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Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * n_tty.c --- implements the N_TTY line discipline. | |
4edf1827 | 3 | * |
1da177e4 LT |
4 | * This code used to be in tty_io.c, but things are getting hairy |
5 | * enough that it made sense to split things off. (The N_TTY | |
6 | * processing has changed so much that it's hardly recognizable, | |
7 | * anyway...) | |
8 | * | |
9 | * Note that the open routine for N_TTY is guaranteed never to return | |
10 | * an error. This is because Linux will fall back to setting a line | |
4edf1827 | 11 | * to N_TTY if it can not switch to any other line discipline. |
1da177e4 LT |
12 | * |
13 | * Written by Theodore Ts'o, Copyright 1994. | |
4edf1827 | 14 | * |
1da177e4 LT |
15 | * This file also contains code originally written by Linus Torvalds, |
16 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. | |
4edf1827 | 17 | * |
1da177e4 LT |
18 | * This file may be redistributed under the terms of the GNU General Public |
19 | * License. | |
20 | * | |
21 | * Reduced memory usage for older ARM systems - Russell King. | |
22 | * | |
4edf1827 | 23 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
1da177e4 LT |
24 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
25 | * who actually finally proved there really was a race. | |
26 | * | |
27 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to | |
28 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. | |
11a96d18 | 29 | * Also fixed a bug in BLOCKING mode where n_tty_write returns |
1da177e4 LT |
30 | * EAGAIN |
31 | */ | |
32 | ||
33 | #include <linux/types.h> | |
34 | #include <linux/major.h> | |
35 | #include <linux/errno.h> | |
36 | #include <linux/signal.h> | |
37 | #include <linux/fcntl.h> | |
38 | #include <linux/sched.h> | |
39 | #include <linux/interrupt.h> | |
40 | #include <linux/tty.h> | |
41 | #include <linux/timer.h> | |
42 | #include <linux/ctype.h> | |
43 | #include <linux/mm.h> | |
44 | #include <linux/string.h> | |
45 | #include <linux/slab.h> | |
46 | #include <linux/poll.h> | |
47 | #include <linux/bitops.h> | |
522ed776 MT |
48 | #include <linux/audit.h> |
49 | #include <linux/file.h> | |
300a6204 | 50 | #include <linux/uaccess.h> |
572b9adb | 51 | #include <linux/module.h> |
593fb1ae | 52 | #include <linux/ratelimit.h> |
1da177e4 | 53 | |
1da177e4 LT |
54 | |
55 | /* number of characters left in xmit buffer before select has we have room */ | |
56 | #define WAKEUP_CHARS 256 | |
57 | ||
58 | /* | |
59 | * This defines the low- and high-watermarks for throttling and | |
60 | * unthrottling the TTY driver. These watermarks are used for | |
61 | * controlling the space in the read buffer. | |
62 | */ | |
63 | #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ | |
bbd20759 | 64 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
1da177e4 | 65 | |
a88a69c9 JP |
66 | /* |
67 | * Special byte codes used in the echo buffer to represent operations | |
68 | * or special handling of characters. Bytes in the echo buffer that | |
69 | * are not part of such special blocks are treated as normal character | |
70 | * codes. | |
71 | */ | |
72 | #define ECHO_OP_START 0xff | |
73 | #define ECHO_OP_MOVE_BACK_COL 0x80 | |
74 | #define ECHO_OP_SET_CANON_COL 0x81 | |
75 | #define ECHO_OP_ERASE_TAB 0x82 | |
76 | ||
70ece7a7 | 77 | struct n_tty_data { |
53c5ee2c JS |
78 | unsigned int column; |
79 | unsigned long overrun_time; | |
80 | int num_overrun; | |
81 | ||
82 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; | |
83 | unsigned char echo_overrun:1; | |
3fe780b3 JS |
84 | |
85 | DECLARE_BITMAP(process_char_map, 256); | |
86 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); | |
ba2e68ac JS |
87 | |
88 | char *read_buf; | |
89 | int read_head; | |
90 | int read_tail; | |
91 | int read_cnt; | |
92 | ||
93 | unsigned char *echo_buf; | |
94 | unsigned int echo_pos; | |
95 | unsigned int echo_cnt; | |
96 | ||
97 | int canon_data; | |
98 | unsigned long canon_head; | |
99 | unsigned int canon_column; | |
bddc7152 JS |
100 | |
101 | struct mutex atomic_read_lock; | |
102 | struct mutex output_lock; | |
103 | struct mutex echo_lock; | |
98001214 | 104 | raw_spinlock_t read_lock; |
70ece7a7 JS |
105 | }; |
106 | ||
522ed776 MT |
107 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
108 | unsigned char __user *ptr) | |
109 | { | |
53c5ee2c JS |
110 | struct n_tty_data *ldata = tty->disc_data; |
111 | ||
112 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
113 | return put_user(x, ptr); |
114 | } | |
115 | ||
55db4c64 LT |
116 | /** |
117 | * n_tty_set__room - receive space | |
118 | * @tty: terminal | |
119 | * | |
120 | * Called by the driver to find out how much data it is | |
121 | * permitted to feed to the line discipline without any being lost | |
122 | * and thus to manage flow control. Not serialized. Answers for the | |
123 | * "instant". | |
124 | */ | |
125 | ||
126 | static void n_tty_set_room(struct tty_struct *tty) | |
127 | { | |
53c5ee2c | 128 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 129 | int left; |
55db4c64 LT |
130 | int old_left; |
131 | ||
ba2e68ac | 132 | /* ldata->read_cnt is not read locked ? */ |
090abf7b JA |
133 | if (I_PARMRK(tty)) { |
134 | /* Multiply read_cnt by 3, since each byte might take up to | |
135 | * three times as many spaces when PARMRK is set (depending on | |
136 | * its flags, e.g. parity error). */ | |
ba2e68ac | 137 | left = N_TTY_BUF_SIZE - ldata->read_cnt * 3 - 1; |
090abf7b | 138 | } else |
ba2e68ac | 139 | left = N_TTY_BUF_SIZE - ldata->read_cnt - 1; |
090abf7b | 140 | |
55db4c64 LT |
141 | /* |
142 | * If we are doing input canonicalization, and there are no | |
143 | * pending newlines, let characters through without limit, so | |
144 | * that erase characters will be handled. Other excess | |
145 | * characters will be beeped. | |
146 | */ | |
147 | if (left <= 0) | |
ba2e68ac | 148 | left = ldata->icanon && !ldata->canon_data; |
55db4c64 LT |
149 | old_left = tty->receive_room; |
150 | tty->receive_room = left; | |
151 | ||
152 | /* Did this open up the receive buffer? We may need to flip */ | |
ecbbfd44 JS |
153 | if (left && !old_left) { |
154 | WARN_RATELIMIT(tty->port->itty == NULL, | |
cadf7486 | 155 | "scheduling with invalid itty\n"); |
ecbbfd44 JS |
156 | schedule_work(&tty->port->buf.work); |
157 | } | |
55db4c64 LT |
158 | } |
159 | ||
57c94121 | 160 | static void put_tty_queue_nolock(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 161 | { |
ba2e68ac JS |
162 | if (ldata->read_cnt < N_TTY_BUF_SIZE) { |
163 | ldata->read_buf[ldata->read_head] = c; | |
164 | ldata->read_head = (ldata->read_head + 1) & (N_TTY_BUF_SIZE-1); | |
165 | ldata->read_cnt++; | |
1da177e4 LT |
166 | } |
167 | } | |
168 | ||
17b82060 AC |
169 | /** |
170 | * put_tty_queue - add character to tty | |
171 | * @c: character | |
57c94121 | 172 | * @ldata: n_tty data |
17b82060 AC |
173 | * |
174 | * Add a character to the tty read_buf queue. This is done under the | |
175 | * read_lock to serialize character addition and also to protect us | |
176 | * against parallel reads or flushes | |
177 | */ | |
178 | ||
57c94121 | 179 | static void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 LT |
180 | { |
181 | unsigned long flags; | |
182 | /* | |
183 | * The problem of stomping on the buffers ends here. | |
184 | * Why didn't anyone see this one coming? --AJK | |
185 | */ | |
98001214 | 186 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
57c94121 | 187 | put_tty_queue_nolock(c, ldata); |
98001214 | 188 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
189 | } |
190 | ||
191 | /** | |
192 | * check_unthrottle - allow new receive data | |
193 | * @tty; tty device | |
194 | * | |
17b82060 AC |
195 | * Check whether to call the driver unthrottle functions |
196 | * | |
70522e12 | 197 | * Can sleep, may be called under the atomic_read_lock mutex but |
1da177e4 LT |
198 | * this is not guaranteed. |
199 | */ | |
4edf1827 | 200 | static void check_unthrottle(struct tty_struct *tty) |
1da177e4 | 201 | { |
39c2e60f AC |
202 | if (tty->count) |
203 | tty_unthrottle(tty); | |
1da177e4 LT |
204 | } |
205 | ||
206 | /** | |
207 | * reset_buffer_flags - reset buffer state | |
208 | * @tty: terminal to reset | |
209 | * | |
4edf1827 | 210 | * Reset the read buffer counters, clear the flags, |
1da177e4 LT |
211 | * and make sure the driver is unthrottled. Called |
212 | * from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 AC |
213 | * |
214 | * Locking: tty_read_lock for read fields. | |
1da177e4 | 215 | */ |
a88a69c9 | 216 | |
1da177e4 LT |
217 | static void reset_buffer_flags(struct tty_struct *tty) |
218 | { | |
53c5ee2c | 219 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
220 | unsigned long flags; |
221 | ||
98001214 | 222 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 223 | ldata->read_head = ldata->read_tail = ldata->read_cnt = 0; |
98001214 | 224 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
a88a69c9 | 225 | |
bddc7152 | 226 | mutex_lock(&ldata->echo_lock); |
ba2e68ac | 227 | ldata->echo_pos = ldata->echo_cnt = ldata->echo_overrun = 0; |
bddc7152 | 228 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 | 229 | |
ba2e68ac | 230 | ldata->canon_head = ldata->canon_data = ldata->erasing = 0; |
3fe780b3 | 231 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
55db4c64 | 232 | n_tty_set_room(tty); |
1da177e4 LT |
233 | } |
234 | ||
235 | /** | |
236 | * n_tty_flush_buffer - clean input queue | |
237 | * @tty: terminal device | |
238 | * | |
239 | * Flush the input buffer. Called when the line discipline is | |
240 | * being closed, when the tty layer wants the buffer flushed (eg | |
241 | * at hangup) or when the N_TTY line discipline internally has to | |
242 | * clean the pending queue (for example some signals). | |
243 | * | |
17b82060 | 244 | * Locking: ctrl_lock, read_lock. |
1da177e4 | 245 | */ |
4edf1827 AC |
246 | |
247 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 248 | { |
04f378b1 | 249 | unsigned long flags; |
1da177e4 LT |
250 | /* clear everything and unthrottle the driver */ |
251 | reset_buffer_flags(tty); | |
4edf1827 | 252 | |
1da177e4 LT |
253 | if (!tty->link) |
254 | return; | |
255 | ||
04f378b1 | 256 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
1da177e4 LT |
257 | if (tty->link->packet) { |
258 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
259 | wake_up_interruptible(&tty->link->read_wait); | |
260 | } | |
04f378b1 | 261 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1da177e4 LT |
262 | } |
263 | ||
264 | /** | |
265 | * n_tty_chars_in_buffer - report available bytes | |
266 | * @tty: tty device | |
267 | * | |
268 | * Report the number of characters buffered to be delivered to user | |
4edf1827 | 269 | * at this instant in time. |
17b82060 AC |
270 | * |
271 | * Locking: read_lock | |
1da177e4 | 272 | */ |
4edf1827 | 273 | |
1da177e4 LT |
274 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
275 | { | |
53c5ee2c | 276 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
277 | unsigned long flags; |
278 | ssize_t n = 0; | |
279 | ||
98001214 | 280 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
53c5ee2c | 281 | if (!ldata->icanon) { |
ba2e68ac JS |
282 | n = ldata->read_cnt; |
283 | } else if (ldata->canon_data) { | |
284 | n = (ldata->canon_head > ldata->read_tail) ? | |
285 | ldata->canon_head - ldata->read_tail : | |
286 | ldata->canon_head + (N_TTY_BUF_SIZE - ldata->read_tail); | |
1da177e4 | 287 | } |
98001214 | 288 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
289 | return n; |
290 | } | |
291 | ||
292 | /** | |
293 | * is_utf8_continuation - utf8 multibyte check | |
294 | * @c: byte to check | |
295 | * | |
296 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
297 | * character. We use this to correctly compute the on screen size | |
298 | * of the character when printing | |
299 | */ | |
4edf1827 | 300 | |
1da177e4 LT |
301 | static inline int is_utf8_continuation(unsigned char c) |
302 | { | |
303 | return (c & 0xc0) == 0x80; | |
304 | } | |
305 | ||
306 | /** | |
307 | * is_continuation - multibyte check | |
308 | * @c: byte to check | |
309 | * | |
310 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
311 | * character and the terminal is in unicode mode. | |
312 | */ | |
4edf1827 | 313 | |
1da177e4 LT |
314 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
315 | { | |
316 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
317 | } | |
318 | ||
319 | /** | |
a88a69c9 | 320 | * do_output_char - output one character |
1da177e4 LT |
321 | * @c: character (or partial unicode symbol) |
322 | * @tty: terminal device | |
a88a69c9 | 323 | * @space: space available in tty driver write buffer |
1da177e4 | 324 | * |
a88a69c9 JP |
325 | * This is a helper function that handles one output character |
326 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
327 | * doing OPOST processing and putting the results in the |
328 | * tty driver's write buffer. | |
a88a69c9 JP |
329 | * |
330 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
331 | * and NLDLY. They simply aren't relevant in the world today. | |
332 | * If you ever need them, add them here. | |
1da177e4 | 333 | * |
a88a69c9 JP |
334 | * Returns the number of bytes of buffer space used or -1 if |
335 | * no space left. | |
336 | * | |
337 | * Locking: should be called under the output_lock to protect | |
338 | * the column state and space left in the buffer | |
1da177e4 | 339 | */ |
4edf1827 | 340 | |
a88a69c9 | 341 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 342 | { |
53c5ee2c | 343 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 344 | int spaces; |
1da177e4 | 345 | |
1da177e4 LT |
346 | if (!space) |
347 | return -1; | |
300a6204 | 348 | |
a88a69c9 JP |
349 | switch (c) { |
350 | case '\n': | |
351 | if (O_ONLRET(tty)) | |
53c5ee2c | 352 | ldata->column = 0; |
a88a69c9 JP |
353 | if (O_ONLCR(tty)) { |
354 | if (space < 2) | |
355 | return -1; | |
ba2e68ac | 356 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 357 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
358 | return 2; |
359 | } | |
ba2e68ac | 360 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
361 | break; |
362 | case '\r': | |
53c5ee2c | 363 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
364 | return 0; |
365 | if (O_OCRNL(tty)) { | |
366 | c = '\n'; | |
367 | if (O_ONLRET(tty)) | |
ba2e68ac | 368 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 369 | break; |
a88a69c9 | 370 | } |
ba2e68ac | 371 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
372 | break; |
373 | case '\t': | |
53c5ee2c | 374 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
375 | if (O_TABDLY(tty) == XTABS) { |
376 | if (space < spaces) | |
377 | return -1; | |
53c5ee2c | 378 | ldata->column += spaces; |
a88a69c9 JP |
379 | tty->ops->write(tty, " ", spaces); |
380 | return spaces; | |
1da177e4 | 381 | } |
53c5ee2c | 382 | ldata->column += spaces; |
a88a69c9 JP |
383 | break; |
384 | case '\b': | |
53c5ee2c JS |
385 | if (ldata->column > 0) |
386 | ldata->column--; | |
a88a69c9 JP |
387 | break; |
388 | default: | |
a59c0d6f JP |
389 | if (!iscntrl(c)) { |
390 | if (O_OLCUC(tty)) | |
391 | c = toupper(c); | |
392 | if (!is_continuation(c, tty)) | |
53c5ee2c | 393 | ldata->column++; |
a59c0d6f | 394 | } |
a88a69c9 | 395 | break; |
1da177e4 | 396 | } |
a88a69c9 | 397 | |
f34d7a5b | 398 | tty_put_char(tty, c); |
a88a69c9 JP |
399 | return 1; |
400 | } | |
401 | ||
402 | /** | |
403 | * process_output - output post processor | |
404 | * @c: character (or partial unicode symbol) | |
405 | * @tty: terminal device | |
406 | * | |
ee5aa7b8 JP |
407 | * Output one character with OPOST processing. |
408 | * Returns -1 when the output device is full and the character | |
409 | * must be retried. | |
a88a69c9 JP |
410 | * |
411 | * Locking: output_lock to protect column state and space left | |
412 | * (also, this is called from n_tty_write under the | |
413 | * tty layer write lock) | |
414 | */ | |
415 | ||
416 | static int process_output(unsigned char c, struct tty_struct *tty) | |
417 | { | |
bddc7152 | 418 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
419 | int space, retval; |
420 | ||
bddc7152 | 421 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
422 | |
423 | space = tty_write_room(tty); | |
424 | retval = do_output_char(c, tty, space); | |
425 | ||
bddc7152 | 426 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
427 | if (retval < 0) |
428 | return -1; | |
429 | else | |
430 | return 0; | |
1da177e4 LT |
431 | } |
432 | ||
433 | /** | |
a88a69c9 | 434 | * process_output_block - block post processor |
1da177e4 | 435 | * @tty: terminal device |
ee5aa7b8 JP |
436 | * @buf: character buffer |
437 | * @nr: number of bytes to output | |
438 | * | |
439 | * Output a block of characters with OPOST processing. | |
440 | * Returns the number of characters output. | |
1da177e4 LT |
441 | * |
442 | * This path is used to speed up block console writes, among other | |
443 | * things when processing blocks of output data. It handles only | |
444 | * the simple cases normally found and helps to generate blocks of | |
445 | * symbols for the console driver and thus improve performance. | |
446 | * | |
a88a69c9 JP |
447 | * Locking: output_lock to protect column state and space left |
448 | * (also, this is called from n_tty_write under the | |
449 | * tty layer write lock) | |
1da177e4 | 450 | */ |
4edf1827 | 451 | |
a88a69c9 JP |
452 | static ssize_t process_output_block(struct tty_struct *tty, |
453 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 454 | { |
53c5ee2c | 455 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 456 | int space; |
bbd20759 | 457 | int i; |
1da177e4 LT |
458 | const unsigned char *cp; |
459 | ||
bddc7152 | 460 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 461 | |
f34d7a5b | 462 | space = tty_write_room(tty); |
300a6204 | 463 | if (!space) { |
bddc7152 | 464 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 465 | return 0; |
a88a69c9 | 466 | } |
1da177e4 LT |
467 | if (nr > space) |
468 | nr = space; | |
469 | ||
470 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
471 | unsigned char c = *cp; |
472 | ||
473 | switch (c) { | |
1da177e4 LT |
474 | case '\n': |
475 | if (O_ONLRET(tty)) | |
53c5ee2c | 476 | ldata->column = 0; |
1da177e4 LT |
477 | if (O_ONLCR(tty)) |
478 | goto break_out; | |
ba2e68ac | 479 | ldata->canon_column = ldata->column; |
1da177e4 LT |
480 | break; |
481 | case '\r': | |
53c5ee2c | 482 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
483 | goto break_out; |
484 | if (O_OCRNL(tty)) | |
485 | goto break_out; | |
ba2e68ac | 486 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
487 | break; |
488 | case '\t': | |
489 | goto break_out; | |
490 | case '\b': | |
53c5ee2c JS |
491 | if (ldata->column > 0) |
492 | ldata->column--; | |
1da177e4 LT |
493 | break; |
494 | default: | |
a59c0d6f JP |
495 | if (!iscntrl(c)) { |
496 | if (O_OLCUC(tty)) | |
497 | goto break_out; | |
498 | if (!is_continuation(c, tty)) | |
53c5ee2c | 499 | ldata->column++; |
a59c0d6f | 500 | } |
1da177e4 LT |
501 | break; |
502 | } | |
503 | } | |
504 | break_out: | |
f34d7a5b | 505 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 506 | |
bddc7152 | 507 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
508 | return i; |
509 | } | |
510 | ||
a88a69c9 JP |
511 | /** |
512 | * process_echoes - write pending echo characters | |
513 | * @tty: terminal device | |
514 | * | |
515 | * Write previously buffered echo (and other ldisc-generated) | |
516 | * characters to the tty. | |
517 | * | |
518 | * Characters generated by the ldisc (including echoes) need to | |
519 | * be buffered because the driver's write buffer can fill during | |
520 | * heavy program output. Echoing straight to the driver will | |
521 | * often fail under these conditions, causing lost characters and | |
522 | * resulting mismatches of ldisc state information. | |
523 | * | |
524 | * Since the ldisc state must represent the characters actually sent | |
525 | * to the driver at the time of the write, operations like certain | |
526 | * changes in column state are also saved in the buffer and executed | |
527 | * here. | |
528 | * | |
529 | * A circular fifo buffer is used so that the most recent characters | |
530 | * are prioritized. Also, when control characters are echoed with a | |
531 | * prefixed "^", the pair is treated atomically and thus not separated. | |
532 | * | |
533 | * Locking: output_lock to protect column state and space left, | |
534 | * echo_lock to protect the echo buffer | |
535 | */ | |
536 | ||
537 | static void process_echoes(struct tty_struct *tty) | |
538 | { | |
53c5ee2c | 539 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
540 | int space, nr; |
541 | unsigned char c; | |
542 | unsigned char *cp, *buf_end; | |
543 | ||
ba2e68ac | 544 | if (!ldata->echo_cnt) |
a88a69c9 JP |
545 | return; |
546 | ||
bddc7152 JS |
547 | mutex_lock(&ldata->output_lock); |
548 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
549 | |
550 | space = tty_write_room(tty); | |
551 | ||
ba2e68ac JS |
552 | buf_end = ldata->echo_buf + N_TTY_BUF_SIZE; |
553 | cp = ldata->echo_buf + ldata->echo_pos; | |
554 | nr = ldata->echo_cnt; | |
a88a69c9 JP |
555 | while (nr > 0) { |
556 | c = *cp; | |
557 | if (c == ECHO_OP_START) { | |
558 | unsigned char op; | |
559 | unsigned char *opp; | |
560 | int no_space_left = 0; | |
561 | ||
562 | /* | |
563 | * If the buffer byte is the start of a multi-byte | |
564 | * operation, get the next byte, which is either the | |
565 | * op code or a control character value. | |
566 | */ | |
567 | opp = cp + 1; | |
568 | if (opp == buf_end) | |
569 | opp -= N_TTY_BUF_SIZE; | |
570 | op = *opp; | |
300a6204 | 571 | |
a88a69c9 JP |
572 | switch (op) { |
573 | unsigned int num_chars, num_bs; | |
574 | ||
575 | case ECHO_OP_ERASE_TAB: | |
576 | if (++opp == buf_end) | |
577 | opp -= N_TTY_BUF_SIZE; | |
578 | num_chars = *opp; | |
579 | ||
580 | /* | |
581 | * Determine how many columns to go back | |
582 | * in order to erase the tab. | |
583 | * This depends on the number of columns | |
584 | * used by other characters within the tab | |
585 | * area. If this (modulo 8) count is from | |
586 | * the start of input rather than from a | |
587 | * previous tab, we offset by canon column. | |
588 | * Otherwise, tab spacing is normal. | |
589 | */ | |
590 | if (!(num_chars & 0x80)) | |
ba2e68ac | 591 | num_chars += ldata->canon_column; |
a88a69c9 JP |
592 | num_bs = 8 - (num_chars & 7); |
593 | ||
594 | if (num_bs > space) { | |
595 | no_space_left = 1; | |
596 | break; | |
597 | } | |
598 | space -= num_bs; | |
599 | while (num_bs--) { | |
600 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
601 | if (ldata->column > 0) |
602 | ldata->column--; | |
a88a69c9 JP |
603 | } |
604 | cp += 3; | |
605 | nr -= 3; | |
606 | break; | |
607 | ||
608 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 609 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
610 | cp += 2; |
611 | nr -= 2; | |
612 | break; | |
613 | ||
614 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
615 | if (ldata->column > 0) |
616 | ldata->column--; | |
a88a69c9 JP |
617 | cp += 2; |
618 | nr -= 2; | |
619 | break; | |
620 | ||
621 | case ECHO_OP_START: | |
622 | /* This is an escaped echo op start code */ | |
623 | if (!space) { | |
624 | no_space_left = 1; | |
625 | break; | |
626 | } | |
627 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 628 | ldata->column++; |
a88a69c9 JP |
629 | space--; |
630 | cp += 2; | |
631 | nr -= 2; | |
632 | break; | |
633 | ||
634 | default: | |
a88a69c9 | 635 | /* |
62b26358 JP |
636 | * If the op is not a special byte code, |
637 | * it is a ctrl char tagged to be echoed | |
638 | * as "^X" (where X is the letter | |
639 | * representing the control char). | |
640 | * Note that we must ensure there is | |
641 | * enough space for the whole ctrl pair. | |
642 | * | |
a88a69c9 | 643 | */ |
62b26358 JP |
644 | if (space < 2) { |
645 | no_space_left = 1; | |
646 | break; | |
647 | } | |
648 | tty_put_char(tty, '^'); | |
649 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 650 | ldata->column += 2; |
62b26358 | 651 | space -= 2; |
a88a69c9 JP |
652 | cp += 2; |
653 | nr -= 2; | |
654 | } | |
655 | ||
656 | if (no_space_left) | |
657 | break; | |
658 | } else { | |
ee5aa7b8 JP |
659 | if (O_OPOST(tty) && |
660 | !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
661 | int retval = do_output_char(c, tty, space); | |
662 | if (retval < 0) | |
663 | break; | |
664 | space -= retval; | |
665 | } else { | |
666 | if (!space) | |
667 | break; | |
668 | tty_put_char(tty, c); | |
669 | space -= 1; | |
670 | } | |
a88a69c9 JP |
671 | cp += 1; |
672 | nr -= 1; | |
673 | } | |
674 | ||
675 | /* When end of circular buffer reached, wrap around */ | |
676 | if (cp >= buf_end) | |
677 | cp -= N_TTY_BUF_SIZE; | |
678 | } | |
679 | ||
680 | if (nr == 0) { | |
ba2e68ac JS |
681 | ldata->echo_pos = 0; |
682 | ldata->echo_cnt = 0; | |
53c5ee2c | 683 | ldata->echo_overrun = 0; |
a88a69c9 | 684 | } else { |
ba2e68ac JS |
685 | int num_processed = ldata->echo_cnt - nr; |
686 | ldata->echo_pos += num_processed; | |
687 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; | |
688 | ldata->echo_cnt = nr; | |
a88a69c9 | 689 | if (num_processed > 0) |
53c5ee2c | 690 | ldata->echo_overrun = 0; |
a88a69c9 JP |
691 | } |
692 | ||
bddc7152 JS |
693 | mutex_unlock(&ldata->echo_lock); |
694 | mutex_unlock(&ldata->output_lock); | |
a88a69c9 JP |
695 | |
696 | if (tty->ops->flush_chars) | |
697 | tty->ops->flush_chars(tty); | |
698 | } | |
699 | ||
700 | /** | |
701 | * add_echo_byte - add a byte to the echo buffer | |
702 | * @c: unicode byte to echo | |
57c94121 | 703 | * @ldata: n_tty data |
a88a69c9 JP |
704 | * |
705 | * Add a character or operation byte to the echo buffer. | |
706 | * | |
707 | * Should be called under the echo lock to protect the echo buffer. | |
708 | */ | |
709 | ||
57c94121 | 710 | static void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 JP |
711 | { |
712 | int new_byte_pos; | |
713 | ||
ba2e68ac | 714 | if (ldata->echo_cnt == N_TTY_BUF_SIZE) { |
a88a69c9 | 715 | /* Circular buffer is already at capacity */ |
ba2e68ac | 716 | new_byte_pos = ldata->echo_pos; |
a88a69c9 JP |
717 | |
718 | /* | |
719 | * Since the buffer start position needs to be advanced, | |
720 | * be sure to step by a whole operation byte group. | |
721 | */ | |
ba2e68ac JS |
722 | if (ldata->echo_buf[ldata->echo_pos] == ECHO_OP_START) { |
723 | if (ldata->echo_buf[(ldata->echo_pos + 1) & | |
a88a69c9 JP |
724 | (N_TTY_BUF_SIZE - 1)] == |
725 | ECHO_OP_ERASE_TAB) { | |
ba2e68ac JS |
726 | ldata->echo_pos += 3; |
727 | ldata->echo_cnt -= 2; | |
a88a69c9 | 728 | } else { |
ba2e68ac JS |
729 | ldata->echo_pos += 2; |
730 | ldata->echo_cnt -= 1; | |
a88a69c9 JP |
731 | } |
732 | } else { | |
ba2e68ac | 733 | ldata->echo_pos++; |
a88a69c9 | 734 | } |
ba2e68ac | 735 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; |
a88a69c9 | 736 | |
53c5ee2c | 737 | ldata->echo_overrun = 1; |
a88a69c9 | 738 | } else { |
ba2e68ac | 739 | new_byte_pos = ldata->echo_pos + ldata->echo_cnt; |
a88a69c9 | 740 | new_byte_pos &= N_TTY_BUF_SIZE - 1; |
ba2e68ac | 741 | ldata->echo_cnt++; |
a88a69c9 JP |
742 | } |
743 | ||
ba2e68ac | 744 | ldata->echo_buf[new_byte_pos] = c; |
a88a69c9 JP |
745 | } |
746 | ||
747 | /** | |
748 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 749 | * @ldata: n_tty data |
a88a69c9 JP |
750 | * |
751 | * Add an operation to the echo buffer to move back one column. | |
752 | * | |
753 | * Locking: echo_lock to protect the echo buffer | |
754 | */ | |
755 | ||
57c94121 | 756 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 757 | { |
bddc7152 | 758 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
759 | add_echo_byte(ECHO_OP_START, ldata); |
760 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
bddc7152 | 761 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
762 | } |
763 | ||
764 | /** | |
765 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 766 | * @ldata: n_tty data |
a88a69c9 JP |
767 | * |
768 | * Add an operation to the echo buffer to set the canon column | |
769 | * to the current column. | |
770 | * | |
771 | * Locking: echo_lock to protect the echo buffer | |
772 | */ | |
773 | ||
57c94121 | 774 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 775 | { |
bddc7152 | 776 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
777 | add_echo_byte(ECHO_OP_START, ldata); |
778 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
bddc7152 | 779 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
780 | } |
781 | ||
782 | /** | |
783 | * echo_erase_tab - add operation to erase a tab | |
784 | * @num_chars: number of character columns already used | |
785 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 786 | * @ldata: n_tty data |
a88a69c9 JP |
787 | * |
788 | * Add an operation to the echo buffer to erase a tab. | |
789 | * | |
790 | * Called by the eraser function, which knows how many character | |
791 | * columns have been used since either a previous tab or the start | |
792 | * of input. This information will be used later, along with | |
793 | * canon column (if applicable), to go back the correct number | |
794 | * of columns. | |
795 | * | |
796 | * Locking: echo_lock to protect the echo buffer | |
797 | */ | |
798 | ||
799 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 800 | struct n_tty_data *ldata) |
a88a69c9 | 801 | { |
bddc7152 | 802 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 803 | |
57c94121 JS |
804 | add_echo_byte(ECHO_OP_START, ldata); |
805 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
806 | |
807 | /* We only need to know this modulo 8 (tab spacing) */ | |
808 | num_chars &= 7; | |
809 | ||
810 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
811 | if (after_tab) | |
812 | num_chars |= 0x80; | |
300a6204 | 813 | |
57c94121 | 814 | add_echo_byte(num_chars, ldata); |
a88a69c9 | 815 | |
bddc7152 | 816 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
817 | } |
818 | ||
819 | /** | |
820 | * echo_char_raw - echo a character raw | |
821 | * @c: unicode byte to echo | |
822 | * @tty: terminal device | |
823 | * | |
824 | * Echo user input back onto the screen. This must be called only when | |
825 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
826 | * | |
827 | * This variant does not treat control characters specially. | |
828 | * | |
829 | * Locking: echo_lock to protect the echo buffer | |
830 | */ | |
831 | ||
57c94121 | 832 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 833 | { |
bddc7152 | 834 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 835 | if (c == ECHO_OP_START) { |
57c94121 JS |
836 | add_echo_byte(ECHO_OP_START, ldata); |
837 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 838 | } else { |
57c94121 | 839 | add_echo_byte(c, ldata); |
a88a69c9 | 840 | } |
bddc7152 | 841 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 | 842 | } |
1da177e4 | 843 | |
1da177e4 | 844 | /** |
a88a69c9 | 845 | * echo_char - echo a character |
1da177e4 LT |
846 | * @c: unicode byte to echo |
847 | * @tty: terminal device | |
848 | * | |
4edf1827 | 849 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 850 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 851 | * |
62b26358 JP |
852 | * This variant tags control characters to be echoed as "^X" |
853 | * (where X is the letter representing the control char). | |
a88a69c9 JP |
854 | * |
855 | * Locking: echo_lock to protect the echo buffer | |
1da177e4 LT |
856 | */ |
857 | ||
858 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
859 | { | |
bddc7152 JS |
860 | struct n_tty_data *ldata = tty->disc_data; |
861 | ||
862 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
863 | |
864 | if (c == ECHO_OP_START) { | |
57c94121 JS |
865 | add_echo_byte(ECHO_OP_START, ldata); |
866 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 867 | } else { |
62b26358 | 868 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
869 | add_echo_byte(ECHO_OP_START, ldata); |
870 | add_echo_byte(c, ldata); | |
a88a69c9 JP |
871 | } |
872 | ||
bddc7152 | 873 | mutex_unlock(&ldata->echo_lock); |
1da177e4 LT |
874 | } |
875 | ||
17b82060 | 876 | /** |
a88a69c9 | 877 | * finish_erasing - complete erase |
57c94121 | 878 | * @ldata: n_tty data |
17b82060 | 879 | */ |
a88a69c9 | 880 | |
57c94121 | 881 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 882 | { |
53c5ee2c | 883 | if (ldata->erasing) { |
57c94121 | 884 | echo_char_raw('/', ldata); |
53c5ee2c | 885 | ldata->erasing = 0; |
1da177e4 LT |
886 | } |
887 | } | |
888 | ||
889 | /** | |
890 | * eraser - handle erase function | |
891 | * @c: character input | |
892 | * @tty: terminal device | |
893 | * | |
3a4fa0a2 | 894 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
895 | * present in the stream from the driver layer. Handles the complexities |
896 | * of UTF-8 multibyte symbols. | |
17b82060 | 897 | * |
a88a69c9 | 898 | * Locking: read_lock for tty buffers |
1da177e4 | 899 | */ |
4edf1827 | 900 | |
1da177e4 LT |
901 | static void eraser(unsigned char c, struct tty_struct *tty) |
902 | { | |
53c5ee2c | 903 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
904 | enum { ERASE, WERASE, KILL } kill_type; |
905 | int head, seen_alnums, cnt; | |
906 | unsigned long flags; | |
907 | ||
17b82060 | 908 | /* FIXME: locking needed ? */ |
ba2e68ac | 909 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 910 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
911 | return; |
912 | } | |
913 | if (c == ERASE_CHAR(tty)) | |
914 | kill_type = ERASE; | |
915 | else if (c == WERASE_CHAR(tty)) | |
916 | kill_type = WERASE; | |
917 | else { | |
918 | if (!L_ECHO(tty)) { | |
98001214 | 919 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 920 | ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) & |
1da177e4 | 921 | (N_TTY_BUF_SIZE - 1)); |
ba2e68ac | 922 | ldata->read_head = ldata->canon_head; |
98001214 | 923 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
924 | return; |
925 | } | |
926 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
98001214 | 927 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 928 | ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) & |
1da177e4 | 929 | (N_TTY_BUF_SIZE - 1)); |
ba2e68ac | 930 | ldata->read_head = ldata->canon_head; |
98001214 | 931 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
57c94121 | 932 | finish_erasing(ldata); |
1da177e4 LT |
933 | echo_char(KILL_CHAR(tty), tty); |
934 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
935 | if (L_ECHOK(tty)) | |
57c94121 | 936 | echo_char_raw('\n', ldata); |
1da177e4 LT |
937 | return; |
938 | } | |
939 | kill_type = KILL; | |
940 | } | |
941 | ||
942 | seen_alnums = 0; | |
17b82060 | 943 | /* FIXME: Locking ?? */ |
ba2e68ac JS |
944 | while (ldata->read_head != ldata->canon_head) { |
945 | head = ldata->read_head; | |
1da177e4 LT |
946 | |
947 | /* erase a single possibly multibyte character */ | |
948 | do { | |
949 | head = (head - 1) & (N_TTY_BUF_SIZE-1); | |
ba2e68ac JS |
950 | c = ldata->read_buf[head]; |
951 | } while (is_continuation(c, tty) && head != ldata->canon_head); | |
1da177e4 LT |
952 | |
953 | /* do not partially erase */ | |
954 | if (is_continuation(c, tty)) | |
955 | break; | |
956 | ||
957 | if (kill_type == WERASE) { | |
958 | /* Equivalent to BSD's ALTWERASE. */ | |
959 | if (isalnum(c) || c == '_') | |
960 | seen_alnums++; | |
961 | else if (seen_alnums) | |
962 | break; | |
963 | } | |
ba2e68ac | 964 | cnt = (ldata->read_head - head) & (N_TTY_BUF_SIZE-1); |
98001214 | 965 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac JS |
966 | ldata->read_head = head; |
967 | ldata->read_cnt -= cnt; | |
98001214 | 968 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
969 | if (L_ECHO(tty)) { |
970 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 971 | if (!ldata->erasing) { |
57c94121 | 972 | echo_char_raw('\\', ldata); |
53c5ee2c | 973 | ldata->erasing = 1; |
1da177e4 LT |
974 | } |
975 | /* if cnt > 1, output a multi-byte character */ | |
976 | echo_char(c, tty); | |
977 | while (--cnt > 0) { | |
978 | head = (head+1) & (N_TTY_BUF_SIZE-1); | |
57c94121 JS |
979 | echo_char_raw(ldata->read_buf[head], |
980 | ldata); | |
981 | echo_move_back_col(ldata); | |
1da177e4 LT |
982 | } |
983 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
984 | echo_char(ERASE_CHAR(tty), tty); | |
985 | } else if (c == '\t') { | |
a88a69c9 JP |
986 | unsigned int num_chars = 0; |
987 | int after_tab = 0; | |
ba2e68ac | 988 | unsigned long tail = ldata->read_head; |
a88a69c9 JP |
989 | |
990 | /* | |
991 | * Count the columns used for characters | |
992 | * since the start of input or after a | |
993 | * previous tab. | |
994 | * This info is used to go back the correct | |
995 | * number of columns. | |
996 | */ | |
ba2e68ac | 997 | while (tail != ldata->canon_head) { |
a88a69c9 | 998 | tail = (tail-1) & (N_TTY_BUF_SIZE-1); |
ba2e68ac | 999 | c = ldata->read_buf[tail]; |
a88a69c9 JP |
1000 | if (c == '\t') { |
1001 | after_tab = 1; | |
1002 | break; | |
300a6204 | 1003 | } else if (iscntrl(c)) { |
1da177e4 | 1004 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1005 | num_chars += 2; |
1006 | } else if (!is_continuation(c, tty)) { | |
1007 | num_chars++; | |
1008 | } | |
1da177e4 | 1009 | } |
57c94121 | 1010 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1011 | } else { |
1012 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1013 | echo_char_raw('\b', ldata); |
1014 | echo_char_raw(' ', ldata); | |
1015 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1016 | } |
1017 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1018 | echo_char_raw('\b', ldata); |
1019 | echo_char_raw(' ', ldata); | |
1020 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1021 | } |
1022 | } | |
1023 | } | |
1024 | if (kill_type == ERASE) | |
1025 | break; | |
1026 | } | |
ba2e68ac | 1027 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1028 | finish_erasing(ldata); |
1da177e4 LT |
1029 | } |
1030 | ||
1031 | /** | |
1032 | * isig - handle the ISIG optio | |
1033 | * @sig: signal | |
1034 | * @tty: terminal | |
1035 | * @flush: force flush | |
1036 | * | |
1037 | * Called when a signal is being sent due to terminal input. This | |
1038 | * may caus terminal flushing to take place according to the termios | |
1039 | * settings and character used. Called from the driver receive_buf | |
1040 | * path so serialized. | |
17b82060 AC |
1041 | * |
1042 | * Locking: ctrl_lock, read_lock (both via flush buffer) | |
1da177e4 | 1043 | */ |
4edf1827 | 1044 | |
1da177e4 LT |
1045 | static inline void isig(int sig, struct tty_struct *tty, int flush) |
1046 | { | |
ab521dc0 EB |
1047 | if (tty->pgrp) |
1048 | kill_pgrp(tty->pgrp, sig, 1); | |
1da177e4 LT |
1049 | if (flush || !L_NOFLSH(tty)) { |
1050 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1051 | tty_driver_flush_buffer(tty); |
1da177e4 LT |
1052 | } |
1053 | } | |
1054 | ||
1055 | /** | |
1056 | * n_tty_receive_break - handle break | |
1057 | * @tty: terminal | |
1058 | * | |
1059 | * An RS232 break event has been hit in the incoming bitstream. This | |
1060 | * can cause a variety of events depending upon the termios settings. | |
1061 | * | |
1062 | * Called from the receive_buf path so single threaded. | |
1063 | */ | |
4edf1827 | 1064 | |
1da177e4 LT |
1065 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1066 | { | |
57c94121 JS |
1067 | struct n_tty_data *ldata = tty->disc_data; |
1068 | ||
1da177e4 LT |
1069 | if (I_IGNBRK(tty)) |
1070 | return; | |
1071 | if (I_BRKINT(tty)) { | |
1072 | isig(SIGINT, tty, 1); | |
1073 | return; | |
1074 | } | |
1075 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1076 | put_tty_queue('\377', ldata); |
1077 | put_tty_queue('\0', ldata); | |
1da177e4 | 1078 | } |
57c94121 | 1079 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1080 | wake_up_interruptible(&tty->read_wait); |
1081 | } | |
1082 | ||
1083 | /** | |
1084 | * n_tty_receive_overrun - handle overrun reporting | |
1085 | * @tty: terminal | |
1086 | * | |
1087 | * Data arrived faster than we could process it. While the tty | |
1088 | * driver has flagged this the bits that were missed are gone | |
1089 | * forever. | |
1090 | * | |
1091 | * Called from the receive_buf path so single threaded. Does not | |
1092 | * need locking as num_overrun and overrun_time are function | |
1093 | * private. | |
1094 | */ | |
4edf1827 | 1095 | |
1da177e4 LT |
1096 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1097 | { | |
53c5ee2c | 1098 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1099 | char buf[64]; |
1100 | ||
53c5ee2c JS |
1101 | ldata->num_overrun++; |
1102 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1103 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1104 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1105 | tty_name(tty, buf), | |
53c5ee2c JS |
1106 | ldata->num_overrun); |
1107 | ldata->overrun_time = jiffies; | |
1108 | ldata->num_overrun = 0; | |
1da177e4 LT |
1109 | } |
1110 | } | |
1111 | ||
1112 | /** | |
1113 | * n_tty_receive_parity_error - error notifier | |
1114 | * @tty: terminal device | |
1115 | * @c: character | |
1116 | * | |
1117 | * Process a parity error and queue the right data to indicate | |
3a4fa0a2 | 1118 | * the error case if necessary. Locking as per n_tty_receive_buf. |
1da177e4 LT |
1119 | */ |
1120 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1121 | unsigned char c) | |
1122 | { | |
57c94121 JS |
1123 | struct n_tty_data *ldata = tty->disc_data; |
1124 | ||
4edf1827 | 1125 | if (I_IGNPAR(tty)) |
1da177e4 | 1126 | return; |
1da177e4 | 1127 | if (I_PARMRK(tty)) { |
57c94121 JS |
1128 | put_tty_queue('\377', ldata); |
1129 | put_tty_queue('\0', ldata); | |
1130 | put_tty_queue(c, ldata); | |
1da177e4 | 1131 | } else if (I_INPCK(tty)) |
57c94121 | 1132 | put_tty_queue('\0', ldata); |
1da177e4 | 1133 | else |
57c94121 | 1134 | put_tty_queue(c, ldata); |
1da177e4 LT |
1135 | wake_up_interruptible(&tty->read_wait); |
1136 | } | |
1137 | ||
1138 | /** | |
1139 | * n_tty_receive_char - perform processing | |
1140 | * @tty: terminal device | |
1141 | * @c: character | |
1142 | * | |
1143 | * Process an individual character of input received from the driver. | |
4edf1827 | 1144 | * This is serialized with respect to itself by the rules for the |
1da177e4 LT |
1145 | * driver above. |
1146 | */ | |
1147 | ||
1148 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1149 | { | |
53c5ee2c | 1150 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1151 | unsigned long flags; |
acc71bba | 1152 | int parmrk; |
1da177e4 | 1153 | |
53c5ee2c | 1154 | if (ldata->raw) { |
57c94121 | 1155 | put_tty_queue(c, ldata); |
1da177e4 LT |
1156 | return; |
1157 | } | |
4edf1827 | 1158 | |
1da177e4 LT |
1159 | if (I_ISTRIP(tty)) |
1160 | c &= 0x7f; | |
1161 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1162 | c = tolower(c); |
1da177e4 | 1163 | |
26df6d13 | 1164 | if (L_EXTPROC(tty)) { |
57c94121 | 1165 | put_tty_queue(c, ldata); |
26df6d13 | 1166 | return; |
1167 | } | |
1168 | ||
54d2a37e | 1169 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1170 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1171 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1172 | start_tty(tty); |
a88a69c9 JP |
1173 | process_echoes(tty); |
1174 | } | |
54d2a37e | 1175 | |
1da177e4 LT |
1176 | if (tty->closing) { |
1177 | if (I_IXON(tty)) { | |
a88a69c9 | 1178 | if (c == START_CHAR(tty)) { |
1da177e4 | 1179 | start_tty(tty); |
a88a69c9 | 1180 | process_echoes(tty); |
300a6204 | 1181 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1182 | stop_tty(tty); |
1183 | } | |
1184 | return; | |
1185 | } | |
1186 | ||
1187 | /* | |
1188 | * If the previous character was LNEXT, or we know that this | |
1189 | * character is not one of the characters that we'll have to | |
1190 | * handle specially, do shortcut processing to speed things | |
1191 | * up. | |
1192 | */ | |
3fe780b3 | 1193 | if (!test_bit(c, ldata->process_char_map) || ldata->lnext) { |
53c5ee2c | 1194 | ldata->lnext = 0; |
acc71bba | 1195 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ba2e68ac | 1196 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1197 | /* beep if no space */ |
7e94b1d9 JP |
1198 | if (L_ECHO(tty)) |
1199 | process_output('\a', tty); | |
acc71bba JP |
1200 | return; |
1201 | } | |
1202 | if (L_ECHO(tty)) { | |
57c94121 | 1203 | finish_erasing(ldata); |
1da177e4 | 1204 | /* Record the column of first canon char. */ |
ba2e68ac | 1205 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1206 | echo_set_canon_col(ldata); |
1da177e4 | 1207 | echo_char(c, tty); |
a88a69c9 | 1208 | process_echoes(tty); |
1da177e4 | 1209 | } |
acc71bba | 1210 | if (parmrk) |
57c94121 JS |
1211 | put_tty_queue(c, ldata); |
1212 | put_tty_queue(c, ldata); | |
1da177e4 LT |
1213 | return; |
1214 | } | |
4edf1827 | 1215 | |
1da177e4 LT |
1216 | if (I_IXON(tty)) { |
1217 | if (c == START_CHAR(tty)) { | |
1218 | start_tty(tty); | |
a88a69c9 | 1219 | process_echoes(tty); |
1da177e4 LT |
1220 | return; |
1221 | } | |
1222 | if (c == STOP_CHAR(tty)) { | |
1223 | stop_tty(tty); | |
1224 | return; | |
1225 | } | |
1226 | } | |
575537b3 | 1227 | |
1da177e4 LT |
1228 | if (L_ISIG(tty)) { |
1229 | int signal; | |
1230 | signal = SIGINT; | |
1231 | if (c == INTR_CHAR(tty)) | |
1232 | goto send_signal; | |
1233 | signal = SIGQUIT; | |
1234 | if (c == QUIT_CHAR(tty)) | |
1235 | goto send_signal; | |
1236 | signal = SIGTSTP; | |
1237 | if (c == SUSP_CHAR(tty)) { | |
1238 | send_signal: | |
ec5b1157 | 1239 | /* |
ec5b1157 JP |
1240 | * Note that we do not use isig() here because we want |
1241 | * the order to be: | |
1242 | * 1) flush, 2) echo, 3) signal | |
1243 | */ | |
1244 | if (!L_NOFLSH(tty)) { | |
1245 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1246 | tty_driver_flush_buffer(tty); |
ec5b1157 | 1247 | } |
a88a69c9 JP |
1248 | if (I_IXON(tty)) |
1249 | start_tty(tty); | |
1250 | if (L_ECHO(tty)) { | |
ec5b1157 | 1251 | echo_char(c, tty); |
a88a69c9 JP |
1252 | process_echoes(tty); |
1253 | } | |
ec5b1157 JP |
1254 | if (tty->pgrp) |
1255 | kill_pgrp(tty->pgrp, signal, 1); | |
1da177e4 LT |
1256 | return; |
1257 | } | |
1258 | } | |
575537b3 JP |
1259 | |
1260 | if (c == '\r') { | |
1261 | if (I_IGNCR(tty)) | |
1262 | return; | |
1263 | if (I_ICRNL(tty)) | |
1264 | c = '\n'; | |
1265 | } else if (c == '\n' && I_INLCR(tty)) | |
1266 | c = '\r'; | |
1267 | ||
53c5ee2c | 1268 | if (ldata->icanon) { |
1da177e4 LT |
1269 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1270 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1271 | eraser(c, tty); | |
a88a69c9 | 1272 | process_echoes(tty); |
1da177e4 LT |
1273 | return; |
1274 | } | |
1275 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1276 | ldata->lnext = 1; |
1da177e4 | 1277 | if (L_ECHO(tty)) { |
57c94121 | 1278 | finish_erasing(ldata); |
1da177e4 | 1279 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1280 | echo_char_raw('^', ldata); |
1281 | echo_char_raw('\b', ldata); | |
a88a69c9 | 1282 | process_echoes(tty); |
1da177e4 LT |
1283 | } |
1284 | } | |
1285 | return; | |
1286 | } | |
1287 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1288 | L_IEXTEN(tty)) { | |
ba2e68ac | 1289 | unsigned long tail = ldata->canon_head; |
1da177e4 | 1290 | |
57c94121 | 1291 | finish_erasing(ldata); |
1da177e4 | 1292 | echo_char(c, tty); |
57c94121 | 1293 | echo_char_raw('\n', ldata); |
ba2e68ac JS |
1294 | while (tail != ldata->read_head) { |
1295 | echo_char(ldata->read_buf[tail], tty); | |
1da177e4 LT |
1296 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); |
1297 | } | |
a88a69c9 | 1298 | process_echoes(tty); |
1da177e4 LT |
1299 | return; |
1300 | } | |
1301 | if (c == '\n') { | |
ba2e68ac | 1302 | if (ldata->read_cnt >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1303 | if (L_ECHO(tty)) |
1304 | process_output('\a', tty); | |
acc71bba JP |
1305 | return; |
1306 | } | |
1307 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
57c94121 | 1308 | echo_char_raw('\n', ldata); |
a88a69c9 | 1309 | process_echoes(tty); |
1da177e4 LT |
1310 | } |
1311 | goto handle_newline; | |
1312 | } | |
1313 | if (c == EOF_CHAR(tty)) { | |
ba2e68ac | 1314 | if (ldata->read_cnt >= N_TTY_BUF_SIZE) |
acc71bba | 1315 | return; |
ba2e68ac | 1316 | if (ldata->canon_head != ldata->read_head) |
4edf1827 | 1317 | set_bit(TTY_PUSH, &tty->flags); |
1da177e4 LT |
1318 | c = __DISABLED_CHAR; |
1319 | goto handle_newline; | |
1320 | } | |
1321 | if ((c == EOL_CHAR(tty)) || | |
1322 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1323 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1324 | ? 1 : 0; | |
ba2e68ac | 1325 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) { |
7e94b1d9 JP |
1326 | if (L_ECHO(tty)) |
1327 | process_output('\a', tty); | |
acc71bba JP |
1328 | return; |
1329 | } | |
1da177e4 LT |
1330 | /* |
1331 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1332 | */ | |
1333 | if (L_ECHO(tty)) { | |
1da177e4 | 1334 | /* Record the column of first canon char. */ |
ba2e68ac | 1335 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1336 | echo_set_canon_col(ldata); |
1da177e4 | 1337 | echo_char(c, tty); |
a88a69c9 | 1338 | process_echoes(tty); |
1da177e4 LT |
1339 | } |
1340 | /* | |
1341 | * XXX does PARMRK doubling happen for | |
1342 | * EOL_CHAR and EOL2_CHAR? | |
1343 | */ | |
acc71bba | 1344 | if (parmrk) |
57c94121 | 1345 | put_tty_queue(c, ldata); |
1da177e4 | 1346 | |
4edf1827 | 1347 | handle_newline: |
98001214 | 1348 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 1349 | set_bit(ldata->read_head, ldata->read_flags); |
57c94121 | 1350 | put_tty_queue_nolock(c, ldata); |
ba2e68ac JS |
1351 | ldata->canon_head = ldata->read_head; |
1352 | ldata->canon_data++; | |
98001214 | 1353 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1354 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1355 | if (waitqueue_active(&tty->read_wait)) | |
1356 | wake_up_interruptible(&tty->read_wait); | |
1357 | return; | |
1358 | } | |
1359 | } | |
4edf1827 | 1360 | |
acc71bba | 1361 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ba2e68ac | 1362 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1363 | /* beep if no space */ |
7e94b1d9 JP |
1364 | if (L_ECHO(tty)) |
1365 | process_output('\a', tty); | |
acc71bba JP |
1366 | return; |
1367 | } | |
1368 | if (L_ECHO(tty)) { | |
57c94121 | 1369 | finish_erasing(ldata); |
1da177e4 | 1370 | if (c == '\n') |
57c94121 | 1371 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1372 | else { |
1373 | /* Record the column of first canon char. */ | |
ba2e68ac | 1374 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1375 | echo_set_canon_col(ldata); |
1da177e4 LT |
1376 | echo_char(c, tty); |
1377 | } | |
a88a69c9 | 1378 | process_echoes(tty); |
1da177e4 LT |
1379 | } |
1380 | ||
acc71bba | 1381 | if (parmrk) |
57c94121 | 1382 | put_tty_queue(c, ldata); |
1da177e4 | 1383 | |
57c94121 | 1384 | put_tty_queue(c, ldata); |
4edf1827 | 1385 | } |
1da177e4 | 1386 | |
1da177e4 LT |
1387 | |
1388 | /** | |
1389 | * n_tty_write_wakeup - asynchronous I/O notifier | |
1390 | * @tty: tty device | |
1391 | * | |
1392 | * Required for the ptys, serial driver etc. since processes | |
1393 | * that attach themselves to the master and rely on ASYNC | |
1394 | * IO must be woken up | |
1395 | */ | |
1396 | ||
1397 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
1398 | { | |
ff8cb0fd | 1399 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) |
1da177e4 | 1400 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); |
1da177e4 LT |
1401 | } |
1402 | ||
1403 | /** | |
1404 | * n_tty_receive_buf - data receive | |
1405 | * @tty: terminal device | |
1406 | * @cp: buffer | |
1407 | * @fp: flag buffer | |
1408 | * @count: characters | |
1409 | * | |
1410 | * Called by the terminal driver when a block of characters has | |
1411 | * been received. This function must be called from soft contexts | |
1412 | * not from interrupt context. The driver is responsible for making | |
1413 | * calls one at a time and in order (or using flush_to_ldisc) | |
1414 | */ | |
4edf1827 | 1415 | |
55db4c64 LT |
1416 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1417 | char *fp, int count) | |
1da177e4 | 1418 | { |
53c5ee2c | 1419 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1420 | const unsigned char *p; |
1421 | char *f, flags = TTY_NORMAL; | |
1422 | int i; | |
1423 | char buf[64]; | |
1424 | unsigned long cpuflags; | |
1425 | ||
53c5ee2c | 1426 | if (ldata->real_raw) { |
98001214 | 1427 | raw_spin_lock_irqsave(&ldata->read_lock, cpuflags); |
ba2e68ac JS |
1428 | i = min(N_TTY_BUF_SIZE - ldata->read_cnt, |
1429 | N_TTY_BUF_SIZE - ldata->read_head); | |
1da177e4 | 1430 | i = min(count, i); |
ba2e68ac JS |
1431 | memcpy(ldata->read_buf + ldata->read_head, cp, i); |
1432 | ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1433 | ldata->read_cnt += i; | |
1da177e4 LT |
1434 | cp += i; |
1435 | count -= i; | |
1436 | ||
ba2e68ac JS |
1437 | i = min(N_TTY_BUF_SIZE - ldata->read_cnt, |
1438 | N_TTY_BUF_SIZE - ldata->read_head); | |
1da177e4 | 1439 | i = min(count, i); |
ba2e68ac JS |
1440 | memcpy(ldata->read_buf + ldata->read_head, cp, i); |
1441 | ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1442 | ldata->read_cnt += i; | |
98001214 | 1443 | raw_spin_unlock_irqrestore(&ldata->read_lock, cpuflags); |
1da177e4 | 1444 | } else { |
4edf1827 | 1445 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1446 | if (f) |
1447 | flags = *f++; | |
1448 | switch (flags) { | |
1449 | case TTY_NORMAL: | |
1450 | n_tty_receive_char(tty, *p); | |
1451 | break; | |
1452 | case TTY_BREAK: | |
1453 | n_tty_receive_break(tty); | |
1454 | break; | |
1455 | case TTY_PARITY: | |
1456 | case TTY_FRAME: | |
1457 | n_tty_receive_parity_error(tty, *p); | |
1458 | break; | |
1459 | case TTY_OVERRUN: | |
1460 | n_tty_receive_overrun(tty); | |
1461 | break; | |
1462 | default: | |
4edf1827 | 1463 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1464 | tty_name(tty, buf), flags); |
1465 | break; | |
1466 | } | |
1467 | } | |
f34d7a5b AC |
1468 | if (tty->ops->flush_chars) |
1469 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1470 | } |
1471 | ||
55db4c64 LT |
1472 | n_tty_set_room(tty); |
1473 | ||
ba2e68ac | 1474 | if ((!ldata->icanon && (ldata->read_cnt >= tty->minimum_to_wake)) || |
26df6d13 | 1475 | L_EXTPROC(tty)) { |
1da177e4 LT |
1476 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1477 | if (waitqueue_active(&tty->read_wait)) | |
1478 | wake_up_interruptible(&tty->read_wait); | |
1479 | } | |
1480 | ||
1481 | /* | |
1482 | * Check the remaining room for the input canonicalization | |
1483 | * mode. We don't want to throttle the driver if we're in | |
1484 | * canonical mode and don't have a newline yet! | |
1485 | */ | |
55db4c64 | 1486 | if (tty->receive_room < TTY_THRESHOLD_THROTTLE) |
39c2e60f | 1487 | tty_throttle(tty); |
0a44ab41 AC |
1488 | |
1489 | /* FIXME: there is a tiny race here if the receive room check runs | |
1490 | before the other work executes and empties the buffer (upping | |
1491 | the receiving room and unthrottling. We then throttle and get | |
1492 | stuck. This has been observed and traced down by Vincent Pillet/ | |
1493 | We need to address this when we sort out out the rx path locking */ | |
1da177e4 LT |
1494 | } |
1495 | ||
1496 | int is_ignored(int sig) | |
1497 | { | |
1498 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1499 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1500 | } |
1501 | ||
1502 | /** | |
1503 | * n_tty_set_termios - termios data changed | |
1504 | * @tty: terminal | |
1505 | * @old: previous data | |
1506 | * | |
1507 | * Called by the tty layer when the user changes termios flags so | |
1508 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1509 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1510 | * guaranteed that this function will not be re-entered or in progress |
1511 | * when the ldisc is closed. | |
17b82060 AC |
1512 | * |
1513 | * Locking: Caller holds tty->termios_mutex | |
1da177e4 | 1514 | */ |
4edf1827 AC |
1515 | |
1516 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1517 | { |
53c5ee2c | 1518 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1519 | int canon_change = 1; |
47afa7a5 AC |
1520 | |
1521 | if (old) | |
adc8d746 | 1522 | canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON; |
47afa7a5 | 1523 | if (canon_change) { |
3fe780b3 | 1524 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
ba2e68ac JS |
1525 | ldata->canon_head = ldata->read_tail; |
1526 | ldata->canon_data = 0; | |
53c5ee2c | 1527 | ldata->erasing = 0; |
47afa7a5 AC |
1528 | } |
1529 | ||
ba2e68ac | 1530 | if (canon_change && !L_ICANON(tty) && ldata->read_cnt) |
47afa7a5 | 1531 | wake_up_interruptible(&tty->read_wait); |
4edf1827 | 1532 | |
53c5ee2c | 1533 | ldata->icanon = (L_ICANON(tty) != 0); |
1da177e4 | 1534 | if (test_bit(TTY_HW_COOK_IN, &tty->flags)) { |
53c5ee2c JS |
1535 | ldata->raw = 1; |
1536 | ldata->real_raw = 1; | |
55db4c64 | 1537 | n_tty_set_room(tty); |
1da177e4 LT |
1538 | return; |
1539 | } | |
1540 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || | |
1541 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1542 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1543 | I_PARMRK(tty)) { | |
3fe780b3 | 1544 | bitmap_zero(ldata->process_char_map, 256); |
1da177e4 LT |
1545 | |
1546 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
3fe780b3 | 1547 | set_bit('\r', ldata->process_char_map); |
1da177e4 | 1548 | if (I_INLCR(tty)) |
3fe780b3 | 1549 | set_bit('\n', ldata->process_char_map); |
1da177e4 LT |
1550 | |
1551 | if (L_ICANON(tty)) { | |
3fe780b3 JS |
1552 | set_bit(ERASE_CHAR(tty), ldata->process_char_map); |
1553 | set_bit(KILL_CHAR(tty), ldata->process_char_map); | |
1554 | set_bit(EOF_CHAR(tty), ldata->process_char_map); | |
1555 | set_bit('\n', ldata->process_char_map); | |
1556 | set_bit(EOL_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1557 | if (L_IEXTEN(tty)) { |
1558 | set_bit(WERASE_CHAR(tty), | |
3fe780b3 | 1559 | ldata->process_char_map); |
1da177e4 | 1560 | set_bit(LNEXT_CHAR(tty), |
3fe780b3 | 1561 | ldata->process_char_map); |
1da177e4 | 1562 | set_bit(EOL2_CHAR(tty), |
3fe780b3 | 1563 | ldata->process_char_map); |
1da177e4 LT |
1564 | if (L_ECHO(tty)) |
1565 | set_bit(REPRINT_CHAR(tty), | |
3fe780b3 | 1566 | ldata->process_char_map); |
1da177e4 LT |
1567 | } |
1568 | } | |
1569 | if (I_IXON(tty)) { | |
3fe780b3 JS |
1570 | set_bit(START_CHAR(tty), ldata->process_char_map); |
1571 | set_bit(STOP_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1572 | } |
1573 | if (L_ISIG(tty)) { | |
3fe780b3 JS |
1574 | set_bit(INTR_CHAR(tty), ldata->process_char_map); |
1575 | set_bit(QUIT_CHAR(tty), ldata->process_char_map); | |
1576 | set_bit(SUSP_CHAR(tty), ldata->process_char_map); | |
1da177e4 | 1577 | } |
3fe780b3 | 1578 | clear_bit(__DISABLED_CHAR, ldata->process_char_map); |
53c5ee2c JS |
1579 | ldata->raw = 0; |
1580 | ldata->real_raw = 0; | |
1da177e4 | 1581 | } else { |
53c5ee2c | 1582 | ldata->raw = 1; |
1da177e4 LT |
1583 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1584 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1585 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1586 | ldata->real_raw = 1; |
1da177e4 | 1587 | else |
53c5ee2c | 1588 | ldata->real_raw = 0; |
1da177e4 | 1589 | } |
55db4c64 | 1590 | n_tty_set_room(tty); |
f34d7a5b AC |
1591 | /* The termios change make the tty ready for I/O */ |
1592 | wake_up_interruptible(&tty->write_wait); | |
1593 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1594 | } |
1595 | ||
1596 | /** | |
1597 | * n_tty_close - close the ldisc for this tty | |
1598 | * @tty: device | |
1599 | * | |
4edf1827 AC |
1600 | * Called from the terminal layer when this line discipline is |
1601 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1602 | * discipline change. The function will not be called while other |
1603 | * ldisc methods are in progress. | |
1604 | */ | |
4edf1827 | 1605 | |
1da177e4 LT |
1606 | static void n_tty_close(struct tty_struct *tty) |
1607 | { | |
70ece7a7 JS |
1608 | struct n_tty_data *ldata = tty->disc_data; |
1609 | ||
1da177e4 | 1610 | n_tty_flush_buffer(tty); |
ba2e68ac JS |
1611 | kfree(ldata->read_buf); |
1612 | kfree(ldata->echo_buf); | |
70ece7a7 | 1613 | kfree(ldata); |
70ece7a7 | 1614 | tty->disc_data = NULL; |
1da177e4 LT |
1615 | } |
1616 | ||
1617 | /** | |
1618 | * n_tty_open - open an ldisc | |
1619 | * @tty: terminal to open | |
1620 | * | |
4edf1827 | 1621 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1622 | * terminal device. Can sleep. Called serialized so that no |
1623 | * other events will occur in parallel. No further open will occur | |
1624 | * until a close. | |
1625 | */ | |
1626 | ||
1627 | static int n_tty_open(struct tty_struct *tty) | |
1628 | { | |
70ece7a7 JS |
1629 | struct n_tty_data *ldata; |
1630 | ||
1631 | ldata = kzalloc(sizeof(*ldata), GFP_KERNEL); | |
1632 | if (!ldata) | |
1633 | goto err; | |
1634 | ||
53c5ee2c | 1635 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1636 | mutex_init(&ldata->atomic_read_lock); |
1637 | mutex_init(&ldata->output_lock); | |
1638 | mutex_init(&ldata->echo_lock); | |
98001214 | 1639 | raw_spin_lock_init(&ldata->read_lock); |
53c5ee2c | 1640 | |
a88a69c9 | 1641 | /* These are ugly. Currently a malloc failure here can panic */ |
ba2e68ac JS |
1642 | ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1643 | ldata->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); | |
1644 | if (!ldata->read_buf || !ldata->echo_buf) | |
b91939f5 | 1645 | goto err_free_bufs; |
0b4068a1 | 1646 | |
70ece7a7 | 1647 | tty->disc_data = ldata; |
1da177e4 | 1648 | reset_buffer_flags(tty); |
7b292b4b | 1649 | tty_unthrottle(tty); |
53c5ee2c | 1650 | ldata->column = 0; |
1da177e4 LT |
1651 | n_tty_set_termios(tty, NULL); |
1652 | tty->minimum_to_wake = 1; | |
1653 | tty->closing = 0; | |
70ece7a7 | 1654 | |
1da177e4 | 1655 | return 0; |
b91939f5 | 1656 | err_free_bufs: |
ba2e68ac JS |
1657 | kfree(ldata->read_buf); |
1658 | kfree(ldata->echo_buf); | |
70ece7a7 JS |
1659 | kfree(ldata); |
1660 | err: | |
b91939f5 | 1661 | return -ENOMEM; |
1da177e4 LT |
1662 | } |
1663 | ||
1664 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1665 | { | |
53c5ee2c JS |
1666 | struct n_tty_data *ldata = tty->disc_data; |
1667 | ||
e043e42b | 1668 | tty_flush_to_ldisc(tty); |
53c5ee2c | 1669 | if (ldata->icanon && !L_EXTPROC(tty)) { |
ba2e68ac | 1670 | if (ldata->canon_data) |
1da177e4 | 1671 | return 1; |
ba2e68ac | 1672 | } else if (ldata->read_cnt >= (amt ? amt : 1)) |
1da177e4 LT |
1673 | return 1; |
1674 | ||
1675 | return 0; | |
1676 | } | |
1677 | ||
1678 | /** | |
bbd20759 | 1679 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1680 | * @tty: terminal device |
1681 | * @b: user data | |
1682 | * @nr: size of data | |
1683 | * | |
11a96d18 | 1684 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1685 | * ICANON is off; it copies characters straight from the tty queue to |
1686 | * user space directly. It can be profitably called twice; once to | |
1687 | * drain the space from the tail pointer to the (physical) end of the | |
1688 | * buffer, and once to drain the space from the (physical) beginning of | |
1689 | * the buffer to head pointer. | |
1690 | * | |
bddc7152 | 1691 | * Called under the ldata->atomic_read_lock sem |
1da177e4 LT |
1692 | * |
1693 | */ | |
4edf1827 | 1694 | |
33f0f88f | 1695 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1696 | unsigned char __user **b, |
1697 | size_t *nr) | |
1698 | ||
1699 | { | |
53c5ee2c | 1700 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1701 | int retval; |
1702 | size_t n; | |
1703 | unsigned long flags; | |
3fa10cc8 | 1704 | bool is_eof; |
1da177e4 LT |
1705 | |
1706 | retval = 0; | |
98001214 | 1707 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 1708 | n = min(ldata->read_cnt, N_TTY_BUF_SIZE - ldata->read_tail); |
1da177e4 | 1709 | n = min(*nr, n); |
98001214 | 1710 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 | 1711 | if (n) { |
ba2e68ac | 1712 | retval = copy_to_user(*b, &ldata->read_buf[ldata->read_tail], n); |
1da177e4 | 1713 | n -= retval; |
3fa10cc8 | 1714 | is_eof = n == 1 && |
ba2e68ac JS |
1715 | ldata->read_buf[ldata->read_tail] == EOF_CHAR(tty); |
1716 | tty_audit_add_data(tty, &ldata->read_buf[ldata->read_tail], n, | |
53c5ee2c | 1717 | ldata->icanon); |
98001214 | 1718 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac JS |
1719 | ldata->read_tail = (ldata->read_tail + n) & (N_TTY_BUF_SIZE-1); |
1720 | ldata->read_cnt -= n; | |
26df6d13 | 1721 | /* Turn single EOF into zero-length read */ |
ba2e68ac | 1722 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !ldata->read_cnt) |
3fa10cc8 | 1723 | n = 0; |
98001214 | 1724 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1725 | *b += n; |
1726 | *nr -= n; | |
1727 | } | |
1728 | return retval; | |
1729 | } | |
1730 | ||
cc4191dc | 1731 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1732 | size_t, loff_t *); |
1da177e4 LT |
1733 | |
1734 | /** | |
1735 | * job_control - check job control | |
1736 | * @tty: tty | |
1737 | * @file: file handle | |
1738 | * | |
1739 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1740 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1741 | * error code if action should be taken. |
04f378b1 AC |
1742 | * |
1743 | * FIXME: | |
1744 | * Locking: None - redirected write test is safe, testing | |
1745 | * current->signal should possibly lock current->sighand | |
1746 | * pgrp locking ? | |
1da177e4 | 1747 | */ |
4edf1827 | 1748 | |
1da177e4 LT |
1749 | static int job_control(struct tty_struct *tty, struct file *file) |
1750 | { | |
1751 | /* Job control check -- must be done at start and after | |
1752 | every sleep (POSIX.1 7.1.1.4). */ | |
1753 | /* NOTE: not yet done after every sleep pending a thorough | |
1754 | check of the logic of this change. -- jlc */ | |
1755 | /* don't stop on /dev/console */ | |
1756 | if (file->f_op->write != redirected_tty_write && | |
1757 | current->signal->tty == tty) { | |
ab521dc0 | 1758 | if (!tty->pgrp) |
11a96d18 | 1759 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); |
ab521dc0 | 1760 | else if (task_pgrp(current) != tty->pgrp) { |
1da177e4 | 1761 | if (is_ignored(SIGTTIN) || |
3e7cd6c4 | 1762 | is_current_pgrp_orphaned()) |
1da177e4 | 1763 | return -EIO; |
ab521dc0 | 1764 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); |
040b6362 | 1765 | set_thread_flag(TIF_SIGPENDING); |
1da177e4 LT |
1766 | return -ERESTARTSYS; |
1767 | } | |
1768 | } | |
1769 | return 0; | |
1770 | } | |
4edf1827 | 1771 | |
1da177e4 LT |
1772 | |
1773 | /** | |
11a96d18 | 1774 | * n_tty_read - read function for tty |
1da177e4 LT |
1775 | * @tty: tty device |
1776 | * @file: file object | |
1777 | * @buf: userspace buffer pointer | |
1778 | * @nr: size of I/O | |
1779 | * | |
1780 | * Perform reads for the line discipline. We are guaranteed that the | |
1781 | * line discipline will not be closed under us but we may get multiple | |
1782 | * parallel readers and must handle this ourselves. We may also get | |
1783 | * a hangup. Always called in user context, may sleep. | |
1784 | * | |
1785 | * This code must be sure never to sleep through a hangup. | |
1786 | */ | |
4edf1827 | 1787 | |
11a96d18 | 1788 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1789 | unsigned char __user *buf, size_t nr) |
1790 | { | |
53c5ee2c | 1791 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1792 | unsigned char __user *b = buf; |
1793 | DECLARE_WAITQUEUE(wait, current); | |
1794 | int c; | |
1795 | int minimum, time; | |
1796 | ssize_t retval = 0; | |
1797 | ssize_t size; | |
1798 | long timeout; | |
1799 | unsigned long flags; | |
04f378b1 | 1800 | int packet; |
1da177e4 LT |
1801 | |
1802 | do_it_again: | |
1da177e4 | 1803 | c = job_control(tty, file); |
4edf1827 | 1804 | if (c < 0) |
1da177e4 | 1805 | return c; |
4edf1827 | 1806 | |
1da177e4 LT |
1807 | minimum = time = 0; |
1808 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 1809 | if (!ldata->icanon) { |
1da177e4 LT |
1810 | time = (HZ / 10) * TIME_CHAR(tty); |
1811 | minimum = MIN_CHAR(tty); | |
1812 | if (minimum) { | |
1813 | if (time) | |
1814 | tty->minimum_to_wake = 1; | |
1815 | else if (!waitqueue_active(&tty->read_wait) || | |
1816 | (tty->minimum_to_wake > minimum)) | |
1817 | tty->minimum_to_wake = minimum; | |
1818 | } else { | |
1819 | timeout = 0; | |
1820 | if (time) { | |
1821 | timeout = time; | |
1822 | time = 0; | |
1823 | } | |
1824 | tty->minimum_to_wake = minimum = 1; | |
1825 | } | |
1826 | } | |
1827 | ||
1828 | /* | |
1829 | * Internal serialization of reads. | |
1830 | */ | |
1831 | if (file->f_flags & O_NONBLOCK) { | |
bddc7152 | 1832 | if (!mutex_trylock(&ldata->atomic_read_lock)) |
1da177e4 | 1833 | return -EAGAIN; |
4edf1827 | 1834 | } else { |
bddc7152 | 1835 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) |
1da177e4 LT |
1836 | return -ERESTARTSYS; |
1837 | } | |
04f378b1 | 1838 | packet = tty->packet; |
1da177e4 LT |
1839 | |
1840 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
1841 | while (nr) { |
1842 | /* First test for status change. */ | |
04f378b1 | 1843 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
1844 | unsigned char cs; |
1845 | if (b != buf) | |
1846 | break; | |
04f378b1 | 1847 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
1848 | cs = tty->link->ctrl_status; |
1849 | tty->link->ctrl_status = 0; | |
04f378b1 | 1850 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 1851 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
1852 | retval = -EFAULT; |
1853 | b--; | |
1854 | break; | |
1855 | } | |
1856 | nr--; | |
1857 | break; | |
1858 | } | |
1859 | /* This statement must be first before checking for input | |
1860 | so that any interrupt will set the state back to | |
1861 | TASK_RUNNING. */ | |
1862 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 1863 | |
1da177e4 LT |
1864 | if (((minimum - (b - buf)) < tty->minimum_to_wake) && |
1865 | ((minimum - (b - buf)) >= 1)) | |
1866 | tty->minimum_to_wake = (minimum - (b - buf)); | |
4edf1827 | 1867 | |
1da177e4 LT |
1868 | if (!input_available_p(tty, 0)) { |
1869 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
1870 | retval = -EIO; | |
1871 | break; | |
1872 | } | |
1873 | if (tty_hung_up_p(file)) | |
1874 | break; | |
1875 | if (!timeout) | |
1876 | break; | |
1877 | if (file->f_flags & O_NONBLOCK) { | |
1878 | retval = -EAGAIN; | |
1879 | break; | |
1880 | } | |
1881 | if (signal_pending(current)) { | |
1882 | retval = -ERESTARTSYS; | |
1883 | break; | |
1884 | } | |
55db4c64 LT |
1885 | /* FIXME: does n_tty_set_room need locking ? */ |
1886 | n_tty_set_room(tty); | |
1da177e4 | 1887 | timeout = schedule_timeout(timeout); |
1da177e4 LT |
1888 | continue; |
1889 | } | |
1890 | __set_current_state(TASK_RUNNING); | |
1891 | ||
1892 | /* Deal with packet mode. */ | |
04f378b1 | 1893 | if (packet && b == buf) { |
522ed776 | 1894 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
1895 | retval = -EFAULT; |
1896 | b--; | |
1897 | break; | |
1898 | } | |
1899 | nr--; | |
1900 | } | |
1901 | ||
53c5ee2c | 1902 | if (ldata->icanon && !L_EXTPROC(tty)) { |
1da177e4 | 1903 | /* N.B. avoid overrun if nr == 0 */ |
98001214 | 1904 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 1905 | while (nr && ldata->read_cnt) { |
4edf1827 | 1906 | int eol; |
1da177e4 | 1907 | |
ba2e68ac | 1908 | eol = test_and_clear_bit(ldata->read_tail, |
3fe780b3 | 1909 | ldata->read_flags); |
ba2e68ac JS |
1910 | c = ldata->read_buf[ldata->read_tail]; |
1911 | ldata->read_tail = ((ldata->read_tail+1) & | |
1da177e4 | 1912 | (N_TTY_BUF_SIZE-1)); |
ba2e68ac | 1913 | ldata->read_cnt--; |
1da177e4 LT |
1914 | if (eol) { |
1915 | /* this test should be redundant: | |
1916 | * we shouldn't be reading data if | |
1917 | * canon_data is 0 | |
1918 | */ | |
ba2e68ac JS |
1919 | if (--ldata->canon_data < 0) |
1920 | ldata->canon_data = 0; | |
1da177e4 | 1921 | } |
98001214 | 1922 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1923 | |
1924 | if (!eol || (c != __DISABLED_CHAR)) { | |
522ed776 | 1925 | if (tty_put_user(tty, c, b++)) { |
1da177e4 LT |
1926 | retval = -EFAULT; |
1927 | b--; | |
98001214 | 1928 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
1da177e4 LT |
1929 | break; |
1930 | } | |
1931 | nr--; | |
1932 | } | |
522ed776 MT |
1933 | if (eol) { |
1934 | tty_audit_push(tty); | |
98001214 | 1935 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
1da177e4 | 1936 | break; |
522ed776 | 1937 | } |
98001214 | 1938 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
1da177e4 | 1939 | } |
98001214 | 1940 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1941 | if (retval) |
1942 | break; | |
1943 | } else { | |
1944 | int uncopied; | |
04f378b1 AC |
1945 | /* The copy function takes the read lock and handles |
1946 | locking internally for this case */ | |
1da177e4 LT |
1947 | uncopied = copy_from_read_buf(tty, &b, &nr); |
1948 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
1949 | if (uncopied) { | |
1950 | retval = -EFAULT; | |
1951 | break; | |
1952 | } | |
1953 | } | |
1954 | ||
1955 | /* If there is enough space in the read buffer now, let the | |
1956 | * low-level driver know. We use n_tty_chars_in_buffer() to | |
1957 | * check the buffer, as it now knows about canonical mode. | |
1958 | * Otherwise, if the driver is throttled and the line is | |
1959 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
1960 | * we won't get any more characters. | |
1961 | */ | |
55db4c64 LT |
1962 | if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) { |
1963 | n_tty_set_room(tty); | |
1da177e4 | 1964 | check_unthrottle(tty); |
55db4c64 | 1965 | } |
1da177e4 LT |
1966 | |
1967 | if (b - buf >= minimum) | |
1968 | break; | |
1969 | if (time) | |
1970 | timeout = time; | |
1971 | } | |
bddc7152 | 1972 | mutex_unlock(&ldata->atomic_read_lock); |
1da177e4 LT |
1973 | remove_wait_queue(&tty->read_wait, &wait); |
1974 | ||
1975 | if (!waitqueue_active(&tty->read_wait)) | |
1976 | tty->minimum_to_wake = minimum; | |
1977 | ||
1978 | __set_current_state(TASK_RUNNING); | |
1979 | size = b - buf; | |
1980 | if (size) { | |
1981 | retval = size; | |
1982 | if (nr) | |
4edf1827 | 1983 | clear_bit(TTY_PUSH, &tty->flags); |
1da177e4 | 1984 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) |
bbd20759 | 1985 | goto do_it_again; |
1da177e4 | 1986 | |
55db4c64 | 1987 | n_tty_set_room(tty); |
1da177e4 LT |
1988 | return retval; |
1989 | } | |
1990 | ||
1991 | /** | |
11a96d18 | 1992 | * n_tty_write - write function for tty |
1da177e4 LT |
1993 | * @tty: tty device |
1994 | * @file: file object | |
1995 | * @buf: userspace buffer pointer | |
1996 | * @nr: size of I/O | |
1997 | * | |
a88a69c9 | 1998 | * Write function of the terminal device. This is serialized with |
1da177e4 | 1999 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2000 | * and other such events. Since the receive code will echo characters, |
2001 | * thus calling driver write methods, the output_lock is used in | |
2002 | * the output processing functions called here as well as in the | |
2003 | * echo processing function to protect the column state and space | |
2004 | * left in the buffer. | |
1da177e4 LT |
2005 | * |
2006 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2007 | * |
2008 | * Locking: output_lock to protect column state and space left | |
2009 | * (note that the process_output*() functions take this | |
2010 | * lock themselves) | |
1da177e4 | 2011 | */ |
4edf1827 | 2012 | |
11a96d18 | 2013 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2014 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2015 | { |
2016 | const unsigned char *b = buf; | |
2017 | DECLARE_WAITQUEUE(wait, current); | |
2018 | int c; | |
2019 | ssize_t retval = 0; | |
2020 | ||
2021 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2022 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2023 | retval = tty_check_change(tty); | |
2024 | if (retval) | |
2025 | return retval; | |
2026 | } | |
2027 | ||
a88a69c9 JP |
2028 | /* Write out any echoed characters that are still pending */ |
2029 | process_echoes(tty); | |
300a6204 | 2030 | |
1da177e4 LT |
2031 | add_wait_queue(&tty->write_wait, &wait); |
2032 | while (1) { | |
2033 | set_current_state(TASK_INTERRUPTIBLE); | |
2034 | if (signal_pending(current)) { | |
2035 | retval = -ERESTARTSYS; | |
2036 | break; | |
2037 | } | |
2038 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2039 | retval = -EIO; | |
2040 | break; | |
2041 | } | |
2042 | if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
2043 | while (nr > 0) { | |
a88a69c9 | 2044 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2045 | if (num < 0) { |
2046 | if (num == -EAGAIN) | |
2047 | break; | |
2048 | retval = num; | |
2049 | goto break_out; | |
2050 | } | |
2051 | b += num; | |
2052 | nr -= num; | |
2053 | if (nr == 0) | |
2054 | break; | |
2055 | c = *b; | |
a88a69c9 | 2056 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2057 | break; |
2058 | b++; nr--; | |
2059 | } | |
f34d7a5b AC |
2060 | if (tty->ops->flush_chars) |
2061 | tty->ops->flush_chars(tty); | |
1da177e4 | 2062 | } else { |
d6afe27b | 2063 | while (nr > 0) { |
f34d7a5b | 2064 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
2065 | if (c < 0) { |
2066 | retval = c; | |
2067 | goto break_out; | |
2068 | } | |
2069 | if (!c) | |
2070 | break; | |
2071 | b += c; | |
2072 | nr -= c; | |
1da177e4 | 2073 | } |
1da177e4 LT |
2074 | } |
2075 | if (!nr) | |
2076 | break; | |
2077 | if (file->f_flags & O_NONBLOCK) { | |
2078 | retval = -EAGAIN; | |
2079 | break; | |
2080 | } | |
2081 | schedule(); | |
2082 | } | |
2083 | break_out: | |
2084 | __set_current_state(TASK_RUNNING); | |
2085 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2086 | if (b - buf != nr && tty->fasync) |
2087 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
1da177e4 LT |
2088 | return (b - buf) ? b - buf : retval; |
2089 | } | |
2090 | ||
2091 | /** | |
11a96d18 | 2092 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2093 | * @tty: terminal device |
2094 | * @file: file accessing it | |
2095 | * @wait: poll table | |
2096 | * | |
2097 | * Called when the line discipline is asked to poll() for data or | |
2098 | * for special events. This code is not serialized with respect to | |
2099 | * other events save open/close. | |
2100 | * | |
2101 | * This code must be sure never to sleep through a hangup. | |
2102 | * Called without the kernel lock held - fine | |
1da177e4 | 2103 | */ |
4edf1827 | 2104 | |
11a96d18 | 2105 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2106 | poll_table *wait) |
1da177e4 LT |
2107 | { |
2108 | unsigned int mask = 0; | |
2109 | ||
2110 | poll_wait(file, &tty->read_wait, wait); | |
2111 | poll_wait(file, &tty->write_wait, wait); | |
2112 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2113 | mask |= POLLIN | POLLRDNORM; | |
2114 | if (tty->packet && tty->link->ctrl_status) | |
2115 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2116 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2117 | mask |= POLLHUP; | |
2118 | if (tty_hung_up_p(file)) | |
2119 | mask |= POLLHUP; | |
2120 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2121 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
2122 | tty->minimum_to_wake = MIN_CHAR(tty); | |
2123 | else | |
2124 | tty->minimum_to_wake = 1; | |
2125 | } | |
f34d7a5b AC |
2126 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2127 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2128 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2129 | mask |= POLLOUT | POLLWRNORM; |
2130 | return mask; | |
2131 | } | |
2132 | ||
57c94121 | 2133 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 AC |
2134 | { |
2135 | int nr, head, tail; | |
2136 | ||
ba2e68ac | 2137 | if (!ldata->canon_data) |
47afa7a5 | 2138 | return 0; |
ba2e68ac JS |
2139 | head = ldata->canon_head; |
2140 | tail = ldata->read_tail; | |
47afa7a5 AC |
2141 | nr = (head - tail) & (N_TTY_BUF_SIZE-1); |
2142 | /* Skip EOF-chars.. */ | |
2143 | while (head != tail) { | |
3fe780b3 | 2144 | if (test_bit(tail, ldata->read_flags) && |
ba2e68ac | 2145 | ldata->read_buf[tail] == __DISABLED_CHAR) |
47afa7a5 AC |
2146 | nr--; |
2147 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
2148 | } | |
2149 | return nr; | |
2150 | } | |
2151 | ||
2152 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2153 | unsigned int cmd, unsigned long arg) | |
2154 | { | |
ba2e68ac | 2155 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2156 | int retval; |
2157 | ||
2158 | switch (cmd) { | |
2159 | case TIOCOUTQ: | |
2160 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2161 | case TIOCINQ: | |
17b82060 | 2162 | /* FIXME: Locking */ |
ba2e68ac | 2163 | retval = ldata->read_cnt; |
47afa7a5 | 2164 | if (L_ICANON(tty)) |
57c94121 | 2165 | retval = inq_canon(ldata); |
47afa7a5 AC |
2166 | return put_user(retval, (unsigned int __user *) arg); |
2167 | default: | |
2168 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2169 | } | |
2170 | } | |
2171 | ||
a352def2 | 2172 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2173 | .magic = TTY_LDISC_MAGIC, |
2174 | .name = "n_tty", | |
2175 | .open = n_tty_open, | |
2176 | .close = n_tty_close, | |
2177 | .flush_buffer = n_tty_flush_buffer, | |
2178 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2179 | .read = n_tty_read, |
2180 | .write = n_tty_write, | |
e10cc1df PF |
2181 | .ioctl = n_tty_ioctl, |
2182 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2183 | .poll = n_tty_poll, |
e10cc1df PF |
2184 | .receive_buf = n_tty_receive_buf, |
2185 | .write_wakeup = n_tty_write_wakeup | |
1da177e4 | 2186 | }; |
572b9adb RG |
2187 | |
2188 | /** | |
2189 | * n_tty_inherit_ops - inherit N_TTY methods | |
2190 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2191 | * | |
593fb1ae | 2192 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2193 | * methods. |
2194 | */ | |
2195 | ||
2196 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2197 | { | |
2198 | *ops = tty_ldisc_N_TTY; | |
2199 | ops->owner = NULL; | |
2200 | ops->refcount = ops->flags = 0; | |
2201 | } | |
2202 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |