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Commit | Line | Data |
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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> |
86e35aea | 53 | #include <linux/vmalloc.h> |
1da177e4 | 54 | |
1da177e4 LT |
55 | |
56 | /* number of characters left in xmit buffer before select has we have room */ | |
57 | #define WAKEUP_CHARS 256 | |
58 | ||
59 | /* | |
60 | * This defines the low- and high-watermarks for throttling and | |
61 | * unthrottling the TTY driver. These watermarks are used for | |
62 | * controlling the space in the read buffer. | |
63 | */ | |
64 | #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ | |
bbd20759 | 65 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
1da177e4 | 66 | |
a88a69c9 JP |
67 | /* |
68 | * Special byte codes used in the echo buffer to represent operations | |
69 | * or special handling of characters. Bytes in the echo buffer that | |
70 | * are not part of such special blocks are treated as normal character | |
71 | * codes. | |
72 | */ | |
73 | #define ECHO_OP_START 0xff | |
74 | #define ECHO_OP_MOVE_BACK_COL 0x80 | |
75 | #define ECHO_OP_SET_CANON_COL 0x81 | |
76 | #define ECHO_OP_ERASE_TAB 0x82 | |
77 | ||
cbfd0340 PH |
78 | #define ECHO_COMMIT_WATERMARK 256 |
79 | #define ECHO_BLOCK 256 | |
80 | #define ECHO_DISCARD_WATERMARK N_TTY_BUF_SIZE - (ECHO_BLOCK + 32) | |
81 | ||
82 | ||
32f13521 PH |
83 | #undef N_TTY_TRACE |
84 | #ifdef N_TTY_TRACE | |
85 | # define n_tty_trace(f, args...) trace_printk(f, ##args) | |
86 | #else | |
87 | # define n_tty_trace(f, args...) | |
88 | #endif | |
89 | ||
70ece7a7 | 90 | struct n_tty_data { |
fb7aa03d PH |
91 | /* producer-published */ |
92 | size_t read_head; | |
93 | size_t canon_head; | |
9dfd16dd PH |
94 | size_t echo_head; |
95 | size_t echo_commit; | |
1bb9d562 | 96 | DECLARE_BITMAP(char_map, 256); |
fb7aa03d PH |
97 | |
98 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c JS |
99 | unsigned long overrun_time; |
100 | int num_overrun; | |
101 | ||
24a89d1c PH |
102 | /* non-atomic */ |
103 | bool no_room; | |
104 | ||
fb7aa03d | 105 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c | 106 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
3fe780b3 | 107 | |
fb7aa03d | 108 | /* shared by producer and consumer */ |
20bafb3d | 109 | char read_buf[N_TTY_BUF_SIZE]; |
3fe780b3 | 110 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
20bafb3d | 111 | unsigned char echo_buf[N_TTY_BUF_SIZE]; |
ba2e68ac | 112 | |
f6c8dbe6 | 113 | int minimum_to_wake; |
ba2e68ac | 114 | |
fb7aa03d PH |
115 | /* consumer-published */ |
116 | size_t read_tail; | |
40d5e090 | 117 | size_t line_start; |
fb7aa03d | 118 | |
fb7aa03d PH |
119 | /* protected by output lock */ |
120 | unsigned int column; | |
ba2e68ac | 121 | unsigned int canon_column; |
9dfd16dd | 122 | size_t echo_tail; |
bddc7152 JS |
123 | |
124 | struct mutex atomic_read_lock; | |
125 | struct mutex output_lock; | |
70ece7a7 JS |
126 | }; |
127 | ||
ce74117a PH |
128 | static inline size_t read_cnt(struct n_tty_data *ldata) |
129 | { | |
a2f73be8 | 130 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
131 | } |
132 | ||
bc5a5e3f PH |
133 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
134 | { | |
135 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
136 | } | |
137 | ||
138 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
139 | { | |
140 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
141 | } | |
142 | ||
addaebcc PH |
143 | static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) |
144 | { | |
145 | return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
146 | } | |
147 | ||
148 | static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) | |
149 | { | |
150 | return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
151 | } | |
152 | ||
522ed776 MT |
153 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
154 | unsigned char __user *ptr) | |
155 | { | |
53c5ee2c JS |
156 | struct n_tty_data *ldata = tty->disc_data; |
157 | ||
158 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
159 | return put_user(x, ptr); |
160 | } | |
161 | ||
24a89d1c | 162 | static int receive_room(struct tty_struct *tty) |
55db4c64 | 163 | { |
53c5ee2c | 164 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 165 | int left; |
55db4c64 | 166 | |
090abf7b JA |
167 | if (I_PARMRK(tty)) { |
168 | /* Multiply read_cnt by 3, since each byte might take up to | |
169 | * three times as many spaces when PARMRK is set (depending on | |
170 | * its flags, e.g. parity error). */ | |
ce74117a | 171 | left = N_TTY_BUF_SIZE - read_cnt(ldata) * 3 - 1; |
090abf7b | 172 | } else |
ce74117a | 173 | left = N_TTY_BUF_SIZE - read_cnt(ldata) - 1; |
090abf7b | 174 | |
55db4c64 LT |
175 | /* |
176 | * If we are doing input canonicalization, and there are no | |
177 | * pending newlines, let characters through without limit, so | |
178 | * that erase characters will be handled. Other excess | |
179 | * characters will be beeped. | |
180 | */ | |
181 | if (left <= 0) | |
a73d3d69 | 182 | left = ldata->icanon && ldata->canon_head == ldata->read_tail; |
55db4c64 | 183 | |
24a89d1c | 184 | return left; |
7879a9f9 PH |
185 | } |
186 | ||
24a89d1c PH |
187 | /** |
188 | * n_tty_set_room - receive space | |
189 | * @tty: terminal | |
190 | * | |
191 | * Re-schedules the flip buffer work if space just became available. | |
192 | * | |
6d76bd26 PH |
193 | * Caller holds exclusive termios_rwsem |
194 | * or | |
195 | * n_tty_read()/consumer path: | |
196 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
197 | */ |
198 | ||
7879a9f9 PH |
199 | static void n_tty_set_room(struct tty_struct *tty) |
200 | { | |
24a89d1c PH |
201 | struct n_tty_data *ldata = tty->disc_data; |
202 | ||
55db4c64 | 203 | /* Did this open up the receive buffer? We may need to flip */ |
24a89d1c PH |
204 | if (unlikely(ldata->no_room) && receive_room(tty)) { |
205 | ldata->no_room = 0; | |
206 | ||
ecbbfd44 | 207 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 208 | "scheduling with invalid itty\n"); |
21622939 PH |
209 | /* see if ldisc has been killed - if so, this means that |
210 | * even though the ldisc has been halted and ->buf.work | |
211 | * cancelled, ->buf.work is about to be rescheduled | |
212 | */ | |
213 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
214 | "scheduling buffer work for halted ldisc\n"); | |
f0f947c1 | 215 | queue_work(system_unbound_wq, &tty->port->buf.work); |
ecbbfd44 | 216 | } |
55db4c64 LT |
217 | } |
218 | ||
9a4aec2d PH |
219 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
220 | { | |
221 | struct n_tty_data *ldata = tty->disc_data; | |
222 | ssize_t n = 0; | |
223 | ||
224 | if (!ldata->icanon) | |
225 | n = read_cnt(ldata); | |
226 | else | |
227 | n = ldata->canon_head - ldata->read_tail; | |
228 | return n; | |
229 | } | |
230 | ||
ee0bab83 PH |
231 | /** |
232 | * n_tty_write_wakeup - asynchronous I/O notifier | |
233 | * @tty: tty device | |
234 | * | |
235 | * Required for the ptys, serial driver etc. since processes | |
236 | * that attach themselves to the master and rely on ASYNC | |
237 | * IO must be woken up | |
238 | */ | |
239 | ||
240 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
241 | { | |
242 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) | |
243 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
244 | } | |
245 | ||
4a23a4df | 246 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 247 | { |
3afb1b39 PH |
248 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) |
249 | return; | |
6367ca72 PH |
250 | /* |
251 | * Check the remaining room for the input canonicalization | |
252 | * mode. We don't want to throttle the driver if we're in | |
253 | * canonical mode and don't have a newline yet! | |
254 | */ | |
255 | while (1) { | |
256 | int throttled; | |
257 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
258 | if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) | |
259 | break; | |
260 | throttled = tty_throttle_safe(tty); | |
261 | if (!throttled) | |
262 | break; | |
263 | } | |
264 | __tty_set_flow_change(tty, 0); | |
265 | } | |
266 | ||
267 | static inline void n_tty_check_unthrottle(struct tty_struct *tty) | |
268 | { | |
3afb1b39 PH |
269 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
270 | tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { | |
271 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
272 | return; | |
273 | if (!tty->count) | |
274 | return; | |
275 | n_tty_set_room(tty); | |
276 | n_tty_write_wakeup(tty->link); | |
277 | wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); | |
278 | return; | |
279 | } | |
280 | ||
6367ca72 PH |
281 | /* If there is enough space in the read buffer now, let the |
282 | * low-level driver know. We use chars_in_buffer() to | |
283 | * check the buffer, as it now knows about canonical mode. | |
284 | * Otherwise, if the driver is throttled and the line is | |
285 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
286 | * we won't get any more characters. | |
287 | */ | |
288 | ||
289 | while (1) { | |
290 | int unthrottled; | |
291 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
292 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
293 | break; | |
294 | if (!tty->count) | |
295 | break; | |
296 | n_tty_set_room(tty); | |
297 | unthrottled = tty_unthrottle_safe(tty); | |
298 | if (!unthrottled) | |
299 | break; | |
300 | } | |
301 | __tty_set_flow_change(tty, 0); | |
302 | } | |
303 | ||
17b82060 AC |
304 | /** |
305 | * put_tty_queue - add character to tty | |
306 | * @c: character | |
57c94121 | 307 | * @ldata: n_tty data |
17b82060 | 308 | * |
6d76bd26 PH |
309 | * Add a character to the tty read_buf queue. |
310 | * | |
311 | * n_tty_receive_buf()/producer path: | |
312 | * caller holds non-exclusive termios_rwsem | |
313 | * modifies read_head | |
314 | * | |
315 | * read_head is only considered 'published' if canonical mode is | |
316 | * not active. | |
17b82060 AC |
317 | */ |
318 | ||
57c94121 | 319 | static void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 320 | { |
6d76bd26 PH |
321 | if (read_cnt(ldata) < N_TTY_BUF_SIZE) { |
322 | *read_buf_addr(ldata, ldata->read_head) = c; | |
323 | ldata->read_head++; | |
324 | } | |
1da177e4 LT |
325 | } |
326 | ||
1da177e4 LT |
327 | /** |
328 | * reset_buffer_flags - reset buffer state | |
329 | * @tty: terminal to reset | |
330 | * | |
25518c68 PH |
331 | * Reset the read buffer counters and clear the flags. |
332 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 333 | * |
6d76bd26 PH |
334 | * Locking: caller holds exclusive termios_rwsem |
335 | * (or locking is not required) | |
1da177e4 | 336 | */ |
a88a69c9 | 337 | |
b66f4fa5 | 338 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 339 | { |
a73d3d69 | 340 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 341 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
40d5e090 | 342 | ldata->line_start = 0; |
a88a69c9 | 343 | |
a73d3d69 | 344 | ldata->erasing = 0; |
3fe780b3 | 345 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
1da177e4 LT |
346 | } |
347 | ||
a30737ab PH |
348 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
349 | { | |
350 | unsigned long flags; | |
351 | ||
352 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
353 | if (tty->link->packet) { | |
354 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
355 | wake_up_interruptible(&tty->link->read_wait); | |
356 | } | |
357 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
358 | } | |
359 | ||
1da177e4 LT |
360 | /** |
361 | * n_tty_flush_buffer - clean input queue | |
362 | * @tty: terminal device | |
363 | * | |
25518c68 PH |
364 | * Flush the input buffer. Called when the tty layer wants the |
365 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
366 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 367 | * |
6d76bd26 PH |
368 | * Holds termios_rwsem to exclude producer/consumer while |
369 | * buffer indices are reset. | |
370 | * | |
371 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 372 | */ |
4edf1827 AC |
373 | |
374 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 375 | { |
6d76bd26 | 376 | down_write(&tty->termios_rwsem); |
b66f4fa5 PH |
377 | reset_buffer_flags(tty->disc_data); |
378 | n_tty_set_room(tty); | |
4edf1827 | 379 | |
a30737ab PH |
380 | if (tty->link) |
381 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 382 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
383 | } |
384 | ||
6d76bd26 PH |
385 | /** |
386 | * n_tty_chars_in_buffer - report available bytes | |
387 | * @tty: tty device | |
388 | * | |
389 | * Report the number of characters buffered to be delivered to user | |
390 | * at this instant in time. | |
391 | * | |
392 | * Locking: exclusive termios_rwsem | |
393 | */ | |
394 | ||
a19d0c6a PH |
395 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
396 | { | |
6d76bd26 PH |
397 | ssize_t n; |
398 | ||
47534084 | 399 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
6d76bd26 PH |
400 | |
401 | down_write(&tty->termios_rwsem); | |
402 | n = chars_in_buffer(tty); | |
403 | up_write(&tty->termios_rwsem); | |
404 | return n; | |
a19d0c6a PH |
405 | } |
406 | ||
1da177e4 LT |
407 | /** |
408 | * is_utf8_continuation - utf8 multibyte check | |
409 | * @c: byte to check | |
410 | * | |
411 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
412 | * character. We use this to correctly compute the on screen size | |
413 | * of the character when printing | |
414 | */ | |
4edf1827 | 415 | |
1da177e4 LT |
416 | static inline int is_utf8_continuation(unsigned char c) |
417 | { | |
418 | return (c & 0xc0) == 0x80; | |
419 | } | |
420 | ||
421 | /** | |
422 | * is_continuation - multibyte check | |
423 | * @c: byte to check | |
424 | * | |
425 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
426 | * character and the terminal is in unicode mode. | |
427 | */ | |
4edf1827 | 428 | |
1da177e4 LT |
429 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
430 | { | |
431 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
432 | } | |
433 | ||
434 | /** | |
a88a69c9 | 435 | * do_output_char - output one character |
1da177e4 LT |
436 | * @c: character (or partial unicode symbol) |
437 | * @tty: terminal device | |
a88a69c9 | 438 | * @space: space available in tty driver write buffer |
1da177e4 | 439 | * |
a88a69c9 JP |
440 | * This is a helper function that handles one output character |
441 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
442 | * doing OPOST processing and putting the results in the |
443 | * tty driver's write buffer. | |
a88a69c9 JP |
444 | * |
445 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
446 | * and NLDLY. They simply aren't relevant in the world today. | |
447 | * If you ever need them, add them here. | |
1da177e4 | 448 | * |
a88a69c9 JP |
449 | * Returns the number of bytes of buffer space used or -1 if |
450 | * no space left. | |
451 | * | |
452 | * Locking: should be called under the output_lock to protect | |
453 | * the column state and space left in the buffer | |
1da177e4 | 454 | */ |
4edf1827 | 455 | |
a88a69c9 | 456 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 457 | { |
53c5ee2c | 458 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 459 | int spaces; |
1da177e4 | 460 | |
1da177e4 LT |
461 | if (!space) |
462 | return -1; | |
300a6204 | 463 | |
a88a69c9 JP |
464 | switch (c) { |
465 | case '\n': | |
466 | if (O_ONLRET(tty)) | |
53c5ee2c | 467 | ldata->column = 0; |
a88a69c9 JP |
468 | if (O_ONLCR(tty)) { |
469 | if (space < 2) | |
470 | return -1; | |
ba2e68ac | 471 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 472 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
473 | return 2; |
474 | } | |
ba2e68ac | 475 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
476 | break; |
477 | case '\r': | |
53c5ee2c | 478 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
479 | return 0; |
480 | if (O_OCRNL(tty)) { | |
481 | c = '\n'; | |
482 | if (O_ONLRET(tty)) | |
ba2e68ac | 483 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 484 | break; |
a88a69c9 | 485 | } |
ba2e68ac | 486 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
487 | break; |
488 | case '\t': | |
53c5ee2c | 489 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
490 | if (O_TABDLY(tty) == XTABS) { |
491 | if (space < spaces) | |
492 | return -1; | |
53c5ee2c | 493 | ldata->column += spaces; |
a88a69c9 JP |
494 | tty->ops->write(tty, " ", spaces); |
495 | return spaces; | |
1da177e4 | 496 | } |
53c5ee2c | 497 | ldata->column += spaces; |
a88a69c9 JP |
498 | break; |
499 | case '\b': | |
53c5ee2c JS |
500 | if (ldata->column > 0) |
501 | ldata->column--; | |
a88a69c9 JP |
502 | break; |
503 | default: | |
a59c0d6f JP |
504 | if (!iscntrl(c)) { |
505 | if (O_OLCUC(tty)) | |
506 | c = toupper(c); | |
507 | if (!is_continuation(c, tty)) | |
53c5ee2c | 508 | ldata->column++; |
a59c0d6f | 509 | } |
a88a69c9 | 510 | break; |
1da177e4 | 511 | } |
a88a69c9 | 512 | |
f34d7a5b | 513 | tty_put_char(tty, c); |
a88a69c9 JP |
514 | return 1; |
515 | } | |
516 | ||
517 | /** | |
518 | * process_output - output post processor | |
519 | * @c: character (or partial unicode symbol) | |
520 | * @tty: terminal device | |
521 | * | |
ee5aa7b8 JP |
522 | * Output one character with OPOST processing. |
523 | * Returns -1 when the output device is full and the character | |
524 | * must be retried. | |
a88a69c9 JP |
525 | * |
526 | * Locking: output_lock to protect column state and space left | |
527 | * (also, this is called from n_tty_write under the | |
528 | * tty layer write lock) | |
529 | */ | |
530 | ||
531 | static int process_output(unsigned char c, struct tty_struct *tty) | |
532 | { | |
bddc7152 | 533 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
534 | int space, retval; |
535 | ||
bddc7152 | 536 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
537 | |
538 | space = tty_write_room(tty); | |
539 | retval = do_output_char(c, tty, space); | |
540 | ||
bddc7152 | 541 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
542 | if (retval < 0) |
543 | return -1; | |
544 | else | |
545 | return 0; | |
1da177e4 LT |
546 | } |
547 | ||
548 | /** | |
a88a69c9 | 549 | * process_output_block - block post processor |
1da177e4 | 550 | * @tty: terminal device |
ee5aa7b8 JP |
551 | * @buf: character buffer |
552 | * @nr: number of bytes to output | |
553 | * | |
554 | * Output a block of characters with OPOST processing. | |
555 | * Returns the number of characters output. | |
1da177e4 LT |
556 | * |
557 | * This path is used to speed up block console writes, among other | |
558 | * things when processing blocks of output data. It handles only | |
559 | * the simple cases normally found and helps to generate blocks of | |
560 | * symbols for the console driver and thus improve performance. | |
561 | * | |
a88a69c9 JP |
562 | * Locking: output_lock to protect column state and space left |
563 | * (also, this is called from n_tty_write under the | |
564 | * tty layer write lock) | |
1da177e4 | 565 | */ |
4edf1827 | 566 | |
a88a69c9 JP |
567 | static ssize_t process_output_block(struct tty_struct *tty, |
568 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 569 | { |
53c5ee2c | 570 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 571 | int space; |
bbd20759 | 572 | int i; |
1da177e4 LT |
573 | const unsigned char *cp; |
574 | ||
bddc7152 | 575 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 576 | |
f34d7a5b | 577 | space = tty_write_room(tty); |
300a6204 | 578 | if (!space) { |
bddc7152 | 579 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 580 | return 0; |
a88a69c9 | 581 | } |
1da177e4 LT |
582 | if (nr > space) |
583 | nr = space; | |
584 | ||
585 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
586 | unsigned char c = *cp; |
587 | ||
588 | switch (c) { | |
1da177e4 LT |
589 | case '\n': |
590 | if (O_ONLRET(tty)) | |
53c5ee2c | 591 | ldata->column = 0; |
1da177e4 LT |
592 | if (O_ONLCR(tty)) |
593 | goto break_out; | |
ba2e68ac | 594 | ldata->canon_column = ldata->column; |
1da177e4 LT |
595 | break; |
596 | case '\r': | |
53c5ee2c | 597 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
598 | goto break_out; |
599 | if (O_OCRNL(tty)) | |
600 | goto break_out; | |
ba2e68ac | 601 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
602 | break; |
603 | case '\t': | |
604 | goto break_out; | |
605 | case '\b': | |
53c5ee2c JS |
606 | if (ldata->column > 0) |
607 | ldata->column--; | |
1da177e4 LT |
608 | break; |
609 | default: | |
a59c0d6f JP |
610 | if (!iscntrl(c)) { |
611 | if (O_OLCUC(tty)) | |
612 | goto break_out; | |
613 | if (!is_continuation(c, tty)) | |
53c5ee2c | 614 | ldata->column++; |
a59c0d6f | 615 | } |
1da177e4 LT |
616 | break; |
617 | } | |
618 | } | |
619 | break_out: | |
f34d7a5b | 620 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 621 | |
bddc7152 | 622 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
623 | return i; |
624 | } | |
625 | ||
a88a69c9 JP |
626 | /** |
627 | * process_echoes - write pending echo characters | |
628 | * @tty: terminal device | |
629 | * | |
630 | * Write previously buffered echo (and other ldisc-generated) | |
631 | * characters to the tty. | |
632 | * | |
633 | * Characters generated by the ldisc (including echoes) need to | |
634 | * be buffered because the driver's write buffer can fill during | |
635 | * heavy program output. Echoing straight to the driver will | |
636 | * often fail under these conditions, causing lost characters and | |
637 | * resulting mismatches of ldisc state information. | |
638 | * | |
639 | * Since the ldisc state must represent the characters actually sent | |
640 | * to the driver at the time of the write, operations like certain | |
641 | * changes in column state are also saved in the buffer and executed | |
642 | * here. | |
643 | * | |
644 | * A circular fifo buffer is used so that the most recent characters | |
645 | * are prioritized. Also, when control characters are echoed with a | |
646 | * prefixed "^", the pair is treated atomically and thus not separated. | |
647 | * | |
019ebdf9 | 648 | * Locking: callers must hold output_lock |
a88a69c9 JP |
649 | */ |
650 | ||
bc5b1ec5 | 651 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 652 | { |
53c5ee2c | 653 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 654 | int space, old_space; |
addaebcc | 655 | size_t tail; |
a88a69c9 | 656 | unsigned char c; |
a88a69c9 | 657 | |
bc5b1ec5 | 658 | old_space = space = tty_write_room(tty); |
a88a69c9 | 659 | |
addaebcc | 660 | tail = ldata->echo_tail; |
29c7c5ca | 661 | while (ldata->echo_commit != tail) { |
addaebcc | 662 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
663 | if (c == ECHO_OP_START) { |
664 | unsigned char op; | |
a88a69c9 JP |
665 | int no_space_left = 0; |
666 | ||
667 | /* | |
668 | * If the buffer byte is the start of a multi-byte | |
669 | * operation, get the next byte, which is either the | |
670 | * op code or a control character value. | |
671 | */ | |
addaebcc | 672 | op = echo_buf(ldata, tail + 1); |
300a6204 | 673 | |
a88a69c9 JP |
674 | switch (op) { |
675 | unsigned int num_chars, num_bs; | |
676 | ||
677 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 678 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
679 | |
680 | /* | |
681 | * Determine how many columns to go back | |
682 | * in order to erase the tab. | |
683 | * This depends on the number of columns | |
684 | * used by other characters within the tab | |
685 | * area. If this (modulo 8) count is from | |
686 | * the start of input rather than from a | |
687 | * previous tab, we offset by canon column. | |
688 | * Otherwise, tab spacing is normal. | |
689 | */ | |
690 | if (!(num_chars & 0x80)) | |
ba2e68ac | 691 | num_chars += ldata->canon_column; |
a88a69c9 JP |
692 | num_bs = 8 - (num_chars & 7); |
693 | ||
694 | if (num_bs > space) { | |
695 | no_space_left = 1; | |
696 | break; | |
697 | } | |
698 | space -= num_bs; | |
699 | while (num_bs--) { | |
700 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
701 | if (ldata->column > 0) |
702 | ldata->column--; | |
a88a69c9 | 703 | } |
addaebcc | 704 | tail += 3; |
a88a69c9 JP |
705 | break; |
706 | ||
707 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 708 | ldata->canon_column = ldata->column; |
addaebcc | 709 | tail += 2; |
a88a69c9 JP |
710 | break; |
711 | ||
712 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
713 | if (ldata->column > 0) |
714 | ldata->column--; | |
addaebcc | 715 | tail += 2; |
a88a69c9 JP |
716 | break; |
717 | ||
718 | case ECHO_OP_START: | |
719 | /* This is an escaped echo op start code */ | |
720 | if (!space) { | |
721 | no_space_left = 1; | |
722 | break; | |
723 | } | |
724 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 725 | ldata->column++; |
a88a69c9 | 726 | space--; |
addaebcc | 727 | tail += 2; |
a88a69c9 JP |
728 | break; |
729 | ||
730 | default: | |
a88a69c9 | 731 | /* |
62b26358 JP |
732 | * If the op is not a special byte code, |
733 | * it is a ctrl char tagged to be echoed | |
734 | * as "^X" (where X is the letter | |
735 | * representing the control char). | |
736 | * Note that we must ensure there is | |
737 | * enough space for the whole ctrl pair. | |
738 | * | |
a88a69c9 | 739 | */ |
62b26358 JP |
740 | if (space < 2) { |
741 | no_space_left = 1; | |
742 | break; | |
743 | } | |
744 | tty_put_char(tty, '^'); | |
745 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 746 | ldata->column += 2; |
62b26358 | 747 | space -= 2; |
addaebcc | 748 | tail += 2; |
a88a69c9 JP |
749 | } |
750 | ||
751 | if (no_space_left) | |
752 | break; | |
753 | } else { | |
582f5590 | 754 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
755 | int retval = do_output_char(c, tty, space); |
756 | if (retval < 0) | |
757 | break; | |
758 | space -= retval; | |
759 | } else { | |
760 | if (!space) | |
761 | break; | |
762 | tty_put_char(tty, c); | |
763 | space -= 1; | |
764 | } | |
addaebcc | 765 | tail += 1; |
a88a69c9 | 766 | } |
a88a69c9 JP |
767 | } |
768 | ||
cbfd0340 PH |
769 | /* If the echo buffer is nearly full (so that the possibility exists |
770 | * of echo overrun before the next commit), then discard enough | |
771 | * data at the tail to prevent a subsequent overrun */ | |
772 | while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
773 | if (echo_buf(ldata, tail == ECHO_OP_START)) { | |
774 | if (echo_buf(ldata, tail) == ECHO_OP_ERASE_TAB) | |
775 | tail += 3; | |
776 | else | |
777 | tail += 2; | |
778 | } else | |
779 | tail++; | |
780 | } | |
781 | ||
addaebcc | 782 | ldata->echo_tail = tail; |
bc5b1ec5 | 783 | return old_space - space; |
019ebdf9 PH |
784 | } |
785 | ||
786 | static void commit_echoes(struct tty_struct *tty) | |
787 | { | |
788 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 789 | size_t nr, old, echoed; |
cbfd0340 PH |
790 | size_t head; |
791 | ||
792 | head = ldata->echo_head; | |
793 | old = ldata->echo_commit - ldata->echo_tail; | |
794 | ||
795 | /* Process committed echoes if the accumulated # of bytes | |
796 | * is over the threshold (and try again each time another | |
797 | * block is accumulated) */ | |
798 | nr = head - ldata->echo_tail; | |
799 | if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) | |
800 | return; | |
a88a69c9 | 801 | |
019ebdf9 | 802 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 803 | ldata->echo_commit = head; |
bc5b1ec5 | 804 | echoed = __process_echoes(tty); |
bddc7152 | 805 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 806 | |
bc5b1ec5 | 807 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
808 | tty->ops->flush_chars(tty); |
809 | } | |
810 | ||
019ebdf9 | 811 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
812 | { |
813 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 814 | size_t echoed; |
17bd7907 | 815 | |
019ebdf9 PH |
816 | if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_tail) |
817 | return; | |
818 | ||
819 | mutex_lock(&ldata->output_lock); | |
bc5b1ec5 | 820 | echoed = __process_echoes(tty); |
019ebdf9 PH |
821 | mutex_unlock(&ldata->output_lock); |
822 | ||
bc5b1ec5 | 823 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 824 | tty->ops->flush_chars(tty); |
17bd7907 PH |
825 | } |
826 | ||
cbfd0340 PH |
827 | static void flush_echoes(struct tty_struct *tty) |
828 | { | |
829 | struct n_tty_data *ldata = tty->disc_data; | |
830 | ||
831 | if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_head) | |
832 | return; | |
833 | ||
834 | mutex_lock(&ldata->output_lock); | |
835 | ldata->echo_commit = ldata->echo_head; | |
836 | __process_echoes(tty); | |
837 | mutex_unlock(&ldata->output_lock); | |
838 | } | |
839 | ||
a88a69c9 JP |
840 | /** |
841 | * add_echo_byte - add a byte to the echo buffer | |
842 | * @c: unicode byte to echo | |
57c94121 | 843 | * @ldata: n_tty data |
a88a69c9 JP |
844 | * |
845 | * Add a character or operation byte to the echo buffer. | |
a88a69c9 JP |
846 | */ |
847 | ||
cbfd0340 | 848 | static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 849 | { |
addaebcc | 850 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
851 | } |
852 | ||
853 | /** | |
854 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 855 | * @ldata: n_tty data |
a88a69c9 JP |
856 | * |
857 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
858 | */ |
859 | ||
57c94121 | 860 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 861 | { |
57c94121 JS |
862 | add_echo_byte(ECHO_OP_START, ldata); |
863 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
864 | } |
865 | ||
866 | /** | |
867 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 868 | * @ldata: n_tty data |
a88a69c9 JP |
869 | * |
870 | * Add an operation to the echo buffer to set the canon column | |
871 | * to the current column. | |
a88a69c9 JP |
872 | */ |
873 | ||
57c94121 | 874 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 875 | { |
57c94121 JS |
876 | add_echo_byte(ECHO_OP_START, ldata); |
877 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
878 | } |
879 | ||
880 | /** | |
881 | * echo_erase_tab - add operation to erase a tab | |
882 | * @num_chars: number of character columns already used | |
883 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 884 | * @ldata: n_tty data |
a88a69c9 JP |
885 | * |
886 | * Add an operation to the echo buffer to erase a tab. | |
887 | * | |
888 | * Called by the eraser function, which knows how many character | |
889 | * columns have been used since either a previous tab or the start | |
890 | * of input. This information will be used later, along with | |
891 | * canon column (if applicable), to go back the correct number | |
892 | * of columns. | |
a88a69c9 JP |
893 | */ |
894 | ||
895 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 896 | struct n_tty_data *ldata) |
a88a69c9 | 897 | { |
57c94121 JS |
898 | add_echo_byte(ECHO_OP_START, ldata); |
899 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
900 | |
901 | /* We only need to know this modulo 8 (tab spacing) */ | |
902 | num_chars &= 7; | |
903 | ||
904 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
905 | if (after_tab) | |
906 | num_chars |= 0x80; | |
300a6204 | 907 | |
57c94121 | 908 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
909 | } |
910 | ||
911 | /** | |
912 | * echo_char_raw - echo a character raw | |
913 | * @c: unicode byte to echo | |
914 | * @tty: terminal device | |
915 | * | |
916 | * Echo user input back onto the screen. This must be called only when | |
917 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
918 | * | |
919 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
920 | */ |
921 | ||
57c94121 | 922 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 923 | { |
a88a69c9 | 924 | if (c == ECHO_OP_START) { |
57c94121 JS |
925 | add_echo_byte(ECHO_OP_START, ldata); |
926 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 927 | } else { |
57c94121 | 928 | add_echo_byte(c, ldata); |
a88a69c9 | 929 | } |
a88a69c9 | 930 | } |
1da177e4 | 931 | |
1da177e4 | 932 | /** |
a88a69c9 | 933 | * echo_char - echo a character |
1da177e4 LT |
934 | * @c: unicode byte to echo |
935 | * @tty: terminal device | |
936 | * | |
4edf1827 | 937 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 938 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 939 | * |
62b26358 JP |
940 | * This variant tags control characters to be echoed as "^X" |
941 | * (where X is the letter representing the control char). | |
1da177e4 LT |
942 | */ |
943 | ||
944 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
945 | { | |
bddc7152 JS |
946 | struct n_tty_data *ldata = tty->disc_data; |
947 | ||
a88a69c9 | 948 | if (c == ECHO_OP_START) { |
57c94121 JS |
949 | add_echo_byte(ECHO_OP_START, ldata); |
950 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 951 | } else { |
62b26358 | 952 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
953 | add_echo_byte(ECHO_OP_START, ldata); |
954 | add_echo_byte(c, ldata); | |
a88a69c9 | 955 | } |
1da177e4 LT |
956 | } |
957 | ||
17b82060 | 958 | /** |
a88a69c9 | 959 | * finish_erasing - complete erase |
57c94121 | 960 | * @ldata: n_tty data |
17b82060 | 961 | */ |
a88a69c9 | 962 | |
57c94121 | 963 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 964 | { |
53c5ee2c | 965 | if (ldata->erasing) { |
57c94121 | 966 | echo_char_raw('/', ldata); |
53c5ee2c | 967 | ldata->erasing = 0; |
1da177e4 LT |
968 | } |
969 | } | |
970 | ||
971 | /** | |
972 | * eraser - handle erase function | |
973 | * @c: character input | |
974 | * @tty: terminal device | |
975 | * | |
3a4fa0a2 | 976 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
977 | * present in the stream from the driver layer. Handles the complexities |
978 | * of UTF-8 multibyte symbols. | |
17b82060 | 979 | * |
6d76bd26 PH |
980 | * n_tty_receive_buf()/producer path: |
981 | * caller holds non-exclusive termios_rwsem | |
982 | * modifies read_head | |
983 | * | |
984 | * Modifying the read_head is not considered a publish in this context | |
985 | * because canonical mode is active -- only canon_head publishes | |
1da177e4 | 986 | */ |
4edf1827 | 987 | |
1da177e4 LT |
988 | static void eraser(unsigned char c, struct tty_struct *tty) |
989 | { | |
53c5ee2c | 990 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 991 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
992 | size_t head; |
993 | size_t cnt; | |
994 | int seen_alnums; | |
1da177e4 | 995 | |
ba2e68ac | 996 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 997 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
998 | return; |
999 | } | |
1000 | if (c == ERASE_CHAR(tty)) | |
1001 | kill_type = ERASE; | |
1002 | else if (c == WERASE_CHAR(tty)) | |
1003 | kill_type = WERASE; | |
1004 | else { | |
1005 | if (!L_ECHO(tty)) { | |
ba2e68ac | 1006 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
1007 | return; |
1008 | } | |
1009 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 1010 | ldata->read_head = ldata->canon_head; |
57c94121 | 1011 | finish_erasing(ldata); |
1da177e4 LT |
1012 | echo_char(KILL_CHAR(tty), tty); |
1013 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
1014 | if (L_ECHOK(tty)) | |
57c94121 | 1015 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1016 | return; |
1017 | } | |
1018 | kill_type = KILL; | |
1019 | } | |
1020 | ||
1021 | seen_alnums = 0; | |
ba2e68ac JS |
1022 | while (ldata->read_head != ldata->canon_head) { |
1023 | head = ldata->read_head; | |
1da177e4 LT |
1024 | |
1025 | /* erase a single possibly multibyte character */ | |
1026 | do { | |
bc5a5e3f PH |
1027 | head--; |
1028 | c = read_buf(ldata, head); | |
ba2e68ac | 1029 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1030 | |
1031 | /* do not partially erase */ | |
1032 | if (is_continuation(c, tty)) | |
1033 | break; | |
1034 | ||
1035 | if (kill_type == WERASE) { | |
1036 | /* Equivalent to BSD's ALTWERASE. */ | |
1037 | if (isalnum(c) || c == '_') | |
1038 | seen_alnums++; | |
1039 | else if (seen_alnums) | |
1040 | break; | |
1041 | } | |
bc5a5e3f | 1042 | cnt = ldata->read_head - head; |
ba2e68ac | 1043 | ldata->read_head = head; |
1da177e4 LT |
1044 | if (L_ECHO(tty)) { |
1045 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1046 | if (!ldata->erasing) { |
57c94121 | 1047 | echo_char_raw('\\', ldata); |
53c5ee2c | 1048 | ldata->erasing = 1; |
1da177e4 LT |
1049 | } |
1050 | /* if cnt > 1, output a multi-byte character */ | |
1051 | echo_char(c, tty); | |
1052 | while (--cnt > 0) { | |
bc5a5e3f PH |
1053 | head++; |
1054 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1055 | echo_move_back_col(ldata); |
1da177e4 LT |
1056 | } |
1057 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1058 | echo_char(ERASE_CHAR(tty), tty); | |
1059 | } else if (c == '\t') { | |
a88a69c9 JP |
1060 | unsigned int num_chars = 0; |
1061 | int after_tab = 0; | |
bc5a5e3f | 1062 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1063 | |
1064 | /* | |
1065 | * Count the columns used for characters | |
1066 | * since the start of input or after a | |
1067 | * previous tab. | |
1068 | * This info is used to go back the correct | |
1069 | * number of columns. | |
1070 | */ | |
ba2e68ac | 1071 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1072 | tail--; |
1073 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1074 | if (c == '\t') { |
1075 | after_tab = 1; | |
1076 | break; | |
300a6204 | 1077 | } else if (iscntrl(c)) { |
1da177e4 | 1078 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1079 | num_chars += 2; |
1080 | } else if (!is_continuation(c, tty)) { | |
1081 | num_chars++; | |
1082 | } | |
1da177e4 | 1083 | } |
57c94121 | 1084 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1085 | } else { |
1086 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1087 | echo_char_raw('\b', ldata); |
1088 | echo_char_raw(' ', ldata); | |
1089 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1090 | } |
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 | } | |
1097 | } | |
1098 | if (kill_type == ERASE) | |
1099 | break; | |
1100 | } | |
ba2e68ac | 1101 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1102 | finish_erasing(ldata); |
1da177e4 LT |
1103 | } |
1104 | ||
1105 | /** | |
1106 | * isig - handle the ISIG optio | |
1107 | * @sig: signal | |
1108 | * @tty: terminal | |
1da177e4 | 1109 | * |
8c985d18 PH |
1110 | * Called when a signal is being sent due to terminal input. |
1111 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1112 | * |
8c985d18 | 1113 | * Locking: ctrl_lock |
1da177e4 | 1114 | */ |
4edf1827 | 1115 | |
8c985d18 | 1116 | static inline void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1117 | { |
8c985d18 PH |
1118 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1119 | if (tty_pgrp) { | |
1120 | kill_pgrp(tty_pgrp, sig, 1); | |
1121 | put_pid(tty_pgrp); | |
1da177e4 LT |
1122 | } |
1123 | } | |
1124 | ||
1125 | /** | |
1126 | * n_tty_receive_break - handle break | |
1127 | * @tty: terminal | |
1128 | * | |
1129 | * An RS232 break event has been hit in the incoming bitstream. This | |
1130 | * can cause a variety of events depending upon the termios settings. | |
1131 | * | |
6d76bd26 PH |
1132 | * n_tty_receive_buf()/producer path: |
1133 | * caller holds non-exclusive termios_rwsem | |
1134 | * publishes read_head via put_tty_queue() | |
1135 | * | |
1136 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1137 | */ |
4edf1827 | 1138 | |
1da177e4 LT |
1139 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1140 | { | |
57c94121 JS |
1141 | struct n_tty_data *ldata = tty->disc_data; |
1142 | ||
1da177e4 LT |
1143 | if (I_IGNBRK(tty)) |
1144 | return; | |
1145 | if (I_BRKINT(tty)) { | |
8c985d18 PH |
1146 | isig(SIGINT, tty); |
1147 | if (!L_NOFLSH(tty)) { | |
6d76bd26 PH |
1148 | /* flushing needs exclusive termios_rwsem */ |
1149 | up_read(&tty->termios_rwsem); | |
8c985d18 PH |
1150 | n_tty_flush_buffer(tty); |
1151 | tty_driver_flush_buffer(tty); | |
6d76bd26 | 1152 | down_read(&tty->termios_rwsem); |
8c985d18 | 1153 | } |
1da177e4 LT |
1154 | return; |
1155 | } | |
1156 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1157 | put_tty_queue('\377', ldata); |
1158 | put_tty_queue('\0', ldata); | |
1da177e4 | 1159 | } |
57c94121 | 1160 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1161 | wake_up_interruptible(&tty->read_wait); |
1162 | } | |
1163 | ||
1164 | /** | |
1165 | * n_tty_receive_overrun - handle overrun reporting | |
1166 | * @tty: terminal | |
1167 | * | |
1168 | * Data arrived faster than we could process it. While the tty | |
1169 | * driver has flagged this the bits that were missed are gone | |
1170 | * forever. | |
1171 | * | |
1172 | * Called from the receive_buf path so single threaded. Does not | |
1173 | * need locking as num_overrun and overrun_time are function | |
1174 | * private. | |
1175 | */ | |
4edf1827 | 1176 | |
1da177e4 LT |
1177 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1178 | { | |
53c5ee2c | 1179 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1180 | char buf[64]; |
1181 | ||
53c5ee2c JS |
1182 | ldata->num_overrun++; |
1183 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1184 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1185 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1186 | tty_name(tty, buf), | |
53c5ee2c JS |
1187 | ldata->num_overrun); |
1188 | ldata->overrun_time = jiffies; | |
1189 | ldata->num_overrun = 0; | |
1da177e4 LT |
1190 | } |
1191 | } | |
1192 | ||
1193 | /** | |
1194 | * n_tty_receive_parity_error - error notifier | |
1195 | * @tty: terminal device | |
1196 | * @c: character | |
1197 | * | |
1198 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1199 | * the error case if necessary. |
1200 | * | |
1201 | * n_tty_receive_buf()/producer path: | |
1202 | * caller holds non-exclusive termios_rwsem | |
1203 | * publishes read_head via put_tty_queue() | |
1da177e4 LT |
1204 | */ |
1205 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1206 | unsigned char c) | |
1207 | { | |
57c94121 JS |
1208 | struct n_tty_data *ldata = tty->disc_data; |
1209 | ||
4edf1827 | 1210 | if (I_IGNPAR(tty)) |
1da177e4 | 1211 | return; |
1da177e4 | 1212 | if (I_PARMRK(tty)) { |
57c94121 JS |
1213 | put_tty_queue('\377', ldata); |
1214 | put_tty_queue('\0', ldata); | |
1215 | put_tty_queue(c, ldata); | |
1da177e4 | 1216 | } else if (I_INPCK(tty)) |
57c94121 | 1217 | put_tty_queue('\0', ldata); |
1da177e4 | 1218 | else |
57c94121 | 1219 | put_tty_queue(c, ldata); |
1da177e4 LT |
1220 | wake_up_interruptible(&tty->read_wait); |
1221 | } | |
1222 | ||
b0ac50be PH |
1223 | static void |
1224 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) | |
1225 | { | |
1226 | if (!L_NOFLSH(tty)) { | |
1227 | /* flushing needs exclusive termios_rwsem */ | |
1228 | up_read(&tty->termios_rwsem); | |
1229 | n_tty_flush_buffer(tty); | |
1230 | tty_driver_flush_buffer(tty); | |
1231 | down_read(&tty->termios_rwsem); | |
1232 | } | |
1233 | if (I_IXON(tty)) | |
1234 | start_tty(tty); | |
1235 | if (L_ECHO(tty)) { | |
1236 | echo_char(c, tty); | |
1237 | commit_echoes(tty); | |
1238 | } | |
1239 | isig(signal, tty); | |
1240 | return; | |
1241 | } | |
1242 | ||
1da177e4 LT |
1243 | /** |
1244 | * n_tty_receive_char - perform processing | |
1245 | * @tty: terminal device | |
1246 | * @c: character | |
1247 | * | |
1248 | * Process an individual character of input received from the driver. | |
4edf1827 | 1249 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1250 | * driver above. |
6d76bd26 PH |
1251 | * |
1252 | * n_tty_receive_buf()/producer path: | |
1253 | * caller holds non-exclusive termios_rwsem | |
1254 | * publishes canon_head if canonical mode is active | |
1255 | * otherwise, publishes read_head via put_tty_queue() | |
1da177e4 LT |
1256 | */ |
1257 | ||
4b1f79c2 PH |
1258 | static void |
1259 | n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) | |
1da177e4 | 1260 | { |
53c5ee2c | 1261 | struct n_tty_data *ldata = tty->disc_data; |
acc71bba | 1262 | int parmrk; |
1da177e4 | 1263 | |
1da177e4 LT |
1264 | if (I_IXON(tty)) { |
1265 | if (c == START_CHAR(tty)) { | |
1266 | start_tty(tty); | |
17bd7907 | 1267 | commit_echoes(tty); |
1da177e4 LT |
1268 | return; |
1269 | } | |
1270 | if (c == STOP_CHAR(tty)) { | |
1271 | stop_tty(tty); | |
1272 | return; | |
1273 | } | |
1274 | } | |
575537b3 | 1275 | |
1da177e4 | 1276 | if (L_ISIG(tty)) { |
b0ac50be PH |
1277 | if (c == INTR_CHAR(tty)) { |
1278 | n_tty_receive_signal_char(tty, SIGINT, c); | |
1279 | return; | |
1280 | } else if (c == QUIT_CHAR(tty)) { | |
1281 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
1282 | return; | |
1283 | } else if (c == SUSP_CHAR(tty)) { | |
1284 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
1da177e4 LT |
1285 | return; |
1286 | } | |
1287 | } | |
575537b3 | 1288 | |
855df3c0 PH |
1289 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { |
1290 | start_tty(tty); | |
1291 | process_echoes(tty); | |
1292 | } | |
1293 | ||
575537b3 JP |
1294 | if (c == '\r') { |
1295 | if (I_IGNCR(tty)) | |
1296 | return; | |
1297 | if (I_ICRNL(tty)) | |
1298 | c = '\n'; | |
1299 | } else if (c == '\n' && I_INLCR(tty)) | |
1300 | c = '\r'; | |
1301 | ||
53c5ee2c | 1302 | if (ldata->icanon) { |
1da177e4 LT |
1303 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1304 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1305 | eraser(c, tty); | |
17bd7907 | 1306 | commit_echoes(tty); |
1da177e4 LT |
1307 | return; |
1308 | } | |
1309 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1310 | ldata->lnext = 1; |
1da177e4 | 1311 | if (L_ECHO(tty)) { |
57c94121 | 1312 | finish_erasing(ldata); |
1da177e4 | 1313 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1314 | echo_char_raw('^', ldata); |
1315 | echo_char_raw('\b', ldata); | |
17bd7907 | 1316 | commit_echoes(tty); |
1da177e4 LT |
1317 | } |
1318 | } | |
1319 | return; | |
1320 | } | |
1321 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1322 | L_IEXTEN(tty)) { | |
bc5a5e3f | 1323 | size_t tail = ldata->canon_head; |
1da177e4 | 1324 | |
57c94121 | 1325 | finish_erasing(ldata); |
1da177e4 | 1326 | echo_char(c, tty); |
57c94121 | 1327 | echo_char_raw('\n', ldata); |
ba2e68ac | 1328 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1329 | echo_char(read_buf(ldata, tail), tty); |
1330 | tail++; | |
1da177e4 | 1331 | } |
17bd7907 | 1332 | commit_echoes(tty); |
1da177e4 LT |
1333 | return; |
1334 | } | |
1335 | if (c == '\n') { | |
ce74117a | 1336 | if (read_cnt(ldata) >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1337 | if (L_ECHO(tty)) |
1338 | process_output('\a', tty); | |
acc71bba JP |
1339 | return; |
1340 | } | |
1341 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
57c94121 | 1342 | echo_char_raw('\n', ldata); |
17bd7907 | 1343 | commit_echoes(tty); |
1da177e4 LT |
1344 | } |
1345 | goto handle_newline; | |
1346 | } | |
1347 | if (c == EOF_CHAR(tty)) { | |
ce74117a | 1348 | if (read_cnt(ldata) >= N_TTY_BUF_SIZE) |
acc71bba | 1349 | return; |
1da177e4 LT |
1350 | c = __DISABLED_CHAR; |
1351 | goto handle_newline; | |
1352 | } | |
1353 | if ((c == EOL_CHAR(tty)) || | |
1354 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1355 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1356 | ? 1 : 0; | |
ce74117a | 1357 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk)) { |
7e94b1d9 JP |
1358 | if (L_ECHO(tty)) |
1359 | process_output('\a', tty); | |
acc71bba JP |
1360 | return; |
1361 | } | |
1da177e4 LT |
1362 | /* |
1363 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1364 | */ | |
1365 | if (L_ECHO(tty)) { | |
1da177e4 | 1366 | /* Record the column of first canon char. */ |
ba2e68ac | 1367 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1368 | echo_set_canon_col(ldata); |
1da177e4 | 1369 | echo_char(c, tty); |
17bd7907 | 1370 | commit_echoes(tty); |
1da177e4 LT |
1371 | } |
1372 | /* | |
1373 | * XXX does PARMRK doubling happen for | |
1374 | * EOL_CHAR and EOL2_CHAR? | |
1375 | */ | |
acc71bba | 1376 | if (parmrk) |
57c94121 | 1377 | put_tty_queue(c, ldata); |
1da177e4 | 1378 | |
4edf1827 | 1379 | handle_newline: |
bc5a5e3f | 1380 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1381 | put_tty_queue(c, ldata); |
ba2e68ac | 1382 | ldata->canon_head = ldata->read_head; |
1da177e4 LT |
1383 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1384 | if (waitqueue_active(&tty->read_wait)) | |
1385 | wake_up_interruptible(&tty->read_wait); | |
1386 | return; | |
1387 | } | |
1388 | } | |
4edf1827 | 1389 | |
acc71bba | 1390 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ce74117a | 1391 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1392 | /* beep if no space */ |
7e94b1d9 JP |
1393 | if (L_ECHO(tty)) |
1394 | process_output('\a', tty); | |
acc71bba JP |
1395 | return; |
1396 | } | |
1397 | if (L_ECHO(tty)) { | |
57c94121 | 1398 | finish_erasing(ldata); |
1da177e4 | 1399 | if (c == '\n') |
57c94121 | 1400 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1401 | else { |
1402 | /* Record the column of first canon char. */ | |
ba2e68ac | 1403 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1404 | echo_set_canon_col(ldata); |
1da177e4 LT |
1405 | echo_char(c, tty); |
1406 | } | |
17bd7907 | 1407 | commit_echoes(tty); |
1da177e4 LT |
1408 | } |
1409 | ||
acc71bba | 1410 | if (parmrk) |
57c94121 | 1411 | put_tty_queue(c, ldata); |
1da177e4 | 1412 | |
57c94121 | 1413 | put_tty_queue(c, ldata); |
4edf1827 | 1414 | } |
1da177e4 | 1415 | |
4b1f79c2 PH |
1416 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) |
1417 | { | |
1418 | struct n_tty_data *ldata = tty->disc_data; | |
1419 | int parmrk; | |
1420 | ||
4b1f79c2 PH |
1421 | /* |
1422 | * If the previous character was LNEXT, or we know that this | |
1423 | * character is not one of the characters that we'll have to | |
1424 | * handle specially, do shortcut processing to speed things | |
1425 | * up. | |
1426 | */ | |
1427 | if (!test_bit(c, ldata->char_map) || ldata->lnext) { | |
1428 | ldata->lnext = 0; | |
1429 | ||
1430 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && | |
1431 | I_IXANY(tty)) { | |
1432 | start_tty(tty); | |
1433 | process_echoes(tty); | |
1434 | } | |
1435 | ||
1436 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; | |
1437 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) { | |
1438 | /* beep if no space */ | |
1439 | if (L_ECHO(tty)) | |
1440 | process_output('\a', tty); | |
1441 | return; | |
1442 | } | |
1443 | if (L_ECHO(tty)) { | |
1444 | finish_erasing(ldata); | |
1445 | /* Record the column of first canon char. */ | |
1446 | if (ldata->canon_head == ldata->read_head) | |
1447 | echo_set_canon_col(ldata); | |
1448 | echo_char(c, tty); | |
1449 | commit_echoes(tty); | |
1450 | } | |
1451 | if (parmrk) | |
1452 | put_tty_queue(c, ldata); | |
1453 | put_tty_queue(c, ldata); | |
1454 | return; | |
1455 | } | |
1456 | ||
1457 | n_tty_receive_char_special(tty, c); | |
1458 | } | |
1459 | ||
7de971b0 PH |
1460 | static inline void |
1461 | n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) | |
1462 | { | |
1463 | struct n_tty_data *ldata = tty->disc_data; | |
1464 | ||
1465 | /* | |
1466 | * If the previous character was LNEXT, or we know that this | |
1467 | * character is not one of the characters that we'll have to | |
1468 | * handle specially, do shortcut processing to speed things | |
1469 | * up. | |
1470 | */ | |
1471 | if (!test_bit(c, ldata->char_map) || ldata->lnext) { | |
1472 | ldata->lnext = 0; | |
1473 | ||
1474 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && | |
1475 | I_IXANY(tty)) { | |
1476 | start_tty(tty); | |
1477 | process_echoes(tty); | |
1478 | } | |
1479 | ||
1480 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - 1)) { | |
1481 | /* beep if no space */ | |
1482 | if (L_ECHO(tty)) | |
1483 | process_output('\a', tty); | |
1484 | return; | |
1485 | } | |
1486 | if (L_ECHO(tty)) { | |
1487 | finish_erasing(ldata); | |
1488 | /* Record the column of first canon char. */ | |
1489 | if (ldata->canon_head == ldata->read_head) | |
1490 | echo_set_canon_col(ldata); | |
1491 | echo_char(c, tty); | |
1492 | commit_echoes(tty); | |
1493 | } | |
1494 | put_tty_queue(c, ldata); | |
1495 | return; | |
1496 | } | |
1497 | ||
1498 | n_tty_receive_char_special(tty, c); | |
1499 | } | |
1500 | ||
ad0cc7ba PH |
1501 | static inline void |
1502 | n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) | |
1503 | { | |
1504 | if (I_ISTRIP(tty)) | |
1505 | c &= 0x7f; | |
1506 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1507 | c = tolower(c); | |
1508 | ||
1509 | if (I_IXON(tty)) { | |
1510 | if (c == STOP_CHAR(tty)) | |
1511 | stop_tty(tty); | |
1512 | else if (c == START_CHAR(tty) || | |
1513 | (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && | |
1514 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1515 | c != SUSP_CHAR(tty))) { | |
1516 | start_tty(tty); | |
1517 | process_echoes(tty); | |
1518 | } | |
1519 | } | |
1520 | } | |
1521 | ||
d2f8d7ab PH |
1522 | static void |
1523 | n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) | |
1524 | { | |
1525 | char buf[64]; | |
1526 | ||
1527 | switch (flag) { | |
1528 | case TTY_BREAK: | |
1529 | n_tty_receive_break(tty); | |
1530 | break; | |
1531 | case TTY_PARITY: | |
1532 | case TTY_FRAME: | |
1533 | n_tty_receive_parity_error(tty, c); | |
1534 | break; | |
1535 | case TTY_OVERRUN: | |
1536 | n_tty_receive_overrun(tty); | |
1537 | break; | |
1538 | default: | |
1539 | printk(KERN_ERR "%s: unknown flag %d\n", | |
1540 | tty_name(tty, buf), flag); | |
1541 | break; | |
1542 | } | |
1543 | } | |
1544 | ||
1da177e4 LT |
1545 | /** |
1546 | * n_tty_receive_buf - data receive | |
1547 | * @tty: terminal device | |
1548 | * @cp: buffer | |
1549 | * @fp: flag buffer | |
1550 | * @count: characters | |
1551 | * | |
1552 | * Called by the terminal driver when a block of characters has | |
1553 | * been received. This function must be called from soft contexts | |
1554 | * not from interrupt context. The driver is responsible for making | |
1555 | * calls one at a time and in order (or using flush_to_ldisc) | |
6d76bd26 PH |
1556 | * |
1557 | * n_tty_receive_buf()/producer path: | |
1558 | * claims non-exclusive termios_rwsem | |
1559 | * publishes read_head and canon_head | |
1da177e4 | 1560 | */ |
4edf1827 | 1561 | |
4a23a4df PH |
1562 | static void |
1563 | n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, | |
1564 | char *fp, int count) | |
1565 | { | |
1566 | struct n_tty_data *ldata = tty->disc_data; | |
1567 | size_t n, head; | |
1568 | ||
1569 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1570 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1571 | n = min_t(size_t, count, n); | |
1572 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1573 | ldata->read_head += n; | |
1574 | cp += n; | |
1575 | count -= n; | |
1576 | ||
1577 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1578 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1579 | n = min_t(size_t, count, n); | |
1580 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1581 | ldata->read_head += n; | |
1582 | } | |
1583 | ||
554117bd PH |
1584 | static void |
1585 | n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, | |
1586 | char *fp, int count) | |
1587 | { | |
1588 | struct n_tty_data *ldata = tty->disc_data; | |
1589 | char flag = TTY_NORMAL; | |
1590 | ||
1591 | while (count--) { | |
1592 | if (fp) | |
1593 | flag = *fp++; | |
1594 | if (likely(flag == TTY_NORMAL)) | |
1595 | put_tty_queue(*cp++, ldata); | |
1596 | else | |
1597 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1598 | } | |
1599 | } | |
1600 | ||
ad0cc7ba PH |
1601 | static void |
1602 | n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, | |
1603 | char *fp, int count) | |
1604 | { | |
1605 | char flag = TTY_NORMAL; | |
1606 | ||
1607 | while (count--) { | |
1608 | if (fp) | |
1609 | flag = *fp++; | |
1610 | if (likely(flag == TTY_NORMAL)) | |
1611 | n_tty_receive_char_closing(tty, *cp++); | |
1612 | else | |
1613 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1614 | } | |
1615 | } | |
1616 | ||
7d88d637 PH |
1617 | static void |
1618 | n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, | |
6baad008 PH |
1619 | char *fp, int count) |
1620 | { | |
1621 | struct n_tty_data *ldata = tty->disc_data; | |
1622 | char flag = TTY_NORMAL; | |
1623 | ||
1624 | while (count--) { | |
1625 | if (fp) | |
1626 | flag = *fp++; | |
1627 | if (likely(flag == TTY_NORMAL)) { | |
1628 | unsigned char c = *cp++; | |
1629 | ||
1630 | if (I_ISTRIP(tty)) | |
1631 | c &= 0x7f; | |
1632 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1633 | c = tolower(c); | |
1634 | if (L_EXTPROC(tty)) { | |
1635 | put_tty_queue(c, ldata); | |
1636 | continue; | |
1637 | } | |
1638 | n_tty_receive_char(tty, c); | |
1639 | } else | |
1640 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1641 | } | |
1642 | } | |
1643 | ||
1644 | static void | |
1645 | n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, | |
1646 | char *fp, int count) | |
7d88d637 PH |
1647 | { |
1648 | char flag = TTY_NORMAL; | |
1649 | ||
1650 | while (count--) { | |
1651 | if (fp) | |
1652 | flag = *fp++; | |
1653 | if (likely(flag == TTY_NORMAL)) | |
7de971b0 | 1654 | n_tty_receive_char_fast(tty, *cp++); |
7d88d637 PH |
1655 | else |
1656 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1657 | } | |
1658 | } | |
1659 | ||
24a89d1c PH |
1660 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1661 | char *fp, int count) | |
1da177e4 | 1662 | { |
53c5ee2c | 1663 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1664 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
1da177e4 | 1665 | |
4a23a4df PH |
1666 | if (ldata->real_raw) |
1667 | n_tty_receive_buf_real_raw(tty, cp, fp, count); | |
a1dd30e9 | 1668 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1669 | n_tty_receive_buf_raw(tty, cp, fp, count); |
ad0cc7ba PH |
1670 | else if (tty->closing && !L_EXTPROC(tty)) |
1671 | n_tty_receive_buf_closing(tty, cp, fp, count); | |
4a23a4df | 1672 | else { |
7de971b0 | 1673 | if (!preops && !I_PARMRK(tty)) |
6baad008 PH |
1674 | n_tty_receive_buf_fast(tty, cp, fp, count); |
1675 | else | |
1676 | n_tty_receive_buf_standard(tty, cp, fp, count); | |
cbfd0340 PH |
1677 | |
1678 | flush_echoes(tty); | |
f34d7a5b AC |
1679 | if (tty->ops->flush_chars) |
1680 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1681 | } |
1682 | ||
ce74117a | 1683 | if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) || |
26df6d13 | 1684 | L_EXTPROC(tty)) { |
1da177e4 LT |
1685 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1686 | if (waitqueue_active(&tty->read_wait)) | |
1687 | wake_up_interruptible(&tty->read_wait); | |
1688 | } | |
1da177e4 LT |
1689 | } |
1690 | ||
24a89d1c PH |
1691 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1692 | char *fp, int count) | |
1693 | { | |
9356b535 | 1694 | down_read(&tty->termios_rwsem); |
24a89d1c | 1695 | __receive_buf(tty, cp, fp, count); |
4a23a4df | 1696 | n_tty_check_throttle(tty); |
9356b535 | 1697 | up_read(&tty->termios_rwsem); |
24a89d1c PH |
1698 | } |
1699 | ||
1700 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1701 | char *fp, int count) | |
1702 | { | |
1703 | struct n_tty_data *ldata = tty->disc_data; | |
1704 | int room; | |
1705 | ||
9356b535 PH |
1706 | down_read(&tty->termios_rwsem); |
1707 | ||
24a89d1c PH |
1708 | tty->receive_room = room = receive_room(tty); |
1709 | if (!room) | |
1710 | ldata->no_room = 1; | |
1711 | count = min(count, room); | |
4a23a4df | 1712 | if (count) { |
24a89d1c | 1713 | __receive_buf(tty, cp, fp, count); |
4a23a4df PH |
1714 | n_tty_check_throttle(tty); |
1715 | } | |
24a89d1c | 1716 | |
9356b535 PH |
1717 | up_read(&tty->termios_rwsem); |
1718 | ||
24a89d1c PH |
1719 | return count; |
1720 | } | |
1721 | ||
1da177e4 LT |
1722 | int is_ignored(int sig) |
1723 | { | |
1724 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1725 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1726 | } |
1727 | ||
1728 | /** | |
1729 | * n_tty_set_termios - termios data changed | |
1730 | * @tty: terminal | |
1731 | * @old: previous data | |
1732 | * | |
1733 | * Called by the tty layer when the user changes termios flags so | |
1734 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1735 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1736 | * guaranteed that this function will not be re-entered or in progress |
1737 | * when the ldisc is closed. | |
17b82060 | 1738 | * |
6a1c0680 | 1739 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1740 | */ |
4edf1827 AC |
1741 | |
1742 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1743 | { |
53c5ee2c | 1744 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1745 | int canon_change = 1; |
47afa7a5 AC |
1746 | |
1747 | if (old) | |
adc8d746 | 1748 | canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON; |
47afa7a5 | 1749 | if (canon_change) { |
3fe780b3 | 1750 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
40d5e090 | 1751 | ldata->line_start = 0; |
ba2e68ac | 1752 | ldata->canon_head = ldata->read_tail; |
53c5ee2c | 1753 | ldata->erasing = 0; |
6f9b028a | 1754 | ldata->lnext = 0; |
47afa7a5 AC |
1755 | } |
1756 | ||
ce74117a | 1757 | if (canon_change && !L_ICANON(tty) && read_cnt(ldata)) |
47afa7a5 | 1758 | wake_up_interruptible(&tty->read_wait); |
4edf1827 | 1759 | |
53c5ee2c | 1760 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1761 | |
1da177e4 LT |
1762 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1763 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1764 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1765 | I_PARMRK(tty)) { | |
1bb9d562 | 1766 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1767 | |
1768 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1769 | set_bit('\r', ldata->char_map); |
1da177e4 | 1770 | if (I_INLCR(tty)) |
1bb9d562 | 1771 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1772 | |
1773 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1774 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1775 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1776 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1777 | set_bit('\n', ldata->char_map); | |
1778 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1779 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1780 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1781 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1782 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1783 | if (L_ECHO(tty)) |
1784 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1785 | ldata->char_map); |
1da177e4 LT |
1786 | } |
1787 | } | |
1788 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1789 | set_bit(START_CHAR(tty), ldata->char_map); |
1790 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1791 | } |
1792 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1793 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1794 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1795 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1796 | } |
1bb9d562 | 1797 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1798 | ldata->raw = 0; |
1799 | ldata->real_raw = 0; | |
1da177e4 | 1800 | } else { |
53c5ee2c | 1801 | ldata->raw = 1; |
1da177e4 LT |
1802 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1803 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1804 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1805 | ldata->real_raw = 1; |
1da177e4 | 1806 | else |
53c5ee2c | 1807 | ldata->real_raw = 0; |
1da177e4 | 1808 | } |
55db4c64 | 1809 | n_tty_set_room(tty); |
dab73b4e WY |
1810 | /* |
1811 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1812 | * been stopped by STOP_CHAR(tty) before it. | |
1813 | */ | |
1814 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { | |
1815 | start_tty(tty); | |
1816 | } | |
1817 | ||
f34d7a5b AC |
1818 | /* The termios change make the tty ready for I/O */ |
1819 | wake_up_interruptible(&tty->write_wait); | |
1820 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1821 | } |
1822 | ||
1823 | /** | |
1824 | * n_tty_close - close the ldisc for this tty | |
1825 | * @tty: device | |
1826 | * | |
4edf1827 AC |
1827 | * Called from the terminal layer when this line discipline is |
1828 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1829 | * discipline change. The function will not be called while other |
1830 | * ldisc methods are in progress. | |
1831 | */ | |
4edf1827 | 1832 | |
1da177e4 LT |
1833 | static void n_tty_close(struct tty_struct *tty) |
1834 | { | |
70ece7a7 JS |
1835 | struct n_tty_data *ldata = tty->disc_data; |
1836 | ||
79901317 PH |
1837 | if (tty->link) |
1838 | n_tty_packet_mode_flush(tty); | |
1839 | ||
20bafb3d | 1840 | vfree(ldata); |
70ece7a7 | 1841 | tty->disc_data = NULL; |
1da177e4 LT |
1842 | } |
1843 | ||
1844 | /** | |
1845 | * n_tty_open - open an ldisc | |
1846 | * @tty: terminal to open | |
1847 | * | |
4edf1827 | 1848 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1849 | * terminal device. Can sleep. Called serialized so that no |
1850 | * other events will occur in parallel. No further open will occur | |
1851 | * until a close. | |
1852 | */ | |
1853 | ||
1854 | static int n_tty_open(struct tty_struct *tty) | |
1855 | { | |
70ece7a7 JS |
1856 | struct n_tty_data *ldata; |
1857 | ||
20bafb3d PH |
1858 | /* Currently a malloc failure here can panic */ |
1859 | ldata = vmalloc(sizeof(*ldata)); | |
70ece7a7 JS |
1860 | if (!ldata) |
1861 | goto err; | |
1862 | ||
53c5ee2c | 1863 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1864 | mutex_init(&ldata->atomic_read_lock); |
1865 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1866 | |
70ece7a7 | 1867 | tty->disc_data = ldata; |
b66f4fa5 | 1868 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1869 | ldata->column = 0; |
20bafb3d | 1870 | ldata->canon_column = 0; |
f6c8dbe6 | 1871 | ldata->minimum_to_wake = 1; |
20bafb3d PH |
1872 | ldata->num_overrun = 0; |
1873 | ldata->no_room = 0; | |
1874 | ldata->lnext = 0; | |
1da177e4 | 1875 | tty->closing = 0; |
b66f4fa5 PH |
1876 | /* indicate buffer work may resume */ |
1877 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1878 | n_tty_set_termios(tty, NULL); | |
1879 | tty_unthrottle(tty); | |
70ece7a7 | 1880 | |
1da177e4 | 1881 | return 0; |
70ece7a7 | 1882 | err: |
b91939f5 | 1883 | return -ENOMEM; |
1da177e4 LT |
1884 | } |
1885 | ||
1886 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1887 | { | |
53c5ee2c JS |
1888 | struct n_tty_data *ldata = tty->disc_data; |
1889 | ||
53c5ee2c | 1890 | if (ldata->icanon && !L_EXTPROC(tty)) { |
a73d3d69 | 1891 | if (ldata->canon_head != ldata->read_tail) |
1da177e4 | 1892 | return 1; |
ce74117a | 1893 | } else if (read_cnt(ldata) >= (amt ? amt : 1)) |
1da177e4 LT |
1894 | return 1; |
1895 | ||
1896 | return 0; | |
1897 | } | |
1898 | ||
1899 | /** | |
bbd20759 | 1900 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1901 | * @tty: terminal device |
1902 | * @b: user data | |
1903 | * @nr: size of data | |
1904 | * | |
11a96d18 | 1905 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1906 | * ICANON is off; it copies characters straight from the tty queue to |
1907 | * user space directly. It can be profitably called twice; once to | |
1908 | * drain the space from the tail pointer to the (physical) end of the | |
1909 | * buffer, and once to drain the space from the (physical) beginning of | |
1910 | * the buffer to head pointer. | |
1911 | * | |
bddc7152 | 1912 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1913 | * |
6d76bd26 PH |
1914 | * n_tty_read()/consumer path: |
1915 | * caller holds non-exclusive termios_rwsem | |
1916 | * read_tail published | |
1da177e4 | 1917 | */ |
4edf1827 | 1918 | |
33f0f88f | 1919 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1920 | unsigned char __user **b, |
1921 | size_t *nr) | |
1922 | ||
1923 | { | |
53c5ee2c | 1924 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1925 | int retval; |
1926 | size_t n; | |
3fa10cc8 | 1927 | bool is_eof; |
bc5a5e3f | 1928 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1929 | |
1930 | retval = 0; | |
bc5a5e3f | 1931 | n = min(read_cnt(ldata), N_TTY_BUF_SIZE - tail); |
1da177e4 | 1932 | n = min(*nr, n); |
1da177e4 | 1933 | if (n) { |
bc5a5e3f | 1934 | retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
1da177e4 | 1935 | n -= retval; |
bc5a5e3f PH |
1936 | is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); |
1937 | tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, | |
53c5ee2c | 1938 | ldata->icanon); |
bc5a5e3f | 1939 | ldata->read_tail += n; |
26df6d13 | 1940 | /* Turn single EOF into zero-length read */ |
ce74117a | 1941 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !read_cnt(ldata)) |
3fa10cc8 | 1942 | n = 0; |
1da177e4 LT |
1943 | *b += n; |
1944 | *nr -= n; | |
1945 | } | |
1946 | return retval; | |
1947 | } | |
1948 | ||
88bb0de3 | 1949 | /** |
32f13521 | 1950 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1951 | * @tty: terminal device |
1952 | * @b: user data | |
1953 | * @nr: size of data | |
1954 | * | |
1955 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1956 | * it copies one line of input up to and including the line-delimiting |
1957 | * character into the user-space buffer. | |
88bb0de3 PH |
1958 | * |
1959 | * Called under the atomic_read_lock mutex | |
6d76bd26 PH |
1960 | * |
1961 | * n_tty_read()/consumer path: | |
1962 | * caller holds non-exclusive termios_rwsem | |
1963 | * read_tail published | |
88bb0de3 PH |
1964 | */ |
1965 | ||
32f13521 PH |
1966 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
1967 | unsigned char __user **b, | |
1968 | size_t *nr) | |
88bb0de3 PH |
1969 | { |
1970 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 1971 | size_t n, size, more, c; |
bc5a5e3f PH |
1972 | size_t eol; |
1973 | size_t tail; | |
1974 | int ret, found = 0; | |
40d5e090 | 1975 | bool eof_push = 0; |
88bb0de3 PH |
1976 | |
1977 | /* N.B. avoid overrun if nr == 0 */ | |
ce74117a | 1978 | n = min(*nr, read_cnt(ldata)); |
6d76bd26 | 1979 | if (!n) |
32f13521 | 1980 | return 0; |
88bb0de3 | 1981 | |
bc5a5e3f | 1982 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
1983 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
1984 | ||
bc5a5e3f | 1985 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
1986 | __func__, *nr, tail, n, size); |
1987 | ||
1988 | eol = find_next_bit(ldata->read_flags, size, tail); | |
1989 | more = n - (size - tail); | |
1990 | if (eol == N_TTY_BUF_SIZE && more) { | |
1991 | /* scan wrapped without finding set bit */ | |
1992 | eol = find_next_bit(ldata->read_flags, more, 0); | |
1993 | if (eol != more) | |
1994 | found = 1; | |
1995 | } else if (eol != size) | |
1996 | found = 1; | |
1997 | ||
1998 | size = N_TTY_BUF_SIZE - tail; | |
1999 | n = (found + eol + size) & (N_TTY_BUF_SIZE - 1); | |
2000 | c = n; | |
2001 | ||
40d5e090 | 2002 | if (found && read_buf(ldata, eol) == __DISABLED_CHAR) { |
32f13521 | 2003 | n--; |
40d5e090 PH |
2004 | eof_push = !n && ldata->read_tail != ldata->line_start; |
2005 | } | |
32f13521 | 2006 | |
bc5a5e3f | 2007 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", |
32f13521 PH |
2008 | __func__, eol, found, n, c, size, more); |
2009 | ||
32f13521 | 2010 | if (n > size) { |
bc5a5e3f | 2011 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), size); |
32f13521 PH |
2012 | if (ret) |
2013 | return -EFAULT; | |
2014 | ret = copy_to_user(*b + size, ldata->read_buf, n - size); | |
2015 | } else | |
bc5a5e3f | 2016 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
32f13521 PH |
2017 | |
2018 | if (ret) | |
2019 | return -EFAULT; | |
2020 | *b += n; | |
2021 | *nr -= n; | |
2022 | ||
a73d3d69 | 2023 | if (found) |
6d76bd26 PH |
2024 | clear_bit(eol, ldata->read_flags); |
2025 | smp_mb__after_clear_bit(); | |
2026 | ldata->read_tail += c; | |
88bb0de3 | 2027 | |
40d5e090 PH |
2028 | if (found) { |
2029 | ldata->line_start = ldata->read_tail; | |
32f13521 | 2030 | tty_audit_push(tty); |
40d5e090 PH |
2031 | } |
2032 | return eof_push ? -EAGAIN : 0; | |
88bb0de3 PH |
2033 | } |
2034 | ||
cc4191dc | 2035 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 2036 | size_t, loff_t *); |
1da177e4 LT |
2037 | |
2038 | /** | |
2039 | * job_control - check job control | |
2040 | * @tty: tty | |
2041 | * @file: file handle | |
2042 | * | |
2043 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 2044 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 2045 | * error code if action should be taken. |
04f378b1 | 2046 | * |
01a5e440 PH |
2047 | * Locking: redirected write test is safe |
2048 | * current->signal->tty check is safe | |
2049 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 2050 | */ |
4edf1827 | 2051 | |
1da177e4 LT |
2052 | static int job_control(struct tty_struct *tty, struct file *file) |
2053 | { | |
2054 | /* Job control check -- must be done at start and after | |
2055 | every sleep (POSIX.1 7.1.1.4). */ | |
2056 | /* NOTE: not yet done after every sleep pending a thorough | |
2057 | check of the logic of this change. -- jlc */ | |
2058 | /* don't stop on /dev/console */ | |
01a5e440 PH |
2059 | if (file->f_op->write == redirected_tty_write || |
2060 | current->signal->tty != tty) | |
2061 | return 0; | |
2062 | ||
2063 | spin_lock_irq(&tty->ctrl_lock); | |
2064 | if (!tty->pgrp) | |
2065 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
2066 | else if (task_pgrp(current) != tty->pgrp) { | |
2067 | spin_unlock_irq(&tty->ctrl_lock); | |
2068 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
2069 | return -EIO; | |
2070 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
2071 | set_thread_flag(TIF_SIGPENDING); | |
2072 | return -ERESTARTSYS; | |
1da177e4 | 2073 | } |
01a5e440 | 2074 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
2075 | return 0; |
2076 | } | |
4edf1827 | 2077 | |
1da177e4 LT |
2078 | |
2079 | /** | |
11a96d18 | 2080 | * n_tty_read - read function for tty |
1da177e4 LT |
2081 | * @tty: tty device |
2082 | * @file: file object | |
2083 | * @buf: userspace buffer pointer | |
2084 | * @nr: size of I/O | |
2085 | * | |
2086 | * Perform reads for the line discipline. We are guaranteed that the | |
2087 | * line discipline will not be closed under us but we may get multiple | |
2088 | * parallel readers and must handle this ourselves. We may also get | |
2089 | * a hangup. Always called in user context, may sleep. | |
2090 | * | |
2091 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
2092 | * |
2093 | * n_tty_read()/consumer path: | |
2094 | * claims non-exclusive termios_rwsem | |
2095 | * publishes read_tail | |
1da177e4 | 2096 | */ |
4edf1827 | 2097 | |
11a96d18 | 2098 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
2099 | unsigned char __user *buf, size_t nr) |
2100 | { | |
53c5ee2c | 2101 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2102 | unsigned char __user *b = buf; |
2103 | DECLARE_WAITQUEUE(wait, current); | |
2104 | int c; | |
2105 | int minimum, time; | |
2106 | ssize_t retval = 0; | |
1da177e4 LT |
2107 | long timeout; |
2108 | unsigned long flags; | |
04f378b1 | 2109 | int packet; |
1da177e4 | 2110 | |
1da177e4 | 2111 | c = job_control(tty, file); |
4edf1827 | 2112 | if (c < 0) |
1da177e4 | 2113 | return c; |
4edf1827 | 2114 | |
9356b535 PH |
2115 | down_read(&tty->termios_rwsem); |
2116 | ||
1da177e4 LT |
2117 | minimum = time = 0; |
2118 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2119 | if (!ldata->icanon) { |
1da177e4 LT |
2120 | minimum = MIN_CHAR(tty); |
2121 | if (minimum) { | |
a6e54319 | 2122 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2123 | if (time) |
f6c8dbe6 | 2124 | ldata->minimum_to_wake = 1; |
1da177e4 | 2125 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
2126 | (ldata->minimum_to_wake > minimum)) |
2127 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 2128 | } else { |
a6e54319 | 2129 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 2130 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
2131 | } |
2132 | } | |
2133 | ||
2134 | /* | |
2135 | * Internal serialization of reads. | |
2136 | */ | |
2137 | if (file->f_flags & O_NONBLOCK) { | |
9356b535 PH |
2138 | if (!mutex_trylock(&ldata->atomic_read_lock)) { |
2139 | up_read(&tty->termios_rwsem); | |
1da177e4 | 2140 | return -EAGAIN; |
9356b535 | 2141 | } |
4edf1827 | 2142 | } else { |
9356b535 PH |
2143 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) { |
2144 | up_read(&tty->termios_rwsem); | |
1da177e4 | 2145 | return -ERESTARTSYS; |
9356b535 | 2146 | } |
1da177e4 | 2147 | } |
04f378b1 | 2148 | packet = tty->packet; |
1da177e4 LT |
2149 | |
2150 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2151 | while (nr) { |
2152 | /* First test for status change. */ | |
04f378b1 | 2153 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
2154 | unsigned char cs; |
2155 | if (b != buf) | |
2156 | break; | |
04f378b1 | 2157 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
2158 | cs = tty->link->ctrl_status; |
2159 | tty->link->ctrl_status = 0; | |
04f378b1 | 2160 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 2161 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
2162 | retval = -EFAULT; |
2163 | b--; | |
2164 | break; | |
2165 | } | |
2166 | nr--; | |
2167 | break; | |
2168 | } | |
2169 | /* This statement must be first before checking for input | |
2170 | so that any interrupt will set the state back to | |
2171 | TASK_RUNNING. */ | |
2172 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 2173 | |
f6c8dbe6 | 2174 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2175 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2176 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2177 | |
1da177e4 LT |
2178 | if (!input_available_p(tty, 0)) { |
2179 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
2180 | retval = -EIO; | |
2181 | break; | |
2182 | } | |
2183 | if (tty_hung_up_p(file)) | |
2184 | break; | |
2185 | if (!timeout) | |
2186 | break; | |
2187 | if (file->f_flags & O_NONBLOCK) { | |
2188 | retval = -EAGAIN; | |
2189 | break; | |
2190 | } | |
2191 | if (signal_pending(current)) { | |
2192 | retval = -ERESTARTSYS; | |
2193 | break; | |
2194 | } | |
55db4c64 | 2195 | n_tty_set_room(tty); |
9356b535 PH |
2196 | up_read(&tty->termios_rwsem); |
2197 | ||
1da177e4 | 2198 | timeout = schedule_timeout(timeout); |
9356b535 PH |
2199 | |
2200 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2201 | continue; |
2202 | } | |
2203 | __set_current_state(TASK_RUNNING); | |
2204 | ||
2205 | /* Deal with packet mode. */ | |
04f378b1 | 2206 | if (packet && b == buf) { |
522ed776 | 2207 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
2208 | retval = -EFAULT; |
2209 | b--; | |
2210 | break; | |
2211 | } | |
2212 | nr--; | |
2213 | } | |
2214 | ||
53c5ee2c | 2215 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2216 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
40d5e090 PH |
2217 | if (retval == -EAGAIN) { |
2218 | retval = 0; | |
2219 | continue; | |
2220 | } else if (retval) | |
1da177e4 LT |
2221 | break; |
2222 | } else { | |
2223 | int uncopied; | |
04f378b1 AC |
2224 | /* The copy function takes the read lock and handles |
2225 | locking internally for this case */ | |
1da177e4 LT |
2226 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2227 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2228 | if (uncopied) { | |
2229 | retval = -EFAULT; | |
2230 | break; | |
2231 | } | |
2232 | } | |
2233 | ||
6367ca72 | 2234 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2235 | |
2236 | if (b - buf >= minimum) | |
2237 | break; | |
2238 | if (time) | |
2239 | timeout = time; | |
2240 | } | |
bddc7152 | 2241 | mutex_unlock(&ldata->atomic_read_lock); |
1da177e4 LT |
2242 | remove_wait_queue(&tty->read_wait, &wait); |
2243 | ||
2244 | if (!waitqueue_active(&tty->read_wait)) | |
f6c8dbe6 | 2245 | ldata->minimum_to_wake = minimum; |
1da177e4 LT |
2246 | |
2247 | __set_current_state(TASK_RUNNING); | |
40d5e090 PH |
2248 | if (b - buf) |
2249 | retval = b - buf; | |
1da177e4 | 2250 | |
55db4c64 | 2251 | n_tty_set_room(tty); |
9356b535 | 2252 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2253 | return retval; |
2254 | } | |
2255 | ||
2256 | /** | |
11a96d18 | 2257 | * n_tty_write - write function for tty |
1da177e4 LT |
2258 | * @tty: tty device |
2259 | * @file: file object | |
2260 | * @buf: userspace buffer pointer | |
2261 | * @nr: size of I/O | |
2262 | * | |
a88a69c9 | 2263 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2264 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2265 | * and other such events. Since the receive code will echo characters, |
2266 | * thus calling driver write methods, the output_lock is used in | |
2267 | * the output processing functions called here as well as in the | |
2268 | * echo processing function to protect the column state and space | |
2269 | * left in the buffer. | |
1da177e4 LT |
2270 | * |
2271 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2272 | * |
2273 | * Locking: output_lock to protect column state and space left | |
2274 | * (note that the process_output*() functions take this | |
2275 | * lock themselves) | |
1da177e4 | 2276 | */ |
4edf1827 | 2277 | |
11a96d18 | 2278 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2279 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2280 | { |
2281 | const unsigned char *b = buf; | |
2282 | DECLARE_WAITQUEUE(wait, current); | |
2283 | int c; | |
2284 | ssize_t retval = 0; | |
2285 | ||
2286 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2287 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2288 | retval = tty_check_change(tty); | |
2289 | if (retval) | |
2290 | return retval; | |
2291 | } | |
2292 | ||
9356b535 PH |
2293 | down_read(&tty->termios_rwsem); |
2294 | ||
a88a69c9 JP |
2295 | /* Write out any echoed characters that are still pending */ |
2296 | process_echoes(tty); | |
300a6204 | 2297 | |
1da177e4 LT |
2298 | add_wait_queue(&tty->write_wait, &wait); |
2299 | while (1) { | |
2300 | set_current_state(TASK_INTERRUPTIBLE); | |
2301 | if (signal_pending(current)) { | |
2302 | retval = -ERESTARTSYS; | |
2303 | break; | |
2304 | } | |
2305 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2306 | retval = -EIO; | |
2307 | break; | |
2308 | } | |
582f5590 | 2309 | if (O_OPOST(tty)) { |
1da177e4 | 2310 | while (nr > 0) { |
a88a69c9 | 2311 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2312 | if (num < 0) { |
2313 | if (num == -EAGAIN) | |
2314 | break; | |
2315 | retval = num; | |
2316 | goto break_out; | |
2317 | } | |
2318 | b += num; | |
2319 | nr -= num; | |
2320 | if (nr == 0) | |
2321 | break; | |
2322 | c = *b; | |
a88a69c9 | 2323 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2324 | break; |
2325 | b++; nr--; | |
2326 | } | |
f34d7a5b AC |
2327 | if (tty->ops->flush_chars) |
2328 | tty->ops->flush_chars(tty); | |
1da177e4 | 2329 | } else { |
d6afe27b | 2330 | while (nr > 0) { |
f34d7a5b | 2331 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
2332 | if (c < 0) { |
2333 | retval = c; | |
2334 | goto break_out; | |
2335 | } | |
2336 | if (!c) | |
2337 | break; | |
2338 | b += c; | |
2339 | nr -= c; | |
1da177e4 | 2340 | } |
1da177e4 LT |
2341 | } |
2342 | if (!nr) | |
2343 | break; | |
2344 | if (file->f_flags & O_NONBLOCK) { | |
2345 | retval = -EAGAIN; | |
2346 | break; | |
2347 | } | |
9356b535 PH |
2348 | up_read(&tty->termios_rwsem); |
2349 | ||
1da177e4 | 2350 | schedule(); |
9356b535 PH |
2351 | |
2352 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2353 | } |
2354 | break_out: | |
2355 | __set_current_state(TASK_RUNNING); | |
2356 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2357 | if (b - buf != nr && tty->fasync) |
2358 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2359 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2360 | return (b - buf) ? b - buf : retval; |
2361 | } | |
2362 | ||
2363 | /** | |
11a96d18 | 2364 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2365 | * @tty: terminal device |
2366 | * @file: file accessing it | |
2367 | * @wait: poll table | |
2368 | * | |
2369 | * Called when the line discipline is asked to poll() for data or | |
2370 | * for special events. This code is not serialized with respect to | |
2371 | * other events save open/close. | |
2372 | * | |
2373 | * This code must be sure never to sleep through a hangup. | |
2374 | * Called without the kernel lock held - fine | |
1da177e4 | 2375 | */ |
4edf1827 | 2376 | |
11a96d18 | 2377 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2378 | poll_table *wait) |
1da177e4 | 2379 | { |
f6c8dbe6 | 2380 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2381 | unsigned int mask = 0; |
2382 | ||
2383 | poll_wait(file, &tty->read_wait, wait); | |
2384 | poll_wait(file, &tty->write_wait, wait); | |
2385 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2386 | mask |= POLLIN | POLLRDNORM; | |
2387 | if (tty->packet && tty->link->ctrl_status) | |
2388 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2389 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2390 | mask |= POLLHUP; | |
2391 | if (tty_hung_up_p(file)) | |
2392 | mask |= POLLHUP; | |
2393 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2394 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2395 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2396 | else |
f6c8dbe6 | 2397 | ldata->minimum_to_wake = 1; |
1da177e4 | 2398 | } |
f34d7a5b AC |
2399 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2400 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2401 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2402 | mask |= POLLOUT | POLLWRNORM; |
2403 | return mask; | |
2404 | } | |
2405 | ||
57c94121 | 2406 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2407 | { |
bc5a5e3f | 2408 | size_t nr, head, tail; |
47afa7a5 | 2409 | |
a73d3d69 | 2410 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2411 | return 0; |
ba2e68ac JS |
2412 | head = ldata->canon_head; |
2413 | tail = ldata->read_tail; | |
bc5a5e3f | 2414 | nr = head - tail; |
47afa7a5 AC |
2415 | /* Skip EOF-chars.. */ |
2416 | while (head != tail) { | |
bc5a5e3f PH |
2417 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2418 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2419 | nr--; |
bc5a5e3f | 2420 | tail++; |
47afa7a5 AC |
2421 | } |
2422 | return nr; | |
2423 | } | |
2424 | ||
2425 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2426 | unsigned int cmd, unsigned long arg) | |
2427 | { | |
ba2e68ac | 2428 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2429 | int retval; |
2430 | ||
2431 | switch (cmd) { | |
2432 | case TIOCOUTQ: | |
2433 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2434 | case TIOCINQ: | |
6d76bd26 | 2435 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2436 | if (L_ICANON(tty)) |
57c94121 | 2437 | retval = inq_canon(ldata); |
6d76bd26 PH |
2438 | else |
2439 | retval = read_cnt(ldata); | |
2440 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2441 | return put_user(retval, (unsigned int __user *) arg); |
2442 | default: | |
2443 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2444 | } | |
2445 | } | |
2446 | ||
f6c8dbe6 PH |
2447 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2448 | { | |
2449 | struct n_tty_data *ldata = tty->disc_data; | |
2450 | ||
2451 | if (!waitqueue_active(&tty->read_wait)) { | |
2452 | if (on) | |
2453 | ldata->minimum_to_wake = 1; | |
2454 | else if (!tty->fasync) | |
2455 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2456 | } | |
2457 | } | |
2458 | ||
a352def2 | 2459 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2460 | .magic = TTY_LDISC_MAGIC, |
2461 | .name = "n_tty", | |
2462 | .open = n_tty_open, | |
2463 | .close = n_tty_close, | |
2464 | .flush_buffer = n_tty_flush_buffer, | |
2465 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2466 | .read = n_tty_read, |
2467 | .write = n_tty_write, | |
e10cc1df PF |
2468 | .ioctl = n_tty_ioctl, |
2469 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2470 | .poll = n_tty_poll, |
e10cc1df | 2471 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2472 | .write_wakeup = n_tty_write_wakeup, |
2473 | .fasync = n_tty_fasync, | |
24a89d1c | 2474 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2475 | }; |
572b9adb RG |
2476 | |
2477 | /** | |
2478 | * n_tty_inherit_ops - inherit N_TTY methods | |
2479 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2480 | * | |
593fb1ae | 2481 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2482 | * methods. |
2483 | */ | |
2484 | ||
2485 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2486 | { | |
2487 | *ops = tty_ldisc_N_TTY; | |
2488 | ops->owner = NULL; | |
2489 | ops->refcount = ops->flags = 0; | |
2490 | } | |
2491 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |