Merge branch 's5p-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6/kvm.git] / drivers / tty / pty.c
blob923a48585501494f8b0bcae77aa562a1104bd7dd
1 /*
2 * linux/drivers/char/pty.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * Added support for a Unix98-style ptmx device.
7 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
9 * When reading this code see also fs/devpts. In particular note that the
10 * driver_data field is used by the devpts side as a binding to the devpts
11 * inode.
14 #include <linux/module.h>
16 #include <linux/errno.h>
17 #include <linux/interrupt.h>
18 #include <linux/tty.h>
19 #include <linux/tty_flip.h>
20 #include <linux/fcntl.h>
21 #include <linux/sched.h>
22 #include <linux/string.h>
23 #include <linux/major.h>
24 #include <linux/mm.h>
25 #include <linux/init.h>
26 #include <linux/smp_lock.h>
27 #include <linux/sysctl.h>
28 #include <linux/device.h>
29 #include <linux/uaccess.h>
30 #include <linux/bitops.h>
31 #include <linux/devpts_fs.h>
32 #include <linux/slab.h>
34 #include <asm/system.h>
36 #ifdef CONFIG_UNIX98_PTYS
37 static struct tty_driver *ptm_driver;
38 static struct tty_driver *pts_driver;
39 #endif
41 static void pty_close(struct tty_struct *tty, struct file *filp)
43 BUG_ON(!tty);
44 if (tty->driver->subtype == PTY_TYPE_MASTER)
45 WARN_ON(tty->count > 1);
46 else {
47 if (tty->count > 2)
48 return;
50 wake_up_interruptible(&tty->read_wait);
51 wake_up_interruptible(&tty->write_wait);
52 tty->packet = 0;
53 if (!tty->link)
54 return;
55 tty->link->packet = 0;
56 set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
57 wake_up_interruptible(&tty->link->read_wait);
58 wake_up_interruptible(&tty->link->write_wait);
59 if (tty->driver->subtype == PTY_TYPE_MASTER) {
60 set_bit(TTY_OTHER_CLOSED, &tty->flags);
61 #ifdef CONFIG_UNIX98_PTYS
62 if (tty->driver == ptm_driver)
63 devpts_pty_kill(tty->link);
64 #endif
65 tty_unlock();
66 tty_vhangup(tty->link);
67 tty_lock();
72 * The unthrottle routine is called by the line discipline to signal
73 * that it can receive more characters. For PTY's, the TTY_THROTTLED
74 * flag is always set, to force the line discipline to always call the
75 * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
76 * characters in the queue. This is necessary since each time this
77 * happens, we need to wake up any sleeping processes that could be
78 * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
79 * for the pty buffer to be drained.
81 static void pty_unthrottle(struct tty_struct *tty)
83 tty_wakeup(tty->link);
84 set_bit(TTY_THROTTLED, &tty->flags);
87 /**
88 * pty_space - report space left for writing
89 * @to: tty we are writing into
91 * The tty buffers allow 64K but we sneak a peak and clip at 8K this
92 * allows a lot of overspill room for echo and other fun messes to
93 * be handled properly
96 static int pty_space(struct tty_struct *to)
98 int n = 8192 - to->buf.memory_used;
99 if (n < 0)
100 return 0;
101 return n;
105 * pty_write - write to a pty
106 * @tty: the tty we write from
107 * @buf: kernel buffer of data
108 * @count: bytes to write
110 * Our "hardware" write method. Data is coming from the ldisc which
111 * may be in a non sleeping state. We simply throw this at the other
112 * end of the link as if we were an IRQ handler receiving stuff for
113 * the other side of the pty/tty pair.
116 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
118 struct tty_struct *to = tty->link;
120 if (tty->stopped)
121 return 0;
123 if (c > 0) {
124 /* Stuff the data into the input queue of the other end */
125 c = tty_insert_flip_string(to, buf, c);
126 /* And shovel */
127 if (c) {
128 tty_flip_buffer_push(to);
129 tty_wakeup(tty);
132 return c;
136 * pty_write_room - write space
137 * @tty: tty we are writing from
139 * Report how many bytes the ldisc can send into the queue for
140 * the other device.
143 static int pty_write_room(struct tty_struct *tty)
145 if (tty->stopped)
146 return 0;
147 return pty_space(tty->link);
151 * pty_chars_in_buffer - characters currently in our tx queue
152 * @tty: our tty
154 * Report how much we have in the transmit queue. As everything is
155 * instantly at the other end this is easy to implement.
158 static int pty_chars_in_buffer(struct tty_struct *tty)
160 return 0;
163 /* Set the lock flag on a pty */
164 static int pty_set_lock(struct tty_struct *tty, int __user *arg)
166 int val;
167 if (get_user(val, arg))
168 return -EFAULT;
169 if (val)
170 set_bit(TTY_PTY_LOCK, &tty->flags);
171 else
172 clear_bit(TTY_PTY_LOCK, &tty->flags);
173 return 0;
176 /* Send a signal to the slave */
177 static int pty_signal(struct tty_struct *tty, int sig)
179 unsigned long flags;
180 struct pid *pgrp;
182 if (tty->link) {
183 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
184 pgrp = get_pid(tty->link->pgrp);
185 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
187 kill_pgrp(pgrp, sig, 1);
188 put_pid(pgrp);
190 return 0;
193 static void pty_flush_buffer(struct tty_struct *tty)
195 struct tty_struct *to = tty->link;
196 unsigned long flags;
198 if (!to)
199 return;
200 /* tty_buffer_flush(to); FIXME */
201 if (to->packet) {
202 spin_lock_irqsave(&tty->ctrl_lock, flags);
203 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
204 wake_up_interruptible(&to->read_wait);
205 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
209 static int pty_open(struct tty_struct *tty, struct file *filp)
211 int retval = -ENODEV;
213 if (!tty || !tty->link)
214 goto out;
216 retval = -EIO;
217 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
218 goto out;
219 if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
220 goto out;
221 if (tty->link->count != 1)
222 goto out;
224 clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
225 set_bit(TTY_THROTTLED, &tty->flags);
226 retval = 0;
227 out:
228 return retval;
231 static void pty_set_termios(struct tty_struct *tty,
232 struct ktermios *old_termios)
234 tty->termios->c_cflag &= ~(CSIZE | PARENB);
235 tty->termios->c_cflag |= (CS8 | CREAD);
239 * pty_do_resize - resize event
240 * @tty: tty being resized
241 * @ws: window size being set.
243 * Update the termios variables and send the necessary signals to
244 * peform a terminal resize correctly
247 int pty_resize(struct tty_struct *tty, struct winsize *ws)
249 struct pid *pgrp, *rpgrp;
250 unsigned long flags;
251 struct tty_struct *pty = tty->link;
253 /* For a PTY we need to lock the tty side */
254 mutex_lock(&tty->termios_mutex);
255 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
256 goto done;
258 /* Get the PID values and reference them so we can
259 avoid holding the tty ctrl lock while sending signals.
260 We need to lock these individually however. */
262 spin_lock_irqsave(&tty->ctrl_lock, flags);
263 pgrp = get_pid(tty->pgrp);
264 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
266 spin_lock_irqsave(&pty->ctrl_lock, flags);
267 rpgrp = get_pid(pty->pgrp);
268 spin_unlock_irqrestore(&pty->ctrl_lock, flags);
270 if (pgrp)
271 kill_pgrp(pgrp, SIGWINCH, 1);
272 if (rpgrp != pgrp && rpgrp)
273 kill_pgrp(rpgrp, SIGWINCH, 1);
275 put_pid(pgrp);
276 put_pid(rpgrp);
278 tty->winsize = *ws;
279 pty->winsize = *ws; /* Never used so will go away soon */
280 done:
281 mutex_unlock(&tty->termios_mutex);
282 return 0;
285 /* Traditional BSD devices */
286 #ifdef CONFIG_LEGACY_PTYS
288 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
290 struct tty_struct *o_tty;
291 int idx = tty->index;
292 int retval;
294 o_tty = alloc_tty_struct();
295 if (!o_tty)
296 return -ENOMEM;
297 if (!try_module_get(driver->other->owner)) {
298 /* This cannot in fact currently happen */
299 free_tty_struct(o_tty);
300 return -ENOMEM;
302 initialize_tty_struct(o_tty, driver->other, idx);
304 /* We always use new tty termios data so we can do this
305 the easy way .. */
306 retval = tty_init_termios(tty);
307 if (retval)
308 goto free_mem_out;
310 retval = tty_init_termios(o_tty);
311 if (retval) {
312 tty_free_termios(tty);
313 goto free_mem_out;
317 * Everything allocated ... set up the o_tty structure.
319 driver->other->ttys[idx] = o_tty;
320 tty_driver_kref_get(driver->other);
321 if (driver->subtype == PTY_TYPE_MASTER)
322 o_tty->count++;
323 /* Establish the links in both directions */
324 tty->link = o_tty;
325 o_tty->link = tty;
327 tty_driver_kref_get(driver);
328 tty->count++;
329 driver->ttys[idx] = tty;
330 return 0;
331 free_mem_out:
332 module_put(o_tty->driver->owner);
333 free_tty_struct(o_tty);
334 return -ENOMEM;
337 static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
338 unsigned int cmd, unsigned long arg)
340 switch (cmd) {
341 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
342 return pty_set_lock(tty, (int __user *) arg);
343 case TIOCSIG: /* Send signal to other side of pty */
344 return pty_signal(tty, (int) arg);
346 return -ENOIOCTLCMD;
349 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
350 module_param(legacy_count, int, 0);
353 * The master side of a pty can do TIOCSPTLCK and thus
354 * has pty_bsd_ioctl.
356 static const struct tty_operations master_pty_ops_bsd = {
357 .install = pty_install,
358 .open = pty_open,
359 .close = pty_close,
360 .write = pty_write,
361 .write_room = pty_write_room,
362 .flush_buffer = pty_flush_buffer,
363 .chars_in_buffer = pty_chars_in_buffer,
364 .unthrottle = pty_unthrottle,
365 .set_termios = pty_set_termios,
366 .ioctl = pty_bsd_ioctl,
367 .resize = pty_resize
370 static const struct tty_operations slave_pty_ops_bsd = {
371 .install = pty_install,
372 .open = pty_open,
373 .close = pty_close,
374 .write = pty_write,
375 .write_room = pty_write_room,
376 .flush_buffer = pty_flush_buffer,
377 .chars_in_buffer = pty_chars_in_buffer,
378 .unthrottle = pty_unthrottle,
379 .set_termios = pty_set_termios,
380 .resize = pty_resize
383 static void __init legacy_pty_init(void)
385 struct tty_driver *pty_driver, *pty_slave_driver;
387 if (legacy_count <= 0)
388 return;
390 pty_driver = alloc_tty_driver(legacy_count);
391 if (!pty_driver)
392 panic("Couldn't allocate pty driver");
394 pty_slave_driver = alloc_tty_driver(legacy_count);
395 if (!pty_slave_driver)
396 panic("Couldn't allocate pty slave driver");
398 pty_driver->owner = THIS_MODULE;
399 pty_driver->driver_name = "pty_master";
400 pty_driver->name = "pty";
401 pty_driver->major = PTY_MASTER_MAJOR;
402 pty_driver->minor_start = 0;
403 pty_driver->type = TTY_DRIVER_TYPE_PTY;
404 pty_driver->subtype = PTY_TYPE_MASTER;
405 pty_driver->init_termios = tty_std_termios;
406 pty_driver->init_termios.c_iflag = 0;
407 pty_driver->init_termios.c_oflag = 0;
408 pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
409 pty_driver->init_termios.c_lflag = 0;
410 pty_driver->init_termios.c_ispeed = 38400;
411 pty_driver->init_termios.c_ospeed = 38400;
412 pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
413 pty_driver->other = pty_slave_driver;
414 tty_set_operations(pty_driver, &master_pty_ops_bsd);
416 pty_slave_driver->owner = THIS_MODULE;
417 pty_slave_driver->driver_name = "pty_slave";
418 pty_slave_driver->name = "ttyp";
419 pty_slave_driver->major = PTY_SLAVE_MAJOR;
420 pty_slave_driver->minor_start = 0;
421 pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
422 pty_slave_driver->subtype = PTY_TYPE_SLAVE;
423 pty_slave_driver->init_termios = tty_std_termios;
424 pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
425 pty_slave_driver->init_termios.c_ispeed = 38400;
426 pty_slave_driver->init_termios.c_ospeed = 38400;
427 pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
428 TTY_DRIVER_REAL_RAW;
429 pty_slave_driver->other = pty_driver;
430 tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
432 if (tty_register_driver(pty_driver))
433 panic("Couldn't register pty driver");
434 if (tty_register_driver(pty_slave_driver))
435 panic("Couldn't register pty slave driver");
437 #else
438 static inline void legacy_pty_init(void) { }
439 #endif
441 /* Unix98 devices */
442 #ifdef CONFIG_UNIX98_PTYS
444 * sysctl support for setting limits on the number of Unix98 ptys allocated.
445 * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
447 int pty_limit = NR_UNIX98_PTY_DEFAULT;
448 static int pty_limit_min;
449 static int pty_limit_max = NR_UNIX98_PTY_MAX;
450 static int pty_count;
452 static struct cdev ptmx_cdev;
454 static struct ctl_table pty_table[] = {
456 .procname = "max",
457 .maxlen = sizeof(int),
458 .mode = 0644,
459 .data = &pty_limit,
460 .proc_handler = proc_dointvec_minmax,
461 .extra1 = &pty_limit_min,
462 .extra2 = &pty_limit_max,
463 }, {
464 .procname = "nr",
465 .maxlen = sizeof(int),
466 .mode = 0444,
467 .data = &pty_count,
468 .proc_handler = proc_dointvec,
473 static struct ctl_table pty_kern_table[] = {
475 .procname = "pty",
476 .mode = 0555,
477 .child = pty_table,
482 static struct ctl_table pty_root_table[] = {
484 .procname = "kernel",
485 .mode = 0555,
486 .child = pty_kern_table,
492 static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
493 unsigned int cmd, unsigned long arg)
495 switch (cmd) {
496 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
497 return pty_set_lock(tty, (int __user *)arg);
498 case TIOCGPTN: /* Get PT Number */
499 return put_user(tty->index, (unsigned int __user *)arg);
500 case TIOCSIG: /* Send signal to other side of pty */
501 return pty_signal(tty, (int) arg);
504 return -ENOIOCTLCMD;
508 * ptm_unix98_lookup - find a pty master
509 * @driver: ptm driver
510 * @idx: tty index
512 * Look up a pty master device. Called under the tty_mutex for now.
513 * This provides our locking.
516 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
517 struct inode *ptm_inode, int idx)
519 struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
520 if (tty)
521 tty = tty->link;
522 return tty;
526 * pts_unix98_lookup - find a pty slave
527 * @driver: pts driver
528 * @idx: tty index
530 * Look up a pty master device. Called under the tty_mutex for now.
531 * This provides our locking.
534 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
535 struct inode *pts_inode, int idx)
537 struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
538 /* Master must be open before slave */
539 if (!tty)
540 return ERR_PTR(-EIO);
541 return tty;
544 static void pty_unix98_shutdown(struct tty_struct *tty)
546 /* We have our own method as we don't use the tty index */
547 kfree(tty->termios);
550 /* We have no need to install and remove our tty objects as devpts does all
551 the work for us */
553 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
555 struct tty_struct *o_tty;
556 int idx = tty->index;
558 o_tty = alloc_tty_struct();
559 if (!o_tty)
560 return -ENOMEM;
561 if (!try_module_get(driver->other->owner)) {
562 /* This cannot in fact currently happen */
563 free_tty_struct(o_tty);
564 return -ENOMEM;
566 initialize_tty_struct(o_tty, driver->other, idx);
568 tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
569 if (tty->termios == NULL)
570 goto free_mem_out;
571 *tty->termios = driver->init_termios;
572 tty->termios_locked = tty->termios + 1;
574 o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
575 if (o_tty->termios == NULL)
576 goto free_mem_out;
577 *o_tty->termios = driver->other->init_termios;
578 o_tty->termios_locked = o_tty->termios + 1;
580 tty_driver_kref_get(driver->other);
581 if (driver->subtype == PTY_TYPE_MASTER)
582 o_tty->count++;
583 /* Establish the links in both directions */
584 tty->link = o_tty;
585 o_tty->link = tty;
587 * All structures have been allocated, so now we install them.
588 * Failures after this point use release_tty to clean up, so
589 * there's no need to null out the local pointers.
591 tty_driver_kref_get(driver);
592 tty->count++;
593 pty_count++;
594 return 0;
595 free_mem_out:
596 kfree(o_tty->termios);
597 module_put(o_tty->driver->owner);
598 free_tty_struct(o_tty);
599 kfree(tty->termios);
600 return -ENOMEM;
603 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
605 pty_count--;
608 static const struct tty_operations ptm_unix98_ops = {
609 .lookup = ptm_unix98_lookup,
610 .install = pty_unix98_install,
611 .remove = pty_unix98_remove,
612 .open = pty_open,
613 .close = pty_close,
614 .write = pty_write,
615 .write_room = pty_write_room,
616 .flush_buffer = pty_flush_buffer,
617 .chars_in_buffer = pty_chars_in_buffer,
618 .unthrottle = pty_unthrottle,
619 .set_termios = pty_set_termios,
620 .ioctl = pty_unix98_ioctl,
621 .shutdown = pty_unix98_shutdown,
622 .resize = pty_resize
625 static const struct tty_operations pty_unix98_ops = {
626 .lookup = pts_unix98_lookup,
627 .install = pty_unix98_install,
628 .remove = pty_unix98_remove,
629 .open = pty_open,
630 .close = pty_close,
631 .write = pty_write,
632 .write_room = pty_write_room,
633 .flush_buffer = pty_flush_buffer,
634 .chars_in_buffer = pty_chars_in_buffer,
635 .unthrottle = pty_unthrottle,
636 .set_termios = pty_set_termios,
637 .shutdown = pty_unix98_shutdown
641 * ptmx_open - open a unix 98 pty master
642 * @inode: inode of device file
643 * @filp: file pointer to tty
645 * Allocate a unix98 pty master device from the ptmx driver.
647 * Locking: tty_mutex protects the init_dev work. tty->count should
648 * protect the rest.
649 * allocated_ptys_lock handles the list of free pty numbers
652 static int ptmx_open(struct inode *inode, struct file *filp)
654 struct tty_struct *tty;
655 int retval;
656 int index;
658 nonseekable_open(inode, filp);
660 /* find a device that is not in use. */
661 tty_lock();
662 index = devpts_new_index(inode);
663 tty_unlock();
664 if (index < 0)
665 return index;
667 mutex_lock(&tty_mutex);
668 tty_lock();
669 tty = tty_init_dev(ptm_driver, index, 1);
670 mutex_unlock(&tty_mutex);
672 if (IS_ERR(tty)) {
673 retval = PTR_ERR(tty);
674 goto out;
677 set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
679 retval = tty_add_file(tty, filp);
680 if (retval)
681 goto out;
683 retval = devpts_pty_new(inode, tty->link);
684 if (retval)
685 goto out1;
687 retval = ptm_driver->ops->open(tty, filp);
688 if (retval)
689 goto out2;
690 out1:
691 tty_unlock();
692 return retval;
693 out2:
694 tty_unlock();
695 tty_release(inode, filp);
696 return retval;
697 out:
698 devpts_kill_index(inode, index);
699 tty_unlock();
700 return retval;
703 static struct file_operations ptmx_fops;
705 static void __init unix98_pty_init(void)
707 ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
708 if (!ptm_driver)
709 panic("Couldn't allocate Unix98 ptm driver");
710 pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
711 if (!pts_driver)
712 panic("Couldn't allocate Unix98 pts driver");
714 ptm_driver->owner = THIS_MODULE;
715 ptm_driver->driver_name = "pty_master";
716 ptm_driver->name = "ptm";
717 ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
718 ptm_driver->minor_start = 0;
719 ptm_driver->type = TTY_DRIVER_TYPE_PTY;
720 ptm_driver->subtype = PTY_TYPE_MASTER;
721 ptm_driver->init_termios = tty_std_termios;
722 ptm_driver->init_termios.c_iflag = 0;
723 ptm_driver->init_termios.c_oflag = 0;
724 ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
725 ptm_driver->init_termios.c_lflag = 0;
726 ptm_driver->init_termios.c_ispeed = 38400;
727 ptm_driver->init_termios.c_ospeed = 38400;
728 ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
729 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
730 ptm_driver->other = pts_driver;
731 tty_set_operations(ptm_driver, &ptm_unix98_ops);
733 pts_driver->owner = THIS_MODULE;
734 pts_driver->driver_name = "pty_slave";
735 pts_driver->name = "pts";
736 pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
737 pts_driver->minor_start = 0;
738 pts_driver->type = TTY_DRIVER_TYPE_PTY;
739 pts_driver->subtype = PTY_TYPE_SLAVE;
740 pts_driver->init_termios = tty_std_termios;
741 pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
742 pts_driver->init_termios.c_ispeed = 38400;
743 pts_driver->init_termios.c_ospeed = 38400;
744 pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
745 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
746 pts_driver->other = ptm_driver;
747 tty_set_operations(pts_driver, &pty_unix98_ops);
749 if (tty_register_driver(ptm_driver))
750 panic("Couldn't register Unix98 ptm driver");
751 if (tty_register_driver(pts_driver))
752 panic("Couldn't register Unix98 pts driver");
754 register_sysctl_table(pty_root_table);
756 /* Now create the /dev/ptmx special device */
757 tty_default_fops(&ptmx_fops);
758 ptmx_fops.open = ptmx_open;
760 cdev_init(&ptmx_cdev, &ptmx_fops);
761 if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
762 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
763 panic("Couldn't register /dev/ptmx driver\n");
764 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
767 #else
768 static inline void unix98_pty_init(void) { }
769 #endif
771 static int __init pty_init(void)
773 legacy_pty_init();
774 unix98_pty_init();
775 return 0;
777 module_init(pty_init);