Merge branch 'topic/asoc' into for-linus
[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 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  *      @real_tty: real tty (not the same as tty if using a pty/tty pair)
234  *      @rows: rows (character)
235  *      @cols: cols (character)
236  *
237  *      Update the termios variables and send the neccessary signals to
238  *      peform a terminal resize correctly
239  */
240
241 int pty_resize(struct tty_struct *tty,  struct winsize *ws)
242 {
243         struct pid *pgrp, *rpgrp;
244         unsigned long flags;
245         struct tty_struct *pty = tty->link;
246
247         /* For a PTY we need to lock the tty side */
248         mutex_lock(&tty->termios_mutex);
249         if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
250                 goto done;
251
252         /* Get the PID values and reference them so we can
253            avoid holding the tty ctrl lock while sending signals.
254            We need to lock these individually however. */
255
256         spin_lock_irqsave(&tty->ctrl_lock, flags);
257         pgrp = get_pid(tty->pgrp);
258         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
259
260         spin_lock_irqsave(&pty->ctrl_lock, flags);
261         rpgrp = get_pid(pty->pgrp);
262         spin_unlock_irqrestore(&pty->ctrl_lock, flags);
263
264         if (pgrp)
265                 kill_pgrp(pgrp, SIGWINCH, 1);
266         if (rpgrp != pgrp && rpgrp)
267                 kill_pgrp(rpgrp, SIGWINCH, 1);
268
269         put_pid(pgrp);
270         put_pid(rpgrp);
271
272         tty->winsize = *ws;
273         pty->winsize = *ws;     /* Never used so will go away soon */
274 done:
275         mutex_unlock(&tty->termios_mutex);
276         return 0;
277 }
278
279 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
280 {
281         struct tty_struct *o_tty;
282         int idx = tty->index;
283         int retval;
284
285         o_tty = alloc_tty_struct();
286         if (!o_tty)
287                 return -ENOMEM;
288         if (!try_module_get(driver->other->owner)) {
289                 /* This cannot in fact currently happen */
290                 free_tty_struct(o_tty);
291                 return -ENOMEM;
292         }
293         initialize_tty_struct(o_tty, driver->other, idx);
294
295         /* We always use new tty termios data so we can do this
296            the easy way .. */
297         retval = tty_init_termios(tty);
298         if (retval)
299                 goto free_mem_out;
300
301         retval = tty_init_termios(o_tty);
302         if (retval) {
303                 tty_free_termios(tty);
304                 goto free_mem_out;
305         }
306
307         /*
308          * Everything allocated ... set up the o_tty structure.
309          */
310         driver->other->ttys[idx] = o_tty;
311         tty_driver_kref_get(driver->other);
312         if (driver->subtype == PTY_TYPE_MASTER)
313                 o_tty->count++;
314         /* Establish the links in both directions */
315         tty->link   = o_tty;
316         o_tty->link = tty;
317
318         tty_driver_kref_get(driver);
319         tty->count++;
320         driver->ttys[idx] = tty;
321         return 0;
322 free_mem_out:
323         module_put(o_tty->driver->owner);
324         free_tty_struct(o_tty);
325         return -ENOMEM;
326 }
327
328
329 static const struct tty_operations pty_ops = {
330         .install = pty_install,
331         .open = pty_open,
332         .close = pty_close,
333         .write = pty_write,
334         .write_room = pty_write_room,
335         .flush_buffer = pty_flush_buffer,
336         .chars_in_buffer = pty_chars_in_buffer,
337         .unthrottle = pty_unthrottle,
338         .set_termios = pty_set_termios,
339         .resize = pty_resize
340 };
341
342 /* Traditional BSD devices */
343 #ifdef CONFIG_LEGACY_PTYS
344 static struct tty_driver *pty_driver, *pty_slave_driver;
345
346 static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
347                          unsigned int cmd, unsigned long arg)
348 {
349         switch (cmd) {
350         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
351                 return pty_set_lock(tty, (int __user *) arg);
352         }
353         return -ENOIOCTLCMD;
354 }
355
356 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
357 module_param(legacy_count, int, 0);
358
359 static const struct tty_operations pty_ops_bsd = {
360         .open = pty_open,
361         .close = pty_close,
362         .write = pty_write,
363         .write_room = pty_write_room,
364         .flush_buffer = pty_flush_buffer,
365         .chars_in_buffer = pty_chars_in_buffer,
366         .unthrottle = pty_unthrottle,
367         .set_termios = pty_set_termios,
368         .ioctl = pty_bsd_ioctl,
369         .resize = pty_resize
370 };
371
372 static void __init legacy_pty_init(void)
373 {
374         if (legacy_count <= 0)
375                 return;
376
377         pty_driver = alloc_tty_driver(legacy_count);
378         if (!pty_driver)
379                 panic("Couldn't allocate pty driver");
380
381         pty_slave_driver = alloc_tty_driver(legacy_count);
382         if (!pty_slave_driver)
383                 panic("Couldn't allocate pty slave driver");
384
385         pty_driver->owner = THIS_MODULE;
386         pty_driver->driver_name = "pty_master";
387         pty_driver->name = "pty";
388         pty_driver->major = PTY_MASTER_MAJOR;
389         pty_driver->minor_start = 0;
390         pty_driver->type = TTY_DRIVER_TYPE_PTY;
391         pty_driver->subtype = PTY_TYPE_MASTER;
392         pty_driver->init_termios = tty_std_termios;
393         pty_driver->init_termios.c_iflag = 0;
394         pty_driver->init_termios.c_oflag = 0;
395         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
396         pty_driver->init_termios.c_lflag = 0;
397         pty_driver->init_termios.c_ispeed = 38400;
398         pty_driver->init_termios.c_ospeed = 38400;
399         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
400         pty_driver->other = pty_slave_driver;
401         tty_set_operations(pty_driver, &pty_ops);
402
403         pty_slave_driver->owner = THIS_MODULE;
404         pty_slave_driver->driver_name = "pty_slave";
405         pty_slave_driver->name = "ttyp";
406         pty_slave_driver->major = PTY_SLAVE_MAJOR;
407         pty_slave_driver->minor_start = 0;
408         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
409         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
410         pty_slave_driver->init_termios = tty_std_termios;
411         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
412         pty_slave_driver->init_termios.c_ispeed = 38400;
413         pty_slave_driver->init_termios.c_ospeed = 38400;
414         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
415                                         TTY_DRIVER_REAL_RAW;
416         pty_slave_driver->other = pty_driver;
417         tty_set_operations(pty_slave_driver, &pty_ops);
418
419         if (tty_register_driver(pty_driver))
420                 panic("Couldn't register pty driver");
421         if (tty_register_driver(pty_slave_driver))
422                 panic("Couldn't register pty slave driver");
423 }
424 #else
425 static inline void legacy_pty_init(void) { }
426 #endif
427
428 /* Unix98 devices */
429 #ifdef CONFIG_UNIX98_PTYS
430 /*
431  * sysctl support for setting limits on the number of Unix98 ptys allocated.
432  * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
433  */
434 int pty_limit = NR_UNIX98_PTY_DEFAULT;
435 static int pty_limit_min;
436 static int pty_limit_max = NR_UNIX98_PTY_MAX;
437 static int pty_count;
438
439 static struct cdev ptmx_cdev;
440
441 static struct ctl_table pty_table[] = {
442         {
443                 .ctl_name       = PTY_MAX,
444                 .procname       = "max",
445                 .maxlen         = sizeof(int),
446                 .mode           = 0644,
447                 .data           = &pty_limit,
448                 .proc_handler   = &proc_dointvec_minmax,
449                 .strategy       = &sysctl_intvec,
450                 .extra1         = &pty_limit_min,
451                 .extra2         = &pty_limit_max,
452         }, {
453                 .ctl_name       = PTY_NR,
454                 .procname       = "nr",
455                 .maxlen         = sizeof(int),
456                 .mode           = 0444,
457                 .data           = &pty_count,
458                 .proc_handler   = &proc_dointvec,
459         }, {
460                 .ctl_name       = 0
461         }
462 };
463
464 static struct ctl_table pty_kern_table[] = {
465         {
466                 .ctl_name       = KERN_PTY,
467                 .procname       = "pty",
468                 .mode           = 0555,
469                 .child          = pty_table,
470         },
471         {}
472 };
473
474 static struct ctl_table pty_root_table[] = {
475         {
476                 .ctl_name       = CTL_KERN,
477                 .procname       = "kernel",
478                 .mode           = 0555,
479                 .child          = pty_kern_table,
480         },
481         {}
482 };
483
484
485 static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
486                             unsigned int cmd, unsigned long arg)
487 {
488         switch (cmd) {
489         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
490                 return pty_set_lock(tty, (int __user *)arg);
491         case TIOCGPTN: /* Get PT Number */
492                 return put_user(tty->index, (unsigned int __user *)arg);
493         }
494
495         return -ENOIOCTLCMD;
496 }
497
498 /**
499  *      ptm_unix98_lookup       -       find a pty master
500  *      @driver: ptm driver
501  *      @idx: tty index
502  *
503  *      Look up a pty master device. Called under the tty_mutex for now.
504  *      This provides our locking.
505  */
506
507 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
508                 struct inode *ptm_inode, int idx)
509 {
510         struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
511         if (tty)
512                 tty = tty->link;
513         return tty;
514 }
515
516 /**
517  *      pts_unix98_lookup       -       find a pty slave
518  *      @driver: pts driver
519  *      @idx: tty index
520  *
521  *      Look up a pty master device. Called under the tty_mutex for now.
522  *      This provides our locking.
523  */
524
525 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
526                 struct inode *pts_inode, int idx)
527 {
528         struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
529         /* Master must be open before slave */
530         if (!tty)
531                 return ERR_PTR(-EIO);
532         return tty;
533 }
534
535 static void pty_unix98_shutdown(struct tty_struct *tty)
536 {
537         /* We have our own method as we don't use the tty index */
538         kfree(tty->termios);
539 }
540
541 /* We have no need to install and remove our tty objects as devpts does all
542    the work for us */
543
544 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
545 {
546         struct tty_struct *o_tty;
547         int idx = tty->index;
548
549         o_tty = alloc_tty_struct();
550         if (!o_tty)
551                 return -ENOMEM;
552         if (!try_module_get(driver->other->owner)) {
553                 /* This cannot in fact currently happen */
554                 free_tty_struct(o_tty);
555                 return -ENOMEM;
556         }
557         initialize_tty_struct(o_tty, driver->other, idx);
558
559         tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
560         if (tty->termios == NULL)
561                 goto free_mem_out;
562         *tty->termios = driver->init_termios;
563         tty->termios_locked = tty->termios + 1;
564
565         o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
566         if (o_tty->termios == NULL)
567                 goto free_mem_out;
568         *o_tty->termios = driver->other->init_termios;
569         o_tty->termios_locked = o_tty->termios + 1;
570
571         tty_driver_kref_get(driver->other);
572         if (driver->subtype == PTY_TYPE_MASTER)
573                 o_tty->count++;
574         /* Establish the links in both directions */
575         tty->link   = o_tty;
576         o_tty->link = tty;
577         /*
578          * All structures have been allocated, so now we install them.
579          * Failures after this point use release_tty to clean up, so
580          * there's no need to null out the local pointers.
581          */
582         tty_driver_kref_get(driver);
583         tty->count++;
584         pty_count++;
585         return 0;
586 free_mem_out:
587         kfree(o_tty->termios);
588         module_put(o_tty->driver->owner);
589         free_tty_struct(o_tty);
590         kfree(tty->termios);
591         return -ENOMEM;
592 }
593
594 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
595 {
596         pty_count--;
597 }
598
599 static const struct tty_operations ptm_unix98_ops = {
600         .lookup = ptm_unix98_lookup,
601         .install = pty_unix98_install,
602         .remove = pty_unix98_remove,
603         .open = pty_open,
604         .close = pty_close,
605         .write = pty_write,
606         .write_room = pty_write_room,
607         .flush_buffer = pty_flush_buffer,
608         .chars_in_buffer = pty_chars_in_buffer,
609         .unthrottle = pty_unthrottle,
610         .set_termios = pty_set_termios,
611         .ioctl = pty_unix98_ioctl,
612         .shutdown = pty_unix98_shutdown,
613         .resize = pty_resize
614 };
615
616 static const struct tty_operations pty_unix98_ops = {
617         .lookup = pts_unix98_lookup,
618         .install = pty_unix98_install,
619         .remove = pty_unix98_remove,
620         .open = pty_open,
621         .close = pty_close,
622         .write = pty_write,
623         .write_room = pty_write_room,
624         .flush_buffer = pty_flush_buffer,
625         .chars_in_buffer = pty_chars_in_buffer,
626         .unthrottle = pty_unthrottle,
627         .set_termios = pty_set_termios,
628         .shutdown = pty_unix98_shutdown
629 };
630
631 /**
632  *      ptmx_open               -       open a unix 98 pty master
633  *      @inode: inode of device file
634  *      @filp: file pointer to tty
635  *
636  *      Allocate a unix98 pty master device from the ptmx driver.
637  *
638  *      Locking: tty_mutex protects the init_dev work. tty->count should
639  *              protect the rest.
640  *              allocated_ptys_lock handles the list of free pty numbers
641  */
642
643 static int __ptmx_open(struct inode *inode, struct file *filp)
644 {
645         struct tty_struct *tty;
646         int retval;
647         int index;
648
649         nonseekable_open(inode, filp);
650
651         /* find a device that is not in use. */
652         index = devpts_new_index(inode);
653         if (index < 0)
654                 return index;
655
656         mutex_lock(&tty_mutex);
657         tty = tty_init_dev(ptm_driver, index, 1);
658         mutex_unlock(&tty_mutex);
659
660         if (IS_ERR(tty)) {
661                 retval = PTR_ERR(tty);
662                 goto out;
663         }
664
665         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
666         filp->private_data = tty;
667         file_move(filp, &tty->tty_files);
668
669         retval = devpts_pty_new(inode, tty->link);
670         if (retval)
671                 goto out1;
672
673         retval = ptm_driver->ops->open(tty, filp);
674         if (!retval)
675                 return 0;
676 out1:
677         tty_release_dev(filp);
678         return retval;
679 out:
680         devpts_kill_index(inode, index);
681         return retval;
682 }
683
684 static int ptmx_open(struct inode *inode, struct file *filp)
685 {
686         int ret;
687
688         lock_kernel();
689         ret = __ptmx_open(inode, filp);
690         unlock_kernel();
691         return ret;
692 }
693
694 static struct file_operations ptmx_fops;
695
696 static void __init unix98_pty_init(void)
697 {
698         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
699         if (!ptm_driver)
700                 panic("Couldn't allocate Unix98 ptm driver");
701         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
702         if (!pts_driver)
703                 panic("Couldn't allocate Unix98 pts driver");
704
705         ptm_driver->owner = THIS_MODULE;
706         ptm_driver->driver_name = "pty_master";
707         ptm_driver->name = "ptm";
708         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
709         ptm_driver->minor_start = 0;
710         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
711         ptm_driver->subtype = PTY_TYPE_MASTER;
712         ptm_driver->init_termios = tty_std_termios;
713         ptm_driver->init_termios.c_iflag = 0;
714         ptm_driver->init_termios.c_oflag = 0;
715         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
716         ptm_driver->init_termios.c_lflag = 0;
717         ptm_driver->init_termios.c_ispeed = 38400;
718         ptm_driver->init_termios.c_ospeed = 38400;
719         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
720                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
721         ptm_driver->other = pts_driver;
722         tty_set_operations(ptm_driver, &ptm_unix98_ops);
723
724         pts_driver->owner = THIS_MODULE;
725         pts_driver->driver_name = "pty_slave";
726         pts_driver->name = "pts";
727         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
728         pts_driver->minor_start = 0;
729         pts_driver->type = TTY_DRIVER_TYPE_PTY;
730         pts_driver->subtype = PTY_TYPE_SLAVE;
731         pts_driver->init_termios = tty_std_termios;
732         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
733         pts_driver->init_termios.c_ispeed = 38400;
734         pts_driver->init_termios.c_ospeed = 38400;
735         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
736                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
737         pts_driver->other = ptm_driver;
738         tty_set_operations(pts_driver, &pty_unix98_ops);
739
740         if (tty_register_driver(ptm_driver))
741                 panic("Couldn't register Unix98 ptm driver");
742         if (tty_register_driver(pts_driver))
743                 panic("Couldn't register Unix98 pts driver");
744
745         register_sysctl_table(pty_root_table);
746
747         /* Now create the /dev/ptmx special device */
748         tty_default_fops(&ptmx_fops);
749         ptmx_fops.open = ptmx_open;
750
751         cdev_init(&ptmx_cdev, &ptmx_fops);
752         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
753             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
754                 panic("Couldn't register /dev/ptmx driver\n");
755         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
756 }
757
758 #else
759 static inline void unix98_pty_init(void) { }
760 #endif
761
762 static int __init pty_init(void)
763 {
764         legacy_pty_init();
765         unix98_pty_init();
766         return 0;
767 }
768 module_init(pty_init);