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