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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 |
30 | static struct tty_driver *ptm_driver; |
31 | static struct tty_driver *pts_driver; |
32 | static DEFINE_MUTEX(devpts_mutex); |
33 | #endif |
34 | |
35 | static 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 | */ |
82 | static 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 | * The tty buffers allow 64K but we sneak a peak and clip at 8K this |
93 | * allows a lot of overspill room for echo and other fun messes to |
94 | * be handled properly |
95 | */ |
96 | |
97 | static int pty_space(struct tty_struct *to) |
98 | { |
99 | int n = 8192 - to->port->buf.memory_used; |
100 | if (n < 0) |
101 | return 0; |
102 | return n; |
103 | } |
104 | |
105 | /** |
106 | * pty_write - write to a pty |
107 | * @tty: the tty we write from |
108 | * @buf: kernel buffer of data |
109 | * @count: bytes to write |
110 | * |
111 | * Our "hardware" write method. Data is coming from the ldisc which |
112 | * may be in a non sleeping state. We simply throw this at the other |
113 | * end of the link as if we were an IRQ handler receiving stuff for |
114 | * the other side of the pty/tty pair. |
115 | */ |
116 | |
117 | static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c) |
118 | { |
119 | struct tty_struct *to = tty->link; |
120 | |
121 | if (tty->stopped) |
122 | return 0; |
123 | |
124 | if (c > 0) { |
125 | /* Stuff the data into the input queue of the other end */ |
126 | c = tty_insert_flip_string(to->port, buf, c); |
127 | /* And shovel */ |
128 | if (c) { |
129 | tty_flip_buffer_push(to->port); |
130 | tty_wakeup(tty); |
131 | } |
132 | } |
133 | return c; |
134 | } |
135 | |
136 | /** |
137 | * pty_write_room - write space |
138 | * @tty: tty we are writing from |
139 | * |
140 | * Report how many bytes the ldisc can send into the queue for |
141 | * the other device. |
142 | */ |
143 | |
144 | static int pty_write_room(struct tty_struct *tty) |
145 | { |
146 | if (tty->stopped) |
147 | return 0; |
148 | return pty_space(tty->link); |
149 | } |
150 | |
151 | /** |
152 | * pty_chars_in_buffer - characters currently in our tx queue |
153 | * @tty: our tty |
154 | * |
155 | * Report how much we have in the transmit queue. As everything is |
156 | * instantly at the other end this is easy to implement. |
157 | */ |
158 | |
159 | static int pty_chars_in_buffer(struct tty_struct *tty) |
160 | { |
161 | return 0; |
162 | } |
163 | |
164 | /* Set the lock flag on a pty */ |
165 | static int pty_set_lock(struct tty_struct *tty, int __user *arg) |
166 | { |
167 | int val; |
168 | if (get_user(val, arg)) |
169 | return -EFAULT; |
170 | if (val) |
171 | set_bit(TTY_PTY_LOCK, &tty->flags); |
172 | else |
173 | clear_bit(TTY_PTY_LOCK, &tty->flags); |
174 | return 0; |
175 | } |
176 | |
177 | static int pty_get_lock(struct tty_struct *tty, int __user *arg) |
178 | { |
179 | int locked = test_bit(TTY_PTY_LOCK, &tty->flags); |
180 | return put_user(locked, arg); |
181 | } |
182 | |
183 | /* Set the packet mode on a pty */ |
184 | static int pty_set_pktmode(struct tty_struct *tty, int __user *arg) |
185 | { |
186 | unsigned long flags; |
187 | int pktmode; |
188 | |
189 | if (get_user(pktmode, arg)) |
190 | return -EFAULT; |
191 | |
192 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
193 | if (pktmode) { |
194 | if (!tty->packet) { |
195 | tty->packet = 1; |
196 | tty->link->ctrl_status = 0; |
197 | } |
198 | } else |
199 | tty->packet = 0; |
200 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
201 | |
202 | return 0; |
203 | } |
204 | |
205 | /* Get the packet mode of a pty */ |
206 | static int pty_get_pktmode(struct tty_struct *tty, int __user *arg) |
207 | { |
208 | int pktmode = tty->packet; |
209 | return put_user(pktmode, arg); |
210 | } |
211 | |
212 | /* Send a signal to the slave */ |
213 | static int pty_signal(struct tty_struct *tty, int sig) |
214 | { |
215 | unsigned long flags; |
216 | struct pid *pgrp; |
217 | |
218 | if (tty->link) { |
219 | spin_lock_irqsave(&tty->link->ctrl_lock, flags); |
220 | pgrp = get_pid(tty->link->pgrp); |
221 | spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); |
222 | |
223 | kill_pgrp(pgrp, sig, 1); |
224 | put_pid(pgrp); |
225 | } |
226 | return 0; |
227 | } |
228 | |
229 | static void pty_flush_buffer(struct tty_struct *tty) |
230 | { |
231 | struct tty_struct *to = tty->link; |
232 | unsigned long flags; |
233 | |
234 | if (!to) |
235 | return; |
236 | /* tty_buffer_flush(to); FIXME */ |
237 | if (to->packet) { |
238 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
239 | tty->ctrl_status |= TIOCPKT_FLUSHWRITE; |
240 | wake_up_interruptible(&to->read_wait); |
241 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
242 | } |
243 | } |
244 | |
245 | static int pty_open(struct tty_struct *tty, struct file *filp) |
246 | { |
247 | int retval = -ENODEV; |
248 | |
249 | if (!tty || !tty->link) |
250 | goto out; |
251 | |
252 | set_bit(TTY_IO_ERROR, &tty->flags); |
253 | |
254 | retval = -EIO; |
255 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) |
256 | goto out; |
257 | if (test_bit(TTY_PTY_LOCK, &tty->link->flags)) |
258 | goto out; |
259 | if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1) |
260 | goto out; |
261 | |
262 | clear_bit(TTY_IO_ERROR, &tty->flags); |
263 | clear_bit(TTY_OTHER_CLOSED, &tty->link->flags); |
264 | set_bit(TTY_THROTTLED, &tty->flags); |
265 | retval = 0; |
266 | out: |
267 | return retval; |
268 | } |
269 | |
270 | static void pty_set_termios(struct tty_struct *tty, |
271 | struct ktermios *old_termios) |
272 | { |
273 | tty->termios.c_cflag &= ~(CSIZE | PARENB); |
274 | tty->termios.c_cflag |= (CS8 | CREAD); |
275 | } |
276 | |
277 | /** |
278 | * pty_do_resize - resize event |
279 | * @tty: tty being resized |
280 | * @ws: window size being set. |
281 | * |
282 | * Update the termios variables and send the necessary signals to |
283 | * peform a terminal resize correctly |
284 | */ |
285 | |
286 | static int pty_resize(struct tty_struct *tty, struct winsize *ws) |
287 | { |
288 | struct pid *pgrp, *rpgrp; |
289 | unsigned long flags; |
290 | struct tty_struct *pty = tty->link; |
291 | |
292 | /* For a PTY we need to lock the tty side */ |
293 | mutex_lock(&tty->termios_mutex); |
294 | if (!memcmp(ws, &tty->winsize, sizeof(*ws))) |
295 | goto done; |
296 | |
297 | /* Get the PID values and reference them so we can |
298 | avoid holding the tty ctrl lock while sending signals. |
299 | We need to lock these individually however. */ |
300 | |
301 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
302 | pgrp = get_pid(tty->pgrp); |
303 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
304 | |
305 | spin_lock_irqsave(&pty->ctrl_lock, flags); |
306 | rpgrp = get_pid(pty->pgrp); |
307 | spin_unlock_irqrestore(&pty->ctrl_lock, flags); |
308 | |
309 | if (pgrp) |
310 | kill_pgrp(pgrp, SIGWINCH, 1); |
311 | if (rpgrp != pgrp && rpgrp) |
312 | kill_pgrp(rpgrp, SIGWINCH, 1); |
313 | |
314 | put_pid(pgrp); |
315 | put_pid(rpgrp); |
316 | |
317 | tty->winsize = *ws; |
318 | pty->winsize = *ws; /* Never used so will go away soon */ |
319 | done: |
320 | mutex_unlock(&tty->termios_mutex); |
321 | return 0; |
322 | } |
323 | |
324 | /** |
325 | * pty_common_install - set up the pty pair |
326 | * @driver: the pty driver |
327 | * @tty: the tty being instantiated |
328 | * @bool: legacy, true if this is BSD style |
329 | * |
330 | * Perform the initial set up for the tty/pty pair. Called from the |
331 | * tty layer when the port is first opened. |
332 | * |
333 | * Locking: the caller must hold the tty_mutex |
334 | */ |
335 | static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, |
336 | bool legacy) |
337 | { |
338 | struct tty_struct *o_tty; |
339 | struct tty_port *ports[2]; |
340 | int idx = tty->index; |
341 | int retval = -ENOMEM; |
342 | |
343 | o_tty = alloc_tty_struct(); |
344 | if (!o_tty) |
345 | goto err; |
346 | ports[0] = kmalloc(sizeof **ports, GFP_KERNEL); |
347 | ports[1] = kmalloc(sizeof **ports, GFP_KERNEL); |
348 | if (!ports[0] || !ports[1]) |
349 | goto err_free_tty; |
350 | if (!try_module_get(driver->other->owner)) { |
351 | /* This cannot in fact currently happen */ |
352 | goto err_free_tty; |
353 | } |
354 | initialize_tty_struct(o_tty, driver->other, idx); |
355 | |
356 | if (legacy) { |
357 | /* We always use new tty termios data so we can do this |
358 | the easy way .. */ |
359 | retval = tty_init_termios(tty); |
360 | if (retval) |
361 | goto err_deinit_tty; |
362 | |
363 | retval = tty_init_termios(o_tty); |
364 | if (retval) |
365 | goto err_free_termios; |
366 | |
367 | driver->other->ttys[idx] = o_tty; |
368 | driver->ttys[idx] = tty; |
369 | } else { |
370 | memset(&tty->termios_locked, 0, sizeof(tty->termios_locked)); |
371 | tty->termios = driver->init_termios; |
372 | memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked)); |
373 | o_tty->termios = driver->other->init_termios; |
374 | } |
375 | |
376 | /* |
377 | * Everything allocated ... set up the o_tty structure. |
378 | */ |
379 | tty_driver_kref_get(driver->other); |
380 | if (driver->subtype == PTY_TYPE_MASTER) |
381 | o_tty->count++; |
382 | /* Establish the links in both directions */ |
383 | tty->link = o_tty; |
384 | o_tty->link = tty; |
385 | tty_port_init(ports[0]); |
386 | tty_port_init(ports[1]); |
387 | o_tty->port = ports[0]; |
388 | tty->port = ports[1]; |
389 | o_tty->port->itty = o_tty; |
390 | |
391 | tty_driver_kref_get(driver); |
392 | tty->count++; |
393 | return 0; |
394 | err_free_termios: |
395 | if (legacy) |
396 | tty_free_termios(tty); |
397 | err_deinit_tty: |
398 | deinitialize_tty_struct(o_tty); |
399 | module_put(o_tty->driver->owner); |
400 | err_free_tty: |
401 | kfree(ports[0]); |
402 | kfree(ports[1]); |
403 | free_tty_struct(o_tty); |
404 | err: |
405 | return retval; |
406 | } |
407 | |
408 | /* this is called once with whichever end is closed last */ |
409 | static void pty_unix98_shutdown(struct tty_struct *tty) |
410 | { |
411 | devpts_kill_index(tty->driver_data, tty->index); |
412 | } |
413 | |
414 | static void pty_cleanup(struct tty_struct *tty) |
415 | { |
416 | tty->port->itty = NULL; |
417 | tty_port_put(tty->port); |
418 | } |
419 | |
420 | /* Traditional BSD devices */ |
421 | #ifdef CONFIG_LEGACY_PTYS |
422 | |
423 | static int pty_install(struct tty_driver *driver, struct tty_struct *tty) |
424 | { |
425 | return pty_common_install(driver, tty, true); |
426 | } |
427 | |
428 | static void pty_remove(struct tty_driver *driver, struct tty_struct *tty) |
429 | { |
430 | struct tty_struct *pair = tty->link; |
431 | driver->ttys[tty->index] = NULL; |
432 | if (pair) |
433 | pair->driver->ttys[pair->index] = NULL; |
434 | } |
435 | |
436 | static int pty_bsd_ioctl(struct tty_struct *tty, |
437 | unsigned int cmd, unsigned long arg) |
438 | { |
439 | switch (cmd) { |
440 | case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ |
441 | return pty_set_lock(tty, (int __user *) arg); |
442 | case TIOCGPTLCK: /* Get PT Lock status */ |
443 | return pty_get_lock(tty, (int __user *)arg); |
444 | case TIOCPKT: /* Set PT packet mode */ |
445 | return pty_set_pktmode(tty, (int __user *)arg); |
446 | case TIOCGPKT: /* Get PT packet mode */ |
447 | return pty_get_pktmode(tty, (int __user *)arg); |
448 | case TIOCSIG: /* Send signal to other side of pty */ |
449 | return pty_signal(tty, (int) arg); |
450 | case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */ |
451 | return -EINVAL; |
452 | } |
453 | return -ENOIOCTLCMD; |
454 | } |
455 | |
456 | static int legacy_count = CONFIG_LEGACY_PTY_COUNT; |
457 | module_param(legacy_count, int, 0); |
458 | |
459 | /* |
460 | * The master side of a pty can do TIOCSPTLCK and thus |
461 | * has pty_bsd_ioctl. |
462 | */ |
463 | static const struct tty_operations master_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 | .ioctl = pty_bsd_ioctl, |
474 | .cleanup = pty_cleanup, |
475 | .resize = pty_resize, |
476 | .remove = pty_remove |
477 | }; |
478 | |
479 | static const struct tty_operations slave_pty_ops_bsd = { |
480 | .install = pty_install, |
481 | .open = pty_open, |
482 | .close = pty_close, |
483 | .write = pty_write, |
484 | .write_room = pty_write_room, |
485 | .flush_buffer = pty_flush_buffer, |
486 | .chars_in_buffer = pty_chars_in_buffer, |
487 | .unthrottle = pty_unthrottle, |
488 | .set_termios = pty_set_termios, |
489 | .cleanup = pty_cleanup, |
490 | .resize = pty_resize, |
491 | .remove = pty_remove |
492 | }; |
493 | |
494 | static void __init legacy_pty_init(void) |
495 | { |
496 | struct tty_driver *pty_driver, *pty_slave_driver; |
497 | |
498 | if (legacy_count <= 0) |
499 | return; |
500 | |
501 | pty_driver = tty_alloc_driver(legacy_count, |
502 | TTY_DRIVER_RESET_TERMIOS | |
503 | TTY_DRIVER_REAL_RAW | |
504 | TTY_DRIVER_DYNAMIC_ALLOC); |
505 | if (IS_ERR(pty_driver)) |
506 | panic("Couldn't allocate pty driver"); |
507 | |
508 | pty_slave_driver = tty_alloc_driver(legacy_count, |
509 | TTY_DRIVER_RESET_TERMIOS | |
510 | TTY_DRIVER_REAL_RAW | |
511 | TTY_DRIVER_DYNAMIC_ALLOC); |
512 | if (IS_ERR(pty_slave_driver)) |
513 | panic("Couldn't allocate pty slave driver"); |
514 | |
515 | pty_driver->driver_name = "pty_master"; |
516 | pty_driver->name = "pty"; |
517 | pty_driver->major = PTY_MASTER_MAJOR; |
518 | pty_driver->minor_start = 0; |
519 | pty_driver->type = TTY_DRIVER_TYPE_PTY; |
520 | pty_driver->subtype = PTY_TYPE_MASTER; |
521 | pty_driver->init_termios = tty_std_termios; |
522 | pty_driver->init_termios.c_iflag = 0; |
523 | pty_driver->init_termios.c_oflag = 0; |
524 | pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
525 | pty_driver->init_termios.c_lflag = 0; |
526 | pty_driver->init_termios.c_ispeed = 38400; |
527 | pty_driver->init_termios.c_ospeed = 38400; |
528 | pty_driver->other = pty_slave_driver; |
529 | tty_set_operations(pty_driver, &master_pty_ops_bsd); |
530 | |
531 | pty_slave_driver->driver_name = "pty_slave"; |
532 | pty_slave_driver->name = "ttyp"; |
533 | pty_slave_driver->major = PTY_SLAVE_MAJOR; |
534 | pty_slave_driver->minor_start = 0; |
535 | pty_slave_driver->type = TTY_DRIVER_TYPE_PTY; |
536 | pty_slave_driver->subtype = PTY_TYPE_SLAVE; |
537 | pty_slave_driver->init_termios = tty_std_termios; |
538 | pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
539 | pty_slave_driver->init_termios.c_ispeed = 38400; |
540 | pty_slave_driver->init_termios.c_ospeed = 38400; |
541 | pty_slave_driver->other = pty_driver; |
542 | tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd); |
543 | |
544 | if (tty_register_driver(pty_driver)) |
545 | panic("Couldn't register pty driver"); |
546 | if (tty_register_driver(pty_slave_driver)) |
547 | panic("Couldn't register pty slave driver"); |
548 | } |
549 | #else |
550 | static inline void legacy_pty_init(void) { } |
551 | #endif |
552 | |
553 | /* Unix98 devices */ |
554 | #ifdef CONFIG_UNIX98_PTYS |
555 | |
556 | static struct cdev ptmx_cdev; |
557 | |
558 | static int pty_unix98_ioctl(struct tty_struct *tty, |
559 | unsigned int cmd, unsigned long arg) |
560 | { |
561 | switch (cmd) { |
562 | case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ |
563 | return pty_set_lock(tty, (int __user *)arg); |
564 | case TIOCGPTLCK: /* Get PT Lock status */ |
565 | return pty_get_lock(tty, (int __user *)arg); |
566 | case TIOCPKT: /* Set PT packet mode */ |
567 | return pty_set_pktmode(tty, (int __user *)arg); |
568 | case TIOCGPKT: /* Get PT packet mode */ |
569 | return pty_get_pktmode(tty, (int __user *)arg); |
570 | case TIOCGPTN: /* Get PT Number */ |
571 | return put_user(tty->index, (unsigned int __user *)arg); |
572 | case TIOCSIG: /* Send signal to other side of pty */ |
573 | return pty_signal(tty, (int) arg); |
574 | } |
575 | |
576 | return -ENOIOCTLCMD; |
577 | } |
578 | |
579 | /** |
580 | * ptm_unix98_lookup - find a pty master |
581 | * @driver: ptm 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. |
586 | */ |
587 | |
588 | static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, |
589 | struct inode *ptm_inode, int idx) |
590 | { |
591 | /* Master must be open via /dev/ptmx */ |
592 | return ERR_PTR(-EIO); |
593 | } |
594 | |
595 | /** |
596 | * pts_unix98_lookup - find a pty slave |
597 | * @driver: pts driver |
598 | * @idx: tty index |
599 | * |
600 | * Look up a pty master device. Called under the tty_mutex for now. |
601 | * This provides our locking for the tty pointer. |
602 | */ |
603 | |
604 | static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, |
605 | struct inode *pts_inode, int idx) |
606 | { |
607 | struct tty_struct *tty; |
608 | |
609 | mutex_lock(&devpts_mutex); |
610 | tty = devpts_get_priv(pts_inode); |
611 | mutex_unlock(&devpts_mutex); |
612 | /* Master must be open before slave */ |
613 | if (!tty) |
614 | return ERR_PTR(-EIO); |
615 | return tty; |
616 | } |
617 | |
618 | /* We have no need to install and remove our tty objects as devpts does all |
619 | the work for us */ |
620 | |
621 | static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) |
622 | { |
623 | return pty_common_install(driver, tty, false); |
624 | } |
625 | |
626 | static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) |
627 | { |
628 | } |
629 | |
630 | static const struct tty_operations ptm_unix98_ops = { |
631 | .lookup = ptm_unix98_lookup, |
632 | .install = pty_unix98_install, |
633 | .remove = pty_unix98_remove, |
634 | .open = pty_open, |
635 | .close = pty_close, |
636 | .write = pty_write, |
637 | .write_room = pty_write_room, |
638 | .flush_buffer = pty_flush_buffer, |
639 | .chars_in_buffer = pty_chars_in_buffer, |
640 | .unthrottle = pty_unthrottle, |
641 | .set_termios = pty_set_termios, |
642 | .ioctl = pty_unix98_ioctl, |
643 | .resize = pty_resize, |
644 | .shutdown = pty_unix98_shutdown, |
645 | .cleanup = pty_cleanup |
646 | }; |
647 | |
648 | static const struct tty_operations pty_unix98_ops = { |
649 | .lookup = pts_unix98_lookup, |
650 | .install = pty_unix98_install, |
651 | .remove = pty_unix98_remove, |
652 | .open = pty_open, |
653 | .close = pty_close, |
654 | .write = pty_write, |
655 | .write_room = pty_write_room, |
656 | .flush_buffer = pty_flush_buffer, |
657 | .chars_in_buffer = pty_chars_in_buffer, |
658 | .unthrottle = pty_unthrottle, |
659 | .set_termios = pty_set_termios, |
660 | .shutdown = pty_unix98_shutdown, |
661 | .cleanup = pty_cleanup, |
662 | }; |
663 | |
664 | /** |
665 | * ptmx_open - open a unix 98 pty master |
666 | * @inode: inode of device file |
667 | * @filp: file pointer to tty |
668 | * |
669 | * Allocate a unix98 pty master device from the ptmx driver. |
670 | * |
671 | * Locking: tty_mutex protects the init_dev work. tty->count should |
672 | * protect the rest. |
673 | * allocated_ptys_lock handles the list of free pty numbers |
674 | */ |
675 | |
676 | static int ptmx_open(struct inode *inode, struct file *filp) |
677 | { |
678 | struct tty_struct *tty; |
679 | struct inode *slave_inode; |
680 | int retval; |
681 | int index; |
682 | |
683 | nonseekable_open(inode, filp); |
684 | |
685 | retval = tty_alloc_file(filp); |
686 | if (retval) |
687 | return retval; |
688 | |
689 | /* find a device that is not in use. */ |
690 | mutex_lock(&devpts_mutex); |
691 | index = devpts_new_index(inode); |
692 | if (index < 0) { |
693 | retval = index; |
694 | mutex_unlock(&devpts_mutex); |
695 | goto err_file; |
696 | } |
697 | |
698 | mutex_unlock(&devpts_mutex); |
699 | |
700 | mutex_lock(&tty_mutex); |
701 | tty = tty_init_dev(ptm_driver, index); |
702 | |
703 | if (IS_ERR(tty)) { |
704 | retval = PTR_ERR(tty); |
705 | goto out; |
706 | } |
707 | |
708 | /* The tty returned here is locked so we can safely |
709 | drop the mutex */ |
710 | mutex_unlock(&tty_mutex); |
711 | |
712 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ |
713 | tty->driver_data = inode; |
714 | |
715 | tty_add_file(tty, filp); |
716 | |
717 | slave_inode = devpts_pty_new(inode, |
718 | MKDEV(UNIX98_PTY_SLAVE_MAJOR, index), index, |
719 | tty->link); |
720 | if (IS_ERR(slave_inode)) { |
721 | retval = PTR_ERR(slave_inode); |
722 | goto err_release; |
723 | } |
724 | tty->link->driver_data = slave_inode; |
725 | |
726 | retval = ptm_driver->ops->open(tty, filp); |
727 | if (retval) |
728 | goto err_release; |
729 | |
730 | tty_unlock(tty); |
731 | return 0; |
732 | err_release: |
733 | tty_unlock(tty); |
734 | tty_release(inode, filp); |
735 | return retval; |
736 | out: |
737 | mutex_unlock(&tty_mutex); |
738 | devpts_kill_index(inode, index); |
739 | err_file: |
740 | tty_free_file(filp); |
741 | return retval; |
742 | } |
743 | |
744 | static struct file_operations ptmx_fops; |
745 | |
746 | static void __init unix98_pty_init(void) |
747 | { |
748 | ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, |
749 | TTY_DRIVER_RESET_TERMIOS | |
750 | TTY_DRIVER_REAL_RAW | |
751 | TTY_DRIVER_DYNAMIC_DEV | |
752 | TTY_DRIVER_DEVPTS_MEM | |
753 | TTY_DRIVER_DYNAMIC_ALLOC); |
754 | if (IS_ERR(ptm_driver)) |
755 | panic("Couldn't allocate Unix98 ptm driver"); |
756 | pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, |
757 | TTY_DRIVER_RESET_TERMIOS | |
758 | TTY_DRIVER_REAL_RAW | |
759 | TTY_DRIVER_DYNAMIC_DEV | |
760 | TTY_DRIVER_DEVPTS_MEM | |
761 | TTY_DRIVER_DYNAMIC_ALLOC); |
762 | if (IS_ERR(pts_driver)) |
763 | panic("Couldn't allocate Unix98 pts driver"); |
764 | |
765 | ptm_driver->driver_name = "pty_master"; |
766 | ptm_driver->name = "ptm"; |
767 | ptm_driver->major = UNIX98_PTY_MASTER_MAJOR; |
768 | ptm_driver->minor_start = 0; |
769 | ptm_driver->type = TTY_DRIVER_TYPE_PTY; |
770 | ptm_driver->subtype = PTY_TYPE_MASTER; |
771 | ptm_driver->init_termios = tty_std_termios; |
772 | ptm_driver->init_termios.c_iflag = 0; |
773 | ptm_driver->init_termios.c_oflag = 0; |
774 | ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
775 | ptm_driver->init_termios.c_lflag = 0; |
776 | ptm_driver->init_termios.c_ispeed = 38400; |
777 | ptm_driver->init_termios.c_ospeed = 38400; |
778 | ptm_driver->other = pts_driver; |
779 | tty_set_operations(ptm_driver, &ptm_unix98_ops); |
780 | |
781 | pts_driver->driver_name = "pty_slave"; |
782 | pts_driver->name = "pts"; |
783 | pts_driver->major = UNIX98_PTY_SLAVE_MAJOR; |
784 | pts_driver->minor_start = 0; |
785 | pts_driver->type = TTY_DRIVER_TYPE_PTY; |
786 | pts_driver->subtype = PTY_TYPE_SLAVE; |
787 | pts_driver->init_termios = tty_std_termios; |
788 | pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
789 | pts_driver->init_termios.c_ispeed = 38400; |
790 | pts_driver->init_termios.c_ospeed = 38400; |
791 | pts_driver->other = ptm_driver; |
792 | tty_set_operations(pts_driver, &pty_unix98_ops); |
793 | |
794 | if (tty_register_driver(ptm_driver)) |
795 | panic("Couldn't register Unix98 ptm driver"); |
796 | if (tty_register_driver(pts_driver)) |
797 | panic("Couldn't register Unix98 pts driver"); |
798 | |
799 | /* Now create the /dev/ptmx special device */ |
800 | tty_default_fops(&ptmx_fops); |
801 | ptmx_fops.open = ptmx_open; |
802 | |
803 | cdev_init(&ptmx_cdev, &ptmx_fops); |
804 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || |
805 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) |
806 | panic("Couldn't register /dev/ptmx driver"); |
807 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); |
808 | } |
809 | |
810 | #else |
811 | static inline void unix98_pty_init(void) { } |
812 | #endif |
813 | |
814 | static int __init pty_init(void) |
815 | { |
816 | legacy_pty_init(); |
817 | unix98_pty_init(); |
818 | return 0; |
819 | } |
820 | module_init(pty_init); |
821 |
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