]>
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 | ||
24a89d1c | 165 | /** |
2c5dc464 | 166 | * n_tty_kick_worker - start input worker (if required) |
24a89d1c PH |
167 | * @tty: terminal |
168 | * | |
2c5dc464 | 169 | * Re-schedules the flip buffer work if it may have stopped |
24a89d1c | 170 | * |
6d76bd26 PH |
171 | * Caller holds exclusive termios_rwsem |
172 | * or | |
173 | * n_tty_read()/consumer path: | |
174 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
175 | */ |
176 | ||
2c5dc464 | 177 | static void n_tty_kick_worker(struct tty_struct *tty) |
7879a9f9 | 178 | { |
24a89d1c PH |
179 | struct n_tty_data *ldata = tty->disc_data; |
180 | ||
2c5dc464 PH |
181 | /* Did the input worker stop? Restart it */ |
182 | if (unlikely(ldata->no_room)) { | |
24a89d1c PH |
183 | ldata->no_room = 0; |
184 | ||
ecbbfd44 | 185 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 186 | "scheduling with invalid itty\n"); |
21622939 PH |
187 | /* see if ldisc has been killed - if so, this means that |
188 | * even though the ldisc has been halted and ->buf.work | |
189 | * cancelled, ->buf.work is about to be rescheduled | |
190 | */ | |
191 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
192 | "scheduling buffer work for halted ldisc\n"); | |
f0f947c1 | 193 | queue_work(system_unbound_wq, &tty->port->buf.work); |
ecbbfd44 | 194 | } |
55db4c64 LT |
195 | } |
196 | ||
9a4aec2d PH |
197 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
198 | { | |
199 | struct n_tty_data *ldata = tty->disc_data; | |
200 | ssize_t n = 0; | |
201 | ||
202 | if (!ldata->icanon) | |
70aca71f | 203 | n = ldata->commit_head - ldata->read_tail; |
9a4aec2d PH |
204 | else |
205 | n = ldata->canon_head - ldata->read_tail; | |
206 | return n; | |
207 | } | |
208 | ||
ee0bab83 PH |
209 | /** |
210 | * n_tty_write_wakeup - asynchronous I/O notifier | |
211 | * @tty: tty device | |
212 | * | |
213 | * Required for the ptys, serial driver etc. since processes | |
214 | * that attach themselves to the master and rely on ASYNC | |
215 | * IO must be woken up | |
216 | */ | |
217 | ||
218 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
219 | { | |
220 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) | |
221 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
222 | } | |
223 | ||
4a23a4df | 224 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 225 | { |
a342846f PH |
226 | struct n_tty_data *ldata = tty->disc_data; |
227 | ||
6367ca72 PH |
228 | /* |
229 | * Check the remaining room for the input canonicalization | |
230 | * mode. We don't want to throttle the driver if we're in | |
231 | * canonical mode and don't have a newline yet! | |
232 | */ | |
a342846f PH |
233 | if (ldata->icanon && ldata->canon_head == ldata->read_tail) |
234 | return; | |
235 | ||
6367ca72 PH |
236 | while (1) { |
237 | int throttled; | |
238 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
5e28cca1 | 239 | if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE) |
6367ca72 PH |
240 | break; |
241 | throttled = tty_throttle_safe(tty); | |
242 | if (!throttled) | |
243 | break; | |
244 | } | |
245 | __tty_set_flow_change(tty, 0); | |
246 | } | |
247 | ||
4b293492 | 248 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 249 | { |
3afb1b39 PH |
250 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
251 | tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { | |
252 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
253 | return; | |
254 | if (!tty->count) | |
255 | return; | |
2c5dc464 | 256 | n_tty_kick_worker(tty); |
3afb1b39 | 257 | n_tty_write_wakeup(tty->link); |
6c67716d PH |
258 | if (waitqueue_active(&tty->link->write_wait)) |
259 | wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); | |
3afb1b39 PH |
260 | return; |
261 | } | |
262 | ||
6367ca72 PH |
263 | /* If there is enough space in the read buffer now, let the |
264 | * low-level driver know. We use chars_in_buffer() to | |
265 | * check the buffer, as it now knows about canonical mode. | |
266 | * Otherwise, if the driver is throttled and the line is | |
267 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
268 | * we won't get any more characters. | |
269 | */ | |
270 | ||
271 | while (1) { | |
272 | int unthrottled; | |
273 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
274 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
275 | break; | |
276 | if (!tty->count) | |
277 | break; | |
2c5dc464 | 278 | n_tty_kick_worker(tty); |
6367ca72 PH |
279 | unthrottled = tty_unthrottle_safe(tty); |
280 | if (!unthrottled) | |
281 | break; | |
282 | } | |
283 | __tty_set_flow_change(tty, 0); | |
284 | } | |
285 | ||
17b82060 AC |
286 | /** |
287 | * put_tty_queue - add character to tty | |
288 | * @c: character | |
57c94121 | 289 | * @ldata: n_tty data |
17b82060 | 290 | * |
6d76bd26 PH |
291 | * Add a character to the tty read_buf queue. |
292 | * | |
293 | * n_tty_receive_buf()/producer path: | |
294 | * caller holds non-exclusive termios_rwsem | |
17b82060 AC |
295 | */ |
296 | ||
19e2ad6a | 297 | static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 298 | { |
8bfbe2de CR |
299 | *read_buf_addr(ldata, ldata->read_head) = c; |
300 | ldata->read_head++; | |
1da177e4 LT |
301 | } |
302 | ||
1da177e4 LT |
303 | /** |
304 | * reset_buffer_flags - reset buffer state | |
305 | * @tty: terminal to reset | |
306 | * | |
25518c68 PH |
307 | * Reset the read buffer counters and clear the flags. |
308 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 309 | * |
6d76bd26 PH |
310 | * Locking: caller holds exclusive termios_rwsem |
311 | * (or locking is not required) | |
1da177e4 | 312 | */ |
a88a69c9 | 313 | |
b66f4fa5 | 314 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 315 | { |
a73d3d69 | 316 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 317 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
70aca71f | 318 | ldata->commit_head = 0; |
1075a6e2 | 319 | ldata->echo_mark = 0; |
40d5e090 | 320 | ldata->line_start = 0; |
a88a69c9 | 321 | |
a73d3d69 | 322 | ldata->erasing = 0; |
3fe780b3 | 323 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 | 324 | ldata->push = 0; |
1da177e4 LT |
325 | } |
326 | ||
a30737ab PH |
327 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
328 | { | |
329 | unsigned long flags; | |
330 | ||
a30737ab | 331 | if (tty->link->packet) { |
54e8e5fc | 332 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
a30737ab | 333 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; |
54e8e5fc | 334 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
6c67716d PH |
335 | if (waitqueue_active(&tty->link->read_wait)) |
336 | wake_up_interruptible(&tty->link->read_wait); | |
a30737ab | 337 | } |
a30737ab PH |
338 | } |
339 | ||
1da177e4 LT |
340 | /** |
341 | * n_tty_flush_buffer - clean input queue | |
342 | * @tty: terminal device | |
343 | * | |
25518c68 PH |
344 | * Flush the input buffer. Called when the tty layer wants the |
345 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
346 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 347 | * |
6d76bd26 PH |
348 | * Holds termios_rwsem to exclude producer/consumer while |
349 | * buffer indices are reset. | |
350 | * | |
351 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 352 | */ |
4edf1827 AC |
353 | |
354 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 355 | { |
6d76bd26 | 356 | down_write(&tty->termios_rwsem); |
b66f4fa5 | 357 | reset_buffer_flags(tty->disc_data); |
2c5dc464 | 358 | n_tty_kick_worker(tty); |
4edf1827 | 359 | |
a30737ab PH |
360 | if (tty->link) |
361 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 362 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
363 | } |
364 | ||
6d76bd26 PH |
365 | /** |
366 | * n_tty_chars_in_buffer - report available bytes | |
367 | * @tty: tty device | |
368 | * | |
369 | * Report the number of characters buffered to be delivered to user | |
370 | * at this instant in time. | |
371 | * | |
372 | * Locking: exclusive termios_rwsem | |
373 | */ | |
374 | ||
a19d0c6a PH |
375 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
376 | { | |
6d76bd26 PH |
377 | ssize_t n; |
378 | ||
47534084 | 379 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
6d76bd26 PH |
380 | |
381 | down_write(&tty->termios_rwsem); | |
382 | n = chars_in_buffer(tty); | |
383 | up_write(&tty->termios_rwsem); | |
384 | return n; | |
a19d0c6a PH |
385 | } |
386 | ||
1da177e4 LT |
387 | /** |
388 | * is_utf8_continuation - utf8 multibyte check | |
389 | * @c: byte to check | |
390 | * | |
391 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
392 | * character. We use this to correctly compute the on screen size | |
393 | * of the character when printing | |
394 | */ | |
4edf1827 | 395 | |
1da177e4 LT |
396 | static inline int is_utf8_continuation(unsigned char c) |
397 | { | |
398 | return (c & 0xc0) == 0x80; | |
399 | } | |
400 | ||
401 | /** | |
402 | * is_continuation - multibyte check | |
403 | * @c: byte to check | |
404 | * | |
405 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
406 | * character and the terminal is in unicode mode. | |
407 | */ | |
4edf1827 | 408 | |
1da177e4 LT |
409 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
410 | { | |
411 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
412 | } | |
413 | ||
414 | /** | |
a88a69c9 | 415 | * do_output_char - output one character |
1da177e4 LT |
416 | * @c: character (or partial unicode symbol) |
417 | * @tty: terminal device | |
a88a69c9 | 418 | * @space: space available in tty driver write buffer |
1da177e4 | 419 | * |
a88a69c9 JP |
420 | * This is a helper function that handles one output character |
421 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
422 | * doing OPOST processing and putting the results in the |
423 | * tty driver's write buffer. | |
a88a69c9 JP |
424 | * |
425 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
426 | * and NLDLY. They simply aren't relevant in the world today. | |
427 | * If you ever need them, add them here. | |
1da177e4 | 428 | * |
a88a69c9 JP |
429 | * Returns the number of bytes of buffer space used or -1 if |
430 | * no space left. | |
431 | * | |
432 | * Locking: should be called under the output_lock to protect | |
433 | * the column state and space left in the buffer | |
1da177e4 | 434 | */ |
4edf1827 | 435 | |
a88a69c9 | 436 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 437 | { |
53c5ee2c | 438 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 439 | int spaces; |
1da177e4 | 440 | |
1da177e4 LT |
441 | if (!space) |
442 | return -1; | |
300a6204 | 443 | |
a88a69c9 JP |
444 | switch (c) { |
445 | case '\n': | |
446 | if (O_ONLRET(tty)) | |
53c5ee2c | 447 | ldata->column = 0; |
a88a69c9 JP |
448 | if (O_ONLCR(tty)) { |
449 | if (space < 2) | |
450 | return -1; | |
ba2e68ac | 451 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 452 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
453 | return 2; |
454 | } | |
ba2e68ac | 455 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
456 | break; |
457 | case '\r': | |
53c5ee2c | 458 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
459 | return 0; |
460 | if (O_OCRNL(tty)) { | |
461 | c = '\n'; | |
462 | if (O_ONLRET(tty)) | |
ba2e68ac | 463 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 464 | break; |
a88a69c9 | 465 | } |
ba2e68ac | 466 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
467 | break; |
468 | case '\t': | |
53c5ee2c | 469 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
470 | if (O_TABDLY(tty) == XTABS) { |
471 | if (space < spaces) | |
472 | return -1; | |
53c5ee2c | 473 | ldata->column += spaces; |
a88a69c9 JP |
474 | tty->ops->write(tty, " ", spaces); |
475 | return spaces; | |
1da177e4 | 476 | } |
53c5ee2c | 477 | ldata->column += spaces; |
a88a69c9 JP |
478 | break; |
479 | case '\b': | |
53c5ee2c JS |
480 | if (ldata->column > 0) |
481 | ldata->column--; | |
a88a69c9 JP |
482 | break; |
483 | default: | |
a59c0d6f JP |
484 | if (!iscntrl(c)) { |
485 | if (O_OLCUC(tty)) | |
486 | c = toupper(c); | |
487 | if (!is_continuation(c, tty)) | |
53c5ee2c | 488 | ldata->column++; |
a59c0d6f | 489 | } |
a88a69c9 | 490 | break; |
1da177e4 | 491 | } |
a88a69c9 | 492 | |
f34d7a5b | 493 | tty_put_char(tty, c); |
a88a69c9 JP |
494 | return 1; |
495 | } | |
496 | ||
497 | /** | |
498 | * process_output - output post processor | |
499 | * @c: character (or partial unicode symbol) | |
500 | * @tty: terminal device | |
501 | * | |
ee5aa7b8 JP |
502 | * Output one character with OPOST processing. |
503 | * Returns -1 when the output device is full and the character | |
504 | * must be retried. | |
a88a69c9 JP |
505 | * |
506 | * Locking: output_lock to protect column state and space left | |
507 | * (also, this is called from n_tty_write under the | |
508 | * tty layer write lock) | |
509 | */ | |
510 | ||
511 | static int process_output(unsigned char c, struct tty_struct *tty) | |
512 | { | |
bddc7152 | 513 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
514 | int space, retval; |
515 | ||
bddc7152 | 516 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
517 | |
518 | space = tty_write_room(tty); | |
519 | retval = do_output_char(c, tty, space); | |
520 | ||
bddc7152 | 521 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
522 | if (retval < 0) |
523 | return -1; | |
524 | else | |
525 | return 0; | |
1da177e4 LT |
526 | } |
527 | ||
528 | /** | |
a88a69c9 | 529 | * process_output_block - block post processor |
1da177e4 | 530 | * @tty: terminal device |
ee5aa7b8 JP |
531 | * @buf: character buffer |
532 | * @nr: number of bytes to output | |
533 | * | |
534 | * Output a block of characters with OPOST processing. | |
535 | * Returns the number of characters output. | |
1da177e4 LT |
536 | * |
537 | * This path is used to speed up block console writes, among other | |
538 | * things when processing blocks of output data. It handles only | |
539 | * the simple cases normally found and helps to generate blocks of | |
540 | * symbols for the console driver and thus improve performance. | |
541 | * | |
a88a69c9 JP |
542 | * Locking: output_lock to protect column state and space left |
543 | * (also, this is called from n_tty_write under the | |
544 | * tty layer write lock) | |
1da177e4 | 545 | */ |
4edf1827 | 546 | |
a88a69c9 JP |
547 | static ssize_t process_output_block(struct tty_struct *tty, |
548 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 549 | { |
53c5ee2c | 550 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 551 | int space; |
bbd20759 | 552 | int i; |
1da177e4 LT |
553 | const unsigned char *cp; |
554 | ||
bddc7152 | 555 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 556 | |
f34d7a5b | 557 | space = tty_write_room(tty); |
300a6204 | 558 | if (!space) { |
bddc7152 | 559 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 560 | return 0; |
a88a69c9 | 561 | } |
1da177e4 LT |
562 | if (nr > space) |
563 | nr = space; | |
564 | ||
565 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
566 | unsigned char c = *cp; |
567 | ||
568 | switch (c) { | |
1da177e4 LT |
569 | case '\n': |
570 | if (O_ONLRET(tty)) | |
53c5ee2c | 571 | ldata->column = 0; |
1da177e4 LT |
572 | if (O_ONLCR(tty)) |
573 | goto break_out; | |
ba2e68ac | 574 | ldata->canon_column = ldata->column; |
1da177e4 LT |
575 | break; |
576 | case '\r': | |
53c5ee2c | 577 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
578 | goto break_out; |
579 | if (O_OCRNL(tty)) | |
580 | goto break_out; | |
ba2e68ac | 581 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
582 | break; |
583 | case '\t': | |
584 | goto break_out; | |
585 | case '\b': | |
53c5ee2c JS |
586 | if (ldata->column > 0) |
587 | ldata->column--; | |
1da177e4 LT |
588 | break; |
589 | default: | |
a59c0d6f JP |
590 | if (!iscntrl(c)) { |
591 | if (O_OLCUC(tty)) | |
592 | goto break_out; | |
593 | if (!is_continuation(c, tty)) | |
53c5ee2c | 594 | ldata->column++; |
a59c0d6f | 595 | } |
1da177e4 LT |
596 | break; |
597 | } | |
598 | } | |
599 | break_out: | |
f34d7a5b | 600 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 601 | |
bddc7152 | 602 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
603 | return i; |
604 | } | |
605 | ||
a88a69c9 JP |
606 | /** |
607 | * process_echoes - write pending echo characters | |
608 | * @tty: terminal device | |
609 | * | |
610 | * Write previously buffered echo (and other ldisc-generated) | |
611 | * characters to the tty. | |
612 | * | |
613 | * Characters generated by the ldisc (including echoes) need to | |
614 | * be buffered because the driver's write buffer can fill during | |
615 | * heavy program output. Echoing straight to the driver will | |
616 | * often fail under these conditions, causing lost characters and | |
617 | * resulting mismatches of ldisc state information. | |
618 | * | |
619 | * Since the ldisc state must represent the characters actually sent | |
620 | * to the driver at the time of the write, operations like certain | |
621 | * changes in column state are also saved in the buffer and executed | |
622 | * here. | |
623 | * | |
624 | * A circular fifo buffer is used so that the most recent characters | |
625 | * are prioritized. Also, when control characters are echoed with a | |
626 | * prefixed "^", the pair is treated atomically and thus not separated. | |
627 | * | |
019ebdf9 | 628 | * Locking: callers must hold output_lock |
a88a69c9 JP |
629 | */ |
630 | ||
bc5b1ec5 | 631 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 632 | { |
53c5ee2c | 633 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 634 | int space, old_space; |
addaebcc | 635 | size_t tail; |
a88a69c9 | 636 | unsigned char c; |
a88a69c9 | 637 | |
bc5b1ec5 | 638 | old_space = space = tty_write_room(tty); |
a88a69c9 | 639 | |
addaebcc | 640 | tail = ldata->echo_tail; |
29c7c5ca | 641 | while (ldata->echo_commit != tail) { |
addaebcc | 642 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
643 | if (c == ECHO_OP_START) { |
644 | unsigned char op; | |
a88a69c9 JP |
645 | int no_space_left = 0; |
646 | ||
647 | /* | |
648 | * If the buffer byte is the start of a multi-byte | |
649 | * operation, get the next byte, which is either the | |
650 | * op code or a control character value. | |
651 | */ | |
addaebcc | 652 | op = echo_buf(ldata, tail + 1); |
300a6204 | 653 | |
a88a69c9 JP |
654 | switch (op) { |
655 | unsigned int num_chars, num_bs; | |
656 | ||
657 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 658 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
659 | |
660 | /* | |
661 | * Determine how many columns to go back | |
662 | * in order to erase the tab. | |
663 | * This depends on the number of columns | |
664 | * used by other characters within the tab | |
665 | * area. If this (modulo 8) count is from | |
666 | * the start of input rather than from a | |
667 | * previous tab, we offset by canon column. | |
668 | * Otherwise, tab spacing is normal. | |
669 | */ | |
670 | if (!(num_chars & 0x80)) | |
ba2e68ac | 671 | num_chars += ldata->canon_column; |
a88a69c9 JP |
672 | num_bs = 8 - (num_chars & 7); |
673 | ||
674 | if (num_bs > space) { | |
675 | no_space_left = 1; | |
676 | break; | |
677 | } | |
678 | space -= num_bs; | |
679 | while (num_bs--) { | |
680 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
681 | if (ldata->column > 0) |
682 | ldata->column--; | |
a88a69c9 | 683 | } |
addaebcc | 684 | tail += 3; |
a88a69c9 JP |
685 | break; |
686 | ||
687 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 688 | ldata->canon_column = ldata->column; |
addaebcc | 689 | tail += 2; |
a88a69c9 JP |
690 | break; |
691 | ||
692 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
693 | if (ldata->column > 0) |
694 | ldata->column--; | |
addaebcc | 695 | tail += 2; |
a88a69c9 JP |
696 | break; |
697 | ||
698 | case ECHO_OP_START: | |
699 | /* This is an escaped echo op start code */ | |
700 | if (!space) { | |
701 | no_space_left = 1; | |
702 | break; | |
703 | } | |
704 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 705 | ldata->column++; |
a88a69c9 | 706 | space--; |
addaebcc | 707 | tail += 2; |
a88a69c9 JP |
708 | break; |
709 | ||
710 | default: | |
a88a69c9 | 711 | /* |
62b26358 JP |
712 | * If the op is not a special byte code, |
713 | * it is a ctrl char tagged to be echoed | |
714 | * as "^X" (where X is the letter | |
715 | * representing the control char). | |
716 | * Note that we must ensure there is | |
717 | * enough space for the whole ctrl pair. | |
718 | * | |
a88a69c9 | 719 | */ |
62b26358 JP |
720 | if (space < 2) { |
721 | no_space_left = 1; | |
722 | break; | |
723 | } | |
724 | tty_put_char(tty, '^'); | |
725 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 726 | ldata->column += 2; |
62b26358 | 727 | space -= 2; |
addaebcc | 728 | tail += 2; |
a88a69c9 JP |
729 | } |
730 | ||
731 | if (no_space_left) | |
732 | break; | |
733 | } else { | |
582f5590 | 734 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
735 | int retval = do_output_char(c, tty, space); |
736 | if (retval < 0) | |
737 | break; | |
738 | space -= retval; | |
739 | } else { | |
740 | if (!space) | |
741 | break; | |
742 | tty_put_char(tty, c); | |
743 | space -= 1; | |
744 | } | |
addaebcc | 745 | tail += 1; |
a88a69c9 | 746 | } |
a88a69c9 JP |
747 | } |
748 | ||
cbfd0340 PH |
749 | /* If the echo buffer is nearly full (so that the possibility exists |
750 | * of echo overrun before the next commit), then discard enough | |
751 | * data at the tail to prevent a subsequent overrun */ | |
752 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 753 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 754 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
755 | tail += 3; |
756 | else | |
757 | tail += 2; | |
758 | } else | |
759 | tail++; | |
760 | } | |
761 | ||
addaebcc | 762 | ldata->echo_tail = tail; |
bc5b1ec5 | 763 | return old_space - space; |
019ebdf9 PH |
764 | } |
765 | ||
766 | static void commit_echoes(struct tty_struct *tty) | |
767 | { | |
768 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 769 | size_t nr, old, echoed; |
cbfd0340 PH |
770 | size_t head; |
771 | ||
772 | head = ldata->echo_head; | |
1075a6e2 | 773 | ldata->echo_mark = head; |
cbfd0340 PH |
774 | old = ldata->echo_commit - ldata->echo_tail; |
775 | ||
776 | /* Process committed echoes if the accumulated # of bytes | |
777 | * is over the threshold (and try again each time another | |
778 | * block is accumulated) */ | |
779 | nr = head - ldata->echo_tail; | |
780 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
781 | return; | |
a88a69c9 | 782 | |
019ebdf9 | 783 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 784 | ldata->echo_commit = head; |
bc5b1ec5 | 785 | echoed = __process_echoes(tty); |
bddc7152 | 786 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 787 | |
bc5b1ec5 | 788 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
789 | tty->ops->flush_chars(tty); |
790 | } | |
791 | ||
019ebdf9 | 792 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
793 | { |
794 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 795 | size_t echoed; |
17bd7907 | 796 | |
e2613be5 | 797 | if (ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
798 | return; |
799 | ||
800 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 801 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 802 | echoed = __process_echoes(tty); |
019ebdf9 PH |
803 | mutex_unlock(&ldata->output_lock); |
804 | ||
bc5b1ec5 | 805 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 806 | tty->ops->flush_chars(tty); |
17bd7907 PH |
807 | } |
808 | ||
1075a6e2 | 809 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
810 | static void flush_echoes(struct tty_struct *tty) |
811 | { | |
812 | struct n_tty_data *ldata = tty->disc_data; | |
813 | ||
39434abd PH |
814 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
815 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
816 | return; |
817 | ||
818 | mutex_lock(&ldata->output_lock); | |
819 | ldata->echo_commit = ldata->echo_head; | |
820 | __process_echoes(tty); | |
821 | mutex_unlock(&ldata->output_lock); | |
822 | } | |
823 | ||
a88a69c9 JP |
824 | /** |
825 | * add_echo_byte - add a byte to the echo buffer | |
826 | * @c: unicode byte to echo | |
57c94121 | 827 | * @ldata: n_tty data |
a88a69c9 JP |
828 | * |
829 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
830 | */ |
831 | ||
cbfd0340 | 832 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 833 | { |
addaebcc | 834 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
835 | } |
836 | ||
837 | /** | |
838 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 839 | * @ldata: n_tty data |
a88a69c9 JP |
840 | * |
841 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
842 | */ |
843 | ||
57c94121 | 844 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 845 | { |
57c94121 JS |
846 | add_echo_byte(ECHO_OP_START, ldata); |
847 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
848 | } |
849 | ||
850 | /** | |
851 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 852 | * @ldata: n_tty data |
a88a69c9 JP |
853 | * |
854 | * Add an operation to the echo buffer to set the canon column | |
855 | * to the current column. | |
a88a69c9 JP |
856 | */ |
857 | ||
57c94121 | 858 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 859 | { |
57c94121 JS |
860 | add_echo_byte(ECHO_OP_START, ldata); |
861 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
862 | } |
863 | ||
864 | /** | |
865 | * echo_erase_tab - add operation to erase a tab | |
866 | * @num_chars: number of character columns already used | |
867 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 868 | * @ldata: n_tty data |
a88a69c9 JP |
869 | * |
870 | * Add an operation to the echo buffer to erase a tab. | |
871 | * | |
872 | * Called by the eraser function, which knows how many character | |
873 | * columns have been used since either a previous tab or the start | |
874 | * of input. This information will be used later, along with | |
875 | * canon column (if applicable), to go back the correct number | |
876 | * of columns. | |
a88a69c9 JP |
877 | */ |
878 | ||
879 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 880 | struct n_tty_data *ldata) |
a88a69c9 | 881 | { |
57c94121 JS |
882 | add_echo_byte(ECHO_OP_START, ldata); |
883 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
884 | |
885 | /* We only need to know this modulo 8 (tab spacing) */ | |
886 | num_chars &= 7; | |
887 | ||
888 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
889 | if (after_tab) | |
890 | num_chars |= 0x80; | |
300a6204 | 891 | |
57c94121 | 892 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
893 | } |
894 | ||
895 | /** | |
896 | * echo_char_raw - echo a character raw | |
897 | * @c: unicode byte to echo | |
898 | * @tty: terminal device | |
899 | * | |
900 | * Echo user input back onto the screen. This must be called only when | |
901 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
902 | * | |
903 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
904 | */ |
905 | ||
57c94121 | 906 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 907 | { |
a88a69c9 | 908 | if (c == ECHO_OP_START) { |
57c94121 JS |
909 | add_echo_byte(ECHO_OP_START, ldata); |
910 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 911 | } else { |
57c94121 | 912 | add_echo_byte(c, ldata); |
a88a69c9 | 913 | } |
a88a69c9 | 914 | } |
1da177e4 | 915 | |
1da177e4 | 916 | /** |
a88a69c9 | 917 | * echo_char - echo a character |
1da177e4 LT |
918 | * @c: unicode byte to echo |
919 | * @tty: terminal device | |
920 | * | |
4edf1827 | 921 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 922 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 923 | * |
62b26358 JP |
924 | * This variant tags control characters to be echoed as "^X" |
925 | * (where X is the letter representing the control char). | |
1da177e4 LT |
926 | */ |
927 | ||
928 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
929 | { | |
bddc7152 JS |
930 | struct n_tty_data *ldata = tty->disc_data; |
931 | ||
a88a69c9 | 932 | if (c == ECHO_OP_START) { |
57c94121 JS |
933 | add_echo_byte(ECHO_OP_START, ldata); |
934 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 935 | } else { |
62b26358 | 936 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
937 | add_echo_byte(ECHO_OP_START, ldata); |
938 | add_echo_byte(c, ldata); | |
a88a69c9 | 939 | } |
1da177e4 LT |
940 | } |
941 | ||
17b82060 | 942 | /** |
a88a69c9 | 943 | * finish_erasing - complete erase |
57c94121 | 944 | * @ldata: n_tty data |
17b82060 | 945 | */ |
a88a69c9 | 946 | |
57c94121 | 947 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 948 | { |
53c5ee2c | 949 | if (ldata->erasing) { |
57c94121 | 950 | echo_char_raw('/', ldata); |
53c5ee2c | 951 | ldata->erasing = 0; |
1da177e4 LT |
952 | } |
953 | } | |
954 | ||
955 | /** | |
956 | * eraser - handle erase function | |
957 | * @c: character input | |
958 | * @tty: terminal device | |
959 | * | |
3a4fa0a2 | 960 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
961 | * present in the stream from the driver layer. Handles the complexities |
962 | * of UTF-8 multibyte symbols. | |
17b82060 | 963 | * |
6d76bd26 PH |
964 | * n_tty_receive_buf()/producer path: |
965 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 966 | */ |
4edf1827 | 967 | |
1da177e4 LT |
968 | static void eraser(unsigned char c, struct tty_struct *tty) |
969 | { | |
53c5ee2c | 970 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 971 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
972 | size_t head; |
973 | size_t cnt; | |
974 | int seen_alnums; | |
1da177e4 | 975 | |
ba2e68ac | 976 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 977 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
978 | return; |
979 | } | |
980 | if (c == ERASE_CHAR(tty)) | |
981 | kill_type = ERASE; | |
982 | else if (c == WERASE_CHAR(tty)) | |
983 | kill_type = WERASE; | |
984 | else { | |
985 | if (!L_ECHO(tty)) { | |
ba2e68ac | 986 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
987 | return; |
988 | } | |
989 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 990 | ldata->read_head = ldata->canon_head; |
57c94121 | 991 | finish_erasing(ldata); |
1da177e4 LT |
992 | echo_char(KILL_CHAR(tty), tty); |
993 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
994 | if (L_ECHOK(tty)) | |
57c94121 | 995 | echo_char_raw('\n', ldata); |
1da177e4 LT |
996 | return; |
997 | } | |
998 | kill_type = KILL; | |
999 | } | |
1000 | ||
1001 | seen_alnums = 0; | |
ba2e68ac JS |
1002 | while (ldata->read_head != ldata->canon_head) { |
1003 | head = ldata->read_head; | |
1da177e4 LT |
1004 | |
1005 | /* erase a single possibly multibyte character */ | |
1006 | do { | |
bc5a5e3f PH |
1007 | head--; |
1008 | c = read_buf(ldata, head); | |
ba2e68ac | 1009 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1010 | |
1011 | /* do not partially erase */ | |
1012 | if (is_continuation(c, tty)) | |
1013 | break; | |
1014 | ||
1015 | if (kill_type == WERASE) { | |
1016 | /* Equivalent to BSD's ALTWERASE. */ | |
1017 | if (isalnum(c) || c == '_') | |
1018 | seen_alnums++; | |
1019 | else if (seen_alnums) | |
1020 | break; | |
1021 | } | |
bc5a5e3f | 1022 | cnt = ldata->read_head - head; |
ba2e68ac | 1023 | ldata->read_head = head; |
1da177e4 LT |
1024 | if (L_ECHO(tty)) { |
1025 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1026 | if (!ldata->erasing) { |
57c94121 | 1027 | echo_char_raw('\\', ldata); |
53c5ee2c | 1028 | ldata->erasing = 1; |
1da177e4 LT |
1029 | } |
1030 | /* if cnt > 1, output a multi-byte character */ | |
1031 | echo_char(c, tty); | |
1032 | while (--cnt > 0) { | |
bc5a5e3f PH |
1033 | head++; |
1034 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1035 | echo_move_back_col(ldata); |
1da177e4 LT |
1036 | } |
1037 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1038 | echo_char(ERASE_CHAR(tty), tty); | |
1039 | } else if (c == '\t') { | |
a88a69c9 JP |
1040 | unsigned int num_chars = 0; |
1041 | int after_tab = 0; | |
bc5a5e3f | 1042 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1043 | |
1044 | /* | |
1045 | * Count the columns used for characters | |
1046 | * since the start of input or after a | |
1047 | * previous tab. | |
1048 | * This info is used to go back the correct | |
1049 | * number of columns. | |
1050 | */ | |
ba2e68ac | 1051 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1052 | tail--; |
1053 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1054 | if (c == '\t') { |
1055 | after_tab = 1; | |
1056 | break; | |
300a6204 | 1057 | } else if (iscntrl(c)) { |
1da177e4 | 1058 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1059 | num_chars += 2; |
1060 | } else if (!is_continuation(c, tty)) { | |
1061 | num_chars++; | |
1062 | } | |
1da177e4 | 1063 | } |
57c94121 | 1064 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1065 | } else { |
1066 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1067 | echo_char_raw('\b', ldata); |
1068 | echo_char_raw(' ', ldata); | |
1069 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1070 | } |
1071 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1072 | echo_char_raw('\b', ldata); |
1073 | echo_char_raw(' ', ldata); | |
1074 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1075 | } |
1076 | } | |
1077 | } | |
1078 | if (kill_type == ERASE) | |
1079 | break; | |
1080 | } | |
ba2e68ac | 1081 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1082 | finish_erasing(ldata); |
1da177e4 LT |
1083 | } |
1084 | ||
1085 | /** | |
1086 | * isig - handle the ISIG optio | |
1087 | * @sig: signal | |
1088 | * @tty: terminal | |
1da177e4 | 1089 | * |
8c985d18 PH |
1090 | * Called when a signal is being sent due to terminal input. |
1091 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1092 | * |
8c985d18 | 1093 | * Locking: ctrl_lock |
1da177e4 | 1094 | */ |
4edf1827 | 1095 | |
4b293492 | 1096 | static void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1097 | { |
8c985d18 PH |
1098 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1099 | if (tty_pgrp) { | |
1100 | kill_pgrp(tty_pgrp, sig, 1); | |
1101 | put_pid(tty_pgrp); | |
1da177e4 LT |
1102 | } |
1103 | } | |
1104 | ||
1105 | /** | |
1106 | * n_tty_receive_break - handle break | |
1107 | * @tty: terminal | |
1108 | * | |
1109 | * An RS232 break event has been hit in the incoming bitstream. This | |
1110 | * can cause a variety of events depending upon the termios settings. | |
1111 | * | |
6d76bd26 PH |
1112 | * n_tty_receive_buf()/producer path: |
1113 | * caller holds non-exclusive termios_rwsem | |
6d76bd26 PH |
1114 | * |
1115 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1116 | */ |
4edf1827 | 1117 | |
4b293492 | 1118 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1119 | { |
57c94121 JS |
1120 | struct n_tty_data *ldata = tty->disc_data; |
1121 | ||
1da177e4 LT |
1122 | if (I_IGNBRK(tty)) |
1123 | return; | |
1124 | if (I_BRKINT(tty)) { | |
8c985d18 PH |
1125 | isig(SIGINT, tty); |
1126 | if (!L_NOFLSH(tty)) { | |
6d76bd26 PH |
1127 | /* flushing needs exclusive termios_rwsem */ |
1128 | up_read(&tty->termios_rwsem); | |
8c985d18 PH |
1129 | n_tty_flush_buffer(tty); |
1130 | tty_driver_flush_buffer(tty); | |
6d76bd26 | 1131 | down_read(&tty->termios_rwsem); |
8c985d18 | 1132 | } |
1da177e4 LT |
1133 | return; |
1134 | } | |
1135 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1136 | put_tty_queue('\377', ldata); |
1137 | put_tty_queue('\0', ldata); | |
1da177e4 | 1138 | } |
57c94121 | 1139 | put_tty_queue('\0', ldata); |
6c67716d | 1140 | if (waitqueue_active(&tty->read_wait)) |
57087d51 | 1141 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 LT |
1142 | } |
1143 | ||
1144 | /** | |
1145 | * n_tty_receive_overrun - handle overrun reporting | |
1146 | * @tty: terminal | |
1147 | * | |
1148 | * Data arrived faster than we could process it. While the tty | |
1149 | * driver has flagged this the bits that were missed are gone | |
1150 | * forever. | |
1151 | * | |
1152 | * Called from the receive_buf path so single threaded. Does not | |
1153 | * need locking as num_overrun and overrun_time are function | |
1154 | * private. | |
1155 | */ | |
4edf1827 | 1156 | |
4b293492 | 1157 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1158 | { |
53c5ee2c | 1159 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1160 | char buf[64]; |
1161 | ||
53c5ee2c JS |
1162 | ldata->num_overrun++; |
1163 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1164 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1165 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1166 | tty_name(tty, buf), | |
53c5ee2c JS |
1167 | ldata->num_overrun); |
1168 | ldata->overrun_time = jiffies; | |
1169 | ldata->num_overrun = 0; | |
1da177e4 LT |
1170 | } |
1171 | } | |
1172 | ||
1173 | /** | |
1174 | * n_tty_receive_parity_error - error notifier | |
1175 | * @tty: terminal device | |
1176 | * @c: character | |
1177 | * | |
1178 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1179 | * the error case if necessary. |
1180 | * | |
1181 | * n_tty_receive_buf()/producer path: | |
1182 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 1183 | */ |
4b293492 | 1184 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1185 | { |
57c94121 JS |
1186 | struct n_tty_data *ldata = tty->disc_data; |
1187 | ||
66528f90 PH |
1188 | if (I_INPCK(tty)) { |
1189 | if (I_IGNPAR(tty)) | |
1190 | return; | |
1191 | if (I_PARMRK(tty)) { | |
1192 | put_tty_queue('\377', ldata); | |
1193 | put_tty_queue('\0', ldata); | |
1194 | put_tty_queue(c, ldata); | |
1195 | } else | |
1196 | put_tty_queue('\0', ldata); | |
1197 | } else | |
57c94121 | 1198 | put_tty_queue(c, ldata); |
6c67716d | 1199 | if (waitqueue_active(&tty->read_wait)) |
57087d51 | 1200 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 LT |
1201 | } |
1202 | ||
b0ac50be PH |
1203 | static void |
1204 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1205 | { | |
1206 | if (!L_NOFLSH(tty)) { | |
1207 | /* flushing needs exclusive termios_rwsem */ | |
1208 | up_read(&tty->termios_rwsem); | |
1209 | n_tty_flush_buffer(tty); | |
1210 | tty_driver_flush_buffer(tty); | |
1211 | down_read(&tty->termios_rwsem); | |
1212 | } | |
1213 | if (I_IXON(tty)) | |
1214 | start_tty(tty); | |
1215 | if (L_ECHO(tty)) { | |
1216 | echo_char(c, tty); | |
1217 | commit_echoes(tty); | |
e2613be5 PH |
1218 | } else |
1219 | process_echoes(tty); | |
b0ac50be PH |
1220 | isig(signal, tty); |
1221 | return; | |
1222 | } | |
1223 | ||
1da177e4 LT |
1224 | /** |
1225 | * n_tty_receive_char - perform processing | |
1226 | * @tty: terminal device | |
1227 | * @c: character | |
1228 | * | |
1229 | * Process an individual character of input received from the driver. | |
4edf1827 | 1230 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1231 | * driver above. |
6d76bd26 PH |
1232 | * |
1233 | * n_tty_receive_buf()/producer path: | |
1234 | * caller holds non-exclusive termios_rwsem | |
1235 | * publishes canon_head if canonical mode is active | |
e60d27c4 PH |
1236 | * |
1237 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1238 | */ |
1239 | ||
e60d27c4 | 1240 | static int |
4b1f79c2 | 1241 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1242 | { |
53c5ee2c | 1243 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1244 | |
1da177e4 LT |
1245 | if (I_IXON(tty)) { |
1246 | if (c == START_CHAR(tty)) { | |
1247 | start_tty(tty); | |
e2613be5 | 1248 | process_echoes(tty); |
e60d27c4 | 1249 | return 0; |
1da177e4 LT |
1250 | } |
1251 | if (c == STOP_CHAR(tty)) { | |
1252 | stop_tty(tty); | |
e60d27c4 | 1253 | return 0; |
1da177e4 LT |
1254 | } |
1255 | } | |
575537b3 | 1256 | |
1da177e4 | 1257 | if (L_ISIG(tty)) { |
b0ac50be PH |
1258 | if (c == INTR_CHAR(tty)) { |
1259 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1260 | return 0; |
b0ac50be PH |
1261 | } else if (c == QUIT_CHAR(tty)) { |
1262 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1263 | return 0; |
b0ac50be PH |
1264 | } else if (c == SUSP_CHAR(tty)) { |
1265 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1266 | return 0; |
1da177e4 LT |
1267 | } |
1268 | } | |
575537b3 | 1269 | |
855df3c0 PH |
1270 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1271 | start_tty(tty); | |
1272 | process_echoes(tty); | |
1273 | } | |
1274 | ||
575537b3 JP |
1275 | if (c == '\r') { |
1276 | if (I_IGNCR(tty)) | |
e60d27c4 | 1277 | return 0; |
575537b3 JP |
1278 | if (I_ICRNL(tty)) |
1279 | c = '\n'; | |
1280 | } else if (c == '\n' && I_INLCR(tty)) | |
1281 | c = '\r'; | |
1282 | ||
53c5ee2c | 1283 | if (ldata->icanon) { |
1da177e4 LT |
1284 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1285 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1286 | eraser(c, tty); | |
17bd7907 | 1287 | commit_echoes(tty); |
e60d27c4 | 1288 | return 0; |
1da177e4 LT |
1289 | } |
1290 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1291 | ldata->lnext = 1; |
1da177e4 | 1292 | if (L_ECHO(tty)) { |
57c94121 | 1293 | finish_erasing(ldata); |
1da177e4 | 1294 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1295 | echo_char_raw('^', ldata); |
1296 | echo_char_raw('\b', ldata); | |
17bd7907 | 1297 | commit_echoes(tty); |
1da177e4 LT |
1298 | } |
1299 | } | |
e60d27c4 | 1300 | return 1; |
1da177e4 | 1301 | } |
e60d27c4 | 1302 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1303 | size_t tail = ldata->canon_head; |
1da177e4 | 1304 | |
57c94121 | 1305 | finish_erasing(ldata); |
1da177e4 | 1306 | echo_char(c, tty); |
57c94121 | 1307 | echo_char_raw('\n', ldata); |
ba2e68ac | 1308 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1309 | echo_char(read_buf(ldata, tail), tty); |
1310 | tail++; | |
1da177e4 | 1311 | } |
17bd7907 | 1312 | commit_echoes(tty); |
e60d27c4 | 1313 | return 0; |
1da177e4 LT |
1314 | } |
1315 | if (c == '\n') { | |
acc71bba | 1316 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1317 | echo_char_raw('\n', ldata); |
17bd7907 | 1318 | commit_echoes(tty); |
1da177e4 LT |
1319 | } |
1320 | goto handle_newline; | |
1321 | } | |
1322 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1323 | c = __DISABLED_CHAR; |
1324 | goto handle_newline; | |
1325 | } | |
1326 | if ((c == EOL_CHAR(tty)) || | |
1327 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1328 | /* | |
1329 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1330 | */ | |
1331 | if (L_ECHO(tty)) { | |
1da177e4 | 1332 | /* Record the column of first canon char. */ |
ba2e68ac | 1333 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1334 | echo_set_canon_col(ldata); |
1da177e4 | 1335 | echo_char(c, tty); |
17bd7907 | 1336 | commit_echoes(tty); |
1da177e4 LT |
1337 | } |
1338 | /* | |
1339 | * XXX does PARMRK doubling happen for | |
1340 | * EOL_CHAR and EOL2_CHAR? | |
1341 | */ | |
001ba923 | 1342 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
57c94121 | 1343 | put_tty_queue(c, ldata); |
1da177e4 | 1344 | |
4edf1827 | 1345 | handle_newline: |
bc5a5e3f | 1346 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1347 | put_tty_queue(c, ldata); |
70aca71f | 1348 | smp_store_release(&ldata->canon_head, ldata->read_head); |
1da177e4 LT |
1349 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1350 | if (waitqueue_active(&tty->read_wait)) | |
57087d51 | 1351 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
e60d27c4 | 1352 | return 0; |
1da177e4 LT |
1353 | } |
1354 | } | |
4edf1827 | 1355 | |
acc71bba | 1356 | if (L_ECHO(tty)) { |
57c94121 | 1357 | finish_erasing(ldata); |
1da177e4 | 1358 | if (c == '\n') |
57c94121 | 1359 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1360 | else { |
1361 | /* Record the column of first canon char. */ | |
ba2e68ac | 1362 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1363 | echo_set_canon_col(ldata); |
1da177e4 LT |
1364 | echo_char(c, tty); |
1365 | } | |
17bd7907 | 1366 | commit_echoes(tty); |
1da177e4 LT |
1367 | } |
1368 | ||
001ba923 PH |
1369 | /* PARMRK doubling check */ |
1370 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
57c94121 | 1371 | put_tty_queue(c, ldata); |
1da177e4 | 1372 | |
57c94121 | 1373 | put_tty_queue(c, ldata); |
e60d27c4 | 1374 | return 0; |
4edf1827 | 1375 | } |
1da177e4 | 1376 | |
e60d27c4 PH |
1377 | static inline void |
1378 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1379 | { |
1380 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1381 | |
e60d27c4 PH |
1382 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1383 | start_tty(tty); | |
1384 | process_echoes(tty); | |
1385 | } | |
1386 | if (L_ECHO(tty)) { | |
1387 | finish_erasing(ldata); | |
1388 | /* Record the column of first canon char. */ | |
1389 | if (ldata->canon_head == ldata->read_head) | |
1390 | echo_set_canon_col(ldata); | |
1391 | echo_char(c, tty); | |
1392 | commit_echoes(tty); | |
4b1f79c2 | 1393 | } |
001ba923 PH |
1394 | /* PARMRK doubling check */ |
1395 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
e60d27c4 PH |
1396 | put_tty_queue(c, ldata); |
1397 | put_tty_queue(c, ldata); | |
1398 | } | |
4b1f79c2 | 1399 | |
eb3e4668 | 1400 | static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
e60d27c4 PH |
1401 | { |
1402 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1403 | } |
1404 | ||
7de971b0 PH |
1405 | static inline void |
1406 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1407 | { | |
1408 | struct n_tty_data *ldata = tty->disc_data; | |
1409 | ||
e60d27c4 PH |
1410 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1411 | start_tty(tty); | |
1412 | process_echoes(tty); | |
7de971b0 | 1413 | } |
e60d27c4 PH |
1414 | if (L_ECHO(tty)) { |
1415 | finish_erasing(ldata); | |
1416 | /* Record the column of first canon char. */ | |
1417 | if (ldata->canon_head == ldata->read_head) | |
1418 | echo_set_canon_col(ldata); | |
1419 | echo_char(c, tty); | |
1420 | commit_echoes(tty); | |
1421 | } | |
1422 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1423 | } |
1424 | ||
8dc4b25d | 1425 | static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) |
ad0cc7ba PH |
1426 | { |
1427 | if (I_ISTRIP(tty)) | |
1428 | c &= 0x7f; | |
1429 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1430 | c = tolower(c); | |
1431 | ||
1432 | if (I_IXON(tty)) { | |
1433 | if (c == STOP_CHAR(tty)) | |
1434 | stop_tty(tty); | |
1435 | else if (c == START_CHAR(tty) || | |
1436 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1437 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1438 | c != SUSP_CHAR(tty))) { | |
1439 | start_tty(tty); | |
1440 | process_echoes(tty); | |
1441 | } | |
1442 | } | |
1443 | } | |
1444 | ||
d2f8d7ab PH |
1445 | static void |
1446 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1447 | { | |
1448 | char buf[64]; | |
1449 | ||
1450 | switch (flag) { | |
1451 | case TTY_BREAK: | |
1452 | n_tty_receive_break(tty); | |
1453 | break; | |
1454 | case TTY_PARITY: | |
1455 | case TTY_FRAME: | |
1456 | n_tty_receive_parity_error(tty, c); | |
1457 | break; | |
1458 | case TTY_OVERRUN: | |
1459 | n_tty_receive_overrun(tty); | |
1460 | break; | |
1461 | default: | |
1462 | printk(KERN_ERR "%s: unknown flag %d\n", | |
1463 | tty_name(tty, buf), flag); | |
1464 | break; | |
1465 | } | |
1466 | } | |
1467 | ||
e60d27c4 PH |
1468 | static void |
1469 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1470 | { | |
1471 | struct n_tty_data *ldata = tty->disc_data; | |
1472 | ||
1473 | ldata->lnext = 0; | |
1474 | if (likely(flag == TTY_NORMAL)) { | |
1475 | if (I_ISTRIP(tty)) | |
1476 | c &= 0x7f; | |
1477 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1478 | c = tolower(c); | |
1479 | n_tty_receive_char(tty, c); | |
1480 | } else | |
1481 | n_tty_receive_char_flagged(tty, c, flag); | |
1482 | } | |
1483 | ||
4a23a4df PH |
1484 | static void |
1485 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1486 | char *fp, int count) | |
1487 | { | |
1488 | struct n_tty_data *ldata = tty->disc_data; | |
1489 | size_t n, head; | |
1490 | ||
1491 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1492 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1493 | memcpy(read_buf_addr(ldata, head), cp, n); |
1494 | ldata->read_head += n; | |
1495 | cp += n; | |
1496 | count -= n; | |
1497 | ||
1498 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1499 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1500 | memcpy(read_buf_addr(ldata, head), cp, n); |
1501 | ldata->read_head += n; | |
1502 | } | |
1503 | ||
554117bd PH |
1504 | static void |
1505 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1506 | char *fp, int count) | |
1507 | { | |
1508 | struct n_tty_data *ldata = tty->disc_data; | |
1509 | char flag = TTY_NORMAL; | |
1510 | ||
1511 | while (count--) { | |
1512 | if (fp) | |
1513 | flag = *fp++; | |
1514 | if (likely(flag == TTY_NORMAL)) | |
1515 | put_tty_queue(*cp++, ldata); | |
1516 | else | |
1517 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1518 | } | |
1519 | } | |
1520 | ||
ad0cc7ba PH |
1521 | static void |
1522 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1523 | char *fp, int count) | |
1524 | { | |
1525 | char flag = TTY_NORMAL; | |
1526 | ||
1527 | while (count--) { | |
1528 | if (fp) | |
1529 | flag = *fp++; | |
1530 | if (likely(flag == TTY_NORMAL)) | |
1531 | n_tty_receive_char_closing(tty, *cp++); | |
1532 | else | |
1533 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1534 | } | |
1535 | } | |
1536 | ||
7d88d637 PH |
1537 | static void |
1538 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1539 | char *fp, int count) |
1540 | { | |
1541 | struct n_tty_data *ldata = tty->disc_data; | |
1542 | char flag = TTY_NORMAL; | |
1543 | ||
1544 | while (count--) { | |
1545 | if (fp) | |
1546 | flag = *fp++; | |
1547 | if (likely(flag == TTY_NORMAL)) { | |
1548 | unsigned char c = *cp++; | |
1549 | ||
1550 | if (I_ISTRIP(tty)) | |
1551 | c &= 0x7f; | |
1552 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1553 | c = tolower(c); | |
1554 | if (L_EXTPROC(tty)) { | |
1555 | put_tty_queue(c, ldata); | |
1556 | continue; | |
1557 | } | |
e60d27c4 PH |
1558 | if (!test_bit(c, ldata->char_map)) |
1559 | n_tty_receive_char_inline(tty, c); | |
1560 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1561 | if (fp) | |
1562 | flag = *fp++; | |
1563 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1564 | count--; | |
1565 | } | |
6baad008 PH |
1566 | } else |
1567 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1568 | } | |
1569 | } | |
1570 | ||
1571 | static void | |
1572 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1573 | char *fp, int count) | |
7d88d637 | 1574 | { |
e60d27c4 | 1575 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1576 | char flag = TTY_NORMAL; |
1577 | ||
1578 | while (count--) { | |
1579 | if (fp) | |
1580 | flag = *fp++; | |
e60d27c4 PH |
1581 | if (likely(flag == TTY_NORMAL)) { |
1582 | unsigned char c = *cp++; | |
1583 | ||
1584 | if (!test_bit(c, ldata->char_map)) | |
1585 | n_tty_receive_char_fast(tty, c); | |
1586 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1587 | if (fp) | |
1588 | flag = *fp++; | |
1589 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1590 | count--; | |
1591 | } | |
1592 | } else | |
7d88d637 PH |
1593 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1594 | } | |
1595 | } | |
1596 | ||
24a89d1c PH |
1597 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1598 | char *fp, int count) | |
1da177e4 | 1599 | { |
53c5ee2c | 1600 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1601 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1602 | |
4a23a4df PH |
1603 | if (ldata->real_raw) |
1604 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1605 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1606 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1607 | else if (tty->closing && !L_EXTPROC(tty)) |
1608 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1609 | else { |
e60d27c4 PH |
1610 | if (ldata->lnext) { |
1611 | char flag = TTY_NORMAL; | |
1612 | ||
1613 | if (fp) | |
1614 | flag = *fp++; | |
1615 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1616 | count--; | |
1617 | } | |
1618 | ||
7de971b0 | 1619 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1620 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1621 | else | |
1622 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1623 | |
1624 | flush_echoes(tty); | |
f34d7a5b AC |
1625 | if (tty->ops->flush_chars) |
1626 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1627 | } |
1628 | ||
70aca71f PH |
1629 | if (ldata->icanon && !L_EXTPROC(tty)) |
1630 | return; | |
1631 | ||
1632 | /* publish read_head to consumer */ | |
1633 | smp_store_release(&ldata->commit_head, ldata->read_head); | |
1634 | ||
1635 | if ((read_cnt(ldata) >= ldata->minimum_to_wake) || L_EXTPROC(tty)) { | |
1da177e4 LT |
1636 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1637 | if (waitqueue_active(&tty->read_wait)) | |
57087d51 | 1638 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 | 1639 | } |
1da177e4 LT |
1640 | } |
1641 | ||
fb5ef9e7 PH |
1642 | /** |
1643 | * n_tty_receive_buf_common - process input | |
1644 | * @tty: device to receive input | |
1645 | * @cp: input chars | |
1646 | * @fp: flags for each char (if NULL, all chars are TTY_NORMAL) | |
1647 | * @count: number of input chars in @cp | |
1648 | * | |
1649 | * Called by the terminal driver when a block of characters has | |
1650 | * been received. This function must be called from soft contexts | |
1651 | * not from interrupt context. The driver is responsible for making | |
1652 | * calls one at a time and in order (or using flush_to_ldisc) | |
1653 | * | |
1654 | * Returns the # of input chars from @cp which were processed. | |
1655 | * | |
1656 | * In canonical mode, the maximum line length is 4096 chars (including | |
1657 | * the line termination char); lines longer than 4096 chars are | |
1658 | * truncated. After 4095 chars, input data is still processed but | |
1659 | * not stored. Overflow processing ensures the tty can always | |
1660 | * receive more input until at least one line can be read. | |
1661 | * | |
1662 | * In non-canonical mode, the read buffer will only accept 4095 chars; | |
1663 | * this provides the necessary space for a newline char if the input | |
1664 | * mode is switched to canonical. | |
1665 | * | |
1666 | * Note it is possible for the read buffer to _contain_ 4096 chars | |
1667 | * in non-canonical mode: the read buffer could already contain the | |
1668 | * maximum canon line of 4096 chars when the mode is switched to | |
1669 | * non-canonical. | |
1670 | * | |
1671 | * n_tty_receive_buf()/producer path: | |
1672 | * claims non-exclusive termios_rwsem | |
1673 | * publishes commit_head or canon_head | |
1674 | */ | |
5c32d123 PH |
1675 | static int |
1676 | n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, | |
1677 | char *fp, int count, int flow) | |
24a89d1c PH |
1678 | { |
1679 | struct n_tty_data *ldata = tty->disc_data; | |
fb5ef9e7 | 1680 | int room, n, rcvd = 0, overflow; |
24a89d1c | 1681 | |
9356b535 PH |
1682 | down_read(&tty->termios_rwsem); |
1683 | ||
19e2ad6a | 1684 | while (1) { |
70aca71f | 1685 | /* |
06c49f9f PH |
1686 | * When PARMRK is set, each input char may take up to 3 chars |
1687 | * in the read buf; reduce the buffer space avail by 3x | |
70aca71f PH |
1688 | * |
1689 | * If we are doing input canonicalization, and there are no | |
1690 | * pending newlines, let characters through without limit, so | |
1691 | * that erase characters will be handled. Other excess | |
1692 | * characters will be beeped. | |
1693 | * | |
1694 | * paired with store in *_copy_from_read_buf() -- guarantees | |
1695 | * the consumer has loaded the data in read_buf up to the new | |
1696 | * read_tail (so this producer will not overwrite unread data) | |
1697 | */ | |
1698 | size_t tail = smp_load_acquire(&ldata->read_tail); | |
70aca71f | 1699 | |
fb5ef9e7 | 1700 | room = N_TTY_BUF_SIZE - (ldata->read_head - tail); |
70aca71f | 1701 | if (I_PARMRK(tty)) |
fb5ef9e7 PH |
1702 | room = (room + 2) / 3; |
1703 | room--; | |
1704 | if (room <= 0) { | |
1705 | overflow = ldata->icanon && ldata->canon_head == tail; | |
1706 | if (overflow && room < 0) | |
1707 | ldata->read_head--; | |
1708 | room = overflow; | |
1709 | ldata->no_room = flow && !room; | |
1710 | } else | |
1711 | overflow = 0; | |
70aca71f | 1712 | |
19e2ad6a | 1713 | n = min(count, room); |
fb5ef9e7 | 1714 | if (!n) |
19e2ad6a | 1715 | break; |
fb5ef9e7 PH |
1716 | |
1717 | /* ignore parity errors if handling overflow */ | |
1718 | if (!overflow || !fp || *fp != TTY_PARITY) | |
1719 | __receive_buf(tty, cp, fp, n); | |
1720 | ||
19e2ad6a PH |
1721 | cp += n; |
1722 | if (fp) | |
1723 | fp += n; | |
1724 | count -= n; | |
1725 | rcvd += n; | |
4a23a4df | 1726 | } |
24a89d1c | 1727 | |
19e2ad6a | 1728 | tty->receive_room = room; |
fb5ef9e7 PH |
1729 | |
1730 | /* Unthrottle if handling overflow on pty */ | |
1731 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { | |
1732 | if (overflow) { | |
1733 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1734 | tty_unthrottle_safe(tty); | |
1735 | __tty_set_flow_change(tty, 0); | |
1736 | } | |
1737 | } else | |
1738 | n_tty_check_throttle(tty); | |
1739 | ||
9356b535 PH |
1740 | up_read(&tty->termios_rwsem); |
1741 | ||
19e2ad6a | 1742 | return rcvd; |
24a89d1c PH |
1743 | } |
1744 | ||
5c32d123 PH |
1745 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1746 | char *fp, int count) | |
1747 | { | |
1748 | n_tty_receive_buf_common(tty, cp, fp, count, 0); | |
1749 | } | |
1750 | ||
1751 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1752 | char *fp, int count) | |
1753 | { | |
1754 | return n_tty_receive_buf_common(tty, cp, fp, count, 1); | |
1755 | } | |
1756 | ||
1da177e4 LT |
1757 | int is_ignored(int sig) |
1758 | { | |
1759 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1760 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1761 | } |
1762 | ||
1763 | /** | |
1764 | * n_tty_set_termios - termios data changed | |
1765 | * @tty: terminal | |
1766 | * @old: previous data | |
1767 | * | |
1768 | * Called by the tty layer when the user changes termios flags so | |
1769 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1770 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1771 | * guaranteed that this function will not be re-entered or in progress |
1772 | * when the ldisc is closed. | |
17b82060 | 1773 | * |
6a1c0680 | 1774 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1775 | */ |
4edf1827 AC |
1776 | |
1777 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1778 | { |
53c5ee2c | 1779 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1780 | |
c786f74e | 1781 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { |
3fe780b3 | 1782 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1783 | ldata->line_start = ldata->read_tail; |
1784 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1785 | ldata->canon_head = ldata->read_tail; | |
1786 | ldata->push = 0; | |
1787 | } else { | |
1788 | set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), | |
1789 | ldata->read_flags); | |
1790 | ldata->canon_head = ldata->read_head; | |
1791 | ldata->push = 1; | |
1792 | } | |
70aca71f | 1793 | ldata->commit_head = ldata->read_head; |
53c5ee2c | 1794 | ldata->erasing = 0; |
6f9b028a | 1795 | ldata->lnext = 0; |
47afa7a5 AC |
1796 | } |
1797 | ||
53c5ee2c | 1798 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1799 | |
1da177e4 LT |
1800 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1801 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1802 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1803 | I_PARMRK(tty)) { | |
1bb9d562 | 1804 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1805 | |
1806 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1807 | set_bit('\r', ldata->char_map); |
1da177e4 | 1808 | if (I_INLCR(tty)) |
1bb9d562 | 1809 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1810 | |
1811 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1812 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1813 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1814 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1815 | set_bit('\n', ldata->char_map); | |
1816 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1817 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1818 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1819 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1820 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1821 | if (L_ECHO(tty)) |
1822 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1823 | ldata->char_map); |
1da177e4 LT |
1824 | } |
1825 | } | |
1826 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1827 | set_bit(START_CHAR(tty), ldata->char_map); |
1828 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1829 | } |
1830 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1831 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1832 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1833 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1834 | } |
1bb9d562 | 1835 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1836 | ldata->raw = 0; |
1837 | ldata->real_raw = 0; | |
1da177e4 | 1838 | } else { |
53c5ee2c | 1839 | ldata->raw = 1; |
1da177e4 LT |
1840 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1841 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1842 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1843 | ldata->real_raw = 1; |
1da177e4 | 1844 | else |
53c5ee2c | 1845 | ldata->real_raw = 0; |
1da177e4 | 1846 | } |
dab73b4e WY |
1847 | /* |
1848 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1849 | * been stopped by STOP_CHAR(tty) before it. | |
1850 | */ | |
e2613be5 | 1851 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { |
dab73b4e | 1852 | start_tty(tty); |
e2613be5 PH |
1853 | process_echoes(tty); |
1854 | } | |
dab73b4e | 1855 | |
f34d7a5b | 1856 | /* The termios change make the tty ready for I/O */ |
6c67716d PH |
1857 | if (waitqueue_active(&tty->write_wait)) |
1858 | wake_up_interruptible(&tty->write_wait); | |
1859 | if (waitqueue_active(&tty->read_wait)) | |
1860 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1861 | } |
1862 | ||
1863 | /** | |
1864 | * n_tty_close - close the ldisc for this tty | |
1865 | * @tty: device | |
1866 | * | |
4edf1827 AC |
1867 | * Called from the terminal layer when this line discipline is |
1868 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1869 | * discipline change. The function will not be called while other |
1870 | * ldisc methods are in progress. | |
1871 | */ | |
4edf1827 | 1872 | |
1da177e4 LT |
1873 | static void n_tty_close(struct tty_struct *tty) |
1874 | { | |
70ece7a7 JS |
1875 | struct n_tty_data *ldata = tty->disc_data; |
1876 | ||
79901317 PH |
1877 | if (tty->link) |
1878 | n_tty_packet_mode_flush(tty); | |
1879 | ||
20bafb3d | 1880 | vfree(ldata); |
70ece7a7 | 1881 | tty->disc_data = NULL; |
1da177e4 LT |
1882 | } |
1883 | ||
1884 | /** | |
1885 | * n_tty_open - open an ldisc | |
1886 | * @tty: terminal to open | |
1887 | * | |
4edf1827 | 1888 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1889 | * terminal device. Can sleep. Called serialized so that no |
1890 | * other events will occur in parallel. No further open will occur | |
1891 | * until a close. | |
1892 | */ | |
1893 | ||
1894 | static int n_tty_open(struct tty_struct *tty) | |
1895 | { | |
70ece7a7 JS |
1896 | struct n_tty_data *ldata; |
1897 | ||
20bafb3d PH |
1898 | /* Currently a malloc failure here can panic */ |
1899 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1900 | if (!ldata) |
1901 | goto err; | |
1902 | ||
53c5ee2c | 1903 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1904 | mutex_init(&ldata->atomic_read_lock); |
1905 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1906 | |
70ece7a7 | 1907 | tty->disc_data = ldata; |
b66f4fa5 | 1908 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1909 | ldata->column = 0; |
20bafb3d | 1910 | ldata->canon_column = 0; |
f6c8dbe6 | 1911 | ldata->minimum_to_wake = 1; |
20bafb3d PH |
1912 | ldata->num_overrun = 0; |
1913 | ldata->no_room = 0; | |
1914 | ldata->lnext = 0; | |
1da177e4 | 1915 | tty->closing = 0; |
b66f4fa5 PH |
1916 | /* indicate buffer work may resume */ |
1917 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1918 | n_tty_set_termios(tty, NULL); | |
1919 | tty_unthrottle(tty); | |
70ece7a7 | 1920 | |
1da177e4 | 1921 | return 0; |
70ece7a7 | 1922 | err: |
b91939f5 | 1923 | return -ENOMEM; |
1da177e4 LT |
1924 | } |
1925 | ||
eafbe67f | 1926 | static inline int input_available_p(struct tty_struct *tty, int poll) |
1da177e4 | 1927 | { |
53c5ee2c | 1928 | struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1929 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1930 | |
25e8d0ed PH |
1931 | if (ldata->icanon && !L_EXTPROC(tty)) |
1932 | return ldata->canon_head != ldata->read_tail; | |
1933 | else | |
70aca71f | 1934 | return ldata->commit_head - ldata->read_tail >= amt; |
1da177e4 LT |
1935 | } |
1936 | ||
1937 | /** | |
bbd20759 | 1938 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1939 | * @tty: terminal device |
1940 | * @b: user data | |
1941 | * @nr: size of data | |
1942 | * | |
11a96d18 | 1943 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1944 | * ICANON is off; it copies characters straight from the tty queue to |
1945 | * user space directly. It can be profitably called twice; once to | |
1946 | * drain the space from the tail pointer to the (physical) end of the | |
1947 | * buffer, and once to drain the space from the (physical) beginning of | |
1948 | * the buffer to head pointer. | |
1949 | * | |
bddc7152 | 1950 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1951 | * |
6d76bd26 PH |
1952 | * n_tty_read()/consumer path: |
1953 | * caller holds non-exclusive termios_rwsem | |
1954 | * read_tail published | |
1da177e4 | 1955 | */ |
4edf1827 | 1956 | |
33f0f88f | 1957 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1958 | unsigned char __user **b, |
1959 | size_t *nr) | |
1960 | ||
1961 | { | |
53c5ee2c | 1962 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1963 | int retval; |
1964 | size_t n; | |
3fa10cc8 | 1965 | bool is_eof; |
70aca71f | 1966 | size_t head = smp_load_acquire(&ldata->commit_head); |
bc5a5e3f | 1967 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1968 | |
1969 | retval = 0; | |
70aca71f | 1970 | n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail); |
1da177e4 | 1971 | n = min(*nr, n); |
1da177e4 | 1972 | if (n) { |
bc5a5e3f | 1973 | retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
1da177e4 | 1974 | n -= retval; |
bc5a5e3f PH |
1975 | is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); |
1976 | tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, | |
53c5ee2c | 1977 | ldata->icanon); |
70aca71f | 1978 | smp_store_release(&ldata->read_tail, ldata->read_tail + n); |
26df6d13 | 1979 | /* Turn single EOF into zero-length read */ |
70aca71f PH |
1980 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && |
1981 | (head == ldata->read_tail)) | |
3fa10cc8 | 1982 | n = 0; |
1da177e4 LT |
1983 | *b += n; |
1984 | *nr -= n; | |
1985 | } | |
1986 | return retval; | |
1987 | } | |
1988 | ||
88bb0de3 | 1989 | /** |
32f13521 | 1990 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1991 | * @tty: terminal device |
1992 | * @b: user data | |
1993 | * @nr: size of data | |
1994 | * | |
1995 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1996 | * it copies one line of input up to and including the line-delimiting |
1997 | * character into the user-space buffer. | |
88bb0de3 | 1998 | * |
4d0ed182 PH |
1999 | * NB: When termios is changed from non-canonical to canonical mode and |
2000 | * the read buffer contains data, n_tty_set_termios() simulates an EOF | |
2001 | * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. | |
2002 | * This causes data already processed as input to be immediately available | |
2003 | * as input although a newline has not been received. | |
2004 | * | |
88bb0de3 | 2005 | * Called under the atomic_read_lock mutex |
6d76bd26 PH |
2006 | * |
2007 | * n_tty_read()/consumer path: | |
2008 | * caller holds non-exclusive termios_rwsem | |
2009 | * read_tail published | |
88bb0de3 PH |
2010 | */ |
2011 | ||
32f13521 PH |
2012 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
2013 | unsigned char __user **b, | |
2014 | size_t *nr) | |
88bb0de3 PH |
2015 | { |
2016 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 2017 | size_t n, size, more, c; |
bc5a5e3f PH |
2018 | size_t eol; |
2019 | size_t tail; | |
2020 | int ret, found = 0; | |
40d5e090 | 2021 | bool eof_push = 0; |
88bb0de3 PH |
2022 | |
2023 | /* N.B. avoid overrun if nr == 0 */ | |
70aca71f | 2024 | n = min(*nr, smp_load_acquire(&ldata->canon_head) - ldata->read_tail); |
6d76bd26 | 2025 | if (!n) |
32f13521 | 2026 | return 0; |
88bb0de3 | 2027 | |
bc5a5e3f | 2028 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
2029 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
2030 | ||
bc5a5e3f | 2031 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2032 | __func__, *nr, tail, n, size); |
2033 | ||
2034 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2035 | more = n - (size - tail); | |
2036 | if (eol == N_TTY_BUF_SIZE && more) { | |
2037 | /* scan wrapped without finding set bit */ | |
2038 | eol = find_next_bit(ldata->read_flags, more, 0); | |
2039 | if (eol != more) | |
2040 | found = 1; | |
2041 | } else if (eol != size) | |
2042 | found = 1; | |
2043 | ||
2044 | size = N_TTY_BUF_SIZE - tail; | |
c77569d2 PH |
2045 | n = eol - tail; |
2046 | if (n > 4096) | |
2047 | n += 4096; | |
2048 | n += found; | |
32f13521 PH |
2049 | c = n; |
2050 | ||
4d0ed182 | 2051 | if (found && !ldata->push && read_buf(ldata, eol) == __DISABLED_CHAR) { |
32f13521 | 2052 | n--; |
40d5e090 PH |
2053 | eof_push = !n && ldata->read_tail != ldata->line_start; |
2054 | } | |
32f13521 | 2055 | |
bc5a5e3f | 2056 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", |
32f13521 PH |
2057 | __func__, eol, found, n, c, size, more); |
2058 | ||
32f13521 | 2059 | if (n > size) { |
bc5a5e3f | 2060 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), size); |
32f13521 PH |
2061 | if (ret) |
2062 | return -EFAULT; | |
2063 | ret = copy_to_user(*b + size, ldata->read_buf, n - size); | |
2064 | } else | |
bc5a5e3f | 2065 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
32f13521 PH |
2066 | |
2067 | if (ret) | |
2068 | return -EFAULT; | |
2069 | *b += n; | |
2070 | *nr -= n; | |
2071 | ||
a73d3d69 | 2072 | if (found) |
6d76bd26 | 2073 | clear_bit(eol, ldata->read_flags); |
70aca71f | 2074 | smp_store_release(&ldata->read_tail, ldata->read_tail + c); |
88bb0de3 | 2075 | |
40d5e090 | 2076 | if (found) { |
4d0ed182 PH |
2077 | if (!ldata->push) |
2078 | ldata->line_start = ldata->read_tail; | |
2079 | else | |
2080 | ldata->push = 0; | |
32f13521 | 2081 | tty_audit_push(tty); |
40d5e090 PH |
2082 | } |
2083 | return eof_push ? -EAGAIN : 0; | |
88bb0de3 PH |
2084 | } |
2085 | ||
cc4191dc | 2086 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2087 | size_t, loff_t *); |
1da177e4 LT |
2088 | |
2089 | /** | |
2090 | * job_control - check job control | |
2091 | * @tty: tty | |
2092 | * @file: file handle | |
2093 | * | |
2094 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2095 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2096 | * error code if action should be taken. |
04f378b1 | 2097 | * |
01a5e440 PH |
2098 | * Locking: redirected write test is safe |
2099 | * current->signal->tty check is safe | |
2100 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2101 | */ |
4edf1827 | 2102 | |
1da177e4 LT |
2103 | static int job_control(struct tty_struct *tty, struct file *file) |
2104 | { | |
2105 | /* Job control check -- must be done at start and after | |
2106 | every sleep (POSIX.1 7.1.1.4). */ | |
2107 | /* NOTE: not yet done after every sleep pending a thorough | |
2108 | check of the logic of this change. -- jlc */ | |
2109 | /* don't stop on /dev/console */ | |
01a5e440 PH |
2110 | if (file->f_op->write == redirected_tty_write || |
2111 | current->signal->tty != tty) | |
2112 | return 0; | |
2113 | ||
2114 | spin_lock_irq(&tty->ctrl_lock); | |
2115 | if (!tty->pgrp) | |
2116 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
2117 | else if (task_pgrp(current) != tty->pgrp) { | |
2118 | spin_unlock_irq(&tty->ctrl_lock); | |
2119 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
2120 | return -EIO; | |
2121 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
2122 | set_thread_flag(TIF_SIGPENDING); | |
2123 | return -ERESTARTSYS; | |
1da177e4 | 2124 | } |
01a5e440 | 2125 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
2126 | return 0; |
2127 | } | |
4edf1827 | 2128 | |
1da177e4 LT |
2129 | |
2130 | /** | |
11a96d18 | 2131 | * n_tty_read - read function for tty |
1da177e4 LT |
2132 | * @tty: tty device |
2133 | * @file: file object | |
2134 | * @buf: userspace buffer pointer | |
2135 | * @nr: size of I/O | |
2136 | * | |
2137 | * Perform reads for the line discipline. We are guaranteed that the | |
2138 | * line discipline will not be closed under us but we may get multiple | |
2139 | * parallel readers and must handle this ourselves. We may also get | |
2140 | * a hangup. Always called in user context, may sleep. | |
2141 | * | |
2142 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2143 | * |
2144 | * n_tty_read()/consumer path: | |
2145 | * claims non-exclusive termios_rwsem | |
2146 | * publishes read_tail | |
1da177e4 | 2147 | */ |
4edf1827 | 2148 | |
11a96d18 | 2149 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2150 | unsigned char __user *buf, size_t nr) |
2151 | { | |
53c5ee2c | 2152 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 2153 | unsigned char __user *b = buf; |
97d9e28d | 2154 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2155 | int c; |
2156 | int minimum, time; | |
2157 | ssize_t retval = 0; | |
1da177e4 | 2158 | long timeout; |
04f378b1 | 2159 | int packet; |
2c5dc464 | 2160 | size_t tail; |
1da177e4 | 2161 | |
1da177e4 | 2162 | c = job_control(tty, file); |
4edf1827 | 2163 | if (c < 0) |
1da177e4 | 2164 | return c; |
4edf1827 | 2165 | |
aefceaf4 PH |
2166 | /* |
2167 | * Internal serialization of reads. | |
2168 | */ | |
2169 | if (file->f_flags & O_NONBLOCK) { | |
2170 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2171 | return -EAGAIN; | |
2172 | } else { | |
2173 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2174 | return -ERESTARTSYS; | |
2175 | } | |
2176 | ||
9356b535 PH |
2177 | down_read(&tty->termios_rwsem); |
2178 | ||
1da177e4 LT |
2179 | minimum = time = 0; |
2180 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2181 | if (!ldata->icanon) { |
1da177e4 LT |
2182 | minimum = MIN_CHAR(tty); |
2183 | if (minimum) { | |
a6e54319 | 2184 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2185 | if (time) |
f6c8dbe6 | 2186 | ldata->minimum_to_wake = 1; |
1da177e4 | 2187 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
2188 | (ldata->minimum_to_wake > minimum)) |
2189 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 2190 | } else { |
a6e54319 | 2191 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2192 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2193 | } |
2194 | } | |
2195 | ||
04f378b1 | 2196 | packet = tty->packet; |
2c5dc464 | 2197 | tail = ldata->read_tail; |
1da177e4 LT |
2198 | |
2199 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2200 | while (nr) { |
2201 | /* First test for status change. */ | |
04f378b1 | 2202 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2203 | unsigned char cs; |
2204 | if (b != buf) | |
2205 | break; | |
6054c16e | 2206 | spin_lock_irq(&tty->link->ctrl_lock); |
1da177e4 LT |
2207 | cs = tty->link->ctrl_status; |
2208 | tty->link->ctrl_status = 0; | |
6054c16e | 2209 | spin_unlock_irq(&tty->link->ctrl_lock); |
522ed776 | 2210 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2211 | retval = -EFAULT; |
2212 | b--; | |
2213 | break; | |
2214 | } | |
2215 | nr--; | |
2216 | break; | |
2217 | } | |
4edf1827 | 2218 | |
f6c8dbe6 | 2219 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2220 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2221 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2222 | |
1da177e4 LT |
2223 | if (!input_available_p(tty, 0)) { |
2224 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
52bce7f8 PH |
2225 | retval = -EIO; |
2226 | break; | |
f8747d4a | 2227 | } |
52bce7f8 PH |
2228 | if (tty_hung_up_p(file)) |
2229 | break; | |
2230 | if (!timeout) | |
2231 | break; | |
2232 | if (file->f_flags & O_NONBLOCK) { | |
2233 | retval = -EAGAIN; | |
1da177e4 LT |
2234 | break; |
2235 | } | |
52bce7f8 PH |
2236 | if (signal_pending(current)) { |
2237 | retval = -ERESTARTSYS; | |
2238 | break; | |
2239 | } | |
52bce7f8 | 2240 | up_read(&tty->termios_rwsem); |
9356b535 | 2241 | |
37da7bbb LT |
2242 | timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, |
2243 | timeout); | |
9356b535 | 2244 | |
52bce7f8 PH |
2245 | down_read(&tty->termios_rwsem); |
2246 | continue; | |
1da177e4 LT |
2247 | } |
2248 | ||
53c5ee2c | 2249 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2250 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
40d5e090 PH |
2251 | if (retval == -EAGAIN) { |
2252 | retval = 0; | |
2253 | continue; | |
2254 | } else if (retval) | |
1da177e4 LT |
2255 | break; |
2256 | } else { | |
2257 | int uncopied; | |
95ea90db PH |
2258 | |
2259 | /* Deal with packet mode. */ | |
2260 | if (packet && b == buf) { | |
2261 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { | |
2262 | retval = -EFAULT; | |
2263 | b--; | |
2264 | break; | |
2265 | } | |
2266 | nr--; | |
2267 | } | |
2268 | ||
1da177e4 LT |
2269 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2270 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2271 | if (uncopied) { | |
2272 | retval = -EFAULT; | |
2273 | break; | |
2274 | } | |
2275 | } | |
2276 | ||
6367ca72 | 2277 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2278 | |
2279 | if (b - buf >= minimum) | |
2280 | break; | |
2281 | if (time) | |
2282 | timeout = time; | |
2283 | } | |
2c5dc464 PH |
2284 | if (tail != ldata->read_tail) |
2285 | n_tty_kick_worker(tty); | |
42458f41 PH |
2286 | up_read(&tty->termios_rwsem); |
2287 | ||
1da177e4 | 2288 | remove_wait_queue(&tty->read_wait, &wait); |
1da177e4 | 2289 | if (!waitqueue_active(&tty->read_wait)) |
f6c8dbe6 | 2290 | ldata->minimum_to_wake = minimum; |
1da177e4 | 2291 | |
aebf0453 PH |
2292 | mutex_unlock(&ldata->atomic_read_lock); |
2293 | ||
40d5e090 PH |
2294 | if (b - buf) |
2295 | retval = b - buf; | |
1da177e4 LT |
2296 | |
2297 | return retval; | |
2298 | } | |
2299 | ||
2300 | /** | |
11a96d18 | 2301 | * n_tty_write - write function for tty |
1da177e4 LT |
2302 | * @tty: tty device |
2303 | * @file: file object | |
2304 | * @buf: userspace buffer pointer | |
2305 | * @nr: size of I/O | |
2306 | * | |
a88a69c9 | 2307 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2308 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2309 | * and other such events. Since the receive code will echo characters, |
2310 | * thus calling driver write methods, the output_lock is used in | |
2311 | * the output processing functions called here as well as in the | |
2312 | * echo processing function to protect the column state and space | |
2313 | * left in the buffer. | |
1da177e4 LT |
2314 | * |
2315 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2316 | * |
2317 | * Locking: output_lock to protect column state and space left | |
2318 | * (note that the process_output*() functions take this | |
2319 | * lock themselves) | |
1da177e4 | 2320 | */ |
4edf1827 | 2321 | |
11a96d18 | 2322 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2323 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2324 | { |
2325 | const unsigned char *b = buf; | |
97d9e28d | 2326 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2327 | int c; |
2328 | ssize_t retval = 0; | |
2329 | ||
2330 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2331 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2332 | retval = tty_check_change(tty); | |
2333 | if (retval) | |
2334 | return retval; | |
2335 | } | |
2336 | ||
9356b535 PH |
2337 | down_read(&tty->termios_rwsem); |
2338 | ||
a88a69c9 JP |
2339 | /* Write out any echoed characters that are still pending */ |
2340 | process_echoes(tty); | |
300a6204 | 2341 | |
1da177e4 LT |
2342 | add_wait_queue(&tty->write_wait, &wait); |
2343 | while (1) { | |
1da177e4 LT |
2344 | if (signal_pending(current)) { |
2345 | retval = -ERESTARTSYS; | |
2346 | break; | |
2347 | } | |
2348 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2349 | retval = -EIO; | |
2350 | break; | |
2351 | } | |
582f5590 | 2352 | if (O_OPOST(tty)) { |
1da177e4 | 2353 | while (nr > 0) { |
a88a69c9 | 2354 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2355 | if (num < 0) { |
2356 | if (num == -EAGAIN) | |
2357 | break; | |
2358 | retval = num; | |
2359 | goto break_out; | |
2360 | } | |
2361 | b += num; | |
2362 | nr -= num; | |
2363 | if (nr == 0) | |
2364 | break; | |
2365 | c = *b; | |
a88a69c9 | 2366 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2367 | break; |
2368 | b++; nr--; | |
2369 | } | |
f34d7a5b AC |
2370 | if (tty->ops->flush_chars) |
2371 | tty->ops->flush_chars(tty); | |
1da177e4 | 2372 | } else { |
4291086b PH |
2373 | struct n_tty_data *ldata = tty->disc_data; |
2374 | ||
d6afe27b | 2375 | while (nr > 0) { |
4291086b | 2376 | mutex_lock(&ldata->output_lock); |
f34d7a5b | 2377 | c = tty->ops->write(tty, b, nr); |
4291086b | 2378 | mutex_unlock(&ldata->output_lock); |
d6afe27b RZ |
2379 | if (c < 0) { |
2380 | retval = c; | |
2381 | goto break_out; | |
2382 | } | |
2383 | if (!c) | |
2384 | break; | |
2385 | b += c; | |
2386 | nr -= c; | |
1da177e4 | 2387 | } |
1da177e4 LT |
2388 | } |
2389 | if (!nr) | |
2390 | break; | |
2391 | if (file->f_flags & O_NONBLOCK) { | |
2392 | retval = -EAGAIN; | |
2393 | break; | |
2394 | } | |
9356b535 PH |
2395 | up_read(&tty->termios_rwsem); |
2396 | ||
97d9e28d | 2397 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
9356b535 PH |
2398 | |
2399 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2400 | } |
2401 | break_out: | |
1da177e4 | 2402 | remove_wait_queue(&tty->write_wait, &wait); |
ff8cb0fd TP |
2403 | if (b - buf != nr && tty->fasync) |
2404 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2405 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2406 | return (b - buf) ? b - buf : retval; |
2407 | } | |
2408 | ||
2409 | /** | |
11a96d18 | 2410 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2411 | * @tty: terminal device |
2412 | * @file: file accessing it | |
2413 | * @wait: poll table | |
2414 | * | |
2415 | * Called when the line discipline is asked to poll() for data or | |
2416 | * for special events. This code is not serialized with respect to | |
2417 | * other events save open/close. | |
2418 | * | |
2419 | * This code must be sure never to sleep through a hangup. | |
2420 | * Called without the kernel lock held - fine | |
1da177e4 | 2421 | */ |
4edf1827 | 2422 | |
11a96d18 | 2423 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2424 | poll_table *wait) |
1da177e4 | 2425 | { |
f6c8dbe6 | 2426 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2427 | unsigned int mask = 0; |
2428 | ||
2429 | poll_wait(file, &tty->read_wait, wait); | |
2430 | poll_wait(file, &tty->write_wait, wait); | |
eafbe67f | 2431 | if (input_available_p(tty, 1)) |
1da177e4 LT |
2432 | mask |= POLLIN | POLLRDNORM; |
2433 | if (tty->packet && tty->link->ctrl_status) | |
2434 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2ce3c10c PH |
2435 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) |
2436 | mask |= POLLHUP; | |
1da177e4 LT |
2437 | if (tty_hung_up_p(file)) |
2438 | mask |= POLLHUP; | |
2439 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2440 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2441 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2442 | else |
f6c8dbe6 | 2443 | ldata->minimum_to_wake = 1; |
1da177e4 | 2444 | } |
f34d7a5b AC |
2445 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2446 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2447 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2448 | mask |= POLLOUT | POLLWRNORM; |
2449 | return mask; | |
2450 | } | |
2451 | ||
57c94121 | 2452 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2453 | { |
bc5a5e3f | 2454 | size_t nr, head, tail; |
47afa7a5 | 2455 | |
a73d3d69 | 2456 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2457 | return 0; |
ba2e68ac JS |
2458 | head = ldata->canon_head; |
2459 | tail = ldata->read_tail; | |
bc5a5e3f | 2460 | nr = head - tail; |
47afa7a5 AC |
2461 | /* Skip EOF-chars.. */ |
2462 | while (head != tail) { | |
bc5a5e3f PH |
2463 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2464 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2465 | nr--; |
bc5a5e3f | 2466 | tail++; |
47afa7a5 AC |
2467 | } |
2468 | return nr; | |
2469 | } | |
2470 | ||
2471 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2472 | unsigned int cmd, unsigned long arg) | |
2473 | { | |
ba2e68ac | 2474 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2475 | int retval; |
2476 | ||
2477 | switch (cmd) { | |
2478 | case TIOCOUTQ: | |
2479 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2480 | case TIOCINQ: | |
6d76bd26 | 2481 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2482 | if (L_ICANON(tty)) |
57c94121 | 2483 | retval = inq_canon(ldata); |
6d76bd26 PH |
2484 | else |
2485 | retval = read_cnt(ldata); | |
2486 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2487 | return put_user(retval, (unsigned int __user *) arg); |
2488 | default: | |
2489 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2490 | } | |
2491 | } | |
2492 | ||
f6c8dbe6 PH |
2493 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2494 | { | |
2495 | struct n_tty_data *ldata = tty->disc_data; | |
2496 | ||
2497 | if (!waitqueue_active(&tty->read_wait)) { | |
2498 | if (on) | |
2499 | ldata->minimum_to_wake = 1; | |
2500 | else if (!tty->fasync) | |
2501 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2502 | } | |
2503 | } | |
2504 | ||
a352def2 | 2505 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2506 | .magic = TTY_LDISC_MAGIC, |
2507 | .name = "n_tty", | |
2508 | .open = n_tty_open, | |
2509 | .close = n_tty_close, | |
2510 | .flush_buffer = n_tty_flush_buffer, | |
2511 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2512 | .read = n_tty_read, |
2513 | .write = n_tty_write, | |
e10cc1df PF |
2514 | .ioctl = n_tty_ioctl, |
2515 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2516 | .poll = n_tty_poll, |
e10cc1df | 2517 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2518 | .write_wakeup = n_tty_write_wakeup, |
2519 | .fasync = n_tty_fasync, | |
24a89d1c | 2520 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2521 | }; |
572b9adb RG |
2522 | |
2523 | /** | |
2524 | * n_tty_inherit_ops - inherit N_TTY methods | |
2525 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2526 | * | |
593fb1ae | 2527 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2528 | * methods. |
2529 | */ | |
2530 | ||
2531 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2532 | { | |
2533 | *ops = tty_ldisc_N_TTY; | |
2534 | ops->owner = NULL; | |
2535 | ops->refcount = ops->flags = 0; | |
2536 | } | |
2537 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |