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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 | #include <linux/errno.h> | |
11 | #include <linux/interrupt.h> | |
12 | #include <linux/tty.h> | |
13 | #include <linux/tty_flip.h> | |
14 | #include <linux/fcntl.h> | |
15 | #include <linux/sched/signal.h> | |
16 | #include <linux/string.h> | |
17 | #include <linux/major.h> | |
18 | #include <linux/mm.h> | |
19 | #include <linux/init.h> | |
20 | #include <linux/device.h> | |
21 | #include <linux/uaccess.h> | |
22 | #include <linux/bitops.h> | |
23 | #include <linux/devpts_fs.h> | |
24 | #include <linux/slab.h> | |
25 | #include <linux/mutex.h> | |
26 | #include <linux/poll.h> | |
27 | #include <linux/mount.h> | |
28 | #include <linux/file.h> | |
29 | #include <linux/ioctl.h> | |
30 | ||
31 | #undef TTY_DEBUG_HANGUP | |
32 | #ifdef TTY_DEBUG_HANGUP | |
33 | # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args) | |
34 | #else | |
35 | # define tty_debug_hangup(tty, f, args...) do {} while (0) | |
36 | #endif | |
37 | ||
38 | #ifdef CONFIG_UNIX98_PTYS | |
39 | static struct tty_driver *ptm_driver; | |
40 | static struct tty_driver *pts_driver; | |
41 | static DEFINE_MUTEX(devpts_mutex); | |
42 | #endif | |
43 | ||
44 | static void pty_close(struct tty_struct *tty, struct file *filp) | |
45 | { | |
46 | BUG_ON(!tty); | |
47 | if (tty->driver->subtype == PTY_TYPE_MASTER) | |
48 | WARN_ON(tty->count > 1); | |
49 | else { | |
50 | if (tty_io_error(tty)) | |
51 | return; | |
52 | if (tty->count > 2) | |
53 | return; | |
54 | } | |
55 | set_bit(TTY_IO_ERROR, &tty->flags); | |
56 | wake_up_interruptible(&tty->read_wait); | |
57 | wake_up_interruptible(&tty->write_wait); | |
58 | spin_lock_irq(&tty->ctrl_lock); | |
59 | tty->packet = 0; | |
60 | spin_unlock_irq(&tty->ctrl_lock); | |
61 | /* Review - krefs on tty_link ?? */ | |
62 | if (!tty->link) | |
63 | return; | |
64 | set_bit(TTY_OTHER_CLOSED, &tty->link->flags); | |
65 | wake_up_interruptible(&tty->link->read_wait); | |
66 | wake_up_interruptible(&tty->link->write_wait); | |
67 | if (tty->driver->subtype == PTY_TYPE_MASTER) { | |
68 | set_bit(TTY_OTHER_CLOSED, &tty->flags); | |
69 | #ifdef CONFIG_UNIX98_PTYS | |
70 | if (tty->driver == ptm_driver) { | |
71 | mutex_lock(&devpts_mutex); | |
72 | if (tty->link->driver_data) | |
73 | devpts_pty_kill(tty->link->driver_data); | |
74 | mutex_unlock(&devpts_mutex); | |
75 | } | |
76 | #endif | |
77 | tty_vhangup(tty->link); | |
78 | } | |
79 | } | |
80 | ||
81 | /* | |
82 | * The unthrottle routine is called by the line discipline to signal | |
83 | * that it can receive more characters. For PTY's, the TTY_THROTTLED | |
84 | * flag is always set, to force the line discipline to always call the | |
85 | * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE | |
86 | * characters in the queue. This is necessary since each time this | |
87 | * happens, we need to wake up any sleeping processes that could be | |
88 | * (1) trying to send data to the pty, or (2) waiting in wait_until_sent() | |
89 | * for the pty buffer to be drained. | |
90 | */ | |
91 | static void pty_unthrottle(struct tty_struct *tty) | |
92 | { | |
93 | tty_wakeup(tty->link); | |
94 | set_bit(TTY_THROTTLED, &tty->flags); | |
95 | } | |
96 | ||
97 | /** | |
98 | * pty_write - write to a pty | |
99 | * @tty: the tty we write from | |
100 | * @buf: kernel buffer of data | |
101 | * @count: bytes to write | |
102 | * | |
103 | * Our "hardware" write method. Data is coming from the ldisc which | |
104 | * may be in a non sleeping state. We simply throw this at the other | |
105 | * end of the link as if we were an IRQ handler receiving stuff for | |
106 | * the other side of the pty/tty pair. | |
107 | */ | |
108 | ||
109 | static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c) | |
110 | { | |
111 | struct tty_struct *to = tty->link; | |
112 | ||
113 | if (tty->stopped) | |
114 | return 0; | |
115 | ||
116 | if (c > 0) { | |
117 | /* Stuff the data into the input queue of the other end */ | |
118 | c = tty_insert_flip_string(to->port, buf, c); | |
119 | /* And shovel */ | |
120 | if (c) | |
121 | tty_flip_buffer_push(to->port); | |
122 | } | |
123 | return c; | |
124 | } | |
125 | ||
126 | /** | |
127 | * pty_write_room - write space | |
128 | * @tty: tty we are writing from | |
129 | * | |
130 | * Report how many bytes the ldisc can send into the queue for | |
131 | * the other device. | |
132 | */ | |
133 | ||
134 | static int pty_write_room(struct tty_struct *tty) | |
135 | { | |
136 | if (tty->stopped) | |
137 | return 0; | |
138 | return tty_buffer_space_avail(tty->link->port); | |
139 | } | |
140 | ||
141 | /** | |
142 | * pty_chars_in_buffer - characters currently in our tx queue | |
143 | * @tty: our tty | |
144 | * | |
145 | * Report how much we have in the transmit queue. As everything is | |
146 | * instantly at the other end this is easy to implement. | |
147 | */ | |
148 | ||
149 | static int pty_chars_in_buffer(struct tty_struct *tty) | |
150 | { | |
151 | return 0; | |
152 | } | |
153 | ||
154 | /* Set the lock flag on a pty */ | |
155 | static int pty_set_lock(struct tty_struct *tty, int __user *arg) | |
156 | { | |
157 | int val; | |
158 | if (get_user(val, arg)) | |
159 | return -EFAULT; | |
160 | if (val) | |
161 | set_bit(TTY_PTY_LOCK, &tty->flags); | |
162 | else | |
163 | clear_bit(TTY_PTY_LOCK, &tty->flags); | |
164 | return 0; | |
165 | } | |
166 | ||
167 | static int pty_get_lock(struct tty_struct *tty, int __user *arg) | |
168 | { | |
169 | int locked = test_bit(TTY_PTY_LOCK, &tty->flags); | |
170 | return put_user(locked, arg); | |
171 | } | |
172 | ||
173 | /* Set the packet mode on a pty */ | |
174 | static int pty_set_pktmode(struct tty_struct *tty, int __user *arg) | |
175 | { | |
176 | int pktmode; | |
177 | ||
178 | if (get_user(pktmode, arg)) | |
179 | return -EFAULT; | |
180 | ||
181 | spin_lock_irq(&tty->ctrl_lock); | |
182 | if (pktmode) { | |
183 | if (!tty->packet) { | |
184 | tty->link->ctrl_status = 0; | |
185 | smp_mb(); | |
186 | tty->packet = 1; | |
187 | } | |
188 | } else | |
189 | tty->packet = 0; | |
190 | spin_unlock_irq(&tty->ctrl_lock); | |
191 | ||
192 | return 0; | |
193 | } | |
194 | ||
195 | /* Get the packet mode of a pty */ | |
196 | static int pty_get_pktmode(struct tty_struct *tty, int __user *arg) | |
197 | { | |
198 | int pktmode = tty->packet; | |
199 | return put_user(pktmode, arg); | |
200 | } | |
201 | ||
202 | /* Send a signal to the slave */ | |
203 | static int pty_signal(struct tty_struct *tty, int sig) | |
204 | { | |
205 | struct pid *pgrp; | |
206 | ||
207 | if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP) | |
208 | return -EINVAL; | |
209 | ||
210 | if (tty->link) { | |
211 | pgrp = tty_get_pgrp(tty->link); | |
212 | if (pgrp) | |
213 | kill_pgrp(pgrp, sig, 1); | |
214 | put_pid(pgrp); | |
215 | } | |
216 | return 0; | |
217 | } | |
218 | ||
219 | static void pty_flush_buffer(struct tty_struct *tty) | |
220 | { | |
221 | struct tty_struct *to = tty->link; | |
222 | ||
223 | if (!to) | |
224 | return; | |
225 | ||
226 | tty_buffer_flush(to, NULL); | |
227 | if (to->packet) { | |
228 | spin_lock_irq(&tty->ctrl_lock); | |
229 | tty->ctrl_status |= TIOCPKT_FLUSHWRITE; | |
230 | wake_up_interruptible(&to->read_wait); | |
231 | spin_unlock_irq(&tty->ctrl_lock); | |
232 | } | |
233 | } | |
234 | ||
235 | static int pty_open(struct tty_struct *tty, struct file *filp) | |
236 | { | |
237 | if (!tty || !tty->link) | |
238 | return -ENODEV; | |
239 | ||
240 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) | |
241 | goto out; | |
242 | if (test_bit(TTY_PTY_LOCK, &tty->link->flags)) | |
243 | goto out; | |
244 | if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1) | |
245 | goto out; | |
246 | ||
247 | clear_bit(TTY_IO_ERROR, &tty->flags); | |
248 | clear_bit(TTY_OTHER_CLOSED, &tty->link->flags); | |
249 | set_bit(TTY_THROTTLED, &tty->flags); | |
250 | return 0; | |
251 | ||
252 | out: | |
253 | set_bit(TTY_IO_ERROR, &tty->flags); | |
254 | return -EIO; | |
255 | } | |
256 | ||
257 | static void pty_set_termios(struct tty_struct *tty, | |
258 | struct ktermios *old_termios) | |
259 | { | |
260 | /* See if packet mode change of state. */ | |
261 | if (tty->link && tty->link->packet) { | |
262 | int extproc = (old_termios->c_lflag & EXTPROC) | L_EXTPROC(tty); | |
263 | int old_flow = ((old_termios->c_iflag & IXON) && | |
264 | (old_termios->c_cc[VSTOP] == '\023') && | |
265 | (old_termios->c_cc[VSTART] == '\021')); | |
266 | int new_flow = (I_IXON(tty) && | |
267 | STOP_CHAR(tty) == '\023' && | |
268 | START_CHAR(tty) == '\021'); | |
269 | if ((old_flow != new_flow) || extproc) { | |
270 | spin_lock_irq(&tty->ctrl_lock); | |
271 | if (old_flow != new_flow) { | |
272 | tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP); | |
273 | if (new_flow) | |
274 | tty->ctrl_status |= TIOCPKT_DOSTOP; | |
275 | else | |
276 | tty->ctrl_status |= TIOCPKT_NOSTOP; | |
277 | } | |
278 | if (extproc) | |
279 | tty->ctrl_status |= TIOCPKT_IOCTL; | |
280 | spin_unlock_irq(&tty->ctrl_lock); | |
281 | wake_up_interruptible(&tty->link->read_wait); | |
282 | } | |
283 | } | |
284 | ||
285 | tty->termios.c_cflag &= ~(CSIZE | PARENB); | |
286 | tty->termios.c_cflag |= (CS8 | CREAD); | |
287 | } | |
288 | ||
289 | /** | |
290 | * pty_do_resize - resize event | |
291 | * @tty: tty being resized | |
292 | * @ws: window size being set. | |
293 | * | |
294 | * Update the termios variables and send the necessary signals to | |
295 | * peform a terminal resize correctly | |
296 | */ | |
297 | ||
298 | static int pty_resize(struct tty_struct *tty, struct winsize *ws) | |
299 | { | |
300 | struct pid *pgrp, *rpgrp; | |
301 | struct tty_struct *pty = tty->link; | |
302 | ||
303 | /* For a PTY we need to lock the tty side */ | |
304 | mutex_lock(&tty->winsize_mutex); | |
305 | if (!memcmp(ws, &tty->winsize, sizeof(*ws))) | |
306 | goto done; | |
307 | ||
308 | /* Signal the foreground process group of both ptys */ | |
309 | pgrp = tty_get_pgrp(tty); | |
310 | rpgrp = tty_get_pgrp(pty); | |
311 | ||
312 | if (pgrp) | |
313 | kill_pgrp(pgrp, SIGWINCH, 1); | |
314 | if (rpgrp != pgrp && rpgrp) | |
315 | kill_pgrp(rpgrp, SIGWINCH, 1); | |
316 | ||
317 | put_pid(pgrp); | |
318 | put_pid(rpgrp); | |
319 | ||
320 | tty->winsize = *ws; | |
321 | pty->winsize = *ws; /* Never used so will go away soon */ | |
322 | done: | |
323 | mutex_unlock(&tty->winsize_mutex); | |
324 | return 0; | |
325 | } | |
326 | ||
327 | /** | |
328 | * pty_start - start() handler | |
329 | * pty_stop - stop() handler | |
330 | * @tty: tty being flow-controlled | |
331 | * | |
332 | * Propagates the TIOCPKT status to the master pty. | |
333 | * | |
334 | * NB: only the master pty can be in packet mode so only the slave | |
335 | * needs start()/stop() handlers | |
336 | */ | |
337 | static void pty_start(struct tty_struct *tty) | |
338 | { | |
339 | unsigned long flags; | |
340 | ||
341 | if (tty->link && tty->link->packet) { | |
342 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
343 | tty->ctrl_status &= ~TIOCPKT_STOP; | |
344 | tty->ctrl_status |= TIOCPKT_START; | |
345 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
346 | wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); | |
347 | } | |
348 | } | |
349 | ||
350 | static void pty_stop(struct tty_struct *tty) | |
351 | { | |
352 | unsigned long flags; | |
353 | ||
354 | if (tty->link && tty->link->packet) { | |
355 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
356 | tty->ctrl_status &= ~TIOCPKT_START; | |
357 | tty->ctrl_status |= TIOCPKT_STOP; | |
358 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
359 | wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); | |
360 | } | |
361 | } | |
362 | ||
363 | /** | |
364 | * pty_common_install - set up the pty pair | |
365 | * @driver: the pty driver | |
366 | * @tty: the tty being instantiated | |
367 | * @legacy: true if this is BSD style | |
368 | * | |
369 | * Perform the initial set up for the tty/pty pair. Called from the | |
370 | * tty layer when the port is first opened. | |
371 | * | |
372 | * Locking: the caller must hold the tty_mutex | |
373 | */ | |
374 | static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, | |
375 | bool legacy) | |
376 | { | |
377 | struct tty_struct *o_tty; | |
378 | struct tty_port *ports[2]; | |
379 | int idx = tty->index; | |
380 | int retval = -ENOMEM; | |
381 | ||
382 | /* Opening the slave first has always returned -EIO */ | |
383 | if (driver->subtype != PTY_TYPE_MASTER) | |
384 | return -EIO; | |
385 | ||
386 | ports[0] = kmalloc(sizeof **ports, GFP_KERNEL); | |
387 | ports[1] = kmalloc(sizeof **ports, GFP_KERNEL); | |
388 | if (!ports[0] || !ports[1]) | |
389 | goto err; | |
390 | if (!try_module_get(driver->other->owner)) { | |
391 | /* This cannot in fact currently happen */ | |
392 | goto err; | |
393 | } | |
394 | o_tty = alloc_tty_struct(driver->other, idx); | |
395 | if (!o_tty) | |
396 | goto err_put_module; | |
397 | ||
398 | tty_set_lock_subclass(o_tty); | |
399 | lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE); | |
400 | ||
401 | if (legacy) { | |
402 | /* We always use new tty termios data so we can do this | |
403 | the easy way .. */ | |
404 | tty_init_termios(tty); | |
405 | tty_init_termios(o_tty); | |
406 | ||
407 | driver->other->ttys[idx] = o_tty; | |
408 | driver->ttys[idx] = tty; | |
409 | } else { | |
410 | memset(&tty->termios_locked, 0, sizeof(tty->termios_locked)); | |
411 | tty->termios = driver->init_termios; | |
412 | memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked)); | |
413 | o_tty->termios = driver->other->init_termios; | |
414 | } | |
415 | ||
416 | /* | |
417 | * Everything allocated ... set up the o_tty structure. | |
418 | */ | |
419 | tty_driver_kref_get(driver->other); | |
420 | /* Establish the links in both directions */ | |
421 | tty->link = o_tty; | |
422 | o_tty->link = tty; | |
423 | tty_port_init(ports[0]); | |
424 | tty_port_init(ports[1]); | |
425 | tty_buffer_set_limit(ports[0], 8192); | |
426 | tty_buffer_set_limit(ports[1], 8192); | |
427 | o_tty->port = ports[0]; | |
428 | tty->port = ports[1]; | |
429 | o_tty->port->itty = o_tty; | |
430 | ||
431 | tty_buffer_set_lock_subclass(o_tty->port); | |
432 | ||
433 | tty_driver_kref_get(driver); | |
434 | tty->count++; | |
435 | o_tty->count++; | |
436 | return 0; | |
437 | ||
438 | err_put_module: | |
439 | module_put(driver->other->owner); | |
440 | err: | |
441 | kfree(ports[0]); | |
442 | kfree(ports[1]); | |
443 | return retval; | |
444 | } | |
445 | ||
446 | static void pty_cleanup(struct tty_struct *tty) | |
447 | { | |
448 | tty_port_put(tty->port); | |
449 | } | |
450 | ||
451 | /* Traditional BSD devices */ | |
452 | #ifdef CONFIG_LEGACY_PTYS | |
453 | ||
454 | static int pty_install(struct tty_driver *driver, struct tty_struct *tty) | |
455 | { | |
456 | return pty_common_install(driver, tty, true); | |
457 | } | |
458 | ||
459 | static void pty_remove(struct tty_driver *driver, struct tty_struct *tty) | |
460 | { | |
461 | struct tty_struct *pair = tty->link; | |
462 | driver->ttys[tty->index] = NULL; | |
463 | if (pair) | |
464 | pair->driver->ttys[pair->index] = NULL; | |
465 | } | |
466 | ||
467 | static int pty_bsd_ioctl(struct tty_struct *tty, | |
468 | unsigned int cmd, unsigned long arg) | |
469 | { | |
470 | switch (cmd) { | |
471 | case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ | |
472 | return pty_set_lock(tty, (int __user *) arg); | |
473 | case TIOCGPTLCK: /* Get PT Lock status */ | |
474 | return pty_get_lock(tty, (int __user *)arg); | |
475 | case TIOCPKT: /* Set PT packet mode */ | |
476 | return pty_set_pktmode(tty, (int __user *)arg); | |
477 | case TIOCGPKT: /* Get PT packet mode */ | |
478 | return pty_get_pktmode(tty, (int __user *)arg); | |
479 | case TIOCSIG: /* Send signal to other side of pty */ | |
480 | return pty_signal(tty, (int) arg); | |
481 | case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */ | |
482 | return -EINVAL; | |
483 | } | |
484 | return -ENOIOCTLCMD; | |
485 | } | |
486 | ||
487 | static long pty_bsd_compat_ioctl(struct tty_struct *tty, | |
488 | unsigned int cmd, unsigned long arg) | |
489 | { | |
490 | /* | |
491 | * PTY ioctls don't require any special translation between 32-bit and | |
492 | * 64-bit userspace, they are already compatible. | |
493 | */ | |
494 | return pty_bsd_ioctl(tty, cmd, arg); | |
495 | } | |
496 | ||
497 | static int legacy_count = CONFIG_LEGACY_PTY_COUNT; | |
498 | /* | |
499 | * not really modular, but the easiest way to keep compat with existing | |
500 | * bootargs behaviour is to continue using module_param here. | |
501 | */ | |
502 | module_param(legacy_count, int, 0); | |
503 | ||
504 | /* | |
505 | * The master side of a pty can do TIOCSPTLCK and thus | |
506 | * has pty_bsd_ioctl. | |
507 | */ | |
508 | static const struct tty_operations master_pty_ops_bsd = { | |
509 | .install = pty_install, | |
510 | .open = pty_open, | |
511 | .close = pty_close, | |
512 | .write = pty_write, | |
513 | .write_room = pty_write_room, | |
514 | .flush_buffer = pty_flush_buffer, | |
515 | .chars_in_buffer = pty_chars_in_buffer, | |
516 | .unthrottle = pty_unthrottle, | |
517 | .ioctl = pty_bsd_ioctl, | |
518 | .compat_ioctl = pty_bsd_compat_ioctl, | |
519 | .cleanup = pty_cleanup, | |
520 | .resize = pty_resize, | |
521 | .remove = pty_remove | |
522 | }; | |
523 | ||
524 | static const struct tty_operations slave_pty_ops_bsd = { | |
525 | .install = pty_install, | |
526 | .open = pty_open, | |
527 | .close = pty_close, | |
528 | .write = pty_write, | |
529 | .write_room = pty_write_room, | |
530 | .flush_buffer = pty_flush_buffer, | |
531 | .chars_in_buffer = pty_chars_in_buffer, | |
532 | .unthrottle = pty_unthrottle, | |
533 | .set_termios = pty_set_termios, | |
534 | .cleanup = pty_cleanup, | |
535 | .resize = pty_resize, | |
536 | .start = pty_start, | |
537 | .stop = pty_stop, | |
538 | .remove = pty_remove | |
539 | }; | |
540 | ||
541 | static void __init legacy_pty_init(void) | |
542 | { | |
543 | struct tty_driver *pty_driver, *pty_slave_driver; | |
544 | ||
545 | if (legacy_count <= 0) | |
546 | return; | |
547 | ||
548 | pty_driver = tty_alloc_driver(legacy_count, | |
549 | TTY_DRIVER_RESET_TERMIOS | | |
550 | TTY_DRIVER_REAL_RAW | | |
551 | TTY_DRIVER_DYNAMIC_ALLOC); | |
552 | if (IS_ERR(pty_driver)) | |
553 | panic("Couldn't allocate pty driver"); | |
554 | ||
555 | pty_slave_driver = tty_alloc_driver(legacy_count, | |
556 | TTY_DRIVER_RESET_TERMIOS | | |
557 | TTY_DRIVER_REAL_RAW | | |
558 | TTY_DRIVER_DYNAMIC_ALLOC); | |
559 | if (IS_ERR(pty_slave_driver)) | |
560 | panic("Couldn't allocate pty slave driver"); | |
561 | ||
562 | pty_driver->driver_name = "pty_master"; | |
563 | pty_driver->name = "pty"; | |
564 | pty_driver->major = PTY_MASTER_MAJOR; | |
565 | pty_driver->minor_start = 0; | |
566 | pty_driver->type = TTY_DRIVER_TYPE_PTY; | |
567 | pty_driver->subtype = PTY_TYPE_MASTER; | |
568 | pty_driver->init_termios = tty_std_termios; | |
569 | pty_driver->init_termios.c_iflag = 0; | |
570 | pty_driver->init_termios.c_oflag = 0; | |
571 | pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; | |
572 | pty_driver->init_termios.c_lflag = 0; | |
573 | pty_driver->init_termios.c_ispeed = 38400; | |
574 | pty_driver->init_termios.c_ospeed = 38400; | |
575 | pty_driver->other = pty_slave_driver; | |
576 | tty_set_operations(pty_driver, &master_pty_ops_bsd); | |
577 | ||
578 | pty_slave_driver->driver_name = "pty_slave"; | |
579 | pty_slave_driver->name = "ttyp"; | |
580 | pty_slave_driver->major = PTY_SLAVE_MAJOR; | |
581 | pty_slave_driver->minor_start = 0; | |
582 | pty_slave_driver->type = TTY_DRIVER_TYPE_PTY; | |
583 | pty_slave_driver->subtype = PTY_TYPE_SLAVE; | |
584 | pty_slave_driver->init_termios = tty_std_termios; | |
585 | pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; | |
586 | pty_slave_driver->init_termios.c_ispeed = 38400; | |
587 | pty_slave_driver->init_termios.c_ospeed = 38400; | |
588 | pty_slave_driver->other = pty_driver; | |
589 | tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd); | |
590 | ||
591 | if (tty_register_driver(pty_driver)) | |
592 | panic("Couldn't register pty driver"); | |
593 | if (tty_register_driver(pty_slave_driver)) | |
594 | panic("Couldn't register pty slave driver"); | |
595 | } | |
596 | #else | |
597 | static inline void legacy_pty_init(void) { } | |
598 | #endif | |
599 | ||
600 | /* Unix98 devices */ | |
601 | #ifdef CONFIG_UNIX98_PTYS | |
602 | static struct cdev ptmx_cdev; | |
603 | ||
604 | /** | |
605 | * ptm_open_peer - open the peer of a pty | |
606 | * @master: the open struct file of the ptmx device node | |
607 | * @tty: the master of the pty being opened | |
608 | * @flags: the flags for open | |
609 | * | |
610 | * Provide a race free way for userspace to open the slave end of a pty | |
611 | * (where they have the master fd and cannot access or trust the mount | |
612 | * namespace /dev/pts was mounted inside). | |
613 | */ | |
614 | int ptm_open_peer(struct file *master, struct tty_struct *tty, int flags) | |
615 | { | |
616 | int fd = -1; | |
617 | struct file *filp; | |
618 | int retval = -EINVAL; | |
619 | struct path path; | |
620 | ||
621 | if (tty->driver != ptm_driver) | |
622 | return -EIO; | |
623 | ||
624 | fd = get_unused_fd_flags(0); | |
625 | if (fd < 0) { | |
626 | retval = fd; | |
627 | goto err; | |
628 | } | |
629 | ||
630 | /* Compute the slave's path */ | |
631 | path.mnt = devpts_mntget(master, tty->driver_data); | |
632 | if (IS_ERR(path.mnt)) { | |
633 | retval = PTR_ERR(path.mnt); | |
634 | goto err_put; | |
635 | } | |
636 | path.dentry = tty->link->driver_data; | |
637 | ||
638 | filp = dentry_open(&path, flags, current_cred()); | |
639 | mntput(path.mnt); | |
640 | if (IS_ERR(filp)) { | |
641 | retval = PTR_ERR(filp); | |
642 | goto err_put; | |
643 | } | |
644 | ||
645 | fd_install(fd, filp); | |
646 | return fd; | |
647 | ||
648 | err_put: | |
649 | put_unused_fd(fd); | |
650 | err: | |
651 | return retval; | |
652 | } | |
653 | ||
654 | static int pty_unix98_ioctl(struct tty_struct *tty, | |
655 | unsigned int cmd, unsigned long arg) | |
656 | { | |
657 | switch (cmd) { | |
658 | case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ | |
659 | return pty_set_lock(tty, (int __user *)arg); | |
660 | case TIOCGPTLCK: /* Get PT Lock status */ | |
661 | return pty_get_lock(tty, (int __user *)arg); | |
662 | case TIOCPKT: /* Set PT packet mode */ | |
663 | return pty_set_pktmode(tty, (int __user *)arg); | |
664 | case TIOCGPKT: /* Get PT packet mode */ | |
665 | return pty_get_pktmode(tty, (int __user *)arg); | |
666 | case TIOCGPTN: /* Get PT Number */ | |
667 | return put_user(tty->index, (unsigned int __user *)arg); | |
668 | case TIOCSIG: /* Send signal to other side of pty */ | |
669 | return pty_signal(tty, (int) arg); | |
670 | } | |
671 | ||
672 | return -ENOIOCTLCMD; | |
673 | } | |
674 | ||
675 | static long pty_unix98_compat_ioctl(struct tty_struct *tty, | |
676 | unsigned int cmd, unsigned long arg) | |
677 | { | |
678 | /* | |
679 | * PTY ioctls don't require any special translation between 32-bit and | |
680 | * 64-bit userspace, they are already compatible. | |
681 | */ | |
682 | return pty_unix98_ioctl(tty, cmd, arg); | |
683 | } | |
684 | ||
685 | /** | |
686 | * ptm_unix98_lookup - find a pty master | |
687 | * @driver: ptm driver | |
688 | * @idx: tty index | |
689 | * | |
690 | * Look up a pty master device. Called under the tty_mutex for now. | |
691 | * This provides our locking. | |
692 | */ | |
693 | ||
694 | static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, | |
695 | struct file *file, int idx) | |
696 | { | |
697 | /* Master must be open via /dev/ptmx */ | |
698 | return ERR_PTR(-EIO); | |
699 | } | |
700 | ||
701 | /** | |
702 | * pts_unix98_lookup - find a pty slave | |
703 | * @driver: pts driver | |
704 | * @idx: tty index | |
705 | * | |
706 | * Look up a pty master device. Called under the tty_mutex for now. | |
707 | * This provides our locking for the tty pointer. | |
708 | */ | |
709 | ||
710 | static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, | |
711 | struct file *file, int idx) | |
712 | { | |
713 | struct tty_struct *tty; | |
714 | ||
715 | mutex_lock(&devpts_mutex); | |
716 | tty = devpts_get_priv(file->f_path.dentry); | |
717 | mutex_unlock(&devpts_mutex); | |
718 | /* Master must be open before slave */ | |
719 | if (!tty) | |
720 | return ERR_PTR(-EIO); | |
721 | return tty; | |
722 | } | |
723 | ||
724 | static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) | |
725 | { | |
726 | return pty_common_install(driver, tty, false); | |
727 | } | |
728 | ||
729 | /* this is called once with whichever end is closed last */ | |
730 | static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) | |
731 | { | |
732 | struct pts_fs_info *fsi; | |
733 | ||
734 | if (tty->driver->subtype == PTY_TYPE_MASTER) | |
735 | fsi = tty->driver_data; | |
736 | else | |
737 | fsi = tty->link->driver_data; | |
738 | ||
739 | if (fsi) { | |
740 | devpts_kill_index(fsi, tty->index); | |
741 | devpts_release(fsi); | |
742 | } | |
743 | } | |
744 | ||
745 | static const struct tty_operations ptm_unix98_ops = { | |
746 | .lookup = ptm_unix98_lookup, | |
747 | .install = pty_unix98_install, | |
748 | .remove = pty_unix98_remove, | |
749 | .open = pty_open, | |
750 | .close = pty_close, | |
751 | .write = pty_write, | |
752 | .write_room = pty_write_room, | |
753 | .flush_buffer = pty_flush_buffer, | |
754 | .chars_in_buffer = pty_chars_in_buffer, | |
755 | .unthrottle = pty_unthrottle, | |
756 | .ioctl = pty_unix98_ioctl, | |
757 | .compat_ioctl = pty_unix98_compat_ioctl, | |
758 | .resize = pty_resize, | |
759 | .cleanup = pty_cleanup | |
760 | }; | |
761 | ||
762 | static const struct tty_operations pty_unix98_ops = { | |
763 | .lookup = pts_unix98_lookup, | |
764 | .install = pty_unix98_install, | |
765 | .remove = pty_unix98_remove, | |
766 | .open = pty_open, | |
767 | .close = pty_close, | |
768 | .write = pty_write, | |
769 | .write_room = pty_write_room, | |
770 | .flush_buffer = pty_flush_buffer, | |
771 | .chars_in_buffer = pty_chars_in_buffer, | |
772 | .unthrottle = pty_unthrottle, | |
773 | .set_termios = pty_set_termios, | |
774 | .start = pty_start, | |
775 | .stop = pty_stop, | |
776 | .cleanup = pty_cleanup, | |
777 | }; | |
778 | ||
779 | /** | |
780 | * ptmx_open - open a unix 98 pty master | |
781 | * @inode: inode of device file | |
782 | * @filp: file pointer to tty | |
783 | * | |
784 | * Allocate a unix98 pty master device from the ptmx driver. | |
785 | * | |
786 | * Locking: tty_mutex protects the init_dev work. tty->count should | |
787 | * protect the rest. | |
788 | * allocated_ptys_lock handles the list of free pty numbers | |
789 | */ | |
790 | ||
791 | static int ptmx_open(struct inode *inode, struct file *filp) | |
792 | { | |
793 | struct pts_fs_info *fsi; | |
794 | struct tty_struct *tty; | |
795 | struct dentry *dentry; | |
796 | int retval; | |
797 | int index; | |
798 | ||
799 | nonseekable_open(inode, filp); | |
800 | ||
801 | /* We refuse fsnotify events on ptmx, since it's a shared resource */ | |
802 | filp->f_mode |= FMODE_NONOTIFY; | |
803 | ||
804 | retval = tty_alloc_file(filp); | |
805 | if (retval) | |
806 | return retval; | |
807 | ||
808 | fsi = devpts_acquire(filp); | |
809 | if (IS_ERR(fsi)) { | |
810 | retval = PTR_ERR(fsi); | |
811 | goto out_free_file; | |
812 | } | |
813 | ||
814 | /* find a device that is not in use. */ | |
815 | mutex_lock(&devpts_mutex); | |
816 | index = devpts_new_index(fsi); | |
817 | mutex_unlock(&devpts_mutex); | |
818 | ||
819 | retval = index; | |
820 | if (index < 0) | |
821 | goto out_put_fsi; | |
822 | ||
823 | ||
824 | mutex_lock(&tty_mutex); | |
825 | tty = tty_init_dev(ptm_driver, index); | |
826 | /* The tty returned here is locked so we can safely | |
827 | drop the mutex */ | |
828 | mutex_unlock(&tty_mutex); | |
829 | ||
830 | retval = PTR_ERR(tty); | |
831 | if (IS_ERR(tty)) | |
832 | goto out; | |
833 | ||
834 | /* | |
835 | * From here on out, the tty is "live", and the index and | |
836 | * fsi will be killed/put by the tty_release() | |
837 | */ | |
838 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ | |
839 | tty->driver_data = fsi; | |
840 | ||
841 | tty_add_file(tty, filp); | |
842 | ||
843 | dentry = devpts_pty_new(fsi, index, tty->link); | |
844 | if (IS_ERR(dentry)) { | |
845 | retval = PTR_ERR(dentry); | |
846 | goto err_release; | |
847 | } | |
848 | tty->link->driver_data = dentry; | |
849 | ||
850 | retval = ptm_driver->ops->open(tty, filp); | |
851 | if (retval) | |
852 | goto err_release; | |
853 | ||
854 | tty_debug_hangup(tty, "opening (count=%d)\n", tty->count); | |
855 | ||
856 | tty_unlock(tty); | |
857 | return 0; | |
858 | err_release: | |
859 | tty_unlock(tty); | |
860 | // This will also put-ref the fsi | |
861 | tty_release(inode, filp); | |
862 | return retval; | |
863 | out: | |
864 | devpts_kill_index(fsi, index); | |
865 | out_put_fsi: | |
866 | devpts_release(fsi); | |
867 | out_free_file: | |
868 | tty_free_file(filp); | |
869 | return retval; | |
870 | } | |
871 | ||
872 | static struct file_operations ptmx_fops __ro_after_init; | |
873 | ||
874 | static void __init unix98_pty_init(void) | |
875 | { | |
876 | ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, | |
877 | TTY_DRIVER_RESET_TERMIOS | | |
878 | TTY_DRIVER_REAL_RAW | | |
879 | TTY_DRIVER_DYNAMIC_DEV | | |
880 | TTY_DRIVER_DEVPTS_MEM | | |
881 | TTY_DRIVER_DYNAMIC_ALLOC); | |
882 | if (IS_ERR(ptm_driver)) | |
883 | panic("Couldn't allocate Unix98 ptm driver"); | |
884 | pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, | |
885 | TTY_DRIVER_RESET_TERMIOS | | |
886 | TTY_DRIVER_REAL_RAW | | |
887 | TTY_DRIVER_DYNAMIC_DEV | | |
888 | TTY_DRIVER_DEVPTS_MEM | | |
889 | TTY_DRIVER_DYNAMIC_ALLOC); | |
890 | if (IS_ERR(pts_driver)) | |
891 | panic("Couldn't allocate Unix98 pts driver"); | |
892 | ||
893 | ptm_driver->driver_name = "pty_master"; | |
894 | ptm_driver->name = "ptm"; | |
895 | ptm_driver->major = UNIX98_PTY_MASTER_MAJOR; | |
896 | ptm_driver->minor_start = 0; | |
897 | ptm_driver->type = TTY_DRIVER_TYPE_PTY; | |
898 | ptm_driver->subtype = PTY_TYPE_MASTER; | |
899 | ptm_driver->init_termios = tty_std_termios; | |
900 | ptm_driver->init_termios.c_iflag = 0; | |
901 | ptm_driver->init_termios.c_oflag = 0; | |
902 | ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; | |
903 | ptm_driver->init_termios.c_lflag = 0; | |
904 | ptm_driver->init_termios.c_ispeed = 38400; | |
905 | ptm_driver->init_termios.c_ospeed = 38400; | |
906 | ptm_driver->other = pts_driver; | |
907 | tty_set_operations(ptm_driver, &ptm_unix98_ops); | |
908 | ||
909 | pts_driver->driver_name = "pty_slave"; | |
910 | pts_driver->name = "pts"; | |
911 | pts_driver->major = UNIX98_PTY_SLAVE_MAJOR; | |
912 | pts_driver->minor_start = 0; | |
913 | pts_driver->type = TTY_DRIVER_TYPE_PTY; | |
914 | pts_driver->subtype = PTY_TYPE_SLAVE; | |
915 | pts_driver->init_termios = tty_std_termios; | |
916 | pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; | |
917 | pts_driver->init_termios.c_ispeed = 38400; | |
918 | pts_driver->init_termios.c_ospeed = 38400; | |
919 | pts_driver->other = ptm_driver; | |
920 | tty_set_operations(pts_driver, &pty_unix98_ops); | |
921 | ||
922 | if (tty_register_driver(ptm_driver)) | |
923 | panic("Couldn't register Unix98 ptm driver"); | |
924 | if (tty_register_driver(pts_driver)) | |
925 | panic("Couldn't register Unix98 pts driver"); | |
926 | ||
927 | /* Now create the /dev/ptmx special device */ | |
928 | tty_default_fops(&ptmx_fops); | |
929 | ptmx_fops.open = ptmx_open; | |
930 | ||
931 | cdev_init(&ptmx_cdev, &ptmx_fops); | |
932 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || | |
933 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) | |
934 | panic("Couldn't register /dev/ptmx driver"); | |
935 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); | |
936 | } | |
937 | ||
938 | #else | |
939 | static inline void unix98_pty_init(void) { } | |
940 | #endif | |
941 | ||
942 | static int __init pty_init(void) | |
943 | { | |
944 | legacy_pty_init(); | |
945 | unix98_pty_init(); | |
946 | return 0; | |
947 | } | |
948 | device_initcall(pty_init); |