Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * n_tty.c --- implements the N_TTY line discipline. | |
4edf1827 | 3 | * |
1da177e4 LT |
4 | * This code used to be in tty_io.c, but things are getting hairy |
5 | * enough that it made sense to split things off. (The N_TTY | |
6 | * processing has changed so much that it's hardly recognizable, | |
7 | * anyway...) | |
8 | * | |
9 | * Note that the open routine for N_TTY is guaranteed never to return | |
10 | * an error. This is because Linux will fall back to setting a line | |
4edf1827 | 11 | * to N_TTY if it can not switch to any other line discipline. |
1da177e4 LT |
12 | * |
13 | * Written by Theodore Ts'o, Copyright 1994. | |
4edf1827 | 14 | * |
1da177e4 LT |
15 | * This file also contains code originally written by Linus Torvalds, |
16 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. | |
4edf1827 | 17 | * |
1da177e4 LT |
18 | * This file may be redistributed under the terms of the GNU General Public |
19 | * License. | |
20 | * | |
21 | * Reduced memory usage for older ARM systems - Russell King. | |
22 | * | |
4edf1827 | 23 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
1da177e4 LT |
24 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
25 | * who actually finally proved there really was a race. | |
26 | * | |
27 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to | |
28 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. | |
11a96d18 | 29 | * Also fixed a bug in BLOCKING mode where n_tty_write returns |
1da177e4 LT |
30 | * EAGAIN |
31 | */ | |
32 | ||
33 | #include <linux/types.h> | |
34 | #include <linux/major.h> | |
35 | #include <linux/errno.h> | |
36 | #include <linux/signal.h> | |
37 | #include <linux/fcntl.h> | |
38 | #include <linux/sched.h> | |
39 | #include <linux/interrupt.h> | |
40 | #include <linux/tty.h> | |
41 | #include <linux/timer.h> | |
42 | #include <linux/ctype.h> | |
43 | #include <linux/mm.h> | |
44 | #include <linux/string.h> | |
45 | #include <linux/slab.h> | |
46 | #include <linux/poll.h> | |
47 | #include <linux/bitops.h> | |
522ed776 MT |
48 | #include <linux/audit.h> |
49 | #include <linux/file.h> | |
300a6204 | 50 | #include <linux/uaccess.h> |
572b9adb | 51 | #include <linux/module.h> |
593fb1ae | 52 | #include <linux/ratelimit.h> |
86e35aea | 53 | #include <linux/vmalloc.h> |
1da177e4 | 54 | |
1da177e4 LT |
55 | |
56 | /* number of characters left in xmit buffer before select has we have room */ | |
57 | #define WAKEUP_CHARS 256 | |
58 | ||
59 | /* | |
60 | * This defines the low- and high-watermarks for throttling and | |
61 | * unthrottling the TTY driver. These watermarks are used for | |
62 | * controlling the space in the read buffer. | |
63 | */ | |
64 | #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ | |
bbd20759 | 65 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
1da177e4 | 66 | |
a88a69c9 JP |
67 | /* |
68 | * Special byte codes used in the echo buffer to represent operations | |
69 | * or special handling of characters. Bytes in the echo buffer that | |
70 | * are not part of such special blocks are treated as normal character | |
71 | * codes. | |
72 | */ | |
73 | #define ECHO_OP_START 0xff | |
74 | #define ECHO_OP_MOVE_BACK_COL 0x80 | |
75 | #define ECHO_OP_SET_CANON_COL 0x81 | |
76 | #define ECHO_OP_ERASE_TAB 0x82 | |
77 | ||
cbfd0340 PH |
78 | #define ECHO_COMMIT_WATERMARK 256 |
79 | #define ECHO_BLOCK 256 | |
80 | #define ECHO_DISCARD_WATERMARK N_TTY_BUF_SIZE - (ECHO_BLOCK + 32) | |
81 | ||
82 | ||
32f13521 PH |
83 | #undef N_TTY_TRACE |
84 | #ifdef N_TTY_TRACE | |
85 | # define n_tty_trace(f, args...) trace_printk(f, ##args) | |
86 | #else | |
87 | # define n_tty_trace(f, args...) | |
88 | #endif | |
89 | ||
70ece7a7 | 90 | struct n_tty_data { |
fb7aa03d PH |
91 | /* producer-published */ |
92 | size_t read_head; | |
70aca71f | 93 | size_t commit_head; |
fb7aa03d | 94 | size_t canon_head; |
9dfd16dd PH |
95 | size_t echo_head; |
96 | size_t echo_commit; | |
1075a6e2 | 97 | size_t echo_mark; |
1bb9d562 | 98 | DECLARE_BITMAP(char_map, 256); |
fb7aa03d PH |
99 | |
100 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c JS |
101 | unsigned long overrun_time; |
102 | int num_overrun; | |
103 | ||
24a89d1c PH |
104 | /* non-atomic */ |
105 | bool no_room; | |
106 | ||
fb7aa03d | 107 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c | 108 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
4d0ed182 | 109 | unsigned char push:1; |
3fe780b3 | 110 | |
fb7aa03d | 111 | /* shared by producer and consumer */ |
20bafb3d | 112 | char read_buf[N_TTY_BUF_SIZE]; |
3fe780b3 | 113 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
20bafb3d | 114 | unsigned char echo_buf[N_TTY_BUF_SIZE]; |
ba2e68ac | 115 | |
f6c8dbe6 | 116 | int minimum_to_wake; |
ba2e68ac | 117 | |
fb7aa03d PH |
118 | /* consumer-published */ |
119 | size_t read_tail; | |
40d5e090 | 120 | size_t line_start; |
fb7aa03d | 121 | |
fb7aa03d PH |
122 | /* protected by output lock */ |
123 | unsigned int column; | |
ba2e68ac | 124 | unsigned int canon_column; |
9dfd16dd | 125 | size_t echo_tail; |
bddc7152 JS |
126 | |
127 | struct mutex atomic_read_lock; | |
128 | struct mutex output_lock; | |
70ece7a7 JS |
129 | }; |
130 | ||
ce74117a PH |
131 | static inline size_t read_cnt(struct n_tty_data *ldata) |
132 | { | |
a2f73be8 | 133 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
134 | } |
135 | ||
bc5a5e3f PH |
136 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
137 | { | |
138 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
139 | } | |
140 | ||
141 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
142 | { | |
143 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
144 | } | |
145 | ||
addaebcc PH |
146 | static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) |
147 | { | |
148 | return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
149 | } | |
150 | ||
151 | static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) | |
152 | { | |
153 | return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
154 | } | |
155 | ||
679e7c29 PH |
156 | static int tty_copy_to_user(struct tty_struct *tty, void __user *to, |
157 | size_t tail, size_t n) | |
72586c60 LA |
158 | { |
159 | struct n_tty_data *ldata = tty->disc_data; | |
679e7c29 PH |
160 | size_t size = N_TTY_BUF_SIZE - tail; |
161 | const void *from = read_buf_addr(ldata, tail); | |
162 | int uncopied; | |
163 | ||
164 | if (n > size) { | |
165 | tty_audit_add_data(tty, from, size, ldata->icanon); | |
166 | uncopied = copy_to_user(to, from, size); | |
167 | if (uncopied) | |
168 | return uncopied; | |
169 | to += size; | |
170 | n -= size; | |
171 | from = ldata->read_buf; | |
172 | } | |
72586c60 | 173 | |
6b2a3d62 | 174 | tty_audit_add_data(tty, from, n, ldata->icanon); |
72586c60 LA |
175 | return copy_to_user(to, from, n); |
176 | } | |
177 | ||
24a89d1c | 178 | /** |
2c5dc464 | 179 | * n_tty_kick_worker - start input worker (if required) |
24a89d1c PH |
180 | * @tty: terminal |
181 | * | |
2c5dc464 | 182 | * Re-schedules the flip buffer work if it may have stopped |
24a89d1c | 183 | * |
6d76bd26 PH |
184 | * Caller holds exclusive termios_rwsem |
185 | * or | |
186 | * n_tty_read()/consumer path: | |
187 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
188 | */ |
189 | ||
2c5dc464 | 190 | static void n_tty_kick_worker(struct tty_struct *tty) |
7879a9f9 | 191 | { |
24a89d1c PH |
192 | struct n_tty_data *ldata = tty->disc_data; |
193 | ||
2c5dc464 PH |
194 | /* Did the input worker stop? Restart it */ |
195 | if (unlikely(ldata->no_room)) { | |
24a89d1c PH |
196 | ldata->no_room = 0; |
197 | ||
ecbbfd44 | 198 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 199 | "scheduling with invalid itty\n"); |
21622939 PH |
200 | /* see if ldisc has been killed - if so, this means that |
201 | * even though the ldisc has been halted and ->buf.work | |
202 | * cancelled, ->buf.work is about to be rescheduled | |
203 | */ | |
204 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
205 | "scheduling buffer work for halted ldisc\n"); | |
e176058f | 206 | tty_buffer_restart_work(tty->port); |
ecbbfd44 | 207 | } |
55db4c64 LT |
208 | } |
209 | ||
9a4aec2d PH |
210 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
211 | { | |
212 | struct n_tty_data *ldata = tty->disc_data; | |
213 | ssize_t n = 0; | |
214 | ||
215 | if (!ldata->icanon) | |
70aca71f | 216 | n = ldata->commit_head - ldata->read_tail; |
9a4aec2d PH |
217 | else |
218 | n = ldata->canon_head - ldata->read_tail; | |
219 | return n; | |
220 | } | |
221 | ||
ee0bab83 PH |
222 | /** |
223 | * n_tty_write_wakeup - asynchronous I/O notifier | |
224 | * @tty: tty device | |
225 | * | |
226 | * Required for the ptys, serial driver etc. since processes | |
227 | * that attach themselves to the master and rely on ASYNC | |
228 | * IO must be woken up | |
229 | */ | |
230 | ||
231 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
232 | { | |
233 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) | |
234 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
235 | } | |
236 | ||
4a23a4df | 237 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 238 | { |
a342846f PH |
239 | struct n_tty_data *ldata = tty->disc_data; |
240 | ||
6367ca72 PH |
241 | /* |
242 | * Check the remaining room for the input canonicalization | |
243 | * mode. We don't want to throttle the driver if we're in | |
244 | * canonical mode and don't have a newline yet! | |
245 | */ | |
a342846f PH |
246 | if (ldata->icanon && ldata->canon_head == ldata->read_tail) |
247 | return; | |
248 | ||
6367ca72 PH |
249 | while (1) { |
250 | int throttled; | |
251 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
5e28cca1 | 252 | if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE) |
6367ca72 PH |
253 | break; |
254 | throttled = tty_throttle_safe(tty); | |
255 | if (!throttled) | |
256 | break; | |
257 | } | |
258 | __tty_set_flow_change(tty, 0); | |
259 | } | |
260 | ||
4b293492 | 261 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 262 | { |
6d27a63c | 263 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { |
3afb1b39 PH |
264 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) |
265 | return; | |
266 | if (!tty->count) | |
267 | return; | |
2c5dc464 | 268 | n_tty_kick_worker(tty); |
6d27a63c | 269 | tty_wakeup(tty->link); |
3afb1b39 PH |
270 | return; |
271 | } | |
272 | ||
6367ca72 PH |
273 | /* If there is enough space in the read buffer now, let the |
274 | * low-level driver know. We use chars_in_buffer() to | |
275 | * check the buffer, as it now knows about canonical mode. | |
276 | * Otherwise, if the driver is throttled and the line is | |
277 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
278 | * we won't get any more characters. | |
279 | */ | |
280 | ||
281 | while (1) { | |
282 | int unthrottled; | |
283 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
284 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
285 | break; | |
286 | if (!tty->count) | |
287 | break; | |
2c5dc464 | 288 | n_tty_kick_worker(tty); |
6367ca72 PH |
289 | unthrottled = tty_unthrottle_safe(tty); |
290 | if (!unthrottled) | |
291 | break; | |
292 | } | |
293 | __tty_set_flow_change(tty, 0); | |
294 | } | |
295 | ||
17b82060 AC |
296 | /** |
297 | * put_tty_queue - add character to tty | |
298 | * @c: character | |
57c94121 | 299 | * @ldata: n_tty data |
17b82060 | 300 | * |
6d76bd26 PH |
301 | * Add a character to the tty read_buf queue. |
302 | * | |
303 | * n_tty_receive_buf()/producer path: | |
304 | * caller holds non-exclusive termios_rwsem | |
17b82060 AC |
305 | */ |
306 | ||
19e2ad6a | 307 | static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 308 | { |
8bfbe2de CR |
309 | *read_buf_addr(ldata, ldata->read_head) = c; |
310 | ldata->read_head++; | |
1da177e4 LT |
311 | } |
312 | ||
1da177e4 LT |
313 | /** |
314 | * reset_buffer_flags - reset buffer state | |
315 | * @tty: terminal to reset | |
316 | * | |
25518c68 PH |
317 | * Reset the read buffer counters and clear the flags. |
318 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 319 | * |
6d76bd26 PH |
320 | * Locking: caller holds exclusive termios_rwsem |
321 | * (or locking is not required) | |
1da177e4 | 322 | */ |
a88a69c9 | 323 | |
b66f4fa5 | 324 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 325 | { |
a73d3d69 | 326 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 327 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
70aca71f | 328 | ldata->commit_head = 0; |
1075a6e2 | 329 | ldata->echo_mark = 0; |
40d5e090 | 330 | ldata->line_start = 0; |
a88a69c9 | 331 | |
a73d3d69 | 332 | ldata->erasing = 0; |
3fe780b3 | 333 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 | 334 | ldata->push = 0; |
1da177e4 LT |
335 | } |
336 | ||
a30737ab PH |
337 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
338 | { | |
339 | unsigned long flags; | |
340 | ||
a30737ab | 341 | if (tty->link->packet) { |
54e8e5fc | 342 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
a30737ab | 343 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; |
54e8e5fc | 344 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
e81107d4 | 345 | wake_up_interruptible(&tty->link->read_wait); |
a30737ab | 346 | } |
a30737ab PH |
347 | } |
348 | ||
1da177e4 LT |
349 | /** |
350 | * n_tty_flush_buffer - clean input queue | |
351 | * @tty: terminal device | |
352 | * | |
25518c68 PH |
353 | * Flush the input buffer. Called when the tty layer wants the |
354 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
355 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 356 | * |
6d76bd26 PH |
357 | * Holds termios_rwsem to exclude producer/consumer while |
358 | * buffer indices are reset. | |
359 | * | |
360 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 361 | */ |
4edf1827 AC |
362 | |
363 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 364 | { |
6d76bd26 | 365 | down_write(&tty->termios_rwsem); |
b66f4fa5 | 366 | reset_buffer_flags(tty->disc_data); |
2c5dc464 | 367 | n_tty_kick_worker(tty); |
4edf1827 | 368 | |
a30737ab PH |
369 | if (tty->link) |
370 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 371 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
372 | } |
373 | ||
1da177e4 LT |
374 | /** |
375 | * is_utf8_continuation - utf8 multibyte check | |
376 | * @c: byte to check | |
377 | * | |
378 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
379 | * character. We use this to correctly compute the on screen size | |
380 | * of the character when printing | |
381 | */ | |
4edf1827 | 382 | |
1da177e4 LT |
383 | static inline int is_utf8_continuation(unsigned char c) |
384 | { | |
385 | return (c & 0xc0) == 0x80; | |
386 | } | |
387 | ||
388 | /** | |
389 | * is_continuation - multibyte check | |
390 | * @c: byte to check | |
391 | * | |
392 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
393 | * character and the terminal is in unicode mode. | |
394 | */ | |
4edf1827 | 395 | |
1da177e4 LT |
396 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
397 | { | |
398 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
399 | } | |
400 | ||
401 | /** | |
a88a69c9 | 402 | * do_output_char - output one character |
1da177e4 LT |
403 | * @c: character (or partial unicode symbol) |
404 | * @tty: terminal device | |
a88a69c9 | 405 | * @space: space available in tty driver write buffer |
1da177e4 | 406 | * |
a88a69c9 JP |
407 | * This is a helper function that handles one output character |
408 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
409 | * doing OPOST processing and putting the results in the |
410 | * tty driver's write buffer. | |
a88a69c9 JP |
411 | * |
412 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
413 | * and NLDLY. They simply aren't relevant in the world today. | |
414 | * If you ever need them, add them here. | |
1da177e4 | 415 | * |
a88a69c9 JP |
416 | * Returns the number of bytes of buffer space used or -1 if |
417 | * no space left. | |
418 | * | |
419 | * Locking: should be called under the output_lock to protect | |
420 | * the column state and space left in the buffer | |
1da177e4 | 421 | */ |
4edf1827 | 422 | |
a88a69c9 | 423 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 424 | { |
53c5ee2c | 425 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 426 | int spaces; |
1da177e4 | 427 | |
1da177e4 LT |
428 | if (!space) |
429 | return -1; | |
300a6204 | 430 | |
a88a69c9 JP |
431 | switch (c) { |
432 | case '\n': | |
433 | if (O_ONLRET(tty)) | |
53c5ee2c | 434 | ldata->column = 0; |
a88a69c9 JP |
435 | if (O_ONLCR(tty)) { |
436 | if (space < 2) | |
437 | return -1; | |
ba2e68ac | 438 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 439 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
440 | return 2; |
441 | } | |
ba2e68ac | 442 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
443 | break; |
444 | case '\r': | |
53c5ee2c | 445 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
446 | return 0; |
447 | if (O_OCRNL(tty)) { | |
448 | c = '\n'; | |
449 | if (O_ONLRET(tty)) | |
ba2e68ac | 450 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 451 | break; |
a88a69c9 | 452 | } |
ba2e68ac | 453 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
454 | break; |
455 | case '\t': | |
53c5ee2c | 456 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
457 | if (O_TABDLY(tty) == XTABS) { |
458 | if (space < spaces) | |
459 | return -1; | |
53c5ee2c | 460 | ldata->column += spaces; |
a88a69c9 JP |
461 | tty->ops->write(tty, " ", spaces); |
462 | return spaces; | |
1da177e4 | 463 | } |
53c5ee2c | 464 | ldata->column += spaces; |
a88a69c9 JP |
465 | break; |
466 | case '\b': | |
53c5ee2c JS |
467 | if (ldata->column > 0) |
468 | ldata->column--; | |
a88a69c9 JP |
469 | break; |
470 | default: | |
a59c0d6f JP |
471 | if (!iscntrl(c)) { |
472 | if (O_OLCUC(tty)) | |
473 | c = toupper(c); | |
474 | if (!is_continuation(c, tty)) | |
53c5ee2c | 475 | ldata->column++; |
a59c0d6f | 476 | } |
a88a69c9 | 477 | break; |
1da177e4 | 478 | } |
a88a69c9 | 479 | |
f34d7a5b | 480 | tty_put_char(tty, c); |
a88a69c9 JP |
481 | return 1; |
482 | } | |
483 | ||
484 | /** | |
485 | * process_output - output post processor | |
486 | * @c: character (or partial unicode symbol) | |
487 | * @tty: terminal device | |
488 | * | |
ee5aa7b8 JP |
489 | * Output one character with OPOST processing. |
490 | * Returns -1 when the output device is full and the character | |
491 | * must be retried. | |
a88a69c9 JP |
492 | * |
493 | * Locking: output_lock to protect column state and space left | |
494 | * (also, this is called from n_tty_write under the | |
495 | * tty layer write lock) | |
496 | */ | |
497 | ||
498 | static int process_output(unsigned char c, struct tty_struct *tty) | |
499 | { | |
bddc7152 | 500 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
501 | int space, retval; |
502 | ||
bddc7152 | 503 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
504 | |
505 | space = tty_write_room(tty); | |
506 | retval = do_output_char(c, tty, space); | |
507 | ||
bddc7152 | 508 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
509 | if (retval < 0) |
510 | return -1; | |
511 | else | |
512 | return 0; | |
1da177e4 LT |
513 | } |
514 | ||
515 | /** | |
a88a69c9 | 516 | * process_output_block - block post processor |
1da177e4 | 517 | * @tty: terminal device |
ee5aa7b8 JP |
518 | * @buf: character buffer |
519 | * @nr: number of bytes to output | |
520 | * | |
521 | * Output a block of characters with OPOST processing. | |
522 | * Returns the number of characters output. | |
1da177e4 LT |
523 | * |
524 | * This path is used to speed up block console writes, among other | |
525 | * things when processing blocks of output data. It handles only | |
526 | * the simple cases normally found and helps to generate blocks of | |
527 | * symbols for the console driver and thus improve performance. | |
528 | * | |
a88a69c9 JP |
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) | |
1da177e4 | 532 | */ |
4edf1827 | 533 | |
a88a69c9 JP |
534 | static ssize_t process_output_block(struct tty_struct *tty, |
535 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 536 | { |
53c5ee2c | 537 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 538 | int space; |
bbd20759 | 539 | int i; |
1da177e4 LT |
540 | const unsigned char *cp; |
541 | ||
bddc7152 | 542 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 543 | |
f34d7a5b | 544 | space = tty_write_room(tty); |
300a6204 | 545 | if (!space) { |
bddc7152 | 546 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 547 | return 0; |
a88a69c9 | 548 | } |
1da177e4 LT |
549 | if (nr > space) |
550 | nr = space; | |
551 | ||
552 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
553 | unsigned char c = *cp; |
554 | ||
555 | switch (c) { | |
1da177e4 LT |
556 | case '\n': |
557 | if (O_ONLRET(tty)) | |
53c5ee2c | 558 | ldata->column = 0; |
1da177e4 LT |
559 | if (O_ONLCR(tty)) |
560 | goto break_out; | |
ba2e68ac | 561 | ldata->canon_column = ldata->column; |
1da177e4 LT |
562 | break; |
563 | case '\r': | |
53c5ee2c | 564 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
565 | goto break_out; |
566 | if (O_OCRNL(tty)) | |
567 | goto break_out; | |
ba2e68ac | 568 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
569 | break; |
570 | case '\t': | |
571 | goto break_out; | |
572 | case '\b': | |
53c5ee2c JS |
573 | if (ldata->column > 0) |
574 | ldata->column--; | |
1da177e4 LT |
575 | break; |
576 | default: | |
a59c0d6f JP |
577 | if (!iscntrl(c)) { |
578 | if (O_OLCUC(tty)) | |
579 | goto break_out; | |
580 | if (!is_continuation(c, tty)) | |
53c5ee2c | 581 | ldata->column++; |
a59c0d6f | 582 | } |
1da177e4 LT |
583 | break; |
584 | } | |
585 | } | |
586 | break_out: | |
f34d7a5b | 587 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 588 | |
bddc7152 | 589 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
590 | return i; |
591 | } | |
592 | ||
a88a69c9 JP |
593 | /** |
594 | * process_echoes - write pending echo characters | |
595 | * @tty: terminal device | |
596 | * | |
597 | * Write previously buffered echo (and other ldisc-generated) | |
598 | * characters to the tty. | |
599 | * | |
600 | * Characters generated by the ldisc (including echoes) need to | |
601 | * be buffered because the driver's write buffer can fill during | |
602 | * heavy program output. Echoing straight to the driver will | |
603 | * often fail under these conditions, causing lost characters and | |
604 | * resulting mismatches of ldisc state information. | |
605 | * | |
606 | * Since the ldisc state must represent the characters actually sent | |
607 | * to the driver at the time of the write, operations like certain | |
608 | * changes in column state are also saved in the buffer and executed | |
609 | * here. | |
610 | * | |
611 | * A circular fifo buffer is used so that the most recent characters | |
612 | * are prioritized. Also, when control characters are echoed with a | |
613 | * prefixed "^", the pair is treated atomically and thus not separated. | |
614 | * | |
019ebdf9 | 615 | * Locking: callers must hold output_lock |
a88a69c9 JP |
616 | */ |
617 | ||
bc5b1ec5 | 618 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 619 | { |
53c5ee2c | 620 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 621 | int space, old_space; |
addaebcc | 622 | size_t tail; |
a88a69c9 | 623 | unsigned char c; |
a88a69c9 | 624 | |
bc5b1ec5 | 625 | old_space = space = tty_write_room(tty); |
a88a69c9 | 626 | |
addaebcc | 627 | tail = ldata->echo_tail; |
29c7c5ca | 628 | while (ldata->echo_commit != tail) { |
addaebcc | 629 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
630 | if (c == ECHO_OP_START) { |
631 | unsigned char op; | |
a88a69c9 JP |
632 | int no_space_left = 0; |
633 | ||
634 | /* | |
635 | * If the buffer byte is the start of a multi-byte | |
636 | * operation, get the next byte, which is either the | |
637 | * op code or a control character value. | |
638 | */ | |
addaebcc | 639 | op = echo_buf(ldata, tail + 1); |
300a6204 | 640 | |
a88a69c9 JP |
641 | switch (op) { |
642 | unsigned int num_chars, num_bs; | |
643 | ||
644 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 645 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
646 | |
647 | /* | |
648 | * Determine how many columns to go back | |
649 | * in order to erase the tab. | |
650 | * This depends on the number of columns | |
651 | * used by other characters within the tab | |
652 | * area. If this (modulo 8) count is from | |
653 | * the start of input rather than from a | |
654 | * previous tab, we offset by canon column. | |
655 | * Otherwise, tab spacing is normal. | |
656 | */ | |
657 | if (!(num_chars & 0x80)) | |
ba2e68ac | 658 | num_chars += ldata->canon_column; |
a88a69c9 JP |
659 | num_bs = 8 - (num_chars & 7); |
660 | ||
661 | if (num_bs > space) { | |
662 | no_space_left = 1; | |
663 | break; | |
664 | } | |
665 | space -= num_bs; | |
666 | while (num_bs--) { | |
667 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
668 | if (ldata->column > 0) |
669 | ldata->column--; | |
a88a69c9 | 670 | } |
addaebcc | 671 | tail += 3; |
a88a69c9 JP |
672 | break; |
673 | ||
674 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 675 | ldata->canon_column = ldata->column; |
addaebcc | 676 | tail += 2; |
a88a69c9 JP |
677 | break; |
678 | ||
679 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
680 | if (ldata->column > 0) |
681 | ldata->column--; | |
addaebcc | 682 | tail += 2; |
a88a69c9 JP |
683 | break; |
684 | ||
685 | case ECHO_OP_START: | |
686 | /* This is an escaped echo op start code */ | |
687 | if (!space) { | |
688 | no_space_left = 1; | |
689 | break; | |
690 | } | |
691 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 692 | ldata->column++; |
a88a69c9 | 693 | space--; |
addaebcc | 694 | tail += 2; |
a88a69c9 JP |
695 | break; |
696 | ||
697 | default: | |
a88a69c9 | 698 | /* |
62b26358 JP |
699 | * If the op is not a special byte code, |
700 | * it is a ctrl char tagged to be echoed | |
701 | * as "^X" (where X is the letter | |
702 | * representing the control char). | |
703 | * Note that we must ensure there is | |
704 | * enough space for the whole ctrl pair. | |
705 | * | |
a88a69c9 | 706 | */ |
62b26358 JP |
707 | if (space < 2) { |
708 | no_space_left = 1; | |
709 | break; | |
710 | } | |
711 | tty_put_char(tty, '^'); | |
712 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 713 | ldata->column += 2; |
62b26358 | 714 | space -= 2; |
addaebcc | 715 | tail += 2; |
a88a69c9 JP |
716 | } |
717 | ||
718 | if (no_space_left) | |
719 | break; | |
720 | } else { | |
582f5590 | 721 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
722 | int retval = do_output_char(c, tty, space); |
723 | if (retval < 0) | |
724 | break; | |
725 | space -= retval; | |
726 | } else { | |
727 | if (!space) | |
728 | break; | |
729 | tty_put_char(tty, c); | |
730 | space -= 1; | |
731 | } | |
addaebcc | 732 | tail += 1; |
a88a69c9 | 733 | } |
a88a69c9 JP |
734 | } |
735 | ||
cbfd0340 PH |
736 | /* If the echo buffer is nearly full (so that the possibility exists |
737 | * of echo overrun before the next commit), then discard enough | |
738 | * data at the tail to prevent a subsequent overrun */ | |
739 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 740 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 741 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
742 | tail += 3; |
743 | else | |
744 | tail += 2; | |
745 | } else | |
746 | tail++; | |
747 | } | |
748 | ||
addaebcc | 749 | ldata->echo_tail = tail; |
bc5b1ec5 | 750 | return old_space - space; |
019ebdf9 PH |
751 | } |
752 | ||
753 | static void commit_echoes(struct tty_struct *tty) | |
754 | { | |
755 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 756 | size_t nr, old, echoed; |
cbfd0340 PH |
757 | size_t head; |
758 | ||
759 | head = ldata->echo_head; | |
1075a6e2 | 760 | ldata->echo_mark = head; |
cbfd0340 PH |
761 | old = ldata->echo_commit - ldata->echo_tail; |
762 | ||
763 | /* Process committed echoes if the accumulated # of bytes | |
764 | * is over the threshold (and try again each time another | |
765 | * block is accumulated) */ | |
766 | nr = head - ldata->echo_tail; | |
767 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
768 | return; | |
a88a69c9 | 769 | |
019ebdf9 | 770 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 771 | ldata->echo_commit = head; |
bc5b1ec5 | 772 | echoed = __process_echoes(tty); |
bddc7152 | 773 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 774 | |
bc5b1ec5 | 775 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
776 | tty->ops->flush_chars(tty); |
777 | } | |
778 | ||
019ebdf9 | 779 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
780 | { |
781 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 782 | size_t echoed; |
17bd7907 | 783 | |
e2613be5 | 784 | if (ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
785 | return; |
786 | ||
787 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 788 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 789 | echoed = __process_echoes(tty); |
019ebdf9 PH |
790 | mutex_unlock(&ldata->output_lock); |
791 | ||
bc5b1ec5 | 792 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 793 | tty->ops->flush_chars(tty); |
17bd7907 PH |
794 | } |
795 | ||
1075a6e2 | 796 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
797 | static void flush_echoes(struct tty_struct *tty) |
798 | { | |
799 | struct n_tty_data *ldata = tty->disc_data; | |
800 | ||
39434abd PH |
801 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
802 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
803 | return; |
804 | ||
805 | mutex_lock(&ldata->output_lock); | |
806 | ldata->echo_commit = ldata->echo_head; | |
807 | __process_echoes(tty); | |
808 | mutex_unlock(&ldata->output_lock); | |
809 | } | |
810 | ||
a88a69c9 JP |
811 | /** |
812 | * add_echo_byte - add a byte to the echo buffer | |
813 | * @c: unicode byte to echo | |
57c94121 | 814 | * @ldata: n_tty data |
a88a69c9 JP |
815 | * |
816 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
817 | */ |
818 | ||
cbfd0340 | 819 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 820 | { |
addaebcc | 821 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
822 | } |
823 | ||
824 | /** | |
825 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 826 | * @ldata: n_tty data |
a88a69c9 JP |
827 | * |
828 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
829 | */ |
830 | ||
57c94121 | 831 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 832 | { |
57c94121 JS |
833 | add_echo_byte(ECHO_OP_START, ldata); |
834 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
835 | } |
836 | ||
837 | /** | |
838 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 839 | * @ldata: n_tty data |
a88a69c9 JP |
840 | * |
841 | * Add an operation to the echo buffer to set the canon column | |
842 | * to the current column. | |
a88a69c9 JP |
843 | */ |
844 | ||
57c94121 | 845 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 846 | { |
57c94121 JS |
847 | add_echo_byte(ECHO_OP_START, ldata); |
848 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
849 | } |
850 | ||
851 | /** | |
852 | * echo_erase_tab - add operation to erase a tab | |
853 | * @num_chars: number of character columns already used | |
854 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 855 | * @ldata: n_tty data |
a88a69c9 JP |
856 | * |
857 | * Add an operation to the echo buffer to erase a tab. | |
858 | * | |
859 | * Called by the eraser function, which knows how many character | |
860 | * columns have been used since either a previous tab or the start | |
861 | * of input. This information will be used later, along with | |
862 | * canon column (if applicable), to go back the correct number | |
863 | * of columns. | |
a88a69c9 JP |
864 | */ |
865 | ||
866 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 867 | struct n_tty_data *ldata) |
a88a69c9 | 868 | { |
57c94121 JS |
869 | add_echo_byte(ECHO_OP_START, ldata); |
870 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
871 | |
872 | /* We only need to know this modulo 8 (tab spacing) */ | |
873 | num_chars &= 7; | |
874 | ||
875 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
876 | if (after_tab) | |
877 | num_chars |= 0x80; | |
300a6204 | 878 | |
57c94121 | 879 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
880 | } |
881 | ||
882 | /** | |
883 | * echo_char_raw - echo a character raw | |
884 | * @c: unicode byte to echo | |
885 | * @tty: terminal device | |
886 | * | |
887 | * Echo user input back onto the screen. This must be called only when | |
888 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
889 | * | |
890 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
891 | */ |
892 | ||
57c94121 | 893 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 894 | { |
a88a69c9 | 895 | if (c == ECHO_OP_START) { |
57c94121 JS |
896 | add_echo_byte(ECHO_OP_START, ldata); |
897 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 898 | } else { |
57c94121 | 899 | add_echo_byte(c, ldata); |
a88a69c9 | 900 | } |
a88a69c9 | 901 | } |
1da177e4 | 902 | |
1da177e4 | 903 | /** |
a88a69c9 | 904 | * echo_char - echo a character |
1da177e4 LT |
905 | * @c: unicode byte to echo |
906 | * @tty: terminal device | |
907 | * | |
4edf1827 | 908 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 909 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 910 | * |
62b26358 JP |
911 | * This variant tags control characters to be echoed as "^X" |
912 | * (where X is the letter representing the control char). | |
1da177e4 LT |
913 | */ |
914 | ||
915 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
916 | { | |
bddc7152 JS |
917 | struct n_tty_data *ldata = tty->disc_data; |
918 | ||
a88a69c9 | 919 | if (c == ECHO_OP_START) { |
57c94121 JS |
920 | add_echo_byte(ECHO_OP_START, ldata); |
921 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 922 | } else { |
62b26358 | 923 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
924 | add_echo_byte(ECHO_OP_START, ldata); |
925 | add_echo_byte(c, ldata); | |
a88a69c9 | 926 | } |
1da177e4 LT |
927 | } |
928 | ||
17b82060 | 929 | /** |
a88a69c9 | 930 | * finish_erasing - complete erase |
57c94121 | 931 | * @ldata: n_tty data |
17b82060 | 932 | */ |
a88a69c9 | 933 | |
57c94121 | 934 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 935 | { |
53c5ee2c | 936 | if (ldata->erasing) { |
57c94121 | 937 | echo_char_raw('/', ldata); |
53c5ee2c | 938 | ldata->erasing = 0; |
1da177e4 LT |
939 | } |
940 | } | |
941 | ||
942 | /** | |
943 | * eraser - handle erase function | |
944 | * @c: character input | |
945 | * @tty: terminal device | |
946 | * | |
3a4fa0a2 | 947 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
948 | * present in the stream from the driver layer. Handles the complexities |
949 | * of UTF-8 multibyte symbols. | |
17b82060 | 950 | * |
6d76bd26 PH |
951 | * n_tty_receive_buf()/producer path: |
952 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 953 | */ |
4edf1827 | 954 | |
1da177e4 LT |
955 | static void eraser(unsigned char c, struct tty_struct *tty) |
956 | { | |
53c5ee2c | 957 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 958 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
959 | size_t head; |
960 | size_t cnt; | |
961 | int seen_alnums; | |
1da177e4 | 962 | |
ba2e68ac | 963 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 964 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
965 | return; |
966 | } | |
967 | if (c == ERASE_CHAR(tty)) | |
968 | kill_type = ERASE; | |
969 | else if (c == WERASE_CHAR(tty)) | |
970 | kill_type = WERASE; | |
971 | else { | |
972 | if (!L_ECHO(tty)) { | |
ba2e68ac | 973 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
974 | return; |
975 | } | |
976 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 977 | ldata->read_head = ldata->canon_head; |
57c94121 | 978 | finish_erasing(ldata); |
1da177e4 LT |
979 | echo_char(KILL_CHAR(tty), tty); |
980 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
981 | if (L_ECHOK(tty)) | |
57c94121 | 982 | echo_char_raw('\n', ldata); |
1da177e4 LT |
983 | return; |
984 | } | |
985 | kill_type = KILL; | |
986 | } | |
987 | ||
988 | seen_alnums = 0; | |
ba2e68ac JS |
989 | while (ldata->read_head != ldata->canon_head) { |
990 | head = ldata->read_head; | |
1da177e4 LT |
991 | |
992 | /* erase a single possibly multibyte character */ | |
993 | do { | |
bc5a5e3f PH |
994 | head--; |
995 | c = read_buf(ldata, head); | |
ba2e68ac | 996 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
997 | |
998 | /* do not partially erase */ | |
999 | if (is_continuation(c, tty)) | |
1000 | break; | |
1001 | ||
1002 | if (kill_type == WERASE) { | |
1003 | /* Equivalent to BSD's ALTWERASE. */ | |
1004 | if (isalnum(c) || c == '_') | |
1005 | seen_alnums++; | |
1006 | else if (seen_alnums) | |
1007 | break; | |
1008 | } | |
bc5a5e3f | 1009 | cnt = ldata->read_head - head; |
ba2e68ac | 1010 | ldata->read_head = head; |
1da177e4 LT |
1011 | if (L_ECHO(tty)) { |
1012 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1013 | if (!ldata->erasing) { |
57c94121 | 1014 | echo_char_raw('\\', ldata); |
53c5ee2c | 1015 | ldata->erasing = 1; |
1da177e4 LT |
1016 | } |
1017 | /* if cnt > 1, output a multi-byte character */ | |
1018 | echo_char(c, tty); | |
1019 | while (--cnt > 0) { | |
bc5a5e3f PH |
1020 | head++; |
1021 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1022 | echo_move_back_col(ldata); |
1da177e4 LT |
1023 | } |
1024 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1025 | echo_char(ERASE_CHAR(tty), tty); | |
1026 | } else if (c == '\t') { | |
a88a69c9 JP |
1027 | unsigned int num_chars = 0; |
1028 | int after_tab = 0; | |
bc5a5e3f | 1029 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1030 | |
1031 | /* | |
1032 | * Count the columns used for characters | |
1033 | * since the start of input or after a | |
1034 | * previous tab. | |
1035 | * This info is used to go back the correct | |
1036 | * number of columns. | |
1037 | */ | |
ba2e68ac | 1038 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1039 | tail--; |
1040 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1041 | if (c == '\t') { |
1042 | after_tab = 1; | |
1043 | break; | |
300a6204 | 1044 | } else if (iscntrl(c)) { |
1da177e4 | 1045 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1046 | num_chars += 2; |
1047 | } else if (!is_continuation(c, tty)) { | |
1048 | num_chars++; | |
1049 | } | |
1da177e4 | 1050 | } |
57c94121 | 1051 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1052 | } else { |
1053 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1054 | echo_char_raw('\b', ldata); |
1055 | echo_char_raw(' ', ldata); | |
1056 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1057 | } |
1058 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1059 | echo_char_raw('\b', ldata); |
1060 | echo_char_raw(' ', ldata); | |
1061 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1062 | } |
1063 | } | |
1064 | } | |
1065 | if (kill_type == ERASE) | |
1066 | break; | |
1067 | } | |
ba2e68ac | 1068 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1069 | finish_erasing(ldata); |
1da177e4 LT |
1070 | } |
1071 | ||
1072 | /** | |
1073 | * isig - handle the ISIG optio | |
1074 | * @sig: signal | |
1075 | * @tty: terminal | |
1da177e4 | 1076 | * |
8c985d18 PH |
1077 | * Called when a signal is being sent due to terminal input. |
1078 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1079 | * |
d2b6f447 PH |
1080 | * Performs input and output flush if !NOFLSH. In this context, the echo |
1081 | * buffer is 'output'. The signal is processed first to alert any current | |
1082 | * readers or writers to discontinue and exit their i/o loops. | |
1083 | * | |
8c985d18 | 1084 | * Locking: ctrl_lock |
1da177e4 | 1085 | */ |
4edf1827 | 1086 | |
3b19e032 | 1087 | static void __isig(int sig, struct tty_struct *tty) |
1da177e4 | 1088 | { |
8c985d18 PH |
1089 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1090 | if (tty_pgrp) { | |
1091 | kill_pgrp(tty_pgrp, sig, 1); | |
1092 | put_pid(tty_pgrp); | |
1da177e4 | 1093 | } |
3b19e032 | 1094 | } |
d2b6f447 | 1095 | |
3b19e032 PH |
1096 | static void isig(int sig, struct tty_struct *tty) |
1097 | { | |
1098 | struct n_tty_data *ldata = tty->disc_data; | |
1099 | ||
1100 | if (L_NOFLSH(tty)) { | |
1101 | /* signal only */ | |
1102 | __isig(sig, tty); | |
1103 | ||
1104 | } else { /* signal and flush */ | |
d2b6f447 PH |
1105 | up_read(&tty->termios_rwsem); |
1106 | down_write(&tty->termios_rwsem); | |
1107 | ||
3b19e032 PH |
1108 | __isig(sig, tty); |
1109 | ||
d2b6f447 PH |
1110 | /* clear echo buffer */ |
1111 | mutex_lock(&ldata->output_lock); | |
1112 | ldata->echo_head = ldata->echo_tail = 0; | |
1113 | ldata->echo_mark = ldata->echo_commit = 0; | |
1114 | mutex_unlock(&ldata->output_lock); | |
1115 | ||
1116 | /* clear output buffer */ | |
1117 | tty_driver_flush_buffer(tty); | |
1118 | ||
1119 | /* clear input buffer */ | |
1120 | reset_buffer_flags(tty->disc_data); | |
1121 | ||
1122 | /* notify pty master of flush */ | |
1123 | if (tty->link) | |
1124 | n_tty_packet_mode_flush(tty); | |
1125 | ||
1126 | up_write(&tty->termios_rwsem); | |
1127 | down_read(&tty->termios_rwsem); | |
1128 | } | |
1da177e4 LT |
1129 | } |
1130 | ||
1131 | /** | |
1132 | * n_tty_receive_break - handle break | |
1133 | * @tty: terminal | |
1134 | * | |
1135 | * An RS232 break event has been hit in the incoming bitstream. This | |
1136 | * can cause a variety of events depending upon the termios settings. | |
1137 | * | |
6d76bd26 PH |
1138 | * n_tty_receive_buf()/producer path: |
1139 | * caller holds non-exclusive termios_rwsem | |
6d76bd26 PH |
1140 | * |
1141 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1142 | */ |
4edf1827 | 1143 | |
4b293492 | 1144 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1145 | { |
57c94121 JS |
1146 | struct n_tty_data *ldata = tty->disc_data; |
1147 | ||
1da177e4 LT |
1148 | if (I_IGNBRK(tty)) |
1149 | return; | |
1150 | if (I_BRKINT(tty)) { | |
8c985d18 | 1151 | isig(SIGINT, tty); |
1da177e4 LT |
1152 | return; |
1153 | } | |
1154 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1155 | put_tty_queue('\377', ldata); |
1156 | put_tty_queue('\0', ldata); | |
1da177e4 | 1157 | } |
57c94121 | 1158 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1159 | } |
1160 | ||
1161 | /** | |
1162 | * n_tty_receive_overrun - handle overrun reporting | |
1163 | * @tty: terminal | |
1164 | * | |
1165 | * Data arrived faster than we could process it. While the tty | |
1166 | * driver has flagged this the bits that were missed are gone | |
1167 | * forever. | |
1168 | * | |
1169 | * Called from the receive_buf path so single threaded. Does not | |
1170 | * need locking as num_overrun and overrun_time are function | |
1171 | * private. | |
1172 | */ | |
4edf1827 | 1173 | |
4b293492 | 1174 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1175 | { |
53c5ee2c | 1176 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1177 | |
53c5ee2c JS |
1178 | ldata->num_overrun++; |
1179 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1180 | time_after(ldata->overrun_time, jiffies)) { | |
339f36ba | 1181 | tty_warn(tty, "%d input overrun(s)\n", ldata->num_overrun); |
53c5ee2c JS |
1182 | ldata->overrun_time = jiffies; |
1183 | ldata->num_overrun = 0; | |
1da177e4 LT |
1184 | } |
1185 | } | |
1186 | ||
1187 | /** | |
1188 | * n_tty_receive_parity_error - error notifier | |
1189 | * @tty: terminal device | |
1190 | * @c: character | |
1191 | * | |
1192 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1193 | * the error case if necessary. |
1194 | * | |
1195 | * n_tty_receive_buf()/producer path: | |
1196 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 1197 | */ |
4b293492 | 1198 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1199 | { |
57c94121 JS |
1200 | struct n_tty_data *ldata = tty->disc_data; |
1201 | ||
66528f90 PH |
1202 | if (I_INPCK(tty)) { |
1203 | if (I_IGNPAR(tty)) | |
1204 | return; | |
1205 | if (I_PARMRK(tty)) { | |
1206 | put_tty_queue('\377', ldata); | |
1207 | put_tty_queue('\0', ldata); | |
1208 | put_tty_queue(c, ldata); | |
1209 | } else | |
1210 | put_tty_queue('\0', ldata); | |
1211 | } else | |
57c94121 | 1212 | put_tty_queue(c, ldata); |
1da177e4 LT |
1213 | } |
1214 | ||
b0ac50be PH |
1215 | static void |
1216 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1217 | { | |
d2b6f447 | 1218 | isig(signal, tty); |
b0ac50be PH |
1219 | if (I_IXON(tty)) |
1220 | start_tty(tty); | |
1221 | if (L_ECHO(tty)) { | |
1222 | echo_char(c, tty); | |
1223 | commit_echoes(tty); | |
e2613be5 PH |
1224 | } else |
1225 | process_echoes(tty); | |
b0ac50be PH |
1226 | return; |
1227 | } | |
1228 | ||
1da177e4 LT |
1229 | /** |
1230 | * n_tty_receive_char - perform processing | |
1231 | * @tty: terminal device | |
1232 | * @c: character | |
1233 | * | |
1234 | * Process an individual character of input received from the driver. | |
4edf1827 | 1235 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1236 | * driver above. |
6d76bd26 PH |
1237 | * |
1238 | * n_tty_receive_buf()/producer path: | |
1239 | * caller holds non-exclusive termios_rwsem | |
1240 | * publishes canon_head if canonical mode is active | |
e60d27c4 PH |
1241 | * |
1242 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1243 | */ |
1244 | ||
e60d27c4 | 1245 | static int |
4b1f79c2 | 1246 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1247 | { |
53c5ee2c | 1248 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1249 | |
1da177e4 LT |
1250 | if (I_IXON(tty)) { |
1251 | if (c == START_CHAR(tty)) { | |
1252 | start_tty(tty); | |
e2613be5 | 1253 | process_echoes(tty); |
e60d27c4 | 1254 | return 0; |
1da177e4 LT |
1255 | } |
1256 | if (c == STOP_CHAR(tty)) { | |
1257 | stop_tty(tty); | |
e60d27c4 | 1258 | return 0; |
1da177e4 LT |
1259 | } |
1260 | } | |
575537b3 | 1261 | |
1da177e4 | 1262 | if (L_ISIG(tty)) { |
b0ac50be PH |
1263 | if (c == INTR_CHAR(tty)) { |
1264 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1265 | return 0; |
b0ac50be PH |
1266 | } else if (c == QUIT_CHAR(tty)) { |
1267 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1268 | return 0; |
b0ac50be PH |
1269 | } else if (c == SUSP_CHAR(tty)) { |
1270 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1271 | return 0; |
1da177e4 LT |
1272 | } |
1273 | } | |
575537b3 | 1274 | |
855df3c0 PH |
1275 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1276 | start_tty(tty); | |
1277 | process_echoes(tty); | |
1278 | } | |
1279 | ||
575537b3 JP |
1280 | if (c == '\r') { |
1281 | if (I_IGNCR(tty)) | |
e60d27c4 | 1282 | return 0; |
575537b3 JP |
1283 | if (I_ICRNL(tty)) |
1284 | c = '\n'; | |
1285 | } else if (c == '\n' && I_INLCR(tty)) | |
1286 | c = '\r'; | |
1287 | ||
53c5ee2c | 1288 | if (ldata->icanon) { |
1da177e4 LT |
1289 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1290 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1291 | eraser(c, tty); | |
17bd7907 | 1292 | commit_echoes(tty); |
e60d27c4 | 1293 | return 0; |
1da177e4 LT |
1294 | } |
1295 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1296 | ldata->lnext = 1; |
1da177e4 | 1297 | if (L_ECHO(tty)) { |
57c94121 | 1298 | finish_erasing(ldata); |
1da177e4 | 1299 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1300 | echo_char_raw('^', ldata); |
1301 | echo_char_raw('\b', ldata); | |
17bd7907 | 1302 | commit_echoes(tty); |
1da177e4 LT |
1303 | } |
1304 | } | |
e60d27c4 | 1305 | return 1; |
1da177e4 | 1306 | } |
e60d27c4 | 1307 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1308 | size_t tail = ldata->canon_head; |
1da177e4 | 1309 | |
57c94121 | 1310 | finish_erasing(ldata); |
1da177e4 | 1311 | echo_char(c, tty); |
57c94121 | 1312 | echo_char_raw('\n', ldata); |
ba2e68ac | 1313 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1314 | echo_char(read_buf(ldata, tail), tty); |
1315 | tail++; | |
1da177e4 | 1316 | } |
17bd7907 | 1317 | commit_echoes(tty); |
e60d27c4 | 1318 | return 0; |
1da177e4 LT |
1319 | } |
1320 | if (c == '\n') { | |
acc71bba | 1321 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1322 | echo_char_raw('\n', ldata); |
17bd7907 | 1323 | commit_echoes(tty); |
1da177e4 LT |
1324 | } |
1325 | goto handle_newline; | |
1326 | } | |
1327 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1328 | c = __DISABLED_CHAR; |
1329 | goto handle_newline; | |
1330 | } | |
1331 | if ((c == EOL_CHAR(tty)) || | |
1332 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1333 | /* | |
1334 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1335 | */ | |
1336 | if (L_ECHO(tty)) { | |
1da177e4 | 1337 | /* Record the column of first canon char. */ |
ba2e68ac | 1338 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1339 | echo_set_canon_col(ldata); |
1da177e4 | 1340 | echo_char(c, tty); |
17bd7907 | 1341 | commit_echoes(tty); |
1da177e4 LT |
1342 | } |
1343 | /* | |
1344 | * XXX does PARMRK doubling happen for | |
1345 | * EOL_CHAR and EOL2_CHAR? | |
1346 | */ | |
001ba923 | 1347 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
57c94121 | 1348 | put_tty_queue(c, ldata); |
1da177e4 | 1349 | |
4edf1827 | 1350 | handle_newline: |
bc5a5e3f | 1351 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1352 | put_tty_queue(c, ldata); |
70aca71f | 1353 | smp_store_release(&ldata->canon_head, ldata->read_head); |
1da177e4 | 1354 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
e81107d4 | 1355 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
e60d27c4 | 1356 | return 0; |
1da177e4 LT |
1357 | } |
1358 | } | |
4edf1827 | 1359 | |
acc71bba | 1360 | if (L_ECHO(tty)) { |
57c94121 | 1361 | finish_erasing(ldata); |
1da177e4 | 1362 | if (c == '\n') |
57c94121 | 1363 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1364 | else { |
1365 | /* Record the column of first canon char. */ | |
ba2e68ac | 1366 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1367 | echo_set_canon_col(ldata); |
1da177e4 LT |
1368 | echo_char(c, tty); |
1369 | } | |
17bd7907 | 1370 | commit_echoes(tty); |
1da177e4 LT |
1371 | } |
1372 | ||
001ba923 PH |
1373 | /* PARMRK doubling check */ |
1374 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
57c94121 | 1375 | put_tty_queue(c, ldata); |
1da177e4 | 1376 | |
57c94121 | 1377 | put_tty_queue(c, ldata); |
e60d27c4 | 1378 | return 0; |
4edf1827 | 1379 | } |
1da177e4 | 1380 | |
e60d27c4 PH |
1381 | static inline void |
1382 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1383 | { |
1384 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1385 | |
e60d27c4 PH |
1386 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1387 | start_tty(tty); | |
1388 | process_echoes(tty); | |
1389 | } | |
1390 | if (L_ECHO(tty)) { | |
1391 | finish_erasing(ldata); | |
1392 | /* Record the column of first canon char. */ | |
1393 | if (ldata->canon_head == ldata->read_head) | |
1394 | echo_set_canon_col(ldata); | |
1395 | echo_char(c, tty); | |
1396 | commit_echoes(tty); | |
4b1f79c2 | 1397 | } |
001ba923 PH |
1398 | /* PARMRK doubling check */ |
1399 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
e60d27c4 PH |
1400 | put_tty_queue(c, ldata); |
1401 | put_tty_queue(c, ldata); | |
1402 | } | |
4b1f79c2 | 1403 | |
eb3e4668 | 1404 | static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
e60d27c4 PH |
1405 | { |
1406 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1407 | } |
1408 | ||
7de971b0 PH |
1409 | static inline void |
1410 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1411 | { | |
1412 | struct n_tty_data *ldata = tty->disc_data; | |
1413 | ||
e60d27c4 PH |
1414 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1415 | start_tty(tty); | |
1416 | process_echoes(tty); | |
7de971b0 | 1417 | } |
e60d27c4 PH |
1418 | if (L_ECHO(tty)) { |
1419 | finish_erasing(ldata); | |
1420 | /* Record the column of first canon char. */ | |
1421 | if (ldata->canon_head == ldata->read_head) | |
1422 | echo_set_canon_col(ldata); | |
1423 | echo_char(c, tty); | |
1424 | commit_echoes(tty); | |
1425 | } | |
1426 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1427 | } |
1428 | ||
8dc4b25d | 1429 | static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) |
ad0cc7ba PH |
1430 | { |
1431 | if (I_ISTRIP(tty)) | |
1432 | c &= 0x7f; | |
1433 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1434 | c = tolower(c); | |
1435 | ||
1436 | if (I_IXON(tty)) { | |
1437 | if (c == STOP_CHAR(tty)) | |
1438 | stop_tty(tty); | |
1439 | else if (c == START_CHAR(tty) || | |
1440 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1441 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1442 | c != SUSP_CHAR(tty))) { | |
1443 | start_tty(tty); | |
1444 | process_echoes(tty); | |
1445 | } | |
1446 | } | |
1447 | } | |
1448 | ||
d2f8d7ab PH |
1449 | static void |
1450 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1451 | { | |
d2f8d7ab PH |
1452 | switch (flag) { |
1453 | case TTY_BREAK: | |
1454 | n_tty_receive_break(tty); | |
1455 | break; | |
1456 | case TTY_PARITY: | |
1457 | case TTY_FRAME: | |
1458 | n_tty_receive_parity_error(tty, c); | |
1459 | break; | |
1460 | case TTY_OVERRUN: | |
1461 | n_tty_receive_overrun(tty); | |
1462 | break; | |
1463 | default: | |
339f36ba | 1464 | tty_err(tty, "unknown flag %d\n", flag); |
d2f8d7ab PH |
1465 | break; |
1466 | } | |
1467 | } | |
1468 | ||
e60d27c4 PH |
1469 | static void |
1470 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1471 | { | |
1472 | struct n_tty_data *ldata = tty->disc_data; | |
1473 | ||
1474 | ldata->lnext = 0; | |
1475 | if (likely(flag == TTY_NORMAL)) { | |
1476 | if (I_ISTRIP(tty)) | |
1477 | c &= 0x7f; | |
1478 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1479 | c = tolower(c); | |
1480 | n_tty_receive_char(tty, c); | |
1481 | } else | |
1482 | n_tty_receive_char_flagged(tty, c, flag); | |
1483 | } | |
1484 | ||
4a23a4df PH |
1485 | static void |
1486 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1487 | char *fp, int count) | |
1488 | { | |
1489 | struct n_tty_data *ldata = tty->disc_data; | |
1490 | size_t n, head; | |
1491 | ||
1492 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1493 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1494 | memcpy(read_buf_addr(ldata, head), cp, n); |
1495 | ldata->read_head += n; | |
1496 | cp += n; | |
1497 | count -= n; | |
1498 | ||
1499 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1500 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1501 | memcpy(read_buf_addr(ldata, head), cp, n); |
1502 | ldata->read_head += n; | |
1503 | } | |
1504 | ||
554117bd PH |
1505 | static void |
1506 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1507 | char *fp, int count) | |
1508 | { | |
1509 | struct n_tty_data *ldata = tty->disc_data; | |
1510 | char flag = TTY_NORMAL; | |
1511 | ||
1512 | while (count--) { | |
1513 | if (fp) | |
1514 | flag = *fp++; | |
1515 | if (likely(flag == TTY_NORMAL)) | |
1516 | put_tty_queue(*cp++, ldata); | |
1517 | else | |
1518 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1519 | } | |
1520 | } | |
1521 | ||
ad0cc7ba PH |
1522 | static void |
1523 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1524 | char *fp, int count) | |
1525 | { | |
1526 | char flag = TTY_NORMAL; | |
1527 | ||
1528 | while (count--) { | |
1529 | if (fp) | |
1530 | flag = *fp++; | |
1531 | if (likely(flag == TTY_NORMAL)) | |
1532 | n_tty_receive_char_closing(tty, *cp++); | |
1533 | else | |
1534 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1535 | } | |
1536 | } | |
1537 | ||
7d88d637 PH |
1538 | static void |
1539 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1540 | char *fp, int count) |
1541 | { | |
1542 | struct n_tty_data *ldata = tty->disc_data; | |
1543 | char flag = TTY_NORMAL; | |
1544 | ||
1545 | while (count--) { | |
1546 | if (fp) | |
1547 | flag = *fp++; | |
1548 | if (likely(flag == TTY_NORMAL)) { | |
1549 | unsigned char c = *cp++; | |
1550 | ||
1551 | if (I_ISTRIP(tty)) | |
1552 | c &= 0x7f; | |
1553 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1554 | c = tolower(c); | |
1555 | if (L_EXTPROC(tty)) { | |
1556 | put_tty_queue(c, ldata); | |
1557 | continue; | |
1558 | } | |
e60d27c4 PH |
1559 | if (!test_bit(c, ldata->char_map)) |
1560 | n_tty_receive_char_inline(tty, c); | |
1561 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1562 | if (fp) | |
1563 | flag = *fp++; | |
1564 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1565 | count--; | |
1566 | } | |
6baad008 PH |
1567 | } else |
1568 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1569 | } | |
1570 | } | |
1571 | ||
1572 | static void | |
1573 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1574 | char *fp, int count) | |
7d88d637 | 1575 | { |
e60d27c4 | 1576 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1577 | char flag = TTY_NORMAL; |
1578 | ||
1579 | while (count--) { | |
1580 | if (fp) | |
1581 | flag = *fp++; | |
e60d27c4 PH |
1582 | if (likely(flag == TTY_NORMAL)) { |
1583 | unsigned char c = *cp++; | |
1584 | ||
1585 | if (!test_bit(c, ldata->char_map)) | |
1586 | n_tty_receive_char_fast(tty, c); | |
1587 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1588 | if (fp) | |
1589 | flag = *fp++; | |
1590 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1591 | count--; | |
1592 | } | |
1593 | } else | |
7d88d637 PH |
1594 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1595 | } | |
1596 | } | |
1597 | ||
24a89d1c PH |
1598 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1599 | char *fp, int count) | |
1da177e4 | 1600 | { |
53c5ee2c | 1601 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1602 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1603 | |
4a23a4df PH |
1604 | if (ldata->real_raw) |
1605 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1606 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1607 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1608 | else if (tty->closing && !L_EXTPROC(tty)) |
1609 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1610 | else { |
e60d27c4 PH |
1611 | if (ldata->lnext) { |
1612 | char flag = TTY_NORMAL; | |
1613 | ||
1614 | if (fp) | |
1615 | flag = *fp++; | |
1616 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1617 | count--; | |
1618 | } | |
1619 | ||
7de971b0 | 1620 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1621 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1622 | else | |
1623 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1624 | |
1625 | flush_echoes(tty); | |
f34d7a5b AC |
1626 | if (tty->ops->flush_chars) |
1627 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1628 | } |
1629 | ||
70aca71f PH |
1630 | if (ldata->icanon && !L_EXTPROC(tty)) |
1631 | return; | |
1632 | ||
1633 | /* publish read_head to consumer */ | |
1634 | smp_store_release(&ldata->commit_head, ldata->read_head); | |
1635 | ||
1636 | if ((read_cnt(ldata) >= ldata->minimum_to_wake) || L_EXTPROC(tty)) { | |
1da177e4 | 1637 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
e81107d4 | 1638 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 | 1639 | } |
1da177e4 LT |
1640 | } |
1641 | ||
fb5ef9e7 PH |
1642 | /** |
1643 | * n_tty_receive_buf_common - process input | |
1644 | * @tty: device to receive input | |
1645 | * @cp: input chars | |
1646 | * @fp: flags for each char (if NULL, all chars are TTY_NORMAL) | |
1647 | * @count: number of input chars in @cp | |
1648 | * | |
1649 | * Called by the terminal driver when a block of characters has | |
1650 | * been received. This function must be called from soft contexts | |
1651 | * not from interrupt context. The driver is responsible for making | |
1652 | * calls one at a time and in order (or using flush_to_ldisc) | |
1653 | * | |
1654 | * Returns the # of input chars from @cp which were processed. | |
1655 | * | |
1656 | * In canonical mode, the maximum line length is 4096 chars (including | |
1657 | * the line termination char); lines longer than 4096 chars are | |
1658 | * truncated. After 4095 chars, input data is still processed but | |
1659 | * not stored. Overflow processing ensures the tty can always | |
1660 | * receive more input until at least one line can be read. | |
1661 | * | |
1662 | * In non-canonical mode, the read buffer will only accept 4095 chars; | |
1663 | * this provides the necessary space for a newline char if the input | |
1664 | * mode is switched to canonical. | |
1665 | * | |
1666 | * Note it is possible for the read buffer to _contain_ 4096 chars | |
1667 | * in non-canonical mode: the read buffer could already contain the | |
1668 | * maximum canon line of 4096 chars when the mode is switched to | |
1669 | * non-canonical. | |
1670 | * | |
1671 | * n_tty_receive_buf()/producer path: | |
1672 | * claims non-exclusive termios_rwsem | |
1673 | * publishes commit_head or canon_head | |
1674 | */ | |
5c32d123 PH |
1675 | static int |
1676 | n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, | |
1677 | char *fp, int count, int flow) | |
24a89d1c PH |
1678 | { |
1679 | struct n_tty_data *ldata = tty->disc_data; | |
fb5ef9e7 | 1680 | int room, n, rcvd = 0, overflow; |
24a89d1c | 1681 | |
9356b535 PH |
1682 | down_read(&tty->termios_rwsem); |
1683 | ||
19e2ad6a | 1684 | while (1) { |
70aca71f | 1685 | /* |
06c49f9f PH |
1686 | * When PARMRK is set, each input char may take up to 3 chars |
1687 | * in the read buf; reduce the buffer space avail by 3x | |
70aca71f PH |
1688 | * |
1689 | * If we are doing input canonicalization, and there are no | |
1690 | * pending newlines, let characters through without limit, so | |
1691 | * that erase characters will be handled. Other excess | |
1692 | * characters will be beeped. | |
1693 | * | |
1694 | * paired with store in *_copy_from_read_buf() -- guarantees | |
1695 | * the consumer has loaded the data in read_buf up to the new | |
1696 | * read_tail (so this producer will not overwrite unread data) | |
1697 | */ | |
1698 | size_t tail = smp_load_acquire(&ldata->read_tail); | |
70aca71f | 1699 | |
fb5ef9e7 | 1700 | room = N_TTY_BUF_SIZE - (ldata->read_head - tail); |
70aca71f | 1701 | if (I_PARMRK(tty)) |
fb5ef9e7 PH |
1702 | room = (room + 2) / 3; |
1703 | room--; | |
1704 | if (room <= 0) { | |
1705 | overflow = ldata->icanon && ldata->canon_head == tail; | |
1706 | if (overflow && room < 0) | |
1707 | ldata->read_head--; | |
1708 | room = overflow; | |
1709 | ldata->no_room = flow && !room; | |
1710 | } else | |
1711 | overflow = 0; | |
70aca71f | 1712 | |
19e2ad6a | 1713 | n = min(count, room); |
fb5ef9e7 | 1714 | if (!n) |
19e2ad6a | 1715 | break; |
fb5ef9e7 PH |
1716 | |
1717 | /* ignore parity errors if handling overflow */ | |
1718 | if (!overflow || !fp || *fp != TTY_PARITY) | |
1719 | __receive_buf(tty, cp, fp, n); | |
1720 | ||
19e2ad6a PH |
1721 | cp += n; |
1722 | if (fp) | |
1723 | fp += n; | |
1724 | count -= n; | |
1725 | rcvd += n; | |
4a23a4df | 1726 | } |
24a89d1c | 1727 | |
19e2ad6a | 1728 | tty->receive_room = room; |
fb5ef9e7 PH |
1729 | |
1730 | /* Unthrottle if handling overflow on pty */ | |
1731 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { | |
1732 | if (overflow) { | |
1733 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1734 | tty_unthrottle_safe(tty); | |
1735 | __tty_set_flow_change(tty, 0); | |
1736 | } | |
1737 | } else | |
1738 | n_tty_check_throttle(tty); | |
1739 | ||
9356b535 PH |
1740 | up_read(&tty->termios_rwsem); |
1741 | ||
19e2ad6a | 1742 | return rcvd; |
24a89d1c PH |
1743 | } |
1744 | ||
5c32d123 PH |
1745 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1746 | char *fp, int count) | |
1747 | { | |
1748 | n_tty_receive_buf_common(tty, cp, fp, count, 0); | |
1749 | } | |
1750 | ||
1751 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1752 | char *fp, int count) | |
1753 | { | |
1754 | return n_tty_receive_buf_common(tty, cp, fp, count, 1); | |
1755 | } | |
1756 | ||
1da177e4 LT |
1757 | /** |
1758 | * n_tty_set_termios - termios data changed | |
1759 | * @tty: terminal | |
1760 | * @old: previous data | |
1761 | * | |
1762 | * Called by the tty layer when the user changes termios flags so | |
1763 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1764 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1765 | * guaranteed that this function will not be re-entered or in progress |
1766 | * when the ldisc is closed. | |
17b82060 | 1767 | * |
6a1c0680 | 1768 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1769 | */ |
4edf1827 AC |
1770 | |
1771 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1772 | { |
53c5ee2c | 1773 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1774 | |
c786f74e | 1775 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { |
3fe780b3 | 1776 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1777 | ldata->line_start = ldata->read_tail; |
1778 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1779 | ldata->canon_head = ldata->read_tail; | |
1780 | ldata->push = 0; | |
1781 | } else { | |
1782 | set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), | |
1783 | ldata->read_flags); | |
1784 | ldata->canon_head = ldata->read_head; | |
1785 | ldata->push = 1; | |
1786 | } | |
70aca71f | 1787 | ldata->commit_head = ldata->read_head; |
53c5ee2c | 1788 | ldata->erasing = 0; |
6f9b028a | 1789 | ldata->lnext = 0; |
47afa7a5 AC |
1790 | } |
1791 | ||
53c5ee2c | 1792 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1793 | |
1da177e4 LT |
1794 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1795 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1796 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1797 | I_PARMRK(tty)) { | |
1bb9d562 | 1798 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1799 | |
1800 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1801 | set_bit('\r', ldata->char_map); |
1da177e4 | 1802 | if (I_INLCR(tty)) |
1bb9d562 | 1803 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1804 | |
1805 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1806 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1807 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1808 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1809 | set_bit('\n', ldata->char_map); | |
1810 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1811 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1812 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1813 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1814 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1815 | if (L_ECHO(tty)) |
1816 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1817 | ldata->char_map); |
1da177e4 LT |
1818 | } |
1819 | } | |
1820 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1821 | set_bit(START_CHAR(tty), ldata->char_map); |
1822 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1823 | } |
1824 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1825 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1826 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1827 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1828 | } |
1bb9d562 | 1829 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1830 | ldata->raw = 0; |
1831 | ldata->real_raw = 0; | |
1da177e4 | 1832 | } else { |
53c5ee2c | 1833 | ldata->raw = 1; |
1da177e4 LT |
1834 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1835 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1836 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1837 | ldata->real_raw = 1; |
1da177e4 | 1838 | else |
53c5ee2c | 1839 | ldata->real_raw = 0; |
1da177e4 | 1840 | } |
dab73b4e WY |
1841 | /* |
1842 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1843 | * been stopped by STOP_CHAR(tty) before it. | |
1844 | */ | |
e2613be5 | 1845 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { |
dab73b4e | 1846 | start_tty(tty); |
e2613be5 PH |
1847 | process_echoes(tty); |
1848 | } | |
dab73b4e | 1849 | |
f34d7a5b | 1850 | /* The termios change make the tty ready for I/O */ |
e81107d4 KT |
1851 | wake_up_interruptible(&tty->write_wait); |
1852 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1853 | } |
1854 | ||
1855 | /** | |
1856 | * n_tty_close - close the ldisc for this tty | |
1857 | * @tty: device | |
1858 | * | |
4edf1827 AC |
1859 | * Called from the terminal layer when this line discipline is |
1860 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1861 | * discipline change. The function will not be called while other |
1862 | * ldisc methods are in progress. | |
1863 | */ | |
4edf1827 | 1864 | |
1da177e4 LT |
1865 | static void n_tty_close(struct tty_struct *tty) |
1866 | { | |
70ece7a7 JS |
1867 | struct n_tty_data *ldata = tty->disc_data; |
1868 | ||
79901317 PH |
1869 | if (tty->link) |
1870 | n_tty_packet_mode_flush(tty); | |
1871 | ||
20bafb3d | 1872 | vfree(ldata); |
70ece7a7 | 1873 | tty->disc_data = NULL; |
1da177e4 LT |
1874 | } |
1875 | ||
1876 | /** | |
1877 | * n_tty_open - open an ldisc | |
1878 | * @tty: terminal to open | |
1879 | * | |
4edf1827 | 1880 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1881 | * terminal device. Can sleep. Called serialized so that no |
1882 | * other events will occur in parallel. No further open will occur | |
1883 | * until a close. | |
1884 | */ | |
1885 | ||
1886 | static int n_tty_open(struct tty_struct *tty) | |
1887 | { | |
70ece7a7 JS |
1888 | struct n_tty_data *ldata; |
1889 | ||
20bafb3d PH |
1890 | /* Currently a malloc failure here can panic */ |
1891 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1892 | if (!ldata) |
1893 | goto err; | |
1894 | ||
53c5ee2c | 1895 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1896 | mutex_init(&ldata->atomic_read_lock); |
1897 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1898 | |
70ece7a7 | 1899 | tty->disc_data = ldata; |
b66f4fa5 | 1900 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1901 | ldata->column = 0; |
20bafb3d | 1902 | ldata->canon_column = 0; |
f6c8dbe6 | 1903 | ldata->minimum_to_wake = 1; |
20bafb3d PH |
1904 | ldata->num_overrun = 0; |
1905 | ldata->no_room = 0; | |
1906 | ldata->lnext = 0; | |
1da177e4 | 1907 | tty->closing = 0; |
b66f4fa5 PH |
1908 | /* indicate buffer work may resume */ |
1909 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1910 | n_tty_set_termios(tty, NULL); | |
1911 | tty_unthrottle(tty); | |
70ece7a7 | 1912 | |
1da177e4 | 1913 | return 0; |
70ece7a7 | 1914 | err: |
b91939f5 | 1915 | return -ENOMEM; |
1da177e4 LT |
1916 | } |
1917 | ||
eafbe67f | 1918 | static inline int input_available_p(struct tty_struct *tty, int poll) |
1da177e4 | 1919 | { |
53c5ee2c | 1920 | struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1921 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1922 | |
25e8d0ed PH |
1923 | if (ldata->icanon && !L_EXTPROC(tty)) |
1924 | return ldata->canon_head != ldata->read_tail; | |
1925 | else | |
70aca71f | 1926 | return ldata->commit_head - ldata->read_tail >= amt; |
1da177e4 LT |
1927 | } |
1928 | ||
1a48632f PH |
1929 | static inline int check_other_done(struct tty_struct *tty) |
1930 | { | |
1931 | int done = test_bit(TTY_OTHER_DONE, &tty->flags); | |
1932 | if (done) { | |
1933 | /* paired with cmpxchg() in check_other_closed(); ensures | |
1934 | * read buffer head index is not stale | |
1935 | */ | |
1936 | smp_mb__after_atomic(); | |
1937 | } | |
1938 | return done; | |
1939 | } | |
1940 | ||
1da177e4 | 1941 | /** |
bbd20759 | 1942 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1943 | * @tty: terminal device |
1944 | * @b: user data | |
1945 | * @nr: size of data | |
1946 | * | |
11a96d18 | 1947 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1948 | * ICANON is off; it copies characters straight from the tty queue to |
1949 | * user space directly. It can be profitably called twice; once to | |
1950 | * drain the space from the tail pointer to the (physical) end of the | |
1951 | * buffer, and once to drain the space from the (physical) beginning of | |
1952 | * the buffer to head pointer. | |
1953 | * | |
bddc7152 | 1954 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1955 | * |
6d76bd26 PH |
1956 | * n_tty_read()/consumer path: |
1957 | * caller holds non-exclusive termios_rwsem | |
1958 | * read_tail published | |
1da177e4 | 1959 | */ |
4edf1827 | 1960 | |
33f0f88f | 1961 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1962 | unsigned char __user **b, |
1963 | size_t *nr) | |
1964 | ||
1965 | { | |
53c5ee2c | 1966 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1967 | int retval; |
1968 | size_t n; | |
3fa10cc8 | 1969 | bool is_eof; |
70aca71f | 1970 | size_t head = smp_load_acquire(&ldata->commit_head); |
bc5a5e3f | 1971 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1972 | |
1973 | retval = 0; | |
70aca71f | 1974 | n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail); |
1da177e4 | 1975 | n = min(*nr, n); |
1da177e4 | 1976 | if (n) { |
e661cf70 PH |
1977 | const unsigned char *from = read_buf_addr(ldata, tail); |
1978 | retval = copy_to_user(*b, from, n); | |
1da177e4 | 1979 | n -= retval; |
e661cf70 PH |
1980 | is_eof = n == 1 && *from == EOF_CHAR(tty); |
1981 | tty_audit_add_data(tty, from, n, ldata->icanon); | |
70aca71f | 1982 | smp_store_release(&ldata->read_tail, ldata->read_tail + n); |
26df6d13 | 1983 | /* Turn single EOF into zero-length read */ |
70aca71f PH |
1984 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && |
1985 | (head == ldata->read_tail)) | |
3fa10cc8 | 1986 | n = 0; |
1da177e4 LT |
1987 | *b += n; |
1988 | *nr -= n; | |
1989 | } | |
1990 | return retval; | |
1991 | } | |
1992 | ||
88bb0de3 | 1993 | /** |
32f13521 | 1994 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1995 | * @tty: terminal device |
1996 | * @b: user data | |
1997 | * @nr: size of data | |
1998 | * | |
1999 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
2000 | * it copies one line of input up to and including the line-delimiting |
2001 | * character into the user-space buffer. | |
88bb0de3 | 2002 | * |
4d0ed182 PH |
2003 | * NB: When termios is changed from non-canonical to canonical mode and |
2004 | * the read buffer contains data, n_tty_set_termios() simulates an EOF | |
2005 | * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. | |
2006 | * This causes data already processed as input to be immediately available | |
2007 | * as input although a newline has not been received. | |
2008 | * | |
88bb0de3 | 2009 | * Called under the atomic_read_lock mutex |
6d76bd26 PH |
2010 | * |
2011 | * n_tty_read()/consumer path: | |
2012 | * caller holds non-exclusive termios_rwsem | |
2013 | * read_tail published | |
88bb0de3 PH |
2014 | */ |
2015 | ||
32f13521 PH |
2016 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
2017 | unsigned char __user **b, | |
2018 | size_t *nr) | |
88bb0de3 PH |
2019 | { |
2020 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 2021 | size_t n, size, more, c; |
bc5a5e3f PH |
2022 | size_t eol; |
2023 | size_t tail; | |
2024 | int ret, found = 0; | |
88bb0de3 PH |
2025 | |
2026 | /* N.B. avoid overrun if nr == 0 */ | |
ac8f3bf8 | 2027 | if (!*nr) |
32f13521 | 2028 | return 0; |
88bb0de3 | 2029 | |
ac8f3bf8 PH |
2030 | n = min(*nr + 1, smp_load_acquire(&ldata->canon_head) - ldata->read_tail); |
2031 | ||
bc5a5e3f | 2032 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
2033 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
2034 | ||
bc5a5e3f | 2035 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2036 | __func__, *nr, tail, n, size); |
2037 | ||
2038 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2039 | more = n - (size - tail); | |
2040 | if (eol == N_TTY_BUF_SIZE && more) { | |
2041 | /* scan wrapped without finding set bit */ | |
2042 | eol = find_next_bit(ldata->read_flags, more, 0); | |
b985e9e3 PH |
2043 | found = eol != more; |
2044 | } else | |
2045 | found = eol != size; | |
32f13521 | 2046 | |
c77569d2 | 2047 | n = eol - tail; |
da555db6 MT |
2048 | if (n > N_TTY_BUF_SIZE) |
2049 | n += N_TTY_BUF_SIZE; | |
ac8f3bf8 | 2050 | c = n + found; |
32f13521 | 2051 | |
ac8f3bf8 PH |
2052 | if (!found || read_buf(ldata, eol) != __DISABLED_CHAR) { |
2053 | c = min(*nr, c); | |
2054 | n = c; | |
40d5e090 | 2055 | } |
32f13521 | 2056 | |
679e7c29 PH |
2057 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu tail:%zu more:%zu\n", |
2058 | __func__, eol, found, n, c, tail, more); | |
32f13521 | 2059 | |
679e7c29 | 2060 | ret = tty_copy_to_user(tty, *b, tail, n); |
32f13521 PH |
2061 | if (ret) |
2062 | return -EFAULT; | |
2063 | *b += n; | |
2064 | *nr -= n; | |
2065 | ||
a73d3d69 | 2066 | if (found) |
6d76bd26 | 2067 | clear_bit(eol, ldata->read_flags); |
70aca71f | 2068 | smp_store_release(&ldata->read_tail, ldata->read_tail + c); |
88bb0de3 | 2069 | |
40d5e090 | 2070 | if (found) { |
4d0ed182 PH |
2071 | if (!ldata->push) |
2072 | ldata->line_start = ldata->read_tail; | |
2073 | else | |
2074 | ldata->push = 0; | |
32f13521 | 2075 | tty_audit_push(tty); |
40d5e090 | 2076 | } |
ac8f3bf8 | 2077 | return 0; |
88bb0de3 PH |
2078 | } |
2079 | ||
cc4191dc | 2080 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2081 | size_t, loff_t *); |
1da177e4 LT |
2082 | |
2083 | /** | |
2084 | * job_control - check job control | |
2085 | * @tty: tty | |
2086 | * @file: file handle | |
2087 | * | |
2088 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2089 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2090 | * error code if action should be taken. |
04f378b1 | 2091 | * |
01a5e440 PH |
2092 | * Locking: redirected write test is safe |
2093 | * current->signal->tty check is safe | |
2094 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2095 | */ |
4edf1827 | 2096 | |
1da177e4 LT |
2097 | static int job_control(struct tty_struct *tty, struct file *file) |
2098 | { | |
2099 | /* Job control check -- must be done at start and after | |
2100 | every sleep (POSIX.1 7.1.1.4). */ | |
2101 | /* NOTE: not yet done after every sleep pending a thorough | |
2102 | check of the logic of this change. -- jlc */ | |
2103 | /* don't stop on /dev/console */ | |
2812d9e9 | 2104 | if (file->f_op->write == redirected_tty_write) |
01a5e440 PH |
2105 | return 0; |
2106 | ||
2812d9e9 | 2107 | return __tty_check_change(tty, SIGTTIN); |
1da177e4 | 2108 | } |
4edf1827 | 2109 | |
1da177e4 LT |
2110 | |
2111 | /** | |
11a96d18 | 2112 | * n_tty_read - read function for tty |
1da177e4 LT |
2113 | * @tty: tty device |
2114 | * @file: file object | |
2115 | * @buf: userspace buffer pointer | |
2116 | * @nr: size of I/O | |
2117 | * | |
2118 | * Perform reads for the line discipline. We are guaranteed that the | |
2119 | * line discipline will not be closed under us but we may get multiple | |
2120 | * parallel readers and must handle this ourselves. We may also get | |
2121 | * a hangup. Always called in user context, may sleep. | |
2122 | * | |
2123 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2124 | * |
2125 | * n_tty_read()/consumer path: | |
2126 | * claims non-exclusive termios_rwsem | |
2127 | * publishes read_tail | |
1da177e4 | 2128 | */ |
4edf1827 | 2129 | |
11a96d18 | 2130 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2131 | unsigned char __user *buf, size_t nr) |
2132 | { | |
53c5ee2c | 2133 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 2134 | unsigned char __user *b = buf; |
97d9e28d | 2135 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1a48632f | 2136 | int c, done; |
1da177e4 LT |
2137 | int minimum, time; |
2138 | ssize_t retval = 0; | |
1da177e4 | 2139 | long timeout; |
04f378b1 | 2140 | int packet; |
2c5dc464 | 2141 | size_t tail; |
1da177e4 | 2142 | |
1da177e4 | 2143 | c = job_control(tty, file); |
4edf1827 | 2144 | if (c < 0) |
1da177e4 | 2145 | return c; |
4edf1827 | 2146 | |
aefceaf4 PH |
2147 | /* |
2148 | * Internal serialization of reads. | |
2149 | */ | |
2150 | if (file->f_flags & O_NONBLOCK) { | |
2151 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2152 | return -EAGAIN; | |
2153 | } else { | |
2154 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2155 | return -ERESTARTSYS; | |
2156 | } | |
2157 | ||
9356b535 PH |
2158 | down_read(&tty->termios_rwsem); |
2159 | ||
1da177e4 LT |
2160 | minimum = time = 0; |
2161 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2162 | if (!ldata->icanon) { |
1da177e4 LT |
2163 | minimum = MIN_CHAR(tty); |
2164 | if (minimum) { | |
a6e54319 | 2165 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2166 | if (time) |
f6c8dbe6 | 2167 | ldata->minimum_to_wake = 1; |
1da177e4 | 2168 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
2169 | (ldata->minimum_to_wake > minimum)) |
2170 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 2171 | } else { |
a6e54319 | 2172 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2173 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2174 | } |
2175 | } | |
2176 | ||
04f378b1 | 2177 | packet = tty->packet; |
2c5dc464 | 2178 | tail = ldata->read_tail; |
1da177e4 LT |
2179 | |
2180 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2181 | while (nr) { |
2182 | /* First test for status change. */ | |
04f378b1 | 2183 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2184 | unsigned char cs; |
2185 | if (b != buf) | |
2186 | break; | |
6054c16e | 2187 | spin_lock_irq(&tty->link->ctrl_lock); |
1da177e4 LT |
2188 | cs = tty->link->ctrl_status; |
2189 | tty->link->ctrl_status = 0; | |
6054c16e | 2190 | spin_unlock_irq(&tty->link->ctrl_lock); |
eab25a5c | 2191 | if (put_user(cs, b)) { |
1da177e4 | 2192 | retval = -EFAULT; |
1da177e4 LT |
2193 | break; |
2194 | } | |
eab25a5c | 2195 | b++; |
1da177e4 LT |
2196 | nr--; |
2197 | break; | |
2198 | } | |
4edf1827 | 2199 | |
f6c8dbe6 | 2200 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2201 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2202 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2203 | |
1a48632f PH |
2204 | done = check_other_done(tty); |
2205 | ||
1da177e4 | 2206 | if (!input_available_p(tty, 0)) { |
1a48632f | 2207 | if (done) { |
52bce7f8 PH |
2208 | retval = -EIO; |
2209 | break; | |
f8747d4a | 2210 | } |
52bce7f8 PH |
2211 | if (tty_hung_up_p(file)) |
2212 | break; | |
2213 | if (!timeout) | |
2214 | break; | |
2215 | if (file->f_flags & O_NONBLOCK) { | |
2216 | retval = -EAGAIN; | |
1da177e4 LT |
2217 | break; |
2218 | } | |
52bce7f8 PH |
2219 | if (signal_pending(current)) { |
2220 | retval = -ERESTARTSYS; | |
2221 | break; | |
2222 | } | |
52bce7f8 | 2223 | up_read(&tty->termios_rwsem); |
9356b535 | 2224 | |
37da7bbb LT |
2225 | timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, |
2226 | timeout); | |
9356b535 | 2227 | |
52bce7f8 PH |
2228 | down_read(&tty->termios_rwsem); |
2229 | continue; | |
1da177e4 LT |
2230 | } |
2231 | ||
53c5ee2c | 2232 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2233 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
ac8f3bf8 | 2234 | if (retval) |
1da177e4 LT |
2235 | break; |
2236 | } else { | |
2237 | int uncopied; | |
95ea90db PH |
2238 | |
2239 | /* Deal with packet mode. */ | |
2240 | if (packet && b == buf) { | |
eab25a5c | 2241 | if (put_user(TIOCPKT_DATA, b)) { |
95ea90db | 2242 | retval = -EFAULT; |
95ea90db PH |
2243 | break; |
2244 | } | |
eab25a5c | 2245 | b++; |
95ea90db PH |
2246 | nr--; |
2247 | } | |
2248 | ||
1da177e4 LT |
2249 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2250 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2251 | if (uncopied) { | |
2252 | retval = -EFAULT; | |
2253 | break; | |
2254 | } | |
2255 | } | |
2256 | ||
6367ca72 | 2257 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2258 | |
2259 | if (b - buf >= minimum) | |
2260 | break; | |
2261 | if (time) | |
2262 | timeout = time; | |
2263 | } | |
2c5dc464 PH |
2264 | if (tail != ldata->read_tail) |
2265 | n_tty_kick_worker(tty); | |
42458f41 PH |
2266 | up_read(&tty->termios_rwsem); |
2267 | ||
1da177e4 | 2268 | remove_wait_queue(&tty->read_wait, &wait); |
1da177e4 | 2269 | if (!waitqueue_active(&tty->read_wait)) |
f6c8dbe6 | 2270 | ldata->minimum_to_wake = minimum; |
1da177e4 | 2271 | |
aebf0453 PH |
2272 | mutex_unlock(&ldata->atomic_read_lock); |
2273 | ||
40d5e090 PH |
2274 | if (b - buf) |
2275 | retval = b - buf; | |
1da177e4 LT |
2276 | |
2277 | return retval; | |
2278 | } | |
2279 | ||
2280 | /** | |
11a96d18 | 2281 | * n_tty_write - write function for tty |
1da177e4 LT |
2282 | * @tty: tty device |
2283 | * @file: file object | |
2284 | * @buf: userspace buffer pointer | |
2285 | * @nr: size of I/O | |
2286 | * | |
a88a69c9 | 2287 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2288 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2289 | * and other such events. Since the receive code will echo characters, |
2290 | * thus calling driver write methods, the output_lock is used in | |
2291 | * the output processing functions called here as well as in the | |
2292 | * echo processing function to protect the column state and space | |
2293 | * left in the buffer. | |
1da177e4 LT |
2294 | * |
2295 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2296 | * |
2297 | * Locking: output_lock to protect column state and space left | |
2298 | * (note that the process_output*() functions take this | |
2299 | * lock themselves) | |
1da177e4 | 2300 | */ |
4edf1827 | 2301 | |
11a96d18 | 2302 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2303 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2304 | { |
2305 | const unsigned char *b = buf; | |
97d9e28d | 2306 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2307 | int c; |
2308 | ssize_t retval = 0; | |
2309 | ||
2310 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2311 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2312 | retval = tty_check_change(tty); | |
2313 | if (retval) | |
2314 | return retval; | |
2315 | } | |
2316 | ||
9356b535 PH |
2317 | down_read(&tty->termios_rwsem); |
2318 | ||
a88a69c9 JP |
2319 | /* Write out any echoed characters that are still pending */ |
2320 | process_echoes(tty); | |
300a6204 | 2321 | |
1da177e4 LT |
2322 | add_wait_queue(&tty->write_wait, &wait); |
2323 | while (1) { | |
1da177e4 LT |
2324 | if (signal_pending(current)) { |
2325 | retval = -ERESTARTSYS; | |
2326 | break; | |
2327 | } | |
2328 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2329 | retval = -EIO; | |
2330 | break; | |
2331 | } | |
582f5590 | 2332 | if (O_OPOST(tty)) { |
1da177e4 | 2333 | while (nr > 0) { |
a88a69c9 | 2334 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2335 | if (num < 0) { |
2336 | if (num == -EAGAIN) | |
2337 | break; | |
2338 | retval = num; | |
2339 | goto break_out; | |
2340 | } | |
2341 | b += num; | |
2342 | nr -= num; | |
2343 | if (nr == 0) | |
2344 | break; | |
2345 | c = *b; | |
a88a69c9 | 2346 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2347 | break; |
2348 | b++; nr--; | |
2349 | } | |
f34d7a5b AC |
2350 | if (tty->ops->flush_chars) |
2351 | tty->ops->flush_chars(tty); | |
1da177e4 | 2352 | } else { |
4291086b PH |
2353 | struct n_tty_data *ldata = tty->disc_data; |
2354 | ||
d6afe27b | 2355 | while (nr > 0) { |
4291086b | 2356 | mutex_lock(&ldata->output_lock); |
f34d7a5b | 2357 | c = tty->ops->write(tty, b, nr); |
4291086b | 2358 | mutex_unlock(&ldata->output_lock); |
d6afe27b RZ |
2359 | if (c < 0) { |
2360 | retval = c; | |
2361 | goto break_out; | |
2362 | } | |
2363 | if (!c) | |
2364 | break; | |
2365 | b += c; | |
2366 | nr -= c; | |
1da177e4 | 2367 | } |
1da177e4 LT |
2368 | } |
2369 | if (!nr) | |
2370 | break; | |
2371 | if (file->f_flags & O_NONBLOCK) { | |
2372 | retval = -EAGAIN; | |
2373 | break; | |
2374 | } | |
9356b535 PH |
2375 | up_read(&tty->termios_rwsem); |
2376 | ||
97d9e28d | 2377 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
9356b535 PH |
2378 | |
2379 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2380 | } |
2381 | break_out: | |
1da177e4 | 2382 | remove_wait_queue(&tty->write_wait, &wait); |
ff8cb0fd TP |
2383 | if (b - buf != nr && tty->fasync) |
2384 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2385 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2386 | return (b - buf) ? b - buf : retval; |
2387 | } | |
2388 | ||
2389 | /** | |
11a96d18 | 2390 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2391 | * @tty: terminal device |
2392 | * @file: file accessing it | |
2393 | * @wait: poll table | |
2394 | * | |
2395 | * Called when the line discipline is asked to poll() for data or | |
2396 | * for special events. This code is not serialized with respect to | |
2397 | * other events save open/close. | |
2398 | * | |
2399 | * This code must be sure never to sleep through a hangup. | |
2400 | * Called without the kernel lock held - fine | |
1da177e4 | 2401 | */ |
4edf1827 | 2402 | |
11a96d18 | 2403 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2404 | poll_table *wait) |
1da177e4 | 2405 | { |
f6c8dbe6 | 2406 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2407 | unsigned int mask = 0; |
2408 | ||
2409 | poll_wait(file, &tty->read_wait, wait); | |
2410 | poll_wait(file, &tty->write_wait, wait); | |
1a48632f PH |
2411 | if (check_other_done(tty)) |
2412 | mask |= POLLHUP; | |
eafbe67f | 2413 | if (input_available_p(tty, 1)) |
1da177e4 LT |
2414 | mask |= POLLIN | POLLRDNORM; |
2415 | if (tty->packet && tty->link->ctrl_status) | |
2416 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
1da177e4 LT |
2417 | if (tty_hung_up_p(file)) |
2418 | mask |= POLLHUP; | |
2419 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2420 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2421 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2422 | else |
f6c8dbe6 | 2423 | ldata->minimum_to_wake = 1; |
1da177e4 | 2424 | } |
f34d7a5b AC |
2425 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2426 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2427 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2428 | mask |= POLLOUT | POLLWRNORM; |
2429 | return mask; | |
2430 | } | |
2431 | ||
57c94121 | 2432 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2433 | { |
bc5a5e3f | 2434 | size_t nr, head, tail; |
47afa7a5 | 2435 | |
a73d3d69 | 2436 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2437 | return 0; |
ba2e68ac JS |
2438 | head = ldata->canon_head; |
2439 | tail = ldata->read_tail; | |
bc5a5e3f | 2440 | nr = head - tail; |
47afa7a5 AC |
2441 | /* Skip EOF-chars.. */ |
2442 | while (head != tail) { | |
bc5a5e3f PH |
2443 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2444 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2445 | nr--; |
bc5a5e3f | 2446 | tail++; |
47afa7a5 AC |
2447 | } |
2448 | return nr; | |
2449 | } | |
2450 | ||
2451 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2452 | unsigned int cmd, unsigned long arg) | |
2453 | { | |
ba2e68ac | 2454 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2455 | int retval; |
2456 | ||
2457 | switch (cmd) { | |
2458 | case TIOCOUTQ: | |
2459 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2460 | case TIOCINQ: | |
6d76bd26 | 2461 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2462 | if (L_ICANON(tty)) |
57c94121 | 2463 | retval = inq_canon(ldata); |
6d76bd26 PH |
2464 | else |
2465 | retval = read_cnt(ldata); | |
2466 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2467 | return put_user(retval, (unsigned int __user *) arg); |
2468 | default: | |
2469 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2470 | } | |
2471 | } | |
2472 | ||
f6c8dbe6 PH |
2473 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2474 | { | |
2475 | struct n_tty_data *ldata = tty->disc_data; | |
2476 | ||
2477 | if (!waitqueue_active(&tty->read_wait)) { | |
2478 | if (on) | |
2479 | ldata->minimum_to_wake = 1; | |
2480 | else if (!tty->fasync) | |
2481 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2482 | } | |
2483 | } | |
2484 | ||
27228732 | 2485 | static struct tty_ldisc_ops n_tty_ops = { |
e10cc1df PF |
2486 | .magic = TTY_LDISC_MAGIC, |
2487 | .name = "n_tty", | |
2488 | .open = n_tty_open, | |
2489 | .close = n_tty_close, | |
2490 | .flush_buffer = n_tty_flush_buffer, | |
11a96d18 AC |
2491 | .read = n_tty_read, |
2492 | .write = n_tty_write, | |
e10cc1df PF |
2493 | .ioctl = n_tty_ioctl, |
2494 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2495 | .poll = n_tty_poll, |
e10cc1df | 2496 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2497 | .write_wakeup = n_tty_write_wakeup, |
2498 | .fasync = n_tty_fasync, | |
24a89d1c | 2499 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2500 | }; |
572b9adb RG |
2501 | |
2502 | /** | |
2503 | * n_tty_inherit_ops - inherit N_TTY methods | |
2504 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2505 | * | |
27228732 | 2506 | * Enables a 'subclass' line discipline to 'inherit' N_TTY methods. |
572b9adb RG |
2507 | */ |
2508 | ||
2509 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2510 | { | |
27228732 | 2511 | *ops = n_tty_ops; |
572b9adb RG |
2512 | ops->owner = NULL; |
2513 | ops->refcount = ops->flags = 0; | |
2514 | } | |
2515 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); | |
27228732 PH |
2516 | |
2517 | void __init n_tty_init(void) | |
2518 | { | |
2519 | tty_register_ldisc(N_TTY, &n_tty_ops); | |
2520 | } |