Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * n_tty.c --- implements the N_TTY line discipline. | |
4edf1827 | 3 | * |
1da177e4 LT |
4 | * This code used to be in tty_io.c, but things are getting hairy |
5 | * enough that it made sense to split things off. (The N_TTY | |
6 | * processing has changed so much that it's hardly recognizable, | |
7 | * anyway...) | |
8 | * | |
9 | * Note that the open routine for N_TTY is guaranteed never to return | |
10 | * an error. This is because Linux will fall back to setting a line | |
4edf1827 | 11 | * to N_TTY if it can not switch to any other line discipline. |
1da177e4 LT |
12 | * |
13 | * Written by Theodore Ts'o, Copyright 1994. | |
4edf1827 | 14 | * |
1da177e4 LT |
15 | * This file also contains code originally written by Linus Torvalds, |
16 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. | |
4edf1827 | 17 | * |
1da177e4 LT |
18 | * This file may be redistributed under the terms of the GNU General Public |
19 | * License. | |
20 | * | |
21 | * Reduced memory usage for older ARM systems - Russell King. | |
22 | * | |
4edf1827 | 23 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
1da177e4 LT |
24 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
25 | * who actually finally proved there really was a race. | |
26 | * | |
27 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to | |
28 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. | |
11a96d18 | 29 | * Also fixed a bug in BLOCKING mode where n_tty_write returns |
1da177e4 LT |
30 | * EAGAIN |
31 | */ | |
32 | ||
33 | #include <linux/types.h> | |
34 | #include <linux/major.h> | |
35 | #include <linux/errno.h> | |
36 | #include <linux/signal.h> | |
37 | #include <linux/fcntl.h> | |
38 | #include <linux/sched.h> | |
39 | #include <linux/interrupt.h> | |
40 | #include <linux/tty.h> | |
41 | #include <linux/timer.h> | |
42 | #include <linux/ctype.h> | |
43 | #include <linux/mm.h> | |
44 | #include <linux/string.h> | |
45 | #include <linux/slab.h> | |
46 | #include <linux/poll.h> | |
47 | #include <linux/bitops.h> | |
522ed776 MT |
48 | #include <linux/audit.h> |
49 | #include <linux/file.h> | |
300a6204 | 50 | #include <linux/uaccess.h> |
572b9adb | 51 | #include <linux/module.h> |
1da177e4 | 52 | |
1da177e4 LT |
53 | #include <asm/system.h> |
54 | ||
55 | /* number of characters left in xmit buffer before select has we have room */ | |
56 | #define WAKEUP_CHARS 256 | |
57 | ||
58 | /* | |
59 | * This defines the low- and high-watermarks for throttling and | |
60 | * unthrottling the TTY driver. These watermarks are used for | |
61 | * controlling the space in the read buffer. | |
62 | */ | |
63 | #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ | |
64 | #define TTY_THRESHOLD_UNTHROTTLE 128 | |
65 | ||
a88a69c9 JP |
66 | /* |
67 | * Special byte codes used in the echo buffer to represent operations | |
68 | * or special handling of characters. Bytes in the echo buffer that | |
69 | * are not part of such special blocks are treated as normal character | |
70 | * codes. | |
71 | */ | |
72 | #define ECHO_OP_START 0xff | |
73 | #define ECHO_OP_MOVE_BACK_COL 0x80 | |
74 | #define ECHO_OP_SET_CANON_COL 0x81 | |
75 | #define ECHO_OP_ERASE_TAB 0x82 | |
76 | ||
522ed776 MT |
77 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
78 | unsigned char __user *ptr) | |
79 | { | |
80 | tty_audit_add_data(tty, &x, 1); | |
81 | return put_user(x, ptr); | |
82 | } | |
83 | ||
33f0f88f AC |
84 | /** |
85 | * n_tty_set__room - receive space | |
86 | * @tty: terminal | |
87 | * | |
88 | * Called by the driver to find out how much data it is | |
89 | * permitted to feed to the line discipline without any being lost | |
90 | * and thus to manage flow control. Not serialized. Answers for the | |
91 | * "instant". | |
92 | */ | |
93 | ||
94 | static void n_tty_set_room(struct tty_struct *tty) | |
95 | { | |
17b82060 | 96 | /* tty->read_cnt is not read locked ? */ |
33f0f88f AC |
97 | int left = N_TTY_BUF_SIZE - tty->read_cnt - 1; |
98 | ||
99 | /* | |
100 | * If we are doing input canonicalization, and there are no | |
101 | * pending newlines, let characters through without limit, so | |
102 | * that erase characters will be handled. Other excess | |
103 | * characters will be beeped. | |
104 | */ | |
105 | if (left <= 0) | |
106 | left = tty->icanon && !tty->canon_data; | |
107 | tty->receive_room = left; | |
108 | } | |
109 | ||
110 | static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty) | |
1da177e4 LT |
111 | { |
112 | if (tty->read_cnt < N_TTY_BUF_SIZE) { | |
113 | tty->read_buf[tty->read_head] = c; | |
114 | tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1); | |
115 | tty->read_cnt++; | |
116 | } | |
117 | } | |
118 | ||
17b82060 AC |
119 | /** |
120 | * put_tty_queue - add character to tty | |
121 | * @c: character | |
122 | * @tty: tty device | |
123 | * | |
124 | * Add a character to the tty read_buf queue. This is done under the | |
125 | * read_lock to serialize character addition and also to protect us | |
126 | * against parallel reads or flushes | |
127 | */ | |
128 | ||
33f0f88f | 129 | static void put_tty_queue(unsigned char c, struct tty_struct *tty) |
1da177e4 LT |
130 | { |
131 | unsigned long flags; | |
132 | /* | |
133 | * The problem of stomping on the buffers ends here. | |
134 | * Why didn't anyone see this one coming? --AJK | |
135 | */ | |
136 | spin_lock_irqsave(&tty->read_lock, flags); | |
137 | put_tty_queue_nolock(c, tty); | |
138 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
139 | } | |
140 | ||
141 | /** | |
142 | * check_unthrottle - allow new receive data | |
143 | * @tty; tty device | |
144 | * | |
17b82060 AC |
145 | * Check whether to call the driver unthrottle functions |
146 | * | |
70522e12 | 147 | * Can sleep, may be called under the atomic_read_lock mutex but |
1da177e4 LT |
148 | * this is not guaranteed. |
149 | */ | |
4edf1827 | 150 | static void check_unthrottle(struct tty_struct *tty) |
1da177e4 | 151 | { |
39c2e60f AC |
152 | if (tty->count) |
153 | tty_unthrottle(tty); | |
1da177e4 LT |
154 | } |
155 | ||
156 | /** | |
157 | * reset_buffer_flags - reset buffer state | |
158 | * @tty: terminal to reset | |
159 | * | |
4edf1827 | 160 | * Reset the read buffer counters, clear the flags, |
1da177e4 LT |
161 | * and make sure the driver is unthrottled. Called |
162 | * from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 AC |
163 | * |
164 | * Locking: tty_read_lock for read fields. | |
1da177e4 | 165 | */ |
a88a69c9 | 166 | |
1da177e4 LT |
167 | static void reset_buffer_flags(struct tty_struct *tty) |
168 | { | |
169 | unsigned long flags; | |
170 | ||
171 | spin_lock_irqsave(&tty->read_lock, flags); | |
172 | tty->read_head = tty->read_tail = tty->read_cnt = 0; | |
173 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
a88a69c9 JP |
174 | |
175 | mutex_lock(&tty->echo_lock); | |
176 | tty->echo_pos = tty->echo_cnt = tty->echo_overrun = 0; | |
177 | mutex_unlock(&tty->echo_lock); | |
178 | ||
1da177e4 LT |
179 | tty->canon_head = tty->canon_data = tty->erasing = 0; |
180 | memset(&tty->read_flags, 0, sizeof tty->read_flags); | |
33f0f88f | 181 | n_tty_set_room(tty); |
1da177e4 LT |
182 | check_unthrottle(tty); |
183 | } | |
184 | ||
185 | /** | |
186 | * n_tty_flush_buffer - clean input queue | |
187 | * @tty: terminal device | |
188 | * | |
189 | * Flush the input buffer. Called when the line discipline is | |
190 | * being closed, when the tty layer wants the buffer flushed (eg | |
191 | * at hangup) or when the N_TTY line discipline internally has to | |
192 | * clean the pending queue (for example some signals). | |
193 | * | |
17b82060 | 194 | * Locking: ctrl_lock, read_lock. |
1da177e4 | 195 | */ |
4edf1827 AC |
196 | |
197 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 198 | { |
04f378b1 | 199 | unsigned long flags; |
1da177e4 LT |
200 | /* clear everything and unthrottle the driver */ |
201 | reset_buffer_flags(tty); | |
4edf1827 | 202 | |
1da177e4 LT |
203 | if (!tty->link) |
204 | return; | |
205 | ||
04f378b1 | 206 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
1da177e4 LT |
207 | if (tty->link->packet) { |
208 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
209 | wake_up_interruptible(&tty->link->read_wait); | |
210 | } | |
04f378b1 | 211 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1da177e4 LT |
212 | } |
213 | ||
214 | /** | |
215 | * n_tty_chars_in_buffer - report available bytes | |
216 | * @tty: tty device | |
217 | * | |
218 | * Report the number of characters buffered to be delivered to user | |
4edf1827 | 219 | * at this instant in time. |
17b82060 AC |
220 | * |
221 | * Locking: read_lock | |
1da177e4 | 222 | */ |
4edf1827 | 223 | |
1da177e4 LT |
224 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
225 | { | |
226 | unsigned long flags; | |
227 | ssize_t n = 0; | |
228 | ||
229 | spin_lock_irqsave(&tty->read_lock, flags); | |
230 | if (!tty->icanon) { | |
231 | n = tty->read_cnt; | |
232 | } else if (tty->canon_data) { | |
233 | n = (tty->canon_head > tty->read_tail) ? | |
234 | tty->canon_head - tty->read_tail : | |
235 | tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail); | |
236 | } | |
237 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
238 | return n; | |
239 | } | |
240 | ||
241 | /** | |
242 | * is_utf8_continuation - utf8 multibyte check | |
243 | * @c: byte to check | |
244 | * | |
245 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
246 | * character. We use this to correctly compute the on screen size | |
247 | * of the character when printing | |
248 | */ | |
4edf1827 | 249 | |
1da177e4 LT |
250 | static inline int is_utf8_continuation(unsigned char c) |
251 | { | |
252 | return (c & 0xc0) == 0x80; | |
253 | } | |
254 | ||
255 | /** | |
256 | * is_continuation - multibyte check | |
257 | * @c: byte to check | |
258 | * | |
259 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
260 | * character and the terminal is in unicode mode. | |
261 | */ | |
4edf1827 | 262 | |
1da177e4 LT |
263 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
264 | { | |
265 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
266 | } | |
267 | ||
268 | /** | |
a88a69c9 | 269 | * do_output_char - output one character |
1da177e4 LT |
270 | * @c: character (or partial unicode symbol) |
271 | * @tty: terminal device | |
a88a69c9 | 272 | * @space: space available in tty driver write buffer |
1da177e4 | 273 | * |
a88a69c9 JP |
274 | * This is a helper function that handles one output character |
275 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
276 | * doing OPOST processing and putting the results in the |
277 | * tty driver's write buffer. | |
a88a69c9 JP |
278 | * |
279 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
280 | * and NLDLY. They simply aren't relevant in the world today. | |
281 | * If you ever need them, add them here. | |
1da177e4 | 282 | * |
a88a69c9 JP |
283 | * Returns the number of bytes of buffer space used or -1 if |
284 | * no space left. | |
285 | * | |
286 | * Locking: should be called under the output_lock to protect | |
287 | * the column state and space left in the buffer | |
1da177e4 | 288 | */ |
4edf1827 | 289 | |
a88a69c9 | 290 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 291 | { |
a88a69c9 | 292 | int spaces; |
1da177e4 | 293 | |
1da177e4 LT |
294 | if (!space) |
295 | return -1; | |
300a6204 | 296 | |
a88a69c9 JP |
297 | switch (c) { |
298 | case '\n': | |
299 | if (O_ONLRET(tty)) | |
300 | tty->column = 0; | |
301 | if (O_ONLCR(tty)) { | |
302 | if (space < 2) | |
303 | return -1; | |
1da177e4 | 304 | tty->canon_column = tty->column = 0; |
37f81fa1 | 305 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
306 | return 2; |
307 | } | |
308 | tty->canon_column = tty->column; | |
309 | break; | |
310 | case '\r': | |
311 | if (O_ONOCR(tty) && tty->column == 0) | |
312 | return 0; | |
313 | if (O_OCRNL(tty)) { | |
314 | c = '\n'; | |
315 | if (O_ONLRET(tty)) | |
316 | tty->canon_column = tty->column = 0; | |
1da177e4 | 317 | break; |
a88a69c9 JP |
318 | } |
319 | tty->canon_column = tty->column = 0; | |
320 | break; | |
321 | case '\t': | |
322 | spaces = 8 - (tty->column & 7); | |
323 | if (O_TABDLY(tty) == XTABS) { | |
324 | if (space < spaces) | |
325 | return -1; | |
1da177e4 | 326 | tty->column += spaces; |
a88a69c9 JP |
327 | tty->ops->write(tty, " ", spaces); |
328 | return spaces; | |
1da177e4 | 329 | } |
a88a69c9 JP |
330 | tty->column += spaces; |
331 | break; | |
332 | case '\b': | |
333 | if (tty->column > 0) | |
334 | tty->column--; | |
335 | break; | |
336 | default: | |
a59c0d6f JP |
337 | if (!iscntrl(c)) { |
338 | if (O_OLCUC(tty)) | |
339 | c = toupper(c); | |
340 | if (!is_continuation(c, tty)) | |
341 | tty->column++; | |
342 | } | |
a88a69c9 | 343 | break; |
1da177e4 | 344 | } |
a88a69c9 | 345 | |
f34d7a5b | 346 | tty_put_char(tty, c); |
a88a69c9 JP |
347 | return 1; |
348 | } | |
349 | ||
350 | /** | |
351 | * process_output - output post processor | |
352 | * @c: character (or partial unicode symbol) | |
353 | * @tty: terminal device | |
354 | * | |
ee5aa7b8 JP |
355 | * Output one character with OPOST processing. |
356 | * Returns -1 when the output device is full and the character | |
357 | * must be retried. | |
a88a69c9 JP |
358 | * |
359 | * Locking: output_lock to protect column state and space left | |
360 | * (also, this is called from n_tty_write under the | |
361 | * tty layer write lock) | |
362 | */ | |
363 | ||
364 | static int process_output(unsigned char c, struct tty_struct *tty) | |
365 | { | |
366 | int space, retval; | |
367 | ||
368 | mutex_lock(&tty->output_lock); | |
369 | ||
370 | space = tty_write_room(tty); | |
371 | retval = do_output_char(c, tty, space); | |
372 | ||
373 | mutex_unlock(&tty->output_lock); | |
374 | if (retval < 0) | |
375 | return -1; | |
376 | else | |
377 | return 0; | |
1da177e4 LT |
378 | } |
379 | ||
380 | /** | |
a88a69c9 | 381 | * process_output_block - block post processor |
1da177e4 | 382 | * @tty: terminal device |
ee5aa7b8 JP |
383 | * @buf: character buffer |
384 | * @nr: number of bytes to output | |
385 | * | |
386 | * Output a block of characters with OPOST processing. | |
387 | * Returns the number of characters output. | |
1da177e4 LT |
388 | * |
389 | * This path is used to speed up block console writes, among other | |
390 | * things when processing blocks of output data. It handles only | |
391 | * the simple cases normally found and helps to generate blocks of | |
392 | * symbols for the console driver and thus improve performance. | |
393 | * | |
a88a69c9 JP |
394 | * Locking: output_lock to protect column state and space left |
395 | * (also, this is called from n_tty_write under the | |
396 | * tty layer write lock) | |
1da177e4 | 397 | */ |
4edf1827 | 398 | |
a88a69c9 JP |
399 | static ssize_t process_output_block(struct tty_struct *tty, |
400 | const unsigned char *buf, unsigned int nr) | |
1da177e4 LT |
401 | { |
402 | int space; | |
403 | int i; | |
404 | const unsigned char *cp; | |
405 | ||
a88a69c9 JP |
406 | mutex_lock(&tty->output_lock); |
407 | ||
f34d7a5b | 408 | space = tty_write_room(tty); |
300a6204 | 409 | if (!space) { |
a88a69c9 | 410 | mutex_unlock(&tty->output_lock); |
1da177e4 | 411 | return 0; |
a88a69c9 | 412 | } |
1da177e4 LT |
413 | if (nr > space) |
414 | nr = space; | |
415 | ||
416 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
417 | unsigned char c = *cp; |
418 | ||
419 | switch (c) { | |
1da177e4 LT |
420 | case '\n': |
421 | if (O_ONLRET(tty)) | |
422 | tty->column = 0; | |
423 | if (O_ONLCR(tty)) | |
424 | goto break_out; | |
425 | tty->canon_column = tty->column; | |
426 | break; | |
427 | case '\r': | |
428 | if (O_ONOCR(tty) && tty->column == 0) | |
429 | goto break_out; | |
430 | if (O_OCRNL(tty)) | |
431 | goto break_out; | |
432 | tty->canon_column = tty->column = 0; | |
433 | break; | |
434 | case '\t': | |
435 | goto break_out; | |
436 | case '\b': | |
437 | if (tty->column > 0) | |
438 | tty->column--; | |
439 | break; | |
440 | default: | |
a59c0d6f JP |
441 | if (!iscntrl(c)) { |
442 | if (O_OLCUC(tty)) | |
443 | goto break_out; | |
444 | if (!is_continuation(c, tty)) | |
445 | tty->column++; | |
446 | } | |
1da177e4 LT |
447 | break; |
448 | } | |
449 | } | |
450 | break_out: | |
f34d7a5b | 451 | i = tty->ops->write(tty, buf, i); |
a88a69c9 JP |
452 | |
453 | mutex_unlock(&tty->output_lock); | |
1da177e4 LT |
454 | return i; |
455 | } | |
456 | ||
a88a69c9 JP |
457 | /** |
458 | * process_echoes - write pending echo characters | |
459 | * @tty: terminal device | |
460 | * | |
461 | * Write previously buffered echo (and other ldisc-generated) | |
462 | * characters to the tty. | |
463 | * | |
464 | * Characters generated by the ldisc (including echoes) need to | |
465 | * be buffered because the driver's write buffer can fill during | |
466 | * heavy program output. Echoing straight to the driver will | |
467 | * often fail under these conditions, causing lost characters and | |
468 | * resulting mismatches of ldisc state information. | |
469 | * | |
470 | * Since the ldisc state must represent the characters actually sent | |
471 | * to the driver at the time of the write, operations like certain | |
472 | * changes in column state are also saved in the buffer and executed | |
473 | * here. | |
474 | * | |
475 | * A circular fifo buffer is used so that the most recent characters | |
476 | * are prioritized. Also, when control characters are echoed with a | |
477 | * prefixed "^", the pair is treated atomically and thus not separated. | |
478 | * | |
479 | * Locking: output_lock to protect column state and space left, | |
480 | * echo_lock to protect the echo buffer | |
481 | */ | |
482 | ||
483 | static void process_echoes(struct tty_struct *tty) | |
484 | { | |
485 | int space, nr; | |
486 | unsigned char c; | |
487 | unsigned char *cp, *buf_end; | |
488 | ||
489 | if (!tty->echo_cnt) | |
490 | return; | |
491 | ||
492 | mutex_lock(&tty->output_lock); | |
493 | mutex_lock(&tty->echo_lock); | |
494 | ||
495 | space = tty_write_room(tty); | |
496 | ||
497 | buf_end = tty->echo_buf + N_TTY_BUF_SIZE; | |
498 | cp = tty->echo_buf + tty->echo_pos; | |
499 | nr = tty->echo_cnt; | |
500 | while (nr > 0) { | |
501 | c = *cp; | |
502 | if (c == ECHO_OP_START) { | |
503 | unsigned char op; | |
504 | unsigned char *opp; | |
505 | int no_space_left = 0; | |
506 | ||
507 | /* | |
508 | * If the buffer byte is the start of a multi-byte | |
509 | * operation, get the next byte, which is either the | |
510 | * op code or a control character value. | |
511 | */ | |
512 | opp = cp + 1; | |
513 | if (opp == buf_end) | |
514 | opp -= N_TTY_BUF_SIZE; | |
515 | op = *opp; | |
300a6204 | 516 | |
a88a69c9 JP |
517 | switch (op) { |
518 | unsigned int num_chars, num_bs; | |
519 | ||
520 | case ECHO_OP_ERASE_TAB: | |
521 | if (++opp == buf_end) | |
522 | opp -= N_TTY_BUF_SIZE; | |
523 | num_chars = *opp; | |
524 | ||
525 | /* | |
526 | * Determine how many columns to go back | |
527 | * in order to erase the tab. | |
528 | * This depends on the number of columns | |
529 | * used by other characters within the tab | |
530 | * area. If this (modulo 8) count is from | |
531 | * the start of input rather than from a | |
532 | * previous tab, we offset by canon column. | |
533 | * Otherwise, tab spacing is normal. | |
534 | */ | |
535 | if (!(num_chars & 0x80)) | |
536 | num_chars += tty->canon_column; | |
537 | num_bs = 8 - (num_chars & 7); | |
538 | ||
539 | if (num_bs > space) { | |
540 | no_space_left = 1; | |
541 | break; | |
542 | } | |
543 | space -= num_bs; | |
544 | while (num_bs--) { | |
545 | tty_put_char(tty, '\b'); | |
546 | if (tty->column > 0) | |
547 | tty->column--; | |
548 | } | |
549 | cp += 3; | |
550 | nr -= 3; | |
551 | break; | |
552 | ||
553 | case ECHO_OP_SET_CANON_COL: | |
554 | tty->canon_column = tty->column; | |
555 | cp += 2; | |
556 | nr -= 2; | |
557 | break; | |
558 | ||
559 | case ECHO_OP_MOVE_BACK_COL: | |
560 | if (tty->column > 0) | |
561 | tty->column--; | |
562 | cp += 2; | |
563 | nr -= 2; | |
564 | break; | |
565 | ||
566 | case ECHO_OP_START: | |
567 | /* This is an escaped echo op start code */ | |
568 | if (!space) { | |
569 | no_space_left = 1; | |
570 | break; | |
571 | } | |
572 | tty_put_char(tty, ECHO_OP_START); | |
573 | tty->column++; | |
574 | space--; | |
575 | cp += 2; | |
576 | nr -= 2; | |
577 | break; | |
578 | ||
579 | default: | |
a88a69c9 | 580 | /* |
62b26358 JP |
581 | * If the op is not a special byte code, |
582 | * it is a ctrl char tagged to be echoed | |
583 | * as "^X" (where X is the letter | |
584 | * representing the control char). | |
585 | * Note that we must ensure there is | |
586 | * enough space for the whole ctrl pair. | |
587 | * | |
a88a69c9 | 588 | */ |
62b26358 JP |
589 | if (space < 2) { |
590 | no_space_left = 1; | |
591 | break; | |
592 | } | |
593 | tty_put_char(tty, '^'); | |
594 | tty_put_char(tty, op ^ 0100); | |
595 | tty->column += 2; | |
596 | space -= 2; | |
a88a69c9 JP |
597 | cp += 2; |
598 | nr -= 2; | |
599 | } | |
600 | ||
601 | if (no_space_left) | |
602 | break; | |
603 | } else { | |
ee5aa7b8 JP |
604 | if (O_OPOST(tty) && |
605 | !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
606 | int retval = do_output_char(c, tty, space); | |
607 | if (retval < 0) | |
608 | break; | |
609 | space -= retval; | |
610 | } else { | |
611 | if (!space) | |
612 | break; | |
613 | tty_put_char(tty, c); | |
614 | space -= 1; | |
615 | } | |
a88a69c9 JP |
616 | cp += 1; |
617 | nr -= 1; | |
618 | } | |
619 | ||
620 | /* When end of circular buffer reached, wrap around */ | |
621 | if (cp >= buf_end) | |
622 | cp -= N_TTY_BUF_SIZE; | |
623 | } | |
624 | ||
625 | if (nr == 0) { | |
626 | tty->echo_pos = 0; | |
627 | tty->echo_cnt = 0; | |
628 | tty->echo_overrun = 0; | |
629 | } else { | |
630 | int num_processed = tty->echo_cnt - nr; | |
631 | tty->echo_pos += num_processed; | |
632 | tty->echo_pos &= N_TTY_BUF_SIZE - 1; | |
633 | tty->echo_cnt = nr; | |
634 | if (num_processed > 0) | |
635 | tty->echo_overrun = 0; | |
636 | } | |
637 | ||
638 | mutex_unlock(&tty->echo_lock); | |
639 | mutex_unlock(&tty->output_lock); | |
640 | ||
641 | if (tty->ops->flush_chars) | |
642 | tty->ops->flush_chars(tty); | |
643 | } | |
644 | ||
645 | /** | |
646 | * add_echo_byte - add a byte to the echo buffer | |
647 | * @c: unicode byte to echo | |
648 | * @tty: terminal device | |
649 | * | |
650 | * Add a character or operation byte to the echo buffer. | |
651 | * | |
652 | * Should be called under the echo lock to protect the echo buffer. | |
653 | */ | |
654 | ||
655 | static void add_echo_byte(unsigned char c, struct tty_struct *tty) | |
656 | { | |
657 | int new_byte_pos; | |
658 | ||
659 | if (tty->echo_cnt == N_TTY_BUF_SIZE) { | |
660 | /* Circular buffer is already at capacity */ | |
661 | new_byte_pos = tty->echo_pos; | |
662 | ||
663 | /* | |
664 | * Since the buffer start position needs to be advanced, | |
665 | * be sure to step by a whole operation byte group. | |
666 | */ | |
300a6204 | 667 | if (tty->echo_buf[tty->echo_pos] == ECHO_OP_START) { |
a88a69c9 JP |
668 | if (tty->echo_buf[(tty->echo_pos + 1) & |
669 | (N_TTY_BUF_SIZE - 1)] == | |
670 | ECHO_OP_ERASE_TAB) { | |
671 | tty->echo_pos += 3; | |
672 | tty->echo_cnt -= 2; | |
673 | } else { | |
674 | tty->echo_pos += 2; | |
675 | tty->echo_cnt -= 1; | |
676 | } | |
677 | } else { | |
678 | tty->echo_pos++; | |
679 | } | |
680 | tty->echo_pos &= N_TTY_BUF_SIZE - 1; | |
681 | ||
682 | tty->echo_overrun = 1; | |
683 | } else { | |
684 | new_byte_pos = tty->echo_pos + tty->echo_cnt; | |
685 | new_byte_pos &= N_TTY_BUF_SIZE - 1; | |
686 | tty->echo_cnt++; | |
687 | } | |
688 | ||
689 | tty->echo_buf[new_byte_pos] = c; | |
690 | } | |
691 | ||
692 | /** | |
693 | * echo_move_back_col - add operation to move back a column | |
694 | * @tty: terminal device | |
695 | * | |
696 | * Add an operation to the echo buffer to move back one column. | |
697 | * | |
698 | * Locking: echo_lock to protect the echo buffer | |
699 | */ | |
700 | ||
701 | static void echo_move_back_col(struct tty_struct *tty) | |
702 | { | |
703 | mutex_lock(&tty->echo_lock); | |
704 | ||
705 | add_echo_byte(ECHO_OP_START, tty); | |
706 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty); | |
707 | ||
708 | mutex_unlock(&tty->echo_lock); | |
709 | } | |
710 | ||
711 | /** | |
712 | * echo_set_canon_col - add operation to set the canon column | |
713 | * @tty: terminal device | |
714 | * | |
715 | * Add an operation to the echo buffer to set the canon column | |
716 | * to the current column. | |
717 | * | |
718 | * Locking: echo_lock to protect the echo buffer | |
719 | */ | |
720 | ||
721 | static void echo_set_canon_col(struct tty_struct *tty) | |
722 | { | |
723 | mutex_lock(&tty->echo_lock); | |
724 | ||
725 | add_echo_byte(ECHO_OP_START, tty); | |
726 | add_echo_byte(ECHO_OP_SET_CANON_COL, tty); | |
727 | ||
728 | mutex_unlock(&tty->echo_lock); | |
729 | } | |
730 | ||
731 | /** | |
732 | * echo_erase_tab - add operation to erase a tab | |
733 | * @num_chars: number of character columns already used | |
734 | * @after_tab: true if num_chars starts after a previous tab | |
735 | * @tty: terminal device | |
736 | * | |
737 | * Add an operation to the echo buffer to erase a tab. | |
738 | * | |
739 | * Called by the eraser function, which knows how many character | |
740 | * columns have been used since either a previous tab or the start | |
741 | * of input. This information will be used later, along with | |
742 | * canon column (if applicable), to go back the correct number | |
743 | * of columns. | |
744 | * | |
745 | * Locking: echo_lock to protect the echo buffer | |
746 | */ | |
747 | ||
748 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
749 | struct tty_struct *tty) | |
750 | { | |
751 | mutex_lock(&tty->echo_lock); | |
752 | ||
753 | add_echo_byte(ECHO_OP_START, tty); | |
754 | add_echo_byte(ECHO_OP_ERASE_TAB, tty); | |
755 | ||
756 | /* We only need to know this modulo 8 (tab spacing) */ | |
757 | num_chars &= 7; | |
758 | ||
759 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
760 | if (after_tab) | |
761 | num_chars |= 0x80; | |
300a6204 | 762 | |
a88a69c9 JP |
763 | add_echo_byte(num_chars, tty); |
764 | ||
765 | mutex_unlock(&tty->echo_lock); | |
766 | } | |
767 | ||
768 | /** | |
769 | * echo_char_raw - echo a character raw | |
770 | * @c: unicode byte to echo | |
771 | * @tty: terminal device | |
772 | * | |
773 | * Echo user input back onto the screen. This must be called only when | |
774 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
775 | * | |
776 | * This variant does not treat control characters specially. | |
777 | * | |
778 | * Locking: echo_lock to protect the echo buffer | |
779 | */ | |
780 | ||
781 | static void echo_char_raw(unsigned char c, struct tty_struct *tty) | |
782 | { | |
783 | mutex_lock(&tty->echo_lock); | |
784 | ||
785 | if (c == ECHO_OP_START) { | |
786 | add_echo_byte(ECHO_OP_START, tty); | |
787 | add_echo_byte(ECHO_OP_START, tty); | |
788 | } else { | |
789 | add_echo_byte(c, tty); | |
790 | } | |
791 | ||
792 | mutex_unlock(&tty->echo_lock); | |
793 | } | |
1da177e4 | 794 | |
1da177e4 | 795 | /** |
a88a69c9 | 796 | * echo_char - echo a character |
1da177e4 LT |
797 | * @c: unicode byte to echo |
798 | * @tty: terminal device | |
799 | * | |
4edf1827 | 800 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 801 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 802 | * |
62b26358 JP |
803 | * This variant tags control characters to be echoed as "^X" |
804 | * (where X is the letter representing the control char). | |
a88a69c9 JP |
805 | * |
806 | * Locking: echo_lock to protect the echo buffer | |
1da177e4 LT |
807 | */ |
808 | ||
809 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
810 | { | |
a88a69c9 JP |
811 | mutex_lock(&tty->echo_lock); |
812 | ||
813 | if (c == ECHO_OP_START) { | |
814 | add_echo_byte(ECHO_OP_START, tty); | |
815 | add_echo_byte(ECHO_OP_START, tty); | |
816 | } else { | |
62b26358 | 817 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
a88a69c9 JP |
818 | add_echo_byte(ECHO_OP_START, tty); |
819 | add_echo_byte(c, tty); | |
820 | } | |
821 | ||
822 | mutex_unlock(&tty->echo_lock); | |
1da177e4 LT |
823 | } |
824 | ||
17b82060 | 825 | /** |
a88a69c9 | 826 | * finish_erasing - complete erase |
17b82060 | 827 | * @tty: tty doing the erase |
17b82060 | 828 | */ |
a88a69c9 | 829 | |
1da177e4 LT |
830 | static inline void finish_erasing(struct tty_struct *tty) |
831 | { | |
832 | if (tty->erasing) { | |
a88a69c9 | 833 | echo_char_raw('/', tty); |
1da177e4 LT |
834 | tty->erasing = 0; |
835 | } | |
836 | } | |
837 | ||
838 | /** | |
839 | * eraser - handle erase function | |
840 | * @c: character input | |
841 | * @tty: terminal device | |
842 | * | |
3a4fa0a2 | 843 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
844 | * present in the stream from the driver layer. Handles the complexities |
845 | * of UTF-8 multibyte symbols. | |
17b82060 | 846 | * |
a88a69c9 | 847 | * Locking: read_lock for tty buffers |
1da177e4 | 848 | */ |
4edf1827 | 849 | |
1da177e4 LT |
850 | static void eraser(unsigned char c, struct tty_struct *tty) |
851 | { | |
852 | enum { ERASE, WERASE, KILL } kill_type; | |
853 | int head, seen_alnums, cnt; | |
854 | unsigned long flags; | |
855 | ||
17b82060 | 856 | /* FIXME: locking needed ? */ |
1da177e4 | 857 | if (tty->read_head == tty->canon_head) { |
7e94b1d9 | 858 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
859 | return; |
860 | } | |
861 | if (c == ERASE_CHAR(tty)) | |
862 | kill_type = ERASE; | |
863 | else if (c == WERASE_CHAR(tty)) | |
864 | kill_type = WERASE; | |
865 | else { | |
866 | if (!L_ECHO(tty)) { | |
867 | spin_lock_irqsave(&tty->read_lock, flags); | |
868 | tty->read_cnt -= ((tty->read_head - tty->canon_head) & | |
869 | (N_TTY_BUF_SIZE - 1)); | |
870 | tty->read_head = tty->canon_head; | |
871 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
872 | return; | |
873 | } | |
874 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
875 | spin_lock_irqsave(&tty->read_lock, flags); | |
876 | tty->read_cnt -= ((tty->read_head - tty->canon_head) & | |
877 | (N_TTY_BUF_SIZE - 1)); | |
878 | tty->read_head = tty->canon_head; | |
879 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
880 | finish_erasing(tty); | |
881 | echo_char(KILL_CHAR(tty), tty); | |
882 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
883 | if (L_ECHOK(tty)) | |
a88a69c9 | 884 | echo_char_raw('\n', tty); |
1da177e4 LT |
885 | return; |
886 | } | |
887 | kill_type = KILL; | |
888 | } | |
889 | ||
890 | seen_alnums = 0; | |
17b82060 | 891 | /* FIXME: Locking ?? */ |
1da177e4 LT |
892 | while (tty->read_head != tty->canon_head) { |
893 | head = tty->read_head; | |
894 | ||
895 | /* erase a single possibly multibyte character */ | |
896 | do { | |
897 | head = (head - 1) & (N_TTY_BUF_SIZE-1); | |
898 | c = tty->read_buf[head]; | |
899 | } while (is_continuation(c, tty) && head != tty->canon_head); | |
900 | ||
901 | /* do not partially erase */ | |
902 | if (is_continuation(c, tty)) | |
903 | break; | |
904 | ||
905 | if (kill_type == WERASE) { | |
906 | /* Equivalent to BSD's ALTWERASE. */ | |
907 | if (isalnum(c) || c == '_') | |
908 | seen_alnums++; | |
909 | else if (seen_alnums) | |
910 | break; | |
911 | } | |
912 | cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1); | |
913 | spin_lock_irqsave(&tty->read_lock, flags); | |
914 | tty->read_head = head; | |
915 | tty->read_cnt -= cnt; | |
916 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
917 | if (L_ECHO(tty)) { | |
918 | if (L_ECHOPRT(tty)) { | |
919 | if (!tty->erasing) { | |
a88a69c9 | 920 | echo_char_raw('\\', tty); |
1da177e4 LT |
921 | tty->erasing = 1; |
922 | } | |
923 | /* if cnt > 1, output a multi-byte character */ | |
924 | echo_char(c, tty); | |
925 | while (--cnt > 0) { | |
926 | head = (head+1) & (N_TTY_BUF_SIZE-1); | |
a88a69c9 JP |
927 | echo_char_raw(tty->read_buf[head], tty); |
928 | echo_move_back_col(tty); | |
1da177e4 LT |
929 | } |
930 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
931 | echo_char(ERASE_CHAR(tty), tty); | |
932 | } else if (c == '\t') { | |
a88a69c9 JP |
933 | unsigned int num_chars = 0; |
934 | int after_tab = 0; | |
935 | unsigned long tail = tty->read_head; | |
936 | ||
937 | /* | |
938 | * Count the columns used for characters | |
939 | * since the start of input or after a | |
940 | * previous tab. | |
941 | * This info is used to go back the correct | |
942 | * number of columns. | |
943 | */ | |
944 | while (tail != tty->canon_head) { | |
945 | tail = (tail-1) & (N_TTY_BUF_SIZE-1); | |
1da177e4 | 946 | c = tty->read_buf[tail]; |
a88a69c9 JP |
947 | if (c == '\t') { |
948 | after_tab = 1; | |
949 | break; | |
300a6204 | 950 | } else if (iscntrl(c)) { |
1da177e4 | 951 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
952 | num_chars += 2; |
953 | } else if (!is_continuation(c, tty)) { | |
954 | num_chars++; | |
955 | } | |
1da177e4 | 956 | } |
a88a69c9 | 957 | echo_erase_tab(num_chars, after_tab, tty); |
1da177e4 LT |
958 | } else { |
959 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
a88a69c9 JP |
960 | echo_char_raw('\b', tty); |
961 | echo_char_raw(' ', tty); | |
962 | echo_char_raw('\b', tty); | |
1da177e4 LT |
963 | } |
964 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
a88a69c9 JP |
965 | echo_char_raw('\b', tty); |
966 | echo_char_raw(' ', tty); | |
967 | echo_char_raw('\b', tty); | |
1da177e4 LT |
968 | } |
969 | } | |
970 | } | |
971 | if (kill_type == ERASE) | |
972 | break; | |
973 | } | |
a88a69c9 | 974 | if (tty->read_head == tty->canon_head && L_ECHO(tty)) |
1da177e4 LT |
975 | finish_erasing(tty); |
976 | } | |
977 | ||
978 | /** | |
979 | * isig - handle the ISIG optio | |
980 | * @sig: signal | |
981 | * @tty: terminal | |
982 | * @flush: force flush | |
983 | * | |
984 | * Called when a signal is being sent due to terminal input. This | |
985 | * may caus terminal flushing to take place according to the termios | |
986 | * settings and character used. Called from the driver receive_buf | |
987 | * path so serialized. | |
17b82060 AC |
988 | * |
989 | * Locking: ctrl_lock, read_lock (both via flush buffer) | |
1da177e4 | 990 | */ |
4edf1827 | 991 | |
1da177e4 LT |
992 | static inline void isig(int sig, struct tty_struct *tty, int flush) |
993 | { | |
ab521dc0 EB |
994 | if (tty->pgrp) |
995 | kill_pgrp(tty->pgrp, sig, 1); | |
1da177e4 LT |
996 | if (flush || !L_NOFLSH(tty)) { |
997 | n_tty_flush_buffer(tty); | |
f34d7a5b | 998 | tty_driver_flush_buffer(tty); |
1da177e4 LT |
999 | } |
1000 | } | |
1001 | ||
1002 | /** | |
1003 | * n_tty_receive_break - handle break | |
1004 | * @tty: terminal | |
1005 | * | |
1006 | * An RS232 break event has been hit in the incoming bitstream. This | |
1007 | * can cause a variety of events depending upon the termios settings. | |
1008 | * | |
1009 | * Called from the receive_buf path so single threaded. | |
1010 | */ | |
4edf1827 | 1011 | |
1da177e4 LT |
1012 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1013 | { | |
1014 | if (I_IGNBRK(tty)) | |
1015 | return; | |
1016 | if (I_BRKINT(tty)) { | |
1017 | isig(SIGINT, tty, 1); | |
1018 | return; | |
1019 | } | |
1020 | if (I_PARMRK(tty)) { | |
1021 | put_tty_queue('\377', tty); | |
1022 | put_tty_queue('\0', tty); | |
1023 | } | |
1024 | put_tty_queue('\0', tty); | |
1025 | wake_up_interruptible(&tty->read_wait); | |
1026 | } | |
1027 | ||
1028 | /** | |
1029 | * n_tty_receive_overrun - handle overrun reporting | |
1030 | * @tty: terminal | |
1031 | * | |
1032 | * Data arrived faster than we could process it. While the tty | |
1033 | * driver has flagged this the bits that were missed are gone | |
1034 | * forever. | |
1035 | * | |
1036 | * Called from the receive_buf path so single threaded. Does not | |
1037 | * need locking as num_overrun and overrun_time are function | |
1038 | * private. | |
1039 | */ | |
4edf1827 | 1040 | |
1da177e4 LT |
1041 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1042 | { | |
1043 | char buf[64]; | |
1044 | ||
1045 | tty->num_overrun++; | |
1046 | if (time_before(tty->overrun_time, jiffies - HZ) || | |
1047 | time_after(tty->overrun_time, jiffies)) { | |
1048 | printk(KERN_WARNING "%s: %d input overrun(s)\n", | |
1049 | tty_name(tty, buf), | |
1050 | tty->num_overrun); | |
1051 | tty->overrun_time = jiffies; | |
1052 | tty->num_overrun = 0; | |
1053 | } | |
1054 | } | |
1055 | ||
1056 | /** | |
1057 | * n_tty_receive_parity_error - error notifier | |
1058 | * @tty: terminal device | |
1059 | * @c: character | |
1060 | * | |
1061 | * Process a parity error and queue the right data to indicate | |
3a4fa0a2 | 1062 | * the error case if necessary. Locking as per n_tty_receive_buf. |
1da177e4 LT |
1063 | */ |
1064 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1065 | unsigned char c) | |
1066 | { | |
4edf1827 | 1067 | if (I_IGNPAR(tty)) |
1da177e4 | 1068 | return; |
1da177e4 LT |
1069 | if (I_PARMRK(tty)) { |
1070 | put_tty_queue('\377', tty); | |
1071 | put_tty_queue('\0', tty); | |
1072 | put_tty_queue(c, tty); | |
1073 | } else if (I_INPCK(tty)) | |
1074 | put_tty_queue('\0', tty); | |
1075 | else | |
1076 | put_tty_queue(c, tty); | |
1077 | wake_up_interruptible(&tty->read_wait); | |
1078 | } | |
1079 | ||
1080 | /** | |
1081 | * n_tty_receive_char - perform processing | |
1082 | * @tty: terminal device | |
1083 | * @c: character | |
1084 | * | |
1085 | * Process an individual character of input received from the driver. | |
4edf1827 | 1086 | * This is serialized with respect to itself by the rules for the |
1da177e4 LT |
1087 | * driver above. |
1088 | */ | |
1089 | ||
1090 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1091 | { | |
1092 | unsigned long flags; | |
acc71bba | 1093 | int parmrk; |
1da177e4 LT |
1094 | |
1095 | if (tty->raw) { | |
1096 | put_tty_queue(c, tty); | |
1097 | return; | |
1098 | } | |
4edf1827 | 1099 | |
1da177e4 LT |
1100 | if (I_ISTRIP(tty)) |
1101 | c &= 0x7f; | |
1102 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1103 | c = tolower(c); |
1da177e4 | 1104 | |
26df6d13 | 1105 | if (L_EXTPROC(tty)) { |
1106 | put_tty_queue(c, tty); | |
1107 | return; | |
1108 | } | |
1109 | ||
54d2a37e | 1110 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1111 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1112 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1113 | start_tty(tty); |
a88a69c9 JP |
1114 | process_echoes(tty); |
1115 | } | |
54d2a37e | 1116 | |
1da177e4 LT |
1117 | if (tty->closing) { |
1118 | if (I_IXON(tty)) { | |
a88a69c9 | 1119 | if (c == START_CHAR(tty)) { |
1da177e4 | 1120 | start_tty(tty); |
a88a69c9 | 1121 | process_echoes(tty); |
300a6204 | 1122 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1123 | stop_tty(tty); |
1124 | } | |
1125 | return; | |
1126 | } | |
1127 | ||
1128 | /* | |
1129 | * If the previous character was LNEXT, or we know that this | |
1130 | * character is not one of the characters that we'll have to | |
1131 | * handle specially, do shortcut processing to speed things | |
1132 | * up. | |
1133 | */ | |
1134 | if (!test_bit(c, tty->process_char_map) || tty->lnext) { | |
1da177e4 | 1135 | tty->lnext = 0; |
acc71bba JP |
1136 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
1137 | if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { | |
1138 | /* beep if no space */ | |
7e94b1d9 JP |
1139 | if (L_ECHO(tty)) |
1140 | process_output('\a', tty); | |
acc71bba JP |
1141 | return; |
1142 | } | |
1143 | if (L_ECHO(tty)) { | |
1144 | finish_erasing(tty); | |
1da177e4 LT |
1145 | /* Record the column of first canon char. */ |
1146 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1147 | echo_set_canon_col(tty); |
1da177e4 | 1148 | echo_char(c, tty); |
a88a69c9 | 1149 | process_echoes(tty); |
1da177e4 | 1150 | } |
acc71bba | 1151 | if (parmrk) |
1da177e4 LT |
1152 | put_tty_queue(c, tty); |
1153 | put_tty_queue(c, tty); | |
1154 | return; | |
1155 | } | |
4edf1827 | 1156 | |
1da177e4 LT |
1157 | if (I_IXON(tty)) { |
1158 | if (c == START_CHAR(tty)) { | |
1159 | start_tty(tty); | |
a88a69c9 | 1160 | process_echoes(tty); |
1da177e4 LT |
1161 | return; |
1162 | } | |
1163 | if (c == STOP_CHAR(tty)) { | |
1164 | stop_tty(tty); | |
1165 | return; | |
1166 | } | |
1167 | } | |
575537b3 | 1168 | |
1da177e4 LT |
1169 | if (L_ISIG(tty)) { |
1170 | int signal; | |
1171 | signal = SIGINT; | |
1172 | if (c == INTR_CHAR(tty)) | |
1173 | goto send_signal; | |
1174 | signal = SIGQUIT; | |
1175 | if (c == QUIT_CHAR(tty)) | |
1176 | goto send_signal; | |
1177 | signal = SIGTSTP; | |
1178 | if (c == SUSP_CHAR(tty)) { | |
1179 | send_signal: | |
ec5b1157 | 1180 | /* |
ec5b1157 JP |
1181 | * Note that we do not use isig() here because we want |
1182 | * the order to be: | |
1183 | * 1) flush, 2) echo, 3) signal | |
1184 | */ | |
1185 | if (!L_NOFLSH(tty)) { | |
1186 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1187 | tty_driver_flush_buffer(tty); |
ec5b1157 | 1188 | } |
a88a69c9 JP |
1189 | if (I_IXON(tty)) |
1190 | start_tty(tty); | |
1191 | if (L_ECHO(tty)) { | |
ec5b1157 | 1192 | echo_char(c, tty); |
a88a69c9 JP |
1193 | process_echoes(tty); |
1194 | } | |
ec5b1157 JP |
1195 | if (tty->pgrp) |
1196 | kill_pgrp(tty->pgrp, signal, 1); | |
1da177e4 LT |
1197 | return; |
1198 | } | |
1199 | } | |
575537b3 JP |
1200 | |
1201 | if (c == '\r') { | |
1202 | if (I_IGNCR(tty)) | |
1203 | return; | |
1204 | if (I_ICRNL(tty)) | |
1205 | c = '\n'; | |
1206 | } else if (c == '\n' && I_INLCR(tty)) | |
1207 | c = '\r'; | |
1208 | ||
1da177e4 LT |
1209 | if (tty->icanon) { |
1210 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || | |
1211 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1212 | eraser(c, tty); | |
a88a69c9 | 1213 | process_echoes(tty); |
1da177e4 LT |
1214 | return; |
1215 | } | |
1216 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
1217 | tty->lnext = 1; | |
1218 | if (L_ECHO(tty)) { | |
1219 | finish_erasing(tty); | |
1220 | if (L_ECHOCTL(tty)) { | |
a88a69c9 JP |
1221 | echo_char_raw('^', tty); |
1222 | echo_char_raw('\b', tty); | |
1223 | process_echoes(tty); | |
1da177e4 LT |
1224 | } |
1225 | } | |
1226 | return; | |
1227 | } | |
1228 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1229 | L_IEXTEN(tty)) { | |
1230 | unsigned long tail = tty->canon_head; | |
1231 | ||
1232 | finish_erasing(tty); | |
1233 | echo_char(c, tty); | |
a88a69c9 | 1234 | echo_char_raw('\n', tty); |
1da177e4 LT |
1235 | while (tail != tty->read_head) { |
1236 | echo_char(tty->read_buf[tail], tty); | |
1237 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
1238 | } | |
a88a69c9 | 1239 | process_echoes(tty); |
1da177e4 LT |
1240 | return; |
1241 | } | |
1242 | if (c == '\n') { | |
acc71bba | 1243 | if (tty->read_cnt >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1244 | if (L_ECHO(tty)) |
1245 | process_output('\a', tty); | |
acc71bba JP |
1246 | return; |
1247 | } | |
1248 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
a88a69c9 JP |
1249 | echo_char_raw('\n', tty); |
1250 | process_echoes(tty); | |
1da177e4 LT |
1251 | } |
1252 | goto handle_newline; | |
1253 | } | |
1254 | if (c == EOF_CHAR(tty)) { | |
acc71bba JP |
1255 | if (tty->read_cnt >= N_TTY_BUF_SIZE) |
1256 | return; | |
4edf1827 AC |
1257 | if (tty->canon_head != tty->read_head) |
1258 | set_bit(TTY_PUSH, &tty->flags); | |
1da177e4 LT |
1259 | c = __DISABLED_CHAR; |
1260 | goto handle_newline; | |
1261 | } | |
1262 | if ((c == EOL_CHAR(tty)) || | |
1263 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1264 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1265 | ? 1 : 0; | |
1266 | if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) { | |
7e94b1d9 JP |
1267 | if (L_ECHO(tty)) |
1268 | process_output('\a', tty); | |
acc71bba JP |
1269 | return; |
1270 | } | |
1da177e4 LT |
1271 | /* |
1272 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1273 | */ | |
1274 | if (L_ECHO(tty)) { | |
1da177e4 LT |
1275 | /* Record the column of first canon char. */ |
1276 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1277 | echo_set_canon_col(tty); |
1da177e4 | 1278 | echo_char(c, tty); |
a88a69c9 | 1279 | process_echoes(tty); |
1da177e4 LT |
1280 | } |
1281 | /* | |
1282 | * XXX does PARMRK doubling happen for | |
1283 | * EOL_CHAR and EOL2_CHAR? | |
1284 | */ | |
acc71bba | 1285 | if (parmrk) |
1da177e4 LT |
1286 | put_tty_queue(c, tty); |
1287 | ||
4edf1827 | 1288 | handle_newline: |
1da177e4 LT |
1289 | spin_lock_irqsave(&tty->read_lock, flags); |
1290 | set_bit(tty->read_head, tty->read_flags); | |
1291 | put_tty_queue_nolock(c, tty); | |
1292 | tty->canon_head = tty->read_head; | |
1293 | tty->canon_data++; | |
1294 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1295 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); | |
1296 | if (waitqueue_active(&tty->read_wait)) | |
1297 | wake_up_interruptible(&tty->read_wait); | |
1298 | return; | |
1299 | } | |
1300 | } | |
4edf1827 | 1301 | |
acc71bba JP |
1302 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
1303 | if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { | |
1304 | /* beep if no space */ | |
7e94b1d9 JP |
1305 | if (L_ECHO(tty)) |
1306 | process_output('\a', tty); | |
acc71bba JP |
1307 | return; |
1308 | } | |
1309 | if (L_ECHO(tty)) { | |
1310 | finish_erasing(tty); | |
1da177e4 | 1311 | if (c == '\n') |
a88a69c9 | 1312 | echo_char_raw('\n', tty); |
1da177e4 LT |
1313 | else { |
1314 | /* Record the column of first canon char. */ | |
1315 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1316 | echo_set_canon_col(tty); |
1da177e4 LT |
1317 | echo_char(c, tty); |
1318 | } | |
a88a69c9 | 1319 | process_echoes(tty); |
1da177e4 LT |
1320 | } |
1321 | ||
acc71bba | 1322 | if (parmrk) |
1da177e4 LT |
1323 | put_tty_queue(c, tty); |
1324 | ||
1325 | put_tty_queue(c, tty); | |
4edf1827 | 1326 | } |
1da177e4 | 1327 | |
1da177e4 LT |
1328 | |
1329 | /** | |
1330 | * n_tty_write_wakeup - asynchronous I/O notifier | |
1331 | * @tty: tty device | |
1332 | * | |
1333 | * Required for the ptys, serial driver etc. since processes | |
1334 | * that attach themselves to the master and rely on ASYNC | |
1335 | * IO must be woken up | |
1336 | */ | |
1337 | ||
1338 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
1339 | { | |
ff8cb0fd | 1340 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) |
1da177e4 | 1341 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); |
1da177e4 LT |
1342 | } |
1343 | ||
1344 | /** | |
1345 | * n_tty_receive_buf - data receive | |
1346 | * @tty: terminal device | |
1347 | * @cp: buffer | |
1348 | * @fp: flag buffer | |
1349 | * @count: characters | |
1350 | * | |
1351 | * Called by the terminal driver when a block of characters has | |
1352 | * been received. This function must be called from soft contexts | |
1353 | * not from interrupt context. The driver is responsible for making | |
1354 | * calls one at a time and in order (or using flush_to_ldisc) | |
1355 | */ | |
4edf1827 | 1356 | |
1da177e4 LT |
1357 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1358 | char *fp, int count) | |
1359 | { | |
1360 | const unsigned char *p; | |
1361 | char *f, flags = TTY_NORMAL; | |
1362 | int i; | |
1363 | char buf[64]; | |
1364 | unsigned long cpuflags; | |
1365 | ||
1366 | if (!tty->read_buf) | |
1367 | return; | |
1368 | ||
1369 | if (tty->real_raw) { | |
1370 | spin_lock_irqsave(&tty->read_lock, cpuflags); | |
1371 | i = min(N_TTY_BUF_SIZE - tty->read_cnt, | |
1372 | N_TTY_BUF_SIZE - tty->read_head); | |
1373 | i = min(count, i); | |
1374 | memcpy(tty->read_buf + tty->read_head, cp, i); | |
1375 | tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1376 | tty->read_cnt += i; | |
1377 | cp += i; | |
1378 | count -= i; | |
1379 | ||
1380 | i = min(N_TTY_BUF_SIZE - tty->read_cnt, | |
1381 | N_TTY_BUF_SIZE - tty->read_head); | |
1382 | i = min(count, i); | |
1383 | memcpy(tty->read_buf + tty->read_head, cp, i); | |
1384 | tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1385 | tty->read_cnt += i; | |
1386 | spin_unlock_irqrestore(&tty->read_lock, cpuflags); | |
1387 | } else { | |
4edf1827 | 1388 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1389 | if (f) |
1390 | flags = *f++; | |
1391 | switch (flags) { | |
1392 | case TTY_NORMAL: | |
1393 | n_tty_receive_char(tty, *p); | |
1394 | break; | |
1395 | case TTY_BREAK: | |
1396 | n_tty_receive_break(tty); | |
1397 | break; | |
1398 | case TTY_PARITY: | |
1399 | case TTY_FRAME: | |
1400 | n_tty_receive_parity_error(tty, *p); | |
1401 | break; | |
1402 | case TTY_OVERRUN: | |
1403 | n_tty_receive_overrun(tty); | |
1404 | break; | |
1405 | default: | |
4edf1827 | 1406 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1407 | tty_name(tty, buf), flags); |
1408 | break; | |
1409 | } | |
1410 | } | |
f34d7a5b AC |
1411 | if (tty->ops->flush_chars) |
1412 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1413 | } |
1414 | ||
33f0f88f AC |
1415 | n_tty_set_room(tty); |
1416 | ||
26df6d13 | 1417 | if ((!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) || |
1418 | L_EXTPROC(tty)) { | |
1da177e4 LT |
1419 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1420 | if (waitqueue_active(&tty->read_wait)) | |
1421 | wake_up_interruptible(&tty->read_wait); | |
1422 | } | |
1423 | ||
1424 | /* | |
1425 | * Check the remaining room for the input canonicalization | |
1426 | * mode. We don't want to throttle the driver if we're in | |
1427 | * canonical mode and don't have a newline yet! | |
1428 | */ | |
39c2e60f AC |
1429 | if (tty->receive_room < TTY_THRESHOLD_THROTTLE) |
1430 | tty_throttle(tty); | |
1da177e4 LT |
1431 | } |
1432 | ||
1433 | int is_ignored(int sig) | |
1434 | { | |
1435 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1436 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1437 | } |
1438 | ||
1439 | /** | |
1440 | * n_tty_set_termios - termios data changed | |
1441 | * @tty: terminal | |
1442 | * @old: previous data | |
1443 | * | |
1444 | * Called by the tty layer when the user changes termios flags so | |
1445 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1446 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1447 | * guaranteed that this function will not be re-entered or in progress |
1448 | * when the ldisc is closed. | |
17b82060 AC |
1449 | * |
1450 | * Locking: Caller holds tty->termios_mutex | |
1da177e4 | 1451 | */ |
4edf1827 AC |
1452 | |
1453 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1454 | { |
47afa7a5 AC |
1455 | int canon_change = 1; |
1456 | BUG_ON(!tty); | |
1457 | ||
1458 | if (old) | |
1459 | canon_change = (old->c_lflag ^ tty->termios->c_lflag) & ICANON; | |
1460 | if (canon_change) { | |
1461 | memset(&tty->read_flags, 0, sizeof tty->read_flags); | |
1462 | tty->canon_head = tty->read_tail; | |
1463 | tty->canon_data = 0; | |
1464 | tty->erasing = 0; | |
1465 | } | |
1466 | ||
1467 | if (canon_change && !L_ICANON(tty) && tty->read_cnt) | |
1468 | wake_up_interruptible(&tty->read_wait); | |
4edf1827 | 1469 | |
1da177e4 LT |
1470 | tty->icanon = (L_ICANON(tty) != 0); |
1471 | if (test_bit(TTY_HW_COOK_IN, &tty->flags)) { | |
1472 | tty->raw = 1; | |
1473 | tty->real_raw = 1; | |
33f0f88f | 1474 | n_tty_set_room(tty); |
1da177e4 LT |
1475 | return; |
1476 | } | |
1477 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || | |
1478 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1479 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1480 | I_PARMRK(tty)) { | |
1481 | memset(tty->process_char_map, 0, 256/8); | |
1482 | ||
1483 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1484 | set_bit('\r', tty->process_char_map); | |
1485 | if (I_INLCR(tty)) | |
1486 | set_bit('\n', tty->process_char_map); | |
1487 | ||
1488 | if (L_ICANON(tty)) { | |
1489 | set_bit(ERASE_CHAR(tty), tty->process_char_map); | |
1490 | set_bit(KILL_CHAR(tty), tty->process_char_map); | |
1491 | set_bit(EOF_CHAR(tty), tty->process_char_map); | |
1492 | set_bit('\n', tty->process_char_map); | |
1493 | set_bit(EOL_CHAR(tty), tty->process_char_map); | |
1494 | if (L_IEXTEN(tty)) { | |
1495 | set_bit(WERASE_CHAR(tty), | |
1496 | tty->process_char_map); | |
1497 | set_bit(LNEXT_CHAR(tty), | |
1498 | tty->process_char_map); | |
1499 | set_bit(EOL2_CHAR(tty), | |
1500 | tty->process_char_map); | |
1501 | if (L_ECHO(tty)) | |
1502 | set_bit(REPRINT_CHAR(tty), | |
1503 | tty->process_char_map); | |
1504 | } | |
1505 | } | |
1506 | if (I_IXON(tty)) { | |
1507 | set_bit(START_CHAR(tty), tty->process_char_map); | |
1508 | set_bit(STOP_CHAR(tty), tty->process_char_map); | |
1509 | } | |
1510 | if (L_ISIG(tty)) { | |
1511 | set_bit(INTR_CHAR(tty), tty->process_char_map); | |
1512 | set_bit(QUIT_CHAR(tty), tty->process_char_map); | |
1513 | set_bit(SUSP_CHAR(tty), tty->process_char_map); | |
1514 | } | |
1515 | clear_bit(__DISABLED_CHAR, tty->process_char_map); | |
1516 | tty->raw = 0; | |
1517 | tty->real_raw = 0; | |
1518 | } else { | |
1519 | tty->raw = 1; | |
1520 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && | |
1521 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1522 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
1523 | tty->real_raw = 1; | |
1524 | else | |
1525 | tty->real_raw = 0; | |
1526 | } | |
33f0f88f | 1527 | n_tty_set_room(tty); |
f34d7a5b AC |
1528 | /* The termios change make the tty ready for I/O */ |
1529 | wake_up_interruptible(&tty->write_wait); | |
1530 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1531 | } |
1532 | ||
1533 | /** | |
1534 | * n_tty_close - close the ldisc for this tty | |
1535 | * @tty: device | |
1536 | * | |
4edf1827 AC |
1537 | * Called from the terminal layer when this line discipline is |
1538 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1539 | * discipline change. The function will not be called while other |
1540 | * ldisc methods are in progress. | |
1541 | */ | |
4edf1827 | 1542 | |
1da177e4 LT |
1543 | static void n_tty_close(struct tty_struct *tty) |
1544 | { | |
1545 | n_tty_flush_buffer(tty); | |
1546 | if (tty->read_buf) { | |
0b4068a1 | 1547 | kfree(tty->read_buf); |
1da177e4 LT |
1548 | tty->read_buf = NULL; |
1549 | } | |
a88a69c9 | 1550 | if (tty->echo_buf) { |
0b4068a1 | 1551 | kfree(tty->echo_buf); |
a88a69c9 JP |
1552 | tty->echo_buf = NULL; |
1553 | } | |
1da177e4 LT |
1554 | } |
1555 | ||
1556 | /** | |
1557 | * n_tty_open - open an ldisc | |
1558 | * @tty: terminal to open | |
1559 | * | |
4edf1827 | 1560 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1561 | * terminal device. Can sleep. Called serialized so that no |
1562 | * other events will occur in parallel. No further open will occur | |
1563 | * until a close. | |
1564 | */ | |
1565 | ||
1566 | static int n_tty_open(struct tty_struct *tty) | |
1567 | { | |
1568 | if (!tty) | |
1569 | return -EINVAL; | |
1570 | ||
a88a69c9 | 1571 | /* These are ugly. Currently a malloc failure here can panic */ |
1da177e4 | 1572 | if (!tty->read_buf) { |
0b4068a1 | 1573 | tty->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1da177e4 LT |
1574 | if (!tty->read_buf) |
1575 | return -ENOMEM; | |
1576 | } | |
a88a69c9 | 1577 | if (!tty->echo_buf) { |
0b4068a1 AC |
1578 | tty->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1579 | ||
a88a69c9 JP |
1580 | if (!tty->echo_buf) |
1581 | return -ENOMEM; | |
1582 | } | |
1da177e4 LT |
1583 | reset_buffer_flags(tty); |
1584 | tty->column = 0; | |
1585 | n_tty_set_termios(tty, NULL); | |
1586 | tty->minimum_to_wake = 1; | |
1587 | tty->closing = 0; | |
1588 | return 0; | |
1589 | } | |
1590 | ||
1591 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1592 | { | |
e043e42b | 1593 | tty_flush_to_ldisc(tty); |
26df6d13 | 1594 | if (tty->icanon && !L_EXTPROC(tty)) { |
1da177e4 LT |
1595 | if (tty->canon_data) |
1596 | return 1; | |
1597 | } else if (tty->read_cnt >= (amt ? amt : 1)) | |
1598 | return 1; | |
1599 | ||
1600 | return 0; | |
1601 | } | |
1602 | ||
1603 | /** | |
1604 | * copy_from_read_buf - copy read data directly | |
1605 | * @tty: terminal device | |
1606 | * @b: user data | |
1607 | * @nr: size of data | |
1608 | * | |
11a96d18 | 1609 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1610 | * ICANON is off; it copies characters straight from the tty queue to |
1611 | * user space directly. It can be profitably called twice; once to | |
1612 | * drain the space from the tail pointer to the (physical) end of the | |
1613 | * buffer, and once to drain the space from the (physical) beginning of | |
1614 | * the buffer to head pointer. | |
1615 | * | |
817d6d3b | 1616 | * Called under the tty->atomic_read_lock sem |
1da177e4 LT |
1617 | * |
1618 | */ | |
4edf1827 | 1619 | |
33f0f88f | 1620 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1621 | unsigned char __user **b, |
1622 | size_t *nr) | |
1623 | ||
1624 | { | |
1625 | int retval; | |
1626 | size_t n; | |
1627 | unsigned long flags; | |
1628 | ||
1629 | retval = 0; | |
1630 | spin_lock_irqsave(&tty->read_lock, flags); | |
1631 | n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail); | |
1632 | n = min(*nr, n); | |
1633 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1634 | if (n) { | |
1da177e4 LT |
1635 | retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n); |
1636 | n -= retval; | |
522ed776 | 1637 | tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n); |
1da177e4 LT |
1638 | spin_lock_irqsave(&tty->read_lock, flags); |
1639 | tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1); | |
1640 | tty->read_cnt -= n; | |
26df6d13 | 1641 | /* Turn single EOF into zero-length read */ |
1642 | if (L_EXTPROC(tty) && tty->icanon && n == 1) { | |
1643 | if (!tty->read_cnt && (*b)[n-1] == EOF_CHAR(tty)) | |
1644 | n--; | |
1645 | } | |
1da177e4 LT |
1646 | spin_unlock_irqrestore(&tty->read_lock, flags); |
1647 | *b += n; | |
1648 | *nr -= n; | |
1649 | } | |
1650 | return retval; | |
1651 | } | |
1652 | ||
cc4191dc | 1653 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1654 | size_t, loff_t *); |
1da177e4 LT |
1655 | |
1656 | /** | |
1657 | * job_control - check job control | |
1658 | * @tty: tty | |
1659 | * @file: file handle | |
1660 | * | |
1661 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1662 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1663 | * error code if action should be taken. |
04f378b1 AC |
1664 | * |
1665 | * FIXME: | |
1666 | * Locking: None - redirected write test is safe, testing | |
1667 | * current->signal should possibly lock current->sighand | |
1668 | * pgrp locking ? | |
1da177e4 | 1669 | */ |
4edf1827 | 1670 | |
1da177e4 LT |
1671 | static int job_control(struct tty_struct *tty, struct file *file) |
1672 | { | |
1673 | /* Job control check -- must be done at start and after | |
1674 | every sleep (POSIX.1 7.1.1.4). */ | |
1675 | /* NOTE: not yet done after every sleep pending a thorough | |
1676 | check of the logic of this change. -- jlc */ | |
1677 | /* don't stop on /dev/console */ | |
1678 | if (file->f_op->write != redirected_tty_write && | |
1679 | current->signal->tty == tty) { | |
ab521dc0 | 1680 | if (!tty->pgrp) |
11a96d18 | 1681 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); |
ab521dc0 | 1682 | else if (task_pgrp(current) != tty->pgrp) { |
1da177e4 | 1683 | if (is_ignored(SIGTTIN) || |
3e7cd6c4 | 1684 | is_current_pgrp_orphaned()) |
1da177e4 | 1685 | return -EIO; |
ab521dc0 | 1686 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); |
040b6362 | 1687 | set_thread_flag(TIF_SIGPENDING); |
1da177e4 LT |
1688 | return -ERESTARTSYS; |
1689 | } | |
1690 | } | |
1691 | return 0; | |
1692 | } | |
4edf1827 | 1693 | |
1da177e4 LT |
1694 | |
1695 | /** | |
11a96d18 | 1696 | * n_tty_read - read function for tty |
1da177e4 LT |
1697 | * @tty: tty device |
1698 | * @file: file object | |
1699 | * @buf: userspace buffer pointer | |
1700 | * @nr: size of I/O | |
1701 | * | |
1702 | * Perform reads for the line discipline. We are guaranteed that the | |
1703 | * line discipline will not be closed under us but we may get multiple | |
1704 | * parallel readers and must handle this ourselves. We may also get | |
1705 | * a hangup. Always called in user context, may sleep. | |
1706 | * | |
1707 | * This code must be sure never to sleep through a hangup. | |
1708 | */ | |
4edf1827 | 1709 | |
11a96d18 | 1710 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1711 | unsigned char __user *buf, size_t nr) |
1712 | { | |
1713 | unsigned char __user *b = buf; | |
1714 | DECLARE_WAITQUEUE(wait, current); | |
1715 | int c; | |
1716 | int minimum, time; | |
1717 | ssize_t retval = 0; | |
1718 | ssize_t size; | |
1719 | long timeout; | |
1720 | unsigned long flags; | |
04f378b1 | 1721 | int packet; |
1da177e4 LT |
1722 | |
1723 | do_it_again: | |
1724 | ||
17b82060 | 1725 | BUG_ON(!tty->read_buf); |
1da177e4 LT |
1726 | |
1727 | c = job_control(tty, file); | |
4edf1827 | 1728 | if (c < 0) |
1da177e4 | 1729 | return c; |
4edf1827 | 1730 | |
1da177e4 LT |
1731 | minimum = time = 0; |
1732 | timeout = MAX_SCHEDULE_TIMEOUT; | |
1733 | if (!tty->icanon) { | |
1734 | time = (HZ / 10) * TIME_CHAR(tty); | |
1735 | minimum = MIN_CHAR(tty); | |
1736 | if (minimum) { | |
1737 | if (time) | |
1738 | tty->minimum_to_wake = 1; | |
1739 | else if (!waitqueue_active(&tty->read_wait) || | |
1740 | (tty->minimum_to_wake > minimum)) | |
1741 | tty->minimum_to_wake = minimum; | |
1742 | } else { | |
1743 | timeout = 0; | |
1744 | if (time) { | |
1745 | timeout = time; | |
1746 | time = 0; | |
1747 | } | |
1748 | tty->minimum_to_wake = minimum = 1; | |
1749 | } | |
1750 | } | |
1751 | ||
1752 | /* | |
1753 | * Internal serialization of reads. | |
1754 | */ | |
1755 | if (file->f_flags & O_NONBLOCK) { | |
70522e12 | 1756 | if (!mutex_trylock(&tty->atomic_read_lock)) |
1da177e4 | 1757 | return -EAGAIN; |
4edf1827 | 1758 | } else { |
70522e12 | 1759 | if (mutex_lock_interruptible(&tty->atomic_read_lock)) |
1da177e4 LT |
1760 | return -ERESTARTSYS; |
1761 | } | |
04f378b1 | 1762 | packet = tty->packet; |
1da177e4 LT |
1763 | |
1764 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
1765 | while (nr) { |
1766 | /* First test for status change. */ | |
04f378b1 | 1767 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
1768 | unsigned char cs; |
1769 | if (b != buf) | |
1770 | break; | |
04f378b1 | 1771 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
1772 | cs = tty->link->ctrl_status; |
1773 | tty->link->ctrl_status = 0; | |
04f378b1 | 1774 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 1775 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
1776 | retval = -EFAULT; |
1777 | b--; | |
1778 | break; | |
1779 | } | |
1780 | nr--; | |
1781 | break; | |
1782 | } | |
1783 | /* This statement must be first before checking for input | |
1784 | so that any interrupt will set the state back to | |
1785 | TASK_RUNNING. */ | |
1786 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 1787 | |
1da177e4 LT |
1788 | if (((minimum - (b - buf)) < tty->minimum_to_wake) && |
1789 | ((minimum - (b - buf)) >= 1)) | |
1790 | tty->minimum_to_wake = (minimum - (b - buf)); | |
4edf1827 | 1791 | |
1da177e4 LT |
1792 | if (!input_available_p(tty, 0)) { |
1793 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
1794 | retval = -EIO; | |
1795 | break; | |
1796 | } | |
1797 | if (tty_hung_up_p(file)) | |
1798 | break; | |
1799 | if (!timeout) | |
1800 | break; | |
1801 | if (file->f_flags & O_NONBLOCK) { | |
1802 | retval = -EAGAIN; | |
1803 | break; | |
1804 | } | |
1805 | if (signal_pending(current)) { | |
1806 | retval = -ERESTARTSYS; | |
1807 | break; | |
1808 | } | |
04f378b1 | 1809 | /* FIXME: does n_tty_set_room need locking ? */ |
33f0f88f | 1810 | n_tty_set_room(tty); |
1da177e4 | 1811 | timeout = schedule_timeout(timeout); |
1da177e4 LT |
1812 | continue; |
1813 | } | |
1814 | __set_current_state(TASK_RUNNING); | |
1815 | ||
1816 | /* Deal with packet mode. */ | |
04f378b1 | 1817 | if (packet && b == buf) { |
522ed776 | 1818 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
1819 | retval = -EFAULT; |
1820 | b--; | |
1821 | break; | |
1822 | } | |
1823 | nr--; | |
1824 | } | |
1825 | ||
26df6d13 | 1826 | if (tty->icanon && !L_EXTPROC(tty)) { |
1da177e4 LT |
1827 | /* N.B. avoid overrun if nr == 0 */ |
1828 | while (nr && tty->read_cnt) { | |
4edf1827 | 1829 | int eol; |
1da177e4 LT |
1830 | |
1831 | eol = test_and_clear_bit(tty->read_tail, | |
1832 | tty->read_flags); | |
1833 | c = tty->read_buf[tty->read_tail]; | |
1834 | spin_lock_irqsave(&tty->read_lock, flags); | |
1835 | tty->read_tail = ((tty->read_tail+1) & | |
1836 | (N_TTY_BUF_SIZE-1)); | |
1837 | tty->read_cnt--; | |
1838 | if (eol) { | |
1839 | /* this test should be redundant: | |
1840 | * we shouldn't be reading data if | |
1841 | * canon_data is 0 | |
1842 | */ | |
1843 | if (--tty->canon_data < 0) | |
1844 | tty->canon_data = 0; | |
1845 | } | |
1846 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1847 | ||
1848 | if (!eol || (c != __DISABLED_CHAR)) { | |
522ed776 | 1849 | if (tty_put_user(tty, c, b++)) { |
1da177e4 LT |
1850 | retval = -EFAULT; |
1851 | b--; | |
1852 | break; | |
1853 | } | |
1854 | nr--; | |
1855 | } | |
522ed776 MT |
1856 | if (eol) { |
1857 | tty_audit_push(tty); | |
1da177e4 | 1858 | break; |
522ed776 | 1859 | } |
1da177e4 LT |
1860 | } |
1861 | if (retval) | |
1862 | break; | |
1863 | } else { | |
1864 | int uncopied; | |
04f378b1 AC |
1865 | /* The copy function takes the read lock and handles |
1866 | locking internally for this case */ | |
1da177e4 LT |
1867 | uncopied = copy_from_read_buf(tty, &b, &nr); |
1868 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
1869 | if (uncopied) { | |
1870 | retval = -EFAULT; | |
1871 | break; | |
1872 | } | |
1873 | } | |
1874 | ||
1875 | /* If there is enough space in the read buffer now, let the | |
1876 | * low-level driver know. We use n_tty_chars_in_buffer() to | |
1877 | * check the buffer, as it now knows about canonical mode. | |
1878 | * Otherwise, if the driver is throttled and the line is | |
1879 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
1880 | * we won't get any more characters. | |
1881 | */ | |
289a1e99 PM |
1882 | if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) { |
1883 | n_tty_set_room(tty); | |
1da177e4 | 1884 | check_unthrottle(tty); |
289a1e99 | 1885 | } |
1da177e4 LT |
1886 | |
1887 | if (b - buf >= minimum) | |
1888 | break; | |
1889 | if (time) | |
1890 | timeout = time; | |
1891 | } | |
70522e12 | 1892 | mutex_unlock(&tty->atomic_read_lock); |
1da177e4 LT |
1893 | remove_wait_queue(&tty->read_wait, &wait); |
1894 | ||
1895 | if (!waitqueue_active(&tty->read_wait)) | |
1896 | tty->minimum_to_wake = minimum; | |
1897 | ||
1898 | __set_current_state(TASK_RUNNING); | |
1899 | size = b - buf; | |
1900 | if (size) { | |
1901 | retval = size; | |
1902 | if (nr) | |
4edf1827 | 1903 | clear_bit(TTY_PUSH, &tty->flags); |
1da177e4 LT |
1904 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) |
1905 | goto do_it_again; | |
1906 | ||
33f0f88f | 1907 | n_tty_set_room(tty); |
1da177e4 LT |
1908 | return retval; |
1909 | } | |
1910 | ||
1911 | /** | |
11a96d18 | 1912 | * n_tty_write - write function for tty |
1da177e4 LT |
1913 | * @tty: tty device |
1914 | * @file: file object | |
1915 | * @buf: userspace buffer pointer | |
1916 | * @nr: size of I/O | |
1917 | * | |
a88a69c9 | 1918 | * Write function of the terminal device. This is serialized with |
1da177e4 | 1919 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
1920 | * and other such events. Since the receive code will echo characters, |
1921 | * thus calling driver write methods, the output_lock is used in | |
1922 | * the output processing functions called here as well as in the | |
1923 | * echo processing function to protect the column state and space | |
1924 | * left in the buffer. | |
1da177e4 LT |
1925 | * |
1926 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
1927 | * |
1928 | * Locking: output_lock to protect column state and space left | |
1929 | * (note that the process_output*() functions take this | |
1930 | * lock themselves) | |
1da177e4 | 1931 | */ |
4edf1827 | 1932 | |
11a96d18 | 1933 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 1934 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
1935 | { |
1936 | const unsigned char *b = buf; | |
1937 | DECLARE_WAITQUEUE(wait, current); | |
1938 | int c; | |
1939 | ssize_t retval = 0; | |
1940 | ||
1941 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
1942 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
1943 | retval = tty_check_change(tty); | |
1944 | if (retval) | |
1945 | return retval; | |
1946 | } | |
1947 | ||
a88a69c9 JP |
1948 | /* Write out any echoed characters that are still pending */ |
1949 | process_echoes(tty); | |
300a6204 | 1950 | |
1da177e4 LT |
1951 | add_wait_queue(&tty->write_wait, &wait); |
1952 | while (1) { | |
1953 | set_current_state(TASK_INTERRUPTIBLE); | |
1954 | if (signal_pending(current)) { | |
1955 | retval = -ERESTARTSYS; | |
1956 | break; | |
1957 | } | |
1958 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
1959 | retval = -EIO; | |
1960 | break; | |
1961 | } | |
1962 | if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
1963 | while (nr > 0) { | |
a88a69c9 | 1964 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
1965 | if (num < 0) { |
1966 | if (num == -EAGAIN) | |
1967 | break; | |
1968 | retval = num; | |
1969 | goto break_out; | |
1970 | } | |
1971 | b += num; | |
1972 | nr -= num; | |
1973 | if (nr == 0) | |
1974 | break; | |
1975 | c = *b; | |
a88a69c9 | 1976 | if (process_output(c, tty) < 0) |
1da177e4 LT |
1977 | break; |
1978 | b++; nr--; | |
1979 | } | |
f34d7a5b AC |
1980 | if (tty->ops->flush_chars) |
1981 | tty->ops->flush_chars(tty); | |
1da177e4 | 1982 | } else { |
d6afe27b | 1983 | while (nr > 0) { |
f34d7a5b | 1984 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
1985 | if (c < 0) { |
1986 | retval = c; | |
1987 | goto break_out; | |
1988 | } | |
1989 | if (!c) | |
1990 | break; | |
1991 | b += c; | |
1992 | nr -= c; | |
1da177e4 | 1993 | } |
1da177e4 LT |
1994 | } |
1995 | if (!nr) | |
1996 | break; | |
1997 | if (file->f_flags & O_NONBLOCK) { | |
1998 | retval = -EAGAIN; | |
1999 | break; | |
2000 | } | |
2001 | schedule(); | |
2002 | } | |
2003 | break_out: | |
2004 | __set_current_state(TASK_RUNNING); | |
2005 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2006 | if (b - buf != nr && tty->fasync) |
2007 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
1da177e4 LT |
2008 | return (b - buf) ? b - buf : retval; |
2009 | } | |
2010 | ||
2011 | /** | |
11a96d18 | 2012 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2013 | * @tty: terminal device |
2014 | * @file: file accessing it | |
2015 | * @wait: poll table | |
2016 | * | |
2017 | * Called when the line discipline is asked to poll() for data or | |
2018 | * for special events. This code is not serialized with respect to | |
2019 | * other events save open/close. | |
2020 | * | |
2021 | * This code must be sure never to sleep through a hangup. | |
2022 | * Called without the kernel lock held - fine | |
1da177e4 | 2023 | */ |
4edf1827 | 2024 | |
11a96d18 | 2025 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2026 | poll_table *wait) |
1da177e4 LT |
2027 | { |
2028 | unsigned int mask = 0; | |
2029 | ||
2030 | poll_wait(file, &tty->read_wait, wait); | |
2031 | poll_wait(file, &tty->write_wait, wait); | |
2032 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2033 | mask |= POLLIN | POLLRDNORM; | |
2034 | if (tty->packet && tty->link->ctrl_status) | |
2035 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2036 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2037 | mask |= POLLHUP; | |
2038 | if (tty_hung_up_p(file)) | |
2039 | mask |= POLLHUP; | |
2040 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2041 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
2042 | tty->minimum_to_wake = MIN_CHAR(tty); | |
2043 | else | |
2044 | tty->minimum_to_wake = 1; | |
2045 | } | |
f34d7a5b AC |
2046 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2047 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2048 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2049 | mask |= POLLOUT | POLLWRNORM; |
2050 | return mask; | |
2051 | } | |
2052 | ||
47afa7a5 AC |
2053 | static unsigned long inq_canon(struct tty_struct *tty) |
2054 | { | |
2055 | int nr, head, tail; | |
2056 | ||
17b82060 | 2057 | if (!tty->canon_data) |
47afa7a5 AC |
2058 | return 0; |
2059 | head = tty->canon_head; | |
2060 | tail = tty->read_tail; | |
2061 | nr = (head - tail) & (N_TTY_BUF_SIZE-1); | |
2062 | /* Skip EOF-chars.. */ | |
2063 | while (head != tail) { | |
2064 | if (test_bit(tail, tty->read_flags) && | |
2065 | tty->read_buf[tail] == __DISABLED_CHAR) | |
2066 | nr--; | |
2067 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
2068 | } | |
2069 | return nr; | |
2070 | } | |
2071 | ||
2072 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2073 | unsigned int cmd, unsigned long arg) | |
2074 | { | |
2075 | int retval; | |
2076 | ||
2077 | switch (cmd) { | |
2078 | case TIOCOUTQ: | |
2079 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2080 | case TIOCINQ: | |
17b82060 | 2081 | /* FIXME: Locking */ |
47afa7a5 AC |
2082 | retval = tty->read_cnt; |
2083 | if (L_ICANON(tty)) | |
2084 | retval = inq_canon(tty); | |
2085 | return put_user(retval, (unsigned int __user *) arg); | |
2086 | default: | |
2087 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2088 | } | |
2089 | } | |
2090 | ||
a352def2 | 2091 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2092 | .magic = TTY_LDISC_MAGIC, |
2093 | .name = "n_tty", | |
2094 | .open = n_tty_open, | |
2095 | .close = n_tty_close, | |
2096 | .flush_buffer = n_tty_flush_buffer, | |
2097 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2098 | .read = n_tty_read, |
2099 | .write = n_tty_write, | |
e10cc1df PF |
2100 | .ioctl = n_tty_ioctl, |
2101 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2102 | .poll = n_tty_poll, |
e10cc1df PF |
2103 | .receive_buf = n_tty_receive_buf, |
2104 | .write_wakeup = n_tty_write_wakeup | |
1da177e4 | 2105 | }; |
572b9adb RG |
2106 | |
2107 | /** | |
2108 | * n_tty_inherit_ops - inherit N_TTY methods | |
2109 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2110 | * | |
2111 | * Used by a generic struct tty_ldisc_ops to easily inherit N_TTY | |
2112 | * methods. | |
2113 | */ | |
2114 | ||
2115 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2116 | { | |
2117 | *ops = tty_ldisc_N_TTY; | |
2118 | ops->owner = NULL; | |
2119 | ops->refcount = ops->flags = 0; | |
2120 | } | |
2121 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |