Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * n_tty.c --- implements the N_TTY line discipline. | |
4edf1827 | 3 | * |
1da177e4 LT |
4 | * This code used to be in tty_io.c, but things are getting hairy |
5 | * enough that it made sense to split things off. (The N_TTY | |
6 | * processing has changed so much that it's hardly recognizable, | |
7 | * anyway...) | |
8 | * | |
9 | * Note that the open routine for N_TTY is guaranteed never to return | |
10 | * an error. This is because Linux will fall back to setting a line | |
4edf1827 | 11 | * to N_TTY if it can not switch to any other line discipline. |
1da177e4 LT |
12 | * |
13 | * Written by Theodore Ts'o, Copyright 1994. | |
4edf1827 | 14 | * |
1da177e4 LT |
15 | * This file also contains code originally written by Linus Torvalds, |
16 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. | |
4edf1827 | 17 | * |
1da177e4 LT |
18 | * This file may be redistributed under the terms of the GNU General Public |
19 | * License. | |
20 | * | |
21 | * Reduced memory usage for older ARM systems - Russell King. | |
22 | * | |
4edf1827 | 23 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
1da177e4 LT |
24 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
25 | * who actually finally proved there really was a race. | |
26 | * | |
27 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to | |
28 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. | |
11a96d18 | 29 | * Also fixed a bug in BLOCKING mode where n_tty_write returns |
1da177e4 LT |
30 | * EAGAIN |
31 | */ | |
32 | ||
33 | #include <linux/types.h> | |
34 | #include <linux/major.h> | |
35 | #include <linux/errno.h> | |
36 | #include <linux/signal.h> | |
37 | #include <linux/fcntl.h> | |
38 | #include <linux/sched.h> | |
39 | #include <linux/interrupt.h> | |
40 | #include <linux/tty.h> | |
41 | #include <linux/timer.h> | |
42 | #include <linux/ctype.h> | |
43 | #include <linux/mm.h> | |
44 | #include <linux/string.h> | |
45 | #include <linux/slab.h> | |
46 | #include <linux/poll.h> | |
47 | #include <linux/bitops.h> | |
522ed776 MT |
48 | #include <linux/audit.h> |
49 | #include <linux/file.h> | |
300a6204 | 50 | #include <linux/uaccess.h> |
572b9adb | 51 | #include <linux/module.h> |
593fb1ae | 52 | #include <linux/ratelimit.h> |
86e35aea | 53 | #include <linux/vmalloc.h> |
1da177e4 | 54 | |
1da177e4 LT |
55 | |
56 | /* number of characters left in xmit buffer before select has we have room */ | |
57 | #define WAKEUP_CHARS 256 | |
58 | ||
59 | /* | |
60 | * This defines the low- and high-watermarks for throttling and | |
61 | * unthrottling the TTY driver. These watermarks are used for | |
62 | * controlling the space in the read buffer. | |
63 | */ | |
64 | #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ | |
bbd20759 | 65 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
1da177e4 | 66 | |
a88a69c9 JP |
67 | /* |
68 | * Special byte codes used in the echo buffer to represent operations | |
69 | * or special handling of characters. Bytes in the echo buffer that | |
70 | * are not part of such special blocks are treated as normal character | |
71 | * codes. | |
72 | */ | |
73 | #define ECHO_OP_START 0xff | |
74 | #define ECHO_OP_MOVE_BACK_COL 0x80 | |
75 | #define ECHO_OP_SET_CANON_COL 0x81 | |
76 | #define ECHO_OP_ERASE_TAB 0x82 | |
77 | ||
cbfd0340 PH |
78 | #define ECHO_COMMIT_WATERMARK 256 |
79 | #define ECHO_BLOCK 256 | |
80 | #define ECHO_DISCARD_WATERMARK N_TTY_BUF_SIZE - (ECHO_BLOCK + 32) | |
81 | ||
82 | ||
32f13521 PH |
83 | #undef N_TTY_TRACE |
84 | #ifdef N_TTY_TRACE | |
85 | # define n_tty_trace(f, args...) trace_printk(f, ##args) | |
86 | #else | |
87 | # define n_tty_trace(f, args...) | |
88 | #endif | |
89 | ||
70ece7a7 | 90 | struct n_tty_data { |
fb7aa03d PH |
91 | /* producer-published */ |
92 | size_t read_head; | |
70aca71f | 93 | size_t commit_head; |
fb7aa03d | 94 | size_t canon_head; |
9dfd16dd PH |
95 | size_t echo_head; |
96 | size_t echo_commit; | |
1075a6e2 | 97 | size_t echo_mark; |
1bb9d562 | 98 | DECLARE_BITMAP(char_map, 256); |
fb7aa03d PH |
99 | |
100 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c JS |
101 | unsigned long overrun_time; |
102 | int num_overrun; | |
103 | ||
24a89d1c PH |
104 | /* non-atomic */ |
105 | bool no_room; | |
106 | ||
fb7aa03d | 107 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c | 108 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
4d0ed182 | 109 | unsigned char push:1; |
3fe780b3 | 110 | |
fb7aa03d | 111 | /* shared by producer and consumer */ |
20bafb3d | 112 | char read_buf[N_TTY_BUF_SIZE]; |
3fe780b3 | 113 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
20bafb3d | 114 | unsigned char echo_buf[N_TTY_BUF_SIZE]; |
ba2e68ac | 115 | |
f6c8dbe6 | 116 | int minimum_to_wake; |
ba2e68ac | 117 | |
fb7aa03d PH |
118 | /* consumer-published */ |
119 | size_t read_tail; | |
40d5e090 | 120 | size_t line_start; |
fb7aa03d | 121 | |
fb7aa03d PH |
122 | /* protected by output lock */ |
123 | unsigned int column; | |
ba2e68ac | 124 | unsigned int canon_column; |
9dfd16dd | 125 | size_t echo_tail; |
bddc7152 JS |
126 | |
127 | struct mutex atomic_read_lock; | |
128 | struct mutex output_lock; | |
70ece7a7 JS |
129 | }; |
130 | ||
ce74117a PH |
131 | static inline size_t read_cnt(struct n_tty_data *ldata) |
132 | { | |
a2f73be8 | 133 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
134 | } |
135 | ||
bc5a5e3f PH |
136 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
137 | { | |
138 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
139 | } | |
140 | ||
141 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
142 | { | |
143 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
144 | } | |
145 | ||
addaebcc PH |
146 | static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) |
147 | { | |
148 | return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
149 | } | |
150 | ||
151 | static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) | |
152 | { | |
153 | return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
154 | } | |
155 | ||
522ed776 MT |
156 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
157 | unsigned char __user *ptr) | |
158 | { | |
53c5ee2c JS |
159 | struct n_tty_data *ldata = tty->disc_data; |
160 | ||
161 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
162 | return put_user(x, ptr); |
163 | } | |
164 | ||
679e7c29 PH |
165 | static int tty_copy_to_user(struct tty_struct *tty, void __user *to, |
166 | size_t tail, size_t n) | |
72586c60 LA |
167 | { |
168 | struct n_tty_data *ldata = tty->disc_data; | |
679e7c29 PH |
169 | size_t size = N_TTY_BUF_SIZE - tail; |
170 | const void *from = read_buf_addr(ldata, tail); | |
171 | int uncopied; | |
172 | ||
173 | if (n > size) { | |
174 | tty_audit_add_data(tty, from, size, ldata->icanon); | |
175 | uncopied = copy_to_user(to, from, size); | |
176 | if (uncopied) | |
177 | return uncopied; | |
178 | to += size; | |
179 | n -= size; | |
180 | from = ldata->read_buf; | |
181 | } | |
72586c60 | 182 | |
6b2a3d62 | 183 | tty_audit_add_data(tty, from, n, ldata->icanon); |
72586c60 LA |
184 | return copy_to_user(to, from, n); |
185 | } | |
186 | ||
24a89d1c | 187 | /** |
2c5dc464 | 188 | * n_tty_kick_worker - start input worker (if required) |
24a89d1c PH |
189 | * @tty: terminal |
190 | * | |
2c5dc464 | 191 | * Re-schedules the flip buffer work if it may have stopped |
24a89d1c | 192 | * |
6d76bd26 PH |
193 | * Caller holds exclusive termios_rwsem |
194 | * or | |
195 | * n_tty_read()/consumer path: | |
196 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
197 | */ |
198 | ||
2c5dc464 | 199 | static void n_tty_kick_worker(struct tty_struct *tty) |
7879a9f9 | 200 | { |
24a89d1c PH |
201 | struct n_tty_data *ldata = tty->disc_data; |
202 | ||
2c5dc464 PH |
203 | /* Did the input worker stop? Restart it */ |
204 | if (unlikely(ldata->no_room)) { | |
24a89d1c PH |
205 | ldata->no_room = 0; |
206 | ||
ecbbfd44 | 207 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 208 | "scheduling with invalid itty\n"); |
21622939 PH |
209 | /* see if ldisc has been killed - if so, this means that |
210 | * even though the ldisc has been halted and ->buf.work | |
211 | * cancelled, ->buf.work is about to be rescheduled | |
212 | */ | |
213 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
214 | "scheduling buffer work for halted ldisc\n"); | |
e176058f | 215 | tty_buffer_restart_work(tty->port); |
ecbbfd44 | 216 | } |
55db4c64 LT |
217 | } |
218 | ||
9a4aec2d PH |
219 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
220 | { | |
221 | struct n_tty_data *ldata = tty->disc_data; | |
222 | ssize_t n = 0; | |
223 | ||
224 | if (!ldata->icanon) | |
70aca71f | 225 | n = ldata->commit_head - ldata->read_tail; |
9a4aec2d PH |
226 | else |
227 | n = ldata->canon_head - ldata->read_tail; | |
228 | return n; | |
229 | } | |
230 | ||
ee0bab83 PH |
231 | /** |
232 | * n_tty_write_wakeup - asynchronous I/O notifier | |
233 | * @tty: tty device | |
234 | * | |
235 | * Required for the ptys, serial driver etc. since processes | |
236 | * that attach themselves to the master and rely on ASYNC | |
237 | * IO must be woken up | |
238 | */ | |
239 | ||
240 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
241 | { | |
242 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) | |
243 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
244 | } | |
245 | ||
4a23a4df | 246 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 247 | { |
a342846f PH |
248 | struct n_tty_data *ldata = tty->disc_data; |
249 | ||
6367ca72 PH |
250 | /* |
251 | * Check the remaining room for the input canonicalization | |
252 | * mode. We don't want to throttle the driver if we're in | |
253 | * canonical mode and don't have a newline yet! | |
254 | */ | |
a342846f PH |
255 | if (ldata->icanon && ldata->canon_head == ldata->read_tail) |
256 | return; | |
257 | ||
6367ca72 PH |
258 | while (1) { |
259 | int throttled; | |
260 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
5e28cca1 | 261 | if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE) |
6367ca72 PH |
262 | break; |
263 | throttled = tty_throttle_safe(tty); | |
264 | if (!throttled) | |
265 | break; | |
266 | } | |
267 | __tty_set_flow_change(tty, 0); | |
268 | } | |
269 | ||
4b293492 | 270 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 271 | { |
6d27a63c | 272 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { |
3afb1b39 PH |
273 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) |
274 | return; | |
275 | if (!tty->count) | |
276 | return; | |
2c5dc464 | 277 | n_tty_kick_worker(tty); |
6d27a63c | 278 | tty_wakeup(tty->link); |
3afb1b39 PH |
279 | return; |
280 | } | |
281 | ||
6367ca72 PH |
282 | /* If there is enough space in the read buffer now, let the |
283 | * low-level driver know. We use chars_in_buffer() to | |
284 | * check the buffer, as it now knows about canonical mode. | |
285 | * Otherwise, if the driver is throttled and the line is | |
286 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
287 | * we won't get any more characters. | |
288 | */ | |
289 | ||
290 | while (1) { | |
291 | int unthrottled; | |
292 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
293 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
294 | break; | |
295 | if (!tty->count) | |
296 | break; | |
2c5dc464 | 297 | n_tty_kick_worker(tty); |
6367ca72 PH |
298 | unthrottled = tty_unthrottle_safe(tty); |
299 | if (!unthrottled) | |
300 | break; | |
301 | } | |
302 | __tty_set_flow_change(tty, 0); | |
303 | } | |
304 | ||
17b82060 AC |
305 | /** |
306 | * put_tty_queue - add character to tty | |
307 | * @c: character | |
57c94121 | 308 | * @ldata: n_tty data |
17b82060 | 309 | * |
6d76bd26 PH |
310 | * Add a character to the tty read_buf queue. |
311 | * | |
312 | * n_tty_receive_buf()/producer path: | |
313 | * caller holds non-exclusive termios_rwsem | |
17b82060 AC |
314 | */ |
315 | ||
19e2ad6a | 316 | static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 317 | { |
8bfbe2de CR |
318 | *read_buf_addr(ldata, ldata->read_head) = c; |
319 | ldata->read_head++; | |
1da177e4 LT |
320 | } |
321 | ||
1da177e4 LT |
322 | /** |
323 | * reset_buffer_flags - reset buffer state | |
324 | * @tty: terminal to reset | |
325 | * | |
25518c68 PH |
326 | * Reset the read buffer counters and clear the flags. |
327 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 328 | * |
6d76bd26 PH |
329 | * Locking: caller holds exclusive termios_rwsem |
330 | * (or locking is not required) | |
1da177e4 | 331 | */ |
a88a69c9 | 332 | |
b66f4fa5 | 333 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 334 | { |
a73d3d69 | 335 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 336 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
70aca71f | 337 | ldata->commit_head = 0; |
1075a6e2 | 338 | ldata->echo_mark = 0; |
40d5e090 | 339 | ldata->line_start = 0; |
a88a69c9 | 340 | |
a73d3d69 | 341 | ldata->erasing = 0; |
3fe780b3 | 342 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 | 343 | ldata->push = 0; |
1da177e4 LT |
344 | } |
345 | ||
a30737ab PH |
346 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
347 | { | |
348 | unsigned long flags; | |
349 | ||
a30737ab | 350 | if (tty->link->packet) { |
54e8e5fc | 351 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
a30737ab | 352 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; |
54e8e5fc | 353 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
e81107d4 | 354 | wake_up_interruptible(&tty->link->read_wait); |
a30737ab | 355 | } |
a30737ab PH |
356 | } |
357 | ||
1da177e4 LT |
358 | /** |
359 | * n_tty_flush_buffer - clean input queue | |
360 | * @tty: terminal device | |
361 | * | |
25518c68 PH |
362 | * Flush the input buffer. Called when the tty layer wants the |
363 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
364 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 365 | * |
6d76bd26 PH |
366 | * Holds termios_rwsem to exclude producer/consumer while |
367 | * buffer indices are reset. | |
368 | * | |
369 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 370 | */ |
4edf1827 AC |
371 | |
372 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 373 | { |
6d76bd26 | 374 | down_write(&tty->termios_rwsem); |
b66f4fa5 | 375 | reset_buffer_flags(tty->disc_data); |
2c5dc464 | 376 | n_tty_kick_worker(tty); |
4edf1827 | 377 | |
a30737ab PH |
378 | if (tty->link) |
379 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 380 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
381 | } |
382 | ||
1da177e4 LT |
383 | /** |
384 | * is_utf8_continuation - utf8 multibyte check | |
385 | * @c: byte to check | |
386 | * | |
387 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
388 | * character. We use this to correctly compute the on screen size | |
389 | * of the character when printing | |
390 | */ | |
4edf1827 | 391 | |
1da177e4 LT |
392 | static inline int is_utf8_continuation(unsigned char c) |
393 | { | |
394 | return (c & 0xc0) == 0x80; | |
395 | } | |
396 | ||
397 | /** | |
398 | * is_continuation - multibyte check | |
399 | * @c: byte to check | |
400 | * | |
401 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
402 | * character and the terminal is in unicode mode. | |
403 | */ | |
4edf1827 | 404 | |
1da177e4 LT |
405 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
406 | { | |
407 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
408 | } | |
409 | ||
410 | /** | |
a88a69c9 | 411 | * do_output_char - output one character |
1da177e4 LT |
412 | * @c: character (or partial unicode symbol) |
413 | * @tty: terminal device | |
a88a69c9 | 414 | * @space: space available in tty driver write buffer |
1da177e4 | 415 | * |
a88a69c9 JP |
416 | * This is a helper function that handles one output character |
417 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
418 | * doing OPOST processing and putting the results in the |
419 | * tty driver's write buffer. | |
a88a69c9 JP |
420 | * |
421 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
422 | * and NLDLY. They simply aren't relevant in the world today. | |
423 | * If you ever need them, add them here. | |
1da177e4 | 424 | * |
a88a69c9 JP |
425 | * Returns the number of bytes of buffer space used or -1 if |
426 | * no space left. | |
427 | * | |
428 | * Locking: should be called under the output_lock to protect | |
429 | * the column state and space left in the buffer | |
1da177e4 | 430 | */ |
4edf1827 | 431 | |
a88a69c9 | 432 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 433 | { |
53c5ee2c | 434 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 435 | int spaces; |
1da177e4 | 436 | |
1da177e4 LT |
437 | if (!space) |
438 | return -1; | |
300a6204 | 439 | |
a88a69c9 JP |
440 | switch (c) { |
441 | case '\n': | |
442 | if (O_ONLRET(tty)) | |
53c5ee2c | 443 | ldata->column = 0; |
a88a69c9 JP |
444 | if (O_ONLCR(tty)) { |
445 | if (space < 2) | |
446 | return -1; | |
ba2e68ac | 447 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 448 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
449 | return 2; |
450 | } | |
ba2e68ac | 451 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
452 | break; |
453 | case '\r': | |
53c5ee2c | 454 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
455 | return 0; |
456 | if (O_OCRNL(tty)) { | |
457 | c = '\n'; | |
458 | if (O_ONLRET(tty)) | |
ba2e68ac | 459 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 460 | break; |
a88a69c9 | 461 | } |
ba2e68ac | 462 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
463 | break; |
464 | case '\t': | |
53c5ee2c | 465 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
466 | if (O_TABDLY(tty) == XTABS) { |
467 | if (space < spaces) | |
468 | return -1; | |
53c5ee2c | 469 | ldata->column += spaces; |
a88a69c9 JP |
470 | tty->ops->write(tty, " ", spaces); |
471 | return spaces; | |
1da177e4 | 472 | } |
53c5ee2c | 473 | ldata->column += spaces; |
a88a69c9 JP |
474 | break; |
475 | case '\b': | |
53c5ee2c JS |
476 | if (ldata->column > 0) |
477 | ldata->column--; | |
a88a69c9 JP |
478 | break; |
479 | default: | |
a59c0d6f JP |
480 | if (!iscntrl(c)) { |
481 | if (O_OLCUC(tty)) | |
482 | c = toupper(c); | |
483 | if (!is_continuation(c, tty)) | |
53c5ee2c | 484 | ldata->column++; |
a59c0d6f | 485 | } |
a88a69c9 | 486 | break; |
1da177e4 | 487 | } |
a88a69c9 | 488 | |
f34d7a5b | 489 | tty_put_char(tty, c); |
a88a69c9 JP |
490 | return 1; |
491 | } | |
492 | ||
493 | /** | |
494 | * process_output - output post processor | |
495 | * @c: character (or partial unicode symbol) | |
496 | * @tty: terminal device | |
497 | * | |
ee5aa7b8 JP |
498 | * Output one character with OPOST processing. |
499 | * Returns -1 when the output device is full and the character | |
500 | * must be retried. | |
a88a69c9 JP |
501 | * |
502 | * Locking: output_lock to protect column state and space left | |
503 | * (also, this is called from n_tty_write under the | |
504 | * tty layer write lock) | |
505 | */ | |
506 | ||
507 | static int process_output(unsigned char c, struct tty_struct *tty) | |
508 | { | |
bddc7152 | 509 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
510 | int space, retval; |
511 | ||
bddc7152 | 512 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
513 | |
514 | space = tty_write_room(tty); | |
515 | retval = do_output_char(c, tty, space); | |
516 | ||
bddc7152 | 517 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
518 | if (retval < 0) |
519 | return -1; | |
520 | else | |
521 | return 0; | |
1da177e4 LT |
522 | } |
523 | ||
524 | /** | |
a88a69c9 | 525 | * process_output_block - block post processor |
1da177e4 | 526 | * @tty: terminal device |
ee5aa7b8 JP |
527 | * @buf: character buffer |
528 | * @nr: number of bytes to output | |
529 | * | |
530 | * Output a block of characters with OPOST processing. | |
531 | * Returns the number of characters output. | |
1da177e4 LT |
532 | * |
533 | * This path is used to speed up block console writes, among other | |
534 | * things when processing blocks of output data. It handles only | |
535 | * the simple cases normally found and helps to generate blocks of | |
536 | * symbols for the console driver and thus improve performance. | |
537 | * | |
a88a69c9 JP |
538 | * Locking: output_lock to protect column state and space left |
539 | * (also, this is called from n_tty_write under the | |
540 | * tty layer write lock) | |
1da177e4 | 541 | */ |
4edf1827 | 542 | |
a88a69c9 JP |
543 | static ssize_t process_output_block(struct tty_struct *tty, |
544 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 545 | { |
53c5ee2c | 546 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 547 | int space; |
bbd20759 | 548 | int i; |
1da177e4 LT |
549 | const unsigned char *cp; |
550 | ||
bddc7152 | 551 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 552 | |
f34d7a5b | 553 | space = tty_write_room(tty); |
300a6204 | 554 | if (!space) { |
bddc7152 | 555 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 556 | return 0; |
a88a69c9 | 557 | } |
1da177e4 LT |
558 | if (nr > space) |
559 | nr = space; | |
560 | ||
561 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
562 | unsigned char c = *cp; |
563 | ||
564 | switch (c) { | |
1da177e4 LT |
565 | case '\n': |
566 | if (O_ONLRET(tty)) | |
53c5ee2c | 567 | ldata->column = 0; |
1da177e4 LT |
568 | if (O_ONLCR(tty)) |
569 | goto break_out; | |
ba2e68ac | 570 | ldata->canon_column = ldata->column; |
1da177e4 LT |
571 | break; |
572 | case '\r': | |
53c5ee2c | 573 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
574 | goto break_out; |
575 | if (O_OCRNL(tty)) | |
576 | goto break_out; | |
ba2e68ac | 577 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
578 | break; |
579 | case '\t': | |
580 | goto break_out; | |
581 | case '\b': | |
53c5ee2c JS |
582 | if (ldata->column > 0) |
583 | ldata->column--; | |
1da177e4 LT |
584 | break; |
585 | default: | |
a59c0d6f JP |
586 | if (!iscntrl(c)) { |
587 | if (O_OLCUC(tty)) | |
588 | goto break_out; | |
589 | if (!is_continuation(c, tty)) | |
53c5ee2c | 590 | ldata->column++; |
a59c0d6f | 591 | } |
1da177e4 LT |
592 | break; |
593 | } | |
594 | } | |
595 | break_out: | |
f34d7a5b | 596 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 597 | |
bddc7152 | 598 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
599 | return i; |
600 | } | |
601 | ||
a88a69c9 JP |
602 | /** |
603 | * process_echoes - write pending echo characters | |
604 | * @tty: terminal device | |
605 | * | |
606 | * Write previously buffered echo (and other ldisc-generated) | |
607 | * characters to the tty. | |
608 | * | |
609 | * Characters generated by the ldisc (including echoes) need to | |
610 | * be buffered because the driver's write buffer can fill during | |
611 | * heavy program output. Echoing straight to the driver will | |
612 | * often fail under these conditions, causing lost characters and | |
613 | * resulting mismatches of ldisc state information. | |
614 | * | |
615 | * Since the ldisc state must represent the characters actually sent | |
616 | * to the driver at the time of the write, operations like certain | |
617 | * changes in column state are also saved in the buffer and executed | |
618 | * here. | |
619 | * | |
620 | * A circular fifo buffer is used so that the most recent characters | |
621 | * are prioritized. Also, when control characters are echoed with a | |
622 | * prefixed "^", the pair is treated atomically and thus not separated. | |
623 | * | |
019ebdf9 | 624 | * Locking: callers must hold output_lock |
a88a69c9 JP |
625 | */ |
626 | ||
bc5b1ec5 | 627 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 628 | { |
53c5ee2c | 629 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 630 | int space, old_space; |
addaebcc | 631 | size_t tail; |
a88a69c9 | 632 | unsigned char c; |
a88a69c9 | 633 | |
bc5b1ec5 | 634 | old_space = space = tty_write_room(tty); |
a88a69c9 | 635 | |
addaebcc | 636 | tail = ldata->echo_tail; |
29c7c5ca | 637 | while (ldata->echo_commit != tail) { |
addaebcc | 638 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
639 | if (c == ECHO_OP_START) { |
640 | unsigned char op; | |
a88a69c9 JP |
641 | int no_space_left = 0; |
642 | ||
643 | /* | |
644 | * If the buffer byte is the start of a multi-byte | |
645 | * operation, get the next byte, which is either the | |
646 | * op code or a control character value. | |
647 | */ | |
addaebcc | 648 | op = echo_buf(ldata, tail + 1); |
300a6204 | 649 | |
a88a69c9 JP |
650 | switch (op) { |
651 | unsigned int num_chars, num_bs; | |
652 | ||
653 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 654 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
655 | |
656 | /* | |
657 | * Determine how many columns to go back | |
658 | * in order to erase the tab. | |
659 | * This depends on the number of columns | |
660 | * used by other characters within the tab | |
661 | * area. If this (modulo 8) count is from | |
662 | * the start of input rather than from a | |
663 | * previous tab, we offset by canon column. | |
664 | * Otherwise, tab spacing is normal. | |
665 | */ | |
666 | if (!(num_chars & 0x80)) | |
ba2e68ac | 667 | num_chars += ldata->canon_column; |
a88a69c9 JP |
668 | num_bs = 8 - (num_chars & 7); |
669 | ||
670 | if (num_bs > space) { | |
671 | no_space_left = 1; | |
672 | break; | |
673 | } | |
674 | space -= num_bs; | |
675 | while (num_bs--) { | |
676 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
677 | if (ldata->column > 0) |
678 | ldata->column--; | |
a88a69c9 | 679 | } |
addaebcc | 680 | tail += 3; |
a88a69c9 JP |
681 | break; |
682 | ||
683 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 684 | ldata->canon_column = ldata->column; |
addaebcc | 685 | tail += 2; |
a88a69c9 JP |
686 | break; |
687 | ||
688 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
689 | if (ldata->column > 0) |
690 | ldata->column--; | |
addaebcc | 691 | tail += 2; |
a88a69c9 JP |
692 | break; |
693 | ||
694 | case ECHO_OP_START: | |
695 | /* This is an escaped echo op start code */ | |
696 | if (!space) { | |
697 | no_space_left = 1; | |
698 | break; | |
699 | } | |
700 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 701 | ldata->column++; |
a88a69c9 | 702 | space--; |
addaebcc | 703 | tail += 2; |
a88a69c9 JP |
704 | break; |
705 | ||
706 | default: | |
a88a69c9 | 707 | /* |
62b26358 JP |
708 | * If the op is not a special byte code, |
709 | * it is a ctrl char tagged to be echoed | |
710 | * as "^X" (where X is the letter | |
711 | * representing the control char). | |
712 | * Note that we must ensure there is | |
713 | * enough space for the whole ctrl pair. | |
714 | * | |
a88a69c9 | 715 | */ |
62b26358 JP |
716 | if (space < 2) { |
717 | no_space_left = 1; | |
718 | break; | |
719 | } | |
720 | tty_put_char(tty, '^'); | |
721 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 722 | ldata->column += 2; |
62b26358 | 723 | space -= 2; |
addaebcc | 724 | tail += 2; |
a88a69c9 JP |
725 | } |
726 | ||
727 | if (no_space_left) | |
728 | break; | |
729 | } else { | |
582f5590 | 730 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
731 | int retval = do_output_char(c, tty, space); |
732 | if (retval < 0) | |
733 | break; | |
734 | space -= retval; | |
735 | } else { | |
736 | if (!space) | |
737 | break; | |
738 | tty_put_char(tty, c); | |
739 | space -= 1; | |
740 | } | |
addaebcc | 741 | tail += 1; |
a88a69c9 | 742 | } |
a88a69c9 JP |
743 | } |
744 | ||
cbfd0340 PH |
745 | /* If the echo buffer is nearly full (so that the possibility exists |
746 | * of echo overrun before the next commit), then discard enough | |
747 | * data at the tail to prevent a subsequent overrun */ | |
748 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 749 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 750 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
751 | tail += 3; |
752 | else | |
753 | tail += 2; | |
754 | } else | |
755 | tail++; | |
756 | } | |
757 | ||
addaebcc | 758 | ldata->echo_tail = tail; |
bc5b1ec5 | 759 | return old_space - space; |
019ebdf9 PH |
760 | } |
761 | ||
762 | static void commit_echoes(struct tty_struct *tty) | |
763 | { | |
764 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 765 | size_t nr, old, echoed; |
cbfd0340 PH |
766 | size_t head; |
767 | ||
768 | head = ldata->echo_head; | |
1075a6e2 | 769 | ldata->echo_mark = head; |
cbfd0340 PH |
770 | old = ldata->echo_commit - ldata->echo_tail; |
771 | ||
772 | /* Process committed echoes if the accumulated # of bytes | |
773 | * is over the threshold (and try again each time another | |
774 | * block is accumulated) */ | |
775 | nr = head - ldata->echo_tail; | |
776 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
777 | return; | |
a88a69c9 | 778 | |
019ebdf9 | 779 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 780 | ldata->echo_commit = head; |
bc5b1ec5 | 781 | echoed = __process_echoes(tty); |
bddc7152 | 782 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 783 | |
bc5b1ec5 | 784 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
785 | tty->ops->flush_chars(tty); |
786 | } | |
787 | ||
019ebdf9 | 788 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
789 | { |
790 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 791 | size_t echoed; |
17bd7907 | 792 | |
e2613be5 | 793 | if (ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
794 | return; |
795 | ||
796 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 797 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 798 | echoed = __process_echoes(tty); |
019ebdf9 PH |
799 | mutex_unlock(&ldata->output_lock); |
800 | ||
bc5b1ec5 | 801 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 802 | tty->ops->flush_chars(tty); |
17bd7907 PH |
803 | } |
804 | ||
1075a6e2 | 805 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
806 | static void flush_echoes(struct tty_struct *tty) |
807 | { | |
808 | struct n_tty_data *ldata = tty->disc_data; | |
809 | ||
39434abd PH |
810 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
811 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
812 | return; |
813 | ||
814 | mutex_lock(&ldata->output_lock); | |
815 | ldata->echo_commit = ldata->echo_head; | |
816 | __process_echoes(tty); | |
817 | mutex_unlock(&ldata->output_lock); | |
818 | } | |
819 | ||
a88a69c9 JP |
820 | /** |
821 | * add_echo_byte - add a byte to the echo buffer | |
822 | * @c: unicode byte to echo | |
57c94121 | 823 | * @ldata: n_tty data |
a88a69c9 JP |
824 | * |
825 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
826 | */ |
827 | ||
cbfd0340 | 828 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 829 | { |
addaebcc | 830 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
831 | } |
832 | ||
833 | /** | |
834 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 835 | * @ldata: n_tty data |
a88a69c9 JP |
836 | * |
837 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
838 | */ |
839 | ||
57c94121 | 840 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 841 | { |
57c94121 JS |
842 | add_echo_byte(ECHO_OP_START, ldata); |
843 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
844 | } |
845 | ||
846 | /** | |
847 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 848 | * @ldata: n_tty data |
a88a69c9 JP |
849 | * |
850 | * Add an operation to the echo buffer to set the canon column | |
851 | * to the current column. | |
a88a69c9 JP |
852 | */ |
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 | /** | |
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 | |
57c94121 | 864 | * @ldata: n_tty data |
a88a69c9 JP |
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 | |
869 | * columns have been used since either a previous tab or the start | |
870 | * of input. This information will be used later, along with | |
871 | * canon column (if applicable), to go back the correct number | |
872 | * of columns. | |
a88a69c9 JP |
873 | */ |
874 | ||
875 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 876 | struct n_tty_data *ldata) |
a88a69c9 | 877 | { |
57c94121 JS |
878 | add_echo_byte(ECHO_OP_START, ldata); |
879 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
880 | |
881 | /* We only need to know this modulo 8 (tab spacing) */ | |
882 | num_chars &= 7; | |
883 | ||
884 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
885 | if (after_tab) | |
886 | num_chars |= 0x80; | |
300a6204 | 887 | |
57c94121 | 888 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
889 | } |
890 | ||
891 | /** | |
892 | * echo_char_raw - echo a character raw | |
893 | * @c: unicode byte to echo | |
894 | * @tty: terminal device | |
895 | * | |
896 | * Echo user input back onto the screen. This must be called only when | |
897 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
898 | * | |
899 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
900 | */ |
901 | ||
57c94121 | 902 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 903 | { |
a88a69c9 | 904 | if (c == ECHO_OP_START) { |
57c94121 JS |
905 | add_echo_byte(ECHO_OP_START, ldata); |
906 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 907 | } else { |
57c94121 | 908 | add_echo_byte(c, ldata); |
a88a69c9 | 909 | } |
a88a69c9 | 910 | } |
1da177e4 | 911 | |
1da177e4 | 912 | /** |
a88a69c9 | 913 | * echo_char - echo a character |
1da177e4 LT |
914 | * @c: unicode byte to echo |
915 | * @tty: terminal device | |
916 | * | |
4edf1827 | 917 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 918 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 919 | * |
62b26358 JP |
920 | * This variant tags control characters to be echoed as "^X" |
921 | * (where X is the letter representing the control char). | |
1da177e4 LT |
922 | */ |
923 | ||
924 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
925 | { | |
bddc7152 JS |
926 | struct n_tty_data *ldata = tty->disc_data; |
927 | ||
a88a69c9 | 928 | if (c == ECHO_OP_START) { |
57c94121 JS |
929 | add_echo_byte(ECHO_OP_START, ldata); |
930 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 931 | } else { |
62b26358 | 932 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
933 | add_echo_byte(ECHO_OP_START, ldata); |
934 | add_echo_byte(c, ldata); | |
a88a69c9 | 935 | } |
1da177e4 LT |
936 | } |
937 | ||
17b82060 | 938 | /** |
a88a69c9 | 939 | * finish_erasing - complete erase |
57c94121 | 940 | * @ldata: n_tty data |
17b82060 | 941 | */ |
a88a69c9 | 942 | |
57c94121 | 943 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 944 | { |
53c5ee2c | 945 | if (ldata->erasing) { |
57c94121 | 946 | echo_char_raw('/', ldata); |
53c5ee2c | 947 | ldata->erasing = 0; |
1da177e4 LT |
948 | } |
949 | } | |
950 | ||
951 | /** | |
952 | * eraser - handle erase function | |
953 | * @c: character input | |
954 | * @tty: terminal device | |
955 | * | |
3a4fa0a2 | 956 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
957 | * present in the stream from the driver layer. Handles the complexities |
958 | * of UTF-8 multibyte symbols. | |
17b82060 | 959 | * |
6d76bd26 PH |
960 | * n_tty_receive_buf()/producer path: |
961 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 962 | */ |
4edf1827 | 963 | |
1da177e4 LT |
964 | static void eraser(unsigned char c, struct tty_struct *tty) |
965 | { | |
53c5ee2c | 966 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 967 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
968 | size_t head; |
969 | size_t cnt; | |
970 | int seen_alnums; | |
1da177e4 | 971 | |
ba2e68ac | 972 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 973 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
974 | return; |
975 | } | |
976 | if (c == ERASE_CHAR(tty)) | |
977 | kill_type = ERASE; | |
978 | else if (c == WERASE_CHAR(tty)) | |
979 | kill_type = WERASE; | |
980 | else { | |
981 | if (!L_ECHO(tty)) { | |
ba2e68ac | 982 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
983 | return; |
984 | } | |
985 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 986 | ldata->read_head = ldata->canon_head; |
57c94121 | 987 | finish_erasing(ldata); |
1da177e4 LT |
988 | echo_char(KILL_CHAR(tty), tty); |
989 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
990 | if (L_ECHOK(tty)) | |
57c94121 | 991 | echo_char_raw('\n', ldata); |
1da177e4 LT |
992 | return; |
993 | } | |
994 | kill_type = KILL; | |
995 | } | |
996 | ||
997 | seen_alnums = 0; | |
ba2e68ac JS |
998 | while (ldata->read_head != ldata->canon_head) { |
999 | head = ldata->read_head; | |
1da177e4 LT |
1000 | |
1001 | /* erase a single possibly multibyte character */ | |
1002 | do { | |
bc5a5e3f PH |
1003 | head--; |
1004 | c = read_buf(ldata, head); | |
ba2e68ac | 1005 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1006 | |
1007 | /* do not partially erase */ | |
1008 | if (is_continuation(c, tty)) | |
1009 | break; | |
1010 | ||
1011 | if (kill_type == WERASE) { | |
1012 | /* Equivalent to BSD's ALTWERASE. */ | |
1013 | if (isalnum(c) || c == '_') | |
1014 | seen_alnums++; | |
1015 | else if (seen_alnums) | |
1016 | break; | |
1017 | } | |
bc5a5e3f | 1018 | cnt = ldata->read_head - head; |
ba2e68ac | 1019 | ldata->read_head = head; |
1da177e4 LT |
1020 | if (L_ECHO(tty)) { |
1021 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1022 | if (!ldata->erasing) { |
57c94121 | 1023 | echo_char_raw('\\', ldata); |
53c5ee2c | 1024 | ldata->erasing = 1; |
1da177e4 LT |
1025 | } |
1026 | /* if cnt > 1, output a multi-byte character */ | |
1027 | echo_char(c, tty); | |
1028 | while (--cnt > 0) { | |
bc5a5e3f PH |
1029 | head++; |
1030 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1031 | echo_move_back_col(ldata); |
1da177e4 LT |
1032 | } |
1033 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1034 | echo_char(ERASE_CHAR(tty), tty); | |
1035 | } else if (c == '\t') { | |
a88a69c9 JP |
1036 | unsigned int num_chars = 0; |
1037 | int after_tab = 0; | |
bc5a5e3f | 1038 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1039 | |
1040 | /* | |
1041 | * Count the columns used for characters | |
1042 | * since the start of input or after a | |
1043 | * previous tab. | |
1044 | * This info is used to go back the correct | |
1045 | * number of columns. | |
1046 | */ | |
ba2e68ac | 1047 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1048 | tail--; |
1049 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1050 | if (c == '\t') { |
1051 | after_tab = 1; | |
1052 | break; | |
300a6204 | 1053 | } else if (iscntrl(c)) { |
1da177e4 | 1054 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1055 | num_chars += 2; |
1056 | } else if (!is_continuation(c, tty)) { | |
1057 | num_chars++; | |
1058 | } | |
1da177e4 | 1059 | } |
57c94121 | 1060 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1061 | } else { |
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 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1068 | echo_char_raw('\b', ldata); |
1069 | echo_char_raw(' ', ldata); | |
1070 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1071 | } |
1072 | } | |
1073 | } | |
1074 | if (kill_type == ERASE) | |
1075 | break; | |
1076 | } | |
ba2e68ac | 1077 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1078 | finish_erasing(ldata); |
1da177e4 LT |
1079 | } |
1080 | ||
1081 | /** | |
1082 | * isig - handle the ISIG optio | |
1083 | * @sig: signal | |
1084 | * @tty: terminal | |
1da177e4 | 1085 | * |
8c985d18 PH |
1086 | * Called when a signal is being sent due to terminal input. |
1087 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1088 | * |
d2b6f447 PH |
1089 | * Performs input and output flush if !NOFLSH. In this context, the echo |
1090 | * buffer is 'output'. The signal is processed first to alert any current | |
1091 | * readers or writers to discontinue and exit their i/o loops. | |
1092 | * | |
8c985d18 | 1093 | * Locking: ctrl_lock |
1da177e4 | 1094 | */ |
4edf1827 | 1095 | |
3b19e032 | 1096 | static void __isig(int sig, struct tty_struct *tty) |
1da177e4 | 1097 | { |
8c985d18 PH |
1098 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1099 | if (tty_pgrp) { | |
1100 | kill_pgrp(tty_pgrp, sig, 1); | |
1101 | put_pid(tty_pgrp); | |
1da177e4 | 1102 | } |
3b19e032 | 1103 | } |
d2b6f447 | 1104 | |
3b19e032 PH |
1105 | static void isig(int sig, struct tty_struct *tty) |
1106 | { | |
1107 | struct n_tty_data *ldata = tty->disc_data; | |
1108 | ||
1109 | if (L_NOFLSH(tty)) { | |
1110 | /* signal only */ | |
1111 | __isig(sig, tty); | |
1112 | ||
1113 | } else { /* signal and flush */ | |
d2b6f447 PH |
1114 | up_read(&tty->termios_rwsem); |
1115 | down_write(&tty->termios_rwsem); | |
1116 | ||
3b19e032 PH |
1117 | __isig(sig, tty); |
1118 | ||
d2b6f447 PH |
1119 | /* clear echo buffer */ |
1120 | mutex_lock(&ldata->output_lock); | |
1121 | ldata->echo_head = ldata->echo_tail = 0; | |
1122 | ldata->echo_mark = ldata->echo_commit = 0; | |
1123 | mutex_unlock(&ldata->output_lock); | |
1124 | ||
1125 | /* clear output buffer */ | |
1126 | tty_driver_flush_buffer(tty); | |
1127 | ||
1128 | /* clear input buffer */ | |
1129 | reset_buffer_flags(tty->disc_data); | |
1130 | ||
1131 | /* notify pty master of flush */ | |
1132 | if (tty->link) | |
1133 | n_tty_packet_mode_flush(tty); | |
1134 | ||
1135 | up_write(&tty->termios_rwsem); | |
1136 | down_read(&tty->termios_rwsem); | |
1137 | } | |
1da177e4 LT |
1138 | } |
1139 | ||
1140 | /** | |
1141 | * n_tty_receive_break - handle break | |
1142 | * @tty: terminal | |
1143 | * | |
1144 | * An RS232 break event has been hit in the incoming bitstream. This | |
1145 | * can cause a variety of events depending upon the termios settings. | |
1146 | * | |
6d76bd26 PH |
1147 | * n_tty_receive_buf()/producer path: |
1148 | * caller holds non-exclusive termios_rwsem | |
6d76bd26 PH |
1149 | * |
1150 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1151 | */ |
4edf1827 | 1152 | |
4b293492 | 1153 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1154 | { |
57c94121 JS |
1155 | struct n_tty_data *ldata = tty->disc_data; |
1156 | ||
1da177e4 LT |
1157 | if (I_IGNBRK(tty)) |
1158 | return; | |
1159 | if (I_BRKINT(tty)) { | |
8c985d18 | 1160 | isig(SIGINT, tty); |
1da177e4 LT |
1161 | return; |
1162 | } | |
1163 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1164 | put_tty_queue('\377', ldata); |
1165 | put_tty_queue('\0', ldata); | |
1da177e4 | 1166 | } |
57c94121 | 1167 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1168 | } |
1169 | ||
1170 | /** | |
1171 | * n_tty_receive_overrun - handle overrun reporting | |
1172 | * @tty: terminal | |
1173 | * | |
1174 | * Data arrived faster than we could process it. While the tty | |
1175 | * driver has flagged this the bits that were missed are gone | |
1176 | * forever. | |
1177 | * | |
1178 | * Called from the receive_buf path so single threaded. Does not | |
1179 | * need locking as num_overrun and overrun_time are function | |
1180 | * private. | |
1181 | */ | |
4edf1827 | 1182 | |
4b293492 | 1183 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1184 | { |
53c5ee2c | 1185 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1186 | |
53c5ee2c JS |
1187 | ldata->num_overrun++; |
1188 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1189 | time_after(ldata->overrun_time, jiffies)) { | |
339f36ba | 1190 | tty_warn(tty, "%d input overrun(s)\n", ldata->num_overrun); |
53c5ee2c JS |
1191 | ldata->overrun_time = jiffies; |
1192 | ldata->num_overrun = 0; | |
1da177e4 LT |
1193 | } |
1194 | } | |
1195 | ||
1196 | /** | |
1197 | * n_tty_receive_parity_error - error notifier | |
1198 | * @tty: terminal device | |
1199 | * @c: character | |
1200 | * | |
1201 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1202 | * the error case if necessary. |
1203 | * | |
1204 | * n_tty_receive_buf()/producer path: | |
1205 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 1206 | */ |
4b293492 | 1207 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1208 | { |
57c94121 JS |
1209 | struct n_tty_data *ldata = tty->disc_data; |
1210 | ||
66528f90 PH |
1211 | if (I_INPCK(tty)) { |
1212 | if (I_IGNPAR(tty)) | |
1213 | return; | |
1214 | if (I_PARMRK(tty)) { | |
1215 | put_tty_queue('\377', ldata); | |
1216 | put_tty_queue('\0', ldata); | |
1217 | put_tty_queue(c, ldata); | |
1218 | } else | |
1219 | put_tty_queue('\0', ldata); | |
1220 | } else | |
57c94121 | 1221 | put_tty_queue(c, ldata); |
1da177e4 LT |
1222 | } |
1223 | ||
b0ac50be PH |
1224 | static void |
1225 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1226 | { | |
d2b6f447 | 1227 | isig(signal, tty); |
b0ac50be PH |
1228 | if (I_IXON(tty)) |
1229 | start_tty(tty); | |
1230 | if (L_ECHO(tty)) { | |
1231 | echo_char(c, tty); | |
1232 | commit_echoes(tty); | |
e2613be5 PH |
1233 | } else |
1234 | process_echoes(tty); | |
b0ac50be PH |
1235 | return; |
1236 | } | |
1237 | ||
1da177e4 LT |
1238 | /** |
1239 | * n_tty_receive_char - perform processing | |
1240 | * @tty: terminal device | |
1241 | * @c: character | |
1242 | * | |
1243 | * Process an individual character of input received from the driver. | |
4edf1827 | 1244 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1245 | * driver above. |
6d76bd26 PH |
1246 | * |
1247 | * n_tty_receive_buf()/producer path: | |
1248 | * caller holds non-exclusive termios_rwsem | |
1249 | * publishes canon_head if canonical mode is active | |
e60d27c4 PH |
1250 | * |
1251 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1252 | */ |
1253 | ||
e60d27c4 | 1254 | static int |
4b1f79c2 | 1255 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1256 | { |
53c5ee2c | 1257 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1258 | |
1da177e4 LT |
1259 | if (I_IXON(tty)) { |
1260 | if (c == START_CHAR(tty)) { | |
1261 | start_tty(tty); | |
e2613be5 | 1262 | process_echoes(tty); |
e60d27c4 | 1263 | return 0; |
1da177e4 LT |
1264 | } |
1265 | if (c == STOP_CHAR(tty)) { | |
1266 | stop_tty(tty); | |
e60d27c4 | 1267 | return 0; |
1da177e4 LT |
1268 | } |
1269 | } | |
575537b3 | 1270 | |
1da177e4 | 1271 | if (L_ISIG(tty)) { |
b0ac50be PH |
1272 | if (c == INTR_CHAR(tty)) { |
1273 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1274 | return 0; |
b0ac50be PH |
1275 | } else if (c == QUIT_CHAR(tty)) { |
1276 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1277 | return 0; |
b0ac50be PH |
1278 | } else if (c == SUSP_CHAR(tty)) { |
1279 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1280 | return 0; |
1da177e4 LT |
1281 | } |
1282 | } | |
575537b3 | 1283 | |
855df3c0 PH |
1284 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1285 | start_tty(tty); | |
1286 | process_echoes(tty); | |
1287 | } | |
1288 | ||
575537b3 JP |
1289 | if (c == '\r') { |
1290 | if (I_IGNCR(tty)) | |
e60d27c4 | 1291 | return 0; |
575537b3 JP |
1292 | if (I_ICRNL(tty)) |
1293 | c = '\n'; | |
1294 | } else if (c == '\n' && I_INLCR(tty)) | |
1295 | c = '\r'; | |
1296 | ||
53c5ee2c | 1297 | if (ldata->icanon) { |
1da177e4 LT |
1298 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1299 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1300 | eraser(c, tty); | |
17bd7907 | 1301 | commit_echoes(tty); |
e60d27c4 | 1302 | return 0; |
1da177e4 LT |
1303 | } |
1304 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1305 | ldata->lnext = 1; |
1da177e4 | 1306 | if (L_ECHO(tty)) { |
57c94121 | 1307 | finish_erasing(ldata); |
1da177e4 | 1308 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1309 | echo_char_raw('^', ldata); |
1310 | echo_char_raw('\b', ldata); | |
17bd7907 | 1311 | commit_echoes(tty); |
1da177e4 LT |
1312 | } |
1313 | } | |
e60d27c4 | 1314 | return 1; |
1da177e4 | 1315 | } |
e60d27c4 | 1316 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1317 | size_t tail = ldata->canon_head; |
1da177e4 | 1318 | |
57c94121 | 1319 | finish_erasing(ldata); |
1da177e4 | 1320 | echo_char(c, tty); |
57c94121 | 1321 | echo_char_raw('\n', ldata); |
ba2e68ac | 1322 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1323 | echo_char(read_buf(ldata, tail), tty); |
1324 | tail++; | |
1da177e4 | 1325 | } |
17bd7907 | 1326 | commit_echoes(tty); |
e60d27c4 | 1327 | return 0; |
1da177e4 LT |
1328 | } |
1329 | if (c == '\n') { | |
acc71bba | 1330 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1331 | echo_char_raw('\n', ldata); |
17bd7907 | 1332 | commit_echoes(tty); |
1da177e4 LT |
1333 | } |
1334 | goto handle_newline; | |
1335 | } | |
1336 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1337 | c = __DISABLED_CHAR; |
1338 | goto handle_newline; | |
1339 | } | |
1340 | if ((c == EOL_CHAR(tty)) || | |
1341 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1342 | /* | |
1343 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1344 | */ | |
1345 | if (L_ECHO(tty)) { | |
1da177e4 | 1346 | /* Record the column of first canon char. */ |
ba2e68ac | 1347 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1348 | echo_set_canon_col(ldata); |
1da177e4 | 1349 | echo_char(c, tty); |
17bd7907 | 1350 | commit_echoes(tty); |
1da177e4 LT |
1351 | } |
1352 | /* | |
1353 | * XXX does PARMRK doubling happen for | |
1354 | * EOL_CHAR and EOL2_CHAR? | |
1355 | */ | |
001ba923 | 1356 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
57c94121 | 1357 | put_tty_queue(c, ldata); |
1da177e4 | 1358 | |
4edf1827 | 1359 | handle_newline: |
bc5a5e3f | 1360 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1361 | put_tty_queue(c, ldata); |
70aca71f | 1362 | smp_store_release(&ldata->canon_head, ldata->read_head); |
1da177e4 | 1363 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
e81107d4 | 1364 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
e60d27c4 | 1365 | return 0; |
1da177e4 LT |
1366 | } |
1367 | } | |
4edf1827 | 1368 | |
acc71bba | 1369 | if (L_ECHO(tty)) { |
57c94121 | 1370 | finish_erasing(ldata); |
1da177e4 | 1371 | if (c == '\n') |
57c94121 | 1372 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1373 | else { |
1374 | /* Record the column of first canon char. */ | |
ba2e68ac | 1375 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1376 | echo_set_canon_col(ldata); |
1da177e4 LT |
1377 | echo_char(c, tty); |
1378 | } | |
17bd7907 | 1379 | commit_echoes(tty); |
1da177e4 LT |
1380 | } |
1381 | ||
001ba923 PH |
1382 | /* PARMRK doubling check */ |
1383 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
57c94121 | 1384 | put_tty_queue(c, ldata); |
1da177e4 | 1385 | |
57c94121 | 1386 | put_tty_queue(c, ldata); |
e60d27c4 | 1387 | return 0; |
4edf1827 | 1388 | } |
1da177e4 | 1389 | |
e60d27c4 PH |
1390 | static inline void |
1391 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1392 | { |
1393 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1394 | |
e60d27c4 PH |
1395 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1396 | start_tty(tty); | |
1397 | process_echoes(tty); | |
1398 | } | |
1399 | if (L_ECHO(tty)) { | |
1400 | finish_erasing(ldata); | |
1401 | /* Record the column of first canon char. */ | |
1402 | if (ldata->canon_head == ldata->read_head) | |
1403 | echo_set_canon_col(ldata); | |
1404 | echo_char(c, tty); | |
1405 | commit_echoes(tty); | |
4b1f79c2 | 1406 | } |
001ba923 PH |
1407 | /* PARMRK doubling check */ |
1408 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
e60d27c4 PH |
1409 | put_tty_queue(c, ldata); |
1410 | put_tty_queue(c, ldata); | |
1411 | } | |
4b1f79c2 | 1412 | |
eb3e4668 | 1413 | static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
e60d27c4 PH |
1414 | { |
1415 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1416 | } |
1417 | ||
7de971b0 PH |
1418 | static inline void |
1419 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1420 | { | |
1421 | struct n_tty_data *ldata = tty->disc_data; | |
1422 | ||
e60d27c4 PH |
1423 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1424 | start_tty(tty); | |
1425 | process_echoes(tty); | |
7de971b0 | 1426 | } |
e60d27c4 PH |
1427 | if (L_ECHO(tty)) { |
1428 | finish_erasing(ldata); | |
1429 | /* Record the column of first canon char. */ | |
1430 | if (ldata->canon_head == ldata->read_head) | |
1431 | echo_set_canon_col(ldata); | |
1432 | echo_char(c, tty); | |
1433 | commit_echoes(tty); | |
1434 | } | |
1435 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1436 | } |
1437 | ||
8dc4b25d | 1438 | static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) |
ad0cc7ba PH |
1439 | { |
1440 | if (I_ISTRIP(tty)) | |
1441 | c &= 0x7f; | |
1442 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1443 | c = tolower(c); | |
1444 | ||
1445 | if (I_IXON(tty)) { | |
1446 | if (c == STOP_CHAR(tty)) | |
1447 | stop_tty(tty); | |
1448 | else if (c == START_CHAR(tty) || | |
1449 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1450 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1451 | c != SUSP_CHAR(tty))) { | |
1452 | start_tty(tty); | |
1453 | process_echoes(tty); | |
1454 | } | |
1455 | } | |
1456 | } | |
1457 | ||
d2f8d7ab PH |
1458 | static void |
1459 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1460 | { | |
d2f8d7ab PH |
1461 | switch (flag) { |
1462 | case TTY_BREAK: | |
1463 | n_tty_receive_break(tty); | |
1464 | break; | |
1465 | case TTY_PARITY: | |
1466 | case TTY_FRAME: | |
1467 | n_tty_receive_parity_error(tty, c); | |
1468 | break; | |
1469 | case TTY_OVERRUN: | |
1470 | n_tty_receive_overrun(tty); | |
1471 | break; | |
1472 | default: | |
339f36ba | 1473 | tty_err(tty, "unknown flag %d\n", flag); |
d2f8d7ab PH |
1474 | break; |
1475 | } | |
1476 | } | |
1477 | ||
e60d27c4 PH |
1478 | static void |
1479 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1480 | { | |
1481 | struct n_tty_data *ldata = tty->disc_data; | |
1482 | ||
1483 | ldata->lnext = 0; | |
1484 | if (likely(flag == TTY_NORMAL)) { | |
1485 | if (I_ISTRIP(tty)) | |
1486 | c &= 0x7f; | |
1487 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1488 | c = tolower(c); | |
1489 | n_tty_receive_char(tty, c); | |
1490 | } else | |
1491 | n_tty_receive_char_flagged(tty, c, flag); | |
1492 | } | |
1493 | ||
4a23a4df PH |
1494 | static void |
1495 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1496 | char *fp, int count) | |
1497 | { | |
1498 | struct n_tty_data *ldata = tty->disc_data; | |
1499 | size_t n, head; | |
1500 | ||
1501 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1502 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1503 | memcpy(read_buf_addr(ldata, head), cp, n); |
1504 | ldata->read_head += n; | |
1505 | cp += n; | |
1506 | count -= n; | |
1507 | ||
1508 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1509 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1510 | memcpy(read_buf_addr(ldata, head), cp, n); |
1511 | ldata->read_head += n; | |
1512 | } | |
1513 | ||
554117bd PH |
1514 | static void |
1515 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1516 | char *fp, int count) | |
1517 | { | |
1518 | struct n_tty_data *ldata = tty->disc_data; | |
1519 | char flag = TTY_NORMAL; | |
1520 | ||
1521 | while (count--) { | |
1522 | if (fp) | |
1523 | flag = *fp++; | |
1524 | if (likely(flag == TTY_NORMAL)) | |
1525 | put_tty_queue(*cp++, ldata); | |
1526 | else | |
1527 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1528 | } | |
1529 | } | |
1530 | ||
ad0cc7ba PH |
1531 | static void |
1532 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1533 | char *fp, int count) | |
1534 | { | |
1535 | char flag = TTY_NORMAL; | |
1536 | ||
1537 | while (count--) { | |
1538 | if (fp) | |
1539 | flag = *fp++; | |
1540 | if (likely(flag == TTY_NORMAL)) | |
1541 | n_tty_receive_char_closing(tty, *cp++); | |
1542 | else | |
1543 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1544 | } | |
1545 | } | |
1546 | ||
7d88d637 PH |
1547 | static void |
1548 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1549 | char *fp, int count) |
1550 | { | |
1551 | struct n_tty_data *ldata = tty->disc_data; | |
1552 | char flag = TTY_NORMAL; | |
1553 | ||
1554 | while (count--) { | |
1555 | if (fp) | |
1556 | flag = *fp++; | |
1557 | if (likely(flag == TTY_NORMAL)) { | |
1558 | unsigned char c = *cp++; | |
1559 | ||
1560 | if (I_ISTRIP(tty)) | |
1561 | c &= 0x7f; | |
1562 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1563 | c = tolower(c); | |
1564 | if (L_EXTPROC(tty)) { | |
1565 | put_tty_queue(c, ldata); | |
1566 | continue; | |
1567 | } | |
e60d27c4 PH |
1568 | if (!test_bit(c, ldata->char_map)) |
1569 | n_tty_receive_char_inline(tty, c); | |
1570 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1571 | if (fp) | |
1572 | flag = *fp++; | |
1573 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1574 | count--; | |
1575 | } | |
6baad008 PH |
1576 | } else |
1577 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1578 | } | |
1579 | } | |
1580 | ||
1581 | static void | |
1582 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1583 | char *fp, int count) | |
7d88d637 | 1584 | { |
e60d27c4 | 1585 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1586 | char flag = TTY_NORMAL; |
1587 | ||
1588 | while (count--) { | |
1589 | if (fp) | |
1590 | flag = *fp++; | |
e60d27c4 PH |
1591 | if (likely(flag == TTY_NORMAL)) { |
1592 | unsigned char c = *cp++; | |
1593 | ||
1594 | if (!test_bit(c, ldata->char_map)) | |
1595 | n_tty_receive_char_fast(tty, c); | |
1596 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1597 | if (fp) | |
1598 | flag = *fp++; | |
1599 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1600 | count--; | |
1601 | } | |
1602 | } else | |
7d88d637 PH |
1603 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1604 | } | |
1605 | } | |
1606 | ||
24a89d1c PH |
1607 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1608 | char *fp, int count) | |
1da177e4 | 1609 | { |
53c5ee2c | 1610 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1611 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1612 | |
4a23a4df PH |
1613 | if (ldata->real_raw) |
1614 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1615 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1616 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1617 | else if (tty->closing && !L_EXTPROC(tty)) |
1618 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1619 | else { |
e60d27c4 PH |
1620 | if (ldata->lnext) { |
1621 | char flag = TTY_NORMAL; | |
1622 | ||
1623 | if (fp) | |
1624 | flag = *fp++; | |
1625 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1626 | count--; | |
1627 | } | |
1628 | ||
7de971b0 | 1629 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1630 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1631 | else | |
1632 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1633 | |
1634 | flush_echoes(tty); | |
f34d7a5b AC |
1635 | if (tty->ops->flush_chars) |
1636 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1637 | } |
1638 | ||
70aca71f PH |
1639 | if (ldata->icanon && !L_EXTPROC(tty)) |
1640 | return; | |
1641 | ||
1642 | /* publish read_head to consumer */ | |
1643 | smp_store_release(&ldata->commit_head, ldata->read_head); | |
1644 | ||
1645 | if ((read_cnt(ldata) >= ldata->minimum_to_wake) || L_EXTPROC(tty)) { | |
1da177e4 | 1646 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
e81107d4 | 1647 | wake_up_interruptible_poll(&tty->read_wait, POLLIN); |
1da177e4 | 1648 | } |
1da177e4 LT |
1649 | } |
1650 | ||
fb5ef9e7 PH |
1651 | /** |
1652 | * n_tty_receive_buf_common - process input | |
1653 | * @tty: device to receive input | |
1654 | * @cp: input chars | |
1655 | * @fp: flags for each char (if NULL, all chars are TTY_NORMAL) | |
1656 | * @count: number of input chars in @cp | |
1657 | * | |
1658 | * Called by the terminal driver when a block of characters has | |
1659 | * been received. This function must be called from soft contexts | |
1660 | * not from interrupt context. The driver is responsible for making | |
1661 | * calls one at a time and in order (or using flush_to_ldisc) | |
1662 | * | |
1663 | * Returns the # of input chars from @cp which were processed. | |
1664 | * | |
1665 | * In canonical mode, the maximum line length is 4096 chars (including | |
1666 | * the line termination char); lines longer than 4096 chars are | |
1667 | * truncated. After 4095 chars, input data is still processed but | |
1668 | * not stored. Overflow processing ensures the tty can always | |
1669 | * receive more input until at least one line can be read. | |
1670 | * | |
1671 | * In non-canonical mode, the read buffer will only accept 4095 chars; | |
1672 | * this provides the necessary space for a newline char if the input | |
1673 | * mode is switched to canonical. | |
1674 | * | |
1675 | * Note it is possible for the read buffer to _contain_ 4096 chars | |
1676 | * in non-canonical mode: the read buffer could already contain the | |
1677 | * maximum canon line of 4096 chars when the mode is switched to | |
1678 | * non-canonical. | |
1679 | * | |
1680 | * n_tty_receive_buf()/producer path: | |
1681 | * claims non-exclusive termios_rwsem | |
1682 | * publishes commit_head or canon_head | |
1683 | */ | |
5c32d123 PH |
1684 | static int |
1685 | n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, | |
1686 | char *fp, int count, int flow) | |
24a89d1c PH |
1687 | { |
1688 | struct n_tty_data *ldata = tty->disc_data; | |
fb5ef9e7 | 1689 | int room, n, rcvd = 0, overflow; |
24a89d1c | 1690 | |
9356b535 PH |
1691 | down_read(&tty->termios_rwsem); |
1692 | ||
19e2ad6a | 1693 | while (1) { |
70aca71f | 1694 | /* |
06c49f9f PH |
1695 | * When PARMRK is set, each input char may take up to 3 chars |
1696 | * in the read buf; reduce the buffer space avail by 3x | |
70aca71f PH |
1697 | * |
1698 | * If we are doing input canonicalization, and there are no | |
1699 | * pending newlines, let characters through without limit, so | |
1700 | * that erase characters will be handled. Other excess | |
1701 | * characters will be beeped. | |
1702 | * | |
1703 | * paired with store in *_copy_from_read_buf() -- guarantees | |
1704 | * the consumer has loaded the data in read_buf up to the new | |
1705 | * read_tail (so this producer will not overwrite unread data) | |
1706 | */ | |
1707 | size_t tail = smp_load_acquire(&ldata->read_tail); | |
70aca71f | 1708 | |
fb5ef9e7 | 1709 | room = N_TTY_BUF_SIZE - (ldata->read_head - tail); |
70aca71f | 1710 | if (I_PARMRK(tty)) |
fb5ef9e7 PH |
1711 | room = (room + 2) / 3; |
1712 | room--; | |
1713 | if (room <= 0) { | |
1714 | overflow = ldata->icanon && ldata->canon_head == tail; | |
1715 | if (overflow && room < 0) | |
1716 | ldata->read_head--; | |
1717 | room = overflow; | |
1718 | ldata->no_room = flow && !room; | |
1719 | } else | |
1720 | overflow = 0; | |
70aca71f | 1721 | |
19e2ad6a | 1722 | n = min(count, room); |
fb5ef9e7 | 1723 | if (!n) |
19e2ad6a | 1724 | break; |
fb5ef9e7 PH |
1725 | |
1726 | /* ignore parity errors if handling overflow */ | |
1727 | if (!overflow || !fp || *fp != TTY_PARITY) | |
1728 | __receive_buf(tty, cp, fp, n); | |
1729 | ||
19e2ad6a PH |
1730 | cp += n; |
1731 | if (fp) | |
1732 | fp += n; | |
1733 | count -= n; | |
1734 | rcvd += n; | |
4a23a4df | 1735 | } |
24a89d1c | 1736 | |
19e2ad6a | 1737 | tty->receive_room = room; |
fb5ef9e7 PH |
1738 | |
1739 | /* Unthrottle if handling overflow on pty */ | |
1740 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { | |
1741 | if (overflow) { | |
1742 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1743 | tty_unthrottle_safe(tty); | |
1744 | __tty_set_flow_change(tty, 0); | |
1745 | } | |
1746 | } else | |
1747 | n_tty_check_throttle(tty); | |
1748 | ||
9356b535 PH |
1749 | up_read(&tty->termios_rwsem); |
1750 | ||
19e2ad6a | 1751 | return rcvd; |
24a89d1c PH |
1752 | } |
1753 | ||
5c32d123 PH |
1754 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1755 | char *fp, int count) | |
1756 | { | |
1757 | n_tty_receive_buf_common(tty, cp, fp, count, 0); | |
1758 | } | |
1759 | ||
1760 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1761 | char *fp, int count) | |
1762 | { | |
1763 | return n_tty_receive_buf_common(tty, cp, fp, count, 1); | |
1764 | } | |
1765 | ||
1da177e4 LT |
1766 | int is_ignored(int sig) |
1767 | { | |
1768 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1769 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1770 | } |
1771 | ||
1772 | /** | |
1773 | * n_tty_set_termios - termios data changed | |
1774 | * @tty: terminal | |
1775 | * @old: previous data | |
1776 | * | |
1777 | * Called by the tty layer when the user changes termios flags so | |
1778 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1779 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1780 | * guaranteed that this function will not be re-entered or in progress |
1781 | * when the ldisc is closed. | |
17b82060 | 1782 | * |
6a1c0680 | 1783 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1784 | */ |
4edf1827 AC |
1785 | |
1786 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1787 | { |
53c5ee2c | 1788 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1789 | |
c786f74e | 1790 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { |
3fe780b3 | 1791 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1792 | ldata->line_start = ldata->read_tail; |
1793 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1794 | ldata->canon_head = ldata->read_tail; | |
1795 | ldata->push = 0; | |
1796 | } else { | |
1797 | set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), | |
1798 | ldata->read_flags); | |
1799 | ldata->canon_head = ldata->read_head; | |
1800 | ldata->push = 1; | |
1801 | } | |
70aca71f | 1802 | ldata->commit_head = ldata->read_head; |
53c5ee2c | 1803 | ldata->erasing = 0; |
6f9b028a | 1804 | ldata->lnext = 0; |
47afa7a5 AC |
1805 | } |
1806 | ||
53c5ee2c | 1807 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1808 | |
1da177e4 LT |
1809 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1810 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1811 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1812 | I_PARMRK(tty)) { | |
1bb9d562 | 1813 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1814 | |
1815 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1816 | set_bit('\r', ldata->char_map); |
1da177e4 | 1817 | if (I_INLCR(tty)) |
1bb9d562 | 1818 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1819 | |
1820 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1821 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1822 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1823 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1824 | set_bit('\n', ldata->char_map); | |
1825 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1826 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1827 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1828 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1829 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1830 | if (L_ECHO(tty)) |
1831 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1832 | ldata->char_map); |
1da177e4 LT |
1833 | } |
1834 | } | |
1835 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1836 | set_bit(START_CHAR(tty), ldata->char_map); |
1837 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1838 | } |
1839 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1840 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1841 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1842 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1843 | } |
1bb9d562 | 1844 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1845 | ldata->raw = 0; |
1846 | ldata->real_raw = 0; | |
1da177e4 | 1847 | } else { |
53c5ee2c | 1848 | ldata->raw = 1; |
1da177e4 LT |
1849 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1850 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1851 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1852 | ldata->real_raw = 1; |
1da177e4 | 1853 | else |
53c5ee2c | 1854 | ldata->real_raw = 0; |
1da177e4 | 1855 | } |
dab73b4e WY |
1856 | /* |
1857 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1858 | * been stopped by STOP_CHAR(tty) before it. | |
1859 | */ | |
e2613be5 | 1860 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { |
dab73b4e | 1861 | start_tty(tty); |
e2613be5 PH |
1862 | process_echoes(tty); |
1863 | } | |
dab73b4e | 1864 | |
f34d7a5b | 1865 | /* The termios change make the tty ready for I/O */ |
e81107d4 KT |
1866 | wake_up_interruptible(&tty->write_wait); |
1867 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1868 | } |
1869 | ||
1870 | /** | |
1871 | * n_tty_close - close the ldisc for this tty | |
1872 | * @tty: device | |
1873 | * | |
4edf1827 AC |
1874 | * Called from the terminal layer when this line discipline is |
1875 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1876 | * discipline change. The function will not be called while other |
1877 | * ldisc methods are in progress. | |
1878 | */ | |
4edf1827 | 1879 | |
1da177e4 LT |
1880 | static void n_tty_close(struct tty_struct *tty) |
1881 | { | |
70ece7a7 JS |
1882 | struct n_tty_data *ldata = tty->disc_data; |
1883 | ||
79901317 PH |
1884 | if (tty->link) |
1885 | n_tty_packet_mode_flush(tty); | |
1886 | ||
20bafb3d | 1887 | vfree(ldata); |
70ece7a7 | 1888 | tty->disc_data = NULL; |
1da177e4 LT |
1889 | } |
1890 | ||
1891 | /** | |
1892 | * n_tty_open - open an ldisc | |
1893 | * @tty: terminal to open | |
1894 | * | |
4edf1827 | 1895 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1896 | * terminal device. Can sleep. Called serialized so that no |
1897 | * other events will occur in parallel. No further open will occur | |
1898 | * until a close. | |
1899 | */ | |
1900 | ||
1901 | static int n_tty_open(struct tty_struct *tty) | |
1902 | { | |
70ece7a7 JS |
1903 | struct n_tty_data *ldata; |
1904 | ||
20bafb3d PH |
1905 | /* Currently a malloc failure here can panic */ |
1906 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1907 | if (!ldata) |
1908 | goto err; | |
1909 | ||
53c5ee2c | 1910 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1911 | mutex_init(&ldata->atomic_read_lock); |
1912 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1913 | |
70ece7a7 | 1914 | tty->disc_data = ldata; |
b66f4fa5 | 1915 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1916 | ldata->column = 0; |
20bafb3d | 1917 | ldata->canon_column = 0; |
f6c8dbe6 | 1918 | ldata->minimum_to_wake = 1; |
20bafb3d PH |
1919 | ldata->num_overrun = 0; |
1920 | ldata->no_room = 0; | |
1921 | ldata->lnext = 0; | |
1da177e4 | 1922 | tty->closing = 0; |
b66f4fa5 PH |
1923 | /* indicate buffer work may resume */ |
1924 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1925 | n_tty_set_termios(tty, NULL); | |
1926 | tty_unthrottle(tty); | |
70ece7a7 | 1927 | |
1da177e4 | 1928 | return 0; |
70ece7a7 | 1929 | err: |
b91939f5 | 1930 | return -ENOMEM; |
1da177e4 LT |
1931 | } |
1932 | ||
eafbe67f | 1933 | static inline int input_available_p(struct tty_struct *tty, int poll) |
1da177e4 | 1934 | { |
53c5ee2c | 1935 | struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1936 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1937 | |
25e8d0ed PH |
1938 | if (ldata->icanon && !L_EXTPROC(tty)) |
1939 | return ldata->canon_head != ldata->read_tail; | |
1940 | else | |
70aca71f | 1941 | return ldata->commit_head - ldata->read_tail >= amt; |
1da177e4 LT |
1942 | } |
1943 | ||
1a48632f PH |
1944 | static inline int check_other_done(struct tty_struct *tty) |
1945 | { | |
1946 | int done = test_bit(TTY_OTHER_DONE, &tty->flags); | |
1947 | if (done) { | |
1948 | /* paired with cmpxchg() in check_other_closed(); ensures | |
1949 | * read buffer head index is not stale | |
1950 | */ | |
1951 | smp_mb__after_atomic(); | |
1952 | } | |
1953 | return done; | |
1954 | } | |
1955 | ||
1da177e4 | 1956 | /** |
bbd20759 | 1957 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1958 | * @tty: terminal device |
1959 | * @b: user data | |
1960 | * @nr: size of data | |
1961 | * | |
11a96d18 | 1962 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1963 | * ICANON is off; it copies characters straight from the tty queue to |
1964 | * user space directly. It can be profitably called twice; once to | |
1965 | * drain the space from the tail pointer to the (physical) end of the | |
1966 | * buffer, and once to drain the space from the (physical) beginning of | |
1967 | * the buffer to head pointer. | |
1968 | * | |
bddc7152 | 1969 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1970 | * |
6d76bd26 PH |
1971 | * n_tty_read()/consumer path: |
1972 | * caller holds non-exclusive termios_rwsem | |
1973 | * read_tail published | |
1da177e4 | 1974 | */ |
4edf1827 | 1975 | |
33f0f88f | 1976 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1977 | unsigned char __user **b, |
1978 | size_t *nr) | |
1979 | ||
1980 | { | |
53c5ee2c | 1981 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1982 | int retval; |
1983 | size_t n; | |
3fa10cc8 | 1984 | bool is_eof; |
70aca71f | 1985 | size_t head = smp_load_acquire(&ldata->commit_head); |
bc5a5e3f | 1986 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1987 | |
1988 | retval = 0; | |
70aca71f | 1989 | n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail); |
1da177e4 | 1990 | n = min(*nr, n); |
1da177e4 | 1991 | if (n) { |
e661cf70 PH |
1992 | const unsigned char *from = read_buf_addr(ldata, tail); |
1993 | retval = copy_to_user(*b, from, n); | |
1da177e4 | 1994 | n -= retval; |
e661cf70 PH |
1995 | is_eof = n == 1 && *from == EOF_CHAR(tty); |
1996 | tty_audit_add_data(tty, from, n, ldata->icanon); | |
70aca71f | 1997 | smp_store_release(&ldata->read_tail, ldata->read_tail + n); |
26df6d13 | 1998 | /* Turn single EOF into zero-length read */ |
70aca71f PH |
1999 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && |
2000 | (head == ldata->read_tail)) | |
3fa10cc8 | 2001 | n = 0; |
1da177e4 LT |
2002 | *b += n; |
2003 | *nr -= n; | |
2004 | } | |
2005 | return retval; | |
2006 | } | |
2007 | ||
88bb0de3 | 2008 | /** |
32f13521 | 2009 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
2010 | * @tty: terminal device |
2011 | * @b: user data | |
2012 | * @nr: size of data | |
2013 | * | |
2014 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
2015 | * it copies one line of input up to and including the line-delimiting |
2016 | * character into the user-space buffer. | |
88bb0de3 | 2017 | * |
4d0ed182 PH |
2018 | * NB: When termios is changed from non-canonical to canonical mode and |
2019 | * the read buffer contains data, n_tty_set_termios() simulates an EOF | |
2020 | * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. | |
2021 | * This causes data already processed as input to be immediately available | |
2022 | * as input although a newline has not been received. | |
2023 | * | |
88bb0de3 | 2024 | * Called under the atomic_read_lock mutex |
6d76bd26 PH |
2025 | * |
2026 | * n_tty_read()/consumer path: | |
2027 | * caller holds non-exclusive termios_rwsem | |
2028 | * read_tail published | |
88bb0de3 PH |
2029 | */ |
2030 | ||
32f13521 PH |
2031 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
2032 | unsigned char __user **b, | |
2033 | size_t *nr) | |
88bb0de3 PH |
2034 | { |
2035 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 2036 | size_t n, size, more, c; |
bc5a5e3f PH |
2037 | size_t eol; |
2038 | size_t tail; | |
2039 | int ret, found = 0; | |
88bb0de3 PH |
2040 | |
2041 | /* N.B. avoid overrun if nr == 0 */ | |
ac8f3bf8 | 2042 | if (!*nr) |
32f13521 | 2043 | return 0; |
88bb0de3 | 2044 | |
ac8f3bf8 PH |
2045 | n = min(*nr + 1, smp_load_acquire(&ldata->canon_head) - ldata->read_tail); |
2046 | ||
bc5a5e3f | 2047 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
2048 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
2049 | ||
bc5a5e3f | 2050 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2051 | __func__, *nr, tail, n, size); |
2052 | ||
2053 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2054 | more = n - (size - tail); | |
2055 | if (eol == N_TTY_BUF_SIZE && more) { | |
2056 | /* scan wrapped without finding set bit */ | |
2057 | eol = find_next_bit(ldata->read_flags, more, 0); | |
b985e9e3 PH |
2058 | found = eol != more; |
2059 | } else | |
2060 | found = eol != size; | |
32f13521 | 2061 | |
c77569d2 | 2062 | n = eol - tail; |
da555db6 MT |
2063 | if (n > N_TTY_BUF_SIZE) |
2064 | n += N_TTY_BUF_SIZE; | |
ac8f3bf8 | 2065 | c = n + found; |
32f13521 | 2066 | |
ac8f3bf8 PH |
2067 | if (!found || read_buf(ldata, eol) != __DISABLED_CHAR) { |
2068 | c = min(*nr, c); | |
2069 | n = c; | |
40d5e090 | 2070 | } |
32f13521 | 2071 | |
679e7c29 PH |
2072 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu tail:%zu more:%zu\n", |
2073 | __func__, eol, found, n, c, tail, more); | |
32f13521 | 2074 | |
679e7c29 | 2075 | ret = tty_copy_to_user(tty, *b, tail, n); |
32f13521 PH |
2076 | if (ret) |
2077 | return -EFAULT; | |
2078 | *b += n; | |
2079 | *nr -= n; | |
2080 | ||
a73d3d69 | 2081 | if (found) |
6d76bd26 | 2082 | clear_bit(eol, ldata->read_flags); |
70aca71f | 2083 | smp_store_release(&ldata->read_tail, ldata->read_tail + c); |
88bb0de3 | 2084 | |
40d5e090 | 2085 | if (found) { |
4d0ed182 PH |
2086 | if (!ldata->push) |
2087 | ldata->line_start = ldata->read_tail; | |
2088 | else | |
2089 | ldata->push = 0; | |
32f13521 | 2090 | tty_audit_push(tty); |
40d5e090 | 2091 | } |
ac8f3bf8 | 2092 | return 0; |
88bb0de3 PH |
2093 | } |
2094 | ||
cc4191dc | 2095 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2096 | size_t, loff_t *); |
1da177e4 LT |
2097 | |
2098 | /** | |
2099 | * job_control - check job control | |
2100 | * @tty: tty | |
2101 | * @file: file handle | |
2102 | * | |
2103 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2104 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2105 | * error code if action should be taken. |
04f378b1 | 2106 | * |
01a5e440 PH |
2107 | * Locking: redirected write test is safe |
2108 | * current->signal->tty check is safe | |
2109 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2110 | */ |
4edf1827 | 2111 | |
1da177e4 LT |
2112 | static int job_control(struct tty_struct *tty, struct file *file) |
2113 | { | |
2114 | /* Job control check -- must be done at start and after | |
2115 | every sleep (POSIX.1 7.1.1.4). */ | |
2116 | /* NOTE: not yet done after every sleep pending a thorough | |
2117 | check of the logic of this change. -- jlc */ | |
2118 | /* don't stop on /dev/console */ | |
2812d9e9 | 2119 | if (file->f_op->write == redirected_tty_write) |
01a5e440 PH |
2120 | return 0; |
2121 | ||
2812d9e9 | 2122 | return __tty_check_change(tty, SIGTTIN); |
1da177e4 | 2123 | } |
4edf1827 | 2124 | |
1da177e4 LT |
2125 | |
2126 | /** | |
11a96d18 | 2127 | * n_tty_read - read function for tty |
1da177e4 LT |
2128 | * @tty: tty device |
2129 | * @file: file object | |
2130 | * @buf: userspace buffer pointer | |
2131 | * @nr: size of I/O | |
2132 | * | |
2133 | * Perform reads for the line discipline. We are guaranteed that the | |
2134 | * line discipline will not be closed under us but we may get multiple | |
2135 | * parallel readers and must handle this ourselves. We may also get | |
2136 | * a hangup. Always called in user context, may sleep. | |
2137 | * | |
2138 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2139 | * |
2140 | * n_tty_read()/consumer path: | |
2141 | * claims non-exclusive termios_rwsem | |
2142 | * publishes read_tail | |
1da177e4 | 2143 | */ |
4edf1827 | 2144 | |
11a96d18 | 2145 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2146 | unsigned char __user *buf, size_t nr) |
2147 | { | |
53c5ee2c | 2148 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 2149 | unsigned char __user *b = buf; |
97d9e28d | 2150 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1a48632f | 2151 | int c, done; |
1da177e4 LT |
2152 | int minimum, time; |
2153 | ssize_t retval = 0; | |
1da177e4 | 2154 | long timeout; |
04f378b1 | 2155 | int packet; |
2c5dc464 | 2156 | size_t tail; |
1da177e4 | 2157 | |
1da177e4 | 2158 | c = job_control(tty, file); |
4edf1827 | 2159 | if (c < 0) |
1da177e4 | 2160 | return c; |
4edf1827 | 2161 | |
aefceaf4 PH |
2162 | /* |
2163 | * Internal serialization of reads. | |
2164 | */ | |
2165 | if (file->f_flags & O_NONBLOCK) { | |
2166 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2167 | return -EAGAIN; | |
2168 | } else { | |
2169 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2170 | return -ERESTARTSYS; | |
2171 | } | |
2172 | ||
9356b535 PH |
2173 | down_read(&tty->termios_rwsem); |
2174 | ||
1da177e4 LT |
2175 | minimum = time = 0; |
2176 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2177 | if (!ldata->icanon) { |
1da177e4 LT |
2178 | minimum = MIN_CHAR(tty); |
2179 | if (minimum) { | |
a6e54319 | 2180 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2181 | if (time) |
f6c8dbe6 | 2182 | ldata->minimum_to_wake = 1; |
1da177e4 | 2183 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
2184 | (ldata->minimum_to_wake > minimum)) |
2185 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 2186 | } else { |
a6e54319 | 2187 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2188 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2189 | } |
2190 | } | |
2191 | ||
04f378b1 | 2192 | packet = tty->packet; |
2c5dc464 | 2193 | tail = ldata->read_tail; |
1da177e4 LT |
2194 | |
2195 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2196 | while (nr) { |
2197 | /* First test for status change. */ | |
04f378b1 | 2198 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2199 | unsigned char cs; |
2200 | if (b != buf) | |
2201 | break; | |
6054c16e | 2202 | spin_lock_irq(&tty->link->ctrl_lock); |
1da177e4 LT |
2203 | cs = tty->link->ctrl_status; |
2204 | tty->link->ctrl_status = 0; | |
6054c16e | 2205 | spin_unlock_irq(&tty->link->ctrl_lock); |
522ed776 | 2206 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2207 | retval = -EFAULT; |
2208 | b--; | |
2209 | break; | |
2210 | } | |
2211 | nr--; | |
2212 | break; | |
2213 | } | |
4edf1827 | 2214 | |
f6c8dbe6 | 2215 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2216 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2217 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2218 | |
1a48632f PH |
2219 | done = check_other_done(tty); |
2220 | ||
1da177e4 | 2221 | if (!input_available_p(tty, 0)) { |
1a48632f | 2222 | if (done) { |
52bce7f8 PH |
2223 | retval = -EIO; |
2224 | break; | |
f8747d4a | 2225 | } |
52bce7f8 PH |
2226 | if (tty_hung_up_p(file)) |
2227 | break; | |
2228 | if (!timeout) | |
2229 | break; | |
2230 | if (file->f_flags & O_NONBLOCK) { | |
2231 | retval = -EAGAIN; | |
1da177e4 LT |
2232 | break; |
2233 | } | |
52bce7f8 PH |
2234 | if (signal_pending(current)) { |
2235 | retval = -ERESTARTSYS; | |
2236 | break; | |
2237 | } | |
52bce7f8 | 2238 | up_read(&tty->termios_rwsem); |
9356b535 | 2239 | |
37da7bbb LT |
2240 | timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, |
2241 | timeout); | |
9356b535 | 2242 | |
52bce7f8 PH |
2243 | down_read(&tty->termios_rwsem); |
2244 | continue; | |
1da177e4 LT |
2245 | } |
2246 | ||
53c5ee2c | 2247 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2248 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
ac8f3bf8 | 2249 | if (retval) |
1da177e4 LT |
2250 | break; |
2251 | } else { | |
2252 | int uncopied; | |
95ea90db PH |
2253 | |
2254 | /* Deal with packet mode. */ | |
2255 | if (packet && b == buf) { | |
2256 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { | |
2257 | retval = -EFAULT; | |
2258 | b--; | |
2259 | break; | |
2260 | } | |
2261 | nr--; | |
2262 | } | |
2263 | ||
1da177e4 LT |
2264 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2265 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2266 | if (uncopied) { | |
2267 | retval = -EFAULT; | |
2268 | break; | |
2269 | } | |
2270 | } | |
2271 | ||
6367ca72 | 2272 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2273 | |
2274 | if (b - buf >= minimum) | |
2275 | break; | |
2276 | if (time) | |
2277 | timeout = time; | |
2278 | } | |
2c5dc464 PH |
2279 | if (tail != ldata->read_tail) |
2280 | n_tty_kick_worker(tty); | |
42458f41 PH |
2281 | up_read(&tty->termios_rwsem); |
2282 | ||
1da177e4 | 2283 | remove_wait_queue(&tty->read_wait, &wait); |
1da177e4 | 2284 | if (!waitqueue_active(&tty->read_wait)) |
f6c8dbe6 | 2285 | ldata->minimum_to_wake = minimum; |
1da177e4 | 2286 | |
aebf0453 PH |
2287 | mutex_unlock(&ldata->atomic_read_lock); |
2288 | ||
40d5e090 PH |
2289 | if (b - buf) |
2290 | retval = b - buf; | |
1da177e4 LT |
2291 | |
2292 | return retval; | |
2293 | } | |
2294 | ||
2295 | /** | |
11a96d18 | 2296 | * n_tty_write - write function for tty |
1da177e4 LT |
2297 | * @tty: tty device |
2298 | * @file: file object | |
2299 | * @buf: userspace buffer pointer | |
2300 | * @nr: size of I/O | |
2301 | * | |
a88a69c9 | 2302 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2303 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2304 | * and other such events. Since the receive code will echo characters, |
2305 | * thus calling driver write methods, the output_lock is used in | |
2306 | * the output processing functions called here as well as in the | |
2307 | * echo processing function to protect the column state and space | |
2308 | * left in the buffer. | |
1da177e4 LT |
2309 | * |
2310 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2311 | * |
2312 | * Locking: output_lock to protect column state and space left | |
2313 | * (note that the process_output*() functions take this | |
2314 | * lock themselves) | |
1da177e4 | 2315 | */ |
4edf1827 | 2316 | |
11a96d18 | 2317 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2318 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2319 | { |
2320 | const unsigned char *b = buf; | |
97d9e28d | 2321 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2322 | int c; |
2323 | ssize_t retval = 0; | |
2324 | ||
2325 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2326 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2327 | retval = tty_check_change(tty); | |
2328 | if (retval) | |
2329 | return retval; | |
2330 | } | |
2331 | ||
9356b535 PH |
2332 | down_read(&tty->termios_rwsem); |
2333 | ||
a88a69c9 JP |
2334 | /* Write out any echoed characters that are still pending */ |
2335 | process_echoes(tty); | |
300a6204 | 2336 | |
1da177e4 LT |
2337 | add_wait_queue(&tty->write_wait, &wait); |
2338 | while (1) { | |
1da177e4 LT |
2339 | if (signal_pending(current)) { |
2340 | retval = -ERESTARTSYS; | |
2341 | break; | |
2342 | } | |
2343 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2344 | retval = -EIO; | |
2345 | break; | |
2346 | } | |
582f5590 | 2347 | if (O_OPOST(tty)) { |
1da177e4 | 2348 | while (nr > 0) { |
a88a69c9 | 2349 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2350 | if (num < 0) { |
2351 | if (num == -EAGAIN) | |
2352 | break; | |
2353 | retval = num; | |
2354 | goto break_out; | |
2355 | } | |
2356 | b += num; | |
2357 | nr -= num; | |
2358 | if (nr == 0) | |
2359 | break; | |
2360 | c = *b; | |
a88a69c9 | 2361 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2362 | break; |
2363 | b++; nr--; | |
2364 | } | |
f34d7a5b AC |
2365 | if (tty->ops->flush_chars) |
2366 | tty->ops->flush_chars(tty); | |
1da177e4 | 2367 | } else { |
4291086b PH |
2368 | struct n_tty_data *ldata = tty->disc_data; |
2369 | ||
d6afe27b | 2370 | while (nr > 0) { |
4291086b | 2371 | mutex_lock(&ldata->output_lock); |
f34d7a5b | 2372 | c = tty->ops->write(tty, b, nr); |
4291086b | 2373 | mutex_unlock(&ldata->output_lock); |
d6afe27b RZ |
2374 | if (c < 0) { |
2375 | retval = c; | |
2376 | goto break_out; | |
2377 | } | |
2378 | if (!c) | |
2379 | break; | |
2380 | b += c; | |
2381 | nr -= c; | |
1da177e4 | 2382 | } |
1da177e4 LT |
2383 | } |
2384 | if (!nr) | |
2385 | break; | |
2386 | if (file->f_flags & O_NONBLOCK) { | |
2387 | retval = -EAGAIN; | |
2388 | break; | |
2389 | } | |
9356b535 PH |
2390 | up_read(&tty->termios_rwsem); |
2391 | ||
97d9e28d | 2392 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
9356b535 PH |
2393 | |
2394 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2395 | } |
2396 | break_out: | |
1da177e4 | 2397 | remove_wait_queue(&tty->write_wait, &wait); |
ff8cb0fd TP |
2398 | if (b - buf != nr && tty->fasync) |
2399 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2400 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2401 | return (b - buf) ? b - buf : retval; |
2402 | } | |
2403 | ||
2404 | /** | |
11a96d18 | 2405 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2406 | * @tty: terminal device |
2407 | * @file: file accessing it | |
2408 | * @wait: poll table | |
2409 | * | |
2410 | * Called when the line discipline is asked to poll() for data or | |
2411 | * for special events. This code is not serialized with respect to | |
2412 | * other events save open/close. | |
2413 | * | |
2414 | * This code must be sure never to sleep through a hangup. | |
2415 | * Called without the kernel lock held - fine | |
1da177e4 | 2416 | */ |
4edf1827 | 2417 | |
11a96d18 | 2418 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2419 | poll_table *wait) |
1da177e4 | 2420 | { |
f6c8dbe6 | 2421 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2422 | unsigned int mask = 0; |
2423 | ||
2424 | poll_wait(file, &tty->read_wait, wait); | |
2425 | poll_wait(file, &tty->write_wait, wait); | |
1a48632f PH |
2426 | if (check_other_done(tty)) |
2427 | mask |= POLLHUP; | |
eafbe67f | 2428 | if (input_available_p(tty, 1)) |
1da177e4 LT |
2429 | mask |= POLLIN | POLLRDNORM; |
2430 | if (tty->packet && tty->link->ctrl_status) | |
2431 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
1da177e4 LT |
2432 | if (tty_hung_up_p(file)) |
2433 | mask |= POLLHUP; | |
2434 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2435 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2436 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2437 | else |
f6c8dbe6 | 2438 | ldata->minimum_to_wake = 1; |
1da177e4 | 2439 | } |
f34d7a5b AC |
2440 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2441 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2442 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2443 | mask |= POLLOUT | POLLWRNORM; |
2444 | return mask; | |
2445 | } | |
2446 | ||
57c94121 | 2447 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2448 | { |
bc5a5e3f | 2449 | size_t nr, head, tail; |
47afa7a5 | 2450 | |
a73d3d69 | 2451 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2452 | return 0; |
ba2e68ac JS |
2453 | head = ldata->canon_head; |
2454 | tail = ldata->read_tail; | |
bc5a5e3f | 2455 | nr = head - tail; |
47afa7a5 AC |
2456 | /* Skip EOF-chars.. */ |
2457 | while (head != tail) { | |
bc5a5e3f PH |
2458 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2459 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2460 | nr--; |
bc5a5e3f | 2461 | tail++; |
47afa7a5 AC |
2462 | } |
2463 | return nr; | |
2464 | } | |
2465 | ||
2466 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2467 | unsigned int cmd, unsigned long arg) | |
2468 | { | |
ba2e68ac | 2469 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2470 | int retval; |
2471 | ||
2472 | switch (cmd) { | |
2473 | case TIOCOUTQ: | |
2474 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2475 | case TIOCINQ: | |
6d76bd26 | 2476 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2477 | if (L_ICANON(tty)) |
57c94121 | 2478 | retval = inq_canon(ldata); |
6d76bd26 PH |
2479 | else |
2480 | retval = read_cnt(ldata); | |
2481 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2482 | return put_user(retval, (unsigned int __user *) arg); |
2483 | default: | |
2484 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2485 | } | |
2486 | } | |
2487 | ||
f6c8dbe6 PH |
2488 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2489 | { | |
2490 | struct n_tty_data *ldata = tty->disc_data; | |
2491 | ||
2492 | if (!waitqueue_active(&tty->read_wait)) { | |
2493 | if (on) | |
2494 | ldata->minimum_to_wake = 1; | |
2495 | else if (!tty->fasync) | |
2496 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2497 | } | |
2498 | } | |
2499 | ||
a352def2 | 2500 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2501 | .magic = TTY_LDISC_MAGIC, |
2502 | .name = "n_tty", | |
2503 | .open = n_tty_open, | |
2504 | .close = n_tty_close, | |
2505 | .flush_buffer = n_tty_flush_buffer, | |
11a96d18 AC |
2506 | .read = n_tty_read, |
2507 | .write = n_tty_write, | |
e10cc1df PF |
2508 | .ioctl = n_tty_ioctl, |
2509 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2510 | .poll = n_tty_poll, |
e10cc1df | 2511 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2512 | .write_wakeup = n_tty_write_wakeup, |
2513 | .fasync = n_tty_fasync, | |
24a89d1c | 2514 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2515 | }; |
572b9adb RG |
2516 | |
2517 | /** | |
2518 | * n_tty_inherit_ops - inherit N_TTY methods | |
2519 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2520 | * | |
593fb1ae | 2521 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2522 | * methods. |
2523 | */ | |
2524 | ||
2525 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2526 | { | |
2527 | *ops = tty_ldisc_N_TTY; | |
2528 | ops->owner = NULL; | |
2529 | ops->refcount = ops->flags = 0; | |
2530 | } | |
2531 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |