Add an instance parameter devpts interfaces
[linux-2.6] / drivers / char / pty.c
1 /*
2  *  linux/drivers/char/pty.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  *
6  *  Added support for a Unix98-style ptmx device.
7  *    -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
8  *  Added TTY_DO_WRITE_WAKEUP to enable n_tty to send POLL_OUT to
9  *      waiting writers -- Sapan Bhatia <sapan@corewars.org>
10  *
11  *
12  */
13
14 #include <linux/module.h>       /* For EXPORT_SYMBOL */
15
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/string.h>
22 #include <linux/major.h>
23 #include <linux/mm.h>
24 #include <linux/init.h>
25 #include <linux/sysctl.h>
26 #include <linux/device.h>
27
28 #include <asm/uaccess.h>
29 #include <asm/system.h>
30 #include <linux/bitops.h>
31 #include <linux/devpts_fs.h>
32
33 /* These are global because they are accessed in tty_io.c */
34 #ifdef CONFIG_UNIX98_PTYS
35 struct tty_driver *ptm_driver;
36 static struct tty_driver *pts_driver;
37 #endif
38
39 static void pty_close(struct tty_struct * tty, struct file * filp)
40 {
41         if (!tty)
42                 return;
43         if (tty->driver->subtype == PTY_TYPE_MASTER) {
44                 if (tty->count > 1)
45                         printk("master pty_close: count = %d!!\n", tty->count);
46         } else {
47                 if (tty->count > 2)
48                         return;
49         }
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_vhangup(tty->link);
66         }
67 }
68
69 /*
70  * The unthrottle routine is called by the line discipline to signal
71  * that it can receive more characters.  For PTY's, the TTY_THROTTLED
72  * flag is always set, to force the line discipline to always call the
73  * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE 
74  * characters in the queue.  This is necessary since each time this
75  * happens, we need to wake up any sleeping processes that could be
76  * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
77  * for the pty buffer to be drained.
78  */
79 static void pty_unthrottle(struct tty_struct * tty)
80 {
81         struct tty_struct *o_tty = tty->link;
82
83         if (!o_tty)
84                 return;
85
86         tty_wakeup(o_tty);
87         set_bit(TTY_THROTTLED, &tty->flags);
88 }
89
90 /*
91  * WSH 05/24/97: modified to 
92  *   (1) use space in tty->flip instead of a shared temp buffer
93  *       The flip buffers aren't being used for a pty, so there's lots
94  *       of space available.  The buffer is protected by a per-pty
95  *       semaphore that should almost never come under contention.
96  *   (2) avoid redundant copying for cases where count >> receive_room
97  * N.B. Calls from user space may now return an error code instead of
98  * a count.
99  *
100  * FIXME: Our pty_write method is called with our ldisc lock held but
101  * not our partners. We can't just take the other one blindly without
102  * risking deadlocks.
103  */
104 static int pty_write(struct tty_struct * tty, const unsigned char *buf, int count)
105 {
106         struct tty_struct *to = tty->link;
107         int     c;
108
109         if (!to || tty->stopped)
110                 return 0;
111
112         c = to->receive_room;
113         if (c > count)
114                 c = count;
115         to->ldisc.ops->receive_buf(to, buf, NULL, c);
116         
117         return c;
118 }
119
120 static int pty_write_room(struct tty_struct *tty)
121 {
122         struct tty_struct *to = tty->link;
123
124         if (!to || tty->stopped)
125                 return 0;
126
127         return to->receive_room;
128 }
129
130 /*
131  *      WSH 05/24/97:  Modified for asymmetric MASTER/SLAVE behavior
132  *      The chars_in_buffer() value is used by the ldisc select() function 
133  *      to hold off writing when chars_in_buffer > WAKEUP_CHARS (== 256).
134  *      The pty driver chars_in_buffer() Master/Slave must behave differently:
135  *
136  *      The Master side needs to allow typed-ahead commands to accumulate
137  *      while being canonicalized, so we report "our buffer" as empty until
138  *      some threshold is reached, and then report the count. (Any count >
139  *      WAKEUP_CHARS is regarded by select() as "full".)  To avoid deadlock 
140  *      the count returned must be 0 if no canonical data is available to be 
141  *      read. (The N_TTY ldisc.chars_in_buffer now knows this.)
142  *  
143  *      The Slave side passes all characters in raw mode to the Master side's
144  *      buffer where they can be read immediately, so in this case we can
145  *      return the true count in the buffer.
146  */
147 static int pty_chars_in_buffer(struct tty_struct *tty)
148 {
149         struct tty_struct *to = tty->link;
150         int count;
151
152         /* We should get the line discipline lock for "tty->link" */
153         if (!to || !to->ldisc.ops->chars_in_buffer)
154                 return 0;
155
156         /* The ldisc must report 0 if no characters available to be read */
157         count = to->ldisc.ops->chars_in_buffer(to);
158
159         if (tty->driver->subtype == PTY_TYPE_SLAVE) return count;
160
161         /* Master side driver ... if the other side's read buffer is less than 
162          * half full, return 0 to allow writers to proceed; otherwise return
163          * the count.  This leaves a comfortable margin to avoid overflow, 
164          * and still allows half a buffer's worth of typed-ahead commands.
165          */
166         return ((count < N_TTY_BUF_SIZE/2) ? 0 : count);
167 }
168
169 /* Set the lock flag on a pty */
170 static int pty_set_lock(struct tty_struct *tty, int __user * arg)
171 {
172         int val;
173         if (get_user(val,arg))
174                 return -EFAULT;
175         if (val)
176                 set_bit(TTY_PTY_LOCK, &tty->flags);
177         else
178                 clear_bit(TTY_PTY_LOCK, &tty->flags);
179         return 0;
180 }
181
182 static void pty_flush_buffer(struct tty_struct *tty)
183 {
184         struct tty_struct *to = tty->link;
185         unsigned long flags;
186         
187         if (!to)
188                 return;
189         
190         if (to->ldisc.ops->flush_buffer)
191                 to->ldisc.ops->flush_buffer(to);
192         
193         if (to->packet) {
194                 spin_lock_irqsave(&tty->ctrl_lock, flags);
195                 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
196                 wake_up_interruptible(&to->read_wait);
197                 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
198         }
199 }
200
201 static int pty_open(struct tty_struct *tty, struct file * filp)
202 {
203         int     retval = -ENODEV;
204
205         if (!tty || !tty->link)
206                 goto out;
207
208         retval = -EIO;
209         if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
210                 goto out;
211         if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
212                 goto out;
213         if (tty->link->count != 1)
214                 goto out;
215
216         clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
217         set_bit(TTY_THROTTLED, &tty->flags);
218         set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
219         retval = 0;
220 out:
221         return retval;
222 }
223
224 static void pty_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
225 {
226         tty->termios->c_cflag &= ~(CSIZE | PARENB);
227         tty->termios->c_cflag |= (CS8 | CREAD);
228 }
229
230 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
231 {
232         struct tty_struct *o_tty;
233         int idx = tty->index;
234         int retval;
235
236         o_tty = alloc_tty_struct();
237         if (!o_tty)
238                 return -ENOMEM;
239         if (!try_module_get(driver->other->owner)) {
240                 /* This cannot in fact currently happen */
241                 free_tty_struct(o_tty);
242                 return -ENOMEM;
243         }
244         initialize_tty_struct(o_tty, driver->other, idx);
245
246         /* We always use new tty termios data so we can do this
247            the easy way .. */
248         retval = tty_init_termios(tty);
249         if (retval)
250                 goto free_mem_out;
251
252         retval = tty_init_termios(o_tty);
253         if (retval) {
254                 tty_free_termios(tty);
255                 goto free_mem_out;
256         }
257         
258         /*
259          * Everything allocated ... set up the o_tty structure.
260          */
261         driver->other->ttys[idx] = o_tty;
262         tty_driver_kref_get(driver->other);
263         if (driver->subtype == PTY_TYPE_MASTER)
264                 o_tty->count++;
265         /* Establish the links in both directions */
266         tty->link   = o_tty;
267         o_tty->link = tty;
268
269         tty_driver_kref_get(driver);
270         tty->count++;
271         driver->ttys[idx] = tty;
272         return 0;
273 free_mem_out:
274         module_put(o_tty->driver->owner);
275         free_tty_struct(o_tty);
276         return -ENOMEM;
277 }
278
279
280 static const struct tty_operations pty_ops = {
281         .install = pty_install,
282         .open = pty_open,
283         .close = pty_close,
284         .write = pty_write,
285         .write_room = pty_write_room,
286         .flush_buffer = pty_flush_buffer,
287         .chars_in_buffer = pty_chars_in_buffer,
288         .unthrottle = pty_unthrottle,
289         .set_termios = pty_set_termios,
290 };
291
292 /* Traditional BSD devices */
293 #ifdef CONFIG_LEGACY_PTYS
294 static struct tty_driver *pty_driver, *pty_slave_driver;
295
296 static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
297                          unsigned int cmd, unsigned long arg)
298 {
299         switch (cmd) {
300         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
301                 return pty_set_lock(tty, (int __user *) arg);
302         }
303         return -ENOIOCTLCMD;
304 }
305
306 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
307 module_param(legacy_count, int, 0);
308
309 static const struct tty_operations pty_ops_bsd = {
310         .open = pty_open,
311         .close = pty_close,
312         .write = pty_write,
313         .write_room = pty_write_room,
314         .flush_buffer = pty_flush_buffer,
315         .chars_in_buffer = pty_chars_in_buffer,
316         .unthrottle = pty_unthrottle,
317         .set_termios = pty_set_termios,
318         .ioctl = pty_bsd_ioctl,
319 };
320
321 static void __init legacy_pty_init(void)
322 {
323         if (legacy_count <= 0)
324                 return;
325
326         pty_driver = alloc_tty_driver(legacy_count);
327         if (!pty_driver)
328                 panic("Couldn't allocate pty driver");
329
330         pty_slave_driver = alloc_tty_driver(legacy_count);
331         if (!pty_slave_driver)
332                 panic("Couldn't allocate pty slave driver");
333
334         pty_driver->owner = THIS_MODULE;
335         pty_driver->driver_name = "pty_master";
336         pty_driver->name = "pty";
337         pty_driver->major = PTY_MASTER_MAJOR;
338         pty_driver->minor_start = 0;
339         pty_driver->type = TTY_DRIVER_TYPE_PTY;
340         pty_driver->subtype = PTY_TYPE_MASTER;
341         pty_driver->init_termios = tty_std_termios;
342         pty_driver->init_termios.c_iflag = 0;
343         pty_driver->init_termios.c_oflag = 0;
344         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
345         pty_driver->init_termios.c_lflag = 0;
346         pty_driver->init_termios.c_ispeed = 38400;
347         pty_driver->init_termios.c_ospeed = 38400;
348         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
349         pty_driver->other = pty_slave_driver;
350         tty_set_operations(pty_driver, &pty_ops);
351
352         pty_slave_driver->owner = THIS_MODULE;
353         pty_slave_driver->driver_name = "pty_slave";
354         pty_slave_driver->name = "ttyp";
355         pty_slave_driver->major = PTY_SLAVE_MAJOR;
356         pty_slave_driver->minor_start = 0;
357         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
358         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
359         pty_slave_driver->init_termios = tty_std_termios;
360         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
361         pty_slave_driver->init_termios.c_ispeed = 38400;
362         pty_slave_driver->init_termios.c_ospeed = 38400;
363         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
364                                         TTY_DRIVER_REAL_RAW;
365         pty_slave_driver->other = pty_driver;
366         tty_set_operations(pty_slave_driver, &pty_ops);
367
368         if (tty_register_driver(pty_driver))
369                 panic("Couldn't register pty driver");
370         if (tty_register_driver(pty_slave_driver))
371                 panic("Couldn't register pty slave driver");
372 }
373 #else
374 static inline void legacy_pty_init(void) { }
375 #endif
376
377 /* Unix98 devices */
378 #ifdef CONFIG_UNIX98_PTYS
379 /*
380  * sysctl support for setting limits on the number of Unix98 ptys allocated.
381  * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
382  */
383 int pty_limit = NR_UNIX98_PTY_DEFAULT;
384 static int pty_limit_min = 0;
385 static int pty_limit_max = NR_UNIX98_PTY_MAX;
386 static int pty_count = 0;
387
388 static struct cdev ptmx_cdev;
389
390 static struct ctl_table pty_table[] = {
391         {
392                 .ctl_name       = PTY_MAX,
393                 .procname       = "max",
394                 .maxlen         = sizeof(int),
395                 .mode           = 0644,
396                 .data           = &pty_limit,
397                 .proc_handler   = &proc_dointvec_minmax,
398                 .strategy       = &sysctl_intvec,
399                 .extra1         = &pty_limit_min,
400                 .extra2         = &pty_limit_max,
401         }, {
402                 .ctl_name       = PTY_NR,
403                 .procname       = "nr",
404                 .maxlen         = sizeof(int),
405                 .mode           = 0444,
406                 .data           = &pty_count,
407                 .proc_handler   = &proc_dointvec,
408         }, {
409                 .ctl_name       = 0
410         }
411 };
412
413 static struct ctl_table pty_kern_table[] = {
414         {
415                 .ctl_name       = KERN_PTY,
416                 .procname       = "pty",
417                 .mode           = 0555,
418                 .child          = pty_table,
419         },
420         {}
421 };
422
423 static struct ctl_table pty_root_table[] = {
424         {
425                 .ctl_name       = CTL_KERN,
426                 .procname       = "kernel",
427                 .mode           = 0555,
428                 .child          = pty_kern_table,
429         },
430         {}
431 };
432
433
434 static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
435                             unsigned int cmd, unsigned long arg)
436 {
437         switch (cmd) {
438         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
439                 return pty_set_lock(tty, (int __user *)arg);
440         case TIOCGPTN: /* Get PT Number */
441                 return put_user(tty->index, (unsigned int __user *)arg);
442         }
443
444         return -ENOIOCTLCMD;
445 }
446
447 /**
448  *      ptm_unix98_lookup       -       find a pty master
449  *      @driver: ptm driver
450  *      @idx: tty index
451  *
452  *      Look up a pty master device. Called under the tty_mutex for now.
453  *      This provides our locking.
454  */
455
456 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
457                 struct inode *ptm_inode, int idx)
458 {
459         struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
460         if (tty)
461                 tty = tty->link;
462         return tty;
463 }
464
465 /**
466  *      pts_unix98_lookup       -       find a pty slave
467  *      @driver: pts driver
468  *      @idx: tty index
469  *
470  *      Look up a pty master device. Called under the tty_mutex for now.
471  *      This provides our locking.
472  */
473
474 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
475                 struct inode *pts_inode, int idx)
476 {
477         struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
478         /* Master must be open before slave */
479         if (!tty)
480                 return ERR_PTR(-EIO);
481         return tty;
482 }
483
484 static void pty_unix98_shutdown(struct tty_struct *tty)
485 {
486         /* We have our own method as we don't use the tty index */
487         kfree(tty->termios);
488         kfree(tty->termios_locked);
489 }
490
491 /* We have no need to install and remove our tty objects as devpts does all
492    the work for us */
493
494 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
495 {
496         struct tty_struct *o_tty;
497         int idx = tty->index;
498
499         o_tty = alloc_tty_struct();
500         if (!o_tty)
501                 return -ENOMEM;
502         if (!try_module_get(driver->other->owner)) {
503                 /* This cannot in fact currently happen */
504                 free_tty_struct(o_tty);
505                 return -ENOMEM;
506         }
507         initialize_tty_struct(o_tty, driver->other, idx);
508
509         tty->termios = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
510         if (tty->termios == NULL)
511                 goto free_mem_out;
512         *tty->termios = driver->init_termios;
513         tty->termios_locked = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
514         if (tty->termios_locked == NULL)
515                 goto free_mem_out;
516         o_tty->termios = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
517         if (o_tty->termios == NULL)
518                 goto free_mem_out;
519         *o_tty->termios = driver->other->init_termios;
520         o_tty->termios_locked = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
521         if (o_tty->termios_locked == NULL)
522                 goto free_mem_out;
523
524         tty_driver_kref_get(driver->other);
525         if (driver->subtype == PTY_TYPE_MASTER)
526                 o_tty->count++;
527         /* Establish the links in both directions */
528         tty->link   = o_tty;
529         o_tty->link = tty;
530         /*
531          * All structures have been allocated, so now we install them.
532          * Failures after this point use release_tty to clean up, so
533          * there's no need to null out the local pointers.
534          */
535         tty_driver_kref_get(driver);
536         tty->count++;
537         pty_count++;
538         return 0;
539 free_mem_out:
540         kfree(o_tty->termios);
541         module_put(o_tty->driver->owner);
542         free_tty_struct(o_tty);
543         kfree(tty->termios_locked);
544         kfree(tty->termios);
545         free_tty_struct(tty);
546         module_put(driver->owner);
547         return -ENOMEM;
548 }
549
550 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
551 {
552         pty_count--;
553 }
554
555 static const struct tty_operations ptm_unix98_ops = {
556         .lookup = ptm_unix98_lookup,
557         .install = pty_unix98_install,
558         .remove = pty_unix98_remove,
559         .open = pty_open,
560         .close = pty_close,
561         .write = pty_write,
562         .write_room = pty_write_room,
563         .flush_buffer = pty_flush_buffer,
564         .chars_in_buffer = pty_chars_in_buffer,
565         .unthrottle = pty_unthrottle,
566         .set_termios = pty_set_termios,
567         .ioctl = pty_unix98_ioctl,
568         .shutdown = pty_unix98_shutdown
569 };
570
571 static const struct tty_operations pty_unix98_ops = {
572         .lookup = pts_unix98_lookup,
573         .install = pty_unix98_install,
574         .remove = pty_unix98_remove,
575         .open = pty_open,
576         .close = pty_close,
577         .write = pty_write,
578         .write_room = pty_write_room,
579         .flush_buffer = pty_flush_buffer,
580         .chars_in_buffer = pty_chars_in_buffer,
581         .unthrottle = pty_unthrottle,
582         .set_termios = pty_set_termios,
583         .shutdown = pty_unix98_shutdown
584 };
585
586 /**
587  *      ptmx_open               -       open a unix 98 pty master
588  *      @inode: inode of device file
589  *      @filp: file pointer to tty
590  *
591  *      Allocate a unix98 pty master device from the ptmx driver.
592  *
593  *      Locking: tty_mutex protects the init_dev work. tty->count should
594  *              protect the rest.
595  *              allocated_ptys_lock handles the list of free pty numbers
596  */
597
598 static int __ptmx_open(struct inode *inode, struct file *filp)
599 {
600         struct tty_struct *tty;
601         int retval;
602         int index;
603
604         nonseekable_open(inode, filp);
605
606         /* find a device that is not in use. */
607         index = devpts_new_index(inode);
608         if (index < 0)
609                 return index;
610
611         mutex_lock(&tty_mutex);
612         tty = tty_init_dev(ptm_driver, index, 1);
613         mutex_unlock(&tty_mutex);
614
615         if (IS_ERR(tty)) {
616                 retval = PTR_ERR(tty);
617                 goto out;
618         }
619
620         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
621         filp->private_data = tty;
622         file_move(filp, &tty->tty_files);
623
624         retval = devpts_pty_new(inode, tty->link);
625         if (retval)
626                 goto out1;
627
628         retval = ptm_driver->ops->open(tty, filp);
629         if (!retval)
630                 return 0;
631 out1:
632         tty_release_dev(filp);
633         return retval;
634 out:
635         devpts_kill_index(inode, index);
636         return retval;
637 }
638
639 static int ptmx_open(struct inode *inode, struct file *filp)
640 {
641         int ret;
642
643         lock_kernel();
644         ret = __ptmx_open(inode, filp);
645         unlock_kernel();
646         return ret;
647 }
648
649 static struct file_operations ptmx_fops;
650
651 static void __init unix98_pty_init(void)
652 {
653         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
654         if (!ptm_driver)
655                 panic("Couldn't allocate Unix98 ptm driver");
656         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
657         if (!pts_driver)
658                 panic("Couldn't allocate Unix98 pts driver");
659
660         ptm_driver->owner = THIS_MODULE;
661         ptm_driver->driver_name = "pty_master";
662         ptm_driver->name = "ptm";
663         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
664         ptm_driver->minor_start = 0;
665         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
666         ptm_driver->subtype = PTY_TYPE_MASTER;
667         ptm_driver->init_termios = tty_std_termios;
668         ptm_driver->init_termios.c_iflag = 0;
669         ptm_driver->init_termios.c_oflag = 0;
670         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
671         ptm_driver->init_termios.c_lflag = 0;
672         ptm_driver->init_termios.c_ispeed = 38400;
673         ptm_driver->init_termios.c_ospeed = 38400;
674         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
675                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
676         ptm_driver->other = pts_driver;
677         tty_set_operations(ptm_driver, &ptm_unix98_ops);
678
679         pts_driver->owner = THIS_MODULE;
680         pts_driver->driver_name = "pty_slave";
681         pts_driver->name = "pts";
682         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
683         pts_driver->minor_start = 0;
684         pts_driver->type = TTY_DRIVER_TYPE_PTY;
685         pts_driver->subtype = PTY_TYPE_SLAVE;
686         pts_driver->init_termios = tty_std_termios;
687         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
688         pts_driver->init_termios.c_ispeed = 38400;
689         pts_driver->init_termios.c_ospeed = 38400;
690         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
691                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
692         pts_driver->other = ptm_driver;
693         tty_set_operations(pts_driver, &pty_unix98_ops);
694         
695         if (tty_register_driver(ptm_driver))
696                 panic("Couldn't register Unix98 ptm driver");
697         if (tty_register_driver(pts_driver))
698                 panic("Couldn't register Unix98 pts driver");
699
700         register_sysctl_table(pty_root_table);  
701
702         /* Now create the /dev/ptmx special device */
703         tty_default_fops(&ptmx_fops);
704         ptmx_fops.open = ptmx_open;
705
706         cdev_init(&ptmx_cdev, &ptmx_fops);
707         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
708             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
709                 panic("Couldn't register /dev/ptmx driver\n");
710         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
711 }
712
713 #else
714 static inline void unix98_pty_init(void) { }
715 #endif
716
717 static int __init pty_init(void)
718 {
719         legacy_pty_init();
720         unix98_pty_init();
721         return 0;
722 }
723 module_init(pty_init);