2 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Added support for a Unix98-style ptmx device.
5 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
9 #include <linux/module.h>
10 #include <linux/errno.h>
11 #include <linux/interrupt.h>
12 #include <linux/tty.h>
13 #include <linux/tty_flip.h>
14 #include <linux/fcntl.h>
15 #include <linux/sched/signal.h>
16 #include <linux/string.h>
17 #include <linux/major.h>
19 #include <linux/init.h>
20 #include <linux/device.h>
21 #include <linux/uaccess.h>
22 #include <linux/bitops.h>
23 #include <linux/devpts_fs.h>
24 #include <linux/slab.h>
25 #include <linux/mutex.h>
26 #include <linux/poll.h>
27 #include <linux/mount.h>
28 #include <linux/file.h>
29 #include <linux/ioctl.h>
31 #undef TTY_DEBUG_HANGUP
32 #ifdef TTY_DEBUG_HANGUP
33 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
35 # define tty_debug_hangup(tty, f, args...) do {} while (0)
38 #ifdef CONFIG_UNIX98_PTYS
39 static struct tty_driver
*ptm_driver
;
40 static struct tty_driver
*pts_driver
;
41 static DEFINE_MUTEX(devpts_mutex
);
44 static void pty_close(struct tty_struct
*tty
, struct file
*filp
)
47 if (tty
->driver
->subtype
== PTY_TYPE_MASTER
)
48 WARN_ON(tty
->count
> 1);
50 if (tty_io_error(tty
))
55 set_bit(TTY_IO_ERROR
, &tty
->flags
);
56 wake_up_interruptible(&tty
->read_wait
);
57 wake_up_interruptible(&tty
->write_wait
);
58 spin_lock_irq(&tty
->ctrl_lock
);
60 spin_unlock_irq(&tty
->ctrl_lock
);
61 /* Review - krefs on tty_link ?? */
64 set_bit(TTY_OTHER_CLOSED
, &tty
->link
->flags
);
65 wake_up_interruptible(&tty
->link
->read_wait
);
66 wake_up_interruptible(&tty
->link
->write_wait
);
67 if (tty
->driver
->subtype
== PTY_TYPE_MASTER
) {
68 set_bit(TTY_OTHER_CLOSED
, &tty
->flags
);
69 #ifdef CONFIG_UNIX98_PTYS
70 if (tty
->driver
== ptm_driver
) {
71 mutex_lock(&devpts_mutex
);
72 if (tty
->link
->driver_data
) {
73 struct path
*path
= tty
->link
->driver_data
;
75 devpts_pty_kill(path
->dentry
);
79 mutex_unlock(&devpts_mutex
);
82 tty_vhangup(tty
->link
);
87 * The unthrottle routine is called by the line discipline to signal
88 * that it can receive more characters. For PTY's, the TTY_THROTTLED
89 * flag is always set, to force the line discipline to always call the
90 * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
91 * characters in the queue. This is necessary since each time this
92 * happens, we need to wake up any sleeping processes that could be
93 * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
94 * for the pty buffer to be drained.
96 static void pty_unthrottle(struct tty_struct
*tty
)
98 tty_wakeup(tty
->link
);
99 set_bit(TTY_THROTTLED
, &tty
->flags
);
103 * pty_write - write to a pty
104 * @tty: the tty we write from
105 * @buf: kernel buffer of data
106 * @count: bytes to write
108 * Our "hardware" write method. Data is coming from the ldisc which
109 * may be in a non sleeping state. We simply throw this at the other
110 * end of the link as if we were an IRQ handler receiving stuff for
111 * the other side of the pty/tty pair.
114 static int pty_write(struct tty_struct
*tty
, const unsigned char *buf
, int c
)
116 struct tty_struct
*to
= tty
->link
;
122 /* Stuff the data into the input queue of the other end */
123 c
= tty_insert_flip_string(to
->port
, buf
, c
);
126 tty_flip_buffer_push(to
->port
);
132 * pty_write_room - write space
133 * @tty: tty we are writing from
135 * Report how many bytes the ldisc can send into the queue for
139 static int pty_write_room(struct tty_struct
*tty
)
143 return tty_buffer_space_avail(tty
->link
->port
);
147 * pty_chars_in_buffer - characters currently in our tx queue
150 * Report how much we have in the transmit queue. As everything is
151 * instantly at the other end this is easy to implement.
154 static int pty_chars_in_buffer(struct tty_struct
*tty
)
159 /* Set the lock flag on a pty */
160 static int pty_set_lock(struct tty_struct
*tty
, int __user
*arg
)
163 if (get_user(val
, arg
))
166 set_bit(TTY_PTY_LOCK
, &tty
->flags
);
168 clear_bit(TTY_PTY_LOCK
, &tty
->flags
);
172 static int pty_get_lock(struct tty_struct
*tty
, int __user
*arg
)
174 int locked
= test_bit(TTY_PTY_LOCK
, &tty
->flags
);
175 return put_user(locked
, arg
);
178 /* Set the packet mode on a pty */
179 static int pty_set_pktmode(struct tty_struct
*tty
, int __user
*arg
)
183 if (get_user(pktmode
, arg
))
186 spin_lock_irq(&tty
->ctrl_lock
);
189 tty
->link
->ctrl_status
= 0;
195 spin_unlock_irq(&tty
->ctrl_lock
);
200 /* Get the packet mode of a pty */
201 static int pty_get_pktmode(struct tty_struct
*tty
, int __user
*arg
)
203 int pktmode
= tty
->packet
;
204 return put_user(pktmode
, arg
);
207 /* Send a signal to the slave */
208 static int pty_signal(struct tty_struct
*tty
, int sig
)
212 if (sig
!= SIGINT
&& sig
!= SIGQUIT
&& sig
!= SIGTSTP
)
216 pgrp
= tty_get_pgrp(tty
->link
);
218 kill_pgrp(pgrp
, sig
, 1);
224 static void pty_flush_buffer(struct tty_struct
*tty
)
226 struct tty_struct
*to
= tty
->link
;
231 tty_buffer_flush(to
, NULL
);
233 spin_lock_irq(&tty
->ctrl_lock
);
234 tty
->ctrl_status
|= TIOCPKT_FLUSHWRITE
;
235 wake_up_interruptible(&to
->read_wait
);
236 spin_unlock_irq(&tty
->ctrl_lock
);
240 static int pty_open(struct tty_struct
*tty
, struct file
*filp
)
242 if (!tty
|| !tty
->link
)
245 if (test_bit(TTY_OTHER_CLOSED
, &tty
->flags
))
247 if (test_bit(TTY_PTY_LOCK
, &tty
->link
->flags
))
249 if (tty
->driver
->subtype
== PTY_TYPE_SLAVE
&& tty
->link
->count
!= 1)
252 clear_bit(TTY_IO_ERROR
, &tty
->flags
);
253 clear_bit(TTY_OTHER_CLOSED
, &tty
->link
->flags
);
254 set_bit(TTY_THROTTLED
, &tty
->flags
);
258 set_bit(TTY_IO_ERROR
, &tty
->flags
);
262 static void pty_set_termios(struct tty_struct
*tty
,
263 struct ktermios
*old_termios
)
265 /* See if packet mode change of state. */
266 if (tty
->link
&& tty
->link
->packet
) {
267 int extproc
= (old_termios
->c_lflag
& EXTPROC
) | L_EXTPROC(tty
);
268 int old_flow
= ((old_termios
->c_iflag
& IXON
) &&
269 (old_termios
->c_cc
[VSTOP
] == '\023') &&
270 (old_termios
->c_cc
[VSTART
] == '\021'));
271 int new_flow
= (I_IXON(tty
) &&
272 STOP_CHAR(tty
) == '\023' &&
273 START_CHAR(tty
) == '\021');
274 if ((old_flow
!= new_flow
) || extproc
) {
275 spin_lock_irq(&tty
->ctrl_lock
);
276 if (old_flow
!= new_flow
) {
277 tty
->ctrl_status
&= ~(TIOCPKT_DOSTOP
| TIOCPKT_NOSTOP
);
279 tty
->ctrl_status
|= TIOCPKT_DOSTOP
;
281 tty
->ctrl_status
|= TIOCPKT_NOSTOP
;
284 tty
->ctrl_status
|= TIOCPKT_IOCTL
;
285 spin_unlock_irq(&tty
->ctrl_lock
);
286 wake_up_interruptible(&tty
->link
->read_wait
);
290 tty
->termios
.c_cflag
&= ~(CSIZE
| PARENB
);
291 tty
->termios
.c_cflag
|= (CS8
| CREAD
);
295 * pty_do_resize - resize event
296 * @tty: tty being resized
297 * @ws: window size being set.
299 * Update the termios variables and send the necessary signals to
300 * peform a terminal resize correctly
303 static int pty_resize(struct tty_struct
*tty
, struct winsize
*ws
)
305 struct pid
*pgrp
, *rpgrp
;
306 struct tty_struct
*pty
= tty
->link
;
308 /* For a PTY we need to lock the tty side */
309 mutex_lock(&tty
->winsize_mutex
);
310 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
313 /* Signal the foreground process group of both ptys */
314 pgrp
= tty_get_pgrp(tty
);
315 rpgrp
= tty_get_pgrp(pty
);
318 kill_pgrp(pgrp
, SIGWINCH
, 1);
319 if (rpgrp
!= pgrp
&& rpgrp
)
320 kill_pgrp(rpgrp
, SIGWINCH
, 1);
326 pty
->winsize
= *ws
; /* Never used so will go away soon */
328 mutex_unlock(&tty
->winsize_mutex
);
333 * pty_start - start() handler
334 * pty_stop - stop() handler
335 * @tty: tty being flow-controlled
337 * Propagates the TIOCPKT status to the master pty.
339 * NB: only the master pty can be in packet mode so only the slave
340 * needs start()/stop() handlers
342 static void pty_start(struct tty_struct
*tty
)
346 if (tty
->link
&& tty
->link
->packet
) {
347 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
348 tty
->ctrl_status
&= ~TIOCPKT_STOP
;
349 tty
->ctrl_status
|= TIOCPKT_START
;
350 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
351 wake_up_interruptible_poll(&tty
->link
->read_wait
, POLLIN
);
355 static void pty_stop(struct tty_struct
*tty
)
359 if (tty
->link
&& tty
->link
->packet
) {
360 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
361 tty
->ctrl_status
&= ~TIOCPKT_START
;
362 tty
->ctrl_status
|= TIOCPKT_STOP
;
363 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
364 wake_up_interruptible_poll(&tty
->link
->read_wait
, POLLIN
);
369 * pty_common_install - set up the pty pair
370 * @driver: the pty driver
371 * @tty: the tty being instantiated
372 * @legacy: true if this is BSD style
374 * Perform the initial set up for the tty/pty pair. Called from the
375 * tty layer when the port is first opened.
377 * Locking: the caller must hold the tty_mutex
379 static int pty_common_install(struct tty_driver
*driver
, struct tty_struct
*tty
,
382 struct tty_struct
*o_tty
;
383 struct tty_port
*ports
[2];
384 int idx
= tty
->index
;
385 int retval
= -ENOMEM
;
387 /* Opening the slave first has always returned -EIO */
388 if (driver
->subtype
!= PTY_TYPE_MASTER
)
391 ports
[0] = kmalloc(sizeof **ports
, GFP_KERNEL
);
392 ports
[1] = kmalloc(sizeof **ports
, GFP_KERNEL
);
393 if (!ports
[0] || !ports
[1])
395 if (!try_module_get(driver
->other
->owner
)) {
396 /* This cannot in fact currently happen */
399 o_tty
= alloc_tty_struct(driver
->other
, idx
);
403 tty_set_lock_subclass(o_tty
);
404 lockdep_set_subclass(&o_tty
->termios_rwsem
, TTY_LOCK_SLAVE
);
407 /* We always use new tty termios data so we can do this
409 tty_init_termios(tty
);
410 tty_init_termios(o_tty
);
412 driver
->other
->ttys
[idx
] = o_tty
;
413 driver
->ttys
[idx
] = tty
;
415 memset(&tty
->termios_locked
, 0, sizeof(tty
->termios_locked
));
416 tty
->termios
= driver
->init_termios
;
417 memset(&o_tty
->termios_locked
, 0, sizeof(tty
->termios_locked
));
418 o_tty
->termios
= driver
->other
->init_termios
;
422 * Everything allocated ... set up the o_tty structure.
424 tty_driver_kref_get(driver
->other
);
425 /* Establish the links in both directions */
428 tty_port_init(ports
[0]);
429 tty_port_init(ports
[1]);
430 tty_buffer_set_limit(ports
[0], 8192);
431 tty_buffer_set_limit(ports
[1], 8192);
432 o_tty
->port
= ports
[0];
433 tty
->port
= ports
[1];
434 o_tty
->port
->itty
= o_tty
;
436 tty_buffer_set_lock_subclass(o_tty
->port
);
438 tty_driver_kref_get(driver
);
444 module_put(driver
->other
->owner
);
451 static void pty_cleanup(struct tty_struct
*tty
)
453 tty_port_put(tty
->port
);
456 /* Traditional BSD devices */
457 #ifdef CONFIG_LEGACY_PTYS
459 static int pty_install(struct tty_driver
*driver
, struct tty_struct
*tty
)
461 return pty_common_install(driver
, tty
, true);
464 static void pty_remove(struct tty_driver
*driver
, struct tty_struct
*tty
)
466 struct tty_struct
*pair
= tty
->link
;
467 driver
->ttys
[tty
->index
] = NULL
;
469 pair
->driver
->ttys
[pair
->index
] = NULL
;
472 static int pty_bsd_ioctl(struct tty_struct
*tty
,
473 unsigned int cmd
, unsigned long arg
)
476 case TIOCSPTLCK
: /* Set PT Lock (disallow slave open) */
477 return pty_set_lock(tty
, (int __user
*) arg
);
478 case TIOCGPTLCK
: /* Get PT Lock status */
479 return pty_get_lock(tty
, (int __user
*)arg
);
480 case TIOCPKT
: /* Set PT packet mode */
481 return pty_set_pktmode(tty
, (int __user
*)arg
);
482 case TIOCGPKT
: /* Get PT packet mode */
483 return pty_get_pktmode(tty
, (int __user
*)arg
);
484 case TIOCSIG
: /* Send signal to other side of pty */
485 return pty_signal(tty
, (int) arg
);
486 case TIOCGPTN
: /* TTY returns ENOTTY, but glibc expects EINVAL here */
492 static long pty_bsd_compat_ioctl(struct tty_struct
*tty
,
493 unsigned int cmd
, unsigned long arg
)
496 * PTY ioctls don't require any special translation between 32-bit and
497 * 64-bit userspace, they are already compatible.
499 return pty_bsd_ioctl(tty
, cmd
, arg
);
502 static int legacy_count
= CONFIG_LEGACY_PTY_COUNT
;
504 * not really modular, but the easiest way to keep compat with existing
505 * bootargs behaviour is to continue using module_param here.
507 module_param(legacy_count
, int, 0);
510 * The master side of a pty can do TIOCSPTLCK and thus
513 static const struct tty_operations master_pty_ops_bsd
= {
514 .install
= pty_install
,
518 .write_room
= pty_write_room
,
519 .flush_buffer
= pty_flush_buffer
,
520 .chars_in_buffer
= pty_chars_in_buffer
,
521 .unthrottle
= pty_unthrottle
,
522 .ioctl
= pty_bsd_ioctl
,
523 .compat_ioctl
= pty_bsd_compat_ioctl
,
524 .cleanup
= pty_cleanup
,
525 .resize
= pty_resize
,
529 static const struct tty_operations slave_pty_ops_bsd
= {
530 .install
= pty_install
,
534 .write_room
= pty_write_room
,
535 .flush_buffer
= pty_flush_buffer
,
536 .chars_in_buffer
= pty_chars_in_buffer
,
537 .unthrottle
= pty_unthrottle
,
538 .set_termios
= pty_set_termios
,
539 .cleanup
= pty_cleanup
,
540 .resize
= pty_resize
,
546 static void __init
legacy_pty_init(void)
548 struct tty_driver
*pty_driver
, *pty_slave_driver
;
550 if (legacy_count
<= 0)
553 pty_driver
= tty_alloc_driver(legacy_count
,
554 TTY_DRIVER_RESET_TERMIOS
|
555 TTY_DRIVER_REAL_RAW
|
556 TTY_DRIVER_DYNAMIC_ALLOC
);
557 if (IS_ERR(pty_driver
))
558 panic("Couldn't allocate pty driver");
560 pty_slave_driver
= tty_alloc_driver(legacy_count
,
561 TTY_DRIVER_RESET_TERMIOS
|
562 TTY_DRIVER_REAL_RAW
|
563 TTY_DRIVER_DYNAMIC_ALLOC
);
564 if (IS_ERR(pty_slave_driver
))
565 panic("Couldn't allocate pty slave driver");
567 pty_driver
->driver_name
= "pty_master";
568 pty_driver
->name
= "pty";
569 pty_driver
->major
= PTY_MASTER_MAJOR
;
570 pty_driver
->minor_start
= 0;
571 pty_driver
->type
= TTY_DRIVER_TYPE_PTY
;
572 pty_driver
->subtype
= PTY_TYPE_MASTER
;
573 pty_driver
->init_termios
= tty_std_termios
;
574 pty_driver
->init_termios
.c_iflag
= 0;
575 pty_driver
->init_termios
.c_oflag
= 0;
576 pty_driver
->init_termios
.c_cflag
= B38400
| CS8
| CREAD
;
577 pty_driver
->init_termios
.c_lflag
= 0;
578 pty_driver
->init_termios
.c_ispeed
= 38400;
579 pty_driver
->init_termios
.c_ospeed
= 38400;
580 pty_driver
->other
= pty_slave_driver
;
581 tty_set_operations(pty_driver
, &master_pty_ops_bsd
);
583 pty_slave_driver
->driver_name
= "pty_slave";
584 pty_slave_driver
->name
= "ttyp";
585 pty_slave_driver
->major
= PTY_SLAVE_MAJOR
;
586 pty_slave_driver
->minor_start
= 0;
587 pty_slave_driver
->type
= TTY_DRIVER_TYPE_PTY
;
588 pty_slave_driver
->subtype
= PTY_TYPE_SLAVE
;
589 pty_slave_driver
->init_termios
= tty_std_termios
;
590 pty_slave_driver
->init_termios
.c_cflag
= B38400
| CS8
| CREAD
;
591 pty_slave_driver
->init_termios
.c_ispeed
= 38400;
592 pty_slave_driver
->init_termios
.c_ospeed
= 38400;
593 pty_slave_driver
->other
= pty_driver
;
594 tty_set_operations(pty_slave_driver
, &slave_pty_ops_bsd
);
596 if (tty_register_driver(pty_driver
))
597 panic("Couldn't register pty driver");
598 if (tty_register_driver(pty_slave_driver
))
599 panic("Couldn't register pty slave driver");
602 static inline void legacy_pty_init(void) { }
606 #ifdef CONFIG_UNIX98_PTYS
607 static struct cdev ptmx_cdev
;
610 * pty_open_peer - open the peer of a pty
611 * @tty: the peer of the pty being opened
613 * Open the cached dentry in tty->link, providing a safe way for userspace
614 * to get the slave end of a pty (where they have the master fd and cannot
615 * access or trust the mount namespace /dev/pts was mounted inside).
617 static struct file
*pty_open_peer(struct tty_struct
*tty
, int flags
)
619 if (tty
->driver
->subtype
!= PTY_TYPE_MASTER
)
620 return ERR_PTR(-EIO
);
621 return dentry_open(tty
->link
->driver_data
, flags
, current_cred());
624 static int pty_get_peer(struct tty_struct
*tty
, int flags
)
627 struct file
*filp
= NULL
;
628 int retval
= -EINVAL
;
630 fd
= get_unused_fd_flags(0);
636 filp
= pty_open_peer(tty
, flags
);
638 retval
= PTR_ERR(filp
);
642 fd_install(fd
, filp
);
651 static int pty_unix98_ioctl(struct tty_struct
*tty
,
652 unsigned int cmd
, unsigned long arg
)
655 case TIOCSPTLCK
: /* Set PT Lock (disallow slave open) */
656 return pty_set_lock(tty
, (int __user
*)arg
);
657 case TIOCGPTLCK
: /* Get PT Lock status */
658 return pty_get_lock(tty
, (int __user
*)arg
);
659 case TIOCPKT
: /* Set PT packet mode */
660 return pty_set_pktmode(tty
, (int __user
*)arg
);
661 case TIOCGPKT
: /* Get PT packet mode */
662 return pty_get_pktmode(tty
, (int __user
*)arg
);
663 case TIOCGPTN
: /* Get PT Number */
664 return put_user(tty
->index
, (unsigned int __user
*)arg
);
665 case TIOCGPTPEER
: /* Open the other end */
666 return pty_get_peer(tty
, (int) arg
);
667 case TIOCSIG
: /* Send signal to other side of pty */
668 return pty_signal(tty
, (int) arg
);
674 static long pty_unix98_compat_ioctl(struct tty_struct
*tty
,
675 unsigned int cmd
, unsigned long arg
)
678 * PTY ioctls don't require any special translation between 32-bit and
679 * 64-bit userspace, they are already compatible.
681 return pty_unix98_ioctl(tty
, cmd
, arg
);
685 * ptm_unix98_lookup - find a pty master
686 * @driver: ptm driver
689 * Look up a pty master device. Called under the tty_mutex for now.
690 * This provides our locking.
693 static struct tty_struct
*ptm_unix98_lookup(struct tty_driver
*driver
,
694 struct file
*file
, int idx
)
696 /* Master must be open via /dev/ptmx */
697 return ERR_PTR(-EIO
);
701 * pts_unix98_lookup - find a pty slave
702 * @driver: pts driver
705 * Look up a pty master device. Called under the tty_mutex for now.
706 * This provides our locking for the tty pointer.
709 static struct tty_struct
*pts_unix98_lookup(struct tty_driver
*driver
,
710 struct file
*file
, int idx
)
712 struct tty_struct
*tty
;
714 mutex_lock(&devpts_mutex
);
715 tty
= devpts_get_priv(file
->f_path
.dentry
);
716 mutex_unlock(&devpts_mutex
);
717 /* Master must be open before slave */
719 return ERR_PTR(-EIO
);
723 static int pty_unix98_install(struct tty_driver
*driver
, struct tty_struct
*tty
)
725 return pty_common_install(driver
, tty
, false);
728 /* this is called once with whichever end is closed last */
729 static void pty_unix98_remove(struct tty_driver
*driver
, struct tty_struct
*tty
)
731 struct pts_fs_info
*fsi
;
733 if (tty
->driver
->subtype
== PTY_TYPE_MASTER
)
734 fsi
= tty
->driver_data
;
736 fsi
= tty
->link
->driver_data
;
739 devpts_kill_index(fsi
, tty
->index
);
744 static const struct tty_operations ptm_unix98_ops
= {
745 .lookup
= ptm_unix98_lookup
,
746 .install
= pty_unix98_install
,
747 .remove
= pty_unix98_remove
,
751 .write_room
= pty_write_room
,
752 .flush_buffer
= pty_flush_buffer
,
753 .chars_in_buffer
= pty_chars_in_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
761 static const struct tty_operations pty_unix98_ops
= {
762 .lookup
= pts_unix98_lookup
,
763 .install
= pty_unix98_install
,
764 .remove
= pty_unix98_remove
,
768 .write_room
= pty_write_room
,
769 .flush_buffer
= pty_flush_buffer
,
770 .chars_in_buffer
= pty_chars_in_buffer
,
771 .unthrottle
= pty_unthrottle
,
772 .set_termios
= pty_set_termios
,
775 .cleanup
= pty_cleanup
,
779 * ptmx_open - open a unix 98 pty master
780 * @inode: inode of device file
781 * @filp: file pointer to tty
783 * Allocate a unix98 pty master device from the ptmx driver.
785 * Locking: tty_mutex protects the init_dev work. tty->count should
787 * allocated_ptys_lock handles the list of free pty numbers
790 static int ptmx_open(struct inode
*inode
, struct file
*filp
)
792 struct pts_fs_info
*fsi
;
793 struct tty_struct
*tty
;
794 struct path
*pts_path
;
795 struct dentry
*dentry
;
799 nonseekable_open(inode
, filp
);
801 /* We refuse fsnotify events on ptmx, since it's a shared resource */
802 filp
->f_mode
|= FMODE_NONOTIFY
;
804 retval
= tty_alloc_file(filp
);
808 fsi
= devpts_acquire(filp
);
810 retval
= PTR_ERR(fsi
);
814 /* find a device that is not in use. */
815 mutex_lock(&devpts_mutex
);
816 index
= devpts_new_index(fsi
);
817 mutex_unlock(&devpts_mutex
);
824 mutex_lock(&tty_mutex
);
825 tty
= tty_init_dev(ptm_driver
, index
);
826 /* The tty returned here is locked so we can safely
828 mutex_unlock(&tty_mutex
);
830 retval
= PTR_ERR(tty
);
835 * From here on out, the tty is "live", and the index and
836 * fsi will be killed/put by the tty_release()
838 set_bit(TTY_PTY_LOCK
, &tty
->flags
); /* LOCK THE SLAVE */
839 tty
->driver_data
= fsi
;
841 tty_add_file(tty
, filp
);
843 dentry
= devpts_pty_new(fsi
, index
, tty
->link
);
844 if (IS_ERR(dentry
)) {
845 retval
= PTR_ERR(dentry
);
848 /* We need to cache a fake path for TIOCGPTPEER. */
849 pts_path
= kmalloc(sizeof(struct path
), GFP_KERNEL
);
852 pts_path
->mnt
= filp
->f_path
.mnt
;
853 pts_path
->dentry
= dentry
;
855 tty
->link
->driver_data
= pts_path
;
857 retval
= ptm_driver
->ops
->open(tty
, filp
);
861 tty_debug_hangup(tty
, "opening (count=%d)\n", tty
->count
);
870 // This will also put-ref the fsi
871 tty_release(inode
, filp
);
874 devpts_kill_index(fsi
, index
);
882 static struct file_operations ptmx_fops __ro_after_init
;
884 static void __init
unix98_pty_init(void)
886 ptm_driver
= tty_alloc_driver(NR_UNIX98_PTY_MAX
,
887 TTY_DRIVER_RESET_TERMIOS
|
888 TTY_DRIVER_REAL_RAW
|
889 TTY_DRIVER_DYNAMIC_DEV
|
890 TTY_DRIVER_DEVPTS_MEM
|
891 TTY_DRIVER_DYNAMIC_ALLOC
);
892 if (IS_ERR(ptm_driver
))
893 panic("Couldn't allocate Unix98 ptm driver");
894 pts_driver
= tty_alloc_driver(NR_UNIX98_PTY_MAX
,
895 TTY_DRIVER_RESET_TERMIOS
|
896 TTY_DRIVER_REAL_RAW
|
897 TTY_DRIVER_DYNAMIC_DEV
|
898 TTY_DRIVER_DEVPTS_MEM
|
899 TTY_DRIVER_DYNAMIC_ALLOC
);
900 if (IS_ERR(pts_driver
))
901 panic("Couldn't allocate Unix98 pts driver");
903 ptm_driver
->driver_name
= "pty_master";
904 ptm_driver
->name
= "ptm";
905 ptm_driver
->major
= UNIX98_PTY_MASTER_MAJOR
;
906 ptm_driver
->minor_start
= 0;
907 ptm_driver
->type
= TTY_DRIVER_TYPE_PTY
;
908 ptm_driver
->subtype
= PTY_TYPE_MASTER
;
909 ptm_driver
->init_termios
= tty_std_termios
;
910 ptm_driver
->init_termios
.c_iflag
= 0;
911 ptm_driver
->init_termios
.c_oflag
= 0;
912 ptm_driver
->init_termios
.c_cflag
= B38400
| CS8
| CREAD
;
913 ptm_driver
->init_termios
.c_lflag
= 0;
914 ptm_driver
->init_termios
.c_ispeed
= 38400;
915 ptm_driver
->init_termios
.c_ospeed
= 38400;
916 ptm_driver
->other
= pts_driver
;
917 tty_set_operations(ptm_driver
, &ptm_unix98_ops
);
919 pts_driver
->driver_name
= "pty_slave";
920 pts_driver
->name
= "pts";
921 pts_driver
->major
= UNIX98_PTY_SLAVE_MAJOR
;
922 pts_driver
->minor_start
= 0;
923 pts_driver
->type
= TTY_DRIVER_TYPE_PTY
;
924 pts_driver
->subtype
= PTY_TYPE_SLAVE
;
925 pts_driver
->init_termios
= tty_std_termios
;
926 pts_driver
->init_termios
.c_cflag
= B38400
| CS8
| CREAD
;
927 pts_driver
->init_termios
.c_ispeed
= 38400;
928 pts_driver
->init_termios
.c_ospeed
= 38400;
929 pts_driver
->other
= ptm_driver
;
930 tty_set_operations(pts_driver
, &pty_unix98_ops
);
932 if (tty_register_driver(ptm_driver
))
933 panic("Couldn't register Unix98 ptm driver");
934 if (tty_register_driver(pts_driver
))
935 panic("Couldn't register Unix98 pts driver");
937 /* Now create the /dev/ptmx special device */
938 tty_default_fops(&ptmx_fops
);
939 ptmx_fops
.open
= ptmx_open
;
941 cdev_init(&ptmx_cdev
, &ptmx_fops
);
942 if (cdev_add(&ptmx_cdev
, MKDEV(TTYAUX_MAJOR
, 2), 1) ||
943 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 2), 1, "/dev/ptmx") < 0)
944 panic("Couldn't register /dev/ptmx driver");
945 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 2), NULL
, "ptmx");
949 static inline void unix98_pty_init(void) { }
952 static int __init
pty_init(void)
958 device_initcall(pty_init
);