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