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 | * |
d2b6f447 PH |
1093 | * Performs input and output flush if !NOFLSH. In this context, the echo |
1094 | * buffer is 'output'. The signal is processed first to alert any current | |
1095 | * readers or writers to discontinue and exit their i/o loops. | |
1096 | * | |
8c985d18 | 1097 | * Locking: ctrl_lock |
1da177e4 | 1098 | */ |
4edf1827 | 1099 | |
4b293492 | 1100 | static void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1101 | { |
d2b6f447 | 1102 | struct n_tty_data *ldata = tty->disc_data; |
8c985d18 PH |
1103 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1104 | if (tty_pgrp) { | |
1105 | kill_pgrp(tty_pgrp, sig, 1); | |
1106 | put_pid(tty_pgrp); | |
1da177e4 | 1107 | } |
d2b6f447 PH |
1108 | |
1109 | if (!L_NOFLSH(tty)) { | |
1110 | up_read(&tty->termios_rwsem); | |
1111 | down_write(&tty->termios_rwsem); | |
1112 | ||
1113 | /* clear echo buffer */ | |
1114 | mutex_lock(&ldata->output_lock); | |
1115 | ldata->echo_head = ldata->echo_tail = 0; | |
1116 | ldata->echo_mark = ldata->echo_commit = 0; | |
1117 | mutex_unlock(&ldata->output_lock); | |
1118 | ||
1119 | /* clear output buffer */ | |
1120 | tty_driver_flush_buffer(tty); | |
1121 | ||
1122 | /* clear input buffer */ | |
1123 | reset_buffer_flags(tty->disc_data); | |
1124 | ||
1125 | /* notify pty master of flush */ | |
1126 | if (tty->link) | |
1127 | n_tty_packet_mode_flush(tty); | |
1128 | ||
1129 | up_write(&tty->termios_rwsem); | |
1130 | down_read(&tty->termios_rwsem); | |
1131 | } | |
1da177e4 LT |
1132 | } |
1133 | ||
1134 | /** | |
1135 | * n_tty_receive_break - handle break | |
1136 | * @tty: terminal | |
1137 | * | |
1138 | * An RS232 break event has been hit in the incoming bitstream. This | |
1139 | * can cause a variety of events depending upon the termios settings. | |
1140 | * | |
6d76bd26 PH |
1141 | * n_tty_receive_buf()/producer path: |
1142 | * caller holds non-exclusive termios_rwsem | |
6d76bd26 PH |
1143 | * |
1144 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1145 | */ |
4edf1827 | 1146 | |
4b293492 | 1147 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1148 | { |
57c94121 JS |
1149 | struct n_tty_data *ldata = tty->disc_data; |
1150 | ||
1da177e4 LT |
1151 | if (I_IGNBRK(tty)) |
1152 | return; | |
1153 | if (I_BRKINT(tty)) { | |
8c985d18 | 1154 | isig(SIGINT, tty); |
1da177e4 LT |
1155 | return; |
1156 | } | |
1157 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1158 | put_tty_queue('\377', ldata); |
1159 | put_tty_queue('\0', ldata); | |
1da177e4 | 1160 | } |
57c94121 | 1161 | put_tty_queue('\0', ldata); |
6c67716d | 1162 | if (waitqueue_active(&tty->read_wait)) |
57087d51 | 1163 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 LT |
1164 | } |
1165 | ||
1166 | /** | |
1167 | * n_tty_receive_overrun - handle overrun reporting | |
1168 | * @tty: terminal | |
1169 | * | |
1170 | * Data arrived faster than we could process it. While the tty | |
1171 | * driver has flagged this the bits that were missed are gone | |
1172 | * forever. | |
1173 | * | |
1174 | * Called from the receive_buf path so single threaded. Does not | |
1175 | * need locking as num_overrun and overrun_time are function | |
1176 | * private. | |
1177 | */ | |
4edf1827 | 1178 | |
4b293492 | 1179 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1180 | { |
53c5ee2c | 1181 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1182 | char buf[64]; |
1183 | ||
53c5ee2c JS |
1184 | ldata->num_overrun++; |
1185 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1186 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1187 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1188 | tty_name(tty, buf), | |
53c5ee2c JS |
1189 | ldata->num_overrun); |
1190 | ldata->overrun_time = jiffies; | |
1191 | ldata->num_overrun = 0; | |
1da177e4 LT |
1192 | } |
1193 | } | |
1194 | ||
1195 | /** | |
1196 | * n_tty_receive_parity_error - error notifier | |
1197 | * @tty: terminal device | |
1198 | * @c: character | |
1199 | * | |
1200 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1201 | * the error case if necessary. |
1202 | * | |
1203 | * n_tty_receive_buf()/producer path: | |
1204 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 1205 | */ |
4b293492 | 1206 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1207 | { |
57c94121 JS |
1208 | struct n_tty_data *ldata = tty->disc_data; |
1209 | ||
66528f90 PH |
1210 | if (I_INPCK(tty)) { |
1211 | if (I_IGNPAR(tty)) | |
1212 | return; | |
1213 | if (I_PARMRK(tty)) { | |
1214 | put_tty_queue('\377', ldata); | |
1215 | put_tty_queue('\0', ldata); | |
1216 | put_tty_queue(c, ldata); | |
1217 | } else | |
1218 | put_tty_queue('\0', ldata); | |
1219 | } else | |
57c94121 | 1220 | put_tty_queue(c, ldata); |
6c67716d | 1221 | if (waitqueue_active(&tty->read_wait)) |
57087d51 | 1222 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 LT |
1223 | } |
1224 | ||
b0ac50be PH |
1225 | static void |
1226 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1227 | { | |
d2b6f447 | 1228 | isig(signal, tty); |
b0ac50be PH |
1229 | if (I_IXON(tty)) |
1230 | start_tty(tty); | |
1231 | if (L_ECHO(tty)) { | |
1232 | echo_char(c, tty); | |
1233 | commit_echoes(tty); | |
e2613be5 PH |
1234 | } else |
1235 | process_echoes(tty); | |
b0ac50be PH |
1236 | return; |
1237 | } | |
1238 | ||
1da177e4 LT |
1239 | /** |
1240 | * n_tty_receive_char - perform processing | |
1241 | * @tty: terminal device | |
1242 | * @c: character | |
1243 | * | |
1244 | * Process an individual character of input received from the driver. | |
4edf1827 | 1245 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1246 | * driver above. |
6d76bd26 PH |
1247 | * |
1248 | * n_tty_receive_buf()/producer path: | |
1249 | * caller holds non-exclusive termios_rwsem | |
1250 | * publishes canon_head if canonical mode is active | |
e60d27c4 PH |
1251 | * |
1252 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1253 | */ |
1254 | ||
e60d27c4 | 1255 | static int |
4b1f79c2 | 1256 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1257 | { |
53c5ee2c | 1258 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1259 | |
1da177e4 LT |
1260 | if (I_IXON(tty)) { |
1261 | if (c == START_CHAR(tty)) { | |
1262 | start_tty(tty); | |
e2613be5 | 1263 | process_echoes(tty); |
e60d27c4 | 1264 | return 0; |
1da177e4 LT |
1265 | } |
1266 | if (c == STOP_CHAR(tty)) { | |
1267 | stop_tty(tty); | |
e60d27c4 | 1268 | return 0; |
1da177e4 LT |
1269 | } |
1270 | } | |
575537b3 | 1271 | |
1da177e4 | 1272 | if (L_ISIG(tty)) { |
b0ac50be PH |
1273 | if (c == INTR_CHAR(tty)) { |
1274 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1275 | return 0; |
b0ac50be PH |
1276 | } else if (c == QUIT_CHAR(tty)) { |
1277 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1278 | return 0; |
b0ac50be PH |
1279 | } else if (c == SUSP_CHAR(tty)) { |
1280 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1281 | return 0; |
1da177e4 LT |
1282 | } |
1283 | } | |
575537b3 | 1284 | |
855df3c0 PH |
1285 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1286 | start_tty(tty); | |
1287 | process_echoes(tty); | |
1288 | } | |
1289 | ||
575537b3 JP |
1290 | if (c == '\r') { |
1291 | if (I_IGNCR(tty)) | |
e60d27c4 | 1292 | return 0; |
575537b3 JP |
1293 | if (I_ICRNL(tty)) |
1294 | c = '\n'; | |
1295 | } else if (c == '\n' && I_INLCR(tty)) | |
1296 | c = '\r'; | |
1297 | ||
53c5ee2c | 1298 | if (ldata->icanon) { |
1da177e4 LT |
1299 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1300 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1301 | eraser(c, tty); | |
17bd7907 | 1302 | commit_echoes(tty); |
e60d27c4 | 1303 | return 0; |
1da177e4 LT |
1304 | } |
1305 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1306 | ldata->lnext = 1; |
1da177e4 | 1307 | if (L_ECHO(tty)) { |
57c94121 | 1308 | finish_erasing(ldata); |
1da177e4 | 1309 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1310 | echo_char_raw('^', ldata); |
1311 | echo_char_raw('\b', ldata); | |
17bd7907 | 1312 | commit_echoes(tty); |
1da177e4 LT |
1313 | } |
1314 | } | |
e60d27c4 | 1315 | return 1; |
1da177e4 | 1316 | } |
e60d27c4 | 1317 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1318 | size_t tail = ldata->canon_head; |
1da177e4 | 1319 | |
57c94121 | 1320 | finish_erasing(ldata); |
1da177e4 | 1321 | echo_char(c, tty); |
57c94121 | 1322 | echo_char_raw('\n', ldata); |
ba2e68ac | 1323 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1324 | echo_char(read_buf(ldata, tail), tty); |
1325 | tail++; | |
1da177e4 | 1326 | } |
17bd7907 | 1327 | commit_echoes(tty); |
e60d27c4 | 1328 | return 0; |
1da177e4 LT |
1329 | } |
1330 | if (c == '\n') { | |
acc71bba | 1331 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1332 | echo_char_raw('\n', ldata); |
17bd7907 | 1333 | commit_echoes(tty); |
1da177e4 LT |
1334 | } |
1335 | goto handle_newline; | |
1336 | } | |
1337 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1338 | c = __DISABLED_CHAR; |
1339 | goto handle_newline; | |
1340 | } | |
1341 | if ((c == EOL_CHAR(tty)) || | |
1342 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1343 | /* | |
1344 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1345 | */ | |
1346 | if (L_ECHO(tty)) { | |
1da177e4 | 1347 | /* Record the column of first canon char. */ |
ba2e68ac | 1348 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1349 | echo_set_canon_col(ldata); |
1da177e4 | 1350 | echo_char(c, tty); |
17bd7907 | 1351 | commit_echoes(tty); |
1da177e4 LT |
1352 | } |
1353 | /* | |
1354 | * XXX does PARMRK doubling happen for | |
1355 | * EOL_CHAR and EOL2_CHAR? | |
1356 | */ | |
001ba923 | 1357 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
57c94121 | 1358 | put_tty_queue(c, ldata); |
1da177e4 | 1359 | |
4edf1827 | 1360 | handle_newline: |
bc5a5e3f | 1361 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1362 | put_tty_queue(c, ldata); |
70aca71f | 1363 | smp_store_release(&ldata->canon_head, ldata->read_head); |
1da177e4 LT |
1364 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1365 | if (waitqueue_active(&tty->read_wait)) | |
57087d51 | 1366 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
e60d27c4 | 1367 | return 0; |
1da177e4 LT |
1368 | } |
1369 | } | |
4edf1827 | 1370 | |
acc71bba | 1371 | if (L_ECHO(tty)) { |
57c94121 | 1372 | finish_erasing(ldata); |
1da177e4 | 1373 | if (c == '\n') |
57c94121 | 1374 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1375 | else { |
1376 | /* Record the column of first canon char. */ | |
ba2e68ac | 1377 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1378 | echo_set_canon_col(ldata); |
1da177e4 LT |
1379 | echo_char(c, tty); |
1380 | } | |
17bd7907 | 1381 | commit_echoes(tty); |
1da177e4 LT |
1382 | } |
1383 | ||
001ba923 PH |
1384 | /* PARMRK doubling check */ |
1385 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
57c94121 | 1386 | put_tty_queue(c, ldata); |
1da177e4 | 1387 | |
57c94121 | 1388 | put_tty_queue(c, ldata); |
e60d27c4 | 1389 | return 0; |
4edf1827 | 1390 | } |
1da177e4 | 1391 | |
e60d27c4 PH |
1392 | static inline void |
1393 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1394 | { |
1395 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1396 | |
e60d27c4 PH |
1397 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1398 | start_tty(tty); | |
1399 | process_echoes(tty); | |
1400 | } | |
1401 | if (L_ECHO(tty)) { | |
1402 | finish_erasing(ldata); | |
1403 | /* Record the column of first canon char. */ | |
1404 | if (ldata->canon_head == ldata->read_head) | |
1405 | echo_set_canon_col(ldata); | |
1406 | echo_char(c, tty); | |
1407 | commit_echoes(tty); | |
4b1f79c2 | 1408 | } |
001ba923 PH |
1409 | /* PARMRK doubling check */ |
1410 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
e60d27c4 PH |
1411 | put_tty_queue(c, ldata); |
1412 | put_tty_queue(c, ldata); | |
1413 | } | |
4b1f79c2 | 1414 | |
eb3e4668 | 1415 | static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
e60d27c4 PH |
1416 | { |
1417 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1418 | } |
1419 | ||
7de971b0 PH |
1420 | static inline void |
1421 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1422 | { | |
1423 | struct n_tty_data *ldata = tty->disc_data; | |
1424 | ||
e60d27c4 PH |
1425 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1426 | start_tty(tty); | |
1427 | process_echoes(tty); | |
7de971b0 | 1428 | } |
e60d27c4 PH |
1429 | if (L_ECHO(tty)) { |
1430 | finish_erasing(ldata); | |
1431 | /* Record the column of first canon char. */ | |
1432 | if (ldata->canon_head == ldata->read_head) | |
1433 | echo_set_canon_col(ldata); | |
1434 | echo_char(c, tty); | |
1435 | commit_echoes(tty); | |
1436 | } | |
1437 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1438 | } |
1439 | ||
8dc4b25d | 1440 | static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) |
ad0cc7ba PH |
1441 | { |
1442 | if (I_ISTRIP(tty)) | |
1443 | c &= 0x7f; | |
1444 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1445 | c = tolower(c); | |
1446 | ||
1447 | if (I_IXON(tty)) { | |
1448 | if (c == STOP_CHAR(tty)) | |
1449 | stop_tty(tty); | |
1450 | else if (c == START_CHAR(tty) || | |
1451 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1452 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1453 | c != SUSP_CHAR(tty))) { | |
1454 | start_tty(tty); | |
1455 | process_echoes(tty); | |
1456 | } | |
1457 | } | |
1458 | } | |
1459 | ||
d2f8d7ab PH |
1460 | static void |
1461 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1462 | { | |
1463 | char buf[64]; | |
1464 | ||
1465 | switch (flag) { | |
1466 | case TTY_BREAK: | |
1467 | n_tty_receive_break(tty); | |
1468 | break; | |
1469 | case TTY_PARITY: | |
1470 | case TTY_FRAME: | |
1471 | n_tty_receive_parity_error(tty, c); | |
1472 | break; | |
1473 | case TTY_OVERRUN: | |
1474 | n_tty_receive_overrun(tty); | |
1475 | break; | |
1476 | default: | |
1477 | printk(KERN_ERR "%s: unknown flag %d\n", | |
1478 | tty_name(tty, buf), flag); | |
1479 | break; | |
1480 | } | |
1481 | } | |
1482 | ||
e60d27c4 PH |
1483 | static void |
1484 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1485 | { | |
1486 | struct n_tty_data *ldata = tty->disc_data; | |
1487 | ||
1488 | ldata->lnext = 0; | |
1489 | if (likely(flag == TTY_NORMAL)) { | |
1490 | if (I_ISTRIP(tty)) | |
1491 | c &= 0x7f; | |
1492 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1493 | c = tolower(c); | |
1494 | n_tty_receive_char(tty, c); | |
1495 | } else | |
1496 | n_tty_receive_char_flagged(tty, c, flag); | |
1497 | } | |
1498 | ||
4a23a4df PH |
1499 | static void |
1500 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1501 | char *fp, int count) | |
1502 | { | |
1503 | struct n_tty_data *ldata = tty->disc_data; | |
1504 | size_t n, head; | |
1505 | ||
1506 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1507 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1508 | memcpy(read_buf_addr(ldata, head), cp, n); |
1509 | ldata->read_head += n; | |
1510 | cp += n; | |
1511 | count -= n; | |
1512 | ||
1513 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1514 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1515 | memcpy(read_buf_addr(ldata, head), cp, n); |
1516 | ldata->read_head += n; | |
1517 | } | |
1518 | ||
554117bd PH |
1519 | static void |
1520 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1521 | char *fp, int count) | |
1522 | { | |
1523 | struct n_tty_data *ldata = tty->disc_data; | |
1524 | char flag = TTY_NORMAL; | |
1525 | ||
1526 | while (count--) { | |
1527 | if (fp) | |
1528 | flag = *fp++; | |
1529 | if (likely(flag == TTY_NORMAL)) | |
1530 | put_tty_queue(*cp++, ldata); | |
1531 | else | |
1532 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1533 | } | |
1534 | } | |
1535 | ||
ad0cc7ba PH |
1536 | static void |
1537 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1538 | char *fp, int count) | |
1539 | { | |
1540 | char flag = TTY_NORMAL; | |
1541 | ||
1542 | while (count--) { | |
1543 | if (fp) | |
1544 | flag = *fp++; | |
1545 | if (likely(flag == TTY_NORMAL)) | |
1546 | n_tty_receive_char_closing(tty, *cp++); | |
1547 | else | |
1548 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1549 | } | |
1550 | } | |
1551 | ||
7d88d637 PH |
1552 | static void |
1553 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1554 | char *fp, int count) |
1555 | { | |
1556 | struct n_tty_data *ldata = tty->disc_data; | |
1557 | char flag = TTY_NORMAL; | |
1558 | ||
1559 | while (count--) { | |
1560 | if (fp) | |
1561 | flag = *fp++; | |
1562 | if (likely(flag == TTY_NORMAL)) { | |
1563 | unsigned char c = *cp++; | |
1564 | ||
1565 | if (I_ISTRIP(tty)) | |
1566 | c &= 0x7f; | |
1567 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1568 | c = tolower(c); | |
1569 | if (L_EXTPROC(tty)) { | |
1570 | put_tty_queue(c, ldata); | |
1571 | continue; | |
1572 | } | |
e60d27c4 PH |
1573 | if (!test_bit(c, ldata->char_map)) |
1574 | n_tty_receive_char_inline(tty, c); | |
1575 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1576 | if (fp) | |
1577 | flag = *fp++; | |
1578 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1579 | count--; | |
1580 | } | |
6baad008 PH |
1581 | } else |
1582 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1583 | } | |
1584 | } | |
1585 | ||
1586 | static void | |
1587 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1588 | char *fp, int count) | |
7d88d637 | 1589 | { |
e60d27c4 | 1590 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1591 | char flag = TTY_NORMAL; |
1592 | ||
1593 | while (count--) { | |
1594 | if (fp) | |
1595 | flag = *fp++; | |
e60d27c4 PH |
1596 | if (likely(flag == TTY_NORMAL)) { |
1597 | unsigned char c = *cp++; | |
1598 | ||
1599 | if (!test_bit(c, ldata->char_map)) | |
1600 | n_tty_receive_char_fast(tty, c); | |
1601 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1602 | if (fp) | |
1603 | flag = *fp++; | |
1604 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1605 | count--; | |
1606 | } | |
1607 | } else | |
7d88d637 PH |
1608 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1609 | } | |
1610 | } | |
1611 | ||
24a89d1c PH |
1612 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1613 | char *fp, int count) | |
1da177e4 | 1614 | { |
53c5ee2c | 1615 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1616 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1617 | |
4a23a4df PH |
1618 | if (ldata->real_raw) |
1619 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1620 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1621 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1622 | else if (tty->closing && !L_EXTPROC(tty)) |
1623 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1624 | else { |
e60d27c4 PH |
1625 | if (ldata->lnext) { |
1626 | char flag = TTY_NORMAL; | |
1627 | ||
1628 | if (fp) | |
1629 | flag = *fp++; | |
1630 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1631 | count--; | |
1632 | } | |
1633 | ||
7de971b0 | 1634 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1635 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1636 | else | |
1637 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1638 | |
1639 | flush_echoes(tty); | |
f34d7a5b AC |
1640 | if (tty->ops->flush_chars) |
1641 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1642 | } |
1643 | ||
70aca71f PH |
1644 | if (ldata->icanon && !L_EXTPROC(tty)) |
1645 | return; | |
1646 | ||
1647 | /* publish read_head to consumer */ | |
1648 | smp_store_release(&ldata->commit_head, ldata->read_head); | |
1649 | ||
1650 | if ((read_cnt(ldata) >= ldata->minimum_to_wake) || L_EXTPROC(tty)) { | |
1da177e4 LT |
1651 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1652 | if (waitqueue_active(&tty->read_wait)) | |
57087d51 | 1653 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 | 1654 | } |
1da177e4 LT |
1655 | } |
1656 | ||
fb5ef9e7 PH |
1657 | /** |
1658 | * n_tty_receive_buf_common - process input | |
1659 | * @tty: device to receive input | |
1660 | * @cp: input chars | |
1661 | * @fp: flags for each char (if NULL, all chars are TTY_NORMAL) | |
1662 | * @count: number of input chars in @cp | |
1663 | * | |
1664 | * Called by the terminal driver when a block of characters has | |
1665 | * been received. This function must be called from soft contexts | |
1666 | * not from interrupt context. The driver is responsible for making | |
1667 | * calls one at a time and in order (or using flush_to_ldisc) | |
1668 | * | |
1669 | * Returns the # of input chars from @cp which were processed. | |
1670 | * | |
1671 | * In canonical mode, the maximum line length is 4096 chars (including | |
1672 | * the line termination char); lines longer than 4096 chars are | |
1673 | * truncated. After 4095 chars, input data is still processed but | |
1674 | * not stored. Overflow processing ensures the tty can always | |
1675 | * receive more input until at least one line can be read. | |
1676 | * | |
1677 | * In non-canonical mode, the read buffer will only accept 4095 chars; | |
1678 | * this provides the necessary space for a newline char if the input | |
1679 | * mode is switched to canonical. | |
1680 | * | |
1681 | * Note it is possible for the read buffer to _contain_ 4096 chars | |
1682 | * in non-canonical mode: the read buffer could already contain the | |
1683 | * maximum canon line of 4096 chars when the mode is switched to | |
1684 | * non-canonical. | |
1685 | * | |
1686 | * n_tty_receive_buf()/producer path: | |
1687 | * claims non-exclusive termios_rwsem | |
1688 | * publishes commit_head or canon_head | |
1689 | */ | |
5c32d123 PH |
1690 | static int |
1691 | n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, | |
1692 | char *fp, int count, int flow) | |
24a89d1c PH |
1693 | { |
1694 | struct n_tty_data *ldata = tty->disc_data; | |
fb5ef9e7 | 1695 | int room, n, rcvd = 0, overflow; |
24a89d1c | 1696 | |
9356b535 PH |
1697 | down_read(&tty->termios_rwsem); |
1698 | ||
19e2ad6a | 1699 | while (1) { |
70aca71f | 1700 | /* |
06c49f9f PH |
1701 | * When PARMRK is set, each input char may take up to 3 chars |
1702 | * in the read buf; reduce the buffer space avail by 3x | |
70aca71f PH |
1703 | * |
1704 | * If we are doing input canonicalization, and there are no | |
1705 | * pending newlines, let characters through without limit, so | |
1706 | * that erase characters will be handled. Other excess | |
1707 | * characters will be beeped. | |
1708 | * | |
1709 | * paired with store in *_copy_from_read_buf() -- guarantees | |
1710 | * the consumer has loaded the data in read_buf up to the new | |
1711 | * read_tail (so this producer will not overwrite unread data) | |
1712 | */ | |
1713 | size_t tail = smp_load_acquire(&ldata->read_tail); | |
70aca71f | 1714 | |
fb5ef9e7 | 1715 | room = N_TTY_BUF_SIZE - (ldata->read_head - tail); |
70aca71f | 1716 | if (I_PARMRK(tty)) |
fb5ef9e7 PH |
1717 | room = (room + 2) / 3; |
1718 | room--; | |
1719 | if (room <= 0) { | |
1720 | overflow = ldata->icanon && ldata->canon_head == tail; | |
1721 | if (overflow && room < 0) | |
1722 | ldata->read_head--; | |
1723 | room = overflow; | |
1724 | ldata->no_room = flow && !room; | |
1725 | } else | |
1726 | overflow = 0; | |
70aca71f | 1727 | |
19e2ad6a | 1728 | n = min(count, room); |
fb5ef9e7 | 1729 | if (!n) |
19e2ad6a | 1730 | break; |
fb5ef9e7 PH |
1731 | |
1732 | /* ignore parity errors if handling overflow */ | |
1733 | if (!overflow || !fp || *fp != TTY_PARITY) | |
1734 | __receive_buf(tty, cp, fp, n); | |
1735 | ||
19e2ad6a PH |
1736 | cp += n; |
1737 | if (fp) | |
1738 | fp += n; | |
1739 | count -= n; | |
1740 | rcvd += n; | |
4a23a4df | 1741 | } |
24a89d1c | 1742 | |
19e2ad6a | 1743 | tty->receive_room = room; |
fb5ef9e7 PH |
1744 | |
1745 | /* Unthrottle if handling overflow on pty */ | |
1746 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { | |
1747 | if (overflow) { | |
1748 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1749 | tty_unthrottle_safe(tty); | |
1750 | __tty_set_flow_change(tty, 0); | |
1751 | } | |
1752 | } else | |
1753 | n_tty_check_throttle(tty); | |
1754 | ||
9356b535 PH |
1755 | up_read(&tty->termios_rwsem); |
1756 | ||
19e2ad6a | 1757 | return rcvd; |
24a89d1c PH |
1758 | } |
1759 | ||
5c32d123 PH |
1760 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1761 | char *fp, int count) | |
1762 | { | |
1763 | n_tty_receive_buf_common(tty, cp, fp, count, 0); | |
1764 | } | |
1765 | ||
1766 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1767 | char *fp, int count) | |
1768 | { | |
1769 | return n_tty_receive_buf_common(tty, cp, fp, count, 1); | |
1770 | } | |
1771 | ||
1da177e4 LT |
1772 | int is_ignored(int sig) |
1773 | { | |
1774 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1775 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1776 | } |
1777 | ||
1778 | /** | |
1779 | * n_tty_set_termios - termios data changed | |
1780 | * @tty: terminal | |
1781 | * @old: previous data | |
1782 | * | |
1783 | * Called by the tty layer when the user changes termios flags so | |
1784 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1785 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1786 | * guaranteed that this function will not be re-entered or in progress |
1787 | * when the ldisc is closed. | |
17b82060 | 1788 | * |
6a1c0680 | 1789 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1790 | */ |
4edf1827 AC |
1791 | |
1792 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1793 | { |
53c5ee2c | 1794 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1795 | |
c786f74e | 1796 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { |
3fe780b3 | 1797 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1798 | ldata->line_start = ldata->read_tail; |
1799 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1800 | ldata->canon_head = ldata->read_tail; | |
1801 | ldata->push = 0; | |
1802 | } else { | |
1803 | set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), | |
1804 | ldata->read_flags); | |
1805 | ldata->canon_head = ldata->read_head; | |
1806 | ldata->push = 1; | |
1807 | } | |
70aca71f | 1808 | ldata->commit_head = ldata->read_head; |
53c5ee2c | 1809 | ldata->erasing = 0; |
6f9b028a | 1810 | ldata->lnext = 0; |
47afa7a5 AC |
1811 | } |
1812 | ||
53c5ee2c | 1813 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1814 | |
1da177e4 LT |
1815 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1816 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1817 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1818 | I_PARMRK(tty)) { | |
1bb9d562 | 1819 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1820 | |
1821 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1822 | set_bit('\r', ldata->char_map); |
1da177e4 | 1823 | if (I_INLCR(tty)) |
1bb9d562 | 1824 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1825 | |
1826 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1827 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1828 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1829 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1830 | set_bit('\n', ldata->char_map); | |
1831 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1832 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1833 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1834 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1835 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1836 | if (L_ECHO(tty)) |
1837 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1838 | ldata->char_map); |
1da177e4 LT |
1839 | } |
1840 | } | |
1841 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1842 | set_bit(START_CHAR(tty), ldata->char_map); |
1843 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1844 | } |
1845 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1846 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1847 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1848 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1849 | } |
1bb9d562 | 1850 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1851 | ldata->raw = 0; |
1852 | ldata->real_raw = 0; | |
1da177e4 | 1853 | } else { |
53c5ee2c | 1854 | ldata->raw = 1; |
1da177e4 LT |
1855 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1856 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1857 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1858 | ldata->real_raw = 1; |
1da177e4 | 1859 | else |
53c5ee2c | 1860 | ldata->real_raw = 0; |
1da177e4 | 1861 | } |
dab73b4e WY |
1862 | /* |
1863 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1864 | * been stopped by STOP_CHAR(tty) before it. | |
1865 | */ | |
e2613be5 | 1866 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { |
dab73b4e | 1867 | start_tty(tty); |
e2613be5 PH |
1868 | process_echoes(tty); |
1869 | } | |
dab73b4e | 1870 | |
f34d7a5b | 1871 | /* The termios change make the tty ready for I/O */ |
6c67716d PH |
1872 | if (waitqueue_active(&tty->write_wait)) |
1873 | wake_up_interruptible(&tty->write_wait); | |
1874 | if (waitqueue_active(&tty->read_wait)) | |
1875 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1876 | } |
1877 | ||
1878 | /** | |
1879 | * n_tty_close - close the ldisc for this tty | |
1880 | * @tty: device | |
1881 | * | |
4edf1827 AC |
1882 | * Called from the terminal layer when this line discipline is |
1883 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1884 | * discipline change. The function will not be called while other |
1885 | * ldisc methods are in progress. | |
1886 | */ | |
4edf1827 | 1887 | |
1da177e4 LT |
1888 | static void n_tty_close(struct tty_struct *tty) |
1889 | { | |
70ece7a7 JS |
1890 | struct n_tty_data *ldata = tty->disc_data; |
1891 | ||
79901317 PH |
1892 | if (tty->link) |
1893 | n_tty_packet_mode_flush(tty); | |
1894 | ||
20bafb3d | 1895 | vfree(ldata); |
70ece7a7 | 1896 | tty->disc_data = NULL; |
1da177e4 LT |
1897 | } |
1898 | ||
1899 | /** | |
1900 | * n_tty_open - open an ldisc | |
1901 | * @tty: terminal to open | |
1902 | * | |
4edf1827 | 1903 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1904 | * terminal device. Can sleep. Called serialized so that no |
1905 | * other events will occur in parallel. No further open will occur | |
1906 | * until a close. | |
1907 | */ | |
1908 | ||
1909 | static int n_tty_open(struct tty_struct *tty) | |
1910 | { | |
70ece7a7 JS |
1911 | struct n_tty_data *ldata; |
1912 | ||
20bafb3d PH |
1913 | /* Currently a malloc failure here can panic */ |
1914 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1915 | if (!ldata) |
1916 | goto err; | |
1917 | ||
53c5ee2c | 1918 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1919 | mutex_init(&ldata->atomic_read_lock); |
1920 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1921 | |
70ece7a7 | 1922 | tty->disc_data = ldata; |
b66f4fa5 | 1923 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1924 | ldata->column = 0; |
20bafb3d | 1925 | ldata->canon_column = 0; |
f6c8dbe6 | 1926 | ldata->minimum_to_wake = 1; |
20bafb3d PH |
1927 | ldata->num_overrun = 0; |
1928 | ldata->no_room = 0; | |
1929 | ldata->lnext = 0; | |
1da177e4 | 1930 | tty->closing = 0; |
b66f4fa5 PH |
1931 | /* indicate buffer work may resume */ |
1932 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1933 | n_tty_set_termios(tty, NULL); | |
1934 | tty_unthrottle(tty); | |
70ece7a7 | 1935 | |
1da177e4 | 1936 | return 0; |
70ece7a7 | 1937 | err: |
b91939f5 | 1938 | return -ENOMEM; |
1da177e4 LT |
1939 | } |
1940 | ||
eafbe67f | 1941 | static inline int input_available_p(struct tty_struct *tty, int poll) |
1da177e4 | 1942 | { |
53c5ee2c | 1943 | struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1944 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1945 | |
25e8d0ed PH |
1946 | if (ldata->icanon && !L_EXTPROC(tty)) |
1947 | return ldata->canon_head != ldata->read_tail; | |
1948 | else | |
70aca71f | 1949 | return ldata->commit_head - ldata->read_tail >= amt; |
1da177e4 LT |
1950 | } |
1951 | ||
1952 | /** | |
bbd20759 | 1953 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1954 | * @tty: terminal device |
1955 | * @b: user data | |
1956 | * @nr: size of data | |
1957 | * | |
11a96d18 | 1958 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1959 | * ICANON is off; it copies characters straight from the tty queue to |
1960 | * user space directly. It can be profitably called twice; once to | |
1961 | * drain the space from the tail pointer to the (physical) end of the | |
1962 | * buffer, and once to drain the space from the (physical) beginning of | |
1963 | * the buffer to head pointer. | |
1964 | * | |
bddc7152 | 1965 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1966 | * |
6d76bd26 PH |
1967 | * n_tty_read()/consumer path: |
1968 | * caller holds non-exclusive termios_rwsem | |
1969 | * read_tail published | |
1da177e4 | 1970 | */ |
4edf1827 | 1971 | |
33f0f88f | 1972 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1973 | unsigned char __user **b, |
1974 | size_t *nr) | |
1975 | ||
1976 | { | |
53c5ee2c | 1977 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1978 | int retval; |
1979 | size_t n; | |
3fa10cc8 | 1980 | bool is_eof; |
70aca71f | 1981 | size_t head = smp_load_acquire(&ldata->commit_head); |
bc5a5e3f | 1982 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1983 | |
1984 | retval = 0; | |
70aca71f | 1985 | n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail); |
1da177e4 | 1986 | n = min(*nr, n); |
1da177e4 | 1987 | if (n) { |
bc5a5e3f | 1988 | retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
1da177e4 | 1989 | n -= retval; |
bc5a5e3f PH |
1990 | is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); |
1991 | tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, | |
53c5ee2c | 1992 | ldata->icanon); |
70aca71f | 1993 | smp_store_release(&ldata->read_tail, ldata->read_tail + n); |
26df6d13 | 1994 | /* Turn single EOF into zero-length read */ |
70aca71f PH |
1995 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && |
1996 | (head == ldata->read_tail)) | |
3fa10cc8 | 1997 | n = 0; |
1da177e4 LT |
1998 | *b += n; |
1999 | *nr -= n; | |
2000 | } | |
2001 | return retval; | |
2002 | } | |
2003 | ||
88bb0de3 | 2004 | /** |
32f13521 | 2005 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
2006 | * @tty: terminal device |
2007 | * @b: user data | |
2008 | * @nr: size of data | |
2009 | * | |
2010 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
2011 | * it copies one line of input up to and including the line-delimiting |
2012 | * character into the user-space buffer. | |
88bb0de3 | 2013 | * |
4d0ed182 PH |
2014 | * NB: When termios is changed from non-canonical to canonical mode and |
2015 | * the read buffer contains data, n_tty_set_termios() simulates an EOF | |
2016 | * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. | |
2017 | * This causes data already processed as input to be immediately available | |
2018 | * as input although a newline has not been received. | |
2019 | * | |
88bb0de3 | 2020 | * Called under the atomic_read_lock mutex |
6d76bd26 PH |
2021 | * |
2022 | * n_tty_read()/consumer path: | |
2023 | * caller holds non-exclusive termios_rwsem | |
2024 | * read_tail published | |
88bb0de3 PH |
2025 | */ |
2026 | ||
32f13521 PH |
2027 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
2028 | unsigned char __user **b, | |
2029 | size_t *nr) | |
88bb0de3 PH |
2030 | { |
2031 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 2032 | size_t n, size, more, c; |
bc5a5e3f PH |
2033 | size_t eol; |
2034 | size_t tail; | |
2035 | int ret, found = 0; | |
40d5e090 | 2036 | bool eof_push = 0; |
88bb0de3 PH |
2037 | |
2038 | /* N.B. avoid overrun if nr == 0 */ | |
70aca71f | 2039 | n = min(*nr, smp_load_acquire(&ldata->canon_head) - ldata->read_tail); |
6d76bd26 | 2040 | if (!n) |
32f13521 | 2041 | return 0; |
88bb0de3 | 2042 | |
bc5a5e3f | 2043 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
2044 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
2045 | ||
bc5a5e3f | 2046 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2047 | __func__, *nr, tail, n, size); |
2048 | ||
2049 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2050 | more = n - (size - tail); | |
2051 | if (eol == N_TTY_BUF_SIZE && more) { | |
2052 | /* scan wrapped without finding set bit */ | |
2053 | eol = find_next_bit(ldata->read_flags, more, 0); | |
2054 | if (eol != more) | |
2055 | found = 1; | |
2056 | } else if (eol != size) | |
2057 | found = 1; | |
2058 | ||
2059 | size = N_TTY_BUF_SIZE - tail; | |
c77569d2 PH |
2060 | n = eol - tail; |
2061 | if (n > 4096) | |
2062 | n += 4096; | |
2063 | n += found; | |
32f13521 PH |
2064 | c = n; |
2065 | ||
4d0ed182 | 2066 | if (found && !ldata->push && read_buf(ldata, eol) == __DISABLED_CHAR) { |
32f13521 | 2067 | n--; |
40d5e090 PH |
2068 | eof_push = !n && ldata->read_tail != ldata->line_start; |
2069 | } | |
32f13521 | 2070 | |
bc5a5e3f | 2071 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", |
32f13521 PH |
2072 | __func__, eol, found, n, c, size, more); |
2073 | ||
32f13521 | 2074 | if (n > size) { |
bc5a5e3f | 2075 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), size); |
32f13521 PH |
2076 | if (ret) |
2077 | return -EFAULT; | |
2078 | ret = copy_to_user(*b + size, ldata->read_buf, n - size); | |
2079 | } else | |
bc5a5e3f | 2080 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
32f13521 PH |
2081 | |
2082 | if (ret) | |
2083 | return -EFAULT; | |
2084 | *b += n; | |
2085 | *nr -= n; | |
2086 | ||
a73d3d69 | 2087 | if (found) |
6d76bd26 | 2088 | clear_bit(eol, ldata->read_flags); |
70aca71f | 2089 | smp_store_release(&ldata->read_tail, ldata->read_tail + c); |
88bb0de3 | 2090 | |
40d5e090 | 2091 | if (found) { |
4d0ed182 PH |
2092 | if (!ldata->push) |
2093 | ldata->line_start = ldata->read_tail; | |
2094 | else | |
2095 | ldata->push = 0; | |
32f13521 | 2096 | tty_audit_push(tty); |
40d5e090 PH |
2097 | } |
2098 | return eof_push ? -EAGAIN : 0; | |
88bb0de3 PH |
2099 | } |
2100 | ||
cc4191dc | 2101 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2102 | size_t, loff_t *); |
1da177e4 LT |
2103 | |
2104 | /** | |
2105 | * job_control - check job control | |
2106 | * @tty: tty | |
2107 | * @file: file handle | |
2108 | * | |
2109 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2110 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2111 | * error code if action should be taken. |
04f378b1 | 2112 | * |
01a5e440 PH |
2113 | * Locking: redirected write test is safe |
2114 | * current->signal->tty check is safe | |
2115 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2116 | */ |
4edf1827 | 2117 | |
1da177e4 LT |
2118 | static int job_control(struct tty_struct *tty, struct file *file) |
2119 | { | |
2120 | /* Job control check -- must be done at start and after | |
2121 | every sleep (POSIX.1 7.1.1.4). */ | |
2122 | /* NOTE: not yet done after every sleep pending a thorough | |
2123 | check of the logic of this change. -- jlc */ | |
2124 | /* don't stop on /dev/console */ | |
01a5e440 PH |
2125 | if (file->f_op->write == redirected_tty_write || |
2126 | current->signal->tty != tty) | |
2127 | return 0; | |
2128 | ||
2129 | spin_lock_irq(&tty->ctrl_lock); | |
2130 | if (!tty->pgrp) | |
2131 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
2132 | else if (task_pgrp(current) != tty->pgrp) { | |
2133 | spin_unlock_irq(&tty->ctrl_lock); | |
2134 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
2135 | return -EIO; | |
2136 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
2137 | set_thread_flag(TIF_SIGPENDING); | |
2138 | return -ERESTARTSYS; | |
1da177e4 | 2139 | } |
01a5e440 | 2140 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
2141 | return 0; |
2142 | } | |
4edf1827 | 2143 | |
1da177e4 LT |
2144 | |
2145 | /** | |
11a96d18 | 2146 | * n_tty_read - read function for tty |
1da177e4 LT |
2147 | * @tty: tty device |
2148 | * @file: file object | |
2149 | * @buf: userspace buffer pointer | |
2150 | * @nr: size of I/O | |
2151 | * | |
2152 | * Perform reads for the line discipline. We are guaranteed that the | |
2153 | * line discipline will not be closed under us but we may get multiple | |
2154 | * parallel readers and must handle this ourselves. We may also get | |
2155 | * a hangup. Always called in user context, may sleep. | |
2156 | * | |
2157 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2158 | * |
2159 | * n_tty_read()/consumer path: | |
2160 | * claims non-exclusive termios_rwsem | |
2161 | * publishes read_tail | |
1da177e4 | 2162 | */ |
4edf1827 | 2163 | |
11a96d18 | 2164 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2165 | unsigned char __user *buf, size_t nr) |
2166 | { | |
53c5ee2c | 2167 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 2168 | unsigned char __user *b = buf; |
97d9e28d | 2169 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2170 | int c; |
2171 | int minimum, time; | |
2172 | ssize_t retval = 0; | |
1da177e4 | 2173 | long timeout; |
04f378b1 | 2174 | int packet; |
2c5dc464 | 2175 | size_t tail; |
1da177e4 | 2176 | |
1da177e4 | 2177 | c = job_control(tty, file); |
4edf1827 | 2178 | if (c < 0) |
1da177e4 | 2179 | return c; |
4edf1827 | 2180 | |
aefceaf4 PH |
2181 | /* |
2182 | * Internal serialization of reads. | |
2183 | */ | |
2184 | if (file->f_flags & O_NONBLOCK) { | |
2185 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2186 | return -EAGAIN; | |
2187 | } else { | |
2188 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2189 | return -ERESTARTSYS; | |
2190 | } | |
2191 | ||
9356b535 PH |
2192 | down_read(&tty->termios_rwsem); |
2193 | ||
1da177e4 LT |
2194 | minimum = time = 0; |
2195 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2196 | if (!ldata->icanon) { |
1da177e4 LT |
2197 | minimum = MIN_CHAR(tty); |
2198 | if (minimum) { | |
a6e54319 | 2199 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2200 | if (time) |
f6c8dbe6 | 2201 | ldata->minimum_to_wake = 1; |
1da177e4 | 2202 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
2203 | (ldata->minimum_to_wake > minimum)) |
2204 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 2205 | } else { |
a6e54319 | 2206 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2207 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2208 | } |
2209 | } | |
2210 | ||
04f378b1 | 2211 | packet = tty->packet; |
2c5dc464 | 2212 | tail = ldata->read_tail; |
1da177e4 LT |
2213 | |
2214 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2215 | while (nr) { |
2216 | /* First test for status change. */ | |
04f378b1 | 2217 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2218 | unsigned char cs; |
2219 | if (b != buf) | |
2220 | break; | |
6054c16e | 2221 | spin_lock_irq(&tty->link->ctrl_lock); |
1da177e4 LT |
2222 | cs = tty->link->ctrl_status; |
2223 | tty->link->ctrl_status = 0; | |
6054c16e | 2224 | spin_unlock_irq(&tty->link->ctrl_lock); |
522ed776 | 2225 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2226 | retval = -EFAULT; |
2227 | b--; | |
2228 | break; | |
2229 | } | |
2230 | nr--; | |
2231 | break; | |
2232 | } | |
4edf1827 | 2233 | |
f6c8dbe6 | 2234 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2235 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2236 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2237 | |
1da177e4 LT |
2238 | if (!input_available_p(tty, 0)) { |
2239 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
52bce7f8 PH |
2240 | retval = -EIO; |
2241 | break; | |
f8747d4a | 2242 | } |
52bce7f8 PH |
2243 | if (tty_hung_up_p(file)) |
2244 | break; | |
2245 | if (!timeout) | |
2246 | break; | |
2247 | if (file->f_flags & O_NONBLOCK) { | |
2248 | retval = -EAGAIN; | |
1da177e4 LT |
2249 | break; |
2250 | } | |
52bce7f8 PH |
2251 | if (signal_pending(current)) { |
2252 | retval = -ERESTARTSYS; | |
2253 | break; | |
2254 | } | |
52bce7f8 | 2255 | up_read(&tty->termios_rwsem); |
9356b535 | 2256 | |
37da7bbb LT |
2257 | timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, |
2258 | timeout); | |
9356b535 | 2259 | |
52bce7f8 PH |
2260 | down_read(&tty->termios_rwsem); |
2261 | continue; | |
1da177e4 LT |
2262 | } |
2263 | ||
53c5ee2c | 2264 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2265 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
40d5e090 PH |
2266 | if (retval == -EAGAIN) { |
2267 | retval = 0; | |
2268 | continue; | |
2269 | } else if (retval) | |
1da177e4 LT |
2270 | break; |
2271 | } else { | |
2272 | int uncopied; | |
95ea90db PH |
2273 | |
2274 | /* Deal with packet mode. */ | |
2275 | if (packet && b == buf) { | |
2276 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { | |
2277 | retval = -EFAULT; | |
2278 | b--; | |
2279 | break; | |
2280 | } | |
2281 | nr--; | |
2282 | } | |
2283 | ||
1da177e4 LT |
2284 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2285 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2286 | if (uncopied) { | |
2287 | retval = -EFAULT; | |
2288 | break; | |
2289 | } | |
2290 | } | |
2291 | ||
6367ca72 | 2292 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2293 | |
2294 | if (b - buf >= minimum) | |
2295 | break; | |
2296 | if (time) | |
2297 | timeout = time; | |
2298 | } | |
2c5dc464 PH |
2299 | if (tail != ldata->read_tail) |
2300 | n_tty_kick_worker(tty); | |
42458f41 PH |
2301 | up_read(&tty->termios_rwsem); |
2302 | ||
1da177e4 | 2303 | remove_wait_queue(&tty->read_wait, &wait); |
1da177e4 | 2304 | if (!waitqueue_active(&tty->read_wait)) |
f6c8dbe6 | 2305 | ldata->minimum_to_wake = minimum; |
1da177e4 | 2306 | |
aebf0453 PH |
2307 | mutex_unlock(&ldata->atomic_read_lock); |
2308 | ||
40d5e090 PH |
2309 | if (b - buf) |
2310 | retval = b - buf; | |
1da177e4 LT |
2311 | |
2312 | return retval; | |
2313 | } | |
2314 | ||
2315 | /** | |
11a96d18 | 2316 | * n_tty_write - write function for tty |
1da177e4 LT |
2317 | * @tty: tty device |
2318 | * @file: file object | |
2319 | * @buf: userspace buffer pointer | |
2320 | * @nr: size of I/O | |
2321 | * | |
a88a69c9 | 2322 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2323 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2324 | * and other such events. Since the receive code will echo characters, |
2325 | * thus calling driver write methods, the output_lock is used in | |
2326 | * the output processing functions called here as well as in the | |
2327 | * echo processing function to protect the column state and space | |
2328 | * left in the buffer. | |
1da177e4 LT |
2329 | * |
2330 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2331 | * |
2332 | * Locking: output_lock to protect column state and space left | |
2333 | * (note that the process_output*() functions take this | |
2334 | * lock themselves) | |
1da177e4 | 2335 | */ |
4edf1827 | 2336 | |
11a96d18 | 2337 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2338 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2339 | { |
2340 | const unsigned char *b = buf; | |
97d9e28d | 2341 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2342 | int c; |
2343 | ssize_t retval = 0; | |
2344 | ||
2345 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2346 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2347 | retval = tty_check_change(tty); | |
2348 | if (retval) | |
2349 | return retval; | |
2350 | } | |
2351 | ||
9356b535 PH |
2352 | down_read(&tty->termios_rwsem); |
2353 | ||
a88a69c9 JP |
2354 | /* Write out any echoed characters that are still pending */ |
2355 | process_echoes(tty); | |
300a6204 | 2356 | |
1da177e4 LT |
2357 | add_wait_queue(&tty->write_wait, &wait); |
2358 | while (1) { | |
1da177e4 LT |
2359 | if (signal_pending(current)) { |
2360 | retval = -ERESTARTSYS; | |
2361 | break; | |
2362 | } | |
2363 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2364 | retval = -EIO; | |
2365 | break; | |
2366 | } | |
582f5590 | 2367 | if (O_OPOST(tty)) { |
1da177e4 | 2368 | while (nr > 0) { |
a88a69c9 | 2369 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2370 | if (num < 0) { |
2371 | if (num == -EAGAIN) | |
2372 | break; | |
2373 | retval = num; | |
2374 | goto break_out; | |
2375 | } | |
2376 | b += num; | |
2377 | nr -= num; | |
2378 | if (nr == 0) | |
2379 | break; | |
2380 | c = *b; | |
a88a69c9 | 2381 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2382 | break; |
2383 | b++; nr--; | |
2384 | } | |
f34d7a5b AC |
2385 | if (tty->ops->flush_chars) |
2386 | tty->ops->flush_chars(tty); | |
1da177e4 | 2387 | } else { |
4291086b PH |
2388 | struct n_tty_data *ldata = tty->disc_data; |
2389 | ||
d6afe27b | 2390 | while (nr > 0) { |
4291086b | 2391 | mutex_lock(&ldata->output_lock); |
f34d7a5b | 2392 | c = tty->ops->write(tty, b, nr); |
4291086b | 2393 | mutex_unlock(&ldata->output_lock); |
d6afe27b RZ |
2394 | if (c < 0) { |
2395 | retval = c; | |
2396 | goto break_out; | |
2397 | } | |
2398 | if (!c) | |
2399 | break; | |
2400 | b += c; | |
2401 | nr -= c; | |
1da177e4 | 2402 | } |
1da177e4 LT |
2403 | } |
2404 | if (!nr) | |
2405 | break; | |
2406 | if (file->f_flags & O_NONBLOCK) { | |
2407 | retval = -EAGAIN; | |
2408 | break; | |
2409 | } | |
9356b535 PH |
2410 | up_read(&tty->termios_rwsem); |
2411 | ||
97d9e28d | 2412 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
9356b535 PH |
2413 | |
2414 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2415 | } |
2416 | break_out: | |
1da177e4 | 2417 | remove_wait_queue(&tty->write_wait, &wait); |
ff8cb0fd TP |
2418 | if (b - buf != nr && tty->fasync) |
2419 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2420 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2421 | return (b - buf) ? b - buf : retval; |
2422 | } | |
2423 | ||
2424 | /** | |
11a96d18 | 2425 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2426 | * @tty: terminal device |
2427 | * @file: file accessing it | |
2428 | * @wait: poll table | |
2429 | * | |
2430 | * Called when the line discipline is asked to poll() for data or | |
2431 | * for special events. This code is not serialized with respect to | |
2432 | * other events save open/close. | |
2433 | * | |
2434 | * This code must be sure never to sleep through a hangup. | |
2435 | * Called without the kernel lock held - fine | |
1da177e4 | 2436 | */ |
4edf1827 | 2437 | |
11a96d18 | 2438 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2439 | poll_table *wait) |
1da177e4 | 2440 | { |
f6c8dbe6 | 2441 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2442 | unsigned int mask = 0; |
2443 | ||
2444 | poll_wait(file, &tty->read_wait, wait); | |
2445 | poll_wait(file, &tty->write_wait, wait); | |
eafbe67f | 2446 | if (input_available_p(tty, 1)) |
1da177e4 LT |
2447 | mask |= POLLIN | POLLRDNORM; |
2448 | if (tty->packet && tty->link->ctrl_status) | |
2449 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2ce3c10c PH |
2450 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) |
2451 | mask |= POLLHUP; | |
1da177e4 LT |
2452 | if (tty_hung_up_p(file)) |
2453 | mask |= POLLHUP; | |
2454 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2455 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2456 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2457 | else |
f6c8dbe6 | 2458 | ldata->minimum_to_wake = 1; |
1da177e4 | 2459 | } |
f34d7a5b AC |
2460 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2461 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2462 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2463 | mask |= POLLOUT | POLLWRNORM; |
2464 | return mask; | |
2465 | } | |
2466 | ||
57c94121 | 2467 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2468 | { |
bc5a5e3f | 2469 | size_t nr, head, tail; |
47afa7a5 | 2470 | |
a73d3d69 | 2471 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2472 | return 0; |
ba2e68ac JS |
2473 | head = ldata->canon_head; |
2474 | tail = ldata->read_tail; | |
bc5a5e3f | 2475 | nr = head - tail; |
47afa7a5 AC |
2476 | /* Skip EOF-chars.. */ |
2477 | while (head != tail) { | |
bc5a5e3f PH |
2478 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2479 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2480 | nr--; |
bc5a5e3f | 2481 | tail++; |
47afa7a5 AC |
2482 | } |
2483 | return nr; | |
2484 | } | |
2485 | ||
2486 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2487 | unsigned int cmd, unsigned long arg) | |
2488 | { | |
ba2e68ac | 2489 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2490 | int retval; |
2491 | ||
2492 | switch (cmd) { | |
2493 | case TIOCOUTQ: | |
2494 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2495 | case TIOCINQ: | |
6d76bd26 | 2496 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2497 | if (L_ICANON(tty)) |
57c94121 | 2498 | retval = inq_canon(ldata); |
6d76bd26 PH |
2499 | else |
2500 | retval = read_cnt(ldata); | |
2501 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2502 | return put_user(retval, (unsigned int __user *) arg); |
2503 | default: | |
2504 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2505 | } | |
2506 | } | |
2507 | ||
f6c8dbe6 PH |
2508 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2509 | { | |
2510 | struct n_tty_data *ldata = tty->disc_data; | |
2511 | ||
2512 | if (!waitqueue_active(&tty->read_wait)) { | |
2513 | if (on) | |
2514 | ldata->minimum_to_wake = 1; | |
2515 | else if (!tty->fasync) | |
2516 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2517 | } | |
2518 | } | |
2519 | ||
a352def2 | 2520 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2521 | .magic = TTY_LDISC_MAGIC, |
2522 | .name = "n_tty", | |
2523 | .open = n_tty_open, | |
2524 | .close = n_tty_close, | |
2525 | .flush_buffer = n_tty_flush_buffer, | |
2526 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2527 | .read = n_tty_read, |
2528 | .write = n_tty_write, | |
e10cc1df PF |
2529 | .ioctl = n_tty_ioctl, |
2530 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2531 | .poll = n_tty_poll, |
e10cc1df | 2532 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2533 | .write_wakeup = n_tty_write_wakeup, |
2534 | .fasync = n_tty_fasync, | |
24a89d1c | 2535 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2536 | }; |
572b9adb RG |
2537 | |
2538 | /** | |
2539 | * n_tty_inherit_ops - inherit N_TTY methods | |
2540 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2541 | * | |
593fb1ae | 2542 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2543 | * methods. |
2544 | */ | |
2545 | ||
2546 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2547 | { | |
2548 | *ops = tty_ldisc_N_TTY; | |
2549 | ops->owner = NULL; | |
2550 | ops->refcount = ops->flags = 0; | |
2551 | } | |
2552 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |