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 | |
a19d0c6a | 280 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
1da177e4 | 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 | ||
a19d0c6a PH |
298 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
299 | { | |
47534084 | 300 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
a19d0c6a PH |
301 | return chars_in_buffer(tty); |
302 | } | |
303 | ||
1da177e4 LT |
304 | /** |
305 | * is_utf8_continuation - utf8 multibyte check | |
306 | * @c: byte to check | |
307 | * | |
308 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
309 | * character. We use this to correctly compute the on screen size | |
310 | * of the character when printing | |
311 | */ | |
4edf1827 | 312 | |
1da177e4 LT |
313 | static inline int is_utf8_continuation(unsigned char c) |
314 | { | |
315 | return (c & 0xc0) == 0x80; | |
316 | } | |
317 | ||
318 | /** | |
319 | * is_continuation - multibyte check | |
320 | * @c: byte to check | |
321 | * | |
322 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
323 | * character and the terminal is in unicode mode. | |
324 | */ | |
4edf1827 | 325 | |
1da177e4 LT |
326 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
327 | { | |
328 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
329 | } | |
330 | ||
331 | /** | |
a88a69c9 | 332 | * do_output_char - output one character |
1da177e4 LT |
333 | * @c: character (or partial unicode symbol) |
334 | * @tty: terminal device | |
a88a69c9 | 335 | * @space: space available in tty driver write buffer |
1da177e4 | 336 | * |
a88a69c9 JP |
337 | * This is a helper function that handles one output character |
338 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
339 | * doing OPOST processing and putting the results in the |
340 | * tty driver's write buffer. | |
a88a69c9 JP |
341 | * |
342 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
343 | * and NLDLY. They simply aren't relevant in the world today. | |
344 | * If you ever need them, add them here. | |
1da177e4 | 345 | * |
a88a69c9 JP |
346 | * Returns the number of bytes of buffer space used or -1 if |
347 | * no space left. | |
348 | * | |
349 | * Locking: should be called under the output_lock to protect | |
350 | * the column state and space left in the buffer | |
1da177e4 | 351 | */ |
4edf1827 | 352 | |
a88a69c9 | 353 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 354 | { |
53c5ee2c | 355 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 356 | int spaces; |
1da177e4 | 357 | |
1da177e4 LT |
358 | if (!space) |
359 | return -1; | |
300a6204 | 360 | |
a88a69c9 JP |
361 | switch (c) { |
362 | case '\n': | |
363 | if (O_ONLRET(tty)) | |
53c5ee2c | 364 | ldata->column = 0; |
a88a69c9 JP |
365 | if (O_ONLCR(tty)) { |
366 | if (space < 2) | |
367 | return -1; | |
ba2e68ac | 368 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 369 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
370 | return 2; |
371 | } | |
ba2e68ac | 372 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
373 | break; |
374 | case '\r': | |
53c5ee2c | 375 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
376 | return 0; |
377 | if (O_OCRNL(tty)) { | |
378 | c = '\n'; | |
379 | if (O_ONLRET(tty)) | |
ba2e68ac | 380 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 381 | break; |
a88a69c9 | 382 | } |
ba2e68ac | 383 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
384 | break; |
385 | case '\t': | |
53c5ee2c | 386 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
387 | if (O_TABDLY(tty) == XTABS) { |
388 | if (space < spaces) | |
389 | return -1; | |
53c5ee2c | 390 | ldata->column += spaces; |
a88a69c9 JP |
391 | tty->ops->write(tty, " ", spaces); |
392 | return spaces; | |
1da177e4 | 393 | } |
53c5ee2c | 394 | ldata->column += spaces; |
a88a69c9 JP |
395 | break; |
396 | case '\b': | |
53c5ee2c JS |
397 | if (ldata->column > 0) |
398 | ldata->column--; | |
a88a69c9 JP |
399 | break; |
400 | default: | |
a59c0d6f JP |
401 | if (!iscntrl(c)) { |
402 | if (O_OLCUC(tty)) | |
403 | c = toupper(c); | |
404 | if (!is_continuation(c, tty)) | |
53c5ee2c | 405 | ldata->column++; |
a59c0d6f | 406 | } |
a88a69c9 | 407 | break; |
1da177e4 | 408 | } |
a88a69c9 | 409 | |
f34d7a5b | 410 | tty_put_char(tty, c); |
a88a69c9 JP |
411 | return 1; |
412 | } | |
413 | ||
414 | /** | |
415 | * process_output - output post processor | |
416 | * @c: character (or partial unicode symbol) | |
417 | * @tty: terminal device | |
418 | * | |
ee5aa7b8 JP |
419 | * Output one character with OPOST processing. |
420 | * Returns -1 when the output device is full and the character | |
421 | * must be retried. | |
a88a69c9 JP |
422 | * |
423 | * Locking: output_lock to protect column state and space left | |
424 | * (also, this is called from n_tty_write under the | |
425 | * tty layer write lock) | |
426 | */ | |
427 | ||
428 | static int process_output(unsigned char c, struct tty_struct *tty) | |
429 | { | |
bddc7152 | 430 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
431 | int space, retval; |
432 | ||
bddc7152 | 433 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
434 | |
435 | space = tty_write_room(tty); | |
436 | retval = do_output_char(c, tty, space); | |
437 | ||
bddc7152 | 438 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
439 | if (retval < 0) |
440 | return -1; | |
441 | else | |
442 | return 0; | |
1da177e4 LT |
443 | } |
444 | ||
445 | /** | |
a88a69c9 | 446 | * process_output_block - block post processor |
1da177e4 | 447 | * @tty: terminal device |
ee5aa7b8 JP |
448 | * @buf: character buffer |
449 | * @nr: number of bytes to output | |
450 | * | |
451 | * Output a block of characters with OPOST processing. | |
452 | * Returns the number of characters output. | |
1da177e4 LT |
453 | * |
454 | * This path is used to speed up block console writes, among other | |
455 | * things when processing blocks of output data. It handles only | |
456 | * the simple cases normally found and helps to generate blocks of | |
457 | * symbols for the console driver and thus improve performance. | |
458 | * | |
a88a69c9 JP |
459 | * Locking: output_lock to protect column state and space left |
460 | * (also, this is called from n_tty_write under the | |
461 | * tty layer write lock) | |
1da177e4 | 462 | */ |
4edf1827 | 463 | |
a88a69c9 JP |
464 | static ssize_t process_output_block(struct tty_struct *tty, |
465 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 466 | { |
53c5ee2c | 467 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 468 | int space; |
bbd20759 | 469 | int i; |
1da177e4 LT |
470 | const unsigned char *cp; |
471 | ||
bddc7152 | 472 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 473 | |
f34d7a5b | 474 | space = tty_write_room(tty); |
300a6204 | 475 | if (!space) { |
bddc7152 | 476 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 477 | return 0; |
a88a69c9 | 478 | } |
1da177e4 LT |
479 | if (nr > space) |
480 | nr = space; | |
481 | ||
482 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
483 | unsigned char c = *cp; |
484 | ||
485 | switch (c) { | |
1da177e4 LT |
486 | case '\n': |
487 | if (O_ONLRET(tty)) | |
53c5ee2c | 488 | ldata->column = 0; |
1da177e4 LT |
489 | if (O_ONLCR(tty)) |
490 | goto break_out; | |
ba2e68ac | 491 | ldata->canon_column = ldata->column; |
1da177e4 LT |
492 | break; |
493 | case '\r': | |
53c5ee2c | 494 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
495 | goto break_out; |
496 | if (O_OCRNL(tty)) | |
497 | goto break_out; | |
ba2e68ac | 498 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
499 | break; |
500 | case '\t': | |
501 | goto break_out; | |
502 | case '\b': | |
53c5ee2c JS |
503 | if (ldata->column > 0) |
504 | ldata->column--; | |
1da177e4 LT |
505 | break; |
506 | default: | |
a59c0d6f JP |
507 | if (!iscntrl(c)) { |
508 | if (O_OLCUC(tty)) | |
509 | goto break_out; | |
510 | if (!is_continuation(c, tty)) | |
53c5ee2c | 511 | ldata->column++; |
a59c0d6f | 512 | } |
1da177e4 LT |
513 | break; |
514 | } | |
515 | } | |
516 | break_out: | |
f34d7a5b | 517 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 518 | |
bddc7152 | 519 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
520 | return i; |
521 | } | |
522 | ||
a88a69c9 JP |
523 | /** |
524 | * process_echoes - write pending echo characters | |
525 | * @tty: terminal device | |
526 | * | |
527 | * Write previously buffered echo (and other ldisc-generated) | |
528 | * characters to the tty. | |
529 | * | |
530 | * Characters generated by the ldisc (including echoes) need to | |
531 | * be buffered because the driver's write buffer can fill during | |
532 | * heavy program output. Echoing straight to the driver will | |
533 | * often fail under these conditions, causing lost characters and | |
534 | * resulting mismatches of ldisc state information. | |
535 | * | |
536 | * Since the ldisc state must represent the characters actually sent | |
537 | * to the driver at the time of the write, operations like certain | |
538 | * changes in column state are also saved in the buffer and executed | |
539 | * here. | |
540 | * | |
541 | * A circular fifo buffer is used so that the most recent characters | |
542 | * are prioritized. Also, when control characters are echoed with a | |
543 | * prefixed "^", the pair is treated atomically and thus not separated. | |
544 | * | |
545 | * Locking: output_lock to protect column state and space left, | |
546 | * echo_lock to protect the echo buffer | |
547 | */ | |
548 | ||
549 | static void process_echoes(struct tty_struct *tty) | |
550 | { | |
53c5ee2c | 551 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
552 | int space, nr; |
553 | unsigned char c; | |
554 | unsigned char *cp, *buf_end; | |
555 | ||
ba2e68ac | 556 | if (!ldata->echo_cnt) |
a88a69c9 JP |
557 | return; |
558 | ||
bddc7152 JS |
559 | mutex_lock(&ldata->output_lock); |
560 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
561 | |
562 | space = tty_write_room(tty); | |
563 | ||
ba2e68ac JS |
564 | buf_end = ldata->echo_buf + N_TTY_BUF_SIZE; |
565 | cp = ldata->echo_buf + ldata->echo_pos; | |
566 | nr = ldata->echo_cnt; | |
a88a69c9 JP |
567 | while (nr > 0) { |
568 | c = *cp; | |
569 | if (c == ECHO_OP_START) { | |
570 | unsigned char op; | |
571 | unsigned char *opp; | |
572 | int no_space_left = 0; | |
573 | ||
574 | /* | |
575 | * If the buffer byte is the start of a multi-byte | |
576 | * operation, get the next byte, which is either the | |
577 | * op code or a control character value. | |
578 | */ | |
579 | opp = cp + 1; | |
580 | if (opp == buf_end) | |
581 | opp -= N_TTY_BUF_SIZE; | |
582 | op = *opp; | |
300a6204 | 583 | |
a88a69c9 JP |
584 | switch (op) { |
585 | unsigned int num_chars, num_bs; | |
586 | ||
587 | case ECHO_OP_ERASE_TAB: | |
588 | if (++opp == buf_end) | |
589 | opp -= N_TTY_BUF_SIZE; | |
590 | num_chars = *opp; | |
591 | ||
592 | /* | |
593 | * Determine how many columns to go back | |
594 | * in order to erase the tab. | |
595 | * This depends on the number of columns | |
596 | * used by other characters within the tab | |
597 | * area. If this (modulo 8) count is from | |
598 | * the start of input rather than from a | |
599 | * previous tab, we offset by canon column. | |
600 | * Otherwise, tab spacing is normal. | |
601 | */ | |
602 | if (!(num_chars & 0x80)) | |
ba2e68ac | 603 | num_chars += ldata->canon_column; |
a88a69c9 JP |
604 | num_bs = 8 - (num_chars & 7); |
605 | ||
606 | if (num_bs > space) { | |
607 | no_space_left = 1; | |
608 | break; | |
609 | } | |
610 | space -= num_bs; | |
611 | while (num_bs--) { | |
612 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
613 | if (ldata->column > 0) |
614 | ldata->column--; | |
a88a69c9 JP |
615 | } |
616 | cp += 3; | |
617 | nr -= 3; | |
618 | break; | |
619 | ||
620 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 621 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
622 | cp += 2; |
623 | nr -= 2; | |
624 | break; | |
625 | ||
626 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
627 | if (ldata->column > 0) |
628 | ldata->column--; | |
a88a69c9 JP |
629 | cp += 2; |
630 | nr -= 2; | |
631 | break; | |
632 | ||
633 | case ECHO_OP_START: | |
634 | /* This is an escaped echo op start code */ | |
635 | if (!space) { | |
636 | no_space_left = 1; | |
637 | break; | |
638 | } | |
639 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 640 | ldata->column++; |
a88a69c9 JP |
641 | space--; |
642 | cp += 2; | |
643 | nr -= 2; | |
644 | break; | |
645 | ||
646 | default: | |
a88a69c9 | 647 | /* |
62b26358 JP |
648 | * If the op is not a special byte code, |
649 | * it is a ctrl char tagged to be echoed | |
650 | * as "^X" (where X is the letter | |
651 | * representing the control char). | |
652 | * Note that we must ensure there is | |
653 | * enough space for the whole ctrl pair. | |
654 | * | |
a88a69c9 | 655 | */ |
62b26358 JP |
656 | if (space < 2) { |
657 | no_space_left = 1; | |
658 | break; | |
659 | } | |
660 | tty_put_char(tty, '^'); | |
661 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 662 | ldata->column += 2; |
62b26358 | 663 | space -= 2; |
a88a69c9 JP |
664 | cp += 2; |
665 | nr -= 2; | |
666 | } | |
667 | ||
668 | if (no_space_left) | |
669 | break; | |
670 | } else { | |
582f5590 | 671 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
672 | int retval = do_output_char(c, tty, space); |
673 | if (retval < 0) | |
674 | break; | |
675 | space -= retval; | |
676 | } else { | |
677 | if (!space) | |
678 | break; | |
679 | tty_put_char(tty, c); | |
680 | space -= 1; | |
681 | } | |
a88a69c9 JP |
682 | cp += 1; |
683 | nr -= 1; | |
684 | } | |
685 | ||
686 | /* When end of circular buffer reached, wrap around */ | |
687 | if (cp >= buf_end) | |
688 | cp -= N_TTY_BUF_SIZE; | |
689 | } | |
690 | ||
691 | if (nr == 0) { | |
ba2e68ac JS |
692 | ldata->echo_pos = 0; |
693 | ldata->echo_cnt = 0; | |
53c5ee2c | 694 | ldata->echo_overrun = 0; |
a88a69c9 | 695 | } else { |
ba2e68ac JS |
696 | int num_processed = ldata->echo_cnt - nr; |
697 | ldata->echo_pos += num_processed; | |
698 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; | |
699 | ldata->echo_cnt = nr; | |
a88a69c9 | 700 | if (num_processed > 0) |
53c5ee2c | 701 | ldata->echo_overrun = 0; |
a88a69c9 JP |
702 | } |
703 | ||
bddc7152 JS |
704 | mutex_unlock(&ldata->echo_lock); |
705 | mutex_unlock(&ldata->output_lock); | |
a88a69c9 JP |
706 | |
707 | if (tty->ops->flush_chars) | |
708 | tty->ops->flush_chars(tty); | |
709 | } | |
710 | ||
711 | /** | |
712 | * add_echo_byte - add a byte to the echo buffer | |
713 | * @c: unicode byte to echo | |
57c94121 | 714 | * @ldata: n_tty data |
a88a69c9 JP |
715 | * |
716 | * Add a character or operation byte to the echo buffer. | |
717 | * | |
718 | * Should be called under the echo lock to protect the echo buffer. | |
719 | */ | |
720 | ||
57c94121 | 721 | static void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 JP |
722 | { |
723 | int new_byte_pos; | |
724 | ||
ba2e68ac | 725 | if (ldata->echo_cnt == N_TTY_BUF_SIZE) { |
a88a69c9 | 726 | /* Circular buffer is already at capacity */ |
ba2e68ac | 727 | new_byte_pos = ldata->echo_pos; |
a88a69c9 JP |
728 | |
729 | /* | |
730 | * Since the buffer start position needs to be advanced, | |
731 | * be sure to step by a whole operation byte group. | |
732 | */ | |
ba2e68ac JS |
733 | if (ldata->echo_buf[ldata->echo_pos] == ECHO_OP_START) { |
734 | if (ldata->echo_buf[(ldata->echo_pos + 1) & | |
a88a69c9 JP |
735 | (N_TTY_BUF_SIZE - 1)] == |
736 | ECHO_OP_ERASE_TAB) { | |
ba2e68ac JS |
737 | ldata->echo_pos += 3; |
738 | ldata->echo_cnt -= 2; | |
a88a69c9 | 739 | } else { |
ba2e68ac JS |
740 | ldata->echo_pos += 2; |
741 | ldata->echo_cnt -= 1; | |
a88a69c9 JP |
742 | } |
743 | } else { | |
ba2e68ac | 744 | ldata->echo_pos++; |
a88a69c9 | 745 | } |
ba2e68ac | 746 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; |
a88a69c9 | 747 | |
53c5ee2c | 748 | ldata->echo_overrun = 1; |
a88a69c9 | 749 | } else { |
ba2e68ac | 750 | new_byte_pos = ldata->echo_pos + ldata->echo_cnt; |
a88a69c9 | 751 | new_byte_pos &= N_TTY_BUF_SIZE - 1; |
ba2e68ac | 752 | ldata->echo_cnt++; |
a88a69c9 JP |
753 | } |
754 | ||
ba2e68ac | 755 | ldata->echo_buf[new_byte_pos] = c; |
a88a69c9 JP |
756 | } |
757 | ||
758 | /** | |
759 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 760 | * @ldata: n_tty data |
a88a69c9 JP |
761 | * |
762 | * Add an operation to the echo buffer to move back one column. | |
763 | * | |
764 | * Locking: echo_lock to protect the echo buffer | |
765 | */ | |
766 | ||
57c94121 | 767 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 768 | { |
bddc7152 | 769 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
770 | add_echo_byte(ECHO_OP_START, ldata); |
771 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
bddc7152 | 772 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
773 | } |
774 | ||
775 | /** | |
776 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 777 | * @ldata: n_tty data |
a88a69c9 JP |
778 | * |
779 | * Add an operation to the echo buffer to set the canon column | |
780 | * to the current column. | |
781 | * | |
782 | * Locking: echo_lock to protect the echo buffer | |
783 | */ | |
784 | ||
57c94121 | 785 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 786 | { |
bddc7152 | 787 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
788 | add_echo_byte(ECHO_OP_START, ldata); |
789 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
bddc7152 | 790 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
791 | } |
792 | ||
793 | /** | |
794 | * echo_erase_tab - add operation to erase a tab | |
795 | * @num_chars: number of character columns already used | |
796 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 797 | * @ldata: n_tty data |
a88a69c9 JP |
798 | * |
799 | * Add an operation to the echo buffer to erase a tab. | |
800 | * | |
801 | * Called by the eraser function, which knows how many character | |
802 | * columns have been used since either a previous tab or the start | |
803 | * of input. This information will be used later, along with | |
804 | * canon column (if applicable), to go back the correct number | |
805 | * of columns. | |
806 | * | |
807 | * Locking: echo_lock to protect the echo buffer | |
808 | */ | |
809 | ||
810 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 811 | struct n_tty_data *ldata) |
a88a69c9 | 812 | { |
bddc7152 | 813 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 814 | |
57c94121 JS |
815 | add_echo_byte(ECHO_OP_START, ldata); |
816 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
817 | |
818 | /* We only need to know this modulo 8 (tab spacing) */ | |
819 | num_chars &= 7; | |
820 | ||
821 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
822 | if (after_tab) | |
823 | num_chars |= 0x80; | |
300a6204 | 824 | |
57c94121 | 825 | add_echo_byte(num_chars, ldata); |
a88a69c9 | 826 | |
bddc7152 | 827 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
828 | } |
829 | ||
830 | /** | |
831 | * echo_char_raw - echo a character raw | |
832 | * @c: unicode byte to echo | |
833 | * @tty: terminal device | |
834 | * | |
835 | * Echo user input back onto the screen. This must be called only when | |
836 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
837 | * | |
838 | * This variant does not treat control characters specially. | |
839 | * | |
840 | * Locking: echo_lock to protect the echo buffer | |
841 | */ | |
842 | ||
57c94121 | 843 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 844 | { |
bddc7152 | 845 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 846 | if (c == ECHO_OP_START) { |
57c94121 JS |
847 | add_echo_byte(ECHO_OP_START, ldata); |
848 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 849 | } else { |
57c94121 | 850 | add_echo_byte(c, ldata); |
a88a69c9 | 851 | } |
bddc7152 | 852 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 | 853 | } |
1da177e4 | 854 | |
1da177e4 | 855 | /** |
a88a69c9 | 856 | * echo_char - echo a character |
1da177e4 LT |
857 | * @c: unicode byte to echo |
858 | * @tty: terminal device | |
859 | * | |
4edf1827 | 860 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 861 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 862 | * |
62b26358 JP |
863 | * This variant tags control characters to be echoed as "^X" |
864 | * (where X is the letter representing the control char). | |
a88a69c9 JP |
865 | * |
866 | * Locking: echo_lock to protect the echo buffer | |
1da177e4 LT |
867 | */ |
868 | ||
869 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
870 | { | |
bddc7152 JS |
871 | struct n_tty_data *ldata = tty->disc_data; |
872 | ||
873 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
874 | |
875 | if (c == ECHO_OP_START) { | |
57c94121 JS |
876 | add_echo_byte(ECHO_OP_START, ldata); |
877 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 878 | } else { |
62b26358 | 879 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
880 | add_echo_byte(ECHO_OP_START, ldata); |
881 | add_echo_byte(c, ldata); | |
a88a69c9 JP |
882 | } |
883 | ||
bddc7152 | 884 | mutex_unlock(&ldata->echo_lock); |
1da177e4 LT |
885 | } |
886 | ||
17b82060 | 887 | /** |
a88a69c9 | 888 | * finish_erasing - complete erase |
57c94121 | 889 | * @ldata: n_tty data |
17b82060 | 890 | */ |
a88a69c9 | 891 | |
57c94121 | 892 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 893 | { |
53c5ee2c | 894 | if (ldata->erasing) { |
57c94121 | 895 | echo_char_raw('/', ldata); |
53c5ee2c | 896 | ldata->erasing = 0; |
1da177e4 LT |
897 | } |
898 | } | |
899 | ||
900 | /** | |
901 | * eraser - handle erase function | |
902 | * @c: character input | |
903 | * @tty: terminal device | |
904 | * | |
3a4fa0a2 | 905 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
906 | * present in the stream from the driver layer. Handles the complexities |
907 | * of UTF-8 multibyte symbols. | |
17b82060 | 908 | * |
a88a69c9 | 909 | * Locking: read_lock for tty buffers |
1da177e4 | 910 | */ |
4edf1827 | 911 | |
1da177e4 LT |
912 | static void eraser(unsigned char c, struct tty_struct *tty) |
913 | { | |
53c5ee2c | 914 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
915 | enum { ERASE, WERASE, KILL } kill_type; |
916 | int head, seen_alnums, cnt; | |
917 | unsigned long flags; | |
918 | ||
17b82060 | 919 | /* FIXME: locking needed ? */ |
ba2e68ac | 920 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 921 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
922 | return; |
923 | } | |
924 | if (c == ERASE_CHAR(tty)) | |
925 | kill_type = ERASE; | |
926 | else if (c == WERASE_CHAR(tty)) | |
927 | kill_type = WERASE; | |
928 | else { | |
929 | if (!L_ECHO(tty)) { | |
98001214 | 930 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 931 | ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) & |
1da177e4 | 932 | (N_TTY_BUF_SIZE - 1)); |
ba2e68ac | 933 | ldata->read_head = ldata->canon_head; |
98001214 | 934 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
935 | return; |
936 | } | |
937 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
98001214 | 938 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 939 | ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) & |
1da177e4 | 940 | (N_TTY_BUF_SIZE - 1)); |
ba2e68ac | 941 | ldata->read_head = ldata->canon_head; |
98001214 | 942 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
57c94121 | 943 | finish_erasing(ldata); |
1da177e4 LT |
944 | echo_char(KILL_CHAR(tty), tty); |
945 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
946 | if (L_ECHOK(tty)) | |
57c94121 | 947 | echo_char_raw('\n', ldata); |
1da177e4 LT |
948 | return; |
949 | } | |
950 | kill_type = KILL; | |
951 | } | |
952 | ||
953 | seen_alnums = 0; | |
17b82060 | 954 | /* FIXME: Locking ?? */ |
ba2e68ac JS |
955 | while (ldata->read_head != ldata->canon_head) { |
956 | head = ldata->read_head; | |
1da177e4 LT |
957 | |
958 | /* erase a single possibly multibyte character */ | |
959 | do { | |
960 | head = (head - 1) & (N_TTY_BUF_SIZE-1); | |
ba2e68ac JS |
961 | c = ldata->read_buf[head]; |
962 | } while (is_continuation(c, tty) && head != ldata->canon_head); | |
1da177e4 LT |
963 | |
964 | /* do not partially erase */ | |
965 | if (is_continuation(c, tty)) | |
966 | break; | |
967 | ||
968 | if (kill_type == WERASE) { | |
969 | /* Equivalent to BSD's ALTWERASE. */ | |
970 | if (isalnum(c) || c == '_') | |
971 | seen_alnums++; | |
972 | else if (seen_alnums) | |
973 | break; | |
974 | } | |
ba2e68ac | 975 | cnt = (ldata->read_head - head) & (N_TTY_BUF_SIZE-1); |
98001214 | 976 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac JS |
977 | ldata->read_head = head; |
978 | ldata->read_cnt -= cnt; | |
98001214 | 979 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
980 | if (L_ECHO(tty)) { |
981 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 982 | if (!ldata->erasing) { |
57c94121 | 983 | echo_char_raw('\\', ldata); |
53c5ee2c | 984 | ldata->erasing = 1; |
1da177e4 LT |
985 | } |
986 | /* if cnt > 1, output a multi-byte character */ | |
987 | echo_char(c, tty); | |
988 | while (--cnt > 0) { | |
989 | head = (head+1) & (N_TTY_BUF_SIZE-1); | |
57c94121 JS |
990 | echo_char_raw(ldata->read_buf[head], |
991 | ldata); | |
992 | echo_move_back_col(ldata); | |
1da177e4 LT |
993 | } |
994 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
995 | echo_char(ERASE_CHAR(tty), tty); | |
996 | } else if (c == '\t') { | |
a88a69c9 JP |
997 | unsigned int num_chars = 0; |
998 | int after_tab = 0; | |
ba2e68ac | 999 | unsigned long tail = ldata->read_head; |
a88a69c9 JP |
1000 | |
1001 | /* | |
1002 | * Count the columns used for characters | |
1003 | * since the start of input or after a | |
1004 | * previous tab. | |
1005 | * This info is used to go back the correct | |
1006 | * number of columns. | |
1007 | */ | |
ba2e68ac | 1008 | while (tail != ldata->canon_head) { |
a88a69c9 | 1009 | tail = (tail-1) & (N_TTY_BUF_SIZE-1); |
ba2e68ac | 1010 | c = ldata->read_buf[tail]; |
a88a69c9 JP |
1011 | if (c == '\t') { |
1012 | after_tab = 1; | |
1013 | break; | |
300a6204 | 1014 | } else if (iscntrl(c)) { |
1da177e4 | 1015 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1016 | num_chars += 2; |
1017 | } else if (!is_continuation(c, tty)) { | |
1018 | num_chars++; | |
1019 | } | |
1da177e4 | 1020 | } |
57c94121 | 1021 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1022 | } else { |
1023 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1024 | echo_char_raw('\b', ldata); |
1025 | echo_char_raw(' ', ldata); | |
1026 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1027 | } |
1028 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1029 | echo_char_raw('\b', ldata); |
1030 | echo_char_raw(' ', ldata); | |
1031 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1032 | } |
1033 | } | |
1034 | } | |
1035 | if (kill_type == ERASE) | |
1036 | break; | |
1037 | } | |
ba2e68ac | 1038 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1039 | finish_erasing(ldata); |
1da177e4 LT |
1040 | } |
1041 | ||
1042 | /** | |
1043 | * isig - handle the ISIG optio | |
1044 | * @sig: signal | |
1045 | * @tty: terminal | |
1da177e4 | 1046 | * |
8c985d18 PH |
1047 | * Called when a signal is being sent due to terminal input. |
1048 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1049 | * |
8c985d18 | 1050 | * Locking: ctrl_lock |
1da177e4 | 1051 | */ |
4edf1827 | 1052 | |
8c985d18 | 1053 | static inline void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1054 | { |
8c985d18 PH |
1055 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1056 | if (tty_pgrp) { | |
1057 | kill_pgrp(tty_pgrp, sig, 1); | |
1058 | put_pid(tty_pgrp); | |
1da177e4 LT |
1059 | } |
1060 | } | |
1061 | ||
1062 | /** | |
1063 | * n_tty_receive_break - handle break | |
1064 | * @tty: terminal | |
1065 | * | |
1066 | * An RS232 break event has been hit in the incoming bitstream. This | |
1067 | * can cause a variety of events depending upon the termios settings. | |
1068 | * | |
1069 | * Called from the receive_buf path so single threaded. | |
1070 | */ | |
4edf1827 | 1071 | |
1da177e4 LT |
1072 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1073 | { | |
57c94121 JS |
1074 | struct n_tty_data *ldata = tty->disc_data; |
1075 | ||
1da177e4 LT |
1076 | if (I_IGNBRK(tty)) |
1077 | return; | |
1078 | if (I_BRKINT(tty)) { | |
8c985d18 PH |
1079 | isig(SIGINT, tty); |
1080 | if (!L_NOFLSH(tty)) { | |
1081 | n_tty_flush_buffer(tty); | |
1082 | tty_driver_flush_buffer(tty); | |
1083 | } | |
1da177e4 LT |
1084 | return; |
1085 | } | |
1086 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1087 | put_tty_queue('\377', ldata); |
1088 | put_tty_queue('\0', ldata); | |
1da177e4 | 1089 | } |
57c94121 | 1090 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1091 | wake_up_interruptible(&tty->read_wait); |
1092 | } | |
1093 | ||
1094 | /** | |
1095 | * n_tty_receive_overrun - handle overrun reporting | |
1096 | * @tty: terminal | |
1097 | * | |
1098 | * Data arrived faster than we could process it. While the tty | |
1099 | * driver has flagged this the bits that were missed are gone | |
1100 | * forever. | |
1101 | * | |
1102 | * Called from the receive_buf path so single threaded. Does not | |
1103 | * need locking as num_overrun and overrun_time are function | |
1104 | * private. | |
1105 | */ | |
4edf1827 | 1106 | |
1da177e4 LT |
1107 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1108 | { | |
53c5ee2c | 1109 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1110 | char buf[64]; |
1111 | ||
53c5ee2c JS |
1112 | ldata->num_overrun++; |
1113 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1114 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1115 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1116 | tty_name(tty, buf), | |
53c5ee2c JS |
1117 | ldata->num_overrun); |
1118 | ldata->overrun_time = jiffies; | |
1119 | ldata->num_overrun = 0; | |
1da177e4 LT |
1120 | } |
1121 | } | |
1122 | ||
1123 | /** | |
1124 | * n_tty_receive_parity_error - error notifier | |
1125 | * @tty: terminal device | |
1126 | * @c: character | |
1127 | * | |
1128 | * Process a parity error and queue the right data to indicate | |
3a4fa0a2 | 1129 | * the error case if necessary. Locking as per n_tty_receive_buf. |
1da177e4 LT |
1130 | */ |
1131 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1132 | unsigned char c) | |
1133 | { | |
57c94121 JS |
1134 | struct n_tty_data *ldata = tty->disc_data; |
1135 | ||
4edf1827 | 1136 | if (I_IGNPAR(tty)) |
1da177e4 | 1137 | return; |
1da177e4 | 1138 | if (I_PARMRK(tty)) { |
57c94121 JS |
1139 | put_tty_queue('\377', ldata); |
1140 | put_tty_queue('\0', ldata); | |
1141 | put_tty_queue(c, ldata); | |
1da177e4 | 1142 | } else if (I_INPCK(tty)) |
57c94121 | 1143 | put_tty_queue('\0', ldata); |
1da177e4 | 1144 | else |
57c94121 | 1145 | put_tty_queue(c, ldata); |
1da177e4 LT |
1146 | wake_up_interruptible(&tty->read_wait); |
1147 | } | |
1148 | ||
1149 | /** | |
1150 | * n_tty_receive_char - perform processing | |
1151 | * @tty: terminal device | |
1152 | * @c: character | |
1153 | * | |
1154 | * Process an individual character of input received from the driver. | |
4edf1827 | 1155 | * This is serialized with respect to itself by the rules for the |
1da177e4 LT |
1156 | * driver above. |
1157 | */ | |
1158 | ||
1159 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1160 | { | |
53c5ee2c | 1161 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1162 | unsigned long flags; |
acc71bba | 1163 | int parmrk; |
1da177e4 | 1164 | |
53c5ee2c | 1165 | if (ldata->raw) { |
57c94121 | 1166 | put_tty_queue(c, ldata); |
1da177e4 LT |
1167 | return; |
1168 | } | |
4edf1827 | 1169 | |
1da177e4 LT |
1170 | if (I_ISTRIP(tty)) |
1171 | c &= 0x7f; | |
1172 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1173 | c = tolower(c); |
1da177e4 | 1174 | |
26df6d13 | 1175 | if (L_EXTPROC(tty)) { |
57c94121 | 1176 | put_tty_queue(c, ldata); |
26df6d13 | 1177 | return; |
1178 | } | |
1179 | ||
54d2a37e | 1180 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1181 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1182 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1183 | start_tty(tty); |
a88a69c9 JP |
1184 | process_echoes(tty); |
1185 | } | |
54d2a37e | 1186 | |
1da177e4 LT |
1187 | if (tty->closing) { |
1188 | if (I_IXON(tty)) { | |
a88a69c9 | 1189 | if (c == START_CHAR(tty)) { |
1da177e4 | 1190 | start_tty(tty); |
a88a69c9 | 1191 | process_echoes(tty); |
300a6204 | 1192 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1193 | stop_tty(tty); |
1194 | } | |
1195 | return; | |
1196 | } | |
1197 | ||
1198 | /* | |
1199 | * If the previous character was LNEXT, or we know that this | |
1200 | * character is not one of the characters that we'll have to | |
1201 | * handle specially, do shortcut processing to speed things | |
1202 | * up. | |
1203 | */ | |
3fe780b3 | 1204 | if (!test_bit(c, ldata->process_char_map) || ldata->lnext) { |
53c5ee2c | 1205 | ldata->lnext = 0; |
acc71bba | 1206 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ba2e68ac | 1207 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1208 | /* beep if no space */ |
7e94b1d9 JP |
1209 | if (L_ECHO(tty)) |
1210 | process_output('\a', tty); | |
acc71bba JP |
1211 | return; |
1212 | } | |
1213 | if (L_ECHO(tty)) { | |
57c94121 | 1214 | finish_erasing(ldata); |
1da177e4 | 1215 | /* Record the column of first canon char. */ |
ba2e68ac | 1216 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1217 | echo_set_canon_col(ldata); |
1da177e4 | 1218 | echo_char(c, tty); |
a88a69c9 | 1219 | process_echoes(tty); |
1da177e4 | 1220 | } |
acc71bba | 1221 | if (parmrk) |
57c94121 JS |
1222 | put_tty_queue(c, ldata); |
1223 | put_tty_queue(c, ldata); | |
1da177e4 LT |
1224 | return; |
1225 | } | |
4edf1827 | 1226 | |
1da177e4 LT |
1227 | if (I_IXON(tty)) { |
1228 | if (c == START_CHAR(tty)) { | |
1229 | start_tty(tty); | |
a88a69c9 | 1230 | process_echoes(tty); |
1da177e4 LT |
1231 | return; |
1232 | } | |
1233 | if (c == STOP_CHAR(tty)) { | |
1234 | stop_tty(tty); | |
1235 | return; | |
1236 | } | |
1237 | } | |
575537b3 | 1238 | |
1da177e4 LT |
1239 | if (L_ISIG(tty)) { |
1240 | int signal; | |
1241 | signal = SIGINT; | |
1242 | if (c == INTR_CHAR(tty)) | |
1243 | goto send_signal; | |
1244 | signal = SIGQUIT; | |
1245 | if (c == QUIT_CHAR(tty)) | |
1246 | goto send_signal; | |
1247 | signal = SIGTSTP; | |
1248 | if (c == SUSP_CHAR(tty)) { | |
1249 | send_signal: | |
ec5b1157 JP |
1250 | if (!L_NOFLSH(tty)) { |
1251 | n_tty_flush_buffer(tty); | |
f34d7a5b | 1252 | tty_driver_flush_buffer(tty); |
ec5b1157 | 1253 | } |
a88a69c9 JP |
1254 | if (I_IXON(tty)) |
1255 | start_tty(tty); | |
1256 | if (L_ECHO(tty)) { | |
ec5b1157 | 1257 | echo_char(c, tty); |
a88a69c9 JP |
1258 | process_echoes(tty); |
1259 | } | |
8c985d18 | 1260 | isig(signal, tty); |
1da177e4 LT |
1261 | return; |
1262 | } | |
1263 | } | |
575537b3 JP |
1264 | |
1265 | if (c == '\r') { | |
1266 | if (I_IGNCR(tty)) | |
1267 | return; | |
1268 | if (I_ICRNL(tty)) | |
1269 | c = '\n'; | |
1270 | } else if (c == '\n' && I_INLCR(tty)) | |
1271 | c = '\r'; | |
1272 | ||
53c5ee2c | 1273 | if (ldata->icanon) { |
1da177e4 LT |
1274 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1275 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1276 | eraser(c, tty); | |
a88a69c9 | 1277 | process_echoes(tty); |
1da177e4 LT |
1278 | return; |
1279 | } | |
1280 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1281 | ldata->lnext = 1; |
1da177e4 | 1282 | if (L_ECHO(tty)) { |
57c94121 | 1283 | finish_erasing(ldata); |
1da177e4 | 1284 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1285 | echo_char_raw('^', ldata); |
1286 | echo_char_raw('\b', ldata); | |
a88a69c9 | 1287 | process_echoes(tty); |
1da177e4 LT |
1288 | } |
1289 | } | |
1290 | return; | |
1291 | } | |
1292 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1293 | L_IEXTEN(tty)) { | |
ba2e68ac | 1294 | unsigned long tail = ldata->canon_head; |
1da177e4 | 1295 | |
57c94121 | 1296 | finish_erasing(ldata); |
1da177e4 | 1297 | echo_char(c, tty); |
57c94121 | 1298 | echo_char_raw('\n', ldata); |
ba2e68ac JS |
1299 | while (tail != ldata->read_head) { |
1300 | echo_char(ldata->read_buf[tail], tty); | |
1da177e4 LT |
1301 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); |
1302 | } | |
a88a69c9 | 1303 | process_echoes(tty); |
1da177e4 LT |
1304 | return; |
1305 | } | |
1306 | if (c == '\n') { | |
ba2e68ac | 1307 | if (ldata->read_cnt >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1308 | if (L_ECHO(tty)) |
1309 | process_output('\a', tty); | |
acc71bba JP |
1310 | return; |
1311 | } | |
1312 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
57c94121 | 1313 | echo_char_raw('\n', ldata); |
a88a69c9 | 1314 | process_echoes(tty); |
1da177e4 LT |
1315 | } |
1316 | goto handle_newline; | |
1317 | } | |
1318 | if (c == EOF_CHAR(tty)) { | |
ba2e68ac | 1319 | if (ldata->read_cnt >= N_TTY_BUF_SIZE) |
acc71bba | 1320 | return; |
ba2e68ac | 1321 | if (ldata->canon_head != ldata->read_head) |
4edf1827 | 1322 | set_bit(TTY_PUSH, &tty->flags); |
1da177e4 LT |
1323 | c = __DISABLED_CHAR; |
1324 | goto handle_newline; | |
1325 | } | |
1326 | if ((c == EOL_CHAR(tty)) || | |
1327 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1328 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1329 | ? 1 : 0; | |
ba2e68ac | 1330 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) { |
7e94b1d9 JP |
1331 | if (L_ECHO(tty)) |
1332 | process_output('\a', tty); | |
acc71bba JP |
1333 | return; |
1334 | } | |
1da177e4 LT |
1335 | /* |
1336 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1337 | */ | |
1338 | if (L_ECHO(tty)) { | |
1da177e4 | 1339 | /* Record the column of first canon char. */ |
ba2e68ac | 1340 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1341 | echo_set_canon_col(ldata); |
1da177e4 | 1342 | echo_char(c, tty); |
a88a69c9 | 1343 | process_echoes(tty); |
1da177e4 LT |
1344 | } |
1345 | /* | |
1346 | * XXX does PARMRK doubling happen for | |
1347 | * EOL_CHAR and EOL2_CHAR? | |
1348 | */ | |
acc71bba | 1349 | if (parmrk) |
57c94121 | 1350 | put_tty_queue(c, ldata); |
1da177e4 | 1351 | |
4edf1827 | 1352 | handle_newline: |
98001214 | 1353 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 1354 | set_bit(ldata->read_head, ldata->read_flags); |
57c94121 | 1355 | put_tty_queue_nolock(c, ldata); |
ba2e68ac JS |
1356 | ldata->canon_head = ldata->read_head; |
1357 | ldata->canon_data++; | |
98001214 | 1358 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1359 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1360 | if (waitqueue_active(&tty->read_wait)) | |
1361 | wake_up_interruptible(&tty->read_wait); | |
1362 | return; | |
1363 | } | |
1364 | } | |
4edf1827 | 1365 | |
acc71bba | 1366 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ba2e68ac | 1367 | if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1368 | /* beep if no space */ |
7e94b1d9 JP |
1369 | if (L_ECHO(tty)) |
1370 | process_output('\a', tty); | |
acc71bba JP |
1371 | return; |
1372 | } | |
1373 | if (L_ECHO(tty)) { | |
57c94121 | 1374 | finish_erasing(ldata); |
1da177e4 | 1375 | if (c == '\n') |
57c94121 | 1376 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1377 | else { |
1378 | /* Record the column of first canon char. */ | |
ba2e68ac | 1379 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1380 | echo_set_canon_col(ldata); |
1da177e4 LT |
1381 | echo_char(c, tty); |
1382 | } | |
a88a69c9 | 1383 | process_echoes(tty); |
1da177e4 LT |
1384 | } |
1385 | ||
acc71bba | 1386 | if (parmrk) |
57c94121 | 1387 | put_tty_queue(c, ldata); |
1da177e4 | 1388 | |
57c94121 | 1389 | put_tty_queue(c, ldata); |
4edf1827 | 1390 | } |
1da177e4 | 1391 | |
1da177e4 LT |
1392 | |
1393 | /** | |
1394 | * n_tty_write_wakeup - asynchronous I/O notifier | |
1395 | * @tty: tty device | |
1396 | * | |
1397 | * Required for the ptys, serial driver etc. since processes | |
1398 | * that attach themselves to the master and rely on ASYNC | |
1399 | * IO must be woken up | |
1400 | */ | |
1401 | ||
1402 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
1403 | { | |
ff8cb0fd | 1404 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) |
1da177e4 | 1405 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); |
1da177e4 LT |
1406 | } |
1407 | ||
1408 | /** | |
1409 | * n_tty_receive_buf - data receive | |
1410 | * @tty: terminal device | |
1411 | * @cp: buffer | |
1412 | * @fp: flag buffer | |
1413 | * @count: characters | |
1414 | * | |
1415 | * Called by the terminal driver when a block of characters has | |
1416 | * been received. This function must be called from soft contexts | |
1417 | * not from interrupt context. The driver is responsible for making | |
1418 | * calls one at a time and in order (or using flush_to_ldisc) | |
1419 | */ | |
4edf1827 | 1420 | |
24a89d1c PH |
1421 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1422 | char *fp, int count) | |
1da177e4 | 1423 | { |
53c5ee2c | 1424 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1425 | const unsigned char *p; |
1426 | char *f, flags = TTY_NORMAL; | |
1427 | int i; | |
1428 | char buf[64]; | |
1429 | unsigned long cpuflags; | |
1430 | ||
53c5ee2c | 1431 | if (ldata->real_raw) { |
98001214 | 1432 | raw_spin_lock_irqsave(&ldata->read_lock, cpuflags); |
ba2e68ac JS |
1433 | i = min(N_TTY_BUF_SIZE - ldata->read_cnt, |
1434 | N_TTY_BUF_SIZE - ldata->read_head); | |
1da177e4 | 1435 | i = min(count, i); |
ba2e68ac JS |
1436 | memcpy(ldata->read_buf + ldata->read_head, cp, i); |
1437 | ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1438 | ldata->read_cnt += i; | |
1da177e4 LT |
1439 | cp += i; |
1440 | count -= i; | |
1441 | ||
ba2e68ac JS |
1442 | i = min(N_TTY_BUF_SIZE - ldata->read_cnt, |
1443 | N_TTY_BUF_SIZE - ldata->read_head); | |
1da177e4 | 1444 | i = min(count, i); |
ba2e68ac JS |
1445 | memcpy(ldata->read_buf + ldata->read_head, cp, i); |
1446 | ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1); | |
1447 | ldata->read_cnt += i; | |
98001214 | 1448 | raw_spin_unlock_irqrestore(&ldata->read_lock, cpuflags); |
1da177e4 | 1449 | } else { |
4edf1827 | 1450 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1451 | if (f) |
1452 | flags = *f++; | |
1453 | switch (flags) { | |
1454 | case TTY_NORMAL: | |
1455 | n_tty_receive_char(tty, *p); | |
1456 | break; | |
1457 | case TTY_BREAK: | |
1458 | n_tty_receive_break(tty); | |
1459 | break; | |
1460 | case TTY_PARITY: | |
1461 | case TTY_FRAME: | |
1462 | n_tty_receive_parity_error(tty, *p); | |
1463 | break; | |
1464 | case TTY_OVERRUN: | |
1465 | n_tty_receive_overrun(tty); | |
1466 | break; | |
1467 | default: | |
4edf1827 | 1468 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1469 | tty_name(tty, buf), flags); |
1470 | break; | |
1471 | } | |
1472 | } | |
f34d7a5b AC |
1473 | if (tty->ops->flush_chars) |
1474 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1475 | } |
1476 | ||
f6c8dbe6 | 1477 | if ((!ldata->icanon && (ldata->read_cnt >= ldata->minimum_to_wake)) || |
26df6d13 | 1478 | L_EXTPROC(tty)) { |
1da177e4 LT |
1479 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1480 | if (waitqueue_active(&tty->read_wait)) | |
1481 | wake_up_interruptible(&tty->read_wait); | |
1482 | } | |
1483 | ||
1484 | /* | |
1485 | * Check the remaining room for the input canonicalization | |
1486 | * mode. We don't want to throttle the driver if we're in | |
1487 | * canonical mode and don't have a newline yet! | |
1488 | */ | |
e91e52e4 PH |
1489 | while (1) { |
1490 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
24a89d1c | 1491 | if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) |
e91e52e4 PH |
1492 | break; |
1493 | if (!tty_throttle_safe(tty)) | |
1494 | break; | |
1495 | } | |
1496 | __tty_set_flow_change(tty, 0); | |
1da177e4 LT |
1497 | } |
1498 | ||
24a89d1c PH |
1499 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1500 | char *fp, int count) | |
1501 | { | |
1502 | __receive_buf(tty, cp, fp, count); | |
1503 | } | |
1504 | ||
1505 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1506 | char *fp, int count) | |
1507 | { | |
1508 | struct n_tty_data *ldata = tty->disc_data; | |
1509 | int room; | |
1510 | ||
1511 | tty->receive_room = room = receive_room(tty); | |
1512 | if (!room) | |
1513 | ldata->no_room = 1; | |
1514 | count = min(count, room); | |
1515 | if (count) | |
1516 | __receive_buf(tty, cp, fp, count); | |
1517 | ||
1518 | return count; | |
1519 | } | |
1520 | ||
1da177e4 LT |
1521 | int is_ignored(int sig) |
1522 | { | |
1523 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1524 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1525 | } |
1526 | ||
1527 | /** | |
1528 | * n_tty_set_termios - termios data changed | |
1529 | * @tty: terminal | |
1530 | * @old: previous data | |
1531 | * | |
1532 | * Called by the tty layer when the user changes termios flags so | |
1533 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1534 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1535 | * guaranteed that this function will not be re-entered or in progress |
1536 | * when the ldisc is closed. | |
17b82060 AC |
1537 | * |
1538 | * Locking: Caller holds tty->termios_mutex | |
1da177e4 | 1539 | */ |
4edf1827 AC |
1540 | |
1541 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1542 | { |
53c5ee2c | 1543 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1544 | int canon_change = 1; |
47afa7a5 AC |
1545 | |
1546 | if (old) | |
adc8d746 | 1547 | canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON; |
47afa7a5 | 1548 | if (canon_change) { |
3fe780b3 | 1549 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
ba2e68ac JS |
1550 | ldata->canon_head = ldata->read_tail; |
1551 | ldata->canon_data = 0; | |
53c5ee2c | 1552 | ldata->erasing = 0; |
47afa7a5 AC |
1553 | } |
1554 | ||
ba2e68ac | 1555 | if (canon_change && !L_ICANON(tty) && ldata->read_cnt) |
47afa7a5 | 1556 | wake_up_interruptible(&tty->read_wait); |
4edf1827 | 1557 | |
53c5ee2c | 1558 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1559 | |
1da177e4 LT |
1560 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1561 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1562 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1563 | I_PARMRK(tty)) { | |
3fe780b3 | 1564 | bitmap_zero(ldata->process_char_map, 256); |
1da177e4 LT |
1565 | |
1566 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
3fe780b3 | 1567 | set_bit('\r', ldata->process_char_map); |
1da177e4 | 1568 | if (I_INLCR(tty)) |
3fe780b3 | 1569 | set_bit('\n', ldata->process_char_map); |
1da177e4 LT |
1570 | |
1571 | if (L_ICANON(tty)) { | |
3fe780b3 JS |
1572 | set_bit(ERASE_CHAR(tty), ldata->process_char_map); |
1573 | set_bit(KILL_CHAR(tty), ldata->process_char_map); | |
1574 | set_bit(EOF_CHAR(tty), ldata->process_char_map); | |
1575 | set_bit('\n', ldata->process_char_map); | |
1576 | set_bit(EOL_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1577 | if (L_IEXTEN(tty)) { |
1578 | set_bit(WERASE_CHAR(tty), | |
3fe780b3 | 1579 | ldata->process_char_map); |
1da177e4 | 1580 | set_bit(LNEXT_CHAR(tty), |
3fe780b3 | 1581 | ldata->process_char_map); |
1da177e4 | 1582 | set_bit(EOL2_CHAR(tty), |
3fe780b3 | 1583 | ldata->process_char_map); |
1da177e4 LT |
1584 | if (L_ECHO(tty)) |
1585 | set_bit(REPRINT_CHAR(tty), | |
3fe780b3 | 1586 | ldata->process_char_map); |
1da177e4 LT |
1587 | } |
1588 | } | |
1589 | if (I_IXON(tty)) { | |
3fe780b3 JS |
1590 | set_bit(START_CHAR(tty), ldata->process_char_map); |
1591 | set_bit(STOP_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1592 | } |
1593 | if (L_ISIG(tty)) { | |
3fe780b3 JS |
1594 | set_bit(INTR_CHAR(tty), ldata->process_char_map); |
1595 | set_bit(QUIT_CHAR(tty), ldata->process_char_map); | |
1596 | set_bit(SUSP_CHAR(tty), ldata->process_char_map); | |
1da177e4 | 1597 | } |
3fe780b3 | 1598 | clear_bit(__DISABLED_CHAR, ldata->process_char_map); |
53c5ee2c JS |
1599 | ldata->raw = 0; |
1600 | ldata->real_raw = 0; | |
1da177e4 | 1601 | } else { |
53c5ee2c | 1602 | ldata->raw = 1; |
1da177e4 LT |
1603 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1604 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1605 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1606 | ldata->real_raw = 1; |
1da177e4 | 1607 | else |
53c5ee2c | 1608 | ldata->real_raw = 0; |
1da177e4 | 1609 | } |
55db4c64 | 1610 | n_tty_set_room(tty); |
dab73b4e WY |
1611 | /* |
1612 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1613 | * been stopped by STOP_CHAR(tty) before it. | |
1614 | */ | |
1615 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { | |
1616 | start_tty(tty); | |
1617 | } | |
1618 | ||
f34d7a5b AC |
1619 | /* The termios change make the tty ready for I/O */ |
1620 | wake_up_interruptible(&tty->write_wait); | |
1621 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1622 | } |
1623 | ||
1624 | /** | |
1625 | * n_tty_close - close the ldisc for this tty | |
1626 | * @tty: device | |
1627 | * | |
4edf1827 AC |
1628 | * Called from the terminal layer when this line discipline is |
1629 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1630 | * discipline change. The function will not be called while other |
1631 | * ldisc methods are in progress. | |
1632 | */ | |
4edf1827 | 1633 | |
1da177e4 LT |
1634 | static void n_tty_close(struct tty_struct *tty) |
1635 | { | |
70ece7a7 JS |
1636 | struct n_tty_data *ldata = tty->disc_data; |
1637 | ||
79901317 PH |
1638 | if (tty->link) |
1639 | n_tty_packet_mode_flush(tty); | |
1640 | ||
ba2e68ac JS |
1641 | kfree(ldata->read_buf); |
1642 | kfree(ldata->echo_buf); | |
70ece7a7 | 1643 | kfree(ldata); |
70ece7a7 | 1644 | tty->disc_data = NULL; |
1da177e4 LT |
1645 | } |
1646 | ||
1647 | /** | |
1648 | * n_tty_open - open an ldisc | |
1649 | * @tty: terminal to open | |
1650 | * | |
4edf1827 | 1651 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1652 | * terminal device. Can sleep. Called serialized so that no |
1653 | * other events will occur in parallel. No further open will occur | |
1654 | * until a close. | |
1655 | */ | |
1656 | ||
1657 | static int n_tty_open(struct tty_struct *tty) | |
1658 | { | |
70ece7a7 JS |
1659 | struct n_tty_data *ldata; |
1660 | ||
1661 | ldata = kzalloc(sizeof(*ldata), GFP_KERNEL); | |
1662 | if (!ldata) | |
1663 | goto err; | |
1664 | ||
53c5ee2c | 1665 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1666 | mutex_init(&ldata->atomic_read_lock); |
1667 | mutex_init(&ldata->output_lock); | |
1668 | mutex_init(&ldata->echo_lock); | |
98001214 | 1669 | raw_spin_lock_init(&ldata->read_lock); |
53c5ee2c | 1670 | |
a88a69c9 | 1671 | /* These are ugly. Currently a malloc failure here can panic */ |
ba2e68ac JS |
1672 | ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1673 | ldata->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); | |
1674 | if (!ldata->read_buf || !ldata->echo_buf) | |
b91939f5 | 1675 | goto err_free_bufs; |
0b4068a1 | 1676 | |
70ece7a7 | 1677 | tty->disc_data = ldata; |
b66f4fa5 | 1678 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1679 | ldata->column = 0; |
f6c8dbe6 | 1680 | ldata->minimum_to_wake = 1; |
1da177e4 | 1681 | tty->closing = 0; |
b66f4fa5 PH |
1682 | /* indicate buffer work may resume */ |
1683 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1684 | n_tty_set_termios(tty, NULL); | |
1685 | tty_unthrottle(tty); | |
70ece7a7 | 1686 | |
1da177e4 | 1687 | return 0; |
b91939f5 | 1688 | err_free_bufs: |
ba2e68ac JS |
1689 | kfree(ldata->read_buf); |
1690 | kfree(ldata->echo_buf); | |
70ece7a7 JS |
1691 | kfree(ldata); |
1692 | err: | |
b91939f5 | 1693 | return -ENOMEM; |
1da177e4 LT |
1694 | } |
1695 | ||
1696 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1697 | { | |
53c5ee2c JS |
1698 | struct n_tty_data *ldata = tty->disc_data; |
1699 | ||
e043e42b | 1700 | tty_flush_to_ldisc(tty); |
53c5ee2c | 1701 | if (ldata->icanon && !L_EXTPROC(tty)) { |
ba2e68ac | 1702 | if (ldata->canon_data) |
1da177e4 | 1703 | return 1; |
ba2e68ac | 1704 | } else if (ldata->read_cnt >= (amt ? amt : 1)) |
1da177e4 LT |
1705 | return 1; |
1706 | ||
1707 | return 0; | |
1708 | } | |
1709 | ||
1710 | /** | |
bbd20759 | 1711 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1712 | * @tty: terminal device |
1713 | * @b: user data | |
1714 | * @nr: size of data | |
1715 | * | |
11a96d18 | 1716 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1717 | * ICANON is off; it copies characters straight from the tty queue to |
1718 | * user space directly. It can be profitably called twice; once to | |
1719 | * drain the space from the tail pointer to the (physical) end of the | |
1720 | * buffer, and once to drain the space from the (physical) beginning of | |
1721 | * the buffer to head pointer. | |
1722 | * | |
bddc7152 | 1723 | * Called under the ldata->atomic_read_lock sem |
1da177e4 LT |
1724 | * |
1725 | */ | |
4edf1827 | 1726 | |
33f0f88f | 1727 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1728 | unsigned char __user **b, |
1729 | size_t *nr) | |
1730 | ||
1731 | { | |
53c5ee2c | 1732 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1733 | int retval; |
1734 | size_t n; | |
1735 | unsigned long flags; | |
3fa10cc8 | 1736 | bool is_eof; |
1da177e4 LT |
1737 | |
1738 | retval = 0; | |
98001214 | 1739 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac | 1740 | n = min(ldata->read_cnt, N_TTY_BUF_SIZE - ldata->read_tail); |
1da177e4 | 1741 | n = min(*nr, n); |
98001214 | 1742 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 | 1743 | if (n) { |
ba2e68ac | 1744 | retval = copy_to_user(*b, &ldata->read_buf[ldata->read_tail], n); |
1da177e4 | 1745 | n -= retval; |
3fa10cc8 | 1746 | is_eof = n == 1 && |
ba2e68ac JS |
1747 | ldata->read_buf[ldata->read_tail] == EOF_CHAR(tty); |
1748 | tty_audit_add_data(tty, &ldata->read_buf[ldata->read_tail], n, | |
53c5ee2c | 1749 | ldata->icanon); |
98001214 | 1750 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
ba2e68ac JS |
1751 | ldata->read_tail = (ldata->read_tail + n) & (N_TTY_BUF_SIZE-1); |
1752 | ldata->read_cnt -= n; | |
26df6d13 | 1753 | /* Turn single EOF into zero-length read */ |
ba2e68ac | 1754 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !ldata->read_cnt) |
3fa10cc8 | 1755 | n = 0; |
98001214 | 1756 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
1da177e4 LT |
1757 | *b += n; |
1758 | *nr -= n; | |
1759 | } | |
1760 | return retval; | |
1761 | } | |
1762 | ||
88bb0de3 | 1763 | /** |
32f13521 | 1764 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1765 | * @tty: terminal device |
1766 | * @b: user data | |
1767 | * @nr: size of data | |
1768 | * | |
1769 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1770 | * it copies one line of input up to and including the line-delimiting |
1771 | * character into the user-space buffer. | |
88bb0de3 PH |
1772 | * |
1773 | * Called under the atomic_read_lock mutex | |
1774 | */ | |
1775 | ||
32f13521 PH |
1776 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
1777 | unsigned char __user **b, | |
1778 | size_t *nr) | |
88bb0de3 PH |
1779 | { |
1780 | struct n_tty_data *ldata = tty->disc_data; | |
1781 | unsigned long flags; | |
32f13521 PH |
1782 | size_t n, size, more, c; |
1783 | unsigned long eol; | |
1784 | int ret, tail, found = 0; | |
88bb0de3 PH |
1785 | |
1786 | /* N.B. avoid overrun if nr == 0 */ | |
32f13521 | 1787 | |
88bb0de3 | 1788 | raw_spin_lock_irqsave(&ldata->read_lock, flags); |
32f13521 PH |
1789 | |
1790 | n = min_t(size_t, *nr, ldata->read_cnt); | |
1791 | if (!n) { | |
88bb0de3 | 1792 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); |
32f13521 PH |
1793 | return 0; |
1794 | } | |
88bb0de3 | 1795 | |
32f13521 PH |
1796 | tail = ldata->read_tail; |
1797 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); | |
1798 | ||
1799 | n_tty_trace("%s: nr:%zu tail:%d n:%zu size:%zu\n", | |
1800 | __func__, *nr, tail, n, size); | |
1801 | ||
1802 | eol = find_next_bit(ldata->read_flags, size, tail); | |
1803 | more = n - (size - tail); | |
1804 | if (eol == N_TTY_BUF_SIZE && more) { | |
1805 | /* scan wrapped without finding set bit */ | |
1806 | eol = find_next_bit(ldata->read_flags, more, 0); | |
1807 | if (eol != more) | |
1808 | found = 1; | |
1809 | } else if (eol != size) | |
1810 | found = 1; | |
1811 | ||
1812 | size = N_TTY_BUF_SIZE - tail; | |
1813 | n = (found + eol + size) & (N_TTY_BUF_SIZE - 1); | |
1814 | c = n; | |
1815 | ||
1816 | if (found && ldata->read_buf[eol] == __DISABLED_CHAR) | |
1817 | n--; | |
1818 | ||
1819 | n_tty_trace("%s: eol:%lu found:%d n:%zu c:%zu size:%zu more:%zu\n", | |
1820 | __func__, eol, found, n, c, size, more); | |
1821 | ||
1822 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); | |
1823 | ||
1824 | if (n > size) { | |
1825 | ret = copy_to_user(*b, &ldata->read_buf[tail], size); | |
1826 | if (ret) | |
1827 | return -EFAULT; | |
1828 | ret = copy_to_user(*b + size, ldata->read_buf, n - size); | |
1829 | } else | |
1830 | ret = copy_to_user(*b, &ldata->read_buf[tail], n); | |
1831 | ||
1832 | if (ret) | |
1833 | return -EFAULT; | |
1834 | *b += n; | |
1835 | *nr -= n; | |
1836 | ||
1837 | raw_spin_lock_irqsave(&ldata->read_lock, flags); | |
1838 | ldata->read_tail = (ldata->read_tail + c) & (N_TTY_BUF_SIZE - 1); | |
1839 | ldata->read_cnt -= c; | |
1840 | if (found) { | |
1841 | __clear_bit(eol, ldata->read_flags); | |
1842 | /* this test should be redundant: | |
1843 | * we shouldn't be reading data if | |
1844 | * canon_data is 0 | |
1845 | */ | |
1846 | if (--ldata->canon_data < 0) | |
1847 | ldata->canon_data = 0; | |
88bb0de3 PH |
1848 | } |
1849 | raw_spin_unlock_irqrestore(&ldata->read_lock, flags); | |
1850 | ||
32f13521 PH |
1851 | if (found) |
1852 | tty_audit_push(tty); | |
88bb0de3 PH |
1853 | return 0; |
1854 | } | |
1855 | ||
cc4191dc | 1856 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1857 | size_t, loff_t *); |
1da177e4 LT |
1858 | |
1859 | /** | |
1860 | * job_control - check job control | |
1861 | * @tty: tty | |
1862 | * @file: file handle | |
1863 | * | |
1864 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1865 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1866 | * error code if action should be taken. |
04f378b1 | 1867 | * |
01a5e440 PH |
1868 | * Locking: redirected write test is safe |
1869 | * current->signal->tty check is safe | |
1870 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 1871 | */ |
4edf1827 | 1872 | |
1da177e4 LT |
1873 | static int job_control(struct tty_struct *tty, struct file *file) |
1874 | { | |
1875 | /* Job control check -- must be done at start and after | |
1876 | every sleep (POSIX.1 7.1.1.4). */ | |
1877 | /* NOTE: not yet done after every sleep pending a thorough | |
1878 | check of the logic of this change. -- jlc */ | |
1879 | /* don't stop on /dev/console */ | |
01a5e440 PH |
1880 | if (file->f_op->write == redirected_tty_write || |
1881 | current->signal->tty != tty) | |
1882 | return 0; | |
1883 | ||
1884 | spin_lock_irq(&tty->ctrl_lock); | |
1885 | if (!tty->pgrp) | |
1886 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
1887 | else if (task_pgrp(current) != tty->pgrp) { | |
1888 | spin_unlock_irq(&tty->ctrl_lock); | |
1889 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
1890 | return -EIO; | |
1891 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
1892 | set_thread_flag(TIF_SIGPENDING); | |
1893 | return -ERESTARTSYS; | |
1da177e4 | 1894 | } |
01a5e440 | 1895 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
1896 | return 0; |
1897 | } | |
4edf1827 | 1898 | |
1da177e4 LT |
1899 | |
1900 | /** | |
11a96d18 | 1901 | * n_tty_read - read function for tty |
1da177e4 LT |
1902 | * @tty: tty device |
1903 | * @file: file object | |
1904 | * @buf: userspace buffer pointer | |
1905 | * @nr: size of I/O | |
1906 | * | |
1907 | * Perform reads for the line discipline. We are guaranteed that the | |
1908 | * line discipline will not be closed under us but we may get multiple | |
1909 | * parallel readers and must handle this ourselves. We may also get | |
1910 | * a hangup. Always called in user context, may sleep. | |
1911 | * | |
1912 | * This code must be sure never to sleep through a hangup. | |
1913 | */ | |
4edf1827 | 1914 | |
11a96d18 | 1915 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1916 | unsigned char __user *buf, size_t nr) |
1917 | { | |
53c5ee2c | 1918 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1919 | unsigned char __user *b = buf; |
1920 | DECLARE_WAITQUEUE(wait, current); | |
1921 | int c; | |
1922 | int minimum, time; | |
1923 | ssize_t retval = 0; | |
1924 | ssize_t size; | |
1925 | long timeout; | |
1926 | unsigned long flags; | |
04f378b1 | 1927 | int packet; |
1da177e4 LT |
1928 | |
1929 | do_it_again: | |
1da177e4 | 1930 | c = job_control(tty, file); |
4edf1827 | 1931 | if (c < 0) |
1da177e4 | 1932 | return c; |
4edf1827 | 1933 | |
1da177e4 LT |
1934 | minimum = time = 0; |
1935 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 1936 | if (!ldata->icanon) { |
1da177e4 LT |
1937 | minimum = MIN_CHAR(tty); |
1938 | if (minimum) { | |
a6e54319 | 1939 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 1940 | if (time) |
f6c8dbe6 | 1941 | ldata->minimum_to_wake = 1; |
1da177e4 | 1942 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
1943 | (ldata->minimum_to_wake > minimum)) |
1944 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 1945 | } else { |
a6e54319 | 1946 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 1947 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
1948 | } |
1949 | } | |
1950 | ||
1951 | /* | |
1952 | * Internal serialization of reads. | |
1953 | */ | |
1954 | if (file->f_flags & O_NONBLOCK) { | |
bddc7152 | 1955 | if (!mutex_trylock(&ldata->atomic_read_lock)) |
1da177e4 | 1956 | return -EAGAIN; |
4edf1827 | 1957 | } else { |
bddc7152 | 1958 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) |
1da177e4 LT |
1959 | return -ERESTARTSYS; |
1960 | } | |
04f378b1 | 1961 | packet = tty->packet; |
1da177e4 LT |
1962 | |
1963 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
1964 | while (nr) { |
1965 | /* First test for status change. */ | |
04f378b1 | 1966 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
1967 | unsigned char cs; |
1968 | if (b != buf) | |
1969 | break; | |
04f378b1 | 1970 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
1971 | cs = tty->link->ctrl_status; |
1972 | tty->link->ctrl_status = 0; | |
04f378b1 | 1973 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 1974 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
1975 | retval = -EFAULT; |
1976 | b--; | |
1977 | break; | |
1978 | } | |
1979 | nr--; | |
1980 | break; | |
1981 | } | |
1982 | /* This statement must be first before checking for input | |
1983 | so that any interrupt will set the state back to | |
1984 | TASK_RUNNING. */ | |
1985 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 1986 | |
f6c8dbe6 | 1987 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 1988 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 1989 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 1990 | |
1da177e4 LT |
1991 | if (!input_available_p(tty, 0)) { |
1992 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
1993 | retval = -EIO; | |
1994 | break; | |
1995 | } | |
1996 | if (tty_hung_up_p(file)) | |
1997 | break; | |
1998 | if (!timeout) | |
1999 | break; | |
2000 | if (file->f_flags & O_NONBLOCK) { | |
2001 | retval = -EAGAIN; | |
2002 | break; | |
2003 | } | |
2004 | if (signal_pending(current)) { | |
2005 | retval = -ERESTARTSYS; | |
2006 | break; | |
2007 | } | |
55db4c64 | 2008 | n_tty_set_room(tty); |
1da177e4 | 2009 | timeout = schedule_timeout(timeout); |
1da177e4 LT |
2010 | continue; |
2011 | } | |
2012 | __set_current_state(TASK_RUNNING); | |
2013 | ||
2014 | /* Deal with packet mode. */ | |
04f378b1 | 2015 | if (packet && b == buf) { |
522ed776 | 2016 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
2017 | retval = -EFAULT; |
2018 | b--; | |
2019 | break; | |
2020 | } | |
2021 | nr--; | |
2022 | } | |
2023 | ||
53c5ee2c | 2024 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2025 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
1da177e4 LT |
2026 | if (retval) |
2027 | break; | |
2028 | } else { | |
2029 | int uncopied; | |
04f378b1 AC |
2030 | /* The copy function takes the read lock and handles |
2031 | locking internally for this case */ | |
1da177e4 LT |
2032 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2033 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2034 | if (uncopied) { | |
2035 | retval = -EFAULT; | |
2036 | break; | |
2037 | } | |
2038 | } | |
2039 | ||
2040 | /* If there is enough space in the read buffer now, let the | |
a19d0c6a | 2041 | * low-level driver know. We use chars_in_buffer() to |
1da177e4 LT |
2042 | * check the buffer, as it now knows about canonical mode. |
2043 | * Otherwise, if the driver is throttled and the line is | |
2044 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
2045 | * we won't get any more characters. | |
2046 | */ | |
e91e52e4 PH |
2047 | while (1) { |
2048 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
a19d0c6a | 2049 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) |
e91e52e4 PH |
2050 | break; |
2051 | if (!tty->count) | |
2052 | break; | |
55db4c64 | 2053 | n_tty_set_room(tty); |
e91e52e4 PH |
2054 | if (!tty_unthrottle_safe(tty)) |
2055 | break; | |
55db4c64 | 2056 | } |
e91e52e4 | 2057 | __tty_set_flow_change(tty, 0); |
1da177e4 LT |
2058 | |
2059 | if (b - buf >= minimum) | |
2060 | break; | |
2061 | if (time) | |
2062 | timeout = time; | |
2063 | } | |
bddc7152 | 2064 | mutex_unlock(&ldata->atomic_read_lock); |
1da177e4 LT |
2065 | remove_wait_queue(&tty->read_wait, &wait); |
2066 | ||
2067 | if (!waitqueue_active(&tty->read_wait)) | |
f6c8dbe6 | 2068 | ldata->minimum_to_wake = minimum; |
1da177e4 LT |
2069 | |
2070 | __set_current_state(TASK_RUNNING); | |
2071 | size = b - buf; | |
2072 | if (size) { | |
2073 | retval = size; | |
2074 | if (nr) | |
4edf1827 | 2075 | clear_bit(TTY_PUSH, &tty->flags); |
1da177e4 | 2076 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) |
bbd20759 | 2077 | goto do_it_again; |
1da177e4 | 2078 | |
55db4c64 | 2079 | n_tty_set_room(tty); |
1da177e4 LT |
2080 | return retval; |
2081 | } | |
2082 | ||
2083 | /** | |
11a96d18 | 2084 | * n_tty_write - write function for tty |
1da177e4 LT |
2085 | * @tty: tty device |
2086 | * @file: file object | |
2087 | * @buf: userspace buffer pointer | |
2088 | * @nr: size of I/O | |
2089 | * | |
a88a69c9 | 2090 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2091 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2092 | * and other such events. Since the receive code will echo characters, |
2093 | * thus calling driver write methods, the output_lock is used in | |
2094 | * the output processing functions called here as well as in the | |
2095 | * echo processing function to protect the column state and space | |
2096 | * left in the buffer. | |
1da177e4 LT |
2097 | * |
2098 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2099 | * |
2100 | * Locking: output_lock to protect column state and space left | |
2101 | * (note that the process_output*() functions take this | |
2102 | * lock themselves) | |
1da177e4 | 2103 | */ |
4edf1827 | 2104 | |
11a96d18 | 2105 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2106 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2107 | { |
2108 | const unsigned char *b = buf; | |
2109 | DECLARE_WAITQUEUE(wait, current); | |
2110 | int c; | |
2111 | ssize_t retval = 0; | |
2112 | ||
2113 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2114 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2115 | retval = tty_check_change(tty); | |
2116 | if (retval) | |
2117 | return retval; | |
2118 | } | |
2119 | ||
a88a69c9 JP |
2120 | /* Write out any echoed characters that are still pending */ |
2121 | process_echoes(tty); | |
300a6204 | 2122 | |
1da177e4 LT |
2123 | add_wait_queue(&tty->write_wait, &wait); |
2124 | while (1) { | |
2125 | set_current_state(TASK_INTERRUPTIBLE); | |
2126 | if (signal_pending(current)) { | |
2127 | retval = -ERESTARTSYS; | |
2128 | break; | |
2129 | } | |
2130 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2131 | retval = -EIO; | |
2132 | break; | |
2133 | } | |
582f5590 | 2134 | if (O_OPOST(tty)) { |
1da177e4 | 2135 | while (nr > 0) { |
a88a69c9 | 2136 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2137 | if (num < 0) { |
2138 | if (num == -EAGAIN) | |
2139 | break; | |
2140 | retval = num; | |
2141 | goto break_out; | |
2142 | } | |
2143 | b += num; | |
2144 | nr -= num; | |
2145 | if (nr == 0) | |
2146 | break; | |
2147 | c = *b; | |
a88a69c9 | 2148 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2149 | break; |
2150 | b++; nr--; | |
2151 | } | |
f34d7a5b AC |
2152 | if (tty->ops->flush_chars) |
2153 | tty->ops->flush_chars(tty); | |
1da177e4 | 2154 | } else { |
d6afe27b | 2155 | while (nr > 0) { |
f34d7a5b | 2156 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
2157 | if (c < 0) { |
2158 | retval = c; | |
2159 | goto break_out; | |
2160 | } | |
2161 | if (!c) | |
2162 | break; | |
2163 | b += c; | |
2164 | nr -= c; | |
1da177e4 | 2165 | } |
1da177e4 LT |
2166 | } |
2167 | if (!nr) | |
2168 | break; | |
2169 | if (file->f_flags & O_NONBLOCK) { | |
2170 | retval = -EAGAIN; | |
2171 | break; | |
2172 | } | |
2173 | schedule(); | |
2174 | } | |
2175 | break_out: | |
2176 | __set_current_state(TASK_RUNNING); | |
2177 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2178 | if (b - buf != nr && tty->fasync) |
2179 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
1da177e4 LT |
2180 | return (b - buf) ? b - buf : retval; |
2181 | } | |
2182 | ||
2183 | /** | |
11a96d18 | 2184 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2185 | * @tty: terminal device |
2186 | * @file: file accessing it | |
2187 | * @wait: poll table | |
2188 | * | |
2189 | * Called when the line discipline is asked to poll() for data or | |
2190 | * for special events. This code is not serialized with respect to | |
2191 | * other events save open/close. | |
2192 | * | |
2193 | * This code must be sure never to sleep through a hangup. | |
2194 | * Called without the kernel lock held - fine | |
1da177e4 | 2195 | */ |
4edf1827 | 2196 | |
11a96d18 | 2197 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2198 | poll_table *wait) |
1da177e4 | 2199 | { |
f6c8dbe6 | 2200 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2201 | unsigned int mask = 0; |
2202 | ||
2203 | poll_wait(file, &tty->read_wait, wait); | |
2204 | poll_wait(file, &tty->write_wait, wait); | |
2205 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2206 | mask |= POLLIN | POLLRDNORM; | |
2207 | if (tty->packet && tty->link->ctrl_status) | |
2208 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2209 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2210 | mask |= POLLHUP; | |
2211 | if (tty_hung_up_p(file)) | |
2212 | mask |= POLLHUP; | |
2213 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2214 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2215 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2216 | else |
f6c8dbe6 | 2217 | ldata->minimum_to_wake = 1; |
1da177e4 | 2218 | } |
f34d7a5b AC |
2219 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2220 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2221 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2222 | mask |= POLLOUT | POLLWRNORM; |
2223 | return mask; | |
2224 | } | |
2225 | ||
57c94121 | 2226 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 AC |
2227 | { |
2228 | int nr, head, tail; | |
2229 | ||
ba2e68ac | 2230 | if (!ldata->canon_data) |
47afa7a5 | 2231 | return 0; |
ba2e68ac JS |
2232 | head = ldata->canon_head; |
2233 | tail = ldata->read_tail; | |
47afa7a5 AC |
2234 | nr = (head - tail) & (N_TTY_BUF_SIZE-1); |
2235 | /* Skip EOF-chars.. */ | |
2236 | while (head != tail) { | |
3fe780b3 | 2237 | if (test_bit(tail, ldata->read_flags) && |
ba2e68ac | 2238 | ldata->read_buf[tail] == __DISABLED_CHAR) |
47afa7a5 AC |
2239 | nr--; |
2240 | tail = (tail+1) & (N_TTY_BUF_SIZE-1); | |
2241 | } | |
2242 | return nr; | |
2243 | } | |
2244 | ||
2245 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2246 | unsigned int cmd, unsigned long arg) | |
2247 | { | |
ba2e68ac | 2248 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2249 | int retval; |
2250 | ||
2251 | switch (cmd) { | |
2252 | case TIOCOUTQ: | |
2253 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2254 | case TIOCINQ: | |
17b82060 | 2255 | /* FIXME: Locking */ |
ba2e68ac | 2256 | retval = ldata->read_cnt; |
47afa7a5 | 2257 | if (L_ICANON(tty)) |
57c94121 | 2258 | retval = inq_canon(ldata); |
47afa7a5 AC |
2259 | return put_user(retval, (unsigned int __user *) arg); |
2260 | default: | |
2261 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2262 | } | |
2263 | } | |
2264 | ||
f6c8dbe6 PH |
2265 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2266 | { | |
2267 | struct n_tty_data *ldata = tty->disc_data; | |
2268 | ||
2269 | if (!waitqueue_active(&tty->read_wait)) { | |
2270 | if (on) | |
2271 | ldata->minimum_to_wake = 1; | |
2272 | else if (!tty->fasync) | |
2273 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2274 | } | |
2275 | } | |
2276 | ||
a352def2 | 2277 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2278 | .magic = TTY_LDISC_MAGIC, |
2279 | .name = "n_tty", | |
2280 | .open = n_tty_open, | |
2281 | .close = n_tty_close, | |
2282 | .flush_buffer = n_tty_flush_buffer, | |
2283 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2284 | .read = n_tty_read, |
2285 | .write = n_tty_write, | |
e10cc1df PF |
2286 | .ioctl = n_tty_ioctl, |
2287 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2288 | .poll = n_tty_poll, |
e10cc1df | 2289 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2290 | .write_wakeup = n_tty_write_wakeup, |
2291 | .fasync = n_tty_fasync, | |
24a89d1c | 2292 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2293 | }; |
572b9adb RG |
2294 | |
2295 | /** | |
2296 | * n_tty_inherit_ops - inherit N_TTY methods | |
2297 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2298 | * | |
593fb1ae | 2299 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2300 | * methods. |
2301 | */ | |
2302 | ||
2303 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2304 | { | |
2305 | *ops = tty_ldisc_N_TTY; | |
2306 | ops->owner = NULL; | |
2307 | ops->refcount = ops->flags = 0; | |
2308 | } | |
2309 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |