Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * n_tty.c --- implements the N_TTY line discipline. | |
4edf1827 | 3 | * |
1da177e4 LT |
4 | * This code used to be in tty_io.c, but things are getting hairy |
5 | * enough that it made sense to split things off. (The N_TTY | |
6 | * processing has changed so much that it's hardly recognizable, | |
7 | * anyway...) | |
8 | * | |
9 | * Note that the open routine for N_TTY is guaranteed never to return | |
10 | * an error. This is because Linux will fall back to setting a line | |
4edf1827 | 11 | * to N_TTY if it can not switch to any other line discipline. |
1da177e4 LT |
12 | * |
13 | * Written by Theodore Ts'o, Copyright 1994. | |
4edf1827 | 14 | * |
1da177e4 LT |
15 | * This file also contains code originally written by Linus Torvalds, |
16 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. | |
4edf1827 | 17 | * |
1da177e4 LT |
18 | * This file may be redistributed under the terms of the GNU General Public |
19 | * License. | |
20 | * | |
21 | * Reduced memory usage for older ARM systems - Russell King. | |
22 | * | |
4edf1827 | 23 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
1da177e4 LT |
24 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
25 | * who actually finally proved there really was a race. | |
26 | * | |
27 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to | |
28 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. | |
11a96d18 | 29 | * Also fixed a bug in BLOCKING mode where n_tty_write returns |
1da177e4 LT |
30 | * EAGAIN |
31 | */ | |
32 | ||
33 | #include <linux/types.h> | |
34 | #include <linux/major.h> | |
35 | #include <linux/errno.h> | |
36 | #include <linux/signal.h> | |
37 | #include <linux/fcntl.h> | |
38 | #include <linux/sched.h> | |
39 | #include <linux/interrupt.h> | |
40 | #include <linux/tty.h> | |
41 | #include <linux/timer.h> | |
42 | #include <linux/ctype.h> | |
43 | #include <linux/mm.h> | |
44 | #include <linux/string.h> | |
45 | #include <linux/slab.h> | |
46 | #include <linux/poll.h> | |
47 | #include <linux/bitops.h> | |
522ed776 MT |
48 | #include <linux/audit.h> |
49 | #include <linux/file.h> | |
300a6204 | 50 | #include <linux/uaccess.h> |
572b9adb | 51 | #include <linux/module.h> |
1da177e4 | 52 | |
1da177e4 LT |
53 | |
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 */ | |
bbd20759 | 63 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
1da177e4 | 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 | ||
70ece7a7 | 76 | struct n_tty_data { |
53c5ee2c JS |
77 | unsigned int column; |
78 | unsigned long overrun_time; | |
79 | int num_overrun; | |
80 | ||
81 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; | |
82 | unsigned char echo_overrun:1; | |
3fe780b3 JS |
83 | |
84 | DECLARE_BITMAP(process_char_map, 256); | |
85 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); | |
70ece7a7 JS |
86 | }; |
87 | ||
522ed776 MT |
88 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
89 | unsigned char __user *ptr) | |
90 | { | |
53c5ee2c JS |
91 | struct n_tty_data *ldata = tty->disc_data; |
92 | ||
93 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
94 | return put_user(x, ptr); |
95 | } | |
96 | ||
55db4c64 LT |
97 | /** |
98 | * n_tty_set__room - receive space | |
99 | * @tty: terminal | |
100 | * | |
101 | * Called by the driver to find out how much data it is | |
102 | * permitted to feed to the line discipline without any being lost | |
103 | * and thus to manage flow control. Not serialized. Answers for the | |
104 | * "instant". | |
105 | */ | |
106 | ||
107 | static void n_tty_set_room(struct tty_struct *tty) | |
108 | { | |
53c5ee2c | 109 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 110 | int left; |
55db4c64 LT |
111 | int old_left; |
112 | ||
090abf7b JA |
113 | /* tty->read_cnt is not read locked ? */ |
114 | if (I_PARMRK(tty)) { | |
115 | /* Multiply read_cnt by 3, since each byte might take up to | |
116 | * three times as many spaces when PARMRK is set (depending on | |
117 | * its flags, e.g. parity error). */ | |
118 | left = N_TTY_BUF_SIZE - tty->read_cnt * 3 - 1; | |
119 | } else | |
120 | left = N_TTY_BUF_SIZE - tty->read_cnt - 1; | |
121 | ||
55db4c64 LT |
122 | /* |
123 | * If we are doing input canonicalization, and there are no | |
124 | * pending newlines, let characters through without limit, so | |
125 | * that erase characters will be handled. Other excess | |
126 | * characters will be beeped. | |
127 | */ | |
128 | if (left <= 0) | |
53c5ee2c | 129 | left = ldata->icanon && !tty->canon_data; |
55db4c64 LT |
130 | old_left = tty->receive_room; |
131 | tty->receive_room = left; | |
132 | ||
133 | /* Did this open up the receive buffer? We may need to flip */ | |
134 | if (left && !old_left) | |
135 | schedule_work(&tty->buf.work); | |
136 | } | |
137 | ||
33f0f88f | 138 | static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty) |
1da177e4 LT |
139 | { |
140 | if (tty->read_cnt < N_TTY_BUF_SIZE) { | |
141 | tty->read_buf[tty->read_head] = c; | |
142 | tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1); | |
143 | tty->read_cnt++; | |
144 | } | |
145 | } | |
146 | ||
17b82060 AC |
147 | /** |
148 | * put_tty_queue - add character to tty | |
149 | * @c: character | |
150 | * @tty: tty device | |
151 | * | |
152 | * Add a character to the tty read_buf queue. This is done under the | |
153 | * read_lock to serialize character addition and also to protect us | |
154 | * against parallel reads or flushes | |
155 | */ | |
156 | ||
33f0f88f | 157 | static void put_tty_queue(unsigned char c, struct tty_struct *tty) |
1da177e4 LT |
158 | { |
159 | unsigned long flags; | |
160 | /* | |
161 | * The problem of stomping on the buffers ends here. | |
162 | * Why didn't anyone see this one coming? --AJK | |
163 | */ | |
164 | spin_lock_irqsave(&tty->read_lock, flags); | |
165 | put_tty_queue_nolock(c, tty); | |
166 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
167 | } | |
168 | ||
169 | /** | |
170 | * check_unthrottle - allow new receive data | |
171 | * @tty; tty device | |
172 | * | |
17b82060 AC |
173 | * Check whether to call the driver unthrottle functions |
174 | * | |
70522e12 | 175 | * Can sleep, may be called under the atomic_read_lock mutex but |
1da177e4 LT |
176 | * this is not guaranteed. |
177 | */ | |
4edf1827 | 178 | static void check_unthrottle(struct tty_struct *tty) |
1da177e4 | 179 | { |
39c2e60f AC |
180 | if (tty->count) |
181 | tty_unthrottle(tty); | |
1da177e4 LT |
182 | } |
183 | ||
184 | /** | |
185 | * reset_buffer_flags - reset buffer state | |
186 | * @tty: terminal to reset | |
187 | * | |
4edf1827 | 188 | * Reset the read buffer counters, clear the flags, |
1da177e4 LT |
189 | * and make sure the driver is unthrottled. Called |
190 | * from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 AC |
191 | * |
192 | * Locking: tty_read_lock for read fields. | |
1da177e4 | 193 | */ |
a88a69c9 | 194 | |
1da177e4 LT |
195 | static void reset_buffer_flags(struct tty_struct *tty) |
196 | { | |
53c5ee2c | 197 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
198 | unsigned long flags; |
199 | ||
200 | spin_lock_irqsave(&tty->read_lock, flags); | |
201 | tty->read_head = tty->read_tail = tty->read_cnt = 0; | |
202 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
a88a69c9 JP |
203 | |
204 | mutex_lock(&tty->echo_lock); | |
53c5ee2c | 205 | tty->echo_pos = tty->echo_cnt = ldata->echo_overrun = 0; |
a88a69c9 JP |
206 | mutex_unlock(&tty->echo_lock); |
207 | ||
53c5ee2c | 208 | tty->canon_head = tty->canon_data = ldata->erasing = 0; |
3fe780b3 | 209 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
55db4c64 | 210 | n_tty_set_room(tty); |
1da177e4 LT |
211 | } |
212 | ||
213 | /** | |
214 | * n_tty_flush_buffer - clean input queue | |
215 | * @tty: terminal device | |
216 | * | |
217 | * Flush the input buffer. Called when the line discipline is | |
218 | * being closed, when the tty layer wants the buffer flushed (eg | |
219 | * at hangup) or when the N_TTY line discipline internally has to | |
220 | * clean the pending queue (for example some signals). | |
221 | * | |
17b82060 | 222 | * Locking: ctrl_lock, read_lock. |
1da177e4 | 223 | */ |
4edf1827 AC |
224 | |
225 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 226 | { |
04f378b1 | 227 | unsigned long flags; |
1da177e4 LT |
228 | /* clear everything and unthrottle the driver */ |
229 | reset_buffer_flags(tty); | |
4edf1827 | 230 | |
1da177e4 LT |
231 | if (!tty->link) |
232 | return; | |
233 | ||
04f378b1 | 234 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
1da177e4 LT |
235 | if (tty->link->packet) { |
236 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
237 | wake_up_interruptible(&tty->link->read_wait); | |
238 | } | |
04f378b1 | 239 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1da177e4 LT |
240 | } |
241 | ||
242 | /** | |
243 | * n_tty_chars_in_buffer - report available bytes | |
244 | * @tty: tty device | |
245 | * | |
246 | * Report the number of characters buffered to be delivered to user | |
4edf1827 | 247 | * at this instant in time. |
17b82060 AC |
248 | * |
249 | * Locking: read_lock | |
1da177e4 | 250 | */ |
4edf1827 | 251 | |
1da177e4 LT |
252 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
253 | { | |
53c5ee2c | 254 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
255 | unsigned long flags; |
256 | ssize_t n = 0; | |
257 | ||
258 | spin_lock_irqsave(&tty->read_lock, flags); | |
53c5ee2c | 259 | if (!ldata->icanon) { |
1da177e4 LT |
260 | n = tty->read_cnt; |
261 | } else if (tty->canon_data) { | |
262 | n = (tty->canon_head > tty->read_tail) ? | |
263 | tty->canon_head - tty->read_tail : | |
264 | tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail); | |
265 | } | |
266 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
267 | return n; | |
268 | } | |
269 | ||
270 | /** | |
271 | * is_utf8_continuation - utf8 multibyte check | |
272 | * @c: byte to check | |
273 | * | |
274 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
275 | * character. We use this to correctly compute the on screen size | |
276 | * of the character when printing | |
277 | */ | |
4edf1827 | 278 | |
1da177e4 LT |
279 | static inline int is_utf8_continuation(unsigned char c) |
280 | { | |
281 | return (c & 0xc0) == 0x80; | |
282 | } | |
283 | ||
284 | /** | |
285 | * is_continuation - multibyte check | |
286 | * @c: byte to check | |
287 | * | |
288 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
289 | * character and the terminal is in unicode mode. | |
290 | */ | |
4edf1827 | 291 | |
1da177e4 LT |
292 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
293 | { | |
294 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
295 | } | |
296 | ||
297 | /** | |
a88a69c9 | 298 | * do_output_char - output one character |
1da177e4 LT |
299 | * @c: character (or partial unicode symbol) |
300 | * @tty: terminal device | |
a88a69c9 | 301 | * @space: space available in tty driver write buffer |
1da177e4 | 302 | * |
a88a69c9 JP |
303 | * This is a helper function that handles one output character |
304 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
305 | * doing OPOST processing and putting the results in the |
306 | * tty driver's write buffer. | |
a88a69c9 JP |
307 | * |
308 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
309 | * and NLDLY. They simply aren't relevant in the world today. | |
310 | * If you ever need them, add them here. | |
1da177e4 | 311 | * |
a88a69c9 JP |
312 | * Returns the number of bytes of buffer space used or -1 if |
313 | * no space left. | |
314 | * | |
315 | * Locking: should be called under the output_lock to protect | |
316 | * the column state and space left in the buffer | |
1da177e4 | 317 | */ |
4edf1827 | 318 | |
a88a69c9 | 319 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 320 | { |
53c5ee2c | 321 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 322 | int spaces; |
1da177e4 | 323 | |
1da177e4 LT |
324 | if (!space) |
325 | return -1; | |
300a6204 | 326 | |
a88a69c9 JP |
327 | switch (c) { |
328 | case '\n': | |
329 | if (O_ONLRET(tty)) | |
53c5ee2c | 330 | ldata->column = 0; |
a88a69c9 JP |
331 | if (O_ONLCR(tty)) { |
332 | if (space < 2) | |
333 | return -1; | |
53c5ee2c | 334 | tty->canon_column = ldata->column = 0; |
37f81fa1 | 335 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
336 | return 2; |
337 | } | |
53c5ee2c | 338 | tty->canon_column = ldata->column; |
a88a69c9 JP |
339 | break; |
340 | case '\r': | |
53c5ee2c | 341 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
342 | return 0; |
343 | if (O_OCRNL(tty)) { | |
344 | c = '\n'; | |
345 | if (O_ONLRET(tty)) | |
53c5ee2c | 346 | tty->canon_column = ldata->column = 0; |
1da177e4 | 347 | break; |
a88a69c9 | 348 | } |
53c5ee2c | 349 | tty->canon_column = ldata->column = 0; |
a88a69c9 JP |
350 | break; |
351 | case '\t': | |
53c5ee2c | 352 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
353 | if (O_TABDLY(tty) == XTABS) { |
354 | if (space < spaces) | |
355 | return -1; | |
53c5ee2c | 356 | ldata->column += spaces; |
a88a69c9 JP |
357 | tty->ops->write(tty, " ", spaces); |
358 | return spaces; | |
1da177e4 | 359 | } |
53c5ee2c | 360 | ldata->column += spaces; |
a88a69c9 JP |
361 | break; |
362 | case '\b': | |
53c5ee2c JS |
363 | if (ldata->column > 0) |
364 | ldata->column--; | |
a88a69c9 JP |
365 | break; |
366 | default: | |
a59c0d6f JP |
367 | if (!iscntrl(c)) { |
368 | if (O_OLCUC(tty)) | |
369 | c = toupper(c); | |
370 | if (!is_continuation(c, tty)) | |
53c5ee2c | 371 | ldata->column++; |
a59c0d6f | 372 | } |
a88a69c9 | 373 | break; |
1da177e4 | 374 | } |
a88a69c9 | 375 | |
f34d7a5b | 376 | tty_put_char(tty, c); |
a88a69c9 JP |
377 | return 1; |
378 | } | |
379 | ||
380 | /** | |
381 | * process_output - output post processor | |
382 | * @c: character (or partial unicode symbol) | |
383 | * @tty: terminal device | |
384 | * | |
ee5aa7b8 JP |
385 | * Output one character with OPOST processing. |
386 | * Returns -1 when the output device is full and the character | |
387 | * must be retried. | |
a88a69c9 JP |
388 | * |
389 | * Locking: output_lock to protect column state and space left | |
390 | * (also, this is called from n_tty_write under the | |
391 | * tty layer write lock) | |
392 | */ | |
393 | ||
394 | static int process_output(unsigned char c, struct tty_struct *tty) | |
395 | { | |
396 | int space, retval; | |
397 | ||
398 | mutex_lock(&tty->output_lock); | |
399 | ||
400 | space = tty_write_room(tty); | |
401 | retval = do_output_char(c, tty, space); | |
402 | ||
403 | mutex_unlock(&tty->output_lock); | |
404 | if (retval < 0) | |
405 | return -1; | |
406 | else | |
407 | return 0; | |
1da177e4 LT |
408 | } |
409 | ||
410 | /** | |
a88a69c9 | 411 | * process_output_block - block post processor |
1da177e4 | 412 | * @tty: terminal device |
ee5aa7b8 JP |
413 | * @buf: character buffer |
414 | * @nr: number of bytes to output | |
415 | * | |
416 | * Output a block of characters with OPOST processing. | |
417 | * Returns the number of characters output. | |
1da177e4 LT |
418 | * |
419 | * This path is used to speed up block console writes, among other | |
420 | * things when processing blocks of output data. It handles only | |
421 | * the simple cases normally found and helps to generate blocks of | |
422 | * symbols for the console driver and thus improve performance. | |
423 | * | |
a88a69c9 JP |
424 | * Locking: output_lock to protect column state and space left |
425 | * (also, this is called from n_tty_write under the | |
426 | * tty layer write lock) | |
1da177e4 | 427 | */ |
4edf1827 | 428 | |
a88a69c9 JP |
429 | static ssize_t process_output_block(struct tty_struct *tty, |
430 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 431 | { |
53c5ee2c | 432 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 433 | int space; |
bbd20759 | 434 | int i; |
1da177e4 LT |
435 | const unsigned char *cp; |
436 | ||
a88a69c9 JP |
437 | mutex_lock(&tty->output_lock); |
438 | ||
f34d7a5b | 439 | space = tty_write_room(tty); |
300a6204 | 440 | if (!space) { |
a88a69c9 | 441 | mutex_unlock(&tty->output_lock); |
1da177e4 | 442 | return 0; |
a88a69c9 | 443 | } |
1da177e4 LT |
444 | if (nr > space) |
445 | nr = space; | |
446 | ||
447 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
448 | unsigned char c = *cp; |
449 | ||
450 | switch (c) { | |
1da177e4 LT |
451 | case '\n': |
452 | if (O_ONLRET(tty)) | |
53c5ee2c | 453 | ldata->column = 0; |
1da177e4 LT |
454 | if (O_ONLCR(tty)) |
455 | goto break_out; | |
53c5ee2c | 456 | tty->canon_column = ldata->column; |
1da177e4 LT |
457 | break; |
458 | case '\r': | |
53c5ee2c | 459 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
460 | goto break_out; |
461 | if (O_OCRNL(tty)) | |
462 | goto break_out; | |
53c5ee2c | 463 | tty->canon_column = ldata->column = 0; |
1da177e4 LT |
464 | break; |
465 | case '\t': | |
466 | goto break_out; | |
467 | case '\b': | |
53c5ee2c JS |
468 | if (ldata->column > 0) |
469 | ldata->column--; | |
1da177e4 LT |
470 | break; |
471 | default: | |
a59c0d6f JP |
472 | if (!iscntrl(c)) { |
473 | if (O_OLCUC(tty)) | |
474 | goto break_out; | |
475 | if (!is_continuation(c, tty)) | |
53c5ee2c | 476 | ldata->column++; |
a59c0d6f | 477 | } |
1da177e4 LT |
478 | break; |
479 | } | |
480 | } | |
481 | break_out: | |
f34d7a5b | 482 | i = tty->ops->write(tty, buf, i); |
a88a69c9 JP |
483 | |
484 | mutex_unlock(&tty->output_lock); | |
1da177e4 LT |
485 | return i; |
486 | } | |
487 | ||
a88a69c9 JP |
488 | /** |
489 | * process_echoes - write pending echo characters | |
490 | * @tty: terminal device | |
491 | * | |
492 | * Write previously buffered echo (and other ldisc-generated) | |
493 | * characters to the tty. | |
494 | * | |
495 | * Characters generated by the ldisc (including echoes) need to | |
496 | * be buffered because the driver's write buffer can fill during | |
497 | * heavy program output. Echoing straight to the driver will | |
498 | * often fail under these conditions, causing lost characters and | |
499 | * resulting mismatches of ldisc state information. | |
500 | * | |
501 | * Since the ldisc state must represent the characters actually sent | |
502 | * to the driver at the time of the write, operations like certain | |
503 | * changes in column state are also saved in the buffer and executed | |
504 | * here. | |
505 | * | |
506 | * A circular fifo buffer is used so that the most recent characters | |
507 | * are prioritized. Also, when control characters are echoed with a | |
508 | * prefixed "^", the pair is treated atomically and thus not separated. | |
509 | * | |
510 | * Locking: output_lock to protect column state and space left, | |
511 | * echo_lock to protect the echo buffer | |
512 | */ | |
513 | ||
514 | static void process_echoes(struct tty_struct *tty) | |
515 | { | |
53c5ee2c | 516 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
517 | int space, nr; |
518 | unsigned char c; | |
519 | unsigned char *cp, *buf_end; | |
520 | ||
521 | if (!tty->echo_cnt) | |
522 | return; | |
523 | ||
524 | mutex_lock(&tty->output_lock); | |
525 | mutex_lock(&tty->echo_lock); | |
526 | ||
527 | space = tty_write_room(tty); | |
528 | ||
529 | buf_end = tty->echo_buf + N_TTY_BUF_SIZE; | |
530 | cp = tty->echo_buf + tty->echo_pos; | |
531 | nr = tty->echo_cnt; | |
532 | while (nr > 0) { | |
533 | c = *cp; | |
534 | if (c == ECHO_OP_START) { | |
535 | unsigned char op; | |
536 | unsigned char *opp; | |
537 | int no_space_left = 0; | |
538 | ||
539 | /* | |
540 | * If the buffer byte is the start of a multi-byte | |
541 | * operation, get the next byte, which is either the | |
542 | * op code or a control character value. | |
543 | */ | |
544 | opp = cp + 1; | |
545 | if (opp == buf_end) | |
546 | opp -= N_TTY_BUF_SIZE; | |
547 | op = *opp; | |
300a6204 | 548 | |
a88a69c9 JP |
549 | switch (op) { |
550 | unsigned int num_chars, num_bs; | |
551 | ||
552 | case ECHO_OP_ERASE_TAB: | |
553 | if (++opp == buf_end) | |
554 | opp -= N_TTY_BUF_SIZE; | |
555 | num_chars = *opp; | |
556 | ||
557 | /* | |
558 | * Determine how many columns to go back | |
559 | * in order to erase the tab. | |
560 | * This depends on the number of columns | |
561 | * used by other characters within the tab | |
562 | * area. If this (modulo 8) count is from | |
563 | * the start of input rather than from a | |
564 | * previous tab, we offset by canon column. | |
565 | * Otherwise, tab spacing is normal. | |
566 | */ | |
567 | if (!(num_chars & 0x80)) | |
568 | num_chars += tty->canon_column; | |
569 | num_bs = 8 - (num_chars & 7); | |
570 | ||
571 | if (num_bs > space) { | |
572 | no_space_left = 1; | |
573 | break; | |
574 | } | |
575 | space -= num_bs; | |
576 | while (num_bs--) { | |
577 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
578 | if (ldata->column > 0) |
579 | ldata->column--; | |
a88a69c9 JP |
580 | } |
581 | cp += 3; | |
582 | nr -= 3; | |
583 | break; | |
584 | ||
585 | case ECHO_OP_SET_CANON_COL: | |
53c5ee2c | 586 | tty->canon_column = ldata->column; |
a88a69c9 JP |
587 | cp += 2; |
588 | nr -= 2; | |
589 | break; | |
590 | ||
591 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
592 | if (ldata->column > 0) |
593 | ldata->column--; | |
a88a69c9 JP |
594 | cp += 2; |
595 | nr -= 2; | |
596 | break; | |
597 | ||
598 | case ECHO_OP_START: | |
599 | /* This is an escaped echo op start code */ | |
600 | if (!space) { | |
601 | no_space_left = 1; | |
602 | break; | |
603 | } | |
604 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 605 | ldata->column++; |
a88a69c9 JP |
606 | space--; |
607 | cp += 2; | |
608 | nr -= 2; | |
609 | break; | |
610 | ||
611 | default: | |
a88a69c9 | 612 | /* |
62b26358 JP |
613 | * If the op is not a special byte code, |
614 | * it is a ctrl char tagged to be echoed | |
615 | * as "^X" (where X is the letter | |
616 | * representing the control char). | |
617 | * Note that we must ensure there is | |
618 | * enough space for the whole ctrl pair. | |
619 | * | |
a88a69c9 | 620 | */ |
62b26358 JP |
621 | if (space < 2) { |
622 | no_space_left = 1; | |
623 | break; | |
624 | } | |
625 | tty_put_char(tty, '^'); | |
626 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 627 | ldata->column += 2; |
62b26358 | 628 | space -= 2; |
a88a69c9 JP |
629 | cp += 2; |
630 | nr -= 2; | |
631 | } | |
632 | ||
633 | if (no_space_left) | |
634 | break; | |
635 | } else { | |
ee5aa7b8 JP |
636 | if (O_OPOST(tty) && |
637 | !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
638 | int retval = do_output_char(c, tty, space); | |
639 | if (retval < 0) | |
640 | break; | |
641 | space -= retval; | |
642 | } else { | |
643 | if (!space) | |
644 | break; | |
645 | tty_put_char(tty, c); | |
646 | space -= 1; | |
647 | } | |
a88a69c9 JP |
648 | cp += 1; |
649 | nr -= 1; | |
650 | } | |
651 | ||
652 | /* When end of circular buffer reached, wrap around */ | |
653 | if (cp >= buf_end) | |
654 | cp -= N_TTY_BUF_SIZE; | |
655 | } | |
656 | ||
657 | if (nr == 0) { | |
658 | tty->echo_pos = 0; | |
659 | tty->echo_cnt = 0; | |
53c5ee2c | 660 | ldata->echo_overrun = 0; |
a88a69c9 JP |
661 | } else { |
662 | int num_processed = tty->echo_cnt - nr; | |
663 | tty->echo_pos += num_processed; | |
664 | tty->echo_pos &= N_TTY_BUF_SIZE - 1; | |
665 | tty->echo_cnt = nr; | |
666 | if (num_processed > 0) | |
53c5ee2c | 667 | ldata->echo_overrun = 0; |
a88a69c9 JP |
668 | } |
669 | ||
670 | mutex_unlock(&tty->echo_lock); | |
671 | mutex_unlock(&tty->output_lock); | |
672 | ||
673 | if (tty->ops->flush_chars) | |
674 | tty->ops->flush_chars(tty); | |
675 | } | |
676 | ||
677 | /** | |
678 | * add_echo_byte - add a byte to the echo buffer | |
679 | * @c: unicode byte to echo | |
680 | * @tty: terminal device | |
681 | * | |
682 | * Add a character or operation byte to the echo buffer. | |
683 | * | |
684 | * Should be called under the echo lock to protect the echo buffer. | |
685 | */ | |
686 | ||
687 | static void add_echo_byte(unsigned char c, struct tty_struct *tty) | |
688 | { | |
53c5ee2c | 689 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
690 | int new_byte_pos; |
691 | ||
692 | if (tty->echo_cnt == N_TTY_BUF_SIZE) { | |
693 | /* Circular buffer is already at capacity */ | |
694 | new_byte_pos = tty->echo_pos; | |
695 | ||
696 | /* | |
697 | * Since the buffer start position needs to be advanced, | |
698 | * be sure to step by a whole operation byte group. | |
699 | */ | |
300a6204 | 700 | if (tty->echo_buf[tty->echo_pos] == ECHO_OP_START) { |
a88a69c9 JP |
701 | if (tty->echo_buf[(tty->echo_pos + 1) & |
702 | (N_TTY_BUF_SIZE - 1)] == | |
703 | ECHO_OP_ERASE_TAB) { | |
704 | tty->echo_pos += 3; | |
705 | tty->echo_cnt -= 2; | |
706 | } else { | |
707 | tty->echo_pos += 2; | |
708 | tty->echo_cnt -= 1; | |
709 | } | |
710 | } else { | |
711 | tty->echo_pos++; | |
712 | } | |
713 | tty->echo_pos &= N_TTY_BUF_SIZE - 1; | |
714 | ||
53c5ee2c | 715 | ldata->echo_overrun = 1; |
a88a69c9 JP |
716 | } else { |
717 | new_byte_pos = tty->echo_pos + tty->echo_cnt; | |
718 | new_byte_pos &= N_TTY_BUF_SIZE - 1; | |
719 | tty->echo_cnt++; | |
720 | } | |
721 | ||
722 | tty->echo_buf[new_byte_pos] = c; | |
723 | } | |
724 | ||
725 | /** | |
726 | * echo_move_back_col - add operation to move back a column | |
727 | * @tty: terminal device | |
728 | * | |
729 | * Add an operation to the echo buffer to move back one column. | |
730 | * | |
731 | * Locking: echo_lock to protect the echo buffer | |
732 | */ | |
733 | ||
734 | static void echo_move_back_col(struct tty_struct *tty) | |
735 | { | |
736 | mutex_lock(&tty->echo_lock); | |
737 | ||
738 | add_echo_byte(ECHO_OP_START, tty); | |
739 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty); | |
740 | ||
741 | mutex_unlock(&tty->echo_lock); | |
742 | } | |
743 | ||
744 | /** | |
745 | * echo_set_canon_col - add operation to set the canon column | |
746 | * @tty: terminal device | |
747 | * | |
748 | * Add an operation to the echo buffer to set the canon column | |
749 | * to the current column. | |
750 | * | |
751 | * Locking: echo_lock to protect the echo buffer | |
752 | */ | |
753 | ||
754 | static void echo_set_canon_col(struct tty_struct *tty) | |
755 | { | |
756 | mutex_lock(&tty->echo_lock); | |
757 | ||
758 | add_echo_byte(ECHO_OP_START, tty); | |
759 | add_echo_byte(ECHO_OP_SET_CANON_COL, tty); | |
760 | ||
761 | mutex_unlock(&tty->echo_lock); | |
762 | } | |
763 | ||
764 | /** | |
765 | * echo_erase_tab - add operation to erase a tab | |
766 | * @num_chars: number of character columns already used | |
767 | * @after_tab: true if num_chars starts after a previous tab | |
768 | * @tty: terminal device | |
769 | * | |
770 | * Add an operation to the echo buffer to erase a tab. | |
771 | * | |
772 | * Called by the eraser function, which knows how many character | |
773 | * columns have been used since either a previous tab or the start | |
774 | * of input. This information will be used later, along with | |
775 | * canon column (if applicable), to go back the correct number | |
776 | * of columns. | |
777 | * | |
778 | * Locking: echo_lock to protect the echo buffer | |
779 | */ | |
780 | ||
781 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
782 | struct tty_struct *tty) | |
783 | { | |
784 | mutex_lock(&tty->echo_lock); | |
785 | ||
786 | add_echo_byte(ECHO_OP_START, tty); | |
787 | add_echo_byte(ECHO_OP_ERASE_TAB, tty); | |
788 | ||
789 | /* We only need to know this modulo 8 (tab spacing) */ | |
790 | num_chars &= 7; | |
791 | ||
792 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
793 | if (after_tab) | |
794 | num_chars |= 0x80; | |
300a6204 | 795 | |
a88a69c9 JP |
796 | add_echo_byte(num_chars, tty); |
797 | ||
798 | mutex_unlock(&tty->echo_lock); | |
799 | } | |
800 | ||
801 | /** | |
802 | * echo_char_raw - echo a character raw | |
803 | * @c: unicode byte to echo | |
804 | * @tty: terminal device | |
805 | * | |
806 | * Echo user input back onto the screen. This must be called only when | |
807 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
808 | * | |
809 | * This variant does not treat control characters specially. | |
810 | * | |
811 | * Locking: echo_lock to protect the echo buffer | |
812 | */ | |
813 | ||
814 | static void echo_char_raw(unsigned char c, struct tty_struct *tty) | |
815 | { | |
816 | mutex_lock(&tty->echo_lock); | |
817 | ||
818 | if (c == ECHO_OP_START) { | |
819 | add_echo_byte(ECHO_OP_START, tty); | |
820 | add_echo_byte(ECHO_OP_START, tty); | |
821 | } else { | |
822 | add_echo_byte(c, tty); | |
823 | } | |
824 | ||
825 | mutex_unlock(&tty->echo_lock); | |
826 | } | |
1da177e4 | 827 | |
1da177e4 | 828 | /** |
a88a69c9 | 829 | * echo_char - echo a character |
1da177e4 LT |
830 | * @c: unicode byte to echo |
831 | * @tty: terminal device | |
832 | * | |
4edf1827 | 833 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 834 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 835 | * |
62b26358 JP |
836 | * This variant tags control characters to be echoed as "^X" |
837 | * (where X is the letter representing the control char). | |
a88a69c9 JP |
838 | * |
839 | * Locking: echo_lock to protect the echo buffer | |
1da177e4 LT |
840 | */ |
841 | ||
842 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
843 | { | |
a88a69c9 JP |
844 | mutex_lock(&tty->echo_lock); |
845 | ||
846 | if (c == ECHO_OP_START) { | |
847 | add_echo_byte(ECHO_OP_START, tty); | |
848 | add_echo_byte(ECHO_OP_START, tty); | |
849 | } else { | |
62b26358 | 850 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
a88a69c9 JP |
851 | add_echo_byte(ECHO_OP_START, tty); |
852 | add_echo_byte(c, tty); | |
853 | } | |
854 | ||
855 | mutex_unlock(&tty->echo_lock); | |
1da177e4 LT |
856 | } |
857 | ||
17b82060 | 858 | /** |
a88a69c9 | 859 | * finish_erasing - complete erase |
17b82060 | 860 | * @tty: tty doing the erase |
17b82060 | 861 | */ |
a88a69c9 | 862 | |
1da177e4 LT |
863 | static inline void finish_erasing(struct tty_struct *tty) |
864 | { | |
53c5ee2c JS |
865 | struct n_tty_data *ldata = tty->disc_data; |
866 | if (ldata->erasing) { | |
a88a69c9 | 867 | echo_char_raw('/', tty); |
53c5ee2c | 868 | ldata->erasing = 0; |
1da177e4 LT |
869 | } |
870 | } | |
871 | ||
872 | /** | |
873 | * eraser - handle erase function | |
874 | * @c: character input | |
875 | * @tty: terminal device | |
876 | * | |
3a4fa0a2 | 877 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
878 | * present in the stream from the driver layer. Handles the complexities |
879 | * of UTF-8 multibyte symbols. | |
17b82060 | 880 | * |
a88a69c9 | 881 | * Locking: read_lock for tty buffers |
1da177e4 | 882 | */ |
4edf1827 | 883 | |
1da177e4 LT |
884 | static void eraser(unsigned char c, struct tty_struct *tty) |
885 | { | |
53c5ee2c | 886 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
887 | enum { ERASE, WERASE, KILL } kill_type; |
888 | int head, seen_alnums, cnt; | |
889 | unsigned long flags; | |
890 | ||
17b82060 | 891 | /* FIXME: locking needed ? */ |
1da177e4 | 892 | if (tty->read_head == tty->canon_head) { |
7e94b1d9 | 893 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
894 | return; |
895 | } | |
896 | if (c == ERASE_CHAR(tty)) | |
897 | kill_type = ERASE; | |
898 | else if (c == WERASE_CHAR(tty)) | |
899 | kill_type = WERASE; | |
900 | else { | |
901 | if (!L_ECHO(tty)) { | |
902 | spin_lock_irqsave(&tty->read_lock, flags); | |
903 | tty->read_cnt -= ((tty->read_head - tty->canon_head) & | |
904 | (N_TTY_BUF_SIZE - 1)); | |
905 | tty->read_head = tty->canon_head; | |
906 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
907 | return; | |
908 | } | |
909 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
910 | spin_lock_irqsave(&tty->read_lock, flags); | |
911 | tty->read_cnt -= ((tty->read_head - tty->canon_head) & | |
912 | (N_TTY_BUF_SIZE - 1)); | |
913 | tty->read_head = tty->canon_head; | |
914 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
915 | finish_erasing(tty); | |
916 | echo_char(KILL_CHAR(tty), tty); | |
917 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
918 | if (L_ECHOK(tty)) | |
a88a69c9 | 919 | echo_char_raw('\n', tty); |
1da177e4 LT |
920 | return; |
921 | } | |
922 | kill_type = KILL; | |
923 | } | |
924 | ||
925 | seen_alnums = 0; | |
17b82060 | 926 | /* FIXME: Locking ?? */ |
1da177e4 LT |
927 | while (tty->read_head != tty->canon_head) { |
928 | head = tty->read_head; | |
929 | ||
930 | /* erase a single possibly multibyte character */ | |
931 | do { | |
932 | head = (head - 1) & (N_TTY_BUF_SIZE-1); | |
933 | c = tty->read_buf[head]; | |
934 | } while (is_continuation(c, tty) && head != tty->canon_head); | |
935 | ||
936 | /* do not partially erase */ | |
937 | if (is_continuation(c, tty)) | |
938 | break; | |
939 | ||
940 | if (kill_type == WERASE) { | |
941 | /* Equivalent to BSD's ALTWERASE. */ | |
942 | if (isalnum(c) || c == '_') | |
943 | seen_alnums++; | |
944 | else if (seen_alnums) | |
945 | break; | |
946 | } | |
947 | cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1); | |
948 | spin_lock_irqsave(&tty->read_lock, flags); | |
949 | tty->read_head = head; | |
950 | tty->read_cnt -= cnt; | |
951 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
952 | if (L_ECHO(tty)) { | |
953 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 954 | if (!ldata->erasing) { |
a88a69c9 | 955 | echo_char_raw('\\', tty); |
53c5ee2c | 956 | ldata->erasing = 1; |
1da177e4 LT |
957 | } |
958 | /* if cnt > 1, output a multi-byte character */ | |
959 | echo_char(c, tty); | |
960 | while (--cnt > 0) { | |
961 | head = (head+1) & (N_TTY_BUF_SIZE-1); | |
a88a69c9 JP |
962 | echo_char_raw(tty->read_buf[head], tty); |
963 | echo_move_back_col(tty); | |
1da177e4 LT |
964 | } |
965 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
966 | echo_char(ERASE_CHAR(tty), tty); | |
967 | } else if (c == '\t') { | |
a88a69c9 JP |
968 | unsigned int num_chars = 0; |
969 | int after_tab = 0; | |
970 | unsigned long tail = tty->read_head; | |
971 | ||
972 | /* | |
973 | * Count the columns used for characters | |
974 | * since the start of input or after a | |
975 | * previous tab. | |
976 | * This info is used to go back the correct | |
977 | * number of columns. | |
978 | */ | |
979 | while (tail != tty->canon_head) { | |
980 | tail = (tail-1) & (N_TTY_BUF_SIZE-1); | |
1da177e4 | 981 | c = tty->read_buf[tail]; |
a88a69c9 JP |
982 | if (c == '\t') { |
983 | after_tab = 1; | |
984 | break; | |
300a6204 | 985 | } else if (iscntrl(c)) { |
1da177e4 | 986 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
987 | num_chars += 2; |
988 | } else if (!is_continuation(c, tty)) { | |
989 | num_chars++; | |
990 | } | |
1da177e4 | 991 | } |
a88a69c9 | 992 | echo_erase_tab(num_chars, after_tab, tty); |
1da177e4 LT |
993 | } else { |
994 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
a88a69c9 JP |
995 | echo_char_raw('\b', tty); |
996 | echo_char_raw(' ', tty); | |
997 | echo_char_raw('\b', tty); | |
1da177e4 LT |
998 | } |
999 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
a88a69c9 JP |
1000 | echo_char_raw('\b', tty); |
1001 | echo_char_raw(' ', tty); | |
1002 | echo_char_raw('\b', tty); | |
1da177e4 LT |
1003 | } |
1004 | } | |
1005 | } | |
1006 | if (kill_type == ERASE) | |
1007 | break; | |
1008 | } | |
a88a69c9 | 1009 | if (tty->read_head == tty->canon_head && L_ECHO(tty)) |
1da177e4 LT |
1010 | finish_erasing(tty); |
1011 | } | |
1012 | ||
1013 | /** | |
1014 | * isig - handle the ISIG optio | |
1015 | * @sig: signal | |
1016 | * @tty: terminal | |
1017 | * @flush: force flush | |
1018 | * | |
1019 | * Called when a signal is being sent due to terminal input. This | |
1020 | * may caus terminal flushing to take place according to the termios | |
1021 | * settings and character used. Called from the driver receive_buf | |
1022 | * path so serialized. | |
17b82060 AC |
1023 | * |
1024 | * Locking: ctrl_lock, read_lock (both via flush buffer) | |
1da177e4 | 1025 | */ |
4edf1827 | 1026 | |
1da177e4 LT |
1027 | static inline void isig(int sig, struct tty_struct *tty, int flush) |
1028 | { | |
ab521dc0 EB |
1029 | if (tty->pgrp) |
1030 | kill_pgrp(tty->pgrp, sig, 1); | |
1da177e4 LT |
1031 | if (flush || !L_NOFLSH(tty)) { |
1032 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1033 | tty_driver_flush_buffer(tty); |
1da177e4 LT |
1034 | } |
1035 | } | |
1036 | ||
1037 | /** | |
1038 | * n_tty_receive_break - handle break | |
1039 | * @tty: terminal | |
1040 | * | |
1041 | * An RS232 break event has been hit in the incoming bitstream. This | |
1042 | * can cause a variety of events depending upon the termios settings. | |
1043 | * | |
1044 | * Called from the receive_buf path so single threaded. | |
1045 | */ | |
4edf1827 | 1046 | |
1da177e4 LT |
1047 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1048 | { | |
1049 | if (I_IGNBRK(tty)) | |
1050 | return; | |
1051 | if (I_BRKINT(tty)) { | |
1052 | isig(SIGINT, tty, 1); | |
1053 | return; | |
1054 | } | |
1055 | if (I_PARMRK(tty)) { | |
1056 | put_tty_queue('\377', tty); | |
1057 | put_tty_queue('\0', tty); | |
1058 | } | |
1059 | put_tty_queue('\0', tty); | |
1060 | wake_up_interruptible(&tty->read_wait); | |
1061 | } | |
1062 | ||
1063 | /** | |
1064 | * n_tty_receive_overrun - handle overrun reporting | |
1065 | * @tty: terminal | |
1066 | * | |
1067 | * Data arrived faster than we could process it. While the tty | |
1068 | * driver has flagged this the bits that were missed are gone | |
1069 | * forever. | |
1070 | * | |
1071 | * Called from the receive_buf path so single threaded. Does not | |
1072 | * need locking as num_overrun and overrun_time are function | |
1073 | * private. | |
1074 | */ | |
4edf1827 | 1075 | |
1da177e4 LT |
1076 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1077 | { | |
53c5ee2c | 1078 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1079 | char buf[64]; |
1080 | ||
53c5ee2c JS |
1081 | ldata->num_overrun++; |
1082 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1083 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1084 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1085 | tty_name(tty, buf), | |
53c5ee2c JS |
1086 | ldata->num_overrun); |
1087 | ldata->overrun_time = jiffies; | |
1088 | ldata->num_overrun = 0; | |
1da177e4 LT |
1089 | } |
1090 | } | |
1091 | ||
1092 | /** | |
1093 | * n_tty_receive_parity_error - error notifier | |
1094 | * @tty: terminal device | |
1095 | * @c: character | |
1096 | * | |
1097 | * Process a parity error and queue the right data to indicate | |
3a4fa0a2 | 1098 | * the error case if necessary. Locking as per n_tty_receive_buf. |
1da177e4 LT |
1099 | */ |
1100 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1101 | unsigned char c) | |
1102 | { | |
4edf1827 | 1103 | if (I_IGNPAR(tty)) |
1da177e4 | 1104 | return; |
1da177e4 LT |
1105 | if (I_PARMRK(tty)) { |
1106 | put_tty_queue('\377', tty); | |
1107 | put_tty_queue('\0', tty); | |
1108 | put_tty_queue(c, tty); | |
1109 | } else if (I_INPCK(tty)) | |
1110 | put_tty_queue('\0', tty); | |
1111 | else | |
1112 | put_tty_queue(c, tty); | |
1113 | wake_up_interruptible(&tty->read_wait); | |
1114 | } | |
1115 | ||
1116 | /** | |
1117 | * n_tty_receive_char - perform processing | |
1118 | * @tty: terminal device | |
1119 | * @c: character | |
1120 | * | |
1121 | * Process an individual character of input received from the driver. | |
4edf1827 | 1122 | * This is serialized with respect to itself by the rules for the |
1da177e4 LT |
1123 | * driver above. |
1124 | */ | |
1125 | ||
1126 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1127 | { | |
53c5ee2c | 1128 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1129 | unsigned long flags; |
acc71bba | 1130 | int parmrk; |
1da177e4 | 1131 | |
53c5ee2c | 1132 | if (ldata->raw) { |
1da177e4 LT |
1133 | put_tty_queue(c, tty); |
1134 | return; | |
1135 | } | |
4edf1827 | 1136 | |
1da177e4 LT |
1137 | if (I_ISTRIP(tty)) |
1138 | c &= 0x7f; | |
1139 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1140 | c = tolower(c); |
1da177e4 | 1141 | |
26df6d13 | 1142 | if (L_EXTPROC(tty)) { |
1143 | put_tty_queue(c, tty); | |
1144 | return; | |
1145 | } | |
1146 | ||
54d2a37e | 1147 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1148 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1149 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1150 | start_tty(tty); |
a88a69c9 JP |
1151 | process_echoes(tty); |
1152 | } | |
54d2a37e | 1153 | |
1da177e4 LT |
1154 | if (tty->closing) { |
1155 | if (I_IXON(tty)) { | |
a88a69c9 | 1156 | if (c == START_CHAR(tty)) { |
1da177e4 | 1157 | start_tty(tty); |
a88a69c9 | 1158 | process_echoes(tty); |
300a6204 | 1159 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1160 | stop_tty(tty); |
1161 | } | |
1162 | return; | |
1163 | } | |
1164 | ||
1165 | /* | |
1166 | * If the previous character was LNEXT, or we know that this | |
1167 | * character is not one of the characters that we'll have to | |
1168 | * handle specially, do shortcut processing to speed things | |
1169 | * up. | |
1170 | */ | |
3fe780b3 | 1171 | if (!test_bit(c, ldata->process_char_map) || ldata->lnext) { |
53c5ee2c | 1172 | ldata->lnext = 0; |
acc71bba JP |
1173 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
1174 | if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { | |
1175 | /* beep if no space */ | |
7e94b1d9 JP |
1176 | if (L_ECHO(tty)) |
1177 | process_output('\a', tty); | |
acc71bba JP |
1178 | return; |
1179 | } | |
1180 | if (L_ECHO(tty)) { | |
1181 | finish_erasing(tty); | |
1da177e4 LT |
1182 | /* Record the column of first canon char. */ |
1183 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1184 | echo_set_canon_col(tty); |
1da177e4 | 1185 | echo_char(c, tty); |
a88a69c9 | 1186 | process_echoes(tty); |
1da177e4 | 1187 | } |
acc71bba | 1188 | if (parmrk) |
1da177e4 LT |
1189 | put_tty_queue(c, tty); |
1190 | put_tty_queue(c, tty); | |
1191 | return; | |
1192 | } | |
4edf1827 | 1193 | |
1da177e4 LT |
1194 | if (I_IXON(tty)) { |
1195 | if (c == START_CHAR(tty)) { | |
1196 | start_tty(tty); | |
a88a69c9 | 1197 | process_echoes(tty); |
1da177e4 LT |
1198 | return; |
1199 | } | |
1200 | if (c == STOP_CHAR(tty)) { | |
1201 | stop_tty(tty); | |
1202 | return; | |
1203 | } | |
1204 | } | |
575537b3 | 1205 | |
1da177e4 LT |
1206 | if (L_ISIG(tty)) { |
1207 | int signal; | |
1208 | signal = SIGINT; | |
1209 | if (c == INTR_CHAR(tty)) | |
1210 | goto send_signal; | |
1211 | signal = SIGQUIT; | |
1212 | if (c == QUIT_CHAR(tty)) | |
1213 | goto send_signal; | |
1214 | signal = SIGTSTP; | |
1215 | if (c == SUSP_CHAR(tty)) { | |
1216 | send_signal: | |
ec5b1157 | 1217 | /* |
ec5b1157 JP |
1218 | * Note that we do not use isig() here because we want |
1219 | * the order to be: | |
1220 | * 1) flush, 2) echo, 3) signal | |
1221 | */ | |
1222 | if (!L_NOFLSH(tty)) { | |
1223 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1224 | tty_driver_flush_buffer(tty); |
ec5b1157 | 1225 | } |
a88a69c9 JP |
1226 | if (I_IXON(tty)) |
1227 | start_tty(tty); | |
1228 | if (L_ECHO(tty)) { | |
ec5b1157 | 1229 | echo_char(c, tty); |
a88a69c9 JP |
1230 | process_echoes(tty); |
1231 | } | |
ec5b1157 JP |
1232 | if (tty->pgrp) |
1233 | kill_pgrp(tty->pgrp, signal, 1); | |
1da177e4 LT |
1234 | return; |
1235 | } | |
1236 | } | |
575537b3 JP |
1237 | |
1238 | if (c == '\r') { | |
1239 | if (I_IGNCR(tty)) | |
1240 | return; | |
1241 | if (I_ICRNL(tty)) | |
1242 | c = '\n'; | |
1243 | } else if (c == '\n' && I_INLCR(tty)) | |
1244 | c = '\r'; | |
1245 | ||
53c5ee2c | 1246 | if (ldata->icanon) { |
1da177e4 LT |
1247 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1248 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1249 | eraser(c, tty); | |
a88a69c9 | 1250 | process_echoes(tty); |
1da177e4 LT |
1251 | return; |
1252 | } | |
1253 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1254 | ldata->lnext = 1; |
1da177e4 LT |
1255 | if (L_ECHO(tty)) { |
1256 | finish_erasing(tty); | |
1257 | if (L_ECHOCTL(tty)) { | |
a88a69c9 JP |
1258 | echo_char_raw('^', tty); |
1259 | echo_char_raw('\b', tty); | |
1260 | process_echoes(tty); | |
1da177e4 LT |
1261 | } |
1262 | } | |
1263 | return; | |
1264 | } | |
1265 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1266 | L_IEXTEN(tty)) { | |
1267 | unsigned long tail = tty->canon_head; | |
1268 | ||
1269 | finish_erasing(tty); | |
1270 | echo_char(c, tty); | |
a88a69c9 | 1271 | echo_char_raw('\n', tty); |
1da177e4 LT |
1272 | while (tail != tty->read_head) { |
1273 | echo_char(tty->read_buf[tail], tty); | |
1274 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
1275 | } | |
a88a69c9 | 1276 | process_echoes(tty); |
1da177e4 LT |
1277 | return; |
1278 | } | |
1279 | if (c == '\n') { | |
acc71bba | 1280 | if (tty->read_cnt >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1281 | if (L_ECHO(tty)) |
1282 | process_output('\a', tty); | |
acc71bba JP |
1283 | return; |
1284 | } | |
1285 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
a88a69c9 JP |
1286 | echo_char_raw('\n', tty); |
1287 | process_echoes(tty); | |
1da177e4 LT |
1288 | } |
1289 | goto handle_newline; | |
1290 | } | |
1291 | if (c == EOF_CHAR(tty)) { | |
acc71bba JP |
1292 | if (tty->read_cnt >= N_TTY_BUF_SIZE) |
1293 | return; | |
4edf1827 AC |
1294 | if (tty->canon_head != tty->read_head) |
1295 | set_bit(TTY_PUSH, &tty->flags); | |
1da177e4 LT |
1296 | c = __DISABLED_CHAR; |
1297 | goto handle_newline; | |
1298 | } | |
1299 | if ((c == EOL_CHAR(tty)) || | |
1300 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1301 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1302 | ? 1 : 0; | |
1303 | if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) { | |
7e94b1d9 JP |
1304 | if (L_ECHO(tty)) |
1305 | process_output('\a', tty); | |
acc71bba JP |
1306 | return; |
1307 | } | |
1da177e4 LT |
1308 | /* |
1309 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1310 | */ | |
1311 | if (L_ECHO(tty)) { | |
1da177e4 LT |
1312 | /* Record the column of first canon char. */ |
1313 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1314 | echo_set_canon_col(tty); |
1da177e4 | 1315 | echo_char(c, tty); |
a88a69c9 | 1316 | process_echoes(tty); |
1da177e4 LT |
1317 | } |
1318 | /* | |
1319 | * XXX does PARMRK doubling happen for | |
1320 | * EOL_CHAR and EOL2_CHAR? | |
1321 | */ | |
acc71bba | 1322 | if (parmrk) |
1da177e4 LT |
1323 | put_tty_queue(c, tty); |
1324 | ||
4edf1827 | 1325 | handle_newline: |
1da177e4 | 1326 | spin_lock_irqsave(&tty->read_lock, flags); |
3fe780b3 | 1327 | set_bit(tty->read_head, ldata->read_flags); |
1da177e4 LT |
1328 | put_tty_queue_nolock(c, tty); |
1329 | tty->canon_head = tty->read_head; | |
1330 | tty->canon_data++; | |
1331 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1332 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); | |
1333 | if (waitqueue_active(&tty->read_wait)) | |
1334 | wake_up_interruptible(&tty->read_wait); | |
1335 | return; | |
1336 | } | |
1337 | } | |
4edf1827 | 1338 | |
acc71bba JP |
1339 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
1340 | if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { | |
1341 | /* beep if no space */ | |
7e94b1d9 JP |
1342 | if (L_ECHO(tty)) |
1343 | process_output('\a', tty); | |
acc71bba JP |
1344 | return; |
1345 | } | |
1346 | if (L_ECHO(tty)) { | |
1347 | finish_erasing(tty); | |
1da177e4 | 1348 | if (c == '\n') |
a88a69c9 | 1349 | echo_char_raw('\n', tty); |
1da177e4 LT |
1350 | else { |
1351 | /* Record the column of first canon char. */ | |
1352 | if (tty->canon_head == tty->read_head) | |
a88a69c9 | 1353 | echo_set_canon_col(tty); |
1da177e4 LT |
1354 | echo_char(c, tty); |
1355 | } | |
a88a69c9 | 1356 | process_echoes(tty); |
1da177e4 LT |
1357 | } |
1358 | ||
acc71bba | 1359 | if (parmrk) |
1da177e4 LT |
1360 | put_tty_queue(c, tty); |
1361 | ||
1362 | put_tty_queue(c, tty); | |
4edf1827 | 1363 | } |
1da177e4 | 1364 | |
1da177e4 LT |
1365 | |
1366 | /** | |
1367 | * n_tty_write_wakeup - asynchronous I/O notifier | |
1368 | * @tty: tty device | |
1369 | * | |
1370 | * Required for the ptys, serial driver etc. since processes | |
1371 | * that attach themselves to the master and rely on ASYNC | |
1372 | * IO must be woken up | |
1373 | */ | |
1374 | ||
1375 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
1376 | { | |
ff8cb0fd | 1377 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) |
1da177e4 | 1378 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); |
1da177e4 LT |
1379 | } |
1380 | ||
1381 | /** | |
1382 | * n_tty_receive_buf - data receive | |
1383 | * @tty: terminal device | |
1384 | * @cp: buffer | |
1385 | * @fp: flag buffer | |
1386 | * @count: characters | |
1387 | * | |
1388 | * Called by the terminal driver when a block of characters has | |
1389 | * been received. This function must be called from soft contexts | |
1390 | * not from interrupt context. The driver is responsible for making | |
1391 | * calls one at a time and in order (or using flush_to_ldisc) | |
1392 | */ | |
4edf1827 | 1393 | |
55db4c64 LT |
1394 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1395 | char *fp, int count) | |
1da177e4 | 1396 | { |
53c5ee2c | 1397 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1398 | const unsigned char *p; |
1399 | char *f, flags = TTY_NORMAL; | |
1400 | int i; | |
1401 | char buf[64]; | |
1402 | unsigned long cpuflags; | |
1403 | ||
53c5ee2c | 1404 | if (ldata->real_raw) { |
1da177e4 LT |
1405 | spin_lock_irqsave(&tty->read_lock, cpuflags); |
1406 | i = min(N_TTY_BUF_SIZE - tty->read_cnt, | |
1407 | N_TTY_BUF_SIZE - tty->read_head); | |
1408 | i = min(count, i); | |
1409 | memcpy(tty->read_buf + tty->read_head, cp, i); | |
1410 | tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1411 | tty->read_cnt += i; | |
1412 | cp += i; | |
1413 | count -= i; | |
1414 | ||
1415 | i = min(N_TTY_BUF_SIZE - tty->read_cnt, | |
1416 | N_TTY_BUF_SIZE - tty->read_head); | |
1417 | i = min(count, i); | |
1418 | memcpy(tty->read_buf + tty->read_head, cp, i); | |
1419 | tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1420 | tty->read_cnt += i; | |
1421 | spin_unlock_irqrestore(&tty->read_lock, cpuflags); | |
1422 | } else { | |
4edf1827 | 1423 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1424 | if (f) |
1425 | flags = *f++; | |
1426 | switch (flags) { | |
1427 | case TTY_NORMAL: | |
1428 | n_tty_receive_char(tty, *p); | |
1429 | break; | |
1430 | case TTY_BREAK: | |
1431 | n_tty_receive_break(tty); | |
1432 | break; | |
1433 | case TTY_PARITY: | |
1434 | case TTY_FRAME: | |
1435 | n_tty_receive_parity_error(tty, *p); | |
1436 | break; | |
1437 | case TTY_OVERRUN: | |
1438 | n_tty_receive_overrun(tty); | |
1439 | break; | |
1440 | default: | |
4edf1827 | 1441 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1442 | tty_name(tty, buf), flags); |
1443 | break; | |
1444 | } | |
1445 | } | |
f34d7a5b AC |
1446 | if (tty->ops->flush_chars) |
1447 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1448 | } |
1449 | ||
55db4c64 LT |
1450 | n_tty_set_room(tty); |
1451 | ||
53c5ee2c | 1452 | if ((!ldata->icanon && (tty->read_cnt >= tty->minimum_to_wake)) || |
26df6d13 | 1453 | L_EXTPROC(tty)) { |
1da177e4 LT |
1454 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1455 | if (waitqueue_active(&tty->read_wait)) | |
1456 | wake_up_interruptible(&tty->read_wait); | |
1457 | } | |
1458 | ||
1459 | /* | |
1460 | * Check the remaining room for the input canonicalization | |
1461 | * mode. We don't want to throttle the driver if we're in | |
1462 | * canonical mode and don't have a newline yet! | |
1463 | */ | |
55db4c64 | 1464 | if (tty->receive_room < TTY_THRESHOLD_THROTTLE) |
39c2e60f | 1465 | tty_throttle(tty); |
0a44ab41 AC |
1466 | |
1467 | /* FIXME: there is a tiny race here if the receive room check runs | |
1468 | before the other work executes and empties the buffer (upping | |
1469 | the receiving room and unthrottling. We then throttle and get | |
1470 | stuck. This has been observed and traced down by Vincent Pillet/ | |
1471 | We need to address this when we sort out out the rx path locking */ | |
1da177e4 LT |
1472 | } |
1473 | ||
1474 | int is_ignored(int sig) | |
1475 | { | |
1476 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1477 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1478 | } |
1479 | ||
1480 | /** | |
1481 | * n_tty_set_termios - termios data changed | |
1482 | * @tty: terminal | |
1483 | * @old: previous data | |
1484 | * | |
1485 | * Called by the tty layer when the user changes termios flags so | |
1486 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1487 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1488 | * guaranteed that this function will not be re-entered or in progress |
1489 | * when the ldisc is closed. | |
17b82060 AC |
1490 | * |
1491 | * Locking: Caller holds tty->termios_mutex | |
1da177e4 | 1492 | */ |
4edf1827 AC |
1493 | |
1494 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1495 | { |
53c5ee2c | 1496 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1497 | int canon_change = 1; |
47afa7a5 AC |
1498 | |
1499 | if (old) | |
adc8d746 | 1500 | canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON; |
47afa7a5 | 1501 | if (canon_change) { |
3fe780b3 | 1502 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
47afa7a5 AC |
1503 | tty->canon_head = tty->read_tail; |
1504 | tty->canon_data = 0; | |
53c5ee2c | 1505 | ldata->erasing = 0; |
47afa7a5 AC |
1506 | } |
1507 | ||
1508 | if (canon_change && !L_ICANON(tty) && tty->read_cnt) | |
1509 | wake_up_interruptible(&tty->read_wait); | |
4edf1827 | 1510 | |
53c5ee2c | 1511 | ldata->icanon = (L_ICANON(tty) != 0); |
1da177e4 | 1512 | if (test_bit(TTY_HW_COOK_IN, &tty->flags)) { |
53c5ee2c JS |
1513 | ldata->raw = 1; |
1514 | ldata->real_raw = 1; | |
55db4c64 | 1515 | n_tty_set_room(tty); |
1da177e4 LT |
1516 | return; |
1517 | } | |
1518 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || | |
1519 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1520 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1521 | I_PARMRK(tty)) { | |
3fe780b3 | 1522 | bitmap_zero(ldata->process_char_map, 256); |
1da177e4 LT |
1523 | |
1524 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
3fe780b3 | 1525 | set_bit('\r', ldata->process_char_map); |
1da177e4 | 1526 | if (I_INLCR(tty)) |
3fe780b3 | 1527 | set_bit('\n', ldata->process_char_map); |
1da177e4 LT |
1528 | |
1529 | if (L_ICANON(tty)) { | |
3fe780b3 JS |
1530 | set_bit(ERASE_CHAR(tty), ldata->process_char_map); |
1531 | set_bit(KILL_CHAR(tty), ldata->process_char_map); | |
1532 | set_bit(EOF_CHAR(tty), ldata->process_char_map); | |
1533 | set_bit('\n', ldata->process_char_map); | |
1534 | set_bit(EOL_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1535 | if (L_IEXTEN(tty)) { |
1536 | set_bit(WERASE_CHAR(tty), | |
3fe780b3 | 1537 | ldata->process_char_map); |
1da177e4 | 1538 | set_bit(LNEXT_CHAR(tty), |
3fe780b3 | 1539 | ldata->process_char_map); |
1da177e4 | 1540 | set_bit(EOL2_CHAR(tty), |
3fe780b3 | 1541 | ldata->process_char_map); |
1da177e4 LT |
1542 | if (L_ECHO(tty)) |
1543 | set_bit(REPRINT_CHAR(tty), | |
3fe780b3 | 1544 | ldata->process_char_map); |
1da177e4 LT |
1545 | } |
1546 | } | |
1547 | if (I_IXON(tty)) { | |
3fe780b3 JS |
1548 | set_bit(START_CHAR(tty), ldata->process_char_map); |
1549 | set_bit(STOP_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1550 | } |
1551 | if (L_ISIG(tty)) { | |
3fe780b3 JS |
1552 | set_bit(INTR_CHAR(tty), ldata->process_char_map); |
1553 | set_bit(QUIT_CHAR(tty), ldata->process_char_map); | |
1554 | set_bit(SUSP_CHAR(tty), ldata->process_char_map); | |
1da177e4 | 1555 | } |
3fe780b3 | 1556 | clear_bit(__DISABLED_CHAR, ldata->process_char_map); |
53c5ee2c JS |
1557 | ldata->raw = 0; |
1558 | ldata->real_raw = 0; | |
1da177e4 | 1559 | } else { |
53c5ee2c | 1560 | ldata->raw = 1; |
1da177e4 LT |
1561 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1562 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1563 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1564 | ldata->real_raw = 1; |
1da177e4 | 1565 | else |
53c5ee2c | 1566 | ldata->real_raw = 0; |
1da177e4 | 1567 | } |
55db4c64 | 1568 | n_tty_set_room(tty); |
f34d7a5b AC |
1569 | /* The termios change make the tty ready for I/O */ |
1570 | wake_up_interruptible(&tty->write_wait); | |
1571 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1572 | } |
1573 | ||
1574 | /** | |
1575 | * n_tty_close - close the ldisc for this tty | |
1576 | * @tty: device | |
1577 | * | |
4edf1827 AC |
1578 | * Called from the terminal layer when this line discipline is |
1579 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1580 | * discipline change. The function will not be called while other |
1581 | * ldisc methods are in progress. | |
1582 | */ | |
4edf1827 | 1583 | |
1da177e4 LT |
1584 | static void n_tty_close(struct tty_struct *tty) |
1585 | { | |
70ece7a7 JS |
1586 | struct n_tty_data *ldata = tty->disc_data; |
1587 | ||
1da177e4 | 1588 | n_tty_flush_buffer(tty); |
b91939f5 JS |
1589 | kfree(tty->read_buf); |
1590 | kfree(tty->echo_buf); | |
70ece7a7 | 1591 | kfree(ldata); |
b91939f5 JS |
1592 | tty->read_buf = NULL; |
1593 | tty->echo_buf = NULL; | |
70ece7a7 | 1594 | tty->disc_data = NULL; |
1da177e4 LT |
1595 | } |
1596 | ||
1597 | /** | |
1598 | * n_tty_open - open an ldisc | |
1599 | * @tty: terminal to open | |
1600 | * | |
4edf1827 | 1601 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1602 | * terminal device. Can sleep. Called serialized so that no |
1603 | * other events will occur in parallel. No further open will occur | |
1604 | * until a close. | |
1605 | */ | |
1606 | ||
1607 | static int n_tty_open(struct tty_struct *tty) | |
1608 | { | |
70ece7a7 JS |
1609 | struct n_tty_data *ldata; |
1610 | ||
1611 | ldata = kzalloc(sizeof(*ldata), GFP_KERNEL); | |
1612 | if (!ldata) | |
1613 | goto err; | |
1614 | ||
53c5ee2c JS |
1615 | ldata->overrun_time = jiffies; |
1616 | ||
a88a69c9 | 1617 | /* These are ugly. Currently a malloc failure here can panic */ |
b91939f5 JS |
1618 | tty->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1619 | tty->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); | |
1620 | if (!tty->read_buf || !tty->echo_buf) | |
1621 | goto err_free_bufs; | |
0b4068a1 | 1622 | |
70ece7a7 | 1623 | tty->disc_data = ldata; |
1da177e4 | 1624 | reset_buffer_flags(tty); |
7b292b4b | 1625 | tty_unthrottle(tty); |
53c5ee2c | 1626 | ldata->column = 0; |
1da177e4 LT |
1627 | n_tty_set_termios(tty, NULL); |
1628 | tty->minimum_to_wake = 1; | |
1629 | tty->closing = 0; | |
70ece7a7 | 1630 | |
1da177e4 | 1631 | return 0; |
b91939f5 JS |
1632 | err_free_bufs: |
1633 | kfree(tty->read_buf); | |
1634 | kfree(tty->echo_buf); | |
70ece7a7 JS |
1635 | kfree(ldata); |
1636 | err: | |
b91939f5 | 1637 | return -ENOMEM; |
1da177e4 LT |
1638 | } |
1639 | ||
1640 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1641 | { | |
53c5ee2c JS |
1642 | struct n_tty_data *ldata = tty->disc_data; |
1643 | ||
e043e42b | 1644 | tty_flush_to_ldisc(tty); |
53c5ee2c | 1645 | if (ldata->icanon && !L_EXTPROC(tty)) { |
1da177e4 LT |
1646 | if (tty->canon_data) |
1647 | return 1; | |
1648 | } else if (tty->read_cnt >= (amt ? amt : 1)) | |
1649 | return 1; | |
1650 | ||
1651 | return 0; | |
1652 | } | |
1653 | ||
1654 | /** | |
bbd20759 | 1655 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1656 | * @tty: terminal device |
1657 | * @b: user data | |
1658 | * @nr: size of data | |
1659 | * | |
11a96d18 | 1660 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1661 | * ICANON is off; it copies characters straight from the tty queue to |
1662 | * user space directly. It can be profitably called twice; once to | |
1663 | * drain the space from the tail pointer to the (physical) end of the | |
1664 | * buffer, and once to drain the space from the (physical) beginning of | |
1665 | * the buffer to head pointer. | |
1666 | * | |
817d6d3b | 1667 | * Called under the tty->atomic_read_lock sem |
1da177e4 LT |
1668 | * |
1669 | */ | |
4edf1827 | 1670 | |
33f0f88f | 1671 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1672 | unsigned char __user **b, |
1673 | size_t *nr) | |
1674 | ||
1675 | { | |
53c5ee2c | 1676 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1677 | int retval; |
1678 | size_t n; | |
1679 | unsigned long flags; | |
3fa10cc8 | 1680 | bool is_eof; |
1da177e4 LT |
1681 | |
1682 | retval = 0; | |
1683 | spin_lock_irqsave(&tty->read_lock, flags); | |
1684 | n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail); | |
1685 | n = min(*nr, n); | |
1686 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1687 | if (n) { | |
1da177e4 LT |
1688 | retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n); |
1689 | n -= retval; | |
3fa10cc8 JS |
1690 | is_eof = n == 1 && |
1691 | tty->read_buf[tty->read_tail] == EOF_CHAR(tty); | |
6c633f27 | 1692 | tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n, |
53c5ee2c | 1693 | ldata->icanon); |
1da177e4 LT |
1694 | spin_lock_irqsave(&tty->read_lock, flags); |
1695 | tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1); | |
1696 | tty->read_cnt -= n; | |
26df6d13 | 1697 | /* Turn single EOF into zero-length read */ |
53c5ee2c | 1698 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !tty->read_cnt) |
3fa10cc8 | 1699 | n = 0; |
1da177e4 LT |
1700 | spin_unlock_irqrestore(&tty->read_lock, flags); |
1701 | *b += n; | |
1702 | *nr -= n; | |
1703 | } | |
1704 | return retval; | |
1705 | } | |
1706 | ||
cc4191dc | 1707 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1708 | size_t, loff_t *); |
1da177e4 LT |
1709 | |
1710 | /** | |
1711 | * job_control - check job control | |
1712 | * @tty: tty | |
1713 | * @file: file handle | |
1714 | * | |
1715 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1716 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1717 | * error code if action should be taken. |
04f378b1 AC |
1718 | * |
1719 | * FIXME: | |
1720 | * Locking: None - redirected write test is safe, testing | |
1721 | * current->signal should possibly lock current->sighand | |
1722 | * pgrp locking ? | |
1da177e4 | 1723 | */ |
4edf1827 | 1724 | |
1da177e4 LT |
1725 | static int job_control(struct tty_struct *tty, struct file *file) |
1726 | { | |
1727 | /* Job control check -- must be done at start and after | |
1728 | every sleep (POSIX.1 7.1.1.4). */ | |
1729 | /* NOTE: not yet done after every sleep pending a thorough | |
1730 | check of the logic of this change. -- jlc */ | |
1731 | /* don't stop on /dev/console */ | |
1732 | if (file->f_op->write != redirected_tty_write && | |
1733 | current->signal->tty == tty) { | |
ab521dc0 | 1734 | if (!tty->pgrp) |
11a96d18 | 1735 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); |
ab521dc0 | 1736 | else if (task_pgrp(current) != tty->pgrp) { |
1da177e4 | 1737 | if (is_ignored(SIGTTIN) || |
3e7cd6c4 | 1738 | is_current_pgrp_orphaned()) |
1da177e4 | 1739 | return -EIO; |
ab521dc0 | 1740 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); |
040b6362 | 1741 | set_thread_flag(TIF_SIGPENDING); |
1da177e4 LT |
1742 | return -ERESTARTSYS; |
1743 | } | |
1744 | } | |
1745 | return 0; | |
1746 | } | |
4edf1827 | 1747 | |
1da177e4 LT |
1748 | |
1749 | /** | |
11a96d18 | 1750 | * n_tty_read - read function for tty |
1da177e4 LT |
1751 | * @tty: tty device |
1752 | * @file: file object | |
1753 | * @buf: userspace buffer pointer | |
1754 | * @nr: size of I/O | |
1755 | * | |
1756 | * Perform reads for the line discipline. We are guaranteed that the | |
1757 | * line discipline will not be closed under us but we may get multiple | |
1758 | * parallel readers and must handle this ourselves. We may also get | |
1759 | * a hangup. Always called in user context, may sleep. | |
1760 | * | |
1761 | * This code must be sure never to sleep through a hangup. | |
1762 | */ | |
4edf1827 | 1763 | |
11a96d18 | 1764 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1765 | unsigned char __user *buf, size_t nr) |
1766 | { | |
53c5ee2c | 1767 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1768 | unsigned char __user *b = buf; |
1769 | DECLARE_WAITQUEUE(wait, current); | |
1770 | int c; | |
1771 | int minimum, time; | |
1772 | ssize_t retval = 0; | |
1773 | ssize_t size; | |
1774 | long timeout; | |
1775 | unsigned long flags; | |
04f378b1 | 1776 | int packet; |
1da177e4 LT |
1777 | |
1778 | do_it_again: | |
1da177e4 | 1779 | c = job_control(tty, file); |
4edf1827 | 1780 | if (c < 0) |
1da177e4 | 1781 | return c; |
4edf1827 | 1782 | |
1da177e4 LT |
1783 | minimum = time = 0; |
1784 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 1785 | if (!ldata->icanon) { |
1da177e4 LT |
1786 | time = (HZ / 10) * TIME_CHAR(tty); |
1787 | minimum = MIN_CHAR(tty); | |
1788 | if (minimum) { | |
1789 | if (time) | |
1790 | tty->minimum_to_wake = 1; | |
1791 | else if (!waitqueue_active(&tty->read_wait) || | |
1792 | (tty->minimum_to_wake > minimum)) | |
1793 | tty->minimum_to_wake = minimum; | |
1794 | } else { | |
1795 | timeout = 0; | |
1796 | if (time) { | |
1797 | timeout = time; | |
1798 | time = 0; | |
1799 | } | |
1800 | tty->minimum_to_wake = minimum = 1; | |
1801 | } | |
1802 | } | |
1803 | ||
1804 | /* | |
1805 | * Internal serialization of reads. | |
1806 | */ | |
1807 | if (file->f_flags & O_NONBLOCK) { | |
70522e12 | 1808 | if (!mutex_trylock(&tty->atomic_read_lock)) |
1da177e4 | 1809 | return -EAGAIN; |
4edf1827 | 1810 | } else { |
70522e12 | 1811 | if (mutex_lock_interruptible(&tty->atomic_read_lock)) |
1da177e4 LT |
1812 | return -ERESTARTSYS; |
1813 | } | |
04f378b1 | 1814 | packet = tty->packet; |
1da177e4 LT |
1815 | |
1816 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
1817 | while (nr) { |
1818 | /* First test for status change. */ | |
04f378b1 | 1819 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
1820 | unsigned char cs; |
1821 | if (b != buf) | |
1822 | break; | |
04f378b1 | 1823 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
1824 | cs = tty->link->ctrl_status; |
1825 | tty->link->ctrl_status = 0; | |
04f378b1 | 1826 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 1827 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
1828 | retval = -EFAULT; |
1829 | b--; | |
1830 | break; | |
1831 | } | |
1832 | nr--; | |
1833 | break; | |
1834 | } | |
1835 | /* This statement must be first before checking for input | |
1836 | so that any interrupt will set the state back to | |
1837 | TASK_RUNNING. */ | |
1838 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 1839 | |
1da177e4 LT |
1840 | if (((minimum - (b - buf)) < tty->minimum_to_wake) && |
1841 | ((minimum - (b - buf)) >= 1)) | |
1842 | tty->minimum_to_wake = (minimum - (b - buf)); | |
4edf1827 | 1843 | |
1da177e4 LT |
1844 | if (!input_available_p(tty, 0)) { |
1845 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
1846 | retval = -EIO; | |
1847 | break; | |
1848 | } | |
1849 | if (tty_hung_up_p(file)) | |
1850 | break; | |
1851 | if (!timeout) | |
1852 | break; | |
1853 | if (file->f_flags & O_NONBLOCK) { | |
1854 | retval = -EAGAIN; | |
1855 | break; | |
1856 | } | |
1857 | if (signal_pending(current)) { | |
1858 | retval = -ERESTARTSYS; | |
1859 | break; | |
1860 | } | |
55db4c64 LT |
1861 | /* FIXME: does n_tty_set_room need locking ? */ |
1862 | n_tty_set_room(tty); | |
1da177e4 | 1863 | timeout = schedule_timeout(timeout); |
1da177e4 LT |
1864 | continue; |
1865 | } | |
1866 | __set_current_state(TASK_RUNNING); | |
1867 | ||
1868 | /* Deal with packet mode. */ | |
04f378b1 | 1869 | if (packet && b == buf) { |
522ed776 | 1870 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
1871 | retval = -EFAULT; |
1872 | b--; | |
1873 | break; | |
1874 | } | |
1875 | nr--; | |
1876 | } | |
1877 | ||
53c5ee2c | 1878 | if (ldata->icanon && !L_EXTPROC(tty)) { |
1da177e4 | 1879 | /* N.B. avoid overrun if nr == 0 */ |
00aaae03 | 1880 | spin_lock_irqsave(&tty->read_lock, flags); |
1da177e4 | 1881 | while (nr && tty->read_cnt) { |
4edf1827 | 1882 | int eol; |
1da177e4 LT |
1883 | |
1884 | eol = test_and_clear_bit(tty->read_tail, | |
3fe780b3 | 1885 | ldata->read_flags); |
1da177e4 | 1886 | c = tty->read_buf[tty->read_tail]; |
1da177e4 LT |
1887 | tty->read_tail = ((tty->read_tail+1) & |
1888 | (N_TTY_BUF_SIZE-1)); | |
1889 | tty->read_cnt--; | |
1890 | if (eol) { | |
1891 | /* this test should be redundant: | |
1892 | * we shouldn't be reading data if | |
1893 | * canon_data is 0 | |
1894 | */ | |
1895 | if (--tty->canon_data < 0) | |
1896 | tty->canon_data = 0; | |
1897 | } | |
1898 | spin_unlock_irqrestore(&tty->read_lock, flags); | |
1899 | ||
1900 | if (!eol || (c != __DISABLED_CHAR)) { | |
522ed776 | 1901 | if (tty_put_user(tty, c, b++)) { |
1da177e4 LT |
1902 | retval = -EFAULT; |
1903 | b--; | |
00aaae03 | 1904 | spin_lock_irqsave(&tty->read_lock, flags); |
1da177e4 LT |
1905 | break; |
1906 | } | |
1907 | nr--; | |
1908 | } | |
522ed776 MT |
1909 | if (eol) { |
1910 | tty_audit_push(tty); | |
00aaae03 | 1911 | spin_lock_irqsave(&tty->read_lock, flags); |
1da177e4 | 1912 | break; |
522ed776 | 1913 | } |
00aaae03 | 1914 | spin_lock_irqsave(&tty->read_lock, flags); |
1da177e4 | 1915 | } |
00aaae03 | 1916 | spin_unlock_irqrestore(&tty->read_lock, flags); |
1da177e4 LT |
1917 | if (retval) |
1918 | break; | |
1919 | } else { | |
1920 | int uncopied; | |
04f378b1 AC |
1921 | /* The copy function takes the read lock and handles |
1922 | locking internally for this case */ | |
1da177e4 LT |
1923 | uncopied = copy_from_read_buf(tty, &b, &nr); |
1924 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
1925 | if (uncopied) { | |
1926 | retval = -EFAULT; | |
1927 | break; | |
1928 | } | |
1929 | } | |
1930 | ||
1931 | /* If there is enough space in the read buffer now, let the | |
1932 | * low-level driver know. We use n_tty_chars_in_buffer() to | |
1933 | * check the buffer, as it now knows about canonical mode. | |
1934 | * Otherwise, if the driver is throttled and the line is | |
1935 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
1936 | * we won't get any more characters. | |
1937 | */ | |
55db4c64 LT |
1938 | if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) { |
1939 | n_tty_set_room(tty); | |
1da177e4 | 1940 | check_unthrottle(tty); |
55db4c64 | 1941 | } |
1da177e4 LT |
1942 | |
1943 | if (b - buf >= minimum) | |
1944 | break; | |
1945 | if (time) | |
1946 | timeout = time; | |
1947 | } | |
70522e12 | 1948 | mutex_unlock(&tty->atomic_read_lock); |
1da177e4 LT |
1949 | remove_wait_queue(&tty->read_wait, &wait); |
1950 | ||
1951 | if (!waitqueue_active(&tty->read_wait)) | |
1952 | tty->minimum_to_wake = minimum; | |
1953 | ||
1954 | __set_current_state(TASK_RUNNING); | |
1955 | size = b - buf; | |
1956 | if (size) { | |
1957 | retval = size; | |
1958 | if (nr) | |
4edf1827 | 1959 | clear_bit(TTY_PUSH, &tty->flags); |
1da177e4 | 1960 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) |
bbd20759 | 1961 | goto do_it_again; |
1da177e4 | 1962 | |
55db4c64 | 1963 | n_tty_set_room(tty); |
1da177e4 LT |
1964 | return retval; |
1965 | } | |
1966 | ||
1967 | /** | |
11a96d18 | 1968 | * n_tty_write - write function for tty |
1da177e4 LT |
1969 | * @tty: tty device |
1970 | * @file: file object | |
1971 | * @buf: userspace buffer pointer | |
1972 | * @nr: size of I/O | |
1973 | * | |
a88a69c9 | 1974 | * Write function of the terminal device. This is serialized with |
1da177e4 | 1975 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
1976 | * and other such events. Since the receive code will echo characters, |
1977 | * thus calling driver write methods, the output_lock is used in | |
1978 | * the output processing functions called here as well as in the | |
1979 | * echo processing function to protect the column state and space | |
1980 | * left in the buffer. | |
1da177e4 LT |
1981 | * |
1982 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
1983 | * |
1984 | * Locking: output_lock to protect column state and space left | |
1985 | * (note that the process_output*() functions take this | |
1986 | * lock themselves) | |
1da177e4 | 1987 | */ |
4edf1827 | 1988 | |
11a96d18 | 1989 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 1990 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
1991 | { |
1992 | const unsigned char *b = buf; | |
1993 | DECLARE_WAITQUEUE(wait, current); | |
1994 | int c; | |
1995 | ssize_t retval = 0; | |
1996 | ||
1997 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
1998 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
1999 | retval = tty_check_change(tty); | |
2000 | if (retval) | |
2001 | return retval; | |
2002 | } | |
2003 | ||
a88a69c9 JP |
2004 | /* Write out any echoed characters that are still pending */ |
2005 | process_echoes(tty); | |
300a6204 | 2006 | |
1da177e4 LT |
2007 | add_wait_queue(&tty->write_wait, &wait); |
2008 | while (1) { | |
2009 | set_current_state(TASK_INTERRUPTIBLE); | |
2010 | if (signal_pending(current)) { | |
2011 | retval = -ERESTARTSYS; | |
2012 | break; | |
2013 | } | |
2014 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2015 | retval = -EIO; | |
2016 | break; | |
2017 | } | |
2018 | if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
2019 | while (nr > 0) { | |
a88a69c9 | 2020 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2021 | if (num < 0) { |
2022 | if (num == -EAGAIN) | |
2023 | break; | |
2024 | retval = num; | |
2025 | goto break_out; | |
2026 | } | |
2027 | b += num; | |
2028 | nr -= num; | |
2029 | if (nr == 0) | |
2030 | break; | |
2031 | c = *b; | |
a88a69c9 | 2032 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2033 | break; |
2034 | b++; nr--; | |
2035 | } | |
f34d7a5b AC |
2036 | if (tty->ops->flush_chars) |
2037 | tty->ops->flush_chars(tty); | |
1da177e4 | 2038 | } else { |
d6afe27b | 2039 | while (nr > 0) { |
f34d7a5b | 2040 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
2041 | if (c < 0) { |
2042 | retval = c; | |
2043 | goto break_out; | |
2044 | } | |
2045 | if (!c) | |
2046 | break; | |
2047 | b += c; | |
2048 | nr -= c; | |
1da177e4 | 2049 | } |
1da177e4 LT |
2050 | } |
2051 | if (!nr) | |
2052 | break; | |
2053 | if (file->f_flags & O_NONBLOCK) { | |
2054 | retval = -EAGAIN; | |
2055 | break; | |
2056 | } | |
2057 | schedule(); | |
2058 | } | |
2059 | break_out: | |
2060 | __set_current_state(TASK_RUNNING); | |
2061 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2062 | if (b - buf != nr && tty->fasync) |
2063 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
1da177e4 LT |
2064 | return (b - buf) ? b - buf : retval; |
2065 | } | |
2066 | ||
2067 | /** | |
11a96d18 | 2068 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2069 | * @tty: terminal device |
2070 | * @file: file accessing it | |
2071 | * @wait: poll table | |
2072 | * | |
2073 | * Called when the line discipline is asked to poll() for data or | |
2074 | * for special events. This code is not serialized with respect to | |
2075 | * other events save open/close. | |
2076 | * | |
2077 | * This code must be sure never to sleep through a hangup. | |
2078 | * Called without the kernel lock held - fine | |
1da177e4 | 2079 | */ |
4edf1827 | 2080 | |
11a96d18 | 2081 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2082 | poll_table *wait) |
1da177e4 LT |
2083 | { |
2084 | unsigned int mask = 0; | |
2085 | ||
2086 | poll_wait(file, &tty->read_wait, wait); | |
2087 | poll_wait(file, &tty->write_wait, wait); | |
2088 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2089 | mask |= POLLIN | POLLRDNORM; | |
2090 | if (tty->packet && tty->link->ctrl_status) | |
2091 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2092 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2093 | mask |= POLLHUP; | |
2094 | if (tty_hung_up_p(file)) | |
2095 | mask |= POLLHUP; | |
2096 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2097 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
2098 | tty->minimum_to_wake = MIN_CHAR(tty); | |
2099 | else | |
2100 | tty->minimum_to_wake = 1; | |
2101 | } | |
f34d7a5b AC |
2102 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2103 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2104 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2105 | mask |= POLLOUT | POLLWRNORM; |
2106 | return mask; | |
2107 | } | |
2108 | ||
47afa7a5 AC |
2109 | static unsigned long inq_canon(struct tty_struct *tty) |
2110 | { | |
3fe780b3 | 2111 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2112 | int nr, head, tail; |
2113 | ||
17b82060 | 2114 | if (!tty->canon_data) |
47afa7a5 AC |
2115 | return 0; |
2116 | head = tty->canon_head; | |
2117 | tail = tty->read_tail; | |
2118 | nr = (head - tail) & (N_TTY_BUF_SIZE-1); | |
2119 | /* Skip EOF-chars.. */ | |
2120 | while (head != tail) { | |
3fe780b3 | 2121 | if (test_bit(tail, ldata->read_flags) && |
47afa7a5 AC |
2122 | tty->read_buf[tail] == __DISABLED_CHAR) |
2123 | nr--; | |
2124 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
2125 | } | |
2126 | return nr; | |
2127 | } | |
2128 | ||
2129 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2130 | unsigned int cmd, unsigned long arg) | |
2131 | { | |
2132 | int retval; | |
2133 | ||
2134 | switch (cmd) { | |
2135 | case TIOCOUTQ: | |
2136 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2137 | case TIOCINQ: | |
17b82060 | 2138 | /* FIXME: Locking */ |
47afa7a5 AC |
2139 | retval = tty->read_cnt; |
2140 | if (L_ICANON(tty)) | |
2141 | retval = inq_canon(tty); | |
2142 | return put_user(retval, (unsigned int __user *) arg); | |
2143 | default: | |
2144 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2145 | } | |
2146 | } | |
2147 | ||
a352def2 | 2148 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2149 | .magic = TTY_LDISC_MAGIC, |
2150 | .name = "n_tty", | |
2151 | .open = n_tty_open, | |
2152 | .close = n_tty_close, | |
2153 | .flush_buffer = n_tty_flush_buffer, | |
2154 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2155 | .read = n_tty_read, |
2156 | .write = n_tty_write, | |
e10cc1df PF |
2157 | .ioctl = n_tty_ioctl, |
2158 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2159 | .poll = n_tty_poll, |
e10cc1df PF |
2160 | .receive_buf = n_tty_receive_buf, |
2161 | .write_wakeup = n_tty_write_wakeup | |
1da177e4 | 2162 | }; |
572b9adb RG |
2163 | |
2164 | /** | |
2165 | * n_tty_inherit_ops - inherit N_TTY methods | |
2166 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2167 | * | |
2168 | * Used by a generic struct tty_ldisc_ops to easily inherit N_TTY | |
2169 | * methods. | |
2170 | */ | |
2171 | ||
2172 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2173 | { | |
2174 | *ops = tty_ldisc_N_TTY; | |
2175 | ops->owner = NULL; | |
2176 | ops->refcount = ops->flags = 0; | |
2177 | } | |
2178 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |