Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * n_tty.c --- implements the N_TTY line discipline. | |
4edf1827 | 3 | * |
1da177e4 LT |
4 | * This code used to be in tty_io.c, but things are getting hairy |
5 | * enough that it made sense to split things off. (The N_TTY | |
6 | * processing has changed so much that it's hardly recognizable, | |
7 | * anyway...) | |
8 | * | |
9 | * Note that the open routine for N_TTY is guaranteed never to return | |
10 | * an error. This is because Linux will fall back to setting a line | |
4edf1827 | 11 | * to N_TTY if it can not switch to any other line discipline. |
1da177e4 LT |
12 | * |
13 | * Written by Theodore Ts'o, Copyright 1994. | |
4edf1827 | 14 | * |
1da177e4 LT |
15 | * This file also contains code originally written by Linus Torvalds, |
16 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. | |
4edf1827 | 17 | * |
1da177e4 LT |
18 | * This file may be redistributed under the terms of the GNU General Public |
19 | * License. | |
20 | * | |
21 | * Reduced memory usage for older ARM systems - Russell King. | |
22 | * | |
4edf1827 | 23 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
1da177e4 LT |
24 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
25 | * who actually finally proved there really was a race. | |
26 | * | |
27 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to | |
28 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. | |
11a96d18 | 29 | * Also fixed a bug in BLOCKING mode where n_tty_write returns |
1da177e4 LT |
30 | * EAGAIN |
31 | */ | |
32 | ||
33 | #include <linux/types.h> | |
34 | #include <linux/major.h> | |
35 | #include <linux/errno.h> | |
36 | #include <linux/signal.h> | |
37 | #include <linux/fcntl.h> | |
38 | #include <linux/sched.h> | |
39 | #include <linux/interrupt.h> | |
40 | #include <linux/tty.h> | |
41 | #include <linux/timer.h> | |
42 | #include <linux/ctype.h> | |
43 | #include <linux/mm.h> | |
44 | #include <linux/string.h> | |
45 | #include <linux/slab.h> | |
46 | #include <linux/poll.h> | |
47 | #include <linux/bitops.h> | |
522ed776 MT |
48 | #include <linux/audit.h> |
49 | #include <linux/file.h> | |
300a6204 | 50 | #include <linux/uaccess.h> |
572b9adb | 51 | #include <linux/module.h> |
593fb1ae | 52 | #include <linux/ratelimit.h> |
86e35aea | 53 | #include <linux/vmalloc.h> |
1da177e4 | 54 | |
1da177e4 LT |
55 | |
56 | /* number of characters left in xmit buffer before select has we have room */ | |
57 | #define WAKEUP_CHARS 256 | |
58 | ||
59 | /* | |
60 | * This defines the low- and high-watermarks for throttling and | |
61 | * unthrottling the TTY driver. These watermarks are used for | |
62 | * controlling the space in the read buffer. | |
63 | */ | |
64 | #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ | |
bbd20759 | 65 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
1da177e4 | 66 | |
a88a69c9 JP |
67 | /* |
68 | * Special byte codes used in the echo buffer to represent operations | |
69 | * or special handling of characters. Bytes in the echo buffer that | |
70 | * are not part of such special blocks are treated as normal character | |
71 | * codes. | |
72 | */ | |
73 | #define ECHO_OP_START 0xff | |
74 | #define ECHO_OP_MOVE_BACK_COL 0x80 | |
75 | #define ECHO_OP_SET_CANON_COL 0x81 | |
76 | #define ECHO_OP_ERASE_TAB 0x82 | |
77 | ||
cbfd0340 PH |
78 | #define ECHO_COMMIT_WATERMARK 256 |
79 | #define ECHO_BLOCK 256 | |
80 | #define ECHO_DISCARD_WATERMARK N_TTY_BUF_SIZE - (ECHO_BLOCK + 32) | |
81 | ||
82 | ||
32f13521 PH |
83 | #undef N_TTY_TRACE |
84 | #ifdef N_TTY_TRACE | |
85 | # define n_tty_trace(f, args...) trace_printk(f, ##args) | |
86 | #else | |
87 | # define n_tty_trace(f, args...) | |
88 | #endif | |
89 | ||
70ece7a7 | 90 | struct n_tty_data { |
fb7aa03d PH |
91 | /* producer-published */ |
92 | size_t read_head; | |
70aca71f | 93 | size_t commit_head; |
fb7aa03d | 94 | size_t canon_head; |
9dfd16dd PH |
95 | size_t echo_head; |
96 | size_t echo_commit; | |
1075a6e2 | 97 | size_t echo_mark; |
1bb9d562 | 98 | DECLARE_BITMAP(char_map, 256); |
fb7aa03d PH |
99 | |
100 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c JS |
101 | unsigned long overrun_time; |
102 | int num_overrun; | |
103 | ||
24a89d1c PH |
104 | /* non-atomic */ |
105 | bool no_room; | |
106 | ||
fb7aa03d | 107 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c | 108 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
4d0ed182 | 109 | unsigned char push:1; |
3fe780b3 | 110 | |
fb7aa03d | 111 | /* shared by producer and consumer */ |
20bafb3d | 112 | char read_buf[N_TTY_BUF_SIZE]; |
3fe780b3 | 113 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
20bafb3d | 114 | unsigned char echo_buf[N_TTY_BUF_SIZE]; |
ba2e68ac | 115 | |
fb7aa03d PH |
116 | /* consumer-published */ |
117 | size_t read_tail; | |
40d5e090 | 118 | size_t line_start; |
fb7aa03d | 119 | |
fb7aa03d PH |
120 | /* protected by output lock */ |
121 | unsigned int column; | |
ba2e68ac | 122 | unsigned int canon_column; |
9dfd16dd | 123 | size_t echo_tail; |
bddc7152 JS |
124 | |
125 | struct mutex atomic_read_lock; | |
126 | struct mutex output_lock; | |
70ece7a7 JS |
127 | }; |
128 | ||
ce74117a PH |
129 | static inline size_t read_cnt(struct n_tty_data *ldata) |
130 | { | |
a2f73be8 | 131 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
132 | } |
133 | ||
bc5a5e3f PH |
134 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
135 | { | |
136 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
137 | } | |
138 | ||
139 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
140 | { | |
141 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
142 | } | |
143 | ||
addaebcc PH |
144 | static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) |
145 | { | |
146 | return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
147 | } | |
148 | ||
149 | static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) | |
150 | { | |
151 | return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
152 | } | |
153 | ||
679e7c29 PH |
154 | static int tty_copy_to_user(struct tty_struct *tty, void __user *to, |
155 | size_t tail, size_t n) | |
72586c60 LA |
156 | { |
157 | struct n_tty_data *ldata = tty->disc_data; | |
679e7c29 PH |
158 | size_t size = N_TTY_BUF_SIZE - tail; |
159 | const void *from = read_buf_addr(ldata, tail); | |
160 | int uncopied; | |
161 | ||
162 | if (n > size) { | |
309426ae | 163 | tty_audit_add_data(tty, from, size); |
679e7c29 PH |
164 | uncopied = copy_to_user(to, from, size); |
165 | if (uncopied) | |
166 | return uncopied; | |
167 | to += size; | |
168 | n -= size; | |
169 | from = ldata->read_buf; | |
170 | } | |
72586c60 | 171 | |
309426ae | 172 | tty_audit_add_data(tty, from, n); |
72586c60 LA |
173 | return copy_to_user(to, from, n); |
174 | } | |
175 | ||
24a89d1c | 176 | /** |
2c5dc464 | 177 | * n_tty_kick_worker - start input worker (if required) |
24a89d1c PH |
178 | * @tty: terminal |
179 | * | |
2c5dc464 | 180 | * Re-schedules the flip buffer work if it may have stopped |
24a89d1c | 181 | * |
6d76bd26 PH |
182 | * Caller holds exclusive termios_rwsem |
183 | * or | |
184 | * n_tty_read()/consumer path: | |
185 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
186 | */ |
187 | ||
2c5dc464 | 188 | static void n_tty_kick_worker(struct tty_struct *tty) |
7879a9f9 | 189 | { |
24a89d1c PH |
190 | struct n_tty_data *ldata = tty->disc_data; |
191 | ||
2c5dc464 PH |
192 | /* Did the input worker stop? Restart it */ |
193 | if (unlikely(ldata->no_room)) { | |
24a89d1c PH |
194 | ldata->no_room = 0; |
195 | ||
ecbbfd44 | 196 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 197 | "scheduling with invalid itty\n"); |
21622939 PH |
198 | /* see if ldisc has been killed - if so, this means that |
199 | * even though the ldisc has been halted and ->buf.work | |
200 | * cancelled, ->buf.work is about to be rescheduled | |
201 | */ | |
202 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
203 | "scheduling buffer work for halted ldisc\n"); | |
e176058f | 204 | tty_buffer_restart_work(tty->port); |
ecbbfd44 | 205 | } |
55db4c64 LT |
206 | } |
207 | ||
9a4aec2d PH |
208 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
209 | { | |
210 | struct n_tty_data *ldata = tty->disc_data; | |
211 | ssize_t n = 0; | |
212 | ||
213 | if (!ldata->icanon) | |
70aca71f | 214 | n = ldata->commit_head - ldata->read_tail; |
9a4aec2d PH |
215 | else |
216 | n = ldata->canon_head - ldata->read_tail; | |
217 | return n; | |
218 | } | |
219 | ||
ee0bab83 PH |
220 | /** |
221 | * n_tty_write_wakeup - asynchronous I/O notifier | |
222 | * @tty: tty device | |
223 | * | |
224 | * Required for the ptys, serial driver etc. since processes | |
225 | * that attach themselves to the master and rely on ASYNC | |
226 | * IO must be woken up | |
227 | */ | |
228 | ||
229 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
230 | { | |
7bccc365 PH |
231 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
232 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
ee0bab83 PH |
233 | } |
234 | ||
4a23a4df | 235 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 236 | { |
a342846f PH |
237 | struct n_tty_data *ldata = tty->disc_data; |
238 | ||
6367ca72 PH |
239 | /* |
240 | * Check the remaining room for the input canonicalization | |
241 | * mode. We don't want to throttle the driver if we're in | |
242 | * canonical mode and don't have a newline yet! | |
243 | */ | |
a342846f PH |
244 | if (ldata->icanon && ldata->canon_head == ldata->read_tail) |
245 | return; | |
246 | ||
6367ca72 PH |
247 | while (1) { |
248 | int throttled; | |
249 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
5e28cca1 | 250 | if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE) |
6367ca72 PH |
251 | break; |
252 | throttled = tty_throttle_safe(tty); | |
253 | if (!throttled) | |
254 | break; | |
255 | } | |
256 | __tty_set_flow_change(tty, 0); | |
257 | } | |
258 | ||
4b293492 | 259 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 260 | { |
6d27a63c | 261 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { |
3afb1b39 PH |
262 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) |
263 | return; | |
2c5dc464 | 264 | n_tty_kick_worker(tty); |
6d27a63c | 265 | tty_wakeup(tty->link); |
3afb1b39 PH |
266 | return; |
267 | } | |
268 | ||
6367ca72 PH |
269 | /* If there is enough space in the read buffer now, let the |
270 | * low-level driver know. We use chars_in_buffer() to | |
271 | * check the buffer, as it now knows about canonical mode. | |
272 | * Otherwise, if the driver is throttled and the line is | |
273 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
274 | * we won't get any more characters. | |
275 | */ | |
276 | ||
277 | while (1) { | |
278 | int unthrottled; | |
279 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
280 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
281 | break; | |
2c5dc464 | 282 | n_tty_kick_worker(tty); |
6367ca72 PH |
283 | unthrottled = tty_unthrottle_safe(tty); |
284 | if (!unthrottled) | |
285 | break; | |
286 | } | |
287 | __tty_set_flow_change(tty, 0); | |
288 | } | |
289 | ||
17b82060 AC |
290 | /** |
291 | * put_tty_queue - add character to tty | |
292 | * @c: character | |
57c94121 | 293 | * @ldata: n_tty data |
17b82060 | 294 | * |
6d76bd26 PH |
295 | * Add a character to the tty read_buf queue. |
296 | * | |
297 | * n_tty_receive_buf()/producer path: | |
298 | * caller holds non-exclusive termios_rwsem | |
17b82060 AC |
299 | */ |
300 | ||
19e2ad6a | 301 | static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 302 | { |
8bfbe2de CR |
303 | *read_buf_addr(ldata, ldata->read_head) = c; |
304 | ldata->read_head++; | |
1da177e4 LT |
305 | } |
306 | ||
1da177e4 LT |
307 | /** |
308 | * reset_buffer_flags - reset buffer state | |
309 | * @tty: terminal to reset | |
310 | * | |
25518c68 PH |
311 | * Reset the read buffer counters and clear the flags. |
312 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 313 | * |
6d76bd26 PH |
314 | * Locking: caller holds exclusive termios_rwsem |
315 | * (or locking is not required) | |
1da177e4 | 316 | */ |
a88a69c9 | 317 | |
b66f4fa5 | 318 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 319 | { |
a73d3d69 | 320 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 321 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
70aca71f | 322 | ldata->commit_head = 0; |
1075a6e2 | 323 | ldata->echo_mark = 0; |
40d5e090 | 324 | ldata->line_start = 0; |
a88a69c9 | 325 | |
a73d3d69 | 326 | ldata->erasing = 0; |
3fe780b3 | 327 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 | 328 | ldata->push = 0; |
1da177e4 LT |
329 | } |
330 | ||
a30737ab PH |
331 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
332 | { | |
333 | unsigned long flags; | |
334 | ||
a30737ab | 335 | if (tty->link->packet) { |
54e8e5fc | 336 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
a30737ab | 337 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; |
54e8e5fc | 338 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
e81107d4 | 339 | wake_up_interruptible(&tty->link->read_wait); |
a30737ab | 340 | } |
a30737ab PH |
341 | } |
342 | ||
1da177e4 LT |
343 | /** |
344 | * n_tty_flush_buffer - clean input queue | |
345 | * @tty: terminal device | |
346 | * | |
25518c68 PH |
347 | * Flush the input buffer. Called when the tty layer wants the |
348 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
349 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 350 | * |
6d76bd26 PH |
351 | * Holds termios_rwsem to exclude producer/consumer while |
352 | * buffer indices are reset. | |
353 | * | |
354 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 355 | */ |
4edf1827 AC |
356 | |
357 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 358 | { |
6d76bd26 | 359 | down_write(&tty->termios_rwsem); |
b66f4fa5 | 360 | reset_buffer_flags(tty->disc_data); |
2c5dc464 | 361 | n_tty_kick_worker(tty); |
4edf1827 | 362 | |
a30737ab PH |
363 | if (tty->link) |
364 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 365 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
366 | } |
367 | ||
1da177e4 LT |
368 | /** |
369 | * is_utf8_continuation - utf8 multibyte check | |
370 | * @c: byte to check | |
371 | * | |
372 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
373 | * character. We use this to correctly compute the on screen size | |
374 | * of the character when printing | |
375 | */ | |
4edf1827 | 376 | |
1da177e4 LT |
377 | static inline int is_utf8_continuation(unsigned char c) |
378 | { | |
379 | return (c & 0xc0) == 0x80; | |
380 | } | |
381 | ||
382 | /** | |
383 | * is_continuation - multibyte check | |
384 | * @c: byte to check | |
385 | * | |
386 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
387 | * character and the terminal is in unicode mode. | |
388 | */ | |
4edf1827 | 389 | |
1da177e4 LT |
390 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
391 | { | |
392 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
393 | } | |
394 | ||
395 | /** | |
a88a69c9 | 396 | * do_output_char - output one character |
1da177e4 LT |
397 | * @c: character (or partial unicode symbol) |
398 | * @tty: terminal device | |
a88a69c9 | 399 | * @space: space available in tty driver write buffer |
1da177e4 | 400 | * |
a88a69c9 JP |
401 | * This is a helper function that handles one output character |
402 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
403 | * doing OPOST processing and putting the results in the |
404 | * tty driver's write buffer. | |
a88a69c9 JP |
405 | * |
406 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
407 | * and NLDLY. They simply aren't relevant in the world today. | |
408 | * If you ever need them, add them here. | |
1da177e4 | 409 | * |
a88a69c9 JP |
410 | * Returns the number of bytes of buffer space used or -1 if |
411 | * no space left. | |
412 | * | |
413 | * Locking: should be called under the output_lock to protect | |
414 | * the column state and space left in the buffer | |
1da177e4 | 415 | */ |
4edf1827 | 416 | |
a88a69c9 | 417 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 418 | { |
53c5ee2c | 419 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 420 | int spaces; |
1da177e4 | 421 | |
1da177e4 LT |
422 | if (!space) |
423 | return -1; | |
300a6204 | 424 | |
a88a69c9 JP |
425 | switch (c) { |
426 | case '\n': | |
427 | if (O_ONLRET(tty)) | |
53c5ee2c | 428 | ldata->column = 0; |
a88a69c9 JP |
429 | if (O_ONLCR(tty)) { |
430 | if (space < 2) | |
431 | return -1; | |
ba2e68ac | 432 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 433 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
434 | return 2; |
435 | } | |
ba2e68ac | 436 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
437 | break; |
438 | case '\r': | |
53c5ee2c | 439 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
440 | return 0; |
441 | if (O_OCRNL(tty)) { | |
442 | c = '\n'; | |
443 | if (O_ONLRET(tty)) | |
ba2e68ac | 444 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 445 | break; |
a88a69c9 | 446 | } |
ba2e68ac | 447 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
448 | break; |
449 | case '\t': | |
53c5ee2c | 450 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
451 | if (O_TABDLY(tty) == XTABS) { |
452 | if (space < spaces) | |
453 | return -1; | |
53c5ee2c | 454 | ldata->column += spaces; |
a88a69c9 JP |
455 | tty->ops->write(tty, " ", spaces); |
456 | return spaces; | |
1da177e4 | 457 | } |
53c5ee2c | 458 | ldata->column += spaces; |
a88a69c9 JP |
459 | break; |
460 | case '\b': | |
53c5ee2c JS |
461 | if (ldata->column > 0) |
462 | ldata->column--; | |
a88a69c9 JP |
463 | break; |
464 | default: | |
a59c0d6f JP |
465 | if (!iscntrl(c)) { |
466 | if (O_OLCUC(tty)) | |
467 | c = toupper(c); | |
468 | if (!is_continuation(c, tty)) | |
53c5ee2c | 469 | ldata->column++; |
a59c0d6f | 470 | } |
a88a69c9 | 471 | break; |
1da177e4 | 472 | } |
a88a69c9 | 473 | |
f34d7a5b | 474 | tty_put_char(tty, c); |
a88a69c9 JP |
475 | return 1; |
476 | } | |
477 | ||
478 | /** | |
479 | * process_output - output post processor | |
480 | * @c: character (or partial unicode symbol) | |
481 | * @tty: terminal device | |
482 | * | |
ee5aa7b8 JP |
483 | * Output one character with OPOST processing. |
484 | * Returns -1 when the output device is full and the character | |
485 | * must be retried. | |
a88a69c9 JP |
486 | * |
487 | * Locking: output_lock to protect column state and space left | |
488 | * (also, this is called from n_tty_write under the | |
489 | * tty layer write lock) | |
490 | */ | |
491 | ||
492 | static int process_output(unsigned char c, struct tty_struct *tty) | |
493 | { | |
bddc7152 | 494 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
495 | int space, retval; |
496 | ||
bddc7152 | 497 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
498 | |
499 | space = tty_write_room(tty); | |
500 | retval = do_output_char(c, tty, space); | |
501 | ||
bddc7152 | 502 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
503 | if (retval < 0) |
504 | return -1; | |
505 | else | |
506 | return 0; | |
1da177e4 LT |
507 | } |
508 | ||
509 | /** | |
a88a69c9 | 510 | * process_output_block - block post processor |
1da177e4 | 511 | * @tty: terminal device |
ee5aa7b8 JP |
512 | * @buf: character buffer |
513 | * @nr: number of bytes to output | |
514 | * | |
515 | * Output a block of characters with OPOST processing. | |
516 | * Returns the number of characters output. | |
1da177e4 LT |
517 | * |
518 | * This path is used to speed up block console writes, among other | |
519 | * things when processing blocks of output data. It handles only | |
520 | * the simple cases normally found and helps to generate blocks of | |
521 | * symbols for the console driver and thus improve performance. | |
522 | * | |
a88a69c9 JP |
523 | * Locking: output_lock to protect column state and space left |
524 | * (also, this is called from n_tty_write under the | |
525 | * tty layer write lock) | |
1da177e4 | 526 | */ |
4edf1827 | 527 | |
a88a69c9 JP |
528 | static ssize_t process_output_block(struct tty_struct *tty, |
529 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 530 | { |
53c5ee2c | 531 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 532 | int space; |
bbd20759 | 533 | int i; |
1da177e4 LT |
534 | const unsigned char *cp; |
535 | ||
bddc7152 | 536 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 537 | |
f34d7a5b | 538 | space = tty_write_room(tty); |
300a6204 | 539 | if (!space) { |
bddc7152 | 540 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 541 | return 0; |
a88a69c9 | 542 | } |
1da177e4 LT |
543 | if (nr > space) |
544 | nr = space; | |
545 | ||
546 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
547 | unsigned char c = *cp; |
548 | ||
549 | switch (c) { | |
1da177e4 LT |
550 | case '\n': |
551 | if (O_ONLRET(tty)) | |
53c5ee2c | 552 | ldata->column = 0; |
1da177e4 LT |
553 | if (O_ONLCR(tty)) |
554 | goto break_out; | |
ba2e68ac | 555 | ldata->canon_column = ldata->column; |
1da177e4 LT |
556 | break; |
557 | case '\r': | |
53c5ee2c | 558 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
559 | goto break_out; |
560 | if (O_OCRNL(tty)) | |
561 | goto break_out; | |
ba2e68ac | 562 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
563 | break; |
564 | case '\t': | |
565 | goto break_out; | |
566 | case '\b': | |
53c5ee2c JS |
567 | if (ldata->column > 0) |
568 | ldata->column--; | |
1da177e4 LT |
569 | break; |
570 | default: | |
a59c0d6f JP |
571 | if (!iscntrl(c)) { |
572 | if (O_OLCUC(tty)) | |
573 | goto break_out; | |
574 | if (!is_continuation(c, tty)) | |
53c5ee2c | 575 | ldata->column++; |
a59c0d6f | 576 | } |
1da177e4 LT |
577 | break; |
578 | } | |
579 | } | |
580 | break_out: | |
f34d7a5b | 581 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 582 | |
bddc7152 | 583 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
584 | return i; |
585 | } | |
586 | ||
a88a69c9 JP |
587 | /** |
588 | * process_echoes - write pending echo characters | |
589 | * @tty: terminal device | |
590 | * | |
591 | * Write previously buffered echo (and other ldisc-generated) | |
592 | * characters to the tty. | |
593 | * | |
594 | * Characters generated by the ldisc (including echoes) need to | |
595 | * be buffered because the driver's write buffer can fill during | |
596 | * heavy program output. Echoing straight to the driver will | |
597 | * often fail under these conditions, causing lost characters and | |
598 | * resulting mismatches of ldisc state information. | |
599 | * | |
600 | * Since the ldisc state must represent the characters actually sent | |
601 | * to the driver at the time of the write, operations like certain | |
602 | * changes in column state are also saved in the buffer and executed | |
603 | * here. | |
604 | * | |
605 | * A circular fifo buffer is used so that the most recent characters | |
606 | * are prioritized. Also, when control characters are echoed with a | |
607 | * prefixed "^", the pair is treated atomically and thus not separated. | |
608 | * | |
019ebdf9 | 609 | * Locking: callers must hold output_lock |
a88a69c9 JP |
610 | */ |
611 | ||
bc5b1ec5 | 612 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 613 | { |
53c5ee2c | 614 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 615 | int space, old_space; |
addaebcc | 616 | size_t tail; |
a88a69c9 | 617 | unsigned char c; |
a88a69c9 | 618 | |
bc5b1ec5 | 619 | old_space = space = tty_write_room(tty); |
a88a69c9 | 620 | |
addaebcc | 621 | tail = ldata->echo_tail; |
29c7c5ca | 622 | while (ldata->echo_commit != tail) { |
addaebcc | 623 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
624 | if (c == ECHO_OP_START) { |
625 | unsigned char op; | |
a88a69c9 JP |
626 | int no_space_left = 0; |
627 | ||
628 | /* | |
629 | * If the buffer byte is the start of a multi-byte | |
630 | * operation, get the next byte, which is either the | |
631 | * op code or a control character value. | |
632 | */ | |
addaebcc | 633 | op = echo_buf(ldata, tail + 1); |
300a6204 | 634 | |
a88a69c9 JP |
635 | switch (op) { |
636 | unsigned int num_chars, num_bs; | |
637 | ||
638 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 639 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
640 | |
641 | /* | |
642 | * Determine how many columns to go back | |
643 | * in order to erase the tab. | |
644 | * This depends on the number of columns | |
645 | * used by other characters within the tab | |
646 | * area. If this (modulo 8) count is from | |
647 | * the start of input rather than from a | |
648 | * previous tab, we offset by canon column. | |
649 | * Otherwise, tab spacing is normal. | |
650 | */ | |
651 | if (!(num_chars & 0x80)) | |
ba2e68ac | 652 | num_chars += ldata->canon_column; |
a88a69c9 JP |
653 | num_bs = 8 - (num_chars & 7); |
654 | ||
655 | if (num_bs > space) { | |
656 | no_space_left = 1; | |
657 | break; | |
658 | } | |
659 | space -= num_bs; | |
660 | while (num_bs--) { | |
661 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
662 | if (ldata->column > 0) |
663 | ldata->column--; | |
a88a69c9 | 664 | } |
addaebcc | 665 | tail += 3; |
a88a69c9 JP |
666 | break; |
667 | ||
668 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 669 | ldata->canon_column = ldata->column; |
addaebcc | 670 | tail += 2; |
a88a69c9 JP |
671 | break; |
672 | ||
673 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
674 | if (ldata->column > 0) |
675 | ldata->column--; | |
addaebcc | 676 | tail += 2; |
a88a69c9 JP |
677 | break; |
678 | ||
679 | case ECHO_OP_START: | |
680 | /* This is an escaped echo op start code */ | |
681 | if (!space) { | |
682 | no_space_left = 1; | |
683 | break; | |
684 | } | |
685 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 686 | ldata->column++; |
a88a69c9 | 687 | space--; |
addaebcc | 688 | tail += 2; |
a88a69c9 JP |
689 | break; |
690 | ||
691 | default: | |
a88a69c9 | 692 | /* |
62b26358 JP |
693 | * If the op is not a special byte code, |
694 | * it is a ctrl char tagged to be echoed | |
695 | * as "^X" (where X is the letter | |
696 | * representing the control char). | |
697 | * Note that we must ensure there is | |
698 | * enough space for the whole ctrl pair. | |
699 | * | |
a88a69c9 | 700 | */ |
62b26358 JP |
701 | if (space < 2) { |
702 | no_space_left = 1; | |
703 | break; | |
704 | } | |
705 | tty_put_char(tty, '^'); | |
706 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 707 | ldata->column += 2; |
62b26358 | 708 | space -= 2; |
addaebcc | 709 | tail += 2; |
a88a69c9 JP |
710 | } |
711 | ||
712 | if (no_space_left) | |
713 | break; | |
714 | } else { | |
582f5590 | 715 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
716 | int retval = do_output_char(c, tty, space); |
717 | if (retval < 0) | |
718 | break; | |
719 | space -= retval; | |
720 | } else { | |
721 | if (!space) | |
722 | break; | |
723 | tty_put_char(tty, c); | |
724 | space -= 1; | |
725 | } | |
addaebcc | 726 | tail += 1; |
a88a69c9 | 727 | } |
a88a69c9 JP |
728 | } |
729 | ||
cbfd0340 PH |
730 | /* If the echo buffer is nearly full (so that the possibility exists |
731 | * of echo overrun before the next commit), then discard enough | |
732 | * data at the tail to prevent a subsequent overrun */ | |
733 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 734 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 735 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
736 | tail += 3; |
737 | else | |
738 | tail += 2; | |
739 | } else | |
740 | tail++; | |
741 | } | |
742 | ||
addaebcc | 743 | ldata->echo_tail = tail; |
bc5b1ec5 | 744 | return old_space - space; |
019ebdf9 PH |
745 | } |
746 | ||
747 | static void commit_echoes(struct tty_struct *tty) | |
748 | { | |
749 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 750 | size_t nr, old, echoed; |
cbfd0340 PH |
751 | size_t head; |
752 | ||
753 | head = ldata->echo_head; | |
1075a6e2 | 754 | ldata->echo_mark = head; |
cbfd0340 PH |
755 | old = ldata->echo_commit - ldata->echo_tail; |
756 | ||
757 | /* Process committed echoes if the accumulated # of bytes | |
758 | * is over the threshold (and try again each time another | |
759 | * block is accumulated) */ | |
760 | nr = head - ldata->echo_tail; | |
761 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
762 | return; | |
a88a69c9 | 763 | |
019ebdf9 | 764 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 765 | ldata->echo_commit = head; |
bc5b1ec5 | 766 | echoed = __process_echoes(tty); |
bddc7152 | 767 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 768 | |
bc5b1ec5 | 769 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
770 | tty->ops->flush_chars(tty); |
771 | } | |
772 | ||
019ebdf9 | 773 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
774 | { |
775 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 776 | size_t echoed; |
17bd7907 | 777 | |
e2613be5 | 778 | if (ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
779 | return; |
780 | ||
781 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 782 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 783 | echoed = __process_echoes(tty); |
019ebdf9 PH |
784 | mutex_unlock(&ldata->output_lock); |
785 | ||
bc5b1ec5 | 786 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 787 | tty->ops->flush_chars(tty); |
17bd7907 PH |
788 | } |
789 | ||
1075a6e2 | 790 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
791 | static void flush_echoes(struct tty_struct *tty) |
792 | { | |
793 | struct n_tty_data *ldata = tty->disc_data; | |
794 | ||
39434abd PH |
795 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
796 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
797 | return; |
798 | ||
799 | mutex_lock(&ldata->output_lock); | |
800 | ldata->echo_commit = ldata->echo_head; | |
801 | __process_echoes(tty); | |
802 | mutex_unlock(&ldata->output_lock); | |
803 | } | |
804 | ||
a88a69c9 JP |
805 | /** |
806 | * add_echo_byte - add a byte to the echo buffer | |
807 | * @c: unicode byte to echo | |
57c94121 | 808 | * @ldata: n_tty data |
a88a69c9 JP |
809 | * |
810 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
811 | */ |
812 | ||
cbfd0340 | 813 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 814 | { |
addaebcc | 815 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
816 | } |
817 | ||
818 | /** | |
819 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 820 | * @ldata: n_tty data |
a88a69c9 JP |
821 | * |
822 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
823 | */ |
824 | ||
57c94121 | 825 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 826 | { |
57c94121 JS |
827 | add_echo_byte(ECHO_OP_START, ldata); |
828 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
829 | } |
830 | ||
831 | /** | |
832 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 833 | * @ldata: n_tty data |
a88a69c9 JP |
834 | * |
835 | * Add an operation to the echo buffer to set the canon column | |
836 | * to the current column. | |
a88a69c9 JP |
837 | */ |
838 | ||
57c94121 | 839 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 840 | { |
57c94121 JS |
841 | add_echo_byte(ECHO_OP_START, ldata); |
842 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
843 | } |
844 | ||
845 | /** | |
846 | * echo_erase_tab - add operation to erase a tab | |
847 | * @num_chars: number of character columns already used | |
848 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 849 | * @ldata: n_tty data |
a88a69c9 JP |
850 | * |
851 | * Add an operation to the echo buffer to erase a tab. | |
852 | * | |
853 | * Called by the eraser function, which knows how many character | |
854 | * columns have been used since either a previous tab or the start | |
855 | * of input. This information will be used later, along with | |
856 | * canon column (if applicable), to go back the correct number | |
857 | * of columns. | |
a88a69c9 JP |
858 | */ |
859 | ||
860 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 861 | struct n_tty_data *ldata) |
a88a69c9 | 862 | { |
57c94121 JS |
863 | add_echo_byte(ECHO_OP_START, ldata); |
864 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
865 | |
866 | /* We only need to know this modulo 8 (tab spacing) */ | |
867 | num_chars &= 7; | |
868 | ||
869 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
870 | if (after_tab) | |
871 | num_chars |= 0x80; | |
300a6204 | 872 | |
57c94121 | 873 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
874 | } |
875 | ||
876 | /** | |
877 | * echo_char_raw - echo a character raw | |
878 | * @c: unicode byte to echo | |
879 | * @tty: terminal device | |
880 | * | |
881 | * Echo user input back onto the screen. This must be called only when | |
882 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
883 | * | |
884 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
885 | */ |
886 | ||
57c94121 | 887 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 888 | { |
a88a69c9 | 889 | if (c == ECHO_OP_START) { |
57c94121 JS |
890 | add_echo_byte(ECHO_OP_START, ldata); |
891 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 892 | } else { |
57c94121 | 893 | add_echo_byte(c, ldata); |
a88a69c9 | 894 | } |
a88a69c9 | 895 | } |
1da177e4 | 896 | |
1da177e4 | 897 | /** |
a88a69c9 | 898 | * echo_char - echo a character |
1da177e4 LT |
899 | * @c: unicode byte to echo |
900 | * @tty: terminal device | |
901 | * | |
4edf1827 | 902 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 903 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 904 | * |
62b26358 JP |
905 | * This variant tags control characters to be echoed as "^X" |
906 | * (where X is the letter representing the control char). | |
1da177e4 LT |
907 | */ |
908 | ||
909 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
910 | { | |
bddc7152 JS |
911 | struct n_tty_data *ldata = tty->disc_data; |
912 | ||
a88a69c9 | 913 | if (c == ECHO_OP_START) { |
57c94121 JS |
914 | add_echo_byte(ECHO_OP_START, ldata); |
915 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 916 | } else { |
62b26358 | 917 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
918 | add_echo_byte(ECHO_OP_START, ldata); |
919 | add_echo_byte(c, ldata); | |
a88a69c9 | 920 | } |
1da177e4 LT |
921 | } |
922 | ||
17b82060 | 923 | /** |
a88a69c9 | 924 | * finish_erasing - complete erase |
57c94121 | 925 | * @ldata: n_tty data |
17b82060 | 926 | */ |
a88a69c9 | 927 | |
57c94121 | 928 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 929 | { |
53c5ee2c | 930 | if (ldata->erasing) { |
57c94121 | 931 | echo_char_raw('/', ldata); |
53c5ee2c | 932 | ldata->erasing = 0; |
1da177e4 LT |
933 | } |
934 | } | |
935 | ||
936 | /** | |
937 | * eraser - handle erase function | |
938 | * @c: character input | |
939 | * @tty: terminal device | |
940 | * | |
3a4fa0a2 | 941 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
942 | * present in the stream from the driver layer. Handles the complexities |
943 | * of UTF-8 multibyte symbols. | |
17b82060 | 944 | * |
6d76bd26 PH |
945 | * n_tty_receive_buf()/producer path: |
946 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 947 | */ |
4edf1827 | 948 | |
1da177e4 LT |
949 | static void eraser(unsigned char c, struct tty_struct *tty) |
950 | { | |
53c5ee2c | 951 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 952 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
953 | size_t head; |
954 | size_t cnt; | |
955 | int seen_alnums; | |
1da177e4 | 956 | |
ba2e68ac | 957 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 958 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
959 | return; |
960 | } | |
961 | if (c == ERASE_CHAR(tty)) | |
962 | kill_type = ERASE; | |
963 | else if (c == WERASE_CHAR(tty)) | |
964 | kill_type = WERASE; | |
965 | else { | |
966 | if (!L_ECHO(tty)) { | |
ba2e68ac | 967 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
968 | return; |
969 | } | |
970 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 971 | ldata->read_head = ldata->canon_head; |
57c94121 | 972 | finish_erasing(ldata); |
1da177e4 LT |
973 | echo_char(KILL_CHAR(tty), tty); |
974 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
975 | if (L_ECHOK(tty)) | |
57c94121 | 976 | echo_char_raw('\n', ldata); |
1da177e4 LT |
977 | return; |
978 | } | |
979 | kill_type = KILL; | |
980 | } | |
981 | ||
982 | seen_alnums = 0; | |
ba2e68ac JS |
983 | while (ldata->read_head != ldata->canon_head) { |
984 | head = ldata->read_head; | |
1da177e4 LT |
985 | |
986 | /* erase a single possibly multibyte character */ | |
987 | do { | |
bc5a5e3f PH |
988 | head--; |
989 | c = read_buf(ldata, head); | |
ba2e68ac | 990 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
991 | |
992 | /* do not partially erase */ | |
993 | if (is_continuation(c, tty)) | |
994 | break; | |
995 | ||
996 | if (kill_type == WERASE) { | |
997 | /* Equivalent to BSD's ALTWERASE. */ | |
998 | if (isalnum(c) || c == '_') | |
999 | seen_alnums++; | |
1000 | else if (seen_alnums) | |
1001 | break; | |
1002 | } | |
bc5a5e3f | 1003 | cnt = ldata->read_head - head; |
ba2e68ac | 1004 | ldata->read_head = head; |
1da177e4 LT |
1005 | if (L_ECHO(tty)) { |
1006 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1007 | if (!ldata->erasing) { |
57c94121 | 1008 | echo_char_raw('\\', ldata); |
53c5ee2c | 1009 | ldata->erasing = 1; |
1da177e4 LT |
1010 | } |
1011 | /* if cnt > 1, output a multi-byte character */ | |
1012 | echo_char(c, tty); | |
1013 | while (--cnt > 0) { | |
bc5a5e3f PH |
1014 | head++; |
1015 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1016 | echo_move_back_col(ldata); |
1da177e4 LT |
1017 | } |
1018 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1019 | echo_char(ERASE_CHAR(tty), tty); | |
1020 | } else if (c == '\t') { | |
a88a69c9 JP |
1021 | unsigned int num_chars = 0; |
1022 | int after_tab = 0; | |
bc5a5e3f | 1023 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1024 | |
1025 | /* | |
1026 | * Count the columns used for characters | |
1027 | * since the start of input or after a | |
1028 | * previous tab. | |
1029 | * This info is used to go back the correct | |
1030 | * number of columns. | |
1031 | */ | |
ba2e68ac | 1032 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1033 | tail--; |
1034 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1035 | if (c == '\t') { |
1036 | after_tab = 1; | |
1037 | break; | |
300a6204 | 1038 | } else if (iscntrl(c)) { |
1da177e4 | 1039 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1040 | num_chars += 2; |
1041 | } else if (!is_continuation(c, tty)) { | |
1042 | num_chars++; | |
1043 | } | |
1da177e4 | 1044 | } |
57c94121 | 1045 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1046 | } else { |
1047 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1048 | echo_char_raw('\b', ldata); |
1049 | echo_char_raw(' ', ldata); | |
1050 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1051 | } |
1052 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1053 | echo_char_raw('\b', ldata); |
1054 | echo_char_raw(' ', ldata); | |
1055 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1056 | } |
1057 | } | |
1058 | } | |
1059 | if (kill_type == ERASE) | |
1060 | break; | |
1061 | } | |
ba2e68ac | 1062 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1063 | finish_erasing(ldata); |
1da177e4 LT |
1064 | } |
1065 | ||
1066 | /** | |
1067 | * isig - handle the ISIG optio | |
1068 | * @sig: signal | |
1069 | * @tty: terminal | |
1da177e4 | 1070 | * |
8c985d18 PH |
1071 | * Called when a signal is being sent due to terminal input. |
1072 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1073 | * |
d2b6f447 PH |
1074 | * Performs input and output flush if !NOFLSH. In this context, the echo |
1075 | * buffer is 'output'. The signal is processed first to alert any current | |
1076 | * readers or writers to discontinue and exit their i/o loops. | |
1077 | * | |
8c985d18 | 1078 | * Locking: ctrl_lock |
1da177e4 | 1079 | */ |
4edf1827 | 1080 | |
3b19e032 | 1081 | static void __isig(int sig, struct tty_struct *tty) |
1da177e4 | 1082 | { |
8c985d18 PH |
1083 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1084 | if (tty_pgrp) { | |
1085 | kill_pgrp(tty_pgrp, sig, 1); | |
1086 | put_pid(tty_pgrp); | |
1da177e4 | 1087 | } |
3b19e032 | 1088 | } |
d2b6f447 | 1089 | |
3b19e032 PH |
1090 | static void isig(int sig, struct tty_struct *tty) |
1091 | { | |
1092 | struct n_tty_data *ldata = tty->disc_data; | |
1093 | ||
1094 | if (L_NOFLSH(tty)) { | |
1095 | /* signal only */ | |
1096 | __isig(sig, tty); | |
1097 | ||
1098 | } else { /* signal and flush */ | |
d2b6f447 PH |
1099 | up_read(&tty->termios_rwsem); |
1100 | down_write(&tty->termios_rwsem); | |
1101 | ||
3b19e032 PH |
1102 | __isig(sig, tty); |
1103 | ||
d2b6f447 PH |
1104 | /* clear echo buffer */ |
1105 | mutex_lock(&ldata->output_lock); | |
1106 | ldata->echo_head = ldata->echo_tail = 0; | |
1107 | ldata->echo_mark = ldata->echo_commit = 0; | |
1108 | mutex_unlock(&ldata->output_lock); | |
1109 | ||
1110 | /* clear output buffer */ | |
1111 | tty_driver_flush_buffer(tty); | |
1112 | ||
1113 | /* clear input buffer */ | |
1114 | reset_buffer_flags(tty->disc_data); | |
1115 | ||
1116 | /* notify pty master of flush */ | |
1117 | if (tty->link) | |
1118 | n_tty_packet_mode_flush(tty); | |
1119 | ||
1120 | up_write(&tty->termios_rwsem); | |
1121 | down_read(&tty->termios_rwsem); | |
1122 | } | |
1da177e4 LT |
1123 | } |
1124 | ||
1125 | /** | |
1126 | * n_tty_receive_break - handle break | |
1127 | * @tty: terminal | |
1128 | * | |
1129 | * An RS232 break event has been hit in the incoming bitstream. This | |
1130 | * can cause a variety of events depending upon the termios settings. | |
1131 | * | |
6d76bd26 PH |
1132 | * n_tty_receive_buf()/producer path: |
1133 | * caller holds non-exclusive termios_rwsem | |
6d76bd26 PH |
1134 | * |
1135 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1136 | */ |
4edf1827 | 1137 | |
4b293492 | 1138 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1139 | { |
57c94121 JS |
1140 | struct n_tty_data *ldata = tty->disc_data; |
1141 | ||
1da177e4 LT |
1142 | if (I_IGNBRK(tty)) |
1143 | return; | |
1144 | if (I_BRKINT(tty)) { | |
8c985d18 | 1145 | isig(SIGINT, tty); |
1da177e4 LT |
1146 | return; |
1147 | } | |
1148 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1149 | put_tty_queue('\377', ldata); |
1150 | put_tty_queue('\0', ldata); | |
1da177e4 | 1151 | } |
57c94121 | 1152 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1153 | } |
1154 | ||
1155 | /** | |
1156 | * n_tty_receive_overrun - handle overrun reporting | |
1157 | * @tty: terminal | |
1158 | * | |
1159 | * Data arrived faster than we could process it. While the tty | |
1160 | * driver has flagged this the bits that were missed are gone | |
1161 | * forever. | |
1162 | * | |
1163 | * Called from the receive_buf path so single threaded. Does not | |
1164 | * need locking as num_overrun and overrun_time are function | |
1165 | * private. | |
1166 | */ | |
4edf1827 | 1167 | |
4b293492 | 1168 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1169 | { |
53c5ee2c | 1170 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1171 | |
53c5ee2c JS |
1172 | ldata->num_overrun++; |
1173 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1174 | time_after(ldata->overrun_time, jiffies)) { | |
339f36ba | 1175 | tty_warn(tty, "%d input overrun(s)\n", ldata->num_overrun); |
53c5ee2c JS |
1176 | ldata->overrun_time = jiffies; |
1177 | ldata->num_overrun = 0; | |
1da177e4 LT |
1178 | } |
1179 | } | |
1180 | ||
1181 | /** | |
1182 | * n_tty_receive_parity_error - error notifier | |
1183 | * @tty: terminal device | |
1184 | * @c: character | |
1185 | * | |
1186 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1187 | * the error case if necessary. |
1188 | * | |
1189 | * n_tty_receive_buf()/producer path: | |
1190 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 1191 | */ |
4b293492 | 1192 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1193 | { |
57c94121 JS |
1194 | struct n_tty_data *ldata = tty->disc_data; |
1195 | ||
66528f90 PH |
1196 | if (I_INPCK(tty)) { |
1197 | if (I_IGNPAR(tty)) | |
1198 | return; | |
1199 | if (I_PARMRK(tty)) { | |
1200 | put_tty_queue('\377', ldata); | |
1201 | put_tty_queue('\0', ldata); | |
1202 | put_tty_queue(c, ldata); | |
1203 | } else | |
1204 | put_tty_queue('\0', ldata); | |
1205 | } else | |
57c94121 | 1206 | put_tty_queue(c, ldata); |
1da177e4 LT |
1207 | } |
1208 | ||
b0ac50be PH |
1209 | static void |
1210 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1211 | { | |
d2b6f447 | 1212 | isig(signal, tty); |
b0ac50be PH |
1213 | if (I_IXON(tty)) |
1214 | start_tty(tty); | |
1215 | if (L_ECHO(tty)) { | |
1216 | echo_char(c, tty); | |
1217 | commit_echoes(tty); | |
e2613be5 PH |
1218 | } else |
1219 | process_echoes(tty); | |
b0ac50be PH |
1220 | return; |
1221 | } | |
1222 | ||
1da177e4 LT |
1223 | /** |
1224 | * n_tty_receive_char - perform processing | |
1225 | * @tty: terminal device | |
1226 | * @c: character | |
1227 | * | |
1228 | * Process an individual character of input received from the driver. | |
4edf1827 | 1229 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1230 | * driver above. |
6d76bd26 PH |
1231 | * |
1232 | * n_tty_receive_buf()/producer path: | |
1233 | * caller holds non-exclusive termios_rwsem | |
1234 | * publishes canon_head if canonical mode is active | |
e60d27c4 PH |
1235 | * |
1236 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1237 | */ |
1238 | ||
e60d27c4 | 1239 | static int |
4b1f79c2 | 1240 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1241 | { |
53c5ee2c | 1242 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1243 | |
1da177e4 LT |
1244 | if (I_IXON(tty)) { |
1245 | if (c == START_CHAR(tty)) { | |
1246 | start_tty(tty); | |
e2613be5 | 1247 | process_echoes(tty); |
e60d27c4 | 1248 | return 0; |
1da177e4 LT |
1249 | } |
1250 | if (c == STOP_CHAR(tty)) { | |
1251 | stop_tty(tty); | |
e60d27c4 | 1252 | return 0; |
1da177e4 LT |
1253 | } |
1254 | } | |
575537b3 | 1255 | |
1da177e4 | 1256 | if (L_ISIG(tty)) { |
b0ac50be PH |
1257 | if (c == INTR_CHAR(tty)) { |
1258 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1259 | return 0; |
b0ac50be PH |
1260 | } else if (c == QUIT_CHAR(tty)) { |
1261 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1262 | return 0; |
b0ac50be PH |
1263 | } else if (c == SUSP_CHAR(tty)) { |
1264 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1265 | return 0; |
1da177e4 LT |
1266 | } |
1267 | } | |
575537b3 | 1268 | |
855df3c0 PH |
1269 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1270 | start_tty(tty); | |
1271 | process_echoes(tty); | |
1272 | } | |
1273 | ||
575537b3 JP |
1274 | if (c == '\r') { |
1275 | if (I_IGNCR(tty)) | |
e60d27c4 | 1276 | return 0; |
575537b3 JP |
1277 | if (I_ICRNL(tty)) |
1278 | c = '\n'; | |
1279 | } else if (c == '\n' && I_INLCR(tty)) | |
1280 | c = '\r'; | |
1281 | ||
53c5ee2c | 1282 | if (ldata->icanon) { |
1da177e4 LT |
1283 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1284 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1285 | eraser(c, tty); | |
17bd7907 | 1286 | commit_echoes(tty); |
e60d27c4 | 1287 | return 0; |
1da177e4 LT |
1288 | } |
1289 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1290 | ldata->lnext = 1; |
1da177e4 | 1291 | if (L_ECHO(tty)) { |
57c94121 | 1292 | finish_erasing(ldata); |
1da177e4 | 1293 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1294 | echo_char_raw('^', ldata); |
1295 | echo_char_raw('\b', ldata); | |
17bd7907 | 1296 | commit_echoes(tty); |
1da177e4 LT |
1297 | } |
1298 | } | |
e60d27c4 | 1299 | return 1; |
1da177e4 | 1300 | } |
e60d27c4 | 1301 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1302 | size_t tail = ldata->canon_head; |
1da177e4 | 1303 | |
57c94121 | 1304 | finish_erasing(ldata); |
1da177e4 | 1305 | echo_char(c, tty); |
57c94121 | 1306 | echo_char_raw('\n', ldata); |
ba2e68ac | 1307 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1308 | echo_char(read_buf(ldata, tail), tty); |
1309 | tail++; | |
1da177e4 | 1310 | } |
17bd7907 | 1311 | commit_echoes(tty); |
e60d27c4 | 1312 | return 0; |
1da177e4 LT |
1313 | } |
1314 | if (c == '\n') { | |
acc71bba | 1315 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1316 | echo_char_raw('\n', ldata); |
17bd7907 | 1317 | commit_echoes(tty); |
1da177e4 LT |
1318 | } |
1319 | goto handle_newline; | |
1320 | } | |
1321 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1322 | c = __DISABLED_CHAR; |
1323 | goto handle_newline; | |
1324 | } | |
1325 | if ((c == EOL_CHAR(tty)) || | |
1326 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1327 | /* | |
1328 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1329 | */ | |
1330 | if (L_ECHO(tty)) { | |
1da177e4 | 1331 | /* Record the column of first canon char. */ |
ba2e68ac | 1332 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1333 | echo_set_canon_col(ldata); |
1da177e4 | 1334 | echo_char(c, tty); |
17bd7907 | 1335 | commit_echoes(tty); |
1da177e4 LT |
1336 | } |
1337 | /* | |
1338 | * XXX does PARMRK doubling happen for | |
1339 | * EOL_CHAR and EOL2_CHAR? | |
1340 | */ | |
001ba923 | 1341 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
57c94121 | 1342 | put_tty_queue(c, ldata); |
1da177e4 | 1343 | |
4edf1827 | 1344 | handle_newline: |
bc5a5e3f | 1345 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1346 | put_tty_queue(c, ldata); |
70aca71f | 1347 | smp_store_release(&ldata->canon_head, ldata->read_head); |
1da177e4 | 1348 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
e81107d4 | 1349 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
e60d27c4 | 1350 | return 0; |
1da177e4 LT |
1351 | } |
1352 | } | |
4edf1827 | 1353 | |
acc71bba | 1354 | if (L_ECHO(tty)) { |
57c94121 | 1355 | finish_erasing(ldata); |
1da177e4 | 1356 | if (c == '\n') |
57c94121 | 1357 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1358 | else { |
1359 | /* Record the column of first canon char. */ | |
ba2e68ac | 1360 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1361 | echo_set_canon_col(ldata); |
1da177e4 LT |
1362 | echo_char(c, tty); |
1363 | } | |
17bd7907 | 1364 | commit_echoes(tty); |
1da177e4 LT |
1365 | } |
1366 | ||
001ba923 PH |
1367 | /* PARMRK doubling check */ |
1368 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
57c94121 | 1369 | put_tty_queue(c, ldata); |
1da177e4 | 1370 | |
57c94121 | 1371 | put_tty_queue(c, ldata); |
e60d27c4 | 1372 | return 0; |
4edf1827 | 1373 | } |
1da177e4 | 1374 | |
e60d27c4 PH |
1375 | static inline void |
1376 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1377 | { |
1378 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1379 | |
e60d27c4 PH |
1380 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1381 | start_tty(tty); | |
1382 | process_echoes(tty); | |
1383 | } | |
1384 | if (L_ECHO(tty)) { | |
1385 | finish_erasing(ldata); | |
1386 | /* Record the column of first canon char. */ | |
1387 | if (ldata->canon_head == ldata->read_head) | |
1388 | echo_set_canon_col(ldata); | |
1389 | echo_char(c, tty); | |
1390 | commit_echoes(tty); | |
4b1f79c2 | 1391 | } |
001ba923 PH |
1392 | /* PARMRK doubling check */ |
1393 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
e60d27c4 PH |
1394 | put_tty_queue(c, ldata); |
1395 | put_tty_queue(c, ldata); | |
1396 | } | |
4b1f79c2 | 1397 | |
eb3e4668 | 1398 | static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
e60d27c4 PH |
1399 | { |
1400 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1401 | } |
1402 | ||
7de971b0 PH |
1403 | static inline void |
1404 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1405 | { | |
1406 | struct n_tty_data *ldata = tty->disc_data; | |
1407 | ||
e60d27c4 PH |
1408 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1409 | start_tty(tty); | |
1410 | process_echoes(tty); | |
7de971b0 | 1411 | } |
e60d27c4 PH |
1412 | if (L_ECHO(tty)) { |
1413 | finish_erasing(ldata); | |
1414 | /* Record the column of first canon char. */ | |
1415 | if (ldata->canon_head == ldata->read_head) | |
1416 | echo_set_canon_col(ldata); | |
1417 | echo_char(c, tty); | |
1418 | commit_echoes(tty); | |
1419 | } | |
1420 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1421 | } |
1422 | ||
8dc4b25d | 1423 | static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) |
ad0cc7ba PH |
1424 | { |
1425 | if (I_ISTRIP(tty)) | |
1426 | c &= 0x7f; | |
1427 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1428 | c = tolower(c); | |
1429 | ||
1430 | if (I_IXON(tty)) { | |
1431 | if (c == STOP_CHAR(tty)) | |
1432 | stop_tty(tty); | |
1433 | else if (c == START_CHAR(tty) || | |
1434 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1435 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1436 | c != SUSP_CHAR(tty))) { | |
1437 | start_tty(tty); | |
1438 | process_echoes(tty); | |
1439 | } | |
1440 | } | |
1441 | } | |
1442 | ||
d2f8d7ab PH |
1443 | static void |
1444 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1445 | { | |
d2f8d7ab PH |
1446 | switch (flag) { |
1447 | case TTY_BREAK: | |
1448 | n_tty_receive_break(tty); | |
1449 | break; | |
1450 | case TTY_PARITY: | |
1451 | case TTY_FRAME: | |
1452 | n_tty_receive_parity_error(tty, c); | |
1453 | break; | |
1454 | case TTY_OVERRUN: | |
1455 | n_tty_receive_overrun(tty); | |
1456 | break; | |
1457 | default: | |
339f36ba | 1458 | tty_err(tty, "unknown flag %d\n", flag); |
d2f8d7ab PH |
1459 | break; |
1460 | } | |
1461 | } | |
1462 | ||
e60d27c4 PH |
1463 | static void |
1464 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1465 | { | |
1466 | struct n_tty_data *ldata = tty->disc_data; | |
1467 | ||
1468 | ldata->lnext = 0; | |
1469 | if (likely(flag == TTY_NORMAL)) { | |
1470 | if (I_ISTRIP(tty)) | |
1471 | c &= 0x7f; | |
1472 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1473 | c = tolower(c); | |
1474 | n_tty_receive_char(tty, c); | |
1475 | } else | |
1476 | n_tty_receive_char_flagged(tty, c, flag); | |
1477 | } | |
1478 | ||
4a23a4df PH |
1479 | static void |
1480 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1481 | char *fp, int count) | |
1482 | { | |
1483 | struct n_tty_data *ldata = tty->disc_data; | |
1484 | size_t n, head; | |
1485 | ||
1486 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1487 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1488 | memcpy(read_buf_addr(ldata, head), cp, n); |
1489 | ldata->read_head += n; | |
1490 | cp += n; | |
1491 | count -= n; | |
1492 | ||
1493 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1494 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1495 | memcpy(read_buf_addr(ldata, head), cp, n); |
1496 | ldata->read_head += n; | |
1497 | } | |
1498 | ||
554117bd PH |
1499 | static void |
1500 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1501 | char *fp, int count) | |
1502 | { | |
1503 | struct n_tty_data *ldata = tty->disc_data; | |
1504 | char flag = TTY_NORMAL; | |
1505 | ||
1506 | while (count--) { | |
1507 | if (fp) | |
1508 | flag = *fp++; | |
1509 | if (likely(flag == TTY_NORMAL)) | |
1510 | put_tty_queue(*cp++, ldata); | |
1511 | else | |
1512 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1513 | } | |
1514 | } | |
1515 | ||
ad0cc7ba PH |
1516 | static void |
1517 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1518 | char *fp, int count) | |
1519 | { | |
1520 | char flag = TTY_NORMAL; | |
1521 | ||
1522 | while (count--) { | |
1523 | if (fp) | |
1524 | flag = *fp++; | |
1525 | if (likely(flag == TTY_NORMAL)) | |
1526 | n_tty_receive_char_closing(tty, *cp++); | |
ad0cc7ba PH |
1527 | } |
1528 | } | |
1529 | ||
7d88d637 PH |
1530 | static void |
1531 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1532 | char *fp, int count) |
1533 | { | |
1534 | struct n_tty_data *ldata = tty->disc_data; | |
1535 | char flag = TTY_NORMAL; | |
1536 | ||
1537 | while (count--) { | |
1538 | if (fp) | |
1539 | flag = *fp++; | |
1540 | if (likely(flag == TTY_NORMAL)) { | |
1541 | unsigned char c = *cp++; | |
1542 | ||
1543 | if (I_ISTRIP(tty)) | |
1544 | c &= 0x7f; | |
1545 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1546 | c = tolower(c); | |
1547 | if (L_EXTPROC(tty)) { | |
1548 | put_tty_queue(c, ldata); | |
1549 | continue; | |
1550 | } | |
e60d27c4 PH |
1551 | if (!test_bit(c, ldata->char_map)) |
1552 | n_tty_receive_char_inline(tty, c); | |
1553 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1554 | if (fp) | |
1555 | flag = *fp++; | |
1556 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1557 | count--; | |
1558 | } | |
6baad008 PH |
1559 | } else |
1560 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1561 | } | |
1562 | } | |
1563 | ||
1564 | static void | |
1565 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1566 | char *fp, int count) | |
7d88d637 | 1567 | { |
e60d27c4 | 1568 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1569 | char flag = TTY_NORMAL; |
1570 | ||
1571 | while (count--) { | |
1572 | if (fp) | |
1573 | flag = *fp++; | |
e60d27c4 PH |
1574 | if (likely(flag == TTY_NORMAL)) { |
1575 | unsigned char c = *cp++; | |
1576 | ||
1577 | if (!test_bit(c, ldata->char_map)) | |
1578 | n_tty_receive_char_fast(tty, c); | |
1579 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1580 | if (fp) | |
1581 | flag = *fp++; | |
1582 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1583 | count--; | |
1584 | } | |
1585 | } else | |
7d88d637 PH |
1586 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1587 | } | |
1588 | } | |
1589 | ||
24a89d1c PH |
1590 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1591 | char *fp, int count) | |
1da177e4 | 1592 | { |
53c5ee2c | 1593 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1594 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1595 | |
4a23a4df PH |
1596 | if (ldata->real_raw) |
1597 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1598 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1599 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1600 | else if (tty->closing && !L_EXTPROC(tty)) |
1601 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1602 | else { |
e60d27c4 PH |
1603 | if (ldata->lnext) { |
1604 | char flag = TTY_NORMAL; | |
1605 | ||
1606 | if (fp) | |
1607 | flag = *fp++; | |
1608 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1609 | count--; | |
1610 | } | |
1611 | ||
7de971b0 | 1612 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1613 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1614 | else | |
1615 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1616 | |
1617 | flush_echoes(tty); | |
f34d7a5b AC |
1618 | if (tty->ops->flush_chars) |
1619 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1620 | } |
1621 | ||
70aca71f PH |
1622 | if (ldata->icanon && !L_EXTPROC(tty)) |
1623 | return; | |
1624 | ||
1625 | /* publish read_head to consumer */ | |
1626 | smp_store_release(&ldata->commit_head, ldata->read_head); | |
1627 | ||
33d71363 | 1628 | if (read_cnt(ldata)) { |
1da177e4 | 1629 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
e81107d4 | 1630 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 | 1631 | } |
1da177e4 LT |
1632 | } |
1633 | ||
fb5ef9e7 PH |
1634 | /** |
1635 | * n_tty_receive_buf_common - process input | |
1636 | * @tty: device to receive input | |
1637 | * @cp: input chars | |
1638 | * @fp: flags for each char (if NULL, all chars are TTY_NORMAL) | |
1639 | * @count: number of input chars in @cp | |
1640 | * | |
1641 | * Called by the terminal driver when a block of characters has | |
1642 | * been received. This function must be called from soft contexts | |
1643 | * not from interrupt context. The driver is responsible for making | |
1644 | * calls one at a time and in order (or using flush_to_ldisc) | |
1645 | * | |
1646 | * Returns the # of input chars from @cp which were processed. | |
1647 | * | |
1648 | * In canonical mode, the maximum line length is 4096 chars (including | |
1649 | * the line termination char); lines longer than 4096 chars are | |
1650 | * truncated. After 4095 chars, input data is still processed but | |
1651 | * not stored. Overflow processing ensures the tty can always | |
1652 | * receive more input until at least one line can be read. | |
1653 | * | |
1654 | * In non-canonical mode, the read buffer will only accept 4095 chars; | |
1655 | * this provides the necessary space for a newline char if the input | |
1656 | * mode is switched to canonical. | |
1657 | * | |
1658 | * Note it is possible for the read buffer to _contain_ 4096 chars | |
1659 | * in non-canonical mode: the read buffer could already contain the | |
1660 | * maximum canon line of 4096 chars when the mode is switched to | |
1661 | * non-canonical. | |
1662 | * | |
1663 | * n_tty_receive_buf()/producer path: | |
1664 | * claims non-exclusive termios_rwsem | |
1665 | * publishes commit_head or canon_head | |
1666 | */ | |
5c32d123 PH |
1667 | static int |
1668 | n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, | |
1669 | char *fp, int count, int flow) | |
24a89d1c PH |
1670 | { |
1671 | struct n_tty_data *ldata = tty->disc_data; | |
fb5ef9e7 | 1672 | int room, n, rcvd = 0, overflow; |
24a89d1c | 1673 | |
9356b535 PH |
1674 | down_read(&tty->termios_rwsem); |
1675 | ||
19e2ad6a | 1676 | while (1) { |
70aca71f | 1677 | /* |
06c49f9f PH |
1678 | * When PARMRK is set, each input char may take up to 3 chars |
1679 | * in the read buf; reduce the buffer space avail by 3x | |
70aca71f PH |
1680 | * |
1681 | * If we are doing input canonicalization, and there are no | |
1682 | * pending newlines, let characters through without limit, so | |
1683 | * that erase characters will be handled. Other excess | |
1684 | * characters will be beeped. | |
1685 | * | |
1686 | * paired with store in *_copy_from_read_buf() -- guarantees | |
1687 | * the consumer has loaded the data in read_buf up to the new | |
1688 | * read_tail (so this producer will not overwrite unread data) | |
1689 | */ | |
1690 | size_t tail = smp_load_acquire(&ldata->read_tail); | |
70aca71f | 1691 | |
fb5ef9e7 | 1692 | room = N_TTY_BUF_SIZE - (ldata->read_head - tail); |
70aca71f | 1693 | if (I_PARMRK(tty)) |
fb5ef9e7 PH |
1694 | room = (room + 2) / 3; |
1695 | room--; | |
1696 | if (room <= 0) { | |
1697 | overflow = ldata->icanon && ldata->canon_head == tail; | |
1698 | if (overflow && room < 0) | |
1699 | ldata->read_head--; | |
1700 | room = overflow; | |
1701 | ldata->no_room = flow && !room; | |
1702 | } else | |
1703 | overflow = 0; | |
70aca71f | 1704 | |
19e2ad6a | 1705 | n = min(count, room); |
fb5ef9e7 | 1706 | if (!n) |
19e2ad6a | 1707 | break; |
fb5ef9e7 PH |
1708 | |
1709 | /* ignore parity errors if handling overflow */ | |
1710 | if (!overflow || !fp || *fp != TTY_PARITY) | |
1711 | __receive_buf(tty, cp, fp, n); | |
1712 | ||
19e2ad6a PH |
1713 | cp += n; |
1714 | if (fp) | |
1715 | fp += n; | |
1716 | count -= n; | |
1717 | rcvd += n; | |
4a23a4df | 1718 | } |
24a89d1c | 1719 | |
19e2ad6a | 1720 | tty->receive_room = room; |
fb5ef9e7 PH |
1721 | |
1722 | /* Unthrottle if handling overflow on pty */ | |
1723 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { | |
1724 | if (overflow) { | |
1725 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1726 | tty_unthrottle_safe(tty); | |
1727 | __tty_set_flow_change(tty, 0); | |
1728 | } | |
1729 | } else | |
1730 | n_tty_check_throttle(tty); | |
1731 | ||
9356b535 PH |
1732 | up_read(&tty->termios_rwsem); |
1733 | ||
19e2ad6a | 1734 | return rcvd; |
24a89d1c PH |
1735 | } |
1736 | ||
5c32d123 PH |
1737 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1738 | char *fp, int count) | |
1739 | { | |
1740 | n_tty_receive_buf_common(tty, cp, fp, count, 0); | |
1741 | } | |
1742 | ||
1743 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1744 | char *fp, int count) | |
1745 | { | |
1746 | return n_tty_receive_buf_common(tty, cp, fp, count, 1); | |
1747 | } | |
1748 | ||
1da177e4 LT |
1749 | /** |
1750 | * n_tty_set_termios - termios data changed | |
1751 | * @tty: terminal | |
1752 | * @old: previous data | |
1753 | * | |
1754 | * Called by the tty layer when the user changes termios flags so | |
1755 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1756 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1757 | * guaranteed that this function will not be re-entered or in progress |
1758 | * when the ldisc is closed. | |
17b82060 | 1759 | * |
6a1c0680 | 1760 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1761 | */ |
4edf1827 AC |
1762 | |
1763 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1764 | { |
53c5ee2c | 1765 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1766 | |
c786f74e | 1767 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { |
3fe780b3 | 1768 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1769 | ldata->line_start = ldata->read_tail; |
1770 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1771 | ldata->canon_head = ldata->read_tail; | |
1772 | ldata->push = 0; | |
1773 | } else { | |
1774 | set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), | |
1775 | ldata->read_flags); | |
1776 | ldata->canon_head = ldata->read_head; | |
1777 | ldata->push = 1; | |
1778 | } | |
70aca71f | 1779 | ldata->commit_head = ldata->read_head; |
53c5ee2c | 1780 | ldata->erasing = 0; |
6f9b028a | 1781 | ldata->lnext = 0; |
47afa7a5 AC |
1782 | } |
1783 | ||
53c5ee2c | 1784 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1785 | |
1da177e4 LT |
1786 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1787 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1788 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1789 | I_PARMRK(tty)) { | |
1bb9d562 | 1790 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1791 | |
1792 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1793 | set_bit('\r', ldata->char_map); |
1da177e4 | 1794 | if (I_INLCR(tty)) |
1bb9d562 | 1795 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1796 | |
1797 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1798 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1799 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1800 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1801 | set_bit('\n', ldata->char_map); | |
1802 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1803 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1804 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1805 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1806 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1807 | if (L_ECHO(tty)) |
1808 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1809 | ldata->char_map); |
1da177e4 LT |
1810 | } |
1811 | } | |
1812 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1813 | set_bit(START_CHAR(tty), ldata->char_map); |
1814 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1815 | } |
1816 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1817 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1818 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1819 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1820 | } |
1bb9d562 | 1821 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1822 | ldata->raw = 0; |
1823 | ldata->real_raw = 0; | |
1da177e4 | 1824 | } else { |
53c5ee2c | 1825 | ldata->raw = 1; |
1da177e4 LT |
1826 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1827 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1828 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1829 | ldata->real_raw = 1; |
1da177e4 | 1830 | else |
53c5ee2c | 1831 | ldata->real_raw = 0; |
1da177e4 | 1832 | } |
dab73b4e WY |
1833 | /* |
1834 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1835 | * been stopped by STOP_CHAR(tty) before it. | |
1836 | */ | |
e2613be5 | 1837 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { |
dab73b4e | 1838 | start_tty(tty); |
e2613be5 PH |
1839 | process_echoes(tty); |
1840 | } | |
dab73b4e | 1841 | |
f34d7a5b | 1842 | /* The termios change make the tty ready for I/O */ |
e81107d4 KT |
1843 | wake_up_interruptible(&tty->write_wait); |
1844 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1845 | } |
1846 | ||
1847 | /** | |
1848 | * n_tty_close - close the ldisc for this tty | |
1849 | * @tty: device | |
1850 | * | |
4edf1827 AC |
1851 | * Called from the terminal layer when this line discipline is |
1852 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1853 | * discipline change. The function will not be called while other |
1854 | * ldisc methods are in progress. | |
1855 | */ | |
4edf1827 | 1856 | |
1da177e4 LT |
1857 | static void n_tty_close(struct tty_struct *tty) |
1858 | { | |
70ece7a7 JS |
1859 | struct n_tty_data *ldata = tty->disc_data; |
1860 | ||
79901317 PH |
1861 | if (tty->link) |
1862 | n_tty_packet_mode_flush(tty); | |
1863 | ||
20bafb3d | 1864 | vfree(ldata); |
70ece7a7 | 1865 | tty->disc_data = NULL; |
1da177e4 LT |
1866 | } |
1867 | ||
1868 | /** | |
1869 | * n_tty_open - open an ldisc | |
1870 | * @tty: terminal to open | |
1871 | * | |
4edf1827 | 1872 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1873 | * terminal device. Can sleep. Called serialized so that no |
1874 | * other events will occur in parallel. No further open will occur | |
1875 | * until a close. | |
1876 | */ | |
1877 | ||
1878 | static int n_tty_open(struct tty_struct *tty) | |
1879 | { | |
70ece7a7 JS |
1880 | struct n_tty_data *ldata; |
1881 | ||
20bafb3d PH |
1882 | /* Currently a malloc failure here can panic */ |
1883 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1884 | if (!ldata) |
1885 | goto err; | |
1886 | ||
53c5ee2c | 1887 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1888 | mutex_init(&ldata->atomic_read_lock); |
1889 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1890 | |
70ece7a7 | 1891 | tty->disc_data = ldata; |
b66f4fa5 | 1892 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1893 | ldata->column = 0; |
20bafb3d | 1894 | ldata->canon_column = 0; |
20bafb3d PH |
1895 | ldata->num_overrun = 0; |
1896 | ldata->no_room = 0; | |
1897 | ldata->lnext = 0; | |
1da177e4 | 1898 | tty->closing = 0; |
b66f4fa5 PH |
1899 | /* indicate buffer work may resume */ |
1900 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1901 | n_tty_set_termios(tty, NULL); | |
1902 | tty_unthrottle(tty); | |
70ece7a7 | 1903 | |
1da177e4 | 1904 | return 0; |
70ece7a7 | 1905 | err: |
b91939f5 | 1906 | return -ENOMEM; |
1da177e4 LT |
1907 | } |
1908 | ||
eafbe67f | 1909 | static inline int input_available_p(struct tty_struct *tty, int poll) |
1da177e4 | 1910 | { |
53c5ee2c | 1911 | struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1912 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1913 | |
25e8d0ed PH |
1914 | if (ldata->icanon && !L_EXTPROC(tty)) |
1915 | return ldata->canon_head != ldata->read_tail; | |
1916 | else | |
70aca71f | 1917 | return ldata->commit_head - ldata->read_tail >= amt; |
1da177e4 LT |
1918 | } |
1919 | ||
1920 | /** | |
bbd20759 | 1921 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1922 | * @tty: terminal device |
1923 | * @b: user data | |
1924 | * @nr: size of data | |
1925 | * | |
11a96d18 | 1926 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1927 | * ICANON is off; it copies characters straight from the tty queue to |
1928 | * user space directly. It can be profitably called twice; once to | |
1929 | * drain the space from the tail pointer to the (physical) end of the | |
1930 | * buffer, and once to drain the space from the (physical) beginning of | |
1931 | * the buffer to head pointer. | |
1932 | * | |
bddc7152 | 1933 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1934 | * |
6d76bd26 PH |
1935 | * n_tty_read()/consumer path: |
1936 | * caller holds non-exclusive termios_rwsem | |
1937 | * read_tail published | |
1da177e4 | 1938 | */ |
4edf1827 | 1939 | |
33f0f88f | 1940 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1941 | unsigned char __user **b, |
1942 | size_t *nr) | |
1943 | ||
1944 | { | |
53c5ee2c | 1945 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1946 | int retval; |
1947 | size_t n; | |
3fa10cc8 | 1948 | bool is_eof; |
70aca71f | 1949 | size_t head = smp_load_acquire(&ldata->commit_head); |
bc5a5e3f | 1950 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1951 | |
1952 | retval = 0; | |
70aca71f | 1953 | n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail); |
1da177e4 | 1954 | n = min(*nr, n); |
1da177e4 | 1955 | if (n) { |
e661cf70 PH |
1956 | const unsigned char *from = read_buf_addr(ldata, tail); |
1957 | retval = copy_to_user(*b, from, n); | |
1da177e4 | 1958 | n -= retval; |
e661cf70 | 1959 | is_eof = n == 1 && *from == EOF_CHAR(tty); |
309426ae | 1960 | tty_audit_add_data(tty, from, n); |
70aca71f | 1961 | smp_store_release(&ldata->read_tail, ldata->read_tail + n); |
26df6d13 | 1962 | /* Turn single EOF into zero-length read */ |
70aca71f PH |
1963 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && |
1964 | (head == ldata->read_tail)) | |
3fa10cc8 | 1965 | n = 0; |
1da177e4 LT |
1966 | *b += n; |
1967 | *nr -= n; | |
1968 | } | |
1969 | return retval; | |
1970 | } | |
1971 | ||
88bb0de3 | 1972 | /** |
32f13521 | 1973 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1974 | * @tty: terminal device |
1975 | * @b: user data | |
1976 | * @nr: size of data | |
1977 | * | |
1978 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1979 | * it copies one line of input up to and including the line-delimiting |
1980 | * character into the user-space buffer. | |
88bb0de3 | 1981 | * |
4d0ed182 PH |
1982 | * NB: When termios is changed from non-canonical to canonical mode and |
1983 | * the read buffer contains data, n_tty_set_termios() simulates an EOF | |
1984 | * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. | |
1985 | * This causes data already processed as input to be immediately available | |
1986 | * as input although a newline has not been received. | |
1987 | * | |
88bb0de3 | 1988 | * Called under the atomic_read_lock mutex |
6d76bd26 PH |
1989 | * |
1990 | * n_tty_read()/consumer path: | |
1991 | * caller holds non-exclusive termios_rwsem | |
1992 | * read_tail published | |
88bb0de3 PH |
1993 | */ |
1994 | ||
32f13521 PH |
1995 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
1996 | unsigned char __user **b, | |
1997 | size_t *nr) | |
88bb0de3 PH |
1998 | { |
1999 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 2000 | size_t n, size, more, c; |
bc5a5e3f PH |
2001 | size_t eol; |
2002 | size_t tail; | |
2003 | int ret, found = 0; | |
88bb0de3 PH |
2004 | |
2005 | /* N.B. avoid overrun if nr == 0 */ | |
ac8f3bf8 | 2006 | if (!*nr) |
32f13521 | 2007 | return 0; |
88bb0de3 | 2008 | |
ac8f3bf8 PH |
2009 | n = min(*nr + 1, smp_load_acquire(&ldata->canon_head) - ldata->read_tail); |
2010 | ||
bc5a5e3f | 2011 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
2012 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
2013 | ||
bc5a5e3f | 2014 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2015 | __func__, *nr, tail, n, size); |
2016 | ||
2017 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2018 | more = n - (size - tail); | |
2019 | if (eol == N_TTY_BUF_SIZE && more) { | |
2020 | /* scan wrapped without finding set bit */ | |
2021 | eol = find_next_bit(ldata->read_flags, more, 0); | |
b985e9e3 PH |
2022 | found = eol != more; |
2023 | } else | |
2024 | found = eol != size; | |
32f13521 | 2025 | |
c77569d2 | 2026 | n = eol - tail; |
da555db6 MT |
2027 | if (n > N_TTY_BUF_SIZE) |
2028 | n += N_TTY_BUF_SIZE; | |
ac8f3bf8 | 2029 | c = n + found; |
32f13521 | 2030 | |
ac8f3bf8 PH |
2031 | if (!found || read_buf(ldata, eol) != __DISABLED_CHAR) { |
2032 | c = min(*nr, c); | |
2033 | n = c; | |
40d5e090 | 2034 | } |
32f13521 | 2035 | |
679e7c29 PH |
2036 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu tail:%zu more:%zu\n", |
2037 | __func__, eol, found, n, c, tail, more); | |
32f13521 | 2038 | |
679e7c29 | 2039 | ret = tty_copy_to_user(tty, *b, tail, n); |
32f13521 PH |
2040 | if (ret) |
2041 | return -EFAULT; | |
2042 | *b += n; | |
2043 | *nr -= n; | |
2044 | ||
a73d3d69 | 2045 | if (found) |
6d76bd26 | 2046 | clear_bit(eol, ldata->read_flags); |
70aca71f | 2047 | smp_store_release(&ldata->read_tail, ldata->read_tail + c); |
88bb0de3 | 2048 | |
40d5e090 | 2049 | if (found) { |
4d0ed182 PH |
2050 | if (!ldata->push) |
2051 | ldata->line_start = ldata->read_tail; | |
2052 | else | |
2053 | ldata->push = 0; | |
b50819f4 | 2054 | tty_audit_push(); |
40d5e090 | 2055 | } |
ac8f3bf8 | 2056 | return 0; |
88bb0de3 PH |
2057 | } |
2058 | ||
cc4191dc | 2059 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2060 | size_t, loff_t *); |
1da177e4 LT |
2061 | |
2062 | /** | |
2063 | * job_control - check job control | |
2064 | * @tty: tty | |
2065 | * @file: file handle | |
2066 | * | |
2067 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2068 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2069 | * error code if action should be taken. |
04f378b1 | 2070 | * |
01a5e440 PH |
2071 | * Locking: redirected write test is safe |
2072 | * current->signal->tty check is safe | |
2073 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2074 | */ |
4edf1827 | 2075 | |
1da177e4 LT |
2076 | static int job_control(struct tty_struct *tty, struct file *file) |
2077 | { | |
2078 | /* Job control check -- must be done at start and after | |
2079 | every sleep (POSIX.1 7.1.1.4). */ | |
2080 | /* NOTE: not yet done after every sleep pending a thorough | |
2081 | check of the logic of this change. -- jlc */ | |
2082 | /* don't stop on /dev/console */ | |
2812d9e9 | 2083 | if (file->f_op->write == redirected_tty_write) |
01a5e440 PH |
2084 | return 0; |
2085 | ||
2812d9e9 | 2086 | return __tty_check_change(tty, SIGTTIN); |
1da177e4 | 2087 | } |
4edf1827 | 2088 | |
1da177e4 LT |
2089 | |
2090 | /** | |
11a96d18 | 2091 | * n_tty_read - read function for tty |
1da177e4 LT |
2092 | * @tty: tty device |
2093 | * @file: file object | |
2094 | * @buf: userspace buffer pointer | |
2095 | * @nr: size of I/O | |
2096 | * | |
2097 | * Perform reads for the line discipline. We are guaranteed that the | |
2098 | * line discipline will not be closed under us but we may get multiple | |
2099 | * parallel readers and must handle this ourselves. We may also get | |
2100 | * a hangup. Always called in user context, may sleep. | |
2101 | * | |
2102 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2103 | * |
2104 | * n_tty_read()/consumer path: | |
2105 | * claims non-exclusive termios_rwsem | |
2106 | * publishes read_tail | |
1da177e4 | 2107 | */ |
4edf1827 | 2108 | |
11a96d18 | 2109 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2110 | unsigned char __user *buf, size_t nr) |
2111 | { | |
53c5ee2c | 2112 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 2113 | unsigned char __user *b = buf; |
97d9e28d | 2114 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
0f40fbbc | 2115 | int c; |
1da177e4 LT |
2116 | int minimum, time; |
2117 | ssize_t retval = 0; | |
1da177e4 | 2118 | long timeout; |
04f378b1 | 2119 | int packet; |
2c5dc464 | 2120 | size_t tail; |
1da177e4 | 2121 | |
1da177e4 | 2122 | c = job_control(tty, file); |
4edf1827 | 2123 | if (c < 0) |
1da177e4 | 2124 | return c; |
4edf1827 | 2125 | |
aefceaf4 PH |
2126 | /* |
2127 | * Internal serialization of reads. | |
2128 | */ | |
2129 | if (file->f_flags & O_NONBLOCK) { | |
2130 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2131 | return -EAGAIN; | |
2132 | } else { | |
2133 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2134 | return -ERESTARTSYS; | |
2135 | } | |
2136 | ||
9356b535 PH |
2137 | down_read(&tty->termios_rwsem); |
2138 | ||
1da177e4 LT |
2139 | minimum = time = 0; |
2140 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2141 | if (!ldata->icanon) { |
1da177e4 LT |
2142 | minimum = MIN_CHAR(tty); |
2143 | if (minimum) { | |
a6e54319 | 2144 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2145 | } else { |
a6e54319 | 2146 | timeout = (HZ / 10) * TIME_CHAR(tty); |
33d71363 | 2147 | minimum = 1; |
1da177e4 LT |
2148 | } |
2149 | } | |
2150 | ||
04f378b1 | 2151 | packet = tty->packet; |
2c5dc464 | 2152 | tail = ldata->read_tail; |
1da177e4 LT |
2153 | |
2154 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2155 | while (nr) { |
2156 | /* First test for status change. */ | |
04f378b1 | 2157 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2158 | unsigned char cs; |
2159 | if (b != buf) | |
2160 | break; | |
6054c16e | 2161 | spin_lock_irq(&tty->link->ctrl_lock); |
1da177e4 LT |
2162 | cs = tty->link->ctrl_status; |
2163 | tty->link->ctrl_status = 0; | |
6054c16e | 2164 | spin_unlock_irq(&tty->link->ctrl_lock); |
eab25a5c | 2165 | if (put_user(cs, b)) { |
1da177e4 | 2166 | retval = -EFAULT; |
1da177e4 LT |
2167 | break; |
2168 | } | |
eab25a5c | 2169 | b++; |
1da177e4 LT |
2170 | nr--; |
2171 | break; | |
2172 | } | |
4edf1827 | 2173 | |
1da177e4 | 2174 | if (!input_available_p(tty, 0)) { |
52bce7f8 | 2175 | up_read(&tty->termios_rwsem); |
0f40fbbc BB |
2176 | tty_buffer_flush_work(tty->port); |
2177 | down_read(&tty->termios_rwsem); | |
2178 | if (!input_available_p(tty, 0)) { | |
2179 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
2180 | retval = -EIO; | |
2181 | break; | |
2182 | } | |
2183 | if (tty_hung_up_p(file)) | |
2184 | break; | |
2185 | if (!timeout) | |
2186 | break; | |
2187 | if (file->f_flags & O_NONBLOCK) { | |
2188 | retval = -EAGAIN; | |
2189 | break; | |
2190 | } | |
2191 | if (signal_pending(current)) { | |
2192 | retval = -ERESTARTSYS; | |
2193 | break; | |
2194 | } | |
2195 | up_read(&tty->termios_rwsem); | |
9356b535 | 2196 | |
0f40fbbc BB |
2197 | timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, |
2198 | timeout); | |
9356b535 | 2199 | |
0f40fbbc BB |
2200 | down_read(&tty->termios_rwsem); |
2201 | continue; | |
2202 | } | |
1da177e4 LT |
2203 | } |
2204 | ||
53c5ee2c | 2205 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2206 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
ac8f3bf8 | 2207 | if (retval) |
1da177e4 LT |
2208 | break; |
2209 | } else { | |
2210 | int uncopied; | |
95ea90db PH |
2211 | |
2212 | /* Deal with packet mode. */ | |
2213 | if (packet && b == buf) { | |
eab25a5c | 2214 | if (put_user(TIOCPKT_DATA, b)) { |
95ea90db | 2215 | retval = -EFAULT; |
95ea90db PH |
2216 | break; |
2217 | } | |
eab25a5c | 2218 | b++; |
95ea90db PH |
2219 | nr--; |
2220 | } | |
2221 | ||
1da177e4 LT |
2222 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2223 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2224 | if (uncopied) { | |
2225 | retval = -EFAULT; | |
2226 | break; | |
2227 | } | |
2228 | } | |
2229 | ||
6367ca72 | 2230 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2231 | |
2232 | if (b - buf >= minimum) | |
2233 | break; | |
2234 | if (time) | |
2235 | timeout = time; | |
2236 | } | |
2c5dc464 PH |
2237 | if (tail != ldata->read_tail) |
2238 | n_tty_kick_worker(tty); | |
42458f41 PH |
2239 | up_read(&tty->termios_rwsem); |
2240 | ||
1da177e4 | 2241 | remove_wait_queue(&tty->read_wait, &wait); |
aebf0453 PH |
2242 | mutex_unlock(&ldata->atomic_read_lock); |
2243 | ||
40d5e090 PH |
2244 | if (b - buf) |
2245 | retval = b - buf; | |
1da177e4 LT |
2246 | |
2247 | return retval; | |
2248 | } | |
2249 | ||
2250 | /** | |
11a96d18 | 2251 | * n_tty_write - write function for tty |
1da177e4 LT |
2252 | * @tty: tty device |
2253 | * @file: file object | |
2254 | * @buf: userspace buffer pointer | |
2255 | * @nr: size of I/O | |
2256 | * | |
a88a69c9 | 2257 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2258 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2259 | * and other such events. Since the receive code will echo characters, |
2260 | * thus calling driver write methods, the output_lock is used in | |
2261 | * the output processing functions called here as well as in the | |
2262 | * echo processing function to protect the column state and space | |
2263 | * left in the buffer. | |
1da177e4 LT |
2264 | * |
2265 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2266 | * |
2267 | * Locking: output_lock to protect column state and space left | |
2268 | * (note that the process_output*() functions take this | |
2269 | * lock themselves) | |
1da177e4 | 2270 | */ |
4edf1827 | 2271 | |
11a96d18 | 2272 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2273 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2274 | { |
2275 | const unsigned char *b = buf; | |
97d9e28d | 2276 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2277 | int c; |
2278 | ssize_t retval = 0; | |
2279 | ||
2280 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2281 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2282 | retval = tty_check_change(tty); | |
2283 | if (retval) | |
2284 | return retval; | |
2285 | } | |
2286 | ||
9356b535 PH |
2287 | down_read(&tty->termios_rwsem); |
2288 | ||
a88a69c9 JP |
2289 | /* Write out any echoed characters that are still pending */ |
2290 | process_echoes(tty); | |
300a6204 | 2291 | |
1da177e4 LT |
2292 | add_wait_queue(&tty->write_wait, &wait); |
2293 | while (1) { | |
1da177e4 LT |
2294 | if (signal_pending(current)) { |
2295 | retval = -ERESTARTSYS; | |
2296 | break; | |
2297 | } | |
2298 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2299 | retval = -EIO; | |
2300 | break; | |
2301 | } | |
582f5590 | 2302 | if (O_OPOST(tty)) { |
1da177e4 | 2303 | while (nr > 0) { |
a88a69c9 | 2304 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2305 | if (num < 0) { |
2306 | if (num == -EAGAIN) | |
2307 | break; | |
2308 | retval = num; | |
2309 | goto break_out; | |
2310 | } | |
2311 | b += num; | |
2312 | nr -= num; | |
2313 | if (nr == 0) | |
2314 | break; | |
2315 | c = *b; | |
a88a69c9 | 2316 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2317 | break; |
2318 | b++; nr--; | |
2319 | } | |
f34d7a5b AC |
2320 | if (tty->ops->flush_chars) |
2321 | tty->ops->flush_chars(tty); | |
1da177e4 | 2322 | } else { |
4291086b PH |
2323 | struct n_tty_data *ldata = tty->disc_data; |
2324 | ||
d6afe27b | 2325 | while (nr > 0) { |
4291086b | 2326 | mutex_lock(&ldata->output_lock); |
f34d7a5b | 2327 | c = tty->ops->write(tty, b, nr); |
4291086b | 2328 | mutex_unlock(&ldata->output_lock); |
d6afe27b RZ |
2329 | if (c < 0) { |
2330 | retval = c; | |
2331 | goto break_out; | |
2332 | } | |
2333 | if (!c) | |
2334 | break; | |
2335 | b += c; | |
2336 | nr -= c; | |
1da177e4 | 2337 | } |
1da177e4 LT |
2338 | } |
2339 | if (!nr) | |
2340 | break; | |
2341 | if (file->f_flags & O_NONBLOCK) { | |
2342 | retval = -EAGAIN; | |
2343 | break; | |
2344 | } | |
9356b535 PH |
2345 | up_read(&tty->termios_rwsem); |
2346 | ||
97d9e28d | 2347 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
9356b535 PH |
2348 | |
2349 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2350 | } |
2351 | break_out: | |
1da177e4 | 2352 | remove_wait_queue(&tty->write_wait, &wait); |
87108bc9 | 2353 | if (nr && tty->fasync) |
ff8cb0fd | 2354 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
9356b535 | 2355 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2356 | return (b - buf) ? b - buf : retval; |
2357 | } | |
2358 | ||
2359 | /** | |
11a96d18 | 2360 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2361 | * @tty: terminal device |
2362 | * @file: file accessing it | |
2363 | * @wait: poll table | |
2364 | * | |
2365 | * Called when the line discipline is asked to poll() for data or | |
2366 | * for special events. This code is not serialized with respect to | |
2367 | * other events save open/close. | |
2368 | * | |
2369 | * This code must be sure never to sleep through a hangup. | |
2370 | * Called without the kernel lock held - fine | |
1da177e4 | 2371 | */ |
4edf1827 | 2372 | |
11a96d18 | 2373 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2374 | poll_table *wait) |
1da177e4 LT |
2375 | { |
2376 | unsigned int mask = 0; | |
2377 | ||
2378 | poll_wait(file, &tty->read_wait, wait); | |
2379 | poll_wait(file, &tty->write_wait, wait); | |
eafbe67f | 2380 | if (input_available_p(tty, 1)) |
1da177e4 | 2381 | mask |= POLLIN | POLLRDNORM; |
0f40fbbc BB |
2382 | else { |
2383 | tty_buffer_flush_work(tty->port); | |
2384 | if (input_available_p(tty, 1)) | |
2385 | mask |= POLLIN | POLLRDNORM; | |
2386 | } | |
1da177e4 LT |
2387 | if (tty->packet && tty->link->ctrl_status) |
2388 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
0f40fbbc BB |
2389 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) |
2390 | mask |= POLLHUP; | |
1da177e4 LT |
2391 | if (tty_hung_up_p(file)) |
2392 | mask |= POLLHUP; | |
f34d7a5b AC |
2393 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2394 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2395 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2396 | mask |= POLLOUT | POLLWRNORM; |
2397 | return mask; | |
2398 | } | |
2399 | ||
57c94121 | 2400 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2401 | { |
bc5a5e3f | 2402 | size_t nr, head, tail; |
47afa7a5 | 2403 | |
a73d3d69 | 2404 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2405 | return 0; |
ba2e68ac JS |
2406 | head = ldata->canon_head; |
2407 | tail = ldata->read_tail; | |
bc5a5e3f | 2408 | nr = head - tail; |
47afa7a5 AC |
2409 | /* Skip EOF-chars.. */ |
2410 | while (head != tail) { | |
bc5a5e3f PH |
2411 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2412 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2413 | nr--; |
bc5a5e3f | 2414 | tail++; |
47afa7a5 AC |
2415 | } |
2416 | return nr; | |
2417 | } | |
2418 | ||
2419 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2420 | unsigned int cmd, unsigned long arg) | |
2421 | { | |
ba2e68ac | 2422 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2423 | int retval; |
2424 | ||
2425 | switch (cmd) { | |
2426 | case TIOCOUTQ: | |
2427 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2428 | case TIOCINQ: | |
6d76bd26 | 2429 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2430 | if (L_ICANON(tty)) |
57c94121 | 2431 | retval = inq_canon(ldata); |
6d76bd26 PH |
2432 | else |
2433 | retval = read_cnt(ldata); | |
2434 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2435 | return put_user(retval, (unsigned int __user *) arg); |
2436 | default: | |
2437 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2438 | } | |
2439 | } | |
2440 | ||
27228732 | 2441 | static struct tty_ldisc_ops n_tty_ops = { |
e10cc1df PF |
2442 | .magic = TTY_LDISC_MAGIC, |
2443 | .name = "n_tty", | |
2444 | .open = n_tty_open, | |
2445 | .close = n_tty_close, | |
2446 | .flush_buffer = n_tty_flush_buffer, | |
11a96d18 AC |
2447 | .read = n_tty_read, |
2448 | .write = n_tty_write, | |
e10cc1df PF |
2449 | .ioctl = n_tty_ioctl, |
2450 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2451 | .poll = n_tty_poll, |
e10cc1df | 2452 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 | 2453 | .write_wakeup = n_tty_write_wakeup, |
24a89d1c | 2454 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2455 | }; |
572b9adb RG |
2456 | |
2457 | /** | |
2458 | * n_tty_inherit_ops - inherit N_TTY methods | |
2459 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2460 | * | |
27228732 | 2461 | * Enables a 'subclass' line discipline to 'inherit' N_TTY methods. |
572b9adb RG |
2462 | */ |
2463 | ||
2464 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2465 | { | |
27228732 | 2466 | *ops = n_tty_ops; |
572b9adb RG |
2467 | ops->owner = NULL; |
2468 | ops->refcount = ops->flags = 0; | |
2469 | } | |
2470 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); | |
27228732 PH |
2471 | |
2472 | void __init n_tty_init(void) | |
2473 | { | |
2474 | tty_register_ldisc(N_TTY, &n_tty_ops); | |
2475 | } |