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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 *
5 * Added support for a Unix98-style ptmx device.
6 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
7 *
8 */
9
10#include <linux/module.h>
11#include <linux/errno.h>
12#include <linux/interrupt.h>
13#include <linux/tty.h>
14#include <linux/tty_flip.h>
15#include <linux/fcntl.h>
16#include <linux/sched/signal.h>
17#include <linux/string.h>
18#include <linux/major.h>
19#include <linux/mm.h>
20#include <linux/init.h>
21#include <linux/device.h>
22#include <linux/uaccess.h>
23#include <linux/bitops.h>
24#include <linux/devpts_fs.h>
25#include <linux/slab.h>
26#include <linux/mutex.h>
27#include <linux/poll.h>
28#include <linux/mount.h>
29#include <linux/file.h>
30#include <linux/ioctl.h>
31#include <linux/compat.h>
32#include "tty.h"
33
34#undef TTY_DEBUG_HANGUP
35#ifdef TTY_DEBUG_HANGUP
36# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
37#else
38# define tty_debug_hangup(tty, f, args...) do {} while (0)
39#endif
40
41#ifdef CONFIG_UNIX98_PTYS
42static struct tty_driver *ptm_driver;
43static struct tty_driver *pts_driver;
44static DEFINE_MUTEX(devpts_mutex);
45#endif
46
47static void pty_close(struct tty_struct *tty, struct file *filp)
48{
49 if (tty->driver->subtype == PTY_TYPE_MASTER)
50 WARN_ON(tty->count > 1);
51 else {
52 if (tty_io_error(tty))
53 return;
54 if (tty->count > 2)
55 return;
56 }
57 set_bit(TTY_IO_ERROR, &tty->flags);
58 wake_up_interruptible(&tty->read_wait);
59 wake_up_interruptible(&tty->write_wait);
60 spin_lock_irq(&tty->ctrl.lock);
61 tty->ctrl.packet = false;
62 spin_unlock_irq(&tty->ctrl.lock);
63 /* Review - krefs on tty_link ?? */
64 if (!tty->link)
65 return;
66 set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
67 wake_up_interruptible(&tty->link->read_wait);
68 wake_up_interruptible(&tty->link->write_wait);
69 if (tty->driver->subtype == PTY_TYPE_MASTER) {
70 set_bit(TTY_OTHER_CLOSED, &tty->flags);
71#ifdef CONFIG_UNIX98_PTYS
72 if (tty->driver == ptm_driver) {
73 mutex_lock(&devpts_mutex);
74 if (tty->link->driver_data)
75 devpts_pty_kill(tty->link->driver_data);
76 mutex_unlock(&devpts_mutex);
77 }
78#endif
79 tty_vhangup(tty->link);
80 }
81}
82
83/*
84 * The unthrottle routine is called by the line discipline to signal
85 * that it can receive more characters. For PTY's, the TTY_THROTTLED
86 * flag is always set, to force the line discipline to always call the
87 * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
88 * characters in the queue. This is necessary since each time this
89 * happens, we need to wake up any sleeping processes that could be
90 * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
91 * for the pty buffer to be drained.
92 */
93static void pty_unthrottle(struct tty_struct *tty)
94{
95 tty_wakeup(tty->link);
96 set_bit(TTY_THROTTLED, &tty->flags);
97}
98
99/**
100 * pty_write - write to a pty
101 * @tty: the tty we write from
102 * @buf: kernel buffer of data
103 * @c: bytes to write
104 *
105 * Our "hardware" write method. Data is coming from the ldisc which
106 * may be in a non sleeping state. We simply throw this at the other
107 * end of the link as if we were an IRQ handler receiving stuff for
108 * the other side of the pty/tty pair.
109 */
110
111static ssize_t pty_write(struct tty_struct *tty, const u8 *buf, size_t c)
112{
113 struct tty_struct *to = tty->link;
114
115 if (tty->flow.stopped || !c)
116 return 0;
117
118 return tty_insert_flip_string_and_push_buffer(to->port, buf, c);
119}
120
121/**
122 * pty_write_room - write space
123 * @tty: tty we are writing from
124 *
125 * Report how many bytes the ldisc can send into the queue for
126 * the other device.
127 */
128
129static unsigned int pty_write_room(struct tty_struct *tty)
130{
131 if (tty->flow.stopped)
132 return 0;
133 return tty_buffer_space_avail(tty->link->port);
134}
135
136/* Set the lock flag on a pty */
137static int pty_set_lock(struct tty_struct *tty, int __user *arg)
138{
139 int val;
140
141 if (get_user(val, arg))
142 return -EFAULT;
143 if (val)
144 set_bit(TTY_PTY_LOCK, &tty->flags);
145 else
146 clear_bit(TTY_PTY_LOCK, &tty->flags);
147 return 0;
148}
149
150static int pty_get_lock(struct tty_struct *tty, int __user *arg)
151{
152 int locked = test_bit(TTY_PTY_LOCK, &tty->flags);
153
154 return put_user(locked, arg);
155}
156
157/* Set the packet mode on a pty */
158static int pty_set_pktmode(struct tty_struct *tty, int __user *arg)
159{
160 int pktmode;
161
162 if (get_user(pktmode, arg))
163 return -EFAULT;
164
165 spin_lock_irq(&tty->ctrl.lock);
166 if (pktmode) {
167 if (!tty->ctrl.packet) {
168 tty->link->ctrl.pktstatus = 0;
169 smp_mb();
170 tty->ctrl.packet = true;
171 }
172 } else
173 tty->ctrl.packet = false;
174 spin_unlock_irq(&tty->ctrl.lock);
175
176 return 0;
177}
178
179/* Get the packet mode of a pty */
180static int pty_get_pktmode(struct tty_struct *tty, int __user *arg)
181{
182 int pktmode = tty->ctrl.packet;
183
184 return put_user(pktmode, arg);
185}
186
187/* Send a signal to the slave */
188static int pty_signal(struct tty_struct *tty, int sig)
189{
190 struct pid *pgrp;
191
192 if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP)
193 return -EINVAL;
194
195 if (tty->link) {
196 pgrp = tty_get_pgrp(tty->link);
197 if (pgrp)
198 kill_pgrp(pgrp, sig, 1);
199 put_pid(pgrp);
200 }
201 return 0;
202}
203
204static void pty_flush_buffer(struct tty_struct *tty)
205{
206 struct tty_struct *to = tty->link;
207
208 if (!to)
209 return;
210
211 tty_buffer_flush(to, NULL);
212 if (to->ctrl.packet) {
213 spin_lock_irq(&tty->ctrl.lock);
214 tty->ctrl.pktstatus |= TIOCPKT_FLUSHWRITE;
215 wake_up_interruptible(&to->read_wait);
216 spin_unlock_irq(&tty->ctrl.lock);
217 }
218}
219
220static int pty_open(struct tty_struct *tty, struct file *filp)
221{
222 if (!tty || !tty->link)
223 return -ENODEV;
224
225 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
226 goto out;
227 if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
228 goto out;
229 if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1)
230 goto out;
231
232 clear_bit(TTY_IO_ERROR, &tty->flags);
233 clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
234 set_bit(TTY_THROTTLED, &tty->flags);
235 return 0;
236
237out:
238 set_bit(TTY_IO_ERROR, &tty->flags);
239 return -EIO;
240}
241
242static void pty_set_termios(struct tty_struct *tty,
243 const struct ktermios *old_termios)
244{
245 /* See if packet mode change of state. */
246 if (tty->link && tty->link->ctrl.packet) {
247 int extproc = (old_termios->c_lflag & EXTPROC) | L_EXTPROC(tty);
248 int old_flow = ((old_termios->c_iflag & IXON) &&
249 (old_termios->c_cc[VSTOP] == '\023') &&
250 (old_termios->c_cc[VSTART] == '\021'));
251 int new_flow = (I_IXON(tty) &&
252 STOP_CHAR(tty) == '\023' &&
253 START_CHAR(tty) == '\021');
254 if ((old_flow != new_flow) || extproc) {
255 spin_lock_irq(&tty->ctrl.lock);
256 if (old_flow != new_flow) {
257 tty->ctrl.pktstatus &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP);
258 if (new_flow)
259 tty->ctrl.pktstatus |= TIOCPKT_DOSTOP;
260 else
261 tty->ctrl.pktstatus |= TIOCPKT_NOSTOP;
262 }
263 if (extproc)
264 tty->ctrl.pktstatus |= TIOCPKT_IOCTL;
265 spin_unlock_irq(&tty->ctrl.lock);
266 wake_up_interruptible(&tty->link->read_wait);
267 }
268 }
269
270 tty->termios.c_cflag &= ~(CSIZE | PARENB);
271 tty->termios.c_cflag |= (CS8 | CREAD);
272}
273
274/**
275 * pty_resize - resize event
276 * @tty: tty being resized
277 * @ws: window size being set.
278 *
279 * Update the termios variables and send the necessary signals to
280 * peform a terminal resize correctly
281 */
282
283static int pty_resize(struct tty_struct *tty, struct winsize *ws)
284{
285 struct pid *pgrp, *rpgrp;
286 struct tty_struct *pty = tty->link;
287
288 /* For a PTY we need to lock the tty side */
289 mutex_lock(&tty->winsize_mutex);
290 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
291 goto done;
292
293 /* Signal the foreground process group of both ptys */
294 pgrp = tty_get_pgrp(tty);
295 rpgrp = tty_get_pgrp(pty);
296
297 if (pgrp)
298 kill_pgrp(pgrp, SIGWINCH, 1);
299 if (rpgrp != pgrp && rpgrp)
300 kill_pgrp(rpgrp, SIGWINCH, 1);
301
302 put_pid(pgrp);
303 put_pid(rpgrp);
304
305 tty->winsize = *ws;
306 pty->winsize = *ws; /* Never used so will go away soon */
307done:
308 mutex_unlock(&tty->winsize_mutex);
309 return 0;
310}
311
312/**
313 * pty_start - start() handler
314 * pty_stop - stop() handler
315 * @tty: tty being flow-controlled
316 *
317 * Propagates the TIOCPKT status to the master pty.
318 *
319 * NB: only the master pty can be in packet mode so only the slave
320 * needs start()/stop() handlers
321 */
322static void pty_start(struct tty_struct *tty)
323{
324 unsigned long flags;
325
326 if (tty->link && tty->link->ctrl.packet) {
327 spin_lock_irqsave(&tty->ctrl.lock, flags);
328 tty->ctrl.pktstatus &= ~TIOCPKT_STOP;
329 tty->ctrl.pktstatus |= TIOCPKT_START;
330 spin_unlock_irqrestore(&tty->ctrl.lock, flags);
331 wake_up_interruptible_poll(&tty->link->read_wait, EPOLLIN);
332 }
333}
334
335static void pty_stop(struct tty_struct *tty)
336{
337 unsigned long flags;
338
339 if (tty->link && tty->link->ctrl.packet) {
340 spin_lock_irqsave(&tty->ctrl.lock, flags);
341 tty->ctrl.pktstatus &= ~TIOCPKT_START;
342 tty->ctrl.pktstatus |= TIOCPKT_STOP;
343 spin_unlock_irqrestore(&tty->ctrl.lock, flags);
344 wake_up_interruptible_poll(&tty->link->read_wait, EPOLLIN);
345 }
346}
347
348/**
349 * pty_common_install - set up the pty pair
350 * @driver: the pty driver
351 * @tty: the tty being instantiated
352 * @legacy: true if this is BSD style
353 *
354 * Perform the initial set up for the tty/pty pair. Called from the
355 * tty layer when the port is first opened.
356 *
357 * Locking: the caller must hold the tty_mutex
358 */
359static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
360 bool legacy)
361{
362 struct tty_struct *o_tty;
363 struct tty_port *ports[2];
364 int idx = tty->index;
365 int retval = -ENOMEM;
366
367 /* Opening the slave first has always returned -EIO */
368 if (driver->subtype != PTY_TYPE_MASTER)
369 return -EIO;
370
371 ports[0] = kmalloc(sizeof **ports, GFP_KERNEL);
372 ports[1] = kmalloc(sizeof **ports, GFP_KERNEL);
373 if (!ports[0] || !ports[1])
374 goto err;
375 if (!try_module_get(driver->other->owner)) {
376 /* This cannot in fact currently happen */
377 goto err;
378 }
379 o_tty = alloc_tty_struct(driver->other, idx);
380 if (!o_tty)
381 goto err_put_module;
382
383 tty_set_lock_subclass(o_tty);
384 lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE);
385
386 if (legacy) {
387 /* We always use new tty termios data so we can do this
388 the easy way .. */
389 tty_init_termios(tty);
390 tty_init_termios(o_tty);
391
392 driver->other->ttys[idx] = o_tty;
393 driver->ttys[idx] = tty;
394 } else {
395 memset(&tty->termios_locked, 0, sizeof(tty->termios_locked));
396 tty->termios = driver->init_termios;
397 memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked));
398 o_tty->termios = driver->other->init_termios;
399 }
400
401 /*
402 * Everything allocated ... set up the o_tty structure.
403 */
404 tty_driver_kref_get(driver->other);
405 /* Establish the links in both directions */
406 tty->link = o_tty;
407 o_tty->link = tty;
408 tty_port_init(ports[0]);
409 tty_port_init(ports[1]);
410 tty_buffer_set_limit(ports[0], 8192);
411 tty_buffer_set_limit(ports[1], 8192);
412 o_tty->port = ports[0];
413 tty->port = ports[1];
414 o_tty->port->itty = o_tty;
415
416 tty_buffer_set_lock_subclass(o_tty->port);
417
418 tty_driver_kref_get(driver);
419 tty->count++;
420 o_tty->count++;
421 return 0;
422
423err_put_module:
424 module_put(driver->other->owner);
425err:
426 kfree(ports[0]);
427 kfree(ports[1]);
428 return retval;
429}
430
431static void pty_cleanup(struct tty_struct *tty)
432{
433 tty_port_put(tty->port);
434}
435
436/* Traditional BSD devices */
437#ifdef CONFIG_LEGACY_PTYS
438
439static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
440{
441 return pty_common_install(driver, tty, true);
442}
443
444static void pty_remove(struct tty_driver *driver, struct tty_struct *tty)
445{
446 struct tty_struct *pair = tty->link;
447
448 driver->ttys[tty->index] = NULL;
449 if (pair)
450 pair->driver->ttys[pair->index] = NULL;
451}
452
453static int pty_bsd_ioctl(struct tty_struct *tty,
454 unsigned int cmd, unsigned long arg)
455{
456 switch (cmd) {
457 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
458 return pty_set_lock(tty, (int __user *) arg);
459 case TIOCGPTLCK: /* Get PT Lock status */
460 return pty_get_lock(tty, (int __user *)arg);
461 case TIOCPKT: /* Set PT packet mode */
462 return pty_set_pktmode(tty, (int __user *)arg);
463 case TIOCGPKT: /* Get PT packet mode */
464 return pty_get_pktmode(tty, (int __user *)arg);
465 case TIOCSIG: /* Send signal to other side of pty */
466 return pty_signal(tty, (int) arg);
467 case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */
468 return -EINVAL;
469 }
470 return -ENOIOCTLCMD;
471}
472
473#ifdef CONFIG_COMPAT
474static long pty_bsd_compat_ioctl(struct tty_struct *tty,
475 unsigned int cmd, unsigned long arg)
476{
477 /*
478 * PTY ioctls don't require any special translation between 32-bit and
479 * 64-bit userspace, they are already compatible.
480 */
481 return pty_bsd_ioctl(tty, cmd, (unsigned long)compat_ptr(arg));
482}
483#else
484#define pty_bsd_compat_ioctl NULL
485#endif
486
487static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
488/*
489 * not really modular, but the easiest way to keep compat with existing
490 * bootargs behaviour is to continue using module_param here.
491 */
492module_param(legacy_count, int, 0);
493
494/*
495 * The master side of a pty can do TIOCSPTLCK and thus
496 * has pty_bsd_ioctl.
497 */
498static const struct tty_operations master_pty_ops_bsd = {
499 .install = pty_install,
500 .open = pty_open,
501 .close = pty_close,
502 .write = pty_write,
503 .write_room = pty_write_room,
504 .flush_buffer = pty_flush_buffer,
505 .unthrottle = pty_unthrottle,
506 .ioctl = pty_bsd_ioctl,
507 .compat_ioctl = pty_bsd_compat_ioctl,
508 .cleanup = pty_cleanup,
509 .resize = pty_resize,
510 .remove = pty_remove
511};
512
513static const struct tty_operations slave_pty_ops_bsd = {
514 .install = pty_install,
515 .open = pty_open,
516 .close = pty_close,
517 .write = pty_write,
518 .write_room = pty_write_room,
519 .flush_buffer = pty_flush_buffer,
520 .unthrottle = pty_unthrottle,
521 .set_termios = pty_set_termios,
522 .cleanup = pty_cleanup,
523 .resize = pty_resize,
524 .start = pty_start,
525 .stop = pty_stop,
526 .remove = pty_remove
527};
528
529static void __init legacy_pty_init(void)
530{
531 struct tty_driver *pty_driver, *pty_slave_driver;
532
533 if (legacy_count <= 0)
534 return;
535
536 pty_driver = tty_alloc_driver(legacy_count,
537 TTY_DRIVER_RESET_TERMIOS |
538 TTY_DRIVER_REAL_RAW |
539 TTY_DRIVER_DYNAMIC_ALLOC);
540 if (IS_ERR(pty_driver))
541 panic("Couldn't allocate pty driver");
542
543 pty_slave_driver = tty_alloc_driver(legacy_count,
544 TTY_DRIVER_RESET_TERMIOS |
545 TTY_DRIVER_REAL_RAW |
546 TTY_DRIVER_DYNAMIC_ALLOC);
547 if (IS_ERR(pty_slave_driver))
548 panic("Couldn't allocate pty slave driver");
549
550 pty_driver->driver_name = "pty_master";
551 pty_driver->name = "pty";
552 pty_driver->major = PTY_MASTER_MAJOR;
553 pty_driver->minor_start = 0;
554 pty_driver->type = TTY_DRIVER_TYPE_PTY;
555 pty_driver->subtype = PTY_TYPE_MASTER;
556 pty_driver->init_termios = tty_std_termios;
557 pty_driver->init_termios.c_iflag = 0;
558 pty_driver->init_termios.c_oflag = 0;
559 pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
560 pty_driver->init_termios.c_lflag = 0;
561 pty_driver->init_termios.c_ispeed = 38400;
562 pty_driver->init_termios.c_ospeed = 38400;
563 pty_driver->other = pty_slave_driver;
564 tty_set_operations(pty_driver, &master_pty_ops_bsd);
565
566 pty_slave_driver->driver_name = "pty_slave";
567 pty_slave_driver->name = "ttyp";
568 pty_slave_driver->major = PTY_SLAVE_MAJOR;
569 pty_slave_driver->minor_start = 0;
570 pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
571 pty_slave_driver->subtype = PTY_TYPE_SLAVE;
572 pty_slave_driver->init_termios = tty_std_termios;
573 pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
574 pty_slave_driver->init_termios.c_ispeed = 38400;
575 pty_slave_driver->init_termios.c_ospeed = 38400;
576 pty_slave_driver->other = pty_driver;
577 tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
578
579 if (tty_register_driver(pty_driver))
580 panic("Couldn't register pty driver");
581 if (tty_register_driver(pty_slave_driver))
582 panic("Couldn't register pty slave driver");
583}
584#else
585static inline void legacy_pty_init(void) { }
586#endif
587
588/* Unix98 devices */
589#ifdef CONFIG_UNIX98_PTYS
590static struct cdev ptmx_cdev;
591
592/**
593 * ptm_open_peer - open the peer of a pty
594 * @master: the open struct file of the ptmx device node
595 * @tty: the master of the pty being opened
596 * @flags: the flags for open
597 *
598 * Provide a race free way for userspace to open the slave end of a pty
599 * (where they have the master fd and cannot access or trust the mount
600 * namespace /dev/pts was mounted inside).
601 */
602int ptm_open_peer(struct file *master, struct tty_struct *tty, int flags)
603{
604 int fd;
605 struct file *filp;
606 int retval = -EINVAL;
607 struct path path;
608
609 if (tty->driver != ptm_driver)
610 return -EIO;
611
612 fd = get_unused_fd_flags(flags);
613 if (fd < 0) {
614 retval = fd;
615 goto err;
616 }
617
618 /* Compute the slave's path */
619 path.mnt = devpts_mntget(master, tty->driver_data);
620 if (IS_ERR(path.mnt)) {
621 retval = PTR_ERR(path.mnt);
622 goto err_put;
623 }
624 path.dentry = tty->link->driver_data;
625
626 filp = dentry_open(&path, flags, current_cred());
627 mntput(path.mnt);
628 if (IS_ERR(filp)) {
629 retval = PTR_ERR(filp);
630 goto err_put;
631 }
632
633 fd_install(fd, filp);
634 return fd;
635
636err_put:
637 put_unused_fd(fd);
638err:
639 return retval;
640}
641
642static int pty_unix98_ioctl(struct tty_struct *tty,
643 unsigned int cmd, unsigned long arg)
644{
645 switch (cmd) {
646 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
647 return pty_set_lock(tty, (int __user *)arg);
648 case TIOCGPTLCK: /* Get PT Lock status */
649 return pty_get_lock(tty, (int __user *)arg);
650 case TIOCPKT: /* Set PT packet mode */
651 return pty_set_pktmode(tty, (int __user *)arg);
652 case TIOCGPKT: /* Get PT packet mode */
653 return pty_get_pktmode(tty, (int __user *)arg);
654 case TIOCGPTN: /* Get PT Number */
655 return put_user(tty->index, (unsigned int __user *)arg);
656 case TIOCSIG: /* Send signal to other side of pty */
657 return pty_signal(tty, (int) arg);
658 }
659
660 return -ENOIOCTLCMD;
661}
662
663#ifdef CONFIG_COMPAT
664static long pty_unix98_compat_ioctl(struct tty_struct *tty,
665 unsigned int cmd, unsigned long arg)
666{
667 /*
668 * PTY ioctls don't require any special translation between 32-bit and
669 * 64-bit userspace, they are already compatible.
670 */
671 return pty_unix98_ioctl(tty, cmd,
672 cmd == TIOCSIG ? arg : (unsigned long)compat_ptr(arg));
673}
674#else
675#define pty_unix98_compat_ioctl NULL
676#endif
677
678/**
679 * ptm_unix98_lookup - find a pty master
680 * @driver: ptm driver
681 * @file: unused
682 * @idx: tty index
683 *
684 * Look up a pty master device. Called under the tty_mutex for now.
685 * This provides our locking.
686 */
687
688static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
689 struct file *file, int idx)
690{
691 /* Master must be open via /dev/ptmx */
692 return ERR_PTR(-EIO);
693}
694
695/**
696 * pts_unix98_lookup - find a pty slave
697 * @driver: pts driver
698 * @file: file pointer to tty
699 * @idx: tty index
700 *
701 * Look up a pty master device. Called under the tty_mutex for now.
702 * This provides our locking for the tty pointer.
703 */
704
705static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
706 struct file *file, int idx)
707{
708 struct tty_struct *tty;
709
710 mutex_lock(&devpts_mutex);
711 tty = devpts_get_priv(file->f_path.dentry);
712 mutex_unlock(&devpts_mutex);
713 /* Master must be open before slave */
714 if (!tty)
715 return ERR_PTR(-EIO);
716 return tty;
717}
718
719static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
720{
721 return pty_common_install(driver, tty, false);
722}
723
724/* this is called once with whichever end is closed last */
725static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
726{
727 struct pts_fs_info *fsi;
728
729 if (tty->driver->subtype == PTY_TYPE_MASTER)
730 fsi = tty->driver_data;
731 else
732 fsi = tty->link->driver_data;
733
734 if (fsi) {
735 devpts_kill_index(fsi, tty->index);
736 devpts_release(fsi);
737 }
738}
739
740static void pty_show_fdinfo(struct tty_struct *tty, struct seq_file *m)
741{
742 seq_printf(m, "tty-index:\t%d\n", tty->index);
743}
744
745static const struct tty_operations ptm_unix98_ops = {
746 .lookup = ptm_unix98_lookup,
747 .install = pty_unix98_install,
748 .remove = pty_unix98_remove,
749 .open = pty_open,
750 .close = pty_close,
751 .write = pty_write,
752 .write_room = pty_write_room,
753 .flush_buffer = pty_flush_buffer,
754 .unthrottle = pty_unthrottle,
755 .ioctl = pty_unix98_ioctl,
756 .compat_ioctl = pty_unix98_compat_ioctl,
757 .resize = pty_resize,
758 .cleanup = pty_cleanup,
759 .show_fdinfo = pty_show_fdinfo,
760};
761
762static const struct tty_operations pty_unix98_ops = {
763 .lookup = pts_unix98_lookup,
764 .install = pty_unix98_install,
765 .remove = pty_unix98_remove,
766 .open = pty_open,
767 .close = pty_close,
768 .write = pty_write,
769 .write_room = pty_write_room,
770 .flush_buffer = pty_flush_buffer,
771 .unthrottle = pty_unthrottle,
772 .set_termios = pty_set_termios,
773 .start = pty_start,
774 .stop = pty_stop,
775 .cleanup = pty_cleanup,
776};
777
778/**
779 * ptmx_open - open a unix 98 pty master
780 * @inode: inode of device file
781 * @filp: file pointer to tty
782 *
783 * Allocate a unix98 pty master device from the ptmx driver.
784 *
785 * Locking: tty_mutex protects the init_dev work. tty->count should
786 * protect the rest.
787 * allocated_ptys_lock handles the list of free pty numbers
788 */
789
790static int ptmx_open(struct inode *inode, struct file *filp)
791{
792 struct pts_fs_info *fsi;
793 struct tty_struct *tty;
794 struct dentry *dentry;
795 int retval;
796 int index;
797
798 nonseekable_open(inode, filp);
799
800 /* We refuse fsnotify events on ptmx, since it's a shared resource */
801 filp->f_mode |= FMODE_NONOTIFY;
802
803 retval = tty_alloc_file(filp);
804 if (retval)
805 return retval;
806
807 fsi = devpts_acquire(filp);
808 if (IS_ERR(fsi)) {
809 retval = PTR_ERR(fsi);
810 goto out_free_file;
811 }
812
813 /* find a device that is not in use. */
814 mutex_lock(&devpts_mutex);
815 index = devpts_new_index(fsi);
816 mutex_unlock(&devpts_mutex);
817
818 retval = index;
819 if (index < 0)
820 goto out_put_fsi;
821
822
823 mutex_lock(&tty_mutex);
824 tty = tty_init_dev(ptm_driver, index);
825 /* The tty returned here is locked so we can safely
826 drop the mutex */
827 mutex_unlock(&tty_mutex);
828
829 retval = PTR_ERR(tty);
830 if (IS_ERR(tty))
831 goto out;
832
833 /*
834 * From here on out, the tty is "live", and the index and
835 * fsi will be killed/put by the tty_release()
836 */
837 set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
838 tty->driver_data = fsi;
839
840 tty_add_file(tty, filp);
841
842 dentry = devpts_pty_new(fsi, index, tty->link);
843 if (IS_ERR(dentry)) {
844 retval = PTR_ERR(dentry);
845 goto err_release;
846 }
847 tty->link->driver_data = dentry;
848
849 retval = ptm_driver->ops->open(tty, filp);
850 if (retval)
851 goto err_release;
852
853 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
854
855 tty_unlock(tty);
856 return 0;
857err_release:
858 tty_unlock(tty);
859 // This will also put-ref the fsi
860 tty_release(inode, filp);
861 return retval;
862out:
863 devpts_kill_index(fsi, index);
864out_put_fsi:
865 devpts_release(fsi);
866out_free_file:
867 tty_free_file(filp);
868 return retval;
869}
870
871static struct file_operations ptmx_fops __ro_after_init;
872
873static void __init unix98_pty_init(void)
874{
875 ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
876 TTY_DRIVER_RESET_TERMIOS |
877 TTY_DRIVER_REAL_RAW |
878 TTY_DRIVER_DYNAMIC_DEV |
879 TTY_DRIVER_DEVPTS_MEM |
880 TTY_DRIVER_DYNAMIC_ALLOC);
881 if (IS_ERR(ptm_driver))
882 panic("Couldn't allocate Unix98 ptm driver");
883 pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
884 TTY_DRIVER_RESET_TERMIOS |
885 TTY_DRIVER_REAL_RAW |
886 TTY_DRIVER_DYNAMIC_DEV |
887 TTY_DRIVER_DEVPTS_MEM |
888 TTY_DRIVER_DYNAMIC_ALLOC);
889 if (IS_ERR(pts_driver))
890 panic("Couldn't allocate Unix98 pts driver");
891
892 ptm_driver->driver_name = "pty_master";
893 ptm_driver->name = "ptm";
894 ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
895 ptm_driver->minor_start = 0;
896 ptm_driver->type = TTY_DRIVER_TYPE_PTY;
897 ptm_driver->subtype = PTY_TYPE_MASTER;
898 ptm_driver->init_termios = tty_std_termios;
899 ptm_driver->init_termios.c_iflag = 0;
900 ptm_driver->init_termios.c_oflag = 0;
901 ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
902 ptm_driver->init_termios.c_lflag = 0;
903 ptm_driver->init_termios.c_ispeed = 38400;
904 ptm_driver->init_termios.c_ospeed = 38400;
905 ptm_driver->other = pts_driver;
906 tty_set_operations(ptm_driver, &ptm_unix98_ops);
907
908 pts_driver->driver_name = "pty_slave";
909 pts_driver->name = "pts";
910 pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
911 pts_driver->minor_start = 0;
912 pts_driver->type = TTY_DRIVER_TYPE_PTY;
913 pts_driver->subtype = PTY_TYPE_SLAVE;
914 pts_driver->init_termios = tty_std_termios;
915 pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
916 pts_driver->init_termios.c_ispeed = 38400;
917 pts_driver->init_termios.c_ospeed = 38400;
918 pts_driver->other = ptm_driver;
919 tty_set_operations(pts_driver, &pty_unix98_ops);
920
921 if (tty_register_driver(ptm_driver))
922 panic("Couldn't register Unix98 ptm driver");
923 if (tty_register_driver(pts_driver))
924 panic("Couldn't register Unix98 pts driver");
925
926 /* Now create the /dev/ptmx special device */
927 tty_default_fops(&ptmx_fops);
928 ptmx_fops.open = ptmx_open;
929
930 cdev_init(&ptmx_cdev, &ptmx_fops);
931 if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
932 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
933 panic("Couldn't register /dev/ptmx driver");
934 device_create(&tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
935}
936
937#else
938static inline void unix98_pty_init(void) { }
939#endif
940
941static int __init pty_init(void)
942{
943 legacy_pty_init();
944 unix98_pty_init();
945 return 0;
946}
947device_initcall(pty_init);
1/*
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
6 *
7 */
8
9#include <linux/module.h>
10
11#include <linux/errno.h>
12#include <linux/interrupt.h>
13#include <linux/tty.h>
14#include <linux/tty_flip.h>
15#include <linux/fcntl.h>
16#include <linux/sched.h>
17#include <linux/string.h>
18#include <linux/major.h>
19#include <linux/mm.h>
20#include <linux/init.h>
21#include <linux/device.h>
22#include <linux/uaccess.h>
23#include <linux/bitops.h>
24#include <linux/devpts_fs.h>
25#include <linux/slab.h>
26#include <linux/mutex.h>
27
28
29#ifdef CONFIG_UNIX98_PTYS
30static struct tty_driver *ptm_driver;
31static struct tty_driver *pts_driver;
32static DEFINE_MUTEX(devpts_mutex);
33#endif
34
35static void pty_close(struct tty_struct *tty, struct file *filp)
36{
37 BUG_ON(!tty);
38 if (tty->driver->subtype == PTY_TYPE_MASTER)
39 WARN_ON(tty->count > 1);
40 else {
41 if (test_bit(TTY_IO_ERROR, &tty->flags))
42 return;
43 if (tty->count > 2)
44 return;
45 }
46 set_bit(TTY_IO_ERROR, &tty->flags);
47 wake_up_interruptible(&tty->read_wait);
48 wake_up_interruptible(&tty->write_wait);
49 tty->packet = 0;
50 /* Review - krefs on tty_link ?? */
51 if (!tty->link)
52 return;
53 set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
54 wake_up_interruptible(&tty->link->read_wait);
55 wake_up_interruptible(&tty->link->write_wait);
56 if (tty->driver->subtype == PTY_TYPE_MASTER) {
57 set_bit(TTY_OTHER_CLOSED, &tty->flags);
58#ifdef CONFIG_UNIX98_PTYS
59 if (tty->driver == ptm_driver) {
60 mutex_lock(&devpts_mutex);
61 if (tty->link->driver_data)
62 devpts_pty_kill(tty->link->driver_data);
63 mutex_unlock(&devpts_mutex);
64 }
65#endif
66 tty_unlock(tty);
67 tty_vhangup(tty->link);
68 tty_lock(tty);
69 }
70}
71
72/*
73 * The unthrottle routine is called by the line discipline to signal
74 * that it can receive more characters. For PTY's, the TTY_THROTTLED
75 * flag is always set, to force the line discipline to always call the
76 * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
77 * characters in the queue. This is necessary since each time this
78 * happens, we need to wake up any sleeping processes that could be
79 * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
80 * for the pty buffer to be drained.
81 */
82static void pty_unthrottle(struct tty_struct *tty)
83{
84 tty_wakeup(tty->link);
85 set_bit(TTY_THROTTLED, &tty->flags);
86}
87
88/**
89 * pty_space - report space left for writing
90 * @to: tty we are writing into
91 *
92 * Limit the buffer space used by ptys to 8k.
93 */
94
95static int pty_space(struct tty_struct *to)
96{
97 int n = tty_buffer_space_avail(to->port);
98 return min(n, 8192);
99}
100
101/**
102 * pty_write - write to a pty
103 * @tty: the tty we write from
104 * @buf: kernel buffer of data
105 * @count: bytes to write
106 *
107 * Our "hardware" write method. Data is coming from the ldisc which
108 * may be in a non sleeping state. We simply throw this at the other
109 * end of the link as if we were an IRQ handler receiving stuff for
110 * the other side of the pty/tty pair.
111 */
112
113static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
114{
115 struct tty_struct *to = tty->link;
116
117 if (tty->stopped)
118 return 0;
119
120 if (c > 0) {
121 /* Stuff the data into the input queue of the other end */
122 c = tty_insert_flip_string(to->port, buf, c);
123 /* And shovel */
124 if (c)
125 tty_flip_buffer_push(to->port);
126 }
127 return c;
128}
129
130/**
131 * pty_write_room - write space
132 * @tty: tty we are writing from
133 *
134 * Report how many bytes the ldisc can send into the queue for
135 * the other device.
136 */
137
138static int pty_write_room(struct tty_struct *tty)
139{
140 if (tty->stopped)
141 return 0;
142 return pty_space(tty->link);
143}
144
145/**
146 * pty_chars_in_buffer - characters currently in our tx queue
147 * @tty: our tty
148 *
149 * Report how much we have in the transmit queue. As everything is
150 * instantly at the other end this is easy to implement.
151 */
152
153static int pty_chars_in_buffer(struct tty_struct *tty)
154{
155 return 0;
156}
157
158/* Set the lock flag on a pty */
159static int pty_set_lock(struct tty_struct *tty, int __user *arg)
160{
161 int val;
162 if (get_user(val, arg))
163 return -EFAULT;
164 if (val)
165 set_bit(TTY_PTY_LOCK, &tty->flags);
166 else
167 clear_bit(TTY_PTY_LOCK, &tty->flags);
168 return 0;
169}
170
171static int pty_get_lock(struct tty_struct *tty, int __user *arg)
172{
173 int locked = test_bit(TTY_PTY_LOCK, &tty->flags);
174 return put_user(locked, arg);
175}
176
177/* Set the packet mode on a pty */
178static int pty_set_pktmode(struct tty_struct *tty, int __user *arg)
179{
180 unsigned long flags;
181 int pktmode;
182
183 if (get_user(pktmode, arg))
184 return -EFAULT;
185
186 spin_lock_irqsave(&tty->ctrl_lock, flags);
187 if (pktmode) {
188 if (!tty->packet) {
189 tty->packet = 1;
190 tty->link->ctrl_status = 0;
191 }
192 } else
193 tty->packet = 0;
194 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
195
196 return 0;
197}
198
199/* Get the packet mode of a pty */
200static int pty_get_pktmode(struct tty_struct *tty, int __user *arg)
201{
202 int pktmode = tty->packet;
203 return put_user(pktmode, arg);
204}
205
206/* Send a signal to the slave */
207static int pty_signal(struct tty_struct *tty, int sig)
208{
209 unsigned long flags;
210 struct pid *pgrp;
211
212 if (tty->link) {
213 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
214 pgrp = get_pid(tty->link->pgrp);
215 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
216
217 kill_pgrp(pgrp, sig, 1);
218 put_pid(pgrp);
219 }
220 return 0;
221}
222
223static void pty_flush_buffer(struct tty_struct *tty)
224{
225 struct tty_struct *to = tty->link;
226 unsigned long flags;
227
228 if (!to)
229 return;
230 /* tty_buffer_flush(to); FIXME */
231 if (to->packet) {
232 spin_lock_irqsave(&tty->ctrl_lock, flags);
233 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
234 wake_up_interruptible(&to->read_wait);
235 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
236 }
237}
238
239static int pty_open(struct tty_struct *tty, struct file *filp)
240{
241 if (!tty || !tty->link)
242 return -ENODEV;
243
244 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
245 goto out;
246 if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
247 goto out;
248 if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1)
249 goto out;
250
251 clear_bit(TTY_IO_ERROR, &tty->flags);
252 clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
253 set_bit(TTY_THROTTLED, &tty->flags);
254 return 0;
255
256out:
257 set_bit(TTY_IO_ERROR, &tty->flags);
258 return -EIO;
259}
260
261static void pty_set_termios(struct tty_struct *tty,
262 struct ktermios *old_termios)
263{
264 tty->termios.c_cflag &= ~(CSIZE | PARENB);
265 tty->termios.c_cflag |= (CS8 | CREAD);
266}
267
268/**
269 * pty_do_resize - resize event
270 * @tty: tty being resized
271 * @ws: window size being set.
272 *
273 * Update the termios variables and send the necessary signals to
274 * peform a terminal resize correctly
275 */
276
277static int pty_resize(struct tty_struct *tty, struct winsize *ws)
278{
279 struct pid *pgrp, *rpgrp;
280 unsigned long flags;
281 struct tty_struct *pty = tty->link;
282
283 /* For a PTY we need to lock the tty side */
284 mutex_lock(&tty->winsize_mutex);
285 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
286 goto done;
287
288 /* Get the PID values and reference them so we can
289 avoid holding the tty ctrl lock while sending signals.
290 We need to lock these individually however. */
291
292 spin_lock_irqsave(&tty->ctrl_lock, flags);
293 pgrp = get_pid(tty->pgrp);
294 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
295
296 spin_lock_irqsave(&pty->ctrl_lock, flags);
297 rpgrp = get_pid(pty->pgrp);
298 spin_unlock_irqrestore(&pty->ctrl_lock, flags);
299
300 if (pgrp)
301 kill_pgrp(pgrp, SIGWINCH, 1);
302 if (rpgrp != pgrp && rpgrp)
303 kill_pgrp(rpgrp, SIGWINCH, 1);
304
305 put_pid(pgrp);
306 put_pid(rpgrp);
307
308 tty->winsize = *ws;
309 pty->winsize = *ws; /* Never used so will go away soon */
310done:
311 mutex_unlock(&tty->winsize_mutex);
312 return 0;
313}
314
315/**
316 * pty_common_install - set up the pty pair
317 * @driver: the pty driver
318 * @tty: the tty being instantiated
319 * @bool: legacy, true if this is BSD style
320 *
321 * Perform the initial set up for the tty/pty pair. Called from the
322 * tty layer when the port is first opened.
323 *
324 * Locking: the caller must hold the tty_mutex
325 */
326static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
327 bool legacy)
328{
329 struct tty_struct *o_tty;
330 struct tty_port *ports[2];
331 int idx = tty->index;
332 int retval = -ENOMEM;
333
334 o_tty = alloc_tty_struct();
335 if (!o_tty)
336 goto err;
337 ports[0] = kmalloc(sizeof **ports, GFP_KERNEL);
338 ports[1] = kmalloc(sizeof **ports, GFP_KERNEL);
339 if (!ports[0] || !ports[1])
340 goto err_free_tty;
341 if (!try_module_get(driver->other->owner)) {
342 /* This cannot in fact currently happen */
343 goto err_free_tty;
344 }
345 initialize_tty_struct(o_tty, driver->other, idx);
346
347 if (legacy) {
348 /* We always use new tty termios data so we can do this
349 the easy way .. */
350 retval = tty_init_termios(tty);
351 if (retval)
352 goto err_deinit_tty;
353
354 retval = tty_init_termios(o_tty);
355 if (retval)
356 goto err_free_termios;
357
358 driver->other->ttys[idx] = o_tty;
359 driver->ttys[idx] = tty;
360 } else {
361 memset(&tty->termios_locked, 0, sizeof(tty->termios_locked));
362 tty->termios = driver->init_termios;
363 memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked));
364 o_tty->termios = driver->other->init_termios;
365 }
366
367 /*
368 * Everything allocated ... set up the o_tty structure.
369 */
370 tty_driver_kref_get(driver->other);
371 if (driver->subtype == PTY_TYPE_MASTER)
372 o_tty->count++;
373 /* Establish the links in both directions */
374 tty->link = o_tty;
375 o_tty->link = tty;
376 tty_port_init(ports[0]);
377 tty_port_init(ports[1]);
378 o_tty->port = ports[0];
379 tty->port = ports[1];
380 o_tty->port->itty = o_tty;
381
382 tty_driver_kref_get(driver);
383 tty->count++;
384 return 0;
385err_free_termios:
386 if (legacy)
387 tty_free_termios(tty);
388err_deinit_tty:
389 deinitialize_tty_struct(o_tty);
390 module_put(o_tty->driver->owner);
391err_free_tty:
392 kfree(ports[0]);
393 kfree(ports[1]);
394 free_tty_struct(o_tty);
395err:
396 return retval;
397}
398
399static void pty_cleanup(struct tty_struct *tty)
400{
401 tty_port_put(tty->port);
402}
403
404/* Traditional BSD devices */
405#ifdef CONFIG_LEGACY_PTYS
406
407static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
408{
409 return pty_common_install(driver, tty, true);
410}
411
412static void pty_remove(struct tty_driver *driver, struct tty_struct *tty)
413{
414 struct tty_struct *pair = tty->link;
415 driver->ttys[tty->index] = NULL;
416 if (pair)
417 pair->driver->ttys[pair->index] = NULL;
418}
419
420static int pty_bsd_ioctl(struct tty_struct *tty,
421 unsigned int cmd, unsigned long arg)
422{
423 switch (cmd) {
424 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
425 return pty_set_lock(tty, (int __user *) arg);
426 case TIOCGPTLCK: /* Get PT Lock status */
427 return pty_get_lock(tty, (int __user *)arg);
428 case TIOCPKT: /* Set PT packet mode */
429 return pty_set_pktmode(tty, (int __user *)arg);
430 case TIOCGPKT: /* Get PT packet mode */
431 return pty_get_pktmode(tty, (int __user *)arg);
432 case TIOCSIG: /* Send signal to other side of pty */
433 return pty_signal(tty, (int) arg);
434 case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */
435 return -EINVAL;
436 }
437 return -ENOIOCTLCMD;
438}
439
440static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
441module_param(legacy_count, int, 0);
442
443/*
444 * The master side of a pty can do TIOCSPTLCK and thus
445 * has pty_bsd_ioctl.
446 */
447static const struct tty_operations master_pty_ops_bsd = {
448 .install = pty_install,
449 .open = pty_open,
450 .close = pty_close,
451 .write = pty_write,
452 .write_room = pty_write_room,
453 .flush_buffer = pty_flush_buffer,
454 .chars_in_buffer = pty_chars_in_buffer,
455 .unthrottle = pty_unthrottle,
456 .set_termios = pty_set_termios,
457 .ioctl = pty_bsd_ioctl,
458 .cleanup = pty_cleanup,
459 .resize = pty_resize,
460 .remove = pty_remove
461};
462
463static const struct tty_operations slave_pty_ops_bsd = {
464 .install = pty_install,
465 .open = pty_open,
466 .close = pty_close,
467 .write = pty_write,
468 .write_room = pty_write_room,
469 .flush_buffer = pty_flush_buffer,
470 .chars_in_buffer = pty_chars_in_buffer,
471 .unthrottle = pty_unthrottle,
472 .set_termios = pty_set_termios,
473 .cleanup = pty_cleanup,
474 .resize = pty_resize,
475 .remove = pty_remove
476};
477
478static void __init legacy_pty_init(void)
479{
480 struct tty_driver *pty_driver, *pty_slave_driver;
481
482 if (legacy_count <= 0)
483 return;
484
485 pty_driver = tty_alloc_driver(legacy_count,
486 TTY_DRIVER_RESET_TERMIOS |
487 TTY_DRIVER_REAL_RAW |
488 TTY_DRIVER_DYNAMIC_ALLOC);
489 if (IS_ERR(pty_driver))
490 panic("Couldn't allocate pty driver");
491
492 pty_slave_driver = tty_alloc_driver(legacy_count,
493 TTY_DRIVER_RESET_TERMIOS |
494 TTY_DRIVER_REAL_RAW |
495 TTY_DRIVER_DYNAMIC_ALLOC);
496 if (IS_ERR(pty_slave_driver))
497 panic("Couldn't allocate pty slave driver");
498
499 pty_driver->driver_name = "pty_master";
500 pty_driver->name = "pty";
501 pty_driver->major = PTY_MASTER_MAJOR;
502 pty_driver->minor_start = 0;
503 pty_driver->type = TTY_DRIVER_TYPE_PTY;
504 pty_driver->subtype = PTY_TYPE_MASTER;
505 pty_driver->init_termios = tty_std_termios;
506 pty_driver->init_termios.c_iflag = 0;
507 pty_driver->init_termios.c_oflag = 0;
508 pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
509 pty_driver->init_termios.c_lflag = 0;
510 pty_driver->init_termios.c_ispeed = 38400;
511 pty_driver->init_termios.c_ospeed = 38400;
512 pty_driver->other = pty_slave_driver;
513 tty_set_operations(pty_driver, &master_pty_ops_bsd);
514
515 pty_slave_driver->driver_name = "pty_slave";
516 pty_slave_driver->name = "ttyp";
517 pty_slave_driver->major = PTY_SLAVE_MAJOR;
518 pty_slave_driver->minor_start = 0;
519 pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
520 pty_slave_driver->subtype = PTY_TYPE_SLAVE;
521 pty_slave_driver->init_termios = tty_std_termios;
522 pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
523 pty_slave_driver->init_termios.c_ispeed = 38400;
524 pty_slave_driver->init_termios.c_ospeed = 38400;
525 pty_slave_driver->other = pty_driver;
526 tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
527
528 if (tty_register_driver(pty_driver))
529 panic("Couldn't register pty driver");
530 if (tty_register_driver(pty_slave_driver))
531 panic("Couldn't register pty slave driver");
532}
533#else
534static inline void legacy_pty_init(void) { }
535#endif
536
537/* Unix98 devices */
538#ifdef CONFIG_UNIX98_PTYS
539
540static struct cdev ptmx_cdev;
541
542static int pty_unix98_ioctl(struct tty_struct *tty,
543 unsigned int cmd, unsigned long arg)
544{
545 switch (cmd) {
546 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
547 return pty_set_lock(tty, (int __user *)arg);
548 case TIOCGPTLCK: /* Get PT Lock status */
549 return pty_get_lock(tty, (int __user *)arg);
550 case TIOCPKT: /* Set PT packet mode */
551 return pty_set_pktmode(tty, (int __user *)arg);
552 case TIOCGPKT: /* Get PT packet mode */
553 return pty_get_pktmode(tty, (int __user *)arg);
554 case TIOCGPTN: /* Get PT Number */
555 return put_user(tty->index, (unsigned int __user *)arg);
556 case TIOCSIG: /* Send signal to other side of pty */
557 return pty_signal(tty, (int) arg);
558 }
559
560 return -ENOIOCTLCMD;
561}
562
563/**
564 * ptm_unix98_lookup - find a pty master
565 * @driver: ptm driver
566 * @idx: tty index
567 *
568 * Look up a pty master device. Called under the tty_mutex for now.
569 * This provides our locking.
570 */
571
572static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
573 struct inode *ptm_inode, int idx)
574{
575 /* Master must be open via /dev/ptmx */
576 return ERR_PTR(-EIO);
577}
578
579/**
580 * pts_unix98_lookup - find a pty slave
581 * @driver: pts driver
582 * @idx: tty index
583 *
584 * Look up a pty master device. Called under the tty_mutex for now.
585 * This provides our locking for the tty pointer.
586 */
587
588static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
589 struct inode *pts_inode, int idx)
590{
591 struct tty_struct *tty;
592
593 mutex_lock(&devpts_mutex);
594 tty = devpts_get_priv(pts_inode);
595 mutex_unlock(&devpts_mutex);
596 /* Master must be open before slave */
597 if (!tty)
598 return ERR_PTR(-EIO);
599 return tty;
600}
601
602/* We have no need to install and remove our tty objects as devpts does all
603 the work for us */
604
605static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
606{
607 return pty_common_install(driver, tty, false);
608}
609
610static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
611{
612}
613
614/* this is called once with whichever end is closed last */
615static void pty_unix98_shutdown(struct tty_struct *tty)
616{
617 devpts_kill_index(tty->driver_data, tty->index);
618}
619
620static const struct tty_operations ptm_unix98_ops = {
621 .lookup = ptm_unix98_lookup,
622 .install = pty_unix98_install,
623 .remove = pty_unix98_remove,
624 .open = pty_open,
625 .close = pty_close,
626 .write = pty_write,
627 .write_room = pty_write_room,
628 .flush_buffer = pty_flush_buffer,
629 .chars_in_buffer = pty_chars_in_buffer,
630 .unthrottle = pty_unthrottle,
631 .set_termios = pty_set_termios,
632 .ioctl = pty_unix98_ioctl,
633 .resize = pty_resize,
634 .shutdown = pty_unix98_shutdown,
635 .cleanup = pty_cleanup
636};
637
638static const struct tty_operations pty_unix98_ops = {
639 .lookup = pts_unix98_lookup,
640 .install = pty_unix98_install,
641 .remove = pty_unix98_remove,
642 .open = pty_open,
643 .close = pty_close,
644 .write = pty_write,
645 .write_room = pty_write_room,
646 .flush_buffer = pty_flush_buffer,
647 .chars_in_buffer = pty_chars_in_buffer,
648 .unthrottle = pty_unthrottle,
649 .set_termios = pty_set_termios,
650 .shutdown = pty_unix98_shutdown,
651 .cleanup = pty_cleanup,
652};
653
654/**
655 * ptmx_open - open a unix 98 pty master
656 * @inode: inode of device file
657 * @filp: file pointer to tty
658 *
659 * Allocate a unix98 pty master device from the ptmx driver.
660 *
661 * Locking: tty_mutex protects the init_dev work. tty->count should
662 * protect the rest.
663 * allocated_ptys_lock handles the list of free pty numbers
664 */
665
666static int ptmx_open(struct inode *inode, struct file *filp)
667{
668 struct tty_struct *tty;
669 struct inode *slave_inode;
670 int retval;
671 int index;
672
673 nonseekable_open(inode, filp);
674
675 /* We refuse fsnotify events on ptmx, since it's a shared resource */
676 filp->f_mode |= FMODE_NONOTIFY;
677
678 retval = tty_alloc_file(filp);
679 if (retval)
680 return retval;
681
682 /* find a device that is not in use. */
683 mutex_lock(&devpts_mutex);
684 index = devpts_new_index(inode);
685 if (index < 0) {
686 retval = index;
687 mutex_unlock(&devpts_mutex);
688 goto err_file;
689 }
690
691 mutex_unlock(&devpts_mutex);
692
693 mutex_lock(&tty_mutex);
694 tty = tty_init_dev(ptm_driver, index);
695
696 if (IS_ERR(tty)) {
697 retval = PTR_ERR(tty);
698 goto out;
699 }
700
701 /* The tty returned here is locked so we can safely
702 drop the mutex */
703 mutex_unlock(&tty_mutex);
704
705 set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
706 tty->driver_data = inode;
707
708 tty_add_file(tty, filp);
709
710 slave_inode = devpts_pty_new(inode,
711 MKDEV(UNIX98_PTY_SLAVE_MAJOR, index), index,
712 tty->link);
713 if (IS_ERR(slave_inode)) {
714 retval = PTR_ERR(slave_inode);
715 goto err_release;
716 }
717 tty->link->driver_data = slave_inode;
718
719 retval = ptm_driver->ops->open(tty, filp);
720 if (retval)
721 goto err_release;
722
723 tty_unlock(tty);
724 return 0;
725err_release:
726 tty_unlock(tty);
727 tty_release(inode, filp);
728 return retval;
729out:
730 mutex_unlock(&tty_mutex);
731 devpts_kill_index(inode, index);
732err_file:
733 tty_free_file(filp);
734 return retval;
735}
736
737static struct file_operations ptmx_fops;
738
739static void __init unix98_pty_init(void)
740{
741 ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
742 TTY_DRIVER_RESET_TERMIOS |
743 TTY_DRIVER_REAL_RAW |
744 TTY_DRIVER_DYNAMIC_DEV |
745 TTY_DRIVER_DEVPTS_MEM |
746 TTY_DRIVER_DYNAMIC_ALLOC);
747 if (IS_ERR(ptm_driver))
748 panic("Couldn't allocate Unix98 ptm driver");
749 pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
750 TTY_DRIVER_RESET_TERMIOS |
751 TTY_DRIVER_REAL_RAW |
752 TTY_DRIVER_DYNAMIC_DEV |
753 TTY_DRIVER_DEVPTS_MEM |
754 TTY_DRIVER_DYNAMIC_ALLOC);
755 if (IS_ERR(pts_driver))
756 panic("Couldn't allocate Unix98 pts driver");
757
758 ptm_driver->driver_name = "pty_master";
759 ptm_driver->name = "ptm";
760 ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
761 ptm_driver->minor_start = 0;
762 ptm_driver->type = TTY_DRIVER_TYPE_PTY;
763 ptm_driver->subtype = PTY_TYPE_MASTER;
764 ptm_driver->init_termios = tty_std_termios;
765 ptm_driver->init_termios.c_iflag = 0;
766 ptm_driver->init_termios.c_oflag = 0;
767 ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
768 ptm_driver->init_termios.c_lflag = 0;
769 ptm_driver->init_termios.c_ispeed = 38400;
770 ptm_driver->init_termios.c_ospeed = 38400;
771 ptm_driver->other = pts_driver;
772 tty_set_operations(ptm_driver, &ptm_unix98_ops);
773
774 pts_driver->driver_name = "pty_slave";
775 pts_driver->name = "pts";
776 pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
777 pts_driver->minor_start = 0;
778 pts_driver->type = TTY_DRIVER_TYPE_PTY;
779 pts_driver->subtype = PTY_TYPE_SLAVE;
780 pts_driver->init_termios = tty_std_termios;
781 pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
782 pts_driver->init_termios.c_ispeed = 38400;
783 pts_driver->init_termios.c_ospeed = 38400;
784 pts_driver->other = ptm_driver;
785 tty_set_operations(pts_driver, &pty_unix98_ops);
786
787 if (tty_register_driver(ptm_driver))
788 panic("Couldn't register Unix98 ptm driver");
789 if (tty_register_driver(pts_driver))
790 panic("Couldn't register Unix98 pts driver");
791
792 /* Now create the /dev/ptmx special device */
793 tty_default_fops(&ptmx_fops);
794 ptmx_fops.open = ptmx_open;
795
796 cdev_init(&ptmx_cdev, &ptmx_fops);
797 if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
798 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
799 panic("Couldn't register /dev/ptmx driver");
800 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
801}
802
803#else
804static inline void unix98_pty_init(void) { }
805#endif
806
807static int __init pty_init(void)
808{
809 legacy_pty_init();
810 unix98_pty_init();
811 return 0;
812}
813module_init(pty_init);