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 | 84 | static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty) |
1da177e4 LT |
85 | { |
86 | if (tty->read_cnt < N_TTY_BUF_SIZE) { | |
87 | tty->read_buf[tty->read_head] = c; | |
88 | tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1); | |
89 | tty->read_cnt++; | |
90 | } | |
91 | } | |
92 | ||
17b82060 AC |
93 | /** |
94 | * put_tty_queue - add character to tty | |
95 | * @c: character | |
96 | * @tty: tty device | |
97 | * | |
98 | * Add a character to the tty read_buf queue. This is done under the | |
99 | * read_lock to serialize character addition and also to protect us | |
100 | * against parallel reads or flushes | |
101 | */ | |
102 | ||
33f0f88f | 103 | static void put_tty_queue(unsigned char c, struct tty_struct *tty) |
1da177e4 LT |
104 | { |
105 | unsigned long flags; | |
106 | /* | |
107 | * The problem of stomping on the buffers ends here. | |
108 | * Why didn't anyone see this one coming? --AJK | |
109 | */ | |
110 | spin_lock_irqsave(&tty->read_lock, flags); | |
111 | put_tty_queue_nolock(c, tty); | |
112 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
113 | } | |
114 | ||
115 | /** | |
116 | * check_unthrottle - allow new receive data | |
117 | * @tty; tty device | |
118 | * | |
17b82060 AC |
119 | * Check whether to call the driver unthrottle functions |
120 | * | |
70522e12 | 121 | * Can sleep, may be called under the atomic_read_lock mutex but |
1da177e4 LT |
122 | * this is not guaranteed. |
123 | */ | |
4edf1827 | 124 | static void check_unthrottle(struct tty_struct *tty) |
1da177e4 | 125 | { |
39c2e60f AC |
126 | if (tty->count) |
127 | tty_unthrottle(tty); | |
1da177e4 LT |
128 | } |
129 | ||
130 | /** | |
131 | * reset_buffer_flags - reset buffer state | |
132 | * @tty: terminal to reset | |
133 | * | |
4edf1827 | 134 | * Reset the read buffer counters, clear the flags, |
1da177e4 LT |
135 | * and make sure the driver is unthrottled. Called |
136 | * from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 AC |
137 | * |
138 | * Locking: tty_read_lock for read fields. | |
1da177e4 | 139 | */ |
a88a69c9 | 140 | |
1da177e4 LT |
141 | static void reset_buffer_flags(struct tty_struct *tty) |
142 | { | |
143 | unsigned long flags; | |
144 | ||
145 | spin_lock_irqsave(&tty->read_lock, flags); | |
146 | tty->read_head = tty->read_tail = tty->read_cnt = 0; | |
147 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
a88a69c9 JP |
148 | |
149 | mutex_lock(&tty->echo_lock); | |
150 | tty->echo_pos = tty->echo_cnt = tty->echo_overrun = 0; | |
151 | mutex_unlock(&tty->echo_lock); | |
152 | ||
1da177e4 LT |
153 | tty->canon_head = tty->canon_data = tty->erasing = 0; |
154 | memset(&tty->read_flags, 0, sizeof tty->read_flags); | |
155 | check_unthrottle(tty); | |
156 | } | |
157 | ||
158 | /** | |
159 | * n_tty_flush_buffer - clean input queue | |
160 | * @tty: terminal device | |
161 | * | |
162 | * Flush the input buffer. Called when the line discipline is | |
163 | * being closed, when the tty layer wants the buffer flushed (eg | |
164 | * at hangup) or when the N_TTY line discipline internally has to | |
165 | * clean the pending queue (for example some signals). | |
166 | * | |
17b82060 | 167 | * Locking: ctrl_lock, read_lock. |
1da177e4 | 168 | */ |
4edf1827 AC |
169 | |
170 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 171 | { |
04f378b1 | 172 | unsigned long flags; |
1da177e4 LT |
173 | /* clear everything and unthrottle the driver */ |
174 | reset_buffer_flags(tty); | |
4edf1827 | 175 | |
1da177e4 LT |
176 | if (!tty->link) |
177 | return; | |
178 | ||
04f378b1 | 179 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
1da177e4 LT |
180 | if (tty->link->packet) { |
181 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
182 | wake_up_interruptible(&tty->link->read_wait); | |
183 | } | |
04f378b1 | 184 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1da177e4 LT |
185 | } |
186 | ||
187 | /** | |
188 | * n_tty_chars_in_buffer - report available bytes | |
189 | * @tty: tty device | |
190 | * | |
191 | * Report the number of characters buffered to be delivered to user | |
4edf1827 | 192 | * at this instant in time. |
17b82060 AC |
193 | * |
194 | * Locking: read_lock | |
1da177e4 | 195 | */ |
4edf1827 | 196 | |
1da177e4 LT |
197 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
198 | { | |
199 | unsigned long flags; | |
200 | ssize_t n = 0; | |
201 | ||
202 | spin_lock_irqsave(&tty->read_lock, flags); | |
203 | if (!tty->icanon) { | |
204 | n = tty->read_cnt; | |
205 | } else if (tty->canon_data) { | |
206 | n = (tty->canon_head > tty->read_tail) ? | |
207 | tty->canon_head - tty->read_tail : | |
208 | tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail); | |
209 | } | |
210 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
211 | return n; | |
212 | } | |
213 | ||
214 | /** | |
215 | * is_utf8_continuation - utf8 multibyte check | |
216 | * @c: byte to check | |
217 | * | |
218 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
219 | * character. We use this to correctly compute the on screen size | |
220 | * of the character when printing | |
221 | */ | |
4edf1827 | 222 | |
1da177e4 LT |
223 | static inline int is_utf8_continuation(unsigned char c) |
224 | { | |
225 | return (c & 0xc0) == 0x80; | |
226 | } | |
227 | ||
228 | /** | |
229 | * is_continuation - multibyte check | |
230 | * @c: byte to check | |
231 | * | |
232 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
233 | * character and the terminal is in unicode mode. | |
234 | */ | |
4edf1827 | 235 | |
1da177e4 LT |
236 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
237 | { | |
238 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
239 | } | |
240 | ||
241 | /** | |
a88a69c9 | 242 | * do_output_char - output one character |
1da177e4 LT |
243 | * @c: character (or partial unicode symbol) |
244 | * @tty: terminal device | |
a88a69c9 | 245 | * @space: space available in tty driver write buffer |
1da177e4 | 246 | * |
a88a69c9 JP |
247 | * This is a helper function that handles one output character |
248 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
249 | * doing OPOST processing and putting the results in the |
250 | * tty driver's write buffer. | |
a88a69c9 JP |
251 | * |
252 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
253 | * and NLDLY. They simply aren't relevant in the world today. | |
254 | * If you ever need them, add them here. | |
1da177e4 | 255 | * |
a88a69c9 JP |
256 | * Returns the number of bytes of buffer space used or -1 if |
257 | * no space left. | |
258 | * | |
259 | * Locking: should be called under the output_lock to protect | |
260 | * the column state and space left in the buffer | |
1da177e4 | 261 | */ |
4edf1827 | 262 | |
a88a69c9 | 263 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 264 | { |
a88a69c9 | 265 | int spaces; |
1da177e4 | 266 | |
1da177e4 LT |
267 | if (!space) |
268 | return -1; | |
300a6204 | 269 | |
a88a69c9 JP |
270 | switch (c) { |
271 | case '\n': | |
272 | if (O_ONLRET(tty)) | |
273 | tty->column = 0; | |
274 | if (O_ONLCR(tty)) { | |
275 | if (space < 2) | |
276 | return -1; | |
1da177e4 | 277 | tty->canon_column = tty->column = 0; |
37f81fa1 | 278 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
279 | return 2; |
280 | } | |
281 | tty->canon_column = tty->column; | |
282 | break; | |
283 | case '\r': | |
284 | if (O_ONOCR(tty) && tty->column == 0) | |
285 | return 0; | |
286 | if (O_OCRNL(tty)) { | |
287 | c = '\n'; | |
288 | if (O_ONLRET(tty)) | |
289 | tty->canon_column = tty->column = 0; | |
1da177e4 | 290 | break; |
a88a69c9 JP |
291 | } |
292 | tty->canon_column = tty->column = 0; | |
293 | break; | |
294 | case '\t': | |
295 | spaces = 8 - (tty->column & 7); | |
296 | if (O_TABDLY(tty) == XTABS) { | |
297 | if (space < spaces) | |
298 | return -1; | |
1da177e4 | 299 | tty->column += spaces; |
a88a69c9 JP |
300 | tty->ops->write(tty, " ", spaces); |
301 | return spaces; | |
1da177e4 | 302 | } |
a88a69c9 JP |
303 | tty->column += spaces; |
304 | break; | |
305 | case '\b': | |
306 | if (tty->column > 0) | |
307 | tty->column--; | |
308 | break; | |
309 | default: | |
a59c0d6f JP |
310 | if (!iscntrl(c)) { |
311 | if (O_OLCUC(tty)) | |
312 | c = toupper(c); | |
313 | if (!is_continuation(c, tty)) | |
314 | tty->column++; | |
315 | } | |
a88a69c9 | 316 | break; |
1da177e4 | 317 | } |
a88a69c9 | 318 | |
f34d7a5b | 319 | tty_put_char(tty, c); |
a88a69c9 JP |
320 | return 1; |
321 | } | |
322 | ||
323 | /** | |
324 | * process_output - output post processor | |
325 | * @c: character (or partial unicode symbol) | |
326 | * @tty: terminal device | |
327 | * | |
ee5aa7b8 JP |
328 | * Output one character with OPOST processing. |
329 | * Returns -1 when the output device is full and the character | |
330 | * must be retried. | |
a88a69c9 JP |
331 | * |
332 | * Locking: output_lock to protect column state and space left | |
333 | * (also, this is called from n_tty_write under the | |
334 | * tty layer write lock) | |
335 | */ | |
336 | ||
337 | static int process_output(unsigned char c, struct tty_struct *tty) | |
338 | { | |
339 | int space, retval; | |
340 | ||
341 | mutex_lock(&tty->output_lock); | |
342 | ||
343 | space = tty_write_room(tty); | |
344 | retval = do_output_char(c, tty, space); | |
345 | ||
346 | mutex_unlock(&tty->output_lock); | |
347 | if (retval < 0) | |
348 | return -1; | |
349 | else | |
350 | return 0; | |
1da177e4 LT |
351 | } |
352 | ||
353 | /** | |
a88a69c9 | 354 | * process_output_block - block post processor |
1da177e4 | 355 | * @tty: terminal device |
ee5aa7b8 JP |
356 | * @buf: character buffer |
357 | * @nr: number of bytes to output | |
358 | * | |
359 | * Output a block of characters with OPOST processing. | |
360 | * Returns the number of characters output. | |
1da177e4 LT |
361 | * |
362 | * This path is used to speed up block console writes, among other | |
363 | * things when processing blocks of output data. It handles only | |
364 | * the simple cases normally found and helps to generate blocks of | |
365 | * symbols for the console driver and thus improve performance. | |
366 | * | |
a88a69c9 JP |
367 | * Locking: output_lock to protect column state and space left |
368 | * (also, this is called from n_tty_write under the | |
369 | * tty layer write lock) | |
1da177e4 | 370 | */ |
4edf1827 | 371 | |
a88a69c9 JP |
372 | static ssize_t process_output_block(struct tty_struct *tty, |
373 | const unsigned char *buf, unsigned int nr) | |
1da177e4 LT |
374 | { |
375 | int space; | |
376 | int i; | |
377 | const unsigned char *cp; | |
378 | ||
a88a69c9 JP |
379 | mutex_lock(&tty->output_lock); |
380 | ||
f34d7a5b | 381 | space = tty_write_room(tty); |
300a6204 | 382 | if (!space) { |
a88a69c9 | 383 | mutex_unlock(&tty->output_lock); |
1da177e4 | 384 | return 0; |
a88a69c9 | 385 | } |
1da177e4 LT |
386 | if (nr > space) |
387 | nr = space; | |
388 | ||
389 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
390 | unsigned char c = *cp; |
391 | ||
392 | switch (c) { | |
1da177e4 LT |
393 | case '\n': |
394 | if (O_ONLRET(tty)) | |
395 | tty->column = 0; | |
396 | if (O_ONLCR(tty)) | |
397 | goto break_out; | |
398 | tty->canon_column = tty->column; | |
399 | break; | |
400 | case '\r': | |
401 | if (O_ONOCR(tty) && tty->column == 0) | |
402 | goto break_out; | |
403 | if (O_OCRNL(tty)) | |
404 | goto break_out; | |
405 | tty->canon_column = tty->column = 0; | |
406 | break; | |
407 | case '\t': | |
408 | goto break_out; | |
409 | case '\b': | |
410 | if (tty->column > 0) | |
411 | tty->column--; | |
412 | break; | |
413 | default: | |
a59c0d6f JP |
414 | if (!iscntrl(c)) { |
415 | if (O_OLCUC(tty)) | |
416 | goto break_out; | |
417 | if (!is_continuation(c, tty)) | |
418 | tty->column++; | |
419 | } | |
1da177e4 LT |
420 | break; |
421 | } | |
422 | } | |
423 | break_out: | |
f34d7a5b | 424 | i = tty->ops->write(tty, buf, i); |
a88a69c9 JP |
425 | |
426 | mutex_unlock(&tty->output_lock); | |
1da177e4 LT |
427 | return i; |
428 | } | |
429 | ||
a88a69c9 JP |
430 | /** |
431 | * process_echoes - write pending echo characters | |
432 | * @tty: terminal device | |
433 | * | |
434 | * Write previously buffered echo (and other ldisc-generated) | |
435 | * characters to the tty. | |
436 | * | |
437 | * Characters generated by the ldisc (including echoes) need to | |
438 | * be buffered because the driver's write buffer can fill during | |
439 | * heavy program output. Echoing straight to the driver will | |
440 | * often fail under these conditions, causing lost characters and | |
441 | * resulting mismatches of ldisc state information. | |
442 | * | |
443 | * Since the ldisc state must represent the characters actually sent | |
444 | * to the driver at the time of the write, operations like certain | |
445 | * changes in column state are also saved in the buffer and executed | |
446 | * here. | |
447 | * | |
448 | * A circular fifo buffer is used so that the most recent characters | |
449 | * are prioritized. Also, when control characters are echoed with a | |
450 | * prefixed "^", the pair is treated atomically and thus not separated. | |
451 | * | |
452 | * Locking: output_lock to protect column state and space left, | |
453 | * echo_lock to protect the echo buffer | |
454 | */ | |
455 | ||
456 | static void process_echoes(struct tty_struct *tty) | |
457 | { | |
458 | int space, nr; | |
459 | unsigned char c; | |
460 | unsigned char *cp, *buf_end; | |
461 | ||
462 | if (!tty->echo_cnt) | |
463 | return; | |
464 | ||
465 | mutex_lock(&tty->output_lock); | |
466 | mutex_lock(&tty->echo_lock); | |
467 | ||
468 | space = tty_write_room(tty); | |
469 | ||
470 | buf_end = tty->echo_buf + N_TTY_BUF_SIZE; | |
471 | cp = tty->echo_buf + tty->echo_pos; | |
472 | nr = tty->echo_cnt; | |
473 | while (nr > 0) { | |
474 | c = *cp; | |
475 | if (c == ECHO_OP_START) { | |
476 | unsigned char op; | |
477 | unsigned char *opp; | |
478 | int no_space_left = 0; | |
479 | ||
480 | /* | |
481 | * If the buffer byte is the start of a multi-byte | |
482 | * operation, get the next byte, which is either the | |
483 | * op code or a control character value. | |
484 | */ | |
485 | opp = cp + 1; | |
486 | if (opp == buf_end) | |
487 | opp -= N_TTY_BUF_SIZE; | |
488 | op = *opp; | |
300a6204 | 489 | |
a88a69c9 JP |
490 | switch (op) { |
491 | unsigned int num_chars, num_bs; | |
492 | ||
493 | case ECHO_OP_ERASE_TAB: | |
494 | if (++opp == buf_end) | |
495 | opp -= N_TTY_BUF_SIZE; | |
496 | num_chars = *opp; | |
497 | ||
498 | /* | |
499 | * Determine how many columns to go back | |
500 | * in order to erase the tab. | |
501 | * This depends on the number of columns | |
502 | * used by other characters within the tab | |
503 | * area. If this (modulo 8) count is from | |
504 | * the start of input rather than from a | |
505 | * previous tab, we offset by canon column. | |
506 | * Otherwise, tab spacing is normal. | |
507 | */ | |
508 | if (!(num_chars & 0x80)) | |
509 | num_chars += tty->canon_column; | |
510 | num_bs = 8 - (num_chars & 7); | |
511 | ||
512 | if (num_bs > space) { | |
513 | no_space_left = 1; | |
514 | break; | |
515 | } | |
516 | space -= num_bs; | |
517 | while (num_bs--) { | |
518 | tty_put_char(tty, '\b'); | |
519 | if (tty->column > 0) | |
520 | tty->column--; | |
521 | } | |
522 | cp += 3; | |
523 | nr -= 3; | |
524 | break; | |
525 | ||
526 | case ECHO_OP_SET_CANON_COL: | |
527 | tty->canon_column = tty->column; | |
528 | cp += 2; | |
529 | nr -= 2; | |
530 | break; | |
531 | ||
532 | case ECHO_OP_MOVE_BACK_COL: | |
533 | if (tty->column > 0) | |
534 | tty->column--; | |
535 | cp += 2; | |
536 | nr -= 2; | |
537 | break; | |
538 | ||
539 | case ECHO_OP_START: | |
540 | /* This is an escaped echo op start code */ | |
541 | if (!space) { | |
542 | no_space_left = 1; | |
543 | break; | |
544 | } | |
545 | tty_put_char(tty, ECHO_OP_START); | |
546 | tty->column++; | |
547 | space--; | |
548 | cp += 2; | |
549 | nr -= 2; | |
550 | break; | |
551 | ||
552 | default: | |
a88a69c9 | 553 | /* |
62b26358 JP |
554 | * If the op is not a special byte code, |
555 | * it is a ctrl char tagged to be echoed | |
556 | * as "^X" (where X is the letter | |
557 | * representing the control char). | |
558 | * Note that we must ensure there is | |
559 | * enough space for the whole ctrl pair. | |
560 | * | |
a88a69c9 | 561 | */ |
62b26358 JP |
562 | if (space < 2) { |
563 | no_space_left = 1; | |
564 | break; | |
565 | } | |
566 | tty_put_char(tty, '^'); | |
567 | tty_put_char(tty, op ^ 0100); | |
568 | tty->column += 2; | |
569 | space -= 2; | |
a88a69c9 JP |
570 | cp += 2; |
571 | nr -= 2; | |
572 | } | |
573 | ||
574 | if (no_space_left) | |
575 | break; | |
576 | } else { | |
ee5aa7b8 JP |
577 | if (O_OPOST(tty) && |
578 | !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
579 | int retval = do_output_char(c, tty, space); | |
580 | if (retval < 0) | |
581 | break; | |
582 | space -= retval; | |
583 | } else { | |
584 | if (!space) | |
585 | break; | |
586 | tty_put_char(tty, c); | |
587 | space -= 1; | |
588 | } | |
a88a69c9 JP |
589 | cp += 1; |
590 | nr -= 1; | |
591 | } | |
592 | ||
593 | /* When end of circular buffer reached, wrap around */ | |
594 | if (cp >= buf_end) | |
595 | cp -= N_TTY_BUF_SIZE; | |
596 | } | |
597 | ||
598 | if (nr == 0) { | |
599 | tty->echo_pos = 0; | |
600 | tty->echo_cnt = 0; | |
601 | tty->echo_overrun = 0; | |
602 | } else { | |
603 | int num_processed = tty->echo_cnt - nr; | |
604 | tty->echo_pos += num_processed; | |
605 | tty->echo_pos &= N_TTY_BUF_SIZE - 1; | |
606 | tty->echo_cnt = nr; | |
607 | if (num_processed > 0) | |
608 | tty->echo_overrun = 0; | |
609 | } | |
610 | ||
611 | mutex_unlock(&tty->echo_lock); | |
612 | mutex_unlock(&tty->output_lock); | |
613 | ||
614 | if (tty->ops->flush_chars) | |
615 | tty->ops->flush_chars(tty); | |
616 | } | |
617 | ||
618 | /** | |
619 | * add_echo_byte - add a byte to the echo buffer | |
620 | * @c: unicode byte to echo | |
621 | * @tty: terminal device | |
622 | * | |
623 | * Add a character or operation byte to the echo buffer. | |
624 | * | |
625 | * Should be called under the echo lock to protect the echo buffer. | |
626 | */ | |
627 | ||
628 | static void add_echo_byte(unsigned char c, struct tty_struct *tty) | |
629 | { | |
630 | int new_byte_pos; | |
631 | ||
632 | if (tty->echo_cnt == N_TTY_BUF_SIZE) { | |
633 | /* Circular buffer is already at capacity */ | |
634 | new_byte_pos = tty->echo_pos; | |
635 | ||
636 | /* | |
637 | * Since the buffer start position needs to be advanced, | |
638 | * be sure to step by a whole operation byte group. | |
639 | */ | |
300a6204 | 640 | if (tty->echo_buf[tty->echo_pos] == ECHO_OP_START) { |
a88a69c9 JP |
641 | if (tty->echo_buf[(tty->echo_pos + 1) & |
642 | (N_TTY_BUF_SIZE - 1)] == | |
643 | ECHO_OP_ERASE_TAB) { | |
644 | tty->echo_pos += 3; | |
645 | tty->echo_cnt -= 2; | |
646 | } else { | |
647 | tty->echo_pos += 2; | |
648 | tty->echo_cnt -= 1; | |
649 | } | |
650 | } else { | |
651 | tty->echo_pos++; | |
652 | } | |
653 | tty->echo_pos &= N_TTY_BUF_SIZE - 1; | |
654 | ||
655 | tty->echo_overrun = 1; | |
656 | } else { | |
657 | new_byte_pos = tty->echo_pos + tty->echo_cnt; | |
658 | new_byte_pos &= N_TTY_BUF_SIZE - 1; | |
659 | tty->echo_cnt++; | |
660 | } | |
661 | ||
662 | tty->echo_buf[new_byte_pos] = c; | |
663 | } | |
664 | ||
665 | /** | |
666 | * echo_move_back_col - add operation to move back a column | |
667 | * @tty: terminal device | |
668 | * | |
669 | * Add an operation to the echo buffer to move back one column. | |
670 | * | |
671 | * Locking: echo_lock to protect the echo buffer | |
672 | */ | |
673 | ||
674 | static void echo_move_back_col(struct tty_struct *tty) | |
675 | { | |
676 | mutex_lock(&tty->echo_lock); | |
677 | ||
678 | add_echo_byte(ECHO_OP_START, tty); | |
679 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty); | |
680 | ||
681 | mutex_unlock(&tty->echo_lock); | |
682 | } | |
683 | ||
684 | /** | |
685 | * echo_set_canon_col - add operation to set the canon column | |
686 | * @tty: terminal device | |
687 | * | |
688 | * Add an operation to the echo buffer to set the canon column | |
689 | * to the current column. | |
690 | * | |
691 | * Locking: echo_lock to protect the echo buffer | |
692 | */ | |
693 | ||
694 | static void echo_set_canon_col(struct tty_struct *tty) | |
695 | { | |
696 | mutex_lock(&tty->echo_lock); | |
697 | ||
698 | add_echo_byte(ECHO_OP_START, tty); | |
699 | add_echo_byte(ECHO_OP_SET_CANON_COL, tty); | |
700 | ||
701 | mutex_unlock(&tty->echo_lock); | |
702 | } | |
703 | ||
704 | /** | |
705 | * echo_erase_tab - add operation to erase a tab | |
706 | * @num_chars: number of character columns already used | |
707 | * @after_tab: true if num_chars starts after a previous tab | |
708 | * @tty: terminal device | |
709 | * | |
710 | * Add an operation to the echo buffer to erase a tab. | |
711 | * | |
712 | * Called by the eraser function, which knows how many character | |
713 | * columns have been used since either a previous tab or the start | |
714 | * of input. This information will be used later, along with | |
715 | * canon column (if applicable), to go back the correct number | |
716 | * of columns. | |
717 | * | |
718 | * Locking: echo_lock to protect the echo buffer | |
719 | */ | |
720 | ||
721 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
722 | struct tty_struct *tty) | |
723 | { | |
724 | mutex_lock(&tty->echo_lock); | |
725 | ||
726 | add_echo_byte(ECHO_OP_START, tty); | |
727 | add_echo_byte(ECHO_OP_ERASE_TAB, tty); | |
728 | ||
729 | /* We only need to know this modulo 8 (tab spacing) */ | |
730 | num_chars &= 7; | |
731 | ||
732 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
733 | if (after_tab) | |
734 | num_chars |= 0x80; | |
300a6204 | 735 | |
a88a69c9 JP |
736 | add_echo_byte(num_chars, tty); |
737 | ||
738 | mutex_unlock(&tty->echo_lock); | |
739 | } | |
740 | ||
741 | /** | |
742 | * echo_char_raw - echo a character raw | |
743 | * @c: unicode byte to echo | |
744 | * @tty: terminal device | |
745 | * | |
746 | * Echo user input back onto the screen. This must be called only when | |
747 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
748 | * | |
749 | * This variant does not treat control characters specially. | |
750 | * | |
751 | * Locking: echo_lock to protect the echo buffer | |
752 | */ | |
753 | ||
754 | static void echo_char_raw(unsigned char c, struct tty_struct *tty) | |
755 | { | |
756 | mutex_lock(&tty->echo_lock); | |
757 | ||
758 | if (c == ECHO_OP_START) { | |
759 | add_echo_byte(ECHO_OP_START, tty); | |
760 | add_echo_byte(ECHO_OP_START, tty); | |
761 | } else { | |
762 | add_echo_byte(c, tty); | |
763 | } | |
764 | ||
765 | mutex_unlock(&tty->echo_lock); | |
766 | } | |
1da177e4 | 767 | |
1da177e4 | 768 | /** |
a88a69c9 | 769 | * echo_char - echo a character |
1da177e4 LT |
770 | * @c: unicode byte to echo |
771 | * @tty: terminal device | |
772 | * | |
4edf1827 | 773 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 774 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 775 | * |
62b26358 JP |
776 | * This variant tags control characters to be echoed as "^X" |
777 | * (where X is the letter representing the control char). | |
a88a69c9 JP |
778 | * |
779 | * Locking: echo_lock to protect the echo buffer | |
1da177e4 LT |
780 | */ |
781 | ||
782 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
783 | { | |
a88a69c9 JP |
784 | mutex_lock(&tty->echo_lock); |
785 | ||
786 | if (c == ECHO_OP_START) { | |
787 | add_echo_byte(ECHO_OP_START, tty); | |
788 | add_echo_byte(ECHO_OP_START, tty); | |
789 | } else { | |
62b26358 | 790 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
a88a69c9 JP |
791 | add_echo_byte(ECHO_OP_START, tty); |
792 | add_echo_byte(c, tty); | |
793 | } | |
794 | ||
795 | mutex_unlock(&tty->echo_lock); | |
1da177e4 LT |
796 | } |
797 | ||
17b82060 | 798 | /** |
a88a69c9 | 799 | * finish_erasing - complete erase |
17b82060 | 800 | * @tty: tty doing the erase |
17b82060 | 801 | */ |
a88a69c9 | 802 | |
1da177e4 LT |
803 | static inline void finish_erasing(struct tty_struct *tty) |
804 | { | |
805 | if (tty->erasing) { | |
a88a69c9 | 806 | echo_char_raw('/', tty); |
1da177e4 LT |
807 | tty->erasing = 0; |
808 | } | |
809 | } | |
810 | ||
811 | /** | |
812 | * eraser - handle erase function | |
813 | * @c: character input | |
814 | * @tty: terminal device | |
815 | * | |
3a4fa0a2 | 816 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
817 | * present in the stream from the driver layer. Handles the complexities |
818 | * of UTF-8 multibyte symbols. | |
17b82060 | 819 | * |
a88a69c9 | 820 | * Locking: read_lock for tty buffers |
1da177e4 | 821 | */ |
4edf1827 | 822 | |
1da177e4 LT |
823 | static void eraser(unsigned char c, struct tty_struct *tty) |
824 | { | |
825 | enum { ERASE, WERASE, KILL } kill_type; | |
826 | int head, seen_alnums, cnt; | |
827 | unsigned long flags; | |
828 | ||
17b82060 | 829 | /* FIXME: locking needed ? */ |
1da177e4 | 830 | if (tty->read_head == tty->canon_head) { |
7e94b1d9 | 831 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
832 | return; |
833 | } | |
834 | if (c == ERASE_CHAR(tty)) | |
835 | kill_type = ERASE; | |
836 | else if (c == WERASE_CHAR(tty)) | |
837 | kill_type = WERASE; | |
838 | else { | |
839 | if (!L_ECHO(tty)) { | |
840 | spin_lock_irqsave(&tty->read_lock, flags); | |
841 | tty->read_cnt -= ((tty->read_head - tty->canon_head) & | |
842 | (N_TTY_BUF_SIZE - 1)); | |
843 | tty->read_head = tty->canon_head; | |
844 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
845 | return; | |
846 | } | |
847 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
848 | spin_lock_irqsave(&tty->read_lock, flags); | |
849 | tty->read_cnt -= ((tty->read_head - tty->canon_head) & | |
850 | (N_TTY_BUF_SIZE - 1)); | |
851 | tty->read_head = tty->canon_head; | |
852 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
853 | finish_erasing(tty); | |
854 | echo_char(KILL_CHAR(tty), tty); | |
855 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
856 | if (L_ECHOK(tty)) | |
a88a69c9 | 857 | echo_char_raw('\n', tty); |
1da177e4 LT |
858 | return; |
859 | } | |
860 | kill_type = KILL; | |
861 | } | |
862 | ||
863 | seen_alnums = 0; | |
17b82060 | 864 | /* FIXME: Locking ?? */ |
1da177e4 LT |
865 | while (tty->read_head != tty->canon_head) { |
866 | head = tty->read_head; | |
867 | ||
868 | /* erase a single possibly multibyte character */ | |
869 | do { | |
870 | head = (head - 1) & (N_TTY_BUF_SIZE-1); | |
871 | c = tty->read_buf[head]; | |
872 | } while (is_continuation(c, tty) && head != tty->canon_head); | |
873 | ||
874 | /* do not partially erase */ | |
875 | if (is_continuation(c, tty)) | |
876 | break; | |
877 | ||
878 | if (kill_type == WERASE) { | |
879 | /* Equivalent to BSD's ALTWERASE. */ | |
880 | if (isalnum(c) || c == '_') | |
881 | seen_alnums++; | |
882 | else if (seen_alnums) | |
883 | break; | |
884 | } | |
885 | cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1); | |
886 | spin_lock_irqsave(&tty->read_lock, flags); | |
887 | tty->read_head = head; | |
888 | tty->read_cnt -= cnt; | |
889 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
890 | if (L_ECHO(tty)) { | |
891 | if (L_ECHOPRT(tty)) { | |
892 | if (!tty->erasing) { | |
a88a69c9 | 893 | echo_char_raw('\\', tty); |
1da177e4 LT |
894 | tty->erasing = 1; |
895 | } | |
896 | /* if cnt > 1, output a multi-byte character */ | |
897 | echo_char(c, tty); | |
898 | while (--cnt > 0) { | |
899 | head = (head+1) & (N_TTY_BUF_SIZE-1); | |
a88a69c9 JP |
900 | echo_char_raw(tty->read_buf[head], tty); |
901 | echo_move_back_col(tty); | |
1da177e4 LT |
902 | } |
903 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
904 | echo_char(ERASE_CHAR(tty), tty); | |
905 | } else if (c == '\t') { | |
a88a69c9 JP |
906 | unsigned int num_chars = 0; |
907 | int after_tab = 0; | |
908 | unsigned long tail = tty->read_head; | |
909 | ||
910 | /* | |
911 | * Count the columns used for characters | |
912 | * since the start of input or after a | |
913 | * previous tab. | |
914 | * This info is used to go back the correct | |
915 | * number of columns. | |
916 | */ | |
917 | while (tail != tty->canon_head) { | |
918 | tail = (tail-1) & (N_TTY_BUF_SIZE-1); | |
1da177e4 | 919 | c = tty->read_buf[tail]; |
a88a69c9 JP |
920 | if (c == '\t') { |
921 | after_tab = 1; | |
922 | break; | |
300a6204 | 923 | } else if (iscntrl(c)) { |
1da177e4 | 924 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
925 | num_chars += 2; |
926 | } else if (!is_continuation(c, tty)) { | |
927 | num_chars++; | |
928 | } | |
1da177e4 | 929 | } |
a88a69c9 | 930 | echo_erase_tab(num_chars, after_tab, tty); |
1da177e4 LT |
931 | } else { |
932 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
a88a69c9 JP |
933 | echo_char_raw('\b', tty); |
934 | echo_char_raw(' ', tty); | |
935 | echo_char_raw('\b', tty); | |
1da177e4 LT |
936 | } |
937 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
a88a69c9 JP |
938 | echo_char_raw('\b', tty); |
939 | echo_char_raw(' ', tty); | |
940 | echo_char_raw('\b', tty); | |
1da177e4 LT |
941 | } |
942 | } | |
943 | } | |
944 | if (kill_type == ERASE) | |
945 | break; | |
946 | } | |
a88a69c9 | 947 | if (tty->read_head == tty->canon_head && L_ECHO(tty)) |
1da177e4 LT |
948 | finish_erasing(tty); |
949 | } | |
950 | ||
951 | /** | |
952 | * isig - handle the ISIG optio | |
953 | * @sig: signal | |
954 | * @tty: terminal | |
955 | * @flush: force flush | |
956 | * | |
957 | * Called when a signal is being sent due to terminal input. This | |
958 | * may caus terminal flushing to take place according to the termios | |
959 | * settings and character used. Called from the driver receive_buf | |
960 | * path so serialized. | |
17b82060 AC |
961 | * |
962 | * Locking: ctrl_lock, read_lock (both via flush buffer) | |
1da177e4 | 963 | */ |
4edf1827 | 964 | |
1da177e4 LT |
965 | static inline void isig(int sig, struct tty_struct *tty, int flush) |
966 | { | |
ab521dc0 EB |
967 | if (tty->pgrp) |
968 | kill_pgrp(tty->pgrp, sig, 1); | |
1da177e4 LT |
969 | if (flush || !L_NOFLSH(tty)) { |
970 | n_tty_flush_buffer(tty); | |
f34d7a5b | 971 | tty_driver_flush_buffer(tty); |
1da177e4 LT |
972 | } |
973 | } | |
974 | ||
975 | /** | |
976 | * n_tty_receive_break - handle break | |
977 | * @tty: terminal | |
978 | * | |
979 | * An RS232 break event has been hit in the incoming bitstream. This | |
980 | * can cause a variety of events depending upon the termios settings. | |
981 | * | |
982 | * Called from the receive_buf path so single threaded. | |
983 | */ | |
4edf1827 | 984 | |
1da177e4 LT |
985 | static inline void n_tty_receive_break(struct tty_struct *tty) |
986 | { | |
987 | if (I_IGNBRK(tty)) | |
988 | return; | |
989 | if (I_BRKINT(tty)) { | |
990 | isig(SIGINT, tty, 1); | |
991 | return; | |
992 | } | |
993 | if (I_PARMRK(tty)) { | |
994 | put_tty_queue('\377', tty); | |
995 | put_tty_queue('\0', tty); | |
996 | } | |
997 | put_tty_queue('\0', tty); | |
998 | wake_up_interruptible(&tty->read_wait); | |
999 | } | |
1000 | ||
1001 | /** | |
1002 | * n_tty_receive_overrun - handle overrun reporting | |
1003 | * @tty: terminal | |
1004 | * | |
1005 | * Data arrived faster than we could process it. While the tty | |
1006 | * driver has flagged this the bits that were missed are gone | |
1007 | * forever. | |
1008 | * | |
1009 | * Called from the receive_buf path so single threaded. Does not | |
1010 | * need locking as num_overrun and overrun_time are function | |
1011 | * private. | |
1012 | */ | |
4edf1827 | 1013 | |
1da177e4 LT |
1014 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1015 | { | |
1016 | char buf[64]; | |
1017 | ||
1018 | tty->num_overrun++; | |
1019 | if (time_before(tty->overrun_time, jiffies - HZ) || | |
1020 | time_after(tty->overrun_time, jiffies)) { | |
1021 | printk(KERN_WARNING "%s: %d input overrun(s)\n", | |
1022 | tty_name(tty, buf), | |
1023 | tty->num_overrun); | |
1024 | tty->overrun_time = jiffies; | |
1025 | tty->num_overrun = 0; | |
1026 | } | |
1027 | } | |
1028 | ||
1029 | /** | |
1030 | * n_tty_receive_parity_error - error notifier | |
1031 | * @tty: terminal device | |
1032 | * @c: character | |
1033 | * | |
1034 | * Process a parity error and queue the right data to indicate | |
3a4fa0a2 | 1035 | * the error case if necessary. Locking as per n_tty_receive_buf. |
1da177e4 LT |
1036 | */ |
1037 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1038 | unsigned char c) | |
1039 | { | |
4edf1827 | 1040 | if (I_IGNPAR(tty)) |
1da177e4 | 1041 | return; |
1da177e4 LT |
1042 | if (I_PARMRK(tty)) { |
1043 | put_tty_queue('\377', tty); | |
1044 | put_tty_queue('\0', tty); | |
1045 | put_tty_queue(c, tty); | |
1046 | } else if (I_INPCK(tty)) | |
1047 | put_tty_queue('\0', tty); | |
1048 | else | |
1049 | put_tty_queue(c, tty); | |
1050 | wake_up_interruptible(&tty->read_wait); | |
1051 | } | |
1052 | ||
1053 | /** | |
1054 | * n_tty_receive_char - perform processing | |
1055 | * @tty: terminal device | |
1056 | * @c: character | |
1057 | * | |
1058 | * Process an individual character of input received from the driver. | |
4edf1827 | 1059 | * This is serialized with respect to itself by the rules for the |
1da177e4 LT |
1060 | * driver above. |
1061 | */ | |
1062 | ||
1063 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1064 | { | |
1065 | unsigned long flags; | |
acc71bba | 1066 | int parmrk; |
1da177e4 LT |
1067 | |
1068 | if (tty->raw) { | |
1069 | put_tty_queue(c, tty); | |
1070 | return; | |
1071 | } | |
4edf1827 | 1072 | |
1da177e4 LT |
1073 | if (I_ISTRIP(tty)) |
1074 | c &= 0x7f; | |
1075 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1076 | c = tolower(c); |
1da177e4 | 1077 | |
26df6d13 | 1078 | if (L_EXTPROC(tty)) { |
1079 | put_tty_queue(c, tty); | |
1080 | return; | |
1081 | } | |
1082 | ||
54d2a37e | 1083 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1084 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1085 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1086 | start_tty(tty); |
a88a69c9 JP |
1087 | process_echoes(tty); |
1088 | } | |
54d2a37e | 1089 | |
1da177e4 LT |
1090 | if (tty->closing) { |
1091 | if (I_IXON(tty)) { | |
a88a69c9 | 1092 | if (c == START_CHAR(tty)) { |
1da177e4 | 1093 | start_tty(tty); |
a88a69c9 | 1094 | process_echoes(tty); |
300a6204 | 1095 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1096 | stop_tty(tty); |
1097 | } | |
1098 | return; | |
1099 | } | |
1100 | ||
1101 | /* | |
1102 | * If the previous character was LNEXT, or we know that this | |
1103 | * character is not one of the characters that we'll have to | |
1104 | * handle specially, do shortcut processing to speed things | |
1105 | * up. | |
1106 | */ | |
1107 | if (!test_bit(c, tty->process_char_map) || tty->lnext) { | |
1da177e4 | 1108 | tty->lnext = 0; |
acc71bba JP |
1109 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
1110 | if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { | |
1111 | /* beep if no space */ | |
7e94b1d9 JP |
1112 | if (L_ECHO(tty)) |
1113 | process_output('\a', tty); | |
acc71bba JP |
1114 | return; |
1115 | } | |
1116 | if (L_ECHO(tty)) { | |
1117 | finish_erasing(tty); | |
1da177e4 LT |
1118 | /* Record the column of first canon char. */ |
1119 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1120 | echo_set_canon_col(tty); |
1da177e4 | 1121 | echo_char(c, tty); |
a88a69c9 | 1122 | process_echoes(tty); |
1da177e4 | 1123 | } |
acc71bba | 1124 | if (parmrk) |
1da177e4 LT |
1125 | put_tty_queue(c, tty); |
1126 | put_tty_queue(c, tty); | |
1127 | return; | |
1128 | } | |
4edf1827 | 1129 | |
1da177e4 LT |
1130 | if (I_IXON(tty)) { |
1131 | if (c == START_CHAR(tty)) { | |
1132 | start_tty(tty); | |
a88a69c9 | 1133 | process_echoes(tty); |
1da177e4 LT |
1134 | return; |
1135 | } | |
1136 | if (c == STOP_CHAR(tty)) { | |
1137 | stop_tty(tty); | |
1138 | return; | |
1139 | } | |
1140 | } | |
575537b3 | 1141 | |
1da177e4 LT |
1142 | if (L_ISIG(tty)) { |
1143 | int signal; | |
1144 | signal = SIGINT; | |
1145 | if (c == INTR_CHAR(tty)) | |
1146 | goto send_signal; | |
1147 | signal = SIGQUIT; | |
1148 | if (c == QUIT_CHAR(tty)) | |
1149 | goto send_signal; | |
1150 | signal = SIGTSTP; | |
1151 | if (c == SUSP_CHAR(tty)) { | |
1152 | send_signal: | |
ec5b1157 | 1153 | /* |
ec5b1157 JP |
1154 | * Note that we do not use isig() here because we want |
1155 | * the order to be: | |
1156 | * 1) flush, 2) echo, 3) signal | |
1157 | */ | |
1158 | if (!L_NOFLSH(tty)) { | |
1159 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1160 | tty_driver_flush_buffer(tty); |
ec5b1157 | 1161 | } |
a88a69c9 JP |
1162 | if (I_IXON(tty)) |
1163 | start_tty(tty); | |
1164 | if (L_ECHO(tty)) { | |
ec5b1157 | 1165 | echo_char(c, tty); |
a88a69c9 JP |
1166 | process_echoes(tty); |
1167 | } | |
ec5b1157 JP |
1168 | if (tty->pgrp) |
1169 | kill_pgrp(tty->pgrp, signal, 1); | |
1da177e4 LT |
1170 | return; |
1171 | } | |
1172 | } | |
575537b3 JP |
1173 | |
1174 | if (c == '\r') { | |
1175 | if (I_IGNCR(tty)) | |
1176 | return; | |
1177 | if (I_ICRNL(tty)) | |
1178 | c = '\n'; | |
1179 | } else if (c == '\n' && I_INLCR(tty)) | |
1180 | c = '\r'; | |
1181 | ||
1da177e4 LT |
1182 | if (tty->icanon) { |
1183 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || | |
1184 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1185 | eraser(c, tty); | |
a88a69c9 | 1186 | process_echoes(tty); |
1da177e4 LT |
1187 | return; |
1188 | } | |
1189 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
1190 | tty->lnext = 1; | |
1191 | if (L_ECHO(tty)) { | |
1192 | finish_erasing(tty); | |
1193 | if (L_ECHOCTL(tty)) { | |
a88a69c9 JP |
1194 | echo_char_raw('^', tty); |
1195 | echo_char_raw('\b', tty); | |
1196 | process_echoes(tty); | |
1da177e4 LT |
1197 | } |
1198 | } | |
1199 | return; | |
1200 | } | |
1201 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1202 | L_IEXTEN(tty)) { | |
1203 | unsigned long tail = tty->canon_head; | |
1204 | ||
1205 | finish_erasing(tty); | |
1206 | echo_char(c, tty); | |
a88a69c9 | 1207 | echo_char_raw('\n', tty); |
1da177e4 LT |
1208 | while (tail != tty->read_head) { |
1209 | echo_char(tty->read_buf[tail], tty); | |
1210 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
1211 | } | |
a88a69c9 | 1212 | process_echoes(tty); |
1da177e4 LT |
1213 | return; |
1214 | } | |
1215 | if (c == '\n') { | |
acc71bba | 1216 | if (tty->read_cnt >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1217 | if (L_ECHO(tty)) |
1218 | process_output('\a', tty); | |
acc71bba JP |
1219 | return; |
1220 | } | |
1221 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
a88a69c9 JP |
1222 | echo_char_raw('\n', tty); |
1223 | process_echoes(tty); | |
1da177e4 LT |
1224 | } |
1225 | goto handle_newline; | |
1226 | } | |
1227 | if (c == EOF_CHAR(tty)) { | |
acc71bba JP |
1228 | if (tty->read_cnt >= N_TTY_BUF_SIZE) |
1229 | return; | |
4edf1827 AC |
1230 | if (tty->canon_head != tty->read_head) |
1231 | set_bit(TTY_PUSH, &tty->flags); | |
1da177e4 LT |
1232 | c = __DISABLED_CHAR; |
1233 | goto handle_newline; | |
1234 | } | |
1235 | if ((c == EOL_CHAR(tty)) || | |
1236 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1237 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1238 | ? 1 : 0; | |
1239 | if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) { | |
7e94b1d9 JP |
1240 | if (L_ECHO(tty)) |
1241 | process_output('\a', tty); | |
acc71bba JP |
1242 | return; |
1243 | } | |
1da177e4 LT |
1244 | /* |
1245 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1246 | */ | |
1247 | if (L_ECHO(tty)) { | |
1da177e4 LT |
1248 | /* Record the column of first canon char. */ |
1249 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1250 | echo_set_canon_col(tty); |
1da177e4 | 1251 | echo_char(c, tty); |
a88a69c9 | 1252 | process_echoes(tty); |
1da177e4 LT |
1253 | } |
1254 | /* | |
1255 | * XXX does PARMRK doubling happen for | |
1256 | * EOL_CHAR and EOL2_CHAR? | |
1257 | */ | |
acc71bba | 1258 | if (parmrk) |
1da177e4 LT |
1259 | put_tty_queue(c, tty); |
1260 | ||
4edf1827 | 1261 | handle_newline: |
1da177e4 LT |
1262 | spin_lock_irqsave(&tty->read_lock, flags); |
1263 | set_bit(tty->read_head, tty->read_flags); | |
1264 | put_tty_queue_nolock(c, tty); | |
1265 | tty->canon_head = tty->read_head; | |
1266 | tty->canon_data++; | |
1267 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1268 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); | |
1269 | if (waitqueue_active(&tty->read_wait)) | |
1270 | wake_up_interruptible(&tty->read_wait); | |
1271 | return; | |
1272 | } | |
1273 | } | |
4edf1827 | 1274 | |
acc71bba JP |
1275 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
1276 | if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { | |
1277 | /* beep if no space */ | |
7e94b1d9 JP |
1278 | if (L_ECHO(tty)) |
1279 | process_output('\a', tty); | |
acc71bba JP |
1280 | return; |
1281 | } | |
1282 | if (L_ECHO(tty)) { | |
1283 | finish_erasing(tty); | |
1da177e4 | 1284 | if (c == '\n') |
a88a69c9 | 1285 | echo_char_raw('\n', tty); |
1da177e4 LT |
1286 | else { |
1287 | /* Record the column of first canon char. */ | |
1288 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1289 | echo_set_canon_col(tty); |
1da177e4 LT |
1290 | echo_char(c, tty); |
1291 | } | |
a88a69c9 | 1292 | process_echoes(tty); |
1da177e4 LT |
1293 | } |
1294 | ||
acc71bba | 1295 | if (parmrk) |
1da177e4 LT |
1296 | put_tty_queue(c, tty); |
1297 | ||
1298 | put_tty_queue(c, tty); | |
4edf1827 | 1299 | } |
1da177e4 | 1300 | |
1da177e4 LT |
1301 | |
1302 | /** | |
1303 | * n_tty_write_wakeup - asynchronous I/O notifier | |
1304 | * @tty: tty device | |
1305 | * | |
1306 | * Required for the ptys, serial driver etc. since processes | |
1307 | * that attach themselves to the master and rely on ASYNC | |
1308 | * IO must be woken up | |
1309 | */ | |
1310 | ||
1311 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
1312 | { | |
ff8cb0fd | 1313 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) |
1da177e4 | 1314 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); |
1da177e4 LT |
1315 | } |
1316 | ||
1317 | /** | |
1318 | * n_tty_receive_buf - data receive | |
1319 | * @tty: terminal device | |
1320 | * @cp: buffer | |
1321 | * @fp: flag buffer | |
1322 | * @count: characters | |
1323 | * | |
1324 | * Called by the terminal driver when a block of characters has | |
1325 | * been received. This function must be called from soft contexts | |
1326 | * not from interrupt context. The driver is responsible for making | |
1327 | * calls one at a time and in order (or using flush_to_ldisc) | |
1328 | */ | |
4edf1827 | 1329 | |
b1c43f82 FB |
1330 | static unsigned int n_tty_receive_buf(struct tty_struct *tty, |
1331 | const unsigned char *cp, char *fp, int count) | |
1da177e4 LT |
1332 | { |
1333 | const unsigned char *p; | |
1334 | char *f, flags = TTY_NORMAL; | |
1335 | int i; | |
1336 | char buf[64]; | |
1337 | unsigned long cpuflags; | |
b1c43f82 FB |
1338 | int left; |
1339 | int ret = 0; | |
1da177e4 LT |
1340 | |
1341 | if (!tty->read_buf) | |
b1c43f82 | 1342 | return 0; |
1da177e4 LT |
1343 | |
1344 | if (tty->real_raw) { | |
1345 | spin_lock_irqsave(&tty->read_lock, cpuflags); | |
1346 | i = min(N_TTY_BUF_SIZE - tty->read_cnt, | |
1347 | N_TTY_BUF_SIZE - tty->read_head); | |
1348 | i = min(count, i); | |
1349 | memcpy(tty->read_buf + tty->read_head, cp, i); | |
1350 | tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1351 | tty->read_cnt += i; | |
b1c43f82 | 1352 | ret += i; |
1da177e4 LT |
1353 | cp += i; |
1354 | count -= i; | |
1355 | ||
1356 | i = min(N_TTY_BUF_SIZE - tty->read_cnt, | |
1357 | N_TTY_BUF_SIZE - tty->read_head); | |
1358 | i = min(count, i); | |
1359 | memcpy(tty->read_buf + tty->read_head, cp, i); | |
1360 | tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1361 | tty->read_cnt += i; | |
b1c43f82 | 1362 | ret += i; |
1da177e4 LT |
1363 | spin_unlock_irqrestore(&tty->read_lock, cpuflags); |
1364 | } else { | |
b1c43f82 | 1365 | ret = count; |
4edf1827 | 1366 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1367 | if (f) |
1368 | flags = *f++; | |
1369 | switch (flags) { | |
1370 | case TTY_NORMAL: | |
1371 | n_tty_receive_char(tty, *p); | |
1372 | break; | |
1373 | case TTY_BREAK: | |
1374 | n_tty_receive_break(tty); | |
1375 | break; | |
1376 | case TTY_PARITY: | |
1377 | case TTY_FRAME: | |
1378 | n_tty_receive_parity_error(tty, *p); | |
1379 | break; | |
1380 | case TTY_OVERRUN: | |
1381 | n_tty_receive_overrun(tty); | |
1382 | break; | |
1383 | default: | |
4edf1827 | 1384 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1385 | tty_name(tty, buf), flags); |
1386 | break; | |
1387 | } | |
1388 | } | |
f34d7a5b AC |
1389 | if (tty->ops->flush_chars) |
1390 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1391 | } |
1392 | ||
26df6d13 | 1393 | if ((!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) || |
1394 | L_EXTPROC(tty)) { | |
1da177e4 LT |
1395 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1396 | if (waitqueue_active(&tty->read_wait)) | |
1397 | wake_up_interruptible(&tty->read_wait); | |
1398 | } | |
1399 | ||
1400 | /* | |
1401 | * Check the remaining room for the input canonicalization | |
1402 | * mode. We don't want to throttle the driver if we're in | |
1403 | * canonical mode and don't have a newline yet! | |
1404 | */ | |
b1c43f82 FB |
1405 | left = N_TTY_BUF_SIZE - tty->read_cnt - 1; |
1406 | ||
1407 | if (left < TTY_THRESHOLD_THROTTLE) | |
39c2e60f | 1408 | tty_throttle(tty); |
b1c43f82 FB |
1409 | |
1410 | return ret; | |
1da177e4 LT |
1411 | } |
1412 | ||
1413 | int is_ignored(int sig) | |
1414 | { | |
1415 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1416 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1417 | } |
1418 | ||
1419 | /** | |
1420 | * n_tty_set_termios - termios data changed | |
1421 | * @tty: terminal | |
1422 | * @old: previous data | |
1423 | * | |
1424 | * Called by the tty layer when the user changes termios flags so | |
1425 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1426 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1427 | * guaranteed that this function will not be re-entered or in progress |
1428 | * when the ldisc is closed. | |
17b82060 AC |
1429 | * |
1430 | * Locking: Caller holds tty->termios_mutex | |
1da177e4 | 1431 | */ |
4edf1827 AC |
1432 | |
1433 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1434 | { |
47afa7a5 AC |
1435 | int canon_change = 1; |
1436 | BUG_ON(!tty); | |
1437 | ||
1438 | if (old) | |
1439 | canon_change = (old->c_lflag ^ tty->termios->c_lflag) & ICANON; | |
1440 | if (canon_change) { | |
1441 | memset(&tty->read_flags, 0, sizeof tty->read_flags); | |
1442 | tty->canon_head = tty->read_tail; | |
1443 | tty->canon_data = 0; | |
1444 | tty->erasing = 0; | |
1445 | } | |
1446 | ||
1447 | if (canon_change && !L_ICANON(tty) && tty->read_cnt) | |
1448 | wake_up_interruptible(&tty->read_wait); | |
4edf1827 | 1449 | |
1da177e4 LT |
1450 | tty->icanon = (L_ICANON(tty) != 0); |
1451 | if (test_bit(TTY_HW_COOK_IN, &tty->flags)) { | |
1452 | tty->raw = 1; | |
1453 | tty->real_raw = 1; | |
1454 | return; | |
1455 | } | |
1456 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || | |
1457 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1458 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1459 | I_PARMRK(tty)) { | |
1460 | memset(tty->process_char_map, 0, 256/8); | |
1461 | ||
1462 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1463 | set_bit('\r', tty->process_char_map); | |
1464 | if (I_INLCR(tty)) | |
1465 | set_bit('\n', tty->process_char_map); | |
1466 | ||
1467 | if (L_ICANON(tty)) { | |
1468 | set_bit(ERASE_CHAR(tty), tty->process_char_map); | |
1469 | set_bit(KILL_CHAR(tty), tty->process_char_map); | |
1470 | set_bit(EOF_CHAR(tty), tty->process_char_map); | |
1471 | set_bit('\n', tty->process_char_map); | |
1472 | set_bit(EOL_CHAR(tty), tty->process_char_map); | |
1473 | if (L_IEXTEN(tty)) { | |
1474 | set_bit(WERASE_CHAR(tty), | |
1475 | tty->process_char_map); | |
1476 | set_bit(LNEXT_CHAR(tty), | |
1477 | tty->process_char_map); | |
1478 | set_bit(EOL2_CHAR(tty), | |
1479 | tty->process_char_map); | |
1480 | if (L_ECHO(tty)) | |
1481 | set_bit(REPRINT_CHAR(tty), | |
1482 | tty->process_char_map); | |
1483 | } | |
1484 | } | |
1485 | if (I_IXON(tty)) { | |
1486 | set_bit(START_CHAR(tty), tty->process_char_map); | |
1487 | set_bit(STOP_CHAR(tty), tty->process_char_map); | |
1488 | } | |
1489 | if (L_ISIG(tty)) { | |
1490 | set_bit(INTR_CHAR(tty), tty->process_char_map); | |
1491 | set_bit(QUIT_CHAR(tty), tty->process_char_map); | |
1492 | set_bit(SUSP_CHAR(tty), tty->process_char_map); | |
1493 | } | |
1494 | clear_bit(__DISABLED_CHAR, tty->process_char_map); | |
1495 | tty->raw = 0; | |
1496 | tty->real_raw = 0; | |
1497 | } else { | |
1498 | tty->raw = 1; | |
1499 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && | |
1500 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1501 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
1502 | tty->real_raw = 1; | |
1503 | else | |
1504 | tty->real_raw = 0; | |
1505 | } | |
f34d7a5b AC |
1506 | /* The termios change make the tty ready for I/O */ |
1507 | wake_up_interruptible(&tty->write_wait); | |
1508 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1509 | } |
1510 | ||
1511 | /** | |
1512 | * n_tty_close - close the ldisc for this tty | |
1513 | * @tty: device | |
1514 | * | |
4edf1827 AC |
1515 | * Called from the terminal layer when this line discipline is |
1516 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1517 | * discipline change. The function will not be called while other |
1518 | * ldisc methods are in progress. | |
1519 | */ | |
4edf1827 | 1520 | |
1da177e4 LT |
1521 | static void n_tty_close(struct tty_struct *tty) |
1522 | { | |
1523 | n_tty_flush_buffer(tty); | |
1524 | if (tty->read_buf) { | |
0b4068a1 | 1525 | kfree(tty->read_buf); |
1da177e4 LT |
1526 | tty->read_buf = NULL; |
1527 | } | |
a88a69c9 | 1528 | if (tty->echo_buf) { |
0b4068a1 | 1529 | kfree(tty->echo_buf); |
a88a69c9 JP |
1530 | tty->echo_buf = NULL; |
1531 | } | |
1da177e4 LT |
1532 | } |
1533 | ||
1534 | /** | |
1535 | * n_tty_open - open an ldisc | |
1536 | * @tty: terminal to open | |
1537 | * | |
4edf1827 | 1538 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1539 | * terminal device. Can sleep. Called serialized so that no |
1540 | * other events will occur in parallel. No further open will occur | |
1541 | * until a close. | |
1542 | */ | |
1543 | ||
1544 | static int n_tty_open(struct tty_struct *tty) | |
1545 | { | |
1546 | if (!tty) | |
1547 | return -EINVAL; | |
1548 | ||
a88a69c9 | 1549 | /* These are ugly. Currently a malloc failure here can panic */ |
1da177e4 | 1550 | if (!tty->read_buf) { |
0b4068a1 | 1551 | tty->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1da177e4 LT |
1552 | if (!tty->read_buf) |
1553 | return -ENOMEM; | |
1554 | } | |
a88a69c9 | 1555 | if (!tty->echo_buf) { |
0b4068a1 AC |
1556 | tty->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1557 | ||
a88a69c9 JP |
1558 | if (!tty->echo_buf) |
1559 | return -ENOMEM; | |
1560 | } | |
1da177e4 LT |
1561 | reset_buffer_flags(tty); |
1562 | tty->column = 0; | |
1563 | n_tty_set_termios(tty, NULL); | |
1564 | tty->minimum_to_wake = 1; | |
1565 | tty->closing = 0; | |
1566 | return 0; | |
1567 | } | |
1568 | ||
1569 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1570 | { | |
e043e42b | 1571 | tty_flush_to_ldisc(tty); |
26df6d13 | 1572 | if (tty->icanon && !L_EXTPROC(tty)) { |
1da177e4 LT |
1573 | if (tty->canon_data) |
1574 | return 1; | |
1575 | } else if (tty->read_cnt >= (amt ? amt : 1)) | |
1576 | return 1; | |
1577 | ||
1578 | return 0; | |
1579 | } | |
1580 | ||
1581 | /** | |
1582 | * copy_from_read_buf - copy read data directly | |
1583 | * @tty: terminal device | |
1584 | * @b: user data | |
1585 | * @nr: size of data | |
1586 | * | |
11a96d18 | 1587 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1588 | * ICANON is off; it copies characters straight from the tty queue to |
1589 | * user space directly. It can be profitably called twice; once to | |
1590 | * drain the space from the tail pointer to the (physical) end of the | |
1591 | * buffer, and once to drain the space from the (physical) beginning of | |
1592 | * the buffer to head pointer. | |
1593 | * | |
817d6d3b | 1594 | * Called under the tty->atomic_read_lock sem |
1da177e4 LT |
1595 | * |
1596 | */ | |
4edf1827 | 1597 | |
33f0f88f | 1598 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1599 | unsigned char __user **b, |
1600 | size_t *nr) | |
1601 | ||
1602 | { | |
1603 | int retval; | |
1604 | size_t n; | |
1605 | unsigned long flags; | |
1606 | ||
1607 | retval = 0; | |
1608 | spin_lock_irqsave(&tty->read_lock, flags); | |
1609 | n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail); | |
1610 | n = min(*nr, n); | |
1611 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1612 | if (n) { | |
1da177e4 LT |
1613 | retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n); |
1614 | n -= retval; | |
522ed776 | 1615 | tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n); |
1da177e4 LT |
1616 | spin_lock_irqsave(&tty->read_lock, flags); |
1617 | tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1); | |
1618 | tty->read_cnt -= n; | |
26df6d13 | 1619 | /* Turn single EOF into zero-length read */ |
1620 | if (L_EXTPROC(tty) && tty->icanon && n == 1) { | |
1621 | if (!tty->read_cnt && (*b)[n-1] == EOF_CHAR(tty)) | |
1622 | n--; | |
1623 | } | |
1da177e4 LT |
1624 | spin_unlock_irqrestore(&tty->read_lock, flags); |
1625 | *b += n; | |
1626 | *nr -= n; | |
1627 | } | |
1628 | return retval; | |
1629 | } | |
1630 | ||
cc4191dc | 1631 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1632 | size_t, loff_t *); |
1da177e4 LT |
1633 | |
1634 | /** | |
1635 | * job_control - check job control | |
1636 | * @tty: tty | |
1637 | * @file: file handle | |
1638 | * | |
1639 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1640 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1641 | * error code if action should be taken. |
04f378b1 AC |
1642 | * |
1643 | * FIXME: | |
1644 | * Locking: None - redirected write test is safe, testing | |
1645 | * current->signal should possibly lock current->sighand | |
1646 | * pgrp locking ? | |
1da177e4 | 1647 | */ |
4edf1827 | 1648 | |
1da177e4 LT |
1649 | static int job_control(struct tty_struct *tty, struct file *file) |
1650 | { | |
1651 | /* Job control check -- must be done at start and after | |
1652 | every sleep (POSIX.1 7.1.1.4). */ | |
1653 | /* NOTE: not yet done after every sleep pending a thorough | |
1654 | check of the logic of this change. -- jlc */ | |
1655 | /* don't stop on /dev/console */ | |
1656 | if (file->f_op->write != redirected_tty_write && | |
1657 | current->signal->tty == tty) { | |
ab521dc0 | 1658 | if (!tty->pgrp) |
11a96d18 | 1659 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); |
ab521dc0 | 1660 | else if (task_pgrp(current) != tty->pgrp) { |
1da177e4 | 1661 | if (is_ignored(SIGTTIN) || |
3e7cd6c4 | 1662 | is_current_pgrp_orphaned()) |
1da177e4 | 1663 | return -EIO; |
ab521dc0 | 1664 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); |
040b6362 | 1665 | set_thread_flag(TIF_SIGPENDING); |
1da177e4 LT |
1666 | return -ERESTARTSYS; |
1667 | } | |
1668 | } | |
1669 | return 0; | |
1670 | } | |
4edf1827 | 1671 | |
1da177e4 LT |
1672 | |
1673 | /** | |
11a96d18 | 1674 | * n_tty_read - read function for tty |
1da177e4 LT |
1675 | * @tty: tty device |
1676 | * @file: file object | |
1677 | * @buf: userspace buffer pointer | |
1678 | * @nr: size of I/O | |
1679 | * | |
1680 | * Perform reads for the line discipline. We are guaranteed that the | |
1681 | * line discipline will not be closed under us but we may get multiple | |
1682 | * parallel readers and must handle this ourselves. We may also get | |
1683 | * a hangup. Always called in user context, may sleep. | |
1684 | * | |
1685 | * This code must be sure never to sleep through a hangup. | |
1686 | */ | |
4edf1827 | 1687 | |
11a96d18 | 1688 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1689 | unsigned char __user *buf, size_t nr) |
1690 | { | |
1691 | unsigned char __user *b = buf; | |
1692 | DECLARE_WAITQUEUE(wait, current); | |
1693 | int c; | |
1694 | int minimum, time; | |
1695 | ssize_t retval = 0; | |
1696 | ssize_t size; | |
1697 | long timeout; | |
1698 | unsigned long flags; | |
04f378b1 | 1699 | int packet; |
1da177e4 LT |
1700 | |
1701 | do_it_again: | |
1702 | ||
17b82060 | 1703 | BUG_ON(!tty->read_buf); |
1da177e4 LT |
1704 | |
1705 | c = job_control(tty, file); | |
4edf1827 | 1706 | if (c < 0) |
1da177e4 | 1707 | return c; |
4edf1827 | 1708 | |
1da177e4 LT |
1709 | minimum = time = 0; |
1710 | timeout = MAX_SCHEDULE_TIMEOUT; | |
1711 | if (!tty->icanon) { | |
1712 | time = (HZ / 10) * TIME_CHAR(tty); | |
1713 | minimum = MIN_CHAR(tty); | |
1714 | if (minimum) { | |
1715 | if (time) | |
1716 | tty->minimum_to_wake = 1; | |
1717 | else if (!waitqueue_active(&tty->read_wait) || | |
1718 | (tty->minimum_to_wake > minimum)) | |
1719 | tty->minimum_to_wake = minimum; | |
1720 | } else { | |
1721 | timeout = 0; | |
1722 | if (time) { | |
1723 | timeout = time; | |
1724 | time = 0; | |
1725 | } | |
1726 | tty->minimum_to_wake = minimum = 1; | |
1727 | } | |
1728 | } | |
1729 | ||
1730 | /* | |
1731 | * Internal serialization of reads. | |
1732 | */ | |
1733 | if (file->f_flags & O_NONBLOCK) { | |
70522e12 | 1734 | if (!mutex_trylock(&tty->atomic_read_lock)) |
1da177e4 | 1735 | return -EAGAIN; |
4edf1827 | 1736 | } else { |
70522e12 | 1737 | if (mutex_lock_interruptible(&tty->atomic_read_lock)) |
1da177e4 LT |
1738 | return -ERESTARTSYS; |
1739 | } | |
04f378b1 | 1740 | packet = tty->packet; |
1da177e4 LT |
1741 | |
1742 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
1743 | while (nr) { |
1744 | /* First test for status change. */ | |
04f378b1 | 1745 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
1746 | unsigned char cs; |
1747 | if (b != buf) | |
1748 | break; | |
04f378b1 | 1749 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
1750 | cs = tty->link->ctrl_status; |
1751 | tty->link->ctrl_status = 0; | |
04f378b1 | 1752 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 1753 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
1754 | retval = -EFAULT; |
1755 | b--; | |
1756 | break; | |
1757 | } | |
1758 | nr--; | |
1759 | break; | |
1760 | } | |
1761 | /* This statement must be first before checking for input | |
1762 | so that any interrupt will set the state back to | |
1763 | TASK_RUNNING. */ | |
1764 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 1765 | |
1da177e4 LT |
1766 | if (((minimum - (b - buf)) < tty->minimum_to_wake) && |
1767 | ((minimum - (b - buf)) >= 1)) | |
1768 | tty->minimum_to_wake = (minimum - (b - buf)); | |
4edf1827 | 1769 | |
1da177e4 LT |
1770 | if (!input_available_p(tty, 0)) { |
1771 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
1772 | retval = -EIO; | |
1773 | break; | |
1774 | } | |
1775 | if (tty_hung_up_p(file)) | |
1776 | break; | |
1777 | if (!timeout) | |
1778 | break; | |
1779 | if (file->f_flags & O_NONBLOCK) { | |
1780 | retval = -EAGAIN; | |
1781 | break; | |
1782 | } | |
1783 | if (signal_pending(current)) { | |
1784 | retval = -ERESTARTSYS; | |
1785 | break; | |
1786 | } | |
1da177e4 | 1787 | timeout = schedule_timeout(timeout); |
1da177e4 LT |
1788 | continue; |
1789 | } | |
1790 | __set_current_state(TASK_RUNNING); | |
1791 | ||
1792 | /* Deal with packet mode. */ | |
04f378b1 | 1793 | if (packet && b == buf) { |
522ed776 | 1794 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
1795 | retval = -EFAULT; |
1796 | b--; | |
1797 | break; | |
1798 | } | |
1799 | nr--; | |
1800 | } | |
1801 | ||
26df6d13 | 1802 | if (tty->icanon && !L_EXTPROC(tty)) { |
1da177e4 LT |
1803 | /* N.B. avoid overrun if nr == 0 */ |
1804 | while (nr && tty->read_cnt) { | |
4edf1827 | 1805 | int eol; |
1da177e4 LT |
1806 | |
1807 | eol = test_and_clear_bit(tty->read_tail, | |
1808 | tty->read_flags); | |
1809 | c = tty->read_buf[tty->read_tail]; | |
1810 | spin_lock_irqsave(&tty->read_lock, flags); | |
1811 | tty->read_tail = ((tty->read_tail+1) & | |
1812 | (N_TTY_BUF_SIZE-1)); | |
1813 | tty->read_cnt--; | |
1814 | if (eol) { | |
1815 | /* this test should be redundant: | |
1816 | * we shouldn't be reading data if | |
1817 | * canon_data is 0 | |
1818 | */ | |
1819 | if (--tty->canon_data < 0) | |
1820 | tty->canon_data = 0; | |
1821 | } | |
1822 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1823 | ||
1824 | if (!eol || (c != __DISABLED_CHAR)) { | |
522ed776 | 1825 | if (tty_put_user(tty, c, b++)) { |
1da177e4 LT |
1826 | retval = -EFAULT; |
1827 | b--; | |
1828 | break; | |
1829 | } | |
1830 | nr--; | |
1831 | } | |
522ed776 MT |
1832 | if (eol) { |
1833 | tty_audit_push(tty); | |
1da177e4 | 1834 | break; |
522ed776 | 1835 | } |
1da177e4 LT |
1836 | } |
1837 | if (retval) | |
1838 | break; | |
1839 | } else { | |
1840 | int uncopied; | |
04f378b1 AC |
1841 | /* The copy function takes the read lock and handles |
1842 | locking internally for this case */ | |
1da177e4 LT |
1843 | uncopied = copy_from_read_buf(tty, &b, &nr); |
1844 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
1845 | if (uncopied) { | |
1846 | retval = -EFAULT; | |
1847 | break; | |
1848 | } | |
1849 | } | |
1850 | ||
1851 | /* If there is enough space in the read buffer now, let the | |
1852 | * low-level driver know. We use n_tty_chars_in_buffer() to | |
1853 | * check the buffer, as it now knows about canonical mode. | |
1854 | * Otherwise, if the driver is throttled and the line is | |
1855 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
1856 | * we won't get any more characters. | |
1857 | */ | |
b1c43f82 | 1858 | if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) |
1da177e4 LT |
1859 | check_unthrottle(tty); |
1860 | ||
1861 | if (b - buf >= minimum) | |
1862 | break; | |
1863 | if (time) | |
1864 | timeout = time; | |
1865 | } | |
70522e12 | 1866 | mutex_unlock(&tty->atomic_read_lock); |
1da177e4 LT |
1867 | remove_wait_queue(&tty->read_wait, &wait); |
1868 | ||
1869 | if (!waitqueue_active(&tty->read_wait)) | |
1870 | tty->minimum_to_wake = minimum; | |
1871 | ||
1872 | __set_current_state(TASK_RUNNING); | |
1873 | size = b - buf; | |
1874 | if (size) { | |
1875 | retval = size; | |
1876 | if (nr) | |
4edf1827 | 1877 | clear_bit(TTY_PUSH, &tty->flags); |
1da177e4 LT |
1878 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) |
1879 | goto do_it_again; | |
1880 | ||
1881 | return retval; | |
1882 | } | |
1883 | ||
1884 | /** | |
11a96d18 | 1885 | * n_tty_write - write function for tty |
1da177e4 LT |
1886 | * @tty: tty device |
1887 | * @file: file object | |
1888 | * @buf: userspace buffer pointer | |
1889 | * @nr: size of I/O | |
1890 | * | |
a88a69c9 | 1891 | * Write function of the terminal device. This is serialized with |
1da177e4 | 1892 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
1893 | * and other such events. Since the receive code will echo characters, |
1894 | * thus calling driver write methods, the output_lock is used in | |
1895 | * the output processing functions called here as well as in the | |
1896 | * echo processing function to protect the column state and space | |
1897 | * left in the buffer. | |
1da177e4 LT |
1898 | * |
1899 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
1900 | * |
1901 | * Locking: output_lock to protect column state and space left | |
1902 | * (note that the process_output*() functions take this | |
1903 | * lock themselves) | |
1da177e4 | 1904 | */ |
4edf1827 | 1905 | |
11a96d18 | 1906 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 1907 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
1908 | { |
1909 | const unsigned char *b = buf; | |
1910 | DECLARE_WAITQUEUE(wait, current); | |
1911 | int c; | |
1912 | ssize_t retval = 0; | |
1913 | ||
1914 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
1915 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
1916 | retval = tty_check_change(tty); | |
1917 | if (retval) | |
1918 | return retval; | |
1919 | } | |
1920 | ||
a88a69c9 JP |
1921 | /* Write out any echoed characters that are still pending */ |
1922 | process_echoes(tty); | |
300a6204 | 1923 | |
1da177e4 LT |
1924 | add_wait_queue(&tty->write_wait, &wait); |
1925 | while (1) { | |
1926 | set_current_state(TASK_INTERRUPTIBLE); | |
1927 | if (signal_pending(current)) { | |
1928 | retval = -ERESTARTSYS; | |
1929 | break; | |
1930 | } | |
1931 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
1932 | retval = -EIO; | |
1933 | break; | |
1934 | } | |
1935 | if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
1936 | while (nr > 0) { | |
a88a69c9 | 1937 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
1938 | if (num < 0) { |
1939 | if (num == -EAGAIN) | |
1940 | break; | |
1941 | retval = num; | |
1942 | goto break_out; | |
1943 | } | |
1944 | b += num; | |
1945 | nr -= num; | |
1946 | if (nr == 0) | |
1947 | break; | |
1948 | c = *b; | |
a88a69c9 | 1949 | if (process_output(c, tty) < 0) |
1da177e4 LT |
1950 | break; |
1951 | b++; nr--; | |
1952 | } | |
f34d7a5b AC |
1953 | if (tty->ops->flush_chars) |
1954 | tty->ops->flush_chars(tty); | |
1da177e4 | 1955 | } else { |
d6afe27b | 1956 | while (nr > 0) { |
f34d7a5b | 1957 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
1958 | if (c < 0) { |
1959 | retval = c; | |
1960 | goto break_out; | |
1961 | } | |
1962 | if (!c) | |
1963 | break; | |
1964 | b += c; | |
1965 | nr -= c; | |
1da177e4 | 1966 | } |
1da177e4 LT |
1967 | } |
1968 | if (!nr) | |
1969 | break; | |
1970 | if (file->f_flags & O_NONBLOCK) { | |
1971 | retval = -EAGAIN; | |
1972 | break; | |
1973 | } | |
1974 | schedule(); | |
1975 | } | |
1976 | break_out: | |
1977 | __set_current_state(TASK_RUNNING); | |
1978 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
1979 | if (b - buf != nr && tty->fasync) |
1980 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
1da177e4 LT |
1981 | return (b - buf) ? b - buf : retval; |
1982 | } | |
1983 | ||
1984 | /** | |
11a96d18 | 1985 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
1986 | * @tty: terminal device |
1987 | * @file: file accessing it | |
1988 | * @wait: poll table | |
1989 | * | |
1990 | * Called when the line discipline is asked to poll() for data or | |
1991 | * for special events. This code is not serialized with respect to | |
1992 | * other events save open/close. | |
1993 | * | |
1994 | * This code must be sure never to sleep through a hangup. | |
1995 | * Called without the kernel lock held - fine | |
1da177e4 | 1996 | */ |
4edf1827 | 1997 | |
11a96d18 | 1998 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 1999 | poll_table *wait) |
1da177e4 LT |
2000 | { |
2001 | unsigned int mask = 0; | |
2002 | ||
2003 | poll_wait(file, &tty->read_wait, wait); | |
2004 | poll_wait(file, &tty->write_wait, wait); | |
2005 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2006 | mask |= POLLIN | POLLRDNORM; | |
2007 | if (tty->packet && tty->link->ctrl_status) | |
2008 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2009 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2010 | mask |= POLLHUP; | |
2011 | if (tty_hung_up_p(file)) | |
2012 | mask |= POLLHUP; | |
2013 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2014 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
2015 | tty->minimum_to_wake = MIN_CHAR(tty); | |
2016 | else | |
2017 | tty->minimum_to_wake = 1; | |
2018 | } | |
f34d7a5b AC |
2019 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2020 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2021 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2022 | mask |= POLLOUT | POLLWRNORM; |
2023 | return mask; | |
2024 | } | |
2025 | ||
47afa7a5 AC |
2026 | static unsigned long inq_canon(struct tty_struct *tty) |
2027 | { | |
2028 | int nr, head, tail; | |
2029 | ||
17b82060 | 2030 | if (!tty->canon_data) |
47afa7a5 AC |
2031 | return 0; |
2032 | head = tty->canon_head; | |
2033 | tail = tty->read_tail; | |
2034 | nr = (head - tail) & (N_TTY_BUF_SIZE-1); | |
2035 | /* Skip EOF-chars.. */ | |
2036 | while (head != tail) { | |
2037 | if (test_bit(tail, tty->read_flags) && | |
2038 | tty->read_buf[tail] == __DISABLED_CHAR) | |
2039 | nr--; | |
2040 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
2041 | } | |
2042 | return nr; | |
2043 | } | |
2044 | ||
2045 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2046 | unsigned int cmd, unsigned long arg) | |
2047 | { | |
2048 | int retval; | |
2049 | ||
2050 | switch (cmd) { | |
2051 | case TIOCOUTQ: | |
2052 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2053 | case TIOCINQ: | |
17b82060 | 2054 | /* FIXME: Locking */ |
47afa7a5 AC |
2055 | retval = tty->read_cnt; |
2056 | if (L_ICANON(tty)) | |
2057 | retval = inq_canon(tty); | |
2058 | return put_user(retval, (unsigned int __user *) arg); | |
2059 | default: | |
2060 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2061 | } | |
2062 | } | |
2063 | ||
a352def2 | 2064 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2065 | .magic = TTY_LDISC_MAGIC, |
2066 | .name = "n_tty", | |
2067 | .open = n_tty_open, | |
2068 | .close = n_tty_close, | |
2069 | .flush_buffer = n_tty_flush_buffer, | |
2070 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2071 | .read = n_tty_read, |
2072 | .write = n_tty_write, | |
e10cc1df PF |
2073 | .ioctl = n_tty_ioctl, |
2074 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2075 | .poll = n_tty_poll, |
e10cc1df PF |
2076 | .receive_buf = n_tty_receive_buf, |
2077 | .write_wakeup = n_tty_write_wakeup | |
1da177e4 | 2078 | }; |
572b9adb RG |
2079 | |
2080 | /** | |
2081 | * n_tty_inherit_ops - inherit N_TTY methods | |
2082 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2083 | * | |
2084 | * Used by a generic struct tty_ldisc_ops to easily inherit N_TTY | |
2085 | * methods. | |
2086 | */ | |
2087 | ||
2088 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2089 | { | |
2090 | *ops = tty_ldisc_N_TTY; | |
2091 | ops->owner = NULL; | |
2092 | ops->refcount = ops->flags = 0; | |
2093 | } | |
2094 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |