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1da177e4 1/*
1da177e4
LT
2 * Copyright (C) 1991, 1992 Linus Torvalds
3 *
4 * Added support for a Unix98-style ptmx device.
5 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
1da177e4 6 *
1da177e4
LT
7 */
8
fe9cd962 9#include <linux/module.h>
1da177e4 10#include <linux/errno.h>
1da177e4
LT
11#include <linux/interrupt.h>
12#include <linux/tty.h>
13#include <linux/tty_flip.h>
14#include <linux/fcntl.h>
3f07c014 15#include <linux/sched/signal.h>
1da177e4
LT
16#include <linux/string.h>
17#include <linux/major.h>
18#include <linux/mm.h>
19#include <linux/init.h>
d81ed103 20#include <linux/device.h>
fe9cd962 21#include <linux/uaccess.h>
1da177e4
LT
22#include <linux/bitops.h>
23#include <linux/devpts_fs.h>
5a0e3ad6 24#include <linux/slab.h>
d739e65b 25#include <linux/mutex.h>
01adc807 26#include <linux/poll.h>
1da177e4 27
d6847793
PH
28#undef TTY_DEBUG_HANGUP
29#ifdef TTY_DEBUG_HANGUP
30# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
31#else
32# define tty_debug_hangup(tty, f, args...) do {} while (0)
33#endif
fe9cd962 34
1da177e4 35#ifdef CONFIG_UNIX98_PTYS
da2bdf9a 36static struct tty_driver *ptm_driver;
1da177e4 37static struct tty_driver *pts_driver;
d739e65b 38static DEFINE_MUTEX(devpts_mutex);
1da177e4
LT
39#endif
40
fe9cd962 41static void pty_close(struct tty_struct *tty, struct file *filp)
1da177e4 42{
fe9cd962
AC
43 BUG_ON(!tty);
44 if (tty->driver->subtype == PTY_TYPE_MASTER)
45 WARN_ON(tty->count > 1);
46 else {
18900ca6 47 if (tty_io_error(tty))
69939035 48 return;
1da177e4
LT
49 if (tty->count > 2)
50 return;
51 }
69939035 52 set_bit(TTY_IO_ERROR, &tty->flags);
1da177e4
LT
53 wake_up_interruptible(&tty->read_wait);
54 wake_up_interruptible(&tty->write_wait);
4ed60fc2 55 spin_lock_irq(&tty->ctrl_lock);
1da177e4 56 tty->packet = 0;
4ed60fc2 57 spin_unlock_irq(&tty->ctrl_lock);
89c8d91e 58 /* Review - krefs on tty_link ?? */
1da177e4
LT
59 if (!tty->link)
60 return;
1da177e4 61 set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
0f40fbbc 62 wake_up_interruptible(&tty->link->read_wait);
1da177e4
LT
63 wake_up_interruptible(&tty->link->write_wait);
64 if (tty->driver->subtype == PTY_TYPE_MASTER) {
65 set_bit(TTY_OTHER_CLOSED, &tty->flags);
ce1000dd 66#ifdef CONFIG_UNIX98_PTYS
d739e65b 67 if (tty->driver == ptm_driver) {
b9f8033f 68 mutex_lock(&devpts_mutex);
7acf6cd8
PH
69 if (tty->link->driver_data)
70 devpts_pty_kill(tty->link->driver_data);
b9f8033f 71 mutex_unlock(&devpts_mutex);
d739e65b 72 }
ce1000dd 73#endif
11dbf203 74 tty_vhangup(tty->link);
1da177e4
LT
75 }
76}
77
78/*
79 * The unthrottle routine is called by the line discipline to signal
80 * that it can receive more characters. For PTY's, the TTY_THROTTLED
81 * flag is always set, to force the line discipline to always call the
fe9cd962 82 * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
1da177e4
LT
83 * characters in the queue. This is necessary since each time this
84 * happens, we need to wake up any sleeping processes that could be
85 * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
86 * for the pty buffer to be drained.
87 */
fe9cd962 88static void pty_unthrottle(struct tty_struct *tty)
1da177e4 89{
d945cb9c 90 tty_wakeup(tty->link);
1da177e4
LT
91 set_bit(TTY_THROTTLED, &tty->flags);
92}
93
d945cb9c
AC
94/**
95 * pty_write - write to a pty
96 * @tty: the tty we write from
97 * @buf: kernel buffer of data
98 * @count: bytes to write
762faaed 99 *
d945cb9c
AC
100 * Our "hardware" write method. Data is coming from the ldisc which
101 * may be in a non sleeping state. We simply throw this at the other
102 * end of the link as if we were an IRQ handler receiving stuff for
103 * the other side of the pty/tty pair.
1da177e4 104 */
d945cb9c 105
ac89a917 106static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
1da177e4
LT
107{
108 struct tty_struct *to = tty->link;
1da177e4 109
d945cb9c 110 if (tty->stopped)
1da177e4 111 return 0;
d945cb9c 112
d945cb9c
AC
113 if (c > 0) {
114 /* Stuff the data into the input queue of the other end */
05c7cd39 115 c = tty_insert_flip_string(to->port, buf, c);
d945cb9c 116 /* And shovel */
5ede5253 117 if (c)
2e124b4a 118 tty_flip_buffer_push(to->port);
762faaed 119 }
1da177e4
LT
120 return c;
121}
122
d945cb9c
AC
123/**
124 * pty_write_room - write space
125 * @tty: tty we are writing from
126 *
127 * Report how many bytes the ldisc can send into the queue for
128 * the other device.
129 */
130
1da177e4
LT
131static int pty_write_room(struct tty_struct *tty)
132{
85dfd81d
LT
133 if (tty->stopped)
134 return 0;
c81622ac 135 return tty_buffer_space_avail(tty->link->port);
1da177e4
LT
136}
137
d945cb9c
AC
138/**
139 * pty_chars_in_buffer - characters currently in our tx queue
140 * @tty: our tty
fe9cd962 141 *
d945cb9c
AC
142 * Report how much we have in the transmit queue. As everything is
143 * instantly at the other end this is easy to implement.
1da177e4 144 */
d945cb9c 145
1da177e4
LT
146static int pty_chars_in_buffer(struct tty_struct *tty)
147{
d945cb9c 148 return 0;
1da177e4
LT
149}
150
151/* Set the lock flag on a pty */
fe9cd962 152static int pty_set_lock(struct tty_struct *tty, int __user *arg)
1da177e4
LT
153{
154 int val;
fe9cd962 155 if (get_user(val, arg))
1da177e4
LT
156 return -EFAULT;
157 if (val)
158 set_bit(TTY_PTY_LOCK, &tty->flags);
159 else
160 clear_bit(TTY_PTY_LOCK, &tty->flags);
161 return 0;
162}
163
84fd7bdf
CG
164static int pty_get_lock(struct tty_struct *tty, int __user *arg)
165{
166 int locked = test_bit(TTY_PTY_LOCK, &tty->flags);
167 return put_user(locked, arg);
168}
169
06026d91
CG
170/* Set the packet mode on a pty */
171static int pty_set_pktmode(struct tty_struct *tty, int __user *arg)
172{
06026d91
CG
173 int pktmode;
174
175 if (get_user(pktmode, arg))
176 return -EFAULT;
177
6054c16e 178 spin_lock_irq(&tty->ctrl_lock);
06026d91
CG
179 if (pktmode) {
180 if (!tty->packet) {
06026d91 181 tty->link->ctrl_status = 0;
2622d73e
PH
182 smp_mb();
183 tty->packet = 1;
06026d91
CG
184 }
185 } else
186 tty->packet = 0;
6054c16e 187 spin_unlock_irq(&tty->ctrl_lock);
06026d91
CG
188
189 return 0;
190}
191
84fd7bdf
CG
192/* Get the packet mode of a pty */
193static int pty_get_pktmode(struct tty_struct *tty, int __user *arg)
194{
195 int pktmode = tty->packet;
196 return put_user(pktmode, arg);
197}
198
26df6d13 199/* Send a signal to the slave */
200static int pty_signal(struct tty_struct *tty, int sig)
201{
26df6d13 202 struct pid *pgrp;
203
37480a05
PH
204 if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP)
205 return -EINVAL;
206
26df6d13 207 if (tty->link) {
5b239542
PH
208 pgrp = tty_get_pgrp(tty->link);
209 if (pgrp)
210 kill_pgrp(pgrp, sig, 1);
26df6d13 211 put_pid(pgrp);
212 }
213 return 0;
214}
215
1da177e4
LT
216static void pty_flush_buffer(struct tty_struct *tty)
217{
218 struct tty_struct *to = tty->link;
1d1d14da 219 struct tty_ldisc *ld;
fe9cd962 220
1da177e4
LT
221 if (!to)
222 return;
1d1d14da
PH
223
224 ld = tty_ldisc_ref(to);
225 tty_buffer_flush(to, ld);
226 if (ld)
227 tty_ldisc_deref(ld);
228
1da177e4 229 if (to->packet) {
6054c16e 230 spin_lock_irq(&tty->ctrl_lock);
1da177e4
LT
231 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
232 wake_up_interruptible(&to->read_wait);
6054c16e 233 spin_unlock_irq(&tty->ctrl_lock);
1da177e4
LT
234 }
235}
236
fe9cd962 237static int pty_open(struct tty_struct *tty, struct file *filp)
1da177e4 238{
1da177e4 239 if (!tty || !tty->link)
7c61c3d8 240 return -ENODEV;
69939035 241
1da177e4
LT
242 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
243 goto out;
244 if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
245 goto out;
80cace72 246 if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1)
1da177e4
LT
247 goto out;
248
69939035 249 clear_bit(TTY_IO_ERROR, &tty->flags);
1da177e4
LT
250 clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
251 set_bit(TTY_THROTTLED, &tty->flags);
7c61c3d8
PH
252 return 0;
253
1da177e4 254out:
7c61c3d8
PH
255 set_bit(TTY_IO_ERROR, &tty->flags);
256 return -EIO;
1da177e4
LT
257}
258
fe9cd962
AC
259static void pty_set_termios(struct tty_struct *tty,
260 struct ktermios *old_termios)
1da177e4 261{
dbfcd851
PH
262 /* See if packet mode change of state. */
263 if (tty->link && tty->link->packet) {
9db276f8 264 int extproc = (old_termios->c_lflag & EXTPROC) | L_EXTPROC(tty);
dbfcd851
PH
265 int old_flow = ((old_termios->c_iflag & IXON) &&
266 (old_termios->c_cc[VSTOP] == '\023') &&
267 (old_termios->c_cc[VSTART] == '\021'));
268 int new_flow = (I_IXON(tty) &&
269 STOP_CHAR(tty) == '\023' &&
270 START_CHAR(tty) == '\021');
271 if ((old_flow != new_flow) || extproc) {
4d8c1dff 272 spin_lock_irq(&tty->ctrl_lock);
dbfcd851
PH
273 if (old_flow != new_flow) {
274 tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP);
275 if (new_flow)
276 tty->ctrl_status |= TIOCPKT_DOSTOP;
277 else
278 tty->ctrl_status |= TIOCPKT_NOSTOP;
279 }
280 if (extproc)
281 tty->ctrl_status |= TIOCPKT_IOCTL;
4d8c1dff 282 spin_unlock_irq(&tty->ctrl_lock);
dbfcd851
PH
283 wake_up_interruptible(&tty->link->read_wait);
284 }
285 }
286
adc8d746
AC
287 tty->termios.c_cflag &= ~(CSIZE | PARENB);
288 tty->termios.c_cflag |= (CS8 | CREAD);
1da177e4
LT
289}
290
fc6f6238
AC
291/**
292 * pty_do_resize - resize event
293 * @tty: tty being resized
c774bda2 294 * @ws: window size being set.
fc6f6238 295 *
3ad2f3fb 296 * Update the termios variables and send the necessary signals to
fc6f6238
AC
297 * peform a terminal resize correctly
298 */
299
159a8e92 300static int pty_resize(struct tty_struct *tty, struct winsize *ws)
fc6f6238
AC
301{
302 struct pid *pgrp, *rpgrp;
fc6f6238
AC
303 struct tty_struct *pty = tty->link;
304
305 /* For a PTY we need to lock the tty side */
dee4a0be 306 mutex_lock(&tty->winsize_mutex);
fc6f6238
AC
307 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
308 goto done;
309
5b239542
PH
310 /* Signal the foreground process group of both ptys */
311 pgrp = tty_get_pgrp(tty);
312 rpgrp = tty_get_pgrp(pty);
fc6f6238
AC
313
314 if (pgrp)
315 kill_pgrp(pgrp, SIGWINCH, 1);
316 if (rpgrp != pgrp && rpgrp)
317 kill_pgrp(rpgrp, SIGWINCH, 1);
318
319 put_pid(pgrp);
320 put_pid(rpgrp);
321
322 tty->winsize = *ws;
323 pty->winsize = *ws; /* Never used so will go away soon */
324done:
dee4a0be 325 mutex_unlock(&tty->winsize_mutex);
fc6f6238
AC
326 return 0;
327}
328
01adc807
PH
329/**
330 * pty_start - start() handler
331 * pty_stop - stop() handler
332 * @tty: tty being flow-controlled
333 *
334 * Propagates the TIOCPKT status to the master pty.
335 *
336 * NB: only the master pty can be in packet mode so only the slave
337 * needs start()/stop() handlers
338 */
339static void pty_start(struct tty_struct *tty)
340{
341 unsigned long flags;
342
01adc807 343 if (tty->link && tty->link->packet) {
54e8e5fc 344 spin_lock_irqsave(&tty->ctrl_lock, flags);
01adc807
PH
345 tty->ctrl_status &= ~TIOCPKT_STOP;
346 tty->ctrl_status |= TIOCPKT_START;
54e8e5fc 347 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
01adc807
PH
348 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
349 }
01adc807
PH
350}
351
352static void pty_stop(struct tty_struct *tty)
353{
354 unsigned long flags;
355
01adc807 356 if (tty->link && tty->link->packet) {
54e8e5fc 357 spin_lock_irqsave(&tty->ctrl_lock, flags);
01adc807
PH
358 tty->ctrl_status &= ~TIOCPKT_START;
359 tty->ctrl_status |= TIOCPKT_STOP;
54e8e5fc 360 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
01adc807
PH
361 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
362 }
01adc807
PH
363}
364
d155255a
AC
365/**
366 * pty_common_install - set up the pty pair
367 * @driver: the pty driver
368 * @tty: the tty being instantiated
2c964a2f 369 * @legacy: true if this is BSD style
d155255a
AC
370 *
371 * Perform the initial set up for the tty/pty pair. Called from the
372 * tty layer when the port is first opened.
373 *
374 * Locking: the caller must hold the tty_mutex
375 */
5d249bc6
JS
376static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
377 bool legacy)
bf970ee4
AC
378{
379 struct tty_struct *o_tty;
d03702a2 380 struct tty_port *ports[2];
bf970ee4 381 int idx = tty->index;
5d249bc6 382 int retval = -ENOMEM;
bf970ee4 383
55199ea3
PH
384 /* Opening the slave first has always returned -EIO */
385 if (driver->subtype != PTY_TYPE_MASTER)
386 return -EIO;
387
d03702a2
JS
388 ports[0] = kmalloc(sizeof **ports, GFP_KERNEL);
389 ports[1] = kmalloc(sizeof **ports, GFP_KERNEL);
6f9ea7ad 390 if (!ports[0] || !ports[1])
2c964a2f 391 goto err;
bf970ee4
AC
392 if (!try_module_get(driver->other->owner)) {
393 /* This cannot in fact currently happen */
2c964a2f 394 goto err;
bf970ee4 395 }
2c964a2f
RV
396 o_tty = alloc_tty_struct(driver->other, idx);
397 if (!o_tty)
398 goto err_put_module;
bf970ee4 399
2febdb63 400 tty_set_lock_subclass(o_tty);
d2b6f447 401 lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE);
2febdb63 402
5d249bc6
JS
403 if (legacy) {
404 /* We always use new tty termios data so we can do this
405 the easy way .. */
a3123fd0
PH
406 tty_init_termios(tty);
407 tty_init_termios(o_tty);
5d249bc6
JS
408
409 driver->other->ttys[idx] = o_tty;
410 driver->ttys[idx] = tty;
411 } else {
adc8d746
AC
412 memset(&tty->termios_locked, 0, sizeof(tty->termios_locked));
413 tty->termios = driver->init_termios;
414 memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked));
415 o_tty->termios = driver->other->init_termios;
5d249bc6 416 }
fe9cd962 417
bf970ee4
AC
418 /*
419 * Everything allocated ... set up the o_tty structure.
420 */
bf970ee4 421 tty_driver_kref_get(driver->other);
bf970ee4
AC
422 /* Establish the links in both directions */
423 tty->link = o_tty;
424 o_tty->link = tty;
d03702a2
JS
425 tty_port_init(ports[0]);
426 tty_port_init(ports[1]);
c81622ac
PH
427 tty_buffer_set_limit(ports[0], 8192);
428 tty_buffer_set_limit(ports[1], 8192);
d03702a2
JS
429 o_tty->port = ports[0];
430 tty->port = ports[1];
967fab69 431 o_tty->port->itty = o_tty;
bf970ee4 432
1d1d14da
PH
433 tty_buffer_set_lock_subclass(o_tty->port);
434
bf970ee4
AC
435 tty_driver_kref_get(driver);
436 tty->count++;
55199ea3 437 o_tty->count++;
bf970ee4 438 return 0;
a3123fd0 439
2c964a2f 440err_put_module:
07584d4a 441 module_put(driver->other->owner);
2c964a2f 442err:
d03702a2
JS
443 kfree(ports[0]);
444 kfree(ports[1]);
8a1b8d70 445 return retval;
bf970ee4
AC
446}
447
d03702a2
JS
448static void pty_cleanup(struct tty_struct *tty)
449{
81c79838 450 tty_port_put(tty->port);
d03702a2
JS
451}
452
5d249bc6
JS
453/* Traditional BSD devices */
454#ifdef CONFIG_LEGACY_PTYS
455
456static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
457{
458 return pty_common_install(driver, tty, true);
459}
460
d155255a
AC
461static void pty_remove(struct tty_driver *driver, struct tty_struct *tty)
462{
463 struct tty_struct *pair = tty->link;
464 driver->ttys[tty->index] = NULL;
465 if (pair)
466 pair->driver->ttys[pair->index] = NULL;
467}
468
6caa76b7 469static int pty_bsd_ioctl(struct tty_struct *tty,
1da177e4
LT
470 unsigned int cmd, unsigned long arg)
471{
472 switch (cmd) {
473 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
474 return pty_set_lock(tty, (int __user *) arg);
84fd7bdf
CG
475 case TIOCGPTLCK: /* Get PT Lock status */
476 return pty_get_lock(tty, (int __user *)arg);
06026d91
CG
477 case TIOCPKT: /* Set PT packet mode */
478 return pty_set_pktmode(tty, (int __user *)arg);
84fd7bdf
CG
479 case TIOCGPKT: /* Get PT packet mode */
480 return pty_get_pktmode(tty, (int __user *)arg);
26df6d13 481 case TIOCSIG: /* Send signal to other side of pty */
482 return pty_signal(tty, (int) arg);
ded2f295
JS
483 case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */
484 return -EINVAL;
1da177e4
LT
485 }
486 return -ENOIOCTLCMD;
487}
488
dc8c8587 489static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
7154988f
PG
490/*
491 * not really modular, but the easiest way to keep compat with existing
492 * bootargs behaviour is to continue using module_param here.
493 */
dc8c8587
KS
494module_param(legacy_count, int, 0);
495
342a5971
LT
496/*
497 * The master side of a pty can do TIOCSPTLCK and thus
498 * has pty_bsd_ioctl.
499 */
500static const struct tty_operations master_pty_ops_bsd = {
501 .install = pty_install,
3e8e88ca
AC
502 .open = pty_open,
503 .close = pty_close,
504 .write = pty_write,
505 .write_room = pty_write_room,
506 .flush_buffer = pty_flush_buffer,
507 .chars_in_buffer = pty_chars_in_buffer,
508 .unthrottle = pty_unthrottle,
3e8e88ca 509 .ioctl = pty_bsd_ioctl,
d03702a2 510 .cleanup = pty_cleanup,
d155255a
AC
511 .resize = pty_resize,
512 .remove = pty_remove
3e8e88ca
AC
513};
514
342a5971
LT
515static const struct tty_operations slave_pty_ops_bsd = {
516 .install = pty_install,
517 .open = pty_open,
518 .close = pty_close,
519 .write = pty_write,
520 .write_room = pty_write_room,
521 .flush_buffer = pty_flush_buffer,
522 .chars_in_buffer = pty_chars_in_buffer,
523 .unthrottle = pty_unthrottle,
524 .set_termios = pty_set_termios,
d03702a2 525 .cleanup = pty_cleanup,
d155255a 526 .resize = pty_resize,
01adc807
PH
527 .start = pty_start,
528 .stop = pty_stop,
d155255a 529 .remove = pty_remove
342a5971
LT
530};
531
1da177e4
LT
532static void __init legacy_pty_init(void)
533{
342a5971
LT
534 struct tty_driver *pty_driver, *pty_slave_driver;
535
dc8c8587
KS
536 if (legacy_count <= 0)
537 return;
1da177e4 538
21aca2fa
JS
539 pty_driver = tty_alloc_driver(legacy_count,
540 TTY_DRIVER_RESET_TERMIOS |
541 TTY_DRIVER_REAL_RAW |
542 TTY_DRIVER_DYNAMIC_ALLOC);
c3a6344a 543 if (IS_ERR(pty_driver))
1da177e4
LT
544 panic("Couldn't allocate pty driver");
545
21aca2fa
JS
546 pty_slave_driver = tty_alloc_driver(legacy_count,
547 TTY_DRIVER_RESET_TERMIOS |
548 TTY_DRIVER_REAL_RAW |
549 TTY_DRIVER_DYNAMIC_ALLOC);
c3a6344a 550 if (IS_ERR(pty_slave_driver))
1da177e4
LT
551 panic("Couldn't allocate pty slave driver");
552
1da177e4
LT
553 pty_driver->driver_name = "pty_master";
554 pty_driver->name = "pty";
1da177e4
LT
555 pty_driver->major = PTY_MASTER_MAJOR;
556 pty_driver->minor_start = 0;
557 pty_driver->type = TTY_DRIVER_TYPE_PTY;
558 pty_driver->subtype = PTY_TYPE_MASTER;
559 pty_driver->init_termios = tty_std_termios;
560 pty_driver->init_termios.c_iflag = 0;
561 pty_driver->init_termios.c_oflag = 0;
562 pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
563 pty_driver->init_termios.c_lflag = 0;
606d099c
AC
564 pty_driver->init_termios.c_ispeed = 38400;
565 pty_driver->init_termios.c_ospeed = 38400;
1da177e4 566 pty_driver->other = pty_slave_driver;
342a5971 567 tty_set_operations(pty_driver, &master_pty_ops_bsd);
1da177e4 568
1da177e4
LT
569 pty_slave_driver->driver_name = "pty_slave";
570 pty_slave_driver->name = "ttyp";
1da177e4
LT
571 pty_slave_driver->major = PTY_SLAVE_MAJOR;
572 pty_slave_driver->minor_start = 0;
573 pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
574 pty_slave_driver->subtype = PTY_TYPE_SLAVE;
575 pty_slave_driver->init_termios = tty_std_termios;
576 pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
606d099c
AC
577 pty_slave_driver->init_termios.c_ispeed = 38400;
578 pty_slave_driver->init_termios.c_ospeed = 38400;
1da177e4 579 pty_slave_driver->other = pty_driver;
342a5971 580 tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
1da177e4
LT
581
582 if (tty_register_driver(pty_driver))
583 panic("Couldn't register pty driver");
584 if (tty_register_driver(pty_slave_driver))
585 panic("Couldn't register pty slave driver");
586}
587#else
588static inline void legacy_pty_init(void) { }
589#endif
590
591/* Unix98 devices */
592#ifdef CONFIG_UNIX98_PTYS
1da177e4 593
d81ed103
AC
594static struct cdev ptmx_cdev;
595
6caa76b7 596static int pty_unix98_ioctl(struct tty_struct *tty,
1da177e4
LT
597 unsigned int cmd, unsigned long arg)
598{
599 switch (cmd) {
600 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
601 return pty_set_lock(tty, (int __user *)arg);
84fd7bdf
CG
602 case TIOCGPTLCK: /* Get PT Lock status */
603 return pty_get_lock(tty, (int __user *)arg);
06026d91
CG
604 case TIOCPKT: /* Set PT packet mode */
605 return pty_set_pktmode(tty, (int __user *)arg);
84fd7bdf
CG
606 case TIOCGPKT: /* Get PT packet mode */
607 return pty_get_pktmode(tty, (int __user *)arg);
1da177e4
LT
608 case TIOCGPTN: /* Get PT Number */
609 return put_user(tty->index, (unsigned int __user *)arg);
26df6d13 610 case TIOCSIG: /* Send signal to other side of pty */
611 return pty_signal(tty, (int) arg);
1da177e4
LT
612 }
613
614 return -ENOIOCTLCMD;
615}
616
99f1fe18
AC
617/**
618 * ptm_unix98_lookup - find a pty master
619 * @driver: ptm driver
620 * @idx: tty index
621 *
622 * Look up a pty master device. Called under the tty_mutex for now.
623 * This provides our locking.
624 */
625
15f1a633 626static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
8ead9dd5 627 struct file *file, int idx)
99f1fe18 628{
593a27c4
KK
629 /* Master must be open via /dev/ptmx */
630 return ERR_PTR(-EIO);
99f1fe18
AC
631}
632
633/**
634 * pts_unix98_lookup - find a pty slave
635 * @driver: pts driver
636 * @idx: tty index
637 *
638 * Look up a pty master device. Called under the tty_mutex for now.
d739e65b 639 * This provides our locking for the tty pointer.
99f1fe18
AC
640 */
641
15f1a633 642static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
8ead9dd5 643 struct file *file, int idx)
99f1fe18 644{
d739e65b
AC
645 struct tty_struct *tty;
646
647 mutex_lock(&devpts_mutex);
8ead9dd5 648 tty = devpts_get_priv(file->f_path.dentry);
d739e65b 649 mutex_unlock(&devpts_mutex);
99f1fe18
AC
650 /* Master must be open before slave */
651 if (!tty)
652 return ERR_PTR(-EIO);
653 return tty;
654}
655
bf970ee4 656static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
8b0a88d5 657{
5d249bc6 658 return pty_common_install(driver, tty, false);
8b0a88d5
AC
659}
660
f4b208eb 661/* this is called once with whichever end is closed last */
c1e33af1 662static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
f4b208eb 663{
67245ff3 664 struct pts_fs_info *fsi;
2831c89f
HK
665
666 if (tty->driver->subtype == PTY_TYPE_MASTER)
67245ff3 667 fsi = tty->driver_data;
2831c89f 668 else
67245ff3 669 fsi = tty->link->driver_data;
5353ed8d
CIK
670
671 if (fsi) {
672 devpts_kill_index(fsi, tty->index);
673 devpts_release(fsi);
674 }
f4b208eb
JS
675}
676
feebed65 677static const struct tty_operations ptm_unix98_ops = {
99f1fe18 678 .lookup = ptm_unix98_lookup,
bf970ee4 679 .install = pty_unix98_install,
7171604a 680 .remove = pty_unix98_remove,
3e8e88ca
AC
681 .open = pty_open,
682 .close = pty_close,
683 .write = pty_write,
684 .write_room = pty_write_room,
685 .flush_buffer = pty_flush_buffer,
686 .chars_in_buffer = pty_chars_in_buffer,
687 .unthrottle = pty_unthrottle,
feebed65 688 .ioctl = pty_unix98_ioctl,
36b3c070
AC
689 .resize = pty_resize,
690 .cleanup = pty_cleanup
3e8e88ca
AC
691};
692
99f1fe18
AC
693static const struct tty_operations pty_unix98_ops = {
694 .lookup = pts_unix98_lookup,
bf970ee4 695 .install = pty_unix98_install,
7171604a 696 .remove = pty_unix98_remove,
99f1fe18
AC
697 .open = pty_open,
698 .close = pty_close,
699 .write = pty_write,
700 .write_room = pty_write_room,
701 .flush_buffer = pty_flush_buffer,
702 .chars_in_buffer = pty_chars_in_buffer,
703 .unthrottle = pty_unthrottle,
704 .set_termios = pty_set_termios,
01adc807
PH
705 .start = pty_start,
706 .stop = pty_stop,
d03702a2 707 .cleanup = pty_cleanup,
99f1fe18 708};
d81ed103
AC
709
710/**
711 * ptmx_open - open a unix 98 pty master
712 * @inode: inode of device file
713 * @filp: file pointer to tty
714 *
715 * Allocate a unix98 pty master device from the ptmx driver.
716 *
717 * Locking: tty_mutex protects the init_dev work. tty->count should
b9f8033f 718 * protect the rest.
d81ed103
AC
719 * allocated_ptys_lock handles the list of free pty numbers
720 */
721
64ba3dc3 722static int ptmx_open(struct inode *inode, struct file *filp)
d81ed103 723{
67245ff3 724 struct pts_fs_info *fsi;
d81ed103 725 struct tty_struct *tty;
8ead9dd5 726 struct dentry *dentry;
d81ed103
AC
727 int retval;
728 int index;
729
730 nonseekable_open(inode, filp);
731
b0b88565
LT
732 /* We refuse fsnotify events on ptmx, since it's a shared resource */
733 filp->f_mode |= FMODE_NONOTIFY;
734
fa90e1c9
JS
735 retval = tty_alloc_file(filp);
736 if (retval)
737 return retval;
738
eedf265a
EB
739 fsi = devpts_acquire(filp);
740 if (IS_ERR(fsi)) {
741 retval = PTR_ERR(fsi);
67245ff3 742 goto out_free_file;
eedf265a 743 }
67245ff3 744
d81ed103 745 /* find a device that is not in use. */
89c8d91e 746 mutex_lock(&devpts_mutex);
67245ff3 747 index = devpts_new_index(fsi);
89c8d91e
AC
748 mutex_unlock(&devpts_mutex);
749
67245ff3
LT
750 retval = index;
751 if (index < 0)
eedf265a 752 goto out_put_fsi;
d81ed103 753
d81ed103 754
67245ff3
LT
755 mutex_lock(&tty_mutex);
756 tty = tty_init_dev(ptm_driver, index);
89c8d91e
AC
757 /* The tty returned here is locked so we can safely
758 drop the mutex */
759 mutex_unlock(&tty_mutex);
760
67245ff3
LT
761 retval = PTR_ERR(tty);
762 if (IS_ERR(tty))
763 goto out;
ee2ffa0d 764
2831c89f 765 /*
67245ff3
LT
766 * From here on out, the tty is "live", and the index and
767 * fsi will be killed/put by the tty_release()
2831c89f 768 */
67245ff3
LT
769 set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
770 tty->driver_data = fsi;
2831c89f 771
fa90e1c9 772 tty_add_file(tty, filp);
d81ed103 773
8ead9dd5
LT
774 dentry = devpts_pty_new(fsi, index, tty->link);
775 if (IS_ERR(dentry)) {
776 retval = PTR_ERR(dentry);
1177c0ef 777 goto err_release;
162b97cf 778 }
8ead9dd5 779 tty->link->driver_data = dentry;
d81ed103
AC
780
781 retval = ptm_driver->ops->open(tty, filp);
64ba3dc3 782 if (retval)
1177c0ef
JS
783 goto err_release;
784
d435cefe 785 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
d6847793 786
89c8d91e 787 tty_unlock(tty);
1177c0ef
JS
788 return 0;
789err_release:
89c8d91e 790 tty_unlock(tty);
67245ff3 791 // This will also put-ref the fsi
eeb89d91 792 tty_release(inode, filp);
d81ed103
AC
793 return retval;
794out:
67245ff3 795 devpts_kill_index(fsi, index);
eedf265a
EB
796out_put_fsi:
797 devpts_release(fsi);
67245ff3 798out_free_file:
fa90e1c9 799 tty_free_file(filp);
64ba3dc3 800 return retval;
d81ed103
AC
801}
802
d2ec3f77 803static struct file_operations ptmx_fops __ro_after_init;
d81ed103 804
1da177e4
LT
805static void __init unix98_pty_init(void)
806{
21aca2fa
JS
807 ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
808 TTY_DRIVER_RESET_TERMIOS |
809 TTY_DRIVER_REAL_RAW |
810 TTY_DRIVER_DYNAMIC_DEV |
811 TTY_DRIVER_DEVPTS_MEM |
812 TTY_DRIVER_DYNAMIC_ALLOC);
c3a6344a 813 if (IS_ERR(ptm_driver))
1da177e4 814 panic("Couldn't allocate Unix98 ptm driver");
21aca2fa
JS
815 pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
816 TTY_DRIVER_RESET_TERMIOS |
817 TTY_DRIVER_REAL_RAW |
818 TTY_DRIVER_DYNAMIC_DEV |
819 TTY_DRIVER_DEVPTS_MEM |
820 TTY_DRIVER_DYNAMIC_ALLOC);
c3a6344a 821 if (IS_ERR(pts_driver))
1da177e4
LT
822 panic("Couldn't allocate Unix98 pts driver");
823
1da177e4
LT
824 ptm_driver->driver_name = "pty_master";
825 ptm_driver->name = "ptm";
826 ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
827 ptm_driver->minor_start = 0;
828 ptm_driver->type = TTY_DRIVER_TYPE_PTY;
829 ptm_driver->subtype = PTY_TYPE_MASTER;
830 ptm_driver->init_termios = tty_std_termios;
831 ptm_driver->init_termios.c_iflag = 0;
832 ptm_driver->init_termios.c_oflag = 0;
833 ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
834 ptm_driver->init_termios.c_lflag = 0;
606d099c
AC
835 ptm_driver->init_termios.c_ispeed = 38400;
836 ptm_driver->init_termios.c_ospeed = 38400;
1da177e4 837 ptm_driver->other = pts_driver;
feebed65 838 tty_set_operations(ptm_driver, &ptm_unix98_ops);
1da177e4 839
1da177e4
LT
840 pts_driver->driver_name = "pty_slave";
841 pts_driver->name = "pts";
842 pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
843 pts_driver->minor_start = 0;
844 pts_driver->type = TTY_DRIVER_TYPE_PTY;
845 pts_driver->subtype = PTY_TYPE_SLAVE;
846 pts_driver->init_termios = tty_std_termios;
847 pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
606d099c
AC
848 pts_driver->init_termios.c_ispeed = 38400;
849 pts_driver->init_termios.c_ospeed = 38400;
1da177e4 850 pts_driver->other = ptm_driver;
99f1fe18 851 tty_set_operations(pts_driver, &pty_unix98_ops);
fe9cd962 852
1da177e4
LT
853 if (tty_register_driver(ptm_driver))
854 panic("Couldn't register Unix98 ptm driver");
855 if (tty_register_driver(pts_driver))
856 panic("Couldn't register Unix98 pts driver");
857
d81ed103
AC
858 /* Now create the /dev/ptmx special device */
859 tty_default_fops(&ptmx_fops);
860 ptmx_fops.open = ptmx_open;
861
862 cdev_init(&ptmx_cdev, &ptmx_fops);
863 if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
864 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
82f8c35f 865 panic("Couldn't register /dev/ptmx driver");
d81ed103 866 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
1da177e4 867}
d81ed103 868
1da177e4
LT
869#else
870static inline void unix98_pty_init(void) { }
871#endif
872
873static int __init pty_init(void)
874{
875 legacy_pty_init();
876 unix98_pty_init();
877 return 0;
878}
7154988f 879device_initcall(pty_init);