Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * n_tty.c --- implements the N_TTY line discipline. | |
4edf1827 | 3 | * |
1da177e4 LT |
4 | * This code used to be in tty_io.c, but things are getting hairy |
5 | * enough that it made sense to split things off. (The N_TTY | |
6 | * processing has changed so much that it's hardly recognizable, | |
7 | * anyway...) | |
8 | * | |
9 | * Note that the open routine for N_TTY is guaranteed never to return | |
10 | * an error. This is because Linux will fall back to setting a line | |
4edf1827 | 11 | * to N_TTY if it can not switch to any other line discipline. |
1da177e4 LT |
12 | * |
13 | * Written by Theodore Ts'o, Copyright 1994. | |
4edf1827 | 14 | * |
1da177e4 LT |
15 | * This file also contains code originally written by Linus Torvalds, |
16 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. | |
4edf1827 | 17 | * |
1da177e4 LT |
18 | * This file may be redistributed under the terms of the GNU General Public |
19 | * License. | |
20 | * | |
21 | * Reduced memory usage for older ARM systems - Russell King. | |
22 | * | |
4edf1827 | 23 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
1da177e4 LT |
24 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
25 | * who actually finally proved there really was a race. | |
26 | * | |
27 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to | |
28 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. | |
11a96d18 | 29 | * Also fixed a bug in BLOCKING mode where n_tty_write returns |
1da177e4 LT |
30 | * EAGAIN |
31 | */ | |
32 | ||
33 | #include <linux/types.h> | |
34 | #include <linux/major.h> | |
35 | #include <linux/errno.h> | |
36 | #include <linux/signal.h> | |
37 | #include <linux/fcntl.h> | |
38 | #include <linux/sched.h> | |
39 | #include <linux/interrupt.h> | |
40 | #include <linux/tty.h> | |
41 | #include <linux/timer.h> | |
42 | #include <linux/ctype.h> | |
43 | #include <linux/mm.h> | |
44 | #include <linux/string.h> | |
45 | #include <linux/slab.h> | |
46 | #include <linux/poll.h> | |
47 | #include <linux/bitops.h> | |
522ed776 MT |
48 | #include <linux/audit.h> |
49 | #include <linux/file.h> | |
300a6204 | 50 | #include <linux/uaccess.h> |
572b9adb | 51 | #include <linux/module.h> |
593fb1ae | 52 | #include <linux/ratelimit.h> |
1da177e4 | 53 | |
1da177e4 LT |
54 | |
55 | /* number of characters left in xmit buffer before select has we have room */ | |
56 | #define WAKEUP_CHARS 256 | |
57 | ||
58 | /* | |
59 | * This defines the low- and high-watermarks for throttling and | |
60 | * unthrottling the TTY driver. These watermarks are used for | |
61 | * controlling the space in the read buffer. | |
62 | */ | |
63 | #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ | |
bbd20759 | 64 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
1da177e4 | 65 | |
a88a69c9 JP |
66 | /* |
67 | * Special byte codes used in the echo buffer to represent operations | |
68 | * or special handling of characters. Bytes in the echo buffer that | |
69 | * are not part of such special blocks are treated as normal character | |
70 | * codes. | |
71 | */ | |
72 | #define ECHO_OP_START 0xff | |
73 | #define ECHO_OP_MOVE_BACK_COL 0x80 | |
74 | #define ECHO_OP_SET_CANON_COL 0x81 | |
75 | #define ECHO_OP_ERASE_TAB 0x82 | |
76 | ||
70ece7a7 | 77 | struct n_tty_data { |
53c5ee2c JS |
78 | unsigned int column; |
79 | unsigned long overrun_time; | |
80 | int num_overrun; | |
81 | ||
82 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; | |
83 | unsigned char echo_overrun:1; | |
3fe780b3 JS |
84 | |
85 | DECLARE_BITMAP(process_char_map, 256); | |
86 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); | |
ba2e68ac JS |
87 | |
88 | char *read_buf; | |
89 | int read_head; | |
90 | int read_tail; | |
91 | int read_cnt; | |
92 | ||
93 | unsigned char *echo_buf; | |
94 | unsigned int echo_pos; | |
95 | unsigned int echo_cnt; | |
96 | ||
97 | int canon_data; | |
98 | unsigned long canon_head; | |
99 | unsigned int canon_column; | |
bddc7152 JS |
100 | |
101 | struct mutex atomic_read_lock; | |
102 | struct mutex output_lock; | |
103 | struct mutex echo_lock; | |
98001214 | 104 | raw_spinlock_t read_lock; |
70ece7a7 JS |
105 | }; |
106 | ||
522ed776 MT |
107 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
108 | unsigned char __user *ptr) | |
109 | { | |
53c5ee2c JS |
110 | struct n_tty_data *ldata = tty->disc_data; |
111 | ||
112 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
113 | return put_user(x, ptr); |
114 | } | |
115 | ||
55db4c64 LT |
116 | /** |
117 | * n_tty_set__room - receive space | |
118 | * @tty: terminal | |
119 | * | |
120 | * Called by the driver to find out how much data it is | |
121 | * permitted to feed to the line discipline without any being lost | |
122 | * and thus to manage flow control. Not serialized. Answers for the | |
123 | * "instant". | |
124 | */ | |
125 | ||
126 | static void n_tty_set_room(struct tty_struct *tty) | |
127 | { | |
53c5ee2c | 128 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 129 | int left; |
55db4c64 LT |
130 | int old_left; |
131 | ||
ba2e68ac | 132 | /* ldata->read_cnt is not read locked ? */ |
090abf7b JA |
133 | if (I_PARMRK(tty)) { |
134 | /* Multiply read_cnt by 3, since each byte might take up to | |
135 | * three times as many spaces when PARMRK is set (depending on | |
136 | * its flags, e.g. parity error). */ | |
ba2e68ac | 137 | left = N_TTY_BUF_SIZE - ldata->read_cnt * 3 - 1; |
090abf7b | 138 | } else |
ba2e68ac | 139 | left = N_TTY_BUF_SIZE - ldata->read_cnt - 1; |
090abf7b | 140 | |
55db4c64 LT |
141 | /* |
142 | * If we are doing input canonicalization, and there are no | |
143 | * pending newlines, let characters through without limit, so | |
144 | * that erase characters will be handled. Other excess | |
145 | * characters will be beeped. | |
146 | */ | |
147 | if (left <= 0) | |
ba2e68ac | 148 | left = ldata->icanon && !ldata->canon_data; |
55db4c64 LT |
149 | old_left = tty->receive_room; |
150 | tty->receive_room = left; | |
151 | ||
152 | /* Did this open up the receive buffer? We may need to flip */ | |
ecbbfd44 JS |
153 | if (left && !old_left) { |
154 | WARN_RATELIMIT(tty->port->itty == NULL, | |
cadf7486 | 155 | "scheduling with invalid itty\n"); |
21622939 PH |
156 | /* see if ldisc has been killed - if so, this means that |
157 | * even though the ldisc has been halted and ->buf.work | |
158 | * cancelled, ->buf.work is about to be rescheduled | |
159 | */ | |
160 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
161 | "scheduling buffer work for halted ldisc\n"); | |
ecbbfd44 JS |
162 | schedule_work(&tty->port->buf.work); |
163 | } | |
55db4c64 LT |
164 | } |
165 | ||
57c94121 | 166 | static void put_tty_queue_nolock(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 167 | { |
ba2e68ac JS |
168 | if (ldata->read_cnt < N_TTY_BUF_SIZE) { |
169 | ldata->read_buf[ldata->read_head] = c; | |
170 | ldata->read_head = (ldata->read_head + 1) & (N_TTY_BUF_SIZE-1); | |
171 | ldata->read_cnt++; | |
1da177e4 LT |
172 | } |
173 | } | |
174 | ||
17b82060 AC |
175 | /** |
176 | * put_tty_queue - add character to tty | |
177 | * @c: character | |
57c94121 | 178 | * @ldata: n_tty data |
17b82060 AC |
179 | * |
180 | * Add a character to the tty read_buf queue. This is done under the | |
181 | * read_lock to serialize character addition and also to protect us | |
182 | * against parallel reads or flushes | |
183 | */ | |
184 | ||
57c94121 | 185 | static void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 LT |
186 | { |
187 | unsigned long flags; | |
188 | /* | |
189 | * The problem of stomping on the buffers ends here. | |
190 | * Why didn't anyone see this one coming? --AJK | |
191 | */ | |
98001214 | 192 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
57c94121 | 193 | put_tty_queue_nolock(c, ldata); |
98001214 | 194 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
195 | } |
196 | ||
1da177e4 LT |
197 | /** |
198 | * reset_buffer_flags - reset buffer state | |
199 | * @tty: terminal to reset | |
200 | * | |
25518c68 PH |
201 | * Reset the read buffer counters and clear the flags. |
202 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 AC |
203 | * |
204 | * Locking: tty_read_lock for read fields. | |
1da177e4 | 205 | */ |
a88a69c9 | 206 | |
b66f4fa5 | 207 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 LT |
208 | { |
209 | unsigned long flags; | |
210 | ||
98001214 | 211 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 212 | ldata->read_head = ldata->read_tail = ldata->read_cnt = 0; |
98001214 | 213 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
a88a69c9 | 214 | |
bddc7152 | 215 | mutex_lock(&ldata->echo_lock); |
ba2e68ac | 216 | ldata->echo_pos = ldata->echo_cnt = ldata->echo_overrun = 0; |
bddc7152 | 217 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 | 218 | |
ba2e68ac | 219 | ldata->canon_head = ldata->canon_data = ldata->erasing = 0; |
3fe780b3 | 220 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
1da177e4 LT |
221 | } |
222 | ||
a30737ab PH |
223 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
224 | { | |
225 | unsigned long flags; | |
226 | ||
227 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
228 | if (tty->link->packet) { | |
229 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
230 | wake_up_interruptible(&tty->link->read_wait); | |
231 | } | |
232 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
233 | } | |
234 | ||
1da177e4 LT |
235 | /** |
236 | * n_tty_flush_buffer - clean input queue | |
237 | * @tty: terminal device | |
238 | * | |
25518c68 PH |
239 | * Flush the input buffer. Called when the tty layer wants the |
240 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
241 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 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 | { |
b66f4fa5 PH |
248 | reset_buffer_flags(tty->disc_data); |
249 | n_tty_set_room(tty); | |
4edf1827 | 250 | |
a30737ab PH |
251 | if (tty->link) |
252 | n_tty_packet_mode_flush(tty); | |
1da177e4 LT |
253 | } |
254 | ||
255 | /** | |
256 | * n_tty_chars_in_buffer - report available bytes | |
257 | * @tty: tty device | |
258 | * | |
259 | * Report the number of characters buffered to be delivered to user | |
4edf1827 | 260 | * at this instant in time. |
17b82060 AC |
261 | * |
262 | * Locking: read_lock | |
1da177e4 | 263 | */ |
4edf1827 | 264 | |
1da177e4 LT |
265 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
266 | { | |
53c5ee2c | 267 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
268 | unsigned long flags; |
269 | ssize_t n = 0; | |
270 | ||
98001214 | 271 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
53c5ee2c | 272 | if (!ldata->icanon) { |
ba2e68ac JS |
273 | n = ldata->read_cnt; |
274 | } else if (ldata->canon_data) { | |
275 | n = (ldata->canon_head > ldata->read_tail) ? | |
276 | ldata->canon_head - ldata->read_tail : | |
277 | ldata->canon_head + (N_TTY_BUF_SIZE - ldata->read_tail); | |
1da177e4 | 278 | } |
98001214 | 279 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
280 | return n; |
281 | } | |
282 | ||
283 | /** | |
284 | * is_utf8_continuation - utf8 multibyte check | |
285 | * @c: byte to check | |
286 | * | |
287 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
288 | * character. We use this to correctly compute the on screen size | |
289 | * of the character when printing | |
290 | */ | |
4edf1827 | 291 | |
1da177e4 LT |
292 | static inline int is_utf8_continuation(unsigned char c) |
293 | { | |
294 | return (c & 0xc0) == 0x80; | |
295 | } | |
296 | ||
297 | /** | |
298 | * is_continuation - multibyte check | |
299 | * @c: byte to check | |
300 | * | |
301 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
302 | * character and the terminal is in unicode mode. | |
303 | */ | |
4edf1827 | 304 | |
1da177e4 LT |
305 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
306 | { | |
307 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
308 | } | |
309 | ||
310 | /** | |
a88a69c9 | 311 | * do_output_char - output one character |
1da177e4 LT |
312 | * @c: character (or partial unicode symbol) |
313 | * @tty: terminal device | |
a88a69c9 | 314 | * @space: space available in tty driver write buffer |
1da177e4 | 315 | * |
a88a69c9 JP |
316 | * This is a helper function that handles one output character |
317 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
318 | * doing OPOST processing and putting the results in the |
319 | * tty driver's write buffer. | |
a88a69c9 JP |
320 | * |
321 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
322 | * and NLDLY. They simply aren't relevant in the world today. | |
323 | * If you ever need them, add them here. | |
1da177e4 | 324 | * |
a88a69c9 JP |
325 | * Returns the number of bytes of buffer space used or -1 if |
326 | * no space left. | |
327 | * | |
328 | * Locking: should be called under the output_lock to protect | |
329 | * the column state and space left in the buffer | |
1da177e4 | 330 | */ |
4edf1827 | 331 | |
a88a69c9 | 332 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 333 | { |
53c5ee2c | 334 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 335 | int spaces; |
1da177e4 | 336 | |
1da177e4 LT |
337 | if (!space) |
338 | return -1; | |
300a6204 | 339 | |
a88a69c9 JP |
340 | switch (c) { |
341 | case '\n': | |
342 | if (O_ONLRET(tty)) | |
53c5ee2c | 343 | ldata->column = 0; |
a88a69c9 JP |
344 | if (O_ONLCR(tty)) { |
345 | if (space < 2) | |
346 | return -1; | |
ba2e68ac | 347 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 348 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
349 | return 2; |
350 | } | |
ba2e68ac | 351 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
352 | break; |
353 | case '\r': | |
53c5ee2c | 354 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
355 | return 0; |
356 | if (O_OCRNL(tty)) { | |
357 | c = '\n'; | |
358 | if (O_ONLRET(tty)) | |
ba2e68ac | 359 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 360 | break; |
a88a69c9 | 361 | } |
ba2e68ac | 362 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
363 | break; |
364 | case '\t': | |
53c5ee2c | 365 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
366 | if (O_TABDLY(tty) == XTABS) { |
367 | if (space < spaces) | |
368 | return -1; | |
53c5ee2c | 369 | ldata->column += spaces; |
a88a69c9 JP |
370 | tty->ops->write(tty, " ", spaces); |
371 | return spaces; | |
1da177e4 | 372 | } |
53c5ee2c | 373 | ldata->column += spaces; |
a88a69c9 JP |
374 | break; |
375 | case '\b': | |
53c5ee2c JS |
376 | if (ldata->column > 0) |
377 | ldata->column--; | |
a88a69c9 JP |
378 | break; |
379 | default: | |
a59c0d6f JP |
380 | if (!iscntrl(c)) { |
381 | if (O_OLCUC(tty)) | |
382 | c = toupper(c); | |
383 | if (!is_continuation(c, tty)) | |
53c5ee2c | 384 | ldata->column++; |
a59c0d6f | 385 | } |
a88a69c9 | 386 | break; |
1da177e4 | 387 | } |
a88a69c9 | 388 | |
f34d7a5b | 389 | tty_put_char(tty, c); |
a88a69c9 JP |
390 | return 1; |
391 | } | |
392 | ||
393 | /** | |
394 | * process_output - output post processor | |
395 | * @c: character (or partial unicode symbol) | |
396 | * @tty: terminal device | |
397 | * | |
ee5aa7b8 JP |
398 | * Output one character with OPOST processing. |
399 | * Returns -1 when the output device is full and the character | |
400 | * must be retried. | |
a88a69c9 JP |
401 | * |
402 | * Locking: output_lock to protect column state and space left | |
403 | * (also, this is called from n_tty_write under the | |
404 | * tty layer write lock) | |
405 | */ | |
406 | ||
407 | static int process_output(unsigned char c, struct tty_struct *tty) | |
408 | { | |
bddc7152 | 409 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
410 | int space, retval; |
411 | ||
bddc7152 | 412 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
413 | |
414 | space = tty_write_room(tty); | |
415 | retval = do_output_char(c, tty, space); | |
416 | ||
bddc7152 | 417 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
418 | if (retval < 0) |
419 | return -1; | |
420 | else | |
421 | return 0; | |
1da177e4 LT |
422 | } |
423 | ||
424 | /** | |
a88a69c9 | 425 | * process_output_block - block post processor |
1da177e4 | 426 | * @tty: terminal device |
ee5aa7b8 JP |
427 | * @buf: character buffer |
428 | * @nr: number of bytes to output | |
429 | * | |
430 | * Output a block of characters with OPOST processing. | |
431 | * Returns the number of characters output. | |
1da177e4 LT |
432 | * |
433 | * This path is used to speed up block console writes, among other | |
434 | * things when processing blocks of output data. It handles only | |
435 | * the simple cases normally found and helps to generate blocks of | |
436 | * symbols for the console driver and thus improve performance. | |
437 | * | |
a88a69c9 JP |
438 | * Locking: output_lock to protect column state and space left |
439 | * (also, this is called from n_tty_write under the | |
440 | * tty layer write lock) | |
1da177e4 | 441 | */ |
4edf1827 | 442 | |
a88a69c9 JP |
443 | static ssize_t process_output_block(struct tty_struct *tty, |
444 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 445 | { |
53c5ee2c | 446 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 447 | int space; |
bbd20759 | 448 | int i; |
1da177e4 LT |
449 | const unsigned char *cp; |
450 | ||
bddc7152 | 451 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 452 | |
f34d7a5b | 453 | space = tty_write_room(tty); |
300a6204 | 454 | if (!space) { |
bddc7152 | 455 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 456 | return 0; |
a88a69c9 | 457 | } |
1da177e4 LT |
458 | if (nr > space) |
459 | nr = space; | |
460 | ||
461 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
462 | unsigned char c = *cp; |
463 | ||
464 | switch (c) { | |
1da177e4 LT |
465 | case '\n': |
466 | if (O_ONLRET(tty)) | |
53c5ee2c | 467 | ldata->column = 0; |
1da177e4 LT |
468 | if (O_ONLCR(tty)) |
469 | goto break_out; | |
ba2e68ac | 470 | ldata->canon_column = ldata->column; |
1da177e4 LT |
471 | break; |
472 | case '\r': | |
53c5ee2c | 473 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
474 | goto break_out; |
475 | if (O_OCRNL(tty)) | |
476 | goto break_out; | |
ba2e68ac | 477 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
478 | break; |
479 | case '\t': | |
480 | goto break_out; | |
481 | case '\b': | |
53c5ee2c JS |
482 | if (ldata->column > 0) |
483 | ldata->column--; | |
1da177e4 LT |
484 | break; |
485 | default: | |
a59c0d6f JP |
486 | if (!iscntrl(c)) { |
487 | if (O_OLCUC(tty)) | |
488 | goto break_out; | |
489 | if (!is_continuation(c, tty)) | |
53c5ee2c | 490 | ldata->column++; |
a59c0d6f | 491 | } |
1da177e4 LT |
492 | break; |
493 | } | |
494 | } | |
495 | break_out: | |
f34d7a5b | 496 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 497 | |
bddc7152 | 498 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
499 | return i; |
500 | } | |
501 | ||
a88a69c9 JP |
502 | /** |
503 | * process_echoes - write pending echo characters | |
504 | * @tty: terminal device | |
505 | * | |
506 | * Write previously buffered echo (and other ldisc-generated) | |
507 | * characters to the tty. | |
508 | * | |
509 | * Characters generated by the ldisc (including echoes) need to | |
510 | * be buffered because the driver's write buffer can fill during | |
511 | * heavy program output. Echoing straight to the driver will | |
512 | * often fail under these conditions, causing lost characters and | |
513 | * resulting mismatches of ldisc state information. | |
514 | * | |
515 | * Since the ldisc state must represent the characters actually sent | |
516 | * to the driver at the time of the write, operations like certain | |
517 | * changes in column state are also saved in the buffer and executed | |
518 | * here. | |
519 | * | |
520 | * A circular fifo buffer is used so that the most recent characters | |
521 | * are prioritized. Also, when control characters are echoed with a | |
522 | * prefixed "^", the pair is treated atomically and thus not separated. | |
523 | * | |
524 | * Locking: output_lock to protect column state and space left, | |
525 | * echo_lock to protect the echo buffer | |
526 | */ | |
527 | ||
528 | static void process_echoes(struct tty_struct *tty) | |
529 | { | |
53c5ee2c | 530 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
531 | int space, nr; |
532 | unsigned char c; | |
533 | unsigned char *cp, *buf_end; | |
534 | ||
ba2e68ac | 535 | if (!ldata->echo_cnt) |
a88a69c9 JP |
536 | return; |
537 | ||
bddc7152 JS |
538 | mutex_lock(&ldata->output_lock); |
539 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
540 | |
541 | space = tty_write_room(tty); | |
542 | ||
ba2e68ac JS |
543 | buf_end = ldata->echo_buf + N_TTY_BUF_SIZE; |
544 | cp = ldata->echo_buf + ldata->echo_pos; | |
545 | nr = ldata->echo_cnt; | |
a88a69c9 JP |
546 | while (nr > 0) { |
547 | c = *cp; | |
548 | if (c == ECHO_OP_START) { | |
549 | unsigned char op; | |
550 | unsigned char *opp; | |
551 | int no_space_left = 0; | |
552 | ||
553 | /* | |
554 | * If the buffer byte is the start of a multi-byte | |
555 | * operation, get the next byte, which is either the | |
556 | * op code or a control character value. | |
557 | */ | |
558 | opp = cp + 1; | |
559 | if (opp == buf_end) | |
560 | opp -= N_TTY_BUF_SIZE; | |
561 | op = *opp; | |
300a6204 | 562 | |
a88a69c9 JP |
563 | switch (op) { |
564 | unsigned int num_chars, num_bs; | |
565 | ||
566 | case ECHO_OP_ERASE_TAB: | |
567 | if (++opp == buf_end) | |
568 | opp -= N_TTY_BUF_SIZE; | |
569 | num_chars = *opp; | |
570 | ||
571 | /* | |
572 | * Determine how many columns to go back | |
573 | * in order to erase the tab. | |
574 | * This depends on the number of columns | |
575 | * used by other characters within the tab | |
576 | * area. If this (modulo 8) count is from | |
577 | * the start of input rather than from a | |
578 | * previous tab, we offset by canon column. | |
579 | * Otherwise, tab spacing is normal. | |
580 | */ | |
581 | if (!(num_chars & 0x80)) | |
ba2e68ac | 582 | num_chars += ldata->canon_column; |
a88a69c9 JP |
583 | num_bs = 8 - (num_chars & 7); |
584 | ||
585 | if (num_bs > space) { | |
586 | no_space_left = 1; | |
587 | break; | |
588 | } | |
589 | space -= num_bs; | |
590 | while (num_bs--) { | |
591 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
592 | if (ldata->column > 0) |
593 | ldata->column--; | |
a88a69c9 JP |
594 | } |
595 | cp += 3; | |
596 | nr -= 3; | |
597 | break; | |
598 | ||
599 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 600 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
601 | cp += 2; |
602 | nr -= 2; | |
603 | break; | |
604 | ||
605 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
606 | if (ldata->column > 0) |
607 | ldata->column--; | |
a88a69c9 JP |
608 | cp += 2; |
609 | nr -= 2; | |
610 | break; | |
611 | ||
612 | case ECHO_OP_START: | |
613 | /* This is an escaped echo op start code */ | |
614 | if (!space) { | |
615 | no_space_left = 1; | |
616 | break; | |
617 | } | |
618 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 619 | ldata->column++; |
a88a69c9 JP |
620 | space--; |
621 | cp += 2; | |
622 | nr -= 2; | |
623 | break; | |
624 | ||
625 | default: | |
a88a69c9 | 626 | /* |
62b26358 JP |
627 | * If the op is not a special byte code, |
628 | * it is a ctrl char tagged to be echoed | |
629 | * as "^X" (where X is the letter | |
630 | * representing the control char). | |
631 | * Note that we must ensure there is | |
632 | * enough space for the whole ctrl pair. | |
633 | * | |
a88a69c9 | 634 | */ |
62b26358 JP |
635 | if (space < 2) { |
636 | no_space_left = 1; | |
637 | break; | |
638 | } | |
639 | tty_put_char(tty, '^'); | |
640 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 641 | ldata->column += 2; |
62b26358 | 642 | space -= 2; |
a88a69c9 JP |
643 | cp += 2; |
644 | nr -= 2; | |
645 | } | |
646 | ||
647 | if (no_space_left) | |
648 | break; | |
649 | } else { | |
ee5aa7b8 JP |
650 | if (O_OPOST(tty) && |
651 | !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
652 | int retval = do_output_char(c, tty, space); | |
653 | if (retval < 0) | |
654 | break; | |
655 | space -= retval; | |
656 | } else { | |
657 | if (!space) | |
658 | break; | |
659 | tty_put_char(tty, c); | |
660 | space -= 1; | |
661 | } | |
a88a69c9 JP |
662 | cp += 1; |
663 | nr -= 1; | |
664 | } | |
665 | ||
666 | /* When end of circular buffer reached, wrap around */ | |
667 | if (cp >= buf_end) | |
668 | cp -= N_TTY_BUF_SIZE; | |
669 | } | |
670 | ||
671 | if (nr == 0) { | |
ba2e68ac JS |
672 | ldata->echo_pos = 0; |
673 | ldata->echo_cnt = 0; | |
53c5ee2c | 674 | ldata->echo_overrun = 0; |
a88a69c9 | 675 | } else { |
ba2e68ac JS |
676 | int num_processed = ldata->echo_cnt - nr; |
677 | ldata->echo_pos += num_processed; | |
678 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; | |
679 | ldata->echo_cnt = nr; | |
a88a69c9 | 680 | if (num_processed > 0) |
53c5ee2c | 681 | ldata->echo_overrun = 0; |
a88a69c9 JP |
682 | } |
683 | ||
bddc7152 JS |
684 | mutex_unlock(&ldata->echo_lock); |
685 | mutex_unlock(&ldata->output_lock); | |
a88a69c9 JP |
686 | |
687 | if (tty->ops->flush_chars) | |
688 | tty->ops->flush_chars(tty); | |
689 | } | |
690 | ||
691 | /** | |
692 | * add_echo_byte - add a byte to the echo buffer | |
693 | * @c: unicode byte to echo | |
57c94121 | 694 | * @ldata: n_tty data |
a88a69c9 JP |
695 | * |
696 | * Add a character or operation byte to the echo buffer. | |
697 | * | |
698 | * Should be called under the echo lock to protect the echo buffer. | |
699 | */ | |
700 | ||
57c94121 | 701 | static void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 JP |
702 | { |
703 | int new_byte_pos; | |
704 | ||
ba2e68ac | 705 | if (ldata->echo_cnt == N_TTY_BUF_SIZE) { |
a88a69c9 | 706 | /* Circular buffer is already at capacity */ |
ba2e68ac | 707 | new_byte_pos = ldata->echo_pos; |
a88a69c9 JP |
708 | |
709 | /* | |
710 | * Since the buffer start position needs to be advanced, | |
711 | * be sure to step by a whole operation byte group. | |
712 | */ | |
ba2e68ac JS |
713 | if (ldata->echo_buf[ldata->echo_pos] == ECHO_OP_START) { |
714 | if (ldata->echo_buf[(ldata->echo_pos + 1) & | |
a88a69c9 JP |
715 | (N_TTY_BUF_SIZE - 1)] == |
716 | ECHO_OP_ERASE_TAB) { | |
ba2e68ac JS |
717 | ldata->echo_pos += 3; |
718 | ldata->echo_cnt -= 2; | |
a88a69c9 | 719 | } else { |
ba2e68ac JS |
720 | ldata->echo_pos += 2; |
721 | ldata->echo_cnt -= 1; | |
a88a69c9 JP |
722 | } |
723 | } else { | |
ba2e68ac | 724 | ldata->echo_pos++; |
a88a69c9 | 725 | } |
ba2e68ac | 726 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; |
a88a69c9 | 727 | |
53c5ee2c | 728 | ldata->echo_overrun = 1; |
a88a69c9 | 729 | } else { |
ba2e68ac | 730 | new_byte_pos = ldata->echo_pos + ldata->echo_cnt; |
a88a69c9 | 731 | new_byte_pos &= N_TTY_BUF_SIZE - 1; |
ba2e68ac | 732 | ldata->echo_cnt++; |
a88a69c9 JP |
733 | } |
734 | ||
ba2e68ac | 735 | ldata->echo_buf[new_byte_pos] = c; |
a88a69c9 JP |
736 | } |
737 | ||
738 | /** | |
739 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 740 | * @ldata: n_tty data |
a88a69c9 JP |
741 | * |
742 | * Add an operation to the echo buffer to move back one column. | |
743 | * | |
744 | * Locking: echo_lock to protect the echo buffer | |
745 | */ | |
746 | ||
57c94121 | 747 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 748 | { |
bddc7152 | 749 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
750 | add_echo_byte(ECHO_OP_START, ldata); |
751 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
bddc7152 | 752 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
753 | } |
754 | ||
755 | /** | |
756 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 757 | * @ldata: n_tty data |
a88a69c9 JP |
758 | * |
759 | * Add an operation to the echo buffer to set the canon column | |
760 | * to the current column. | |
761 | * | |
762 | * Locking: echo_lock to protect the echo buffer | |
763 | */ | |
764 | ||
57c94121 | 765 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 766 | { |
bddc7152 | 767 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
768 | add_echo_byte(ECHO_OP_START, ldata); |
769 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
bddc7152 | 770 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
771 | } |
772 | ||
773 | /** | |
774 | * echo_erase_tab - add operation to erase a tab | |
775 | * @num_chars: number of character columns already used | |
776 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 777 | * @ldata: n_tty data |
a88a69c9 JP |
778 | * |
779 | * Add an operation to the echo buffer to erase a tab. | |
780 | * | |
781 | * Called by the eraser function, which knows how many character | |
782 | * columns have been used since either a previous tab or the start | |
783 | * of input. This information will be used later, along with | |
784 | * canon column (if applicable), to go back the correct number | |
785 | * of columns. | |
786 | * | |
787 | * Locking: echo_lock to protect the echo buffer | |
788 | */ | |
789 | ||
790 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 791 | struct n_tty_data *ldata) |
a88a69c9 | 792 | { |
bddc7152 | 793 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 794 | |
57c94121 JS |
795 | add_echo_byte(ECHO_OP_START, ldata); |
796 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
797 | |
798 | /* We only need to know this modulo 8 (tab spacing) */ | |
799 | num_chars &= 7; | |
800 | ||
801 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
802 | if (after_tab) | |
803 | num_chars |= 0x80; | |
300a6204 | 804 | |
57c94121 | 805 | add_echo_byte(num_chars, ldata); |
a88a69c9 | 806 | |
bddc7152 | 807 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
808 | } |
809 | ||
810 | /** | |
811 | * echo_char_raw - echo a character raw | |
812 | * @c: unicode byte to echo | |
813 | * @tty: terminal device | |
814 | * | |
815 | * Echo user input back onto the screen. This must be called only when | |
816 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
817 | * | |
818 | * This variant does not treat control characters specially. | |
819 | * | |
820 | * Locking: echo_lock to protect the echo buffer | |
821 | */ | |
822 | ||
57c94121 | 823 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 824 | { |
bddc7152 | 825 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 826 | if (c == ECHO_OP_START) { |
57c94121 JS |
827 | add_echo_byte(ECHO_OP_START, ldata); |
828 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 829 | } else { |
57c94121 | 830 | add_echo_byte(c, ldata); |
a88a69c9 | 831 | } |
bddc7152 | 832 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 | 833 | } |
1da177e4 | 834 | |
1da177e4 | 835 | /** |
a88a69c9 | 836 | * echo_char - echo a character |
1da177e4 LT |
837 | * @c: unicode byte to echo |
838 | * @tty: terminal device | |
839 | * | |
4edf1827 | 840 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 841 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 842 | * |
62b26358 JP |
843 | * This variant tags control characters to be echoed as "^X" |
844 | * (where X is the letter representing the control char). | |
a88a69c9 JP |
845 | * |
846 | * Locking: echo_lock to protect the echo buffer | |
1da177e4 LT |
847 | */ |
848 | ||
849 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
850 | { | |
bddc7152 JS |
851 | struct n_tty_data *ldata = tty->disc_data; |
852 | ||
853 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
854 | |
855 | if (c == ECHO_OP_START) { | |
57c94121 JS |
856 | add_echo_byte(ECHO_OP_START, ldata); |
857 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 858 | } else { |
62b26358 | 859 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
860 | add_echo_byte(ECHO_OP_START, ldata); |
861 | add_echo_byte(c, ldata); | |
a88a69c9 JP |
862 | } |
863 | ||
bddc7152 | 864 | mutex_unlock(&ldata->echo_lock); |
1da177e4 LT |
865 | } |
866 | ||
17b82060 | 867 | /** |
a88a69c9 | 868 | * finish_erasing - complete erase |
57c94121 | 869 | * @ldata: n_tty data |
17b82060 | 870 | */ |
a88a69c9 | 871 | |
57c94121 | 872 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 873 | { |
53c5ee2c | 874 | if (ldata->erasing) { |
57c94121 | 875 | echo_char_raw('/', ldata); |
53c5ee2c | 876 | ldata->erasing = 0; |
1da177e4 LT |
877 | } |
878 | } | |
879 | ||
880 | /** | |
881 | * eraser - handle erase function | |
882 | * @c: character input | |
883 | * @tty: terminal device | |
884 | * | |
3a4fa0a2 | 885 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
886 | * present in the stream from the driver layer. Handles the complexities |
887 | * of UTF-8 multibyte symbols. | |
17b82060 | 888 | * |
a88a69c9 | 889 | * Locking: read_lock for tty buffers |
1da177e4 | 890 | */ |
4edf1827 | 891 | |
1da177e4 LT |
892 | static void eraser(unsigned char c, struct tty_struct *tty) |
893 | { | |
53c5ee2c | 894 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
895 | enum { ERASE, WERASE, KILL } kill_type; |
896 | int head, seen_alnums, cnt; | |
897 | unsigned long flags; | |
898 | ||
17b82060 | 899 | /* FIXME: locking needed ? */ |
ba2e68ac | 900 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 901 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
902 | return; |
903 | } | |
904 | if (c == ERASE_CHAR(tty)) | |
905 | kill_type = ERASE; | |
906 | else if (c == WERASE_CHAR(tty)) | |
907 | kill_type = WERASE; | |
908 | else { | |
909 | if (!L_ECHO(tty)) { | |
98001214 | 910 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 911 | ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) & |
1da177e4 | 912 | (N_TTY_BUF_SIZE - 1)); |
ba2e68ac | 913 | ldata->read_head = ldata->canon_head; |
98001214 | 914 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
915 | return; |
916 | } | |
917 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(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); |
57c94121 | 923 | finish_erasing(ldata); |
1da177e4 LT |
924 | echo_char(KILL_CHAR(tty), tty); |
925 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
926 | if (L_ECHOK(tty)) | |
57c94121 | 927 | echo_char_raw('\n', ldata); |
1da177e4 LT |
928 | return; |
929 | } | |
930 | kill_type = KILL; | |
931 | } | |
932 | ||
933 | seen_alnums = 0; | |
17b82060 | 934 | /* FIXME: Locking ?? */ |
ba2e68ac JS |
935 | while (ldata->read_head != ldata->canon_head) { |
936 | head = ldata->read_head; | |
1da177e4 LT |
937 | |
938 | /* erase a single possibly multibyte character */ | |
939 | do { | |
940 | head = (head - 1) & (N_TTY_BUF_SIZE-1); | |
ba2e68ac JS |
941 | c = ldata->read_buf[head]; |
942 | } while (is_continuation(c, tty) && head != ldata->canon_head); | |
1da177e4 LT |
943 | |
944 | /* do not partially erase */ | |
945 | if (is_continuation(c, tty)) | |
946 | break; | |
947 | ||
948 | if (kill_type == WERASE) { | |
949 | /* Equivalent to BSD's ALTWERASE. */ | |
950 | if (isalnum(c) || c == '_') | |
951 | seen_alnums++; | |
952 | else if (seen_alnums) | |
953 | break; | |
954 | } | |
ba2e68ac | 955 | cnt = (ldata->read_head - head) & (N_TTY_BUF_SIZE-1); |
98001214 | 956 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac JS |
957 | ldata->read_head = head; |
958 | ldata->read_cnt -= cnt; | |
98001214 | 959 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
960 | if (L_ECHO(tty)) { |
961 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 962 | if (!ldata->erasing) { |
57c94121 | 963 | echo_char_raw('\\', ldata); |
53c5ee2c | 964 | ldata->erasing = 1; |
1da177e4 LT |
965 | } |
966 | /* if cnt > 1, output a multi-byte character */ | |
967 | echo_char(c, tty); | |
968 | while (--cnt > 0) { | |
969 | head = (head+1) & (N_TTY_BUF_SIZE-1); | |
57c94121 JS |
970 | echo_char_raw(ldata->read_buf[head], |
971 | ldata); | |
972 | echo_move_back_col(ldata); | |
1da177e4 LT |
973 | } |
974 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
975 | echo_char(ERASE_CHAR(tty), tty); | |
976 | } else if (c == '\t') { | |
a88a69c9 JP |
977 | unsigned int num_chars = 0; |
978 | int after_tab = 0; | |
ba2e68ac | 979 | unsigned long tail = ldata->read_head; |
a88a69c9 JP |
980 | |
981 | /* | |
982 | * Count the columns used for characters | |
983 | * since the start of input or after a | |
984 | * previous tab. | |
985 | * This info is used to go back the correct | |
986 | * number of columns. | |
987 | */ | |
ba2e68ac | 988 | while (tail != ldata->canon_head) { |
a88a69c9 | 989 | tail = (tail-1) & (N_TTY_BUF_SIZE-1); |
ba2e68ac | 990 | c = ldata->read_buf[tail]; |
a88a69c9 JP |
991 | if (c == '\t') { |
992 | after_tab = 1; | |
993 | break; | |
300a6204 | 994 | } else if (iscntrl(c)) { |
1da177e4 | 995 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
996 | num_chars += 2; |
997 | } else if (!is_continuation(c, tty)) { | |
998 | num_chars++; | |
999 | } | |
1da177e4 | 1000 | } |
57c94121 | 1001 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1002 | } else { |
1003 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1004 | echo_char_raw('\b', ldata); |
1005 | echo_char_raw(' ', ldata); | |
1006 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1007 | } |
1008 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1009 | echo_char_raw('\b', ldata); |
1010 | echo_char_raw(' ', ldata); | |
1011 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1012 | } |
1013 | } | |
1014 | } | |
1015 | if (kill_type == ERASE) | |
1016 | break; | |
1017 | } | |
ba2e68ac | 1018 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1019 | finish_erasing(ldata); |
1da177e4 LT |
1020 | } |
1021 | ||
1022 | /** | |
1023 | * isig - handle the ISIG optio | |
1024 | * @sig: signal | |
1025 | * @tty: terminal | |
1da177e4 | 1026 | * |
8c985d18 PH |
1027 | * Called when a signal is being sent due to terminal input. |
1028 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1029 | * |
8c985d18 | 1030 | * Locking: ctrl_lock |
1da177e4 | 1031 | */ |
4edf1827 | 1032 | |
8c985d18 | 1033 | static inline void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1034 | { |
8c985d18 PH |
1035 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1036 | if (tty_pgrp) { | |
1037 | kill_pgrp(tty_pgrp, sig, 1); | |
1038 | put_pid(tty_pgrp); | |
1da177e4 LT |
1039 | } |
1040 | } | |
1041 | ||
1042 | /** | |
1043 | * n_tty_receive_break - handle break | |
1044 | * @tty: terminal | |
1045 | * | |
1046 | * An RS232 break event has been hit in the incoming bitstream. This | |
1047 | * can cause a variety of events depending upon the termios settings. | |
1048 | * | |
1049 | * Called from the receive_buf path so single threaded. | |
1050 | */ | |
4edf1827 | 1051 | |
1da177e4 LT |
1052 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1053 | { | |
57c94121 JS |
1054 | struct n_tty_data *ldata = tty->disc_data; |
1055 | ||
1da177e4 LT |
1056 | if (I_IGNBRK(tty)) |
1057 | return; | |
1058 | if (I_BRKINT(tty)) { | |
8c985d18 PH |
1059 | isig(SIGINT, tty); |
1060 | if (!L_NOFLSH(tty)) { | |
1061 | n_tty_flush_buffer(tty); | |
1062 | tty_driver_flush_buffer(tty); | |
1063 | } | |
1da177e4 LT |
1064 | return; |
1065 | } | |
1066 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1067 | put_tty_queue('\377', ldata); |
1068 | put_tty_queue('\0', ldata); | |
1da177e4 | 1069 | } |
57c94121 | 1070 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1071 | wake_up_interruptible(&tty->read_wait); |
1072 | } | |
1073 | ||
1074 | /** | |
1075 | * n_tty_receive_overrun - handle overrun reporting | |
1076 | * @tty: terminal | |
1077 | * | |
1078 | * Data arrived faster than we could process it. While the tty | |
1079 | * driver has flagged this the bits that were missed are gone | |
1080 | * forever. | |
1081 | * | |
1082 | * Called from the receive_buf path so single threaded. Does not | |
1083 | * need locking as num_overrun and overrun_time are function | |
1084 | * private. | |
1085 | */ | |
4edf1827 | 1086 | |
1da177e4 LT |
1087 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1088 | { | |
53c5ee2c | 1089 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1090 | char buf[64]; |
1091 | ||
53c5ee2c JS |
1092 | ldata->num_overrun++; |
1093 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1094 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1095 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1096 | tty_name(tty, buf), | |
53c5ee2c JS |
1097 | ldata->num_overrun); |
1098 | ldata->overrun_time = jiffies; | |
1099 | ldata->num_overrun = 0; | |
1da177e4 LT |
1100 | } |
1101 | } | |
1102 | ||
1103 | /** | |
1104 | * n_tty_receive_parity_error - error notifier | |
1105 | * @tty: terminal device | |
1106 | * @c: character | |
1107 | * | |
1108 | * Process a parity error and queue the right data to indicate | |
3a4fa0a2 | 1109 | * the error case if necessary. Locking as per n_tty_receive_buf. |
1da177e4 LT |
1110 | */ |
1111 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1112 | unsigned char c) | |
1113 | { | |
57c94121 JS |
1114 | struct n_tty_data *ldata = tty->disc_data; |
1115 | ||
4edf1827 | 1116 | if (I_IGNPAR(tty)) |
1da177e4 | 1117 | return; |
1da177e4 | 1118 | if (I_PARMRK(tty)) { |
57c94121 JS |
1119 | put_tty_queue('\377', ldata); |
1120 | put_tty_queue('\0', ldata); | |
1121 | put_tty_queue(c, ldata); | |
1da177e4 | 1122 | } else if (I_INPCK(tty)) |
57c94121 | 1123 | put_tty_queue('\0', ldata); |
1da177e4 | 1124 | else |
57c94121 | 1125 | put_tty_queue(c, ldata); |
1da177e4 LT |
1126 | wake_up_interruptible(&tty->read_wait); |
1127 | } | |
1128 | ||
1129 | /** | |
1130 | * n_tty_receive_char - perform processing | |
1131 | * @tty: terminal device | |
1132 | * @c: character | |
1133 | * | |
1134 | * Process an individual character of input received from the driver. | |
4edf1827 | 1135 | * This is serialized with respect to itself by the rules for the |
1da177e4 LT |
1136 | * driver above. |
1137 | */ | |
1138 | ||
1139 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1140 | { | |
53c5ee2c | 1141 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1142 | unsigned long flags; |
acc71bba | 1143 | int parmrk; |
1da177e4 | 1144 | |
53c5ee2c | 1145 | if (ldata->raw) { |
57c94121 | 1146 | put_tty_queue(c, ldata); |
1da177e4 LT |
1147 | return; |
1148 | } | |
4edf1827 | 1149 | |
1da177e4 LT |
1150 | if (I_ISTRIP(tty)) |
1151 | c &= 0x7f; | |
1152 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1153 | c = tolower(c); |
1da177e4 | 1154 | |
26df6d13 | 1155 | if (L_EXTPROC(tty)) { |
57c94121 | 1156 | put_tty_queue(c, ldata); |
26df6d13 | 1157 | return; |
1158 | } | |
1159 | ||
54d2a37e | 1160 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1161 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1162 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1163 | start_tty(tty); |
a88a69c9 JP |
1164 | process_echoes(tty); |
1165 | } | |
54d2a37e | 1166 | |
1da177e4 LT |
1167 | if (tty->closing) { |
1168 | if (I_IXON(tty)) { | |
a88a69c9 | 1169 | if (c == START_CHAR(tty)) { |
1da177e4 | 1170 | start_tty(tty); |
a88a69c9 | 1171 | process_echoes(tty); |
300a6204 | 1172 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1173 | stop_tty(tty); |
1174 | } | |
1175 | return; | |
1176 | } | |
1177 | ||
1178 | /* | |
1179 | * If the previous character was LNEXT, or we know that this | |
1180 | * character is not one of the characters that we'll have to | |
1181 | * handle specially, do shortcut processing to speed things | |
1182 | * up. | |
1183 | */ | |
3fe780b3 | 1184 | if (!test_bit(c, ldata->process_char_map) || ldata->lnext) { |
53c5ee2c | 1185 | ldata->lnext = 0; |
acc71bba | 1186 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ba2e68ac | 1187 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1188 | /* beep if no space */ |
7e94b1d9 JP |
1189 | if (L_ECHO(tty)) |
1190 | process_output('\a', tty); | |
acc71bba JP |
1191 | return; |
1192 | } | |
1193 | if (L_ECHO(tty)) { | |
57c94121 | 1194 | finish_erasing(ldata); |
1da177e4 | 1195 | /* Record the column of first canon char. */ |
ba2e68ac | 1196 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1197 | echo_set_canon_col(ldata); |
1da177e4 | 1198 | echo_char(c, tty); |
a88a69c9 | 1199 | process_echoes(tty); |
1da177e4 | 1200 | } |
acc71bba | 1201 | if (parmrk) |
57c94121 JS |
1202 | put_tty_queue(c, ldata); |
1203 | put_tty_queue(c, ldata); | |
1da177e4 LT |
1204 | return; |
1205 | } | |
4edf1827 | 1206 | |
1da177e4 LT |
1207 | if (I_IXON(tty)) { |
1208 | if (c == START_CHAR(tty)) { | |
1209 | start_tty(tty); | |
a88a69c9 | 1210 | process_echoes(tty); |
1da177e4 LT |
1211 | return; |
1212 | } | |
1213 | if (c == STOP_CHAR(tty)) { | |
1214 | stop_tty(tty); | |
1215 | return; | |
1216 | } | |
1217 | } | |
575537b3 | 1218 | |
1da177e4 LT |
1219 | if (L_ISIG(tty)) { |
1220 | int signal; | |
1221 | signal = SIGINT; | |
1222 | if (c == INTR_CHAR(tty)) | |
1223 | goto send_signal; | |
1224 | signal = SIGQUIT; | |
1225 | if (c == QUIT_CHAR(tty)) | |
1226 | goto send_signal; | |
1227 | signal = SIGTSTP; | |
1228 | if (c == SUSP_CHAR(tty)) { | |
1229 | send_signal: | |
ec5b1157 JP |
1230 | if (!L_NOFLSH(tty)) { |
1231 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1232 | tty_driver_flush_buffer(tty); |
ec5b1157 | 1233 | } |
a88a69c9 JP |
1234 | if (I_IXON(tty)) |
1235 | start_tty(tty); | |
1236 | if (L_ECHO(tty)) { | |
ec5b1157 | 1237 | echo_char(c, tty); |
a88a69c9 JP |
1238 | process_echoes(tty); |
1239 | } | |
8c985d18 | 1240 | isig(signal, tty); |
1da177e4 LT |
1241 | return; |
1242 | } | |
1243 | } | |
575537b3 JP |
1244 | |
1245 | if (c == '\r') { | |
1246 | if (I_IGNCR(tty)) | |
1247 | return; | |
1248 | if (I_ICRNL(tty)) | |
1249 | c = '\n'; | |
1250 | } else if (c == '\n' && I_INLCR(tty)) | |
1251 | c = '\r'; | |
1252 | ||
53c5ee2c | 1253 | if (ldata->icanon) { |
1da177e4 LT |
1254 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1255 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1256 | eraser(c, tty); | |
a88a69c9 | 1257 | process_echoes(tty); |
1da177e4 LT |
1258 | return; |
1259 | } | |
1260 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1261 | ldata->lnext = 1; |
1da177e4 | 1262 | if (L_ECHO(tty)) { |
57c94121 | 1263 | finish_erasing(ldata); |
1da177e4 | 1264 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1265 | echo_char_raw('^', ldata); |
1266 | echo_char_raw('\b', ldata); | |
a88a69c9 | 1267 | process_echoes(tty); |
1da177e4 LT |
1268 | } |
1269 | } | |
1270 | return; | |
1271 | } | |
1272 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1273 | L_IEXTEN(tty)) { | |
ba2e68ac | 1274 | unsigned long tail = ldata->canon_head; |
1da177e4 | 1275 | |
57c94121 | 1276 | finish_erasing(ldata); |
1da177e4 | 1277 | echo_char(c, tty); |
57c94121 | 1278 | echo_char_raw('\n', ldata); |
ba2e68ac JS |
1279 | while (tail != ldata->read_head) { |
1280 | echo_char(ldata->read_buf[tail], tty); | |
1da177e4 LT |
1281 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); |
1282 | } | |
a88a69c9 | 1283 | process_echoes(tty); |
1da177e4 LT |
1284 | return; |
1285 | } | |
1286 | if (c == '\n') { | |
ba2e68ac | 1287 | if (ldata->read_cnt >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1288 | if (L_ECHO(tty)) |
1289 | process_output('\a', tty); | |
acc71bba JP |
1290 | return; |
1291 | } | |
1292 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
57c94121 | 1293 | echo_char_raw('\n', ldata); |
a88a69c9 | 1294 | process_echoes(tty); |
1da177e4 LT |
1295 | } |
1296 | goto handle_newline; | |
1297 | } | |
1298 | if (c == EOF_CHAR(tty)) { | |
ba2e68ac | 1299 | if (ldata->read_cnt >= N_TTY_BUF_SIZE) |
acc71bba | 1300 | return; |
ba2e68ac | 1301 | if (ldata->canon_head != ldata->read_head) |
4edf1827 | 1302 | set_bit(TTY_PUSH, &tty->flags); |
1da177e4 LT |
1303 | c = __DISABLED_CHAR; |
1304 | goto handle_newline; | |
1305 | } | |
1306 | if ((c == EOL_CHAR(tty)) || | |
1307 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1308 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1309 | ? 1 : 0; | |
ba2e68ac | 1310 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) { |
7e94b1d9 JP |
1311 | if (L_ECHO(tty)) |
1312 | process_output('\a', tty); | |
acc71bba JP |
1313 | return; |
1314 | } | |
1da177e4 LT |
1315 | /* |
1316 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1317 | */ | |
1318 | if (L_ECHO(tty)) { | |
1da177e4 | 1319 | /* Record the column of first canon char. */ |
ba2e68ac | 1320 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1321 | echo_set_canon_col(ldata); |
1da177e4 | 1322 | echo_char(c, tty); |
a88a69c9 | 1323 | process_echoes(tty); |
1da177e4 LT |
1324 | } |
1325 | /* | |
1326 | * XXX does PARMRK doubling happen for | |
1327 | * EOL_CHAR and EOL2_CHAR? | |
1328 | */ | |
acc71bba | 1329 | if (parmrk) |
57c94121 | 1330 | put_tty_queue(c, ldata); |
1da177e4 | 1331 | |
4edf1827 | 1332 | handle_newline: |
98001214 | 1333 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 1334 | set_bit(ldata->read_head, ldata->read_flags); |
57c94121 | 1335 | put_tty_queue_nolock(c, ldata); |
ba2e68ac JS |
1336 | ldata->canon_head = ldata->read_head; |
1337 | ldata->canon_data++; | |
98001214 | 1338 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1339 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1340 | if (waitqueue_active(&tty->read_wait)) | |
1341 | wake_up_interruptible(&tty->read_wait); | |
1342 | return; | |
1343 | } | |
1344 | } | |
4edf1827 | 1345 | |
acc71bba | 1346 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ba2e68ac | 1347 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1348 | /* beep if no space */ |
7e94b1d9 JP |
1349 | if (L_ECHO(tty)) |
1350 | process_output('\a', tty); | |
acc71bba JP |
1351 | return; |
1352 | } | |
1353 | if (L_ECHO(tty)) { | |
57c94121 | 1354 | finish_erasing(ldata); |
1da177e4 | 1355 | if (c == '\n') |
57c94121 | 1356 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1357 | else { |
1358 | /* Record the column of first canon char. */ | |
ba2e68ac | 1359 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1360 | echo_set_canon_col(ldata); |
1da177e4 LT |
1361 | echo_char(c, tty); |
1362 | } | |
a88a69c9 | 1363 | process_echoes(tty); |
1da177e4 LT |
1364 | } |
1365 | ||
acc71bba | 1366 | if (parmrk) |
57c94121 | 1367 | put_tty_queue(c, ldata); |
1da177e4 | 1368 | |
57c94121 | 1369 | put_tty_queue(c, ldata); |
4edf1827 | 1370 | } |
1da177e4 | 1371 | |
1da177e4 LT |
1372 | |
1373 | /** | |
1374 | * n_tty_write_wakeup - asynchronous I/O notifier | |
1375 | * @tty: tty device | |
1376 | * | |
1377 | * Required for the ptys, serial driver etc. since processes | |
1378 | * that attach themselves to the master and rely on ASYNC | |
1379 | * IO must be woken up | |
1380 | */ | |
1381 | ||
1382 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
1383 | { | |
ff8cb0fd | 1384 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) |
1da177e4 | 1385 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); |
1da177e4 LT |
1386 | } |
1387 | ||
1388 | /** | |
1389 | * n_tty_receive_buf - data receive | |
1390 | * @tty: terminal device | |
1391 | * @cp: buffer | |
1392 | * @fp: flag buffer | |
1393 | * @count: characters | |
1394 | * | |
1395 | * Called by the terminal driver when a block of characters has | |
1396 | * been received. This function must be called from soft contexts | |
1397 | * not from interrupt context. The driver is responsible for making | |
1398 | * calls one at a time and in order (or using flush_to_ldisc) | |
1399 | */ | |
4edf1827 | 1400 | |
55db4c64 LT |
1401 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1402 | char *fp, int count) | |
1da177e4 | 1403 | { |
53c5ee2c | 1404 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1405 | const unsigned char *p; |
1406 | char *f, flags = TTY_NORMAL; | |
1407 | int i; | |
1408 | char buf[64]; | |
1409 | unsigned long cpuflags; | |
1410 | ||
53c5ee2c | 1411 | if (ldata->real_raw) { |
98001214 | 1412 | raw_spin_lock_irqsave(&ldata->read_lock, cpuflags); |
ba2e68ac JS |
1413 | i = min(N_TTY_BUF_SIZE - ldata->read_cnt, |
1414 | N_TTY_BUF_SIZE - ldata->read_head); | |
1da177e4 | 1415 | i = min(count, i); |
ba2e68ac JS |
1416 | memcpy(ldata->read_buf + ldata->read_head, cp, i); |
1417 | ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1418 | ldata->read_cnt += i; | |
1da177e4 LT |
1419 | cp += i; |
1420 | count -= i; | |
1421 | ||
ba2e68ac JS |
1422 | i = min(N_TTY_BUF_SIZE - ldata->read_cnt, |
1423 | N_TTY_BUF_SIZE - ldata->read_head); | |
1da177e4 | 1424 | i = min(count, i); |
ba2e68ac JS |
1425 | memcpy(ldata->read_buf + ldata->read_head, cp, i); |
1426 | ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1427 | ldata->read_cnt += i; | |
98001214 | 1428 | raw_spin_unlock_irqrestore(&ldata->read_lock, cpuflags); |
1da177e4 | 1429 | } else { |
4edf1827 | 1430 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1431 | if (f) |
1432 | flags = *f++; | |
1433 | switch (flags) { | |
1434 | case TTY_NORMAL: | |
1435 | n_tty_receive_char(tty, *p); | |
1436 | break; | |
1437 | case TTY_BREAK: | |
1438 | n_tty_receive_break(tty); | |
1439 | break; | |
1440 | case TTY_PARITY: | |
1441 | case TTY_FRAME: | |
1442 | n_tty_receive_parity_error(tty, *p); | |
1443 | break; | |
1444 | case TTY_OVERRUN: | |
1445 | n_tty_receive_overrun(tty); | |
1446 | break; | |
1447 | default: | |
4edf1827 | 1448 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1449 | tty_name(tty, buf), flags); |
1450 | break; | |
1451 | } | |
1452 | } | |
f34d7a5b AC |
1453 | if (tty->ops->flush_chars) |
1454 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1455 | } |
1456 | ||
55db4c64 LT |
1457 | n_tty_set_room(tty); |
1458 | ||
ba2e68ac | 1459 | if ((!ldata->icanon && (ldata->read_cnt >= tty->minimum_to_wake)) || |
26df6d13 | 1460 | L_EXTPROC(tty)) { |
1da177e4 LT |
1461 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1462 | if (waitqueue_active(&tty->read_wait)) | |
1463 | wake_up_interruptible(&tty->read_wait); | |
1464 | } | |
1465 | ||
1466 | /* | |
1467 | * Check the remaining room for the input canonicalization | |
1468 | * mode. We don't want to throttle the driver if we're in | |
1469 | * canonical mode and don't have a newline yet! | |
1470 | */ | |
e91e52e4 PH |
1471 | while (1) { |
1472 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
1473 | if (tty->receive_room >= TTY_THRESHOLD_THROTTLE) | |
1474 | break; | |
1475 | if (!tty_throttle_safe(tty)) | |
1476 | break; | |
1477 | } | |
1478 | __tty_set_flow_change(tty, 0); | |
1da177e4 LT |
1479 | } |
1480 | ||
1481 | int is_ignored(int sig) | |
1482 | { | |
1483 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1484 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1485 | } |
1486 | ||
1487 | /** | |
1488 | * n_tty_set_termios - termios data changed | |
1489 | * @tty: terminal | |
1490 | * @old: previous data | |
1491 | * | |
1492 | * Called by the tty layer when the user changes termios flags so | |
1493 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1494 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1495 | * guaranteed that this function will not be re-entered or in progress |
1496 | * when the ldisc is closed. | |
17b82060 AC |
1497 | * |
1498 | * Locking: Caller holds tty->termios_mutex | |
1da177e4 | 1499 | */ |
4edf1827 AC |
1500 | |
1501 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1502 | { |
53c5ee2c | 1503 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1504 | int canon_change = 1; |
47afa7a5 AC |
1505 | |
1506 | if (old) | |
adc8d746 | 1507 | canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON; |
47afa7a5 | 1508 | if (canon_change) { |
3fe780b3 | 1509 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
ba2e68ac JS |
1510 | ldata->canon_head = ldata->read_tail; |
1511 | ldata->canon_data = 0; | |
53c5ee2c | 1512 | ldata->erasing = 0; |
47afa7a5 AC |
1513 | } |
1514 | ||
ba2e68ac | 1515 | if (canon_change && !L_ICANON(tty) && ldata->read_cnt) |
47afa7a5 | 1516 | wake_up_interruptible(&tty->read_wait); |
4edf1827 | 1517 | |
53c5ee2c | 1518 | ldata->icanon = (L_ICANON(tty) != 0); |
1da177e4 | 1519 | if (test_bit(TTY_HW_COOK_IN, &tty->flags)) { |
53c5ee2c JS |
1520 | ldata->raw = 1; |
1521 | ldata->real_raw = 1; | |
55db4c64 | 1522 | n_tty_set_room(tty); |
1da177e4 LT |
1523 | return; |
1524 | } | |
1525 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || | |
1526 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1527 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1528 | I_PARMRK(tty)) { | |
3fe780b3 | 1529 | bitmap_zero(ldata->process_char_map, 256); |
1da177e4 LT |
1530 | |
1531 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
3fe780b3 | 1532 | set_bit('\r', ldata->process_char_map); |
1da177e4 | 1533 | if (I_INLCR(tty)) |
3fe780b3 | 1534 | set_bit('\n', ldata->process_char_map); |
1da177e4 LT |
1535 | |
1536 | if (L_ICANON(tty)) { | |
3fe780b3 JS |
1537 | set_bit(ERASE_CHAR(tty), ldata->process_char_map); |
1538 | set_bit(KILL_CHAR(tty), ldata->process_char_map); | |
1539 | set_bit(EOF_CHAR(tty), ldata->process_char_map); | |
1540 | set_bit('\n', ldata->process_char_map); | |
1541 | set_bit(EOL_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1542 | if (L_IEXTEN(tty)) { |
1543 | set_bit(WERASE_CHAR(tty), | |
3fe780b3 | 1544 | ldata->process_char_map); |
1da177e4 | 1545 | set_bit(LNEXT_CHAR(tty), |
3fe780b3 | 1546 | ldata->process_char_map); |
1da177e4 | 1547 | set_bit(EOL2_CHAR(tty), |
3fe780b3 | 1548 | ldata->process_char_map); |
1da177e4 LT |
1549 | if (L_ECHO(tty)) |
1550 | set_bit(REPRINT_CHAR(tty), | |
3fe780b3 | 1551 | ldata->process_char_map); |
1da177e4 LT |
1552 | } |
1553 | } | |
1554 | if (I_IXON(tty)) { | |
3fe780b3 JS |
1555 | set_bit(START_CHAR(tty), ldata->process_char_map); |
1556 | set_bit(STOP_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1557 | } |
1558 | if (L_ISIG(tty)) { | |
3fe780b3 JS |
1559 | set_bit(INTR_CHAR(tty), ldata->process_char_map); |
1560 | set_bit(QUIT_CHAR(tty), ldata->process_char_map); | |
1561 | set_bit(SUSP_CHAR(tty), ldata->process_char_map); | |
1da177e4 | 1562 | } |
3fe780b3 | 1563 | clear_bit(__DISABLED_CHAR, ldata->process_char_map); |
53c5ee2c JS |
1564 | ldata->raw = 0; |
1565 | ldata->real_raw = 0; | |
1da177e4 | 1566 | } else { |
53c5ee2c | 1567 | ldata->raw = 1; |
1da177e4 LT |
1568 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1569 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1570 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1571 | ldata->real_raw = 1; |
1da177e4 | 1572 | else |
53c5ee2c | 1573 | ldata->real_raw = 0; |
1da177e4 | 1574 | } |
55db4c64 | 1575 | n_tty_set_room(tty); |
dab73b4e WY |
1576 | /* |
1577 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1578 | * been stopped by STOP_CHAR(tty) before it. | |
1579 | */ | |
1580 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { | |
1581 | start_tty(tty); | |
1582 | } | |
1583 | ||
f34d7a5b AC |
1584 | /* The termios change make the tty ready for I/O */ |
1585 | wake_up_interruptible(&tty->write_wait); | |
1586 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1587 | } |
1588 | ||
1589 | /** | |
1590 | * n_tty_close - close the ldisc for this tty | |
1591 | * @tty: device | |
1592 | * | |
4edf1827 AC |
1593 | * Called from the terminal layer when this line discipline is |
1594 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1595 | * discipline change. The function will not be called while other |
1596 | * ldisc methods are in progress. | |
1597 | */ | |
4edf1827 | 1598 | |
1da177e4 LT |
1599 | static void n_tty_close(struct tty_struct *tty) |
1600 | { | |
70ece7a7 JS |
1601 | struct n_tty_data *ldata = tty->disc_data; |
1602 | ||
79901317 PH |
1603 | if (tty->link) |
1604 | n_tty_packet_mode_flush(tty); | |
1605 | ||
ba2e68ac JS |
1606 | kfree(ldata->read_buf); |
1607 | kfree(ldata->echo_buf); | |
70ece7a7 | 1608 | kfree(ldata); |
70ece7a7 | 1609 | tty->disc_data = NULL; |
1da177e4 LT |
1610 | } |
1611 | ||
1612 | /** | |
1613 | * n_tty_open - open an ldisc | |
1614 | * @tty: terminal to open | |
1615 | * | |
4edf1827 | 1616 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1617 | * terminal device. Can sleep. Called serialized so that no |
1618 | * other events will occur in parallel. No further open will occur | |
1619 | * until a close. | |
1620 | */ | |
1621 | ||
1622 | static int n_tty_open(struct tty_struct *tty) | |
1623 | { | |
70ece7a7 JS |
1624 | struct n_tty_data *ldata; |
1625 | ||
1626 | ldata = kzalloc(sizeof(*ldata), GFP_KERNEL); | |
1627 | if (!ldata) | |
1628 | goto err; | |
1629 | ||
53c5ee2c | 1630 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1631 | mutex_init(&ldata->atomic_read_lock); |
1632 | mutex_init(&ldata->output_lock); | |
1633 | mutex_init(&ldata->echo_lock); | |
98001214 | 1634 | raw_spin_lock_init(&ldata->read_lock); |
53c5ee2c | 1635 | |
a88a69c9 | 1636 | /* These are ugly. Currently a malloc failure here can panic */ |
ba2e68ac JS |
1637 | ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1638 | ldata->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); | |
1639 | if (!ldata->read_buf || !ldata->echo_buf) | |
b91939f5 | 1640 | goto err_free_bufs; |
0b4068a1 | 1641 | |
70ece7a7 | 1642 | tty->disc_data = ldata; |
b66f4fa5 | 1643 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1644 | ldata->column = 0; |
1da177e4 LT |
1645 | tty->minimum_to_wake = 1; |
1646 | tty->closing = 0; | |
b66f4fa5 PH |
1647 | /* indicate buffer work may resume */ |
1648 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1649 | n_tty_set_termios(tty, NULL); | |
1650 | tty_unthrottle(tty); | |
70ece7a7 | 1651 | |
1da177e4 | 1652 | return 0; |
b91939f5 | 1653 | err_free_bufs: |
ba2e68ac JS |
1654 | kfree(ldata->read_buf); |
1655 | kfree(ldata->echo_buf); | |
70ece7a7 JS |
1656 | kfree(ldata); |
1657 | err: | |
b91939f5 | 1658 | return -ENOMEM; |
1da177e4 LT |
1659 | } |
1660 | ||
1661 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1662 | { | |
53c5ee2c JS |
1663 | struct n_tty_data *ldata = tty->disc_data; |
1664 | ||
e043e42b | 1665 | tty_flush_to_ldisc(tty); |
53c5ee2c | 1666 | if (ldata->icanon && !L_EXTPROC(tty)) { |
ba2e68ac | 1667 | if (ldata->canon_data) |
1da177e4 | 1668 | return 1; |
ba2e68ac | 1669 | } else if (ldata->read_cnt >= (amt ? amt : 1)) |
1da177e4 LT |
1670 | return 1; |
1671 | ||
1672 | return 0; | |
1673 | } | |
1674 | ||
1675 | /** | |
bbd20759 | 1676 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1677 | * @tty: terminal device |
1678 | * @b: user data | |
1679 | * @nr: size of data | |
1680 | * | |
11a96d18 | 1681 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1682 | * ICANON is off; it copies characters straight from the tty queue to |
1683 | * user space directly. It can be profitably called twice; once to | |
1684 | * drain the space from the tail pointer to the (physical) end of the | |
1685 | * buffer, and once to drain the space from the (physical) beginning of | |
1686 | * the buffer to head pointer. | |
1687 | * | |
bddc7152 | 1688 | * Called under the ldata->atomic_read_lock sem |
1da177e4 LT |
1689 | * |
1690 | */ | |
4edf1827 | 1691 | |
33f0f88f | 1692 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1693 | unsigned char __user **b, |
1694 | size_t *nr) | |
1695 | ||
1696 | { | |
53c5ee2c | 1697 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1698 | int retval; |
1699 | size_t n; | |
1700 | unsigned long flags; | |
3fa10cc8 | 1701 | bool is_eof; |
1da177e4 LT |
1702 | |
1703 | retval = 0; | |
98001214 | 1704 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 1705 | n = min(ldata->read_cnt, N_TTY_BUF_SIZE - ldata->read_tail); |
1da177e4 | 1706 | n = min(*nr, n); |
98001214 | 1707 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 | 1708 | if (n) { |
ba2e68ac | 1709 | retval = copy_to_user(*b, &ldata->read_buf[ldata->read_tail], n); |
1da177e4 | 1710 | n -= retval; |
3fa10cc8 | 1711 | is_eof = n == 1 && |
ba2e68ac JS |
1712 | ldata->read_buf[ldata->read_tail] == EOF_CHAR(tty); |
1713 | tty_audit_add_data(tty, &ldata->read_buf[ldata->read_tail], n, | |
53c5ee2c | 1714 | ldata->icanon); |
98001214 | 1715 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac JS |
1716 | ldata->read_tail = (ldata->read_tail + n) & (N_TTY_BUF_SIZE-1); |
1717 | ldata->read_cnt -= n; | |
26df6d13 | 1718 | /* Turn single EOF into zero-length read */ |
ba2e68ac | 1719 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !ldata->read_cnt) |
3fa10cc8 | 1720 | n = 0; |
98001214 | 1721 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1722 | *b += n; |
1723 | *nr -= n; | |
1724 | } | |
1725 | return retval; | |
1726 | } | |
1727 | ||
cc4191dc | 1728 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1729 | size_t, loff_t *); |
1da177e4 LT |
1730 | |
1731 | /** | |
1732 | * job_control - check job control | |
1733 | * @tty: tty | |
1734 | * @file: file handle | |
1735 | * | |
1736 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1737 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1738 | * error code if action should be taken. |
04f378b1 | 1739 | * |
01a5e440 PH |
1740 | * Locking: redirected write test is safe |
1741 | * current->signal->tty check is safe | |
1742 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 1743 | */ |
4edf1827 | 1744 | |
1da177e4 LT |
1745 | static int job_control(struct tty_struct *tty, struct file *file) |
1746 | { | |
1747 | /* Job control check -- must be done at start and after | |
1748 | every sleep (POSIX.1 7.1.1.4). */ | |
1749 | /* NOTE: not yet done after every sleep pending a thorough | |
1750 | check of the logic of this change. -- jlc */ | |
1751 | /* don't stop on /dev/console */ | |
01a5e440 PH |
1752 | if (file->f_op->write == redirected_tty_write || |
1753 | current->signal->tty != tty) | |
1754 | return 0; | |
1755 | ||
1756 | spin_lock_irq(&tty->ctrl_lock); | |
1757 | if (!tty->pgrp) | |
1758 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
1759 | else if (task_pgrp(current) != tty->pgrp) { | |
1760 | spin_unlock_irq(&tty->ctrl_lock); | |
1761 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
1762 | return -EIO; | |
1763 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
1764 | set_thread_flag(TIF_SIGPENDING); | |
1765 | return -ERESTARTSYS; | |
1da177e4 | 1766 | } |
01a5e440 | 1767 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
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 | */ | |
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)) | |
1982 | tty->minimum_to_wake = minimum; | |
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 | } | |
2048 | if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { | |
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 LT |
2113 | { |
2114 | unsigned int mask = 0; | |
2115 | ||
2116 | poll_wait(file, &tty->read_wait, wait); | |
2117 | poll_wait(file, &tty->write_wait, wait); | |
2118 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2119 | mask |= POLLIN | POLLRDNORM; | |
2120 | if (tty->packet && tty->link->ctrl_status) | |
2121 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2122 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2123 | mask |= POLLHUP; | |
2124 | if (tty_hung_up_p(file)) | |
2125 | mask |= POLLHUP; | |
2126 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2127 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
2128 | tty->minimum_to_wake = MIN_CHAR(tty); | |
2129 | else | |
2130 | tty->minimum_to_wake = 1; | |
2131 | } | |
f34d7a5b AC |
2132 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2133 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2134 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2135 | mask |= POLLOUT | POLLWRNORM; |
2136 | return mask; | |
2137 | } | |
2138 | ||
57c94121 | 2139 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 AC |
2140 | { |
2141 | int nr, head, tail; | |
2142 | ||
ba2e68ac | 2143 | if (!ldata->canon_data) |
47afa7a5 | 2144 | return 0; |
ba2e68ac JS |
2145 | head = ldata->canon_head; |
2146 | tail = ldata->read_tail; | |
47afa7a5 AC |
2147 | nr = (head - tail) & (N_TTY_BUF_SIZE-1); |
2148 | /* Skip EOF-chars.. */ | |
2149 | while (head != tail) { | |
3fe780b3 | 2150 | if (test_bit(tail, ldata->read_flags) && |
ba2e68ac | 2151 | ldata->read_buf[tail] == __DISABLED_CHAR) |
47afa7a5 AC |
2152 | nr--; |
2153 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
2154 | } | |
2155 | return nr; | |
2156 | } | |
2157 | ||
2158 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2159 | unsigned int cmd, unsigned long arg) | |
2160 | { | |
ba2e68ac | 2161 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2162 | int retval; |
2163 | ||
2164 | switch (cmd) { | |
2165 | case TIOCOUTQ: | |
2166 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2167 | case TIOCINQ: | |
17b82060 | 2168 | /* FIXME: Locking */ |
ba2e68ac | 2169 | retval = ldata->read_cnt; |
47afa7a5 | 2170 | if (L_ICANON(tty)) |
57c94121 | 2171 | retval = inq_canon(ldata); |
47afa7a5 AC |
2172 | return put_user(retval, (unsigned int __user *) arg); |
2173 | default: | |
2174 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2175 | } | |
2176 | } | |
2177 | ||
a352def2 | 2178 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2179 | .magic = TTY_LDISC_MAGIC, |
2180 | .name = "n_tty", | |
2181 | .open = n_tty_open, | |
2182 | .close = n_tty_close, | |
2183 | .flush_buffer = n_tty_flush_buffer, | |
2184 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2185 | .read = n_tty_read, |
2186 | .write = n_tty_write, | |
e10cc1df PF |
2187 | .ioctl = n_tty_ioctl, |
2188 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2189 | .poll = n_tty_poll, |
e10cc1df PF |
2190 | .receive_buf = n_tty_receive_buf, |
2191 | .write_wakeup = n_tty_write_wakeup | |
1da177e4 | 2192 | }; |
572b9adb RG |
2193 | |
2194 | /** | |
2195 | * n_tty_inherit_ops - inherit N_TTY methods | |
2196 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2197 | * | |
593fb1ae | 2198 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2199 | * methods. |
2200 | */ | |
2201 | ||
2202 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2203 | { | |
2204 | *ops = tty_ldisc_N_TTY; | |
2205 | ops->owner = NULL; | |
2206 | ops->refcount = ops->flags = 0; | |
2207 | } | |
2208 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |