da2cb8c70c110d1c4bb2bb87cf446ab4d69f652c
[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/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 #ifdef CONFIG_UNIX98_PTYS
34 static struct tty_driver *ptm_driver;
35 static struct tty_driver *pts_driver;
36 #endif
37
38 static void pty_close(struct tty_struct *tty, struct file *filp)
39 {
40         BUG_ON(!tty);
41         if (tty->driver->subtype == PTY_TYPE_MASTER)
42                 WARN_ON(tty->count > 1);
43         else {
44                 if (tty->count > 2)
45                         return;
46         }
47         wake_up_interruptible(&tty->read_wait);
48         wake_up_interruptible(&tty->write_wait);
49         tty->packet = 0;
50         if (!tty->link)
51                 return;
52         tty->link->packet = 0;
53         set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
54         wake_up_interruptible(&tty->link->read_wait);
55         wake_up_interruptible(&tty->link->write_wait);
56         if (tty->driver->subtype == PTY_TYPE_MASTER) {
57                 set_bit(TTY_OTHER_CLOSED, &tty->flags);
58 #ifdef CONFIG_UNIX98_PTYS
59                 if (tty->driver == ptm_driver)
60                         devpts_pty_kill(tty->link);
61 #endif
62                 tty_vhangup(tty->link);
63         }
64 }
65
66 /*
67  * The unthrottle routine is called by the line discipline to signal
68  * that it can receive more characters.  For PTY's, the TTY_THROTTLED
69  * flag is always set, to force the line discipline to always call the
70  * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
71  * characters in the queue.  This is necessary since each time this
72  * happens, we need to wake up any sleeping processes that could be
73  * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
74  * for the pty buffer to be drained.
75  */
76 static void pty_unthrottle(struct tty_struct *tty)
77 {
78         struct tty_struct *o_tty = tty->link;
79
80         if (!o_tty)
81                 return;
82
83         tty_wakeup(o_tty);
84         set_bit(TTY_THROTTLED, &tty->flags);
85 }
86
87 /*
88  * WSH 05/24/97: modified to
89  *   (1) use space in tty->flip instead of a shared temp buffer
90  *       The flip buffers aren't being used for a pty, so there's lots
91  *       of space available.  The buffer is protected by a per-pty
92  *       semaphore that should almost never come under contention.
93  *   (2) avoid redundant copying for cases where count >> receive_room
94  * N.B. Calls from user space may now return an error code instead of
95  * a count.
96  *
97  * FIXME: Our pty_write method is called with our ldisc lock held but
98  * not our partners. We can't just take the other one blindly without
99  * risking deadlocks.
100  */
101 static int pty_write(struct tty_struct *tty, const unsigned char *buf,
102                                                                 int count)
103 {
104         struct tty_struct *to = tty->link;
105         int     c;
106
107         if (!to || tty->stopped)
108                 return 0;
109
110         c = to->receive_room;
111         if (c > count)
112                 c = count;
113         to->ldisc.ops->receive_buf(to, buf, NULL, c);
114
115         return c;
116 }
117
118 static int pty_write_room(struct tty_struct *tty)
119 {
120         struct tty_struct *to = tty->link;
121
122         if (!to || tty->stopped)
123                 return 0;
124
125         return to->receive_room;
126 }
127
128 /*
129  *      WSH 05/24/97:  Modified for asymmetric MASTER/SLAVE behavior
130  *      The chars_in_buffer() value is used by the ldisc select() function
131  *      to hold off writing when chars_in_buffer > WAKEUP_CHARS (== 256).
132  *      The pty driver chars_in_buffer() Master/Slave must behave differently:
133  *
134  *      The Master side needs to allow typed-ahead commands to accumulate
135  *      while being canonicalized, so we report "our buffer" as empty until
136  *      some threshold is reached, and then report the count. (Any count >
137  *      WAKEUP_CHARS is regarded by select() as "full".)  To avoid deadlock
138  *      the count returned must be 0 if no canonical data is available to be
139  *      read. (The N_TTY ldisc.chars_in_buffer now knows this.)
140  *
141  *      The Slave side passes all characters in raw mode to the Master side's
142  *      buffer where they can be read immediately, so in this case we can
143  *      return the true count in the buffer.
144  */
145 static int pty_chars_in_buffer(struct tty_struct *tty)
146 {
147         struct tty_struct *to = tty->link;
148         int count;
149
150         /* We should get the line discipline lock for "tty->link" */
151         if (!to || !to->ldisc.ops->chars_in_buffer)
152                 return 0;
153
154         /* The ldisc must report 0 if no characters available to be read */
155         count = to->ldisc.ops->chars_in_buffer(to);
156
157         if (tty->driver->subtype == PTY_TYPE_SLAVE)
158                 return count;
159
160         /* Master side driver ... if the other side's read buffer is less than
161          * half full, return 0 to allow writers to proceed; otherwise return
162          * the count.  This leaves a comfortable margin to avoid overflow,
163          * and still allows half a buffer's worth of typed-ahead commands.
164          */
165         return (count < N_TTY_BUF_SIZE/2) ? 0 : count;
166 }
167
168 /* Set the lock flag on a pty */
169 static int pty_set_lock(struct tty_struct *tty, int __user *arg)
170 {
171         int val;
172         if (get_user(val, arg))
173                 return -EFAULT;
174         if (val)
175                 set_bit(TTY_PTY_LOCK, &tty->flags);
176         else
177                 clear_bit(TTY_PTY_LOCK, &tty->flags);
178         return 0;
179 }
180
181 static void pty_flush_buffer(struct tty_struct *tty)
182 {
183         struct tty_struct *to = tty->link;
184         unsigned long flags;
185
186         if (!to)
187                 return;
188
189         if (to->ldisc.ops->flush_buffer)
190                 to->ldisc.ops->flush_buffer(to);
191
192         if (to->packet) {
193                 spin_lock_irqsave(&tty->ctrl_lock, flags);
194                 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
195                 wake_up_interruptible(&to->read_wait);
196                 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
197         }
198 }
199
200 static int pty_open(struct tty_struct *tty, struct file *filp)
201 {
202         int     retval = -ENODEV;
203
204         if (!tty || !tty->link)
205                 goto out;
206
207         retval = -EIO;
208         if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
209                 goto out;
210         if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
211                 goto out;
212         if (tty->link->count != 1)
213                 goto out;
214
215         clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
216         set_bit(TTY_THROTTLED, &tty->flags);
217         retval = 0;
218 out:
219         return retval;
220 }
221
222 static void pty_set_termios(struct tty_struct *tty,
223                                         struct ktermios *old_termios)
224 {
225         tty->termios->c_cflag &= ~(CSIZE | PARENB);
226         tty->termios->c_cflag |= (CS8 | CREAD);
227 }
228
229 /**
230  *      pty_do_resize           -       resize event
231  *      @tty: tty being resized
232  *      @ws: window size being set.
233  *
234  *      Update the termios variables and send the neccessary signals to
235  *      peform a terminal resize correctly
236  */
237
238 int pty_resize(struct tty_struct *tty,  struct winsize *ws)
239 {
240         struct pid *pgrp, *rpgrp;
241         unsigned long flags;
242         struct tty_struct *pty = tty->link;
243
244         /* For a PTY we need to lock the tty side */
245         mutex_lock(&tty->termios_mutex);
246         if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
247                 goto done;
248
249         /* Get the PID values and reference them so we can
250            avoid holding the tty ctrl lock while sending signals.
251            We need to lock these individually however. */
252
253         spin_lock_irqsave(&tty->ctrl_lock, flags);
254         pgrp = get_pid(tty->pgrp);
255         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
256
257         spin_lock_irqsave(&pty->ctrl_lock, flags);
258         rpgrp = get_pid(pty->pgrp);
259         spin_unlock_irqrestore(&pty->ctrl_lock, flags);
260
261         if (pgrp)
262                 kill_pgrp(pgrp, SIGWINCH, 1);
263         if (rpgrp != pgrp && rpgrp)
264                 kill_pgrp(rpgrp, SIGWINCH, 1);
265
266         put_pid(pgrp);
267         put_pid(rpgrp);
268
269         tty->winsize = *ws;
270         pty->winsize = *ws;     /* Never used so will go away soon */
271 done:
272         mutex_unlock(&tty->termios_mutex);
273         return 0;
274 }
275
276 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
277 {
278         struct tty_struct *o_tty;
279         int idx = tty->index;
280         int retval;
281
282         o_tty = alloc_tty_struct();
283         if (!o_tty)
284                 return -ENOMEM;
285         if (!try_module_get(driver->other->owner)) {
286                 /* This cannot in fact currently happen */
287                 free_tty_struct(o_tty);
288                 return -ENOMEM;
289         }
290         initialize_tty_struct(o_tty, driver->other, idx);
291
292         /* We always use new tty termios data so we can do this
293            the easy way .. */
294         retval = tty_init_termios(tty);
295         if (retval)
296                 goto free_mem_out;
297
298         retval = tty_init_termios(o_tty);
299         if (retval) {
300                 tty_free_termios(tty);
301                 goto free_mem_out;
302         }
303
304         /*
305          * Everything allocated ... set up the o_tty structure.
306          */
307         driver->other->ttys[idx] = o_tty;
308         tty_driver_kref_get(driver->other);
309         if (driver->subtype == PTY_TYPE_MASTER)
310                 o_tty->count++;
311         /* Establish the links in both directions */
312         tty->link   = o_tty;
313         o_tty->link = tty;
314
315         tty_driver_kref_get(driver);
316         tty->count++;
317         driver->ttys[idx] = tty;
318         return 0;
319 free_mem_out:
320         module_put(o_tty->driver->owner);
321         free_tty_struct(o_tty);
322         return -ENOMEM;
323 }
324
325
326 static const struct tty_operations pty_ops = {
327         .install = pty_install,
328         .open = pty_open,
329         .close = pty_close,
330         .write = pty_write,
331         .write_room = pty_write_room,
332         .flush_buffer = pty_flush_buffer,
333         .chars_in_buffer = pty_chars_in_buffer,
334         .unthrottle = pty_unthrottle,
335         .set_termios = pty_set_termios,
336         .resize = pty_resize
337 };
338
339 /* Traditional BSD devices */
340 #ifdef CONFIG_LEGACY_PTYS
341 static struct tty_driver *pty_driver, *pty_slave_driver;
342
343 static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
344                          unsigned int cmd, unsigned long arg)
345 {
346         switch (cmd) {
347         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
348                 return pty_set_lock(tty, (int __user *) arg);
349         }
350         return -ENOIOCTLCMD;
351 }
352
353 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
354 module_param(legacy_count, int, 0);
355
356 static const struct tty_operations pty_ops_bsd = {
357         .open = pty_open,
358         .close = pty_close,
359         .write = pty_write,
360         .write_room = pty_write_room,
361         .flush_buffer = pty_flush_buffer,
362         .chars_in_buffer = pty_chars_in_buffer,
363         .unthrottle = pty_unthrottle,
364         .set_termios = pty_set_termios,
365         .ioctl = pty_bsd_ioctl,
366         .resize = pty_resize
367 };
368
369 static void __init legacy_pty_init(void)
370 {
371         if (legacy_count <= 0)
372                 return;
373
374         pty_driver = alloc_tty_driver(legacy_count);
375         if (!pty_driver)
376                 panic("Couldn't allocate pty driver");
377
378         pty_slave_driver = alloc_tty_driver(legacy_count);
379         if (!pty_slave_driver)
380                 panic("Couldn't allocate pty slave driver");
381
382         pty_driver->owner = THIS_MODULE;
383         pty_driver->driver_name = "pty_master";
384         pty_driver->name = "pty";
385         pty_driver->major = PTY_MASTER_MAJOR;
386         pty_driver->minor_start = 0;
387         pty_driver->type = TTY_DRIVER_TYPE_PTY;
388         pty_driver->subtype = PTY_TYPE_MASTER;
389         pty_driver->init_termios = tty_std_termios;
390         pty_driver->init_termios.c_iflag = 0;
391         pty_driver->init_termios.c_oflag = 0;
392         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
393         pty_driver->init_termios.c_lflag = 0;
394         pty_driver->init_termios.c_ispeed = 38400;
395         pty_driver->init_termios.c_ospeed = 38400;
396         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
397         pty_driver->other = pty_slave_driver;
398         tty_set_operations(pty_driver, &pty_ops);
399
400         pty_slave_driver->owner = THIS_MODULE;
401         pty_slave_driver->driver_name = "pty_slave";
402         pty_slave_driver->name = "ttyp";
403         pty_slave_driver->major = PTY_SLAVE_MAJOR;
404         pty_slave_driver->minor_start = 0;
405         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
406         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
407         pty_slave_driver->init_termios = tty_std_termios;
408         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
409         pty_slave_driver->init_termios.c_ispeed = 38400;
410         pty_slave_driver->init_termios.c_ospeed = 38400;
411         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
412                                         TTY_DRIVER_REAL_RAW;
413         pty_slave_driver->other = pty_driver;
414         tty_set_operations(pty_slave_driver, &pty_ops);
415
416         if (tty_register_driver(pty_driver))
417                 panic("Couldn't register pty driver");
418         if (tty_register_driver(pty_slave_driver))
419                 panic("Couldn't register pty slave driver");
420 }
421 #else
422 static inline void legacy_pty_init(void) { }
423 #endif
424
425 /* Unix98 devices */
426 #ifdef CONFIG_UNIX98_PTYS
427 /*
428  * sysctl support for setting limits on the number of Unix98 ptys allocated.
429  * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
430  */
431 int pty_limit = NR_UNIX98_PTY_DEFAULT;
432 static int pty_limit_min;
433 static int pty_limit_max = NR_UNIX98_PTY_MAX;
434 static int pty_count;
435
436 static struct cdev ptmx_cdev;
437
438 static struct ctl_table pty_table[] = {
439         {
440                 .ctl_name       = PTY_MAX,
441                 .procname       = "max",
442                 .maxlen         = sizeof(int),
443                 .mode           = 0644,
444                 .data           = &pty_limit,
445                 .proc_handler   = &proc_dointvec_minmax,
446                 .strategy       = &sysctl_intvec,
447                 .extra1         = &pty_limit_min,
448                 .extra2         = &pty_limit_max,
449         }, {
450                 .ctl_name       = PTY_NR,
451                 .procname       = "nr",
452                 .maxlen         = sizeof(int),
453                 .mode           = 0444,
454                 .data           = &pty_count,
455                 .proc_handler   = &proc_dointvec,
456         }, {
457                 .ctl_name       = 0
458         }
459 };
460
461 static struct ctl_table pty_kern_table[] = {
462         {
463                 .ctl_name       = KERN_PTY,
464                 .procname       = "pty",
465                 .mode           = 0555,
466                 .child          = pty_table,
467         },
468         {}
469 };
470
471 static struct ctl_table pty_root_table[] = {
472         {
473                 .ctl_name       = CTL_KERN,
474                 .procname       = "kernel",
475                 .mode           = 0555,
476                 .child          = pty_kern_table,
477         },
478         {}
479 };
480
481
482 static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
483                             unsigned int cmd, unsigned long arg)
484 {
485         switch (cmd) {
486         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
487                 return pty_set_lock(tty, (int __user *)arg);
488         case TIOCGPTN: /* Get PT Number */
489                 return put_user(tty->index, (unsigned int __user *)arg);
490         }
491
492         return -ENOIOCTLCMD;
493 }
494
495 /**
496  *      ptm_unix98_lookup       -       find a pty master
497  *      @driver: ptm driver
498  *      @idx: tty index
499  *
500  *      Look up a pty master device. Called under the tty_mutex for now.
501  *      This provides our locking.
502  */
503
504 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
505                 struct inode *ptm_inode, int idx)
506 {
507         struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
508         if (tty)
509                 tty = tty->link;
510         return tty;
511 }
512
513 /**
514  *      pts_unix98_lookup       -       find a pty slave
515  *      @driver: pts driver
516  *      @idx: tty index
517  *
518  *      Look up a pty master device. Called under the tty_mutex for now.
519  *      This provides our locking.
520  */
521
522 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
523                 struct inode *pts_inode, int idx)
524 {
525         struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
526         /* Master must be open before slave */
527         if (!tty)
528                 return ERR_PTR(-EIO);
529         return tty;
530 }
531
532 static void pty_unix98_shutdown(struct tty_struct *tty)
533 {
534         /* We have our own method as we don't use the tty index */
535         kfree(tty->termios);
536 }
537
538 /* We have no need to install and remove our tty objects as devpts does all
539    the work for us */
540
541 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
542 {
543         struct tty_struct *o_tty;
544         int idx = tty->index;
545
546         o_tty = alloc_tty_struct();
547         if (!o_tty)
548                 return -ENOMEM;
549         if (!try_module_get(driver->other->owner)) {
550                 /* This cannot in fact currently happen */
551                 free_tty_struct(o_tty);
552                 return -ENOMEM;
553         }
554         initialize_tty_struct(o_tty, driver->other, idx);
555
556         tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
557         if (tty->termios == NULL)
558                 goto free_mem_out;
559         *tty->termios = driver->init_termios;
560         tty->termios_locked = tty->termios + 1;
561
562         o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
563         if (o_tty->termios == NULL)
564                 goto free_mem_out;
565         *o_tty->termios = driver->other->init_termios;
566         o_tty->termios_locked = o_tty->termios + 1;
567
568         tty_driver_kref_get(driver->other);
569         if (driver->subtype == PTY_TYPE_MASTER)
570                 o_tty->count++;
571         /* Establish the links in both directions */
572         tty->link   = o_tty;
573         o_tty->link = tty;
574         /*
575          * All structures have been allocated, so now we install them.
576          * Failures after this point use release_tty to clean up, so
577          * there's no need to null out the local pointers.
578          */
579         tty_driver_kref_get(driver);
580         tty->count++;
581         pty_count++;
582         return 0;
583 free_mem_out:
584         kfree(o_tty->termios);
585         module_put(o_tty->driver->owner);
586         free_tty_struct(o_tty);
587         kfree(tty->termios);
588         return -ENOMEM;
589 }
590
591 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
592 {
593         pty_count--;
594 }
595
596 static const struct tty_operations ptm_unix98_ops = {
597         .lookup = ptm_unix98_lookup,
598         .install = pty_unix98_install,
599         .remove = pty_unix98_remove,
600         .open = pty_open,
601         .close = pty_close,
602         .write = pty_write,
603         .write_room = pty_write_room,
604         .flush_buffer = pty_flush_buffer,
605         .chars_in_buffer = pty_chars_in_buffer,
606         .unthrottle = pty_unthrottle,
607         .set_termios = pty_set_termios,
608         .ioctl = pty_unix98_ioctl,
609         .shutdown = pty_unix98_shutdown,
610         .resize = pty_resize
611 };
612
613 static const struct tty_operations pty_unix98_ops = {
614         .lookup = pts_unix98_lookup,
615         .install = pty_unix98_install,
616         .remove = pty_unix98_remove,
617         .open = pty_open,
618         .close = pty_close,
619         .write = pty_write,
620         .write_room = pty_write_room,
621         .flush_buffer = pty_flush_buffer,
622         .chars_in_buffer = pty_chars_in_buffer,
623         .unthrottle = pty_unthrottle,
624         .set_termios = pty_set_termios,
625         .shutdown = pty_unix98_shutdown
626 };
627
628 /**
629  *      ptmx_open               -       open a unix 98 pty master
630  *      @inode: inode of device file
631  *      @filp: file pointer to tty
632  *
633  *      Allocate a unix98 pty master device from the ptmx driver.
634  *
635  *      Locking: tty_mutex protects the init_dev work. tty->count should
636  *              protect the rest.
637  *              allocated_ptys_lock handles the list of free pty numbers
638  */
639
640 static int __ptmx_open(struct inode *inode, struct file *filp)
641 {
642         struct tty_struct *tty;
643         int retval;
644         int index;
645
646         nonseekable_open(inode, filp);
647
648         /* find a device that is not in use. */
649         index = devpts_new_index(inode);
650         if (index < 0)
651                 return index;
652
653         mutex_lock(&tty_mutex);
654         tty = tty_init_dev(ptm_driver, index, 1);
655         mutex_unlock(&tty_mutex);
656
657         if (IS_ERR(tty)) {
658                 retval = PTR_ERR(tty);
659                 goto out;
660         }
661
662         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
663         filp->private_data = tty;
664         file_move(filp, &tty->tty_files);
665
666         retval = devpts_pty_new(inode, tty->link);
667         if (retval)
668                 goto out1;
669
670         retval = ptm_driver->ops->open(tty, filp);
671         if (!retval)
672                 return 0;
673 out1:
674         tty_release_dev(filp);
675         return retval;
676 out:
677         devpts_kill_index(inode, index);
678         return retval;
679 }
680
681 static int ptmx_open(struct inode *inode, struct file *filp)
682 {
683         int ret;
684
685         lock_kernel();
686         ret = __ptmx_open(inode, filp);
687         unlock_kernel();
688         return ret;
689 }
690
691 static struct file_operations ptmx_fops;
692
693 static void __init unix98_pty_init(void)
694 {
695         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
696         if (!ptm_driver)
697                 panic("Couldn't allocate Unix98 ptm driver");
698         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
699         if (!pts_driver)
700                 panic("Couldn't allocate Unix98 pts driver");
701
702         ptm_driver->owner = THIS_MODULE;
703         ptm_driver->driver_name = "pty_master";
704         ptm_driver->name = "ptm";
705         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
706         ptm_driver->minor_start = 0;
707         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
708         ptm_driver->subtype = PTY_TYPE_MASTER;
709         ptm_driver->init_termios = tty_std_termios;
710         ptm_driver->init_termios.c_iflag = 0;
711         ptm_driver->init_termios.c_oflag = 0;
712         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
713         ptm_driver->init_termios.c_lflag = 0;
714         ptm_driver->init_termios.c_ispeed = 38400;
715         ptm_driver->init_termios.c_ospeed = 38400;
716         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
717                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
718         ptm_driver->other = pts_driver;
719         tty_set_operations(ptm_driver, &ptm_unix98_ops);
720
721         pts_driver->owner = THIS_MODULE;
722         pts_driver->driver_name = "pty_slave";
723         pts_driver->name = "pts";
724         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
725         pts_driver->minor_start = 0;
726         pts_driver->type = TTY_DRIVER_TYPE_PTY;
727         pts_driver->subtype = PTY_TYPE_SLAVE;
728         pts_driver->init_termios = tty_std_termios;
729         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
730         pts_driver->init_termios.c_ispeed = 38400;
731         pts_driver->init_termios.c_ospeed = 38400;
732         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
733                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
734         pts_driver->other = ptm_driver;
735         tty_set_operations(pts_driver, &pty_unix98_ops);
736
737         if (tty_register_driver(ptm_driver))
738                 panic("Couldn't register Unix98 ptm driver");
739         if (tty_register_driver(pts_driver))
740                 panic("Couldn't register Unix98 pts driver");
741
742         register_sysctl_table(pty_root_table);
743
744         /* Now create the /dev/ptmx special device */
745         tty_default_fops(&ptmx_fops);
746         ptmx_fops.open = ptmx_open;
747
748         cdev_init(&ptmx_cdev, &ptmx_fops);
749         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
750             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
751                 panic("Couldn't register /dev/ptmx driver\n");
752         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
753 }
754
755 #else
756 static inline void unix98_pty_init(void) { }
757 #endif
758
759 static int __init pty_init(void)
760 {
761         legacy_pty_init();
762         unix98_pty_init();
763         return 0;
764 }
765 module_init(pty_init);