Merge branch 'linus' into core/iommu
[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  *
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/sysctl.h>
26 #include <linux/device.h>
27 #include <linux/uaccess.h>
28 #include <linux/bitops.h>
29 #include <linux/devpts_fs.h>
30
31 #include <asm/system.h>
32
33 /* These are global because they are accessed in tty_io.c */
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         struct tty_struct *o_tty = tty->link;
80
81         if (!o_tty)
82                 return;
83
84         tty_wakeup(o_tty);
85         set_bit(TTY_THROTTLED, &tty->flags);
86 }
87
88 /*
89  * WSH 05/24/97: modified to
90  *   (1) use space in tty->flip instead of a shared temp buffer
91  *       The flip buffers aren't being used for a pty, so there's lots
92  *       of space available.  The buffer is protected by a per-pty
93  *       semaphore that should almost never come under contention.
94  *   (2) avoid redundant copying for cases where count >> receive_room
95  * N.B. Calls from user space may now return an error code instead of
96  * a count.
97  *
98  * FIXME: Our pty_write method is called with our ldisc lock held but
99  * not our partners. We can't just take the other one blindly without
100  * risking deadlocks.
101  */
102 static int pty_write(struct tty_struct *tty, const unsigned char *buf,
103                                                                 int count)
104 {
105         struct tty_struct *to = tty->link;
106         int     c;
107
108         if (!to || tty->stopped)
109                 return 0;
110
111         c = to->receive_room;
112         if (c > count)
113                 c = count;
114         to->ldisc.ops->receive_buf(to, buf, NULL, c);
115
116         return c;
117 }
118
119 static int pty_write_room(struct tty_struct *tty)
120 {
121         struct tty_struct *to = tty->link;
122
123         if (!to || tty->stopped)
124                 return 0;
125
126         return to->receive_room;
127 }
128
129 /*
130  *      WSH 05/24/97:  Modified for asymmetric MASTER/SLAVE behavior
131  *      The chars_in_buffer() value is used by the ldisc select() function
132  *      to hold off writing when chars_in_buffer > WAKEUP_CHARS (== 256).
133  *      The pty driver chars_in_buffer() Master/Slave must behave differently:
134  *
135  *      The Master side needs to allow typed-ahead commands to accumulate
136  *      while being canonicalized, so we report "our buffer" as empty until
137  *      some threshold is reached, and then report the count. (Any count >
138  *      WAKEUP_CHARS is regarded by select() as "full".)  To avoid deadlock
139  *      the count returned must be 0 if no canonical data is available to be
140  *      read. (The N_TTY ldisc.chars_in_buffer now knows this.)
141  *
142  *      The Slave side passes all characters in raw mode to the Master side's
143  *      buffer where they can be read immediately, so in this case we can
144  *      return the true count in the buffer.
145  */
146 static int pty_chars_in_buffer(struct tty_struct *tty)
147 {
148         struct tty_struct *to = tty->link;
149         int count;
150
151         /* We should get the line discipline lock for "tty->link" */
152         if (!to || !to->ldisc.ops->chars_in_buffer)
153                 return 0;
154
155         /* The ldisc must report 0 if no characters available to be read */
156         count = to->ldisc.ops->chars_in_buffer(to);
157
158         if (tty->driver->subtype == PTY_TYPE_SLAVE)
159                 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         retval = 0;
219 out:
220         return retval;
221 }
222
223 static void pty_set_termios(struct tty_struct *tty,
224                                         struct ktermios *old_termios)
225 {
226         tty->termios->c_cflag &= ~(CSIZE | PARENB);
227         tty->termios->c_cflag |= (CS8 | CREAD);
228 }
229
230 /**
231  *      pty_do_resize           -       resize event
232  *      @tty: tty being resized
233  *      @ws: window size being set.
234  *
235  *      Update the termios variables and send the neccessary signals to
236  *      peform a terminal resize correctly
237  */
238
239 int pty_resize(struct tty_struct *tty,  struct winsize *ws)
240 {
241         struct pid *pgrp, *rpgrp;
242         unsigned long flags;
243         struct tty_struct *pty = tty->link;
244
245         /* For a PTY we need to lock the tty side */
246         mutex_lock(&tty->termios_mutex);
247         if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
248                 goto done;
249
250         /* Get the PID values and reference them so we can
251            avoid holding the tty ctrl lock while sending signals.
252            We need to lock these individually however. */
253
254         spin_lock_irqsave(&tty->ctrl_lock, flags);
255         pgrp = get_pid(tty->pgrp);
256         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
257
258         spin_lock_irqsave(&pty->ctrl_lock, flags);
259         rpgrp = get_pid(pty->pgrp);
260         spin_unlock_irqrestore(&pty->ctrl_lock, flags);
261
262         if (pgrp)
263                 kill_pgrp(pgrp, SIGWINCH, 1);
264         if (rpgrp != pgrp && rpgrp)
265                 kill_pgrp(rpgrp, SIGWINCH, 1);
266
267         put_pid(pgrp);
268         put_pid(rpgrp);
269
270         tty->winsize = *ws;
271         pty->winsize = *ws;     /* Never used so will go away soon */
272 done:
273         mutex_unlock(&tty->termios_mutex);
274         return 0;
275 }
276
277 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
278 {
279         struct tty_struct *o_tty;
280         int idx = tty->index;
281         int retval;
282
283         o_tty = alloc_tty_struct();
284         if (!o_tty)
285                 return -ENOMEM;
286         if (!try_module_get(driver->other->owner)) {
287                 /* This cannot in fact currently happen */
288                 free_tty_struct(o_tty);
289                 return -ENOMEM;
290         }
291         initialize_tty_struct(o_tty, driver->other, idx);
292
293         /* We always use new tty termios data so we can do this
294            the easy way .. */
295         retval = tty_init_termios(tty);
296         if (retval)
297                 goto free_mem_out;
298
299         retval = tty_init_termios(o_tty);
300         if (retval) {
301                 tty_free_termios(tty);
302                 goto free_mem_out;
303         }
304
305         /*
306          * Everything allocated ... set up the o_tty structure.
307          */
308         driver->other->ttys[idx] = o_tty;
309         tty_driver_kref_get(driver->other);
310         if (driver->subtype == PTY_TYPE_MASTER)
311                 o_tty->count++;
312         /* Establish the links in both directions */
313         tty->link   = o_tty;
314         o_tty->link = tty;
315
316         tty_driver_kref_get(driver);
317         tty->count++;
318         driver->ttys[idx] = tty;
319         return 0;
320 free_mem_out:
321         module_put(o_tty->driver->owner);
322         free_tty_struct(o_tty);
323         return -ENOMEM;
324 }
325
326
327 static const struct tty_operations pty_ops = {
328         .install = pty_install,
329         .open = pty_open,
330         .close = pty_close,
331         .write = pty_write,
332         .write_room = pty_write_room,
333         .flush_buffer = pty_flush_buffer,
334         .chars_in_buffer = pty_chars_in_buffer,
335         .unthrottle = pty_unthrottle,
336         .set_termios = pty_set_termios,
337         .resize = pty_resize
338 };
339
340 /* Traditional BSD devices */
341 #ifdef CONFIG_LEGACY_PTYS
342 static struct tty_driver *pty_driver, *pty_slave_driver;
343
344 static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
345                          unsigned int cmd, unsigned long arg)
346 {
347         switch (cmd) {
348         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
349                 return pty_set_lock(tty, (int __user *) arg);
350         }
351         return -ENOIOCTLCMD;
352 }
353
354 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
355 module_param(legacy_count, int, 0);
356
357 static const struct tty_operations pty_ops_bsd = {
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
368 };
369
370 static void __init legacy_pty_init(void)
371 {
372         if (legacy_count <= 0)
373                 return;
374
375         pty_driver = alloc_tty_driver(legacy_count);
376         if (!pty_driver)
377                 panic("Couldn't allocate pty driver");
378
379         pty_slave_driver = alloc_tty_driver(legacy_count);
380         if (!pty_slave_driver)
381                 panic("Couldn't allocate pty slave driver");
382
383         pty_driver->owner = THIS_MODULE;
384         pty_driver->driver_name = "pty_master";
385         pty_driver->name = "pty";
386         pty_driver->major = PTY_MASTER_MAJOR;
387         pty_driver->minor_start = 0;
388         pty_driver->type = TTY_DRIVER_TYPE_PTY;
389         pty_driver->subtype = PTY_TYPE_MASTER;
390         pty_driver->init_termios = tty_std_termios;
391         pty_driver->init_termios.c_iflag = 0;
392         pty_driver->init_termios.c_oflag = 0;
393         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
394         pty_driver->init_termios.c_lflag = 0;
395         pty_driver->init_termios.c_ispeed = 38400;
396         pty_driver->init_termios.c_ospeed = 38400;
397         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
398         pty_driver->other = pty_slave_driver;
399         tty_set_operations(pty_driver, &pty_ops);
400
401         pty_slave_driver->owner = THIS_MODULE;
402         pty_slave_driver->driver_name = "pty_slave";
403         pty_slave_driver->name = "ttyp";
404         pty_slave_driver->major = PTY_SLAVE_MAJOR;
405         pty_slave_driver->minor_start = 0;
406         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
407         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
408         pty_slave_driver->init_termios = tty_std_termios;
409         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
410         pty_slave_driver->init_termios.c_ispeed = 38400;
411         pty_slave_driver->init_termios.c_ospeed = 38400;
412         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
413                                         TTY_DRIVER_REAL_RAW;
414         pty_slave_driver->other = pty_driver;
415         tty_set_operations(pty_slave_driver, &pty_ops);
416
417         if (tty_register_driver(pty_driver))
418                 panic("Couldn't register pty driver");
419         if (tty_register_driver(pty_slave_driver))
420                 panic("Couldn't register pty slave driver");
421 }
422 #else
423 static inline void legacy_pty_init(void) { }
424 #endif
425
426 /* Unix98 devices */
427 #ifdef CONFIG_UNIX98_PTYS
428 /*
429  * sysctl support for setting limits on the number of Unix98 ptys allocated.
430  * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
431  */
432 int pty_limit = NR_UNIX98_PTY_DEFAULT;
433 static int pty_limit_min;
434 static int pty_limit_max = NR_UNIX98_PTY_MAX;
435 static int pty_count;
436
437 static struct cdev ptmx_cdev;
438
439 static struct ctl_table pty_table[] = {
440         {
441                 .ctl_name       = PTY_MAX,
442                 .procname       = "max",
443                 .maxlen         = sizeof(int),
444                 .mode           = 0644,
445                 .data           = &pty_limit,
446                 .proc_handler   = &proc_dointvec_minmax,
447                 .strategy       = &sysctl_intvec,
448                 .extra1         = &pty_limit_min,
449                 .extra2         = &pty_limit_max,
450         }, {
451                 .ctl_name       = PTY_NR,
452                 .procname       = "nr",
453                 .maxlen         = sizeof(int),
454                 .mode           = 0444,
455                 .data           = &pty_count,
456                 .proc_handler   = &proc_dointvec,
457         }, {
458                 .ctl_name       = 0
459         }
460 };
461
462 static struct ctl_table pty_kern_table[] = {
463         {
464                 .ctl_name       = KERN_PTY,
465                 .procname       = "pty",
466                 .mode           = 0555,
467                 .child          = pty_table,
468         },
469         {}
470 };
471
472 static struct ctl_table pty_root_table[] = {
473         {
474                 .ctl_name       = CTL_KERN,
475                 .procname       = "kernel",
476                 .mode           = 0555,
477                 .child          = pty_kern_table,
478         },
479         {}
480 };
481
482
483 static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
484                             unsigned int cmd, unsigned long arg)
485 {
486         switch (cmd) {
487         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
488                 return pty_set_lock(tty, (int __user *)arg);
489         case TIOCGPTN: /* Get PT Number */
490                 return put_user(tty->index, (unsigned int __user *)arg);
491         }
492
493         return -ENOIOCTLCMD;
494 }
495
496 /**
497  *      ptm_unix98_lookup       -       find a pty master
498  *      @driver: ptm driver
499  *      @idx: tty index
500  *
501  *      Look up a pty master device. Called under the tty_mutex for now.
502  *      This provides our locking.
503  */
504
505 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
506                 struct inode *ptm_inode, int idx)
507 {
508         struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
509         if (tty)
510                 tty = tty->link;
511         return tty;
512 }
513
514 /**
515  *      pts_unix98_lookup       -       find a pty slave
516  *      @driver: pts driver
517  *      @idx: tty index
518  *
519  *      Look up a pty master device. Called under the tty_mutex for now.
520  *      This provides our locking.
521  */
522
523 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
524                 struct inode *pts_inode, int idx)
525 {
526         struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
527         /* Master must be open before slave */
528         if (!tty)
529                 return ERR_PTR(-EIO);
530         return tty;
531 }
532
533 static void pty_unix98_shutdown(struct tty_struct *tty)
534 {
535         /* We have our own method as we don't use the tty index */
536         kfree(tty->termios);
537 }
538
539 /* We have no need to install and remove our tty objects as devpts does all
540    the work for us */
541
542 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
543 {
544         struct tty_struct *o_tty;
545         int idx = tty->index;
546
547         o_tty = alloc_tty_struct();
548         if (!o_tty)
549                 return -ENOMEM;
550         if (!try_module_get(driver->other->owner)) {
551                 /* This cannot in fact currently happen */
552                 free_tty_struct(o_tty);
553                 return -ENOMEM;
554         }
555         initialize_tty_struct(o_tty, driver->other, idx);
556
557         tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
558         if (tty->termios == NULL)
559                 goto free_mem_out;
560         *tty->termios = driver->init_termios;
561         tty->termios_locked = tty->termios + 1;
562
563         o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
564         if (o_tty->termios == NULL)
565                 goto free_mem_out;
566         *o_tty->termios = driver->other->init_termios;
567         o_tty->termios_locked = o_tty->termios + 1;
568
569         tty_driver_kref_get(driver->other);
570         if (driver->subtype == PTY_TYPE_MASTER)
571                 o_tty->count++;
572         /* Establish the links in both directions */
573         tty->link   = o_tty;
574         o_tty->link = tty;
575         /*
576          * All structures have been allocated, so now we install them.
577          * Failures after this point use release_tty to clean up, so
578          * there's no need to null out the local pointers.
579          */
580         tty_driver_kref_get(driver);
581         tty->count++;
582         pty_count++;
583         return 0;
584 free_mem_out:
585         kfree(o_tty->termios);
586         module_put(o_tty->driver->owner);
587         free_tty_struct(o_tty);
588         kfree(tty->termios);
589         return -ENOMEM;
590 }
591
592 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
593 {
594         pty_count--;
595 }
596
597 static const struct tty_operations ptm_unix98_ops = {
598         .lookup = ptm_unix98_lookup,
599         .install = pty_unix98_install,
600         .remove = pty_unix98_remove,
601         .open = pty_open,
602         .close = pty_close,
603         .write = pty_write,
604         .write_room = pty_write_room,
605         .flush_buffer = pty_flush_buffer,
606         .chars_in_buffer = pty_chars_in_buffer,
607         .unthrottle = pty_unthrottle,
608         .set_termios = pty_set_termios,
609         .ioctl = pty_unix98_ioctl,
610         .shutdown = pty_unix98_shutdown,
611         .resize = pty_resize
612 };
613
614 static const struct tty_operations pty_unix98_ops = {
615         .lookup = pts_unix98_lookup,
616         .install = pty_unix98_install,
617         .remove = pty_unix98_remove,
618         .open = pty_open,
619         .close = pty_close,
620         .write = pty_write,
621         .write_room = pty_write_room,
622         .flush_buffer = pty_flush_buffer,
623         .chars_in_buffer = pty_chars_in_buffer,
624         .unthrottle = pty_unthrottle,
625         .set_termios = pty_set_termios,
626         .shutdown = pty_unix98_shutdown
627 };
628
629 /**
630  *      ptmx_open               -       open a unix 98 pty master
631  *      @inode: inode of device file
632  *      @filp: file pointer to tty
633  *
634  *      Allocate a unix98 pty master device from the ptmx driver.
635  *
636  *      Locking: tty_mutex protects the init_dev work. tty->count should
637  *              protect the rest.
638  *              allocated_ptys_lock handles the list of free pty numbers
639  */
640
641 static int __ptmx_open(struct inode *inode, struct file *filp)
642 {
643         struct tty_struct *tty;
644         int retval;
645         int index;
646
647         nonseekable_open(inode, filp);
648
649         /* find a device that is not in use. */
650         index = devpts_new_index(inode);
651         if (index < 0)
652                 return index;
653
654         mutex_lock(&tty_mutex);
655         tty = tty_init_dev(ptm_driver, index, 1);
656         mutex_unlock(&tty_mutex);
657
658         if (IS_ERR(tty)) {
659                 retval = PTR_ERR(tty);
660                 goto out;
661         }
662
663         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
664         filp->private_data = tty;
665         file_move(filp, &tty->tty_files);
666
667         retval = devpts_pty_new(inode, tty->link);
668         if (retval)
669                 goto out1;
670
671         retval = ptm_driver->ops->open(tty, filp);
672         if (!retval)
673                 return 0;
674 out1:
675         tty_release_dev(filp);
676         return retval;
677 out:
678         devpts_kill_index(inode, index);
679         return retval;
680 }
681
682 static int ptmx_open(struct inode *inode, struct file *filp)
683 {
684         int ret;
685
686         lock_kernel();
687         ret = __ptmx_open(inode, filp);
688         unlock_kernel();
689         return ret;
690 }
691
692 static struct file_operations ptmx_fops;
693
694 static void __init unix98_pty_init(void)
695 {
696         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
697         if (!ptm_driver)
698                 panic("Couldn't allocate Unix98 ptm driver");
699         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
700         if (!pts_driver)
701                 panic("Couldn't allocate Unix98 pts driver");
702
703         ptm_driver->owner = THIS_MODULE;
704         ptm_driver->driver_name = "pty_master";
705         ptm_driver->name = "ptm";
706         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
707         ptm_driver->minor_start = 0;
708         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
709         ptm_driver->subtype = PTY_TYPE_MASTER;
710         ptm_driver->init_termios = tty_std_termios;
711         ptm_driver->init_termios.c_iflag = 0;
712         ptm_driver->init_termios.c_oflag = 0;
713         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
714         ptm_driver->init_termios.c_lflag = 0;
715         ptm_driver->init_termios.c_ispeed = 38400;
716         ptm_driver->init_termios.c_ospeed = 38400;
717         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
718                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
719         ptm_driver->other = pts_driver;
720         tty_set_operations(ptm_driver, &ptm_unix98_ops);
721
722         pts_driver->owner = THIS_MODULE;
723         pts_driver->driver_name = "pty_slave";
724         pts_driver->name = "pts";
725         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
726         pts_driver->minor_start = 0;
727         pts_driver->type = TTY_DRIVER_TYPE_PTY;
728         pts_driver->subtype = PTY_TYPE_SLAVE;
729         pts_driver->init_termios = tty_std_termios;
730         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
731         pts_driver->init_termios.c_ispeed = 38400;
732         pts_driver->init_termios.c_ospeed = 38400;
733         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
734                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
735         pts_driver->other = ptm_driver;
736         tty_set_operations(pts_driver, &pty_unix98_ops);
737
738         if (tty_register_driver(ptm_driver))
739                 panic("Couldn't register Unix98 ptm driver");
740         if (tty_register_driver(pts_driver))
741                 panic("Couldn't register Unix98 pts driver");
742
743         register_sysctl_table(pty_root_table);
744
745         /* Now create the /dev/ptmx special device */
746         tty_default_fops(&ptmx_fops);
747         ptmx_fops.open = ptmx_open;
748
749         cdev_init(&ptmx_cdev, &ptmx_fops);
750         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
751             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
752                 panic("Couldn't register /dev/ptmx driver\n");
753         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
754 }
755
756 #else
757 static inline void unix98_pty_init(void) { }
758 #endif
759
760 static int __init pty_init(void)
761 {
762         legacy_pty_init();
763         unix98_pty_init();
764         return 0;
765 }
766 module_init(pty_init);