Peter Hurleye60d27c2013-07-24 08:29:56 -04001235 *
1236 * Returns 1 if LNEXT was received, else returns 0
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237 */
1238
Peter Hurleye60d27c2013-07-24 08:29:56 -04001239static int
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001240n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001241{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001242 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244 if (I_IXON(tty)) {
1245 if (c == START_CHAR(tty)) {
1246 start_tty(tty);
Peter Hurleye2613be2014-02-11 16:34:55 -05001247 process_echoes(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001248 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249 }
1250 if (c == STOP_CHAR(tty)) {
1251 stop_tty(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001252 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 }
1254 }
Joe Peterson575537b32008-04-30 00:53:30 -07001255
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 if (L_ISIG(tty)) {
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001257 if (c == INTR_CHAR(tty)) {
1258 n_tty_receive_signal_char(tty, SIGINT, c);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001259 return 0;
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001260 } else if (c == QUIT_CHAR(tty)) {
1261 n_tty_receive_signal_char(tty, SIGQUIT, c);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001262 return 0;
Peter Hurleyb0ac50b2013-06-15 10:21:23 -04001263 } else if (c == SUSP_CHAR(tty)) {
1264 n_tty_receive_signal_char(tty, SIGTSTP, c);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001265 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001266 }
1267 }
Joe Peterson575537b32008-04-30 00:53:30 -07001268
Peter Hurley855df3c2013-07-24 08:29:50 -04001269 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
1270 start_tty(tty);
1271 process_echoes(tty);
1272 }
1273
Joe Peterson575537b32008-04-30 00:53:30 -07001274 if (c == '\r') {
1275 if (I_IGNCR(tty))
Peter Hurleye60d27c2013-07-24 08:29:56 -04001276 return 0;
Joe Peterson575537b32008-04-30 00:53:30 -07001277 if (I_ICRNL(tty))
1278 c = '\n';
1279 } else if (c == '\n' && I_INLCR(tty))
1280 c = '\r';
1281
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001282 if (ldata->icanon) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283 if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
1284 (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
1285 eraser(c, tty);
Peter Hurley17bd7902013-06-15 10:04:24 -04001286 commit_echoes(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001287 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288 }
1289 if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001290 ldata->lnext = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291 if (L_ECHO(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001292 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001293 if (L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001294 echo_char_raw('^', ldata);
1295 echo_char_raw('\b', ldata);
Peter Hurley17bd7902013-06-15 10:04:24 -04001296 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297 }
1298 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001299 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001300 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001301 if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001302 size_t tail = ldata->canon_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303
Jiri Slaby57c94122012-10-18 22:26:43 +02001304 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305 echo_char(c, tty);
Jiri Slaby57c94122012-10-18 22:26:43 +02001306 echo_char_raw('\n', ldata);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001307 while (tail != ldata->read_head) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001308 echo_char(read_buf(ldata, tail), tty);
1309 tail++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001310 }
Peter Hurley17bd7902013-06-15 10:04:24 -04001311 commit_echoes(tty);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001312 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313 }
1314 if (c == '\n') {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001315 if (L_ECHO(tty) || L_ECHONL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001316 echo_char_raw('\n', ldata);
Peter Hurley17bd7902013-06-15 10:04:24 -04001317 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 }
1319 goto handle_newline;
1320 }
1321 if (c == EOF_CHAR(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 c = __DISABLED_CHAR;
1323 goto handle_newline;
1324 }
1325 if ((c == EOL_CHAR(tty)) ||
1326 (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
1327 /*
1328 * XXX are EOL_CHAR and EOL2_CHAR echoed?!?
1329 */
1330 if (L_ECHO(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331 /* Record the column of first canon char. */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001332 if (ldata->canon_head == ldata->read_head)
Jiri Slaby57c94122012-10-18 22:26:43 +02001333 echo_set_canon_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334 echo_char(c, tty);
Peter Hurley17bd7902013-06-15 10:04:24 -04001335 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336 }
1337 /*
1338 * XXX does PARMRK doubling happen for
1339 * EOL_CHAR and EOL2_CHAR?
1340 */
Peter Hurley001ba922013-12-02 14:24:44 -05001341 if (c == (unsigned char) '\377' && I_PARMRK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001342 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343
Alan Cox4edf1822008-02-08 04:18:44 -08001344handle_newline:
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001345 set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags);
Peter Hurley6d76bd22013-06-15 09:14:26 -04001346 put_tty_queue(c, ldata);
Peter Hurley70aca712015-01-16 15:05:37 -05001347 smp_store_release(&ldata->canon_head, ldata->read_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
Kosuke Tatsukawae81107d2015-10-02 08:27:05 +00001349 wake_up_interruptible_poll(&tty->read_wait, POLLIN);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001350 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 }
1352 }
Alan Cox4edf1822008-02-08 04:18:44 -08001353
Joe Petersonacc71bb2009-01-02 13:43:32 +00001354 if (L_ECHO(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001355 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356 if (c == '\n')
Jiri Slaby57c94122012-10-18 22:26:43 +02001357 echo_char_raw('\n', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001358 else {
1359 /* Record the column of first canon char. */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001360 if (ldata->canon_head == ldata->read_head)
Jiri Slaby57c94122012-10-18 22:26:43 +02001361 echo_set_canon_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001362 echo_char(c, tty);
1363 }
Peter Hurley17bd7902013-06-15 10:04:24 -04001364 commit_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365 }
1366
Peter Hurley001ba922013-12-02 14:24:44 -05001367 /* PARMRK doubling check */
1368 if (c == (unsigned char) '\377' && I_PARMRK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001369 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370
Jiri Slaby57c94122012-10-18 22:26:43 +02001371 put_tty_queue(c, ldata);
Peter Hurleye60d27c2013-07-24 08:29:56 -04001372 return 0;
Alan Cox4edf1822008-02-08 04:18:44 -08001373}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001374
Peter Hurleye60d27c2013-07-24 08:29:56 -04001375static inline void
1376n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c)
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001377{
1378 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001379
Peter Hurleye60d27c2013-07-24 08:29:56 -04001380 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
1381 start_tty(tty);
1382 process_echoes(tty);
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001383 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001384 if (L_ECHO(tty)) {
1385 finish_erasing(ldata);
1386 /* Record the column of first canon char. */
1387 if (ldata->canon_head == ldata->read_head)
1388 echo_set_canon_col(ldata);
1389 echo_char(c, tty);
1390 commit_echoes(tty);
1391 }
Peter Hurley001ba922013-12-02 14:24:44 -05001392 /* PARMRK doubling check */
1393 if (c == (unsigned char) '\377' && I_PARMRK(tty))
Peter Hurleye60d27c2013-07-24 08:29:56 -04001394 put_tty_queue(c, ldata);
1395 put_tty_queue(c, ldata);
1396}
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001397
Peter Hurleyeb3e4662013-12-02 14:24:42 -05001398static void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
Peter Hurleye60d27c2013-07-24 08:29:56 -04001399{
1400 n_tty_receive_char_inline(tty, c);
Peter Hurley4b1f79c2013-07-24 08:29:51 -04001401}
1402
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001403static inline void
