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 | ||
72586c60 LA |
165 | static inline int tty_copy_to_user(struct tty_struct *tty, |
166 | void __user *to, | |
167 | const void *from, | |
168 | unsigned long n) | |
169 | { | |
170 | struct n_tty_data *ldata = tty->disc_data; | |
171 | ||
172 | tty_audit_add_data(tty, to, n, ldata->icanon); | |
173 | return copy_to_user(to, from, n); | |
174 | } | |
175 | ||
24a89d1c | 176 | /** |
2c5dc464 | 177 | * n_tty_kick_worker - start input worker (if required) |
24a89d1c PH |
178 | * @tty: terminal |
179 | * | |
2c5dc464 | 180 | * Re-schedules the flip buffer work if it may have stopped |
24a89d1c | 181 | * |
6d76bd26 PH |
182 | * Caller holds exclusive termios_rwsem |
183 | * or | |
184 | * n_tty_read()/consumer path: | |
185 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
186 | */ |
187 | ||
2c5dc464 | 188 | static void n_tty_kick_worker(struct tty_struct *tty) |
7879a9f9 | 189 | { |
24a89d1c PH |
190 | struct n_tty_data *ldata = tty->disc_data; |
191 | ||
2c5dc464 PH |
192 | /* Did the input worker stop? Restart it */ |
193 | if (unlikely(ldata->no_room)) { | |
24a89d1c PH |
194 | ldata->no_room = 0; |
195 | ||
ecbbfd44 | 196 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 197 | "scheduling with invalid itty\n"); |
21622939 PH |
198 | /* see if ldisc has been killed - if so, this means that |
199 | * even though the ldisc has been halted and ->buf.work | |
200 | * cancelled, ->buf.work is about to be rescheduled | |
201 | */ | |
202 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
203 | "scheduling buffer work for halted ldisc\n"); | |
f0f947c1 | 204 | queue_work(system_unbound_wq, &tty->port->buf.work); |
ecbbfd44 | 205 | } |
55db4c64 LT |
206 | } |
207 | ||
9a4aec2d PH |
208 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
209 | { | |
210 | struct n_tty_data *ldata = tty->disc_data; | |
211 | ssize_t n = 0; | |
212 | ||
213 | if (!ldata->icanon) | |
70aca71f | 214 | n = ldata->commit_head - ldata->read_tail; |
9a4aec2d PH |
215 | else |
216 | n = ldata->canon_head - ldata->read_tail; | |
217 | return n; | |
218 | } | |
219 | ||
ee0bab83 PH |
220 | /** |
221 | * n_tty_write_wakeup - asynchronous I/O notifier | |
222 | * @tty: tty device | |
223 | * | |
224 | * Required for the ptys, serial driver etc. since processes | |
225 | * that attach themselves to the master and rely on ASYNC | |
226 | * IO must be woken up | |
227 | */ | |
228 | ||
229 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
230 | { | |
231 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) | |
232 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
233 | } | |
234 | ||
4a23a4df | 235 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 236 | { |
a342846f PH |
237 | struct n_tty_data *ldata = tty->disc_data; |
238 | ||
6367ca72 PH |
239 | /* |
240 | * Check the remaining room for the input canonicalization | |
241 | * mode. We don't want to throttle the driver if we're in | |
242 | * canonical mode and don't have a newline yet! | |
243 | */ | |
a342846f PH |
244 | if (ldata->icanon && ldata->canon_head == ldata->read_tail) |
245 | return; | |
246 | ||
6367ca72 PH |
247 | while (1) { |
248 | int throttled; | |
249 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
5e28cca1 | 250 | if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE) |
6367ca72 PH |
251 | break; |
252 | throttled = tty_throttle_safe(tty); | |
253 | if (!throttled) | |
254 | break; | |
255 | } | |
256 | __tty_set_flow_change(tty, 0); | |
257 | } | |
258 | ||
4b293492 | 259 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 260 | { |
3afb1b39 PH |
261 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
262 | tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { | |
263 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
264 | return; | |
265 | if (!tty->count) | |
266 | return; | |
2c5dc464 | 267 | n_tty_kick_worker(tty); |
3afb1b39 | 268 | n_tty_write_wakeup(tty->link); |
6c67716d PH |
269 | if (waitqueue_active(&tty->link->write_wait)) |
270 | wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); | |
3afb1b39 PH |
271 | return; |
272 | } | |
273 | ||
6367ca72 PH |
274 | /* If there is enough space in the read buffer now, let the |
275 | * low-level driver know. We use chars_in_buffer() to | |
276 | * check the buffer, as it now knows about canonical mode. | |
277 | * Otherwise, if the driver is throttled and the line is | |
278 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
279 | * we won't get any more characters. | |
280 | */ | |
281 | ||
282 | while (1) { | |
283 | int unthrottled; | |
284 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
285 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
286 | break; | |
287 | if (!tty->count) | |
288 | break; | |
2c5dc464 | 289 | n_tty_kick_worker(tty); |
6367ca72 PH |
290 | unthrottled = tty_unthrottle_safe(tty); |
291 | if (!unthrottled) | |
292 | break; | |
293 | } | |
294 | __tty_set_flow_change(tty, 0); | |
295 | } | |
296 | ||
17b82060 AC |
297 | /** |
298 | * put_tty_queue - add character to tty | |
299 | * @c: character | |
57c94121 | 300 | * @ldata: n_tty data |
17b82060 | 301 | * |
6d76bd26 PH |
302 | * Add a character to the tty read_buf queue. |
303 | * | |
304 | * n_tty_receive_buf()/producer path: | |
305 | * caller holds non-exclusive termios_rwsem | |
17b82060 AC |
306 | */ |
307 | ||
19e2ad6a | 308 | static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 309 | { |
8bfbe2de CR |
310 | *read_buf_addr(ldata, ldata->read_head) = c; |
311 | ldata->read_head++; | |
1da177e4 LT |
312 | } |
313 | ||
1da177e4 LT |
314 | /** |
315 | * reset_buffer_flags - reset buffer state | |
316 | * @tty: terminal to reset | |
317 | * | |
25518c68 PH |
318 | * Reset the read buffer counters and clear the flags. |
319 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 320 | * |
6d76bd26 PH |
321 | * Locking: caller holds exclusive termios_rwsem |
322 | * (or locking is not required) | |
1da177e4 | 323 | */ |
a88a69c9 | 324 | |
b66f4fa5 | 325 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 326 | { |
a73d3d69 | 327 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 328 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
70aca71f | 329 | ldata->commit_head = 0; |
1075a6e2 | 330 | ldata->echo_mark = 0; |
40d5e090 | 331 | ldata->line_start = 0; |
a88a69c9 | 332 | |
a73d3d69 | 333 | ldata->erasing = 0; |
3fe780b3 | 334 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 | 335 | ldata->push = 0; |
1da177e4 LT |
336 | } |
337 | ||
a30737ab PH |
338 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
339 | { | |
340 | unsigned long flags; | |
341 | ||
a30737ab | 342 | if (tty->link->packet) { |
54e8e5fc | 343 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
a30737ab | 344 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; |
54e8e5fc | 345 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
6c67716d PH |
346 | if (waitqueue_active(&tty->link->read_wait)) |
347 | wake_up_interruptible(&tty->link->read_wait); | |
a30737ab | 348 | } |
a30737ab PH |
349 | } |
350 | ||
1da177e4 LT |
351 | /** |
352 | * n_tty_flush_buffer - clean input queue | |
353 | * @tty: terminal device | |
354 | * | |
25518c68 PH |
355 | * Flush the input buffer. Called when the tty layer wants the |
356 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
357 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 358 | * |
6d76bd26 PH |
359 | * Holds termios_rwsem to exclude producer/consumer while |
360 | * buffer indices are reset. | |
361 | * | |
362 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 363 | */ |
4edf1827 AC |
364 | |
365 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 366 | { |
6d76bd26 | 367 | down_write(&tty->termios_rwsem); |
b66f4fa5 | 368 | reset_buffer_flags(tty->disc_data); |
2c5dc464 | 369 | n_tty_kick_worker(tty); |
4edf1827 | 370 | |
a30737ab PH |
371 | if (tty->link) |
372 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 373 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
374 | } |
375 | ||
6d76bd26 PH |
376 | /** |
377 | * n_tty_chars_in_buffer - report available bytes | |
378 | * @tty: tty device | |
379 | * | |
380 | * Report the number of characters buffered to be delivered to user | |
381 | * at this instant in time. | |
382 | * | |
383 | * Locking: exclusive termios_rwsem | |
384 | */ | |
385 | ||
a19d0c6a PH |
386 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
387 | { | |
6d76bd26 PH |
388 | ssize_t n; |
389 | ||
47534084 | 390 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
6d76bd26 PH |
391 | |
392 | down_write(&tty->termios_rwsem); | |
393 | n = chars_in_buffer(tty); | |
394 | up_write(&tty->termios_rwsem); | |
395 | return n; | |
a19d0c6a PH |
396 | } |
397 | ||
1da177e4 LT |
398 | /** |
399 | * is_utf8_continuation - utf8 multibyte check | |
400 | * @c: byte to check | |
401 | * | |
402 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
403 | * character. We use this to correctly compute the on screen size | |
404 | * of the character when printing | |
405 | */ | |
4edf1827 | 406 | |
1da177e4 LT |
407 | static inline int is_utf8_continuation(unsigned char c) |
408 | { | |
409 | return (c & 0xc0) == 0x80; | |
410 | } | |
411 | ||
412 | /** | |
413 | * is_continuation - multibyte check | |
414 | * @c: byte to check | |
415 | * | |
416 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
417 | * character and the terminal is in unicode mode. | |
418 | */ | |
4edf1827 | 419 | |
1da177e4 LT |
420 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
421 | { | |
422 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
423 | } | |
424 | ||
425 | /** | |
a88a69c9 | 426 | * do_output_char - output one character |
1da177e4 LT |
427 | * @c: character (or partial unicode symbol) |
428 | * @tty: terminal device | |
a88a69c9 | 429 | * @space: space available in tty driver write buffer |
1da177e4 | 430 | * |
a88a69c9 JP |
431 | * This is a helper function that handles one output character |
432 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
433 | * doing OPOST processing and putting the results in the |
434 | * tty driver's write buffer. | |
a88a69c9 JP |
435 | * |
436 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
437 | * and NLDLY. They simply aren't relevant in the world today. | |
438 | * If you ever need them, add them here. | |
1da177e4 | 439 | * |
a88a69c9 JP |
440 | * Returns the number of bytes of buffer space used or -1 if |
441 | * no space left. | |
442 | * | |
443 | * Locking: should be called under the output_lock to protect | |
444 | * the column state and space left in the buffer | |
1da177e4 | 445 | */ |
4edf1827 | 446 | |
a88a69c9 | 447 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 448 | { |
53c5ee2c | 449 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 450 | int spaces; |
1da177e4 | 451 | |
1da177e4 LT |
452 | if (!space) |
453 | return -1; | |
300a6204 | 454 | |
a88a69c9 JP |
455 | switch (c) { |
456 | case '\n': | |
457 | if (O_ONLRET(tty)) | |
53c5ee2c | 458 | ldata->column = 0; |
a88a69c9 JP |
459 | if (O_ONLCR(tty)) { |
460 | if (space < 2) | |
461 | return -1; | |
ba2e68ac | 462 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 463 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
464 | return 2; |
465 | } | |
ba2e68ac | 466 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
467 | break; |
468 | case '\r': | |
53c5ee2c | 469 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
470 | return 0; |
471 | if (O_OCRNL(tty)) { | |
472 | c = '\n'; | |
473 | if (O_ONLRET(tty)) | |
ba2e68ac | 474 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 475 | break; |
a88a69c9 | 476 | } |
ba2e68ac | 477 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
478 | break; |
479 | case '\t': | |
53c5ee2c | 480 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
481 | if (O_TABDLY(tty) == XTABS) { |
482 | if (space < spaces) | |
483 | return -1; | |
53c5ee2c | 484 | ldata->column += spaces; |
a88a69c9 JP |
485 | tty->ops->write(tty, " ", spaces); |
486 | return spaces; | |
1da177e4 | 487 | } |
53c5ee2c | 488 | ldata->column += spaces; |
a88a69c9 JP |
489 | break; |
490 | case '\b': | |
53c5ee2c JS |
491 | if (ldata->column > 0) |
492 | ldata->column--; | |
a88a69c9 JP |
493 | break; |
494 | default: | |
a59c0d6f JP |
495 | if (!iscntrl(c)) { |
496 | if (O_OLCUC(tty)) | |
497 | c = toupper(c); | |
498 | if (!is_continuation(c, tty)) | |
53c5ee2c | 499 | ldata->column++; |
a59c0d6f | 500 | } |
a88a69c9 | 501 | break; |
1da177e4 | 502 | } |
a88a69c9 | 503 | |
f34d7a5b | 504 | tty_put_char(tty, c); |
a88a69c9 JP |
505 | return 1; |
506 | } | |
507 | ||
508 | /** | |
509 | * process_output - output post processor | |
510 | * @c: character (or partial unicode symbol) | |
511 | * @tty: terminal device | |
512 | * | |
ee5aa7b8 JP |
513 | * Output one character with OPOST processing. |
514 | * Returns -1 when the output device is full and the character | |
515 | * must be retried. | |
a88a69c9 JP |
516 | * |
517 | * Locking: output_lock to protect column state and space left | |
518 | * (also, this is called from n_tty_write under the | |
519 | * tty layer write lock) | |
520 | */ | |
521 | ||
522 | static int process_output(unsigned char c, struct tty_struct *tty) | |
523 | { | |
bddc7152 | 524 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
525 | int space, retval; |
526 | ||
bddc7152 | 527 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
528 | |
529 | space = tty_write_room(tty); | |
530 | retval = do_output_char(c, tty, space); | |
531 | ||
bddc7152 | 532 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
533 | if (retval < 0) |
534 | return -1; | |
535 | else | |
536 | return 0; | |
1da177e4 LT |
537 | } |
538 | ||
539 | /** | |
a88a69c9 | 540 | * process_output_block - block post processor |
1da177e4 | 541 | * @tty: terminal device |
ee5aa7b8 JP |
542 | * @buf: character buffer |
543 | * @nr: number of bytes to output | |
544 | * | |
545 | * Output a block of characters with OPOST processing. | |
546 | * Returns the number of characters output. | |
1da177e4 LT |
547 | * |
548 | * This path is used to speed up block console writes, among other | |
549 | * things when processing blocks of output data. It handles only | |
550 | * the simple cases normally found and helps to generate blocks of | |
551 | * symbols for the console driver and thus improve performance. | |
552 | * | |
a88a69c9 JP |
553 | * Locking: output_lock to protect column state and space left |
554 | * (also, this is called from n_tty_write under the | |
555 | * tty layer write lock) | |
1da177e4 | 556 | */ |
4edf1827 | 557 | |
a88a69c9 JP |
558 | static ssize_t process_output_block(struct tty_struct *tty, |
559 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 560 | { |
53c5ee2c | 561 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 562 | int space; |
bbd20759 | 563 | int i; |
1da177e4 LT |
564 | const unsigned char *cp; |
565 | ||
bddc7152 | 566 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 567 | |
f34d7a5b | 568 | space = tty_write_room(tty); |
300a6204 | 569 | if (!space) { |
bddc7152 | 570 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 571 | return 0; |
a88a69c9 | 572 | } |
1da177e4 LT |
573 | if (nr > space) |
574 | nr = space; | |
575 | ||
576 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
577 | unsigned char c = *cp; |
578 | ||
579 | switch (c) { | |
1da177e4 LT |
580 | case '\n': |
581 | if (O_ONLRET(tty)) | |
53c5ee2c | 582 | ldata->column = 0; |
1da177e4 LT |
583 | if (O_ONLCR(tty)) |
584 | goto break_out; | |
ba2e68ac | 585 | ldata->canon_column = ldata->column; |
1da177e4 LT |
586 | break; |
587 | case '\r': | |
53c5ee2c | 588 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
589 | goto break_out; |
590 | if (O_OCRNL(tty)) | |
591 | goto break_out; | |
ba2e68ac | 592 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
593 | break; |
594 | case '\t': | |
595 | goto break_out; | |
596 | case '\b': | |
53c5ee2c JS |
597 | if (ldata->column > 0) |
598 | ldata->column--; | |
1da177e4 LT |
599 | break; |
600 | default: | |
a59c0d6f JP |
601 | if (!iscntrl(c)) { |
602 | if (O_OLCUC(tty)) | |
603 | goto break_out; | |
604 | if (!is_continuation(c, tty)) | |
53c5ee2c | 605 | ldata->column++; |
a59c0d6f | 606 | } |
1da177e4 LT |
607 | break; |
608 | } | |
609 | } | |
610 | break_out: | |
f34d7a5b | 611 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 612 | |
bddc7152 | 613 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
614 | return i; |
615 | } | |
616 | ||
a88a69c9 JP |
617 | /** |
618 | * process_echoes - write pending echo characters | |
619 | * @tty: terminal device | |
620 | * | |
621 | * Write previously buffered echo (and other ldisc-generated) | |
622 | * characters to the tty. | |
623 | * | |
624 | * Characters generated by the ldisc (including echoes) need to | |
625 | * be buffered because the driver's write buffer can fill during | |
626 | * heavy program output. Echoing straight to the driver will | |
627 | * often fail under these conditions, causing lost characters and | |
628 | * resulting mismatches of ldisc state information. | |
629 | * | |
630 | * Since the ldisc state must represent the characters actually sent | |
631 | * to the driver at the time of the write, operations like certain | |
632 | * changes in column state are also saved in the buffer and executed | |
633 | * here. | |
634 | * | |
635 | * A circular fifo buffer is used so that the most recent characters | |
636 | * are prioritized. Also, when control characters are echoed with a | |
637 | * prefixed "^", the pair is treated atomically and thus not separated. | |
638 | * | |
019ebdf9 | 639 | * Locking: callers must hold output_lock |
a88a69c9 JP |
640 | */ |
641 | ||
bc5b1ec5 | 642 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 643 | { |
53c5ee2c | 644 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 645 | int space, old_space; |
addaebcc | 646 | size_t tail; |
a88a69c9 | 647 | unsigned char c; |
a88a69c9 | 648 | |
bc5b1ec5 | 649 | old_space = space = tty_write_room(tty); |
a88a69c9 | 650 | |
addaebcc | 651 | tail = ldata->echo_tail; |
29c7c5ca | 652 | while (ldata->echo_commit != tail) { |
addaebcc | 653 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
654 | if (c == ECHO_OP_START) { |
655 | unsigned char op; | |
a88a69c9 JP |
656 | int no_space_left = 0; |
657 | ||
658 | /* | |
659 | * If the buffer byte is the start of a multi-byte | |
660 | * operation, get the next byte, which is either the | |
661 | * op code or a control character value. | |
662 | */ | |
addaebcc | 663 | op = echo_buf(ldata, tail + 1); |
300a6204 | 664 | |
a88a69c9 JP |
665 | switch (op) { |
666 | unsigned int num_chars, num_bs; | |
667 | ||
668 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 669 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
670 | |
671 | /* | |
672 | * Determine how many columns to go back | |
673 | * in order to erase the tab. | |
674 | * This depends on the number of columns | |
675 | * used by other characters within the tab | |
676 | * area. If this (modulo 8) count is from | |
677 | * the start of input rather than from a | |
678 | * previous tab, we offset by canon column. | |
679 | * Otherwise, tab spacing is normal. | |
680 | */ | |
681 | if (!(num_chars & 0x80)) | |
ba2e68ac | 682 | num_chars += ldata->canon_column; |
a88a69c9 JP |
683 | num_bs = 8 - (num_chars & 7); |
684 | ||
685 | if (num_bs > space) { | |
686 | no_space_left = 1; | |
687 | break; | |
688 | } | |
689 | space -= num_bs; | |
690 | while (num_bs--) { | |
691 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
692 | if (ldata->column > 0) |
693 | ldata->column--; | |
a88a69c9 | 694 | } |
addaebcc | 695 | tail += 3; |
a88a69c9 JP |
696 | break; |
697 | ||
698 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 699 | ldata->canon_column = ldata->column; |
addaebcc | 700 | tail += 2; |
a88a69c9 JP |
701 | break; |
702 | ||
703 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
704 | if (ldata->column > 0) |
705 | ldata->column--; | |
addaebcc | 706 | tail += 2; |
a88a69c9 JP |
707 | break; |
708 | ||
709 | case ECHO_OP_START: | |
710 | /* This is an escaped echo op start code */ | |
711 | if (!space) { | |
712 | no_space_left = 1; | |
713 | break; | |
714 | } | |
715 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 716 | ldata->column++; |
a88a69c9 | 717 | space--; |
addaebcc | 718 | tail += 2; |
a88a69c9 JP |
719 | break; |
720 | ||
721 | default: | |
a88a69c9 | 722 | /* |
62b26358 JP |
723 | * If the op is not a special byte code, |
724 | * it is a ctrl char tagged to be echoed | |
725 | * as "^X" (where X is the letter | |
726 | * representing the control char). | |
727 | * Note that we must ensure there is | |
728 | * enough space for the whole ctrl pair. | |
729 | * | |
a88a69c9 | 730 | */ |
62b26358 JP |
731 | if (space < 2) { |
732 | no_space_left = 1; | |
733 | break; | |
734 | } | |
735 | tty_put_char(tty, '^'); | |
736 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 737 | ldata->column += 2; |
62b26358 | 738 | space -= 2; |
addaebcc | 739 | tail += 2; |
a88a69c9 JP |
740 | } |
741 | ||
742 | if (no_space_left) | |
743 | break; | |
744 | } else { | |
582f5590 | 745 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
746 | int retval = do_output_char(c, tty, space); |
747 | if (retval < 0) | |
748 | break; | |
749 | space -= retval; | |
750 | } else { | |
751 | if (!space) | |
752 | break; | |
753 | tty_put_char(tty, c); | |
754 | space -= 1; | |
755 | } | |
addaebcc | 756 | tail += 1; |
a88a69c9 | 757 | } |
a88a69c9 JP |
758 | } |
759 | ||
cbfd0340 PH |
760 | /* If the echo buffer is nearly full (so that the possibility exists |
761 | * of echo overrun before the next commit), then discard enough | |
762 | * data at the tail to prevent a subsequent overrun */ | |
763 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 764 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 765 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
766 | tail += 3; |
767 | else | |
768 | tail += 2; | |
769 | } else | |
770 | tail++; | |
771 | } | |
772 | ||
addaebcc | 773 | ldata->echo_tail = tail; |
bc5b1ec5 | 774 | return old_space - space; |
019ebdf9 PH |
775 | } |
776 | ||
777 | static void commit_echoes(struct tty_struct *tty) | |
778 | { | |
779 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 780 | size_t nr, old, echoed; |
cbfd0340 PH |
781 | size_t head; |
782 | ||
783 | head = ldata->echo_head; | |
1075a6e2 | 784 | ldata->echo_mark = head; |
cbfd0340 PH |
785 | old = ldata->echo_commit - ldata->echo_tail; |
786 | ||
787 | /* Process committed echoes if the accumulated # of bytes | |
788 | * is over the threshold (and try again each time another | |
789 | * block is accumulated) */ | |
790 | nr = head - ldata->echo_tail; | |
791 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
792 | return; | |
a88a69c9 | 793 | |
019ebdf9 | 794 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 795 | ldata->echo_commit = head; |
bc5b1ec5 | 796 | echoed = __process_echoes(tty); |
bddc7152 | 797 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 798 | |
bc5b1ec5 | 799 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
800 | tty->ops->flush_chars(tty); |
801 | } | |
802 | ||
019ebdf9 | 803 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
804 | { |
805 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 806 | size_t echoed; |
17bd7907 | 807 | |
e2613be5 | 808 | if (ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
809 | return; |
810 | ||
811 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 812 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 813 | echoed = __process_echoes(tty); |
019ebdf9 PH |
814 | mutex_unlock(&ldata->output_lock); |
815 | ||
bc5b1ec5 | 816 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 817 | tty->ops->flush_chars(tty); |
17bd7907 PH |
818 | } |
819 | ||
1075a6e2 | 820 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
821 | static void flush_echoes(struct tty_struct *tty) |
822 | { | |
823 | struct n_tty_data *ldata = tty->disc_data; | |
824 | ||
39434abd PH |
825 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
826 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
827 | return; |
828 | ||
829 | mutex_lock(&ldata->output_lock); | |
830 | ldata->echo_commit = ldata->echo_head; | |
831 | __process_echoes(tty); | |
832 | mutex_unlock(&ldata->output_lock); | |
833 | } | |
834 | ||
a88a69c9 JP |
835 | /** |
836 | * add_echo_byte - add a byte to the echo buffer | |
837 | * @c: unicode byte to echo | |
57c94121 | 838 | * @ldata: n_tty data |
a88a69c9 JP |
839 | * |
840 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
841 | */ |
842 | ||
cbfd0340 | 843 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 844 | { |
addaebcc | 845 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
846 | } |
847 | ||
848 | /** | |
849 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 850 | * @ldata: n_tty data |
a88a69c9 JP |
851 | * |
852 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
853 | */ |
854 | ||
57c94121 | 855 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 856 | { |
57c94121 JS |
857 | add_echo_byte(ECHO_OP_START, ldata); |
858 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
859 | } |
860 | ||
861 | /** | |
862 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 863 | * @ldata: n_tty data |
a88a69c9 JP |
864 | * |
865 | * Add an operation to the echo buffer to set the canon column | |
866 | * to the current column. | |
a88a69c9 JP |
867 | */ |
868 | ||
57c94121 | 869 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 870 | { |
57c94121 JS |
871 | add_echo_byte(ECHO_OP_START, ldata); |
872 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
873 | } |
874 | ||
875 | /** | |
876 | * echo_erase_tab - add operation to erase a tab | |
877 | * @num_chars: number of character columns already used | |
878 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 879 | * @ldata: n_tty data |
a88a69c9 JP |
880 | * |
881 | * Add an operation to the echo buffer to erase a tab. | |
882 | * | |
883 | * Called by the eraser function, which knows how many character | |
884 | * columns have been used since either a previous tab or the start | |
885 | * of input. This information will be used later, along with | |
886 | * canon column (if applicable), to go back the correct number | |
887 | * of columns. | |
a88a69c9 JP |
888 | */ |
889 | ||
890 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 891 | struct n_tty_data *ldata) |
a88a69c9 | 892 | { |
57c94121 JS |
893 | add_echo_byte(ECHO_OP_START, ldata); |
894 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
895 | |
896 | /* We only need to know this modulo 8 (tab spacing) */ | |
897 | num_chars &= 7; | |
898 | ||
899 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
900 | if (after_tab) | |
901 | num_chars |= 0x80; | |
300a6204 | 902 | |
57c94121 | 903 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
904 | } |
905 | ||
906 | /** | |
907 | * echo_char_raw - echo a character raw | |
908 | * @c: unicode byte to echo | |
909 | * @tty: terminal device | |
910 | * | |
911 | * Echo user input back onto the screen. This must be called only when | |
912 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
913 | * | |
914 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
915 | */ |
916 | ||
57c94121 | 917 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 918 | { |
a88a69c9 | 919 | if (c == ECHO_OP_START) { |
57c94121 JS |
920 | add_echo_byte(ECHO_OP_START, ldata); |
921 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 922 | } else { |
57c94121 | 923 | add_echo_byte(c, ldata); |
a88a69c9 | 924 | } |
a88a69c9 | 925 | } |
1da177e4 | 926 | |
1da177e4 | 927 | /** |
a88a69c9 | 928 | * echo_char - echo a character |
1da177e4 LT |
929 | * @c: unicode byte to echo |
930 | * @tty: terminal device | |
931 | * | |
4edf1827 | 932 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 933 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 934 | * |
62b26358 JP |
935 | * This variant tags control characters to be echoed as "^X" |
936 | * (where X is the letter representing the control char). | |
1da177e4 LT |
937 | */ |
938 | ||
939 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
940 | { | |
bddc7152 JS |
941 | struct n_tty_data *ldata = tty->disc_data; |
942 | ||
a88a69c9 | 943 | if (c == ECHO_OP_START) { |
57c94121 JS |
944 | add_echo_byte(ECHO_OP_START, ldata); |
945 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 946 | } else { |
62b26358 | 947 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
948 | add_echo_byte(ECHO_OP_START, ldata); |
949 | add_echo_byte(c, ldata); | |
a88a69c9 | 950 | } |
1da177e4 LT |
951 | } |
952 | ||
17b82060 | 953 | /** |
a88a69c9 | 954 | * finish_erasing - complete erase |
57c94121 | 955 | * @ldata: n_tty data |
17b82060 | 956 | */ |
a88a69c9 | 957 | |
57c94121 | 958 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 959 | { |
53c5ee2c | 960 | if (ldata->erasing) { |
57c94121 | 961 | echo_char_raw('/', ldata); |
53c5ee2c | 962 | ldata->erasing = 0; |
1da177e4 LT |
963 | } |
964 | } | |
965 | ||
966 | /** | |
967 | * eraser - handle erase function | |
968 | * @c: character input | |
969 | * @tty: terminal device | |
970 | * | |
3a4fa0a2 | 971 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
972 | * present in the stream from the driver layer. Handles the complexities |
973 | * of UTF-8 multibyte symbols. | |
17b82060 | 974 | * |
6d76bd26 PH |
975 | * n_tty_receive_buf()/producer path: |
976 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 977 | */ |
4edf1827 | 978 | |
1da177e4 LT |
979 | static void eraser(unsigned char c, struct tty_struct *tty) |
980 | { | |
53c5ee2c | 981 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 982 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
983 | size_t head; |
984 | size_t cnt; | |
985 | int seen_alnums; | |
1da177e4 | 986 | |
ba2e68ac | 987 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 988 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
989 | return; |
990 | } | |
991 | if (c == ERASE_CHAR(tty)) | |
992 | kill_type = ERASE; | |
993 | else if (c == WERASE_CHAR(tty)) | |
994 | kill_type = WERASE; | |
995 | else { | |
996 | if (!L_ECHO(tty)) { | |
ba2e68ac | 997 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
998 | return; |
999 | } | |
1000 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 1001 | ldata->read_head = ldata->canon_head; |
57c94121 | 1002 | finish_erasing(ldata); |
1da177e4 LT |
1003 | echo_char(KILL_CHAR(tty), tty); |
1004 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
1005 | if (L_ECHOK(tty)) | |
57c94121 | 1006 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1007 | return; |
1008 | } | |
1009 | kill_type = KILL; | |
1010 | } | |
1011 | ||
1012 | seen_alnums = 0; | |
ba2e68ac JS |
1013 | while (ldata->read_head != ldata->canon_head) { |
1014 | head = ldata->read_head; | |
1da177e4 LT |
1015 | |
1016 | /* erase a single possibly multibyte character */ | |
1017 | do { | |
bc5a5e3f PH |
1018 | head--; |
1019 | c = read_buf(ldata, head); | |
ba2e68ac | 1020 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1021 | |
1022 | /* do not partially erase */ | |
1023 | if (is_continuation(c, tty)) | |
1024 | break; | |
1025 | ||
1026 | if (kill_type == WERASE) { | |
1027 | /* Equivalent to BSD's ALTWERASE. */ | |
1028 | if (isalnum(c) || c == '_') | |
1029 | seen_alnums++; | |
1030 | else if (seen_alnums) | |
1031 | break; | |
1032 | } | |
bc5a5e3f | 1033 | cnt = ldata->read_head - head; |
ba2e68ac | 1034 | ldata->read_head = head; |
1da177e4 LT |
1035 | if (L_ECHO(tty)) { |
1036 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1037 | if (!ldata->erasing) { |
57c94121 | 1038 | echo_char_raw('\\', ldata); |
53c5ee2c | 1039 | ldata->erasing = 1; |
1da177e4 LT |
1040 | } |
1041 | /* if cnt > 1, output a multi-byte character */ | |
1042 | echo_char(c, tty); | |
1043 | while (--cnt > 0) { | |
bc5a5e3f PH |
1044 | head++; |
1045 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1046 | echo_move_back_col(ldata); |
1da177e4 LT |
1047 | } |
1048 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1049 | echo_char(ERASE_CHAR(tty), tty); | |
1050 | } else if (c == '\t') { | |
a88a69c9 JP |
1051 | unsigned int num_chars = 0; |
1052 | int after_tab = 0; | |
bc5a5e3f | 1053 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1054 | |
1055 | /* | |
1056 | * Count the columns used for characters | |
1057 | * since the start of input or after a | |
1058 | * previous tab. | |
1059 | * This info is used to go back the correct | |
1060 | * number of columns. | |
1061 | */ | |
ba2e68ac | 1062 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1063 | tail--; |
1064 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1065 | if (c == '\t') { |
1066 | after_tab = 1; | |
1067 | break; | |
300a6204 | 1068 | } else if (iscntrl(c)) { |
1da177e4 | 1069 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1070 | num_chars += 2; |
1071 | } else if (!is_continuation(c, tty)) { | |
1072 | num_chars++; | |
1073 | } | |
1da177e4 | 1074 | } |
57c94121 | 1075 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1076 | } else { |
1077 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1078 | echo_char_raw('\b', ldata); |
1079 | echo_char_raw(' ', ldata); | |
1080 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1081 | } |
1082 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1083 | echo_char_raw('\b', ldata); |
1084 | echo_char_raw(' ', ldata); | |
1085 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1086 | } |
1087 | } | |
1088 | } | |
1089 | if (kill_type == ERASE) | |
1090 | break; | |
1091 | } | |
ba2e68ac | 1092 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1093 | finish_erasing(ldata); |
1da177e4 LT |
1094 | } |
1095 | ||
1096 | /** | |
1097 | * isig - handle the ISIG optio | |
1098 | * @sig: signal | |
1099 | * @tty: terminal | |
1da177e4 | 1100 | * |
8c985d18 PH |
1101 | * Called when a signal is being sent due to terminal input. |
1102 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1103 | * |
d2b6f447 PH |
1104 | * Performs input and output flush if !NOFLSH. In this context, the echo |
1105 | * buffer is 'output'. The signal is processed first to alert any current | |
1106 | * readers or writers to discontinue and exit their i/o loops. | |
1107 | * | |
8c985d18 | 1108 | * Locking: ctrl_lock |
1da177e4 | 1109 | */ |
4edf1827 | 1110 | |
4b293492 | 1111 | static void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1112 | { |
d2b6f447 | 1113 | struct n_tty_data *ldata = tty->disc_data; |
8c985d18 PH |
1114 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1115 | if (tty_pgrp) { | |
1116 | kill_pgrp(tty_pgrp, sig, 1); | |
1117 | put_pid(tty_pgrp); | |
1da177e4 | 1118 | } |
d2b6f447 PH |
1119 | |
1120 | if (!L_NOFLSH(tty)) { | |
1121 | up_read(&tty->termios_rwsem); | |
1122 | down_write(&tty->termios_rwsem); | |
1123 | ||
1124 | /* clear echo buffer */ | |
1125 | mutex_lock(&ldata->output_lock); | |
1126 | ldata->echo_head = ldata->echo_tail = 0; | |
1127 | ldata->echo_mark = ldata->echo_commit = 0; | |
1128 | mutex_unlock(&ldata->output_lock); | |
1129 | ||
1130 | /* clear output buffer */ | |
1131 | tty_driver_flush_buffer(tty); | |
1132 | ||
1133 | /* clear input buffer */ | |
1134 | reset_buffer_flags(tty->disc_data); | |
1135 | ||
1136 | /* notify pty master of flush */ | |
1137 | if (tty->link) | |
1138 | n_tty_packet_mode_flush(tty); | |
1139 | ||
1140 | up_write(&tty->termios_rwsem); | |
1141 | down_read(&tty->termios_rwsem); | |
1142 | } | |
1da177e4 LT |
1143 | } |
1144 | ||
1145 | /** | |
1146 | * n_tty_receive_break - handle break | |
1147 | * @tty: terminal | |
1148 | * | |
1149 | * An RS232 break event has been hit in the incoming bitstream. This | |
1150 | * can cause a variety of events depending upon the termios settings. | |
1151 | * | |
6d76bd26 PH |
1152 | * n_tty_receive_buf()/producer path: |
1153 | * caller holds non-exclusive termios_rwsem | |
6d76bd26 PH |
1154 | * |
1155 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1156 | */ |
4edf1827 | 1157 | |
4b293492 | 1158 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1159 | { |
57c94121 JS |
1160 | struct n_tty_data *ldata = tty->disc_data; |
1161 | ||
1da177e4 LT |
1162 | if (I_IGNBRK(tty)) |
1163 | return; | |
1164 | if (I_BRKINT(tty)) { | |
8c985d18 | 1165 | isig(SIGINT, tty); |
1da177e4 LT |
1166 | return; |
1167 | } | |
1168 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1169 | put_tty_queue('\377', ldata); |
1170 | put_tty_queue('\0', ldata); | |
1da177e4 | 1171 | } |
57c94121 | 1172 | put_tty_queue('\0', ldata); |
6c67716d | 1173 | if (waitqueue_active(&tty->read_wait)) |
57087d51 | 1174 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 LT |
1175 | } |
1176 | ||
1177 | /** | |
1178 | * n_tty_receive_overrun - handle overrun reporting | |
1179 | * @tty: terminal | |
1180 | * | |
1181 | * Data arrived faster than we could process it. While the tty | |
1182 | * driver has flagged this the bits that were missed are gone | |
1183 | * forever. | |
1184 | * | |
1185 | * Called from the receive_buf path so single threaded. Does not | |
1186 | * need locking as num_overrun and overrun_time are function | |
1187 | * private. | |
1188 | */ | |
4edf1827 | 1189 | |
4b293492 | 1190 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1191 | { |
53c5ee2c | 1192 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1193 | |
53c5ee2c JS |
1194 | ldata->num_overrun++; |
1195 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1196 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 | 1197 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
429b4749 | 1198 | tty_name(tty), |
53c5ee2c JS |
1199 | ldata->num_overrun); |
1200 | ldata->overrun_time = jiffies; | |
1201 | ldata->num_overrun = 0; | |
1da177e4 LT |
1202 | } |
1203 | } | |
1204 | ||
1205 | /** | |
1206 | * n_tty_receive_parity_error - error notifier | |
1207 | * @tty: terminal device | |
1208 | * @c: character | |
1209 | * | |
1210 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1211 | * the error case if necessary. |
1212 | * | |
1213 | * n_tty_receive_buf()/producer path: | |
1214 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 1215 | */ |
4b293492 | 1216 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1217 | { |
57c94121 JS |
1218 | struct n_tty_data *ldata = tty->disc_data; |
1219 | ||
66528f90 PH |
1220 | if (I_INPCK(tty)) { |
1221 | if (I_IGNPAR(tty)) | |
1222 | return; | |
1223 | if (I_PARMRK(tty)) { | |
1224 | put_tty_queue('\377', ldata); | |
1225 | put_tty_queue('\0', ldata); | |
1226 | put_tty_queue(c, ldata); | |
1227 | } else | |
1228 | put_tty_queue('\0', ldata); | |
1229 | } else | |
57c94121 | 1230 | put_tty_queue(c, ldata); |
6c67716d | 1231 | if (waitqueue_active(&tty->read_wait)) |
57087d51 | 1232 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 LT |
1233 | } |
1234 | ||
b0ac50be PH |
1235 | static void |
1236 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1237 | { | |
d2b6f447 | 1238 | isig(signal, tty); |
b0ac50be PH |
1239 | if (I_IXON(tty)) |
1240 | start_tty(tty); | |
1241 | if (L_ECHO(tty)) { | |
1242 | echo_char(c, tty); | |
1243 | commit_echoes(tty); | |
e2613be5 PH |
1244 | } else |
1245 | process_echoes(tty); | |
b0ac50be PH |
1246 | return; |
1247 | } | |
1248 | ||
1da177e4 LT |
1249 | /** |
1250 | * n_tty_receive_char - perform processing | |
1251 | * @tty: terminal device | |
1252 | * @c: character | |
1253 | * | |
1254 | * Process an individual character of input received from the driver. | |
4edf1827 | 1255 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1256 | * driver above. |
6d76bd26 PH |
1257 | * |
1258 | * n_tty_receive_buf()/producer path: | |
1259 | * caller holds non-exclusive termios_rwsem | |
1260 | * publishes canon_head if canonical mode is active | |
e60d27c4 PH |
1261 | * |
1262 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1263 | */ |
1264 | ||
e60d27c4 | 1265 | static int |
4b1f79c2 | 1266 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1267 | { |
53c5ee2c | 1268 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1269 | |
1da177e4 LT |
1270 | if (I_IXON(tty)) { |
1271 | if (c == START_CHAR(tty)) { | |
1272 | start_tty(tty); | |
e2613be5 | 1273 | process_echoes(tty); |
e60d27c4 | 1274 | return 0; |
1da177e4 LT |
1275 | } |
1276 | if (c == STOP_CHAR(tty)) { | |
1277 | stop_tty(tty); | |
e60d27c4 | 1278 | return 0; |
1da177e4 LT |
1279 | } |
1280 | } | |
575537b3 | 1281 | |
1da177e4 | 1282 | if (L_ISIG(tty)) { |
b0ac50be PH |
1283 | if (c == INTR_CHAR(tty)) { |
1284 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1285 | return 0; |
b0ac50be PH |
1286 | } else if (c == QUIT_CHAR(tty)) { |
1287 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1288 | return 0; |
b0ac50be PH |
1289 | } else if (c == SUSP_CHAR(tty)) { |
1290 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1291 | return 0; |
1da177e4 LT |
1292 | } |
1293 | } | |
575537b3 | 1294 | |
855df3c0 PH |
1295 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1296 | start_tty(tty); | |
1297 | process_echoes(tty); | |
1298 | } | |
1299 | ||
575537b3 JP |
1300 | if (c == '\r') { |
1301 | if (I_IGNCR(tty)) | |
e60d27c4 | 1302 | return 0; |
575537b3 JP |
1303 | if (I_ICRNL(tty)) |
1304 | c = '\n'; | |
1305 | } else if (c == '\n' && I_INLCR(tty)) | |
1306 | c = '\r'; | |
1307 | ||
53c5ee2c | 1308 | if (ldata->icanon) { |
1da177e4 LT |
1309 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1310 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1311 | eraser(c, tty); | |
17bd7907 | 1312 | commit_echoes(tty); |
e60d27c4 | 1313 | return 0; |
1da177e4 LT |
1314 | } |
1315 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1316 | ldata->lnext = 1; |
1da177e4 | 1317 | if (L_ECHO(tty)) { |
57c94121 | 1318 | finish_erasing(ldata); |
1da177e4 | 1319 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1320 | echo_char_raw('^', ldata); |
1321 | echo_char_raw('\b', ldata); | |
17bd7907 | 1322 | commit_echoes(tty); |
1da177e4 LT |
1323 | } |
1324 | } | |
e60d27c4 | 1325 | return 1; |
1da177e4 | 1326 | } |
e60d27c4 | 1327 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1328 | size_t tail = ldata->canon_head; |
1da177e4 | 1329 | |
57c94121 | 1330 | finish_erasing(ldata); |
1da177e4 | 1331 | echo_char(c, tty); |
57c94121 | 1332 | echo_char_raw('\n', ldata); |
ba2e68ac | 1333 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1334 | echo_char(read_buf(ldata, tail), tty); |
1335 | tail++; | |
1da177e4 | 1336 | } |
17bd7907 | 1337 | commit_echoes(tty); |
e60d27c4 | 1338 | return 0; |
1da177e4 LT |
1339 | } |
1340 | if (c == '\n') { | |
acc71bba | 1341 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1342 | echo_char_raw('\n', ldata); |
17bd7907 | 1343 | commit_echoes(tty); |
1da177e4 LT |
1344 | } |
1345 | goto handle_newline; | |
1346 | } | |
1347 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1348 | c = __DISABLED_CHAR; |
1349 | goto handle_newline; | |
1350 | } | |
1351 | if ((c == EOL_CHAR(tty)) || | |
1352 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1353 | /* | |
1354 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1355 | */ | |
1356 | if (L_ECHO(tty)) { | |
1da177e4 | 1357 | /* Record the column of first canon char. */ |
ba2e68ac | 1358 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1359 | echo_set_canon_col(ldata); |
1da177e4 | 1360 | echo_char(c, tty); |
17bd7907 | 1361 | commit_echoes(tty); |
1da177e4 LT |
1362 | } |
1363 | /* | |
1364 | * XXX does PARMRK doubling happen for | |
1365 | * EOL_CHAR and EOL2_CHAR? | |
1366 | */ | |
001ba923 | 1367 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
57c94121 | 1368 | put_tty_queue(c, ldata); |
1da177e4 | 1369 | |
4edf1827 | 1370 | handle_newline: |
bc5a5e3f | 1371 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1372 | put_tty_queue(c, ldata); |
70aca71f | 1373 | smp_store_release(&ldata->canon_head, ldata->read_head); |
1da177e4 LT |
1374 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1375 | if (waitqueue_active(&tty->read_wait)) | |
57087d51 | 1376 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
e60d27c4 | 1377 | return 0; |
1da177e4 LT |
1378 | } |
1379 | } | |
4edf1827 | 1380 | |
acc71bba | 1381 | if (L_ECHO(tty)) { |
57c94121 | 1382 | finish_erasing(ldata); |
1da177e4 | 1383 | if (c == '\n') |
57c94121 | 1384 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1385 | else { |
1386 | /* Record the column of first canon char. */ | |
ba2e68ac | 1387 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1388 | echo_set_canon_col(ldata); |
1da177e4 LT |
1389 | echo_char(c, tty); |
1390 | } | |
17bd7907 | 1391 | commit_echoes(tty); |
1da177e4 LT |
1392 | } |
1393 | ||
001ba923 PH |
1394 | /* PARMRK doubling check */ |
1395 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
57c94121 | 1396 | put_tty_queue(c, ldata); |
1da177e4 | 1397 | |
57c94121 | 1398 | put_tty_queue(c, ldata); |
e60d27c4 | 1399 | return 0; |
4edf1827 | 1400 | } |
1da177e4 | 1401 | |
e60d27c4 PH |
1402 | static inline void |
1403 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1404 | { |
1405 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1406 | |
e60d27c4 PH |
1407 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1408 | start_tty(tty); | |
1409 | process_echoes(tty); | |
1410 | } | |
1411 | if (L_ECHO(tty)) { | |
1412 | finish_erasing(ldata); | |
1413 | /* Record the column of first canon char. */ | |
1414 | if (ldata->canon_head == ldata->read_head) | |
1415 | echo_set_canon_col(ldata); | |
1416 | echo_char(c, tty); | |
1417 | commit_echoes(tty); | |
4b1f79c2 | 1418 | } |
001ba923 PH |
1419 | /* PARMRK doubling check */ |
1420 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
e60d27c4 PH |
1421 | put_tty_queue(c, ldata); |
1422 | put_tty_queue(c, ldata); | |
1423 | } | |
4b1f79c2 | 1424 | |
eb3e4668 | 1425 | static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
e60d27c4 PH |
1426 | { |
1427 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1428 | } |
1429 | ||
7de971b0 PH |
1430 | static inline void |
1431 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1432 | { | |
1433 | struct n_tty_data *ldata = tty->disc_data; | |
1434 | ||
e60d27c4 PH |
1435 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1436 | start_tty(tty); | |
1437 | process_echoes(tty); | |
7de971b0 | 1438 | } |
e60d27c4 PH |
1439 | if (L_ECHO(tty)) { |
1440 | finish_erasing(ldata); | |
1441 | /* Record the column of first canon char. */ | |
1442 | if (ldata->canon_head == ldata->read_head) | |
1443 | echo_set_canon_col(ldata); | |
1444 | echo_char(c, tty); | |
1445 | commit_echoes(tty); | |
1446 | } | |
1447 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1448 | } |
1449 | ||
8dc4b25d | 1450 | static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) |
ad0cc7ba PH |
1451 | { |
1452 | if (I_ISTRIP(tty)) | |
1453 | c &= 0x7f; | |
1454 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1455 | c = tolower(c); | |
1456 | ||
1457 | if (I_IXON(tty)) { | |
1458 | if (c == STOP_CHAR(tty)) | |
1459 | stop_tty(tty); | |
1460 | else if (c == START_CHAR(tty) || | |
1461 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1462 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1463 | c != SUSP_CHAR(tty))) { | |
1464 | start_tty(tty); | |
1465 | process_echoes(tty); | |
1466 | } | |
1467 | } | |
1468 | } | |
1469 | ||
d2f8d7ab PH |
1470 | static void |
1471 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1472 | { | |
d2f8d7ab PH |
1473 | switch (flag) { |
1474 | case TTY_BREAK: | |
1475 | n_tty_receive_break(tty); | |
1476 | break; | |
1477 | case TTY_PARITY: | |
1478 | case TTY_FRAME: | |
1479 | n_tty_receive_parity_error(tty, c); | |
1480 | break; | |
1481 | case TTY_OVERRUN: | |
1482 | n_tty_receive_overrun(tty); | |
1483 | break; | |
1484 | default: | |
1485 | printk(KERN_ERR "%s: unknown flag %d\n", | |
429b4749 | 1486 | tty_name(tty), flag); |
d2f8d7ab PH |
1487 | break; |
1488 | } | |
1489 | } | |
1490 | ||
e60d27c4 PH |
1491 | static void |
1492 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1493 | { | |
1494 | struct n_tty_data *ldata = tty->disc_data; | |
1495 | ||
1496 | ldata->lnext = 0; | |
1497 | if (likely(flag == TTY_NORMAL)) { | |
1498 | if (I_ISTRIP(tty)) | |
1499 | c &= 0x7f; | |
1500 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1501 | c = tolower(c); | |
1502 | n_tty_receive_char(tty, c); | |
1503 | } else | |
1504 | n_tty_receive_char_flagged(tty, c, flag); | |
1505 | } | |
1506 | ||
4a23a4df PH |
1507 | static void |
1508 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1509 | char *fp, int count) | |
1510 | { | |
1511 | struct n_tty_data *ldata = tty->disc_data; | |
1512 | size_t n, head; | |
1513 | ||
1514 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1515 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1516 | memcpy(read_buf_addr(ldata, head), cp, n); |
1517 | ldata->read_head += n; | |
1518 | cp += n; | |
1519 | count -= n; | |
1520 | ||
1521 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1522 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1523 | memcpy(read_buf_addr(ldata, head), cp, n); |
1524 | ldata->read_head += n; | |
1525 | } | |
1526 | ||
554117bd PH |
1527 | static void |
1528 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1529 | char *fp, int count) | |
1530 | { | |
1531 | struct n_tty_data *ldata = tty->disc_data; | |
1532 | char flag = TTY_NORMAL; | |
1533 | ||
1534 | while (count--) { | |
1535 | if (fp) | |
1536 | flag = *fp++; | |
1537 | if (likely(flag == TTY_NORMAL)) | |
1538 | put_tty_queue(*cp++, ldata); | |
1539 | else | |
1540 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1541 | } | |
1542 | } | |
1543 | ||
ad0cc7ba PH |
1544 | static void |
1545 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1546 | char *fp, int count) | |
1547 | { | |
1548 | char flag = TTY_NORMAL; | |
1549 | ||
1550 | while (count--) { | |
1551 | if (fp) | |
1552 | flag = *fp++; | |
1553 | if (likely(flag == TTY_NORMAL)) | |
1554 | n_tty_receive_char_closing(tty, *cp++); | |
1555 | else | |
1556 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1557 | } | |
1558 | } | |
1559 | ||
7d88d637 PH |
1560 | static void |
1561 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1562 | char *fp, int count) |
1563 | { | |
1564 | struct n_tty_data *ldata = tty->disc_data; | |
1565 | char flag = TTY_NORMAL; | |
1566 | ||
1567 | while (count--) { | |
1568 | if (fp) | |
1569 | flag = *fp++; | |
1570 | if (likely(flag == TTY_NORMAL)) { | |
1571 | unsigned char c = *cp++; | |
1572 | ||
1573 | if (I_ISTRIP(tty)) | |
1574 | c &= 0x7f; | |
1575 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1576 | c = tolower(c); | |
1577 | if (L_EXTPROC(tty)) { | |
1578 | put_tty_queue(c, ldata); | |
1579 | continue; | |
1580 | } | |
e60d27c4 PH |
1581 | if (!test_bit(c, ldata->char_map)) |
1582 | n_tty_receive_char_inline(tty, c); | |
1583 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1584 | if (fp) | |
1585 | flag = *fp++; | |
1586 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1587 | count--; | |
1588 | } | |
6baad008 PH |
1589 | } else |
1590 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1591 | } | |
1592 | } | |
1593 | ||
1594 | static void | |
1595 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1596 | char *fp, int count) | |
7d88d637 | 1597 | { |
e60d27c4 | 1598 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1599 | char flag = TTY_NORMAL; |
1600 | ||
1601 | while (count--) { | |
1602 | if (fp) | |
1603 | flag = *fp++; | |
e60d27c4 PH |
1604 | if (likely(flag == TTY_NORMAL)) { |
1605 | unsigned char c = *cp++; | |
1606 | ||
1607 | if (!test_bit(c, ldata->char_map)) | |
1608 | n_tty_receive_char_fast(tty, c); | |
1609 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1610 | if (fp) | |
1611 | flag = *fp++; | |
1612 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1613 | count--; | |
1614 | } | |
1615 | } else | |
7d88d637 PH |
1616 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1617 | } | |
1618 | } | |
1619 | ||
24a89d1c PH |
1620 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1621 | char *fp, int count) | |
1da177e4 | 1622 | { |
53c5ee2c | 1623 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1624 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1625 | |
4a23a4df PH |
1626 | if (ldata->real_raw) |
1627 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1628 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1629 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1630 | else if (tty->closing && !L_EXTPROC(tty)) |
1631 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1632 | else { |
e60d27c4 PH |
1633 | if (ldata->lnext) { |
1634 | char flag = TTY_NORMAL; | |
1635 | ||
1636 | if (fp) | |
1637 | flag = *fp++; | |
1638 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1639 | count--; | |
1640 | } | |
1641 | ||
7de971b0 | 1642 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1643 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1644 | else | |
1645 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1646 | |
1647 | flush_echoes(tty); | |
f34d7a5b AC |
1648 | if (tty->ops->flush_chars) |
1649 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1650 | } |
1651 | ||
70aca71f PH |
1652 | if (ldata->icanon && !L_EXTPROC(tty)) |
1653 | return; | |
1654 | ||
1655 | /* publish read_head to consumer */ | |
1656 | smp_store_release(&ldata->commit_head, ldata->read_head); | |
1657 | ||
1658 | if ((read_cnt(ldata) >= ldata->minimum_to_wake) || L_EXTPROC(tty)) { | |
1da177e4 LT |
1659 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1660 | if (waitqueue_active(&tty->read_wait)) | |
57087d51 | 1661 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 | 1662 | } |
1da177e4 LT |
1663 | } |
1664 | ||
fb5ef9e7 PH |
1665 | /** |
1666 | * n_tty_receive_buf_common - process input | |
1667 | * @tty: device to receive input | |
1668 | * @cp: input chars | |
1669 | * @fp: flags for each char (if NULL, all chars are TTY_NORMAL) | |
1670 | * @count: number of input chars in @cp | |
1671 | * | |
1672 | * Called by the terminal driver when a block of characters has | |
1673 | * been received. This function must be called from soft contexts | |
1674 | * not from interrupt context. The driver is responsible for making | |
1675 | * calls one at a time and in order (or using flush_to_ldisc) | |
1676 | * | |
1677 | * Returns the # of input chars from @cp which were processed. | |
1678 | * | |
1679 | * In canonical mode, the maximum line length is 4096 chars (including | |
1680 | * the line termination char); lines longer than 4096 chars are | |
1681 | * truncated. After 4095 chars, input data is still processed but | |
1682 | * not stored. Overflow processing ensures the tty can always | |
1683 | * receive more input until at least one line can be read. | |
1684 | * | |
1685 | * In non-canonical mode, the read buffer will only accept 4095 chars; | |
1686 | * this provides the necessary space for a newline char if the input | |
1687 | * mode is switched to canonical. | |
1688 | * | |
1689 | * Note it is possible for the read buffer to _contain_ 4096 chars | |
1690 | * in non-canonical mode: the read buffer could already contain the | |
1691 | * maximum canon line of 4096 chars when the mode is switched to | |
1692 | * non-canonical. | |
1693 | * | |
1694 | * n_tty_receive_buf()/producer path: | |
1695 | * claims non-exclusive termios_rwsem | |
1696 | * publishes commit_head or canon_head | |
1697 | */ | |
5c32d123 PH |
1698 | static int |
1699 | n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, | |
1700 | char *fp, int count, int flow) | |
24a89d1c PH |
1701 | { |
1702 | struct n_tty_data *ldata = tty->disc_data; | |
fb5ef9e7 | 1703 | int room, n, rcvd = 0, overflow; |
24a89d1c | 1704 | |
9356b535 PH |
1705 | down_read(&tty->termios_rwsem); |
1706 | ||
19e2ad6a | 1707 | while (1) { |
70aca71f | 1708 | /* |
06c49f9f PH |
1709 | * When PARMRK is set, each input char may take up to 3 chars |
1710 | * in the read buf; reduce the buffer space avail by 3x | |
70aca71f PH |
1711 | * |
1712 | * If we are doing input canonicalization, and there are no | |
1713 | * pending newlines, let characters through without limit, so | |
1714 | * that erase characters will be handled. Other excess | |
1715 | * characters will be beeped. | |
1716 | * | |
1717 | * paired with store in *_copy_from_read_buf() -- guarantees | |
1718 | * the consumer has loaded the data in read_buf up to the new | |
1719 | * read_tail (so this producer will not overwrite unread data) | |
1720 | */ | |
1721 | size_t tail = smp_load_acquire(&ldata->read_tail); | |
70aca71f | 1722 | |
fb5ef9e7 | 1723 | room = N_TTY_BUF_SIZE - (ldata->read_head - tail); |
70aca71f | 1724 | if (I_PARMRK(tty)) |
fb5ef9e7 PH |
1725 | room = (room + 2) / 3; |
1726 | room--; | |
1727 | if (room <= 0) { | |
1728 | overflow = ldata->icanon && ldata->canon_head == tail; | |
1729 | if (overflow && room < 0) | |
1730 | ldata->read_head--; | |
1731 | room = overflow; | |
1732 | ldata->no_room = flow && !room; | |
1733 | } else | |
1734 | overflow = 0; | |
70aca71f | 1735 | |
19e2ad6a | 1736 | n = min(count, room); |
fb5ef9e7 | 1737 | if (!n) |
19e2ad6a | 1738 | break; |
fb5ef9e7 PH |
1739 | |
1740 | /* ignore parity errors if handling overflow */ | |
1741 | if (!overflow || !fp || *fp != TTY_PARITY) | |
1742 | __receive_buf(tty, cp, fp, n); | |
1743 | ||
19e2ad6a PH |
1744 | cp += n; |
1745 | if (fp) | |
1746 | fp += n; | |
1747 | count -= n; | |
1748 | rcvd += n; | |
4a23a4df | 1749 | } |
24a89d1c | 1750 | |
19e2ad6a | 1751 | tty->receive_room = room; |
fb5ef9e7 PH |
1752 | |
1753 | /* Unthrottle if handling overflow on pty */ | |
1754 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { | |
1755 | if (overflow) { | |
1756 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1757 | tty_unthrottle_safe(tty); | |
1758 | __tty_set_flow_change(tty, 0); | |
1759 | } | |
1760 | } else | |
1761 | n_tty_check_throttle(tty); | |
1762 | ||
9356b535 PH |
1763 | up_read(&tty->termios_rwsem); |
1764 | ||
19e2ad6a | 1765 | return rcvd; |
24a89d1c PH |
1766 | } |
1767 | ||
5c32d123 PH |
1768 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1769 | char *fp, int count) | |
1770 | { | |
1771 | n_tty_receive_buf_common(tty, cp, fp, count, 0); | |
1772 | } | |
1773 | ||
1774 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1775 | char *fp, int count) | |
1776 | { | |
1777 | return n_tty_receive_buf_common(tty, cp, fp, count, 1); | |
1778 | } | |
1779 | ||
1da177e4 LT |
1780 | int is_ignored(int sig) |
1781 | { | |
1782 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1783 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1784 | } |
1785 | ||
1786 | /** | |
1787 | * n_tty_set_termios - termios data changed | |
1788 | * @tty: terminal | |
1789 | * @old: previous data | |
1790 | * | |
1791 | * Called by the tty layer when the user changes termios flags so | |
1792 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1793 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1794 | * guaranteed that this function will not be re-entered or in progress |
1795 | * when the ldisc is closed. | |
17b82060 | 1796 | * |
6a1c0680 | 1797 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1798 | */ |
4edf1827 AC |
1799 | |
1800 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1801 | { |
53c5ee2c | 1802 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1803 | |
c786f74e | 1804 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { |
3fe780b3 | 1805 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1806 | ldata->line_start = ldata->read_tail; |
1807 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1808 | ldata->canon_head = ldata->read_tail; | |
1809 | ldata->push = 0; | |
1810 | } else { | |
1811 | set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), | |
1812 | ldata->read_flags); | |
1813 | ldata->canon_head = ldata->read_head; | |
1814 | ldata->push = 1; | |
1815 | } | |
70aca71f | 1816 | ldata->commit_head = ldata->read_head; |
53c5ee2c | 1817 | ldata->erasing = 0; |
6f9b028a | 1818 | ldata->lnext = 0; |
47afa7a5 AC |
1819 | } |
1820 | ||
53c5ee2c | 1821 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1822 | |
1da177e4 LT |
1823 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1824 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1825 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1826 | I_PARMRK(tty)) { | |
1bb9d562 | 1827 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1828 | |
1829 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1830 | set_bit('\r', ldata->char_map); |
1da177e4 | 1831 | if (I_INLCR(tty)) |
1bb9d562 | 1832 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1833 | |
1834 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1835 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1836 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1837 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1838 | set_bit('\n', ldata->char_map); | |
1839 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1840 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1841 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1842 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1843 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1844 | if (L_ECHO(tty)) |
1845 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1846 | ldata->char_map); |
1da177e4 LT |
1847 | } |
1848 | } | |
1849 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1850 | set_bit(START_CHAR(tty), ldata->char_map); |
1851 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1852 | } |
1853 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1854 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1855 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1856 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1857 | } |
1bb9d562 | 1858 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1859 | ldata->raw = 0; |
1860 | ldata->real_raw = 0; | |
1da177e4 | 1861 | } else { |
53c5ee2c | 1862 | ldata->raw = 1; |
1da177e4 LT |
1863 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1864 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1865 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1866 | ldata->real_raw = 1; |
1da177e4 | 1867 | else |
53c5ee2c | 1868 | ldata->real_raw = 0; |
1da177e4 | 1869 | } |
dab73b4e WY |
1870 | /* |
1871 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1872 | * been stopped by STOP_CHAR(tty) before it. | |
1873 | */ | |
e2613be5 | 1874 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { |
dab73b4e | 1875 | start_tty(tty); |
e2613be5 PH |
1876 | process_echoes(tty); |
1877 | } | |
dab73b4e | 1878 | |
f34d7a5b | 1879 | /* The termios change make the tty ready for I/O */ |
6c67716d PH |
1880 | if (waitqueue_active(&tty->write_wait)) |
1881 | wake_up_interruptible(&tty->write_wait); | |
1882 | if (waitqueue_active(&tty->read_wait)) | |
1883 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1884 | } |
1885 | ||
1886 | /** | |
1887 | * n_tty_close - close the ldisc for this tty | |
1888 | * @tty: device | |
1889 | * | |
4edf1827 AC |
1890 | * Called from the terminal layer when this line discipline is |
1891 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1892 | * discipline change. The function will not be called while other |
1893 | * ldisc methods are in progress. | |
1894 | */ | |
4edf1827 | 1895 | |
1da177e4 LT |
1896 | static void n_tty_close(struct tty_struct *tty) |
1897 | { | |
70ece7a7 JS |
1898 | struct n_tty_data *ldata = tty->disc_data; |
1899 | ||
79901317 PH |
1900 | if (tty->link) |
1901 | n_tty_packet_mode_flush(tty); | |
1902 | ||
20bafb3d | 1903 | vfree(ldata); |
70ece7a7 | 1904 | tty->disc_data = NULL; |
1da177e4 LT |
1905 | } |
1906 | ||
1907 | /** | |
1908 | * n_tty_open - open an ldisc | |
1909 | * @tty: terminal to open | |
1910 | * | |
4edf1827 | 1911 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1912 | * terminal device. Can sleep. Called serialized so that no |
1913 | * other events will occur in parallel. No further open will occur | |
1914 | * until a close. | |
1915 | */ | |
1916 | ||
1917 | static int n_tty_open(struct tty_struct *tty) | |
1918 | { | |
70ece7a7 JS |
1919 | struct n_tty_data *ldata; |
1920 | ||
20bafb3d PH |
1921 | /* Currently a malloc failure here can panic */ |
1922 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1923 | if (!ldata) |
1924 | goto err; | |
1925 | ||
53c5ee2c | 1926 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1927 | mutex_init(&ldata->atomic_read_lock); |
1928 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1929 | |
70ece7a7 | 1930 | tty->disc_data = ldata; |
b66f4fa5 | 1931 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1932 | ldata->column = 0; |
20bafb3d | 1933 | ldata->canon_column = 0; |
f6c8dbe6 | 1934 | ldata->minimum_to_wake = 1; |
20bafb3d PH |
1935 | ldata->num_overrun = 0; |
1936 | ldata->no_room = 0; | |
1937 | ldata->lnext = 0; | |
1da177e4 | 1938 | tty->closing = 0; |
b66f4fa5 PH |
1939 | /* indicate buffer work may resume */ |
1940 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1941 | n_tty_set_termios(tty, NULL); | |
1942 | tty_unthrottle(tty); | |
70ece7a7 | 1943 | |
1da177e4 | 1944 | return 0; |
70ece7a7 | 1945 | err: |
b91939f5 | 1946 | return -ENOMEM; |
1da177e4 LT |
1947 | } |
1948 | ||
eafbe67f | 1949 | static inline int input_available_p(struct tty_struct *tty, int poll) |
1da177e4 | 1950 | { |
53c5ee2c | 1951 | struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1952 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1953 | |
25e8d0ed PH |
1954 | if (ldata->icanon && !L_EXTPROC(tty)) |
1955 | return ldata->canon_head != ldata->read_tail; | |
1956 | else | |
70aca71f | 1957 | return ldata->commit_head - ldata->read_tail >= amt; |
1da177e4 LT |
1958 | } |
1959 | ||
1a48632f PH |
1960 | static inline int check_other_done(struct tty_struct *tty) |
1961 | { | |
1962 | int done = test_bit(TTY_OTHER_DONE, &tty->flags); | |
1963 | if (done) { | |
1964 | /* paired with cmpxchg() in check_other_closed(); ensures | |
1965 | * read buffer head index is not stale | |
1966 | */ | |
1967 | smp_mb__after_atomic(); | |
1968 | } | |
1969 | return done; | |
1970 | } | |
1971 | ||
1da177e4 | 1972 | /** |
bbd20759 | 1973 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1974 | * @tty: terminal device |
1975 | * @b: user data | |
1976 | * @nr: size of data | |
1977 | * | |
11a96d18 | 1978 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1979 | * ICANON is off; it copies characters straight from the tty queue to |
1980 | * user space directly. It can be profitably called twice; once to | |
1981 | * drain the space from the tail pointer to the (physical) end of the | |
1982 | * buffer, and once to drain the space from the (physical) beginning of | |
1983 | * the buffer to head pointer. | |
1984 | * | |
bddc7152 | 1985 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1986 | * |
6d76bd26 PH |
1987 | * n_tty_read()/consumer path: |
1988 | * caller holds non-exclusive termios_rwsem | |
1989 | * read_tail published | |
1da177e4 | 1990 | */ |
4edf1827 | 1991 | |
33f0f88f | 1992 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1993 | unsigned char __user **b, |
1994 | size_t *nr) | |
1995 | ||
1996 | { | |
53c5ee2c | 1997 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1998 | int retval; |
1999 | size_t n; | |
3fa10cc8 | 2000 | bool is_eof; |
70aca71f | 2001 | size_t head = smp_load_acquire(&ldata->commit_head); |
bc5a5e3f | 2002 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
2003 | |
2004 | retval = 0; | |
70aca71f | 2005 | n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail); |
1da177e4 | 2006 | n = min(*nr, n); |
1da177e4 | 2007 | if (n) { |
bc5a5e3f | 2008 | retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
1da177e4 | 2009 | n -= retval; |
bc5a5e3f PH |
2010 | is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); |
2011 | tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, | |
53c5ee2c | 2012 | ldata->icanon); |
70aca71f | 2013 | smp_store_release(&ldata->read_tail, ldata->read_tail + n); |
26df6d13 | 2014 | /* Turn single EOF into zero-length read */ |
70aca71f PH |
2015 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && |
2016 | (head == ldata->read_tail)) | |
3fa10cc8 | 2017 | n = 0; |
1da177e4 LT |
2018 | *b += n; |
2019 | *nr -= n; | |
2020 | } | |
2021 | return retval; | |
2022 | } | |
2023 | ||
88bb0de3 | 2024 | /** |
32f13521 | 2025 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
2026 | * @tty: terminal device |
2027 | * @b: user data | |
2028 | * @nr: size of data | |
2029 | * | |
2030 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
2031 | * it copies one line of input up to and including the line-delimiting |
2032 | * character into the user-space buffer. | |
88bb0de3 | 2033 | * |
4d0ed182 PH |
2034 | * NB: When termios is changed from non-canonical to canonical mode and |
2035 | * the read buffer contains data, n_tty_set_termios() simulates an EOF | |
2036 | * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. | |
2037 | * This causes data already processed as input to be immediately available | |
2038 | * as input although a newline has not been received. | |
2039 | * | |
88bb0de3 | 2040 | * Called under the atomic_read_lock mutex |
6d76bd26 PH |
2041 | * |
2042 | * n_tty_read()/consumer path: | |
2043 | * caller holds non-exclusive termios_rwsem | |
2044 | * read_tail published | |
88bb0de3 PH |
2045 | */ |
2046 | ||
32f13521 PH |
2047 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
2048 | unsigned char __user **b, | |
2049 | size_t *nr) | |
88bb0de3 PH |
2050 | { |
2051 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 2052 | size_t n, size, more, c; |
bc5a5e3f PH |
2053 | size_t eol; |
2054 | size_t tail; | |
2055 | int ret, found = 0; | |
40d5e090 | 2056 | bool eof_push = 0; |
88bb0de3 PH |
2057 | |
2058 | /* N.B. avoid overrun if nr == 0 */ | |
70aca71f | 2059 | n = min(*nr, smp_load_acquire(&ldata->canon_head) - ldata->read_tail); |
6d76bd26 | 2060 | if (!n) |
32f13521 | 2061 | return 0; |
88bb0de3 | 2062 | |
bc5a5e3f | 2063 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
2064 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
2065 | ||
bc5a5e3f | 2066 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2067 | __func__, *nr, tail, n, size); |
2068 | ||
2069 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2070 | more = n - (size - tail); | |
2071 | if (eol == N_TTY_BUF_SIZE && more) { | |
2072 | /* scan wrapped without finding set bit */ | |
2073 | eol = find_next_bit(ldata->read_flags, more, 0); | |
2074 | if (eol != more) | |
2075 | found = 1; | |
2076 | } else if (eol != size) | |
2077 | found = 1; | |
2078 | ||
2079 | size = N_TTY_BUF_SIZE - tail; | |
c77569d2 | 2080 | n = eol - tail; |
da555db6 MT |
2081 | if (n > N_TTY_BUF_SIZE) |
2082 | n += N_TTY_BUF_SIZE; | |
c77569d2 | 2083 | n += found; |
32f13521 PH |
2084 | c = n; |
2085 | ||
4d0ed182 | 2086 | if (found && !ldata->push && read_buf(ldata, eol) == __DISABLED_CHAR) { |
32f13521 | 2087 | n--; |
40d5e090 PH |
2088 | eof_push = !n && ldata->read_tail != ldata->line_start; |
2089 | } | |
32f13521 | 2090 | |
bc5a5e3f | 2091 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", |
32f13521 PH |
2092 | __func__, eol, found, n, c, size, more); |
2093 | ||
32f13521 | 2094 | if (n > size) { |
72586c60 | 2095 | ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), size); |
32f13521 PH |
2096 | if (ret) |
2097 | return -EFAULT; | |
72586c60 | 2098 | ret = tty_copy_to_user(tty, *b + size, ldata->read_buf, n - size); |
32f13521 | 2099 | } else |
72586c60 | 2100 | ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), n); |
32f13521 PH |
2101 | |
2102 | if (ret) | |
2103 | return -EFAULT; | |
2104 | *b += n; | |
2105 | *nr -= n; | |
2106 | ||
a73d3d69 | 2107 | if (found) |
6d76bd26 | 2108 | clear_bit(eol, ldata->read_flags); |
70aca71f | 2109 | smp_store_release(&ldata->read_tail, ldata->read_tail + c); |
88bb0de3 | 2110 | |
40d5e090 | 2111 | if (found) { |
4d0ed182 PH |
2112 | if (!ldata->push) |
2113 | ldata->line_start = ldata->read_tail; | |
2114 | else | |
2115 | ldata->push = 0; | |
32f13521 | 2116 | tty_audit_push(tty); |
40d5e090 PH |
2117 | } |
2118 | return eof_push ? -EAGAIN : 0; | |
88bb0de3 PH |
2119 | } |
2120 | ||
cc4191dc | 2121 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2122 | size_t, loff_t *); |
1da177e4 LT |
2123 | |
2124 | /** | |
2125 | * job_control - check job control | |
2126 | * @tty: tty | |
2127 | * @file: file handle | |
2128 | * | |
2129 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2130 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2131 | * error code if action should be taken. |
04f378b1 | 2132 | * |
01a5e440 PH |
2133 | * Locking: redirected write test is safe |
2134 | * current->signal->tty check is safe | |
2135 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2136 | */ |
4edf1827 | 2137 | |
1da177e4 LT |
2138 | static int job_control(struct tty_struct *tty, struct file *file) |
2139 | { | |
2140 | /* Job control check -- must be done at start and after | |
2141 | every sleep (POSIX.1 7.1.1.4). */ | |
2142 | /* NOTE: not yet done after every sleep pending a thorough | |
2143 | check of the logic of this change. -- jlc */ | |
2144 | /* don't stop on /dev/console */ | |
01a5e440 PH |
2145 | if (file->f_op->write == redirected_tty_write || |
2146 | current->signal->tty != tty) | |
2147 | return 0; | |
2148 | ||
2149 | spin_lock_irq(&tty->ctrl_lock); | |
2150 | if (!tty->pgrp) | |
2151 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
2152 | else if (task_pgrp(current) != tty->pgrp) { | |
2153 | spin_unlock_irq(&tty->ctrl_lock); | |
2154 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
2155 | return -EIO; | |
2156 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
2157 | set_thread_flag(TIF_SIGPENDING); | |
2158 | return -ERESTARTSYS; | |
1da177e4 | 2159 | } |
01a5e440 | 2160 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
2161 | return 0; |
2162 | } | |
4edf1827 | 2163 | |
1da177e4 LT |
2164 | |
2165 | /** | |
11a96d18 | 2166 | * n_tty_read - read function for tty |
1da177e4 LT |
2167 | * @tty: tty device |
2168 | * @file: file object | |
2169 | * @buf: userspace buffer pointer | |
2170 | * @nr: size of I/O | |
2171 | * | |
2172 | * Perform reads for the line discipline. We are guaranteed that the | |
2173 | * line discipline will not be closed under us but we may get multiple | |
2174 | * parallel readers and must handle this ourselves. We may also get | |
2175 | * a hangup. Always called in user context, may sleep. | |
2176 | * | |
2177 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2178 | * |
2179 | * n_tty_read()/consumer path: | |
2180 | * claims non-exclusive termios_rwsem | |
2181 | * publishes read_tail | |
1da177e4 | 2182 | */ |
4edf1827 | 2183 | |
11a96d18 | 2184 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2185 | unsigned char __user *buf, size_t nr) |
2186 | { | |
53c5ee2c | 2187 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 2188 | unsigned char __user *b = buf; |
97d9e28d | 2189 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1a48632f | 2190 | int c, done; |
1da177e4 LT |
2191 | int minimum, time; |
2192 | ssize_t retval = 0; | |
1da177e4 | 2193 | long timeout; |
04f378b1 | 2194 | int packet; |
2c5dc464 | 2195 | size_t tail; |
1da177e4 | 2196 | |
1da177e4 | 2197 | c = job_control(tty, file); |
4edf1827 | 2198 | if (c < 0) |
1da177e4 | 2199 | return c; |
4edf1827 | 2200 | |
aefceaf4 PH |
2201 | /* |
2202 | * Internal serialization of reads. | |
2203 | */ | |
2204 | if (file->f_flags & O_NONBLOCK) { | |
2205 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2206 | return -EAGAIN; | |
2207 | } else { | |
2208 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2209 | return -ERESTARTSYS; | |
2210 | } | |
2211 | ||
9356b535 PH |
2212 | down_read(&tty->termios_rwsem); |
2213 | ||
1da177e4 LT |
2214 | minimum = time = 0; |
2215 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2216 | if (!ldata->icanon) { |
1da177e4 LT |
2217 | minimum = MIN_CHAR(tty); |
2218 | if (minimum) { | |
a6e54319 | 2219 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2220 | if (time) |
f6c8dbe6 | 2221 | ldata->minimum_to_wake = 1; |
1da177e4 | 2222 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
2223 | (ldata->minimum_to_wake > minimum)) |
2224 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 2225 | } else { |
a6e54319 | 2226 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2227 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2228 | } |
2229 | } | |
2230 | ||
04f378b1 | 2231 | packet = tty->packet; |
2c5dc464 | 2232 | tail = ldata->read_tail; |
1da177e4 LT |
2233 | |
2234 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2235 | while (nr) { |
2236 | /* First test for status change. */ | |
04f378b1 | 2237 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2238 | unsigned char cs; |
2239 | if (b != buf) | |
2240 | break; | |
6054c16e | 2241 | spin_lock_irq(&tty->link->ctrl_lock); |
1da177e4 LT |
2242 | cs = tty->link->ctrl_status; |
2243 | tty->link->ctrl_status = 0; | |
6054c16e | 2244 | spin_unlock_irq(&tty->link->ctrl_lock); |
522ed776 | 2245 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2246 | retval = -EFAULT; |
2247 | b--; | |
2248 | break; | |
2249 | } | |
2250 | nr--; | |
2251 | break; | |
2252 | } | |
4edf1827 | 2253 | |
f6c8dbe6 | 2254 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2255 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2256 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2257 | |
1a48632f PH |
2258 | done = check_other_done(tty); |
2259 | ||
1da177e4 | 2260 | if (!input_available_p(tty, 0)) { |
1a48632f | 2261 | if (done) { |
52bce7f8 PH |
2262 | retval = -EIO; |
2263 | break; | |
f8747d4a | 2264 | } |
52bce7f8 PH |
2265 | if (tty_hung_up_p(file)) |
2266 | break; | |
2267 | if (!timeout) | |
2268 | break; | |
2269 | if (file->f_flags & O_NONBLOCK) { | |
2270 | retval = -EAGAIN; | |
1da177e4 LT |
2271 | break; |
2272 | } | |
52bce7f8 PH |
2273 | if (signal_pending(current)) { |
2274 | retval = -ERESTARTSYS; | |
2275 | break; | |
2276 | } | |
52bce7f8 | 2277 | up_read(&tty->termios_rwsem); |
9356b535 | 2278 | |
37da7bbb LT |
2279 | timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, |
2280 | timeout); | |
9356b535 | 2281 | |
52bce7f8 PH |
2282 | down_read(&tty->termios_rwsem); |
2283 | continue; | |
1da177e4 LT |
2284 | } |
2285 | ||
53c5ee2c | 2286 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2287 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
40d5e090 PH |
2288 | if (retval == -EAGAIN) { |
2289 | retval = 0; | |
2290 | continue; | |
2291 | } else if (retval) | |
1da177e4 LT |
2292 | break; |
2293 | } else { | |
2294 | int uncopied; | |
95ea90db PH |
2295 | |
2296 | /* Deal with packet mode. */ | |
2297 | if (packet && b == buf) { | |
2298 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { | |
2299 | retval = -EFAULT; | |
2300 | b--; | |
2301 | break; | |
2302 | } | |
2303 | nr--; | |
2304 | } | |
2305 | ||
1da177e4 LT |
2306 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2307 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2308 | if (uncopied) { | |
2309 | retval = -EFAULT; | |
2310 | break; | |
2311 | } | |
2312 | } | |
2313 | ||
6367ca72 | 2314 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2315 | |
2316 | if (b - buf >= minimum) | |
2317 | break; | |
2318 | if (time) | |
2319 | timeout = time; | |
2320 | } | |
2c5dc464 PH |
2321 | if (tail != ldata->read_tail) |
2322 | n_tty_kick_worker(tty); | |
42458f41 PH |
2323 | up_read(&tty->termios_rwsem); |
2324 | ||
1da177e4 | 2325 | remove_wait_queue(&tty->read_wait, &wait); |
1da177e4 | 2326 | if (!waitqueue_active(&tty->read_wait)) |
f6c8dbe6 | 2327 | ldata->minimum_to_wake = minimum; |
1da177e4 | 2328 | |
aebf0453 PH |
2329 | mutex_unlock(&ldata->atomic_read_lock); |
2330 | ||
40d5e090 PH |
2331 | if (b - buf) |
2332 | retval = b - buf; | |
1da177e4 LT |
2333 | |
2334 | return retval; | |
2335 | } | |
2336 | ||
2337 | /** | |
11a96d18 | 2338 | * n_tty_write - write function for tty |
1da177e4 LT |
2339 | * @tty: tty device |
2340 | * @file: file object | |
2341 | * @buf: userspace buffer pointer | |
2342 | * @nr: size of I/O | |
2343 | * | |
a88a69c9 | 2344 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2345 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2346 | * and other such events. Since the receive code will echo characters, |
2347 | * thus calling driver write methods, the output_lock is used in | |
2348 | * the output processing functions called here as well as in the | |
2349 | * echo processing function to protect the column state and space | |
2350 | * left in the buffer. | |
1da177e4 LT |
2351 | * |
2352 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2353 | * |
2354 | * Locking: output_lock to protect column state and space left | |
2355 | * (note that the process_output*() functions take this | |
2356 | * lock themselves) | |
1da177e4 | 2357 | */ |
4edf1827 | 2358 | |
11a96d18 | 2359 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2360 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2361 | { |
2362 | const unsigned char *b = buf; | |
97d9e28d | 2363 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2364 | int c; |
2365 | ssize_t retval = 0; | |
2366 | ||
2367 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2368 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2369 | retval = tty_check_change(tty); | |
2370 | if (retval) | |
2371 | return retval; | |
2372 | } | |
2373 | ||
9356b535 PH |
2374 | down_read(&tty->termios_rwsem); |
2375 | ||
a88a69c9 JP |
2376 | /* Write out any echoed characters that are still pending */ |
2377 | process_echoes(tty); | |
300a6204 | 2378 | |
1da177e4 LT |
2379 | add_wait_queue(&tty->write_wait, &wait); |
2380 | while (1) { | |
1da177e4 LT |
2381 | if (signal_pending(current)) { |
2382 | retval = -ERESTARTSYS; | |
2383 | break; | |
2384 | } | |
2385 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2386 | retval = -EIO; | |
2387 | break; | |
2388 | } | |
582f5590 | 2389 | if (O_OPOST(tty)) { |
1da177e4 | 2390 | while (nr > 0) { |
a88a69c9 | 2391 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2392 | if (num < 0) { |
2393 | if (num == -EAGAIN) | |
2394 | break; | |
2395 | retval = num; | |
2396 | goto break_out; | |
2397 | } | |
2398 | b += num; | |
2399 | nr -= num; | |
2400 | if (nr == 0) | |
2401 | break; | |
2402 | c = *b; | |
a88a69c9 | 2403 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2404 | break; |
2405 | b++; nr--; | |
2406 | } | |
f34d7a5b AC |
2407 | if (tty->ops->flush_chars) |
2408 | tty->ops->flush_chars(tty); | |
1da177e4 | 2409 | } else { |
4291086b PH |
2410 | struct n_tty_data *ldata = tty->disc_data; |
2411 | ||
d6afe27b | 2412 | while (nr > 0) { |
4291086b | 2413 | mutex_lock(&ldata->output_lock); |
f34d7a5b | 2414 | c = tty->ops->write(tty, b, nr); |
4291086b | 2415 | mutex_unlock(&ldata->output_lock); |
d6afe27b RZ |
2416 | if (c < 0) { |
2417 | retval = c; | |
2418 | goto break_out; | |
2419 | } | |
2420 | if (!c) | |
2421 | break; | |
2422 | b += c; | |
2423 | nr -= c; | |
1da177e4 | 2424 | } |
1da177e4 LT |
2425 | } |
2426 | if (!nr) | |
2427 | break; | |
2428 | if (file->f_flags & O_NONBLOCK) { | |
2429 | retval = -EAGAIN; | |
2430 | break; | |
2431 | } | |
9356b535 PH |
2432 | up_read(&tty->termios_rwsem); |
2433 | ||
97d9e28d | 2434 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
9356b535 PH |
2435 | |
2436 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2437 | } |
2438 | break_out: | |
1da177e4 | 2439 | remove_wait_queue(&tty->write_wait, &wait); |
ff8cb0fd TP |
2440 | if (b - buf != nr && tty->fasync) |
2441 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2442 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2443 | return (b - buf) ? b - buf : retval; |
2444 | } | |
2445 | ||
2446 | /** | |
11a96d18 | 2447 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2448 | * @tty: terminal device |
2449 | * @file: file accessing it | |
2450 | * @wait: poll table | |
2451 | * | |
2452 | * Called when the line discipline is asked to poll() for data or | |
2453 | * for special events. This code is not serialized with respect to | |
2454 | * other events save open/close. | |
2455 | * | |
2456 | * This code must be sure never to sleep through a hangup. | |
2457 | * Called without the kernel lock held - fine | |
1da177e4 | 2458 | */ |
4edf1827 | 2459 | |
11a96d18 | 2460 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2461 | poll_table *wait) |
1da177e4 | 2462 | { |
f6c8dbe6 | 2463 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2464 | unsigned int mask = 0; |
2465 | ||
2466 | poll_wait(file, &tty->read_wait, wait); | |
2467 | poll_wait(file, &tty->write_wait, wait); | |
1a48632f PH |
2468 | if (check_other_done(tty)) |
2469 | mask |= POLLHUP; | |
eafbe67f | 2470 | if (input_available_p(tty, 1)) |
1da177e4 LT |
2471 | mask |= POLLIN | POLLRDNORM; |
2472 | if (tty->packet && tty->link->ctrl_status) | |
2473 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
1da177e4 LT |
2474 | if (tty_hung_up_p(file)) |
2475 | mask |= POLLHUP; | |
2476 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2477 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2478 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2479 | else |
f6c8dbe6 | 2480 | ldata->minimum_to_wake = 1; |
1da177e4 | 2481 | } |
f34d7a5b AC |
2482 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2483 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2484 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2485 | mask |= POLLOUT | POLLWRNORM; |
2486 | return mask; | |
2487 | } | |
2488 | ||
57c94121 | 2489 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2490 | { |
bc5a5e3f | 2491 | size_t nr, head, tail; |
47afa7a5 | 2492 | |
a73d3d69 | 2493 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2494 | return 0; |
ba2e68ac JS |
2495 | head = ldata->canon_head; |
2496 | tail = ldata->read_tail; | |
bc5a5e3f | 2497 | nr = head - tail; |
47afa7a5 AC |
2498 | /* Skip EOF-chars.. */ |
2499 | while (head != tail) { | |
bc5a5e3f PH |
2500 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2501 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2502 | nr--; |
bc5a5e3f | 2503 | tail++; |
47afa7a5 AC |
2504 | } |
2505 | return nr; | |
2506 | } | |
2507 | ||
2508 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2509 | unsigned int cmd, unsigned long arg) | |
2510 | { | |
ba2e68ac | 2511 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2512 | int retval; |
2513 | ||
2514 | switch (cmd) { | |
2515 | case TIOCOUTQ: | |
2516 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2517 | case TIOCINQ: | |
6d76bd26 | 2518 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2519 | if (L_ICANON(tty)) |
57c94121 | 2520 | retval = inq_canon(ldata); |
6d76bd26 PH |
2521 | else |
2522 | retval = read_cnt(ldata); | |
2523 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2524 | return put_user(retval, (unsigned int __user *) arg); |
2525 | default: | |
2526 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2527 | } | |
2528 | } | |
2529 | ||
f6c8dbe6 PH |
2530 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2531 | { | |
2532 | struct n_tty_data *ldata = tty->disc_data; | |
2533 | ||
2534 | if (!waitqueue_active(&tty->read_wait)) { | |
2535 | if (on) | |
2536 | ldata->minimum_to_wake = 1; | |
2537 | else if (!tty->fasync) | |
2538 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2539 | } | |
2540 | } | |
2541 | ||
a352def2 | 2542 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2543 | .magic = TTY_LDISC_MAGIC, |
2544 | .name = "n_tty", | |
2545 | .open = n_tty_open, | |
2546 | .close = n_tty_close, | |
2547 | .flush_buffer = n_tty_flush_buffer, | |
2548 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2549 | .read = n_tty_read, |
2550 | .write = n_tty_write, | |
e10cc1df PF |
2551 | .ioctl = n_tty_ioctl, |
2552 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2553 | .poll = n_tty_poll, |
e10cc1df | 2554 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2555 | .write_wakeup = n_tty_write_wakeup, |
2556 | .fasync = n_tty_fasync, | |
24a89d1c | 2557 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2558 | }; |
572b9adb RG |
2559 | |
2560 | /** | |
2561 | * n_tty_inherit_ops - inherit N_TTY methods | |
2562 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2563 | * | |
593fb1ae | 2564 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2565 | * methods. |
2566 | */ | |
2567 | ||
2568 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2569 | { | |
2570 | *ops = tty_ldisc_N_TTY; | |
2571 | ops->owner = NULL; | |
2572 | ops->refcount = ops->flags = 0; | |
2573 | } | |
2574 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |