blob: 905a6fa5250e3cb43c6faefee04dfd1e5321b315 [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
55/* number of characters left in xmit buffer before select has we have room */
56#define WAKEUP_CHARS 256
57
58/*
59 * This defines the low- and high-watermarks for throttling and
60 * unthrottling the TTY driver. These watermarks are used for
61 * controlling the space in the read buffer.
62 */
63#define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */
Thorsten Wißmannbbd20752011-12-08 17:47:33 +010064#define TTY_THRESHOLD_UNTHROTTLE 128
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
Joe Petersona88a69c2009-01-02 13:40:53 +000066/*
67 * Special byte codes used in the echo buffer to represent operations
68 * or special handling of characters. Bytes in the echo buffer that
69 * are not part of such special blocks are treated as normal character
70 * codes.
71 */
72#define ECHO_OP_START 0xff
73#define ECHO_OP_MOVE_BACK_COL 0x80
74#define ECHO_OP_SET_CANON_COL 0x81
75#define ECHO_OP_ERASE_TAB 0x82
76
Jiri Slaby70ece7a2012-10-18 22:26:38 +020077struct n_tty_data {
Jiri Slaby53c5ee22012-10-18 22:26:39 +020078 unsigned int column;
79 unsigned long overrun_time;
80 int num_overrun;
81
82 unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
83 unsigned char echo_overrun:1;
Jiri Slaby3fe780b2012-10-18 22:26:40 +020084
85 DECLARE_BITMAP(process_char_map, 256);
86 DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE);
Jiri Slabyba2e68a2012-10-18 22:26:41 +020087
88 char *read_buf;
89 int read_head;
90 int read_tail;
91 int read_cnt;
92
93 unsigned char *echo_buf;
94 unsigned int echo_pos;
95 unsigned int echo_cnt;
96
97 int canon_data;
98 unsigned long canon_head;
99 unsigned int canon_column;
Jiri Slabybddc7152012-10-18 22:26:42 +0200100
101 struct mutex atomic_read_lock;
102 struct mutex output_lock;
103 struct mutex echo_lock;
Ivo Sieben98001212013-01-28 13:32:01 +0100104 raw_spinlock_t read_lock;
Jiri Slaby70ece7a2012-10-18 22:26:38 +0200105};
106
Miloslav Trmac522ed772007-07-15 23:40:56 -0700107static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
108 unsigned char __user *ptr)
109{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200110 struct n_tty_data *ldata = tty->disc_data;
111
112 tty_audit_add_data(tty, &x, 1, ldata->icanon);
Miloslav Trmac522ed772007-07-15 23:40:56 -0700113 return put_user(x, ptr);
114}
115
Linus Torvalds55db4c62011-06-04 06:33:24 +0900116/**
117 * n_tty_set__room - receive space
118 * @tty: terminal
119 *
120 * Called by the driver to find out how much data it is
121 * permitted to feed to the line discipline without any being lost
122 * and thus to manage flow control. Not serialized. Answers for the
123 * "instant".
124 */
125
126static void n_tty_set_room(struct tty_struct *tty)
127{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200128 struct n_tty_data *ldata = tty->disc_data;
Jaeden Amero090abf72012-07-27 08:43:11 -0500129 int left;
Linus Torvalds55db4c62011-06-04 06:33:24 +0900130 int old_left;
131
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200132 /* ldata->read_cnt is not read locked ? */
Jaeden Amero090abf72012-07-27 08:43:11 -0500133 if (I_PARMRK(tty)) {
134 /* Multiply read_cnt by 3, since each byte might take up to
135 * three times as many spaces when PARMRK is set (depending on
136 * its flags, e.g. parity error). */
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200137 left = N_TTY_BUF_SIZE - ldata->read_cnt * 3 - 1;
Jaeden Amero090abf72012-07-27 08:43:11 -0500138 } else
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200139 left = N_TTY_BUF_SIZE - ldata->read_cnt - 1;
Jaeden Amero090abf72012-07-27 08:43:11 -0500140
Linus Torvalds55db4c62011-06-04 06:33:24 +0900141 /*
142 * If we are doing input canonicalization, and there are no
143 * pending newlines, let characters through without limit, so
144 * that erase characters will be handled. Other excess
145 * characters will be beeped.
146 */
147 if (left <= 0)
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200148 left = ldata->icanon && !ldata->canon_data;
Linus Torvalds55db4c62011-06-04 06:33:24 +0900149 old_left = tty->receive_room;
150 tty->receive_room = left;
151
152 /* Did this open up the receive buffer? We may need to flip */
Jiri Slabyecbbfd42012-10-18 22:26:47 +0200153 if (left && !old_left) {
154 WARN_RATELIMIT(tty->port->itty == NULL,
Sasha Levincadf7482012-10-25 14:26:35 -0400155 "scheduling with invalid itty\n");
Peter Hurley21622932013-03-11 16:44:21 -0400156 /* see if ldisc has been killed - if so, this means that
157 * even though the ldisc has been halted and ->buf.work
158 * cancelled, ->buf.work is about to be rescheduled
159 */
160 WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags),
161 "scheduling buffer work for halted ldisc\n");
Jiri Slabyecbbfd42012-10-18 22:26:47 +0200162 schedule_work(&tty->port->buf.work);
163 }
Linus Torvalds55db4c62011-06-04 06:33:24 +0900164}
165
Jiri Slaby57c94122012-10-18 22:26:43 +0200166static void put_tty_queue_nolock(unsigned char c, struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167{
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200168 if (ldata->read_cnt < N_TTY_BUF_SIZE) {
169 ldata->read_buf[ldata->read_head] = c;
170 ldata->read_head = (ldata->read_head + 1) & (N_TTY_BUF_SIZE-1);
171 ldata->read_cnt++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 }
173}
174
Alan Cox17b82062008-10-13 10:45:06 +0100175/**
176 * put_tty_queue - add character to tty
177 * @c: character
Jiri Slaby57c94122012-10-18 22:26:43 +0200178 * @ldata: n_tty data
Alan Cox17b82062008-10-13 10:45:06 +0100179 *
180 * Add a character to the tty read_buf queue. This is done under the
181 * read_lock to serialize character addition and also to protect us
182 * against parallel reads or flushes
183 */
184
Jiri Slaby57c94122012-10-18 22:26:43 +0200185static void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186{
187 unsigned long flags;
188 /*
189 * The problem of stomping on the buffers ends here.
190 * Why didn't anyone see this one coming? --AJK
191 */
Ivo Sieben98001212013-01-28 13:32:01 +0100192 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Jiri Slaby57c94122012-10-18 22:26:43 +0200193 put_tty_queue_nolock(c, ldata);
Ivo Sieben98001212013-01-28 13:32:01 +0100194 raw_spin_unlock_irqrestore(&ldata->read_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195}
196
197/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 * reset_buffer_flags - reset buffer state
199 * @tty: terminal to reset
200 *
Peter Hurley25518c62013-03-11 16:44:31 -0400201 * Reset the read buffer counters and clear the flags.
202 * Called from n_tty_open() and n_tty_flush_buffer().
Alan Cox17b82062008-10-13 10:45:06 +0100203 *
204 * Locking: tty_read_lock for read fields.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000206
Peter Hurleyb66f4fa2013-03-11 16:44:32 -0400207static void reset_buffer_flags(struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208{
209 unsigned long flags;
210
Ivo Sieben98001212013-01-28 13:32:01 +0100211 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200212 ldata->read_head = ldata->read_tail = ldata->read_cnt = 0;
Ivo Sieben98001212013-01-28 13:32:01 +0100213 raw_spin_unlock_irqrestore(&ldata->read_lock, flags);
Joe Petersona88a69c2009-01-02 13:40:53 +0000214
Jiri Slabybddc7152012-10-18 22:26:42 +0200215 mutex_lock(&ldata->echo_lock);
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200216 ldata->echo_pos = ldata->echo_cnt = ldata->echo_overrun = 0;
Jiri Slabybddc7152012-10-18 22:26:42 +0200217 mutex_unlock(&ldata->echo_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000218
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200219 ldata->canon_head = ldata->canon_data = ldata->erasing = 0;
Jiri Slaby3fe780b2012-10-18 22:26:40 +0200220 bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221}
222
Peter Hurleya30737a2013-03-11 16:44:22 -0400223static void n_tty_packet_mode_flush(struct tty_struct *tty)
224{
225 unsigned long flags;
226
227 spin_lock_irqsave(&tty->ctrl_lock, flags);
228 if (tty->link->packet) {
229 tty->ctrl_status |= TIOCPKT_FLUSHREAD;
230 wake_up_interruptible(&tty->link->read_wait);
231 }
232 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
233}
234
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235/**
236 * n_tty_flush_buffer - clean input queue
237 * @tty: terminal device
238 *
Peter Hurley25518c62013-03-11 16:44:31 -0400239 * Flush the input buffer. Called when the tty layer wants the
240 * buffer flushed (eg at hangup) or when the N_TTY line discipline
241 * internally has to clean the pending queue (for example some signals).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 *
Alan Cox17b82062008-10-13 10:45:06 +0100243 * Locking: ctrl_lock, read_lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 */
Alan Cox4edf1822008-02-08 04:18:44 -0800245
246static void n_tty_flush_buffer(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247{
Peter Hurleyb66f4fa2013-03-11 16:44:32 -0400248 reset_buffer_flags(tty->disc_data);
249 n_tty_set_room(tty);
Alan Cox4edf1822008-02-08 04:18:44 -0800250
Peter Hurleya30737a2013-03-11 16:44:22 -0400251 if (tty->link)
252 n_tty_packet_mode_flush(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253}
254
255/**
256 * n_tty_chars_in_buffer - report available bytes
257 * @tty: tty device
258 *
259 * Report the number of characters buffered to be delivered to user
Alan Cox4edf1822008-02-08 04:18:44 -0800260 * at this instant in time.
Alan Cox17b82062008-10-13 10:45:06 +0100261 *
262 * Locking: read_lock
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 */
Alan Cox4edf1822008-02-08 04:18:44 -0800264
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
266{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200267 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 unsigned long flags;
269 ssize_t n = 0;
270
Ivo Sieben98001212013-01-28 13:32:01 +0100271 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200272 if (!ldata->icanon) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200273 n = ldata->read_cnt;
274 } else if (ldata->canon_data) {
275 n = (ldata->canon_head > ldata->read_tail) ?
276 ldata->canon_head - ldata->read_tail :
277 ldata->canon_head + (N_TTY_BUF_SIZE - ldata->read_tail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 }
Ivo Sieben98001212013-01-28 13:32:01 +0100279 raw_spin_unlock_irqrestore(&ldata->read_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 return n;
281}
282
283/**
284 * is_utf8_continuation - utf8 multibyte check
285 * @c: byte to check
286 *
287 * Returns true if the utf8 character 'c' is a multibyte continuation
288 * character. We use this to correctly compute the on screen size
289 * of the character when printing
290 */
Alan Cox4edf1822008-02-08 04:18:44 -0800291
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292static inline int is_utf8_continuation(unsigned char c)
293{
294 return (c & 0xc0) == 0x80;
295}
296
297/**
298 * is_continuation - multibyte check
299 * @c: byte to check
300 *
301 * Returns true if the utf8 character 'c' is a multibyte continuation
302 * character and the terminal is in unicode mode.
303 */
Alan Cox4edf1822008-02-08 04:18:44 -0800304
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305static inline int is_continuation(unsigned char c, struct tty_struct *tty)
306{
307 return I_IUTF8(tty) && is_utf8_continuation(c);
308}
309
310/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000311 * do_output_char - output one character
312 * @c: character (or partial unicode symbol)
313 * @tty: terminal device
314 * @space: space available in tty driver write buffer
315 *
316 * This is a helper function that handles one output character
317 * (including special characters like TAB, CR, LF, etc.),
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600318 * doing OPOST processing and putting the results in the
319 * tty driver's write buffer.
Joe Petersona88a69c2009-01-02 13:40:53 +0000320 *
321 * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY
322 * and NLDLY. They simply aren't relevant in the world today.
323 * If you ever need them, add them here.
324 *
325 * Returns the number of bytes of buffer space used or -1 if
326 * no space left.
327 *
328 * Locking: should be called under the output_lock to protect
329 * the column state and space left in the buffer
330 */
331
332static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
333{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200334 struct n_tty_data *ldata = tty->disc_data;
Joe Petersona88a69c2009-01-02 13:40:53 +0000335 int spaces;
336
337 if (!space)
338 return -1;
Alan Cox300a6202009-01-02 13:41:04 +0000339
Joe Petersona88a69c2009-01-02 13:40:53 +0000340 switch (c) {
341 case '\n':
342 if (O_ONLRET(tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200343 ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000344 if (O_ONLCR(tty)) {
345 if (space < 2)
346 return -1;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200347 ldata->canon_column = ldata->column = 0;
Linus Torvalds37f81fa2009-09-05 12:46:07 -0700348 tty->ops->write(tty, "\r\n", 2);
Joe Petersona88a69c2009-01-02 13:40:53 +0000349 return 2;
350 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200351 ldata->canon_column = ldata->column;
Joe Petersona88a69c2009-01-02 13:40:53 +0000352 break;
353 case '\r':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200354 if (O_ONOCR(tty) && ldata->column == 0)
Joe Petersona88a69c2009-01-02 13:40:53 +0000355 return 0;
356 if (O_OCRNL(tty)) {
357 c = '\n';
358 if (O_ONLRET(tty))
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200359 ldata->canon_column = ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000360 break;
361 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200362 ldata->canon_column = ldata->column = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000363 break;
364 case '\t':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200365 spaces = 8 - (ldata->column & 7);
Joe Petersona88a69c2009-01-02 13:40:53 +0000366 if (O_TABDLY(tty) == XTABS) {
367 if (space < spaces)
368 return -1;
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200369 ldata->column += spaces;
Joe Petersona88a69c2009-01-02 13:40:53 +0000370 tty->ops->write(tty, " ", spaces);
371 return spaces;
372 }
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200373 ldata->column += spaces;
Joe Petersona88a69c2009-01-02 13:40:53 +0000374 break;
375 case '\b':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200376 if (ldata->column > 0)
377 ldata->column--;
Joe Petersona88a69c2009-01-02 13:40:53 +0000378 break;
379 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000380 if (!iscntrl(c)) {
381 if (O_OLCUC(tty))
382 c = toupper(c);
383 if (!is_continuation(c, tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200384 ldata->column++;
Joe Petersona59c0d62009-01-02 13:43:25 +0000385 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000386 break;
387 }
388
389 tty_put_char(tty, c);
390 return 1;
391}
392
393/**
394 * process_output - output post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 * @c: character (or partial unicode symbol)
396 * @tty: terminal device
397 *
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600398 * Output one character with OPOST processing.
399 * Returns -1 when the output device is full and the character
400 * must be retried.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000402 * Locking: output_lock to protect column state and space left
403 * (also, this is called from n_tty_write under the
404 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 */
Alan Cox4edf1822008-02-08 04:18:44 -0800406
Joe Petersona88a69c2009-01-02 13:40:53 +0000407static int process_output(unsigned char c, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408{
Jiri Slabybddc7152012-10-18 22:26:42 +0200409 struct n_tty_data *ldata = tty->disc_data;
Joe Petersona88a69c2009-01-02 13:40:53 +0000410 int space, retval;
411
Jiri Slabybddc7152012-10-18 22:26:42 +0200412 mutex_lock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413
Alan Coxf34d7a52008-04-30 00:54:13 -0700414 space = tty_write_room(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +0000415 retval = do_output_char(c, tty, space);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416
Jiri Slabybddc7152012-10-18 22:26:42 +0200417 mutex_unlock(&ldata->output_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000418 if (retval < 0)
419 return -1;
420 else
421 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422}
423
424/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000425 * process_output_block - block post processor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 * @tty: terminal device
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600427 * @buf: character buffer
428 * @nr: number of bytes to output
429 *
430 * Output a block of characters with OPOST processing.
431 * Returns the number of characters output.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 *
433 * This path is used to speed up block console writes, among other
434 * things when processing blocks of output data. It handles only
435 * the simple cases normally found and helps to generate blocks of
436 * symbols for the console driver and thus improve performance.
437 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000438 * Locking: output_lock to protect column state and space left
439 * (also, this is called from n_tty_write under the
440 * tty layer write lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 */
Alan Cox4edf1822008-02-08 04:18:44 -0800442
Joe Petersona88a69c2009-01-02 13:40:53 +0000443static ssize_t process_output_block(struct tty_struct *tty,
444 const unsigned char *buf, unsigned int nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200446 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 int space;
Thorsten Wißmannbbd20752011-12-08 17:47:33 +0100448 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 const unsigned char *cp;
450
Jiri Slabybddc7152012-10-18 22:26:42 +0200451 mutex_lock(&ldata->output_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000452
Alan Coxf34d7a52008-04-30 00:54:13 -0700453 space = tty_write_room(tty);
Alan Cox300a6202009-01-02 13:41:04 +0000454 if (!space) {
Jiri Slabybddc7152012-10-18 22:26:42 +0200455 mutex_unlock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 return 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000457 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 if (nr > space)
459 nr = space;
460
461 for (i = 0, cp = buf; i < nr; i++, cp++) {
Joe Petersona59c0d62009-01-02 13:43:25 +0000462 unsigned char c = *cp;
463
464 switch (c) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465 case '\n':
466 if (O_ONLRET(tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200467 ldata->column = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 if (O_ONLCR(tty))
469 goto break_out;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200470 ldata->canon_column = ldata->column;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 break;
472 case '\r':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200473 if (O_ONOCR(tty) && ldata->column == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474 goto break_out;
475 if (O_OCRNL(tty))
476 goto break_out;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200477 ldata->canon_column = ldata->column = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 break;
479 case '\t':
480 goto break_out;
481 case '\b':
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200482 if (ldata->column > 0)
483 ldata->column--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 break;
485 default:
Joe Petersona59c0d62009-01-02 13:43:25 +0000486 if (!iscntrl(c)) {
487 if (O_OLCUC(tty))
488 goto break_out;
489 if (!is_continuation(c, tty))
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200490 ldata->column++;
Joe Petersona59c0d62009-01-02 13:43:25 +0000491 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 break;
493 }
494 }
495break_out:
Alan Coxf34d7a52008-04-30 00:54:13 -0700496 i = tty->ops->write(tty, buf, i);
Joe Petersona88a69c2009-01-02 13:40:53 +0000497
Jiri Slabybddc7152012-10-18 22:26:42 +0200498 mutex_unlock(&ldata->output_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 return i;
500}
501
Joe Petersona88a69c2009-01-02 13:40:53 +0000502/**
503 * process_echoes - write pending echo characters
504 * @tty: terminal device
505 *
506 * Write previously buffered echo (and other ldisc-generated)
507 * characters to the tty.
508 *
509 * Characters generated by the ldisc (including echoes) need to
510 * be buffered because the driver's write buffer can fill during
511 * heavy program output. Echoing straight to the driver will
512 * often fail under these conditions, causing lost characters and
513 * resulting mismatches of ldisc state information.
514 *
515 * Since the ldisc state must represent the characters actually sent
516 * to the driver at the time of the write, operations like certain
517 * changes in column state are also saved in the buffer and executed
518 * here.
519 *
520 * A circular fifo buffer is used so that the most recent characters
521 * are prioritized. Also, when control characters are echoed with a
522 * prefixed "^", the pair is treated atomically and thus not separated.
523 *
524 * Locking: output_lock to protect column state and space left,
525 * echo_lock to protect the echo buffer
526 */
527
528static void process_echoes(struct tty_struct *tty)
529{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200530 struct n_tty_data *ldata = tty->disc_data;
Joe Petersona88a69c2009-01-02 13:40:53 +0000531 int space, nr;
532 unsigned char c;
533 unsigned char *cp, *buf_end;
534
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200535 if (!ldata->echo_cnt)
Joe Petersona88a69c2009-01-02 13:40:53 +0000536 return;
537
Jiri Slabybddc7152012-10-18 22:26:42 +0200538 mutex_lock(&ldata->output_lock);
539 mutex_lock(&ldata->echo_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000540
541 space = tty_write_room(tty);
542
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200543 buf_end = ldata->echo_buf + N_TTY_BUF_SIZE;
544 cp = ldata->echo_buf + ldata->echo_pos;
545 nr = ldata->echo_cnt;
Joe Petersona88a69c2009-01-02 13:40:53 +0000546 while (nr > 0) {
547 c = *cp;
548 if (c == ECHO_OP_START) {
549 unsigned char op;
550 unsigned char *opp;
551 int no_space_left = 0;
552
553 /*
554 * If the buffer byte is the start of a multi-byte
555 * operation, get the next byte, which is either the
556 * op code or a control character value.
557 */
558 opp = cp + 1;
559 if (opp == buf_end)
560 opp -= N_TTY_BUF_SIZE;
561 op = *opp;
Alan Cox300a6202009-01-02 13:41:04 +0000562
Joe Petersona88a69c2009-01-02 13:40:53 +0000563 switch (op) {
564 unsigned int num_chars, num_bs;
565
566 case ECHO_OP_ERASE_TAB:
567 if (++opp == buf_end)
568 opp -= N_TTY_BUF_SIZE;
569 num_chars = *opp;
570
571 /*
572 * Determine how many columns to go back
573 * in order to erase the tab.
574 * This depends on the number of columns
575 * used by other characters within the tab
576 * area. If this (modulo 8) count is from
577 * the start of input rather than from a
578 * previous tab, we offset by canon column.
579 * Otherwise, tab spacing is normal.
580 */
581 if (!(num_chars & 0x80))
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200582 num_chars += ldata->canon_column;
Joe Petersona88a69c2009-01-02 13:40:53 +0000583 num_bs = 8 - (num_chars & 7);
584
585 if (num_bs > space) {
586 no_space_left = 1;
587 break;
588 }
589 space -= num_bs;
590 while (num_bs--) {
591 tty_put_char(tty, '\b');
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200592 if (ldata->column > 0)
593 ldata->column--;
Joe Petersona88a69c2009-01-02 13:40:53 +0000594 }
595 cp += 3;
596 nr -= 3;
597 break;
598
599 case ECHO_OP_SET_CANON_COL:
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200600 ldata->canon_column = ldata->column;
Joe Petersona88a69c2009-01-02 13:40:53 +0000601 cp += 2;
602 nr -= 2;
603 break;
604
605 case ECHO_OP_MOVE_BACK_COL:
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200606 if (ldata->column > 0)
607 ldata->column--;
Joe Petersona88a69c2009-01-02 13:40:53 +0000608 cp += 2;
609 nr -= 2;
610 break;
611
612 case ECHO_OP_START:
613 /* This is an escaped echo op start code */
614 if (!space) {
615 no_space_left = 1;
616 break;
617 }
618 tty_put_char(tty, ECHO_OP_START);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200619 ldata->column++;
Joe Petersona88a69c2009-01-02 13:40:53 +0000620 space--;
621 cp += 2;
622 nr -= 2;
623 break;
624
625 default:
Joe Petersona88a69c2009-01-02 13:40:53 +0000626 /*
Joe Peterson62b26352009-09-09 15:03:47 -0600627 * If the op is not a special byte code,
628 * it is a ctrl char tagged to be echoed
629 * as "^X" (where X is the letter
630 * representing the control char).
631 * Note that we must ensure there is
632 * enough space for the whole ctrl pair.
633 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000634 */
Joe Peterson62b26352009-09-09 15:03:47 -0600635 if (space < 2) {
636 no_space_left = 1;
637 break;
638 }
639 tty_put_char(tty, '^');
640 tty_put_char(tty, op ^ 0100);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200641 ldata->column += 2;
Joe Peterson62b26352009-09-09 15:03:47 -0600642 space -= 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000643 cp += 2;
644 nr -= 2;
645 }
646
647 if (no_space_left)
648 break;
649 } else {
Peter Hurley582f5592013-05-17 12:49:48 -0400650 if (O_OPOST(tty)) {
Joe Petersonee5aa7b2009-09-09 15:03:13 -0600651 int retval = do_output_char(c, tty, space);
652 if (retval < 0)
653 break;
654 space -= retval;
655 } else {
656 if (!space)
657 break;
658 tty_put_char(tty, c);
659 space -= 1;
660 }
Joe Petersona88a69c2009-01-02 13:40:53 +0000661 cp += 1;
662 nr -= 1;
663 }
664
665 /* When end of circular buffer reached, wrap around */
666 if (cp >= buf_end)
667 cp -= N_TTY_BUF_SIZE;
668 }
669
670 if (nr == 0) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200671 ldata->echo_pos = 0;
672 ldata->echo_cnt = 0;
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200673 ldata->echo_overrun = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000674 } else {
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200675 int num_processed = ldata->echo_cnt - nr;
676 ldata->echo_pos += num_processed;
677 ldata->echo_pos &= N_TTY_BUF_SIZE - 1;
678 ldata->echo_cnt = nr;
Joe Petersona88a69c2009-01-02 13:40:53 +0000679 if (num_processed > 0)
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200680 ldata->echo_overrun = 0;
Joe Petersona88a69c2009-01-02 13:40:53 +0000681 }
682
Jiri Slabybddc7152012-10-18 22:26:42 +0200683 mutex_unlock(&ldata->echo_lock);
684 mutex_unlock(&ldata->output_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000685
686 if (tty->ops->flush_chars)
687 tty->ops->flush_chars(tty);
688}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689
690/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000691 * add_echo_byte - add a byte to the echo buffer
692 * @c: unicode byte to echo
Jiri Slaby57c94122012-10-18 22:26:43 +0200693 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000694 *
695 * Add a character or operation byte to the echo buffer.
696 *
697 * Should be called under the echo lock to protect the echo buffer.
698 */
699
Jiri Slaby57c94122012-10-18 22:26:43 +0200700static void add_echo_byte(unsigned char c, struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000701{
702 int new_byte_pos;
703
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200704 if (ldata->echo_cnt == N_TTY_BUF_SIZE) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000705 /* Circular buffer is already at capacity */
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200706 new_byte_pos = ldata->echo_pos;
Joe Petersona88a69c2009-01-02 13:40:53 +0000707
708 /*
709 * Since the buffer start position needs to be advanced,
710 * be sure to step by a whole operation byte group.
711 */
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200712 if (ldata->echo_buf[ldata->echo_pos] == ECHO_OP_START) {
713 if (ldata->echo_buf[(ldata->echo_pos + 1) &
Joe Petersona88a69c2009-01-02 13:40:53 +0000714 (N_TTY_BUF_SIZE - 1)] ==
715 ECHO_OP_ERASE_TAB) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200716 ldata->echo_pos += 3;
717 ldata->echo_cnt -= 2;
Joe Petersona88a69c2009-01-02 13:40:53 +0000718 } else {
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200719 ldata->echo_pos += 2;
720 ldata->echo_cnt -= 1;
Joe Petersona88a69c2009-01-02 13:40:53 +0000721 }
722 } else {
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200723 ldata->echo_pos++;
Joe Petersona88a69c2009-01-02 13:40:53 +0000724 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200725 ldata->echo_pos &= N_TTY_BUF_SIZE - 1;
Joe Petersona88a69c2009-01-02 13:40:53 +0000726
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200727 ldata->echo_overrun = 1;
Joe Petersona88a69c2009-01-02 13:40:53 +0000728 } else {
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200729 new_byte_pos = ldata->echo_pos + ldata->echo_cnt;
Joe Petersona88a69c2009-01-02 13:40:53 +0000730 new_byte_pos &= N_TTY_BUF_SIZE - 1;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200731 ldata->echo_cnt++;
Joe Petersona88a69c2009-01-02 13:40:53 +0000732 }
733
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200734 ldata->echo_buf[new_byte_pos] = c;
Joe Petersona88a69c2009-01-02 13:40:53 +0000735}
736
737/**
738 * echo_move_back_col - add operation to move back a column
Jiri Slaby57c94122012-10-18 22:26:43 +0200739 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000740 *
741 * Add an operation to the echo buffer to move back one column.
742 *
743 * Locking: echo_lock to protect the echo buffer
744 */
745
Jiri Slaby57c94122012-10-18 22:26:43 +0200746static void echo_move_back_col(struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000747{
Jiri Slabybddc7152012-10-18 22:26:42 +0200748 mutex_lock(&ldata->echo_lock);
Jiri Slaby57c94122012-10-18 22:26:43 +0200749 add_echo_byte(ECHO_OP_START, ldata);
750 add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata);
Jiri Slabybddc7152012-10-18 22:26:42 +0200751 mutex_unlock(&ldata->echo_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000752}
753
754/**
755 * echo_set_canon_col - add operation to set the canon column
Jiri Slaby57c94122012-10-18 22:26:43 +0200756 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000757 *
758 * Add an operation to the echo buffer to set the canon column
759 * to the current column.
760 *
761 * Locking: echo_lock to protect the echo buffer
762 */
763
Jiri Slaby57c94122012-10-18 22:26:43 +0200764static void echo_set_canon_col(struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000765{
Jiri Slabybddc7152012-10-18 22:26:42 +0200766 mutex_lock(&ldata->echo_lock);
Jiri Slaby57c94122012-10-18 22:26:43 +0200767 add_echo_byte(ECHO_OP_START, ldata);
768 add_echo_byte(ECHO_OP_SET_CANON_COL, ldata);
Jiri Slabybddc7152012-10-18 22:26:42 +0200769 mutex_unlock(&ldata->echo_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000770}
771
772/**
773 * echo_erase_tab - add operation to erase a tab
774 * @num_chars: number of character columns already used
775 * @after_tab: true if num_chars starts after a previous tab
Jiri Slaby57c94122012-10-18 22:26:43 +0200776 * @ldata: n_tty data
Joe Petersona88a69c2009-01-02 13:40:53 +0000777 *
778 * Add an operation to the echo buffer to erase a tab.
779 *
780 * Called by the eraser function, which knows how many character
781 * columns have been used since either a previous tab or the start
782 * of input. This information will be used later, along with
783 * canon column (if applicable), to go back the correct number
784 * of columns.
785 *
786 * Locking: echo_lock to protect the echo buffer
787 */
788
789static void echo_erase_tab(unsigned int num_chars, int after_tab,
Jiri Slaby57c94122012-10-18 22:26:43 +0200790 struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000791{
Jiri Slabybddc7152012-10-18 22:26:42 +0200792 mutex_lock(&ldata->echo_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000793
Jiri Slaby57c94122012-10-18 22:26:43 +0200794 add_echo_byte(ECHO_OP_START, ldata);
795 add_echo_byte(ECHO_OP_ERASE_TAB, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000796
797 /* We only need to know this modulo 8 (tab spacing) */
798 num_chars &= 7;
799
800 /* Set the high bit as a flag if num_chars is after a previous tab */
801 if (after_tab)
802 num_chars |= 0x80;
Alan Cox300a6202009-01-02 13:41:04 +0000803
Jiri Slaby57c94122012-10-18 22:26:43 +0200804 add_echo_byte(num_chars, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000805
Jiri Slabybddc7152012-10-18 22:26:42 +0200806 mutex_unlock(&ldata->echo_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000807}
808
809/**
810 * echo_char_raw - echo a character raw
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 * @c: unicode byte to echo
812 * @tty: terminal device
813 *
Alan Cox4edf1822008-02-08 04:18:44 -0800814 * Echo user input back onto the screen. This must be called only when
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 * L_ECHO(tty) is true. Called from the driver receive_buf path.
Alan Cox17b82062008-10-13 10:45:06 +0100816 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000817 * This variant does not treat control characters specially.
818 *
819 * Locking: echo_lock to protect the echo buffer
820 */
821
Jiri Slaby57c94122012-10-18 22:26:43 +0200822static void echo_char_raw(unsigned char c, struct n_tty_data *ldata)
Joe Petersona88a69c2009-01-02 13:40:53 +0000823{
Jiri Slabybddc7152012-10-18 22:26:42 +0200824 mutex_lock(&ldata->echo_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000825 if (c == ECHO_OP_START) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200826 add_echo_byte(ECHO_OP_START, ldata);
827 add_echo_byte(ECHO_OP_START, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000828 } else {
Jiri Slaby57c94122012-10-18 22:26:43 +0200829 add_echo_byte(c, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000830 }
Jiri Slabybddc7152012-10-18 22:26:42 +0200831 mutex_unlock(&ldata->echo_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000832}
833
834/**
835 * echo_char - echo a character
836 * @c: unicode byte to echo
837 * @tty: terminal device
838 *
839 * Echo user input back onto the screen. This must be called only when
840 * L_ECHO(tty) is true. Called from the driver receive_buf path.
841 *
Joe Peterson62b26352009-09-09 15:03:47 -0600842 * This variant tags control characters to be echoed as "^X"
843 * (where X is the letter representing the control char).
Joe Petersona88a69c2009-01-02 13:40:53 +0000844 *
845 * Locking: echo_lock to protect the echo buffer
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 */
847
848static void echo_char(unsigned char c, struct tty_struct *tty)
849{
Jiri Slabybddc7152012-10-18 22:26:42 +0200850 struct n_tty_data *ldata = tty->disc_data;
851
852 mutex_lock(&ldata->echo_lock);
Joe Petersona88a69c2009-01-02 13:40:53 +0000853
854 if (c == ECHO_OP_START) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200855 add_echo_byte(ECHO_OP_START, ldata);
856 add_echo_byte(ECHO_OP_START, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000857 } else {
Joe Peterson62b26352009-09-09 15:03:47 -0600858 if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t')
Jiri Slaby57c94122012-10-18 22:26:43 +0200859 add_echo_byte(ECHO_OP_START, ldata);
860 add_echo_byte(c, ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +0000861 }
862
Jiri Slabybddc7152012-10-18 22:26:42 +0200863 mutex_unlock(&ldata->echo_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864}
865
Alan Cox17b82062008-10-13 10:45:06 +0100866/**
Joe Petersona88a69c2009-01-02 13:40:53 +0000867 * finish_erasing - complete erase
Jiri Slaby57c94122012-10-18 22:26:43 +0200868 * @ldata: n_tty data
Alan Cox17b82062008-10-13 10:45:06 +0100869 */
Joe Petersona88a69c2009-01-02 13:40:53 +0000870
Jiri Slaby57c94122012-10-18 22:26:43 +0200871static inline void finish_erasing(struct n_tty_data *ldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200873 if (ldata->erasing) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200874 echo_char_raw('/', ldata);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200875 ldata->erasing = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 }
877}
878
879/**
880 * eraser - handle erase function
881 * @c: character input
882 * @tty: terminal device
883 *
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200884 * Perform erase and necessary output when an erase character is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 * present in the stream from the driver layer. Handles the complexities
886 * of UTF-8 multibyte symbols.
Alan Cox17b82062008-10-13 10:45:06 +0100887 *
Joe Petersona88a69c2009-01-02 13:40:53 +0000888 * Locking: read_lock for tty buffers
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 */
Alan Cox4edf1822008-02-08 04:18:44 -0800890
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891static void eraser(unsigned char c, struct tty_struct *tty)
892{
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200893 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894 enum { ERASE, WERASE, KILL } kill_type;
895 int head, seen_alnums, cnt;
896 unsigned long flags;
897
Alan Cox17b82062008-10-13 10:45:06 +0100898 /* FIXME: locking needed ? */
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200899 if (ldata->read_head == ldata->canon_head) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +0000900 /* process_output('\a', tty); */ /* what do you think? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 return;
902 }
903 if (c == ERASE_CHAR(tty))
904 kill_type = ERASE;
905 else if (c == WERASE_CHAR(tty))
906 kill_type = WERASE;
907 else {
908 if (!L_ECHO(tty)) {
Ivo Sieben98001212013-01-28 13:32:01 +0100909 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200910 ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) &
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 (N_TTY_BUF_SIZE - 1));
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200912 ldata->read_head = ldata->canon_head;
Ivo Sieben98001212013-01-28 13:32:01 +0100913 raw_spin_unlock_irqrestore(&ldata->read_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914 return;
915 }
916 if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
Ivo Sieben98001212013-01-28 13:32:01 +0100917 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200918 ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) &
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 (N_TTY_BUF_SIZE - 1));
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200920 ldata->read_head = ldata->canon_head;
Ivo Sieben98001212013-01-28 13:32:01 +0100921 raw_spin_unlock_irqrestore(&ldata->read_lock, flags);
Jiri Slaby57c94122012-10-18 22:26:43 +0200922 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 echo_char(KILL_CHAR(tty), tty);
924 /* Add a newline if ECHOK is on and ECHOKE is off. */
925 if (L_ECHOK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +0200926 echo_char_raw('\n', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 return;
928 }
929 kill_type = KILL;
930 }
931
932 seen_alnums = 0;
Alan Cox17b82062008-10-13 10:45:06 +0100933 /* FIXME: Locking ?? */
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200934 while (ldata->read_head != ldata->canon_head) {
935 head = ldata->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700936
937 /* erase a single possibly multibyte character */
938 do {
939 head = (head - 1) & (N_TTY_BUF_SIZE-1);
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200940 c = ldata->read_buf[head];
941 } while (is_continuation(c, tty) && head != ldata->canon_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942
943 /* do not partially erase */
944 if (is_continuation(c, tty))
945 break;
946
947 if (kill_type == WERASE) {
948 /* Equivalent to BSD's ALTWERASE. */
949 if (isalnum(c) || c == '_')
950 seen_alnums++;
951 else if (seen_alnums)
952 break;
953 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200954 cnt = (ldata->read_head - head) & (N_TTY_BUF_SIZE-1);
Ivo Sieben98001212013-01-28 13:32:01 +0100955 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200956 ldata->read_head = head;
957 ldata->read_cnt -= cnt;
Ivo Sieben98001212013-01-28 13:32:01 +0100958 raw_spin_unlock_irqrestore(&ldata->read_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 if (L_ECHO(tty)) {
960 if (L_ECHOPRT(tty)) {
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200961 if (!ldata->erasing) {
Jiri Slaby57c94122012-10-18 22:26:43 +0200962 echo_char_raw('\\', ldata);
Jiri Slaby53c5ee22012-10-18 22:26:39 +0200963 ldata->erasing = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 }
965 /* if cnt > 1, output a multi-byte character */
966 echo_char(c, tty);
967 while (--cnt > 0) {
968 head = (head+1) & (N_TTY_BUF_SIZE-1);
Jiri Slaby57c94122012-10-18 22:26:43 +0200969 echo_char_raw(ldata->read_buf[head],
970 ldata);
971 echo_move_back_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972 }
973 } else if (kill_type == ERASE && !L_ECHOE(tty)) {
974 echo_char(ERASE_CHAR(tty), tty);
975 } else if (c == '\t') {
Joe Petersona88a69c2009-01-02 13:40:53 +0000976 unsigned int num_chars = 0;
977 int after_tab = 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200978 unsigned long tail = ldata->read_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979
Joe Petersona88a69c2009-01-02 13:40:53 +0000980 /*
981 * Count the columns used for characters
982 * since the start of input or after a
983 * previous tab.
984 * This info is used to go back the correct
985 * number of columns.
986 */
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200987 while (tail != ldata->canon_head) {
Joe Petersona88a69c2009-01-02 13:40:53 +0000988 tail = (tail-1) & (N_TTY_BUF_SIZE-1);
Jiri Slabyba2e68a2012-10-18 22:26:41 +0200989 c = ldata->read_buf[tail];
Joe Petersona88a69c2009-01-02 13:40:53 +0000990 if (c == '\t') {
991 after_tab = 1;
992 break;
Alan Cox300a6202009-01-02 13:41:04 +0000993 } else if (iscntrl(c)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 if (L_ECHOCTL(tty))
Joe Petersona88a69c2009-01-02 13:40:53 +0000995 num_chars += 2;
996 } else if (!is_continuation(c, tty)) {
997 num_chars++;
998 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 }
Jiri Slaby57c94122012-10-18 22:26:43 +02001000 echo_erase_tab(num_chars, after_tab, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001 } else {
1002 if (iscntrl(c) && L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001003 echo_char_raw('\b', ldata);
1004 echo_char_raw(' ', ldata);
1005 echo_char_raw('\b', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006 }
1007 if (!iscntrl(c) || L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001008 echo_char_raw('\b', ldata);
1009 echo_char_raw(' ', ldata);
1010 echo_char_raw('\b', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 }
1012 }
1013 }
1014 if (kill_type == ERASE)
1015 break;
1016 }
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001017 if (ldata->read_head == ldata->canon_head && L_ECHO(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001018 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019}
1020
1021/**
1022 * isig - handle the ISIG optio
1023 * @sig: signal
1024 * @tty: terminal
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025 *
Peter Hurley8c985d12013-03-06 08:38:19 -05001026 * Called when a signal is being sent due to terminal input.
1027 * Called from the driver receive_buf path so serialized.
Alan Cox17b82062008-10-13 10:45:06 +01001028 *
Peter Hurley8c985d12013-03-06 08:38:19 -05001029 * Locking: ctrl_lock
Linus Torvalds1da177e2005-04-16 15:20:36 -07001030 */
Alan Cox4edf1822008-02-08 04:18:44 -08001031
Peter Hurley8c985d12013-03-06 08:38:19 -05001032static inline void isig(int sig, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033{
Peter Hurley8c985d12013-03-06 08:38:19 -05001034 struct pid *tty_pgrp = tty_get_pgrp(tty);
1035 if (tty_pgrp) {
1036 kill_pgrp(tty_pgrp, sig, 1);
1037 put_pid(tty_pgrp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038 }
1039}
1040
1041/**
1042 * n_tty_receive_break - handle break
1043 * @tty: terminal
1044 *
1045 * An RS232 break event has been hit in the incoming bitstream. This
1046 * can cause a variety of events depending upon the termios settings.
1047 *
1048 * Called from the receive_buf path so single threaded.
1049 */
Alan Cox4edf1822008-02-08 04:18:44 -08001050
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051static inline void n_tty_receive_break(struct tty_struct *tty)
1052{
Jiri Slaby57c94122012-10-18 22:26:43 +02001053 struct n_tty_data *ldata = tty->disc_data;
1054
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055 if (I_IGNBRK(tty))
1056 return;
1057 if (I_BRKINT(tty)) {
Peter Hurley8c985d12013-03-06 08:38:19 -05001058 isig(SIGINT, tty);
1059 if (!L_NOFLSH(tty)) {
1060 n_tty_flush_buffer(tty);
1061 tty_driver_flush_buffer(tty);
1062 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001063 return;
1064 }
1065 if (I_PARMRK(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001066 put_tty_queue('\377', ldata);
1067 put_tty_queue('\0', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068 }
Jiri Slaby57c94122012-10-18 22:26:43 +02001069 put_tty_queue('\0', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070 wake_up_interruptible(&tty->read_wait);
1071}
1072
1073/**
1074 * n_tty_receive_overrun - handle overrun reporting
1075 * @tty: terminal
1076 *
1077 * Data arrived faster than we could process it. While the tty
1078 * driver has flagged this the bits that were missed are gone
1079 * forever.
1080 *
1081 * Called from the receive_buf path so single threaded. Does not
1082 * need locking as num_overrun and overrun_time are function
1083 * private.
1084 */
Alan Cox4edf1822008-02-08 04:18:44 -08001085
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086static inline void n_tty_receive_overrun(struct tty_struct *tty)
1087{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001088 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 char buf[64];
1090
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001091 ldata->num_overrun++;
1092 if (time_after(jiffies, ldata->overrun_time + HZ) ||
1093 time_after(ldata->overrun_time, jiffies)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 printk(KERN_WARNING "%s: %d input overrun(s)\n",
1095 tty_name(tty, buf),
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001096 ldata->num_overrun);
1097 ldata->overrun_time = jiffies;
1098 ldata->num_overrun = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099 }
1100}
1101
1102/**
1103 * n_tty_receive_parity_error - error notifier
1104 * @tty: terminal device
1105 * @c: character
1106 *
1107 * Process a parity error and queue the right data to indicate
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +02001108 * the error case if necessary. Locking as per n_tty_receive_buf.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001109 */
1110static inline void n_tty_receive_parity_error(struct tty_struct *tty,
1111 unsigned char c)
1112{
Jiri Slaby57c94122012-10-18 22:26:43 +02001113 struct n_tty_data *ldata = tty->disc_data;
1114
Alan Cox4edf1822008-02-08 04:18:44 -08001115 if (I_IGNPAR(tty))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117 if (I_PARMRK(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001118 put_tty_queue('\377', ldata);
1119 put_tty_queue('\0', ldata);
1120 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121 } else if (I_INPCK(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02001122 put_tty_queue('\0', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123 else
Jiri Slaby57c94122012-10-18 22:26:43 +02001124 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001125 wake_up_interruptible(&tty->read_wait);
1126}
1127
1128/**
1129 * n_tty_receive_char - perform processing
1130 * @tty: terminal device
1131 * @c: character
1132 *
1133 * Process an individual character of input received from the driver.
Alan Cox4edf1822008-02-08 04:18:44 -08001134 * This is serialized with respect to itself by the rules for the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135 * driver above.
1136 */
1137
1138static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
1139{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001140 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 unsigned long flags;
Joe Petersonacc71bb2009-01-02 13:43:32 +00001142 int parmrk;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001143
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001144 if (ldata->raw) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001145 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146 return;
1147 }
Alan Cox4edf1822008-02-08 04:18:44 -08001148
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 if (I_ISTRIP(tty))
1150 c &= 0x7f;
1151 if (I_IUCLC(tty) && L_IEXTEN(tty))
Alan Cox300a6202009-01-02 13:41:04 +00001152 c = tolower(c);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153
hyc@symas.com26df6d12010-06-22 10:14:49 -07001154 if (L_EXTPROC(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001155 put_tty_queue(c, ldata);
hyc@symas.com26df6d12010-06-22 10:14:49 -07001156 return;
1157 }
1158
Joe Peterson54d2a372008-02-06 01:37:59 -08001159 if (tty->stopped && !tty->flow_stopped && I_IXON(tty) &&
Joe Petersona88a69c2009-01-02 13:40:53 +00001160 I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) &&
1161 c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) {
Joe Peterson54d2a372008-02-06 01:37:59 -08001162 start_tty(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001163 process_echoes(tty);
1164 }
Joe Peterson54d2a372008-02-06 01:37:59 -08001165
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166 if (tty->closing) {
1167 if (I_IXON(tty)) {
Joe Petersona88a69c2009-01-02 13:40:53 +00001168 if (c == START_CHAR(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169 start_tty(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001170 process_echoes(tty);
Alan Cox300a6202009-01-02 13:41:04 +00001171 } else if (c == STOP_CHAR(tty))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172 stop_tty(tty);
1173 }
1174 return;
1175 }
1176
1177 /*
1178 * If the previous character was LNEXT, or we know that this
1179 * character is not one of the characters that we'll have to
1180 * handle specially, do shortcut processing to speed things
1181 * up.
1182 */
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001183 if (!test_bit(c, ldata->process_char_map) || ldata->lnext) {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001184 ldata->lnext = 0;
Joe Petersonacc71bb2009-01-02 13:43:32 +00001185 parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001186 if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001187 /* beep if no space */
Joe Peterson7e94b1d2009-01-02 13:43:40 +00001188 if (L_ECHO(tty))
1189 process_output('\a', tty);
Joe Petersonacc71bb2009-01-02 13:43:32 +00001190 return;
1191 }
1192 if (L_ECHO(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001193 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 /* Record the column of first canon char. */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001195 if (ldata->canon_head == ldata->read_head)
Jiri Slaby57c94122012-10-18 22:26:43 +02001196 echo_set_canon_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 echo_char(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001198 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001199 }
Joe Petersonacc71bb2009-01-02 13:43:32 +00001200 if (parmrk)
Jiri Slaby57c94122012-10-18 22:26:43 +02001201 put_tty_queue(c, ldata);
1202 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203 return;
1204 }
Alan Cox4edf1822008-02-08 04:18:44 -08001205
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 if (I_IXON(tty)) {
1207 if (c == START_CHAR(tty)) {
1208 start_tty(tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001209 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210 return;
1211 }
1212 if (c == STOP_CHAR(tty)) {
1213 stop_tty(tty);
1214 return;
1215 }
1216 }
Joe Peterson575537b32008-04-30 00:53:30 -07001217
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218 if (L_ISIG(tty)) {
1219 int signal;
1220 signal = SIGINT;
1221 if (c == INTR_CHAR(tty))
1222 goto send_signal;
1223 signal = SIGQUIT;
1224 if (c == QUIT_CHAR(tty))
1225 goto send_signal;
1226 signal = SIGTSTP;
1227 if (c == SUSP_CHAR(tty)) {
1228send_signal:
Joe Petersonec5b1152008-02-06 01:37:38 -08001229 if (!L_NOFLSH(tty)) {
1230 n_tty_flush_buffer(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001231 tty_driver_flush_buffer(tty);
Joe Petersonec5b1152008-02-06 01:37:38 -08001232 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001233 if (I_IXON(tty))
1234 start_tty(tty);
1235 if (L_ECHO(tty)) {
Joe Petersonec5b1152008-02-06 01:37:38 -08001236 echo_char(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001237 process_echoes(tty);
1238 }
Peter Hurley8c985d12013-03-06 08:38:19 -05001239 isig(signal, tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 return;
1241 }
1242 }
Joe Peterson575537b32008-04-30 00:53:30 -07001243
1244 if (c == '\r') {
1245 if (I_IGNCR(tty))
1246 return;
1247 if (I_ICRNL(tty))
1248 c = '\n';
1249 } else if (c == '\n' && I_INLCR(tty))
1250 c = '\r';
1251
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001252 if (ldata->icanon) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
1254 (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
1255 eraser(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001256 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 return;
1258 }
1259 if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001260 ldata->lnext = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261 if (L_ECHO(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001262 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263 if (L_ECHOCTL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001264 echo_char_raw('^', ldata);
1265 echo_char_raw('\b', ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +00001266 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 }
1268 }
1269 return;
1270 }
1271 if (c == REPRINT_CHAR(tty) && L_ECHO(tty) &&
1272 L_IEXTEN(tty)) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001273 unsigned long tail = ldata->canon_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274
Jiri Slaby57c94122012-10-18 22:26:43 +02001275 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276 echo_char(c, tty);
Jiri Slaby57c94122012-10-18 22:26:43 +02001277 echo_char_raw('\n', ldata);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001278 while (tail != ldata->read_head) {
1279 echo_char(ldata->read_buf[tail], tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
1281 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001282 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283 return;
1284 }
1285 if (c == '\n') {
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001286 if (ldata->read_cnt >= N_TTY_BUF_SIZE) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +00001287 if (L_ECHO(tty))
1288 process_output('\a', tty);
Joe Petersonacc71bb2009-01-02 13:43:32 +00001289 return;
1290 }
1291 if (L_ECHO(tty) || L_ECHONL(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001292 echo_char_raw('\n', ldata);
Joe Petersona88a69c2009-01-02 13:40:53 +00001293 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294 }
1295 goto handle_newline;
1296 }
1297 if (c == EOF_CHAR(tty)) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001298 if (ldata->read_cnt >= N_TTY_BUF_SIZE)
Joe Petersonacc71bb2009-01-02 13:43:32 +00001299 return;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001300 if (ldata->canon_head != ldata->read_head)
Alan Cox4edf1822008-02-08 04:18:44 -08001301 set_bit(TTY_PUSH, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302 c = __DISABLED_CHAR;
1303 goto handle_newline;
1304 }
1305 if ((c == EOL_CHAR(tty)) ||
1306 (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001307 parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty))
1308 ? 1 : 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001309 if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) {
Joe Peterson7e94b1d2009-01-02 13:43:40 +00001310 if (L_ECHO(tty))
1311 process_output('\a', tty);
Joe Petersonacc71bb2009-01-02 13:43:32 +00001312 return;
1313 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314 /*
1315 * XXX are EOL_CHAR and EOL2_CHAR echoed?!?
1316 */
1317 if (L_ECHO(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 /* Record the column of first canon char. */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001319 if (ldata->canon_head == ldata->read_head)
Jiri Slaby57c94122012-10-18 22:26:43 +02001320 echo_set_canon_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321 echo_char(c, tty);
Joe Petersona88a69c2009-01-02 13:40:53 +00001322 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001323 }
1324 /*
1325 * XXX does PARMRK doubling happen for
1326 * EOL_CHAR and EOL2_CHAR?
1327 */
Joe Petersonacc71bb2009-01-02 13:43:32 +00001328 if (parmrk)
Jiri Slaby57c94122012-10-18 22:26:43 +02001329 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330
Alan Cox4edf1822008-02-08 04:18:44 -08001331handle_newline:
Ivo Sieben98001212013-01-28 13:32:01 +01001332 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001333 set_bit(ldata->read_head, ldata->read_flags);
Jiri Slaby57c94122012-10-18 22:26:43 +02001334 put_tty_queue_nolock(c, ldata);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001335 ldata->canon_head = ldata->read_head;
1336 ldata->canon_data++;
Ivo Sieben98001212013-01-28 13:32:01 +01001337 raw_spin_unlock_irqrestore(&ldata->read_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
1339 if (waitqueue_active(&tty->read_wait))
1340 wake_up_interruptible(&tty->read_wait);
1341 return;
1342 }
1343 }
Alan Cox4edf1822008-02-08 04:18:44 -08001344
Joe Petersonacc71bb2009-01-02 13:43:32 +00001345 parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001346 if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
Joe Petersonacc71bb2009-01-02 13:43:32 +00001347 /* beep if no space */
Joe Peterson7e94b1d2009-01-02 13:43:40 +00001348 if (L_ECHO(tty))
1349 process_output('\a', tty);
Joe Petersonacc71bb2009-01-02 13:43:32 +00001350 return;
1351 }
1352 if (L_ECHO(tty)) {
Jiri Slaby57c94122012-10-18 22:26:43 +02001353 finish_erasing(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354 if (c == '\n')
Jiri Slaby57c94122012-10-18 22:26:43 +02001355 echo_char_raw('\n', ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356 else {
1357 /* Record the column of first canon char. */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001358 if (ldata->canon_head == ldata->read_head)
Jiri Slaby57c94122012-10-18 22:26:43 +02001359 echo_set_canon_col(ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360 echo_char(c, tty);
1361 }
Joe Petersona88a69c2009-01-02 13:40:53 +00001362 process_echoes(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001363 }
1364
Joe Petersonacc71bb2009-01-02 13:43:32 +00001365 if (parmrk)
Jiri Slaby57c94122012-10-18 22:26:43 +02001366 put_tty_queue(c, ldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001367
Jiri Slaby57c94122012-10-18 22:26:43 +02001368 put_tty_queue(c, ldata);
Alan Cox4edf1822008-02-08 04:18:44 -08001369}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370
Linus Torvalds1da177e2005-04-16 15:20:36 -07001371
1372/**
1373 * n_tty_write_wakeup - asynchronous I/O notifier
1374 * @tty: tty device
1375 *
1376 * Required for the ptys, serial driver etc. since processes
1377 * that attach themselves to the master and rely on ASYNC
1378 * IO must be woken up
1379 */
1380
1381static void n_tty_write_wakeup(struct tty_struct *tty)
1382{
Thomas Pfaffff8cb0f2009-01-02 13:47:13 +00001383 if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384 kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001385}
1386
1387/**
1388 * n_tty_receive_buf - data receive
1389 * @tty: terminal device
1390 * @cp: buffer
1391 * @fp: flag buffer
1392 * @count: characters
1393 *
1394 * Called by the terminal driver when a block of characters has
1395 * been received. This function must be called from soft contexts
1396 * not from interrupt context. The driver is responsible for making
1397 * calls one at a time and in order (or using flush_to_ldisc)
1398 */
Alan Cox4edf1822008-02-08 04:18:44 -08001399
Linus Torvalds55db4c62011-06-04 06:33:24 +09001400static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1401 char *fp, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001403 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404 const unsigned char *p;
1405 char *f, flags = TTY_NORMAL;
1406 int i;
1407 char buf[64];
1408 unsigned long cpuflags;
1409
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001410 if (ldata->real_raw) {
Ivo Sieben98001212013-01-28 13:32:01 +01001411 raw_spin_lock_irqsave(&ldata->read_lock, cpuflags);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001412 i = min(N_TTY_BUF_SIZE - ldata->read_cnt,
1413 N_TTY_BUF_SIZE - ldata->read_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414 i = min(count, i);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001415 memcpy(ldata->read_buf + ldata->read_head, cp, i);
1416 ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1);
1417 ldata->read_cnt += i;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418 cp += i;
1419 count -= i;
1420
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001421 i = min(N_TTY_BUF_SIZE - ldata->read_cnt,
1422 N_TTY_BUF_SIZE - ldata->read_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423 i = min(count, i);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001424 memcpy(ldata->read_buf + ldata->read_head, cp, i);
1425 ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1);
1426 ldata->read_cnt += i;
Ivo Sieben98001212013-01-28 13:32:01 +01001427 raw_spin_unlock_irqrestore(&ldata->read_lock, cpuflags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001428 } else {
Alan Cox4edf1822008-02-08 04:18:44 -08001429 for (i = count, p = cp, f = fp; i; i--, p++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430 if (f)
1431 flags = *f++;
1432 switch (flags) {
1433 case TTY_NORMAL:
1434 n_tty_receive_char(tty, *p);
1435 break;
1436 case TTY_BREAK:
1437 n_tty_receive_break(tty);
1438 break;
1439 case TTY_PARITY:
1440 case TTY_FRAME:
1441 n_tty_receive_parity_error(tty, *p);
1442 break;
1443 case TTY_OVERRUN:
1444 n_tty_receive_overrun(tty);
1445 break;
1446 default:
Alan Cox4edf1822008-02-08 04:18:44 -08001447 printk(KERN_ERR "%s: unknown flag %d\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001448 tty_name(tty, buf), flags);
1449 break;
1450 }
1451 }
Alan Coxf34d7a52008-04-30 00:54:13 -07001452 if (tty->ops->flush_chars)
1453 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001454 }
1455
Linus Torvalds55db4c62011-06-04 06:33:24 +09001456 n_tty_set_room(tty);
1457
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001458 if ((!ldata->icanon && (ldata->read_cnt >= tty->minimum_to_wake)) ||
hyc@symas.com26df6d12010-06-22 10:14:49 -07001459 L_EXTPROC(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
1461 if (waitqueue_active(&tty->read_wait))
1462 wake_up_interruptible(&tty->read_wait);
1463 }
1464
1465 /*
1466 * Check the remaining room for the input canonicalization
1467 * mode. We don't want to throttle the driver if we're in
1468 * canonical mode and don't have a newline yet!
1469 */
Peter Hurleye91e52e2013-03-06 08:20:53 -05001470 while (1) {
1471 tty_set_flow_change(tty, TTY_THROTTLE_SAFE);
1472 if (tty->receive_room >= TTY_THRESHOLD_THROTTLE)
1473 break;
1474 if (!tty_throttle_safe(tty))
1475 break;
1476 }
1477 __tty_set_flow_change(tty, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001478}
1479
1480int is_ignored(int sig)
1481{
1482 return (sigismember(&current->blocked, sig) ||
Alan Cox4edf1822008-02-08 04:18:44 -08001483 current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484}
1485
1486/**
1487 * n_tty_set_termios - termios data changed
1488 * @tty: terminal
1489 * @old: previous data
1490 *
1491 * Called by the tty layer when the user changes termios flags so
1492 * that the line discipline can plan ahead. This function cannot sleep
Alan Cox4edf1822008-02-08 04:18:44 -08001493 * and is protected from re-entry by the tty layer. The user is
Linus Torvalds1da177e2005-04-16 15:20:36 -07001494 * guaranteed that this function will not be re-entered or in progress
1495 * when the ldisc is closed.
Alan Cox17b82062008-10-13 10:45:06 +01001496 *
1497 * Locking: Caller holds tty->termios_mutex
Linus Torvalds1da177e2005-04-16 15:20:36 -07001498 */
Alan Cox4edf1822008-02-08 04:18:44 -08001499
1500static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001501{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001502 struct n_tty_data *ldata = tty->disc_data;
Alan Cox47afa7a2008-10-13 10:44:17 +01001503 int canon_change = 1;
Alan Cox47afa7a2008-10-13 10:44:17 +01001504
1505 if (old)
Alan Coxadc8d742012-07-14 15:31:47 +01001506 canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON;
Alan Cox47afa7a2008-10-13 10:44:17 +01001507 if (canon_change) {
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001508 bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001509 ldata->canon_head = ldata->read_tail;
1510 ldata->canon_data = 0;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001511 ldata->erasing = 0;
Alan Cox47afa7a2008-10-13 10:44:17 +01001512 }
1513
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001514 if (canon_change && !L_ICANON(tty) && ldata->read_cnt)
Alan Cox47afa7a2008-10-13 10:44:17 +01001515 wake_up_interruptible(&tty->read_wait);
Alan Cox4edf1822008-02-08 04:18:44 -08001516
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001517 ldata->icanon = (L_ICANON(tty) != 0);
Peter Hurley582f5592013-05-17 12:49:48 -04001518
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519 if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
1520 I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
1521 I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
1522 I_PARMRK(tty)) {
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001523 bitmap_zero(ldata->process_char_map, 256);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001524
1525 if (I_IGNCR(tty) || I_ICRNL(tty))
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001526 set_bit('\r', ldata->process_char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527 if (I_INLCR(tty))
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001528 set_bit('\n', ldata->process_char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001529
1530 if (L_ICANON(tty)) {
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001531 set_bit(ERASE_CHAR(tty), ldata->process_char_map);
1532 set_bit(KILL_CHAR(tty), ldata->process_char_map);
1533 set_bit(EOF_CHAR(tty), ldata->process_char_map);
1534 set_bit('\n', ldata->process_char_map);
1535 set_bit(EOL_CHAR(tty), ldata->process_char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 if (L_IEXTEN(tty)) {
1537 set_bit(WERASE_CHAR(tty),
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001538 ldata->process_char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001539 set_bit(LNEXT_CHAR(tty),
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001540 ldata->process_char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001541 set_bit(EOL2_CHAR(tty),
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001542 ldata->process_char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001543 if (L_ECHO(tty))
1544 set_bit(REPRINT_CHAR(tty),
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001545 ldata->process_char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001546 }
1547 }
1548 if (I_IXON(tty)) {
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001549 set_bit(START_CHAR(tty), ldata->process_char_map);
1550 set_bit(STOP_CHAR(tty), ldata->process_char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001551 }
1552 if (L_ISIG(tty)) {
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001553 set_bit(INTR_CHAR(tty), ldata->process_char_map);
1554 set_bit(QUIT_CHAR(tty), ldata->process_char_map);
1555 set_bit(SUSP_CHAR(tty), ldata->process_char_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001556 }
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001557 clear_bit(__DISABLED_CHAR, ldata->process_char_map);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001558 ldata->raw = 0;
1559 ldata->real_raw = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001560 } else {
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001561 ldata->raw = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001562 if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
1563 (I_IGNPAR(tty) || !I_INPCK(tty)) &&
1564 (tty->driver->flags & TTY_DRIVER_REAL_RAW))
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001565 ldata->real_raw = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566 else
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001567 ldata->real_raw = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001568 }
Linus Torvalds55db4c62011-06-04 06:33:24 +09001569 n_tty_set_room(tty);
Alan Coxf34d7a52008-04-30 00:54:13 -07001570 /* The termios change make the tty ready for I/O */
1571 wake_up_interruptible(&tty->write_wait);
1572 wake_up_interruptible(&tty->read_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573}
1574
1575/**
1576 * n_tty_close - close the ldisc for this tty
1577 * @tty: device
1578 *
Alan Cox4edf1822008-02-08 04:18:44 -08001579 * Called from the terminal layer when this line discipline is
1580 * being shut down, either because of a close or becsuse of a
Linus Torvalds1da177e2005-04-16 15:20:36 -07001581 * discipline change. The function will not be called while other
1582 * ldisc methods are in progress.
1583 */
Alan Cox4edf1822008-02-08 04:18:44 -08001584
Linus Torvalds1da177e2005-04-16 15:20:36 -07001585static void n_tty_close(struct tty_struct *tty)
1586{
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001587 struct n_tty_data *ldata = tty->disc_data;
1588
Peter Hurley79901312013-03-11 16:44:23 -04001589 if (tty->link)
1590 n_tty_packet_mode_flush(tty);
1591
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001592 kfree(ldata->read_buf);
1593 kfree(ldata->echo_buf);
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001594 kfree(ldata);
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001595 tty->disc_data = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001596}
1597
1598/**
1599 * n_tty_open - open an ldisc
1600 * @tty: terminal to open
1601 *
Alan Cox4edf1822008-02-08 04:18:44 -08001602 * Called when this line discipline is being attached to the
Linus Torvalds1da177e2005-04-16 15:20:36 -07001603 * terminal device. Can sleep. Called serialized so that no
1604 * other events will occur in parallel. No further open will occur
1605 * until a close.
1606 */
1607
1608static int n_tty_open(struct tty_struct *tty)
1609{
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001610 struct n_tty_data *ldata;
1611
1612 ldata = kzalloc(sizeof(*ldata), GFP_KERNEL);
1613 if (!ldata)
1614 goto err;
1615
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001616 ldata->overrun_time = jiffies;
Jiri Slabybddc7152012-10-18 22:26:42 +02001617 mutex_init(&ldata->atomic_read_lock);
1618 mutex_init(&ldata->output_lock);
1619 mutex_init(&ldata->echo_lock);
Ivo Sieben98001212013-01-28 13:32:01 +01001620 raw_spin_lock_init(&ldata->read_lock);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001621
Joe Petersona88a69c2009-01-02 13:40:53 +00001622 /* These are ugly. Currently a malloc failure here can panic */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001623 ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
1624 ldata->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
1625 if (!ldata->read_buf || !ldata->echo_buf)
Jiri Slabyb91939f2012-10-18 22:26:35 +02001626 goto err_free_bufs;
Alan Cox0b4068a2009-06-11 13:05:49 +01001627
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001628 tty->disc_data = ldata;
Peter Hurleyb66f4fa2013-03-11 16:44:32 -04001629 reset_buffer_flags(tty->disc_data);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001630 ldata->column = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631 tty->minimum_to_wake = 1;
1632 tty->closing = 0;
Peter Hurleyb66f4fa2013-03-11 16:44:32 -04001633 /* indicate buffer work may resume */
1634 clear_bit(TTY_LDISC_HALTED, &tty->flags);
1635 n_tty_set_termios(tty, NULL);
1636 tty_unthrottle(tty);
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001637
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638 return 0;
Jiri Slabyb91939f2012-10-18 22:26:35 +02001639err_free_bufs:
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001640 kfree(ldata->read_buf);
1641 kfree(ldata->echo_buf);
Jiri Slaby70ece7a2012-10-18 22:26:38 +02001642 kfree(ldata);
1643err:
Jiri Slabyb91939f2012-10-18 22:26:35 +02001644 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001645}
1646
1647static inline int input_available_p(struct tty_struct *tty, int amt)
1648{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001649 struct n_tty_data *ldata = tty->disc_data;
1650
OGAWA Hirofumie043e422009-07-29 12:15:56 -07001651 tty_flush_to_ldisc(tty);
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001652 if (ldata->icanon && !L_EXTPROC(tty)) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001653 if (ldata->canon_data)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001654 return 1;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001655 } else if (ldata->read_cnt >= (amt ? amt : 1))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001656 return 1;
1657
1658 return 0;
1659}
1660
1661/**
Thorsten Wißmannbbd20752011-12-08 17:47:33 +01001662 * copy_from_read_buf - copy read data directly
Linus Torvalds1da177e2005-04-16 15:20:36 -07001663 * @tty: terminal device
1664 * @b: user data
1665 * @nr: size of data
1666 *
Alan Cox11a96d12008-10-13 10:46:24 +01001667 * Helper function to speed up n_tty_read. It is only called when
Linus Torvalds1da177e2005-04-16 15:20:36 -07001668 * ICANON is off; it copies characters straight from the tty queue to
1669 * user space directly. It can be profitably called twice; once to
1670 * drain the space from the tail pointer to the (physical) end of the
1671 * buffer, and once to drain the space from the (physical) beginning of
1672 * the buffer to head pointer.
1673 *
Jiri Slabybddc7152012-10-18 22:26:42 +02001674 * Called under the ldata->atomic_read_lock sem
Linus Torvalds1da177e2005-04-16 15:20:36 -07001675 *
1676 */
Alan Cox4edf1822008-02-08 04:18:44 -08001677
Alan Cox33f0f882006-01-09 20:54:13 -08001678static int copy_from_read_buf(struct tty_struct *tty,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001679 unsigned char __user **b,
1680 size_t *nr)
1681
1682{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001683 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684 int retval;
1685 size_t n;
1686 unsigned long flags;
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02001687 bool is_eof;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001688
1689 retval = 0;
Ivo Sieben98001212013-01-28 13:32:01 +01001690 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001691 n = min(ldata->read_cnt, N_TTY_BUF_SIZE - ldata->read_tail);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001692 n = min(*nr, n);
Ivo Sieben98001212013-01-28 13:32:01 +01001693 raw_spin_unlock_irqrestore(&ldata->read_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694 if (n) {
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001695 retval = copy_to_user(*b, &ldata->read_buf[ldata->read_tail], n);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001696 n -= retval;
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02001697 is_eof = n == 1 &&
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001698 ldata->read_buf[ldata->read_tail] == EOF_CHAR(tty);
1699 tty_audit_add_data(tty, &ldata->read_buf[ldata->read_tail], n,
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001700 ldata->icanon);
Ivo Sieben98001212013-01-28 13:32:01 +01001701 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001702 ldata->read_tail = (ldata->read_tail + n) & (N_TTY_BUF_SIZE-1);
1703 ldata->read_cnt -= n;
hyc@symas.com26df6d12010-06-22 10:14:49 -07001704 /* Turn single EOF into zero-length read */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001705 if (L_EXTPROC(tty) && ldata->icanon && is_eof && !ldata->read_cnt)
Jiri Slaby3fa10cc2012-04-26 20:13:00 +02001706 n = 0;
Ivo Sieben98001212013-01-28 13:32:01 +01001707 raw_spin_unlock_irqrestore(&ldata->read_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001708 *b += n;
1709 *nr -= n;
1710 }
1711 return retval;
1712}
1713
Al Virocc4191d2008-03-29 03:08:48 +00001714extern ssize_t redirected_tty_write(struct file *, const char __user *,
Alan Cox4edf1822008-02-08 04:18:44 -08001715 size_t, loff_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001716
1717/**
1718 * job_control - check job control
1719 * @tty: tty
1720 * @file: file handle
1721 *
1722 * Perform job control management checks on this file/tty descriptor
Alan Cox4edf1822008-02-08 04:18:44 -08001723 * and if appropriate send any needed signals and return a negative
Linus Torvalds1da177e2005-04-16 15:20:36 -07001724 * error code if action should be taken.
Alan Cox04f378b2008-04-30 00:53:29 -07001725 *
Peter Hurley01a5e442013-03-06 08:38:20 -05001726 * Locking: redirected write test is safe
1727 * current->signal->tty check is safe
1728 * ctrl_lock to safely reference tty->pgrp
Linus Torvalds1da177e2005-04-16 15:20:36 -07001729 */
Alan Cox4edf1822008-02-08 04:18:44 -08001730
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731static int job_control(struct tty_struct *tty, struct file *file)
1732{
1733 /* Job control check -- must be done at start and after
1734 every sleep (POSIX.1 7.1.1.4). */
1735 /* NOTE: not yet done after every sleep pending a thorough
1736 check of the logic of this change. -- jlc */
1737 /* don't stop on /dev/console */
Peter Hurley01a5e442013-03-06 08:38:20 -05001738 if (file->f_op->write == redirected_tty_write ||
1739 current->signal->tty != tty)
1740 return 0;
1741
1742 spin_lock_irq(&tty->ctrl_lock);
1743 if (!tty->pgrp)
1744 printk(KERN_ERR "n_tty_read: no tty->pgrp!\n");
1745 else if (task_pgrp(current) != tty->pgrp) {
1746 spin_unlock_irq(&tty->ctrl_lock);
1747 if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned())
1748 return -EIO;
1749 kill_pgrp(task_pgrp(current), SIGTTIN, 1);
1750 set_thread_flag(TIF_SIGPENDING);
1751 return -ERESTARTSYS;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001752 }
Peter Hurley01a5e442013-03-06 08:38:20 -05001753 spin_unlock_irq(&tty->ctrl_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754 return 0;
1755}
Alan Cox4edf1822008-02-08 04:18:44 -08001756
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757
1758/**
Alan Cox11a96d12008-10-13 10:46:24 +01001759 * n_tty_read - read function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07001760 * @tty: tty device
1761 * @file: file object
1762 * @buf: userspace buffer pointer
1763 * @nr: size of I/O
1764 *
1765 * Perform reads for the line discipline. We are guaranteed that the
1766 * line discipline will not be closed under us but we may get multiple
1767 * parallel readers and must handle this ourselves. We may also get
1768 * a hangup. Always called in user context, may sleep.
1769 *
1770 * This code must be sure never to sleep through a hangup.
1771 */
Alan Cox4edf1822008-02-08 04:18:44 -08001772
Alan Cox11a96d12008-10-13 10:46:24 +01001773static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001774 unsigned char __user *buf, size_t nr)
1775{
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001776 struct n_tty_data *ldata = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001777 unsigned char __user *b = buf;
1778 DECLARE_WAITQUEUE(wait, current);
1779 int c;
1780 int minimum, time;
1781 ssize_t retval = 0;
1782 ssize_t size;
1783 long timeout;
1784 unsigned long flags;
Alan Cox04f378b2008-04-30 00:53:29 -07001785 int packet;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786
1787do_it_again:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788 c = job_control(tty, file);
Alan Cox4edf1822008-02-08 04:18:44 -08001789 if (c < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001790 return c;
Alan Cox4edf1822008-02-08 04:18:44 -08001791
Linus Torvalds1da177e2005-04-16 15:20:36 -07001792 minimum = time = 0;
1793 timeout = MAX_SCHEDULE_TIMEOUT;
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001794 if (!ldata->icanon) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795 time = (HZ / 10) * TIME_CHAR(tty);
1796 minimum = MIN_CHAR(tty);
1797 if (minimum) {
1798 if (time)
1799 tty->minimum_to_wake = 1;
1800 else if (!waitqueue_active(&tty->read_wait) ||
1801 (tty->minimum_to_wake > minimum))
1802 tty->minimum_to_wake = minimum;
1803 } else {
1804 timeout = 0;
1805 if (time) {
1806 timeout = time;
1807 time = 0;
1808 }
1809 tty->minimum_to_wake = minimum = 1;
1810 }
1811 }
1812
1813 /*
1814 * Internal serialization of reads.
1815 */
1816 if (file->f_flags & O_NONBLOCK) {
Jiri Slabybddc7152012-10-18 22:26:42 +02001817 if (!mutex_trylock(&ldata->atomic_read_lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001818 return -EAGAIN;
Alan Cox4edf1822008-02-08 04:18:44 -08001819 } else {
Jiri Slabybddc7152012-10-18 22:26:42 +02001820 if (mutex_lock_interruptible(&ldata->atomic_read_lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001821 return -ERESTARTSYS;
1822 }
Alan Cox04f378b2008-04-30 00:53:29 -07001823 packet = tty->packet;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824
1825 add_wait_queue(&tty->read_wait, &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826 while (nr) {
1827 /* First test for status change. */
Alan Cox04f378b2008-04-30 00:53:29 -07001828 if (packet && tty->link->ctrl_status) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829 unsigned char cs;
1830 if (b != buf)
1831 break;
Alan Cox04f378b2008-04-30 00:53:29 -07001832 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001833 cs = tty->link->ctrl_status;
1834 tty->link->ctrl_status = 0;
Alan Cox04f378b2008-04-30 00:53:29 -07001835 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
Miloslav Trmac522ed772007-07-15 23:40:56 -07001836 if (tty_put_user(tty, cs, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001837 retval = -EFAULT;
1838 b--;
1839 break;
1840 }
1841 nr--;
1842 break;
1843 }
1844 /* This statement must be first before checking for input
1845 so that any interrupt will set the state back to
1846 TASK_RUNNING. */
1847 set_current_state(TASK_INTERRUPTIBLE);
Alan Cox4edf1822008-02-08 04:18:44 -08001848
Linus Torvalds1da177e2005-04-16 15:20:36 -07001849 if (((minimum - (b - buf)) < tty->minimum_to_wake) &&
1850 ((minimum - (b - buf)) >= 1))
1851 tty->minimum_to_wake = (minimum - (b - buf));
Alan Cox4edf1822008-02-08 04:18:44 -08001852
Linus Torvalds1da177e2005-04-16 15:20:36 -07001853 if (!input_available_p(tty, 0)) {
1854 if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
1855 retval = -EIO;
1856 break;
1857 }
1858 if (tty_hung_up_p(file))
1859 break;
1860 if (!timeout)
1861 break;
1862 if (file->f_flags & O_NONBLOCK) {
1863 retval = -EAGAIN;
1864 break;
1865 }
1866 if (signal_pending(current)) {
1867 retval = -ERESTARTSYS;
1868 break;
1869 }
Linus Torvalds55db4c62011-06-04 06:33:24 +09001870 /* FIXME: does n_tty_set_room need locking ? */
1871 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001872 timeout = schedule_timeout(timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001873 continue;
1874 }
1875 __set_current_state(TASK_RUNNING);
1876
1877 /* Deal with packet mode. */
Alan Cox04f378b2008-04-30 00:53:29 -07001878 if (packet && b == buf) {
Miloslav Trmac522ed772007-07-15 23:40:56 -07001879 if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880 retval = -EFAULT;
1881 b--;
1882 break;
1883 }
1884 nr--;
1885 }
1886
Jiri Slaby53c5ee22012-10-18 22:26:39 +02001887 if (ldata->icanon && !L_EXTPROC(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888 /* N.B. avoid overrun if nr == 0 */
Ivo Sieben98001212013-01-28 13:32:01 +01001889 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001890 while (nr && ldata->read_cnt) {
Alan Cox4edf1822008-02-08 04:18:44 -08001891 int eol;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001892
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001893 eol = test_and_clear_bit(ldata->read_tail,
Jiri Slaby3fe780b2012-10-18 22:26:40 +02001894 ldata->read_flags);
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001895 c = ldata->read_buf[ldata->read_tail];
1896 ldata->read_tail = ((ldata->read_tail+1) &
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897 (N_TTY_BUF_SIZE-1));
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001898 ldata->read_cnt--;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001899 if (eol) {
1900 /* this test should be redundant:
1901 * we shouldn't be reading data if
1902 * canon_data is 0
1903 */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02001904 if (--ldata->canon_data < 0)
1905 ldata->canon_data = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001906 }
Ivo Sieben98001212013-01-28 13:32:01 +01001907 raw_spin_unlock_irqrestore(&ldata->read_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908
1909 if (!eol || (c != __DISABLED_CHAR)) {
Miloslav Trmac522ed772007-07-15 23:40:56 -07001910 if (tty_put_user(tty, c, b++)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001911 retval = -EFAULT;
1912 b--;
Ivo Sieben98001212013-01-28 13:32:01 +01001913 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914 break;
1915 }
1916 nr--;
1917 }
Miloslav Trmac522ed772007-07-15 23:40:56 -07001918 if (eol) {
1919 tty_audit_push(tty);
Ivo Sieben98001212013-01-28 13:32:01 +01001920 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001921 break;
Miloslav Trmac522ed772007-07-15 23:40:56 -07001922 }
Ivo Sieben98001212013-01-28 13:32:01 +01001923 raw_spin_lock_irqsave(&ldata->read_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001924 }
Ivo Sieben98001212013-01-28 13:32:01 +01001925 raw_spin_unlock_irqrestore(&ldata->read_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001926 if (retval)
1927 break;
1928 } else {
1929 int uncopied;
Alan Cox04f378b2008-04-30 00:53:29 -07001930 /* The copy function takes the read lock and handles
1931 locking internally for this case */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001932 uncopied = copy_from_read_buf(tty, &b, &nr);
1933 uncopied += copy_from_read_buf(tty, &b, &nr);
1934 if (uncopied) {
1935 retval = -EFAULT;
1936 break;
1937 }
1938 }
1939
1940 /* If there is enough space in the read buffer now, let the
1941 * low-level driver know. We use n_tty_chars_in_buffer() to
1942 * check the buffer, as it now knows about canonical mode.
1943 * Otherwise, if the driver is throttled and the line is
1944 * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
1945 * we won't get any more characters.
1946 */
Peter Hurleye91e52e2013-03-06 08:20:53 -05001947 while (1) {
1948 tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE);
1949 if (n_tty_chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
1950 break;
1951 if (!tty->count)
1952 break;
Linus Torvalds55db4c62011-06-04 06:33:24 +09001953 n_tty_set_room(tty);
Peter Hurleye91e52e2013-03-06 08:20:53 -05001954 if (!tty_unthrottle_safe(tty))
1955 break;
Linus Torvalds55db4c62011-06-04 06:33:24 +09001956 }
Peter Hurleye91e52e2013-03-06 08:20:53 -05001957 __tty_set_flow_change(tty, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958
1959 if (b - buf >= minimum)
1960 break;
1961 if (time)
1962 timeout = time;
1963 }
Jiri Slabybddc7152012-10-18 22:26:42 +02001964 mutex_unlock(&ldata->atomic_read_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001965 remove_wait_queue(&tty->read_wait, &wait);
1966
1967 if (!waitqueue_active(&tty->read_wait))
1968 tty->minimum_to_wake = minimum;
1969
1970 __set_current_state(TASK_RUNNING);
1971 size = b - buf;
1972 if (size) {
1973 retval = size;
1974 if (nr)
Alan Cox4edf1822008-02-08 04:18:44 -08001975 clear_bit(TTY_PUSH, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001976 } else if (test_and_clear_bit(TTY_PUSH, &tty->flags))
Thorsten Wißmannbbd20752011-12-08 17:47:33 +01001977 goto do_it_again;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978
Linus Torvalds55db4c62011-06-04 06:33:24 +09001979 n_tty_set_room(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001980 return retval;
1981}
1982
1983/**
Alan Cox11a96d12008-10-13 10:46:24 +01001984 * n_tty_write - write function for tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07001985 * @tty: tty device
1986 * @file: file object
1987 * @buf: userspace buffer pointer
1988 * @nr: size of I/O
1989 *
Joe Petersona88a69c2009-01-02 13:40:53 +00001990 * Write function of the terminal device. This is serialized with
Linus Torvalds1da177e2005-04-16 15:20:36 -07001991 * respect to other write callers but not to termios changes, reads
Joe Petersona88a69c2009-01-02 13:40:53 +00001992 * and other such events. Since the receive code will echo characters,
1993 * thus calling driver write methods, the output_lock is used in
1994 * the output processing functions called here as well as in the
1995 * echo processing function to protect the column state and space
1996 * left in the buffer.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001997 *
1998 * This code must be sure never to sleep through a hangup.
Joe Petersona88a69c2009-01-02 13:40:53 +00001999 *
2000 * Locking: output_lock to protect column state and space left
2001 * (note that the process_output*() functions take this
2002 * lock themselves)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003 */
Alan Cox4edf1822008-02-08 04:18:44 -08002004
Alan Cox11a96d12008-10-13 10:46:24 +01002005static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
Joe Petersona88a69c2009-01-02 13:40:53 +00002006 const unsigned char *buf, size_t nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002007{
2008 const unsigned char *b = buf;
2009 DECLARE_WAITQUEUE(wait, current);
2010 int c;
2011 ssize_t retval = 0;
2012
2013 /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
2014 if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) {
2015 retval = tty_check_change(tty);
2016 if (retval)
2017 return retval;
2018 }
2019
Joe Petersona88a69c2009-01-02 13:40:53 +00002020 /* Write out any echoed characters that are still pending */
2021 process_echoes(tty);
Alan Cox300a6202009-01-02 13:41:04 +00002022
Linus Torvalds1da177e2005-04-16 15:20:36 -07002023 add_wait_queue(&tty->write_wait, &wait);
2024 while (1) {
2025 set_current_state(TASK_INTERRUPTIBLE);
2026 if (signal_pending(current)) {
2027 retval = -ERESTARTSYS;
2028 break;
2029 }
2030 if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) {
2031 retval = -EIO;
2032 break;
2033 }
Peter Hurley582f5592013-05-17 12:49:48 -04002034 if (O_OPOST(tty)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002035 while (nr > 0) {
Joe Petersona88a69c2009-01-02 13:40:53 +00002036 ssize_t num = process_output_block(tty, b, nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002037 if (num < 0) {
2038 if (num == -EAGAIN)
2039 break;
2040 retval = num;
2041 goto break_out;
2042 }
2043 b += num;
2044 nr -= num;
2045 if (nr == 0)
2046 break;
2047 c = *b;
Joe Petersona88a69c2009-01-02 13:40:53 +00002048 if (process_output(c, tty) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002049 break;
2050 b++; nr--;
2051 }
Alan Coxf34d7a52008-04-30 00:54:13 -07002052 if (tty->ops->flush_chars)
2053 tty->ops->flush_chars(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002054 } else {
Roman Zippeld6afe272005-07-07 17:56:55 -07002055 while (nr > 0) {
Alan Coxf34d7a52008-04-30 00:54:13 -07002056 c = tty->ops->write(tty, b, nr);
Roman Zippeld6afe272005-07-07 17:56:55 -07002057 if (c < 0) {
2058 retval = c;
2059 goto break_out;
2060 }
2061 if (!c)
2062 break;
2063 b += c;
2064 nr -= c;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002065 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002066 }
2067 if (!nr)
2068 break;
2069 if (file->f_flags & O_NONBLOCK) {
2070 retval = -EAGAIN;
2071 break;
2072 }
2073 schedule();
2074 }
2075break_out:
2076 __set_current_state(TASK_RUNNING);
2077 remove_wait_queue(&tty->write_wait, &wait);
Thomas Pfaffff8cb0f2009-01-02 13:47:13 +00002078 if (b - buf != nr && tty->fasync)
2079 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002080 return (b - buf) ? b - buf : retval;
2081}
2082
2083/**
Alan Cox11a96d12008-10-13 10:46:24 +01002084 * n_tty_poll - poll method for N_TTY
Linus Torvalds1da177e2005-04-16 15:20:36 -07002085 * @tty: terminal device
2086 * @file: file accessing it
2087 * @wait: poll table
2088 *
2089 * Called when the line discipline is asked to poll() for data or
2090 * for special events. This code is not serialized with respect to
2091 * other events save open/close.
2092 *
2093 * This code must be sure never to sleep through a hangup.
2094 * Called without the kernel lock held - fine
Linus Torvalds1da177e2005-04-16 15:20:36 -07002095 */
Alan Cox4edf1822008-02-08 04:18:44 -08002096
Alan Cox11a96d12008-10-13 10:46:24 +01002097static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
Alan Cox4edf1822008-02-08 04:18:44 -08002098 poll_table *wait)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002099{
2100 unsigned int mask = 0;
2101
2102 poll_wait(file, &tty->read_wait, wait);
2103 poll_wait(file, &tty->write_wait, wait);
2104 if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty)))
2105 mask |= POLLIN | POLLRDNORM;
2106 if (tty->packet && tty->link->ctrl_status)
2107 mask |= POLLPRI | POLLIN | POLLRDNORM;
2108 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
2109 mask |= POLLHUP;
2110 if (tty_hung_up_p(file))
2111 mask |= POLLHUP;
2112 if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) {
2113 if (MIN_CHAR(tty) && !TIME_CHAR(tty))
2114 tty->minimum_to_wake = MIN_CHAR(tty);
2115 else
2116 tty->minimum_to_wake = 1;
2117 }
Alan Coxf34d7a52008-04-30 00:54:13 -07002118 if (tty->ops->write && !tty_is_writelocked(tty) &&
2119 tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
2120 tty_write_room(tty) > 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002121 mask |= POLLOUT | POLLWRNORM;
2122 return mask;
2123}
2124
Jiri Slaby57c94122012-10-18 22:26:43 +02002125static unsigned long inq_canon(struct n_tty_data *ldata)
Alan Cox47afa7a2008-10-13 10:44:17 +01002126{
2127 int nr, head, tail;
2128
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002129 if (!ldata->canon_data)
Alan Cox47afa7a2008-10-13 10:44:17 +01002130 return 0;
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002131 head = ldata->canon_head;
2132 tail = ldata->read_tail;
Alan Cox47afa7a2008-10-13 10:44:17 +01002133 nr = (head - tail) & (N_TTY_BUF_SIZE-1);
2134 /* Skip EOF-chars.. */
2135 while (head != tail) {
Jiri Slaby3fe780b2012-10-18 22:26:40 +02002136 if (test_bit(tail, ldata->read_flags) &&
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002137 ldata->read_buf[tail] == __DISABLED_CHAR)
Alan Cox47afa7a2008-10-13 10:44:17 +01002138 nr--;
2139 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
2140 }
2141 return nr;
2142}
2143
2144static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
2145 unsigned int cmd, unsigned long arg)
2146{
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002147 struct n_tty_data *ldata = tty->disc_data;
Alan Cox47afa7a2008-10-13 10:44:17 +01002148 int retval;
2149
2150 switch (cmd) {
2151 case TIOCOUTQ:
2152 return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
2153 case TIOCINQ:
Alan Cox17b82062008-10-13 10:45:06 +01002154 /* FIXME: Locking */
Jiri Slabyba2e68a2012-10-18 22:26:41 +02002155 retval = ldata->read_cnt;
Alan Cox47afa7a2008-10-13 10:44:17 +01002156 if (L_ICANON(tty))
Jiri Slaby57c94122012-10-18 22:26:43 +02002157 retval = inq_canon(ldata);
Alan Cox47afa7a2008-10-13 10:44:17 +01002158 return put_user(retval, (unsigned int __user *) arg);
2159 default:
2160 return n_tty_ioctl_helper(tty, file, cmd, arg);
2161 }
2162}
2163
Alan Coxa352def2008-07-16 21:53:12 +01002164struct tty_ldisc_ops tty_ldisc_N_TTY = {
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002165 .magic = TTY_LDISC_MAGIC,
2166 .name = "n_tty",
2167 .open = n_tty_open,
2168 .close = n_tty_close,
2169 .flush_buffer = n_tty_flush_buffer,
2170 .chars_in_buffer = n_tty_chars_in_buffer,
Alan Cox11a96d12008-10-13 10:46:24 +01002171 .read = n_tty_read,
2172 .write = n_tty_write,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002173 .ioctl = n_tty_ioctl,
2174 .set_termios = n_tty_set_termios,
Alan Cox11a96d12008-10-13 10:46:24 +01002175 .poll = n_tty_poll,
Paul Fulghume10cc1d2007-05-10 22:22:50 -07002176 .receive_buf = n_tty_receive_buf,
2177 .write_wakeup = n_tty_write_wakeup
Linus Torvalds1da177e2005-04-16 15:20:36 -07002178};
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -08002179
2180/**
2181 * n_tty_inherit_ops - inherit N_TTY methods
2182 * @ops: struct tty_ldisc_ops where to save N_TTY methods
2183 *
George Spelvin593fb1ae42013-02-12 02:00:43 -05002184 * Enables a 'subclass' line discipline to 'inherit' N_TTY
Rodolfo Giometti572b9ad2010-03-10 15:23:46 -08002185 * methods.
2186 */
2187
2188void n_tty_inherit_ops(struct tty_ldisc_ops *ops)
2189{
2190 *ops = tty_ldisc_N_TTY;
2191 ops->owner = NULL;
2192 ops->refcount = ops->flags = 0;
2193}
2194EXPORT_SYMBOL_GPL(n_tty_inherit_ops);