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
7 * When reading this code see also fs/devpts. In particular note that the
8 * driver_data field is used by the devpts side as a binding to the devpts
12 #include <linux/module.h>
14 #include <linux/errno.h>
15 #include <linux/interrupt.h>
16 #include <linux/tty.h>
17 #include <linux/tty_flip.h>
18 #include <linux/fcntl.h>
19 #include <linux/sched.h>
20 #include <linux/string.h>
21 #include <linux/major.h>
23 #include <linux/init.h>
24 #include <linux/device.h>
25 #include <linux/uaccess.h>
26 #include <linux/bitops.h>
27 #include <linux/devpts_fs.h>
28 #include <linux/slab.h>
29 #include <linux/mutex.h>
32 #ifdef CONFIG_UNIX98_PTYS
33 static struct tty_driver
*ptm_driver
;
34 static struct tty_driver
*pts_driver
;
35 static DEFINE_MUTEX(devpts_mutex
);
38 static void pty_close(struct tty_struct
*tty
, struct file
*filp
)
41 if (tty
->driver
->subtype
== PTY_TYPE_MASTER
)
42 WARN_ON(tty
->count
> 1);
47 wake_up_interruptible(&tty
->read_wait
);
48 wake_up_interruptible(&tty
->write_wait
);
50 /* Review - krefs on tty_link ?? */
53 tty
->link
->packet
= 0;
54 set_bit(TTY_OTHER_CLOSED
, &tty
->link
->flags
);
55 wake_up_interruptible(&tty
->link
->read_wait
);
56 wake_up_interruptible(&tty
->link
->write_wait
);
57 if (tty
->driver
->subtype
== PTY_TYPE_MASTER
) {
58 set_bit(TTY_OTHER_CLOSED
, &tty
->flags
);
59 #ifdef CONFIG_UNIX98_PTYS
60 if (tty
->driver
== ptm_driver
) {
61 mutex_lock(&devpts_mutex
);
62 devpts_pty_kill(tty
->link
);
63 mutex_unlock(&devpts_mutex
);
67 tty_vhangup(tty
->link
);
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.
82 static void pty_unthrottle(struct tty_struct
*tty
)
84 tty_wakeup(tty
->link
);
85 set_bit(TTY_THROTTLED
, &tty
->flags
);
89 * pty_space - report space left for writing
90 * @to: tty we are writing into
92 * The tty buffers allow 64K but we sneak a peak and clip at 8K this
93 * allows a lot of overspill room for echo and other fun messes to
97 static int pty_space(struct tty_struct
*to
)
99 int n
= 8192 - to
->buf
.memory_used
;
106 * pty_write - write to a pty
107 * @tty: the tty we write from
108 * @buf: kernel buffer of data
109 * @count: bytes to write
111 * Our "hardware" write method. Data is coming from the ldisc which
112 * may be in a non sleeping state. We simply throw this at the other
113 * end of the link as if we were an IRQ handler receiving stuff for
114 * the other side of the pty/tty pair.
117 static int pty_write(struct tty_struct
*tty
, const unsigned char *buf
, int c
)
119 struct tty_struct
*to
= tty
->link
;
125 /* Stuff the data into the input queue of the other end */
126 c
= tty_insert_flip_string(to
, buf
, c
);
129 tty_flip_buffer_push(to
);
137 * pty_write_room - write space
138 * @tty: tty we are writing from
140 * Report how many bytes the ldisc can send into the queue for
144 static int pty_write_room(struct tty_struct
*tty
)
148 return pty_space(tty
->link
);
152 * pty_chars_in_buffer - characters currently in our tx queue
155 * Report how much we have in the transmit queue. As everything is
156 * instantly at the other end this is easy to implement.
159 static int pty_chars_in_buffer(struct tty_struct
*tty
)
164 /* Set the lock flag on a pty */
165 static int pty_set_lock(struct tty_struct
*tty
, int __user
*arg
)
168 if (get_user(val
, arg
))
171 set_bit(TTY_PTY_LOCK
, &tty
->flags
);
173 clear_bit(TTY_PTY_LOCK
, &tty
->flags
);
177 /* Send a signal to the slave */
178 static int pty_signal(struct tty_struct
*tty
, int sig
)
184 spin_lock_irqsave(&tty
->link
->ctrl_lock
, flags
);
185 pgrp
= get_pid(tty
->link
->pgrp
);
186 spin_unlock_irqrestore(&tty
->link
->ctrl_lock
, flags
);
188 kill_pgrp(pgrp
, sig
, 1);
194 static void pty_flush_buffer(struct tty_struct
*tty
)
196 struct tty_struct
*to
= tty
->link
;
201 /* tty_buffer_flush(to); FIXME */
203 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
204 tty
->ctrl_status
|= TIOCPKT_FLUSHWRITE
;
205 wake_up_interruptible(&to
->read_wait
);
206 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
210 static int pty_open(struct tty_struct
*tty
, struct file
*filp
)
212 int retval
= -ENODEV
;
214 if (!tty
|| !tty
->link
)
218 if (test_bit(TTY_OTHER_CLOSED
, &tty
->flags
))
220 if (test_bit(TTY_PTY_LOCK
, &tty
->link
->flags
))
222 if (tty
->link
->count
!= 1)
225 clear_bit(TTY_OTHER_CLOSED
, &tty
->link
->flags
);
226 set_bit(TTY_THROTTLED
, &tty
->flags
);
232 static void pty_set_termios(struct tty_struct
*tty
,
233 struct ktermios
*old_termios
)
235 tty
->termios
.c_cflag
&= ~(CSIZE
| PARENB
);
236 tty
->termios
.c_cflag
|= (CS8
| CREAD
);
240 * pty_do_resize - resize event
241 * @tty: tty being resized
242 * @ws: window size being set.
244 * Update the termios variables and send the necessary signals to
245 * peform a terminal resize correctly
248 int pty_resize(struct tty_struct
*tty
, struct winsize
*ws
)
250 struct pid
*pgrp
, *rpgrp
;
252 struct tty_struct
*pty
= tty
->link
;
254 /* For a PTY we need to lock the tty side */
255 mutex_lock(&tty
->termios_mutex
);
256 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
259 /* Get the PID values and reference them so we can
260 avoid holding the tty ctrl lock while sending signals.
261 We need to lock these individually however. */
263 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
264 pgrp
= get_pid(tty
->pgrp
);
265 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
267 spin_lock_irqsave(&pty
->ctrl_lock
, flags
);
268 rpgrp
= get_pid(pty
->pgrp
);
269 spin_unlock_irqrestore(&pty
->ctrl_lock
, flags
);
272 kill_pgrp(pgrp
, SIGWINCH
, 1);
273 if (rpgrp
!= pgrp
&& rpgrp
)
274 kill_pgrp(rpgrp
, SIGWINCH
, 1);
280 pty
->winsize
= *ws
; /* Never used so will go away soon */
282 mutex_unlock(&tty
->termios_mutex
);
287 * pty_common_install - set up the pty pair
288 * @driver: the pty driver
289 * @tty: the tty being instantiated
290 * @bool: legacy, true if this is BSD style
292 * Perform the initial set up for the tty/pty pair. Called from the
293 * tty layer when the port is first opened.
295 * Locking: the caller must hold the tty_mutex
297 static int pty_common_install(struct tty_driver
*driver
, struct tty_struct
*tty
,
300 struct tty_struct
*o_tty
;
301 struct tty_port
*ports
[2];
302 int idx
= tty
->index
;
303 int retval
= -ENOMEM
;
305 o_tty
= alloc_tty_struct();
308 ports
[0] = kmalloc(sizeof **ports
, GFP_KERNEL
);
309 ports
[1] = kmalloc(sizeof **ports
, GFP_KERNEL
);
310 if (!ports
[0] || !ports
[1])
312 if (!try_module_get(driver
->other
->owner
)) {
313 /* This cannot in fact currently happen */
316 initialize_tty_struct(o_tty
, driver
->other
, idx
);
319 /* We always use new tty termios data so we can do this
321 retval
= tty_init_termios(tty
);
325 retval
= tty_init_termios(o_tty
);
327 goto err_free_termios
;
329 driver
->other
->ttys
[idx
] = o_tty
;
330 driver
->ttys
[idx
] = tty
;
332 memset(&tty
->termios_locked
, 0, sizeof(tty
->termios_locked
));
333 tty
->termios
= driver
->init_termios
;
334 memset(&o_tty
->termios_locked
, 0, sizeof(tty
->termios_locked
));
335 o_tty
->termios
= driver
->other
->init_termios
;
339 * Everything allocated ... set up the o_tty structure.
341 tty_driver_kref_get(driver
->other
);
342 if (driver
->subtype
== PTY_TYPE_MASTER
)
344 /* Establish the links in both directions */
347 tty_port_init(ports
[0]);
348 tty_port_init(ports
[1]);
349 o_tty
->port
= ports
[0];
350 tty
->port
= ports
[1];
352 tty_driver_kref_get(driver
);
357 tty_free_termios(tty
);
359 deinitialize_tty_struct(o_tty
);
360 module_put(o_tty
->driver
->owner
);
364 free_tty_struct(o_tty
);
369 static void pty_cleanup(struct tty_struct
*tty
)
374 /* Traditional BSD devices */
375 #ifdef CONFIG_LEGACY_PTYS
377 static int pty_install(struct tty_driver
*driver
, struct tty_struct
*tty
)
379 return pty_common_install(driver
, tty
, true);
382 static void pty_remove(struct tty_driver
*driver
, struct tty_struct
*tty
)
384 struct tty_struct
*pair
= tty
->link
;
385 driver
->ttys
[tty
->index
] = NULL
;
387 pair
->driver
->ttys
[pair
->index
] = NULL
;
390 static int pty_bsd_ioctl(struct tty_struct
*tty
,
391 unsigned int cmd
, unsigned long arg
)
394 case TIOCSPTLCK
: /* Set PT Lock (disallow slave open) */
395 return pty_set_lock(tty
, (int __user
*) arg
);
396 case TIOCSIG
: /* Send signal to other side of pty */
397 return pty_signal(tty
, (int) arg
);
402 static int legacy_count
= CONFIG_LEGACY_PTY_COUNT
;
403 module_param(legacy_count
, int, 0);
406 * The master side of a pty can do TIOCSPTLCK and thus
409 static const struct tty_operations master_pty_ops_bsd
= {
410 .install
= pty_install
,
414 .write_room
= pty_write_room
,
415 .flush_buffer
= pty_flush_buffer
,
416 .chars_in_buffer
= pty_chars_in_buffer
,
417 .unthrottle
= pty_unthrottle
,
418 .set_termios
= pty_set_termios
,
419 .ioctl
= pty_bsd_ioctl
,
420 .cleanup
= pty_cleanup
,
421 .resize
= pty_resize
,
425 static const struct tty_operations slave_pty_ops_bsd
= {
426 .install
= pty_install
,
430 .write_room
= pty_write_room
,
431 .flush_buffer
= pty_flush_buffer
,
432 .chars_in_buffer
= pty_chars_in_buffer
,
433 .unthrottle
= pty_unthrottle
,
434 .set_termios
= pty_set_termios
,
435 .cleanup
= pty_cleanup
,
436 .resize
= pty_resize
,
440 static void __init
legacy_pty_init(void)
442 struct tty_driver
*pty_driver
, *pty_slave_driver
;
444 if (legacy_count
<= 0)
447 pty_driver
= alloc_tty_driver(legacy_count
);
449 panic("Couldn't allocate pty driver");
451 pty_slave_driver
= alloc_tty_driver(legacy_count
);
452 if (!pty_slave_driver
)
453 panic("Couldn't allocate pty slave driver");
455 pty_driver
->driver_name
= "pty_master";
456 pty_driver
->name
= "pty";
457 pty_driver
->major
= PTY_MASTER_MAJOR
;
458 pty_driver
->minor_start
= 0;
459 pty_driver
->type
= TTY_DRIVER_TYPE_PTY
;
460 pty_driver
->subtype
= PTY_TYPE_MASTER
;
461 pty_driver
->init_termios
= tty_std_termios
;
462 pty_driver
->init_termios
.c_iflag
= 0;
463 pty_driver
->init_termios
.c_oflag
= 0;
464 pty_driver
->init_termios
.c_cflag
= B38400
| CS8
| CREAD
;
465 pty_driver
->init_termios
.c_lflag
= 0;
466 pty_driver
->init_termios
.c_ispeed
= 38400;
467 pty_driver
->init_termios
.c_ospeed
= 38400;
468 pty_driver
->flags
= TTY_DRIVER_RESET_TERMIOS
| TTY_DRIVER_REAL_RAW
;
469 pty_driver
->other
= pty_slave_driver
;
470 tty_set_operations(pty_driver
, &master_pty_ops_bsd
);
472 pty_slave_driver
->driver_name
= "pty_slave";
473 pty_slave_driver
->name
= "ttyp";
474 pty_slave_driver
->major
= PTY_SLAVE_MAJOR
;
475 pty_slave_driver
->minor_start
= 0;
476 pty_slave_driver
->type
= TTY_DRIVER_TYPE_PTY
;
477 pty_slave_driver
->subtype
= PTY_TYPE_SLAVE
;
478 pty_slave_driver
->init_termios
= tty_std_termios
;
479 pty_slave_driver
->init_termios
.c_cflag
= B38400
| CS8
| CREAD
;
480 pty_slave_driver
->init_termios
.c_ispeed
= 38400;
481 pty_slave_driver
->init_termios
.c_ospeed
= 38400;
482 pty_slave_driver
->flags
= TTY_DRIVER_RESET_TERMIOS
|
484 pty_slave_driver
->other
= pty_driver
;
485 tty_set_operations(pty_slave_driver
, &slave_pty_ops_bsd
);
487 if (tty_register_driver(pty_driver
))
488 panic("Couldn't register pty driver");
489 if (tty_register_driver(pty_slave_driver
))
490 panic("Couldn't register pty slave driver");
493 static inline void legacy_pty_init(void) { }
497 #ifdef CONFIG_UNIX98_PTYS
499 static struct cdev ptmx_cdev
;
501 static int pty_unix98_ioctl(struct tty_struct
*tty
,
502 unsigned int cmd
, unsigned long arg
)
505 case TIOCSPTLCK
: /* Set PT Lock (disallow slave open) */
506 return pty_set_lock(tty
, (int __user
*)arg
);
507 case TIOCGPTN
: /* Get PT Number */
508 return put_user(tty
->index
, (unsigned int __user
*)arg
);
509 case TIOCSIG
: /* Send signal to other side of pty */
510 return pty_signal(tty
, (int) arg
);
517 * ptm_unix98_lookup - find a pty master
518 * @driver: ptm driver
521 * Look up a pty master device. Called under the tty_mutex for now.
522 * This provides our locking.
525 static struct tty_struct
*ptm_unix98_lookup(struct tty_driver
*driver
,
526 struct inode
*ptm_inode
, int idx
)
528 /* Master must be open via /dev/ptmx */
529 return ERR_PTR(-EIO
);
533 * pts_unix98_lookup - find a pty slave
534 * @driver: pts driver
537 * Look up a pty master device. Called under the tty_mutex for now.
538 * This provides our locking for the tty pointer.
541 static struct tty_struct
*pts_unix98_lookup(struct tty_driver
*driver
,
542 struct inode
*pts_inode
, int idx
)
544 struct tty_struct
*tty
;
546 mutex_lock(&devpts_mutex
);
547 tty
= devpts_get_tty(pts_inode
, idx
);
548 mutex_unlock(&devpts_mutex
);
549 /* Master must be open before slave */
551 return ERR_PTR(-EIO
);
555 /* We have no need to install and remove our tty objects as devpts does all
558 static int pty_unix98_install(struct tty_driver
*driver
, struct tty_struct
*tty
)
560 return pty_common_install(driver
, tty
, false);
563 static void pty_unix98_remove(struct tty_driver
*driver
, struct tty_struct
*tty
)
567 static const struct tty_operations ptm_unix98_ops
= {
568 .lookup
= ptm_unix98_lookup
,
569 .install
= pty_unix98_install
,
570 .remove
= pty_unix98_remove
,
574 .write_room
= pty_write_room
,
575 .flush_buffer
= pty_flush_buffer
,
576 .chars_in_buffer
= pty_chars_in_buffer
,
577 .unthrottle
= pty_unthrottle
,
578 .set_termios
= pty_set_termios
,
579 .ioctl
= pty_unix98_ioctl
,
580 .resize
= pty_resize
,
581 .cleanup
= pty_cleanup
584 static const struct tty_operations pty_unix98_ops
= {
585 .lookup
= pts_unix98_lookup
,
586 .install
= pty_unix98_install
,
587 .remove
= pty_unix98_remove
,
591 .write_room
= pty_write_room
,
592 .flush_buffer
= pty_flush_buffer
,
593 .chars_in_buffer
= pty_chars_in_buffer
,
594 .unthrottle
= pty_unthrottle
,
595 .set_termios
= pty_set_termios
,
596 .cleanup
= pty_cleanup
,
600 * ptmx_open - open a unix 98 pty master
601 * @inode: inode of device file
602 * @filp: file pointer to tty
604 * Allocate a unix98 pty master device from the ptmx driver.
606 * Locking: tty_mutex protects the init_dev work. tty->count should
608 * allocated_ptys_lock handles the list of free pty numbers
611 static int ptmx_open(struct inode
*inode
, struct file
*filp
)
613 struct tty_struct
*tty
;
617 nonseekable_open(inode
, filp
);
619 retval
= tty_alloc_file(filp
);
623 /* find a device that is not in use. */
624 mutex_lock(&devpts_mutex
);
625 index
= devpts_new_index(inode
);
631 mutex_unlock(&devpts_mutex
);
633 mutex_lock(&tty_mutex
);
634 tty
= tty_init_dev(ptm_driver
, index
);
637 retval
= PTR_ERR(tty
);
641 /* The tty returned here is locked so we can safely
643 mutex_unlock(&tty_mutex
);
645 set_bit(TTY_PTY_LOCK
, &tty
->flags
); /* LOCK THE SLAVE */
647 tty_add_file(tty
, filp
);
649 retval
= devpts_pty_new(inode
, tty
->link
);
653 retval
= ptm_driver
->ops
->open(tty
, filp
);
661 tty_release(inode
, filp
);
664 mutex_unlock(&tty_mutex
);
665 devpts_kill_index(inode
, index
);
667 mutex_unlock(&devpts_mutex
);
672 static struct file_operations ptmx_fops
;
674 static void __init
unix98_pty_init(void)
676 ptm_driver
= alloc_tty_driver(NR_UNIX98_PTY_MAX
);
678 panic("Couldn't allocate Unix98 ptm driver");
679 pts_driver
= alloc_tty_driver(NR_UNIX98_PTY_MAX
);
681 panic("Couldn't allocate Unix98 pts driver");
683 ptm_driver
->driver_name
= "pty_master";
684 ptm_driver
->name
= "ptm";
685 ptm_driver
->major
= UNIX98_PTY_MASTER_MAJOR
;
686 ptm_driver
->minor_start
= 0;
687 ptm_driver
->type
= TTY_DRIVER_TYPE_PTY
;
688 ptm_driver
->subtype
= PTY_TYPE_MASTER
;
689 ptm_driver
->init_termios
= tty_std_termios
;
690 ptm_driver
->init_termios
.c_iflag
= 0;
691 ptm_driver
->init_termios
.c_oflag
= 0;
692 ptm_driver
->init_termios
.c_cflag
= B38400
| CS8
| CREAD
;
693 ptm_driver
->init_termios
.c_lflag
= 0;
694 ptm_driver
->init_termios
.c_ispeed
= 38400;
695 ptm_driver
->init_termios
.c_ospeed
= 38400;
696 ptm_driver
->flags
= TTY_DRIVER_RESET_TERMIOS
| TTY_DRIVER_REAL_RAW
|
697 TTY_DRIVER_DYNAMIC_DEV
| TTY_DRIVER_DEVPTS_MEM
;
698 ptm_driver
->other
= pts_driver
;
699 tty_set_operations(ptm_driver
, &ptm_unix98_ops
);
701 pts_driver
->driver_name
= "pty_slave";
702 pts_driver
->name
= "pts";
703 pts_driver
->major
= UNIX98_PTY_SLAVE_MAJOR
;
704 pts_driver
->minor_start
= 0;
705 pts_driver
->type
= TTY_DRIVER_TYPE_PTY
;
706 pts_driver
->subtype
= PTY_TYPE_SLAVE
;
707 pts_driver
->init_termios
= tty_std_termios
;
708 pts_driver
->init_termios
.c_cflag
= B38400
| CS8
| CREAD
;
709 pts_driver
->init_termios
.c_ispeed
= 38400;
710 pts_driver
->init_termios
.c_ospeed
= 38400;
711 pts_driver
->flags
= TTY_DRIVER_RESET_TERMIOS
| TTY_DRIVER_REAL_RAW
|
712 TTY_DRIVER_DYNAMIC_DEV
| TTY_DRIVER_DEVPTS_MEM
;
713 pts_driver
->other
= ptm_driver
;
714 tty_set_operations(pts_driver
, &pty_unix98_ops
);
716 if (tty_register_driver(ptm_driver
))
717 panic("Couldn't register Unix98 ptm driver");
718 if (tty_register_driver(pts_driver
))
719 panic("Couldn't register Unix98 pts driver");
721 /* Now create the /dev/ptmx special device */
722 tty_default_fops(&ptmx_fops
);
723 ptmx_fops
.open
= ptmx_open
;
725 cdev_init(&ptmx_cdev
, &ptmx_fops
);
726 if (cdev_add(&ptmx_cdev
, MKDEV(TTYAUX_MAJOR
, 2), 1) ||
727 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 2), 1, "/dev/ptmx") < 0)
728 panic("Couldn't register /dev/ptmx driver\n");
729 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 2), NULL
, "ptmx");
733 static inline void unix98_pty_init(void) { }
736 static int __init
pty_init(void)
742 module_init(pty_init
);