Peter Hurley7de971b2013-07-24 08:29:53 -04001404n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c)
1405{
1406 struct n_tty_data *ldata = tty->disc_data;
1407
Peter Hurleye60d27c2013-07-24 08:29:56 -04001408 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
1409 start_tty(tty);
1410 process_echoes(tty);
Peter Hurley7de971b2013-07-24 08:29:53 -04001411 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001412 if (L_ECHO(tty)) {
1413 finish_erasing(ldata);
1414 /* Record the column of first canon char. */
1415 if (ldata->canon_head == ldata->read_head)
1416 echo_set_canon_col(ldata);
1417 echo_char(c, tty);
1418 commit_echoes(tty);
1419 }
1420 put_tty_queue(c, ldata);
Peter Hurley7de971b2013-07-24 08:29:53 -04001421}
1422
Peter Hurley8dc4b252013-12-02 14:24:43 -05001423static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c)
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001424{
1425 if (I_ISTRIP(tty))
1426 c &= 0x7f;
1427 if (I_IUCLC(tty) && L_IEXTEN(tty))
1428 c = tolower(c);
1429
1430 if (I_IXON(tty)) {
1431 if (c == STOP_CHAR(tty))
1432 stop_tty(tty);
1433 else if (c == START_CHAR(tty) ||
1434 (tty->stopped && !tty->flow_stopped && I_IXANY(tty) &&
1435 c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) &&
1436 c != SUSP_CHAR(tty))) {
1437 start_tty(tty);
1438 process_echoes(tty);
1439 }
1440 }
1441}
1442
Peter Hurleyd2f8d7a2013-06-15 10:21:24 -04001443static void
1444n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag)
1445{
Peter Hurleyd2f8d7a2013-06-15 10:21:24 -04001446 switch (flag) {
1447 case TTY_BREAK:
1448 n_tty_receive_break(tty);
1449 break;
1450 case TTY_PARITY:
1451 case TTY_FRAME:
1452 n_tty_receive_parity_error(tty, c);
1453 break;
1454 case TTY_OVERRUN:
1455 n_tty_receive_overrun(tty);
1456 break;
1457 default:
Peter Hurley339f36b2015-11-08 13:01:13 -05001458 tty_err(tty, "unknown flag %d\n", flag);
Peter Hurleyd2f8d7a2013-06-15 10:21:24 -04001459 break;
1460 }
1461}
1462
Peter Hurleye60d27c2013-07-24 08:29:56 -04001463static void
1464n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag)
1465{
1466 struct n_tty_data *ldata = tty->disc_data;
1467
1468 ldata->lnext = 0;
1469 if (likely(flag == TTY_NORMAL)) {
1470 if (I_ISTRIP(tty))
1471 c &= 0x7f;
1472 if (I_IUCLC(tty) && L_IEXTEN(tty))
1473 c = tolower(c);
1474 n_tty_receive_char(tty, c);
1475 } else
1476 n_tty_receive_char_flagged(tty, c, flag);
1477}
1478
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001479static void
1480n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp,
1481 char *fp, int count)
1482{
1483 struct n_tty_data *ldata = tty->disc_data;
1484 size_t n, head;
1485
1486 head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
Peter Hurley70aca712015-01-16 15:05:37 -05001487 n = min_t(size_t, count, N_TTY_BUF_SIZE - head);
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001488 memcpy(read_buf_addr(ldata, head), cp, n);
1489 ldata->read_head += n;
1490 cp += n;
1491 count -= n;
1492
1493 head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
Peter Hurley70aca712015-01-16 15:05:37 -05001494 n = min_t(size_t, count, N_TTY_BUF_SIZE - head);
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001495 memcpy(read_buf_addr(ldata, head), cp, n);
1496 ldata->read_head += n;
1497}
1498
Peter Hurley554117b2013-06-15 10:21:25 -04001499static void
1500n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp,
1501 char *fp, int count)
1502{
1503 struct n_tty_data *ldata = tty->disc_data;
1504 char flag = TTY_NORMAL;
1505
1506 while (count--) {
1507 if (fp)
1508 flag = *fp++;
1509 if (likely(flag == TTY_NORMAL))
1510 put_tty_queue(*cp++, ldata);
1511 else
1512 n_tty_receive_char_flagged(tty, *cp++, flag);
1513 }
1514}
1515
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001516static void
1517n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp,
1518 char *fp, int count)
1519{
1520 char flag = TTY_NORMAL;
1521
1522 while (count--) {
1523 if (fp)
1524 flag = *fp++;
1525 if (likely(flag == TTY_NORMAL))
1526 n_tty_receive_char_closing(tty, *cp++);
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001527 }
1528}
1529
Peter Hurley7d88d632013-07-24 08:29:49 -04001530static void
1531n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp,
Peter Hurley6baad002013-07-24 08:29:52 -04001532 char *fp, int count)
1533{
1534 struct n_tty_data *ldata = tty->disc_data;
1535 char flag = TTY_NORMAL;
1536
1537 while (count--) {
1538 if (fp)
1539 flag = *fp++;
1540 if (likely(flag == TTY_NORMAL)) {
1541 unsigned char c = *cp++;
1542
1543 if (I_ISTRIP(tty))
1544 c &= 0x7f;
1545 if (I_IUCLC(tty) && L_IEXTEN(tty))
1546 c = tolower(c);
1547 if (L_EXTPROC(tty)) {
1548 put_tty_queue(c, ldata);
1549 continue;
1550 }
Peter Hurleye60d27c2013-07-24 08:29:56 -04001551 if (!test_bit(c, ldata->char_map))
1552 n_tty_receive_char_inline(tty, c);
1553 else if (n_tty_receive_char_special(tty, c) && count) {
1554 if (fp)
1555 flag = *fp++;
1556 n_tty_receive_char_lnext(tty, *cp++, flag);
1557 count--;
1558 }
Peter Hurley6baad002013-07-24 08:29:52 -04001559 } else
1560 n_tty_receive_char_flagged(tty, *cp++, flag);
1561 }
1562}
1563
1564static void
1565n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp,
1566 char *fp, int count)
Peter Hurley7d88d632013-07-24 08:29:49 -04001567{
Peter Hurleye60d27c2013-07-24 08:29:56 -04001568 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley7d88d632013-07-24 08:29:49 -04001569 char flag = TTY_NORMAL;
1570
1571 while (count--) {
1572 if (fp)
1573 flag = *fp++;
Peter Hurleye60d27c2013-07-24 08:29:56 -04001574 if (likely(flag == TTY_NORMAL)) {
1575 unsigned char c = *cp++;
1576
1577 if (!test_bit(c, ldata->char_map))
1578 n_tty_receive_char_fast(tty, c);
1579 else if (n_tty_receive_char_special(tty, c) && count) {
1580 if (fp)
1581 flag = *fp++;
1582 n_tty_receive_char_lnext(tty, *cp++, flag);
1583 count--;
1584 }
1585 } else
Peter Hurley7d88d632013-07-24 08:29:49 -04001586 n_tty_receive_char_flagged(tty, *cp++, flag);
1587 }
1588}
1589
Peter Hurley24a89d12013-06-15 09:14:15 -04001590static void __receive_buf(struct tty_struct *tty, const unsigned char *cp,
1591 char *fp, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001592{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001593 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleya1dd30e2013-06-15 10:21:26 -04001594 bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001595
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001596 if (ldata->real_raw)
1597 n_tty_receive_buf_real_raw(tty, cp, fp, count);
Peter Hurleya1dd30e2013-06-15 10:21:26 -04001598 else if (ldata->raw || (L_EXTPROC(tty) && !preops))
Peter Hurley554117b2013-06-15 10:21:25 -04001599 n_tty_receive_buf_raw(tty, cp, fp, count);
Peter Hurleyad0cc7b2013-06-15 10:21:27 -04001600 else if (tty->closing && !L_EXTPROC(tty))
1601 n_tty_receive_buf_closing(tty, cp, fp, count);
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001602 else {
Peter Hurleye60d27c2013-07-24 08:29:56 -04001603 if (ldata->lnext) {
1604 char flag = TTY_NORMAL;
1605
1606 if (fp)
1607 flag = *fp++;
1608 n_tty_receive_char_lnext(tty, *cp++, flag);
1609 count--;
1610 }
1611
Peter Hurley7de971b2013-07-24 08:29:53 -04001612 if (!preops && !I_PARMRK(tty))
Peter Hurley6baad002013-07-24 08:29:52 -04001613 n_tty_receive_buf_fast(tty, cp, fp, count);
1614 else
1615 n_tty_receive_buf_standard(tty, cp, fp, count);
Peter Hurleycbfd0342013-06-15 10:04:26 -04001616
1617 flush_echoes(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001618 if (tty->ops->flush_chars)
1619 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001620 }
1621
Peter Hurley70aca712015-01-16 15:05:37 -05001622 if (ldata->icanon && !L_EXTPROC(tty))
1623 return;
1624
1625 /* publish read_head to consumer */
1626 smp_store_release(&ldata->commit_head, ldata->read_head);
1627
Peter Hurley33d71362016-01-09 21:45:08 -08001628 if (read_cnt(ldata)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001629 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
Kosuke Tatsukawae81107d2015-10-02 08:27:05 +00001630 wake_up_interruptible_poll(&tty->read_wait, POLLIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001632}
1633
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001634/**
1635 * n_tty_receive_buf_common - process input
1636 * @tty: device to receive input
1637 * @cp: input chars
1638 * @fp: flags for each char (if NULL, all chars are TTY_NORMAL)
1639 * @count: number of input chars in @cp
1640 *
1641 * Called by the terminal driver when a block of characters has
1642 * been received. This function must be called from soft contexts
1643 * not from interrupt context. The driver is responsible for making
1644 * calls one at a time and in order (or using flush_to_ldisc)
1645 *
1646 * Returns the # of input chars from @cp which were processed.
1647 *
1648 * In canonical mode, the maximum line length is 4096 chars (including
1649 * the line termination char); lines longer than 4096 chars are
1650 * truncated. After 4095 chars, input data is still processed but
1651 * not stored. Overflow processing ensures the tty can always
1652 * receive more input until at least one line can be read.
1653 *
1654 * In non-canonical mode, the read buffer will only accept 4095 chars;
1655 * this provides the necessary space for a newline char if the input
1656 * mode is switched to canonical.
1657 *
1658 * Note it is possible for the read buffer to _contain_ 4096 chars
1659 * in non-canonical mode: the read buffer could already contain the
1660 * maximum canon line of 4096 chars when the mode is switched to
1661 * non-canonical.
1662 *
1663 * n_tty_receive_buf()/producer path:
1664 * claims non-exclusive termios_rwsem
1665 * publishes commit_head or canon_head
1666 */
Peter Hurley5c32d122013-12-02 14:24:41 -05001667static int
1668n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
1669 char *fp, int count, int flow)
Peter Hurley24a89d12013-06-15 09:14:15 -04001670{
1671 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001672 int room, n, rcvd = 0, overflow;
Peter Hurley24a89d12013-06-15 09:14:15 -04001673
Peter Hurley9356b532013-06-15 09:14:24 -04001674 down_read(&tty->termios_rwsem);
1675
Peter Hurley19e2ad62013-07-24 08:29:54 -04001676 while (1) {
Peter Hurley70aca712015-01-16 15:05:37 -05001677 /*
Peter Hurley06c49f92015-01-16 15:05:38 -05001678 * When PARMRK is set, each input char may take up to 3 chars
1679 * in the read buf; reduce the buffer space avail by 3x
Peter Hurley70aca712015-01-16 15:05:37 -05001680 *
1681 * If we are doing input canonicalization, and there are no
1682 * pending newlines, let characters through without limit, so
1683 * that erase characters will be handled. Other excess
1684 * characters will be beeped.
1685 *
1686 * paired with store in *_copy_from_read_buf() -- guarantees
1687 * the consumer has loaded the data in read_buf up to the new
1688 * read_tail (so this producer will not overwrite unread data)
1689 */
1690 size_t tail = smp_load_acquire(&ldata->read_tail);
Peter Hurley70aca712015-01-16 15:05:37 -05001691
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001692 room = N_TTY_BUF_SIZE - (ldata->read_head - tail);
Peter Hurley70aca712015-01-16 15:05:37 -05001693 if (I_PARMRK(tty))
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001694 room = (room + 2) / 3;
1695 room--;
1696 if (room <= 0) {
1697 overflow = ldata->icanon && ldata->canon_head == tail;
1698 if (overflow && room < 0)
1699 ldata->read_head--;
1700 room = overflow;
1701 ldata->no_room = flow && !room;
1702 } else
1703 overflow = 0;
Peter Hurley70aca712015-01-16 15:05:37 -05001704
Peter Hurley19e2ad62013-07-24 08:29:54 -04001705 n = min(count, room);
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001706 if (!n)
Peter Hurley19e2ad62013-07-24 08:29:54 -04001707 break;
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001708
1709 /* ignore parity errors if handling overflow */
1710 if (!overflow || !fp || *fp != TTY_PARITY)
1711 __receive_buf(tty, cp, fp, n);
1712
Peter Hurley19e2ad62013-07-24 08:29:54 -04001713 cp += n;
1714 if (fp)
1715 fp += n;
1716 count -= n;
1717 rcvd += n;
Peter Hurley4a23a4d2013-06-15 10:21:22 -04001718 }
Peter Hurley24a89d12013-06-15 09:14:15 -04001719
Peter Hurley19e2ad62013-07-24 08:29:54 -04001720 tty->receive_room = room;
Peter Hurleyfb5ef9e2015-01-16 15:05:39 -05001721
1722 /* Unthrottle if handling overflow on pty */
1723 if (tty->driver->type == TTY_DRIVER_TYPE_PTY) {
1724 if (overflow) {
1725 tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE);
1726 tty_unthrottle_safe(tty);
1727 __tty_set_flow_change(tty, 0);
1728 }
1729 } else
1730 n_tty_check_throttle(tty);
1731
Peter Hurley9356b532013-06-15 09:14:24 -04001732 up_read(&tty->termios_rwsem);
1733
Peter Hurley19e2ad62013-07-24 08:29:54 -04001734 return rcvd;
Peter Hurley24a89d12013-06-15 09:14:15 -04001735}
1736
Peter Hurley5c32d122013-12-02 14:24:41 -05001737static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1738 char *fp, int count)
1739{
1740 n_tty_receive_buf_common(tty, cp, fp, count, 0);
1741}
1742
1743static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp,
1744 char *fp, int count)
1745{
1746 return n_tty_receive_buf_common(tty, cp, fp, count, 1);
1747}
1748
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749/**
1750 * n_tty_set_termios - termios data changed
1751 * @tty: terminal
1752 * @old: previous data
1753 *
1754 * Called by the tty layer when the user changes termios flags so
1755 * that the line discipline can plan ahead. This function cannot sleep
Alan Cox4edf1822008-02-08 04:18:44 -08001756 * and is protected from re-entry by the tty layer. The user is
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757 * guaranteed that this function will not be re-entered or in progress
1758 * when the ldisc is closed.
Alan Cox17b82062008-10-13 10:45:06 +01001759 *
Peter Hurley6a1c0682013-06-15 09:14:23 -04001760 * Locking: Caller holds tty->termios_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761 */
Alan Cox4edf1822008-02-08 04:18:44 -08001762
1763static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001764{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001765 struct n_tty_data *ldata = tty->disc_data;
Alan Cox47afa7a2008-10-13 10:44:17 +01001766
Peter Hurleyc786f742013-09-17 12:53:35 -04001767 if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) {
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001768 bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
Peter Hurley4d0ed182013-12-10 17:12:02 -05001769 ldata->line_start = ldata->read_tail;
1770 if (!L_ICANON(tty) || !read_cnt(ldata)) {
1771 ldata->canon_head = ldata->read_tail;
1772 ldata->push = 0;
1773 } else {
1774 set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1),
1775 ldata->read_flags);
1776 ldata->canon_head = ldata->read_head;
1777 ldata->push = 1;
1778 }
Peter Hurley70aca712015-01-16 15:05:37 -05001779 ldata->commit_head = ldata->read_head;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001780 ldata->erasing = 0;
Peter Hurley6f9b0282013-06-15 09:14:27 -04001781 ldata->lnext = 0;
Alan Cox47afa7a2008-10-13 10:44:17 +01001782 }
1783
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001784 ldata->icanon = (L_ICANON(tty) != 0);
Peter Hurley582f5592013-05-17 12:49:48 -04001785
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786 if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
1787 I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
1788 I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
1789 I_PARMRK(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001790 bitmap_zero(ldata->char_map, 256);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791
1792 if (I_IGNCR(tty) || I_ICRNL(tty))
Peter Hurley1bb9d562013-06-15 10:21:20 -04001793 set_bit('\r', ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001794 if (I_INLCR(tty))
Peter Hurley1bb9d562013-06-15 10:21:20 -04001795 set_bit('\n', ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001796
1797 if (L_ICANON(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001798 set_bit(ERASE_CHAR(tty), ldata->char_map);
1799 set_bit(KILL_CHAR(tty), ldata->char_map);
1800 set_bit(EOF_CHAR(tty), ldata->char_map);
1801 set_bit('\n', ldata->char_map);
1802 set_bit(EOL_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001803 if (L_IEXTEN(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001804 set_bit(WERASE_CHAR(tty), ldata->char_map);
1805 set_bit(LNEXT_CHAR(tty), ldata->char_map);
1806 set_bit(EOL2_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807 if (L_ECHO(tty))
1808 set_bit(REPRINT_CHAR(tty),
Peter Hurley1bb9d562013-06-15 10:21:20 -04001809 ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810 }
1811 }
1812 if (I_IXON(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001813 set_bit(START_CHAR(tty), ldata->char_map);
1814 set_bit(STOP_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001815 }
1816 if (L_ISIG(tty)) {
Peter Hurley1bb9d562013-06-15 10:21:20 -04001817 set_bit(INTR_CHAR(tty), ldata->char_map);
1818 set_bit(QUIT_CHAR(tty), ldata->char_map);
1819 set_bit(SUSP_CHAR(tty), ldata->char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820 }
Peter Hurley1bb9d562013-06-15 10:21:20 -04001821 clear_bit(__DISABLED_CHAR, ldata->char_map);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001822 ldata->raw = 0;
1823 ldata->real_raw = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824 } else {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001825 ldata->raw = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826 if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
1827 (I_IGNPAR(tty) || !I_INPCK(tty)) &&
1828 (tty->driver->flags & TTY_DRIVER_REAL_RAW))
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001829 ldata->real_raw = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001830 else
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001831 ldata->real_raw = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001832 }
Wang YanQingdab73b42013-05-09 14:16:47 +08001833 /*
1834 * Fix tty hang when I_IXON(tty) is cleared, but the tty
1835 * been stopped by STOP_CHAR(tty) before it.
1836 */
Peter Hurleye2613be2014-02-11 16:34:55 -05001837 if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) {
Wang YanQingdab73b42013-05-09 14:16:47 +08001838 start_tty(tty);
Peter Hurleye2613be2014-02-11 16:34:55 -05001839 process_echoes(tty);
1840 }
Wang YanQingdab73b42013-05-09 14:16:47 +08001841
Alan Coxf34d7a52008-04-30 00:54:13 -07001842 /* The termios change make the tty ready for I/O */
Kosuke Tatsukawae81107d2015-10-02 08:27:05 +00001843 wake_up_interruptible(&tty->write_wait);
1844 wake_up_interruptible(&tty->read_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845}
1846
1847/**
1848 * n_tty_close - close the ldisc for this tty
1849 * @tty: device
1850 *
Alan Cox4edf1822008-02-08 04:18:44 -08001851 * Called from the terminal layer when this line discipline is
1852 * being shut down, either because of a close or becsuse of a
Linus Torvalds1da177e2005-04-16 15:20:36 -07001853 * discipline change. The function will not be called while other
1854 * ldisc methods are in progress.
1855 */
Alan Cox4edf1822008-02-08 04:18:44 -08001856
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857static void n_tty_close(struct tty_struct *tty)
1858{
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001859 struct n_tty_data *ldata = tty->disc_data;
1860
Peter Hurley79901312013-03-11 16:44:23 -04001861 if (tty->link)
1862 n_tty_packet_mode_flush(tty);
1863
Peter Hurley20bafb32013-06-15 10:21:19 -04001864 vfree(ldata);
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001865 tty->disc_data = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866}
1867
1868/**
1869 * n_tty_open - open an ldisc
1870 * @tty: terminal to open
1871 *
Alan Cox4edf1822008-02-08 04:18:44 -08001872 * Called when this line discipline is being attached to the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001873 * terminal device. Can sleep. Called serialized so that no
1874 * other events will occur in parallel. No further open will occur
1875 * until a close.
1876 */
1877
1878static int n_tty_open(struct tty_struct *tty)
1879{
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001880 struct n_tty_data *ldata;
1881
Peter Hurley20bafb32013-06-15 10:21:19 -04001882 /* Currently a malloc failure here can panic */
1883 ldata = vmalloc(sizeof(*ldata));
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001884 if (!ldata)
1885 goto err;
1886
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001887 ldata->overrun_time = jiffies;
Jiri Slabybddc7152012-10-18 22:26:42 +02001888 mutex_init(&ldata->atomic_read_lock);
1889 mutex_init(&ldata->output_lock);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001890
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001891 tty->disc_data = ldata;
Peter Hurleyb66f4fa2013-03-11 16:44:32 -04001892 reset_buffer_flags(tty->disc_data);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001893 ldata->column = 0;
Peter Hurley20bafb32013-06-15 10:21:19 -04001894 ldata->canon_column = 0;
Peter Hurley20bafb32013-06-15 10:21:19 -04001895 ldata->num_overrun = 0;
1896 ldata->no_room = 0;
1897 ldata->lnext = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898 tty->closing = 0;
Peter Hurleyb66f4fa2013-03-11 16:44:32 -04001899 /* indicate buffer work may resume */
1900 clear_bit(TTY_LDISC_HALTED, &tty->flags);
1901 n_tty_set_termios(tty, NULL);
1902 tty_unthrottle(tty);
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001903
Linus Torvalds1da177e2005-04-16 15:20:36 -07001904 return 0;
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001905err:
Jiri Slabyb91939f2012-10-18 22:26:35 +02001906 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001907}
1908
Peter Hurleyeafbe672013-12-02 14:24:45 -05001909static inline int input_available_p(struct tty_struct *tty, int poll)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001910{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001911 struct n_tty_data *ldata = tty->disc_data;
Peter Hurleya5934802014-02-11 11:49:58 -05001912 int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001913
Peter Hurley25e8d0e2014-02-11 18:55:30 -05001914 if (ldata->icanon && !L_EXTPROC(tty))
1915 return ldata->canon_head != ldata->read_tail;
1916 else
Peter Hurley70aca712015-01-16 15:05:37 -05001917 return ldata->commit_head - ldata->read_tail >= amt;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001918}
1919
Peter Hurley1a486322015-04-13 13:24:34 -04001920static inline int check_other_done(struct tty_struct *tty)
1921{
1922 int done = test_bit(TTY_OTHER_DONE, &tty->flags);
1923 if (done) {
1924 /* paired with cmpxchg() in check_other_closed(); ensures
1925 * read buffer head index is not stale
1926 */
1927 smp_mb__after_atomic();
1928 }
1929 return done;
1930}
1931
Linus Torvalds1da177e2005-04-16 15:20:36 -07001932/**
Thorsten Wißmannbbd20752011-12-08 17:47:33 +01001933 * copy_from_read_buf - copy read data directly
Linus Torvalds1da177e2005-04-16 15:20:36 -07001934 * @tty: terminal device
1935 * @b: user data
1936 * @nr: size of data
1937 *
Alan Cox11a96d12008-10-13 10:46:24 +01001938 * Helper function to speed up n_tty_read. It is only called when
Linus Torvalds1da177e2005-04-16 15:20:36 -07001939 * ICANON is off; it copies characters straight from the tty queue to
1940 * user space directly. It can be profitably called twice; once to
1941 * drain the space from the tail pointer to the (physical) end of the
1942 * buffer, and once to drain the space from the (physical) beginning of
1943 * the buffer to head pointer.
1944 *
Jiri Slabybddc7152012-10-18 22:26:42 +02001945 * Called under the ldata->atomic_read_lock sem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001946 *
Peter Hurley6d76bd22013-06-15 09:14:26 -04001947 * n_tty_read()/consumer path:
1948 * caller holds non-exclusive termios_rwsem
1949 * read_tail published
Linus Torvalds1da177e2005-04-16 15:20:36 -07001950 */
Alan Cox4edf1822008-02-08 04:18:44 -08001951
Alan Cox33f0f882006-01-09 20:54:13 -08001952static int copy_from_read_buf(struct tty_struct *tty,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001953 unsigned char __user **b,
1954 size_t *nr)
1955
1956{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001957 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958 int retval;
1959 size_t n;
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02001960 bool is_eof;
Peter Hurley70aca712015-01-16 15:05:37 -05001961 size_t head = smp_load_acquire(&ldata->commit_head);
Peter Hurleybc5a5e32013-06-15 09:14:21 -04001962 size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001963
1964 retval = 0;
Peter Hurley70aca712015-01-16 15:05:37 -05001965 n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001966 n = min(*nr, n);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001967 if (n) {
Peter Hurleye661cf72015-11-27 14:11:03 -05001968 const unsigned char *from = read_buf_addr(ldata, tail);
1969 retval = copy_to_user(*b, from, n);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001970 n -= retval;
Peter Hurleye661cf72015-11-27 14:11:03 -05001971 is_eof = n == 1 && *from == EOF_CHAR(tty);
Peter Hurley309426a2016-01-09 22:55:27 -08001972 tty_audit_add_data(tty, from, n);
Peter Hurley70aca712015-01-16 15:05:37 -05001973 smp_store_release(&ldata->read_tail, ldata->read_tail + n);
hyc@symas.com26df6d12010-06-22 10:14:49 -07001974 /* Turn single EOF into zero-length read */
Peter Hurley70aca712015-01-16 15:05:37 -05001975 if (L_EXTPROC(tty) && ldata->icanon && is_eof &&
1976 (head == ldata->read_tail))
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02001977 n = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978 *b += n;
1979 *nr -= n;
1980 }
1981 return retval;
1982}
1983
Peter Hurley88bb0de2013-06-15 09:14:16 -04001984/**
Peter Hurley32f13522013-06-15 09:14:17 -04001985 * canon_copy_from_read_buf - copy read data in canonical mode
Peter Hurley88bb0de2013-06-15 09:14:16 -04001986 * @tty: terminal device
1987 * @b: user data
1988 * @nr: size of data
1989 *
1990 * Helper function for n_tty_read. It is only called when ICANON is on;
Peter Hurley32f13522013-06-15 09:14:17 -04001991 * it copies one line of input up to and including the line-delimiting
1992 * character into the user-space buffer.
Peter Hurley88bb0de2013-06-15 09:14:16 -04001993 *
Peter Hurley4d0ed182013-12-10 17:12:02 -05001994 * NB: When termios is changed from non-canonical to canonical mode and
1995 * the read buffer contains data, n_tty_set_termios() simulates an EOF
1996 * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer.
1997 * This causes data already processed as input to be immediately available
1998 * as input although a newline has not been received.
1999 *
Peter Hurley88bb0de2013-06-15 09:14:16 -04002000 * Called under the atomic_read_lock mutex
Peter Hurley6d76bd22013-06-15 09:14:26 -04002001 *
2002 * n_tty_read()/consumer path:
2003 * caller holds non-exclusive termios_rwsem
2004 * read_tail published
Peter Hurley88bb0de2013-06-15 09:14:16 -04002005 */
2006
Peter Hurley32f13522013-06-15 09:14:17 -04002007static int canon_copy_from_read_buf(struct tty_struct *tty,
2008 unsigned char __user **b,
2009 size_t *nr)
Peter Hurley88bb0de2013-06-15 09:14:16 -04002010{
2011 struct n_tty_data *ldata = tty->disc_data;
Peter Hurley32f13522013-06-15 09:14:17 -04002012 size_t n, size, more, c;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002013 size_t eol;
2014 size_t tail;
2015 int ret, found = 0;
Peter Hurley88bb0de2013-06-15 09:14:16 -04002016
2017 /* N.B. avoid overrun if nr == 0 */
Peter Hurleyac8f3bf2015-11-27 13:59:20 -05002018 if (!*nr)
Peter Hurley32f13522013-06-15 09:14:17 -04002019 return 0;
Peter Hurley88bb0de2013-06-15 09:14:16 -04002020
Peter Hurleyac8f3bf2015-11-27 13:59:20 -05002021 n = min(*nr + 1, smp_load_acquire(&ldata->canon_head) - ldata->read_tail);
2022
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002023 tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
Peter Hurley32f13522013-06-15 09:14:17 -04002024 size = min_t(size_t, tail + n, N_TTY_BUF_SIZE);
2025
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002026 n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n",
Peter Hurley32f13522013-06-15 09:14:17 -04002027 __func__, *nr, tail, n, size);
2028
2029 eol = find_next_bit(ldata->read_flags, size, tail);
2030 more = n - (size - tail);
2031 if (eol == N_TTY_BUF_SIZE && more) {
2032 /* scan wrapped without finding set bit */
2033 eol = find_next_bit(ldata->read_flags, more, 0);
Peter Hurleyb985e9e2015-11-27 14:11:04 -05002034 found = eol != more;
2035 } else
2036 found = eol != size;
Peter Hurley32f13522013-06-15 09:14:17 -04002037
Peter Hurleyc77569d2013-11-22 07:16:25 -05002038 n = eol - tail;
Mark Tomlinsonda555db2015-05-18 12:01:48 +12002039 if (n > N_TTY_BUF_SIZE)
2040 n += N_TTY_BUF_SIZE;
Peter Hurleyac8f3bf2015-11-27 13:59:20 -05002041 c = n + found;
Peter Hurley32f13522013-06-15 09:14:17 -04002042
Peter Hurleyac8f3bf2015-11-27 13:59:20 -05002043 if (!found || read_buf(ldata, eol) != __DISABLED_CHAR) {
2044 c = min(*nr, c);
2045 n = c;
Peter Hurley40d5e092013-06-15 10:21:17 -04002046 }
Peter Hurley32f13522013-06-15 09:14:17 -04002047
Peter Hurley679e7c22015-11-27 14:11:02 -05002048 n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu tail:%zu more:%zu\n",
2049 __func__, eol, found, n, c, tail, more);
Peter Hurley32f13522013-06-15 09:14:17 -04002050
Peter Hurley679e7c22015-11-27 14:11:02 -05002051 ret = tty_copy_to_user(tty, *b, tail, n);
Peter Hurley32f13522013-06-15 09:14:17 -04002052 if (ret)
2053 return -EFAULT;
2054 *b += n;
2055 *nr -= n;
2056
Peter Hurleya73d3d62013-06-15 09:14:25 -04002057 if (found)
Peter Hurley6d76bd22013-06-15 09:14:26 -04002058 clear_bit(eol, ldata->read_flags);
Peter Hurley70aca712015-01-16 15:05:37 -05002059 smp_store_release(&ldata->read_tail, ldata->read_tail + c);
Peter Hurley88bb0de2013-06-15 09:14:16 -04002060
Peter Hurley40d5e092013-06-15 10:21:17 -04002061 if (found) {
Peter Hurley4d0ed182013-12-10 17:12:02 -05002062 if (!ldata->push)
2063 ldata->line_start = ldata->read_tail;
2064 else
2065 ldata->push = 0;
Peter Hurleyb50819f2016-01-09 22:55:30 -08002066 tty_audit_push();
Peter Hurley40d5e092013-06-15 10:21:17 -04002067 }
Peter Hurleyac8f3bf2015-11-27 13:59:20 -05002068 return 0;
Peter Hurley88bb0de2013-06-15 09:14:16 -04002069}
2070
Al Virocc4191d2008-03-29 03:08:48 +00002071extern ssize_t redirected_tty_write(struct file *, const char __user *,
Alan Cox4edf1822008-02-08 04:18:44 -08002072 size_t, loff_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002073
2074/**
2075 * job_control - check job control
2076 * @tty: tty
2077 * @file: file handle
2078 *
2079 * Perform job control management checks on this file/tty descriptor
Alan Cox4edf1822008-02-08 04:18:44 -08002080 * and if appropriate send any needed signals and return a negative
Linus Torvalds1da177e2005-04-16 15:20:36 -07002081 * error code if action should be taken.
Alan Cox04f378b2008-04-30 00:53:29 -07002082 *
Peter Hurley01a5e442013-03-06 08:38:20 -05002083 * Locking: redirected write test is safe
2084 * current->signal->tty check is safe
2085 * ctrl_lock to safely reference tty->pgrp
Linus Torvalds1da177e2005-04-16 15:20:36 -07002086 */
Alan Cox4edf1822008-02-08 04:18:44 -08002087
Linus Torvalds1da177e2005-04-16 15:20:36 -07002088static int job_control(struct tty_struct *tty, struct file *file)
2089{
2090 /* Job control check -- must be done at start and after
2091 every sleep (POSIX.1 7.1.1.4). */
2092 /* NOTE: not yet done after every sleep pending a thorough
2093 check of the logic of this change. -- jlc */
2094 /* don't stop on /dev/console */
Peter Hurley2812d9e2015-10-10 20:28:42 -04002095 if (file->f_op->write == redirected_tty_write)
Peter Hurley01a5e442013-03-06 08:38:20 -05002096 return 0;
2097
Peter Hurley2812d9e2015-10-10 20:28:42 -04002098 return __tty_check_change(tty, SIGTTIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002099}
Alan Cox4edf1822008-02-08 04:18:44 -08002100
Linus Torvalds1da177e2005-04-16 15:20:36 -07002101
2102/**
Alan Cox11a96d12008-10-13 10:46:24 +01002103 * n_tty_read - read function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07002104 * @tty: tty device
2105 * @file: file object
2106 * @buf: userspace buffer pointer
2107 * @nr: size of I/O
2108 *
2109 * Perform reads for the line discipline. We are guaranteed that the
2110 * line discipline will not be closed under us but we may get multiple
2111 * parallel readers and must handle this ourselves. We may also get
2112 * a hangup. Always called in user context, may sleep.
2113 *
2114 * This code must be sure never to sleep through a hangup.
Peter Hurley6d76bd22013-06-15 09:14:26 -04002115 *
2116 * n_tty_read()/consumer path:
2117 * claims non-exclusive termios_rwsem
2118 * publishes read_tail
Linus Torvalds1da177e2005-04-16 15:20:36 -07002119 */
Alan Cox4edf1822008-02-08 04:18:44 -08002120
Alan Cox11a96d12008-10-13 10:46:24 +01002121static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002122 unsigned char __user *buf, size_t nr)
2123{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002124 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125 unsigned char __user *b = buf;
Peter Zijlstra97d9e282014-09-24 10:18:51 +02002126 DEFINE_WAIT_FUNC(wait, woken_wake_function);
Peter Hurley1a486322015-04-13 13:24:34 -04002127 int c, done;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002128 int minimum, time;
2129 ssize_t retval = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002130 long timeout;
Alan Cox04f378b2008-04-30 00:53:29 -07002131 int packet;
Peter Hurley2c5dc462015-01-16 15:05:34 -05002132 size_t tail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002133
Linus Torvalds1da177e2005-04-16 15:20:36 -07002134 c = job_control(tty, file);
Alan Cox4edf1822008-02-08 04:18:44 -08002135 if (c < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002136 return c;
Alan Cox4edf1822008-02-08 04:18:44 -08002137
Peter Hurleyaefceaf2013-08-11 08:04:23 -04002138 /*
2139 * Internal serialization of reads.
2140 */
2141 if (file->f_flags & O_NONBLOCK) {
2142 if (!mutex_trylock(&ldata->atomic_read_lock))
2143 return -EAGAIN;
2144 } else {
2145 if (mutex_lock_interruptible(&ldata->atomic_read_lock))
2146 return -ERESTARTSYS;
2147 }
2148
Peter Hurley9356b532013-06-15 09:14:24 -04002149 down_read(&tty->termios_rwsem);
2150
Linus Torvalds1da177e2005-04-16 15:20:36 -07002151 minimum = time = 0;
2152 timeout = MAX_SCHEDULE_TIMEOUT;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002153 if (!ldata->icanon) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002154 minimum = MIN_CHAR(tty);
2155 if (minimum) {
Peter Hurleya6e54312013-06-15 07:28:29 -04002156 time = (HZ / 10) * TIME_CHAR(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002157 } else {
Peter Hurleya6e54312013-06-15 07:28:29 -04002158 timeout = (HZ / 10) * TIME_CHAR(tty);
Peter Hurley33d71362016-01-09 21:45:08 -08002159 minimum = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002160 }
2161 }
2162
Alan Cox04f378b2008-04-30 00:53:29 -07002163 packet = tty->packet;
Peter Hurley2c5dc462015-01-16 15:05:34 -05002164 tail = ldata->read_tail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002165
2166 add_wait_queue(&tty->read_wait, &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002167 while (nr) {
2168 /* First test for status change. */
Alan Cox04f378b2008-04-30 00:53:29 -07002169 if (packet && tty->link->ctrl_status) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002170 unsigned char cs;
2171 if (b != buf)
2172 break;
Peter Hurley6054c16e2014-10-16 15:33:25 -04002173 spin_lock_irq(&tty->link->ctrl_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002174 cs = tty->link->ctrl_status;
2175 tty->link->ctrl_status = 0;
Peter Hurley6054c16e2014-10-16 15:33:25 -04002176 spin_unlock_irq(&tty->link->ctrl_lock);
Peter Hurleyeab25a52016-01-09 22:55:26 -08002177 if (put_user(cs, b)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002178 retval = -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002179 break;
2180 }
Peter Hurleyeab25a52016-01-09 22:55:26 -08002181 b++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002182 nr--;
2183 break;
2184 }
Alan Cox4edf1822008-02-08 04:18:44 -08002185
Peter Hurley1a486322015-04-13 13:24:34 -04002186 done = check_other_done(tty);
2187
Linus Torvalds1da177e2005-04-16 15:20:36 -07002188 if (!input_available_p(tty, 0)) {
Peter Hurley1a486322015-04-13 13:24:34 -04002189 if (done) {
Peter Hurley52bce7f2014-11-05 12:13:05 -05002190 retval = -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002191 break;
2192 }
Peter Hurley52bce7f2014-11-05 12:13:05 -05002193 if (tty_hung_up_p(file))
2194 break;
2195 if (!timeout)
2196 break;
2197 if (file->f_flags & O_NONBLOCK) {
2198 retval = -EAGAIN;
2199 break;
2200 }
2201 if (signal_pending(current)) {
2202 retval = -ERESTARTSYS;
2203 break;
2204 }
Peter Hurley52bce7f2014-11-05 12:13:05 -05002205 up_read(&tty->termios_rwsem);
2206
Linus Torvalds37da7bb2014-12-14 15:23:32 -08002207 timeout = wait_woken(&wait, TASK_INTERRUPTIBLE,
2208 timeout);
Peter Hurley52bce7f2014-11-05 12:13:05 -05002209
2210 down_read(&tty->termios_rwsem);
2211 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002212 }
2213
Jiri Slaby53c5ee22012-10-18 22:26:39 +02002214 if (ldata->icanon && !L_EXTPROC(tty)) {
Peter Hurley32f13522013-06-15 09:14:17 -04002215 retval = canon_copy_from_read_buf(tty, &b, &nr);
Peter Hurleyac8f3bf2015-11-27 13:59:20 -05002216 if (retval)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002217 break;
2218 } else {
2219 int uncopied;
Peter Hurley95ea90d2014-10-16 15:33:30 -04002220
2221 /* Deal with packet mode. */
2222 if (packet && b == buf) {
Peter Hurleyeab25a52016-01-09 22:55:26 -08002223 if (put_user(TIOCPKT_DATA, b)) {
Peter Hurley95ea90d2014-10-16 15:33:30 -04002224 retval = -EFAULT;
Peter Hurley95ea90d2014-10-16 15:33:30 -04002225 break;
2226 }
Peter Hurleyeab25a52016-01-09 22:55:26 -08002227 b++;
Peter Hurley95ea90d2014-10-16 15:33:30 -04002228 nr--;
2229 }
2230
Linus Torvalds1da177e2005-04-16 15:20:36 -07002231 uncopied = copy_from_read_buf(tty, &b, &nr);
2232 uncopied += copy_from_read_buf(tty, &b, &nr);
2233 if (uncopied) {
2234 retval = -EFAULT;
2235 break;
2236 }
2237 }
2238
Peter Hurley6367ca72013-06-15 09:14:33 -04002239 n_tty_check_unthrottle(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002240
2241 if (b - buf >= minimum)
2242 break;
2243 if (time)
2244 timeout = time;
2245 }
Peter Hurley2c5dc462015-01-16 15:05:34 -05002246 if (tail != ldata->read_tail)
2247 n_tty_kick_worker(tty);
Peter Hurley42458f42013-11-07 13:59:46 -05002248 up_read(&tty->termios_rwsem);
2249
Linus Torvalds1da177e2005-04-16 15:20:36 -07002250 remove_wait_queue(&tty->read_wait, &wait);
Peter Hurleyaebf04532013-11-07 14:01:57 -05002251 mutex_unlock(&ldata->atomic_read_lock);
2252
Peter Hurley40d5e092013-06-15 10:21:17 -04002253 if (b - buf)
2254 retval = b - buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002255
2256 return retval;
2257}
2258
2259/**
Alan Cox11a96d12008-10-13 10:46:24 +01002260 * n_tty_write - write function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07002261 * @tty: tty device
2262 * @file: file object
2263 * @buf: userspace buffer pointer
2264 * @nr: size of I/O
2265 *
Joe Petersona88a69c2009-01-02 13:40:53 +00002266 * Write function of the terminal device. This is serialized with
Linus Torvalds1da177e2005-04-16 15:20:36 -07002267 * respect to other write callers but not to termios changes, reads
Joe Petersona88a69c2009-01-02 13:40:53 +00002268 * and other such events. Since the receive code will echo characters,
2269 * thus calling driver write methods, the output_lock is used in
2270 * the output processing functions called here as well as in the
2271 * echo processing function to protect the column state and space
2272 * left in the buffer.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002273 *
2274 * This code must be sure never to sleep through a hangup.
Joe Petersona88a69c2009-01-02 13:40:53 +00002275 *
2276 * Locking: output_lock to protect column state and space left
2277 * (note that the process_output*() functions take this
2278 * lock themselves)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002279 */
Alan Cox4edf1822008-02-08 04:18:44 -08002280
Alan Cox11a96d12008-10-13 10:46:24 +01002281static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
Joe Petersona88a69c2009-01-02 13:40:53 +00002282 const unsigned char *buf, size_t nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002283{
2284 const unsigned char *b = buf;
Peter Zijlstra97d9e282014-09-24 10:18:51 +02002285 DEFINE_WAIT_FUNC(wait, woken_wake_function);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002286 int c;
2287 ssize_t retval = 0;
2288
2289 /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
2290 if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) {
2291 retval = tty_check_change(tty);
2292 if (retval)
2293 return retval;
2294 }
2295
Peter Hurley9356b532013-06-15 09:14:24 -04002296 down_read(&tty->termios_rwsem);
2297
Joe Petersona88a69c2009-01-02 13:40:53 +00002298 /* Write out any echoed characters that are still pending */
2299 process_echoes(tty);
Alan Cox300a6202009-01-02 13:41:04 +00002300
Linus Torvalds1da177e2005-04-16 15:20:36 -07002301 add_wait_queue(&tty->write_wait, &wait);
2302 while (1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002303 if (signal_pending(current)) {
2304 retval = -ERESTARTSYS;
2305 break;
2306 }
2307 if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) {
2308 retval = -EIO;
2309 break;
2310 }
Peter Hurley582f5592013-05-17 12:49:48 -04002311 if (O_OPOST(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002312 while (nr > 0) {
Joe Petersona88a69c2009-01-02 13:40:53 +00002313 ssize_t num = process_output_block(tty, b, nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002314 if (num < 0) {
2315 if (num == -EAGAIN)
2316 break;
2317 retval = num;
2318 goto break_out;
2319 }
2320 b += num;
2321 nr -= num;
2322 if (nr == 0)
2323 break;
2324 c = *b;
Joe Petersona88a69c2009-01-02 13:40:53 +00002325 if (process_output(c, tty) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002326 break;
2327 b++; nr--;
2328 }
Alan Coxf34d7a52008-04-30 00:54:13 -07002329 if (tty->ops->flush_chars)
2330 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002331 } else {
Peter Hurley42910862014-05-03 14:04:59 +02002332 struct n_tty_data *ldata = tty->disc_data;
2333
Roman Zippeld6afe272005-07-07 17:56:55 -07002334 while (nr > 0) {
Peter Hurley42910862014-05-03 14:04:59 +02002335 mutex_lock(&ldata->output_lock);
Alan Coxf34d7a52008-04-30 00:54:13 -07002336 c = tty->ops->write(tty, b, nr);
Peter Hurley42910862014-05-03 14:04:59 +02002337 mutex_unlock(&ldata->output_lock);
Roman Zippeld6afe272005-07-07 17:56:55 -07002338 if (c < 0) {
2339 retval = c;
2340 goto break_out;
2341 }
2342 if (!c)
2343 break;
2344 b += c;
2345 nr -= c;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002346 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002347 }
2348 if (!nr)
2349 break;
2350 if (file->f_flags & O_NONBLOCK) {
2351 retval = -EAGAIN;
2352 break;
2353 }
Peter Hurley9356b532013-06-15 09:14:24 -04002354 up_read(&tty->termios_rwsem);
2355
Peter Zijlstra97d9e282014-09-24 10:18:51 +02002356 wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
Peter Hurley9356b532013-06-15 09:14:24 -04002357
2358 down_read(&tty->termios_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002359 }
2360break_out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002361 remove_wait_queue(&tty->write_wait, &wait);
Peter Hurley87108bc2016-01-09 21:45:14 -08002362 if (nr && tty->fasync)
Thomas Pfaffff8cb0f2009-01-02 13:47:13 +00002363 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Peter Hurley9356b532013-06-15 09:14:24 -04002364 up_read(&tty->termios_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002365 return (b - buf) ? b - buf : retval;
2366}
2367
2368/**
Alan Cox11a96d12008-10-13 10:46:24 +01002369 * n_tty_poll - poll method for N_TTY
Linus Torvalds1da177e2005-04-16 15:20:36 -07002370 * @tty: terminal device
2371 * @file: file accessing it
2372 * @wait: poll table
2373 *
2374 * Called when the line discipline is asked to poll() for data or
2375 * for special events. This code is not serialized with respect to
2376 * other events save open/close.
2377 *
2378 * This code must be sure never to sleep through a hangup.
2379 * Called without the kernel lock held - fine
Linus Torvalds1da177e2005-04-16 15:20:36 -07002380 */
Alan Cox4edf1822008-02-08 04:18:44 -08002381
Alan Cox11a96d12008-10-13 10:46:24 +01002382static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
Alan Cox4edf1822008-02-08 04:18:44 -08002383 poll_table *wait)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002384{
2385 unsigned int mask = 0;
2386
2387 poll_wait(file, &tty->read_wait, wait);
2388 poll_wait(file, &tty->write_wait, wait);
Peter Hurley1a486322015-04-13 13:24:34 -04002389 if (check_other_done(tty))
2390 mask |= POLLHUP;
Francesco Ruggeric4dc3042014-10-10 13:09:53 -07002391 if (input_available_p(tty, 1))
2392 mask |= POLLIN | POLLRDNORM;
Francesco Ruggeric4dc3042014-10-10 13:09:53 -07002393 if (tty->packet && tty->link->ctrl_status)
2394 mask |= POLLPRI | POLLIN | POLLRDNORM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002395 if (tty_hung_up_p(file))
2396 mask |= POLLHUP;
Alan Coxf34d7a52008-04-30 00:54:13 -07002397 if (tty->ops->write && !tty_is_writelocked(tty) &&
2398 tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
2399 tty_write_room(tty) > 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002400 mask |= POLLOUT | POLLWRNORM;
2401 return mask;
2402}
2403
Jiri Slaby57c94122012-10-18 22:26:43 +02002404static unsigned long inq_canon(struct n_tty_data *ldata)
Alan Cox47afa7a2008-10-13 10:44:17 +01002405{
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002406 size_t nr, head, tail;
Alan Cox47afa7a2008-10-13 10:44:17 +01002407
Peter Hurleya73d3d62013-06-15 09:14:25 -04002408 if (ldata->canon_head == ldata->read_tail)
Alan Cox47afa7a2008-10-13 10:44:17 +01002409 return 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002410 head = ldata->canon_head;
2411 tail = ldata->read_tail;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002412 nr = head - tail;
Alan Cox47afa7a2008-10-13 10:44:17 +01002413 /* Skip EOF-chars.. */
2414 while (head != tail) {
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002415 if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) &&
2416 read_buf(ldata, tail) == __DISABLED_CHAR)
Alan Cox47afa7a2008-10-13 10:44:17 +01002417 nr--;
Peter Hurleybc5a5e32013-06-15 09:14:21 -04002418 tail++;
Alan Cox47afa7a2008-10-13 10:44:17 +01002419 }
2420 return nr;
2421}
2422
2423static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
2424 unsigned int cmd, unsigned long arg)
2425{
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002426 struct n_tty_data *ldata = tty->disc_data;
Alan Cox47afa7a2008-10-13 10:44:17 +01002427 int retval;
2428
2429 switch (cmd) {
2430 case TIOCOUTQ:
2431 return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
2432 case TIOCINQ:
Peter Hurley6d76bd22013-06-15 09:14:26 -04002433 down_write(&tty->termios_rwsem);
Alan Cox47afa7a2008-10-13 10:44:17 +01002434 if (L_ICANON(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02002435 retval = inq_canon(ldata);
Peter Hurley6d76bd22013-06-15 09:14:26 -04002436 else
2437 retval = read_cnt(ldata);
2438 up_write(&tty->termios_rwsem);
Alan Cox47afa7a2008-10-13 10:44:17 +01002439 return put_user(retval, (unsigned int __user *) arg);
2440 default:
2441 return n_tty_ioctl_helper(tty, file, cmd, arg);
2442 }
2443}
2444
Peter Hurley27228732016-01-09 21:35:19 -08002445static struct tty_ldisc_ops n_tty_ops = {
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002446 .magic = TTY_LDISC_MAGIC,
2447 .name = "n_tty",
2448 .open = n_tty_open,
2449 .close = n_tty_close,
2450 .flush_buffer = n_tty_flush_buffer,
Alan Cox11a96d12008-10-13 10:46:24 +01002451 .read = n_tty_read,
2452 .write = n_tty_write,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002453 .ioctl = n_tty_ioctl,
2454 .set_termios = n_tty_set_termios,
Alan Cox11a96d12008-10-13 10:46:24 +01002455 .poll = n_tty_poll,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002456 .receive_buf = n_tty_receive_buf,
Peter Hurleyf6c8dbe2013-06-15 07:28:28 -04002457 .write_wakeup = n_tty_write_wakeup,
Peter Hurley24a89d12013-06-15 09:14:15 -04002458 .receive_buf2 = n_tty_receive_buf2,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002459};
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -08002460
2461/**
2462 * n_tty_inherit_ops - inherit N_TTY methods
2463 * @ops: struct tty_ldisc_ops where to save N_TTY methods
2464 *
Peter Hurley27228732016-01-09 21:35:19 -08002465 * Enables a 'subclass' line discipline to 'inherit' N_TTY methods.
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -08002466 */
2467
2468void n_tty_inherit_ops(struct tty_ldisc_ops *ops)
2469{
Peter Hurley27228732016-01-09 21:35:19 -08002470 *ops = n_tty_ops;
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -08002471 ops->owner = NULL;
2472 ops->refcount = ops->flags = 0;
2473}
2474EXPORT_SYMBOL_GPL(n_tty_inherit_ops);
Peter Hurley27228732016-01-09 21:35:19 -08002475
2476void __init n_tty_init(void)
2477{
2478 tty_register_ldisc(N_TTY, &n_tty_ops);
2479}