1 /*
2 * Copyright (c) 1997-2019 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28 /*
29 * Copyright (c) 1982, 1986, 1989, 1993
30 * The Regents of the University of California. All rights reserved.
31 *
32 * Redistribution and use in source and binary forms, with or without
33 * modification, are permitted provided that the following conditions
34 * are met:
35 * 1. Redistributions of source code must retain the above copyright
36 * notice, this list of conditions and the following disclaimer.
37 * 2. Redistributions in binary form must reproduce the above copyright
38 * notice, this list of conditions and the following disclaimer in the
39 * documentation and/or other materials provided with the distribution.
40 * 3. All advertising materials mentioning features or use of this software
41 * must display the following acknowledgement:
42 * This product includes software developed by the University of
43 * California, Berkeley and its contributors.
44 * 4. Neither the name of the University nor the names of its contributors
45 * may be used to endorse or promote products derived from this software
46 * without specific prior written permission.
47 *
48 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58 * SUCH DAMAGE.
59 *
60 * @(#)tty_pty.c 8.4 (Berkeley) 2/20/95
61 */
62
63 /*
64 * Pseudo-teletype Driver
65 * (Actually two drivers, requiring two entries in 'cdevsw')
66 */
67 #include "pty.h" /* XXX */
68
69 #include <sys/param.h>
70 #include <sys/systm.h>
71 #include <sys/ioctl.h>
72 #include <sys/proc_internal.h>
73 #include <sys/kauth.h>
74 #include <sys/tty.h>
75 #include <sys/conf.h>
76 #include <sys/file_internal.h>
77 #include <sys/uio_internal.h>
78 #include <sys/kernel.h>
79 #include <sys/vnode.h>
80 #include <sys/user.h>
81 #include <sys/signalvar.h>
82 #include <sys/sysctl.h>
83 #include <miscfs/devfs/devfs.h>
84 #include <miscfs/devfs/devfsdefs.h> /* DEVFS_LOCK()/DEVFS_UNLOCK() */
85 #include <libkern/section_keywords.h>
86
87 #if CONFIG_MACF
88 #include <security/mac_framework.h>
89 #endif
90
91 #include "tty_dev.h"
92
93 /*
94 * Forward declarations
95 */
96 int ptmx_init(int n_ptys);
97 static struct ptmx_ioctl *ptmx_get_ioctl(int minor, int open_flag);
98 static int ptmx_free_ioctl(int minor, int open_flag);
99 static int ptmx_get_name(int minor, char *buffer, size_t size);
100 static void ptsd_revoke_knotes(int minor, struct tty *tp);
101
102 extern d_open_t ptsopen;
103 extern d_close_t ptsclose;
104 extern d_read_t ptsread;
105 extern d_write_t ptswrite;
106 extern d_ioctl_t ptyioctl;
107 extern d_stop_t ptsstop;
108 extern d_reset_t ptsreset;
109 extern d_select_t ptsselect;
110
111 extern d_open_t ptcopen;
112 extern d_close_t ptcclose;
113 extern d_read_t ptcread;
114 extern d_write_t ptcwrite;
115 extern d_stop_t ptcstop;
116 extern d_reset_t ptcreset;
117 extern d_select_t ptcselect;
118
119 static int ptmx_major; /* dynamically assigned major number */
120 static const struct cdevsw ptmx_cdev = {
121 .d_open = ptcopen,
122 .d_close = ptcclose,
123 .d_read = ptcread,
124 .d_write = ptcwrite,
125 .d_ioctl = ptyioctl,
126 .d_stop = ptcstop,
127 .d_reset = ptcreset,
128 .d_ttys = NULL,
129 .d_select = ptcselect,
130 .d_mmap = eno_mmap,
131 .d_strategy = eno_strat,
132 .d_reserved_1 = eno_getc,
133 .d_reserved_2 = eno_putc,
134 .d_type = D_TTY
135 };
136
137 static int ptsd_major; /* dynamically assigned major number */
138 static const struct cdevsw ptsd_cdev = {
139 .d_open = ptsopen,
140 .d_close = ptsclose,
141 .d_read = ptsread,
142 .d_write = ptswrite,
143 .d_ioctl = ptyioctl,
144 .d_stop = ptsstop,
145 .d_reset = ptsreset,
146 .d_ttys = NULL,
147 .d_select = ptsselect,
148 .d_mmap = eno_mmap,
149 .d_strategy = eno_strat,
150 .d_reserved_1 = eno_getc,
151 .d_reserved_2 = eno_putc,
152 .d_type = D_TTY
153 };
154
155 /*
156 * ptmx == /dev/ptmx
157 * ptsd == /dev/pts[0123456789]{3}
158 */
159 #define PTMX_TEMPLATE "ptmx"
160 #define PTSD_TEMPLATE "ttys%03d"
161
162 /*
163 * System-wide limit on the max number of cloned ptys
164 */
165 #define PTMX_MAX_DEFAULT 511 /* 512 entries */
166 #define PTMX_MAX_HARD 999 /* 1000 entries, due to PTSD_TEMPLATE */
167
168 static int ptmx_max = PTMX_MAX_DEFAULT; /* default # of clones we allow */
169
170 /* Range enforcement for the sysctl */
171 static int
sysctl_ptmx_max(__unused struct sysctl_oid * oidp,__unused void * arg1,__unused int arg2,struct sysctl_req * req)172 sysctl_ptmx_max(__unused struct sysctl_oid *oidp, __unused void *arg1,
173 __unused int arg2, struct sysctl_req *req)
174 {
175 int new_value, changed;
176 int error = sysctl_io_number(req, ptmx_max, sizeof(int), &new_value, &changed);
177 if (changed) {
178 if (new_value > 0 && new_value <= PTMX_MAX_HARD) {
179 ptmx_max = new_value;
180 } else {
181 error = EINVAL;
182 }
183 }
184 return error;
185 }
186
187 SYSCTL_NODE(_kern, KERN_TTY, tty, CTLFLAG_RW | CTLFLAG_LOCKED, 0, "TTY");
188 SYSCTL_PROC(_kern_tty, OID_AUTO, ptmx_max,
189 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
190 &ptmx_max, 0, &sysctl_ptmx_max, "I", "ptmx_max");
191
192 static int ptmx_clone(dev_t dev, int minor);
193
194 static struct tty_dev_t _ptmx_driver;
195
196 int
ptmx_init(__unused int config_count)197 ptmx_init( __unused int config_count)
198 {
199 /*
200 * We start looking at slot 10, since there are inits that will
201 * stomp explicit slots (e.g. vndevice stomps 1) below that.
202 */
203
204 /* Get a major number for /dev/ptmx */
205 if ((ptmx_major = cdevsw_add(-15, &ptmx_cdev)) == -1) {
206 printf("ptmx_init: failed to obtain /dev/ptmx major number\n");
207 return ENOENT;
208 }
209
210 if (cdevsw_setkqueueok(ptmx_major, &ptmx_cdev, CDEVSW_IS_PTC) == -1) {
211 panic("Failed to set flags on ptmx cdevsw entry.");
212 }
213
214 /* Get a major number for /dev/pts/nnn */
215 if ((ptsd_major = cdevsw_add(-15, &ptsd_cdev)) == -1) {
216 (void)cdevsw_remove(ptmx_major, &ptmx_cdev);
217 printf("ptmx_init: failed to obtain /dev/ptmx major number\n");
218 return ENOENT;
219 }
220
221 if (cdevsw_setkqueueok(ptsd_major, &ptsd_cdev, CDEVSW_IS_PTS) == -1) {
222 panic("Failed to set flags on ptmx cdevsw entry.");
223 }
224
225 /* Create the /dev/ptmx device {<major>,0} */
226 (void)devfs_make_node_clone(makedev(ptmx_major, 0),
227 DEVFS_CHAR, UID_ROOT, GID_TTY, 0666,
228 ptmx_clone, PTMX_TEMPLATE);
229
230 _ptmx_driver.primary = ptmx_major;
231 _ptmx_driver.replica = ptsd_major;
232 _ptmx_driver.fix_7828447 = 1;
233 _ptmx_driver.fix_7070978 = 1;
234 #if CONFIG_MACF
235 _ptmx_driver.mac_notify = 1;
236 #endif
237 _ptmx_driver.open = &ptmx_get_ioctl;
238 _ptmx_driver.free = &ptmx_free_ioctl;
239 _ptmx_driver.name = &ptmx_get_name;
240 _ptmx_driver.revoke = &ptsd_revoke_knotes;
241 tty_dev_register(&_ptmx_driver);
242
243 return 0;
244 }
245
246
247 static struct _ptmx_ioctl_state {
248 struct ptmx_ioctl **pis_ioctl_list; /* pointer vector */
249 int pis_total; /* total slots */
250 int pis_free; /* free slots */
251 } _state;
252 #define PTMX_GROW_VECTOR 16 /* Grow by this many slots at a time */
253
254 /*
255 * Given a minor number, return the corresponding structure for that minor
256 * number. If there isn't one, and the create flag is specified, we create
257 * one if possible.
258 *
259 * Parameters: minor Minor number of ptmx device
260 * open_flag PF_OPEN_M First open of primary
261 * PF_OPEN_S First open of replica
262 * 0 Just want ioctl struct
263 *
264 * Returns: NULL Did not exist/could not create
265 * !NULL structure corresponding minor number
266 *
267 * Locks: tty_lock() on ptmx_ioctl->pt_tty NOT held on entry or exit.
268 */
269 static struct ptmx_ioctl *
ptmx_get_ioctl(int minor,int open_flag)270 ptmx_get_ioctl(int minor, int open_flag)
271 {
272 struct ptmx_ioctl *ptmx_ioctl = NULL;
273
274 if (open_flag & PF_OPEN_M) {
275 struct ptmx_ioctl *new_ptmx_ioctl;
276
277 DEVFS_LOCK();
278 /*
279 * If we are about to allocate more memory, but we have
280 * already hit the administrative limit, then fail the
281 * operation.
282 *
283 * Note: Subtract free from total when making this
284 * check to allow unit increments, rather than
285 * snapping to the nearest PTMX_GROW_VECTOR...
286 */
287 if ((_state.pis_total - _state.pis_free) >= ptmx_max) {
288 DEVFS_UNLOCK();
289 return NULL;
290 }
291 DEVFS_UNLOCK();
292
293 new_ptmx_ioctl = kalloc_type(struct ptmx_ioctl,
294 Z_WAITOK | Z_ZERO | Z_NOFAIL);
295
296 if ((new_ptmx_ioctl->pt_tty = ttymalloc()) == NULL) {
297 kfree_type(struct ptmx_ioctl, new_ptmx_ioctl);
298 return NULL;
299 }
300
301 /*
302 * Hold the DEVFS_LOCK() over this whole operation; devfs
303 * itself does this over malloc/free as well, so this should
304 * be safe to do. We hold it longer than we want to, but
305 * doing so avoids a reallocation race on the minor number.
306 */
307 DEVFS_LOCK();
308
309 /*
310 * Check again to ensure the limit is not reached after initial check
311 * when the lock was dropped momentarily for malloc.
312 */
313 if ((_state.pis_total - _state.pis_free) >= ptmx_max) {
314 ttyfree(new_ptmx_ioctl->pt_tty);
315 DEVFS_UNLOCK();
316 kfree_type(struct ptmx_ioctl, new_ptmx_ioctl);
317 return NULL;
318 }
319
320 /* Need to allocate a larger vector? */
321 if (_state.pis_free == 0) {
322 struct ptmx_ioctl **new_pis_ioctl_list;
323 struct ptmx_ioctl **old_pis_ioctl_list = NULL;
324 size_t old_pis_total = 0;
325
326 /* Yes. */
327 new_pis_ioctl_list = kalloc_type(struct ptmx_ioctl *,
328 _state.pis_total + PTMX_GROW_VECTOR, Z_WAITOK | Z_ZERO);
329 if (new_pis_ioctl_list == NULL) {
330 ttyfree(new_ptmx_ioctl->pt_tty);
331 DEVFS_UNLOCK();
332 kfree_type(struct ptmx_ioctl, new_ptmx_ioctl);
333 return NULL;
334 }
335
336 /* If this is not the first time, copy the old over */
337 bcopy(_state.pis_ioctl_list, new_pis_ioctl_list, sizeof(struct ptmx_ioctl *) * _state.pis_total);
338 old_pis_ioctl_list = _state.pis_ioctl_list;
339 old_pis_total = _state.pis_total;
340 _state.pis_ioctl_list = new_pis_ioctl_list;
341 _state.pis_free += PTMX_GROW_VECTOR;
342 _state.pis_total += PTMX_GROW_VECTOR;
343 kfree_type(struct ptmx_ioctl *, old_pis_total, old_pis_ioctl_list);
344 }
345
346 /* is minor in range now? */
347 if (minor < 0 || minor >= _state.pis_total) {
348 ttyfree(new_ptmx_ioctl->pt_tty);
349 DEVFS_UNLOCK();
350 kfree_type(struct ptmx_ioctl, new_ptmx_ioctl);
351 return NULL;
352 }
353
354 if (_state.pis_ioctl_list[minor] != NULL) {
355 ttyfree(new_ptmx_ioctl->pt_tty);
356 DEVFS_UNLOCK();
357 kfree_type(struct ptmx_ioctl, new_ptmx_ioctl);
358
359 /* Special error value so we know to redrive the open, we've been raced */
360 return (struct ptmx_ioctl*)-1;
361 }
362
363 /* Vector is large enough; grab a new ptmx_ioctl */
364
365 /* Now grab a free slot... */
366 _state.pis_ioctl_list[minor] = new_ptmx_ioctl;
367
368 /* reduce free count */
369 _state.pis_free--;
370
371 _state.pis_ioctl_list[minor]->pt_flags |= PF_OPEN_M;
372 DEVFS_UNLOCK();
373
374 /* Create the /dev/ttysXXX device {<major>,XXX} */
375 _state.pis_ioctl_list[minor]->pt_devhandle = devfs_make_node(
376 makedev(ptsd_major, minor),
377 DEVFS_CHAR, UID_ROOT, GID_TTY, 0620,
378 PTSD_TEMPLATE, minor);
379 if (_state.pis_ioctl_list[minor]->pt_devhandle == NULL) {
380 printf("devfs_make_node() call failed for ptmx_get_ioctl()!!!!\n");
381 }
382 }
383
384 /*
385 * Lock is held here to protect race when the 'pis_ioctl_list' array is
386 * being reallocated to increase its slots.
387 */
388 DEVFS_LOCK();
389 if (minor >= 0 && minor < _state.pis_total) {
390 ptmx_ioctl = _state.pis_ioctl_list[minor];
391 if (ptmx_ioctl && (open_flag & PF_OPEN_S)) {
392 ptmx_ioctl->pt_flags |= PF_OPEN_S;
393 }
394 }
395 DEVFS_UNLOCK();
396
397 return ptmx_ioctl;
398 }
399
400 /*
401 * Locks: tty_lock() of old_ptmx_ioctl->pt_tty NOT held for this call.
402 */
403 static int
ptmx_free_ioctl(int minor,int open_flag)404 ptmx_free_ioctl(int minor, int open_flag)
405 {
406 struct ptmx_ioctl *old_ptmx_ioctl = NULL;
407
408 DEVFS_LOCK();
409
410 if (minor < 0 || minor >= _state.pis_total) {
411 DEVFS_UNLOCK();
412 return -1;
413 }
414
415 _state.pis_ioctl_list[minor]->pt_flags &= ~(open_flag);
416
417 /*
418 * Was this the last close? We will recognize it because we only get
419 * a notification on the last close of a device, and we will have
420 * cleared both the primary and the replica open bits in the flags.
421 */
422 if (!(_state.pis_ioctl_list[minor]->pt_flags & (PF_OPEN_M | PF_OPEN_S))) {
423 /* Mark as free so it can be reallocated later */
424 old_ptmx_ioctl = _state.pis_ioctl_list[minor];
425 _state.pis_ioctl_list[minor] = NULL;
426 _state.pis_free++;
427 }
428 DEVFS_UNLOCK();
429
430 /* Free old after dropping lock */
431 if (old_ptmx_ioctl != NULL) {
432 /*
433 * XXX See <rdar://5348651> and <rdar://4854638>
434 *
435 * XXX Conditional to be removed when/if tty/pty reference
436 * XXX counting and mutex implemented.
437 */
438 if (old_ptmx_ioctl->pt_devhandle != NULL) {
439 devfs_remove(old_ptmx_ioctl->pt_devhandle);
440 }
441 ttyfree(old_ptmx_ioctl->pt_tty);
442 kfree_type(struct ptmx_ioctl, old_ptmx_ioctl);
443 }
444
445 return 0; /* Success */
446 }
447
448 static int
ptmx_get_name(int minor,char * buffer,size_t size)449 ptmx_get_name(int minor, char *buffer, size_t size)
450 {
451 return snprintf(buffer, size, "/dev/" PTSD_TEMPLATE, minor);
452 }
453
454
455
456 /*
457 * Given the dev entry that's being opened, we clone the device. This driver
458 * doesn't actually use the dev entry, since we alreaqdy know who we are by
459 * being called from this code. This routine is a callback registered from
460 * devfs_make_node_clone() in ptmx_init(); it's purpose is to provide a new
461 * minor number, or to return -1, if one can't be provided.
462 *
463 * Parameters: dev The device we are cloning from
464 *
465 * Returns: >= 0 A new minor device number
466 * -1 Error: ENOMEM ("Can't alloc device")
467 *
468 * NOTE: Called with DEVFS_LOCK() held
469 */
470 static int
ptmx_clone(__unused dev_t dev,int action)471 ptmx_clone(__unused dev_t dev, int action)
472 {
473 int i;
474
475 if (action == DEVFS_CLONE_ALLOC) {
476 /* First one */
477 if (_state.pis_total == 0) {
478 return 0;
479 }
480
481 /*
482 * Note: We can add hinting on free slots, if this linear search
483 * ends up being a performance bottleneck...
484 */
485 for (i = 0; i < _state.pis_total; i++) {
486 if (_state.pis_ioctl_list[i] == NULL) {
487 break;
488 }
489 }
490
491 /*
492 * XXX We fall off the end here; if we did this twice at the
493 * XXX same time, we could return the same minor to two
494 * XXX callers; we should probably exand the pointer vector
495 * XXX here, but I need more information on the MALLOC/FREE
496 * XXX locking to ensure against a deadlock. Maybe we can
497 * XXX just high watermark it at 1/2 of PTMX_GROW_VECTOR?
498 * XXX That would require returning &minor as implict return
499 * XXX and an error code ("EAGAIN/ERESTART") or 0 as our
500 * XXX explicit return.
501 */
502
503 return i; /* empty slot or next slot */
504 }
505 return -1;
506 }
507
508
509 /*
510 * kqueue support.
511 */
512 int ptsd_kqfilter(dev_t dev, struct knote *kn);
513 static void ptsd_kqops_detach(struct knote *);
514 static int ptsd_kqops_event(struct knote *, long);
515 static int ptsd_kqops_touch(struct knote *kn, struct kevent_qos_s *kev);
516 static int ptsd_kqops_process(struct knote *kn, struct kevent_qos_s *kev);
517
518 SECURITY_READ_ONLY_EARLY(struct filterops) ptsd_kqops = {
519 .f_isfd = 1,
520 /* attach is handled by ptsd_kqfilter -- the dev node must be passed in */
521 .f_detach = ptsd_kqops_detach,
522 .f_event = ptsd_kqops_event,
523 .f_touch = ptsd_kqops_touch,
524 .f_process = ptsd_kqops_process,
525 };
526
527 /*
528 * In the normal case, by the time the driver_close() routine is called
529 * on the replica, all knotes have been detached. However in the revoke(2)
530 * case, the driver's close routine is called while there are knotes active
531 * that reference the handlers below. And we have no obvious means to
532 * reach from the driver out to the kqueue's that reference them to get
533 * them to stop.
534 */
535
536 static void
ptsd_kqops_detach(struct knote * kn)537 ptsd_kqops_detach(struct knote *kn)
538 {
539 struct tty *tp = knote_kn_hook_get_raw(kn);
540 tty_lock(tp);
541
542 if (!KNOTE_IS_AUTODETACHED(kn)) {
543 /*
544 * If we got here, it must be due to the fact that we are referencing an open
545 * tty - ttyclose always autodetaches knotes under the tty lock and marks
546 * the state as closed
547 */
548 assert(tp->t_state & TS_ISOPEN);
549
550 switch (kn->kn_filter) {
551 case EVFILT_READ:
552 KNOTE_DETACH(&tp->t_rsel.si_note, kn);
553 break;
554 case EVFILT_WRITE:
555 KNOTE_DETACH(&tp->t_wsel.si_note, kn);
556 break;
557 default:
558 panic("invalid knote %p detach, filter: %d", kn, kn->kn_filter);
559 break;
560 }
561 }
562
563 knote_kn_hook_set_raw(kn, NULL);
564
565 tty_unlock(tp);
566 ttyfree(tp);
567 }
568
569 static int
ptsd_kqops_common(struct knote * kn,struct kevent_qos_s * kev,struct tty * tp)570 ptsd_kqops_common(struct knote *kn, struct kevent_qos_s *kev, struct tty *tp)
571 {
572 int retval = 0;
573 int64_t data = 0;
574
575 TTY_LOCK_OWNED(tp);
576
577 switch (kn->kn_filter) {
578 case EVFILT_READ:
579 /*
580 * ttnread can change the tty state,
581 * hence must be done upfront, before any other check.
582 */
583 data = ttnread(tp);
584 retval = (data > 0);
585 break;
586
587 case EVFILT_WRITE:
588 if ((tp->t_outq.c_cc <= tp->t_lowat) &&
589 (tp->t_state & TS_CONNECTED)) {
590 data = tp->t_outq.c_cn - tp->t_outq.c_cc;
591 retval = 1;
592 }
593 break;
594
595 default:
596 panic("ptsd kevent: unexpected filter: %d, kn = %p, tty = %p",
597 kn->kn_filter, kn, tp);
598 break;
599 }
600
601 if (tp->t_state & TS_ZOMBIE) {
602 kn->kn_flags |= EV_EOF;
603 }
604 if (kn->kn_flags & EV_EOF) {
605 retval = 1;
606 }
607 if (retval && kev) {
608 knote_fill_kevent(kn, kev, data);
609 }
610 return retval;
611 }
612
613 static int
ptsd_kqops_event(struct knote * kn,long hint)614 ptsd_kqops_event(struct knote *kn, long hint)
615 {
616 struct tty *tp = knote_kn_hook_get_raw(kn);
617 int ret;
618
619 TTY_LOCK_OWNED(tp);
620
621 if (hint & NOTE_REVOKE) {
622 kn->kn_flags |= EV_EOF | EV_ONESHOT;
623 ret = 1;
624 } else {
625 ret = ptsd_kqops_common(kn, NULL, tp);
626 }
627
628 return ret;
629 }
630
631 static int
ptsd_kqops_touch(struct knote * kn,struct kevent_qos_s * kev)632 ptsd_kqops_touch(struct knote *kn, struct kevent_qos_s *kev)
633 {
634 struct tty *tp = knote_kn_hook_get_raw(kn);
635 int ret;
636
637 tty_lock(tp);
638
639 /* accept new kevent state */
640 kn->kn_sfflags = kev->fflags;
641 kn->kn_sdata = kev->data;
642
643 /* recapture fired state of knote */
644 ret = ptsd_kqops_common(kn, NULL, tp);
645
646 tty_unlock(tp);
647
648 return ret;
649 }
650
651 static int
ptsd_kqops_process(struct knote * kn,struct kevent_qos_s * kev)652 ptsd_kqops_process(struct knote *kn, struct kevent_qos_s *kev)
653 {
654 struct tty *tp = knote_kn_hook_get_raw(kn);
655 int ret;
656
657 tty_lock(tp);
658 ret = ptsd_kqops_common(kn, kev, tp);
659 tty_unlock(tp);
660
661 return ret;
662 }
663
664 int
ptsd_kqfilter(dev_t dev,struct knote * kn)665 ptsd_kqfilter(dev_t dev, struct knote *kn)
666 {
667 struct tty *tp = NULL;
668 struct ptmx_ioctl *pti = NULL;
669 int ret;
670
671 /* make sure we're talking about the right device type */
672 if (cdevsw[major(dev)].d_open != ptsopen) {
673 knote_set_error(kn, ENODEV);
674 return 0;
675 }
676
677 if ((pti = ptmx_get_ioctl(minor(dev), 0)) == NULL) {
678 knote_set_error(kn, ENXIO);
679 return 0;
680 }
681
682 tp = pti->pt_tty;
683 tty_lock(tp);
684
685 assert(tp->t_state & TS_ISOPEN);
686
687 kn->kn_filtid = EVFILTID_PTSD;
688 /* the tty will be freed when detaching the knote */
689 ttyhold(tp);
690 knote_kn_hook_set_raw(kn, tp);
691
692 switch (kn->kn_filter) {
693 case EVFILT_READ:
694 KNOTE_ATTACH(&tp->t_rsel.si_note, kn);
695 break;
696 case EVFILT_WRITE:
697 KNOTE_ATTACH(&tp->t_wsel.si_note, kn);
698 break;
699 default:
700 panic("ptsd kevent: unexpected filter: %d, kn = %p, tty = %p",
701 kn->kn_filter, kn, tp);
702 break;
703 }
704
705 /* capture current event state */
706 ret = ptsd_kqops_common(kn, NULL, tp);
707
708 tty_unlock(tp);
709
710 return ret;
711 }
712
713 /*
714 * Support for revoke(2).
715 */
716 static void
ptsd_revoke_knotes(__unused int minor,struct tty * tp)717 ptsd_revoke_knotes(__unused int minor, struct tty *tp)
718 {
719 tty_lock(tp);
720
721 ttwakeup(tp);
722 assert((tp->t_rsel.si_flags & SI_KNPOSTING) == 0);
723 knote(&tp->t_rsel.si_note, NOTE_REVOKE, true);
724
725 ttwwakeup(tp);
726 assert((tp->t_wsel.si_flags & SI_KNPOSTING) == 0);
727 knote(&tp->t_wsel.si_note, NOTE_REVOKE, true);
728
729 tty_unlock(tp);
730 }
731
732 /*
733 * kevent filter routines for the master side of a pty, a ptmx.
734 *
735 * Stuff the ptmx_ioctl structure into the hook for ptmx knotes. Use the
736 * embedded tty's lock for synchronization.
737 */
738
739 int ptmx_kqfilter(dev_t dev, struct knote *kn);
740 static void ptmx_kqops_detach(struct knote *);
741 static int ptmx_kqops_event(struct knote *, long);
742 static int ptmx_kqops_touch(struct knote *kn, struct kevent_qos_s *kev);
743 static int ptmx_kqops_process(struct knote *kn, struct kevent_qos_s *kev);
744 static int ptmx_kqops_common(struct knote *kn, struct kevent_qos_s *kev,
745 struct ptmx_ioctl *pti, struct tty *tp);
746
747 SECURITY_READ_ONLY_EARLY(struct filterops) ptmx_kqops = {
748 .f_isfd = 1,
749 /* attach is handled by ptmx_kqfilter -- the dev node must be passed in */
750 .f_detach = ptmx_kqops_detach,
751 .f_event = ptmx_kqops_event,
752 .f_touch = ptmx_kqops_touch,
753 .f_process = ptmx_kqops_process,
754 };
755
756 static struct ptmx_ioctl *
ptmx_knote_ioctl(struct knote * kn)757 ptmx_knote_ioctl(struct knote *kn)
758 {
759 return (struct ptmx_ioctl *)knote_kn_hook_get_raw(kn);
760 }
761
762 static struct tty *
ptmx_knote_tty(struct knote * kn)763 ptmx_knote_tty(struct knote *kn)
764 {
765 return ptmx_knote_ioctl(kn)->pt_tty;
766 }
767
768 int
ptmx_kqfilter(dev_t dev,struct knote * kn)769 ptmx_kqfilter(dev_t dev, struct knote *kn)
770 {
771 struct tty *tp = NULL;
772 struct ptmx_ioctl *pti = NULL;
773 int ret;
774
775 /* make sure we're talking about the right device type */
776 if (cdevsw[major(dev)].d_open != ptcopen) {
777 knote_set_error(kn, ENODEV);
778 return 0;
779 }
780
781 if ((pti = ptmx_get_ioctl(minor(dev), 0)) == NULL) {
782 knote_set_error(kn, ENXIO);
783 return 0;
784 }
785
786 tp = pti->pt_tty;
787 tty_lock(tp);
788
789 kn->kn_filtid = EVFILTID_PTMX;
790 /* the tty will be freed when detaching the knote */
791 ttyhold(tp);
792 knote_kn_hook_set_raw(kn, pti);
793
794 /*
795 * Attach to the ptmx's selinfo structures. This is the major difference
796 * to the ptsd filtops, which use the selinfo structures in the tty
797 * structure.
798 */
799 switch (kn->kn_filter) {
800 case EVFILT_READ:
801 KNOTE_ATTACH(&pti->pt_selr.si_note, kn);
802 break;
803 case EVFILT_WRITE:
804 KNOTE_ATTACH(&pti->pt_selw.si_note, kn);
805 break;
806 default:
807 panic("ptmx kevent: unexpected filter: %d, kn = %p, tty = %p",
808 kn->kn_filter, kn, tp);
809 break;
810 }
811
812 /* capture current event state */
813 ret = ptmx_kqops_common(kn, NULL, pti, tp);
814
815 tty_unlock(tp);
816
817 return ret;
818 }
819
820 static void
ptmx_kqops_detach(struct knote * kn)821 ptmx_kqops_detach(struct knote *kn)
822 {
823 struct ptmx_ioctl *pti = knote_kn_hook_get_raw(kn);
824 struct tty *tp = pti->pt_tty;
825
826 tty_lock(tp);
827
828 if (!KNOTE_IS_AUTODETACHED(kn)) {
829 switch (kn->kn_filter) {
830 case EVFILT_READ:
831 KNOTE_DETACH(&pti->pt_selr.si_note, kn);
832 break;
833 case EVFILT_WRITE:
834 KNOTE_DETACH(&pti->pt_selw.si_note, kn);
835 break;
836 default:
837 panic("invalid knote %p detach, filter: %d", kn, kn->kn_filter);
838 break;
839 }
840 }
841
842 knote_kn_hook_set_raw(kn, NULL);
843
844 tty_unlock(tp);
845 ttyfree(tp);
846 }
847
848 static int
ptmx_kqops_common(struct knote * kn,struct kevent_qos_s * kev,struct ptmx_ioctl * pti,struct tty * tp)849 ptmx_kqops_common(struct knote *kn, struct kevent_qos_s *kev,
850 struct ptmx_ioctl *pti, struct tty *tp)
851 {
852 int retval = 0;
853 int64_t data = 0;
854
855 TTY_LOCK_OWNED(tp);
856
857 switch (kn->kn_filter) {
858 case EVFILT_READ:
859 /* there's data on the TTY and it's not stopped */
860 if (tp->t_outq.c_cc && !(tp->t_state & TS_TTSTOP)) {
861 data = tp->t_outq.c_cc;
862 retval = data > 0;
863 } else if (((pti->pt_flags & PF_PKT) && pti->pt_send) ||
864 ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl)) {
865 retval = 1;
866 }
867 break;
868
869 case EVFILT_WRITE:
870 retval = (TTYHOG - 2) - (tp->t_rawq.c_cc + tp->t_canq.c_cc);
871 if (tp->t_canq.c_cc == 0 && (tp->t_lflag & ICANON)) {
872 retval = 1;
873 }
874 if (retval < 0) {
875 retval = 0;
876 }
877 break;
878
879 default:
880 panic("ptmx kevent: unexpected filter: %d, kn = %p, tty = %p",
881 kn->kn_filter, kn, tp);
882 break;
883 }
884
885 /* disconnects should force a wakeup (EOF) */
886 if (!(tp->t_state & TS_CONNECTED) || (tp->t_state & TS_ZOMBIE)) {
887 kn->kn_flags |= EV_EOF;
888 }
889 if (kn->kn_flags & EV_EOF) {
890 retval = 1;
891 }
892 if (retval && kev) {
893 knote_fill_kevent(kn, kev, data);
894 }
895 return retval;
896 }
897
898 static int
ptmx_kqops_event(struct knote * kn,long hint)899 ptmx_kqops_event(struct knote *kn, long hint)
900 {
901 struct ptmx_ioctl *pti = ptmx_knote_ioctl(kn);
902 struct tty *tp = ptmx_knote_tty(kn);
903 int ret;
904
905 TTY_LOCK_OWNED(tp);
906
907 if (hint & NOTE_REVOKE) {
908 kn->kn_flags |= EV_EOF | EV_ONESHOT;
909 ret = 1;
910 } else {
911 ret = ptmx_kqops_common(kn, NULL, pti, tp);
912 }
913
914 return ret;
915 }
916
917 static int
ptmx_kqops_touch(struct knote * kn,struct kevent_qos_s * kev)918 ptmx_kqops_touch(struct knote *kn, struct kevent_qos_s *kev)
919 {
920 struct ptmx_ioctl *pti = ptmx_knote_ioctl(kn);
921 struct tty *tp = ptmx_knote_tty(kn);
922 int ret;
923
924 tty_lock(tp);
925
926 /* accept new kevent state */
927 kn->kn_sfflags = kev->fflags;
928 kn->kn_sdata = kev->data;
929
930 /* recapture fired state of knote */
931 ret = ptmx_kqops_common(kn, NULL, pti, tp);
932
933 tty_unlock(tp);
934
935 return ret;
936 }
937
938 static int
ptmx_kqops_process(struct knote * kn,struct kevent_qos_s * kev)939 ptmx_kqops_process(struct knote *kn, struct kevent_qos_s *kev)
940 {
941 struct ptmx_ioctl *pti = ptmx_knote_ioctl(kn);
942 struct tty *tp = ptmx_knote_tty(kn);
943 int ret;
944
945 tty_lock(tp);
946 ret = ptmx_kqops_common(kn, kev, pti, tp);
947 tty_unlock(tp);
948
949 return ret;
950 }
951