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