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; | |
f6c8dbe6 | 92 | int minimum_to_wake; |
ba2e68ac JS |
93 | |
94 | unsigned char *echo_buf; | |
95 | unsigned int echo_pos; | |
96 | unsigned int echo_cnt; | |
97 | ||
98 | int canon_data; | |
99 | unsigned long canon_head; | |
100 | unsigned int canon_column; | |
bddc7152 JS |
101 | |
102 | struct mutex atomic_read_lock; | |
103 | struct mutex output_lock; | |
104 | struct mutex echo_lock; | |
98001214 | 105 | raw_spinlock_t read_lock; |
70ece7a7 JS |
106 | }; |
107 | ||
522ed776 MT |
108 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
109 | unsigned char __user *ptr) | |
110 | { | |
53c5ee2c JS |
111 | struct n_tty_data *ldata = tty->disc_data; |
112 | ||
113 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
114 | return put_user(x, ptr); |
115 | } | |
116 | ||
55db4c64 | 117 | /** |
b8483052 | 118 | * n_tty_set_room - receive space |
55db4c64 LT |
119 | * @tty: terminal |
120 | * | |
7879a9f9 | 121 | * Updates tty->receive_room to reflect the currently available space |
b8483052 PH |
122 | * in the input buffer, and re-schedules the flip buffer work if space |
123 | * just became available. | |
124 | * | |
125 | * Locks: Concurrent update is protected with read_lock | |
55db4c64 LT |
126 | */ |
127 | ||
7879a9f9 | 128 | static int set_room(struct tty_struct *tty) |
55db4c64 | 129 | { |
53c5ee2c | 130 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 131 | int left; |
55db4c64 | 132 | int old_left; |
b8483052 PH |
133 | unsigned long flags; |
134 | ||
135 | raw_spin_lock_irqsave(&ldata->read_lock, flags); | |
55db4c64 | 136 | |
090abf7b JA |
137 | if (I_PARMRK(tty)) { |
138 | /* Multiply read_cnt by 3, since each byte might take up to | |
139 | * three times as many spaces when PARMRK is set (depending on | |
140 | * its flags, e.g. parity error). */ | |
ba2e68ac | 141 | left = N_TTY_BUF_SIZE - ldata->read_cnt * 3 - 1; |
090abf7b | 142 | } else |
ba2e68ac | 143 | left = N_TTY_BUF_SIZE - ldata->read_cnt - 1; |
090abf7b | 144 | |
55db4c64 LT |
145 | /* |
146 | * If we are doing input canonicalization, and there are no | |
147 | * pending newlines, let characters through without limit, so | |
148 | * that erase characters will be handled. Other excess | |
149 | * characters will be beeped. | |
150 | */ | |
151 | if (left <= 0) | |
ba2e68ac | 152 | left = ldata->icanon && !ldata->canon_data; |
55db4c64 LT |
153 | old_left = tty->receive_room; |
154 | tty->receive_room = left; | |
155 | ||
b8483052 PH |
156 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
157 | ||
7879a9f9 PH |
158 | return left && !old_left; |
159 | } | |
160 | ||
161 | static void n_tty_set_room(struct tty_struct *tty) | |
162 | { | |
55db4c64 | 163 | /* Did this open up the receive buffer? We may need to flip */ |
7879a9f9 | 164 | if (set_room(tty)) { |
ecbbfd44 | 165 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 166 | "scheduling with invalid itty\n"); |
21622939 PH |
167 | /* see if ldisc has been killed - if so, this means that |
168 | * even though the ldisc has been halted and ->buf.work | |
169 | * cancelled, ->buf.work is about to be rescheduled | |
170 | */ | |
171 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
172 | "scheduling buffer work for halted ldisc\n"); | |
ecbbfd44 JS |
173 | schedule_work(&tty->port->buf.work); |
174 | } | |
55db4c64 LT |
175 | } |
176 | ||
57c94121 | 177 | static void put_tty_queue_nolock(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 178 | { |
ba2e68ac JS |
179 | if (ldata->read_cnt < N_TTY_BUF_SIZE) { |
180 | ldata->read_buf[ldata->read_head] = c; | |
181 | ldata->read_head = (ldata->read_head + 1) & (N_TTY_BUF_SIZE-1); | |
182 | ldata->read_cnt++; | |
1da177e4 LT |
183 | } |
184 | } | |
185 | ||
17b82060 AC |
186 | /** |
187 | * put_tty_queue - add character to tty | |
188 | * @c: character | |
57c94121 | 189 | * @ldata: n_tty data |
17b82060 AC |
190 | * |
191 | * Add a character to the tty read_buf queue. This is done under the | |
192 | * read_lock to serialize character addition and also to protect us | |
193 | * against parallel reads or flushes | |
194 | */ | |
195 | ||
57c94121 | 196 | static void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 LT |
197 | { |
198 | unsigned long flags; | |
199 | /* | |
200 | * The problem of stomping on the buffers ends here. | |
201 | * Why didn't anyone see this one coming? --AJK | |
202 | */ | |
98001214 | 203 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
57c94121 | 204 | put_tty_queue_nolock(c, ldata); |
98001214 | 205 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
206 | } |
207 | ||
1da177e4 LT |
208 | /** |
209 | * reset_buffer_flags - reset buffer state | |
210 | * @tty: terminal to reset | |
211 | * | |
25518c68 PH |
212 | * Reset the read buffer counters and clear the flags. |
213 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 AC |
214 | * |
215 | * Locking: tty_read_lock for read fields. | |
1da177e4 | 216 | */ |
a88a69c9 | 217 | |
b66f4fa5 | 218 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 LT |
219 | { |
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); |
1da177e4 LT |
232 | } |
233 | ||
a30737ab PH |
234 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
235 | { | |
236 | unsigned long flags; | |
237 | ||
238 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
239 | if (tty->link->packet) { | |
240 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
241 | wake_up_interruptible(&tty->link->read_wait); | |
242 | } | |
243 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
244 | } | |
245 | ||
1da177e4 LT |
246 | /** |
247 | * n_tty_flush_buffer - clean input queue | |
248 | * @tty: terminal device | |
249 | * | |
25518c68 PH |
250 | * Flush the input buffer. Called when the tty layer wants the |
251 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
252 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 253 | * |
17b82060 | 254 | * Locking: ctrl_lock, read_lock. |
1da177e4 | 255 | */ |
4edf1827 AC |
256 | |
257 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 258 | { |
b66f4fa5 PH |
259 | reset_buffer_flags(tty->disc_data); |
260 | n_tty_set_room(tty); | |
4edf1827 | 261 | |
a30737ab PH |
262 | if (tty->link) |
263 | n_tty_packet_mode_flush(tty); | |
1da177e4 LT |
264 | } |
265 | ||
266 | /** | |
267 | * n_tty_chars_in_buffer - report available bytes | |
268 | * @tty: tty device | |
269 | * | |
270 | * Report the number of characters buffered to be delivered to user | |
4edf1827 | 271 | * at this instant in time. |
17b82060 AC |
272 | * |
273 | * Locking: read_lock | |
1da177e4 | 274 | */ |
4edf1827 | 275 | |
1da177e4 LT |
276 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
277 | { | |
53c5ee2c | 278 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
279 | unsigned long flags; |
280 | ssize_t n = 0; | |
281 | ||
98001214 | 282 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
53c5ee2c | 283 | if (!ldata->icanon) { |
ba2e68ac JS |
284 | n = ldata->read_cnt; |
285 | } else if (ldata->canon_data) { | |
286 | n = (ldata->canon_head > ldata->read_tail) ? | |
287 | ldata->canon_head - ldata->read_tail : | |
288 | ldata->canon_head + (N_TTY_BUF_SIZE - ldata->read_tail); | |
1da177e4 | 289 | } |
98001214 | 290 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
291 | return n; |
292 | } | |
293 | ||
294 | /** | |
295 | * is_utf8_continuation - utf8 multibyte check | |
296 | * @c: byte to check | |
297 | * | |
298 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
299 | * character. We use this to correctly compute the on screen size | |
300 | * of the character when printing | |
301 | */ | |
4edf1827 | 302 | |
1da177e4 LT |
303 | static inline int is_utf8_continuation(unsigned char c) |
304 | { | |
305 | return (c & 0xc0) == 0x80; | |
306 | } | |
307 | ||
308 | /** | |
309 | * is_continuation - multibyte check | |
310 | * @c: byte to check | |
311 | * | |
312 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
313 | * character and the terminal is in unicode mode. | |
314 | */ | |
4edf1827 | 315 | |
1da177e4 LT |
316 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
317 | { | |
318 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
319 | } | |
320 | ||
321 | /** | |
a88a69c9 | 322 | * do_output_char - output one character |
1da177e4 LT |
323 | * @c: character (or partial unicode symbol) |
324 | * @tty: terminal device | |
a88a69c9 | 325 | * @space: space available in tty driver write buffer |
1da177e4 | 326 | * |
a88a69c9 JP |
327 | * This is a helper function that handles one output character |
328 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
329 | * doing OPOST processing and putting the results in the |
330 | * tty driver's write buffer. | |
a88a69c9 JP |
331 | * |
332 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
333 | * and NLDLY. They simply aren't relevant in the world today. | |
334 | * If you ever need them, add them here. | |
1da177e4 | 335 | * |
a88a69c9 JP |
336 | * Returns the number of bytes of buffer space used or -1 if |
337 | * no space left. | |
338 | * | |
339 | * Locking: should be called under the output_lock to protect | |
340 | * the column state and space left in the buffer | |
1da177e4 | 341 | */ |
4edf1827 | 342 | |
a88a69c9 | 343 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 344 | { |
53c5ee2c | 345 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 346 | int spaces; |
1da177e4 | 347 | |
1da177e4 LT |
348 | if (!space) |
349 | return -1; | |
300a6204 | 350 | |
a88a69c9 JP |
351 | switch (c) { |
352 | case '\n': | |
353 | if (O_ONLRET(tty)) | |
53c5ee2c | 354 | ldata->column = 0; |
a88a69c9 JP |
355 | if (O_ONLCR(tty)) { |
356 | if (space < 2) | |
357 | return -1; | |
ba2e68ac | 358 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 359 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
360 | return 2; |
361 | } | |
ba2e68ac | 362 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
363 | break; |
364 | case '\r': | |
53c5ee2c | 365 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
366 | return 0; |
367 | if (O_OCRNL(tty)) { | |
368 | c = '\n'; | |
369 | if (O_ONLRET(tty)) | |
ba2e68ac | 370 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 371 | break; |
a88a69c9 | 372 | } |
ba2e68ac | 373 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
374 | break; |
375 | case '\t': | |
53c5ee2c | 376 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
377 | if (O_TABDLY(tty) == XTABS) { |
378 | if (space < spaces) | |
379 | return -1; | |
53c5ee2c | 380 | ldata->column += spaces; |
a88a69c9 JP |
381 | tty->ops->write(tty, " ", spaces); |
382 | return spaces; | |
1da177e4 | 383 | } |
53c5ee2c | 384 | ldata->column += spaces; |
a88a69c9 JP |
385 | break; |
386 | case '\b': | |
53c5ee2c JS |
387 | if (ldata->column > 0) |
388 | ldata->column--; | |
a88a69c9 JP |
389 | break; |
390 | default: | |
a59c0d6f JP |
391 | if (!iscntrl(c)) { |
392 | if (O_OLCUC(tty)) | |
393 | c = toupper(c); | |
394 | if (!is_continuation(c, tty)) | |
53c5ee2c | 395 | ldata->column++; |
a59c0d6f | 396 | } |
a88a69c9 | 397 | break; |
1da177e4 | 398 | } |
a88a69c9 | 399 | |
f34d7a5b | 400 | tty_put_char(tty, c); |
a88a69c9 JP |
401 | return 1; |
402 | } | |
403 | ||
404 | /** | |
405 | * process_output - output post processor | |
406 | * @c: character (or partial unicode symbol) | |
407 | * @tty: terminal device | |
408 | * | |
ee5aa7b8 JP |
409 | * Output one character with OPOST processing. |
410 | * Returns -1 when the output device is full and the character | |
411 | * must be retried. | |
a88a69c9 JP |
412 | * |
413 | * Locking: output_lock to protect column state and space left | |
414 | * (also, this is called from n_tty_write under the | |
415 | * tty layer write lock) | |
416 | */ | |
417 | ||
418 | static int process_output(unsigned char c, struct tty_struct *tty) | |
419 | { | |
bddc7152 | 420 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
421 | int space, retval; |
422 | ||
bddc7152 | 423 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
424 | |
425 | space = tty_write_room(tty); | |
426 | retval = do_output_char(c, tty, space); | |
427 | ||
bddc7152 | 428 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
429 | if (retval < 0) |
430 | return -1; | |
431 | else | |
432 | return 0; | |
1da177e4 LT |
433 | } |
434 | ||
435 | /** | |
a88a69c9 | 436 | * process_output_block - block post processor |
1da177e4 | 437 | * @tty: terminal device |
ee5aa7b8 JP |
438 | * @buf: character buffer |
439 | * @nr: number of bytes to output | |
440 | * | |
441 | * Output a block of characters with OPOST processing. | |
442 | * Returns the number of characters output. | |
1da177e4 LT |
443 | * |
444 | * This path is used to speed up block console writes, among other | |
445 | * things when processing blocks of output data. It handles only | |
446 | * the simple cases normally found and helps to generate blocks of | |
447 | * symbols for the console driver and thus improve performance. | |
448 | * | |
a88a69c9 JP |
449 | * Locking: output_lock to protect column state and space left |
450 | * (also, this is called from n_tty_write under the | |
451 | * tty layer write lock) | |
1da177e4 | 452 | */ |
4edf1827 | 453 | |
a88a69c9 JP |
454 | static ssize_t process_output_block(struct tty_struct *tty, |
455 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 456 | { |
53c5ee2c | 457 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 458 | int space; |
bbd20759 | 459 | int i; |
1da177e4 LT |
460 | const unsigned char *cp; |
461 | ||
bddc7152 | 462 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 463 | |
f34d7a5b | 464 | space = tty_write_room(tty); |
300a6204 | 465 | if (!space) { |
bddc7152 | 466 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 467 | return 0; |
a88a69c9 | 468 | } |
1da177e4 LT |
469 | if (nr > space) |
470 | nr = space; | |
471 | ||
472 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
473 | unsigned char c = *cp; |
474 | ||
475 | switch (c) { | |
1da177e4 LT |
476 | case '\n': |
477 | if (O_ONLRET(tty)) | |
53c5ee2c | 478 | ldata->column = 0; |
1da177e4 LT |
479 | if (O_ONLCR(tty)) |
480 | goto break_out; | |
ba2e68ac | 481 | ldata->canon_column = ldata->column; |
1da177e4 LT |
482 | break; |
483 | case '\r': | |
53c5ee2c | 484 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
485 | goto break_out; |
486 | if (O_OCRNL(tty)) | |
487 | goto break_out; | |
ba2e68ac | 488 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
489 | break; |
490 | case '\t': | |
491 | goto break_out; | |
492 | case '\b': | |
53c5ee2c JS |
493 | if (ldata->column > 0) |
494 | ldata->column--; | |
1da177e4 LT |
495 | break; |
496 | default: | |
a59c0d6f JP |
497 | if (!iscntrl(c)) { |
498 | if (O_OLCUC(tty)) | |
499 | goto break_out; | |
500 | if (!is_continuation(c, tty)) | |
53c5ee2c | 501 | ldata->column++; |
a59c0d6f | 502 | } |
1da177e4 LT |
503 | break; |
504 | } | |
505 | } | |
506 | break_out: | |
f34d7a5b | 507 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 508 | |
bddc7152 | 509 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
510 | return i; |
511 | } | |
512 | ||
a88a69c9 JP |
513 | /** |
514 | * process_echoes - write pending echo characters | |
515 | * @tty: terminal device | |
516 | * | |
517 | * Write previously buffered echo (and other ldisc-generated) | |
518 | * characters to the tty. | |
519 | * | |
520 | * Characters generated by the ldisc (including echoes) need to | |
521 | * be buffered because the driver's write buffer can fill during | |
522 | * heavy program output. Echoing straight to the driver will | |
523 | * often fail under these conditions, causing lost characters and | |
524 | * resulting mismatches of ldisc state information. | |
525 | * | |
526 | * Since the ldisc state must represent the characters actually sent | |
527 | * to the driver at the time of the write, operations like certain | |
528 | * changes in column state are also saved in the buffer and executed | |
529 | * here. | |
530 | * | |
531 | * A circular fifo buffer is used so that the most recent characters | |
532 | * are prioritized. Also, when control characters are echoed with a | |
533 | * prefixed "^", the pair is treated atomically and thus not separated. | |
534 | * | |
535 | * Locking: output_lock to protect column state and space left, | |
536 | * echo_lock to protect the echo buffer | |
537 | */ | |
538 | ||
539 | static void process_echoes(struct tty_struct *tty) | |
540 | { | |
53c5ee2c | 541 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
542 | int space, nr; |
543 | unsigned char c; | |
544 | unsigned char *cp, *buf_end; | |
545 | ||
ba2e68ac | 546 | if (!ldata->echo_cnt) |
a88a69c9 JP |
547 | return; |
548 | ||
bddc7152 JS |
549 | mutex_lock(&ldata->output_lock); |
550 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
551 | |
552 | space = tty_write_room(tty); | |
553 | ||
ba2e68ac JS |
554 | buf_end = ldata->echo_buf + N_TTY_BUF_SIZE; |
555 | cp = ldata->echo_buf + ldata->echo_pos; | |
556 | nr = ldata->echo_cnt; | |
a88a69c9 JP |
557 | while (nr > 0) { |
558 | c = *cp; | |
559 | if (c == ECHO_OP_START) { | |
560 | unsigned char op; | |
561 | unsigned char *opp; | |
562 | int no_space_left = 0; | |
563 | ||
564 | /* | |
565 | * If the buffer byte is the start of a multi-byte | |
566 | * operation, get the next byte, which is either the | |
567 | * op code or a control character value. | |
568 | */ | |
569 | opp = cp + 1; | |
570 | if (opp == buf_end) | |
571 | opp -= N_TTY_BUF_SIZE; | |
572 | op = *opp; | |
300a6204 | 573 | |
a88a69c9 JP |
574 | switch (op) { |
575 | unsigned int num_chars, num_bs; | |
576 | ||
577 | case ECHO_OP_ERASE_TAB: | |
578 | if (++opp == buf_end) | |
579 | opp -= N_TTY_BUF_SIZE; | |
580 | num_chars = *opp; | |
581 | ||
582 | /* | |
583 | * Determine how many columns to go back | |
584 | * in order to erase the tab. | |
585 | * This depends on the number of columns | |
586 | * used by other characters within the tab | |
587 | * area. If this (modulo 8) count is from | |
588 | * the start of input rather than from a | |
589 | * previous tab, we offset by canon column. | |
590 | * Otherwise, tab spacing is normal. | |
591 | */ | |
592 | if (!(num_chars & 0x80)) | |
ba2e68ac | 593 | num_chars += ldata->canon_column; |
a88a69c9 JP |
594 | num_bs = 8 - (num_chars & 7); |
595 | ||
596 | if (num_bs > space) { | |
597 | no_space_left = 1; | |
598 | break; | |
599 | } | |
600 | space -= num_bs; | |
601 | while (num_bs--) { | |
602 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
603 | if (ldata->column > 0) |
604 | ldata->column--; | |
a88a69c9 JP |
605 | } |
606 | cp += 3; | |
607 | nr -= 3; | |
608 | break; | |
609 | ||
610 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 611 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
612 | cp += 2; |
613 | nr -= 2; | |
614 | break; | |
615 | ||
616 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
617 | if (ldata->column > 0) |
618 | ldata->column--; | |
a88a69c9 JP |
619 | cp += 2; |
620 | nr -= 2; | |
621 | break; | |
622 | ||
623 | case ECHO_OP_START: | |
624 | /* This is an escaped echo op start code */ | |
625 | if (!space) { | |
626 | no_space_left = 1; | |
627 | break; | |
628 | } | |
629 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 630 | ldata->column++; |
a88a69c9 JP |
631 | space--; |
632 | cp += 2; | |
633 | nr -= 2; | |
634 | break; | |
635 | ||
636 | default: | |
a88a69c9 | 637 | /* |
62b26358 JP |
638 | * If the op is not a special byte code, |
639 | * it is a ctrl char tagged to be echoed | |
640 | * as "^X" (where X is the letter | |
641 | * representing the control char). | |
642 | * Note that we must ensure there is | |
643 | * enough space for the whole ctrl pair. | |
644 | * | |
a88a69c9 | 645 | */ |
62b26358 JP |
646 | if (space < 2) { |
647 | no_space_left = 1; | |
648 | break; | |
649 | } | |
650 | tty_put_char(tty, '^'); | |
651 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 652 | ldata->column += 2; |
62b26358 | 653 | space -= 2; |
a88a69c9 JP |
654 | cp += 2; |
655 | nr -= 2; | |
656 | } | |
657 | ||
658 | if (no_space_left) | |
659 | break; | |
660 | } else { | |
582f5590 | 661 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
662 | int retval = do_output_char(c, tty, space); |
663 | if (retval < 0) | |
664 | break; | |
665 | space -= retval; | |
666 | } else { | |
667 | if (!space) | |
668 | break; | |
669 | tty_put_char(tty, c); | |
670 | space -= 1; | |
671 | } | |
a88a69c9 JP |
672 | cp += 1; |
673 | nr -= 1; | |
674 | } | |
675 | ||
676 | /* When end of circular buffer reached, wrap around */ | |
677 | if (cp >= buf_end) | |
678 | cp -= N_TTY_BUF_SIZE; | |
679 | } | |
680 | ||
681 | if (nr == 0) { | |
ba2e68ac JS |
682 | ldata->echo_pos = 0; |
683 | ldata->echo_cnt = 0; | |
53c5ee2c | 684 | ldata->echo_overrun = 0; |
a88a69c9 | 685 | } else { |
ba2e68ac JS |
686 | int num_processed = ldata->echo_cnt - nr; |
687 | ldata->echo_pos += num_processed; | |
688 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; | |
689 | ldata->echo_cnt = nr; | |
a88a69c9 | 690 | if (num_processed > 0) |
53c5ee2c | 691 | ldata->echo_overrun = 0; |
a88a69c9 JP |
692 | } |
693 | ||
bddc7152 JS |
694 | mutex_unlock(&ldata->echo_lock); |
695 | mutex_unlock(&ldata->output_lock); | |
a88a69c9 JP |
696 | |
697 | if (tty->ops->flush_chars) | |
698 | tty->ops->flush_chars(tty); | |
699 | } | |
700 | ||
701 | /** | |
702 | * add_echo_byte - add a byte to the echo buffer | |
703 | * @c: unicode byte to echo | |
57c94121 | 704 | * @ldata: n_tty data |
a88a69c9 JP |
705 | * |
706 | * Add a character or operation byte to the echo buffer. | |
707 | * | |
708 | * Should be called under the echo lock to protect the echo buffer. | |
709 | */ | |
710 | ||
57c94121 | 711 | static void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 JP |
712 | { |
713 | int new_byte_pos; | |
714 | ||
ba2e68ac | 715 | if (ldata->echo_cnt == N_TTY_BUF_SIZE) { |
a88a69c9 | 716 | /* Circular buffer is already at capacity */ |
ba2e68ac | 717 | new_byte_pos = ldata->echo_pos; |
a88a69c9 JP |
718 | |
719 | /* | |
720 | * Since the buffer start position needs to be advanced, | |
721 | * be sure to step by a whole operation byte group. | |
722 | */ | |
ba2e68ac JS |
723 | if (ldata->echo_buf[ldata->echo_pos] == ECHO_OP_START) { |
724 | if (ldata->echo_buf[(ldata->echo_pos + 1) & | |
a88a69c9 JP |
725 | (N_TTY_BUF_SIZE - 1)] == |
726 | ECHO_OP_ERASE_TAB) { | |
ba2e68ac JS |
727 | ldata->echo_pos += 3; |
728 | ldata->echo_cnt -= 2; | |
a88a69c9 | 729 | } else { |
ba2e68ac JS |
730 | ldata->echo_pos += 2; |
731 | ldata->echo_cnt -= 1; | |
a88a69c9 JP |
732 | } |
733 | } else { | |
ba2e68ac | 734 | ldata->echo_pos++; |
a88a69c9 | 735 | } |
ba2e68ac | 736 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; |
a88a69c9 | 737 | |
53c5ee2c | 738 | ldata->echo_overrun = 1; |
a88a69c9 | 739 | } else { |
ba2e68ac | 740 | new_byte_pos = ldata->echo_pos + ldata->echo_cnt; |
a88a69c9 | 741 | new_byte_pos &= N_TTY_BUF_SIZE - 1; |
ba2e68ac | 742 | ldata->echo_cnt++; |
a88a69c9 JP |
743 | } |
744 | ||
ba2e68ac | 745 | ldata->echo_buf[new_byte_pos] = c; |
a88a69c9 JP |
746 | } |
747 | ||
748 | /** | |
749 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 750 | * @ldata: n_tty data |
a88a69c9 JP |
751 | * |
752 | * Add an operation to the echo buffer to move back one column. | |
753 | * | |
754 | * Locking: echo_lock to protect the echo buffer | |
755 | */ | |
756 | ||
57c94121 | 757 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 758 | { |
bddc7152 | 759 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
760 | add_echo_byte(ECHO_OP_START, ldata); |
761 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
bddc7152 | 762 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
763 | } |
764 | ||
765 | /** | |
766 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 767 | * @ldata: n_tty data |
a88a69c9 JP |
768 | * |
769 | * Add an operation to the echo buffer to set the canon column | |
770 | * to the current column. | |
771 | * | |
772 | * Locking: echo_lock to protect the echo buffer | |
773 | */ | |
774 | ||
57c94121 | 775 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 776 | { |
bddc7152 | 777 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
778 | add_echo_byte(ECHO_OP_START, ldata); |
779 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
bddc7152 | 780 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
781 | } |
782 | ||
783 | /** | |
784 | * echo_erase_tab - add operation to erase a tab | |
785 | * @num_chars: number of character columns already used | |
786 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 787 | * @ldata: n_tty data |
a88a69c9 JP |
788 | * |
789 | * Add an operation to the echo buffer to erase a tab. | |
790 | * | |
791 | * Called by the eraser function, which knows how many character | |
792 | * columns have been used since either a previous tab or the start | |
793 | * of input. This information will be used later, along with | |
794 | * canon column (if applicable), to go back the correct number | |
795 | * of columns. | |
796 | * | |
797 | * Locking: echo_lock to protect the echo buffer | |
798 | */ | |
799 | ||
800 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 801 | struct n_tty_data *ldata) |
a88a69c9 | 802 | { |
bddc7152 | 803 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 804 | |
57c94121 JS |
805 | add_echo_byte(ECHO_OP_START, ldata); |
806 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
807 | |
808 | /* We only need to know this modulo 8 (tab spacing) */ | |
809 | num_chars &= 7; | |
810 | ||
811 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
812 | if (after_tab) | |
813 | num_chars |= 0x80; | |
300a6204 | 814 | |
57c94121 | 815 | add_echo_byte(num_chars, ldata); |
a88a69c9 | 816 | |
bddc7152 | 817 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
818 | } |
819 | ||
820 | /** | |
821 | * echo_char_raw - echo a character raw | |
822 | * @c: unicode byte to echo | |
823 | * @tty: terminal device | |
824 | * | |
825 | * Echo user input back onto the screen. This must be called only when | |
826 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
827 | * | |
828 | * This variant does not treat control characters specially. | |
829 | * | |
830 | * Locking: echo_lock to protect the echo buffer | |
831 | */ | |
832 | ||
57c94121 | 833 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 834 | { |
bddc7152 | 835 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 836 | if (c == ECHO_OP_START) { |
57c94121 JS |
837 | add_echo_byte(ECHO_OP_START, ldata); |
838 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 839 | } else { |
57c94121 | 840 | add_echo_byte(c, ldata); |
a88a69c9 | 841 | } |
bddc7152 | 842 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 | 843 | } |
1da177e4 | 844 | |
1da177e4 | 845 | /** |
a88a69c9 | 846 | * echo_char - echo a character |
1da177e4 LT |
847 | * @c: unicode byte to echo |
848 | * @tty: terminal device | |
849 | * | |
4edf1827 | 850 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 851 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 852 | * |
62b26358 JP |
853 | * This variant tags control characters to be echoed as "^X" |
854 | * (where X is the letter representing the control char). | |
a88a69c9 JP |
855 | * |
856 | * Locking: echo_lock to protect the echo buffer | |
1da177e4 LT |
857 | */ |
858 | ||
859 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
860 | { | |
bddc7152 JS |
861 | struct n_tty_data *ldata = tty->disc_data; |
862 | ||
863 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
864 | |
865 | if (c == ECHO_OP_START) { | |
57c94121 JS |
866 | add_echo_byte(ECHO_OP_START, ldata); |
867 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 868 | } else { |
62b26358 | 869 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
870 | add_echo_byte(ECHO_OP_START, ldata); |
871 | add_echo_byte(c, ldata); | |
a88a69c9 JP |
872 | } |
873 | ||
bddc7152 | 874 | mutex_unlock(&ldata->echo_lock); |
1da177e4 LT |
875 | } |
876 | ||
17b82060 | 877 | /** |
a88a69c9 | 878 | * finish_erasing - complete erase |
57c94121 | 879 | * @ldata: n_tty data |
17b82060 | 880 | */ |
a88a69c9 | 881 | |
57c94121 | 882 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 883 | { |
53c5ee2c | 884 | if (ldata->erasing) { |
57c94121 | 885 | echo_char_raw('/', ldata); |
53c5ee2c | 886 | ldata->erasing = 0; |
1da177e4 LT |
887 | } |
888 | } | |
889 | ||
890 | /** | |
891 | * eraser - handle erase function | |
892 | * @c: character input | |
893 | * @tty: terminal device | |
894 | * | |
3a4fa0a2 | 895 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
896 | * present in the stream from the driver layer. Handles the complexities |
897 | * of UTF-8 multibyte symbols. | |
17b82060 | 898 | * |
a88a69c9 | 899 | * Locking: read_lock for tty buffers |
1da177e4 | 900 | */ |
4edf1827 | 901 | |
1da177e4 LT |
902 | static void eraser(unsigned char c, struct tty_struct *tty) |
903 | { | |
53c5ee2c | 904 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
905 | enum { ERASE, WERASE, KILL } kill_type; |
906 | int head, seen_alnums, cnt; | |
907 | unsigned long flags; | |
908 | ||
17b82060 | 909 | /* FIXME: locking needed ? */ |
ba2e68ac | 910 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 911 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
912 | return; |
913 | } | |
914 | if (c == ERASE_CHAR(tty)) | |
915 | kill_type = ERASE; | |
916 | else if (c == WERASE_CHAR(tty)) | |
917 | kill_type = WERASE; | |
918 | else { | |
919 | if (!L_ECHO(tty)) { | |
98001214 | 920 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 921 | ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) & |
1da177e4 | 922 | (N_TTY_BUF_SIZE - 1)); |
ba2e68ac | 923 | ldata->read_head = ldata->canon_head; |
98001214 | 924 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
925 | return; |
926 | } | |
927 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
98001214 | 928 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 929 | ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) & |
1da177e4 | 930 | (N_TTY_BUF_SIZE - 1)); |
ba2e68ac | 931 | ldata->read_head = ldata->canon_head; |
98001214 | 932 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
57c94121 | 933 | finish_erasing(ldata); |
1da177e4 LT |
934 | echo_char(KILL_CHAR(tty), tty); |
935 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
936 | if (L_ECHOK(tty)) | |
57c94121 | 937 | echo_char_raw('\n', ldata); |
1da177e4 LT |
938 | return; |
939 | } | |
940 | kill_type = KILL; | |
941 | } | |
942 | ||
943 | seen_alnums = 0; | |
17b82060 | 944 | /* FIXME: Locking ?? */ |
ba2e68ac JS |
945 | while (ldata->read_head != ldata->canon_head) { |
946 | head = ldata->read_head; | |
1da177e4 LT |
947 | |
948 | /* erase a single possibly multibyte character */ | |
949 | do { | |
950 | head = (head - 1) & (N_TTY_BUF_SIZE-1); | |
ba2e68ac JS |
951 | c = ldata->read_buf[head]; |
952 | } while (is_continuation(c, tty) && head != ldata->canon_head); | |
1da177e4 LT |
953 | |
954 | /* do not partially erase */ | |
955 | if (is_continuation(c, tty)) | |
956 | break; | |
957 | ||
958 | if (kill_type == WERASE) { | |
959 | /* Equivalent to BSD's ALTWERASE. */ | |
960 | if (isalnum(c) || c == '_') | |
961 | seen_alnums++; | |
962 | else if (seen_alnums) | |
963 | break; | |
964 | } | |
ba2e68ac | 965 | cnt = (ldata->read_head - head) & (N_TTY_BUF_SIZE-1); |
98001214 | 966 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac JS |
967 | ldata->read_head = head; |
968 | ldata->read_cnt -= cnt; | |
98001214 | 969 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
970 | if (L_ECHO(tty)) { |
971 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 972 | if (!ldata->erasing) { |
57c94121 | 973 | echo_char_raw('\\', ldata); |
53c5ee2c | 974 | ldata->erasing = 1; |
1da177e4 LT |
975 | } |
976 | /* if cnt > 1, output a multi-byte character */ | |
977 | echo_char(c, tty); | |
978 | while (--cnt > 0) { | |
979 | head = (head+1) & (N_TTY_BUF_SIZE-1); | |
57c94121 JS |
980 | echo_char_raw(ldata->read_buf[head], |
981 | ldata); | |
982 | echo_move_back_col(ldata); | |
1da177e4 LT |
983 | } |
984 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
985 | echo_char(ERASE_CHAR(tty), tty); | |
986 | } else if (c == '\t') { | |
a88a69c9 JP |
987 | unsigned int num_chars = 0; |
988 | int after_tab = 0; | |
ba2e68ac | 989 | unsigned long tail = ldata->read_head; |
a88a69c9 JP |
990 | |
991 | /* | |
992 | * Count the columns used for characters | |
993 | * since the start of input or after a | |
994 | * previous tab. | |
995 | * This info is used to go back the correct | |
996 | * number of columns. | |
997 | */ | |
ba2e68ac | 998 | while (tail != ldata->canon_head) { |
a88a69c9 | 999 | tail = (tail-1) & (N_TTY_BUF_SIZE-1); |
ba2e68ac | 1000 | c = ldata->read_buf[tail]; |
a88a69c9 JP |
1001 | if (c == '\t') { |
1002 | after_tab = 1; | |
1003 | break; | |
300a6204 | 1004 | } else if (iscntrl(c)) { |
1da177e4 | 1005 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1006 | num_chars += 2; |
1007 | } else if (!is_continuation(c, tty)) { | |
1008 | num_chars++; | |
1009 | } | |
1da177e4 | 1010 | } |
57c94121 | 1011 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1012 | } else { |
1013 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1014 | echo_char_raw('\b', ldata); |
1015 | echo_char_raw(' ', ldata); | |
1016 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1017 | } |
1018 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1019 | echo_char_raw('\b', ldata); |
1020 | echo_char_raw(' ', ldata); | |
1021 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1022 | } |
1023 | } | |
1024 | } | |
1025 | if (kill_type == ERASE) | |
1026 | break; | |
1027 | } | |
ba2e68ac | 1028 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1029 | finish_erasing(ldata); |
1da177e4 LT |
1030 | } |
1031 | ||
1032 | /** | |
1033 | * isig - handle the ISIG optio | |
1034 | * @sig: signal | |
1035 | * @tty: terminal | |
1da177e4 | 1036 | * |
8c985d18 PH |
1037 | * Called when a signal is being sent due to terminal input. |
1038 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1039 | * |
8c985d18 | 1040 | * Locking: ctrl_lock |
1da177e4 | 1041 | */ |
4edf1827 | 1042 | |
8c985d18 | 1043 | static inline void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1044 | { |
8c985d18 PH |
1045 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1046 | if (tty_pgrp) { | |
1047 | kill_pgrp(tty_pgrp, sig, 1); | |
1048 | put_pid(tty_pgrp); | |
1da177e4 LT |
1049 | } |
1050 | } | |
1051 | ||
1052 | /** | |
1053 | * n_tty_receive_break - handle break | |
1054 | * @tty: terminal | |
1055 | * | |
1056 | * An RS232 break event has been hit in the incoming bitstream. This | |
1057 | * can cause a variety of events depending upon the termios settings. | |
1058 | * | |
1059 | * Called from the receive_buf path so single threaded. | |
1060 | */ | |
4edf1827 | 1061 | |
1da177e4 LT |
1062 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1063 | { | |
57c94121 JS |
1064 | struct n_tty_data *ldata = tty->disc_data; |
1065 | ||
1da177e4 LT |
1066 | if (I_IGNBRK(tty)) |
1067 | return; | |
1068 | if (I_BRKINT(tty)) { | |
8c985d18 PH |
1069 | isig(SIGINT, tty); |
1070 | if (!L_NOFLSH(tty)) { | |
1071 | n_tty_flush_buffer(tty); | |
1072 | tty_driver_flush_buffer(tty); | |
1073 | } | |
1da177e4 LT |
1074 | return; |
1075 | } | |
1076 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1077 | put_tty_queue('\377', ldata); |
1078 | put_tty_queue('\0', ldata); | |
1da177e4 | 1079 | } |
57c94121 | 1080 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1081 | wake_up_interruptible(&tty->read_wait); |
1082 | } | |
1083 | ||
1084 | /** | |
1085 | * n_tty_receive_overrun - handle overrun reporting | |
1086 | * @tty: terminal | |
1087 | * | |
1088 | * Data arrived faster than we could process it. While the tty | |
1089 | * driver has flagged this the bits that were missed are gone | |
1090 | * forever. | |
1091 | * | |
1092 | * Called from the receive_buf path so single threaded. Does not | |
1093 | * need locking as num_overrun and overrun_time are function | |
1094 | * private. | |
1095 | */ | |
4edf1827 | 1096 | |
1da177e4 LT |
1097 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1098 | { | |
53c5ee2c | 1099 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1100 | char buf[64]; |
1101 | ||
53c5ee2c JS |
1102 | ldata->num_overrun++; |
1103 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1104 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1105 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1106 | tty_name(tty, buf), | |
53c5ee2c JS |
1107 | ldata->num_overrun); |
1108 | ldata->overrun_time = jiffies; | |
1109 | ldata->num_overrun = 0; | |
1da177e4 LT |
1110 | } |
1111 | } | |
1112 | ||
1113 | /** | |
1114 | * n_tty_receive_parity_error - error notifier | |
1115 | * @tty: terminal device | |
1116 | * @c: character | |
1117 | * | |
1118 | * Process a parity error and queue the right data to indicate | |
3a4fa0a2 | 1119 | * the error case if necessary. Locking as per n_tty_receive_buf. |
1da177e4 LT |
1120 | */ |
1121 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1122 | unsigned char c) | |
1123 | { | |
57c94121 JS |
1124 | struct n_tty_data *ldata = tty->disc_data; |
1125 | ||
4edf1827 | 1126 | if (I_IGNPAR(tty)) |
1da177e4 | 1127 | return; |
1da177e4 | 1128 | if (I_PARMRK(tty)) { |
57c94121 JS |
1129 | put_tty_queue('\377', ldata); |
1130 | put_tty_queue('\0', ldata); | |
1131 | put_tty_queue(c, ldata); | |
1da177e4 | 1132 | } else if (I_INPCK(tty)) |
57c94121 | 1133 | put_tty_queue('\0', ldata); |
1da177e4 | 1134 | else |
57c94121 | 1135 | put_tty_queue(c, ldata); |
1da177e4 LT |
1136 | wake_up_interruptible(&tty->read_wait); |
1137 | } | |
1138 | ||
1139 | /** | |
1140 | * n_tty_receive_char - perform processing | |
1141 | * @tty: terminal device | |
1142 | * @c: character | |
1143 | * | |
1144 | * Process an individual character of input received from the driver. | |
4edf1827 | 1145 | * This is serialized with respect to itself by the rules for the |
1da177e4 LT |
1146 | * driver above. |
1147 | */ | |
1148 | ||
1149 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1150 | { | |
53c5ee2c | 1151 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1152 | unsigned long flags; |
acc71bba | 1153 | int parmrk; |
1da177e4 | 1154 | |
53c5ee2c | 1155 | if (ldata->raw) { |
57c94121 | 1156 | put_tty_queue(c, ldata); |
1da177e4 LT |
1157 | return; |
1158 | } | |
4edf1827 | 1159 | |
1da177e4 LT |
1160 | if (I_ISTRIP(tty)) |
1161 | c &= 0x7f; | |
1162 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1163 | c = tolower(c); |
1da177e4 | 1164 | |
26df6d13 | 1165 | if (L_EXTPROC(tty)) { |
57c94121 | 1166 | put_tty_queue(c, ldata); |
26df6d13 | 1167 | return; |
1168 | } | |
1169 | ||
54d2a37e | 1170 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1171 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1172 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1173 | start_tty(tty); |
a88a69c9 JP |
1174 | process_echoes(tty); |
1175 | } | |
54d2a37e | 1176 | |
1da177e4 LT |
1177 | if (tty->closing) { |
1178 | if (I_IXON(tty)) { | |
a88a69c9 | 1179 | if (c == START_CHAR(tty)) { |
1da177e4 | 1180 | start_tty(tty); |
a88a69c9 | 1181 | process_echoes(tty); |
300a6204 | 1182 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1183 | stop_tty(tty); |
1184 | } | |
1185 | return; | |
1186 | } | |
1187 | ||
1188 | /* | |
1189 | * If the previous character was LNEXT, or we know that this | |
1190 | * character is not one of the characters that we'll have to | |
1191 | * handle specially, do shortcut processing to speed things | |
1192 | * up. | |
1193 | */ | |
3fe780b3 | 1194 | if (!test_bit(c, ldata->process_char_map) || ldata->lnext) { |
53c5ee2c | 1195 | ldata->lnext = 0; |
acc71bba | 1196 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ba2e68ac | 1197 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1198 | /* beep if no space */ |
7e94b1d9 JP |
1199 | if (L_ECHO(tty)) |
1200 | process_output('\a', tty); | |
acc71bba JP |
1201 | return; |
1202 | } | |
1203 | if (L_ECHO(tty)) { | |
57c94121 | 1204 | finish_erasing(ldata); |
1da177e4 | 1205 | /* Record the column of first canon char. */ |
ba2e68ac | 1206 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1207 | echo_set_canon_col(ldata); |
1da177e4 | 1208 | echo_char(c, tty); |
a88a69c9 | 1209 | process_echoes(tty); |
1da177e4 | 1210 | } |
acc71bba | 1211 | if (parmrk) |
57c94121 JS |
1212 | put_tty_queue(c, ldata); |
1213 | put_tty_queue(c, ldata); | |
1da177e4 LT |
1214 | return; |
1215 | } | |
4edf1827 | 1216 | |
1da177e4 LT |
1217 | if (I_IXON(tty)) { |
1218 | if (c == START_CHAR(tty)) { | |
1219 | start_tty(tty); | |
a88a69c9 | 1220 | process_echoes(tty); |
1da177e4 LT |
1221 | return; |
1222 | } | |
1223 | if (c == STOP_CHAR(tty)) { | |
1224 | stop_tty(tty); | |
1225 | return; | |
1226 | } | |
1227 | } | |
575537b3 | 1228 | |
1da177e4 LT |
1229 | if (L_ISIG(tty)) { |
1230 | int signal; | |
1231 | signal = SIGINT; | |
1232 | if (c == INTR_CHAR(tty)) | |
1233 | goto send_signal; | |
1234 | signal = SIGQUIT; | |
1235 | if (c == QUIT_CHAR(tty)) | |
1236 | goto send_signal; | |
1237 | signal = SIGTSTP; | |
1238 | if (c == SUSP_CHAR(tty)) { | |
1239 | send_signal: | |
ec5b1157 JP |
1240 | if (!L_NOFLSH(tty)) { |
1241 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1242 | tty_driver_flush_buffer(tty); |
ec5b1157 | 1243 | } |
a88a69c9 JP |
1244 | if (I_IXON(tty)) |
1245 | start_tty(tty); | |
1246 | if (L_ECHO(tty)) { | |
ec5b1157 | 1247 | echo_char(c, tty); |
a88a69c9 JP |
1248 | process_echoes(tty); |
1249 | } | |
8c985d18 | 1250 | isig(signal, tty); |
1da177e4 LT |
1251 | return; |
1252 | } | |
1253 | } | |
575537b3 JP |
1254 | |
1255 | if (c == '\r') { | |
1256 | if (I_IGNCR(tty)) | |
1257 | return; | |
1258 | if (I_ICRNL(tty)) | |
1259 | c = '\n'; | |
1260 | } else if (c == '\n' && I_INLCR(tty)) | |
1261 | c = '\r'; | |
1262 | ||
53c5ee2c | 1263 | if (ldata->icanon) { |
1da177e4 LT |
1264 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1265 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1266 | eraser(c, tty); | |
a88a69c9 | 1267 | process_echoes(tty); |
1da177e4 LT |
1268 | return; |
1269 | } | |
1270 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1271 | ldata->lnext = 1; |
1da177e4 | 1272 | if (L_ECHO(tty)) { |
57c94121 | 1273 | finish_erasing(ldata); |
1da177e4 | 1274 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1275 | echo_char_raw('^', ldata); |
1276 | echo_char_raw('\b', ldata); | |
a88a69c9 | 1277 | process_echoes(tty); |
1da177e4 LT |
1278 | } |
1279 | } | |
1280 | return; | |
1281 | } | |
1282 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1283 | L_IEXTEN(tty)) { | |
ba2e68ac | 1284 | unsigned long tail = ldata->canon_head; |
1da177e4 | 1285 | |
57c94121 | 1286 | finish_erasing(ldata); |
1da177e4 | 1287 | echo_char(c, tty); |
57c94121 | 1288 | echo_char_raw('\n', ldata); |
ba2e68ac JS |
1289 | while (tail != ldata->read_head) { |
1290 | echo_char(ldata->read_buf[tail], tty); | |
1da177e4 LT |
1291 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); |
1292 | } | |
a88a69c9 | 1293 | process_echoes(tty); |
1da177e4 LT |
1294 | return; |
1295 | } | |
1296 | if (c == '\n') { | |
ba2e68ac | 1297 | if (ldata->read_cnt >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1298 | if (L_ECHO(tty)) |
1299 | process_output('\a', tty); | |
acc71bba JP |
1300 | return; |
1301 | } | |
1302 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
57c94121 | 1303 | echo_char_raw('\n', ldata); |
a88a69c9 | 1304 | process_echoes(tty); |
1da177e4 LT |
1305 | } |
1306 | goto handle_newline; | |
1307 | } | |
1308 | if (c == EOF_CHAR(tty)) { | |
ba2e68ac | 1309 | if (ldata->read_cnt >= N_TTY_BUF_SIZE) |
acc71bba | 1310 | return; |
ba2e68ac | 1311 | if (ldata->canon_head != ldata->read_head) |
4edf1827 | 1312 | set_bit(TTY_PUSH, &tty->flags); |
1da177e4 LT |
1313 | c = __DISABLED_CHAR; |
1314 | goto handle_newline; | |
1315 | } | |
1316 | if ((c == EOL_CHAR(tty)) || | |
1317 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1318 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1319 | ? 1 : 0; | |
ba2e68ac | 1320 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) { |
7e94b1d9 JP |
1321 | if (L_ECHO(tty)) |
1322 | process_output('\a', tty); | |
acc71bba JP |
1323 | return; |
1324 | } | |
1da177e4 LT |
1325 | /* |
1326 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1327 | */ | |
1328 | if (L_ECHO(tty)) { | |
1da177e4 | 1329 | /* Record the column of first canon char. */ |
ba2e68ac | 1330 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1331 | echo_set_canon_col(ldata); |
1da177e4 | 1332 | echo_char(c, tty); |
a88a69c9 | 1333 | process_echoes(tty); |
1da177e4 LT |
1334 | } |
1335 | /* | |
1336 | * XXX does PARMRK doubling happen for | |
1337 | * EOL_CHAR and EOL2_CHAR? | |
1338 | */ | |
acc71bba | 1339 | if (parmrk) |
57c94121 | 1340 | put_tty_queue(c, ldata); |
1da177e4 | 1341 | |
4edf1827 | 1342 | handle_newline: |
98001214 | 1343 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 1344 | set_bit(ldata->read_head, ldata->read_flags); |
57c94121 | 1345 | put_tty_queue_nolock(c, ldata); |
ba2e68ac JS |
1346 | ldata->canon_head = ldata->read_head; |
1347 | ldata->canon_data++; | |
98001214 | 1348 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1349 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1350 | if (waitqueue_active(&tty->read_wait)) | |
1351 | wake_up_interruptible(&tty->read_wait); | |
1352 | return; | |
1353 | } | |
1354 | } | |
4edf1827 | 1355 | |
acc71bba | 1356 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ba2e68ac | 1357 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1358 | /* beep if no space */ |
7e94b1d9 JP |
1359 | if (L_ECHO(tty)) |
1360 | process_output('\a', tty); | |
acc71bba JP |
1361 | return; |
1362 | } | |
1363 | if (L_ECHO(tty)) { | |
57c94121 | 1364 | finish_erasing(ldata); |
1da177e4 | 1365 | if (c == '\n') |
57c94121 | 1366 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1367 | else { |
1368 | /* Record the column of first canon char. */ | |
ba2e68ac | 1369 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1370 | echo_set_canon_col(ldata); |
1da177e4 LT |
1371 | echo_char(c, tty); |
1372 | } | |
a88a69c9 | 1373 | process_echoes(tty); |
1da177e4 LT |
1374 | } |
1375 | ||
acc71bba | 1376 | if (parmrk) |
57c94121 | 1377 | put_tty_queue(c, ldata); |
1da177e4 | 1378 | |
57c94121 | 1379 | put_tty_queue(c, ldata); |
4edf1827 | 1380 | } |
1da177e4 | 1381 | |
1da177e4 LT |
1382 | |
1383 | /** | |
1384 | * n_tty_write_wakeup - asynchronous I/O notifier | |
1385 | * @tty: tty device | |
1386 | * | |
1387 | * Required for the ptys, serial driver etc. since processes | |
1388 | * that attach themselves to the master and rely on ASYNC | |
1389 | * IO must be woken up | |
1390 | */ | |
1391 | ||
1392 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
1393 | { | |
ff8cb0fd | 1394 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) |
1da177e4 | 1395 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); |
1da177e4 LT |
1396 | } |
1397 | ||
1398 | /** | |
1399 | * n_tty_receive_buf - data receive | |
1400 | * @tty: terminal device | |
1401 | * @cp: buffer | |
1402 | * @fp: flag buffer | |
1403 | * @count: characters | |
1404 | * | |
1405 | * Called by the terminal driver when a block of characters has | |
1406 | * been received. This function must be called from soft contexts | |
1407 | * not from interrupt context. The driver is responsible for making | |
1408 | * calls one at a time and in order (or using flush_to_ldisc) | |
1409 | */ | |
4edf1827 | 1410 | |
55db4c64 LT |
1411 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1412 | char *fp, int count) | |
1da177e4 | 1413 | { |
53c5ee2c | 1414 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1415 | const unsigned char *p; |
1416 | char *f, flags = TTY_NORMAL; | |
1417 | int i; | |
1418 | char buf[64]; | |
1419 | unsigned long cpuflags; | |
1420 | ||
53c5ee2c | 1421 | if (ldata->real_raw) { |
98001214 | 1422 | raw_spin_lock_irqsave(&ldata->read_lock, cpuflags); |
ba2e68ac JS |
1423 | i = min(N_TTY_BUF_SIZE - ldata->read_cnt, |
1424 | N_TTY_BUF_SIZE - ldata->read_head); | |
1da177e4 | 1425 | i = min(count, i); |
ba2e68ac JS |
1426 | memcpy(ldata->read_buf + ldata->read_head, cp, i); |
1427 | ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1428 | ldata->read_cnt += i; | |
1da177e4 LT |
1429 | cp += i; |
1430 | count -= i; | |
1431 | ||
ba2e68ac JS |
1432 | i = min(N_TTY_BUF_SIZE - ldata->read_cnt, |
1433 | N_TTY_BUF_SIZE - ldata->read_head); | |
1da177e4 | 1434 | i = min(count, i); |
ba2e68ac JS |
1435 | memcpy(ldata->read_buf + ldata->read_head, cp, i); |
1436 | ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1437 | ldata->read_cnt += i; | |
98001214 | 1438 | raw_spin_unlock_irqrestore(&ldata->read_lock, cpuflags); |
1da177e4 | 1439 | } else { |
4edf1827 | 1440 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1441 | if (f) |
1442 | flags = *f++; | |
1443 | switch (flags) { | |
1444 | case TTY_NORMAL: | |
1445 | n_tty_receive_char(tty, *p); | |
1446 | break; | |
1447 | case TTY_BREAK: | |
1448 | n_tty_receive_break(tty); | |
1449 | break; | |
1450 | case TTY_PARITY: | |
1451 | case TTY_FRAME: | |
1452 | n_tty_receive_parity_error(tty, *p); | |
1453 | break; | |
1454 | case TTY_OVERRUN: | |
1455 | n_tty_receive_overrun(tty); | |
1456 | break; | |
1457 | default: | |
4edf1827 | 1458 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1459 | tty_name(tty, buf), flags); |
1460 | break; | |
1461 | } | |
1462 | } | |
f34d7a5b AC |
1463 | if (tty->ops->flush_chars) |
1464 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1465 | } |
1466 | ||
7879a9f9 | 1467 | set_room(tty); |
55db4c64 | 1468 | |
f6c8dbe6 | 1469 | if ((!ldata->icanon && (ldata->read_cnt >= ldata->minimum_to_wake)) || |
26df6d13 | 1470 | L_EXTPROC(tty)) { |
1da177e4 LT |
1471 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1472 | if (waitqueue_active(&tty->read_wait)) | |
1473 | wake_up_interruptible(&tty->read_wait); | |
1474 | } | |
1475 | ||
1476 | /* | |
1477 | * Check the remaining room for the input canonicalization | |
1478 | * mode. We don't want to throttle the driver if we're in | |
1479 | * canonical mode and don't have a newline yet! | |
1480 | */ | |
e91e52e4 PH |
1481 | while (1) { |
1482 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
1483 | if (tty->receive_room >= TTY_THRESHOLD_THROTTLE) | |
1484 | break; | |
1485 | if (!tty_throttle_safe(tty)) | |
1486 | break; | |
1487 | } | |
1488 | __tty_set_flow_change(tty, 0); | |
1da177e4 LT |
1489 | } |
1490 | ||
1491 | int is_ignored(int sig) | |
1492 | { | |
1493 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1494 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1495 | } |
1496 | ||
1497 | /** | |
1498 | * n_tty_set_termios - termios data changed | |
1499 | * @tty: terminal | |
1500 | * @old: previous data | |
1501 | * | |
1502 | * Called by the tty layer when the user changes termios flags so | |
1503 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1504 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1505 | * guaranteed that this function will not be re-entered or in progress |
1506 | * when the ldisc is closed. | |
17b82060 AC |
1507 | * |
1508 | * Locking: Caller holds tty->termios_mutex | |
1da177e4 | 1509 | */ |
4edf1827 AC |
1510 | |
1511 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1512 | { |
53c5ee2c | 1513 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1514 | int canon_change = 1; |
47afa7a5 AC |
1515 | |
1516 | if (old) | |
adc8d746 | 1517 | canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON; |
47afa7a5 | 1518 | if (canon_change) { |
3fe780b3 | 1519 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
ba2e68ac JS |
1520 | ldata->canon_head = ldata->read_tail; |
1521 | ldata->canon_data = 0; | |
53c5ee2c | 1522 | ldata->erasing = 0; |
47afa7a5 AC |
1523 | } |
1524 | ||
ba2e68ac | 1525 | if (canon_change && !L_ICANON(tty) && ldata->read_cnt) |
47afa7a5 | 1526 | wake_up_interruptible(&tty->read_wait); |
4edf1827 | 1527 | |
53c5ee2c | 1528 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1529 | |
1da177e4 LT |
1530 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1531 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1532 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1533 | I_PARMRK(tty)) { | |
3fe780b3 | 1534 | bitmap_zero(ldata->process_char_map, 256); |
1da177e4 LT |
1535 | |
1536 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
3fe780b3 | 1537 | set_bit('\r', ldata->process_char_map); |
1da177e4 | 1538 | if (I_INLCR(tty)) |
3fe780b3 | 1539 | set_bit('\n', ldata->process_char_map); |
1da177e4 LT |
1540 | |
1541 | if (L_ICANON(tty)) { | |
3fe780b3 JS |
1542 | set_bit(ERASE_CHAR(tty), ldata->process_char_map); |
1543 | set_bit(KILL_CHAR(tty), ldata->process_char_map); | |
1544 | set_bit(EOF_CHAR(tty), ldata->process_char_map); | |
1545 | set_bit('\n', ldata->process_char_map); | |
1546 | set_bit(EOL_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1547 | if (L_IEXTEN(tty)) { |
1548 | set_bit(WERASE_CHAR(tty), | |
3fe780b3 | 1549 | ldata->process_char_map); |
1da177e4 | 1550 | set_bit(LNEXT_CHAR(tty), |
3fe780b3 | 1551 | ldata->process_char_map); |
1da177e4 | 1552 | set_bit(EOL2_CHAR(tty), |
3fe780b3 | 1553 | ldata->process_char_map); |
1da177e4 LT |
1554 | if (L_ECHO(tty)) |
1555 | set_bit(REPRINT_CHAR(tty), | |
3fe780b3 | 1556 | ldata->process_char_map); |
1da177e4 LT |
1557 | } |
1558 | } | |
1559 | if (I_IXON(tty)) { | |
3fe780b3 JS |
1560 | set_bit(START_CHAR(tty), ldata->process_char_map); |
1561 | set_bit(STOP_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1562 | } |
1563 | if (L_ISIG(tty)) { | |
3fe780b3 JS |
1564 | set_bit(INTR_CHAR(tty), ldata->process_char_map); |
1565 | set_bit(QUIT_CHAR(tty), ldata->process_char_map); | |
1566 | set_bit(SUSP_CHAR(tty), ldata->process_char_map); | |
1da177e4 | 1567 | } |
3fe780b3 | 1568 | clear_bit(__DISABLED_CHAR, ldata->process_char_map); |
53c5ee2c JS |
1569 | ldata->raw = 0; |
1570 | ldata->real_raw = 0; | |
1da177e4 | 1571 | } else { |
53c5ee2c | 1572 | ldata->raw = 1; |
1da177e4 LT |
1573 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1574 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1575 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1576 | ldata->real_raw = 1; |
1da177e4 | 1577 | else |
53c5ee2c | 1578 | ldata->real_raw = 0; |
1da177e4 | 1579 | } |
55db4c64 | 1580 | n_tty_set_room(tty); |
dab73b4e WY |
1581 | /* |
1582 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1583 | * been stopped by STOP_CHAR(tty) before it. | |
1584 | */ | |
1585 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { | |
1586 | start_tty(tty); | |
1587 | } | |
1588 | ||
f34d7a5b AC |
1589 | /* The termios change make the tty ready for I/O */ |
1590 | wake_up_interruptible(&tty->write_wait); | |
1591 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1592 | } |
1593 | ||
1594 | /** | |
1595 | * n_tty_close - close the ldisc for this tty | |
1596 | * @tty: device | |
1597 | * | |
4edf1827 AC |
1598 | * Called from the terminal layer when this line discipline is |
1599 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1600 | * discipline change. The function will not be called while other |
1601 | * ldisc methods are in progress. | |
1602 | */ | |
4edf1827 | 1603 | |
1da177e4 LT |
1604 | static void n_tty_close(struct tty_struct *tty) |
1605 | { | |
70ece7a7 JS |
1606 | struct n_tty_data *ldata = tty->disc_data; |
1607 | ||
79901317 PH |
1608 | if (tty->link) |
1609 | n_tty_packet_mode_flush(tty); | |
1610 | ||
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; |
b66f4fa5 | 1648 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1649 | ldata->column = 0; |
f6c8dbe6 | 1650 | ldata->minimum_to_wake = 1; |
1da177e4 | 1651 | tty->closing = 0; |
b66f4fa5 PH |
1652 | /* indicate buffer work may resume */ |
1653 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1654 | n_tty_set_termios(tty, NULL); | |
1655 | tty_unthrottle(tty); | |
70ece7a7 | 1656 | |
1da177e4 | 1657 | return 0; |
b91939f5 | 1658 | err_free_bufs: |
ba2e68ac JS |
1659 | kfree(ldata->read_buf); |
1660 | kfree(ldata->echo_buf); | |
70ece7a7 JS |
1661 | kfree(ldata); |
1662 | err: | |
b91939f5 | 1663 | return -ENOMEM; |
1da177e4 LT |
1664 | } |
1665 | ||
1666 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1667 | { | |
53c5ee2c JS |
1668 | struct n_tty_data *ldata = tty->disc_data; |
1669 | ||
e043e42b | 1670 | tty_flush_to_ldisc(tty); |
53c5ee2c | 1671 | if (ldata->icanon && !L_EXTPROC(tty)) { |
ba2e68ac | 1672 | if (ldata->canon_data) |
1da177e4 | 1673 | return 1; |
ba2e68ac | 1674 | } else if (ldata->read_cnt >= (amt ? amt : 1)) |
1da177e4 LT |
1675 | return 1; |
1676 | ||
1677 | return 0; | |
1678 | } | |
1679 | ||
1680 | /** | |
bbd20759 | 1681 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1682 | * @tty: terminal device |
1683 | * @b: user data | |
1684 | * @nr: size of data | |
1685 | * | |
11a96d18 | 1686 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1687 | * ICANON is off; it copies characters straight from the tty queue to |
1688 | * user space directly. It can be profitably called twice; once to | |
1689 | * drain the space from the tail pointer to the (physical) end of the | |
1690 | * buffer, and once to drain the space from the (physical) beginning of | |
1691 | * the buffer to head pointer. | |
1692 | * | |
bddc7152 | 1693 | * Called under the ldata->atomic_read_lock sem |
1da177e4 LT |
1694 | * |
1695 | */ | |
4edf1827 | 1696 | |
33f0f88f | 1697 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1698 | unsigned char __user **b, |
1699 | size_t *nr) | |
1700 | ||
1701 | { | |
53c5ee2c | 1702 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1703 | int retval; |
1704 | size_t n; | |
1705 | unsigned long flags; | |
3fa10cc8 | 1706 | bool is_eof; |
1da177e4 LT |
1707 | |
1708 | retval = 0; | |
98001214 | 1709 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 1710 | n = min(ldata->read_cnt, N_TTY_BUF_SIZE - ldata->read_tail); |
1da177e4 | 1711 | n = min(*nr, n); |
98001214 | 1712 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 | 1713 | if (n) { |
ba2e68ac | 1714 | retval = copy_to_user(*b, &ldata->read_buf[ldata->read_tail], n); |
1da177e4 | 1715 | n -= retval; |
3fa10cc8 | 1716 | is_eof = n == 1 && |
ba2e68ac JS |
1717 | ldata->read_buf[ldata->read_tail] == EOF_CHAR(tty); |
1718 | tty_audit_add_data(tty, &ldata->read_buf[ldata->read_tail], n, | |
53c5ee2c | 1719 | ldata->icanon); |
98001214 | 1720 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac JS |
1721 | ldata->read_tail = (ldata->read_tail + n) & (N_TTY_BUF_SIZE-1); |
1722 | ldata->read_cnt -= n; | |
26df6d13 | 1723 | /* Turn single EOF into zero-length read */ |
ba2e68ac | 1724 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !ldata->read_cnt) |
3fa10cc8 | 1725 | n = 0; |
98001214 | 1726 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1727 | *b += n; |
1728 | *nr -= n; | |
1729 | } | |
1730 | return retval; | |
1731 | } | |
1732 | ||
cc4191dc | 1733 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1734 | size_t, loff_t *); |
1da177e4 LT |
1735 | |
1736 | /** | |
1737 | * job_control - check job control | |
1738 | * @tty: tty | |
1739 | * @file: file handle | |
1740 | * | |
1741 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1742 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1743 | * error code if action should be taken. |
04f378b1 | 1744 | * |
01a5e440 PH |
1745 | * Locking: redirected write test is safe |
1746 | * current->signal->tty check is safe | |
1747 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 1748 | */ |
4edf1827 | 1749 | |
1da177e4 LT |
1750 | static int job_control(struct tty_struct *tty, struct file *file) |
1751 | { | |
1752 | /* Job control check -- must be done at start and after | |
1753 | every sleep (POSIX.1 7.1.1.4). */ | |
1754 | /* NOTE: not yet done after every sleep pending a thorough | |
1755 | check of the logic of this change. -- jlc */ | |
1756 | /* don't stop on /dev/console */ | |
01a5e440 PH |
1757 | if (file->f_op->write == redirected_tty_write || |
1758 | current->signal->tty != tty) | |
1759 | return 0; | |
1760 | ||
1761 | spin_lock_irq(&tty->ctrl_lock); | |
1762 | if (!tty->pgrp) | |
1763 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
1764 | else if (task_pgrp(current) != tty->pgrp) { | |
1765 | spin_unlock_irq(&tty->ctrl_lock); | |
1766 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
1767 | return -EIO; | |
1768 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
1769 | set_thread_flag(TIF_SIGPENDING); | |
1770 | return -ERESTARTSYS; | |
1da177e4 | 1771 | } |
01a5e440 | 1772 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
1773 | return 0; |
1774 | } | |
4edf1827 | 1775 | |
1da177e4 LT |
1776 | |
1777 | /** | |
11a96d18 | 1778 | * n_tty_read - read function for tty |
1da177e4 LT |
1779 | * @tty: tty device |
1780 | * @file: file object | |
1781 | * @buf: userspace buffer pointer | |
1782 | * @nr: size of I/O | |
1783 | * | |
1784 | * Perform reads for the line discipline. We are guaranteed that the | |
1785 | * line discipline will not be closed under us but we may get multiple | |
1786 | * parallel readers and must handle this ourselves. We may also get | |
1787 | * a hangup. Always called in user context, may sleep. | |
1788 | * | |
1789 | * This code must be sure never to sleep through a hangup. | |
1790 | */ | |
4edf1827 | 1791 | |
11a96d18 | 1792 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1793 | unsigned char __user *buf, size_t nr) |
1794 | { | |
53c5ee2c | 1795 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1796 | unsigned char __user *b = buf; |
1797 | DECLARE_WAITQUEUE(wait, current); | |
1798 | int c; | |
1799 | int minimum, time; | |
1800 | ssize_t retval = 0; | |
1801 | ssize_t size; | |
1802 | long timeout; | |
1803 | unsigned long flags; | |
04f378b1 | 1804 | int packet; |
1da177e4 LT |
1805 | |
1806 | do_it_again: | |
1da177e4 | 1807 | c = job_control(tty, file); |
4edf1827 | 1808 | if (c < 0) |
1da177e4 | 1809 | return c; |
4edf1827 | 1810 | |
1da177e4 LT |
1811 | minimum = time = 0; |
1812 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 1813 | if (!ldata->icanon) { |
1da177e4 LT |
1814 | minimum = MIN_CHAR(tty); |
1815 | if (minimum) { | |
a6e54319 | 1816 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 1817 | if (time) |
f6c8dbe6 | 1818 | ldata->minimum_to_wake = 1; |
1da177e4 | 1819 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
1820 | (ldata->minimum_to_wake > minimum)) |
1821 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 1822 | } else { |
a6e54319 | 1823 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 1824 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
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 | |
f6c8dbe6 | 1864 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 1865 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 1866 | ldata->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 | 1885 | n_tty_set_room(tty); |
1da177e4 | 1886 | timeout = schedule_timeout(timeout); |
1da177e4 LT |
1887 | continue; |
1888 | } | |
1889 | __set_current_state(TASK_RUNNING); | |
1890 | ||
1891 | /* Deal with packet mode. */ | |
04f378b1 | 1892 | if (packet && b == buf) { |
522ed776 | 1893 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
1894 | retval = -EFAULT; |
1895 | b--; | |
1896 | break; | |
1897 | } | |
1898 | nr--; | |
1899 | } | |
1900 | ||
53c5ee2c | 1901 | if (ldata->icanon && !L_EXTPROC(tty)) { |
1da177e4 | 1902 | /* N.B. avoid overrun if nr == 0 */ |
98001214 | 1903 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 1904 | while (nr && ldata->read_cnt) { |
4edf1827 | 1905 | int eol; |
1da177e4 | 1906 | |
ba2e68ac | 1907 | eol = test_and_clear_bit(ldata->read_tail, |
3fe780b3 | 1908 | ldata->read_flags); |
ba2e68ac JS |
1909 | c = ldata->read_buf[ldata->read_tail]; |
1910 | ldata->read_tail = ((ldata->read_tail+1) & | |
1da177e4 | 1911 | (N_TTY_BUF_SIZE-1)); |
ba2e68ac | 1912 | ldata->read_cnt--; |
1da177e4 LT |
1913 | if (eol) { |
1914 | /* this test should be redundant: | |
1915 | * we shouldn't be reading data if | |
1916 | * canon_data is 0 | |
1917 | */ | |
ba2e68ac JS |
1918 | if (--ldata->canon_data < 0) |
1919 | ldata->canon_data = 0; | |
1da177e4 | 1920 | } |
98001214 | 1921 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1922 | |
1923 | if (!eol || (c != __DISABLED_CHAR)) { | |
522ed776 | 1924 | if (tty_put_user(tty, c, b++)) { |
1da177e4 LT |
1925 | retval = -EFAULT; |
1926 | b--; | |
98001214 | 1927 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
1da177e4 LT |
1928 | break; |
1929 | } | |
1930 | nr--; | |
1931 | } | |
522ed776 MT |
1932 | if (eol) { |
1933 | tty_audit_push(tty); | |
98001214 | 1934 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
1da177e4 | 1935 | break; |
522ed776 | 1936 | } |
98001214 | 1937 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
1da177e4 | 1938 | } |
98001214 | 1939 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1940 | if (retval) |
1941 | break; | |
1942 | } else { | |
1943 | int uncopied; | |
04f378b1 AC |
1944 | /* The copy function takes the read lock and handles |
1945 | locking internally for this case */ | |
1da177e4 LT |
1946 | uncopied = copy_from_read_buf(tty, &b, &nr); |
1947 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
1948 | if (uncopied) { | |
1949 | retval = -EFAULT; | |
1950 | break; | |
1951 | } | |
1952 | } | |
1953 | ||
1954 | /* If there is enough space in the read buffer now, let the | |
1955 | * low-level driver know. We use n_tty_chars_in_buffer() to | |
1956 | * check the buffer, as it now knows about canonical mode. | |
1957 | * Otherwise, if the driver is throttled and the line is | |
1958 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
1959 | * we won't get any more characters. | |
1960 | */ | |
e91e52e4 PH |
1961 | while (1) { |
1962 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1963 | if (n_tty_chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
1964 | break; | |
1965 | if (!tty->count) | |
1966 | break; | |
55db4c64 | 1967 | n_tty_set_room(tty); |
e91e52e4 PH |
1968 | if (!tty_unthrottle_safe(tty)) |
1969 | break; | |
55db4c64 | 1970 | } |
e91e52e4 | 1971 | __tty_set_flow_change(tty, 0); |
1da177e4 LT |
1972 | |
1973 | if (b - buf >= minimum) | |
1974 | break; | |
1975 | if (time) | |
1976 | timeout = time; | |
1977 | } | |
bddc7152 | 1978 | mutex_unlock(&ldata->atomic_read_lock); |
1da177e4 LT |
1979 | remove_wait_queue(&tty->read_wait, &wait); |
1980 | ||
1981 | if (!waitqueue_active(&tty->read_wait)) | |
f6c8dbe6 | 1982 | ldata->minimum_to_wake = minimum; |
1da177e4 LT |
1983 | |
1984 | __set_current_state(TASK_RUNNING); | |
1985 | size = b - buf; | |
1986 | if (size) { | |
1987 | retval = size; | |
1988 | if (nr) | |
4edf1827 | 1989 | clear_bit(TTY_PUSH, &tty->flags); |
1da177e4 | 1990 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) |
bbd20759 | 1991 | goto do_it_again; |
1da177e4 | 1992 | |
55db4c64 | 1993 | n_tty_set_room(tty); |
1da177e4 LT |
1994 | return retval; |
1995 | } | |
1996 | ||
1997 | /** | |
11a96d18 | 1998 | * n_tty_write - write function for tty |
1da177e4 LT |
1999 | * @tty: tty device |
2000 | * @file: file object | |
2001 | * @buf: userspace buffer pointer | |
2002 | * @nr: size of I/O | |
2003 | * | |
a88a69c9 | 2004 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2005 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2006 | * and other such events. Since the receive code will echo characters, |
2007 | * thus calling driver write methods, the output_lock is used in | |
2008 | * the output processing functions called here as well as in the | |
2009 | * echo processing function to protect the column state and space | |
2010 | * left in the buffer. | |
1da177e4 LT |
2011 | * |
2012 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2013 | * |
2014 | * Locking: output_lock to protect column state and space left | |
2015 | * (note that the process_output*() functions take this | |
2016 | * lock themselves) | |
1da177e4 | 2017 | */ |
4edf1827 | 2018 | |
11a96d18 | 2019 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2020 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2021 | { |
2022 | const unsigned char *b = buf; | |
2023 | DECLARE_WAITQUEUE(wait, current); | |
2024 | int c; | |
2025 | ssize_t retval = 0; | |
2026 | ||
2027 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2028 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2029 | retval = tty_check_change(tty); | |
2030 | if (retval) | |
2031 | return retval; | |
2032 | } | |
2033 | ||
a88a69c9 JP |
2034 | /* Write out any echoed characters that are still pending */ |
2035 | process_echoes(tty); | |
300a6204 | 2036 | |
1da177e4 LT |
2037 | add_wait_queue(&tty->write_wait, &wait); |
2038 | while (1) { | |
2039 | set_current_state(TASK_INTERRUPTIBLE); | |
2040 | if (signal_pending(current)) { | |
2041 | retval = -ERESTARTSYS; | |
2042 | break; | |
2043 | } | |
2044 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2045 | retval = -EIO; | |
2046 | break; | |
2047 | } | |
582f5590 | 2048 | if (O_OPOST(tty)) { |
1da177e4 | 2049 | while (nr > 0) { |
a88a69c9 | 2050 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2051 | if (num < 0) { |
2052 | if (num == -EAGAIN) | |
2053 | break; | |
2054 | retval = num; | |
2055 | goto break_out; | |
2056 | } | |
2057 | b += num; | |
2058 | nr -= num; | |
2059 | if (nr == 0) | |
2060 | break; | |
2061 | c = *b; | |
a88a69c9 | 2062 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2063 | break; |
2064 | b++; nr--; | |
2065 | } | |
f34d7a5b AC |
2066 | if (tty->ops->flush_chars) |
2067 | tty->ops->flush_chars(tty); | |
1da177e4 | 2068 | } else { |
d6afe27b | 2069 | while (nr > 0) { |
f34d7a5b | 2070 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
2071 | if (c < 0) { |
2072 | retval = c; | |
2073 | goto break_out; | |
2074 | } | |
2075 | if (!c) | |
2076 | break; | |
2077 | b += c; | |
2078 | nr -= c; | |
1da177e4 | 2079 | } |
1da177e4 LT |
2080 | } |
2081 | if (!nr) | |
2082 | break; | |
2083 | if (file->f_flags & O_NONBLOCK) { | |
2084 | retval = -EAGAIN; | |
2085 | break; | |
2086 | } | |
2087 | schedule(); | |
2088 | } | |
2089 | break_out: | |
2090 | __set_current_state(TASK_RUNNING); | |
2091 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2092 | if (b - buf != nr && tty->fasync) |
2093 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
1da177e4 LT |
2094 | return (b - buf) ? b - buf : retval; |
2095 | } | |
2096 | ||
2097 | /** | |
11a96d18 | 2098 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2099 | * @tty: terminal device |
2100 | * @file: file accessing it | |
2101 | * @wait: poll table | |
2102 | * | |
2103 | * Called when the line discipline is asked to poll() for data or | |
2104 | * for special events. This code is not serialized with respect to | |
2105 | * other events save open/close. | |
2106 | * | |
2107 | * This code must be sure never to sleep through a hangup. | |
2108 | * Called without the kernel lock held - fine | |
1da177e4 | 2109 | */ |
4edf1827 | 2110 | |
11a96d18 | 2111 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2112 | poll_table *wait) |
1da177e4 | 2113 | { |
f6c8dbe6 | 2114 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2115 | unsigned int mask = 0; |
2116 | ||
2117 | poll_wait(file, &tty->read_wait, wait); | |
2118 | poll_wait(file, &tty->write_wait, wait); | |
2119 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2120 | mask |= POLLIN | POLLRDNORM; | |
2121 | if (tty->packet && tty->link->ctrl_status) | |
2122 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2123 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2124 | mask |= POLLHUP; | |
2125 | if (tty_hung_up_p(file)) | |
2126 | mask |= POLLHUP; | |
2127 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2128 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2129 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2130 | else |
f6c8dbe6 | 2131 | ldata->minimum_to_wake = 1; |
1da177e4 | 2132 | } |
f34d7a5b AC |
2133 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2134 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2135 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2136 | mask |= POLLOUT | POLLWRNORM; |
2137 | return mask; | |
2138 | } | |
2139 | ||
57c94121 | 2140 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 AC |
2141 | { |
2142 | int nr, head, tail; | |
2143 | ||
ba2e68ac | 2144 | if (!ldata->canon_data) |
47afa7a5 | 2145 | return 0; |
ba2e68ac JS |
2146 | head = ldata->canon_head; |
2147 | tail = ldata->read_tail; | |
47afa7a5 AC |
2148 | nr = (head - tail) & (N_TTY_BUF_SIZE-1); |
2149 | /* Skip EOF-chars.. */ | |
2150 | while (head != tail) { | |
3fe780b3 | 2151 | if (test_bit(tail, ldata->read_flags) && |
ba2e68ac | 2152 | ldata->read_buf[tail] == __DISABLED_CHAR) |
47afa7a5 AC |
2153 | nr--; |
2154 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
2155 | } | |
2156 | return nr; | |
2157 | } | |
2158 | ||
2159 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2160 | unsigned int cmd, unsigned long arg) | |
2161 | { | |
ba2e68ac | 2162 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2163 | int retval; |
2164 | ||
2165 | switch (cmd) { | |
2166 | case TIOCOUTQ: | |
2167 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2168 | case TIOCINQ: | |
17b82060 | 2169 | /* FIXME: Locking */ |
ba2e68ac | 2170 | retval = ldata->read_cnt; |
47afa7a5 | 2171 | if (L_ICANON(tty)) |
57c94121 | 2172 | retval = inq_canon(ldata); |
47afa7a5 AC |
2173 | return put_user(retval, (unsigned int __user *) arg); |
2174 | default: | |
2175 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2176 | } | |
2177 | } | |
2178 | ||
f6c8dbe6 PH |
2179 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2180 | { | |
2181 | struct n_tty_data *ldata = tty->disc_data; | |
2182 | ||
2183 | if (!waitqueue_active(&tty->read_wait)) { | |
2184 | if (on) | |
2185 | ldata->minimum_to_wake = 1; | |
2186 | else if (!tty->fasync) | |
2187 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2188 | } | |
2189 | } | |
2190 | ||
a352def2 | 2191 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2192 | .magic = TTY_LDISC_MAGIC, |
2193 | .name = "n_tty", | |
2194 | .open = n_tty_open, | |
2195 | .close = n_tty_close, | |
2196 | .flush_buffer = n_tty_flush_buffer, | |
2197 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2198 | .read = n_tty_read, |
2199 | .write = n_tty_write, | |
e10cc1df PF |
2200 | .ioctl = n_tty_ioctl, |
2201 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2202 | .poll = n_tty_poll, |
e10cc1df | 2203 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2204 | .write_wakeup = n_tty_write_wakeup, |
2205 | .fasync = n_tty_fasync, | |
1da177e4 | 2206 | }; |
572b9adb RG |
2207 | |
2208 | /** | |
2209 | * n_tty_inherit_ops - inherit N_TTY methods | |
2210 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2211 | * | |
593fb1ae | 2212 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2213 | * methods. |
2214 | */ | |
2215 | ||
2216 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2217 | { | |
2218 | *ops = tty_ldisc_N_TTY; | |
2219 | ops->owner = NULL; | |
2220 | ops->refcount = ops->flags = 0; | |
2221 | } | |
2222 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |