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