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 */ | |
bbd20759 | 64 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
1da177e4 | 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 | ||
55db4c64 LT |
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 | { | |
96 | /* tty->read_cnt is not read locked ? */ | |
97 | int left = N_TTY_BUF_SIZE - tty->read_cnt - 1; | |
98 | int old_left; | |
99 | ||
100 | /* | |
101 | * If we are doing input canonicalization, and there are no | |
102 | * pending newlines, let characters through without limit, so | |
103 | * that erase characters will be handled. Other excess | |
104 | * characters will be beeped. | |
105 | */ | |
106 | if (left <= 0) | |
107 | left = tty->icanon && !tty->canon_data; | |
108 | old_left = tty->receive_room; | |
109 | tty->receive_room = left; | |
110 | ||
111 | /* Did this open up the receive buffer? We may need to flip */ | |
112 | if (left && !old_left) | |
113 | schedule_work(&tty->buf.work); | |
114 | } | |
115 | ||
33f0f88f | 116 | static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty) |
1da177e4 LT |
117 | { |
118 | if (tty->read_cnt < N_TTY_BUF_SIZE) { | |
119 | tty->read_buf[tty->read_head] = c; | |
120 | tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1); | |
121 | tty->read_cnt++; | |
122 | } | |
123 | } | |
124 | ||
17b82060 AC |
125 | /** |
126 | * put_tty_queue - add character to tty | |
127 | * @c: character | |
128 | * @tty: tty device | |
129 | * | |
130 | * Add a character to the tty read_buf queue. This is done under the | |
131 | * read_lock to serialize character addition and also to protect us | |
132 | * against parallel reads or flushes | |
133 | */ | |
134 | ||
33f0f88f | 135 | static void put_tty_queue(unsigned char c, struct tty_struct *tty) |
1da177e4 LT |
136 | { |
137 | unsigned long flags; | |
138 | /* | |
139 | * The problem of stomping on the buffers ends here. | |
140 | * Why didn't anyone see this one coming? --AJK | |
141 | */ | |
142 | spin_lock_irqsave(&tty->read_lock, flags); | |
143 | put_tty_queue_nolock(c, tty); | |
144 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
145 | } | |
146 | ||
147 | /** | |
148 | * check_unthrottle - allow new receive data | |
149 | * @tty; tty device | |
150 | * | |
17b82060 AC |
151 | * Check whether to call the driver unthrottle functions |
152 | * | |
70522e12 | 153 | * Can sleep, may be called under the atomic_read_lock mutex but |
1da177e4 LT |
154 | * this is not guaranteed. |
155 | */ | |
4edf1827 | 156 | static void check_unthrottle(struct tty_struct *tty) |
1da177e4 | 157 | { |
39c2e60f AC |
158 | if (tty->count) |
159 | tty_unthrottle(tty); | |
1da177e4 LT |
160 | } |
161 | ||
162 | /** | |
163 | * reset_buffer_flags - reset buffer state | |
164 | * @tty: terminal to reset | |
165 | * | |
4edf1827 | 166 | * Reset the read buffer counters, clear the flags, |
1da177e4 LT |
167 | * and make sure the driver is unthrottled. Called |
168 | * from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 AC |
169 | * |
170 | * Locking: tty_read_lock for read fields. | |
1da177e4 | 171 | */ |
a88a69c9 | 172 | |
1da177e4 LT |
173 | static void reset_buffer_flags(struct tty_struct *tty) |
174 | { | |
175 | unsigned long flags; | |
176 | ||
177 | spin_lock_irqsave(&tty->read_lock, flags); | |
178 | tty->read_head = tty->read_tail = tty->read_cnt = 0; | |
179 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
a88a69c9 JP |
180 | |
181 | mutex_lock(&tty->echo_lock); | |
182 | tty->echo_pos = tty->echo_cnt = tty->echo_overrun = 0; | |
183 | mutex_unlock(&tty->echo_lock); | |
184 | ||
1da177e4 LT |
185 | tty->canon_head = tty->canon_data = tty->erasing = 0; |
186 | memset(&tty->read_flags, 0, sizeof tty->read_flags); | |
55db4c64 | 187 | n_tty_set_room(tty); |
1da177e4 LT |
188 | } |
189 | ||
190 | /** | |
191 | * n_tty_flush_buffer - clean input queue | |
192 | * @tty: terminal device | |
193 | * | |
194 | * Flush the input buffer. Called when the line discipline is | |
195 | * being closed, when the tty layer wants the buffer flushed (eg | |
196 | * at hangup) or when the N_TTY line discipline internally has to | |
197 | * clean the pending queue (for example some signals). | |
198 | * | |
17b82060 | 199 | * Locking: ctrl_lock, read_lock. |
1da177e4 | 200 | */ |
4edf1827 AC |
201 | |
202 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 203 | { |
04f378b1 | 204 | unsigned long flags; |
1da177e4 LT |
205 | /* clear everything and unthrottle the driver */ |
206 | reset_buffer_flags(tty); | |
4edf1827 | 207 | |
1da177e4 LT |
208 | if (!tty->link) |
209 | return; | |
210 | ||
04f378b1 | 211 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
1da177e4 LT |
212 | if (tty->link->packet) { |
213 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
214 | wake_up_interruptible(&tty->link->read_wait); | |
215 | } | |
04f378b1 | 216 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1da177e4 LT |
217 | } |
218 | ||
219 | /** | |
220 | * n_tty_chars_in_buffer - report available bytes | |
221 | * @tty: tty device | |
222 | * | |
223 | * Report the number of characters buffered to be delivered to user | |
4edf1827 | 224 | * at this instant in time. |
17b82060 AC |
225 | * |
226 | * Locking: read_lock | |
1da177e4 | 227 | */ |
4edf1827 | 228 | |
1da177e4 LT |
229 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
230 | { | |
231 | unsigned long flags; | |
232 | ssize_t n = 0; | |
233 | ||
234 | spin_lock_irqsave(&tty->read_lock, flags); | |
235 | if (!tty->icanon) { | |
236 | n = tty->read_cnt; | |
237 | } else if (tty->canon_data) { | |
238 | n = (tty->canon_head > tty->read_tail) ? | |
239 | tty->canon_head - tty->read_tail : | |
240 | tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail); | |
241 | } | |
242 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
243 | return n; | |
244 | } | |
245 | ||
246 | /** | |
247 | * is_utf8_continuation - utf8 multibyte check | |
248 | * @c: byte to check | |
249 | * | |
250 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
251 | * character. We use this to correctly compute the on screen size | |
252 | * of the character when printing | |
253 | */ | |
4edf1827 | 254 | |
1da177e4 LT |
255 | static inline int is_utf8_continuation(unsigned char c) |
256 | { | |
257 | return (c & 0xc0) == 0x80; | |
258 | } | |
259 | ||
260 | /** | |
261 | * is_continuation - multibyte check | |
262 | * @c: byte to check | |
263 | * | |
264 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
265 | * character and the terminal is in unicode mode. | |
266 | */ | |
4edf1827 | 267 | |
1da177e4 LT |
268 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
269 | { | |
270 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
271 | } | |
272 | ||
273 | /** | |
a88a69c9 | 274 | * do_output_char - output one character |
1da177e4 LT |
275 | * @c: character (or partial unicode symbol) |
276 | * @tty: terminal device | |
a88a69c9 | 277 | * @space: space available in tty driver write buffer |
1da177e4 | 278 | * |
a88a69c9 JP |
279 | * This is a helper function that handles one output character |
280 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
281 | * doing OPOST processing and putting the results in the |
282 | * tty driver's write buffer. | |
a88a69c9 JP |
283 | * |
284 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
285 | * and NLDLY. They simply aren't relevant in the world today. | |
286 | * If you ever need them, add them here. | |
1da177e4 | 287 | * |
a88a69c9 JP |
288 | * Returns the number of bytes of buffer space used or -1 if |
289 | * no space left. | |
290 | * | |
291 | * Locking: should be called under the output_lock to protect | |
292 | * the column state and space left in the buffer | |
1da177e4 | 293 | */ |
4edf1827 | 294 | |
a88a69c9 | 295 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 296 | { |
a88a69c9 | 297 | int spaces; |
1da177e4 | 298 | |
1da177e4 LT |
299 | if (!space) |
300 | return -1; | |
300a6204 | 301 | |
a88a69c9 JP |
302 | switch (c) { |
303 | case '\n': | |
304 | if (O_ONLRET(tty)) | |
305 | tty->column = 0; | |
306 | if (O_ONLCR(tty)) { | |
307 | if (space < 2) | |
308 | return -1; | |
1da177e4 | 309 | tty->canon_column = tty->column = 0; |
37f81fa1 | 310 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
311 | return 2; |
312 | } | |
313 | tty->canon_column = tty->column; | |
314 | break; | |
315 | case '\r': | |
316 | if (O_ONOCR(tty) && tty->column == 0) | |
317 | return 0; | |
318 | if (O_OCRNL(tty)) { | |
319 | c = '\n'; | |
320 | if (O_ONLRET(tty)) | |
321 | tty->canon_column = tty->column = 0; | |
1da177e4 | 322 | break; |
a88a69c9 JP |
323 | } |
324 | tty->canon_column = tty->column = 0; | |
325 | break; | |
326 | case '\t': | |
327 | spaces = 8 - (tty->column & 7); | |
328 | if (O_TABDLY(tty) == XTABS) { | |
329 | if (space < spaces) | |
330 | return -1; | |
1da177e4 | 331 | tty->column += spaces; |
a88a69c9 JP |
332 | tty->ops->write(tty, " ", spaces); |
333 | return spaces; | |
1da177e4 | 334 | } |
a88a69c9 JP |
335 | tty->column += spaces; |
336 | break; | |
337 | case '\b': | |
338 | if (tty->column > 0) | |
339 | tty->column--; | |
340 | break; | |
341 | default: | |
a59c0d6f JP |
342 | if (!iscntrl(c)) { |
343 | if (O_OLCUC(tty)) | |
344 | c = toupper(c); | |
345 | if (!is_continuation(c, tty)) | |
346 | tty->column++; | |
347 | } | |
a88a69c9 | 348 | break; |
1da177e4 | 349 | } |
a88a69c9 | 350 | |
f34d7a5b | 351 | tty_put_char(tty, c); |
a88a69c9 JP |
352 | return 1; |
353 | } | |
354 | ||
355 | /** | |
356 | * process_output - output post processor | |
357 | * @c: character (or partial unicode symbol) | |
358 | * @tty: terminal device | |
359 | * | |
ee5aa7b8 JP |
360 | * Output one character with OPOST processing. |
361 | * Returns -1 when the output device is full and the character | |
362 | * must be retried. | |
a88a69c9 JP |
363 | * |
364 | * Locking: output_lock to protect column state and space left | |
365 | * (also, this is called from n_tty_write under the | |
366 | * tty layer write lock) | |
367 | */ | |
368 | ||
369 | static int process_output(unsigned char c, struct tty_struct *tty) | |
370 | { | |
371 | int space, retval; | |
372 | ||
373 | mutex_lock(&tty->output_lock); | |
374 | ||
375 | space = tty_write_room(tty); | |
376 | retval = do_output_char(c, tty, space); | |
377 | ||
378 | mutex_unlock(&tty->output_lock); | |
379 | if (retval < 0) | |
380 | return -1; | |
381 | else | |
382 | return 0; | |
1da177e4 LT |
383 | } |
384 | ||
385 | /** | |
a88a69c9 | 386 | * process_output_block - block post processor |
1da177e4 | 387 | * @tty: terminal device |
ee5aa7b8 JP |
388 | * @buf: character buffer |
389 | * @nr: number of bytes to output | |
390 | * | |
391 | * Output a block of characters with OPOST processing. | |
392 | * Returns the number of characters output. | |
1da177e4 LT |
393 | * |
394 | * This path is used to speed up block console writes, among other | |
395 | * things when processing blocks of output data. It handles only | |
396 | * the simple cases normally found and helps to generate blocks of | |
397 | * symbols for the console driver and thus improve performance. | |
398 | * | |
a88a69c9 JP |
399 | * Locking: output_lock to protect column state and space left |
400 | * (also, this is called from n_tty_write under the | |
401 | * tty layer write lock) | |
1da177e4 | 402 | */ |
4edf1827 | 403 | |
a88a69c9 JP |
404 | static ssize_t process_output_block(struct tty_struct *tty, |
405 | const unsigned char *buf, unsigned int nr) | |
1da177e4 LT |
406 | { |
407 | int space; | |
bbd20759 | 408 | int i; |
1da177e4 LT |
409 | const unsigned char *cp; |
410 | ||
a88a69c9 JP |
411 | mutex_lock(&tty->output_lock); |
412 | ||
f34d7a5b | 413 | space = tty_write_room(tty); |
300a6204 | 414 | if (!space) { |
a88a69c9 | 415 | mutex_unlock(&tty->output_lock); |
1da177e4 | 416 | return 0; |
a88a69c9 | 417 | } |
1da177e4 LT |
418 | if (nr > space) |
419 | nr = space; | |
420 | ||
421 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
422 | unsigned char c = *cp; |
423 | ||
424 | switch (c) { | |
1da177e4 LT |
425 | case '\n': |
426 | if (O_ONLRET(tty)) | |
427 | tty->column = 0; | |
428 | if (O_ONLCR(tty)) | |
429 | goto break_out; | |
430 | tty->canon_column = tty->column; | |
431 | break; | |
432 | case '\r': | |
433 | if (O_ONOCR(tty) && tty->column == 0) | |
434 | goto break_out; | |
435 | if (O_OCRNL(tty)) | |
436 | goto break_out; | |
437 | tty->canon_column = tty->column = 0; | |
438 | break; | |
439 | case '\t': | |
440 | goto break_out; | |
441 | case '\b': | |
442 | if (tty->column > 0) | |
443 | tty->column--; | |
444 | break; | |
445 | default: | |
a59c0d6f JP |
446 | if (!iscntrl(c)) { |
447 | if (O_OLCUC(tty)) | |
448 | goto break_out; | |
449 | if (!is_continuation(c, tty)) | |
450 | tty->column++; | |
451 | } | |
1da177e4 LT |
452 | break; |
453 | } | |
454 | } | |
455 | break_out: | |
f34d7a5b | 456 | i = tty->ops->write(tty, buf, i); |
a88a69c9 JP |
457 | |
458 | mutex_unlock(&tty->output_lock); | |
1da177e4 LT |
459 | return i; |
460 | } | |
461 | ||
a88a69c9 JP |
462 | /** |
463 | * process_echoes - write pending echo characters | |
464 | * @tty: terminal device | |
465 | * | |
466 | * Write previously buffered echo (and other ldisc-generated) | |
467 | * characters to the tty. | |
468 | * | |
469 | * Characters generated by the ldisc (including echoes) need to | |
470 | * be buffered because the driver's write buffer can fill during | |
471 | * heavy program output. Echoing straight to the driver will | |
472 | * often fail under these conditions, causing lost characters and | |
473 | * resulting mismatches of ldisc state information. | |
474 | * | |
475 | * Since the ldisc state must represent the characters actually sent | |
476 | * to the driver at the time of the write, operations like certain | |
477 | * changes in column state are also saved in the buffer and executed | |
478 | * here. | |
479 | * | |
480 | * A circular fifo buffer is used so that the most recent characters | |
481 | * are prioritized. Also, when control characters are echoed with a | |
482 | * prefixed "^", the pair is treated atomically and thus not separated. | |
483 | * | |
484 | * Locking: output_lock to protect column state and space left, | |
485 | * echo_lock to protect the echo buffer | |
486 | */ | |
487 | ||
488 | static void process_echoes(struct tty_struct *tty) | |
489 | { | |
490 | int space, nr; | |
491 | unsigned char c; | |
492 | unsigned char *cp, *buf_end; | |
493 | ||
494 | if (!tty->echo_cnt) | |
495 | return; | |
496 | ||
497 | mutex_lock(&tty->output_lock); | |
498 | mutex_lock(&tty->echo_lock); | |
499 | ||
500 | space = tty_write_room(tty); | |
501 | ||
502 | buf_end = tty->echo_buf + N_TTY_BUF_SIZE; | |
503 | cp = tty->echo_buf + tty->echo_pos; | |
504 | nr = tty->echo_cnt; | |
505 | while (nr > 0) { | |
506 | c = *cp; | |
507 | if (c == ECHO_OP_START) { | |
508 | unsigned char op; | |
509 | unsigned char *opp; | |
510 | int no_space_left = 0; | |
511 | ||
512 | /* | |
513 | * If the buffer byte is the start of a multi-byte | |
514 | * operation, get the next byte, which is either the | |
515 | * op code or a control character value. | |
516 | */ | |
517 | opp = cp + 1; | |
518 | if (opp == buf_end) | |
519 | opp -= N_TTY_BUF_SIZE; | |
520 | op = *opp; | |
300a6204 | 521 | |
a88a69c9 JP |
522 | switch (op) { |
523 | unsigned int num_chars, num_bs; | |
524 | ||
525 | case ECHO_OP_ERASE_TAB: | |
526 | if (++opp == buf_end) | |
527 | opp -= N_TTY_BUF_SIZE; | |
528 | num_chars = *opp; | |
529 | ||
530 | /* | |
531 | * Determine how many columns to go back | |
532 | * in order to erase the tab. | |
533 | * This depends on the number of columns | |
534 | * used by other characters within the tab | |
535 | * area. If this (modulo 8) count is from | |
536 | * the start of input rather than from a | |
537 | * previous tab, we offset by canon column. | |
538 | * Otherwise, tab spacing is normal. | |
539 | */ | |
540 | if (!(num_chars & 0x80)) | |
541 | num_chars += tty->canon_column; | |
542 | num_bs = 8 - (num_chars & 7); | |
543 | ||
544 | if (num_bs > space) { | |
545 | no_space_left = 1; | |
546 | break; | |
547 | } | |
548 | space -= num_bs; | |
549 | while (num_bs--) { | |
550 | tty_put_char(tty, '\b'); | |
551 | if (tty->column > 0) | |
552 | tty->column--; | |
553 | } | |
554 | cp += 3; | |
555 | nr -= 3; | |
556 | break; | |
557 | ||
558 | case ECHO_OP_SET_CANON_COL: | |
559 | tty->canon_column = tty->column; | |
560 | cp += 2; | |
561 | nr -= 2; | |
562 | break; | |
563 | ||
564 | case ECHO_OP_MOVE_BACK_COL: | |
565 | if (tty->column > 0) | |
566 | tty->column--; | |
567 | cp += 2; | |
568 | nr -= 2; | |
569 | break; | |
570 | ||
571 | case ECHO_OP_START: | |
572 | /* This is an escaped echo op start code */ | |
573 | if (!space) { | |
574 | no_space_left = 1; | |
575 | break; | |
576 | } | |
577 | tty_put_char(tty, ECHO_OP_START); | |
578 | tty->column++; | |
579 | space--; | |
580 | cp += 2; | |
581 | nr -= 2; | |
582 | break; | |
583 | ||
584 | default: | |
a88a69c9 | 585 | /* |
62b26358 JP |
586 | * If the op is not a special byte code, |
587 | * it is a ctrl char tagged to be echoed | |
588 | * as "^X" (where X is the letter | |
589 | * representing the control char). | |
590 | * Note that we must ensure there is | |
591 | * enough space for the whole ctrl pair. | |
592 | * | |
a88a69c9 | 593 | */ |
62b26358 JP |
594 | if (space < 2) { |
595 | no_space_left = 1; | |
596 | break; | |
597 | } | |
598 | tty_put_char(tty, '^'); | |
599 | tty_put_char(tty, op ^ 0100); | |
600 | tty->column += 2; | |
601 | space -= 2; | |
a88a69c9 JP |
602 | cp += 2; |
603 | nr -= 2; | |
604 | } | |
605 | ||
606 | if (no_space_left) | |
607 | break; | |
608 | } else { | |
ee5aa7b8 JP |
609 | if (O_OPOST(tty) && |
610 | !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
611 | int retval = do_output_char(c, tty, space); | |
612 | if (retval < 0) | |
613 | break; | |
614 | space -= retval; | |
615 | } else { | |
616 | if (!space) | |
617 | break; | |
618 | tty_put_char(tty, c); | |
619 | space -= 1; | |
620 | } | |
a88a69c9 JP |
621 | cp += 1; |
622 | nr -= 1; | |
623 | } | |
624 | ||
625 | /* When end of circular buffer reached, wrap around */ | |
626 | if (cp >= buf_end) | |
627 | cp -= N_TTY_BUF_SIZE; | |
628 | } | |
629 | ||
630 | if (nr == 0) { | |
631 | tty->echo_pos = 0; | |
632 | tty->echo_cnt = 0; | |
633 | tty->echo_overrun = 0; | |
634 | } else { | |
635 | int num_processed = tty->echo_cnt - nr; | |
636 | tty->echo_pos += num_processed; | |
637 | tty->echo_pos &= N_TTY_BUF_SIZE - 1; | |
638 | tty->echo_cnt = nr; | |
639 | if (num_processed > 0) | |
640 | tty->echo_overrun = 0; | |
641 | } | |
642 | ||
643 | mutex_unlock(&tty->echo_lock); | |
644 | mutex_unlock(&tty->output_lock); | |
645 | ||
646 | if (tty->ops->flush_chars) | |
647 | tty->ops->flush_chars(tty); | |
648 | } | |
649 | ||
650 | /** | |
651 | * add_echo_byte - add a byte to the echo buffer | |
652 | * @c: unicode byte to echo | |
653 | * @tty: terminal device | |
654 | * | |
655 | * Add a character or operation byte to the echo buffer. | |
656 | * | |
657 | * Should be called under the echo lock to protect the echo buffer. | |
658 | */ | |
659 | ||
660 | static void add_echo_byte(unsigned char c, struct tty_struct *tty) | |
661 | { | |
662 | int new_byte_pos; | |
663 | ||
664 | if (tty->echo_cnt == N_TTY_BUF_SIZE) { | |
665 | /* Circular buffer is already at capacity */ | |
666 | new_byte_pos = tty->echo_pos; | |
667 | ||
668 | /* | |
669 | * Since the buffer start position needs to be advanced, | |
670 | * be sure to step by a whole operation byte group. | |
671 | */ | |
300a6204 | 672 | if (tty->echo_buf[tty->echo_pos] == ECHO_OP_START) { |
a88a69c9 JP |
673 | if (tty->echo_buf[(tty->echo_pos + 1) & |
674 | (N_TTY_BUF_SIZE - 1)] == | |
675 | ECHO_OP_ERASE_TAB) { | |
676 | tty->echo_pos += 3; | |
677 | tty->echo_cnt -= 2; | |
678 | } else { | |
679 | tty->echo_pos += 2; | |
680 | tty->echo_cnt -= 1; | |
681 | } | |
682 | } else { | |
683 | tty->echo_pos++; | |
684 | } | |
685 | tty->echo_pos &= N_TTY_BUF_SIZE - 1; | |
686 | ||
687 | tty->echo_overrun = 1; | |
688 | } else { | |
689 | new_byte_pos = tty->echo_pos + tty->echo_cnt; | |
690 | new_byte_pos &= N_TTY_BUF_SIZE - 1; | |
691 | tty->echo_cnt++; | |
692 | } | |
693 | ||
694 | tty->echo_buf[new_byte_pos] = c; | |
695 | } | |
696 | ||
697 | /** | |
698 | * echo_move_back_col - add operation to move back a column | |
699 | * @tty: terminal device | |
700 | * | |
701 | * Add an operation to the echo buffer to move back one column. | |
702 | * | |
703 | * Locking: echo_lock to protect the echo buffer | |
704 | */ | |
705 | ||
706 | static void echo_move_back_col(struct tty_struct *tty) | |
707 | { | |
708 | mutex_lock(&tty->echo_lock); | |
709 | ||
710 | add_echo_byte(ECHO_OP_START, tty); | |
711 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty); | |
712 | ||
713 | mutex_unlock(&tty->echo_lock); | |
714 | } | |
715 | ||
716 | /** | |
717 | * echo_set_canon_col - add operation to set the canon column | |
718 | * @tty: terminal device | |
719 | * | |
720 | * Add an operation to the echo buffer to set the canon column | |
721 | * to the current column. | |
722 | * | |
723 | * Locking: echo_lock to protect the echo buffer | |
724 | */ | |
725 | ||
726 | static void echo_set_canon_col(struct tty_struct *tty) | |
727 | { | |
728 | mutex_lock(&tty->echo_lock); | |
729 | ||
730 | add_echo_byte(ECHO_OP_START, tty); | |
731 | add_echo_byte(ECHO_OP_SET_CANON_COL, tty); | |
732 | ||
733 | mutex_unlock(&tty->echo_lock); | |
734 | } | |
735 | ||
736 | /** | |
737 | * echo_erase_tab - add operation to erase a tab | |
738 | * @num_chars: number of character columns already used | |
739 | * @after_tab: true if num_chars starts after a previous tab | |
740 | * @tty: terminal device | |
741 | * | |
742 | * Add an operation to the echo buffer to erase a tab. | |
743 | * | |
744 | * Called by the eraser function, which knows how many character | |
745 | * columns have been used since either a previous tab or the start | |
746 | * of input. This information will be used later, along with | |
747 | * canon column (if applicable), to go back the correct number | |
748 | * of columns. | |
749 | * | |
750 | * Locking: echo_lock to protect the echo buffer | |
751 | */ | |
752 | ||
753 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
754 | struct tty_struct *tty) | |
755 | { | |
756 | mutex_lock(&tty->echo_lock); | |
757 | ||
758 | add_echo_byte(ECHO_OP_START, tty); | |
759 | add_echo_byte(ECHO_OP_ERASE_TAB, tty); | |
760 | ||
761 | /* We only need to know this modulo 8 (tab spacing) */ | |
762 | num_chars &= 7; | |
763 | ||
764 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
765 | if (after_tab) | |
766 | num_chars |= 0x80; | |
300a6204 | 767 | |
a88a69c9 JP |
768 | add_echo_byte(num_chars, tty); |
769 | ||
770 | mutex_unlock(&tty->echo_lock); | |
771 | } | |
772 | ||
773 | /** | |
774 | * echo_char_raw - echo a character raw | |
775 | * @c: unicode byte to echo | |
776 | * @tty: terminal device | |
777 | * | |
778 | * Echo user input back onto the screen. This must be called only when | |
779 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
780 | * | |
781 | * This variant does not treat control characters specially. | |
782 | * | |
783 | * Locking: echo_lock to protect the echo buffer | |
784 | */ | |
785 | ||
786 | static void echo_char_raw(unsigned char c, struct tty_struct *tty) | |
787 | { | |
788 | mutex_lock(&tty->echo_lock); | |
789 | ||
790 | if (c == ECHO_OP_START) { | |
791 | add_echo_byte(ECHO_OP_START, tty); | |
792 | add_echo_byte(ECHO_OP_START, tty); | |
793 | } else { | |
794 | add_echo_byte(c, tty); | |
795 | } | |
796 | ||
797 | mutex_unlock(&tty->echo_lock); | |
798 | } | |
1da177e4 | 799 | |
1da177e4 | 800 | /** |
a88a69c9 | 801 | * echo_char - echo a character |
1da177e4 LT |
802 | * @c: unicode byte to echo |
803 | * @tty: terminal device | |
804 | * | |
4edf1827 | 805 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 806 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 807 | * |
62b26358 JP |
808 | * This variant tags control characters to be echoed as "^X" |
809 | * (where X is the letter representing the control char). | |
a88a69c9 JP |
810 | * |
811 | * Locking: echo_lock to protect the echo buffer | |
1da177e4 LT |
812 | */ |
813 | ||
814 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
815 | { | |
a88a69c9 JP |
816 | mutex_lock(&tty->echo_lock); |
817 | ||
818 | if (c == ECHO_OP_START) { | |
819 | add_echo_byte(ECHO_OP_START, tty); | |
820 | add_echo_byte(ECHO_OP_START, tty); | |
821 | } else { | |
62b26358 | 822 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
a88a69c9 JP |
823 | add_echo_byte(ECHO_OP_START, tty); |
824 | add_echo_byte(c, tty); | |
825 | } | |
826 | ||
827 | mutex_unlock(&tty->echo_lock); | |
1da177e4 LT |
828 | } |
829 | ||
17b82060 | 830 | /** |
a88a69c9 | 831 | * finish_erasing - complete erase |
17b82060 | 832 | * @tty: tty doing the erase |
17b82060 | 833 | */ |
a88a69c9 | 834 | |
1da177e4 LT |
835 | static inline void finish_erasing(struct tty_struct *tty) |
836 | { | |
837 | if (tty->erasing) { | |
a88a69c9 | 838 | echo_char_raw('/', tty); |
1da177e4 LT |
839 | tty->erasing = 0; |
840 | } | |
841 | } | |
842 | ||
843 | /** | |
844 | * eraser - handle erase function | |
845 | * @c: character input | |
846 | * @tty: terminal device | |
847 | * | |
3a4fa0a2 | 848 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
849 | * present in the stream from the driver layer. Handles the complexities |
850 | * of UTF-8 multibyte symbols. | |
17b82060 | 851 | * |
a88a69c9 | 852 | * Locking: read_lock for tty buffers |
1da177e4 | 853 | */ |
4edf1827 | 854 | |
1da177e4 LT |
855 | static void eraser(unsigned char c, struct tty_struct *tty) |
856 | { | |
857 | enum { ERASE, WERASE, KILL } kill_type; | |
858 | int head, seen_alnums, cnt; | |
859 | unsigned long flags; | |
860 | ||
17b82060 | 861 | /* FIXME: locking needed ? */ |
1da177e4 | 862 | if (tty->read_head == tty->canon_head) { |
7e94b1d9 | 863 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
864 | return; |
865 | } | |
866 | if (c == ERASE_CHAR(tty)) | |
867 | kill_type = ERASE; | |
868 | else if (c == WERASE_CHAR(tty)) | |
869 | kill_type = WERASE; | |
870 | else { | |
871 | if (!L_ECHO(tty)) { | |
872 | spin_lock_irqsave(&tty->read_lock, flags); | |
873 | tty->read_cnt -= ((tty->read_head - tty->canon_head) & | |
874 | (N_TTY_BUF_SIZE - 1)); | |
875 | tty->read_head = tty->canon_head; | |
876 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
877 | return; | |
878 | } | |
879 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
880 | spin_lock_irqsave(&tty->read_lock, flags); | |
881 | tty->read_cnt -= ((tty->read_head - tty->canon_head) & | |
882 | (N_TTY_BUF_SIZE - 1)); | |
883 | tty->read_head = tty->canon_head; | |
884 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
885 | finish_erasing(tty); | |
886 | echo_char(KILL_CHAR(tty), tty); | |
887 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
888 | if (L_ECHOK(tty)) | |
a88a69c9 | 889 | echo_char_raw('\n', tty); |
1da177e4 LT |
890 | return; |
891 | } | |
892 | kill_type = KILL; | |
893 | } | |
894 | ||
895 | seen_alnums = 0; | |
17b82060 | 896 | /* FIXME: Locking ?? */ |
1da177e4 LT |
897 | while (tty->read_head != tty->canon_head) { |
898 | head = tty->read_head; | |
899 | ||
900 | /* erase a single possibly multibyte character */ | |
901 | do { | |
902 | head = (head - 1) & (N_TTY_BUF_SIZE-1); | |
903 | c = tty->read_buf[head]; | |
904 | } while (is_continuation(c, tty) && head != tty->canon_head); | |
905 | ||
906 | /* do not partially erase */ | |
907 | if (is_continuation(c, tty)) | |
908 | break; | |
909 | ||
910 | if (kill_type == WERASE) { | |
911 | /* Equivalent to BSD's ALTWERASE. */ | |
912 | if (isalnum(c) || c == '_') | |
913 | seen_alnums++; | |
914 | else if (seen_alnums) | |
915 | break; | |
916 | } | |
917 | cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1); | |
918 | spin_lock_irqsave(&tty->read_lock, flags); | |
919 | tty->read_head = head; | |
920 | tty->read_cnt -= cnt; | |
921 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
922 | if (L_ECHO(tty)) { | |
923 | if (L_ECHOPRT(tty)) { | |
924 | if (!tty->erasing) { | |
a88a69c9 | 925 | echo_char_raw('\\', tty); |
1da177e4 LT |
926 | tty->erasing = 1; |
927 | } | |
928 | /* if cnt > 1, output a multi-byte character */ | |
929 | echo_char(c, tty); | |
930 | while (--cnt > 0) { | |
931 | head = (head+1) & (N_TTY_BUF_SIZE-1); | |
a88a69c9 JP |
932 | echo_char_raw(tty->read_buf[head], tty); |
933 | echo_move_back_col(tty); | |
1da177e4 LT |
934 | } |
935 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
936 | echo_char(ERASE_CHAR(tty), tty); | |
937 | } else if (c == '\t') { | |
a88a69c9 JP |
938 | unsigned int num_chars = 0; |
939 | int after_tab = 0; | |
940 | unsigned long tail = tty->read_head; | |
941 | ||
942 | /* | |
943 | * Count the columns used for characters | |
944 | * since the start of input or after a | |
945 | * previous tab. | |
946 | * This info is used to go back the correct | |
947 | * number of columns. | |
948 | */ | |
949 | while (tail != tty->canon_head) { | |
950 | tail = (tail-1) & (N_TTY_BUF_SIZE-1); | |
1da177e4 | 951 | c = tty->read_buf[tail]; |
a88a69c9 JP |
952 | if (c == '\t') { |
953 | after_tab = 1; | |
954 | break; | |
300a6204 | 955 | } else if (iscntrl(c)) { |
1da177e4 | 956 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
957 | num_chars += 2; |
958 | } else if (!is_continuation(c, tty)) { | |
959 | num_chars++; | |
960 | } | |
1da177e4 | 961 | } |
a88a69c9 | 962 | echo_erase_tab(num_chars, after_tab, tty); |
1da177e4 LT |
963 | } else { |
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 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
a88a69c9 JP |
970 | echo_char_raw('\b', tty); |
971 | echo_char_raw(' ', tty); | |
972 | echo_char_raw('\b', tty); | |
1da177e4 LT |
973 | } |
974 | } | |
975 | } | |
976 | if (kill_type == ERASE) | |
977 | break; | |
978 | } | |
a88a69c9 | 979 | if (tty->read_head == tty->canon_head && L_ECHO(tty)) |
1da177e4 LT |
980 | finish_erasing(tty); |
981 | } | |
982 | ||
983 | /** | |
984 | * isig - handle the ISIG optio | |
985 | * @sig: signal | |
986 | * @tty: terminal | |
987 | * @flush: force flush | |
988 | * | |
989 | * Called when a signal is being sent due to terminal input. This | |
990 | * may caus terminal flushing to take place according to the termios | |
991 | * settings and character used. Called from the driver receive_buf | |
992 | * path so serialized. | |
17b82060 AC |
993 | * |
994 | * Locking: ctrl_lock, read_lock (both via flush buffer) | |
1da177e4 | 995 | */ |
4edf1827 | 996 | |
1da177e4 LT |
997 | static inline void isig(int sig, struct tty_struct *tty, int flush) |
998 | { | |
ab521dc0 EB |
999 | if (tty->pgrp) |
1000 | kill_pgrp(tty->pgrp, sig, 1); | |
1da177e4 LT |
1001 | if (flush || !L_NOFLSH(tty)) { |
1002 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1003 | tty_driver_flush_buffer(tty); |
1da177e4 LT |
1004 | } |
1005 | } | |
1006 | ||
1007 | /** | |
1008 | * n_tty_receive_break - handle break | |
1009 | * @tty: terminal | |
1010 | * | |
1011 | * An RS232 break event has been hit in the incoming bitstream. This | |
1012 | * can cause a variety of events depending upon the termios settings. | |
1013 | * | |
1014 | * Called from the receive_buf path so single threaded. | |
1015 | */ | |
4edf1827 | 1016 | |
1da177e4 LT |
1017 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1018 | { | |
1019 | if (I_IGNBRK(tty)) | |
1020 | return; | |
1021 | if (I_BRKINT(tty)) { | |
1022 | isig(SIGINT, tty, 1); | |
1023 | return; | |
1024 | } | |
1025 | if (I_PARMRK(tty)) { | |
1026 | put_tty_queue('\377', tty); | |
1027 | put_tty_queue('\0', tty); | |
1028 | } | |
1029 | put_tty_queue('\0', tty); | |
1030 | wake_up_interruptible(&tty->read_wait); | |
1031 | } | |
1032 | ||
1033 | /** | |
1034 | * n_tty_receive_overrun - handle overrun reporting | |
1035 | * @tty: terminal | |
1036 | * | |
1037 | * Data arrived faster than we could process it. While the tty | |
1038 | * driver has flagged this the bits that were missed are gone | |
1039 | * forever. | |
1040 | * | |
1041 | * Called from the receive_buf path so single threaded. Does not | |
1042 | * need locking as num_overrun and overrun_time are function | |
1043 | * private. | |
1044 | */ | |
4edf1827 | 1045 | |
1da177e4 LT |
1046 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1047 | { | |
1048 | char buf[64]; | |
1049 | ||
1050 | tty->num_overrun++; | |
1051 | if (time_before(tty->overrun_time, jiffies - HZ) || | |
1052 | time_after(tty->overrun_time, jiffies)) { | |
1053 | printk(KERN_WARNING "%s: %d input overrun(s)\n", | |
1054 | tty_name(tty, buf), | |
1055 | tty->num_overrun); | |
1056 | tty->overrun_time = jiffies; | |
1057 | tty->num_overrun = 0; | |
1058 | } | |
1059 | } | |
1060 | ||
1061 | /** | |
1062 | * n_tty_receive_parity_error - error notifier | |
1063 | * @tty: terminal device | |
1064 | * @c: character | |
1065 | * | |
1066 | * Process a parity error and queue the right data to indicate | |
3a4fa0a2 | 1067 | * the error case if necessary. Locking as per n_tty_receive_buf. |
1da177e4 LT |
1068 | */ |
1069 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1070 | unsigned char c) | |
1071 | { | |
4edf1827 | 1072 | if (I_IGNPAR(tty)) |
1da177e4 | 1073 | return; |
1da177e4 LT |
1074 | if (I_PARMRK(tty)) { |
1075 | put_tty_queue('\377', tty); | |
1076 | put_tty_queue('\0', tty); | |
1077 | put_tty_queue(c, tty); | |
1078 | } else if (I_INPCK(tty)) | |
1079 | put_tty_queue('\0', tty); | |
1080 | else | |
1081 | put_tty_queue(c, tty); | |
1082 | wake_up_interruptible(&tty->read_wait); | |
1083 | } | |
1084 | ||
1085 | /** | |
1086 | * n_tty_receive_char - perform processing | |
1087 | * @tty: terminal device | |
1088 | * @c: character | |
1089 | * | |
1090 | * Process an individual character of input received from the driver. | |
4edf1827 | 1091 | * This is serialized with respect to itself by the rules for the |
1da177e4 LT |
1092 | * driver above. |
1093 | */ | |
1094 | ||
1095 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1096 | { | |
1097 | unsigned long flags; | |
acc71bba | 1098 | int parmrk; |
1da177e4 LT |
1099 | |
1100 | if (tty->raw) { | |
1101 | put_tty_queue(c, tty); | |
1102 | return; | |
1103 | } | |
4edf1827 | 1104 | |
1da177e4 LT |
1105 | if (I_ISTRIP(tty)) |
1106 | c &= 0x7f; | |
1107 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1108 | c = tolower(c); |
1da177e4 | 1109 | |
26df6d13 | 1110 | if (L_EXTPROC(tty)) { |
1111 | put_tty_queue(c, tty); | |
1112 | return; | |
1113 | } | |
1114 | ||
54d2a37e | 1115 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1116 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1117 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1118 | start_tty(tty); |
a88a69c9 JP |
1119 | process_echoes(tty); |
1120 | } | |
54d2a37e | 1121 | |
1da177e4 LT |
1122 | if (tty->closing) { |
1123 | if (I_IXON(tty)) { | |
a88a69c9 | 1124 | if (c == START_CHAR(tty)) { |
1da177e4 | 1125 | start_tty(tty); |
a88a69c9 | 1126 | process_echoes(tty); |
300a6204 | 1127 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1128 | stop_tty(tty); |
1129 | } | |
1130 | return; | |
1131 | } | |
1132 | ||
1133 | /* | |
1134 | * If the previous character was LNEXT, or we know that this | |
1135 | * character is not one of the characters that we'll have to | |
1136 | * handle specially, do shortcut processing to speed things | |
1137 | * up. | |
1138 | */ | |
1139 | if (!test_bit(c, tty->process_char_map) || tty->lnext) { | |
1da177e4 | 1140 | tty->lnext = 0; |
acc71bba JP |
1141 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
1142 | if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { | |
1143 | /* beep if no space */ | |
7e94b1d9 JP |
1144 | if (L_ECHO(tty)) |
1145 | process_output('\a', tty); | |
acc71bba JP |
1146 | return; |
1147 | } | |
1148 | if (L_ECHO(tty)) { | |
1149 | finish_erasing(tty); | |
1da177e4 LT |
1150 | /* Record the column of first canon char. */ |
1151 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1152 | echo_set_canon_col(tty); |
1da177e4 | 1153 | echo_char(c, tty); |
a88a69c9 | 1154 | process_echoes(tty); |
1da177e4 | 1155 | } |
acc71bba | 1156 | if (parmrk) |
1da177e4 LT |
1157 | put_tty_queue(c, tty); |
1158 | put_tty_queue(c, tty); | |
1159 | return; | |
1160 | } | |
4edf1827 | 1161 | |
1da177e4 LT |
1162 | if (I_IXON(tty)) { |
1163 | if (c == START_CHAR(tty)) { | |
1164 | start_tty(tty); | |
a88a69c9 | 1165 | process_echoes(tty); |
1da177e4 LT |
1166 | return; |
1167 | } | |
1168 | if (c == STOP_CHAR(tty)) { | |
1169 | stop_tty(tty); | |
1170 | return; | |
1171 | } | |
1172 | } | |
575537b3 | 1173 | |
1da177e4 LT |
1174 | if (L_ISIG(tty)) { |
1175 | int signal; | |
1176 | signal = SIGINT; | |
1177 | if (c == INTR_CHAR(tty)) | |
1178 | goto send_signal; | |
1179 | signal = SIGQUIT; | |
1180 | if (c == QUIT_CHAR(tty)) | |
1181 | goto send_signal; | |
1182 | signal = SIGTSTP; | |
1183 | if (c == SUSP_CHAR(tty)) { | |
1184 | send_signal: | |
ec5b1157 | 1185 | /* |
ec5b1157 JP |
1186 | * Note that we do not use isig() here because we want |
1187 | * the order to be: | |
1188 | * 1) flush, 2) echo, 3) signal | |
1189 | */ | |
1190 | if (!L_NOFLSH(tty)) { | |
1191 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1192 | tty_driver_flush_buffer(tty); |
ec5b1157 | 1193 | } |
a88a69c9 JP |
1194 | if (I_IXON(tty)) |
1195 | start_tty(tty); | |
1196 | if (L_ECHO(tty)) { | |
ec5b1157 | 1197 | echo_char(c, tty); |
a88a69c9 JP |
1198 | process_echoes(tty); |
1199 | } | |
ec5b1157 JP |
1200 | if (tty->pgrp) |
1201 | kill_pgrp(tty->pgrp, signal, 1); | |
1da177e4 LT |
1202 | return; |
1203 | } | |
1204 | } | |
575537b3 JP |
1205 | |
1206 | if (c == '\r') { | |
1207 | if (I_IGNCR(tty)) | |
1208 | return; | |
1209 | if (I_ICRNL(tty)) | |
1210 | c = '\n'; | |
1211 | } else if (c == '\n' && I_INLCR(tty)) | |
1212 | c = '\r'; | |
1213 | ||
1da177e4 LT |
1214 | if (tty->icanon) { |
1215 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || | |
1216 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1217 | eraser(c, tty); | |
a88a69c9 | 1218 | process_echoes(tty); |
1da177e4 LT |
1219 | return; |
1220 | } | |
1221 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
1222 | tty->lnext = 1; | |
1223 | if (L_ECHO(tty)) { | |
1224 | finish_erasing(tty); | |
1225 | if (L_ECHOCTL(tty)) { | |
a88a69c9 JP |
1226 | echo_char_raw('^', tty); |
1227 | echo_char_raw('\b', tty); | |
1228 | process_echoes(tty); | |
1da177e4 LT |
1229 | } |
1230 | } | |
1231 | return; | |
1232 | } | |
1233 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1234 | L_IEXTEN(tty)) { | |
1235 | unsigned long tail = tty->canon_head; | |
1236 | ||
1237 | finish_erasing(tty); | |
1238 | echo_char(c, tty); | |
a88a69c9 | 1239 | echo_char_raw('\n', tty); |
1da177e4 LT |
1240 | while (tail != tty->read_head) { |
1241 | echo_char(tty->read_buf[tail], tty); | |
1242 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
1243 | } | |
a88a69c9 | 1244 | process_echoes(tty); |
1da177e4 LT |
1245 | return; |
1246 | } | |
1247 | if (c == '\n') { | |
acc71bba | 1248 | if (tty->read_cnt >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1249 | if (L_ECHO(tty)) |
1250 | process_output('\a', tty); | |
acc71bba JP |
1251 | return; |
1252 | } | |
1253 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
a88a69c9 JP |
1254 | echo_char_raw('\n', tty); |
1255 | process_echoes(tty); | |
1da177e4 LT |
1256 | } |
1257 | goto handle_newline; | |
1258 | } | |
1259 | if (c == EOF_CHAR(tty)) { | |
acc71bba JP |
1260 | if (tty->read_cnt >= N_TTY_BUF_SIZE) |
1261 | return; | |
4edf1827 AC |
1262 | if (tty->canon_head != tty->read_head) |
1263 | set_bit(TTY_PUSH, &tty->flags); | |
1da177e4 LT |
1264 | c = __DISABLED_CHAR; |
1265 | goto handle_newline; | |
1266 | } | |
1267 | if ((c == EOL_CHAR(tty)) || | |
1268 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1269 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1270 | ? 1 : 0; | |
1271 | if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) { | |
7e94b1d9 JP |
1272 | if (L_ECHO(tty)) |
1273 | process_output('\a', tty); | |
acc71bba JP |
1274 | return; |
1275 | } | |
1da177e4 LT |
1276 | /* |
1277 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1278 | */ | |
1279 | if (L_ECHO(tty)) { | |
1da177e4 LT |
1280 | /* Record the column of first canon char. */ |
1281 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1282 | echo_set_canon_col(tty); |
1da177e4 | 1283 | echo_char(c, tty); |
a88a69c9 | 1284 | process_echoes(tty); |
1da177e4 LT |
1285 | } |
1286 | /* | |
1287 | * XXX does PARMRK doubling happen for | |
1288 | * EOL_CHAR and EOL2_CHAR? | |
1289 | */ | |
acc71bba | 1290 | if (parmrk) |
1da177e4 LT |
1291 | put_tty_queue(c, tty); |
1292 | ||
4edf1827 | 1293 | handle_newline: |
1da177e4 LT |
1294 | spin_lock_irqsave(&tty->read_lock, flags); |
1295 | set_bit(tty->read_head, tty->read_flags); | |
1296 | put_tty_queue_nolock(c, tty); | |
1297 | tty->canon_head = tty->read_head; | |
1298 | tty->canon_data++; | |
1299 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1300 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); | |
1301 | if (waitqueue_active(&tty->read_wait)) | |
1302 | wake_up_interruptible(&tty->read_wait); | |
1303 | return; | |
1304 | } | |
1305 | } | |
4edf1827 | 1306 | |
acc71bba JP |
1307 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
1308 | if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { | |
1309 | /* beep if no space */ | |
7e94b1d9 JP |
1310 | if (L_ECHO(tty)) |
1311 | process_output('\a', tty); | |
acc71bba JP |
1312 | return; |
1313 | } | |
1314 | if (L_ECHO(tty)) { | |
1315 | finish_erasing(tty); | |
1da177e4 | 1316 | if (c == '\n') |
a88a69c9 | 1317 | echo_char_raw('\n', tty); |
1da177e4 LT |
1318 | else { |
1319 | /* Record the column of first canon char. */ | |
1320 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1321 | echo_set_canon_col(tty); |
1da177e4 LT |
1322 | echo_char(c, tty); |
1323 | } | |
a88a69c9 | 1324 | process_echoes(tty); |
1da177e4 LT |
1325 | } |
1326 | ||
acc71bba | 1327 | if (parmrk) |
1da177e4 LT |
1328 | put_tty_queue(c, tty); |
1329 | ||
1330 | put_tty_queue(c, tty); | |
4edf1827 | 1331 | } |
1da177e4 | 1332 | |
1da177e4 LT |
1333 | |
1334 | /** | |
1335 | * n_tty_write_wakeup - asynchronous I/O notifier | |
1336 | * @tty: tty device | |
1337 | * | |
1338 | * Required for the ptys, serial driver etc. since processes | |
1339 | * that attach themselves to the master and rely on ASYNC | |
1340 | * IO must be woken up | |
1341 | */ | |
1342 | ||
1343 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
1344 | { | |
ff8cb0fd | 1345 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) |
1da177e4 | 1346 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); |
1da177e4 LT |
1347 | } |
1348 | ||
1349 | /** | |
1350 | * n_tty_receive_buf - data receive | |
1351 | * @tty: terminal device | |
1352 | * @cp: buffer | |
1353 | * @fp: flag buffer | |
1354 | * @count: characters | |
1355 | * | |
1356 | * Called by the terminal driver when a block of characters has | |
1357 | * been received. This function must be called from soft contexts | |
1358 | * not from interrupt context. The driver is responsible for making | |
1359 | * calls one at a time and in order (or using flush_to_ldisc) | |
1360 | */ | |
4edf1827 | 1361 | |
55db4c64 LT |
1362 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1363 | char *fp, int count) | |
1da177e4 LT |
1364 | { |
1365 | const unsigned char *p; | |
1366 | char *f, flags = TTY_NORMAL; | |
1367 | int i; | |
1368 | char buf[64]; | |
1369 | unsigned long cpuflags; | |
1370 | ||
1371 | if (!tty->read_buf) | |
55db4c64 | 1372 | return; |
1da177e4 LT |
1373 | |
1374 | if (tty->real_raw) { | |
1375 | spin_lock_irqsave(&tty->read_lock, cpuflags); | |
1376 | i = min(N_TTY_BUF_SIZE - tty->read_cnt, | |
1377 | N_TTY_BUF_SIZE - tty->read_head); | |
1378 | i = min(count, i); | |
1379 | memcpy(tty->read_buf + tty->read_head, cp, i); | |
1380 | tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1381 | tty->read_cnt += i; | |
1382 | cp += i; | |
1383 | count -= i; | |
1384 | ||
1385 | i = min(N_TTY_BUF_SIZE - tty->read_cnt, | |
1386 | N_TTY_BUF_SIZE - tty->read_head); | |
1387 | i = min(count, i); | |
1388 | memcpy(tty->read_buf + tty->read_head, cp, i); | |
1389 | tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1390 | tty->read_cnt += i; | |
1391 | spin_unlock_irqrestore(&tty->read_lock, cpuflags); | |
1392 | } else { | |
4edf1827 | 1393 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1394 | if (f) |
1395 | flags = *f++; | |
1396 | switch (flags) { | |
1397 | case TTY_NORMAL: | |
1398 | n_tty_receive_char(tty, *p); | |
1399 | break; | |
1400 | case TTY_BREAK: | |
1401 | n_tty_receive_break(tty); | |
1402 | break; | |
1403 | case TTY_PARITY: | |
1404 | case TTY_FRAME: | |
1405 | n_tty_receive_parity_error(tty, *p); | |
1406 | break; | |
1407 | case TTY_OVERRUN: | |
1408 | n_tty_receive_overrun(tty); | |
1409 | break; | |
1410 | default: | |
4edf1827 | 1411 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1412 | tty_name(tty, buf), flags); |
1413 | break; | |
1414 | } | |
1415 | } | |
f34d7a5b AC |
1416 | if (tty->ops->flush_chars) |
1417 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1418 | } |
1419 | ||
55db4c64 LT |
1420 | n_tty_set_room(tty); |
1421 | ||
26df6d13 | 1422 | if ((!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) || |
1423 | L_EXTPROC(tty)) { | |
1da177e4 LT |
1424 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1425 | if (waitqueue_active(&tty->read_wait)) | |
1426 | wake_up_interruptible(&tty->read_wait); | |
1427 | } | |
1428 | ||
1429 | /* | |
1430 | * Check the remaining room for the input canonicalization | |
1431 | * mode. We don't want to throttle the driver if we're in | |
1432 | * canonical mode and don't have a newline yet! | |
1433 | */ | |
55db4c64 | 1434 | if (tty->receive_room < TTY_THRESHOLD_THROTTLE) |
39c2e60f | 1435 | tty_throttle(tty); |
1da177e4 LT |
1436 | } |
1437 | ||
1438 | int is_ignored(int sig) | |
1439 | { | |
1440 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1441 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1442 | } |
1443 | ||
1444 | /** | |
1445 | * n_tty_set_termios - termios data changed | |
1446 | * @tty: terminal | |
1447 | * @old: previous data | |
1448 | * | |
1449 | * Called by the tty layer when the user changes termios flags so | |
1450 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1451 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1452 | * guaranteed that this function will not be re-entered or in progress |
1453 | * when the ldisc is closed. | |
17b82060 AC |
1454 | * |
1455 | * Locking: Caller holds tty->termios_mutex | |
1da177e4 | 1456 | */ |
4edf1827 AC |
1457 | |
1458 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1459 | { |
47afa7a5 AC |
1460 | int canon_change = 1; |
1461 | BUG_ON(!tty); | |
1462 | ||
1463 | if (old) | |
1464 | canon_change = (old->c_lflag ^ tty->termios->c_lflag) & ICANON; | |
1465 | if (canon_change) { | |
1466 | memset(&tty->read_flags, 0, sizeof tty->read_flags); | |
1467 | tty->canon_head = tty->read_tail; | |
1468 | tty->canon_data = 0; | |
1469 | tty->erasing = 0; | |
1470 | } | |
1471 | ||
1472 | if (canon_change && !L_ICANON(tty) && tty->read_cnt) | |
1473 | wake_up_interruptible(&tty->read_wait); | |
4edf1827 | 1474 | |
1da177e4 LT |
1475 | tty->icanon = (L_ICANON(tty) != 0); |
1476 | if (test_bit(TTY_HW_COOK_IN, &tty->flags)) { | |
1477 | tty->raw = 1; | |
1478 | tty->real_raw = 1; | |
55db4c64 | 1479 | n_tty_set_room(tty); |
1da177e4 LT |
1480 | return; |
1481 | } | |
1482 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || | |
1483 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1484 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1485 | I_PARMRK(tty)) { | |
1486 | memset(tty->process_char_map, 0, 256/8); | |
1487 | ||
1488 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1489 | set_bit('\r', tty->process_char_map); | |
1490 | if (I_INLCR(tty)) | |
1491 | set_bit('\n', tty->process_char_map); | |
1492 | ||
1493 | if (L_ICANON(tty)) { | |
1494 | set_bit(ERASE_CHAR(tty), tty->process_char_map); | |
1495 | set_bit(KILL_CHAR(tty), tty->process_char_map); | |
1496 | set_bit(EOF_CHAR(tty), tty->process_char_map); | |
1497 | set_bit('\n', tty->process_char_map); | |
1498 | set_bit(EOL_CHAR(tty), tty->process_char_map); | |
1499 | if (L_IEXTEN(tty)) { | |
1500 | set_bit(WERASE_CHAR(tty), | |
1501 | tty->process_char_map); | |
1502 | set_bit(LNEXT_CHAR(tty), | |
1503 | tty->process_char_map); | |
1504 | set_bit(EOL2_CHAR(tty), | |
1505 | tty->process_char_map); | |
1506 | if (L_ECHO(tty)) | |
1507 | set_bit(REPRINT_CHAR(tty), | |
1508 | tty->process_char_map); | |
1509 | } | |
1510 | } | |
1511 | if (I_IXON(tty)) { | |
1512 | set_bit(START_CHAR(tty), tty->process_char_map); | |
1513 | set_bit(STOP_CHAR(tty), tty->process_char_map); | |
1514 | } | |
1515 | if (L_ISIG(tty)) { | |
1516 | set_bit(INTR_CHAR(tty), tty->process_char_map); | |
1517 | set_bit(QUIT_CHAR(tty), tty->process_char_map); | |
1518 | set_bit(SUSP_CHAR(tty), tty->process_char_map); | |
1519 | } | |
1520 | clear_bit(__DISABLED_CHAR, tty->process_char_map); | |
1521 | tty->raw = 0; | |
1522 | tty->real_raw = 0; | |
1523 | } else { | |
1524 | tty->raw = 1; | |
1525 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && | |
1526 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1527 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
1528 | tty->real_raw = 1; | |
1529 | else | |
1530 | tty->real_raw = 0; | |
1531 | } | |
55db4c64 | 1532 | n_tty_set_room(tty); |
f34d7a5b AC |
1533 | /* The termios change make the tty ready for I/O */ |
1534 | wake_up_interruptible(&tty->write_wait); | |
1535 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1536 | } |
1537 | ||
1538 | /** | |
1539 | * n_tty_close - close the ldisc for this tty | |
1540 | * @tty: device | |
1541 | * | |
4edf1827 AC |
1542 | * Called from the terminal layer when this line discipline is |
1543 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1544 | * discipline change. The function will not be called while other |
1545 | * ldisc methods are in progress. | |
1546 | */ | |
4edf1827 | 1547 | |
1da177e4 LT |
1548 | static void n_tty_close(struct tty_struct *tty) |
1549 | { | |
1550 | n_tty_flush_buffer(tty); | |
1551 | if (tty->read_buf) { | |
0b4068a1 | 1552 | kfree(tty->read_buf); |
1da177e4 LT |
1553 | tty->read_buf = NULL; |
1554 | } | |
a88a69c9 | 1555 | if (tty->echo_buf) { |
0b4068a1 | 1556 | kfree(tty->echo_buf); |
a88a69c9 JP |
1557 | tty->echo_buf = NULL; |
1558 | } | |
1da177e4 LT |
1559 | } |
1560 | ||
1561 | /** | |
1562 | * n_tty_open - open an ldisc | |
1563 | * @tty: terminal to open | |
1564 | * | |
4edf1827 | 1565 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1566 | * terminal device. Can sleep. Called serialized so that no |
1567 | * other events will occur in parallel. No further open will occur | |
1568 | * until a close. | |
1569 | */ | |
1570 | ||
1571 | static int n_tty_open(struct tty_struct *tty) | |
1572 | { | |
1573 | if (!tty) | |
1574 | return -EINVAL; | |
1575 | ||
a88a69c9 | 1576 | /* These are ugly. Currently a malloc failure here can panic */ |
1da177e4 | 1577 | if (!tty->read_buf) { |
0b4068a1 | 1578 | tty->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1da177e4 LT |
1579 | if (!tty->read_buf) |
1580 | return -ENOMEM; | |
1581 | } | |
a88a69c9 | 1582 | if (!tty->echo_buf) { |
0b4068a1 AC |
1583 | tty->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1584 | ||
a88a69c9 JP |
1585 | if (!tty->echo_buf) |
1586 | return -ENOMEM; | |
1587 | } | |
1da177e4 | 1588 | reset_buffer_flags(tty); |
7b292b4b | 1589 | tty_unthrottle(tty); |
1da177e4 LT |
1590 | tty->column = 0; |
1591 | n_tty_set_termios(tty, NULL); | |
1592 | tty->minimum_to_wake = 1; | |
1593 | tty->closing = 0; | |
1594 | return 0; | |
1595 | } | |
1596 | ||
1597 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1598 | { | |
e043e42b | 1599 | tty_flush_to_ldisc(tty); |
26df6d13 | 1600 | if (tty->icanon && !L_EXTPROC(tty)) { |
1da177e4 LT |
1601 | if (tty->canon_data) |
1602 | return 1; | |
1603 | } else if (tty->read_cnt >= (amt ? amt : 1)) | |
1604 | return 1; | |
1605 | ||
1606 | return 0; | |
1607 | } | |
1608 | ||
1609 | /** | |
bbd20759 | 1610 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1611 | * @tty: terminal device |
1612 | * @b: user data | |
1613 | * @nr: size of data | |
1614 | * | |
11a96d18 | 1615 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1616 | * ICANON is off; it copies characters straight from the tty queue to |
1617 | * user space directly. It can be profitably called twice; once to | |
1618 | * drain the space from the tail pointer to the (physical) end of the | |
1619 | * buffer, and once to drain the space from the (physical) beginning of | |
1620 | * the buffer to head pointer. | |
1621 | * | |
817d6d3b | 1622 | * Called under the tty->atomic_read_lock sem |
1da177e4 LT |
1623 | * |
1624 | */ | |
4edf1827 | 1625 | |
33f0f88f | 1626 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1627 | unsigned char __user **b, |
1628 | size_t *nr) | |
1629 | ||
1630 | { | |
1631 | int retval; | |
1632 | size_t n; | |
1633 | unsigned long flags; | |
1634 | ||
1635 | retval = 0; | |
1636 | spin_lock_irqsave(&tty->read_lock, flags); | |
1637 | n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail); | |
1638 | n = min(*nr, n); | |
1639 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1640 | if (n) { | |
1da177e4 LT |
1641 | retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n); |
1642 | n -= retval; | |
522ed776 | 1643 | tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n); |
1da177e4 LT |
1644 | spin_lock_irqsave(&tty->read_lock, flags); |
1645 | tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1); | |
1646 | tty->read_cnt -= n; | |
26df6d13 | 1647 | /* Turn single EOF into zero-length read */ |
1648 | if (L_EXTPROC(tty) && tty->icanon && n == 1) { | |
1649 | if (!tty->read_cnt && (*b)[n-1] == EOF_CHAR(tty)) | |
1650 | n--; | |
1651 | } | |
1da177e4 LT |
1652 | spin_unlock_irqrestore(&tty->read_lock, flags); |
1653 | *b += n; | |
1654 | *nr -= n; | |
1655 | } | |
1656 | return retval; | |
1657 | } | |
1658 | ||
cc4191dc | 1659 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1660 | size_t, loff_t *); |
1da177e4 LT |
1661 | |
1662 | /** | |
1663 | * job_control - check job control | |
1664 | * @tty: tty | |
1665 | * @file: file handle | |
1666 | * | |
1667 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1668 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1669 | * error code if action should be taken. |
04f378b1 AC |
1670 | * |
1671 | * FIXME: | |
1672 | * Locking: None - redirected write test is safe, testing | |
1673 | * current->signal should possibly lock current->sighand | |
1674 | * pgrp locking ? | |
1da177e4 | 1675 | */ |
4edf1827 | 1676 | |
1da177e4 LT |
1677 | static int job_control(struct tty_struct *tty, struct file *file) |
1678 | { | |
1679 | /* Job control check -- must be done at start and after | |
1680 | every sleep (POSIX.1 7.1.1.4). */ | |
1681 | /* NOTE: not yet done after every sleep pending a thorough | |
1682 | check of the logic of this change. -- jlc */ | |
1683 | /* don't stop on /dev/console */ | |
1684 | if (file->f_op->write != redirected_tty_write && | |
1685 | current->signal->tty == tty) { | |
ab521dc0 | 1686 | if (!tty->pgrp) |
11a96d18 | 1687 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); |
ab521dc0 | 1688 | else if (task_pgrp(current) != tty->pgrp) { |
1da177e4 | 1689 | if (is_ignored(SIGTTIN) || |
3e7cd6c4 | 1690 | is_current_pgrp_orphaned()) |
1da177e4 | 1691 | return -EIO; |
ab521dc0 | 1692 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); |
040b6362 | 1693 | set_thread_flag(TIF_SIGPENDING); |
1da177e4 LT |
1694 | return -ERESTARTSYS; |
1695 | } | |
1696 | } | |
1697 | return 0; | |
1698 | } | |
4edf1827 | 1699 | |
1da177e4 LT |
1700 | |
1701 | /** | |
11a96d18 | 1702 | * n_tty_read - read function for tty |
1da177e4 LT |
1703 | * @tty: tty device |
1704 | * @file: file object | |
1705 | * @buf: userspace buffer pointer | |
1706 | * @nr: size of I/O | |
1707 | * | |
1708 | * Perform reads for the line discipline. We are guaranteed that the | |
1709 | * line discipline will not be closed under us but we may get multiple | |
1710 | * parallel readers and must handle this ourselves. We may also get | |
1711 | * a hangup. Always called in user context, may sleep. | |
1712 | * | |
1713 | * This code must be sure never to sleep through a hangup. | |
1714 | */ | |
4edf1827 | 1715 | |
11a96d18 | 1716 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1717 | unsigned char __user *buf, size_t nr) |
1718 | { | |
1719 | unsigned char __user *b = buf; | |
1720 | DECLARE_WAITQUEUE(wait, current); | |
1721 | int c; | |
1722 | int minimum, time; | |
1723 | ssize_t retval = 0; | |
1724 | ssize_t size; | |
1725 | long timeout; | |
1726 | unsigned long flags; | |
04f378b1 | 1727 | int packet; |
1da177e4 LT |
1728 | |
1729 | do_it_again: | |
1730 | ||
17b82060 | 1731 | BUG_ON(!tty->read_buf); |
1da177e4 LT |
1732 | |
1733 | c = job_control(tty, file); | |
4edf1827 | 1734 | if (c < 0) |
1da177e4 | 1735 | return c; |
4edf1827 | 1736 | |
1da177e4 LT |
1737 | minimum = time = 0; |
1738 | timeout = MAX_SCHEDULE_TIMEOUT; | |
1739 | if (!tty->icanon) { | |
1740 | time = (HZ / 10) * TIME_CHAR(tty); | |
1741 | minimum = MIN_CHAR(tty); | |
1742 | if (minimum) { | |
1743 | if (time) | |
1744 | tty->minimum_to_wake = 1; | |
1745 | else if (!waitqueue_active(&tty->read_wait) || | |
1746 | (tty->minimum_to_wake > minimum)) | |
1747 | tty->minimum_to_wake = minimum; | |
1748 | } else { | |
1749 | timeout = 0; | |
1750 | if (time) { | |
1751 | timeout = time; | |
1752 | time = 0; | |
1753 | } | |
1754 | tty->minimum_to_wake = minimum = 1; | |
1755 | } | |
1756 | } | |
1757 | ||
1758 | /* | |
1759 | * Internal serialization of reads. | |
1760 | */ | |
1761 | if (file->f_flags & O_NONBLOCK) { | |
70522e12 | 1762 | if (!mutex_trylock(&tty->atomic_read_lock)) |
1da177e4 | 1763 | return -EAGAIN; |
4edf1827 | 1764 | } else { |
70522e12 | 1765 | if (mutex_lock_interruptible(&tty->atomic_read_lock)) |
1da177e4 LT |
1766 | return -ERESTARTSYS; |
1767 | } | |
04f378b1 | 1768 | packet = tty->packet; |
1da177e4 LT |
1769 | |
1770 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
1771 | while (nr) { |
1772 | /* First test for status change. */ | |
04f378b1 | 1773 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
1774 | unsigned char cs; |
1775 | if (b != buf) | |
1776 | break; | |
04f378b1 | 1777 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
1778 | cs = tty->link->ctrl_status; |
1779 | tty->link->ctrl_status = 0; | |
04f378b1 | 1780 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 1781 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
1782 | retval = -EFAULT; |
1783 | b--; | |
1784 | break; | |
1785 | } | |
1786 | nr--; | |
1787 | break; | |
1788 | } | |
1789 | /* This statement must be first before checking for input | |
1790 | so that any interrupt will set the state back to | |
1791 | TASK_RUNNING. */ | |
1792 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 1793 | |
1da177e4 LT |
1794 | if (((minimum - (b - buf)) < tty->minimum_to_wake) && |
1795 | ((minimum - (b - buf)) >= 1)) | |
1796 | tty->minimum_to_wake = (minimum - (b - buf)); | |
4edf1827 | 1797 | |
1da177e4 LT |
1798 | if (!input_available_p(tty, 0)) { |
1799 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
1800 | retval = -EIO; | |
1801 | break; | |
1802 | } | |
1803 | if (tty_hung_up_p(file)) | |
1804 | break; | |
1805 | if (!timeout) | |
1806 | break; | |
1807 | if (file->f_flags & O_NONBLOCK) { | |
1808 | retval = -EAGAIN; | |
1809 | break; | |
1810 | } | |
1811 | if (signal_pending(current)) { | |
1812 | retval = -ERESTARTSYS; | |
1813 | break; | |
1814 | } | |
55db4c64 LT |
1815 | /* FIXME: does n_tty_set_room need locking ? */ |
1816 | n_tty_set_room(tty); | |
1da177e4 | 1817 | timeout = schedule_timeout(timeout); |
28726286 | 1818 | BUG_ON(!tty->read_buf); |
1da177e4 LT |
1819 | continue; |
1820 | } | |
1821 | __set_current_state(TASK_RUNNING); | |
1822 | ||
1823 | /* Deal with packet mode. */ | |
04f378b1 | 1824 | if (packet && b == buf) { |
522ed776 | 1825 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
1826 | retval = -EFAULT; |
1827 | b--; | |
1828 | break; | |
1829 | } | |
1830 | nr--; | |
1831 | } | |
1832 | ||
26df6d13 | 1833 | if (tty->icanon && !L_EXTPROC(tty)) { |
1da177e4 LT |
1834 | /* N.B. avoid overrun if nr == 0 */ |
1835 | while (nr && tty->read_cnt) { | |
4edf1827 | 1836 | int eol; |
1da177e4 LT |
1837 | |
1838 | eol = test_and_clear_bit(tty->read_tail, | |
1839 | tty->read_flags); | |
1840 | c = tty->read_buf[tty->read_tail]; | |
1841 | spin_lock_irqsave(&tty->read_lock, flags); | |
1842 | tty->read_tail = ((tty->read_tail+1) & | |
1843 | (N_TTY_BUF_SIZE-1)); | |
1844 | tty->read_cnt--; | |
1845 | if (eol) { | |
1846 | /* this test should be redundant: | |
1847 | * we shouldn't be reading data if | |
1848 | * canon_data is 0 | |
1849 | */ | |
1850 | if (--tty->canon_data < 0) | |
1851 | tty->canon_data = 0; | |
1852 | } | |
1853 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1854 | ||
1855 | if (!eol || (c != __DISABLED_CHAR)) { | |
522ed776 | 1856 | if (tty_put_user(tty, c, b++)) { |
1da177e4 LT |
1857 | retval = -EFAULT; |
1858 | b--; | |
1859 | break; | |
1860 | } | |
1861 | nr--; | |
1862 | } | |
522ed776 MT |
1863 | if (eol) { |
1864 | tty_audit_push(tty); | |
1da177e4 | 1865 | break; |
522ed776 | 1866 | } |
1da177e4 LT |
1867 | } |
1868 | if (retval) | |
1869 | break; | |
1870 | } else { | |
1871 | int uncopied; | |
04f378b1 AC |
1872 | /* The copy function takes the read lock and handles |
1873 | locking internally for this case */ | |
1da177e4 LT |
1874 | uncopied = copy_from_read_buf(tty, &b, &nr); |
1875 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
1876 | if (uncopied) { | |
1877 | retval = -EFAULT; | |
1878 | break; | |
1879 | } | |
1880 | } | |
1881 | ||
1882 | /* If there is enough space in the read buffer now, let the | |
1883 | * low-level driver know. We use n_tty_chars_in_buffer() to | |
1884 | * check the buffer, as it now knows about canonical mode. | |
1885 | * Otherwise, if the driver is throttled and the line is | |
1886 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
1887 | * we won't get any more characters. | |
1888 | */ | |
55db4c64 LT |
1889 | if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) { |
1890 | n_tty_set_room(tty); | |
1da177e4 | 1891 | check_unthrottle(tty); |
55db4c64 | 1892 | } |
1da177e4 LT |
1893 | |
1894 | if (b - buf >= minimum) | |
1895 | break; | |
1896 | if (time) | |
1897 | timeout = time; | |
1898 | } | |
70522e12 | 1899 | mutex_unlock(&tty->atomic_read_lock); |
1da177e4 LT |
1900 | remove_wait_queue(&tty->read_wait, &wait); |
1901 | ||
1902 | if (!waitqueue_active(&tty->read_wait)) | |
1903 | tty->minimum_to_wake = minimum; | |
1904 | ||
1905 | __set_current_state(TASK_RUNNING); | |
1906 | size = b - buf; | |
1907 | if (size) { | |
1908 | retval = size; | |
1909 | if (nr) | |
4edf1827 | 1910 | clear_bit(TTY_PUSH, &tty->flags); |
1da177e4 | 1911 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) |
bbd20759 | 1912 | goto do_it_again; |
1da177e4 | 1913 | |
55db4c64 | 1914 | n_tty_set_room(tty); |
1da177e4 LT |
1915 | return retval; |
1916 | } | |
1917 | ||
1918 | /** | |
11a96d18 | 1919 | * n_tty_write - write function for tty |
1da177e4 LT |
1920 | * @tty: tty device |
1921 | * @file: file object | |
1922 | * @buf: userspace buffer pointer | |
1923 | * @nr: size of I/O | |
1924 | * | |
a88a69c9 | 1925 | * Write function of the terminal device. This is serialized with |
1da177e4 | 1926 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
1927 | * and other such events. Since the receive code will echo characters, |
1928 | * thus calling driver write methods, the output_lock is used in | |
1929 | * the output processing functions called here as well as in the | |
1930 | * echo processing function to protect the column state and space | |
1931 | * left in the buffer. | |
1da177e4 LT |
1932 | * |
1933 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
1934 | * |
1935 | * Locking: output_lock to protect column state and space left | |
1936 | * (note that the process_output*() functions take this | |
1937 | * lock themselves) | |
1da177e4 | 1938 | */ |
4edf1827 | 1939 | |
11a96d18 | 1940 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 1941 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
1942 | { |
1943 | const unsigned char *b = buf; | |
1944 | DECLARE_WAITQUEUE(wait, current); | |
1945 | int c; | |
1946 | ssize_t retval = 0; | |
1947 | ||
1948 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
1949 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
1950 | retval = tty_check_change(tty); | |
1951 | if (retval) | |
1952 | return retval; | |
1953 | } | |
1954 | ||
a88a69c9 JP |
1955 | /* Write out any echoed characters that are still pending */ |
1956 | process_echoes(tty); | |
300a6204 | 1957 | |
1da177e4 LT |
1958 | add_wait_queue(&tty->write_wait, &wait); |
1959 | while (1) { | |
1960 | set_current_state(TASK_INTERRUPTIBLE); | |
1961 | if (signal_pending(current)) { | |
1962 | retval = -ERESTARTSYS; | |
1963 | break; | |
1964 | } | |
1965 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
1966 | retval = -EIO; | |
1967 | break; | |
1968 | } | |
1969 | if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
1970 | while (nr > 0) { | |
a88a69c9 | 1971 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
1972 | if (num < 0) { |
1973 | if (num == -EAGAIN) | |
1974 | break; | |
1975 | retval = num; | |
1976 | goto break_out; | |
1977 | } | |
1978 | b += num; | |
1979 | nr -= num; | |
1980 | if (nr == 0) | |
1981 | break; | |
1982 | c = *b; | |
a88a69c9 | 1983 | if (process_output(c, tty) < 0) |
1da177e4 LT |
1984 | break; |
1985 | b++; nr--; | |
1986 | } | |
f34d7a5b AC |
1987 | if (tty->ops->flush_chars) |
1988 | tty->ops->flush_chars(tty); | |
1da177e4 | 1989 | } else { |
d6afe27b | 1990 | while (nr > 0) { |
f34d7a5b | 1991 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
1992 | if (c < 0) { |
1993 | retval = c; | |
1994 | goto break_out; | |
1995 | } | |
1996 | if (!c) | |
1997 | break; | |
1998 | b += c; | |
1999 | nr -= c; | |
1da177e4 | 2000 | } |
1da177e4 LT |
2001 | } |
2002 | if (!nr) | |
2003 | break; | |
2004 | if (file->f_flags & O_NONBLOCK) { | |
2005 | retval = -EAGAIN; | |
2006 | break; | |
2007 | } | |
2008 | schedule(); | |
2009 | } | |
2010 | break_out: | |
2011 | __set_current_state(TASK_RUNNING); | |
2012 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2013 | if (b - buf != nr && tty->fasync) |
2014 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
1da177e4 LT |
2015 | return (b - buf) ? b - buf : retval; |
2016 | } | |
2017 | ||
2018 | /** | |
11a96d18 | 2019 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2020 | * @tty: terminal device |
2021 | * @file: file accessing it | |
2022 | * @wait: poll table | |
2023 | * | |
2024 | * Called when the line discipline is asked to poll() for data or | |
2025 | * for special events. This code is not serialized with respect to | |
2026 | * other events save open/close. | |
2027 | * | |
2028 | * This code must be sure never to sleep through a hangup. | |
2029 | * Called without the kernel lock held - fine | |
1da177e4 | 2030 | */ |
4edf1827 | 2031 | |
11a96d18 | 2032 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2033 | poll_table *wait) |
1da177e4 LT |
2034 | { |
2035 | unsigned int mask = 0; | |
2036 | ||
2037 | poll_wait(file, &tty->read_wait, wait); | |
2038 | poll_wait(file, &tty->write_wait, wait); | |
2039 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2040 | mask |= POLLIN | POLLRDNORM; | |
2041 | if (tty->packet && tty->link->ctrl_status) | |
2042 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2043 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2044 | mask |= POLLHUP; | |
2045 | if (tty_hung_up_p(file)) | |
2046 | mask |= POLLHUP; | |
2047 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2048 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
2049 | tty->minimum_to_wake = MIN_CHAR(tty); | |
2050 | else | |
2051 | tty->minimum_to_wake = 1; | |
2052 | } | |
f34d7a5b AC |
2053 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2054 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2055 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2056 | mask |= POLLOUT | POLLWRNORM; |
2057 | return mask; | |
2058 | } | |
2059 | ||
47afa7a5 AC |
2060 | static unsigned long inq_canon(struct tty_struct *tty) |
2061 | { | |
2062 | int nr, head, tail; | |
2063 | ||
17b82060 | 2064 | if (!tty->canon_data) |
47afa7a5 AC |
2065 | return 0; |
2066 | head = tty->canon_head; | |
2067 | tail = tty->read_tail; | |
2068 | nr = (head - tail) & (N_TTY_BUF_SIZE-1); | |
2069 | /* Skip EOF-chars.. */ | |
2070 | while (head != tail) { | |
2071 | if (test_bit(tail, tty->read_flags) && | |
2072 | tty->read_buf[tail] == __DISABLED_CHAR) | |
2073 | nr--; | |
2074 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
2075 | } | |
2076 | return nr; | |
2077 | } | |
2078 | ||
2079 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2080 | unsigned int cmd, unsigned long arg) | |
2081 | { | |
2082 | int retval; | |
2083 | ||
2084 | switch (cmd) { | |
2085 | case TIOCOUTQ: | |
2086 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2087 | case TIOCINQ: | |
17b82060 | 2088 | /* FIXME: Locking */ |
47afa7a5 AC |
2089 | retval = tty->read_cnt; |
2090 | if (L_ICANON(tty)) | |
2091 | retval = inq_canon(tty); | |
2092 | return put_user(retval, (unsigned int __user *) arg); | |
2093 | default: | |
2094 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2095 | } | |
2096 | } | |
2097 | ||
a352def2 | 2098 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2099 | .magic = TTY_LDISC_MAGIC, |
2100 | .name = "n_tty", | |
2101 | .open = n_tty_open, | |
2102 | .close = n_tty_close, | |
2103 | .flush_buffer = n_tty_flush_buffer, | |
2104 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2105 | .read = n_tty_read, |
2106 | .write = n_tty_write, | |
e10cc1df PF |
2107 | .ioctl = n_tty_ioctl, |
2108 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2109 | .poll = n_tty_poll, |
e10cc1df PF |
2110 | .receive_buf = n_tty_receive_buf, |
2111 | .write_wakeup = n_tty_write_wakeup | |
1da177e4 | 2112 | }; |
572b9adb RG |
2113 | |
2114 | /** | |
2115 | * n_tty_inherit_ops - inherit N_TTY methods | |
2116 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2117 | * | |
2118 | * Used by a generic struct tty_ldisc_ops to easily inherit N_TTY | |
2119 | * methods. | |
2120 | */ | |
2121 | ||
2122 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2123 | { | |
2124 | *ops = tty_ldisc_N_TTY; | |
2125 | ops->owner = NULL; | |
2126 | ops->refcount = ops->flags = 0; | |
2127 | } | |
2128 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |