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 | ||
cbfd0340 PH |
77 | #define ECHO_COMMIT_WATERMARK 256 |
78 | #define ECHO_BLOCK 256 | |
79 | #define ECHO_DISCARD_WATERMARK N_TTY_BUF_SIZE - (ECHO_BLOCK + 32) | |
80 | ||
81 | ||
32f13521 PH |
82 | #undef N_TTY_TRACE |
83 | #ifdef N_TTY_TRACE | |
84 | # define n_tty_trace(f, args...) trace_printk(f, ##args) | |
85 | #else | |
86 | # define n_tty_trace(f, args...) | |
87 | #endif | |
88 | ||
70ece7a7 | 89 | struct n_tty_data { |
fb7aa03d PH |
90 | /* producer-published */ |
91 | size_t read_head; | |
92 | size_t canon_head; | |
93 | DECLARE_BITMAP(process_char_map, 256); | |
94 | ||
95 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c JS |
96 | unsigned long overrun_time; |
97 | int num_overrun; | |
98 | ||
24a89d1c PH |
99 | /* non-atomic */ |
100 | bool no_room; | |
101 | ||
fb7aa03d | 102 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c | 103 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
3fe780b3 | 104 | |
fb7aa03d PH |
105 | /* shared by producer and consumer */ |
106 | char *read_buf; | |
3fe780b3 | 107 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
ba2e68ac | 108 | |
f6c8dbe6 | 109 | int minimum_to_wake; |
ba2e68ac | 110 | |
fb7aa03d PH |
111 | /* consumer-published */ |
112 | size_t read_tail; | |
113 | ||
ba2e68ac | 114 | unsigned char *echo_buf; |
addaebcc PH |
115 | size_t echo_head; |
116 | size_t echo_tail; | |
17bd7907 | 117 | size_t echo_commit; |
ba2e68ac | 118 | |
fb7aa03d PH |
119 | /* protected by output lock */ |
120 | unsigned int column; | |
ba2e68ac | 121 | unsigned int canon_column; |
bddc7152 JS |
122 | |
123 | struct mutex atomic_read_lock; | |
124 | struct mutex output_lock; | |
70ece7a7 JS |
125 | }; |
126 | ||
ce74117a PH |
127 | static inline size_t read_cnt(struct n_tty_data *ldata) |
128 | { | |
a2f73be8 | 129 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
130 | } |
131 | ||
bc5a5e3f PH |
132 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
133 | { | |
134 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
135 | } | |
136 | ||
137 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
138 | { | |
139 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
140 | } | |
141 | ||
addaebcc PH |
142 | static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) |
143 | { | |
144 | return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
145 | } | |
146 | ||
147 | static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) | |
148 | { | |
149 | return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
150 | } | |
151 | ||
522ed776 MT |
152 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
153 | unsigned char __user *ptr) | |
154 | { | |
53c5ee2c JS |
155 | struct n_tty_data *ldata = tty->disc_data; |
156 | ||
157 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
158 | return put_user(x, ptr); |
159 | } | |
160 | ||
24a89d1c | 161 | static int receive_room(struct tty_struct *tty) |
55db4c64 | 162 | { |
53c5ee2c | 163 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 164 | int left; |
55db4c64 | 165 | |
090abf7b JA |
166 | if (I_PARMRK(tty)) { |
167 | /* Multiply read_cnt by 3, since each byte might take up to | |
168 | * three times as many spaces when PARMRK is set (depending on | |
169 | * its flags, e.g. parity error). */ | |
ce74117a | 170 | left = N_TTY_BUF_SIZE - read_cnt(ldata) * 3 - 1; |
090abf7b | 171 | } else |
ce74117a | 172 | left = N_TTY_BUF_SIZE - read_cnt(ldata) - 1; |
090abf7b | 173 | |
55db4c64 LT |
174 | /* |
175 | * If we are doing input canonicalization, and there are no | |
176 | * pending newlines, let characters through without limit, so | |
177 | * that erase characters will be handled. Other excess | |
178 | * characters will be beeped. | |
179 | */ | |
180 | if (left <= 0) | |
a73d3d69 | 181 | left = ldata->icanon && ldata->canon_head == ldata->read_tail; |
55db4c64 | 182 | |
24a89d1c | 183 | return left; |
7879a9f9 PH |
184 | } |
185 | ||
24a89d1c PH |
186 | /** |
187 | * n_tty_set_room - receive space | |
188 | * @tty: terminal | |
189 | * | |
190 | * Re-schedules the flip buffer work if space just became available. | |
191 | * | |
6d76bd26 PH |
192 | * Caller holds exclusive termios_rwsem |
193 | * or | |
194 | * n_tty_read()/consumer path: | |
195 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
196 | */ |
197 | ||
7879a9f9 PH |
198 | static void n_tty_set_room(struct tty_struct *tty) |
199 | { | |
24a89d1c PH |
200 | struct n_tty_data *ldata = tty->disc_data; |
201 | ||
55db4c64 | 202 | /* Did this open up the receive buffer? We may need to flip */ |
24a89d1c PH |
203 | if (unlikely(ldata->no_room) && receive_room(tty)) { |
204 | ldata->no_room = 0; | |
205 | ||
ecbbfd44 | 206 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 207 | "scheduling with invalid itty\n"); |
21622939 PH |
208 | /* see if ldisc has been killed - if so, this means that |
209 | * even though the ldisc has been halted and ->buf.work | |
210 | * cancelled, ->buf.work is about to be rescheduled | |
211 | */ | |
212 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
213 | "scheduling buffer work for halted ldisc\n"); | |
f0f947c1 | 214 | queue_work(system_unbound_wq, &tty->port->buf.work); |
ecbbfd44 | 215 | } |
55db4c64 LT |
216 | } |
217 | ||
9a4aec2d PH |
218 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
219 | { | |
220 | struct n_tty_data *ldata = tty->disc_data; | |
221 | ssize_t n = 0; | |
222 | ||
223 | if (!ldata->icanon) | |
224 | n = read_cnt(ldata); | |
225 | else | |
226 | n = ldata->canon_head - ldata->read_tail; | |
227 | return n; | |
228 | } | |
229 | ||
ee0bab83 PH |
230 | /** |
231 | * n_tty_write_wakeup - asynchronous I/O notifier | |
232 | * @tty: tty device | |
233 | * | |
234 | * Required for the ptys, serial driver etc. since processes | |
235 | * that attach themselves to the master and rely on ASYNC | |
236 | * IO must be woken up | |
237 | */ | |
238 | ||
239 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
240 | { | |
241 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) | |
242 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
243 | } | |
244 | ||
6367ca72 PH |
245 | static inline void n_tty_check_throttle(struct tty_struct *tty) |
246 | { | |
3afb1b39 PH |
247 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) |
248 | return; | |
6367ca72 PH |
249 | /* |
250 | * Check the remaining room for the input canonicalization | |
251 | * mode. We don't want to throttle the driver if we're in | |
252 | * canonical mode and don't have a newline yet! | |
253 | */ | |
254 | while (1) { | |
255 | int throttled; | |
256 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
257 | if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) | |
258 | break; | |
259 | throttled = tty_throttle_safe(tty); | |
260 | if (!throttled) | |
261 | break; | |
262 | } | |
263 | __tty_set_flow_change(tty, 0); | |
264 | } | |
265 | ||
266 | static inline void n_tty_check_unthrottle(struct tty_struct *tty) | |
267 | { | |
3afb1b39 PH |
268 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
269 | tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { | |
270 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
271 | return; | |
272 | if (!tty->count) | |
273 | return; | |
274 | n_tty_set_room(tty); | |
275 | n_tty_write_wakeup(tty->link); | |
276 | wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); | |
277 | return; | |
278 | } | |
279 | ||
6367ca72 PH |
280 | /* If there is enough space in the read buffer now, let the |
281 | * low-level driver know. We use chars_in_buffer() to | |
282 | * check the buffer, as it now knows about canonical mode. | |
283 | * Otherwise, if the driver is throttled and the line is | |
284 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
285 | * we won't get any more characters. | |
286 | */ | |
287 | ||
288 | while (1) { | |
289 | int unthrottled; | |
290 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
291 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
292 | break; | |
293 | if (!tty->count) | |
294 | break; | |
295 | n_tty_set_room(tty); | |
296 | unthrottled = tty_unthrottle_safe(tty); | |
297 | if (!unthrottled) | |
298 | break; | |
299 | } | |
300 | __tty_set_flow_change(tty, 0); | |
301 | } | |
302 | ||
17b82060 AC |
303 | /** |
304 | * put_tty_queue - add character to tty | |
305 | * @c: character | |
57c94121 | 306 | * @ldata: n_tty data |
17b82060 | 307 | * |
6d76bd26 PH |
308 | * Add a character to the tty read_buf queue. |
309 | * | |
310 | * n_tty_receive_buf()/producer path: | |
311 | * caller holds non-exclusive termios_rwsem | |
312 | * modifies read_head | |
313 | * | |
314 | * read_head is only considered 'published' if canonical mode is | |
315 | * not active. | |
17b82060 AC |
316 | */ |
317 | ||
57c94121 | 318 | static void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 319 | { |
6d76bd26 PH |
320 | if (read_cnt(ldata) < N_TTY_BUF_SIZE) { |
321 | *read_buf_addr(ldata, ldata->read_head) = c; | |
322 | ldata->read_head++; | |
323 | } | |
1da177e4 LT |
324 | } |
325 | ||
1da177e4 LT |
326 | /** |
327 | * reset_buffer_flags - reset buffer state | |
328 | * @tty: terminal to reset | |
329 | * | |
25518c68 PH |
330 | * Reset the read buffer counters and clear the flags. |
331 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 332 | * |
6d76bd26 PH |
333 | * Locking: caller holds exclusive termios_rwsem |
334 | * (or locking is not required) | |
1da177e4 | 335 | */ |
a88a69c9 | 336 | |
b66f4fa5 | 337 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 338 | { |
a73d3d69 | 339 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 340 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
a88a69c9 | 341 | |
a73d3d69 | 342 | ldata->erasing = 0; |
3fe780b3 | 343 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
1da177e4 LT |
344 | } |
345 | ||
a30737ab PH |
346 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
347 | { | |
348 | unsigned long flags; | |
349 | ||
350 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
351 | if (tty->link->packet) { | |
352 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
353 | wake_up_interruptible(&tty->link->read_wait); | |
354 | } | |
355 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
356 | } | |
357 | ||
1da177e4 LT |
358 | /** |
359 | * n_tty_flush_buffer - clean input queue | |
360 | * @tty: terminal device | |
361 | * | |
25518c68 PH |
362 | * Flush the input buffer. Called when the tty layer wants the |
363 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
364 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 365 | * |
6d76bd26 PH |
366 | * Holds termios_rwsem to exclude producer/consumer while |
367 | * buffer indices are reset. | |
368 | * | |
369 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 370 | */ |
4edf1827 AC |
371 | |
372 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 373 | { |
6d76bd26 | 374 | down_write(&tty->termios_rwsem); |
b66f4fa5 PH |
375 | reset_buffer_flags(tty->disc_data); |
376 | n_tty_set_room(tty); | |
4edf1827 | 377 | |
a30737ab PH |
378 | if (tty->link) |
379 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 380 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
381 | } |
382 | ||
6d76bd26 PH |
383 | /** |
384 | * n_tty_chars_in_buffer - report available bytes | |
385 | * @tty: tty device | |
386 | * | |
387 | * Report the number of characters buffered to be delivered to user | |
388 | * at this instant in time. | |
389 | * | |
390 | * Locking: exclusive termios_rwsem | |
391 | */ | |
392 | ||
a19d0c6a PH |
393 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
394 | { | |
6d76bd26 PH |
395 | ssize_t n; |
396 | ||
47534084 | 397 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
6d76bd26 PH |
398 | |
399 | down_write(&tty->termios_rwsem); | |
400 | n = chars_in_buffer(tty); | |
401 | up_write(&tty->termios_rwsem); | |
402 | return n; | |
a19d0c6a PH |
403 | } |
404 | ||
1da177e4 LT |
405 | /** |
406 | * is_utf8_continuation - utf8 multibyte check | |
407 | * @c: byte to check | |
408 | * | |
409 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
410 | * character. We use this to correctly compute the on screen size | |
411 | * of the character when printing | |
412 | */ | |
4edf1827 | 413 | |
1da177e4 LT |
414 | static inline int is_utf8_continuation(unsigned char c) |
415 | { | |
416 | return (c & 0xc0) == 0x80; | |
417 | } | |
418 | ||
419 | /** | |
420 | * is_continuation - multibyte check | |
421 | * @c: byte to check | |
422 | * | |
423 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
424 | * character and the terminal is in unicode mode. | |
425 | */ | |
4edf1827 | 426 | |
1da177e4 LT |
427 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
428 | { | |
429 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
430 | } | |
431 | ||
432 | /** | |
a88a69c9 | 433 | * do_output_char - output one character |
1da177e4 LT |
434 | * @c: character (or partial unicode symbol) |
435 | * @tty: terminal device | |
a88a69c9 | 436 | * @space: space available in tty driver write buffer |
1da177e4 | 437 | * |
a88a69c9 JP |
438 | * This is a helper function that handles one output character |
439 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
440 | * doing OPOST processing and putting the results in the |
441 | * tty driver's write buffer. | |
a88a69c9 JP |
442 | * |
443 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
444 | * and NLDLY. They simply aren't relevant in the world today. | |
445 | * If you ever need them, add them here. | |
1da177e4 | 446 | * |
a88a69c9 JP |
447 | * Returns the number of bytes of buffer space used or -1 if |
448 | * no space left. | |
449 | * | |
450 | * Locking: should be called under the output_lock to protect | |
451 | * the column state and space left in the buffer | |
1da177e4 | 452 | */ |
4edf1827 | 453 | |
a88a69c9 | 454 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 455 | { |
53c5ee2c | 456 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 457 | int spaces; |
1da177e4 | 458 | |
1da177e4 LT |
459 | if (!space) |
460 | return -1; | |
300a6204 | 461 | |
a88a69c9 JP |
462 | switch (c) { |
463 | case '\n': | |
464 | if (O_ONLRET(tty)) | |
53c5ee2c | 465 | ldata->column = 0; |
a88a69c9 JP |
466 | if (O_ONLCR(tty)) { |
467 | if (space < 2) | |
468 | return -1; | |
ba2e68ac | 469 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 470 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
471 | return 2; |
472 | } | |
ba2e68ac | 473 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
474 | break; |
475 | case '\r': | |
53c5ee2c | 476 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
477 | return 0; |
478 | if (O_OCRNL(tty)) { | |
479 | c = '\n'; | |
480 | if (O_ONLRET(tty)) | |
ba2e68ac | 481 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 482 | break; |
a88a69c9 | 483 | } |
ba2e68ac | 484 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
485 | break; |
486 | case '\t': | |
53c5ee2c | 487 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
488 | if (O_TABDLY(tty) == XTABS) { |
489 | if (space < spaces) | |
490 | return -1; | |
53c5ee2c | 491 | ldata->column += spaces; |
a88a69c9 JP |
492 | tty->ops->write(tty, " ", spaces); |
493 | return spaces; | |
1da177e4 | 494 | } |
53c5ee2c | 495 | ldata->column += spaces; |
a88a69c9 JP |
496 | break; |
497 | case '\b': | |
53c5ee2c JS |
498 | if (ldata->column > 0) |
499 | ldata->column--; | |
a88a69c9 JP |
500 | break; |
501 | default: | |
a59c0d6f JP |
502 | if (!iscntrl(c)) { |
503 | if (O_OLCUC(tty)) | |
504 | c = toupper(c); | |
505 | if (!is_continuation(c, tty)) | |
53c5ee2c | 506 | ldata->column++; |
a59c0d6f | 507 | } |
a88a69c9 | 508 | break; |
1da177e4 | 509 | } |
a88a69c9 | 510 | |
f34d7a5b | 511 | tty_put_char(tty, c); |
a88a69c9 JP |
512 | return 1; |
513 | } | |
514 | ||
515 | /** | |
516 | * process_output - output post processor | |
517 | * @c: character (or partial unicode symbol) | |
518 | * @tty: terminal device | |
519 | * | |
ee5aa7b8 JP |
520 | * Output one character with OPOST processing. |
521 | * Returns -1 when the output device is full and the character | |
522 | * must be retried. | |
a88a69c9 JP |
523 | * |
524 | * Locking: output_lock to protect column state and space left | |
525 | * (also, this is called from n_tty_write under the | |
526 | * tty layer write lock) | |
527 | */ | |
528 | ||
529 | static int process_output(unsigned char c, struct tty_struct *tty) | |
530 | { | |
bddc7152 | 531 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
532 | int space, retval; |
533 | ||
bddc7152 | 534 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
535 | |
536 | space = tty_write_room(tty); | |
537 | retval = do_output_char(c, tty, space); | |
538 | ||
bddc7152 | 539 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
540 | if (retval < 0) |
541 | return -1; | |
542 | else | |
543 | return 0; | |
1da177e4 LT |
544 | } |
545 | ||
546 | /** | |
a88a69c9 | 547 | * process_output_block - block post processor |
1da177e4 | 548 | * @tty: terminal device |
ee5aa7b8 JP |
549 | * @buf: character buffer |
550 | * @nr: number of bytes to output | |
551 | * | |
552 | * Output a block of characters with OPOST processing. | |
553 | * Returns the number of characters output. | |
1da177e4 LT |
554 | * |
555 | * This path is used to speed up block console writes, among other | |
556 | * things when processing blocks of output data. It handles only | |
557 | * the simple cases normally found and helps to generate blocks of | |
558 | * symbols for the console driver and thus improve performance. | |
559 | * | |
a88a69c9 JP |
560 | * Locking: output_lock to protect column state and space left |
561 | * (also, this is called from n_tty_write under the | |
562 | * tty layer write lock) | |
1da177e4 | 563 | */ |
4edf1827 | 564 | |
a88a69c9 JP |
565 | static ssize_t process_output_block(struct tty_struct *tty, |
566 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 567 | { |
53c5ee2c | 568 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 569 | int space; |
bbd20759 | 570 | int i; |
1da177e4 LT |
571 | const unsigned char *cp; |
572 | ||
bddc7152 | 573 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 574 | |
f34d7a5b | 575 | space = tty_write_room(tty); |
300a6204 | 576 | if (!space) { |
bddc7152 | 577 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 578 | return 0; |
a88a69c9 | 579 | } |
1da177e4 LT |
580 | if (nr > space) |
581 | nr = space; | |
582 | ||
583 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
584 | unsigned char c = *cp; |
585 | ||
586 | switch (c) { | |
1da177e4 LT |
587 | case '\n': |
588 | if (O_ONLRET(tty)) | |
53c5ee2c | 589 | ldata->column = 0; |
1da177e4 LT |
590 | if (O_ONLCR(tty)) |
591 | goto break_out; | |
ba2e68ac | 592 | ldata->canon_column = ldata->column; |
1da177e4 LT |
593 | break; |
594 | case '\r': | |
53c5ee2c | 595 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
596 | goto break_out; |
597 | if (O_OCRNL(tty)) | |
598 | goto break_out; | |
ba2e68ac | 599 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
600 | break; |
601 | case '\t': | |
602 | goto break_out; | |
603 | case '\b': | |
53c5ee2c JS |
604 | if (ldata->column > 0) |
605 | ldata->column--; | |
1da177e4 LT |
606 | break; |
607 | default: | |
a59c0d6f JP |
608 | if (!iscntrl(c)) { |
609 | if (O_OLCUC(tty)) | |
610 | goto break_out; | |
611 | if (!is_continuation(c, tty)) | |
53c5ee2c | 612 | ldata->column++; |
a59c0d6f | 613 | } |
1da177e4 LT |
614 | break; |
615 | } | |
616 | } | |
617 | break_out: | |
f34d7a5b | 618 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 619 | |
bddc7152 | 620 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
621 | return i; |
622 | } | |
623 | ||
a88a69c9 JP |
624 | /** |
625 | * process_echoes - write pending echo characters | |
626 | * @tty: terminal device | |
627 | * | |
628 | * Write previously buffered echo (and other ldisc-generated) | |
629 | * characters to the tty. | |
630 | * | |
631 | * Characters generated by the ldisc (including echoes) need to | |
632 | * be buffered because the driver's write buffer can fill during | |
633 | * heavy program output. Echoing straight to the driver will | |
634 | * often fail under these conditions, causing lost characters and | |
635 | * resulting mismatches of ldisc state information. | |
636 | * | |
637 | * Since the ldisc state must represent the characters actually sent | |
638 | * to the driver at the time of the write, operations like certain | |
639 | * changes in column state are also saved in the buffer and executed | |
640 | * here. | |
641 | * | |
642 | * A circular fifo buffer is used so that the most recent characters | |
643 | * are prioritized. Also, when control characters are echoed with a | |
644 | * prefixed "^", the pair is treated atomically and thus not separated. | |
645 | * | |
019ebdf9 | 646 | * Locking: callers must hold output_lock |
a88a69c9 JP |
647 | */ |
648 | ||
bc5b1ec5 | 649 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 650 | { |
53c5ee2c | 651 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 652 | int space, old_space; |
addaebcc | 653 | size_t tail; |
a88a69c9 | 654 | unsigned char c; |
a88a69c9 | 655 | |
bc5b1ec5 | 656 | old_space = space = tty_write_room(tty); |
a88a69c9 | 657 | |
addaebcc | 658 | tail = ldata->echo_tail; |
17bd7907 | 659 | nr = ldata->echo_commit - ldata->echo_tail; |
a88a69c9 | 660 | while (nr > 0) { |
addaebcc | 661 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
662 | if (c == ECHO_OP_START) { |
663 | unsigned char op; | |
a88a69c9 JP |
664 | int no_space_left = 0; |
665 | ||
666 | /* | |
667 | * If the buffer byte is the start of a multi-byte | |
668 | * operation, get the next byte, which is either the | |
669 | * op code or a control character value. | |
670 | */ | |
addaebcc | 671 | op = echo_buf(ldata, tail + 1); |
300a6204 | 672 | |
a88a69c9 JP |
673 | switch (op) { |
674 | unsigned int num_chars, num_bs; | |
675 | ||
676 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 677 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
678 | |
679 | /* | |
680 | * Determine how many columns to go back | |
681 | * in order to erase the tab. | |
682 | * This depends on the number of columns | |
683 | * used by other characters within the tab | |
684 | * area. If this (modulo 8) count is from | |
685 | * the start of input rather than from a | |
686 | * previous tab, we offset by canon column. | |
687 | * Otherwise, tab spacing is normal. | |
688 | */ | |
689 | if (!(num_chars & 0x80)) | |
ba2e68ac | 690 | num_chars += ldata->canon_column; |
a88a69c9 JP |
691 | num_bs = 8 - (num_chars & 7); |
692 | ||
693 | if (num_bs > space) { | |
694 | no_space_left = 1; | |
695 | break; | |
696 | } | |
697 | space -= num_bs; | |
698 | while (num_bs--) { | |
699 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
700 | if (ldata->column > 0) |
701 | ldata->column--; | |
a88a69c9 | 702 | } |
addaebcc | 703 | tail += 3; |
a88a69c9 JP |
704 | nr -= 3; |
705 | break; | |
706 | ||
707 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 708 | ldata->canon_column = ldata->column; |
addaebcc | 709 | tail += 2; |
a88a69c9 JP |
710 | nr -= 2; |
711 | break; | |
712 | ||
713 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
714 | if (ldata->column > 0) |
715 | ldata->column--; | |
addaebcc | 716 | tail += 2; |
a88a69c9 JP |
717 | nr -= 2; |
718 | break; | |
719 | ||
720 | case ECHO_OP_START: | |
721 | /* This is an escaped echo op start code */ | |
722 | if (!space) { | |
723 | no_space_left = 1; | |
724 | break; | |
725 | } | |
726 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 727 | ldata->column++; |
a88a69c9 | 728 | space--; |
addaebcc | 729 | tail += 2; |
a88a69c9 JP |
730 | nr -= 2; |
731 | break; | |
732 | ||
733 | default: | |
a88a69c9 | 734 | /* |
62b26358 JP |
735 | * If the op is not a special byte code, |
736 | * it is a ctrl char tagged to be echoed | |
737 | * as "^X" (where X is the letter | |
738 | * representing the control char). | |
739 | * Note that we must ensure there is | |
740 | * enough space for the whole ctrl pair. | |
741 | * | |
a88a69c9 | 742 | */ |
62b26358 JP |
743 | if (space < 2) { |
744 | no_space_left = 1; | |
745 | break; | |
746 | } | |
747 | tty_put_char(tty, '^'); | |
748 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 749 | ldata->column += 2; |
62b26358 | 750 | space -= 2; |
addaebcc | 751 | tail += 2; |
a88a69c9 JP |
752 | nr -= 2; |
753 | } | |
754 | ||
755 | if (no_space_left) | |
756 | break; | |
757 | } else { | |
582f5590 | 758 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
759 | int retval = do_output_char(c, tty, space); |
760 | if (retval < 0) | |
761 | break; | |
762 | space -= retval; | |
763 | } else { | |
764 | if (!space) | |
765 | break; | |
766 | tty_put_char(tty, c); | |
767 | space -= 1; | |
768 | } | |
addaebcc | 769 | tail += 1; |
a88a69c9 JP |
770 | nr -= 1; |
771 | } | |
a88a69c9 JP |
772 | } |
773 | ||
cbfd0340 PH |
774 | /* If the echo buffer is nearly full (so that the possibility exists |
775 | * of echo overrun before the next commit), then discard enough | |
776 | * data at the tail to prevent a subsequent overrun */ | |
777 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
778 | if (echo_buf(ldata, tail == ECHO_OP_START)) { | |
779 | if (echo_buf(ldata, tail) == ECHO_OP_ERASE_TAB) | |
780 | tail += 3; | |
781 | else | |
782 | tail += 2; | |
783 | } else | |
784 | tail++; | |
785 | } | |
786 | ||
addaebcc | 787 | ldata->echo_tail = tail; |
bc5b1ec5 | 788 | return old_space - space; |
019ebdf9 PH |
789 | } |
790 | ||
791 | static void commit_echoes(struct tty_struct *tty) | |
792 | { | |
793 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 794 | size_t nr, old, echoed; |
cbfd0340 PH |
795 | size_t head; |
796 | ||
797 | head = ldata->echo_head; | |
798 | old = ldata->echo_commit - ldata->echo_tail; | |
799 | ||
800 | /* Process committed echoes if the accumulated # of bytes | |
801 | * is over the threshold (and try again each time another | |
802 | * block is accumulated) */ | |
803 | nr = head - ldata->echo_tail; | |
804 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
805 | return; | |
a88a69c9 | 806 | |
019ebdf9 | 807 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 808 | ldata->echo_commit = head; |
bc5b1ec5 | 809 | echoed = __process_echoes(tty); |
bddc7152 | 810 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 811 | |
bc5b1ec5 | 812 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
813 | tty->ops->flush_chars(tty); |
814 | } | |
815 | ||
019ebdf9 | 816 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
817 | { |
818 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 819 | size_t echoed; |
17bd7907 | 820 | |
019ebdf9 PH |
821 | if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_tail) |
822 | return; | |
823 | ||
824 | mutex_lock(&ldata->output_lock); | |
bc5b1ec5 | 825 | echoed = __process_echoes(tty); |
019ebdf9 PH |
826 | mutex_unlock(&ldata->output_lock); |
827 | ||
bc5b1ec5 | 828 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 829 | tty->ops->flush_chars(tty); |
17bd7907 PH |
830 | } |
831 | ||
cbfd0340 PH |
832 | static void flush_echoes(struct tty_struct *tty) |
833 | { | |
834 | struct n_tty_data *ldata = tty->disc_data; | |
835 | ||
836 | if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_head) | |
837 | return; | |
838 | ||
839 | mutex_lock(&ldata->output_lock); | |
840 | ldata->echo_commit = ldata->echo_head; | |
841 | __process_echoes(tty); | |
842 | mutex_unlock(&ldata->output_lock); | |
843 | } | |
844 | ||
a88a69c9 JP |
845 | /** |
846 | * add_echo_byte - add a byte to the echo buffer | |
847 | * @c: unicode byte to echo | |
57c94121 | 848 | * @ldata: n_tty data |
a88a69c9 JP |
849 | * |
850 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
851 | */ |
852 | ||
cbfd0340 | 853 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 854 | { |
addaebcc | 855 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
856 | } |
857 | ||
858 | /** | |
859 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 860 | * @ldata: n_tty data |
a88a69c9 JP |
861 | * |
862 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
863 | */ |
864 | ||
57c94121 | 865 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 866 | { |
57c94121 JS |
867 | add_echo_byte(ECHO_OP_START, ldata); |
868 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
869 | } |
870 | ||
871 | /** | |
872 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 873 | * @ldata: n_tty data |
a88a69c9 JP |
874 | * |
875 | * Add an operation to the echo buffer to set the canon column | |
876 | * to the current column. | |
a88a69c9 JP |
877 | */ |
878 | ||
57c94121 | 879 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 880 | { |
57c94121 JS |
881 | add_echo_byte(ECHO_OP_START, ldata); |
882 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
883 | } |
884 | ||
885 | /** | |
886 | * echo_erase_tab - add operation to erase a tab | |
887 | * @num_chars: number of character columns already used | |
888 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 889 | * @ldata: n_tty data |
a88a69c9 JP |
890 | * |
891 | * Add an operation to the echo buffer to erase a tab. | |
892 | * | |
893 | * Called by the eraser function, which knows how many character | |
894 | * columns have been used since either a previous tab or the start | |
895 | * of input. This information will be used later, along with | |
896 | * canon column (if applicable), to go back the correct number | |
897 | * of columns. | |
a88a69c9 JP |
898 | */ |
899 | ||
900 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 901 | struct n_tty_data *ldata) |
a88a69c9 | 902 | { |
57c94121 JS |
903 | add_echo_byte(ECHO_OP_START, ldata); |
904 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
905 | |
906 | /* We only need to know this modulo 8 (tab spacing) */ | |
907 | num_chars &= 7; | |
908 | ||
909 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
910 | if (after_tab) | |
911 | num_chars |= 0x80; | |
300a6204 | 912 | |
57c94121 | 913 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
914 | } |
915 | ||
916 | /** | |
917 | * echo_char_raw - echo a character raw | |
918 | * @c: unicode byte to echo | |
919 | * @tty: terminal device | |
920 | * | |
921 | * Echo user input back onto the screen. This must be called only when | |
922 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
923 | * | |
924 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
925 | */ |
926 | ||
57c94121 | 927 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 928 | { |
a88a69c9 | 929 | if (c == ECHO_OP_START) { |
57c94121 JS |
930 | add_echo_byte(ECHO_OP_START, ldata); |
931 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 932 | } else { |
57c94121 | 933 | add_echo_byte(c, ldata); |
a88a69c9 | 934 | } |
a88a69c9 | 935 | } |
1da177e4 | 936 | |
1da177e4 | 937 | /** |
a88a69c9 | 938 | * echo_char - echo a character |
1da177e4 LT |
939 | * @c: unicode byte to echo |
940 | * @tty: terminal device | |
941 | * | |
4edf1827 | 942 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 943 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 944 | * |
62b26358 JP |
945 | * This variant tags control characters to be echoed as "^X" |
946 | * (where X is the letter representing the control char). | |
1da177e4 LT |
947 | */ |
948 | ||
949 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
950 | { | |
bddc7152 JS |
951 | struct n_tty_data *ldata = tty->disc_data; |
952 | ||
a88a69c9 | 953 | if (c == ECHO_OP_START) { |
57c94121 JS |
954 | add_echo_byte(ECHO_OP_START, ldata); |
955 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 956 | } else { |
62b26358 | 957 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
958 | add_echo_byte(ECHO_OP_START, ldata); |
959 | add_echo_byte(c, ldata); | |
a88a69c9 | 960 | } |
1da177e4 LT |
961 | } |
962 | ||
17b82060 | 963 | /** |
a88a69c9 | 964 | * finish_erasing - complete erase |
57c94121 | 965 | * @ldata: n_tty data |
17b82060 | 966 | */ |
a88a69c9 | 967 | |
57c94121 | 968 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 969 | { |
53c5ee2c | 970 | if (ldata->erasing) { |
57c94121 | 971 | echo_char_raw('/', ldata); |
53c5ee2c | 972 | ldata->erasing = 0; |
1da177e4 LT |
973 | } |
974 | } | |
975 | ||
976 | /** | |
977 | * eraser - handle erase function | |
978 | * @c: character input | |
979 | * @tty: terminal device | |
980 | * | |
3a4fa0a2 | 981 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
982 | * present in the stream from the driver layer. Handles the complexities |
983 | * of UTF-8 multibyte symbols. | |
17b82060 | 984 | * |
6d76bd26 PH |
985 | * n_tty_receive_buf()/producer path: |
986 | * caller holds non-exclusive termios_rwsem | |
987 | * modifies read_head | |
988 | * | |
989 | * Modifying the read_head is not considered a publish in this context | |
990 | * because canonical mode is active -- only canon_head publishes | |
1da177e4 | 991 | */ |
4edf1827 | 992 | |
1da177e4 LT |
993 | static void eraser(unsigned char c, struct tty_struct *tty) |
994 | { | |
53c5ee2c | 995 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 996 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
997 | size_t head; |
998 | size_t cnt; | |
999 | int seen_alnums; | |
1da177e4 | 1000 | |
ba2e68ac | 1001 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 1002 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
1003 | return; |
1004 | } | |
1005 | if (c == ERASE_CHAR(tty)) | |
1006 | kill_type = ERASE; | |
1007 | else if (c == WERASE_CHAR(tty)) | |
1008 | kill_type = WERASE; | |
1009 | else { | |
1010 | if (!L_ECHO(tty)) { | |
ba2e68ac | 1011 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
1012 | return; |
1013 | } | |
1014 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 1015 | ldata->read_head = ldata->canon_head; |
57c94121 | 1016 | finish_erasing(ldata); |
1da177e4 LT |
1017 | echo_char(KILL_CHAR(tty), tty); |
1018 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
1019 | if (L_ECHOK(tty)) | |
57c94121 | 1020 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1021 | return; |
1022 | } | |
1023 | kill_type = KILL; | |
1024 | } | |
1025 | ||
1026 | seen_alnums = 0; | |
ba2e68ac JS |
1027 | while (ldata->read_head != ldata->canon_head) { |
1028 | head = ldata->read_head; | |
1da177e4 LT |
1029 | |
1030 | /* erase a single possibly multibyte character */ | |
1031 | do { | |
bc5a5e3f PH |
1032 | head--; |
1033 | c = read_buf(ldata, head); | |
ba2e68ac | 1034 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1035 | |
1036 | /* do not partially erase */ | |
1037 | if (is_continuation(c, tty)) | |
1038 | break; | |
1039 | ||
1040 | if (kill_type == WERASE) { | |
1041 | /* Equivalent to BSD's ALTWERASE. */ | |
1042 | if (isalnum(c) || c == '_') | |
1043 | seen_alnums++; | |
1044 | else if (seen_alnums) | |
1045 | break; | |
1046 | } | |
bc5a5e3f | 1047 | cnt = ldata->read_head - head; |
ba2e68ac | 1048 | ldata->read_head = head; |
1da177e4 LT |
1049 | if (L_ECHO(tty)) { |
1050 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1051 | if (!ldata->erasing) { |
57c94121 | 1052 | echo_char_raw('\\', ldata); |
53c5ee2c | 1053 | ldata->erasing = 1; |
1da177e4 LT |
1054 | } |
1055 | /* if cnt > 1, output a multi-byte character */ | |
1056 | echo_char(c, tty); | |
1057 | while (--cnt > 0) { | |
bc5a5e3f PH |
1058 | head++; |
1059 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1060 | echo_move_back_col(ldata); |
1da177e4 LT |
1061 | } |
1062 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1063 | echo_char(ERASE_CHAR(tty), tty); | |
1064 | } else if (c == '\t') { | |
a88a69c9 JP |
1065 | unsigned int num_chars = 0; |
1066 | int after_tab = 0; | |
bc5a5e3f | 1067 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1068 | |
1069 | /* | |
1070 | * Count the columns used for characters | |
1071 | * since the start of input or after a | |
1072 | * previous tab. | |
1073 | * This info is used to go back the correct | |
1074 | * number of columns. | |
1075 | */ | |
ba2e68ac | 1076 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1077 | tail--; |
1078 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1079 | if (c == '\t') { |
1080 | after_tab = 1; | |
1081 | break; | |
300a6204 | 1082 | } else if (iscntrl(c)) { |
1da177e4 | 1083 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1084 | num_chars += 2; |
1085 | } else if (!is_continuation(c, tty)) { | |
1086 | num_chars++; | |
1087 | } | |
1da177e4 | 1088 | } |
57c94121 | 1089 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1090 | } else { |
1091 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1092 | echo_char_raw('\b', ldata); |
1093 | echo_char_raw(' ', ldata); | |
1094 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1095 | } |
1096 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1097 | echo_char_raw('\b', ldata); |
1098 | echo_char_raw(' ', ldata); | |
1099 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1100 | } |
1101 | } | |
1102 | } | |
1103 | if (kill_type == ERASE) | |
1104 | break; | |
1105 | } | |
ba2e68ac | 1106 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1107 | finish_erasing(ldata); |
1da177e4 LT |
1108 | } |
1109 | ||
1110 | /** | |
1111 | * isig - handle the ISIG optio | |
1112 | * @sig: signal | |
1113 | * @tty: terminal | |
1da177e4 | 1114 | * |
8c985d18 PH |
1115 | * Called when a signal is being sent due to terminal input. |
1116 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1117 | * |
8c985d18 | 1118 | * Locking: ctrl_lock |
1da177e4 | 1119 | */ |
4edf1827 | 1120 | |
8c985d18 | 1121 | static inline void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1122 | { |
8c985d18 PH |
1123 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1124 | if (tty_pgrp) { | |
1125 | kill_pgrp(tty_pgrp, sig, 1); | |
1126 | put_pid(tty_pgrp); | |
1da177e4 LT |
1127 | } |
1128 | } | |
1129 | ||
1130 | /** | |
1131 | * n_tty_receive_break - handle break | |
1132 | * @tty: terminal | |
1133 | * | |
1134 | * An RS232 break event has been hit in the incoming bitstream. This | |
1135 | * can cause a variety of events depending upon the termios settings. | |
1136 | * | |
6d76bd26 PH |
1137 | * n_tty_receive_buf()/producer path: |
1138 | * caller holds non-exclusive termios_rwsem | |
1139 | * publishes read_head via put_tty_queue() | |
1140 | * | |
1141 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1142 | */ |
4edf1827 | 1143 | |
1da177e4 LT |
1144 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1145 | { | |
57c94121 JS |
1146 | struct n_tty_data *ldata = tty->disc_data; |
1147 | ||
1da177e4 LT |
1148 | if (I_IGNBRK(tty)) |
1149 | return; | |
1150 | if (I_BRKINT(tty)) { | |
8c985d18 PH |
1151 | isig(SIGINT, tty); |
1152 | if (!L_NOFLSH(tty)) { | |
6d76bd26 PH |
1153 | /* flushing needs exclusive termios_rwsem */ |
1154 | up_read(&tty->termios_rwsem); | |
8c985d18 PH |
1155 | n_tty_flush_buffer(tty); |
1156 | tty_driver_flush_buffer(tty); | |
6d76bd26 | 1157 | down_read(&tty->termios_rwsem); |
8c985d18 | 1158 | } |
1da177e4 LT |
1159 | return; |
1160 | } | |
1161 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1162 | put_tty_queue('\377', ldata); |
1163 | put_tty_queue('\0', ldata); | |
1da177e4 | 1164 | } |
57c94121 | 1165 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1166 | wake_up_interruptible(&tty->read_wait); |
1167 | } | |
1168 | ||
1169 | /** | |
1170 | * n_tty_receive_overrun - handle overrun reporting | |
1171 | * @tty: terminal | |
1172 | * | |
1173 | * Data arrived faster than we could process it. While the tty | |
1174 | * driver has flagged this the bits that were missed are gone | |
1175 | * forever. | |
1176 | * | |
1177 | * Called from the receive_buf path so single threaded. Does not | |
1178 | * need locking as num_overrun and overrun_time are function | |
1179 | * private. | |
1180 | */ | |
4edf1827 | 1181 | |
1da177e4 LT |
1182 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1183 | { | |
53c5ee2c | 1184 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1185 | char buf[64]; |
1186 | ||
53c5ee2c JS |
1187 | ldata->num_overrun++; |
1188 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1189 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1190 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1191 | tty_name(tty, buf), | |
53c5ee2c JS |
1192 | ldata->num_overrun); |
1193 | ldata->overrun_time = jiffies; | |
1194 | ldata->num_overrun = 0; | |
1da177e4 LT |
1195 | } |
1196 | } | |
1197 | ||
1198 | /** | |
1199 | * n_tty_receive_parity_error - error notifier | |
1200 | * @tty: terminal device | |
1201 | * @c: character | |
1202 | * | |
1203 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1204 | * the error case if necessary. |
1205 | * | |
1206 | * n_tty_receive_buf()/producer path: | |
1207 | * caller holds non-exclusive termios_rwsem | |
1208 | * publishes read_head via put_tty_queue() | |
1da177e4 LT |
1209 | */ |
1210 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1211 | unsigned char c) | |
1212 | { | |
57c94121 JS |
1213 | struct n_tty_data *ldata = tty->disc_data; |
1214 | ||
4edf1827 | 1215 | if (I_IGNPAR(tty)) |
1da177e4 | 1216 | return; |
1da177e4 | 1217 | if (I_PARMRK(tty)) { |
57c94121 JS |
1218 | put_tty_queue('\377', ldata); |
1219 | put_tty_queue('\0', ldata); | |
1220 | put_tty_queue(c, ldata); | |
1da177e4 | 1221 | } else if (I_INPCK(tty)) |
57c94121 | 1222 | put_tty_queue('\0', ldata); |
1da177e4 | 1223 | else |
57c94121 | 1224 | put_tty_queue(c, ldata); |
1da177e4 LT |
1225 | wake_up_interruptible(&tty->read_wait); |
1226 | } | |
1227 | ||
1228 | /** | |
1229 | * n_tty_receive_char - perform processing | |
1230 | * @tty: terminal device | |
1231 | * @c: character | |
1232 | * | |
1233 | * Process an individual character of input received from the driver. | |
4edf1827 | 1234 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1235 | * driver above. |
6d76bd26 PH |
1236 | * |
1237 | * n_tty_receive_buf()/producer path: | |
1238 | * caller holds non-exclusive termios_rwsem | |
1239 | * publishes canon_head if canonical mode is active | |
1240 | * otherwise, publishes read_head via put_tty_queue() | |
1da177e4 LT |
1241 | */ |
1242 | ||
1243 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1244 | { | |
53c5ee2c | 1245 | struct n_tty_data *ldata = tty->disc_data; |
acc71bba | 1246 | int parmrk; |
1da177e4 | 1247 | |
53c5ee2c | 1248 | if (ldata->raw) { |
57c94121 | 1249 | put_tty_queue(c, ldata); |
1da177e4 LT |
1250 | return; |
1251 | } | |
4edf1827 | 1252 | |
1da177e4 LT |
1253 | if (I_ISTRIP(tty)) |
1254 | c &= 0x7f; | |
1255 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1256 | c = tolower(c); |
1da177e4 | 1257 | |
26df6d13 | 1258 | if (L_EXTPROC(tty)) { |
57c94121 | 1259 | put_tty_queue(c, ldata); |
26df6d13 | 1260 | return; |
1261 | } | |
1262 | ||
54d2a37e | 1263 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1264 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1265 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1266 | start_tty(tty); |
a88a69c9 JP |
1267 | process_echoes(tty); |
1268 | } | |
54d2a37e | 1269 | |
1da177e4 LT |
1270 | if (tty->closing) { |
1271 | if (I_IXON(tty)) { | |
a88a69c9 | 1272 | if (c == START_CHAR(tty)) { |
1da177e4 | 1273 | start_tty(tty); |
a88a69c9 | 1274 | process_echoes(tty); |
300a6204 | 1275 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1276 | stop_tty(tty); |
1277 | } | |
1278 | return; | |
1279 | } | |
1280 | ||
1281 | /* | |
1282 | * If the previous character was LNEXT, or we know that this | |
1283 | * character is not one of the characters that we'll have to | |
1284 | * handle specially, do shortcut processing to speed things | |
1285 | * up. | |
1286 | */ | |
3fe780b3 | 1287 | if (!test_bit(c, ldata->process_char_map) || ldata->lnext) { |
53c5ee2c | 1288 | ldata->lnext = 0; |
acc71bba | 1289 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ce74117a | 1290 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1291 | /* beep if no space */ |
7e94b1d9 JP |
1292 | if (L_ECHO(tty)) |
1293 | process_output('\a', tty); | |
acc71bba JP |
1294 | return; |
1295 | } | |
1296 | if (L_ECHO(tty)) { | |
57c94121 | 1297 | finish_erasing(ldata); |
1da177e4 | 1298 | /* Record the column of first canon char. */ |
ba2e68ac | 1299 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1300 | echo_set_canon_col(ldata); |
1da177e4 | 1301 | echo_char(c, tty); |
17bd7907 | 1302 | commit_echoes(tty); |
1da177e4 | 1303 | } |
acc71bba | 1304 | if (parmrk) |
57c94121 JS |
1305 | put_tty_queue(c, ldata); |
1306 | put_tty_queue(c, ldata); | |
1da177e4 LT |
1307 | return; |
1308 | } | |
4edf1827 | 1309 | |
1da177e4 LT |
1310 | if (I_IXON(tty)) { |
1311 | if (c == START_CHAR(tty)) { | |
1312 | start_tty(tty); | |
17bd7907 | 1313 | commit_echoes(tty); |
1da177e4 LT |
1314 | return; |
1315 | } | |
1316 | if (c == STOP_CHAR(tty)) { | |
1317 | stop_tty(tty); | |
1318 | return; | |
1319 | } | |
1320 | } | |
575537b3 | 1321 | |
1da177e4 LT |
1322 | if (L_ISIG(tty)) { |
1323 | int signal; | |
1324 | signal = SIGINT; | |
1325 | if (c == INTR_CHAR(tty)) | |
1326 | goto send_signal; | |
1327 | signal = SIGQUIT; | |
1328 | if (c == QUIT_CHAR(tty)) | |
1329 | goto send_signal; | |
1330 | signal = SIGTSTP; | |
1331 | if (c == SUSP_CHAR(tty)) { | |
1332 | send_signal: | |
ec5b1157 | 1333 | if (!L_NOFLSH(tty)) { |
6d76bd26 PH |
1334 | /* flushing needs exclusive termios_rwsem */ |
1335 | up_read(&tty->termios_rwsem); | |
ec5b1157 | 1336 | n_tty_flush_buffer(tty); |
f34d7a5b | 1337 | tty_driver_flush_buffer(tty); |
6d76bd26 | 1338 | down_read(&tty->termios_rwsem); |
ec5b1157 | 1339 | } |
a88a69c9 JP |
1340 | if (I_IXON(tty)) |
1341 | start_tty(tty); | |
1342 | if (L_ECHO(tty)) { | |
ec5b1157 | 1343 | echo_char(c, tty); |
17bd7907 | 1344 | commit_echoes(tty); |
a88a69c9 | 1345 | } |
8c985d18 | 1346 | isig(signal, tty); |
1da177e4 LT |
1347 | return; |
1348 | } | |
1349 | } | |
575537b3 JP |
1350 | |
1351 | if (c == '\r') { | |
1352 | if (I_IGNCR(tty)) | |
1353 | return; | |
1354 | if (I_ICRNL(tty)) | |
1355 | c = '\n'; | |
1356 | } else if (c == '\n' && I_INLCR(tty)) | |
1357 | c = '\r'; | |
1358 | ||
53c5ee2c | 1359 | if (ldata->icanon) { |
1da177e4 LT |
1360 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1361 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1362 | eraser(c, tty); | |
17bd7907 | 1363 | commit_echoes(tty); |
1da177e4 LT |
1364 | return; |
1365 | } | |
1366 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1367 | ldata->lnext = 1; |
1da177e4 | 1368 | if (L_ECHO(tty)) { |
57c94121 | 1369 | finish_erasing(ldata); |
1da177e4 | 1370 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1371 | echo_char_raw('^', ldata); |
1372 | echo_char_raw('\b', ldata); | |
17bd7907 | 1373 | commit_echoes(tty); |
1da177e4 LT |
1374 | } |
1375 | } | |
1376 | return; | |
1377 | } | |
1378 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1379 | L_IEXTEN(tty)) { | |
bc5a5e3f | 1380 | size_t tail = ldata->canon_head; |
1da177e4 | 1381 | |
57c94121 | 1382 | finish_erasing(ldata); |
1da177e4 | 1383 | echo_char(c, tty); |
57c94121 | 1384 | echo_char_raw('\n', ldata); |
ba2e68ac | 1385 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1386 | echo_char(read_buf(ldata, tail), tty); |
1387 | tail++; | |
1da177e4 | 1388 | } |
17bd7907 | 1389 | commit_echoes(tty); |
1da177e4 LT |
1390 | return; |
1391 | } | |
1392 | if (c == '\n') { | |
ce74117a | 1393 | if (read_cnt(ldata) >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1394 | if (L_ECHO(tty)) |
1395 | process_output('\a', tty); | |
acc71bba JP |
1396 | return; |
1397 | } | |
1398 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
57c94121 | 1399 | echo_char_raw('\n', ldata); |
17bd7907 | 1400 | commit_echoes(tty); |
1da177e4 LT |
1401 | } |
1402 | goto handle_newline; | |
1403 | } | |
1404 | if (c == EOF_CHAR(tty)) { | |
ce74117a | 1405 | if (read_cnt(ldata) >= N_TTY_BUF_SIZE) |
acc71bba | 1406 | return; |
ba2e68ac | 1407 | if (ldata->canon_head != ldata->read_head) |
4edf1827 | 1408 | set_bit(TTY_PUSH, &tty->flags); |
1da177e4 LT |
1409 | c = __DISABLED_CHAR; |
1410 | goto handle_newline; | |
1411 | } | |
1412 | if ((c == EOL_CHAR(tty)) || | |
1413 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1414 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1415 | ? 1 : 0; | |
ce74117a | 1416 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk)) { |
7e94b1d9 JP |
1417 | if (L_ECHO(tty)) |
1418 | process_output('\a', tty); | |
acc71bba JP |
1419 | return; |
1420 | } | |
1da177e4 LT |
1421 | /* |
1422 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1423 | */ | |
1424 | if (L_ECHO(tty)) { | |
1da177e4 | 1425 | /* Record the column of first canon char. */ |
ba2e68ac | 1426 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1427 | echo_set_canon_col(ldata); |
1da177e4 | 1428 | echo_char(c, tty); |
17bd7907 | 1429 | commit_echoes(tty); |
1da177e4 LT |
1430 | } |
1431 | /* | |
1432 | * XXX does PARMRK doubling happen for | |
1433 | * EOL_CHAR and EOL2_CHAR? | |
1434 | */ | |
acc71bba | 1435 | if (parmrk) |
57c94121 | 1436 | put_tty_queue(c, ldata); |
1da177e4 | 1437 | |
4edf1827 | 1438 | handle_newline: |
bc5a5e3f | 1439 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1440 | put_tty_queue(c, ldata); |
ba2e68ac | 1441 | ldata->canon_head = ldata->read_head; |
1da177e4 LT |
1442 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1443 | if (waitqueue_active(&tty->read_wait)) | |
1444 | wake_up_interruptible(&tty->read_wait); | |
1445 | return; | |
1446 | } | |
1447 | } | |
4edf1827 | 1448 | |
acc71bba | 1449 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ce74117a | 1450 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1451 | /* beep if no space */ |
7e94b1d9 JP |
1452 | if (L_ECHO(tty)) |
1453 | process_output('\a', tty); | |
acc71bba JP |
1454 | return; |
1455 | } | |
1456 | if (L_ECHO(tty)) { | |
57c94121 | 1457 | finish_erasing(ldata); |
1da177e4 | 1458 | if (c == '\n') |
57c94121 | 1459 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1460 | else { |
1461 | /* Record the column of first canon char. */ | |
ba2e68ac | 1462 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1463 | echo_set_canon_col(ldata); |
1da177e4 LT |
1464 | echo_char(c, tty); |
1465 | } | |
17bd7907 | 1466 | commit_echoes(tty); |
1da177e4 LT |
1467 | } |
1468 | ||
acc71bba | 1469 | if (parmrk) |
57c94121 | 1470 | put_tty_queue(c, ldata); |
1da177e4 | 1471 | |
57c94121 | 1472 | put_tty_queue(c, ldata); |
4edf1827 | 1473 | } |
1da177e4 | 1474 | |
1da177e4 LT |
1475 | /** |
1476 | * n_tty_receive_buf - data receive | |
1477 | * @tty: terminal device | |
1478 | * @cp: buffer | |
1479 | * @fp: flag buffer | |
1480 | * @count: characters | |
1481 | * | |
1482 | * Called by the terminal driver when a block of characters has | |
1483 | * been received. This function must be called from soft contexts | |
1484 | * not from interrupt context. The driver is responsible for making | |
1485 | * calls one at a time and in order (or using flush_to_ldisc) | |
6d76bd26 PH |
1486 | * |
1487 | * n_tty_receive_buf()/producer path: | |
1488 | * claims non-exclusive termios_rwsem | |
1489 | * publishes read_head and canon_head | |
1da177e4 | 1490 | */ |
4edf1827 | 1491 | |
24a89d1c PH |
1492 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1493 | char *fp, int count) | |
1da177e4 | 1494 | { |
53c5ee2c | 1495 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1496 | const unsigned char *p; |
1497 | char *f, flags = TTY_NORMAL; | |
1da177e4 | 1498 | char buf[64]; |
1da177e4 | 1499 | |
53c5ee2c | 1500 | if (ldata->real_raw) { |
d1913e39 PH |
1501 | size_t n, head; |
1502 | ||
1503 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1504 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1505 | n = min_t(size_t, count, n); | |
1506 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1507 | ldata->read_head += n; | |
1508 | cp += n; | |
1509 | count -= n; | |
1510 | ||
1511 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1512 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1513 | n = min_t(size_t, count, n); | |
1514 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1515 | ldata->read_head += n; | |
1da177e4 | 1516 | } else { |
d1913e39 PH |
1517 | int i; |
1518 | ||
4edf1827 | 1519 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1520 | if (f) |
1521 | flags = *f++; | |
1522 | switch (flags) { | |
1523 | case TTY_NORMAL: | |
1524 | n_tty_receive_char(tty, *p); | |
1525 | break; | |
1526 | case TTY_BREAK: | |
1527 | n_tty_receive_break(tty); | |
1528 | break; | |
1529 | case TTY_PARITY: | |
1530 | case TTY_FRAME: | |
1531 | n_tty_receive_parity_error(tty, *p); | |
1532 | break; | |
1533 | case TTY_OVERRUN: | |
1534 | n_tty_receive_overrun(tty); | |
1535 | break; | |
1536 | default: | |
4edf1827 | 1537 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1538 | tty_name(tty, buf), flags); |
1539 | break; | |
1540 | } | |
1541 | } | |
cbfd0340 PH |
1542 | |
1543 | flush_echoes(tty); | |
f34d7a5b AC |
1544 | if (tty->ops->flush_chars) |
1545 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1546 | } |
1547 | ||
ce74117a | 1548 | if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) || |
26df6d13 | 1549 | L_EXTPROC(tty)) { |
1da177e4 LT |
1550 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1551 | if (waitqueue_active(&tty->read_wait)) | |
1552 | wake_up_interruptible(&tty->read_wait); | |
1553 | } | |
1554 | ||
6367ca72 | 1555 | n_tty_check_throttle(tty); |
1da177e4 LT |
1556 | } |
1557 | ||
24a89d1c PH |
1558 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1559 | char *fp, int count) | |
1560 | { | |
9356b535 | 1561 | down_read(&tty->termios_rwsem); |
24a89d1c | 1562 | __receive_buf(tty, cp, fp, count); |
9356b535 | 1563 | up_read(&tty->termios_rwsem); |
24a89d1c PH |
1564 | } |
1565 | ||
1566 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1567 | char *fp, int count) | |
1568 | { | |
1569 | struct n_tty_data *ldata = tty->disc_data; | |
1570 | int room; | |
1571 | ||
9356b535 PH |
1572 | down_read(&tty->termios_rwsem); |
1573 | ||
24a89d1c PH |
1574 | tty->receive_room = room = receive_room(tty); |
1575 | if (!room) | |
1576 | ldata->no_room = 1; | |
1577 | count = min(count, room); | |
1578 | if (count) | |
1579 | __receive_buf(tty, cp, fp, count); | |
1580 | ||
9356b535 PH |
1581 | up_read(&tty->termios_rwsem); |
1582 | ||
24a89d1c PH |
1583 | return count; |
1584 | } | |
1585 | ||
1da177e4 LT |
1586 | int is_ignored(int sig) |
1587 | { | |
1588 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1589 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1590 | } |
1591 | ||
1592 | /** | |
1593 | * n_tty_set_termios - termios data changed | |
1594 | * @tty: terminal | |
1595 | * @old: previous data | |
1596 | * | |
1597 | * Called by the tty layer when the user changes termios flags so | |
1598 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1599 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1600 | * guaranteed that this function will not be re-entered or in progress |
1601 | * when the ldisc is closed. | |
17b82060 | 1602 | * |
6a1c0680 | 1603 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1604 | */ |
4edf1827 AC |
1605 | |
1606 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1607 | { |
53c5ee2c | 1608 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1609 | int canon_change = 1; |
47afa7a5 AC |
1610 | |
1611 | if (old) | |
adc8d746 | 1612 | canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON; |
47afa7a5 | 1613 | if (canon_change) { |
3fe780b3 | 1614 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
ba2e68ac | 1615 | ldata->canon_head = ldata->read_tail; |
53c5ee2c | 1616 | ldata->erasing = 0; |
6f9b028a | 1617 | ldata->lnext = 0; |
47afa7a5 AC |
1618 | } |
1619 | ||
ce74117a | 1620 | if (canon_change && !L_ICANON(tty) && read_cnt(ldata)) |
47afa7a5 | 1621 | wake_up_interruptible(&tty->read_wait); |
4edf1827 | 1622 | |
53c5ee2c | 1623 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1624 | |
1da177e4 LT |
1625 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1626 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1627 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1628 | I_PARMRK(tty)) { | |
3fe780b3 | 1629 | bitmap_zero(ldata->process_char_map, 256); |
1da177e4 LT |
1630 | |
1631 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
3fe780b3 | 1632 | set_bit('\r', ldata->process_char_map); |
1da177e4 | 1633 | if (I_INLCR(tty)) |
3fe780b3 | 1634 | set_bit('\n', ldata->process_char_map); |
1da177e4 LT |
1635 | |
1636 | if (L_ICANON(tty)) { | |
3fe780b3 JS |
1637 | set_bit(ERASE_CHAR(tty), ldata->process_char_map); |
1638 | set_bit(KILL_CHAR(tty), ldata->process_char_map); | |
1639 | set_bit(EOF_CHAR(tty), ldata->process_char_map); | |
1640 | set_bit('\n', ldata->process_char_map); | |
1641 | set_bit(EOL_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1642 | if (L_IEXTEN(tty)) { |
1643 | set_bit(WERASE_CHAR(tty), | |
3fe780b3 | 1644 | ldata->process_char_map); |
1da177e4 | 1645 | set_bit(LNEXT_CHAR(tty), |
3fe780b3 | 1646 | ldata->process_char_map); |
1da177e4 | 1647 | set_bit(EOL2_CHAR(tty), |
3fe780b3 | 1648 | ldata->process_char_map); |
1da177e4 LT |
1649 | if (L_ECHO(tty)) |
1650 | set_bit(REPRINT_CHAR(tty), | |
3fe780b3 | 1651 | ldata->process_char_map); |
1da177e4 LT |
1652 | } |
1653 | } | |
1654 | if (I_IXON(tty)) { | |
3fe780b3 JS |
1655 | set_bit(START_CHAR(tty), ldata->process_char_map); |
1656 | set_bit(STOP_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1657 | } |
1658 | if (L_ISIG(tty)) { | |
3fe780b3 JS |
1659 | set_bit(INTR_CHAR(tty), ldata->process_char_map); |
1660 | set_bit(QUIT_CHAR(tty), ldata->process_char_map); | |
1661 | set_bit(SUSP_CHAR(tty), ldata->process_char_map); | |
1da177e4 | 1662 | } |
3fe780b3 | 1663 | clear_bit(__DISABLED_CHAR, ldata->process_char_map); |
53c5ee2c JS |
1664 | ldata->raw = 0; |
1665 | ldata->real_raw = 0; | |
1da177e4 | 1666 | } else { |
53c5ee2c | 1667 | ldata->raw = 1; |
1da177e4 LT |
1668 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1669 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1670 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1671 | ldata->real_raw = 1; |
1da177e4 | 1672 | else |
53c5ee2c | 1673 | ldata->real_raw = 0; |
1da177e4 | 1674 | } |
55db4c64 | 1675 | n_tty_set_room(tty); |
dab73b4e WY |
1676 | /* |
1677 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1678 | * been stopped by STOP_CHAR(tty) before it. | |
1679 | */ | |
1680 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { | |
1681 | start_tty(tty); | |
1682 | } | |
1683 | ||
f34d7a5b AC |
1684 | /* The termios change make the tty ready for I/O */ |
1685 | wake_up_interruptible(&tty->write_wait); | |
1686 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1687 | } |
1688 | ||
1689 | /** | |
1690 | * n_tty_close - close the ldisc for this tty | |
1691 | * @tty: device | |
1692 | * | |
4edf1827 AC |
1693 | * Called from the terminal layer when this line discipline is |
1694 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1695 | * discipline change. The function will not be called while other |
1696 | * ldisc methods are in progress. | |
1697 | */ | |
4edf1827 | 1698 | |
1da177e4 LT |
1699 | static void n_tty_close(struct tty_struct *tty) |
1700 | { | |
70ece7a7 JS |
1701 | struct n_tty_data *ldata = tty->disc_data; |
1702 | ||
79901317 PH |
1703 | if (tty->link) |
1704 | n_tty_packet_mode_flush(tty); | |
1705 | ||
ba2e68ac JS |
1706 | kfree(ldata->read_buf); |
1707 | kfree(ldata->echo_buf); | |
70ece7a7 | 1708 | kfree(ldata); |
70ece7a7 | 1709 | tty->disc_data = NULL; |
1da177e4 LT |
1710 | } |
1711 | ||
1712 | /** | |
1713 | * n_tty_open - open an ldisc | |
1714 | * @tty: terminal to open | |
1715 | * | |
4edf1827 | 1716 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1717 | * terminal device. Can sleep. Called serialized so that no |
1718 | * other events will occur in parallel. No further open will occur | |
1719 | * until a close. | |
1720 | */ | |
1721 | ||
1722 | static int n_tty_open(struct tty_struct *tty) | |
1723 | { | |
70ece7a7 JS |
1724 | struct n_tty_data *ldata; |
1725 | ||
1726 | ldata = kzalloc(sizeof(*ldata), GFP_KERNEL); | |
1727 | if (!ldata) | |
1728 | goto err; | |
1729 | ||
53c5ee2c | 1730 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1731 | mutex_init(&ldata->atomic_read_lock); |
1732 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1733 | |
a88a69c9 | 1734 | /* These are ugly. Currently a malloc failure here can panic */ |
ba2e68ac JS |
1735 | ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1736 | ldata->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); | |
1737 | if (!ldata->read_buf || !ldata->echo_buf) | |
b91939f5 | 1738 | goto err_free_bufs; |
0b4068a1 | 1739 | |
70ece7a7 | 1740 | tty->disc_data = ldata; |
b66f4fa5 | 1741 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1742 | ldata->column = 0; |
f6c8dbe6 | 1743 | ldata->minimum_to_wake = 1; |
1da177e4 | 1744 | tty->closing = 0; |
b66f4fa5 PH |
1745 | /* indicate buffer work may resume */ |
1746 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1747 | n_tty_set_termios(tty, NULL); | |
1748 | tty_unthrottle(tty); | |
70ece7a7 | 1749 | |
1da177e4 | 1750 | return 0; |
b91939f5 | 1751 | err_free_bufs: |
ba2e68ac JS |
1752 | kfree(ldata->read_buf); |
1753 | kfree(ldata->echo_buf); | |
70ece7a7 JS |
1754 | kfree(ldata); |
1755 | err: | |
b91939f5 | 1756 | return -ENOMEM; |
1da177e4 LT |
1757 | } |
1758 | ||
1759 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1760 | { | |
53c5ee2c JS |
1761 | struct n_tty_data *ldata = tty->disc_data; |
1762 | ||
53c5ee2c | 1763 | if (ldata->icanon && !L_EXTPROC(tty)) { |
a73d3d69 | 1764 | if (ldata->canon_head != ldata->read_tail) |
1da177e4 | 1765 | return 1; |
ce74117a | 1766 | } else if (read_cnt(ldata) >= (amt ? amt : 1)) |
1da177e4 LT |
1767 | return 1; |
1768 | ||
1769 | return 0; | |
1770 | } | |
1771 | ||
1772 | /** | |
bbd20759 | 1773 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1774 | * @tty: terminal device |
1775 | * @b: user data | |
1776 | * @nr: size of data | |
1777 | * | |
11a96d18 | 1778 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1779 | * ICANON is off; it copies characters straight from the tty queue to |
1780 | * user space directly. It can be profitably called twice; once to | |
1781 | * drain the space from the tail pointer to the (physical) end of the | |
1782 | * buffer, and once to drain the space from the (physical) beginning of | |
1783 | * the buffer to head pointer. | |
1784 | * | |
bddc7152 | 1785 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1786 | * |
6d76bd26 PH |
1787 | * n_tty_read()/consumer path: |
1788 | * caller holds non-exclusive termios_rwsem | |
1789 | * read_tail published | |
1da177e4 | 1790 | */ |
4edf1827 | 1791 | |
33f0f88f | 1792 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1793 | unsigned char __user **b, |
1794 | size_t *nr) | |
1795 | ||
1796 | { | |
53c5ee2c | 1797 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1798 | int retval; |
1799 | size_t n; | |
3fa10cc8 | 1800 | bool is_eof; |
bc5a5e3f | 1801 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1802 | |
1803 | retval = 0; | |
bc5a5e3f | 1804 | n = min(read_cnt(ldata), N_TTY_BUF_SIZE - tail); |
1da177e4 | 1805 | n = min(*nr, n); |
1da177e4 | 1806 | if (n) { |
bc5a5e3f | 1807 | retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
1da177e4 | 1808 | n -= retval; |
bc5a5e3f PH |
1809 | is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); |
1810 | tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, | |
53c5ee2c | 1811 | ldata->icanon); |
bc5a5e3f | 1812 | ldata->read_tail += n; |
26df6d13 | 1813 | /* Turn single EOF into zero-length read */ |
ce74117a | 1814 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !read_cnt(ldata)) |
3fa10cc8 | 1815 | n = 0; |
1da177e4 LT |
1816 | *b += n; |
1817 | *nr -= n; | |
1818 | } | |
1819 | return retval; | |
1820 | } | |
1821 | ||
88bb0de3 | 1822 | /** |
32f13521 | 1823 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1824 | * @tty: terminal device |
1825 | * @b: user data | |
1826 | * @nr: size of data | |
1827 | * | |
1828 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1829 | * it copies one line of input up to and including the line-delimiting |
1830 | * character into the user-space buffer. | |
88bb0de3 PH |
1831 | * |
1832 | * Called under the atomic_read_lock mutex | |
6d76bd26 PH |
1833 | * |
1834 | * n_tty_read()/consumer path: | |
1835 | * caller holds non-exclusive termios_rwsem | |
1836 | * read_tail published | |
88bb0de3 PH |
1837 | */ |
1838 | ||
32f13521 PH |
1839 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
1840 | unsigned char __user **b, | |
1841 | size_t *nr) | |
88bb0de3 PH |
1842 | { |
1843 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 1844 | size_t n, size, more, c; |
bc5a5e3f PH |
1845 | size_t eol; |
1846 | size_t tail; | |
1847 | int ret, found = 0; | |
88bb0de3 PH |
1848 | |
1849 | /* N.B. avoid overrun if nr == 0 */ | |
ce74117a | 1850 | n = min(*nr, read_cnt(ldata)); |
6d76bd26 | 1851 | if (!n) |
32f13521 | 1852 | return 0; |
88bb0de3 | 1853 | |
bc5a5e3f | 1854 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
1855 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
1856 | ||
bc5a5e3f | 1857 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
1858 | __func__, *nr, tail, n, size); |
1859 | ||
1860 | eol = find_next_bit(ldata->read_flags, size, tail); | |
1861 | more = n - (size - tail); | |
1862 | if (eol == N_TTY_BUF_SIZE && more) { | |
1863 | /* scan wrapped without finding set bit */ | |
1864 | eol = find_next_bit(ldata->read_flags, more, 0); | |
1865 | if (eol != more) | |
1866 | found = 1; | |
1867 | } else if (eol != size) | |
1868 | found = 1; | |
1869 | ||
1870 | size = N_TTY_BUF_SIZE - tail; | |
1871 | n = (found + eol + size) & (N_TTY_BUF_SIZE - 1); | |
1872 | c = n; | |
1873 | ||
bc5a5e3f | 1874 | if (found && read_buf(ldata, eol) == __DISABLED_CHAR) |
32f13521 PH |
1875 | n--; |
1876 | ||
bc5a5e3f | 1877 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", |
32f13521 PH |
1878 | __func__, eol, found, n, c, size, more); |
1879 | ||
32f13521 | 1880 | if (n > size) { |
bc5a5e3f | 1881 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), size); |
32f13521 PH |
1882 | if (ret) |
1883 | return -EFAULT; | |
1884 | ret = copy_to_user(*b + size, ldata->read_buf, n - size); | |
1885 | } else | |
bc5a5e3f | 1886 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
32f13521 PH |
1887 | |
1888 | if (ret) | |
1889 | return -EFAULT; | |
1890 | *b += n; | |
1891 | *nr -= n; | |
1892 | ||
a73d3d69 | 1893 | if (found) |
6d76bd26 PH |
1894 | clear_bit(eol, ldata->read_flags); |
1895 | smp_mb__after_clear_bit(); | |
1896 | ldata->read_tail += c; | |
88bb0de3 | 1897 | |
32f13521 PH |
1898 | if (found) |
1899 | tty_audit_push(tty); | |
88bb0de3 PH |
1900 | return 0; |
1901 | } | |
1902 | ||
cc4191dc | 1903 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1904 | size_t, loff_t *); |
1da177e4 LT |
1905 | |
1906 | /** | |
1907 | * job_control - check job control | |
1908 | * @tty: tty | |
1909 | * @file: file handle | |
1910 | * | |
1911 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1912 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1913 | * error code if action should be taken. |
04f378b1 | 1914 | * |
01a5e440 PH |
1915 | * Locking: redirected write test is safe |
1916 | * current->signal->tty check is safe | |
1917 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 1918 | */ |
4edf1827 | 1919 | |
1da177e4 LT |
1920 | static int job_control(struct tty_struct *tty, struct file *file) |
1921 | { | |
1922 | /* Job control check -- must be done at start and after | |
1923 | every sleep (POSIX.1 7.1.1.4). */ | |
1924 | /* NOTE: not yet done after every sleep pending a thorough | |
1925 | check of the logic of this change. -- jlc */ | |
1926 | /* don't stop on /dev/console */ | |
01a5e440 PH |
1927 | if (file->f_op->write == redirected_tty_write || |
1928 | current->signal->tty != tty) | |
1929 | return 0; | |
1930 | ||
1931 | spin_lock_irq(&tty->ctrl_lock); | |
1932 | if (!tty->pgrp) | |
1933 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
1934 | else if (task_pgrp(current) != tty->pgrp) { | |
1935 | spin_unlock_irq(&tty->ctrl_lock); | |
1936 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
1937 | return -EIO; | |
1938 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
1939 | set_thread_flag(TIF_SIGPENDING); | |
1940 | return -ERESTARTSYS; | |
1da177e4 | 1941 | } |
01a5e440 | 1942 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
1943 | return 0; |
1944 | } | |
4edf1827 | 1945 | |
1da177e4 LT |
1946 | |
1947 | /** | |
11a96d18 | 1948 | * n_tty_read - read function for tty |
1da177e4 LT |
1949 | * @tty: tty device |
1950 | * @file: file object | |
1951 | * @buf: userspace buffer pointer | |
1952 | * @nr: size of I/O | |
1953 | * | |
1954 | * Perform reads for the line discipline. We are guaranteed that the | |
1955 | * line discipline will not be closed under us but we may get multiple | |
1956 | * parallel readers and must handle this ourselves. We may also get | |
1957 | * a hangup. Always called in user context, may sleep. | |
1958 | * | |
1959 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
1960 | * |
1961 | * n_tty_read()/consumer path: | |
1962 | * claims non-exclusive termios_rwsem | |
1963 | * publishes read_tail | |
1da177e4 | 1964 | */ |
4edf1827 | 1965 | |
11a96d18 | 1966 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1967 | unsigned char __user *buf, size_t nr) |
1968 | { | |
53c5ee2c | 1969 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1970 | unsigned char __user *b = buf; |
1971 | DECLARE_WAITQUEUE(wait, current); | |
1972 | int c; | |
1973 | int minimum, time; | |
1974 | ssize_t retval = 0; | |
1975 | ssize_t size; | |
1976 | long timeout; | |
1977 | unsigned long flags; | |
04f378b1 | 1978 | int packet; |
1da177e4 LT |
1979 | |
1980 | do_it_again: | |
1da177e4 | 1981 | c = job_control(tty, file); |
4edf1827 | 1982 | if (c < 0) |
1da177e4 | 1983 | return c; |
4edf1827 | 1984 | |
9356b535 PH |
1985 | down_read(&tty->termios_rwsem); |
1986 | ||
1da177e4 LT |
1987 | minimum = time = 0; |
1988 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 1989 | if (!ldata->icanon) { |
1da177e4 LT |
1990 | minimum = MIN_CHAR(tty); |
1991 | if (minimum) { | |
a6e54319 | 1992 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 1993 | if (time) |
f6c8dbe6 | 1994 | ldata->minimum_to_wake = 1; |
1da177e4 | 1995 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
1996 | (ldata->minimum_to_wake > minimum)) |
1997 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 1998 | } else { |
a6e54319 | 1999 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2000 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2001 | } |
2002 | } | |
2003 | ||
2004 | /* | |
2005 | * Internal serialization of reads. | |
2006 | */ | |
2007 | if (file->f_flags & O_NONBLOCK) { | |
9356b535 PH |
2008 | if (!mutex_trylock(&ldata->atomic_read_lock)) { |
2009 | up_read(&tty->termios_rwsem); | |
1da177e4 | 2010 | return -EAGAIN; |
9356b535 | 2011 | } |
4edf1827 | 2012 | } else { |
9356b535 PH |
2013 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) { |
2014 | up_read(&tty->termios_rwsem); | |
1da177e4 | 2015 | return -ERESTARTSYS; |
9356b535 | 2016 | } |
1da177e4 | 2017 | } |
04f378b1 | 2018 | packet = tty->packet; |
1da177e4 LT |
2019 | |
2020 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2021 | while (nr) { |
2022 | /* First test for status change. */ | |
04f378b1 | 2023 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2024 | unsigned char cs; |
2025 | if (b != buf) | |
2026 | break; | |
04f378b1 | 2027 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
2028 | cs = tty->link->ctrl_status; |
2029 | tty->link->ctrl_status = 0; | |
04f378b1 | 2030 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 2031 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2032 | retval = -EFAULT; |
2033 | b--; | |
2034 | break; | |
2035 | } | |
2036 | nr--; | |
2037 | break; | |
2038 | } | |
2039 | /* This statement must be first before checking for input | |
2040 | so that any interrupt will set the state back to | |
2041 | TASK_RUNNING. */ | |
2042 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 2043 | |
f6c8dbe6 | 2044 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2045 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2046 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2047 | |
1da177e4 LT |
2048 | if (!input_available_p(tty, 0)) { |
2049 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
2050 | retval = -EIO; | |
2051 | break; | |
2052 | } | |
2053 | if (tty_hung_up_p(file)) | |
2054 | break; | |
2055 | if (!timeout) | |
2056 | break; | |
2057 | if (file->f_flags & O_NONBLOCK) { | |
2058 | retval = -EAGAIN; | |
2059 | break; | |
2060 | } | |
2061 | if (signal_pending(current)) { | |
2062 | retval = -ERESTARTSYS; | |
2063 | break; | |
2064 | } | |
55db4c64 | 2065 | n_tty_set_room(tty); |
9356b535 PH |
2066 | up_read(&tty->termios_rwsem); |
2067 | ||
1da177e4 | 2068 | timeout = schedule_timeout(timeout); |
9356b535 PH |
2069 | |
2070 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2071 | continue; |
2072 | } | |
2073 | __set_current_state(TASK_RUNNING); | |
2074 | ||
2075 | /* Deal with packet mode. */ | |
04f378b1 | 2076 | if (packet && b == buf) { |
522ed776 | 2077 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
2078 | retval = -EFAULT; |
2079 | b--; | |
2080 | break; | |
2081 | } | |
2082 | nr--; | |
2083 | } | |
2084 | ||
53c5ee2c | 2085 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2086 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
1da177e4 LT |
2087 | if (retval) |
2088 | break; | |
2089 | } else { | |
2090 | int uncopied; | |
04f378b1 AC |
2091 | /* The copy function takes the read lock and handles |
2092 | locking internally for this case */ | |
1da177e4 LT |
2093 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2094 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2095 | if (uncopied) { | |
2096 | retval = -EFAULT; | |
2097 | break; | |
2098 | } | |
2099 | } | |
2100 | ||
6367ca72 | 2101 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2102 | |
2103 | if (b - buf >= minimum) | |
2104 | break; | |
2105 | if (time) | |
2106 | timeout = time; | |
2107 | } | |
bddc7152 | 2108 | mutex_unlock(&ldata->atomic_read_lock); |
1da177e4 LT |
2109 | remove_wait_queue(&tty->read_wait, &wait); |
2110 | ||
2111 | if (!waitqueue_active(&tty->read_wait)) | |
f6c8dbe6 | 2112 | ldata->minimum_to_wake = minimum; |
1da177e4 LT |
2113 | |
2114 | __set_current_state(TASK_RUNNING); | |
2115 | size = b - buf; | |
2116 | if (size) { | |
2117 | retval = size; | |
2118 | if (nr) | |
4edf1827 | 2119 | clear_bit(TTY_PUSH, &tty->flags); |
9356b535 PH |
2120 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) { |
2121 | up_read(&tty->termios_rwsem); | |
bbd20759 | 2122 | goto do_it_again; |
9356b535 | 2123 | } |
1da177e4 | 2124 | |
55db4c64 | 2125 | n_tty_set_room(tty); |
9356b535 | 2126 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2127 | return retval; |
2128 | } | |
2129 | ||
2130 | /** | |
11a96d18 | 2131 | * n_tty_write - write function for tty |
1da177e4 LT |
2132 | * @tty: tty device |
2133 | * @file: file object | |
2134 | * @buf: userspace buffer pointer | |
2135 | * @nr: size of I/O | |
2136 | * | |
a88a69c9 | 2137 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2138 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2139 | * and other such events. Since the receive code will echo characters, |
2140 | * thus calling driver write methods, the output_lock is used in | |
2141 | * the output processing functions called here as well as in the | |
2142 | * echo processing function to protect the column state and space | |
2143 | * left in the buffer. | |
1da177e4 LT |
2144 | * |
2145 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2146 | * |
2147 | * Locking: output_lock to protect column state and space left | |
2148 | * (note that the process_output*() functions take this | |
2149 | * lock themselves) | |
1da177e4 | 2150 | */ |
4edf1827 | 2151 | |
11a96d18 | 2152 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2153 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2154 | { |
2155 | const unsigned char *b = buf; | |
2156 | DECLARE_WAITQUEUE(wait, current); | |
2157 | int c; | |
2158 | ssize_t retval = 0; | |
2159 | ||
2160 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2161 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2162 | retval = tty_check_change(tty); | |
2163 | if (retval) | |
2164 | return retval; | |
2165 | } | |
2166 | ||
9356b535 PH |
2167 | down_read(&tty->termios_rwsem); |
2168 | ||
a88a69c9 JP |
2169 | /* Write out any echoed characters that are still pending */ |
2170 | process_echoes(tty); | |
300a6204 | 2171 | |
1da177e4 LT |
2172 | add_wait_queue(&tty->write_wait, &wait); |
2173 | while (1) { | |
2174 | set_current_state(TASK_INTERRUPTIBLE); | |
2175 | if (signal_pending(current)) { | |
2176 | retval = -ERESTARTSYS; | |
2177 | break; | |
2178 | } | |
2179 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2180 | retval = -EIO; | |
2181 | break; | |
2182 | } | |
582f5590 | 2183 | if (O_OPOST(tty)) { |
1da177e4 | 2184 | while (nr > 0) { |
a88a69c9 | 2185 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2186 | if (num < 0) { |
2187 | if (num == -EAGAIN) | |
2188 | break; | |
2189 | retval = num; | |
2190 | goto break_out; | |
2191 | } | |
2192 | b += num; | |
2193 | nr -= num; | |
2194 | if (nr == 0) | |
2195 | break; | |
2196 | c = *b; | |
a88a69c9 | 2197 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2198 | break; |
2199 | b++; nr--; | |
2200 | } | |
f34d7a5b AC |
2201 | if (tty->ops->flush_chars) |
2202 | tty->ops->flush_chars(tty); | |
1da177e4 | 2203 | } else { |
d6afe27b | 2204 | while (nr > 0) { |
f34d7a5b | 2205 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
2206 | if (c < 0) { |
2207 | retval = c; | |
2208 | goto break_out; | |
2209 | } | |
2210 | if (!c) | |
2211 | break; | |
2212 | b += c; | |
2213 | nr -= c; | |
1da177e4 | 2214 | } |
1da177e4 LT |
2215 | } |
2216 | if (!nr) | |
2217 | break; | |
2218 | if (file->f_flags & O_NONBLOCK) { | |
2219 | retval = -EAGAIN; | |
2220 | break; | |
2221 | } | |
9356b535 PH |
2222 | up_read(&tty->termios_rwsem); |
2223 | ||
1da177e4 | 2224 | schedule(); |
9356b535 PH |
2225 | |
2226 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2227 | } |
2228 | break_out: | |
2229 | __set_current_state(TASK_RUNNING); | |
2230 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2231 | if (b - buf != nr && tty->fasync) |
2232 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2233 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2234 | return (b - buf) ? b - buf : retval; |
2235 | } | |
2236 | ||
2237 | /** | |
11a96d18 | 2238 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2239 | * @tty: terminal device |
2240 | * @file: file accessing it | |
2241 | * @wait: poll table | |
2242 | * | |
2243 | * Called when the line discipline is asked to poll() for data or | |
2244 | * for special events. This code is not serialized with respect to | |
2245 | * other events save open/close. | |
2246 | * | |
2247 | * This code must be sure never to sleep through a hangup. | |
2248 | * Called without the kernel lock held - fine | |
1da177e4 | 2249 | */ |
4edf1827 | 2250 | |
11a96d18 | 2251 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2252 | poll_table *wait) |
1da177e4 | 2253 | { |
f6c8dbe6 | 2254 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2255 | unsigned int mask = 0; |
2256 | ||
2257 | poll_wait(file, &tty->read_wait, wait); | |
2258 | poll_wait(file, &tty->write_wait, wait); | |
2259 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2260 | mask |= POLLIN | POLLRDNORM; | |
2261 | if (tty->packet && tty->link->ctrl_status) | |
2262 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2263 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2264 | mask |= POLLHUP; | |
2265 | if (tty_hung_up_p(file)) | |
2266 | mask |= POLLHUP; | |
2267 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2268 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2269 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2270 | else |
f6c8dbe6 | 2271 | ldata->minimum_to_wake = 1; |
1da177e4 | 2272 | } |
f34d7a5b AC |
2273 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2274 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2275 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2276 | mask |= POLLOUT | POLLWRNORM; |
2277 | return mask; | |
2278 | } | |
2279 | ||
57c94121 | 2280 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2281 | { |
bc5a5e3f | 2282 | size_t nr, head, tail; |
47afa7a5 | 2283 | |
a73d3d69 | 2284 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2285 | return 0; |
ba2e68ac JS |
2286 | head = ldata->canon_head; |
2287 | tail = ldata->read_tail; | |
bc5a5e3f | 2288 | nr = head - tail; |
47afa7a5 AC |
2289 | /* Skip EOF-chars.. */ |
2290 | while (head != tail) { | |
bc5a5e3f PH |
2291 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2292 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2293 | nr--; |
bc5a5e3f | 2294 | tail++; |
47afa7a5 AC |
2295 | } |
2296 | return nr; | |
2297 | } | |
2298 | ||
2299 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2300 | unsigned int cmd, unsigned long arg) | |
2301 | { | |
ba2e68ac | 2302 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2303 | int retval; |
2304 | ||
2305 | switch (cmd) { | |
2306 | case TIOCOUTQ: | |
2307 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2308 | case TIOCINQ: | |
6d76bd26 | 2309 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2310 | if (L_ICANON(tty)) |
57c94121 | 2311 | retval = inq_canon(ldata); |
6d76bd26 PH |
2312 | else |
2313 | retval = read_cnt(ldata); | |
2314 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2315 | return put_user(retval, (unsigned int __user *) arg); |
2316 | default: | |
2317 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2318 | } | |
2319 | } | |
2320 | ||
f6c8dbe6 PH |
2321 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2322 | { | |
2323 | struct n_tty_data *ldata = tty->disc_data; | |
2324 | ||
2325 | if (!waitqueue_active(&tty->read_wait)) { | |
2326 | if (on) | |
2327 | ldata->minimum_to_wake = 1; | |
2328 | else if (!tty->fasync) | |
2329 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2330 | } | |
2331 | } | |
2332 | ||
a352def2 | 2333 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2334 | .magic = TTY_LDISC_MAGIC, |
2335 | .name = "n_tty", | |
2336 | .open = n_tty_open, | |
2337 | .close = n_tty_close, | |
2338 | .flush_buffer = n_tty_flush_buffer, | |
2339 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2340 | .read = n_tty_read, |
2341 | .write = n_tty_write, | |
e10cc1df PF |
2342 | .ioctl = n_tty_ioctl, |
2343 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2344 | .poll = n_tty_poll, |
e10cc1df | 2345 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2346 | .write_wakeup = n_tty_write_wakeup, |
2347 | .fasync = n_tty_fasync, | |
24a89d1c | 2348 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2349 | }; |
572b9adb RG |
2350 | |
2351 | /** | |
2352 | * n_tty_inherit_ops - inherit N_TTY methods | |
2353 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2354 | * | |
593fb1ae | 2355 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2356 | * methods. |
2357 | */ | |
2358 | ||
2359 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2360 | { | |
2361 | *ops = tty_ldisc_N_TTY; | |
2362 | ops->owner = NULL; | |
2363 | ops->refcount = ops->flags = 0; | |
2364 | } | |
2365 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |