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 { |
fb7aa03d PH |
85 | /* producer-published */ |
86 | size_t read_head; | |
87 | size_t canon_head; | |
88 | DECLARE_BITMAP(process_char_map, 256); | |
89 | ||
90 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c JS |
91 | unsigned long overrun_time; |
92 | int num_overrun; | |
93 | ||
24a89d1c PH |
94 | /* non-atomic */ |
95 | bool no_room; | |
96 | ||
fb7aa03d | 97 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c JS |
98 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
99 | unsigned char echo_overrun:1; | |
3fe780b3 | 100 | |
fb7aa03d PH |
101 | /* shared by producer and consumer */ |
102 | char *read_buf; | |
3fe780b3 | 103 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
ba2e68ac | 104 | |
f6c8dbe6 | 105 | int minimum_to_wake; |
ba2e68ac | 106 | |
fb7aa03d PH |
107 | /* consumer-published */ |
108 | size_t read_tail; | |
109 | ||
110 | /* protected by echo_lock */ | |
ba2e68ac JS |
111 | unsigned char *echo_buf; |
112 | unsigned int echo_pos; | |
113 | unsigned int echo_cnt; | |
114 | ||
fb7aa03d PH |
115 | /* protected by output lock */ |
116 | unsigned int column; | |
ba2e68ac | 117 | unsigned int canon_column; |
bddc7152 JS |
118 | |
119 | struct mutex atomic_read_lock; | |
120 | struct mutex output_lock; | |
121 | struct mutex echo_lock; | |
70ece7a7 JS |
122 | }; |
123 | ||
ce74117a PH |
124 | static inline size_t read_cnt(struct n_tty_data *ldata) |
125 | { | |
a2f73be8 | 126 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
127 | } |
128 | ||
bc5a5e3f PH |
129 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
130 | { | |
131 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
132 | } | |
133 | ||
134 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
135 | { | |
136 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
137 | } | |
138 | ||
522ed776 MT |
139 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
140 | unsigned char __user *ptr) | |
141 | { | |
53c5ee2c JS |
142 | struct n_tty_data *ldata = tty->disc_data; |
143 | ||
144 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
145 | return put_user(x, ptr); |
146 | } | |
147 | ||
24a89d1c | 148 | static int receive_room(struct tty_struct *tty) |
55db4c64 | 149 | { |
53c5ee2c | 150 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 151 | int left; |
55db4c64 | 152 | |
090abf7b JA |
153 | if (I_PARMRK(tty)) { |
154 | /* Multiply read_cnt by 3, since each byte might take up to | |
155 | * three times as many spaces when PARMRK is set (depending on | |
156 | * its flags, e.g. parity error). */ | |
ce74117a | 157 | left = N_TTY_BUF_SIZE - read_cnt(ldata) * 3 - 1; |
090abf7b | 158 | } else |
ce74117a | 159 | left = N_TTY_BUF_SIZE - read_cnt(ldata) - 1; |
090abf7b | 160 | |
55db4c64 LT |
161 | /* |
162 | * If we are doing input canonicalization, and there are no | |
163 | * pending newlines, let characters through without limit, so | |
164 | * that erase characters will be handled. Other excess | |
165 | * characters will be beeped. | |
166 | */ | |
167 | if (left <= 0) | |
a73d3d69 | 168 | left = ldata->icanon && ldata->canon_head == ldata->read_tail; |
55db4c64 | 169 | |
24a89d1c | 170 | return left; |
7879a9f9 PH |
171 | } |
172 | ||
24a89d1c PH |
173 | /** |
174 | * n_tty_set_room - receive space | |
175 | * @tty: terminal | |
176 | * | |
177 | * Re-schedules the flip buffer work if space just became available. | |
178 | * | |
6d76bd26 PH |
179 | * Caller holds exclusive termios_rwsem |
180 | * or | |
181 | * n_tty_read()/consumer path: | |
182 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
183 | */ |
184 | ||
7879a9f9 PH |
185 | static void n_tty_set_room(struct tty_struct *tty) |
186 | { | |
24a89d1c PH |
187 | struct n_tty_data *ldata = tty->disc_data; |
188 | ||
55db4c64 | 189 | /* Did this open up the receive buffer? We may need to flip */ |
24a89d1c PH |
190 | if (unlikely(ldata->no_room) && receive_room(tty)) { |
191 | ldata->no_room = 0; | |
192 | ||
ecbbfd44 | 193 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 194 | "scheduling with invalid itty\n"); |
21622939 PH |
195 | /* see if ldisc has been killed - if so, this means that |
196 | * even though the ldisc has been halted and ->buf.work | |
197 | * cancelled, ->buf.work is about to be rescheduled | |
198 | */ | |
199 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
200 | "scheduling buffer work for halted ldisc\n"); | |
ecbbfd44 JS |
201 | schedule_work(&tty->port->buf.work); |
202 | } | |
55db4c64 LT |
203 | } |
204 | ||
9a4aec2d PH |
205 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
206 | { | |
207 | struct n_tty_data *ldata = tty->disc_data; | |
208 | ssize_t n = 0; | |
209 | ||
210 | if (!ldata->icanon) | |
211 | n = read_cnt(ldata); | |
212 | else | |
213 | n = ldata->canon_head - ldata->read_tail; | |
214 | return n; | |
215 | } | |
216 | ||
6367ca72 PH |
217 | static inline void n_tty_check_throttle(struct tty_struct *tty) |
218 | { | |
219 | /* | |
220 | * Check the remaining room for the input canonicalization | |
221 | * mode. We don't want to throttle the driver if we're in | |
222 | * canonical mode and don't have a newline yet! | |
223 | */ | |
224 | while (1) { | |
225 | int throttled; | |
226 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
227 | if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) | |
228 | break; | |
229 | throttled = tty_throttle_safe(tty); | |
230 | if (!throttled) | |
231 | break; | |
232 | } | |
233 | __tty_set_flow_change(tty, 0); | |
234 | } | |
235 | ||
236 | static inline void n_tty_check_unthrottle(struct tty_struct *tty) | |
237 | { | |
238 | /* If there is enough space in the read buffer now, let the | |
239 | * low-level driver know. We use chars_in_buffer() to | |
240 | * check the buffer, as it now knows about canonical mode. | |
241 | * Otherwise, if the driver is throttled and the line is | |
242 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
243 | * we won't get any more characters. | |
244 | */ | |
245 | ||
246 | while (1) { | |
247 | int unthrottled; | |
248 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
249 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
250 | break; | |
251 | if (!tty->count) | |
252 | break; | |
253 | n_tty_set_room(tty); | |
254 | unthrottled = tty_unthrottle_safe(tty); | |
255 | if (!unthrottled) | |
256 | break; | |
257 | } | |
258 | __tty_set_flow_change(tty, 0); | |
259 | } | |
260 | ||
17b82060 AC |
261 | /** |
262 | * put_tty_queue - add character to tty | |
263 | * @c: character | |
57c94121 | 264 | * @ldata: n_tty data |
17b82060 | 265 | * |
6d76bd26 PH |
266 | * Add a character to the tty read_buf queue. |
267 | * | |
268 | * n_tty_receive_buf()/producer path: | |
269 | * caller holds non-exclusive termios_rwsem | |
270 | * modifies read_head | |
271 | * | |
272 | * read_head is only considered 'published' if canonical mode is | |
273 | * not active. | |
17b82060 AC |
274 | */ |
275 | ||
57c94121 | 276 | static void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 277 | { |
6d76bd26 PH |
278 | if (read_cnt(ldata) < N_TTY_BUF_SIZE) { |
279 | *read_buf_addr(ldata, ldata->read_head) = c; | |
280 | ldata->read_head++; | |
281 | } | |
1da177e4 LT |
282 | } |
283 | ||
1da177e4 LT |
284 | /** |
285 | * reset_buffer_flags - reset buffer state | |
286 | * @tty: terminal to reset | |
287 | * | |
25518c68 PH |
288 | * Reset the read buffer counters and clear the flags. |
289 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 290 | * |
6d76bd26 PH |
291 | * Locking: caller holds exclusive termios_rwsem |
292 | * (or locking is not required) | |
1da177e4 | 293 | */ |
a88a69c9 | 294 | |
b66f4fa5 | 295 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 296 | { |
a73d3d69 | 297 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
a88a69c9 | 298 | |
bddc7152 | 299 | mutex_lock(&ldata->echo_lock); |
ba2e68ac | 300 | ldata->echo_pos = ldata->echo_cnt = ldata->echo_overrun = 0; |
bddc7152 | 301 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 | 302 | |
a73d3d69 | 303 | ldata->erasing = 0; |
3fe780b3 | 304 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
1da177e4 LT |
305 | } |
306 | ||
a30737ab PH |
307 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
308 | { | |
309 | unsigned long flags; | |
310 | ||
311 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
312 | if (tty->link->packet) { | |
313 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
314 | wake_up_interruptible(&tty->link->read_wait); | |
315 | } | |
316 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
317 | } | |
318 | ||
1da177e4 LT |
319 | /** |
320 | * n_tty_flush_buffer - clean input queue | |
321 | * @tty: terminal device | |
322 | * | |
25518c68 PH |
323 | * Flush the input buffer. Called when the tty layer wants the |
324 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
325 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 326 | * |
6d76bd26 PH |
327 | * Holds termios_rwsem to exclude producer/consumer while |
328 | * buffer indices are reset. | |
329 | * | |
330 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 331 | */ |
4edf1827 AC |
332 | |
333 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 334 | { |
6d76bd26 | 335 | down_write(&tty->termios_rwsem); |
b66f4fa5 PH |
336 | reset_buffer_flags(tty->disc_data); |
337 | n_tty_set_room(tty); | |
4edf1827 | 338 | |
a30737ab PH |
339 | if (tty->link) |
340 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 341 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
342 | } |
343 | ||
6d76bd26 PH |
344 | /** |
345 | * n_tty_chars_in_buffer - report available bytes | |
346 | * @tty: tty device | |
347 | * | |
348 | * Report the number of characters buffered to be delivered to user | |
349 | * at this instant in time. | |
350 | * | |
351 | * Locking: exclusive termios_rwsem | |
352 | */ | |
353 | ||
a19d0c6a PH |
354 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
355 | { | |
6d76bd26 PH |
356 | ssize_t n; |
357 | ||
47534084 | 358 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
6d76bd26 PH |
359 | |
360 | down_write(&tty->termios_rwsem); | |
361 | n = chars_in_buffer(tty); | |
362 | up_write(&tty->termios_rwsem); | |
363 | return n; | |
a19d0c6a PH |
364 | } |
365 | ||
1da177e4 LT |
366 | /** |
367 | * is_utf8_continuation - utf8 multibyte check | |
368 | * @c: byte to check | |
369 | * | |
370 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
371 | * character. We use this to correctly compute the on screen size | |
372 | * of the character when printing | |
373 | */ | |
4edf1827 | 374 | |
1da177e4 LT |
375 | static inline int is_utf8_continuation(unsigned char c) |
376 | { | |
377 | return (c & 0xc0) == 0x80; | |
378 | } | |
379 | ||
380 | /** | |
381 | * is_continuation - multibyte check | |
382 | * @c: byte to check | |
383 | * | |
384 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
385 | * character and the terminal is in unicode mode. | |
386 | */ | |
4edf1827 | 387 | |
1da177e4 LT |
388 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
389 | { | |
390 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
391 | } | |
392 | ||
393 | /** | |
a88a69c9 | 394 | * do_output_char - output one character |
1da177e4 LT |
395 | * @c: character (or partial unicode symbol) |
396 | * @tty: terminal device | |
a88a69c9 | 397 | * @space: space available in tty driver write buffer |
1da177e4 | 398 | * |
a88a69c9 JP |
399 | * This is a helper function that handles one output character |
400 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
401 | * doing OPOST processing and putting the results in the |
402 | * tty driver's write buffer. | |
a88a69c9 JP |
403 | * |
404 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
405 | * and NLDLY. They simply aren't relevant in the world today. | |
406 | * If you ever need them, add them here. | |
1da177e4 | 407 | * |
a88a69c9 JP |
408 | * Returns the number of bytes of buffer space used or -1 if |
409 | * no space left. | |
410 | * | |
411 | * Locking: should be called under the output_lock to protect | |
412 | * the column state and space left in the buffer | |
1da177e4 | 413 | */ |
4edf1827 | 414 | |
a88a69c9 | 415 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 416 | { |
53c5ee2c | 417 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 418 | int spaces; |
1da177e4 | 419 | |
1da177e4 LT |
420 | if (!space) |
421 | return -1; | |
300a6204 | 422 | |
a88a69c9 JP |
423 | switch (c) { |
424 | case '\n': | |
425 | if (O_ONLRET(tty)) | |
53c5ee2c | 426 | ldata->column = 0; |
a88a69c9 JP |
427 | if (O_ONLCR(tty)) { |
428 | if (space < 2) | |
429 | return -1; | |
ba2e68ac | 430 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 431 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
432 | return 2; |
433 | } | |
ba2e68ac | 434 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
435 | break; |
436 | case '\r': | |
53c5ee2c | 437 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
438 | return 0; |
439 | if (O_OCRNL(tty)) { | |
440 | c = '\n'; | |
441 | if (O_ONLRET(tty)) | |
ba2e68ac | 442 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 443 | break; |
a88a69c9 | 444 | } |
ba2e68ac | 445 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
446 | break; |
447 | case '\t': | |
53c5ee2c | 448 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
449 | if (O_TABDLY(tty) == XTABS) { |
450 | if (space < spaces) | |
451 | return -1; | |
53c5ee2c | 452 | ldata->column += spaces; |
a88a69c9 JP |
453 | tty->ops->write(tty, " ", spaces); |
454 | return spaces; | |
1da177e4 | 455 | } |
53c5ee2c | 456 | ldata->column += spaces; |
a88a69c9 JP |
457 | break; |
458 | case '\b': | |
53c5ee2c JS |
459 | if (ldata->column > 0) |
460 | ldata->column--; | |
a88a69c9 JP |
461 | break; |
462 | default: | |
a59c0d6f JP |
463 | if (!iscntrl(c)) { |
464 | if (O_OLCUC(tty)) | |
465 | c = toupper(c); | |
466 | if (!is_continuation(c, tty)) | |
53c5ee2c | 467 | ldata->column++; |
a59c0d6f | 468 | } |
a88a69c9 | 469 | break; |
1da177e4 | 470 | } |
a88a69c9 | 471 | |
f34d7a5b | 472 | tty_put_char(tty, c); |
a88a69c9 JP |
473 | return 1; |
474 | } | |
475 | ||
476 | /** | |
477 | * process_output - output post processor | |
478 | * @c: character (or partial unicode symbol) | |
479 | * @tty: terminal device | |
480 | * | |
ee5aa7b8 JP |
481 | * Output one character with OPOST processing. |
482 | * Returns -1 when the output device is full and the character | |
483 | * must be retried. | |
a88a69c9 JP |
484 | * |
485 | * Locking: output_lock to protect column state and space left | |
486 | * (also, this is called from n_tty_write under the | |
487 | * tty layer write lock) | |
488 | */ | |
489 | ||
490 | static int process_output(unsigned char c, struct tty_struct *tty) | |
491 | { | |
bddc7152 | 492 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
493 | int space, retval; |
494 | ||
bddc7152 | 495 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
496 | |
497 | space = tty_write_room(tty); | |
498 | retval = do_output_char(c, tty, space); | |
499 | ||
bddc7152 | 500 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
501 | if (retval < 0) |
502 | return -1; | |
503 | else | |
504 | return 0; | |
1da177e4 LT |
505 | } |
506 | ||
507 | /** | |
a88a69c9 | 508 | * process_output_block - block post processor |
1da177e4 | 509 | * @tty: terminal device |
ee5aa7b8 JP |
510 | * @buf: character buffer |
511 | * @nr: number of bytes to output | |
512 | * | |
513 | * Output a block of characters with OPOST processing. | |
514 | * Returns the number of characters output. | |
1da177e4 LT |
515 | * |
516 | * This path is used to speed up block console writes, among other | |
517 | * things when processing blocks of output data. It handles only | |
518 | * the simple cases normally found and helps to generate blocks of | |
519 | * symbols for the console driver and thus improve performance. | |
520 | * | |
a88a69c9 JP |
521 | * Locking: output_lock to protect column state and space left |
522 | * (also, this is called from n_tty_write under the | |
523 | * tty layer write lock) | |
1da177e4 | 524 | */ |
4edf1827 | 525 | |
a88a69c9 JP |
526 | static ssize_t process_output_block(struct tty_struct *tty, |
527 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 528 | { |
53c5ee2c | 529 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 530 | int space; |
bbd20759 | 531 | int i; |
1da177e4 LT |
532 | const unsigned char *cp; |
533 | ||
bddc7152 | 534 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 535 | |
f34d7a5b | 536 | space = tty_write_room(tty); |
300a6204 | 537 | if (!space) { |
bddc7152 | 538 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 539 | return 0; |
a88a69c9 | 540 | } |
1da177e4 LT |
541 | if (nr > space) |
542 | nr = space; | |
543 | ||
544 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
545 | unsigned char c = *cp; |
546 | ||
547 | switch (c) { | |
1da177e4 LT |
548 | case '\n': |
549 | if (O_ONLRET(tty)) | |
53c5ee2c | 550 | ldata->column = 0; |
1da177e4 LT |
551 | if (O_ONLCR(tty)) |
552 | goto break_out; | |
ba2e68ac | 553 | ldata->canon_column = ldata->column; |
1da177e4 LT |
554 | break; |
555 | case '\r': | |
53c5ee2c | 556 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
557 | goto break_out; |
558 | if (O_OCRNL(tty)) | |
559 | goto break_out; | |
ba2e68ac | 560 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
561 | break; |
562 | case '\t': | |
563 | goto break_out; | |
564 | case '\b': | |
53c5ee2c JS |
565 | if (ldata->column > 0) |
566 | ldata->column--; | |
1da177e4 LT |
567 | break; |
568 | default: | |
a59c0d6f JP |
569 | if (!iscntrl(c)) { |
570 | if (O_OLCUC(tty)) | |
571 | goto break_out; | |
572 | if (!is_continuation(c, tty)) | |
53c5ee2c | 573 | ldata->column++; |
a59c0d6f | 574 | } |
1da177e4 LT |
575 | break; |
576 | } | |
577 | } | |
578 | break_out: | |
f34d7a5b | 579 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 580 | |
bddc7152 | 581 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
582 | return i; |
583 | } | |
584 | ||
a88a69c9 JP |
585 | /** |
586 | * process_echoes - write pending echo characters | |
587 | * @tty: terminal device | |
588 | * | |
589 | * Write previously buffered echo (and other ldisc-generated) | |
590 | * characters to the tty. | |
591 | * | |
592 | * Characters generated by the ldisc (including echoes) need to | |
593 | * be buffered because the driver's write buffer can fill during | |
594 | * heavy program output. Echoing straight to the driver will | |
595 | * often fail under these conditions, causing lost characters and | |
596 | * resulting mismatches of ldisc state information. | |
597 | * | |
598 | * Since the ldisc state must represent the characters actually sent | |
599 | * to the driver at the time of the write, operations like certain | |
600 | * changes in column state are also saved in the buffer and executed | |
601 | * here. | |
602 | * | |
603 | * A circular fifo buffer is used so that the most recent characters | |
604 | * are prioritized. Also, when control characters are echoed with a | |
605 | * prefixed "^", the pair is treated atomically and thus not separated. | |
606 | * | |
607 | * Locking: output_lock to protect column state and space left, | |
608 | * echo_lock to protect the echo buffer | |
609 | */ | |
610 | ||
611 | static void process_echoes(struct tty_struct *tty) | |
612 | { | |
53c5ee2c | 613 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
614 | int space, nr; |
615 | unsigned char c; | |
616 | unsigned char *cp, *buf_end; | |
617 | ||
ba2e68ac | 618 | if (!ldata->echo_cnt) |
a88a69c9 JP |
619 | return; |
620 | ||
bddc7152 JS |
621 | mutex_lock(&ldata->output_lock); |
622 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
623 | |
624 | space = tty_write_room(tty); | |
625 | ||
ba2e68ac JS |
626 | buf_end = ldata->echo_buf + N_TTY_BUF_SIZE; |
627 | cp = ldata->echo_buf + ldata->echo_pos; | |
628 | nr = ldata->echo_cnt; | |
a88a69c9 JP |
629 | while (nr > 0) { |
630 | c = *cp; | |
631 | if (c == ECHO_OP_START) { | |
632 | unsigned char op; | |
633 | unsigned char *opp; | |
634 | int no_space_left = 0; | |
635 | ||
636 | /* | |
637 | * If the buffer byte is the start of a multi-byte | |
638 | * operation, get the next byte, which is either the | |
639 | * op code or a control character value. | |
640 | */ | |
641 | opp = cp + 1; | |
642 | if (opp == buf_end) | |
643 | opp -= N_TTY_BUF_SIZE; | |
644 | op = *opp; | |
300a6204 | 645 | |
a88a69c9 JP |
646 | switch (op) { |
647 | unsigned int num_chars, num_bs; | |
648 | ||
649 | case ECHO_OP_ERASE_TAB: | |
650 | if (++opp == buf_end) | |
651 | opp -= N_TTY_BUF_SIZE; | |
652 | num_chars = *opp; | |
653 | ||
654 | /* | |
655 | * Determine how many columns to go back | |
656 | * in order to erase the tab. | |
657 | * This depends on the number of columns | |
658 | * used by other characters within the tab | |
659 | * area. If this (modulo 8) count is from | |
660 | * the start of input rather than from a | |
661 | * previous tab, we offset by canon column. | |
662 | * Otherwise, tab spacing is normal. | |
663 | */ | |
664 | if (!(num_chars & 0x80)) | |
ba2e68ac | 665 | num_chars += ldata->canon_column; |
a88a69c9 JP |
666 | num_bs = 8 - (num_chars & 7); |
667 | ||
668 | if (num_bs > space) { | |
669 | no_space_left = 1; | |
670 | break; | |
671 | } | |
672 | space -= num_bs; | |
673 | while (num_bs--) { | |
674 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
675 | if (ldata->column > 0) |
676 | ldata->column--; | |
a88a69c9 JP |
677 | } |
678 | cp += 3; | |
679 | nr -= 3; | |
680 | break; | |
681 | ||
682 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 683 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
684 | cp += 2; |
685 | nr -= 2; | |
686 | break; | |
687 | ||
688 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
689 | if (ldata->column > 0) |
690 | ldata->column--; | |
a88a69c9 JP |
691 | cp += 2; |
692 | nr -= 2; | |
693 | break; | |
694 | ||
695 | case ECHO_OP_START: | |
696 | /* This is an escaped echo op start code */ | |
697 | if (!space) { | |
698 | no_space_left = 1; | |
699 | break; | |
700 | } | |
701 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 702 | ldata->column++; |
a88a69c9 JP |
703 | space--; |
704 | cp += 2; | |
705 | nr -= 2; | |
706 | break; | |
707 | ||
708 | default: | |
a88a69c9 | 709 | /* |
62b26358 JP |
710 | * If the op is not a special byte code, |
711 | * it is a ctrl char tagged to be echoed | |
712 | * as "^X" (where X is the letter | |
713 | * representing the control char). | |
714 | * Note that we must ensure there is | |
715 | * enough space for the whole ctrl pair. | |
716 | * | |
a88a69c9 | 717 | */ |
62b26358 JP |
718 | if (space < 2) { |
719 | no_space_left = 1; | |
720 | break; | |
721 | } | |
722 | tty_put_char(tty, '^'); | |
723 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 724 | ldata->column += 2; |
62b26358 | 725 | space -= 2; |
a88a69c9 JP |
726 | cp += 2; |
727 | nr -= 2; | |
728 | } | |
729 | ||
730 | if (no_space_left) | |
731 | break; | |
732 | } else { | |
582f5590 | 733 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
734 | int retval = do_output_char(c, tty, space); |
735 | if (retval < 0) | |
736 | break; | |
737 | space -= retval; | |
738 | } else { | |
739 | if (!space) | |
740 | break; | |
741 | tty_put_char(tty, c); | |
742 | space -= 1; | |
743 | } | |
a88a69c9 JP |
744 | cp += 1; |
745 | nr -= 1; | |
746 | } | |
747 | ||
748 | /* When end of circular buffer reached, wrap around */ | |
749 | if (cp >= buf_end) | |
750 | cp -= N_TTY_BUF_SIZE; | |
751 | } | |
752 | ||
753 | if (nr == 0) { | |
ba2e68ac JS |
754 | ldata->echo_pos = 0; |
755 | ldata->echo_cnt = 0; | |
53c5ee2c | 756 | ldata->echo_overrun = 0; |
a88a69c9 | 757 | } else { |
ba2e68ac JS |
758 | int num_processed = ldata->echo_cnt - nr; |
759 | ldata->echo_pos += num_processed; | |
760 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; | |
761 | ldata->echo_cnt = nr; | |
a88a69c9 | 762 | if (num_processed > 0) |
53c5ee2c | 763 | ldata->echo_overrun = 0; |
a88a69c9 JP |
764 | } |
765 | ||
bddc7152 JS |
766 | mutex_unlock(&ldata->echo_lock); |
767 | mutex_unlock(&ldata->output_lock); | |
a88a69c9 JP |
768 | |
769 | if (tty->ops->flush_chars) | |
770 | tty->ops->flush_chars(tty); | |
771 | } | |
772 | ||
773 | /** | |
774 | * add_echo_byte - add a byte to the echo buffer | |
775 | * @c: unicode byte to echo | |
57c94121 | 776 | * @ldata: n_tty data |
a88a69c9 JP |
777 | * |
778 | * Add a character or operation byte to the echo buffer. | |
779 | * | |
780 | * Should be called under the echo lock to protect the echo buffer. | |
781 | */ | |
782 | ||
57c94121 | 783 | static void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 JP |
784 | { |
785 | int new_byte_pos; | |
786 | ||
ba2e68ac | 787 | if (ldata->echo_cnt == N_TTY_BUF_SIZE) { |
a88a69c9 | 788 | /* Circular buffer is already at capacity */ |
ba2e68ac | 789 | new_byte_pos = ldata->echo_pos; |
a88a69c9 JP |
790 | |
791 | /* | |
792 | * Since the buffer start position needs to be advanced, | |
793 | * be sure to step by a whole operation byte group. | |
794 | */ | |
ba2e68ac JS |
795 | if (ldata->echo_buf[ldata->echo_pos] == ECHO_OP_START) { |
796 | if (ldata->echo_buf[(ldata->echo_pos + 1) & | |
a88a69c9 JP |
797 | (N_TTY_BUF_SIZE - 1)] == |
798 | ECHO_OP_ERASE_TAB) { | |
ba2e68ac JS |
799 | ldata->echo_pos += 3; |
800 | ldata->echo_cnt -= 2; | |
a88a69c9 | 801 | } else { |
ba2e68ac JS |
802 | ldata->echo_pos += 2; |
803 | ldata->echo_cnt -= 1; | |
a88a69c9 JP |
804 | } |
805 | } else { | |
ba2e68ac | 806 | ldata->echo_pos++; |
a88a69c9 | 807 | } |
ba2e68ac | 808 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; |
a88a69c9 | 809 | |
53c5ee2c | 810 | ldata->echo_overrun = 1; |
a88a69c9 | 811 | } else { |
ba2e68ac | 812 | new_byte_pos = ldata->echo_pos + ldata->echo_cnt; |
a88a69c9 | 813 | new_byte_pos &= N_TTY_BUF_SIZE - 1; |
ba2e68ac | 814 | ldata->echo_cnt++; |
a88a69c9 JP |
815 | } |
816 | ||
ba2e68ac | 817 | ldata->echo_buf[new_byte_pos] = c; |
a88a69c9 JP |
818 | } |
819 | ||
820 | /** | |
821 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 822 | * @ldata: n_tty data |
a88a69c9 JP |
823 | * |
824 | * Add an operation to the echo buffer to move back one column. | |
825 | * | |
826 | * Locking: echo_lock to protect the echo buffer | |
827 | */ | |
828 | ||
57c94121 | 829 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 830 | { |
bddc7152 | 831 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
832 | add_echo_byte(ECHO_OP_START, ldata); |
833 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
bddc7152 | 834 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
835 | } |
836 | ||
837 | /** | |
838 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 839 | * @ldata: n_tty data |
a88a69c9 JP |
840 | * |
841 | * Add an operation to the echo buffer to set the canon column | |
842 | * to the current column. | |
843 | * | |
844 | * Locking: echo_lock to protect the echo buffer | |
845 | */ | |
846 | ||
57c94121 | 847 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 848 | { |
bddc7152 | 849 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
850 | add_echo_byte(ECHO_OP_START, ldata); |
851 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
bddc7152 | 852 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
853 | } |
854 | ||
855 | /** | |
856 | * echo_erase_tab - add operation to erase a tab | |
857 | * @num_chars: number of character columns already used | |
858 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 859 | * @ldata: n_tty data |
a88a69c9 JP |
860 | * |
861 | * Add an operation to the echo buffer to erase a tab. | |
862 | * | |
863 | * Called by the eraser function, which knows how many character | |
864 | * columns have been used since either a previous tab or the start | |
865 | * of input. This information will be used later, along with | |
866 | * canon column (if applicable), to go back the correct number | |
867 | * of columns. | |
868 | * | |
869 | * Locking: echo_lock to protect the echo buffer | |
870 | */ | |
871 | ||
872 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 873 | struct n_tty_data *ldata) |
a88a69c9 | 874 | { |
bddc7152 | 875 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 876 | |
57c94121 JS |
877 | add_echo_byte(ECHO_OP_START, ldata); |
878 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
879 | |
880 | /* We only need to know this modulo 8 (tab spacing) */ | |
881 | num_chars &= 7; | |
882 | ||
883 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
884 | if (after_tab) | |
885 | num_chars |= 0x80; | |
300a6204 | 886 | |
57c94121 | 887 | add_echo_byte(num_chars, ldata); |
a88a69c9 | 888 | |
bddc7152 | 889 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
890 | } |
891 | ||
892 | /** | |
893 | * echo_char_raw - echo a character raw | |
894 | * @c: unicode byte to echo | |
895 | * @tty: terminal device | |
896 | * | |
897 | * Echo user input back onto the screen. This must be called only when | |
898 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
899 | * | |
900 | * This variant does not treat control characters specially. | |
901 | * | |
902 | * Locking: echo_lock to protect the echo buffer | |
903 | */ | |
904 | ||
57c94121 | 905 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 906 | { |
bddc7152 | 907 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 908 | if (c == ECHO_OP_START) { |
57c94121 JS |
909 | add_echo_byte(ECHO_OP_START, ldata); |
910 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 911 | } else { |
57c94121 | 912 | add_echo_byte(c, ldata); |
a88a69c9 | 913 | } |
bddc7152 | 914 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 | 915 | } |
1da177e4 | 916 | |
1da177e4 | 917 | /** |
a88a69c9 | 918 | * echo_char - echo a character |
1da177e4 LT |
919 | * @c: unicode byte to echo |
920 | * @tty: terminal device | |
921 | * | |
4edf1827 | 922 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 923 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 924 | * |
62b26358 JP |
925 | * This variant tags control characters to be echoed as "^X" |
926 | * (where X is the letter representing the control char). | |
a88a69c9 JP |
927 | * |
928 | * Locking: echo_lock to protect the echo buffer | |
1da177e4 LT |
929 | */ |
930 | ||
931 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
932 | { | |
bddc7152 JS |
933 | struct n_tty_data *ldata = tty->disc_data; |
934 | ||
935 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
936 | |
937 | if (c == ECHO_OP_START) { | |
57c94121 JS |
938 | add_echo_byte(ECHO_OP_START, ldata); |
939 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 940 | } else { |
62b26358 | 941 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
942 | add_echo_byte(ECHO_OP_START, ldata); |
943 | add_echo_byte(c, ldata); | |
a88a69c9 JP |
944 | } |
945 | ||
bddc7152 | 946 | mutex_unlock(&ldata->echo_lock); |
1da177e4 LT |
947 | } |
948 | ||
17b82060 | 949 | /** |
a88a69c9 | 950 | * finish_erasing - complete erase |
57c94121 | 951 | * @ldata: n_tty data |
17b82060 | 952 | */ |
a88a69c9 | 953 | |
57c94121 | 954 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 955 | { |
53c5ee2c | 956 | if (ldata->erasing) { |
57c94121 | 957 | echo_char_raw('/', ldata); |
53c5ee2c | 958 | ldata->erasing = 0; |
1da177e4 LT |
959 | } |
960 | } | |
961 | ||
962 | /** | |
963 | * eraser - handle erase function | |
964 | * @c: character input | |
965 | * @tty: terminal device | |
966 | * | |
3a4fa0a2 | 967 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
968 | * present in the stream from the driver layer. Handles the complexities |
969 | * of UTF-8 multibyte symbols. | |
17b82060 | 970 | * |
6d76bd26 PH |
971 | * n_tty_receive_buf()/producer path: |
972 | * caller holds non-exclusive termios_rwsem | |
973 | * modifies read_head | |
974 | * | |
975 | * Modifying the read_head is not considered a publish in this context | |
976 | * because canonical mode is active -- only canon_head publishes | |
1da177e4 | 977 | */ |
4edf1827 | 978 | |
1da177e4 LT |
979 | static void eraser(unsigned char c, struct tty_struct *tty) |
980 | { | |
53c5ee2c | 981 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 982 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
983 | size_t head; |
984 | size_t cnt; | |
985 | int seen_alnums; | |
1da177e4 | 986 | |
ba2e68ac | 987 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 988 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
989 | return; |
990 | } | |
991 | if (c == ERASE_CHAR(tty)) | |
992 | kill_type = ERASE; | |
993 | else if (c == WERASE_CHAR(tty)) | |
994 | kill_type = WERASE; | |
995 | else { | |
996 | if (!L_ECHO(tty)) { | |
ba2e68ac | 997 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
998 | return; |
999 | } | |
1000 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 1001 | ldata->read_head = ldata->canon_head; |
57c94121 | 1002 | finish_erasing(ldata); |
1da177e4 LT |
1003 | echo_char(KILL_CHAR(tty), tty); |
1004 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
1005 | if (L_ECHOK(tty)) | |
57c94121 | 1006 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1007 | return; |
1008 | } | |
1009 | kill_type = KILL; | |
1010 | } | |
1011 | ||
1012 | seen_alnums = 0; | |
ba2e68ac JS |
1013 | while (ldata->read_head != ldata->canon_head) { |
1014 | head = ldata->read_head; | |
1da177e4 LT |
1015 | |
1016 | /* erase a single possibly multibyte character */ | |
1017 | do { | |
bc5a5e3f PH |
1018 | head--; |
1019 | c = read_buf(ldata, head); | |
ba2e68ac | 1020 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1021 | |
1022 | /* do not partially erase */ | |
1023 | if (is_continuation(c, tty)) | |
1024 | break; | |
1025 | ||
1026 | if (kill_type == WERASE) { | |
1027 | /* Equivalent to BSD's ALTWERASE. */ | |
1028 | if (isalnum(c) || c == '_') | |
1029 | seen_alnums++; | |
1030 | else if (seen_alnums) | |
1031 | break; | |
1032 | } | |
bc5a5e3f | 1033 | cnt = ldata->read_head - head; |
ba2e68ac | 1034 | ldata->read_head = head; |
1da177e4 LT |
1035 | if (L_ECHO(tty)) { |
1036 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1037 | if (!ldata->erasing) { |
57c94121 | 1038 | echo_char_raw('\\', ldata); |
53c5ee2c | 1039 | ldata->erasing = 1; |
1da177e4 LT |
1040 | } |
1041 | /* if cnt > 1, output a multi-byte character */ | |
1042 | echo_char(c, tty); | |
1043 | while (--cnt > 0) { | |
bc5a5e3f PH |
1044 | head++; |
1045 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1046 | echo_move_back_col(ldata); |
1da177e4 LT |
1047 | } |
1048 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1049 | echo_char(ERASE_CHAR(tty), tty); | |
1050 | } else if (c == '\t') { | |
a88a69c9 JP |
1051 | unsigned int num_chars = 0; |
1052 | int after_tab = 0; | |
bc5a5e3f | 1053 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1054 | |
1055 | /* | |
1056 | * Count the columns used for characters | |
1057 | * since the start of input or after a | |
1058 | * previous tab. | |
1059 | * This info is used to go back the correct | |
1060 | * number of columns. | |
1061 | */ | |
ba2e68ac | 1062 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1063 | tail--; |
1064 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1065 | if (c == '\t') { |
1066 | after_tab = 1; | |
1067 | break; | |
300a6204 | 1068 | } else if (iscntrl(c)) { |
1da177e4 | 1069 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1070 | num_chars += 2; |
1071 | } else if (!is_continuation(c, tty)) { | |
1072 | num_chars++; | |
1073 | } | |
1da177e4 | 1074 | } |
57c94121 | 1075 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1076 | } else { |
1077 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1078 | echo_char_raw('\b', ldata); |
1079 | echo_char_raw(' ', ldata); | |
1080 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1081 | } |
1082 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1083 | echo_char_raw('\b', ldata); |
1084 | echo_char_raw(' ', ldata); | |
1085 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1086 | } |
1087 | } | |
1088 | } | |
1089 | if (kill_type == ERASE) | |
1090 | break; | |
1091 | } | |
ba2e68ac | 1092 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1093 | finish_erasing(ldata); |
1da177e4 LT |
1094 | } |
1095 | ||
1096 | /** | |
1097 | * isig - handle the ISIG optio | |
1098 | * @sig: signal | |
1099 | * @tty: terminal | |
1da177e4 | 1100 | * |
8c985d18 PH |
1101 | * Called when a signal is being sent due to terminal input. |
1102 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1103 | * |
8c985d18 | 1104 | * Locking: ctrl_lock |
1da177e4 | 1105 | */ |
4edf1827 | 1106 | |
8c985d18 | 1107 | static inline void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1108 | { |
8c985d18 PH |
1109 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1110 | if (tty_pgrp) { | |
1111 | kill_pgrp(tty_pgrp, sig, 1); | |
1112 | put_pid(tty_pgrp); | |
1da177e4 LT |
1113 | } |
1114 | } | |
1115 | ||
1116 | /** | |
1117 | * n_tty_receive_break - handle break | |
1118 | * @tty: terminal | |
1119 | * | |
1120 | * An RS232 break event has been hit in the incoming bitstream. This | |
1121 | * can cause a variety of events depending upon the termios settings. | |
1122 | * | |
6d76bd26 PH |
1123 | * n_tty_receive_buf()/producer path: |
1124 | * caller holds non-exclusive termios_rwsem | |
1125 | * publishes read_head via put_tty_queue() | |
1126 | * | |
1127 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1128 | */ |
4edf1827 | 1129 | |
1da177e4 LT |
1130 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1131 | { | |
57c94121 JS |
1132 | struct n_tty_data *ldata = tty->disc_data; |
1133 | ||
1da177e4 LT |
1134 | if (I_IGNBRK(tty)) |
1135 | return; | |
1136 | if (I_BRKINT(tty)) { | |
8c985d18 PH |
1137 | isig(SIGINT, tty); |
1138 | if (!L_NOFLSH(tty)) { | |
6d76bd26 PH |
1139 | /* flushing needs exclusive termios_rwsem */ |
1140 | up_read(&tty->termios_rwsem); | |
8c985d18 PH |
1141 | n_tty_flush_buffer(tty); |
1142 | tty_driver_flush_buffer(tty); | |
6d76bd26 | 1143 | down_read(&tty->termios_rwsem); |
8c985d18 | 1144 | } |
1da177e4 LT |
1145 | return; |
1146 | } | |
1147 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1148 | put_tty_queue('\377', ldata); |
1149 | put_tty_queue('\0', ldata); | |
1da177e4 | 1150 | } |
57c94121 | 1151 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1152 | wake_up_interruptible(&tty->read_wait); |
1153 | } | |
1154 | ||
1155 | /** | |
1156 | * n_tty_receive_overrun - handle overrun reporting | |
1157 | * @tty: terminal | |
1158 | * | |
1159 | * Data arrived faster than we could process it. While the tty | |
1160 | * driver has flagged this the bits that were missed are gone | |
1161 | * forever. | |
1162 | * | |
1163 | * Called from the receive_buf path so single threaded. Does not | |
1164 | * need locking as num_overrun and overrun_time are function | |
1165 | * private. | |
1166 | */ | |
4edf1827 | 1167 | |
1da177e4 LT |
1168 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1169 | { | |
53c5ee2c | 1170 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1171 | char buf[64]; |
1172 | ||
53c5ee2c JS |
1173 | ldata->num_overrun++; |
1174 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1175 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1176 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1177 | tty_name(tty, buf), | |
53c5ee2c JS |
1178 | ldata->num_overrun); |
1179 | ldata->overrun_time = jiffies; | |
1180 | ldata->num_overrun = 0; | |
1da177e4 LT |
1181 | } |
1182 | } | |
1183 | ||
1184 | /** | |
1185 | * n_tty_receive_parity_error - error notifier | |
1186 | * @tty: terminal device | |
1187 | * @c: character | |
1188 | * | |
1189 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1190 | * the error case if necessary. |
1191 | * | |
1192 | * n_tty_receive_buf()/producer path: | |
1193 | * caller holds non-exclusive termios_rwsem | |
1194 | * publishes read_head via put_tty_queue() | |
1da177e4 LT |
1195 | */ |
1196 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1197 | unsigned char c) | |
1198 | { | |
57c94121 JS |
1199 | struct n_tty_data *ldata = tty->disc_data; |
1200 | ||
4edf1827 | 1201 | if (I_IGNPAR(tty)) |
1da177e4 | 1202 | return; |
1da177e4 | 1203 | if (I_PARMRK(tty)) { |
57c94121 JS |
1204 | put_tty_queue('\377', ldata); |
1205 | put_tty_queue('\0', ldata); | |
1206 | put_tty_queue(c, ldata); | |
1da177e4 | 1207 | } else if (I_INPCK(tty)) |
57c94121 | 1208 | put_tty_queue('\0', ldata); |
1da177e4 | 1209 | else |
57c94121 | 1210 | put_tty_queue(c, ldata); |
1da177e4 LT |
1211 | wake_up_interruptible(&tty->read_wait); |
1212 | } | |
1213 | ||
1214 | /** | |
1215 | * n_tty_receive_char - perform processing | |
1216 | * @tty: terminal device | |
1217 | * @c: character | |
1218 | * | |
1219 | * Process an individual character of input received from the driver. | |
4edf1827 | 1220 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1221 | * driver above. |
6d76bd26 PH |
1222 | * |
1223 | * n_tty_receive_buf()/producer path: | |
1224 | * caller holds non-exclusive termios_rwsem | |
1225 | * publishes canon_head if canonical mode is active | |
1226 | * otherwise, publishes read_head via put_tty_queue() | |
1da177e4 LT |
1227 | */ |
1228 | ||
1229 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1230 | { | |
53c5ee2c | 1231 | struct n_tty_data *ldata = tty->disc_data; |
acc71bba | 1232 | int parmrk; |
1da177e4 | 1233 | |
53c5ee2c | 1234 | if (ldata->raw) { |
57c94121 | 1235 | put_tty_queue(c, ldata); |
1da177e4 LT |
1236 | return; |
1237 | } | |
4edf1827 | 1238 | |
1da177e4 LT |
1239 | if (I_ISTRIP(tty)) |
1240 | c &= 0x7f; | |
1241 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1242 | c = tolower(c); |
1da177e4 | 1243 | |
26df6d13 | 1244 | if (L_EXTPROC(tty)) { |
57c94121 | 1245 | put_tty_queue(c, ldata); |
26df6d13 | 1246 | return; |
1247 | } | |
1248 | ||
54d2a37e | 1249 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1250 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1251 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1252 | start_tty(tty); |
a88a69c9 JP |
1253 | process_echoes(tty); |
1254 | } | |
54d2a37e | 1255 | |
1da177e4 LT |
1256 | if (tty->closing) { |
1257 | if (I_IXON(tty)) { | |
a88a69c9 | 1258 | if (c == START_CHAR(tty)) { |
1da177e4 | 1259 | start_tty(tty); |
a88a69c9 | 1260 | process_echoes(tty); |
300a6204 | 1261 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1262 | stop_tty(tty); |
1263 | } | |
1264 | return; | |
1265 | } | |
1266 | ||
1267 | /* | |
1268 | * If the previous character was LNEXT, or we know that this | |
1269 | * character is not one of the characters that we'll have to | |
1270 | * handle specially, do shortcut processing to speed things | |
1271 | * up. | |
1272 | */ | |
3fe780b3 | 1273 | if (!test_bit(c, ldata->process_char_map) || ldata->lnext) { |
53c5ee2c | 1274 | ldata->lnext = 0; |
acc71bba | 1275 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ce74117a | 1276 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1277 | /* beep if no space */ |
7e94b1d9 JP |
1278 | if (L_ECHO(tty)) |
1279 | process_output('\a', tty); | |
acc71bba JP |
1280 | return; |
1281 | } | |
1282 | if (L_ECHO(tty)) { | |
57c94121 | 1283 | finish_erasing(ldata); |
1da177e4 | 1284 | /* Record the column of first canon char. */ |
ba2e68ac | 1285 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1286 | echo_set_canon_col(ldata); |
1da177e4 | 1287 | echo_char(c, tty); |
a88a69c9 | 1288 | process_echoes(tty); |
1da177e4 | 1289 | } |
acc71bba | 1290 | if (parmrk) |
57c94121 JS |
1291 | put_tty_queue(c, ldata); |
1292 | put_tty_queue(c, ldata); | |
1da177e4 LT |
1293 | return; |
1294 | } | |
4edf1827 | 1295 | |
1da177e4 LT |
1296 | if (I_IXON(tty)) { |
1297 | if (c == START_CHAR(tty)) { | |
1298 | start_tty(tty); | |
a88a69c9 | 1299 | process_echoes(tty); |
1da177e4 LT |
1300 | return; |
1301 | } | |
1302 | if (c == STOP_CHAR(tty)) { | |
1303 | stop_tty(tty); | |
1304 | return; | |
1305 | } | |
1306 | } | |
575537b3 | 1307 | |
1da177e4 LT |
1308 | if (L_ISIG(tty)) { |
1309 | int signal; | |
1310 | signal = SIGINT; | |
1311 | if (c == INTR_CHAR(tty)) | |
1312 | goto send_signal; | |
1313 | signal = SIGQUIT; | |
1314 | if (c == QUIT_CHAR(tty)) | |
1315 | goto send_signal; | |
1316 | signal = SIGTSTP; | |
1317 | if (c == SUSP_CHAR(tty)) { | |
1318 | send_signal: | |
ec5b1157 | 1319 | if (!L_NOFLSH(tty)) { |
6d76bd26 PH |
1320 | /* flushing needs exclusive termios_rwsem */ |
1321 | up_read(&tty->termios_rwsem); | |
ec5b1157 | 1322 | n_tty_flush_buffer(tty); |
f34d7a5b | 1323 | tty_driver_flush_buffer(tty); |
6d76bd26 | 1324 | down_read(&tty->termios_rwsem); |
ec5b1157 | 1325 | } |
a88a69c9 JP |
1326 | if (I_IXON(tty)) |
1327 | start_tty(tty); | |
1328 | if (L_ECHO(tty)) { | |
ec5b1157 | 1329 | echo_char(c, tty); |
a88a69c9 JP |
1330 | process_echoes(tty); |
1331 | } | |
8c985d18 | 1332 | isig(signal, tty); |
1da177e4 LT |
1333 | return; |
1334 | } | |
1335 | } | |
575537b3 JP |
1336 | |
1337 | if (c == '\r') { | |
1338 | if (I_IGNCR(tty)) | |
1339 | return; | |
1340 | if (I_ICRNL(tty)) | |
1341 | c = '\n'; | |
1342 | } else if (c == '\n' && I_INLCR(tty)) | |
1343 | c = '\r'; | |
1344 | ||
53c5ee2c | 1345 | if (ldata->icanon) { |
1da177e4 LT |
1346 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1347 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1348 | eraser(c, tty); | |
a88a69c9 | 1349 | process_echoes(tty); |
1da177e4 LT |
1350 | return; |
1351 | } | |
1352 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1353 | ldata->lnext = 1; |
1da177e4 | 1354 | if (L_ECHO(tty)) { |
57c94121 | 1355 | finish_erasing(ldata); |
1da177e4 | 1356 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1357 | echo_char_raw('^', ldata); |
1358 | echo_char_raw('\b', ldata); | |
a88a69c9 | 1359 | process_echoes(tty); |
1da177e4 LT |
1360 | } |
1361 | } | |
1362 | return; | |
1363 | } | |
1364 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1365 | L_IEXTEN(tty)) { | |
bc5a5e3f | 1366 | size_t tail = ldata->canon_head; |
1da177e4 | 1367 | |
57c94121 | 1368 | finish_erasing(ldata); |
1da177e4 | 1369 | echo_char(c, tty); |
57c94121 | 1370 | echo_char_raw('\n', ldata); |
ba2e68ac | 1371 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1372 | echo_char(read_buf(ldata, tail), tty); |
1373 | tail++; | |
1da177e4 | 1374 | } |
a88a69c9 | 1375 | process_echoes(tty); |
1da177e4 LT |
1376 | return; |
1377 | } | |
1378 | if (c == '\n') { | |
ce74117a | 1379 | if (read_cnt(ldata) >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1380 | if (L_ECHO(tty)) |
1381 | process_output('\a', tty); | |
acc71bba JP |
1382 | return; |
1383 | } | |
1384 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
57c94121 | 1385 | echo_char_raw('\n', ldata); |
a88a69c9 | 1386 | process_echoes(tty); |
1da177e4 LT |
1387 | } |
1388 | goto handle_newline; | |
1389 | } | |
1390 | if (c == EOF_CHAR(tty)) { | |
ce74117a | 1391 | if (read_cnt(ldata) >= N_TTY_BUF_SIZE) |
acc71bba | 1392 | return; |
ba2e68ac | 1393 | if (ldata->canon_head != ldata->read_head) |
4edf1827 | 1394 | set_bit(TTY_PUSH, &tty->flags); |
1da177e4 LT |
1395 | c = __DISABLED_CHAR; |
1396 | goto handle_newline; | |
1397 | } | |
1398 | if ((c == EOL_CHAR(tty)) || | |
1399 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1400 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1401 | ? 1 : 0; | |
ce74117a | 1402 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk)) { |
7e94b1d9 JP |
1403 | if (L_ECHO(tty)) |
1404 | process_output('\a', tty); | |
acc71bba JP |
1405 | return; |
1406 | } | |
1da177e4 LT |
1407 | /* |
1408 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1409 | */ | |
1410 | if (L_ECHO(tty)) { | |
1da177e4 | 1411 | /* Record the column of first canon char. */ |
ba2e68ac | 1412 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1413 | echo_set_canon_col(ldata); |
1da177e4 | 1414 | echo_char(c, tty); |
a88a69c9 | 1415 | process_echoes(tty); |
1da177e4 LT |
1416 | } |
1417 | /* | |
1418 | * XXX does PARMRK doubling happen for | |
1419 | * EOL_CHAR and EOL2_CHAR? | |
1420 | */ | |
acc71bba | 1421 | if (parmrk) |
57c94121 | 1422 | put_tty_queue(c, ldata); |
1da177e4 | 1423 | |
4edf1827 | 1424 | handle_newline: |
bc5a5e3f | 1425 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1426 | put_tty_queue(c, ldata); |
ba2e68ac | 1427 | ldata->canon_head = ldata->read_head; |
1da177e4 LT |
1428 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1429 | if (waitqueue_active(&tty->read_wait)) | |
1430 | wake_up_interruptible(&tty->read_wait); | |
1431 | return; | |
1432 | } | |
1433 | } | |
4edf1827 | 1434 | |
acc71bba | 1435 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ce74117a | 1436 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1437 | /* beep if no space */ |
7e94b1d9 JP |
1438 | if (L_ECHO(tty)) |
1439 | process_output('\a', tty); | |
acc71bba JP |
1440 | return; |
1441 | } | |
1442 | if (L_ECHO(tty)) { | |
57c94121 | 1443 | finish_erasing(ldata); |
1da177e4 | 1444 | if (c == '\n') |
57c94121 | 1445 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1446 | else { |
1447 | /* Record the column of first canon char. */ | |
ba2e68ac | 1448 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1449 | echo_set_canon_col(ldata); |
1da177e4 LT |
1450 | echo_char(c, tty); |
1451 | } | |
a88a69c9 | 1452 | process_echoes(tty); |
1da177e4 LT |
1453 | } |
1454 | ||
acc71bba | 1455 | if (parmrk) |
57c94121 | 1456 | put_tty_queue(c, ldata); |
1da177e4 | 1457 | |
57c94121 | 1458 | put_tty_queue(c, ldata); |
4edf1827 | 1459 | } |
1da177e4 | 1460 | |
1da177e4 LT |
1461 | |
1462 | /** | |
1463 | * n_tty_write_wakeup - asynchronous I/O notifier | |
1464 | * @tty: tty device | |
1465 | * | |
1466 | * Required for the ptys, serial driver etc. since processes | |
1467 | * that attach themselves to the master and rely on ASYNC | |
1468 | * IO must be woken up | |
1469 | */ | |
1470 | ||
1471 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
1472 | { | |
ff8cb0fd | 1473 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) |
1da177e4 | 1474 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); |
1da177e4 LT |
1475 | } |
1476 | ||
1477 | /** | |
1478 | * n_tty_receive_buf - data receive | |
1479 | * @tty: terminal device | |
1480 | * @cp: buffer | |
1481 | * @fp: flag buffer | |
1482 | * @count: characters | |
1483 | * | |
1484 | * Called by the terminal driver when a block of characters has | |
1485 | * been received. This function must be called from soft contexts | |
1486 | * not from interrupt context. The driver is responsible for making | |
1487 | * calls one at a time and in order (or using flush_to_ldisc) | |
6d76bd26 PH |
1488 | * |
1489 | * n_tty_receive_buf()/producer path: | |
1490 | * claims non-exclusive termios_rwsem | |
1491 | * publishes read_head and canon_head | |
1da177e4 | 1492 | */ |
4edf1827 | 1493 | |
24a89d1c PH |
1494 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1495 | char *fp, int count) | |
1da177e4 | 1496 | { |
53c5ee2c | 1497 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1498 | const unsigned char *p; |
1499 | char *f, flags = TTY_NORMAL; | |
1da177e4 | 1500 | char buf[64]; |
1da177e4 | 1501 | |
53c5ee2c | 1502 | if (ldata->real_raw) { |
d1913e39 PH |
1503 | size_t n, head; |
1504 | ||
1505 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1506 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1507 | n = min_t(size_t, count, n); | |
1508 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1509 | ldata->read_head += n; | |
1510 | cp += n; | |
1511 | count -= n; | |
1512 | ||
1513 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1514 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1515 | n = min_t(size_t, count, n); | |
1516 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1517 | ldata->read_head += n; | |
1da177e4 | 1518 | } else { |
d1913e39 PH |
1519 | int i; |
1520 | ||
4edf1827 | 1521 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1522 | if (f) |
1523 | flags = *f++; | |
1524 | switch (flags) { | |
1525 | case TTY_NORMAL: | |
1526 | n_tty_receive_char(tty, *p); | |
1527 | break; | |
1528 | case TTY_BREAK: | |
1529 | n_tty_receive_break(tty); | |
1530 | break; | |
1531 | case TTY_PARITY: | |
1532 | case TTY_FRAME: | |
1533 | n_tty_receive_parity_error(tty, *p); | |
1534 | break; | |
1535 | case TTY_OVERRUN: | |
1536 | n_tty_receive_overrun(tty); | |
1537 | break; | |
1538 | default: | |
4edf1827 | 1539 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1540 | tty_name(tty, buf), flags); |
1541 | break; | |
1542 | } | |
1543 | } | |
f34d7a5b AC |
1544 | if (tty->ops->flush_chars) |
1545 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1546 | } |
1547 | ||
ce74117a | 1548 | if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) || |
26df6d13 | 1549 | L_EXTPROC(tty)) { |
1da177e4 LT |
1550 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1551 | if (waitqueue_active(&tty->read_wait)) | |
1552 | wake_up_interruptible(&tty->read_wait); | |
1553 | } | |
1554 | ||
6367ca72 | 1555 | n_tty_check_throttle(tty); |
1da177e4 LT |
1556 | } |
1557 | ||
24a89d1c PH |
1558 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1559 | char *fp, int count) | |
1560 | { | |
9356b535 | 1561 | down_read(&tty->termios_rwsem); |
24a89d1c | 1562 | __receive_buf(tty, cp, fp, count); |
9356b535 | 1563 | up_read(&tty->termios_rwsem); |
24a89d1c PH |
1564 | } |
1565 | ||
1566 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1567 | char *fp, int count) | |
1568 | { | |
1569 | struct n_tty_data *ldata = tty->disc_data; | |
1570 | int room; | |
1571 | ||
9356b535 PH |
1572 | down_read(&tty->termios_rwsem); |
1573 | ||
24a89d1c PH |
1574 | tty->receive_room = room = receive_room(tty); |
1575 | if (!room) | |
1576 | ldata->no_room = 1; | |
1577 | count = min(count, room); | |
1578 | if (count) | |
1579 | __receive_buf(tty, cp, fp, count); | |
1580 | ||
9356b535 PH |
1581 | up_read(&tty->termios_rwsem); |
1582 | ||
24a89d1c PH |
1583 | return count; |
1584 | } | |
1585 | ||
1da177e4 LT |
1586 | int is_ignored(int sig) |
1587 | { | |
1588 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1589 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1590 | } |
1591 | ||
1592 | /** | |
1593 | * n_tty_set_termios - termios data changed | |
1594 | * @tty: terminal | |
1595 | * @old: previous data | |
1596 | * | |
1597 | * Called by the tty layer when the user changes termios flags so | |
1598 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1599 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1600 | * guaranteed that this function will not be re-entered or in progress |
1601 | * when the ldisc is closed. | |
17b82060 | 1602 | * |
6a1c0680 | 1603 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1604 | */ |
4edf1827 AC |
1605 | |
1606 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1607 | { |
53c5ee2c | 1608 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1609 | int canon_change = 1; |
47afa7a5 AC |
1610 | |
1611 | if (old) | |
adc8d746 | 1612 | canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON; |
47afa7a5 | 1613 | if (canon_change) { |
3fe780b3 | 1614 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
ba2e68ac | 1615 | ldata->canon_head = ldata->read_tail; |
53c5ee2c | 1616 | ldata->erasing = 0; |
6f9b028a | 1617 | ldata->lnext = 0; |
47afa7a5 AC |
1618 | } |
1619 | ||
ce74117a | 1620 | if (canon_change && !L_ICANON(tty) && read_cnt(ldata)) |
47afa7a5 | 1621 | wake_up_interruptible(&tty->read_wait); |
4edf1827 | 1622 | |
53c5ee2c | 1623 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1624 | |
1da177e4 LT |
1625 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1626 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1627 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1628 | I_PARMRK(tty)) { | |
3fe780b3 | 1629 | bitmap_zero(ldata->process_char_map, 256); |
1da177e4 LT |
1630 | |
1631 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
3fe780b3 | 1632 | set_bit('\r', ldata->process_char_map); |
1da177e4 | 1633 | if (I_INLCR(tty)) |
3fe780b3 | 1634 | set_bit('\n', ldata->process_char_map); |
1da177e4 LT |
1635 | |
1636 | if (L_ICANON(tty)) { | |
3fe780b3 JS |
1637 | set_bit(ERASE_CHAR(tty), ldata->process_char_map); |
1638 | set_bit(KILL_CHAR(tty), ldata->process_char_map); | |
1639 | set_bit(EOF_CHAR(tty), ldata->process_char_map); | |
1640 | set_bit('\n', ldata->process_char_map); | |
1641 | set_bit(EOL_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1642 | if (L_IEXTEN(tty)) { |
1643 | set_bit(WERASE_CHAR(tty), | |
3fe780b3 | 1644 | ldata->process_char_map); |
1da177e4 | 1645 | set_bit(LNEXT_CHAR(tty), |
3fe780b3 | 1646 | ldata->process_char_map); |
1da177e4 | 1647 | set_bit(EOL2_CHAR(tty), |
3fe780b3 | 1648 | ldata->process_char_map); |
1da177e4 LT |
1649 | if (L_ECHO(tty)) |
1650 | set_bit(REPRINT_CHAR(tty), | |
3fe780b3 | 1651 | ldata->process_char_map); |
1da177e4 LT |
1652 | } |
1653 | } | |
1654 | if (I_IXON(tty)) { | |
3fe780b3 JS |
1655 | set_bit(START_CHAR(tty), ldata->process_char_map); |
1656 | set_bit(STOP_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1657 | } |
1658 | if (L_ISIG(tty)) { | |
3fe780b3 JS |
1659 | set_bit(INTR_CHAR(tty), ldata->process_char_map); |
1660 | set_bit(QUIT_CHAR(tty), ldata->process_char_map); | |
1661 | set_bit(SUSP_CHAR(tty), ldata->process_char_map); | |
1da177e4 | 1662 | } |
3fe780b3 | 1663 | clear_bit(__DISABLED_CHAR, ldata->process_char_map); |
53c5ee2c JS |
1664 | ldata->raw = 0; |
1665 | ldata->real_raw = 0; | |
1da177e4 | 1666 | } else { |
53c5ee2c | 1667 | ldata->raw = 1; |
1da177e4 LT |
1668 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1669 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1670 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1671 | ldata->real_raw = 1; |
1da177e4 | 1672 | else |
53c5ee2c | 1673 | ldata->real_raw = 0; |
1da177e4 | 1674 | } |
55db4c64 | 1675 | n_tty_set_room(tty); |
dab73b4e WY |
1676 | /* |
1677 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1678 | * been stopped by STOP_CHAR(tty) before it. | |
1679 | */ | |
1680 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { | |
1681 | start_tty(tty); | |
1682 | } | |
1683 | ||
f34d7a5b AC |
1684 | /* The termios change make the tty ready for I/O */ |
1685 | wake_up_interruptible(&tty->write_wait); | |
1686 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1687 | } |
1688 | ||
1689 | /** | |
1690 | * n_tty_close - close the ldisc for this tty | |
1691 | * @tty: device | |
1692 | * | |
4edf1827 AC |
1693 | * Called from the terminal layer when this line discipline is |
1694 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1695 | * discipline change. The function will not be called while other |
1696 | * ldisc methods are in progress. | |
1697 | */ | |
4edf1827 | 1698 | |
1da177e4 LT |
1699 | static void n_tty_close(struct tty_struct *tty) |
1700 | { | |
70ece7a7 JS |
1701 | struct n_tty_data *ldata = tty->disc_data; |
1702 | ||
79901317 PH |
1703 | if (tty->link) |
1704 | n_tty_packet_mode_flush(tty); | |
1705 | ||
ba2e68ac JS |
1706 | kfree(ldata->read_buf); |
1707 | kfree(ldata->echo_buf); | |
70ece7a7 | 1708 | kfree(ldata); |
70ece7a7 | 1709 | tty->disc_data = NULL; |
1da177e4 LT |
1710 | } |
1711 | ||
1712 | /** | |
1713 | * n_tty_open - open an ldisc | |
1714 | * @tty: terminal to open | |
1715 | * | |
4edf1827 | 1716 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1717 | * terminal device. Can sleep. Called serialized so that no |
1718 | * other events will occur in parallel. No further open will occur | |
1719 | * until a close. | |
1720 | */ | |
1721 | ||
1722 | static int n_tty_open(struct tty_struct *tty) | |
1723 | { | |
70ece7a7 JS |
1724 | struct n_tty_data *ldata; |
1725 | ||
1726 | ldata = kzalloc(sizeof(*ldata), GFP_KERNEL); | |
1727 | if (!ldata) | |
1728 | goto err; | |
1729 | ||
53c5ee2c | 1730 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1731 | mutex_init(&ldata->atomic_read_lock); |
1732 | mutex_init(&ldata->output_lock); | |
1733 | mutex_init(&ldata->echo_lock); | |
53c5ee2c | 1734 | |
a88a69c9 | 1735 | /* These are ugly. Currently a malloc failure here can panic */ |
ba2e68ac JS |
1736 | ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1737 | ldata->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); | |
1738 | if (!ldata->read_buf || !ldata->echo_buf) | |
b91939f5 | 1739 | goto err_free_bufs; |
0b4068a1 | 1740 | |
70ece7a7 | 1741 | tty->disc_data = ldata; |
b66f4fa5 | 1742 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1743 | ldata->column = 0; |
f6c8dbe6 | 1744 | ldata->minimum_to_wake = 1; |
1da177e4 | 1745 | tty->closing = 0; |
b66f4fa5 PH |
1746 | /* indicate buffer work may resume */ |
1747 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1748 | n_tty_set_termios(tty, NULL); | |
1749 | tty_unthrottle(tty); | |
70ece7a7 | 1750 | |
1da177e4 | 1751 | return 0; |
b91939f5 | 1752 | err_free_bufs: |
ba2e68ac JS |
1753 | kfree(ldata->read_buf); |
1754 | kfree(ldata->echo_buf); | |
70ece7a7 JS |
1755 | kfree(ldata); |
1756 | err: | |
b91939f5 | 1757 | return -ENOMEM; |
1da177e4 LT |
1758 | } |
1759 | ||
1760 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1761 | { | |
53c5ee2c JS |
1762 | struct n_tty_data *ldata = tty->disc_data; |
1763 | ||
53c5ee2c | 1764 | if (ldata->icanon && !L_EXTPROC(tty)) { |
a73d3d69 | 1765 | if (ldata->canon_head != ldata->read_tail) |
1da177e4 | 1766 | return 1; |
ce74117a | 1767 | } else if (read_cnt(ldata) >= (amt ? amt : 1)) |
1da177e4 LT |
1768 | return 1; |
1769 | ||
1770 | return 0; | |
1771 | } | |
1772 | ||
1773 | /** | |
bbd20759 | 1774 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1775 | * @tty: terminal device |
1776 | * @b: user data | |
1777 | * @nr: size of data | |
1778 | * | |
11a96d18 | 1779 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1780 | * ICANON is off; it copies characters straight from the tty queue to |
1781 | * user space directly. It can be profitably called twice; once to | |
1782 | * drain the space from the tail pointer to the (physical) end of the | |
1783 | * buffer, and once to drain the space from the (physical) beginning of | |
1784 | * the buffer to head pointer. | |
1785 | * | |
bddc7152 | 1786 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1787 | * |
6d76bd26 PH |
1788 | * n_tty_read()/consumer path: |
1789 | * caller holds non-exclusive termios_rwsem | |
1790 | * read_tail published | |
1da177e4 | 1791 | */ |
4edf1827 | 1792 | |
33f0f88f | 1793 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1794 | unsigned char __user **b, |
1795 | size_t *nr) | |
1796 | ||
1797 | { | |
53c5ee2c | 1798 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1799 | int retval; |
1800 | size_t n; | |
3fa10cc8 | 1801 | bool is_eof; |
bc5a5e3f | 1802 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1803 | |
1804 | retval = 0; | |
bc5a5e3f | 1805 | n = min(read_cnt(ldata), N_TTY_BUF_SIZE - tail); |
1da177e4 | 1806 | n = min(*nr, n); |
1da177e4 | 1807 | if (n) { |
bc5a5e3f | 1808 | retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
1da177e4 | 1809 | n -= retval; |
bc5a5e3f PH |
1810 | is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); |
1811 | tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, | |
53c5ee2c | 1812 | ldata->icanon); |
bc5a5e3f | 1813 | ldata->read_tail += n; |
26df6d13 | 1814 | /* Turn single EOF into zero-length read */ |
ce74117a | 1815 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !read_cnt(ldata)) |
3fa10cc8 | 1816 | n = 0; |
1da177e4 LT |
1817 | *b += n; |
1818 | *nr -= n; | |
1819 | } | |
1820 | return retval; | |
1821 | } | |
1822 | ||
88bb0de3 | 1823 | /** |
32f13521 | 1824 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1825 | * @tty: terminal device |
1826 | * @b: user data | |
1827 | * @nr: size of data | |
1828 | * | |
1829 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1830 | * it copies one line of input up to and including the line-delimiting |
1831 | * character into the user-space buffer. | |
88bb0de3 PH |
1832 | * |
1833 | * Called under the atomic_read_lock mutex | |
6d76bd26 PH |
1834 | * |
1835 | * n_tty_read()/consumer path: | |
1836 | * caller holds non-exclusive termios_rwsem | |
1837 | * read_tail published | |
88bb0de3 PH |
1838 | */ |
1839 | ||
32f13521 PH |
1840 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
1841 | unsigned char __user **b, | |
1842 | size_t *nr) | |
88bb0de3 PH |
1843 | { |
1844 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 1845 | size_t n, size, more, c; |
bc5a5e3f PH |
1846 | size_t eol; |
1847 | size_t tail; | |
1848 | int ret, found = 0; | |
88bb0de3 PH |
1849 | |
1850 | /* N.B. avoid overrun if nr == 0 */ | |
ce74117a | 1851 | n = min(*nr, read_cnt(ldata)); |
6d76bd26 | 1852 | if (!n) |
32f13521 | 1853 | return 0; |
88bb0de3 | 1854 | |
bc5a5e3f | 1855 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
1856 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
1857 | ||
bc5a5e3f | 1858 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
1859 | __func__, *nr, tail, n, size); |
1860 | ||
1861 | eol = find_next_bit(ldata->read_flags, size, tail); | |
1862 | more = n - (size - tail); | |
1863 | if (eol == N_TTY_BUF_SIZE && more) { | |
1864 | /* scan wrapped without finding set bit */ | |
1865 | eol = find_next_bit(ldata->read_flags, more, 0); | |
1866 | if (eol != more) | |
1867 | found = 1; | |
1868 | } else if (eol != size) | |
1869 | found = 1; | |
1870 | ||
1871 | size = N_TTY_BUF_SIZE - tail; | |
1872 | n = (found + eol + size) & (N_TTY_BUF_SIZE - 1); | |
1873 | c = n; | |
1874 | ||
bc5a5e3f | 1875 | if (found && read_buf(ldata, eol) == __DISABLED_CHAR) |
32f13521 PH |
1876 | n--; |
1877 | ||
bc5a5e3f | 1878 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", |
32f13521 PH |
1879 | __func__, eol, found, n, c, size, more); |
1880 | ||
32f13521 | 1881 | if (n > size) { |
bc5a5e3f | 1882 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), size); |
32f13521 PH |
1883 | if (ret) |
1884 | return -EFAULT; | |
1885 | ret = copy_to_user(*b + size, ldata->read_buf, n - size); | |
1886 | } else | |
bc5a5e3f | 1887 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
32f13521 PH |
1888 | |
1889 | if (ret) | |
1890 | return -EFAULT; | |
1891 | *b += n; | |
1892 | *nr -= n; | |
1893 | ||
a73d3d69 | 1894 | if (found) |
6d76bd26 PH |
1895 | clear_bit(eol, ldata->read_flags); |
1896 | smp_mb__after_clear_bit(); | |
1897 | ldata->read_tail += c; | |
88bb0de3 | 1898 | |
32f13521 PH |
1899 | if (found) |
1900 | tty_audit_push(tty); | |
88bb0de3 PH |
1901 | return 0; |
1902 | } | |
1903 | ||
cc4191dc | 1904 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1905 | size_t, loff_t *); |
1da177e4 LT |
1906 | |
1907 | /** | |
1908 | * job_control - check job control | |
1909 | * @tty: tty | |
1910 | * @file: file handle | |
1911 | * | |
1912 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1913 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1914 | * error code if action should be taken. |
04f378b1 | 1915 | * |
01a5e440 PH |
1916 | * Locking: redirected write test is safe |
1917 | * current->signal->tty check is safe | |
1918 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 1919 | */ |
4edf1827 | 1920 | |
1da177e4 LT |
1921 | static int job_control(struct tty_struct *tty, struct file *file) |
1922 | { | |
1923 | /* Job control check -- must be done at start and after | |
1924 | every sleep (POSIX.1 7.1.1.4). */ | |
1925 | /* NOTE: not yet done after every sleep pending a thorough | |
1926 | check of the logic of this change. -- jlc */ | |
1927 | /* don't stop on /dev/console */ | |
01a5e440 PH |
1928 | if (file->f_op->write == redirected_tty_write || |
1929 | current->signal->tty != tty) | |
1930 | return 0; | |
1931 | ||
1932 | spin_lock_irq(&tty->ctrl_lock); | |
1933 | if (!tty->pgrp) | |
1934 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
1935 | else if (task_pgrp(current) != tty->pgrp) { | |
1936 | spin_unlock_irq(&tty->ctrl_lock); | |
1937 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
1938 | return -EIO; | |
1939 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
1940 | set_thread_flag(TIF_SIGPENDING); | |
1941 | return -ERESTARTSYS; | |
1da177e4 | 1942 | } |
01a5e440 | 1943 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
1944 | return 0; |
1945 | } | |
4edf1827 | 1946 | |
1da177e4 LT |
1947 | |
1948 | /** | |
11a96d18 | 1949 | * n_tty_read - read function for tty |
1da177e4 LT |
1950 | * @tty: tty device |
1951 | * @file: file object | |
1952 | * @buf: userspace buffer pointer | |
1953 | * @nr: size of I/O | |
1954 | * | |
1955 | * Perform reads for the line discipline. We are guaranteed that the | |
1956 | * line discipline will not be closed under us but we may get multiple | |
1957 | * parallel readers and must handle this ourselves. We may also get | |
1958 | * a hangup. Always called in user context, may sleep. | |
1959 | * | |
1960 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
1961 | * |
1962 | * n_tty_read()/consumer path: | |
1963 | * claims non-exclusive termios_rwsem | |
1964 | * publishes read_tail | |
1da177e4 | 1965 | */ |
4edf1827 | 1966 | |
11a96d18 | 1967 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1968 | unsigned char __user *buf, size_t nr) |
1969 | { | |
53c5ee2c | 1970 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1971 | unsigned char __user *b = buf; |
1972 | DECLARE_WAITQUEUE(wait, current); | |
1973 | int c; | |
1974 | int minimum, time; | |
1975 | ssize_t retval = 0; | |
1976 | ssize_t size; | |
1977 | long timeout; | |
1978 | unsigned long flags; | |
04f378b1 | 1979 | int packet; |
1da177e4 LT |
1980 | |
1981 | do_it_again: | |
1da177e4 | 1982 | c = job_control(tty, file); |
4edf1827 | 1983 | if (c < 0) |
1da177e4 | 1984 | return c; |
4edf1827 | 1985 | |
9356b535 PH |
1986 | down_read(&tty->termios_rwsem); |
1987 | ||
1da177e4 LT |
1988 | minimum = time = 0; |
1989 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 1990 | if (!ldata->icanon) { |
1da177e4 LT |
1991 | minimum = MIN_CHAR(tty); |
1992 | if (minimum) { | |
a6e54319 | 1993 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 1994 | if (time) |
f6c8dbe6 | 1995 | ldata->minimum_to_wake = 1; |
1da177e4 | 1996 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
1997 | (ldata->minimum_to_wake > minimum)) |
1998 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 1999 | } else { |
a6e54319 | 2000 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2001 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2002 | } |
2003 | } | |
2004 | ||
2005 | /* | |
2006 | * Internal serialization of reads. | |
2007 | */ | |
2008 | if (file->f_flags & O_NONBLOCK) { | |
9356b535 PH |
2009 | if (!mutex_trylock(&ldata->atomic_read_lock)) { |
2010 | up_read(&tty->termios_rwsem); | |
1da177e4 | 2011 | return -EAGAIN; |
9356b535 | 2012 | } |
4edf1827 | 2013 | } else { |
9356b535 PH |
2014 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) { |
2015 | up_read(&tty->termios_rwsem); | |
1da177e4 | 2016 | return -ERESTARTSYS; |
9356b535 | 2017 | } |
1da177e4 | 2018 | } |
04f378b1 | 2019 | packet = tty->packet; |
1da177e4 LT |
2020 | |
2021 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2022 | while (nr) { |
2023 | /* First test for status change. */ | |
04f378b1 | 2024 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2025 | unsigned char cs; |
2026 | if (b != buf) | |
2027 | break; | |
04f378b1 | 2028 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
2029 | cs = tty->link->ctrl_status; |
2030 | tty->link->ctrl_status = 0; | |
04f378b1 | 2031 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 2032 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2033 | retval = -EFAULT; |
2034 | b--; | |
2035 | break; | |
2036 | } | |
2037 | nr--; | |
2038 | break; | |
2039 | } | |
2040 | /* This statement must be first before checking for input | |
2041 | so that any interrupt will set the state back to | |
2042 | TASK_RUNNING. */ | |
2043 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 2044 | |
f6c8dbe6 | 2045 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2046 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2047 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2048 | |
1da177e4 LT |
2049 | if (!input_available_p(tty, 0)) { |
2050 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
2051 | retval = -EIO; | |
2052 | break; | |
2053 | } | |
2054 | if (tty_hung_up_p(file)) | |
2055 | break; | |
2056 | if (!timeout) | |
2057 | break; | |
2058 | if (file->f_flags & O_NONBLOCK) { | |
2059 | retval = -EAGAIN; | |
2060 | break; | |
2061 | } | |
2062 | if (signal_pending(current)) { | |
2063 | retval = -ERESTARTSYS; | |
2064 | break; | |
2065 | } | |
55db4c64 | 2066 | n_tty_set_room(tty); |
9356b535 PH |
2067 | up_read(&tty->termios_rwsem); |
2068 | ||
1da177e4 | 2069 | timeout = schedule_timeout(timeout); |
9356b535 PH |
2070 | |
2071 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2072 | continue; |
2073 | } | |
2074 | __set_current_state(TASK_RUNNING); | |
2075 | ||
2076 | /* Deal with packet mode. */ | |
04f378b1 | 2077 | if (packet && b == buf) { |
522ed776 | 2078 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
2079 | retval = -EFAULT; |
2080 | b--; | |
2081 | break; | |
2082 | } | |
2083 | nr--; | |
2084 | } | |
2085 | ||
53c5ee2c | 2086 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2087 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
1da177e4 LT |
2088 | if (retval) |
2089 | break; | |
2090 | } else { | |
2091 | int uncopied; | |
04f378b1 AC |
2092 | /* The copy function takes the read lock and handles |
2093 | locking internally for this case */ | |
1da177e4 LT |
2094 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2095 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2096 | if (uncopied) { | |
2097 | retval = -EFAULT; | |
2098 | break; | |
2099 | } | |
2100 | } | |
2101 | ||
6367ca72 | 2102 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2103 | |
2104 | if (b - buf >= minimum) | |
2105 | break; | |
2106 | if (time) | |
2107 | timeout = time; | |
2108 | } | |
bddc7152 | 2109 | mutex_unlock(&ldata->atomic_read_lock); |
1da177e4 LT |
2110 | remove_wait_queue(&tty->read_wait, &wait); |
2111 | ||
2112 | if (!waitqueue_active(&tty->read_wait)) | |
f6c8dbe6 | 2113 | ldata->minimum_to_wake = minimum; |
1da177e4 LT |
2114 | |
2115 | __set_current_state(TASK_RUNNING); | |
2116 | size = b - buf; | |
2117 | if (size) { | |
2118 | retval = size; | |
2119 | if (nr) | |
4edf1827 | 2120 | clear_bit(TTY_PUSH, &tty->flags); |
9356b535 PH |
2121 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) { |
2122 | up_read(&tty->termios_rwsem); | |
bbd20759 | 2123 | goto do_it_again; |
9356b535 | 2124 | } |
1da177e4 | 2125 | |
55db4c64 | 2126 | n_tty_set_room(tty); |
9356b535 | 2127 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2128 | return retval; |
2129 | } | |
2130 | ||
2131 | /** | |
11a96d18 | 2132 | * n_tty_write - write function for tty |
1da177e4 LT |
2133 | * @tty: tty device |
2134 | * @file: file object | |
2135 | * @buf: userspace buffer pointer | |
2136 | * @nr: size of I/O | |
2137 | * | |
a88a69c9 | 2138 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2139 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2140 | * and other such events. Since the receive code will echo characters, |
2141 | * thus calling driver write methods, the output_lock is used in | |
2142 | * the output processing functions called here as well as in the | |
2143 | * echo processing function to protect the column state and space | |
2144 | * left in the buffer. | |
1da177e4 LT |
2145 | * |
2146 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2147 | * |
2148 | * Locking: output_lock to protect column state and space left | |
2149 | * (note that the process_output*() functions take this | |
2150 | * lock themselves) | |
1da177e4 | 2151 | */ |
4edf1827 | 2152 | |
11a96d18 | 2153 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2154 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2155 | { |
2156 | const unsigned char *b = buf; | |
2157 | DECLARE_WAITQUEUE(wait, current); | |
2158 | int c; | |
2159 | ssize_t retval = 0; | |
2160 | ||
2161 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2162 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2163 | retval = tty_check_change(tty); | |
2164 | if (retval) | |
2165 | return retval; | |
2166 | } | |
2167 | ||
9356b535 PH |
2168 | down_read(&tty->termios_rwsem); |
2169 | ||
a88a69c9 JP |
2170 | /* Write out any echoed characters that are still pending */ |
2171 | process_echoes(tty); | |
300a6204 | 2172 | |
1da177e4 LT |
2173 | add_wait_queue(&tty->write_wait, &wait); |
2174 | while (1) { | |
2175 | set_current_state(TASK_INTERRUPTIBLE); | |
2176 | if (signal_pending(current)) { | |
2177 | retval = -ERESTARTSYS; | |
2178 | break; | |
2179 | } | |
2180 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2181 | retval = -EIO; | |
2182 | break; | |
2183 | } | |
582f5590 | 2184 | if (O_OPOST(tty)) { |
1da177e4 | 2185 | while (nr > 0) { |
a88a69c9 | 2186 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2187 | if (num < 0) { |
2188 | if (num == -EAGAIN) | |
2189 | break; | |
2190 | retval = num; | |
2191 | goto break_out; | |
2192 | } | |
2193 | b += num; | |
2194 | nr -= num; | |
2195 | if (nr == 0) | |
2196 | break; | |
2197 | c = *b; | |
a88a69c9 | 2198 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2199 | break; |
2200 | b++; nr--; | |
2201 | } | |
f34d7a5b AC |
2202 | if (tty->ops->flush_chars) |
2203 | tty->ops->flush_chars(tty); | |
1da177e4 | 2204 | } else { |
d6afe27b | 2205 | while (nr > 0) { |
f34d7a5b | 2206 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
2207 | if (c < 0) { |
2208 | retval = c; | |
2209 | goto break_out; | |
2210 | } | |
2211 | if (!c) | |
2212 | break; | |
2213 | b += c; | |
2214 | nr -= c; | |
1da177e4 | 2215 | } |
1da177e4 LT |
2216 | } |
2217 | if (!nr) | |
2218 | break; | |
2219 | if (file->f_flags & O_NONBLOCK) { | |
2220 | retval = -EAGAIN; | |
2221 | break; | |
2222 | } | |
9356b535 PH |
2223 | up_read(&tty->termios_rwsem); |
2224 | ||
1da177e4 | 2225 | schedule(); |
9356b535 PH |
2226 | |
2227 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2228 | } |
2229 | break_out: | |
2230 | __set_current_state(TASK_RUNNING); | |
2231 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2232 | if (b - buf != nr && tty->fasync) |
2233 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2234 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2235 | return (b - buf) ? b - buf : retval; |
2236 | } | |
2237 | ||
2238 | /** | |
11a96d18 | 2239 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2240 | * @tty: terminal device |
2241 | * @file: file accessing it | |
2242 | * @wait: poll table | |
2243 | * | |
2244 | * Called when the line discipline is asked to poll() for data or | |
2245 | * for special events. This code is not serialized with respect to | |
2246 | * other events save open/close. | |
2247 | * | |
2248 | * This code must be sure never to sleep through a hangup. | |
2249 | * Called without the kernel lock held - fine | |
1da177e4 | 2250 | */ |
4edf1827 | 2251 | |
11a96d18 | 2252 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2253 | poll_table *wait) |
1da177e4 | 2254 | { |
f6c8dbe6 | 2255 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2256 | unsigned int mask = 0; |
2257 | ||
2258 | poll_wait(file, &tty->read_wait, wait); | |
2259 | poll_wait(file, &tty->write_wait, wait); | |
2260 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2261 | mask |= POLLIN | POLLRDNORM; | |
2262 | if (tty->packet && tty->link->ctrl_status) | |
2263 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2264 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2265 | mask |= POLLHUP; | |
2266 | if (tty_hung_up_p(file)) | |
2267 | mask |= POLLHUP; | |
2268 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2269 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2270 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2271 | else |
f6c8dbe6 | 2272 | ldata->minimum_to_wake = 1; |
1da177e4 | 2273 | } |
f34d7a5b AC |
2274 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2275 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2276 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2277 | mask |= POLLOUT | POLLWRNORM; |
2278 | return mask; | |
2279 | } | |
2280 | ||
57c94121 | 2281 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2282 | { |
bc5a5e3f | 2283 | size_t nr, head, tail; |
47afa7a5 | 2284 | |
a73d3d69 | 2285 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2286 | return 0; |
ba2e68ac JS |
2287 | head = ldata->canon_head; |
2288 | tail = ldata->read_tail; | |
bc5a5e3f | 2289 | nr = head - tail; |
47afa7a5 AC |
2290 | /* Skip EOF-chars.. */ |
2291 | while (head != tail) { | |
bc5a5e3f PH |
2292 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2293 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2294 | nr--; |
bc5a5e3f | 2295 | tail++; |
47afa7a5 AC |
2296 | } |
2297 | return nr; | |
2298 | } | |
2299 | ||
2300 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2301 | unsigned int cmd, unsigned long arg) | |
2302 | { | |
ba2e68ac | 2303 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2304 | int retval; |
2305 | ||
2306 | switch (cmd) { | |
2307 | case TIOCOUTQ: | |
2308 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2309 | case TIOCINQ: | |
6d76bd26 | 2310 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2311 | if (L_ICANON(tty)) |
57c94121 | 2312 | retval = inq_canon(ldata); |
6d76bd26 PH |
2313 | else |
2314 | retval = read_cnt(ldata); | |
2315 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2316 | return put_user(retval, (unsigned int __user *) arg); |
2317 | default: | |
2318 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2319 | } | |
2320 | } | |
2321 | ||
f6c8dbe6 PH |
2322 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2323 | { | |
2324 | struct n_tty_data *ldata = tty->disc_data; | |
2325 | ||
2326 | if (!waitqueue_active(&tty->read_wait)) { | |
2327 | if (on) | |
2328 | ldata->minimum_to_wake = 1; | |
2329 | else if (!tty->fasync) | |
2330 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2331 | } | |
2332 | } | |
2333 | ||
a352def2 | 2334 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2335 | .magic = TTY_LDISC_MAGIC, |
2336 | .name = "n_tty", | |
2337 | .open = n_tty_open, | |
2338 | .close = n_tty_close, | |
2339 | .flush_buffer = n_tty_flush_buffer, | |
2340 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2341 | .read = n_tty_read, |
2342 | .write = n_tty_write, | |
e10cc1df PF |
2343 | .ioctl = n_tty_ioctl, |
2344 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2345 | .poll = n_tty_poll, |
e10cc1df | 2346 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2347 | .write_wakeup = n_tty_write_wakeup, |
2348 | .fasync = n_tty_fasync, | |
24a89d1c | 2349 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2350 | }; |
572b9adb RG |
2351 | |
2352 | /** | |
2353 | * n_tty_inherit_ops - inherit N_TTY methods | |
2354 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2355 | * | |
593fb1ae | 2356 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2357 | * methods. |
2358 | */ | |
2359 | ||
2360 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2361 | { | |
2362 | *ops = tty_ldisc_N_TTY; | |
2363 | ops->owner = NULL; | |
2364 | ops->refcount = ops->flags = 0; | |
2365 | } | |
2366 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |