Commit | Line | Data |
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e3b3d0f5 | 1 | // SPDX-License-Identifier: GPL-1.0+ |
1da177e4 LT |
2 | /* |
3 | * n_tty.c --- implements the N_TTY line discipline. | |
4edf1827 | 4 | * |
1da177e4 LT |
5 | * This code used to be in tty_io.c, but things are getting hairy |
6 | * enough that it made sense to split things off. (The N_TTY | |
7 | * processing has changed so much that it's hardly recognizable, | |
8 | * anyway...) | |
9 | * | |
10 | * Note that the open routine for N_TTY is guaranteed never to return | |
11 | * an error. This is because Linux will fall back to setting a line | |
4edf1827 | 12 | * to N_TTY if it can not switch to any other line discipline. |
1da177e4 LT |
13 | * |
14 | * Written by Theodore Ts'o, Copyright 1994. | |
4edf1827 | 15 | * |
1da177e4 LT |
16 | * This file also contains code originally written by Linus Torvalds, |
17 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. | |
4edf1827 | 18 | * |
1da177e4 LT |
19 | * Reduced memory usage for older ARM systems - Russell King. |
20 | * | |
4edf1827 | 21 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
1da177e4 LT |
22 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
23 | * who actually finally proved there really was a race. | |
24 | * | |
25 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to | |
26 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. | |
11a96d18 | 27 | * Also fixed a bug in BLOCKING mode where n_tty_write returns |
1da177e4 LT |
28 | * EAGAIN |
29 | */ | |
30 | ||
31 | #include <linux/types.h> | |
32 | #include <linux/major.h> | |
33 | #include <linux/errno.h> | |
34 | #include <linux/signal.h> | |
35 | #include <linux/fcntl.h> | |
36 | #include <linux/sched.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/tty.h> | |
39 | #include <linux/timer.h> | |
40 | #include <linux/ctype.h> | |
41 | #include <linux/mm.h> | |
42 | #include <linux/string.h> | |
43 | #include <linux/slab.h> | |
44 | #include <linux/poll.h> | |
45 | #include <linux/bitops.h> | |
522ed776 MT |
46 | #include <linux/audit.h> |
47 | #include <linux/file.h> | |
300a6204 | 48 | #include <linux/uaccess.h> |
572b9adb | 49 | #include <linux/module.h> |
593fb1ae | 50 | #include <linux/ratelimit.h> |
86e35aea | 51 | #include <linux/vmalloc.h> |
1da177e4 | 52 | |
1da177e4 LT |
53 | |
54 | /* number of characters left in xmit buffer before select has we have room */ | |
55 | #define WAKEUP_CHARS 256 | |
56 | ||
57 | /* | |
58 | * This defines the low- and high-watermarks for throttling and | |
59 | * unthrottling the TTY driver. These watermarks are used for | |
60 | * controlling the space in the read buffer. | |
61 | */ | |
62 | #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ | |
bbd20759 | 63 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
1da177e4 | 64 | |
a88a69c9 JP |
65 | /* |
66 | * Special byte codes used in the echo buffer to represent operations | |
67 | * or special handling of characters. Bytes in the echo buffer that | |
68 | * are not part of such special blocks are treated as normal character | |
69 | * codes. | |
70 | */ | |
71 | #define ECHO_OP_START 0xff | |
72 | #define ECHO_OP_MOVE_BACK_COL 0x80 | |
73 | #define ECHO_OP_SET_CANON_COL 0x81 | |
74 | #define ECHO_OP_ERASE_TAB 0x82 | |
75 | ||
cbfd0340 PH |
76 | #define ECHO_COMMIT_WATERMARK 256 |
77 | #define ECHO_BLOCK 256 | |
78 | #define ECHO_DISCARD_WATERMARK N_TTY_BUF_SIZE - (ECHO_BLOCK + 32) | |
79 | ||
80 | ||
32f13521 PH |
81 | #undef N_TTY_TRACE |
82 | #ifdef N_TTY_TRACE | |
83 | # define n_tty_trace(f, args...) trace_printk(f, ##args) | |
84 | #else | |
85 | # define n_tty_trace(f, args...) | |
86 | #endif | |
87 | ||
70ece7a7 | 88 | struct n_tty_data { |
fb7aa03d PH |
89 | /* producer-published */ |
90 | size_t read_head; | |
70aca71f | 91 | size_t commit_head; |
fb7aa03d | 92 | size_t canon_head; |
9dfd16dd PH |
93 | size_t echo_head; |
94 | size_t echo_commit; | |
1075a6e2 | 95 | size_t echo_mark; |
1bb9d562 | 96 | DECLARE_BITMAP(char_map, 256); |
fb7aa03d PH |
97 | |
98 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c JS |
99 | unsigned long overrun_time; |
100 | int num_overrun; | |
101 | ||
24a89d1c PH |
102 | /* non-atomic */ |
103 | bool no_room; | |
104 | ||
fb7aa03d | 105 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c | 106 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
4d0ed182 | 107 | unsigned char push:1; |
3fe780b3 | 108 | |
fb7aa03d | 109 | /* shared by producer and consumer */ |
20bafb3d | 110 | char read_buf[N_TTY_BUF_SIZE]; |
3fe780b3 | 111 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
20bafb3d | 112 | unsigned char echo_buf[N_TTY_BUF_SIZE]; |
ba2e68ac | 113 | |
fb7aa03d PH |
114 | /* consumer-published */ |
115 | size_t read_tail; | |
40d5e090 | 116 | size_t line_start; |
fb7aa03d | 117 | |
fb7aa03d PH |
118 | /* protected by output lock */ |
119 | unsigned int column; | |
ba2e68ac | 120 | unsigned int canon_column; |
9dfd16dd | 121 | size_t echo_tail; |
bddc7152 JS |
122 | |
123 | struct mutex atomic_read_lock; | |
124 | struct mutex output_lock; | |
70ece7a7 JS |
125 | }; |
126 | ||
3d63b7e4 TH |
127 | #define MASK(x) ((x) & (N_TTY_BUF_SIZE - 1)) |
128 | ||
ce74117a PH |
129 | static inline size_t read_cnt(struct n_tty_data *ldata) |
130 | { | |
a2f73be8 | 131 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
132 | } |
133 | ||
bc5a5e3f PH |
134 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
135 | { | |
136 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
137 | } | |
138 | ||
139 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
140 | { | |
141 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
142 | } | |
143 | ||
addaebcc PH |
144 | static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) |
145 | { | |
ebec3f8f | 146 | smp_rmb(); /* Matches smp_wmb() in add_echo_byte(). */ |
addaebcc PH |
147 | return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; |
148 | } | |
149 | ||
150 | static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) | |
151 | { | |
152 | return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
153 | } | |
154 | ||
b97b3d9f GK |
155 | /* If we are not echoing the data, perhaps this is a secret so erase it */ |
156 | static void zero_buffer(struct tty_struct *tty, u8 *buffer, int size) | |
157 | { | |
158 | bool icanon = !!L_ICANON(tty); | |
159 | bool no_echo = !L_ECHO(tty); | |
160 | ||
161 | if (icanon && no_echo) | |
162 | memset(buffer, 0x00, size); | |
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 | 169 | size_t size = N_TTY_BUF_SIZE - tail; |
b97b3d9f | 170 | void *from = read_buf_addr(ldata, tail); |
679e7c29 PH |
171 | int uncopied; |
172 | ||
173 | if (n > size) { | |
309426ae | 174 | tty_audit_add_data(tty, from, size); |
679e7c29 | 175 | uncopied = copy_to_user(to, from, size); |
b97b3d9f | 176 | zero_buffer(tty, from, size - uncopied); |
679e7c29 PH |
177 | if (uncopied) |
178 | return uncopied; | |
179 | to += size; | |
180 | n -= size; | |
181 | from = ldata->read_buf; | |
182 | } | |
72586c60 | 183 | |
309426ae | 184 | tty_audit_add_data(tty, from, n); |
b97b3d9f GK |
185 | uncopied = copy_to_user(to, from, n); |
186 | zero_buffer(tty, from, n - uncopied); | |
187 | return uncopied; | |
72586c60 LA |
188 | } |
189 | ||
24a89d1c | 190 | /** |
2c5dc464 | 191 | * n_tty_kick_worker - start input worker (if required) |
24a89d1c PH |
192 | * @tty: terminal |
193 | * | |
2c5dc464 | 194 | * Re-schedules the flip buffer work if it may have stopped |
24a89d1c | 195 | * |
6d76bd26 PH |
196 | * Caller holds exclusive termios_rwsem |
197 | * or | |
198 | * n_tty_read()/consumer path: | |
199 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
200 | */ |
201 | ||
2c5dc464 | 202 | static void n_tty_kick_worker(struct tty_struct *tty) |
7879a9f9 | 203 | { |
24a89d1c PH |
204 | struct n_tty_data *ldata = tty->disc_data; |
205 | ||
2c5dc464 PH |
206 | /* Did the input worker stop? Restart it */ |
207 | if (unlikely(ldata->no_room)) { | |
24a89d1c PH |
208 | ldata->no_room = 0; |
209 | ||
ecbbfd44 | 210 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 211 | "scheduling with invalid itty\n"); |
21622939 PH |
212 | /* see if ldisc has been killed - if so, this means that |
213 | * even though the ldisc has been halted and ->buf.work | |
214 | * cancelled, ->buf.work is about to be rescheduled | |
215 | */ | |
216 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
217 | "scheduling buffer work for halted ldisc\n"); | |
e176058f | 218 | tty_buffer_restart_work(tty->port); |
ecbbfd44 | 219 | } |
55db4c64 LT |
220 | } |
221 | ||
9a4aec2d PH |
222 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
223 | { | |
224 | struct n_tty_data *ldata = tty->disc_data; | |
225 | ssize_t n = 0; | |
226 | ||
227 | if (!ldata->icanon) | |
70aca71f | 228 | n = ldata->commit_head - ldata->read_tail; |
9a4aec2d PH |
229 | else |
230 | n = ldata->canon_head - ldata->read_tail; | |
231 | return n; | |
232 | } | |
233 | ||
ee0bab83 PH |
234 | /** |
235 | * n_tty_write_wakeup - asynchronous I/O notifier | |
236 | * @tty: tty device | |
237 | * | |
238 | * Required for the ptys, serial driver etc. since processes | |
239 | * that attach themselves to the master and rely on ASYNC | |
240 | * IO must be woken up | |
241 | */ | |
242 | ||
243 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
244 | { | |
7bccc365 PH |
245 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
246 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
ee0bab83 PH |
247 | } |
248 | ||
4a23a4df | 249 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 250 | { |
a342846f PH |
251 | struct n_tty_data *ldata = tty->disc_data; |
252 | ||
6367ca72 PH |
253 | /* |
254 | * Check the remaining room for the input canonicalization | |
255 | * mode. We don't want to throttle the driver if we're in | |
256 | * canonical mode and don't have a newline yet! | |
257 | */ | |
a342846f PH |
258 | if (ldata->icanon && ldata->canon_head == ldata->read_tail) |
259 | return; | |
260 | ||
6367ca72 PH |
261 | while (1) { |
262 | int throttled; | |
263 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
5e28cca1 | 264 | if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE) |
6367ca72 PH |
265 | break; |
266 | throttled = tty_throttle_safe(tty); | |
267 | if (!throttled) | |
268 | break; | |
269 | } | |
270 | __tty_set_flow_change(tty, 0); | |
271 | } | |
272 | ||
4b293492 | 273 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 274 | { |
6d27a63c | 275 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { |
3afb1b39 PH |
276 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) |
277 | return; | |
2c5dc464 | 278 | n_tty_kick_worker(tty); |
6d27a63c | 279 | tty_wakeup(tty->link); |
3afb1b39 PH |
280 | return; |
281 | } | |
282 | ||
6367ca72 PH |
283 | /* If there is enough space in the read buffer now, let the |
284 | * low-level driver know. We use chars_in_buffer() to | |
285 | * check the buffer, as it now knows about canonical mode. | |
286 | * Otherwise, if the driver is throttled and the line is | |
287 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
288 | * we won't get any more characters. | |
289 | */ | |
290 | ||
291 | while (1) { | |
292 | int unthrottled; | |
293 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
294 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
295 | break; | |
2c5dc464 | 296 | n_tty_kick_worker(tty); |
6367ca72 PH |
297 | unthrottled = tty_unthrottle_safe(tty); |
298 | if (!unthrottled) | |
299 | break; | |
300 | } | |
301 | __tty_set_flow_change(tty, 0); | |
302 | } | |
303 | ||
17b82060 AC |
304 | /** |
305 | * put_tty_queue - add character to tty | |
306 | * @c: character | |
57c94121 | 307 | * @ldata: n_tty data |
17b82060 | 308 | * |
6d76bd26 PH |
309 | * Add a character to the tty read_buf queue. |
310 | * | |
311 | * n_tty_receive_buf()/producer path: | |
312 | * caller holds non-exclusive termios_rwsem | |
17b82060 AC |
313 | */ |
314 | ||
19e2ad6a | 315 | static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 316 | { |
8bfbe2de CR |
317 | *read_buf_addr(ldata, ldata->read_head) = c; |
318 | ldata->read_head++; | |
1da177e4 LT |
319 | } |
320 | ||
1da177e4 LT |
321 | /** |
322 | * reset_buffer_flags - reset buffer state | |
323 | * @tty: terminal to reset | |
324 | * | |
25518c68 PH |
325 | * Reset the read buffer counters and clear the flags. |
326 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 327 | * |
6d76bd26 PH |
328 | * Locking: caller holds exclusive termios_rwsem |
329 | * (or locking is not required) | |
1da177e4 | 330 | */ |
a88a69c9 | 331 | |
b66f4fa5 | 332 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 333 | { |
a73d3d69 | 334 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
70aca71f | 335 | ldata->commit_head = 0; |
40d5e090 | 336 | ldata->line_start = 0; |
a88a69c9 | 337 | |
a73d3d69 | 338 | ldata->erasing = 0; |
3fe780b3 | 339 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 | 340 | ldata->push = 0; |
1da177e4 LT |
341 | } |
342 | ||
a30737ab PH |
343 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
344 | { | |
345 | unsigned long flags; | |
346 | ||
a30737ab | 347 | if (tty->link->packet) { |
54e8e5fc | 348 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
a30737ab | 349 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; |
54e8e5fc | 350 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
e81107d4 | 351 | wake_up_interruptible(&tty->link->read_wait); |
a30737ab | 352 | } |
a30737ab PH |
353 | } |
354 | ||
1da177e4 LT |
355 | /** |
356 | * n_tty_flush_buffer - clean input queue | |
357 | * @tty: terminal device | |
358 | * | |
25518c68 PH |
359 | * Flush the input buffer. Called when the tty layer wants the |
360 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
361 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 362 | * |
6d76bd26 PH |
363 | * Holds termios_rwsem to exclude producer/consumer while |
364 | * buffer indices are reset. | |
365 | * | |
366 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 367 | */ |
4edf1827 AC |
368 | |
369 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 370 | { |
6d76bd26 | 371 | down_write(&tty->termios_rwsem); |
b66f4fa5 | 372 | reset_buffer_flags(tty->disc_data); |
2c5dc464 | 373 | n_tty_kick_worker(tty); |
4edf1827 | 374 | |
a30737ab PH |
375 | if (tty->link) |
376 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 377 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
378 | } |
379 | ||
1da177e4 LT |
380 | /** |
381 | * is_utf8_continuation - utf8 multibyte check | |
382 | * @c: byte to check | |
383 | * | |
384 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
385 | * character. We use this to correctly compute the on screen size | |
386 | * of the character when printing | |
387 | */ | |
4edf1827 | 388 | |
1da177e4 LT |
389 | static inline int is_utf8_continuation(unsigned char c) |
390 | { | |
391 | return (c & 0xc0) == 0x80; | |
392 | } | |
393 | ||
394 | /** | |
395 | * is_continuation - multibyte check | |
396 | * @c: byte to check | |
397 | * | |
398 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
399 | * character and the terminal is in unicode mode. | |
400 | */ | |
4edf1827 | 401 | |
1da177e4 LT |
402 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
403 | { | |
404 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
405 | } | |
406 | ||
407 | /** | |
a88a69c9 | 408 | * do_output_char - output one character |
1da177e4 LT |
409 | * @c: character (or partial unicode symbol) |
410 | * @tty: terminal device | |
a88a69c9 | 411 | * @space: space available in tty driver write buffer |
1da177e4 | 412 | * |
a88a69c9 JP |
413 | * This is a helper function that handles one output character |
414 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
415 | * doing OPOST processing and putting the results in the |
416 | * tty driver's write buffer. | |
a88a69c9 JP |
417 | * |
418 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
419 | * and NLDLY. They simply aren't relevant in the world today. | |
420 | * If you ever need them, add them here. | |
1da177e4 | 421 | * |
a88a69c9 JP |
422 | * Returns the number of bytes of buffer space used or -1 if |
423 | * no space left. | |
424 | * | |
425 | * Locking: should be called under the output_lock to protect | |
426 | * the column state and space left in the buffer | |
1da177e4 | 427 | */ |
4edf1827 | 428 | |
a88a69c9 | 429 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 430 | { |
53c5ee2c | 431 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 432 | int spaces; |
1da177e4 | 433 | |
1da177e4 LT |
434 | if (!space) |
435 | return -1; | |
300a6204 | 436 | |
a88a69c9 JP |
437 | switch (c) { |
438 | case '\n': | |
439 | if (O_ONLRET(tty)) | |
53c5ee2c | 440 | ldata->column = 0; |
a88a69c9 JP |
441 | if (O_ONLCR(tty)) { |
442 | if (space < 2) | |
443 | return -1; | |
ba2e68ac | 444 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 445 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
446 | return 2; |
447 | } | |
ba2e68ac | 448 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
449 | break; |
450 | case '\r': | |
53c5ee2c | 451 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
452 | return 0; |
453 | if (O_OCRNL(tty)) { | |
454 | c = '\n'; | |
455 | if (O_ONLRET(tty)) | |
ba2e68ac | 456 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 457 | break; |
a88a69c9 | 458 | } |
ba2e68ac | 459 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
460 | break; |
461 | case '\t': | |
53c5ee2c | 462 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
463 | if (O_TABDLY(tty) == XTABS) { |
464 | if (space < spaces) | |
465 | return -1; | |
53c5ee2c | 466 | ldata->column += spaces; |
a88a69c9 JP |
467 | tty->ops->write(tty, " ", spaces); |
468 | return spaces; | |
1da177e4 | 469 | } |
53c5ee2c | 470 | ldata->column += spaces; |
a88a69c9 JP |
471 | break; |
472 | case '\b': | |
53c5ee2c JS |
473 | if (ldata->column > 0) |
474 | ldata->column--; | |
a88a69c9 JP |
475 | break; |
476 | default: | |
a59c0d6f JP |
477 | if (!iscntrl(c)) { |
478 | if (O_OLCUC(tty)) | |
479 | c = toupper(c); | |
480 | if (!is_continuation(c, tty)) | |
53c5ee2c | 481 | ldata->column++; |
a59c0d6f | 482 | } |
a88a69c9 | 483 | break; |
1da177e4 | 484 | } |
a88a69c9 | 485 | |
f34d7a5b | 486 | tty_put_char(tty, c); |
a88a69c9 JP |
487 | return 1; |
488 | } | |
489 | ||
490 | /** | |
491 | * process_output - output post processor | |
492 | * @c: character (or partial unicode symbol) | |
493 | * @tty: terminal device | |
494 | * | |
ee5aa7b8 JP |
495 | * Output one character with OPOST processing. |
496 | * Returns -1 when the output device is full and the character | |
497 | * must be retried. | |
a88a69c9 JP |
498 | * |
499 | * Locking: output_lock to protect column state and space left | |
500 | * (also, this is called from n_tty_write under the | |
501 | * tty layer write lock) | |
502 | */ | |
503 | ||
504 | static int process_output(unsigned char c, struct tty_struct *tty) | |
505 | { | |
bddc7152 | 506 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
507 | int space, retval; |
508 | ||
bddc7152 | 509 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
510 | |
511 | space = tty_write_room(tty); | |
512 | retval = do_output_char(c, tty, space); | |
513 | ||
bddc7152 | 514 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
515 | if (retval < 0) |
516 | return -1; | |
517 | else | |
518 | return 0; | |
1da177e4 LT |
519 | } |
520 | ||
521 | /** | |
a88a69c9 | 522 | * process_output_block - block post processor |
1da177e4 | 523 | * @tty: terminal device |
ee5aa7b8 JP |
524 | * @buf: character buffer |
525 | * @nr: number of bytes to output | |
526 | * | |
527 | * Output a block of characters with OPOST processing. | |
528 | * Returns the number of characters output. | |
1da177e4 LT |
529 | * |
530 | * This path is used to speed up block console writes, among other | |
531 | * things when processing blocks of output data. It handles only | |
532 | * the simple cases normally found and helps to generate blocks of | |
533 | * symbols for the console driver and thus improve performance. | |
534 | * | |
a88a69c9 JP |
535 | * Locking: output_lock to protect column state and space left |
536 | * (also, this is called from n_tty_write under the | |
537 | * tty layer write lock) | |
1da177e4 | 538 | */ |
4edf1827 | 539 | |
a88a69c9 JP |
540 | static ssize_t process_output_block(struct tty_struct *tty, |
541 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 542 | { |
53c5ee2c | 543 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 544 | int space; |
bbd20759 | 545 | int i; |
1da177e4 LT |
546 | const unsigned char *cp; |
547 | ||
bddc7152 | 548 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 549 | |
f34d7a5b | 550 | space = tty_write_room(tty); |
300a6204 | 551 | if (!space) { |
bddc7152 | 552 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 553 | return 0; |
a88a69c9 | 554 | } |
1da177e4 LT |
555 | if (nr > space) |
556 | nr = space; | |
557 | ||
558 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
559 | unsigned char c = *cp; |
560 | ||
561 | switch (c) { | |
1da177e4 LT |
562 | case '\n': |
563 | if (O_ONLRET(tty)) | |
53c5ee2c | 564 | ldata->column = 0; |
1da177e4 LT |
565 | if (O_ONLCR(tty)) |
566 | goto break_out; | |
ba2e68ac | 567 | ldata->canon_column = ldata->column; |
1da177e4 LT |
568 | break; |
569 | case '\r': | |
53c5ee2c | 570 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
571 | goto break_out; |
572 | if (O_OCRNL(tty)) | |
573 | goto break_out; | |
ba2e68ac | 574 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
575 | break; |
576 | case '\t': | |
577 | goto break_out; | |
578 | case '\b': | |
53c5ee2c JS |
579 | if (ldata->column > 0) |
580 | ldata->column--; | |
1da177e4 LT |
581 | break; |
582 | default: | |
a59c0d6f JP |
583 | if (!iscntrl(c)) { |
584 | if (O_OLCUC(tty)) | |
585 | goto break_out; | |
586 | if (!is_continuation(c, tty)) | |
53c5ee2c | 587 | ldata->column++; |
a59c0d6f | 588 | } |
1da177e4 LT |
589 | break; |
590 | } | |
591 | } | |
592 | break_out: | |
f34d7a5b | 593 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 594 | |
bddc7152 | 595 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
596 | return i; |
597 | } | |
598 | ||
a88a69c9 JP |
599 | /** |
600 | * process_echoes - write pending echo characters | |
601 | * @tty: terminal device | |
602 | * | |
603 | * Write previously buffered echo (and other ldisc-generated) | |
604 | * characters to the tty. | |
605 | * | |
606 | * Characters generated by the ldisc (including echoes) need to | |
607 | * be buffered because the driver's write buffer can fill during | |
608 | * heavy program output. Echoing straight to the driver will | |
609 | * often fail under these conditions, causing lost characters and | |
610 | * resulting mismatches of ldisc state information. | |
611 | * | |
612 | * Since the ldisc state must represent the characters actually sent | |
613 | * to the driver at the time of the write, operations like certain | |
614 | * changes in column state are also saved in the buffer and executed | |
615 | * here. | |
616 | * | |
617 | * A circular fifo buffer is used so that the most recent characters | |
618 | * are prioritized. Also, when control characters are echoed with a | |
619 | * prefixed "^", the pair is treated atomically and thus not separated. | |
620 | * | |
019ebdf9 | 621 | * Locking: callers must hold output_lock |
a88a69c9 JP |
622 | */ |
623 | ||
bc5b1ec5 | 624 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 625 | { |
53c5ee2c | 626 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 627 | int space, old_space; |
addaebcc | 628 | size_t tail; |
a88a69c9 | 629 | unsigned char c; |
a88a69c9 | 630 | |
bc5b1ec5 | 631 | old_space = space = tty_write_room(tty); |
a88a69c9 | 632 | |
addaebcc | 633 | tail = ldata->echo_tail; |
ebec3f8f | 634 | while (MASK(ldata->echo_commit) != MASK(tail)) { |
addaebcc | 635 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
636 | if (c == ECHO_OP_START) { |
637 | unsigned char op; | |
a88a69c9 JP |
638 | int no_space_left = 0; |
639 | ||
ebec3f8f TH |
640 | /* |
641 | * Since add_echo_byte() is called without holding | |
642 | * output_lock, we might see only portion of multi-byte | |
643 | * operation. | |
644 | */ | |
645 | if (MASK(ldata->echo_commit) == MASK(tail + 1)) | |
646 | goto not_yet_stored; | |
a88a69c9 JP |
647 | /* |
648 | * If the buffer byte is the start of a multi-byte | |
649 | * operation, get the next byte, which is either the | |
650 | * op code or a control character value. | |
651 | */ | |
addaebcc | 652 | op = echo_buf(ldata, tail + 1); |
300a6204 | 653 | |
a88a69c9 JP |
654 | switch (op) { |
655 | unsigned int num_chars, num_bs; | |
656 | ||
657 | case ECHO_OP_ERASE_TAB: | |
ebec3f8f TH |
658 | if (MASK(ldata->echo_commit) == MASK(tail + 2)) |
659 | goto not_yet_stored; | |
addaebcc | 660 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
661 | |
662 | /* | |
663 | * Determine how many columns to go back | |
664 | * in order to erase the tab. | |
665 | * This depends on the number of columns | |
666 | * used by other characters within the tab | |
667 | * area. If this (modulo 8) count is from | |
668 | * the start of input rather than from a | |
669 | * previous tab, we offset by canon column. | |
670 | * Otherwise, tab spacing is normal. | |
671 | */ | |
672 | if (!(num_chars & 0x80)) | |
ba2e68ac | 673 | num_chars += ldata->canon_column; |
a88a69c9 JP |
674 | num_bs = 8 - (num_chars & 7); |
675 | ||
676 | if (num_bs > space) { | |
677 | no_space_left = 1; | |
678 | break; | |
679 | } | |
680 | space -= num_bs; | |
681 | while (num_bs--) { | |
682 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
683 | if (ldata->column > 0) |
684 | ldata->column--; | |
a88a69c9 | 685 | } |
addaebcc | 686 | tail += 3; |
a88a69c9 JP |
687 | break; |
688 | ||
689 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 690 | ldata->canon_column = ldata->column; |
addaebcc | 691 | tail += 2; |
a88a69c9 JP |
692 | break; |
693 | ||
694 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
695 | if (ldata->column > 0) |
696 | ldata->column--; | |
addaebcc | 697 | tail += 2; |
a88a69c9 JP |
698 | break; |
699 | ||
700 | case ECHO_OP_START: | |
701 | /* This is an escaped echo op start code */ | |
702 | if (!space) { | |
703 | no_space_left = 1; | |
704 | break; | |
705 | } | |
706 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 707 | ldata->column++; |
a88a69c9 | 708 | space--; |
addaebcc | 709 | tail += 2; |
a88a69c9 JP |
710 | break; |
711 | ||
712 | default: | |
a88a69c9 | 713 | /* |
62b26358 JP |
714 | * If the op is not a special byte code, |
715 | * it is a ctrl char tagged to be echoed | |
716 | * as "^X" (where X is the letter | |
717 | * representing the control char). | |
718 | * Note that we must ensure there is | |
719 | * enough space for the whole ctrl pair. | |
720 | * | |
a88a69c9 | 721 | */ |
62b26358 JP |
722 | if (space < 2) { |
723 | no_space_left = 1; | |
724 | break; | |
725 | } | |
726 | tty_put_char(tty, '^'); | |
727 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 728 | ldata->column += 2; |
62b26358 | 729 | space -= 2; |
addaebcc | 730 | tail += 2; |
a88a69c9 JP |
731 | } |
732 | ||
733 | if (no_space_left) | |
734 | break; | |
735 | } else { | |
582f5590 | 736 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
737 | int retval = do_output_char(c, tty, space); |
738 | if (retval < 0) | |
739 | break; | |
740 | space -= retval; | |
741 | } else { | |
742 | if (!space) | |
743 | break; | |
744 | tty_put_char(tty, c); | |
745 | space -= 1; | |
746 | } | |
addaebcc | 747 | tail += 1; |
a88a69c9 | 748 | } |
a88a69c9 JP |
749 | } |
750 | ||
cbfd0340 PH |
751 | /* If the echo buffer is nearly full (so that the possibility exists |
752 | * of echo overrun before the next commit), then discard enough | |
753 | * data at the tail to prevent a subsequent overrun */ | |
ebec3f8f TH |
754 | while (ldata->echo_commit > tail && |
755 | ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 756 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 757 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
758 | tail += 3; |
759 | else | |
760 | tail += 2; | |
761 | } else | |
762 | tail++; | |
763 | } | |
764 | ||
ebec3f8f | 765 | not_yet_stored: |
addaebcc | 766 | ldata->echo_tail = tail; |
bc5b1ec5 | 767 | return old_space - space; |
019ebdf9 PH |
768 | } |
769 | ||
770 | static void commit_echoes(struct tty_struct *tty) | |
771 | { | |
772 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 773 | size_t nr, old, echoed; |
cbfd0340 PH |
774 | size_t head; |
775 | ||
ebec3f8f | 776 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 777 | head = ldata->echo_head; |
1075a6e2 | 778 | ldata->echo_mark = head; |
cbfd0340 PH |
779 | old = ldata->echo_commit - ldata->echo_tail; |
780 | ||
781 | /* Process committed echoes if the accumulated # of bytes | |
782 | * is over the threshold (and try again each time another | |
783 | * block is accumulated) */ | |
784 | nr = head - ldata->echo_tail; | |
ebec3f8f TH |
785 | if (nr < ECHO_COMMIT_WATERMARK || |
786 | (nr % ECHO_BLOCK > old % ECHO_BLOCK)) { | |
787 | mutex_unlock(&ldata->output_lock); | |
cbfd0340 | 788 | return; |
ebec3f8f | 789 | } |
a88a69c9 | 790 | |
cbfd0340 | 791 | ldata->echo_commit = head; |
bc5b1ec5 | 792 | echoed = __process_echoes(tty); |
bddc7152 | 793 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 794 | |
bc5b1ec5 | 795 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
796 | tty->ops->flush_chars(tty); |
797 | } | |
798 | ||
019ebdf9 | 799 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
800 | { |
801 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 802 | size_t echoed; |
17bd7907 | 803 | |
e2613be5 | 804 | if (ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
805 | return; |
806 | ||
807 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 808 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 809 | echoed = __process_echoes(tty); |
019ebdf9 PH |
810 | mutex_unlock(&ldata->output_lock); |
811 | ||
bc5b1ec5 | 812 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 813 | tty->ops->flush_chars(tty); |
17bd7907 PH |
814 | } |
815 | ||
1075a6e2 | 816 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
817 | static void flush_echoes(struct tty_struct *tty) |
818 | { | |
819 | struct n_tty_data *ldata = tty->disc_data; | |
820 | ||
39434abd PH |
821 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
822 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
823 | return; |
824 | ||
825 | mutex_lock(&ldata->output_lock); | |
826 | ldata->echo_commit = ldata->echo_head; | |
827 | __process_echoes(tty); | |
828 | mutex_unlock(&ldata->output_lock); | |
829 | } | |
830 | ||
a88a69c9 JP |
831 | /** |
832 | * add_echo_byte - add a byte to the echo buffer | |
833 | * @c: unicode byte to echo | |
57c94121 | 834 | * @ldata: n_tty data |
a88a69c9 JP |
835 | * |
836 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
837 | */ |
838 | ||
cbfd0340 | 839 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 840 | { |
ebec3f8f TH |
841 | *echo_buf_addr(ldata, ldata->echo_head) = c; |
842 | smp_wmb(); /* Matches smp_rmb() in echo_buf(). */ | |
843 | ldata->echo_head++; | |
a88a69c9 JP |
844 | } |
845 | ||
846 | /** | |
847 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 848 | * @ldata: n_tty data |
a88a69c9 JP |
849 | * |
850 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
851 | */ |
852 | ||
57c94121 | 853 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 854 | { |
57c94121 JS |
855 | add_echo_byte(ECHO_OP_START, ldata); |
856 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
857 | } |
858 | ||
859 | /** | |
860 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 861 | * @ldata: n_tty data |
a88a69c9 JP |
862 | * |
863 | * Add an operation to the echo buffer to set the canon column | |
864 | * to the current column. | |
a88a69c9 JP |
865 | */ |
866 | ||
57c94121 | 867 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 868 | { |
57c94121 JS |
869 | add_echo_byte(ECHO_OP_START, ldata); |
870 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
871 | } |
872 | ||
873 | /** | |
874 | * echo_erase_tab - add operation to erase a tab | |
875 | * @num_chars: number of character columns already used | |
876 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 877 | * @ldata: n_tty data |
a88a69c9 JP |
878 | * |
879 | * Add an operation to the echo buffer to erase a tab. | |
880 | * | |
881 | * Called by the eraser function, which knows how many character | |
882 | * columns have been used since either a previous tab or the start | |
883 | * of input. This information will be used later, along with | |
884 | * canon column (if applicable), to go back the correct number | |
885 | * of columns. | |
a88a69c9 JP |
886 | */ |
887 | ||
888 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 889 | struct n_tty_data *ldata) |
a88a69c9 | 890 | { |
57c94121 JS |
891 | add_echo_byte(ECHO_OP_START, ldata); |
892 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
893 | |
894 | /* We only need to know this modulo 8 (tab spacing) */ | |
895 | num_chars &= 7; | |
896 | ||
897 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
898 | if (after_tab) | |
899 | num_chars |= 0x80; | |
300a6204 | 900 | |
57c94121 | 901 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
902 | } |
903 | ||
904 | /** | |
905 | * echo_char_raw - echo a character raw | |
906 | * @c: unicode byte to echo | |
907 | * @tty: terminal device | |
908 | * | |
909 | * Echo user input back onto the screen. This must be called only when | |
910 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
911 | * | |
912 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
913 | */ |
914 | ||
57c94121 | 915 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 916 | { |
a88a69c9 | 917 | if (c == ECHO_OP_START) { |
57c94121 JS |
918 | add_echo_byte(ECHO_OP_START, ldata); |
919 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 920 | } else { |
57c94121 | 921 | add_echo_byte(c, ldata); |
a88a69c9 | 922 | } |
a88a69c9 | 923 | } |
1da177e4 | 924 | |
1da177e4 | 925 | /** |
a88a69c9 | 926 | * echo_char - echo a character |
1da177e4 LT |
927 | * @c: unicode byte to echo |
928 | * @tty: terminal device | |
929 | * | |
4edf1827 | 930 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 931 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 932 | * |
62b26358 JP |
933 | * This variant tags control characters to be echoed as "^X" |
934 | * (where X is the letter representing the control char). | |
1da177e4 LT |
935 | */ |
936 | ||
937 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
938 | { | |
bddc7152 JS |
939 | struct n_tty_data *ldata = tty->disc_data; |
940 | ||
a88a69c9 | 941 | if (c == ECHO_OP_START) { |
57c94121 JS |
942 | add_echo_byte(ECHO_OP_START, ldata); |
943 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 944 | } else { |
62b26358 | 945 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
946 | add_echo_byte(ECHO_OP_START, ldata); |
947 | add_echo_byte(c, ldata); | |
a88a69c9 | 948 | } |
1da177e4 LT |
949 | } |
950 | ||
17b82060 | 951 | /** |
a88a69c9 | 952 | * finish_erasing - complete erase |
57c94121 | 953 | * @ldata: n_tty data |
17b82060 | 954 | */ |
a88a69c9 | 955 | |
57c94121 | 956 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 957 | { |
53c5ee2c | 958 | if (ldata->erasing) { |
57c94121 | 959 | echo_char_raw('/', ldata); |
53c5ee2c | 960 | ldata->erasing = 0; |
1da177e4 LT |
961 | } |
962 | } | |
963 | ||
964 | /** | |
965 | * eraser - handle erase function | |
966 | * @c: character input | |
967 | * @tty: terminal device | |
968 | * | |
3a4fa0a2 | 969 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
970 | * present in the stream from the driver layer. Handles the complexities |
971 | * of UTF-8 multibyte symbols. | |
17b82060 | 972 | * |
6d76bd26 PH |
973 | * n_tty_receive_buf()/producer path: |
974 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 975 | */ |
4edf1827 | 976 | |
1da177e4 LT |
977 | static void eraser(unsigned char c, struct tty_struct *tty) |
978 | { | |
53c5ee2c | 979 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 980 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
981 | size_t head; |
982 | size_t cnt; | |
983 | int seen_alnums; | |
1da177e4 | 984 | |
ba2e68ac | 985 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 986 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
987 | return; |
988 | } | |
989 | if (c == ERASE_CHAR(tty)) | |
990 | kill_type = ERASE; | |
991 | else if (c == WERASE_CHAR(tty)) | |
992 | kill_type = WERASE; | |
993 | else { | |
994 | if (!L_ECHO(tty)) { | |
ba2e68ac | 995 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
996 | return; |
997 | } | |
998 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 999 | ldata->read_head = ldata->canon_head; |
57c94121 | 1000 | finish_erasing(ldata); |
1da177e4 LT |
1001 | echo_char(KILL_CHAR(tty), tty); |
1002 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
1003 | if (L_ECHOK(tty)) | |
57c94121 | 1004 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1005 | return; |
1006 | } | |
1007 | kill_type = KILL; | |
1008 | } | |
1009 | ||
1010 | seen_alnums = 0; | |
3d63b7e4 | 1011 | while (MASK(ldata->read_head) != MASK(ldata->canon_head)) { |
ba2e68ac | 1012 | head = ldata->read_head; |
1da177e4 LT |
1013 | |
1014 | /* erase a single possibly multibyte character */ | |
1015 | do { | |
bc5a5e3f PH |
1016 | head--; |
1017 | c = read_buf(ldata, head); | |
3d63b7e4 TH |
1018 | } while (is_continuation(c, tty) && |
1019 | MASK(head) != MASK(ldata->canon_head)); | |
1da177e4 LT |
1020 | |
1021 | /* do not partially erase */ | |
1022 | if (is_continuation(c, tty)) | |
1023 | break; | |
1024 | ||
1025 | if (kill_type == WERASE) { | |
1026 | /* Equivalent to BSD's ALTWERASE. */ | |
1027 | if (isalnum(c) || c == '_') | |
1028 | seen_alnums++; | |
1029 | else if (seen_alnums) | |
1030 | break; | |
1031 | } | |
bc5a5e3f | 1032 | cnt = ldata->read_head - head; |
ba2e68ac | 1033 | ldata->read_head = head; |
1da177e4 LT |
1034 | if (L_ECHO(tty)) { |
1035 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1036 | if (!ldata->erasing) { |
57c94121 | 1037 | echo_char_raw('\\', ldata); |
53c5ee2c | 1038 | ldata->erasing = 1; |
1da177e4 LT |
1039 | } |
1040 | /* if cnt > 1, output a multi-byte character */ | |
1041 | echo_char(c, tty); | |
1042 | while (--cnt > 0) { | |
bc5a5e3f PH |
1043 | head++; |
1044 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1045 | echo_move_back_col(ldata); |
1da177e4 LT |
1046 | } |
1047 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1048 | echo_char(ERASE_CHAR(tty), tty); | |
1049 | } else if (c == '\t') { | |
a88a69c9 JP |
1050 | unsigned int num_chars = 0; |
1051 | int after_tab = 0; | |
bc5a5e3f | 1052 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1053 | |
1054 | /* | |
1055 | * Count the columns used for characters | |
1056 | * since the start of input or after a | |
1057 | * previous tab. | |
1058 | * This info is used to go back the correct | |
1059 | * number of columns. | |
1060 | */ | |
3d63b7e4 | 1061 | while (MASK(tail) != MASK(ldata->canon_head)) { |
bc5a5e3f PH |
1062 | tail--; |
1063 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1064 | if (c == '\t') { |
1065 | after_tab = 1; | |
1066 | break; | |
300a6204 | 1067 | } else if (iscntrl(c)) { |
1da177e4 | 1068 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1069 | num_chars += 2; |
1070 | } else if (!is_continuation(c, tty)) { | |
1071 | num_chars++; | |
1072 | } | |
1da177e4 | 1073 | } |
57c94121 | 1074 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1075 | } else { |
1076 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1077 | echo_char_raw('\b', ldata); |
1078 | echo_char_raw(' ', ldata); | |
1079 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1080 | } |
1081 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1082 | echo_char_raw('\b', ldata); |
1083 | echo_char_raw(' ', ldata); | |
1084 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1085 | } |
1086 | } | |
1087 | } | |
1088 | if (kill_type == ERASE) | |
1089 | break; | |
1090 | } | |
ba2e68ac | 1091 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1092 | finish_erasing(ldata); |
1da177e4 LT |
1093 | } |
1094 | ||
1095 | /** | |
1096 | * isig - handle the ISIG optio | |
1097 | * @sig: signal | |
1098 | * @tty: terminal | |
1da177e4 | 1099 | * |
8c985d18 PH |
1100 | * Called when a signal is being sent due to terminal input. |
1101 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1102 | * |
d2b6f447 PH |
1103 | * Performs input and output flush if !NOFLSH. In this context, the echo |
1104 | * buffer is 'output'. The signal is processed first to alert any current | |
1105 | * readers or writers to discontinue and exit their i/o loops. | |
1106 | * | |
8c985d18 | 1107 | * Locking: ctrl_lock |
1da177e4 | 1108 | */ |
4edf1827 | 1109 | |
3b19e032 | 1110 | static void __isig(int sig, struct tty_struct *tty) |
1da177e4 | 1111 | { |
8c985d18 PH |
1112 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1113 | if (tty_pgrp) { | |
1114 | kill_pgrp(tty_pgrp, sig, 1); | |
1115 | put_pid(tty_pgrp); | |
1da177e4 | 1116 | } |
3b19e032 | 1117 | } |
d2b6f447 | 1118 | |
3b19e032 PH |
1119 | static void isig(int sig, struct tty_struct *tty) |
1120 | { | |
1121 | struct n_tty_data *ldata = tty->disc_data; | |
1122 | ||
1123 | if (L_NOFLSH(tty)) { | |
1124 | /* signal only */ | |
1125 | __isig(sig, tty); | |
1126 | ||
1127 | } else { /* signal and flush */ | |
d2b6f447 PH |
1128 | up_read(&tty->termios_rwsem); |
1129 | down_write(&tty->termios_rwsem); | |
1130 | ||
3b19e032 PH |
1131 | __isig(sig, tty); |
1132 | ||
d2b6f447 PH |
1133 | /* clear echo buffer */ |
1134 | mutex_lock(&ldata->output_lock); | |
1135 | ldata->echo_head = ldata->echo_tail = 0; | |
1136 | ldata->echo_mark = ldata->echo_commit = 0; | |
1137 | mutex_unlock(&ldata->output_lock); | |
1138 | ||
1139 | /* clear output buffer */ | |
1140 | tty_driver_flush_buffer(tty); | |
1141 | ||
1142 | /* clear input buffer */ | |
1143 | reset_buffer_flags(tty->disc_data); | |
1144 | ||
1145 | /* notify pty master of flush */ | |
1146 | if (tty->link) | |
1147 | n_tty_packet_mode_flush(tty); | |
1148 | ||
1149 | up_write(&tty->termios_rwsem); | |
1150 | down_read(&tty->termios_rwsem); | |
1151 | } | |
1da177e4 LT |
1152 | } |
1153 | ||
1154 | /** | |
1155 | * n_tty_receive_break - handle break | |
1156 | * @tty: terminal | |
1157 | * | |
1158 | * An RS232 break event has been hit in the incoming bitstream. This | |
1159 | * can cause a variety of events depending upon the termios settings. | |
1160 | * | |
6d76bd26 PH |
1161 | * n_tty_receive_buf()/producer path: |
1162 | * caller holds non-exclusive termios_rwsem | |
6d76bd26 PH |
1163 | * |
1164 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1165 | */ |
4edf1827 | 1166 | |
4b293492 | 1167 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1168 | { |
57c94121 JS |
1169 | struct n_tty_data *ldata = tty->disc_data; |
1170 | ||
1da177e4 LT |
1171 | if (I_IGNBRK(tty)) |
1172 | return; | |
1173 | if (I_BRKINT(tty)) { | |
8c985d18 | 1174 | isig(SIGINT, tty); |
1da177e4 LT |
1175 | return; |
1176 | } | |
1177 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1178 | put_tty_queue('\377', ldata); |
1179 | put_tty_queue('\0', ldata); | |
1da177e4 | 1180 | } |
57c94121 | 1181 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1182 | } |
1183 | ||
1184 | /** | |
1185 | * n_tty_receive_overrun - handle overrun reporting | |
1186 | * @tty: terminal | |
1187 | * | |
1188 | * Data arrived faster than we could process it. While the tty | |
1189 | * driver has flagged this the bits that were missed are gone | |
1190 | * forever. | |
1191 | * | |
1192 | * Called from the receive_buf path so single threaded. Does not | |
1193 | * need locking as num_overrun and overrun_time are function | |
1194 | * private. | |
1195 | */ | |
4edf1827 | 1196 | |
4b293492 | 1197 | static void n_tty_receive_overrun(struct tty_struct *tty) |
1da177e4 | 1198 | { |
53c5ee2c | 1199 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1200 | |
53c5ee2c JS |
1201 | ldata->num_overrun++; |
1202 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1203 | time_after(ldata->overrun_time, jiffies)) { | |
339f36ba | 1204 | tty_warn(tty, "%d input overrun(s)\n", ldata->num_overrun); |
53c5ee2c JS |
1205 | ldata->overrun_time = jiffies; |
1206 | ldata->num_overrun = 0; | |
1da177e4 LT |
1207 | } |
1208 | } | |
1209 | ||
1210 | /** | |
1211 | * n_tty_receive_parity_error - error notifier | |
1212 | * @tty: terminal device | |
1213 | * @c: character | |
1214 | * | |
1215 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1216 | * the error case if necessary. |
1217 | * | |
1218 | * n_tty_receive_buf()/producer path: | |
1219 | * caller holds non-exclusive termios_rwsem | |
1da177e4 | 1220 | */ |
4b293492 | 1221 | static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1222 | { |
57c94121 JS |
1223 | struct n_tty_data *ldata = tty->disc_data; |
1224 | ||
66528f90 PH |
1225 | if (I_INPCK(tty)) { |
1226 | if (I_IGNPAR(tty)) | |
1227 | return; | |
1228 | if (I_PARMRK(tty)) { | |
1229 | put_tty_queue('\377', ldata); | |
1230 | put_tty_queue('\0', ldata); | |
1231 | put_tty_queue(c, ldata); | |
1232 | } else | |
1233 | put_tty_queue('\0', ldata); | |
1234 | } else | |
57c94121 | 1235 | put_tty_queue(c, ldata); |
1da177e4 LT |
1236 | } |
1237 | ||
b0ac50be PH |
1238 | static void |
1239 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1240 | { | |
d2b6f447 | 1241 | isig(signal, tty); |
b0ac50be PH |
1242 | if (I_IXON(tty)) |
1243 | start_tty(tty); | |
1244 | if (L_ECHO(tty)) { | |
1245 | echo_char(c, tty); | |
1246 | commit_echoes(tty); | |
e2613be5 PH |
1247 | } else |
1248 | process_echoes(tty); | |
b0ac50be PH |
1249 | return; |
1250 | } | |
1251 | ||
1da177e4 LT |
1252 | /** |
1253 | * n_tty_receive_char - perform processing | |
1254 | * @tty: terminal device | |
1255 | * @c: character | |
1256 | * | |
1257 | * Process an individual character of input received from the driver. | |
4edf1827 | 1258 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1259 | * driver above. |
6d76bd26 PH |
1260 | * |
1261 | * n_tty_receive_buf()/producer path: | |
1262 | * caller holds non-exclusive termios_rwsem | |
1263 | * publishes canon_head if canonical mode is active | |
e60d27c4 PH |
1264 | * |
1265 | * Returns 1 if LNEXT was received, else returns 0 | |
1da177e4 LT |
1266 | */ |
1267 | ||
e60d27c4 | 1268 | static int |
4b1f79c2 | 1269 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) |
1da177e4 | 1270 | { |
53c5ee2c | 1271 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1272 | |
1da177e4 LT |
1273 | if (I_IXON(tty)) { |
1274 | if (c == START_CHAR(tty)) { | |
1275 | start_tty(tty); | |
e2613be5 | 1276 | process_echoes(tty); |
e60d27c4 | 1277 | return 0; |
1da177e4 LT |
1278 | } |
1279 | if (c == STOP_CHAR(tty)) { | |
1280 | stop_tty(tty); | |
e60d27c4 | 1281 | return 0; |
1da177e4 LT |
1282 | } |
1283 | } | |
575537b3 | 1284 | |
1da177e4 | 1285 | if (L_ISIG(tty)) { |
b0ac50be PH |
1286 | if (c == INTR_CHAR(tty)) { |
1287 | n_tty_receive_signal_char(tty, SIGINT, c); | |
e60d27c4 | 1288 | return 0; |
b0ac50be PH |
1289 | } else if (c == QUIT_CHAR(tty)) { |
1290 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
e60d27c4 | 1291 | return 0; |
b0ac50be PH |
1292 | } else if (c == SUSP_CHAR(tty)) { |
1293 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
e60d27c4 | 1294 | return 0; |
1da177e4 LT |
1295 | } |
1296 | } | |
575537b3 | 1297 | |
855df3c0 PH |
1298 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1299 | start_tty(tty); | |
1300 | process_echoes(tty); | |
1301 | } | |
1302 | ||
575537b3 JP |
1303 | if (c == '\r') { |
1304 | if (I_IGNCR(tty)) | |
e60d27c4 | 1305 | return 0; |
575537b3 JP |
1306 | if (I_ICRNL(tty)) |
1307 | c = '\n'; | |
1308 | } else if (c == '\n' && I_INLCR(tty)) | |
1309 | c = '\r'; | |
1310 | ||
53c5ee2c | 1311 | if (ldata->icanon) { |
1da177e4 LT |
1312 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1313 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1314 | eraser(c, tty); | |
17bd7907 | 1315 | commit_echoes(tty); |
e60d27c4 | 1316 | return 0; |
1da177e4 LT |
1317 | } |
1318 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1319 | ldata->lnext = 1; |
1da177e4 | 1320 | if (L_ECHO(tty)) { |
57c94121 | 1321 | finish_erasing(ldata); |
1da177e4 | 1322 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1323 | echo_char_raw('^', ldata); |
1324 | echo_char_raw('\b', ldata); | |
17bd7907 | 1325 | commit_echoes(tty); |
1da177e4 LT |
1326 | } |
1327 | } | |
e60d27c4 | 1328 | return 1; |
1da177e4 | 1329 | } |
e60d27c4 | 1330 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { |
bc5a5e3f | 1331 | size_t tail = ldata->canon_head; |
1da177e4 | 1332 | |
57c94121 | 1333 | finish_erasing(ldata); |
1da177e4 | 1334 | echo_char(c, tty); |
57c94121 | 1335 | echo_char_raw('\n', ldata); |
3d63b7e4 | 1336 | while (MASK(tail) != MASK(ldata->read_head)) { |
bc5a5e3f PH |
1337 | echo_char(read_buf(ldata, tail), tty); |
1338 | tail++; | |
1da177e4 | 1339 | } |
17bd7907 | 1340 | commit_echoes(tty); |
e60d27c4 | 1341 | return 0; |
1da177e4 LT |
1342 | } |
1343 | if (c == '\n') { | |
acc71bba | 1344 | if (L_ECHO(tty) || L_ECHONL(tty)) { |
57c94121 | 1345 | echo_char_raw('\n', ldata); |
17bd7907 | 1346 | commit_echoes(tty); |
1da177e4 LT |
1347 | } |
1348 | goto handle_newline; | |
1349 | } | |
1350 | if (c == EOF_CHAR(tty)) { | |
1da177e4 LT |
1351 | c = __DISABLED_CHAR; |
1352 | goto handle_newline; | |
1353 | } | |
1354 | if ((c == EOL_CHAR(tty)) || | |
1355 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1356 | /* | |
1357 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1358 | */ | |
1359 | if (L_ECHO(tty)) { | |
1da177e4 | 1360 | /* Record the column of first canon char. */ |
ba2e68ac | 1361 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1362 | echo_set_canon_col(ldata); |
1da177e4 | 1363 | echo_char(c, tty); |
17bd7907 | 1364 | commit_echoes(tty); |
1da177e4 LT |
1365 | } |
1366 | /* | |
1367 | * XXX does PARMRK doubling happen for | |
1368 | * EOL_CHAR and EOL2_CHAR? | |
1369 | */ | |
001ba923 | 1370 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) |
57c94121 | 1371 | put_tty_queue(c, ldata); |
1da177e4 | 1372 | |
4edf1827 | 1373 | handle_newline: |
bc5a5e3f | 1374 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1375 | put_tty_queue(c, ldata); |
70aca71f | 1376 | smp_store_release(&ldata->canon_head, ldata->read_head); |
1da177e4 | 1377 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
a9a08845 | 1378 | wake_up_interruptible_poll(&tty->read_wait, EPOLLIN); |
e60d27c4 | 1379 | return 0; |
1da177e4 LT |
1380 | } |
1381 | } | |
4edf1827 | 1382 | |
acc71bba | 1383 | if (L_ECHO(tty)) { |
57c94121 | 1384 | finish_erasing(ldata); |
1da177e4 | 1385 | if (c == '\n') |
57c94121 | 1386 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1387 | else { |
1388 | /* Record the column of first canon char. */ | |
ba2e68ac | 1389 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1390 | echo_set_canon_col(ldata); |
1da177e4 LT |
1391 | echo_char(c, tty); |
1392 | } | |
17bd7907 | 1393 | commit_echoes(tty); |
1da177e4 LT |
1394 | } |
1395 | ||
001ba923 PH |
1396 | /* PARMRK doubling check */ |
1397 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
57c94121 | 1398 | put_tty_queue(c, ldata); |
1da177e4 | 1399 | |
57c94121 | 1400 | put_tty_queue(c, ldata); |
e60d27c4 | 1401 | return 0; |
4edf1827 | 1402 | } |
1da177e4 | 1403 | |
e60d27c4 PH |
1404 | static inline void |
1405 | n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) | |
4b1f79c2 PH |
1406 | { |
1407 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1408 | |
e60d27c4 PH |
1409 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1410 | start_tty(tty); | |
1411 | process_echoes(tty); | |
1412 | } | |
1413 | if (L_ECHO(tty)) { | |
1414 | finish_erasing(ldata); | |
1415 | /* Record the column of first canon char. */ | |
1416 | if (ldata->canon_head == ldata->read_head) | |
1417 | echo_set_canon_col(ldata); | |
1418 | echo_char(c, tty); | |
1419 | commit_echoes(tty); | |
4b1f79c2 | 1420 | } |
001ba923 PH |
1421 | /* PARMRK doubling check */ |
1422 | if (c == (unsigned char) '\377' && I_PARMRK(tty)) | |
e60d27c4 PH |
1423 | put_tty_queue(c, ldata); |
1424 | put_tty_queue(c, ldata); | |
1425 | } | |
4b1f79c2 | 1426 | |
eb3e4668 | 1427 | static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
e60d27c4 PH |
1428 | { |
1429 | n_tty_receive_char_inline(tty, c); | |
4b1f79c2 PH |
1430 | } |
1431 | ||
7de971b0 PH |
1432 | static inline void |
1433 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1434 | { | |
1435 | struct n_tty_data *ldata = tty->disc_data; | |
1436 | ||
e60d27c4 PH |
1437 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1438 | start_tty(tty); | |
1439 | process_echoes(tty); | |
7de971b0 | 1440 | } |
e60d27c4 PH |
1441 | if (L_ECHO(tty)) { |
1442 | finish_erasing(ldata); | |
1443 | /* Record the column of first canon char. */ | |
1444 | if (ldata->canon_head == ldata->read_head) | |
1445 | echo_set_canon_col(ldata); | |
1446 | echo_char(c, tty); | |
1447 | commit_echoes(tty); | |
1448 | } | |
1449 | put_tty_queue(c, ldata); | |
7de971b0 PH |
1450 | } |
1451 | ||
8dc4b25d | 1452 | static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) |
ad0cc7ba PH |
1453 | { |
1454 | if (I_ISTRIP(tty)) | |
1455 | c &= 0x7f; | |
1456 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1457 | c = tolower(c); | |
1458 | ||
1459 | if (I_IXON(tty)) { | |
1460 | if (c == STOP_CHAR(tty)) | |
1461 | stop_tty(tty); | |
1462 | else if (c == START_CHAR(tty) || | |
1463 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1464 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1465 | c != SUSP_CHAR(tty))) { | |
1466 | start_tty(tty); | |
1467 | process_echoes(tty); | |
1468 | } | |
1469 | } | |
1470 | } | |
1471 | ||
d2f8d7ab PH |
1472 | static void |
1473 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1474 | { | |
d2f8d7ab PH |
1475 | switch (flag) { |
1476 | case TTY_BREAK: | |
1477 | n_tty_receive_break(tty); | |
1478 | break; | |
1479 | case TTY_PARITY: | |
1480 | case TTY_FRAME: | |
1481 | n_tty_receive_parity_error(tty, c); | |
1482 | break; | |
1483 | case TTY_OVERRUN: | |
1484 | n_tty_receive_overrun(tty); | |
1485 | break; | |
1486 | default: | |
339f36ba | 1487 | tty_err(tty, "unknown flag %d\n", flag); |
d2f8d7ab PH |
1488 | break; |
1489 | } | |
1490 | } | |
1491 | ||
e60d27c4 PH |
1492 | static void |
1493 | n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) | |
1494 | { | |
1495 | struct n_tty_data *ldata = tty->disc_data; | |
1496 | ||
1497 | ldata->lnext = 0; | |
1498 | if (likely(flag == TTY_NORMAL)) { | |
1499 | if (I_ISTRIP(tty)) | |
1500 | c &= 0x7f; | |
1501 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1502 | c = tolower(c); | |
1503 | n_tty_receive_char(tty, c); | |
1504 | } else | |
1505 | n_tty_receive_char_flagged(tty, c, flag); | |
1506 | } | |
1507 | ||
4a23a4df PH |
1508 | static void |
1509 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1510 | char *fp, int count) | |
1511 | { | |
1512 | struct n_tty_data *ldata = tty->disc_data; | |
1513 | size_t n, head; | |
1514 | ||
1515 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1516 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1517 | memcpy(read_buf_addr(ldata, head), cp, n); |
1518 | ldata->read_head += n; | |
1519 | cp += n; | |
1520 | count -= n; | |
1521 | ||
1522 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
70aca71f | 1523 | n = min_t(size_t, count, N_TTY_BUF_SIZE - head); |
4a23a4df PH |
1524 | memcpy(read_buf_addr(ldata, head), cp, n); |
1525 | ldata->read_head += n; | |
1526 | } | |
1527 | ||
554117bd PH |
1528 | static void |
1529 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1530 | char *fp, int count) | |
1531 | { | |
1532 | struct n_tty_data *ldata = tty->disc_data; | |
1533 | char flag = TTY_NORMAL; | |
1534 | ||
1535 | while (count--) { | |
1536 | if (fp) | |
1537 | flag = *fp++; | |
1538 | if (likely(flag == TTY_NORMAL)) | |
1539 | put_tty_queue(*cp++, ldata); | |
1540 | else | |
1541 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1542 | } | |
1543 | } | |
1544 | ||
ad0cc7ba PH |
1545 | static void |
1546 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1547 | char *fp, int count) | |
1548 | { | |
1549 | char flag = TTY_NORMAL; | |
1550 | ||
1551 | while (count--) { | |
1552 | if (fp) | |
1553 | flag = *fp++; | |
1554 | if (likely(flag == TTY_NORMAL)) | |
1555 | n_tty_receive_char_closing(tty, *cp++); | |
ad0cc7ba PH |
1556 | } |
1557 | } | |
1558 | ||
7d88d637 PH |
1559 | static void |
1560 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1561 | char *fp, int count) |
1562 | { | |
1563 | struct n_tty_data *ldata = tty->disc_data; | |
1564 | char flag = TTY_NORMAL; | |
1565 | ||
1566 | while (count--) { | |
1567 | if (fp) | |
1568 | flag = *fp++; | |
1569 | if (likely(flag == TTY_NORMAL)) { | |
1570 | unsigned char c = *cp++; | |
1571 | ||
1572 | if (I_ISTRIP(tty)) | |
1573 | c &= 0x7f; | |
1574 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1575 | c = tolower(c); | |
1576 | if (L_EXTPROC(tty)) { | |
1577 | put_tty_queue(c, ldata); | |
1578 | continue; | |
1579 | } | |
e60d27c4 PH |
1580 | if (!test_bit(c, ldata->char_map)) |
1581 | n_tty_receive_char_inline(tty, c); | |
1582 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1583 | if (fp) | |
1584 | flag = *fp++; | |
1585 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1586 | count--; | |
1587 | } | |
6baad008 PH |
1588 | } else |
1589 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1590 | } | |
1591 | } | |
1592 | ||
1593 | static void | |
1594 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1595 | char *fp, int count) | |
7d88d637 | 1596 | { |
e60d27c4 | 1597 | struct n_tty_data *ldata = tty->disc_data; |
7d88d637 PH |
1598 | char flag = TTY_NORMAL; |
1599 | ||
1600 | while (count--) { | |
1601 | if (fp) | |
1602 | flag = *fp++; | |
e60d27c4 PH |
1603 | if (likely(flag == TTY_NORMAL)) { |
1604 | unsigned char c = *cp++; | |
1605 | ||
1606 | if (!test_bit(c, ldata->char_map)) | |
1607 | n_tty_receive_char_fast(tty, c); | |
1608 | else if (n_tty_receive_char_special(tty, c) && count) { | |
1609 | if (fp) | |
1610 | flag = *fp++; | |
1611 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1612 | count--; | |
1613 | } | |
1614 | } else | |
7d88d637 PH |
1615 | n_tty_receive_char_flagged(tty, *cp++, flag); |
1616 | } | |
1617 | } | |
1618 | ||
24a89d1c PH |
1619 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1620 | char *fp, int count) | |
1da177e4 | 1621 | { |
53c5ee2c | 1622 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1623 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1624 | |
4a23a4df PH |
1625 | if (ldata->real_raw) |
1626 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1627 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1628 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1629 | else if (tty->closing && !L_EXTPROC(tty)) |
1630 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1631 | else { |
e60d27c4 PH |
1632 | if (ldata->lnext) { |
1633 | char flag = TTY_NORMAL; | |
1634 | ||
1635 | if (fp) | |
1636 | flag = *fp++; | |
1637 | n_tty_receive_char_lnext(tty, *cp++, flag); | |
1638 | count--; | |
1639 | } | |
1640 | ||
7de971b0 | 1641 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1642 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1643 | else | |
1644 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1645 | |
1646 | flush_echoes(tty); | |
f34d7a5b AC |
1647 | if (tty->ops->flush_chars) |
1648 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1649 | } |
1650 | ||
70aca71f PH |
1651 | if (ldata->icanon && !L_EXTPROC(tty)) |
1652 | return; | |
1653 | ||
1654 | /* publish read_head to consumer */ | |
1655 | smp_store_release(&ldata->commit_head, ldata->read_head); | |
1656 | ||
33d71363 | 1657 | if (read_cnt(ldata)) { |
1da177e4 | 1658 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
a9a08845 | 1659 | wake_up_interruptible_poll(&tty->read_wait, EPOLLIN); |
1da177e4 | 1660 | } |
1da177e4 LT |
1661 | } |
1662 | ||
fb5ef9e7 PH |
1663 | /** |
1664 | * n_tty_receive_buf_common - process input | |
1665 | * @tty: device to receive input | |
1666 | * @cp: input chars | |
1667 | * @fp: flags for each char (if NULL, all chars are TTY_NORMAL) | |
1668 | * @count: number of input chars in @cp | |
1669 | * | |
1670 | * Called by the terminal driver when a block of characters has | |
1671 | * been received. This function must be called from soft contexts | |
1672 | * not from interrupt context. The driver is responsible for making | |
1673 | * calls one at a time and in order (or using flush_to_ldisc) | |
1674 | * | |
1675 | * Returns the # of input chars from @cp which were processed. | |
1676 | * | |
1677 | * In canonical mode, the maximum line length is 4096 chars (including | |
1678 | * the line termination char); lines longer than 4096 chars are | |
1679 | * truncated. After 4095 chars, input data is still processed but | |
1680 | * not stored. Overflow processing ensures the tty can always | |
1681 | * receive more input until at least one line can be read. | |
1682 | * | |
1683 | * In non-canonical mode, the read buffer will only accept 4095 chars; | |
1684 | * this provides the necessary space for a newline char if the input | |
1685 | * mode is switched to canonical. | |
1686 | * | |
1687 | * Note it is possible for the read buffer to _contain_ 4096 chars | |
1688 | * in non-canonical mode: the read buffer could already contain the | |
1689 | * maximum canon line of 4096 chars when the mode is switched to | |
1690 | * non-canonical. | |
1691 | * | |
1692 | * n_tty_receive_buf()/producer path: | |
1693 | * claims non-exclusive termios_rwsem | |
1694 | * publishes commit_head or canon_head | |
1695 | */ | |
5c32d123 PH |
1696 | static int |
1697 | n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, | |
1698 | char *fp, int count, int flow) | |
24a89d1c PH |
1699 | { |
1700 | struct n_tty_data *ldata = tty->disc_data; | |
fb5ef9e7 | 1701 | int room, n, rcvd = 0, overflow; |
24a89d1c | 1702 | |
9356b535 PH |
1703 | down_read(&tty->termios_rwsem); |
1704 | ||
19e2ad6a | 1705 | while (1) { |
70aca71f | 1706 | /* |
06c49f9f PH |
1707 | * When PARMRK is set, each input char may take up to 3 chars |
1708 | * in the read buf; reduce the buffer space avail by 3x | |
70aca71f PH |
1709 | * |
1710 | * If we are doing input canonicalization, and there are no | |
1711 | * pending newlines, let characters through without limit, so | |
1712 | * that erase characters will be handled. Other excess | |
1713 | * characters will be beeped. | |
1714 | * | |
1715 | * paired with store in *_copy_from_read_buf() -- guarantees | |
1716 | * the consumer has loaded the data in read_buf up to the new | |
1717 | * read_tail (so this producer will not overwrite unread data) | |
1718 | */ | |
1719 | size_t tail = smp_load_acquire(&ldata->read_tail); | |
70aca71f | 1720 | |
fb5ef9e7 | 1721 | room = N_TTY_BUF_SIZE - (ldata->read_head - tail); |
70aca71f | 1722 | if (I_PARMRK(tty)) |
fb5ef9e7 PH |
1723 | room = (room + 2) / 3; |
1724 | room--; | |
1725 | if (room <= 0) { | |
1726 | overflow = ldata->icanon && ldata->canon_head == tail; | |
1727 | if (overflow && room < 0) | |
1728 | ldata->read_head--; | |
1729 | room = overflow; | |
1730 | ldata->no_room = flow && !room; | |
1731 | } else | |
1732 | overflow = 0; | |
70aca71f | 1733 | |
19e2ad6a | 1734 | n = min(count, room); |
fb5ef9e7 | 1735 | if (!n) |
19e2ad6a | 1736 | break; |
fb5ef9e7 PH |
1737 | |
1738 | /* ignore parity errors if handling overflow */ | |
1739 | if (!overflow || !fp || *fp != TTY_PARITY) | |
1740 | __receive_buf(tty, cp, fp, n); | |
1741 | ||
19e2ad6a PH |
1742 | cp += n; |
1743 | if (fp) | |
1744 | fp += n; | |
1745 | count -= n; | |
1746 | rcvd += n; | |
4a23a4df | 1747 | } |
24a89d1c | 1748 | |
19e2ad6a | 1749 | tty->receive_room = room; |
fb5ef9e7 PH |
1750 | |
1751 | /* Unthrottle if handling overflow on pty */ | |
1752 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { | |
1753 | if (overflow) { | |
1754 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1755 | tty_unthrottle_safe(tty); | |
1756 | __tty_set_flow_change(tty, 0); | |
1757 | } | |
1758 | } else | |
1759 | n_tty_check_throttle(tty); | |
1760 | ||
9356b535 PH |
1761 | up_read(&tty->termios_rwsem); |
1762 | ||
19e2ad6a | 1763 | return rcvd; |
24a89d1c PH |
1764 | } |
1765 | ||
5c32d123 PH |
1766 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1767 | char *fp, int count) | |
1768 | { | |
1769 | n_tty_receive_buf_common(tty, cp, fp, count, 0); | |
1770 | } | |
1771 | ||
1772 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1773 | char *fp, int count) | |
1774 | { | |
1775 | return n_tty_receive_buf_common(tty, cp, fp, count, 1); | |
1776 | } | |
1777 | ||
1da177e4 LT |
1778 | /** |
1779 | * n_tty_set_termios - termios data changed | |
1780 | * @tty: terminal | |
1781 | * @old: previous data | |
1782 | * | |
1783 | * Called by the tty layer when the user changes termios flags so | |
1784 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1785 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1786 | * guaranteed that this function will not be re-entered or in progress |
1787 | * when the ldisc is closed. | |
17b82060 | 1788 | * |
6a1c0680 | 1789 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1790 | */ |
4edf1827 AC |
1791 | |
1792 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1793 | { |
53c5ee2c | 1794 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1795 | |
966031f3 | 1796 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & (ICANON | EXTPROC)) { |
3fe780b3 | 1797 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1798 | ldata->line_start = ldata->read_tail; |
1799 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1800 | ldata->canon_head = ldata->read_tail; | |
1801 | ldata->push = 0; | |
1802 | } else { | |
1803 | set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), | |
1804 | ldata->read_flags); | |
1805 | ldata->canon_head = ldata->read_head; | |
1806 | ldata->push = 1; | |
1807 | } | |
70aca71f | 1808 | ldata->commit_head = ldata->read_head; |
53c5ee2c | 1809 | ldata->erasing = 0; |
6f9b028a | 1810 | ldata->lnext = 0; |
47afa7a5 AC |
1811 | } |
1812 | ||
53c5ee2c | 1813 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1814 | |
1da177e4 LT |
1815 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1816 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1817 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1818 | I_PARMRK(tty)) { | |
1bb9d562 | 1819 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1820 | |
1821 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1822 | set_bit('\r', ldata->char_map); |
1da177e4 | 1823 | if (I_INLCR(tty)) |
1bb9d562 | 1824 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1825 | |
1826 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1827 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1828 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1829 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1830 | set_bit('\n', ldata->char_map); | |
1831 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1832 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1833 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1834 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1835 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1836 | if (L_ECHO(tty)) |
1837 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1838 | ldata->char_map); |
1da177e4 LT |
1839 | } |
1840 | } | |
1841 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1842 | set_bit(START_CHAR(tty), ldata->char_map); |
1843 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1844 | } |
1845 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1846 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1847 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1848 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1849 | } |
1bb9d562 | 1850 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1851 | ldata->raw = 0; |
1852 | ldata->real_raw = 0; | |
1da177e4 | 1853 | } else { |
53c5ee2c | 1854 | ldata->raw = 1; |
1da177e4 LT |
1855 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1856 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1857 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1858 | ldata->real_raw = 1; |
1da177e4 | 1859 | else |
53c5ee2c | 1860 | ldata->real_raw = 0; |
1da177e4 | 1861 | } |
dab73b4e WY |
1862 | /* |
1863 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1864 | * been stopped by STOP_CHAR(tty) before it. | |
1865 | */ | |
e2613be5 | 1866 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { |
dab73b4e | 1867 | start_tty(tty); |
e2613be5 PH |
1868 | process_echoes(tty); |
1869 | } | |
dab73b4e | 1870 | |
f34d7a5b | 1871 | /* The termios change make the tty ready for I/O */ |
e81107d4 KT |
1872 | wake_up_interruptible(&tty->write_wait); |
1873 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1874 | } |
1875 | ||
1876 | /** | |
1877 | * n_tty_close - close the ldisc for this tty | |
1878 | * @tty: device | |
1879 | * | |
4edf1827 AC |
1880 | * Called from the terminal layer when this line discipline is |
1881 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1882 | * discipline change. The function will not be called while other |
1883 | * ldisc methods are in progress. | |
1884 | */ | |
4edf1827 | 1885 | |
1da177e4 LT |
1886 | static void n_tty_close(struct tty_struct *tty) |
1887 | { | |
70ece7a7 JS |
1888 | struct n_tty_data *ldata = tty->disc_data; |
1889 | ||
79901317 PH |
1890 | if (tty->link) |
1891 | n_tty_packet_mode_flush(tty); | |
1892 | ||
20bafb3d | 1893 | vfree(ldata); |
70ece7a7 | 1894 | tty->disc_data = NULL; |
1da177e4 LT |
1895 | } |
1896 | ||
1897 | /** | |
1898 | * n_tty_open - open an ldisc | |
1899 | * @tty: terminal to open | |
1900 | * | |
4edf1827 | 1901 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1902 | * terminal device. Can sleep. Called serialized so that no |
1903 | * other events will occur in parallel. No further open will occur | |
1904 | * until a close. | |
1905 | */ | |
1906 | ||
1907 | static int n_tty_open(struct tty_struct *tty) | |
1908 | { | |
70ece7a7 JS |
1909 | struct n_tty_data *ldata; |
1910 | ||
20bafb3d | 1911 | /* Currently a malloc failure here can panic */ |
ebec3f8f | 1912 | ldata = vzalloc(sizeof(*ldata)); |
70ece7a7 | 1913 | if (!ldata) |
ebec3f8f | 1914 | return -ENOMEM; |
70ece7a7 | 1915 | |
53c5ee2c | 1916 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1917 | mutex_init(&ldata->atomic_read_lock); |
1918 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1919 | |
70ece7a7 | 1920 | tty->disc_data = ldata; |
1da177e4 | 1921 | tty->closing = 0; |
b66f4fa5 PH |
1922 | /* indicate buffer work may resume */ |
1923 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1924 | n_tty_set_termios(tty, NULL); | |
1925 | tty_unthrottle(tty); | |
1da177e4 LT |
1926 | return 0; |
1927 | } | |
1928 | ||
eafbe67f | 1929 | static inline int input_available_p(struct tty_struct *tty, int poll) |
1da177e4 | 1930 | { |
53c5ee2c | 1931 | struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1932 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1933 | |
25e8d0ed PH |
1934 | if (ldata->icanon && !L_EXTPROC(tty)) |
1935 | return ldata->canon_head != ldata->read_tail; | |
1936 | else | |
70aca71f | 1937 | return ldata->commit_head - ldata->read_tail >= amt; |
1da177e4 LT |
1938 | } |
1939 | ||
1940 | /** | |
bbd20759 | 1941 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1942 | * @tty: terminal device |
1943 | * @b: user data | |
1944 | * @nr: size of data | |
1945 | * | |
11a96d18 | 1946 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1947 | * ICANON is off; it copies characters straight from the tty queue to |
1948 | * user space directly. It can be profitably called twice; once to | |
1949 | * drain the space from the tail pointer to the (physical) end of the | |
1950 | * buffer, and once to drain the space from the (physical) beginning of | |
1951 | * the buffer to head pointer. | |
1952 | * | |
bddc7152 | 1953 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1954 | * |
6d76bd26 PH |
1955 | * n_tty_read()/consumer path: |
1956 | * caller holds non-exclusive termios_rwsem | |
1957 | * read_tail published | |
1da177e4 | 1958 | */ |
4edf1827 | 1959 | |
33f0f88f | 1960 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1961 | unsigned char __user **b, |
1962 | size_t *nr) | |
1963 | ||
1964 | { | |
53c5ee2c | 1965 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1966 | int retval; |
1967 | size_t n; | |
3fa10cc8 | 1968 | bool is_eof; |
70aca71f | 1969 | size_t head = smp_load_acquire(&ldata->commit_head); |
bc5a5e3f | 1970 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1971 | |
1972 | retval = 0; | |
70aca71f | 1973 | n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail); |
1da177e4 | 1974 | n = min(*nr, n); |
1da177e4 | 1975 | if (n) { |
b97b3d9f | 1976 | unsigned char *from = read_buf_addr(ldata, tail); |
e661cf70 | 1977 | retval = copy_to_user(*b, from, n); |
1da177e4 | 1978 | n -= retval; |
e661cf70 | 1979 | is_eof = n == 1 && *from == EOF_CHAR(tty); |
309426ae | 1980 | tty_audit_add_data(tty, from, n); |
b97b3d9f | 1981 | zero_buffer(tty, from, n); |
70aca71f | 1982 | smp_store_release(&ldata->read_tail, ldata->read_tail + n); |
26df6d13 | 1983 | /* Turn single EOF into zero-length read */ |
70aca71f PH |
1984 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && |
1985 | (head == ldata->read_tail)) | |
3fa10cc8 | 1986 | n = 0; |
1da177e4 LT |
1987 | *b += n; |
1988 | *nr -= n; | |
1989 | } | |
1990 | return retval; | |
1991 | } | |
1992 | ||
88bb0de3 | 1993 | /** |
32f13521 | 1994 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1995 | * @tty: terminal device |
1996 | * @b: user data | |
1997 | * @nr: size of data | |
1998 | * | |
1999 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
2000 | * it copies one line of input up to and including the line-delimiting |
2001 | * character into the user-space buffer. | |
88bb0de3 | 2002 | * |
4d0ed182 PH |
2003 | * NB: When termios is changed from non-canonical to canonical mode and |
2004 | * the read buffer contains data, n_tty_set_termios() simulates an EOF | |
2005 | * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. | |
2006 | * This causes data already processed as input to be immediately available | |
2007 | * as input although a newline has not been received. | |
2008 | * | |
88bb0de3 | 2009 | * Called under the atomic_read_lock mutex |
6d76bd26 PH |
2010 | * |
2011 | * n_tty_read()/consumer path: | |
2012 | * caller holds non-exclusive termios_rwsem | |
2013 | * read_tail published | |
88bb0de3 PH |
2014 | */ |
2015 | ||
32f13521 PH |
2016 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
2017 | unsigned char __user **b, | |
2018 | size_t *nr) | |
88bb0de3 PH |
2019 | { |
2020 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 2021 | size_t n, size, more, c; |
bc5a5e3f PH |
2022 | size_t eol; |
2023 | size_t tail; | |
2024 | int ret, found = 0; | |
88bb0de3 PH |
2025 | |
2026 | /* N.B. avoid overrun if nr == 0 */ | |
ac8f3bf8 | 2027 | if (!*nr) |
32f13521 | 2028 | return 0; |
88bb0de3 | 2029 | |
ac8f3bf8 PH |
2030 | n = min(*nr + 1, smp_load_acquire(&ldata->canon_head) - ldata->read_tail); |
2031 | ||
bc5a5e3f | 2032 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
2033 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
2034 | ||
bc5a5e3f | 2035 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2036 | __func__, *nr, tail, n, size); |
2037 | ||
2038 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2039 | more = n - (size - tail); | |
2040 | if (eol == N_TTY_BUF_SIZE && more) { | |
2041 | /* scan wrapped without finding set bit */ | |
2042 | eol = find_next_bit(ldata->read_flags, more, 0); | |
b985e9e3 PH |
2043 | found = eol != more; |
2044 | } else | |
2045 | found = eol != size; | |
32f13521 | 2046 | |
c77569d2 | 2047 | n = eol - tail; |
da555db6 MT |
2048 | if (n > N_TTY_BUF_SIZE) |
2049 | n += N_TTY_BUF_SIZE; | |
ac8f3bf8 | 2050 | c = n + found; |
32f13521 | 2051 | |
ac8f3bf8 PH |
2052 | if (!found || read_buf(ldata, eol) != __DISABLED_CHAR) { |
2053 | c = min(*nr, c); | |
2054 | n = c; | |
40d5e090 | 2055 | } |
32f13521 | 2056 | |
679e7c29 PH |
2057 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu tail:%zu more:%zu\n", |
2058 | __func__, eol, found, n, c, tail, more); | |
32f13521 | 2059 | |
679e7c29 | 2060 | ret = tty_copy_to_user(tty, *b, tail, n); |
32f13521 PH |
2061 | if (ret) |
2062 | return -EFAULT; | |
2063 | *b += n; | |
2064 | *nr -= n; | |
2065 | ||
a73d3d69 | 2066 | if (found) |
6d76bd26 | 2067 | clear_bit(eol, ldata->read_flags); |
70aca71f | 2068 | smp_store_release(&ldata->read_tail, ldata->read_tail + c); |
88bb0de3 | 2069 | |
40d5e090 | 2070 | if (found) { |
4d0ed182 PH |
2071 | if (!ldata->push) |
2072 | ldata->line_start = ldata->read_tail; | |
2073 | else | |
2074 | ldata->push = 0; | |
b50819f4 | 2075 | tty_audit_push(); |
40d5e090 | 2076 | } |
ac8f3bf8 | 2077 | return 0; |
88bb0de3 PH |
2078 | } |
2079 | ||
cc4191dc | 2080 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2081 | size_t, loff_t *); |
1da177e4 LT |
2082 | |
2083 | /** | |
2084 | * job_control - check job control | |
2085 | * @tty: tty | |
2086 | * @file: file handle | |
2087 | * | |
2088 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2089 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2090 | * error code if action should be taken. |
04f378b1 | 2091 | * |
01a5e440 PH |
2092 | * Locking: redirected write test is safe |
2093 | * current->signal->tty check is safe | |
2094 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2095 | */ |
4edf1827 | 2096 | |
1da177e4 LT |
2097 | static int job_control(struct tty_struct *tty, struct file *file) |
2098 | { | |
2099 | /* Job control check -- must be done at start and after | |
2100 | every sleep (POSIX.1 7.1.1.4). */ | |
2101 | /* NOTE: not yet done after every sleep pending a thorough | |
2102 | check of the logic of this change. -- jlc */ | |
2103 | /* don't stop on /dev/console */ | |
2812d9e9 | 2104 | if (file->f_op->write == redirected_tty_write) |
01a5e440 PH |
2105 | return 0; |
2106 | ||
2812d9e9 | 2107 | return __tty_check_change(tty, SIGTTIN); |
1da177e4 | 2108 | } |
4edf1827 | 2109 | |
1da177e4 LT |
2110 | |
2111 | /** | |
11a96d18 | 2112 | * n_tty_read - read function for tty |
1da177e4 LT |
2113 | * @tty: tty device |
2114 | * @file: file object | |
2115 | * @buf: userspace buffer pointer | |
2116 | * @nr: size of I/O | |
2117 | * | |
2118 | * Perform reads for the line discipline. We are guaranteed that the | |
2119 | * line discipline will not be closed under us but we may get multiple | |
2120 | * parallel readers and must handle this ourselves. We may also get | |
2121 | * a hangup. Always called in user context, may sleep. | |
2122 | * | |
2123 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2124 | * |
2125 | * n_tty_read()/consumer path: | |
2126 | * claims non-exclusive termios_rwsem | |
2127 | * publishes read_tail | |
1da177e4 | 2128 | */ |
4edf1827 | 2129 | |
11a96d18 | 2130 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2131 | unsigned char __user *buf, size_t nr) |
2132 | { | |
53c5ee2c | 2133 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 2134 | unsigned char __user *b = buf; |
97d9e28d | 2135 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
0f40fbbc | 2136 | int c; |
1da177e4 LT |
2137 | int minimum, time; |
2138 | ssize_t retval = 0; | |
1da177e4 | 2139 | long timeout; |
04f378b1 | 2140 | int packet; |
2c5dc464 | 2141 | size_t tail; |
1da177e4 | 2142 | |
1da177e4 | 2143 | c = job_control(tty, file); |
4edf1827 | 2144 | if (c < 0) |
1da177e4 | 2145 | return c; |
4edf1827 | 2146 | |
aefceaf4 PH |
2147 | /* |
2148 | * Internal serialization of reads. | |
2149 | */ | |
2150 | if (file->f_flags & O_NONBLOCK) { | |
2151 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2152 | return -EAGAIN; | |
2153 | } else { | |
2154 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2155 | return -ERESTARTSYS; | |
2156 | } | |
2157 | ||
9356b535 PH |
2158 | down_read(&tty->termios_rwsem); |
2159 | ||
1da177e4 LT |
2160 | minimum = time = 0; |
2161 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2162 | if (!ldata->icanon) { |
1da177e4 LT |
2163 | minimum = MIN_CHAR(tty); |
2164 | if (minimum) { | |
a6e54319 | 2165 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2166 | } else { |
a6e54319 | 2167 | timeout = (HZ / 10) * TIME_CHAR(tty); |
33d71363 | 2168 | minimum = 1; |
1da177e4 LT |
2169 | } |
2170 | } | |
2171 | ||
04f378b1 | 2172 | packet = tty->packet; |
2c5dc464 | 2173 | tail = ldata->read_tail; |
1da177e4 LT |
2174 | |
2175 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2176 | while (nr) { |
2177 | /* First test for status change. */ | |
04f378b1 | 2178 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2179 | unsigned char cs; |
2180 | if (b != buf) | |
2181 | break; | |
6054c16e | 2182 | spin_lock_irq(&tty->link->ctrl_lock); |
1da177e4 LT |
2183 | cs = tty->link->ctrl_status; |
2184 | tty->link->ctrl_status = 0; | |
6054c16e | 2185 | spin_unlock_irq(&tty->link->ctrl_lock); |
eab25a5c | 2186 | if (put_user(cs, b)) { |
1da177e4 | 2187 | retval = -EFAULT; |
1da177e4 LT |
2188 | break; |
2189 | } | |
eab25a5c | 2190 | b++; |
1da177e4 LT |
2191 | nr--; |
2192 | break; | |
2193 | } | |
4edf1827 | 2194 | |
1da177e4 | 2195 | if (!input_available_p(tty, 0)) { |
52bce7f8 | 2196 | up_read(&tty->termios_rwsem); |
0f40fbbc BB |
2197 | tty_buffer_flush_work(tty->port); |
2198 | down_read(&tty->termios_rwsem); | |
2199 | if (!input_available_p(tty, 0)) { | |
2200 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
2201 | retval = -EIO; | |
2202 | break; | |
2203 | } | |
2204 | if (tty_hung_up_p(file)) | |
2205 | break; | |
28b0f8a6 TH |
2206 | /* |
2207 | * Abort readers for ttys which never actually | |
2208 | * get hung up. See __tty_hangup(). | |
2209 | */ | |
2210 | if (test_bit(TTY_HUPPING, &tty->flags)) | |
2211 | break; | |
0f40fbbc BB |
2212 | if (!timeout) |
2213 | break; | |
2214 | if (file->f_flags & O_NONBLOCK) { | |
2215 | retval = -EAGAIN; | |
2216 | break; | |
2217 | } | |
2218 | if (signal_pending(current)) { | |
2219 | retval = -ERESTARTSYS; | |
2220 | break; | |
2221 | } | |
2222 | up_read(&tty->termios_rwsem); | |
9356b535 | 2223 | |
0f40fbbc BB |
2224 | timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, |
2225 | timeout); | |
9356b535 | 2226 | |
0f40fbbc BB |
2227 | down_read(&tty->termios_rwsem); |
2228 | continue; | |
2229 | } | |
1da177e4 LT |
2230 | } |
2231 | ||
53c5ee2c | 2232 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2233 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
ac8f3bf8 | 2234 | if (retval) |
1da177e4 LT |
2235 | break; |
2236 | } else { | |
2237 | int uncopied; | |
95ea90db PH |
2238 | |
2239 | /* Deal with packet mode. */ | |
2240 | if (packet && b == buf) { | |
eab25a5c | 2241 | if (put_user(TIOCPKT_DATA, b)) { |
95ea90db | 2242 | retval = -EFAULT; |
95ea90db PH |
2243 | break; |
2244 | } | |
eab25a5c | 2245 | b++; |
95ea90db PH |
2246 | nr--; |
2247 | } | |
2248 | ||
1da177e4 LT |
2249 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2250 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2251 | if (uncopied) { | |
2252 | retval = -EFAULT; | |
2253 | break; | |
2254 | } | |
2255 | } | |
2256 | ||
6367ca72 | 2257 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2258 | |
2259 | if (b - buf >= minimum) | |
2260 | break; | |
2261 | if (time) | |
2262 | timeout = time; | |
2263 | } | |
2c5dc464 PH |
2264 | if (tail != ldata->read_tail) |
2265 | n_tty_kick_worker(tty); | |
42458f41 PH |
2266 | up_read(&tty->termios_rwsem); |
2267 | ||
1da177e4 | 2268 | remove_wait_queue(&tty->read_wait, &wait); |
aebf0453 PH |
2269 | mutex_unlock(&ldata->atomic_read_lock); |
2270 | ||
40d5e090 PH |
2271 | if (b - buf) |
2272 | retval = b - buf; | |
1da177e4 LT |
2273 | |
2274 | return retval; | |
2275 | } | |
2276 | ||
2277 | /** | |
11a96d18 | 2278 | * n_tty_write - write function for tty |
1da177e4 LT |
2279 | * @tty: tty device |
2280 | * @file: file object | |
2281 | * @buf: userspace buffer pointer | |
2282 | * @nr: size of I/O | |
2283 | * | |
a88a69c9 | 2284 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2285 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2286 | * and other such events. Since the receive code will echo characters, |
2287 | * thus calling driver write methods, the output_lock is used in | |
2288 | * the output processing functions called here as well as in the | |
2289 | * echo processing function to protect the column state and space | |
2290 | * left in the buffer. | |
1da177e4 LT |
2291 | * |
2292 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2293 | * |
2294 | * Locking: output_lock to protect column state and space left | |
2295 | * (note that the process_output*() functions take this | |
2296 | * lock themselves) | |
1da177e4 | 2297 | */ |
4edf1827 | 2298 | |
11a96d18 | 2299 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2300 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2301 | { |
2302 | const unsigned char *b = buf; | |
97d9e28d | 2303 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 LT |
2304 | int c; |
2305 | ssize_t retval = 0; | |
2306 | ||
2307 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2308 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2309 | retval = tty_check_change(tty); | |
2310 | if (retval) | |
2311 | return retval; | |
2312 | } | |
2313 | ||
9356b535 PH |
2314 | down_read(&tty->termios_rwsem); |
2315 | ||
a88a69c9 JP |
2316 | /* Write out any echoed characters that are still pending */ |
2317 | process_echoes(tty); | |
300a6204 | 2318 | |
1da177e4 LT |
2319 | add_wait_queue(&tty->write_wait, &wait); |
2320 | while (1) { | |
1da177e4 LT |
2321 | if (signal_pending(current)) { |
2322 | retval = -ERESTARTSYS; | |
2323 | break; | |
2324 | } | |
2325 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2326 | retval = -EIO; | |
2327 | break; | |
2328 | } | |
582f5590 | 2329 | if (O_OPOST(tty)) { |
1da177e4 | 2330 | while (nr > 0) { |
a88a69c9 | 2331 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2332 | if (num < 0) { |
2333 | if (num == -EAGAIN) | |
2334 | break; | |
2335 | retval = num; | |
2336 | goto break_out; | |
2337 | } | |
2338 | b += num; | |
2339 | nr -= num; | |
2340 | if (nr == 0) | |
2341 | break; | |
2342 | c = *b; | |
a88a69c9 | 2343 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2344 | break; |
2345 | b++; nr--; | |
2346 | } | |
f34d7a5b AC |
2347 | if (tty->ops->flush_chars) |
2348 | tty->ops->flush_chars(tty); | |
1da177e4 | 2349 | } else { |
4291086b PH |
2350 | struct n_tty_data *ldata = tty->disc_data; |
2351 | ||
d6afe27b | 2352 | while (nr > 0) { |
4291086b | 2353 | mutex_lock(&ldata->output_lock); |
f34d7a5b | 2354 | c = tty->ops->write(tty, b, nr); |
4291086b | 2355 | mutex_unlock(&ldata->output_lock); |
d6afe27b RZ |
2356 | if (c < 0) { |
2357 | retval = c; | |
2358 | goto break_out; | |
2359 | } | |
2360 | if (!c) | |
2361 | break; | |
2362 | b += c; | |
2363 | nr -= c; | |
1da177e4 | 2364 | } |
1da177e4 LT |
2365 | } |
2366 | if (!nr) | |
2367 | break; | |
2368 | if (file->f_flags & O_NONBLOCK) { | |
2369 | retval = -EAGAIN; | |
2370 | break; | |
2371 | } | |
9356b535 PH |
2372 | up_read(&tty->termios_rwsem); |
2373 | ||
97d9e28d | 2374 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
9356b535 PH |
2375 | |
2376 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2377 | } |
2378 | break_out: | |
1da177e4 | 2379 | remove_wait_queue(&tty->write_wait, &wait); |
87108bc9 | 2380 | if (nr && tty->fasync) |
ff8cb0fd | 2381 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
9356b535 | 2382 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2383 | return (b - buf) ? b - buf : retval; |
2384 | } | |
2385 | ||
2386 | /** | |
11a96d18 | 2387 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2388 | * @tty: terminal device |
2389 | * @file: file accessing it | |
2390 | * @wait: poll table | |
2391 | * | |
2392 | * Called when the line discipline is asked to poll() for data or | |
2393 | * for special events. This code is not serialized with respect to | |
2394 | * other events save open/close. | |
2395 | * | |
2396 | * This code must be sure never to sleep through a hangup. | |
2397 | * Called without the kernel lock held - fine | |
1da177e4 | 2398 | */ |
4edf1827 | 2399 | |
afc9a42b | 2400 | static __poll_t n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2401 | poll_table *wait) |
1da177e4 | 2402 | { |
afc9a42b | 2403 | __poll_t mask = 0; |
1da177e4 LT |
2404 | |
2405 | poll_wait(file, &tty->read_wait, wait); | |
2406 | poll_wait(file, &tty->write_wait, wait); | |
eafbe67f | 2407 | if (input_available_p(tty, 1)) |
a9a08845 | 2408 | mask |= EPOLLIN | EPOLLRDNORM; |
0f40fbbc BB |
2409 | else { |
2410 | tty_buffer_flush_work(tty->port); | |
2411 | if (input_available_p(tty, 1)) | |
a9a08845 | 2412 | mask |= EPOLLIN | EPOLLRDNORM; |
0f40fbbc | 2413 | } |
1da177e4 | 2414 | if (tty->packet && tty->link->ctrl_status) |
a9a08845 | 2415 | mask |= EPOLLPRI | EPOLLIN | EPOLLRDNORM; |
0f40fbbc | 2416 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) |
a9a08845 | 2417 | mask |= EPOLLHUP; |
1da177e4 | 2418 | if (tty_hung_up_p(file)) |
a9a08845 | 2419 | mask |= EPOLLHUP; |
f34d7a5b AC |
2420 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2421 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2422 | tty_write_room(tty) > 0) | |
a9a08845 | 2423 | mask |= EPOLLOUT | EPOLLWRNORM; |
1da177e4 LT |
2424 | return mask; |
2425 | } | |
2426 | ||
57c94121 | 2427 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2428 | { |
bc5a5e3f | 2429 | size_t nr, head, tail; |
47afa7a5 | 2430 | |
a73d3d69 | 2431 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2432 | return 0; |
ba2e68ac JS |
2433 | head = ldata->canon_head; |
2434 | tail = ldata->read_tail; | |
bc5a5e3f | 2435 | nr = head - tail; |
47afa7a5 | 2436 | /* Skip EOF-chars.. */ |
3d63b7e4 | 2437 | while (MASK(head) != MASK(tail)) { |
bc5a5e3f PH |
2438 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2439 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2440 | nr--; |
bc5a5e3f | 2441 | tail++; |
47afa7a5 AC |
2442 | } |
2443 | return nr; | |
2444 | } | |
2445 | ||
2446 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2447 | unsigned int cmd, unsigned long arg) | |
2448 | { | |
ba2e68ac | 2449 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2450 | int retval; |
2451 | ||
2452 | switch (cmd) { | |
2453 | case TIOCOUTQ: | |
2454 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2455 | case TIOCINQ: | |
6d76bd26 | 2456 | down_write(&tty->termios_rwsem); |
966031f3 | 2457 | if (L_ICANON(tty) && !L_EXTPROC(tty)) |
57c94121 | 2458 | retval = inq_canon(ldata); |
6d76bd26 PH |
2459 | else |
2460 | retval = read_cnt(ldata); | |
2461 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2462 | return put_user(retval, (unsigned int __user *) arg); |
2463 | default: | |
2464 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2465 | } | |
2466 | } | |
2467 | ||
27228732 | 2468 | static struct tty_ldisc_ops n_tty_ops = { |
e10cc1df PF |
2469 | .magic = TTY_LDISC_MAGIC, |
2470 | .name = "n_tty", | |
2471 | .open = n_tty_open, | |
2472 | .close = n_tty_close, | |
2473 | .flush_buffer = n_tty_flush_buffer, | |
11a96d18 AC |
2474 | .read = n_tty_read, |
2475 | .write = n_tty_write, | |
e10cc1df PF |
2476 | .ioctl = n_tty_ioctl, |
2477 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2478 | .poll = n_tty_poll, |
e10cc1df | 2479 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 | 2480 | .write_wakeup = n_tty_write_wakeup, |
24a89d1c | 2481 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2482 | }; |
572b9adb RG |
2483 | |
2484 | /** | |
2485 | * n_tty_inherit_ops - inherit N_TTY methods | |
2486 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2487 | * | |
27228732 | 2488 | * Enables a 'subclass' line discipline to 'inherit' N_TTY methods. |
572b9adb RG |
2489 | */ |
2490 | ||
2491 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2492 | { | |
27228732 | 2493 | *ops = n_tty_ops; |
572b9adb RG |
2494 | ops->owner = NULL; |
2495 | ops->refcount = ops->flags = 0; | |
2496 | } | |
2497 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); | |
27228732 PH |
2498 | |
2499 | void __init n_tty_init(void) | |
2500 | { | |
2501 | tty_register_ldisc(N_TTY, &n_tty_ops); | |
2502 | } |