Merge branch 'linus' into test
[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  *  When reading this code see also fs/devpts. In particular note that the
12  *  driver_data field is used by the devpts side as a binding to the devpts
13  *  inode.
14  */
15
16 #include <linux/module.h>
17
18 #include <linux/errno.h>
19 #include <linux/interrupt.h>
20 #include <linux/tty.h>
21 #include <linux/tty_flip.h>
22 #include <linux/fcntl.h>
23 #include <linux/string.h>
24 #include <linux/major.h>
25 #include <linux/mm.h>
26 #include <linux/init.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
33 #include <asm/system.h>
34
35 /* These are global because they are accessed in tty_io.c */
36 #ifdef CONFIG_UNIX98_PTYS
37 struct tty_driver *ptm_driver;
38 static struct tty_driver *pts_driver;
39 #endif
40
41 static void pty_close(struct tty_struct *tty, struct file *filp)
42 {
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;
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,
105                                                                 int count)
106 {
107         struct tty_struct *to = tty->link;
108         int     c;
109
110         if (!to || tty->stopped)
111                 return 0;
112
113         c = to->receive_room;
114         if (c > count)
115                 c = count;
116         to->ldisc.ops->receive_buf(to, buf, NULL, c);
117
118         return c;
119 }
120
121 static int pty_write_room(struct tty_struct *tty)
122 {
123         struct tty_struct *to = tty->link;
124
125         if (!to || tty->stopped)
126                 return 0;
127
128         return to->receive_room;
129 }
130
131 /*
132  *      WSH 05/24/97:  Modified for asymmetric MASTER/SLAVE behavior
133  *      The chars_in_buffer() value is used by the ldisc select() function
134  *      to hold off writing when chars_in_buffer > WAKEUP_CHARS (== 256).
135  *      The pty driver chars_in_buffer() Master/Slave must behave differently:
136  *
137  *      The Master side needs to allow typed-ahead commands to accumulate
138  *      while being canonicalized, so we report "our buffer" as empty until
139  *      some threshold is reached, and then report the count. (Any count >
140  *      WAKEUP_CHARS is regarded by select() as "full".)  To avoid deadlock
141  *      the count returned must be 0 if no canonical data is available to be
142  *      read. (The N_TTY ldisc.chars_in_buffer now knows this.)
143  *
144  *      The Slave side passes all characters in raw mode to the Master side's
145  *      buffer where they can be read immediately, so in this case we can
146  *      return the true count in the buffer.
147  */
148 static int pty_chars_in_buffer(struct tty_struct *tty)
149 {
150         struct tty_struct *to = tty->link;
151         int count;
152
153         /* We should get the line discipline lock for "tty->link" */
154         if (!to || !to->ldisc.ops->chars_in_buffer)
155                 return 0;
156
157         /* The ldisc must report 0 if no characters available to be read */
158         count = to->ldisc.ops->chars_in_buffer(to);
159
160         if (tty->driver->subtype == PTY_TYPE_SLAVE)
161                 return count;
162
163         /* Master side driver ... if the other side's read buffer is less than
164          * half full, return 0 to allow writers to proceed; otherwise return
165          * the count.  This leaves a comfortable margin to avoid overflow,
166          * and still allows half a buffer's worth of typed-ahead commands.
167          */
168         return (count < N_TTY_BUF_SIZE/2) ? 0 : count;
169 }
170
171 /* Set the lock flag on a pty */
172 static int pty_set_lock(struct tty_struct *tty, int __user *arg)
173 {
174         int val;
175         if (get_user(val, arg))
176                 return -EFAULT;
177         if (val)
178                 set_bit(TTY_PTY_LOCK, &tty->flags);
179         else
180                 clear_bit(TTY_PTY_LOCK, &tty->flags);
181         return 0;
182 }
183
184 static void pty_flush_buffer(struct tty_struct *tty)
185 {
186         struct tty_struct *to = tty->link;
187         unsigned long flags;
188
189         if (!to)
190                 return;
191
192         if (to->ldisc.ops->flush_buffer)
193                 to->ldisc.ops->flush_buffer(to);
194
195         if (to->packet) {
196                 spin_lock_irqsave(&tty->ctrl_lock, flags);
197                 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
198                 wake_up_interruptible(&to->read_wait);
199                 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
200         }
201 }
202
203 static int pty_open(struct tty_struct *tty, struct file *filp)
204 {
205         int     retval = -ENODEV;
206
207         if (!tty || !tty->link)
208                 goto out;
209
210         retval = -EIO;
211         if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
212                 goto out;
213         if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
214                 goto out;
215         if (tty->link->count != 1)
216                 goto out;
217
218         clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
219         set_bit(TTY_THROTTLED, &tty->flags);
220         set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
221         retval = 0;
222 out:
223         return retval;
224 }
225
226 static void pty_set_termios(struct tty_struct *tty,
227                                         struct ktermios *old_termios)
228 {
229         tty->termios->c_cflag &= ~(CSIZE | PARENB);
230         tty->termios->c_cflag |= (CS8 | CREAD);
231 }
232
233 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
234 {
235         struct tty_struct *o_tty;
236         int idx = tty->index;
237         int retval;
238
239         o_tty = alloc_tty_struct();
240         if (!o_tty)
241                 return -ENOMEM;
242         if (!try_module_get(driver->other->owner)) {
243                 /* This cannot in fact currently happen */
244                 free_tty_struct(o_tty);
245                 return -ENOMEM;
246         }
247         initialize_tty_struct(o_tty, driver->other, idx);
248
249         /* We always use new tty termios data so we can do this
250            the easy way .. */
251         retval = tty_init_termios(tty);
252         if (retval)
253                 goto free_mem_out;
254
255         retval = tty_init_termios(o_tty);
256         if (retval) {
257                 tty_free_termios(tty);
258                 goto free_mem_out;
259         }
260
261         /*
262          * Everything allocated ... set up the o_tty structure.
263          */
264         driver->other->ttys[idx] = o_tty;
265         tty_driver_kref_get(driver->other);
266         if (driver->subtype == PTY_TYPE_MASTER)
267                 o_tty->count++;
268         /* Establish the links in both directions */
269         tty->link   = o_tty;
270         o_tty->link = tty;
271
272         tty_driver_kref_get(driver);
273         tty->count++;
274         driver->ttys[idx] = tty;
275         return 0;
276 free_mem_out:
277         module_put(o_tty->driver->owner);
278         free_tty_struct(o_tty);
279         return -ENOMEM;
280 }
281
282
283 static const struct tty_operations pty_ops = {
284         .install = pty_install,
285         .open = pty_open,
286         .close = pty_close,
287         .write = pty_write,
288         .write_room = pty_write_room,
289         .flush_buffer = pty_flush_buffer,
290         .chars_in_buffer = pty_chars_in_buffer,
291         .unthrottle = pty_unthrottle,
292         .set_termios = pty_set_termios,
293 };
294
295 /* Traditional BSD devices */
296 #ifdef CONFIG_LEGACY_PTYS
297 static struct tty_driver *pty_driver, *pty_slave_driver;
298
299 static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
300                          unsigned int cmd, unsigned long arg)
301 {
302         switch (cmd) {
303         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
304                 return pty_set_lock(tty, (int __user *) arg);
305         }
306         return -ENOIOCTLCMD;
307 }
308
309 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
310 module_param(legacy_count, int, 0);
311
312 static const struct tty_operations pty_ops_bsd = {
313         .open = pty_open,
314         .close = pty_close,
315         .write = pty_write,
316         .write_room = pty_write_room,
317         .flush_buffer = pty_flush_buffer,
318         .chars_in_buffer = pty_chars_in_buffer,
319         .unthrottle = pty_unthrottle,
320         .set_termios = pty_set_termios,
321         .ioctl = pty_bsd_ioctl,
322 };
323
324 static void __init legacy_pty_init(void)
325 {
326         if (legacy_count <= 0)
327                 return;
328
329         pty_driver = alloc_tty_driver(legacy_count);
330         if (!pty_driver)
331                 panic("Couldn't allocate pty driver");
332
333         pty_slave_driver = alloc_tty_driver(legacy_count);
334         if (!pty_slave_driver)
335                 panic("Couldn't allocate pty slave driver");
336
337         pty_driver->owner = THIS_MODULE;
338         pty_driver->driver_name = "pty_master";
339         pty_driver->name = "pty";
340         pty_driver->major = PTY_MASTER_MAJOR;
341         pty_driver->minor_start = 0;
342         pty_driver->type = TTY_DRIVER_TYPE_PTY;
343         pty_driver->subtype = PTY_TYPE_MASTER;
344         pty_driver->init_termios = tty_std_termios;
345         pty_driver->init_termios.c_iflag = 0;
346         pty_driver->init_termios.c_oflag = 0;
347         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
348         pty_driver->init_termios.c_lflag = 0;
349         pty_driver->init_termios.c_ispeed = 38400;
350         pty_driver->init_termios.c_ospeed = 38400;
351         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
352         pty_driver->other = pty_slave_driver;
353         tty_set_operations(pty_driver, &pty_ops);
354
355         pty_slave_driver->owner = THIS_MODULE;
356         pty_slave_driver->driver_name = "pty_slave";
357         pty_slave_driver->name = "ttyp";
358         pty_slave_driver->major = PTY_SLAVE_MAJOR;
359         pty_slave_driver->minor_start = 0;
360         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
361         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
362         pty_slave_driver->init_termios = tty_std_termios;
363         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
364         pty_slave_driver->init_termios.c_ispeed = 38400;
365         pty_slave_driver->init_termios.c_ospeed = 38400;
366         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
367                                         TTY_DRIVER_REAL_RAW;
368         pty_slave_driver->other = pty_driver;
369         tty_set_operations(pty_slave_driver, &pty_ops);
370
371         if (tty_register_driver(pty_driver))
372                 panic("Couldn't register pty driver");
373         if (tty_register_driver(pty_slave_driver))
374                 panic("Couldn't register pty slave driver");
375 }
376 #else
377 static inline void legacy_pty_init(void) { }
378 #endif
379
380 /* Unix98 devices */
381 #ifdef CONFIG_UNIX98_PTYS
382 /*
383  * sysctl support for setting limits on the number of Unix98 ptys allocated.
384  * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
385  */
386 int pty_limit = NR_UNIX98_PTY_DEFAULT;
387 static int pty_limit_min;
388 static int pty_limit_max = NR_UNIX98_PTY_MAX;
389 static int pty_count;
390
391 static struct cdev ptmx_cdev;
392
393 static struct ctl_table pty_table[] = {
394         {
395                 .ctl_name       = PTY_MAX,
396                 .procname       = "max",
397                 .maxlen         = sizeof(int),
398                 .mode           = 0644,
399                 .data           = &pty_limit,
400                 .proc_handler   = &proc_dointvec_minmax,
401                 .strategy       = &sysctl_intvec,
402                 .extra1         = &pty_limit_min,
403                 .extra2         = &pty_limit_max,
404         }, {
405                 .ctl_name       = PTY_NR,
406                 .procname       = "nr",
407                 .maxlen         = sizeof(int),
408                 .mode           = 0444,
409                 .data           = &pty_count,
410                 .proc_handler   = &proc_dointvec,
411         }, {
412                 .ctl_name       = 0
413         }
414 };
415
416 static struct ctl_table pty_kern_table[] = {
417         {
418                 .ctl_name       = KERN_PTY,
419                 .procname       = "pty",
420                 .mode           = 0555,
421                 .child          = pty_table,
422         },
423         {}
424 };
425
426 static struct ctl_table pty_root_table[] = {
427         {
428                 .ctl_name       = CTL_KERN,
429                 .procname       = "kernel",
430                 .mode           = 0555,
431                 .child          = pty_kern_table,
432         },
433         {}
434 };
435
436
437 static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
438                             unsigned int cmd, unsigned long arg)
439 {
440         switch (cmd) {
441         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
442                 return pty_set_lock(tty, (int __user *)arg);
443         case TIOCGPTN: /* Get PT Number */
444                 return put_user(tty->index, (unsigned int __user *)arg);
445         }
446
447         return -ENOIOCTLCMD;
448 }
449
450 /**
451  *      ptm_unix98_lookup       -       find a pty master
452  *      @driver: ptm driver
453  *      @idx: tty index
454  *
455  *      Look up a pty master device. Called under the tty_mutex for now.
456  *      This provides our locking.
457  */
458
459 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
460                 struct inode *ptm_inode, int idx)
461 {
462         struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
463         if (tty)
464                 tty = tty->link;
465         return tty;
466 }
467
468 /**
469  *      pts_unix98_lookup       -       find a pty slave
470  *      @driver: pts driver
471  *      @idx: tty index
472  *
473  *      Look up a pty master device. Called under the tty_mutex for now.
474  *      This provides our locking.
475  */
476
477 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
478                 struct inode *pts_inode, int idx)
479 {
480         struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
481         /* Master must be open before slave */
482         if (!tty)
483                 return ERR_PTR(-EIO);
484         return tty;
485 }
486
487 static void pty_unix98_shutdown(struct tty_struct *tty)
488 {
489         /* We have our own method as we don't use the tty index */
490         kfree(tty->termios);
491 }
492
493 /* We have no need to install and remove our tty objects as devpts does all
494    the work for us */
495
496 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
497 {
498         struct tty_struct *o_tty;
499         int idx = tty->index;
500
501         o_tty = alloc_tty_struct();
502         if (!o_tty)
503                 return -ENOMEM;
504         if (!try_module_get(driver->other->owner)) {
505                 /* This cannot in fact currently happen */
506                 free_tty_struct(o_tty);
507                 return -ENOMEM;
508         }
509         initialize_tty_struct(o_tty, driver->other, idx);
510
511         tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
512         if (tty->termios == NULL)
513                 goto free_mem_out;
514         *tty->termios = driver->init_termios;
515         tty->termios_locked = tty->termios + 1;
516
517         o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
518         if (o_tty->termios == NULL)
519                 goto free_mem_out;
520         *o_tty->termios = driver->other->init_termios;
521         o_tty->termios_locked = o_tty->termios + 1;
522
523         tty_driver_kref_get(driver->other);
524         if (driver->subtype == PTY_TYPE_MASTER)
525                 o_tty->count++;
526         /* Establish the links in both directions */
527         tty->link   = o_tty;
528         o_tty->link = tty;
529         /*
530          * All structures have been allocated, so now we install them.
531          * Failures after this point use release_tty to clean up, so
532          * there's no need to null out the local pointers.
533          */
534         tty_driver_kref_get(driver);
535         tty->count++;
536         pty_count++;
537         return 0;
538 free_mem_out:
539         kfree(o_tty->termios);
540         module_put(o_tty->driver->owner);
541         free_tty_struct(o_tty);
542         kfree(tty->termios);
543         return -ENOMEM;
544 }
545
546 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
547 {
548         pty_count--;
549 }
550
551 static const struct tty_operations ptm_unix98_ops = {
552         .lookup = ptm_unix98_lookup,
553         .install = pty_unix98_install,
554         .remove = pty_unix98_remove,
555         .open = pty_open,
556         .close = pty_close,
557         .write = pty_write,
558         .write_room = pty_write_room,
559         .flush_buffer = pty_flush_buffer,
560         .chars_in_buffer = pty_chars_in_buffer,
561         .unthrottle = pty_unthrottle,
562         .set_termios = pty_set_termios,
563         .ioctl = pty_unix98_ioctl,
564         .shutdown = pty_unix98_shutdown
565 };
566
567 static const struct tty_operations pty_unix98_ops = {
568         .lookup = pts_unix98_lookup,
569         .install = pty_unix98_install,
570         .remove = pty_unix98_remove,
571         .open = pty_open,
572         .close = pty_close,
573         .write = pty_write,
574         .write_room = pty_write_room,
575         .flush_buffer = pty_flush_buffer,
576         .chars_in_buffer = pty_chars_in_buffer,
577         .unthrottle = pty_unthrottle,
578         .set_termios = pty_set_termios,
579         .shutdown = pty_unix98_shutdown
580 };
581
582 /**
583  *      ptmx_open               -       open a unix 98 pty master
584  *      @inode: inode of device file
585  *      @filp: file pointer to tty
586  *
587  *      Allocate a unix98 pty master device from the ptmx driver.
588  *
589  *      Locking: tty_mutex protects the init_dev work. tty->count should
590  *              protect the rest.
591  *              allocated_ptys_lock handles the list of free pty numbers
592  */
593
594 static int __ptmx_open(struct inode *inode, struct file *filp)
595 {
596         struct tty_struct *tty;
597         int retval;
598         int index;
599
600         nonseekable_open(inode, filp);
601
602         /* find a device that is not in use. */
603         index = devpts_new_index(inode);
604         if (index < 0)
605                 return index;
606
607         mutex_lock(&tty_mutex);
608         tty = tty_init_dev(ptm_driver, index, 1);
609         mutex_unlock(&tty_mutex);
610
611         if (IS_ERR(tty)) {
612                 retval = PTR_ERR(tty);
613                 goto out;
614         }
615
616         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
617         filp->private_data = tty;
618         file_move(filp, &tty->tty_files);
619
620         retval = devpts_pty_new(inode, tty->link);
621         if (retval)
622                 goto out1;
623
624         retval = ptm_driver->ops->open(tty, filp);
625         if (!retval)
626                 return 0;
627 out1:
628         tty_release_dev(filp);
629         return retval;
630 out:
631         devpts_kill_index(inode, index);
632         return retval;
633 }
634
635 static int ptmx_open(struct inode *inode, struct file *filp)
636 {
637         int ret;
638
639         lock_kernel();
640         ret = __ptmx_open(inode, filp);
641         unlock_kernel();
642         return ret;
643 }
644
645 static struct file_operations ptmx_fops;
646
647 static void __init unix98_pty_init(void)
648 {
649         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
650         if (!ptm_driver)
651                 panic("Couldn't allocate Unix98 ptm driver");
652         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
653         if (!pts_driver)
654                 panic("Couldn't allocate Unix98 pts driver");
655
656         ptm_driver->owner = THIS_MODULE;
657         ptm_driver->driver_name = "pty_master";
658         ptm_driver->name = "ptm";
659         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
660         ptm_driver->minor_start = 0;
661         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
662         ptm_driver->subtype = PTY_TYPE_MASTER;
663         ptm_driver->init_termios = tty_std_termios;
664         ptm_driver->init_termios.c_iflag = 0;
665         ptm_driver->init_termios.c_oflag = 0;
666         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
667         ptm_driver->init_termios.c_lflag = 0;
668         ptm_driver->init_termios.c_ispeed = 38400;
669         ptm_driver->init_termios.c_ospeed = 38400;
670         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
671                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
672         ptm_driver->other = pts_driver;
673         tty_set_operations(ptm_driver, &ptm_unix98_ops);
674
675         pts_driver->owner = THIS_MODULE;
676         pts_driver->driver_name = "pty_slave";
677         pts_driver->name = "pts";
678         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
679         pts_driver->minor_start = 0;
680         pts_driver->type = TTY_DRIVER_TYPE_PTY;
681         pts_driver->subtype = PTY_TYPE_SLAVE;
682         pts_driver->init_termios = tty_std_termios;
683         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
684         pts_driver->init_termios.c_ispeed = 38400;
685         pts_driver->init_termios.c_ospeed = 38400;
686         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
687                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
688         pts_driver->other = ptm_driver;
689         tty_set_operations(pts_driver, &pty_unix98_ops);
690
691         if (tty_register_driver(ptm_driver))
692                 panic("Couldn't register Unix98 ptm driver");
693         if (tty_register_driver(pts_driver))
694                 panic("Couldn't register Unix98 pts driver");
695
696         register_sysctl_table(pty_root_table);
697
698         /* Now create the /dev/ptmx special device */
699         tty_default_fops(&ptmx_fops);
700         ptmx_fops.open = ptmx_open;
701
702         cdev_init(&ptmx_cdev, &ptmx_fops);
703         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
704             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
705                 panic("Couldn't register /dev/ptmx driver\n");
706         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
707 }
708
709 #else
710 static inline void unix98_pty_init(void) { }
711 #endif
712
713 static int __init pty_init(void)
714 {
715         legacy_pty_init();
716         unix98_pty_init();
717         return 0;
718 }
719 module_init(pty_init);