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.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>
28 #undef TTY_DEBUG_HANGUP
29 #ifdef TTY_DEBUG_HANGUP
30 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
32 # define tty_debug_hangup(tty, f, args...) do {} while (0)
35 #ifdef CONFIG_UNIX98_PTYS
36 static struct tty_driver
*ptm_driver
;
37 static struct tty_driver
*pts_driver
;
38 static DEFINE_MUTEX(devpts_mutex
);
41 static void pty_close(struct tty_struct
*tty
, struct file
*filp
)
44 if (tty
->driver
->subtype
== PTY_TYPE_MASTER
)
45 WARN_ON(tty
->count
> 1);
47 if (test_bit(TTY_IO_ERROR
, &tty
->flags
))
52 set_bit(TTY_IO_ERROR
, &tty
->flags
);
53 wake_up_interruptible(&tty
->read_wait
);
54 wake_up_interruptible(&tty
->write_wait
);
55 spin_lock_irq(&tty
->ctrl_lock
);
57 spin_unlock_irq(&tty
->ctrl_lock
);
58 /* Review - krefs on tty_link ?? */
61 set_bit(TTY_OTHER_CLOSED
, &tty
->link
->flags
);
62 tty_flip_buffer_push(tty
->link
->port
);
63 wake_up_interruptible(&tty
->link
->write_wait
);
64 if (tty
->driver
->subtype
== PTY_TYPE_MASTER
) {
65 set_bit(TTY_OTHER_CLOSED
, &tty
->flags
);
66 #ifdef CONFIG_UNIX98_PTYS
67 if (tty
->driver
== ptm_driver
) {
68 mutex_lock(&devpts_mutex
);
69 if (tty
->link
->driver_data
)
70 devpts_pty_kill(tty
->link
->driver_data
);
71 mutex_unlock(&devpts_mutex
);
74 tty_vhangup(tty
->link
);
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
82 * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
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.
88 static void pty_unthrottle(struct tty_struct
*tty
)
90 tty_wakeup(tty
->link
);
91 set_bit(TTY_THROTTLED
, &tty
->flags
);
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
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.
106 static int pty_write(struct tty_struct
*tty
, const unsigned char *buf
, int c
)
108 struct tty_struct
*to
= tty
->link
;
114 /* Stuff the data into the input queue of the other end */
115 c
= tty_insert_flip_string(to
->port
, buf
, c
);
118 tty_flip_buffer_push(to
->port
);
124 * pty_write_room - write space
125 * @tty: tty we are writing from
127 * Report how many bytes the ldisc can send into the queue for
131 static int pty_write_room(struct tty_struct
*tty
)
135 return tty_buffer_space_avail(tty
->link
->port
);
139 * pty_chars_in_buffer - characters currently in our tx queue
142 * Report how much we have in the transmit queue. As everything is
143 * instantly at the other end this is easy to implement.
146 static int pty_chars_in_buffer(struct tty_struct
*tty
)
151 /* Set the lock flag on a pty */
152 static int pty_set_lock(struct tty_struct
*tty
, int __user
*arg
)
155 if (get_user(val
, arg
))
158 set_bit(TTY_PTY_LOCK
, &tty
->flags
);
160 clear_bit(TTY_PTY_LOCK
, &tty
->flags
);
164 static int pty_get_lock(struct tty_struct
*tty
, int __user
*arg
)
166 int locked
= test_bit(TTY_PTY_LOCK
, &tty
->flags
);
167 return put_user(locked
, arg
);
170 /* Set the packet mode on a pty */
171 static int pty_set_pktmode(struct tty_struct
*tty
, int __user
*arg
)
175 if (get_user(pktmode
, arg
))
178 spin_lock_irq(&tty
->ctrl_lock
);
181 tty
->link
->ctrl_status
= 0;
187 spin_unlock_irq(&tty
->ctrl_lock
);
192 /* Get the packet mode of a pty */
193 static int pty_get_pktmode(struct tty_struct
*tty
, int __user
*arg
)
195 int pktmode
= tty
->packet
;
196 return put_user(pktmode
, arg
);
199 /* Send a signal to the slave */
200 static int pty_signal(struct tty_struct
*tty
, int sig
)
204 if (sig
!= SIGINT
&& sig
!= SIGQUIT
&& sig
!= SIGTSTP
)
208 pgrp
= tty_get_pgrp(tty
->link
);
210 kill_pgrp(pgrp
, sig
, 1);
216 static void pty_flush_buffer(struct tty_struct
*tty
)
218 struct tty_struct
*to
= tty
->link
;
219 struct tty_ldisc
*ld
;
224 ld
= tty_ldisc_ref(to
);
225 tty_buffer_flush(to
, ld
);
230 spin_lock_irq(&tty
->ctrl_lock
);
231 tty
->ctrl_status
|= TIOCPKT_FLUSHWRITE
;
232 wake_up_interruptible(&to
->read_wait
);
233 spin_unlock_irq(&tty
->ctrl_lock
);
237 static int pty_open(struct tty_struct
*tty
, struct file
*filp
)
239 if (!tty
|| !tty
->link
)
242 if (test_bit(TTY_OTHER_CLOSED
, &tty
->flags
))
244 if (test_bit(TTY_PTY_LOCK
, &tty
->link
->flags
))
246 if (tty
->driver
->subtype
== PTY_TYPE_SLAVE
&& tty
->link
->count
!= 1)
249 clear_bit(TTY_IO_ERROR
, &tty
->flags
);
250 /* TTY_OTHER_CLOSED must be cleared before TTY_OTHER_DONE */
251 clear_bit(TTY_OTHER_CLOSED
, &tty
->link
->flags
);
252 clear_bit(TTY_OTHER_DONE
, &tty
->link
->flags
);
253 set_bit(TTY_THROTTLED
, &tty
->flags
);
257 set_bit(TTY_IO_ERROR
, &tty
->flags
);
261 static void pty_set_termios(struct tty_struct
*tty
,
262 struct ktermios
*old_termios
)
264 /* See if packet mode change of state. */
265 if (tty
->link
&& tty
->link
->packet
) {
266 int extproc
= (old_termios
->c_lflag
& EXTPROC
) |
267 (tty
->termios
.c_lflag
& EXTPROC
);
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 retval
= tty_init_termios(tty
);
413 retval
= tty_init_termios(o_tty
);
415 goto err_free_termios
;
417 driver
->other
->ttys
[idx
] = o_tty
;
418 driver
->ttys
[idx
] = tty
;
420 memset(&tty
->termios_locked
, 0, sizeof(tty
->termios_locked
));
421 tty
->termios
= driver
->init_termios
;
422 memset(&o_tty
->termios_locked
, 0, sizeof(tty
->termios_locked
));
423 o_tty
->termios
= driver
->other
->init_termios
;
427 * Everything allocated ... set up the o_tty structure.
429 tty_driver_kref_get(driver
->other
);
430 /* Establish the links in both directions */
433 tty_port_init(ports
[0]);
434 tty_port_init(ports
[1]);
435 tty_buffer_set_limit(ports
[0], 8192);
436 tty_buffer_set_limit(ports
[1], 8192);
437 o_tty
->port
= ports
[0];
438 tty
->port
= ports
[1];
439 o_tty
->port
->itty
= o_tty
;
441 tty_buffer_set_lock_subclass(o_tty
->port
);
443 tty_driver_kref_get(driver
);
449 tty_free_termios(tty
);
451 deinitialize_tty_struct(o_tty
);
452 free_tty_struct(o_tty
);
454 module_put(driver
->other
->owner
);
461 static void pty_cleanup(struct tty_struct
*tty
)
463 tty_port_put(tty
->port
);
466 /* Traditional BSD devices */
467 #ifdef CONFIG_LEGACY_PTYS
469 static int pty_install(struct tty_driver
*driver
, struct tty_struct
*tty
)
471 return pty_common_install(driver
, tty
, true);
474 static void pty_remove(struct tty_driver
*driver
, struct tty_struct
*tty
)
476 struct tty_struct
*pair
= tty
->link
;
477 driver
->ttys
[tty
->index
] = NULL
;
479 pair
->driver
->ttys
[pair
->index
] = NULL
;
482 static int pty_bsd_ioctl(struct tty_struct
*tty
,
483 unsigned int cmd
, unsigned long arg
)
486 case TIOCSPTLCK
: /* Set PT Lock (disallow slave open) */
487 return pty_set_lock(tty
, (int __user
*) arg
);
488 case TIOCGPTLCK
: /* Get PT Lock status */
489 return pty_get_lock(tty
, (int __user
*)arg
);
490 case TIOCPKT
: /* Set PT packet mode */
491 return pty_set_pktmode(tty
, (int __user
*)arg
);
492 case TIOCGPKT
: /* Get PT packet mode */
493 return pty_get_pktmode(tty
, (int __user
*)arg
);
494 case TIOCSIG
: /* Send signal to other side of pty */
495 return pty_signal(tty
, (int) arg
);
496 case TIOCGPTN
: /* TTY returns ENOTTY, but glibc expects EINVAL here */
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 .cleanup
= pty_cleanup
,
524 .resize
= pty_resize
,
528 static const struct tty_operations slave_pty_ops_bsd
= {
529 .install
= pty_install
,
533 .write_room
= pty_write_room
,
534 .flush_buffer
= pty_flush_buffer
,
535 .chars_in_buffer
= pty_chars_in_buffer
,
536 .unthrottle
= pty_unthrottle
,
537 .set_termios
= pty_set_termios
,
538 .cleanup
= pty_cleanup
,
539 .resize
= pty_resize
,
545 static void __init
legacy_pty_init(void)
547 struct tty_driver
*pty_driver
, *pty_slave_driver
;
549 if (legacy_count
<= 0)
552 pty_driver
= tty_alloc_driver(legacy_count
,
553 TTY_DRIVER_RESET_TERMIOS
|
554 TTY_DRIVER_REAL_RAW
|
555 TTY_DRIVER_DYNAMIC_ALLOC
);
556 if (IS_ERR(pty_driver
))
557 panic("Couldn't allocate pty driver");
559 pty_slave_driver
= tty_alloc_driver(legacy_count
,
560 TTY_DRIVER_RESET_TERMIOS
|
561 TTY_DRIVER_REAL_RAW
|
562 TTY_DRIVER_DYNAMIC_ALLOC
);
563 if (IS_ERR(pty_slave_driver
))
564 panic("Couldn't allocate pty slave driver");
566 pty_driver
->driver_name
= "pty_master";
567 pty_driver
->name
= "pty";
568 pty_driver
->major
= PTY_MASTER_MAJOR
;
569 pty_driver
->minor_start
= 0;
570 pty_driver
->type
= TTY_DRIVER_TYPE_PTY
;
571 pty_driver
->subtype
= PTY_TYPE_MASTER
;
572 pty_driver
->init_termios
= tty_std_termios
;
573 pty_driver
->init_termios
.c_iflag
= 0;
574 pty_driver
->init_termios
.c_oflag
= 0;
575 pty_driver
->init_termios
.c_cflag
= B38400
| CS8
| CREAD
;
576 pty_driver
->init_termios
.c_lflag
= 0;
577 pty_driver
->init_termios
.c_ispeed
= 38400;
578 pty_driver
->init_termios
.c_ospeed
= 38400;
579 pty_driver
->other
= pty_slave_driver
;
580 tty_set_operations(pty_driver
, &master_pty_ops_bsd
);
582 pty_slave_driver
->driver_name
= "pty_slave";
583 pty_slave_driver
->name
= "ttyp";
584 pty_slave_driver
->major
= PTY_SLAVE_MAJOR
;
585 pty_slave_driver
->minor_start
= 0;
586 pty_slave_driver
->type
= TTY_DRIVER_TYPE_PTY
;
587 pty_slave_driver
->subtype
= PTY_TYPE_SLAVE
;
588 pty_slave_driver
->init_termios
= tty_std_termios
;
589 pty_slave_driver
->init_termios
.c_cflag
= B38400
| CS8
| CREAD
;
590 pty_slave_driver
->init_termios
.c_ispeed
= 38400;
591 pty_slave_driver
->init_termios
.c_ospeed
= 38400;
592 pty_slave_driver
->other
= pty_driver
;
593 tty_set_operations(pty_slave_driver
, &slave_pty_ops_bsd
);
595 if (tty_register_driver(pty_driver
))
596 panic("Couldn't register pty driver");
597 if (tty_register_driver(pty_slave_driver
))
598 panic("Couldn't register pty slave driver");
601 static inline void legacy_pty_init(void) { }
605 #ifdef CONFIG_UNIX98_PTYS
607 static struct cdev ptmx_cdev
;
609 static int pty_unix98_ioctl(struct tty_struct
*tty
,
610 unsigned int cmd
, unsigned long arg
)
613 case TIOCSPTLCK
: /* Set PT Lock (disallow slave open) */
614 return pty_set_lock(tty
, (int __user
*)arg
);
615 case TIOCGPTLCK
: /* Get PT Lock status */
616 return pty_get_lock(tty
, (int __user
*)arg
);
617 case TIOCPKT
: /* Set PT packet mode */
618 return pty_set_pktmode(tty
, (int __user
*)arg
);
619 case TIOCGPKT
: /* Get PT packet mode */
620 return pty_get_pktmode(tty
, (int __user
*)arg
);
621 case TIOCGPTN
: /* Get PT Number */
622 return put_user(tty
->index
, (unsigned int __user
*)arg
);
623 case TIOCSIG
: /* Send signal to other side of pty */
624 return pty_signal(tty
, (int) arg
);
631 * ptm_unix98_lookup - find a pty master
632 * @driver: ptm driver
635 * Look up a pty master device. Called under the tty_mutex for now.
636 * This provides our locking.
639 static struct tty_struct
*ptm_unix98_lookup(struct tty_driver
*driver
,
640 struct inode
*ptm_inode
, int idx
)
642 /* Master must be open via /dev/ptmx */
643 return ERR_PTR(-EIO
);
647 * pts_unix98_lookup - find a pty slave
648 * @driver: pts driver
651 * Look up a pty master device. Called under the tty_mutex for now.
652 * This provides our locking for the tty pointer.
655 static struct tty_struct
*pts_unix98_lookup(struct tty_driver
*driver
,
656 struct inode
*pts_inode
, int idx
)
658 struct tty_struct
*tty
;
660 mutex_lock(&devpts_mutex
);
661 tty
= devpts_get_priv(pts_inode
);
662 mutex_unlock(&devpts_mutex
);
663 /* Master must be open before slave */
665 return ERR_PTR(-EIO
);
669 /* We have no need to install and remove our tty objects as devpts does all
672 static int pty_unix98_install(struct tty_driver
*driver
, struct tty_struct
*tty
)
674 return pty_common_install(driver
, tty
, false);
677 static void pty_unix98_remove(struct tty_driver
*driver
, struct tty_struct
*tty
)
681 /* this is called once with whichever end is closed last */
682 static void pty_unix98_shutdown(struct tty_struct
*tty
)
684 struct inode
*ptmx_inode
;
686 if (tty
->driver
->subtype
== PTY_TYPE_MASTER
)
687 ptmx_inode
= tty
->driver_data
;
689 ptmx_inode
= tty
->link
->driver_data
;
690 devpts_kill_index(ptmx_inode
, tty
->index
);
691 devpts_del_ref(ptmx_inode
);
694 static const struct tty_operations ptm_unix98_ops
= {
695 .lookup
= ptm_unix98_lookup
,
696 .install
= pty_unix98_install
,
697 .remove
= pty_unix98_remove
,
701 .write_room
= pty_write_room
,
702 .flush_buffer
= pty_flush_buffer
,
703 .chars_in_buffer
= pty_chars_in_buffer
,
704 .unthrottle
= pty_unthrottle
,
705 .ioctl
= pty_unix98_ioctl
,
706 .resize
= pty_resize
,
707 .shutdown
= pty_unix98_shutdown
,
708 .cleanup
= pty_cleanup
711 static const struct tty_operations pty_unix98_ops
= {
712 .lookup
= pts_unix98_lookup
,
713 .install
= pty_unix98_install
,
714 .remove
= pty_unix98_remove
,
718 .write_room
= pty_write_room
,
719 .flush_buffer
= pty_flush_buffer
,
720 .chars_in_buffer
= pty_chars_in_buffer
,
721 .unthrottle
= pty_unthrottle
,
722 .set_termios
= pty_set_termios
,
725 .shutdown
= pty_unix98_shutdown
,
726 .cleanup
= pty_cleanup
,
730 * ptmx_open - open a unix 98 pty master
731 * @inode: inode of device file
732 * @filp: file pointer to tty
734 * Allocate a unix98 pty master device from the ptmx driver.
736 * Locking: tty_mutex protects the init_dev work. tty->count should
738 * allocated_ptys_lock handles the list of free pty numbers
741 static int ptmx_open(struct inode
*inode
, struct file
*filp
)
743 struct tty_struct
*tty
;
744 struct inode
*slave_inode
;
748 nonseekable_open(inode
, filp
);
750 /* We refuse fsnotify events on ptmx, since it's a shared resource */
751 filp
->f_mode
|= FMODE_NONOTIFY
;
753 retval
= tty_alloc_file(filp
);
757 /* find a device that is not in use. */
758 mutex_lock(&devpts_mutex
);
759 index
= devpts_new_index(inode
);
762 mutex_unlock(&devpts_mutex
);
766 mutex_unlock(&devpts_mutex
);
768 mutex_lock(&tty_mutex
);
769 tty
= tty_init_dev(ptm_driver
, index
);
772 retval
= PTR_ERR(tty
);
776 /* The tty returned here is locked so we can safely
778 mutex_unlock(&tty_mutex
);
780 set_bit(TTY_PTY_LOCK
, &tty
->flags
); /* LOCK THE SLAVE */
781 tty
->driver_data
= inode
;
784 * In the case where all references to ptmx inode are dropped and we
785 * still have /dev/tty opened pointing to the master/slave pair (ptmx
786 * is closed/released before /dev/tty), we must make sure that the inode
787 * is still valid when we call the final pty_unix98_shutdown, thus we
788 * hold an additional reference to the ptmx inode. For the same /dev/tty
789 * last close case, we also need to make sure the super_block isn't
790 * destroyed (devpts instance unmounted), before /dev/tty is closed and
791 * on its release devpts_kill_index is called.
793 devpts_add_ref(inode
);
795 tty_add_file(tty
, filp
);
797 slave_inode
= devpts_pty_new(inode
,
798 MKDEV(UNIX98_PTY_SLAVE_MAJOR
, index
), index
,
800 if (IS_ERR(slave_inode
)) {
801 retval
= PTR_ERR(slave_inode
);
804 tty
->link
->driver_data
= slave_inode
;
806 retval
= ptm_driver
->ops
->open(tty
, filp
);
810 tty_debug_hangup(tty
, "opening (count=%d)\n", tty
->count
);
816 tty_release(inode
, filp
);
819 mutex_unlock(&tty_mutex
);
820 devpts_kill_index(inode
, index
);
826 static struct file_operations ptmx_fops
;
828 static void __init
unix98_pty_init(void)
830 ptm_driver
= tty_alloc_driver(NR_UNIX98_PTY_MAX
,
831 TTY_DRIVER_RESET_TERMIOS
|
832 TTY_DRIVER_REAL_RAW
|
833 TTY_DRIVER_DYNAMIC_DEV
|
834 TTY_DRIVER_DEVPTS_MEM
|
835 TTY_DRIVER_DYNAMIC_ALLOC
);
836 if (IS_ERR(ptm_driver
))
837 panic("Couldn't allocate Unix98 ptm driver");
838 pts_driver
= tty_alloc_driver(NR_UNIX98_PTY_MAX
,
839 TTY_DRIVER_RESET_TERMIOS
|
840 TTY_DRIVER_REAL_RAW
|
841 TTY_DRIVER_DYNAMIC_DEV
|
842 TTY_DRIVER_DEVPTS_MEM
|
843 TTY_DRIVER_DYNAMIC_ALLOC
);
844 if (IS_ERR(pts_driver
))
845 panic("Couldn't allocate Unix98 pts driver");
847 ptm_driver
->driver_name
= "pty_master";
848 ptm_driver
->name
= "ptm";
849 ptm_driver
->major
= UNIX98_PTY_MASTER_MAJOR
;
850 ptm_driver
->minor_start
= 0;
851 ptm_driver
->type
= TTY_DRIVER_TYPE_PTY
;
852 ptm_driver
->subtype
= PTY_TYPE_MASTER
;
853 ptm_driver
->init_termios
= tty_std_termios
;
854 ptm_driver
->init_termios
.c_iflag
= 0;
855 ptm_driver
->init_termios
.c_oflag
= 0;
856 ptm_driver
->init_termios
.c_cflag
= B38400
| CS8
| CREAD
;
857 ptm_driver
->init_termios
.c_lflag
= 0;
858 ptm_driver
->init_termios
.c_ispeed
= 38400;
859 ptm_driver
->init_termios
.c_ospeed
= 38400;
860 ptm_driver
->other
= pts_driver
;
861 tty_set_operations(ptm_driver
, &ptm_unix98_ops
);
863 pts_driver
->driver_name
= "pty_slave";
864 pts_driver
->name
= "pts";
865 pts_driver
->major
= UNIX98_PTY_SLAVE_MAJOR
;
866 pts_driver
->minor_start
= 0;
867 pts_driver
->type
= TTY_DRIVER_TYPE_PTY
;
868 pts_driver
->subtype
= PTY_TYPE_SLAVE
;
869 pts_driver
->init_termios
= tty_std_termios
;
870 pts_driver
->init_termios
.c_cflag
= B38400
| CS8
| CREAD
;
871 pts_driver
->init_termios
.c_ispeed
= 38400;
872 pts_driver
->init_termios
.c_ospeed
= 38400;
873 pts_driver
->other
= ptm_driver
;
874 tty_set_operations(pts_driver
, &pty_unix98_ops
);
876 if (tty_register_driver(ptm_driver
))
877 panic("Couldn't register Unix98 ptm driver");
878 if (tty_register_driver(pts_driver
))
879 panic("Couldn't register Unix98 pts driver");
881 /* Now create the /dev/ptmx special device */
882 tty_default_fops(&ptmx_fops
);
883 ptmx_fops
.open
= ptmx_open
;
885 cdev_init(&ptmx_cdev
, &ptmx_fops
);
886 if (cdev_add(&ptmx_cdev
, MKDEV(TTYAUX_MAJOR
, 2), 1) ||
887 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 2), 1, "/dev/ptmx") < 0)
888 panic("Couldn't register /dev/ptmx driver");
889 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 2), NULL
, "ptmx");
893 static inline void unix98_pty_init(void) { }
896 static int __init
pty_init(void)
902 device_initcall(pty_init
);