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> | |
1da177e4 LT |
50 | |
51 | #include <asm/uaccess.h> | |
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 | ||
1da177e4 LT |
76 | static inline unsigned char *alloc_buf(void) |
77 | { | |
b4e3ca1a | 78 | gfp_t prio = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL; |
1da177e4 LT |
79 | |
80 | if (PAGE_SIZE != N_TTY_BUF_SIZE) | |
81 | return kmalloc(N_TTY_BUF_SIZE, prio); | |
82 | else | |
83 | return (unsigned char *)__get_free_page(prio); | |
84 | } | |
85 | ||
86 | static inline void free_buf(unsigned char *buf) | |
87 | { | |
88 | if (PAGE_SIZE != N_TTY_BUF_SIZE) | |
89 | kfree(buf); | |
90 | else | |
91 | free_page((unsigned long) buf); | |
92 | } | |
93 | ||
522ed776 MT |
94 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
95 | unsigned char __user *ptr) | |
96 | { | |
97 | tty_audit_add_data(tty, &x, 1); | |
98 | return put_user(x, ptr); | |
99 | } | |
100 | ||
33f0f88f AC |
101 | /** |
102 | * n_tty_set__room - receive space | |
103 | * @tty: terminal | |
104 | * | |
105 | * Called by the driver to find out how much data it is | |
106 | * permitted to feed to the line discipline without any being lost | |
107 | * and thus to manage flow control. Not serialized. Answers for the | |
108 | * "instant". | |
109 | */ | |
110 | ||
111 | static void n_tty_set_room(struct tty_struct *tty) | |
112 | { | |
17b82060 | 113 | /* tty->read_cnt is not read locked ? */ |
33f0f88f AC |
114 | int left = N_TTY_BUF_SIZE - tty->read_cnt - 1; |
115 | ||
116 | /* | |
117 | * If we are doing input canonicalization, and there are no | |
118 | * pending newlines, let characters through without limit, so | |
119 | * that erase characters will be handled. Other excess | |
120 | * characters will be beeped. | |
121 | */ | |
122 | if (left <= 0) | |
123 | left = tty->icanon && !tty->canon_data; | |
124 | tty->receive_room = left; | |
125 | } | |
126 | ||
127 | static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty) | |
1da177e4 LT |
128 | { |
129 | if (tty->read_cnt < N_TTY_BUF_SIZE) { | |
130 | tty->read_buf[tty->read_head] = c; | |
131 | tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1); | |
132 | tty->read_cnt++; | |
133 | } | |
134 | } | |
135 | ||
17b82060 AC |
136 | /** |
137 | * put_tty_queue - add character to tty | |
138 | * @c: character | |
139 | * @tty: tty device | |
140 | * | |
141 | * Add a character to the tty read_buf queue. This is done under the | |
142 | * read_lock to serialize character addition and also to protect us | |
143 | * against parallel reads or flushes | |
144 | */ | |
145 | ||
33f0f88f | 146 | static void put_tty_queue(unsigned char c, struct tty_struct *tty) |
1da177e4 LT |
147 | { |
148 | unsigned long flags; | |
149 | /* | |
150 | * The problem of stomping on the buffers ends here. | |
151 | * Why didn't anyone see this one coming? --AJK | |
152 | */ | |
153 | spin_lock_irqsave(&tty->read_lock, flags); | |
154 | put_tty_queue_nolock(c, tty); | |
155 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
156 | } | |
157 | ||
158 | /** | |
159 | * check_unthrottle - allow new receive data | |
160 | * @tty; tty device | |
161 | * | |
17b82060 AC |
162 | * Check whether to call the driver unthrottle functions |
163 | * | |
70522e12 | 164 | * Can sleep, may be called under the atomic_read_lock mutex but |
1da177e4 LT |
165 | * this is not guaranteed. |
166 | */ | |
4edf1827 | 167 | static void check_unthrottle(struct tty_struct *tty) |
1da177e4 | 168 | { |
39c2e60f AC |
169 | if (tty->count) |
170 | tty_unthrottle(tty); | |
1da177e4 LT |
171 | } |
172 | ||
173 | /** | |
174 | * reset_buffer_flags - reset buffer state | |
175 | * @tty: terminal to reset | |
176 | * | |
4edf1827 | 177 | * Reset the read buffer counters, clear the flags, |
1da177e4 LT |
178 | * and make sure the driver is unthrottled. Called |
179 | * from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 AC |
180 | * |
181 | * Locking: tty_read_lock for read fields. | |
1da177e4 | 182 | */ |
a88a69c9 | 183 | |
1da177e4 LT |
184 | static void reset_buffer_flags(struct tty_struct *tty) |
185 | { | |
186 | unsigned long flags; | |
187 | ||
188 | spin_lock_irqsave(&tty->read_lock, flags); | |
189 | tty->read_head = tty->read_tail = tty->read_cnt = 0; | |
190 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
a88a69c9 JP |
191 | |
192 | mutex_lock(&tty->echo_lock); | |
193 | tty->echo_pos = tty->echo_cnt = tty->echo_overrun = 0; | |
194 | mutex_unlock(&tty->echo_lock); | |
195 | ||
1da177e4 LT |
196 | tty->canon_head = tty->canon_data = tty->erasing = 0; |
197 | memset(&tty->read_flags, 0, sizeof tty->read_flags); | |
33f0f88f | 198 | n_tty_set_room(tty); |
1da177e4 LT |
199 | check_unthrottle(tty); |
200 | } | |
201 | ||
202 | /** | |
203 | * n_tty_flush_buffer - clean input queue | |
204 | * @tty: terminal device | |
205 | * | |
206 | * Flush the input buffer. Called when the line discipline is | |
207 | * being closed, when the tty layer wants the buffer flushed (eg | |
208 | * at hangup) or when the N_TTY line discipline internally has to | |
209 | * clean the pending queue (for example some signals). | |
210 | * | |
17b82060 | 211 | * Locking: ctrl_lock, read_lock. |
1da177e4 | 212 | */ |
4edf1827 AC |
213 | |
214 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 215 | { |
04f378b1 | 216 | unsigned long flags; |
1da177e4 LT |
217 | /* clear everything and unthrottle the driver */ |
218 | reset_buffer_flags(tty); | |
4edf1827 | 219 | |
1da177e4 LT |
220 | if (!tty->link) |
221 | return; | |
222 | ||
04f378b1 | 223 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
1da177e4 LT |
224 | if (tty->link->packet) { |
225 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
226 | wake_up_interruptible(&tty->link->read_wait); | |
227 | } | |
04f378b1 | 228 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1da177e4 LT |
229 | } |
230 | ||
231 | /** | |
232 | * n_tty_chars_in_buffer - report available bytes | |
233 | * @tty: tty device | |
234 | * | |
235 | * Report the number of characters buffered to be delivered to user | |
4edf1827 | 236 | * at this instant in time. |
17b82060 AC |
237 | * |
238 | * Locking: read_lock | |
1da177e4 | 239 | */ |
4edf1827 | 240 | |
1da177e4 LT |
241 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
242 | { | |
243 | unsigned long flags; | |
244 | ssize_t n = 0; | |
245 | ||
246 | spin_lock_irqsave(&tty->read_lock, flags); | |
247 | if (!tty->icanon) { | |
248 | n = tty->read_cnt; | |
249 | } else if (tty->canon_data) { | |
250 | n = (tty->canon_head > tty->read_tail) ? | |
251 | tty->canon_head - tty->read_tail : | |
252 | tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail); | |
253 | } | |
254 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
255 | return n; | |
256 | } | |
257 | ||
258 | /** | |
259 | * is_utf8_continuation - utf8 multibyte check | |
260 | * @c: byte to check | |
261 | * | |
262 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
263 | * character. We use this to correctly compute the on screen size | |
264 | * of the character when printing | |
265 | */ | |
4edf1827 | 266 | |
1da177e4 LT |
267 | static inline int is_utf8_continuation(unsigned char c) |
268 | { | |
269 | return (c & 0xc0) == 0x80; | |
270 | } | |
271 | ||
272 | /** | |
273 | * is_continuation - multibyte check | |
274 | * @c: byte to check | |
275 | * | |
276 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
277 | * character and the terminal is in unicode mode. | |
278 | */ | |
4edf1827 | 279 | |
1da177e4 LT |
280 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
281 | { | |
282 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
283 | } | |
284 | ||
285 | /** | |
a88a69c9 | 286 | * do_output_char - output one character |
1da177e4 LT |
287 | * @c: character (or partial unicode symbol) |
288 | * @tty: terminal device | |
a88a69c9 | 289 | * @space: space available in tty driver write buffer |
1da177e4 | 290 | * |
a88a69c9 JP |
291 | * This is a helper function that handles one output character |
292 | * (including special characters like TAB, CR, LF, etc.), | |
293 | * putting the results in the tty driver's write buffer. | |
294 | * | |
295 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
296 | * and NLDLY. They simply aren't relevant in the world today. | |
297 | * If you ever need them, add them here. | |
1da177e4 | 298 | * |
a88a69c9 JP |
299 | * Returns the number of bytes of buffer space used or -1 if |
300 | * no space left. | |
301 | * | |
302 | * Locking: should be called under the output_lock to protect | |
303 | * the column state and space left in the buffer | |
1da177e4 | 304 | */ |
4edf1827 | 305 | |
a88a69c9 | 306 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 307 | { |
a88a69c9 | 308 | int spaces; |
1da177e4 | 309 | |
1da177e4 LT |
310 | if (!space) |
311 | return -1; | |
a88a69c9 JP |
312 | |
313 | switch (c) { | |
314 | case '\n': | |
315 | if (O_ONLRET(tty)) | |
316 | tty->column = 0; | |
317 | if (O_ONLCR(tty)) { | |
318 | if (space < 2) | |
319 | return -1; | |
1da177e4 | 320 | tty->canon_column = tty->column = 0; |
a88a69c9 JP |
321 | tty_put_char(tty, '\r'); |
322 | tty_put_char(tty, c); | |
323 | return 2; | |
324 | } | |
325 | tty->canon_column = tty->column; | |
326 | break; | |
327 | case '\r': | |
328 | if (O_ONOCR(tty) && tty->column == 0) | |
329 | return 0; | |
330 | if (O_OCRNL(tty)) { | |
331 | c = '\n'; | |
332 | if (O_ONLRET(tty)) | |
333 | tty->canon_column = tty->column = 0; | |
1da177e4 | 334 | break; |
a88a69c9 JP |
335 | } |
336 | tty->canon_column = tty->column = 0; | |
337 | break; | |
338 | case '\t': | |
339 | spaces = 8 - (tty->column & 7); | |
340 | if (O_TABDLY(tty) == XTABS) { | |
341 | if (space < spaces) | |
342 | return -1; | |
1da177e4 | 343 | tty->column += spaces; |
a88a69c9 JP |
344 | tty->ops->write(tty, " ", spaces); |
345 | return spaces; | |
1da177e4 | 346 | } |
a88a69c9 JP |
347 | tty->column += spaces; |
348 | break; | |
349 | case '\b': | |
350 | if (tty->column > 0) | |
351 | tty->column--; | |
352 | break; | |
353 | default: | |
354 | if (O_OLCUC(tty)) | |
355 | c = toupper(c); | |
356 | if (!iscntrl(c) && !is_continuation(c, tty)) | |
357 | tty->column++; | |
358 | break; | |
1da177e4 | 359 | } |
a88a69c9 | 360 | |
f34d7a5b | 361 | tty_put_char(tty, c); |
a88a69c9 JP |
362 | return 1; |
363 | } | |
364 | ||
365 | /** | |
366 | * process_output - output post processor | |
367 | * @c: character (or partial unicode symbol) | |
368 | * @tty: terminal device | |
369 | * | |
370 | * Perform OPOST processing. Returns -1 when the output device is | |
371 | * full and the character must be retried. | |
372 | * | |
373 | * Locking: output_lock to protect column state and space left | |
374 | * (also, this is called from n_tty_write under the | |
375 | * tty layer write lock) | |
376 | */ | |
377 | ||
378 | static int process_output(unsigned char c, struct tty_struct *tty) | |
379 | { | |
380 | int space, retval; | |
381 | ||
382 | mutex_lock(&tty->output_lock); | |
383 | ||
384 | space = tty_write_room(tty); | |
385 | retval = do_output_char(c, tty, space); | |
386 | ||
387 | mutex_unlock(&tty->output_lock); | |
388 | if (retval < 0) | |
389 | return -1; | |
390 | else | |
391 | return 0; | |
1da177e4 LT |
392 | } |
393 | ||
394 | /** | |
a88a69c9 | 395 | * process_output_block - block post processor |
1da177e4 LT |
396 | * @tty: terminal device |
397 | * @inbuf: user buffer | |
398 | * @nr: number of bytes | |
399 | * | |
400 | * This path is used to speed up block console writes, among other | |
401 | * things when processing blocks of output data. It handles only | |
402 | * the simple cases normally found and helps to generate blocks of | |
403 | * symbols for the console driver and thus improve performance. | |
404 | * | |
a88a69c9 JP |
405 | * Locking: output_lock to protect column state and space left |
406 | * (also, this is called from n_tty_write under the | |
407 | * tty layer write lock) | |
1da177e4 | 408 | */ |
4edf1827 | 409 | |
a88a69c9 JP |
410 | static ssize_t process_output_block(struct tty_struct *tty, |
411 | const unsigned char *buf, unsigned int nr) | |
1da177e4 LT |
412 | { |
413 | int space; | |
414 | int i; | |
415 | const unsigned char *cp; | |
416 | ||
a88a69c9 JP |
417 | mutex_lock(&tty->output_lock); |
418 | ||
f34d7a5b | 419 | space = tty_write_room(tty); |
1da177e4 | 420 | if (!space) |
a88a69c9 JP |
421 | { |
422 | mutex_unlock(&tty->output_lock); | |
1da177e4 | 423 | return 0; |
a88a69c9 | 424 | } |
1da177e4 LT |
425 | if (nr > space) |
426 | nr = space; | |
427 | ||
428 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
429 | switch (*cp) { | |
430 | case '\n': | |
431 | if (O_ONLRET(tty)) | |
432 | tty->column = 0; | |
433 | if (O_ONLCR(tty)) | |
434 | goto break_out; | |
435 | tty->canon_column = tty->column; | |
436 | break; | |
437 | case '\r': | |
438 | if (O_ONOCR(tty) && tty->column == 0) | |
439 | goto break_out; | |
440 | if (O_OCRNL(tty)) | |
441 | goto break_out; | |
442 | tty->canon_column = tty->column = 0; | |
443 | break; | |
444 | case '\t': | |
445 | goto break_out; | |
446 | case '\b': | |
447 | if (tty->column > 0) | |
448 | tty->column--; | |
449 | break; | |
450 | default: | |
451 | if (O_OLCUC(tty)) | |
452 | goto break_out; | |
453 | if (!iscntrl(*cp)) | |
454 | tty->column++; | |
455 | break; | |
456 | } | |
457 | } | |
458 | break_out: | |
f34d7a5b | 459 | i = tty->ops->write(tty, buf, i); |
a88a69c9 JP |
460 | |
461 | mutex_unlock(&tty->output_lock); | |
1da177e4 LT |
462 | return i; |
463 | } | |
464 | ||
a88a69c9 JP |
465 | /** |
466 | * process_echoes - write pending echo characters | |
467 | * @tty: terminal device | |
468 | * | |
469 | * Write previously buffered echo (and other ldisc-generated) | |
470 | * characters to the tty. | |
471 | * | |
472 | * Characters generated by the ldisc (including echoes) need to | |
473 | * be buffered because the driver's write buffer can fill during | |
474 | * heavy program output. Echoing straight to the driver will | |
475 | * often fail under these conditions, causing lost characters and | |
476 | * resulting mismatches of ldisc state information. | |
477 | * | |
478 | * Since the ldisc state must represent the characters actually sent | |
479 | * to the driver at the time of the write, operations like certain | |
480 | * changes in column state are also saved in the buffer and executed | |
481 | * here. | |
482 | * | |
483 | * A circular fifo buffer is used so that the most recent characters | |
484 | * are prioritized. Also, when control characters are echoed with a | |
485 | * prefixed "^", the pair is treated atomically and thus not separated. | |
486 | * | |
487 | * Locking: output_lock to protect column state and space left, | |
488 | * echo_lock to protect the echo buffer | |
489 | */ | |
490 | ||
491 | static void process_echoes(struct tty_struct *tty) | |
492 | { | |
493 | int space, nr; | |
494 | unsigned char c; | |
495 | unsigned char *cp, *buf_end; | |
496 | ||
497 | if (!tty->echo_cnt) | |
498 | return; | |
499 | ||
500 | mutex_lock(&tty->output_lock); | |
501 | mutex_lock(&tty->echo_lock); | |
502 | ||
503 | space = tty_write_room(tty); | |
504 | ||
505 | buf_end = tty->echo_buf + N_TTY_BUF_SIZE; | |
506 | cp = tty->echo_buf + tty->echo_pos; | |
507 | nr = tty->echo_cnt; | |
508 | while (nr > 0) { | |
509 | c = *cp; | |
510 | if (c == ECHO_OP_START) { | |
511 | unsigned char op; | |
512 | unsigned char *opp; | |
513 | int no_space_left = 0; | |
514 | ||
515 | /* | |
516 | * If the buffer byte is the start of a multi-byte | |
517 | * operation, get the next byte, which is either the | |
518 | * op code or a control character value. | |
519 | */ | |
520 | opp = cp + 1; | |
521 | if (opp == buf_end) | |
522 | opp -= N_TTY_BUF_SIZE; | |
523 | op = *opp; | |
524 | ||
525 | switch (op) { | |
526 | unsigned int num_chars, num_bs; | |
527 | ||
528 | case ECHO_OP_ERASE_TAB: | |
529 | if (++opp == buf_end) | |
530 | opp -= N_TTY_BUF_SIZE; | |
531 | num_chars = *opp; | |
532 | ||
533 | /* | |
534 | * Determine how many columns to go back | |
535 | * in order to erase the tab. | |
536 | * This depends on the number of columns | |
537 | * used by other characters within the tab | |
538 | * area. If this (modulo 8) count is from | |
539 | * the start of input rather than from a | |
540 | * previous tab, we offset by canon column. | |
541 | * Otherwise, tab spacing is normal. | |
542 | */ | |
543 | if (!(num_chars & 0x80)) | |
544 | num_chars += tty->canon_column; | |
545 | num_bs = 8 - (num_chars & 7); | |
546 | ||
547 | if (num_bs > space) { | |
548 | no_space_left = 1; | |
549 | break; | |
550 | } | |
551 | space -= num_bs; | |
552 | while (num_bs--) { | |
553 | tty_put_char(tty, '\b'); | |
554 | if (tty->column > 0) | |
555 | tty->column--; | |
556 | } | |
557 | cp += 3; | |
558 | nr -= 3; | |
559 | break; | |
560 | ||
561 | case ECHO_OP_SET_CANON_COL: | |
562 | tty->canon_column = tty->column; | |
563 | cp += 2; | |
564 | nr -= 2; | |
565 | break; | |
566 | ||
567 | case ECHO_OP_MOVE_BACK_COL: | |
568 | if (tty->column > 0) | |
569 | tty->column--; | |
570 | cp += 2; | |
571 | nr -= 2; | |
572 | break; | |
573 | ||
574 | case ECHO_OP_START: | |
575 | /* This is an escaped echo op start code */ | |
576 | if (!space) { | |
577 | no_space_left = 1; | |
578 | break; | |
579 | } | |
580 | tty_put_char(tty, ECHO_OP_START); | |
581 | tty->column++; | |
582 | space--; | |
583 | cp += 2; | |
584 | nr -= 2; | |
585 | break; | |
586 | ||
587 | default: | |
588 | if (iscntrl(op)) { | |
589 | if (L_ECHOCTL(tty)) { | |
590 | /* | |
591 | * Ensure there is enough space | |
592 | * for the whole ctrl pair. | |
593 | */ | |
594 | if (space < 2) { | |
595 | no_space_left = 1; | |
596 | break; | |
597 | } | |
598 | tty_put_char(tty, '^'); | |
599 | tty_put_char(tty, op ^ 0100); | |
600 | tty->column += 2; | |
601 | space -= 2; | |
602 | } else { | |
603 | if (!space) { | |
604 | no_space_left = 1; | |
605 | break; | |
606 | } | |
607 | tty_put_char(tty, op); | |
608 | space--; | |
609 | } | |
610 | } | |
611 | /* | |
612 | * If above falls through, this was an | |
613 | * undefined op. | |
614 | */ | |
615 | cp += 2; | |
616 | nr -= 2; | |
617 | } | |
618 | ||
619 | if (no_space_left) | |
620 | break; | |
621 | } else { | |
622 | int retval; | |
623 | ||
624 | if ((retval = do_output_char(c, tty, space)) < 0) | |
625 | break; | |
626 | space -= retval; | |
627 | cp += 1; | |
628 | nr -= 1; | |
629 | } | |
630 | ||
631 | /* When end of circular buffer reached, wrap around */ | |
632 | if (cp >= buf_end) | |
633 | cp -= N_TTY_BUF_SIZE; | |
634 | } | |
635 | ||
636 | if (nr == 0) { | |
637 | tty->echo_pos = 0; | |
638 | tty->echo_cnt = 0; | |
639 | tty->echo_overrun = 0; | |
640 | } else { | |
641 | int num_processed = tty->echo_cnt - nr; | |
642 | tty->echo_pos += num_processed; | |
643 | tty->echo_pos &= N_TTY_BUF_SIZE - 1; | |
644 | tty->echo_cnt = nr; | |
645 | if (num_processed > 0) | |
646 | tty->echo_overrun = 0; | |
647 | } | |
648 | ||
649 | mutex_unlock(&tty->echo_lock); | |
650 | mutex_unlock(&tty->output_lock); | |
651 | ||
652 | if (tty->ops->flush_chars) | |
653 | tty->ops->flush_chars(tty); | |
654 | } | |
655 | ||
656 | /** | |
657 | * add_echo_byte - add a byte to the echo buffer | |
658 | * @c: unicode byte to echo | |
659 | * @tty: terminal device | |
660 | * | |
661 | * Add a character or operation byte to the echo buffer. | |
662 | * | |
663 | * Should be called under the echo lock to protect the echo buffer. | |
664 | */ | |
665 | ||
666 | static void add_echo_byte(unsigned char c, struct tty_struct *tty) | |
667 | { | |
668 | int new_byte_pos; | |
669 | ||
670 | if (tty->echo_cnt == N_TTY_BUF_SIZE) { | |
671 | /* Circular buffer is already at capacity */ | |
672 | new_byte_pos = tty->echo_pos; | |
673 | ||
674 | /* | |
675 | * Since the buffer start position needs to be advanced, | |
676 | * be sure to step by a whole operation byte group. | |
677 | */ | |
678 | if (tty->echo_buf[tty->echo_pos] == ECHO_OP_START) | |
679 | { | |
680 | if (tty->echo_buf[(tty->echo_pos + 1) & | |
681 | (N_TTY_BUF_SIZE - 1)] == | |
682 | ECHO_OP_ERASE_TAB) { | |
683 | tty->echo_pos += 3; | |
684 | tty->echo_cnt -= 2; | |
685 | } else { | |
686 | tty->echo_pos += 2; | |
687 | tty->echo_cnt -= 1; | |
688 | } | |
689 | } else { | |
690 | tty->echo_pos++; | |
691 | } | |
692 | tty->echo_pos &= N_TTY_BUF_SIZE - 1; | |
693 | ||
694 | tty->echo_overrun = 1; | |
695 | } else { | |
696 | new_byte_pos = tty->echo_pos + tty->echo_cnt; | |
697 | new_byte_pos &= N_TTY_BUF_SIZE - 1; | |
698 | tty->echo_cnt++; | |
699 | } | |
700 | ||
701 | tty->echo_buf[new_byte_pos] = c; | |
702 | } | |
703 | ||
704 | /** | |
705 | * echo_move_back_col - add operation to move back a column | |
706 | * @tty: terminal device | |
707 | * | |
708 | * Add an operation to the echo buffer to move back one column. | |
709 | * | |
710 | * Locking: echo_lock to protect the echo buffer | |
711 | */ | |
712 | ||
713 | static void echo_move_back_col(struct tty_struct *tty) | |
714 | { | |
715 | mutex_lock(&tty->echo_lock); | |
716 | ||
717 | add_echo_byte(ECHO_OP_START, tty); | |
718 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty); | |
719 | ||
720 | mutex_unlock(&tty->echo_lock); | |
721 | } | |
722 | ||
723 | /** | |
724 | * echo_set_canon_col - add operation to set the canon column | |
725 | * @tty: terminal device | |
726 | * | |
727 | * Add an operation to the echo buffer to set the canon column | |
728 | * to the current column. | |
729 | * | |
730 | * Locking: echo_lock to protect the echo buffer | |
731 | */ | |
732 | ||
733 | static void echo_set_canon_col(struct tty_struct *tty) | |
734 | { | |
735 | mutex_lock(&tty->echo_lock); | |
736 | ||
737 | add_echo_byte(ECHO_OP_START, tty); | |
738 | add_echo_byte(ECHO_OP_SET_CANON_COL, tty); | |
739 | ||
740 | mutex_unlock(&tty->echo_lock); | |
741 | } | |
742 | ||
743 | /** | |
744 | * echo_erase_tab - add operation to erase a tab | |
745 | * @num_chars: number of character columns already used | |
746 | * @after_tab: true if num_chars starts after a previous tab | |
747 | * @tty: terminal device | |
748 | * | |
749 | * Add an operation to the echo buffer to erase a tab. | |
750 | * | |
751 | * Called by the eraser function, which knows how many character | |
752 | * columns have been used since either a previous tab or the start | |
753 | * of input. This information will be used later, along with | |
754 | * canon column (if applicable), to go back the correct number | |
755 | * of columns. | |
756 | * | |
757 | * Locking: echo_lock to protect the echo buffer | |
758 | */ | |
759 | ||
760 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
761 | struct tty_struct *tty) | |
762 | { | |
763 | mutex_lock(&tty->echo_lock); | |
764 | ||
765 | add_echo_byte(ECHO_OP_START, tty); | |
766 | add_echo_byte(ECHO_OP_ERASE_TAB, tty); | |
767 | ||
768 | /* We only need to know this modulo 8 (tab spacing) */ | |
769 | num_chars &= 7; | |
770 | ||
771 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
772 | if (after_tab) | |
773 | num_chars |= 0x80; | |
774 | ||
775 | add_echo_byte(num_chars, tty); | |
776 | ||
777 | mutex_unlock(&tty->echo_lock); | |
778 | } | |
779 | ||
780 | /** | |
781 | * echo_char_raw - echo a character raw | |
782 | * @c: unicode byte to echo | |
783 | * @tty: terminal device | |
784 | * | |
785 | * Echo user input back onto the screen. This must be called only when | |
786 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
787 | * | |
788 | * This variant does not treat control characters specially. | |
789 | * | |
790 | * Locking: echo_lock to protect the echo buffer | |
791 | */ | |
792 | ||
793 | static void echo_char_raw(unsigned char c, struct tty_struct *tty) | |
794 | { | |
795 | mutex_lock(&tty->echo_lock); | |
796 | ||
797 | if (c == ECHO_OP_START) { | |
798 | add_echo_byte(ECHO_OP_START, tty); | |
799 | add_echo_byte(ECHO_OP_START, tty); | |
800 | } else { | |
801 | add_echo_byte(c, tty); | |
802 | } | |
803 | ||
804 | mutex_unlock(&tty->echo_lock); | |
805 | } | |
1da177e4 | 806 | |
1da177e4 | 807 | /** |
a88a69c9 | 808 | * echo_char - echo a character |
1da177e4 LT |
809 | * @c: unicode byte to echo |
810 | * @tty: terminal device | |
811 | * | |
4edf1827 | 812 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 813 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 814 | * |
a88a69c9 JP |
815 | * This variant tags control characters to be possibly echoed as |
816 | * as "^X" (where X is the letter representing the control char). | |
817 | * | |
818 | * Locking: echo_lock to protect the echo buffer | |
1da177e4 LT |
819 | */ |
820 | ||
821 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
822 | { | |
a88a69c9 JP |
823 | mutex_lock(&tty->echo_lock); |
824 | ||
825 | if (c == ECHO_OP_START) { | |
826 | add_echo_byte(ECHO_OP_START, tty); | |
827 | add_echo_byte(ECHO_OP_START, tty); | |
828 | } else { | |
829 | if (iscntrl(c) && c != '\t') | |
830 | add_echo_byte(ECHO_OP_START, tty); | |
831 | add_echo_byte(c, tty); | |
832 | } | |
833 | ||
834 | mutex_unlock(&tty->echo_lock); | |
1da177e4 LT |
835 | } |
836 | ||
17b82060 | 837 | /** |
a88a69c9 | 838 | * finish_erasing - complete erase |
17b82060 | 839 | * @tty: tty doing the erase |
17b82060 | 840 | */ |
a88a69c9 | 841 | |
1da177e4 LT |
842 | static inline void finish_erasing(struct tty_struct *tty) |
843 | { | |
844 | if (tty->erasing) { | |
a88a69c9 | 845 | echo_char_raw('/', tty); |
1da177e4 LT |
846 | tty->erasing = 0; |
847 | } | |
848 | } | |
849 | ||
850 | /** | |
851 | * eraser - handle erase function | |
852 | * @c: character input | |
853 | * @tty: terminal device | |
854 | * | |
3a4fa0a2 | 855 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
856 | * present in the stream from the driver layer. Handles the complexities |
857 | * of UTF-8 multibyte symbols. | |
17b82060 | 858 | * |
a88a69c9 | 859 | * Locking: read_lock for tty buffers |
1da177e4 | 860 | */ |
4edf1827 | 861 | |
1da177e4 LT |
862 | static void eraser(unsigned char c, struct tty_struct *tty) |
863 | { | |
864 | enum { ERASE, WERASE, KILL } kill_type; | |
865 | int head, seen_alnums, cnt; | |
866 | unsigned long flags; | |
867 | ||
17b82060 | 868 | /* FIXME: locking needed ? */ |
1da177e4 | 869 | if (tty->read_head == tty->canon_head) { |
a88a69c9 | 870 | /* echo_char_raw('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
871 | return; |
872 | } | |
873 | if (c == ERASE_CHAR(tty)) | |
874 | kill_type = ERASE; | |
875 | else if (c == WERASE_CHAR(tty)) | |
876 | kill_type = WERASE; | |
877 | else { | |
878 | if (!L_ECHO(tty)) { | |
879 | spin_lock_irqsave(&tty->read_lock, flags); | |
880 | tty->read_cnt -= ((tty->read_head - tty->canon_head) & | |
881 | (N_TTY_BUF_SIZE - 1)); | |
882 | tty->read_head = tty->canon_head; | |
883 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
884 | return; | |
885 | } | |
886 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
887 | spin_lock_irqsave(&tty->read_lock, flags); | |
888 | tty->read_cnt -= ((tty->read_head - tty->canon_head) & | |
889 | (N_TTY_BUF_SIZE - 1)); | |
890 | tty->read_head = tty->canon_head; | |
891 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
892 | finish_erasing(tty); | |
893 | echo_char(KILL_CHAR(tty), tty); | |
894 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
895 | if (L_ECHOK(tty)) | |
a88a69c9 | 896 | echo_char_raw('\n', tty); |
1da177e4 LT |
897 | return; |
898 | } | |
899 | kill_type = KILL; | |
900 | } | |
901 | ||
902 | seen_alnums = 0; | |
17b82060 | 903 | /* FIXME: Locking ?? */ |
1da177e4 LT |
904 | while (tty->read_head != tty->canon_head) { |
905 | head = tty->read_head; | |
906 | ||
907 | /* erase a single possibly multibyte character */ | |
908 | do { | |
909 | head = (head - 1) & (N_TTY_BUF_SIZE-1); | |
910 | c = tty->read_buf[head]; | |
911 | } while (is_continuation(c, tty) && head != tty->canon_head); | |
912 | ||
913 | /* do not partially erase */ | |
914 | if (is_continuation(c, tty)) | |
915 | break; | |
916 | ||
917 | if (kill_type == WERASE) { | |
918 | /* Equivalent to BSD's ALTWERASE. */ | |
919 | if (isalnum(c) || c == '_') | |
920 | seen_alnums++; | |
921 | else if (seen_alnums) | |
922 | break; | |
923 | } | |
924 | cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1); | |
925 | spin_lock_irqsave(&tty->read_lock, flags); | |
926 | tty->read_head = head; | |
927 | tty->read_cnt -= cnt; | |
928 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
929 | if (L_ECHO(tty)) { | |
930 | if (L_ECHOPRT(tty)) { | |
931 | if (!tty->erasing) { | |
a88a69c9 | 932 | echo_char_raw('\\', tty); |
1da177e4 LT |
933 | tty->erasing = 1; |
934 | } | |
935 | /* if cnt > 1, output a multi-byte character */ | |
936 | echo_char(c, tty); | |
937 | while (--cnt > 0) { | |
938 | head = (head+1) & (N_TTY_BUF_SIZE-1); | |
a88a69c9 JP |
939 | echo_char_raw(tty->read_buf[head], tty); |
940 | echo_move_back_col(tty); | |
1da177e4 LT |
941 | } |
942 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
943 | echo_char(ERASE_CHAR(tty), tty); | |
944 | } else if (c == '\t') { | |
a88a69c9 JP |
945 | unsigned int num_chars = 0; |
946 | int after_tab = 0; | |
947 | unsigned long tail = tty->read_head; | |
948 | ||
949 | /* | |
950 | * Count the columns used for characters | |
951 | * since the start of input or after a | |
952 | * previous tab. | |
953 | * This info is used to go back the correct | |
954 | * number of columns. | |
955 | */ | |
956 | while (tail != tty->canon_head) { | |
957 | tail = (tail-1) & (N_TTY_BUF_SIZE-1); | |
1da177e4 | 958 | c = tty->read_buf[tail]; |
a88a69c9 JP |
959 | if (c == '\t') { |
960 | after_tab = 1; | |
961 | break; | |
962 | } | |
1da177e4 LT |
963 | else if (iscntrl(c)) { |
964 | if (L_ECHOCTL(tty)) | |
a88a69c9 JP |
965 | num_chars += 2; |
966 | } else if (!is_continuation(c, tty)) { | |
967 | num_chars++; | |
968 | } | |
1da177e4 | 969 | } |
a88a69c9 | 970 | echo_erase_tab(num_chars, after_tab, tty); |
1da177e4 LT |
971 | } else { |
972 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
a88a69c9 JP |
973 | echo_char_raw('\b', tty); |
974 | echo_char_raw(' ', tty); | |
975 | echo_char_raw('\b', tty); | |
1da177e4 LT |
976 | } |
977 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
a88a69c9 JP |
978 | echo_char_raw('\b', tty); |
979 | echo_char_raw(' ', tty); | |
980 | echo_char_raw('\b', tty); | |
1da177e4 LT |
981 | } |
982 | } | |
983 | } | |
984 | if (kill_type == ERASE) | |
985 | break; | |
986 | } | |
a88a69c9 | 987 | if (tty->read_head == tty->canon_head && L_ECHO(tty)) |
1da177e4 LT |
988 | finish_erasing(tty); |
989 | } | |
990 | ||
991 | /** | |
992 | * isig - handle the ISIG optio | |
993 | * @sig: signal | |
994 | * @tty: terminal | |
995 | * @flush: force flush | |
996 | * | |
997 | * Called when a signal is being sent due to terminal input. This | |
998 | * may caus terminal flushing to take place according to the termios | |
999 | * settings and character used. Called from the driver receive_buf | |
1000 | * path so serialized. | |
17b82060 AC |
1001 | * |
1002 | * Locking: ctrl_lock, read_lock (both via flush buffer) | |
1da177e4 | 1003 | */ |
4edf1827 | 1004 | |
1da177e4 LT |
1005 | static inline void isig(int sig, struct tty_struct *tty, int flush) |
1006 | { | |
ab521dc0 EB |
1007 | if (tty->pgrp) |
1008 | kill_pgrp(tty->pgrp, sig, 1); | |
1da177e4 LT |
1009 | if (flush || !L_NOFLSH(tty)) { |
1010 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1011 | tty_driver_flush_buffer(tty); |
1da177e4 LT |
1012 | } |
1013 | } | |
1014 | ||
1015 | /** | |
1016 | * n_tty_receive_break - handle break | |
1017 | * @tty: terminal | |
1018 | * | |
1019 | * An RS232 break event has been hit in the incoming bitstream. This | |
1020 | * can cause a variety of events depending upon the termios settings. | |
1021 | * | |
1022 | * Called from the receive_buf path so single threaded. | |
1023 | */ | |
4edf1827 | 1024 | |
1da177e4 LT |
1025 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1026 | { | |
1027 | if (I_IGNBRK(tty)) | |
1028 | return; | |
1029 | if (I_BRKINT(tty)) { | |
1030 | isig(SIGINT, tty, 1); | |
1031 | return; | |
1032 | } | |
1033 | if (I_PARMRK(tty)) { | |
1034 | put_tty_queue('\377', tty); | |
1035 | put_tty_queue('\0', tty); | |
1036 | } | |
1037 | put_tty_queue('\0', tty); | |
1038 | wake_up_interruptible(&tty->read_wait); | |
1039 | } | |
1040 | ||
1041 | /** | |
1042 | * n_tty_receive_overrun - handle overrun reporting | |
1043 | * @tty: terminal | |
1044 | * | |
1045 | * Data arrived faster than we could process it. While the tty | |
1046 | * driver has flagged this the bits that were missed are gone | |
1047 | * forever. | |
1048 | * | |
1049 | * Called from the receive_buf path so single threaded. Does not | |
1050 | * need locking as num_overrun and overrun_time are function | |
1051 | * private. | |
1052 | */ | |
4edf1827 | 1053 | |
1da177e4 LT |
1054 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1055 | { | |
1056 | char buf[64]; | |
1057 | ||
1058 | tty->num_overrun++; | |
1059 | if (time_before(tty->overrun_time, jiffies - HZ) || | |
1060 | time_after(tty->overrun_time, jiffies)) { | |
1061 | printk(KERN_WARNING "%s: %d input overrun(s)\n", | |
1062 | tty_name(tty, buf), | |
1063 | tty->num_overrun); | |
1064 | tty->overrun_time = jiffies; | |
1065 | tty->num_overrun = 0; | |
1066 | } | |
1067 | } | |
1068 | ||
1069 | /** | |
1070 | * n_tty_receive_parity_error - error notifier | |
1071 | * @tty: terminal device | |
1072 | * @c: character | |
1073 | * | |
1074 | * Process a parity error and queue the right data to indicate | |
3a4fa0a2 | 1075 | * the error case if necessary. Locking as per n_tty_receive_buf. |
1da177e4 LT |
1076 | */ |
1077 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1078 | unsigned char c) | |
1079 | { | |
4edf1827 | 1080 | if (I_IGNPAR(tty)) |
1da177e4 | 1081 | return; |
1da177e4 LT |
1082 | if (I_PARMRK(tty)) { |
1083 | put_tty_queue('\377', tty); | |
1084 | put_tty_queue('\0', tty); | |
1085 | put_tty_queue(c, tty); | |
1086 | } else if (I_INPCK(tty)) | |
1087 | put_tty_queue('\0', tty); | |
1088 | else | |
1089 | put_tty_queue(c, tty); | |
1090 | wake_up_interruptible(&tty->read_wait); | |
1091 | } | |
1092 | ||
1093 | /** | |
1094 | * n_tty_receive_char - perform processing | |
1095 | * @tty: terminal device | |
1096 | * @c: character | |
1097 | * | |
1098 | * Process an individual character of input received from the driver. | |
4edf1827 | 1099 | * This is serialized with respect to itself by the rules for the |
1da177e4 LT |
1100 | * driver above. |
1101 | */ | |
1102 | ||
1103 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1104 | { | |
1105 | unsigned long flags; | |
1106 | ||
1107 | if (tty->raw) { | |
1108 | put_tty_queue(c, tty); | |
1109 | return; | |
1110 | } | |
4edf1827 | 1111 | |
1da177e4 LT |
1112 | if (I_ISTRIP(tty)) |
1113 | c &= 0x7f; | |
1114 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1115 | c=tolower(c); | |
1116 | ||
54d2a37e | 1117 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1118 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1119 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1120 | start_tty(tty); |
a88a69c9 JP |
1121 | process_echoes(tty); |
1122 | } | |
54d2a37e | 1123 | |
1da177e4 LT |
1124 | if (tty->closing) { |
1125 | if (I_IXON(tty)) { | |
a88a69c9 | 1126 | if (c == START_CHAR(tty)) { |
1da177e4 | 1127 | start_tty(tty); |
a88a69c9 JP |
1128 | process_echoes(tty); |
1129 | } | |
1da177e4 LT |
1130 | else if (c == STOP_CHAR(tty)) |
1131 | stop_tty(tty); | |
1132 | } | |
1133 | return; | |
1134 | } | |
1135 | ||
1136 | /* | |
1137 | * If the previous character was LNEXT, or we know that this | |
1138 | * character is not one of the characters that we'll have to | |
1139 | * handle specially, do shortcut processing to speed things | |
1140 | * up. | |
1141 | */ | |
1142 | if (!test_bit(c, tty->process_char_map) || tty->lnext) { | |
1da177e4 LT |
1143 | tty->lnext = 0; |
1144 | if (L_ECHO(tty)) { | |
a88a69c9 | 1145 | finish_erasing(tty); |
1da177e4 | 1146 | if (tty->read_cnt >= N_TTY_BUF_SIZE-1) { |
a88a69c9 JP |
1147 | /* beep if no space */ |
1148 | echo_char_raw('\a', tty); | |
1149 | process_echoes(tty); | |
1da177e4 LT |
1150 | return; |
1151 | } | |
1152 | /* Record the column of first canon char. */ | |
1153 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1154 | echo_set_canon_col(tty); |
1da177e4 | 1155 | echo_char(c, tty); |
a88a69c9 | 1156 | process_echoes(tty); |
1da177e4 LT |
1157 | } |
1158 | if (I_PARMRK(tty) && c == (unsigned char) '\377') | |
1159 | put_tty_queue(c, tty); | |
1160 | put_tty_queue(c, tty); | |
1161 | return; | |
1162 | } | |
4edf1827 | 1163 | |
1da177e4 LT |
1164 | if (I_IXON(tty)) { |
1165 | if (c == START_CHAR(tty)) { | |
1166 | start_tty(tty); | |
a88a69c9 | 1167 | process_echoes(tty); |
1da177e4 LT |
1168 | return; |
1169 | } | |
1170 | if (c == STOP_CHAR(tty)) { | |
1171 | stop_tty(tty); | |
1172 | return; | |
1173 | } | |
1174 | } | |
575537b3 | 1175 | |
1da177e4 LT |
1176 | if (L_ISIG(tty)) { |
1177 | int signal; | |
1178 | signal = SIGINT; | |
1179 | if (c == INTR_CHAR(tty)) | |
1180 | goto send_signal; | |
1181 | signal = SIGQUIT; | |
1182 | if (c == QUIT_CHAR(tty)) | |
1183 | goto send_signal; | |
1184 | signal = SIGTSTP; | |
1185 | if (c == SUSP_CHAR(tty)) { | |
1186 | send_signal: | |
ec5b1157 | 1187 | /* |
ec5b1157 JP |
1188 | * Note that we do not use isig() here because we want |
1189 | * the order to be: | |
1190 | * 1) flush, 2) echo, 3) signal | |
1191 | */ | |
1192 | if (!L_NOFLSH(tty)) { | |
1193 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1194 | tty_driver_flush_buffer(tty); |
ec5b1157 | 1195 | } |
a88a69c9 JP |
1196 | if (I_IXON(tty)) |
1197 | start_tty(tty); | |
1198 | if (L_ECHO(tty)) { | |
ec5b1157 | 1199 | echo_char(c, tty); |
a88a69c9 JP |
1200 | process_echoes(tty); |
1201 | } | |
ec5b1157 JP |
1202 | if (tty->pgrp) |
1203 | kill_pgrp(tty->pgrp, signal, 1); | |
1da177e4 LT |
1204 | return; |
1205 | } | |
1206 | } | |
575537b3 JP |
1207 | |
1208 | if (c == '\r') { | |
1209 | if (I_IGNCR(tty)) | |
1210 | return; | |
1211 | if (I_ICRNL(tty)) | |
1212 | c = '\n'; | |
1213 | } else if (c == '\n' && I_INLCR(tty)) | |
1214 | c = '\r'; | |
1215 | ||
1da177e4 LT |
1216 | if (tty->icanon) { |
1217 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || | |
1218 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1219 | eraser(c, tty); | |
a88a69c9 | 1220 | process_echoes(tty); |
1da177e4 LT |
1221 | return; |
1222 | } | |
1223 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
1224 | tty->lnext = 1; | |
1225 | if (L_ECHO(tty)) { | |
1226 | finish_erasing(tty); | |
1227 | if (L_ECHOCTL(tty)) { | |
a88a69c9 JP |
1228 | echo_char_raw('^', tty); |
1229 | echo_char_raw('\b', tty); | |
1230 | process_echoes(tty); | |
1da177e4 LT |
1231 | } |
1232 | } | |
1233 | return; | |
1234 | } | |
1235 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1236 | L_IEXTEN(tty)) { | |
1237 | unsigned long tail = tty->canon_head; | |
1238 | ||
1239 | finish_erasing(tty); | |
1240 | echo_char(c, tty); | |
a88a69c9 | 1241 | echo_char_raw('\n', tty); |
1da177e4 LT |
1242 | while (tail != tty->read_head) { |
1243 | echo_char(tty->read_buf[tail], tty); | |
1244 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
1245 | } | |
a88a69c9 | 1246 | process_echoes(tty); |
1da177e4 LT |
1247 | return; |
1248 | } | |
1249 | if (c == '\n') { | |
1250 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
d6afe27b | 1251 | if (tty->read_cnt >= N_TTY_BUF_SIZE-1) |
a88a69c9 JP |
1252 | echo_char_raw('\a', tty); |
1253 | echo_char_raw('\n', tty); | |
1254 | process_echoes(tty); | |
1da177e4 LT |
1255 | } |
1256 | goto handle_newline; | |
1257 | } | |
1258 | if (c == EOF_CHAR(tty)) { | |
4edf1827 AC |
1259 | if (tty->canon_head != tty->read_head) |
1260 | set_bit(TTY_PUSH, &tty->flags); | |
1da177e4 LT |
1261 | c = __DISABLED_CHAR; |
1262 | goto handle_newline; | |
1263 | } | |
1264 | if ((c == EOL_CHAR(tty)) || | |
1265 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1266 | /* | |
1267 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1268 | */ | |
1269 | if (L_ECHO(tty)) { | |
d6afe27b | 1270 | if (tty->read_cnt >= N_TTY_BUF_SIZE-1) |
a88a69c9 | 1271 | echo_char_raw('\a', tty); |
1da177e4 LT |
1272 | /* Record the column of first canon char. */ |
1273 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1274 | echo_set_canon_col(tty); |
1da177e4 | 1275 | echo_char(c, tty); |
a88a69c9 | 1276 | process_echoes(tty); |
1da177e4 LT |
1277 | } |
1278 | /* | |
1279 | * XXX does PARMRK doubling happen for | |
1280 | * EOL_CHAR and EOL2_CHAR? | |
1281 | */ | |
1282 | if (I_PARMRK(tty) && c == (unsigned char) '\377') | |
1283 | put_tty_queue(c, tty); | |
1284 | ||
4edf1827 | 1285 | handle_newline: |
1da177e4 LT |
1286 | spin_lock_irqsave(&tty->read_lock, flags); |
1287 | set_bit(tty->read_head, tty->read_flags); | |
1288 | put_tty_queue_nolock(c, tty); | |
1289 | tty->canon_head = tty->read_head; | |
1290 | tty->canon_data++; | |
1291 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1292 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); | |
1293 | if (waitqueue_active(&tty->read_wait)) | |
1294 | wake_up_interruptible(&tty->read_wait); | |
1295 | return; | |
1296 | } | |
1297 | } | |
4edf1827 | 1298 | |
1da177e4 | 1299 | if (L_ECHO(tty)) { |
a88a69c9 | 1300 | finish_erasing(tty); |
1da177e4 | 1301 | if (tty->read_cnt >= N_TTY_BUF_SIZE-1) { |
a88a69c9 JP |
1302 | /* beep if no space */ |
1303 | echo_char_raw('\a', tty); | |
1304 | process_echoes(tty); | |
1da177e4 LT |
1305 | return; |
1306 | } | |
1307 | if (c == '\n') | |
a88a69c9 | 1308 | echo_char_raw('\n', tty); |
1da177e4 LT |
1309 | else { |
1310 | /* Record the column of first canon char. */ | |
1311 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1312 | echo_set_canon_col(tty); |
1da177e4 LT |
1313 | echo_char(c, tty); |
1314 | } | |
a88a69c9 | 1315 | process_echoes(tty); |
1da177e4 LT |
1316 | } |
1317 | ||
1318 | if (I_PARMRK(tty) && c == (unsigned char) '\377') | |
1319 | put_tty_queue(c, tty); | |
1320 | ||
1321 | put_tty_queue(c, tty); | |
4edf1827 | 1322 | } |
1da177e4 | 1323 | |
1da177e4 LT |
1324 | |
1325 | /** | |
1326 | * n_tty_write_wakeup - asynchronous I/O notifier | |
1327 | * @tty: tty device | |
1328 | * | |
1329 | * Required for the ptys, serial driver etc. since processes | |
1330 | * that attach themselves to the master and rely on ASYNC | |
1331 | * IO must be woken up | |
1332 | */ | |
1333 | ||
1334 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
1335 | { | |
a88a69c9 JP |
1336 | /* Write out any echoed characters that are still pending */ |
1337 | process_echoes(tty); | |
1338 | ||
4edf1827 AC |
1339 | if (tty->fasync) { |
1340 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
1da177e4 LT |
1341 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); |
1342 | } | |
1da177e4 LT |
1343 | } |
1344 | ||
1345 | /** | |
1346 | * n_tty_receive_buf - data receive | |
1347 | * @tty: terminal device | |
1348 | * @cp: buffer | |
1349 | * @fp: flag buffer | |
1350 | * @count: characters | |
1351 | * | |
1352 | * Called by the terminal driver when a block of characters has | |
1353 | * been received. This function must be called from soft contexts | |
1354 | * not from interrupt context. The driver is responsible for making | |
1355 | * calls one at a time and in order (or using flush_to_ldisc) | |
1356 | */ | |
4edf1827 | 1357 | |
1da177e4 LT |
1358 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1359 | char *fp, int count) | |
1360 | { | |
1361 | const unsigned char *p; | |
1362 | char *f, flags = TTY_NORMAL; | |
1363 | int i; | |
1364 | char buf[64]; | |
1365 | unsigned long cpuflags; | |
1366 | ||
1367 | if (!tty->read_buf) | |
1368 | return; | |
1369 | ||
1370 | if (tty->real_raw) { | |
1371 | spin_lock_irqsave(&tty->read_lock, cpuflags); | |
1372 | i = min(N_TTY_BUF_SIZE - tty->read_cnt, | |
1373 | N_TTY_BUF_SIZE - tty->read_head); | |
1374 | i = min(count, i); | |
1375 | memcpy(tty->read_buf + tty->read_head, cp, i); | |
1376 | tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1377 | tty->read_cnt += i; | |
1378 | cp += i; | |
1379 | count -= i; | |
1380 | ||
1381 | i = min(N_TTY_BUF_SIZE - tty->read_cnt, | |
1382 | N_TTY_BUF_SIZE - tty->read_head); | |
1383 | i = min(count, i); | |
1384 | memcpy(tty->read_buf + tty->read_head, cp, i); | |
1385 | tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1386 | tty->read_cnt += i; | |
1387 | spin_unlock_irqrestore(&tty->read_lock, cpuflags); | |
1388 | } else { | |
4edf1827 | 1389 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1390 | if (f) |
1391 | flags = *f++; | |
1392 | switch (flags) { | |
1393 | case TTY_NORMAL: | |
1394 | n_tty_receive_char(tty, *p); | |
1395 | break; | |
1396 | case TTY_BREAK: | |
1397 | n_tty_receive_break(tty); | |
1398 | break; | |
1399 | case TTY_PARITY: | |
1400 | case TTY_FRAME: | |
1401 | n_tty_receive_parity_error(tty, *p); | |
1402 | break; | |
1403 | case TTY_OVERRUN: | |
1404 | n_tty_receive_overrun(tty); | |
1405 | break; | |
1406 | default: | |
4edf1827 | 1407 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1408 | tty_name(tty, buf), flags); |
1409 | break; | |
1410 | } | |
1411 | } | |
f34d7a5b AC |
1412 | if (tty->ops->flush_chars) |
1413 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1414 | } |
1415 | ||
33f0f88f AC |
1416 | n_tty_set_room(tty); |
1417 | ||
1da177e4 LT |
1418 | if (!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) { |
1419 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); | |
1420 | if (waitqueue_active(&tty->read_wait)) | |
1421 | wake_up_interruptible(&tty->read_wait); | |
1422 | } | |
1423 | ||
1424 | /* | |
1425 | * Check the remaining room for the input canonicalization | |
1426 | * mode. We don't want to throttle the driver if we're in | |
1427 | * canonical mode and don't have a newline yet! | |
1428 | */ | |
39c2e60f AC |
1429 | if (tty->receive_room < TTY_THRESHOLD_THROTTLE) |
1430 | tty_throttle(tty); | |
1da177e4 LT |
1431 | } |
1432 | ||
1433 | int is_ignored(int sig) | |
1434 | { | |
1435 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1436 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1437 | } |
1438 | ||
1439 | /** | |
1440 | * n_tty_set_termios - termios data changed | |
1441 | * @tty: terminal | |
1442 | * @old: previous data | |
1443 | * | |
1444 | * Called by the tty layer when the user changes termios flags so | |
1445 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1446 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1447 | * guaranteed that this function will not be re-entered or in progress |
1448 | * when the ldisc is closed. | |
17b82060 AC |
1449 | * |
1450 | * Locking: Caller holds tty->termios_mutex | |
1da177e4 | 1451 | */ |
4edf1827 AC |
1452 | |
1453 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1454 | { |
47afa7a5 AC |
1455 | int canon_change = 1; |
1456 | BUG_ON(!tty); | |
1457 | ||
1458 | if (old) | |
1459 | canon_change = (old->c_lflag ^ tty->termios->c_lflag) & ICANON; | |
1460 | if (canon_change) { | |
1461 | memset(&tty->read_flags, 0, sizeof tty->read_flags); | |
1462 | tty->canon_head = tty->read_tail; | |
1463 | tty->canon_data = 0; | |
1464 | tty->erasing = 0; | |
1465 | } | |
1466 | ||
1467 | if (canon_change && !L_ICANON(tty) && tty->read_cnt) | |
1468 | wake_up_interruptible(&tty->read_wait); | |
4edf1827 | 1469 | |
1da177e4 LT |
1470 | tty->icanon = (L_ICANON(tty) != 0); |
1471 | if (test_bit(TTY_HW_COOK_IN, &tty->flags)) { | |
1472 | tty->raw = 1; | |
1473 | tty->real_raw = 1; | |
33f0f88f | 1474 | n_tty_set_room(tty); |
1da177e4 LT |
1475 | return; |
1476 | } | |
1477 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || | |
1478 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1479 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1480 | I_PARMRK(tty)) { | |
1481 | memset(tty->process_char_map, 0, 256/8); | |
1482 | ||
1483 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1484 | set_bit('\r', tty->process_char_map); | |
1485 | if (I_INLCR(tty)) | |
1486 | set_bit('\n', tty->process_char_map); | |
1487 | ||
1488 | if (L_ICANON(tty)) { | |
1489 | set_bit(ERASE_CHAR(tty), tty->process_char_map); | |
1490 | set_bit(KILL_CHAR(tty), tty->process_char_map); | |
1491 | set_bit(EOF_CHAR(tty), tty->process_char_map); | |
1492 | set_bit('\n', tty->process_char_map); | |
1493 | set_bit(EOL_CHAR(tty), tty->process_char_map); | |
1494 | if (L_IEXTEN(tty)) { | |
1495 | set_bit(WERASE_CHAR(tty), | |
1496 | tty->process_char_map); | |
1497 | set_bit(LNEXT_CHAR(tty), | |
1498 | tty->process_char_map); | |
1499 | set_bit(EOL2_CHAR(tty), | |
1500 | tty->process_char_map); | |
1501 | if (L_ECHO(tty)) | |
1502 | set_bit(REPRINT_CHAR(tty), | |
1503 | tty->process_char_map); | |
1504 | } | |
1505 | } | |
1506 | if (I_IXON(tty)) { | |
1507 | set_bit(START_CHAR(tty), tty->process_char_map); | |
1508 | set_bit(STOP_CHAR(tty), tty->process_char_map); | |
1509 | } | |
1510 | if (L_ISIG(tty)) { | |
1511 | set_bit(INTR_CHAR(tty), tty->process_char_map); | |
1512 | set_bit(QUIT_CHAR(tty), tty->process_char_map); | |
1513 | set_bit(SUSP_CHAR(tty), tty->process_char_map); | |
1514 | } | |
1515 | clear_bit(__DISABLED_CHAR, tty->process_char_map); | |
1516 | tty->raw = 0; | |
1517 | tty->real_raw = 0; | |
1518 | } else { | |
1519 | tty->raw = 1; | |
1520 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && | |
1521 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1522 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
1523 | tty->real_raw = 1; | |
1524 | else | |
1525 | tty->real_raw = 0; | |
1526 | } | |
33f0f88f | 1527 | n_tty_set_room(tty); |
f34d7a5b AC |
1528 | /* The termios change make the tty ready for I/O */ |
1529 | wake_up_interruptible(&tty->write_wait); | |
1530 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1531 | } |
1532 | ||
1533 | /** | |
1534 | * n_tty_close - close the ldisc for this tty | |
1535 | * @tty: device | |
1536 | * | |
4edf1827 AC |
1537 | * Called from the terminal layer when this line discipline is |
1538 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1539 | * discipline change. The function will not be called while other |
1540 | * ldisc methods are in progress. | |
1541 | */ | |
4edf1827 | 1542 | |
1da177e4 LT |
1543 | static void n_tty_close(struct tty_struct *tty) |
1544 | { | |
1545 | n_tty_flush_buffer(tty); | |
1546 | if (tty->read_buf) { | |
1547 | free_buf(tty->read_buf); | |
1548 | tty->read_buf = NULL; | |
1549 | } | |
a88a69c9 JP |
1550 | if (tty->echo_buf) { |
1551 | free_buf(tty->echo_buf); | |
1552 | tty->echo_buf = NULL; | |
1553 | } | |
1da177e4 LT |
1554 | } |
1555 | ||
1556 | /** | |
1557 | * n_tty_open - open an ldisc | |
1558 | * @tty: terminal to open | |
1559 | * | |
4edf1827 | 1560 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1561 | * terminal device. Can sleep. Called serialized so that no |
1562 | * other events will occur in parallel. No further open will occur | |
1563 | * until a close. | |
1564 | */ | |
1565 | ||
1566 | static int n_tty_open(struct tty_struct *tty) | |
1567 | { | |
1568 | if (!tty) | |
1569 | return -EINVAL; | |
1570 | ||
a88a69c9 | 1571 | /* These are ugly. Currently a malloc failure here can panic */ |
1da177e4 LT |
1572 | if (!tty->read_buf) { |
1573 | tty->read_buf = alloc_buf(); | |
1574 | if (!tty->read_buf) | |
1575 | return -ENOMEM; | |
1576 | } | |
a88a69c9 JP |
1577 | if (!tty->echo_buf) { |
1578 | tty->echo_buf = alloc_buf(); | |
1579 | if (!tty->echo_buf) | |
1580 | return -ENOMEM; | |
1581 | } | |
1da177e4 | 1582 | memset(tty->read_buf, 0, N_TTY_BUF_SIZE); |
a88a69c9 | 1583 | memset(tty->echo_buf, 0, N_TTY_BUF_SIZE); |
1da177e4 LT |
1584 | reset_buffer_flags(tty); |
1585 | tty->column = 0; | |
1586 | n_tty_set_termios(tty, NULL); | |
1587 | tty->minimum_to_wake = 1; | |
1588 | tty->closing = 0; | |
1589 | return 0; | |
1590 | } | |
1591 | ||
1592 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1593 | { | |
1594 | if (tty->icanon) { | |
1595 | if (tty->canon_data) | |
1596 | return 1; | |
1597 | } else if (tty->read_cnt >= (amt ? amt : 1)) | |
1598 | return 1; | |
1599 | ||
1600 | return 0; | |
1601 | } | |
1602 | ||
1603 | /** | |
1604 | * copy_from_read_buf - copy read data directly | |
1605 | * @tty: terminal device | |
1606 | * @b: user data | |
1607 | * @nr: size of data | |
1608 | * | |
11a96d18 | 1609 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1610 | * ICANON is off; it copies characters straight from the tty queue to |
1611 | * user space directly. It can be profitably called twice; once to | |
1612 | * drain the space from the tail pointer to the (physical) end of the | |
1613 | * buffer, and once to drain the space from the (physical) beginning of | |
1614 | * the buffer to head pointer. | |
1615 | * | |
817d6d3b | 1616 | * Called under the tty->atomic_read_lock sem |
1da177e4 LT |
1617 | * |
1618 | */ | |
4edf1827 | 1619 | |
33f0f88f | 1620 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1621 | unsigned char __user **b, |
1622 | size_t *nr) | |
1623 | ||
1624 | { | |
1625 | int retval; | |
1626 | size_t n; | |
1627 | unsigned long flags; | |
1628 | ||
1629 | retval = 0; | |
1630 | spin_lock_irqsave(&tty->read_lock, flags); | |
1631 | n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail); | |
1632 | n = min(*nr, n); | |
1633 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1634 | if (n) { | |
1da177e4 LT |
1635 | retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n); |
1636 | n -= retval; | |
522ed776 | 1637 | tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n); |
1da177e4 LT |
1638 | spin_lock_irqsave(&tty->read_lock, flags); |
1639 | tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1); | |
1640 | tty->read_cnt -= n; | |
1641 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1642 | *b += n; | |
1643 | *nr -= n; | |
1644 | } | |
1645 | return retval; | |
1646 | } | |
1647 | ||
cc4191dc | 1648 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1649 | size_t, loff_t *); |
1da177e4 LT |
1650 | |
1651 | /** | |
1652 | * job_control - check job control | |
1653 | * @tty: tty | |
1654 | * @file: file handle | |
1655 | * | |
1656 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1657 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1658 | * error code if action should be taken. |
04f378b1 AC |
1659 | * |
1660 | * FIXME: | |
1661 | * Locking: None - redirected write test is safe, testing | |
1662 | * current->signal should possibly lock current->sighand | |
1663 | * pgrp locking ? | |
1da177e4 | 1664 | */ |
4edf1827 | 1665 | |
1da177e4 LT |
1666 | static int job_control(struct tty_struct *tty, struct file *file) |
1667 | { | |
1668 | /* Job control check -- must be done at start and after | |
1669 | every sleep (POSIX.1 7.1.1.4). */ | |
1670 | /* NOTE: not yet done after every sleep pending a thorough | |
1671 | check of the logic of this change. -- jlc */ | |
1672 | /* don't stop on /dev/console */ | |
1673 | if (file->f_op->write != redirected_tty_write && | |
1674 | current->signal->tty == tty) { | |
ab521dc0 | 1675 | if (!tty->pgrp) |
11a96d18 | 1676 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); |
ab521dc0 | 1677 | else if (task_pgrp(current) != tty->pgrp) { |
1da177e4 | 1678 | if (is_ignored(SIGTTIN) || |
3e7cd6c4 | 1679 | is_current_pgrp_orphaned()) |
1da177e4 | 1680 | return -EIO; |
ab521dc0 | 1681 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); |
040b6362 | 1682 | set_thread_flag(TIF_SIGPENDING); |
1da177e4 LT |
1683 | return -ERESTARTSYS; |
1684 | } | |
1685 | } | |
1686 | return 0; | |
1687 | } | |
4edf1827 | 1688 | |
1da177e4 LT |
1689 | |
1690 | /** | |
11a96d18 | 1691 | * n_tty_read - read function for tty |
1da177e4 LT |
1692 | * @tty: tty device |
1693 | * @file: file object | |
1694 | * @buf: userspace buffer pointer | |
1695 | * @nr: size of I/O | |
1696 | * | |
1697 | * Perform reads for the line discipline. We are guaranteed that the | |
1698 | * line discipline will not be closed under us but we may get multiple | |
1699 | * parallel readers and must handle this ourselves. We may also get | |
1700 | * a hangup. Always called in user context, may sleep. | |
1701 | * | |
1702 | * This code must be sure never to sleep through a hangup. | |
1703 | */ | |
4edf1827 | 1704 | |
11a96d18 | 1705 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1706 | unsigned char __user *buf, size_t nr) |
1707 | { | |
1708 | unsigned char __user *b = buf; | |
1709 | DECLARE_WAITQUEUE(wait, current); | |
1710 | int c; | |
1711 | int minimum, time; | |
1712 | ssize_t retval = 0; | |
1713 | ssize_t size; | |
1714 | long timeout; | |
1715 | unsigned long flags; | |
04f378b1 | 1716 | int packet; |
1da177e4 LT |
1717 | |
1718 | do_it_again: | |
1719 | ||
17b82060 | 1720 | BUG_ON(!tty->read_buf); |
1da177e4 LT |
1721 | |
1722 | c = job_control(tty, file); | |
4edf1827 | 1723 | if (c < 0) |
1da177e4 | 1724 | return c; |
4edf1827 | 1725 | |
1da177e4 LT |
1726 | minimum = time = 0; |
1727 | timeout = MAX_SCHEDULE_TIMEOUT; | |
1728 | if (!tty->icanon) { | |
1729 | time = (HZ / 10) * TIME_CHAR(tty); | |
1730 | minimum = MIN_CHAR(tty); | |
1731 | if (minimum) { | |
1732 | if (time) | |
1733 | tty->minimum_to_wake = 1; | |
1734 | else if (!waitqueue_active(&tty->read_wait) || | |
1735 | (tty->minimum_to_wake > minimum)) | |
1736 | tty->minimum_to_wake = minimum; | |
1737 | } else { | |
1738 | timeout = 0; | |
1739 | if (time) { | |
1740 | timeout = time; | |
1741 | time = 0; | |
1742 | } | |
1743 | tty->minimum_to_wake = minimum = 1; | |
1744 | } | |
1745 | } | |
1746 | ||
1747 | /* | |
1748 | * Internal serialization of reads. | |
1749 | */ | |
1750 | if (file->f_flags & O_NONBLOCK) { | |
70522e12 | 1751 | if (!mutex_trylock(&tty->atomic_read_lock)) |
1da177e4 | 1752 | return -EAGAIN; |
4edf1827 | 1753 | } else { |
70522e12 | 1754 | if (mutex_lock_interruptible(&tty->atomic_read_lock)) |
1da177e4 LT |
1755 | return -ERESTARTSYS; |
1756 | } | |
04f378b1 | 1757 | packet = tty->packet; |
1da177e4 LT |
1758 | |
1759 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
1760 | while (nr) { |
1761 | /* First test for status change. */ | |
04f378b1 | 1762 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
1763 | unsigned char cs; |
1764 | if (b != buf) | |
1765 | break; | |
04f378b1 | 1766 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
1767 | cs = tty->link->ctrl_status; |
1768 | tty->link->ctrl_status = 0; | |
04f378b1 | 1769 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 1770 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
1771 | retval = -EFAULT; |
1772 | b--; | |
1773 | break; | |
1774 | } | |
1775 | nr--; | |
1776 | break; | |
1777 | } | |
1778 | /* This statement must be first before checking for input | |
1779 | so that any interrupt will set the state back to | |
1780 | TASK_RUNNING. */ | |
1781 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 1782 | |
1da177e4 LT |
1783 | if (((minimum - (b - buf)) < tty->minimum_to_wake) && |
1784 | ((minimum - (b - buf)) >= 1)) | |
1785 | tty->minimum_to_wake = (minimum - (b - buf)); | |
4edf1827 | 1786 | |
1da177e4 LT |
1787 | if (!input_available_p(tty, 0)) { |
1788 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
1789 | retval = -EIO; | |
1790 | break; | |
1791 | } | |
1792 | if (tty_hung_up_p(file)) | |
1793 | break; | |
1794 | if (!timeout) | |
1795 | break; | |
1796 | if (file->f_flags & O_NONBLOCK) { | |
1797 | retval = -EAGAIN; | |
1798 | break; | |
1799 | } | |
1800 | if (signal_pending(current)) { | |
1801 | retval = -ERESTARTSYS; | |
1802 | break; | |
1803 | } | |
04f378b1 | 1804 | /* FIXME: does n_tty_set_room need locking ? */ |
33f0f88f | 1805 | n_tty_set_room(tty); |
1da177e4 | 1806 | timeout = schedule_timeout(timeout); |
1da177e4 LT |
1807 | continue; |
1808 | } | |
1809 | __set_current_state(TASK_RUNNING); | |
1810 | ||
1811 | /* Deal with packet mode. */ | |
04f378b1 | 1812 | if (packet && b == buf) { |
522ed776 | 1813 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
1814 | retval = -EFAULT; |
1815 | b--; | |
1816 | break; | |
1817 | } | |
1818 | nr--; | |
1819 | } | |
1820 | ||
1821 | if (tty->icanon) { | |
1822 | /* N.B. avoid overrun if nr == 0 */ | |
1823 | while (nr && tty->read_cnt) { | |
4edf1827 | 1824 | int eol; |
1da177e4 LT |
1825 | |
1826 | eol = test_and_clear_bit(tty->read_tail, | |
1827 | tty->read_flags); | |
1828 | c = tty->read_buf[tty->read_tail]; | |
1829 | spin_lock_irqsave(&tty->read_lock, flags); | |
1830 | tty->read_tail = ((tty->read_tail+1) & | |
1831 | (N_TTY_BUF_SIZE-1)); | |
1832 | tty->read_cnt--; | |
1833 | if (eol) { | |
1834 | /* this test should be redundant: | |
1835 | * we shouldn't be reading data if | |
1836 | * canon_data is 0 | |
1837 | */ | |
1838 | if (--tty->canon_data < 0) | |
1839 | tty->canon_data = 0; | |
1840 | } | |
1841 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1842 | ||
1843 | if (!eol || (c != __DISABLED_CHAR)) { | |
522ed776 | 1844 | if (tty_put_user(tty, c, b++)) { |
1da177e4 LT |
1845 | retval = -EFAULT; |
1846 | b--; | |
1847 | break; | |
1848 | } | |
1849 | nr--; | |
1850 | } | |
522ed776 MT |
1851 | if (eol) { |
1852 | tty_audit_push(tty); | |
1da177e4 | 1853 | break; |
522ed776 | 1854 | } |
1da177e4 LT |
1855 | } |
1856 | if (retval) | |
1857 | break; | |
1858 | } else { | |
1859 | int uncopied; | |
04f378b1 AC |
1860 | /* The copy function takes the read lock and handles |
1861 | locking internally for this case */ | |
1da177e4 LT |
1862 | uncopied = copy_from_read_buf(tty, &b, &nr); |
1863 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
1864 | if (uncopied) { | |
1865 | retval = -EFAULT; | |
1866 | break; | |
1867 | } | |
1868 | } | |
1869 | ||
1870 | /* If there is enough space in the read buffer now, let the | |
1871 | * low-level driver know. We use n_tty_chars_in_buffer() to | |
1872 | * check the buffer, as it now knows about canonical mode. | |
1873 | * Otherwise, if the driver is throttled and the line is | |
1874 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
1875 | * we won't get any more characters. | |
1876 | */ | |
289a1e99 PM |
1877 | if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) { |
1878 | n_tty_set_room(tty); | |
1da177e4 | 1879 | check_unthrottle(tty); |
289a1e99 | 1880 | } |
1da177e4 LT |
1881 | |
1882 | if (b - buf >= minimum) | |
1883 | break; | |
1884 | if (time) | |
1885 | timeout = time; | |
1886 | } | |
70522e12 | 1887 | mutex_unlock(&tty->atomic_read_lock); |
1da177e4 LT |
1888 | remove_wait_queue(&tty->read_wait, &wait); |
1889 | ||
1890 | if (!waitqueue_active(&tty->read_wait)) | |
1891 | tty->minimum_to_wake = minimum; | |
1892 | ||
1893 | __set_current_state(TASK_RUNNING); | |
1894 | size = b - buf; | |
1895 | if (size) { | |
1896 | retval = size; | |
1897 | if (nr) | |
4edf1827 | 1898 | clear_bit(TTY_PUSH, &tty->flags); |
1da177e4 LT |
1899 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) |
1900 | goto do_it_again; | |
1901 | ||
33f0f88f | 1902 | n_tty_set_room(tty); |
1da177e4 LT |
1903 | return retval; |
1904 | } | |
1905 | ||
1906 | /** | |
11a96d18 | 1907 | * n_tty_write - write function for tty |
1da177e4 LT |
1908 | * @tty: tty device |
1909 | * @file: file object | |
1910 | * @buf: userspace buffer pointer | |
1911 | * @nr: size of I/O | |
1912 | * | |
a88a69c9 | 1913 | * Write function of the terminal device. This is serialized with |
1da177e4 | 1914 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
1915 | * and other such events. Since the receive code will echo characters, |
1916 | * thus calling driver write methods, the output_lock is used in | |
1917 | * the output processing functions called here as well as in the | |
1918 | * echo processing function to protect the column state and space | |
1919 | * left in the buffer. | |
1da177e4 LT |
1920 | * |
1921 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
1922 | * |
1923 | * Locking: output_lock to protect column state and space left | |
1924 | * (note that the process_output*() functions take this | |
1925 | * lock themselves) | |
1da177e4 | 1926 | */ |
4edf1827 | 1927 | |
11a96d18 | 1928 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 1929 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
1930 | { |
1931 | const unsigned char *b = buf; | |
1932 | DECLARE_WAITQUEUE(wait, current); | |
1933 | int c; | |
1934 | ssize_t retval = 0; | |
1935 | ||
1936 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
1937 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
1938 | retval = tty_check_change(tty); | |
1939 | if (retval) | |
1940 | return retval; | |
1941 | } | |
1942 | ||
a88a69c9 JP |
1943 | /* Write out any echoed characters that are still pending */ |
1944 | process_echoes(tty); | |
1945 | ||
1da177e4 LT |
1946 | add_wait_queue(&tty->write_wait, &wait); |
1947 | while (1) { | |
1948 | set_current_state(TASK_INTERRUPTIBLE); | |
1949 | if (signal_pending(current)) { | |
1950 | retval = -ERESTARTSYS; | |
1951 | break; | |
1952 | } | |
1953 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
1954 | retval = -EIO; | |
1955 | break; | |
1956 | } | |
1957 | if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
1958 | while (nr > 0) { | |
a88a69c9 | 1959 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
1960 | if (num < 0) { |
1961 | if (num == -EAGAIN) | |
1962 | break; | |
1963 | retval = num; | |
1964 | goto break_out; | |
1965 | } | |
1966 | b += num; | |
1967 | nr -= num; | |
1968 | if (nr == 0) | |
1969 | break; | |
1970 | c = *b; | |
a88a69c9 | 1971 | if (process_output(c, tty) < 0) |
1da177e4 LT |
1972 | break; |
1973 | b++; nr--; | |
1974 | } | |
f34d7a5b AC |
1975 | if (tty->ops->flush_chars) |
1976 | tty->ops->flush_chars(tty); | |
1da177e4 | 1977 | } else { |
d6afe27b | 1978 | while (nr > 0) { |
f34d7a5b | 1979 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
1980 | if (c < 0) { |
1981 | retval = c; | |
1982 | goto break_out; | |
1983 | } | |
1984 | if (!c) | |
1985 | break; | |
1986 | b += c; | |
1987 | nr -= c; | |
1da177e4 | 1988 | } |
1da177e4 LT |
1989 | } |
1990 | if (!nr) | |
1991 | break; | |
1992 | if (file->f_flags & O_NONBLOCK) { | |
1993 | retval = -EAGAIN; | |
1994 | break; | |
1995 | } | |
1996 | schedule(); | |
1997 | } | |
1998 | break_out: | |
1999 | __set_current_state(TASK_RUNNING); | |
2000 | remove_wait_queue(&tty->write_wait, &wait); | |
2001 | return (b - buf) ? b - buf : retval; | |
2002 | } | |
2003 | ||
2004 | /** | |
11a96d18 | 2005 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2006 | * @tty: terminal device |
2007 | * @file: file accessing it | |
2008 | * @wait: poll table | |
2009 | * | |
2010 | * Called when the line discipline is asked to poll() for data or | |
2011 | * for special events. This code is not serialized with respect to | |
2012 | * other events save open/close. | |
2013 | * | |
2014 | * This code must be sure never to sleep through a hangup. | |
2015 | * Called without the kernel lock held - fine | |
1da177e4 | 2016 | */ |
4edf1827 | 2017 | |
11a96d18 | 2018 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2019 | poll_table *wait) |
1da177e4 LT |
2020 | { |
2021 | unsigned int mask = 0; | |
2022 | ||
2023 | poll_wait(file, &tty->read_wait, wait); | |
2024 | poll_wait(file, &tty->write_wait, wait); | |
2025 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2026 | mask |= POLLIN | POLLRDNORM; | |
2027 | if (tty->packet && tty->link->ctrl_status) | |
2028 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2029 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2030 | mask |= POLLHUP; | |
2031 | if (tty_hung_up_p(file)) | |
2032 | mask |= POLLHUP; | |
2033 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2034 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
2035 | tty->minimum_to_wake = MIN_CHAR(tty); | |
2036 | else | |
2037 | tty->minimum_to_wake = 1; | |
2038 | } | |
f34d7a5b AC |
2039 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2040 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2041 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2042 | mask |= POLLOUT | POLLWRNORM; |
2043 | return mask; | |
2044 | } | |
2045 | ||
47afa7a5 AC |
2046 | static unsigned long inq_canon(struct tty_struct *tty) |
2047 | { | |
2048 | int nr, head, tail; | |
2049 | ||
17b82060 | 2050 | if (!tty->canon_data) |
47afa7a5 AC |
2051 | return 0; |
2052 | head = tty->canon_head; | |
2053 | tail = tty->read_tail; | |
2054 | nr = (head - tail) & (N_TTY_BUF_SIZE-1); | |
2055 | /* Skip EOF-chars.. */ | |
2056 | while (head != tail) { | |
2057 | if (test_bit(tail, tty->read_flags) && | |
2058 | tty->read_buf[tail] == __DISABLED_CHAR) | |
2059 | nr--; | |
2060 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
2061 | } | |
2062 | return nr; | |
2063 | } | |
2064 | ||
2065 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2066 | unsigned int cmd, unsigned long arg) | |
2067 | { | |
2068 | int retval; | |
2069 | ||
2070 | switch (cmd) { | |
2071 | case TIOCOUTQ: | |
2072 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2073 | case TIOCINQ: | |
17b82060 | 2074 | /* FIXME: Locking */ |
47afa7a5 AC |
2075 | retval = tty->read_cnt; |
2076 | if (L_ICANON(tty)) | |
2077 | retval = inq_canon(tty); | |
2078 | return put_user(retval, (unsigned int __user *) arg); | |
2079 | default: | |
2080 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2081 | } | |
2082 | } | |
2083 | ||
a352def2 | 2084 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2085 | .magic = TTY_LDISC_MAGIC, |
2086 | .name = "n_tty", | |
2087 | .open = n_tty_open, | |
2088 | .close = n_tty_close, | |
2089 | .flush_buffer = n_tty_flush_buffer, | |
2090 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2091 | .read = n_tty_read, |
2092 | .write = n_tty_write, | |
e10cc1df PF |
2093 | .ioctl = n_tty_ioctl, |
2094 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2095 | .poll = n_tty_poll, |
e10cc1df PF |
2096 | .receive_buf = n_tty_receive_buf, |
2097 | .write_wakeup = n_tty_write_wakeup | |
1da177e4 | 2098 | }; |