Commit | Line | Data |
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e3b3d0f5 | 1 | // SPDX-License-Identifier: GPL-1.0+ |
1da177e4 LT |
2 | /* |
3 | * n_tty.c --- implements the N_TTY line discipline. | |
4edf1827 | 4 | * |
1da177e4 LT |
5 | * This code used to be in tty_io.c, but things are getting hairy |
6 | * enough that it made sense to split things off. (The N_TTY | |
7 | * processing has changed so much that it's hardly recognizable, | |
8 | * anyway...) | |
9 | * | |
10 | * Note that the open routine for N_TTY is guaranteed never to return | |
11 | * an error. This is because Linux will fall back to setting a line | |
4edf1827 | 12 | * to N_TTY if it can not switch to any other line discipline. |
1da177e4 LT |
13 | * |
14 | * Written by Theodore Ts'o, Copyright 1994. | |
4edf1827 | 15 | * |
1da177e4 LT |
16 | * This file also contains code originally written by Linus Torvalds, |
17 | * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. | |
4edf1827 | 18 | * |
1da177e4 LT |
19 | * Reduced memory usage for older ARM systems - Russell King. |
20 | * | |
4edf1827 | 21 | * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of |
1da177e4 LT |
22 | * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> |
23 | * who actually finally proved there really was a race. | |
24 | * | |
25 | * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to | |
26 | * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. | |
11a96d18 | 27 | * Also fixed a bug in BLOCKING mode where n_tty_write returns |
1da177e4 LT |
28 | * EAGAIN |
29 | */ | |
30 | ||
8ed012d1 | 31 | #include <linux/bitmap.h> |
9db1be84 IJ |
32 | #include <linux/bitops.h> |
33 | #include <linux/ctype.h> | |
1da177e4 | 34 | #include <linux/errno.h> |
8ed012d1 | 35 | #include <linux/export.h> |
1da177e4 | 36 | #include <linux/fcntl.h> |
9db1be84 | 37 | #include <linux/file.h> |
8ed012d1 | 38 | #include <linux/jiffies.h> |
7e26c84d | 39 | #include <linux/math.h> |
9db1be84 | 40 | #include <linux/poll.h> |
593fb1ae | 41 | #include <linux/ratelimit.h> |
9db1be84 IJ |
42 | #include <linux/sched.h> |
43 | #include <linux/signal.h> | |
44 | #include <linux/slab.h> | |
45 | #include <linux/string.h> | |
9db1be84 IJ |
46 | #include <linux/tty.h> |
47 | #include <linux/types.h> | |
48 | #include <linux/uaccess.h> | |
86e35aea | 49 | #include <linux/vmalloc.h> |
9db1be84 | 50 | |
98602c01 | 51 | #include "tty.h" |
1da177e4 | 52 | |
a5db4826 VV |
53 | /* |
54 | * Until this number of characters is queued in the xmit buffer, select will | |
55 | * return "we have room for writes". | |
56 | */ | |
1da177e4 LT |
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 | |
a287885f | 87 | # define n_tty_trace(f, args...) no_printk(f, ##args) |
32f13521 PH |
88 | #endif |
89 | ||
70ece7a7 | 90 | struct n_tty_data { |
fb7aa03d PH |
91 | /* producer-published */ |
92 | size_t read_head; | |
70aca71f | 93 | size_t commit_head; |
fb7aa03d | 94 | size_t canon_head; |
9dfd16dd PH |
95 | size_t echo_head; |
96 | size_t echo_commit; | |
1075a6e2 | 97 | size_t echo_mark; |
1bb9d562 | 98 | DECLARE_BITMAP(char_map, 256); |
fb7aa03d PH |
99 | |
100 | /* private to n_tty_receive_overrun (single-threaded) */ | |
53c5ee2c | 101 | unsigned long overrun_time; |
c3b2b26f | 102 | unsigned int num_overrun; |
53c5ee2c | 103 | |
24a89d1c PH |
104 | /* non-atomic */ |
105 | bool no_room; | |
106 | ||
fb7aa03d | 107 | /* must hold exclusive termios_rwsem to reset these */ |
53c5ee2c | 108 | unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; |
4d0ed182 | 109 | unsigned char push:1; |
3fe780b3 | 110 | |
fb7aa03d | 111 | /* shared by producer and consumer */ |
b9b96b20 | 112 | u8 read_buf[N_TTY_BUF_SIZE]; |
3fe780b3 | 113 | DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); |
b9b96b20 | 114 | u8 echo_buf[N_TTY_BUF_SIZE]; |
ba2e68ac | 115 | |
fb7aa03d PH |
116 | /* consumer-published */ |
117 | size_t read_tail; | |
40d5e090 | 118 | size_t line_start; |
fb7aa03d | 119 | |
6bb6fa69 IJ |
120 | /* # of chars looked ahead (to find software flow control chars) */ |
121 | size_t lookahead_count; | |
122 | ||
fb7aa03d PH |
123 | /* protected by output lock */ |
124 | unsigned int column; | |
ba2e68ac | 125 | unsigned int canon_column; |
9dfd16dd | 126 | size_t echo_tail; |
bddc7152 JS |
127 | |
128 | struct mutex atomic_read_lock; | |
129 | struct mutex output_lock; | |
70ece7a7 JS |
130 | }; |
131 | ||
3d63b7e4 TH |
132 | #define MASK(x) ((x) & (N_TTY_BUF_SIZE - 1)) |
133 | ||
ce74117a PH |
134 | static inline size_t read_cnt(struct n_tty_data *ldata) |
135 | { | |
a2f73be8 | 136 | return ldata->read_head - ldata->read_tail; |
ce74117a PH |
137 | } |
138 | ||
b9b96b20 | 139 | static inline u8 read_buf(struct n_tty_data *ldata, size_t i) |
bc5a5e3f | 140 | { |
819287f0 | 141 | return ldata->read_buf[MASK(i)]; |
bc5a5e3f PH |
142 | } |
143 | ||
b9b96b20 | 144 | static inline u8 *read_buf_addr(struct n_tty_data *ldata, size_t i) |
bc5a5e3f | 145 | { |
819287f0 | 146 | return &ldata->read_buf[MASK(i)]; |
bc5a5e3f PH |
147 | } |
148 | ||
b9b96b20 | 149 | static inline u8 echo_buf(struct n_tty_data *ldata, size_t i) |
addaebcc | 150 | { |
ebec3f8f | 151 | smp_rmb(); /* Matches smp_wmb() in add_echo_byte(). */ |
819287f0 | 152 | return ldata->echo_buf[MASK(i)]; |
addaebcc PH |
153 | } |
154 | ||
b9b96b20 | 155 | static inline u8 *echo_buf_addr(struct n_tty_data *ldata, size_t i) |
addaebcc | 156 | { |
819287f0 | 157 | return &ldata->echo_buf[MASK(i)]; |
addaebcc PH |
158 | } |
159 | ||
b97b3d9f | 160 | /* If we are not echoing the data, perhaps this is a secret so erase it */ |
f6f847ff | 161 | static void zero_buffer(const struct tty_struct *tty, u8 *buffer, size_t size) |
b97b3d9f | 162 | { |
f6f847ff JS |
163 | if (L_ICANON(tty) && !L_ECHO(tty)) |
164 | memset(buffer, 0, size); | |
b97b3d9f GK |
165 | } |
166 | ||
5bedcf70 JS |
167 | static void tty_copy(const struct tty_struct *tty, void *to, size_t tail, |
168 | size_t n) | |
72586c60 LA |
169 | { |
170 | struct n_tty_data *ldata = tty->disc_data; | |
679e7c29 | 171 | size_t size = N_TTY_BUF_SIZE - tail; |
b97b3d9f | 172 | void *from = read_buf_addr(ldata, tail); |
679e7c29 PH |
173 | |
174 | if (n > size) { | |
309426ae | 175 | tty_audit_add_data(tty, from, size); |
3b830a9c LT |
176 | memcpy(to, from, size); |
177 | zero_buffer(tty, from, size); | |
679e7c29 PH |
178 | to += size; |
179 | n -= size; | |
180 | from = ldata->read_buf; | |
181 | } | |
72586c60 | 182 | |
309426ae | 183 | tty_audit_add_data(tty, from, n); |
3b830a9c LT |
184 | memcpy(to, from, n); |
185 | zero_buffer(tty, from, n); | |
72586c60 LA |
186 | } |
187 | ||
24a89d1c | 188 | /** |
98629663 JS |
189 | * n_tty_kick_worker - start input worker (if required) |
190 | * @tty: terminal | |
24a89d1c | 191 | * |
98629663 | 192 | * Re-schedules the flip buffer work if it may have stopped. |
24a89d1c | 193 | * |
98629663 JS |
194 | * Locking: |
195 | * * Caller holds exclusive %termios_rwsem, or | |
196 | * * n_tty_read()/consumer path: | |
197 | * holds non-exclusive %termios_rwsem | |
24a89d1c | 198 | */ |
5bedcf70 | 199 | static void n_tty_kick_worker(const struct tty_struct *tty) |
7879a9f9 | 200 | { |
24a89d1c PH |
201 | struct n_tty_data *ldata = tty->disc_data; |
202 | ||
2c5dc464 | 203 | /* Did the input worker stop? Restart it */ |
4903fde8 HL |
204 | if (unlikely(READ_ONCE(ldata->no_room))) { |
205 | WRITE_ONCE(ldata->no_room, 0); | |
24a89d1c | 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"); | |
e176058f | 215 | tty_buffer_restart_work(tty->port); |
ecbbfd44 | 216 | } |
55db4c64 LT |
217 | } |
218 | ||
5bedcf70 | 219 | static ssize_t chars_in_buffer(const struct tty_struct *tty) |
9a4aec2d | 220 | { |
5bedcf70 | 221 | const struct n_tty_data *ldata = tty->disc_data; |
d88c3c26 | 222 | size_t head = ldata->icanon ? ldata->canon_head : ldata->commit_head; |
9a4aec2d | 223 | |
d88c3c26 | 224 | return head - ldata->read_tail; |
9a4aec2d PH |
225 | } |
226 | ||
ee0bab83 | 227 | /** |
98629663 JS |
228 | * n_tty_write_wakeup - asynchronous I/O notifier |
229 | * @tty: tty device | |
ee0bab83 | 230 | * |
98629663 JS |
231 | * Required for the ptys, serial driver etc. since processes that attach |
232 | * themselves to the master and rely on ASYNC IO must be woken up. | |
ee0bab83 | 233 | */ |
ee0bab83 PH |
234 | static void n_tty_write_wakeup(struct tty_struct *tty) |
235 | { | |
7bccc365 PH |
236 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
237 | kill_fasync(&tty->fasync, SIGIO, POLL_OUT); | |
ee0bab83 PH |
238 | } |
239 | ||
4a23a4df | 240 | static void n_tty_check_throttle(struct tty_struct *tty) |
6367ca72 | 241 | { |
a342846f PH |
242 | struct n_tty_data *ldata = tty->disc_data; |
243 | ||
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 | */ | |
a342846f PH |
249 | if (ldata->icanon && ldata->canon_head == ldata->read_tail) |
250 | return; | |
251 | ||
043c8a7c | 252 | do { |
6367ca72 | 253 | tty_set_flow_change(tty, TTY_THROTTLE_SAFE); |
5e28cca1 | 254 | if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE) |
6367ca72 | 255 | break; |
5b4f9cf3 | 256 | } while (!tty_throttle_safe(tty)); |
043c8a7c | 257 | |
6367ca72 PH |
258 | __tty_set_flow_change(tty, 0); |
259 | } | |
260 | ||
4b293492 | 261 | static void n_tty_check_unthrottle(struct tty_struct *tty) |
6367ca72 | 262 | { |
6d27a63c | 263 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { |
3afb1b39 PH |
264 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) |
265 | return; | |
2c5dc464 | 266 | n_tty_kick_worker(tty); |
6d27a63c | 267 | tty_wakeup(tty->link); |
3afb1b39 PH |
268 | return; |
269 | } | |
270 | ||
6367ca72 PH |
271 | /* If there is enough space in the read buffer now, let the |
272 | * low-level driver know. We use chars_in_buffer() to | |
273 | * check the buffer, as it now knows about canonical mode. | |
274 | * Otherwise, if the driver is throttled and the line is | |
275 | * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, | |
276 | * we won't get any more characters. | |
277 | */ | |
278 | ||
043c8a7c | 279 | do { |
6367ca72 PH |
280 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); |
281 | if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) | |
282 | break; | |
043c8a7c | 283 | |
2c5dc464 | 284 | n_tty_kick_worker(tty); |
5b4f9cf3 | 285 | } while (!tty_unthrottle_safe(tty)); |
043c8a7c | 286 | |
6367ca72 PH |
287 | __tty_set_flow_change(tty, 0); |
288 | } | |
289 | ||
17b82060 | 290 | /** |
98629663 JS |
291 | * put_tty_queue - add character to tty |
292 | * @c: character | |
293 | * @ldata: n_tty data | |
17b82060 | 294 | * |
98629663 | 295 | * Add a character to the tty read_buf queue. |
6d76bd26 | 296 | * |
98629663 JS |
297 | * Locking: |
298 | * * n_tty_receive_buf()/producer path: | |
299 | * caller holds non-exclusive %termios_rwsem | |
17b82060 | 300 | */ |
b9b96b20 | 301 | static inline void put_tty_queue(u8 c, struct n_tty_data *ldata) |
1da177e4 | 302 | { |
8bfbe2de CR |
303 | *read_buf_addr(ldata, ldata->read_head) = c; |
304 | ldata->read_head++; | |
1da177e4 LT |
305 | } |
306 | ||
1da177e4 | 307 | /** |
98629663 JS |
308 | * reset_buffer_flags - reset buffer state |
309 | * @ldata: line disc data to reset | |
1da177e4 | 310 | * |
98629663 JS |
311 | * Reset the read buffer counters and clear the flags. Called from |
312 | * n_tty_open() and n_tty_flush_buffer(). | |
17b82060 | 313 | * |
98629663 JS |
314 | * Locking: |
315 | * * caller holds exclusive %termios_rwsem, or | |
316 | * * (locking is not required) | |
1da177e4 | 317 | */ |
b66f4fa5 | 318 | static void reset_buffer_flags(struct n_tty_data *ldata) |
1da177e4 | 319 | { |
a73d3d69 | 320 | ldata->read_head = ldata->canon_head = ldata->read_tail = 0; |
70aca71f | 321 | ldata->commit_head = 0; |
40d5e090 | 322 | ldata->line_start = 0; |
a88a69c9 | 323 | |
a73d3d69 | 324 | ldata->erasing = 0; |
3fe780b3 | 325 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 | 326 | ldata->push = 0; |
6bb6fa69 IJ |
327 | |
328 | ldata->lookahead_count = 0; | |
1da177e4 LT |
329 | } |
330 | ||
a30737ab PH |
331 | static void n_tty_packet_mode_flush(struct tty_struct *tty) |
332 | { | |
333 | unsigned long flags; | |
334 | ||
64d608db JS |
335 | if (tty->link->ctrl.packet) { |
336 | spin_lock_irqsave(&tty->ctrl.lock, flags); | |
337 | tty->ctrl.pktstatus |= TIOCPKT_FLUSHREAD; | |
338 | spin_unlock_irqrestore(&tty->ctrl.lock, flags); | |
e81107d4 | 339 | wake_up_interruptible(&tty->link->read_wait); |
a30737ab | 340 | } |
a30737ab PH |
341 | } |
342 | ||
1da177e4 | 343 | /** |
98629663 JS |
344 | * n_tty_flush_buffer - clean input queue |
345 | * @tty: terminal device | |
1da177e4 | 346 | * |
98629663 JS |
347 | * Flush the input buffer. Called when the tty layer wants the buffer flushed |
348 | * (eg at hangup) or when the %N_TTY line discipline internally has to clean | |
349 | * the pending queue (for example some signals). | |
1da177e4 | 350 | * |
98629663 JS |
351 | * Holds %termios_rwsem to exclude producer/consumer while buffer indices are |
352 | * reset. | |
6d76bd26 | 353 | * |
98629663 | 354 | * Locking: %ctrl.lock, exclusive %termios_rwsem |
1da177e4 | 355 | */ |
4edf1827 | 356 | static void n_tty_flush_buffer(struct tty_struct *tty) |
1da177e4 | 357 | { |
6d76bd26 | 358 | down_write(&tty->termios_rwsem); |
b66f4fa5 | 359 | reset_buffer_flags(tty->disc_data); |
2c5dc464 | 360 | n_tty_kick_worker(tty); |
4edf1827 | 361 | |
a30737ab PH |
362 | if (tty->link) |
363 | n_tty_packet_mode_flush(tty); | |
6d76bd26 | 364 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
365 | } |
366 | ||
1da177e4 | 367 | /** |
98629663 JS |
368 | * is_utf8_continuation - utf8 multibyte check |
369 | * @c: byte to check | |
1da177e4 | 370 | * |
98629663 JS |
371 | * Returns: true if the utf8 character @c is a multibyte continuation |
372 | * character. We use this to correctly compute the on-screen size of the | |
373 | * character when printing. | |
1da177e4 | 374 | */ |
b9b96b20 | 375 | static inline int is_utf8_continuation(u8 c) |
1da177e4 LT |
376 | { |
377 | return (c & 0xc0) == 0x80; | |
378 | } | |
379 | ||
380 | /** | |
98629663 JS |
381 | * is_continuation - multibyte check |
382 | * @c: byte to check | |
383 | * @tty: terminal device | |
1da177e4 | 384 | * |
98629663 JS |
385 | * Returns: true if the utf8 character @c is a multibyte continuation character |
386 | * and the terminal is in unicode mode. | |
1da177e4 | 387 | */ |
b9b96b20 | 388 | static inline int is_continuation(u8 c, const struct tty_struct *tty) |
1da177e4 LT |
389 | { |
390 | return I_IUTF8(tty) && is_utf8_continuation(c); | |
391 | } | |
392 | ||
393 | /** | |
98629663 JS |
394 | * do_output_char - output one character |
395 | * @c: character (or partial unicode symbol) | |
396 | * @tty: terminal device | |
397 | * @space: space available in tty driver write buffer | |
1da177e4 | 398 | * |
98629663 JS |
399 | * This is a helper function that handles one output character (including |
400 | * special characters like TAB, CR, LF, etc.), doing OPOST processing and | |
401 | * putting the results in the tty driver's write buffer. | |
a88a69c9 | 402 | * |
98629663 JS |
403 | * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY and NLDLY. |
404 | * They simply aren't relevant in the world today. If you ever need them, add | |
405 | * them here. | |
1da177e4 | 406 | * |
98629663 | 407 | * Returns: the number of bytes of buffer space used or -1 if no space left. |
a88a69c9 | 408 | * |
98629663 JS |
409 | * Locking: should be called under the %output_lock to protect the column state |
410 | * and space left in the buffer. | |
1da177e4 | 411 | */ |
b9b96b20 | 412 | static int do_output_char(u8 c, struct tty_struct *tty, int space) |
1da177e4 | 413 | { |
53c5ee2c | 414 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 | 415 | int spaces; |
1da177e4 | 416 | |
1da177e4 LT |
417 | if (!space) |
418 | return -1; | |
300a6204 | 419 | |
a88a69c9 JP |
420 | switch (c) { |
421 | case '\n': | |
422 | if (O_ONLRET(tty)) | |
53c5ee2c | 423 | ldata->column = 0; |
a88a69c9 JP |
424 | if (O_ONLCR(tty)) { |
425 | if (space < 2) | |
426 | return -1; | |
ba2e68ac | 427 | ldata->canon_column = ldata->column = 0; |
37f81fa1 | 428 | tty->ops->write(tty, "\r\n", 2); |
a88a69c9 JP |
429 | return 2; |
430 | } | |
ba2e68ac | 431 | ldata->canon_column = ldata->column; |
a88a69c9 JP |
432 | break; |
433 | case '\r': | |
53c5ee2c | 434 | if (O_ONOCR(tty) && ldata->column == 0) |
a88a69c9 JP |
435 | return 0; |
436 | if (O_OCRNL(tty)) { | |
437 | c = '\n'; | |
438 | if (O_ONLRET(tty)) | |
ba2e68ac | 439 | ldata->canon_column = ldata->column = 0; |
1da177e4 | 440 | break; |
a88a69c9 | 441 | } |
ba2e68ac | 442 | ldata->canon_column = ldata->column = 0; |
a88a69c9 JP |
443 | break; |
444 | case '\t': | |
53c5ee2c | 445 | spaces = 8 - (ldata->column & 7); |
a88a69c9 JP |
446 | if (O_TABDLY(tty) == XTABS) { |
447 | if (space < spaces) | |
448 | return -1; | |
53c5ee2c | 449 | ldata->column += spaces; |
a88a69c9 JP |
450 | tty->ops->write(tty, " ", spaces); |
451 | return spaces; | |
1da177e4 | 452 | } |
53c5ee2c | 453 | ldata->column += spaces; |
a88a69c9 JP |
454 | break; |
455 | case '\b': | |
53c5ee2c JS |
456 | if (ldata->column > 0) |
457 | ldata->column--; | |
a88a69c9 JP |
458 | break; |
459 | default: | |
a59c0d6f JP |
460 | if (!iscntrl(c)) { |
461 | if (O_OLCUC(tty)) | |
462 | c = toupper(c); | |
463 | if (!is_continuation(c, tty)) | |
53c5ee2c | 464 | ldata->column++; |
a59c0d6f | 465 | } |
a88a69c9 | 466 | break; |
1da177e4 | 467 | } |
a88a69c9 | 468 | |
f34d7a5b | 469 | tty_put_char(tty, c); |
a88a69c9 JP |
470 | return 1; |
471 | } | |
472 | ||
473 | /** | |
98629663 JS |
474 | * process_output - output post processor |
475 | * @c: character (or partial unicode symbol) | |
476 | * @tty: terminal device | |
477 | * | |
478 | * Output one character with OPOST processing. | |
a88a69c9 | 479 | * |
98629663 JS |
480 | * Returns: -1 when the output device is full and the character must be |
481 | * retried. | |
a88a69c9 | 482 | * |
98629663 JS |
483 | * Locking: %output_lock to protect column state and space left (also, this is |
484 | *called from n_tty_write() under the tty layer write lock). | |
a88a69c9 | 485 | */ |
b9b96b20 | 486 | static int process_output(u8 c, struct tty_struct *tty) |
a88a69c9 | 487 | { |
bddc7152 | 488 | struct n_tty_data *ldata = tty->disc_data; |
a88a69c9 JP |
489 | int space, retval; |
490 | ||
bddc7152 | 491 | mutex_lock(&ldata->output_lock); |
a88a69c9 JP |
492 | |
493 | space = tty_write_room(tty); | |
494 | retval = do_output_char(c, tty, space); | |
495 | ||
bddc7152 | 496 | mutex_unlock(&ldata->output_lock); |
a88a69c9 JP |
497 | if (retval < 0) |
498 | return -1; | |
499 | else | |
500 | return 0; | |
1da177e4 LT |
501 | } |
502 | ||
503 | /** | |
98629663 JS |
504 | * process_output_block - block post processor |
505 | * @tty: terminal device | |
506 | * @buf: character buffer | |
507 | * @nr: number of bytes to output | |
508 | * | |
509 | * Output a block of characters with OPOST processing. | |
510 | * | |
511 | * This path is used to speed up block console writes, among other things when | |
512 | * processing blocks of output data. It handles only the simple cases normally | |
513 | * found and helps to generate blocks of symbols for the console driver and | |
514 | * thus improve performance. | |
515 | * | |
516 | * Returns: the number of characters output. | |
517 | * | |
518 | * Locking: %output_lock to protect column state and space left (also, this is | |
519 | * called from n_tty_write() under the tty layer write lock). | |
1da177e4 | 520 | */ |
a88a69c9 | 521 | static ssize_t process_output_block(struct tty_struct *tty, |
b9b96b20 | 522 | const u8 *buf, unsigned int nr) |
1da177e4 | 523 | { |
53c5ee2c | 524 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 525 | int space; |
bbd20759 | 526 | int i; |
b9b96b20 | 527 | const u8 *cp; |
1da177e4 | 528 | |
bddc7152 | 529 | mutex_lock(&ldata->output_lock); |
a88a69c9 | 530 | |
f34d7a5b | 531 | space = tty_write_room(tty); |
9ef8927f | 532 | if (space <= 0) { |
bddc7152 | 533 | mutex_unlock(&ldata->output_lock); |
9ef8927f | 534 | return space; |
a88a69c9 | 535 | } |
1da177e4 LT |
536 | if (nr > space) |
537 | nr = space; | |
538 | ||
539 | for (i = 0, cp = buf; i < nr; i++, cp++) { | |
b9b96b20 | 540 | u8 c = *cp; |
a59c0d6f JP |
541 | |
542 | switch (c) { | |
1da177e4 LT |
543 | case '\n': |
544 | if (O_ONLRET(tty)) | |
53c5ee2c | 545 | ldata->column = 0; |
1da177e4 LT |
546 | if (O_ONLCR(tty)) |
547 | goto break_out; | |
ba2e68ac | 548 | ldata->canon_column = ldata->column; |
1da177e4 LT |
549 | break; |
550 | case '\r': | |
53c5ee2c | 551 | if (O_ONOCR(tty) && ldata->column == 0) |
1da177e4 LT |
552 | goto break_out; |
553 | if (O_OCRNL(tty)) | |
554 | goto break_out; | |
ba2e68ac | 555 | ldata->canon_column = ldata->column = 0; |
1da177e4 LT |
556 | break; |
557 | case '\t': | |
558 | goto break_out; | |
559 | case '\b': | |
53c5ee2c JS |
560 | if (ldata->column > 0) |
561 | ldata->column--; | |
1da177e4 LT |
562 | break; |
563 | default: | |
a59c0d6f JP |
564 | if (!iscntrl(c)) { |
565 | if (O_OLCUC(tty)) | |
566 | goto break_out; | |
567 | if (!is_continuation(c, tty)) | |
53c5ee2c | 568 | ldata->column++; |
a59c0d6f | 569 | } |
1da177e4 LT |
570 | break; |
571 | } | |
572 | } | |
573 | break_out: | |
f34d7a5b | 574 | i = tty->ops->write(tty, buf, i); |
a88a69c9 | 575 | |
bddc7152 | 576 | mutex_unlock(&ldata->output_lock); |
1da177e4 LT |
577 | return i; |
578 | } | |
579 | ||
2aa91851 JSS |
580 | static int n_tty_process_echo_ops(struct tty_struct *tty, size_t *tail, |
581 | int space) | |
582 | { | |
583 | struct n_tty_data *ldata = tty->disc_data; | |
584 | u8 op; | |
585 | ||
586 | /* | |
587 | * Since add_echo_byte() is called without holding output_lock, we | |
588 | * might see only portion of multi-byte operation. | |
589 | */ | |
590 | if (MASK(ldata->echo_commit) == MASK(*tail + 1)) | |
591 | return -ENODATA; | |
592 | ||
593 | /* | |
594 | * If the buffer byte is the start of a multi-byte operation, get the | |
595 | * next byte, which is either the op code or a control character value. | |
596 | */ | |
597 | op = echo_buf(ldata, *tail + 1); | |
598 | ||
599 | switch (op) { | |
600 | case ECHO_OP_ERASE_TAB: { | |
601 | unsigned int num_chars, num_bs; | |
602 | ||
603 | if (MASK(ldata->echo_commit) == MASK(*tail + 2)) | |
604 | return -ENODATA; | |
605 | ||
606 | num_chars = echo_buf(ldata, *tail + 2); | |
607 | ||
608 | /* | |
609 | * Determine how many columns to go back in order to erase the | |
610 | * tab. This depends on the number of columns used by other | |
611 | * characters within the tab area. If this (modulo 8) count is | |
612 | * from the start of input rather than from a previous tab, we | |
613 | * offset by canon column. Otherwise, tab spacing is normal. | |
614 | */ | |
615 | if (!(num_chars & 0x80)) | |
616 | num_chars += ldata->canon_column; | |
617 | num_bs = 8 - (num_chars & 7); | |
618 | ||
619 | if (num_bs > space) | |
620 | return -ENOSPC; | |
621 | ||
622 | space -= num_bs; | |
623 | while (num_bs--) { | |
624 | tty_put_char(tty, '\b'); | |
625 | if (ldata->column > 0) | |
626 | ldata->column--; | |
627 | } | |
628 | *tail += 3; | |
629 | break; | |
630 | } | |
631 | case ECHO_OP_SET_CANON_COL: | |
632 | ldata->canon_column = ldata->column; | |
633 | *tail += 2; | |
634 | break; | |
635 | ||
636 | case ECHO_OP_MOVE_BACK_COL: | |
637 | if (ldata->column > 0) | |
638 | ldata->column--; | |
639 | *tail += 2; | |
640 | break; | |
641 | ||
642 | case ECHO_OP_START: | |
643 | /* This is an escaped echo op start code */ | |
644 | if (!space) | |
645 | return -ENOSPC; | |
646 | ||
647 | tty_put_char(tty, ECHO_OP_START); | |
648 | ldata->column++; | |
649 | space--; | |
650 | *tail += 2; | |
651 | break; | |
652 | ||
653 | default: | |
654 | /* | |
655 | * If the op is not a special byte code, it is a ctrl char | |
656 | * tagged to be echoed as "^X" (where X is the letter | |
657 | * representing the control char). Note that we must ensure | |
658 | * there is enough space for the whole ctrl pair. | |
659 | */ | |
660 | if (space < 2) | |
661 | return -ENOSPC; | |
662 | ||
663 | tty_put_char(tty, '^'); | |
664 | tty_put_char(tty, op ^ 0100); | |
665 | ldata->column += 2; | |
666 | space -= 2; | |
667 | *tail += 2; | |
668 | break; | |
669 | } | |
670 | ||
671 | return space; | |
672 | } | |
673 | ||
a88a69c9 | 674 | /** |
98629663 JS |
675 | * __process_echoes - write pending echo characters |
676 | * @tty: terminal device | |
a88a69c9 | 677 | * |
98629663 JS |
678 | * Write previously buffered echo (and other ldisc-generated) characters to the |
679 | * tty. | |
a88a69c9 | 680 | * |
98629663 JS |
681 | * Characters generated by the ldisc (including echoes) need to be buffered |
682 | * because the driver's write buffer can fill during heavy program output. | |
683 | * Echoing straight to the driver will often fail under these conditions, | |
684 | * causing lost characters and resulting mismatches of ldisc state information. | |
a88a69c9 | 685 | * |
98629663 JS |
686 | * Since the ldisc state must represent the characters actually sent to the |
687 | * driver at the time of the write, operations like certain changes in column | |
688 | * state are also saved in the buffer and executed here. | |
a88a69c9 | 689 | * |
98629663 JS |
690 | * A circular fifo buffer is used so that the most recent characters are |
691 | * prioritized. Also, when control characters are echoed with a prefixed "^", | |
692 | * the pair is treated atomically and thus not separated. | |
a88a69c9 | 693 | * |
98629663 | 694 | * Locking: callers must hold %output_lock. |
a88a69c9 | 695 | */ |
bc5b1ec5 | 696 | static size_t __process_echoes(struct tty_struct *tty) |
a88a69c9 | 697 | { |
53c5ee2c | 698 | struct n_tty_data *ldata = tty->disc_data; |
bc5b1ec5 | 699 | int space, old_space; |
addaebcc | 700 | size_t tail; |
b9b96b20 | 701 | u8 c; |
a88a69c9 | 702 | |
bc5b1ec5 | 703 | old_space = space = tty_write_room(tty); |
a88a69c9 | 704 | |
addaebcc | 705 | tail = ldata->echo_tail; |
ebec3f8f | 706 | while (MASK(ldata->echo_commit) != MASK(tail)) { |
addaebcc | 707 | c = echo_buf(ldata, tail); |
a88a69c9 | 708 | if (c == ECHO_OP_START) { |
2aa91851 JSS |
709 | int ret = n_tty_process_echo_ops(tty, &tail, space); |
710 | if (ret == -ENODATA) | |
ebec3f8f | 711 | goto not_yet_stored; |
2aa91851 | 712 | if (ret < 0) |
a88a69c9 | 713 | break; |
2aa91851 | 714 | space = ret; |
a88a69c9 | 715 | } else { |
582f5590 | 716 | if (O_OPOST(tty)) { |
ee5aa7b8 JP |
717 | int retval = do_output_char(c, tty, space); |
718 | if (retval < 0) | |
719 | break; | |
720 | space -= retval; | |
721 | } else { | |
722 | if (!space) | |
723 | break; | |
724 | tty_put_char(tty, c); | |
725 | space -= 1; | |
726 | } | |
addaebcc | 727 | tail += 1; |
a88a69c9 | 728 | } |
a88a69c9 JP |
729 | } |
730 | ||
cbfd0340 PH |
731 | /* If the echo buffer is nearly full (so that the possibility exists |
732 | * of echo overrun before the next commit), then discard enough | |
733 | * data at the tail to prevent a subsequent overrun */ | |
ebec3f8f TH |
734 | while (ldata->echo_commit > tail && |
735 | ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { | |
c476f658 | 736 | if (echo_buf(ldata, tail) == ECHO_OP_START) { |
6f222536 | 737 | if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) |
cbfd0340 PH |
738 | tail += 3; |
739 | else | |
740 | tail += 2; | |
741 | } else | |
742 | tail++; | |
743 | } | |
744 | ||
ebec3f8f | 745 | not_yet_stored: |
addaebcc | 746 | ldata->echo_tail = tail; |
bc5b1ec5 | 747 | return old_space - space; |
019ebdf9 PH |
748 | } |
749 | ||
750 | static void commit_echoes(struct tty_struct *tty) | |
751 | { | |
752 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 753 | size_t nr, old, echoed; |
cbfd0340 PH |
754 | size_t head; |
755 | ||
ebec3f8f | 756 | mutex_lock(&ldata->output_lock); |
cbfd0340 | 757 | head = ldata->echo_head; |
1075a6e2 | 758 | ldata->echo_mark = head; |
cbfd0340 PH |
759 | old = ldata->echo_commit - ldata->echo_tail; |
760 | ||
761 | /* Process committed echoes if the accumulated # of bytes | |
762 | * is over the threshold (and try again each time another | |
763 | * block is accumulated) */ | |
764 | nr = head - ldata->echo_tail; | |
ebec3f8f TH |
765 | if (nr < ECHO_COMMIT_WATERMARK || |
766 | (nr % ECHO_BLOCK > old % ECHO_BLOCK)) { | |
767 | mutex_unlock(&ldata->output_lock); | |
cbfd0340 | 768 | return; |
ebec3f8f | 769 | } |
a88a69c9 | 770 | |
cbfd0340 | 771 | ldata->echo_commit = head; |
bc5b1ec5 | 772 | echoed = __process_echoes(tty); |
bddc7152 | 773 | mutex_unlock(&ldata->output_lock); |
a88a69c9 | 774 | |
bc5b1ec5 | 775 | if (echoed && tty->ops->flush_chars) |
a88a69c9 JP |
776 | tty->ops->flush_chars(tty); |
777 | } | |
778 | ||
019ebdf9 | 779 | static void process_echoes(struct tty_struct *tty) |
17bd7907 PH |
780 | { |
781 | struct n_tty_data *ldata = tty->disc_data; | |
bc5b1ec5 | 782 | size_t echoed; |
17bd7907 | 783 | |
e2613be5 | 784 | if (ldata->echo_mark == ldata->echo_tail) |
019ebdf9 PH |
785 | return; |
786 | ||
787 | mutex_lock(&ldata->output_lock); | |
1075a6e2 | 788 | ldata->echo_commit = ldata->echo_mark; |
bc5b1ec5 | 789 | echoed = __process_echoes(tty); |
019ebdf9 PH |
790 | mutex_unlock(&ldata->output_lock); |
791 | ||
bc5b1ec5 | 792 | if (echoed && tty->ops->flush_chars) |
019ebdf9 | 793 | tty->ops->flush_chars(tty); |
17bd7907 PH |
794 | } |
795 | ||
1075a6e2 | 796 | /* NB: echo_mark and echo_head should be equivalent here */ |
cbfd0340 PH |
797 | static void flush_echoes(struct tty_struct *tty) |
798 | { | |
799 | struct n_tty_data *ldata = tty->disc_data; | |
800 | ||
39434abd PH |
801 | if ((!L_ECHO(tty) && !L_ECHONL(tty)) || |
802 | ldata->echo_commit == ldata->echo_head) | |
cbfd0340 PH |
803 | return; |
804 | ||
805 | mutex_lock(&ldata->output_lock); | |
806 | ldata->echo_commit = ldata->echo_head; | |
807 | __process_echoes(tty); | |
808 | mutex_unlock(&ldata->output_lock); | |
809 | } | |
810 | ||
a88a69c9 | 811 | /** |
98629663 JS |
812 | * add_echo_byte - add a byte to the echo buffer |
813 | * @c: unicode byte to echo | |
814 | * @ldata: n_tty data | |
a88a69c9 | 815 | * |
98629663 | 816 | * Add a character or operation byte to the echo buffer. |
a88a69c9 | 817 | */ |
b9b96b20 | 818 | static inline void add_echo_byte(u8 c, struct n_tty_data *ldata) |
a88a69c9 | 819 | { |
ebec3f8f TH |
820 | *echo_buf_addr(ldata, ldata->echo_head) = c; |
821 | smp_wmb(); /* Matches smp_rmb() in echo_buf(). */ | |
822 | ldata->echo_head++; | |
a88a69c9 JP |
823 | } |
824 | ||
825 | /** | |
98629663 JS |
826 | * echo_move_back_col - add operation to move back a column |
827 | * @ldata: n_tty data | |
a88a69c9 | 828 | * |
98629663 | 829 | * Add an operation to the echo buffer to move back one column. |
a88a69c9 | 830 | */ |
57c94121 | 831 | static void echo_move_back_col(struct n_tty_data *ldata) |
a88a69c9 | 832 | { |
57c94121 JS |
833 | add_echo_byte(ECHO_OP_START, ldata); |
834 | add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); | |
a88a69c9 JP |
835 | } |
836 | ||
837 | /** | |
98629663 JS |
838 | * echo_set_canon_col - add operation to set the canon column |
839 | * @ldata: n_tty data | |
a88a69c9 | 840 | * |
98629663 JS |
841 | * Add an operation to the echo buffer to set the canon column to the current |
842 | * column. | |
a88a69c9 | 843 | */ |
57c94121 | 844 | static void echo_set_canon_col(struct n_tty_data *ldata) |
a88a69c9 | 845 | { |
57c94121 JS |
846 | add_echo_byte(ECHO_OP_START, ldata); |
847 | add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); | |
a88a69c9 JP |
848 | } |
849 | ||
850 | /** | |
98629663 JS |
851 | * echo_erase_tab - add operation to erase a tab |
852 | * @num_chars: number of character columns already used | |
853 | * @after_tab: true if num_chars starts after a previous tab | |
854 | * @ldata: n_tty data | |
855 | * | |
856 | * Add an operation to the echo buffer to erase a tab. | |
857 | * | |
858 | * Called by the eraser function, which knows how many character columns have | |
859 | * been used since either a previous tab or the start of input. This | |
860 | * information will be used later, along with canon column (if applicable), to | |
861 | * go back the correct number of columns. | |
a88a69c9 | 862 | */ |
a88a69c9 | 863 | static void echo_erase_tab(unsigned int num_chars, int after_tab, |
57c94121 | 864 | struct n_tty_data *ldata) |
a88a69c9 | 865 | { |
57c94121 JS |
866 | add_echo_byte(ECHO_OP_START, ldata); |
867 | add_echo_byte(ECHO_OP_ERASE_TAB, ldata); | |
a88a69c9 JP |
868 | |
869 | /* We only need to know this modulo 8 (tab spacing) */ | |
870 | num_chars &= 7; | |
871 | ||
872 | /* Set the high bit as a flag if num_chars is after a previous tab */ | |
873 | if (after_tab) | |
874 | num_chars |= 0x80; | |
300a6204 | 875 | |
57c94121 | 876 | add_echo_byte(num_chars, ldata); |
a88a69c9 JP |
877 | } |
878 | ||
879 | /** | |
98629663 JS |
880 | * echo_char_raw - echo a character raw |
881 | * @c: unicode byte to echo | |
882 | * @ldata: line disc data | |
a88a69c9 | 883 | * |
98629663 JS |
884 | * Echo user input back onto the screen. This must be called only when |
885 | * L_ECHO(tty) is true. Called from the &tty_driver.receive_buf() path. | |
a88a69c9 | 886 | * |
98629663 | 887 | * This variant does not treat control characters specially. |
a88a69c9 | 888 | */ |
b9b96b20 | 889 | static void echo_char_raw(u8 c, struct n_tty_data *ldata) |
a88a69c9 | 890 | { |
a88a69c9 | 891 | if (c == ECHO_OP_START) { |
57c94121 JS |
892 | add_echo_byte(ECHO_OP_START, ldata); |
893 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 894 | } else { |
57c94121 | 895 | add_echo_byte(c, ldata); |
a88a69c9 | 896 | } |
a88a69c9 | 897 | } |
1da177e4 | 898 | |
1da177e4 | 899 | /** |
98629663 JS |
900 | * echo_char - echo a character |
901 | * @c: unicode byte to echo | |
902 | * @tty: terminal device | |
1da177e4 | 903 | * |
98629663 JS |
904 | * Echo user input back onto the screen. This must be called only when |
905 | * L_ECHO(tty) is true. Called from the &tty_driver.receive_buf() path. | |
17b82060 | 906 | * |
98629663 JS |
907 | * This variant tags control characters to be echoed as "^X" (where X is the |
908 | * letter representing the control char). | |
1da177e4 | 909 | */ |
b9b96b20 | 910 | static void echo_char(u8 c, const struct tty_struct *tty) |
1da177e4 | 911 | { |
bddc7152 JS |
912 | struct n_tty_data *ldata = tty->disc_data; |
913 | ||
a88a69c9 | 914 | if (c == ECHO_OP_START) { |
57c94121 JS |
915 | add_echo_byte(ECHO_OP_START, ldata); |
916 | add_echo_byte(ECHO_OP_START, ldata); | |
a88a69c9 | 917 | } else { |
62b26358 | 918 | if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') |
57c94121 JS |
919 | add_echo_byte(ECHO_OP_START, ldata); |
920 | add_echo_byte(c, ldata); | |
a88a69c9 | 921 | } |
1da177e4 LT |
922 | } |
923 | ||
17b82060 | 924 | /** |
98629663 JS |
925 | * finish_erasing - complete erase |
926 | * @ldata: n_tty data | |
17b82060 | 927 | */ |
57c94121 | 928 | static inline void finish_erasing(struct n_tty_data *ldata) |
1da177e4 | 929 | { |
53c5ee2c | 930 | if (ldata->erasing) { |
57c94121 | 931 | echo_char_raw('/', ldata); |
53c5ee2c | 932 | ldata->erasing = 0; |
1da177e4 LT |
933 | } |
934 | } | |
935 | ||
936 | /** | |
98629663 JS |
937 | * eraser - handle erase function |
938 | * @c: character input | |
939 | * @tty: terminal device | |
1da177e4 | 940 | * |
98629663 JS |
941 | * Perform erase and necessary output when an erase character is present in the |
942 | * stream from the driver layer. Handles the complexities of UTF-8 multibyte | |
943 | * symbols. | |
17b82060 | 944 | * |
98629663 JS |
945 | * Locking: n_tty_receive_buf()/producer path: |
946 | * caller holds non-exclusive %termios_rwsem | |
1da177e4 | 947 | */ |
b9b96b20 | 948 | static void eraser(u8 c, const struct tty_struct *tty) |
1da177e4 | 949 | { |
53c5ee2c | 950 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 951 | enum { ERASE, WERASE, KILL } kill_type; |
bc5a5e3f PH |
952 | size_t head; |
953 | size_t cnt; | |
954 | int seen_alnums; | |
1da177e4 | 955 | |
ba2e68ac | 956 | if (ldata->read_head == ldata->canon_head) { |
7e94b1d9 | 957 | /* process_output('\a', tty); */ /* what do you think? */ |
1da177e4 LT |
958 | return; |
959 | } | |
960 | if (c == ERASE_CHAR(tty)) | |
961 | kill_type = ERASE; | |
962 | else if (c == WERASE_CHAR(tty)) | |
963 | kill_type = WERASE; | |
964 | else { | |
965 | if (!L_ECHO(tty)) { | |
ba2e68ac | 966 | ldata->read_head = ldata->canon_head; |
1da177e4 LT |
967 | return; |
968 | } | |
969 | if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { | |
ba2e68ac | 970 | ldata->read_head = ldata->canon_head; |
57c94121 | 971 | finish_erasing(ldata); |
1da177e4 LT |
972 | echo_char(KILL_CHAR(tty), tty); |
973 | /* Add a newline if ECHOK is on and ECHOKE is off. */ | |
974 | if (L_ECHOK(tty)) | |
57c94121 | 975 | echo_char_raw('\n', ldata); |
1da177e4 LT |
976 | return; |
977 | } | |
978 | kill_type = KILL; | |
979 | } | |
980 | ||
981 | seen_alnums = 0; | |
3d63b7e4 | 982 | while (MASK(ldata->read_head) != MASK(ldata->canon_head)) { |
ba2e68ac | 983 | head = ldata->read_head; |
1da177e4 LT |
984 | |
985 | /* erase a single possibly multibyte character */ | |
986 | do { | |
bc5a5e3f PH |
987 | head--; |
988 | c = read_buf(ldata, head); | |
3d63b7e4 TH |
989 | } while (is_continuation(c, tty) && |
990 | MASK(head) != MASK(ldata->canon_head)); | |
1da177e4 LT |
991 | |
992 | /* do not partially erase */ | |
993 | if (is_continuation(c, tty)) | |
994 | break; | |
995 | ||
996 | if (kill_type == WERASE) { | |
997 | /* Equivalent to BSD's ALTWERASE. */ | |
998 | if (isalnum(c) || c == '_') | |
999 | seen_alnums++; | |
1000 | else if (seen_alnums) | |
1001 | break; | |
1002 | } | |
bc5a5e3f | 1003 | cnt = ldata->read_head - head; |
ba2e68ac | 1004 | ldata->read_head = head; |
1da177e4 LT |
1005 | if (L_ECHO(tty)) { |
1006 | if (L_ECHOPRT(tty)) { | |
53c5ee2c | 1007 | if (!ldata->erasing) { |
57c94121 | 1008 | echo_char_raw('\\', ldata); |
53c5ee2c | 1009 | ldata->erasing = 1; |
1da177e4 LT |
1010 | } |
1011 | /* if cnt > 1, output a multi-byte character */ | |
1012 | echo_char(c, tty); | |
1013 | while (--cnt > 0) { | |
bc5a5e3f PH |
1014 | head++; |
1015 | echo_char_raw(read_buf(ldata, head), ldata); | |
57c94121 | 1016 | echo_move_back_col(ldata); |
1da177e4 LT |
1017 | } |
1018 | } else if (kill_type == ERASE && !L_ECHOE(tty)) { | |
1019 | echo_char(ERASE_CHAR(tty), tty); | |
1020 | } else if (c == '\t') { | |
a88a69c9 JP |
1021 | unsigned int num_chars = 0; |
1022 | int after_tab = 0; | |
bc5a5e3f | 1023 | size_t tail = ldata->read_head; |
a88a69c9 JP |
1024 | |
1025 | /* | |
1026 | * Count the columns used for characters | |
1027 | * since the start of input or after a | |
1028 | * previous tab. | |
1029 | * This info is used to go back the correct | |
1030 | * number of columns. | |
1031 | */ | |
3d63b7e4 | 1032 | while (MASK(tail) != MASK(ldata->canon_head)) { |
bc5a5e3f PH |
1033 | tail--; |
1034 | c = read_buf(ldata, tail); | |
a88a69c9 JP |
1035 | if (c == '\t') { |
1036 | after_tab = 1; | |
1037 | break; | |
300a6204 | 1038 | } else if (iscntrl(c)) { |
1da177e4 | 1039 | if (L_ECHOCTL(tty)) |
a88a69c9 JP |
1040 | num_chars += 2; |
1041 | } else if (!is_continuation(c, tty)) { | |
1042 | num_chars++; | |
1043 | } | |
1da177e4 | 1044 | } |
57c94121 | 1045 | echo_erase_tab(num_chars, after_tab, ldata); |
1da177e4 LT |
1046 | } else { |
1047 | if (iscntrl(c) && L_ECHOCTL(tty)) { | |
57c94121 JS |
1048 | echo_char_raw('\b', ldata); |
1049 | echo_char_raw(' ', ldata); | |
1050 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1051 | } |
1052 | if (!iscntrl(c) || L_ECHOCTL(tty)) { | |
57c94121 JS |
1053 | echo_char_raw('\b', ldata); |
1054 | echo_char_raw(' ', ldata); | |
1055 | echo_char_raw('\b', ldata); | |
1da177e4 LT |
1056 | } |
1057 | } | |
1058 | } | |
1059 | if (kill_type == ERASE) | |
1060 | break; | |
1061 | } | |
ba2e68ac | 1062 | if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) |
57c94121 | 1063 | finish_erasing(ldata); |
1da177e4 LT |
1064 | } |
1065 | ||
c66453ce JS |
1066 | |
1067 | static void __isig(int sig, struct tty_struct *tty) | |
1068 | { | |
1069 | struct pid *tty_pgrp = tty_get_pgrp(tty); | |
1070 | if (tty_pgrp) { | |
1071 | kill_pgrp(tty_pgrp, sig, 1); | |
1072 | put_pid(tty_pgrp); | |
1073 | } | |
1074 | } | |
1075 | ||
1da177e4 | 1076 | /** |
98629663 JS |
1077 | * isig - handle the ISIG optio |
1078 | * @sig: signal | |
1079 | * @tty: terminal | |
1da177e4 | 1080 | * |
98629663 JS |
1081 | * Called when a signal is being sent due to terminal input. Called from the |
1082 | * &tty_driver.receive_buf() path, so serialized. | |
17b82060 | 1083 | * |
98629663 JS |
1084 | * Performs input and output flush if !NOFLSH. In this context, the echo |
1085 | * buffer is 'output'. The signal is processed first to alert any current | |
1086 | * readers or writers to discontinue and exit their i/o loops. | |
d2b6f447 | 1087 | * |
98629663 | 1088 | * Locking: %ctrl.lock |
1da177e4 | 1089 | */ |
3b19e032 PH |
1090 | static void isig(int sig, struct tty_struct *tty) |
1091 | { | |
1092 | struct n_tty_data *ldata = tty->disc_data; | |
1093 | ||
1094 | if (L_NOFLSH(tty)) { | |
1095 | /* signal only */ | |
1096 | __isig(sig, tty); | |
1097 | ||
1098 | } else { /* signal and flush */ | |
d2b6f447 PH |
1099 | up_read(&tty->termios_rwsem); |
1100 | down_write(&tty->termios_rwsem); | |
1101 | ||
3b19e032 PH |
1102 | __isig(sig, tty); |
1103 | ||
d2b6f447 PH |
1104 | /* clear echo buffer */ |
1105 | mutex_lock(&ldata->output_lock); | |
1106 | ldata->echo_head = ldata->echo_tail = 0; | |
1107 | ldata->echo_mark = ldata->echo_commit = 0; | |
1108 | mutex_unlock(&ldata->output_lock); | |
1109 | ||
1110 | /* clear output buffer */ | |
1111 | tty_driver_flush_buffer(tty); | |
1112 | ||
1113 | /* clear input buffer */ | |
1114 | reset_buffer_flags(tty->disc_data); | |
1115 | ||
1116 | /* notify pty master of flush */ | |
1117 | if (tty->link) | |
1118 | n_tty_packet_mode_flush(tty); | |
1119 | ||
1120 | up_write(&tty->termios_rwsem); | |
1121 | down_read(&tty->termios_rwsem); | |
1122 | } | |
1da177e4 LT |
1123 | } |
1124 | ||
1125 | /** | |
98629663 JS |
1126 | * n_tty_receive_break - handle break |
1127 | * @tty: terminal | |
1da177e4 | 1128 | * |
98629663 JS |
1129 | * An RS232 break event has been hit in the incoming bitstream. This can cause |
1130 | * a variety of events depending upon the termios settings. | |
1da177e4 | 1131 | * |
98629663 JS |
1132 | * Locking: n_tty_receive_buf()/producer path: |
1133 | * caller holds non-exclusive termios_rwsem | |
6d76bd26 | 1134 | * |
98629663 | 1135 | * Note: may get exclusive %termios_rwsem if flushing input buffer |
1da177e4 | 1136 | */ |
4b293492 | 1137 | static void n_tty_receive_break(struct tty_struct *tty) |
1da177e4 | 1138 | { |
57c94121 JS |
1139 | struct n_tty_data *ldata = tty->disc_data; |
1140 | ||
1da177e4 LT |
1141 | if (I_IGNBRK(tty)) |
1142 | return; | |
1143 | if (I_BRKINT(tty)) { | |
8c985d18 | 1144 | isig(SIGINT, tty); |
1da177e4 LT |
1145 | return; |
1146 | } | |
1147 | if (I_PARMRK(tty)) { | |
57c94121 JS |
1148 | put_tty_queue('\377', ldata); |
1149 | put_tty_queue('\0', ldata); | |
1da177e4 | 1150 | } |
57c94121 | 1151 | put_tty_queue('\0', ldata); |
1da177e4 LT |
1152 | } |
1153 | ||
1154 | /** | |
98629663 JS |
1155 | * n_tty_receive_overrun - handle overrun reporting |
1156 | * @tty: terminal | |
1da177e4 | 1157 | * |
98629663 JS |
1158 | * Data arrived faster than we could process it. While the tty driver has |
1159 | * flagged this the bits that were missed are gone forever. | |
1da177e4 | 1160 | * |
98629663 JS |
1161 | * Called from the receive_buf path so single threaded. Does not need locking |
1162 | * as num_overrun and overrun_time are function private. | |
1da177e4 | 1163 | */ |
5bedcf70 | 1164 | static void n_tty_receive_overrun(const struct tty_struct *tty) |
1da177e4 | 1165 | { |
53c5ee2c | 1166 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1167 | |
53c5ee2c | 1168 | ldata->num_overrun++; |
73276e3a | 1169 | if (time_is_before_jiffies(ldata->overrun_time + HZ)) { |
c3b2b26f | 1170 | tty_warn(tty, "%u input overrun(s)\n", ldata->num_overrun); |
53c5ee2c JS |
1171 | ldata->overrun_time = jiffies; |
1172 | ldata->num_overrun = 0; | |
1da177e4 LT |
1173 | } |
1174 | } | |
1175 | ||
1176 | /** | |
98629663 JS |
1177 | * n_tty_receive_parity_error - error notifier |
1178 | * @tty: terminal device | |
1179 | * @c: character | |
1da177e4 | 1180 | * |
98629663 JS |
1181 | * Process a parity error and queue the right data to indicate the error case |
1182 | * if necessary. | |
6d76bd26 | 1183 | * |
98629663 JS |
1184 | * Locking: n_tty_receive_buf()/producer path: |
1185 | * caller holds non-exclusive %termios_rwsem | |
1da177e4 | 1186 | */ |
5bedcf70 | 1187 | static void n_tty_receive_parity_error(const struct tty_struct *tty, |
b9b96b20 | 1188 | u8 c) |
1da177e4 | 1189 | { |
57c94121 JS |
1190 | struct n_tty_data *ldata = tty->disc_data; |
1191 | ||
66528f90 PH |
1192 | if (I_INPCK(tty)) { |
1193 | if (I_IGNPAR(tty)) | |
1194 | return; | |
1195 | if (I_PARMRK(tty)) { | |
1196 | put_tty_queue('\377', ldata); | |
1197 | put_tty_queue('\0', ldata); | |
1198 | put_tty_queue(c, ldata); | |
1199 | } else | |
1200 | put_tty_queue('\0', ldata); | |
1201 | } else | |
57c94121 | 1202 | put_tty_queue(c, ldata); |
1da177e4 LT |
1203 | } |
1204 | ||
b0ac50be | 1205 | static void |
b9b96b20 | 1206 | n_tty_receive_signal_char(struct tty_struct *tty, int signal, u8 c) |
b0ac50be | 1207 | { |
d2b6f447 | 1208 | isig(signal, tty); |
b0ac50be PH |
1209 | if (I_IXON(tty)) |
1210 | start_tty(tty); | |
1211 | if (L_ECHO(tty)) { | |
1212 | echo_char(c, tty); | |
1213 | commit_echoes(tty); | |
e2613be5 PH |
1214 | } else |
1215 | process_echoes(tty); | |
b0ac50be PH |
1216 | } |
1217 | ||
b9b96b20 | 1218 | static bool n_tty_is_char_flow_ctrl(struct tty_struct *tty, u8 c) |
25e02ba6 IJ |
1219 | { |
1220 | return c == START_CHAR(tty) || c == STOP_CHAR(tty); | |
1221 | } | |
1222 | ||
6bb6fa69 IJ |
1223 | /** |
1224 | * n_tty_receive_char_flow_ctrl - receive flow control chars | |
1225 | * @tty: terminal device | |
1226 | * @c: character | |
1227 | * @lookahead_done: lookahead has processed this character already | |
1228 | * | |
1229 | * Receive and process flow control character actions. | |
1230 | * | |
1231 | * In case lookahead for flow control chars already handled the character in | |
1232 | * advance to the normal receive, the actions are skipped during normal | |
1233 | * receive. | |
1234 | * | |
1235 | * Returns true if @c is consumed as flow-control character, the character | |
1236 | * must not be treated as normal character. | |
1237 | */ | |
b9b96b20 | 1238 | static bool n_tty_receive_char_flow_ctrl(struct tty_struct *tty, u8 c, |
6bb6fa69 | 1239 | bool lookahead_done) |
ec66b8cf | 1240 | { |
25e02ba6 IJ |
1241 | if (!n_tty_is_char_flow_ctrl(tty, c)) |
1242 | return false; | |
1243 | ||
6bb6fa69 IJ |
1244 | if (lookahead_done) |
1245 | return true; | |
1246 | ||
ec66b8cf IJ |
1247 | if (c == START_CHAR(tty)) { |
1248 | start_tty(tty); | |
1249 | process_echoes(tty); | |
1250 | return true; | |
1251 | } | |
ec66b8cf | 1252 | |
25e02ba6 IJ |
1253 | /* STOP_CHAR */ |
1254 | stop_tty(tty); | |
1255 | return true; | |
ec66b8cf IJ |
1256 | } |
1257 | ||
00830407 JSS |
1258 | static void n_tty_receive_handle_newline(struct tty_struct *tty, u8 c) |
1259 | { | |
1260 | struct n_tty_data *ldata = tty->disc_data; | |
1261 | ||
1262 | set_bit(MASK(ldata->read_head), ldata->read_flags); | |
1263 | put_tty_queue(c, ldata); | |
1264 | smp_store_release(&ldata->canon_head, ldata->read_head); | |
1265 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); | |
1266 | wake_up_interruptible_poll(&tty->read_wait, EPOLLIN | EPOLLRDNORM); | |
1267 | } | |
1268 | ||
102dc8aa JSS |
1269 | static bool n_tty_receive_char_canon(struct tty_struct *tty, u8 c) |
1270 | { | |
1271 | struct n_tty_data *ldata = tty->disc_data; | |
1272 | ||
1273 | if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || | |
1274 | (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { | |
1275 | eraser(c, tty); | |
1276 | commit_echoes(tty); | |
1277 | ||
1278 | return true; | |
1279 | } | |
1280 | ||
1281 | if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { | |
1282 | ldata->lnext = 1; | |
1283 | if (L_ECHO(tty)) { | |
1284 | finish_erasing(ldata); | |
1285 | if (L_ECHOCTL(tty)) { | |
1286 | echo_char_raw('^', ldata); | |
1287 | echo_char_raw('\b', ldata); | |
1288 | commit_echoes(tty); | |
1289 | } | |
1290 | } | |
1291 | ||
1292 | return true; | |
1293 | } | |
1294 | ||
1295 | if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { | |
1296 | size_t tail = ldata->canon_head; | |
1297 | ||
1298 | finish_erasing(ldata); | |
1299 | echo_char(c, tty); | |
1300 | echo_char_raw('\n', ldata); | |
1301 | while (MASK(tail) != MASK(ldata->read_head)) { | |
1302 | echo_char(read_buf(ldata, tail), tty); | |
1303 | tail++; | |
1304 | } | |
1305 | commit_echoes(tty); | |
1306 | ||
1307 | return true; | |
1308 | } | |
1309 | ||
1310 | if (c == '\n') { | |
1311 | if (L_ECHO(tty) || L_ECHONL(tty)) { | |
1312 | echo_char_raw('\n', ldata); | |
1313 | commit_echoes(tty); | |
1314 | } | |
00830407 JSS |
1315 | n_tty_receive_handle_newline(tty, c); |
1316 | ||
1317 | return true; | |
102dc8aa JSS |
1318 | } |
1319 | ||
1320 | if (c == EOF_CHAR(tty)) { | |
1321 | c = __DISABLED_CHAR; | |
00830407 JSS |
1322 | n_tty_receive_handle_newline(tty, c); |
1323 | ||
1324 | return true; | |
102dc8aa JSS |
1325 | } |
1326 | ||
1327 | if ((c == EOL_CHAR(tty)) || | |
1328 | (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { | |
1329 | /* | |
1330 | * XXX are EOL_CHAR and EOL2_CHAR echoed?!? | |
1331 | */ | |
1332 | if (L_ECHO(tty)) { | |
1333 | /* Record the column of first canon char. */ | |
1334 | if (ldata->canon_head == ldata->read_head) | |
1335 | echo_set_canon_col(ldata); | |
1336 | echo_char(c, tty); | |
1337 | commit_echoes(tty); | |
1338 | } | |
1339 | /* | |
1340 | * XXX does PARMRK doubling happen for | |
1341 | * EOL_CHAR and EOL2_CHAR? | |
1342 | */ | |
046b44ab | 1343 | if (c == '\377' && I_PARMRK(tty)) |
102dc8aa JSS |
1344 | put_tty_queue(c, ldata); |
1345 | ||
00830407 JSS |
1346 | n_tty_receive_handle_newline(tty, c); |
1347 | ||
102dc8aa JSS |
1348 | return true; |
1349 | } | |
1350 | ||
1351 | return false; | |
1352 | } | |
1353 | ||
b9b96b20 | 1354 | static void n_tty_receive_char_special(struct tty_struct *tty, u8 c, |
6bb6fa69 | 1355 | bool lookahead_done) |
1da177e4 | 1356 | { |
53c5ee2c | 1357 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1358 | |
6bb6fa69 | 1359 | if (I_IXON(tty) && n_tty_receive_char_flow_ctrl(tty, c, lookahead_done)) |
ec66b8cf | 1360 | return; |
575537b3 | 1361 | |
1da177e4 | 1362 | if (L_ISIG(tty)) { |
b0ac50be PH |
1363 | if (c == INTR_CHAR(tty)) { |
1364 | n_tty_receive_signal_char(tty, SIGINT, c); | |
16765365 | 1365 | return; |
b0ac50be PH |
1366 | } else if (c == QUIT_CHAR(tty)) { |
1367 | n_tty_receive_signal_char(tty, SIGQUIT, c); | |
16765365 | 1368 | return; |
b0ac50be PH |
1369 | } else if (c == SUSP_CHAR(tty)) { |
1370 | n_tty_receive_signal_char(tty, SIGTSTP, c); | |
16765365 | 1371 | return; |
1da177e4 LT |
1372 | } |
1373 | } | |
575537b3 | 1374 | |
6e94dbc7 | 1375 | if (tty->flow.stopped && !tty->flow.tco_stopped && I_IXON(tty) && I_IXANY(tty)) { |
855df3c0 PH |
1376 | start_tty(tty); |
1377 | process_echoes(tty); | |
1378 | } | |
1379 | ||
575537b3 JP |
1380 | if (c == '\r') { |
1381 | if (I_IGNCR(tty)) | |
16765365 | 1382 | return; |
575537b3 JP |
1383 | if (I_ICRNL(tty)) |
1384 | c = '\n'; | |
1385 | } else if (c == '\n' && I_INLCR(tty)) | |
1386 | c = '\r'; | |
1387 | ||
102dc8aa JSS |
1388 | if (ldata->icanon && n_tty_receive_char_canon(tty, c)) |
1389 | return; | |
4edf1827 | 1390 | |
acc71bba | 1391 | if (L_ECHO(tty)) { |
57c94121 | 1392 | finish_erasing(ldata); |
1da177e4 | 1393 | if (c == '\n') |
57c94121 | 1394 | echo_char_raw('\n', ldata); |
1da177e4 LT |
1395 | else { |
1396 | /* Record the column of first canon char. */ | |
ba2e68ac | 1397 | if (ldata->canon_head == ldata->read_head) |
57c94121 | 1398 | echo_set_canon_col(ldata); |
1da177e4 LT |
1399 | echo_char(c, tty); |
1400 | } | |
17bd7907 | 1401 | commit_echoes(tty); |
1da177e4 LT |
1402 | } |
1403 | ||
001ba923 | 1404 | /* PARMRK doubling check */ |
046b44ab | 1405 | if (c == '\377' && I_PARMRK(tty)) |
57c94121 | 1406 | put_tty_queue(c, ldata); |
1da177e4 | 1407 | |
57c94121 | 1408 | put_tty_queue(c, ldata); |
4edf1827 | 1409 | } |
1da177e4 | 1410 | |
c66453ce | 1411 | /** |
98629663 JS |
1412 | * n_tty_receive_char - perform processing |
1413 | * @tty: terminal device | |
1414 | * @c: character | |
c66453ce | 1415 | * |
98629663 JS |
1416 | * Process an individual character of input received from the driver. This is |
1417 | * serialized with respect to itself by the rules for the driver above. | |
c66453ce | 1418 | * |
98629663 JS |
1419 | * Locking: n_tty_receive_buf()/producer path: |
1420 | * caller holds non-exclusive %termios_rwsem | |
1421 | * publishes canon_head if canonical mode is active | |
c66453ce | 1422 | */ |
b9b96b20 | 1423 | static void n_tty_receive_char(struct tty_struct *tty, u8 c) |
4b1f79c2 PH |
1424 | { |
1425 | struct n_tty_data *ldata = tty->disc_data; | |
4b1f79c2 | 1426 | |
6e94dbc7 | 1427 | if (tty->flow.stopped && !tty->flow.tco_stopped && I_IXON(tty) && I_IXANY(tty)) { |
e60d27c4 PH |
1428 | start_tty(tty); |
1429 | process_echoes(tty); | |
1430 | } | |
1431 | if (L_ECHO(tty)) { | |
1432 | finish_erasing(ldata); | |
1433 | /* Record the column of first canon char. */ | |
1434 | if (ldata->canon_head == ldata->read_head) | |
1435 | echo_set_canon_col(ldata); | |
1436 | echo_char(c, tty); | |
1437 | commit_echoes(tty); | |
4b1f79c2 | 1438 | } |
001ba923 | 1439 | /* PARMRK doubling check */ |
046b44ab | 1440 | if (c == '\377' && I_PARMRK(tty)) |
e60d27c4 PH |
1441 | put_tty_queue(c, ldata); |
1442 | put_tty_queue(c, ldata); | |
1443 | } | |
4b1f79c2 | 1444 | |
b9b96b20 | 1445 | static void n_tty_receive_char_closing(struct tty_struct *tty, u8 c, |
6bb6fa69 | 1446 | bool lookahead_done) |
ad0cc7ba PH |
1447 | { |
1448 | if (I_ISTRIP(tty)) | |
1449 | c &= 0x7f; | |
1450 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1451 | c = tolower(c); | |
1452 | ||
1453 | if (I_IXON(tty)) { | |
65534736 IJ |
1454 | if (!n_tty_receive_char_flow_ctrl(tty, c, lookahead_done) && |
1455 | tty->flow.stopped && !tty->flow.tco_stopped && I_IXANY(tty) && | |
1456 | c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && | |
1457 | c != SUSP_CHAR(tty)) { | |
ad0cc7ba PH |
1458 | start_tty(tty); |
1459 | process_echoes(tty); | |
1460 | } | |
1461 | } | |
1462 | } | |
1463 | ||
d2f8d7ab | 1464 | static void |
b9b96b20 | 1465 | n_tty_receive_char_flagged(struct tty_struct *tty, u8 c, u8 flag) |
d2f8d7ab | 1466 | { |
d2f8d7ab PH |
1467 | switch (flag) { |
1468 | case TTY_BREAK: | |
1469 | n_tty_receive_break(tty); | |
1470 | break; | |
1471 | case TTY_PARITY: | |
1472 | case TTY_FRAME: | |
1473 | n_tty_receive_parity_error(tty, c); | |
1474 | break; | |
1475 | case TTY_OVERRUN: | |
1476 | n_tty_receive_overrun(tty); | |
1477 | break; | |
1478 | default: | |
b9b96b20 | 1479 | tty_err(tty, "unknown flag %u\n", flag); |
d2f8d7ab PH |
1480 | break; |
1481 | } | |
1482 | } | |
1483 | ||
e60d27c4 | 1484 | static void |
b9b96b20 | 1485 | n_tty_receive_char_lnext(struct tty_struct *tty, u8 c, u8 flag) |
e60d27c4 PH |
1486 | { |
1487 | struct n_tty_data *ldata = tty->disc_data; | |
1488 | ||
1489 | ldata->lnext = 0; | |
1490 | if (likely(flag == TTY_NORMAL)) { | |
1491 | if (I_ISTRIP(tty)) | |
1492 | c &= 0x7f; | |
1493 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1494 | c = tolower(c); | |
95aafe32 | 1495 | n_tty_receive_char(tty, c); |
e60d27c4 PH |
1496 | } else |
1497 | n_tty_receive_char_flagged(tty, c, flag); | |
1498 | } | |
1499 | ||
6bb6fa69 | 1500 | /* Caller must ensure count > 0 */ |
a8d9cd23 | 1501 | static void n_tty_lookahead_flow_ctrl(struct tty_struct *tty, const u8 *cp, |
892bc209 | 1502 | const u8 *fp, size_t count) |
6bb6fa69 IJ |
1503 | { |
1504 | struct n_tty_data *ldata = tty->disc_data; | |
b9b96b20 | 1505 | u8 flag = TTY_NORMAL; |
6bb6fa69 IJ |
1506 | |
1507 | ldata->lookahead_count += count; | |
1508 | ||
1509 | if (!I_IXON(tty)) | |
1510 | return; | |
1511 | ||
1512 | while (count--) { | |
1513 | if (fp) | |
1514 | flag = *fp++; | |
1515 | if (likely(flag == TTY_NORMAL)) | |
1516 | n_tty_receive_char_flow_ctrl(tty, *cp, false); | |
1517 | cp++; | |
1518 | } | |
1519 | } | |
1520 | ||
4a23a4df | 1521 | static void |
a8d9cd23 | 1522 | n_tty_receive_buf_real_raw(const struct tty_struct *tty, const u8 *cp, |
e30364c7 | 1523 | size_t count) |
4a23a4df PH |
1524 | { |
1525 | struct n_tty_data *ldata = tty->disc_data; | |
a84853c5 JSS |
1526 | |
1527 | /* handle buffer wrap-around by a loop */ | |
1528 | for (unsigned int i = 0; i < 2; i++) { | |
1529 | size_t head = MASK(ldata->read_head); | |
1530 | size_t n = min(count, N_TTY_BUF_SIZE - head); | |
1531 | ||
1532 | memcpy(read_buf_addr(ldata, head), cp, n); | |
1533 | ||
1534 | ldata->read_head += n; | |
1535 | cp += n; | |
1536 | count -= n; | |
1537 | } | |
4a23a4df PH |
1538 | } |
1539 | ||
554117bd | 1540 | static void |
892bc209 | 1541 | n_tty_receive_buf_raw(struct tty_struct *tty, const u8 *cp, const u8 *fp, |
e30364c7 | 1542 | size_t count) |
554117bd PH |
1543 | { |
1544 | struct n_tty_data *ldata = tty->disc_data; | |
892bc209 | 1545 | u8 flag = TTY_NORMAL; |
554117bd PH |
1546 | |
1547 | while (count--) { | |
1548 | if (fp) | |
1549 | flag = *fp++; | |
1550 | if (likely(flag == TTY_NORMAL)) | |
1551 | put_tty_queue(*cp++, ldata); | |
1552 | else | |
1553 | n_tty_receive_char_flagged(tty, *cp++, flag); | |
1554 | } | |
1555 | } | |
1556 | ||
ad0cc7ba | 1557 | static void |
892bc209 | 1558 | n_tty_receive_buf_closing(struct tty_struct *tty, const u8 *cp, const u8 *fp, |
e30364c7 | 1559 | size_t count, bool lookahead_done) |
ad0cc7ba | 1560 | { |
b9b96b20 | 1561 | u8 flag = TTY_NORMAL; |
ad0cc7ba PH |
1562 | |
1563 | while (count--) { | |
1564 | if (fp) | |
1565 | flag = *fp++; | |
1566 | if (likely(flag == TTY_NORMAL)) | |
6bb6fa69 | 1567 | n_tty_receive_char_closing(tty, *cp++, lookahead_done); |
ad0cc7ba PH |
1568 | } |
1569 | } | |
1570 | ||
a8d9cd23 | 1571 | static void n_tty_receive_buf_standard(struct tty_struct *tty, const u8 *cp, |
e30364c7 | 1572 | const u8 *fp, size_t count, |
a8d9cd23 | 1573 | bool lookahead_done) |
6baad008 PH |
1574 | { |
1575 | struct n_tty_data *ldata = tty->disc_data; | |
892bc209 | 1576 | u8 flag = TTY_NORMAL; |
6baad008 PH |
1577 | |
1578 | while (count--) { | |
a8d9cd23 | 1579 | u8 c = *cp++; |
3a7d530a | 1580 | |
6baad008 PH |
1581 | if (fp) |
1582 | flag = *fp++; | |
67a620d5 JS |
1583 | |
1584 | if (ldata->lnext) { | |
3a7d530a | 1585 | n_tty_receive_char_lnext(tty, c, flag); |
67a620d5 JS |
1586 | continue; |
1587 | } | |
1588 | ||
e8f2a139 | 1589 | if (unlikely(flag != TTY_NORMAL)) { |
3a7d530a | 1590 | n_tty_receive_char_flagged(tty, c, flag); |
e8f2a139 JS |
1591 | continue; |
1592 | } | |
1593 | ||
1594 | if (I_ISTRIP(tty)) | |
1595 | c &= 0x7f; | |
1596 | if (I_IUCLC(tty) && L_IEXTEN(tty)) | |
1597 | c = tolower(c); | |
1598 | if (L_EXTPROC(tty)) { | |
1599 | put_tty_queue(c, ldata); | |
1600 | continue; | |
1601 | } | |
1602 | ||
1603 | if (test_bit(c, ldata->char_map)) | |
6bb6fa69 | 1604 | n_tty_receive_char_special(tty, c, lookahead_done); |
e8f2a139 JS |
1605 | else |
1606 | n_tty_receive_char(tty, c); | |
6baad008 PH |
1607 | } |
1608 | } | |
1609 | ||
892bc209 | 1610 | static void __receive_buf(struct tty_struct *tty, const u8 *cp, const u8 *fp, |
e30364c7 | 1611 | size_t count) |
1da177e4 | 1612 | { |
53c5ee2c | 1613 | struct n_tty_data *ldata = tty->disc_data; |
a1dd30e9 | 1614 | bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); |
e30364c7 | 1615 | size_t la_count = min(ldata->lookahead_count, count); |
1da177e4 | 1616 | |
4a23a4df | 1617 | if (ldata->real_raw) |
b30a3d39 | 1618 | n_tty_receive_buf_real_raw(tty, cp, count); |
a1dd30e9 | 1619 | else if (ldata->raw || (L_EXTPROC(tty) && !preops)) |
554117bd | 1620 | n_tty_receive_buf_raw(tty, cp, fp, count); |
6bb6fa69 IJ |
1621 | else if (tty->closing && !L_EXTPROC(tty)) { |
1622 | if (la_count > 0) | |
1623 | n_tty_receive_buf_closing(tty, cp, fp, la_count, true); | |
1624 | if (count > la_count) | |
1625 | n_tty_receive_buf_closing(tty, cp, fp, count - la_count, false); | |
1626 | } else { | |
1627 | if (la_count > 0) | |
1628 | n_tty_receive_buf_standard(tty, cp, fp, la_count, true); | |
1629 | if (count > la_count) | |
1630 | n_tty_receive_buf_standard(tty, cp, fp, count - la_count, false); | |
cbfd0340 PH |
1631 | |
1632 | flush_echoes(tty); | |
f34d7a5b AC |
1633 | if (tty->ops->flush_chars) |
1634 | tty->ops->flush_chars(tty); | |
1da177e4 LT |
1635 | } |
1636 | ||
6bb6fa69 IJ |
1637 | ldata->lookahead_count -= la_count; |
1638 | ||
70aca71f PH |
1639 | if (ldata->icanon && !L_EXTPROC(tty)) |
1640 | return; | |
1641 | ||
1642 | /* publish read_head to consumer */ | |
1643 | smp_store_release(&ldata->commit_head, ldata->read_head); | |
1644 | ||
33d71363 | 1645 | if (read_cnt(ldata)) { |
1da177e4 | 1646 | kill_fasync(&tty->fasync, SIGIO, POLL_IN); |
c816b2e6 | 1647 | wake_up_interruptible_poll(&tty->read_wait, EPOLLIN | EPOLLRDNORM); |
1da177e4 | 1648 | } |
1da177e4 LT |
1649 | } |
1650 | ||
fb5ef9e7 | 1651 | /** |
98629663 JS |
1652 | * n_tty_receive_buf_common - process input |
1653 | * @tty: device to receive input | |
1654 | * @cp: input chars | |
1655 | * @fp: flags for each char (if %NULL, all chars are %TTY_NORMAL) | |
1656 | * @count: number of input chars in @cp | |
1657 | * @flow: enable flow control | |
1658 | * | |
1659 | * Called by the terminal driver when a block of characters has been received. | |
1660 | * This function must be called from soft contexts not from interrupt context. | |
1661 | * The driver is responsible for making calls one at a time and in order (or | |
1662 | * using flush_to_ldisc()). | |
1663 | * | |
1664 | * Returns: the # of input chars from @cp which were processed. | |
1665 | * | |
1666 | * In canonical mode, the maximum line length is 4096 chars (including the line | |
1667 | * termination char); lines longer than 4096 chars are truncated. After 4095 | |
1668 | * chars, input data is still processed but not stored. Overflow processing | |
1669 | * ensures the tty can always receive more input until at least one line can be | |
1670 | * read. | |
1671 | * | |
1672 | * In non-canonical mode, the read buffer will only accept 4095 chars; this | |
1673 | * provides the necessary space for a newline char if the input mode is | |
1674 | * switched to canonical. | |
1675 | * | |
1676 | * Note it is possible for the read buffer to _contain_ 4096 chars in | |
1677 | * non-canonical mode: the read buffer could already contain the maximum canon | |
1678 | * line of 4096 chars when the mode is switched to non-canonical. | |
1679 | * | |
1680 | * Locking: n_tty_receive_buf()/producer path: | |
1681 | * claims non-exclusive %termios_rwsem | |
1682 | * publishes commit_head or canon_head | |
fb5ef9e7 | 1683 | */ |
e8161447 | 1684 | static size_t |
892bc209 | 1685 | n_tty_receive_buf_common(struct tty_struct *tty, const u8 *cp, const u8 *fp, |
e30364c7 | 1686 | size_t count, bool flow) |
24a89d1c PH |
1687 | { |
1688 | struct n_tty_data *ldata = tty->disc_data; | |
e30364c7 JSS |
1689 | size_t n, rcvd = 0; |
1690 | int room, overflow; | |
24a89d1c | 1691 | |
9356b535 PH |
1692 | down_read(&tty->termios_rwsem); |
1693 | ||
c96cf923 | 1694 | do { |
70aca71f | 1695 | /* |
06c49f9f PH |
1696 | * When PARMRK is set, each input char may take up to 3 chars |
1697 | * in the read buf; reduce the buffer space avail by 3x | |
70aca71f PH |
1698 | * |
1699 | * If we are doing input canonicalization, and there are no | |
1700 | * pending newlines, let characters through without limit, so | |
1701 | * that erase characters will be handled. Other excess | |
1702 | * characters will be beeped. | |
1703 | * | |
1704 | * paired with store in *_copy_from_read_buf() -- guarantees | |
1705 | * the consumer has loaded the data in read_buf up to the new | |
1706 | * read_tail (so this producer will not overwrite unread data) | |
1707 | */ | |
1708 | size_t tail = smp_load_acquire(&ldata->read_tail); | |
70aca71f | 1709 | |
fb5ef9e7 | 1710 | room = N_TTY_BUF_SIZE - (ldata->read_head - tail); |
70aca71f | 1711 | if (I_PARMRK(tty)) |
7e26c84d | 1712 | room = DIV_ROUND_UP(room, 3); |
fb5ef9e7 PH |
1713 | room--; |
1714 | if (room <= 0) { | |
1715 | overflow = ldata->icanon && ldata->canon_head == tail; | |
1716 | if (overflow && room < 0) | |
1717 | ldata->read_head--; | |
1718 | room = overflow; | |
4903fde8 | 1719 | WRITE_ONCE(ldata->no_room, flow && !room); |
fb5ef9e7 PH |
1720 | } else |
1721 | overflow = 0; | |
70aca71f | 1722 | |
e30364c7 | 1723 | n = min_t(size_t, count, room); |
fb5ef9e7 | 1724 | if (!n) |
19e2ad6a | 1725 | break; |
fb5ef9e7 PH |
1726 | |
1727 | /* ignore parity errors if handling overflow */ | |
1728 | if (!overflow || !fp || *fp != TTY_PARITY) | |
1729 | __receive_buf(tty, cp, fp, n); | |
1730 | ||
19e2ad6a PH |
1731 | cp += n; |
1732 | if (fp) | |
1733 | fp += n; | |
1734 | count -= n; | |
1735 | rcvd += n; | |
c96cf923 | 1736 | } while (!test_bit(TTY_LDISC_CHANGING, &tty->flags)); |
24a89d1c | 1737 | |
19e2ad6a | 1738 | tty->receive_room = room; |
fb5ef9e7 PH |
1739 | |
1740 | /* Unthrottle if handling overflow on pty */ | |
1741 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { | |
1742 | if (overflow) { | |
1743 | tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); | |
1744 | tty_unthrottle_safe(tty); | |
1745 | __tty_set_flow_change(tty, 0); | |
1746 | } | |
1747 | } else | |
1748 | n_tty_check_throttle(tty); | |
1749 | ||
4903fde8 HL |
1750 | if (unlikely(ldata->no_room)) { |
1751 | /* | |
1752 | * Barrier here is to ensure to read the latest read_tail in | |
1753 | * chars_in_buffer() and to make sure that read_tail is not loaded | |
1754 | * before ldata->no_room is set. | |
1755 | */ | |
1756 | smp_mb(); | |
1757 | if (!chars_in_buffer(tty)) | |
1758 | n_tty_kick_worker(tty); | |
1759 | } | |
1760 | ||
9356b535 PH |
1761 | up_read(&tty->termios_rwsem); |
1762 | ||
19e2ad6a | 1763 | return rcvd; |
24a89d1c PH |
1764 | } |
1765 | ||
a8d9cd23 | 1766 | static void n_tty_receive_buf(struct tty_struct *tty, const u8 *cp, |
892bc209 | 1767 | const u8 *fp, size_t count) |
5c32d123 | 1768 | { |
0d029ab8 | 1769 | n_tty_receive_buf_common(tty, cp, fp, count, false); |
5c32d123 PH |
1770 | } |
1771 | ||
a8d9cd23 | 1772 | static size_t n_tty_receive_buf2(struct tty_struct *tty, const u8 *cp, |
892bc209 | 1773 | const u8 *fp, size_t count) |
5c32d123 | 1774 | { |
0d029ab8 | 1775 | return n_tty_receive_buf_common(tty, cp, fp, count, true); |
5c32d123 PH |
1776 | } |
1777 | ||
1da177e4 | 1778 | /** |
98629663 JS |
1779 | * n_tty_set_termios - termios data changed |
1780 | * @tty: terminal | |
1781 | * @old: previous data | |
1da177e4 | 1782 | * |
98629663 JS |
1783 | * Called by the tty layer when the user changes termios flags so that the line |
1784 | * discipline can plan ahead. This function cannot sleep and is protected from | |
1785 | * re-entry by the tty layer. The user is guaranteed that this function will | |
1786 | * not be re-entered or in progress when the ldisc is closed. | |
17b82060 | 1787 | * |
98629663 | 1788 | * Locking: Caller holds @tty->termios_rwsem |
1da177e4 | 1789 | */ |
8b7d2d95 | 1790 | static void n_tty_set_termios(struct tty_struct *tty, const struct ktermios *old) |
1da177e4 | 1791 | { |
53c5ee2c | 1792 | struct n_tty_data *ldata = tty->disc_data; |
47afa7a5 | 1793 | |
966031f3 | 1794 | if (!old || (old->c_lflag ^ tty->termios.c_lflag) & (ICANON | EXTPROC)) { |
3fe780b3 | 1795 | bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); |
4d0ed182 PH |
1796 | ldata->line_start = ldata->read_tail; |
1797 | if (!L_ICANON(tty) || !read_cnt(ldata)) { | |
1798 | ldata->canon_head = ldata->read_tail; | |
1799 | ldata->push = 0; | |
1800 | } else { | |
819287f0 | 1801 | set_bit(MASK(ldata->read_head - 1), ldata->read_flags); |
4d0ed182 PH |
1802 | ldata->canon_head = ldata->read_head; |
1803 | ldata->push = 1; | |
1804 | } | |
70aca71f | 1805 | ldata->commit_head = ldata->read_head; |
53c5ee2c | 1806 | ldata->erasing = 0; |
6f9b028a | 1807 | ldata->lnext = 0; |
47afa7a5 AC |
1808 | } |
1809 | ||
53c5ee2c | 1810 | ldata->icanon = (L_ICANON(tty) != 0); |
582f5590 | 1811 | |
1da177e4 LT |
1812 | if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || |
1813 | I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || | |
1814 | I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || | |
1815 | I_PARMRK(tty)) { | |
1bb9d562 | 1816 | bitmap_zero(ldata->char_map, 256); |
1da177e4 LT |
1817 | |
1818 | if (I_IGNCR(tty) || I_ICRNL(tty)) | |
1bb9d562 | 1819 | set_bit('\r', ldata->char_map); |
1da177e4 | 1820 | if (I_INLCR(tty)) |
1bb9d562 | 1821 | set_bit('\n', ldata->char_map); |
1da177e4 LT |
1822 | |
1823 | if (L_ICANON(tty)) { | |
1bb9d562 PH |
1824 | set_bit(ERASE_CHAR(tty), ldata->char_map); |
1825 | set_bit(KILL_CHAR(tty), ldata->char_map); | |
1826 | set_bit(EOF_CHAR(tty), ldata->char_map); | |
1827 | set_bit('\n', ldata->char_map); | |
1828 | set_bit(EOL_CHAR(tty), ldata->char_map); | |
1da177e4 | 1829 | if (L_IEXTEN(tty)) { |
1bb9d562 PH |
1830 | set_bit(WERASE_CHAR(tty), ldata->char_map); |
1831 | set_bit(LNEXT_CHAR(tty), ldata->char_map); | |
1832 | set_bit(EOL2_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1833 | if (L_ECHO(tty)) |
1834 | set_bit(REPRINT_CHAR(tty), | |
1bb9d562 | 1835 | ldata->char_map); |
1da177e4 LT |
1836 | } |
1837 | } | |
1838 | if (I_IXON(tty)) { | |
1bb9d562 PH |
1839 | set_bit(START_CHAR(tty), ldata->char_map); |
1840 | set_bit(STOP_CHAR(tty), ldata->char_map); | |
1da177e4 LT |
1841 | } |
1842 | if (L_ISIG(tty)) { | |
1bb9d562 PH |
1843 | set_bit(INTR_CHAR(tty), ldata->char_map); |
1844 | set_bit(QUIT_CHAR(tty), ldata->char_map); | |
1845 | set_bit(SUSP_CHAR(tty), ldata->char_map); | |
1da177e4 | 1846 | } |
1bb9d562 | 1847 | clear_bit(__DISABLED_CHAR, ldata->char_map); |
53c5ee2c JS |
1848 | ldata->raw = 0; |
1849 | ldata->real_raw = 0; | |
1da177e4 | 1850 | } else { |
53c5ee2c | 1851 | ldata->raw = 1; |
1da177e4 LT |
1852 | if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && |
1853 | (I_IGNPAR(tty) || !I_INPCK(tty)) && | |
1854 | (tty->driver->flags & TTY_DRIVER_REAL_RAW)) | |
53c5ee2c | 1855 | ldata->real_raw = 1; |
1da177e4 | 1856 | else |
53c5ee2c | 1857 | ldata->real_raw = 0; |
1da177e4 | 1858 | } |
dab73b4e WY |
1859 | /* |
1860 | * Fix tty hang when I_IXON(tty) is cleared, but the tty | |
1861 | * been stopped by STOP_CHAR(tty) before it. | |
1862 | */ | |
6e94dbc7 | 1863 | if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow.tco_stopped) { |
dab73b4e | 1864 | start_tty(tty); |
e2613be5 PH |
1865 | process_echoes(tty); |
1866 | } | |
dab73b4e | 1867 | |
f34d7a5b | 1868 | /* The termios change make the tty ready for I/O */ |
e81107d4 KT |
1869 | wake_up_interruptible(&tty->write_wait); |
1870 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1871 | } |
1872 | ||
1873 | /** | |
98629663 JS |
1874 | * n_tty_close - close the ldisc for this tty |
1875 | * @tty: device | |
1da177e4 | 1876 | * |
98629663 JS |
1877 | * Called from the terminal layer when this line discipline is being shut down, |
1878 | * either because of a close or becsuse of a discipline change. The function | |
1879 | * will not be called while other ldisc methods are in progress. | |
1da177e4 | 1880 | */ |
1da177e4 LT |
1881 | static void n_tty_close(struct tty_struct *tty) |
1882 | { | |
70ece7a7 JS |
1883 | struct n_tty_data *ldata = tty->disc_data; |
1884 | ||
79901317 PH |
1885 | if (tty->link) |
1886 | n_tty_packet_mode_flush(tty); | |
1887 | ||
c9cd57bf | 1888 | down_write(&tty->termios_rwsem); |
20bafb3d | 1889 | vfree(ldata); |
70ece7a7 | 1890 | tty->disc_data = NULL; |
c9cd57bf | 1891 | up_write(&tty->termios_rwsem); |
1da177e4 LT |
1892 | } |
1893 | ||
1894 | /** | |
98629663 JS |
1895 | * n_tty_open - open an ldisc |
1896 | * @tty: terminal to open | |
1da177e4 | 1897 | * |
98629663 JS |
1898 | * Called when this line discipline is being attached to the terminal device. |
1899 | * Can sleep. Called serialized so that no other events will occur in parallel. | |
1900 | * No further open will occur until a close. | |
1da177e4 | 1901 | */ |
1da177e4 LT |
1902 | static int n_tty_open(struct tty_struct *tty) |
1903 | { | |
70ece7a7 JS |
1904 | struct n_tty_data *ldata; |
1905 | ||
20bafb3d | 1906 | /* Currently a malloc failure here can panic */ |
ebec3f8f | 1907 | ldata = vzalloc(sizeof(*ldata)); |
70ece7a7 | 1908 | if (!ldata) |
ebec3f8f | 1909 | return -ENOMEM; |
70ece7a7 | 1910 | |
53c5ee2c | 1911 | ldata->overrun_time = jiffies; |
bddc7152 JS |
1912 | mutex_init(&ldata->atomic_read_lock); |
1913 | mutex_init(&ldata->output_lock); | |
53c5ee2c | 1914 | |
70ece7a7 | 1915 | tty->disc_data = ldata; |
1da177e4 | 1916 | tty->closing = 0; |
b66f4fa5 PH |
1917 | /* indicate buffer work may resume */ |
1918 | clear_bit(TTY_LDISC_HALTED, &tty->flags); | |
1919 | n_tty_set_termios(tty, NULL); | |
1920 | tty_unthrottle(tty); | |
1da177e4 LT |
1921 | return 0; |
1922 | } | |
1923 | ||
5bedcf70 | 1924 | static inline int input_available_p(const struct tty_struct *tty, int poll) |
1da177e4 | 1925 | { |
5bedcf70 | 1926 | const struct n_tty_data *ldata = tty->disc_data; |
a5934804 | 1927 | int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; |
53c5ee2c | 1928 | |
25e8d0ed PH |
1929 | if (ldata->icanon && !L_EXTPROC(tty)) |
1930 | return ldata->canon_head != ldata->read_tail; | |
1931 | else | |
70aca71f | 1932 | return ldata->commit_head - ldata->read_tail >= amt; |
1da177e4 LT |
1933 | } |
1934 | ||
1935 | /** | |
98629663 JS |
1936 | * copy_from_read_buf - copy read data directly |
1937 | * @tty: terminal device | |
1938 | * @kbp: data | |
1939 | * @nr: size of data | |
1da177e4 | 1940 | * |
98629663 JS |
1941 | * Helper function to speed up n_tty_read(). It is only called when %ICANON is |
1942 | * off; it copies characters straight from the tty queue. | |
1da177e4 | 1943 | * |
98629663 JS |
1944 | * Returns: true if it successfully copied data, but there is still more data |
1945 | * to be had. | |
15ea8ae8 | 1946 | * |
98629663 JS |
1947 | * Locking: |
1948 | * * called under the @ldata->atomic_read_lock sem | |
1949 | * * n_tty_read()/consumer path: | |
1950 | * caller holds non-exclusive %termios_rwsem; | |
6d76bd26 | 1951 | * read_tail published |
1da177e4 | 1952 | */ |
e30364c7 JSS |
1953 | static bool copy_from_read_buf(const struct tty_struct *tty, u8 **kbp, |
1954 | size_t *nr) | |
1da177e4 LT |
1955 | |
1956 | { | |
53c5ee2c | 1957 | struct n_tty_data *ldata = tty->disc_data; |
1da177e4 | 1958 | size_t n; |
3fa10cc8 | 1959 | bool is_eof; |
70aca71f | 1960 | size_t head = smp_load_acquire(&ldata->commit_head); |
819287f0 | 1961 | size_t tail = MASK(ldata->read_tail); |
1da177e4 | 1962 | |
72369f2d | 1963 | n = min3(head - ldata->read_tail, N_TTY_BUF_SIZE - tail, *nr); |
c2b0fb9f JSS |
1964 | if (!n) |
1965 | return false; | |
1966 | ||
1967 | u8 *from = read_buf_addr(ldata, tail); | |
1968 | memcpy(*kbp, from, n); | |
1969 | is_eof = n == 1 && *from == EOF_CHAR(tty); | |
1970 | tty_audit_add_data(tty, from, n); | |
1971 | zero_buffer(tty, from, n); | |
1972 | smp_store_release(&ldata->read_tail, ldata->read_tail + n); | |
1973 | ||
1974 | /* Turn single EOF into zero-length read */ | |
1975 | if (L_EXTPROC(tty) && ldata->icanon && is_eof && | |
1976 | head == ldata->read_tail) | |
1977 | return false; | |
1978 | ||
1979 | *kbp += n; | |
1980 | *nr -= n; | |
1981 | ||
1982 | /* If we have more to copy, let the caller know */ | |
1983 | return head != ldata->read_tail; | |
1da177e4 LT |
1984 | } |
1985 | ||
88bb0de3 | 1986 | /** |
98629663 JS |
1987 | * canon_copy_from_read_buf - copy read data in canonical mode |
1988 | * @tty: terminal device | |
1989 | * @kbp: data | |
1990 | * @nr: size of data | |
1991 | * | |
1992 | * Helper function for n_tty_read(). It is only called when %ICANON is on; it | |
1993 | * copies one line of input up to and including the line-delimiting character | |
1994 | * into the result buffer. | |
1995 | * | |
1996 | * Note: When termios is changed from non-canonical to canonical mode and the | |
1997 | * read buffer contains data, n_tty_set_termios() simulates an EOF push (as if | |
1998 | * C-d were input) _without_ the %DISABLED_CHAR in the buffer. This causes data | |
1999 | * already processed as input to be immediately available as input although a | |
2000 | * newline has not been received. | |
2001 | * | |
2002 | * Locking: | |
2003 | * * called under the %atomic_read_lock mutex | |
2004 | * * n_tty_read()/consumer path: | |
2005 | * caller holds non-exclusive %termios_rwsem; | |
2006 | * read_tail published | |
88bb0de3 | 2007 | */ |
e30364c7 | 2008 | static bool canon_copy_from_read_buf(const struct tty_struct *tty, u8 **kbp, |
64a69892 | 2009 | size_t *nr) |
88bb0de3 PH |
2010 | { |
2011 | struct n_tty_data *ldata = tty->disc_data; | |
32f13521 | 2012 | size_t n, size, more, c; |
bc5a5e3f | 2013 | size_t eol; |
d7fe75cb | 2014 | size_t tail, canon_head; |
3b830a9c | 2015 | int found = 0; |
88bb0de3 PH |
2016 | |
2017 | /* N.B. avoid overrun if nr == 0 */ | |
ac8f3bf8 | 2018 | if (!*nr) |
d7fe75cb | 2019 | return false; |
88bb0de3 | 2020 | |
d7fe75cb | 2021 | canon_head = smp_load_acquire(&ldata->canon_head); |
35930307 | 2022 | n = min(*nr, canon_head - ldata->read_tail); |
ac8f3bf8 | 2023 | |
819287f0 | 2024 | tail = MASK(ldata->read_tail); |
32f13521 PH |
2025 | size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); |
2026 | ||
bc5a5e3f | 2027 | n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", |
32f13521 PH |
2028 | __func__, *nr, tail, n, size); |
2029 | ||
2030 | eol = find_next_bit(ldata->read_flags, size, tail); | |
2031 | more = n - (size - tail); | |
2032 | if (eol == N_TTY_BUF_SIZE && more) { | |
2033 | /* scan wrapped without finding set bit */ | |
b5c7e7ec | 2034 | eol = find_first_bit(ldata->read_flags, more); |
b985e9e3 PH |
2035 | found = eol != more; |
2036 | } else | |
2037 | found = eol != size; | |
32f13521 | 2038 | |
c77569d2 | 2039 | n = eol - tail; |
da555db6 MT |
2040 | if (n > N_TTY_BUF_SIZE) |
2041 | n += N_TTY_BUF_SIZE; | |
ac8f3bf8 | 2042 | c = n + found; |
32f13521 | 2043 | |
35930307 | 2044 | if (!found || read_buf(ldata, eol) != __DISABLED_CHAR) |
ac8f3bf8 | 2045 | n = c; |
32f13521 | 2046 | |
679e7c29 PH |
2047 | n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu tail:%zu more:%zu\n", |
2048 | __func__, eol, found, n, c, tail, more); | |
32f13521 | 2049 | |
3b830a9c LT |
2050 | tty_copy(tty, *kbp, tail, n); |
2051 | *kbp += n; | |
32f13521 PH |
2052 | *nr -= n; |
2053 | ||
a73d3d69 | 2054 | if (found) |
6d76bd26 | 2055 | clear_bit(eol, ldata->read_flags); |
70aca71f | 2056 | smp_store_release(&ldata->read_tail, ldata->read_tail + c); |
88bb0de3 | 2057 | |
40d5e090 | 2058 | if (found) { |
4d0ed182 PH |
2059 | if (!ldata->push) |
2060 | ldata->line_start = ldata->read_tail; | |
2061 | else | |
2062 | ldata->push = 0; | |
b50819f4 | 2063 | tty_audit_push(); |
d7fe75cb | 2064 | return false; |
40d5e090 | 2065 | } |
d7fe75cb LT |
2066 | |
2067 | /* No EOL found - do a continuation retry if there is more data */ | |
2068 | return ldata->read_tail != canon_head; | |
88bb0de3 PH |
2069 | } |
2070 | ||
65a8b287 DG |
2071 | /* |
2072 | * If we finished a read at the exact location of an | |
2073 | * EOF (special EOL character that's a __DISABLED_CHAR) | |
2074 | * in the stream, silently eat the EOF. | |
2075 | */ | |
32042446 | 2076 | static void canon_skip_eof(struct n_tty_data *ldata) |
65a8b287 | 2077 | { |
65a8b287 DG |
2078 | size_t tail, canon_head; |
2079 | ||
2080 | canon_head = smp_load_acquire(&ldata->canon_head); | |
2081 | tail = ldata->read_tail; | |
2082 | ||
2083 | // No data? | |
2084 | if (tail == canon_head) | |
2085 | return; | |
2086 | ||
2087 | // See if the tail position is EOF in the circular buffer | |
2088 | tail &= (N_TTY_BUF_SIZE - 1); | |
2089 | if (!test_bit(tail, ldata->read_flags)) | |
2090 | return; | |
2091 | if (read_buf(ldata, tail) != __DISABLED_CHAR) | |
2092 | return; | |
2093 | ||
2094 | // Clear the EOL bit, skip the EOF char. | |
2095 | clear_bit(tail, ldata->read_flags); | |
2096 | smp_store_release(&ldata->read_tail, ldata->read_tail + 1); | |
2097 | } | |
2098 | ||
1da177e4 | 2099 | /** |
98629663 JS |
2100 | * job_control - check job control |
2101 | * @tty: tty | |
2102 | * @file: file handle | |
2103 | * | |
2104 | * Perform job control management checks on this @file/@tty descriptor and if | |
2105 | * appropriate send any needed signals and return a negative error code if | |
2106 | * action should be taken. | |
2107 | * | |
2108 | * Locking: | |
2109 | * * redirected write test is safe | |
2110 | * * current->signal->tty check is safe | |
2111 | * * ctrl.lock to safely reference @tty->ctrl.pgrp | |
1da177e4 | 2112 | */ |
1da177e4 LT |
2113 | static int job_control(struct tty_struct *tty, struct file *file) |
2114 | { | |
2115 | /* Job control check -- must be done at start and after | |
2116 | every sleep (POSIX.1 7.1.1.4). */ | |
2117 | /* NOTE: not yet done after every sleep pending a thorough | |
2118 | check of the logic of this change. -- jlc */ | |
2119 | /* don't stop on /dev/console */ | |
9f12e37c | 2120 | if (file->f_op->write_iter == redirected_tty_write) |
01a5e440 PH |
2121 | return 0; |
2122 | ||
2812d9e9 | 2123 | return __tty_check_change(tty, SIGTTIN); |
1da177e4 | 2124 | } |
4edf1827 | 2125 | |
1da177e4 LT |
2126 | |
2127 | /** | |
98629663 JS |
2128 | * n_tty_read - read function for tty |
2129 | * @tty: tty device | |
2130 | * @file: file object | |
2131 | * @kbuf: kernelspace buffer pointer | |
2132 | * @nr: size of I/O | |
2133 | * @cookie: if non-%NULL, this is a continuation read | |
2134 | * @offset: where to continue reading from (unused in n_tty) | |
2135 | * | |
2136 | * Perform reads for the line discipline. We are guaranteed that the line | |
2137 | * discipline will not be closed under us but we may get multiple parallel | |
2138 | * readers and must handle this ourselves. We may also get a hangup. Always | |
2139 | * called in user context, may sleep. | |
2140 | * | |
2141 | * This code must be sure never to sleep through a hangup. | |
2142 | * | |
2143 | * Locking: n_tty_read()/consumer path: | |
2144 | * claims non-exclusive termios_rwsem; | |
2145 | * publishes read_tail | |
1da177e4 | 2146 | */ |
49b8220c JSS |
2147 | static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, u8 *kbuf, |
2148 | size_t nr, void **cookie, unsigned long offset) | |
1da177e4 | 2149 | { |
53c5ee2c | 2150 | struct n_tty_data *ldata = tty->disc_data; |
49b8220c | 2151 | u8 *kb = kbuf; |
97d9e28d | 2152 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
1da177e4 | 2153 | int minimum, time; |
4a2ad266 | 2154 | ssize_t retval; |
1da177e4 | 2155 | long timeout; |
64d608db | 2156 | bool packet; |
947d66b6 | 2157 | size_t old_tail; |
1da177e4 | 2158 | |
15ea8ae8 LT |
2159 | /* |
2160 | * Is this a continuation of a read started earler? | |
2161 | * | |
2162 | * If so, we still hold the atomic_read_lock and the | |
2163 | * termios_rwsem, and can just continue to copy data. | |
2164 | */ | |
2165 | if (*cookie) { | |
d7fe75cb | 2166 | if (ldata->icanon && !L_EXTPROC(tty)) { |
65a8b287 DG |
2167 | /* |
2168 | * If we have filled the user buffer, see | |
2169 | * if we should skip an EOF character before | |
2170 | * releasing the lock and returning done. | |
2171 | */ | |
2172 | if (!nr) | |
32042446 | 2173 | canon_skip_eof(ldata); |
65a8b287 | 2174 | else if (canon_copy_from_read_buf(tty, &kb, &nr)) |
d7fe75cb LT |
2175 | return kb - kbuf; |
2176 | } else { | |
2177 | if (copy_from_read_buf(tty, &kb, &nr)) | |
2178 | return kb - kbuf; | |
2179 | } | |
15ea8ae8 LT |
2180 | |
2181 | /* No more data - release locks and stop retries */ | |
2182 | n_tty_kick_worker(tty); | |
2183 | n_tty_check_unthrottle(tty); | |
2184 | up_read(&tty->termios_rwsem); | |
2185 | mutex_unlock(&ldata->atomic_read_lock); | |
2186 | *cookie = NULL; | |
2187 | return kb - kbuf; | |
2188 | } | |
2189 | ||
4a2ad266 JSS |
2190 | retval = job_control(tty, file); |
2191 | if (retval < 0) | |
2192 | return retval; | |
4edf1827 | 2193 | |
aefceaf4 PH |
2194 | /* |
2195 | * Internal serialization of reads. | |
2196 | */ | |
2197 | if (file->f_flags & O_NONBLOCK) { | |
2198 | if (!mutex_trylock(&ldata->atomic_read_lock)) | |
2199 | return -EAGAIN; | |
2200 | } else { | |
2201 | if (mutex_lock_interruptible(&ldata->atomic_read_lock)) | |
2202 | return -ERESTARTSYS; | |
2203 | } | |
2204 | ||
9356b535 PH |
2205 | down_read(&tty->termios_rwsem); |
2206 | ||
1da177e4 LT |
2207 | minimum = time = 0; |
2208 | timeout = MAX_SCHEDULE_TIMEOUT; | |
53c5ee2c | 2209 | if (!ldata->icanon) { |
1da177e4 LT |
2210 | minimum = MIN_CHAR(tty); |
2211 | if (minimum) { | |
a6e54319 | 2212 | time = (HZ / 10) * TIME_CHAR(tty); |
1da177e4 | 2213 | } else { |
a6e54319 | 2214 | timeout = (HZ / 10) * TIME_CHAR(tty); |
33d71363 | 2215 | minimum = 1; |
1da177e4 LT |
2216 | } |
2217 | } | |
2218 | ||
64d608db | 2219 | packet = tty->ctrl.packet; |
947d66b6 | 2220 | old_tail = ldata->read_tail; |
1da177e4 LT |
2221 | |
2222 | add_wait_queue(&tty->read_wait, &wait); | |
1da177e4 LT |
2223 | while (nr) { |
2224 | /* First test for status change. */ | |
64d608db | 2225 | if (packet && tty->link->ctrl.pktstatus) { |
b9b96b20 | 2226 | u8 cs; |
3b830a9c | 2227 | if (kb != kbuf) |
1da177e4 | 2228 | break; |
64d608db JS |
2229 | spin_lock_irq(&tty->link->ctrl.lock); |
2230 | cs = tty->link->ctrl.pktstatus; | |
2231 | tty->link->ctrl.pktstatus = 0; | |
2232 | spin_unlock_irq(&tty->link->ctrl.lock); | |
3b830a9c | 2233 | *kb++ = cs; |
1da177e4 LT |
2234 | nr--; |
2235 | break; | |
2236 | } | |
4edf1827 | 2237 | |
1da177e4 | 2238 | if (!input_available_p(tty, 0)) { |
52bce7f8 | 2239 | up_read(&tty->termios_rwsem); |
0f40fbbc BB |
2240 | tty_buffer_flush_work(tty->port); |
2241 | down_read(&tty->termios_rwsem); | |
2242 | if (!input_available_p(tty, 0)) { | |
2243 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { | |
2244 | retval = -EIO; | |
2245 | break; | |
2246 | } | |
2247 | if (tty_hung_up_p(file)) | |
2248 | break; | |
28b0f8a6 TH |
2249 | /* |
2250 | * Abort readers for ttys which never actually | |
2251 | * get hung up. See __tty_hangup(). | |
2252 | */ | |
2253 | if (test_bit(TTY_HUPPING, &tty->flags)) | |
2254 | break; | |
0f40fbbc BB |
2255 | if (!timeout) |
2256 | break; | |
c96cf923 | 2257 | if (tty_io_nonblock(tty, file)) { |
0f40fbbc BB |
2258 | retval = -EAGAIN; |
2259 | break; | |
2260 | } | |
2261 | if (signal_pending(current)) { | |
2262 | retval = -ERESTARTSYS; | |
2263 | break; | |
2264 | } | |
2265 | up_read(&tty->termios_rwsem); | |
9356b535 | 2266 | |
0f40fbbc BB |
2267 | timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, |
2268 | timeout); | |
9356b535 | 2269 | |
0f40fbbc BB |
2270 | down_read(&tty->termios_rwsem); |
2271 | continue; | |
2272 | } | |
1da177e4 LT |
2273 | } |
2274 | ||
53c5ee2c | 2275 | if (ldata->icanon && !L_EXTPROC(tty)) { |
d7fe75cb LT |
2276 | if (canon_copy_from_read_buf(tty, &kb, &nr)) |
2277 | goto more_to_be_read; | |
1da177e4 | 2278 | } else { |
95ea90db | 2279 | /* Deal with packet mode. */ |
3b830a9c LT |
2280 | if (packet && kb == kbuf) { |
2281 | *kb++ = TIOCPKT_DATA; | |
95ea90db PH |
2282 | nr--; |
2283 | } | |
2284 | ||
15ea8ae8 LT |
2285 | /* |
2286 | * Copy data, and if there is more to be had | |
2287 | * and we have nothing more to wait for, then | |
2288 | * let's mark us for retries. | |
2289 | * | |
2290 | * NOTE! We return here with both the termios_sem | |
2291 | * and atomic_read_lock still held, the retries | |
2292 | * will release them when done. | |
2293 | */ | |
2294 | if (copy_from_read_buf(tty, &kb, &nr) && kb - kbuf >= minimum) { | |
d7fe75cb | 2295 | more_to_be_read: |
15ea8ae8 LT |
2296 | remove_wait_queue(&tty->read_wait, &wait); |
2297 | *cookie = cookie; | |
2298 | return kb - kbuf; | |
1da177e4 LT |
2299 | } |
2300 | } | |
2301 | ||
6367ca72 | 2302 | n_tty_check_unthrottle(tty); |
1da177e4 | 2303 | |
3b830a9c | 2304 | if (kb - kbuf >= minimum) |
1da177e4 LT |
2305 | break; |
2306 | if (time) | |
2307 | timeout = time; | |
2308 | } | |
4903fde8 HL |
2309 | if (old_tail != ldata->read_tail) { |
2310 | /* | |
2311 | * Make sure no_room is not read in n_tty_kick_worker() | |
2312 | * before setting ldata->read_tail in copy_from_read_buf(). | |
2313 | */ | |
2314 | smp_mb(); | |
2c5dc464 | 2315 | n_tty_kick_worker(tty); |
4903fde8 | 2316 | } |
42458f41 PH |
2317 | up_read(&tty->termios_rwsem); |
2318 | ||
1da177e4 | 2319 | remove_wait_queue(&tty->read_wait, &wait); |
aebf0453 PH |
2320 | mutex_unlock(&ldata->atomic_read_lock); |
2321 | ||
3b830a9c LT |
2322 | if (kb - kbuf) |
2323 | retval = kb - kbuf; | |
1da177e4 LT |
2324 | |
2325 | return retval; | |
2326 | } | |
2327 | ||
2328 | /** | |
98629663 JS |
2329 | * n_tty_write - write function for tty |
2330 | * @tty: tty device | |
2331 | * @file: file object | |
2332 | * @buf: userspace buffer pointer | |
2333 | * @nr: size of I/O | |
2334 | * | |
2335 | * Write function of the terminal device. This is serialized with respect to | |
2336 | * other write callers but not to termios changes, reads and other such events. | |
2337 | * Since the receive code will echo characters, thus calling driver write | |
2338 | * methods, the %output_lock is used in the output processing functions called | |
2339 | * here as well as in the echo processing function to protect the column state | |
2340 | * and space left in the buffer. | |
2341 | * | |
2342 | * This code must be sure never to sleep through a hangup. | |
2343 | * | |
2344 | * Locking: output_lock to protect column state and space left | |
2345 | * (note that the process_output*() functions take this lock themselves) | |
1da177e4 | 2346 | */ |
4edf1827 | 2347 | |
11a96d18 | 2348 | static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, |
49b8220c | 2349 | const u8 *buf, size_t nr) |
1da177e4 | 2350 | { |
49b8220c | 2351 | const u8 *b = buf; |
97d9e28d | 2352 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
68d90d5f | 2353 | ssize_t num, retval = 0; |
1da177e4 LT |
2354 | |
2355 | /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ | |
9f12e37c | 2356 | if (L_TOSTOP(tty) && file->f_op->write_iter != redirected_tty_write) { |
1da177e4 LT |
2357 | retval = tty_check_change(tty); |
2358 | if (retval) | |
2359 | return retval; | |
2360 | } | |
2361 | ||
9356b535 PH |
2362 | down_read(&tty->termios_rwsem); |
2363 | ||
a88a69c9 JP |
2364 | /* Write out any echoed characters that are still pending */ |
2365 | process_echoes(tty); | |
300a6204 | 2366 | |
1da177e4 LT |
2367 | add_wait_queue(&tty->write_wait, &wait); |
2368 | while (1) { | |
1da177e4 LT |
2369 | if (signal_pending(current)) { |
2370 | retval = -ERESTARTSYS; | |
2371 | break; | |
2372 | } | |
2373 | if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { | |
2374 | retval = -EIO; | |
2375 | break; | |
2376 | } | |
582f5590 | 2377 | if (O_OPOST(tty)) { |
1da177e4 | 2378 | while (nr > 0) { |
68d90d5f | 2379 | num = process_output_block(tty, b, nr); |
1da177e4 LT |
2380 | if (num < 0) { |
2381 | if (num == -EAGAIN) | |
2382 | break; | |
2383 | retval = num; | |
2384 | goto break_out; | |
2385 | } | |
2386 | b += num; | |
2387 | nr -= num; | |
2388 | if (nr == 0) | |
2389 | break; | |
d414034e | 2390 | if (process_output(*b, tty) < 0) |
1da177e4 LT |
2391 | break; |
2392 | b++; nr--; | |
2393 | } | |
f34d7a5b AC |
2394 | if (tty->ops->flush_chars) |
2395 | tty->ops->flush_chars(tty); | |
1da177e4 | 2396 | } else { |
4291086b PH |
2397 | struct n_tty_data *ldata = tty->disc_data; |
2398 | ||
d6afe27b | 2399 | while (nr > 0) { |
4291086b | 2400 | mutex_lock(&ldata->output_lock); |
68d90d5f | 2401 | num = tty->ops->write(tty, b, nr); |
4291086b | 2402 | mutex_unlock(&ldata->output_lock); |
68d90d5f JSS |
2403 | if (num < 0) { |
2404 | retval = num; | |
d6afe27b RZ |
2405 | goto break_out; |
2406 | } | |
68d90d5f | 2407 | if (!num) |
d6afe27b | 2408 | break; |
68d90d5f JSS |
2409 | b += num; |
2410 | nr -= num; | |
1da177e4 | 2411 | } |
1da177e4 LT |
2412 | } |
2413 | if (!nr) | |
2414 | break; | |
c96cf923 | 2415 | if (tty_io_nonblock(tty, file)) { |
1da177e4 LT |
2416 | retval = -EAGAIN; |
2417 | break; | |
2418 | } | |
9356b535 PH |
2419 | up_read(&tty->termios_rwsem); |
2420 | ||
97d9e28d | 2421 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
9356b535 PH |
2422 | |
2423 | down_read(&tty->termios_rwsem); | |
1da177e4 LT |
2424 | } |
2425 | break_out: | |
1da177e4 | 2426 | remove_wait_queue(&tty->write_wait, &wait); |
87108bc9 | 2427 | if (nr && tty->fasync) |
ff8cb0fd | 2428 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
9356b535 | 2429 | up_read(&tty->termios_rwsem); |
1da177e4 LT |
2430 | return (b - buf) ? b - buf : retval; |
2431 | } | |
2432 | ||
2433 | /** | |
98629663 JS |
2434 | * n_tty_poll - poll method for N_TTY |
2435 | * @tty: terminal device | |
2436 | * @file: file accessing it | |
2437 | * @wait: poll table | |
1da177e4 | 2438 | * |
98629663 JS |
2439 | * Called when the line discipline is asked to poll() for data or for special |
2440 | * events. This code is not serialized with respect to other events save | |
2441 | * open/close. | |
1da177e4 | 2442 | * |
98629663 JS |
2443 | * This code must be sure never to sleep through a hangup. |
2444 | * | |
2445 | * Locking: called without the kernel lock held -- fine. | |
1da177e4 | 2446 | */ |
afc9a42b | 2447 | static __poll_t n_tty_poll(struct tty_struct *tty, struct file *file, |
4edf1827 | 2448 | poll_table *wait) |
1da177e4 | 2449 | { |
afc9a42b | 2450 | __poll_t mask = 0; |
1da177e4 LT |
2451 | |
2452 | poll_wait(file, &tty->read_wait, wait); | |
2453 | poll_wait(file, &tty->write_wait, wait); | |
eafbe67f | 2454 | if (input_available_p(tty, 1)) |
a9a08845 | 2455 | mask |= EPOLLIN | EPOLLRDNORM; |
0f40fbbc BB |
2456 | else { |
2457 | tty_buffer_flush_work(tty->port); | |
2458 | if (input_available_p(tty, 1)) | |
a9a08845 | 2459 | mask |= EPOLLIN | EPOLLRDNORM; |
0f40fbbc | 2460 | } |
64d608db | 2461 | if (tty->ctrl.packet && tty->link->ctrl.pktstatus) |
a9a08845 | 2462 | mask |= EPOLLPRI | EPOLLIN | EPOLLRDNORM; |
0f40fbbc | 2463 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) |
a9a08845 | 2464 | mask |= EPOLLHUP; |
1da177e4 | 2465 | if (tty_hung_up_p(file)) |
a9a08845 | 2466 | mask |= EPOLLHUP; |
f34d7a5b AC |
2467 | if (tty->ops->write && !tty_is_writelocked(tty) && |
2468 | tty_chars_in_buffer(tty) < WAKEUP_CHARS && | |
2469 | tty_write_room(tty) > 0) | |
a9a08845 | 2470 | mask |= EPOLLOUT | EPOLLWRNORM; |
1da177e4 LT |
2471 | return mask; |
2472 | } | |
2473 | ||
57c94121 | 2474 | static unsigned long inq_canon(struct n_tty_data *ldata) |
47afa7a5 | 2475 | { |
bc5a5e3f | 2476 | size_t nr, head, tail; |
47afa7a5 | 2477 | |
a73d3d69 | 2478 | if (ldata->canon_head == ldata->read_tail) |
47afa7a5 | 2479 | return 0; |
ba2e68ac JS |
2480 | head = ldata->canon_head; |
2481 | tail = ldata->read_tail; | |
bc5a5e3f | 2482 | nr = head - tail; |
47afa7a5 | 2483 | /* Skip EOF-chars.. */ |
3d63b7e4 | 2484 | while (MASK(head) != MASK(tail)) { |
819287f0 | 2485 | if (test_bit(MASK(tail), ldata->read_flags) && |
bc5a5e3f | 2486 | read_buf(ldata, tail) == __DISABLED_CHAR) |
47afa7a5 | 2487 | nr--; |
bc5a5e3f | 2488 | tail++; |
47afa7a5 AC |
2489 | } |
2490 | return nr; | |
2491 | } | |
2492 | ||
d78328bc JS |
2493 | static int n_tty_ioctl(struct tty_struct *tty, unsigned int cmd, |
2494 | unsigned long arg) | |
47afa7a5 | 2495 | { |
ba2e68ac | 2496 | struct n_tty_data *ldata = tty->disc_data; |
1e619477 | 2497 | unsigned int num; |
47afa7a5 AC |
2498 | |
2499 | switch (cmd) { | |
2500 | case TIOCOUTQ: | |
2501 | return put_user(tty_chars_in_buffer(tty), (int __user *) arg); | |
2502 | case TIOCINQ: | |
6d76bd26 | 2503 | down_write(&tty->termios_rwsem); |
966031f3 | 2504 | if (L_ICANON(tty) && !L_EXTPROC(tty)) |
1e619477 | 2505 | num = inq_canon(ldata); |
6d76bd26 | 2506 | else |
1e619477 | 2507 | num = read_cnt(ldata); |
6d76bd26 | 2508 | up_write(&tty->termios_rwsem); |
1e619477 | 2509 | return put_user(num, (unsigned int __user *) arg); |
47afa7a5 | 2510 | default: |
7c783601 | 2511 | return n_tty_ioctl_helper(tty, cmd, arg); |
47afa7a5 AC |
2512 | } |
2513 | } | |
2514 | ||
27228732 | 2515 | static struct tty_ldisc_ops n_tty_ops = { |
5e30d3bf | 2516 | .owner = THIS_MODULE, |
fbadf70a | 2517 | .num = N_TTY, |
e10cc1df PF |
2518 | .name = "n_tty", |
2519 | .open = n_tty_open, | |
2520 | .close = n_tty_close, | |
2521 | .flush_buffer = n_tty_flush_buffer, | |
11a96d18 AC |
2522 | .read = n_tty_read, |
2523 | .write = n_tty_write, | |
e10cc1df PF |
2524 | .ioctl = n_tty_ioctl, |
2525 | .set_termios = n_tty_set_termios, | |
11a96d18 | 2526 | .poll = n_tty_poll, |
e10cc1df | 2527 | .receive_buf = n_tty_receive_buf, |
f6c8dbe6 | 2528 | .write_wakeup = n_tty_write_wakeup, |
24a89d1c | 2529 | .receive_buf2 = n_tty_receive_buf2, |
6bb6fa69 | 2530 | .lookahead_buf = n_tty_lookahead_flow_ctrl, |
1da177e4 | 2531 | }; |
572b9adb RG |
2532 | |
2533 | /** | |
2534 | * n_tty_inherit_ops - inherit N_TTY methods | |
2535 | * @ops: struct tty_ldisc_ops where to save N_TTY methods | |
2536 | * | |
27228732 | 2537 | * Enables a 'subclass' line discipline to 'inherit' N_TTY methods. |
572b9adb RG |
2538 | */ |
2539 | ||
2540 | void n_tty_inherit_ops(struct tty_ldisc_ops *ops) | |
2541 | { | |
27228732 | 2542 | *ops = n_tty_ops; |
572b9adb | 2543 | ops->owner = NULL; |
572b9adb RG |
2544 | } |
2545 | EXPORT_SYMBOL_GPL(n_tty_inherit_ops); | |
27228732 PH |
2546 | |
2547 | void __init n_tty_init(void) | |
2548 | { | |
fbadf70a | 2549 | tty_register_ldisc(&n_tty_ops); |
27228732 | 2550 | } |