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 | ||
32f13521 PH |
77 | #undef N_TTY_TRACE |
78 | #ifdef N_TTY_TRACE | |
79 | # define n_tty_trace(f, args...) trace_printk(f, ##args) | |
80 | #else | |
81 | # define n_tty_trace(f, args...) | |
82 | #endif | |
83 | ||
70ece7a7 | 84 | struct n_tty_data { |
53c5ee2c JS |
85 | unsigned int column; |
86 | unsigned long overrun_time; | |
87 | int num_overrun; | |
88 | ||
24a89d1c PH |
89 | /* non-atomic */ |
90 | bool no_room; | |
91 | ||
53c5ee2c JS |
92 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
93 | unsigned char echo_overrun:1; | |
3fe780b3 JS |
94 | |
95 | DECLARE_BITMAP(process_char_map, 256); | |
96 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); | |
ba2e68ac JS |
97 | |
98 | char *read_buf; | |
99 | int read_head; | |
100 | int read_tail; | |
101 | int read_cnt; | |
f6c8dbe6 | 102 | int minimum_to_wake; |
ba2e68ac JS |
103 | |
104 | unsigned char *echo_buf; | |
105 | unsigned int echo_pos; | |
106 | unsigned int echo_cnt; | |
107 | ||
108 | int canon_data; | |
109 | unsigned long canon_head; | |
110 | unsigned int canon_column; | |
bddc7152 JS |
111 | |
112 | struct mutex atomic_read_lock; | |
113 | struct mutex output_lock; | |
114 | struct mutex echo_lock; | |
98001214 | 115 | raw_spinlock_t read_lock; |
70ece7a7 JS |
116 | }; |
117 | ||
522ed776 MT |
118 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
119 | unsigned char __user *ptr) | |
120 | { | |
53c5ee2c JS |
121 | struct n_tty_data *ldata = tty->disc_data; |
122 | ||
123 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
124 | return put_user(x, ptr); |
125 | } | |
126 | ||
24a89d1c | 127 | static int receive_room(struct tty_struct *tty) |
55db4c64 | 128 | { |
53c5ee2c | 129 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 130 | int left; |
55db4c64 | 131 | |
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 | 148 | |
24a89d1c | 149 | return left; |
7879a9f9 PH |
150 | } |
151 | ||
24a89d1c PH |
152 | /** |
153 | * n_tty_set_room - receive space | |
154 | * @tty: terminal | |
155 | * | |
156 | * Re-schedules the flip buffer work if space just became available. | |
157 | * | |
158 | * Locks: Concurrent update is protected with read_lock | |
159 | */ | |
160 | ||
7879a9f9 PH |
161 | static void n_tty_set_room(struct tty_struct *tty) |
162 | { | |
24a89d1c PH |
163 | struct n_tty_data *ldata = tty->disc_data; |
164 | ||
55db4c64 | 165 | /* Did this open up the receive buffer? We may need to flip */ |
24a89d1c PH |
166 | if (unlikely(ldata->no_room) && receive_room(tty)) { |
167 | ldata->no_room = 0; | |
168 | ||
ecbbfd44 | 169 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 170 | "scheduling with invalid itty\n"); |
21622939 PH |
171 | /* see if ldisc has been killed - if so, this means that |
172 | * even though the ldisc has been halted and ->buf.work | |
173 | * cancelled, ->buf.work is about to be rescheduled | |
174 | */ | |
175 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
176 | "scheduling buffer work for halted ldisc\n"); | |
ecbbfd44 JS |
177 | schedule_work(&tty->port->buf.work); |
178 | } | |
55db4c64 LT |
179 | } |
180 | ||
57c94121 | 181 | static void put_tty_queue_nolock(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 182 | { |
ba2e68ac JS |
183 | if (ldata->read_cnt < N_TTY_BUF_SIZE) { |
184 | ldata->read_buf[ldata->read_head] = c; | |
185 | ldata->read_head = (ldata->read_head + 1) & (N_TTY_BUF_SIZE-1); | |
186 | ldata->read_cnt++; | |
1da177e4 LT |
187 | } |
188 | } | |
189 | ||
17b82060 AC |
190 | /** |
191 | * put_tty_queue - add character to tty | |
192 | * @c: character | |
57c94121 | 193 | * @ldata: n_tty data |
17b82060 AC |
194 | * |
195 | * Add a character to the tty read_buf queue. This is done under the | |
196 | * read_lock to serialize character addition and also to protect us | |
197 | * against parallel reads or flushes | |
198 | */ | |
199 | ||
57c94121 | 200 | static void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 LT |
201 | { |
202 | unsigned long flags; | |
203 | /* | |
204 | * The problem of stomping on the buffers ends here. | |
205 | * Why didn't anyone see this one coming? --AJK | |
206 | */ | |
98001214 | 207 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
57c94121 | 208 | put_tty_queue_nolock(c, ldata); |
98001214 | 209 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
210 | } |
211 | ||
1da177e4 LT |
212 | /** |
213 | * reset_buffer_flags - reset buffer state | |
214 | * @tty: terminal to reset | |
215 | * | |
25518c68 PH |
216 | * Reset the read buffer counters and clear the flags. |
217 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 AC |
218 | * |
219 | * Locking: tty_read_lock for read fields. | |
1da177e4 | 220 | */ |
a88a69c9 | 221 | |
b66f4fa5 | 222 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 LT |
223 | { |
224 | unsigned long flags; | |
225 | ||
98001214 | 226 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 227 | ldata->read_head = ldata->read_tail = ldata->read_cnt = 0; |
98001214 | 228 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
a88a69c9 | 229 | |
bddc7152 | 230 | mutex_lock(&ldata->echo_lock); |
ba2e68ac | 231 | ldata->echo_pos = ldata->echo_cnt = ldata->echo_overrun = 0; |
bddc7152 | 232 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 | 233 | |
ba2e68ac | 234 | ldata->canon_head = ldata->canon_data = ldata->erasing = 0; |
3fe780b3 | 235 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
1da177e4 LT |
236 | } |
237 | ||
a30737ab PH |
238 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
239 | { | |
240 | unsigned long flags; | |
241 | ||
242 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
243 | if (tty->link->packet) { | |
244 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
245 | wake_up_interruptible(&tty->link->read_wait); | |
246 | } | |
247 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
248 | } | |
249 | ||
1da177e4 LT |
250 | /** |
251 | * n_tty_flush_buffer - clean input queue | |
252 | * @tty: terminal device | |
253 | * | |
25518c68 PH |
254 | * Flush the input buffer. Called when the tty layer wants the |
255 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
256 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 257 | * |
17b82060 | 258 | * Locking: ctrl_lock, read_lock. |
1da177e4 | 259 | */ |
4edf1827 AC |
260 | |
261 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 262 | { |
b66f4fa5 PH |
263 | reset_buffer_flags(tty->disc_data); |
264 | n_tty_set_room(tty); | |
4edf1827 | 265 | |
a30737ab PH |
266 | if (tty->link) |
267 | n_tty_packet_mode_flush(tty); | |
1da177e4 LT |
268 | } |
269 | ||
270 | /** | |
271 | * n_tty_chars_in_buffer - report available bytes | |
272 | * @tty: tty device | |
273 | * | |
274 | * Report the number of characters buffered to be delivered to user | |
4edf1827 | 275 | * at this instant in time. |
17b82060 AC |
276 | * |
277 | * Locking: read_lock | |
1da177e4 | 278 | */ |
4edf1827 | 279 | |
1da177e4 LT |
280 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
281 | { | |
53c5ee2c | 282 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
283 | unsigned long flags; |
284 | ssize_t n = 0; | |
285 | ||
98001214 | 286 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
53c5ee2c | 287 | if (!ldata->icanon) { |
ba2e68ac JS |
288 | n = ldata->read_cnt; |
289 | } else if (ldata->canon_data) { | |
290 | n = (ldata->canon_head > ldata->read_tail) ? | |
291 | ldata->canon_head - ldata->read_tail : | |
292 | ldata->canon_head + (N_TTY_BUF_SIZE - ldata->read_tail); | |
1da177e4 | 293 | } |
98001214 | 294 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
295 | return n; |
296 | } | |
297 | ||
298 | /** | |
299 | * is_utf8_continuation - utf8 multibyte check | |
300 | * @c: byte to check | |
301 | * | |
302 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
303 | * character. We use this to correctly compute the on screen size | |
304 | * of the character when printing | |
305 | */ | |
4edf1827 | 306 | |
1da177e4 LT |
307 | static inline int is_utf8_continuation(unsigned char c) |
308 | { | |
309 | return (c & 0xc0) == 0x80; | |
310 | } | |
311 | ||
312 | /** | |
313 | * is_continuation - multibyte check | |
314 | * @c: byte to check | |
315 | * | |
316 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
317 | * character and the terminal is in unicode mode. | |
318 | */ | |
4edf1827 | 319 | |
1da177e4 LT |
320 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
321 | { | |
322 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
323 | } | |
324 | ||
325 | /** | |
a88a69c9 | 326 | * do_output_char - output one character |
1da177e4 LT |
327 | * @c: character (or partial unicode symbol) |
328 | * @tty: terminal device | |
a88a69c9 | 329 | * @space: space available in tty driver write buffer |
1da177e4 | 330 | * |
a88a69c9 JP |
331 | * This is a helper function that handles one output character |
332 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
333 | * doing OPOST processing and putting the results in the |
334 | * tty driver's write buffer. | |
a88a69c9 JP |
335 | * |
336 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
337 | * and NLDLY. They simply aren't relevant in the world today. | |
338 | * If you ever need them, add them here. | |
1da177e4 | 339 | * |
a88a69c9 JP |
340 | * Returns the number of bytes of buffer space used or -1 if |
341 | * no space left. | |
342 | * | |
343 | * Locking: should be called under the output_lock to protect | |
344 | * the column state and space left in the buffer | |
1da177e4 | 345 | */ |
4edf1827 | 346 | |
a88a69c9 | 347 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 348 | { |
53c5ee2c | 349 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 350 | int spaces; |
1da177e4 | 351 | |
1da177e4 LT |
352 | if (!space) |
353 | return -1; | |
300a6204 | 354 | |
a88a69c9 JP |
355 | switch (c) { |
356 | case '\n': | |
357 | if (O_ONLRET(tty)) | |
53c5ee2c | 358 | ldata->column = 0; |
a88a69c9 JP |
359 | if (O_ONLCR(tty)) { |
360 | if (space < 2) | |
361 | return -1; | |
ba2e68ac | 362 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 363 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
364 | return 2; |
365 | } | |
ba2e68ac | 366 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
367 | break; |
368 | case '\r': | |
53c5ee2c | 369 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
370 | return 0; |
371 | if (O_OCRNL(tty)) { | |
372 | c = '\n'; | |
373 | if (O_ONLRET(tty)) | |
ba2e68ac | 374 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 375 | break; |
a88a69c9 | 376 | } |
ba2e68ac | 377 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
378 | break; |
379 | case '\t': | |
53c5ee2c | 380 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
381 | if (O_TABDLY(tty) == XTABS) { |
382 | if (space < spaces) | |
383 | return -1; | |
53c5ee2c | 384 | ldata->column += spaces; |
a88a69c9 JP |
385 | tty->ops->write(tty, " ", spaces); |
386 | return spaces; | |
1da177e4 | 387 | } |
53c5ee2c | 388 | ldata->column += spaces; |
a88a69c9 JP |
389 | break; |
390 | case '\b': | |
53c5ee2c JS |
391 | if (ldata->column > 0) |
392 | ldata->column--; | |
a88a69c9 JP |
393 | break; |
394 | default: | |
a59c0d6f JP |
395 | if (!iscntrl(c)) { |
396 | if (O_OLCUC(tty)) | |
397 | c = toupper(c); | |
398 | if (!is_continuation(c, tty)) | |
53c5ee2c | 399 | ldata->column++; |
a59c0d6f | 400 | } |
a88a69c9 | 401 | break; |
1da177e4 | 402 | } |
a88a69c9 | 403 | |
f34d7a5b | 404 | tty_put_char(tty, c); |
a88a69c9 JP |
405 | return 1; |
406 | } | |
407 | ||
408 | /** | |
409 | * process_output - output post processor | |
410 | * @c: character (or partial unicode symbol) | |
411 | * @tty: terminal device | |
412 | * | |
ee5aa7b8 JP |
413 | * Output one character with OPOST processing. |
414 | * Returns -1 when the output device is full and the character | |
415 | * must be retried. | |
a88a69c9 JP |
416 | * |
417 | * Locking: output_lock to protect column state and space left | |
418 | * (also, this is called from n_tty_write under the | |
419 | * tty layer write lock) | |
420 | */ | |
421 | ||
422 | static int process_output(unsigned char c, struct tty_struct *tty) | |
423 | { | |
bddc7152 | 424 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
425 | int space, retval; |
426 | ||
bddc7152 | 427 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
428 | |
429 | space = tty_write_room(tty); | |
430 | retval = do_output_char(c, tty, space); | |
431 | ||
bddc7152 | 432 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
433 | if (retval < 0) |
434 | return -1; | |
435 | else | |
436 | return 0; | |
1da177e4 LT |
437 | } |
438 | ||
439 | /** | |
a88a69c9 | 440 | * process_output_block - block post processor |
1da177e4 | 441 | * @tty: terminal device |
ee5aa7b8 JP |
442 | * @buf: character buffer |
443 | * @nr: number of bytes to output | |
444 | * | |
445 | * Output a block of characters with OPOST processing. | |
446 | * Returns the number of characters output. | |
1da177e4 LT |
447 | * |
448 | * This path is used to speed up block console writes, among other | |
449 | * things when processing blocks of output data. It handles only | |
450 | * the simple cases normally found and helps to generate blocks of | |
451 | * symbols for the console driver and thus improve performance. | |
452 | * | |
a88a69c9 JP |
453 | * Locking: output_lock to protect column state and space left |
454 | * (also, this is called from n_tty_write under the | |
455 | * tty layer write lock) | |
1da177e4 | 456 | */ |
4edf1827 | 457 | |
a88a69c9 JP |
458 | static ssize_t process_output_block(struct tty_struct *tty, |
459 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 460 | { |
53c5ee2c | 461 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 462 | int space; |
bbd20759 | 463 | int i; |
1da177e4 LT |
464 | const unsigned char *cp; |
465 | ||
bddc7152 | 466 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 467 | |
f34d7a5b | 468 | space = tty_write_room(tty); |
300a6204 | 469 | if (!space) { |
bddc7152 | 470 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 471 | return 0; |
a88a69c9 | 472 | } |
1da177e4 LT |
473 | if (nr > space) |
474 | nr = space; | |
475 | ||
476 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
477 | unsigned char c = *cp; |
478 | ||
479 | switch (c) { | |
1da177e4 LT |
480 | case '\n': |
481 | if (O_ONLRET(tty)) | |
53c5ee2c | 482 | ldata->column = 0; |
1da177e4 LT |
483 | if (O_ONLCR(tty)) |
484 | goto break_out; | |
ba2e68ac | 485 | ldata->canon_column = ldata->column; |
1da177e4 LT |
486 | break; |
487 | case '\r': | |
53c5ee2c | 488 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
489 | goto break_out; |
490 | if (O_OCRNL(tty)) | |
491 | goto break_out; | |
ba2e68ac | 492 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
493 | break; |
494 | case '\t': | |
495 | goto break_out; | |
496 | case '\b': | |
53c5ee2c JS |
497 | if (ldata->column > 0) |
498 | ldata->column--; | |
1da177e4 LT |
499 | break; |
500 | default: | |
a59c0d6f JP |
501 | if (!iscntrl(c)) { |
502 | if (O_OLCUC(tty)) | |
503 | goto break_out; | |
504 | if (!is_continuation(c, tty)) | |
53c5ee2c | 505 | ldata->column++; |
a59c0d6f | 506 | } |
1da177e4 LT |
507 | break; |
508 | } | |
509 | } | |
510 | break_out: | |
f34d7a5b | 511 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 512 | |
bddc7152 | 513 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
514 | return i; |
515 | } | |
516 | ||
a88a69c9 JP |
517 | /** |
518 | * process_echoes - write pending echo characters | |
519 | * @tty: terminal device | |
520 | * | |
521 | * Write previously buffered echo (and other ldisc-generated) | |
522 | * characters to the tty. | |
523 | * | |
524 | * Characters generated by the ldisc (including echoes) need to | |
525 | * be buffered because the driver's write buffer can fill during | |
526 | * heavy program output. Echoing straight to the driver will | |
527 | * often fail under these conditions, causing lost characters and | |
528 | * resulting mismatches of ldisc state information. | |
529 | * | |
530 | * Since the ldisc state must represent the characters actually sent | |
531 | * to the driver at the time of the write, operations like certain | |
532 | * changes in column state are also saved in the buffer and executed | |
533 | * here. | |
534 | * | |
535 | * A circular fifo buffer is used so that the most recent characters | |
536 | * are prioritized. Also, when control characters are echoed with a | |
537 | * prefixed "^", the pair is treated atomically and thus not separated. | |
538 | * | |
539 | * Locking: output_lock to protect column state and space left, | |
540 | * echo_lock to protect the echo buffer | |
541 | */ | |
542 | ||
543 | static void process_echoes(struct tty_struct *tty) | |
544 | { | |
53c5ee2c | 545 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
546 | int space, nr; |
547 | unsigned char c; | |
548 | unsigned char *cp, *buf_end; | |
549 | ||
ba2e68ac | 550 | if (!ldata->echo_cnt) |
a88a69c9 JP |
551 | return; |
552 | ||
bddc7152 JS |
553 | mutex_lock(&ldata->output_lock); |
554 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
555 | |
556 | space = tty_write_room(tty); | |
557 | ||
ba2e68ac JS |
558 | buf_end = ldata->echo_buf + N_TTY_BUF_SIZE; |
559 | cp = ldata->echo_buf + ldata->echo_pos; | |
560 | nr = ldata->echo_cnt; | |
a88a69c9 JP |
561 | while (nr > 0) { |
562 | c = *cp; | |
563 | if (c == ECHO_OP_START) { | |
564 | unsigned char op; | |
565 | unsigned char *opp; | |
566 | int no_space_left = 0; | |
567 | ||
568 | /* | |
569 | * If the buffer byte is the start of a multi-byte | |
570 | * operation, get the next byte, which is either the | |
571 | * op code or a control character value. | |
572 | */ | |
573 | opp = cp + 1; | |
574 | if (opp == buf_end) | |
575 | opp -= N_TTY_BUF_SIZE; | |
576 | op = *opp; | |
300a6204 | 577 | |
a88a69c9 JP |
578 | switch (op) { |
579 | unsigned int num_chars, num_bs; | |
580 | ||
581 | case ECHO_OP_ERASE_TAB: | |
582 | if (++opp == buf_end) | |
583 | opp -= N_TTY_BUF_SIZE; | |
584 | num_chars = *opp; | |
585 | ||
586 | /* | |
587 | * Determine how many columns to go back | |
588 | * in order to erase the tab. | |
589 | * This depends on the number of columns | |
590 | * used by other characters within the tab | |
591 | * area. If this (modulo 8) count is from | |
592 | * the start of input rather than from a | |
593 | * previous tab, we offset by canon column. | |
594 | * Otherwise, tab spacing is normal. | |
595 | */ | |
596 | if (!(num_chars & 0x80)) | |
ba2e68ac | 597 | num_chars += ldata->canon_column; |
a88a69c9 JP |
598 | num_bs = 8 - (num_chars & 7); |
599 | ||
600 | if (num_bs > space) { | |
601 | no_space_left = 1; | |
602 | break; | |
603 | } | |
604 | space -= num_bs; | |
605 | while (num_bs--) { | |
606 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
607 | if (ldata->column > 0) |
608 | ldata->column--; | |
a88a69c9 JP |
609 | } |
610 | cp += 3; | |
611 | nr -= 3; | |
612 | break; | |
613 | ||
614 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 615 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
616 | cp += 2; |
617 | nr -= 2; | |
618 | break; | |
619 | ||
620 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
621 | if (ldata->column > 0) |
622 | ldata->column--; | |
a88a69c9 JP |
623 | cp += 2; |
624 | nr -= 2; | |
625 | break; | |
626 | ||
627 | case ECHO_OP_START: | |
628 | /* This is an escaped echo op start code */ | |
629 | if (!space) { | |
630 | no_space_left = 1; | |
631 | break; | |
632 | } | |
633 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 634 | ldata->column++; |
a88a69c9 JP |
635 | space--; |
636 | cp += 2; | |
637 | nr -= 2; | |
638 | break; | |
639 | ||
640 | default: | |
a88a69c9 | 641 | /* |
62b26358 JP |
642 | * If the op is not a special byte code, |
643 | * it is a ctrl char tagged to be echoed | |
644 | * as "^X" (where X is the letter | |
645 | * representing the control char). | |
646 | * Note that we must ensure there is | |
647 | * enough space for the whole ctrl pair. | |
648 | * | |
a88a69c9 | 649 | */ |
62b26358 JP |
650 | if (space < 2) { |
651 | no_space_left = 1; | |
652 | break; | |
653 | } | |
654 | tty_put_char(tty, '^'); | |
655 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 656 | ldata->column += 2; |
62b26358 | 657 | space -= 2; |
a88a69c9 JP |
658 | cp += 2; |
659 | nr -= 2; | |
660 | } | |
661 | ||
662 | if (no_space_left) | |
663 | break; | |
664 | } else { | |
582f5590 | 665 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
666 | int retval = do_output_char(c, tty, space); |
667 | if (retval < 0) | |
668 | break; | |
669 | space -= retval; | |
670 | } else { | |
671 | if (!space) | |
672 | break; | |
673 | tty_put_char(tty, c); | |
674 | space -= 1; | |
675 | } | |
a88a69c9 JP |
676 | cp += 1; |
677 | nr -= 1; | |
678 | } | |
679 | ||
680 | /* When end of circular buffer reached, wrap around */ | |
681 | if (cp >= buf_end) | |
682 | cp -= N_TTY_BUF_SIZE; | |
683 | } | |
684 | ||
685 | if (nr == 0) { | |
ba2e68ac JS |
686 | ldata->echo_pos = 0; |
687 | ldata->echo_cnt = 0; | |
53c5ee2c | 688 | ldata->echo_overrun = 0; |
a88a69c9 | 689 | } else { |
ba2e68ac JS |
690 | int num_processed = ldata->echo_cnt - nr; |
691 | ldata->echo_pos += num_processed; | |
692 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; | |
693 | ldata->echo_cnt = nr; | |
a88a69c9 | 694 | if (num_processed > 0) |
53c5ee2c | 695 | ldata->echo_overrun = 0; |
a88a69c9 JP |
696 | } |
697 | ||
bddc7152 JS |
698 | mutex_unlock(&ldata->echo_lock); |
699 | mutex_unlock(&ldata->output_lock); | |
a88a69c9 JP |
700 | |
701 | if (tty->ops->flush_chars) | |
702 | tty->ops->flush_chars(tty); | |
703 | } | |
704 | ||
705 | /** | |
706 | * add_echo_byte - add a byte to the echo buffer | |
707 | * @c: unicode byte to echo | |
57c94121 | 708 | * @ldata: n_tty data |
a88a69c9 JP |
709 | * |
710 | * Add a character or operation byte to the echo buffer. | |
711 | * | |
712 | * Should be called under the echo lock to protect the echo buffer. | |
713 | */ | |
714 | ||
57c94121 | 715 | static void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 JP |
716 | { |
717 | int new_byte_pos; | |
718 | ||
ba2e68ac | 719 | if (ldata->echo_cnt == N_TTY_BUF_SIZE) { |
a88a69c9 | 720 | /* Circular buffer is already at capacity */ |
ba2e68ac | 721 | new_byte_pos = ldata->echo_pos; |
a88a69c9 JP |
722 | |
723 | /* | |
724 | * Since the buffer start position needs to be advanced, | |
725 | * be sure to step by a whole operation byte group. | |
726 | */ | |
ba2e68ac JS |
727 | if (ldata->echo_buf[ldata->echo_pos] == ECHO_OP_START) { |
728 | if (ldata->echo_buf[(ldata->echo_pos + 1) & | |
a88a69c9 JP |
729 | (N_TTY_BUF_SIZE - 1)] == |
730 | ECHO_OP_ERASE_TAB) { | |
ba2e68ac JS |
731 | ldata->echo_pos += 3; |
732 | ldata->echo_cnt -= 2; | |
a88a69c9 | 733 | } else { |
ba2e68ac JS |
734 | ldata->echo_pos += 2; |
735 | ldata->echo_cnt -= 1; | |
a88a69c9 JP |
736 | } |
737 | } else { | |
ba2e68ac | 738 | ldata->echo_pos++; |
a88a69c9 | 739 | } |
ba2e68ac | 740 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; |
a88a69c9 | 741 | |
53c5ee2c | 742 | ldata->echo_overrun = 1; |
a88a69c9 | 743 | } else { |
ba2e68ac | 744 | new_byte_pos = ldata->echo_pos + ldata->echo_cnt; |
a88a69c9 | 745 | new_byte_pos &= N_TTY_BUF_SIZE - 1; |
ba2e68ac | 746 | ldata->echo_cnt++; |
a88a69c9 JP |
747 | } |
748 | ||
ba2e68ac | 749 | ldata->echo_buf[new_byte_pos] = c; |
a88a69c9 JP |
750 | } |
751 | ||
752 | /** | |
753 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 754 | * @ldata: n_tty data |
a88a69c9 JP |
755 | * |
756 | * Add an operation to the echo buffer to move back one column. | |
757 | * | |
758 | * Locking: echo_lock to protect the echo buffer | |
759 | */ | |
760 | ||
57c94121 | 761 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 762 | { |
bddc7152 | 763 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
764 | add_echo_byte(ECHO_OP_START, ldata); |
765 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
bddc7152 | 766 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
767 | } |
768 | ||
769 | /** | |
770 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 771 | * @ldata: n_tty data |
a88a69c9 JP |
772 | * |
773 | * Add an operation to the echo buffer to set the canon column | |
774 | * to the current column. | |
775 | * | |
776 | * Locking: echo_lock to protect the echo buffer | |
777 | */ | |
778 | ||
57c94121 | 779 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 780 | { |
bddc7152 | 781 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
782 | add_echo_byte(ECHO_OP_START, ldata); |
783 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
bddc7152 | 784 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
785 | } |
786 | ||
787 | /** | |
788 | * echo_erase_tab - add operation to erase a tab | |
789 | * @num_chars: number of character columns already used | |
790 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 791 | * @ldata: n_tty data |
a88a69c9 JP |
792 | * |
793 | * Add an operation to the echo buffer to erase a tab. | |
794 | * | |
795 | * Called by the eraser function, which knows how many character | |
796 | * columns have been used since either a previous tab or the start | |
797 | * of input. This information will be used later, along with | |
798 | * canon column (if applicable), to go back the correct number | |
799 | * of columns. | |
800 | * | |
801 | * Locking: echo_lock to protect the echo buffer | |
802 | */ | |
803 | ||
804 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 805 | struct n_tty_data *ldata) |
a88a69c9 | 806 | { |
bddc7152 | 807 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 808 | |
57c94121 JS |
809 | add_echo_byte(ECHO_OP_START, ldata); |
810 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
811 | |
812 | /* We only need to know this modulo 8 (tab spacing) */ | |
813 | num_chars &= 7; | |
814 | ||
815 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
816 | if (after_tab) | |
817 | num_chars |= 0x80; | |
300a6204 | 818 | |
57c94121 | 819 | add_echo_byte(num_chars, ldata); |
a88a69c9 | 820 | |
bddc7152 | 821 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
822 | } |
823 | ||
824 | /** | |
825 | * echo_char_raw - echo a character raw | |
826 | * @c: unicode byte to echo | |
827 | * @tty: terminal device | |
828 | * | |
829 | * Echo user input back onto the screen. This must be called only when | |
830 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
831 | * | |
832 | * This variant does not treat control characters specially. | |
833 | * | |
834 | * Locking: echo_lock to protect the echo buffer | |
835 | */ | |
836 | ||
57c94121 | 837 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 838 | { |
bddc7152 | 839 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 840 | if (c == ECHO_OP_START) { |
57c94121 JS |
841 | add_echo_byte(ECHO_OP_START, ldata); |
842 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 843 | } else { |
57c94121 | 844 | add_echo_byte(c, ldata); |
a88a69c9 | 845 | } |
bddc7152 | 846 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 | 847 | } |
1da177e4 | 848 | |
1da177e4 | 849 | /** |
a88a69c9 | 850 | * echo_char - echo a character |
1da177e4 LT |
851 | * @c: unicode byte to echo |
852 | * @tty: terminal device | |
853 | * | |
4edf1827 | 854 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 855 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 856 | * |
62b26358 JP |
857 | * This variant tags control characters to be echoed as "^X" |
858 | * (where X is the letter representing the control char). | |
a88a69c9 JP |
859 | * |
860 | * Locking: echo_lock to protect the echo buffer | |
1da177e4 LT |
861 | */ |
862 | ||
863 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
864 | { | |
bddc7152 JS |
865 | struct n_tty_data *ldata = tty->disc_data; |
866 | ||
867 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
868 | |
869 | if (c == ECHO_OP_START) { | |
57c94121 JS |
870 | add_echo_byte(ECHO_OP_START, ldata); |
871 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 872 | } else { |
62b26358 | 873 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
874 | add_echo_byte(ECHO_OP_START, ldata); |
875 | add_echo_byte(c, ldata); | |
a88a69c9 JP |
876 | } |
877 | ||
bddc7152 | 878 | mutex_unlock(&ldata->echo_lock); |
1da177e4 LT |
879 | } |
880 | ||
17b82060 | 881 | /** |
a88a69c9 | 882 | * finish_erasing - complete erase |
57c94121 | 883 | * @ldata: n_tty data |
17b82060 | 884 | */ |
a88a69c9 | 885 | |
57c94121 | 886 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 887 | { |
53c5ee2c | 888 | if (ldata->erasing) { |
57c94121 | 889 | echo_char_raw('/', ldata); |
53c5ee2c | 890 | ldata->erasing = 0; |
1da177e4 LT |
891 | } |
892 | } | |
893 | ||
894 | /** | |
895 | * eraser - handle erase function | |
896 | * @c: character input | |
897 | * @tty: terminal device | |
898 | * | |
3a4fa0a2 | 899 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
900 | * present in the stream from the driver layer. Handles the complexities |
901 | * of UTF-8 multibyte symbols. | |
17b82060 | 902 | * |
a88a69c9 | 903 | * Locking: read_lock for tty buffers |
1da177e4 | 904 | */ |
4edf1827 | 905 | |
1da177e4 LT |
906 | static void eraser(unsigned char c, struct tty_struct *tty) |
907 | { | |
53c5ee2c | 908 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
909 | enum { ERASE, WERASE, KILL } kill_type; |
910 | int head, seen_alnums, cnt; | |
911 | unsigned long flags; | |
912 | ||
17b82060 | 913 | /* FIXME: locking needed ? */ |
ba2e68ac | 914 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 915 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
916 | return; |
917 | } | |
918 | if (c == ERASE_CHAR(tty)) | |
919 | kill_type = ERASE; | |
920 | else if (c == WERASE_CHAR(tty)) | |
921 | kill_type = WERASE; | |
922 | else { | |
923 | if (!L_ECHO(tty)) { | |
98001214 | 924 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 925 | ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) & |
1da177e4 | 926 | (N_TTY_BUF_SIZE - 1)); |
ba2e68ac | 927 | ldata->read_head = ldata->canon_head; |
98001214 | 928 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
929 | return; |
930 | } | |
931 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
98001214 | 932 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 933 | ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) & |
1da177e4 | 934 | (N_TTY_BUF_SIZE - 1)); |
ba2e68ac | 935 | ldata->read_head = ldata->canon_head; |
98001214 | 936 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
57c94121 | 937 | finish_erasing(ldata); |
1da177e4 LT |
938 | echo_char(KILL_CHAR(tty), tty); |
939 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
940 | if (L_ECHOK(tty)) | |
57c94121 | 941 | echo_char_raw('\n', ldata); |
1da177e4 LT |
942 | return; |
943 | } | |
944 | kill_type = KILL; | |
945 | } | |
946 | ||
947 | seen_alnums = 0; | |
17b82060 | 948 | /* FIXME: Locking ?? */ |
ba2e68ac JS |
949 | while (ldata->read_head != ldata->canon_head) { |
950 | head = ldata->read_head; | |
1da177e4 LT |
951 | |
952 | /* erase a single possibly multibyte character */ | |
953 | do { | |
954 | head = (head - 1) & (N_TTY_BUF_SIZE-1); | |
ba2e68ac JS |
955 | c = ldata->read_buf[head]; |
956 | } while (is_continuation(c, tty) && head != ldata->canon_head); | |
1da177e4 LT |
957 | |
958 | /* do not partially erase */ | |
959 | if (is_continuation(c, tty)) | |
960 | break; | |
961 | ||
962 | if (kill_type == WERASE) { | |
963 | /* Equivalent to BSD's ALTWERASE. */ | |
964 | if (isalnum(c) || c == '_') | |
965 | seen_alnums++; | |
966 | else if (seen_alnums) | |
967 | break; | |
968 | } | |
ba2e68ac | 969 | cnt = (ldata->read_head - head) & (N_TTY_BUF_SIZE-1); |
98001214 | 970 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac JS |
971 | ldata->read_head = head; |
972 | ldata->read_cnt -= cnt; | |
98001214 | 973 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
974 | if (L_ECHO(tty)) { |
975 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 976 | if (!ldata->erasing) { |
57c94121 | 977 | echo_char_raw('\\', ldata); |
53c5ee2c | 978 | ldata->erasing = 1; |
1da177e4 LT |
979 | } |
980 | /* if cnt > 1, output a multi-byte character */ | |
981 | echo_char(c, tty); | |
982 | while (--cnt > 0) { | |
983 | head = (head+1) & (N_TTY_BUF_SIZE-1); | |
57c94121 JS |
984 | echo_char_raw(ldata->read_buf[head], |
985 | ldata); | |
986 | echo_move_back_col(ldata); | |
1da177e4 LT |
987 | } |
988 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
989 | echo_char(ERASE_CHAR(tty), tty); | |
990 | } else if (c == '\t') { | |
a88a69c9 JP |
991 | unsigned int num_chars = 0; |
992 | int after_tab = 0; | |
ba2e68ac | 993 | unsigned long tail = ldata->read_head; |
a88a69c9 JP |
994 | |
995 | /* | |
996 | * Count the columns used for characters | |
997 | * since the start of input or after a | |
998 | * previous tab. | |
999 | * This info is used to go back the correct | |
1000 | * number of columns. | |
1001 | */ | |
ba2e68ac | 1002 | while (tail != ldata->canon_head) { |
a88a69c9 | 1003 | tail = (tail-1) & (N_TTY_BUF_SIZE-1); |
ba2e68ac | 1004 | c = ldata->read_buf[tail]; |
a88a69c9 JP |
1005 | if (c == '\t') { |
1006 | after_tab = 1; | |
1007 | break; | |
300a6204 | 1008 | } else if (iscntrl(c)) { |
1da177e4 | 1009 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1010 | num_chars += 2; |
1011 | } else if (!is_continuation(c, tty)) { | |
1012 | num_chars++; | |
1013 | } | |
1da177e4 | 1014 | } |
57c94121 | 1015 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1016 | } else { |
1017 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1018 | echo_char_raw('\b', ldata); |
1019 | echo_char_raw(' ', ldata); | |
1020 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1021 | } |
1022 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1023 | echo_char_raw('\b', ldata); |
1024 | echo_char_raw(' ', ldata); | |
1025 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1026 | } |
1027 | } | |
1028 | } | |
1029 | if (kill_type == ERASE) | |
1030 | break; | |
1031 | } | |
ba2e68ac | 1032 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1033 | finish_erasing(ldata); |
1da177e4 LT |
1034 | } |
1035 | ||
1036 | /** | |
1037 | * isig - handle the ISIG optio | |
1038 | * @sig: signal | |
1039 | * @tty: terminal | |
1da177e4 | 1040 | * |
8c985d18 PH |
1041 | * Called when a signal is being sent due to terminal input. |
1042 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1043 | * |
8c985d18 | 1044 | * Locking: ctrl_lock |
1da177e4 | 1045 | */ |
4edf1827 | 1046 | |
8c985d18 | 1047 | static inline void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1048 | { |
8c985d18 PH |
1049 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1050 | if (tty_pgrp) { | |
1051 | kill_pgrp(tty_pgrp, sig, 1); | |
1052 | put_pid(tty_pgrp); | |
1da177e4 LT |
1053 | } |
1054 | } | |
1055 | ||
1056 | /** | |
1057 | * n_tty_receive_break - handle break | |
1058 | * @tty: terminal | |
1059 | * | |
1060 | * An RS232 break event has been hit in the incoming bitstream. This | |
1061 | * can cause a variety of events depending upon the termios settings. | |
1062 | * | |
1063 | * Called from the receive_buf path so single threaded. | |
1064 | */ | |
4edf1827 | 1065 | |
1da177e4 LT |
1066 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1067 | { | |
57c94121 JS |
1068 | struct n_tty_data *ldata = tty->disc_data; |
1069 | ||
1da177e4 LT |
1070 | if (I_IGNBRK(tty)) |
1071 | return; | |
1072 | if (I_BRKINT(tty)) { | |
8c985d18 PH |
1073 | isig(SIGINT, tty); |
1074 | if (!L_NOFLSH(tty)) { | |
1075 | n_tty_flush_buffer(tty); | |
1076 | tty_driver_flush_buffer(tty); | |
1077 | } | |
1da177e4 LT |
1078 | return; |
1079 | } | |
1080 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1081 | put_tty_queue('\377', ldata); |
1082 | put_tty_queue('\0', ldata); | |
1da177e4 | 1083 | } |
57c94121 | 1084 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1085 | wake_up_interruptible(&tty->read_wait); |
1086 | } | |
1087 | ||
1088 | /** | |
1089 | * n_tty_receive_overrun - handle overrun reporting | |
1090 | * @tty: terminal | |
1091 | * | |
1092 | * Data arrived faster than we could process it. While the tty | |
1093 | * driver has flagged this the bits that were missed are gone | |
1094 | * forever. | |
1095 | * | |
1096 | * Called from the receive_buf path so single threaded. Does not | |
1097 | * need locking as num_overrun and overrun_time are function | |
1098 | * private. | |
1099 | */ | |
4edf1827 | 1100 | |
1da177e4 LT |
1101 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1102 | { | |
53c5ee2c | 1103 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1104 | char buf[64]; |
1105 | ||
53c5ee2c JS |
1106 | ldata->num_overrun++; |
1107 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1108 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1109 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1110 | tty_name(tty, buf), | |
53c5ee2c JS |
1111 | ldata->num_overrun); |
1112 | ldata->overrun_time = jiffies; | |
1113 | ldata->num_overrun = 0; | |
1da177e4 LT |
1114 | } |
1115 | } | |
1116 | ||
1117 | /** | |
1118 | * n_tty_receive_parity_error - error notifier | |
1119 | * @tty: terminal device | |
1120 | * @c: character | |
1121 | * | |
1122 | * Process a parity error and queue the right data to indicate | |
3a4fa0a2 | 1123 | * the error case if necessary. Locking as per n_tty_receive_buf. |
1da177e4 LT |
1124 | */ |
1125 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1126 | unsigned char c) | |
1127 | { | |
57c94121 JS |
1128 | struct n_tty_data *ldata = tty->disc_data; |
1129 | ||
4edf1827 | 1130 | if (I_IGNPAR(tty)) |
1da177e4 | 1131 | return; |
1da177e4 | 1132 | if (I_PARMRK(tty)) { |
57c94121 JS |
1133 | put_tty_queue('\377', ldata); |
1134 | put_tty_queue('\0', ldata); | |
1135 | put_tty_queue(c, ldata); | |
1da177e4 | 1136 | } else if (I_INPCK(tty)) |
57c94121 | 1137 | put_tty_queue('\0', ldata); |
1da177e4 | 1138 | else |
57c94121 | 1139 | put_tty_queue(c, ldata); |
1da177e4 LT |
1140 | wake_up_interruptible(&tty->read_wait); |
1141 | } | |
1142 | ||
1143 | /** | |
1144 | * n_tty_receive_char - perform processing | |
1145 | * @tty: terminal device | |
1146 | * @c: character | |
1147 | * | |
1148 | * Process an individual character of input received from the driver. | |
4edf1827 | 1149 | * This is serialized with respect to itself by the rules for the |
1da177e4 LT |
1150 | * driver above. |
1151 | */ | |
1152 | ||
1153 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1154 | { | |
53c5ee2c | 1155 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1156 | unsigned long flags; |
acc71bba | 1157 | int parmrk; |
1da177e4 | 1158 | |
53c5ee2c | 1159 | if (ldata->raw) { |
57c94121 | 1160 | put_tty_queue(c, ldata); |
1da177e4 LT |
1161 | return; |
1162 | } | |
4edf1827 | 1163 | |
1da177e4 LT |
1164 | if (I_ISTRIP(tty)) |
1165 | c &= 0x7f; | |
1166 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1167 | c = tolower(c); |
1da177e4 | 1168 | |
26df6d13 | 1169 | if (L_EXTPROC(tty)) { |
57c94121 | 1170 | put_tty_queue(c, ldata); |
26df6d13 | 1171 | return; |
1172 | } | |
1173 | ||
54d2a37e | 1174 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1175 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1176 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1177 | start_tty(tty); |
a88a69c9 JP |
1178 | process_echoes(tty); |
1179 | } | |
54d2a37e | 1180 | |
1da177e4 LT |
1181 | if (tty->closing) { |
1182 | if (I_IXON(tty)) { | |
a88a69c9 | 1183 | if (c == START_CHAR(tty)) { |
1da177e4 | 1184 | start_tty(tty); |
a88a69c9 | 1185 | process_echoes(tty); |
300a6204 | 1186 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1187 | stop_tty(tty); |
1188 | } | |
1189 | return; | |
1190 | } | |
1191 | ||
1192 | /* | |
1193 | * If the previous character was LNEXT, or we know that this | |
1194 | * character is not one of the characters that we'll have to | |
1195 | * handle specially, do shortcut processing to speed things | |
1196 | * up. | |
1197 | */ | |
3fe780b3 | 1198 | if (!test_bit(c, ldata->process_char_map) || ldata->lnext) { |
53c5ee2c | 1199 | ldata->lnext = 0; |
acc71bba | 1200 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ba2e68ac | 1201 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1202 | /* beep if no space */ |
7e94b1d9 JP |
1203 | if (L_ECHO(tty)) |
1204 | process_output('\a', tty); | |
acc71bba JP |
1205 | return; |
1206 | } | |
1207 | if (L_ECHO(tty)) { | |
57c94121 | 1208 | finish_erasing(ldata); |
1da177e4 | 1209 | /* Record the column of first canon char. */ |
ba2e68ac | 1210 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1211 | echo_set_canon_col(ldata); |
1da177e4 | 1212 | echo_char(c, tty); |
a88a69c9 | 1213 | process_echoes(tty); |
1da177e4 | 1214 | } |
acc71bba | 1215 | if (parmrk) |
57c94121 JS |
1216 | put_tty_queue(c, ldata); |
1217 | put_tty_queue(c, ldata); | |
1da177e4 LT |
1218 | return; |
1219 | } | |
4edf1827 | 1220 | |
1da177e4 LT |
1221 | if (I_IXON(tty)) { |
1222 | if (c == START_CHAR(tty)) { | |
1223 | start_tty(tty); | |
a88a69c9 | 1224 | process_echoes(tty); |
1da177e4 LT |
1225 | return; |
1226 | } | |
1227 | if (c == STOP_CHAR(tty)) { | |
1228 | stop_tty(tty); | |
1229 | return; | |
1230 | } | |
1231 | } | |
575537b3 | 1232 | |
1da177e4 LT |
1233 | if (L_ISIG(tty)) { |
1234 | int signal; | |
1235 | signal = SIGINT; | |
1236 | if (c == INTR_CHAR(tty)) | |
1237 | goto send_signal; | |
1238 | signal = SIGQUIT; | |
1239 | if (c == QUIT_CHAR(tty)) | |
1240 | goto send_signal; | |
1241 | signal = SIGTSTP; | |
1242 | if (c == SUSP_CHAR(tty)) { | |
1243 | send_signal: | |
ec5b1157 JP |
1244 | if (!L_NOFLSH(tty)) { |
1245 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1246 | tty_driver_flush_buffer(tty); |
ec5b1157 | 1247 | } |
a88a69c9 JP |
1248 | if (I_IXON(tty)) |
1249 | start_tty(tty); | |
1250 | if (L_ECHO(tty)) { | |
ec5b1157 | 1251 | echo_char(c, tty); |
a88a69c9 JP |
1252 | process_echoes(tty); |
1253 | } | |
8c985d18 | 1254 | isig(signal, tty); |
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 | |
24a89d1c PH |
1415 | static void __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 | ||
f6c8dbe6 | 1471 | if ((!ldata->icanon && (ldata->read_cnt >= ldata->minimum_to_wake)) || |
26df6d13 | 1472 | L_EXTPROC(tty)) { |
1da177e4 LT |
1473 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1474 | if (waitqueue_active(&tty->read_wait)) | |
1475 | wake_up_interruptible(&tty->read_wait); | |
1476 | } | |
1477 | ||
1478 | /* | |
1479 | * Check the remaining room for the input canonicalization | |
1480 | * mode. We don't want to throttle the driver if we're in | |
1481 | * canonical mode and don't have a newline yet! | |
1482 | */ | |
e91e52e4 PH |
1483 | while (1) { |
1484 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
24a89d1c | 1485 | if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) |
e91e52e4 PH |
1486 | break; |
1487 | if (!tty_throttle_safe(tty)) | |
1488 | break; | |
1489 | } | |
1490 | __tty_set_flow_change(tty, 0); | |
1da177e4 LT |
1491 | } |
1492 | ||
24a89d1c PH |
1493 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1494 | char *fp, int count) | |
1495 | { | |
1496 | __receive_buf(tty, cp, fp, count); | |
1497 | } | |
1498 | ||
1499 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1500 | char *fp, int count) | |
1501 | { | |
1502 | struct n_tty_data *ldata = tty->disc_data; | |
1503 | int room; | |
1504 | ||
1505 | tty->receive_room = room = receive_room(tty); | |
1506 | if (!room) | |
1507 | ldata->no_room = 1; | |
1508 | count = min(count, room); | |
1509 | if (count) | |
1510 | __receive_buf(tty, cp, fp, count); | |
1511 | ||
1512 | return count; | |
1513 | } | |
1514 | ||
1da177e4 LT |
1515 | int is_ignored(int sig) |
1516 | { | |
1517 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1518 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1519 | } |
1520 | ||
1521 | /** | |
1522 | * n_tty_set_termios - termios data changed | |
1523 | * @tty: terminal | |
1524 | * @old: previous data | |
1525 | * | |
1526 | * Called by the tty layer when the user changes termios flags so | |
1527 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1528 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1529 | * guaranteed that this function will not be re-entered or in progress |
1530 | * when the ldisc is closed. | |
17b82060 AC |
1531 | * |
1532 | * Locking: Caller holds tty->termios_mutex | |
1da177e4 | 1533 | */ |
4edf1827 AC |
1534 | |
1535 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1536 | { |
53c5ee2c | 1537 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1538 | int canon_change = 1; |
47afa7a5 AC |
1539 | |
1540 | if (old) | |
adc8d746 | 1541 | canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON; |
47afa7a5 | 1542 | if (canon_change) { |
3fe780b3 | 1543 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
ba2e68ac JS |
1544 | ldata->canon_head = ldata->read_tail; |
1545 | ldata->canon_data = 0; | |
53c5ee2c | 1546 | ldata->erasing = 0; |
47afa7a5 AC |
1547 | } |
1548 | ||
ba2e68ac | 1549 | if (canon_change && !L_ICANON(tty) && ldata->read_cnt) |
47afa7a5 | 1550 | wake_up_interruptible(&tty->read_wait); |
4edf1827 | 1551 | |
53c5ee2c | 1552 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1553 | |
1da177e4 LT |
1554 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1555 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1556 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1557 | I_PARMRK(tty)) { | |
3fe780b3 | 1558 | bitmap_zero(ldata->process_char_map, 256); |
1da177e4 LT |
1559 | |
1560 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
3fe780b3 | 1561 | set_bit('\r', ldata->process_char_map); |
1da177e4 | 1562 | if (I_INLCR(tty)) |
3fe780b3 | 1563 | set_bit('\n', ldata->process_char_map); |
1da177e4 LT |
1564 | |
1565 | if (L_ICANON(tty)) { | |
3fe780b3 JS |
1566 | set_bit(ERASE_CHAR(tty), ldata->process_char_map); |
1567 | set_bit(KILL_CHAR(tty), ldata->process_char_map); | |
1568 | set_bit(EOF_CHAR(tty), ldata->process_char_map); | |
1569 | set_bit('\n', ldata->process_char_map); | |
1570 | set_bit(EOL_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1571 | if (L_IEXTEN(tty)) { |
1572 | set_bit(WERASE_CHAR(tty), | |
3fe780b3 | 1573 | ldata->process_char_map); |
1da177e4 | 1574 | set_bit(LNEXT_CHAR(tty), |
3fe780b3 | 1575 | ldata->process_char_map); |
1da177e4 | 1576 | set_bit(EOL2_CHAR(tty), |
3fe780b3 | 1577 | ldata->process_char_map); |
1da177e4 LT |
1578 | if (L_ECHO(tty)) |
1579 | set_bit(REPRINT_CHAR(tty), | |
3fe780b3 | 1580 | ldata->process_char_map); |
1da177e4 LT |
1581 | } |
1582 | } | |
1583 | if (I_IXON(tty)) { | |
3fe780b3 JS |
1584 | set_bit(START_CHAR(tty), ldata->process_char_map); |
1585 | set_bit(STOP_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1586 | } |
1587 | if (L_ISIG(tty)) { | |
3fe780b3 JS |
1588 | set_bit(INTR_CHAR(tty), ldata->process_char_map); |
1589 | set_bit(QUIT_CHAR(tty), ldata->process_char_map); | |
1590 | set_bit(SUSP_CHAR(tty), ldata->process_char_map); | |
1da177e4 | 1591 | } |
3fe780b3 | 1592 | clear_bit(__DISABLED_CHAR, ldata->process_char_map); |
53c5ee2c JS |
1593 | ldata->raw = 0; |
1594 | ldata->real_raw = 0; | |
1da177e4 | 1595 | } else { |
53c5ee2c | 1596 | ldata->raw = 1; |
1da177e4 LT |
1597 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1598 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1599 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1600 | ldata->real_raw = 1; |
1da177e4 | 1601 | else |
53c5ee2c | 1602 | ldata->real_raw = 0; |
1da177e4 | 1603 | } |
55db4c64 | 1604 | n_tty_set_room(tty); |
dab73b4e WY |
1605 | /* |
1606 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1607 | * been stopped by STOP_CHAR(tty) before it. | |
1608 | */ | |
1609 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { | |
1610 | start_tty(tty); | |
1611 | } | |
1612 | ||
f34d7a5b AC |
1613 | /* The termios change make the tty ready for I/O */ |
1614 | wake_up_interruptible(&tty->write_wait); | |
1615 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1616 | } |
1617 | ||
1618 | /** | |
1619 | * n_tty_close - close the ldisc for this tty | |
1620 | * @tty: device | |
1621 | * | |
4edf1827 AC |
1622 | * Called from the terminal layer when this line discipline is |
1623 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1624 | * discipline change. The function will not be called while other |
1625 | * ldisc methods are in progress. | |
1626 | */ | |
4edf1827 | 1627 | |
1da177e4 LT |
1628 | static void n_tty_close(struct tty_struct *tty) |
1629 | { | |
70ece7a7 JS |
1630 | struct n_tty_data *ldata = tty->disc_data; |
1631 | ||
79901317 PH |
1632 | if (tty->link) |
1633 | n_tty_packet_mode_flush(tty); | |
1634 | ||
ba2e68ac JS |
1635 | kfree(ldata->read_buf); |
1636 | kfree(ldata->echo_buf); | |
70ece7a7 | 1637 | kfree(ldata); |
70ece7a7 | 1638 | tty->disc_data = NULL; |
1da177e4 LT |
1639 | } |
1640 | ||
1641 | /** | |
1642 | * n_tty_open - open an ldisc | |
1643 | * @tty: terminal to open | |
1644 | * | |
4edf1827 | 1645 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1646 | * terminal device. Can sleep. Called serialized so that no |
1647 | * other events will occur in parallel. No further open will occur | |
1648 | * until a close. | |
1649 | */ | |
1650 | ||
1651 | static int n_tty_open(struct tty_struct *tty) | |
1652 | { | |
70ece7a7 JS |
1653 | struct n_tty_data *ldata; |
1654 | ||
1655 | ldata = kzalloc(sizeof(*ldata), GFP_KERNEL); | |
1656 | if (!ldata) | |
1657 | goto err; | |
1658 | ||
53c5ee2c | 1659 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1660 | mutex_init(&ldata->atomic_read_lock); |
1661 | mutex_init(&ldata->output_lock); | |
1662 | mutex_init(&ldata->echo_lock); | |
98001214 | 1663 | raw_spin_lock_init(&ldata->read_lock); |
53c5ee2c | 1664 | |
a88a69c9 | 1665 | /* These are ugly. Currently a malloc failure here can panic */ |
ba2e68ac JS |
1666 | ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1667 | ldata->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); | |
1668 | if (!ldata->read_buf || !ldata->echo_buf) | |
b91939f5 | 1669 | goto err_free_bufs; |
0b4068a1 | 1670 | |
70ece7a7 | 1671 | tty->disc_data = ldata; |
b66f4fa5 | 1672 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1673 | ldata->column = 0; |
f6c8dbe6 | 1674 | ldata->minimum_to_wake = 1; |
1da177e4 | 1675 | tty->closing = 0; |
b66f4fa5 PH |
1676 | /* indicate buffer work may resume */ |
1677 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1678 | n_tty_set_termios(tty, NULL); | |
1679 | tty_unthrottle(tty); | |
70ece7a7 | 1680 | |
1da177e4 | 1681 | return 0; |
b91939f5 | 1682 | err_free_bufs: |
ba2e68ac JS |
1683 | kfree(ldata->read_buf); |
1684 | kfree(ldata->echo_buf); | |
70ece7a7 JS |
1685 | kfree(ldata); |
1686 | err: | |
b91939f5 | 1687 | return -ENOMEM; |
1da177e4 LT |
1688 | } |
1689 | ||
1690 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1691 | { | |
53c5ee2c JS |
1692 | struct n_tty_data *ldata = tty->disc_data; |
1693 | ||
e043e42b | 1694 | tty_flush_to_ldisc(tty); |
53c5ee2c | 1695 | if (ldata->icanon && !L_EXTPROC(tty)) { |
ba2e68ac | 1696 | if (ldata->canon_data) |
1da177e4 | 1697 | return 1; |
ba2e68ac | 1698 | } else if (ldata->read_cnt >= (amt ? amt : 1)) |
1da177e4 LT |
1699 | return 1; |
1700 | ||
1701 | return 0; | |
1702 | } | |
1703 | ||
1704 | /** | |
bbd20759 | 1705 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1706 | * @tty: terminal device |
1707 | * @b: user data | |
1708 | * @nr: size of data | |
1709 | * | |
11a96d18 | 1710 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1711 | * ICANON is off; it copies characters straight from the tty queue to |
1712 | * user space directly. It can be profitably called twice; once to | |
1713 | * drain the space from the tail pointer to the (physical) end of the | |
1714 | * buffer, and once to drain the space from the (physical) beginning of | |
1715 | * the buffer to head pointer. | |
1716 | * | |
bddc7152 | 1717 | * Called under the ldata->atomic_read_lock sem |
1da177e4 LT |
1718 | * |
1719 | */ | |
4edf1827 | 1720 | |
33f0f88f | 1721 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1722 | unsigned char __user **b, |
1723 | size_t *nr) | |
1724 | ||
1725 | { | |
53c5ee2c | 1726 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1727 | int retval; |
1728 | size_t n; | |
1729 | unsigned long flags; | |
3fa10cc8 | 1730 | bool is_eof; |
1da177e4 LT |
1731 | |
1732 | retval = 0; | |
98001214 | 1733 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 1734 | n = min(ldata->read_cnt, N_TTY_BUF_SIZE - ldata->read_tail); |
1da177e4 | 1735 | n = min(*nr, n); |
98001214 | 1736 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 | 1737 | if (n) { |
ba2e68ac | 1738 | retval = copy_to_user(*b, &ldata->read_buf[ldata->read_tail], n); |
1da177e4 | 1739 | n -= retval; |
3fa10cc8 | 1740 | is_eof = n == 1 && |
ba2e68ac JS |
1741 | ldata->read_buf[ldata->read_tail] == EOF_CHAR(tty); |
1742 | tty_audit_add_data(tty, &ldata->read_buf[ldata->read_tail], n, | |
53c5ee2c | 1743 | ldata->icanon); |
98001214 | 1744 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac JS |
1745 | ldata->read_tail = (ldata->read_tail + n) & (N_TTY_BUF_SIZE-1); |
1746 | ldata->read_cnt -= n; | |
26df6d13 | 1747 | /* Turn single EOF into zero-length read */ |
ba2e68ac | 1748 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !ldata->read_cnt) |
3fa10cc8 | 1749 | n = 0; |
98001214 | 1750 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1751 | *b += n; |
1752 | *nr -= n; | |
1753 | } | |
1754 | return retval; | |
1755 | } | |
1756 | ||
88bb0de3 | 1757 | /** |
32f13521 | 1758 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1759 | * @tty: terminal device |
1760 | * @b: user data | |
1761 | * @nr: size of data | |
1762 | * | |
1763 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1764 | * it copies one line of input up to and including the line-delimiting |
1765 | * character into the user-space buffer. | |
88bb0de3 PH |
1766 | * |
1767 | * Called under the atomic_read_lock mutex | |
1768 | */ | |
1769 | ||
32f13521 PH |
1770 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
1771 | unsigned char __user **b, | |
1772 | size_t *nr) | |
88bb0de3 PH |
1773 | { |
1774 | struct n_tty_data *ldata = tty->disc_data; | |
1775 | unsigned long flags; | |
32f13521 PH |
1776 | size_t n, size, more, c; |
1777 | unsigned long eol; | |
1778 | int ret, tail, found = 0; | |
88bb0de3 PH |
1779 | |
1780 | /* N.B. avoid overrun if nr == 0 */ | |
32f13521 | 1781 | |
88bb0de3 | 1782 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
32f13521 PH |
1783 | |
1784 | n = min_t(size_t, *nr, ldata->read_cnt); | |
1785 | if (!n) { | |
88bb0de3 | 1786 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
32f13521 PH |
1787 | return 0; |
1788 | } | |
88bb0de3 | 1789 | |
32f13521 PH |
1790 | tail = ldata->read_tail; |
1791 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); | |
1792 | ||
1793 | n_tty_trace("%s: nr:%zu tail:%d n:%zu size:%zu\n", | |
1794 | __func__, *nr, tail, n, size); | |
1795 | ||
1796 | eol = find_next_bit(ldata->read_flags, size, tail); | |
1797 | more = n - (size - tail); | |
1798 | if (eol == N_TTY_BUF_SIZE && more) { | |
1799 | /* scan wrapped without finding set bit */ | |
1800 | eol = find_next_bit(ldata->read_flags, more, 0); | |
1801 | if (eol != more) | |
1802 | found = 1; | |
1803 | } else if (eol != size) | |
1804 | found = 1; | |
1805 | ||
1806 | size = N_TTY_BUF_SIZE - tail; | |
1807 | n = (found + eol + size) & (N_TTY_BUF_SIZE - 1); | |
1808 | c = n; | |
1809 | ||
1810 | if (found && ldata->read_buf[eol] == __DISABLED_CHAR) | |
1811 | n--; | |
1812 | ||
1813 | n_tty_trace("%s: eol:%lu found:%d n:%zu c:%zu size:%zu more:%zu\n", | |
1814 | __func__, eol, found, n, c, size, more); | |
1815 | ||
1816 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); | |
1817 | ||
1818 | if (n > size) { | |
1819 | ret = copy_to_user(*b, &ldata->read_buf[tail], size); | |
1820 | if (ret) | |
1821 | return -EFAULT; | |
1822 | ret = copy_to_user(*b + size, ldata->read_buf, n - size); | |
1823 | } else | |
1824 | ret = copy_to_user(*b, &ldata->read_buf[tail], n); | |
1825 | ||
1826 | if (ret) | |
1827 | return -EFAULT; | |
1828 | *b += n; | |
1829 | *nr -= n; | |
1830 | ||
1831 | raw_spin_lock_irqsave(&ldata->read_lock, flags); | |
1832 | ldata->read_tail = (ldata->read_tail + c) & (N_TTY_BUF_SIZE - 1); | |
1833 | ldata->read_cnt -= c; | |
1834 | if (found) { | |
1835 | __clear_bit(eol, ldata->read_flags); | |
1836 | /* this test should be redundant: | |
1837 | * we shouldn't be reading data if | |
1838 | * canon_data is 0 | |
1839 | */ | |
1840 | if (--ldata->canon_data < 0) | |
1841 | ldata->canon_data = 0; | |
88bb0de3 PH |
1842 | } |
1843 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); | |
1844 | ||
32f13521 PH |
1845 | if (found) |
1846 | tty_audit_push(tty); | |
88bb0de3 PH |
1847 | return 0; |
1848 | } | |
1849 | ||
cc4191dc | 1850 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1851 | size_t, loff_t *); |
1da177e4 LT |
1852 | |
1853 | /** | |
1854 | * job_control - check job control | |
1855 | * @tty: tty | |
1856 | * @file: file handle | |
1857 | * | |
1858 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1859 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1860 | * error code if action should be taken. |
04f378b1 | 1861 | * |
01a5e440 PH |
1862 | * Locking: redirected write test is safe |
1863 | * current->signal->tty check is safe | |
1864 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 1865 | */ |
4edf1827 | 1866 | |
1da177e4 LT |
1867 | static int job_control(struct tty_struct *tty, struct file *file) |
1868 | { | |
1869 | /* Job control check -- must be done at start and after | |
1870 | every sleep (POSIX.1 7.1.1.4). */ | |
1871 | /* NOTE: not yet done after every sleep pending a thorough | |
1872 | check of the logic of this change. -- jlc */ | |
1873 | /* don't stop on /dev/console */ | |
01a5e440 PH |
1874 | if (file->f_op->write == redirected_tty_write || |
1875 | current->signal->tty != tty) | |
1876 | return 0; | |
1877 | ||
1878 | spin_lock_irq(&tty->ctrl_lock); | |
1879 | if (!tty->pgrp) | |
1880 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
1881 | else if (task_pgrp(current) != tty->pgrp) { | |
1882 | spin_unlock_irq(&tty->ctrl_lock); | |
1883 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
1884 | return -EIO; | |
1885 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
1886 | set_thread_flag(TIF_SIGPENDING); | |
1887 | return -ERESTARTSYS; | |
1da177e4 | 1888 | } |
01a5e440 | 1889 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
1890 | return 0; |
1891 | } | |
4edf1827 | 1892 | |
1da177e4 LT |
1893 | |
1894 | /** | |
11a96d18 | 1895 | * n_tty_read - read function for tty |
1da177e4 LT |
1896 | * @tty: tty device |
1897 | * @file: file object | |
1898 | * @buf: userspace buffer pointer | |
1899 | * @nr: size of I/O | |
1900 | * | |
1901 | * Perform reads for the line discipline. We are guaranteed that the | |
1902 | * line discipline will not be closed under us but we may get multiple | |
1903 | * parallel readers and must handle this ourselves. We may also get | |
1904 | * a hangup. Always called in user context, may sleep. | |
1905 | * | |
1906 | * This code must be sure never to sleep through a hangup. | |
1907 | */ | |
4edf1827 | 1908 | |
11a96d18 | 1909 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1910 | unsigned char __user *buf, size_t nr) |
1911 | { | |
53c5ee2c | 1912 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1913 | unsigned char __user *b = buf; |
1914 | DECLARE_WAITQUEUE(wait, current); | |
1915 | int c; | |
1916 | int minimum, time; | |
1917 | ssize_t retval = 0; | |
1918 | ssize_t size; | |
1919 | long timeout; | |
1920 | unsigned long flags; | |
04f378b1 | 1921 | int packet; |
1da177e4 LT |
1922 | |
1923 | do_it_again: | |
1da177e4 | 1924 | c = job_control(tty, file); |
4edf1827 | 1925 | if (c < 0) |
1da177e4 | 1926 | return c; |
4edf1827 | 1927 | |
1da177e4 LT |
1928 | minimum = time = 0; |
1929 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 1930 | if (!ldata->icanon) { |
1da177e4 LT |
1931 | minimum = MIN_CHAR(tty); |
1932 | if (minimum) { | |
a6e54319 | 1933 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 1934 | if (time) |
f6c8dbe6 | 1935 | ldata->minimum_to_wake = 1; |
1da177e4 | 1936 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
1937 | (ldata->minimum_to_wake > minimum)) |
1938 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 1939 | } else { |
a6e54319 | 1940 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 1941 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
1942 | } |
1943 | } | |
1944 | ||
1945 | /* | |
1946 | * Internal serialization of reads. | |
1947 | */ | |
1948 | if (file->f_flags & O_NONBLOCK) { | |
bddc7152 | 1949 | if (!mutex_trylock(&ldata->atomic_read_lock)) |
1da177e4 | 1950 | return -EAGAIN; |
4edf1827 | 1951 | } else { |
bddc7152 | 1952 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) |
1da177e4 LT |
1953 | return -ERESTARTSYS; |
1954 | } | |
04f378b1 | 1955 | packet = tty->packet; |
1da177e4 LT |
1956 | |
1957 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
1958 | while (nr) { |
1959 | /* First test for status change. */ | |
04f378b1 | 1960 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
1961 | unsigned char cs; |
1962 | if (b != buf) | |
1963 | break; | |
04f378b1 | 1964 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
1965 | cs = tty->link->ctrl_status; |
1966 | tty->link->ctrl_status = 0; | |
04f378b1 | 1967 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 1968 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
1969 | retval = -EFAULT; |
1970 | b--; | |
1971 | break; | |
1972 | } | |
1973 | nr--; | |
1974 | break; | |
1975 | } | |
1976 | /* This statement must be first before checking for input | |
1977 | so that any interrupt will set the state back to | |
1978 | TASK_RUNNING. */ | |
1979 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 1980 | |
f6c8dbe6 | 1981 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 1982 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 1983 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 1984 | |
1da177e4 LT |
1985 | if (!input_available_p(tty, 0)) { |
1986 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
1987 | retval = -EIO; | |
1988 | break; | |
1989 | } | |
1990 | if (tty_hung_up_p(file)) | |
1991 | break; | |
1992 | if (!timeout) | |
1993 | break; | |
1994 | if (file->f_flags & O_NONBLOCK) { | |
1995 | retval = -EAGAIN; | |
1996 | break; | |
1997 | } | |
1998 | if (signal_pending(current)) { | |
1999 | retval = -ERESTARTSYS; | |
2000 | break; | |
2001 | } | |
55db4c64 | 2002 | n_tty_set_room(tty); |
1da177e4 | 2003 | timeout = schedule_timeout(timeout); |
1da177e4 LT |
2004 | continue; |
2005 | } | |
2006 | __set_current_state(TASK_RUNNING); | |
2007 | ||
2008 | /* Deal with packet mode. */ | |
04f378b1 | 2009 | if (packet && b == buf) { |
522ed776 | 2010 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
2011 | retval = -EFAULT; |
2012 | b--; | |
2013 | break; | |
2014 | } | |
2015 | nr--; | |
2016 | } | |
2017 | ||
53c5ee2c | 2018 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2019 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
1da177e4 LT |
2020 | if (retval) |
2021 | break; | |
2022 | } else { | |
2023 | int uncopied; | |
04f378b1 AC |
2024 | /* The copy function takes the read lock and handles |
2025 | locking internally for this case */ | |
1da177e4 LT |
2026 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2027 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2028 | if (uncopied) { | |
2029 | retval = -EFAULT; | |
2030 | break; | |
2031 | } | |
2032 | } | |
2033 | ||
2034 | /* If there is enough space in the read buffer now, let the | |
2035 | * low-level driver know. We use n_tty_chars_in_buffer() to | |
2036 | * check the buffer, as it now knows about canonical mode. | |
2037 | * Otherwise, if the driver is throttled and the line is | |
2038 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
2039 | * we won't get any more characters. | |
2040 | */ | |
e91e52e4 PH |
2041 | while (1) { |
2042 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
2043 | if (n_tty_chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
2044 | break; | |
2045 | if (!tty->count) | |
2046 | break; | |
55db4c64 | 2047 | n_tty_set_room(tty); |
e91e52e4 PH |
2048 | if (!tty_unthrottle_safe(tty)) |
2049 | break; | |
55db4c64 | 2050 | } |
e91e52e4 | 2051 | __tty_set_flow_change(tty, 0); |
1da177e4 LT |
2052 | |
2053 | if (b - buf >= minimum) | |
2054 | break; | |
2055 | if (time) | |
2056 | timeout = time; | |
2057 | } | |
bddc7152 | 2058 | mutex_unlock(&ldata->atomic_read_lock); |
1da177e4 LT |
2059 | remove_wait_queue(&tty->read_wait, &wait); |
2060 | ||
2061 | if (!waitqueue_active(&tty->read_wait)) | |
f6c8dbe6 | 2062 | ldata->minimum_to_wake = minimum; |
1da177e4 LT |
2063 | |
2064 | __set_current_state(TASK_RUNNING); | |
2065 | size = b - buf; | |
2066 | if (size) { | |
2067 | retval = size; | |
2068 | if (nr) | |
4edf1827 | 2069 | clear_bit(TTY_PUSH, &tty->flags); |
1da177e4 | 2070 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) |
bbd20759 | 2071 | goto do_it_again; |
1da177e4 | 2072 | |
55db4c64 | 2073 | n_tty_set_room(tty); |
1da177e4 LT |
2074 | return retval; |
2075 | } | |
2076 | ||
2077 | /** | |
11a96d18 | 2078 | * n_tty_write - write function for tty |
1da177e4 LT |
2079 | * @tty: tty device |
2080 | * @file: file object | |
2081 | * @buf: userspace buffer pointer | |
2082 | * @nr: size of I/O | |
2083 | * | |
a88a69c9 | 2084 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2085 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2086 | * and other such events. Since the receive code will echo characters, |
2087 | * thus calling driver write methods, the output_lock is used in | |
2088 | * the output processing functions called here as well as in the | |
2089 | * echo processing function to protect the column state and space | |
2090 | * left in the buffer. | |
1da177e4 LT |
2091 | * |
2092 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2093 | * |
2094 | * Locking: output_lock to protect column state and space left | |
2095 | * (note that the process_output*() functions take this | |
2096 | * lock themselves) | |
1da177e4 | 2097 | */ |
4edf1827 | 2098 | |
11a96d18 | 2099 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2100 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2101 | { |
2102 | const unsigned char *b = buf; | |
2103 | DECLARE_WAITQUEUE(wait, current); | |
2104 | int c; | |
2105 | ssize_t retval = 0; | |
2106 | ||
2107 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2108 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2109 | retval = tty_check_change(tty); | |
2110 | if (retval) | |
2111 | return retval; | |
2112 | } | |
2113 | ||
a88a69c9 JP |
2114 | /* Write out any echoed characters that are still pending */ |
2115 | process_echoes(tty); | |
300a6204 | 2116 | |
1da177e4 LT |
2117 | add_wait_queue(&tty->write_wait, &wait); |
2118 | while (1) { | |
2119 | set_current_state(TASK_INTERRUPTIBLE); | |
2120 | if (signal_pending(current)) { | |
2121 | retval = -ERESTARTSYS; | |
2122 | break; | |
2123 | } | |
2124 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2125 | retval = -EIO; | |
2126 | break; | |
2127 | } | |
582f5590 | 2128 | if (O_OPOST(tty)) { |
1da177e4 | 2129 | while (nr > 0) { |
a88a69c9 | 2130 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2131 | if (num < 0) { |
2132 | if (num == -EAGAIN) | |
2133 | break; | |
2134 | retval = num; | |
2135 | goto break_out; | |
2136 | } | |
2137 | b += num; | |
2138 | nr -= num; | |
2139 | if (nr == 0) | |
2140 | break; | |
2141 | c = *b; | |
a88a69c9 | 2142 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2143 | break; |
2144 | b++; nr--; | |
2145 | } | |
f34d7a5b AC |
2146 | if (tty->ops->flush_chars) |
2147 | tty->ops->flush_chars(tty); | |
1da177e4 | 2148 | } else { |
d6afe27b | 2149 | while (nr > 0) { |
f34d7a5b | 2150 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
2151 | if (c < 0) { |
2152 | retval = c; | |
2153 | goto break_out; | |
2154 | } | |
2155 | if (!c) | |
2156 | break; | |
2157 | b += c; | |
2158 | nr -= c; | |
1da177e4 | 2159 | } |
1da177e4 LT |
2160 | } |
2161 | if (!nr) | |
2162 | break; | |
2163 | if (file->f_flags & O_NONBLOCK) { | |
2164 | retval = -EAGAIN; | |
2165 | break; | |
2166 | } | |
2167 | schedule(); | |
2168 | } | |
2169 | break_out: | |
2170 | __set_current_state(TASK_RUNNING); | |
2171 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2172 | if (b - buf != nr && tty->fasync) |
2173 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
1da177e4 LT |
2174 | return (b - buf) ? b - buf : retval; |
2175 | } | |
2176 | ||
2177 | /** | |
11a96d18 | 2178 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2179 | * @tty: terminal device |
2180 | * @file: file accessing it | |
2181 | * @wait: poll table | |
2182 | * | |
2183 | * Called when the line discipline is asked to poll() for data or | |
2184 | * for special events. This code is not serialized with respect to | |
2185 | * other events save open/close. | |
2186 | * | |
2187 | * This code must be sure never to sleep through a hangup. | |
2188 | * Called without the kernel lock held - fine | |
1da177e4 | 2189 | */ |
4edf1827 | 2190 | |
11a96d18 | 2191 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2192 | poll_table *wait) |
1da177e4 | 2193 | { |
f6c8dbe6 | 2194 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2195 | unsigned int mask = 0; |
2196 | ||
2197 | poll_wait(file, &tty->read_wait, wait); | |
2198 | poll_wait(file, &tty->write_wait, wait); | |
2199 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2200 | mask |= POLLIN | POLLRDNORM; | |
2201 | if (tty->packet && tty->link->ctrl_status) | |
2202 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2203 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2204 | mask |= POLLHUP; | |
2205 | if (tty_hung_up_p(file)) | |
2206 | mask |= POLLHUP; | |
2207 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2208 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2209 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2210 | else |
f6c8dbe6 | 2211 | ldata->minimum_to_wake = 1; |
1da177e4 | 2212 | } |
f34d7a5b AC |
2213 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2214 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2215 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2216 | mask |= POLLOUT | POLLWRNORM; |
2217 | return mask; | |
2218 | } | |
2219 | ||
57c94121 | 2220 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 AC |
2221 | { |
2222 | int nr, head, tail; | |
2223 | ||
ba2e68ac | 2224 | if (!ldata->canon_data) |
47afa7a5 | 2225 | return 0; |
ba2e68ac JS |
2226 | head = ldata->canon_head; |
2227 | tail = ldata->read_tail; | |
47afa7a5 AC |
2228 | nr = (head - tail) & (N_TTY_BUF_SIZE-1); |
2229 | /* Skip EOF-chars.. */ | |
2230 | while (head != tail) { | |
3fe780b3 | 2231 | if (test_bit(tail, ldata->read_flags) && |
ba2e68ac | 2232 | ldata->read_buf[tail] == __DISABLED_CHAR) |
47afa7a5 AC |
2233 | nr--; |
2234 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
2235 | } | |
2236 | return nr; | |
2237 | } | |
2238 | ||
2239 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2240 | unsigned int cmd, unsigned long arg) | |
2241 | { | |
ba2e68ac | 2242 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2243 | int retval; |
2244 | ||
2245 | switch (cmd) { | |
2246 | case TIOCOUTQ: | |
2247 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2248 | case TIOCINQ: | |
17b82060 | 2249 | /* FIXME: Locking */ |
ba2e68ac | 2250 | retval = ldata->read_cnt; |
47afa7a5 | 2251 | if (L_ICANON(tty)) |
57c94121 | 2252 | retval = inq_canon(ldata); |
47afa7a5 AC |
2253 | return put_user(retval, (unsigned int __user *) arg); |
2254 | default: | |
2255 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2256 | } | |
2257 | } | |
2258 | ||
f6c8dbe6 PH |
2259 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2260 | { | |
2261 | struct n_tty_data *ldata = tty->disc_data; | |
2262 | ||
2263 | if (!waitqueue_active(&tty->read_wait)) { | |
2264 | if (on) | |
2265 | ldata->minimum_to_wake = 1; | |
2266 | else if (!tty->fasync) | |
2267 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2268 | } | |
2269 | } | |
2270 | ||
a352def2 | 2271 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2272 | .magic = TTY_LDISC_MAGIC, |
2273 | .name = "n_tty", | |
2274 | .open = n_tty_open, | |
2275 | .close = n_tty_close, | |
2276 | .flush_buffer = n_tty_flush_buffer, | |
2277 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2278 | .read = n_tty_read, |
2279 | .write = n_tty_write, | |
e10cc1df PF |
2280 | .ioctl = n_tty_ioctl, |
2281 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2282 | .poll = n_tty_poll, |
e10cc1df | 2283 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2284 | .write_wakeup = n_tty_write_wakeup, |
2285 | .fasync = n_tty_fasync, | |
24a89d1c | 2286 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2287 | }; |
572b9adb RG |
2288 | |
2289 | /** | |
2290 | * n_tty_inherit_ops - inherit N_TTY methods | |
2291 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2292 | * | |
593fb1ae | 2293 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2294 | * methods. |
2295 | */ | |
2296 | ||
2297 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2298 | { | |
2299 | *ops = tty_ldisc_N_TTY; | |
2300 | ops->owner = NULL; | |
2301 | ops->refcount = ops->flags = 0; | |
2302 | } | |
2303 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |