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Commit | Line | Data |
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e3b3d0f5 | 1 | // SPDX-License-Identifier: GPL-1.0+ |
1da177e4 LT |
2 | /* |
3 | * n_tty.c --- implements the N_TTY line discipline. | |
4edf1827 | 4 | * |
1da177e4 LT |
5 | * This code used to be in tty_io.c, but things are getting hairy |
6 | * enough that it made sense to split things off. (The N_TTY | |
7 | * processing has changed so much that it's hardly recognizable, | |
8 | * anyway...) | |
9 | * | |
10 | * Note that the open routine for N_TTY is guaranteed never to return | |
11 | * an error. This is because Linux will fall back to setting a line | |
4edf1827 | 12 | * to N_TTY if it can not switch to any other line discipline. |
1da177e4 LT |
13 | * |
14 | * Written by Theodore Ts'o, Copyright 1994. | |
4edf1827 | 15 | * |
1da177e4 LT |
16 | * This file also contains code originally written by Linus Torvalds, |
17 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. | |
4edf1827 | 18 | * |
1da177e4 LT |
19 | * Reduced memory usage for older ARM systems - Russell King. |
20 | * | |
4edf1827 | 21 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
1da177e4 LT |
22 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
23 | * who actually finally proved there really was a race. | |
24 | * | |
25 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to | |
26 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. | |
11a96d18 | 27 | * Also fixed a bug in BLOCKING mode where n_tty_write returns |
1da177e4 LT |
28 | * EAGAIN |
29 | */ | |
30 | ||
31 | #include <linux/types.h> | |
32 | #include <linux/major.h> | |
33 | #include <linux/errno.h> | |
34 | #include <linux/signal.h> | |
35 | #include <linux/fcntl.h> | |
36 | #include <linux/sched.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/tty.h> | |
39 | #include <linux/timer.h> | |
40 | #include <linux/ctype.h> | |
41 | #include <linux/mm.h> | |
42 | #include <linux/string.h> | |
43 | #include <linux/slab.h> | |
44 | #include <linux/poll.h> | |
45 | #include <linux/bitops.h> | |
522ed776 MT |
46 | #include <linux/audit.h> |
47 | #include <linux/file.h> | |
300a6204 | 48 | #include <linux/uaccess.h> |
572b9adb | 49 | #include <linux/module.h> |
593fb1ae | 50 | #include <linux/ratelimit.h> |
86e35aea | 51 | #include <linux/vmalloc.h> |
1da177e4 | 52 | |
1da177e4 LT |
53 | |
54 | /* number of characters left in xmit buffer before select has we have room */ | |
55 | #define WAKEUP_CHARS 256 | |
56 | ||
57 | /* | |
58 | * This defines the low- and high-watermarks for throttling and | |
59 | * unthrottling the TTY driver. These watermarks are used for | |
60 | * controlling the space in the read buffer. | |
61 | */ | |
62 | #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ | |
bbd20759 | 63 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
1da177e4 | 64 | |
a88a69c9 JP |
65 | /* |
66 | * Special byte codes used in the echo buffer to represent operations | |
67 | * or special handling of characters. Bytes in the echo buffer that | |
68 | * are not part of such special blocks are treated as normal character | |
69 | * codes. | |
70 | */ | |
71 | #define ECHO_OP_START 0xff | |
72 | #define ECHO_OP_MOVE_BACK_COL 0x80 | |
73 | #define ECHO_OP_SET_CANON_COL 0x81 | |
74 | #define ECHO_OP_ERASE_TAB 0x82 | |
75 | ||
cbfd0340 PH |
76 | #define ECHO_COMMIT_WATERMARK 256 |
77 | #define ECHO_BLOCK 256 | |
78 | #define ECHO_DISCARD_WATERMARK N_TTY_BUF_SIZE - (ECHO_BLOCK + 32) | |
79 | ||
80 | ||
32f13521 PH |
81 | #undef N_TTY_TRACE |
82 | #ifdef N_TTY_TRACE | |
83 | # define n_tty_trace(f, args...) trace_printk(f, ##args) | |
84 | #else | |
85 | # define n_tty_trace(f, args...) | |
86 | #endif | |
87 | ||
70ece7a7 | 88 | struct n_tty_data { |
fb7aa03d PH |
89 | /* producer-published */ |
90 | size_t read_head; | |
70aca71f | 91 | size_t commit_head; |
fb7aa03d | 92 | size_t canon_head; |
9dfd16dd PH |
93 | size_t echo_head; |
94 | size_t echo_commit; | |
1075a6e2 | 95 | size_t echo_mark; |
1bb9d562 | 96 | DECLARE_BITMAP(char_map, 256); |
fb7aa03d PH |
97 | |
98 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c JS |
99 | unsigned long overrun_time; |
100 | int num_overrun; | |
101 | ||
24a89d1c PH |
102 | /* non-atomic */ |
103 | bool no_room; | |
104 | ||
fb7aa03d | 105 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c | 106 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
4d0ed182 | 107 | unsigned char push:1; |
3fe780b3 | 108 | |
fb7aa03d | 109 | /* shared by producer and consumer */ |
20bafb3d | 110 | char read_buf[N_TTY_BUF_SIZE]; |
3fe780b3 | 111 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
20bafb3d | 112 | unsigned char echo_buf[N_TTY_BUF_SIZE]; |
ba2e68ac | 113 | |
fb7aa03d PH |
114 | /* consumer-published */ |
115 | size_t read_tail; | |
40d5e090 | 116 | size_t line_start; |
fb7aa03d | 117 | |
fb7aa03d PH |
118 | /* protected by output lock */ |
119 | unsigned int column; | |
ba2e68ac | 120 | unsigned int canon_column; |
9dfd16dd | 121 | size_t echo_tail; |
bddc7152 JS |
122 | |
123 | struct mutex atomic_read_lock; | |
124 | struct mutex output_lock; | |
70ece7a7 JS |
125 | }; |
126 | ||
63891322 TH |
127 | #define MASK(x) ((x) & (N_TTY_BUF_SIZE - 1)) |
128 | ||
ce74117a PH |
129 | static inline size_t read_cnt(struct n_tty_data *ldata) |
130 | { | |
a2f73be8 | 131 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
132 | } |
133 | ||
bc5a5e3f PH |
134 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
135 | { | |
136 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
137 | } | |
138 | ||
139 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
140 | { | |
141 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
142 | } | |
143 | ||
addaebcc PH |
144 | static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) |
145 | { | |
146 | return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
147 | } | |
148 | ||
149 | static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) | |
150 | { | |
151 | return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
152 | } | |
153 | ||
679e7c29 PH |
154 | static int tty_copy_to_user(struct tty_struct *tty, void __user *to, |
155 | size_t tail, size_t n) | |
72586c60 LA |
156 | { |
157 | struct n_tty_data *ldata = tty->disc_data; | |
679e7c29 PH |
158 | size_t size = N_TTY_BUF_SIZE - tail; |
159 | const void *from = read_buf_addr(ldata, tail); | |
160 | int uncopied; | |
161 | ||
162 | if (n > size) { | |
309426ae | 163 | tty_audit_add_data(tty, from, size); |
679e7c29 PH |
164 | uncopied = copy_to_user(to, from, size); |
165 | if (uncopied) | |
166 | return uncopied; | |
167 | to += size; | |
168 | n -= size; | |
169 | from = ldata->read_buf; | |
170 | } | |
72586c60 | 171 | |
309426ae | 172 | tty_audit_add_data(tty, from, n); |
72586c60 LA |
173 | return copy_to_user(to, from, n); |
174 | } | |
175 | ||
24a89d1c | 176 | /** |
2c5dc464 | 177 | * n_tty_kick_worker - start input worker (if required) |
24a89d1c PH |
178 | * @tty: terminal |
179 | * | |
2c5dc464 | 180 | * Re-schedules the flip buffer work if it may have stopped |
24a89d1c | 181 | * |
6d76bd26 PH |
182 | * Caller holds exclusive termios_rwsem |
183 | * or | |
184 | * n_tty_read()/consumer path: | |
185 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
186 | */ |
187 | ||
2c5dc464 | 188 | static void n_tty_kick_worker(struct tty_struct *tty) |
7879a9f9 | 189 | { |
24a89d1c PH |
190 | struct n_tty_data *ldata = tty->disc_data; |
191 | ||
2c5dc464 PH |
192 | /* Did the input worker stop? Restart it */ |
193 | if (unlikely(ldata->no_room)) { | |
24a89d1c PH |
194 | ldata->no_room = 0; |
195 | ||
ecbbfd44 | 196 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 197 | "scheduling with invalid itty\n"); |
21622939 PH |
198 | /* see if ldisc has been killed - if so, this means that |
199 | * even though the ldisc has been halted and ->buf.work | |
200 | * cancelled, ->buf.work is about to be rescheduled | |
201 | */ | |
202 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
203 | "scheduling buffer work for halted ldisc\n"); | |
e176058f | 204 | tty_buffer_restart_work(tty->port); |
ecbbfd44 | 205 | } |
55db4c64 LT |
206 | } |
207 | ||
9a4aec2d PH |
208 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
209 | { | |
210 | struct n_tty_data *ldata = tty->disc_data; | |
211 | ssize_t n = 0; | |
212 | ||
213 | if (!ldata->icanon) | |
70aca71f | 214 | n = ldata->commit_head - ldata->read_tail; |
9a4aec2d PH |
215 | else |
216 | n = ldata->canon_head - ldata->read_tail; | |
217 | return n; | |
218 | } | |
219 | ||
ee0bab83 PH |
220 | /** |
221 | * n_tty_write_wakeup - asynchronous I/O notifier | |
222 | * @tty: tty device | |
223 | * | |
224 | * Required for the ptys, serial driver etc. since processes | |
225 | * that attach themselves to the master and rely on ASYNC | |
226 | * IO must be woken up | |
227 | */ | |
228 | ||
229 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
230 | { | |
7bccc365 PH |
231 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
232 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
ee0bab83 PH |
233 | } |
234 | ||
4a23a4df | 235 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 236 | { |
a342846f PH |
237 | struct n_tty_data *ldata = tty->disc_data; |
238 | ||
6367ca72 PH |
239 | /* |
240 | * Check the remaining room for the input canonicalization | |
241 | * mode. We don't want to throttle the driver if we're in | |
242 | * canonical mode and don't have a newline yet! | |
243 | */ | |
a342846f PH |
244 | if (ldata->icanon && ldata->canon_head == ldata->read_tail) |
245 | return; | |
246 | ||
6367ca72 PH |
247 | while (1) { |
248 | int throttled; | |
249 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
5e28cca1 | 250 | if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE) |
6367ca72 PH |
251 | break; |
252 | throttled = tty_throttle_safe(tty); | |
253 | if (!throttled) | |
254 | break; | |
255 | } | |
256 | __tty_set_flow_change(tty, 0); | |
257 | } | |
258 | ||
4b293492 | 259 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 260 | { |
6d27a63c | 261 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { |
3afb1b39 PH |
262 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) |
263 | return; | |
2c5dc464 | 264 | n_tty_kick_worker(tty); |
6d27a63c | 265 | tty_wakeup(tty->link); |
3afb1b39 PH |
266 | return; |
267 | } | |
268 | ||
6367ca72 PH |
269 | /* If there is enough space in the read buffer now, let the |
270 | * low-level driver know. We use chars_in_buffer() to | |
271 | * check the buffer, as it now knows about canonical mode. | |
272 | * Otherwise, if the driver is throttled and the line is | |
273 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
274 | * we won't get any more characters. | |
275 | */ | |
276 | ||
277 | while (1) { | |
278 | int unthrottled; | |
279 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
280 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
281 | break; | |
2c5dc464 | 282 | n_tty_kick_worker(tty); |
6367ca72 PH |
283 | unthrottled = tty_unthrottle_safe(tty); |
284 | if (!unthrottled) | |
285 | break; | |
286 | } | |
287 | __tty_set_flow_change(tty, 0); | |
288 | } | |
289 | ||
17b82060 AC |
290 | /** |
291 | * put_tty_queue - add character to tty | |
292 | * @c: character | |
57c94121 | 293 | * @ldata: n_tty data |
17b82060 | 294 | * |
6d76bd26 PH |
295 | * Add a character to the tty read_buf queue. |
296 | * | |
297 | * n_tty_receive_buf()/producer path: | |
298 | * caller holds non-exclusive termios_rwsem | |
17b82060 AC |
299 | */ |
300 | ||
19e2ad6a | 301 | static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 302 | { |
8bfbe2de CR |
303 | *read_buf_addr(ldata, ldata->read_head) = c; |
304 | ldata->read_head++; | |
1da177e4 LT |
305 | } |
306 | ||
1da177e4 LT |
307 | /** |
308 | * reset_buffer_flags - reset buffer state | |
309 | * @tty: terminal to reset | |
310 | * | |
25518c68 PH |
311 | * Reset the read buffer counters and clear the flags. |
312 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 313 | * |
6d76bd26 PH |
314 | * Locking: caller holds exclusive termios_rwsem |
315 | * (or locking is not required) | |
1da177e4 | 316 | */ |
a88a69c9 | 317 | |
b66f4fa5 | 318 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 319 | { |
a73d3d69 | 320 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 321 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
70aca71f | 322 | ldata->commit_head = 0; |
1075a6e2 | 323 | ldata->echo_mark = 0; |
40d5e090 | 324 | ldata->line_start = 0; |
a88a69c9 | 325 | |
a73d3d69 | 326 | ldata->erasing = 0; |
3fe780b3 | 327 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 | 328 | ldata->push = 0; |
1da177e4 LT |
329 | } |
330 | ||
a30737ab PH |
331 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
332 | { | |
333 | unsigned long flags; | |
334 | ||
a30737ab | 335 | if (tty->link->packet) { |
54e8e5fc | 336 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
a30737ab | 337 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; |
54e8e5fc | 338 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
e81107d4 | 339 | wake_up_interruptible(&tty->link->read_wait); |
a30737ab | 340 | } |
a30737ab PH |
341 | } |
342 | ||
1da177e4 LT |
343 | /** |
344 | * n_tty_flush_buffer - clean input queue | |
345 | * @tty: terminal device | |
346 | * | |
25518c68 PH |
347 | * Flush the input buffer. Called when the tty layer wants the |
348 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
349 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 350 | * |
6d76bd26 PH |
351 | * Holds termios_rwsem to exclude producer/consumer while |
352 | * buffer indices are reset. | |
353 | * | |
354 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 355 | */ |
4edf1827 AC |
356 | |
357 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 358 | { |
6d76bd26 | 359 | down_write(&tty->termios_rwsem); |
b66f4fa5 | 360 | reset_buffer_flags(tty->disc_data); |
2c5dc464 | 361 | n_tty_kick_worker(tty); |
4edf1827 | 362 | |
a30737ab PH |
363 | if (tty->link) |
364 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 365 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
366 | } |
367 | ||
1da177e4 LT |
368 | /** |
369 | * is_utf8_continuation - utf8 multibyte check | |
370 | * @c: byte to check | |
371 | * | |
372 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
373 | * character. We use this to correctly compute the on screen size | |
374 | * of the character when printing | |
375 | */ | |
4edf1827 | 376 | |
1da177e4 LT |
377 | static inline int is_utf8_continuation(unsigned char c) |
378 | { | |
379 | return (c & 0xc0) == 0x80; | |
380 | } | |
381 | ||
382 | /** | |
383 | * is_continuation - multibyte check | |
384 | * @c: byte to check | |
385 | * | |
386 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
387 | * character and the terminal is in unicode mode. | |
388 | */ | |
4edf1827 | 389 | |
1da177e4 LT |
390 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
391 | { | |
392 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
393 | } | |
394 | ||
395 | /** | |
a88a69c9 | 396 | * do_output_char - output one character |
1da177e4 LT |
397 | * @c: character (or partial unicode symbol) |
398 | * @tty: terminal device | |
a88a69c9 | 399 | * @space: space available in tty driver write buffer |
1da177e4 | 400 | * |
a88a69c9 JP |
401 | * This is a helper function that handles one output character |
402 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
403 | * doing OPOST processing and putting the results in the |
404 | * tty driver's write buffer. | |
a88a69c9 JP |
405 | * |
406 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
407 | * and NLDLY. They simply aren't relevant in the world today. | |
408 | * If you ever need them, add them here. | |
1da177e4 | 409 | * |
a88a69c9 JP |
410 | * Returns the number of bytes of buffer space used or -1 if |
411 | * no space left. | |
412 | * | |
413 | * Locking: should be called under the output_lock to protect | |
414 | * the column state and space left in the buffer | |
1da177e4 | 415 | */ |
4edf1827 | 416 | |
a88a69c9 | 417 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 418 | { |
53c5ee2c | 419 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 420 | int spaces; |
1da177e4 | 421 | |
1da177e4 LT |
422 | if (!space) |
423 | return -1; | |
300a6204 | 424 | |
a88a69c9 JP |
425 | switch (c) { |
426 | case '\n': | |
427 | if (O_ONLRET(tty)) | |
53c5ee2c | 428 | ldata->column = 0; |
a88a69c9 JP |
429 | if (O_ONLCR(tty)) { |
430 | if (space < 2) | |
431 | return -1; | |
ba2e68ac | 432 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 433 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
434 | return 2; |
435 | } | |
ba2e68ac | 436 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
437 | break; |
438 | case '\r': | |
53c5ee2c | 439 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
440 | return 0; |
441 | if (O_OCRNL(tty)) { | |
442 | c = '\n'; | |
443 | if (O_ONLRET(tty)) | |
ba2e68ac | 444 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 445 | break; |
a88a69c9 | 446 | } |
ba2e68ac | 447 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
448 | break; |
449 | case '\t': | |
53c5ee2c | 450 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
451 | if (O_TABDLY(tty) == XTABS) { |
452 | if (space < spaces) | |
453 | return -1; | |
53c5ee2c | 454 | ldata->column += spaces; |
a88a69c9 JP |
455 | tty->ops->write(tty, " ", spaces); |
456 | return spaces; | |
1da177e4 | 457 | } |
53c5ee2c | 458 | ldata->column += spaces; |
a88a69c9 JP |
459 | break; |
460 | case '\b': | |
53c5ee2c JS |
461 | if (ldata->column > 0) |
462 | ldata->column--; | |
a88a69c9 JP |
463 | break; |
464 | default: | |
a59c0d6f JP |
465 | if (!iscntrl(c)) { |
466 | if (O_OLCUC(tty)) | |
467 | c = toupper(c); | |
468 | if (!is_continuation(c, tty)) | |
53c5ee2c | 469 | ldata->column++; |
a59c0d6f | 470 | } |
a88a69c9 | 471 | break; |
1da177e4 | 472 | } |
a88a69c9 | 473 | |
f34d7a5b | 474 | tty_put_char(tty, c); |
a88a69c9 JP |
475 | return 1; |
476 | } | |
477 | ||
478 | /** | |
479 | * process_output - output post processor | |
480 | * @c: character (or partial unicode symbol) | |
481 | * @tty: terminal device | |
482 | * | |
ee5aa7b8 JP |
483 | * Output one character with OPOST processing. |
484 | * Returns -1 when the output device is full and the character | |
485 | * must be retried. | |
a88a69c9 JP |
486 | * |
487 | * Locking: output_lock to protect column state and space left | |
488 | * (also, this is called from n_tty_write under the | |
489 | * tty layer write lock) | |
490 | */ | |
491 | ||
492 | static int process_output(unsigned char c, struct tty_struct *tty) | |
493 | { | |
bddc7152 | 494 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
495 | int space, retval; |
496 | ||
bddc7152 | 497 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
498 | |
499 | space = tty_write_room(tty); | |
500 | retval = do_output_char(c, tty, space); | |
501 | ||
bddc7152 | 502 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
503 | if (retval < 0) |
504 | return -1; | |
505 | else | |
506 | return 0; | |
1da177e4 LT |
507 | } |
508 | ||
509 | /** | |
a88a69c9 | 510 | * process_output_block - block post processor |
1da177e4 | 511 | * @tty: terminal device |
ee5aa7b8 JP |
512 | * @buf: character buffer |
513 | * @nr: number of bytes to output | |
514 | * | |
515 | * Output a block of characters with OPOST processing. | |
516 | * Returns the number of characters output. | |
1da177e4 LT |
517 | * |
518 | * This path is used to speed up block console writes, among other | |
519 | * things when processing blocks of output data. It handles only | |
520 | * the simple cases normally found and helps to generate blocks of | |
521 | * symbols for the console driver and thus improve performance. | |
522 | * | |
a88a69c9 JP |
523 | * Locking: output_lock to protect column state and space left |
524 | * (also, this is called from n_tty_write under the | |
525 | * tty layer write lock) | |
1da177e4 | 526 | */ |
4edf1827 | 527 | |
a88a69c9 JP |
528 | static ssize_t process_output_block(struct tty_struct *tty, |
529 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 530 | { |
53c5ee2c | 531 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 532 | int space; |
bbd20759 | 533 | int i; |
1da177e4 LT |
534 | const unsigned char *cp; |
535 | ||
bddc7152 | 536 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 537 | |
f34d7a5b | 538 | space = tty_write_room(tty); |
300a6204 | 539 | if (!space) { |
bddc7152 | 540 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 541 | return 0; |
a88a69c9 | 542 | } |
1da177e4 LT |
543 | if (nr > space) |
544 | nr = space; | |
545 | ||
546 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
547 | unsigned char c = *cp; |
548 | ||
549 | switch (c) { | |
1da177e4 LT |
550 | case '\n': |
551 | if (O_ONLRET(tty)) | |
53c5ee2c | 552 | ldata->column = 0; |
1da177e4 LT |
553 | if (O_ONLCR(tty)) |
554 | goto break_out; | |
ba2e68ac | 555 | ldata->canon_column = ldata->column; |
1da177e4 LT |
556 | break; |
557 | case '\r': | |
53c5ee2c | 558 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
559 | goto break_out; |
560 | if (O_OCRNL(tty)) | |
561 | goto break_out; | |
ba2e68ac | 562 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
563 | break; |
564 | case '\t': | |
565 | goto break_out; | |
566 | case '\b': | |
53c5ee2c JS |
567 | if (ldata->column > 0) |
568 | ldata->column--; | |
1da177e4 LT |
569 | break; |
570 | default: | |
a59c0d6f JP |
571 | if (!iscntrl(c)) { |
572 | if (O_OLCUC(tty)) | |
573 | goto break_out; | |
574 | if (!is_continuation(c, tty)) | |
53c5ee2c | 575 | ldata->column++; |
a59c0d6f | 576 | } |
1da177e4 LT |
577 | break; |
578 | } | |
579 | } | |
580 | break_out: | |
f34d7a5b | 581 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 582 | |
bddc7152 | 583 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
584 | return i; |
585 | } | |
586 | ||
a88a69c9 JP |
587 | /** |
588 | * process_echoes - write pending echo characters | |
589 | * @tty: terminal device | |
590 | * | |
591 | * Write previously buffered echo (and other ldisc-generated) | |
592 | * characters to the tty. | |
593 | * | |
594 | * Characters generated by the ldisc (including echoes) need to | |
595 | * be buffered because the driver's write buffer can fill during | |
596 | * heavy program output. Echoing straight to the driver will | |
597 | * often fail under these conditions, causing lost characters and | |
598 | * resulting mismatches of ldisc state information. | |
599 | * | |
600 | * Since the ldisc state must represent the characters actually sent | |
601 | * to the driver at the time of the write, operations like certain | |
602 | * changes in column state are also saved in the buffer and executed | |
603 | * here. | |
604 | * | |
605 | * A circular fifo buffer is used so that the most recent characters | |
606 | * are prioritized. Also, when control characters are echoed with a | |
607 | * prefixed "^", the pair is treated atomically and thus not separated. | |
608 | * | |
019ebdf9 | 609 | * Locking: callers must hold output_lock |
a88a69c9 JP |
610 | */ |
611 | ||
bc5b1ec5 | 612 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 613 | { |
53c5ee2c | 614 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 615 | int space, old_space; |
addaebcc | 616 | size_t tail; |
a88a69c9 | 617 | unsigned char c; |
a88a69c9 | 618 | |
bc5b1ec5 | 619 | old_space = space = tty_write_room(tty); |
a88a69c9 | 620 | |
addaebcc | 621 | tail = ldata->echo_tail; |
29c7c5ca | 622 | while (ldata->echo_commit != tail) { |
addaebcc | 623 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
624 | if (c == ECHO_OP_START) { |
625 | unsigned char op; | |
a88a69c9 JP |
626 | int no_space_left = 0; |
627 | ||
628 | /* | |
629 | * If the buffer byte is the start of a multi-byte | |
630 | * operation, get the next byte, which is either the | |
631 | * op code or a control character value. | |
632 | */ | |
addaebcc | 633 | op = echo_buf(ldata, tail + 1); |
300a6204 | 634 | |
a88a69c9 JP |
635 | switch (op) { |
636 | unsigned int num_chars, num_bs; | |
637 | ||
638 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 639 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
640 | |
641 | /* | |
642 | * Determine how many columns to go back | |
643 | * in order to erase the tab. | |
644 | * This depends on the number of columns | |
645 | * used by other characters within the tab | |
646 | * area. If this (modulo 8) count is from | |
647 | * the start of input rather than from a | |
648 | * previous tab, we offset by canon column. | |
649 | * Otherwise, tab spacing is normal. | |
650 | */ | |
651 | if (!(num_chars & 0x80)) | |
ba2e68ac | 652 | num_chars += ldata->canon_column; |
a88a69c9 JP |
653 | num_bs = 8 - (num_chars & 7); |
654 | ||
655 | if (num_bs > space) { | |
656 | no_space_left = 1; | |
657 | break; | |
658 | } | |
659 | space -= num_bs; | |
660 | while (num_bs--) { | |
661 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
662 | if (ldata->column > 0) |
663 | ldata->column--; | |
a88a69c9 | 664 | } |
addaebcc | 665 | tail += 3; |
a88a69c9 JP |
666 | break; |
667 | ||
668 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 669 | ldata->canon_column = ldata->column; |
addaebcc | 670 | tail += 2; |
a88a69c9 JP |
671 | break; |
672 | ||
673 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
674 | if (ldata->column > 0) |
675 | ldata->column--; | |
addaebcc | 676 | tail += 2; |
a88a69c9 JP |
677 | break; |
678 | ||
679 | case ECHO_OP_START: | |
680 | /* This is an escaped echo op start code */ | |
681 | if (!space) { | |
682 | no_space_left = 1; | |
683 | break; | |
684 | } | |
685 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 686 | ldata->column++; |
a88a69c9 | 687 | space--; |
addaebcc | 688 | tail += 2; |
a88a69c9 JP |
689 | break; |
690 | ||
691 | default: | |
a88a69c9 | 692 | /* |
62b26358 JP |
693 | * If the op is not a special byte code, |
694 | * it is a ctrl char tagged to be echoed | |
695 | * as "^X" (where X is the letter | |
696 | * representing the control char). | |
697 | * Note that we must ensure there is | |
698 | * enough space for the whole ctrl pair. | |
699 | * | |
a88a69c9 | 700 | */ |
62b26358 JP |
701 | if (space < 2) { |
702 | no_space_left = 1; | |
703 | break; | |
704 | } | |
705 | tty_put_char(tty, '^'); | |
706 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 707 | ldata->column += 2; |
62b26358 | 708 | space -= 2; |
addaebcc | 709 | tail += 2; |
a88a69c9 JP |
710 | } |
711 | ||
712 | if (no_space_left) | |
713 | break; | |
714 | } else { | |
582f5590 | 715 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
716 | int retval = do_output_char(c, tty, space); |
717 | if (retval < 0) | |
718 | break; | |
719 | space -= retval; | |
720 | } else { | |
721 | if (!space) | |
722 | break; | |
723 | tty_put_char(tty, c); | |
724 | space -= 1; | |
725 | } | |
addaebcc | 726 | tail += 1; |
a88a69c9 | 727 | } |
a88a69c9 JP |
728 | } |
729 | ||
cbfd0340 PH |
730 | /* If the echo buffer is nearly full (so that the possibility exists |
731 | * of echo overrun before the next commit), then discard enough | |
732 | * data at the tail to prevent a subsequent overrun */ | |
733 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 734 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 735 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
736 | tail += 3; |
737 | else | |
738 | tail += 2; | |
739 | } else | |
740 | tail++; | |
741 | } | |
742 | ||
addaebcc | 743 | ldata->echo_tail = tail; |
bc5b1ec5 | 744 | return old_space - space; |
019ebdf9 PH |
745 | } |
746 | ||
747 | static void commit_echoes(struct tty_struct *tty) | |
748 | { | |
749 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 750 | size_t nr, old, echoed; |
cbfd0340 PH |
751 | size_t head; |
752 | ||
753 | head = ldata->echo_head; | |
1075a6e2 | 754 | ldata->echo_mark = head; |
cbfd0340 PH |
755 | old = ldata->echo_commit - ldata->echo_tail; |
756 | ||
757 | /* Process committed echoes if the accumulated # of bytes | |
758 | * is over the threshold (and try again each time another | |
759 | * block is accumulated) */ | |
760 | nr = head - ldata->echo_tail; | |
761 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
762 | return; | |
a88a69c9 | 763 | |
019ebdf9 | 764 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 765 | ldata->echo_commit = head; |
bc5b1ec5 | 766 | echoed = __process_echoes(tty); |
bddc7152 | 767 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 768 | |
bc5b1ec5 | 769 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
770 | tty->ops->flush_chars(tty); |
771 | } | |
772 | ||
019ebdf9 | 773 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
774 | { |
775 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 776 | size_t echoed; |
17bd7907 | 777 | |
e2613be5 | 778 | if (ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
779 | return; |
780 | ||
781 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 782 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 783 | echoed = __process_echoes(tty); |
019ebdf9 PH |
784 | mutex_unlock(&ldata->output_lock); |
785 | ||
bc5b1ec5 | 786 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 787 | tty->ops->flush_chars(tty); |
17bd7907 PH |
788 | } |
789 | ||
1075a6e2 | 790 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
791 | static void flush_echoes(struct tty_struct *tty) |
792 | { | |
793 | struct n_tty_data *ldata = tty->disc_data; | |
794 | ||
39434abd PH |
795 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
796 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
797 | return; |
798 | ||
799 | mutex_lock(&ldata->output_lock); | |
800 | ldata->echo_commit = ldata->echo_head; | |
801 | __process_echoes(tty); | |
802 | mutex_unlock(&ldata->output_lock); | |
803 | } | |
804 | ||
a88a69c9 JP |
805 | /** |
806 | * add_echo_byte - add a byte to the echo buffer | |
807 | * @c: unicode byte to echo | |
57c94121 | 808 | * @ldata: n_tty data |
a88a69c9 JP |
809 | * |
810 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
811 | */ |
812 | ||
cbfd0340 | 813 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 814 | { |
addaebcc | 815 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
816 | } |
817 | ||
818 | /** | |
819 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 820 | * @ldata: n_tty data |
a88a69c9 JP |
821 | * |
822 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
823 | */ |
824 | ||
57c94121 | 825 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 826 | { |
57c94121 JS |
827 | add_echo_byte(ECHO_OP_START, ldata); |
828 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
829 | } |
830 | ||
831 | /** | |
832 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 833 | * @ldata: n_tty data |
a88a69c9 JP |
834 | * |
835 | * Add an operation to the echo buffer to set the canon column | |
836 | * to the current column. | |
a88a69c9 JP |
837 | */ |
838 | ||
57c94121 | 839 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 840 | { |
57c94121 JS |
841 | add_echo_byte(ECHO_OP_START, ldata); |
842 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
843 | } |
844 | ||
845 | /** | |
846 | * echo_erase_tab - add operation to erase a tab | |
847 | * @num_chars: number of character columns already used | |
848 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 849 | * @ldata: n_tty data |
a88a69c9 JP |
850 | * |
851 | * Add an operation to the echo buffer to erase a tab. | |
852 | * | |
853 | * Called by the eraser function, which knows how many character | |
854 | * columns have been used since either a previous tab or the start | |
855 | * of input. This information will be used later, along with | |
856 | * canon column (if applicable), to go back the correct number | |
857 | * of columns. | |
a88a69c9 JP |
858 | */ |
859 | ||
860 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 861 | struct n_tty_data *ldata) |
a88a69c9 | 862 | { |
57c94121 JS |
863 | add_echo_byte(ECHO_OP_START, ldata); |
864 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
865 | |
866 | /* We only need to know this modulo 8 (tab spacing) */ | |
867 | num_chars &= 7; | |
868 | ||
869 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
870 | if (after_tab) | |
871 | num_chars |= 0x80; | |
300a6204 | 872 | |
57c94121 | 873 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
874 | } |
875 | ||
876 | /** | |
877 | * echo_char_raw - echo a character raw | |
878 | * @c: unicode byte to echo | |
879 | * @tty: terminal device | |
880 | * | |
881 | * Echo user input back onto the screen. This must be called only when | |
882 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
883 | * | |
884 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
885 | */ |
886 | ||
57c94121 | 887 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 888 | { |
a88a69c9 | 889 | if (c == ECHO_OP_START) { |
57c94121 JS |
890 | add_echo_byte(ECHO_OP_START, ldata); |
891 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 892 | } else { |
57c94121 | 893 | add_echo_byte(c, ldata); |
a88a69c9 | 894 | } |
a88a69c9 | 895 | } |
1da177e4 | 896 | |
1da177e4 | 897 | /** |
a88a69c9 | 898 | * echo_char - echo a character |
1da177e4 LT |
899 | * @c: unicode byte to echo |
900 | * @tty: terminal device | |
901 | * | |
4edf1827 | 902 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 903 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 904 | * |
62b26358 JP |
905 | * This variant tags control characters to be echoed as "^X" |
906 | * (where X is the letter representing the control char). | |
1da177e4 LT |
907 | */ |
908 | ||
909 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
910 | { | |
bddc7152 JS |
911 | struct n_tty_data *ldata = tty->disc_data; |
912 | ||
a88a69c9 | 913 | if (c == ECHO_OP_START) { |
57c94121 JS |
914 | add_echo_byte(ECHO_OP_START, ldata); |
915 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 916 | } else { |
62b26358 | 917 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
918 | add_echo_byte(ECHO_OP_START, ldata); |
919 | add_echo_byte(c, ldata); | |
a88a69c9 | 920 | } |
1da177e4 LT |
921 | } |
922 | ||
17b82060 | 923 | /** |
a88a69c9 | 924 | * finish_erasing - complete erase |
57c94121 | 925 | * @ldata: n_tty data |
17b82060 | 926 | */ |
a88a69c9 | 927 | |
57c94121 | 928 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 929 | { |
53c5ee2c | 930 | if (ldata->erasing) { |
57c94121 | 931 | echo_char_raw('/', ldata); |
53c5ee2c | 932 | ldata->erasing = 0; |
1da177e4 LT |
933 | } |
934 | } | |
935 | ||
936 | /** | |
937 | * eraser - handle erase function | |
938 | * @c: character input | |
939 | * @tty: terminal device | |
940 | * | |
3a4fa0a2 | 941 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
942 | * present in the stream from the driver layer. Handles the complexities |
943 | * of UTF-8 multibyte symbols. | |
17b82060 | 944 | * |
6d76bd26 PH |
945 | * n_tty_receive_buf()/producer path: |
946 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 947 | */ |
4edf1827 | 948 | |
1da177e4 LT |
949 | static void eraser(unsigned char c, struct tty_struct *tty) |
950 | { | |
53c5ee2c | 951 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 952 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
953 | size_t head; |
954 | size_t cnt; | |
955 | int seen_alnums; | |
1da177e4 | 956 | |
ba2e68ac | 957 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 958 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
959 | return; |
960 | } | |
961 | if (c == ERASE_CHAR(tty)) | |
962 | kill_type = ERASE; | |
963 | else if (c == WERASE_CHAR(tty)) | |
964 | kill_type = WERASE; | |
965 | else { | |
966 | if (!L_ECHO(tty)) { | |
ba2e68ac | 967 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
968 | return; |
969 | } | |
970 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 971 | ldata->read_head = ldata->canon_head; |
57c94121 | 972 | finish_erasing(ldata); |
1da177e4 LT |
973 | echo_char(KILL_CHAR(tty), tty); |
974 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
975 | if (L_ECHOK(tty)) | |
57c94121 | 976 | echo_char_raw('\n', ldata); |
1da177e4 LT |
977 | return; |
978 | } | |
979 | kill_type = KILL; | |
980 | } | |
981 | ||
982 | seen_alnums = 0; | |
63891322 | 983 | while (MASK(ldata->read_head) != MASK(ldata->canon_head)) { |
ba2e68ac | 984 | head = ldata->read_head; |
1da177e4 LT |
985 | |
986 | /* erase a single possibly multibyte character */ | |
987 | do { | |
bc5a5e3f PH |
988 | head--; |
989 | c = read_buf(ldata, head); | |
63891322 TH |
990 | } while (is_continuation(c, tty) && |
991 | MASK(head) != MASK(ldata->canon_head)); | |
1da177e4 LT |
992 | |
993 | /* do not partially erase */ | |
994 | if (is_continuation(c, tty)) | |
995 | break; | |
996 | ||
997 | if (kill_type == WERASE) { | |
998 | /* Equivalent to BSD's ALTWERASE. */ | |
999 | if (isalnum(c) || c == '_') | |
1000 | seen_alnums++; | |
1001 | else if (seen_alnums) | |
1002 | break; | |
1003 | } | |
bc5a5e3f | 1004 | cnt = ldata->read_head - head; |
ba2e68ac | 1005 | ldata->read_head = head; |
1da177e4 LT |
1006 | if (L_ECHO(tty)) { |
1007 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1008 | if (!ldata->erasing) { |
57c94121 | 1009 | echo_char_raw('\\', ldata); |
53c5ee2c | 1010 | ldata->erasing = 1; |
1da177e4 LT |
1011 | } |
1012 | /* if cnt > 1, output a multi-byte character */ | |
1013 | echo_char(c, tty); | |
1014 | while (--cnt > 0) { | |
bc5a5e3f PH |
1015 | head++; |
1016 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1017 | echo_move_back_col(ldata); |
1da177e4 LT |
1018 | } |
1019 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1020 | echo_char(ERASE_CHAR(tty), tty); | |
1021 | } else if (c == '\t') { | |
a88a69c9 JP |
1022 | unsigned int num_chars = 0; |
1023 | int after_tab = 0; | |
bc5a5e3f | 1024 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1025 | |
1026 | /* | |
1027 | * Count the columns used for characters | |
1028 | * since the start of input or after a | |
1029 | * previous tab. | |
1030 | * This info is used to go back the correct | |
1031 | * number of columns. | |
1032 | */ | |
63891322 | 1033 | while (MASK(tail) != MASK(ldata->canon_head)) { |
bc5a5e3f PH |
1034 | tail--; |
1035 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1036 | if (c == '\t') { |
1037 | after_tab = 1; | |
1038 | break; | |
300a6204 | 1039 | } else if (iscntrl(c)) { |
1da177e4 | 1040 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1041 | num_chars += 2; |
1042 | } else if (!is_continuation(c, tty)) { | |
1043 | num_chars++; | |
1044 | } | |
1da177e4 | 1045 | } |
57c94121 | 1046 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1047 | } else { |
1048 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1049 | echo_char_raw('\b', ldata); |
1050 | echo_char_raw(' ', ldata); | |
1051 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1052 | } |
1053 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1054 | echo_char_raw('\b', ldata); |
1055 | echo_char_raw(' ', ldata); | |
1056 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1057 | } |
1058 | } | |
1059 | } | |
1060 | if (kill_type == ERASE) | |
1061 | break; | |
1062 | } | |
ba2e68ac | 1063 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1064 | finish_erasing(ldata); |
1da177e4 LT |
1065 | } |
1066 | ||
1067 | /** | |
1068 | * isig - handle the ISIG optio | |
1069 | * @sig: signal | |
1070 | * @tty: terminal | |
1da177e4 | 1071 | * |
8c985d18 PH |
1072 | * Called when a signal is being sent due to terminal input. |
1073 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1074 | * |
d2b6f447 PH |
1075 | * Performs input and output flush if !NOFLSH. In this context, the echo |
1076 | * buffer is 'output'. The signal is processed first to alert any current | |
1077 | * readers or writers to discontinue and exit their i/o loops. | |
1078 | * | |
8c985d18 | 1079 | * Locking: ctrl_lock |
1da177e4 | 1080 | */ |
4edf1827 | 1081 | |
3b19e032 | 1082 | static void __isig(int sig, struct tty_struct *tty) |
1da177e4 | 1083 | { |
8c985d18 PH |
1084 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1085 | if (tty_pgrp) { | |
1086 | kill_pgrp(tty_pgrp, sig, 1); | |
1087 | put_pid(tty_pgrp); | |
1da177e4 | 1088 | } |
3b19e032 | 1089 | } |
d2b6f447 | 1090 | |
3b19e032 PH |
1091 | static void isig(int sig, struct tty_struct *tty) |
1092 | { | |
1093 | struct n_tty_data *ldata = tty->disc_data; | |
1094 | ||
1095 | if (L_NOFLSH(tty)) { | |
1096 | /* signal only */ | |
1097 | __isig(sig, tty); | |
1098 | ||
1099 | } else { /* signal and flush */ | |
d2b6f447 PH |
1100 | up_read(&tty->termios_rwsem); |
1101 | down_write(&tty->termios_rwsem); | |
1102 | ||
3b19e032 PH |
1103 | __isig(sig, tty); |
1104 | ||
d2b6f447 PH |
1105 | /* clear echo buffer */ |
1106 | mutex_lock(&ldata->output_lock); | |
1107 | ldata->echo_head = ldata->echo_tail = 0; | |
1108 | ldata->echo_mark = ldata->echo_commit = 0; | |
1109 | mutex_unlock(&ldata->output_lock); | |
1110 | ||
1111 | /* clear output buffer */ | |
1112 | tty_driver_flush_buffer(tty); | |
1113 | ||
1114 | /* clear input buffer */ | |
1115 | reset_buffer_flags(tty->disc_data); | |
1116 | ||
1117 | /* notify pty master of flush */ | |
1118 | if (tty->link) | |
1119 | n_tty_packet_mode_flush(tty); | |
1120 | ||
1121 | up_write(&tty->termios_rwsem); | |
1122 | down_read(&tty->termios_rwsem); | |
1123 | } | |
1da177e4 LT |
1124 | } |
1125 | ||
1126 | /** | |
1127 | * n_tty_receive_break - handle break | |
1128 | * @tty: terminal | |
1129 | * | |
1130 | * An RS232 break event has been hit in the incoming bitstream. This | |
1131 | * can cause a variety of events depending upon the termios settings. | |
1132 | * | |
6d76bd26 PH |
1133 | * n_tty_receive_buf()/producer path: |
1134 | * caller holds non-exclusive termios_rwsem | |
6d76bd26 PH |
1135 | * |
1136 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1137 | */ |
4edf1827 | 1138 | |
4b293492 | 1139 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1140 | { |
57c94121 JS |
1141 | struct n_tty_data *ldata = tty->disc_data; |
1142 | ||
1da177e4 LT |
1143 | if (I_IGNBRK(tty)) |
1144 | return; | |
1145 | if (I_BRKINT(tty)) { | |
8c985d18 | 1146 | isig(SIGINT, tty); |
1da177e4 LT |
1147 | return; |
1148 | } | |
1149 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1150 | put_tty_queue('\377', ldata); |
1151 | put_tty_queue('\0', ldata); | |
1da177e4 | 1152 | } |
57c94121 | 1153 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1154 | } |
1155 | ||
1156 | /** | |
1157 | * n_tty_receive_overrun - handle overrun reporting | |
1158 | * @tty: terminal | |
1159 | * | |
1160 | * Data arrived faster than we could process it. While the tty | |
1161 | * driver has flagged this the bits that were missed are gone | |
1162 | * forever. | |
1163 | * | |
1164 | * Called from the receive_buf path so single threaded. Does not | |
1165 | * need locking as num_overrun and overrun_time are function | |
1166 | * private. | |
1167 | */ | |
4edf1827 | 1168 | |
4b293492 | 1169 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1170 | { |
53c5ee2c | 1171 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1172 | |
53c5ee2c JS |
1173 | ldata->num_overrun++; |
1174 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1175 | time_after(ldata->overrun_time, jiffies)) { | |
339f36ba | 1176 | tty_warn(tty, "%d input overrun(s)\n", ldata->num_overrun); |
53c5ee2c JS |
1177 | ldata->overrun_time = jiffies; |
1178 | ldata->num_overrun = 0; | |
1da177e4 LT |
1179 | } |
1180 | } | |
1181 | ||
1182 | /** | |
1183 | * n_tty_receive_parity_error - error notifier | |
1184 | * @tty: terminal device | |
1185 | * @c: character | |
1186 | * | |
1187 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1188 | * the error case if necessary. |
1189 | * | |
1190 | * n_tty_receive_buf()/producer path: | |
1191 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 1192 | */ |
4b293492 | 1193 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1194 | { |
57c94121 JS |
1195 | struct n_tty_data *ldata = tty->disc_data; |
1196 | ||
66528f90 PH |
1197 | if (I_INPCK(tty)) { |
1198 | if (I_IGNPAR(tty)) | |
1199 | return; | |
1200 | if (I_PARMRK(tty)) { | |
1201 | put_tty_queue('\377', ldata); | |
1202 | put_tty_queue('\0', ldata); | |
1203 | put_tty_queue(c, ldata); | |
1204 | } else | |
1205 | put_tty_queue('\0', ldata); | |
1206 | } else | |
57c94121 | 1207 | put_tty_queue(c, ldata); |
1da177e4 LT |
1208 | } |
1209 | ||
b0ac50be PH |
1210 | static void |
1211 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1212 | { | |
d2b6f447 | 1213 | isig(signal, tty); |
b0ac50be PH |
1214 | if (I_IXON(tty)) |
1215 | start_tty(tty); | |
1216 | if (L_ECHO(tty)) { | |
1217 | echo_char(c, tty); | |
1218 | commit_echoes(tty); | |
e2613be5 PH |
1219 | } else |
1220 | process_echoes(tty); | |
b0ac50be PH |
1221 | return; |
1222 | } | |
1223 | ||
1da177e4 LT |
1224 | /** |
1225 | * n_tty_receive_char - perform processing | |
1226 | * @tty: terminal device | |
1227 | * @c: character | |
1228 | * | |
1229 | * Process an individual character of input received from the driver. | |
4edf1827 | 1230 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1231 | * driver above. |
6d76bd26 PH |
1232 | * |
1233 | * n_tty_receive_buf()/producer path: | |
1234 | * caller holds non-exclusive termios_rwsem | |
1235 | * publishes canon_head if canonical mode is active | |
e60d27c4 PH |
1236 | * |
1237 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1238 | */ |
1239 | ||
e60d27c4 | 1240 | static int |
4b1f79c2 | 1241 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1242 | { |
53c5ee2c | 1243 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1244 | |
1da177e4 LT |
1245 | if (I_IXON(tty)) { |
1246 | if (c == START_CHAR(tty)) { | |
1247 | start_tty(tty); | |
e2613be5 | 1248 | process_echoes(tty); |
e60d27c4 | 1249 | return 0; |
1da177e4 LT |
1250 | } |
1251 | if (c == STOP_CHAR(tty)) { | |
1252 | stop_tty(tty); | |
e60d27c4 | 1253 | return 0; |
1da177e4 LT |
1254 | } |
1255 | } | |
575537b3 | 1256 | |
1da177e4 | 1257 | if (L_ISIG(tty)) { |
b0ac50be PH |
1258 | if (c == INTR_CHAR(tty)) { |
1259 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1260 | return 0; |
b0ac50be PH |
1261 | } else if (c == QUIT_CHAR(tty)) { |
1262 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1263 | return 0; |
b0ac50be PH |
1264 | } else if (c == SUSP_CHAR(tty)) { |
1265 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1266 | return 0; |
1da177e4 LT |
1267 | } |
1268 | } | |
575537b3 | 1269 | |
855df3c0 PH |
1270 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1271 | start_tty(tty); | |
1272 | process_echoes(tty); | |
1273 | } | |
1274 | ||
575537b3 JP |
1275 | if (c == '\r') { |
1276 | if (I_IGNCR(tty)) | |
e60d27c4 | 1277 | return 0; |
575537b3 JP |
1278 | if (I_ICRNL(tty)) |
1279 | c = '\n'; | |
1280 | } else if (c == '\n' && I_INLCR(tty)) | |
1281 | c = '\r'; | |
1282 | ||
53c5ee2c | 1283 | if (ldata->icanon) { |
1da177e4 LT |
1284 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1285 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1286 | eraser(c, tty); | |
17bd7907 | 1287 | commit_echoes(tty); |
e60d27c4 | 1288 | return 0; |
1da177e4 LT |
1289 | } |
1290 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1291 | ldata->lnext = 1; |
1da177e4 | 1292 | if (L_ECHO(tty)) { |
57c94121 | 1293 | finish_erasing(ldata); |
1da177e4 | 1294 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1295 | echo_char_raw('^', ldata); |
1296 | echo_char_raw('\b', ldata); | |
17bd7907 | 1297 | commit_echoes(tty); |
1da177e4 LT |
1298 | } |
1299 | } | |
e60d27c4 | 1300 | return 1; |
1da177e4 | 1301 | } |
e60d27c4 | 1302 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1303 | size_t tail = ldata->canon_head; |
1da177e4 | 1304 | |
57c94121 | 1305 | finish_erasing(ldata); |
1da177e4 | 1306 | echo_char(c, tty); |
57c94121 | 1307 | echo_char_raw('\n', ldata); |
63891322 | 1308 | while (MASK(tail) != MASK(ldata->read_head)) { |
bc5a5e3f PH |
1309 | echo_char(read_buf(ldata, tail), tty); |
1310 | tail++; | |
1da177e4 | 1311 | } |
17bd7907 | 1312 | commit_echoes(tty); |
e60d27c4 | 1313 | return 0; |
1da177e4 LT |
1314 | } |
1315 | if (c == '\n') { | |
acc71bba | 1316 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1317 | echo_char_raw('\n', ldata); |
17bd7907 | 1318 | commit_echoes(tty); |
1da177e4 LT |
1319 | } |
1320 | goto handle_newline; | |
1321 | } | |
1322 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1323 | c = __DISABLED_CHAR; |
1324 | goto handle_newline; | |
1325 | } | |
1326 | if ((c == EOL_CHAR(tty)) || | |
1327 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1328 | /* | |
1329 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1330 | */ | |
1331 | if (L_ECHO(tty)) { | |
1da177e4 | 1332 | /* Record the column of first canon char. */ |
ba2e68ac | 1333 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1334 | echo_set_canon_col(ldata); |
1da177e4 | 1335 | echo_char(c, tty); |
17bd7907 | 1336 | commit_echoes(tty); |
1da177e4 LT |
1337 | } |
1338 | /* | |
1339 | * XXX does PARMRK doubling happen for | |
1340 | * EOL_CHAR and EOL2_CHAR? | |
1341 | */ | |
001ba923 | 1342 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
57c94121 | 1343 | put_tty_queue(c, ldata); |
1da177e4 | 1344 | |
4edf1827 | 1345 | handle_newline: |
bc5a5e3f | 1346 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1347 | put_tty_queue(c, ldata); |
70aca71f | 1348 | smp_store_release(&ldata->canon_head, ldata->read_head); |
1da177e4 | 1349 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
e81107d4 | 1350 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
e60d27c4 | 1351 | return 0; |
1da177e4 LT |
1352 | } |
1353 | } | |
4edf1827 | 1354 | |
acc71bba | 1355 | if (L_ECHO(tty)) { |
57c94121 | 1356 | finish_erasing(ldata); |
1da177e4 | 1357 | if (c == '\n') |
57c94121 | 1358 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1359 | else { |
1360 | /* Record the column of first canon char. */ | |
ba2e68ac | 1361 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1362 | echo_set_canon_col(ldata); |
1da177e4 LT |
1363 | echo_char(c, tty); |
1364 | } | |
17bd7907 | 1365 | commit_echoes(tty); |
1da177e4 LT |
1366 | } |
1367 | ||
001ba923 PH |
1368 | /* PARMRK doubling check */ |
1369 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
57c94121 | 1370 | put_tty_queue(c, ldata); |
1da177e4 | 1371 | |
57c94121 | 1372 | put_tty_queue(c, ldata); |
e60d27c4 | 1373 | return 0; |
4edf1827 | 1374 | } |
1da177e4 | 1375 | |
e60d27c4 PH |
1376 | static inline void |
1377 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1378 | { |
1379 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1380 | |
e60d27c4 PH |
1381 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1382 | start_tty(tty); | |
1383 | process_echoes(tty); | |
1384 | } | |
1385 | if (L_ECHO(tty)) { | |
1386 | finish_erasing(ldata); | |
1387 | /* Record the column of first canon char. */ | |
1388 | if (ldata->canon_head == ldata->read_head) | |
1389 | echo_set_canon_col(ldata); | |
1390 | echo_char(c, tty); | |
1391 | commit_echoes(tty); | |
4b1f79c2 | 1392 | } |
001ba923 PH |
1393 | /* PARMRK doubling check */ |
1394 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
e60d27c4 PH |
1395 | put_tty_queue(c, ldata); |
1396 | put_tty_queue(c, ldata); | |
1397 | } | |
4b1f79c2 | 1398 | |
eb3e4668 | 1399 | static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
e60d27c4 PH |
1400 | { |
1401 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1402 | } |
1403 | ||
7de971b0 PH |
1404 | static inline void |
1405 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1406 | { | |
1407 | struct n_tty_data *ldata = tty->disc_data; | |
1408 | ||
e60d27c4 PH |
1409 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1410 | start_tty(tty); | |
1411 | process_echoes(tty); | |
7de971b0 | 1412 | } |
e60d27c4 PH |
1413 | if (L_ECHO(tty)) { |
1414 | finish_erasing(ldata); | |
1415 | /* Record the column of first canon char. */ | |
1416 | if (ldata->canon_head == ldata->read_head) | |
1417 | echo_set_canon_col(ldata); | |
1418 | echo_char(c, tty); | |
1419 | commit_echoes(tty); | |
1420 | } | |
1421 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1422 | } |
1423 | ||
8dc4b25d | 1424 | static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) |
ad0cc7ba PH |
1425 | { |
1426 | if (I_ISTRIP(tty)) | |
1427 | c &= 0x7f; | |
1428 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1429 | c = tolower(c); | |
1430 | ||
1431 | if (I_IXON(tty)) { | |
1432 | if (c == STOP_CHAR(tty)) | |
1433 | stop_tty(tty); | |
1434 | else if (c == START_CHAR(tty) || | |
1435 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1436 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1437 | c != SUSP_CHAR(tty))) { | |
1438 | start_tty(tty); | |
1439 | process_echoes(tty); | |
1440 | } | |
1441 | } | |
1442 | } | |
1443 | ||
d2f8d7ab PH |
1444 | static void |
1445 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1446 | { | |
d2f8d7ab PH |
1447 | switch (flag) { |
1448 | case TTY_BREAK: | |
1449 | n_tty_receive_break(tty); | |
1450 | break; | |
1451 | case TTY_PARITY: | |
1452 | case TTY_FRAME: | |
1453 | n_tty_receive_parity_error(tty, c); | |
1454 | break; | |
1455 | case TTY_OVERRUN: | |
1456 | n_tty_receive_overrun(tty); | |
1457 | break; | |
1458 | default: | |
339f36ba | 1459 | tty_err(tty, "unknown flag %d\n", flag); |
d2f8d7ab PH |
1460 | break; |
1461 | } | |
1462 | } | |
1463 | ||
e60d27c4 PH |
1464 | static void |
1465 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1466 | { | |
1467 | struct n_tty_data *ldata = tty->disc_data; | |
1468 | ||
1469 | ldata->lnext = 0; | |
1470 | if (likely(flag == TTY_NORMAL)) { | |
1471 | if (I_ISTRIP(tty)) | |
1472 | c &= 0x7f; | |
1473 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1474 | c = tolower(c); | |
1475 | n_tty_receive_char(tty, c); | |
1476 | } else | |
1477 | n_tty_receive_char_flagged(tty, c, flag); | |
1478 | } | |
1479 | ||
4a23a4df PH |
1480 | static void |
1481 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1482 | char *fp, int count) | |
1483 | { | |
1484 | struct n_tty_data *ldata = tty->disc_data; | |
1485 | size_t n, head; | |
1486 | ||
1487 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1488 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1489 | memcpy(read_buf_addr(ldata, head), cp, n); |
1490 | ldata->read_head += n; | |
1491 | cp += n; | |
1492 | count -= n; | |
1493 | ||
1494 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1495 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1496 | memcpy(read_buf_addr(ldata, head), cp, n); |
1497 | ldata->read_head += n; | |
1498 | } | |
1499 | ||
554117bd PH |
1500 | static void |
1501 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1502 | char *fp, int count) | |
1503 | { | |
1504 | struct n_tty_data *ldata = tty->disc_data; | |
1505 | char flag = TTY_NORMAL; | |
1506 | ||
1507 | while (count--) { | |
1508 | if (fp) | |
1509 | flag = *fp++; | |
1510 | if (likely(flag == TTY_NORMAL)) | |
1511 | put_tty_queue(*cp++, ldata); | |
1512 | else | |
1513 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1514 | } | |
1515 | } | |
1516 | ||
ad0cc7ba PH |
1517 | static void |
1518 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1519 | char *fp, int count) | |
1520 | { | |
1521 | char flag = TTY_NORMAL; | |
1522 | ||
1523 | while (count--) { | |
1524 | if (fp) | |
1525 | flag = *fp++; | |
1526 | if (likely(flag == TTY_NORMAL)) | |
1527 | n_tty_receive_char_closing(tty, *cp++); | |
ad0cc7ba PH |
1528 | } |
1529 | } | |
1530 | ||
7d88d637 PH |
1531 | static void |
1532 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1533 | char *fp, int count) |
1534 | { | |
1535 | struct n_tty_data *ldata = tty->disc_data; | |
1536 | char flag = TTY_NORMAL; | |
1537 | ||
1538 | while (count--) { | |
1539 | if (fp) | |
1540 | flag = *fp++; | |
1541 | if (likely(flag == TTY_NORMAL)) { | |
1542 | unsigned char c = *cp++; | |
1543 | ||
1544 | if (I_ISTRIP(tty)) | |
1545 | c &= 0x7f; | |
1546 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1547 | c = tolower(c); | |
1548 | if (L_EXTPROC(tty)) { | |
1549 | put_tty_queue(c, ldata); | |
1550 | continue; | |
1551 | } | |
e60d27c4 PH |
1552 | if (!test_bit(c, ldata->char_map)) |
1553 | n_tty_receive_char_inline(tty, c); | |
1554 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1555 | if (fp) | |
1556 | flag = *fp++; | |
1557 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1558 | count--; | |
1559 | } | |
6baad008 PH |
1560 | } else |
1561 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1562 | } | |
1563 | } | |
1564 | ||
1565 | static void | |
1566 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1567 | char *fp, int count) | |
7d88d637 | 1568 | { |
e60d27c4 | 1569 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1570 | char flag = TTY_NORMAL; |
1571 | ||
1572 | while (count--) { | |
1573 | if (fp) | |
1574 | flag = *fp++; | |
e60d27c4 PH |
1575 | if (likely(flag == TTY_NORMAL)) { |
1576 | unsigned char c = *cp++; | |
1577 | ||
1578 | if (!test_bit(c, ldata->char_map)) | |
1579 | n_tty_receive_char_fast(tty, c); | |
1580 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1581 | if (fp) | |
1582 | flag = *fp++; | |
1583 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1584 | count--; | |
1585 | } | |
1586 | } else | |
7d88d637 PH |
1587 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1588 | } | |
1589 | } | |
1590 | ||
24a89d1c PH |
1591 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1592 | char *fp, int count) | |
1da177e4 | 1593 | { |
53c5ee2c | 1594 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1595 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1596 | |
4a23a4df PH |
1597 | if (ldata->real_raw) |
1598 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1599 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1600 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1601 | else if (tty->closing && !L_EXTPROC(tty)) |
1602 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1603 | else { |
e60d27c4 PH |
1604 | if (ldata->lnext) { |
1605 | char flag = TTY_NORMAL; | |
1606 | ||
1607 | if (fp) | |
1608 | flag = *fp++; | |
1609 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1610 | count--; | |
1611 | } | |
1612 | ||
7de971b0 | 1613 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1614 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1615 | else | |
1616 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1617 | |
1618 | flush_echoes(tty); | |
f34d7a5b AC |
1619 | if (tty->ops->flush_chars) |
1620 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1621 | } |
1622 | ||
70aca71f PH |
1623 | if (ldata->icanon && !L_EXTPROC(tty)) |
1624 | return; | |
1625 | ||
1626 | /* publish read_head to consumer */ | |
1627 | smp_store_release(&ldata->commit_head, ldata->read_head); | |
1628 | ||
33d71363 | 1629 | if (read_cnt(ldata)) { |
1da177e4 | 1630 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
e81107d4 | 1631 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 | 1632 | } |
1da177e4 LT |
1633 | } |
1634 | ||
fb5ef9e7 PH |
1635 | /** |
1636 | * n_tty_receive_buf_common - process input | |
1637 | * @tty: device to receive input | |
1638 | * @cp: input chars | |
1639 | * @fp: flags for each char (if NULL, all chars are TTY_NORMAL) | |
1640 | * @count: number of input chars in @cp | |
1641 | * | |
1642 | * Called by the terminal driver when a block of characters has | |
1643 | * been received. This function must be called from soft contexts | |
1644 | * not from interrupt context. The driver is responsible for making | |
1645 | * calls one at a time and in order (or using flush_to_ldisc) | |
1646 | * | |
1647 | * Returns the # of input chars from @cp which were processed. | |
1648 | * | |
1649 | * In canonical mode, the maximum line length is 4096 chars (including | |
1650 | * the line termination char); lines longer than 4096 chars are | |
1651 | * truncated. After 4095 chars, input data is still processed but | |
1652 | * not stored. Overflow processing ensures the tty can always | |
1653 | * receive more input until at least one line can be read. | |
1654 | * | |
1655 | * In non-canonical mode, the read buffer will only accept 4095 chars; | |
1656 | * this provides the necessary space for a newline char if the input | |
1657 | * mode is switched to canonical. | |
1658 | * | |
1659 | * Note it is possible for the read buffer to _contain_ 4096 chars | |
1660 | * in non-canonical mode: the read buffer could already contain the | |
1661 | * maximum canon line of 4096 chars when the mode is switched to | |
1662 | * non-canonical. | |
1663 | * | |
1664 | * n_tty_receive_buf()/producer path: | |
1665 | * claims non-exclusive termios_rwsem | |
1666 | * publishes commit_head or canon_head | |
1667 | */ | |
5c32d123 PH |
1668 | static int |
1669 | n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, | |
1670 | char *fp, int count, int flow) | |
24a89d1c PH |
1671 | { |
1672 | struct n_tty_data *ldata = tty->disc_data; | |
fb5ef9e7 | 1673 | int room, n, rcvd = 0, overflow; |
24a89d1c | 1674 | |
9356b535 PH |
1675 | down_read(&tty->termios_rwsem); |
1676 | ||
19e2ad6a | 1677 | while (1) { |
70aca71f | 1678 | /* |
06c49f9f PH |
1679 | * When PARMRK is set, each input char may take up to 3 chars |
1680 | * in the read buf; reduce the buffer space avail by 3x | |
70aca71f PH |
1681 | * |
1682 | * If we are doing input canonicalization, and there are no | |
1683 | * pending newlines, let characters through without limit, so | |
1684 | * that erase characters will be handled. Other excess | |
1685 | * characters will be beeped. | |
1686 | * | |
1687 | * paired with store in *_copy_from_read_buf() -- guarantees | |
1688 | * the consumer has loaded the data in read_buf up to the new | |
1689 | * read_tail (so this producer will not overwrite unread data) | |
1690 | */ | |
1691 | size_t tail = smp_load_acquire(&ldata->read_tail); | |
70aca71f | 1692 | |
fb5ef9e7 | 1693 | room = N_TTY_BUF_SIZE - (ldata->read_head - tail); |
70aca71f | 1694 | if (I_PARMRK(tty)) |
fb5ef9e7 PH |
1695 | room = (room + 2) / 3; |
1696 | room--; | |
1697 | if (room <= 0) { | |
1698 | overflow = ldata->icanon && ldata->canon_head == tail; | |
1699 | if (overflow && room < 0) | |
1700 | ldata->read_head--; | |
1701 | room = overflow; | |
1702 | ldata->no_room = flow && !room; | |
1703 | } else | |
1704 | overflow = 0; | |
70aca71f | 1705 | |
19e2ad6a | 1706 | n = min(count, room); |
fb5ef9e7 | 1707 | if (!n) |
19e2ad6a | 1708 | break; |
fb5ef9e7 PH |
1709 | |
1710 | /* ignore parity errors if handling overflow */ | |
1711 | if (!overflow || !fp || *fp != TTY_PARITY) | |
1712 | __receive_buf(tty, cp, fp, n); | |
1713 | ||
19e2ad6a PH |
1714 | cp += n; |
1715 | if (fp) | |
1716 | fp += n; | |
1717 | count -= n; | |
1718 | rcvd += n; | |
4a23a4df | 1719 | } |
24a89d1c | 1720 | |
19e2ad6a | 1721 | tty->receive_room = room; |
fb5ef9e7 PH |
1722 | |
1723 | /* Unthrottle if handling overflow on pty */ | |
1724 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { | |
1725 | if (overflow) { | |
1726 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1727 | tty_unthrottle_safe(tty); | |
1728 | __tty_set_flow_change(tty, 0); | |
1729 | } | |
1730 | } else | |
1731 | n_tty_check_throttle(tty); | |
1732 | ||
9356b535 PH |
1733 | up_read(&tty->termios_rwsem); |
1734 | ||
19e2ad6a | 1735 | return rcvd; |
24a89d1c PH |
1736 | } |
1737 | ||
5c32d123 PH |
1738 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1739 | char *fp, int count) | |
1740 | { | |
1741 | n_tty_receive_buf_common(tty, cp, fp, count, 0); | |
1742 | } | |
1743 | ||
1744 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1745 | char *fp, int count) | |
1746 | { | |
1747 | return n_tty_receive_buf_common(tty, cp, fp, count, 1); | |
1748 | } | |
1749 | ||
1da177e4 LT |
1750 | /** |
1751 | * n_tty_set_termios - termios data changed | |
1752 | * @tty: terminal | |
1753 | * @old: previous data | |
1754 | * | |
1755 | * Called by the tty layer when the user changes termios flags so | |
1756 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1757 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1758 | * guaranteed that this function will not be re-entered or in progress |
1759 | * when the ldisc is closed. | |
17b82060 | 1760 | * |
6a1c0680 | 1761 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1762 | */ |
4edf1827 AC |
1763 | |
1764 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1765 | { |
53c5ee2c | 1766 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1767 | |
966031f3 | 1768 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & (ICANON | EXTPROC)) { |
3fe780b3 | 1769 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1770 | ldata->line_start = ldata->read_tail; |
1771 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1772 | ldata->canon_head = ldata->read_tail; | |
1773 | ldata->push = 0; | |
1774 | } else { | |
1775 | set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), | |
1776 | ldata->read_flags); | |
1777 | ldata->canon_head = ldata->read_head; | |
1778 | ldata->push = 1; | |
1779 | } | |
70aca71f | 1780 | ldata->commit_head = ldata->read_head; |
53c5ee2c | 1781 | ldata->erasing = 0; |
6f9b028a | 1782 | ldata->lnext = 0; |
47afa7a5 AC |
1783 | } |
1784 | ||
53c5ee2c | 1785 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1786 | |
1da177e4 LT |
1787 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1788 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1789 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1790 | I_PARMRK(tty)) { | |
1bb9d562 | 1791 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1792 | |
1793 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1794 | set_bit('\r', ldata->char_map); |
1da177e4 | 1795 | if (I_INLCR(tty)) |
1bb9d562 | 1796 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1797 | |
1798 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1799 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1800 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1801 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1802 | set_bit('\n', ldata->char_map); | |
1803 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1804 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1805 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1806 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1807 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1808 | if (L_ECHO(tty)) |
1809 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1810 | ldata->char_map); |
1da177e4 LT |
1811 | } |
1812 | } | |
1813 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1814 | set_bit(START_CHAR(tty), ldata->char_map); |
1815 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1816 | } |
1817 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1818 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1819 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1820 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1821 | } |
1bb9d562 | 1822 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1823 | ldata->raw = 0; |
1824 | ldata->real_raw = 0; | |
1da177e4 | 1825 | } else { |
53c5ee2c | 1826 | ldata->raw = 1; |
1da177e4 LT |
1827 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1828 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1829 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1830 | ldata->real_raw = 1; |
1da177e4 | 1831 | else |
53c5ee2c | 1832 | ldata->real_raw = 0; |
1da177e4 | 1833 | } |
dab73b4e WY |
1834 | /* |
1835 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1836 | * been stopped by STOP_CHAR(tty) before it. | |
1837 | */ | |
e2613be5 | 1838 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { |
dab73b4e | 1839 | start_tty(tty); |
e2613be5 PH |
1840 | process_echoes(tty); |
1841 | } | |
dab73b4e | 1842 | |
f34d7a5b | 1843 | /* The termios change make the tty ready for I/O */ |
e81107d4 KT |
1844 | wake_up_interruptible(&tty->write_wait); |
1845 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1846 | } |
1847 | ||
1848 | /** | |
1849 | * n_tty_close - close the ldisc for this tty | |
1850 | * @tty: device | |
1851 | * | |
4edf1827 AC |
1852 | * Called from the terminal layer when this line discipline is |
1853 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1854 | * discipline change. The function will not be called while other |
1855 | * ldisc methods are in progress. | |
1856 | */ | |
4edf1827 | 1857 | |
1da177e4 LT |
1858 | static void n_tty_close(struct tty_struct *tty) |
1859 | { | |
70ece7a7 JS |
1860 | struct n_tty_data *ldata = tty->disc_data; |
1861 | ||
79901317 PH |
1862 | if (tty->link) |
1863 | n_tty_packet_mode_flush(tty); | |
1864 | ||
20bafb3d | 1865 | vfree(ldata); |
70ece7a7 | 1866 | tty->disc_data = NULL; |
1da177e4 LT |
1867 | } |
1868 | ||
1869 | /** | |
1870 | * n_tty_open - open an ldisc | |
1871 | * @tty: terminal to open | |
1872 | * | |
4edf1827 | 1873 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1874 | * terminal device. Can sleep. Called serialized so that no |
1875 | * other events will occur in parallel. No further open will occur | |
1876 | * until a close. | |
1877 | */ | |
1878 | ||
1879 | static int n_tty_open(struct tty_struct *tty) | |
1880 | { | |
70ece7a7 JS |
1881 | struct n_tty_data *ldata; |
1882 | ||
20bafb3d PH |
1883 | /* Currently a malloc failure here can panic */ |
1884 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1885 | if (!ldata) |
1886 | goto err; | |
1887 | ||
53c5ee2c | 1888 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1889 | mutex_init(&ldata->atomic_read_lock); |
1890 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1891 | |
70ece7a7 | 1892 | tty->disc_data = ldata; |
b66f4fa5 | 1893 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1894 | ldata->column = 0; |
20bafb3d | 1895 | ldata->canon_column = 0; |
20bafb3d PH |
1896 | ldata->num_overrun = 0; |
1897 | ldata->no_room = 0; | |
1898 | ldata->lnext = 0; | |
1da177e4 | 1899 | tty->closing = 0; |
b66f4fa5 PH |
1900 | /* indicate buffer work may resume */ |
1901 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1902 | n_tty_set_termios(tty, NULL); | |
1903 | tty_unthrottle(tty); | |
70ece7a7 | 1904 | |
1da177e4 | 1905 | return 0; |
70ece7a7 | 1906 | err: |
b91939f5 | 1907 | return -ENOMEM; |
1da177e4 LT |
1908 | } |
1909 | ||
eafbe67f | 1910 | static inline int input_available_p(struct tty_struct *tty, int poll) |
1da177e4 | 1911 | { |
53c5ee2c | 1912 | struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1913 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1914 | |
25e8d0ed PH |
1915 | if (ldata->icanon && !L_EXTPROC(tty)) |
1916 | return ldata->canon_head != ldata->read_tail; | |
1917 | else | |
70aca71f | 1918 | return ldata->commit_head - ldata->read_tail >= amt; |
1da177e4 LT |
1919 | } |
1920 | ||
1921 | /** | |
bbd20759 | 1922 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1923 | * @tty: terminal device |
1924 | * @b: user data | |
1925 | * @nr: size of data | |
1926 | * | |
11a96d18 | 1927 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1928 | * ICANON is off; it copies characters straight from the tty queue to |
1929 | * user space directly. It can be profitably called twice; once to | |
1930 | * drain the space from the tail pointer to the (physical) end of the | |
1931 | * buffer, and once to drain the space from the (physical) beginning of | |
1932 | * the buffer to head pointer. | |
1933 | * | |
bddc7152 | 1934 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1935 | * |
6d76bd26 PH |
1936 | * n_tty_read()/consumer path: |
1937 | * caller holds non-exclusive termios_rwsem | |
1938 | * read_tail published | |
1da177e4 | 1939 | */ |
4edf1827 | 1940 | |
33f0f88f | 1941 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1942 | unsigned char __user **b, |
1943 | size_t *nr) | |
1944 | ||
1945 | { | |
53c5ee2c | 1946 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1947 | int retval; |
1948 | size_t n; | |
3fa10cc8 | 1949 | bool is_eof; |
70aca71f | 1950 | size_t head = smp_load_acquire(&ldata->commit_head); |
bc5a5e3f | 1951 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1952 | |
1953 | retval = 0; | |
70aca71f | 1954 | n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail); |
1da177e4 | 1955 | n = min(*nr, n); |
1da177e4 | 1956 | if (n) { |
e661cf70 PH |
1957 | const unsigned char *from = read_buf_addr(ldata, tail); |
1958 | retval = copy_to_user(*b, from, n); | |
1da177e4 | 1959 | n -= retval; |
e661cf70 | 1960 | is_eof = n == 1 && *from == EOF_CHAR(tty); |
309426ae | 1961 | tty_audit_add_data(tty, from, n); |
70aca71f | 1962 | smp_store_release(&ldata->read_tail, ldata->read_tail + n); |
26df6d13 | 1963 | /* Turn single EOF into zero-length read */ |
70aca71f PH |
1964 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && |
1965 | (head == ldata->read_tail)) | |
3fa10cc8 | 1966 | n = 0; |
1da177e4 LT |
1967 | *b += n; |
1968 | *nr -= n; | |
1969 | } | |
1970 | return retval; | |
1971 | } | |
1972 | ||
88bb0de3 | 1973 | /** |
32f13521 | 1974 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1975 | * @tty: terminal device |
1976 | * @b: user data | |
1977 | * @nr: size of data | |
1978 | * | |
1979 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1980 | * it copies one line of input up to and including the line-delimiting |
1981 | * character into the user-space buffer. | |
88bb0de3 | 1982 | * |
4d0ed182 PH |
1983 | * NB: When termios is changed from non-canonical to canonical mode and |
1984 | * the read buffer contains data, n_tty_set_termios() simulates an EOF | |
1985 | * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. | |
1986 | * This causes data already processed as input to be immediately available | |
1987 | * as input although a newline has not been received. | |
1988 | * | |
88bb0de3 | 1989 | * Called under the atomic_read_lock mutex |
6d76bd26 PH |
1990 | * |
1991 | * n_tty_read()/consumer path: | |
1992 | * caller holds non-exclusive termios_rwsem | |
1993 | * read_tail published | |
88bb0de3 PH |
1994 | */ |
1995 | ||
32f13521 PH |
1996 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
1997 | unsigned char __user **b, | |
1998 | size_t *nr) | |
88bb0de3 PH |
1999 | { |
2000 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 2001 | size_t n, size, more, c; |
bc5a5e3f PH |
2002 | size_t eol; |
2003 | size_t tail; | |
2004 | int ret, found = 0; | |
88bb0de3 PH |
2005 | |
2006 | /* N.B. avoid overrun if nr == 0 */ | |
ac8f3bf8 | 2007 | if (!*nr) |
32f13521 | 2008 | return 0; |
88bb0de3 | 2009 | |
ac8f3bf8 PH |
2010 | n = min(*nr + 1, smp_load_acquire(&ldata->canon_head) - ldata->read_tail); |
2011 | ||
bc5a5e3f | 2012 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
2013 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
2014 | ||
bc5a5e3f | 2015 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2016 | __func__, *nr, tail, n, size); |
2017 | ||
2018 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2019 | more = n - (size - tail); | |
2020 | if (eol == N_TTY_BUF_SIZE && more) { | |
2021 | /* scan wrapped without finding set bit */ | |
2022 | eol = find_next_bit(ldata->read_flags, more, 0); | |
b985e9e3 PH |
2023 | found = eol != more; |
2024 | } else | |
2025 | found = eol != size; | |
32f13521 | 2026 | |
c77569d2 | 2027 | n = eol - tail; |
da555db6 MT |
2028 | if (n > N_TTY_BUF_SIZE) |
2029 | n += N_TTY_BUF_SIZE; | |
ac8f3bf8 | 2030 | c = n + found; |
32f13521 | 2031 | |
ac8f3bf8 PH |
2032 | if (!found || read_buf(ldata, eol) != __DISABLED_CHAR) { |
2033 | c = min(*nr, c); | |
2034 | n = c; | |
40d5e090 | 2035 | } |
32f13521 | 2036 | |
679e7c29 PH |
2037 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu tail:%zu more:%zu\n", |
2038 | __func__, eol, found, n, c, tail, more); | |
32f13521 | 2039 | |
679e7c29 | 2040 | ret = tty_copy_to_user(tty, *b, tail, n); |
32f13521 PH |
2041 | if (ret) |
2042 | return -EFAULT; | |
2043 | *b += n; | |
2044 | *nr -= n; | |
2045 | ||
a73d3d69 | 2046 | if (found) |
6d76bd26 | 2047 | clear_bit(eol, ldata->read_flags); |
70aca71f | 2048 | smp_store_release(&ldata->read_tail, ldata->read_tail + c); |
88bb0de3 | 2049 | |
40d5e090 | 2050 | if (found) { |
4d0ed182 PH |
2051 | if (!ldata->push) |
2052 | ldata->line_start = ldata->read_tail; | |
2053 | else | |
2054 | ldata->push = 0; | |
b50819f4 | 2055 | tty_audit_push(); |
40d5e090 | 2056 | } |
ac8f3bf8 | 2057 | return 0; |
88bb0de3 PH |
2058 | } |
2059 | ||
cc4191dc | 2060 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2061 | size_t, loff_t *); |
1da177e4 LT |
2062 | |
2063 | /** | |
2064 | * job_control - check job control | |
2065 | * @tty: tty | |
2066 | * @file: file handle | |
2067 | * | |
2068 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2069 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2070 | * error code if action should be taken. |
04f378b1 | 2071 | * |
01a5e440 PH |
2072 | * Locking: redirected write test is safe |
2073 | * current->signal->tty check is safe | |
2074 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2075 | */ |
4edf1827 | 2076 | |
1da177e4 LT |
2077 | static int job_control(struct tty_struct *tty, struct file *file) |
2078 | { | |
2079 | /* Job control check -- must be done at start and after | |
2080 | every sleep (POSIX.1 7.1.1.4). */ | |
2081 | /* NOTE: not yet done after every sleep pending a thorough | |
2082 | check of the logic of this change. -- jlc */ | |
2083 | /* don't stop on /dev/console */ | |
2812d9e9 | 2084 | if (file->f_op->write == redirected_tty_write) |
01a5e440 PH |
2085 | return 0; |
2086 | ||
2812d9e9 | 2087 | return __tty_check_change(tty, SIGTTIN); |
1da177e4 | 2088 | } |
4edf1827 | 2089 | |
1da177e4 LT |
2090 | |
2091 | /** | |
11a96d18 | 2092 | * n_tty_read - read function for tty |
1da177e4 LT |
2093 | * @tty: tty device |
2094 | * @file: file object | |
2095 | * @buf: userspace buffer pointer | |
2096 | * @nr: size of I/O | |
2097 | * | |
2098 | * Perform reads for the line discipline. We are guaranteed that the | |
2099 | * line discipline will not be closed under us but we may get multiple | |
2100 | * parallel readers and must handle this ourselves. We may also get | |
2101 | * a hangup. Always called in user context, may sleep. | |
2102 | * | |
2103 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2104 | * |
2105 | * n_tty_read()/consumer path: | |
2106 | * claims non-exclusive termios_rwsem | |
2107 | * publishes read_tail | |
1da177e4 | 2108 | */ |
4edf1827 | 2109 | |
11a96d18 | 2110 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2111 | unsigned char __user *buf, size_t nr) |
2112 | { | |
53c5ee2c | 2113 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 2114 | unsigned char __user *b = buf; |
97d9e28d | 2115 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
0f40fbbc | 2116 | int c; |
1da177e4 LT |
2117 | int minimum, time; |
2118 | ssize_t retval = 0; | |
1da177e4 | 2119 | long timeout; |
04f378b1 | 2120 | int packet; |
2c5dc464 | 2121 | size_t tail; |
1da177e4 | 2122 | |
1da177e4 | 2123 | c = job_control(tty, file); |
4edf1827 | 2124 | if (c < 0) |
1da177e4 | 2125 | return c; |
4edf1827 | 2126 | |
aefceaf4 PH |
2127 | /* |
2128 | * Internal serialization of reads. | |
2129 | */ | |
2130 | if (file->f_flags & O_NONBLOCK) { | |
2131 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2132 | return -EAGAIN; | |
2133 | } else { | |
2134 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2135 | return -ERESTARTSYS; | |
2136 | } | |
2137 | ||
9356b535 PH |
2138 | down_read(&tty->termios_rwsem); |
2139 | ||
1da177e4 LT |
2140 | minimum = time = 0; |
2141 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2142 | if (!ldata->icanon) { |
1da177e4 LT |
2143 | minimum = MIN_CHAR(tty); |
2144 | if (minimum) { | |
a6e54319 | 2145 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2146 | } else { |
a6e54319 | 2147 | timeout = (HZ / 10) * TIME_CHAR(tty); |
33d71363 | 2148 | minimum = 1; |
1da177e4 LT |
2149 | } |
2150 | } | |
2151 | ||
04f378b1 | 2152 | packet = tty->packet; |
2c5dc464 | 2153 | tail = ldata->read_tail; |
1da177e4 LT |
2154 | |
2155 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2156 | while (nr) { |
2157 | /* First test for status change. */ | |
04f378b1 | 2158 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2159 | unsigned char cs; |
2160 | if (b != buf) | |
2161 | break; | |
6054c16e | 2162 | spin_lock_irq(&tty->link->ctrl_lock); |
1da177e4 LT |
2163 | cs = tty->link->ctrl_status; |
2164 | tty->link->ctrl_status = 0; | |
6054c16e | 2165 | spin_unlock_irq(&tty->link->ctrl_lock); |
eab25a5c | 2166 | if (put_user(cs, b)) { |
1da177e4 | 2167 | retval = -EFAULT; |
1da177e4 LT |
2168 | break; |
2169 | } | |
eab25a5c | 2170 | b++; |
1da177e4 LT |
2171 | nr--; |
2172 | break; | |
2173 | } | |
4edf1827 | 2174 | |
1da177e4 | 2175 | if (!input_available_p(tty, 0)) { |
52bce7f8 | 2176 | up_read(&tty->termios_rwsem); |
0f40fbbc BB |
2177 | tty_buffer_flush_work(tty->port); |
2178 | down_read(&tty->termios_rwsem); | |
2179 | if (!input_available_p(tty, 0)) { | |
2180 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
2181 | retval = -EIO; | |
2182 | break; | |
2183 | } | |
2184 | if (tty_hung_up_p(file)) | |
2185 | break; | |
c720645a TH |
2186 | /* |
2187 | * Abort readers for ttys which never actually | |
2188 | * get hung up. See __tty_hangup(). | |
2189 | */ | |
2190 | if (test_bit(TTY_HUPPING, &tty->flags)) | |
2191 | break; | |
0f40fbbc BB |
2192 | if (!timeout) |
2193 | break; | |
2194 | if (file->f_flags & O_NONBLOCK) { | |
2195 | retval = -EAGAIN; | |
2196 | break; | |
2197 | } | |
2198 | if (signal_pending(current)) { | |
2199 | retval = -ERESTARTSYS; | |
2200 | break; | |
2201 | } | |
2202 | up_read(&tty->termios_rwsem); | |
9356b535 | 2203 | |
0f40fbbc BB |
2204 | timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, |
2205 | timeout); | |
9356b535 | 2206 | |
0f40fbbc BB |
2207 | down_read(&tty->termios_rwsem); |
2208 | continue; | |
2209 | } | |
1da177e4 LT |
2210 | } |
2211 | ||
53c5ee2c | 2212 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2213 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
ac8f3bf8 | 2214 | if (retval) |
1da177e4 LT |
2215 | break; |
2216 | } else { | |
2217 | int uncopied; | |
95ea90db PH |
2218 | |
2219 | /* Deal with packet mode. */ | |
2220 | if (packet && b == buf) { | |
eab25a5c | 2221 | if (put_user(TIOCPKT_DATA, b)) { |
95ea90db | 2222 | retval = -EFAULT; |
95ea90db PH |
2223 | break; |
2224 | } | |
eab25a5c | 2225 | b++; |
95ea90db PH |
2226 | nr--; |
2227 | } | |
2228 | ||
1da177e4 LT |
2229 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2230 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2231 | if (uncopied) { | |
2232 | retval = -EFAULT; | |
2233 | break; | |
2234 | } | |
2235 | } | |
2236 | ||
6367ca72 | 2237 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2238 | |
2239 | if (b - buf >= minimum) | |
2240 | break; | |
2241 | if (time) | |
2242 | timeout = time; | |
2243 | } | |
2c5dc464 PH |
2244 | if (tail != ldata->read_tail) |
2245 | n_tty_kick_worker(tty); | |
42458f41 PH |
2246 | up_read(&tty->termios_rwsem); |
2247 | ||
1da177e4 | 2248 | remove_wait_queue(&tty->read_wait, &wait); |
aebf0453 PH |
2249 | mutex_unlock(&ldata->atomic_read_lock); |
2250 | ||
40d5e090 PH |
2251 | if (b - buf) |
2252 | retval = b - buf; | |
1da177e4 LT |
2253 | |
2254 | return retval; | |
2255 | } | |
2256 | ||
2257 | /** | |
11a96d18 | 2258 | * n_tty_write - write function for tty |
1da177e4 LT |
2259 | * @tty: tty device |
2260 | * @file: file object | |
2261 | * @buf: userspace buffer pointer | |
2262 | * @nr: size of I/O | |
2263 | * | |
a88a69c9 | 2264 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2265 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2266 | * and other such events. Since the receive code will echo characters, |
2267 | * thus calling driver write methods, the output_lock is used in | |
2268 | * the output processing functions called here as well as in the | |
2269 | * echo processing function to protect the column state and space | |
2270 | * left in the buffer. | |
1da177e4 LT |
2271 | * |
2272 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2273 | * |
2274 | * Locking: output_lock to protect column state and space left | |
2275 | * (note that the process_output*() functions take this | |
2276 | * lock themselves) | |
1da177e4 | 2277 | */ |
4edf1827 | 2278 | |
11a96d18 | 2279 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2280 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2281 | { |
2282 | const unsigned char *b = buf; | |
97d9e28d | 2283 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2284 | int c; |
2285 | ssize_t retval = 0; | |
2286 | ||
2287 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2288 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2289 | retval = tty_check_change(tty); | |
2290 | if (retval) | |
2291 | return retval; | |
2292 | } | |
2293 | ||
9356b535 PH |
2294 | down_read(&tty->termios_rwsem); |
2295 | ||
a88a69c9 JP |
2296 | /* Write out any echoed characters that are still pending */ |
2297 | process_echoes(tty); | |
300a6204 | 2298 | |
1da177e4 LT |
2299 | add_wait_queue(&tty->write_wait, &wait); |
2300 | while (1) { | |
1da177e4 LT |
2301 | if (signal_pending(current)) { |
2302 | retval = -ERESTARTSYS; | |
2303 | break; | |
2304 | } | |
2305 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2306 | retval = -EIO; | |
2307 | break; | |
2308 | } | |
582f5590 | 2309 | if (O_OPOST(tty)) { |
1da177e4 | 2310 | while (nr > 0) { |
a88a69c9 | 2311 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2312 | if (num < 0) { |
2313 | if (num == -EAGAIN) | |
2314 | break; | |
2315 | retval = num; | |
2316 | goto break_out; | |
2317 | } | |
2318 | b += num; | |
2319 | nr -= num; | |
2320 | if (nr == 0) | |
2321 | break; | |
2322 | c = *b; | |
a88a69c9 | 2323 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2324 | break; |
2325 | b++; nr--; | |
2326 | } | |
f34d7a5b AC |
2327 | if (tty->ops->flush_chars) |
2328 | tty->ops->flush_chars(tty); | |
1da177e4 | 2329 | } else { |
4291086b PH |
2330 | struct n_tty_data *ldata = tty->disc_data; |
2331 | ||
d6afe27b | 2332 | while (nr > 0) { |
4291086b | 2333 | mutex_lock(&ldata->output_lock); |
f34d7a5b | 2334 | c = tty->ops->write(tty, b, nr); |
4291086b | 2335 | mutex_unlock(&ldata->output_lock); |
d6afe27b RZ |
2336 | if (c < 0) { |
2337 | retval = c; | |
2338 | goto break_out; | |
2339 | } | |
2340 | if (!c) | |
2341 | break; | |
2342 | b += c; | |
2343 | nr -= c; | |
1da177e4 | 2344 | } |
1da177e4 LT |
2345 | } |
2346 | if (!nr) | |
2347 | break; | |
2348 | if (file->f_flags & O_NONBLOCK) { | |
2349 | retval = -EAGAIN; | |
2350 | break; | |
2351 | } | |
9356b535 PH |
2352 | up_read(&tty->termios_rwsem); |
2353 | ||
97d9e28d | 2354 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
9356b535 PH |
2355 | |
2356 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2357 | } |
2358 | break_out: | |
1da177e4 | 2359 | remove_wait_queue(&tty->write_wait, &wait); |
87108bc9 | 2360 | if (nr && tty->fasync) |
ff8cb0fd | 2361 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
9356b535 | 2362 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2363 | return (b - buf) ? b - buf : retval; |
2364 | } | |
2365 | ||
2366 | /** | |
11a96d18 | 2367 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2368 | * @tty: terminal device |
2369 | * @file: file accessing it | |
2370 | * @wait: poll table | |
2371 | * | |
2372 | * Called when the line discipline is asked to poll() for data or | |
2373 | * for special events. This code is not serialized with respect to | |
2374 | * other events save open/close. | |
2375 | * | |
2376 | * This code must be sure never to sleep through a hangup. | |
2377 | * Called without the kernel lock held - fine | |
1da177e4 | 2378 | */ |
4edf1827 | 2379 | |
11a96d18 | 2380 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2381 | poll_table *wait) |
1da177e4 LT |
2382 | { |
2383 | unsigned int mask = 0; | |
2384 | ||
2385 | poll_wait(file, &tty->read_wait, wait); | |
2386 | poll_wait(file, &tty->write_wait, wait); | |
eafbe67f | 2387 | if (input_available_p(tty, 1)) |
1da177e4 | 2388 | mask |= POLLIN | POLLRDNORM; |
0f40fbbc BB |
2389 | else { |
2390 | tty_buffer_flush_work(tty->port); | |
2391 | if (input_available_p(tty, 1)) | |
2392 | mask |= POLLIN | POLLRDNORM; | |
2393 | } | |
1da177e4 LT |
2394 | if (tty->packet && tty->link->ctrl_status) |
2395 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
0f40fbbc BB |
2396 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) |
2397 | mask |= POLLHUP; | |
1da177e4 LT |
2398 | if (tty_hung_up_p(file)) |
2399 | mask |= POLLHUP; | |
f34d7a5b AC |
2400 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2401 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2402 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2403 | mask |= POLLOUT | POLLWRNORM; |
2404 | return mask; | |
2405 | } | |
2406 | ||
57c94121 | 2407 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2408 | { |
bc5a5e3f | 2409 | size_t nr, head, tail; |
47afa7a5 | 2410 | |
a73d3d69 | 2411 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2412 | return 0; |
ba2e68ac JS |
2413 | head = ldata->canon_head; |
2414 | tail = ldata->read_tail; | |
bc5a5e3f | 2415 | nr = head - tail; |
47afa7a5 | 2416 | /* Skip EOF-chars.. */ |
63891322 | 2417 | while (MASK(head) != MASK(tail)) { |
bc5a5e3f PH |
2418 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2419 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2420 | nr--; |
bc5a5e3f | 2421 | tail++; |
47afa7a5 AC |
2422 | } |
2423 | return nr; | |
2424 | } | |
2425 | ||
2426 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2427 | unsigned int cmd, unsigned long arg) | |
2428 | { | |
ba2e68ac | 2429 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2430 | int retval; |
2431 | ||
2432 | switch (cmd) { | |
2433 | case TIOCOUTQ: | |
2434 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2435 | case TIOCINQ: | |
6d76bd26 | 2436 | down_write(&tty->termios_rwsem); |
966031f3 | 2437 | if (L_ICANON(tty) && !L_EXTPROC(tty)) |
57c94121 | 2438 | retval = inq_canon(ldata); |
6d76bd26 PH |
2439 | else |
2440 | retval = read_cnt(ldata); | |
2441 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2442 | return put_user(retval, (unsigned int __user *) arg); |
2443 | default: | |
2444 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2445 | } | |
2446 | } | |
2447 | ||
27228732 | 2448 | static struct tty_ldisc_ops n_tty_ops = { |
e10cc1df PF |
2449 | .magic = TTY_LDISC_MAGIC, |
2450 | .name = "n_tty", | |
2451 | .open = n_tty_open, | |
2452 | .close = n_tty_close, | |
2453 | .flush_buffer = n_tty_flush_buffer, | |
11a96d18 AC |
2454 | .read = n_tty_read, |
2455 | .write = n_tty_write, | |
e10cc1df PF |
2456 | .ioctl = n_tty_ioctl, |
2457 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2458 | .poll = n_tty_poll, |
e10cc1df | 2459 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 | 2460 | .write_wakeup = n_tty_write_wakeup, |
24a89d1c | 2461 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2462 | }; |
572b9adb RG |
2463 | |
2464 | /** | |
2465 | * n_tty_inherit_ops - inherit N_TTY methods | |
2466 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2467 | * | |
27228732 | 2468 | * Enables a 'subclass' line discipline to 'inherit' N_TTY methods. |
572b9adb RG |
2469 | */ |
2470 | ||
2471 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2472 | { | |
27228732 | 2473 | *ops = n_tty_ops; |
572b9adb RG |
2474 | ops->owner = NULL; |
2475 | ops->refcount = ops->flags = 0; | |
2476 | } | |
2477 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); | |
27228732 PH |
2478 | |
2479 | void __init n_tty_init(void) | |
2480 | { | |
2481 | tty_register_ldisc(N_TTY, &n_tty_ops); | |
2482 | } |