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; | |
93 | size_t canon_head; | |
9dfd16dd PH |
94 | size_t echo_head; |
95 | size_t echo_commit; | |
1bb9d562 | 96 | DECLARE_BITMAP(char_map, 256); |
fb7aa03d PH |
97 | |
98 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c JS |
99 | unsigned long overrun_time; |
100 | int num_overrun; | |
101 | ||
24a89d1c PH |
102 | /* non-atomic */ |
103 | bool no_room; | |
104 | ||
fb7aa03d | 105 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c | 106 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
3fe780b3 | 107 | |
fb7aa03d | 108 | /* shared by producer and consumer */ |
20bafb3d | 109 | char read_buf[N_TTY_BUF_SIZE]; |
3fe780b3 | 110 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
20bafb3d | 111 | unsigned char echo_buf[N_TTY_BUF_SIZE]; |
ba2e68ac | 112 | |
f6c8dbe6 | 113 | int minimum_to_wake; |
ba2e68ac | 114 | |
fb7aa03d PH |
115 | /* consumer-published */ |
116 | size_t read_tail; | |
40d5e090 | 117 | size_t line_start; |
fb7aa03d | 118 | |
fb7aa03d PH |
119 | /* protected by output lock */ |
120 | unsigned int column; | |
ba2e68ac | 121 | unsigned int canon_column; |
9dfd16dd | 122 | size_t echo_tail; |
bddc7152 JS |
123 | |
124 | struct mutex atomic_read_lock; | |
125 | struct mutex output_lock; | |
70ece7a7 JS |
126 | }; |
127 | ||
ce74117a PH |
128 | static inline size_t read_cnt(struct n_tty_data *ldata) |
129 | { | |
a2f73be8 | 130 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
131 | } |
132 | ||
bc5a5e3f PH |
133 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
134 | { | |
135 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
136 | } | |
137 | ||
138 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
139 | { | |
140 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
141 | } | |
142 | ||
addaebcc PH |
143 | static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) |
144 | { | |
145 | return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
146 | } | |
147 | ||
148 | static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) | |
149 | { | |
150 | return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
151 | } | |
152 | ||
522ed776 MT |
153 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
154 | unsigned char __user *ptr) | |
155 | { | |
53c5ee2c JS |
156 | struct n_tty_data *ldata = tty->disc_data; |
157 | ||
158 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
159 | return put_user(x, ptr); |
160 | } | |
161 | ||
24a89d1c | 162 | static int receive_room(struct tty_struct *tty) |
55db4c64 | 163 | { |
53c5ee2c | 164 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 165 | int left; |
55db4c64 | 166 | |
090abf7b JA |
167 | if (I_PARMRK(tty)) { |
168 | /* Multiply read_cnt by 3, since each byte might take up to | |
169 | * three times as many spaces when PARMRK is set (depending on | |
170 | * its flags, e.g. parity error). */ | |
ce74117a | 171 | left = N_TTY_BUF_SIZE - read_cnt(ldata) * 3 - 1; |
090abf7b | 172 | } else |
ce74117a | 173 | left = N_TTY_BUF_SIZE - read_cnt(ldata) - 1; |
090abf7b | 174 | |
55db4c64 LT |
175 | /* |
176 | * If we are doing input canonicalization, and there are no | |
177 | * pending newlines, let characters through without limit, so | |
178 | * that erase characters will be handled. Other excess | |
179 | * characters will be beeped. | |
180 | */ | |
181 | if (left <= 0) | |
a73d3d69 | 182 | left = ldata->icanon && ldata->canon_head == ldata->read_tail; |
55db4c64 | 183 | |
24a89d1c | 184 | return left; |
7879a9f9 PH |
185 | } |
186 | ||
24a89d1c PH |
187 | /** |
188 | * n_tty_set_room - receive space | |
189 | * @tty: terminal | |
190 | * | |
191 | * Re-schedules the flip buffer work if space just became available. | |
192 | * | |
6d76bd26 PH |
193 | * Caller holds exclusive termios_rwsem |
194 | * or | |
195 | * n_tty_read()/consumer path: | |
196 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
197 | */ |
198 | ||
7879a9f9 PH |
199 | static void n_tty_set_room(struct tty_struct *tty) |
200 | { | |
24a89d1c PH |
201 | struct n_tty_data *ldata = tty->disc_data; |
202 | ||
55db4c64 | 203 | /* Did this open up the receive buffer? We may need to flip */ |
24a89d1c PH |
204 | if (unlikely(ldata->no_room) && receive_room(tty)) { |
205 | ldata->no_room = 0; | |
206 | ||
ecbbfd44 | 207 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 208 | "scheduling with invalid itty\n"); |
21622939 PH |
209 | /* see if ldisc has been killed - if so, this means that |
210 | * even though the ldisc has been halted and ->buf.work | |
211 | * cancelled, ->buf.work is about to be rescheduled | |
212 | */ | |
213 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
214 | "scheduling buffer work for halted ldisc\n"); | |
f0f947c1 | 215 | queue_work(system_unbound_wq, &tty->port->buf.work); |
ecbbfd44 | 216 | } |
55db4c64 LT |
217 | } |
218 | ||
9a4aec2d PH |
219 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
220 | { | |
221 | struct n_tty_data *ldata = tty->disc_data; | |
222 | ssize_t n = 0; | |
223 | ||
224 | if (!ldata->icanon) | |
225 | n = read_cnt(ldata); | |
226 | else | |
227 | n = ldata->canon_head - ldata->read_tail; | |
228 | return n; | |
229 | } | |
230 | ||
ee0bab83 PH |
231 | /** |
232 | * n_tty_write_wakeup - asynchronous I/O notifier | |
233 | * @tty: tty device | |
234 | * | |
235 | * Required for the ptys, serial driver etc. since processes | |
236 | * that attach themselves to the master and rely on ASYNC | |
237 | * IO must be woken up | |
238 | */ | |
239 | ||
240 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
241 | { | |
242 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) | |
243 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
244 | } | |
245 | ||
4a23a4df | 246 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 247 | { |
3afb1b39 PH |
248 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) |
249 | return; | |
6367ca72 PH |
250 | /* |
251 | * Check the remaining room for the input canonicalization | |
252 | * mode. We don't want to throttle the driver if we're in | |
253 | * canonical mode and don't have a newline yet! | |
254 | */ | |
255 | while (1) { | |
256 | int throttled; | |
257 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
258 | if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) | |
259 | break; | |
260 | throttled = tty_throttle_safe(tty); | |
261 | if (!throttled) | |
262 | break; | |
263 | } | |
264 | __tty_set_flow_change(tty, 0); | |
265 | } | |
266 | ||
4b293492 | 267 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 268 | { |
3afb1b39 PH |
269 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
270 | tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { | |
271 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
272 | return; | |
273 | if (!tty->count) | |
274 | return; | |
275 | n_tty_set_room(tty); | |
276 | n_tty_write_wakeup(tty->link); | |
277 | wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); | |
278 | return; | |
279 | } | |
280 | ||
6367ca72 PH |
281 | /* If there is enough space in the read buffer now, let the |
282 | * low-level driver know. We use chars_in_buffer() to | |
283 | * check the buffer, as it now knows about canonical mode. | |
284 | * Otherwise, if the driver is throttled and the line is | |
285 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
286 | * we won't get any more characters. | |
287 | */ | |
288 | ||
289 | while (1) { | |
290 | int unthrottled; | |
291 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
292 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
293 | break; | |
294 | if (!tty->count) | |
295 | break; | |
296 | n_tty_set_room(tty); | |
297 | unthrottled = tty_unthrottle_safe(tty); | |
298 | if (!unthrottled) | |
299 | break; | |
300 | } | |
301 | __tty_set_flow_change(tty, 0); | |
302 | } | |
303 | ||
17b82060 AC |
304 | /** |
305 | * put_tty_queue - add character to tty | |
306 | * @c: character | |
57c94121 | 307 | * @ldata: n_tty data |
17b82060 | 308 | * |
6d76bd26 PH |
309 | * Add a character to the tty read_buf queue. |
310 | * | |
311 | * n_tty_receive_buf()/producer path: | |
312 | * caller holds non-exclusive termios_rwsem | |
313 | * modifies read_head | |
314 | * | |
315 | * read_head is only considered 'published' if canonical mode is | |
316 | * not active. | |
17b82060 AC |
317 | */ |
318 | ||
19e2ad6a | 319 | static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 320 | { |
19e2ad6a | 321 | *read_buf_addr(ldata, ldata->read_head++) = c; |
1da177e4 LT |
322 | } |
323 | ||
1da177e4 LT |
324 | /** |
325 | * reset_buffer_flags - reset buffer state | |
326 | * @tty: terminal to reset | |
327 | * | |
25518c68 PH |
328 | * Reset the read buffer counters and clear the flags. |
329 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 330 | * |
6d76bd26 PH |
331 | * Locking: caller holds exclusive termios_rwsem |
332 | * (or locking is not required) | |
1da177e4 | 333 | */ |
a88a69c9 | 334 | |
b66f4fa5 | 335 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 336 | { |
a73d3d69 | 337 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 338 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
40d5e090 | 339 | ldata->line_start = 0; |
a88a69c9 | 340 | |
a73d3d69 | 341 | ldata->erasing = 0; |
3fe780b3 | 342 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
1da177e4 LT |
343 | } |
344 | ||
a30737ab PH |
345 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
346 | { | |
347 | unsigned long flags; | |
348 | ||
349 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
350 | if (tty->link->packet) { | |
351 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
352 | wake_up_interruptible(&tty->link->read_wait); | |
353 | } | |
354 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
355 | } | |
356 | ||
1da177e4 LT |
357 | /** |
358 | * n_tty_flush_buffer - clean input queue | |
359 | * @tty: terminal device | |
360 | * | |
25518c68 PH |
361 | * Flush the input buffer. Called when the tty layer wants the |
362 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
363 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 364 | * |
6d76bd26 PH |
365 | * Holds termios_rwsem to exclude producer/consumer while |
366 | * buffer indices are reset. | |
367 | * | |
368 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 369 | */ |
4edf1827 AC |
370 | |
371 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 372 | { |
6d76bd26 | 373 | down_write(&tty->termios_rwsem); |
b66f4fa5 PH |
374 | reset_buffer_flags(tty->disc_data); |
375 | n_tty_set_room(tty); | |
4edf1827 | 376 | |
a30737ab PH |
377 | if (tty->link) |
378 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 379 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
380 | } |
381 | ||
6d76bd26 PH |
382 | /** |
383 | * n_tty_chars_in_buffer - report available bytes | |
384 | * @tty: tty device | |
385 | * | |
386 | * Report the number of characters buffered to be delivered to user | |
387 | * at this instant in time. | |
388 | * | |
389 | * Locking: exclusive termios_rwsem | |
390 | */ | |
391 | ||
a19d0c6a PH |
392 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
393 | { | |
6d76bd26 PH |
394 | ssize_t n; |
395 | ||
47534084 | 396 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
6d76bd26 PH |
397 | |
398 | down_write(&tty->termios_rwsem); | |
399 | n = chars_in_buffer(tty); | |
400 | up_write(&tty->termios_rwsem); | |
401 | return n; | |
a19d0c6a PH |
402 | } |
403 | ||
1da177e4 LT |
404 | /** |
405 | * is_utf8_continuation - utf8 multibyte check | |
406 | * @c: byte to check | |
407 | * | |
408 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
409 | * character. We use this to correctly compute the on screen size | |
410 | * of the character when printing | |
411 | */ | |
4edf1827 | 412 | |
1da177e4 LT |
413 | static inline int is_utf8_continuation(unsigned char c) |
414 | { | |
415 | return (c & 0xc0) == 0x80; | |
416 | } | |
417 | ||
418 | /** | |
419 | * is_continuation - multibyte check | |
420 | * @c: byte to check | |
421 | * | |
422 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
423 | * character and the terminal is in unicode mode. | |
424 | */ | |
4edf1827 | 425 | |
1da177e4 LT |
426 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
427 | { | |
428 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
429 | } | |
430 | ||
431 | /** | |
a88a69c9 | 432 | * do_output_char - output one character |
1da177e4 LT |
433 | * @c: character (or partial unicode symbol) |
434 | * @tty: terminal device | |
a88a69c9 | 435 | * @space: space available in tty driver write buffer |
1da177e4 | 436 | * |
a88a69c9 JP |
437 | * This is a helper function that handles one output character |
438 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
439 | * doing OPOST processing and putting the results in the |
440 | * tty driver's write buffer. | |
a88a69c9 JP |
441 | * |
442 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
443 | * and NLDLY. They simply aren't relevant in the world today. | |
444 | * If you ever need them, add them here. | |
1da177e4 | 445 | * |
a88a69c9 JP |
446 | * Returns the number of bytes of buffer space used or -1 if |
447 | * no space left. | |
448 | * | |
449 | * Locking: should be called under the output_lock to protect | |
450 | * the column state and space left in the buffer | |
1da177e4 | 451 | */ |
4edf1827 | 452 | |
a88a69c9 | 453 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 454 | { |
53c5ee2c | 455 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 456 | int spaces; |
1da177e4 | 457 | |
1da177e4 LT |
458 | if (!space) |
459 | return -1; | |
300a6204 | 460 | |
a88a69c9 JP |
461 | switch (c) { |
462 | case '\n': | |
463 | if (O_ONLRET(tty)) | |
53c5ee2c | 464 | ldata->column = 0; |
a88a69c9 JP |
465 | if (O_ONLCR(tty)) { |
466 | if (space < 2) | |
467 | return -1; | |
ba2e68ac | 468 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 469 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
470 | return 2; |
471 | } | |
ba2e68ac | 472 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
473 | break; |
474 | case '\r': | |
53c5ee2c | 475 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
476 | return 0; |
477 | if (O_OCRNL(tty)) { | |
478 | c = '\n'; | |
479 | if (O_ONLRET(tty)) | |
ba2e68ac | 480 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 481 | break; |
a88a69c9 | 482 | } |
ba2e68ac | 483 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
484 | break; |
485 | case '\t': | |
53c5ee2c | 486 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
487 | if (O_TABDLY(tty) == XTABS) { |
488 | if (space < spaces) | |
489 | return -1; | |
53c5ee2c | 490 | ldata->column += spaces; |
a88a69c9 JP |
491 | tty->ops->write(tty, " ", spaces); |
492 | return spaces; | |
1da177e4 | 493 | } |
53c5ee2c | 494 | ldata->column += spaces; |
a88a69c9 JP |
495 | break; |
496 | case '\b': | |
53c5ee2c JS |
497 | if (ldata->column > 0) |
498 | ldata->column--; | |
a88a69c9 JP |
499 | break; |
500 | default: | |
a59c0d6f JP |
501 | if (!iscntrl(c)) { |
502 | if (O_OLCUC(tty)) | |
503 | c = toupper(c); | |
504 | if (!is_continuation(c, tty)) | |
53c5ee2c | 505 | ldata->column++; |
a59c0d6f | 506 | } |
a88a69c9 | 507 | break; |
1da177e4 | 508 | } |
a88a69c9 | 509 | |
f34d7a5b | 510 | tty_put_char(tty, c); |
a88a69c9 JP |
511 | return 1; |
512 | } | |
513 | ||
514 | /** | |
515 | * process_output - output post processor | |
516 | * @c: character (or partial unicode symbol) | |
517 | * @tty: terminal device | |
518 | * | |
ee5aa7b8 JP |
519 | * Output one character with OPOST processing. |
520 | * Returns -1 when the output device is full and the character | |
521 | * must be retried. | |
a88a69c9 JP |
522 | * |
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) | |
526 | */ | |
527 | ||
528 | static int process_output(unsigned char c, struct tty_struct *tty) | |
529 | { | |
bddc7152 | 530 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
531 | int space, retval; |
532 | ||
bddc7152 | 533 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
534 | |
535 | space = tty_write_room(tty); | |
536 | retval = do_output_char(c, tty, space); | |
537 | ||
bddc7152 | 538 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
539 | if (retval < 0) |
540 | return -1; | |
541 | else | |
542 | return 0; | |
1da177e4 LT |
543 | } |
544 | ||
545 | /** | |
a88a69c9 | 546 | * process_output_block - block post processor |
1da177e4 | 547 | * @tty: terminal device |
ee5aa7b8 JP |
548 | * @buf: character buffer |
549 | * @nr: number of bytes to output | |
550 | * | |
551 | * Output a block of characters with OPOST processing. | |
552 | * Returns the number of characters output. | |
1da177e4 LT |
553 | * |
554 | * This path is used to speed up block console writes, among other | |
555 | * things when processing blocks of output data. It handles only | |
556 | * the simple cases normally found and helps to generate blocks of | |
557 | * symbols for the console driver and thus improve performance. | |
558 | * | |
a88a69c9 JP |
559 | * Locking: output_lock to protect column state and space left |
560 | * (also, this is called from n_tty_write under the | |
561 | * tty layer write lock) | |
1da177e4 | 562 | */ |
4edf1827 | 563 | |
a88a69c9 JP |
564 | static ssize_t process_output_block(struct tty_struct *tty, |
565 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 566 | { |
53c5ee2c | 567 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 568 | int space; |
bbd20759 | 569 | int i; |
1da177e4 LT |
570 | const unsigned char *cp; |
571 | ||
bddc7152 | 572 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 573 | |
f34d7a5b | 574 | space = tty_write_room(tty); |
300a6204 | 575 | if (!space) { |
bddc7152 | 576 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 577 | return 0; |
a88a69c9 | 578 | } |
1da177e4 LT |
579 | if (nr > space) |
580 | nr = space; | |
581 | ||
582 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
583 | unsigned char c = *cp; |
584 | ||
585 | switch (c) { | |
1da177e4 LT |
586 | case '\n': |
587 | if (O_ONLRET(tty)) | |
53c5ee2c | 588 | ldata->column = 0; |
1da177e4 LT |
589 | if (O_ONLCR(tty)) |
590 | goto break_out; | |
ba2e68ac | 591 | ldata->canon_column = ldata->column; |
1da177e4 LT |
592 | break; |
593 | case '\r': | |
53c5ee2c | 594 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
595 | goto break_out; |
596 | if (O_OCRNL(tty)) | |
597 | goto break_out; | |
ba2e68ac | 598 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
599 | break; |
600 | case '\t': | |
601 | goto break_out; | |
602 | case '\b': | |
53c5ee2c JS |
603 | if (ldata->column > 0) |
604 | ldata->column--; | |
1da177e4 LT |
605 | break; |
606 | default: | |
a59c0d6f JP |
607 | if (!iscntrl(c)) { |
608 | if (O_OLCUC(tty)) | |
609 | goto break_out; | |
610 | if (!is_continuation(c, tty)) | |
53c5ee2c | 611 | ldata->column++; |
a59c0d6f | 612 | } |
1da177e4 LT |
613 | break; |
614 | } | |
615 | } | |
616 | break_out: | |
f34d7a5b | 617 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 618 | |
bddc7152 | 619 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
620 | return i; |
621 | } | |
622 | ||
a88a69c9 JP |
623 | /** |
624 | * process_echoes - write pending echo characters | |
625 | * @tty: terminal device | |
626 | * | |
627 | * Write previously buffered echo (and other ldisc-generated) | |
628 | * characters to the tty. | |
629 | * | |
630 | * Characters generated by the ldisc (including echoes) need to | |
631 | * be buffered because the driver's write buffer can fill during | |
632 | * heavy program output. Echoing straight to the driver will | |
633 | * often fail under these conditions, causing lost characters and | |
634 | * resulting mismatches of ldisc state information. | |
635 | * | |
636 | * Since the ldisc state must represent the characters actually sent | |
637 | * to the driver at the time of the write, operations like certain | |
638 | * changes in column state are also saved in the buffer and executed | |
639 | * here. | |
640 | * | |
641 | * A circular fifo buffer is used so that the most recent characters | |
642 | * are prioritized. Also, when control characters are echoed with a | |
643 | * prefixed "^", the pair is treated atomically and thus not separated. | |
644 | * | |
019ebdf9 | 645 | * Locking: callers must hold output_lock |
a88a69c9 JP |
646 | */ |
647 | ||
bc5b1ec5 | 648 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 649 | { |
53c5ee2c | 650 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 651 | int space, old_space; |
addaebcc | 652 | size_t tail; |
a88a69c9 | 653 | unsigned char c; |
a88a69c9 | 654 | |
bc5b1ec5 | 655 | old_space = space = tty_write_room(tty); |
a88a69c9 | 656 | |
addaebcc | 657 | tail = ldata->echo_tail; |
29c7c5ca | 658 | while (ldata->echo_commit != tail) { |
addaebcc | 659 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
660 | if (c == ECHO_OP_START) { |
661 | unsigned char op; | |
a88a69c9 JP |
662 | int no_space_left = 0; |
663 | ||
664 | /* | |
665 | * If the buffer byte is the start of a multi-byte | |
666 | * operation, get the next byte, which is either the | |
667 | * op code or a control character value. | |
668 | */ | |
addaebcc | 669 | op = echo_buf(ldata, tail + 1); |
300a6204 | 670 | |
a88a69c9 JP |
671 | switch (op) { |
672 | unsigned int num_chars, num_bs; | |
673 | ||
674 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 675 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
676 | |
677 | /* | |
678 | * Determine how many columns to go back | |
679 | * in order to erase the tab. | |
680 | * This depends on the number of columns | |
681 | * used by other characters within the tab | |
682 | * area. If this (modulo 8) count is from | |
683 | * the start of input rather than from a | |
684 | * previous tab, we offset by canon column. | |
685 | * Otherwise, tab spacing is normal. | |
686 | */ | |
687 | if (!(num_chars & 0x80)) | |
ba2e68ac | 688 | num_chars += ldata->canon_column; |
a88a69c9 JP |
689 | num_bs = 8 - (num_chars & 7); |
690 | ||
691 | if (num_bs > space) { | |
692 | no_space_left = 1; | |
693 | break; | |
694 | } | |
695 | space -= num_bs; | |
696 | while (num_bs--) { | |
697 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
698 | if (ldata->column > 0) |
699 | ldata->column--; | |
a88a69c9 | 700 | } |
addaebcc | 701 | tail += 3; |
a88a69c9 JP |
702 | break; |
703 | ||
704 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 705 | ldata->canon_column = ldata->column; |
addaebcc | 706 | tail += 2; |
a88a69c9 JP |
707 | break; |
708 | ||
709 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
710 | if (ldata->column > 0) |
711 | ldata->column--; | |
addaebcc | 712 | tail += 2; |
a88a69c9 JP |
713 | break; |
714 | ||
715 | case ECHO_OP_START: | |
716 | /* This is an escaped echo op start code */ | |
717 | if (!space) { | |
718 | no_space_left = 1; | |
719 | break; | |
720 | } | |
721 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 722 | ldata->column++; |
a88a69c9 | 723 | space--; |
addaebcc | 724 | tail += 2; |
a88a69c9 JP |
725 | break; |
726 | ||
727 | default: | |
a88a69c9 | 728 | /* |
62b26358 JP |
729 | * If the op is not a special byte code, |
730 | * it is a ctrl char tagged to be echoed | |
731 | * as "^X" (where X is the letter | |
732 | * representing the control char). | |
733 | * Note that we must ensure there is | |
734 | * enough space for the whole ctrl pair. | |
735 | * | |
a88a69c9 | 736 | */ |
62b26358 JP |
737 | if (space < 2) { |
738 | no_space_left = 1; | |
739 | break; | |
740 | } | |
741 | tty_put_char(tty, '^'); | |
742 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 743 | ldata->column += 2; |
62b26358 | 744 | space -= 2; |
addaebcc | 745 | tail += 2; |
a88a69c9 JP |
746 | } |
747 | ||
748 | if (no_space_left) | |
749 | break; | |
750 | } else { | |
582f5590 | 751 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
752 | int retval = do_output_char(c, tty, space); |
753 | if (retval < 0) | |
754 | break; | |
755 | space -= retval; | |
756 | } else { | |
757 | if (!space) | |
758 | break; | |
759 | tty_put_char(tty, c); | |
760 | space -= 1; | |
761 | } | |
addaebcc | 762 | tail += 1; |
a88a69c9 | 763 | } |
a88a69c9 JP |
764 | } |
765 | ||
cbfd0340 PH |
766 | /* If the echo buffer is nearly full (so that the possibility exists |
767 | * of echo overrun before the next commit), then discard enough | |
768 | * data at the tail to prevent a subsequent overrun */ | |
769 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 770 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 771 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
772 | tail += 3; |
773 | else | |
774 | tail += 2; | |
775 | } else | |
776 | tail++; | |
777 | } | |
778 | ||
addaebcc | 779 | ldata->echo_tail = tail; |
bc5b1ec5 | 780 | return old_space - space; |
019ebdf9 PH |
781 | } |
782 | ||
783 | static void commit_echoes(struct tty_struct *tty) | |
784 | { | |
785 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 786 | size_t nr, old, echoed; |
cbfd0340 PH |
787 | size_t head; |
788 | ||
789 | head = ldata->echo_head; | |
790 | old = ldata->echo_commit - ldata->echo_tail; | |
791 | ||
792 | /* Process committed echoes if the accumulated # of bytes | |
793 | * is over the threshold (and try again each time another | |
794 | * block is accumulated) */ | |
795 | nr = head - ldata->echo_tail; | |
796 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
797 | return; | |
a88a69c9 | 798 | |
019ebdf9 | 799 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 800 | ldata->echo_commit = head; |
bc5b1ec5 | 801 | echoed = __process_echoes(tty); |
bddc7152 | 802 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 803 | |
bc5b1ec5 | 804 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
805 | tty->ops->flush_chars(tty); |
806 | } | |
807 | ||
019ebdf9 | 808 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
809 | { |
810 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 811 | size_t echoed; |
17bd7907 | 812 | |
39434abd PH |
813 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
814 | ldata->echo_commit == ldata->echo_tail) | |
019ebdf9 PH |
815 | return; |
816 | ||
817 | mutex_lock(&ldata->output_lock); | |
bc5b1ec5 | 818 | echoed = __process_echoes(tty); |
019ebdf9 PH |
819 | mutex_unlock(&ldata->output_lock); |
820 | ||
bc5b1ec5 | 821 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 822 | tty->ops->flush_chars(tty); |
17bd7907 PH |
823 | } |
824 | ||
cbfd0340 PH |
825 | static void flush_echoes(struct tty_struct *tty) |
826 | { | |
827 | struct n_tty_data *ldata = tty->disc_data; | |
828 | ||
39434abd PH |
829 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
830 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
831 | return; |
832 | ||
833 | mutex_lock(&ldata->output_lock); | |
834 | ldata->echo_commit = ldata->echo_head; | |
835 | __process_echoes(tty); | |
836 | mutex_unlock(&ldata->output_lock); | |
837 | } | |
838 | ||
a88a69c9 JP |
839 | /** |
840 | * add_echo_byte - add a byte to the echo buffer | |
841 | * @c: unicode byte to echo | |
57c94121 | 842 | * @ldata: n_tty data |
a88a69c9 JP |
843 | * |
844 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
845 | */ |
846 | ||
cbfd0340 | 847 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 848 | { |
addaebcc | 849 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
850 | } |
851 | ||
852 | /** | |
853 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 854 | * @ldata: n_tty data |
a88a69c9 JP |
855 | * |
856 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
857 | */ |
858 | ||
57c94121 | 859 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 860 | { |
57c94121 JS |
861 | add_echo_byte(ECHO_OP_START, ldata); |
862 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
863 | } |
864 | ||
865 | /** | |
866 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 867 | * @ldata: n_tty data |
a88a69c9 JP |
868 | * |
869 | * Add an operation to the echo buffer to set the canon column | |
870 | * to the current column. | |
a88a69c9 JP |
871 | */ |
872 | ||
57c94121 | 873 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 874 | { |
57c94121 JS |
875 | add_echo_byte(ECHO_OP_START, ldata); |
876 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
877 | } |
878 | ||
879 | /** | |
880 | * echo_erase_tab - add operation to erase a tab | |
881 | * @num_chars: number of character columns already used | |
882 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 883 | * @ldata: n_tty data |
a88a69c9 JP |
884 | * |
885 | * Add an operation to the echo buffer to erase a tab. | |
886 | * | |
887 | * Called by the eraser function, which knows how many character | |
888 | * columns have been used since either a previous tab or the start | |
889 | * of input. This information will be used later, along with | |
890 | * canon column (if applicable), to go back the correct number | |
891 | * of columns. | |
a88a69c9 JP |
892 | */ |
893 | ||
894 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 895 | struct n_tty_data *ldata) |
a88a69c9 | 896 | { |
57c94121 JS |
897 | add_echo_byte(ECHO_OP_START, ldata); |
898 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
899 | |
900 | /* We only need to know this modulo 8 (tab spacing) */ | |
901 | num_chars &= 7; | |
902 | ||
903 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
904 | if (after_tab) | |
905 | num_chars |= 0x80; | |
300a6204 | 906 | |
57c94121 | 907 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
908 | } |
909 | ||
910 | /** | |
911 | * echo_char_raw - echo a character raw | |
912 | * @c: unicode byte to echo | |
913 | * @tty: terminal device | |
914 | * | |
915 | * Echo user input back onto the screen. This must be called only when | |
916 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
917 | * | |
918 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
919 | */ |
920 | ||
57c94121 | 921 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 922 | { |
a88a69c9 | 923 | if (c == ECHO_OP_START) { |
57c94121 JS |
924 | add_echo_byte(ECHO_OP_START, ldata); |
925 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 926 | } else { |
57c94121 | 927 | add_echo_byte(c, ldata); |
a88a69c9 | 928 | } |
a88a69c9 | 929 | } |
1da177e4 | 930 | |
1da177e4 | 931 | /** |
a88a69c9 | 932 | * echo_char - echo a character |
1da177e4 LT |
933 | * @c: unicode byte to echo |
934 | * @tty: terminal device | |
935 | * | |
4edf1827 | 936 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 937 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 938 | * |
62b26358 JP |
939 | * This variant tags control characters to be echoed as "^X" |
940 | * (where X is the letter representing the control char). | |
1da177e4 LT |
941 | */ |
942 | ||
943 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
944 | { | |
bddc7152 JS |
945 | struct n_tty_data *ldata = tty->disc_data; |
946 | ||
a88a69c9 | 947 | if (c == ECHO_OP_START) { |
57c94121 JS |
948 | add_echo_byte(ECHO_OP_START, ldata); |
949 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 950 | } else { |
62b26358 | 951 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
952 | add_echo_byte(ECHO_OP_START, ldata); |
953 | add_echo_byte(c, ldata); | |
a88a69c9 | 954 | } |
1da177e4 LT |
955 | } |
956 | ||
17b82060 | 957 | /** |
a88a69c9 | 958 | * finish_erasing - complete erase |
57c94121 | 959 | * @ldata: n_tty data |
17b82060 | 960 | */ |
a88a69c9 | 961 | |
57c94121 | 962 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 963 | { |
53c5ee2c | 964 | if (ldata->erasing) { |
57c94121 | 965 | echo_char_raw('/', ldata); |
53c5ee2c | 966 | ldata->erasing = 0; |
1da177e4 LT |
967 | } |
968 | } | |
969 | ||
970 | /** | |
971 | * eraser - handle erase function | |
972 | * @c: character input | |
973 | * @tty: terminal device | |
974 | * | |
3a4fa0a2 | 975 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
976 | * present in the stream from the driver layer. Handles the complexities |
977 | * of UTF-8 multibyte symbols. | |
17b82060 | 978 | * |
6d76bd26 PH |
979 | * n_tty_receive_buf()/producer path: |
980 | * caller holds non-exclusive termios_rwsem | |
981 | * modifies read_head | |
982 | * | |
983 | * Modifying the read_head is not considered a publish in this context | |
984 | * because canonical mode is active -- only canon_head publishes | |
1da177e4 | 985 | */ |
4edf1827 | 986 | |
1da177e4 LT |
987 | static void eraser(unsigned char c, struct tty_struct *tty) |
988 | { | |
53c5ee2c | 989 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 990 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
991 | size_t head; |
992 | size_t cnt; | |
993 | int seen_alnums; | |
1da177e4 | 994 | |
ba2e68ac | 995 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 996 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
997 | return; |
998 | } | |
999 | if (c == ERASE_CHAR(tty)) | |
1000 | kill_type = ERASE; | |
1001 | else if (c == WERASE_CHAR(tty)) | |
1002 | kill_type = WERASE; | |
1003 | else { | |
1004 | if (!L_ECHO(tty)) { | |
ba2e68ac | 1005 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
1006 | return; |
1007 | } | |
1008 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 1009 | ldata->read_head = ldata->canon_head; |
57c94121 | 1010 | finish_erasing(ldata); |
1da177e4 LT |
1011 | echo_char(KILL_CHAR(tty), tty); |
1012 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
1013 | if (L_ECHOK(tty)) | |
57c94121 | 1014 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1015 | return; |
1016 | } | |
1017 | kill_type = KILL; | |
1018 | } | |
1019 | ||
1020 | seen_alnums = 0; | |
ba2e68ac JS |
1021 | while (ldata->read_head != ldata->canon_head) { |
1022 | head = ldata->read_head; | |
1da177e4 LT |
1023 | |
1024 | /* erase a single possibly multibyte character */ | |
1025 | do { | |
bc5a5e3f PH |
1026 | head--; |
1027 | c = read_buf(ldata, head); | |
ba2e68ac | 1028 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1029 | |
1030 | /* do not partially erase */ | |
1031 | if (is_continuation(c, tty)) | |
1032 | break; | |
1033 | ||
1034 | if (kill_type == WERASE) { | |
1035 | /* Equivalent to BSD's ALTWERASE. */ | |
1036 | if (isalnum(c) || c == '_') | |
1037 | seen_alnums++; | |
1038 | else if (seen_alnums) | |
1039 | break; | |
1040 | } | |
bc5a5e3f | 1041 | cnt = ldata->read_head - head; |
ba2e68ac | 1042 | ldata->read_head = head; |
1da177e4 LT |
1043 | if (L_ECHO(tty)) { |
1044 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1045 | if (!ldata->erasing) { |
57c94121 | 1046 | echo_char_raw('\\', ldata); |
53c5ee2c | 1047 | ldata->erasing = 1; |
1da177e4 LT |
1048 | } |
1049 | /* if cnt > 1, output a multi-byte character */ | |
1050 | echo_char(c, tty); | |
1051 | while (--cnt > 0) { | |
bc5a5e3f PH |
1052 | head++; |
1053 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1054 | echo_move_back_col(ldata); |
1da177e4 LT |
1055 | } |
1056 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1057 | echo_char(ERASE_CHAR(tty), tty); | |
1058 | } else if (c == '\t') { | |
a88a69c9 JP |
1059 | unsigned int num_chars = 0; |
1060 | int after_tab = 0; | |
bc5a5e3f | 1061 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1062 | |
1063 | /* | |
1064 | * Count the columns used for characters | |
1065 | * since the start of input or after a | |
1066 | * previous tab. | |
1067 | * This info is used to go back the correct | |
1068 | * number of columns. | |
1069 | */ | |
ba2e68ac | 1070 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1071 | tail--; |
1072 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1073 | if (c == '\t') { |
1074 | after_tab = 1; | |
1075 | break; | |
300a6204 | 1076 | } else if (iscntrl(c)) { |
1da177e4 | 1077 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1078 | num_chars += 2; |
1079 | } else if (!is_continuation(c, tty)) { | |
1080 | num_chars++; | |
1081 | } | |
1da177e4 | 1082 | } |
57c94121 | 1083 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1084 | } else { |
1085 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1086 | echo_char_raw('\b', ldata); |
1087 | echo_char_raw(' ', ldata); | |
1088 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1089 | } |
1090 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1091 | echo_char_raw('\b', ldata); |
1092 | echo_char_raw(' ', ldata); | |
1093 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1094 | } |
1095 | } | |
1096 | } | |
1097 | if (kill_type == ERASE) | |
1098 | break; | |
1099 | } | |
ba2e68ac | 1100 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1101 | finish_erasing(ldata); |
1da177e4 LT |
1102 | } |
1103 | ||
1104 | /** | |
1105 | * isig - handle the ISIG optio | |
1106 | * @sig: signal | |
1107 | * @tty: terminal | |
1da177e4 | 1108 | * |
8c985d18 PH |
1109 | * Called when a signal is being sent due to terminal input. |
1110 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1111 | * |
8c985d18 | 1112 | * Locking: ctrl_lock |
1da177e4 | 1113 | */ |
4edf1827 | 1114 | |
4b293492 | 1115 | static void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1116 | { |
8c985d18 PH |
1117 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1118 | if (tty_pgrp) { | |
1119 | kill_pgrp(tty_pgrp, sig, 1); | |
1120 | put_pid(tty_pgrp); | |
1da177e4 LT |
1121 | } |
1122 | } | |
1123 | ||
1124 | /** | |
1125 | * n_tty_receive_break - handle break | |
1126 | * @tty: terminal | |
1127 | * | |
1128 | * An RS232 break event has been hit in the incoming bitstream. This | |
1129 | * can cause a variety of events depending upon the termios settings. | |
1130 | * | |
6d76bd26 PH |
1131 | * n_tty_receive_buf()/producer path: |
1132 | * caller holds non-exclusive termios_rwsem | |
1133 | * publishes read_head via put_tty_queue() | |
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 PH |
1145 | isig(SIGINT, tty); |
1146 | if (!L_NOFLSH(tty)) { | |
6d76bd26 PH |
1147 | /* flushing needs exclusive termios_rwsem */ |
1148 | up_read(&tty->termios_rwsem); | |
8c985d18 PH |
1149 | n_tty_flush_buffer(tty); |
1150 | tty_driver_flush_buffer(tty); | |
6d76bd26 | 1151 | down_read(&tty->termios_rwsem); |
8c985d18 | 1152 | } |
1da177e4 LT |
1153 | return; |
1154 | } | |
1155 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1156 | put_tty_queue('\377', ldata); |
1157 | put_tty_queue('\0', ldata); | |
1da177e4 | 1158 | } |
57c94121 | 1159 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1160 | wake_up_interruptible(&tty->read_wait); |
1161 | } | |
1162 | ||
1163 | /** | |
1164 | * n_tty_receive_overrun - handle overrun reporting | |
1165 | * @tty: terminal | |
1166 | * | |
1167 | * Data arrived faster than we could process it. While the tty | |
1168 | * driver has flagged this the bits that were missed are gone | |
1169 | * forever. | |
1170 | * | |
1171 | * Called from the receive_buf path so single threaded. Does not | |
1172 | * need locking as num_overrun and overrun_time are function | |
1173 | * private. | |
1174 | */ | |
4edf1827 | 1175 | |
4b293492 | 1176 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1177 | { |
53c5ee2c | 1178 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1179 | char buf[64]; |
1180 | ||
53c5ee2c JS |
1181 | ldata->num_overrun++; |
1182 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1183 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1184 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1185 | tty_name(tty, buf), | |
53c5ee2c JS |
1186 | ldata->num_overrun); |
1187 | ldata->overrun_time = jiffies; | |
1188 | ldata->num_overrun = 0; | |
1da177e4 LT |
1189 | } |
1190 | } | |
1191 | ||
1192 | /** | |
1193 | * n_tty_receive_parity_error - error notifier | |
1194 | * @tty: terminal device | |
1195 | * @c: character | |
1196 | * | |
1197 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1198 | * the error case if necessary. |
1199 | * | |
1200 | * n_tty_receive_buf()/producer path: | |
1201 | * caller holds non-exclusive termios_rwsem | |
1202 | * publishes read_head via put_tty_queue() | |
1da177e4 | 1203 | */ |
4b293492 | 1204 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1205 | { |
57c94121 JS |
1206 | struct n_tty_data *ldata = tty->disc_data; |
1207 | ||
4edf1827 | 1208 | if (I_IGNPAR(tty)) |
1da177e4 | 1209 | return; |
1da177e4 | 1210 | if (I_PARMRK(tty)) { |
57c94121 JS |
1211 | put_tty_queue('\377', ldata); |
1212 | put_tty_queue('\0', ldata); | |
1213 | put_tty_queue(c, ldata); | |
1da177e4 | 1214 | } else if (I_INPCK(tty)) |
57c94121 | 1215 | put_tty_queue('\0', ldata); |
1da177e4 | 1216 | else |
57c94121 | 1217 | put_tty_queue(c, ldata); |
1da177e4 LT |
1218 | wake_up_interruptible(&tty->read_wait); |
1219 | } | |
1220 | ||
b0ac50be PH |
1221 | static void |
1222 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1223 | { | |
1224 | if (!L_NOFLSH(tty)) { | |
1225 | /* flushing needs exclusive termios_rwsem */ | |
1226 | up_read(&tty->termios_rwsem); | |
1227 | n_tty_flush_buffer(tty); | |
1228 | tty_driver_flush_buffer(tty); | |
1229 | down_read(&tty->termios_rwsem); | |
1230 | } | |
1231 | if (I_IXON(tty)) | |
1232 | start_tty(tty); | |
1233 | if (L_ECHO(tty)) { | |
1234 | echo_char(c, tty); | |
1235 | commit_echoes(tty); | |
1236 | } | |
1237 | isig(signal, tty); | |
1238 | return; | |
1239 | } | |
1240 | ||
1da177e4 LT |
1241 | /** |
1242 | * n_tty_receive_char - perform processing | |
1243 | * @tty: terminal device | |
1244 | * @c: character | |
1245 | * | |
1246 | * Process an individual character of input received from the driver. | |
4edf1827 | 1247 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1248 | * driver above. |
6d76bd26 PH |
1249 | * |
1250 | * n_tty_receive_buf()/producer path: | |
1251 | * caller holds non-exclusive termios_rwsem | |
1252 | * publishes canon_head if canonical mode is active | |
1253 | * otherwise, publishes read_head via put_tty_queue() | |
e60d27c4 PH |
1254 | * |
1255 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1256 | */ |
1257 | ||
e60d27c4 | 1258 | static int |
4b1f79c2 | 1259 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1260 | { |
53c5ee2c | 1261 | struct n_tty_data *ldata = tty->disc_data; |
acc71bba | 1262 | int parmrk; |
1da177e4 | 1263 | |
1da177e4 LT |
1264 | if (I_IXON(tty)) { |
1265 | if (c == START_CHAR(tty)) { | |
1266 | start_tty(tty); | |
17bd7907 | 1267 | commit_echoes(tty); |
e60d27c4 | 1268 | return 0; |
1da177e4 LT |
1269 | } |
1270 | if (c == STOP_CHAR(tty)) { | |
1271 | stop_tty(tty); | |
e60d27c4 | 1272 | return 0; |
1da177e4 LT |
1273 | } |
1274 | } | |
575537b3 | 1275 | |
1da177e4 | 1276 | if (L_ISIG(tty)) { |
b0ac50be PH |
1277 | if (c == INTR_CHAR(tty)) { |
1278 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1279 | return 0; |
b0ac50be PH |
1280 | } else if (c == QUIT_CHAR(tty)) { |
1281 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1282 | return 0; |
b0ac50be PH |
1283 | } else if (c == SUSP_CHAR(tty)) { |
1284 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1285 | return 0; |
1da177e4 LT |
1286 | } |
1287 | } | |
575537b3 | 1288 | |
855df3c0 PH |
1289 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1290 | start_tty(tty); | |
1291 | process_echoes(tty); | |
1292 | } | |
1293 | ||
575537b3 JP |
1294 | if (c == '\r') { |
1295 | if (I_IGNCR(tty)) | |
e60d27c4 | 1296 | return 0; |
575537b3 JP |
1297 | if (I_ICRNL(tty)) |
1298 | c = '\n'; | |
1299 | } else if (c == '\n' && I_INLCR(tty)) | |
1300 | c = '\r'; | |
1301 | ||
53c5ee2c | 1302 | if (ldata->icanon) { |
1da177e4 LT |
1303 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1304 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1305 | eraser(c, tty); | |
17bd7907 | 1306 | commit_echoes(tty); |
e60d27c4 | 1307 | return 0; |
1da177e4 LT |
1308 | } |
1309 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1310 | ldata->lnext = 1; |
1da177e4 | 1311 | if (L_ECHO(tty)) { |
57c94121 | 1312 | finish_erasing(ldata); |
1da177e4 | 1313 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1314 | echo_char_raw('^', ldata); |
1315 | echo_char_raw('\b', ldata); | |
17bd7907 | 1316 | commit_echoes(tty); |
1da177e4 LT |
1317 | } |
1318 | } | |
e60d27c4 | 1319 | return 1; |
1da177e4 | 1320 | } |
e60d27c4 | 1321 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1322 | size_t tail = ldata->canon_head; |
1da177e4 | 1323 | |
57c94121 | 1324 | finish_erasing(ldata); |
1da177e4 | 1325 | echo_char(c, tty); |
57c94121 | 1326 | echo_char_raw('\n', ldata); |
ba2e68ac | 1327 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1328 | echo_char(read_buf(ldata, tail), tty); |
1329 | tail++; | |
1da177e4 | 1330 | } |
17bd7907 | 1331 | commit_echoes(tty); |
e60d27c4 | 1332 | return 0; |
1da177e4 LT |
1333 | } |
1334 | if (c == '\n') { | |
acc71bba | 1335 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1336 | echo_char_raw('\n', ldata); |
17bd7907 | 1337 | commit_echoes(tty); |
1da177e4 LT |
1338 | } |
1339 | goto handle_newline; | |
1340 | } | |
1341 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1342 | c = __DISABLED_CHAR; |
1343 | goto handle_newline; | |
1344 | } | |
1345 | if ((c == EOL_CHAR(tty)) || | |
1346 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1347 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1348 | ? 1 : 0; | |
1da177e4 LT |
1349 | /* |
1350 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1351 | */ | |
1352 | if (L_ECHO(tty)) { | |
1da177e4 | 1353 | /* Record the column of first canon char. */ |
ba2e68ac | 1354 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1355 | echo_set_canon_col(ldata); |
1da177e4 | 1356 | echo_char(c, tty); |
17bd7907 | 1357 | commit_echoes(tty); |
1da177e4 LT |
1358 | } |
1359 | /* | |
1360 | * XXX does PARMRK doubling happen for | |
1361 | * EOL_CHAR and EOL2_CHAR? | |
1362 | */ | |
acc71bba | 1363 | if (parmrk) |
57c94121 | 1364 | put_tty_queue(c, ldata); |
1da177e4 | 1365 | |
4edf1827 | 1366 | handle_newline: |
bc5a5e3f | 1367 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1368 | put_tty_queue(c, ldata); |
ba2e68ac | 1369 | ldata->canon_head = ldata->read_head; |
1da177e4 LT |
1370 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1371 | if (waitqueue_active(&tty->read_wait)) | |
1372 | wake_up_interruptible(&tty->read_wait); | |
e60d27c4 | 1373 | return 0; |
1da177e4 LT |
1374 | } |
1375 | } | |
4edf1827 | 1376 | |
acc71bba | 1377 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
acc71bba | 1378 | if (L_ECHO(tty)) { |
57c94121 | 1379 | finish_erasing(ldata); |
1da177e4 | 1380 | if (c == '\n') |
57c94121 | 1381 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1382 | else { |
1383 | /* Record the column of first canon char. */ | |
ba2e68ac | 1384 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1385 | echo_set_canon_col(ldata); |
1da177e4 LT |
1386 | echo_char(c, tty); |
1387 | } | |
17bd7907 | 1388 | commit_echoes(tty); |
1da177e4 LT |
1389 | } |
1390 | ||
acc71bba | 1391 | if (parmrk) |
57c94121 | 1392 | put_tty_queue(c, ldata); |
1da177e4 | 1393 | |
57c94121 | 1394 | put_tty_queue(c, ldata); |
e60d27c4 | 1395 | return 0; |
4edf1827 | 1396 | } |
1da177e4 | 1397 | |
e60d27c4 PH |
1398 | static inline void |
1399 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1400 | { |
1401 | struct n_tty_data *ldata = tty->disc_data; | |
1402 | int parmrk; | |
1403 | ||
e60d27c4 PH |
1404 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1405 | start_tty(tty); | |
1406 | process_echoes(tty); | |
1407 | } | |
1408 | if (L_ECHO(tty)) { | |
1409 | finish_erasing(ldata); | |
1410 | /* Record the column of first canon char. */ | |
1411 | if (ldata->canon_head == ldata->read_head) | |
1412 | echo_set_canon_col(ldata); | |
1413 | echo_char(c, tty); | |
1414 | commit_echoes(tty); | |
4b1f79c2 | 1415 | } |
e60d27c4 PH |
1416 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
1417 | if (parmrk) | |
1418 | put_tty_queue(c, ldata); | |
1419 | put_tty_queue(c, ldata); | |
1420 | } | |
4b1f79c2 | 1421 | |
e60d27c4 PH |
1422 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
1423 | { | |
1424 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1425 | } |
1426 | ||
7de971b0 PH |
1427 | static inline void |
1428 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1429 | { | |
1430 | struct n_tty_data *ldata = tty->disc_data; | |
1431 | ||
e60d27c4 PH |
1432 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1433 | start_tty(tty); | |
1434 | process_echoes(tty); | |
7de971b0 | 1435 | } |
e60d27c4 PH |
1436 | if (L_ECHO(tty)) { |
1437 | finish_erasing(ldata); | |
1438 | /* Record the column of first canon char. */ | |
1439 | if (ldata->canon_head == ldata->read_head) | |
1440 | echo_set_canon_col(ldata); | |
1441 | echo_char(c, tty); | |
1442 | commit_echoes(tty); | |
1443 | } | |
1444 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1445 | } |
1446 | ||
ad0cc7ba PH |
1447 | static inline void |
1448 | n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) | |
1449 | { | |
1450 | if (I_ISTRIP(tty)) | |
1451 | c &= 0x7f; | |
1452 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1453 | c = tolower(c); | |
1454 | ||
1455 | if (I_IXON(tty)) { | |
1456 | if (c == STOP_CHAR(tty)) | |
1457 | stop_tty(tty); | |
1458 | else if (c == START_CHAR(tty) || | |
1459 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1460 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1461 | c != SUSP_CHAR(tty))) { | |
1462 | start_tty(tty); | |
1463 | process_echoes(tty); | |
1464 | } | |
1465 | } | |
1466 | } | |
1467 | ||
d2f8d7ab PH |
1468 | static void |
1469 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1470 | { | |
1471 | char buf[64]; | |
1472 | ||
1473 | switch (flag) { | |
1474 | case TTY_BREAK: | |
1475 | n_tty_receive_break(tty); | |
1476 | break; | |
1477 | case TTY_PARITY: | |
1478 | case TTY_FRAME: | |
1479 | n_tty_receive_parity_error(tty, c); | |
1480 | break; | |
1481 | case TTY_OVERRUN: | |
1482 | n_tty_receive_overrun(tty); | |
1483 | break; | |
1484 | default: | |
1485 | printk(KERN_ERR "%s: unknown flag %d\n", | |
1486 | tty_name(tty, buf), flag); | |
1487 | break; | |
1488 | } | |
1489 | } | |
1490 | ||
e60d27c4 PH |
1491 | static void |
1492 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1493 | { | |
1494 | struct n_tty_data *ldata = tty->disc_data; | |
1495 | ||
1496 | ldata->lnext = 0; | |
1497 | if (likely(flag == TTY_NORMAL)) { | |
1498 | if (I_ISTRIP(tty)) | |
1499 | c &= 0x7f; | |
1500 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1501 | c = tolower(c); | |
1502 | n_tty_receive_char(tty, c); | |
1503 | } else | |
1504 | n_tty_receive_char_flagged(tty, c, flag); | |
1505 | } | |
1506 | ||
1da177e4 LT |
1507 | /** |
1508 | * n_tty_receive_buf - data receive | |
1509 | * @tty: terminal device | |
1510 | * @cp: buffer | |
1511 | * @fp: flag buffer | |
1512 | * @count: characters | |
1513 | * | |
1514 | * Called by the terminal driver when a block of characters has | |
1515 | * been received. This function must be called from soft contexts | |
1516 | * not from interrupt context. The driver is responsible for making | |
1517 | * calls one at a time and in order (or using flush_to_ldisc) | |
6d76bd26 PH |
1518 | * |
1519 | * n_tty_receive_buf()/producer path: | |
1520 | * claims non-exclusive termios_rwsem | |
1521 | * publishes read_head and canon_head | |
1da177e4 | 1522 | */ |
4edf1827 | 1523 | |
4a23a4df PH |
1524 | static void |
1525 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1526 | char *fp, int count) | |
1527 | { | |
1528 | struct n_tty_data *ldata = tty->disc_data; | |
1529 | size_t n, head; | |
1530 | ||
1531 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1532 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1533 | n = min_t(size_t, count, n); | |
1534 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1535 | ldata->read_head += n; | |
1536 | cp += n; | |
1537 | count -= n; | |
1538 | ||
1539 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1540 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1541 | n = min_t(size_t, count, n); | |
1542 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1543 | ldata->read_head += n; | |
1544 | } | |
1545 | ||
554117bd PH |
1546 | static void |
1547 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1548 | char *fp, int count) | |
1549 | { | |
1550 | struct n_tty_data *ldata = tty->disc_data; | |
1551 | char flag = TTY_NORMAL; | |
1552 | ||
1553 | while (count--) { | |
1554 | if (fp) | |
1555 | flag = *fp++; | |
1556 | if (likely(flag == TTY_NORMAL)) | |
1557 | put_tty_queue(*cp++, ldata); | |
1558 | else | |
1559 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1560 | } | |
1561 | } | |
1562 | ||
ad0cc7ba PH |
1563 | static void |
1564 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1565 | char *fp, int count) | |
1566 | { | |
1567 | char flag = TTY_NORMAL; | |
1568 | ||
1569 | while (count--) { | |
1570 | if (fp) | |
1571 | flag = *fp++; | |
1572 | if (likely(flag == TTY_NORMAL)) | |
1573 | n_tty_receive_char_closing(tty, *cp++); | |
1574 | else | |
1575 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1576 | } | |
1577 | } | |
1578 | ||
7d88d637 PH |
1579 | static void |
1580 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1581 | char *fp, int count) |
1582 | { | |
1583 | struct n_tty_data *ldata = tty->disc_data; | |
1584 | char flag = TTY_NORMAL; | |
1585 | ||
1586 | while (count--) { | |
1587 | if (fp) | |
1588 | flag = *fp++; | |
1589 | if (likely(flag == TTY_NORMAL)) { | |
1590 | unsigned char c = *cp++; | |
1591 | ||
1592 | if (I_ISTRIP(tty)) | |
1593 | c &= 0x7f; | |
1594 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1595 | c = tolower(c); | |
1596 | if (L_EXTPROC(tty)) { | |
1597 | put_tty_queue(c, ldata); | |
1598 | continue; | |
1599 | } | |
e60d27c4 PH |
1600 | if (!test_bit(c, ldata->char_map)) |
1601 | n_tty_receive_char_inline(tty, c); | |
1602 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1603 | if (fp) | |
1604 | flag = *fp++; | |
1605 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1606 | count--; | |
1607 | } | |
6baad008 PH |
1608 | } else |
1609 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1610 | } | |
1611 | } | |
1612 | ||
1613 | static void | |
1614 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1615 | char *fp, int count) | |
7d88d637 | 1616 | { |
e60d27c4 | 1617 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1618 | char flag = TTY_NORMAL; |
1619 | ||
1620 | while (count--) { | |
1621 | if (fp) | |
1622 | flag = *fp++; | |
e60d27c4 PH |
1623 | if (likely(flag == TTY_NORMAL)) { |
1624 | unsigned char c = *cp++; | |
1625 | ||
1626 | if (!test_bit(c, ldata->char_map)) | |
1627 | n_tty_receive_char_fast(tty, c); | |
1628 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1629 | if (fp) | |
1630 | flag = *fp++; | |
1631 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1632 | count--; | |
1633 | } | |
1634 | } else | |
7d88d637 PH |
1635 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1636 | } | |
1637 | } | |
1638 | ||
24a89d1c PH |
1639 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1640 | char *fp, int count) | |
1da177e4 | 1641 | { |
53c5ee2c | 1642 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1643 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1644 | |
4a23a4df PH |
1645 | if (ldata->real_raw) |
1646 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1647 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1648 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1649 | else if (tty->closing && !L_EXTPROC(tty)) |
1650 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1651 | else { |
e60d27c4 PH |
1652 | if (ldata->lnext) { |
1653 | char flag = TTY_NORMAL; | |
1654 | ||
1655 | if (fp) | |
1656 | flag = *fp++; | |
1657 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1658 | count--; | |
1659 | } | |
1660 | ||
7de971b0 | 1661 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1662 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1663 | else | |
1664 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1665 | |
1666 | flush_echoes(tty); | |
f34d7a5b AC |
1667 | if (tty->ops->flush_chars) |
1668 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1669 | } |
1670 | ||
ce74117a | 1671 | if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) || |
26df6d13 | 1672 | L_EXTPROC(tty)) { |
1da177e4 LT |
1673 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1674 | if (waitqueue_active(&tty->read_wait)) | |
1675 | wake_up_interruptible(&tty->read_wait); | |
1676 | } | |
1da177e4 LT |
1677 | } |
1678 | ||
24a89d1c PH |
1679 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1680 | char *fp, int count) | |
1681 | { | |
19e2ad6a PH |
1682 | int room, n; |
1683 | ||
9356b535 | 1684 | down_read(&tty->termios_rwsem); |
19e2ad6a PH |
1685 | |
1686 | while (1) { | |
1687 | room = receive_room(tty); | |
1688 | n = min(count, room); | |
1689 | if (!n) | |
1690 | break; | |
1691 | __receive_buf(tty, cp, fp, n); | |
1692 | cp += n; | |
1693 | if (fp) | |
1694 | fp += n; | |
1695 | count -= n; | |
1696 | } | |
1697 | ||
1698 | tty->receive_room = room; | |
4a23a4df | 1699 | n_tty_check_throttle(tty); |
9356b535 | 1700 | up_read(&tty->termios_rwsem); |
24a89d1c PH |
1701 | } |
1702 | ||
1703 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1704 | char *fp, int count) | |
1705 | { | |
1706 | struct n_tty_data *ldata = tty->disc_data; | |
19e2ad6a | 1707 | int room, n, rcvd = 0; |
24a89d1c | 1708 | |
9356b535 PH |
1709 | down_read(&tty->termios_rwsem); |
1710 | ||
19e2ad6a PH |
1711 | while (1) { |
1712 | room = receive_room(tty); | |
1713 | n = min(count, room); | |
1714 | if (!n) { | |
1715 | if (!room) | |
1716 | ldata->no_room = 1; | |
1717 | break; | |
1718 | } | |
1719 | __receive_buf(tty, cp, fp, n); | |
1720 | cp += n; | |
1721 | if (fp) | |
1722 | fp += n; | |
1723 | count -= n; | |
1724 | rcvd += n; | |
4a23a4df | 1725 | } |
24a89d1c | 1726 | |
19e2ad6a PH |
1727 | tty->receive_room = room; |
1728 | n_tty_check_throttle(tty); | |
9356b535 PH |
1729 | up_read(&tty->termios_rwsem); |
1730 | ||
19e2ad6a | 1731 | return rcvd; |
24a89d1c PH |
1732 | } |
1733 | ||
1da177e4 LT |
1734 | int is_ignored(int sig) |
1735 | { | |
1736 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1737 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1738 | } |
1739 | ||
1740 | /** | |
1741 | * n_tty_set_termios - termios data changed | |
1742 | * @tty: terminal | |
1743 | * @old: previous data | |
1744 | * | |
1745 | * Called by the tty layer when the user changes termios flags so | |
1746 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1747 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1748 | * guaranteed that this function will not be re-entered or in progress |
1749 | * when the ldisc is closed. | |
17b82060 | 1750 | * |
6a1c0680 | 1751 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1752 | */ |
4edf1827 AC |
1753 | |
1754 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1755 | { |
53c5ee2c | 1756 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1757 | |
c786f74e | 1758 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { |
3fe780b3 | 1759 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
93a8d416 | 1760 | ldata->line_start = ldata->canon_head = ldata->read_tail; |
53c5ee2c | 1761 | ldata->erasing = 0; |
6f9b028a | 1762 | ldata->lnext = 0; |
47afa7a5 AC |
1763 | } |
1764 | ||
53c5ee2c | 1765 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1766 | |
1da177e4 LT |
1767 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1768 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1769 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1770 | I_PARMRK(tty)) { | |
1bb9d562 | 1771 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1772 | |
1773 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1774 | set_bit('\r', ldata->char_map); |
1da177e4 | 1775 | if (I_INLCR(tty)) |
1bb9d562 | 1776 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1777 | |
1778 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1779 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1780 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1781 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1782 | set_bit('\n', ldata->char_map); | |
1783 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1784 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1785 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1786 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1787 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1788 | if (L_ECHO(tty)) |
1789 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1790 | ldata->char_map); |
1da177e4 LT |
1791 | } |
1792 | } | |
1793 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1794 | set_bit(START_CHAR(tty), ldata->char_map); |
1795 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1796 | } |
1797 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1798 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1799 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1800 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1801 | } |
1bb9d562 | 1802 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1803 | ldata->raw = 0; |
1804 | ldata->real_raw = 0; | |
1da177e4 | 1805 | } else { |
53c5ee2c | 1806 | ldata->raw = 1; |
1da177e4 LT |
1807 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1808 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1809 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1810 | ldata->real_raw = 1; |
1da177e4 | 1811 | else |
53c5ee2c | 1812 | ldata->real_raw = 0; |
1da177e4 | 1813 | } |
55db4c64 | 1814 | n_tty_set_room(tty); |
dab73b4e WY |
1815 | /* |
1816 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1817 | * been stopped by STOP_CHAR(tty) before it. | |
1818 | */ | |
103fcbe2 | 1819 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) |
dab73b4e | 1820 | start_tty(tty); |
dab73b4e | 1821 | |
f34d7a5b AC |
1822 | /* The termios change make the tty ready for I/O */ |
1823 | wake_up_interruptible(&tty->write_wait); | |
1824 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1825 | } |
1826 | ||
1827 | /** | |
1828 | * n_tty_close - close the ldisc for this tty | |
1829 | * @tty: device | |
1830 | * | |
4edf1827 AC |
1831 | * Called from the terminal layer when this line discipline is |
1832 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1833 | * discipline change. The function will not be called while other |
1834 | * ldisc methods are in progress. | |
1835 | */ | |
4edf1827 | 1836 | |
1da177e4 LT |
1837 | static void n_tty_close(struct tty_struct *tty) |
1838 | { | |
70ece7a7 JS |
1839 | struct n_tty_data *ldata = tty->disc_data; |
1840 | ||
79901317 PH |
1841 | if (tty->link) |
1842 | n_tty_packet_mode_flush(tty); | |
1843 | ||
20bafb3d | 1844 | vfree(ldata); |
70ece7a7 | 1845 | tty->disc_data = NULL; |
1da177e4 LT |
1846 | } |
1847 | ||
1848 | /** | |
1849 | * n_tty_open - open an ldisc | |
1850 | * @tty: terminal to open | |
1851 | * | |
4edf1827 | 1852 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1853 | * terminal device. Can sleep. Called serialized so that no |
1854 | * other events will occur in parallel. No further open will occur | |
1855 | * until a close. | |
1856 | */ | |
1857 | ||
1858 | static int n_tty_open(struct tty_struct *tty) | |
1859 | { | |
70ece7a7 JS |
1860 | struct n_tty_data *ldata; |
1861 | ||
20bafb3d PH |
1862 | /* Currently a malloc failure here can panic */ |
1863 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1864 | if (!ldata) |
1865 | goto err; | |
1866 | ||
53c5ee2c | 1867 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1868 | mutex_init(&ldata->atomic_read_lock); |
1869 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1870 | |
70ece7a7 | 1871 | tty->disc_data = ldata; |
b66f4fa5 | 1872 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1873 | ldata->column = 0; |
20bafb3d | 1874 | ldata->canon_column = 0; |
f6c8dbe6 | 1875 | ldata->minimum_to_wake = 1; |
20bafb3d PH |
1876 | ldata->num_overrun = 0; |
1877 | ldata->no_room = 0; | |
1878 | ldata->lnext = 0; | |
1da177e4 | 1879 | tty->closing = 0; |
b66f4fa5 PH |
1880 | /* indicate buffer work may resume */ |
1881 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1882 | n_tty_set_termios(tty, NULL); | |
1883 | tty_unthrottle(tty); | |
70ece7a7 | 1884 | |
1da177e4 | 1885 | return 0; |
70ece7a7 | 1886 | err: |
b91939f5 | 1887 | return -ENOMEM; |
1da177e4 LT |
1888 | } |
1889 | ||
1890 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1891 | { | |
53c5ee2c JS |
1892 | struct n_tty_data *ldata = tty->disc_data; |
1893 | ||
53c5ee2c | 1894 | if (ldata->icanon && !L_EXTPROC(tty)) { |
a73d3d69 | 1895 | if (ldata->canon_head != ldata->read_tail) |
1da177e4 | 1896 | return 1; |
ce74117a | 1897 | } else if (read_cnt(ldata) >= (amt ? amt : 1)) |
1da177e4 LT |
1898 | return 1; |
1899 | ||
1900 | return 0; | |
1901 | } | |
1902 | ||
1903 | /** | |
bbd20759 | 1904 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1905 | * @tty: terminal device |
1906 | * @b: user data | |
1907 | * @nr: size of data | |
1908 | * | |
11a96d18 | 1909 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1910 | * ICANON is off; it copies characters straight from the tty queue to |
1911 | * user space directly. It can be profitably called twice; once to | |
1912 | * drain the space from the tail pointer to the (physical) end of the | |
1913 | * buffer, and once to drain the space from the (physical) beginning of | |
1914 | * the buffer to head pointer. | |
1915 | * | |
bddc7152 | 1916 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1917 | * |
6d76bd26 PH |
1918 | * n_tty_read()/consumer path: |
1919 | * caller holds non-exclusive termios_rwsem | |
1920 | * read_tail published | |
1da177e4 | 1921 | */ |
4edf1827 | 1922 | |
33f0f88f | 1923 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1924 | unsigned char __user **b, |
1925 | size_t *nr) | |
1926 | ||
1927 | { | |
53c5ee2c | 1928 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1929 | int retval; |
1930 | size_t n; | |
3fa10cc8 | 1931 | bool is_eof; |
bc5a5e3f | 1932 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1933 | |
1934 | retval = 0; | |
bc5a5e3f | 1935 | n = min(read_cnt(ldata), N_TTY_BUF_SIZE - tail); |
1da177e4 | 1936 | n = min(*nr, n); |
1da177e4 | 1937 | if (n) { |
bc5a5e3f | 1938 | retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
1da177e4 | 1939 | n -= retval; |
bc5a5e3f PH |
1940 | is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); |
1941 | tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, | |
53c5ee2c | 1942 | ldata->icanon); |
bc5a5e3f | 1943 | ldata->read_tail += n; |
26df6d13 | 1944 | /* Turn single EOF into zero-length read */ |
ce74117a | 1945 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !read_cnt(ldata)) |
3fa10cc8 | 1946 | n = 0; |
1da177e4 LT |
1947 | *b += n; |
1948 | *nr -= n; | |
1949 | } | |
1950 | return retval; | |
1951 | } | |
1952 | ||
88bb0de3 | 1953 | /** |
32f13521 | 1954 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1955 | * @tty: terminal device |
1956 | * @b: user data | |
1957 | * @nr: size of data | |
1958 | * | |
1959 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1960 | * it copies one line of input up to and including the line-delimiting |
1961 | * character into the user-space buffer. | |
88bb0de3 PH |
1962 | * |
1963 | * Called under the atomic_read_lock mutex | |
6d76bd26 PH |
1964 | * |
1965 | * n_tty_read()/consumer path: | |
1966 | * caller holds non-exclusive termios_rwsem | |
1967 | * read_tail published | |
88bb0de3 PH |
1968 | */ |
1969 | ||
32f13521 PH |
1970 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
1971 | unsigned char __user **b, | |
1972 | size_t *nr) | |
88bb0de3 PH |
1973 | { |
1974 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 1975 | size_t n, size, more, c; |
bc5a5e3f PH |
1976 | size_t eol; |
1977 | size_t tail; | |
1978 | int ret, found = 0; | |
40d5e090 | 1979 | bool eof_push = 0; |
88bb0de3 PH |
1980 | |
1981 | /* N.B. avoid overrun if nr == 0 */ | |
ce74117a | 1982 | n = min(*nr, read_cnt(ldata)); |
6d76bd26 | 1983 | if (!n) |
32f13521 | 1984 | return 0; |
88bb0de3 | 1985 | |
bc5a5e3f | 1986 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
1987 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
1988 | ||
bc5a5e3f | 1989 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
1990 | __func__, *nr, tail, n, size); |
1991 | ||
1992 | eol = find_next_bit(ldata->read_flags, size, tail); | |
1993 | more = n - (size - tail); | |
1994 | if (eol == N_TTY_BUF_SIZE && more) { | |
1995 | /* scan wrapped without finding set bit */ | |
1996 | eol = find_next_bit(ldata->read_flags, more, 0); | |
1997 | if (eol != more) | |
1998 | found = 1; | |
1999 | } else if (eol != size) | |
2000 | found = 1; | |
2001 | ||
2002 | size = N_TTY_BUF_SIZE - tail; | |
c77569d2 PH |
2003 | n = eol - tail; |
2004 | if (n > 4096) | |
2005 | n += 4096; | |
2006 | n += found; | |
32f13521 PH |
2007 | c = n; |
2008 | ||
40d5e090 | 2009 | if (found && read_buf(ldata, eol) == __DISABLED_CHAR) { |
32f13521 | 2010 | n--; |
40d5e090 PH |
2011 | eof_push = !n && ldata->read_tail != ldata->line_start; |
2012 | } | |
32f13521 | 2013 | |
bc5a5e3f | 2014 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", |
32f13521 PH |
2015 | __func__, eol, found, n, c, size, more); |
2016 | ||
32f13521 | 2017 | if (n > size) { |
bc5a5e3f | 2018 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), size); |
32f13521 PH |
2019 | if (ret) |
2020 | return -EFAULT; | |
2021 | ret = copy_to_user(*b + size, ldata->read_buf, n - size); | |
2022 | } else | |
bc5a5e3f | 2023 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
32f13521 PH |
2024 | |
2025 | if (ret) | |
2026 | return -EFAULT; | |
2027 | *b += n; | |
2028 | *nr -= n; | |
2029 | ||
a73d3d69 | 2030 | if (found) |
6d76bd26 PH |
2031 | clear_bit(eol, ldata->read_flags); |
2032 | smp_mb__after_clear_bit(); | |
2033 | ldata->read_tail += c; | |
88bb0de3 | 2034 | |
40d5e090 PH |
2035 | if (found) { |
2036 | ldata->line_start = ldata->read_tail; | |
32f13521 | 2037 | tty_audit_push(tty); |
40d5e090 PH |
2038 | } |
2039 | return eof_push ? -EAGAIN : 0; | |
88bb0de3 PH |
2040 | } |
2041 | ||
cc4191dc | 2042 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2043 | size_t, loff_t *); |
1da177e4 LT |
2044 | |
2045 | /** | |
2046 | * job_control - check job control | |
2047 | * @tty: tty | |
2048 | * @file: file handle | |
2049 | * | |
2050 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2051 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2052 | * error code if action should be taken. |
04f378b1 | 2053 | * |
01a5e440 PH |
2054 | * Locking: redirected write test is safe |
2055 | * current->signal->tty check is safe | |
2056 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2057 | */ |
4edf1827 | 2058 | |
1da177e4 LT |
2059 | static int job_control(struct tty_struct *tty, struct file *file) |
2060 | { | |
2061 | /* Job control check -- must be done at start and after | |
2062 | every sleep (POSIX.1 7.1.1.4). */ | |
2063 | /* NOTE: not yet done after every sleep pending a thorough | |
2064 | check of the logic of this change. -- jlc */ | |
2065 | /* don't stop on /dev/console */ | |
01a5e440 PH |
2066 | if (file->f_op->write == redirected_tty_write || |
2067 | current->signal->tty != tty) | |
2068 | return 0; | |
2069 | ||
2070 | spin_lock_irq(&tty->ctrl_lock); | |
2071 | if (!tty->pgrp) | |
2072 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
2073 | else if (task_pgrp(current) != tty->pgrp) { | |
2074 | spin_unlock_irq(&tty->ctrl_lock); | |
2075 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
2076 | return -EIO; | |
2077 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
2078 | set_thread_flag(TIF_SIGPENDING); | |
2079 | return -ERESTARTSYS; | |
1da177e4 | 2080 | } |
01a5e440 | 2081 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
2082 | return 0; |
2083 | } | |
4edf1827 | 2084 | |
1da177e4 LT |
2085 | |
2086 | /** | |
11a96d18 | 2087 | * n_tty_read - read function for tty |
1da177e4 LT |
2088 | * @tty: tty device |
2089 | * @file: file object | |
2090 | * @buf: userspace buffer pointer | |
2091 | * @nr: size of I/O | |
2092 | * | |
2093 | * Perform reads for the line discipline. We are guaranteed that the | |
2094 | * line discipline will not be closed under us but we may get multiple | |
2095 | * parallel readers and must handle this ourselves. We may also get | |
2096 | * a hangup. Always called in user context, may sleep. | |
2097 | * | |
2098 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2099 | * |
2100 | * n_tty_read()/consumer path: | |
2101 | * claims non-exclusive termios_rwsem | |
2102 | * publishes read_tail | |
1da177e4 | 2103 | */ |
4edf1827 | 2104 | |
11a96d18 | 2105 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2106 | unsigned char __user *buf, size_t nr) |
2107 | { | |
53c5ee2c | 2108 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2109 | unsigned char __user *b = buf; |
2110 | DECLARE_WAITQUEUE(wait, current); | |
2111 | int c; | |
2112 | int minimum, time; | |
2113 | ssize_t retval = 0; | |
1da177e4 LT |
2114 | long timeout; |
2115 | unsigned long flags; | |
04f378b1 | 2116 | int packet; |
1da177e4 | 2117 | |
1da177e4 | 2118 | c = job_control(tty, file); |
4edf1827 | 2119 | if (c < 0) |
1da177e4 | 2120 | return c; |
4edf1827 | 2121 | |
aefceaf4 PH |
2122 | /* |
2123 | * Internal serialization of reads. | |
2124 | */ | |
2125 | if (file->f_flags & O_NONBLOCK) { | |
2126 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2127 | return -EAGAIN; | |
2128 | } else { | |
2129 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2130 | return -ERESTARTSYS; | |
2131 | } | |
2132 | ||
9356b535 PH |
2133 | down_read(&tty->termios_rwsem); |
2134 | ||
1da177e4 LT |
2135 | minimum = time = 0; |
2136 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2137 | if (!ldata->icanon) { |
1da177e4 LT |
2138 | minimum = MIN_CHAR(tty); |
2139 | if (minimum) { | |
a6e54319 | 2140 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2141 | if (time) |
f6c8dbe6 | 2142 | ldata->minimum_to_wake = 1; |
1da177e4 | 2143 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
2144 | (ldata->minimum_to_wake > minimum)) |
2145 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 2146 | } else { |
a6e54319 | 2147 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2148 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2149 | } |
2150 | } | |
2151 | ||
04f378b1 | 2152 | packet = tty->packet; |
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; | |
04f378b1 | 2161 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
2162 | cs = tty->link->ctrl_status; |
2163 | tty->link->ctrl_status = 0; | |
04f378b1 | 2164 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 2165 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2166 | retval = -EFAULT; |
2167 | b--; | |
2168 | break; | |
2169 | } | |
2170 | nr--; | |
2171 | break; | |
2172 | } | |
2173 | /* This statement must be first before checking for input | |
2174 | so that any interrupt will set the state back to | |
2175 | TASK_RUNNING. */ | |
2176 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 2177 | |
f6c8dbe6 | 2178 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2179 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2180 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2181 | |
1da177e4 LT |
2182 | if (!input_available_p(tty, 0)) { |
2183 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
f8747d4a PH |
2184 | up_read(&tty->termios_rwsem); |
2185 | tty_flush_to_ldisc(tty); | |
2186 | down_read(&tty->termios_rwsem); | |
2187 | if (!input_available_p(tty, 0)) { | |
2188 | retval = -EIO; | |
2189 | break; | |
2190 | } | |
2191 | } else { | |
2192 | if (tty_hung_up_p(file)) | |
2193 | break; | |
2194 | if (!timeout) | |
2195 | break; | |
2196 | if (file->f_flags & O_NONBLOCK) { | |
2197 | retval = -EAGAIN; | |
2198 | break; | |
2199 | } | |
2200 | if (signal_pending(current)) { | |
2201 | retval = -ERESTARTSYS; | |
2202 | break; | |
2203 | } | |
2204 | n_tty_set_room(tty); | |
2205 | up_read(&tty->termios_rwsem); | |
9356b535 | 2206 | |
f8747d4a | 2207 | timeout = schedule_timeout(timeout); |
9356b535 | 2208 | |
f8747d4a PH |
2209 | down_read(&tty->termios_rwsem); |
2210 | continue; | |
2211 | } | |
1da177e4 LT |
2212 | } |
2213 | __set_current_state(TASK_RUNNING); | |
2214 | ||
2215 | /* Deal with packet mode. */ | |
04f378b1 | 2216 | if (packet && b == buf) { |
522ed776 | 2217 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
2218 | retval = -EFAULT; |
2219 | b--; | |
2220 | break; | |
2221 | } | |
2222 | nr--; | |
2223 | } | |
2224 | ||
53c5ee2c | 2225 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2226 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
40d5e090 PH |
2227 | if (retval == -EAGAIN) { |
2228 | retval = 0; | |
2229 | continue; | |
2230 | } else if (retval) | |
1da177e4 LT |
2231 | break; |
2232 | } else { | |
2233 | int uncopied; | |
04f378b1 AC |
2234 | /* The copy function takes the read lock and handles |
2235 | locking internally for this case */ | |
1da177e4 LT |
2236 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2237 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2238 | if (uncopied) { | |
2239 | retval = -EFAULT; | |
2240 | break; | |
2241 | } | |
2242 | } | |
2243 | ||
6367ca72 | 2244 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2245 | |
2246 | if (b - buf >= minimum) | |
2247 | break; | |
2248 | if (time) | |
2249 | timeout = time; | |
2250 | } | |
42458f41 PH |
2251 | n_tty_set_room(tty); |
2252 | up_read(&tty->termios_rwsem); | |
2253 | ||
1da177e4 | 2254 | remove_wait_queue(&tty->read_wait, &wait); |
1da177e4 | 2255 | if (!waitqueue_active(&tty->read_wait)) |
f6c8dbe6 | 2256 | ldata->minimum_to_wake = minimum; |
1da177e4 | 2257 | |
aebf0453 PH |
2258 | mutex_unlock(&ldata->atomic_read_lock); |
2259 | ||
1da177e4 | 2260 | __set_current_state(TASK_RUNNING); |
40d5e090 PH |
2261 | if (b - buf) |
2262 | retval = b - buf; | |
1da177e4 LT |
2263 | |
2264 | return retval; | |
2265 | } | |
2266 | ||
2267 | /** | |
11a96d18 | 2268 | * n_tty_write - write function for tty |
1da177e4 LT |
2269 | * @tty: tty device |
2270 | * @file: file object | |
2271 | * @buf: userspace buffer pointer | |
2272 | * @nr: size of I/O | |
2273 | * | |
a88a69c9 | 2274 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2275 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2276 | * and other such events. Since the receive code will echo characters, |
2277 | * thus calling driver write methods, the output_lock is used in | |
2278 | * the output processing functions called here as well as in the | |
2279 | * echo processing function to protect the column state and space | |
2280 | * left in the buffer. | |
1da177e4 LT |
2281 | * |
2282 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2283 | * |
2284 | * Locking: output_lock to protect column state and space left | |
2285 | * (note that the process_output*() functions take this | |
2286 | * lock themselves) | |
1da177e4 | 2287 | */ |
4edf1827 | 2288 | |
11a96d18 | 2289 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2290 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2291 | { |
2292 | const unsigned char *b = buf; | |
2293 | DECLARE_WAITQUEUE(wait, current); | |
2294 | int c; | |
2295 | ssize_t retval = 0; | |
2296 | ||
2297 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2298 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2299 | retval = tty_check_change(tty); | |
2300 | if (retval) | |
2301 | return retval; | |
2302 | } | |
2303 | ||
9356b535 PH |
2304 | down_read(&tty->termios_rwsem); |
2305 | ||
a88a69c9 JP |
2306 | /* Write out any echoed characters that are still pending */ |
2307 | process_echoes(tty); | |
300a6204 | 2308 | |
1da177e4 LT |
2309 | add_wait_queue(&tty->write_wait, &wait); |
2310 | while (1) { | |
2311 | set_current_state(TASK_INTERRUPTIBLE); | |
2312 | if (signal_pending(current)) { | |
2313 | retval = -ERESTARTSYS; | |
2314 | break; | |
2315 | } | |
2316 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2317 | retval = -EIO; | |
2318 | break; | |
2319 | } | |
582f5590 | 2320 | if (O_OPOST(tty)) { |
1da177e4 | 2321 | while (nr > 0) { |
a88a69c9 | 2322 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2323 | if (num < 0) { |
2324 | if (num == -EAGAIN) | |
2325 | break; | |
2326 | retval = num; | |
2327 | goto break_out; | |
2328 | } | |
2329 | b += num; | |
2330 | nr -= num; | |
2331 | if (nr == 0) | |
2332 | break; | |
2333 | c = *b; | |
a88a69c9 | 2334 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2335 | break; |
2336 | b++; nr--; | |
2337 | } | |
f34d7a5b AC |
2338 | if (tty->ops->flush_chars) |
2339 | tty->ops->flush_chars(tty); | |
1da177e4 | 2340 | } else { |
d6afe27b | 2341 | while (nr > 0) { |
f34d7a5b | 2342 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
2343 | if (c < 0) { |
2344 | retval = c; | |
2345 | goto break_out; | |
2346 | } | |
2347 | if (!c) | |
2348 | break; | |
2349 | b += c; | |
2350 | nr -= c; | |
1da177e4 | 2351 | } |
1da177e4 LT |
2352 | } |
2353 | if (!nr) | |
2354 | break; | |
2355 | if (file->f_flags & O_NONBLOCK) { | |
2356 | retval = -EAGAIN; | |
2357 | break; | |
2358 | } | |
9356b535 PH |
2359 | up_read(&tty->termios_rwsem); |
2360 | ||
1da177e4 | 2361 | schedule(); |
9356b535 PH |
2362 | |
2363 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2364 | } |
2365 | break_out: | |
2366 | __set_current_state(TASK_RUNNING); | |
2367 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2368 | if (b - buf != nr && tty->fasync) |
2369 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2370 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2371 | return (b - buf) ? b - buf : retval; |
2372 | } | |
2373 | ||
2374 | /** | |
11a96d18 | 2375 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2376 | * @tty: terminal device |
2377 | * @file: file accessing it | |
2378 | * @wait: poll table | |
2379 | * | |
2380 | * Called when the line discipline is asked to poll() for data or | |
2381 | * for special events. This code is not serialized with respect to | |
2382 | * other events save open/close. | |
2383 | * | |
2384 | * This code must be sure never to sleep through a hangup. | |
2385 | * Called without the kernel lock held - fine | |
1da177e4 | 2386 | */ |
4edf1827 | 2387 | |
11a96d18 | 2388 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2389 | poll_table *wait) |
1da177e4 | 2390 | { |
f6c8dbe6 | 2391 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2392 | unsigned int mask = 0; |
2393 | ||
2394 | poll_wait(file, &tty->read_wait, wait); | |
2395 | poll_wait(file, &tty->write_wait, wait); | |
2396 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2397 | mask |= POLLIN | POLLRDNORM; | |
2398 | if (tty->packet && tty->link->ctrl_status) | |
2399 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2400 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2401 | mask |= POLLHUP; | |
2402 | if (tty_hung_up_p(file)) | |
2403 | mask |= POLLHUP; | |
2404 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2405 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2406 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2407 | else |
f6c8dbe6 | 2408 | ldata->minimum_to_wake = 1; |
1da177e4 | 2409 | } |
f34d7a5b AC |
2410 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2411 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2412 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2413 | mask |= POLLOUT | POLLWRNORM; |
2414 | return mask; | |
2415 | } | |
2416 | ||
57c94121 | 2417 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2418 | { |
bc5a5e3f | 2419 | size_t nr, head, tail; |
47afa7a5 | 2420 | |
a73d3d69 | 2421 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2422 | return 0; |
ba2e68ac JS |
2423 | head = ldata->canon_head; |
2424 | tail = ldata->read_tail; | |
bc5a5e3f | 2425 | nr = head - tail; |
47afa7a5 AC |
2426 | /* Skip EOF-chars.. */ |
2427 | while (head != tail) { | |
bc5a5e3f PH |
2428 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2429 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2430 | nr--; |
bc5a5e3f | 2431 | tail++; |
47afa7a5 AC |
2432 | } |
2433 | return nr; | |
2434 | } | |
2435 | ||
2436 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2437 | unsigned int cmd, unsigned long arg) | |
2438 | { | |
ba2e68ac | 2439 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2440 | int retval; |
2441 | ||
2442 | switch (cmd) { | |
2443 | case TIOCOUTQ: | |
2444 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2445 | case TIOCINQ: | |
6d76bd26 | 2446 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2447 | if (L_ICANON(tty)) |
57c94121 | 2448 | retval = inq_canon(ldata); |
6d76bd26 PH |
2449 | else |
2450 | retval = read_cnt(ldata); | |
2451 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2452 | return put_user(retval, (unsigned int __user *) arg); |
2453 | default: | |
2454 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2455 | } | |
2456 | } | |
2457 | ||
f6c8dbe6 PH |
2458 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2459 | { | |
2460 | struct n_tty_data *ldata = tty->disc_data; | |
2461 | ||
2462 | if (!waitqueue_active(&tty->read_wait)) { | |
2463 | if (on) | |
2464 | ldata->minimum_to_wake = 1; | |
2465 | else if (!tty->fasync) | |
2466 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2467 | } | |
2468 | } | |
2469 | ||
a352def2 | 2470 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2471 | .magic = TTY_LDISC_MAGIC, |
2472 | .name = "n_tty", | |
2473 | .open = n_tty_open, | |
2474 | .close = n_tty_close, | |
2475 | .flush_buffer = n_tty_flush_buffer, | |
2476 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2477 | .read = n_tty_read, |
2478 | .write = n_tty_write, | |
e10cc1df PF |
2479 | .ioctl = n_tty_ioctl, |
2480 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2481 | .poll = n_tty_poll, |
e10cc1df | 2482 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2483 | .write_wakeup = n_tty_write_wakeup, |
2484 | .fasync = n_tty_fasync, | |
24a89d1c | 2485 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2486 | }; |
572b9adb RG |
2487 | |
2488 | /** | |
2489 | * n_tty_inherit_ops - inherit N_TTY methods | |
2490 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2491 | * | |
593fb1ae | 2492 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2493 | * methods. |
2494 | */ | |
2495 | ||
2496 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2497 | { | |
2498 | *ops = tty_ldisc_N_TTY; | |
2499 | ops->owner = NULL; | |
2500 | ops->refcount = ops->flags = 0; | |
2501 | } | |
2502 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |