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 | ||
6b2a3d62 | 172 | tty_audit_add_data(tty, from, n, ldata->icanon); |
72586c60 LA |
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"); | |
e176058f | 204 | tty_buffer_restart_work(tty->port); |
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); |
e81107d4 | 346 | wake_up_interruptible(&tty->link->read_wait); |
a30737ab | 347 | } |
a30737ab PH |
348 | } |
349 | ||
1da177e4 LT |
350 | /** |
351 | * n_tty_flush_buffer - clean input queue | |
352 | * @tty: terminal device | |
353 | * | |
25518c68 PH |
354 | * Flush the input buffer. Called when the tty layer wants the |
355 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
356 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 357 | * |
6d76bd26 PH |
358 | * Holds termios_rwsem to exclude producer/consumer while |
359 | * buffer indices are reset. | |
360 | * | |
361 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 362 | */ |
4edf1827 AC |
363 | |
364 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 365 | { |
6d76bd26 | 366 | down_write(&tty->termios_rwsem); |
b66f4fa5 | 367 | reset_buffer_flags(tty->disc_data); |
2c5dc464 | 368 | n_tty_kick_worker(tty); |
4edf1827 | 369 | |
a30737ab PH |
370 | if (tty->link) |
371 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 372 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
373 | } |
374 | ||
6d76bd26 PH |
375 | /** |
376 | * n_tty_chars_in_buffer - report available bytes | |
377 | * @tty: tty device | |
378 | * | |
379 | * Report the number of characters buffered to be delivered to user | |
380 | * at this instant in time. | |
381 | * | |
382 | * Locking: exclusive termios_rwsem | |
383 | */ | |
384 | ||
a19d0c6a PH |
385 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
386 | { | |
6d76bd26 PH |
387 | ssize_t n; |
388 | ||
47534084 | 389 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
6d76bd26 PH |
390 | |
391 | down_write(&tty->termios_rwsem); | |
392 | n = chars_in_buffer(tty); | |
393 | up_write(&tty->termios_rwsem); | |
394 | return n; | |
a19d0c6a PH |
395 | } |
396 | ||
1da177e4 LT |
397 | /** |
398 | * is_utf8_continuation - utf8 multibyte check | |
399 | * @c: byte to check | |
400 | * | |
401 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
402 | * character. We use this to correctly compute the on screen size | |
403 | * of the character when printing | |
404 | */ | |
4edf1827 | 405 | |
1da177e4 LT |
406 | static inline int is_utf8_continuation(unsigned char c) |
407 | { | |
408 | return (c & 0xc0) == 0x80; | |
409 | } | |
410 | ||
411 | /** | |
412 | * is_continuation - multibyte check | |
413 | * @c: byte to check | |
414 | * | |
415 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
416 | * character and the terminal is in unicode mode. | |
417 | */ | |
4edf1827 | 418 | |
1da177e4 LT |
419 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
420 | { | |
421 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
422 | } | |
423 | ||
424 | /** | |
a88a69c9 | 425 | * do_output_char - output one character |
1da177e4 LT |
426 | * @c: character (or partial unicode symbol) |
427 | * @tty: terminal device | |
a88a69c9 | 428 | * @space: space available in tty driver write buffer |
1da177e4 | 429 | * |
a88a69c9 JP |
430 | * This is a helper function that handles one output character |
431 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
432 | * doing OPOST processing and putting the results in the |
433 | * tty driver's write buffer. | |
a88a69c9 JP |
434 | * |
435 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
436 | * and NLDLY. They simply aren't relevant in the world today. | |
437 | * If you ever need them, add them here. | |
1da177e4 | 438 | * |
a88a69c9 JP |
439 | * Returns the number of bytes of buffer space used or -1 if |
440 | * no space left. | |
441 | * | |
442 | * Locking: should be called under the output_lock to protect | |
443 | * the column state and space left in the buffer | |
1da177e4 | 444 | */ |
4edf1827 | 445 | |
a88a69c9 | 446 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 447 | { |
53c5ee2c | 448 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 449 | int spaces; |
1da177e4 | 450 | |
1da177e4 LT |
451 | if (!space) |
452 | return -1; | |
300a6204 | 453 | |
a88a69c9 JP |
454 | switch (c) { |
455 | case '\n': | |
456 | if (O_ONLRET(tty)) | |
53c5ee2c | 457 | ldata->column = 0; |
a88a69c9 JP |
458 | if (O_ONLCR(tty)) { |
459 | if (space < 2) | |
460 | return -1; | |
ba2e68ac | 461 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 462 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
463 | return 2; |
464 | } | |
ba2e68ac | 465 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
466 | break; |
467 | case '\r': | |
53c5ee2c | 468 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
469 | return 0; |
470 | if (O_OCRNL(tty)) { | |
471 | c = '\n'; | |
472 | if (O_ONLRET(tty)) | |
ba2e68ac | 473 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 474 | break; |
a88a69c9 | 475 | } |
ba2e68ac | 476 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
477 | break; |
478 | case '\t': | |
53c5ee2c | 479 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
480 | if (O_TABDLY(tty) == XTABS) { |
481 | if (space < spaces) | |
482 | return -1; | |
53c5ee2c | 483 | ldata->column += spaces; |
a88a69c9 JP |
484 | tty->ops->write(tty, " ", spaces); |
485 | return spaces; | |
1da177e4 | 486 | } |
53c5ee2c | 487 | ldata->column += spaces; |
a88a69c9 JP |
488 | break; |
489 | case '\b': | |
53c5ee2c JS |
490 | if (ldata->column > 0) |
491 | ldata->column--; | |
a88a69c9 JP |
492 | break; |
493 | default: | |
a59c0d6f JP |
494 | if (!iscntrl(c)) { |
495 | if (O_OLCUC(tty)) | |
496 | c = toupper(c); | |
497 | if (!is_continuation(c, tty)) | |
53c5ee2c | 498 | ldata->column++; |
a59c0d6f | 499 | } |
a88a69c9 | 500 | break; |
1da177e4 | 501 | } |
a88a69c9 | 502 | |
f34d7a5b | 503 | tty_put_char(tty, c); |
a88a69c9 JP |
504 | return 1; |
505 | } | |
506 | ||
507 | /** | |
508 | * process_output - output post processor | |
509 | * @c: character (or partial unicode symbol) | |
510 | * @tty: terminal device | |
511 | * | |
ee5aa7b8 JP |
512 | * Output one character with OPOST processing. |
513 | * Returns -1 when the output device is full and the character | |
514 | * must be retried. | |
a88a69c9 JP |
515 | * |
516 | * Locking: output_lock to protect column state and space left | |
517 | * (also, this is called from n_tty_write under the | |
518 | * tty layer write lock) | |
519 | */ | |
520 | ||
521 | static int process_output(unsigned char c, struct tty_struct *tty) | |
522 | { | |
bddc7152 | 523 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
524 | int space, retval; |
525 | ||
bddc7152 | 526 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
527 | |
528 | space = tty_write_room(tty); | |
529 | retval = do_output_char(c, tty, space); | |
530 | ||
bddc7152 | 531 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
532 | if (retval < 0) |
533 | return -1; | |
534 | else | |
535 | return 0; | |
1da177e4 LT |
536 | } |
537 | ||
538 | /** | |
a88a69c9 | 539 | * process_output_block - block post processor |
1da177e4 | 540 | * @tty: terminal device |
ee5aa7b8 JP |
541 | * @buf: character buffer |
542 | * @nr: number of bytes to output | |
543 | * | |
544 | * Output a block of characters with OPOST processing. | |
545 | * Returns the number of characters output. | |
1da177e4 LT |
546 | * |
547 | * This path is used to speed up block console writes, among other | |
548 | * things when processing blocks of output data. It handles only | |
549 | * the simple cases normally found and helps to generate blocks of | |
550 | * symbols for the console driver and thus improve performance. | |
551 | * | |
a88a69c9 JP |
552 | * Locking: output_lock to protect column state and space left |
553 | * (also, this is called from n_tty_write under the | |
554 | * tty layer write lock) | |
1da177e4 | 555 | */ |
4edf1827 | 556 | |
a88a69c9 JP |
557 | static ssize_t process_output_block(struct tty_struct *tty, |
558 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 559 | { |
53c5ee2c | 560 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 561 | int space; |
bbd20759 | 562 | int i; |
1da177e4 LT |
563 | const unsigned char *cp; |
564 | ||
bddc7152 | 565 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 566 | |
f34d7a5b | 567 | space = tty_write_room(tty); |
300a6204 | 568 | if (!space) { |
bddc7152 | 569 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 570 | return 0; |
a88a69c9 | 571 | } |
1da177e4 LT |
572 | if (nr > space) |
573 | nr = space; | |
574 | ||
575 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
576 | unsigned char c = *cp; |
577 | ||
578 | switch (c) { | |
1da177e4 LT |
579 | case '\n': |
580 | if (O_ONLRET(tty)) | |
53c5ee2c | 581 | ldata->column = 0; |
1da177e4 LT |
582 | if (O_ONLCR(tty)) |
583 | goto break_out; | |
ba2e68ac | 584 | ldata->canon_column = ldata->column; |
1da177e4 LT |
585 | break; |
586 | case '\r': | |
53c5ee2c | 587 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
588 | goto break_out; |
589 | if (O_OCRNL(tty)) | |
590 | goto break_out; | |
ba2e68ac | 591 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
592 | break; |
593 | case '\t': | |
594 | goto break_out; | |
595 | case '\b': | |
53c5ee2c JS |
596 | if (ldata->column > 0) |
597 | ldata->column--; | |
1da177e4 LT |
598 | break; |
599 | default: | |
a59c0d6f JP |
600 | if (!iscntrl(c)) { |
601 | if (O_OLCUC(tty)) | |
602 | goto break_out; | |
603 | if (!is_continuation(c, tty)) | |
53c5ee2c | 604 | ldata->column++; |
a59c0d6f | 605 | } |
1da177e4 LT |
606 | break; |
607 | } | |
608 | } | |
609 | break_out: | |
f34d7a5b | 610 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 611 | |
bddc7152 | 612 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
613 | return i; |
614 | } | |
615 | ||
a88a69c9 JP |
616 | /** |
617 | * process_echoes - write pending echo characters | |
618 | * @tty: terminal device | |
619 | * | |
620 | * Write previously buffered echo (and other ldisc-generated) | |
621 | * characters to the tty. | |
622 | * | |
623 | * Characters generated by the ldisc (including echoes) need to | |
624 | * be buffered because the driver's write buffer can fill during | |
625 | * heavy program output. Echoing straight to the driver will | |
626 | * often fail under these conditions, causing lost characters and | |
627 | * resulting mismatches of ldisc state information. | |
628 | * | |
629 | * Since the ldisc state must represent the characters actually sent | |
630 | * to the driver at the time of the write, operations like certain | |
631 | * changes in column state are also saved in the buffer and executed | |
632 | * here. | |
633 | * | |
634 | * A circular fifo buffer is used so that the most recent characters | |
635 | * are prioritized. Also, when control characters are echoed with a | |
636 | * prefixed "^", the pair is treated atomically and thus not separated. | |
637 | * | |
019ebdf9 | 638 | * Locking: callers must hold output_lock |
a88a69c9 JP |
639 | */ |
640 | ||
bc5b1ec5 | 641 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 642 | { |
53c5ee2c | 643 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 644 | int space, old_space; |
addaebcc | 645 | size_t tail; |
a88a69c9 | 646 | unsigned char c; |
a88a69c9 | 647 | |
bc5b1ec5 | 648 | old_space = space = tty_write_room(tty); |
a88a69c9 | 649 | |
addaebcc | 650 | tail = ldata->echo_tail; |
29c7c5ca | 651 | while (ldata->echo_commit != tail) { |
addaebcc | 652 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
653 | if (c == ECHO_OP_START) { |
654 | unsigned char op; | |
a88a69c9 JP |
655 | int no_space_left = 0; |
656 | ||
657 | /* | |
658 | * If the buffer byte is the start of a multi-byte | |
659 | * operation, get the next byte, which is either the | |
660 | * op code or a control character value. | |
661 | */ | |
addaebcc | 662 | op = echo_buf(ldata, tail + 1); |
300a6204 | 663 | |
a88a69c9 JP |
664 | switch (op) { |
665 | unsigned int num_chars, num_bs; | |
666 | ||
667 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 668 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
669 | |
670 | /* | |
671 | * Determine how many columns to go back | |
672 | * in order to erase the tab. | |
673 | * This depends on the number of columns | |
674 | * used by other characters within the tab | |
675 | * area. If this (modulo 8) count is from | |
676 | * the start of input rather than from a | |
677 | * previous tab, we offset by canon column. | |
678 | * Otherwise, tab spacing is normal. | |
679 | */ | |
680 | if (!(num_chars & 0x80)) | |
ba2e68ac | 681 | num_chars += ldata->canon_column; |
a88a69c9 JP |
682 | num_bs = 8 - (num_chars & 7); |
683 | ||
684 | if (num_bs > space) { | |
685 | no_space_left = 1; | |
686 | break; | |
687 | } | |
688 | space -= num_bs; | |
689 | while (num_bs--) { | |
690 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
691 | if (ldata->column > 0) |
692 | ldata->column--; | |
a88a69c9 | 693 | } |
addaebcc | 694 | tail += 3; |
a88a69c9 JP |
695 | break; |
696 | ||
697 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 698 | ldata->canon_column = ldata->column; |
addaebcc | 699 | tail += 2; |
a88a69c9 JP |
700 | break; |
701 | ||
702 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
703 | if (ldata->column > 0) |
704 | ldata->column--; | |
addaebcc | 705 | tail += 2; |
a88a69c9 JP |
706 | break; |
707 | ||
708 | case ECHO_OP_START: | |
709 | /* This is an escaped echo op start code */ | |
710 | if (!space) { | |
711 | no_space_left = 1; | |
712 | break; | |
713 | } | |
714 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 715 | ldata->column++; |
a88a69c9 | 716 | space--; |
addaebcc | 717 | tail += 2; |
a88a69c9 JP |
718 | break; |
719 | ||
720 | default: | |
a88a69c9 | 721 | /* |
62b26358 JP |
722 | * If the op is not a special byte code, |
723 | * it is a ctrl char tagged to be echoed | |
724 | * as "^X" (where X is the letter | |
725 | * representing the control char). | |
726 | * Note that we must ensure there is | |
727 | * enough space for the whole ctrl pair. | |
728 | * | |
a88a69c9 | 729 | */ |
62b26358 JP |
730 | if (space < 2) { |
731 | no_space_left = 1; | |
732 | break; | |
733 | } | |
734 | tty_put_char(tty, '^'); | |
735 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 736 | ldata->column += 2; |
62b26358 | 737 | space -= 2; |
addaebcc | 738 | tail += 2; |
a88a69c9 JP |
739 | } |
740 | ||
741 | if (no_space_left) | |
742 | break; | |
743 | } else { | |
582f5590 | 744 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
745 | int retval = do_output_char(c, tty, space); |
746 | if (retval < 0) | |
747 | break; | |
748 | space -= retval; | |
749 | } else { | |
750 | if (!space) | |
751 | break; | |
752 | tty_put_char(tty, c); | |
753 | space -= 1; | |
754 | } | |
addaebcc | 755 | tail += 1; |
a88a69c9 | 756 | } |
a88a69c9 JP |
757 | } |
758 | ||
cbfd0340 PH |
759 | /* If the echo buffer is nearly full (so that the possibility exists |
760 | * of echo overrun before the next commit), then discard enough | |
761 | * data at the tail to prevent a subsequent overrun */ | |
762 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 763 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 764 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
765 | tail += 3; |
766 | else | |
767 | tail += 2; | |
768 | } else | |
769 | tail++; | |
770 | } | |
771 | ||
addaebcc | 772 | ldata->echo_tail = tail; |
bc5b1ec5 | 773 | return old_space - space; |
019ebdf9 PH |
774 | } |
775 | ||
776 | static void commit_echoes(struct tty_struct *tty) | |
777 | { | |
778 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 779 | size_t nr, old, echoed; |
cbfd0340 PH |
780 | size_t head; |
781 | ||
782 | head = ldata->echo_head; | |
1075a6e2 | 783 | ldata->echo_mark = head; |
cbfd0340 PH |
784 | old = ldata->echo_commit - ldata->echo_tail; |
785 | ||
786 | /* Process committed echoes if the accumulated # of bytes | |
787 | * is over the threshold (and try again each time another | |
788 | * block is accumulated) */ | |
789 | nr = head - ldata->echo_tail; | |
790 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
791 | return; | |
a88a69c9 | 792 | |
019ebdf9 | 793 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 794 | ldata->echo_commit = head; |
bc5b1ec5 | 795 | echoed = __process_echoes(tty); |
bddc7152 | 796 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 797 | |
bc5b1ec5 | 798 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
799 | tty->ops->flush_chars(tty); |
800 | } | |
801 | ||
019ebdf9 | 802 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
803 | { |
804 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 805 | size_t echoed; |
17bd7907 | 806 | |
e2613be5 | 807 | if (ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
808 | return; |
809 | ||
810 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 811 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 812 | echoed = __process_echoes(tty); |
019ebdf9 PH |
813 | mutex_unlock(&ldata->output_lock); |
814 | ||
bc5b1ec5 | 815 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 816 | tty->ops->flush_chars(tty); |
17bd7907 PH |
817 | } |
818 | ||
1075a6e2 | 819 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
820 | static void flush_echoes(struct tty_struct *tty) |
821 | { | |
822 | struct n_tty_data *ldata = tty->disc_data; | |
823 | ||
39434abd PH |
824 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
825 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
826 | return; |
827 | ||
828 | mutex_lock(&ldata->output_lock); | |
829 | ldata->echo_commit = ldata->echo_head; | |
830 | __process_echoes(tty); | |
831 | mutex_unlock(&ldata->output_lock); | |
832 | } | |
833 | ||
a88a69c9 JP |
834 | /** |
835 | * add_echo_byte - add a byte to the echo buffer | |
836 | * @c: unicode byte to echo | |
57c94121 | 837 | * @ldata: n_tty data |
a88a69c9 JP |
838 | * |
839 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
840 | */ |
841 | ||
cbfd0340 | 842 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 843 | { |
addaebcc | 844 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
845 | } |
846 | ||
847 | /** | |
848 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 849 | * @ldata: n_tty data |
a88a69c9 JP |
850 | * |
851 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
852 | */ |
853 | ||
57c94121 | 854 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 855 | { |
57c94121 JS |
856 | add_echo_byte(ECHO_OP_START, ldata); |
857 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
858 | } |
859 | ||
860 | /** | |
861 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 862 | * @ldata: n_tty data |
a88a69c9 JP |
863 | * |
864 | * Add an operation to the echo buffer to set the canon column | |
865 | * to the current column. | |
a88a69c9 JP |
866 | */ |
867 | ||
57c94121 | 868 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 869 | { |
57c94121 JS |
870 | add_echo_byte(ECHO_OP_START, ldata); |
871 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
872 | } |
873 | ||
874 | /** | |
875 | * echo_erase_tab - add operation to erase a tab | |
876 | * @num_chars: number of character columns already used | |
877 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 878 | * @ldata: n_tty data |
a88a69c9 JP |
879 | * |
880 | * Add an operation to the echo buffer to erase a tab. | |
881 | * | |
882 | * Called by the eraser function, which knows how many character | |
883 | * columns have been used since either a previous tab or the start | |
884 | * of input. This information will be used later, along with | |
885 | * canon column (if applicable), to go back the correct number | |
886 | * of columns. | |
a88a69c9 JP |
887 | */ |
888 | ||
889 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 890 | struct n_tty_data *ldata) |
a88a69c9 | 891 | { |
57c94121 JS |
892 | add_echo_byte(ECHO_OP_START, ldata); |
893 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
894 | |
895 | /* We only need to know this modulo 8 (tab spacing) */ | |
896 | num_chars &= 7; | |
897 | ||
898 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
899 | if (after_tab) | |
900 | num_chars |= 0x80; | |
300a6204 | 901 | |
57c94121 | 902 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
903 | } |
904 | ||
905 | /** | |
906 | * echo_char_raw - echo a character raw | |
907 | * @c: unicode byte to echo | |
908 | * @tty: terminal device | |
909 | * | |
910 | * Echo user input back onto the screen. This must be called only when | |
911 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
912 | * | |
913 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
914 | */ |
915 | ||
57c94121 | 916 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 917 | { |
a88a69c9 | 918 | if (c == ECHO_OP_START) { |
57c94121 JS |
919 | add_echo_byte(ECHO_OP_START, ldata); |
920 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 921 | } else { |
57c94121 | 922 | add_echo_byte(c, ldata); |
a88a69c9 | 923 | } |
a88a69c9 | 924 | } |
1da177e4 | 925 | |
1da177e4 | 926 | /** |
a88a69c9 | 927 | * echo_char - echo a character |
1da177e4 LT |
928 | * @c: unicode byte to echo |
929 | * @tty: terminal device | |
930 | * | |
4edf1827 | 931 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 932 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 933 | * |
62b26358 JP |
934 | * This variant tags control characters to be echoed as "^X" |
935 | * (where X is the letter representing the control char). | |
1da177e4 LT |
936 | */ |
937 | ||
938 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
939 | { | |
bddc7152 JS |
940 | struct n_tty_data *ldata = tty->disc_data; |
941 | ||
a88a69c9 | 942 | if (c == ECHO_OP_START) { |
57c94121 JS |
943 | add_echo_byte(ECHO_OP_START, ldata); |
944 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 945 | } else { |
62b26358 | 946 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
947 | add_echo_byte(ECHO_OP_START, ldata); |
948 | add_echo_byte(c, ldata); | |
a88a69c9 | 949 | } |
1da177e4 LT |
950 | } |
951 | ||
17b82060 | 952 | /** |
a88a69c9 | 953 | * finish_erasing - complete erase |
57c94121 | 954 | * @ldata: n_tty data |
17b82060 | 955 | */ |
a88a69c9 | 956 | |
57c94121 | 957 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 958 | { |
53c5ee2c | 959 | if (ldata->erasing) { |
57c94121 | 960 | echo_char_raw('/', ldata); |
53c5ee2c | 961 | ldata->erasing = 0; |
1da177e4 LT |
962 | } |
963 | } | |
964 | ||
965 | /** | |
966 | * eraser - handle erase function | |
967 | * @c: character input | |
968 | * @tty: terminal device | |
969 | * | |
3a4fa0a2 | 970 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
971 | * present in the stream from the driver layer. Handles the complexities |
972 | * of UTF-8 multibyte symbols. | |
17b82060 | 973 | * |
6d76bd26 PH |
974 | * n_tty_receive_buf()/producer path: |
975 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 976 | */ |
4edf1827 | 977 | |
1da177e4 LT |
978 | static void eraser(unsigned char c, struct tty_struct *tty) |
979 | { | |
53c5ee2c | 980 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 981 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
982 | size_t head; |
983 | size_t cnt; | |
984 | int seen_alnums; | |
1da177e4 | 985 | |
ba2e68ac | 986 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 987 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
988 | return; |
989 | } | |
990 | if (c == ERASE_CHAR(tty)) | |
991 | kill_type = ERASE; | |
992 | else if (c == WERASE_CHAR(tty)) | |
993 | kill_type = WERASE; | |
994 | else { | |
995 | if (!L_ECHO(tty)) { | |
ba2e68ac | 996 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
997 | return; |
998 | } | |
999 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 1000 | ldata->read_head = ldata->canon_head; |
57c94121 | 1001 | finish_erasing(ldata); |
1da177e4 LT |
1002 | echo_char(KILL_CHAR(tty), tty); |
1003 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
1004 | if (L_ECHOK(tty)) | |
57c94121 | 1005 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1006 | return; |
1007 | } | |
1008 | kill_type = KILL; | |
1009 | } | |
1010 | ||
1011 | seen_alnums = 0; | |
ba2e68ac JS |
1012 | while (ldata->read_head != ldata->canon_head) { |
1013 | head = ldata->read_head; | |
1da177e4 LT |
1014 | |
1015 | /* erase a single possibly multibyte character */ | |
1016 | do { | |
bc5a5e3f PH |
1017 | head--; |
1018 | c = read_buf(ldata, head); | |
ba2e68ac | 1019 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1020 | |
1021 | /* do not partially erase */ | |
1022 | if (is_continuation(c, tty)) | |
1023 | break; | |
1024 | ||
1025 | if (kill_type == WERASE) { | |
1026 | /* Equivalent to BSD's ALTWERASE. */ | |
1027 | if (isalnum(c) || c == '_') | |
1028 | seen_alnums++; | |
1029 | else if (seen_alnums) | |
1030 | break; | |
1031 | } | |
bc5a5e3f | 1032 | cnt = ldata->read_head - head; |
ba2e68ac | 1033 | ldata->read_head = head; |
1da177e4 LT |
1034 | if (L_ECHO(tty)) { |
1035 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1036 | if (!ldata->erasing) { |
57c94121 | 1037 | echo_char_raw('\\', ldata); |
53c5ee2c | 1038 | ldata->erasing = 1; |
1da177e4 LT |
1039 | } |
1040 | /* if cnt > 1, output a multi-byte character */ | |
1041 | echo_char(c, tty); | |
1042 | while (--cnt > 0) { | |
bc5a5e3f PH |
1043 | head++; |
1044 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1045 | echo_move_back_col(ldata); |
1da177e4 LT |
1046 | } |
1047 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1048 | echo_char(ERASE_CHAR(tty), tty); | |
1049 | } else if (c == '\t') { | |
a88a69c9 JP |
1050 | unsigned int num_chars = 0; |
1051 | int after_tab = 0; | |
bc5a5e3f | 1052 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1053 | |
1054 | /* | |
1055 | * Count the columns used for characters | |
1056 | * since the start of input or after a | |
1057 | * previous tab. | |
1058 | * This info is used to go back the correct | |
1059 | * number of columns. | |
1060 | */ | |
ba2e68ac | 1061 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1062 | tail--; |
1063 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1064 | if (c == '\t') { |
1065 | after_tab = 1; | |
1066 | break; | |
300a6204 | 1067 | } else if (iscntrl(c)) { |
1da177e4 | 1068 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1069 | num_chars += 2; |
1070 | } else if (!is_continuation(c, tty)) { | |
1071 | num_chars++; | |
1072 | } | |
1da177e4 | 1073 | } |
57c94121 | 1074 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1075 | } else { |
1076 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1077 | echo_char_raw('\b', ldata); |
1078 | echo_char_raw(' ', ldata); | |
1079 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1080 | } |
1081 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1082 | echo_char_raw('\b', ldata); |
1083 | echo_char_raw(' ', ldata); | |
1084 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1085 | } |
1086 | } | |
1087 | } | |
1088 | if (kill_type == ERASE) | |
1089 | break; | |
1090 | } | |
ba2e68ac | 1091 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1092 | finish_erasing(ldata); |
1da177e4 LT |
1093 | } |
1094 | ||
1095 | /** | |
1096 | * isig - handle the ISIG optio | |
1097 | * @sig: signal | |
1098 | * @tty: terminal | |
1da177e4 | 1099 | * |
8c985d18 PH |
1100 | * Called when a signal is being sent due to terminal input. |
1101 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1102 | * |
d2b6f447 PH |
1103 | * Performs input and output flush if !NOFLSH. In this context, the echo |
1104 | * buffer is 'output'. The signal is processed first to alert any current | |
1105 | * readers or writers to discontinue and exit their i/o loops. | |
1106 | * | |
8c985d18 | 1107 | * Locking: ctrl_lock |
1da177e4 | 1108 | */ |
4edf1827 | 1109 | |
3b19e032 | 1110 | static void __isig(int sig, struct tty_struct *tty) |
1da177e4 | 1111 | { |
8c985d18 PH |
1112 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1113 | if (tty_pgrp) { | |
1114 | kill_pgrp(tty_pgrp, sig, 1); | |
1115 | put_pid(tty_pgrp); | |
1da177e4 | 1116 | } |
3b19e032 | 1117 | } |
d2b6f447 | 1118 | |
3b19e032 PH |
1119 | static void isig(int sig, struct tty_struct *tty) |
1120 | { | |
1121 | struct n_tty_data *ldata = tty->disc_data; | |
1122 | ||
1123 | if (L_NOFLSH(tty)) { | |
1124 | /* signal only */ | |
1125 | __isig(sig, tty); | |
1126 | ||
1127 | } else { /* signal and flush */ | |
d2b6f447 PH |
1128 | up_read(&tty->termios_rwsem); |
1129 | down_write(&tty->termios_rwsem); | |
1130 | ||
3b19e032 PH |
1131 | __isig(sig, tty); |
1132 | ||
d2b6f447 PH |
1133 | /* clear echo buffer */ |
1134 | mutex_lock(&ldata->output_lock); | |
1135 | ldata->echo_head = ldata->echo_tail = 0; | |
1136 | ldata->echo_mark = ldata->echo_commit = 0; | |
1137 | mutex_unlock(&ldata->output_lock); | |
1138 | ||
1139 | /* clear output buffer */ | |
1140 | tty_driver_flush_buffer(tty); | |
1141 | ||
1142 | /* clear input buffer */ | |
1143 | reset_buffer_flags(tty->disc_data); | |
1144 | ||
1145 | /* notify pty master of flush */ | |
1146 | if (tty->link) | |
1147 | n_tty_packet_mode_flush(tty); | |
1148 | ||
1149 | up_write(&tty->termios_rwsem); | |
1150 | down_read(&tty->termios_rwsem); | |
1151 | } | |
1da177e4 LT |
1152 | } |
1153 | ||
1154 | /** | |
1155 | * n_tty_receive_break - handle break | |
1156 | * @tty: terminal | |
1157 | * | |
1158 | * An RS232 break event has been hit in the incoming bitstream. This | |
1159 | * can cause a variety of events depending upon the termios settings. | |
1160 | * | |
6d76bd26 PH |
1161 | * n_tty_receive_buf()/producer path: |
1162 | * caller holds non-exclusive termios_rwsem | |
6d76bd26 PH |
1163 | * |
1164 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1165 | */ |
4edf1827 | 1166 | |
4b293492 | 1167 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1168 | { |
57c94121 JS |
1169 | struct n_tty_data *ldata = tty->disc_data; |
1170 | ||
1da177e4 LT |
1171 | if (I_IGNBRK(tty)) |
1172 | return; | |
1173 | if (I_BRKINT(tty)) { | |
8c985d18 | 1174 | isig(SIGINT, tty); |
1da177e4 LT |
1175 | return; |
1176 | } | |
1177 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1178 | put_tty_queue('\377', ldata); |
1179 | put_tty_queue('\0', ldata); | |
1da177e4 | 1180 | } |
57c94121 | 1181 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1182 | } |
1183 | ||
1184 | /** | |
1185 | * n_tty_receive_overrun - handle overrun reporting | |
1186 | * @tty: terminal | |
1187 | * | |
1188 | * Data arrived faster than we could process it. While the tty | |
1189 | * driver has flagged this the bits that were missed are gone | |
1190 | * forever. | |
1191 | * | |
1192 | * Called from the receive_buf path so single threaded. Does not | |
1193 | * need locking as num_overrun and overrun_time are function | |
1194 | * private. | |
1195 | */ | |
4edf1827 | 1196 | |
4b293492 | 1197 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1198 | { |
53c5ee2c | 1199 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1200 | |
53c5ee2c JS |
1201 | ldata->num_overrun++; |
1202 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1203 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 | 1204 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
429b4749 | 1205 | tty_name(tty), |
53c5ee2c JS |
1206 | ldata->num_overrun); |
1207 | ldata->overrun_time = jiffies; | |
1208 | ldata->num_overrun = 0; | |
1da177e4 LT |
1209 | } |
1210 | } | |
1211 | ||
1212 | /** | |
1213 | * n_tty_receive_parity_error - error notifier | |
1214 | * @tty: terminal device | |
1215 | * @c: character | |
1216 | * | |
1217 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1218 | * the error case if necessary. |
1219 | * | |
1220 | * n_tty_receive_buf()/producer path: | |
1221 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 1222 | */ |
4b293492 | 1223 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1224 | { |
57c94121 JS |
1225 | struct n_tty_data *ldata = tty->disc_data; |
1226 | ||
66528f90 PH |
1227 | if (I_INPCK(tty)) { |
1228 | if (I_IGNPAR(tty)) | |
1229 | return; | |
1230 | if (I_PARMRK(tty)) { | |
1231 | put_tty_queue('\377', ldata); | |
1232 | put_tty_queue('\0', ldata); | |
1233 | put_tty_queue(c, ldata); | |
1234 | } else | |
1235 | put_tty_queue('\0', ldata); | |
1236 | } else | |
57c94121 | 1237 | put_tty_queue(c, ldata); |
1da177e4 LT |
1238 | } |
1239 | ||
b0ac50be PH |
1240 | static void |
1241 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1242 | { | |
d2b6f447 | 1243 | isig(signal, tty); |
b0ac50be PH |
1244 | if (I_IXON(tty)) |
1245 | start_tty(tty); | |
1246 | if (L_ECHO(tty)) { | |
1247 | echo_char(c, tty); | |
1248 | commit_echoes(tty); | |
e2613be5 PH |
1249 | } else |
1250 | process_echoes(tty); | |
b0ac50be PH |
1251 | return; |
1252 | } | |
1253 | ||
1da177e4 LT |
1254 | /** |
1255 | * n_tty_receive_char - perform processing | |
1256 | * @tty: terminal device | |
1257 | * @c: character | |
1258 | * | |
1259 | * Process an individual character of input received from the driver. | |
4edf1827 | 1260 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1261 | * driver above. |
6d76bd26 PH |
1262 | * |
1263 | * n_tty_receive_buf()/producer path: | |
1264 | * caller holds non-exclusive termios_rwsem | |
1265 | * publishes canon_head if canonical mode is active | |
e60d27c4 PH |
1266 | * |
1267 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1268 | */ |
1269 | ||
e60d27c4 | 1270 | static int |
4b1f79c2 | 1271 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1272 | { |
53c5ee2c | 1273 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1274 | |
1da177e4 LT |
1275 | if (I_IXON(tty)) { |
1276 | if (c == START_CHAR(tty)) { | |
1277 | start_tty(tty); | |
e2613be5 | 1278 | process_echoes(tty); |
e60d27c4 | 1279 | return 0; |
1da177e4 LT |
1280 | } |
1281 | if (c == STOP_CHAR(tty)) { | |
1282 | stop_tty(tty); | |
e60d27c4 | 1283 | return 0; |
1da177e4 LT |
1284 | } |
1285 | } | |
575537b3 | 1286 | |
1da177e4 | 1287 | if (L_ISIG(tty)) { |
b0ac50be PH |
1288 | if (c == INTR_CHAR(tty)) { |
1289 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1290 | return 0; |
b0ac50be PH |
1291 | } else if (c == QUIT_CHAR(tty)) { |
1292 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1293 | return 0; |
b0ac50be PH |
1294 | } else if (c == SUSP_CHAR(tty)) { |
1295 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1296 | return 0; |
1da177e4 LT |
1297 | } |
1298 | } | |
575537b3 | 1299 | |
855df3c0 PH |
1300 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1301 | start_tty(tty); | |
1302 | process_echoes(tty); | |
1303 | } | |
1304 | ||
575537b3 JP |
1305 | if (c == '\r') { |
1306 | if (I_IGNCR(tty)) | |
e60d27c4 | 1307 | return 0; |
575537b3 JP |
1308 | if (I_ICRNL(tty)) |
1309 | c = '\n'; | |
1310 | } else if (c == '\n' && I_INLCR(tty)) | |
1311 | c = '\r'; | |
1312 | ||
53c5ee2c | 1313 | if (ldata->icanon) { |
1da177e4 LT |
1314 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1315 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1316 | eraser(c, tty); | |
17bd7907 | 1317 | commit_echoes(tty); |
e60d27c4 | 1318 | return 0; |
1da177e4 LT |
1319 | } |
1320 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1321 | ldata->lnext = 1; |
1da177e4 | 1322 | if (L_ECHO(tty)) { |
57c94121 | 1323 | finish_erasing(ldata); |
1da177e4 | 1324 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1325 | echo_char_raw('^', ldata); |
1326 | echo_char_raw('\b', ldata); | |
17bd7907 | 1327 | commit_echoes(tty); |
1da177e4 LT |
1328 | } |
1329 | } | |
e60d27c4 | 1330 | return 1; |
1da177e4 | 1331 | } |
e60d27c4 | 1332 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1333 | size_t tail = ldata->canon_head; |
1da177e4 | 1334 | |
57c94121 | 1335 | finish_erasing(ldata); |
1da177e4 | 1336 | echo_char(c, tty); |
57c94121 | 1337 | echo_char_raw('\n', ldata); |
ba2e68ac | 1338 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1339 | echo_char(read_buf(ldata, tail), tty); |
1340 | tail++; | |
1da177e4 | 1341 | } |
17bd7907 | 1342 | commit_echoes(tty); |
e60d27c4 | 1343 | return 0; |
1da177e4 LT |
1344 | } |
1345 | if (c == '\n') { | |
acc71bba | 1346 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1347 | echo_char_raw('\n', ldata); |
17bd7907 | 1348 | commit_echoes(tty); |
1da177e4 LT |
1349 | } |
1350 | goto handle_newline; | |
1351 | } | |
1352 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1353 | c = __DISABLED_CHAR; |
1354 | goto handle_newline; | |
1355 | } | |
1356 | if ((c == EOL_CHAR(tty)) || | |
1357 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1358 | /* | |
1359 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1360 | */ | |
1361 | if (L_ECHO(tty)) { | |
1da177e4 | 1362 | /* Record the column of first canon char. */ |
ba2e68ac | 1363 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1364 | echo_set_canon_col(ldata); |
1da177e4 | 1365 | echo_char(c, tty); |
17bd7907 | 1366 | commit_echoes(tty); |
1da177e4 LT |
1367 | } |
1368 | /* | |
1369 | * XXX does PARMRK doubling happen for | |
1370 | * EOL_CHAR and EOL2_CHAR? | |
1371 | */ | |
001ba923 | 1372 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
57c94121 | 1373 | put_tty_queue(c, ldata); |
1da177e4 | 1374 | |
4edf1827 | 1375 | handle_newline: |
bc5a5e3f | 1376 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1377 | put_tty_queue(c, ldata); |
70aca71f | 1378 | smp_store_release(&ldata->canon_head, ldata->read_head); |
1da177e4 | 1379 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
e81107d4 | 1380 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
e60d27c4 | 1381 | return 0; |
1da177e4 LT |
1382 | } |
1383 | } | |
4edf1827 | 1384 | |
acc71bba | 1385 | if (L_ECHO(tty)) { |
57c94121 | 1386 | finish_erasing(ldata); |
1da177e4 | 1387 | if (c == '\n') |
57c94121 | 1388 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1389 | else { |
1390 | /* Record the column of first canon char. */ | |
ba2e68ac | 1391 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1392 | echo_set_canon_col(ldata); |
1da177e4 LT |
1393 | echo_char(c, tty); |
1394 | } | |
17bd7907 | 1395 | commit_echoes(tty); |
1da177e4 LT |
1396 | } |
1397 | ||
001ba923 PH |
1398 | /* PARMRK doubling check */ |
1399 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
57c94121 | 1400 | put_tty_queue(c, ldata); |
1da177e4 | 1401 | |
57c94121 | 1402 | put_tty_queue(c, ldata); |
e60d27c4 | 1403 | return 0; |
4edf1827 | 1404 | } |
1da177e4 | 1405 | |
e60d27c4 PH |
1406 | static inline void |
1407 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1408 | { |
1409 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1410 | |
e60d27c4 PH |
1411 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1412 | start_tty(tty); | |
1413 | process_echoes(tty); | |
1414 | } | |
1415 | if (L_ECHO(tty)) { | |
1416 | finish_erasing(ldata); | |
1417 | /* Record the column of first canon char. */ | |
1418 | if (ldata->canon_head == ldata->read_head) | |
1419 | echo_set_canon_col(ldata); | |
1420 | echo_char(c, tty); | |
1421 | commit_echoes(tty); | |
4b1f79c2 | 1422 | } |
001ba923 PH |
1423 | /* PARMRK doubling check */ |
1424 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
e60d27c4 PH |
1425 | put_tty_queue(c, ldata); |
1426 | put_tty_queue(c, ldata); | |
1427 | } | |
4b1f79c2 | 1428 | |
eb3e4668 | 1429 | static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
e60d27c4 PH |
1430 | { |
1431 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1432 | } |
1433 | ||
7de971b0 PH |
1434 | static inline void |
1435 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1436 | { | |
1437 | struct n_tty_data *ldata = tty->disc_data; | |
1438 | ||
e60d27c4 PH |
1439 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1440 | start_tty(tty); | |
1441 | process_echoes(tty); | |
7de971b0 | 1442 | } |
e60d27c4 PH |
1443 | if (L_ECHO(tty)) { |
1444 | finish_erasing(ldata); | |
1445 | /* Record the column of first canon char. */ | |
1446 | if (ldata->canon_head == ldata->read_head) | |
1447 | echo_set_canon_col(ldata); | |
1448 | echo_char(c, tty); | |
1449 | commit_echoes(tty); | |
1450 | } | |
1451 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1452 | } |
1453 | ||
8dc4b25d | 1454 | static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) |
ad0cc7ba PH |
1455 | { |
1456 | if (I_ISTRIP(tty)) | |
1457 | c &= 0x7f; | |
1458 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1459 | c = tolower(c); | |
1460 | ||
1461 | if (I_IXON(tty)) { | |
1462 | if (c == STOP_CHAR(tty)) | |
1463 | stop_tty(tty); | |
1464 | else if (c == START_CHAR(tty) || | |
1465 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1466 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1467 | c != SUSP_CHAR(tty))) { | |
1468 | start_tty(tty); | |
1469 | process_echoes(tty); | |
1470 | } | |
1471 | } | |
1472 | } | |
1473 | ||
d2f8d7ab PH |
1474 | static void |
1475 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1476 | { | |
d2f8d7ab PH |
1477 | switch (flag) { |
1478 | case TTY_BREAK: | |
1479 | n_tty_receive_break(tty); | |
1480 | break; | |
1481 | case TTY_PARITY: | |
1482 | case TTY_FRAME: | |
1483 | n_tty_receive_parity_error(tty, c); | |
1484 | break; | |
1485 | case TTY_OVERRUN: | |
1486 | n_tty_receive_overrun(tty); | |
1487 | break; | |
1488 | default: | |
1489 | printk(KERN_ERR "%s: unknown flag %d\n", | |
429b4749 | 1490 | tty_name(tty), flag); |
d2f8d7ab PH |
1491 | break; |
1492 | } | |
1493 | } | |
1494 | ||
e60d27c4 PH |
1495 | static void |
1496 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1497 | { | |
1498 | struct n_tty_data *ldata = tty->disc_data; | |
1499 | ||
1500 | ldata->lnext = 0; | |
1501 | if (likely(flag == TTY_NORMAL)) { | |
1502 | if (I_ISTRIP(tty)) | |
1503 | c &= 0x7f; | |
1504 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1505 | c = tolower(c); | |
1506 | n_tty_receive_char(tty, c); | |
1507 | } else | |
1508 | n_tty_receive_char_flagged(tty, c, flag); | |
1509 | } | |
1510 | ||
4a23a4df PH |
1511 | static void |
1512 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1513 | char *fp, int count) | |
1514 | { | |
1515 | struct n_tty_data *ldata = tty->disc_data; | |
1516 | size_t n, head; | |
1517 | ||
1518 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1519 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1520 | memcpy(read_buf_addr(ldata, head), cp, n); |
1521 | ldata->read_head += n; | |
1522 | cp += n; | |
1523 | count -= n; | |
1524 | ||
1525 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1526 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1527 | memcpy(read_buf_addr(ldata, head), cp, n); |
1528 | ldata->read_head += n; | |
1529 | } | |
1530 | ||
554117bd PH |
1531 | static void |
1532 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1533 | char *fp, int count) | |
1534 | { | |
1535 | struct n_tty_data *ldata = tty->disc_data; | |
1536 | char flag = TTY_NORMAL; | |
1537 | ||
1538 | while (count--) { | |
1539 | if (fp) | |
1540 | flag = *fp++; | |
1541 | if (likely(flag == TTY_NORMAL)) | |
1542 | put_tty_queue(*cp++, ldata); | |
1543 | else | |
1544 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1545 | } | |
1546 | } | |
1547 | ||
ad0cc7ba PH |
1548 | static void |
1549 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1550 | char *fp, int count) | |
1551 | { | |
1552 | char flag = TTY_NORMAL; | |
1553 | ||
1554 | while (count--) { | |
1555 | if (fp) | |
1556 | flag = *fp++; | |
1557 | if (likely(flag == TTY_NORMAL)) | |
1558 | n_tty_receive_char_closing(tty, *cp++); | |
1559 | else | |
1560 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1561 | } | |
1562 | } | |
1563 | ||
7d88d637 PH |
1564 | static void |
1565 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1566 | char *fp, int count) |
1567 | { | |
1568 | struct n_tty_data *ldata = tty->disc_data; | |
1569 | char flag = TTY_NORMAL; | |
1570 | ||
1571 | while (count--) { | |
1572 | if (fp) | |
1573 | flag = *fp++; | |
1574 | if (likely(flag == TTY_NORMAL)) { | |
1575 | unsigned char c = *cp++; | |
1576 | ||
1577 | if (I_ISTRIP(tty)) | |
1578 | c &= 0x7f; | |
1579 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1580 | c = tolower(c); | |
1581 | if (L_EXTPROC(tty)) { | |
1582 | put_tty_queue(c, ldata); | |
1583 | continue; | |
1584 | } | |
e60d27c4 PH |
1585 | if (!test_bit(c, ldata->char_map)) |
1586 | n_tty_receive_char_inline(tty, c); | |
1587 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1588 | if (fp) | |
1589 | flag = *fp++; | |
1590 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1591 | count--; | |
1592 | } | |
6baad008 PH |
1593 | } else |
1594 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1595 | } | |
1596 | } | |
1597 | ||
1598 | static void | |
1599 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1600 | char *fp, int count) | |
7d88d637 | 1601 | { |
e60d27c4 | 1602 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1603 | char flag = TTY_NORMAL; |
1604 | ||
1605 | while (count--) { | |
1606 | if (fp) | |
1607 | flag = *fp++; | |
e60d27c4 PH |
1608 | if (likely(flag == TTY_NORMAL)) { |
1609 | unsigned char c = *cp++; | |
1610 | ||
1611 | if (!test_bit(c, ldata->char_map)) | |
1612 | n_tty_receive_char_fast(tty, c); | |
1613 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1614 | if (fp) | |
1615 | flag = *fp++; | |
1616 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1617 | count--; | |
1618 | } | |
1619 | } else | |
7d88d637 PH |
1620 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1621 | } | |
1622 | } | |
1623 | ||
24a89d1c PH |
1624 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1625 | char *fp, int count) | |
1da177e4 | 1626 | { |
53c5ee2c | 1627 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1628 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1629 | |
4a23a4df PH |
1630 | if (ldata->real_raw) |
1631 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1632 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1633 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1634 | else if (tty->closing && !L_EXTPROC(tty)) |
1635 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1636 | else { |
e60d27c4 PH |
1637 | if (ldata->lnext) { |
1638 | char flag = TTY_NORMAL; | |
1639 | ||
1640 | if (fp) | |
1641 | flag = *fp++; | |
1642 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1643 | count--; | |
1644 | } | |
1645 | ||
7de971b0 | 1646 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1647 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1648 | else | |
1649 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1650 | |
1651 | flush_echoes(tty); | |
f34d7a5b AC |
1652 | if (tty->ops->flush_chars) |
1653 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1654 | } |
1655 | ||
70aca71f PH |
1656 | if (ldata->icanon && !L_EXTPROC(tty)) |
1657 | return; | |
1658 | ||
1659 | /* publish read_head to consumer */ | |
1660 | smp_store_release(&ldata->commit_head, ldata->read_head); | |
1661 | ||
1662 | if ((read_cnt(ldata) >= ldata->minimum_to_wake) || L_EXTPROC(tty)) { | |
1da177e4 | 1663 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
e81107d4 | 1664 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 | 1665 | } |
1da177e4 LT |
1666 | } |
1667 | ||
fb5ef9e7 PH |
1668 | /** |
1669 | * n_tty_receive_buf_common - process input | |
1670 | * @tty: device to receive input | |
1671 | * @cp: input chars | |
1672 | * @fp: flags for each char (if NULL, all chars are TTY_NORMAL) | |
1673 | * @count: number of input chars in @cp | |
1674 | * | |
1675 | * Called by the terminal driver when a block of characters has | |
1676 | * been received. This function must be called from soft contexts | |
1677 | * not from interrupt context. The driver is responsible for making | |
1678 | * calls one at a time and in order (or using flush_to_ldisc) | |
1679 | * | |
1680 | * Returns the # of input chars from @cp which were processed. | |
1681 | * | |
1682 | * In canonical mode, the maximum line length is 4096 chars (including | |
1683 | * the line termination char); lines longer than 4096 chars are | |
1684 | * truncated. After 4095 chars, input data is still processed but | |
1685 | * not stored. Overflow processing ensures the tty can always | |
1686 | * receive more input until at least one line can be read. | |
1687 | * | |
1688 | * In non-canonical mode, the read buffer will only accept 4095 chars; | |
1689 | * this provides the necessary space for a newline char if the input | |
1690 | * mode is switched to canonical. | |
1691 | * | |
1692 | * Note it is possible for the read buffer to _contain_ 4096 chars | |
1693 | * in non-canonical mode: the read buffer could already contain the | |
1694 | * maximum canon line of 4096 chars when the mode is switched to | |
1695 | * non-canonical. | |
1696 | * | |
1697 | * n_tty_receive_buf()/producer path: | |
1698 | * claims non-exclusive termios_rwsem | |
1699 | * publishes commit_head or canon_head | |
1700 | */ | |
5c32d123 PH |
1701 | static int |
1702 | n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, | |
1703 | char *fp, int count, int flow) | |
24a89d1c PH |
1704 | { |
1705 | struct n_tty_data *ldata = tty->disc_data; | |
fb5ef9e7 | 1706 | int room, n, rcvd = 0, overflow; |
24a89d1c | 1707 | |
9356b535 PH |
1708 | down_read(&tty->termios_rwsem); |
1709 | ||
19e2ad6a | 1710 | while (1) { |
70aca71f | 1711 | /* |
06c49f9f PH |
1712 | * When PARMRK is set, each input char may take up to 3 chars |
1713 | * in the read buf; reduce the buffer space avail by 3x | |
70aca71f PH |
1714 | * |
1715 | * If we are doing input canonicalization, and there are no | |
1716 | * pending newlines, let characters through without limit, so | |
1717 | * that erase characters will be handled. Other excess | |
1718 | * characters will be beeped. | |
1719 | * | |
1720 | * paired with store in *_copy_from_read_buf() -- guarantees | |
1721 | * the consumer has loaded the data in read_buf up to the new | |
1722 | * read_tail (so this producer will not overwrite unread data) | |
1723 | */ | |
1724 | size_t tail = smp_load_acquire(&ldata->read_tail); | |
70aca71f | 1725 | |
fb5ef9e7 | 1726 | room = N_TTY_BUF_SIZE - (ldata->read_head - tail); |
70aca71f | 1727 | if (I_PARMRK(tty)) |
fb5ef9e7 PH |
1728 | room = (room + 2) / 3; |
1729 | room--; | |
1730 | if (room <= 0) { | |
1731 | overflow = ldata->icanon && ldata->canon_head == tail; | |
1732 | if (overflow && room < 0) | |
1733 | ldata->read_head--; | |
1734 | room = overflow; | |
1735 | ldata->no_room = flow && !room; | |
1736 | } else | |
1737 | overflow = 0; | |
70aca71f | 1738 | |
19e2ad6a | 1739 | n = min(count, room); |
fb5ef9e7 | 1740 | if (!n) |
19e2ad6a | 1741 | break; |
fb5ef9e7 PH |
1742 | |
1743 | /* ignore parity errors if handling overflow */ | |
1744 | if (!overflow || !fp || *fp != TTY_PARITY) | |
1745 | __receive_buf(tty, cp, fp, n); | |
1746 | ||
19e2ad6a PH |
1747 | cp += n; |
1748 | if (fp) | |
1749 | fp += n; | |
1750 | count -= n; | |
1751 | rcvd += n; | |
4a23a4df | 1752 | } |
24a89d1c | 1753 | |
19e2ad6a | 1754 | tty->receive_room = room; |
fb5ef9e7 PH |
1755 | |
1756 | /* Unthrottle if handling overflow on pty */ | |
1757 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { | |
1758 | if (overflow) { | |
1759 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1760 | tty_unthrottle_safe(tty); | |
1761 | __tty_set_flow_change(tty, 0); | |
1762 | } | |
1763 | } else | |
1764 | n_tty_check_throttle(tty); | |
1765 | ||
9356b535 PH |
1766 | up_read(&tty->termios_rwsem); |
1767 | ||
19e2ad6a | 1768 | return rcvd; |
24a89d1c PH |
1769 | } |
1770 | ||
5c32d123 PH |
1771 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1772 | char *fp, int count) | |
1773 | { | |
1774 | n_tty_receive_buf_common(tty, cp, fp, count, 0); | |
1775 | } | |
1776 | ||
1777 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1778 | char *fp, int count) | |
1779 | { | |
1780 | return n_tty_receive_buf_common(tty, cp, fp, count, 1); | |
1781 | } | |
1782 | ||
1da177e4 LT |
1783 | int is_ignored(int sig) |
1784 | { | |
1785 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1786 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1787 | } |
1788 | ||
1789 | /** | |
1790 | * n_tty_set_termios - termios data changed | |
1791 | * @tty: terminal | |
1792 | * @old: previous data | |
1793 | * | |
1794 | * Called by the tty layer when the user changes termios flags so | |
1795 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1796 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1797 | * guaranteed that this function will not be re-entered or in progress |
1798 | * when the ldisc is closed. | |
17b82060 | 1799 | * |
6a1c0680 | 1800 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1801 | */ |
4edf1827 AC |
1802 | |
1803 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1804 | { |
53c5ee2c | 1805 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1806 | |
c786f74e | 1807 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { |
3fe780b3 | 1808 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1809 | ldata->line_start = ldata->read_tail; |
1810 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1811 | ldata->canon_head = ldata->read_tail; | |
1812 | ldata->push = 0; | |
1813 | } else { | |
1814 | set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), | |
1815 | ldata->read_flags); | |
1816 | ldata->canon_head = ldata->read_head; | |
1817 | ldata->push = 1; | |
1818 | } | |
70aca71f | 1819 | ldata->commit_head = ldata->read_head; |
53c5ee2c | 1820 | ldata->erasing = 0; |
6f9b028a | 1821 | ldata->lnext = 0; |
47afa7a5 AC |
1822 | } |
1823 | ||
53c5ee2c | 1824 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1825 | |
1da177e4 LT |
1826 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1827 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1828 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1829 | I_PARMRK(tty)) { | |
1bb9d562 | 1830 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1831 | |
1832 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1833 | set_bit('\r', ldata->char_map); |
1da177e4 | 1834 | if (I_INLCR(tty)) |
1bb9d562 | 1835 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1836 | |
1837 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1838 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1839 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1840 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1841 | set_bit('\n', ldata->char_map); | |
1842 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1843 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1844 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1845 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1846 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1847 | if (L_ECHO(tty)) |
1848 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1849 | ldata->char_map); |
1da177e4 LT |
1850 | } |
1851 | } | |
1852 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1853 | set_bit(START_CHAR(tty), ldata->char_map); |
1854 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1855 | } |
1856 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1857 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1858 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1859 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1860 | } |
1bb9d562 | 1861 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1862 | ldata->raw = 0; |
1863 | ldata->real_raw = 0; | |
1da177e4 | 1864 | } else { |
53c5ee2c | 1865 | ldata->raw = 1; |
1da177e4 LT |
1866 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1867 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1868 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1869 | ldata->real_raw = 1; |
1da177e4 | 1870 | else |
53c5ee2c | 1871 | ldata->real_raw = 0; |
1da177e4 | 1872 | } |
dab73b4e WY |
1873 | /* |
1874 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1875 | * been stopped by STOP_CHAR(tty) before it. | |
1876 | */ | |
e2613be5 | 1877 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { |
dab73b4e | 1878 | start_tty(tty); |
e2613be5 PH |
1879 | process_echoes(tty); |
1880 | } | |
dab73b4e | 1881 | |
f34d7a5b | 1882 | /* The termios change make the tty ready for I/O */ |
e81107d4 KT |
1883 | wake_up_interruptible(&tty->write_wait); |
1884 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1885 | } |
1886 | ||
1887 | /** | |
1888 | * n_tty_close - close the ldisc for this tty | |
1889 | * @tty: device | |
1890 | * | |
4edf1827 AC |
1891 | * Called from the terminal layer when this line discipline is |
1892 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1893 | * discipline change. The function will not be called while other |
1894 | * ldisc methods are in progress. | |
1895 | */ | |
4edf1827 | 1896 | |
1da177e4 LT |
1897 | static void n_tty_close(struct tty_struct *tty) |
1898 | { | |
70ece7a7 JS |
1899 | struct n_tty_data *ldata = tty->disc_data; |
1900 | ||
79901317 PH |
1901 | if (tty->link) |
1902 | n_tty_packet_mode_flush(tty); | |
1903 | ||
20bafb3d | 1904 | vfree(ldata); |
70ece7a7 | 1905 | tty->disc_data = NULL; |
1da177e4 LT |
1906 | } |
1907 | ||
1908 | /** | |
1909 | * n_tty_open - open an ldisc | |
1910 | * @tty: terminal to open | |
1911 | * | |
4edf1827 | 1912 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1913 | * terminal device. Can sleep. Called serialized so that no |
1914 | * other events will occur in parallel. No further open will occur | |
1915 | * until a close. | |
1916 | */ | |
1917 | ||
1918 | static int n_tty_open(struct tty_struct *tty) | |
1919 | { | |
70ece7a7 JS |
1920 | struct n_tty_data *ldata; |
1921 | ||
20bafb3d PH |
1922 | /* Currently a malloc failure here can panic */ |
1923 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1924 | if (!ldata) |
1925 | goto err; | |
1926 | ||
53c5ee2c | 1927 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1928 | mutex_init(&ldata->atomic_read_lock); |
1929 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1930 | |
70ece7a7 | 1931 | tty->disc_data = ldata; |
b66f4fa5 | 1932 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1933 | ldata->column = 0; |
20bafb3d | 1934 | ldata->canon_column = 0; |
f6c8dbe6 | 1935 | ldata->minimum_to_wake = 1; |
20bafb3d PH |
1936 | ldata->num_overrun = 0; |
1937 | ldata->no_room = 0; | |
1938 | ldata->lnext = 0; | |
1da177e4 | 1939 | tty->closing = 0; |
b66f4fa5 PH |
1940 | /* indicate buffer work may resume */ |
1941 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1942 | n_tty_set_termios(tty, NULL); | |
1943 | tty_unthrottle(tty); | |
70ece7a7 | 1944 | |
1da177e4 | 1945 | return 0; |
70ece7a7 | 1946 | err: |
b91939f5 | 1947 | return -ENOMEM; |
1da177e4 LT |
1948 | } |
1949 | ||
eafbe67f | 1950 | static inline int input_available_p(struct tty_struct *tty, int poll) |
1da177e4 | 1951 | { |
53c5ee2c | 1952 | struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1953 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1954 | |
25e8d0ed PH |
1955 | if (ldata->icanon && !L_EXTPROC(tty)) |
1956 | return ldata->canon_head != ldata->read_tail; | |
1957 | else | |
70aca71f | 1958 | return ldata->commit_head - ldata->read_tail >= amt; |
1da177e4 LT |
1959 | } |
1960 | ||
1a48632f PH |
1961 | static inline int check_other_done(struct tty_struct *tty) |
1962 | { | |
1963 | int done = test_bit(TTY_OTHER_DONE, &tty->flags); | |
1964 | if (done) { | |
1965 | /* paired with cmpxchg() in check_other_closed(); ensures | |
1966 | * read buffer head index is not stale | |
1967 | */ | |
1968 | smp_mb__after_atomic(); | |
1969 | } | |
1970 | return done; | |
1971 | } | |
1972 | ||
1da177e4 | 1973 | /** |
bbd20759 | 1974 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1975 | * @tty: terminal device |
1976 | * @b: user data | |
1977 | * @nr: size of data | |
1978 | * | |
11a96d18 | 1979 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1980 | * ICANON is off; it copies characters straight from the tty queue to |
1981 | * user space directly. It can be profitably called twice; once to | |
1982 | * drain the space from the tail pointer to the (physical) end of the | |
1983 | * buffer, and once to drain the space from the (physical) beginning of | |
1984 | * the buffer to head pointer. | |
1985 | * | |
bddc7152 | 1986 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1987 | * |
6d76bd26 PH |
1988 | * n_tty_read()/consumer path: |
1989 | * caller holds non-exclusive termios_rwsem | |
1990 | * read_tail published | |
1da177e4 | 1991 | */ |
4edf1827 | 1992 | |
33f0f88f | 1993 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1994 | unsigned char __user **b, |
1995 | size_t *nr) | |
1996 | ||
1997 | { | |
53c5ee2c | 1998 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1999 | int retval; |
2000 | size_t n; | |
3fa10cc8 | 2001 | bool is_eof; |
70aca71f | 2002 | size_t head = smp_load_acquire(&ldata->commit_head); |
bc5a5e3f | 2003 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
2004 | |
2005 | retval = 0; | |
70aca71f | 2006 | n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail); |
1da177e4 | 2007 | n = min(*nr, n); |
1da177e4 | 2008 | if (n) { |
bc5a5e3f | 2009 | retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
1da177e4 | 2010 | n -= retval; |
bc5a5e3f PH |
2011 | is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); |
2012 | tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, | |
53c5ee2c | 2013 | ldata->icanon); |
70aca71f | 2014 | smp_store_release(&ldata->read_tail, ldata->read_tail + n); |
26df6d13 | 2015 | /* Turn single EOF into zero-length read */ |
70aca71f PH |
2016 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && |
2017 | (head == ldata->read_tail)) | |
3fa10cc8 | 2018 | n = 0; |
1da177e4 LT |
2019 | *b += n; |
2020 | *nr -= n; | |
2021 | } | |
2022 | return retval; | |
2023 | } | |
2024 | ||
88bb0de3 | 2025 | /** |
32f13521 | 2026 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
2027 | * @tty: terminal device |
2028 | * @b: user data | |
2029 | * @nr: size of data | |
2030 | * | |
2031 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
2032 | * it copies one line of input up to and including the line-delimiting |
2033 | * character into the user-space buffer. | |
88bb0de3 | 2034 | * |
4d0ed182 PH |
2035 | * NB: When termios is changed from non-canonical to canonical mode and |
2036 | * the read buffer contains data, n_tty_set_termios() simulates an EOF | |
2037 | * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. | |
2038 | * This causes data already processed as input to be immediately available | |
2039 | * as input although a newline has not been received. | |
2040 | * | |
88bb0de3 | 2041 | * Called under the atomic_read_lock mutex |
6d76bd26 PH |
2042 | * |
2043 | * n_tty_read()/consumer path: | |
2044 | * caller holds non-exclusive termios_rwsem | |
2045 | * read_tail published | |
88bb0de3 PH |
2046 | */ |
2047 | ||
32f13521 PH |
2048 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
2049 | unsigned char __user **b, | |
2050 | size_t *nr) | |
88bb0de3 PH |
2051 | { |
2052 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 2053 | size_t n, size, more, c; |
bc5a5e3f PH |
2054 | size_t eol; |
2055 | size_t tail; | |
2056 | int ret, found = 0; | |
40d5e090 | 2057 | bool eof_push = 0; |
88bb0de3 PH |
2058 | |
2059 | /* N.B. avoid overrun if nr == 0 */ | |
70aca71f | 2060 | n = min(*nr, smp_load_acquire(&ldata->canon_head) - ldata->read_tail); |
6d76bd26 | 2061 | if (!n) |
32f13521 | 2062 | return 0; |
88bb0de3 | 2063 | |
bc5a5e3f | 2064 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
2065 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
2066 | ||
bc5a5e3f | 2067 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2068 | __func__, *nr, tail, n, size); |
2069 | ||
2070 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2071 | more = n - (size - tail); | |
2072 | if (eol == N_TTY_BUF_SIZE && more) { | |
2073 | /* scan wrapped without finding set bit */ | |
2074 | eol = find_next_bit(ldata->read_flags, more, 0); | |
2075 | if (eol != more) | |
2076 | found = 1; | |
2077 | } else if (eol != size) | |
2078 | found = 1; | |
2079 | ||
2080 | size = N_TTY_BUF_SIZE - tail; | |
c77569d2 | 2081 | n = eol - tail; |
da555db6 MT |
2082 | if (n > N_TTY_BUF_SIZE) |
2083 | n += N_TTY_BUF_SIZE; | |
c77569d2 | 2084 | n += found; |
32f13521 PH |
2085 | c = n; |
2086 | ||
4d0ed182 | 2087 | if (found && !ldata->push && read_buf(ldata, eol) == __DISABLED_CHAR) { |
32f13521 | 2088 | n--; |
40d5e090 PH |
2089 | eof_push = !n && ldata->read_tail != ldata->line_start; |
2090 | } | |
32f13521 | 2091 | |
bc5a5e3f | 2092 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", |
32f13521 PH |
2093 | __func__, eol, found, n, c, size, more); |
2094 | ||
32f13521 | 2095 | if (n > size) { |
72586c60 | 2096 | ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), size); |
32f13521 PH |
2097 | if (ret) |
2098 | return -EFAULT; | |
72586c60 | 2099 | ret = tty_copy_to_user(tty, *b + size, ldata->read_buf, n - size); |
32f13521 | 2100 | } else |
72586c60 | 2101 | ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), n); |
32f13521 PH |
2102 | |
2103 | if (ret) | |
2104 | return -EFAULT; | |
2105 | *b += n; | |
2106 | *nr -= n; | |
2107 | ||
a73d3d69 | 2108 | if (found) |
6d76bd26 | 2109 | clear_bit(eol, ldata->read_flags); |
70aca71f | 2110 | smp_store_release(&ldata->read_tail, ldata->read_tail + c); |
88bb0de3 | 2111 | |
40d5e090 | 2112 | if (found) { |
4d0ed182 PH |
2113 | if (!ldata->push) |
2114 | ldata->line_start = ldata->read_tail; | |
2115 | else | |
2116 | ldata->push = 0; | |
32f13521 | 2117 | tty_audit_push(tty); |
40d5e090 PH |
2118 | } |
2119 | return eof_push ? -EAGAIN : 0; | |
88bb0de3 PH |
2120 | } |
2121 | ||
cc4191dc | 2122 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2123 | size_t, loff_t *); |
1da177e4 LT |
2124 | |
2125 | /** | |
2126 | * job_control - check job control | |
2127 | * @tty: tty | |
2128 | * @file: file handle | |
2129 | * | |
2130 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2131 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2132 | * error code if action should be taken. |
04f378b1 | 2133 | * |
01a5e440 PH |
2134 | * Locking: redirected write test is safe |
2135 | * current->signal->tty check is safe | |
2136 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2137 | */ |
4edf1827 | 2138 | |
1da177e4 LT |
2139 | static int job_control(struct tty_struct *tty, struct file *file) |
2140 | { | |
2141 | /* Job control check -- must be done at start and after | |
2142 | every sleep (POSIX.1 7.1.1.4). */ | |
2143 | /* NOTE: not yet done after every sleep pending a thorough | |
2144 | check of the logic of this change. -- jlc */ | |
2145 | /* don't stop on /dev/console */ | |
2812d9e9 | 2146 | if (file->f_op->write == redirected_tty_write) |
01a5e440 PH |
2147 | return 0; |
2148 | ||
2812d9e9 | 2149 | return __tty_check_change(tty, SIGTTIN); |
1da177e4 | 2150 | } |
4edf1827 | 2151 | |
1da177e4 LT |
2152 | |
2153 | /** | |
11a96d18 | 2154 | * n_tty_read - read function for tty |
1da177e4 LT |
2155 | * @tty: tty device |
2156 | * @file: file object | |
2157 | * @buf: userspace buffer pointer | |
2158 | * @nr: size of I/O | |
2159 | * | |
2160 | * Perform reads for the line discipline. We are guaranteed that the | |
2161 | * line discipline will not be closed under us but we may get multiple | |
2162 | * parallel readers and must handle this ourselves. We may also get | |
2163 | * a hangup. Always called in user context, may sleep. | |
2164 | * | |
2165 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2166 | * |
2167 | * n_tty_read()/consumer path: | |
2168 | * claims non-exclusive termios_rwsem | |
2169 | * publishes read_tail | |
1da177e4 | 2170 | */ |
4edf1827 | 2171 | |
11a96d18 | 2172 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2173 | unsigned char __user *buf, size_t nr) |
2174 | { | |
53c5ee2c | 2175 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 2176 | unsigned char __user *b = buf; |
97d9e28d | 2177 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1a48632f | 2178 | int c, done; |
1da177e4 LT |
2179 | int minimum, time; |
2180 | ssize_t retval = 0; | |
1da177e4 | 2181 | long timeout; |
04f378b1 | 2182 | int packet; |
2c5dc464 | 2183 | size_t tail; |
1da177e4 | 2184 | |
1da177e4 | 2185 | c = job_control(tty, file); |
4edf1827 | 2186 | if (c < 0) |
1da177e4 | 2187 | return c; |
4edf1827 | 2188 | |
aefceaf4 PH |
2189 | /* |
2190 | * Internal serialization of reads. | |
2191 | */ | |
2192 | if (file->f_flags & O_NONBLOCK) { | |
2193 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2194 | return -EAGAIN; | |
2195 | } else { | |
2196 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2197 | return -ERESTARTSYS; | |
2198 | } | |
2199 | ||
9356b535 PH |
2200 | down_read(&tty->termios_rwsem); |
2201 | ||
1da177e4 LT |
2202 | minimum = time = 0; |
2203 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2204 | if (!ldata->icanon) { |
1da177e4 LT |
2205 | minimum = MIN_CHAR(tty); |
2206 | if (minimum) { | |
a6e54319 | 2207 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2208 | if (time) |
f6c8dbe6 | 2209 | ldata->minimum_to_wake = 1; |
1da177e4 | 2210 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
2211 | (ldata->minimum_to_wake > minimum)) |
2212 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 2213 | } else { |
a6e54319 | 2214 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2215 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2216 | } |
2217 | } | |
2218 | ||
04f378b1 | 2219 | packet = tty->packet; |
2c5dc464 | 2220 | tail = ldata->read_tail; |
1da177e4 LT |
2221 | |
2222 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2223 | while (nr) { |
2224 | /* First test for status change. */ | |
04f378b1 | 2225 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2226 | unsigned char cs; |
2227 | if (b != buf) | |
2228 | break; | |
6054c16e | 2229 | spin_lock_irq(&tty->link->ctrl_lock); |
1da177e4 LT |
2230 | cs = tty->link->ctrl_status; |
2231 | tty->link->ctrl_status = 0; | |
6054c16e | 2232 | spin_unlock_irq(&tty->link->ctrl_lock); |
522ed776 | 2233 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2234 | retval = -EFAULT; |
2235 | b--; | |
2236 | break; | |
2237 | } | |
2238 | nr--; | |
2239 | break; | |
2240 | } | |
4edf1827 | 2241 | |
f6c8dbe6 | 2242 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2243 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2244 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2245 | |
1a48632f PH |
2246 | done = check_other_done(tty); |
2247 | ||
1da177e4 | 2248 | if (!input_available_p(tty, 0)) { |
1a48632f | 2249 | if (done) { |
52bce7f8 PH |
2250 | retval = -EIO; |
2251 | break; | |
f8747d4a | 2252 | } |
52bce7f8 PH |
2253 | if (tty_hung_up_p(file)) |
2254 | break; | |
2255 | if (!timeout) | |
2256 | break; | |
2257 | if (file->f_flags & O_NONBLOCK) { | |
2258 | retval = -EAGAIN; | |
1da177e4 LT |
2259 | break; |
2260 | } | |
52bce7f8 PH |
2261 | if (signal_pending(current)) { |
2262 | retval = -ERESTARTSYS; | |
2263 | break; | |
2264 | } | |
52bce7f8 | 2265 | up_read(&tty->termios_rwsem); |
9356b535 | 2266 | |
37da7bbb LT |
2267 | timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, |
2268 | timeout); | |
9356b535 | 2269 | |
52bce7f8 PH |
2270 | down_read(&tty->termios_rwsem); |
2271 | continue; | |
1da177e4 LT |
2272 | } |
2273 | ||
53c5ee2c | 2274 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2275 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
40d5e090 PH |
2276 | if (retval == -EAGAIN) { |
2277 | retval = 0; | |
2278 | continue; | |
2279 | } else if (retval) | |
1da177e4 LT |
2280 | break; |
2281 | } else { | |
2282 | int uncopied; | |
95ea90db PH |
2283 | |
2284 | /* Deal with packet mode. */ | |
2285 | if (packet && b == buf) { | |
2286 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { | |
2287 | retval = -EFAULT; | |
2288 | b--; | |
2289 | break; | |
2290 | } | |
2291 | nr--; | |
2292 | } | |
2293 | ||
1da177e4 LT |
2294 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2295 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2296 | if (uncopied) { | |
2297 | retval = -EFAULT; | |
2298 | break; | |
2299 | } | |
2300 | } | |
2301 | ||
6367ca72 | 2302 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2303 | |
2304 | if (b - buf >= minimum) | |
2305 | break; | |
2306 | if (time) | |
2307 | timeout = time; | |
2308 | } | |
2c5dc464 PH |
2309 | if (tail != ldata->read_tail) |
2310 | n_tty_kick_worker(tty); | |
42458f41 PH |
2311 | up_read(&tty->termios_rwsem); |
2312 | ||
1da177e4 | 2313 | remove_wait_queue(&tty->read_wait, &wait); |
1da177e4 | 2314 | if (!waitqueue_active(&tty->read_wait)) |
f6c8dbe6 | 2315 | ldata->minimum_to_wake = minimum; |
1da177e4 | 2316 | |
aebf0453 PH |
2317 | mutex_unlock(&ldata->atomic_read_lock); |
2318 | ||
40d5e090 PH |
2319 | if (b - buf) |
2320 | retval = b - buf; | |
1da177e4 LT |
2321 | |
2322 | return retval; | |
2323 | } | |
2324 | ||
2325 | /** | |
11a96d18 | 2326 | * n_tty_write - write function for tty |
1da177e4 LT |
2327 | * @tty: tty device |
2328 | * @file: file object | |
2329 | * @buf: userspace buffer pointer | |
2330 | * @nr: size of I/O | |
2331 | * | |
a88a69c9 | 2332 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2333 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2334 | * and other such events. Since the receive code will echo characters, |
2335 | * thus calling driver write methods, the output_lock is used in | |
2336 | * the output processing functions called here as well as in the | |
2337 | * echo processing function to protect the column state and space | |
2338 | * left in the buffer. | |
1da177e4 LT |
2339 | * |
2340 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2341 | * |
2342 | * Locking: output_lock to protect column state and space left | |
2343 | * (note that the process_output*() functions take this | |
2344 | * lock themselves) | |
1da177e4 | 2345 | */ |
4edf1827 | 2346 | |
11a96d18 | 2347 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2348 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2349 | { |
2350 | const unsigned char *b = buf; | |
97d9e28d | 2351 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2352 | int c; |
2353 | ssize_t retval = 0; | |
2354 | ||
2355 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2356 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2357 | retval = tty_check_change(tty); | |
2358 | if (retval) | |
2359 | return retval; | |
2360 | } | |
2361 | ||
9356b535 PH |
2362 | down_read(&tty->termios_rwsem); |
2363 | ||
a88a69c9 JP |
2364 | /* Write out any echoed characters that are still pending */ |
2365 | process_echoes(tty); | |
300a6204 | 2366 | |
1da177e4 LT |
2367 | add_wait_queue(&tty->write_wait, &wait); |
2368 | while (1) { | |
1da177e4 LT |
2369 | if (signal_pending(current)) { |
2370 | retval = -ERESTARTSYS; | |
2371 | break; | |
2372 | } | |
2373 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2374 | retval = -EIO; | |
2375 | break; | |
2376 | } | |
582f5590 | 2377 | if (O_OPOST(tty)) { |
1da177e4 | 2378 | while (nr > 0) { |
a88a69c9 | 2379 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2380 | if (num < 0) { |
2381 | if (num == -EAGAIN) | |
2382 | break; | |
2383 | retval = num; | |
2384 | goto break_out; | |
2385 | } | |
2386 | b += num; | |
2387 | nr -= num; | |
2388 | if (nr == 0) | |
2389 | break; | |
2390 | c = *b; | |
a88a69c9 | 2391 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2392 | break; |
2393 | b++; nr--; | |
2394 | } | |
f34d7a5b AC |
2395 | if (tty->ops->flush_chars) |
2396 | tty->ops->flush_chars(tty); | |
1da177e4 | 2397 | } else { |
4291086b PH |
2398 | struct n_tty_data *ldata = tty->disc_data; |
2399 | ||
d6afe27b | 2400 | while (nr > 0) { |
4291086b | 2401 | mutex_lock(&ldata->output_lock); |
f34d7a5b | 2402 | c = tty->ops->write(tty, b, nr); |
4291086b | 2403 | mutex_unlock(&ldata->output_lock); |
d6afe27b RZ |
2404 | if (c < 0) { |
2405 | retval = c; | |
2406 | goto break_out; | |
2407 | } | |
2408 | if (!c) | |
2409 | break; | |
2410 | b += c; | |
2411 | nr -= c; | |
1da177e4 | 2412 | } |
1da177e4 LT |
2413 | } |
2414 | if (!nr) | |
2415 | break; | |
2416 | if (file->f_flags & O_NONBLOCK) { | |
2417 | retval = -EAGAIN; | |
2418 | break; | |
2419 | } | |
9356b535 PH |
2420 | up_read(&tty->termios_rwsem); |
2421 | ||
97d9e28d | 2422 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
9356b535 PH |
2423 | |
2424 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2425 | } |
2426 | break_out: | |
1da177e4 | 2427 | remove_wait_queue(&tty->write_wait, &wait); |
ff8cb0fd TP |
2428 | if (b - buf != nr && tty->fasync) |
2429 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2430 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2431 | return (b - buf) ? b - buf : retval; |
2432 | } | |
2433 | ||
2434 | /** | |
11a96d18 | 2435 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2436 | * @tty: terminal device |
2437 | * @file: file accessing it | |
2438 | * @wait: poll table | |
2439 | * | |
2440 | * Called when the line discipline is asked to poll() for data or | |
2441 | * for special events. This code is not serialized with respect to | |
2442 | * other events save open/close. | |
2443 | * | |
2444 | * This code must be sure never to sleep through a hangup. | |
2445 | * Called without the kernel lock held - fine | |
1da177e4 | 2446 | */ |
4edf1827 | 2447 | |
11a96d18 | 2448 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2449 | poll_table *wait) |
1da177e4 | 2450 | { |
f6c8dbe6 | 2451 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2452 | unsigned int mask = 0; |
2453 | ||
2454 | poll_wait(file, &tty->read_wait, wait); | |
2455 | poll_wait(file, &tty->write_wait, wait); | |
1a48632f PH |
2456 | if (check_other_done(tty)) |
2457 | mask |= POLLHUP; | |
eafbe67f | 2458 | if (input_available_p(tty, 1)) |
1da177e4 LT |
2459 | mask |= POLLIN | POLLRDNORM; |
2460 | if (tty->packet && tty->link->ctrl_status) | |
2461 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
1da177e4 LT |
2462 | if (tty_hung_up_p(file)) |
2463 | mask |= POLLHUP; | |
2464 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2465 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2466 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2467 | else |
f6c8dbe6 | 2468 | ldata->minimum_to_wake = 1; |
1da177e4 | 2469 | } |
f34d7a5b AC |
2470 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2471 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2472 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2473 | mask |= POLLOUT | POLLWRNORM; |
2474 | return mask; | |
2475 | } | |
2476 | ||
57c94121 | 2477 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2478 | { |
bc5a5e3f | 2479 | size_t nr, head, tail; |
47afa7a5 | 2480 | |
a73d3d69 | 2481 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2482 | return 0; |
ba2e68ac JS |
2483 | head = ldata->canon_head; |
2484 | tail = ldata->read_tail; | |
bc5a5e3f | 2485 | nr = head - tail; |
47afa7a5 AC |
2486 | /* Skip EOF-chars.. */ |
2487 | while (head != tail) { | |
bc5a5e3f PH |
2488 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2489 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2490 | nr--; |
bc5a5e3f | 2491 | tail++; |
47afa7a5 AC |
2492 | } |
2493 | return nr; | |
2494 | } | |
2495 | ||
2496 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2497 | unsigned int cmd, unsigned long arg) | |
2498 | { | |
ba2e68ac | 2499 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2500 | int retval; |
2501 | ||
2502 | switch (cmd) { | |
2503 | case TIOCOUTQ: | |
2504 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2505 | case TIOCINQ: | |
6d76bd26 | 2506 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2507 | if (L_ICANON(tty)) |
57c94121 | 2508 | retval = inq_canon(ldata); |
6d76bd26 PH |
2509 | else |
2510 | retval = read_cnt(ldata); | |
2511 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2512 | return put_user(retval, (unsigned int __user *) arg); |
2513 | default: | |
2514 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2515 | } | |
2516 | } | |
2517 | ||
f6c8dbe6 PH |
2518 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2519 | { | |
2520 | struct n_tty_data *ldata = tty->disc_data; | |
2521 | ||
2522 | if (!waitqueue_active(&tty->read_wait)) { | |
2523 | if (on) | |
2524 | ldata->minimum_to_wake = 1; | |
2525 | else if (!tty->fasync) | |
2526 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2527 | } | |
2528 | } | |
2529 | ||
a352def2 | 2530 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2531 | .magic = TTY_LDISC_MAGIC, |
2532 | .name = "n_tty", | |
2533 | .open = n_tty_open, | |
2534 | .close = n_tty_close, | |
2535 | .flush_buffer = n_tty_flush_buffer, | |
2536 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2537 | .read = n_tty_read, |
2538 | .write = n_tty_write, | |
e10cc1df PF |
2539 | .ioctl = n_tty_ioctl, |
2540 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2541 | .poll = n_tty_poll, |
e10cc1df | 2542 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2543 | .write_wakeup = n_tty_write_wakeup, |
2544 | .fasync = n_tty_fasync, | |
24a89d1c | 2545 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2546 | }; |
572b9adb RG |
2547 | |
2548 | /** | |
2549 | * n_tty_inherit_ops - inherit N_TTY methods | |
2550 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2551 | * | |
593fb1ae | 2552 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2553 | * methods. |
2554 | */ | |
2555 | ||
2556 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2557 | { | |
2558 | *ops = tty_ldisc_N_TTY; | |
2559 | ops->owner = NULL; | |
2560 | ops->refcount = ops->flags = 0; | |
2561 | } | |
2562 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |