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