53761cefa9154bb541d676b432550d61fc579efb
[linux-2.6.git] / 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  *
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.
12  */
13
14 #include <linux/module.h>
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/smp_lock.h>
26 #include <linux/sysctl.h>
27 #include <linux/device.h>
28 #include <linux/uaccess.h>
29 #include <linux/bitops.h>
30 #include <linux/devpts_fs.h>
31
32 #include <asm/system.h>
33
34 #ifdef CONFIG_UNIX98_PTYS
35 static 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         BUG_ON(!tty);
42         if (tty->driver->subtype == PTY_TYPE_MASTER)
43                 WARN_ON(tty->count > 1);
44         else {
45                 if (tty->count > 2)
46                         return;
47         }
48         wake_up_interruptible(&tty->read_wait);
49         wake_up_interruptible(&tty->write_wait);
50         tty->packet = 0;
51         if (!tty->link)
52                 return;
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                         devpts_pty_kill(tty->link);
62 #endif
63                 tty_vhangup(tty->link);
64         }
65 }
66
67 /*
68  * The unthrottle routine is called by the line discipline to signal
69  * that it can receive more characters.  For PTY's, the TTY_THROTTLED
70  * flag is always set, to force the line discipline to always call the
71  * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
72  * characters in the queue.  This is necessary since each time this
73  * happens, we need to wake up any sleeping processes that could be
74  * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
75  * for the pty buffer to be drained.
76  */
77 static void pty_unthrottle(struct tty_struct *tty)
78 {
79         tty_wakeup(tty->link);
80         set_bit(TTY_THROTTLED, &tty->flags);
81 }
82
83 /**
84  *      pty_space       -       report space left for writing
85  *      @to: tty we are writing into
86  *
87  *      The tty buffers allow 64K but we sneak a peak and clip at 8K this
88  *      allows a lot of overspill room for echo and other fun messes to
89  *      be handled properly
90  */
91
92 static int pty_space(struct tty_struct *to)
93 {
94         int n = 8192 - to->buf.memory_used;
95         if (n < 0)
96                 return 0;
97         return n;
98 }
99
100 /**
101  *      pty_write               -       write to a pty
102  *      @tty: the tty we write from
103  *      @buf: kernel buffer of data
104  *      @count: bytes to write
105  *
106  *      Our "hardware" write method. Data is coming from the ldisc which
107  *      may be in a non sleeping state. We simply throw this at the other
108  *      end of the link as if we were an IRQ handler receiving stuff for
109  *      the other side of the pty/tty pair.
110  */
111
112 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
113 {
114         struct tty_struct *to = tty->link;
115
116         if (tty->stopped)
117                 return 0;
118
119         if (c > 0) {
120                 /* Stuff the data into the input queue of the other end */
121                 c = tty_insert_flip_string(to, buf, c);
122                 /* And shovel */
123                 if (c) {
124                         tty_flip_buffer_push(to);
125                         tty_wakeup(tty);
126                 }
127         }
128         return c;
129 }
130
131 /**
132  *      pty_write_room  -       write space
133  *      @tty: tty we are writing from
134  *
135  *      Report how many bytes the ldisc can send into the queue for
136  *      the other device.
137  */
138
139 static int pty_write_room(struct tty_struct *tty)
140 {
141         if (tty->stopped)
142                 return 0;
143         return pty_space(tty->link);
144 }
145
146 /**
147  *      pty_chars_in_buffer     -       characters currently in our tx queue
148  *      @tty: our tty
149  *
150  *      Report how much we have in the transmit queue. As everything is
151  *      instantly at the other end this is easy to implement.
152  */
153
154 static int pty_chars_in_buffer(struct tty_struct *tty)
155 {
156         return 0;
157 }
158
159 /* Set the lock flag on a pty */
160 static int pty_set_lock(struct tty_struct *tty, int __user *arg)
161 {
162         int val;
163         if (get_user(val, arg))
164                 return -EFAULT;
165         if (val)
166                 set_bit(TTY_PTY_LOCK, &tty->flags);
167         else
168                 clear_bit(TTY_PTY_LOCK, &tty->flags);
169         return 0;
170 }
171
172 static void pty_flush_buffer(struct tty_struct *tty)
173 {
174         struct tty_struct *to = tty->link;
175         unsigned long flags;
176
177         if (!to)
178                 return;
179         /* tty_buffer_flush(to); FIXME */
180         if (to->packet) {
181                 spin_lock_irqsave(&tty->ctrl_lock, flags);
182                 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
183                 wake_up_interruptible(&to->read_wait);
184                 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
185         }
186 }
187
188 static int pty_open(struct tty_struct *tty, struct file *filp)
189 {
190         int     retval = -ENODEV;
191
192         if (!tty || !tty->link)
193                 goto out;
194
195         retval = -EIO;
196         if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
197                 goto out;
198         if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
199                 goto out;
200         if (tty->link->count != 1)
201                 goto out;
202
203         clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
204         set_bit(TTY_THROTTLED, &tty->flags);
205         retval = 0;
206 out:
207         return retval;
208 }
209
210 static void pty_set_termios(struct tty_struct *tty,
211                                         struct ktermios *old_termios)
212 {
213         tty->termios->c_cflag &= ~(CSIZE | PARENB);
214         tty->termios->c_cflag |= (CS8 | CREAD);
215 }
216
217 /**
218  *      pty_do_resize           -       resize event
219  *      @tty: tty being resized
220  *      @ws: window size being set.
221  *
222  *      Update the termios variables and send the neccessary signals to
223  *      peform a terminal resize correctly
224  */
225
226 int pty_resize(struct tty_struct *tty,  struct winsize *ws)
227 {
228         struct pid *pgrp, *rpgrp;
229         unsigned long flags;
230         struct tty_struct *pty = tty->link;
231
232         /* For a PTY we need to lock the tty side */
233         mutex_lock(&tty->termios_mutex);
234         if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
235                 goto done;
236
237         /* Get the PID values and reference them so we can
238            avoid holding the tty ctrl lock while sending signals.
239            We need to lock these individually however. */
240
241         spin_lock_irqsave(&tty->ctrl_lock, flags);
242         pgrp = get_pid(tty->pgrp);
243         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
244
245         spin_lock_irqsave(&pty->ctrl_lock, flags);
246         rpgrp = get_pid(pty->pgrp);
247         spin_unlock_irqrestore(&pty->ctrl_lock, flags);
248
249         if (pgrp)
250                 kill_pgrp(pgrp, SIGWINCH, 1);
251         if (rpgrp != pgrp && rpgrp)
252                 kill_pgrp(rpgrp, SIGWINCH, 1);
253
254         put_pid(pgrp);
255         put_pid(rpgrp);
256
257         tty->winsize = *ws;
258         pty->winsize = *ws;     /* Never used so will go away soon */
259 done:
260         mutex_unlock(&tty->termios_mutex);
261         return 0;
262 }
263
264 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
265 {
266         struct tty_struct *o_tty;
267         int idx = tty->index;
268         int retval;
269
270         o_tty = alloc_tty_struct();
271         if (!o_tty)
272                 return -ENOMEM;
273         if (!try_module_get(driver->other->owner)) {
274                 /* This cannot in fact currently happen */
275                 free_tty_struct(o_tty);
276                 return -ENOMEM;
277         }
278         initialize_tty_struct(o_tty, driver->other, idx);
279
280         /* We always use new tty termios data so we can do this
281            the easy way .. */
282         retval = tty_init_termios(tty);
283         if (retval)
284                 goto free_mem_out;
285
286         retval = tty_init_termios(o_tty);
287         if (retval) {
288                 tty_free_termios(tty);
289                 goto free_mem_out;
290         }
291
292         /*
293          * Everything allocated ... set up the o_tty structure.
294          */
295         driver->other->ttys[idx] = o_tty;
296         tty_driver_kref_get(driver->other);
297         if (driver->subtype == PTY_TYPE_MASTER)
298                 o_tty->count++;
299         /* Establish the links in both directions */
300         tty->link   = o_tty;
301         o_tty->link = tty;
302
303         tty_driver_kref_get(driver);
304         tty->count++;
305         driver->ttys[idx] = tty;
306         return 0;
307 free_mem_out:
308         module_put(o_tty->driver->owner);
309         free_tty_struct(o_tty);
310         return -ENOMEM;
311 }
312
313
314 static const struct tty_operations pty_ops = {
315         .install = pty_install,
316         .open = pty_open,
317         .close = pty_close,
318         .write = pty_write,
319         .write_room = pty_write_room,
320         .flush_buffer = pty_flush_buffer,
321         .chars_in_buffer = pty_chars_in_buffer,
322         .unthrottle = pty_unthrottle,
323         .set_termios = pty_set_termios,
324         .resize = pty_resize
325 };
326
327 /* Traditional BSD devices */
328 #ifdef CONFIG_LEGACY_PTYS
329 static struct tty_driver *pty_driver, *pty_slave_driver;
330
331 static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
332                          unsigned int cmd, unsigned long arg)
333 {
334         switch (cmd) {
335         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
336                 return pty_set_lock(tty, (int __user *) arg);
337         }
338         return -ENOIOCTLCMD;
339 }
340
341 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
342 module_param(legacy_count, int, 0);
343
344 static const struct tty_operations pty_ops_bsd = {
345         .open = pty_open,
346         .close = pty_close,
347         .write = pty_write,
348         .write_room = pty_write_room,
349         .flush_buffer = pty_flush_buffer,
350         .chars_in_buffer = pty_chars_in_buffer,
351         .unthrottle = pty_unthrottle,
352         .set_termios = pty_set_termios,
353         .ioctl = pty_bsd_ioctl,
354         .resize = pty_resize
355 };
356
357 static void __init legacy_pty_init(void)
358 {
359         if (legacy_count <= 0)
360                 return;
361
362         pty_driver = alloc_tty_driver(legacy_count);
363         if (!pty_driver)
364                 panic("Couldn't allocate pty driver");
365
366         pty_slave_driver = alloc_tty_driver(legacy_count);
367         if (!pty_slave_driver)
368                 panic("Couldn't allocate pty slave driver");
369
370         pty_driver->owner = THIS_MODULE;
371         pty_driver->driver_name = "pty_master";
372         pty_driver->name = "pty";
373         pty_driver->major = PTY_MASTER_MAJOR;
374         pty_driver->minor_start = 0;
375         pty_driver->type = TTY_DRIVER_TYPE_PTY;
376         pty_driver->subtype = PTY_TYPE_MASTER;
377         pty_driver->init_termios = tty_std_termios;
378         pty_driver->init_termios.c_iflag = 0;
379         pty_driver->init_termios.c_oflag = 0;
380         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
381         pty_driver->init_termios.c_lflag = 0;
382         pty_driver->init_termios.c_ispeed = 38400;
383         pty_driver->init_termios.c_ospeed = 38400;
384         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
385         pty_driver->other = pty_slave_driver;
386         tty_set_operations(pty_driver, &pty_ops);
387
388         pty_slave_driver->owner = THIS_MODULE;
389         pty_slave_driver->driver_name = "pty_slave";
390         pty_slave_driver->name = "ttyp";
391         pty_slave_driver->major = PTY_SLAVE_MAJOR;
392         pty_slave_driver->minor_start = 0;
393         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
394         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
395         pty_slave_driver->init_termios = tty_std_termios;
396         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
397         pty_slave_driver->init_termios.c_ispeed = 38400;
398         pty_slave_driver->init_termios.c_ospeed = 38400;
399         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
400                                         TTY_DRIVER_REAL_RAW;
401         pty_slave_driver->other = pty_driver;
402         tty_set_operations(pty_slave_driver, &pty_ops);
403
404         if (tty_register_driver(pty_driver))
405                 panic("Couldn't register pty driver");
406         if (tty_register_driver(pty_slave_driver))
407                 panic("Couldn't register pty slave driver");
408 }
409 #else
410 static inline void legacy_pty_init(void) { }
411 #endif
412
413 /* Unix98 devices */
414 #ifdef CONFIG_UNIX98_PTYS
415 /*
416  * sysctl support for setting limits on the number of Unix98 ptys allocated.
417  * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
418  */
419 int pty_limit = NR_UNIX98_PTY_DEFAULT;
420 static int pty_limit_min;
421 static int pty_limit_max = NR_UNIX98_PTY_MAX;
422 static int pty_count;
423
424 static struct cdev ptmx_cdev;
425
426 static struct ctl_table pty_table[] = {
427         {
428                 .ctl_name       = PTY_MAX,
429                 .procname       = "max",
430                 .maxlen         = sizeof(int),
431                 .mode           = 0644,
432                 .data           = &pty_limit,
433                 .proc_handler   = &proc_dointvec_minmax,
434                 .strategy       = &sysctl_intvec,
435                 .extra1         = &pty_limit_min,
436                 .extra2         = &pty_limit_max,
437         }, {
438                 .ctl_name       = PTY_NR,
439                 .procname       = "nr",
440                 .maxlen         = sizeof(int),
441                 .mode           = 0444,
442                 .data           = &pty_count,
443                 .proc_handler   = &proc_dointvec,
444         }, {
445                 .ctl_name       = 0
446         }
447 };
448
449 static struct ctl_table pty_kern_table[] = {
450         {
451                 .ctl_name       = KERN_PTY,
452                 .procname       = "pty",
453                 .mode           = 0555,
454                 .child          = pty_table,
455         },
456         {}
457 };
458
459 static struct ctl_table pty_root_table[] = {
460         {
461                 .ctl_name       = CTL_KERN,
462                 .procname       = "kernel",
463                 .mode           = 0555,
464                 .child          = pty_kern_table,
465         },
466         {}
467 };
468
469
470 static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
471                             unsigned int cmd, unsigned long arg)
472 {
473         switch (cmd) {
474         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
475                 return pty_set_lock(tty, (int __user *)arg);
476         case TIOCGPTN: /* Get PT Number */
477                 return put_user(tty->index, (unsigned int __user *)arg);
478         }
479
480         return -ENOIOCTLCMD;
481 }
482
483 /**
484  *      ptm_unix98_lookup       -       find a pty master
485  *      @driver: ptm driver
486  *      @idx: tty index
487  *
488  *      Look up a pty master device. Called under the tty_mutex for now.
489  *      This provides our locking.
490  */
491
492 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
493                 struct inode *ptm_inode, int idx)
494 {
495         struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
496         if (tty)
497                 tty = tty->link;
498         return tty;
499 }
500
501 /**
502  *      pts_unix98_lookup       -       find a pty slave
503  *      @driver: pts driver
504  *      @idx: tty index
505  *
506  *      Look up a pty master device. Called under the tty_mutex for now.
507  *      This provides our locking.
508  */
509
510 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
511                 struct inode *pts_inode, int idx)
512 {
513         struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
514         /* Master must be open before slave */
515         if (!tty)
516                 return ERR_PTR(-EIO);
517         return tty;
518 }
519
520 static void pty_unix98_shutdown(struct tty_struct *tty)
521 {
522         /* We have our own method as we don't use the tty index */
523         kfree(tty->termios);
524 }
525
526 /* We have no need to install and remove our tty objects as devpts does all
527    the work for us */
528
529 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
530 {
531         struct tty_struct *o_tty;
532         int idx = tty->index;
533
534         o_tty = alloc_tty_struct();
535         if (!o_tty)
536                 return -ENOMEM;
537         if (!try_module_get(driver->other->owner)) {
538                 /* This cannot in fact currently happen */
539                 free_tty_struct(o_tty);
540                 return -ENOMEM;
541         }
542         initialize_tty_struct(o_tty, driver->other, idx);
543
544         tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
545         if (tty->termios == NULL)
546                 goto free_mem_out;
547         *tty->termios = driver->init_termios;
548         tty->termios_locked = tty->termios + 1;
549
550         o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
551         if (o_tty->termios == NULL)
552                 goto free_mem_out;
553         *o_tty->termios = driver->other->init_termios;
554         o_tty->termios_locked = o_tty->termios + 1;
555
556         tty_driver_kref_get(driver->other);
557         if (driver->subtype == PTY_TYPE_MASTER)
558                 o_tty->count++;
559         /* Establish the links in both directions */
560         tty->link   = o_tty;
561         o_tty->link = tty;
562         /*
563          * All structures have been allocated, so now we install them.
564          * Failures after this point use release_tty to clean up, so
565          * there's no need to null out the local pointers.
566          */
567         tty_driver_kref_get(driver);
568         tty->count++;
569         pty_count++;
570         return 0;
571 free_mem_out:
572         kfree(o_tty->termios);
573         module_put(o_tty->driver->owner);
574         free_tty_struct(o_tty);
575         kfree(tty->termios);
576         return -ENOMEM;
577 }
578
579 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
580 {
581         pty_count--;
582 }
583
584 static const struct tty_operations ptm_unix98_ops = {
585         .lookup = ptm_unix98_lookup,
586         .install = pty_unix98_install,
587         .remove = pty_unix98_remove,
588         .open = pty_open,
589         .close = pty_close,
590         .write = pty_write,
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         .ioctl = pty_unix98_ioctl,
597         .shutdown = pty_unix98_shutdown,
598         .resize = pty_resize
599 };
600
601 static const struct tty_operations pty_unix98_ops = {
602         .lookup = pts_unix98_lookup,
603         .install = pty_unix98_install,
604         .remove = pty_unix98_remove,
605         .open = pty_open,
606         .close = pty_close,
607         .write = pty_write,
608         .write_room = pty_write_room,
609         .flush_buffer = pty_flush_buffer,
610         .chars_in_buffer = pty_chars_in_buffer,
611         .unthrottle = pty_unthrottle,
612         .set_termios = pty_set_termios,
613         .shutdown = pty_unix98_shutdown
614 };
615
616 /**
617  *      ptmx_open               -       open a unix 98 pty master
618  *      @inode: inode of device file
619  *      @filp: file pointer to tty
620  *
621  *      Allocate a unix98 pty master device from the ptmx driver.
622  *
623  *      Locking: tty_mutex protects the init_dev work. tty->count should
624  *              protect the rest.
625  *              allocated_ptys_lock handles the list of free pty numbers
626  */
627
628 static int __ptmx_open(struct inode *inode, struct file *filp)
629 {
630         struct tty_struct *tty;
631         int retval;
632         int index;
633
634         nonseekable_open(inode, filp);
635
636         /* find a device that is not in use. */
637         index = devpts_new_index(inode);
638         if (index < 0)
639                 return index;
640
641         mutex_lock(&tty_mutex);
642         tty = tty_init_dev(ptm_driver, index, 1);
643         mutex_unlock(&tty_mutex);
644
645         if (IS_ERR(tty)) {
646                 retval = PTR_ERR(tty);
647                 goto out;
648         }
649
650         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
651         filp->private_data = tty;
652         file_move(filp, &tty->tty_files);
653
654         retval = devpts_pty_new(inode, tty->link);
655         if (retval)
656                 goto out1;
657
658         retval = ptm_driver->ops->open(tty, filp);
659         if (!retval)
660                 return 0;
661 out1:
662         tty_release_dev(filp);
663         return retval;
664 out:
665         devpts_kill_index(inode, index);
666         return retval;
667 }
668
669 static int ptmx_open(struct inode *inode, struct file *filp)
670 {
671         int ret;
672
673         lock_kernel();
674         ret = __ptmx_open(inode, filp);
675         unlock_kernel();
676         return ret;
677 }
678
679 static struct file_operations ptmx_fops;
680
681 static void __init unix98_pty_init(void)
682 {
683         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
684         if (!ptm_driver)
685                 panic("Couldn't allocate Unix98 ptm driver");
686         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
687         if (!pts_driver)
688                 panic("Couldn't allocate Unix98 pts driver");
689
690         ptm_driver->owner = THIS_MODULE;
691         ptm_driver->driver_name = "pty_master";
692         ptm_driver->name = "ptm";
693         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
694         ptm_driver->minor_start = 0;
695         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
696         ptm_driver->subtype = PTY_TYPE_MASTER;
697         ptm_driver->init_termios = tty_std_termios;
698         ptm_driver->init_termios.c_iflag = 0;
699         ptm_driver->init_termios.c_oflag = 0;
700         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
701         ptm_driver->init_termios.c_lflag = 0;
702         ptm_driver->init_termios.c_ispeed = 38400;
703         ptm_driver->init_termios.c_ospeed = 38400;
704         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
705                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
706         ptm_driver->other = pts_driver;
707         tty_set_operations(ptm_driver, &ptm_unix98_ops);
708
709         pts_driver->owner = THIS_MODULE;
710         pts_driver->driver_name = "pty_slave";
711         pts_driver->name = "pts";
712         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
713         pts_driver->minor_start = 0;
714         pts_driver->type = TTY_DRIVER_TYPE_PTY;
715         pts_driver->subtype = PTY_TYPE_SLAVE;
716         pts_driver->init_termios = tty_std_termios;
717         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
718         pts_driver->init_termios.c_ispeed = 38400;
719         pts_driver->init_termios.c_ospeed = 38400;
720         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
721                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
722         pts_driver->other = ptm_driver;
723         tty_set_operations(pts_driver, &pty_unix98_ops);
724
725         if (tty_register_driver(ptm_driver))
726                 panic("Couldn't register Unix98 ptm driver");
727         if (tty_register_driver(pts_driver))
728                 panic("Couldn't register Unix98 pts driver");
729
730         register_sysctl_table(pty_root_table);
731
732         /* Now create the /dev/ptmx special device */
733         tty_default_fops(&ptmx_fops);
734         ptmx_fops.open = ptmx_open;
735
736         cdev_init(&ptmx_cdev, &ptmx_fops);
737         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
738             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
739                 panic("Couldn't register /dev/ptmx driver\n");
740         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
741 }
742
743 #else
744 static inline void unix98_pty_init(void) { }
745 #endif
746
747 static int __init pty_init(void)
748 {
749         legacy_pty_init();
750         unix98_pty_init();
751         return 0;
752 }
753 module_init(pty_init);