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; |
4d0ed182 | 108 | unsigned char push:1; |
3fe780b3 | 109 | |
fb7aa03d | 110 | /* shared by producer and consumer */ |
20bafb3d | 111 | char read_buf[N_TTY_BUF_SIZE]; |
3fe780b3 | 112 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
20bafb3d | 113 | unsigned char echo_buf[N_TTY_BUF_SIZE]; |
ba2e68ac | 114 | |
f6c8dbe6 | 115 | int minimum_to_wake; |
ba2e68ac | 116 | |
fb7aa03d PH |
117 | /* consumer-published */ |
118 | size_t read_tail; | |
40d5e090 | 119 | size_t line_start; |
fb7aa03d | 120 | |
fb7aa03d PH |
121 | /* protected by output lock */ |
122 | unsigned int column; | |
ba2e68ac | 123 | unsigned int canon_column; |
9dfd16dd | 124 | size_t echo_tail; |
bddc7152 JS |
125 | |
126 | struct mutex atomic_read_lock; | |
127 | struct mutex output_lock; | |
70ece7a7 JS |
128 | }; |
129 | ||
ce74117a PH |
130 | static inline size_t read_cnt(struct n_tty_data *ldata) |
131 | { | |
a2f73be8 | 132 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
133 | } |
134 | ||
bc5a5e3f PH |
135 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
136 | { | |
137 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
138 | } | |
139 | ||
140 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
141 | { | |
142 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
143 | } | |
144 | ||
addaebcc PH |
145 | static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) |
146 | { | |
147 | return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
148 | } | |
149 | ||
150 | static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) | |
151 | { | |
152 | return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
153 | } | |
154 | ||
522ed776 MT |
155 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
156 | unsigned char __user *ptr) | |
157 | { | |
53c5ee2c JS |
158 | struct n_tty_data *ldata = tty->disc_data; |
159 | ||
160 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
161 | return put_user(x, ptr); |
162 | } | |
163 | ||
24a89d1c | 164 | static int receive_room(struct tty_struct *tty) |
55db4c64 | 165 | { |
53c5ee2c | 166 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 167 | int left; |
55db4c64 | 168 | |
090abf7b JA |
169 | if (I_PARMRK(tty)) { |
170 | /* Multiply read_cnt by 3, since each byte might take up to | |
171 | * three times as many spaces when PARMRK is set (depending on | |
172 | * its flags, e.g. parity error). */ | |
ce74117a | 173 | left = N_TTY_BUF_SIZE - read_cnt(ldata) * 3 - 1; |
090abf7b | 174 | } else |
ce74117a | 175 | left = N_TTY_BUF_SIZE - read_cnt(ldata) - 1; |
090abf7b | 176 | |
55db4c64 LT |
177 | /* |
178 | * If we are doing input canonicalization, and there are no | |
179 | * pending newlines, let characters through without limit, so | |
180 | * that erase characters will be handled. Other excess | |
181 | * characters will be beeped. | |
182 | */ | |
183 | if (left <= 0) | |
a73d3d69 | 184 | left = ldata->icanon && ldata->canon_head == ldata->read_tail; |
55db4c64 | 185 | |
24a89d1c | 186 | return left; |
7879a9f9 PH |
187 | } |
188 | ||
24a89d1c PH |
189 | /** |
190 | * n_tty_set_room - receive space | |
191 | * @tty: terminal | |
192 | * | |
193 | * Re-schedules the flip buffer work if space just became available. | |
194 | * | |
6d76bd26 PH |
195 | * Caller holds exclusive termios_rwsem |
196 | * or | |
197 | * n_tty_read()/consumer path: | |
198 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
199 | */ |
200 | ||
7879a9f9 PH |
201 | static void n_tty_set_room(struct tty_struct *tty) |
202 | { | |
24a89d1c PH |
203 | struct n_tty_data *ldata = tty->disc_data; |
204 | ||
55db4c64 | 205 | /* Did this open up the receive buffer? We may need to flip */ |
24a89d1c PH |
206 | if (unlikely(ldata->no_room) && receive_room(tty)) { |
207 | ldata->no_room = 0; | |
208 | ||
ecbbfd44 | 209 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 210 | "scheduling with invalid itty\n"); |
21622939 PH |
211 | /* see if ldisc has been killed - if so, this means that |
212 | * even though the ldisc has been halted and ->buf.work | |
213 | * cancelled, ->buf.work is about to be rescheduled | |
214 | */ | |
215 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
216 | "scheduling buffer work for halted ldisc\n"); | |
f0f947c1 | 217 | queue_work(system_unbound_wq, &tty->port->buf.work); |
ecbbfd44 | 218 | } |
55db4c64 LT |
219 | } |
220 | ||
9a4aec2d PH |
221 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
222 | { | |
223 | struct n_tty_data *ldata = tty->disc_data; | |
224 | ssize_t n = 0; | |
225 | ||
226 | if (!ldata->icanon) | |
227 | n = read_cnt(ldata); | |
228 | else | |
229 | n = ldata->canon_head - ldata->read_tail; | |
230 | return n; | |
231 | } | |
232 | ||
ee0bab83 PH |
233 | /** |
234 | * n_tty_write_wakeup - asynchronous I/O notifier | |
235 | * @tty: tty device | |
236 | * | |
237 | * Required for the ptys, serial driver etc. since processes | |
238 | * that attach themselves to the master and rely on ASYNC | |
239 | * IO must be woken up | |
240 | */ | |
241 | ||
242 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
243 | { | |
244 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) | |
245 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
246 | } | |
247 | ||
4a23a4df | 248 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 249 | { |
3afb1b39 PH |
250 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) |
251 | return; | |
6367ca72 PH |
252 | /* |
253 | * Check the remaining room for the input canonicalization | |
254 | * mode. We don't want to throttle the driver if we're in | |
255 | * canonical mode and don't have a newline yet! | |
256 | */ | |
257 | while (1) { | |
258 | int throttled; | |
259 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
260 | if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) | |
261 | break; | |
262 | throttled = tty_throttle_safe(tty); | |
263 | if (!throttled) | |
264 | break; | |
265 | } | |
266 | __tty_set_flow_change(tty, 0); | |
267 | } | |
268 | ||
4b293492 | 269 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 270 | { |
3afb1b39 PH |
271 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
272 | tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { | |
273 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
274 | return; | |
275 | if (!tty->count) | |
276 | return; | |
277 | n_tty_set_room(tty); | |
278 | n_tty_write_wakeup(tty->link); | |
6c67716d PH |
279 | if (waitqueue_active(&tty->link->write_wait)) |
280 | wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); | |
3afb1b39 PH |
281 | return; |
282 | } | |
283 | ||
6367ca72 PH |
284 | /* If there is enough space in the read buffer now, let the |
285 | * low-level driver know. We use chars_in_buffer() to | |
286 | * check the buffer, as it now knows about canonical mode. | |
287 | * Otherwise, if the driver is throttled and the line is | |
288 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
289 | * we won't get any more characters. | |
290 | */ | |
291 | ||
292 | while (1) { | |
293 | int unthrottled; | |
294 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
295 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
296 | break; | |
297 | if (!tty->count) | |
298 | break; | |
299 | n_tty_set_room(tty); | |
300 | unthrottled = tty_unthrottle_safe(tty); | |
301 | if (!unthrottled) | |
302 | break; | |
303 | } | |
304 | __tty_set_flow_change(tty, 0); | |
305 | } | |
306 | ||
17b82060 AC |
307 | /** |
308 | * put_tty_queue - add character to tty | |
309 | * @c: character | |
57c94121 | 310 | * @ldata: n_tty data |
17b82060 | 311 | * |
6d76bd26 PH |
312 | * Add a character to the tty read_buf queue. |
313 | * | |
314 | * n_tty_receive_buf()/producer path: | |
315 | * caller holds non-exclusive termios_rwsem | |
316 | * modifies read_head | |
317 | * | |
318 | * read_head is only considered 'published' if canonical mode is | |
319 | * not active. | |
17b82060 AC |
320 | */ |
321 | ||
19e2ad6a | 322 | static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 323 | { |
19e2ad6a | 324 | *read_buf_addr(ldata, ldata->read_head++) = c; |
1da177e4 LT |
325 | } |
326 | ||
1da177e4 LT |
327 | /** |
328 | * reset_buffer_flags - reset buffer state | |
329 | * @tty: terminal to reset | |
330 | * | |
25518c68 PH |
331 | * Reset the read buffer counters and clear the flags. |
332 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 333 | * |
6d76bd26 PH |
334 | * Locking: caller holds exclusive termios_rwsem |
335 | * (or locking is not required) | |
1da177e4 | 336 | */ |
a88a69c9 | 337 | |
b66f4fa5 | 338 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 339 | { |
a73d3d69 | 340 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 341 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
1075a6e2 | 342 | ldata->echo_mark = 0; |
40d5e090 | 343 | ldata->line_start = 0; |
a88a69c9 | 344 | |
a73d3d69 | 345 | ldata->erasing = 0; |
3fe780b3 | 346 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 | 347 | ldata->push = 0; |
1da177e4 LT |
348 | } |
349 | ||
a30737ab PH |
350 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
351 | { | |
352 | unsigned long flags; | |
353 | ||
354 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
355 | if (tty->link->packet) { | |
356 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
6c67716d PH |
357 | if (waitqueue_active(&tty->link->read_wait)) |
358 | wake_up_interruptible(&tty->link->read_wait); | |
a30737ab PH |
359 | } |
360 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
361 | } | |
362 | ||
1da177e4 LT |
363 | /** |
364 | * n_tty_flush_buffer - clean input queue | |
365 | * @tty: terminal device | |
366 | * | |
25518c68 PH |
367 | * Flush the input buffer. Called when the tty layer wants the |
368 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
369 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 370 | * |
6d76bd26 PH |
371 | * Holds termios_rwsem to exclude producer/consumer while |
372 | * buffer indices are reset. | |
373 | * | |
374 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 375 | */ |
4edf1827 AC |
376 | |
377 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 378 | { |
6d76bd26 | 379 | down_write(&tty->termios_rwsem); |
b66f4fa5 PH |
380 | reset_buffer_flags(tty->disc_data); |
381 | n_tty_set_room(tty); | |
4edf1827 | 382 | |
a30737ab PH |
383 | if (tty->link) |
384 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 385 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
386 | } |
387 | ||
6d76bd26 PH |
388 | /** |
389 | * n_tty_chars_in_buffer - report available bytes | |
390 | * @tty: tty device | |
391 | * | |
392 | * Report the number of characters buffered to be delivered to user | |
393 | * at this instant in time. | |
394 | * | |
395 | * Locking: exclusive termios_rwsem | |
396 | */ | |
397 | ||
a19d0c6a PH |
398 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
399 | { | |
6d76bd26 PH |
400 | ssize_t n; |
401 | ||
47534084 | 402 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
6d76bd26 PH |
403 | |
404 | down_write(&tty->termios_rwsem); | |
405 | n = chars_in_buffer(tty); | |
406 | up_write(&tty->termios_rwsem); | |
407 | return n; | |
a19d0c6a PH |
408 | } |
409 | ||
1da177e4 LT |
410 | /** |
411 | * is_utf8_continuation - utf8 multibyte check | |
412 | * @c: byte to check | |
413 | * | |
414 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
415 | * character. We use this to correctly compute the on screen size | |
416 | * of the character when printing | |
417 | */ | |
4edf1827 | 418 | |
1da177e4 LT |
419 | static inline int is_utf8_continuation(unsigned char c) |
420 | { | |
421 | return (c & 0xc0) == 0x80; | |
422 | } | |
423 | ||
424 | /** | |
425 | * is_continuation - multibyte check | |
426 | * @c: byte to check | |
427 | * | |
428 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
429 | * character and the terminal is in unicode mode. | |
430 | */ | |
4edf1827 | 431 | |
1da177e4 LT |
432 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
433 | { | |
434 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
435 | } | |
436 | ||
437 | /** | |
a88a69c9 | 438 | * do_output_char - output one character |
1da177e4 LT |
439 | * @c: character (or partial unicode symbol) |
440 | * @tty: terminal device | |
a88a69c9 | 441 | * @space: space available in tty driver write buffer |
1da177e4 | 442 | * |
a88a69c9 JP |
443 | * This is a helper function that handles one output character |
444 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
445 | * doing OPOST processing and putting the results in the |
446 | * tty driver's write buffer. | |
a88a69c9 JP |
447 | * |
448 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
449 | * and NLDLY. They simply aren't relevant in the world today. | |
450 | * If you ever need them, add them here. | |
1da177e4 | 451 | * |
a88a69c9 JP |
452 | * Returns the number of bytes of buffer space used or -1 if |
453 | * no space left. | |
454 | * | |
455 | * Locking: should be called under the output_lock to protect | |
456 | * the column state and space left in the buffer | |
1da177e4 | 457 | */ |
4edf1827 | 458 | |
a88a69c9 | 459 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 460 | { |
53c5ee2c | 461 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 462 | int spaces; |
1da177e4 | 463 | |
1da177e4 LT |
464 | if (!space) |
465 | return -1; | |
300a6204 | 466 | |
a88a69c9 JP |
467 | switch (c) { |
468 | case '\n': | |
469 | if (O_ONLRET(tty)) | |
53c5ee2c | 470 | ldata->column = 0; |
a88a69c9 JP |
471 | if (O_ONLCR(tty)) { |
472 | if (space < 2) | |
473 | return -1; | |
ba2e68ac | 474 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 475 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
476 | return 2; |
477 | } | |
ba2e68ac | 478 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
479 | break; |
480 | case '\r': | |
53c5ee2c | 481 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
482 | return 0; |
483 | if (O_OCRNL(tty)) { | |
484 | c = '\n'; | |
485 | if (O_ONLRET(tty)) | |
ba2e68ac | 486 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 487 | break; |
a88a69c9 | 488 | } |
ba2e68ac | 489 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
490 | break; |
491 | case '\t': | |
53c5ee2c | 492 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
493 | if (O_TABDLY(tty) == XTABS) { |
494 | if (space < spaces) | |
495 | return -1; | |
53c5ee2c | 496 | ldata->column += spaces; |
a88a69c9 JP |
497 | tty->ops->write(tty, " ", spaces); |
498 | return spaces; | |
1da177e4 | 499 | } |
53c5ee2c | 500 | ldata->column += spaces; |
a88a69c9 JP |
501 | break; |
502 | case '\b': | |
53c5ee2c JS |
503 | if (ldata->column > 0) |
504 | ldata->column--; | |
a88a69c9 JP |
505 | break; |
506 | default: | |
a59c0d6f JP |
507 | if (!iscntrl(c)) { |
508 | if (O_OLCUC(tty)) | |
509 | c = toupper(c); | |
510 | if (!is_continuation(c, tty)) | |
53c5ee2c | 511 | ldata->column++; |
a59c0d6f | 512 | } |
a88a69c9 | 513 | break; |
1da177e4 | 514 | } |
a88a69c9 | 515 | |
f34d7a5b | 516 | tty_put_char(tty, c); |
a88a69c9 JP |
517 | return 1; |
518 | } | |
519 | ||
520 | /** | |
521 | * process_output - output post processor | |
522 | * @c: character (or partial unicode symbol) | |
523 | * @tty: terminal device | |
524 | * | |
ee5aa7b8 JP |
525 | * Output one character with OPOST processing. |
526 | * Returns -1 when the output device is full and the character | |
527 | * must be retried. | |
a88a69c9 JP |
528 | * |
529 | * Locking: output_lock to protect column state and space left | |
530 | * (also, this is called from n_tty_write under the | |
531 | * tty layer write lock) | |
532 | */ | |
533 | ||
534 | static int process_output(unsigned char c, struct tty_struct *tty) | |
535 | { | |
bddc7152 | 536 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
537 | int space, retval; |
538 | ||
bddc7152 | 539 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
540 | |
541 | space = tty_write_room(tty); | |
542 | retval = do_output_char(c, tty, space); | |
543 | ||
bddc7152 | 544 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
545 | if (retval < 0) |
546 | return -1; | |
547 | else | |
548 | return 0; | |
1da177e4 LT |
549 | } |
550 | ||
551 | /** | |
a88a69c9 | 552 | * process_output_block - block post processor |
1da177e4 | 553 | * @tty: terminal device |
ee5aa7b8 JP |
554 | * @buf: character buffer |
555 | * @nr: number of bytes to output | |
556 | * | |
557 | * Output a block of characters with OPOST processing. | |
558 | * Returns the number of characters output. | |
1da177e4 LT |
559 | * |
560 | * This path is used to speed up block console writes, among other | |
561 | * things when processing blocks of output data. It handles only | |
562 | * the simple cases normally found and helps to generate blocks of | |
563 | * symbols for the console driver and thus improve performance. | |
564 | * | |
a88a69c9 JP |
565 | * Locking: output_lock to protect column state and space left |
566 | * (also, this is called from n_tty_write under the | |
567 | * tty layer write lock) | |
1da177e4 | 568 | */ |
4edf1827 | 569 | |
a88a69c9 JP |
570 | static ssize_t process_output_block(struct tty_struct *tty, |
571 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 572 | { |
53c5ee2c | 573 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 574 | int space; |
bbd20759 | 575 | int i; |
1da177e4 LT |
576 | const unsigned char *cp; |
577 | ||
bddc7152 | 578 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 579 | |
f34d7a5b | 580 | space = tty_write_room(tty); |
300a6204 | 581 | if (!space) { |
bddc7152 | 582 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 583 | return 0; |
a88a69c9 | 584 | } |
1da177e4 LT |
585 | if (nr > space) |
586 | nr = space; | |
587 | ||
588 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
589 | unsigned char c = *cp; |
590 | ||
591 | switch (c) { | |
1da177e4 LT |
592 | case '\n': |
593 | if (O_ONLRET(tty)) | |
53c5ee2c | 594 | ldata->column = 0; |
1da177e4 LT |
595 | if (O_ONLCR(tty)) |
596 | goto break_out; | |
ba2e68ac | 597 | ldata->canon_column = ldata->column; |
1da177e4 LT |
598 | break; |
599 | case '\r': | |
53c5ee2c | 600 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
601 | goto break_out; |
602 | if (O_OCRNL(tty)) | |
603 | goto break_out; | |
ba2e68ac | 604 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
605 | break; |
606 | case '\t': | |
607 | goto break_out; | |
608 | case '\b': | |
53c5ee2c JS |
609 | if (ldata->column > 0) |
610 | ldata->column--; | |
1da177e4 LT |
611 | break; |
612 | default: | |
a59c0d6f JP |
613 | if (!iscntrl(c)) { |
614 | if (O_OLCUC(tty)) | |
615 | goto break_out; | |
616 | if (!is_continuation(c, tty)) | |
53c5ee2c | 617 | ldata->column++; |
a59c0d6f | 618 | } |
1da177e4 LT |
619 | break; |
620 | } | |
621 | } | |
622 | break_out: | |
f34d7a5b | 623 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 624 | |
bddc7152 | 625 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
626 | return i; |
627 | } | |
628 | ||
a88a69c9 JP |
629 | /** |
630 | * process_echoes - write pending echo characters | |
631 | * @tty: terminal device | |
632 | * | |
633 | * Write previously buffered echo (and other ldisc-generated) | |
634 | * characters to the tty. | |
635 | * | |
636 | * Characters generated by the ldisc (including echoes) need to | |
637 | * be buffered because the driver's write buffer can fill during | |
638 | * heavy program output. Echoing straight to the driver will | |
639 | * often fail under these conditions, causing lost characters and | |
640 | * resulting mismatches of ldisc state information. | |
641 | * | |
642 | * Since the ldisc state must represent the characters actually sent | |
643 | * to the driver at the time of the write, operations like certain | |
644 | * changes in column state are also saved in the buffer and executed | |
645 | * here. | |
646 | * | |
647 | * A circular fifo buffer is used so that the most recent characters | |
648 | * are prioritized. Also, when control characters are echoed with a | |
649 | * prefixed "^", the pair is treated atomically and thus not separated. | |
650 | * | |
019ebdf9 | 651 | * Locking: callers must hold output_lock |
a88a69c9 JP |
652 | */ |
653 | ||
bc5b1ec5 | 654 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 655 | { |
53c5ee2c | 656 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 657 | int space, old_space; |
addaebcc | 658 | size_t tail; |
a88a69c9 | 659 | unsigned char c; |
a88a69c9 | 660 | |
bc5b1ec5 | 661 | old_space = space = tty_write_room(tty); |
a88a69c9 | 662 | |
addaebcc | 663 | tail = ldata->echo_tail; |
29c7c5ca | 664 | while (ldata->echo_commit != tail) { |
addaebcc | 665 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
666 | if (c == ECHO_OP_START) { |
667 | unsigned char op; | |
a88a69c9 JP |
668 | int no_space_left = 0; |
669 | ||
670 | /* | |
671 | * If the buffer byte is the start of a multi-byte | |
672 | * operation, get the next byte, which is either the | |
673 | * op code or a control character value. | |
674 | */ | |
addaebcc | 675 | op = echo_buf(ldata, tail + 1); |
300a6204 | 676 | |
a88a69c9 JP |
677 | switch (op) { |
678 | unsigned int num_chars, num_bs; | |
679 | ||
680 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 681 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
682 | |
683 | /* | |
684 | * Determine how many columns to go back | |
685 | * in order to erase the tab. | |
686 | * This depends on the number of columns | |
687 | * used by other characters within the tab | |
688 | * area. If this (modulo 8) count is from | |
689 | * the start of input rather than from a | |
690 | * previous tab, we offset by canon column. | |
691 | * Otherwise, tab spacing is normal. | |
692 | */ | |
693 | if (!(num_chars & 0x80)) | |
ba2e68ac | 694 | num_chars += ldata->canon_column; |
a88a69c9 JP |
695 | num_bs = 8 - (num_chars & 7); |
696 | ||
697 | if (num_bs > space) { | |
698 | no_space_left = 1; | |
699 | break; | |
700 | } | |
701 | space -= num_bs; | |
702 | while (num_bs--) { | |
703 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
704 | if (ldata->column > 0) |
705 | ldata->column--; | |
a88a69c9 | 706 | } |
addaebcc | 707 | tail += 3; |
a88a69c9 JP |
708 | break; |
709 | ||
710 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 711 | ldata->canon_column = ldata->column; |
addaebcc | 712 | tail += 2; |
a88a69c9 JP |
713 | break; |
714 | ||
715 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
716 | if (ldata->column > 0) |
717 | ldata->column--; | |
addaebcc | 718 | tail += 2; |
a88a69c9 JP |
719 | break; |
720 | ||
721 | case ECHO_OP_START: | |
722 | /* This is an escaped echo op start code */ | |
723 | if (!space) { | |
724 | no_space_left = 1; | |
725 | break; | |
726 | } | |
727 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 728 | ldata->column++; |
a88a69c9 | 729 | space--; |
addaebcc | 730 | tail += 2; |
a88a69c9 JP |
731 | break; |
732 | ||
733 | default: | |
a88a69c9 | 734 | /* |
62b26358 JP |
735 | * If the op is not a special byte code, |
736 | * it is a ctrl char tagged to be echoed | |
737 | * as "^X" (where X is the letter | |
738 | * representing the control char). | |
739 | * Note that we must ensure there is | |
740 | * enough space for the whole ctrl pair. | |
741 | * | |
a88a69c9 | 742 | */ |
62b26358 JP |
743 | if (space < 2) { |
744 | no_space_left = 1; | |
745 | break; | |
746 | } | |
747 | tty_put_char(tty, '^'); | |
748 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 749 | ldata->column += 2; |
62b26358 | 750 | space -= 2; |
addaebcc | 751 | tail += 2; |
a88a69c9 JP |
752 | } |
753 | ||
754 | if (no_space_left) | |
755 | break; | |
756 | } else { | |
582f5590 | 757 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
758 | int retval = do_output_char(c, tty, space); |
759 | if (retval < 0) | |
760 | break; | |
761 | space -= retval; | |
762 | } else { | |
763 | if (!space) | |
764 | break; | |
765 | tty_put_char(tty, c); | |
766 | space -= 1; | |
767 | } | |
addaebcc | 768 | tail += 1; |
a88a69c9 | 769 | } |
a88a69c9 JP |
770 | } |
771 | ||
cbfd0340 PH |
772 | /* If the echo buffer is nearly full (so that the possibility exists |
773 | * of echo overrun before the next commit), then discard enough | |
774 | * data at the tail to prevent a subsequent overrun */ | |
775 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 776 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 777 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
778 | tail += 3; |
779 | else | |
780 | tail += 2; | |
781 | } else | |
782 | tail++; | |
783 | } | |
784 | ||
addaebcc | 785 | ldata->echo_tail = tail; |
bc5b1ec5 | 786 | return old_space - space; |
019ebdf9 PH |
787 | } |
788 | ||
789 | static void commit_echoes(struct tty_struct *tty) | |
790 | { | |
791 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 792 | size_t nr, old, echoed; |
cbfd0340 PH |
793 | size_t head; |
794 | ||
795 | head = ldata->echo_head; | |
1075a6e2 | 796 | ldata->echo_mark = head; |
cbfd0340 PH |
797 | old = ldata->echo_commit - ldata->echo_tail; |
798 | ||
799 | /* Process committed echoes if the accumulated # of bytes | |
800 | * is over the threshold (and try again each time another | |
801 | * block is accumulated) */ | |
802 | nr = head - ldata->echo_tail; | |
803 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
804 | return; | |
a88a69c9 | 805 | |
019ebdf9 | 806 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 807 | ldata->echo_commit = head; |
bc5b1ec5 | 808 | echoed = __process_echoes(tty); |
bddc7152 | 809 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 810 | |
bc5b1ec5 | 811 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
812 | tty->ops->flush_chars(tty); |
813 | } | |
814 | ||
019ebdf9 | 815 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
816 | { |
817 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 818 | size_t echoed; |
17bd7907 | 819 | |
e2613be5 | 820 | if (ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
821 | return; |
822 | ||
823 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 824 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 825 | echoed = __process_echoes(tty); |
019ebdf9 PH |
826 | mutex_unlock(&ldata->output_lock); |
827 | ||
bc5b1ec5 | 828 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 829 | tty->ops->flush_chars(tty); |
17bd7907 PH |
830 | } |
831 | ||
1075a6e2 | 832 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
833 | static void flush_echoes(struct tty_struct *tty) |
834 | { | |
835 | struct n_tty_data *ldata = tty->disc_data; | |
836 | ||
39434abd PH |
837 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
838 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
839 | return; |
840 | ||
841 | mutex_lock(&ldata->output_lock); | |
842 | ldata->echo_commit = ldata->echo_head; | |
843 | __process_echoes(tty); | |
844 | mutex_unlock(&ldata->output_lock); | |
845 | } | |
846 | ||
a88a69c9 JP |
847 | /** |
848 | * add_echo_byte - add a byte to the echo buffer | |
849 | * @c: unicode byte to echo | |
57c94121 | 850 | * @ldata: n_tty data |
a88a69c9 JP |
851 | * |
852 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
853 | */ |
854 | ||
cbfd0340 | 855 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 856 | { |
addaebcc | 857 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
858 | } |
859 | ||
860 | /** | |
861 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 862 | * @ldata: n_tty data |
a88a69c9 JP |
863 | * |
864 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
865 | */ |
866 | ||
57c94121 | 867 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 868 | { |
57c94121 JS |
869 | add_echo_byte(ECHO_OP_START, ldata); |
870 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
871 | } |
872 | ||
873 | /** | |
874 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 875 | * @ldata: n_tty data |
a88a69c9 JP |
876 | * |
877 | * Add an operation to the echo buffer to set the canon column | |
878 | * to the current column. | |
a88a69c9 JP |
879 | */ |
880 | ||
57c94121 | 881 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 882 | { |
57c94121 JS |
883 | add_echo_byte(ECHO_OP_START, ldata); |
884 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
885 | } |
886 | ||
887 | /** | |
888 | * echo_erase_tab - add operation to erase a tab | |
889 | * @num_chars: number of character columns already used | |
890 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 891 | * @ldata: n_tty data |
a88a69c9 JP |
892 | * |
893 | * Add an operation to the echo buffer to erase a tab. | |
894 | * | |
895 | * Called by the eraser function, which knows how many character | |
896 | * columns have been used since either a previous tab or the start | |
897 | * of input. This information will be used later, along with | |
898 | * canon column (if applicable), to go back the correct number | |
899 | * of columns. | |
a88a69c9 JP |
900 | */ |
901 | ||
902 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 903 | struct n_tty_data *ldata) |
a88a69c9 | 904 | { |
57c94121 JS |
905 | add_echo_byte(ECHO_OP_START, ldata); |
906 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
907 | |
908 | /* We only need to know this modulo 8 (tab spacing) */ | |
909 | num_chars &= 7; | |
910 | ||
911 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
912 | if (after_tab) | |
913 | num_chars |= 0x80; | |
300a6204 | 914 | |
57c94121 | 915 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
916 | } |
917 | ||
918 | /** | |
919 | * echo_char_raw - echo a character raw | |
920 | * @c: unicode byte to echo | |
921 | * @tty: terminal device | |
922 | * | |
923 | * Echo user input back onto the screen. This must be called only when | |
924 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
925 | * | |
926 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
927 | */ |
928 | ||
57c94121 | 929 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 930 | { |
a88a69c9 | 931 | if (c == ECHO_OP_START) { |
57c94121 JS |
932 | add_echo_byte(ECHO_OP_START, ldata); |
933 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 934 | } else { |
57c94121 | 935 | add_echo_byte(c, ldata); |
a88a69c9 | 936 | } |
a88a69c9 | 937 | } |
1da177e4 | 938 | |
1da177e4 | 939 | /** |
a88a69c9 | 940 | * echo_char - echo a character |
1da177e4 LT |
941 | * @c: unicode byte to echo |
942 | * @tty: terminal device | |
943 | * | |
4edf1827 | 944 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 945 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 946 | * |
62b26358 JP |
947 | * This variant tags control characters to be echoed as "^X" |
948 | * (where X is the letter representing the control char). | |
1da177e4 LT |
949 | */ |
950 | ||
951 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
952 | { | |
bddc7152 JS |
953 | struct n_tty_data *ldata = tty->disc_data; |
954 | ||
a88a69c9 | 955 | if (c == ECHO_OP_START) { |
57c94121 JS |
956 | add_echo_byte(ECHO_OP_START, ldata); |
957 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 958 | } else { |
62b26358 | 959 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
960 | add_echo_byte(ECHO_OP_START, ldata); |
961 | add_echo_byte(c, ldata); | |
a88a69c9 | 962 | } |
1da177e4 LT |
963 | } |
964 | ||
17b82060 | 965 | /** |
a88a69c9 | 966 | * finish_erasing - complete erase |
57c94121 | 967 | * @ldata: n_tty data |
17b82060 | 968 | */ |
a88a69c9 | 969 | |
57c94121 | 970 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 971 | { |
53c5ee2c | 972 | if (ldata->erasing) { |
57c94121 | 973 | echo_char_raw('/', ldata); |
53c5ee2c | 974 | ldata->erasing = 0; |
1da177e4 LT |
975 | } |
976 | } | |
977 | ||
978 | /** | |
979 | * eraser - handle erase function | |
980 | * @c: character input | |
981 | * @tty: terminal device | |
982 | * | |
3a4fa0a2 | 983 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
984 | * present in the stream from the driver layer. Handles the complexities |
985 | * of UTF-8 multibyte symbols. | |
17b82060 | 986 | * |
6d76bd26 PH |
987 | * n_tty_receive_buf()/producer path: |
988 | * caller holds non-exclusive termios_rwsem | |
989 | * modifies read_head | |
990 | * | |
991 | * Modifying the read_head is not considered a publish in this context | |
992 | * because canonical mode is active -- only canon_head publishes | |
1da177e4 | 993 | */ |
4edf1827 | 994 | |
1da177e4 LT |
995 | static void eraser(unsigned char c, struct tty_struct *tty) |
996 | { | |
53c5ee2c | 997 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 998 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
999 | size_t head; |
1000 | size_t cnt; | |
1001 | int seen_alnums; | |
1da177e4 | 1002 | |
ba2e68ac | 1003 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 1004 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
1005 | return; |
1006 | } | |
1007 | if (c == ERASE_CHAR(tty)) | |
1008 | kill_type = ERASE; | |
1009 | else if (c == WERASE_CHAR(tty)) | |
1010 | kill_type = WERASE; | |
1011 | else { | |
1012 | if (!L_ECHO(tty)) { | |
ba2e68ac | 1013 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
1014 | return; |
1015 | } | |
1016 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 1017 | ldata->read_head = ldata->canon_head; |
57c94121 | 1018 | finish_erasing(ldata); |
1da177e4 LT |
1019 | echo_char(KILL_CHAR(tty), tty); |
1020 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
1021 | if (L_ECHOK(tty)) | |
57c94121 | 1022 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1023 | return; |
1024 | } | |
1025 | kill_type = KILL; | |
1026 | } | |
1027 | ||
1028 | seen_alnums = 0; | |
ba2e68ac JS |
1029 | while (ldata->read_head != ldata->canon_head) { |
1030 | head = ldata->read_head; | |
1da177e4 LT |
1031 | |
1032 | /* erase a single possibly multibyte character */ | |
1033 | do { | |
bc5a5e3f PH |
1034 | head--; |
1035 | c = read_buf(ldata, head); | |
ba2e68ac | 1036 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1037 | |
1038 | /* do not partially erase */ | |
1039 | if (is_continuation(c, tty)) | |
1040 | break; | |
1041 | ||
1042 | if (kill_type == WERASE) { | |
1043 | /* Equivalent to BSD's ALTWERASE. */ | |
1044 | if (isalnum(c) || c == '_') | |
1045 | seen_alnums++; | |
1046 | else if (seen_alnums) | |
1047 | break; | |
1048 | } | |
bc5a5e3f | 1049 | cnt = ldata->read_head - head; |
ba2e68ac | 1050 | ldata->read_head = head; |
1da177e4 LT |
1051 | if (L_ECHO(tty)) { |
1052 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1053 | if (!ldata->erasing) { |
57c94121 | 1054 | echo_char_raw('\\', ldata); |
53c5ee2c | 1055 | ldata->erasing = 1; |
1da177e4 LT |
1056 | } |
1057 | /* if cnt > 1, output a multi-byte character */ | |
1058 | echo_char(c, tty); | |
1059 | while (--cnt > 0) { | |
bc5a5e3f PH |
1060 | head++; |
1061 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1062 | echo_move_back_col(ldata); |
1da177e4 LT |
1063 | } |
1064 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1065 | echo_char(ERASE_CHAR(tty), tty); | |
1066 | } else if (c == '\t') { | |
a88a69c9 JP |
1067 | unsigned int num_chars = 0; |
1068 | int after_tab = 0; | |
bc5a5e3f | 1069 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1070 | |
1071 | /* | |
1072 | * Count the columns used for characters | |
1073 | * since the start of input or after a | |
1074 | * previous tab. | |
1075 | * This info is used to go back the correct | |
1076 | * number of columns. | |
1077 | */ | |
ba2e68ac | 1078 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1079 | tail--; |
1080 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1081 | if (c == '\t') { |
1082 | after_tab = 1; | |
1083 | break; | |
300a6204 | 1084 | } else if (iscntrl(c)) { |
1da177e4 | 1085 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1086 | num_chars += 2; |
1087 | } else if (!is_continuation(c, tty)) { | |
1088 | num_chars++; | |
1089 | } | |
1da177e4 | 1090 | } |
57c94121 | 1091 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1092 | } else { |
1093 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1094 | echo_char_raw('\b', ldata); |
1095 | echo_char_raw(' ', ldata); | |
1096 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1097 | } |
1098 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1099 | echo_char_raw('\b', ldata); |
1100 | echo_char_raw(' ', ldata); | |
1101 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1102 | } |
1103 | } | |
1104 | } | |
1105 | if (kill_type == ERASE) | |
1106 | break; | |
1107 | } | |
ba2e68ac | 1108 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1109 | finish_erasing(ldata); |
1da177e4 LT |
1110 | } |
1111 | ||
1112 | /** | |
1113 | * isig - handle the ISIG optio | |
1114 | * @sig: signal | |
1115 | * @tty: terminal | |
1da177e4 | 1116 | * |
8c985d18 PH |
1117 | * Called when a signal is being sent due to terminal input. |
1118 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1119 | * |
8c985d18 | 1120 | * Locking: ctrl_lock |
1da177e4 | 1121 | */ |
4edf1827 | 1122 | |
4b293492 | 1123 | static void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1124 | { |
8c985d18 PH |
1125 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1126 | if (tty_pgrp) { | |
1127 | kill_pgrp(tty_pgrp, sig, 1); | |
1128 | put_pid(tty_pgrp); | |
1da177e4 LT |
1129 | } |
1130 | } | |
1131 | ||
1132 | /** | |
1133 | * n_tty_receive_break - handle break | |
1134 | * @tty: terminal | |
1135 | * | |
1136 | * An RS232 break event has been hit in the incoming bitstream. This | |
1137 | * can cause a variety of events depending upon the termios settings. | |
1138 | * | |
6d76bd26 PH |
1139 | * n_tty_receive_buf()/producer path: |
1140 | * caller holds non-exclusive termios_rwsem | |
1141 | * publishes read_head via put_tty_queue() | |
1142 | * | |
1143 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1144 | */ |
4edf1827 | 1145 | |
4b293492 | 1146 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1147 | { |
57c94121 JS |
1148 | struct n_tty_data *ldata = tty->disc_data; |
1149 | ||
1da177e4 LT |
1150 | if (I_IGNBRK(tty)) |
1151 | return; | |
1152 | if (I_BRKINT(tty)) { | |
8c985d18 PH |
1153 | isig(SIGINT, tty); |
1154 | if (!L_NOFLSH(tty)) { | |
6d76bd26 PH |
1155 | /* flushing needs exclusive termios_rwsem */ |
1156 | up_read(&tty->termios_rwsem); | |
8c985d18 PH |
1157 | n_tty_flush_buffer(tty); |
1158 | tty_driver_flush_buffer(tty); | |
6d76bd26 | 1159 | down_read(&tty->termios_rwsem); |
8c985d18 | 1160 | } |
1da177e4 LT |
1161 | return; |
1162 | } | |
1163 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1164 | put_tty_queue('\377', ldata); |
1165 | put_tty_queue('\0', ldata); | |
1da177e4 | 1166 | } |
57c94121 | 1167 | put_tty_queue('\0', ldata); |
6c67716d PH |
1168 | if (waitqueue_active(&tty->read_wait)) |
1169 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1170 | } |
1171 | ||
1172 | /** | |
1173 | * n_tty_receive_overrun - handle overrun reporting | |
1174 | * @tty: terminal | |
1175 | * | |
1176 | * Data arrived faster than we could process it. While the tty | |
1177 | * driver has flagged this the bits that were missed are gone | |
1178 | * forever. | |
1179 | * | |
1180 | * Called from the receive_buf path so single threaded. Does not | |
1181 | * need locking as num_overrun and overrun_time are function | |
1182 | * private. | |
1183 | */ | |
4edf1827 | 1184 | |
4b293492 | 1185 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1186 | { |
53c5ee2c | 1187 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1188 | char buf[64]; |
1189 | ||
53c5ee2c JS |
1190 | ldata->num_overrun++; |
1191 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1192 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1193 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1194 | tty_name(tty, buf), | |
53c5ee2c JS |
1195 | ldata->num_overrun); |
1196 | ldata->overrun_time = jiffies; | |
1197 | ldata->num_overrun = 0; | |
1da177e4 LT |
1198 | } |
1199 | } | |
1200 | ||
1201 | /** | |
1202 | * n_tty_receive_parity_error - error notifier | |
1203 | * @tty: terminal device | |
1204 | * @c: character | |
1205 | * | |
1206 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1207 | * the error case if necessary. |
1208 | * | |
1209 | * n_tty_receive_buf()/producer path: | |
1210 | * caller holds non-exclusive termios_rwsem | |
1211 | * publishes read_head via put_tty_queue() | |
1da177e4 | 1212 | */ |
4b293492 | 1213 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1214 | { |
57c94121 JS |
1215 | struct n_tty_data *ldata = tty->disc_data; |
1216 | ||
66528f90 PH |
1217 | if (I_INPCK(tty)) { |
1218 | if (I_IGNPAR(tty)) | |
1219 | return; | |
1220 | if (I_PARMRK(tty)) { | |
1221 | put_tty_queue('\377', ldata); | |
1222 | put_tty_queue('\0', ldata); | |
1223 | put_tty_queue(c, ldata); | |
1224 | } else | |
1225 | put_tty_queue('\0', ldata); | |
1226 | } else | |
57c94121 | 1227 | put_tty_queue(c, ldata); |
6c67716d PH |
1228 | if (waitqueue_active(&tty->read_wait)) |
1229 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1230 | } |
1231 | ||
b0ac50be PH |
1232 | static void |
1233 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1234 | { | |
1235 | if (!L_NOFLSH(tty)) { | |
1236 | /* flushing needs exclusive termios_rwsem */ | |
1237 | up_read(&tty->termios_rwsem); | |
1238 | n_tty_flush_buffer(tty); | |
1239 | tty_driver_flush_buffer(tty); | |
1240 | down_read(&tty->termios_rwsem); | |
1241 | } | |
1242 | if (I_IXON(tty)) | |
1243 | start_tty(tty); | |
1244 | if (L_ECHO(tty)) { | |
1245 | echo_char(c, tty); | |
1246 | commit_echoes(tty); | |
e2613be5 PH |
1247 | } else |
1248 | process_echoes(tty); | |
b0ac50be PH |
1249 | isig(signal, tty); |
1250 | return; | |
1251 | } | |
1252 | ||
1da177e4 LT |
1253 | /** |
1254 | * n_tty_receive_char - perform processing | |
1255 | * @tty: terminal device | |
1256 | * @c: character | |
1257 | * | |
1258 | * Process an individual character of input received from the driver. | |
4edf1827 | 1259 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1260 | * driver above. |
6d76bd26 PH |
1261 | * |
1262 | * n_tty_receive_buf()/producer path: | |
1263 | * caller holds non-exclusive termios_rwsem | |
1264 | * publishes canon_head if canonical mode is active | |
1265 | * otherwise, publishes read_head via put_tty_queue() | |
e60d27c4 PH |
1266 | * |
1267 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1268 | */ |
1269 | ||
e60d27c4 | 1270 | static int |
4b1f79c2 | 1271 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1272 | { |
53c5ee2c | 1273 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1274 | |
1da177e4 LT |
1275 | if (I_IXON(tty)) { |
1276 | if (c == START_CHAR(tty)) { | |
1277 | start_tty(tty); | |
e2613be5 | 1278 | process_echoes(tty); |
e60d27c4 | 1279 | return 0; |
1da177e4 LT |
1280 | } |
1281 | if (c == STOP_CHAR(tty)) { | |
1282 | stop_tty(tty); | |
e60d27c4 | 1283 | return 0; |
1da177e4 LT |
1284 | } |
1285 | } | |
575537b3 | 1286 | |
1da177e4 | 1287 | if (L_ISIG(tty)) { |
b0ac50be PH |
1288 | if (c == INTR_CHAR(tty)) { |
1289 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1290 | return 0; |
b0ac50be PH |
1291 | } else if (c == QUIT_CHAR(tty)) { |
1292 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1293 | return 0; |
b0ac50be PH |
1294 | } else if (c == SUSP_CHAR(tty)) { |
1295 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1296 | return 0; |
1da177e4 LT |
1297 | } |
1298 | } | |
575537b3 | 1299 | |
855df3c0 PH |
1300 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1301 | start_tty(tty); | |
1302 | process_echoes(tty); | |
1303 | } | |
1304 | ||
575537b3 JP |
1305 | if (c == '\r') { |
1306 | if (I_IGNCR(tty)) | |
e60d27c4 | 1307 | return 0; |
575537b3 JP |
1308 | if (I_ICRNL(tty)) |
1309 | c = '\n'; | |
1310 | } else if (c == '\n' && I_INLCR(tty)) | |
1311 | c = '\r'; | |
1312 | ||
53c5ee2c | 1313 | if (ldata->icanon) { |
1da177e4 LT |
1314 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1315 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1316 | eraser(c, tty); | |
17bd7907 | 1317 | commit_echoes(tty); |
e60d27c4 | 1318 | return 0; |
1da177e4 LT |
1319 | } |
1320 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1321 | ldata->lnext = 1; |
1da177e4 | 1322 | if (L_ECHO(tty)) { |
57c94121 | 1323 | finish_erasing(ldata); |
1da177e4 | 1324 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1325 | echo_char_raw('^', ldata); |
1326 | echo_char_raw('\b', ldata); | |
17bd7907 | 1327 | commit_echoes(tty); |
1da177e4 LT |
1328 | } |
1329 | } | |
e60d27c4 | 1330 | return 1; |
1da177e4 | 1331 | } |
e60d27c4 | 1332 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1333 | size_t tail = ldata->canon_head; |
1da177e4 | 1334 | |
57c94121 | 1335 | finish_erasing(ldata); |
1da177e4 | 1336 | echo_char(c, tty); |
57c94121 | 1337 | echo_char_raw('\n', ldata); |
ba2e68ac | 1338 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1339 | echo_char(read_buf(ldata, tail), tty); |
1340 | tail++; | |
1da177e4 | 1341 | } |
17bd7907 | 1342 | commit_echoes(tty); |
e60d27c4 | 1343 | return 0; |
1da177e4 LT |
1344 | } |
1345 | if (c == '\n') { | |
acc71bba | 1346 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1347 | echo_char_raw('\n', ldata); |
17bd7907 | 1348 | commit_echoes(tty); |
1da177e4 LT |
1349 | } |
1350 | goto handle_newline; | |
1351 | } | |
1352 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1353 | c = __DISABLED_CHAR; |
1354 | goto handle_newline; | |
1355 | } | |
1356 | if ((c == EOL_CHAR(tty)) || | |
1357 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1358 | /* | |
1359 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1360 | */ | |
1361 | if (L_ECHO(tty)) { | |
1da177e4 | 1362 | /* Record the column of first canon char. */ |
ba2e68ac | 1363 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1364 | echo_set_canon_col(ldata); |
1da177e4 | 1365 | echo_char(c, tty); |
17bd7907 | 1366 | commit_echoes(tty); |
1da177e4 LT |
1367 | } |
1368 | /* | |
1369 | * XXX does PARMRK doubling happen for | |
1370 | * EOL_CHAR and EOL2_CHAR? | |
1371 | */ | |
001ba923 | 1372 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
57c94121 | 1373 | put_tty_queue(c, ldata); |
1da177e4 | 1374 | |
4edf1827 | 1375 | handle_newline: |
bc5a5e3f | 1376 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1377 | put_tty_queue(c, ldata); |
ba2e68ac | 1378 | ldata->canon_head = ldata->read_head; |
1da177e4 LT |
1379 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1380 | if (waitqueue_active(&tty->read_wait)) | |
1381 | wake_up_interruptible(&tty->read_wait); | |
e60d27c4 | 1382 | return 0; |
1da177e4 LT |
1383 | } |
1384 | } | |
4edf1827 | 1385 | |
acc71bba | 1386 | if (L_ECHO(tty)) { |
57c94121 | 1387 | finish_erasing(ldata); |
1da177e4 | 1388 | if (c == '\n') |
57c94121 | 1389 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1390 | else { |
1391 | /* Record the column of first canon char. */ | |
ba2e68ac | 1392 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1393 | echo_set_canon_col(ldata); |
1da177e4 LT |
1394 | echo_char(c, tty); |
1395 | } | |
17bd7907 | 1396 | commit_echoes(tty); |
1da177e4 LT |
1397 | } |
1398 | ||
001ba923 PH |
1399 | /* PARMRK doubling check */ |
1400 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
57c94121 | 1401 | put_tty_queue(c, ldata); |
1da177e4 | 1402 | |
57c94121 | 1403 | put_tty_queue(c, ldata); |
e60d27c4 | 1404 | return 0; |
4edf1827 | 1405 | } |
1da177e4 | 1406 | |
e60d27c4 PH |
1407 | static inline void |
1408 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1409 | { |
1410 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1411 | |
e60d27c4 PH |
1412 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1413 | start_tty(tty); | |
1414 | process_echoes(tty); | |
1415 | } | |
1416 | if (L_ECHO(tty)) { | |
1417 | finish_erasing(ldata); | |
1418 | /* Record the column of first canon char. */ | |
1419 | if (ldata->canon_head == ldata->read_head) | |
1420 | echo_set_canon_col(ldata); | |
1421 | echo_char(c, tty); | |
1422 | commit_echoes(tty); | |
4b1f79c2 | 1423 | } |
001ba923 PH |
1424 | /* PARMRK doubling check */ |
1425 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
e60d27c4 PH |
1426 | put_tty_queue(c, ldata); |
1427 | put_tty_queue(c, ldata); | |
1428 | } | |
4b1f79c2 | 1429 | |
eb3e4668 | 1430 | static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
e60d27c4 PH |
1431 | { |
1432 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1433 | } |
1434 | ||
7de971b0 PH |
1435 | static inline void |
1436 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1437 | { | |
1438 | struct n_tty_data *ldata = tty->disc_data; | |
1439 | ||
e60d27c4 PH |
1440 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1441 | start_tty(tty); | |
1442 | process_echoes(tty); | |
7de971b0 | 1443 | } |
e60d27c4 PH |
1444 | if (L_ECHO(tty)) { |
1445 | finish_erasing(ldata); | |
1446 | /* Record the column of first canon char. */ | |
1447 | if (ldata->canon_head == ldata->read_head) | |
1448 | echo_set_canon_col(ldata); | |
1449 | echo_char(c, tty); | |
1450 | commit_echoes(tty); | |
1451 | } | |
1452 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1453 | } |
1454 | ||
8dc4b25d | 1455 | static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) |
ad0cc7ba PH |
1456 | { |
1457 | if (I_ISTRIP(tty)) | |
1458 | c &= 0x7f; | |
1459 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1460 | c = tolower(c); | |
1461 | ||
1462 | if (I_IXON(tty)) { | |
1463 | if (c == STOP_CHAR(tty)) | |
1464 | stop_tty(tty); | |
1465 | else if (c == START_CHAR(tty) || | |
1466 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1467 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1468 | c != SUSP_CHAR(tty))) { | |
1469 | start_tty(tty); | |
1470 | process_echoes(tty); | |
1471 | } | |
1472 | } | |
1473 | } | |
1474 | ||
d2f8d7ab PH |
1475 | static void |
1476 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1477 | { | |
1478 | char buf[64]; | |
1479 | ||
1480 | switch (flag) { | |
1481 | case TTY_BREAK: | |
1482 | n_tty_receive_break(tty); | |
1483 | break; | |
1484 | case TTY_PARITY: | |
1485 | case TTY_FRAME: | |
1486 | n_tty_receive_parity_error(tty, c); | |
1487 | break; | |
1488 | case TTY_OVERRUN: | |
1489 | n_tty_receive_overrun(tty); | |
1490 | break; | |
1491 | default: | |
1492 | printk(KERN_ERR "%s: unknown flag %d\n", | |
1493 | tty_name(tty, buf), flag); | |
1494 | break; | |
1495 | } | |
1496 | } | |
1497 | ||
e60d27c4 PH |
1498 | static void |
1499 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1500 | { | |
1501 | struct n_tty_data *ldata = tty->disc_data; | |
1502 | ||
1503 | ldata->lnext = 0; | |
1504 | if (likely(flag == TTY_NORMAL)) { | |
1505 | if (I_ISTRIP(tty)) | |
1506 | c &= 0x7f; | |
1507 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1508 | c = tolower(c); | |
1509 | n_tty_receive_char(tty, c); | |
1510 | } else | |
1511 | n_tty_receive_char_flagged(tty, c, flag); | |
1512 | } | |
1513 | ||
1da177e4 LT |
1514 | /** |
1515 | * n_tty_receive_buf - data receive | |
1516 | * @tty: terminal device | |
1517 | * @cp: buffer | |
1518 | * @fp: flag buffer | |
1519 | * @count: characters | |
1520 | * | |
1521 | * Called by the terminal driver when a block of characters has | |
1522 | * been received. This function must be called from soft contexts | |
1523 | * not from interrupt context. The driver is responsible for making | |
1524 | * calls one at a time and in order (or using flush_to_ldisc) | |
6d76bd26 PH |
1525 | * |
1526 | * n_tty_receive_buf()/producer path: | |
1527 | * claims non-exclusive termios_rwsem | |
1528 | * publishes read_head and canon_head | |
1da177e4 | 1529 | */ |
4edf1827 | 1530 | |
4a23a4df PH |
1531 | static void |
1532 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1533 | char *fp, int count) | |
1534 | { | |
1535 | struct n_tty_data *ldata = tty->disc_data; | |
1536 | size_t n, head; | |
1537 | ||
1538 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1539 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1540 | n = min_t(size_t, count, n); | |
1541 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1542 | ldata->read_head += n; | |
1543 | cp += n; | |
1544 | count -= n; | |
1545 | ||
1546 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1547 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1548 | n = min_t(size_t, count, n); | |
1549 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1550 | ldata->read_head += n; | |
1551 | } | |
1552 | ||
554117bd PH |
1553 | static void |
1554 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1555 | char *fp, int count) | |
1556 | { | |
1557 | struct n_tty_data *ldata = tty->disc_data; | |
1558 | char flag = TTY_NORMAL; | |
1559 | ||
1560 | while (count--) { | |
1561 | if (fp) | |
1562 | flag = *fp++; | |
1563 | if (likely(flag == TTY_NORMAL)) | |
1564 | put_tty_queue(*cp++, ldata); | |
1565 | else | |
1566 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1567 | } | |
1568 | } | |
1569 | ||
ad0cc7ba PH |
1570 | static void |
1571 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1572 | char *fp, int count) | |
1573 | { | |
1574 | char flag = TTY_NORMAL; | |
1575 | ||
1576 | while (count--) { | |
1577 | if (fp) | |
1578 | flag = *fp++; | |
1579 | if (likely(flag == TTY_NORMAL)) | |
1580 | n_tty_receive_char_closing(tty, *cp++); | |
1581 | else | |
1582 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1583 | } | |
1584 | } | |
1585 | ||
7d88d637 PH |
1586 | static void |
1587 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1588 | char *fp, int count) |
1589 | { | |
1590 | struct n_tty_data *ldata = tty->disc_data; | |
1591 | char flag = TTY_NORMAL; | |
1592 | ||
1593 | while (count--) { | |
1594 | if (fp) | |
1595 | flag = *fp++; | |
1596 | if (likely(flag == TTY_NORMAL)) { | |
1597 | unsigned char c = *cp++; | |
1598 | ||
1599 | if (I_ISTRIP(tty)) | |
1600 | c &= 0x7f; | |
1601 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1602 | c = tolower(c); | |
1603 | if (L_EXTPROC(tty)) { | |
1604 | put_tty_queue(c, ldata); | |
1605 | continue; | |
1606 | } | |
e60d27c4 PH |
1607 | if (!test_bit(c, ldata->char_map)) |
1608 | n_tty_receive_char_inline(tty, c); | |
1609 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1610 | if (fp) | |
1611 | flag = *fp++; | |
1612 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1613 | count--; | |
1614 | } | |
6baad008 PH |
1615 | } else |
1616 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1617 | } | |
1618 | } | |
1619 | ||
1620 | static void | |
1621 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1622 | char *fp, int count) | |
7d88d637 | 1623 | { |
e60d27c4 | 1624 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1625 | char flag = TTY_NORMAL; |
1626 | ||
1627 | while (count--) { | |
1628 | if (fp) | |
1629 | flag = *fp++; | |
e60d27c4 PH |
1630 | if (likely(flag == TTY_NORMAL)) { |
1631 | unsigned char c = *cp++; | |
1632 | ||
1633 | if (!test_bit(c, ldata->char_map)) | |
1634 | n_tty_receive_char_fast(tty, c); | |
1635 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1636 | if (fp) | |
1637 | flag = *fp++; | |
1638 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1639 | count--; | |
1640 | } | |
1641 | } else | |
7d88d637 PH |
1642 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1643 | } | |
1644 | } | |
1645 | ||
24a89d1c PH |
1646 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1647 | char *fp, int count) | |
1da177e4 | 1648 | { |
53c5ee2c | 1649 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1650 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1651 | |
4a23a4df PH |
1652 | if (ldata->real_raw) |
1653 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1654 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1655 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1656 | else if (tty->closing && !L_EXTPROC(tty)) |
1657 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1658 | else { |
e60d27c4 PH |
1659 | if (ldata->lnext) { |
1660 | char flag = TTY_NORMAL; | |
1661 | ||
1662 | if (fp) | |
1663 | flag = *fp++; | |
1664 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1665 | count--; | |
1666 | } | |
1667 | ||
7de971b0 | 1668 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1669 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1670 | else | |
1671 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1672 | |
1673 | flush_echoes(tty); | |
f34d7a5b AC |
1674 | if (tty->ops->flush_chars) |
1675 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1676 | } |
1677 | ||
ce74117a | 1678 | if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) || |
26df6d13 | 1679 | L_EXTPROC(tty)) { |
1da177e4 LT |
1680 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1681 | if (waitqueue_active(&tty->read_wait)) | |
1682 | wake_up_interruptible(&tty->read_wait); | |
1683 | } | |
1da177e4 LT |
1684 | } |
1685 | ||
5c32d123 PH |
1686 | static int |
1687 | n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, | |
1688 | char *fp, int count, int flow) | |
24a89d1c PH |
1689 | { |
1690 | struct n_tty_data *ldata = tty->disc_data; | |
19e2ad6a | 1691 | int room, n, rcvd = 0; |
24a89d1c | 1692 | |
9356b535 PH |
1693 | down_read(&tty->termios_rwsem); |
1694 | ||
19e2ad6a PH |
1695 | while (1) { |
1696 | room = receive_room(tty); | |
1697 | n = min(count, room); | |
1698 | if (!n) { | |
5c32d123 | 1699 | if (flow && !room) |
19e2ad6a PH |
1700 | ldata->no_room = 1; |
1701 | break; | |
1702 | } | |
1703 | __receive_buf(tty, cp, fp, n); | |
1704 | cp += n; | |
1705 | if (fp) | |
1706 | fp += n; | |
1707 | count -= n; | |
1708 | rcvd += n; | |
4a23a4df | 1709 | } |
24a89d1c | 1710 | |
19e2ad6a PH |
1711 | tty->receive_room = room; |
1712 | n_tty_check_throttle(tty); | |
9356b535 PH |
1713 | up_read(&tty->termios_rwsem); |
1714 | ||
19e2ad6a | 1715 | return rcvd; |
24a89d1c PH |
1716 | } |
1717 | ||
5c32d123 PH |
1718 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1719 | char *fp, int count) | |
1720 | { | |
1721 | n_tty_receive_buf_common(tty, cp, fp, count, 0); | |
1722 | } | |
1723 | ||
1724 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1725 | char *fp, int count) | |
1726 | { | |
1727 | return n_tty_receive_buf_common(tty, cp, fp, count, 1); | |
1728 | } | |
1729 | ||
1da177e4 LT |
1730 | int is_ignored(int sig) |
1731 | { | |
1732 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1733 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1734 | } |
1735 | ||
1736 | /** | |
1737 | * n_tty_set_termios - termios data changed | |
1738 | * @tty: terminal | |
1739 | * @old: previous data | |
1740 | * | |
1741 | * Called by the tty layer when the user changes termios flags so | |
1742 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1743 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1744 | * guaranteed that this function will not be re-entered or in progress |
1745 | * when the ldisc is closed. | |
17b82060 | 1746 | * |
6a1c0680 | 1747 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1748 | */ |
4edf1827 AC |
1749 | |
1750 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1751 | { |
53c5ee2c | 1752 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1753 | |
c786f74e | 1754 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { |
3fe780b3 | 1755 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1756 | ldata->line_start = ldata->read_tail; |
1757 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1758 | ldata->canon_head = ldata->read_tail; | |
1759 | ldata->push = 0; | |
1760 | } else { | |
1761 | set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), | |
1762 | ldata->read_flags); | |
1763 | ldata->canon_head = ldata->read_head; | |
1764 | ldata->push = 1; | |
1765 | } | |
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 | */ | |
e2613be5 | 1824 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { |
dab73b4e | 1825 | start_tty(tty); |
e2613be5 PH |
1826 | process_echoes(tty); |
1827 | } | |
dab73b4e | 1828 | |
f34d7a5b | 1829 | /* The termios change make the tty ready for I/O */ |
6c67716d PH |
1830 | if (waitqueue_active(&tty->write_wait)) |
1831 | wake_up_interruptible(&tty->write_wait); | |
1832 | if (waitqueue_active(&tty->read_wait)) | |
1833 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1834 | } |
1835 | ||
1836 | /** | |
1837 | * n_tty_close - close the ldisc for this tty | |
1838 | * @tty: device | |
1839 | * | |
4edf1827 AC |
1840 | * Called from the terminal layer when this line discipline is |
1841 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1842 | * discipline change. The function will not be called while other |
1843 | * ldisc methods are in progress. | |
1844 | */ | |
4edf1827 | 1845 | |
1da177e4 LT |
1846 | static void n_tty_close(struct tty_struct *tty) |
1847 | { | |
70ece7a7 JS |
1848 | struct n_tty_data *ldata = tty->disc_data; |
1849 | ||
79901317 PH |
1850 | if (tty->link) |
1851 | n_tty_packet_mode_flush(tty); | |
1852 | ||
20bafb3d | 1853 | vfree(ldata); |
70ece7a7 | 1854 | tty->disc_data = NULL; |
1da177e4 LT |
1855 | } |
1856 | ||
1857 | /** | |
1858 | * n_tty_open - open an ldisc | |
1859 | * @tty: terminal to open | |
1860 | * | |
4edf1827 | 1861 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1862 | * terminal device. Can sleep. Called serialized so that no |
1863 | * other events will occur in parallel. No further open will occur | |
1864 | * until a close. | |
1865 | */ | |
1866 | ||
1867 | static int n_tty_open(struct tty_struct *tty) | |
1868 | { | |
70ece7a7 JS |
1869 | struct n_tty_data *ldata; |
1870 | ||
20bafb3d PH |
1871 | /* Currently a malloc failure here can panic */ |
1872 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1873 | if (!ldata) |
1874 | goto err; | |
1875 | ||
53c5ee2c | 1876 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1877 | mutex_init(&ldata->atomic_read_lock); |
1878 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1879 | |
70ece7a7 | 1880 | tty->disc_data = ldata; |
b66f4fa5 | 1881 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1882 | ldata->column = 0; |
20bafb3d | 1883 | ldata->canon_column = 0; |
f6c8dbe6 | 1884 | ldata->minimum_to_wake = 1; |
20bafb3d PH |
1885 | ldata->num_overrun = 0; |
1886 | ldata->no_room = 0; | |
1887 | ldata->lnext = 0; | |
1da177e4 | 1888 | tty->closing = 0; |
b66f4fa5 PH |
1889 | /* indicate buffer work may resume */ |
1890 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1891 | n_tty_set_termios(tty, NULL); | |
1892 | tty_unthrottle(tty); | |
70ece7a7 | 1893 | |
1da177e4 | 1894 | return 0; |
70ece7a7 | 1895 | err: |
b91939f5 | 1896 | return -ENOMEM; |
1da177e4 LT |
1897 | } |
1898 | ||
eafbe67f | 1899 | static inline int input_available_p(struct tty_struct *tty, int poll) |
1da177e4 | 1900 | { |
53c5ee2c | 1901 | struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1902 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1903 | |
25e8d0ed PH |
1904 | if (ldata->icanon && !L_EXTPROC(tty)) |
1905 | return ldata->canon_head != ldata->read_tail; | |
1906 | else | |
1907 | return read_cnt(ldata) >= amt; | |
1da177e4 LT |
1908 | } |
1909 | ||
1910 | /** | |
bbd20759 | 1911 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1912 | * @tty: terminal device |
1913 | * @b: user data | |
1914 | * @nr: size of data | |
1915 | * | |
11a96d18 | 1916 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1917 | * ICANON is off; it copies characters straight from the tty queue to |
1918 | * user space directly. It can be profitably called twice; once to | |
1919 | * drain the space from the tail pointer to the (physical) end of the | |
1920 | * buffer, and once to drain the space from the (physical) beginning of | |
1921 | * the buffer to head pointer. | |
1922 | * | |
bddc7152 | 1923 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1924 | * |
6d76bd26 PH |
1925 | * n_tty_read()/consumer path: |
1926 | * caller holds non-exclusive termios_rwsem | |
1927 | * read_tail published | |
1da177e4 | 1928 | */ |
4edf1827 | 1929 | |
33f0f88f | 1930 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1931 | unsigned char __user **b, |
1932 | size_t *nr) | |
1933 | ||
1934 | { | |
53c5ee2c | 1935 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1936 | int retval; |
1937 | size_t n; | |
3fa10cc8 | 1938 | bool is_eof; |
bc5a5e3f | 1939 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1940 | |
1941 | retval = 0; | |
bc5a5e3f | 1942 | n = min(read_cnt(ldata), N_TTY_BUF_SIZE - tail); |
1da177e4 | 1943 | n = min(*nr, n); |
1da177e4 | 1944 | if (n) { |
bc5a5e3f | 1945 | retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
1da177e4 | 1946 | n -= retval; |
bc5a5e3f PH |
1947 | is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); |
1948 | tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, | |
53c5ee2c | 1949 | ldata->icanon); |
bc5a5e3f | 1950 | ldata->read_tail += n; |
26df6d13 | 1951 | /* Turn single EOF into zero-length read */ |
ce74117a | 1952 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !read_cnt(ldata)) |
3fa10cc8 | 1953 | n = 0; |
1da177e4 LT |
1954 | *b += n; |
1955 | *nr -= n; | |
1956 | } | |
1957 | return retval; | |
1958 | } | |
1959 | ||
88bb0de3 | 1960 | /** |
32f13521 | 1961 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1962 | * @tty: terminal device |
1963 | * @b: user data | |
1964 | * @nr: size of data | |
1965 | * | |
1966 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1967 | * it copies one line of input up to and including the line-delimiting |
1968 | * character into the user-space buffer. | |
88bb0de3 | 1969 | * |
4d0ed182 PH |
1970 | * NB: When termios is changed from non-canonical to canonical mode and |
1971 | * the read buffer contains data, n_tty_set_termios() simulates an EOF | |
1972 | * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. | |
1973 | * This causes data already processed as input to be immediately available | |
1974 | * as input although a newline has not been received. | |
1975 | * | |
88bb0de3 | 1976 | * Called under the atomic_read_lock mutex |
6d76bd26 PH |
1977 | * |
1978 | * n_tty_read()/consumer path: | |
1979 | * caller holds non-exclusive termios_rwsem | |
1980 | * read_tail published | |
88bb0de3 PH |
1981 | */ |
1982 | ||
32f13521 PH |
1983 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
1984 | unsigned char __user **b, | |
1985 | size_t *nr) | |
88bb0de3 PH |
1986 | { |
1987 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 1988 | size_t n, size, more, c; |
bc5a5e3f PH |
1989 | size_t eol; |
1990 | size_t tail; | |
1991 | int ret, found = 0; | |
40d5e090 | 1992 | bool eof_push = 0; |
88bb0de3 PH |
1993 | |
1994 | /* N.B. avoid overrun if nr == 0 */ | |
ce74117a | 1995 | n = min(*nr, read_cnt(ldata)); |
6d76bd26 | 1996 | if (!n) |
32f13521 | 1997 | return 0; |
88bb0de3 | 1998 | |
bc5a5e3f | 1999 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
2000 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
2001 | ||
bc5a5e3f | 2002 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2003 | __func__, *nr, tail, n, size); |
2004 | ||
2005 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2006 | more = n - (size - tail); | |
2007 | if (eol == N_TTY_BUF_SIZE && more) { | |
2008 | /* scan wrapped without finding set bit */ | |
2009 | eol = find_next_bit(ldata->read_flags, more, 0); | |
2010 | if (eol != more) | |
2011 | found = 1; | |
2012 | } else if (eol != size) | |
2013 | found = 1; | |
2014 | ||
2015 | size = N_TTY_BUF_SIZE - tail; | |
c77569d2 PH |
2016 | n = eol - tail; |
2017 | if (n > 4096) | |
2018 | n += 4096; | |
2019 | n += found; | |
32f13521 PH |
2020 | c = n; |
2021 | ||
4d0ed182 | 2022 | if (found && !ldata->push && read_buf(ldata, eol) == __DISABLED_CHAR) { |
32f13521 | 2023 | n--; |
40d5e090 PH |
2024 | eof_push = !n && ldata->read_tail != ldata->line_start; |
2025 | } | |
32f13521 | 2026 | |
bc5a5e3f | 2027 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", |
32f13521 PH |
2028 | __func__, eol, found, n, c, size, more); |
2029 | ||
32f13521 | 2030 | if (n > size) { |
bc5a5e3f | 2031 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), size); |
32f13521 PH |
2032 | if (ret) |
2033 | return -EFAULT; | |
2034 | ret = copy_to_user(*b + size, ldata->read_buf, n - size); | |
2035 | } else | |
bc5a5e3f | 2036 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
32f13521 PH |
2037 | |
2038 | if (ret) | |
2039 | return -EFAULT; | |
2040 | *b += n; | |
2041 | *nr -= n; | |
2042 | ||
a73d3d69 | 2043 | if (found) |
6d76bd26 | 2044 | clear_bit(eol, ldata->read_flags); |
4e857c58 | 2045 | smp_mb__after_atomic(); |
6d76bd26 | 2046 | ldata->read_tail += c; |
88bb0de3 | 2047 | |
40d5e090 | 2048 | if (found) { |
4d0ed182 PH |
2049 | if (!ldata->push) |
2050 | ldata->line_start = ldata->read_tail; | |
2051 | else | |
2052 | ldata->push = 0; | |
32f13521 | 2053 | tty_audit_push(tty); |
40d5e090 PH |
2054 | } |
2055 | return eof_push ? -EAGAIN : 0; | |
88bb0de3 PH |
2056 | } |
2057 | ||
cc4191dc | 2058 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2059 | size_t, loff_t *); |
1da177e4 LT |
2060 | |
2061 | /** | |
2062 | * job_control - check job control | |
2063 | * @tty: tty | |
2064 | * @file: file handle | |
2065 | * | |
2066 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2067 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2068 | * error code if action should be taken. |
04f378b1 | 2069 | * |
01a5e440 PH |
2070 | * Locking: redirected write test is safe |
2071 | * current->signal->tty check is safe | |
2072 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2073 | */ |
4edf1827 | 2074 | |
1da177e4 LT |
2075 | static int job_control(struct tty_struct *tty, struct file *file) |
2076 | { | |
2077 | /* Job control check -- must be done at start and after | |
2078 | every sleep (POSIX.1 7.1.1.4). */ | |
2079 | /* NOTE: not yet done after every sleep pending a thorough | |
2080 | check of the logic of this change. -- jlc */ | |
2081 | /* don't stop on /dev/console */ | |
01a5e440 PH |
2082 | if (file->f_op->write == redirected_tty_write || |
2083 | current->signal->tty != tty) | |
2084 | return 0; | |
2085 | ||
2086 | spin_lock_irq(&tty->ctrl_lock); | |
2087 | if (!tty->pgrp) | |
2088 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
2089 | else if (task_pgrp(current) != tty->pgrp) { | |
2090 | spin_unlock_irq(&tty->ctrl_lock); | |
2091 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
2092 | return -EIO; | |
2093 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
2094 | set_thread_flag(TIF_SIGPENDING); | |
2095 | return -ERESTARTSYS; | |
1da177e4 | 2096 | } |
01a5e440 | 2097 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
2098 | return 0; |
2099 | } | |
4edf1827 | 2100 | |
1da177e4 LT |
2101 | |
2102 | /** | |
11a96d18 | 2103 | * n_tty_read - read function for tty |
1da177e4 LT |
2104 | * @tty: tty device |
2105 | * @file: file object | |
2106 | * @buf: userspace buffer pointer | |
2107 | * @nr: size of I/O | |
2108 | * | |
2109 | * Perform reads for the line discipline. We are guaranteed that the | |
2110 | * line discipline will not be closed under us but we may get multiple | |
2111 | * parallel readers and must handle this ourselves. We may also get | |
2112 | * a hangup. Always called in user context, may sleep. | |
2113 | * | |
2114 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2115 | * |
2116 | * n_tty_read()/consumer path: | |
2117 | * claims non-exclusive termios_rwsem | |
2118 | * publishes read_tail | |
1da177e4 | 2119 | */ |
4edf1827 | 2120 | |
11a96d18 | 2121 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2122 | unsigned char __user *buf, size_t nr) |
2123 | { | |
53c5ee2c | 2124 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2125 | unsigned char __user *b = buf; |
2126 | DECLARE_WAITQUEUE(wait, current); | |
2127 | int c; | |
2128 | int minimum, time; | |
2129 | ssize_t retval = 0; | |
1da177e4 LT |
2130 | long timeout; |
2131 | unsigned long flags; | |
04f378b1 | 2132 | int packet; |
1da177e4 | 2133 | |
1da177e4 | 2134 | c = job_control(tty, file); |
4edf1827 | 2135 | if (c < 0) |
1da177e4 | 2136 | return c; |
4edf1827 | 2137 | |
aefceaf4 PH |
2138 | /* |
2139 | * Internal serialization of reads. | |
2140 | */ | |
2141 | if (file->f_flags & O_NONBLOCK) { | |
2142 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2143 | return -EAGAIN; | |
2144 | } else { | |
2145 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2146 | return -ERESTARTSYS; | |
2147 | } | |
2148 | ||
9356b535 PH |
2149 | down_read(&tty->termios_rwsem); |
2150 | ||
1da177e4 LT |
2151 | minimum = time = 0; |
2152 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2153 | if (!ldata->icanon) { |
1da177e4 LT |
2154 | minimum = MIN_CHAR(tty); |
2155 | if (minimum) { | |
a6e54319 | 2156 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2157 | if (time) |
f6c8dbe6 | 2158 | ldata->minimum_to_wake = 1; |
1da177e4 | 2159 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
2160 | (ldata->minimum_to_wake > minimum)) |
2161 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 2162 | } else { |
a6e54319 | 2163 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2164 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2165 | } |
2166 | } | |
2167 | ||
04f378b1 | 2168 | packet = tty->packet; |
1da177e4 LT |
2169 | |
2170 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2171 | while (nr) { |
2172 | /* First test for status change. */ | |
04f378b1 | 2173 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2174 | unsigned char cs; |
2175 | if (b != buf) | |
2176 | break; | |
04f378b1 | 2177 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
2178 | cs = tty->link->ctrl_status; |
2179 | tty->link->ctrl_status = 0; | |
04f378b1 | 2180 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 2181 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2182 | retval = -EFAULT; |
2183 | b--; | |
2184 | break; | |
2185 | } | |
2186 | nr--; | |
2187 | break; | |
2188 | } | |
2189 | /* This statement must be first before checking for input | |
2190 | so that any interrupt will set the state back to | |
2191 | TASK_RUNNING. */ | |
2192 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 2193 | |
f6c8dbe6 | 2194 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2195 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2196 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2197 | |
1da177e4 LT |
2198 | if (!input_available_p(tty, 0)) { |
2199 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
f8747d4a PH |
2200 | up_read(&tty->termios_rwsem); |
2201 | tty_flush_to_ldisc(tty); | |
2202 | down_read(&tty->termios_rwsem); | |
2203 | if (!input_available_p(tty, 0)) { | |
2204 | retval = -EIO; | |
2205 | break; | |
2206 | } | |
2207 | } else { | |
2208 | if (tty_hung_up_p(file)) | |
2209 | break; | |
2210 | if (!timeout) | |
2211 | break; | |
2212 | if (file->f_flags & O_NONBLOCK) { | |
2213 | retval = -EAGAIN; | |
2214 | break; | |
2215 | } | |
2216 | if (signal_pending(current)) { | |
2217 | retval = -ERESTARTSYS; | |
2218 | break; | |
2219 | } | |
2220 | n_tty_set_room(tty); | |
2221 | up_read(&tty->termios_rwsem); | |
9356b535 | 2222 | |
f8747d4a | 2223 | timeout = schedule_timeout(timeout); |
9356b535 | 2224 | |
f8747d4a PH |
2225 | down_read(&tty->termios_rwsem); |
2226 | continue; | |
2227 | } | |
1da177e4 LT |
2228 | } |
2229 | __set_current_state(TASK_RUNNING); | |
2230 | ||
2231 | /* Deal with packet mode. */ | |
04f378b1 | 2232 | if (packet && b == buf) { |
522ed776 | 2233 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
2234 | retval = -EFAULT; |
2235 | b--; | |
2236 | break; | |
2237 | } | |
2238 | nr--; | |
2239 | } | |
2240 | ||
53c5ee2c | 2241 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2242 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
40d5e090 PH |
2243 | if (retval == -EAGAIN) { |
2244 | retval = 0; | |
2245 | continue; | |
2246 | } else if (retval) | |
1da177e4 LT |
2247 | break; |
2248 | } else { | |
2249 | int uncopied; | |
04f378b1 AC |
2250 | /* The copy function takes the read lock and handles |
2251 | locking internally for this case */ | |
1da177e4 LT |
2252 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2253 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2254 | if (uncopied) { | |
2255 | retval = -EFAULT; | |
2256 | break; | |
2257 | } | |
2258 | } | |
2259 | ||
6367ca72 | 2260 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2261 | |
2262 | if (b - buf >= minimum) | |
2263 | break; | |
2264 | if (time) | |
2265 | timeout = time; | |
2266 | } | |
42458f41 PH |
2267 | n_tty_set_room(tty); |
2268 | up_read(&tty->termios_rwsem); | |
2269 | ||
1da177e4 | 2270 | remove_wait_queue(&tty->read_wait, &wait); |
1da177e4 | 2271 | if (!waitqueue_active(&tty->read_wait)) |
f6c8dbe6 | 2272 | ldata->minimum_to_wake = minimum; |
1da177e4 | 2273 | |
aebf0453 PH |
2274 | mutex_unlock(&ldata->atomic_read_lock); |
2275 | ||
1da177e4 | 2276 | __set_current_state(TASK_RUNNING); |
40d5e090 PH |
2277 | if (b - buf) |
2278 | retval = b - buf; | |
1da177e4 LT |
2279 | |
2280 | return retval; | |
2281 | } | |
2282 | ||
2283 | /** | |
11a96d18 | 2284 | * n_tty_write - write function for tty |
1da177e4 LT |
2285 | * @tty: tty device |
2286 | * @file: file object | |
2287 | * @buf: userspace buffer pointer | |
2288 | * @nr: size of I/O | |
2289 | * | |
a88a69c9 | 2290 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2291 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2292 | * and other such events. Since the receive code will echo characters, |
2293 | * thus calling driver write methods, the output_lock is used in | |
2294 | * the output processing functions called here as well as in the | |
2295 | * echo processing function to protect the column state and space | |
2296 | * left in the buffer. | |
1da177e4 LT |
2297 | * |
2298 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2299 | * |
2300 | * Locking: output_lock to protect column state and space left | |
2301 | * (note that the process_output*() functions take this | |
2302 | * lock themselves) | |
1da177e4 | 2303 | */ |
4edf1827 | 2304 | |
11a96d18 | 2305 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2306 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2307 | { |
2308 | const unsigned char *b = buf; | |
2309 | DECLARE_WAITQUEUE(wait, current); | |
2310 | int c; | |
2311 | ssize_t retval = 0; | |
2312 | ||
2313 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2314 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2315 | retval = tty_check_change(tty); | |
2316 | if (retval) | |
2317 | return retval; | |
2318 | } | |
2319 | ||
9356b535 PH |
2320 | down_read(&tty->termios_rwsem); |
2321 | ||
a88a69c9 JP |
2322 | /* Write out any echoed characters that are still pending */ |
2323 | process_echoes(tty); | |
300a6204 | 2324 | |
1da177e4 LT |
2325 | add_wait_queue(&tty->write_wait, &wait); |
2326 | while (1) { | |
2327 | set_current_state(TASK_INTERRUPTIBLE); | |
2328 | if (signal_pending(current)) { | |
2329 | retval = -ERESTARTSYS; | |
2330 | break; | |
2331 | } | |
2332 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2333 | retval = -EIO; | |
2334 | break; | |
2335 | } | |
582f5590 | 2336 | if (O_OPOST(tty)) { |
1da177e4 | 2337 | while (nr > 0) { |
a88a69c9 | 2338 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2339 | if (num < 0) { |
2340 | if (num == -EAGAIN) | |
2341 | break; | |
2342 | retval = num; | |
2343 | goto break_out; | |
2344 | } | |
2345 | b += num; | |
2346 | nr -= num; | |
2347 | if (nr == 0) | |
2348 | break; | |
2349 | c = *b; | |
a88a69c9 | 2350 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2351 | break; |
2352 | b++; nr--; | |
2353 | } | |
f34d7a5b AC |
2354 | if (tty->ops->flush_chars) |
2355 | tty->ops->flush_chars(tty); | |
1da177e4 | 2356 | } else { |
4291086b PH |
2357 | struct n_tty_data *ldata = tty->disc_data; |
2358 | ||
d6afe27b | 2359 | while (nr > 0) { |
4291086b | 2360 | mutex_lock(&ldata->output_lock); |
f34d7a5b | 2361 | c = tty->ops->write(tty, b, nr); |
4291086b | 2362 | mutex_unlock(&ldata->output_lock); |
d6afe27b RZ |
2363 | if (c < 0) { |
2364 | retval = c; | |
2365 | goto break_out; | |
2366 | } | |
2367 | if (!c) | |
2368 | break; | |
2369 | b += c; | |
2370 | nr -= c; | |
1da177e4 | 2371 | } |
1da177e4 LT |
2372 | } |
2373 | if (!nr) | |
2374 | break; | |
2375 | if (file->f_flags & O_NONBLOCK) { | |
2376 | retval = -EAGAIN; | |
2377 | break; | |
2378 | } | |
9356b535 PH |
2379 | up_read(&tty->termios_rwsem); |
2380 | ||
1da177e4 | 2381 | schedule(); |
9356b535 PH |
2382 | |
2383 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2384 | } |
2385 | break_out: | |
2386 | __set_current_state(TASK_RUNNING); | |
2387 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2388 | if (b - buf != nr && tty->fasync) |
2389 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2390 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2391 | return (b - buf) ? b - buf : retval; |
2392 | } | |
2393 | ||
2394 | /** | |
11a96d18 | 2395 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2396 | * @tty: terminal device |
2397 | * @file: file accessing it | |
2398 | * @wait: poll table | |
2399 | * | |
2400 | * Called when the line discipline is asked to poll() for data or | |
2401 | * for special events. This code is not serialized with respect to | |
2402 | * other events save open/close. | |
2403 | * | |
2404 | * This code must be sure never to sleep through a hangup. | |
2405 | * Called without the kernel lock held - fine | |
1da177e4 | 2406 | */ |
4edf1827 | 2407 | |
11a96d18 | 2408 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2409 | poll_table *wait) |
1da177e4 | 2410 | { |
f6c8dbe6 | 2411 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2412 | unsigned int mask = 0; |
2413 | ||
2414 | poll_wait(file, &tty->read_wait, wait); | |
2415 | poll_wait(file, &tty->write_wait, wait); | |
eafbe67f | 2416 | if (input_available_p(tty, 1)) |
1da177e4 LT |
2417 | mask |= POLLIN | POLLRDNORM; |
2418 | if (tty->packet && tty->link->ctrl_status) | |
2419 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2420 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2421 | mask |= POLLHUP; | |
2422 | if (tty_hung_up_p(file)) | |
2423 | mask |= POLLHUP; | |
2424 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2425 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2426 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2427 | else |
f6c8dbe6 | 2428 | ldata->minimum_to_wake = 1; |
1da177e4 | 2429 | } |
f34d7a5b AC |
2430 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2431 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2432 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2433 | mask |= POLLOUT | POLLWRNORM; |
2434 | return mask; | |
2435 | } | |
2436 | ||
57c94121 | 2437 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2438 | { |
bc5a5e3f | 2439 | size_t nr, head, tail; |
47afa7a5 | 2440 | |
a73d3d69 | 2441 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2442 | return 0; |
ba2e68ac JS |
2443 | head = ldata->canon_head; |
2444 | tail = ldata->read_tail; | |
bc5a5e3f | 2445 | nr = head - tail; |
47afa7a5 AC |
2446 | /* Skip EOF-chars.. */ |
2447 | while (head != tail) { | |
bc5a5e3f PH |
2448 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2449 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2450 | nr--; |
bc5a5e3f | 2451 | tail++; |
47afa7a5 AC |
2452 | } |
2453 | return nr; | |
2454 | } | |
2455 | ||
2456 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2457 | unsigned int cmd, unsigned long arg) | |
2458 | { | |
ba2e68ac | 2459 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2460 | int retval; |
2461 | ||
2462 | switch (cmd) { | |
2463 | case TIOCOUTQ: | |
2464 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2465 | case TIOCINQ: | |
6d76bd26 | 2466 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2467 | if (L_ICANON(tty)) |
57c94121 | 2468 | retval = inq_canon(ldata); |
6d76bd26 PH |
2469 | else |
2470 | retval = read_cnt(ldata); | |
2471 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2472 | return put_user(retval, (unsigned int __user *) arg); |
2473 | default: | |
2474 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2475 | } | |
2476 | } | |
2477 | ||
f6c8dbe6 PH |
2478 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2479 | { | |
2480 | struct n_tty_data *ldata = tty->disc_data; | |
2481 | ||
2482 | if (!waitqueue_active(&tty->read_wait)) { | |
2483 | if (on) | |
2484 | ldata->minimum_to_wake = 1; | |
2485 | else if (!tty->fasync) | |
2486 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2487 | } | |
2488 | } | |
2489 | ||
a352def2 | 2490 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2491 | .magic = TTY_LDISC_MAGIC, |
2492 | .name = "n_tty", | |
2493 | .open = n_tty_open, | |
2494 | .close = n_tty_close, | |
2495 | .flush_buffer = n_tty_flush_buffer, | |
2496 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2497 | .read = n_tty_read, |
2498 | .write = n_tty_write, | |
e10cc1df PF |
2499 | .ioctl = n_tty_ioctl, |
2500 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2501 | .poll = n_tty_poll, |
e10cc1df | 2502 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2503 | .write_wakeup = n_tty_write_wakeup, |
2504 | .fasync = n_tty_fasync, | |
24a89d1c | 2505 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2506 | }; |
572b9adb RG |
2507 | |
2508 | /** | |
2509 | * n_tty_inherit_ops - inherit N_TTY methods | |
2510 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2511 | * | |
593fb1ae | 2512 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2513 | * methods. |
2514 | */ | |
2515 | ||
2516 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2517 | { | |
2518 | *ops = tty_ldisc_N_TTY; | |
2519 | ops->owner = NULL; | |
2520 | ops->refcount = ops->flags = 0; | |
2521 | } | |
2522 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |