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