Commit | Line | Data |
---|---|---|
e3b3d0f5 | 1 | // SPDX-License-Identifier: GPL-1.0+ |
1da177e4 LT |
2 | /* |
3 | * n_tty.c --- implements the N_TTY line discipline. | |
4edf1827 | 4 | * |
1da177e4 LT |
5 | * This code used to be in tty_io.c, but things are getting hairy |
6 | * enough that it made sense to split things off. (The N_TTY | |
7 | * processing has changed so much that it's hardly recognizable, | |
8 | * anyway...) | |
9 | * | |
10 | * Note that the open routine for N_TTY is guaranteed never to return | |
11 | * an error. This is because Linux will fall back to setting a line | |
4edf1827 | 12 | * to N_TTY if it can not switch to any other line discipline. |
1da177e4 LT |
13 | * |
14 | * Written by Theodore Ts'o, Copyright 1994. | |
4edf1827 | 15 | * |
1da177e4 LT |
16 | * This file also contains code originally written by Linus Torvalds, |
17 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. | |
4edf1827 | 18 | * |
1da177e4 LT |
19 | * Reduced memory usage for older ARM systems - Russell King. |
20 | * | |
4edf1827 | 21 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
1da177e4 LT |
22 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
23 | * who actually finally proved there really was a race. | |
24 | * | |
25 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to | |
26 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. | |
11a96d18 | 27 | * Also fixed a bug in BLOCKING mode where n_tty_write returns |
1da177e4 LT |
28 | * EAGAIN |
29 | */ | |
30 | ||
31 | #include <linux/types.h> | |
32 | #include <linux/major.h> | |
33 | #include <linux/errno.h> | |
34 | #include <linux/signal.h> | |
35 | #include <linux/fcntl.h> | |
36 | #include <linux/sched.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/tty.h> | |
39 | #include <linux/timer.h> | |
40 | #include <linux/ctype.h> | |
41 | #include <linux/mm.h> | |
42 | #include <linux/string.h> | |
43 | #include <linux/slab.h> | |
44 | #include <linux/poll.h> | |
45 | #include <linux/bitops.h> | |
522ed776 MT |
46 | #include <linux/audit.h> |
47 | #include <linux/file.h> | |
300a6204 | 48 | #include <linux/uaccess.h> |
572b9adb | 49 | #include <linux/module.h> |
593fb1ae | 50 | #include <linux/ratelimit.h> |
86e35aea | 51 | #include <linux/vmalloc.h> |
98602c01 | 52 | #include "tty.h" |
1da177e4 | 53 | |
a5db4826 VV |
54 | /* |
55 | * Until this number of characters is queued in the xmit buffer, select will | |
56 | * return "we have room for writes". | |
57 | */ | |
1da177e4 LT |
58 | #define WAKEUP_CHARS 256 |
59 | ||
60 | /* | |
61 | * This defines the low- and high-watermarks for throttling and | |
62 | * unthrottling the TTY driver. These watermarks are used for | |
63 | * controlling the space in the read buffer. | |
64 | */ | |
65 | #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ | |
bbd20759 | 66 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
1da177e4 | 67 | |
a88a69c9 JP |
68 | /* |
69 | * Special byte codes used in the echo buffer to represent operations | |
70 | * or special handling of characters. Bytes in the echo buffer that | |
71 | * are not part of such special blocks are treated as normal character | |
72 | * codes. | |
73 | */ | |
74 | #define ECHO_OP_START 0xff | |
75 | #define ECHO_OP_MOVE_BACK_COL 0x80 | |
76 | #define ECHO_OP_SET_CANON_COL 0x81 | |
77 | #define ECHO_OP_ERASE_TAB 0x82 | |
78 | ||
cbfd0340 PH |
79 | #define ECHO_COMMIT_WATERMARK 256 |
80 | #define ECHO_BLOCK 256 | |
81 | #define ECHO_DISCARD_WATERMARK N_TTY_BUF_SIZE - (ECHO_BLOCK + 32) | |
82 | ||
83 | ||
32f13521 PH |
84 | #undef N_TTY_TRACE |
85 | #ifdef N_TTY_TRACE | |
86 | # define n_tty_trace(f, args...) trace_printk(f, ##args) | |
87 | #else | |
a287885f | 88 | # define n_tty_trace(f, args...) no_printk(f, ##args) |
32f13521 PH |
89 | #endif |
90 | ||
70ece7a7 | 91 | struct n_tty_data { |
fb7aa03d PH |
92 | /* producer-published */ |
93 | size_t read_head; | |
70aca71f | 94 | size_t commit_head; |
fb7aa03d | 95 | size_t canon_head; |
9dfd16dd PH |
96 | size_t echo_head; |
97 | size_t echo_commit; | |
1075a6e2 | 98 | size_t echo_mark; |
1bb9d562 | 99 | DECLARE_BITMAP(char_map, 256); |
fb7aa03d PH |
100 | |
101 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c JS |
102 | unsigned long overrun_time; |
103 | int num_overrun; | |
104 | ||
24a89d1c PH |
105 | /* non-atomic */ |
106 | bool no_room; | |
107 | ||
fb7aa03d | 108 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c | 109 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
4d0ed182 | 110 | unsigned char push:1; |
3fe780b3 | 111 | |
fb7aa03d | 112 | /* shared by producer and consumer */ |
20bafb3d | 113 | char read_buf[N_TTY_BUF_SIZE]; |
3fe780b3 | 114 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
20bafb3d | 115 | unsigned char echo_buf[N_TTY_BUF_SIZE]; |
ba2e68ac | 116 | |
fb7aa03d PH |
117 | /* consumer-published */ |
118 | size_t read_tail; | |
40d5e090 | 119 | size_t line_start; |
fb7aa03d | 120 | |
6bb6fa69 IJ |
121 | /* # of chars looked ahead (to find software flow control chars) */ |
122 | size_t lookahead_count; | |
123 | ||
fb7aa03d PH |
124 | /* protected by output lock */ |
125 | unsigned int column; | |
ba2e68ac | 126 | unsigned int canon_column; |
9dfd16dd | 127 | size_t echo_tail; |
bddc7152 JS |
128 | |
129 | struct mutex atomic_read_lock; | |
130 | struct mutex output_lock; | |
70ece7a7 JS |
131 | }; |
132 | ||
3d63b7e4 TH |
133 | #define MASK(x) ((x) & (N_TTY_BUF_SIZE - 1)) |
134 | ||
ce74117a PH |
135 | static inline size_t read_cnt(struct n_tty_data *ldata) |
136 | { | |
a2f73be8 | 137 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
138 | } |
139 | ||
bc5a5e3f PH |
140 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
141 | { | |
142 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
143 | } | |
144 | ||
145 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
146 | { | |
147 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
148 | } | |
149 | ||
addaebcc PH |
150 | static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) |
151 | { | |
ebec3f8f | 152 | smp_rmb(); /* Matches smp_wmb() in add_echo_byte(). */ |
addaebcc PH |
153 | return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; |
154 | } | |
155 | ||
156 | static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) | |
157 | { | |
158 | return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
159 | } | |
160 | ||
b97b3d9f GK |
161 | /* If we are not echoing the data, perhaps this is a secret so erase it */ |
162 | static void zero_buffer(struct tty_struct *tty, u8 *buffer, int size) | |
163 | { | |
164 | bool icanon = !!L_ICANON(tty); | |
165 | bool no_echo = !L_ECHO(tty); | |
166 | ||
167 | if (icanon && no_echo) | |
168 | memset(buffer, 0x00, size); | |
169 | } | |
170 | ||
3b830a9c | 171 | static void tty_copy(struct tty_struct *tty, void *to, size_t tail, size_t n) |
72586c60 LA |
172 | { |
173 | struct n_tty_data *ldata = tty->disc_data; | |
679e7c29 | 174 | size_t size = N_TTY_BUF_SIZE - tail; |
b97b3d9f | 175 | void *from = read_buf_addr(ldata, tail); |
679e7c29 PH |
176 | |
177 | if (n > size) { | |
309426ae | 178 | tty_audit_add_data(tty, from, size); |
3b830a9c LT |
179 | memcpy(to, from, size); |
180 | zero_buffer(tty, from, size); | |
679e7c29 PH |
181 | to += size; |
182 | n -= size; | |
183 | from = ldata->read_buf; | |
184 | } | |
72586c60 | 185 | |
309426ae | 186 | tty_audit_add_data(tty, from, n); |
3b830a9c LT |
187 | memcpy(to, from, n); |
188 | zero_buffer(tty, from, n); | |
72586c60 LA |
189 | } |
190 | ||
24a89d1c | 191 | /** |
98629663 JS |
192 | * n_tty_kick_worker - start input worker (if required) |
193 | * @tty: terminal | |
24a89d1c | 194 | * |
98629663 | 195 | * Re-schedules the flip buffer work if it may have stopped. |
24a89d1c | 196 | * |
98629663 JS |
197 | * Locking: |
198 | * * Caller holds exclusive %termios_rwsem, or | |
199 | * * n_tty_read()/consumer path: | |
200 | * holds non-exclusive %termios_rwsem | |
24a89d1c | 201 | */ |
2c5dc464 | 202 | static void n_tty_kick_worker(struct tty_struct *tty) |
7879a9f9 | 203 | { |
24a89d1c PH |
204 | struct n_tty_data *ldata = tty->disc_data; |
205 | ||
2c5dc464 PH |
206 | /* Did the input worker stop? Restart it */ |
207 | if (unlikely(ldata->no_room)) { | |
24a89d1c PH |
208 | ldata->no_room = 0; |
209 | ||
ecbbfd44 | 210 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 211 | "scheduling with invalid itty\n"); |
21622939 PH |
212 | /* see if ldisc has been killed - if so, this means that |
213 | * even though the ldisc has been halted and ->buf.work | |
214 | * cancelled, ->buf.work is about to be rescheduled | |
215 | */ | |
216 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
217 | "scheduling buffer work for halted ldisc\n"); | |
e176058f | 218 | tty_buffer_restart_work(tty->port); |
ecbbfd44 | 219 | } |
55db4c64 LT |
220 | } |
221 | ||
9a4aec2d PH |
222 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
223 | { | |
224 | struct n_tty_data *ldata = tty->disc_data; | |
225 | ssize_t n = 0; | |
226 | ||
227 | if (!ldata->icanon) | |
70aca71f | 228 | n = ldata->commit_head - ldata->read_tail; |
9a4aec2d PH |
229 | else |
230 | n = ldata->canon_head - ldata->read_tail; | |
231 | return n; | |
232 | } | |
233 | ||
ee0bab83 | 234 | /** |
98629663 JS |
235 | * n_tty_write_wakeup - asynchronous I/O notifier |
236 | * @tty: tty device | |
ee0bab83 | 237 | * |
98629663 JS |
238 | * Required for the ptys, serial driver etc. since processes that attach |
239 | * themselves to the master and rely on ASYNC IO must be woken up. | |
ee0bab83 | 240 | */ |
ee0bab83 PH |
241 | static void n_tty_write_wakeup(struct tty_struct *tty) |
242 | { | |
7bccc365 PH |
243 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
244 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
ee0bab83 PH |
245 | } |
246 | ||
4a23a4df | 247 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 248 | { |
a342846f PH |
249 | struct n_tty_data *ldata = tty->disc_data; |
250 | ||
6367ca72 PH |
251 | /* |
252 | * Check the remaining room for the input canonicalization | |
253 | * mode. We don't want to throttle the driver if we're in | |
254 | * canonical mode and don't have a newline yet! | |
255 | */ | |
a342846f PH |
256 | if (ldata->icanon && ldata->canon_head == ldata->read_tail) |
257 | return; | |
258 | ||
6367ca72 PH |
259 | while (1) { |
260 | int throttled; | |
261 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
5e28cca1 | 262 | if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE) |
6367ca72 PH |
263 | break; |
264 | throttled = tty_throttle_safe(tty); | |
265 | if (!throttled) | |
266 | break; | |
267 | } | |
268 | __tty_set_flow_change(tty, 0); | |
269 | } | |
270 | ||
4b293492 | 271 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 272 | { |
6d27a63c | 273 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { |
3afb1b39 PH |
274 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) |
275 | return; | |
2c5dc464 | 276 | n_tty_kick_worker(tty); |
6d27a63c | 277 | tty_wakeup(tty->link); |
3afb1b39 PH |
278 | return; |
279 | } | |
280 | ||
6367ca72 PH |
281 | /* If there is enough space in the read buffer now, let the |
282 | * low-level driver know. We use chars_in_buffer() to | |
283 | * check the buffer, as it now knows about canonical mode. | |
284 | * Otherwise, if the driver is throttled and the line is | |
285 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
286 | * we won't get any more characters. | |
287 | */ | |
288 | ||
289 | while (1) { | |
290 | int unthrottled; | |
291 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
292 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
293 | break; | |
2c5dc464 | 294 | n_tty_kick_worker(tty); |
6367ca72 PH |
295 | unthrottled = tty_unthrottle_safe(tty); |
296 | if (!unthrottled) | |
297 | break; | |
298 | } | |
299 | __tty_set_flow_change(tty, 0); | |
300 | } | |
301 | ||
17b82060 | 302 | /** |
98629663 JS |
303 | * put_tty_queue - add character to tty |
304 | * @c: character | |
305 | * @ldata: n_tty data | |
17b82060 | 306 | * |
98629663 | 307 | * Add a character to the tty read_buf queue. |
6d76bd26 | 308 | * |
98629663 JS |
309 | * Locking: |
310 | * * n_tty_receive_buf()/producer path: | |
311 | * caller holds non-exclusive %termios_rwsem | |
17b82060 | 312 | */ |
19e2ad6a | 313 | static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 314 | { |
8bfbe2de CR |
315 | *read_buf_addr(ldata, ldata->read_head) = c; |
316 | ldata->read_head++; | |
1da177e4 LT |
317 | } |
318 | ||
1da177e4 | 319 | /** |
98629663 JS |
320 | * reset_buffer_flags - reset buffer state |
321 | * @ldata: line disc data to reset | |
1da177e4 | 322 | * |
98629663 JS |
323 | * Reset the read buffer counters and clear the flags. Called from |
324 | * n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 325 | * |
98629663 JS |
326 | * Locking: |
327 | * * caller holds exclusive %termios_rwsem, or | |
328 | * * (locking is not required) | |
1da177e4 | 329 | */ |
b66f4fa5 | 330 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 331 | { |
a73d3d69 | 332 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
70aca71f | 333 | ldata->commit_head = 0; |
40d5e090 | 334 | ldata->line_start = 0; |
a88a69c9 | 335 | |
a73d3d69 | 336 | ldata->erasing = 0; |
3fe780b3 | 337 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 | 338 | ldata->push = 0; |
6bb6fa69 IJ |
339 | |
340 | ldata->lookahead_count = 0; | |
1da177e4 LT |
341 | } |
342 | ||
a30737ab PH |
343 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
344 | { | |
345 | unsigned long flags; | |
346 | ||
64d608db JS |
347 | if (tty->link->ctrl.packet) { |
348 | spin_lock_irqsave(&tty->ctrl.lock, flags); | |
349 | tty->ctrl.pktstatus |= TIOCPKT_FLUSHREAD; | |
350 | spin_unlock_irqrestore(&tty->ctrl.lock, flags); | |
e81107d4 | 351 | wake_up_interruptible(&tty->link->read_wait); |
a30737ab | 352 | } |
a30737ab PH |
353 | } |
354 | ||
1da177e4 | 355 | /** |
98629663 JS |
356 | * n_tty_flush_buffer - clean input queue |
357 | * @tty: terminal device | |
1da177e4 | 358 | * |
98629663 JS |
359 | * Flush the input buffer. Called when the tty layer wants the buffer flushed |
360 | * (eg at hangup) or when the %N_TTY line discipline internally has to clean | |
361 | * the pending queue (for example some signals). | |
1da177e4 | 362 | * |
98629663 JS |
363 | * Holds %termios_rwsem to exclude producer/consumer while buffer indices are |
364 | * reset. | |
6d76bd26 | 365 | * |
98629663 | 366 | * Locking: %ctrl.lock, exclusive %termios_rwsem |
1da177e4 | 367 | */ |
4edf1827 | 368 | static void n_tty_flush_buffer(struct tty_struct *tty) |
1da177e4 | 369 | { |
6d76bd26 | 370 | down_write(&tty->termios_rwsem); |
b66f4fa5 | 371 | reset_buffer_flags(tty->disc_data); |
2c5dc464 | 372 | n_tty_kick_worker(tty); |
4edf1827 | 373 | |
a30737ab PH |
374 | if (tty->link) |
375 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 376 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
377 | } |
378 | ||
1da177e4 | 379 | /** |
98629663 JS |
380 | * is_utf8_continuation - utf8 multibyte check |
381 | * @c: byte to check | |
1da177e4 | 382 | * |
98629663 JS |
383 | * Returns: true if the utf8 character @c is a multibyte continuation |
384 | * character. We use this to correctly compute the on-screen size of the | |
385 | * character when printing. | |
1da177e4 | 386 | */ |
1da177e4 LT |
387 | static inline int is_utf8_continuation(unsigned char c) |
388 | { | |
389 | return (c & 0xc0) == 0x80; | |
390 | } | |
391 | ||
392 | /** | |
98629663 JS |
393 | * is_continuation - multibyte check |
394 | * @c: byte to check | |
395 | * @tty: terminal device | |
1da177e4 | 396 | * |
98629663 JS |
397 | * Returns: true if the utf8 character @c is a multibyte continuation character |
398 | * and the terminal is in unicode mode. | |
1da177e4 | 399 | */ |
1da177e4 LT |
400 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
401 | { | |
402 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
403 | } | |
404 | ||
405 | /** | |
98629663 JS |
406 | * do_output_char - output one character |
407 | * @c: character (or partial unicode symbol) | |
408 | * @tty: terminal device | |
409 | * @space: space available in tty driver write buffer | |
1da177e4 | 410 | * |
98629663 JS |
411 | * This is a helper function that handles one output character (including |
412 | * special characters like TAB, CR, LF, etc.), doing OPOST processing and | |
413 | * putting the results in the tty driver's write buffer. | |
a88a69c9 | 414 | * |
98629663 JS |
415 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY and NLDLY. |
416 | * They simply aren't relevant in the world today. If you ever need them, add | |
417 | * them here. | |
1da177e4 | 418 | * |
98629663 | 419 | * Returns: the number of bytes of buffer space used or -1 if no space left. |
a88a69c9 | 420 | * |
98629663 JS |
421 | * Locking: should be called under the %output_lock to protect the column state |
422 | * and space left in the buffer. | |
1da177e4 | 423 | */ |
a88a69c9 | 424 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 425 | { |
53c5ee2c | 426 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 427 | int spaces; |
1da177e4 | 428 | |
1da177e4 LT |
429 | if (!space) |
430 | return -1; | |
300a6204 | 431 | |
a88a69c9 JP |
432 | switch (c) { |
433 | case '\n': | |
434 | if (O_ONLRET(tty)) | |
53c5ee2c | 435 | ldata->column = 0; |
a88a69c9 JP |
436 | if (O_ONLCR(tty)) { |
437 | if (space < 2) | |
438 | return -1; | |
ba2e68ac | 439 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 440 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
441 | return 2; |
442 | } | |
ba2e68ac | 443 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
444 | break; |
445 | case '\r': | |
53c5ee2c | 446 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
447 | return 0; |
448 | if (O_OCRNL(tty)) { | |
449 | c = '\n'; | |
450 | if (O_ONLRET(tty)) | |
ba2e68ac | 451 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 452 | break; |
a88a69c9 | 453 | } |
ba2e68ac | 454 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
455 | break; |
456 | case '\t': | |
53c5ee2c | 457 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
458 | if (O_TABDLY(tty) == XTABS) { |
459 | if (space < spaces) | |
460 | return -1; | |
53c5ee2c | 461 | ldata->column += spaces; |
a88a69c9 JP |
462 | tty->ops->write(tty, " ", spaces); |
463 | return spaces; | |
1da177e4 | 464 | } |
53c5ee2c | 465 | ldata->column += spaces; |
a88a69c9 JP |
466 | break; |
467 | case '\b': | |
53c5ee2c JS |
468 | if (ldata->column > 0) |
469 | ldata->column--; | |
a88a69c9 JP |
470 | break; |
471 | default: | |
a59c0d6f JP |
472 | if (!iscntrl(c)) { |
473 | if (O_OLCUC(tty)) | |
474 | c = toupper(c); | |
475 | if (!is_continuation(c, tty)) | |
53c5ee2c | 476 | ldata->column++; |
a59c0d6f | 477 | } |
a88a69c9 | 478 | break; |
1da177e4 | 479 | } |
a88a69c9 | 480 | |
f34d7a5b | 481 | tty_put_char(tty, c); |
a88a69c9 JP |
482 | return 1; |
483 | } | |
484 | ||
485 | /** | |
98629663 JS |
486 | * process_output - output post processor |
487 | * @c: character (or partial unicode symbol) | |
488 | * @tty: terminal device | |
489 | * | |
490 | * Output one character with OPOST processing. | |
a88a69c9 | 491 | * |
98629663 JS |
492 | * Returns: -1 when the output device is full and the character must be |
493 | * retried. | |
a88a69c9 | 494 | * |
98629663 JS |
495 | * Locking: %output_lock to protect column state and space left (also, this is |
496 | *called from n_tty_write() under the tty layer write lock). | |
a88a69c9 | 497 | */ |
a88a69c9 JP |
498 | static int process_output(unsigned char c, struct tty_struct *tty) |
499 | { | |
bddc7152 | 500 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
501 | int space, retval; |
502 | ||
bddc7152 | 503 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
504 | |
505 | space = tty_write_room(tty); | |
506 | retval = do_output_char(c, tty, space); | |
507 | ||
bddc7152 | 508 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
509 | if (retval < 0) |
510 | return -1; | |
511 | else | |
512 | return 0; | |
1da177e4 LT |
513 | } |
514 | ||
515 | /** | |
98629663 JS |
516 | * process_output_block - block post processor |
517 | * @tty: terminal device | |
518 | * @buf: character buffer | |
519 | * @nr: number of bytes to output | |
520 | * | |
521 | * Output a block of characters with OPOST processing. | |
522 | * | |
523 | * This path is used to speed up block console writes, among other things when | |
524 | * processing blocks of output data. It handles only the simple cases normally | |
525 | * found and helps to generate blocks of symbols for the console driver and | |
526 | * thus improve performance. | |
527 | * | |
528 | * Returns: the number of characters output. | |
529 | * | |
530 | * Locking: %output_lock to protect column state and space left (also, this is | |
531 | * called from n_tty_write() under the tty layer write lock). | |
1da177e4 | 532 | */ |
a88a69c9 JP |
533 | static ssize_t process_output_block(struct tty_struct *tty, |
534 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 535 | { |
53c5ee2c | 536 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 537 | int space; |
bbd20759 | 538 | int i; |
1da177e4 LT |
539 | const unsigned char *cp; |
540 | ||
bddc7152 | 541 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 542 | |
f34d7a5b | 543 | space = tty_write_room(tty); |
9ef8927f | 544 | if (space <= 0) { |
bddc7152 | 545 | mutex_unlock(&ldata->output_lock); |
9ef8927f | 546 | return space; |
a88a69c9 | 547 | } |
1da177e4 LT |
548 | if (nr > space) |
549 | nr = space; | |
550 | ||
551 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
552 | unsigned char c = *cp; |
553 | ||
554 | switch (c) { | |
1da177e4 LT |
555 | case '\n': |
556 | if (O_ONLRET(tty)) | |
53c5ee2c | 557 | ldata->column = 0; |
1da177e4 LT |
558 | if (O_ONLCR(tty)) |
559 | goto break_out; | |
ba2e68ac | 560 | ldata->canon_column = ldata->column; |
1da177e4 LT |
561 | break; |
562 | case '\r': | |
53c5ee2c | 563 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
564 | goto break_out; |
565 | if (O_OCRNL(tty)) | |
566 | goto break_out; | |
ba2e68ac | 567 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
568 | break; |
569 | case '\t': | |
570 | goto break_out; | |
571 | case '\b': | |
53c5ee2c JS |
572 | if (ldata->column > 0) |
573 | ldata->column--; | |
1da177e4 LT |
574 | break; |
575 | default: | |
a59c0d6f JP |
576 | if (!iscntrl(c)) { |
577 | if (O_OLCUC(tty)) | |
578 | goto break_out; | |
579 | if (!is_continuation(c, tty)) | |
53c5ee2c | 580 | ldata->column++; |
a59c0d6f | 581 | } |
1da177e4 LT |
582 | break; |
583 | } | |
584 | } | |
585 | break_out: | |
f34d7a5b | 586 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 587 | |
bddc7152 | 588 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
589 | return i; |
590 | } | |
591 | ||
a88a69c9 | 592 | /** |
98629663 JS |
593 | * __process_echoes - write pending echo characters |
594 | * @tty: terminal device | |
a88a69c9 | 595 | * |
98629663 JS |
596 | * Write previously buffered echo (and other ldisc-generated) characters to the |
597 | * tty. | |
a88a69c9 | 598 | * |
98629663 JS |
599 | * Characters generated by the ldisc (including echoes) need to be buffered |
600 | * because the driver's write buffer can fill during heavy program output. | |
601 | * Echoing straight to the driver will often fail under these conditions, | |
602 | * causing lost characters and resulting mismatches of ldisc state information. | |
a88a69c9 | 603 | * |
98629663 JS |
604 | * Since the ldisc state must represent the characters actually sent to the |
605 | * driver at the time of the write, operations like certain changes in column | |
606 | * state are also saved in the buffer and executed here. | |
a88a69c9 | 607 | * |
98629663 JS |
608 | * A circular fifo buffer is used so that the most recent characters are |
609 | * prioritized. Also, when control characters are echoed with a prefixed "^", | |
610 | * the pair is treated atomically and thus not separated. | |
a88a69c9 | 611 | * |
98629663 | 612 | * Locking: callers must hold %output_lock. |
a88a69c9 | 613 | */ |
bc5b1ec5 | 614 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 615 | { |
53c5ee2c | 616 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 617 | int space, old_space; |
addaebcc | 618 | size_t tail; |
a88a69c9 | 619 | unsigned char c; |
a88a69c9 | 620 | |
bc5b1ec5 | 621 | old_space = space = tty_write_room(tty); |
a88a69c9 | 622 | |
addaebcc | 623 | tail = ldata->echo_tail; |
ebec3f8f | 624 | while (MASK(ldata->echo_commit) != MASK(tail)) { |
addaebcc | 625 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
626 | if (c == ECHO_OP_START) { |
627 | unsigned char op; | |
a88a69c9 JP |
628 | int no_space_left = 0; |
629 | ||
ebec3f8f TH |
630 | /* |
631 | * Since add_echo_byte() is called without holding | |
632 | * output_lock, we might see only portion of multi-byte | |
633 | * operation. | |
634 | */ | |
635 | if (MASK(ldata->echo_commit) == MASK(tail + 1)) | |
636 | goto not_yet_stored; | |
a88a69c9 JP |
637 | /* |
638 | * If the buffer byte is the start of a multi-byte | |
639 | * operation, get the next byte, which is either the | |
640 | * op code or a control character value. | |
641 | */ | |
addaebcc | 642 | op = echo_buf(ldata, tail + 1); |
300a6204 | 643 | |
a88a69c9 | 644 | switch (op) { |
e24cd4e6 | 645 | case ECHO_OP_ERASE_TAB: { |
a88a69c9 JP |
646 | unsigned int num_chars, num_bs; |
647 | ||
ebec3f8f TH |
648 | if (MASK(ldata->echo_commit) == MASK(tail + 2)) |
649 | goto not_yet_stored; | |
addaebcc | 650 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
651 | |
652 | /* | |
653 | * Determine how many columns to go back | |
654 | * in order to erase the tab. | |
655 | * This depends on the number of columns | |
656 | * used by other characters within the tab | |
657 | * area. If this (modulo 8) count is from | |
658 | * the start of input rather than from a | |
659 | * previous tab, we offset by canon column. | |
660 | * Otherwise, tab spacing is normal. | |
661 | */ | |
662 | if (!(num_chars & 0x80)) | |
ba2e68ac | 663 | num_chars += ldata->canon_column; |
a88a69c9 JP |
664 | num_bs = 8 - (num_chars & 7); |
665 | ||
666 | if (num_bs > space) { | |
667 | no_space_left = 1; | |
668 | break; | |
669 | } | |
670 | space -= num_bs; | |
671 | while (num_bs--) { | |
672 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
673 | if (ldata->column > 0) |
674 | ldata->column--; | |
a88a69c9 | 675 | } |
addaebcc | 676 | tail += 3; |
a88a69c9 | 677 | break; |
e24cd4e6 | 678 | } |
a88a69c9 | 679 | case ECHO_OP_SET_CANON_COL: |
ba2e68ac | 680 | ldata->canon_column = ldata->column; |
addaebcc | 681 | tail += 2; |
a88a69c9 JP |
682 | break; |
683 | ||
684 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
685 | if (ldata->column > 0) |
686 | ldata->column--; | |
addaebcc | 687 | tail += 2; |
a88a69c9 JP |
688 | break; |
689 | ||
690 | case ECHO_OP_START: | |
691 | /* This is an escaped echo op start code */ | |
692 | if (!space) { | |
693 | no_space_left = 1; | |
694 | break; | |
695 | } | |
696 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 697 | ldata->column++; |
a88a69c9 | 698 | space--; |
addaebcc | 699 | tail += 2; |
a88a69c9 JP |
700 | break; |
701 | ||
702 | default: | |
a88a69c9 | 703 | /* |
62b26358 JP |
704 | * If the op is not a special byte code, |
705 | * it is a ctrl char tagged to be echoed | |
706 | * as "^X" (where X is the letter | |
707 | * representing the control char). | |
708 | * Note that we must ensure there is | |
709 | * enough space for the whole ctrl pair. | |
710 | * | |
a88a69c9 | 711 | */ |
62b26358 JP |
712 | if (space < 2) { |
713 | no_space_left = 1; | |
714 | break; | |
715 | } | |
716 | tty_put_char(tty, '^'); | |
717 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 718 | ldata->column += 2; |
62b26358 | 719 | space -= 2; |
addaebcc | 720 | tail += 2; |
a88a69c9 JP |
721 | } |
722 | ||
723 | if (no_space_left) | |
724 | break; | |
725 | } else { | |
582f5590 | 726 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
727 | int retval = do_output_char(c, tty, space); |
728 | if (retval < 0) | |
729 | break; | |
730 | space -= retval; | |
731 | } else { | |
732 | if (!space) | |
733 | break; | |
734 | tty_put_char(tty, c); | |
735 | space -= 1; | |
736 | } | |
addaebcc | 737 | tail += 1; |
a88a69c9 | 738 | } |
a88a69c9 JP |
739 | } |
740 | ||
cbfd0340 PH |
741 | /* If the echo buffer is nearly full (so that the possibility exists |
742 | * of echo overrun before the next commit), then discard enough | |
743 | * data at the tail to prevent a subsequent overrun */ | |
ebec3f8f TH |
744 | while (ldata->echo_commit > tail && |
745 | ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 746 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 747 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
748 | tail += 3; |
749 | else | |
750 | tail += 2; | |
751 | } else | |
752 | tail++; | |
753 | } | |
754 | ||
ebec3f8f | 755 | not_yet_stored: |
addaebcc | 756 | ldata->echo_tail = tail; |
bc5b1ec5 | 757 | return old_space - space; |
019ebdf9 PH |
758 | } |
759 | ||
760 | static void commit_echoes(struct tty_struct *tty) | |
761 | { | |
762 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 763 | size_t nr, old, echoed; |
cbfd0340 PH |
764 | size_t head; |
765 | ||
ebec3f8f | 766 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 767 | head = ldata->echo_head; |
1075a6e2 | 768 | ldata->echo_mark = head; |
cbfd0340 PH |
769 | old = ldata->echo_commit - ldata->echo_tail; |
770 | ||
771 | /* Process committed echoes if the accumulated # of bytes | |
772 | * is over the threshold (and try again each time another | |
773 | * block is accumulated) */ | |
774 | nr = head - ldata->echo_tail; | |
ebec3f8f TH |
775 | if (nr < ECHO_COMMIT_WATERMARK || |
776 | (nr % ECHO_BLOCK > old % ECHO_BLOCK)) { | |
777 | mutex_unlock(&ldata->output_lock); | |
cbfd0340 | 778 | return; |
ebec3f8f | 779 | } |
a88a69c9 | 780 | |
cbfd0340 | 781 | ldata->echo_commit = head; |
bc5b1ec5 | 782 | echoed = __process_echoes(tty); |
bddc7152 | 783 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 784 | |
bc5b1ec5 | 785 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
786 | tty->ops->flush_chars(tty); |
787 | } | |
788 | ||
019ebdf9 | 789 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
790 | { |
791 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 792 | size_t echoed; |
17bd7907 | 793 | |
e2613be5 | 794 | if (ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
795 | return; |
796 | ||
797 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 798 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 799 | echoed = __process_echoes(tty); |
019ebdf9 PH |
800 | mutex_unlock(&ldata->output_lock); |
801 | ||
bc5b1ec5 | 802 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 803 | tty->ops->flush_chars(tty); |
17bd7907 PH |
804 | } |
805 | ||
1075a6e2 | 806 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
807 | static void flush_echoes(struct tty_struct *tty) |
808 | { | |
809 | struct n_tty_data *ldata = tty->disc_data; | |
810 | ||
39434abd PH |
811 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
812 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
813 | return; |
814 | ||
815 | mutex_lock(&ldata->output_lock); | |
816 | ldata->echo_commit = ldata->echo_head; | |
817 | __process_echoes(tty); | |
818 | mutex_unlock(&ldata->output_lock); | |
819 | } | |
820 | ||
a88a69c9 | 821 | /** |
98629663 JS |
822 | * add_echo_byte - add a byte to the echo buffer |
823 | * @c: unicode byte to echo | |
824 | * @ldata: n_tty data | |
a88a69c9 | 825 | * |
98629663 | 826 | * Add a character or operation byte to the echo buffer. |
a88a69c9 | 827 | */ |
cbfd0340 | 828 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 829 | { |
ebec3f8f TH |
830 | *echo_buf_addr(ldata, ldata->echo_head) = c; |
831 | smp_wmb(); /* Matches smp_rmb() in echo_buf(). */ | |
832 | ldata->echo_head++; | |
a88a69c9 JP |
833 | } |
834 | ||
835 | /** | |
98629663 JS |
836 | * echo_move_back_col - add operation to move back a column |
837 | * @ldata: n_tty data | |
a88a69c9 | 838 | * |
98629663 | 839 | * Add an operation to the echo buffer to move back one column. |
a88a69c9 | 840 | */ |
57c94121 | 841 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 842 | { |
57c94121 JS |
843 | add_echo_byte(ECHO_OP_START, ldata); |
844 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
845 | } |
846 | ||
847 | /** | |
98629663 JS |
848 | * echo_set_canon_col - add operation to set the canon column |
849 | * @ldata: n_tty data | |
a88a69c9 | 850 | * |
98629663 JS |
851 | * Add an operation to the echo buffer to set the canon column to the current |
852 | * column. | |
a88a69c9 | 853 | */ |
57c94121 | 854 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 855 | { |
57c94121 JS |
856 | add_echo_byte(ECHO_OP_START, ldata); |
857 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
858 | } |
859 | ||
860 | /** | |
98629663 JS |
861 | * echo_erase_tab - add operation to erase a tab |
862 | * @num_chars: number of character columns already used | |
863 | * @after_tab: true if num_chars starts after a previous tab | |
864 | * @ldata: n_tty data | |
865 | * | |
866 | * Add an operation to the echo buffer to erase a tab. | |
867 | * | |
868 | * Called by the eraser function, which knows how many character columns have | |
869 | * been used since either a previous tab or the start of input. This | |
870 | * information will be used later, along with canon column (if applicable), to | |
871 | * go back the correct number of columns. | |
a88a69c9 | 872 | */ |
a88a69c9 | 873 | static void echo_erase_tab(unsigned int num_chars, int after_tab, |
57c94121 | 874 | struct n_tty_data *ldata) |
a88a69c9 | 875 | { |
57c94121 JS |
876 | add_echo_byte(ECHO_OP_START, ldata); |
877 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
878 | |
879 | /* We only need to know this modulo 8 (tab spacing) */ | |
880 | num_chars &= 7; | |
881 | ||
882 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
883 | if (after_tab) | |
884 | num_chars |= 0x80; | |
300a6204 | 885 | |
57c94121 | 886 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
887 | } |
888 | ||
889 | /** | |
98629663 JS |
890 | * echo_char_raw - echo a character raw |
891 | * @c: unicode byte to echo | |
892 | * @ldata: line disc data | |
a88a69c9 | 893 | * |
98629663 JS |
894 | * Echo user input back onto the screen. This must be called only when |
895 | * L_ECHO(tty) is true. Called from the &tty_driver.receive_buf() path. | |
a88a69c9 | 896 | * |
98629663 | 897 | * This variant does not treat control characters specially. |
a88a69c9 | 898 | */ |
57c94121 | 899 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 900 | { |
a88a69c9 | 901 | if (c == ECHO_OP_START) { |
57c94121 JS |
902 | add_echo_byte(ECHO_OP_START, ldata); |
903 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 904 | } else { |
57c94121 | 905 | add_echo_byte(c, ldata); |
a88a69c9 | 906 | } |
a88a69c9 | 907 | } |
1da177e4 | 908 | |
1da177e4 | 909 | /** |
98629663 JS |
910 | * echo_char - echo a character |
911 | * @c: unicode byte to echo | |
912 | * @tty: terminal device | |
1da177e4 | 913 | * |
98629663 JS |
914 | * Echo user input back onto the screen. This must be called only when |
915 | * L_ECHO(tty) is true. Called from the &tty_driver.receive_buf() path. | |
17b82060 | 916 | * |
98629663 JS |
917 | * This variant tags control characters to be echoed as "^X" (where X is the |
918 | * letter representing the control char). | |
1da177e4 | 919 | */ |
1da177e4 LT |
920 | static void echo_char(unsigned char c, struct tty_struct *tty) |
921 | { | |
bddc7152 JS |
922 | struct n_tty_data *ldata = tty->disc_data; |
923 | ||
a88a69c9 | 924 | if (c == ECHO_OP_START) { |
57c94121 JS |
925 | add_echo_byte(ECHO_OP_START, ldata); |
926 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 927 | } else { |
62b26358 | 928 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
929 | add_echo_byte(ECHO_OP_START, ldata); |
930 | add_echo_byte(c, ldata); | |
a88a69c9 | 931 | } |
1da177e4 LT |
932 | } |
933 | ||
17b82060 | 934 | /** |
98629663 JS |
935 | * finish_erasing - complete erase |
936 | * @ldata: n_tty data | |
17b82060 | 937 | */ |
57c94121 | 938 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 939 | { |
53c5ee2c | 940 | if (ldata->erasing) { |
57c94121 | 941 | echo_char_raw('/', ldata); |
53c5ee2c | 942 | ldata->erasing = 0; |
1da177e4 LT |
943 | } |
944 | } | |
945 | ||
946 | /** | |
98629663 JS |
947 | * eraser - handle erase function |
948 | * @c: character input | |
949 | * @tty: terminal device | |
1da177e4 | 950 | * |
98629663 JS |
951 | * Perform erase and necessary output when an erase character is present in the |
952 | * stream from the driver layer. Handles the complexities of UTF-8 multibyte | |
953 | * symbols. | |
17b82060 | 954 | * |
98629663 JS |
955 | * Locking: n_tty_receive_buf()/producer path: |
956 | * caller holds non-exclusive %termios_rwsem | |
1da177e4 | 957 | */ |
1da177e4 LT |
958 | static void eraser(unsigned char c, struct tty_struct *tty) |
959 | { | |
53c5ee2c | 960 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 961 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
962 | size_t head; |
963 | size_t cnt; | |
964 | int seen_alnums; | |
1da177e4 | 965 | |
ba2e68ac | 966 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 967 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
968 | return; |
969 | } | |
970 | if (c == ERASE_CHAR(tty)) | |
971 | kill_type = ERASE; | |
972 | else if (c == WERASE_CHAR(tty)) | |
973 | kill_type = WERASE; | |
974 | else { | |
975 | if (!L_ECHO(tty)) { | |
ba2e68ac | 976 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
977 | return; |
978 | } | |
979 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 980 | ldata->read_head = ldata->canon_head; |
57c94121 | 981 | finish_erasing(ldata); |
1da177e4 LT |
982 | echo_char(KILL_CHAR(tty), tty); |
983 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
984 | if (L_ECHOK(tty)) | |
57c94121 | 985 | echo_char_raw('\n', ldata); |
1da177e4 LT |
986 | return; |
987 | } | |
988 | kill_type = KILL; | |
989 | } | |
990 | ||
991 | seen_alnums = 0; | |
3d63b7e4 | 992 | while (MASK(ldata->read_head) != MASK(ldata->canon_head)) { |
ba2e68ac | 993 | head = ldata->read_head; |
1da177e4 LT |
994 | |
995 | /* erase a single possibly multibyte character */ | |
996 | do { | |
bc5a5e3f PH |
997 | head--; |
998 | c = read_buf(ldata, head); | |
3d63b7e4 TH |
999 | } while (is_continuation(c, tty) && |
1000 | MASK(head) != MASK(ldata->canon_head)); | |
1da177e4 LT |
1001 | |
1002 | /* do not partially erase */ | |
1003 | if (is_continuation(c, tty)) | |
1004 | break; | |
1005 | ||
1006 | if (kill_type == WERASE) { | |
1007 | /* Equivalent to BSD's ALTWERASE. */ | |
1008 | if (isalnum(c) || c == '_') | |
1009 | seen_alnums++; | |
1010 | else if (seen_alnums) | |
1011 | break; | |
1012 | } | |
bc5a5e3f | 1013 | cnt = ldata->read_head - head; |
ba2e68ac | 1014 | ldata->read_head = head; |
1da177e4 LT |
1015 | if (L_ECHO(tty)) { |
1016 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1017 | if (!ldata->erasing) { |
57c94121 | 1018 | echo_char_raw('\\', ldata); |
53c5ee2c | 1019 | ldata->erasing = 1; |
1da177e4 LT |
1020 | } |
1021 | /* if cnt > 1, output a multi-byte character */ | |
1022 | echo_char(c, tty); | |
1023 | while (--cnt > 0) { | |
bc5a5e3f PH |
1024 | head++; |
1025 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1026 | echo_move_back_col(ldata); |
1da177e4 LT |
1027 | } |
1028 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1029 | echo_char(ERASE_CHAR(tty), tty); | |
1030 | } else if (c == '\t') { | |
a88a69c9 JP |
1031 | unsigned int num_chars = 0; |
1032 | int after_tab = 0; | |
bc5a5e3f | 1033 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1034 | |
1035 | /* | |
1036 | * Count the columns used for characters | |
1037 | * since the start of input or after a | |
1038 | * previous tab. | |
1039 | * This info is used to go back the correct | |
1040 | * number of columns. | |
1041 | */ | |
3d63b7e4 | 1042 | while (MASK(tail) != MASK(ldata->canon_head)) { |
bc5a5e3f PH |
1043 | tail--; |
1044 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1045 | if (c == '\t') { |
1046 | after_tab = 1; | |
1047 | break; | |
300a6204 | 1048 | } else if (iscntrl(c)) { |
1da177e4 | 1049 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1050 | num_chars += 2; |
1051 | } else if (!is_continuation(c, tty)) { | |
1052 | num_chars++; | |
1053 | } | |
1da177e4 | 1054 | } |
57c94121 | 1055 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1056 | } else { |
1057 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1058 | echo_char_raw('\b', ldata); |
1059 | echo_char_raw(' ', ldata); | |
1060 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1061 | } |
1062 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1063 | echo_char_raw('\b', ldata); |
1064 | echo_char_raw(' ', ldata); | |
1065 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1066 | } |
1067 | } | |
1068 | } | |
1069 | if (kill_type == ERASE) | |
1070 | break; | |
1071 | } | |
ba2e68ac | 1072 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1073 | finish_erasing(ldata); |
1da177e4 LT |
1074 | } |
1075 | ||
c66453ce JS |
1076 | |
1077 | static void __isig(int sig, struct tty_struct *tty) | |
1078 | { | |
1079 | struct pid *tty_pgrp = tty_get_pgrp(tty); | |
1080 | if (tty_pgrp) { | |
1081 | kill_pgrp(tty_pgrp, sig, 1); | |
1082 | put_pid(tty_pgrp); | |
1083 | } | |
1084 | } | |
1085 | ||
1da177e4 | 1086 | /** |
98629663 JS |
1087 | * isig - handle the ISIG optio |
1088 | * @sig: signal | |
1089 | * @tty: terminal | |
1da177e4 | 1090 | * |
98629663 JS |
1091 | * Called when a signal is being sent due to terminal input. Called from the |
1092 | * &tty_driver.receive_buf() path, so serialized. | |
17b82060 | 1093 | * |
98629663 JS |
1094 | * Performs input and output flush if !NOFLSH. In this context, the echo |
1095 | * buffer is 'output'. The signal is processed first to alert any current | |
1096 | * readers or writers to discontinue and exit their i/o loops. | |
d2b6f447 | 1097 | * |
98629663 | 1098 | * Locking: %ctrl.lock |
1da177e4 | 1099 | */ |
3b19e032 PH |
1100 | static void isig(int sig, struct tty_struct *tty) |
1101 | { | |
1102 | struct n_tty_data *ldata = tty->disc_data; | |
1103 | ||
1104 | if (L_NOFLSH(tty)) { | |
1105 | /* signal only */ | |
1106 | __isig(sig, tty); | |
1107 | ||
1108 | } else { /* signal and flush */ | |
d2b6f447 PH |
1109 | up_read(&tty->termios_rwsem); |
1110 | down_write(&tty->termios_rwsem); | |
1111 | ||
3b19e032 PH |
1112 | __isig(sig, tty); |
1113 | ||
d2b6f447 PH |
1114 | /* clear echo buffer */ |
1115 | mutex_lock(&ldata->output_lock); | |
1116 | ldata->echo_head = ldata->echo_tail = 0; | |
1117 | ldata->echo_mark = ldata->echo_commit = 0; | |
1118 | mutex_unlock(&ldata->output_lock); | |
1119 | ||
1120 | /* clear output buffer */ | |
1121 | tty_driver_flush_buffer(tty); | |
1122 | ||
1123 | /* clear input buffer */ | |
1124 | reset_buffer_flags(tty->disc_data); | |
1125 | ||
1126 | /* notify pty master of flush */ | |
1127 | if (tty->link) | |
1128 | n_tty_packet_mode_flush(tty); | |
1129 | ||
1130 | up_write(&tty->termios_rwsem); | |
1131 | down_read(&tty->termios_rwsem); | |
1132 | } | |
1da177e4 LT |
1133 | } |
1134 | ||
1135 | /** | |
98629663 JS |
1136 | * n_tty_receive_break - handle break |
1137 | * @tty: terminal | |
1da177e4 | 1138 | * |
98629663 JS |
1139 | * An RS232 break event has been hit in the incoming bitstream. This can cause |
1140 | * a variety of events depending upon the termios settings. | |
1da177e4 | 1141 | * |
98629663 JS |
1142 | * Locking: n_tty_receive_buf()/producer path: |
1143 | * caller holds non-exclusive termios_rwsem | |
6d76bd26 | 1144 | * |
98629663 | 1145 | * Note: may get exclusive %termios_rwsem if flushing input buffer |
1da177e4 | 1146 | */ |
4b293492 | 1147 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1148 | { |
57c94121 JS |
1149 | struct n_tty_data *ldata = tty->disc_data; |
1150 | ||
1da177e4 LT |
1151 | if (I_IGNBRK(tty)) |
1152 | return; | |
1153 | if (I_BRKINT(tty)) { | |
8c985d18 | 1154 | isig(SIGINT, tty); |
1da177e4 LT |
1155 | return; |
1156 | } | |
1157 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1158 | put_tty_queue('\377', ldata); |
1159 | put_tty_queue('\0', ldata); | |
1da177e4 | 1160 | } |
57c94121 | 1161 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1162 | } |
1163 | ||
1164 | /** | |
98629663 JS |
1165 | * n_tty_receive_overrun - handle overrun reporting |
1166 | * @tty: terminal | |
1da177e4 | 1167 | * |
98629663 JS |
1168 | * Data arrived faster than we could process it. While the tty driver has |
1169 | * flagged this the bits that were missed are gone forever. | |
1da177e4 | 1170 | * |
98629663 JS |
1171 | * Called from the receive_buf path so single threaded. Does not need locking |
1172 | * as num_overrun and overrun_time are function private. | |
1da177e4 | 1173 | */ |
4b293492 | 1174 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1175 | { |
53c5ee2c | 1176 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1177 | |
53c5ee2c JS |
1178 | ldata->num_overrun++; |
1179 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1180 | time_after(ldata->overrun_time, jiffies)) { | |
339f36ba | 1181 | tty_warn(tty, "%d input overrun(s)\n", ldata->num_overrun); |
53c5ee2c JS |
1182 | ldata->overrun_time = jiffies; |
1183 | ldata->num_overrun = 0; | |
1da177e4 LT |
1184 | } |
1185 | } | |
1186 | ||
1187 | /** | |
98629663 JS |
1188 | * n_tty_receive_parity_error - error notifier |
1189 | * @tty: terminal device | |
1190 | * @c: character | |
1da177e4 | 1191 | * |
98629663 JS |
1192 | * Process a parity error and queue the right data to indicate the error case |
1193 | * if necessary. | |
6d76bd26 | 1194 | * |
98629663 JS |
1195 | * Locking: n_tty_receive_buf()/producer path: |
1196 | * caller holds non-exclusive %termios_rwsem | |
1da177e4 | 1197 | */ |
4b293492 | 1198 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1199 | { |
57c94121 JS |
1200 | struct n_tty_data *ldata = tty->disc_data; |
1201 | ||
66528f90 PH |
1202 | if (I_INPCK(tty)) { |
1203 | if (I_IGNPAR(tty)) | |
1204 | return; | |
1205 | if (I_PARMRK(tty)) { | |
1206 | put_tty_queue('\377', ldata); | |
1207 | put_tty_queue('\0', ldata); | |
1208 | put_tty_queue(c, ldata); | |
1209 | } else | |
1210 | put_tty_queue('\0', ldata); | |
1211 | } else | |
57c94121 | 1212 | put_tty_queue(c, ldata); |
1da177e4 LT |
1213 | } |
1214 | ||
b0ac50be PH |
1215 | static void |
1216 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1217 | { | |
d2b6f447 | 1218 | isig(signal, tty); |
b0ac50be PH |
1219 | if (I_IXON(tty)) |
1220 | start_tty(tty); | |
1221 | if (L_ECHO(tty)) { | |
1222 | echo_char(c, tty); | |
1223 | commit_echoes(tty); | |
e2613be5 PH |
1224 | } else |
1225 | process_echoes(tty); | |
b0ac50be PH |
1226 | } |
1227 | ||
25e02ba6 IJ |
1228 | static bool n_tty_is_char_flow_ctrl(struct tty_struct *tty, unsigned char c) |
1229 | { | |
1230 | return c == START_CHAR(tty) || c == STOP_CHAR(tty); | |
1231 | } | |
1232 | ||
6bb6fa69 IJ |
1233 | /** |
1234 | * n_tty_receive_char_flow_ctrl - receive flow control chars | |
1235 | * @tty: terminal device | |
1236 | * @c: character | |
1237 | * @lookahead_done: lookahead has processed this character already | |
1238 | * | |
1239 | * Receive and process flow control character actions. | |
1240 | * | |
1241 | * In case lookahead for flow control chars already handled the character in | |
1242 | * advance to the normal receive, the actions are skipped during normal | |
1243 | * receive. | |
1244 | * | |
1245 | * Returns true if @c is consumed as flow-control character, the character | |
1246 | * must not be treated as normal character. | |
1247 | */ | |
1248 | static bool n_tty_receive_char_flow_ctrl(struct tty_struct *tty, unsigned char c, | |
1249 | bool lookahead_done) | |
ec66b8cf | 1250 | { |
25e02ba6 IJ |
1251 | if (!n_tty_is_char_flow_ctrl(tty, c)) |
1252 | return false; | |
1253 | ||
6bb6fa69 IJ |
1254 | if (lookahead_done) |
1255 | return true; | |
1256 | ||
ec66b8cf IJ |
1257 | if (c == START_CHAR(tty)) { |
1258 | start_tty(tty); | |
1259 | process_echoes(tty); | |
1260 | return true; | |
1261 | } | |
ec66b8cf | 1262 | |
25e02ba6 IJ |
1263 | /* STOP_CHAR */ |
1264 | stop_tty(tty); | |
1265 | return true; | |
ec66b8cf IJ |
1266 | } |
1267 | ||
6bb6fa69 IJ |
1268 | static void n_tty_receive_char_special(struct tty_struct *tty, unsigned char c, |
1269 | bool lookahead_done) | |
1da177e4 | 1270 | { |
53c5ee2c | 1271 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1272 | |
6bb6fa69 | 1273 | if (I_IXON(tty) && n_tty_receive_char_flow_ctrl(tty, c, lookahead_done)) |
ec66b8cf | 1274 | return; |
575537b3 | 1275 | |
1da177e4 | 1276 | if (L_ISIG(tty)) { |
b0ac50be PH |
1277 | if (c == INTR_CHAR(tty)) { |
1278 | n_tty_receive_signal_char(tty, SIGINT, c); | |
16765365 | 1279 | return; |
b0ac50be PH |
1280 | } else if (c == QUIT_CHAR(tty)) { |
1281 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
16765365 | 1282 | return; |
b0ac50be PH |
1283 | } else if (c == SUSP_CHAR(tty)) { |
1284 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
16765365 | 1285 | return; |
1da177e4 LT |
1286 | } |
1287 | } | |
575537b3 | 1288 | |
6e94dbc7 | 1289 | if (tty->flow.stopped && !tty->flow.tco_stopped && I_IXON(tty) && I_IXANY(tty)) { |
855df3c0 PH |
1290 | start_tty(tty); |
1291 | process_echoes(tty); | |
1292 | } | |
1293 | ||
575537b3 JP |
1294 | if (c == '\r') { |
1295 | if (I_IGNCR(tty)) | |
16765365 | 1296 | return; |
575537b3 JP |
1297 | if (I_ICRNL(tty)) |
1298 | c = '\n'; | |
1299 | } else if (c == '\n' && I_INLCR(tty)) | |
1300 | c = '\r'; | |
1301 | ||
53c5ee2c | 1302 | if (ldata->icanon) { |
1da177e4 LT |
1303 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1304 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1305 | eraser(c, tty); | |
17bd7907 | 1306 | commit_echoes(tty); |
16765365 | 1307 | return; |
1da177e4 LT |
1308 | } |
1309 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1310 | ldata->lnext = 1; |
1da177e4 | 1311 | if (L_ECHO(tty)) { |
57c94121 | 1312 | finish_erasing(ldata); |
1da177e4 | 1313 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1314 | echo_char_raw('^', ldata); |
1315 | echo_char_raw('\b', ldata); | |
17bd7907 | 1316 | commit_echoes(tty); |
1da177e4 LT |
1317 | } |
1318 | } | |
16765365 | 1319 | return; |
1da177e4 | 1320 | } |
e60d27c4 | 1321 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1322 | size_t tail = ldata->canon_head; |
1da177e4 | 1323 | |
57c94121 | 1324 | finish_erasing(ldata); |
1da177e4 | 1325 | echo_char(c, tty); |
57c94121 | 1326 | echo_char_raw('\n', ldata); |
3d63b7e4 | 1327 | while (MASK(tail) != MASK(ldata->read_head)) { |
bc5a5e3f PH |
1328 | echo_char(read_buf(ldata, tail), tty); |
1329 | tail++; | |
1da177e4 | 1330 | } |
17bd7907 | 1331 | commit_echoes(tty); |
16765365 | 1332 | return; |
1da177e4 LT |
1333 | } |
1334 | if (c == '\n') { | |
acc71bba | 1335 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1336 | echo_char_raw('\n', ldata); |
17bd7907 | 1337 | commit_echoes(tty); |
1da177e4 LT |
1338 | } |
1339 | goto handle_newline; | |
1340 | } | |
1341 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1342 | c = __DISABLED_CHAR; |
1343 | goto handle_newline; | |
1344 | } | |
1345 | if ((c == EOL_CHAR(tty)) || | |
1346 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1347 | /* | |
1348 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1349 | */ | |
1350 | if (L_ECHO(tty)) { | |
1da177e4 | 1351 | /* Record the column of first canon char. */ |
ba2e68ac | 1352 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1353 | echo_set_canon_col(ldata); |
1da177e4 | 1354 | echo_char(c, tty); |
17bd7907 | 1355 | commit_echoes(tty); |
1da177e4 LT |
1356 | } |
1357 | /* | |
1358 | * XXX does PARMRK doubling happen for | |
1359 | * EOL_CHAR and EOL2_CHAR? | |
1360 | */ | |
001ba923 | 1361 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
57c94121 | 1362 | put_tty_queue(c, ldata); |
1da177e4 | 1363 | |
4edf1827 | 1364 | handle_newline: |
bc5a5e3f | 1365 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1366 | put_tty_queue(c, ldata); |
70aca71f | 1367 | smp_store_release(&ldata->canon_head, ldata->read_head); |
1da177e4 | 1368 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
c816b2e6 | 1369 | wake_up_interruptible_poll(&tty->read_wait, EPOLLIN | EPOLLRDNORM); |
16765365 | 1370 | return; |
1da177e4 LT |
1371 | } |
1372 | } | |
4edf1827 | 1373 | |
acc71bba | 1374 | if (L_ECHO(tty)) { |
57c94121 | 1375 | finish_erasing(ldata); |
1da177e4 | 1376 | if (c == '\n') |
57c94121 | 1377 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1378 | else { |
1379 | /* Record the column of first canon char. */ | |
ba2e68ac | 1380 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1381 | echo_set_canon_col(ldata); |
1da177e4 LT |
1382 | echo_char(c, tty); |
1383 | } | |
17bd7907 | 1384 | commit_echoes(tty); |
1da177e4 LT |
1385 | } |
1386 | ||
001ba923 PH |
1387 | /* PARMRK doubling check */ |
1388 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
57c94121 | 1389 | put_tty_queue(c, ldata); |
1da177e4 | 1390 | |
57c94121 | 1391 | put_tty_queue(c, ldata); |
4edf1827 | 1392 | } |
1da177e4 | 1393 | |
c66453ce | 1394 | /** |
98629663 JS |
1395 | * n_tty_receive_char - perform processing |
1396 | * @tty: terminal device | |
1397 | * @c: character | |
c66453ce | 1398 | * |
98629663 JS |
1399 | * Process an individual character of input received from the driver. This is |
1400 | * serialized with respect to itself by the rules for the driver above. | |
c66453ce | 1401 | * |
98629663 JS |
1402 | * Locking: n_tty_receive_buf()/producer path: |
1403 | * caller holds non-exclusive %termios_rwsem | |
1404 | * publishes canon_head if canonical mode is active | |
c66453ce | 1405 | */ |
95aafe32 | 1406 | static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
4b1f79c2 PH |
1407 | { |
1408 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1409 | |
6e94dbc7 | 1410 | if (tty->flow.stopped && !tty->flow.tco_stopped && I_IXON(tty) && I_IXANY(tty)) { |
e60d27c4 PH |
1411 | start_tty(tty); |
1412 | process_echoes(tty); | |
1413 | } | |
1414 | if (L_ECHO(tty)) { | |
1415 | finish_erasing(ldata); | |
1416 | /* Record the column of first canon char. */ | |
1417 | if (ldata->canon_head == ldata->read_head) | |
1418 | echo_set_canon_col(ldata); | |
1419 | echo_char(c, tty); | |
1420 | commit_echoes(tty); | |
4b1f79c2 | 1421 | } |
001ba923 | 1422 | /* PARMRK doubling check */ |
95aafe32 | 1423 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
e60d27c4 PH |
1424 | put_tty_queue(c, ldata); |
1425 | put_tty_queue(c, ldata); | |
1426 | } | |
4b1f79c2 | 1427 | |
6bb6fa69 IJ |
1428 | static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c, |
1429 | bool lookahead_done) | |
ad0cc7ba PH |
1430 | { |
1431 | if (I_ISTRIP(tty)) | |
1432 | c &= 0x7f; | |
1433 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1434 | c = tolower(c); | |
1435 | ||
1436 | if (I_IXON(tty)) { | |
65534736 IJ |
1437 | if (!n_tty_receive_char_flow_ctrl(tty, c, lookahead_done) && |
1438 | tty->flow.stopped && !tty->flow.tco_stopped && I_IXANY(tty) && | |
1439 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1440 | c != SUSP_CHAR(tty)) { | |
ad0cc7ba PH |
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 | { | |
d2f8d7ab PH |
1450 | switch (flag) { |
1451 | case TTY_BREAK: | |
1452 | n_tty_receive_break(tty); | |
1453 | break; | |
1454 | case TTY_PARITY: | |
1455 | case TTY_FRAME: | |
1456 | n_tty_receive_parity_error(tty, c); | |
1457 | break; | |
1458 | case TTY_OVERRUN: | |
1459 | n_tty_receive_overrun(tty); | |
1460 | break; | |
1461 | default: | |
339f36ba | 1462 | tty_err(tty, "unknown flag %d\n", flag); |
d2f8d7ab PH |
1463 | break; |
1464 | } | |
1465 | } | |
1466 | ||
e60d27c4 PH |
1467 | static void |
1468 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1469 | { | |
1470 | struct n_tty_data *ldata = tty->disc_data; | |
1471 | ||
1472 | ldata->lnext = 0; | |
1473 | if (likely(flag == TTY_NORMAL)) { | |
1474 | if (I_ISTRIP(tty)) | |
1475 | c &= 0x7f; | |
1476 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1477 | c = tolower(c); | |
95aafe32 | 1478 | n_tty_receive_char(tty, c); |
e60d27c4 PH |
1479 | } else |
1480 | n_tty_receive_char_flagged(tty, c, flag); | |
1481 | } | |
1482 | ||
6bb6fa69 IJ |
1483 | /* Caller must ensure count > 0 */ |
1484 | static void n_tty_lookahead_flow_ctrl(struct tty_struct *tty, const unsigned char *cp, | |
1485 | const unsigned char *fp, unsigned int count) | |
1486 | { | |
1487 | struct n_tty_data *ldata = tty->disc_data; | |
1488 | unsigned char flag = TTY_NORMAL; | |
1489 | ||
1490 | ldata->lookahead_count += count; | |
1491 | ||
1492 | if (!I_IXON(tty)) | |
1493 | return; | |
1494 | ||
1495 | while (count--) { | |
1496 | if (fp) | |
1497 | flag = *fp++; | |
1498 | if (likely(flag == TTY_NORMAL)) | |
1499 | n_tty_receive_char_flow_ctrl(tty, *cp, false); | |
1500 | cp++; | |
1501 | } | |
1502 | } | |
1503 | ||
4a23a4df PH |
1504 | static void |
1505 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
0f3dcf3b | 1506 | const char *fp, int count) |
4a23a4df PH |
1507 | { |
1508 | struct n_tty_data *ldata = tty->disc_data; | |
1509 | size_t n, head; | |
1510 | ||
1511 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1512 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1513 | memcpy(read_buf_addr(ldata, head), cp, n); |
1514 | ldata->read_head += n; | |
1515 | cp += n; | |
1516 | count -= n; | |
1517 | ||
1518 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1519 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1520 | memcpy(read_buf_addr(ldata, head), cp, n); |
1521 | ldata->read_head += n; | |
1522 | } | |
1523 | ||
554117bd PH |
1524 | static void |
1525 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
0f3dcf3b | 1526 | const char *fp, int count) |
554117bd PH |
1527 | { |
1528 | struct n_tty_data *ldata = tty->disc_data; | |
1529 | char flag = TTY_NORMAL; | |
1530 | ||
1531 | while (count--) { | |
1532 | if (fp) | |
1533 | flag = *fp++; | |
1534 | if (likely(flag == TTY_NORMAL)) | |
1535 | put_tty_queue(*cp++, ldata); | |
1536 | else | |
1537 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1538 | } | |
1539 | } | |
1540 | ||
ad0cc7ba PH |
1541 | static void |
1542 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
6bb6fa69 | 1543 | const char *fp, int count, bool lookahead_done) |
ad0cc7ba PH |
1544 | { |
1545 | char flag = TTY_NORMAL; | |
1546 | ||
1547 | while (count--) { | |
1548 | if (fp) | |
1549 | flag = *fp++; | |
1550 | if (likely(flag == TTY_NORMAL)) | |
6bb6fa69 | 1551 | n_tty_receive_char_closing(tty, *cp++, lookahead_done); |
ad0cc7ba PH |
1552 | } |
1553 | } | |
1554 | ||
1ed2dfed | 1555 | static void n_tty_receive_buf_standard(struct tty_struct *tty, |
6bb6fa69 | 1556 | const unsigned char *cp, const char *fp, int count, bool lookahead_done) |
6baad008 PH |
1557 | { |
1558 | struct n_tty_data *ldata = tty->disc_data; | |
1559 | char flag = TTY_NORMAL; | |
1560 | ||
1561 | while (count--) { | |
3a7d530a JS |
1562 | unsigned char c = *cp++; |
1563 | ||
6baad008 PH |
1564 | if (fp) |
1565 | flag = *fp++; | |
67a620d5 JS |
1566 | |
1567 | if (ldata->lnext) { | |
3a7d530a | 1568 | n_tty_receive_char_lnext(tty, c, flag); |
67a620d5 JS |
1569 | continue; |
1570 | } | |
1571 | ||
e8f2a139 | 1572 | if (unlikely(flag != TTY_NORMAL)) { |
3a7d530a | 1573 | n_tty_receive_char_flagged(tty, c, flag); |
e8f2a139 JS |
1574 | continue; |
1575 | } | |
1576 | ||
1577 | if (I_ISTRIP(tty)) | |
1578 | c &= 0x7f; | |
1579 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1580 | c = tolower(c); | |
1581 | if (L_EXTPROC(tty)) { | |
1582 | put_tty_queue(c, ldata); | |
1583 | continue; | |
1584 | } | |
1585 | ||
1586 | if (test_bit(c, ldata->char_map)) | |
6bb6fa69 | 1587 | n_tty_receive_char_special(tty, c, lookahead_done); |
e8f2a139 JS |
1588 | else |
1589 | n_tty_receive_char(tty, c); | |
6baad008 PH |
1590 | } |
1591 | } | |
1592 | ||
24a89d1c | 1593 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
0f3dcf3b | 1594 | const char *fp, int count) |
1da177e4 | 1595 | { |
53c5ee2c | 1596 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1597 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
6bb6fa69 | 1598 | size_t la_count = min_t(size_t, ldata->lookahead_count, count); |
1da177e4 | 1599 | |
4a23a4df PH |
1600 | if (ldata->real_raw) |
1601 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1602 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1603 | n_tty_receive_buf_raw(tty, cp, fp, count); |
6bb6fa69 IJ |
1604 | else if (tty->closing && !L_EXTPROC(tty)) { |
1605 | if (la_count > 0) | |
1606 | n_tty_receive_buf_closing(tty, cp, fp, la_count, true); | |
1607 | if (count > la_count) | |
1608 | n_tty_receive_buf_closing(tty, cp, fp, count - la_count, false); | |
1609 | } else { | |
1610 | if (la_count > 0) | |
1611 | n_tty_receive_buf_standard(tty, cp, fp, la_count, true); | |
1612 | if (count > la_count) | |
1613 | n_tty_receive_buf_standard(tty, cp, fp, count - la_count, false); | |
cbfd0340 PH |
1614 | |
1615 | flush_echoes(tty); | |
f34d7a5b AC |
1616 | if (tty->ops->flush_chars) |
1617 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1618 | } |
1619 | ||
6bb6fa69 IJ |
1620 | ldata->lookahead_count -= la_count; |
1621 | ||
70aca71f PH |
1622 | if (ldata->icanon && !L_EXTPROC(tty)) |
1623 | return; | |
1624 | ||
1625 | /* publish read_head to consumer */ | |
1626 | smp_store_release(&ldata->commit_head, ldata->read_head); | |
1627 | ||
33d71363 | 1628 | if (read_cnt(ldata)) { |
1da177e4 | 1629 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
c816b2e6 | 1630 | wake_up_interruptible_poll(&tty->read_wait, EPOLLIN | EPOLLRDNORM); |
1da177e4 | 1631 | } |
1da177e4 LT |
1632 | } |
1633 | ||
fb5ef9e7 | 1634 | /** |
98629663 JS |
1635 | * n_tty_receive_buf_common - process input |
1636 | * @tty: device to receive input | |
1637 | * @cp: input chars | |
1638 | * @fp: flags for each char (if %NULL, all chars are %TTY_NORMAL) | |
1639 | * @count: number of input chars in @cp | |
1640 | * @flow: enable flow control | |
1641 | * | |
1642 | * Called by the terminal driver when a block of characters has been received. | |
1643 | * This function must be called from soft contexts not from interrupt context. | |
1644 | * The driver is responsible for making calls one at a time and in order (or | |
1645 | * using flush_to_ldisc()). | |
1646 | * | |
1647 | * Returns: the # of input chars from @cp which were processed. | |
1648 | * | |
1649 | * In canonical mode, the maximum line length is 4096 chars (including the line | |
1650 | * termination char); lines longer than 4096 chars are truncated. After 4095 | |
1651 | * chars, input data is still processed but not stored. Overflow processing | |
1652 | * ensures the tty can always receive more input until at least one line can be | |
1653 | * read. | |
1654 | * | |
1655 | * In non-canonical mode, the read buffer will only accept 4095 chars; this | |
1656 | * provides the necessary space for a newline char if the input mode is | |
1657 | * switched to canonical. | |
1658 | * | |
1659 | * Note it is possible for the read buffer to _contain_ 4096 chars in | |
1660 | * non-canonical mode: the read buffer could already contain the maximum canon | |
1661 | * line of 4096 chars when the mode is switched to non-canonical. | |
1662 | * | |
1663 | * Locking: n_tty_receive_buf()/producer path: | |
1664 | * claims non-exclusive %termios_rwsem | |
1665 | * publishes commit_head or canon_head | |
fb5ef9e7 | 1666 | */ |
5c32d123 PH |
1667 | static int |
1668 | n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, | |
0f3dcf3b | 1669 | const char *fp, int count, int flow) |
24a89d1c PH |
1670 | { |
1671 | struct n_tty_data *ldata = tty->disc_data; | |
fb5ef9e7 | 1672 | int room, n, rcvd = 0, overflow; |
24a89d1c | 1673 | |
9356b535 PH |
1674 | down_read(&tty->termios_rwsem); |
1675 | ||
c96cf923 | 1676 | do { |
70aca71f | 1677 | /* |
06c49f9f PH |
1678 | * When PARMRK is set, each input char may take up to 3 chars |
1679 | * in the read buf; reduce the buffer space avail by 3x | |
70aca71f PH |
1680 | * |
1681 | * If we are doing input canonicalization, and there are no | |
1682 | * pending newlines, let characters through without limit, so | |
1683 | * that erase characters will be handled. Other excess | |
1684 | * characters will be beeped. | |
1685 | * | |
1686 | * paired with store in *_copy_from_read_buf() -- guarantees | |
1687 | * the consumer has loaded the data in read_buf up to the new | |
1688 | * read_tail (so this producer will not overwrite unread data) | |
1689 | */ | |
1690 | size_t tail = smp_load_acquire(&ldata->read_tail); | |
70aca71f | 1691 | |
fb5ef9e7 | 1692 | room = N_TTY_BUF_SIZE - (ldata->read_head - tail); |
70aca71f | 1693 | if (I_PARMRK(tty)) |
fb5ef9e7 PH |
1694 | room = (room + 2) / 3; |
1695 | room--; | |
1696 | if (room <= 0) { | |
1697 | overflow = ldata->icanon && ldata->canon_head == tail; | |
1698 | if (overflow && room < 0) | |
1699 | ldata->read_head--; | |
1700 | room = overflow; | |
1701 | ldata->no_room = flow && !room; | |
1702 | } else | |
1703 | overflow = 0; | |
70aca71f | 1704 | |
19e2ad6a | 1705 | n = min(count, room); |
fb5ef9e7 | 1706 | if (!n) |
19e2ad6a | 1707 | break; |
fb5ef9e7 PH |
1708 | |
1709 | /* ignore parity errors if handling overflow */ | |
1710 | if (!overflow || !fp || *fp != TTY_PARITY) | |
1711 | __receive_buf(tty, cp, fp, n); | |
1712 | ||
19e2ad6a PH |
1713 | cp += n; |
1714 | if (fp) | |
1715 | fp += n; | |
1716 | count -= n; | |
1717 | rcvd += n; | |
c96cf923 | 1718 | } while (!test_bit(TTY_LDISC_CHANGING, &tty->flags)); |
24a89d1c | 1719 | |
19e2ad6a | 1720 | tty->receive_room = room; |
fb5ef9e7 PH |
1721 | |
1722 | /* Unthrottle if handling overflow on pty */ | |
1723 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { | |
1724 | if (overflow) { | |
1725 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1726 | tty_unthrottle_safe(tty); | |
1727 | __tty_set_flow_change(tty, 0); | |
1728 | } | |
1729 | } else | |
1730 | n_tty_check_throttle(tty); | |
1731 | ||
9356b535 PH |
1732 | up_read(&tty->termios_rwsem); |
1733 | ||
19e2ad6a | 1734 | return rcvd; |
24a89d1c PH |
1735 | } |
1736 | ||
5c32d123 | 1737 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
0f3dcf3b | 1738 | const char *fp, int count) |
5c32d123 PH |
1739 | { |
1740 | n_tty_receive_buf_common(tty, cp, fp, count, 0); | |
1741 | } | |
1742 | ||
1743 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
0f3dcf3b | 1744 | const char *fp, int count) |
5c32d123 PH |
1745 | { |
1746 | return n_tty_receive_buf_common(tty, cp, fp, count, 1); | |
1747 | } | |
1748 | ||
1da177e4 | 1749 | /** |
98629663 JS |
1750 | * n_tty_set_termios - termios data changed |
1751 | * @tty: terminal | |
1752 | * @old: previous data | |
1da177e4 | 1753 | * |
98629663 JS |
1754 | * Called by the tty layer when the user changes termios flags so that the line |
1755 | * discipline can plan ahead. This function cannot sleep and is protected from | |
1756 | * re-entry by the tty layer. The user is guaranteed that this function will | |
1757 | * not be re-entered or in progress when the ldisc is closed. | |
17b82060 | 1758 | * |
98629663 | 1759 | * Locking: Caller holds @tty->termios_rwsem |
1da177e4 | 1760 | */ |
8b7d2d95 | 1761 | static void n_tty_set_termios(struct tty_struct *tty, const struct ktermios *old) |
1da177e4 | 1762 | { |
53c5ee2c | 1763 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1764 | |
966031f3 | 1765 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & (ICANON | EXTPROC)) { |
3fe780b3 | 1766 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1767 | ldata->line_start = ldata->read_tail; |
1768 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1769 | ldata->canon_head = ldata->read_tail; | |
1770 | ldata->push = 0; | |
1771 | } else { | |
1772 | set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), | |
1773 | ldata->read_flags); | |
1774 | ldata->canon_head = ldata->read_head; | |
1775 | ldata->push = 1; | |
1776 | } | |
70aca71f | 1777 | ldata->commit_head = ldata->read_head; |
53c5ee2c | 1778 | ldata->erasing = 0; |
6f9b028a | 1779 | ldata->lnext = 0; |
47afa7a5 AC |
1780 | } |
1781 | ||
53c5ee2c | 1782 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1783 | |
1da177e4 LT |
1784 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1785 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1786 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1787 | I_PARMRK(tty)) { | |
1bb9d562 | 1788 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1789 | |
1790 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1791 | set_bit('\r', ldata->char_map); |
1da177e4 | 1792 | if (I_INLCR(tty)) |
1bb9d562 | 1793 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1794 | |
1795 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1796 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1797 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1798 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1799 | set_bit('\n', ldata->char_map); | |
1800 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1801 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1802 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1803 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1804 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1805 | if (L_ECHO(tty)) |
1806 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1807 | ldata->char_map); |
1da177e4 LT |
1808 | } |
1809 | } | |
1810 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1811 | set_bit(START_CHAR(tty), ldata->char_map); |
1812 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1813 | } |
1814 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1815 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1816 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1817 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1818 | } |
1bb9d562 | 1819 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1820 | ldata->raw = 0; |
1821 | ldata->real_raw = 0; | |
1da177e4 | 1822 | } else { |
53c5ee2c | 1823 | ldata->raw = 1; |
1da177e4 LT |
1824 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1825 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1826 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1827 | ldata->real_raw = 1; |
1da177e4 | 1828 | else |
53c5ee2c | 1829 | ldata->real_raw = 0; |
1da177e4 | 1830 | } |
dab73b4e WY |
1831 | /* |
1832 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1833 | * been stopped by STOP_CHAR(tty) before it. | |
1834 | */ | |
6e94dbc7 | 1835 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow.tco_stopped) { |
dab73b4e | 1836 | start_tty(tty); |
e2613be5 PH |
1837 | process_echoes(tty); |
1838 | } | |
dab73b4e | 1839 | |
f34d7a5b | 1840 | /* The termios change make the tty ready for I/O */ |
e81107d4 KT |
1841 | wake_up_interruptible(&tty->write_wait); |
1842 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1843 | } |
1844 | ||
1845 | /** | |
98629663 JS |
1846 | * n_tty_close - close the ldisc for this tty |
1847 | * @tty: device | |
1da177e4 | 1848 | * |
98629663 JS |
1849 | * Called from the terminal layer when this line discipline is being shut down, |
1850 | * either because of a close or becsuse of a discipline change. The function | |
1851 | * will not be called while other ldisc methods are in progress. | |
1da177e4 | 1852 | */ |
1da177e4 LT |
1853 | static void n_tty_close(struct tty_struct *tty) |
1854 | { | |
70ece7a7 JS |
1855 | struct n_tty_data *ldata = tty->disc_data; |
1856 | ||
79901317 PH |
1857 | if (tty->link) |
1858 | n_tty_packet_mode_flush(tty); | |
1859 | ||
c9cd57bf | 1860 | down_write(&tty->termios_rwsem); |
20bafb3d | 1861 | vfree(ldata); |
70ece7a7 | 1862 | tty->disc_data = NULL; |
c9cd57bf | 1863 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
1864 | } |
1865 | ||
1866 | /** | |
98629663 JS |
1867 | * n_tty_open - open an ldisc |
1868 | * @tty: terminal to open | |
1da177e4 | 1869 | * |
98629663 JS |
1870 | * Called when this line discipline is being attached to the terminal device. |
1871 | * Can sleep. Called serialized so that no other events will occur in parallel. | |
1872 | * No further open will occur until a close. | |
1da177e4 | 1873 | */ |
1da177e4 LT |
1874 | static int n_tty_open(struct tty_struct *tty) |
1875 | { | |
70ece7a7 JS |
1876 | struct n_tty_data *ldata; |
1877 | ||
20bafb3d | 1878 | /* Currently a malloc failure here can panic */ |
ebec3f8f | 1879 | ldata = vzalloc(sizeof(*ldata)); |
70ece7a7 | 1880 | if (!ldata) |
ebec3f8f | 1881 | return -ENOMEM; |
70ece7a7 | 1882 | |
53c5ee2c | 1883 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1884 | mutex_init(&ldata->atomic_read_lock); |
1885 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1886 | |
70ece7a7 | 1887 | tty->disc_data = ldata; |
1da177e4 | 1888 | tty->closing = 0; |
b66f4fa5 PH |
1889 | /* indicate buffer work may resume */ |
1890 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1891 | n_tty_set_termios(tty, NULL); | |
1892 | tty_unthrottle(tty); | |
1da177e4 LT |
1893 | return 0; |
1894 | } | |
1895 | ||
eafbe67f | 1896 | static inline int input_available_p(struct tty_struct *tty, int poll) |
1da177e4 | 1897 | { |
53c5ee2c | 1898 | struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1899 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1900 | |
25e8d0ed PH |
1901 | if (ldata->icanon && !L_EXTPROC(tty)) |
1902 | return ldata->canon_head != ldata->read_tail; | |
1903 | else | |
70aca71f | 1904 | return ldata->commit_head - ldata->read_tail >= amt; |
1da177e4 LT |
1905 | } |
1906 | ||
1907 | /** | |
98629663 JS |
1908 | * copy_from_read_buf - copy read data directly |
1909 | * @tty: terminal device | |
1910 | * @kbp: data | |
1911 | * @nr: size of data | |
1da177e4 | 1912 | * |
98629663 JS |
1913 | * Helper function to speed up n_tty_read(). It is only called when %ICANON is |
1914 | * off; it copies characters straight from the tty queue. | |
1da177e4 | 1915 | * |
98629663 JS |
1916 | * Returns: true if it successfully copied data, but there is still more data |
1917 | * to be had. | |
15ea8ae8 | 1918 | * |
98629663 JS |
1919 | * Locking: |
1920 | * * called under the @ldata->atomic_read_lock sem | |
1921 | * * n_tty_read()/consumer path: | |
1922 | * caller holds non-exclusive %termios_rwsem; | |
6d76bd26 | 1923 | * read_tail published |
1da177e4 | 1924 | */ |
15ea8ae8 | 1925 | static bool copy_from_read_buf(struct tty_struct *tty, |
3b830a9c | 1926 | unsigned char **kbp, |
1da177e4 LT |
1927 | size_t *nr) |
1928 | ||
1929 | { | |
53c5ee2c | 1930 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1931 | size_t n; |
3fa10cc8 | 1932 | bool is_eof; |
70aca71f | 1933 | size_t head = smp_load_acquire(&ldata->commit_head); |
bc5a5e3f | 1934 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 | 1935 | |
70aca71f | 1936 | n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail); |
1da177e4 | 1937 | n = min(*nr, n); |
1da177e4 | 1938 | if (n) { |
b97b3d9f | 1939 | unsigned char *from = read_buf_addr(ldata, tail); |
3b830a9c | 1940 | memcpy(*kbp, from, n); |
e661cf70 | 1941 | is_eof = n == 1 && *from == EOF_CHAR(tty); |
309426ae | 1942 | tty_audit_add_data(tty, from, n); |
b97b3d9f | 1943 | zero_buffer(tty, from, n); |
70aca71f | 1944 | smp_store_release(&ldata->read_tail, ldata->read_tail + n); |
26df6d13 | 1945 | /* Turn single EOF into zero-length read */ |
70aca71f PH |
1946 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && |
1947 | (head == ldata->read_tail)) | |
15ea8ae8 | 1948 | return false; |
3b830a9c | 1949 | *kbp += n; |
1da177e4 | 1950 | *nr -= n; |
15ea8ae8 LT |
1951 | |
1952 | /* If we have more to copy, let the caller know */ | |
1953 | return head != ldata->read_tail; | |
1da177e4 | 1954 | } |
15ea8ae8 | 1955 | return false; |
1da177e4 LT |
1956 | } |
1957 | ||
88bb0de3 | 1958 | /** |
98629663 JS |
1959 | * canon_copy_from_read_buf - copy read data in canonical mode |
1960 | * @tty: terminal device | |
1961 | * @kbp: data | |
1962 | * @nr: size of data | |
1963 | * | |
1964 | * Helper function for n_tty_read(). It is only called when %ICANON is on; it | |
1965 | * copies one line of input up to and including the line-delimiting character | |
1966 | * into the result buffer. | |
1967 | * | |
1968 | * Note: When termios is changed from non-canonical to canonical mode and the | |
1969 | * read buffer contains data, n_tty_set_termios() simulates an EOF push (as if | |
1970 | * C-d were input) _without_ the %DISABLED_CHAR in the buffer. This causes data | |
1971 | * already processed as input to be immediately available as input although a | |
1972 | * newline has not been received. | |
1973 | * | |
1974 | * Locking: | |
1975 | * * called under the %atomic_read_lock mutex | |
1976 | * * n_tty_read()/consumer path: | |
1977 | * caller holds non-exclusive %termios_rwsem; | |
1978 | * read_tail published | |
88bb0de3 | 1979 | */ |
d7fe75cb | 1980 | static bool canon_copy_from_read_buf(struct tty_struct *tty, |
64a69892 LT |
1981 | unsigned char **kbp, |
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 | 1986 | size_t eol; |
d7fe75cb | 1987 | size_t tail, canon_head; |
3b830a9c | 1988 | int found = 0; |
88bb0de3 PH |
1989 | |
1990 | /* N.B. avoid overrun if nr == 0 */ | |
ac8f3bf8 | 1991 | if (!*nr) |
d7fe75cb | 1992 | return false; |
88bb0de3 | 1993 | |
d7fe75cb | 1994 | canon_head = smp_load_acquire(&ldata->canon_head); |
35930307 | 1995 | n = min(*nr, canon_head - ldata->read_tail); |
ac8f3bf8 | 1996 | |
bc5a5e3f | 1997 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
1998 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
1999 | ||
bc5a5e3f | 2000 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2001 | __func__, *nr, tail, n, size); |
2002 | ||
2003 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2004 | more = n - (size - tail); | |
2005 | if (eol == N_TTY_BUF_SIZE && more) { | |
2006 | /* scan wrapped without finding set bit */ | |
b5c7e7ec | 2007 | eol = find_first_bit(ldata->read_flags, more); |
b985e9e3 PH |
2008 | found = eol != more; |
2009 | } else | |
2010 | found = eol != size; | |
32f13521 | 2011 | |
c77569d2 | 2012 | n = eol - tail; |
da555db6 MT |
2013 | if (n > N_TTY_BUF_SIZE) |
2014 | n += N_TTY_BUF_SIZE; | |
ac8f3bf8 | 2015 | c = n + found; |
32f13521 | 2016 | |
35930307 | 2017 | if (!found || read_buf(ldata, eol) != __DISABLED_CHAR) |
ac8f3bf8 | 2018 | n = c; |
32f13521 | 2019 | |
679e7c29 PH |
2020 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu tail:%zu more:%zu\n", |
2021 | __func__, eol, found, n, c, tail, more); | |
32f13521 | 2022 | |
3b830a9c LT |
2023 | tty_copy(tty, *kbp, tail, n); |
2024 | *kbp += n; | |
32f13521 PH |
2025 | *nr -= n; |
2026 | ||
a73d3d69 | 2027 | if (found) |
6d76bd26 | 2028 | clear_bit(eol, ldata->read_flags); |
70aca71f | 2029 | smp_store_release(&ldata->read_tail, ldata->read_tail + c); |
88bb0de3 | 2030 | |
40d5e090 | 2031 | if (found) { |
4d0ed182 PH |
2032 | if (!ldata->push) |
2033 | ldata->line_start = ldata->read_tail; | |
2034 | else | |
2035 | ldata->push = 0; | |
b50819f4 | 2036 | tty_audit_push(); |
d7fe75cb | 2037 | return false; |
40d5e090 | 2038 | } |
d7fe75cb LT |
2039 | |
2040 | /* No EOL found - do a continuation retry if there is more data */ | |
2041 | return ldata->read_tail != canon_head; | |
88bb0de3 PH |
2042 | } |
2043 | ||
65a8b287 DG |
2044 | /* |
2045 | * If we finished a read at the exact location of an | |
2046 | * EOF (special EOL character that's a __DISABLED_CHAR) | |
2047 | * in the stream, silently eat the EOF. | |
2048 | */ | |
2049 | static void canon_skip_eof(struct tty_struct *tty) | |
2050 | { | |
2051 | struct n_tty_data *ldata = tty->disc_data; | |
2052 | size_t tail, canon_head; | |
2053 | ||
2054 | canon_head = smp_load_acquire(&ldata->canon_head); | |
2055 | tail = ldata->read_tail; | |
2056 | ||
2057 | // No data? | |
2058 | if (tail == canon_head) | |
2059 | return; | |
2060 | ||
2061 | // See if the tail position is EOF in the circular buffer | |
2062 | tail &= (N_TTY_BUF_SIZE - 1); | |
2063 | if (!test_bit(tail, ldata->read_flags)) | |
2064 | return; | |
2065 | if (read_buf(ldata, tail) != __DISABLED_CHAR) | |
2066 | return; | |
2067 | ||
2068 | // Clear the EOL bit, skip the EOF char. | |
2069 | clear_bit(tail, ldata->read_flags); | |
2070 | smp_store_release(&ldata->read_tail, ldata->read_tail + 1); | |
2071 | } | |
2072 | ||
1da177e4 | 2073 | /** |
98629663 JS |
2074 | * job_control - check job control |
2075 | * @tty: tty | |
2076 | * @file: file handle | |
2077 | * | |
2078 | * Perform job control management checks on this @file/@tty descriptor and if | |
2079 | * appropriate send any needed signals and return a negative error code if | |
2080 | * action should be taken. | |
2081 | * | |
2082 | * Locking: | |
2083 | * * redirected write test is safe | |
2084 | * * current->signal->tty check is safe | |
2085 | * * ctrl.lock to safely reference @tty->ctrl.pgrp | |
1da177e4 | 2086 | */ |
1da177e4 LT |
2087 | static int job_control(struct tty_struct *tty, struct file *file) |
2088 | { | |
2089 | /* Job control check -- must be done at start and after | |
2090 | every sleep (POSIX.1 7.1.1.4). */ | |
2091 | /* NOTE: not yet done after every sleep pending a thorough | |
2092 | check of the logic of this change. -- jlc */ | |
2093 | /* don't stop on /dev/console */ | |
9f12e37c | 2094 | if (file->f_op->write_iter == redirected_tty_write) |
01a5e440 PH |
2095 | return 0; |
2096 | ||
2812d9e9 | 2097 | return __tty_check_change(tty, SIGTTIN); |
1da177e4 | 2098 | } |
4edf1827 | 2099 | |
1da177e4 LT |
2100 | |
2101 | /** | |
98629663 JS |
2102 | * n_tty_read - read function for tty |
2103 | * @tty: tty device | |
2104 | * @file: file object | |
2105 | * @kbuf: kernelspace buffer pointer | |
2106 | * @nr: size of I/O | |
2107 | * @cookie: if non-%NULL, this is a continuation read | |
2108 | * @offset: where to continue reading from (unused in n_tty) | |
2109 | * | |
2110 | * Perform reads for the line discipline. We are guaranteed that the line | |
2111 | * discipline will not be closed under us but we may get multiple parallel | |
2112 | * readers and must handle this ourselves. We may also get a hangup. Always | |
2113 | * called in user context, may sleep. | |
2114 | * | |
2115 | * This code must be sure never to sleep through a hangup. | |
2116 | * | |
2117 | * Locking: n_tty_read()/consumer path: | |
2118 | * claims non-exclusive termios_rwsem; | |
2119 | * publishes read_tail | |
1da177e4 | 2120 | */ |
11a96d18 | 2121 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
3b830a9c LT |
2122 | unsigned char *kbuf, size_t nr, |
2123 | void **cookie, unsigned long offset) | |
1da177e4 | 2124 | { |
53c5ee2c | 2125 | struct n_tty_data *ldata = tty->disc_data; |
3b830a9c | 2126 | unsigned char *kb = kbuf; |
97d9e28d | 2127 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
0f40fbbc | 2128 | int c; |
1da177e4 LT |
2129 | int minimum, time; |
2130 | ssize_t retval = 0; | |
1da177e4 | 2131 | long timeout; |
64d608db | 2132 | bool packet; |
947d66b6 | 2133 | size_t old_tail; |
1da177e4 | 2134 | |
15ea8ae8 LT |
2135 | /* |
2136 | * Is this a continuation of a read started earler? | |
2137 | * | |
2138 | * If so, we still hold the atomic_read_lock and the | |
2139 | * termios_rwsem, and can just continue to copy data. | |
2140 | */ | |
2141 | if (*cookie) { | |
d7fe75cb | 2142 | if (ldata->icanon && !L_EXTPROC(tty)) { |
65a8b287 DG |
2143 | /* |
2144 | * If we have filled the user buffer, see | |
2145 | * if we should skip an EOF character before | |
2146 | * releasing the lock and returning done. | |
2147 | */ | |
2148 | if (!nr) | |
2149 | canon_skip_eof(tty); | |
2150 | else if (canon_copy_from_read_buf(tty, &kb, &nr)) | |
d7fe75cb LT |
2151 | return kb - kbuf; |
2152 | } else { | |
2153 | if (copy_from_read_buf(tty, &kb, &nr)) | |
2154 | return kb - kbuf; | |
2155 | } | |
15ea8ae8 LT |
2156 | |
2157 | /* No more data - release locks and stop retries */ | |
2158 | n_tty_kick_worker(tty); | |
2159 | n_tty_check_unthrottle(tty); | |
2160 | up_read(&tty->termios_rwsem); | |
2161 | mutex_unlock(&ldata->atomic_read_lock); | |
2162 | *cookie = NULL; | |
2163 | return kb - kbuf; | |
2164 | } | |
2165 | ||
1da177e4 | 2166 | c = job_control(tty, file); |
4edf1827 | 2167 | if (c < 0) |
1da177e4 | 2168 | return c; |
4edf1827 | 2169 | |
aefceaf4 PH |
2170 | /* |
2171 | * Internal serialization of reads. | |
2172 | */ | |
2173 | if (file->f_flags & O_NONBLOCK) { | |
2174 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2175 | return -EAGAIN; | |
2176 | } else { | |
2177 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2178 | return -ERESTARTSYS; | |
2179 | } | |
2180 | ||
9356b535 PH |
2181 | down_read(&tty->termios_rwsem); |
2182 | ||
1da177e4 LT |
2183 | minimum = time = 0; |
2184 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2185 | if (!ldata->icanon) { |
1da177e4 LT |
2186 | minimum = MIN_CHAR(tty); |
2187 | if (minimum) { | |
a6e54319 | 2188 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2189 | } else { |
a6e54319 | 2190 | timeout = (HZ / 10) * TIME_CHAR(tty); |
33d71363 | 2191 | minimum = 1; |
1da177e4 LT |
2192 | } |
2193 | } | |
2194 | ||
64d608db | 2195 | packet = tty->ctrl.packet; |
947d66b6 | 2196 | old_tail = ldata->read_tail; |
1da177e4 LT |
2197 | |
2198 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2199 | while (nr) { |
2200 | /* First test for status change. */ | |
64d608db | 2201 | if (packet && tty->link->ctrl.pktstatus) { |
1da177e4 | 2202 | unsigned char cs; |
3b830a9c | 2203 | if (kb != kbuf) |
1da177e4 | 2204 | break; |
64d608db JS |
2205 | spin_lock_irq(&tty->link->ctrl.lock); |
2206 | cs = tty->link->ctrl.pktstatus; | |
2207 | tty->link->ctrl.pktstatus = 0; | |
2208 | spin_unlock_irq(&tty->link->ctrl.lock); | |
3b830a9c | 2209 | *kb++ = cs; |
1da177e4 LT |
2210 | nr--; |
2211 | break; | |
2212 | } | |
4edf1827 | 2213 | |
1da177e4 | 2214 | if (!input_available_p(tty, 0)) { |
52bce7f8 | 2215 | up_read(&tty->termios_rwsem); |
0f40fbbc BB |
2216 | tty_buffer_flush_work(tty->port); |
2217 | down_read(&tty->termios_rwsem); | |
2218 | if (!input_available_p(tty, 0)) { | |
2219 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
2220 | retval = -EIO; | |
2221 | break; | |
2222 | } | |
2223 | if (tty_hung_up_p(file)) | |
2224 | break; | |
28b0f8a6 TH |
2225 | /* |
2226 | * Abort readers for ttys which never actually | |
2227 | * get hung up. See __tty_hangup(). | |
2228 | */ | |
2229 | if (test_bit(TTY_HUPPING, &tty->flags)) | |
2230 | break; | |
0f40fbbc BB |
2231 | if (!timeout) |
2232 | break; | |
c96cf923 | 2233 | if (tty_io_nonblock(tty, file)) { |
0f40fbbc BB |
2234 | retval = -EAGAIN; |
2235 | break; | |
2236 | } | |
2237 | if (signal_pending(current)) { | |
2238 | retval = -ERESTARTSYS; | |
2239 | break; | |
2240 | } | |
2241 | up_read(&tty->termios_rwsem); | |
9356b535 | 2242 | |
0f40fbbc BB |
2243 | timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, |
2244 | timeout); | |
9356b535 | 2245 | |
0f40fbbc BB |
2246 | down_read(&tty->termios_rwsem); |
2247 | continue; | |
2248 | } | |
1da177e4 LT |
2249 | } |
2250 | ||
53c5ee2c | 2251 | if (ldata->icanon && !L_EXTPROC(tty)) { |
d7fe75cb LT |
2252 | if (canon_copy_from_read_buf(tty, &kb, &nr)) |
2253 | goto more_to_be_read; | |
1da177e4 | 2254 | } else { |
95ea90db | 2255 | /* Deal with packet mode. */ |
3b830a9c LT |
2256 | if (packet && kb == kbuf) { |
2257 | *kb++ = TIOCPKT_DATA; | |
95ea90db PH |
2258 | nr--; |
2259 | } | |
2260 | ||
15ea8ae8 LT |
2261 | /* |
2262 | * Copy data, and if there is more to be had | |
2263 | * and we have nothing more to wait for, then | |
2264 | * let's mark us for retries. | |
2265 | * | |
2266 | * NOTE! We return here with both the termios_sem | |
2267 | * and atomic_read_lock still held, the retries | |
2268 | * will release them when done. | |
2269 | */ | |
2270 | if (copy_from_read_buf(tty, &kb, &nr) && kb - kbuf >= minimum) { | |
d7fe75cb | 2271 | more_to_be_read: |
15ea8ae8 LT |
2272 | remove_wait_queue(&tty->read_wait, &wait); |
2273 | *cookie = cookie; | |
2274 | return kb - kbuf; | |
1da177e4 LT |
2275 | } |
2276 | } | |
2277 | ||
6367ca72 | 2278 | n_tty_check_unthrottle(tty); |
1da177e4 | 2279 | |
3b830a9c | 2280 | if (kb - kbuf >= minimum) |
1da177e4 LT |
2281 | break; |
2282 | if (time) | |
2283 | timeout = time; | |
2284 | } | |
947d66b6 | 2285 | if (old_tail != ldata->read_tail) |
2c5dc464 | 2286 | n_tty_kick_worker(tty); |
42458f41 PH |
2287 | up_read(&tty->termios_rwsem); |
2288 | ||
1da177e4 | 2289 | remove_wait_queue(&tty->read_wait, &wait); |
aebf0453 PH |
2290 | mutex_unlock(&ldata->atomic_read_lock); |
2291 | ||
3b830a9c LT |
2292 | if (kb - kbuf) |
2293 | retval = kb - kbuf; | |
1da177e4 LT |
2294 | |
2295 | return retval; | |
2296 | } | |
2297 | ||
2298 | /** | |
98629663 JS |
2299 | * n_tty_write - write function for tty |
2300 | * @tty: tty device | |
2301 | * @file: file object | |
2302 | * @buf: userspace buffer pointer | |
2303 | * @nr: size of I/O | |
2304 | * | |
2305 | * Write function of the terminal device. This is serialized with respect to | |
2306 | * other write callers but not to termios changes, reads and other such events. | |
2307 | * Since the receive code will echo characters, thus calling driver write | |
2308 | * methods, the %output_lock is used in the output processing functions called | |
2309 | * here as well as in the echo processing function to protect the column state | |
2310 | * and space left in the buffer. | |
2311 | * | |
2312 | * This code must be sure never to sleep through a hangup. | |
2313 | * | |
2314 | * Locking: output_lock to protect column state and space left | |
2315 | * (note that the process_output*() functions take this lock themselves) | |
1da177e4 | 2316 | */ |
4edf1827 | 2317 | |
11a96d18 | 2318 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2319 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2320 | { |
2321 | const unsigned char *b = buf; | |
97d9e28d | 2322 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2323 | int c; |
2324 | ssize_t retval = 0; | |
2325 | ||
2326 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
9f12e37c | 2327 | if (L_TOSTOP(tty) && file->f_op->write_iter != redirected_tty_write) { |
1da177e4 LT |
2328 | retval = tty_check_change(tty); |
2329 | if (retval) | |
2330 | return retval; | |
2331 | } | |
2332 | ||
9356b535 PH |
2333 | down_read(&tty->termios_rwsem); |
2334 | ||
a88a69c9 JP |
2335 | /* Write out any echoed characters that are still pending */ |
2336 | process_echoes(tty); | |
300a6204 | 2337 | |
1da177e4 LT |
2338 | add_wait_queue(&tty->write_wait, &wait); |
2339 | while (1) { | |
1da177e4 LT |
2340 | if (signal_pending(current)) { |
2341 | retval = -ERESTARTSYS; | |
2342 | break; | |
2343 | } | |
2344 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2345 | retval = -EIO; | |
2346 | break; | |
2347 | } | |
582f5590 | 2348 | if (O_OPOST(tty)) { |
1da177e4 | 2349 | while (nr > 0) { |
a88a69c9 | 2350 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2351 | if (num < 0) { |
2352 | if (num == -EAGAIN) | |
2353 | break; | |
2354 | retval = num; | |
2355 | goto break_out; | |
2356 | } | |
2357 | b += num; | |
2358 | nr -= num; | |
2359 | if (nr == 0) | |
2360 | break; | |
2361 | c = *b; | |
a88a69c9 | 2362 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2363 | break; |
2364 | b++; nr--; | |
2365 | } | |
f34d7a5b AC |
2366 | if (tty->ops->flush_chars) |
2367 | tty->ops->flush_chars(tty); | |
1da177e4 | 2368 | } else { |
4291086b PH |
2369 | struct n_tty_data *ldata = tty->disc_data; |
2370 | ||
d6afe27b | 2371 | while (nr > 0) { |
4291086b | 2372 | mutex_lock(&ldata->output_lock); |
f34d7a5b | 2373 | c = tty->ops->write(tty, b, nr); |
4291086b | 2374 | mutex_unlock(&ldata->output_lock); |
d6afe27b RZ |
2375 | if (c < 0) { |
2376 | retval = c; | |
2377 | goto break_out; | |
2378 | } | |
2379 | if (!c) | |
2380 | break; | |
2381 | b += c; | |
2382 | nr -= c; | |
1da177e4 | 2383 | } |
1da177e4 LT |
2384 | } |
2385 | if (!nr) | |
2386 | break; | |
c96cf923 | 2387 | if (tty_io_nonblock(tty, file)) { |
1da177e4 LT |
2388 | retval = -EAGAIN; |
2389 | break; | |
2390 | } | |
9356b535 PH |
2391 | up_read(&tty->termios_rwsem); |
2392 | ||
97d9e28d | 2393 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
9356b535 PH |
2394 | |
2395 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2396 | } |
2397 | break_out: | |
1da177e4 | 2398 | remove_wait_queue(&tty->write_wait, &wait); |
87108bc9 | 2399 | if (nr && tty->fasync) |
ff8cb0fd | 2400 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
9356b535 | 2401 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2402 | return (b - buf) ? b - buf : retval; |
2403 | } | |
2404 | ||
2405 | /** | |
98629663 JS |
2406 | * n_tty_poll - poll method for N_TTY |
2407 | * @tty: terminal device | |
2408 | * @file: file accessing it | |
2409 | * @wait: poll table | |
1da177e4 | 2410 | * |
98629663 JS |
2411 | * Called when the line discipline is asked to poll() for data or for special |
2412 | * events. This code is not serialized with respect to other events save | |
2413 | * open/close. | |
1da177e4 | 2414 | * |
98629663 JS |
2415 | * This code must be sure never to sleep through a hangup. |
2416 | * | |
2417 | * Locking: called without the kernel lock held -- fine. | |
1da177e4 | 2418 | */ |
afc9a42b | 2419 | static __poll_t n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2420 | poll_table *wait) |
1da177e4 | 2421 | { |
afc9a42b | 2422 | __poll_t mask = 0; |
1da177e4 LT |
2423 | |
2424 | poll_wait(file, &tty->read_wait, wait); | |
2425 | poll_wait(file, &tty->write_wait, wait); | |
eafbe67f | 2426 | if (input_available_p(tty, 1)) |
a9a08845 | 2427 | mask |= EPOLLIN | EPOLLRDNORM; |
0f40fbbc BB |
2428 | else { |
2429 | tty_buffer_flush_work(tty->port); | |
2430 | if (input_available_p(tty, 1)) | |
a9a08845 | 2431 | mask |= EPOLLIN | EPOLLRDNORM; |
0f40fbbc | 2432 | } |
64d608db | 2433 | if (tty->ctrl.packet && tty->link->ctrl.pktstatus) |
a9a08845 | 2434 | mask |= EPOLLPRI | EPOLLIN | EPOLLRDNORM; |
0f40fbbc | 2435 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) |
a9a08845 | 2436 | mask |= EPOLLHUP; |
1da177e4 | 2437 | if (tty_hung_up_p(file)) |
a9a08845 | 2438 | mask |= EPOLLHUP; |
f34d7a5b AC |
2439 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2440 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2441 | tty_write_room(tty) > 0) | |
a9a08845 | 2442 | mask |= EPOLLOUT | EPOLLWRNORM; |
1da177e4 LT |
2443 | return mask; |
2444 | } | |
2445 | ||
57c94121 | 2446 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2447 | { |
bc5a5e3f | 2448 | size_t nr, head, tail; |
47afa7a5 | 2449 | |
a73d3d69 | 2450 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2451 | return 0; |
ba2e68ac JS |
2452 | head = ldata->canon_head; |
2453 | tail = ldata->read_tail; | |
bc5a5e3f | 2454 | nr = head - tail; |
47afa7a5 | 2455 | /* Skip EOF-chars.. */ |
3d63b7e4 | 2456 | while (MASK(head) != MASK(tail)) { |
bc5a5e3f PH |
2457 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2458 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2459 | nr--; |
bc5a5e3f | 2460 | tail++; |
47afa7a5 AC |
2461 | } |
2462 | return nr; | |
2463 | } | |
2464 | ||
d78328bc JS |
2465 | static int n_tty_ioctl(struct tty_struct *tty, unsigned int cmd, |
2466 | unsigned long arg) | |
47afa7a5 | 2467 | { |
ba2e68ac | 2468 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2469 | int retval; |
2470 | ||
2471 | switch (cmd) { | |
2472 | case TIOCOUTQ: | |
2473 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2474 | case TIOCINQ: | |
6d76bd26 | 2475 | down_write(&tty->termios_rwsem); |
966031f3 | 2476 | if (L_ICANON(tty) && !L_EXTPROC(tty)) |
57c94121 | 2477 | retval = inq_canon(ldata); |
6d76bd26 PH |
2478 | else |
2479 | retval = read_cnt(ldata); | |
2480 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2481 | return put_user(retval, (unsigned int __user *) arg); |
2482 | default: | |
7c783601 | 2483 | return n_tty_ioctl_helper(tty, cmd, arg); |
47afa7a5 AC |
2484 | } |
2485 | } | |
2486 | ||
27228732 | 2487 | static struct tty_ldisc_ops n_tty_ops = { |
5e30d3bf | 2488 | .owner = THIS_MODULE, |
fbadf70a | 2489 | .num = N_TTY, |
e10cc1df PF |
2490 | .name = "n_tty", |
2491 | .open = n_tty_open, | |
2492 | .close = n_tty_close, | |
2493 | .flush_buffer = n_tty_flush_buffer, | |
11a96d18 AC |
2494 | .read = n_tty_read, |
2495 | .write = n_tty_write, | |
e10cc1df PF |
2496 | .ioctl = n_tty_ioctl, |
2497 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2498 | .poll = n_tty_poll, |
e10cc1df | 2499 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 | 2500 | .write_wakeup = n_tty_write_wakeup, |
24a89d1c | 2501 | .receive_buf2 = n_tty_receive_buf2, |
6bb6fa69 | 2502 | .lookahead_buf = n_tty_lookahead_flow_ctrl, |
1da177e4 | 2503 | }; |
572b9adb RG |
2504 | |
2505 | /** | |
2506 | * n_tty_inherit_ops - inherit N_TTY methods | |
2507 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2508 | * | |
27228732 | 2509 | * Enables a 'subclass' line discipline to 'inherit' N_TTY methods. |
572b9adb RG |
2510 | */ |
2511 | ||
2512 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2513 | { | |
27228732 | 2514 | *ops = n_tty_ops; |
572b9adb | 2515 | ops->owner = NULL; |
572b9adb RG |
2516 | } |
2517 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); | |
27228732 PH |
2518 | |
2519 | void __init n_tty_init(void) | |
2520 | { | |
fbadf70a | 2521 | tty_register_ldisc(&n_tty_ops); |
27228732 | 2522 | } |