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 | ||
522ed776 MT |
156 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
157 | unsigned char __user *ptr) | |
158 | { | |
53c5ee2c JS |
159 | struct n_tty_data *ldata = tty->disc_data; |
160 | ||
161 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
162 | return put_user(x, ptr); |
163 | } | |
164 | ||
679e7c29 PH |
165 | static int tty_copy_to_user(struct tty_struct *tty, void __user *to, |
166 | size_t tail, size_t n) | |
72586c60 LA |
167 | { |
168 | struct n_tty_data *ldata = tty->disc_data; | |
679e7c29 PH |
169 | size_t size = N_TTY_BUF_SIZE - tail; |
170 | const void *from = read_buf_addr(ldata, tail); | |
171 | int uncopied; | |
172 | ||
173 | if (n > size) { | |
174 | tty_audit_add_data(tty, from, size, ldata->icanon); | |
175 | uncopied = copy_to_user(to, from, size); | |
176 | if (uncopied) | |
177 | return uncopied; | |
178 | to += size; | |
179 | n -= size; | |
180 | from = ldata->read_buf; | |
181 | } | |
72586c60 | 182 | |
6b2a3d62 | 183 | tty_audit_add_data(tty, from, n, ldata->icanon); |
72586c60 LA |
184 | return copy_to_user(to, from, n); |
185 | } | |
186 | ||
24a89d1c | 187 | /** |
2c5dc464 | 188 | * n_tty_kick_worker - start input worker (if required) |
24a89d1c PH |
189 | * @tty: terminal |
190 | * | |
2c5dc464 | 191 | * Re-schedules the flip buffer work if it may have stopped |
24a89d1c | 192 | * |
6d76bd26 PH |
193 | * Caller holds exclusive termios_rwsem |
194 | * or | |
195 | * n_tty_read()/consumer path: | |
196 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
197 | */ |
198 | ||
2c5dc464 | 199 | static void n_tty_kick_worker(struct tty_struct *tty) |
7879a9f9 | 200 | { |
24a89d1c PH |
201 | struct n_tty_data *ldata = tty->disc_data; |
202 | ||
2c5dc464 PH |
203 | /* Did the input worker stop? Restart it */ |
204 | if (unlikely(ldata->no_room)) { | |
24a89d1c PH |
205 | ldata->no_room = 0; |
206 | ||
ecbbfd44 | 207 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 208 | "scheduling with invalid itty\n"); |
21622939 PH |
209 | /* see if ldisc has been killed - if so, this means that |
210 | * even though the ldisc has been halted and ->buf.work | |
211 | * cancelled, ->buf.work is about to be rescheduled | |
212 | */ | |
213 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
214 | "scheduling buffer work for halted ldisc\n"); | |
e176058f | 215 | tty_buffer_restart_work(tty->port); |
ecbbfd44 | 216 | } |
55db4c64 LT |
217 | } |
218 | ||
9a4aec2d PH |
219 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
220 | { | |
221 | struct n_tty_data *ldata = tty->disc_data; | |
222 | ssize_t n = 0; | |
223 | ||
224 | if (!ldata->icanon) | |
70aca71f | 225 | n = ldata->commit_head - ldata->read_tail; |
9a4aec2d PH |
226 | else |
227 | n = ldata->canon_head - ldata->read_tail; | |
228 | return n; | |
229 | } | |
230 | ||
ee0bab83 PH |
231 | /** |
232 | * n_tty_write_wakeup - asynchronous I/O notifier | |
233 | * @tty: tty device | |
234 | * | |
235 | * Required for the ptys, serial driver etc. since processes | |
236 | * that attach themselves to the master and rely on ASYNC | |
237 | * IO must be woken up | |
238 | */ | |
239 | ||
240 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
241 | { | |
242 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) | |
243 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
244 | } | |
245 | ||
4a23a4df | 246 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 247 | { |
a342846f PH |
248 | struct n_tty_data *ldata = tty->disc_data; |
249 | ||
6367ca72 PH |
250 | /* |
251 | * Check the remaining room for the input canonicalization | |
252 | * mode. We don't want to throttle the driver if we're in | |
253 | * canonical mode and don't have a newline yet! | |
254 | */ | |
a342846f PH |
255 | if (ldata->icanon && ldata->canon_head == ldata->read_tail) |
256 | return; | |
257 | ||
6367ca72 PH |
258 | while (1) { |
259 | int throttled; | |
260 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
5e28cca1 | 261 | if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE) |
6367ca72 PH |
262 | break; |
263 | throttled = tty_throttle_safe(tty); | |
264 | if (!throttled) | |
265 | break; | |
266 | } | |
267 | __tty_set_flow_change(tty, 0); | |
268 | } | |
269 | ||
4b293492 | 270 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 271 | { |
3afb1b39 PH |
272 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
273 | tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { | |
274 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
275 | return; | |
276 | if (!tty->count) | |
277 | return; | |
2c5dc464 | 278 | n_tty_kick_worker(tty); |
3afb1b39 | 279 | n_tty_write_wakeup(tty->link); |
6c67716d PH |
280 | if (waitqueue_active(&tty->link->write_wait)) |
281 | wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); | |
3afb1b39 PH |
282 | return; |
283 | } | |
284 | ||
6367ca72 PH |
285 | /* If there is enough space in the read buffer now, let the |
286 | * low-level driver know. We use chars_in_buffer() to | |
287 | * check the buffer, as it now knows about canonical mode. | |
288 | * Otherwise, if the driver is throttled and the line is | |
289 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
290 | * we won't get any more characters. | |
291 | */ | |
292 | ||
293 | while (1) { | |
294 | int unthrottled; | |
295 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
296 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
297 | break; | |
298 | if (!tty->count) | |
299 | break; | |
2c5dc464 | 300 | n_tty_kick_worker(tty); |
6367ca72 PH |
301 | unthrottled = tty_unthrottle_safe(tty); |
302 | if (!unthrottled) | |
303 | break; | |
304 | } | |
305 | __tty_set_flow_change(tty, 0); | |
306 | } | |
307 | ||
17b82060 AC |
308 | /** |
309 | * put_tty_queue - add character to tty | |
310 | * @c: character | |
57c94121 | 311 | * @ldata: n_tty data |
17b82060 | 312 | * |
6d76bd26 PH |
313 | * Add a character to the tty read_buf queue. |
314 | * | |
315 | * n_tty_receive_buf()/producer path: | |
316 | * caller holds non-exclusive termios_rwsem | |
17b82060 AC |
317 | */ |
318 | ||
19e2ad6a | 319 | static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 320 | { |
8bfbe2de CR |
321 | *read_buf_addr(ldata, ldata->read_head) = c; |
322 | ldata->read_head++; | |
1da177e4 LT |
323 | } |
324 | ||
1da177e4 LT |
325 | /** |
326 | * reset_buffer_flags - reset buffer state | |
327 | * @tty: terminal to reset | |
328 | * | |
25518c68 PH |
329 | * Reset the read buffer counters and clear the flags. |
330 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 331 | * |
6d76bd26 PH |
332 | * Locking: caller holds exclusive termios_rwsem |
333 | * (or locking is not required) | |
1da177e4 | 334 | */ |
a88a69c9 | 335 | |
b66f4fa5 | 336 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 337 | { |
a73d3d69 | 338 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 339 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
70aca71f | 340 | ldata->commit_head = 0; |
1075a6e2 | 341 | ldata->echo_mark = 0; |
40d5e090 | 342 | ldata->line_start = 0; |
a88a69c9 | 343 | |
a73d3d69 | 344 | ldata->erasing = 0; |
3fe780b3 | 345 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 | 346 | ldata->push = 0; |
1da177e4 LT |
347 | } |
348 | ||
a30737ab PH |
349 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
350 | { | |
351 | unsigned long flags; | |
352 | ||
a30737ab | 353 | if (tty->link->packet) { |
54e8e5fc | 354 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
a30737ab | 355 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; |
54e8e5fc | 356 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
e81107d4 | 357 | wake_up_interruptible(&tty->link->read_wait); |
a30737ab | 358 | } |
a30737ab PH |
359 | } |
360 | ||
1da177e4 LT |
361 | /** |
362 | * n_tty_flush_buffer - clean input queue | |
363 | * @tty: terminal device | |
364 | * | |
25518c68 PH |
365 | * Flush the input buffer. Called when the tty layer wants the |
366 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
367 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 368 | * |
6d76bd26 PH |
369 | * Holds termios_rwsem to exclude producer/consumer while |
370 | * buffer indices are reset. | |
371 | * | |
372 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 373 | */ |
4edf1827 AC |
374 | |
375 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 376 | { |
6d76bd26 | 377 | down_write(&tty->termios_rwsem); |
b66f4fa5 | 378 | reset_buffer_flags(tty->disc_data); |
2c5dc464 | 379 | n_tty_kick_worker(tty); |
4edf1827 | 380 | |
a30737ab PH |
381 | if (tty->link) |
382 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 383 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
384 | } |
385 | ||
6d76bd26 PH |
386 | /** |
387 | * n_tty_chars_in_buffer - report available bytes | |
388 | * @tty: tty device | |
389 | * | |
390 | * Report the number of characters buffered to be delivered to user | |
391 | * at this instant in time. | |
392 | * | |
393 | * Locking: exclusive termios_rwsem | |
394 | */ | |
395 | ||
a19d0c6a PH |
396 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
397 | { | |
6d76bd26 PH |
398 | ssize_t n; |
399 | ||
47534084 | 400 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
6d76bd26 PH |
401 | |
402 | down_write(&tty->termios_rwsem); | |
403 | n = chars_in_buffer(tty); | |
404 | up_write(&tty->termios_rwsem); | |
405 | return n; | |
a19d0c6a PH |
406 | } |
407 | ||
1da177e4 LT |
408 | /** |
409 | * is_utf8_continuation - utf8 multibyte check | |
410 | * @c: byte to check | |
411 | * | |
412 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
413 | * character. We use this to correctly compute the on screen size | |
414 | * of the character when printing | |
415 | */ | |
4edf1827 | 416 | |
1da177e4 LT |
417 | static inline int is_utf8_continuation(unsigned char c) |
418 | { | |
419 | return (c & 0xc0) == 0x80; | |
420 | } | |
421 | ||
422 | /** | |
423 | * is_continuation - multibyte check | |
424 | * @c: byte to check | |
425 | * | |
426 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
427 | * character and the terminal is in unicode mode. | |
428 | */ | |
4edf1827 | 429 | |
1da177e4 LT |
430 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
431 | { | |
432 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
433 | } | |
434 | ||
435 | /** | |
a88a69c9 | 436 | * do_output_char - output one character |
1da177e4 LT |
437 | * @c: character (or partial unicode symbol) |
438 | * @tty: terminal device | |
a88a69c9 | 439 | * @space: space available in tty driver write buffer |
1da177e4 | 440 | * |
a88a69c9 JP |
441 | * This is a helper function that handles one output character |
442 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
443 | * doing OPOST processing and putting the results in the |
444 | * tty driver's write buffer. | |
a88a69c9 JP |
445 | * |
446 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
447 | * and NLDLY. They simply aren't relevant in the world today. | |
448 | * If you ever need them, add them here. | |
1da177e4 | 449 | * |
a88a69c9 JP |
450 | * Returns the number of bytes of buffer space used or -1 if |
451 | * no space left. | |
452 | * | |
453 | * Locking: should be called under the output_lock to protect | |
454 | * the column state and space left in the buffer | |
1da177e4 | 455 | */ |
4edf1827 | 456 | |
a88a69c9 | 457 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 458 | { |
53c5ee2c | 459 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 460 | int spaces; |
1da177e4 | 461 | |
1da177e4 LT |
462 | if (!space) |
463 | return -1; | |
300a6204 | 464 | |
a88a69c9 JP |
465 | switch (c) { |
466 | case '\n': | |
467 | if (O_ONLRET(tty)) | |
53c5ee2c | 468 | ldata->column = 0; |
a88a69c9 JP |
469 | if (O_ONLCR(tty)) { |
470 | if (space < 2) | |
471 | return -1; | |
ba2e68ac | 472 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 473 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
474 | return 2; |
475 | } | |
ba2e68ac | 476 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
477 | break; |
478 | case '\r': | |
53c5ee2c | 479 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
480 | return 0; |
481 | if (O_OCRNL(tty)) { | |
482 | c = '\n'; | |
483 | if (O_ONLRET(tty)) | |
ba2e68ac | 484 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 485 | break; |
a88a69c9 | 486 | } |
ba2e68ac | 487 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
488 | break; |
489 | case '\t': | |
53c5ee2c | 490 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
491 | if (O_TABDLY(tty) == XTABS) { |
492 | if (space < spaces) | |
493 | return -1; | |
53c5ee2c | 494 | ldata->column += spaces; |
a88a69c9 JP |
495 | tty->ops->write(tty, " ", spaces); |
496 | return spaces; | |
1da177e4 | 497 | } |
53c5ee2c | 498 | ldata->column += spaces; |
a88a69c9 JP |
499 | break; |
500 | case '\b': | |
53c5ee2c JS |
501 | if (ldata->column > 0) |
502 | ldata->column--; | |
a88a69c9 JP |
503 | break; |
504 | default: | |
a59c0d6f JP |
505 | if (!iscntrl(c)) { |
506 | if (O_OLCUC(tty)) | |
507 | c = toupper(c); | |
508 | if (!is_continuation(c, tty)) | |
53c5ee2c | 509 | ldata->column++; |
a59c0d6f | 510 | } |
a88a69c9 | 511 | break; |
1da177e4 | 512 | } |
a88a69c9 | 513 | |
f34d7a5b | 514 | tty_put_char(tty, c); |
a88a69c9 JP |
515 | return 1; |
516 | } | |
517 | ||
518 | /** | |
519 | * process_output - output post processor | |
520 | * @c: character (or partial unicode symbol) | |
521 | * @tty: terminal device | |
522 | * | |
ee5aa7b8 JP |
523 | * Output one character with OPOST processing. |
524 | * Returns -1 when the output device is full and the character | |
525 | * must be retried. | |
a88a69c9 JP |
526 | * |
527 | * Locking: output_lock to protect column state and space left | |
528 | * (also, this is called from n_tty_write under the | |
529 | * tty layer write lock) | |
530 | */ | |
531 | ||
532 | static int process_output(unsigned char c, struct tty_struct *tty) | |
533 | { | |
bddc7152 | 534 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
535 | int space, retval; |
536 | ||
bddc7152 | 537 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
538 | |
539 | space = tty_write_room(tty); | |
540 | retval = do_output_char(c, tty, space); | |
541 | ||
bddc7152 | 542 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
543 | if (retval < 0) |
544 | return -1; | |
545 | else | |
546 | return 0; | |
1da177e4 LT |
547 | } |
548 | ||
549 | /** | |
a88a69c9 | 550 | * process_output_block - block post processor |
1da177e4 | 551 | * @tty: terminal device |
ee5aa7b8 JP |
552 | * @buf: character buffer |
553 | * @nr: number of bytes to output | |
554 | * | |
555 | * Output a block of characters with OPOST processing. | |
556 | * Returns the number of characters output. | |
1da177e4 LT |
557 | * |
558 | * This path is used to speed up block console writes, among other | |
559 | * things when processing blocks of output data. It handles only | |
560 | * the simple cases normally found and helps to generate blocks of | |
561 | * symbols for the console driver and thus improve performance. | |
562 | * | |
a88a69c9 JP |
563 | * Locking: output_lock to protect column state and space left |
564 | * (also, this is called from n_tty_write under the | |
565 | * tty layer write lock) | |
1da177e4 | 566 | */ |
4edf1827 | 567 | |
a88a69c9 JP |
568 | static ssize_t process_output_block(struct tty_struct *tty, |
569 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 570 | { |
53c5ee2c | 571 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 572 | int space; |
bbd20759 | 573 | int i; |
1da177e4 LT |
574 | const unsigned char *cp; |
575 | ||
bddc7152 | 576 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 577 | |
f34d7a5b | 578 | space = tty_write_room(tty); |
300a6204 | 579 | if (!space) { |
bddc7152 | 580 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 581 | return 0; |
a88a69c9 | 582 | } |
1da177e4 LT |
583 | if (nr > space) |
584 | nr = space; | |
585 | ||
586 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
587 | unsigned char c = *cp; |
588 | ||
589 | switch (c) { | |
1da177e4 LT |
590 | case '\n': |
591 | if (O_ONLRET(tty)) | |
53c5ee2c | 592 | ldata->column = 0; |
1da177e4 LT |
593 | if (O_ONLCR(tty)) |
594 | goto break_out; | |
ba2e68ac | 595 | ldata->canon_column = ldata->column; |
1da177e4 LT |
596 | break; |
597 | case '\r': | |
53c5ee2c | 598 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
599 | goto break_out; |
600 | if (O_OCRNL(tty)) | |
601 | goto break_out; | |
ba2e68ac | 602 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
603 | break; |
604 | case '\t': | |
605 | goto break_out; | |
606 | case '\b': | |
53c5ee2c JS |
607 | if (ldata->column > 0) |
608 | ldata->column--; | |
1da177e4 LT |
609 | break; |
610 | default: | |
a59c0d6f JP |
611 | if (!iscntrl(c)) { |
612 | if (O_OLCUC(tty)) | |
613 | goto break_out; | |
614 | if (!is_continuation(c, tty)) | |
53c5ee2c | 615 | ldata->column++; |
a59c0d6f | 616 | } |
1da177e4 LT |
617 | break; |
618 | } | |
619 | } | |
620 | break_out: | |
f34d7a5b | 621 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 622 | |
bddc7152 | 623 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
624 | return i; |
625 | } | |
626 | ||
a88a69c9 JP |
627 | /** |
628 | * process_echoes - write pending echo characters | |
629 | * @tty: terminal device | |
630 | * | |
631 | * Write previously buffered echo (and other ldisc-generated) | |
632 | * characters to the tty. | |
633 | * | |
634 | * Characters generated by the ldisc (including echoes) need to | |
635 | * be buffered because the driver's write buffer can fill during | |
636 | * heavy program output. Echoing straight to the driver will | |
637 | * often fail under these conditions, causing lost characters and | |
638 | * resulting mismatches of ldisc state information. | |
639 | * | |
640 | * Since the ldisc state must represent the characters actually sent | |
641 | * to the driver at the time of the write, operations like certain | |
642 | * changes in column state are also saved in the buffer and executed | |
643 | * here. | |
644 | * | |
645 | * A circular fifo buffer is used so that the most recent characters | |
646 | * are prioritized. Also, when control characters are echoed with a | |
647 | * prefixed "^", the pair is treated atomically and thus not separated. | |
648 | * | |
019ebdf9 | 649 | * Locking: callers must hold output_lock |
a88a69c9 JP |
650 | */ |
651 | ||
bc5b1ec5 | 652 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 653 | { |
53c5ee2c | 654 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 655 | int space, old_space; |
addaebcc | 656 | size_t tail; |
a88a69c9 | 657 | unsigned char c; |
a88a69c9 | 658 | |
bc5b1ec5 | 659 | old_space = space = tty_write_room(tty); |
a88a69c9 | 660 | |
addaebcc | 661 | tail = ldata->echo_tail; |
29c7c5ca | 662 | while (ldata->echo_commit != tail) { |
addaebcc | 663 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
664 | if (c == ECHO_OP_START) { |
665 | unsigned char op; | |
a88a69c9 JP |
666 | int no_space_left = 0; |
667 | ||
668 | /* | |
669 | * If the buffer byte is the start of a multi-byte | |
670 | * operation, get the next byte, which is either the | |
671 | * op code or a control character value. | |
672 | */ | |
addaebcc | 673 | op = echo_buf(ldata, tail + 1); |
300a6204 | 674 | |
a88a69c9 JP |
675 | switch (op) { |
676 | unsigned int num_chars, num_bs; | |
677 | ||
678 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 679 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
680 | |
681 | /* | |
682 | * Determine how many columns to go back | |
683 | * in order to erase the tab. | |
684 | * This depends on the number of columns | |
685 | * used by other characters within the tab | |
686 | * area. If this (modulo 8) count is from | |
687 | * the start of input rather than from a | |
688 | * previous tab, we offset by canon column. | |
689 | * Otherwise, tab spacing is normal. | |
690 | */ | |
691 | if (!(num_chars & 0x80)) | |
ba2e68ac | 692 | num_chars += ldata->canon_column; |
a88a69c9 JP |
693 | num_bs = 8 - (num_chars & 7); |
694 | ||
695 | if (num_bs > space) { | |
696 | no_space_left = 1; | |
697 | break; | |
698 | } | |
699 | space -= num_bs; | |
700 | while (num_bs--) { | |
701 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
702 | if (ldata->column > 0) |
703 | ldata->column--; | |
a88a69c9 | 704 | } |
addaebcc | 705 | tail += 3; |
a88a69c9 JP |
706 | break; |
707 | ||
708 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 709 | ldata->canon_column = ldata->column; |
addaebcc | 710 | tail += 2; |
a88a69c9 JP |
711 | break; |
712 | ||
713 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
714 | if (ldata->column > 0) |
715 | ldata->column--; | |
addaebcc | 716 | tail += 2; |
a88a69c9 JP |
717 | break; |
718 | ||
719 | case ECHO_OP_START: | |
720 | /* This is an escaped echo op start code */ | |
721 | if (!space) { | |
722 | no_space_left = 1; | |
723 | break; | |
724 | } | |
725 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 726 | ldata->column++; |
a88a69c9 | 727 | space--; |
addaebcc | 728 | tail += 2; |
a88a69c9 JP |
729 | break; |
730 | ||
731 | default: | |
a88a69c9 | 732 | /* |
62b26358 JP |
733 | * If the op is not a special byte code, |
734 | * it is a ctrl char tagged to be echoed | |
735 | * as "^X" (where X is the letter | |
736 | * representing the control char). | |
737 | * Note that we must ensure there is | |
738 | * enough space for the whole ctrl pair. | |
739 | * | |
a88a69c9 | 740 | */ |
62b26358 JP |
741 | if (space < 2) { |
742 | no_space_left = 1; | |
743 | break; | |
744 | } | |
745 | tty_put_char(tty, '^'); | |
746 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 747 | ldata->column += 2; |
62b26358 | 748 | space -= 2; |
addaebcc | 749 | tail += 2; |
a88a69c9 JP |
750 | } |
751 | ||
752 | if (no_space_left) | |
753 | break; | |
754 | } else { | |
582f5590 | 755 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
756 | int retval = do_output_char(c, tty, space); |
757 | if (retval < 0) | |
758 | break; | |
759 | space -= retval; | |
760 | } else { | |
761 | if (!space) | |
762 | break; | |
763 | tty_put_char(tty, c); | |
764 | space -= 1; | |
765 | } | |
addaebcc | 766 | tail += 1; |
a88a69c9 | 767 | } |
a88a69c9 JP |
768 | } |
769 | ||
cbfd0340 PH |
770 | /* If the echo buffer is nearly full (so that the possibility exists |
771 | * of echo overrun before the next commit), then discard enough | |
772 | * data at the tail to prevent a subsequent overrun */ | |
773 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 774 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 775 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
776 | tail += 3; |
777 | else | |
778 | tail += 2; | |
779 | } else | |
780 | tail++; | |
781 | } | |
782 | ||
addaebcc | 783 | ldata->echo_tail = tail; |
bc5b1ec5 | 784 | return old_space - space; |
019ebdf9 PH |
785 | } |
786 | ||
787 | static void commit_echoes(struct tty_struct *tty) | |
788 | { | |
789 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 790 | size_t nr, old, echoed; |
cbfd0340 PH |
791 | size_t head; |
792 | ||
793 | head = ldata->echo_head; | |
1075a6e2 | 794 | ldata->echo_mark = head; |
cbfd0340 PH |
795 | old = ldata->echo_commit - ldata->echo_tail; |
796 | ||
797 | /* Process committed echoes if the accumulated # of bytes | |
798 | * is over the threshold (and try again each time another | |
799 | * block is accumulated) */ | |
800 | nr = head - ldata->echo_tail; | |
801 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
802 | return; | |
a88a69c9 | 803 | |
019ebdf9 | 804 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 805 | ldata->echo_commit = head; |
bc5b1ec5 | 806 | echoed = __process_echoes(tty); |
bddc7152 | 807 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 808 | |
bc5b1ec5 | 809 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
810 | tty->ops->flush_chars(tty); |
811 | } | |
812 | ||
019ebdf9 | 813 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
814 | { |
815 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 816 | size_t echoed; |
17bd7907 | 817 | |
e2613be5 | 818 | if (ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
819 | return; |
820 | ||
821 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 822 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 823 | echoed = __process_echoes(tty); |
019ebdf9 PH |
824 | mutex_unlock(&ldata->output_lock); |
825 | ||
bc5b1ec5 | 826 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 827 | tty->ops->flush_chars(tty); |
17bd7907 PH |
828 | } |
829 | ||
1075a6e2 | 830 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
831 | static void flush_echoes(struct tty_struct *tty) |
832 | { | |
833 | struct n_tty_data *ldata = tty->disc_data; | |
834 | ||
39434abd PH |
835 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
836 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
837 | return; |
838 | ||
839 | mutex_lock(&ldata->output_lock); | |
840 | ldata->echo_commit = ldata->echo_head; | |
841 | __process_echoes(tty); | |
842 | mutex_unlock(&ldata->output_lock); | |
843 | } | |
844 | ||
a88a69c9 JP |
845 | /** |
846 | * add_echo_byte - add a byte to the echo buffer | |
847 | * @c: unicode byte to echo | |
57c94121 | 848 | * @ldata: n_tty data |
a88a69c9 JP |
849 | * |
850 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
851 | */ |
852 | ||
cbfd0340 | 853 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 854 | { |
addaebcc | 855 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
856 | } |
857 | ||
858 | /** | |
859 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 860 | * @ldata: n_tty data |
a88a69c9 JP |
861 | * |
862 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
863 | */ |
864 | ||
57c94121 | 865 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 866 | { |
57c94121 JS |
867 | add_echo_byte(ECHO_OP_START, ldata); |
868 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
869 | } |
870 | ||
871 | /** | |
872 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 873 | * @ldata: n_tty data |
a88a69c9 JP |
874 | * |
875 | * Add an operation to the echo buffer to set the canon column | |
876 | * to the current column. | |
a88a69c9 JP |
877 | */ |
878 | ||
57c94121 | 879 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 880 | { |
57c94121 JS |
881 | add_echo_byte(ECHO_OP_START, ldata); |
882 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
883 | } |
884 | ||
885 | /** | |
886 | * echo_erase_tab - add operation to erase a tab | |
887 | * @num_chars: number of character columns already used | |
888 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 889 | * @ldata: n_tty data |
a88a69c9 JP |
890 | * |
891 | * Add an operation to the echo buffer to erase a tab. | |
892 | * | |
893 | * Called by the eraser function, which knows how many character | |
894 | * columns have been used since either a previous tab or the start | |
895 | * of input. This information will be used later, along with | |
896 | * canon column (if applicable), to go back the correct number | |
897 | * of columns. | |
a88a69c9 JP |
898 | */ |
899 | ||
900 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 901 | struct n_tty_data *ldata) |
a88a69c9 | 902 | { |
57c94121 JS |
903 | add_echo_byte(ECHO_OP_START, ldata); |
904 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
905 | |
906 | /* We only need to know this modulo 8 (tab spacing) */ | |
907 | num_chars &= 7; | |
908 | ||
909 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
910 | if (after_tab) | |
911 | num_chars |= 0x80; | |
300a6204 | 912 | |
57c94121 | 913 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
914 | } |
915 | ||
916 | /** | |
917 | * echo_char_raw - echo a character raw | |
918 | * @c: unicode byte to echo | |
919 | * @tty: terminal device | |
920 | * | |
921 | * Echo user input back onto the screen. This must be called only when | |
922 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
923 | * | |
924 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
925 | */ |
926 | ||
57c94121 | 927 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 928 | { |
a88a69c9 | 929 | if (c == ECHO_OP_START) { |
57c94121 JS |
930 | add_echo_byte(ECHO_OP_START, ldata); |
931 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 932 | } else { |
57c94121 | 933 | add_echo_byte(c, ldata); |
a88a69c9 | 934 | } |
a88a69c9 | 935 | } |
1da177e4 | 936 | |
1da177e4 | 937 | /** |
a88a69c9 | 938 | * echo_char - echo a character |
1da177e4 LT |
939 | * @c: unicode byte to echo |
940 | * @tty: terminal device | |
941 | * | |
4edf1827 | 942 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 943 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 944 | * |
62b26358 JP |
945 | * This variant tags control characters to be echoed as "^X" |
946 | * (where X is the letter representing the control char). | |
1da177e4 LT |
947 | */ |
948 | ||
949 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
950 | { | |
bddc7152 JS |
951 | struct n_tty_data *ldata = tty->disc_data; |
952 | ||
a88a69c9 | 953 | if (c == ECHO_OP_START) { |
57c94121 JS |
954 | add_echo_byte(ECHO_OP_START, ldata); |
955 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 956 | } else { |
62b26358 | 957 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
958 | add_echo_byte(ECHO_OP_START, ldata); |
959 | add_echo_byte(c, ldata); | |
a88a69c9 | 960 | } |
1da177e4 LT |
961 | } |
962 | ||
17b82060 | 963 | /** |
a88a69c9 | 964 | * finish_erasing - complete erase |
57c94121 | 965 | * @ldata: n_tty data |
17b82060 | 966 | */ |
a88a69c9 | 967 | |
57c94121 | 968 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 969 | { |
53c5ee2c | 970 | if (ldata->erasing) { |
57c94121 | 971 | echo_char_raw('/', ldata); |
53c5ee2c | 972 | ldata->erasing = 0; |
1da177e4 LT |
973 | } |
974 | } | |
975 | ||
976 | /** | |
977 | * eraser - handle erase function | |
978 | * @c: character input | |
979 | * @tty: terminal device | |
980 | * | |
3a4fa0a2 | 981 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
982 | * present in the stream from the driver layer. Handles the complexities |
983 | * of UTF-8 multibyte symbols. | |
17b82060 | 984 | * |
6d76bd26 PH |
985 | * n_tty_receive_buf()/producer path: |
986 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 987 | */ |
4edf1827 | 988 | |
1da177e4 LT |
989 | static void eraser(unsigned char c, struct tty_struct *tty) |
990 | { | |
53c5ee2c | 991 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 992 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
993 | size_t head; |
994 | size_t cnt; | |
995 | int seen_alnums; | |
1da177e4 | 996 | |
ba2e68ac | 997 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 998 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
999 | return; |
1000 | } | |
1001 | if (c == ERASE_CHAR(tty)) | |
1002 | kill_type = ERASE; | |
1003 | else if (c == WERASE_CHAR(tty)) | |
1004 | kill_type = WERASE; | |
1005 | else { | |
1006 | if (!L_ECHO(tty)) { | |
ba2e68ac | 1007 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
1008 | return; |
1009 | } | |
1010 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 1011 | ldata->read_head = ldata->canon_head; |
57c94121 | 1012 | finish_erasing(ldata); |
1da177e4 LT |
1013 | echo_char(KILL_CHAR(tty), tty); |
1014 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
1015 | if (L_ECHOK(tty)) | |
57c94121 | 1016 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1017 | return; |
1018 | } | |
1019 | kill_type = KILL; | |
1020 | } | |
1021 | ||
1022 | seen_alnums = 0; | |
ba2e68ac JS |
1023 | while (ldata->read_head != ldata->canon_head) { |
1024 | head = ldata->read_head; | |
1da177e4 LT |
1025 | |
1026 | /* erase a single possibly multibyte character */ | |
1027 | do { | |
bc5a5e3f PH |
1028 | head--; |
1029 | c = read_buf(ldata, head); | |
ba2e68ac | 1030 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1031 | |
1032 | /* do not partially erase */ | |
1033 | if (is_continuation(c, tty)) | |
1034 | break; | |
1035 | ||
1036 | if (kill_type == WERASE) { | |
1037 | /* Equivalent to BSD's ALTWERASE. */ | |
1038 | if (isalnum(c) || c == '_') | |
1039 | seen_alnums++; | |
1040 | else if (seen_alnums) | |
1041 | break; | |
1042 | } | |
bc5a5e3f | 1043 | cnt = ldata->read_head - head; |
ba2e68ac | 1044 | ldata->read_head = head; |
1da177e4 LT |
1045 | if (L_ECHO(tty)) { |
1046 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1047 | if (!ldata->erasing) { |
57c94121 | 1048 | echo_char_raw('\\', ldata); |
53c5ee2c | 1049 | ldata->erasing = 1; |
1da177e4 LT |
1050 | } |
1051 | /* if cnt > 1, output a multi-byte character */ | |
1052 | echo_char(c, tty); | |
1053 | while (--cnt > 0) { | |
bc5a5e3f PH |
1054 | head++; |
1055 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1056 | echo_move_back_col(ldata); |
1da177e4 LT |
1057 | } |
1058 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1059 | echo_char(ERASE_CHAR(tty), tty); | |
1060 | } else if (c == '\t') { | |
a88a69c9 JP |
1061 | unsigned int num_chars = 0; |
1062 | int after_tab = 0; | |
bc5a5e3f | 1063 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1064 | |
1065 | /* | |
1066 | * Count the columns used for characters | |
1067 | * since the start of input or after a | |
1068 | * previous tab. | |
1069 | * This info is used to go back the correct | |
1070 | * number of columns. | |
1071 | */ | |
ba2e68ac | 1072 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1073 | tail--; |
1074 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1075 | if (c == '\t') { |
1076 | after_tab = 1; | |
1077 | break; | |
300a6204 | 1078 | } else if (iscntrl(c)) { |
1da177e4 | 1079 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1080 | num_chars += 2; |
1081 | } else if (!is_continuation(c, tty)) { | |
1082 | num_chars++; | |
1083 | } | |
1da177e4 | 1084 | } |
57c94121 | 1085 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1086 | } else { |
1087 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1088 | echo_char_raw('\b', ldata); |
1089 | echo_char_raw(' ', ldata); | |
1090 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1091 | } |
1092 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1093 | echo_char_raw('\b', ldata); |
1094 | echo_char_raw(' ', ldata); | |
1095 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1096 | } |
1097 | } | |
1098 | } | |
1099 | if (kill_type == ERASE) | |
1100 | break; | |
1101 | } | |
ba2e68ac | 1102 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1103 | finish_erasing(ldata); |
1da177e4 LT |
1104 | } |
1105 | ||
1106 | /** | |
1107 | * isig - handle the ISIG optio | |
1108 | * @sig: signal | |
1109 | * @tty: terminal | |
1da177e4 | 1110 | * |
8c985d18 PH |
1111 | * Called when a signal is being sent due to terminal input. |
1112 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1113 | * |
d2b6f447 PH |
1114 | * Performs input and output flush if !NOFLSH. In this context, the echo |
1115 | * buffer is 'output'. The signal is processed first to alert any current | |
1116 | * readers or writers to discontinue and exit their i/o loops. | |
1117 | * | |
8c985d18 | 1118 | * Locking: ctrl_lock |
1da177e4 | 1119 | */ |
4edf1827 | 1120 | |
3b19e032 | 1121 | static void __isig(int sig, struct tty_struct *tty) |
1da177e4 | 1122 | { |
8c985d18 PH |
1123 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1124 | if (tty_pgrp) { | |
1125 | kill_pgrp(tty_pgrp, sig, 1); | |
1126 | put_pid(tty_pgrp); | |
1da177e4 | 1127 | } |
3b19e032 | 1128 | } |
d2b6f447 | 1129 | |
3b19e032 PH |
1130 | static void isig(int sig, struct tty_struct *tty) |
1131 | { | |
1132 | struct n_tty_data *ldata = tty->disc_data; | |
1133 | ||
1134 | if (L_NOFLSH(tty)) { | |
1135 | /* signal only */ | |
1136 | __isig(sig, tty); | |
1137 | ||
1138 | } else { /* signal and flush */ | |
d2b6f447 PH |
1139 | up_read(&tty->termios_rwsem); |
1140 | down_write(&tty->termios_rwsem); | |
1141 | ||
3b19e032 PH |
1142 | __isig(sig, tty); |
1143 | ||
d2b6f447 PH |
1144 | /* clear echo buffer */ |
1145 | mutex_lock(&ldata->output_lock); | |
1146 | ldata->echo_head = ldata->echo_tail = 0; | |
1147 | ldata->echo_mark = ldata->echo_commit = 0; | |
1148 | mutex_unlock(&ldata->output_lock); | |
1149 | ||
1150 | /* clear output buffer */ | |
1151 | tty_driver_flush_buffer(tty); | |
1152 | ||
1153 | /* clear input buffer */ | |
1154 | reset_buffer_flags(tty->disc_data); | |
1155 | ||
1156 | /* notify pty master of flush */ | |
1157 | if (tty->link) | |
1158 | n_tty_packet_mode_flush(tty); | |
1159 | ||
1160 | up_write(&tty->termios_rwsem); | |
1161 | down_read(&tty->termios_rwsem); | |
1162 | } | |
1da177e4 LT |
1163 | } |
1164 | ||
1165 | /** | |
1166 | * n_tty_receive_break - handle break | |
1167 | * @tty: terminal | |
1168 | * | |
1169 | * An RS232 break event has been hit in the incoming bitstream. This | |
1170 | * can cause a variety of events depending upon the termios settings. | |
1171 | * | |
6d76bd26 PH |
1172 | * n_tty_receive_buf()/producer path: |
1173 | * caller holds non-exclusive termios_rwsem | |
6d76bd26 PH |
1174 | * |
1175 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1176 | */ |
4edf1827 | 1177 | |
4b293492 | 1178 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1179 | { |
57c94121 JS |
1180 | struct n_tty_data *ldata = tty->disc_data; |
1181 | ||
1da177e4 LT |
1182 | if (I_IGNBRK(tty)) |
1183 | return; | |
1184 | if (I_BRKINT(tty)) { | |
8c985d18 | 1185 | isig(SIGINT, tty); |
1da177e4 LT |
1186 | return; |
1187 | } | |
1188 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1189 | put_tty_queue('\377', ldata); |
1190 | put_tty_queue('\0', ldata); | |
1da177e4 | 1191 | } |
57c94121 | 1192 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1193 | } |
1194 | ||
1195 | /** | |
1196 | * n_tty_receive_overrun - handle overrun reporting | |
1197 | * @tty: terminal | |
1198 | * | |
1199 | * Data arrived faster than we could process it. While the tty | |
1200 | * driver has flagged this the bits that were missed are gone | |
1201 | * forever. | |
1202 | * | |
1203 | * Called from the receive_buf path so single threaded. Does not | |
1204 | * need locking as num_overrun and overrun_time are function | |
1205 | * private. | |
1206 | */ | |
4edf1827 | 1207 | |
4b293492 | 1208 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1209 | { |
53c5ee2c | 1210 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1211 | |
53c5ee2c JS |
1212 | ldata->num_overrun++; |
1213 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1214 | time_after(ldata->overrun_time, jiffies)) { | |
339f36ba | 1215 | tty_warn(tty, "%d input overrun(s)\n", ldata->num_overrun); |
53c5ee2c JS |
1216 | ldata->overrun_time = jiffies; |
1217 | ldata->num_overrun = 0; | |
1da177e4 LT |
1218 | } |
1219 | } | |
1220 | ||
1221 | /** | |
1222 | * n_tty_receive_parity_error - error notifier | |
1223 | * @tty: terminal device | |
1224 | * @c: character | |
1225 | * | |
1226 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1227 | * the error case if necessary. |
1228 | * | |
1229 | * n_tty_receive_buf()/producer path: | |
1230 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 1231 | */ |
4b293492 | 1232 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1233 | { |
57c94121 JS |
1234 | struct n_tty_data *ldata = tty->disc_data; |
1235 | ||
66528f90 PH |
1236 | if (I_INPCK(tty)) { |
1237 | if (I_IGNPAR(tty)) | |
1238 | return; | |
1239 | if (I_PARMRK(tty)) { | |
1240 | put_tty_queue('\377', ldata); | |
1241 | put_tty_queue('\0', ldata); | |
1242 | put_tty_queue(c, ldata); | |
1243 | } else | |
1244 | put_tty_queue('\0', ldata); | |
1245 | } else | |
57c94121 | 1246 | put_tty_queue(c, ldata); |
1da177e4 LT |
1247 | } |
1248 | ||
b0ac50be PH |
1249 | static void |
1250 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1251 | { | |
d2b6f447 | 1252 | isig(signal, tty); |
b0ac50be PH |
1253 | if (I_IXON(tty)) |
1254 | start_tty(tty); | |
1255 | if (L_ECHO(tty)) { | |
1256 | echo_char(c, tty); | |
1257 | commit_echoes(tty); | |
e2613be5 PH |
1258 | } else |
1259 | process_echoes(tty); | |
b0ac50be PH |
1260 | return; |
1261 | } | |
1262 | ||
1da177e4 LT |
1263 | /** |
1264 | * n_tty_receive_char - perform processing | |
1265 | * @tty: terminal device | |
1266 | * @c: character | |
1267 | * | |
1268 | * Process an individual character of input received from the driver. | |
4edf1827 | 1269 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1270 | * driver above. |
6d76bd26 PH |
1271 | * |
1272 | * n_tty_receive_buf()/producer path: | |
1273 | * caller holds non-exclusive termios_rwsem | |
1274 | * publishes canon_head if canonical mode is active | |
e60d27c4 PH |
1275 | * |
1276 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1277 | */ |
1278 | ||
e60d27c4 | 1279 | static int |
4b1f79c2 | 1280 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1281 | { |
53c5ee2c | 1282 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1283 | |
1da177e4 LT |
1284 | if (I_IXON(tty)) { |
1285 | if (c == START_CHAR(tty)) { | |
1286 | start_tty(tty); | |
e2613be5 | 1287 | process_echoes(tty); |
e60d27c4 | 1288 | return 0; |
1da177e4 LT |
1289 | } |
1290 | if (c == STOP_CHAR(tty)) { | |
1291 | stop_tty(tty); | |
e60d27c4 | 1292 | return 0; |
1da177e4 LT |
1293 | } |
1294 | } | |
575537b3 | 1295 | |
1da177e4 | 1296 | if (L_ISIG(tty)) { |
b0ac50be PH |
1297 | if (c == INTR_CHAR(tty)) { |
1298 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1299 | return 0; |
b0ac50be PH |
1300 | } else if (c == QUIT_CHAR(tty)) { |
1301 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1302 | return 0; |
b0ac50be PH |
1303 | } else if (c == SUSP_CHAR(tty)) { |
1304 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1305 | return 0; |
1da177e4 LT |
1306 | } |
1307 | } | |
575537b3 | 1308 | |
855df3c0 PH |
1309 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1310 | start_tty(tty); | |
1311 | process_echoes(tty); | |
1312 | } | |
1313 | ||
575537b3 JP |
1314 | if (c == '\r') { |
1315 | if (I_IGNCR(tty)) | |
e60d27c4 | 1316 | return 0; |
575537b3 JP |
1317 | if (I_ICRNL(tty)) |
1318 | c = '\n'; | |
1319 | } else if (c == '\n' && I_INLCR(tty)) | |
1320 | c = '\r'; | |
1321 | ||
53c5ee2c | 1322 | if (ldata->icanon) { |
1da177e4 LT |
1323 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1324 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1325 | eraser(c, tty); | |
17bd7907 | 1326 | commit_echoes(tty); |
e60d27c4 | 1327 | return 0; |
1da177e4 LT |
1328 | } |
1329 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1330 | ldata->lnext = 1; |
1da177e4 | 1331 | if (L_ECHO(tty)) { |
57c94121 | 1332 | finish_erasing(ldata); |
1da177e4 | 1333 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1334 | echo_char_raw('^', ldata); |
1335 | echo_char_raw('\b', ldata); | |
17bd7907 | 1336 | commit_echoes(tty); |
1da177e4 LT |
1337 | } |
1338 | } | |
e60d27c4 | 1339 | return 1; |
1da177e4 | 1340 | } |
e60d27c4 | 1341 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1342 | size_t tail = ldata->canon_head; |
1da177e4 | 1343 | |
57c94121 | 1344 | finish_erasing(ldata); |
1da177e4 | 1345 | echo_char(c, tty); |
57c94121 | 1346 | echo_char_raw('\n', ldata); |
ba2e68ac | 1347 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1348 | echo_char(read_buf(ldata, tail), tty); |
1349 | tail++; | |
1da177e4 | 1350 | } |
17bd7907 | 1351 | commit_echoes(tty); |
e60d27c4 | 1352 | return 0; |
1da177e4 LT |
1353 | } |
1354 | if (c == '\n') { | |
acc71bba | 1355 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1356 | echo_char_raw('\n', ldata); |
17bd7907 | 1357 | commit_echoes(tty); |
1da177e4 LT |
1358 | } |
1359 | goto handle_newline; | |
1360 | } | |
1361 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1362 | c = __DISABLED_CHAR; |
1363 | goto handle_newline; | |
1364 | } | |
1365 | if ((c == EOL_CHAR(tty)) || | |
1366 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1367 | /* | |
1368 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1369 | */ | |
1370 | if (L_ECHO(tty)) { | |
1da177e4 | 1371 | /* Record the column of first canon char. */ |
ba2e68ac | 1372 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1373 | echo_set_canon_col(ldata); |
1da177e4 | 1374 | echo_char(c, tty); |
17bd7907 | 1375 | commit_echoes(tty); |
1da177e4 LT |
1376 | } |
1377 | /* | |
1378 | * XXX does PARMRK doubling happen for | |
1379 | * EOL_CHAR and EOL2_CHAR? | |
1380 | */ | |
001ba923 | 1381 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
57c94121 | 1382 | put_tty_queue(c, ldata); |
1da177e4 | 1383 | |
4edf1827 | 1384 | handle_newline: |
bc5a5e3f | 1385 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1386 | put_tty_queue(c, ldata); |
70aca71f | 1387 | smp_store_release(&ldata->canon_head, ldata->read_head); |
1da177e4 | 1388 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
e81107d4 | 1389 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
e60d27c4 | 1390 | return 0; |
1da177e4 LT |
1391 | } |
1392 | } | |
4edf1827 | 1393 | |
acc71bba | 1394 | if (L_ECHO(tty)) { |
57c94121 | 1395 | finish_erasing(ldata); |
1da177e4 | 1396 | if (c == '\n') |
57c94121 | 1397 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1398 | else { |
1399 | /* Record the column of first canon char. */ | |
ba2e68ac | 1400 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1401 | echo_set_canon_col(ldata); |
1da177e4 LT |
1402 | echo_char(c, tty); |
1403 | } | |
17bd7907 | 1404 | commit_echoes(tty); |
1da177e4 LT |
1405 | } |
1406 | ||
001ba923 PH |
1407 | /* PARMRK doubling check */ |
1408 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
57c94121 | 1409 | put_tty_queue(c, ldata); |
1da177e4 | 1410 | |
57c94121 | 1411 | put_tty_queue(c, ldata); |
e60d27c4 | 1412 | return 0; |
4edf1827 | 1413 | } |
1da177e4 | 1414 | |
e60d27c4 PH |
1415 | static inline void |
1416 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1417 | { |
1418 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1419 | |
e60d27c4 PH |
1420 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1421 | start_tty(tty); | |
1422 | process_echoes(tty); | |
1423 | } | |
1424 | if (L_ECHO(tty)) { | |
1425 | finish_erasing(ldata); | |
1426 | /* Record the column of first canon char. */ | |
1427 | if (ldata->canon_head == ldata->read_head) | |
1428 | echo_set_canon_col(ldata); | |
1429 | echo_char(c, tty); | |
1430 | commit_echoes(tty); | |
4b1f79c2 | 1431 | } |
001ba923 PH |
1432 | /* PARMRK doubling check */ |
1433 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
e60d27c4 PH |
1434 | put_tty_queue(c, ldata); |
1435 | put_tty_queue(c, ldata); | |
1436 | } | |
4b1f79c2 | 1437 | |
eb3e4668 | 1438 | static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
e60d27c4 PH |
1439 | { |
1440 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1441 | } |
1442 | ||
7de971b0 PH |
1443 | static inline void |
1444 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1445 | { | |
1446 | struct n_tty_data *ldata = tty->disc_data; | |
1447 | ||
e60d27c4 PH |
1448 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1449 | start_tty(tty); | |
1450 | process_echoes(tty); | |
7de971b0 | 1451 | } |
e60d27c4 PH |
1452 | if (L_ECHO(tty)) { |
1453 | finish_erasing(ldata); | |
1454 | /* Record the column of first canon char. */ | |
1455 | if (ldata->canon_head == ldata->read_head) | |
1456 | echo_set_canon_col(ldata); | |
1457 | echo_char(c, tty); | |
1458 | commit_echoes(tty); | |
1459 | } | |
1460 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1461 | } |
1462 | ||
8dc4b25d | 1463 | static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) |
ad0cc7ba PH |
1464 | { |
1465 | if (I_ISTRIP(tty)) | |
1466 | c &= 0x7f; | |
1467 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1468 | c = tolower(c); | |
1469 | ||
1470 | if (I_IXON(tty)) { | |
1471 | if (c == STOP_CHAR(tty)) | |
1472 | stop_tty(tty); | |
1473 | else if (c == START_CHAR(tty) || | |
1474 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1475 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1476 | c != SUSP_CHAR(tty))) { | |
1477 | start_tty(tty); | |
1478 | process_echoes(tty); | |
1479 | } | |
1480 | } | |
1481 | } | |
1482 | ||
d2f8d7ab PH |
1483 | static void |
1484 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1485 | { | |
d2f8d7ab PH |
1486 | switch (flag) { |
1487 | case TTY_BREAK: | |
1488 | n_tty_receive_break(tty); | |
1489 | break; | |
1490 | case TTY_PARITY: | |
1491 | case TTY_FRAME: | |
1492 | n_tty_receive_parity_error(tty, c); | |
1493 | break; | |
1494 | case TTY_OVERRUN: | |
1495 | n_tty_receive_overrun(tty); | |
1496 | break; | |
1497 | default: | |
339f36ba | 1498 | tty_err(tty, "unknown flag %d\n", flag); |
d2f8d7ab PH |
1499 | break; |
1500 | } | |
1501 | } | |
1502 | ||
e60d27c4 PH |
1503 | static void |
1504 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1505 | { | |
1506 | struct n_tty_data *ldata = tty->disc_data; | |
1507 | ||
1508 | ldata->lnext = 0; | |
1509 | if (likely(flag == TTY_NORMAL)) { | |
1510 | if (I_ISTRIP(tty)) | |
1511 | c &= 0x7f; | |
1512 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1513 | c = tolower(c); | |
1514 | n_tty_receive_char(tty, c); | |
1515 | } else | |
1516 | n_tty_receive_char_flagged(tty, c, flag); | |
1517 | } | |
1518 | ||
4a23a4df PH |
1519 | static void |
1520 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1521 | char *fp, int count) | |
1522 | { | |
1523 | struct n_tty_data *ldata = tty->disc_data; | |
1524 | size_t n, head; | |
1525 | ||
1526 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1527 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1528 | memcpy(read_buf_addr(ldata, head), cp, n); |
1529 | ldata->read_head += n; | |
1530 | cp += n; | |
1531 | count -= n; | |
1532 | ||
1533 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1534 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1535 | memcpy(read_buf_addr(ldata, head), cp, n); |
1536 | ldata->read_head += n; | |
1537 | } | |
1538 | ||
554117bd PH |
1539 | static void |
1540 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1541 | char *fp, int count) | |
1542 | { | |
1543 | struct n_tty_data *ldata = tty->disc_data; | |
1544 | char flag = TTY_NORMAL; | |
1545 | ||
1546 | while (count--) { | |
1547 | if (fp) | |
1548 | flag = *fp++; | |
1549 | if (likely(flag == TTY_NORMAL)) | |
1550 | put_tty_queue(*cp++, ldata); | |
1551 | else | |
1552 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1553 | } | |
1554 | } | |
1555 | ||
ad0cc7ba PH |
1556 | static void |
1557 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1558 | char *fp, int count) | |
1559 | { | |
1560 | char flag = TTY_NORMAL; | |
1561 | ||
1562 | while (count--) { | |
1563 | if (fp) | |
1564 | flag = *fp++; | |
1565 | if (likely(flag == TTY_NORMAL)) | |
1566 | n_tty_receive_char_closing(tty, *cp++); | |
1567 | else | |
1568 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1569 | } | |
1570 | } | |
1571 | ||
7d88d637 PH |
1572 | static void |
1573 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1574 | char *fp, int count) |
1575 | { | |
1576 | struct n_tty_data *ldata = tty->disc_data; | |
1577 | char flag = TTY_NORMAL; | |
1578 | ||
1579 | while (count--) { | |
1580 | if (fp) | |
1581 | flag = *fp++; | |
1582 | if (likely(flag == TTY_NORMAL)) { | |
1583 | unsigned char c = *cp++; | |
1584 | ||
1585 | if (I_ISTRIP(tty)) | |
1586 | c &= 0x7f; | |
1587 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1588 | c = tolower(c); | |
1589 | if (L_EXTPROC(tty)) { | |
1590 | put_tty_queue(c, ldata); | |
1591 | continue; | |
1592 | } | |
e60d27c4 PH |
1593 | if (!test_bit(c, ldata->char_map)) |
1594 | n_tty_receive_char_inline(tty, c); | |
1595 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1596 | if (fp) | |
1597 | flag = *fp++; | |
1598 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1599 | count--; | |
1600 | } | |
6baad008 PH |
1601 | } else |
1602 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1603 | } | |
1604 | } | |
1605 | ||
1606 | static void | |
1607 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1608 | char *fp, int count) | |
7d88d637 | 1609 | { |
e60d27c4 | 1610 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1611 | char flag = TTY_NORMAL; |
1612 | ||
1613 | while (count--) { | |
1614 | if (fp) | |
1615 | flag = *fp++; | |
e60d27c4 PH |
1616 | if (likely(flag == TTY_NORMAL)) { |
1617 | unsigned char c = *cp++; | |
1618 | ||
1619 | if (!test_bit(c, ldata->char_map)) | |
1620 | n_tty_receive_char_fast(tty, c); | |
1621 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1622 | if (fp) | |
1623 | flag = *fp++; | |
1624 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1625 | count--; | |
1626 | } | |
1627 | } else | |
7d88d637 PH |
1628 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1629 | } | |
1630 | } | |
1631 | ||
24a89d1c PH |
1632 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1633 | char *fp, int count) | |
1da177e4 | 1634 | { |
53c5ee2c | 1635 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1636 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1637 | |
4a23a4df PH |
1638 | if (ldata->real_raw) |
1639 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1640 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1641 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1642 | else if (tty->closing && !L_EXTPROC(tty)) |
1643 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1644 | else { |
e60d27c4 PH |
1645 | if (ldata->lnext) { |
1646 | char flag = TTY_NORMAL; | |
1647 | ||
1648 | if (fp) | |
1649 | flag = *fp++; | |
1650 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1651 | count--; | |
1652 | } | |
1653 | ||
7de971b0 | 1654 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1655 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1656 | else | |
1657 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1658 | |
1659 | flush_echoes(tty); | |
f34d7a5b AC |
1660 | if (tty->ops->flush_chars) |
1661 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1662 | } |
1663 | ||
70aca71f PH |
1664 | if (ldata->icanon && !L_EXTPROC(tty)) |
1665 | return; | |
1666 | ||
1667 | /* publish read_head to consumer */ | |
1668 | smp_store_release(&ldata->commit_head, ldata->read_head); | |
1669 | ||
1670 | if ((read_cnt(ldata) >= ldata->minimum_to_wake) || L_EXTPROC(tty)) { | |
1da177e4 | 1671 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
e81107d4 | 1672 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 | 1673 | } |
1da177e4 LT |
1674 | } |
1675 | ||
fb5ef9e7 PH |
1676 | /** |
1677 | * n_tty_receive_buf_common - process input | |
1678 | * @tty: device to receive input | |
1679 | * @cp: input chars | |
1680 | * @fp: flags for each char (if NULL, all chars are TTY_NORMAL) | |
1681 | * @count: number of input chars in @cp | |
1682 | * | |
1683 | * Called by the terminal driver when a block of characters has | |
1684 | * been received. This function must be called from soft contexts | |
1685 | * not from interrupt context. The driver is responsible for making | |
1686 | * calls one at a time and in order (or using flush_to_ldisc) | |
1687 | * | |
1688 | * Returns the # of input chars from @cp which were processed. | |
1689 | * | |
1690 | * In canonical mode, the maximum line length is 4096 chars (including | |
1691 | * the line termination char); lines longer than 4096 chars are | |
1692 | * truncated. After 4095 chars, input data is still processed but | |
1693 | * not stored. Overflow processing ensures the tty can always | |
1694 | * receive more input until at least one line can be read. | |
1695 | * | |
1696 | * In non-canonical mode, the read buffer will only accept 4095 chars; | |
1697 | * this provides the necessary space for a newline char if the input | |
1698 | * mode is switched to canonical. | |
1699 | * | |
1700 | * Note it is possible for the read buffer to _contain_ 4096 chars | |
1701 | * in non-canonical mode: the read buffer could already contain the | |
1702 | * maximum canon line of 4096 chars when the mode is switched to | |
1703 | * non-canonical. | |
1704 | * | |
1705 | * n_tty_receive_buf()/producer path: | |
1706 | * claims non-exclusive termios_rwsem | |
1707 | * publishes commit_head or canon_head | |
1708 | */ | |
5c32d123 PH |
1709 | static int |
1710 | n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, | |
1711 | char *fp, int count, int flow) | |
24a89d1c PH |
1712 | { |
1713 | struct n_tty_data *ldata = tty->disc_data; | |
fb5ef9e7 | 1714 | int room, n, rcvd = 0, overflow; |
24a89d1c | 1715 | |
9356b535 PH |
1716 | down_read(&tty->termios_rwsem); |
1717 | ||
19e2ad6a | 1718 | while (1) { |
70aca71f | 1719 | /* |
06c49f9f PH |
1720 | * When PARMRK is set, each input char may take up to 3 chars |
1721 | * in the read buf; reduce the buffer space avail by 3x | |
70aca71f PH |
1722 | * |
1723 | * If we are doing input canonicalization, and there are no | |
1724 | * pending newlines, let characters through without limit, so | |
1725 | * that erase characters will be handled. Other excess | |
1726 | * characters will be beeped. | |
1727 | * | |
1728 | * paired with store in *_copy_from_read_buf() -- guarantees | |
1729 | * the consumer has loaded the data in read_buf up to the new | |
1730 | * read_tail (so this producer will not overwrite unread data) | |
1731 | */ | |
1732 | size_t tail = smp_load_acquire(&ldata->read_tail); | |
70aca71f | 1733 | |
fb5ef9e7 | 1734 | room = N_TTY_BUF_SIZE - (ldata->read_head - tail); |
70aca71f | 1735 | if (I_PARMRK(tty)) |
fb5ef9e7 PH |
1736 | room = (room + 2) / 3; |
1737 | room--; | |
1738 | if (room <= 0) { | |
1739 | overflow = ldata->icanon && ldata->canon_head == tail; | |
1740 | if (overflow && room < 0) | |
1741 | ldata->read_head--; | |
1742 | room = overflow; | |
1743 | ldata->no_room = flow && !room; | |
1744 | } else | |
1745 | overflow = 0; | |
70aca71f | 1746 | |
19e2ad6a | 1747 | n = min(count, room); |
fb5ef9e7 | 1748 | if (!n) |
19e2ad6a | 1749 | break; |
fb5ef9e7 PH |
1750 | |
1751 | /* ignore parity errors if handling overflow */ | |
1752 | if (!overflow || !fp || *fp != TTY_PARITY) | |
1753 | __receive_buf(tty, cp, fp, n); | |
1754 | ||
19e2ad6a PH |
1755 | cp += n; |
1756 | if (fp) | |
1757 | fp += n; | |
1758 | count -= n; | |
1759 | rcvd += n; | |
4a23a4df | 1760 | } |
24a89d1c | 1761 | |
19e2ad6a | 1762 | tty->receive_room = room; |
fb5ef9e7 PH |
1763 | |
1764 | /* Unthrottle if handling overflow on pty */ | |
1765 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { | |
1766 | if (overflow) { | |
1767 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1768 | tty_unthrottle_safe(tty); | |
1769 | __tty_set_flow_change(tty, 0); | |
1770 | } | |
1771 | } else | |
1772 | n_tty_check_throttle(tty); | |
1773 | ||
9356b535 PH |
1774 | up_read(&tty->termios_rwsem); |
1775 | ||
19e2ad6a | 1776 | return rcvd; |
24a89d1c PH |
1777 | } |
1778 | ||
5c32d123 PH |
1779 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1780 | char *fp, int count) | |
1781 | { | |
1782 | n_tty_receive_buf_common(tty, cp, fp, count, 0); | |
1783 | } | |
1784 | ||
1785 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1786 | char *fp, int count) | |
1787 | { | |
1788 | return n_tty_receive_buf_common(tty, cp, fp, count, 1); | |
1789 | } | |
1790 | ||
1da177e4 LT |
1791 | int is_ignored(int sig) |
1792 | { | |
1793 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1794 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1795 | } |
1796 | ||
1797 | /** | |
1798 | * n_tty_set_termios - termios data changed | |
1799 | * @tty: terminal | |
1800 | * @old: previous data | |
1801 | * | |
1802 | * Called by the tty layer when the user changes termios flags so | |
1803 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1804 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1805 | * guaranteed that this function will not be re-entered or in progress |
1806 | * when the ldisc is closed. | |
17b82060 | 1807 | * |
6a1c0680 | 1808 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1809 | */ |
4edf1827 AC |
1810 | |
1811 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1812 | { |
53c5ee2c | 1813 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1814 | |
c786f74e | 1815 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { |
3fe780b3 | 1816 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1817 | ldata->line_start = ldata->read_tail; |
1818 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1819 | ldata->canon_head = ldata->read_tail; | |
1820 | ldata->push = 0; | |
1821 | } else { | |
1822 | set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), | |
1823 | ldata->read_flags); | |
1824 | ldata->canon_head = ldata->read_head; | |
1825 | ldata->push = 1; | |
1826 | } | |
70aca71f | 1827 | ldata->commit_head = ldata->read_head; |
53c5ee2c | 1828 | ldata->erasing = 0; |
6f9b028a | 1829 | ldata->lnext = 0; |
47afa7a5 AC |
1830 | } |
1831 | ||
53c5ee2c | 1832 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1833 | |
1da177e4 LT |
1834 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1835 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1836 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1837 | I_PARMRK(tty)) { | |
1bb9d562 | 1838 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1839 | |
1840 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1841 | set_bit('\r', ldata->char_map); |
1da177e4 | 1842 | if (I_INLCR(tty)) |
1bb9d562 | 1843 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1844 | |
1845 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1846 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1847 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1848 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1849 | set_bit('\n', ldata->char_map); | |
1850 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1851 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1852 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1853 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1854 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1855 | if (L_ECHO(tty)) |
1856 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1857 | ldata->char_map); |
1da177e4 LT |
1858 | } |
1859 | } | |
1860 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1861 | set_bit(START_CHAR(tty), ldata->char_map); |
1862 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1863 | } |
1864 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1865 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1866 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1867 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1868 | } |
1bb9d562 | 1869 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1870 | ldata->raw = 0; |
1871 | ldata->real_raw = 0; | |
1da177e4 | 1872 | } else { |
53c5ee2c | 1873 | ldata->raw = 1; |
1da177e4 LT |
1874 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1875 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1876 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1877 | ldata->real_raw = 1; |
1da177e4 | 1878 | else |
53c5ee2c | 1879 | ldata->real_raw = 0; |
1da177e4 | 1880 | } |
dab73b4e WY |
1881 | /* |
1882 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1883 | * been stopped by STOP_CHAR(tty) before it. | |
1884 | */ | |
e2613be5 | 1885 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { |
dab73b4e | 1886 | start_tty(tty); |
e2613be5 PH |
1887 | process_echoes(tty); |
1888 | } | |
dab73b4e | 1889 | |
f34d7a5b | 1890 | /* The termios change make the tty ready for I/O */ |
e81107d4 KT |
1891 | wake_up_interruptible(&tty->write_wait); |
1892 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1893 | } |
1894 | ||
1895 | /** | |
1896 | * n_tty_close - close the ldisc for this tty | |
1897 | * @tty: device | |
1898 | * | |
4edf1827 AC |
1899 | * Called from the terminal layer when this line discipline is |
1900 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1901 | * discipline change. The function will not be called while other |
1902 | * ldisc methods are in progress. | |
1903 | */ | |
4edf1827 | 1904 | |
1da177e4 LT |
1905 | static void n_tty_close(struct tty_struct *tty) |
1906 | { | |
70ece7a7 JS |
1907 | struct n_tty_data *ldata = tty->disc_data; |
1908 | ||
79901317 PH |
1909 | if (tty->link) |
1910 | n_tty_packet_mode_flush(tty); | |
1911 | ||
20bafb3d | 1912 | vfree(ldata); |
70ece7a7 | 1913 | tty->disc_data = NULL; |
1da177e4 LT |
1914 | } |
1915 | ||
1916 | /** | |
1917 | * n_tty_open - open an ldisc | |
1918 | * @tty: terminal to open | |
1919 | * | |
4edf1827 | 1920 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1921 | * terminal device. Can sleep. Called serialized so that no |
1922 | * other events will occur in parallel. No further open will occur | |
1923 | * until a close. | |
1924 | */ | |
1925 | ||
1926 | static int n_tty_open(struct tty_struct *tty) | |
1927 | { | |
70ece7a7 JS |
1928 | struct n_tty_data *ldata; |
1929 | ||
20bafb3d PH |
1930 | /* Currently a malloc failure here can panic */ |
1931 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1932 | if (!ldata) |
1933 | goto err; | |
1934 | ||
53c5ee2c | 1935 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1936 | mutex_init(&ldata->atomic_read_lock); |
1937 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1938 | |
70ece7a7 | 1939 | tty->disc_data = ldata; |
b66f4fa5 | 1940 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1941 | ldata->column = 0; |
20bafb3d | 1942 | ldata->canon_column = 0; |
f6c8dbe6 | 1943 | ldata->minimum_to_wake = 1; |
20bafb3d PH |
1944 | ldata->num_overrun = 0; |
1945 | ldata->no_room = 0; | |
1946 | ldata->lnext = 0; | |
1da177e4 | 1947 | tty->closing = 0; |
b66f4fa5 PH |
1948 | /* indicate buffer work may resume */ |
1949 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1950 | n_tty_set_termios(tty, NULL); | |
1951 | tty_unthrottle(tty); | |
70ece7a7 | 1952 | |
1da177e4 | 1953 | return 0; |
70ece7a7 | 1954 | err: |
b91939f5 | 1955 | return -ENOMEM; |
1da177e4 LT |
1956 | } |
1957 | ||
eafbe67f | 1958 | static inline int input_available_p(struct tty_struct *tty, int poll) |
1da177e4 | 1959 | { |
53c5ee2c | 1960 | struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1961 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1962 | |
25e8d0ed PH |
1963 | if (ldata->icanon && !L_EXTPROC(tty)) |
1964 | return ldata->canon_head != ldata->read_tail; | |
1965 | else | |
70aca71f | 1966 | return ldata->commit_head - ldata->read_tail >= amt; |
1da177e4 LT |
1967 | } |
1968 | ||
1a48632f PH |
1969 | static inline int check_other_done(struct tty_struct *tty) |
1970 | { | |
1971 | int done = test_bit(TTY_OTHER_DONE, &tty->flags); | |
1972 | if (done) { | |
1973 | /* paired with cmpxchg() in check_other_closed(); ensures | |
1974 | * read buffer head index is not stale | |
1975 | */ | |
1976 | smp_mb__after_atomic(); | |
1977 | } | |
1978 | return done; | |
1979 | } | |
1980 | ||
1da177e4 | 1981 | /** |
bbd20759 | 1982 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1983 | * @tty: terminal device |
1984 | * @b: user data | |
1985 | * @nr: size of data | |
1986 | * | |
11a96d18 | 1987 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1988 | * ICANON is off; it copies characters straight from the tty queue to |
1989 | * user space directly. It can be profitably called twice; once to | |
1990 | * drain the space from the tail pointer to the (physical) end of the | |
1991 | * buffer, and once to drain the space from the (physical) beginning of | |
1992 | * the buffer to head pointer. | |
1993 | * | |
bddc7152 | 1994 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1995 | * |
6d76bd26 PH |
1996 | * n_tty_read()/consumer path: |
1997 | * caller holds non-exclusive termios_rwsem | |
1998 | * read_tail published | |
1da177e4 | 1999 | */ |
4edf1827 | 2000 | |
33f0f88f | 2001 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
2002 | unsigned char __user **b, |
2003 | size_t *nr) | |
2004 | ||
2005 | { | |
53c5ee2c | 2006 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2007 | int retval; |
2008 | size_t n; | |
3fa10cc8 | 2009 | bool is_eof; |
70aca71f | 2010 | size_t head = smp_load_acquire(&ldata->commit_head); |
bc5a5e3f | 2011 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
2012 | |
2013 | retval = 0; | |
70aca71f | 2014 | n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail); |
1da177e4 | 2015 | n = min(*nr, n); |
1da177e4 | 2016 | if (n) { |
e661cf70 PH |
2017 | const unsigned char *from = read_buf_addr(ldata, tail); |
2018 | retval = copy_to_user(*b, from, n); | |
1da177e4 | 2019 | n -= retval; |
e661cf70 PH |
2020 | is_eof = n == 1 && *from == EOF_CHAR(tty); |
2021 | tty_audit_add_data(tty, from, n, ldata->icanon); | |
70aca71f | 2022 | smp_store_release(&ldata->read_tail, ldata->read_tail + n); |
26df6d13 | 2023 | /* Turn single EOF into zero-length read */ |
70aca71f PH |
2024 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && |
2025 | (head == ldata->read_tail)) | |
3fa10cc8 | 2026 | n = 0; |
1da177e4 LT |
2027 | *b += n; |
2028 | *nr -= n; | |
2029 | } | |
2030 | return retval; | |
2031 | } | |
2032 | ||
88bb0de3 | 2033 | /** |
32f13521 | 2034 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
2035 | * @tty: terminal device |
2036 | * @b: user data | |
2037 | * @nr: size of data | |
2038 | * | |
2039 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
2040 | * it copies one line of input up to and including the line-delimiting |
2041 | * character into the user-space buffer. | |
88bb0de3 | 2042 | * |
4d0ed182 PH |
2043 | * NB: When termios is changed from non-canonical to canonical mode and |
2044 | * the read buffer contains data, n_tty_set_termios() simulates an EOF | |
2045 | * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. | |
2046 | * This causes data already processed as input to be immediately available | |
2047 | * as input although a newline has not been received. | |
2048 | * | |
88bb0de3 | 2049 | * Called under the atomic_read_lock mutex |
6d76bd26 PH |
2050 | * |
2051 | * n_tty_read()/consumer path: | |
2052 | * caller holds non-exclusive termios_rwsem | |
2053 | * read_tail published | |
88bb0de3 PH |
2054 | */ |
2055 | ||
32f13521 PH |
2056 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
2057 | unsigned char __user **b, | |
2058 | size_t *nr) | |
88bb0de3 PH |
2059 | { |
2060 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 2061 | size_t n, size, more, c; |
bc5a5e3f PH |
2062 | size_t eol; |
2063 | size_t tail; | |
2064 | int ret, found = 0; | |
88bb0de3 PH |
2065 | |
2066 | /* N.B. avoid overrun if nr == 0 */ | |
ac8f3bf8 | 2067 | if (!*nr) |
32f13521 | 2068 | return 0; |
88bb0de3 | 2069 | |
ac8f3bf8 PH |
2070 | n = min(*nr + 1, smp_load_acquire(&ldata->canon_head) - ldata->read_tail); |
2071 | ||
bc5a5e3f | 2072 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
2073 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
2074 | ||
bc5a5e3f | 2075 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2076 | __func__, *nr, tail, n, size); |
2077 | ||
2078 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2079 | more = n - (size - tail); | |
2080 | if (eol == N_TTY_BUF_SIZE && more) { | |
2081 | /* scan wrapped without finding set bit */ | |
2082 | eol = find_next_bit(ldata->read_flags, more, 0); | |
b985e9e3 PH |
2083 | found = eol != more; |
2084 | } else | |
2085 | found = eol != size; | |
32f13521 | 2086 | |
c77569d2 | 2087 | n = eol - tail; |
da555db6 MT |
2088 | if (n > N_TTY_BUF_SIZE) |
2089 | n += N_TTY_BUF_SIZE; | |
ac8f3bf8 | 2090 | c = n + found; |
32f13521 | 2091 | |
ac8f3bf8 PH |
2092 | if (!found || read_buf(ldata, eol) != __DISABLED_CHAR) { |
2093 | c = min(*nr, c); | |
2094 | n = c; | |
40d5e090 | 2095 | } |
32f13521 | 2096 | |
679e7c29 PH |
2097 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu tail:%zu more:%zu\n", |
2098 | __func__, eol, found, n, c, tail, more); | |
32f13521 | 2099 | |
679e7c29 | 2100 | ret = tty_copy_to_user(tty, *b, tail, n); |
32f13521 PH |
2101 | if (ret) |
2102 | return -EFAULT; | |
2103 | *b += n; | |
2104 | *nr -= n; | |
2105 | ||
a73d3d69 | 2106 | if (found) |
6d76bd26 | 2107 | clear_bit(eol, ldata->read_flags); |
70aca71f | 2108 | smp_store_release(&ldata->read_tail, ldata->read_tail + c); |
88bb0de3 | 2109 | |
40d5e090 | 2110 | if (found) { |
4d0ed182 PH |
2111 | if (!ldata->push) |
2112 | ldata->line_start = ldata->read_tail; | |
2113 | else | |
2114 | ldata->push = 0; | |
32f13521 | 2115 | tty_audit_push(tty); |
40d5e090 | 2116 | } |
ac8f3bf8 | 2117 | return 0; |
88bb0de3 PH |
2118 | } |
2119 | ||
cc4191dc | 2120 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2121 | size_t, loff_t *); |
1da177e4 LT |
2122 | |
2123 | /** | |
2124 | * job_control - check job control | |
2125 | * @tty: tty | |
2126 | * @file: file handle | |
2127 | * | |
2128 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2129 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2130 | * error code if action should be taken. |
04f378b1 | 2131 | * |
01a5e440 PH |
2132 | * Locking: redirected write test is safe |
2133 | * current->signal->tty check is safe | |
2134 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2135 | */ |
4edf1827 | 2136 | |
1da177e4 LT |
2137 | static int job_control(struct tty_struct *tty, struct file *file) |
2138 | { | |
2139 | /* Job control check -- must be done at start and after | |
2140 | every sleep (POSIX.1 7.1.1.4). */ | |
2141 | /* NOTE: not yet done after every sleep pending a thorough | |
2142 | check of the logic of this change. -- jlc */ | |
2143 | /* don't stop on /dev/console */ | |
2812d9e9 | 2144 | if (file->f_op->write == redirected_tty_write) |
01a5e440 PH |
2145 | return 0; |
2146 | ||
2812d9e9 | 2147 | return __tty_check_change(tty, SIGTTIN); |
1da177e4 | 2148 | } |
4edf1827 | 2149 | |
1da177e4 LT |
2150 | |
2151 | /** | |
11a96d18 | 2152 | * n_tty_read - read function for tty |
1da177e4 LT |
2153 | * @tty: tty device |
2154 | * @file: file object | |
2155 | * @buf: userspace buffer pointer | |
2156 | * @nr: size of I/O | |
2157 | * | |
2158 | * Perform reads for the line discipline. We are guaranteed that the | |
2159 | * line discipline will not be closed under us but we may get multiple | |
2160 | * parallel readers and must handle this ourselves. We may also get | |
2161 | * a hangup. Always called in user context, may sleep. | |
2162 | * | |
2163 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2164 | * |
2165 | * n_tty_read()/consumer path: | |
2166 | * claims non-exclusive termios_rwsem | |
2167 | * publishes read_tail | |
1da177e4 | 2168 | */ |
4edf1827 | 2169 | |
11a96d18 | 2170 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2171 | unsigned char __user *buf, size_t nr) |
2172 | { | |
53c5ee2c | 2173 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 2174 | unsigned char __user *b = buf; |
97d9e28d | 2175 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1a48632f | 2176 | int c, done; |
1da177e4 LT |
2177 | int minimum, time; |
2178 | ssize_t retval = 0; | |
1da177e4 | 2179 | long timeout; |
04f378b1 | 2180 | int packet; |
2c5dc464 | 2181 | size_t tail; |
1da177e4 | 2182 | |
1da177e4 | 2183 | c = job_control(tty, file); |
4edf1827 | 2184 | if (c < 0) |
1da177e4 | 2185 | return c; |
4edf1827 | 2186 | |
aefceaf4 PH |
2187 | /* |
2188 | * Internal serialization of reads. | |
2189 | */ | |
2190 | if (file->f_flags & O_NONBLOCK) { | |
2191 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2192 | return -EAGAIN; | |
2193 | } else { | |
2194 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2195 | return -ERESTARTSYS; | |
2196 | } | |
2197 | ||
9356b535 PH |
2198 | down_read(&tty->termios_rwsem); |
2199 | ||
1da177e4 LT |
2200 | minimum = time = 0; |
2201 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2202 | if (!ldata->icanon) { |
1da177e4 LT |
2203 | minimum = MIN_CHAR(tty); |
2204 | if (minimum) { | |
a6e54319 | 2205 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2206 | if (time) |
f6c8dbe6 | 2207 | ldata->minimum_to_wake = 1; |
1da177e4 | 2208 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
2209 | (ldata->minimum_to_wake > minimum)) |
2210 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 2211 | } else { |
a6e54319 | 2212 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2213 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2214 | } |
2215 | } | |
2216 | ||
04f378b1 | 2217 | packet = tty->packet; |
2c5dc464 | 2218 | tail = ldata->read_tail; |
1da177e4 LT |
2219 | |
2220 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2221 | while (nr) { |
2222 | /* First test for status change. */ | |
04f378b1 | 2223 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2224 | unsigned char cs; |
2225 | if (b != buf) | |
2226 | break; | |
6054c16e | 2227 | spin_lock_irq(&tty->link->ctrl_lock); |
1da177e4 LT |
2228 | cs = tty->link->ctrl_status; |
2229 | tty->link->ctrl_status = 0; | |
6054c16e | 2230 | spin_unlock_irq(&tty->link->ctrl_lock); |
522ed776 | 2231 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2232 | retval = -EFAULT; |
2233 | b--; | |
2234 | break; | |
2235 | } | |
2236 | nr--; | |
2237 | break; | |
2238 | } | |
4edf1827 | 2239 | |
f6c8dbe6 | 2240 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2241 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2242 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2243 | |
1a48632f PH |
2244 | done = check_other_done(tty); |
2245 | ||
1da177e4 | 2246 | if (!input_available_p(tty, 0)) { |
1a48632f | 2247 | if (done) { |
52bce7f8 PH |
2248 | retval = -EIO; |
2249 | break; | |
f8747d4a | 2250 | } |
52bce7f8 PH |
2251 | if (tty_hung_up_p(file)) |
2252 | break; | |
2253 | if (!timeout) | |
2254 | break; | |
2255 | if (file->f_flags & O_NONBLOCK) { | |
2256 | retval = -EAGAIN; | |
1da177e4 LT |
2257 | break; |
2258 | } | |
52bce7f8 PH |
2259 | if (signal_pending(current)) { |
2260 | retval = -ERESTARTSYS; | |
2261 | break; | |
2262 | } | |
52bce7f8 | 2263 | up_read(&tty->termios_rwsem); |
9356b535 | 2264 | |
37da7bbb LT |
2265 | timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, |
2266 | timeout); | |
9356b535 | 2267 | |
52bce7f8 PH |
2268 | down_read(&tty->termios_rwsem); |
2269 | continue; | |
1da177e4 LT |
2270 | } |
2271 | ||
53c5ee2c | 2272 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2273 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
ac8f3bf8 | 2274 | if (retval) |
1da177e4 LT |
2275 | break; |
2276 | } else { | |
2277 | int uncopied; | |
95ea90db PH |
2278 | |
2279 | /* Deal with packet mode. */ | |
2280 | if (packet && b == buf) { | |
2281 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { | |
2282 | retval = -EFAULT; | |
2283 | b--; | |
2284 | break; | |
2285 | } | |
2286 | nr--; | |
2287 | } | |
2288 | ||
1da177e4 LT |
2289 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2290 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2291 | if (uncopied) { | |
2292 | retval = -EFAULT; | |
2293 | break; | |
2294 | } | |
2295 | } | |
2296 | ||
6367ca72 | 2297 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2298 | |
2299 | if (b - buf >= minimum) | |
2300 | break; | |
2301 | if (time) | |
2302 | timeout = time; | |
2303 | } | |
2c5dc464 PH |
2304 | if (tail != ldata->read_tail) |
2305 | n_tty_kick_worker(tty); | |
42458f41 PH |
2306 | up_read(&tty->termios_rwsem); |
2307 | ||
1da177e4 | 2308 | remove_wait_queue(&tty->read_wait, &wait); |
1da177e4 | 2309 | if (!waitqueue_active(&tty->read_wait)) |
f6c8dbe6 | 2310 | ldata->minimum_to_wake = minimum; |
1da177e4 | 2311 | |
aebf0453 PH |
2312 | mutex_unlock(&ldata->atomic_read_lock); |
2313 | ||
40d5e090 PH |
2314 | if (b - buf) |
2315 | retval = b - buf; | |
1da177e4 LT |
2316 | |
2317 | return retval; | |
2318 | } | |
2319 | ||
2320 | /** | |
11a96d18 | 2321 | * n_tty_write - write function for tty |
1da177e4 LT |
2322 | * @tty: tty device |
2323 | * @file: file object | |
2324 | * @buf: userspace buffer pointer | |
2325 | * @nr: size of I/O | |
2326 | * | |
a88a69c9 | 2327 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2328 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2329 | * and other such events. Since the receive code will echo characters, |
2330 | * thus calling driver write methods, the output_lock is used in | |
2331 | * the output processing functions called here as well as in the | |
2332 | * echo processing function to protect the column state and space | |
2333 | * left in the buffer. | |
1da177e4 LT |
2334 | * |
2335 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2336 | * |
2337 | * Locking: output_lock to protect column state and space left | |
2338 | * (note that the process_output*() functions take this | |
2339 | * lock themselves) | |
1da177e4 | 2340 | */ |
4edf1827 | 2341 | |
11a96d18 | 2342 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2343 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2344 | { |
2345 | const unsigned char *b = buf; | |
97d9e28d | 2346 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2347 | int c; |
2348 | ssize_t retval = 0; | |
2349 | ||
2350 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2351 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2352 | retval = tty_check_change(tty); | |
2353 | if (retval) | |
2354 | return retval; | |
2355 | } | |
2356 | ||
9356b535 PH |
2357 | down_read(&tty->termios_rwsem); |
2358 | ||
a88a69c9 JP |
2359 | /* Write out any echoed characters that are still pending */ |
2360 | process_echoes(tty); | |
300a6204 | 2361 | |
1da177e4 LT |
2362 | add_wait_queue(&tty->write_wait, &wait); |
2363 | while (1) { | |
1da177e4 LT |
2364 | if (signal_pending(current)) { |
2365 | retval = -ERESTARTSYS; | |
2366 | break; | |
2367 | } | |
2368 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2369 | retval = -EIO; | |
2370 | break; | |
2371 | } | |
582f5590 | 2372 | if (O_OPOST(tty)) { |
1da177e4 | 2373 | while (nr > 0) { |
a88a69c9 | 2374 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2375 | if (num < 0) { |
2376 | if (num == -EAGAIN) | |
2377 | break; | |
2378 | retval = num; | |
2379 | goto break_out; | |
2380 | } | |
2381 | b += num; | |
2382 | nr -= num; | |
2383 | if (nr == 0) | |
2384 | break; | |
2385 | c = *b; | |
a88a69c9 | 2386 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2387 | break; |
2388 | b++; nr--; | |
2389 | } | |
f34d7a5b AC |
2390 | if (tty->ops->flush_chars) |
2391 | tty->ops->flush_chars(tty); | |
1da177e4 | 2392 | } else { |
4291086b PH |
2393 | struct n_tty_data *ldata = tty->disc_data; |
2394 | ||
d6afe27b | 2395 | while (nr > 0) { |
4291086b | 2396 | mutex_lock(&ldata->output_lock); |
f34d7a5b | 2397 | c = tty->ops->write(tty, b, nr); |
4291086b | 2398 | mutex_unlock(&ldata->output_lock); |
d6afe27b RZ |
2399 | if (c < 0) { |
2400 | retval = c; | |
2401 | goto break_out; | |
2402 | } | |
2403 | if (!c) | |
2404 | break; | |
2405 | b += c; | |
2406 | nr -= c; | |
1da177e4 | 2407 | } |
1da177e4 LT |
2408 | } |
2409 | if (!nr) | |
2410 | break; | |
2411 | if (file->f_flags & O_NONBLOCK) { | |
2412 | retval = -EAGAIN; | |
2413 | break; | |
2414 | } | |
9356b535 PH |
2415 | up_read(&tty->termios_rwsem); |
2416 | ||
97d9e28d | 2417 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
9356b535 PH |
2418 | |
2419 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2420 | } |
2421 | break_out: | |
1da177e4 | 2422 | remove_wait_queue(&tty->write_wait, &wait); |
ff8cb0fd TP |
2423 | if (b - buf != nr && tty->fasync) |
2424 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2425 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2426 | return (b - buf) ? b - buf : retval; |
2427 | } | |
2428 | ||
2429 | /** | |
11a96d18 | 2430 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2431 | * @tty: terminal device |
2432 | * @file: file accessing it | |
2433 | * @wait: poll table | |
2434 | * | |
2435 | * Called when the line discipline is asked to poll() for data or | |
2436 | * for special events. This code is not serialized with respect to | |
2437 | * other events save open/close. | |
2438 | * | |
2439 | * This code must be sure never to sleep through a hangup. | |
2440 | * Called without the kernel lock held - fine | |
1da177e4 | 2441 | */ |
4edf1827 | 2442 | |
11a96d18 | 2443 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2444 | poll_table *wait) |
1da177e4 | 2445 | { |
f6c8dbe6 | 2446 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2447 | unsigned int mask = 0; |
2448 | ||
2449 | poll_wait(file, &tty->read_wait, wait); | |
2450 | poll_wait(file, &tty->write_wait, wait); | |
1a48632f PH |
2451 | if (check_other_done(tty)) |
2452 | mask |= POLLHUP; | |
eafbe67f | 2453 | if (input_available_p(tty, 1)) |
1da177e4 LT |
2454 | mask |= POLLIN | POLLRDNORM; |
2455 | if (tty->packet && tty->link->ctrl_status) | |
2456 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
1da177e4 LT |
2457 | if (tty_hung_up_p(file)) |
2458 | mask |= POLLHUP; | |
2459 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2460 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2461 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2462 | else |
f6c8dbe6 | 2463 | ldata->minimum_to_wake = 1; |
1da177e4 | 2464 | } |
f34d7a5b AC |
2465 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2466 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2467 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2468 | mask |= POLLOUT | POLLWRNORM; |
2469 | return mask; | |
2470 | } | |
2471 | ||
57c94121 | 2472 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2473 | { |
bc5a5e3f | 2474 | size_t nr, head, tail; |
47afa7a5 | 2475 | |
a73d3d69 | 2476 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2477 | return 0; |
ba2e68ac JS |
2478 | head = ldata->canon_head; |
2479 | tail = ldata->read_tail; | |
bc5a5e3f | 2480 | nr = head - tail; |
47afa7a5 AC |
2481 | /* Skip EOF-chars.. */ |
2482 | while (head != tail) { | |
bc5a5e3f PH |
2483 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2484 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2485 | nr--; |
bc5a5e3f | 2486 | tail++; |
47afa7a5 AC |
2487 | } |
2488 | return nr; | |
2489 | } | |
2490 | ||
2491 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2492 | unsigned int cmd, unsigned long arg) | |
2493 | { | |
ba2e68ac | 2494 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2495 | int retval; |
2496 | ||
2497 | switch (cmd) { | |
2498 | case TIOCOUTQ: | |
2499 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2500 | case TIOCINQ: | |
6d76bd26 | 2501 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2502 | if (L_ICANON(tty)) |
57c94121 | 2503 | retval = inq_canon(ldata); |
6d76bd26 PH |
2504 | else |
2505 | retval = read_cnt(ldata); | |
2506 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2507 | return put_user(retval, (unsigned int __user *) arg); |
2508 | default: | |
2509 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2510 | } | |
2511 | } | |
2512 | ||
f6c8dbe6 PH |
2513 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2514 | { | |
2515 | struct n_tty_data *ldata = tty->disc_data; | |
2516 | ||
2517 | if (!waitqueue_active(&tty->read_wait)) { | |
2518 | if (on) | |
2519 | ldata->minimum_to_wake = 1; | |
2520 | else if (!tty->fasync) | |
2521 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2522 | } | |
2523 | } | |
2524 | ||
a352def2 | 2525 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2526 | .magic = TTY_LDISC_MAGIC, |
2527 | .name = "n_tty", | |
2528 | .open = n_tty_open, | |
2529 | .close = n_tty_close, | |
2530 | .flush_buffer = n_tty_flush_buffer, | |
2531 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2532 | .read = n_tty_read, |
2533 | .write = n_tty_write, | |
e10cc1df PF |
2534 | .ioctl = n_tty_ioctl, |
2535 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2536 | .poll = n_tty_poll, |
e10cc1df | 2537 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2538 | .write_wakeup = n_tty_write_wakeup, |
2539 | .fasync = n_tty_fasync, | |
24a89d1c | 2540 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2541 | }; |
572b9adb RG |
2542 | |
2543 | /** | |
2544 | * n_tty_inherit_ops - inherit N_TTY methods | |
2545 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2546 | * | |
593fb1ae | 2547 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2548 | * methods. |
2549 | */ | |
2550 | ||
2551 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2552 | { | |
2553 | *ops = tty_ldisc_N_TTY; | |
2554 | ops->owner = NULL; | |
2555 | ops->refcount = ops->flags = 0; | |
2556 | } | |
2557 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |