tty: fix up atime/mtime mess, take three
[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/device.h>
25 #include <linux/uaccess.h>
26 #include <linux/bitops.h>
27 #include <linux/devpts_fs.h>
28 #include <linux/slab.h>
29
30
31 #ifdef CONFIG_UNIX98_PTYS
32 static struct tty_driver *ptm_driver;
33 static struct tty_driver *pts_driver;
34 #endif
35
36 static void pty_close(struct tty_struct *tty, struct file *filp)
37 {
38         BUG_ON(!tty);
39         if (tty->driver->subtype == PTY_TYPE_MASTER)
40                 WARN_ON(tty->count > 1);
41         else {
42                 if (tty->count > 2)
43                         return;
44         }
45         wake_up_interruptible(&tty->read_wait);
46         wake_up_interruptible(&tty->write_wait);
47         tty->packet = 0;
48         if (!tty->link)
49                 return;
50         set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
51         wake_up_interruptible(&tty->link->read_wait);
52         wake_up_interruptible(&tty->link->write_wait);
53         if (tty->driver->subtype == PTY_TYPE_MASTER) {
54                 set_bit(TTY_OTHER_CLOSED, &tty->flags);
55 #ifdef CONFIG_UNIX98_PTYS
56                 if (tty->driver == ptm_driver)
57                         devpts_pty_kill(tty->link);
58 #endif
59                 tty_unlock();
60                 tty_vhangup(tty->link);
61                 tty_lock();
62         }
63 }
64
65 /*
66  * The unthrottle routine is called by the line discipline to signal
67  * that it can receive more characters.  For PTY's, the TTY_THROTTLED
68  * flag is always set, to force the line discipline to always call the
69  * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
70  * characters in the queue.  This is necessary since each time this
71  * happens, we need to wake up any sleeping processes that could be
72  * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
73  * for the pty buffer to be drained.
74  */
75 static void pty_unthrottle(struct tty_struct *tty)
76 {
77         tty_wakeup(tty->link);
78         set_bit(TTY_THROTTLED, &tty->flags);
79 }
80
81 /**
82  *      pty_space       -       report space left for writing
83  *      @to: tty we are writing into
84  *
85  *      The tty buffers allow 64K but we sneak a peak and clip at 8K this
86  *      allows a lot of overspill room for echo and other fun messes to
87  *      be handled properly
88  */
89
90 static int pty_space(struct tty_struct *to)
91 {
92         int n = 8192 - to->buf.memory_used;
93         if (n < 0)
94                 return 0;
95         return n;
96 }
97
98 /**
99  *      pty_write               -       write to a pty
100  *      @tty: the tty we write from
101  *      @buf: kernel buffer of data
102  *      @count: bytes to write
103  *
104  *      Our "hardware" write method. Data is coming from the ldisc which
105  *      may be in a non sleeping state. We simply throw this at the other
106  *      end of the link as if we were an IRQ handler receiving stuff for
107  *      the other side of the pty/tty pair.
108  */
109
110 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
111 {
112         struct tty_struct *to = tty->link;
113
114         if (tty->stopped)
115                 return 0;
116
117         if (c > 0) {
118                 /* Stuff the data into the input queue of the other end */
119                 c = tty_insert_flip_string(to, buf, c);
120                 /* And shovel */
121                 if (c) {
122                         tty_flip_buffer_push(to);
123                         tty_wakeup(tty);
124                 }
125         }
126         return c;
127 }
128
129 /**
130  *      pty_write_room  -       write space
131  *      @tty: tty we are writing from
132  *
133  *      Report how many bytes the ldisc can send into the queue for
134  *      the other device.
135  */
136
137 static int pty_write_room(struct tty_struct *tty)
138 {
139         if (tty->stopped)
140                 return 0;
141         return pty_space(tty->link);
142 }
143
144 /**
145  *      pty_chars_in_buffer     -       characters currently in our tx queue
146  *      @tty: our tty
147  *
148  *      Report how much we have in the transmit queue. As everything is
149  *      instantly at the other end this is easy to implement.
150  */
151
152 static int pty_chars_in_buffer(struct tty_struct *tty)
153 {
154         return 0;
155 }
156
157 /* Set the lock flag on a pty */
158 static int pty_set_lock(struct tty_struct *tty, int __user *arg)
159 {
160         int val;
161         if (get_user(val, arg))
162                 return -EFAULT;
163         if (val)
164                 set_bit(TTY_PTY_LOCK, &tty->flags);
165         else
166                 clear_bit(TTY_PTY_LOCK, &tty->flags);
167         return 0;
168 }
169
170 /* Send a signal to the slave */
171 static int pty_signal(struct tty_struct *tty, int sig)
172 {
173         unsigned long flags;
174         struct pid *pgrp;
175
176         if (tty->link) {
177                 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
178                 pgrp = get_pid(tty->link->pgrp);
179                 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
180
181                 kill_pgrp(pgrp, sig, 1);
182                 put_pid(pgrp);
183         }
184         return 0;
185 }
186
187 static void pty_flush_buffer(struct tty_struct *tty)
188 {
189         struct tty_struct *to = tty->link;
190         unsigned long flags;
191
192         if (!to)
193                 return;
194         /* tty_buffer_flush(to); FIXME */
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         retval = 0;
221 out:
222         return retval;
223 }
224
225 static void pty_set_termios(struct tty_struct *tty,
226                                         struct ktermios *old_termios)
227 {
228         tty->termios->c_cflag &= ~(CSIZE | PARENB);
229         tty->termios->c_cflag |= (CS8 | CREAD);
230 }
231
232 /**
233  *      pty_do_resize           -       resize event
234  *      @tty: tty being resized
235  *      @ws: window size being set.
236  *
237  *      Update the termios variables and send the necessary 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 /* Traditional BSD devices */
280 #ifdef CONFIG_LEGACY_PTYS
281
282 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
283 {
284         struct tty_struct *o_tty;
285         int idx = tty->index;
286         int retval;
287
288         o_tty = alloc_tty_struct();
289         if (!o_tty)
290                 return -ENOMEM;
291         if (!try_module_get(driver->other->owner)) {
292                 /* This cannot in fact currently happen */
293                 retval = -ENOMEM;
294                 goto err_free_tty;
295         }
296         initialize_tty_struct(o_tty, driver->other, idx);
297
298         /* We always use new tty termios data so we can do this
299            the easy way .. */
300         retval = tty_init_termios(tty);
301         if (retval)
302                 goto err_deinit_tty;
303
304         retval = tty_init_termios(o_tty);
305         if (retval)
306                 goto err_free_termios;
307
308         /*
309          * Everything allocated ... set up the o_tty structure.
310          */
311         driver->other->ttys[idx] = o_tty;
312         tty_driver_kref_get(driver->other);
313         if (driver->subtype == PTY_TYPE_MASTER)
314                 o_tty->count++;
315         /* Establish the links in both directions */
316         tty->link   = o_tty;
317         o_tty->link = tty;
318
319         tty_driver_kref_get(driver);
320         tty->count++;
321         driver->ttys[idx] = tty;
322         return 0;
323 err_free_termios:
324         tty_free_termios(tty);
325 err_deinit_tty:
326         deinitialize_tty_struct(o_tty);
327         module_put(o_tty->driver->owner);
328 err_free_tty:
329         free_tty_struct(o_tty);
330         return retval;
331 }
332
333 static int pty_bsd_ioctl(struct tty_struct *tty,
334                          unsigned int cmd, unsigned long arg)
335 {
336         switch (cmd) {
337         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
338                 return pty_set_lock(tty, (int __user *) arg);
339         case TIOCSIG:    /* Send signal to other side of pty */
340                 return pty_signal(tty, (int) arg);
341         }
342         return -ENOIOCTLCMD;
343 }
344
345 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
346 module_param(legacy_count, int, 0);
347
348 /*
349  * The master side of a pty can do TIOCSPTLCK and thus
350  * has pty_bsd_ioctl.
351  */
352 static const struct tty_operations master_pty_ops_bsd = {
353         .install = pty_install,
354         .open = pty_open,
355         .close = pty_close,
356         .write = pty_write,
357         .write_room = pty_write_room,
358         .flush_buffer = pty_flush_buffer,
359         .chars_in_buffer = pty_chars_in_buffer,
360         .unthrottle = pty_unthrottle,
361         .set_termios = pty_set_termios,
362         .ioctl = pty_bsd_ioctl,
363         .resize = pty_resize
364 };
365
366 static const struct tty_operations slave_pty_ops_bsd = {
367         .install = pty_install,
368         .open = pty_open,
369         .close = pty_close,
370         .write = pty_write,
371         .write_room = pty_write_room,
372         .flush_buffer = pty_flush_buffer,
373         .chars_in_buffer = pty_chars_in_buffer,
374         .unthrottle = pty_unthrottle,
375         .set_termios = pty_set_termios,
376         .resize = pty_resize
377 };
378
379 static void __init legacy_pty_init(void)
380 {
381         struct tty_driver *pty_driver, *pty_slave_driver;
382
383         if (legacy_count <= 0)
384                 return;
385
386         pty_driver = alloc_tty_driver(legacy_count);
387         if (!pty_driver)
388                 panic("Couldn't allocate pty driver");
389
390         pty_slave_driver = alloc_tty_driver(legacy_count);
391         if (!pty_slave_driver)
392                 panic("Couldn't allocate pty slave driver");
393
394         pty_driver->driver_name = "pty_master";
395         pty_driver->name = "pty";
396         pty_driver->major = PTY_MASTER_MAJOR;
397         pty_driver->minor_start = 0;
398         pty_driver->type = TTY_DRIVER_TYPE_PTY;
399         pty_driver->subtype = PTY_TYPE_MASTER;
400         pty_driver->init_termios = tty_std_termios;
401         pty_driver->init_termios.c_iflag = 0;
402         pty_driver->init_termios.c_oflag = 0;
403         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
404         pty_driver->init_termios.c_lflag = 0;
405         pty_driver->init_termios.c_ispeed = 38400;
406         pty_driver->init_termios.c_ospeed = 38400;
407         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
408         pty_driver->other = pty_slave_driver;
409         tty_set_operations(pty_driver, &master_pty_ops_bsd);
410
411         pty_slave_driver->driver_name = "pty_slave";
412         pty_slave_driver->name = "ttyp";
413         pty_slave_driver->major = PTY_SLAVE_MAJOR;
414         pty_slave_driver->minor_start = 0;
415         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
416         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
417         pty_slave_driver->init_termios = tty_std_termios;
418         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
419         pty_slave_driver->init_termios.c_ispeed = 38400;
420         pty_slave_driver->init_termios.c_ospeed = 38400;
421         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
422                                         TTY_DRIVER_REAL_RAW;
423         pty_slave_driver->other = pty_driver;
424         tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
425
426         if (tty_register_driver(pty_driver))
427                 panic("Couldn't register pty driver");
428         if (tty_register_driver(pty_slave_driver))
429                 panic("Couldn't register pty slave driver");
430 }
431 #else
432 static inline void legacy_pty_init(void) { }
433 #endif
434
435 /* Unix98 devices */
436 #ifdef CONFIG_UNIX98_PTYS
437
438 static struct cdev ptmx_cdev;
439
440 static int pty_unix98_ioctl(struct tty_struct *tty,
441                             unsigned int cmd, unsigned long arg)
442 {
443         switch (cmd) {
444         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
445                 return pty_set_lock(tty, (int __user *)arg);
446         case TIOCGPTN: /* Get PT Number */
447                 return put_user(tty->index, (unsigned int __user *)arg);
448         case TIOCSIG:    /* Send signal to other side of pty */
449                 return pty_signal(tty, (int) arg);
450         }
451
452         return -ENOIOCTLCMD;
453 }
454
455 /**
456  *      ptm_unix98_lookup       -       find a pty master
457  *      @driver: ptm driver
458  *      @idx: tty index
459  *
460  *      Look up a pty master device. Called under the tty_mutex for now.
461  *      This provides our locking.
462  */
463
464 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
465                 struct inode *ptm_inode, int idx)
466 {
467         /* Master must be open via /dev/ptmx */
468         return ERR_PTR(-EIO);
469 }
470
471 /**
472  *      pts_unix98_lookup       -       find a pty slave
473  *      @driver: pts driver
474  *      @idx: tty index
475  *
476  *      Look up a pty master device. Called under the tty_mutex for now.
477  *      This provides our locking.
478  */
479
480 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
481                 struct inode *pts_inode, int idx)
482 {
483         struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
484         /* Master must be open before slave */
485         if (!tty)
486                 return ERR_PTR(-EIO);
487         return tty;
488 }
489
490 static void pty_unix98_shutdown(struct tty_struct *tty)
491 {
492         tty_driver_remove_tty(tty->driver, tty);
493         /* We have our own method as we don't use the tty index */
494         kfree(tty->termios);
495 }
496
497 /* We have no need to install and remove our tty objects as devpts does all
498    the work for us */
499
500 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
501 {
502         struct tty_struct *o_tty;
503         int idx = tty->index;
504
505         o_tty = alloc_tty_struct();
506         if (!o_tty)
507                 return -ENOMEM;
508         if (!try_module_get(driver->other->owner)) {
509                 /* This cannot in fact currently happen */
510                 goto err_free_tty;
511         }
512         initialize_tty_struct(o_tty, driver->other, idx);
513
514         tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
515         if (tty->termios == NULL)
516                 goto err_free_mem;
517         *tty->termios = driver->init_termios;
518         tty->termios_locked = tty->termios + 1;
519
520         o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
521         if (o_tty->termios == NULL)
522                 goto err_free_mem;
523         *o_tty->termios = driver->other->init_termios;
524         o_tty->termios_locked = o_tty->termios + 1;
525
526         tty_driver_kref_get(driver->other);
527         if (driver->subtype == PTY_TYPE_MASTER)
528                 o_tty->count++;
529         /* Establish the links in both directions */
530         tty->link   = o_tty;
531         o_tty->link = tty;
532         /*
533          * All structures have been allocated, so now we install them.
534          * Failures after this point use release_tty to clean up, so
535          * there's no need to null out the local pointers.
536          */
537         tty_driver_kref_get(driver);
538         tty->count++;
539         return 0;
540 err_free_mem:
541         deinitialize_tty_struct(o_tty);
542         kfree(o_tty->termios);
543         kfree(tty->termios);
544         module_put(o_tty->driver->owner);
545 err_free_tty:
546         free_tty_struct(o_tty);
547         return -ENOMEM;
548 }
549
550 static void ptm_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
551 {
552 }
553
554 static void pts_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
555 {
556 }
557
558 static const struct tty_operations ptm_unix98_ops = {
559         .lookup = ptm_unix98_lookup,
560         .install = pty_unix98_install,
561         .remove = ptm_unix98_remove,
562         .open = pty_open,
563         .close = pty_close,
564         .write = pty_write,
565         .write_room = pty_write_room,
566         .flush_buffer = pty_flush_buffer,
567         .chars_in_buffer = pty_chars_in_buffer,
568         .unthrottle = pty_unthrottle,
569         .set_termios = pty_set_termios,
570         .ioctl = pty_unix98_ioctl,
571         .shutdown = pty_unix98_shutdown,
572         .resize = pty_resize
573 };
574
575 static const struct tty_operations pty_unix98_ops = {
576         .lookup = pts_unix98_lookup,
577         .install = pty_unix98_install,
578         .remove = pts_unix98_remove,
579         .open = pty_open,
580         .close = pty_close,
581         .write = pty_write,
582         .write_room = pty_write_room,
583         .flush_buffer = pty_flush_buffer,
584         .chars_in_buffer = pty_chars_in_buffer,
585         .unthrottle = pty_unthrottle,
586         .set_termios = pty_set_termios,
587         .shutdown = pty_unix98_shutdown
588 };
589
590 /**
591  *      ptmx_open               -       open a unix 98 pty master
592  *      @inode: inode of device file
593  *      @filp: file pointer to tty
594  *
595  *      Allocate a unix98 pty master device from the ptmx driver.
596  *
597  *      Locking: tty_mutex protects the init_dev work. tty->count should
598  *              protect the rest.
599  *              allocated_ptys_lock handles the list of free pty numbers
600  */
601
602 static int ptmx_open(struct inode *inode, struct file *filp)
603 {
604         struct tty_struct *tty;
605         int retval;
606         int index;
607
608         nonseekable_open(inode, filp);
609
610         /* We refuse fsnotify events on ptmx, since it's a shared resource */
611         filp->f_mode |= FMODE_NONOTIFY;
612
613         retval = tty_alloc_file(filp);
614         if (retval)
615                 return retval;
616
617         /* find a device that is not in use. */
618         tty_lock();
619         index = devpts_new_index(inode);
620         tty_unlock();
621         if (index < 0) {
622                 retval = index;
623                 goto err_file;
624         }
625
626         mutex_lock(&tty_mutex);
627         tty_lock();
628         tty = tty_init_dev(ptm_driver, index);
629         mutex_unlock(&tty_mutex);
630
631         if (IS_ERR(tty)) {
632                 retval = PTR_ERR(tty);
633                 goto out;
634         }
635
636         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
637
638         tty_add_file(tty, filp);
639
640         retval = devpts_pty_new(inode, tty->link);
641         if (retval)
642                 goto err_release;
643
644         retval = ptm_driver->ops->open(tty, filp);
645         if (retval)
646                 goto err_release;
647
648         tty_unlock();
649         return 0;
650 err_release:
651         tty_unlock();
652         tty_release(inode, filp);
653         return retval;
654 out:
655         devpts_kill_index(inode, index);
656         tty_unlock();
657 err_file:
658         tty_free_file(filp);
659         return retval;
660 }
661
662 static struct file_operations ptmx_fops;
663
664 static void __init unix98_pty_init(void)
665 {
666         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
667         if (!ptm_driver)
668                 panic("Couldn't allocate Unix98 ptm driver");
669         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
670         if (!pts_driver)
671                 panic("Couldn't allocate Unix98 pts driver");
672
673         ptm_driver->driver_name = "pty_master";
674         ptm_driver->name = "ptm";
675         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
676         ptm_driver->minor_start = 0;
677         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
678         ptm_driver->subtype = PTY_TYPE_MASTER;
679         ptm_driver->init_termios = tty_std_termios;
680         ptm_driver->init_termios.c_iflag = 0;
681         ptm_driver->init_termios.c_oflag = 0;
682         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
683         ptm_driver->init_termios.c_lflag = 0;
684         ptm_driver->init_termios.c_ispeed = 38400;
685         ptm_driver->init_termios.c_ospeed = 38400;
686         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
687                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
688         ptm_driver->other = pts_driver;
689         tty_set_operations(ptm_driver, &ptm_unix98_ops);
690
691         pts_driver->driver_name = "pty_slave";
692         pts_driver->name = "pts";
693         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
694         pts_driver->minor_start = 0;
695         pts_driver->type = TTY_DRIVER_TYPE_PTY;
696         pts_driver->subtype = PTY_TYPE_SLAVE;
697         pts_driver->init_termios = tty_std_termios;
698         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
699         pts_driver->init_termios.c_ispeed = 38400;
700         pts_driver->init_termios.c_ospeed = 38400;
701         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
702                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
703         pts_driver->other = ptm_driver;
704         tty_set_operations(pts_driver, &pty_unix98_ops);
705
706         if (tty_register_driver(ptm_driver))
707                 panic("Couldn't register Unix98 ptm driver");
708         if (tty_register_driver(pts_driver))
709                 panic("Couldn't register Unix98 pts driver");
710
711         /* Now create the /dev/ptmx special device */
712         tty_default_fops(&ptmx_fops);
713         ptmx_fops.open = ptmx_open;
714
715         cdev_init(&ptmx_cdev, &ptmx_fops);
716         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
717             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
718                 panic("Couldn't register /dev/ptmx driver\n");
719         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
720 }
721
722 #else
723 static inline void unix98_pty_init(void) { }
724 #endif
725
726 static int __init pty_init(void)
727 {
728         legacy_pty_init();
729         unix98_pty_init();
730         return 0;
731 }
732 module_init(pty_init);