Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * n_tty.c --- implements the N_TTY line discipline. | |
4edf1827 | 3 | * |
1da177e4 LT |
4 | * This code used to be in tty_io.c, but things are getting hairy |
5 | * enough that it made sense to split things off. (The N_TTY | |
6 | * processing has changed so much that it's hardly recognizable, | |
7 | * anyway...) | |
8 | * | |
9 | * Note that the open routine for N_TTY is guaranteed never to return | |
10 | * an error. This is because Linux will fall back to setting a line | |
4edf1827 | 11 | * to N_TTY if it can not switch to any other line discipline. |
1da177e4 LT |
12 | * |
13 | * Written by Theodore Ts'o, Copyright 1994. | |
4edf1827 | 14 | * |
1da177e4 LT |
15 | * This file also contains code originally written by Linus Torvalds, |
16 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. | |
4edf1827 | 17 | * |
1da177e4 LT |
18 | * This file may be redistributed under the terms of the GNU General Public |
19 | * License. | |
20 | * | |
21 | * Reduced memory usage for older ARM systems - Russell King. | |
22 | * | |
4edf1827 | 23 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
1da177e4 LT |
24 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
25 | * who actually finally proved there really was a race. | |
26 | * | |
27 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to | |
28 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. | |
11a96d18 | 29 | * Also fixed a bug in BLOCKING mode where n_tty_write returns |
1da177e4 LT |
30 | * EAGAIN |
31 | */ | |
32 | ||
33 | #include <linux/types.h> | |
34 | #include <linux/major.h> | |
35 | #include <linux/errno.h> | |
36 | #include <linux/signal.h> | |
37 | #include <linux/fcntl.h> | |
38 | #include <linux/sched.h> | |
39 | #include <linux/interrupt.h> | |
40 | #include <linux/tty.h> | |
41 | #include <linux/timer.h> | |
42 | #include <linux/ctype.h> | |
43 | #include <linux/mm.h> | |
44 | #include <linux/string.h> | |
45 | #include <linux/slab.h> | |
46 | #include <linux/poll.h> | |
47 | #include <linux/bitops.h> | |
522ed776 MT |
48 | #include <linux/audit.h> |
49 | #include <linux/file.h> | |
300a6204 | 50 | #include <linux/uaccess.h> |
572b9adb | 51 | #include <linux/module.h> |
593fb1ae | 52 | #include <linux/ratelimit.h> |
1da177e4 | 53 | |
1da177e4 LT |
54 | |
55 | /* number of characters left in xmit buffer before select has we have room */ | |
56 | #define WAKEUP_CHARS 256 | |
57 | ||
58 | /* | |
59 | * This defines the low- and high-watermarks for throttling and | |
60 | * unthrottling the TTY driver. These watermarks are used for | |
61 | * controlling the space in the read buffer. | |
62 | */ | |
63 | #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ | |
bbd20759 | 64 | #define TTY_THRESHOLD_UNTHROTTLE 128 |
1da177e4 | 65 | |
a88a69c9 JP |
66 | /* |
67 | * Special byte codes used in the echo buffer to represent operations | |
68 | * or special handling of characters. Bytes in the echo buffer that | |
69 | * are not part of such special blocks are treated as normal character | |
70 | * codes. | |
71 | */ | |
72 | #define ECHO_OP_START 0xff | |
73 | #define ECHO_OP_MOVE_BACK_COL 0x80 | |
74 | #define ECHO_OP_SET_CANON_COL 0x81 | |
75 | #define ECHO_OP_ERASE_TAB 0x82 | |
76 | ||
32f13521 PH |
77 | #undef N_TTY_TRACE |
78 | #ifdef N_TTY_TRACE | |
79 | # define n_tty_trace(f, args...) trace_printk(f, ##args) | |
80 | #else | |
81 | # define n_tty_trace(f, args...) | |
82 | #endif | |
83 | ||
70ece7a7 | 84 | struct n_tty_data { |
fb7aa03d PH |
85 | /* producer-published */ |
86 | size_t read_head; | |
87 | size_t canon_head; | |
88 | DECLARE_BITMAP(process_char_map, 256); | |
89 | ||
90 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c JS |
91 | unsigned long overrun_time; |
92 | int num_overrun; | |
93 | ||
24a89d1c PH |
94 | /* non-atomic */ |
95 | bool no_room; | |
96 | ||
fb7aa03d | 97 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c | 98 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
3fe780b3 | 99 | |
fb7aa03d PH |
100 | /* shared by producer and consumer */ |
101 | char *read_buf; | |
3fe780b3 | 102 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
ba2e68ac | 103 | |
f6c8dbe6 | 104 | int minimum_to_wake; |
ba2e68ac | 105 | |
fb7aa03d PH |
106 | /* consumer-published */ |
107 | size_t read_tail; | |
108 | ||
ba2e68ac | 109 | unsigned char *echo_buf; |
addaebcc PH |
110 | size_t echo_head; |
111 | size_t echo_tail; | |
17bd7907 | 112 | size_t echo_commit; |
ba2e68ac | 113 | |
fb7aa03d PH |
114 | /* protected by output lock */ |
115 | unsigned int column; | |
ba2e68ac | 116 | unsigned int canon_column; |
bddc7152 JS |
117 | |
118 | struct mutex atomic_read_lock; | |
119 | struct mutex output_lock; | |
70ece7a7 JS |
120 | }; |
121 | ||
ce74117a PH |
122 | static inline size_t read_cnt(struct n_tty_data *ldata) |
123 | { | |
a2f73be8 | 124 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
125 | } |
126 | ||
bc5a5e3f PH |
127 | static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) |
128 | { | |
129 | return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
130 | } | |
131 | ||
132 | static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) | |
133 | { | |
134 | return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
135 | } | |
136 | ||
addaebcc PH |
137 | static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) |
138 | { | |
139 | return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
140 | } | |
141 | ||
142 | static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) | |
143 | { | |
144 | return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; | |
145 | } | |
146 | ||
522ed776 MT |
147 | static inline int tty_put_user(struct tty_struct *tty, unsigned char x, |
148 | unsigned char __user *ptr) | |
149 | { | |
53c5ee2c JS |
150 | struct n_tty_data *ldata = tty->disc_data; |
151 | ||
152 | tty_audit_add_data(tty, &x, 1, ldata->icanon); | |
522ed776 MT |
153 | return put_user(x, ptr); |
154 | } | |
155 | ||
24a89d1c | 156 | static int receive_room(struct tty_struct *tty) |
55db4c64 | 157 | { |
53c5ee2c | 158 | struct n_tty_data *ldata = tty->disc_data; |
090abf7b | 159 | int left; |
55db4c64 | 160 | |
090abf7b JA |
161 | if (I_PARMRK(tty)) { |
162 | /* Multiply read_cnt by 3, since each byte might take up to | |
163 | * three times as many spaces when PARMRK is set (depending on | |
164 | * its flags, e.g. parity error). */ | |
ce74117a | 165 | left = N_TTY_BUF_SIZE - read_cnt(ldata) * 3 - 1; |
090abf7b | 166 | } else |
ce74117a | 167 | left = N_TTY_BUF_SIZE - read_cnt(ldata) - 1; |
090abf7b | 168 | |
55db4c64 LT |
169 | /* |
170 | * If we are doing input canonicalization, and there are no | |
171 | * pending newlines, let characters through without limit, so | |
172 | * that erase characters will be handled. Other excess | |
173 | * characters will be beeped. | |
174 | */ | |
175 | if (left <= 0) | |
a73d3d69 | 176 | left = ldata->icanon && ldata->canon_head == ldata->read_tail; |
55db4c64 | 177 | |
24a89d1c | 178 | return left; |
7879a9f9 PH |
179 | } |
180 | ||
24a89d1c PH |
181 | /** |
182 | * n_tty_set_room - receive space | |
183 | * @tty: terminal | |
184 | * | |
185 | * Re-schedules the flip buffer work if space just became available. | |
186 | * | |
6d76bd26 PH |
187 | * Caller holds exclusive termios_rwsem |
188 | * or | |
189 | * n_tty_read()/consumer path: | |
190 | * holds non-exclusive termios_rwsem | |
24a89d1c PH |
191 | */ |
192 | ||
7879a9f9 PH |
193 | static void n_tty_set_room(struct tty_struct *tty) |
194 | { | |
24a89d1c PH |
195 | struct n_tty_data *ldata = tty->disc_data; |
196 | ||
55db4c64 | 197 | /* Did this open up the receive buffer? We may need to flip */ |
24a89d1c PH |
198 | if (unlikely(ldata->no_room) && receive_room(tty)) { |
199 | ldata->no_room = 0; | |
200 | ||
ecbbfd44 | 201 | WARN_RATELIMIT(tty->port->itty == NULL, |
cadf7486 | 202 | "scheduling with invalid itty\n"); |
21622939 PH |
203 | /* see if ldisc has been killed - if so, this means that |
204 | * even though the ldisc has been halted and ->buf.work | |
205 | * cancelled, ->buf.work is about to be rescheduled | |
206 | */ | |
207 | WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), | |
208 | "scheduling buffer work for halted ldisc\n"); | |
f0f947c1 | 209 | queue_work(system_unbound_wq, &tty->port->buf.work); |
ecbbfd44 | 210 | } |
55db4c64 LT |
211 | } |
212 | ||
9a4aec2d PH |
213 | static ssize_t chars_in_buffer(struct tty_struct *tty) |
214 | { | |
215 | struct n_tty_data *ldata = tty->disc_data; | |
216 | ssize_t n = 0; | |
217 | ||
218 | if (!ldata->icanon) | |
219 | n = read_cnt(ldata); | |
220 | else | |
221 | n = ldata->canon_head - ldata->read_tail; | |
222 | return n; | |
223 | } | |
224 | ||
ee0bab83 PH |
225 | /** |
226 | * n_tty_write_wakeup - asynchronous I/O notifier | |
227 | * @tty: tty device | |
228 | * | |
229 | * Required for the ptys, serial driver etc. since processes | |
230 | * that attach themselves to the master and rely on ASYNC | |
231 | * IO must be woken up | |
232 | */ | |
233 | ||
234 | static void n_tty_write_wakeup(struct tty_struct *tty) | |
235 | { | |
236 | if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) | |
237 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
238 | } | |
239 | ||
6367ca72 PH |
240 | static inline void n_tty_check_throttle(struct tty_struct *tty) |
241 | { | |
3afb1b39 PH |
242 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) |
243 | return; | |
6367ca72 PH |
244 | /* |
245 | * Check the remaining room for the input canonicalization | |
246 | * mode. We don't want to throttle the driver if we're in | |
247 | * canonical mode and don't have a newline yet! | |
248 | */ | |
249 | while (1) { | |
250 | int throttled; | |
251 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); | |
252 | if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) | |
253 | break; | |
254 | throttled = tty_throttle_safe(tty); | |
255 | if (!throttled) | |
256 | break; | |
257 | } | |
258 | __tty_set_flow_change(tty, 0); | |
259 | } | |
260 | ||
261 | static inline void n_tty_check_unthrottle(struct tty_struct *tty) | |
262 | { | |
3afb1b39 PH |
263 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
264 | tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { | |
265 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
266 | return; | |
267 | if (!tty->count) | |
268 | return; | |
269 | n_tty_set_room(tty); | |
270 | n_tty_write_wakeup(tty->link); | |
271 | wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); | |
272 | return; | |
273 | } | |
274 | ||
6367ca72 PH |
275 | /* If there is enough space in the read buffer now, let the |
276 | * low-level driver know. We use chars_in_buffer() to | |
277 | * check the buffer, as it now knows about canonical mode. | |
278 | * Otherwise, if the driver is throttled and the line is | |
279 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
280 | * we won't get any more characters. | |
281 | */ | |
282 | ||
283 | while (1) { | |
284 | int unthrottled; | |
285 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
286 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
287 | break; | |
288 | if (!tty->count) | |
289 | break; | |
290 | n_tty_set_room(tty); | |
291 | unthrottled = tty_unthrottle_safe(tty); | |
292 | if (!unthrottled) | |
293 | break; | |
294 | } | |
295 | __tty_set_flow_change(tty, 0); | |
296 | } | |
297 | ||
17b82060 AC |
298 | /** |
299 | * put_tty_queue - add character to tty | |
300 | * @c: character | |
57c94121 | 301 | * @ldata: n_tty data |
17b82060 | 302 | * |
6d76bd26 PH |
303 | * Add a character to the tty read_buf queue. |
304 | * | |
305 | * n_tty_receive_buf()/producer path: | |
306 | * caller holds non-exclusive termios_rwsem | |
307 | * modifies read_head | |
308 | * | |
309 | * read_head is only considered 'published' if canonical mode is | |
310 | * not active. | |
17b82060 AC |
311 | */ |
312 | ||
57c94121 | 313 | static void put_tty_queue(unsigned char c, struct n_tty_data *ldata) |
1da177e4 | 314 | { |
6d76bd26 PH |
315 | if (read_cnt(ldata) < N_TTY_BUF_SIZE) { |
316 | *read_buf_addr(ldata, ldata->read_head) = c; | |
317 | ldata->read_head++; | |
318 | } | |
1da177e4 LT |
319 | } |
320 | ||
1da177e4 LT |
321 | /** |
322 | * reset_buffer_flags - reset buffer state | |
323 | * @tty: terminal to reset | |
324 | * | |
25518c68 PH |
325 | * Reset the read buffer counters and clear the flags. |
326 | * Called from n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 327 | * |
6d76bd26 PH |
328 | * Locking: caller holds exclusive termios_rwsem |
329 | * (or locking is not required) | |
1da177e4 | 330 | */ |
a88a69c9 | 331 | |
b66f4fa5 | 332 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 333 | { |
a73d3d69 | 334 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
17bd7907 | 335 | ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; |
a88a69c9 | 336 | |
a73d3d69 | 337 | ldata->erasing = 0; |
3fe780b3 | 338 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
1da177e4 LT |
339 | } |
340 | ||
a30737ab PH |
341 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
342 | { | |
343 | unsigned long flags; | |
344 | ||
345 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
346 | if (tty->link->packet) { | |
347 | tty->ctrl_status |= TIOCPKT_FLUSHREAD; | |
348 | wake_up_interruptible(&tty->link->read_wait); | |
349 | } | |
350 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
351 | } | |
352 | ||
1da177e4 LT |
353 | /** |
354 | * n_tty_flush_buffer - clean input queue | |
355 | * @tty: terminal device | |
356 | * | |
25518c68 PH |
357 | * Flush the input buffer. Called when the tty layer wants the |
358 | * buffer flushed (eg at hangup) or when the N_TTY line discipline | |
359 | * internally has to clean the pending queue (for example some signals). | |
1da177e4 | 360 | * |
6d76bd26 PH |
361 | * Holds termios_rwsem to exclude producer/consumer while |
362 | * buffer indices are reset. | |
363 | * | |
364 | * Locking: ctrl_lock, exclusive termios_rwsem | |
1da177e4 | 365 | */ |
4edf1827 AC |
366 | |
367 | static void n_tty_flush_buffer(struct tty_struct *tty) | |
1da177e4 | 368 | { |
6d76bd26 | 369 | down_write(&tty->termios_rwsem); |
b66f4fa5 PH |
370 | reset_buffer_flags(tty->disc_data); |
371 | n_tty_set_room(tty); | |
4edf1827 | 372 | |
a30737ab PH |
373 | if (tty->link) |
374 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 375 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
376 | } |
377 | ||
6d76bd26 PH |
378 | /** |
379 | * n_tty_chars_in_buffer - report available bytes | |
380 | * @tty: tty device | |
381 | * | |
382 | * Report the number of characters buffered to be delivered to user | |
383 | * at this instant in time. | |
384 | * | |
385 | * Locking: exclusive termios_rwsem | |
386 | */ | |
387 | ||
a19d0c6a PH |
388 | static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) |
389 | { | |
6d76bd26 PH |
390 | ssize_t n; |
391 | ||
47534084 | 392 | WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); |
6d76bd26 PH |
393 | |
394 | down_write(&tty->termios_rwsem); | |
395 | n = chars_in_buffer(tty); | |
396 | up_write(&tty->termios_rwsem); | |
397 | return n; | |
a19d0c6a PH |
398 | } |
399 | ||
1da177e4 LT |
400 | /** |
401 | * is_utf8_continuation - utf8 multibyte check | |
402 | * @c: byte to check | |
403 | * | |
404 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
405 | * character. We use this to correctly compute the on screen size | |
406 | * of the character when printing | |
407 | */ | |
4edf1827 | 408 | |
1da177e4 LT |
409 | static inline int is_utf8_continuation(unsigned char c) |
410 | { | |
411 | return (c & 0xc0) == 0x80; | |
412 | } | |
413 | ||
414 | /** | |
415 | * is_continuation - multibyte check | |
416 | * @c: byte to check | |
417 | * | |
418 | * Returns true if the utf8 character 'c' is a multibyte continuation | |
419 | * character and the terminal is in unicode mode. | |
420 | */ | |
4edf1827 | 421 | |
1da177e4 LT |
422 | static inline int is_continuation(unsigned char c, struct tty_struct *tty) |
423 | { | |
424 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
425 | } | |
426 | ||
427 | /** | |
a88a69c9 | 428 | * do_output_char - output one character |
1da177e4 LT |
429 | * @c: character (or partial unicode symbol) |
430 | * @tty: terminal device | |
a88a69c9 | 431 | * @space: space available in tty driver write buffer |
1da177e4 | 432 | * |
a88a69c9 JP |
433 | * This is a helper function that handles one output character |
434 | * (including special characters like TAB, CR, LF, etc.), | |
ee5aa7b8 JP |
435 | * doing OPOST processing and putting the results in the |
436 | * tty driver's write buffer. | |
a88a69c9 JP |
437 | * |
438 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY | |
439 | * and NLDLY. They simply aren't relevant in the world today. | |
440 | * If you ever need them, add them here. | |
1da177e4 | 441 | * |
a88a69c9 JP |
442 | * Returns the number of bytes of buffer space used or -1 if |
443 | * no space left. | |
444 | * | |
445 | * Locking: should be called under the output_lock to protect | |
446 | * the column state and space left in the buffer | |
1da177e4 | 447 | */ |
4edf1827 | 448 | |
a88a69c9 | 449 | static int do_output_char(unsigned char c, struct tty_struct *tty, int space) |
1da177e4 | 450 | { |
53c5ee2c | 451 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 452 | int spaces; |
1da177e4 | 453 | |
1da177e4 LT |
454 | if (!space) |
455 | return -1; | |
300a6204 | 456 | |
a88a69c9 JP |
457 | switch (c) { |
458 | case '\n': | |
459 | if (O_ONLRET(tty)) | |
53c5ee2c | 460 | ldata->column = 0; |
a88a69c9 JP |
461 | if (O_ONLCR(tty)) { |
462 | if (space < 2) | |
463 | return -1; | |
ba2e68ac | 464 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 465 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
466 | return 2; |
467 | } | |
ba2e68ac | 468 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
469 | break; |
470 | case '\r': | |
53c5ee2c | 471 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
472 | return 0; |
473 | if (O_OCRNL(tty)) { | |
474 | c = '\n'; | |
475 | if (O_ONLRET(tty)) | |
ba2e68ac | 476 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 477 | break; |
a88a69c9 | 478 | } |
ba2e68ac | 479 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
480 | break; |
481 | case '\t': | |
53c5ee2c | 482 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
483 | if (O_TABDLY(tty) == XTABS) { |
484 | if (space < spaces) | |
485 | return -1; | |
53c5ee2c | 486 | ldata->column += spaces; |
a88a69c9 JP |
487 | tty->ops->write(tty, " ", spaces); |
488 | return spaces; | |
1da177e4 | 489 | } |
53c5ee2c | 490 | ldata->column += spaces; |
a88a69c9 JP |
491 | break; |
492 | case '\b': | |
53c5ee2c JS |
493 | if (ldata->column > 0) |
494 | ldata->column--; | |
a88a69c9 JP |
495 | break; |
496 | default: | |
a59c0d6f JP |
497 | if (!iscntrl(c)) { |
498 | if (O_OLCUC(tty)) | |
499 | c = toupper(c); | |
500 | if (!is_continuation(c, tty)) | |
53c5ee2c | 501 | ldata->column++; |
a59c0d6f | 502 | } |
a88a69c9 | 503 | break; |
1da177e4 | 504 | } |
a88a69c9 | 505 | |
f34d7a5b | 506 | tty_put_char(tty, c); |
a88a69c9 JP |
507 | return 1; |
508 | } | |
509 | ||
510 | /** | |
511 | * process_output - output post processor | |
512 | * @c: character (or partial unicode symbol) | |
513 | * @tty: terminal device | |
514 | * | |
ee5aa7b8 JP |
515 | * Output one character with OPOST processing. |
516 | * Returns -1 when the output device is full and the character | |
517 | * must be retried. | |
a88a69c9 JP |
518 | * |
519 | * Locking: output_lock to protect column state and space left | |
520 | * (also, this is called from n_tty_write under the | |
521 | * tty layer write lock) | |
522 | */ | |
523 | ||
524 | static int process_output(unsigned char c, struct tty_struct *tty) | |
525 | { | |
bddc7152 | 526 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
527 | int space, retval; |
528 | ||
bddc7152 | 529 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
530 | |
531 | space = tty_write_room(tty); | |
532 | retval = do_output_char(c, tty, space); | |
533 | ||
bddc7152 | 534 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
535 | if (retval < 0) |
536 | return -1; | |
537 | else | |
538 | return 0; | |
1da177e4 LT |
539 | } |
540 | ||
541 | /** | |
a88a69c9 | 542 | * process_output_block - block post processor |
1da177e4 | 543 | * @tty: terminal device |
ee5aa7b8 JP |
544 | * @buf: character buffer |
545 | * @nr: number of bytes to output | |
546 | * | |
547 | * Output a block of characters with OPOST processing. | |
548 | * Returns the number of characters output. | |
1da177e4 LT |
549 | * |
550 | * This path is used to speed up block console writes, among other | |
551 | * things when processing blocks of output data. It handles only | |
552 | * the simple cases normally found and helps to generate blocks of | |
553 | * symbols for the console driver and thus improve performance. | |
554 | * | |
a88a69c9 JP |
555 | * Locking: output_lock to protect column state and space left |
556 | * (also, this is called from n_tty_write under the | |
557 | * tty layer write lock) | |
1da177e4 | 558 | */ |
4edf1827 | 559 | |
a88a69c9 JP |
560 | static ssize_t process_output_block(struct tty_struct *tty, |
561 | const unsigned char *buf, unsigned int nr) | |
1da177e4 | 562 | { |
53c5ee2c | 563 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 564 | int space; |
bbd20759 | 565 | int i; |
1da177e4 LT |
566 | const unsigned char *cp; |
567 | ||
bddc7152 | 568 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 569 | |
f34d7a5b | 570 | space = tty_write_room(tty); |
300a6204 | 571 | if (!space) { |
bddc7152 | 572 | mutex_unlock(&ldata->output_lock); |
1da177e4 | 573 | return 0; |
a88a69c9 | 574 | } |
1da177e4 LT |
575 | if (nr > space) |
576 | nr = space; | |
577 | ||
578 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
a59c0d6f JP |
579 | unsigned char c = *cp; |
580 | ||
581 | switch (c) { | |
1da177e4 LT |
582 | case '\n': |
583 | if (O_ONLRET(tty)) | |
53c5ee2c | 584 | ldata->column = 0; |
1da177e4 LT |
585 | if (O_ONLCR(tty)) |
586 | goto break_out; | |
ba2e68ac | 587 | ldata->canon_column = ldata->column; |
1da177e4 LT |
588 | break; |
589 | case '\r': | |
53c5ee2c | 590 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
591 | goto break_out; |
592 | if (O_OCRNL(tty)) | |
593 | goto break_out; | |
ba2e68ac | 594 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
595 | break; |
596 | case '\t': | |
597 | goto break_out; | |
598 | case '\b': | |
53c5ee2c JS |
599 | if (ldata->column > 0) |
600 | ldata->column--; | |
1da177e4 LT |
601 | break; |
602 | default: | |
a59c0d6f JP |
603 | if (!iscntrl(c)) { |
604 | if (O_OLCUC(tty)) | |
605 | goto break_out; | |
606 | if (!is_continuation(c, tty)) | |
53c5ee2c | 607 | ldata->column++; |
a59c0d6f | 608 | } |
1da177e4 LT |
609 | break; |
610 | } | |
611 | } | |
612 | break_out: | |
f34d7a5b | 613 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 614 | |
bddc7152 | 615 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
616 | return i; |
617 | } | |
618 | ||
a88a69c9 JP |
619 | /** |
620 | * process_echoes - write pending echo characters | |
621 | * @tty: terminal device | |
622 | * | |
623 | * Write previously buffered echo (and other ldisc-generated) | |
624 | * characters to the tty. | |
625 | * | |
626 | * Characters generated by the ldisc (including echoes) need to | |
627 | * be buffered because the driver's write buffer can fill during | |
628 | * heavy program output. Echoing straight to the driver will | |
629 | * often fail under these conditions, causing lost characters and | |
630 | * resulting mismatches of ldisc state information. | |
631 | * | |
632 | * Since the ldisc state must represent the characters actually sent | |
633 | * to the driver at the time of the write, operations like certain | |
634 | * changes in column state are also saved in the buffer and executed | |
635 | * here. | |
636 | * | |
637 | * A circular fifo buffer is used so that the most recent characters | |
638 | * are prioritized. Also, when control characters are echoed with a | |
639 | * prefixed "^", the pair is treated atomically and thus not separated. | |
640 | * | |
17bd7907 | 641 | * Locking: output_lock to protect column state and space left |
a88a69c9 JP |
642 | */ |
643 | ||
644 | static void process_echoes(struct tty_struct *tty) | |
645 | { | |
53c5ee2c | 646 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 647 | int space, nr; |
addaebcc | 648 | size_t tail; |
a88a69c9 | 649 | unsigned char c; |
a88a69c9 | 650 | |
17bd7907 | 651 | if (ldata->echo_commit == ldata->echo_tail) |
a88a69c9 JP |
652 | return; |
653 | ||
bddc7152 | 654 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
655 | |
656 | space = tty_write_room(tty); | |
657 | ||
addaebcc | 658 | tail = ldata->echo_tail; |
17bd7907 | 659 | nr = ldata->echo_commit - ldata->echo_tail; |
a88a69c9 | 660 | while (nr > 0) { |
addaebcc | 661 | c = echo_buf(ldata, tail); |
a88a69c9 JP |
662 | if (c == ECHO_OP_START) { |
663 | unsigned char op; | |
a88a69c9 JP |
664 | int no_space_left = 0; |
665 | ||
666 | /* | |
667 | * If the buffer byte is the start of a multi-byte | |
668 | * operation, get the next byte, which is either the | |
669 | * op code or a control character value. | |
670 | */ | |
addaebcc | 671 | op = echo_buf(ldata, tail + 1); |
300a6204 | 672 | |
a88a69c9 JP |
673 | switch (op) { |
674 | unsigned int num_chars, num_bs; | |
675 | ||
676 | case ECHO_OP_ERASE_TAB: | |
addaebcc | 677 | num_chars = echo_buf(ldata, tail + 2); |
a88a69c9 JP |
678 | |
679 | /* | |
680 | * Determine how many columns to go back | |
681 | * in order to erase the tab. | |
682 | * This depends on the number of columns | |
683 | * used by other characters within the tab | |
684 | * area. If this (modulo 8) count is from | |
685 | * the start of input rather than from a | |
686 | * previous tab, we offset by canon column. | |
687 | * Otherwise, tab spacing is normal. | |
688 | */ | |
689 | if (!(num_chars & 0x80)) | |
ba2e68ac | 690 | num_chars += ldata->canon_column; |
a88a69c9 JP |
691 | num_bs = 8 - (num_chars & 7); |
692 | ||
693 | if (num_bs > space) { | |
694 | no_space_left = 1; | |
695 | break; | |
696 | } | |
697 | space -= num_bs; | |
698 | while (num_bs--) { | |
699 | tty_put_char(tty, '\b'); | |
53c5ee2c JS |
700 | if (ldata->column > 0) |
701 | ldata->column--; | |
a88a69c9 | 702 | } |
addaebcc | 703 | tail += 3; |
a88a69c9 JP |
704 | nr -= 3; |
705 | break; | |
706 | ||
707 | case ECHO_OP_SET_CANON_COL: | |
ba2e68ac | 708 | ldata->canon_column = ldata->column; |
addaebcc | 709 | tail += 2; |
a88a69c9 JP |
710 | nr -= 2; |
711 | break; | |
712 | ||
713 | case ECHO_OP_MOVE_BACK_COL: | |
53c5ee2c JS |
714 | if (ldata->column > 0) |
715 | ldata->column--; | |
addaebcc | 716 | tail += 2; |
a88a69c9 JP |
717 | nr -= 2; |
718 | break; | |
719 | ||
720 | case ECHO_OP_START: | |
721 | /* This is an escaped echo op start code */ | |
722 | if (!space) { | |
723 | no_space_left = 1; | |
724 | break; | |
725 | } | |
726 | tty_put_char(tty, ECHO_OP_START); | |
53c5ee2c | 727 | ldata->column++; |
a88a69c9 | 728 | space--; |
addaebcc | 729 | tail += 2; |
a88a69c9 JP |
730 | nr -= 2; |
731 | break; | |
732 | ||
733 | default: | |
a88a69c9 | 734 | /* |
62b26358 JP |
735 | * If the op is not a special byte code, |
736 | * it is a ctrl char tagged to be echoed | |
737 | * as "^X" (where X is the letter | |
738 | * representing the control char). | |
739 | * Note that we must ensure there is | |
740 | * enough space for the whole ctrl pair. | |
741 | * | |
a88a69c9 | 742 | */ |
62b26358 JP |
743 | if (space < 2) { |
744 | no_space_left = 1; | |
745 | break; | |
746 | } | |
747 | tty_put_char(tty, '^'); | |
748 | tty_put_char(tty, op ^ 0100); | |
53c5ee2c | 749 | ldata->column += 2; |
62b26358 | 750 | space -= 2; |
addaebcc | 751 | tail += 2; |
a88a69c9 JP |
752 | nr -= 2; |
753 | } | |
754 | ||
755 | if (no_space_left) | |
756 | break; | |
757 | } else { | |
582f5590 | 758 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
759 | int retval = do_output_char(c, tty, space); |
760 | if (retval < 0) | |
761 | break; | |
762 | space -= retval; | |
763 | } else { | |
764 | if (!space) | |
765 | break; | |
766 | tty_put_char(tty, c); | |
767 | space -= 1; | |
768 | } | |
addaebcc | 769 | tail += 1; |
a88a69c9 JP |
770 | nr -= 1; |
771 | } | |
a88a69c9 JP |
772 | } |
773 | ||
addaebcc | 774 | ldata->echo_tail = tail; |
a88a69c9 | 775 | |
bddc7152 | 776 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
777 | |
778 | if (tty->ops->flush_chars) | |
779 | tty->ops->flush_chars(tty); | |
780 | } | |
781 | ||
17bd7907 PH |
782 | static void commit_echoes(struct tty_struct *tty) |
783 | { | |
784 | struct n_tty_data *ldata = tty->disc_data; | |
785 | ||
786 | smp_mb(); | |
787 | ldata->echo_commit = ldata->echo_head; | |
788 | process_echoes(tty); | |
789 | } | |
790 | ||
a88a69c9 JP |
791 | /** |
792 | * add_echo_byte - add a byte to the echo buffer | |
793 | * @c: unicode byte to echo | |
57c94121 | 794 | * @ldata: n_tty data |
a88a69c9 JP |
795 | * |
796 | * Add a character or operation byte to the echo buffer. | |
797 | * | |
17bd7907 PH |
798 | * Locks: may claim output_lock to prevent concurrent modify of |
799 | * echo_tail by process_echoes(). | |
a88a69c9 JP |
800 | */ |
801 | ||
57c94121 | 802 | static void add_echo_byte(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 803 | { |
862eeffe | 804 | if (ldata->echo_head - ldata->echo_tail == N_TTY_BUF_SIZE) { |
addaebcc | 805 | size_t head = ldata->echo_head; |
17bd7907 PH |
806 | |
807 | mutex_lock(&ldata->output_lock); | |
a88a69c9 JP |
808 | /* |
809 | * Since the buffer start position needs to be advanced, | |
810 | * be sure to step by a whole operation byte group. | |
811 | */ | |
addaebcc | 812 | if (echo_buf(ldata, head) == ECHO_OP_START) { |
862eeffe | 813 | if (echo_buf(ldata, head + 1) == ECHO_OP_ERASE_TAB) |
addaebcc | 814 | ldata->echo_tail += 3; |
862eeffe | 815 | else |
addaebcc | 816 | ldata->echo_tail += 2; |
addaebcc PH |
817 | } else |
818 | ldata->echo_tail++; | |
17bd7907 | 819 | mutex_unlock(&ldata->output_lock); |
862eeffe | 820 | } |
a88a69c9 | 821 | |
addaebcc | 822 | *echo_buf_addr(ldata, ldata->echo_head++) = c; |
a88a69c9 JP |
823 | } |
824 | ||
825 | /** | |
826 | * echo_move_back_col - add operation to move back a column | |
57c94121 | 827 | * @ldata: n_tty data |
a88a69c9 JP |
828 | * |
829 | * Add an operation to the echo buffer to move back one column. | |
a88a69c9 JP |
830 | */ |
831 | ||
57c94121 | 832 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 833 | { |
57c94121 JS |
834 | add_echo_byte(ECHO_OP_START, ldata); |
835 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
836 | } |
837 | ||
838 | /** | |
839 | * echo_set_canon_col - add operation to set the canon column | |
57c94121 | 840 | * @ldata: n_tty data |
a88a69c9 JP |
841 | * |
842 | * Add an operation to the echo buffer to set the canon column | |
843 | * to the current column. | |
a88a69c9 JP |
844 | */ |
845 | ||
57c94121 | 846 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 847 | { |
57c94121 JS |
848 | add_echo_byte(ECHO_OP_START, ldata); |
849 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
850 | } |
851 | ||
852 | /** | |
853 | * echo_erase_tab - add operation to erase a tab | |
854 | * @num_chars: number of character columns already used | |
855 | * @after_tab: true if num_chars starts after a previous tab | |
57c94121 | 856 | * @ldata: n_tty data |
a88a69c9 JP |
857 | * |
858 | * Add an operation to the echo buffer to erase a tab. | |
859 | * | |
860 | * Called by the eraser function, which knows how many character | |
861 | * columns have been used since either a previous tab or the start | |
862 | * of input. This information will be used later, along with | |
863 | * canon column (if applicable), to go back the correct number | |
864 | * of columns. | |
a88a69c9 JP |
865 | */ |
866 | ||
867 | static void echo_erase_tab(unsigned int num_chars, int after_tab, | |
57c94121 | 868 | struct n_tty_data *ldata) |
a88a69c9 | 869 | { |
57c94121 JS |
870 | add_echo_byte(ECHO_OP_START, ldata); |
871 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
872 | |
873 | /* We only need to know this modulo 8 (tab spacing) */ | |
874 | num_chars &= 7; | |
875 | ||
876 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
877 | if (after_tab) | |
878 | num_chars |= 0x80; | |
300a6204 | 879 | |
57c94121 | 880 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
881 | } |
882 | ||
883 | /** | |
884 | * echo_char_raw - echo a character raw | |
885 | * @c: unicode byte to echo | |
886 | * @tty: terminal device | |
887 | * | |
888 | * Echo user input back onto the screen. This must be called only when | |
889 | * L_ECHO(tty) is true. Called from the driver receive_buf path. | |
890 | * | |
891 | * This variant does not treat control characters specially. | |
a88a69c9 JP |
892 | */ |
893 | ||
57c94121 | 894 | static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) |
a88a69c9 | 895 | { |
a88a69c9 | 896 | if (c == ECHO_OP_START) { |
57c94121 JS |
897 | add_echo_byte(ECHO_OP_START, ldata); |
898 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 899 | } else { |
57c94121 | 900 | add_echo_byte(c, ldata); |
a88a69c9 | 901 | } |
a88a69c9 | 902 | } |
1da177e4 | 903 | |
1da177e4 | 904 | /** |
a88a69c9 | 905 | * echo_char - echo a character |
1da177e4 LT |
906 | * @c: unicode byte to echo |
907 | * @tty: terminal device | |
908 | * | |
4edf1827 | 909 | * Echo user input back onto the screen. This must be called only when |
1da177e4 | 910 | * L_ECHO(tty) is true. Called from the driver receive_buf path. |
17b82060 | 911 | * |
62b26358 JP |
912 | * This variant tags control characters to be echoed as "^X" |
913 | * (where X is the letter representing the control char). | |
1da177e4 LT |
914 | */ |
915 | ||
916 | static void echo_char(unsigned char c, struct tty_struct *tty) | |
917 | { | |
bddc7152 JS |
918 | struct n_tty_data *ldata = tty->disc_data; |
919 | ||
a88a69c9 | 920 | if (c == ECHO_OP_START) { |
57c94121 JS |
921 | add_echo_byte(ECHO_OP_START, ldata); |
922 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 923 | } else { |
62b26358 | 924 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
925 | add_echo_byte(ECHO_OP_START, ldata); |
926 | add_echo_byte(c, ldata); | |
a88a69c9 | 927 | } |
1da177e4 LT |
928 | } |
929 | ||
17b82060 | 930 | /** |
a88a69c9 | 931 | * finish_erasing - complete erase |
57c94121 | 932 | * @ldata: n_tty data |
17b82060 | 933 | */ |
a88a69c9 | 934 | |
57c94121 | 935 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 936 | { |
53c5ee2c | 937 | if (ldata->erasing) { |
57c94121 | 938 | echo_char_raw('/', ldata); |
53c5ee2c | 939 | ldata->erasing = 0; |
1da177e4 LT |
940 | } |
941 | } | |
942 | ||
943 | /** | |
944 | * eraser - handle erase function | |
945 | * @c: character input | |
946 | * @tty: terminal device | |
947 | * | |
3a4fa0a2 | 948 | * Perform erase and necessary output when an erase character is |
1da177e4 LT |
949 | * present in the stream from the driver layer. Handles the complexities |
950 | * of UTF-8 multibyte symbols. | |
17b82060 | 951 | * |
6d76bd26 PH |
952 | * n_tty_receive_buf()/producer path: |
953 | * caller holds non-exclusive termios_rwsem | |
954 | * modifies read_head | |
955 | * | |
956 | * Modifying the read_head is not considered a publish in this context | |
957 | * because canonical mode is active -- only canon_head publishes | |
1da177e4 | 958 | */ |
4edf1827 | 959 | |
1da177e4 LT |
960 | static void eraser(unsigned char c, struct tty_struct *tty) |
961 | { | |
53c5ee2c | 962 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 963 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
964 | size_t head; |
965 | size_t cnt; | |
966 | int seen_alnums; | |
1da177e4 | 967 | |
ba2e68ac | 968 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 969 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
970 | return; |
971 | } | |
972 | if (c == ERASE_CHAR(tty)) | |
973 | kill_type = ERASE; | |
974 | else if (c == WERASE_CHAR(tty)) | |
975 | kill_type = WERASE; | |
976 | else { | |
977 | if (!L_ECHO(tty)) { | |
ba2e68ac | 978 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
979 | return; |
980 | } | |
981 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 982 | ldata->read_head = ldata->canon_head; |
57c94121 | 983 | finish_erasing(ldata); |
1da177e4 LT |
984 | echo_char(KILL_CHAR(tty), tty); |
985 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
986 | if (L_ECHOK(tty)) | |
57c94121 | 987 | echo_char_raw('\n', ldata); |
1da177e4 LT |
988 | return; |
989 | } | |
990 | kill_type = KILL; | |
991 | } | |
992 | ||
993 | seen_alnums = 0; | |
ba2e68ac JS |
994 | while (ldata->read_head != ldata->canon_head) { |
995 | head = ldata->read_head; | |
1da177e4 LT |
996 | |
997 | /* erase a single possibly multibyte character */ | |
998 | do { | |
bc5a5e3f PH |
999 | head--; |
1000 | c = read_buf(ldata, head); | |
ba2e68ac | 1001 | } while (is_continuation(c, tty) && head != ldata->canon_head); |
1da177e4 LT |
1002 | |
1003 | /* do not partially erase */ | |
1004 | if (is_continuation(c, tty)) | |
1005 | break; | |
1006 | ||
1007 | if (kill_type == WERASE) { | |
1008 | /* Equivalent to BSD's ALTWERASE. */ | |
1009 | if (isalnum(c) || c == '_') | |
1010 | seen_alnums++; | |
1011 | else if (seen_alnums) | |
1012 | break; | |
1013 | } | |
bc5a5e3f | 1014 | cnt = ldata->read_head - head; |
ba2e68ac | 1015 | ldata->read_head = head; |
1da177e4 LT |
1016 | if (L_ECHO(tty)) { |
1017 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1018 | if (!ldata->erasing) { |
57c94121 | 1019 | echo_char_raw('\\', ldata); |
53c5ee2c | 1020 | ldata->erasing = 1; |
1da177e4 LT |
1021 | } |
1022 | /* if cnt > 1, output a multi-byte character */ | |
1023 | echo_char(c, tty); | |
1024 | while (--cnt > 0) { | |
bc5a5e3f PH |
1025 | head++; |
1026 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1027 | echo_move_back_col(ldata); |
1da177e4 LT |
1028 | } |
1029 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1030 | echo_char(ERASE_CHAR(tty), tty); | |
1031 | } else if (c == '\t') { | |
a88a69c9 JP |
1032 | unsigned int num_chars = 0; |
1033 | int after_tab = 0; | |
bc5a5e3f | 1034 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1035 | |
1036 | /* | |
1037 | * Count the columns used for characters | |
1038 | * since the start of input or after a | |
1039 | * previous tab. | |
1040 | * This info is used to go back the correct | |
1041 | * number of columns. | |
1042 | */ | |
ba2e68ac | 1043 | while (tail != ldata->canon_head) { |
bc5a5e3f PH |
1044 | tail--; |
1045 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1046 | if (c == '\t') { |
1047 | after_tab = 1; | |
1048 | break; | |
300a6204 | 1049 | } else if (iscntrl(c)) { |
1da177e4 | 1050 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1051 | num_chars += 2; |
1052 | } else if (!is_continuation(c, tty)) { | |
1053 | num_chars++; | |
1054 | } | |
1da177e4 | 1055 | } |
57c94121 | 1056 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1057 | } else { |
1058 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1059 | echo_char_raw('\b', ldata); |
1060 | echo_char_raw(' ', ldata); | |
1061 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1062 | } |
1063 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1064 | echo_char_raw('\b', ldata); |
1065 | echo_char_raw(' ', ldata); | |
1066 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1067 | } |
1068 | } | |
1069 | } | |
1070 | if (kill_type == ERASE) | |
1071 | break; | |
1072 | } | |
ba2e68ac | 1073 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1074 | finish_erasing(ldata); |
1da177e4 LT |
1075 | } |
1076 | ||
1077 | /** | |
1078 | * isig - handle the ISIG optio | |
1079 | * @sig: signal | |
1080 | * @tty: terminal | |
1da177e4 | 1081 | * |
8c985d18 PH |
1082 | * Called when a signal is being sent due to terminal input. |
1083 | * Called from the driver receive_buf path so serialized. | |
17b82060 | 1084 | * |
8c985d18 | 1085 | * Locking: ctrl_lock |
1da177e4 | 1086 | */ |
4edf1827 | 1087 | |
8c985d18 | 1088 | static inline void isig(int sig, struct tty_struct *tty) |
1da177e4 | 1089 | { |
8c985d18 PH |
1090 | struct pid *tty_pgrp = tty_get_pgrp(tty); |
1091 | if (tty_pgrp) { | |
1092 | kill_pgrp(tty_pgrp, sig, 1); | |
1093 | put_pid(tty_pgrp); | |
1da177e4 LT |
1094 | } |
1095 | } | |
1096 | ||
1097 | /** | |
1098 | * n_tty_receive_break - handle break | |
1099 | * @tty: terminal | |
1100 | * | |
1101 | * An RS232 break event has been hit in the incoming bitstream. This | |
1102 | * can cause a variety of events depending upon the termios settings. | |
1103 | * | |
6d76bd26 PH |
1104 | * n_tty_receive_buf()/producer path: |
1105 | * caller holds non-exclusive termios_rwsem | |
1106 | * publishes read_head via put_tty_queue() | |
1107 | * | |
1108 | * Note: may get exclusive termios_rwsem if flushing input buffer | |
1da177e4 | 1109 | */ |
4edf1827 | 1110 | |
1da177e4 LT |
1111 | static inline void n_tty_receive_break(struct tty_struct *tty) |
1112 | { | |
57c94121 JS |
1113 | struct n_tty_data *ldata = tty->disc_data; |
1114 | ||
1da177e4 LT |
1115 | if (I_IGNBRK(tty)) |
1116 | return; | |
1117 | if (I_BRKINT(tty)) { | |
8c985d18 PH |
1118 | isig(SIGINT, tty); |
1119 | if (!L_NOFLSH(tty)) { | |
6d76bd26 PH |
1120 | /* flushing needs exclusive termios_rwsem */ |
1121 | up_read(&tty->termios_rwsem); | |
8c985d18 PH |
1122 | n_tty_flush_buffer(tty); |
1123 | tty_driver_flush_buffer(tty); | |
6d76bd26 | 1124 | down_read(&tty->termios_rwsem); |
8c985d18 | 1125 | } |
1da177e4 LT |
1126 | return; |
1127 | } | |
1128 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1129 | put_tty_queue('\377', ldata); |
1130 | put_tty_queue('\0', ldata); | |
1da177e4 | 1131 | } |
57c94121 | 1132 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1133 | wake_up_interruptible(&tty->read_wait); |
1134 | } | |
1135 | ||
1136 | /** | |
1137 | * n_tty_receive_overrun - handle overrun reporting | |
1138 | * @tty: terminal | |
1139 | * | |
1140 | * Data arrived faster than we could process it. While the tty | |
1141 | * driver has flagged this the bits that were missed are gone | |
1142 | * forever. | |
1143 | * | |
1144 | * Called from the receive_buf path so single threaded. Does not | |
1145 | * need locking as num_overrun and overrun_time are function | |
1146 | * private. | |
1147 | */ | |
4edf1827 | 1148 | |
1da177e4 LT |
1149 | static inline void n_tty_receive_overrun(struct tty_struct *tty) |
1150 | { | |
53c5ee2c | 1151 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1152 | char buf[64]; |
1153 | ||
53c5ee2c JS |
1154 | ldata->num_overrun++; |
1155 | if (time_after(jiffies, ldata->overrun_time + HZ) || | |
1156 | time_after(ldata->overrun_time, jiffies)) { | |
1da177e4 LT |
1157 | printk(KERN_WARNING "%s: %d input overrun(s)\n", |
1158 | tty_name(tty, buf), | |
53c5ee2c JS |
1159 | ldata->num_overrun); |
1160 | ldata->overrun_time = jiffies; | |
1161 | ldata->num_overrun = 0; | |
1da177e4 LT |
1162 | } |
1163 | } | |
1164 | ||
1165 | /** | |
1166 | * n_tty_receive_parity_error - error notifier | |
1167 | * @tty: terminal device | |
1168 | * @c: character | |
1169 | * | |
1170 | * Process a parity error and queue the right data to indicate | |
6d76bd26 PH |
1171 | * the error case if necessary. |
1172 | * | |
1173 | * n_tty_receive_buf()/producer path: | |
1174 | * caller holds non-exclusive termios_rwsem | |
1175 | * publishes read_head via put_tty_queue() | |
1da177e4 LT |
1176 | */ |
1177 | static inline void n_tty_receive_parity_error(struct tty_struct *tty, | |
1178 | unsigned char c) | |
1179 | { | |
57c94121 JS |
1180 | struct n_tty_data *ldata = tty->disc_data; |
1181 | ||
4edf1827 | 1182 | if (I_IGNPAR(tty)) |
1da177e4 | 1183 | return; |
1da177e4 | 1184 | if (I_PARMRK(tty)) { |
57c94121 JS |
1185 | put_tty_queue('\377', ldata); |
1186 | put_tty_queue('\0', ldata); | |
1187 | put_tty_queue(c, ldata); | |
1da177e4 | 1188 | } else if (I_INPCK(tty)) |
57c94121 | 1189 | put_tty_queue('\0', ldata); |
1da177e4 | 1190 | else |
57c94121 | 1191 | put_tty_queue(c, ldata); |
1da177e4 LT |
1192 | wake_up_interruptible(&tty->read_wait); |
1193 | } | |
1194 | ||
1195 | /** | |
1196 | * n_tty_receive_char - perform processing | |
1197 | * @tty: terminal device | |
1198 | * @c: character | |
1199 | * | |
1200 | * Process an individual character of input received from the driver. | |
4edf1827 | 1201 | * This is serialized with respect to itself by the rules for the |
1da177e4 | 1202 | * driver above. |
6d76bd26 PH |
1203 | * |
1204 | * n_tty_receive_buf()/producer path: | |
1205 | * caller holds non-exclusive termios_rwsem | |
1206 | * publishes canon_head if canonical mode is active | |
1207 | * otherwise, publishes read_head via put_tty_queue() | |
1da177e4 LT |
1208 | */ |
1209 | ||
1210 | static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) | |
1211 | { | |
53c5ee2c | 1212 | struct n_tty_data *ldata = tty->disc_data; |
acc71bba | 1213 | int parmrk; |
1da177e4 | 1214 | |
53c5ee2c | 1215 | if (ldata->raw) { |
57c94121 | 1216 | put_tty_queue(c, ldata); |
1da177e4 LT |
1217 | return; |
1218 | } | |
4edf1827 | 1219 | |
1da177e4 LT |
1220 | if (I_ISTRIP(tty)) |
1221 | c &= 0x7f; | |
1222 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
300a6204 | 1223 | c = tolower(c); |
1da177e4 | 1224 | |
26df6d13 | 1225 | if (L_EXTPROC(tty)) { |
57c94121 | 1226 | put_tty_queue(c, ldata); |
26df6d13 | 1227 | return; |
1228 | } | |
1229 | ||
54d2a37e | 1230 | if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && |
a88a69c9 JP |
1231 | I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && |
1232 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { | |
54d2a37e | 1233 | start_tty(tty); |
a88a69c9 JP |
1234 | process_echoes(tty); |
1235 | } | |
54d2a37e | 1236 | |
1da177e4 LT |
1237 | if (tty->closing) { |
1238 | if (I_IXON(tty)) { | |
a88a69c9 | 1239 | if (c == START_CHAR(tty)) { |
1da177e4 | 1240 | start_tty(tty); |
a88a69c9 | 1241 | process_echoes(tty); |
300a6204 | 1242 | } else if (c == STOP_CHAR(tty)) |
1da177e4 LT |
1243 | stop_tty(tty); |
1244 | } | |
1245 | return; | |
1246 | } | |
1247 | ||
1248 | /* | |
1249 | * If the previous character was LNEXT, or we know that this | |
1250 | * character is not one of the characters that we'll have to | |
1251 | * handle specially, do shortcut processing to speed things | |
1252 | * up. | |
1253 | */ | |
3fe780b3 | 1254 | if (!test_bit(c, ldata->process_char_map) || ldata->lnext) { |
53c5ee2c | 1255 | ldata->lnext = 0; |
acc71bba | 1256 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ce74117a | 1257 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1258 | /* beep if no space */ |
7e94b1d9 JP |
1259 | if (L_ECHO(tty)) |
1260 | process_output('\a', tty); | |
acc71bba JP |
1261 | return; |
1262 | } | |
1263 | if (L_ECHO(tty)) { | |
57c94121 | 1264 | finish_erasing(ldata); |
1da177e4 | 1265 | /* Record the column of first canon char. */ |
ba2e68ac | 1266 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1267 | echo_set_canon_col(ldata); |
1da177e4 | 1268 | echo_char(c, tty); |
17bd7907 | 1269 | commit_echoes(tty); |
1da177e4 | 1270 | } |
acc71bba | 1271 | if (parmrk) |
57c94121 JS |
1272 | put_tty_queue(c, ldata); |
1273 | put_tty_queue(c, ldata); | |
1da177e4 LT |
1274 | return; |
1275 | } | |
4edf1827 | 1276 | |
1da177e4 LT |
1277 | if (I_IXON(tty)) { |
1278 | if (c == START_CHAR(tty)) { | |
1279 | start_tty(tty); | |
17bd7907 | 1280 | commit_echoes(tty); |
1da177e4 LT |
1281 | return; |
1282 | } | |
1283 | if (c == STOP_CHAR(tty)) { | |
1284 | stop_tty(tty); | |
1285 | return; | |
1286 | } | |
1287 | } | |
575537b3 | 1288 | |
1da177e4 LT |
1289 | if (L_ISIG(tty)) { |
1290 | int signal; | |
1291 | signal = SIGINT; | |
1292 | if (c == INTR_CHAR(tty)) | |
1293 | goto send_signal; | |
1294 | signal = SIGQUIT; | |
1295 | if (c == QUIT_CHAR(tty)) | |
1296 | goto send_signal; | |
1297 | signal = SIGTSTP; | |
1298 | if (c == SUSP_CHAR(tty)) { | |
1299 | send_signal: | |
ec5b1157 | 1300 | if (!L_NOFLSH(tty)) { |
6d76bd26 PH |
1301 | /* flushing needs exclusive termios_rwsem */ |
1302 | up_read(&tty->termios_rwsem); | |
ec5b1157 | 1303 | n_tty_flush_buffer(tty); |
f34d7a5b | 1304 | tty_driver_flush_buffer(tty); |
6d76bd26 | 1305 | down_read(&tty->termios_rwsem); |
ec5b1157 | 1306 | } |
a88a69c9 JP |
1307 | if (I_IXON(tty)) |
1308 | start_tty(tty); | |
1309 | if (L_ECHO(tty)) { | |
ec5b1157 | 1310 | echo_char(c, tty); |
17bd7907 | 1311 | commit_echoes(tty); |
a88a69c9 | 1312 | } |
8c985d18 | 1313 | isig(signal, tty); |
1da177e4 LT |
1314 | return; |
1315 | } | |
1316 | } | |
575537b3 JP |
1317 | |
1318 | if (c == '\r') { | |
1319 | if (I_IGNCR(tty)) | |
1320 | return; | |
1321 | if (I_ICRNL(tty)) | |
1322 | c = '\n'; | |
1323 | } else if (c == '\n' && I_INLCR(tty)) | |
1324 | c = '\r'; | |
1325 | ||
53c5ee2c | 1326 | if (ldata->icanon) { |
1da177e4 LT |
1327 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || |
1328 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1329 | eraser(c, tty); | |
17bd7907 | 1330 | commit_echoes(tty); |
1da177e4 LT |
1331 | return; |
1332 | } | |
1333 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
53c5ee2c | 1334 | ldata->lnext = 1; |
1da177e4 | 1335 | if (L_ECHO(tty)) { |
57c94121 | 1336 | finish_erasing(ldata); |
1da177e4 | 1337 | if (L_ECHOCTL(tty)) { |
57c94121 JS |
1338 | echo_char_raw('^', ldata); |
1339 | echo_char_raw('\b', ldata); | |
17bd7907 | 1340 | commit_echoes(tty); |
1da177e4 LT |
1341 | } |
1342 | } | |
1343 | return; | |
1344 | } | |
1345 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && | |
1346 | L_IEXTEN(tty)) { | |
bc5a5e3f | 1347 | size_t tail = ldata->canon_head; |
1da177e4 | 1348 | |
57c94121 | 1349 | finish_erasing(ldata); |
1da177e4 | 1350 | echo_char(c, tty); |
57c94121 | 1351 | echo_char_raw('\n', ldata); |
ba2e68ac | 1352 | while (tail != ldata->read_head) { |
bc5a5e3f PH |
1353 | echo_char(read_buf(ldata, tail), tty); |
1354 | tail++; | |
1da177e4 | 1355 | } |
17bd7907 | 1356 | commit_echoes(tty); |
1da177e4 LT |
1357 | return; |
1358 | } | |
1359 | if (c == '\n') { | |
ce74117a | 1360 | if (read_cnt(ldata) >= N_TTY_BUF_SIZE) { |
7e94b1d9 JP |
1361 | if (L_ECHO(tty)) |
1362 | process_output('\a', tty); | |
acc71bba JP |
1363 | return; |
1364 | } | |
1365 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
57c94121 | 1366 | echo_char_raw('\n', ldata); |
17bd7907 | 1367 | commit_echoes(tty); |
1da177e4 LT |
1368 | } |
1369 | goto handle_newline; | |
1370 | } | |
1371 | if (c == EOF_CHAR(tty)) { | |
ce74117a | 1372 | if (read_cnt(ldata) >= N_TTY_BUF_SIZE) |
acc71bba | 1373 | return; |
ba2e68ac | 1374 | if (ldata->canon_head != ldata->read_head) |
4edf1827 | 1375 | set_bit(TTY_PUSH, &tty->flags); |
1da177e4 LT |
1376 | c = __DISABLED_CHAR; |
1377 | goto handle_newline; | |
1378 | } | |
1379 | if ((c == EOL_CHAR(tty)) || | |
1380 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
acc71bba JP |
1381 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) |
1382 | ? 1 : 0; | |
ce74117a | 1383 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk)) { |
7e94b1d9 JP |
1384 | if (L_ECHO(tty)) |
1385 | process_output('\a', tty); | |
acc71bba JP |
1386 | return; |
1387 | } | |
1da177e4 LT |
1388 | /* |
1389 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1390 | */ | |
1391 | if (L_ECHO(tty)) { | |
1da177e4 | 1392 | /* Record the column of first canon char. */ |
ba2e68ac | 1393 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1394 | echo_set_canon_col(ldata); |
1da177e4 | 1395 | echo_char(c, tty); |
17bd7907 | 1396 | commit_echoes(tty); |
1da177e4 LT |
1397 | } |
1398 | /* | |
1399 | * XXX does PARMRK doubling happen for | |
1400 | * EOL_CHAR and EOL2_CHAR? | |
1401 | */ | |
acc71bba | 1402 | if (parmrk) |
57c94121 | 1403 | put_tty_queue(c, ldata); |
1da177e4 | 1404 | |
4edf1827 | 1405 | handle_newline: |
bc5a5e3f | 1406 | set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); |
6d76bd26 | 1407 | put_tty_queue(c, ldata); |
ba2e68ac | 1408 | ldata->canon_head = ldata->read_head; |
1da177e4 LT |
1409 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1410 | if (waitqueue_active(&tty->read_wait)) | |
1411 | wake_up_interruptible(&tty->read_wait); | |
1412 | return; | |
1413 | } | |
1414 | } | |
4edf1827 | 1415 | |
acc71bba | 1416 | parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; |
ce74117a | 1417 | if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) { |
acc71bba | 1418 | /* beep if no space */ |
7e94b1d9 JP |
1419 | if (L_ECHO(tty)) |
1420 | process_output('\a', tty); | |
acc71bba JP |
1421 | return; |
1422 | } | |
1423 | if (L_ECHO(tty)) { | |
57c94121 | 1424 | finish_erasing(ldata); |
1da177e4 | 1425 | if (c == '\n') |
57c94121 | 1426 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1427 | else { |
1428 | /* Record the column of first canon char. */ | |
ba2e68ac | 1429 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1430 | echo_set_canon_col(ldata); |
1da177e4 LT |
1431 | echo_char(c, tty); |
1432 | } | |
17bd7907 | 1433 | commit_echoes(tty); |
1da177e4 LT |
1434 | } |
1435 | ||
acc71bba | 1436 | if (parmrk) |
57c94121 | 1437 | put_tty_queue(c, ldata); |
1da177e4 | 1438 | |
57c94121 | 1439 | put_tty_queue(c, ldata); |
4edf1827 | 1440 | } |
1da177e4 | 1441 | |
1da177e4 LT |
1442 | /** |
1443 | * n_tty_receive_buf - data receive | |
1444 | * @tty: terminal device | |
1445 | * @cp: buffer | |
1446 | * @fp: flag buffer | |
1447 | * @count: characters | |
1448 | * | |
1449 | * Called by the terminal driver when a block of characters has | |
1450 | * been received. This function must be called from soft contexts | |
1451 | * not from interrupt context. The driver is responsible for making | |
1452 | * calls one at a time and in order (or using flush_to_ldisc) | |
6d76bd26 PH |
1453 | * |
1454 | * n_tty_receive_buf()/producer path: | |
1455 | * claims non-exclusive termios_rwsem | |
1456 | * publishes read_head and canon_head | |
1da177e4 | 1457 | */ |
4edf1827 | 1458 | |
24a89d1c PH |
1459 | static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1460 | char *fp, int count) | |
1da177e4 | 1461 | { |
53c5ee2c | 1462 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1463 | const unsigned char *p; |
1464 | char *f, flags = TTY_NORMAL; | |
1da177e4 | 1465 | char buf[64]; |
1da177e4 | 1466 | |
53c5ee2c | 1467 | if (ldata->real_raw) { |
d1913e39 PH |
1468 | size_t n, head; |
1469 | ||
1470 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1471 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1472 | n = min_t(size_t, count, n); | |
1473 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1474 | ldata->read_head += n; | |
1475 | cp += n; | |
1476 | count -= n; | |
1477 | ||
1478 | head = ldata->read_head & (N_TTY_BUF_SIZE - 1); | |
1479 | n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); | |
1480 | n = min_t(size_t, count, n); | |
1481 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1482 | ldata->read_head += n; | |
1da177e4 | 1483 | } else { |
d1913e39 PH |
1484 | int i; |
1485 | ||
4edf1827 | 1486 | for (i = count, p = cp, f = fp; i; i--, p++) { |
1da177e4 LT |
1487 | if (f) |
1488 | flags = *f++; | |
1489 | switch (flags) { | |
1490 | case TTY_NORMAL: | |
1491 | n_tty_receive_char(tty, *p); | |
1492 | break; | |
1493 | case TTY_BREAK: | |
1494 | n_tty_receive_break(tty); | |
1495 | break; | |
1496 | case TTY_PARITY: | |
1497 | case TTY_FRAME: | |
1498 | n_tty_receive_parity_error(tty, *p); | |
1499 | break; | |
1500 | case TTY_OVERRUN: | |
1501 | n_tty_receive_overrun(tty); | |
1502 | break; | |
1503 | default: | |
4edf1827 | 1504 | printk(KERN_ERR "%s: unknown flag %d\n", |
1da177e4 LT |
1505 | tty_name(tty, buf), flags); |
1506 | break; | |
1507 | } | |
1508 | } | |
f34d7a5b AC |
1509 | if (tty->ops->flush_chars) |
1510 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1511 | } |
1512 | ||
ce74117a | 1513 | if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) || |
26df6d13 | 1514 | L_EXTPROC(tty)) { |
1da177e4 LT |
1515 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
1516 | if (waitqueue_active(&tty->read_wait)) | |
1517 | wake_up_interruptible(&tty->read_wait); | |
1518 | } | |
1519 | ||
6367ca72 | 1520 | n_tty_check_throttle(tty); |
1da177e4 LT |
1521 | } |
1522 | ||
24a89d1c PH |
1523 | static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
1524 | char *fp, int count) | |
1525 | { | |
9356b535 | 1526 | down_read(&tty->termios_rwsem); |
24a89d1c | 1527 | __receive_buf(tty, cp, fp, count); |
9356b535 | 1528 | up_read(&tty->termios_rwsem); |
24a89d1c PH |
1529 | } |
1530 | ||
1531 | static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, | |
1532 | char *fp, int count) | |
1533 | { | |
1534 | struct n_tty_data *ldata = tty->disc_data; | |
1535 | int room; | |
1536 | ||
9356b535 PH |
1537 | down_read(&tty->termios_rwsem); |
1538 | ||
24a89d1c PH |
1539 | tty->receive_room = room = receive_room(tty); |
1540 | if (!room) | |
1541 | ldata->no_room = 1; | |
1542 | count = min(count, room); | |
1543 | if (count) | |
1544 | __receive_buf(tty, cp, fp, count); | |
1545 | ||
9356b535 PH |
1546 | up_read(&tty->termios_rwsem); |
1547 | ||
24a89d1c PH |
1548 | return count; |
1549 | } | |
1550 | ||
1da177e4 LT |
1551 | int is_ignored(int sig) |
1552 | { | |
1553 | return (sigismember(¤t->blocked, sig) || | |
4edf1827 | 1554 | current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
1da177e4 LT |
1555 | } |
1556 | ||
1557 | /** | |
1558 | * n_tty_set_termios - termios data changed | |
1559 | * @tty: terminal | |
1560 | * @old: previous data | |
1561 | * | |
1562 | * Called by the tty layer when the user changes termios flags so | |
1563 | * that the line discipline can plan ahead. This function cannot sleep | |
4edf1827 | 1564 | * and is protected from re-entry by the tty layer. The user is |
1da177e4 LT |
1565 | * guaranteed that this function will not be re-entered or in progress |
1566 | * when the ldisc is closed. | |
17b82060 | 1567 | * |
6a1c0680 | 1568 | * Locking: Caller holds tty->termios_rwsem |
1da177e4 | 1569 | */ |
4edf1827 AC |
1570 | |
1571 | static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
1da177e4 | 1572 | { |
53c5ee2c | 1573 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1574 | int canon_change = 1; |
47afa7a5 AC |
1575 | |
1576 | if (old) | |
adc8d746 | 1577 | canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON; |
47afa7a5 | 1578 | if (canon_change) { |
3fe780b3 | 1579 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
ba2e68ac | 1580 | ldata->canon_head = ldata->read_tail; |
53c5ee2c | 1581 | ldata->erasing = 0; |
6f9b028a | 1582 | ldata->lnext = 0; |
47afa7a5 AC |
1583 | } |
1584 | ||
ce74117a | 1585 | if (canon_change && !L_ICANON(tty) && read_cnt(ldata)) |
47afa7a5 | 1586 | wake_up_interruptible(&tty->read_wait); |
4edf1827 | 1587 | |
53c5ee2c | 1588 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1589 | |
1da177e4 LT |
1590 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1591 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1592 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1593 | I_PARMRK(tty)) { | |
3fe780b3 | 1594 | bitmap_zero(ldata->process_char_map, 256); |
1da177e4 LT |
1595 | |
1596 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
3fe780b3 | 1597 | set_bit('\r', ldata->process_char_map); |
1da177e4 | 1598 | if (I_INLCR(tty)) |
3fe780b3 | 1599 | set_bit('\n', ldata->process_char_map); |
1da177e4 LT |
1600 | |
1601 | if (L_ICANON(tty)) { | |
3fe780b3 JS |
1602 | set_bit(ERASE_CHAR(tty), ldata->process_char_map); |
1603 | set_bit(KILL_CHAR(tty), ldata->process_char_map); | |
1604 | set_bit(EOF_CHAR(tty), ldata->process_char_map); | |
1605 | set_bit('\n', ldata->process_char_map); | |
1606 | set_bit(EOL_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1607 | if (L_IEXTEN(tty)) { |
1608 | set_bit(WERASE_CHAR(tty), | |
3fe780b3 | 1609 | ldata->process_char_map); |
1da177e4 | 1610 | set_bit(LNEXT_CHAR(tty), |
3fe780b3 | 1611 | ldata->process_char_map); |
1da177e4 | 1612 | set_bit(EOL2_CHAR(tty), |
3fe780b3 | 1613 | ldata->process_char_map); |
1da177e4 LT |
1614 | if (L_ECHO(tty)) |
1615 | set_bit(REPRINT_CHAR(tty), | |
3fe780b3 | 1616 | ldata->process_char_map); |
1da177e4 LT |
1617 | } |
1618 | } | |
1619 | if (I_IXON(tty)) { | |
3fe780b3 JS |
1620 | set_bit(START_CHAR(tty), ldata->process_char_map); |
1621 | set_bit(STOP_CHAR(tty), ldata->process_char_map); | |
1da177e4 LT |
1622 | } |
1623 | if (L_ISIG(tty)) { | |
3fe780b3 JS |
1624 | set_bit(INTR_CHAR(tty), ldata->process_char_map); |
1625 | set_bit(QUIT_CHAR(tty), ldata->process_char_map); | |
1626 | set_bit(SUSP_CHAR(tty), ldata->process_char_map); | |
1da177e4 | 1627 | } |
3fe780b3 | 1628 | clear_bit(__DISABLED_CHAR, ldata->process_char_map); |
53c5ee2c JS |
1629 | ldata->raw = 0; |
1630 | ldata->real_raw = 0; | |
1da177e4 | 1631 | } else { |
53c5ee2c | 1632 | ldata->raw = 1; |
1da177e4 LT |
1633 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1634 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1635 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1636 | ldata->real_raw = 1; |
1da177e4 | 1637 | else |
53c5ee2c | 1638 | ldata->real_raw = 0; |
1da177e4 | 1639 | } |
55db4c64 | 1640 | n_tty_set_room(tty); |
dab73b4e WY |
1641 | /* |
1642 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1643 | * been stopped by STOP_CHAR(tty) before it. | |
1644 | */ | |
1645 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { | |
1646 | start_tty(tty); | |
1647 | } | |
1648 | ||
f34d7a5b AC |
1649 | /* The termios change make the tty ready for I/O */ |
1650 | wake_up_interruptible(&tty->write_wait); | |
1651 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1652 | } |
1653 | ||
1654 | /** | |
1655 | * n_tty_close - close the ldisc for this tty | |
1656 | * @tty: device | |
1657 | * | |
4edf1827 AC |
1658 | * Called from the terminal layer when this line discipline is |
1659 | * being shut down, either because of a close or becsuse of a | |
1da177e4 LT |
1660 | * discipline change. The function will not be called while other |
1661 | * ldisc methods are in progress. | |
1662 | */ | |
4edf1827 | 1663 | |
1da177e4 LT |
1664 | static void n_tty_close(struct tty_struct *tty) |
1665 | { | |
70ece7a7 JS |
1666 | struct n_tty_data *ldata = tty->disc_data; |
1667 | ||
79901317 PH |
1668 | if (tty->link) |
1669 | n_tty_packet_mode_flush(tty); | |
1670 | ||
ba2e68ac JS |
1671 | kfree(ldata->read_buf); |
1672 | kfree(ldata->echo_buf); | |
70ece7a7 | 1673 | kfree(ldata); |
70ece7a7 | 1674 | tty->disc_data = NULL; |
1da177e4 LT |
1675 | } |
1676 | ||
1677 | /** | |
1678 | * n_tty_open - open an ldisc | |
1679 | * @tty: terminal to open | |
1680 | * | |
4edf1827 | 1681 | * Called when this line discipline is being attached to the |
1da177e4 LT |
1682 | * terminal device. Can sleep. Called serialized so that no |
1683 | * other events will occur in parallel. No further open will occur | |
1684 | * until a close. | |
1685 | */ | |
1686 | ||
1687 | static int n_tty_open(struct tty_struct *tty) | |
1688 | { | |
70ece7a7 JS |
1689 | struct n_tty_data *ldata; |
1690 | ||
1691 | ldata = kzalloc(sizeof(*ldata), GFP_KERNEL); | |
1692 | if (!ldata) | |
1693 | goto err; | |
1694 | ||
53c5ee2c | 1695 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1696 | mutex_init(&ldata->atomic_read_lock); |
1697 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1698 | |
a88a69c9 | 1699 | /* These are ugly. Currently a malloc failure here can panic */ |
ba2e68ac JS |
1700 | ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); |
1701 | ldata->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); | |
1702 | if (!ldata->read_buf || !ldata->echo_buf) | |
b91939f5 | 1703 | goto err_free_bufs; |
0b4068a1 | 1704 | |
70ece7a7 | 1705 | tty->disc_data = ldata; |
b66f4fa5 | 1706 | reset_buffer_flags(tty->disc_data); |
53c5ee2c | 1707 | ldata->column = 0; |
f6c8dbe6 | 1708 | ldata->minimum_to_wake = 1; |
1da177e4 | 1709 | tty->closing = 0; |
b66f4fa5 PH |
1710 | /* indicate buffer work may resume */ |
1711 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1712 | n_tty_set_termios(tty, NULL); | |
1713 | tty_unthrottle(tty); | |
70ece7a7 | 1714 | |
1da177e4 | 1715 | return 0; |
b91939f5 | 1716 | err_free_bufs: |
ba2e68ac JS |
1717 | kfree(ldata->read_buf); |
1718 | kfree(ldata->echo_buf); | |
70ece7a7 JS |
1719 | kfree(ldata); |
1720 | err: | |
b91939f5 | 1721 | return -ENOMEM; |
1da177e4 LT |
1722 | } |
1723 | ||
1724 | static inline int input_available_p(struct tty_struct *tty, int amt) | |
1725 | { | |
53c5ee2c JS |
1726 | struct n_tty_data *ldata = tty->disc_data; |
1727 | ||
53c5ee2c | 1728 | if (ldata->icanon && !L_EXTPROC(tty)) { |
a73d3d69 | 1729 | if (ldata->canon_head != ldata->read_tail) |
1da177e4 | 1730 | return 1; |
ce74117a | 1731 | } else if (read_cnt(ldata) >= (amt ? amt : 1)) |
1da177e4 LT |
1732 | return 1; |
1733 | ||
1734 | return 0; | |
1735 | } | |
1736 | ||
1737 | /** | |
bbd20759 | 1738 | * copy_from_read_buf - copy read data directly |
1da177e4 LT |
1739 | * @tty: terminal device |
1740 | * @b: user data | |
1741 | * @nr: size of data | |
1742 | * | |
11a96d18 | 1743 | * Helper function to speed up n_tty_read. It is only called when |
1da177e4 LT |
1744 | * ICANON is off; it copies characters straight from the tty queue to |
1745 | * user space directly. It can be profitably called twice; once to | |
1746 | * drain the space from the tail pointer to the (physical) end of the | |
1747 | * buffer, and once to drain the space from the (physical) beginning of | |
1748 | * the buffer to head pointer. | |
1749 | * | |
bddc7152 | 1750 | * Called under the ldata->atomic_read_lock sem |
1da177e4 | 1751 | * |
6d76bd26 PH |
1752 | * n_tty_read()/consumer path: |
1753 | * caller holds non-exclusive termios_rwsem | |
1754 | * read_tail published | |
1da177e4 | 1755 | */ |
4edf1827 | 1756 | |
33f0f88f | 1757 | static int copy_from_read_buf(struct tty_struct *tty, |
1da177e4 LT |
1758 | unsigned char __user **b, |
1759 | size_t *nr) | |
1760 | ||
1761 | { | |
53c5ee2c | 1762 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1763 | int retval; |
1764 | size_t n; | |
3fa10cc8 | 1765 | bool is_eof; |
bc5a5e3f | 1766 | size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
1da177e4 LT |
1767 | |
1768 | retval = 0; | |
bc5a5e3f | 1769 | n = min(read_cnt(ldata), N_TTY_BUF_SIZE - tail); |
1da177e4 | 1770 | n = min(*nr, n); |
1da177e4 | 1771 | if (n) { |
bc5a5e3f | 1772 | retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
1da177e4 | 1773 | n -= retval; |
bc5a5e3f PH |
1774 | is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); |
1775 | tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, | |
53c5ee2c | 1776 | ldata->icanon); |
bc5a5e3f | 1777 | ldata->read_tail += n; |
26df6d13 | 1778 | /* Turn single EOF into zero-length read */ |
ce74117a | 1779 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && !read_cnt(ldata)) |
3fa10cc8 | 1780 | n = 0; |
1da177e4 LT |
1781 | *b += n; |
1782 | *nr -= n; | |
1783 | } | |
1784 | return retval; | |
1785 | } | |
1786 | ||
88bb0de3 | 1787 | /** |
32f13521 | 1788 | * canon_copy_from_read_buf - copy read data in canonical mode |
88bb0de3 PH |
1789 | * @tty: terminal device |
1790 | * @b: user data | |
1791 | * @nr: size of data | |
1792 | * | |
1793 | * Helper function for n_tty_read. It is only called when ICANON is on; | |
32f13521 PH |
1794 | * it copies one line of input up to and including the line-delimiting |
1795 | * character into the user-space buffer. | |
88bb0de3 PH |
1796 | * |
1797 | * Called under the atomic_read_lock mutex | |
6d76bd26 PH |
1798 | * |
1799 | * n_tty_read()/consumer path: | |
1800 | * caller holds non-exclusive termios_rwsem | |
1801 | * read_tail published | |
88bb0de3 PH |
1802 | */ |
1803 | ||
32f13521 PH |
1804 | static int canon_copy_from_read_buf(struct tty_struct *tty, |
1805 | unsigned char __user **b, | |
1806 | size_t *nr) | |
88bb0de3 PH |
1807 | { |
1808 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 1809 | size_t n, size, more, c; |
bc5a5e3f PH |
1810 | size_t eol; |
1811 | size_t tail; | |
1812 | int ret, found = 0; | |
88bb0de3 PH |
1813 | |
1814 | /* N.B. avoid overrun if nr == 0 */ | |
ce74117a | 1815 | n = min(*nr, read_cnt(ldata)); |
6d76bd26 | 1816 | if (!n) |
32f13521 | 1817 | return 0; |
88bb0de3 | 1818 | |
bc5a5e3f | 1819 | tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); |
32f13521 PH |
1820 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
1821 | ||
bc5a5e3f | 1822 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
1823 | __func__, *nr, tail, n, size); |
1824 | ||
1825 | eol = find_next_bit(ldata->read_flags, size, tail); | |
1826 | more = n - (size - tail); | |
1827 | if (eol == N_TTY_BUF_SIZE && more) { | |
1828 | /* scan wrapped without finding set bit */ | |
1829 | eol = find_next_bit(ldata->read_flags, more, 0); | |
1830 | if (eol != more) | |
1831 | found = 1; | |
1832 | } else if (eol != size) | |
1833 | found = 1; | |
1834 | ||
1835 | size = N_TTY_BUF_SIZE - tail; | |
1836 | n = (found + eol + size) & (N_TTY_BUF_SIZE - 1); | |
1837 | c = n; | |
1838 | ||
bc5a5e3f | 1839 | if (found && read_buf(ldata, eol) == __DISABLED_CHAR) |
32f13521 PH |
1840 | n--; |
1841 | ||
bc5a5e3f | 1842 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", |
32f13521 PH |
1843 | __func__, eol, found, n, c, size, more); |
1844 | ||
32f13521 | 1845 | if (n > size) { |
bc5a5e3f | 1846 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), size); |
32f13521 PH |
1847 | if (ret) |
1848 | return -EFAULT; | |
1849 | ret = copy_to_user(*b + size, ldata->read_buf, n - size); | |
1850 | } else | |
bc5a5e3f | 1851 | ret = copy_to_user(*b, read_buf_addr(ldata, tail), n); |
32f13521 PH |
1852 | |
1853 | if (ret) | |
1854 | return -EFAULT; | |
1855 | *b += n; | |
1856 | *nr -= n; | |
1857 | ||
a73d3d69 | 1858 | if (found) |
6d76bd26 PH |
1859 | clear_bit(eol, ldata->read_flags); |
1860 | smp_mb__after_clear_bit(); | |
1861 | ldata->read_tail += c; | |
88bb0de3 | 1862 | |
32f13521 PH |
1863 | if (found) |
1864 | tty_audit_push(tty); | |
88bb0de3 PH |
1865 | return 0; |
1866 | } | |
1867 | ||
cc4191dc | 1868 | extern ssize_t redirected_tty_write(struct file *, const char __user *, |
4edf1827 | 1869 | size_t, loff_t *); |
1da177e4 LT |
1870 | |
1871 | /** | |
1872 | * job_control - check job control | |
1873 | * @tty: tty | |
1874 | * @file: file handle | |
1875 | * | |
1876 | * Perform job control management checks on this file/tty descriptor | |
4edf1827 | 1877 | * and if appropriate send any needed signals and return a negative |
1da177e4 | 1878 | * error code if action should be taken. |
04f378b1 | 1879 | * |
01a5e440 PH |
1880 | * Locking: redirected write test is safe |
1881 | * current->signal->tty check is safe | |
1882 | * ctrl_lock to safely reference tty->pgrp | |
1da177e4 | 1883 | */ |
4edf1827 | 1884 | |
1da177e4 LT |
1885 | static int job_control(struct tty_struct *tty, struct file *file) |
1886 | { | |
1887 | /* Job control check -- must be done at start and after | |
1888 | every sleep (POSIX.1 7.1.1.4). */ | |
1889 | /* NOTE: not yet done after every sleep pending a thorough | |
1890 | check of the logic of this change. -- jlc */ | |
1891 | /* don't stop on /dev/console */ | |
01a5e440 PH |
1892 | if (file->f_op->write == redirected_tty_write || |
1893 | current->signal->tty != tty) | |
1894 | return 0; | |
1895 | ||
1896 | spin_lock_irq(&tty->ctrl_lock); | |
1897 | if (!tty->pgrp) | |
1898 | printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); | |
1899 | else if (task_pgrp(current) != tty->pgrp) { | |
1900 | spin_unlock_irq(&tty->ctrl_lock); | |
1901 | if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) | |
1902 | return -EIO; | |
1903 | kill_pgrp(task_pgrp(current), SIGTTIN, 1); | |
1904 | set_thread_flag(TIF_SIGPENDING); | |
1905 | return -ERESTARTSYS; | |
1da177e4 | 1906 | } |
01a5e440 | 1907 | spin_unlock_irq(&tty->ctrl_lock); |
1da177e4 LT |
1908 | return 0; |
1909 | } | |
4edf1827 | 1910 | |
1da177e4 LT |
1911 | |
1912 | /** | |
11a96d18 | 1913 | * n_tty_read - read function for tty |
1da177e4 LT |
1914 | * @tty: tty device |
1915 | * @file: file object | |
1916 | * @buf: userspace buffer pointer | |
1917 | * @nr: size of I/O | |
1918 | * | |
1919 | * Perform reads for the line discipline. We are guaranteed that the | |
1920 | * line discipline will not be closed under us but we may get multiple | |
1921 | * parallel readers and must handle this ourselves. We may also get | |
1922 | * a hangup. Always called in user context, may sleep. | |
1923 | * | |
1924 | * This code must be sure never to sleep through a hangup. | |
6d76bd26 PH |
1925 | * |
1926 | * n_tty_read()/consumer path: | |
1927 | * claims non-exclusive termios_rwsem | |
1928 | * publishes read_tail | |
1da177e4 | 1929 | */ |
4edf1827 | 1930 | |
11a96d18 | 1931 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, |
1da177e4 LT |
1932 | unsigned char __user *buf, size_t nr) |
1933 | { | |
53c5ee2c | 1934 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
1935 | unsigned char __user *b = buf; |
1936 | DECLARE_WAITQUEUE(wait, current); | |
1937 | int c; | |
1938 | int minimum, time; | |
1939 | ssize_t retval = 0; | |
1940 | ssize_t size; | |
1941 | long timeout; | |
1942 | unsigned long flags; | |
04f378b1 | 1943 | int packet; |
1da177e4 LT |
1944 | |
1945 | do_it_again: | |
1da177e4 | 1946 | c = job_control(tty, file); |
4edf1827 | 1947 | if (c < 0) |
1da177e4 | 1948 | return c; |
4edf1827 | 1949 | |
9356b535 PH |
1950 | down_read(&tty->termios_rwsem); |
1951 | ||
1da177e4 LT |
1952 | minimum = time = 0; |
1953 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 1954 | if (!ldata->icanon) { |
1da177e4 LT |
1955 | minimum = MIN_CHAR(tty); |
1956 | if (minimum) { | |
a6e54319 | 1957 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 1958 | if (time) |
f6c8dbe6 | 1959 | ldata->minimum_to_wake = 1; |
1da177e4 | 1960 | else if (!waitqueue_active(&tty->read_wait) || |
f6c8dbe6 PH |
1961 | (ldata->minimum_to_wake > minimum)) |
1962 | ldata->minimum_to_wake = minimum; | |
1da177e4 | 1963 | } else { |
a6e54319 | 1964 | timeout = (HZ / 10) * TIME_CHAR(tty); |
f6c8dbe6 | 1965 | ldata->minimum_to_wake = minimum = 1; |
1da177e4 LT |
1966 | } |
1967 | } | |
1968 | ||
1969 | /* | |
1970 | * Internal serialization of reads. | |
1971 | */ | |
1972 | if (file->f_flags & O_NONBLOCK) { | |
9356b535 PH |
1973 | if (!mutex_trylock(&ldata->atomic_read_lock)) { |
1974 | up_read(&tty->termios_rwsem); | |
1da177e4 | 1975 | return -EAGAIN; |
9356b535 | 1976 | } |
4edf1827 | 1977 | } else { |
9356b535 PH |
1978 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) { |
1979 | up_read(&tty->termios_rwsem); | |
1da177e4 | 1980 | return -ERESTARTSYS; |
9356b535 | 1981 | } |
1da177e4 | 1982 | } |
04f378b1 | 1983 | packet = tty->packet; |
1da177e4 LT |
1984 | |
1985 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
1986 | while (nr) { |
1987 | /* First test for status change. */ | |
04f378b1 | 1988 | if (packet && tty->link->ctrl_status) { |
1da177e4 LT |
1989 | unsigned char cs; |
1990 | if (b != buf) | |
1991 | break; | |
04f378b1 | 1992 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
1da177e4 LT |
1993 | cs = tty->link->ctrl_status; |
1994 | tty->link->ctrl_status = 0; | |
04f378b1 | 1995 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
522ed776 | 1996 | if (tty_put_user(tty, cs, b++)) { |
1da177e4 LT |
1997 | retval = -EFAULT; |
1998 | b--; | |
1999 | break; | |
2000 | } | |
2001 | nr--; | |
2002 | break; | |
2003 | } | |
2004 | /* This statement must be first before checking for input | |
2005 | so that any interrupt will set the state back to | |
2006 | TASK_RUNNING. */ | |
2007 | set_current_state(TASK_INTERRUPTIBLE); | |
4edf1827 | 2008 | |
f6c8dbe6 | 2009 | if (((minimum - (b - buf)) < ldata->minimum_to_wake) && |
1da177e4 | 2010 | ((minimum - (b - buf)) >= 1)) |
f6c8dbe6 | 2011 | ldata->minimum_to_wake = (minimum - (b - buf)); |
4edf1827 | 2012 | |
1da177e4 LT |
2013 | if (!input_available_p(tty, 0)) { |
2014 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
2015 | retval = -EIO; | |
2016 | break; | |
2017 | } | |
2018 | if (tty_hung_up_p(file)) | |
2019 | break; | |
2020 | if (!timeout) | |
2021 | break; | |
2022 | if (file->f_flags & O_NONBLOCK) { | |
2023 | retval = -EAGAIN; | |
2024 | break; | |
2025 | } | |
2026 | if (signal_pending(current)) { | |
2027 | retval = -ERESTARTSYS; | |
2028 | break; | |
2029 | } | |
55db4c64 | 2030 | n_tty_set_room(tty); |
9356b535 PH |
2031 | up_read(&tty->termios_rwsem); |
2032 | ||
1da177e4 | 2033 | timeout = schedule_timeout(timeout); |
9356b535 PH |
2034 | |
2035 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2036 | continue; |
2037 | } | |
2038 | __set_current_state(TASK_RUNNING); | |
2039 | ||
2040 | /* Deal with packet mode. */ | |
04f378b1 | 2041 | if (packet && b == buf) { |
522ed776 | 2042 | if (tty_put_user(tty, TIOCPKT_DATA, b++)) { |
1da177e4 LT |
2043 | retval = -EFAULT; |
2044 | b--; | |
2045 | break; | |
2046 | } | |
2047 | nr--; | |
2048 | } | |
2049 | ||
53c5ee2c | 2050 | if (ldata->icanon && !L_EXTPROC(tty)) { |
32f13521 | 2051 | retval = canon_copy_from_read_buf(tty, &b, &nr); |
1da177e4 LT |
2052 | if (retval) |
2053 | break; | |
2054 | } else { | |
2055 | int uncopied; | |
04f378b1 AC |
2056 | /* The copy function takes the read lock and handles |
2057 | locking internally for this case */ | |
1da177e4 LT |
2058 | uncopied = copy_from_read_buf(tty, &b, &nr); |
2059 | uncopied += copy_from_read_buf(tty, &b, &nr); | |
2060 | if (uncopied) { | |
2061 | retval = -EFAULT; | |
2062 | break; | |
2063 | } | |
2064 | } | |
2065 | ||
6367ca72 | 2066 | n_tty_check_unthrottle(tty); |
1da177e4 LT |
2067 | |
2068 | if (b - buf >= minimum) | |
2069 | break; | |
2070 | if (time) | |
2071 | timeout = time; | |
2072 | } | |
bddc7152 | 2073 | mutex_unlock(&ldata->atomic_read_lock); |
1da177e4 LT |
2074 | remove_wait_queue(&tty->read_wait, &wait); |
2075 | ||
2076 | if (!waitqueue_active(&tty->read_wait)) | |
f6c8dbe6 | 2077 | ldata->minimum_to_wake = minimum; |
1da177e4 LT |
2078 | |
2079 | __set_current_state(TASK_RUNNING); | |
2080 | size = b - buf; | |
2081 | if (size) { | |
2082 | retval = size; | |
2083 | if (nr) | |
4edf1827 | 2084 | clear_bit(TTY_PUSH, &tty->flags); |
9356b535 PH |
2085 | } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) { |
2086 | up_read(&tty->termios_rwsem); | |
bbd20759 | 2087 | goto do_it_again; |
9356b535 | 2088 | } |
1da177e4 | 2089 | |
55db4c64 | 2090 | n_tty_set_room(tty); |
9356b535 | 2091 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2092 | return retval; |
2093 | } | |
2094 | ||
2095 | /** | |
11a96d18 | 2096 | * n_tty_write - write function for tty |
1da177e4 LT |
2097 | * @tty: tty device |
2098 | * @file: file object | |
2099 | * @buf: userspace buffer pointer | |
2100 | * @nr: size of I/O | |
2101 | * | |
a88a69c9 | 2102 | * Write function of the terminal device. This is serialized with |
1da177e4 | 2103 | * respect to other write callers but not to termios changes, reads |
a88a69c9 JP |
2104 | * and other such events. Since the receive code will echo characters, |
2105 | * thus calling driver write methods, the output_lock is used in | |
2106 | * the output processing functions called here as well as in the | |
2107 | * echo processing function to protect the column state and space | |
2108 | * left in the buffer. | |
1da177e4 LT |
2109 | * |
2110 | * This code must be sure never to sleep through a hangup. | |
a88a69c9 JP |
2111 | * |
2112 | * Locking: output_lock to protect column state and space left | |
2113 | * (note that the process_output*() functions take this | |
2114 | * lock themselves) | |
1da177e4 | 2115 | */ |
4edf1827 | 2116 | |
11a96d18 | 2117 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
a88a69c9 | 2118 | const unsigned char *buf, size_t nr) |
1da177e4 LT |
2119 | { |
2120 | const unsigned char *b = buf; | |
2121 | DECLARE_WAITQUEUE(wait, current); | |
2122 | int c; | |
2123 | ssize_t retval = 0; | |
2124 | ||
2125 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
2126 | if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { | |
2127 | retval = tty_check_change(tty); | |
2128 | if (retval) | |
2129 | return retval; | |
2130 | } | |
2131 | ||
9356b535 PH |
2132 | down_read(&tty->termios_rwsem); |
2133 | ||
a88a69c9 JP |
2134 | /* Write out any echoed characters that are still pending */ |
2135 | process_echoes(tty); | |
300a6204 | 2136 | |
1da177e4 LT |
2137 | add_wait_queue(&tty->write_wait, &wait); |
2138 | while (1) { | |
2139 | set_current_state(TASK_INTERRUPTIBLE); | |
2140 | if (signal_pending(current)) { | |
2141 | retval = -ERESTARTSYS; | |
2142 | break; | |
2143 | } | |
2144 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2145 | retval = -EIO; | |
2146 | break; | |
2147 | } | |
582f5590 | 2148 | if (O_OPOST(tty)) { |
1da177e4 | 2149 | while (nr > 0) { |
a88a69c9 | 2150 | ssize_t num = process_output_block(tty, b, nr); |
1da177e4 LT |
2151 | if (num < 0) { |
2152 | if (num == -EAGAIN) | |
2153 | break; | |
2154 | retval = num; | |
2155 | goto break_out; | |
2156 | } | |
2157 | b += num; | |
2158 | nr -= num; | |
2159 | if (nr == 0) | |
2160 | break; | |
2161 | c = *b; | |
a88a69c9 | 2162 | if (process_output(c, tty) < 0) |
1da177e4 LT |
2163 | break; |
2164 | b++; nr--; | |
2165 | } | |
f34d7a5b AC |
2166 | if (tty->ops->flush_chars) |
2167 | tty->ops->flush_chars(tty); | |
1da177e4 | 2168 | } else { |
d6afe27b | 2169 | while (nr > 0) { |
f34d7a5b | 2170 | c = tty->ops->write(tty, b, nr); |
d6afe27b RZ |
2171 | if (c < 0) { |
2172 | retval = c; | |
2173 | goto break_out; | |
2174 | } | |
2175 | if (!c) | |
2176 | break; | |
2177 | b += c; | |
2178 | nr -= c; | |
1da177e4 | 2179 | } |
1da177e4 LT |
2180 | } |
2181 | if (!nr) | |
2182 | break; | |
2183 | if (file->f_flags & O_NONBLOCK) { | |
2184 | retval = -EAGAIN; | |
2185 | break; | |
2186 | } | |
9356b535 PH |
2187 | up_read(&tty->termios_rwsem); |
2188 | ||
1da177e4 | 2189 | schedule(); |
9356b535 PH |
2190 | |
2191 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2192 | } |
2193 | break_out: | |
2194 | __set_current_state(TASK_RUNNING); | |
2195 | remove_wait_queue(&tty->write_wait, &wait); | |
ff8cb0fd TP |
2196 | if (b - buf != nr && tty->fasync) |
2197 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
9356b535 | 2198 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2199 | return (b - buf) ? b - buf : retval; |
2200 | } | |
2201 | ||
2202 | /** | |
11a96d18 | 2203 | * n_tty_poll - poll method for N_TTY |
1da177e4 LT |
2204 | * @tty: terminal device |
2205 | * @file: file accessing it | |
2206 | * @wait: poll table | |
2207 | * | |
2208 | * Called when the line discipline is asked to poll() for data or | |
2209 | * for special events. This code is not serialized with respect to | |
2210 | * other events save open/close. | |
2211 | * | |
2212 | * This code must be sure never to sleep through a hangup. | |
2213 | * Called without the kernel lock held - fine | |
1da177e4 | 2214 | */ |
4edf1827 | 2215 | |
11a96d18 | 2216 | static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2217 | poll_table *wait) |
1da177e4 | 2218 | { |
f6c8dbe6 | 2219 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 LT |
2220 | unsigned int mask = 0; |
2221 | ||
2222 | poll_wait(file, &tty->read_wait, wait); | |
2223 | poll_wait(file, &tty->write_wait, wait); | |
2224 | if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) | |
2225 | mask |= POLLIN | POLLRDNORM; | |
2226 | if (tty->packet && tty->link->ctrl_status) | |
2227 | mask |= POLLPRI | POLLIN | POLLRDNORM; | |
2228 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
2229 | mask |= POLLHUP; | |
2230 | if (tty_hung_up_p(file)) | |
2231 | mask |= POLLHUP; | |
2232 | if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { | |
2233 | if (MIN_CHAR(tty) && !TIME_CHAR(tty)) | |
f6c8dbe6 | 2234 | ldata->minimum_to_wake = MIN_CHAR(tty); |
1da177e4 | 2235 | else |
f6c8dbe6 | 2236 | ldata->minimum_to_wake = 1; |
1da177e4 | 2237 | } |
f34d7a5b AC |
2238 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2239 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2240 | tty_write_room(tty) > 0) | |
1da177e4 LT |
2241 | mask |= POLLOUT | POLLWRNORM; |
2242 | return mask; | |
2243 | } | |
2244 | ||
57c94121 | 2245 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2246 | { |
bc5a5e3f | 2247 | size_t nr, head, tail; |
47afa7a5 | 2248 | |
a73d3d69 | 2249 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2250 | return 0; |
ba2e68ac JS |
2251 | head = ldata->canon_head; |
2252 | tail = ldata->read_tail; | |
bc5a5e3f | 2253 | nr = head - tail; |
47afa7a5 AC |
2254 | /* Skip EOF-chars.. */ |
2255 | while (head != tail) { | |
bc5a5e3f PH |
2256 | if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && |
2257 | read_buf(ldata, tail) == __DISABLED_CHAR) | |
47afa7a5 | 2258 | nr--; |
bc5a5e3f | 2259 | tail++; |
47afa7a5 AC |
2260 | } |
2261 | return nr; | |
2262 | } | |
2263 | ||
2264 | static int n_tty_ioctl(struct tty_struct *tty, struct file *file, | |
2265 | unsigned int cmd, unsigned long arg) | |
2266 | { | |
ba2e68ac | 2267 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 AC |
2268 | int retval; |
2269 | ||
2270 | switch (cmd) { | |
2271 | case TIOCOUTQ: | |
2272 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2273 | case TIOCINQ: | |
6d76bd26 | 2274 | down_write(&tty->termios_rwsem); |
47afa7a5 | 2275 | if (L_ICANON(tty)) |
57c94121 | 2276 | retval = inq_canon(ldata); |
6d76bd26 PH |
2277 | else |
2278 | retval = read_cnt(ldata); | |
2279 | up_write(&tty->termios_rwsem); | |
47afa7a5 AC |
2280 | return put_user(retval, (unsigned int __user *) arg); |
2281 | default: | |
2282 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2283 | } | |
2284 | } | |
2285 | ||
f6c8dbe6 PH |
2286 | static void n_tty_fasync(struct tty_struct *tty, int on) |
2287 | { | |
2288 | struct n_tty_data *ldata = tty->disc_data; | |
2289 | ||
2290 | if (!waitqueue_active(&tty->read_wait)) { | |
2291 | if (on) | |
2292 | ldata->minimum_to_wake = 1; | |
2293 | else if (!tty->fasync) | |
2294 | ldata->minimum_to_wake = N_TTY_BUF_SIZE; | |
2295 | } | |
2296 | } | |
2297 | ||
a352def2 | 2298 | struct tty_ldisc_ops tty_ldisc_N_TTY = { |
e10cc1df PF |
2299 | .magic = TTY_LDISC_MAGIC, |
2300 | .name = "n_tty", | |
2301 | .open = n_tty_open, | |
2302 | .close = n_tty_close, | |
2303 | .flush_buffer = n_tty_flush_buffer, | |
2304 | .chars_in_buffer = n_tty_chars_in_buffer, | |
11a96d18 AC |
2305 | .read = n_tty_read, |
2306 | .write = n_tty_write, | |
e10cc1df PF |
2307 | .ioctl = n_tty_ioctl, |
2308 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2309 | .poll = n_tty_poll, |
e10cc1df | 2310 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 PH |
2311 | .write_wakeup = n_tty_write_wakeup, |
2312 | .fasync = n_tty_fasync, | |
24a89d1c | 2313 | .receive_buf2 = n_tty_receive_buf2, |
1da177e4 | 2314 | }; |
572b9adb RG |
2315 | |
2316 | /** | |
2317 | * n_tty_inherit_ops - inherit N_TTY methods | |
2318 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2319 | * | |
593fb1ae | 2320 | * Enables a 'subclass' line discipline to 'inherit' N_TTY |
572b9adb RG |
2321 | * methods. |
2322 | */ | |
2323 | ||
2324 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2325 | { | |
2326 | *ops = tty_ldisc_N_TTY; | |
2327 | ops->owner = NULL; | |
2328 | ops->refcount = ops->flags = 0; | |
2329 | } | |
2330 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); |