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