Loading...
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
34static struct tty_driver *ptm_driver;
35static struct tty_driver *pts_driver;
36#endif
37
38static 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 */
78static 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
93static 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
113static 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
140static 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
155static int pty_chars_in_buffer(struct tty_struct *tty)
156{
157 return 0;
158}
159
160/* Set the lock flag on a pty */
161static 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 */
174static 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
190static 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
206static 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;
224out:
225 return retval;
226}
227
228static 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
244int 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 */
277done:
278 mutex_unlock(&tty->termios_mutex);
279 return 0;
280}
281
282/* Traditional BSD devices */
283#ifdef CONFIG_LEGACY_PTYS
284
285static 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;
326err_free_termios:
327 tty_free_termios(tty);
328err_deinit_tty:
329 deinitialize_tty_struct(o_tty);
330 module_put(o_tty->driver->owner);
331err_free_tty:
332 free_tty_struct(o_tty);
333 return retval;
334}
335
336static 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
348static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
349module_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 */
355static 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
369static 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
382static 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
437static 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 */
446int pty_limit = NR_UNIX98_PTY_DEFAULT;
447static int pty_limit_min;
448static int pty_limit_max = NR_UNIX98_PTY_MAX;
449static int tty_count;
450static int pty_count;
451
452static inline void pty_inc_count(void)
453{
454 pty_count = (++tty_count) / 2;
455}
456
457static inline void pty_dec_count(void)
458{
459 pty_count = (--tty_count) / 2;
460}
461
462static struct cdev ptmx_cdev;
463
464static 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
483static struct ctl_table pty_kern_table[] = {
484 {
485 .procname = "pty",
486 .mode = 0555,
487 .child = pty_table,
488 },
489 {}
490};
491
492static struct ctl_table pty_root_table[] = {
493 {
494 .procname = "kernel",
495 .mode = 0555,
496 .child = pty_kern_table,
497 },
498 {}
499};
500
501
502static 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
526static 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
544static 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
554static 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
564static 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;
606err_free_mem:
607 deinitialize_tty_struct(o_tty);
608 kfree(o_tty->termios);
609 kfree(tty->termios);
610 module_put(o_tty->driver->owner);
611err_free_tty:
612 free_tty_struct(o_tty);
613 return -ENOMEM;
614}
615
616static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
617{
618 pty_dec_count();
619}
620
621static 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
638static 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
665static 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 /* find a device that is not in use. */
674 tty_lock();
675 index = devpts_new_index(inode);
676 tty_unlock();
677 if (index < 0)
678 return index;
679
680 mutex_lock(&tty_mutex);
681 tty_lock();
682 tty = tty_init_dev(ptm_driver, index, 1);
683 mutex_unlock(&tty_mutex);
684
685 if (IS_ERR(tty)) {
686 retval = PTR_ERR(tty);
687 goto out;
688 }
689
690 set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
691
692 retval = tty_add_file(tty, filp);
693 if (retval)
694 goto out;
695
696 retval = devpts_pty_new(inode, tty->link);
697 if (retval)
698 goto out1;
699
700 retval = ptm_driver->ops->open(tty, filp);
701 if (retval)
702 goto out2;
703out1:
704 tty_unlock();
705 return retval;
706out2:
707 tty_unlock();
708 tty_release(inode, filp);
709 return retval;
710out:
711 devpts_kill_index(inode, index);
712 tty_unlock();
713 return retval;
714}
715
716static struct file_operations ptmx_fops;
717
718static void __init unix98_pty_init(void)
719{
720 ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
721 if (!ptm_driver)
722 panic("Couldn't allocate Unix98 ptm driver");
723 pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
724 if (!pts_driver)
725 panic("Couldn't allocate Unix98 pts driver");
726
727 ptm_driver->owner = THIS_MODULE;
728 ptm_driver->driver_name = "pty_master";
729 ptm_driver->name = "ptm";
730 ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
731 ptm_driver->minor_start = 0;
732 ptm_driver->type = TTY_DRIVER_TYPE_PTY;
733 ptm_driver->subtype = PTY_TYPE_MASTER;
734 ptm_driver->init_termios = tty_std_termios;
735 ptm_driver->init_termios.c_iflag = 0;
736 ptm_driver->init_termios.c_oflag = 0;
737 ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
738 ptm_driver->init_termios.c_lflag = 0;
739 ptm_driver->init_termios.c_ispeed = 38400;
740 ptm_driver->init_termios.c_ospeed = 38400;
741 ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
742 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
743 ptm_driver->other = pts_driver;
744 tty_set_operations(ptm_driver, &ptm_unix98_ops);
745
746 pts_driver->owner = THIS_MODULE;
747 pts_driver->driver_name = "pty_slave";
748 pts_driver->name = "pts";
749 pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
750 pts_driver->minor_start = 0;
751 pts_driver->type = TTY_DRIVER_TYPE_PTY;
752 pts_driver->subtype = PTY_TYPE_SLAVE;
753 pts_driver->init_termios = tty_std_termios;
754 pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
755 pts_driver->init_termios.c_ispeed = 38400;
756 pts_driver->init_termios.c_ospeed = 38400;
757 pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
758 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
759 pts_driver->other = ptm_driver;
760 tty_set_operations(pts_driver, &pty_unix98_ops);
761
762 if (tty_register_driver(ptm_driver))
763 panic("Couldn't register Unix98 ptm driver");
764 if (tty_register_driver(pts_driver))
765 panic("Couldn't register Unix98 pts driver");
766
767 register_sysctl_table(pty_root_table);
768
769 /* Now create the /dev/ptmx special device */
770 tty_default_fops(&ptmx_fops);
771 ptmx_fops.open = ptmx_open;
772
773 cdev_init(&ptmx_cdev, &ptmx_fops);
774 if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
775 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
776 panic("Couldn't register /dev/ptmx driver\n");
777 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
778}
779
780#else
781static inline void unix98_pty_init(void) { }
782#endif
783
784static int __init pty_init(void)
785{
786 legacy_pty_init();
787 unix98_pty_init();
788 return 0;
789}
790module_init(pty_init);
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 */
8
9#include <linux/module.h>
10
11#include <linux/errno.h>
12#include <linux/interrupt.h>
13#include <linux/tty.h>
14#include <linux/tty_flip.h>
15#include <linux/fcntl.h>
16#include <linux/sched.h>
17#include <linux/string.h>
18#include <linux/major.h>
19#include <linux/mm.h>
20#include <linux/init.h>
21#include <linux/device.h>
22#include <linux/uaccess.h>
23#include <linux/bitops.h>
24#include <linux/devpts_fs.h>
25#include <linux/slab.h>
26#include <linux/mutex.h>
27
28
29#ifdef CONFIG_UNIX98_PTYS
30static struct tty_driver *ptm_driver;
31static struct tty_driver *pts_driver;
32static DEFINE_MUTEX(devpts_mutex);
33#endif
34
35static void pty_close(struct tty_struct *tty, struct file *filp)
36{
37 BUG_ON(!tty);
38 if (tty->driver->subtype == PTY_TYPE_MASTER)
39 WARN_ON(tty->count > 1);
40 else {
41 if (test_bit(TTY_IO_ERROR, &tty->flags))
42 return;
43 if (tty->count > 2)
44 return;
45 }
46 set_bit(TTY_IO_ERROR, &tty->flags);
47 wake_up_interruptible(&tty->read_wait);
48 wake_up_interruptible(&tty->write_wait);
49 tty->packet = 0;
50 /* Review - krefs on tty_link ?? */
51 if (!tty->link)
52 return;
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 mutex_lock(&devpts_mutex);
61 if (tty->link->driver_data)
62 devpts_pty_kill(tty->link->driver_data);
63 mutex_unlock(&devpts_mutex);
64 }
65#endif
66 tty_unlock(tty);
67 tty_vhangup(tty->link);
68 tty_lock(tty);
69 }
70}
71
72/*
73 * The unthrottle routine is called by the line discipline to signal
74 * that it can receive more characters. For PTY's, the TTY_THROTTLED
75 * flag is always set, to force the line discipline to always call the
76 * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
77 * characters in the queue. This is necessary since each time this
78 * happens, we need to wake up any sleeping processes that could be
79 * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
80 * for the pty buffer to be drained.
81 */
82static void pty_unthrottle(struct tty_struct *tty)
83{
84 tty_wakeup(tty->link);
85 set_bit(TTY_THROTTLED, &tty->flags);
86}
87
88/**
89 * pty_space - report space left for writing
90 * @to: tty we are writing into
91 *
92 * Limit the buffer space used by ptys to 8k.
93 */
94
95static int pty_space(struct tty_struct *to)
96{
97 int n = tty_buffer_space_avail(to->port);
98 return min(n, 8192);
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
113static 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->port, buf, c);
123 /* And shovel */
124 if (c)
125 tty_flip_buffer_push(to->port);
126 }
127 return c;
128}
129
130/**
131 * pty_write_room - write space
132 * @tty: tty we are writing from
133 *
134 * Report how many bytes the ldisc can send into the queue for
135 * the other device.
136 */
137
138static int pty_write_room(struct tty_struct *tty)
139{
140 if (tty->stopped)
141 return 0;
142 return pty_space(tty->link);
143}
144
145/**
146 * pty_chars_in_buffer - characters currently in our tx queue
147 * @tty: our tty
148 *
149 * Report how much we have in the transmit queue. As everything is
150 * instantly at the other end this is easy to implement.
151 */
152
153static int pty_chars_in_buffer(struct tty_struct *tty)
154{
155 return 0;
156}
157
158/* Set the lock flag on a pty */
159static int pty_set_lock(struct tty_struct *tty, int __user *arg)
160{
161 int val;
162 if (get_user(val, arg))
163 return -EFAULT;
164 if (val)
165 set_bit(TTY_PTY_LOCK, &tty->flags);
166 else
167 clear_bit(TTY_PTY_LOCK, &tty->flags);
168 return 0;
169}
170
171static int pty_get_lock(struct tty_struct *tty, int __user *arg)
172{
173 int locked = test_bit(TTY_PTY_LOCK, &tty->flags);
174 return put_user(locked, arg);
175}
176
177/* Set the packet mode on a pty */
178static int pty_set_pktmode(struct tty_struct *tty, int __user *arg)
179{
180 unsigned long flags;
181 int pktmode;
182
183 if (get_user(pktmode, arg))
184 return -EFAULT;
185
186 spin_lock_irqsave(&tty->ctrl_lock, flags);
187 if (pktmode) {
188 if (!tty->packet) {
189 tty->packet = 1;
190 tty->link->ctrl_status = 0;
191 }
192 } else
193 tty->packet = 0;
194 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
195
196 return 0;
197}
198
199/* Get the packet mode of a pty */
200static int pty_get_pktmode(struct tty_struct *tty, int __user *arg)
201{
202 int pktmode = tty->packet;
203 return put_user(pktmode, arg);
204}
205
206/* Send a signal to the slave */
207static int pty_signal(struct tty_struct *tty, int sig)
208{
209 unsigned long flags;
210 struct pid *pgrp;
211
212 if (tty->link) {
213 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
214 pgrp = get_pid(tty->link->pgrp);
215 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
216
217 kill_pgrp(pgrp, sig, 1);
218 put_pid(pgrp);
219 }
220 return 0;
221}
222
223static void pty_flush_buffer(struct tty_struct *tty)
224{
225 struct tty_struct *to = tty->link;
226 unsigned long flags;
227
228 if (!to)
229 return;
230 /* tty_buffer_flush(to); FIXME */
231 if (to->packet) {
232 spin_lock_irqsave(&tty->ctrl_lock, flags);
233 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
234 wake_up_interruptible(&to->read_wait);
235 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
236 }
237}
238
239static int pty_open(struct tty_struct *tty, struct file *filp)
240{
241 if (!tty || !tty->link)
242 return -ENODEV;
243
244 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
245 goto out;
246 if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
247 goto out;
248 if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1)
249 goto out;
250
251 clear_bit(TTY_IO_ERROR, &tty->flags);
252 clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
253 set_bit(TTY_THROTTLED, &tty->flags);
254 return 0;
255
256out:
257 set_bit(TTY_IO_ERROR, &tty->flags);
258 return -EIO;
259}
260
261static void pty_set_termios(struct tty_struct *tty,
262 struct ktermios *old_termios)
263{
264 tty->termios.c_cflag &= ~(CSIZE | PARENB);
265 tty->termios.c_cflag |= (CS8 | CREAD);
266}
267
268/**
269 * pty_do_resize - resize event
270 * @tty: tty being resized
271 * @ws: window size being set.
272 *
273 * Update the termios variables and send the necessary signals to
274 * peform a terminal resize correctly
275 */
276
277static int pty_resize(struct tty_struct *tty, struct winsize *ws)
278{
279 struct pid *pgrp, *rpgrp;
280 unsigned long flags;
281 struct tty_struct *pty = tty->link;
282
283 /* For a PTY we need to lock the tty side */
284 mutex_lock(&tty->winsize_mutex);
285 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
286 goto done;
287
288 /* Get the PID values and reference them so we can
289 avoid holding the tty ctrl lock while sending signals.
290 We need to lock these individually however. */
291
292 spin_lock_irqsave(&tty->ctrl_lock, flags);
293 pgrp = get_pid(tty->pgrp);
294 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
295
296 spin_lock_irqsave(&pty->ctrl_lock, flags);
297 rpgrp = get_pid(pty->pgrp);
298 spin_unlock_irqrestore(&pty->ctrl_lock, flags);
299
300 if (pgrp)
301 kill_pgrp(pgrp, SIGWINCH, 1);
302 if (rpgrp != pgrp && rpgrp)
303 kill_pgrp(rpgrp, SIGWINCH, 1);
304
305 put_pid(pgrp);
306 put_pid(rpgrp);
307
308 tty->winsize = *ws;
309 pty->winsize = *ws; /* Never used so will go away soon */
310done:
311 mutex_unlock(&tty->winsize_mutex);
312 return 0;
313}
314
315/**
316 * pty_common_install - set up the pty pair
317 * @driver: the pty driver
318 * @tty: the tty being instantiated
319 * @bool: legacy, true if this is BSD style
320 *
321 * Perform the initial set up for the tty/pty pair. Called from the
322 * tty layer when the port is first opened.
323 *
324 * Locking: the caller must hold the tty_mutex
325 */
326static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
327 bool legacy)
328{
329 struct tty_struct *o_tty;
330 struct tty_port *ports[2];
331 int idx = tty->index;
332 int retval = -ENOMEM;
333
334 o_tty = alloc_tty_struct();
335 if (!o_tty)
336 goto err;
337 ports[0] = kmalloc(sizeof **ports, GFP_KERNEL);
338 ports[1] = kmalloc(sizeof **ports, GFP_KERNEL);
339 if (!ports[0] || !ports[1])
340 goto err_free_tty;
341 if (!try_module_get(driver->other->owner)) {
342 /* This cannot in fact currently happen */
343 goto err_free_tty;
344 }
345 initialize_tty_struct(o_tty, driver->other, idx);
346
347 if (legacy) {
348 /* We always use new tty termios data so we can do this
349 the easy way .. */
350 retval = tty_init_termios(tty);
351 if (retval)
352 goto err_deinit_tty;
353
354 retval = tty_init_termios(o_tty);
355 if (retval)
356 goto err_free_termios;
357
358 driver->other->ttys[idx] = o_tty;
359 driver->ttys[idx] = tty;
360 } else {
361 memset(&tty->termios_locked, 0, sizeof(tty->termios_locked));
362 tty->termios = driver->init_termios;
363 memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked));
364 o_tty->termios = driver->other->init_termios;
365 }
366
367 /*
368 * Everything allocated ... set up the o_tty structure.
369 */
370 tty_driver_kref_get(driver->other);
371 if (driver->subtype == PTY_TYPE_MASTER)
372 o_tty->count++;
373 /* Establish the links in both directions */
374 tty->link = o_tty;
375 o_tty->link = tty;
376 tty_port_init(ports[0]);
377 tty_port_init(ports[1]);
378 o_tty->port = ports[0];
379 tty->port = ports[1];
380 o_tty->port->itty = o_tty;
381
382 tty_driver_kref_get(driver);
383 tty->count++;
384 return 0;
385err_free_termios:
386 if (legacy)
387 tty_free_termios(tty);
388err_deinit_tty:
389 deinitialize_tty_struct(o_tty);
390 module_put(o_tty->driver->owner);
391err_free_tty:
392 kfree(ports[0]);
393 kfree(ports[1]);
394 free_tty_struct(o_tty);
395err:
396 return retval;
397}
398
399static void pty_cleanup(struct tty_struct *tty)
400{
401 tty_port_put(tty->port);
402}
403
404/* Traditional BSD devices */
405#ifdef CONFIG_LEGACY_PTYS
406
407static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
408{
409 return pty_common_install(driver, tty, true);
410}
411
412static void pty_remove(struct tty_driver *driver, struct tty_struct *tty)
413{
414 struct tty_struct *pair = tty->link;
415 driver->ttys[tty->index] = NULL;
416 if (pair)
417 pair->driver->ttys[pair->index] = NULL;
418}
419
420static int pty_bsd_ioctl(struct tty_struct *tty,
421 unsigned int cmd, unsigned long arg)
422{
423 switch (cmd) {
424 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
425 return pty_set_lock(tty, (int __user *) arg);
426 case TIOCGPTLCK: /* Get PT Lock status */
427 return pty_get_lock(tty, (int __user *)arg);
428 case TIOCPKT: /* Set PT packet mode */
429 return pty_set_pktmode(tty, (int __user *)arg);
430 case TIOCGPKT: /* Get PT packet mode */
431 return pty_get_pktmode(tty, (int __user *)arg);
432 case TIOCSIG: /* Send signal to other side of pty */
433 return pty_signal(tty, (int) arg);
434 case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */
435 return -EINVAL;
436 }
437 return -ENOIOCTLCMD;
438}
439
440static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
441module_param(legacy_count, int, 0);
442
443/*
444 * The master side of a pty can do TIOCSPTLCK and thus
445 * has pty_bsd_ioctl.
446 */
447static const struct tty_operations master_pty_ops_bsd = {
448 .install = pty_install,
449 .open = pty_open,
450 .close = pty_close,
451 .write = pty_write,
452 .write_room = pty_write_room,
453 .flush_buffer = pty_flush_buffer,
454 .chars_in_buffer = pty_chars_in_buffer,
455 .unthrottle = pty_unthrottle,
456 .set_termios = pty_set_termios,
457 .ioctl = pty_bsd_ioctl,
458 .cleanup = pty_cleanup,
459 .resize = pty_resize,
460 .remove = pty_remove
461};
462
463static const struct tty_operations slave_pty_ops_bsd = {
464 .install = pty_install,
465 .open = pty_open,
466 .close = pty_close,
467 .write = pty_write,
468 .write_room = pty_write_room,
469 .flush_buffer = pty_flush_buffer,
470 .chars_in_buffer = pty_chars_in_buffer,
471 .unthrottle = pty_unthrottle,
472 .set_termios = pty_set_termios,
473 .cleanup = pty_cleanup,
474 .resize = pty_resize,
475 .remove = pty_remove
476};
477
478static void __init legacy_pty_init(void)
479{
480 struct tty_driver *pty_driver, *pty_slave_driver;
481
482 if (legacy_count <= 0)
483 return;
484
485 pty_driver = tty_alloc_driver(legacy_count,
486 TTY_DRIVER_RESET_TERMIOS |
487 TTY_DRIVER_REAL_RAW |
488 TTY_DRIVER_DYNAMIC_ALLOC);
489 if (IS_ERR(pty_driver))
490 panic("Couldn't allocate pty driver");
491
492 pty_slave_driver = tty_alloc_driver(legacy_count,
493 TTY_DRIVER_RESET_TERMIOS |
494 TTY_DRIVER_REAL_RAW |
495 TTY_DRIVER_DYNAMIC_ALLOC);
496 if (IS_ERR(pty_slave_driver))
497 panic("Couldn't allocate pty slave driver");
498
499 pty_driver->driver_name = "pty_master";
500 pty_driver->name = "pty";
501 pty_driver->major = PTY_MASTER_MAJOR;
502 pty_driver->minor_start = 0;
503 pty_driver->type = TTY_DRIVER_TYPE_PTY;
504 pty_driver->subtype = PTY_TYPE_MASTER;
505 pty_driver->init_termios = tty_std_termios;
506 pty_driver->init_termios.c_iflag = 0;
507 pty_driver->init_termios.c_oflag = 0;
508 pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
509 pty_driver->init_termios.c_lflag = 0;
510 pty_driver->init_termios.c_ispeed = 38400;
511 pty_driver->init_termios.c_ospeed = 38400;
512 pty_driver->other = pty_slave_driver;
513 tty_set_operations(pty_driver, &master_pty_ops_bsd);
514
515 pty_slave_driver->driver_name = "pty_slave";
516 pty_slave_driver->name = "ttyp";
517 pty_slave_driver->major = PTY_SLAVE_MAJOR;
518 pty_slave_driver->minor_start = 0;
519 pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
520 pty_slave_driver->subtype = PTY_TYPE_SLAVE;
521 pty_slave_driver->init_termios = tty_std_termios;
522 pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
523 pty_slave_driver->init_termios.c_ispeed = 38400;
524 pty_slave_driver->init_termios.c_ospeed = 38400;
525 pty_slave_driver->other = pty_driver;
526 tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
527
528 if (tty_register_driver(pty_driver))
529 panic("Couldn't register pty driver");
530 if (tty_register_driver(pty_slave_driver))
531 panic("Couldn't register pty slave driver");
532}
533#else
534static inline void legacy_pty_init(void) { }
535#endif
536
537/* Unix98 devices */
538#ifdef CONFIG_UNIX98_PTYS
539
540static struct cdev ptmx_cdev;
541
542static int pty_unix98_ioctl(struct tty_struct *tty,
543 unsigned int cmd, unsigned long arg)
544{
545 switch (cmd) {
546 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
547 return pty_set_lock(tty, (int __user *)arg);
548 case TIOCGPTLCK: /* Get PT Lock status */
549 return pty_get_lock(tty, (int __user *)arg);
550 case TIOCPKT: /* Set PT packet mode */
551 return pty_set_pktmode(tty, (int __user *)arg);
552 case TIOCGPKT: /* Get PT packet mode */
553 return pty_get_pktmode(tty, (int __user *)arg);
554 case TIOCGPTN: /* Get PT Number */
555 return put_user(tty->index, (unsigned int __user *)arg);
556 case TIOCSIG: /* Send signal to other side of pty */
557 return pty_signal(tty, (int) arg);
558 }
559
560 return -ENOIOCTLCMD;
561}
562
563/**
564 * ptm_unix98_lookup - find a pty master
565 * @driver: ptm driver
566 * @idx: tty index
567 *
568 * Look up a pty master device. Called under the tty_mutex for now.
569 * This provides our locking.
570 */
571
572static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
573 struct inode *ptm_inode, int idx)
574{
575 /* Master must be open via /dev/ptmx */
576 return ERR_PTR(-EIO);
577}
578
579/**
580 * pts_unix98_lookup - find a pty slave
581 * @driver: pts driver
582 * @idx: tty index
583 *
584 * Look up a pty master device. Called under the tty_mutex for now.
585 * This provides our locking for the tty pointer.
586 */
587
588static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
589 struct inode *pts_inode, int idx)
590{
591 struct tty_struct *tty;
592
593 mutex_lock(&devpts_mutex);
594 tty = devpts_get_priv(pts_inode);
595 mutex_unlock(&devpts_mutex);
596 /* Master must be open before slave */
597 if (!tty)
598 return ERR_PTR(-EIO);
599 return tty;
600}
601
602/* We have no need to install and remove our tty objects as devpts does all
603 the work for us */
604
605static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
606{
607 return pty_common_install(driver, tty, false);
608}
609
610static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
611{
612}
613
614/* this is called once with whichever end is closed last */
615static void pty_unix98_shutdown(struct tty_struct *tty)
616{
617 devpts_kill_index(tty->driver_data, tty->index);
618}
619
620static const struct tty_operations ptm_unix98_ops = {
621 .lookup = ptm_unix98_lookup,
622 .install = pty_unix98_install,
623 .remove = pty_unix98_remove,
624 .open = pty_open,
625 .close = pty_close,
626 .write = pty_write,
627 .write_room = pty_write_room,
628 .flush_buffer = pty_flush_buffer,
629 .chars_in_buffer = pty_chars_in_buffer,
630 .unthrottle = pty_unthrottle,
631 .set_termios = pty_set_termios,
632 .ioctl = pty_unix98_ioctl,
633 .resize = pty_resize,
634 .shutdown = pty_unix98_shutdown,
635 .cleanup = pty_cleanup
636};
637
638static 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 .cleanup = pty_cleanup,
652};
653
654/**
655 * ptmx_open - open a unix 98 pty master
656 * @inode: inode of device file
657 * @filp: file pointer to tty
658 *
659 * Allocate a unix98 pty master device from the ptmx driver.
660 *
661 * Locking: tty_mutex protects the init_dev work. tty->count should
662 * protect the rest.
663 * allocated_ptys_lock handles the list of free pty numbers
664 */
665
666static int ptmx_open(struct inode *inode, struct file *filp)
667{
668 struct tty_struct *tty;
669 struct inode *slave_inode;
670 int retval;
671 int index;
672
673 nonseekable_open(inode, filp);
674
675 /* We refuse fsnotify events on ptmx, since it's a shared resource */
676 filp->f_mode |= FMODE_NONOTIFY;
677
678 retval = tty_alloc_file(filp);
679 if (retval)
680 return retval;
681
682 /* find a device that is not in use. */
683 mutex_lock(&devpts_mutex);
684 index = devpts_new_index(inode);
685 if (index < 0) {
686 retval = index;
687 mutex_unlock(&devpts_mutex);
688 goto err_file;
689 }
690
691 mutex_unlock(&devpts_mutex);
692
693 mutex_lock(&tty_mutex);
694 tty = tty_init_dev(ptm_driver, index);
695
696 if (IS_ERR(tty)) {
697 retval = PTR_ERR(tty);
698 goto out;
699 }
700
701 /* The tty returned here is locked so we can safely
702 drop the mutex */
703 mutex_unlock(&tty_mutex);
704
705 set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
706 tty->driver_data = inode;
707
708 tty_add_file(tty, filp);
709
710 slave_inode = devpts_pty_new(inode,
711 MKDEV(UNIX98_PTY_SLAVE_MAJOR, index), index,
712 tty->link);
713 if (IS_ERR(slave_inode)) {
714 retval = PTR_ERR(slave_inode);
715 goto err_release;
716 }
717 tty->link->driver_data = slave_inode;
718
719 retval = ptm_driver->ops->open(tty, filp);
720 if (retval)
721 goto err_release;
722
723 tty_unlock(tty);
724 return 0;
725err_release:
726 tty_unlock(tty);
727 tty_release(inode, filp);
728 return retval;
729out:
730 mutex_unlock(&tty_mutex);
731 devpts_kill_index(inode, index);
732err_file:
733 tty_free_file(filp);
734 return retval;
735}
736
737static struct file_operations ptmx_fops;
738
739static void __init unix98_pty_init(void)
740{
741 ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
742 TTY_DRIVER_RESET_TERMIOS |
743 TTY_DRIVER_REAL_RAW |
744 TTY_DRIVER_DYNAMIC_DEV |
745 TTY_DRIVER_DEVPTS_MEM |
746 TTY_DRIVER_DYNAMIC_ALLOC);
747 if (IS_ERR(ptm_driver))
748 panic("Couldn't allocate Unix98 ptm driver");
749 pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
750 TTY_DRIVER_RESET_TERMIOS |
751 TTY_DRIVER_REAL_RAW |
752 TTY_DRIVER_DYNAMIC_DEV |
753 TTY_DRIVER_DEVPTS_MEM |
754 TTY_DRIVER_DYNAMIC_ALLOC);
755 if (IS_ERR(pts_driver))
756 panic("Couldn't allocate Unix98 pts driver");
757
758 ptm_driver->driver_name = "pty_master";
759 ptm_driver->name = "ptm";
760 ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
761 ptm_driver->minor_start = 0;
762 ptm_driver->type = TTY_DRIVER_TYPE_PTY;
763 ptm_driver->subtype = PTY_TYPE_MASTER;
764 ptm_driver->init_termios = tty_std_termios;
765 ptm_driver->init_termios.c_iflag = 0;
766 ptm_driver->init_termios.c_oflag = 0;
767 ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
768 ptm_driver->init_termios.c_lflag = 0;
769 ptm_driver->init_termios.c_ispeed = 38400;
770 ptm_driver->init_termios.c_ospeed = 38400;
771 ptm_driver->other = pts_driver;
772 tty_set_operations(ptm_driver, &ptm_unix98_ops);
773
774 pts_driver->driver_name = "pty_slave";
775 pts_driver->name = "pts";
776 pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
777 pts_driver->minor_start = 0;
778 pts_driver->type = TTY_DRIVER_TYPE_PTY;
779 pts_driver->subtype = PTY_TYPE_SLAVE;
780 pts_driver->init_termios = tty_std_termios;
781 pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
782 pts_driver->init_termios.c_ispeed = 38400;
783 pts_driver->init_termios.c_ospeed = 38400;
784 pts_driver->other = ptm_driver;
785 tty_set_operations(pts_driver, &pty_unix98_ops);
786
787 if (tty_register_driver(ptm_driver))
788 panic("Couldn't register Unix98 ptm driver");
789 if (tty_register_driver(pts_driver))
790 panic("Couldn't register Unix98 pts driver");
791
792 /* Now create the /dev/ptmx special device */
793 tty_default_fops(&ptmx_fops);
794 ptmx_fops.open = ptmx_open;
795
796 cdev_init(&ptmx_cdev, &ptmx_fops);
797 if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
798 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
799 panic("Couldn't register /dev/ptmx driver");
800 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
801}
802
803#else
804static inline void unix98_pty_init(void) { }
805#endif
806
807static int __init pty_init(void)
808{
809 legacy_pty_init();
810 unix98_pty_init();
811 return 0;
812}
813module_init(pty_init);