Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
[linux-2.6.git] / drivers / tty / pty.c
1 /*
2  *  Copyright (C) 1991, 1992  Linus Torvalds
3  *
4  *  Added support for a Unix98-style ptmx device.
5  *    -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
6  *
7  *  When reading this code see also fs/devpts. In particular note that the
8  *  driver_data field is used by the devpts side as a binding to the devpts
9  *  inode.
10  */
11
12 #include <linux/module.h>
13
14 #include <linux/errno.h>
15 #include <linux/interrupt.h>
16 #include <linux/tty.h>
17 #include <linux/tty_flip.h>
18 #include <linux/fcntl.h>
19 #include <linux/sched.h>
20 #include <linux/string.h>
21 #include <linux/major.h>
22 #include <linux/mm.h>
23 #include <linux/init.h>
24 #include <linux/sysctl.h>
25 #include <linux/device.h>
26 #include <linux/uaccess.h>
27 #include <linux/bitops.h>
28 #include <linux/devpts_fs.h>
29 #include <linux/slab.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_unlock();
63                 tty_vhangup(tty->link);
64                 tty_lock();
65         }
66 }
67
68 /*
69  * The unthrottle routine is called by the line discipline to signal
70  * that it can receive more characters.  For PTY's, the TTY_THROTTLED
71  * flag is always set, to force the line discipline to always call the
72  * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
73  * characters in the queue.  This is necessary since each time this
74  * happens, we need to wake up any sleeping processes that could be
75  * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
76  * for the pty buffer to be drained.
77  */
78 static void pty_unthrottle(struct tty_struct *tty)
79 {
80         tty_wakeup(tty->link);
81         set_bit(TTY_THROTTLED, &tty->flags);
82 }
83
84 /**
85  *      pty_space       -       report space left for writing
86  *      @to: tty we are writing into
87  *
88  *      The tty buffers allow 64K but we sneak a peak and clip at 8K this
89  *      allows a lot of overspill room for echo and other fun messes to
90  *      be handled properly
91  */
92
93 static int pty_space(struct tty_struct *to)
94 {
95         int n = 8192 - to->buf.memory_used;
96         if (n < 0)
97                 return 0;
98         return n;
99 }
100
101 /**
102  *      pty_write               -       write to a pty
103  *      @tty: the tty we write from
104  *      @buf: kernel buffer of data
105  *      @count: bytes to write
106  *
107  *      Our "hardware" write method. Data is coming from the ldisc which
108  *      may be in a non sleeping state. We simply throw this at the other
109  *      end of the link as if we were an IRQ handler receiving stuff for
110  *      the other side of the pty/tty pair.
111  */
112
113 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
114 {
115         struct tty_struct *to = tty->link;
116
117         if (tty->stopped)
118                 return 0;
119
120         if (c > 0) {
121                 /* Stuff the data into the input queue of the other end */
122                 c = tty_insert_flip_string(to, buf, c);
123                 /* And shovel */
124                 if (c) {
125                         tty_flip_buffer_push(to);
126                         tty_wakeup(tty);
127                 }
128         }
129         return c;
130 }
131
132 /**
133  *      pty_write_room  -       write space
134  *      @tty: tty we are writing from
135  *
136  *      Report how many bytes the ldisc can send into the queue for
137  *      the other device.
138  */
139
140 static int pty_write_room(struct tty_struct *tty)
141 {
142         if (tty->stopped)
143                 return 0;
144         return pty_space(tty->link);
145 }
146
147 /**
148  *      pty_chars_in_buffer     -       characters currently in our tx queue
149  *      @tty: our tty
150  *
151  *      Report how much we have in the transmit queue. As everything is
152  *      instantly at the other end this is easy to implement.
153  */
154
155 static int pty_chars_in_buffer(struct tty_struct *tty)
156 {
157         return 0;
158 }
159
160 /* Set the lock flag on a pty */
161 static int pty_set_lock(struct tty_struct *tty, int __user *arg)
162 {
163         int val;
164         if (get_user(val, arg))
165                 return -EFAULT;
166         if (val)
167                 set_bit(TTY_PTY_LOCK, &tty->flags);
168         else
169                 clear_bit(TTY_PTY_LOCK, &tty->flags);
170         return 0;
171 }
172
173 /* Send a signal to the slave */
174 static int pty_signal(struct tty_struct *tty, int sig)
175 {
176         unsigned long flags;
177         struct pid *pgrp;
178
179         if (tty->link) {
180                 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
181                 pgrp = get_pid(tty->link->pgrp);
182                 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
183
184                 kill_pgrp(pgrp, sig, 1);
185                 put_pid(pgrp);
186         }
187         return 0;
188 }
189
190 static void pty_flush_buffer(struct tty_struct *tty)
191 {
192         struct tty_struct *to = tty->link;
193         unsigned long flags;
194
195         if (!to)
196                 return;
197         /* tty_buffer_flush(to); FIXME */
198         if (to->packet) {
199                 spin_lock_irqsave(&tty->ctrl_lock, flags);
200                 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
201                 wake_up_interruptible(&to->read_wait);
202                 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
203         }
204 }
205
206 static int pty_open(struct tty_struct *tty, struct file *filp)
207 {
208         int     retval = -ENODEV;
209
210         if (!tty || !tty->link)
211                 goto out;
212
213         retval = -EIO;
214         if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
215                 goto out;
216         if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
217                 goto out;
218         if (tty->link->count != 1)
219                 goto out;
220
221         clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
222         set_bit(TTY_THROTTLED, &tty->flags);
223         retval = 0;
224 out:
225         return retval;
226 }
227
228 static void pty_set_termios(struct tty_struct *tty,
229                                         struct ktermios *old_termios)
230 {
231         tty->termios->c_cflag &= ~(CSIZE | PARENB);
232         tty->termios->c_cflag |= (CS8 | CREAD);
233 }
234
235 /**
236  *      pty_do_resize           -       resize event
237  *      @tty: tty being resized
238  *      @ws: window size being set.
239  *
240  *      Update the termios variables and send the necessary signals to
241  *      peform a terminal resize correctly
242  */
243
244 int pty_resize(struct tty_struct *tty,  struct winsize *ws)
245 {
246         struct pid *pgrp, *rpgrp;
247         unsigned long flags;
248         struct tty_struct *pty = tty->link;
249
250         /* For a PTY we need to lock the tty side */
251         mutex_lock(&tty->termios_mutex);
252         if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
253                 goto done;
254
255         /* Get the PID values and reference them so we can
256            avoid holding the tty ctrl lock while sending signals.
257            We need to lock these individually however. */
258
259         spin_lock_irqsave(&tty->ctrl_lock, flags);
260         pgrp = get_pid(tty->pgrp);
261         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
262
263         spin_lock_irqsave(&pty->ctrl_lock, flags);
264         rpgrp = get_pid(pty->pgrp);
265         spin_unlock_irqrestore(&pty->ctrl_lock, flags);
266
267         if (pgrp)
268                 kill_pgrp(pgrp, SIGWINCH, 1);
269         if (rpgrp != pgrp && rpgrp)
270                 kill_pgrp(rpgrp, SIGWINCH, 1);
271
272         put_pid(pgrp);
273         put_pid(rpgrp);
274
275         tty->winsize = *ws;
276         pty->winsize = *ws;     /* Never used so will go away soon */
277 done:
278         mutex_unlock(&tty->termios_mutex);
279         return 0;
280 }
281
282 /* Traditional BSD devices */
283 #ifdef CONFIG_LEGACY_PTYS
284
285 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
286 {
287         struct tty_struct *o_tty;
288         int idx = tty->index;
289         int retval;
290
291         o_tty = alloc_tty_struct();
292         if (!o_tty)
293                 return -ENOMEM;
294         if (!try_module_get(driver->other->owner)) {
295                 /* This cannot in fact currently happen */
296                 retval = -ENOMEM;
297                 goto err_free_tty;
298         }
299         initialize_tty_struct(o_tty, driver->other, idx);
300
301         /* We always use new tty termios data so we can do this
302            the easy way .. */
303         retval = tty_init_termios(tty);
304         if (retval)
305                 goto err_deinit_tty;
306
307         retval = tty_init_termios(o_tty);
308         if (retval)
309                 goto err_free_termios;
310
311         /*
312          * Everything allocated ... set up the o_tty structure.
313          */
314         driver->other->ttys[idx] = o_tty;
315         tty_driver_kref_get(driver->other);
316         if (driver->subtype == PTY_TYPE_MASTER)
317                 o_tty->count++;
318         /* Establish the links in both directions */
319         tty->link   = o_tty;
320         o_tty->link = tty;
321
322         tty_driver_kref_get(driver);
323         tty->count++;
324         driver->ttys[idx] = tty;
325         return 0;
326 err_free_termios:
327         tty_free_termios(tty);
328 err_deinit_tty:
329         deinitialize_tty_struct(o_tty);
330         module_put(o_tty->driver->owner);
331 err_free_tty:
332         free_tty_struct(o_tty);
333         return retval;
334 }
335
336 static int pty_bsd_ioctl(struct tty_struct *tty,
337                          unsigned int cmd, unsigned long arg)
338 {
339         switch (cmd) {
340         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
341                 return pty_set_lock(tty, (int __user *) arg);
342         case TIOCSIG:    /* Send signal to other side of pty */
343                 return pty_signal(tty, (int) arg);
344         }
345         return -ENOIOCTLCMD;
346 }
347
348 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
349 module_param(legacy_count, int, 0);
350
351 /*
352  * The master side of a pty can do TIOCSPTLCK and thus
353  * has pty_bsd_ioctl.
354  */
355 static const struct tty_operations master_pty_ops_bsd = {
356         .install = pty_install,
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 const struct tty_operations slave_pty_ops_bsd = {
370         .install = pty_install,
371         .open = pty_open,
372         .close = pty_close,
373         .write = pty_write,
374         .write_room = pty_write_room,
375         .flush_buffer = pty_flush_buffer,
376         .chars_in_buffer = pty_chars_in_buffer,
377         .unthrottle = pty_unthrottle,
378         .set_termios = pty_set_termios,
379         .resize = pty_resize
380 };
381
382 static void __init legacy_pty_init(void)
383 {
384         struct tty_driver *pty_driver, *pty_slave_driver;
385
386         if (legacy_count <= 0)
387                 return;
388
389         pty_driver = alloc_tty_driver(legacy_count);
390         if (!pty_driver)
391                 panic("Couldn't allocate pty driver");
392
393         pty_slave_driver = alloc_tty_driver(legacy_count);
394         if (!pty_slave_driver)
395                 panic("Couldn't allocate pty slave driver");
396
397         pty_driver->owner = THIS_MODULE;
398         pty_driver->driver_name = "pty_master";
399         pty_driver->name = "pty";
400         pty_driver->major = PTY_MASTER_MAJOR;
401         pty_driver->minor_start = 0;
402         pty_driver->type = TTY_DRIVER_TYPE_PTY;
403         pty_driver->subtype = PTY_TYPE_MASTER;
404         pty_driver->init_termios = tty_std_termios;
405         pty_driver->init_termios.c_iflag = 0;
406         pty_driver->init_termios.c_oflag = 0;
407         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
408         pty_driver->init_termios.c_lflag = 0;
409         pty_driver->init_termios.c_ispeed = 38400;
410         pty_driver->init_termios.c_ospeed = 38400;
411         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
412         pty_driver->other = pty_slave_driver;
413         tty_set_operations(pty_driver, &master_pty_ops_bsd);
414
415         pty_slave_driver->owner = THIS_MODULE;
416         pty_slave_driver->driver_name = "pty_slave";
417         pty_slave_driver->name = "ttyp";
418         pty_slave_driver->major = PTY_SLAVE_MAJOR;
419         pty_slave_driver->minor_start = 0;
420         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
421         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
422         pty_slave_driver->init_termios = tty_std_termios;
423         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
424         pty_slave_driver->init_termios.c_ispeed = 38400;
425         pty_slave_driver->init_termios.c_ospeed = 38400;
426         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
427                                         TTY_DRIVER_REAL_RAW;
428         pty_slave_driver->other = pty_driver;
429         tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
430
431         if (tty_register_driver(pty_driver))
432                 panic("Couldn't register pty driver");
433         if (tty_register_driver(pty_slave_driver))
434                 panic("Couldn't register pty slave driver");
435 }
436 #else
437 static inline void legacy_pty_init(void) { }
438 #endif
439
440 /* Unix98 devices */
441 #ifdef CONFIG_UNIX98_PTYS
442 /*
443  * sysctl support for setting limits on the number of Unix98 ptys allocated.
444  * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
445  */
446 int pty_limit = NR_UNIX98_PTY_DEFAULT;
447 static int pty_limit_min;
448 static int pty_limit_max = NR_UNIX98_PTY_MAX;
449 static int tty_count;
450 static int pty_count;
451
452 static inline void pty_inc_count(void)
453 {
454         pty_count = (++tty_count) / 2;
455 }
456
457 static inline void pty_dec_count(void)
458 {
459         pty_count = (--tty_count) / 2;
460 }
461
462 static struct cdev ptmx_cdev;
463
464 static struct ctl_table pty_table[] = {
465         {
466                 .procname       = "max",
467                 .maxlen         = sizeof(int),
468                 .mode           = 0644,
469                 .data           = &pty_limit,
470                 .proc_handler   = proc_dointvec_minmax,
471                 .extra1         = &pty_limit_min,
472                 .extra2         = &pty_limit_max,
473         }, {
474                 .procname       = "nr",
475                 .maxlen         = sizeof(int),
476                 .mode           = 0444,
477                 .data           = &pty_count,
478                 .proc_handler   = proc_dointvec,
479         }, 
480         {}
481 };
482
483 static struct ctl_table pty_kern_table[] = {
484         {
485                 .procname       = "pty",
486                 .mode           = 0555,
487                 .child          = pty_table,
488         },
489         {}
490 };
491
492 static struct ctl_table pty_root_table[] = {
493         {
494                 .procname       = "kernel",
495                 .mode           = 0555,
496                 .child          = pty_kern_table,
497         },
498         {}
499 };
500
501
502 static int pty_unix98_ioctl(struct tty_struct *tty,
503                             unsigned int cmd, unsigned long arg)
504 {
505         switch (cmd) {
506         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
507                 return pty_set_lock(tty, (int __user *)arg);
508         case TIOCGPTN: /* Get PT Number */
509                 return put_user(tty->index, (unsigned int __user *)arg);
510         case TIOCSIG:    /* Send signal to other side of pty */
511                 return pty_signal(tty, (int) arg);
512         }
513
514         return -ENOIOCTLCMD;
515 }
516
517 /**
518  *      ptm_unix98_lookup       -       find a pty master
519  *      @driver: ptm driver
520  *      @idx: tty index
521  *
522  *      Look up a pty master device. Called under the tty_mutex for now.
523  *      This provides our locking.
524  */
525
526 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
527                 struct inode *ptm_inode, int idx)
528 {
529         struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
530         if (tty)
531                 tty = tty->link;
532         return tty;
533 }
534
535 /**
536  *      pts_unix98_lookup       -       find a pty slave
537  *      @driver: pts driver
538  *      @idx: tty index
539  *
540  *      Look up a pty master device. Called under the tty_mutex for now.
541  *      This provides our locking.
542  */
543
544 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
545                 struct inode *pts_inode, int idx)
546 {
547         struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
548         /* Master must be open before slave */
549         if (!tty)
550                 return ERR_PTR(-EIO);
551         return tty;
552 }
553
554 static void pty_unix98_shutdown(struct tty_struct *tty)
555 {
556         tty_driver_remove_tty(tty->driver, tty);
557         /* We have our own method as we don't use the tty index */
558         kfree(tty->termios);
559 }
560
561 /* We have no need to install and remove our tty objects as devpts does all
562    the work for us */
563
564 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
565 {
566         struct tty_struct *o_tty;
567         int idx = tty->index;
568
569         o_tty = alloc_tty_struct();
570         if (!o_tty)
571                 return -ENOMEM;
572         if (!try_module_get(driver->other->owner)) {
573                 /* This cannot in fact currently happen */
574                 goto err_free_tty;
575         }
576         initialize_tty_struct(o_tty, driver->other, idx);
577
578         tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
579         if (tty->termios == NULL)
580                 goto err_free_mem;
581         *tty->termios = driver->init_termios;
582         tty->termios_locked = tty->termios + 1;
583
584         o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
585         if (o_tty->termios == NULL)
586                 goto err_free_mem;
587         *o_tty->termios = driver->other->init_termios;
588         o_tty->termios_locked = o_tty->termios + 1;
589
590         tty_driver_kref_get(driver->other);
591         if (driver->subtype == PTY_TYPE_MASTER)
592                 o_tty->count++;
593         /* Establish the links in both directions */
594         tty->link   = o_tty;
595         o_tty->link = tty;
596         /*
597          * All structures have been allocated, so now we install them.
598          * Failures after this point use release_tty to clean up, so
599          * there's no need to null out the local pointers.
600          */
601         tty_driver_kref_get(driver);
602         tty->count++;
603         pty_inc_count(); /* tty */
604         pty_inc_count(); /* tty->link */
605         return 0;
606 err_free_mem:
607         deinitialize_tty_struct(o_tty);
608         kfree(o_tty->termios);
609         kfree(tty->termios);
610         module_put(o_tty->driver->owner);
611 err_free_tty:
612         free_tty_struct(o_tty);
613         return -ENOMEM;
614 }
615
616 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
617 {
618         pty_dec_count();
619 }
620
621 static const struct tty_operations ptm_unix98_ops = {
622         .lookup = ptm_unix98_lookup,
623         .install = pty_unix98_install,
624         .remove = pty_unix98_remove,
625         .open = pty_open,
626         .close = pty_close,
627         .write = pty_write,
628         .write_room = pty_write_room,
629         .flush_buffer = pty_flush_buffer,
630         .chars_in_buffer = pty_chars_in_buffer,
631         .unthrottle = pty_unthrottle,
632         .set_termios = pty_set_termios,
633         .ioctl = pty_unix98_ioctl,
634         .shutdown = pty_unix98_shutdown,
635         .resize = pty_resize
636 };
637
638 static const struct tty_operations pty_unix98_ops = {
639         .lookup = pts_unix98_lookup,
640         .install = pty_unix98_install,
641         .remove = pty_unix98_remove,
642         .open = pty_open,
643         .close = pty_close,
644         .write = pty_write,
645         .write_room = pty_write_room,
646         .flush_buffer = pty_flush_buffer,
647         .chars_in_buffer = pty_chars_in_buffer,
648         .unthrottle = pty_unthrottle,
649         .set_termios = pty_set_termios,
650         .shutdown = pty_unix98_shutdown
651 };
652
653 /**
654  *      ptmx_open               -       open a unix 98 pty master
655  *      @inode: inode of device file
656  *      @filp: file pointer to tty
657  *
658  *      Allocate a unix98 pty master device from the ptmx driver.
659  *
660  *      Locking: tty_mutex protects the init_dev work. tty->count should
661  *              protect the rest.
662  *              allocated_ptys_lock handles the list of free pty numbers
663  */
664
665 static int ptmx_open(struct inode *inode, struct file *filp)
666 {
667         struct tty_struct *tty;
668         int retval;
669         int index;
670
671         nonseekable_open(inode, filp);
672
673         retval = tty_alloc_file(filp);
674         if (retval)
675                 return retval;
676
677         /* find a device that is not in use. */
678         tty_lock();
679         index = devpts_new_index(inode);
680         tty_unlock();
681         if (index < 0) {
682                 retval = index;
683                 goto err_file;
684         }
685
686         mutex_lock(&tty_mutex);
687         tty_lock();
688         tty = tty_init_dev(ptm_driver, index, 1);
689         mutex_unlock(&tty_mutex);
690
691         if (IS_ERR(tty)) {
692                 retval = PTR_ERR(tty);
693                 goto out;
694         }
695
696         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
697
698         tty_add_file(tty, filp);
699
700         retval = devpts_pty_new(inode, tty->link);
701         if (retval)
702                 goto err_release;
703
704         retval = ptm_driver->ops->open(tty, filp);
705         if (retval)
706                 goto err_release;
707
708         tty_unlock();
709         return 0;
710 err_release:
711         tty_unlock();
712         tty_release(inode, filp);
713         return retval;
714 out:
715         devpts_kill_index(inode, index);
716         tty_unlock();
717 err_file:
718         tty_free_file(filp);
719         return retval;
720 }
721
722 static struct file_operations ptmx_fops;
723
724 static void __init unix98_pty_init(void)
725 {
726         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
727         if (!ptm_driver)
728                 panic("Couldn't allocate Unix98 ptm driver");
729         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
730         if (!pts_driver)
731                 panic("Couldn't allocate Unix98 pts driver");
732
733         ptm_driver->owner = THIS_MODULE;
734         ptm_driver->driver_name = "pty_master";
735         ptm_driver->name = "ptm";
736         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
737         ptm_driver->minor_start = 0;
738         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
739         ptm_driver->subtype = PTY_TYPE_MASTER;
740         ptm_driver->init_termios = tty_std_termios;
741         ptm_driver->init_termios.c_iflag = 0;
742         ptm_driver->init_termios.c_oflag = 0;
743         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
744         ptm_driver->init_termios.c_lflag = 0;
745         ptm_driver->init_termios.c_ispeed = 38400;
746         ptm_driver->init_termios.c_ospeed = 38400;
747         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
748                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
749         ptm_driver->other = pts_driver;
750         tty_set_operations(ptm_driver, &ptm_unix98_ops);
751
752         pts_driver->owner = THIS_MODULE;
753         pts_driver->driver_name = "pty_slave";
754         pts_driver->name = "pts";
755         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
756         pts_driver->minor_start = 0;
757         pts_driver->type = TTY_DRIVER_TYPE_PTY;
758         pts_driver->subtype = PTY_TYPE_SLAVE;
759         pts_driver->init_termios = tty_std_termios;
760         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
761         pts_driver->init_termios.c_ispeed = 38400;
762         pts_driver->init_termios.c_ospeed = 38400;
763         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
764                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
765         pts_driver->other = ptm_driver;
766         tty_set_operations(pts_driver, &pty_unix98_ops);
767
768         if (tty_register_driver(ptm_driver))
769                 panic("Couldn't register Unix98 ptm driver");
770         if (tty_register_driver(pts_driver))
771                 panic("Couldn't register Unix98 pts driver");
772
773         register_sysctl_table(pty_root_table);
774
775         /* Now create the /dev/ptmx special device */
776         tty_default_fops(&ptmx_fops);
777         ptmx_fops.open = ptmx_open;
778
779         cdev_init(&ptmx_cdev, &ptmx_fops);
780         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
781             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
782                 panic("Couldn't register /dev/ptmx driver\n");
783         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
784 }
785
786 #else
787 static inline void unix98_pty_init(void) { }
788 #endif
789
790 static int __init pty_init(void)
791 {
792         legacy_pty_init();
793         unix98_pty_init();
794         return 0;
795 }
796 module_init(pty_init);