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; | |
1075a6e2 | 96 | size_t echo_mark; |
1bb9d562 | 97 | DECLARE_BITMAP(char_map, 256); |
fb7aa03d PH |
98 | |
99 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c JS |
100 | unsigned long overrun_time; |
101 | int num_overrun; | |
102 | ||
24a89d1c PH |
103 | /* non-atomic */ |
104 | bool no_room; | |
105 | ||
fb7aa03d | 106 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c | 107 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
3fe780b3 | 108 | |
fb7aa03d | 109 | /* shared by producer and consumer */ |
20bafb3d | 110 | char read_buf[N_TTY_BUF_SIZE]; |
3fe780b3 | 111 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
20bafb3d | 112 | unsigned char echo_buf[N_TTY_BUF_SIZE]; |
ba2e68ac | 113 | |
f6c8dbe6 | 114 | int minimum_to_wake; |
ba2e68ac | 115 | |
fb7aa03d PH |
116 | /* consumer-published */ |
117 | size_t read_tail; | |
40d5e090 | 118 | size_t line_start; |
fb7aa03d | 119 | |
fb7aa03d PH |
120 | /* protected by output lock */ |
121 | unsigned int column; | |
ba2e68ac | 122 | unsigned int canon_column; |
9dfd16dd | 123 | size_t echo_tail; |
bddc7152 JS |
124 | |
125 | struct mutex atomic_read_lock; | |
126 | struct mutex output_lock; | |
70ece7a7 JS |
127 | }; |
128 | ||
ce74117a PH |
129 | static inline size_t read_cnt(struct n_tty_data *ldata) |
130 | { | |
a2f73be8 | 131 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
132 | } |
133 | ||
bc5a5e3f PH |
134 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
135 | { | |
136 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
137 | } | |
138 | ||
139 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
140 | { | |
141 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
142 | } | |
143 | ||
addaebcc PH |
144 | static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) |
145 | { | |
146 | return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
147 | } | |
148 | ||
149 | static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) | |
150 | { | |
151 | return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
152 | } | |
153 | ||
522ed776 MT |
154 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
155 | unsigned char __user *ptr) | |
156 | { | |
53c5ee2c JS |
157 | struct n_tty_data *ldata = tty->disc_data; |
158 | ||
159 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
160 | return put_user(x, ptr); |
161 | } | |
162 | ||
24a89d1c | 163 | static int receive_room(struct tty_struct *tty) |
55db4c64 | 164 | { |
53c5ee2c | 165 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 166 | int left; |
55db4c64 | 167 | |
090abf7b JA |
168 | if (I_PARMRK(tty)) { |
169 | /* Multiply read_cnt by 3, since each byte might take up to | |
170 | * three times as many spaces when PARMRK is set (depending on | |
171 | * its flags, e.g. parity error). */ | |
ce74117a | 172 | left = N_TTY_BUF_SIZE - read_cnt(ldata) * 3 - 1; |
090abf7b | 173 | } else |
ce74117a | 174 | left = N_TTY_BUF_SIZE - read_cnt(ldata) - 1; |
090abf7b | 175 | |
55db4c64 LT |
176 | /* |
177 | * If we are doing input canonicalization, and there are no | |
178 | * pending newlines, let characters through without limit, so | |
179 | * that erase characters will be handled. Other excess | |
180 | * characters will be beeped. | |
181 | */ | |
182 | if (left <= 0) | |
a73d3d69 | 183 | left = ldata->icanon && ldata->canon_head == ldata->read_tail; |
55db4c64 | 184 | |
24a89d1c | 185 | return left; |
7879a9f9 PH |
186 | } |
187 | ||
24a89d1c PH |
188 | /** |
189 | * n_tty_set_room - receive space | |
190 | * @tty: terminal | |
191 | * | |
192 | * Re-schedules the flip buffer work if space just became available. | |
193 | * | |
6d76bd26 PH |
194 | * Caller holds exclusive termios_rwsem |
195 | * or | |
196 | * n_tty_read()/consumer path: | |
197 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
198 | */ |
199 | ||
7879a9f9 PH |
200 | static void n_tty_set_room(struct tty_struct *tty) |
201 | { | |
24a89d1c PH |
202 | struct n_tty_data *ldata = tty->disc_data; |
203 | ||
55db4c64 | 204 | /* Did this open up the receive buffer? We may need to flip */ |
24a89d1c PH |
205 | if (unlikely(ldata->no_room) && receive_room(tty)) { |
206 | ldata->no_room = 0; | |
207 | ||
ecbbfd44 | 208 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 209 | "scheduling with invalid itty\n"); |
21622939 PH |
210 | /* see if ldisc has been killed - if so, this means that |
211 | * even though the ldisc has been halted and ->buf.work | |
212 | * cancelled, ->buf.work is about to be rescheduled | |
213 | */ | |
214 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
215 | "scheduling buffer work for halted ldisc\n"); | |
f0f947c1 | 216 | queue_work(system_unbound_wq, &tty->port->buf.work); |
ecbbfd44 | 217 | } |
55db4c64 LT |
218 | } |
219 | ||
9a4aec2d PH |
220 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
221 | { | |
222 | struct n_tty_data *ldata = tty->disc_data; | |
223 | ssize_t n = 0; | |
224 | ||
225 | if (!ldata->icanon) | |
226 | n = read_cnt(ldata); | |
227 | else | |
228 | n = ldata->canon_head - ldata->read_tail; | |
229 | return n; | |
230 | } | |
231 | ||
ee0bab83 PH |
232 | /** |
233 | * n_tty_write_wakeup - asynchronous I/O notifier | |
234 | * @tty: tty device | |
235 | * | |
236 | * Required for the ptys, serial driver etc. since processes | |
237 | * that attach themselves to the master and rely on ASYNC | |
238 | * IO must be woken up | |
239 | */ | |
240 | ||
241 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
242 | { | |
243 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) | |
244 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
245 | } | |
246 | ||
4a23a4df | 247 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 248 | { |
3afb1b39 PH |
249 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) |
250 | return; | |
6367ca72 PH |
251 | /* |
252 | * Check the remaining room for the input canonicalization | |
253 | * mode. We don't want to throttle the driver if we're in | |
254 | * canonical mode and don't have a newline yet! | |
255 | */ | |
256 | while (1) { | |
257 | int throttled; | |
258 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
259 | if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) | |
260 | break; | |
261 | throttled = tty_throttle_safe(tty); | |
262 | if (!throttled) | |
263 | break; | |
264 | } | |
265 | __tty_set_flow_change(tty, 0); | |
266 | } | |
267 | ||
4b293492 | 268 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 269 | { |
3afb1b39 PH |
270 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
271 | tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { | |
272 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
273 | return; | |
274 | if (!tty->count) | |
275 | return; | |
276 | n_tty_set_room(tty); | |
277 | n_tty_write_wakeup(tty->link); | |
278 | wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); | |
279 | return; | |
280 | } | |
281 | ||
6367ca72 PH |
282 | /* If there is enough space in the read buffer now, let the |
283 | * low-level driver know. We use chars_in_buffer() to | |
284 | * check the buffer, as it now knows about canonical mode. | |
285 | * Otherwise, if the driver is throttled and the line is | |
286 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
287 | * we won't get any more characters. | |
288 | */ | |
289 | ||
290 | while (1) { | |
291 | int unthrottled; | |
292 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
293 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
294 | break; | |
295 | if (!tty->count) | |
296 | break; | |
297 | n_tty_set_room(tty); | |
298 | unthrottled = tty_unthrottle_safe(tty); | |
299 | if (!unthrottled) | |
300 | break; | |
301 | } | |
302 | __tty_set_flow_change(tty, 0); | |
303 | } | |
304 | ||
17b82060 AC |
305 | /** |
306 | * put_tty_queue - add character to tty | |
307 | * @c: character | |
57c94121 | 308 | * @ldata: n_tty data |
17b82060 | 309 | * |
6d76bd26 PH |
310 | * Add a character to the tty read_buf queue. |
311 | * | |
312 | * n_tty_receive_buf()/producer path: | |
313 | * caller holds non-exclusive termios_rwsem | |
314 | * modifies read_head | |
315 | * | |
316 | * read_head is only considered 'published' if canonical mode is | |
317 | * not active. | |
17b82060 AC |
318 | */ |
319 | ||
19e2ad6a | 320 | static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 321 | { |
19e2ad6a | 322 | *read_buf_addr(ldata, ldata->read_head++) = c; |
1da177e4 LT |
323 | } |
324 | ||
1da177e4 LT |
325 | /** |
326 | * reset_buffer_flags - reset buffer state | |
327 | * @tty: terminal to reset | |
328 | * | |
25518c68 PH |
329 | * Reset the read buffer counters and clear the flags. |
330 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 331 | * |
6d76bd26 PH |
332 | * Locking: caller holds exclusive termios_rwsem |
333 | * (or locking is not required) | |
1da177e4 | 334 | */ |
a88a69c9 | 335 | |
b66f4fa5 | 336 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 337 | { |
a73d3d69 | 338 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 339 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
1075a6e2 | 340 | ldata->echo_mark = 0; |
40d5e090 | 341 | ldata->line_start = 0; |
a88a69c9 | 342 | |
a73d3d69 | 343 | ldata->erasing = 0; |
3fe780b3 | 344 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
1da177e4 LT |
345 | } |
346 | ||
a30737ab PH |
347 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
348 | { | |
349 | unsigned long flags; | |
350 | ||
351 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
352 | if (tty->link->packet) { | |
353 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
354 | wake_up_interruptible(&tty->link->read_wait); | |
355 | } | |
356 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
357 | } | |
358 | ||
1da177e4 LT |
359 | /** |
360 | * n_tty_flush_buffer - clean input queue | |
361 | * @tty: terminal device | |
362 | * | |
25518c68 PH |
363 | * Flush the input buffer. Called when the tty layer wants the |
364 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
365 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 366 | * |
6d76bd26 PH |
367 | * Holds termios_rwsem to exclude producer/consumer while |
368 | * buffer indices are reset. | |
369 | * | |
370 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 371 | */ |
4edf1827 AC |
372 | |
373 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 374 | { |
6d76bd26 | 375 | down_write(&tty->termios_rwsem); |
b66f4fa5 PH |
376 | reset_buffer_flags(tty->disc_data); |
377 | n_tty_set_room(tty); | |
4edf1827 | 378 | |
a30737ab PH |
379 | if (tty->link) |
380 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 381 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
382 | } |
383 | ||
6d76bd26 PH |
384 | /** |
385 | * n_tty_chars_in_buffer - report available bytes | |
386 | * @tty: tty device | |
387 | * | |
388 | * Report the number of characters buffered to be delivered to user | |
389 | * at this instant in time. | |
390 | * | |
391 | * Locking: exclusive termios_rwsem | |
392 | */ | |
393 | ||
a19d0c6a PH |
394 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
395 | { | |
6d76bd26 PH |
396 | ssize_t n; |
397 | ||
47534084 | 398 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
6d76bd26 PH |
399 | |
400 | down_write(&tty->termios_rwsem); | |
401 | n = chars_in_buffer(tty); | |
402 | up_write(&tty->termios_rwsem); | |
403 | return n; | |
a19d0c6a PH |
404 | } |
405 | ||
1da177e4 LT |
406 | /** |
407 | * is_utf8_continuation - utf8 multibyte check | |
408 | * @c: byte to check | |
409 | * | |
410 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
411 | * character. We use this to correctly compute the on screen size | |
412 | * of the character when printing | |
413 | */ | |
4edf1827 | 414 | |
1da177e4 LT |
415 | static inline int is_utf8_continuation(unsigned char c) |
416 | { | |
417 | return (c & 0xc0) == 0x80; | |
418 | } | |
419 | ||
420 | /** | |
421 | * is_continuation - multibyte check | |
422 | * @c: byte to check | |
423 | * | |
424 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
425 | * character and the terminal is in unicode mode. | |
426 | */ | |
4edf1827 | 427 | |
1da177e4 LT |
428 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
429 | { | |
430 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
431 | } | |
432 | ||
433 | /** | |
a88a69c9 | 434 | * do_output_char - output one character |
1da177e4 LT |
435 | * @c: character (or partial unicode symbol) |
436 | * @tty: terminal device | |
a88a69c9 | 437 | * @space: space available in tty driver write buffer |
1da177e4 | 438 | * |
a88a69c9 JP |
439 | * This is a helper function that handles one output character |
440 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
441 | * doing OPOST processing and putting the results in the |
442 | * tty driver's write buffer. | |
a88a69c9 JP |
443 | * |
444 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
445 | * and NLDLY. They simply aren't relevant in the world today. | |
446 | * If you ever need them, add them here. | |
1da177e4 | 447 | * |
a88a69c9 JP |
448 | * Returns the number of bytes of buffer space used or -1 if |
449 | * no space left. | |
450 | * | |
451 | * Locking: should be called under the output_lock to protect | |
452 | * the column state and space left in the buffer | |
1da177e4 | 453 | */ |
4edf1827 | 454 | |
a88a69c9 | 455 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 456 | { |
53c5ee2c | 457 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 458 | int spaces; |
1da177e4 | 459 | |
1da177e4 LT |
460 | if (!space) |
461 | return -1; | |
300a6204 | 462 | |
a88a69c9 JP |
463 | switch (c) { |
464 | case '\n': | |
465 | if (O_ONLRET(tty)) | |
53c5ee2c | 466 | ldata->column = 0; |
a88a69c9 JP |
467 | if (O_ONLCR(tty)) { |
468 | if (space < 2) | |
469 | return -1; | |
ba2e68ac | 470 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 471 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
472 | return 2; |
473 | } | |
ba2e68ac | 474 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
475 | break; |
476 | case '\r': | |
53c5ee2c | 477 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
478 | return 0; |
479 | if (O_OCRNL(tty)) { | |
480 | c = '\n'; | |
481 | if (O_ONLRET(tty)) | |
ba2e68ac | 482 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 483 | break; |
a88a69c9 | 484 | } |
ba2e68ac | 485 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
486 | break; |
487 | case '\t': | |
53c5ee2c | 488 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
489 | if (O_TABDLY(tty) == XTABS) { |
490 | if (space < spaces) | |
491 | return -1; | |
53c5ee2c | 492 | ldata->column += spaces; |
a88a69c9 JP |
493 | tty->ops->write(tty, " ", spaces); |
494 | return spaces; | |
1da177e4 | 495 | } |
53c5ee2c | 496 | ldata->column += spaces; |
a88a69c9 JP |
497 | break; |
498 | case '\b': | |
53c5ee2c JS |
499 | if (ldata->column > 0) |
500 | ldata->column--; | |
a88a69c9 JP |
501 | break; |
502 | default: | |
a59c0d6f JP |
503 | if (!iscntrl(c)) { |
504 | if (O_OLCUC(tty)) | |
505 | c = toupper(c); | |
506 | if (!is_continuation(c, tty)) | |
53c5ee2c | 507 | ldata->column++; |
a59c0d6f | 508 | } |
a88a69c9 | 509 | break; |
1da177e4 | 510 | } |
a88a69c9 | 511 | |
f34d7a5b | 512 | tty_put_char(tty, c); |
a88a69c9 JP |
513 | return 1; |
514 | } | |
515 | ||
516 | /** | |
517 | * process_output - output post processor | |
518 | * @c: character (or partial unicode symbol) | |
519 | * @tty: terminal device | |
520 | * | |
ee5aa7b8 JP |
521 | * Output one character with OPOST processing. |
522 | * Returns -1 when the output device is full and the character | |
523 | * must be retried. | |
a88a69c9 JP |
524 | * |
525 | * Locking: output_lock to protect column state and space left | |
526 | * (also, this is called from n_tty_write under the | |
527 | * tty layer write lock) | |
528 | */ | |
529 | ||
530 | static int process_output(unsigned char c, struct tty_struct *tty) | |
531 | { | |
bddc7152 | 532 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
533 | int space, retval; |
534 | ||
bddc7152 | 535 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
536 | |
537 | space = tty_write_room(tty); | |
538 | retval = do_output_char(c, tty, space); | |
539 | ||
bddc7152 | 540 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
541 | if (retval < 0) |
542 | return -1; | |
543 | else | |
544 | return 0; | |
1da177e4 LT |
545 | } |
546 | ||
547 | /** | |
a88a69c9 | 548 | * process_output_block - block post processor |
1da177e4 | 549 | * @tty: terminal device |
ee5aa7b8 JP |
550 | * @buf: character buffer |
551 | * @nr: number of bytes to output | |
552 | * | |
553 | * Output a block of characters with OPOST processing. | |
554 | * Returns the number of characters output. | |
1da177e4 LT |
555 | * |
556 | * This path is used to speed up block console writes, among other | |
557 | * things when processing blocks of output data. It handles only | |
558 | * the simple cases normally found and helps to generate blocks of | |
559 | * symbols for the console driver and thus improve performance. | |
560 | * | |
a88a69c9 JP |
561 | * Locking: output_lock to protect column state and space left |
562 | * (also, this is called from n_tty_write under the | |
563 | * tty layer write lock) | |
1da177e4 | 564 | */ |
4edf1827 | 565 | |
a88a69c9 JP |
566 | static ssize_t process_output_block(struct tty_struct *tty, |
567 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 568 | { |
53c5ee2c | 569 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 570 | int space; |
bbd20759 | 571 | int i; |
1da177e4 LT |
572 | const unsigned char *cp; |
573 | ||
bddc7152 | 574 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 575 | |
f34d7a5b | 576 | space = tty_write_room(tty); |
300a6204 | 577 | if (!space) { |
bddc7152 | 578 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 579 | return 0; |
a88a69c9 | 580 | } |
1da177e4 LT |
581 | if (nr > space) |
582 | nr = space; | |
583 | ||
584 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
585 | unsigned char c = *cp; |
586 | ||
587 | switch (c) { | |
1da177e4 LT |
588 | case '\n': |
589 | if (O_ONLRET(tty)) | |
53c5ee2c | 590 | ldata->column = 0; |
1da177e4 LT |
591 | if (O_ONLCR(tty)) |
592 | goto break_out; | |
ba2e68ac | 593 | ldata->canon_column = ldata->column; |
1da177e4 LT |
594 | break; |
595 | case '\r': | |
53c5ee2c | 596 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
597 | goto break_out; |
598 | if (O_OCRNL(tty)) | |
599 | goto break_out; | |
ba2e68ac | 600 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
601 | break; |
602 | case '\t': | |
603 | goto break_out; | |
604 | case '\b': | |
53c5ee2c JS |
605 | if (ldata->column > 0) |
606 | ldata->column--; | |
1da177e4 LT |
607 | break; |
608 | default: | |
a59c0d6f JP |
609 | if (!iscntrl(c)) { |
610 | if (O_OLCUC(tty)) | |
611 | goto break_out; | |
612 | if (!is_continuation(c, tty)) | |
53c5ee2c | 613 | ldata->column++; |
a59c0d6f | 614 | } |
1da177e4 LT |
615 | break; |
616 | } | |
617 | } | |
618 | break_out: | |
f34d7a5b | 619 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 620 | |
bddc7152 | 621 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
622 | return i; |
623 | } | |
624 | ||
a88a69c9 JP |
625 | /** |
626 | * process_echoes - write pending echo characters | |
627 | * @tty: terminal device | |
628 | * | |
629 | * Write previously buffered echo (and other ldisc-generated) | |
630 | * characters to the tty. | |
631 | * | |
632 | * Characters generated by the ldisc (including echoes) need to | |
633 | * be buffered because the driver's write buffer can fill during | |
634 | * heavy program output. Echoing straight to the driver will | |
635 | * often fail under these conditions, causing lost characters and | |
636 | * resulting mismatches of ldisc state information. | |
637 | * | |
638 | * Since the ldisc state must represent the characters actually sent | |
639 | * to the driver at the time of the write, operations like certain | |
640 | * changes in column state are also saved in the buffer and executed | |
641 | * here. | |
642 | * | |
643 | * A circular fifo buffer is used so that the most recent characters | |
644 | * are prioritized. Also, when control characters are echoed with a | |
645 | * prefixed "^", the pair is treated atomically and thus not separated. | |
646 | * | |
019ebdf9 | 647 | * Locking: callers must hold output_lock |
a88a69c9 JP |
648 | */ |
649 | ||
bc5b1ec5 | 650 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 651 | { |
53c5ee2c | 652 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 653 | int space, old_space; |
addaebcc | 654 | size_t tail; |
a88a69c9 | 655 | unsigned char c; |
a88a69c9 | 656 | |
bc5b1ec5 | 657 | old_space = space = tty_write_room(tty); |
a88a69c9 | 658 | |
addaebcc | 659 | tail = ldata->echo_tail; |
29c7c5ca | 660 | while (ldata->echo_commit != tail) { |
addaebcc | 661 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
662 | if (c == ECHO_OP_START) { |
663 | unsigned char op; | |
a88a69c9 JP |
664 | int no_space_left = 0; |
665 | ||
666 | /* | |
667 | * If the buffer byte is the start of a multi-byte | |
668 | * operation, get the next byte, which is either the | |
669 | * op code or a control character value. | |
670 | */ | |
addaebcc | 671 | op = echo_buf(ldata, tail + 1); |
300a6204 | 672 | |
a88a69c9 JP |
673 | switch (op) { |
674 | unsigned int num_chars, num_bs; | |
675 | ||
676 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 677 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
678 | |
679 | /* | |
680 | * Determine how many columns to go back | |
681 | * in order to erase the tab. | |
682 | * This depends on the number of columns | |
683 | * used by other characters within the tab | |
684 | * area. If this (modulo 8) count is from | |
685 | * the start of input rather than from a | |
686 | * previous tab, we offset by canon column. | |
687 | * Otherwise, tab spacing is normal. | |
688 | */ | |
689 | if (!(num_chars & 0x80)) | |
ba2e68ac | 690 | num_chars += ldata->canon_column; |
a88a69c9 JP |
691 | num_bs = 8 - (num_chars & 7); |
692 | ||
693 | if (num_bs > space) { | |
694 | no_space_left = 1; | |
695 | break; | |
696 | } | |
697 | space -= num_bs; | |
698 | while (num_bs--) { | |
699 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
700 | if (ldata->column > 0) |
701 | ldata->column--; | |
a88a69c9 | 702 | } |
addaebcc | 703 | tail += 3; |
a88a69c9 JP |
704 | break; |
705 | ||
706 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 707 | ldata->canon_column = ldata->column; |
addaebcc | 708 | tail += 2; |
a88a69c9 JP |
709 | break; |
710 | ||
711 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
712 | if (ldata->column > 0) |
713 | ldata->column--; | |
addaebcc | 714 | tail += 2; |
a88a69c9 JP |
715 | break; |
716 | ||
717 | case ECHO_OP_START: | |
718 | /* This is an escaped echo op start code */ | |
719 | if (!space) { | |
720 | no_space_left = 1; | |
721 | break; | |
722 | } | |
723 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 724 | ldata->column++; |
a88a69c9 | 725 | space--; |
addaebcc | 726 | tail += 2; |
a88a69c9 JP |
727 | break; |
728 | ||
729 | default: | |
a88a69c9 | 730 | /* |
62b26358 JP |
731 | * If the op is not a special byte code, |
732 | * it is a ctrl char tagged to be echoed | |
733 | * as "^X" (where X is the letter | |
734 | * representing the control char). | |
735 | * Note that we must ensure there is | |
736 | * enough space for the whole ctrl pair. | |
737 | * | |
a88a69c9 | 738 | */ |
62b26358 JP |
739 | if (space < 2) { |
740 | no_space_left = 1; | |
741 | break; | |
742 | } | |
743 | tty_put_char(tty, '^'); | |
744 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 745 | ldata->column += 2; |
62b26358 | 746 | space -= 2; |
addaebcc | 747 | tail += 2; |
a88a69c9 JP |
748 | } |
749 | ||
750 | if (no_space_left) | |
751 | break; | |
752 | } else { | |
582f5590 | 753 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
754 | int retval = do_output_char(c, tty, space); |
755 | if (retval < 0) | |
756 | break; | |
757 | space -= retval; | |
758 | } else { | |
759 | if (!space) | |
760 | break; | |
761 | tty_put_char(tty, c); | |
762 | space -= 1; | |
763 | } | |
addaebcc | 764 | tail += 1; |
a88a69c9 | 765 | } |
a88a69c9 JP |
766 | } |
767 | ||
cbfd0340 PH |
768 | /* If the echo buffer is nearly full (so that the possibility exists |
769 | * of echo overrun before the next commit), then discard enough | |
770 | * data at the tail to prevent a subsequent overrun */ | |
771 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 772 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 773 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
774 | tail += 3; |
775 | else | |
776 | tail += 2; | |
777 | } else | |
778 | tail++; | |
779 | } | |
780 | ||
addaebcc | 781 | ldata->echo_tail = tail; |
bc5b1ec5 | 782 | return old_space - space; |
019ebdf9 PH |
783 | } |
784 | ||
785 | static void commit_echoes(struct tty_struct *tty) | |
786 | { | |
787 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 788 | size_t nr, old, echoed; |
cbfd0340 PH |
789 | size_t head; |
790 | ||
791 | head = ldata->echo_head; | |
1075a6e2 | 792 | ldata->echo_mark = head; |
cbfd0340 PH |
793 | old = ldata->echo_commit - ldata->echo_tail; |
794 | ||
795 | /* Process committed echoes if the accumulated # of bytes | |
796 | * is over the threshold (and try again each time another | |
797 | * block is accumulated) */ | |
798 | nr = head - ldata->echo_tail; | |
799 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
800 | return; | |
a88a69c9 | 801 | |
019ebdf9 | 802 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 803 | ldata->echo_commit = head; |
bc5b1ec5 | 804 | echoed = __process_echoes(tty); |
bddc7152 | 805 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 806 | |
bc5b1ec5 | 807 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
808 | tty->ops->flush_chars(tty); |
809 | } | |
810 | ||
019ebdf9 | 811 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
812 | { |
813 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 814 | size_t echoed; |
17bd7907 | 815 | |
39434abd | 816 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
1075a6e2 | 817 | ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
818 | return; |
819 | ||
820 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 821 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 822 | echoed = __process_echoes(tty); |
019ebdf9 PH |
823 | mutex_unlock(&ldata->output_lock); |
824 | ||
bc5b1ec5 | 825 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 826 | tty->ops->flush_chars(tty); |
17bd7907 PH |
827 | } |
828 | ||
1075a6e2 | 829 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
830 | static void flush_echoes(struct tty_struct *tty) |
831 | { | |
832 | struct n_tty_data *ldata = tty->disc_data; | |
833 | ||
39434abd PH |
834 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
835 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
836 | return; |
837 | ||
838 | mutex_lock(&ldata->output_lock); | |
839 | ldata->echo_commit = ldata->echo_head; | |
840 | __process_echoes(tty); | |
841 | mutex_unlock(&ldata->output_lock); | |
842 | } | |
843 | ||
a88a69c9 JP |
844 | /** |
845 | * add_echo_byte - add a byte to the echo buffer | |
846 | * @c: unicode byte to echo | |
57c94121 | 847 | * @ldata: n_tty data |
a88a69c9 JP |
848 | * |
849 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
850 | */ |
851 | ||
cbfd0340 | 852 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 853 | { |
addaebcc | 854 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
855 | } |
856 | ||
857 | /** | |
858 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 859 | * @ldata: n_tty data |
a88a69c9 JP |
860 | * |
861 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
862 | */ |
863 | ||
57c94121 | 864 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 865 | { |
57c94121 JS |
866 | add_echo_byte(ECHO_OP_START, ldata); |
867 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
868 | } |
869 | ||
870 | /** | |
871 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 872 | * @ldata: n_tty data |
a88a69c9 JP |
873 | * |
874 | * Add an operation to the echo buffer to set the canon column | |
875 | * to the current column. | |
a88a69c9 JP |
876 | */ |
877 | ||
57c94121 | 878 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 879 | { |
57c94121 JS |
880 | add_echo_byte(ECHO_OP_START, ldata); |
881 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
882 | } |
883 | ||
884 | /** | |
885 | * echo_erase_tab - add operation to erase a tab | |
886 | * @num_chars: number of character columns already used | |
887 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 888 | * @ldata: n_tty data |
a88a69c9 JP |
889 | * |
890 | * Add an operation to the echo buffer to erase a tab. | |
891 | * | |
892 | * Called by the eraser function, which knows how many character | |
893 | * columns have been used since either a previous tab or the start | |
894 | * of input. This information will be used later, along with | |
895 | * canon column (if applicable), to go back the correct number | |
896 | * of columns. | |
a88a69c9 JP |
897 | */ |
898 | ||
899 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 900 | struct n_tty_data *ldata) |
a88a69c9 | 901 | { |
57c94121 JS |
902 | add_echo_byte(ECHO_OP_START, ldata); |
903 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
904 | |
905 | /* We only need to know this modulo 8 (tab spacing) */ | |
906 | num_chars &= 7; | |
907 | ||
908 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
909 | if (after_tab) | |
910 | num_chars |= 0x80; | |
300a6204 | 911 | |
57c94121 | 912 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
913 | } |
914 | ||
915 | /** | |
916 | * echo_char_raw - echo a character raw | |
917 | * @c: unicode byte to echo | |
918 | * @tty: terminal device | |
919 | * | |
920 | * Echo user input back onto the screen. This must be called only when | |
921 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
922 | * | |
923 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
924 | */ |
925 | ||
57c94121 | 926 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 927 | { |
a88a69c9 | 928 | if (c == ECHO_OP_START) { |
57c94121 JS |
929 | add_echo_byte(ECHO_OP_START, ldata); |
930 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 931 | } else { |
57c94121 | 932 | add_echo_byte(c, ldata); |
a88a69c9 | 933 | } |
a88a69c9 | 934 | } |
1da177e4 | 935 | |
1da177e4 | 936 | /** |
a88a69c9 | 937 | * echo_char - echo a character |
1da177e4 LT |
938 | * @c: unicode byte to echo |
939 | * @tty: terminal device | |
940 | * | |
4edf1827 | 941 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 942 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 943 | * |
62b26358 JP |
944 | * This variant tags control characters to be echoed as "^X" |
945 | * (where X is the letter representing the control char). | |
1da177e4 LT |
946 | */ |
947 | ||
948 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
949 | { | |
bddc7152 JS |
950 | struct n_tty_data *ldata = tty->disc_data; |
951 | ||
a88a69c9 | 952 | if (c == ECHO_OP_START) { |
57c94121 JS |
953 | add_echo_byte(ECHO_OP_START, ldata); |
954 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 955 | } else { |
62b26358 | 956 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
957 | add_echo_byte(ECHO_OP_START, ldata); |
958 | add_echo_byte(c, ldata); | |
a88a69c9 | 959 | } |
1da177e4 LT |
960 | } |
961 | ||
17b82060 | 962 | /** |
a88a69c9 | 963 | * finish_erasing - complete erase |
57c94121 | 964 | * @ldata: n_tty data |
17b82060 | 965 | */ |
a88a69c9 | 966 | |
57c94121 | 967 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 968 | { |
53c5ee2c | 969 | if (ldata->erasing) { |
57c94121 | 970 | echo_char_raw('/', ldata); |
53c5ee2c | 971 | ldata->erasing = 0; |
1da177e4 LT |
972 | } |
973 | } | |
974 | ||
975 | /** | |
976 | * eraser - handle erase function | |
977 | * @c: character input | |
978 | * @tty: terminal device | |
979 | * | |
3a4fa0a2 | 980 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
981 | * present in the stream from the driver layer. Handles the complexities |
982 | * of UTF-8 multibyte symbols. | |
17b82060 | 983 | * |
6d76bd26 PH |
984 | * n_tty_receive_buf()/producer path: |
985 | * caller holds non-exclusive termios_rwsem | |
986 | * modifies read_head | |
987 | * | |
988 | * Modifying the read_head is not considered a publish in this context | |
989 | * because canonical mode is active -- only canon_head publishes | |
1da177e4 | 990 | */ |
4edf1827 | 991 | |
1da177e4 LT |
992 | static void eraser(unsigned char c, struct tty_struct *tty) |
993 | { | |
53c5ee2c | 994 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 995 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
996 | size_t head; |
997 | size_t cnt; | |
998 | int seen_alnums; | |
1da177e4 | 999 | |
ba2e68ac | 1000 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 1001 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
1002 | return; |
1003 | } | |
1004 | if (c == ERASE_CHAR(tty)) | |
1005 | kill_type = ERASE; | |
1006 | else if (c == WERASE_CHAR(tty)) | |
1007 | kill_type = WERASE; | |
1008 | else { | |
1009 | if (!L_ECHO(tty)) { | |
ba2e68ac | 1010 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
1011 | return; |
1012 | } | |
1013 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 1014 | ldata->read_head = ldata->canon_head; |
57c94121 | 1015 | finish_erasing(ldata); |
1da177e4 LT |
1016 | echo_char(KILL_CHAR(tty), tty); |
1017 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
1018 | if (L_ECHOK(tty)) | |
57c94121 | 1019 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1020 | return; |
1021 | } | |
1022 | kill_type = KILL; | |
1023 | } | |
1024 | ||
1025 | seen_alnums = 0; | |
ba2e68ac JS |
1026 | while (ldata->read_head != ldata->canon_head) { |
1027 | head = ldata->read_head; | |
1da177e4 LT |
1028 | |
1029 | /* erase a single possibly multibyte character */ | |
1030 | do { | |
bc5a5e3f PH |
1031 | head--; |
1032 | c = read_buf(ldata, head); | |
ba2e68ac | 1033 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1034 | |
1035 | /* do not partially erase */ | |
1036 | if (is_continuation(c, tty)) | |
1037 | break; | |
1038 | ||
1039 | if (kill_type == WERASE) { | |
1040 | /* Equivalent to BSD's ALTWERASE. */ | |
1041 | if (isalnum(c) || c == '_') | |
1042 | seen_alnums++; | |
1043 | else if (seen_alnums) | |
1044 | break; | |
1045 | } | |
bc5a5e3f | 1046 | cnt = ldata->read_head - head; |
ba2e68ac | 1047 | ldata->read_head = head; |
1da177e4 LT |
1048 | if (L_ECHO(tty)) { |
1049 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1050 | if (!ldata->erasing) { |
57c94121 | 1051 | echo_char_raw('\\', ldata); |
53c5ee2c | 1052 | ldata->erasing = 1; |
1da177e4 LT |
1053 | } |
1054 | /* if cnt > 1, output a multi-byte character */ | |
1055 | echo_char(c, tty); | |
1056 | while (--cnt > 0) { | |
bc5a5e3f PH |
1057 | head++; |
1058 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1059 | echo_move_back_col(ldata); |
1da177e4 LT |
1060 | } |
1061 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1062 | echo_char(ERASE_CHAR(tty), tty); | |
1063 | } else if (c == '\t') { | |
a88a69c9 JP |
1064 | unsigned int num_chars = 0; |
1065 | int after_tab = 0; | |
bc5a5e3f | 1066 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1067 | |
1068 | /* | |
1069 | * Count the columns used for characters | |
1070 | * since the start of input or after a | |
1071 | * previous tab. | |
1072 | * This info is used to go back the correct | |
1073 | * number of columns. | |
1074 | */ | |
ba2e68ac | 1075 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1076 | tail--; |
1077 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1078 | if (c == '\t') { |
1079 | after_tab = 1; | |
1080 | break; | |
300a6204 | 1081 | } else if (iscntrl(c)) { |
1da177e4 | 1082 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1083 | num_chars += 2; |
1084 | } else if (!is_continuation(c, tty)) { | |
1085 | num_chars++; | |
1086 | } | |
1da177e4 | 1087 | } |
57c94121 | 1088 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1089 | } else { |
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 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1096 | echo_char_raw('\b', ldata); |
1097 | echo_char_raw(' ', ldata); | |
1098 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1099 | } |
1100 | } | |
1101 | } | |
1102 | if (kill_type == ERASE) | |
1103 | break; | |
1104 | } | |
ba2e68ac | 1105 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1106 | finish_erasing(ldata); |
1da177e4 LT |
1107 | } |
1108 | ||
1109 | /** | |
1110 | * isig - handle the ISIG optio | |
1111 | * @sig: signal | |
1112 | * @tty: terminal | |
1da177e4 | 1113 | * |
8c985d18 PH |
1114 | * Called when a signal is being sent due to terminal input. |
1115 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1116 | * |
8c985d18 | 1117 | * Locking: ctrl_lock |
1da177e4 | 1118 | */ |
4edf1827 | 1119 | |
4b293492 | 1120 | static void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1121 | { |
8c985d18 PH |
1122 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1123 | if (tty_pgrp) { | |
1124 | kill_pgrp(tty_pgrp, sig, 1); | |
1125 | put_pid(tty_pgrp); | |
1da177e4 LT |
1126 | } |
1127 | } | |
1128 | ||
1129 | /** | |
1130 | * n_tty_receive_break - handle break | |
1131 | * @tty: terminal | |
1132 | * | |
1133 | * An RS232 break event has been hit in the incoming bitstream. This | |
1134 | * can cause a variety of events depending upon the termios settings. | |
1135 | * | |
6d76bd26 PH |
1136 | * n_tty_receive_buf()/producer path: |
1137 | * caller holds non-exclusive termios_rwsem | |
1138 | * publishes read_head via put_tty_queue() | |
1139 | * | |
1140 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1141 | */ |
4edf1827 | 1142 | |
4b293492 | 1143 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1144 | { |
57c94121 JS |
1145 | struct n_tty_data *ldata = tty->disc_data; |
1146 | ||
1da177e4 LT |
1147 | if (I_IGNBRK(tty)) |
1148 | return; | |
1149 | if (I_BRKINT(tty)) { | |
8c985d18 PH |
1150 | isig(SIGINT, tty); |
1151 | if (!L_NOFLSH(tty)) { | |
6d76bd26 PH |
1152 | /* flushing needs exclusive termios_rwsem */ |
1153 | up_read(&tty->termios_rwsem); | |
8c985d18 PH |
1154 | n_tty_flush_buffer(tty); |
1155 | tty_driver_flush_buffer(tty); | |
6d76bd26 | 1156 | down_read(&tty->termios_rwsem); |
8c985d18 | 1157 | } |
1da177e4 LT |
1158 | return; |
1159 | } | |
1160 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1161 | put_tty_queue('\377', ldata); |
1162 | put_tty_queue('\0', ldata); | |
1da177e4 | 1163 | } |
57c94121 | 1164 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1165 | wake_up_interruptible(&tty->read_wait); |
1166 | } | |
1167 | ||
1168 | /** | |
1169 | * n_tty_receive_overrun - handle overrun reporting | |
1170 | * @tty: terminal | |
1171 | * | |
1172 | * Data arrived faster than we could process it. While the tty | |
1173 | * driver has flagged this the bits that were missed are gone | |
1174 | * forever. | |
1175 | * | |
1176 | * Called from the receive_buf path so single threaded. Does not | |
1177 | * need locking as num_overrun and overrun_time are function | |
1178 | * private. | |
1179 | */ | |
4edf1827 | 1180 | |
4b293492 | 1181 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1182 | { |
53c5ee2c | 1183 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1184 | char buf[64]; |
1185 | ||
53c5ee2c JS |
1186 | ldata->num_overrun++; |
1187 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1188 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1189 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1190 | tty_name(tty, buf), | |
53c5ee2c JS |
1191 | ldata->num_overrun); |
1192 | ldata->overrun_time = jiffies; | |
1193 | ldata->num_overrun = 0; | |
1da177e4 LT |
1194 | } |
1195 | } | |
1196 | ||
1197 | /** | |
1198 | * n_tty_receive_parity_error - error notifier | |
1199 | * @tty: terminal device | |
1200 | * @c: character | |
1201 | * | |
1202 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1203 | * the error case if necessary. |
1204 | * | |
1205 | * n_tty_receive_buf()/producer path: | |
1206 | * caller holds non-exclusive termios_rwsem | |
1207 | * publishes read_head via put_tty_queue() | |
1da177e4 | 1208 | */ |
4b293492 | 1209 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1210 | { |
57c94121 JS |
1211 | struct n_tty_data *ldata = tty->disc_data; |
1212 | ||
4edf1827 | 1213 | if (I_IGNPAR(tty)) |
1da177e4 | 1214 | return; |
1da177e4 | 1215 | if (I_PARMRK(tty)) { |
57c94121 JS |
1216 | put_tty_queue('\377', ldata); |
1217 | put_tty_queue('\0', ldata); | |
1218 | put_tty_queue(c, ldata); | |
1da177e4 | 1219 | } else if (I_INPCK(tty)) |
57c94121 | 1220 | put_tty_queue('\0', ldata); |
1da177e4 | 1221 | else |
57c94121 | 1222 | put_tty_queue(c, ldata); |
1da177e4 LT |
1223 | wake_up_interruptible(&tty->read_wait); |
1224 | } | |
1225 | ||
b0ac50be PH |
1226 | static void |
1227 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1228 | { | |
1229 | if (!L_NOFLSH(tty)) { | |
1230 | /* flushing needs exclusive termios_rwsem */ | |
1231 | up_read(&tty->termios_rwsem); | |
1232 | n_tty_flush_buffer(tty); | |
1233 | tty_driver_flush_buffer(tty); | |
1234 | down_read(&tty->termios_rwsem); | |
1235 | } | |
1236 | if (I_IXON(tty)) | |
1237 | start_tty(tty); | |
1238 | if (L_ECHO(tty)) { | |
1239 | echo_char(c, tty); | |
1240 | commit_echoes(tty); | |
1241 | } | |
1242 | isig(signal, tty); | |
1243 | return; | |
1244 | } | |
1245 | ||
1da177e4 LT |
1246 | /** |
1247 | * n_tty_receive_char - perform processing | |
1248 | * @tty: terminal device | |
1249 | * @c: character | |
1250 | * | |
1251 | * Process an individual character of input received from the driver. | |
4edf1827 | 1252 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1253 | * driver above. |
6d76bd26 PH |
1254 | * |
1255 | * n_tty_receive_buf()/producer path: | |
1256 | * caller holds non-exclusive termios_rwsem | |
1257 | * publishes canon_head if canonical mode is active | |
1258 | * otherwise, publishes read_head via put_tty_queue() | |
e60d27c4 PH |
1259 | * |
1260 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1261 | */ |
1262 | ||
e60d27c4 | 1263 | static int |
4b1f79c2 | 1264 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1265 | { |
53c5ee2c | 1266 | struct n_tty_data *ldata = tty->disc_data; |
acc71bba | 1267 | int parmrk; |
1da177e4 | 1268 | |
1da177e4 LT |
1269 | if (I_IXON(tty)) { |
1270 | if (c == START_CHAR(tty)) { | |
1271 | start_tty(tty); | |
17bd7907 | 1272 | commit_echoes(tty); |
e60d27c4 | 1273 | return 0; |
1da177e4 LT |
1274 | } |
1275 | if (c == STOP_CHAR(tty)) { | |
1276 | stop_tty(tty); | |
e60d27c4 | 1277 | return 0; |
1da177e4 LT |
1278 | } |
1279 | } | |
575537b3 | 1280 | |
1da177e4 | 1281 | if (L_ISIG(tty)) { |
b0ac50be PH |
1282 | if (c == INTR_CHAR(tty)) { |
1283 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1284 | return 0; |
b0ac50be PH |
1285 | } else if (c == QUIT_CHAR(tty)) { |
1286 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1287 | return 0; |
b0ac50be PH |
1288 | } else if (c == SUSP_CHAR(tty)) { |
1289 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1290 | return 0; |
1da177e4 LT |
1291 | } |
1292 | } | |
575537b3 | 1293 | |
855df3c0 PH |
1294 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1295 | start_tty(tty); | |
1296 | process_echoes(tty); | |
1297 | } | |
1298 | ||
575537b3 JP |
1299 | if (c == '\r') { |
1300 | if (I_IGNCR(tty)) | |
e60d27c4 | 1301 | return 0; |
575537b3 JP |
1302 | if (I_ICRNL(tty)) |
1303 | c = '\n'; | |
1304 | } else if (c == '\n' && I_INLCR(tty)) | |
1305 | c = '\r'; | |
1306 | ||
53c5ee2c | 1307 | if (ldata->icanon) { |
1da177e4 LT |
1308 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1309 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1310 | eraser(c, tty); | |
17bd7907 | 1311 | commit_echoes(tty); |
e60d27c4 | 1312 | return 0; |
1da177e4 LT |
1313 | } |
1314 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1315 | ldata->lnext = 1; |
1da177e4 | 1316 | if (L_ECHO(tty)) { |
57c94121 | 1317 | finish_erasing(ldata); |
1da177e4 | 1318 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1319 | echo_char_raw('^', ldata); |
1320 | echo_char_raw('\b', ldata); | |
17bd7907 | 1321 | commit_echoes(tty); |
1da177e4 LT |
1322 | } |
1323 | } | |
e60d27c4 | 1324 | return 1; |
1da177e4 | 1325 | } |
e60d27c4 | 1326 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1327 | size_t tail = ldata->canon_head; |
1da177e4 | 1328 | |
57c94121 | 1329 | finish_erasing(ldata); |
1da177e4 | 1330 | echo_char(c, tty); |
57c94121 | 1331 | echo_char_raw('\n', ldata); |
ba2e68ac | 1332 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1333 | echo_char(read_buf(ldata, tail), tty); |
1334 | tail++; | |
1da177e4 | 1335 | } |
17bd7907 | 1336 | commit_echoes(tty); |
e60d27c4 | 1337 | return 0; |
1da177e4 LT |
1338 | } |
1339 | if (c == '\n') { | |
acc71bba | 1340 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1341 | echo_char_raw('\n', ldata); |
17bd7907 | 1342 | commit_echoes(tty); |
1da177e4 LT |
1343 | } |
1344 | goto handle_newline; | |
1345 | } | |
1346 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1347 | c = __DISABLED_CHAR; |
1348 | goto handle_newline; | |
1349 | } | |
1350 | if ((c == EOL_CHAR(tty)) || | |
1351 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1352 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1353 | ? 1 : 0; | |
1da177e4 LT |
1354 | /* |
1355 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1356 | */ | |
1357 | if (L_ECHO(tty)) { | |
1da177e4 | 1358 | /* Record the column of first canon char. */ |
ba2e68ac | 1359 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1360 | echo_set_canon_col(ldata); |
1da177e4 | 1361 | echo_char(c, tty); |
17bd7907 | 1362 | commit_echoes(tty); |
1da177e4 LT |
1363 | } |
1364 | /* | |
1365 | * XXX does PARMRK doubling happen for | |
1366 | * EOL_CHAR and EOL2_CHAR? | |
1367 | */ | |
acc71bba | 1368 | if (parmrk) |
57c94121 | 1369 | put_tty_queue(c, ldata); |
1da177e4 | 1370 | |
4edf1827 | 1371 | handle_newline: |
bc5a5e3f | 1372 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1373 | put_tty_queue(c, ldata); |
ba2e68ac | 1374 | ldata->canon_head = ldata->read_head; |
1da177e4 LT |
1375 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1376 | if (waitqueue_active(&tty->read_wait)) | |
1377 | wake_up_interruptible(&tty->read_wait); | |
e60d27c4 | 1378 | return 0; |
1da177e4 LT |
1379 | } |
1380 | } | |
4edf1827 | 1381 | |
acc71bba | 1382 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
acc71bba | 1383 | if (L_ECHO(tty)) { |
57c94121 | 1384 | finish_erasing(ldata); |
1da177e4 | 1385 | if (c == '\n') |
57c94121 | 1386 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1387 | else { |
1388 | /* Record the column of first canon char. */ | |
ba2e68ac | 1389 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1390 | echo_set_canon_col(ldata); |
1da177e4 LT |
1391 | echo_char(c, tty); |
1392 | } | |
17bd7907 | 1393 | commit_echoes(tty); |
1da177e4 LT |
1394 | } |
1395 | ||
acc71bba | 1396 | if (parmrk) |
57c94121 | 1397 | put_tty_queue(c, ldata); |
1da177e4 | 1398 | |
57c94121 | 1399 | put_tty_queue(c, ldata); |
e60d27c4 | 1400 | return 0; |
4edf1827 | 1401 | } |
1da177e4 | 1402 | |
e60d27c4 PH |
1403 | static inline void |
1404 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1405 | { |
1406 | struct n_tty_data *ldata = tty->disc_data; | |
1407 | int parmrk; | |
1408 | ||
e60d27c4 PH |
1409 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1410 | start_tty(tty); | |
1411 | process_echoes(tty); | |
1412 | } | |
1413 | if (L_ECHO(tty)) { | |
1414 | finish_erasing(ldata); | |
1415 | /* Record the column of first canon char. */ | |
1416 | if (ldata->canon_head == ldata->read_head) | |
1417 | echo_set_canon_col(ldata); | |
1418 | echo_char(c, tty); | |
1419 | commit_echoes(tty); | |
4b1f79c2 | 1420 | } |
e60d27c4 PH |
1421 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
1422 | if (parmrk) | |
1423 | put_tty_queue(c, ldata); | |
1424 | put_tty_queue(c, ldata); | |
1425 | } | |
4b1f79c2 | 1426 | |
e60d27c4 PH |
1427 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
1428 | { | |
1429 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1430 | } |
1431 | ||
7de971b0 PH |
1432 | static inline void |
1433 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1434 | { | |
1435 | struct n_tty_data *ldata = tty->disc_data; | |
1436 | ||
e60d27c4 PH |
1437 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1438 | start_tty(tty); | |
1439 | process_echoes(tty); | |
7de971b0 | 1440 | } |
e60d27c4 PH |
1441 | if (L_ECHO(tty)) { |
1442 | finish_erasing(ldata); | |
1443 | /* Record the column of first canon char. */ | |
1444 | if (ldata->canon_head == ldata->read_head) | |
1445 | echo_set_canon_col(ldata); | |
1446 | echo_char(c, tty); | |
1447 | commit_echoes(tty); | |
1448 | } | |
1449 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1450 | } |
1451 | ||
ad0cc7ba PH |
1452 | static inline void |
1453 | n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) | |
1454 | { | |
1455 | if (I_ISTRIP(tty)) | |
1456 | c &= 0x7f; | |
1457 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1458 | c = tolower(c); | |
1459 | ||
1460 | if (I_IXON(tty)) { | |
1461 | if (c == STOP_CHAR(tty)) | |
1462 | stop_tty(tty); | |
1463 | else if (c == START_CHAR(tty) || | |
1464 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1465 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1466 | c != SUSP_CHAR(tty))) { | |
1467 | start_tty(tty); | |
1468 | process_echoes(tty); | |
1469 | } | |
1470 | } | |
1471 | } | |
1472 | ||
d2f8d7ab PH |
1473 | static void |
1474 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1475 | { | |
1476 | char buf[64]; | |
1477 | ||
1478 | switch (flag) { | |
1479 | case TTY_BREAK: | |
1480 | n_tty_receive_break(tty); | |
1481 | break; | |
1482 | case TTY_PARITY: | |
1483 | case TTY_FRAME: | |
1484 | n_tty_receive_parity_error(tty, c); | |
1485 | break; | |
1486 | case TTY_OVERRUN: | |
1487 | n_tty_receive_overrun(tty); | |
1488 | break; | |
1489 | default: | |
1490 | printk(KERN_ERR "%s: unknown flag %d\n", | |
1491 | tty_name(tty, buf), flag); | |
1492 | break; | |
1493 | } | |
1494 | } | |
1495 | ||
e60d27c4 PH |
1496 | static void |
1497 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1498 | { | |
1499 | struct n_tty_data *ldata = tty->disc_data; | |
1500 | ||
1501 | ldata->lnext = 0; | |
1502 | if (likely(flag == TTY_NORMAL)) { | |
1503 | if (I_ISTRIP(tty)) | |
1504 | c &= 0x7f; | |
1505 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1506 | c = tolower(c); | |
1507 | n_tty_receive_char(tty, c); | |
1508 | } else | |
1509 | n_tty_receive_char_flagged(tty, c, flag); | |
1510 | } | |
1511 | ||
1da177e4 LT |
1512 | /** |
1513 | * n_tty_receive_buf - data receive | |
1514 | * @tty: terminal device | |
1515 | * @cp: buffer | |
1516 | * @fp: flag buffer | |
1517 | * @count: characters | |
1518 | * | |
1519 | * Called by the terminal driver when a block of characters has | |
1520 | * been received. This function must be called from soft contexts | |
1521 | * not from interrupt context. The driver is responsible for making | |
1522 | * calls one at a time and in order (or using flush_to_ldisc) | |
6d76bd26 PH |
1523 | * |
1524 | * n_tty_receive_buf()/producer path: | |
1525 | * claims non-exclusive termios_rwsem | |
1526 | * publishes read_head and canon_head | |
1da177e4 | 1527 | */ |
4edf1827 | 1528 | |
4a23a4df PH |
1529 | static void |
1530 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1531 | char *fp, int count) | |
1532 | { | |
1533 | struct n_tty_data *ldata = tty->disc_data; | |
1534 | size_t n, head; | |
1535 | ||
1536 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1537 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1538 | n = min_t(size_t, count, n); | |
1539 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1540 | ldata->read_head += n; | |
1541 | cp += n; | |
1542 | count -= n; | |
1543 | ||
1544 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1545 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1546 | n = min_t(size_t, count, n); | |
1547 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1548 | ldata->read_head += n; | |
1549 | } | |
1550 | ||
554117bd PH |
1551 | static void |
1552 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1553 | char *fp, int count) | |
1554 | { | |
1555 | struct n_tty_data *ldata = tty->disc_data; | |
1556 | char flag = TTY_NORMAL; | |
1557 | ||
1558 | while (count--) { | |
1559 | if (fp) | |
1560 | flag = *fp++; | |
1561 | if (likely(flag == TTY_NORMAL)) | |
1562 | put_tty_queue(*cp++, ldata); | |
1563 | else | |
1564 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1565 | } | |
1566 | } | |
1567 | ||
ad0cc7ba PH |
1568 | static void |
1569 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1570 | char *fp, int count) | |
1571 | { | |
1572 | char flag = TTY_NORMAL; | |
1573 | ||
1574 | while (count--) { | |
1575 | if (fp) | |
1576 | flag = *fp++; | |
1577 | if (likely(flag == TTY_NORMAL)) | |
1578 | n_tty_receive_char_closing(tty, *cp++); | |
1579 | else | |
1580 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1581 | } | |
1582 | } | |
1583 | ||
7d88d637 PH |
1584 | static void |
1585 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1586 | char *fp, int count) |
1587 | { | |
1588 | struct n_tty_data *ldata = tty->disc_data; | |
1589 | char flag = TTY_NORMAL; | |
1590 | ||
1591 | while (count--) { | |
1592 | if (fp) | |
1593 | flag = *fp++; | |
1594 | if (likely(flag == TTY_NORMAL)) { | |
1595 | unsigned char c = *cp++; | |
1596 | ||
1597 | if (I_ISTRIP(tty)) | |
1598 | c &= 0x7f; | |
1599 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1600 | c = tolower(c); | |
1601 | if (L_EXTPROC(tty)) { | |
1602 | put_tty_queue(c, ldata); | |
1603 | continue; | |
1604 | } | |
e60d27c4 PH |
1605 | if (!test_bit(c, ldata->char_map)) |
1606 | n_tty_receive_char_inline(tty, c); | |
1607 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1608 | if (fp) | |
1609 | flag = *fp++; | |
1610 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1611 | count--; | |
1612 | } | |
6baad008 PH |
1613 | } else |
1614 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1615 | } | |
1616 | } | |
1617 | ||
1618 | static void | |
1619 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1620 | char *fp, int count) | |
7d88d637 | 1621 | { |
e60d27c4 | 1622 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1623 | char flag = TTY_NORMAL; |
1624 | ||
1625 | while (count--) { | |
1626 | if (fp) | |
1627 | flag = *fp++; | |
e60d27c4 PH |
1628 | if (likely(flag == TTY_NORMAL)) { |
1629 | unsigned char c = *cp++; | |
1630 | ||
1631 | if (!test_bit(c, ldata->char_map)) | |
1632 | n_tty_receive_char_fast(tty, c); | |
1633 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1634 | if (fp) | |
1635 | flag = *fp++; | |
1636 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1637 | count--; | |
1638 | } | |
1639 | } else | |
7d88d637 PH |
1640 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1641 | } | |
1642 | } | |
1643 | ||
24a89d1c PH |
1644 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1645 | char *fp, int count) | |
1da177e4 | 1646 | { |
53c5ee2c | 1647 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1648 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1649 | |
4a23a4df PH |
1650 | if (ldata->real_raw) |
1651 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1652 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1653 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1654 | else if (tty->closing && !L_EXTPROC(tty)) |
1655 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1656 | else { |
e60d27c4 PH |
1657 | if (ldata->lnext) { |
1658 | char flag = TTY_NORMAL; | |
1659 | ||
1660 | if (fp) | |
1661 | flag = *fp++; | |
1662 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1663 | count--; | |
1664 | } | |
1665 | ||
7de971b0 | 1666 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1667 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1668 | else | |
1669 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1670 | |
1671 | flush_echoes(tty); | |
f34d7a5b AC |
1672 | if (tty->ops->flush_chars) |
1673 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1674 | } |
1675 | ||
ce74117a | 1676 | if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) || |
26df6d13 | 1677 | L_EXTPROC(tty)) { |
1da177e4 LT |
1678 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1679 | if (waitqueue_active(&tty->read_wait)) | |
1680 | wake_up_interruptible(&tty->read_wait); | |
1681 | } | |
1da177e4 LT |
1682 | } |
1683 | ||
24a89d1c PH |
1684 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1685 | char *fp, int count) | |
1686 | { | |
19e2ad6a PH |
1687 | int room, n; |
1688 | ||
9356b535 | 1689 | down_read(&tty->termios_rwsem); |
19e2ad6a PH |
1690 | |
1691 | while (1) { | |
1692 | room = receive_room(tty); | |
1693 | n = min(count, room); | |
1694 | if (!n) | |
1695 | break; | |
1696 | __receive_buf(tty, cp, fp, n); | |
1697 | cp += n; | |
1698 | if (fp) | |
1699 | fp += n; | |
1700 | count -= n; | |
1701 | } | |
1702 | ||
1703 | tty->receive_room = room; | |
4a23a4df | 1704 | n_tty_check_throttle(tty); |
9356b535 | 1705 | up_read(&tty->termios_rwsem); |
24a89d1c PH |
1706 | } |
1707 | ||
1708 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1709 | char *fp, int count) | |
1710 | { | |
1711 | struct n_tty_data *ldata = tty->disc_data; | |
19e2ad6a | 1712 | int room, n, rcvd = 0; |
24a89d1c | 1713 | |
9356b535 PH |
1714 | down_read(&tty->termios_rwsem); |
1715 | ||
19e2ad6a PH |
1716 | while (1) { |
1717 | room = receive_room(tty); | |
1718 | n = min(count, room); | |
1719 | if (!n) { | |
1720 | if (!room) | |
1721 | ldata->no_room = 1; | |
1722 | break; | |
1723 | } | |
1724 | __receive_buf(tty, cp, fp, n); | |
1725 | cp += n; | |
1726 | if (fp) | |
1727 | fp += n; | |
1728 | count -= n; | |
1729 | rcvd += n; | |
4a23a4df | 1730 | } |
24a89d1c | 1731 | |
19e2ad6a PH |
1732 | tty->receive_room = room; |
1733 | n_tty_check_throttle(tty); | |
9356b535 PH |
1734 | up_read(&tty->termios_rwsem); |
1735 | ||
19e2ad6a | 1736 | return rcvd; |
24a89d1c PH |
1737 | } |
1738 | ||
1da177e4 LT |
1739 | int is_ignored(int sig) |
1740 | { | |
1741 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1742 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1743 | } |
1744 | ||
1745 | /** | |
1746 | * n_tty_set_termios - termios data changed | |
1747 | * @tty: terminal | |
1748 | * @old: previous data | |
1749 | * | |
1750 | * Called by the tty layer when the user changes termios flags so | |
1751 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1752 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1753 | * guaranteed that this function will not be re-entered or in progress |
1754 | * when the ldisc is closed. | |
17b82060 | 1755 | * |
6a1c0680 | 1756 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1757 | */ |
4edf1827 AC |
1758 | |
1759 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1760 | { |
53c5ee2c | 1761 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1762 | |
c786f74e | 1763 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { |
3fe780b3 | 1764 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
93a8d416 | 1765 | ldata->line_start = ldata->canon_head = ldata->read_tail; |
53c5ee2c | 1766 | ldata->erasing = 0; |
6f9b028a | 1767 | ldata->lnext = 0; |
47afa7a5 AC |
1768 | } |
1769 | ||
53c5ee2c | 1770 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1771 | |
1da177e4 LT |
1772 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1773 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1774 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1775 | I_PARMRK(tty)) { | |
1bb9d562 | 1776 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1777 | |
1778 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1779 | set_bit('\r', ldata->char_map); |
1da177e4 | 1780 | if (I_INLCR(tty)) |
1bb9d562 | 1781 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1782 | |
1783 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1784 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1785 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1786 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1787 | set_bit('\n', ldata->char_map); | |
1788 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1789 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1790 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1791 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1792 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1793 | if (L_ECHO(tty)) |
1794 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1795 | ldata->char_map); |
1da177e4 LT |
1796 | } |
1797 | } | |
1798 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1799 | set_bit(START_CHAR(tty), ldata->char_map); |
1800 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1801 | } |
1802 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1803 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1804 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1805 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1806 | } |
1bb9d562 | 1807 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1808 | ldata->raw = 0; |
1809 | ldata->real_raw = 0; | |
1da177e4 | 1810 | } else { |
53c5ee2c | 1811 | ldata->raw = 1; |
1da177e4 LT |
1812 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1813 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1814 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1815 | ldata->real_raw = 1; |
1da177e4 | 1816 | else |
53c5ee2c | 1817 | ldata->real_raw = 0; |
1da177e4 | 1818 | } |
55db4c64 | 1819 | n_tty_set_room(tty); |
dab73b4e WY |
1820 | /* |
1821 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1822 | * been stopped by STOP_CHAR(tty) before it. | |
1823 | */ | |
103fcbe2 | 1824 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) |
dab73b4e | 1825 | start_tty(tty); |
dab73b4e | 1826 | |
f34d7a5b AC |
1827 | /* The termios change make the tty ready for I/O */ |
1828 | wake_up_interruptible(&tty->write_wait); | |
1829 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1830 | } |
1831 | ||
1832 | /** | |
1833 | * n_tty_close - close the ldisc for this tty | |
1834 | * @tty: device | |
1835 | * | |
4edf1827 AC |
1836 | * Called from the terminal layer when this line discipline is |
1837 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1838 | * discipline change. The function will not be called while other |
1839 | * ldisc methods are in progress. | |
1840 | */ | |
4edf1827 | 1841 | |
1da177e4 LT |
1842 | static void n_tty_close(struct tty_struct *tty) |
1843 | { | |
70ece7a7 JS |
1844 | struct n_tty_data *ldata = tty->disc_data; |
1845 | ||
79901317 PH |
1846 | if (tty->link) |
1847 | n_tty_packet_mode_flush(tty); | |
1848 | ||
20bafb3d | 1849 | vfree(ldata); |
70ece7a7 | 1850 | tty->disc_data = NULL; |
1da177e4 LT |
1851 | } |
1852 | ||
1853 | /** | |
1854 | * n_tty_open - open an ldisc | |
1855 | * @tty: terminal to open | |
1856 | * | |
4edf1827 | 1857 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1858 | * terminal device. Can sleep. Called serialized so that no |
1859 | * other events will occur in parallel. No further open will occur | |
1860 | * until a close. | |
1861 | */ | |
1862 | ||
1863 | static int n_tty_open(struct tty_struct *tty) | |
1864 | { | |
70ece7a7 JS |
1865 | struct n_tty_data *ldata; |
1866 | ||
20bafb3d PH |
1867 | /* Currently a malloc failure here can panic */ |
1868 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1869 | if (!ldata) |
1870 | goto err; | |
1871 | ||
53c5ee2c | 1872 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1873 | mutex_init(&ldata->atomic_read_lock); |
1874 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1875 | |
70ece7a7 | 1876 | tty->disc_data = ldata; |
b66f4fa5 | 1877 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1878 | ldata->column = 0; |
20bafb3d | 1879 | ldata->canon_column = 0; |
f6c8dbe6 | 1880 | ldata->minimum_to_wake = 1; |
20bafb3d PH |
1881 | ldata->num_overrun = 0; |
1882 | ldata->no_room = 0; | |
1883 | ldata->lnext = 0; | |
1da177e4 | 1884 | tty->closing = 0; |
b66f4fa5 PH |
1885 | /* indicate buffer work may resume */ |
1886 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1887 | n_tty_set_termios(tty, NULL); | |
1888 | tty_unthrottle(tty); | |
70ece7a7 | 1889 | |
1da177e4 | 1890 | return 0; |
70ece7a7 | 1891 | err: |
b91939f5 | 1892 | return -ENOMEM; |
1da177e4 LT |
1893 | } |
1894 | ||
1895 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1896 | { | |
53c5ee2c JS |
1897 | struct n_tty_data *ldata = tty->disc_data; |
1898 | ||
53c5ee2c | 1899 | if (ldata->icanon && !L_EXTPROC(tty)) { |
a73d3d69 | 1900 | if (ldata->canon_head != ldata->read_tail) |
1da177e4 | 1901 | return 1; |
ce74117a | 1902 | } else if (read_cnt(ldata) >= (amt ? amt : 1)) |
1da177e4 LT |
1903 | return 1; |
1904 | ||
1905 | return 0; | |
1906 | } | |
1907 | ||
1908 | /** | |
bbd20759 | 1909 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1910 | * @tty: terminal device |
1911 | * @b: user data | |
1912 | * @nr: size of data | |
1913 | * | |
11a96d18 | 1914 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1915 | * ICANON is off; it copies characters straight from the tty queue to |
1916 | * user space directly. It can be profitably called twice; once to | |
1917 | * drain the space from the tail pointer to the (physical) end of the | |
1918 | * buffer, and once to drain the space from the (physical) beginning of | |
1919 | * the buffer to head pointer. | |
1920 | * | |
bddc7152 | 1921 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1922 | * |
6d76bd26 PH |
1923 | * n_tty_read()/consumer path: |
1924 | * caller holds non-exclusive termios_rwsem | |
1925 | * read_tail published | |
1da177e4 | 1926 | */ |
4edf1827 | 1927 | |
33f0f88f | 1928 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1929 | unsigned char __user **b, |
1930 | size_t *nr) | |
1931 | ||
1932 | { | |
53c5ee2c | 1933 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1934 | int retval; |
1935 | size_t n; | |
3fa10cc8 | 1936 | bool is_eof; |
bc5a5e3f | 1937 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1938 | |
1939 | retval = 0; | |
bc5a5e3f | 1940 | n = min(read_cnt(ldata), N_TTY_BUF_SIZE - tail); |
1da177e4 | 1941 | n = min(*nr, n); |
1da177e4 | 1942 | if (n) { |
bc5a5e3f | 1943 | retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
1da177e4 | 1944 | n -= retval; |
bc5a5e3f PH |
1945 | is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); |
1946 | tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, | |
53c5ee2c | 1947 | ldata->icanon); |
bc5a5e3f | 1948 | ldata->read_tail += n; |
26df6d13 | 1949 | /* Turn single EOF into zero-length read */ |
ce74117a | 1950 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !read_cnt(ldata)) |
3fa10cc8 | 1951 | n = 0; |
1da177e4 LT |
1952 | *b += n; |
1953 | *nr -= n; | |
1954 | } | |
1955 | return retval; | |
1956 | } | |
1957 | ||
88bb0de3 | 1958 | /** |
32f13521 | 1959 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1960 | * @tty: terminal device |
1961 | * @b: user data | |
1962 | * @nr: size of data | |
1963 | * | |
1964 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1965 | * it copies one line of input up to and including the line-delimiting |
1966 | * character into the user-space buffer. | |
88bb0de3 PH |
1967 | * |
1968 | * Called under the atomic_read_lock mutex | |
6d76bd26 PH |
1969 | * |
1970 | * n_tty_read()/consumer path: | |
1971 | * caller holds non-exclusive termios_rwsem | |
1972 | * read_tail published | |
88bb0de3 PH |
1973 | */ |
1974 | ||
32f13521 PH |
1975 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
1976 | unsigned char __user **b, | |
1977 | size_t *nr) | |
88bb0de3 PH |
1978 | { |
1979 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 1980 | size_t n, size, more, c; |
bc5a5e3f PH |
1981 | size_t eol; |
1982 | size_t tail; | |
1983 | int ret, found = 0; | |
40d5e090 | 1984 | bool eof_push = 0; |
88bb0de3 PH |
1985 | |
1986 | /* N.B. avoid overrun if nr == 0 */ | |
ce74117a | 1987 | n = min(*nr, read_cnt(ldata)); |
6d76bd26 | 1988 | if (!n) |
32f13521 | 1989 | return 0; |
88bb0de3 | 1990 | |
bc5a5e3f | 1991 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
1992 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
1993 | ||
bc5a5e3f | 1994 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
1995 | __func__, *nr, tail, n, size); |
1996 | ||
1997 | eol = find_next_bit(ldata->read_flags, size, tail); | |
1998 | more = n - (size - tail); | |
1999 | if (eol == N_TTY_BUF_SIZE && more) { | |
2000 | /* scan wrapped without finding set bit */ | |
2001 | eol = find_next_bit(ldata->read_flags, more, 0); | |
2002 | if (eol != more) | |
2003 | found = 1; | |
2004 | } else if (eol != size) | |
2005 | found = 1; | |
2006 | ||
2007 | size = N_TTY_BUF_SIZE - tail; | |
c77569d2 PH |
2008 | n = eol - tail; |
2009 | if (n > 4096) | |
2010 | n += 4096; | |
2011 | n += found; | |
32f13521 PH |
2012 | c = n; |
2013 | ||
40d5e090 | 2014 | if (found && read_buf(ldata, eol) == __DISABLED_CHAR) { |
32f13521 | 2015 | n--; |
40d5e090 PH |
2016 | eof_push = !n && ldata->read_tail != ldata->line_start; |
2017 | } | |
32f13521 | 2018 | |
bc5a5e3f | 2019 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", |
32f13521 PH |
2020 | __func__, eol, found, n, c, size, more); |
2021 | ||
32f13521 | 2022 | if (n > size) { |
bc5a5e3f | 2023 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), size); |
32f13521 PH |
2024 | if (ret) |
2025 | return -EFAULT; | |
2026 | ret = copy_to_user(*b + size, ldata->read_buf, n - size); | |
2027 | } else | |
bc5a5e3f | 2028 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
32f13521 PH |
2029 | |
2030 | if (ret) | |
2031 | return -EFAULT; | |
2032 | *b += n; | |
2033 | *nr -= n; | |
2034 | ||
a73d3d69 | 2035 | if (found) |
6d76bd26 PH |
2036 | clear_bit(eol, ldata->read_flags); |
2037 | smp_mb__after_clear_bit(); | |
2038 | ldata->read_tail += c; | |
88bb0de3 | 2039 | |
40d5e090 PH |
2040 | if (found) { |
2041 | ldata->line_start = ldata->read_tail; | |
32f13521 | 2042 | tty_audit_push(tty); |
40d5e090 PH |
2043 | } |
2044 | return eof_push ? -EAGAIN : 0; | |
88bb0de3 PH |
2045 | } |
2046 | ||
cc4191dc | 2047 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2048 | size_t, loff_t *); |
1da177e4 LT |
2049 | |
2050 | /** | |
2051 | * job_control - check job control | |
2052 | * @tty: tty | |
2053 | * @file: file handle | |
2054 | * | |
2055 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2056 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2057 | * error code if action should be taken. |
04f378b1 | 2058 | * |
01a5e440 PH |
2059 | * Locking: redirected write test is safe |
2060 | * current->signal->tty check is safe | |
2061 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2062 | */ |
4edf1827 | 2063 | |
1da177e4 LT |
2064 | static int job_control(struct tty_struct *tty, struct file *file) |
2065 | { | |
2066 | /* Job control check -- must be done at start and after | |
2067 | every sleep (POSIX.1 7.1.1.4). */ | |
2068 | /* NOTE: not yet done after every sleep pending a thorough | |
2069 | check of the logic of this change. -- jlc */ | |
2070 | /* don't stop on /dev/console */ | |
01a5e440 PH |
2071 | if (file->f_op->write == redirected_tty_write || |
2072 | current->signal->tty != tty) | |
2073 | return 0; | |
2074 | ||
2075 | spin_lock_irq(&tty->ctrl_lock); | |
2076 | if (!tty->pgrp) | |
2077 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
2078 | else if (task_pgrp(current) != tty->pgrp) { | |
2079 | spin_unlock_irq(&tty->ctrl_lock); | |
2080 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
2081 | return -EIO; | |
2082 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
2083 | set_thread_flag(TIF_SIGPENDING); | |
2084 | return -ERESTARTSYS; | |
1da177e4 | 2085 | } |
01a5e440 | 2086 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
2087 | return 0; |
2088 | } | |
4edf1827 | 2089 | |
1da177e4 LT |
2090 | |
2091 | /** | |
11a96d18 | 2092 | * n_tty_read - read function for tty |
1da177e4 LT |
2093 | * @tty: tty device |
2094 | * @file: file object | |
2095 | * @buf: userspace buffer pointer | |
2096 | * @nr: size of I/O | |
2097 | * | |
2098 | * Perform reads for the line discipline. We are guaranteed that the | |
2099 | * line discipline will not be closed under us but we may get multiple | |
2100 | * parallel readers and must handle this ourselves. We may also get | |
2101 | * a hangup. Always called in user context, may sleep. | |
2102 | * | |
2103 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2104 | * |
2105 | * n_tty_read()/consumer path: | |
2106 | * claims non-exclusive termios_rwsem | |
2107 | * publishes read_tail | |
1da177e4 | 2108 | */ |
4edf1827 | 2109 | |
11a96d18 | 2110 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2111 | unsigned char __user *buf, size_t nr) |
2112 | { | |
53c5ee2c | 2113 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2114 | unsigned char __user *b = buf; |
2115 | DECLARE_WAITQUEUE(wait, current); | |
2116 | int c; | |
2117 | int minimum, time; | |
2118 | ssize_t retval = 0; | |
1da177e4 LT |
2119 | long timeout; |
2120 | unsigned long flags; | |
04f378b1 | 2121 | int packet; |
1da177e4 | 2122 | |
1da177e4 | 2123 | c = job_control(tty, file); |
4edf1827 | 2124 | if (c < 0) |
1da177e4 | 2125 | return c; |
4edf1827 | 2126 | |
aefceaf4 PH |
2127 | /* |
2128 | * Internal serialization of reads. | |
2129 | */ | |
2130 | if (file->f_flags & O_NONBLOCK) { | |
2131 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2132 | return -EAGAIN; | |
2133 | } else { | |
2134 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2135 | return -ERESTARTSYS; | |
2136 | } | |
2137 | ||
9356b535 PH |
2138 | down_read(&tty->termios_rwsem); |
2139 | ||
1da177e4 LT |
2140 | minimum = time = 0; |
2141 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2142 | if (!ldata->icanon) { |
1da177e4 LT |
2143 | minimum = MIN_CHAR(tty); |
2144 | if (minimum) { | |
a6e54319 | 2145 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2146 | if (time) |
f6c8dbe6 | 2147 | ldata->minimum_to_wake = 1; |
1da177e4 | 2148 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
2149 | (ldata->minimum_to_wake > minimum)) |
2150 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 2151 | } else { |
a6e54319 | 2152 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2153 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2154 | } |
2155 | } | |
2156 | ||
04f378b1 | 2157 | packet = tty->packet; |
1da177e4 LT |
2158 | |
2159 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2160 | while (nr) { |
2161 | /* First test for status change. */ | |
04f378b1 | 2162 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2163 | unsigned char cs; |
2164 | if (b != buf) | |
2165 | break; | |
04f378b1 | 2166 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
2167 | cs = tty->link->ctrl_status; |
2168 | tty->link->ctrl_status = 0; | |
04f378b1 | 2169 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 2170 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2171 | retval = -EFAULT; |
2172 | b--; | |
2173 | break; | |
2174 | } | |
2175 | nr--; | |
2176 | break; | |
2177 | } | |
2178 | /* This statement must be first before checking for input | |
2179 | so that any interrupt will set the state back to | |
2180 | TASK_RUNNING. */ | |
2181 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 2182 | |
f6c8dbe6 | 2183 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2184 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2185 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2186 | |
1da177e4 LT |
2187 | if (!input_available_p(tty, 0)) { |
2188 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
f8747d4a PH |
2189 | up_read(&tty->termios_rwsem); |
2190 | tty_flush_to_ldisc(tty); | |
2191 | down_read(&tty->termios_rwsem); | |
2192 | if (!input_available_p(tty, 0)) { | |
2193 | retval = -EIO; | |
2194 | break; | |
2195 | } | |
2196 | } else { | |
2197 | if (tty_hung_up_p(file)) | |
2198 | break; | |
2199 | if (!timeout) | |
2200 | break; | |
2201 | if (file->f_flags & O_NONBLOCK) { | |
2202 | retval = -EAGAIN; | |
2203 | break; | |
2204 | } | |
2205 | if (signal_pending(current)) { | |
2206 | retval = -ERESTARTSYS; | |
2207 | break; | |
2208 | } | |
2209 | n_tty_set_room(tty); | |
2210 | up_read(&tty->termios_rwsem); | |
9356b535 | 2211 | |
f8747d4a | 2212 | timeout = schedule_timeout(timeout); |
9356b535 | 2213 | |
f8747d4a PH |
2214 | down_read(&tty->termios_rwsem); |
2215 | continue; | |
2216 | } | |
1da177e4 LT |
2217 | } |
2218 | __set_current_state(TASK_RUNNING); | |
2219 | ||
2220 | /* Deal with packet mode. */ | |
04f378b1 | 2221 | if (packet && b == buf) { |
522ed776 | 2222 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
2223 | retval = -EFAULT; |
2224 | b--; | |
2225 | break; | |
2226 | } | |
2227 | nr--; | |
2228 | } | |
2229 | ||
53c5ee2c | 2230 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2231 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
40d5e090 PH |
2232 | if (retval == -EAGAIN) { |
2233 | retval = 0; | |
2234 | continue; | |
2235 | } else if (retval) | |
1da177e4 LT |
2236 | break; |
2237 | } else { | |
2238 | int uncopied; | |
04f378b1 AC |
2239 | /* The copy function takes the read lock and handles |
2240 | locking internally for this case */ | |
1da177e4 LT |
2241 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2242 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2243 | if (uncopied) { | |
2244 | retval = -EFAULT; | |
2245 | break; | |
2246 | } | |
2247 | } | |
2248 | ||
6367ca72 | 2249 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2250 | |
2251 | if (b - buf >= minimum) | |
2252 | break; | |
2253 | if (time) | |
2254 | timeout = time; | |
2255 | } | |
42458f41 PH |
2256 | n_tty_set_room(tty); |
2257 | up_read(&tty->termios_rwsem); | |
2258 | ||
1da177e4 | 2259 | remove_wait_queue(&tty->read_wait, &wait); |
1da177e4 | 2260 | if (!waitqueue_active(&tty->read_wait)) |
f6c8dbe6 | 2261 | ldata->minimum_to_wake = minimum; |
1da177e4 | 2262 | |
aebf0453 PH |
2263 | mutex_unlock(&ldata->atomic_read_lock); |
2264 | ||
1da177e4 | 2265 | __set_current_state(TASK_RUNNING); |
40d5e090 PH |
2266 | if (b - buf) |
2267 | retval = b - buf; | |
1da177e4 LT |
2268 | |
2269 | return retval; | |
2270 | } | |
2271 | ||
2272 | /** | |
11a96d18 | 2273 | * n_tty_write - write function for tty |
1da177e4 LT |
2274 | * @tty: tty device |
2275 | * @file: file object | |
2276 | * @buf: userspace buffer pointer | |
2277 | * @nr: size of I/O | |
2278 | * | |
a88a69c9 | 2279 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2280 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2281 | * and other such events. Since the receive code will echo characters, |
2282 | * thus calling driver write methods, the output_lock is used in | |
2283 | * the output processing functions called here as well as in the | |
2284 | * echo processing function to protect the column state and space | |
2285 | * left in the buffer. | |
1da177e4 LT |
2286 | * |
2287 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2288 | * |
2289 | * Locking: output_lock to protect column state and space left | |
2290 | * (note that the process_output*() functions take this | |
2291 | * lock themselves) | |
1da177e4 | 2292 | */ |
4edf1827 | 2293 | |
11a96d18 | 2294 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2295 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2296 | { |
2297 | const unsigned char *b = buf; | |
2298 | DECLARE_WAITQUEUE(wait, current); | |
2299 | int c; | |
2300 | ssize_t retval = 0; | |
2301 | ||
2302 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2303 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2304 | retval = tty_check_change(tty); | |
2305 | if (retval) | |
2306 | return retval; | |
2307 | } | |
2308 | ||
9356b535 PH |
2309 | down_read(&tty->termios_rwsem); |
2310 | ||
a88a69c9 JP |
2311 | /* Write out any echoed characters that are still pending */ |
2312 | process_echoes(tty); | |
300a6204 | 2313 | |
1da177e4 LT |
2314 | add_wait_queue(&tty->write_wait, &wait); |
2315 | while (1) { | |
2316 | set_current_state(TASK_INTERRUPTIBLE); | |
2317 | if (signal_pending(current)) { | |
2318 | retval = -ERESTARTSYS; | |
2319 | break; | |
2320 | } | |
2321 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2322 | retval = -EIO; | |
2323 | break; | |
2324 | } | |
582f5590 | 2325 | if (O_OPOST(tty)) { |
1da177e4 | 2326 | while (nr > 0) { |
a88a69c9 | 2327 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2328 | if (num < 0) { |
2329 | if (num == -EAGAIN) | |
2330 | break; | |
2331 | retval = num; | |
2332 | goto break_out; | |
2333 | } | |
2334 | b += num; | |
2335 | nr -= num; | |
2336 | if (nr == 0) | |
2337 | break; | |
2338 | c = *b; | |
a88a69c9 | 2339 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2340 | break; |
2341 | b++; nr--; | |
2342 | } | |
f34d7a5b AC |
2343 | if (tty->ops->flush_chars) |
2344 | tty->ops->flush_chars(tty); | |
1da177e4 | 2345 | } else { |
d6afe27b | 2346 | while (nr > 0) { |
f34d7a5b | 2347 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
2348 | if (c < 0) { |
2349 | retval = c; | |
2350 | goto break_out; | |
2351 | } | |
2352 | if (!c) | |
2353 | break; | |
2354 | b += c; | |
2355 | nr -= c; | |
1da177e4 | 2356 | } |
1da177e4 LT |
2357 | } |
2358 | if (!nr) | |
2359 | break; | |
2360 | if (file->f_flags & O_NONBLOCK) { | |
2361 | retval = -EAGAIN; | |
2362 | break; | |
2363 | } | |
9356b535 PH |
2364 | up_read(&tty->termios_rwsem); |
2365 | ||
1da177e4 | 2366 | schedule(); |
9356b535 PH |
2367 | |
2368 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2369 | } |
2370 | break_out: | |
2371 | __set_current_state(TASK_RUNNING); | |
2372 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2373 | if (b - buf != nr && tty->fasync) |
2374 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2375 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2376 | return (b - buf) ? b - buf : retval; |
2377 | } | |
2378 | ||
2379 | /** | |
11a96d18 | 2380 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2381 | * @tty: terminal device |
2382 | * @file: file accessing it | |
2383 | * @wait: poll table | |
2384 | * | |
2385 | * Called when the line discipline is asked to poll() for data or | |
2386 | * for special events. This code is not serialized with respect to | |
2387 | * other events save open/close. | |
2388 | * | |
2389 | * This code must be sure never to sleep through a hangup. | |
2390 | * Called without the kernel lock held - fine | |
1da177e4 | 2391 | */ |
4edf1827 | 2392 | |
11a96d18 | 2393 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2394 | poll_table *wait) |
1da177e4 | 2395 | { |
f6c8dbe6 | 2396 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2397 | unsigned int mask = 0; |
2398 | ||
2399 | poll_wait(file, &tty->read_wait, wait); | |
2400 | poll_wait(file, &tty->write_wait, wait); | |
2401 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2402 | mask |= POLLIN | POLLRDNORM; | |
2403 | if (tty->packet && tty->link->ctrl_status) | |
2404 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2405 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2406 | mask |= POLLHUP; | |
2407 | if (tty_hung_up_p(file)) | |
2408 | mask |= POLLHUP; | |
2409 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2410 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2411 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2412 | else |
f6c8dbe6 | 2413 | ldata->minimum_to_wake = 1; |
1da177e4 | 2414 | } |
f34d7a5b AC |
2415 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2416 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2417 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2418 | mask |= POLLOUT | POLLWRNORM; |
2419 | return mask; | |
2420 | } | |
2421 | ||
57c94121 | 2422 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2423 | { |
bc5a5e3f | 2424 | size_t nr, head, tail; |
47afa7a5 | 2425 | |
a73d3d69 | 2426 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2427 | return 0; |
ba2e68ac JS |
2428 | head = ldata->canon_head; |
2429 | tail = ldata->read_tail; | |
bc5a5e3f | 2430 | nr = head - tail; |
47afa7a5 AC |
2431 | /* Skip EOF-chars.. */ |
2432 | while (head != tail) { | |
bc5a5e3f PH |
2433 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2434 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2435 | nr--; |
bc5a5e3f | 2436 | tail++; |
47afa7a5 AC |
2437 | } |
2438 | return nr; | |
2439 | } | |
2440 | ||
2441 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2442 | unsigned int cmd, unsigned long arg) | |
2443 | { | |
ba2e68ac | 2444 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2445 | int retval; |
2446 | ||
2447 | switch (cmd) { | |
2448 | case TIOCOUTQ: | |
2449 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2450 | case TIOCINQ: | |
6d76bd26 | 2451 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2452 | if (L_ICANON(tty)) |
57c94121 | 2453 | retval = inq_canon(ldata); |
6d76bd26 PH |
2454 | else |
2455 | retval = read_cnt(ldata); | |
2456 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2457 | return put_user(retval, (unsigned int __user *) arg); |
2458 | default: | |
2459 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2460 | } | |
2461 | } | |
2462 | ||
f6c8dbe6 PH |
2463 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2464 | { | |
2465 | struct n_tty_data *ldata = tty->disc_data; | |
2466 | ||
2467 | if (!waitqueue_active(&tty->read_wait)) { | |
2468 | if (on) | |
2469 | ldata->minimum_to_wake = 1; | |
2470 | else if (!tty->fasync) | |
2471 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2472 | } | |
2473 | } | |
2474 | ||
a352def2 | 2475 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2476 | .magic = TTY_LDISC_MAGIC, |
2477 | .name = "n_tty", | |
2478 | .open = n_tty_open, | |
2479 | .close = n_tty_close, | |
2480 | .flush_buffer = n_tty_flush_buffer, | |
2481 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2482 | .read = n_tty_read, |
2483 | .write = n_tty_write, | |
e10cc1df PF |
2484 | .ioctl = n_tty_ioctl, |
2485 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2486 | .poll = n_tty_poll, |
e10cc1df | 2487 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2488 | .write_wakeup = n_tty_write_wakeup, |
2489 | .fasync = n_tty_fasync, | |
24a89d1c | 2490 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2491 | }; |
572b9adb RG |
2492 | |
2493 | /** | |
2494 | * n_tty_inherit_ops - inherit N_TTY methods | |
2495 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2496 | * | |
593fb1ae | 2497 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2498 | * methods. |
2499 | */ | |
2500 | ||
2501 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2502 | { | |
2503 | *ops = tty_ldisc_N_TTY; | |
2504 | ops->owner = NULL; | |
2505 | ops->refcount = ops->flags = 0; | |
2506 | } | |
2507 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |