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 | 98 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
3fe780b3 | 99 | |
fb7aa03d PH |
100 | /* shared by producer and consumer */ |
101 | char *read_buf; | |
3fe780b3 | 102 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
ba2e68ac | 103 | |
f6c8dbe6 | 104 | int minimum_to_wake; |
ba2e68ac | 105 | |
fb7aa03d PH |
106 | /* consumer-published */ |
107 | size_t read_tail; | |
108 | ||
109 | /* protected by echo_lock */ | |
ba2e68ac JS |
110 | unsigned char *echo_buf; |
111 | unsigned int echo_pos; | |
112 | unsigned int echo_cnt; | |
113 | ||
fb7aa03d PH |
114 | /* protected by output lock */ |
115 | unsigned int column; | |
ba2e68ac | 116 | unsigned int canon_column; |
bddc7152 JS |
117 | |
118 | struct mutex atomic_read_lock; | |
119 | struct mutex output_lock; | |
120 | struct mutex echo_lock; | |
70ece7a7 JS |
121 | }; |
122 | ||
ce74117a PH |
123 | static inline size_t read_cnt(struct n_tty_data *ldata) |
124 | { | |
a2f73be8 | 125 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
126 | } |
127 | ||
bc5a5e3f PH |
128 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
129 | { | |
130 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
131 | } | |
132 | ||
133 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
134 | { | |
135 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
136 | } | |
137 | ||
522ed776 MT |
138 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
139 | unsigned char __user *ptr) | |
140 | { | |
53c5ee2c JS |
141 | struct n_tty_data *ldata = tty->disc_data; |
142 | ||
143 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
144 | return put_user(x, ptr); |
145 | } | |
146 | ||
24a89d1c | 147 | static int receive_room(struct tty_struct *tty) |
55db4c64 | 148 | { |
53c5ee2c | 149 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 150 | int left; |
55db4c64 | 151 | |
090abf7b JA |
152 | if (I_PARMRK(tty)) { |
153 | /* Multiply read_cnt by 3, since each byte might take up to | |
154 | * three times as many spaces when PARMRK is set (depending on | |
155 | * its flags, e.g. parity error). */ | |
ce74117a | 156 | left = N_TTY_BUF_SIZE - read_cnt(ldata) * 3 - 1; |
090abf7b | 157 | } else |
ce74117a | 158 | left = N_TTY_BUF_SIZE - read_cnt(ldata) - 1; |
090abf7b | 159 | |
55db4c64 LT |
160 | /* |
161 | * If we are doing input canonicalization, and there are no | |
162 | * pending newlines, let characters through without limit, so | |
163 | * that erase characters will be handled. Other excess | |
164 | * characters will be beeped. | |
165 | */ | |
166 | if (left <= 0) | |
a73d3d69 | 167 | left = ldata->icanon && ldata->canon_head == ldata->read_tail; |
55db4c64 | 168 | |
24a89d1c | 169 | return left; |
7879a9f9 PH |
170 | } |
171 | ||
24a89d1c PH |
172 | /** |
173 | * n_tty_set_room - receive space | |
174 | * @tty: terminal | |
175 | * | |
176 | * Re-schedules the flip buffer work if space just became available. | |
177 | * | |
6d76bd26 PH |
178 | * Caller holds exclusive termios_rwsem |
179 | * or | |
180 | * n_tty_read()/consumer path: | |
181 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
182 | */ |
183 | ||
7879a9f9 PH |
184 | static void n_tty_set_room(struct tty_struct *tty) |
185 | { | |
24a89d1c PH |
186 | struct n_tty_data *ldata = tty->disc_data; |
187 | ||
55db4c64 | 188 | /* Did this open up the receive buffer? We may need to flip */ |
24a89d1c PH |
189 | if (unlikely(ldata->no_room) && receive_room(tty)) { |
190 | ldata->no_room = 0; | |
191 | ||
ecbbfd44 | 192 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 193 | "scheduling with invalid itty\n"); |
21622939 PH |
194 | /* see if ldisc has been killed - if so, this means that |
195 | * even though the ldisc has been halted and ->buf.work | |
196 | * cancelled, ->buf.work is about to be rescheduled | |
197 | */ | |
198 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
199 | "scheduling buffer work for halted ldisc\n"); | |
f0f947c1 | 200 | queue_work(system_unbound_wq, &tty->port->buf.work); |
ecbbfd44 | 201 | } |
55db4c64 LT |
202 | } |
203 | ||
9a4aec2d PH |
204 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
205 | { | |
206 | struct n_tty_data *ldata = tty->disc_data; | |
207 | ssize_t n = 0; | |
208 | ||
209 | if (!ldata->icanon) | |
210 | n = read_cnt(ldata); | |
211 | else | |
212 | n = ldata->canon_head - ldata->read_tail; | |
213 | return n; | |
214 | } | |
215 | ||
ee0bab83 PH |
216 | /** |
217 | * n_tty_write_wakeup - asynchronous I/O notifier | |
218 | * @tty: tty device | |
219 | * | |
220 | * Required for the ptys, serial driver etc. since processes | |
221 | * that attach themselves to the master and rely on ASYNC | |
222 | * IO must be woken up | |
223 | */ | |
224 | ||
225 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
226 | { | |
227 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) | |
228 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
229 | } | |
230 | ||
6367ca72 PH |
231 | static inline void n_tty_check_throttle(struct tty_struct *tty) |
232 | { | |
3afb1b39 PH |
233 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) |
234 | return; | |
6367ca72 PH |
235 | /* |
236 | * Check the remaining room for the input canonicalization | |
237 | * mode. We don't want to throttle the driver if we're in | |
238 | * canonical mode and don't have a newline yet! | |
239 | */ | |
240 | while (1) { | |
241 | int throttled; | |
242 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
243 | if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) | |
244 | break; | |
245 | throttled = tty_throttle_safe(tty); | |
246 | if (!throttled) | |
247 | break; | |
248 | } | |
249 | __tty_set_flow_change(tty, 0); | |
250 | } | |
251 | ||
252 | static inline void n_tty_check_unthrottle(struct tty_struct *tty) | |
253 | { | |
3afb1b39 PH |
254 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
255 | tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { | |
256 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
257 | return; | |
258 | if (!tty->count) | |
259 | return; | |
260 | n_tty_set_room(tty); | |
261 | n_tty_write_wakeup(tty->link); | |
262 | wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); | |
263 | return; | |
264 | } | |
265 | ||
6367ca72 PH |
266 | /* If there is enough space in the read buffer now, let the |
267 | * low-level driver know. We use chars_in_buffer() to | |
268 | * check the buffer, as it now knows about canonical mode. | |
269 | * Otherwise, if the driver is throttled and the line is | |
270 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
271 | * we won't get any more characters. | |
272 | */ | |
273 | ||
274 | while (1) { | |
275 | int unthrottled; | |
276 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
277 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
278 | break; | |
279 | if (!tty->count) | |
280 | break; | |
281 | n_tty_set_room(tty); | |
282 | unthrottled = tty_unthrottle_safe(tty); | |
283 | if (!unthrottled) | |
284 | break; | |
285 | } | |
286 | __tty_set_flow_change(tty, 0); | |
287 | } | |
288 | ||
17b82060 AC |
289 | /** |
290 | * put_tty_queue - add character to tty | |
291 | * @c: character | |
57c94121 | 292 | * @ldata: n_tty data |
17b82060 | 293 | * |
6d76bd26 PH |
294 | * Add a character to the tty read_buf queue. |
295 | * | |
296 | * n_tty_receive_buf()/producer path: | |
297 | * caller holds non-exclusive termios_rwsem | |
298 | * modifies read_head | |
299 | * | |
300 | * read_head is only considered 'published' if canonical mode is | |
301 | * not active. | |
17b82060 AC |
302 | */ |
303 | ||
57c94121 | 304 | static void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 305 | { |
6d76bd26 PH |
306 | if (read_cnt(ldata) < N_TTY_BUF_SIZE) { |
307 | *read_buf_addr(ldata, ldata->read_head) = c; | |
308 | ldata->read_head++; | |
309 | } | |
1da177e4 LT |
310 | } |
311 | ||
1da177e4 LT |
312 | /** |
313 | * reset_buffer_flags - reset buffer state | |
314 | * @tty: terminal to reset | |
315 | * | |
25518c68 PH |
316 | * Reset the read buffer counters and clear the flags. |
317 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 318 | * |
6d76bd26 PH |
319 | * Locking: caller holds exclusive termios_rwsem |
320 | * (or locking is not required) | |
1da177e4 | 321 | */ |
a88a69c9 | 322 | |
b66f4fa5 | 323 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 324 | { |
a73d3d69 | 325 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
a88a69c9 | 326 | |
bddc7152 | 327 | mutex_lock(&ldata->echo_lock); |
ae56f330 | 328 | ldata->echo_pos = ldata->echo_cnt = 0; |
bddc7152 | 329 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 | 330 | |
a73d3d69 | 331 | ldata->erasing = 0; |
3fe780b3 | 332 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
1da177e4 LT |
333 | } |
334 | ||
a30737ab PH |
335 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
336 | { | |
337 | unsigned long flags; | |
338 | ||
339 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
340 | if (tty->link->packet) { | |
341 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
342 | wake_up_interruptible(&tty->link->read_wait); | |
343 | } | |
344 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
345 | } | |
346 | ||
1da177e4 LT |
347 | /** |
348 | * n_tty_flush_buffer - clean input queue | |
349 | * @tty: terminal device | |
350 | * | |
25518c68 PH |
351 | * Flush the input buffer. Called when the tty layer wants the |
352 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
353 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 354 | * |
6d76bd26 PH |
355 | * Holds termios_rwsem to exclude producer/consumer while |
356 | * buffer indices are reset. | |
357 | * | |
358 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 359 | */ |
4edf1827 AC |
360 | |
361 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 362 | { |
6d76bd26 | 363 | down_write(&tty->termios_rwsem); |
b66f4fa5 PH |
364 | reset_buffer_flags(tty->disc_data); |
365 | n_tty_set_room(tty); | |
4edf1827 | 366 | |
a30737ab PH |
367 | if (tty->link) |
368 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 369 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
370 | } |
371 | ||
6d76bd26 PH |
372 | /** |
373 | * n_tty_chars_in_buffer - report available bytes | |
374 | * @tty: tty device | |
375 | * | |
376 | * Report the number of characters buffered to be delivered to user | |
377 | * at this instant in time. | |
378 | * | |
379 | * Locking: exclusive termios_rwsem | |
380 | */ | |
381 | ||
a19d0c6a PH |
382 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
383 | { | |
6d76bd26 PH |
384 | ssize_t n; |
385 | ||
47534084 | 386 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
6d76bd26 PH |
387 | |
388 | down_write(&tty->termios_rwsem); | |
389 | n = chars_in_buffer(tty); | |
390 | up_write(&tty->termios_rwsem); | |
391 | return n; | |
a19d0c6a PH |
392 | } |
393 | ||
1da177e4 LT |
394 | /** |
395 | * is_utf8_continuation - utf8 multibyte check | |
396 | * @c: byte to check | |
397 | * | |
398 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
399 | * character. We use this to correctly compute the on screen size | |
400 | * of the character when printing | |
401 | */ | |
4edf1827 | 402 | |
1da177e4 LT |
403 | static inline int is_utf8_continuation(unsigned char c) |
404 | { | |
405 | return (c & 0xc0) == 0x80; | |
406 | } | |
407 | ||
408 | /** | |
409 | * is_continuation - multibyte check | |
410 | * @c: byte to check | |
411 | * | |
412 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
413 | * character and the terminal is in unicode mode. | |
414 | */ | |
4edf1827 | 415 | |
1da177e4 LT |
416 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
417 | { | |
418 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
419 | } | |
420 | ||
421 | /** | |
a88a69c9 | 422 | * do_output_char - output one character |
1da177e4 LT |
423 | * @c: character (or partial unicode symbol) |
424 | * @tty: terminal device | |
a88a69c9 | 425 | * @space: space available in tty driver write buffer |
1da177e4 | 426 | * |
a88a69c9 JP |
427 | * This is a helper function that handles one output character |
428 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
429 | * doing OPOST processing and putting the results in the |
430 | * tty driver's write buffer. | |
a88a69c9 JP |
431 | * |
432 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
433 | * and NLDLY. They simply aren't relevant in the world today. | |
434 | * If you ever need them, add them here. | |
1da177e4 | 435 | * |
a88a69c9 JP |
436 | * Returns the number of bytes of buffer space used or -1 if |
437 | * no space left. | |
438 | * | |
439 | * Locking: should be called under the output_lock to protect | |
440 | * the column state and space left in the buffer | |
1da177e4 | 441 | */ |
4edf1827 | 442 | |
a88a69c9 | 443 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 444 | { |
53c5ee2c | 445 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 446 | int spaces; |
1da177e4 | 447 | |
1da177e4 LT |
448 | if (!space) |
449 | return -1; | |
300a6204 | 450 | |
a88a69c9 JP |
451 | switch (c) { |
452 | case '\n': | |
453 | if (O_ONLRET(tty)) | |
53c5ee2c | 454 | ldata->column = 0; |
a88a69c9 JP |
455 | if (O_ONLCR(tty)) { |
456 | if (space < 2) | |
457 | return -1; | |
ba2e68ac | 458 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 459 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
460 | return 2; |
461 | } | |
ba2e68ac | 462 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
463 | break; |
464 | case '\r': | |
53c5ee2c | 465 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
466 | return 0; |
467 | if (O_OCRNL(tty)) { | |
468 | c = '\n'; | |
469 | if (O_ONLRET(tty)) | |
ba2e68ac | 470 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 471 | break; |
a88a69c9 | 472 | } |
ba2e68ac | 473 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
474 | break; |
475 | case '\t': | |
53c5ee2c | 476 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
477 | if (O_TABDLY(tty) == XTABS) { |
478 | if (space < spaces) | |
479 | return -1; | |
53c5ee2c | 480 | ldata->column += spaces; |
a88a69c9 JP |
481 | tty->ops->write(tty, " ", spaces); |
482 | return spaces; | |
1da177e4 | 483 | } |
53c5ee2c | 484 | ldata->column += spaces; |
a88a69c9 JP |
485 | break; |
486 | case '\b': | |
53c5ee2c JS |
487 | if (ldata->column > 0) |
488 | ldata->column--; | |
a88a69c9 JP |
489 | break; |
490 | default: | |
a59c0d6f JP |
491 | if (!iscntrl(c)) { |
492 | if (O_OLCUC(tty)) | |
493 | c = toupper(c); | |
494 | if (!is_continuation(c, tty)) | |
53c5ee2c | 495 | ldata->column++; |
a59c0d6f | 496 | } |
a88a69c9 | 497 | break; |
1da177e4 | 498 | } |
a88a69c9 | 499 | |
f34d7a5b | 500 | tty_put_char(tty, c); |
a88a69c9 JP |
501 | return 1; |
502 | } | |
503 | ||
504 | /** | |
505 | * process_output - output post processor | |
506 | * @c: character (or partial unicode symbol) | |
507 | * @tty: terminal device | |
508 | * | |
ee5aa7b8 JP |
509 | * Output one character with OPOST processing. |
510 | * Returns -1 when the output device is full and the character | |
511 | * must be retried. | |
a88a69c9 JP |
512 | * |
513 | * Locking: output_lock to protect column state and space left | |
514 | * (also, this is called from n_tty_write under the | |
515 | * tty layer write lock) | |
516 | */ | |
517 | ||
518 | static int process_output(unsigned char c, struct tty_struct *tty) | |
519 | { | |
bddc7152 | 520 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
521 | int space, retval; |
522 | ||
bddc7152 | 523 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
524 | |
525 | space = tty_write_room(tty); | |
526 | retval = do_output_char(c, tty, space); | |
527 | ||
bddc7152 | 528 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
529 | if (retval < 0) |
530 | return -1; | |
531 | else | |
532 | return 0; | |
1da177e4 LT |
533 | } |
534 | ||
535 | /** | |
a88a69c9 | 536 | * process_output_block - block post processor |
1da177e4 | 537 | * @tty: terminal device |
ee5aa7b8 JP |
538 | * @buf: character buffer |
539 | * @nr: number of bytes to output | |
540 | * | |
541 | * Output a block of characters with OPOST processing. | |
542 | * Returns the number of characters output. | |
1da177e4 LT |
543 | * |
544 | * This path is used to speed up block console writes, among other | |
545 | * things when processing blocks of output data. It handles only | |
546 | * the simple cases normally found and helps to generate blocks of | |
547 | * symbols for the console driver and thus improve performance. | |
548 | * | |
a88a69c9 JP |
549 | * Locking: output_lock to protect column state and space left |
550 | * (also, this is called from n_tty_write under the | |
551 | * tty layer write lock) | |
1da177e4 | 552 | */ |
4edf1827 | 553 | |
a88a69c9 JP |
554 | static ssize_t process_output_block(struct tty_struct *tty, |
555 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 556 | { |
53c5ee2c | 557 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 558 | int space; |
bbd20759 | 559 | int i; |
1da177e4 LT |
560 | const unsigned char *cp; |
561 | ||
bddc7152 | 562 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 563 | |
f34d7a5b | 564 | space = tty_write_room(tty); |
300a6204 | 565 | if (!space) { |
bddc7152 | 566 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 567 | return 0; |
a88a69c9 | 568 | } |
1da177e4 LT |
569 | if (nr > space) |
570 | nr = space; | |
571 | ||
572 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
573 | unsigned char c = *cp; |
574 | ||
575 | switch (c) { | |
1da177e4 LT |
576 | case '\n': |
577 | if (O_ONLRET(tty)) | |
53c5ee2c | 578 | ldata->column = 0; |
1da177e4 LT |
579 | if (O_ONLCR(tty)) |
580 | goto break_out; | |
ba2e68ac | 581 | ldata->canon_column = ldata->column; |
1da177e4 LT |
582 | break; |
583 | case '\r': | |
53c5ee2c | 584 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
585 | goto break_out; |
586 | if (O_OCRNL(tty)) | |
587 | goto break_out; | |
ba2e68ac | 588 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
589 | break; |
590 | case '\t': | |
591 | goto break_out; | |
592 | case '\b': | |
53c5ee2c JS |
593 | if (ldata->column > 0) |
594 | ldata->column--; | |
1da177e4 LT |
595 | break; |
596 | default: | |
a59c0d6f JP |
597 | if (!iscntrl(c)) { |
598 | if (O_OLCUC(tty)) | |
599 | goto break_out; | |
600 | if (!is_continuation(c, tty)) | |
53c5ee2c | 601 | ldata->column++; |
a59c0d6f | 602 | } |
1da177e4 LT |
603 | break; |
604 | } | |
605 | } | |
606 | break_out: | |
f34d7a5b | 607 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 608 | |
bddc7152 | 609 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
610 | return i; |
611 | } | |
612 | ||
a88a69c9 JP |
613 | /** |
614 | * process_echoes - write pending echo characters | |
615 | * @tty: terminal device | |
616 | * | |
617 | * Write previously buffered echo (and other ldisc-generated) | |
618 | * characters to the tty. | |
619 | * | |
620 | * Characters generated by the ldisc (including echoes) need to | |
621 | * be buffered because the driver's write buffer can fill during | |
622 | * heavy program output. Echoing straight to the driver will | |
623 | * often fail under these conditions, causing lost characters and | |
624 | * resulting mismatches of ldisc state information. | |
625 | * | |
626 | * Since the ldisc state must represent the characters actually sent | |
627 | * to the driver at the time of the write, operations like certain | |
628 | * changes in column state are also saved in the buffer and executed | |
629 | * here. | |
630 | * | |
631 | * A circular fifo buffer is used so that the most recent characters | |
632 | * are prioritized. Also, when control characters are echoed with a | |
633 | * prefixed "^", the pair is treated atomically and thus not separated. | |
634 | * | |
635 | * Locking: output_lock to protect column state and space left, | |
636 | * echo_lock to protect the echo buffer | |
637 | */ | |
638 | ||
639 | static void process_echoes(struct tty_struct *tty) | |
640 | { | |
53c5ee2c | 641 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
642 | int space, nr; |
643 | unsigned char c; | |
644 | unsigned char *cp, *buf_end; | |
645 | ||
ba2e68ac | 646 | if (!ldata->echo_cnt) |
a88a69c9 JP |
647 | return; |
648 | ||
bddc7152 JS |
649 | mutex_lock(&ldata->output_lock); |
650 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
651 | |
652 | space = tty_write_room(tty); | |
653 | ||
ba2e68ac JS |
654 | buf_end = ldata->echo_buf + N_TTY_BUF_SIZE; |
655 | cp = ldata->echo_buf + ldata->echo_pos; | |
656 | nr = ldata->echo_cnt; | |
a88a69c9 JP |
657 | while (nr > 0) { |
658 | c = *cp; | |
659 | if (c == ECHO_OP_START) { | |
660 | unsigned char op; | |
661 | unsigned char *opp; | |
662 | int no_space_left = 0; | |
663 | ||
664 | /* | |
665 | * If the buffer byte is the start of a multi-byte | |
666 | * operation, get the next byte, which is either the | |
667 | * op code or a control character value. | |
668 | */ | |
669 | opp = cp + 1; | |
670 | if (opp == buf_end) | |
671 | opp -= N_TTY_BUF_SIZE; | |
672 | op = *opp; | |
300a6204 | 673 | |
a88a69c9 JP |
674 | switch (op) { |
675 | unsigned int num_chars, num_bs; | |
676 | ||
677 | case ECHO_OP_ERASE_TAB: | |
678 | if (++opp == buf_end) | |
679 | opp -= N_TTY_BUF_SIZE; | |
680 | num_chars = *opp; | |
681 | ||
682 | /* | |
683 | * Determine how many columns to go back | |
684 | * in order to erase the tab. | |
685 | * This depends on the number of columns | |
686 | * used by other characters within the tab | |
687 | * area. If this (modulo 8) count is from | |
688 | * the start of input rather than from a | |
689 | * previous tab, we offset by canon column. | |
690 | * Otherwise, tab spacing is normal. | |
691 | */ | |
692 | if (!(num_chars & 0x80)) | |
ba2e68ac | 693 | num_chars += ldata->canon_column; |
a88a69c9 JP |
694 | num_bs = 8 - (num_chars & 7); |
695 | ||
696 | if (num_bs > space) { | |
697 | no_space_left = 1; | |
698 | break; | |
699 | } | |
700 | space -= num_bs; | |
701 | while (num_bs--) { | |
702 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
703 | if (ldata->column > 0) |
704 | ldata->column--; | |
a88a69c9 JP |
705 | } |
706 | cp += 3; | |
707 | nr -= 3; | |
708 | break; | |
709 | ||
710 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 711 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
712 | cp += 2; |
713 | nr -= 2; | |
714 | break; | |
715 | ||
716 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
717 | if (ldata->column > 0) |
718 | ldata->column--; | |
a88a69c9 JP |
719 | cp += 2; |
720 | nr -= 2; | |
721 | break; | |
722 | ||
723 | case ECHO_OP_START: | |
724 | /* This is an escaped echo op start code */ | |
725 | if (!space) { | |
726 | no_space_left = 1; | |
727 | break; | |
728 | } | |
729 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 730 | ldata->column++; |
a88a69c9 JP |
731 | space--; |
732 | cp += 2; | |
733 | nr -= 2; | |
734 | break; | |
735 | ||
736 | default: | |
a88a69c9 | 737 | /* |
62b26358 JP |
738 | * If the op is not a special byte code, |
739 | * it is a ctrl char tagged to be echoed | |
740 | * as "^X" (where X is the letter | |
741 | * representing the control char). | |
742 | * Note that we must ensure there is | |
743 | * enough space for the whole ctrl pair. | |
744 | * | |
a88a69c9 | 745 | */ |
62b26358 JP |
746 | if (space < 2) { |
747 | no_space_left = 1; | |
748 | break; | |
749 | } | |
750 | tty_put_char(tty, '^'); | |
751 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 752 | ldata->column += 2; |
62b26358 | 753 | space -= 2; |
a88a69c9 JP |
754 | cp += 2; |
755 | nr -= 2; | |
756 | } | |
757 | ||
758 | if (no_space_left) | |
759 | break; | |
760 | } else { | |
582f5590 | 761 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
762 | int retval = do_output_char(c, tty, space); |
763 | if (retval < 0) | |
764 | break; | |
765 | space -= retval; | |
766 | } else { | |
767 | if (!space) | |
768 | break; | |
769 | tty_put_char(tty, c); | |
770 | space -= 1; | |
771 | } | |
a88a69c9 JP |
772 | cp += 1; |
773 | nr -= 1; | |
774 | } | |
775 | ||
776 | /* When end of circular buffer reached, wrap around */ | |
777 | if (cp >= buf_end) | |
778 | cp -= N_TTY_BUF_SIZE; | |
779 | } | |
780 | ||
781 | if (nr == 0) { | |
ba2e68ac JS |
782 | ldata->echo_pos = 0; |
783 | ldata->echo_cnt = 0; | |
a88a69c9 | 784 | } else { |
ba2e68ac JS |
785 | int num_processed = ldata->echo_cnt - nr; |
786 | ldata->echo_pos += num_processed; | |
787 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; | |
788 | ldata->echo_cnt = nr; | |
a88a69c9 JP |
789 | } |
790 | ||
bddc7152 JS |
791 | mutex_unlock(&ldata->echo_lock); |
792 | mutex_unlock(&ldata->output_lock); | |
a88a69c9 JP |
793 | |
794 | if (tty->ops->flush_chars) | |
795 | tty->ops->flush_chars(tty); | |
796 | } | |
797 | ||
798 | /** | |
799 | * add_echo_byte - add a byte to the echo buffer | |
800 | * @c: unicode byte to echo | |
57c94121 | 801 | * @ldata: n_tty data |
a88a69c9 JP |
802 | * |
803 | * Add a character or operation byte to the echo buffer. | |
804 | * | |
805 | * Should be called under the echo lock to protect the echo buffer. | |
806 | */ | |
807 | ||
57c94121 | 808 | static void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 JP |
809 | { |
810 | int new_byte_pos; | |
811 | ||
ba2e68ac | 812 | if (ldata->echo_cnt == N_TTY_BUF_SIZE) { |
a88a69c9 | 813 | /* Circular buffer is already at capacity */ |
ba2e68ac | 814 | new_byte_pos = ldata->echo_pos; |
a88a69c9 JP |
815 | |
816 | /* | |
817 | * Since the buffer start position needs to be advanced, | |
818 | * be sure to step by a whole operation byte group. | |
819 | */ | |
ba2e68ac JS |
820 | if (ldata->echo_buf[ldata->echo_pos] == ECHO_OP_START) { |
821 | if (ldata->echo_buf[(ldata->echo_pos + 1) & | |
a88a69c9 JP |
822 | (N_TTY_BUF_SIZE - 1)] == |
823 | ECHO_OP_ERASE_TAB) { | |
ba2e68ac JS |
824 | ldata->echo_pos += 3; |
825 | ldata->echo_cnt -= 2; | |
a88a69c9 | 826 | } else { |
ba2e68ac JS |
827 | ldata->echo_pos += 2; |
828 | ldata->echo_cnt -= 1; | |
a88a69c9 JP |
829 | } |
830 | } else { | |
ba2e68ac | 831 | ldata->echo_pos++; |
a88a69c9 | 832 | } |
ba2e68ac | 833 | ldata->echo_pos &= N_TTY_BUF_SIZE - 1; |
a88a69c9 | 834 | } else { |
ba2e68ac | 835 | new_byte_pos = ldata->echo_pos + ldata->echo_cnt; |
a88a69c9 | 836 | new_byte_pos &= N_TTY_BUF_SIZE - 1; |
ba2e68ac | 837 | ldata->echo_cnt++; |
a88a69c9 JP |
838 | } |
839 | ||
ba2e68ac | 840 | ldata->echo_buf[new_byte_pos] = c; |
a88a69c9 JP |
841 | } |
842 | ||
843 | /** | |
844 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 845 | * @ldata: n_tty data |
a88a69c9 JP |
846 | * |
847 | * Add an operation to the echo buffer to move back one column. | |
848 | * | |
849 | * Locking: echo_lock to protect the echo buffer | |
850 | */ | |
851 | ||
57c94121 | 852 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 853 | { |
bddc7152 | 854 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
855 | add_echo_byte(ECHO_OP_START, ldata); |
856 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
bddc7152 | 857 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
858 | } |
859 | ||
860 | /** | |
861 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 862 | * @ldata: n_tty data |
a88a69c9 JP |
863 | * |
864 | * Add an operation to the echo buffer to set the canon column | |
865 | * to the current column. | |
866 | * | |
867 | * Locking: echo_lock to protect the echo buffer | |
868 | */ | |
869 | ||
57c94121 | 870 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 871 | { |
bddc7152 | 872 | mutex_lock(&ldata->echo_lock); |
57c94121 JS |
873 | add_echo_byte(ECHO_OP_START, ldata); |
874 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
bddc7152 | 875 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
876 | } |
877 | ||
878 | /** | |
879 | * echo_erase_tab - add operation to erase a tab | |
880 | * @num_chars: number of character columns already used | |
881 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 882 | * @ldata: n_tty data |
a88a69c9 JP |
883 | * |
884 | * Add an operation to the echo buffer to erase a tab. | |
885 | * | |
886 | * Called by the eraser function, which knows how many character | |
887 | * columns have been used since either a previous tab or the start | |
888 | * of input. This information will be used later, along with | |
889 | * canon column (if applicable), to go back the correct number | |
890 | * of columns. | |
891 | * | |
892 | * Locking: echo_lock to protect the echo buffer | |
893 | */ | |
894 | ||
895 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 896 | struct n_tty_data *ldata) |
a88a69c9 | 897 | { |
bddc7152 | 898 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 899 | |
57c94121 JS |
900 | add_echo_byte(ECHO_OP_START, ldata); |
901 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
902 | |
903 | /* We only need to know this modulo 8 (tab spacing) */ | |
904 | num_chars &= 7; | |
905 | ||
906 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
907 | if (after_tab) | |
908 | num_chars |= 0x80; | |
300a6204 | 909 | |
57c94121 | 910 | add_echo_byte(num_chars, ldata); |
a88a69c9 | 911 | |
bddc7152 | 912 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 JP |
913 | } |
914 | ||
915 | /** | |
916 | * echo_char_raw - echo a character raw | |
917 | * @c: unicode byte to echo | |
918 | * @tty: terminal device | |
919 | * | |
920 | * Echo user input back onto the screen. This must be called only when | |
921 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
922 | * | |
923 | * This variant does not treat control characters specially. | |
924 | * | |
925 | * Locking: echo_lock to protect the echo buffer | |
926 | */ | |
927 | ||
57c94121 | 928 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 929 | { |
bddc7152 | 930 | mutex_lock(&ldata->echo_lock); |
a88a69c9 | 931 | if (c == ECHO_OP_START) { |
57c94121 JS |
932 | add_echo_byte(ECHO_OP_START, ldata); |
933 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 934 | } else { |
57c94121 | 935 | add_echo_byte(c, ldata); |
a88a69c9 | 936 | } |
bddc7152 | 937 | mutex_unlock(&ldata->echo_lock); |
a88a69c9 | 938 | } |
1da177e4 | 939 | |
1da177e4 | 940 | /** |
a88a69c9 | 941 | * echo_char - echo a character |
1da177e4 LT |
942 | * @c: unicode byte to echo |
943 | * @tty: terminal device | |
944 | * | |
4edf1827 | 945 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 946 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 947 | * |
62b26358 JP |
948 | * This variant tags control characters to be echoed as "^X" |
949 | * (where X is the letter representing the control char). | |
a88a69c9 JP |
950 | * |
951 | * Locking: echo_lock to protect the echo buffer | |
1da177e4 LT |
952 | */ |
953 | ||
954 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
955 | { | |
bddc7152 JS |
956 | struct n_tty_data *ldata = tty->disc_data; |
957 | ||
958 | mutex_lock(&ldata->echo_lock); | |
a88a69c9 JP |
959 | |
960 | if (c == ECHO_OP_START) { | |
57c94121 JS |
961 | add_echo_byte(ECHO_OP_START, ldata); |
962 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 963 | } else { |
62b26358 | 964 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
965 | add_echo_byte(ECHO_OP_START, ldata); |
966 | add_echo_byte(c, ldata); | |
a88a69c9 JP |
967 | } |
968 | ||
bddc7152 | 969 | mutex_unlock(&ldata->echo_lock); |
1da177e4 LT |
970 | } |
971 | ||
17b82060 | 972 | /** |
a88a69c9 | 973 | * finish_erasing - complete erase |
57c94121 | 974 | * @ldata: n_tty data |
17b82060 | 975 | */ |
a88a69c9 | 976 | |
57c94121 | 977 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 978 | { |
53c5ee2c | 979 | if (ldata->erasing) { |
57c94121 | 980 | echo_char_raw('/', ldata); |
53c5ee2c | 981 | ldata->erasing = 0; |
1da177e4 LT |
982 | } |
983 | } | |
984 | ||
985 | /** | |
986 | * eraser - handle erase function | |
987 | * @c: character input | |
988 | * @tty: terminal device | |
989 | * | |
3a4fa0a2 | 990 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
991 | * present in the stream from the driver layer. Handles the complexities |
992 | * of UTF-8 multibyte symbols. | |
17b82060 | 993 | * |
6d76bd26 PH |
994 | * n_tty_receive_buf()/producer path: |
995 | * caller holds non-exclusive termios_rwsem | |
996 | * modifies read_head | |
997 | * | |
998 | * Modifying the read_head is not considered a publish in this context | |
999 | * because canonical mode is active -- only canon_head publishes | |
1da177e4 | 1000 | */ |
4edf1827 | 1001 | |
1da177e4 LT |
1002 | static void eraser(unsigned char c, struct tty_struct *tty) |
1003 | { | |
53c5ee2c | 1004 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1005 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
1006 | size_t head; |
1007 | size_t cnt; | |
1008 | int seen_alnums; | |
1da177e4 | 1009 | |
ba2e68ac | 1010 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 1011 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
1012 | return; |
1013 | } | |
1014 | if (c == ERASE_CHAR(tty)) | |
1015 | kill_type = ERASE; | |
1016 | else if (c == WERASE_CHAR(tty)) | |
1017 | kill_type = WERASE; | |
1018 | else { | |
1019 | if (!L_ECHO(tty)) { | |
ba2e68ac | 1020 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
1021 | return; |
1022 | } | |
1023 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 1024 | ldata->read_head = ldata->canon_head; |
57c94121 | 1025 | finish_erasing(ldata); |
1da177e4 LT |
1026 | echo_char(KILL_CHAR(tty), tty); |
1027 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
1028 | if (L_ECHOK(tty)) | |
57c94121 | 1029 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1030 | return; |
1031 | } | |
1032 | kill_type = KILL; | |
1033 | } | |
1034 | ||
1035 | seen_alnums = 0; | |
ba2e68ac JS |
1036 | while (ldata->read_head != ldata->canon_head) { |
1037 | head = ldata->read_head; | |
1da177e4 LT |
1038 | |
1039 | /* erase a single possibly multibyte character */ | |
1040 | do { | |
bc5a5e3f PH |
1041 | head--; |
1042 | c = read_buf(ldata, head); | |
ba2e68ac | 1043 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1044 | |
1045 | /* do not partially erase */ | |
1046 | if (is_continuation(c, tty)) | |
1047 | break; | |
1048 | ||
1049 | if (kill_type == WERASE) { | |
1050 | /* Equivalent to BSD's ALTWERASE. */ | |
1051 | if (isalnum(c) || c == '_') | |
1052 | seen_alnums++; | |
1053 | else if (seen_alnums) | |
1054 | break; | |
1055 | } | |
bc5a5e3f | 1056 | cnt = ldata->read_head - head; |
ba2e68ac | 1057 | ldata->read_head = head; |
1da177e4 LT |
1058 | if (L_ECHO(tty)) { |
1059 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1060 | if (!ldata->erasing) { |
57c94121 | 1061 | echo_char_raw('\\', ldata); |
53c5ee2c | 1062 | ldata->erasing = 1; |
1da177e4 LT |
1063 | } |
1064 | /* if cnt > 1, output a multi-byte character */ | |
1065 | echo_char(c, tty); | |
1066 | while (--cnt > 0) { | |
bc5a5e3f PH |
1067 | head++; |
1068 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1069 | echo_move_back_col(ldata); |
1da177e4 LT |
1070 | } |
1071 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1072 | echo_char(ERASE_CHAR(tty), tty); | |
1073 | } else if (c == '\t') { | |
a88a69c9 JP |
1074 | unsigned int num_chars = 0; |
1075 | int after_tab = 0; | |
bc5a5e3f | 1076 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1077 | |
1078 | /* | |
1079 | * Count the columns used for characters | |
1080 | * since the start of input or after a | |
1081 | * previous tab. | |
1082 | * This info is used to go back the correct | |
1083 | * number of columns. | |
1084 | */ | |
ba2e68ac | 1085 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1086 | tail--; |
1087 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1088 | if (c == '\t') { |
1089 | after_tab = 1; | |
1090 | break; | |
300a6204 | 1091 | } else if (iscntrl(c)) { |
1da177e4 | 1092 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1093 | num_chars += 2; |
1094 | } else if (!is_continuation(c, tty)) { | |
1095 | num_chars++; | |
1096 | } | |
1da177e4 | 1097 | } |
57c94121 | 1098 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1099 | } else { |
1100 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1101 | echo_char_raw('\b', ldata); |
1102 | echo_char_raw(' ', ldata); | |
1103 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1104 | } |
1105 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1106 | echo_char_raw('\b', ldata); |
1107 | echo_char_raw(' ', ldata); | |
1108 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1109 | } |
1110 | } | |
1111 | } | |
1112 | if (kill_type == ERASE) | |
1113 | break; | |
1114 | } | |
ba2e68ac | 1115 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1116 | finish_erasing(ldata); |
1da177e4 LT |
1117 | } |
1118 | ||
1119 | /** | |
1120 | * isig - handle the ISIG optio | |
1121 | * @sig: signal | |
1122 | * @tty: terminal | |
1da177e4 | 1123 | * |
8c985d18 PH |
1124 | * Called when a signal is being sent due to terminal input. |
1125 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1126 | * |
8c985d18 | 1127 | * Locking: ctrl_lock |
1da177e4 | 1128 | */ |
4edf1827 | 1129 | |
8c985d18 | 1130 | static inline void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1131 | { |
8c985d18 PH |
1132 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1133 | if (tty_pgrp) { | |
1134 | kill_pgrp(tty_pgrp, sig, 1); | |
1135 | put_pid(tty_pgrp); | |
1da177e4 LT |
1136 | } |
1137 | } | |
1138 | ||
1139 | /** | |
1140 | * n_tty_receive_break - handle break | |
1141 | * @tty: terminal | |
1142 | * | |
1143 | * An RS232 break event has been hit in the incoming bitstream. This | |
1144 | * can cause a variety of events depending upon the termios settings. | |
1145 | * | |
6d76bd26 PH |
1146 | * n_tty_receive_buf()/producer path: |
1147 | * caller holds non-exclusive termios_rwsem | |
1148 | * publishes read_head via put_tty_queue() | |
1149 | * | |
1150 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1151 | */ |
4edf1827 | 1152 | |
1da177e4 LT |
1153 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1154 | { | |
57c94121 JS |
1155 | struct n_tty_data *ldata = tty->disc_data; |
1156 | ||
1da177e4 LT |
1157 | if (I_IGNBRK(tty)) |
1158 | return; | |
1159 | if (I_BRKINT(tty)) { | |
8c985d18 PH |
1160 | isig(SIGINT, tty); |
1161 | if (!L_NOFLSH(tty)) { | |
6d76bd26 PH |
1162 | /* flushing needs exclusive termios_rwsem */ |
1163 | up_read(&tty->termios_rwsem); | |
8c985d18 PH |
1164 | n_tty_flush_buffer(tty); |
1165 | tty_driver_flush_buffer(tty); | |
6d76bd26 | 1166 | down_read(&tty->termios_rwsem); |
8c985d18 | 1167 | } |
1da177e4 LT |
1168 | return; |
1169 | } | |
1170 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1171 | put_tty_queue('\377', ldata); |
1172 | put_tty_queue('\0', ldata); | |
1da177e4 | 1173 | } |
57c94121 | 1174 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1175 | wake_up_interruptible(&tty->read_wait); |
1176 | } | |
1177 | ||
1178 | /** | |
1179 | * n_tty_receive_overrun - handle overrun reporting | |
1180 | * @tty: terminal | |
1181 | * | |
1182 | * Data arrived faster than we could process it. While the tty | |
1183 | * driver has flagged this the bits that were missed are gone | |
1184 | * forever. | |
1185 | * | |
1186 | * Called from the receive_buf path so single threaded. Does not | |
1187 | * need locking as num_overrun and overrun_time are function | |
1188 | * private. | |
1189 | */ | |
4edf1827 | 1190 | |
1da177e4 LT |
1191 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1192 | { | |
53c5ee2c | 1193 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1194 | char buf[64]; |
1195 | ||
53c5ee2c JS |
1196 | ldata->num_overrun++; |
1197 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1198 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1199 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1200 | tty_name(tty, buf), | |
53c5ee2c JS |
1201 | ldata->num_overrun); |
1202 | ldata->overrun_time = jiffies; | |
1203 | ldata->num_overrun = 0; | |
1da177e4 LT |
1204 | } |
1205 | } | |
1206 | ||
1207 | /** | |
1208 | * n_tty_receive_parity_error - error notifier | |
1209 | * @tty: terminal device | |
1210 | * @c: character | |
1211 | * | |
1212 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1213 | * the error case if necessary. |
1214 | * | |
1215 | * n_tty_receive_buf()/producer path: | |
1216 | * caller holds non-exclusive termios_rwsem | |
1217 | * publishes read_head via put_tty_queue() | |
1da177e4 LT |
1218 | */ |
1219 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1220 | unsigned char c) | |
1221 | { | |
57c94121 JS |
1222 | struct n_tty_data *ldata = tty->disc_data; |
1223 | ||
4edf1827 | 1224 | if (I_IGNPAR(tty)) |
1da177e4 | 1225 | return; |
1da177e4 | 1226 | if (I_PARMRK(tty)) { |
57c94121 JS |
1227 | put_tty_queue('\377', ldata); |
1228 | put_tty_queue('\0', ldata); | |
1229 | put_tty_queue(c, ldata); | |
1da177e4 | 1230 | } else if (I_INPCK(tty)) |
57c94121 | 1231 | put_tty_queue('\0', ldata); |
1da177e4 | 1232 | else |
57c94121 | 1233 | put_tty_queue(c, ldata); |
1da177e4 LT |
1234 | wake_up_interruptible(&tty->read_wait); |
1235 | } | |
1236 | ||
1237 | /** | |
1238 | * n_tty_receive_char - perform processing | |
1239 | * @tty: terminal device | |
1240 | * @c: character | |
1241 | * | |
1242 | * Process an individual character of input received from the driver. | |
4edf1827 | 1243 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1244 | * driver above. |
6d76bd26 PH |
1245 | * |
1246 | * n_tty_receive_buf()/producer path: | |
1247 | * caller holds non-exclusive termios_rwsem | |
1248 | * publishes canon_head if canonical mode is active | |
1249 | * otherwise, publishes read_head via put_tty_queue() | |
1da177e4 LT |
1250 | */ |
1251 | ||
1252 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1253 | { | |
53c5ee2c | 1254 | struct n_tty_data *ldata = tty->disc_data; |
acc71bba | 1255 | int parmrk; |
1da177e4 | 1256 | |
53c5ee2c | 1257 | if (ldata->raw) { |
57c94121 | 1258 | put_tty_queue(c, ldata); |
1da177e4 LT |
1259 | return; |
1260 | } | |
4edf1827 | 1261 | |
1da177e4 LT |
1262 | if (I_ISTRIP(tty)) |
1263 | c &= 0x7f; | |
1264 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1265 | c = tolower(c); |
1da177e4 | 1266 | |
26df6d13 | 1267 | if (L_EXTPROC(tty)) { |
57c94121 | 1268 | put_tty_queue(c, ldata); |
26df6d13 | 1269 | return; |
1270 | } | |
1271 | ||
54d2a37e | 1272 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1273 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1274 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1275 | start_tty(tty); |
a88a69c9 JP |
1276 | process_echoes(tty); |
1277 | } | |
54d2a37e | 1278 | |
1da177e4 LT |
1279 | if (tty->closing) { |
1280 | if (I_IXON(tty)) { | |
a88a69c9 | 1281 | if (c == START_CHAR(tty)) { |
1da177e4 | 1282 | start_tty(tty); |
a88a69c9 | 1283 | process_echoes(tty); |
300a6204 | 1284 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1285 | stop_tty(tty); |
1286 | } | |
1287 | return; | |
1288 | } | |
1289 | ||
1290 | /* | |
1291 | * If the previous character was LNEXT, or we know that this | |
1292 | * character is not one of the characters that we'll have to | |
1293 | * handle specially, do shortcut processing to speed things | |
1294 | * up. | |
1295 | */ | |
3fe780b3 | 1296 | if (!test_bit(c, ldata->process_char_map) || ldata->lnext) { |
53c5ee2c | 1297 | ldata->lnext = 0; |
acc71bba | 1298 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ce74117a | 1299 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1300 | /* beep if no space */ |
7e94b1d9 JP |
1301 | if (L_ECHO(tty)) |
1302 | process_output('\a', tty); | |
acc71bba JP |
1303 | return; |
1304 | } | |
1305 | if (L_ECHO(tty)) { | |
57c94121 | 1306 | finish_erasing(ldata); |
1da177e4 | 1307 | /* Record the column of first canon char. */ |
ba2e68ac | 1308 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1309 | echo_set_canon_col(ldata); |
1da177e4 | 1310 | echo_char(c, tty); |
a88a69c9 | 1311 | process_echoes(tty); |
1da177e4 | 1312 | } |
acc71bba | 1313 | if (parmrk) |
57c94121 JS |
1314 | put_tty_queue(c, ldata); |
1315 | put_tty_queue(c, ldata); | |
1da177e4 LT |
1316 | return; |
1317 | } | |
4edf1827 | 1318 | |
1da177e4 LT |
1319 | if (I_IXON(tty)) { |
1320 | if (c == START_CHAR(tty)) { | |
1321 | start_tty(tty); | |
a88a69c9 | 1322 | process_echoes(tty); |
1da177e4 LT |
1323 | return; |
1324 | } | |
1325 | if (c == STOP_CHAR(tty)) { | |
1326 | stop_tty(tty); | |
1327 | return; | |
1328 | } | |
1329 | } | |
575537b3 | 1330 | |
1da177e4 LT |
1331 | if (L_ISIG(tty)) { |
1332 | int signal; | |
1333 | signal = SIGINT; | |
1334 | if (c == INTR_CHAR(tty)) | |
1335 | goto send_signal; | |
1336 | signal = SIGQUIT; | |
1337 | if (c == QUIT_CHAR(tty)) | |
1338 | goto send_signal; | |
1339 | signal = SIGTSTP; | |
1340 | if (c == SUSP_CHAR(tty)) { | |
1341 | send_signal: | |
ec5b1157 | 1342 | if (!L_NOFLSH(tty)) { |
6d76bd26 PH |
1343 | /* flushing needs exclusive termios_rwsem */ |
1344 | up_read(&tty->termios_rwsem); | |
ec5b1157 | 1345 | n_tty_flush_buffer(tty); |
f34d7a5b | 1346 | tty_driver_flush_buffer(tty); |
6d76bd26 | 1347 | down_read(&tty->termios_rwsem); |
ec5b1157 | 1348 | } |
a88a69c9 JP |
1349 | if (I_IXON(tty)) |
1350 | start_tty(tty); | |
1351 | if (L_ECHO(tty)) { | |
ec5b1157 | 1352 | echo_char(c, tty); |
a88a69c9 JP |
1353 | process_echoes(tty); |
1354 | } | |
8c985d18 | 1355 | isig(signal, tty); |
1da177e4 LT |
1356 | return; |
1357 | } | |
1358 | } | |
575537b3 JP |
1359 | |
1360 | if (c == '\r') { | |
1361 | if (I_IGNCR(tty)) | |
1362 | return; | |
1363 | if (I_ICRNL(tty)) | |
1364 | c = '\n'; | |
1365 | } else if (c == '\n' && I_INLCR(tty)) | |
1366 | c = '\r'; | |
1367 | ||
53c5ee2c | 1368 | if (ldata->icanon) { |
1da177e4 LT |
1369 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1370 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1371 | eraser(c, tty); | |
a88a69c9 | 1372 | process_echoes(tty); |
1da177e4 LT |
1373 | return; |
1374 | } | |
1375 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1376 | ldata->lnext = 1; |
1da177e4 | 1377 | if (L_ECHO(tty)) { |
57c94121 | 1378 | finish_erasing(ldata); |
1da177e4 | 1379 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1380 | echo_char_raw('^', ldata); |
1381 | echo_char_raw('\b', ldata); | |
a88a69c9 | 1382 | process_echoes(tty); |
1da177e4 LT |
1383 | } |
1384 | } | |
1385 | return; | |
1386 | } | |
1387 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1388 | L_IEXTEN(tty)) { | |
bc5a5e3f | 1389 | size_t tail = ldata->canon_head; |
1da177e4 | 1390 | |
57c94121 | 1391 | finish_erasing(ldata); |
1da177e4 | 1392 | echo_char(c, tty); |
57c94121 | 1393 | echo_char_raw('\n', ldata); |
ba2e68ac | 1394 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1395 | echo_char(read_buf(ldata, tail), tty); |
1396 | tail++; | |
1da177e4 | 1397 | } |
a88a69c9 | 1398 | process_echoes(tty); |
1da177e4 LT |
1399 | return; |
1400 | } | |
1401 | if (c == '\n') { | |
ce74117a | 1402 | if (read_cnt(ldata) >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1403 | if (L_ECHO(tty)) |
1404 | process_output('\a', tty); | |
acc71bba JP |
1405 | return; |
1406 | } | |
1407 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
57c94121 | 1408 | echo_char_raw('\n', ldata); |
a88a69c9 | 1409 | process_echoes(tty); |
1da177e4 LT |
1410 | } |
1411 | goto handle_newline; | |
1412 | } | |
1413 | if (c == EOF_CHAR(tty)) { | |
ce74117a | 1414 | if (read_cnt(ldata) >= N_TTY_BUF_SIZE) |
acc71bba | 1415 | return; |
ba2e68ac | 1416 | if (ldata->canon_head != ldata->read_head) |
4edf1827 | 1417 | set_bit(TTY_PUSH, &tty->flags); |
1da177e4 LT |
1418 | c = __DISABLED_CHAR; |
1419 | goto handle_newline; | |
1420 | } | |
1421 | if ((c == EOL_CHAR(tty)) || | |
1422 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1423 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1424 | ? 1 : 0; | |
ce74117a | 1425 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk)) { |
7e94b1d9 JP |
1426 | if (L_ECHO(tty)) |
1427 | process_output('\a', tty); | |
acc71bba JP |
1428 | return; |
1429 | } | |
1da177e4 LT |
1430 | /* |
1431 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1432 | */ | |
1433 | if (L_ECHO(tty)) { | |
1da177e4 | 1434 | /* Record the column of first canon char. */ |
ba2e68ac | 1435 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1436 | echo_set_canon_col(ldata); |
1da177e4 | 1437 | echo_char(c, tty); |
a88a69c9 | 1438 | process_echoes(tty); |
1da177e4 LT |
1439 | } |
1440 | /* | |
1441 | * XXX does PARMRK doubling happen for | |
1442 | * EOL_CHAR and EOL2_CHAR? | |
1443 | */ | |
acc71bba | 1444 | if (parmrk) |
57c94121 | 1445 | put_tty_queue(c, ldata); |
1da177e4 | 1446 | |
4edf1827 | 1447 | handle_newline: |
bc5a5e3f | 1448 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1449 | put_tty_queue(c, ldata); |
ba2e68ac | 1450 | ldata->canon_head = ldata->read_head; |
1da177e4 LT |
1451 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1452 | if (waitqueue_active(&tty->read_wait)) | |
1453 | wake_up_interruptible(&tty->read_wait); | |
1454 | return; | |
1455 | } | |
1456 | } | |
4edf1827 | 1457 | |
acc71bba | 1458 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ce74117a | 1459 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1460 | /* beep if no space */ |
7e94b1d9 JP |
1461 | if (L_ECHO(tty)) |
1462 | process_output('\a', tty); | |
acc71bba JP |
1463 | return; |
1464 | } | |
1465 | if (L_ECHO(tty)) { | |
57c94121 | 1466 | finish_erasing(ldata); |
1da177e4 | 1467 | if (c == '\n') |
57c94121 | 1468 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1469 | else { |
1470 | /* Record the column of first canon char. */ | |
ba2e68ac | 1471 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1472 | echo_set_canon_col(ldata); |
1da177e4 LT |
1473 | echo_char(c, tty); |
1474 | } | |
a88a69c9 | 1475 | process_echoes(tty); |
1da177e4 LT |
1476 | } |
1477 | ||
acc71bba | 1478 | if (parmrk) |
57c94121 | 1479 | put_tty_queue(c, ldata); |
1da177e4 | 1480 | |
57c94121 | 1481 | put_tty_queue(c, ldata); |
4edf1827 | 1482 | } |
1da177e4 | 1483 | |
1da177e4 LT |
1484 | /** |
1485 | * n_tty_receive_buf - data receive | |
1486 | * @tty: terminal device | |
1487 | * @cp: buffer | |
1488 | * @fp: flag buffer | |
1489 | * @count: characters | |
1490 | * | |
1491 | * Called by the terminal driver when a block of characters has | |
1492 | * been received. This function must be called from soft contexts | |
1493 | * not from interrupt context. The driver is responsible for making | |
1494 | * calls one at a time and in order (or using flush_to_ldisc) | |
6d76bd26 PH |
1495 | * |
1496 | * n_tty_receive_buf()/producer path: | |
1497 | * claims non-exclusive termios_rwsem | |
1498 | * publishes read_head and canon_head | |
1da177e4 | 1499 | */ |
4edf1827 | 1500 | |
24a89d1c PH |
1501 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1502 | char *fp, int count) | |
1da177e4 | 1503 | { |
53c5ee2c | 1504 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1505 | const unsigned char *p; |
1506 | char *f, flags = TTY_NORMAL; | |
1da177e4 | 1507 | char buf[64]; |
1da177e4 | 1508 | |
53c5ee2c | 1509 | if (ldata->real_raw) { |
d1913e39 PH |
1510 | size_t n, head; |
1511 | ||
1512 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1513 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1514 | n = min_t(size_t, count, n); | |
1515 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1516 | ldata->read_head += n; | |
1517 | cp += n; | |
1518 | count -= n; | |
1519 | ||
1520 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1521 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1522 | n = min_t(size_t, count, n); | |
1523 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1524 | ldata->read_head += n; | |
1da177e4 | 1525 | } else { |
d1913e39 PH |
1526 | int i; |
1527 | ||
4edf1827 | 1528 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1529 | if (f) |
1530 | flags = *f++; | |
1531 | switch (flags) { | |
1532 | case TTY_NORMAL: | |
1533 | n_tty_receive_char(tty, *p); | |
1534 | break; | |
1535 | case TTY_BREAK: | |
1536 | n_tty_receive_break(tty); | |
1537 | break; | |
1538 | case TTY_PARITY: | |
1539 | case TTY_FRAME: | |
1540 | n_tty_receive_parity_error(tty, *p); | |
1541 | break; | |
1542 | case TTY_OVERRUN: | |
1543 | n_tty_receive_overrun(tty); | |
1544 | break; | |
1545 | default: | |
4edf1827 | 1546 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1547 | tty_name(tty, buf), flags); |
1548 | break; | |
1549 | } | |
1550 | } | |
f34d7a5b AC |
1551 | if (tty->ops->flush_chars) |
1552 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1553 | } |
1554 | ||
ce74117a | 1555 | if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) || |
26df6d13 | 1556 | L_EXTPROC(tty)) { |
1da177e4 LT |
1557 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1558 | if (waitqueue_active(&tty->read_wait)) | |
1559 | wake_up_interruptible(&tty->read_wait); | |
1560 | } | |
1561 | ||
6367ca72 | 1562 | n_tty_check_throttle(tty); |
1da177e4 LT |
1563 | } |
1564 | ||
24a89d1c PH |
1565 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1566 | char *fp, int count) | |
1567 | { | |
9356b535 | 1568 | down_read(&tty->termios_rwsem); |
24a89d1c | 1569 | __receive_buf(tty, cp, fp, count); |
9356b535 | 1570 | up_read(&tty->termios_rwsem); |
24a89d1c PH |
1571 | } |
1572 | ||
1573 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1574 | char *fp, int count) | |
1575 | { | |
1576 | struct n_tty_data *ldata = tty->disc_data; | |
1577 | int room; | |
1578 | ||
9356b535 PH |
1579 | down_read(&tty->termios_rwsem); |
1580 | ||
24a89d1c PH |
1581 | tty->receive_room = room = receive_room(tty); |
1582 | if (!room) | |
1583 | ldata->no_room = 1; | |
1584 | count = min(count, room); | |
1585 | if (count) | |
1586 | __receive_buf(tty, cp, fp, count); | |
1587 | ||
9356b535 PH |
1588 | up_read(&tty->termios_rwsem); |
1589 | ||
24a89d1c PH |
1590 | return count; |
1591 | } | |
1592 | ||
1da177e4 LT |
1593 | int is_ignored(int sig) |
1594 | { | |
1595 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1596 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1597 | } |
1598 | ||
1599 | /** | |
1600 | * n_tty_set_termios - termios data changed | |
1601 | * @tty: terminal | |
1602 | * @old: previous data | |
1603 | * | |
1604 | * Called by the tty layer when the user changes termios flags so | |
1605 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1606 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1607 | * guaranteed that this function will not be re-entered or in progress |
1608 | * when the ldisc is closed. | |
17b82060 | 1609 | * |
6a1c0680 | 1610 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1611 | */ |
4edf1827 AC |
1612 | |
1613 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1614 | { |
53c5ee2c | 1615 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1616 | int canon_change = 1; |
47afa7a5 AC |
1617 | |
1618 | if (old) | |
adc8d746 | 1619 | canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON; |
47afa7a5 | 1620 | if (canon_change) { |
3fe780b3 | 1621 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
ba2e68ac | 1622 | ldata->canon_head = ldata->read_tail; |
53c5ee2c | 1623 | ldata->erasing = 0; |
6f9b028a | 1624 | ldata->lnext = 0; |
47afa7a5 AC |
1625 | } |
1626 | ||
ce74117a | 1627 | if (canon_change && !L_ICANON(tty) && read_cnt(ldata)) |
47afa7a5 | 1628 | wake_up_interruptible(&tty->read_wait); |
4edf1827 | 1629 | |
53c5ee2c | 1630 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1631 | |
1da177e4 LT |
1632 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1633 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1634 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1635 | I_PARMRK(tty)) { | |
3fe780b3 | 1636 | bitmap_zero(ldata->process_char_map, 256); |
1da177e4 LT |
1637 | |
1638 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
3fe780b3 | 1639 | set_bit('\r', ldata->process_char_map); |
1da177e4 | 1640 | if (I_INLCR(tty)) |
3fe780b3 | 1641 | set_bit('\n', ldata->process_char_map); |
1da177e4 LT |
1642 | |
1643 | if (L_ICANON(tty)) { | |
3fe780b3 JS |
1644 | set_bit(ERASE_CHAR(tty), ldata->process_char_map); |
1645 | set_bit(KILL_CHAR(tty), ldata->process_char_map); | |
1646 | set_bit(EOF_CHAR(tty), ldata->process_char_map); | |
1647 | set_bit('\n', ldata->process_char_map); | |
1648 | set_bit(EOL_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1649 | if (L_IEXTEN(tty)) { |
1650 | set_bit(WERASE_CHAR(tty), | |
3fe780b3 | 1651 | ldata->process_char_map); |
1da177e4 | 1652 | set_bit(LNEXT_CHAR(tty), |
3fe780b3 | 1653 | ldata->process_char_map); |
1da177e4 | 1654 | set_bit(EOL2_CHAR(tty), |
3fe780b3 | 1655 | ldata->process_char_map); |
1da177e4 LT |
1656 | if (L_ECHO(tty)) |
1657 | set_bit(REPRINT_CHAR(tty), | |
3fe780b3 | 1658 | ldata->process_char_map); |
1da177e4 LT |
1659 | } |
1660 | } | |
1661 | if (I_IXON(tty)) { | |
3fe780b3 JS |
1662 | set_bit(START_CHAR(tty), ldata->process_char_map); |
1663 | set_bit(STOP_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1664 | } |
1665 | if (L_ISIG(tty)) { | |
3fe780b3 JS |
1666 | set_bit(INTR_CHAR(tty), ldata->process_char_map); |
1667 | set_bit(QUIT_CHAR(tty), ldata->process_char_map); | |
1668 | set_bit(SUSP_CHAR(tty), ldata->process_char_map); | |
1da177e4 | 1669 | } |
3fe780b3 | 1670 | clear_bit(__DISABLED_CHAR, ldata->process_char_map); |
53c5ee2c JS |
1671 | ldata->raw = 0; |
1672 | ldata->real_raw = 0; | |
1da177e4 | 1673 | } else { |
53c5ee2c | 1674 | ldata->raw = 1; |
1da177e4 LT |
1675 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1676 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1677 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1678 | ldata->real_raw = 1; |
1da177e4 | 1679 | else |
53c5ee2c | 1680 | ldata->real_raw = 0; |
1da177e4 | 1681 | } |
55db4c64 | 1682 | n_tty_set_room(tty); |
dab73b4e WY |
1683 | /* |
1684 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1685 | * been stopped by STOP_CHAR(tty) before it. | |
1686 | */ | |
1687 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { | |
1688 | start_tty(tty); | |
1689 | } | |
1690 | ||
f34d7a5b AC |
1691 | /* The termios change make the tty ready for I/O */ |
1692 | wake_up_interruptible(&tty->write_wait); | |
1693 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1694 | } |
1695 | ||
1696 | /** | |
1697 | * n_tty_close - close the ldisc for this tty | |
1698 | * @tty: device | |
1699 | * | |
4edf1827 AC |
1700 | * Called from the terminal layer when this line discipline is |
1701 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1702 | * discipline change. The function will not be called while other |
1703 | * ldisc methods are in progress. | |
1704 | */ | |
4edf1827 | 1705 | |
1da177e4 LT |
1706 | static void n_tty_close(struct tty_struct *tty) |
1707 | { | |
70ece7a7 JS |
1708 | struct n_tty_data *ldata = tty->disc_data; |
1709 | ||
79901317 PH |
1710 | if (tty->link) |
1711 | n_tty_packet_mode_flush(tty); | |
1712 | ||
ba2e68ac JS |
1713 | kfree(ldata->read_buf); |
1714 | kfree(ldata->echo_buf); | |
70ece7a7 | 1715 | kfree(ldata); |
70ece7a7 | 1716 | tty->disc_data = NULL; |
1da177e4 LT |
1717 | } |
1718 | ||
1719 | /** | |
1720 | * n_tty_open - open an ldisc | |
1721 | * @tty: terminal to open | |
1722 | * | |
4edf1827 | 1723 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1724 | * terminal device. Can sleep. Called serialized so that no |
1725 | * other events will occur in parallel. No further open will occur | |
1726 | * until a close. | |
1727 | */ | |
1728 | ||
1729 | static int n_tty_open(struct tty_struct *tty) | |
1730 | { | |
70ece7a7 JS |
1731 | struct n_tty_data *ldata; |
1732 | ||
1733 | ldata = kzalloc(sizeof(*ldata), GFP_KERNEL); | |
1734 | if (!ldata) | |
1735 | goto err; | |
1736 | ||
53c5ee2c | 1737 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1738 | mutex_init(&ldata->atomic_read_lock); |
1739 | mutex_init(&ldata->output_lock); | |
1740 | mutex_init(&ldata->echo_lock); | |
53c5ee2c | 1741 | |
a88a69c9 | 1742 | /* These are ugly. Currently a malloc failure here can panic */ |
ba2e68ac JS |
1743 | ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1744 | ldata->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); | |
1745 | if (!ldata->read_buf || !ldata->echo_buf) | |
b91939f5 | 1746 | goto err_free_bufs; |
0b4068a1 | 1747 | |
70ece7a7 | 1748 | tty->disc_data = ldata; |
b66f4fa5 | 1749 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1750 | ldata->column = 0; |
f6c8dbe6 | 1751 | ldata->minimum_to_wake = 1; |
1da177e4 | 1752 | tty->closing = 0; |
b66f4fa5 PH |
1753 | /* indicate buffer work may resume */ |
1754 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1755 | n_tty_set_termios(tty, NULL); | |
1756 | tty_unthrottle(tty); | |
70ece7a7 | 1757 | |
1da177e4 | 1758 | return 0; |
b91939f5 | 1759 | err_free_bufs: |
ba2e68ac JS |
1760 | kfree(ldata->read_buf); |
1761 | kfree(ldata->echo_buf); | |
70ece7a7 JS |
1762 | kfree(ldata); |
1763 | err: | |
b91939f5 | 1764 | return -ENOMEM; |
1da177e4 LT |
1765 | } |
1766 | ||
1767 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1768 | { | |
53c5ee2c JS |
1769 | struct n_tty_data *ldata = tty->disc_data; |
1770 | ||
53c5ee2c | 1771 | if (ldata->icanon && !L_EXTPROC(tty)) { |
a73d3d69 | 1772 | if (ldata->canon_head != ldata->read_tail) |
1da177e4 | 1773 | return 1; |
ce74117a | 1774 | } else if (read_cnt(ldata) >= (amt ? amt : 1)) |
1da177e4 LT |
1775 | return 1; |
1776 | ||
1777 | return 0; | |
1778 | } | |
1779 | ||
1780 | /** | |
bbd20759 | 1781 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1782 | * @tty: terminal device |
1783 | * @b: user data | |
1784 | * @nr: size of data | |
1785 | * | |
11a96d18 | 1786 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1787 | * ICANON is off; it copies characters straight from the tty queue to |
1788 | * user space directly. It can be profitably called twice; once to | |
1789 | * drain the space from the tail pointer to the (physical) end of the | |
1790 | * buffer, and once to drain the space from the (physical) beginning of | |
1791 | * the buffer to head pointer. | |
1792 | * | |
bddc7152 | 1793 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1794 | * |
6d76bd26 PH |
1795 | * n_tty_read()/consumer path: |
1796 | * caller holds non-exclusive termios_rwsem | |
1797 | * read_tail published | |
1da177e4 | 1798 | */ |
4edf1827 | 1799 | |
33f0f88f | 1800 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1801 | unsigned char __user **b, |
1802 | size_t *nr) | |
1803 | ||
1804 | { | |
53c5ee2c | 1805 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1806 | int retval; |
1807 | size_t n; | |
3fa10cc8 | 1808 | bool is_eof; |
bc5a5e3f | 1809 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1810 | |
1811 | retval = 0; | |
bc5a5e3f | 1812 | n = min(read_cnt(ldata), N_TTY_BUF_SIZE - tail); |
1da177e4 | 1813 | n = min(*nr, n); |
1da177e4 | 1814 | if (n) { |
bc5a5e3f | 1815 | retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
1da177e4 | 1816 | n -= retval; |
bc5a5e3f PH |
1817 | is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); |
1818 | tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, | |
53c5ee2c | 1819 | ldata->icanon); |
bc5a5e3f | 1820 | ldata->read_tail += n; |
26df6d13 | 1821 | /* Turn single EOF into zero-length read */ |
ce74117a | 1822 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !read_cnt(ldata)) |
3fa10cc8 | 1823 | n = 0; |
1da177e4 LT |
1824 | *b += n; |
1825 | *nr -= n; | |
1826 | } | |
1827 | return retval; | |
1828 | } | |
1829 | ||
88bb0de3 | 1830 | /** |
32f13521 | 1831 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1832 | * @tty: terminal device |
1833 | * @b: user data | |
1834 | * @nr: size of data | |
1835 | * | |
1836 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1837 | * it copies one line of input up to and including the line-delimiting |
1838 | * character into the user-space buffer. | |
88bb0de3 PH |
1839 | * |
1840 | * Called under the atomic_read_lock mutex | |
6d76bd26 PH |
1841 | * |
1842 | * n_tty_read()/consumer path: | |
1843 | * caller holds non-exclusive termios_rwsem | |
1844 | * read_tail published | |
88bb0de3 PH |
1845 | */ |
1846 | ||
32f13521 PH |
1847 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
1848 | unsigned char __user **b, | |
1849 | size_t *nr) | |
88bb0de3 PH |
1850 | { |
1851 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 1852 | size_t n, size, more, c; |
bc5a5e3f PH |
1853 | size_t eol; |
1854 | size_t tail; | |
1855 | int ret, found = 0; | |
88bb0de3 PH |
1856 | |
1857 | /* N.B. avoid overrun if nr == 0 */ | |
ce74117a | 1858 | n = min(*nr, read_cnt(ldata)); |
6d76bd26 | 1859 | if (!n) |
32f13521 | 1860 | return 0; |
88bb0de3 | 1861 | |
bc5a5e3f | 1862 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
1863 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
1864 | ||
bc5a5e3f | 1865 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
1866 | __func__, *nr, tail, n, size); |
1867 | ||
1868 | eol = find_next_bit(ldata->read_flags, size, tail); | |
1869 | more = n - (size - tail); | |
1870 | if (eol == N_TTY_BUF_SIZE && more) { | |
1871 | /* scan wrapped without finding set bit */ | |
1872 | eol = find_next_bit(ldata->read_flags, more, 0); | |
1873 | if (eol != more) | |
1874 | found = 1; | |
1875 | } else if (eol != size) | |
1876 | found = 1; | |
1877 | ||
1878 | size = N_TTY_BUF_SIZE - tail; | |
1879 | n = (found + eol + size) & (N_TTY_BUF_SIZE - 1); | |
1880 | c = n; | |
1881 | ||
bc5a5e3f | 1882 | if (found && read_buf(ldata, eol) == __DISABLED_CHAR) |
32f13521 PH |
1883 | n--; |
1884 | ||
bc5a5e3f | 1885 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", |
32f13521 PH |
1886 | __func__, eol, found, n, c, size, more); |
1887 | ||
32f13521 | 1888 | if (n > size) { |
bc5a5e3f | 1889 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), size); |
32f13521 PH |
1890 | if (ret) |
1891 | return -EFAULT; | |
1892 | ret = copy_to_user(*b + size, ldata->read_buf, n - size); | |
1893 | } else | |
bc5a5e3f | 1894 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
32f13521 PH |
1895 | |
1896 | if (ret) | |
1897 | return -EFAULT; | |
1898 | *b += n; | |
1899 | *nr -= n; | |
1900 | ||
a73d3d69 | 1901 | if (found) |
6d76bd26 PH |
1902 | clear_bit(eol, ldata->read_flags); |
1903 | smp_mb__after_clear_bit(); | |
1904 | ldata->read_tail += c; | |
88bb0de3 | 1905 | |
32f13521 PH |
1906 | if (found) |
1907 | tty_audit_push(tty); | |
88bb0de3 PH |
1908 | return 0; |
1909 | } | |
1910 | ||
cc4191dc | 1911 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1912 | size_t, loff_t *); |
1da177e4 LT |
1913 | |
1914 | /** | |
1915 | * job_control - check job control | |
1916 | * @tty: tty | |
1917 | * @file: file handle | |
1918 | * | |
1919 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1920 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1921 | * error code if action should be taken. |
04f378b1 | 1922 | * |
01a5e440 PH |
1923 | * Locking: redirected write test is safe |
1924 | * current->signal->tty check is safe | |
1925 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 1926 | */ |
4edf1827 | 1927 | |
1da177e4 LT |
1928 | static int job_control(struct tty_struct *tty, struct file *file) |
1929 | { | |
1930 | /* Job control check -- must be done at start and after | |
1931 | every sleep (POSIX.1 7.1.1.4). */ | |
1932 | /* NOTE: not yet done after every sleep pending a thorough | |
1933 | check of the logic of this change. -- jlc */ | |
1934 | /* don't stop on /dev/console */ | |
01a5e440 PH |
1935 | if (file->f_op->write == redirected_tty_write || |
1936 | current->signal->tty != tty) | |
1937 | return 0; | |
1938 | ||
1939 | spin_lock_irq(&tty->ctrl_lock); | |
1940 | if (!tty->pgrp) | |
1941 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
1942 | else if (task_pgrp(current) != tty->pgrp) { | |
1943 | spin_unlock_irq(&tty->ctrl_lock); | |
1944 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
1945 | return -EIO; | |
1946 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
1947 | set_thread_flag(TIF_SIGPENDING); | |
1948 | return -ERESTARTSYS; | |
1da177e4 | 1949 | } |
01a5e440 | 1950 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
1951 | return 0; |
1952 | } | |
4edf1827 | 1953 | |
1da177e4 LT |
1954 | |
1955 | /** | |
11a96d18 | 1956 | * n_tty_read - read function for tty |
1da177e4 LT |
1957 | * @tty: tty device |
1958 | * @file: file object | |
1959 | * @buf: userspace buffer pointer | |
1960 | * @nr: size of I/O | |
1961 | * | |
1962 | * Perform reads for the line discipline. We are guaranteed that the | |
1963 | * line discipline will not be closed under us but we may get multiple | |
1964 | * parallel readers and must handle this ourselves. We may also get | |
1965 | * a hangup. Always called in user context, may sleep. | |
1966 | * | |
1967 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
1968 | * |
1969 | * n_tty_read()/consumer path: | |
1970 | * claims non-exclusive termios_rwsem | |
1971 | * publishes read_tail | |
1da177e4 | 1972 | */ |
4edf1827 | 1973 | |
11a96d18 | 1974 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1975 | unsigned char __user *buf, size_t nr) |
1976 | { | |
53c5ee2c | 1977 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1978 | unsigned char __user *b = buf; |
1979 | DECLARE_WAITQUEUE(wait, current); | |
1980 | int c; | |
1981 | int minimum, time; | |
1982 | ssize_t retval = 0; | |
1983 | ssize_t size; | |
1984 | long timeout; | |
1985 | unsigned long flags; | |
04f378b1 | 1986 | int packet; |
1da177e4 LT |
1987 | |
1988 | do_it_again: | |
1da177e4 | 1989 | c = job_control(tty, file); |
4edf1827 | 1990 | if (c < 0) |
1da177e4 | 1991 | return c; |
4edf1827 | 1992 | |
9356b535 PH |
1993 | down_read(&tty->termios_rwsem); |
1994 | ||
1da177e4 LT |
1995 | minimum = time = 0; |
1996 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 1997 | if (!ldata->icanon) { |
1da177e4 LT |
1998 | minimum = MIN_CHAR(tty); |
1999 | if (minimum) { | |
a6e54319 | 2000 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2001 | if (time) |
f6c8dbe6 | 2002 | ldata->minimum_to_wake = 1; |
1da177e4 | 2003 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
2004 | (ldata->minimum_to_wake > minimum)) |
2005 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 2006 | } else { |
a6e54319 | 2007 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2008 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2009 | } |
2010 | } | |
2011 | ||
2012 | /* | |
2013 | * Internal serialization of reads. | |
2014 | */ | |
2015 | if (file->f_flags & O_NONBLOCK) { | |
9356b535 PH |
2016 | if (!mutex_trylock(&ldata->atomic_read_lock)) { |
2017 | up_read(&tty->termios_rwsem); | |
1da177e4 | 2018 | return -EAGAIN; |
9356b535 | 2019 | } |
4edf1827 | 2020 | } else { |
9356b535 PH |
2021 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) { |
2022 | up_read(&tty->termios_rwsem); | |
1da177e4 | 2023 | return -ERESTARTSYS; |
9356b535 | 2024 | } |
1da177e4 | 2025 | } |
04f378b1 | 2026 | packet = tty->packet; |
1da177e4 LT |
2027 | |
2028 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2029 | while (nr) { |
2030 | /* First test for status change. */ | |
04f378b1 | 2031 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2032 | unsigned char cs; |
2033 | if (b != buf) | |
2034 | break; | |
04f378b1 | 2035 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
2036 | cs = tty->link->ctrl_status; |
2037 | tty->link->ctrl_status = 0; | |
04f378b1 | 2038 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 2039 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2040 | retval = -EFAULT; |
2041 | b--; | |
2042 | break; | |
2043 | } | |
2044 | nr--; | |
2045 | break; | |
2046 | } | |
2047 | /* This statement must be first before checking for input | |
2048 | so that any interrupt will set the state back to | |
2049 | TASK_RUNNING. */ | |
2050 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 2051 | |
f6c8dbe6 | 2052 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2053 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2054 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2055 | |
1da177e4 LT |
2056 | if (!input_available_p(tty, 0)) { |
2057 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
2058 | retval = -EIO; | |
2059 | break; | |
2060 | } | |
2061 | if (tty_hung_up_p(file)) | |
2062 | break; | |
2063 | if (!timeout) | |
2064 | break; | |
2065 | if (file->f_flags & O_NONBLOCK) { | |
2066 | retval = -EAGAIN; | |
2067 | break; | |
2068 | } | |
2069 | if (signal_pending(current)) { | |
2070 | retval = -ERESTARTSYS; | |
2071 | break; | |
2072 | } | |
55db4c64 | 2073 | n_tty_set_room(tty); |
9356b535 PH |
2074 | up_read(&tty->termios_rwsem); |
2075 | ||
1da177e4 | 2076 | timeout = schedule_timeout(timeout); |
9356b535 PH |
2077 | |
2078 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2079 | continue; |
2080 | } | |
2081 | __set_current_state(TASK_RUNNING); | |
2082 | ||
2083 | /* Deal with packet mode. */ | |
04f378b1 | 2084 | if (packet && b == buf) { |
522ed776 | 2085 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
2086 | retval = -EFAULT; |
2087 | b--; | |
2088 | break; | |
2089 | } | |
2090 | nr--; | |
2091 | } | |
2092 | ||
53c5ee2c | 2093 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2094 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
1da177e4 LT |
2095 | if (retval) |
2096 | break; | |
2097 | } else { | |
2098 | int uncopied; | |
04f378b1 AC |
2099 | /* The copy function takes the read lock and handles |
2100 | locking internally for this case */ | |
1da177e4 LT |
2101 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2102 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2103 | if (uncopied) { | |
2104 | retval = -EFAULT; | |
2105 | break; | |
2106 | } | |
2107 | } | |
2108 | ||
6367ca72 | 2109 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2110 | |
2111 | if (b - buf >= minimum) | |
2112 | break; | |
2113 | if (time) | |
2114 | timeout = time; | |
2115 | } | |
bddc7152 | 2116 | mutex_unlock(&ldata->atomic_read_lock); |
1da177e4 LT |
2117 | remove_wait_queue(&tty->read_wait, &wait); |
2118 | ||
2119 | if (!waitqueue_active(&tty->read_wait)) | |
f6c8dbe6 | 2120 | ldata->minimum_to_wake = minimum; |
1da177e4 LT |
2121 | |
2122 | __set_current_state(TASK_RUNNING); | |
2123 | size = b - buf; | |
2124 | if (size) { | |
2125 | retval = size; | |
2126 | if (nr) | |
4edf1827 | 2127 | clear_bit(TTY_PUSH, &tty->flags); |
9356b535 PH |
2128 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) { |
2129 | up_read(&tty->termios_rwsem); | |
bbd20759 | 2130 | goto do_it_again; |
9356b535 | 2131 | } |
1da177e4 | 2132 | |
55db4c64 | 2133 | n_tty_set_room(tty); |
9356b535 | 2134 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2135 | return retval; |
2136 | } | |
2137 | ||
2138 | /** | |
11a96d18 | 2139 | * n_tty_write - write function for tty |
1da177e4 LT |
2140 | * @tty: tty device |
2141 | * @file: file object | |
2142 | * @buf: userspace buffer pointer | |
2143 | * @nr: size of I/O | |
2144 | * | |
a88a69c9 | 2145 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2146 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2147 | * and other such events. Since the receive code will echo characters, |
2148 | * thus calling driver write methods, the output_lock is used in | |
2149 | * the output processing functions called here as well as in the | |
2150 | * echo processing function to protect the column state and space | |
2151 | * left in the buffer. | |
1da177e4 LT |
2152 | * |
2153 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2154 | * |
2155 | * Locking: output_lock to protect column state and space left | |
2156 | * (note that the process_output*() functions take this | |
2157 | * lock themselves) | |
1da177e4 | 2158 | */ |
4edf1827 | 2159 | |
11a96d18 | 2160 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2161 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2162 | { |
2163 | const unsigned char *b = buf; | |
2164 | DECLARE_WAITQUEUE(wait, current); | |
2165 | int c; | |
2166 | ssize_t retval = 0; | |
2167 | ||
2168 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2169 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2170 | retval = tty_check_change(tty); | |
2171 | if (retval) | |
2172 | return retval; | |
2173 | } | |
2174 | ||
9356b535 PH |
2175 | down_read(&tty->termios_rwsem); |
2176 | ||
a88a69c9 JP |
2177 | /* Write out any echoed characters that are still pending */ |
2178 | process_echoes(tty); | |
300a6204 | 2179 | |
1da177e4 LT |
2180 | add_wait_queue(&tty->write_wait, &wait); |
2181 | while (1) { | |
2182 | set_current_state(TASK_INTERRUPTIBLE); | |
2183 | if (signal_pending(current)) { | |
2184 | retval = -ERESTARTSYS; | |
2185 | break; | |
2186 | } | |
2187 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2188 | retval = -EIO; | |
2189 | break; | |
2190 | } | |
582f5590 | 2191 | if (O_OPOST(tty)) { |
1da177e4 | 2192 | while (nr > 0) { |
a88a69c9 | 2193 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2194 | if (num < 0) { |
2195 | if (num == -EAGAIN) | |
2196 | break; | |
2197 | retval = num; | |
2198 | goto break_out; | |
2199 | } | |
2200 | b += num; | |
2201 | nr -= num; | |
2202 | if (nr == 0) | |
2203 | break; | |
2204 | c = *b; | |
a88a69c9 | 2205 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2206 | break; |
2207 | b++; nr--; | |
2208 | } | |
f34d7a5b AC |
2209 | if (tty->ops->flush_chars) |
2210 | tty->ops->flush_chars(tty); | |
1da177e4 | 2211 | } else { |
d6afe27b | 2212 | while (nr > 0) { |
f34d7a5b | 2213 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
2214 | if (c < 0) { |
2215 | retval = c; | |
2216 | goto break_out; | |
2217 | } | |
2218 | if (!c) | |
2219 | break; | |
2220 | b += c; | |
2221 | nr -= c; | |
1da177e4 | 2222 | } |
1da177e4 LT |
2223 | } |
2224 | if (!nr) | |
2225 | break; | |
2226 | if (file->f_flags & O_NONBLOCK) { | |
2227 | retval = -EAGAIN; | |
2228 | break; | |
2229 | } | |
9356b535 PH |
2230 | up_read(&tty->termios_rwsem); |
2231 | ||
1da177e4 | 2232 | schedule(); |
9356b535 PH |
2233 | |
2234 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2235 | } |
2236 | break_out: | |
2237 | __set_current_state(TASK_RUNNING); | |
2238 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2239 | if (b - buf != nr && tty->fasync) |
2240 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2241 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2242 | return (b - buf) ? b - buf : retval; |
2243 | } | |
2244 | ||
2245 | /** | |
11a96d18 | 2246 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2247 | * @tty: terminal device |
2248 | * @file: file accessing it | |
2249 | * @wait: poll table | |
2250 | * | |
2251 | * Called when the line discipline is asked to poll() for data or | |
2252 | * for special events. This code is not serialized with respect to | |
2253 | * other events save open/close. | |
2254 | * | |
2255 | * This code must be sure never to sleep through a hangup. | |
2256 | * Called without the kernel lock held - fine | |
1da177e4 | 2257 | */ |
4edf1827 | 2258 | |
11a96d18 | 2259 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2260 | poll_table *wait) |
1da177e4 | 2261 | { |
f6c8dbe6 | 2262 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2263 | unsigned int mask = 0; |
2264 | ||
2265 | poll_wait(file, &tty->read_wait, wait); | |
2266 | poll_wait(file, &tty->write_wait, wait); | |
2267 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2268 | mask |= POLLIN | POLLRDNORM; | |
2269 | if (tty->packet && tty->link->ctrl_status) | |
2270 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2271 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2272 | mask |= POLLHUP; | |
2273 | if (tty_hung_up_p(file)) | |
2274 | mask |= POLLHUP; | |
2275 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2276 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2277 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2278 | else |
f6c8dbe6 | 2279 | ldata->minimum_to_wake = 1; |
1da177e4 | 2280 | } |
f34d7a5b AC |
2281 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2282 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2283 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2284 | mask |= POLLOUT | POLLWRNORM; |
2285 | return mask; | |
2286 | } | |
2287 | ||
57c94121 | 2288 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2289 | { |
bc5a5e3f | 2290 | size_t nr, head, tail; |
47afa7a5 | 2291 | |
a73d3d69 | 2292 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2293 | return 0; |
ba2e68ac JS |
2294 | head = ldata->canon_head; |
2295 | tail = ldata->read_tail; | |
bc5a5e3f | 2296 | nr = head - tail; |
47afa7a5 AC |
2297 | /* Skip EOF-chars.. */ |
2298 | while (head != tail) { | |
bc5a5e3f PH |
2299 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2300 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2301 | nr--; |
bc5a5e3f | 2302 | tail++; |
47afa7a5 AC |
2303 | } |
2304 | return nr; | |
2305 | } | |
2306 | ||
2307 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2308 | unsigned int cmd, unsigned long arg) | |
2309 | { | |
ba2e68ac | 2310 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2311 | int retval; |
2312 | ||
2313 | switch (cmd) { | |
2314 | case TIOCOUTQ: | |
2315 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2316 | case TIOCINQ: | |
6d76bd26 | 2317 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2318 | if (L_ICANON(tty)) |
57c94121 | 2319 | retval = inq_canon(ldata); |
6d76bd26 PH |
2320 | else |
2321 | retval = read_cnt(ldata); | |
2322 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2323 | return put_user(retval, (unsigned int __user *) arg); |
2324 | default: | |
2325 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2326 | } | |
2327 | } | |
2328 | ||
f6c8dbe6 PH |
2329 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2330 | { | |
2331 | struct n_tty_data *ldata = tty->disc_data; | |
2332 | ||
2333 | if (!waitqueue_active(&tty->read_wait)) { | |
2334 | if (on) | |
2335 | ldata->minimum_to_wake = 1; | |
2336 | else if (!tty->fasync) | |
2337 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2338 | } | |
2339 | } | |
2340 | ||
a352def2 | 2341 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2342 | .magic = TTY_LDISC_MAGIC, |
2343 | .name = "n_tty", | |
2344 | .open = n_tty_open, | |
2345 | .close = n_tty_close, | |
2346 | .flush_buffer = n_tty_flush_buffer, | |
2347 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2348 | .read = n_tty_read, |
2349 | .write = n_tty_write, | |
e10cc1df PF |
2350 | .ioctl = n_tty_ioctl, |
2351 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2352 | .poll = n_tty_poll, |
e10cc1df | 2353 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2354 | .write_wakeup = n_tty_write_wakeup, |
2355 | .fasync = n_tty_fasync, | |
24a89d1c | 2356 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2357 | }; |
572b9adb RG |
2358 | |
2359 | /** | |
2360 | * n_tty_inherit_ops - inherit N_TTY methods | |
2361 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2362 | * | |
593fb1ae | 2363 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2364 | * methods. |
2365 | */ | |
2366 | ||
2367 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2368 | { | |
2369 | *ops = tty_ldisc_N_TTY; | |
2370 | ops->owner = NULL; | |
2371 | ops->refcount = ops->flags = 0; | |
2372 | } | |
2373 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |