1 /*- 2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org> 3 * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org> 4 * Copyright (c) 2009 Apple, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include "opt_ktrace.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/capability.h> 37 #include <sys/kernel.h> 38 #include <sys/lock.h> 39 #include <sys/mutex.h> 40 #include <sys/rwlock.h> 41 #include <sys/proc.h> 42 #include <sys/malloc.h> 43 #include <sys/unistd.h> 44 #include <sys/file.h> 45 #include <sys/filedesc.h> 46 #include <sys/filio.h> 47 #include <sys/fcntl.h> 48 #include <sys/kthread.h> 49 #include <sys/selinfo.h> 50 #include <sys/stdatomic.h> 51 #include <sys/queue.h> 52 #include <sys/event.h> 53 #include <sys/eventvar.h> 54 #include <sys/poll.h> 55 #include <sys/protosw.h> 56 #include <sys/resourcevar.h> 57 #include <sys/sigio.h> 58 #include <sys/signalvar.h> 59 #include <sys/socket.h> 60 #include <sys/socketvar.h> 61 #include <sys/stat.h> 62 #include <sys/sysctl.h> 63 #include <sys/sysproto.h> 64 #include <sys/syscallsubr.h> 65 #include <sys/taskqueue.h> 66 #include <sys/uio.h> 67 #ifdef KTRACE 68 #include <sys/ktrace.h> 69 #endif 70 71 #include <vm/uma.h> 72 73 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 74 75 /* 76 * This lock is used if multiple kq locks are required. This possibly 77 * should be made into a per proc lock. 78 */ 79 static struct mtx kq_global; 80 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 81 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 82 if (!haslck) \ 83 mtx_lock(lck); \ 84 haslck = 1; \ 85 } while (0) 86 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 87 if (haslck) \ 88 mtx_unlock(lck); \ 89 haslck = 0; \ 90 } while (0) 91 92 TASKQUEUE_DEFINE_THREAD(kqueue); 93 94 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 95 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 96 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 97 struct thread *td, int waitok); 98 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 99 static void kqueue_release(struct kqueue *kq, int locked); 100 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 101 uintptr_t ident, int waitok); 102 static void kqueue_task(void *arg, int pending); 103 static int kqueue_scan(struct kqueue *kq, int maxevents, 104 struct kevent_copyops *k_ops, 105 const struct timespec *timeout, 106 struct kevent *keva, struct thread *td); 107 static void kqueue_wakeup(struct kqueue *kq); 108 static struct filterops *kqueue_fo_find(int filt); 109 static void kqueue_fo_release(int filt); 110 111 static fo_rdwr_t kqueue_read; 112 static fo_rdwr_t kqueue_write; 113 static fo_truncate_t kqueue_truncate; 114 static fo_ioctl_t kqueue_ioctl; 115 static fo_poll_t kqueue_poll; 116 static fo_kqfilter_t kqueue_kqfilter; 117 static fo_stat_t kqueue_stat; 118 static fo_close_t kqueue_close; 119 120 static struct fileops kqueueops = { 121 .fo_read = kqueue_read, 122 .fo_write = kqueue_write, 123 .fo_truncate = kqueue_truncate, 124 .fo_ioctl = kqueue_ioctl, 125 .fo_poll = kqueue_poll, 126 .fo_kqfilter = kqueue_kqfilter, 127 .fo_stat = kqueue_stat, 128 .fo_close = kqueue_close, 129 .fo_chmod = invfo_chmod, 130 .fo_chown = invfo_chown, 131 .fo_sendfile = invfo_sendfile, 132 }; 133 134 static int knote_attach(struct knote *kn, struct kqueue *kq); 135 static void knote_drop(struct knote *kn, struct thread *td); 136 static void knote_enqueue(struct knote *kn); 137 static void knote_dequeue(struct knote *kn); 138 static void knote_init(void); 139 static struct knote *knote_alloc(int waitok); 140 static void knote_free(struct knote *kn); 141 142 static void filt_kqdetach(struct knote *kn); 143 static int filt_kqueue(struct knote *kn, long hint); 144 static int filt_procattach(struct knote *kn); 145 static void filt_procdetach(struct knote *kn); 146 static int filt_proc(struct knote *kn, long hint); 147 static int filt_fileattach(struct knote *kn); 148 static void filt_timerexpire(void *knx); 149 static int filt_timerattach(struct knote *kn); 150 static void filt_timerdetach(struct knote *kn); 151 static int filt_timer(struct knote *kn, long hint); 152 static int filt_userattach(struct knote *kn); 153 static void filt_userdetach(struct knote *kn); 154 static int filt_user(struct knote *kn, long hint); 155 static void filt_usertouch(struct knote *kn, struct kevent *kev, 156 u_long type); 157 158 static struct filterops file_filtops = { 159 .f_isfd = 1, 160 .f_attach = filt_fileattach, 161 }; 162 static struct filterops kqread_filtops = { 163 .f_isfd = 1, 164 .f_detach = filt_kqdetach, 165 .f_event = filt_kqueue, 166 }; 167 /* XXX - move to kern_proc.c? */ 168 static struct filterops proc_filtops = { 169 .f_isfd = 0, 170 .f_attach = filt_procattach, 171 .f_detach = filt_procdetach, 172 .f_event = filt_proc, 173 }; 174 static struct filterops timer_filtops = { 175 .f_isfd = 0, 176 .f_attach = filt_timerattach, 177 .f_detach = filt_timerdetach, 178 .f_event = filt_timer, 179 }; 180 static struct filterops user_filtops = { 181 .f_attach = filt_userattach, 182 .f_detach = filt_userdetach, 183 .f_event = filt_user, 184 .f_touch = filt_usertouch, 185 }; 186 187 static uma_zone_t knote_zone; 188 static atomic_uint kq_ncallouts = ATOMIC_VAR_INIT(0); 189 static unsigned int kq_calloutmax = 4 * 1024; 190 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 191 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 192 193 /* XXX - ensure not KN_INFLUX?? */ 194 #define KNOTE_ACTIVATE(kn, islock) do { \ 195 if ((islock)) \ 196 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 197 else \ 198 KQ_LOCK((kn)->kn_kq); \ 199 (kn)->kn_status |= KN_ACTIVE; \ 200 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 201 knote_enqueue((kn)); \ 202 if (!(islock)) \ 203 KQ_UNLOCK((kn)->kn_kq); \ 204 } while(0) 205 #define KQ_LOCK(kq) do { \ 206 mtx_lock(&(kq)->kq_lock); \ 207 } while (0) 208 #define KQ_FLUX_WAKEUP(kq) do { \ 209 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 210 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 211 wakeup((kq)); \ 212 } \ 213 } while (0) 214 #define KQ_UNLOCK_FLUX(kq) do { \ 215 KQ_FLUX_WAKEUP(kq); \ 216 mtx_unlock(&(kq)->kq_lock); \ 217 } while (0) 218 #define KQ_UNLOCK(kq) do { \ 219 mtx_unlock(&(kq)->kq_lock); \ 220 } while (0) 221 #define KQ_OWNED(kq) do { \ 222 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 223 } while (0) 224 #define KQ_NOTOWNED(kq) do { \ 225 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 226 } while (0) 227 #define KN_LIST_LOCK(kn) do { \ 228 if (kn->kn_knlist != NULL) \ 229 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \ 230 } while (0) 231 #define KN_LIST_UNLOCK(kn) do { \ 232 if (kn->kn_knlist != NULL) \ 233 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \ 234 } while (0) 235 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 236 if (islocked) \ 237 KNL_ASSERT_LOCKED(knl); \ 238 else \ 239 KNL_ASSERT_UNLOCKED(knl); \ 240 } while (0) 241 #ifdef INVARIANTS 242 #define KNL_ASSERT_LOCKED(knl) do { \ 243 knl->kl_assert_locked((knl)->kl_lockarg); \ 244 } while (0) 245 #define KNL_ASSERT_UNLOCKED(knl) do { \ 246 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 247 } while (0) 248 #else /* !INVARIANTS */ 249 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 250 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 251 #endif /* INVARIANTS */ 252 253 #define KN_HASHSIZE 64 /* XXX should be tunable */ 254 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 255 256 static int 257 filt_nullattach(struct knote *kn) 258 { 259 260 return (ENXIO); 261 }; 262 263 struct filterops null_filtops = { 264 .f_isfd = 0, 265 .f_attach = filt_nullattach, 266 }; 267 268 /* XXX - make SYSINIT to add these, and move into respective modules. */ 269 extern struct filterops sig_filtops; 270 extern struct filterops fs_filtops; 271 272 /* 273 * Table for for all system-defined filters. 274 */ 275 static struct mtx filterops_lock; 276 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 277 MTX_DEF); 278 static struct { 279 struct filterops *for_fop; 280 int for_refcnt; 281 } sysfilt_ops[EVFILT_SYSCOUNT] = { 282 { &file_filtops }, /* EVFILT_READ */ 283 { &file_filtops }, /* EVFILT_WRITE */ 284 { &null_filtops }, /* EVFILT_AIO */ 285 { &file_filtops }, /* EVFILT_VNODE */ 286 { &proc_filtops }, /* EVFILT_PROC */ 287 { &sig_filtops }, /* EVFILT_SIGNAL */ 288 { &timer_filtops }, /* EVFILT_TIMER */ 289 { &null_filtops }, /* former EVFILT_NETDEV */ 290 { &fs_filtops }, /* EVFILT_FS */ 291 { &null_filtops }, /* EVFILT_LIO */ 292 { &user_filtops }, /* EVFILT_USER */ 293 }; 294 295 /* 296 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 297 * method. 298 */ 299 static int 300 filt_fileattach(struct knote *kn) 301 { 302 303 return (fo_kqfilter(kn->kn_fp, kn)); 304 } 305 306 /*ARGSUSED*/ 307 static int 308 kqueue_kqfilter(struct file *fp, struct knote *kn) 309 { 310 struct kqueue *kq = kn->kn_fp->f_data; 311 312 if (kn->kn_filter != EVFILT_READ) 313 return (EINVAL); 314 315 kn->kn_status |= KN_KQUEUE; 316 kn->kn_fop = &kqread_filtops; 317 knlist_add(&kq->kq_sel.si_note, kn, 0); 318 319 return (0); 320 } 321 322 static void 323 filt_kqdetach(struct knote *kn) 324 { 325 struct kqueue *kq = kn->kn_fp->f_data; 326 327 knlist_remove(&kq->kq_sel.si_note, kn, 0); 328 } 329 330 /*ARGSUSED*/ 331 static int 332 filt_kqueue(struct knote *kn, long hint) 333 { 334 struct kqueue *kq = kn->kn_fp->f_data; 335 336 kn->kn_data = kq->kq_count; 337 return (kn->kn_data > 0); 338 } 339 340 /* XXX - move to kern_proc.c? */ 341 static int 342 filt_procattach(struct knote *kn) 343 { 344 struct proc *p; 345 int immediate; 346 int error; 347 348 immediate = 0; 349 p = pfind(kn->kn_id); 350 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 351 p = zpfind(kn->kn_id); 352 immediate = 1; 353 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 354 immediate = 1; 355 } 356 357 if (p == NULL) 358 return (ESRCH); 359 if ((error = p_cansee(curthread, p))) { 360 PROC_UNLOCK(p); 361 return (error); 362 } 363 364 kn->kn_ptr.p_proc = p; 365 kn->kn_flags |= EV_CLEAR; /* automatically set */ 366 367 /* 368 * internal flag indicating registration done by kernel 369 */ 370 if (kn->kn_flags & EV_FLAG1) { 371 kn->kn_data = kn->kn_sdata; /* ppid */ 372 kn->kn_fflags = NOTE_CHILD; 373 kn->kn_flags &= ~EV_FLAG1; 374 } 375 376 if (immediate == 0) 377 knlist_add(&p->p_klist, kn, 1); 378 379 /* 380 * Immediately activate any exit notes if the target process is a 381 * zombie. This is necessary to handle the case where the target 382 * process, e.g. a child, dies before the kevent is registered. 383 */ 384 if (immediate && filt_proc(kn, NOTE_EXIT)) 385 KNOTE_ACTIVATE(kn, 0); 386 387 PROC_UNLOCK(p); 388 389 return (0); 390 } 391 392 /* 393 * The knote may be attached to a different process, which may exit, 394 * leaving nothing for the knote to be attached to. So when the process 395 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 396 * it will be deleted when read out. However, as part of the knote deletion, 397 * this routine is called, so a check is needed to avoid actually performing 398 * a detach, because the original process does not exist any more. 399 */ 400 /* XXX - move to kern_proc.c? */ 401 static void 402 filt_procdetach(struct knote *kn) 403 { 404 struct proc *p; 405 406 p = kn->kn_ptr.p_proc; 407 knlist_remove(&p->p_klist, kn, 0); 408 kn->kn_ptr.p_proc = NULL; 409 } 410 411 /* XXX - move to kern_proc.c? */ 412 static int 413 filt_proc(struct knote *kn, long hint) 414 { 415 struct proc *p = kn->kn_ptr.p_proc; 416 u_int event; 417 418 /* 419 * mask off extra data 420 */ 421 event = (u_int)hint & NOTE_PCTRLMASK; 422 423 /* 424 * if the user is interested in this event, record it. 425 */ 426 if (kn->kn_sfflags & event) 427 kn->kn_fflags |= event; 428 429 /* 430 * process is gone, so flag the event as finished. 431 */ 432 if (event == NOTE_EXIT) { 433 if (!(kn->kn_status & KN_DETACHED)) 434 knlist_remove_inevent(&p->p_klist, kn); 435 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 436 kn->kn_ptr.p_proc = NULL; 437 if (kn->kn_fflags & NOTE_EXIT) 438 kn->kn_data = p->p_xstat; 439 if (kn->kn_fflags == 0) 440 kn->kn_flags |= EV_DROP; 441 return (1); 442 } 443 444 return (kn->kn_fflags != 0); 445 } 446 447 /* 448 * Called when the process forked. It mostly does the same as the 449 * knote(), activating all knotes registered to be activated when the 450 * process forked. Additionally, for each knote attached to the 451 * parent, check whether user wants to track the new process. If so 452 * attach a new knote to it, and immediately report an event with the 453 * child's pid. 454 */ 455 void 456 knote_fork(struct knlist *list, int pid) 457 { 458 struct kqueue *kq; 459 struct knote *kn; 460 struct kevent kev; 461 int error; 462 463 if (list == NULL) 464 return; 465 list->kl_lock(list->kl_lockarg); 466 467 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 468 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) 469 continue; 470 kq = kn->kn_kq; 471 KQ_LOCK(kq); 472 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 473 KQ_UNLOCK(kq); 474 continue; 475 } 476 477 /* 478 * The same as knote(), activate the event. 479 */ 480 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 481 kn->kn_status |= KN_HASKQLOCK; 482 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 483 KNOTE_ACTIVATE(kn, 1); 484 kn->kn_status &= ~KN_HASKQLOCK; 485 KQ_UNLOCK(kq); 486 continue; 487 } 488 489 /* 490 * The NOTE_TRACK case. In addition to the activation 491 * of the event, we need to register new event to 492 * track the child. Drop the locks in preparation for 493 * the call to kqueue_register(). 494 */ 495 kn->kn_status |= KN_INFLUX; 496 KQ_UNLOCK(kq); 497 list->kl_unlock(list->kl_lockarg); 498 499 /* 500 * Activate existing knote and register a knote with 501 * new process. 502 */ 503 kev.ident = pid; 504 kev.filter = kn->kn_filter; 505 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 506 kev.fflags = kn->kn_sfflags; 507 kev.data = kn->kn_id; /* parent */ 508 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 509 error = kqueue_register(kq, &kev, NULL, 0); 510 if (error) 511 kn->kn_fflags |= NOTE_TRACKERR; 512 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 513 KNOTE_ACTIVATE(kn, 0); 514 KQ_LOCK(kq); 515 kn->kn_status &= ~KN_INFLUX; 516 KQ_UNLOCK_FLUX(kq); 517 list->kl_lock(list->kl_lockarg); 518 } 519 list->kl_unlock(list->kl_lockarg); 520 } 521 522 /* 523 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 524 * interval timer support code. 525 */ 526 static __inline sbintime_t 527 timer2sbintime(intptr_t data) 528 { 529 530 return (SBT_1MS * data); 531 } 532 533 static void 534 filt_timerexpire(void *knx) 535 { 536 struct callout *calloutp; 537 struct knote *kn; 538 539 kn = knx; 540 kn->kn_data++; 541 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 542 543 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 544 calloutp = (struct callout *)kn->kn_hook; 545 callout_reset_sbt_on(calloutp, 546 timer2sbintime(kn->kn_sdata), 0 /* 1ms? */, 547 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 548 } 549 } 550 551 /* 552 * data contains amount of time to sleep, in milliseconds 553 */ 554 static int 555 filt_timerattach(struct knote *kn) 556 { 557 struct callout *calloutp; 558 sbintime_t to; 559 unsigned int ncallouts; 560 561 if ((intptr_t)kn->kn_sdata < 0) 562 return (EINVAL); 563 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 564 kn->kn_sdata = 1; 565 to = timer2sbintime(kn->kn_sdata); 566 if (to < 0) 567 return (EINVAL); 568 569 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed); 570 do { 571 if (ncallouts >= kq_calloutmax) 572 return (ENOMEM); 573 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts, 574 &ncallouts, ncallouts + 1, memory_order_relaxed, 575 memory_order_relaxed)); 576 577 kn->kn_flags |= EV_CLEAR; /* automatically set */ 578 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 579 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 580 callout_init(calloutp, CALLOUT_MPSAFE); 581 kn->kn_hook = calloutp; 582 callout_reset_sbt_on(calloutp, to, 0 /* 1ms? */, 583 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 584 585 return (0); 586 } 587 588 static void 589 filt_timerdetach(struct knote *kn) 590 { 591 struct callout *calloutp; 592 unsigned int old; 593 594 calloutp = (struct callout *)kn->kn_hook; 595 callout_drain(calloutp); 596 free(calloutp, M_KQUEUE); 597 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed); 598 KASSERT(old > 0, ("Number of callouts cannot become negative")); 599 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 600 } 601 602 static int 603 filt_timer(struct knote *kn, long hint) 604 { 605 606 return (kn->kn_data != 0); 607 } 608 609 static int 610 filt_userattach(struct knote *kn) 611 { 612 613 /* 614 * EVFILT_USER knotes are not attached to anything in the kernel. 615 */ 616 kn->kn_hook = NULL; 617 if (kn->kn_fflags & NOTE_TRIGGER) 618 kn->kn_hookid = 1; 619 else 620 kn->kn_hookid = 0; 621 return (0); 622 } 623 624 static void 625 filt_userdetach(__unused struct knote *kn) 626 { 627 628 /* 629 * EVFILT_USER knotes are not attached to anything in the kernel. 630 */ 631 } 632 633 static int 634 filt_user(struct knote *kn, __unused long hint) 635 { 636 637 return (kn->kn_hookid); 638 } 639 640 static void 641 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 642 { 643 u_int ffctrl; 644 645 switch (type) { 646 case EVENT_REGISTER: 647 if (kev->fflags & NOTE_TRIGGER) 648 kn->kn_hookid = 1; 649 650 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 651 kev->fflags &= NOTE_FFLAGSMASK; 652 switch (ffctrl) { 653 case NOTE_FFNOP: 654 break; 655 656 case NOTE_FFAND: 657 kn->kn_sfflags &= kev->fflags; 658 break; 659 660 case NOTE_FFOR: 661 kn->kn_sfflags |= kev->fflags; 662 break; 663 664 case NOTE_FFCOPY: 665 kn->kn_sfflags = kev->fflags; 666 break; 667 668 default: 669 /* XXX Return error? */ 670 break; 671 } 672 kn->kn_sdata = kev->data; 673 if (kev->flags & EV_CLEAR) { 674 kn->kn_hookid = 0; 675 kn->kn_data = 0; 676 kn->kn_fflags = 0; 677 } 678 break; 679 680 case EVENT_PROCESS: 681 *kev = kn->kn_kevent; 682 kev->fflags = kn->kn_sfflags; 683 kev->data = kn->kn_sdata; 684 if (kn->kn_flags & EV_CLEAR) { 685 kn->kn_hookid = 0; 686 kn->kn_data = 0; 687 kn->kn_fflags = 0; 688 } 689 break; 690 691 default: 692 panic("filt_usertouch() - invalid type (%ld)", type); 693 break; 694 } 695 } 696 697 int 698 sys_kqueue(struct thread *td, struct kqueue_args *uap) 699 { 700 struct filedesc *fdp; 701 struct kqueue *kq; 702 struct file *fp; 703 struct proc *p; 704 struct ucred *cred; 705 int fd, error; 706 707 p = td->td_proc; 708 cred = td->td_ucred; 709 crhold(cred); 710 PROC_LOCK(p); 711 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td->td_proc, 712 RLIMIT_KQUEUES))) { 713 PROC_UNLOCK(p); 714 crfree(cred); 715 return (ENOMEM); 716 } 717 PROC_UNLOCK(p); 718 719 fdp = p->p_fd; 720 error = falloc(td, &fp, &fd, 0); 721 if (error) 722 goto done2; 723 724 /* An extra reference on `fp' has been held for us by falloc(). */ 725 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 726 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 727 TAILQ_INIT(&kq->kq_head); 728 kq->kq_fdp = fdp; 729 kq->kq_cred = cred; 730 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 731 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 732 733 FILEDESC_XLOCK(fdp); 734 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 735 FILEDESC_XUNLOCK(fdp); 736 737 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 738 fdrop(fp, td); 739 740 td->td_retval[0] = fd; 741 done2: 742 if (error != 0) { 743 chgkqcnt(cred->cr_ruidinfo, -1, 0); 744 crfree(cred); 745 } 746 return (error); 747 } 748 749 #ifndef _SYS_SYSPROTO_H_ 750 struct kevent_args { 751 int fd; 752 const struct kevent *changelist; 753 int nchanges; 754 struct kevent *eventlist; 755 int nevents; 756 const struct timespec *timeout; 757 }; 758 #endif 759 int 760 sys_kevent(struct thread *td, struct kevent_args *uap) 761 { 762 struct timespec ts, *tsp; 763 struct kevent_copyops k_ops = { uap, 764 kevent_copyout, 765 kevent_copyin}; 766 int error; 767 #ifdef KTRACE 768 struct uio ktruio; 769 struct iovec ktriov; 770 struct uio *ktruioin = NULL; 771 struct uio *ktruioout = NULL; 772 #endif 773 774 if (uap->timeout != NULL) { 775 error = copyin(uap->timeout, &ts, sizeof(ts)); 776 if (error) 777 return (error); 778 tsp = &ts; 779 } else 780 tsp = NULL; 781 782 #ifdef KTRACE 783 if (KTRPOINT(td, KTR_GENIO)) { 784 ktriov.iov_base = uap->changelist; 785 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 786 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 787 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 788 .uio_td = td }; 789 ktruioin = cloneuio(&ktruio); 790 ktriov.iov_base = uap->eventlist; 791 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 792 ktruioout = cloneuio(&ktruio); 793 } 794 #endif 795 796 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 797 &k_ops, tsp); 798 799 #ifdef KTRACE 800 if (ktruioin != NULL) { 801 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 802 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 803 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 804 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 805 } 806 #endif 807 808 return (error); 809 } 810 811 /* 812 * Copy 'count' items into the destination list pointed to by uap->eventlist. 813 */ 814 static int 815 kevent_copyout(void *arg, struct kevent *kevp, int count) 816 { 817 struct kevent_args *uap; 818 int error; 819 820 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 821 uap = (struct kevent_args *)arg; 822 823 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 824 if (error == 0) 825 uap->eventlist += count; 826 return (error); 827 } 828 829 /* 830 * Copy 'count' items from the list pointed to by uap->changelist. 831 */ 832 static int 833 kevent_copyin(void *arg, struct kevent *kevp, int count) 834 { 835 struct kevent_args *uap; 836 int error; 837 838 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 839 uap = (struct kevent_args *)arg; 840 841 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 842 if (error == 0) 843 uap->changelist += count; 844 return (error); 845 } 846 847 int 848 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 849 struct kevent_copyops *k_ops, const struct timespec *timeout) 850 { 851 struct kevent keva[KQ_NEVENTS]; 852 struct kevent *kevp, *changes; 853 struct kqueue *kq; 854 struct file *fp; 855 cap_rights_t rights; 856 int i, n, nerrors, error; 857 858 cap_rights_init(&rights); 859 if (nchanges > 0) 860 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 861 if (nevents > 0) 862 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 863 error = fget(td, fd, &rights, &fp); 864 if (error != 0) 865 return (error); 866 867 error = kqueue_acquire(fp, &kq); 868 if (error != 0) 869 goto done_norel; 870 871 nerrors = 0; 872 873 while (nchanges > 0) { 874 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 875 error = k_ops->k_copyin(k_ops->arg, keva, n); 876 if (error) 877 goto done; 878 changes = keva; 879 for (i = 0; i < n; i++) { 880 kevp = &changes[i]; 881 if (!kevp->filter) 882 continue; 883 kevp->flags &= ~EV_SYSFLAGS; 884 error = kqueue_register(kq, kevp, td, 1); 885 if (error || (kevp->flags & EV_RECEIPT)) { 886 if (nevents != 0) { 887 kevp->flags = EV_ERROR; 888 kevp->data = error; 889 (void) k_ops->k_copyout(k_ops->arg, 890 kevp, 1); 891 nevents--; 892 nerrors++; 893 } else { 894 goto done; 895 } 896 } 897 } 898 nchanges -= n; 899 } 900 if (nerrors) { 901 td->td_retval[0] = nerrors; 902 error = 0; 903 goto done; 904 } 905 906 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 907 done: 908 kqueue_release(kq, 0); 909 done_norel: 910 fdrop(fp, td); 911 return (error); 912 } 913 914 int 915 kqueue_add_filteropts(int filt, struct filterops *filtops) 916 { 917 int error; 918 919 error = 0; 920 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 921 printf( 922 "trying to add a filterop that is out of range: %d is beyond %d\n", 923 ~filt, EVFILT_SYSCOUNT); 924 return EINVAL; 925 } 926 mtx_lock(&filterops_lock); 927 if (sysfilt_ops[~filt].for_fop != &null_filtops && 928 sysfilt_ops[~filt].for_fop != NULL) 929 error = EEXIST; 930 else { 931 sysfilt_ops[~filt].for_fop = filtops; 932 sysfilt_ops[~filt].for_refcnt = 0; 933 } 934 mtx_unlock(&filterops_lock); 935 936 return (error); 937 } 938 939 int 940 kqueue_del_filteropts(int filt) 941 { 942 int error; 943 944 error = 0; 945 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 946 return EINVAL; 947 948 mtx_lock(&filterops_lock); 949 if (sysfilt_ops[~filt].for_fop == &null_filtops || 950 sysfilt_ops[~filt].for_fop == NULL) 951 error = EINVAL; 952 else if (sysfilt_ops[~filt].for_refcnt != 0) 953 error = EBUSY; 954 else { 955 sysfilt_ops[~filt].for_fop = &null_filtops; 956 sysfilt_ops[~filt].for_refcnt = 0; 957 } 958 mtx_unlock(&filterops_lock); 959 960 return error; 961 } 962 963 static struct filterops * 964 kqueue_fo_find(int filt) 965 { 966 967 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 968 return NULL; 969 970 mtx_lock(&filterops_lock); 971 sysfilt_ops[~filt].for_refcnt++; 972 if (sysfilt_ops[~filt].for_fop == NULL) 973 sysfilt_ops[~filt].for_fop = &null_filtops; 974 mtx_unlock(&filterops_lock); 975 976 return sysfilt_ops[~filt].for_fop; 977 } 978 979 static void 980 kqueue_fo_release(int filt) 981 { 982 983 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 984 return; 985 986 mtx_lock(&filterops_lock); 987 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 988 ("filter object refcount not valid on release")); 989 sysfilt_ops[~filt].for_refcnt--; 990 mtx_unlock(&filterops_lock); 991 } 992 993 /* 994 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 995 * influence if memory allocation should wait. Make sure it is 0 if you 996 * hold any mutexes. 997 */ 998 static int 999 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1000 { 1001 struct filterops *fops; 1002 struct file *fp; 1003 struct knote *kn, *tkn; 1004 cap_rights_t rights; 1005 int error, filt, event; 1006 int haskqglobal, filedesc_unlock; 1007 1008 fp = NULL; 1009 kn = NULL; 1010 error = 0; 1011 haskqglobal = 0; 1012 filedesc_unlock = 0; 1013 1014 filt = kev->filter; 1015 fops = kqueue_fo_find(filt); 1016 if (fops == NULL) 1017 return EINVAL; 1018 1019 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1020 1021 findkn: 1022 if (fops->f_isfd) { 1023 KASSERT(td != NULL, ("td is NULL")); 1024 error = fget(td, kev->ident, 1025 cap_rights_init(&rights, CAP_EVENT), &fp); 1026 if (error) 1027 goto done; 1028 1029 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1030 kev->ident, 0) != 0) { 1031 /* try again */ 1032 fdrop(fp, td); 1033 fp = NULL; 1034 error = kqueue_expand(kq, fops, kev->ident, waitok); 1035 if (error) 1036 goto done; 1037 goto findkn; 1038 } 1039 1040 if (fp->f_type == DTYPE_KQUEUE) { 1041 /* 1042 * if we add some inteligence about what we are doing, 1043 * we should be able to support events on ourselves. 1044 * We need to know when we are doing this to prevent 1045 * getting both the knlist lock and the kq lock since 1046 * they are the same thing. 1047 */ 1048 if (fp->f_data == kq) { 1049 error = EINVAL; 1050 goto done; 1051 } 1052 1053 /* 1054 * Pre-lock the filedesc before the global 1055 * lock mutex, see the comment in 1056 * kqueue_close(). 1057 */ 1058 FILEDESC_XLOCK(td->td_proc->p_fd); 1059 filedesc_unlock = 1; 1060 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1061 } 1062 1063 KQ_LOCK(kq); 1064 if (kev->ident < kq->kq_knlistsize) { 1065 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1066 if (kev->filter == kn->kn_filter) 1067 break; 1068 } 1069 } else { 1070 if ((kev->flags & EV_ADD) == EV_ADD) 1071 kqueue_expand(kq, fops, kev->ident, waitok); 1072 1073 KQ_LOCK(kq); 1074 if (kq->kq_knhashmask != 0) { 1075 struct klist *list; 1076 1077 list = &kq->kq_knhash[ 1078 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1079 SLIST_FOREACH(kn, list, kn_link) 1080 if (kev->ident == kn->kn_id && 1081 kev->filter == kn->kn_filter) 1082 break; 1083 } 1084 } 1085 1086 /* knote is in the process of changing, wait for it to stablize. */ 1087 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1088 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1089 if (filedesc_unlock) { 1090 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1091 filedesc_unlock = 0; 1092 } 1093 kq->kq_state |= KQ_FLUXWAIT; 1094 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1095 if (fp != NULL) { 1096 fdrop(fp, td); 1097 fp = NULL; 1098 } 1099 goto findkn; 1100 } 1101 1102 /* 1103 * kn now contains the matching knote, or NULL if no match 1104 */ 1105 if (kn == NULL) { 1106 if (kev->flags & EV_ADD) { 1107 kn = tkn; 1108 tkn = NULL; 1109 if (kn == NULL) { 1110 KQ_UNLOCK(kq); 1111 error = ENOMEM; 1112 goto done; 1113 } 1114 kn->kn_fp = fp; 1115 kn->kn_kq = kq; 1116 kn->kn_fop = fops; 1117 /* 1118 * apply reference counts to knote structure, and 1119 * do not release it at the end of this routine. 1120 */ 1121 fops = NULL; 1122 fp = NULL; 1123 1124 kn->kn_sfflags = kev->fflags; 1125 kn->kn_sdata = kev->data; 1126 kev->fflags = 0; 1127 kev->data = 0; 1128 kn->kn_kevent = *kev; 1129 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1130 EV_ENABLE | EV_DISABLE); 1131 kn->kn_status = KN_INFLUX|KN_DETACHED; 1132 1133 error = knote_attach(kn, kq); 1134 KQ_UNLOCK(kq); 1135 if (error != 0) { 1136 tkn = kn; 1137 goto done; 1138 } 1139 1140 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1141 knote_drop(kn, td); 1142 goto done; 1143 } 1144 KN_LIST_LOCK(kn); 1145 goto done_ev_add; 1146 } else { 1147 /* No matching knote and the EV_ADD flag is not set. */ 1148 KQ_UNLOCK(kq); 1149 error = ENOENT; 1150 goto done; 1151 } 1152 } 1153 1154 if (kev->flags & EV_DELETE) { 1155 kn->kn_status |= KN_INFLUX; 1156 KQ_UNLOCK(kq); 1157 if (!(kn->kn_status & KN_DETACHED)) 1158 kn->kn_fop->f_detach(kn); 1159 knote_drop(kn, td); 1160 goto done; 1161 } 1162 1163 /* 1164 * The user may change some filter values after the initial EV_ADD, 1165 * but doing so will not reset any filter which has already been 1166 * triggered. 1167 */ 1168 kn->kn_status |= KN_INFLUX; 1169 KQ_UNLOCK(kq); 1170 KN_LIST_LOCK(kn); 1171 kn->kn_kevent.udata = kev->udata; 1172 if (!fops->f_isfd && fops->f_touch != NULL) { 1173 fops->f_touch(kn, kev, EVENT_REGISTER); 1174 } else { 1175 kn->kn_sfflags = kev->fflags; 1176 kn->kn_sdata = kev->data; 1177 } 1178 1179 /* 1180 * We can get here with kn->kn_knlist == NULL. This can happen when 1181 * the initial attach event decides that the event is "completed" 1182 * already. i.e. filt_procattach is called on a zombie process. It 1183 * will call filt_proc which will remove it from the list, and NULL 1184 * kn_knlist. 1185 */ 1186 done_ev_add: 1187 event = kn->kn_fop->f_event(kn, 0); 1188 KQ_LOCK(kq); 1189 if (event) 1190 KNOTE_ACTIVATE(kn, 1); 1191 kn->kn_status &= ~KN_INFLUX; 1192 KN_LIST_UNLOCK(kn); 1193 1194 if ((kev->flags & EV_DISABLE) && 1195 ((kn->kn_status & KN_DISABLED) == 0)) { 1196 kn->kn_status |= KN_DISABLED; 1197 } 1198 1199 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1200 kn->kn_status &= ~KN_DISABLED; 1201 if ((kn->kn_status & KN_ACTIVE) && 1202 ((kn->kn_status & KN_QUEUED) == 0)) 1203 knote_enqueue(kn); 1204 } 1205 KQ_UNLOCK_FLUX(kq); 1206 1207 done: 1208 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1209 if (filedesc_unlock) 1210 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1211 if (fp != NULL) 1212 fdrop(fp, td); 1213 if (tkn != NULL) 1214 knote_free(tkn); 1215 if (fops != NULL) 1216 kqueue_fo_release(filt); 1217 return (error); 1218 } 1219 1220 static int 1221 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1222 { 1223 int error; 1224 struct kqueue *kq; 1225 1226 error = 0; 1227 1228 kq = fp->f_data; 1229 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1230 return (EBADF); 1231 *kqp = kq; 1232 KQ_LOCK(kq); 1233 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1234 KQ_UNLOCK(kq); 1235 return (EBADF); 1236 } 1237 kq->kq_refcnt++; 1238 KQ_UNLOCK(kq); 1239 1240 return error; 1241 } 1242 1243 static void 1244 kqueue_release(struct kqueue *kq, int locked) 1245 { 1246 if (locked) 1247 KQ_OWNED(kq); 1248 else 1249 KQ_LOCK(kq); 1250 kq->kq_refcnt--; 1251 if (kq->kq_refcnt == 1) 1252 wakeup(&kq->kq_refcnt); 1253 if (!locked) 1254 KQ_UNLOCK(kq); 1255 } 1256 1257 static void 1258 kqueue_schedtask(struct kqueue *kq) 1259 { 1260 1261 KQ_OWNED(kq); 1262 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1263 ("scheduling kqueue task while draining")); 1264 1265 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1266 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1267 kq->kq_state |= KQ_TASKSCHED; 1268 } 1269 } 1270 1271 /* 1272 * Expand the kq to make sure we have storage for fops/ident pair. 1273 * 1274 * Return 0 on success (or no work necessary), return errno on failure. 1275 * 1276 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1277 * If kqueue_register is called from a non-fd context, there usually/should 1278 * be no locks held. 1279 */ 1280 static int 1281 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1282 int waitok) 1283 { 1284 struct klist *list, *tmp_knhash, *to_free; 1285 u_long tmp_knhashmask; 1286 int size; 1287 int fd; 1288 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1289 1290 KQ_NOTOWNED(kq); 1291 1292 to_free = NULL; 1293 if (fops->f_isfd) { 1294 fd = ident; 1295 if (kq->kq_knlistsize <= fd) { 1296 size = kq->kq_knlistsize; 1297 while (size <= fd) 1298 size += KQEXTENT; 1299 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1300 if (list == NULL) 1301 return ENOMEM; 1302 KQ_LOCK(kq); 1303 if (kq->kq_knlistsize > fd) { 1304 to_free = list; 1305 list = NULL; 1306 } else { 1307 if (kq->kq_knlist != NULL) { 1308 bcopy(kq->kq_knlist, list, 1309 kq->kq_knlistsize * sizeof(*list)); 1310 to_free = kq->kq_knlist; 1311 kq->kq_knlist = NULL; 1312 } 1313 bzero((caddr_t)list + 1314 kq->kq_knlistsize * sizeof(*list), 1315 (size - kq->kq_knlistsize) * sizeof(*list)); 1316 kq->kq_knlistsize = size; 1317 kq->kq_knlist = list; 1318 } 1319 KQ_UNLOCK(kq); 1320 } 1321 } else { 1322 if (kq->kq_knhashmask == 0) { 1323 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1324 &tmp_knhashmask); 1325 if (tmp_knhash == NULL) 1326 return ENOMEM; 1327 KQ_LOCK(kq); 1328 if (kq->kq_knhashmask == 0) { 1329 kq->kq_knhash = tmp_knhash; 1330 kq->kq_knhashmask = tmp_knhashmask; 1331 } else { 1332 to_free = tmp_knhash; 1333 } 1334 KQ_UNLOCK(kq); 1335 } 1336 } 1337 free(to_free, M_KQUEUE); 1338 1339 KQ_NOTOWNED(kq); 1340 return 0; 1341 } 1342 1343 static void 1344 kqueue_task(void *arg, int pending) 1345 { 1346 struct kqueue *kq; 1347 int haskqglobal; 1348 1349 haskqglobal = 0; 1350 kq = arg; 1351 1352 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1353 KQ_LOCK(kq); 1354 1355 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1356 1357 kq->kq_state &= ~KQ_TASKSCHED; 1358 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1359 wakeup(&kq->kq_state); 1360 } 1361 KQ_UNLOCK(kq); 1362 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1363 } 1364 1365 /* 1366 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1367 * We treat KN_MARKER knotes as if they are INFLUX. 1368 */ 1369 static int 1370 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1371 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1372 { 1373 struct kevent *kevp; 1374 struct knote *kn, *marker; 1375 sbintime_t asbt, rsbt; 1376 int count, error, haskqglobal, influx, nkev, touch; 1377 1378 count = maxevents; 1379 nkev = 0; 1380 error = 0; 1381 haskqglobal = 0; 1382 1383 if (maxevents == 0) 1384 goto done_nl; 1385 1386 rsbt = 0; 1387 if (tsp != NULL) { 1388 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1389 tsp->tv_nsec >= 1000000000) { 1390 error = EINVAL; 1391 goto done_nl; 1392 } 1393 if (timespecisset(tsp)) { 1394 if (tsp->tv_sec <= INT32_MAX) { 1395 rsbt = tstosbt(*tsp); 1396 if (TIMESEL(&asbt, rsbt)) 1397 asbt += tc_tick_sbt; 1398 if (asbt <= INT64_MAX - rsbt) 1399 asbt += rsbt; 1400 else 1401 asbt = 0; 1402 rsbt >>= tc_precexp; 1403 } else 1404 asbt = 0; 1405 } else 1406 asbt = -1; 1407 } else 1408 asbt = 0; 1409 marker = knote_alloc(1); 1410 if (marker == NULL) { 1411 error = ENOMEM; 1412 goto done_nl; 1413 } 1414 marker->kn_status = KN_MARKER; 1415 KQ_LOCK(kq); 1416 1417 retry: 1418 kevp = keva; 1419 if (kq->kq_count == 0) { 1420 if (asbt == -1) { 1421 error = EWOULDBLOCK; 1422 } else { 1423 kq->kq_state |= KQ_SLEEP; 1424 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1425 "kqread", asbt, rsbt, C_ABSOLUTE); 1426 } 1427 if (error == 0) 1428 goto retry; 1429 /* don't restart after signals... */ 1430 if (error == ERESTART) 1431 error = EINTR; 1432 else if (error == EWOULDBLOCK) 1433 error = 0; 1434 goto done; 1435 } 1436 1437 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1438 influx = 0; 1439 while (count) { 1440 KQ_OWNED(kq); 1441 kn = TAILQ_FIRST(&kq->kq_head); 1442 1443 if ((kn->kn_status == KN_MARKER && kn != marker) || 1444 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1445 if (influx) { 1446 influx = 0; 1447 KQ_FLUX_WAKEUP(kq); 1448 } 1449 kq->kq_state |= KQ_FLUXWAIT; 1450 error = msleep(kq, &kq->kq_lock, PSOCK, 1451 "kqflxwt", 0); 1452 continue; 1453 } 1454 1455 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1456 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1457 kn->kn_status &= ~KN_QUEUED; 1458 kq->kq_count--; 1459 continue; 1460 } 1461 if (kn == marker) { 1462 KQ_FLUX_WAKEUP(kq); 1463 if (count == maxevents) 1464 goto retry; 1465 goto done; 1466 } 1467 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1468 ("KN_INFLUX set when not suppose to be")); 1469 1470 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1471 kn->kn_status &= ~KN_QUEUED; 1472 kn->kn_status |= KN_INFLUX; 1473 kq->kq_count--; 1474 KQ_UNLOCK(kq); 1475 /* 1476 * We don't need to lock the list since we've marked 1477 * it _INFLUX. 1478 */ 1479 if (!(kn->kn_status & KN_DETACHED)) 1480 kn->kn_fop->f_detach(kn); 1481 knote_drop(kn, td); 1482 KQ_LOCK(kq); 1483 continue; 1484 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1485 kn->kn_status &= ~KN_QUEUED; 1486 kn->kn_status |= KN_INFLUX; 1487 kq->kq_count--; 1488 KQ_UNLOCK(kq); 1489 /* 1490 * We don't need to lock the list since we've marked 1491 * it _INFLUX. 1492 */ 1493 *kevp = kn->kn_kevent; 1494 if (!(kn->kn_status & KN_DETACHED)) 1495 kn->kn_fop->f_detach(kn); 1496 knote_drop(kn, td); 1497 KQ_LOCK(kq); 1498 kn = NULL; 1499 } else { 1500 kn->kn_status |= KN_INFLUX; 1501 KQ_UNLOCK(kq); 1502 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1503 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1504 KN_LIST_LOCK(kn); 1505 if (kn->kn_fop->f_event(kn, 0) == 0) { 1506 KQ_LOCK(kq); 1507 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1508 kn->kn_status &= 1509 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX); 1510 kq->kq_count--; 1511 KN_LIST_UNLOCK(kn); 1512 influx = 1; 1513 continue; 1514 } 1515 touch = (!kn->kn_fop->f_isfd && 1516 kn->kn_fop->f_touch != NULL); 1517 if (touch) 1518 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1519 else 1520 *kevp = kn->kn_kevent; 1521 KQ_LOCK(kq); 1522 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1523 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1524 /* 1525 * Manually clear knotes who weren't 1526 * 'touch'ed. 1527 */ 1528 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1529 kn->kn_data = 0; 1530 kn->kn_fflags = 0; 1531 } 1532 if (kn->kn_flags & EV_DISPATCH) 1533 kn->kn_status |= KN_DISABLED; 1534 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1535 kq->kq_count--; 1536 } else 1537 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1538 1539 kn->kn_status &= ~(KN_INFLUX); 1540 KN_LIST_UNLOCK(kn); 1541 influx = 1; 1542 } 1543 1544 /* we are returning a copy to the user */ 1545 kevp++; 1546 nkev++; 1547 count--; 1548 1549 if (nkev == KQ_NEVENTS) { 1550 influx = 0; 1551 KQ_UNLOCK_FLUX(kq); 1552 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1553 nkev = 0; 1554 kevp = keva; 1555 KQ_LOCK(kq); 1556 if (error) 1557 break; 1558 } 1559 } 1560 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1561 done: 1562 KQ_OWNED(kq); 1563 KQ_UNLOCK_FLUX(kq); 1564 knote_free(marker); 1565 done_nl: 1566 KQ_NOTOWNED(kq); 1567 if (nkev != 0) 1568 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1569 td->td_retval[0] = maxevents - count; 1570 return (error); 1571 } 1572 1573 /* 1574 * XXX 1575 * This could be expanded to call kqueue_scan, if desired. 1576 */ 1577 /*ARGSUSED*/ 1578 static int 1579 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1580 int flags, struct thread *td) 1581 { 1582 return (ENXIO); 1583 } 1584 1585 /*ARGSUSED*/ 1586 static int 1587 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1588 int flags, struct thread *td) 1589 { 1590 return (ENXIO); 1591 } 1592 1593 /*ARGSUSED*/ 1594 static int 1595 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1596 struct thread *td) 1597 { 1598 1599 return (EINVAL); 1600 } 1601 1602 /*ARGSUSED*/ 1603 static int 1604 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1605 struct ucred *active_cred, struct thread *td) 1606 { 1607 /* 1608 * Enabling sigio causes two major problems: 1609 * 1) infinite recursion: 1610 * Synopsys: kevent is being used to track signals and have FIOASYNC 1611 * set. On receipt of a signal this will cause a kqueue to recurse 1612 * into itself over and over. Sending the sigio causes the kqueue 1613 * to become ready, which in turn posts sigio again, forever. 1614 * Solution: this can be solved by setting a flag in the kqueue that 1615 * we have a SIGIO in progress. 1616 * 2) locking problems: 1617 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1618 * us above the proc and pgrp locks. 1619 * Solution: Post a signal using an async mechanism, being sure to 1620 * record a generation count in the delivery so that we do not deliver 1621 * a signal to the wrong process. 1622 * 1623 * Note, these two mechanisms are somewhat mutually exclusive! 1624 */ 1625 #if 0 1626 struct kqueue *kq; 1627 1628 kq = fp->f_data; 1629 switch (cmd) { 1630 case FIOASYNC: 1631 if (*(int *)data) { 1632 kq->kq_state |= KQ_ASYNC; 1633 } else { 1634 kq->kq_state &= ~KQ_ASYNC; 1635 } 1636 return (0); 1637 1638 case FIOSETOWN: 1639 return (fsetown(*(int *)data, &kq->kq_sigio)); 1640 1641 case FIOGETOWN: 1642 *(int *)data = fgetown(&kq->kq_sigio); 1643 return (0); 1644 } 1645 #endif 1646 1647 return (ENOTTY); 1648 } 1649 1650 /*ARGSUSED*/ 1651 static int 1652 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1653 struct thread *td) 1654 { 1655 struct kqueue *kq; 1656 int revents = 0; 1657 int error; 1658 1659 if ((error = kqueue_acquire(fp, &kq))) 1660 return POLLERR; 1661 1662 KQ_LOCK(kq); 1663 if (events & (POLLIN | POLLRDNORM)) { 1664 if (kq->kq_count) { 1665 revents |= events & (POLLIN | POLLRDNORM); 1666 } else { 1667 selrecord(td, &kq->kq_sel); 1668 if (SEL_WAITING(&kq->kq_sel)) 1669 kq->kq_state |= KQ_SEL; 1670 } 1671 } 1672 kqueue_release(kq, 1); 1673 KQ_UNLOCK(kq); 1674 return (revents); 1675 } 1676 1677 /*ARGSUSED*/ 1678 static int 1679 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1680 struct thread *td) 1681 { 1682 1683 bzero((void *)st, sizeof *st); 1684 /* 1685 * We no longer return kq_count because the unlocked value is useless. 1686 * If you spent all this time getting the count, why not spend your 1687 * syscall better by calling kevent? 1688 * 1689 * XXX - This is needed for libc_r. 1690 */ 1691 st->st_mode = S_IFIFO; 1692 return (0); 1693 } 1694 1695 /*ARGSUSED*/ 1696 static int 1697 kqueue_close(struct file *fp, struct thread *td) 1698 { 1699 struct kqueue *kq = fp->f_data; 1700 struct filedesc *fdp; 1701 struct knote *kn; 1702 int i; 1703 int error; 1704 int filedesc_unlock; 1705 1706 if ((error = kqueue_acquire(fp, &kq))) 1707 return error; 1708 1709 filedesc_unlock = 0; 1710 KQ_LOCK(kq); 1711 1712 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1713 ("kqueue already closing")); 1714 kq->kq_state |= KQ_CLOSING; 1715 if (kq->kq_refcnt > 1) 1716 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1717 1718 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1719 fdp = kq->kq_fdp; 1720 1721 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1722 ("kqueue's knlist not empty")); 1723 1724 for (i = 0; i < kq->kq_knlistsize; i++) { 1725 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1726 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1727 kq->kq_state |= KQ_FLUXWAIT; 1728 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1729 continue; 1730 } 1731 kn->kn_status |= KN_INFLUX; 1732 KQ_UNLOCK(kq); 1733 if (!(kn->kn_status & KN_DETACHED)) 1734 kn->kn_fop->f_detach(kn); 1735 knote_drop(kn, td); 1736 KQ_LOCK(kq); 1737 } 1738 } 1739 if (kq->kq_knhashmask != 0) { 1740 for (i = 0; i <= kq->kq_knhashmask; i++) { 1741 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1742 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1743 kq->kq_state |= KQ_FLUXWAIT; 1744 msleep(kq, &kq->kq_lock, PSOCK, 1745 "kqclo2", 0); 1746 continue; 1747 } 1748 kn->kn_status |= KN_INFLUX; 1749 KQ_UNLOCK(kq); 1750 if (!(kn->kn_status & KN_DETACHED)) 1751 kn->kn_fop->f_detach(kn); 1752 knote_drop(kn, td); 1753 KQ_LOCK(kq); 1754 } 1755 } 1756 } 1757 1758 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1759 kq->kq_state |= KQ_TASKDRAIN; 1760 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1761 } 1762 1763 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1764 selwakeuppri(&kq->kq_sel, PSOCK); 1765 if (!SEL_WAITING(&kq->kq_sel)) 1766 kq->kq_state &= ~KQ_SEL; 1767 } 1768 1769 KQ_UNLOCK(kq); 1770 1771 /* 1772 * We could be called due to the knote_drop() doing fdrop(), 1773 * called from kqueue_register(). In this case the global 1774 * lock is owned, and filedesc sx is locked before, to not 1775 * take the sleepable lock after non-sleepable. 1776 */ 1777 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1778 FILEDESC_XLOCK(fdp); 1779 filedesc_unlock = 1; 1780 } else 1781 filedesc_unlock = 0; 1782 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1783 if (filedesc_unlock) 1784 FILEDESC_XUNLOCK(fdp); 1785 1786 seldrain(&kq->kq_sel); 1787 knlist_destroy(&kq->kq_sel.si_note); 1788 mtx_destroy(&kq->kq_lock); 1789 kq->kq_fdp = NULL; 1790 1791 if (kq->kq_knhash != NULL) 1792 free(kq->kq_knhash, M_KQUEUE); 1793 if (kq->kq_knlist != NULL) 1794 free(kq->kq_knlist, M_KQUEUE); 1795 1796 funsetown(&kq->kq_sigio); 1797 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 1798 crfree(kq->kq_cred); 1799 free(kq, M_KQUEUE); 1800 fp->f_data = NULL; 1801 1802 return (0); 1803 } 1804 1805 static void 1806 kqueue_wakeup(struct kqueue *kq) 1807 { 1808 KQ_OWNED(kq); 1809 1810 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1811 kq->kq_state &= ~KQ_SLEEP; 1812 wakeup(kq); 1813 } 1814 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1815 selwakeuppri(&kq->kq_sel, PSOCK); 1816 if (!SEL_WAITING(&kq->kq_sel)) 1817 kq->kq_state &= ~KQ_SEL; 1818 } 1819 if (!knlist_empty(&kq->kq_sel.si_note)) 1820 kqueue_schedtask(kq); 1821 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1822 pgsigio(&kq->kq_sigio, SIGIO, 0); 1823 } 1824 } 1825 1826 /* 1827 * Walk down a list of knotes, activating them if their event has triggered. 1828 * 1829 * There is a possibility to optimize in the case of one kq watching another. 1830 * Instead of scheduling a task to wake it up, you could pass enough state 1831 * down the chain to make up the parent kqueue. Make this code functional 1832 * first. 1833 */ 1834 void 1835 knote(struct knlist *list, long hint, int lockflags) 1836 { 1837 struct kqueue *kq; 1838 struct knote *kn; 1839 int error; 1840 1841 if (list == NULL) 1842 return; 1843 1844 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1845 1846 if ((lockflags & KNF_LISTLOCKED) == 0) 1847 list->kl_lock(list->kl_lockarg); 1848 1849 /* 1850 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1851 * the kqueue scheduling, but this will introduce four 1852 * lock/unlock's for each knote to test. If we do, continue to use 1853 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1854 * only safe if you want to remove the current item, which we are 1855 * not doing. 1856 */ 1857 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1858 kq = kn->kn_kq; 1859 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { 1860 KQ_LOCK(kq); 1861 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1862 KQ_UNLOCK(kq); 1863 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1864 kn->kn_status |= KN_INFLUX; 1865 KQ_UNLOCK(kq); 1866 error = kn->kn_fop->f_event(kn, hint); 1867 KQ_LOCK(kq); 1868 kn->kn_status &= ~KN_INFLUX; 1869 if (error) 1870 KNOTE_ACTIVATE(kn, 1); 1871 KQ_UNLOCK_FLUX(kq); 1872 } else { 1873 kn->kn_status |= KN_HASKQLOCK; 1874 if (kn->kn_fop->f_event(kn, hint)) 1875 KNOTE_ACTIVATE(kn, 1); 1876 kn->kn_status &= ~KN_HASKQLOCK; 1877 KQ_UNLOCK(kq); 1878 } 1879 } 1880 kq = NULL; 1881 } 1882 if ((lockflags & KNF_LISTLOCKED) == 0) 1883 list->kl_unlock(list->kl_lockarg); 1884 } 1885 1886 /* 1887 * add a knote to a knlist 1888 */ 1889 void 1890 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1891 { 1892 KNL_ASSERT_LOCK(knl, islocked); 1893 KQ_NOTOWNED(kn->kn_kq); 1894 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1895 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1896 if (!islocked) 1897 knl->kl_lock(knl->kl_lockarg); 1898 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1899 if (!islocked) 1900 knl->kl_unlock(knl->kl_lockarg); 1901 KQ_LOCK(kn->kn_kq); 1902 kn->kn_knlist = knl; 1903 kn->kn_status &= ~KN_DETACHED; 1904 KQ_UNLOCK(kn->kn_kq); 1905 } 1906 1907 static void 1908 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1909 { 1910 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1911 KNL_ASSERT_LOCK(knl, knlislocked); 1912 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1913 if (!kqislocked) 1914 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1915 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1916 if (!knlislocked) 1917 knl->kl_lock(knl->kl_lockarg); 1918 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1919 kn->kn_knlist = NULL; 1920 if (!knlislocked) 1921 knl->kl_unlock(knl->kl_lockarg); 1922 if (!kqislocked) 1923 KQ_LOCK(kn->kn_kq); 1924 kn->kn_status |= KN_DETACHED; 1925 if (!kqislocked) 1926 KQ_UNLOCK(kn->kn_kq); 1927 } 1928 1929 /* 1930 * remove knote from the specified knlist 1931 */ 1932 void 1933 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1934 { 1935 1936 knlist_remove_kq(knl, kn, islocked, 0); 1937 } 1938 1939 /* 1940 * remove knote from the specified knlist while in f_event handler. 1941 */ 1942 void 1943 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1944 { 1945 1946 knlist_remove_kq(knl, kn, 1, 1947 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1948 } 1949 1950 int 1951 knlist_empty(struct knlist *knl) 1952 { 1953 1954 KNL_ASSERT_LOCKED(knl); 1955 return SLIST_EMPTY(&knl->kl_list); 1956 } 1957 1958 static struct mtx knlist_lock; 1959 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1960 MTX_DEF); 1961 static void knlist_mtx_lock(void *arg); 1962 static void knlist_mtx_unlock(void *arg); 1963 1964 static void 1965 knlist_mtx_lock(void *arg) 1966 { 1967 1968 mtx_lock((struct mtx *)arg); 1969 } 1970 1971 static void 1972 knlist_mtx_unlock(void *arg) 1973 { 1974 1975 mtx_unlock((struct mtx *)arg); 1976 } 1977 1978 static void 1979 knlist_mtx_assert_locked(void *arg) 1980 { 1981 1982 mtx_assert((struct mtx *)arg, MA_OWNED); 1983 } 1984 1985 static void 1986 knlist_mtx_assert_unlocked(void *arg) 1987 { 1988 1989 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 1990 } 1991 1992 static void 1993 knlist_rw_rlock(void *arg) 1994 { 1995 1996 rw_rlock((struct rwlock *)arg); 1997 } 1998 1999 static void 2000 knlist_rw_runlock(void *arg) 2001 { 2002 2003 rw_runlock((struct rwlock *)arg); 2004 } 2005 2006 static void 2007 knlist_rw_assert_locked(void *arg) 2008 { 2009 2010 rw_assert((struct rwlock *)arg, RA_LOCKED); 2011 } 2012 2013 static void 2014 knlist_rw_assert_unlocked(void *arg) 2015 { 2016 2017 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2018 } 2019 2020 void 2021 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2022 void (*kl_unlock)(void *), 2023 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2024 { 2025 2026 if (lock == NULL) 2027 knl->kl_lockarg = &knlist_lock; 2028 else 2029 knl->kl_lockarg = lock; 2030 2031 if (kl_lock == NULL) 2032 knl->kl_lock = knlist_mtx_lock; 2033 else 2034 knl->kl_lock = kl_lock; 2035 if (kl_unlock == NULL) 2036 knl->kl_unlock = knlist_mtx_unlock; 2037 else 2038 knl->kl_unlock = kl_unlock; 2039 if (kl_assert_locked == NULL) 2040 knl->kl_assert_locked = knlist_mtx_assert_locked; 2041 else 2042 knl->kl_assert_locked = kl_assert_locked; 2043 if (kl_assert_unlocked == NULL) 2044 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2045 else 2046 knl->kl_assert_unlocked = kl_assert_unlocked; 2047 2048 SLIST_INIT(&knl->kl_list); 2049 } 2050 2051 void 2052 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2053 { 2054 2055 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2056 } 2057 2058 void 2059 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2060 { 2061 2062 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2063 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2064 } 2065 2066 void 2067 knlist_destroy(struct knlist *knl) 2068 { 2069 2070 #ifdef INVARIANTS 2071 /* 2072 * if we run across this error, we need to find the offending 2073 * driver and have it call knlist_clear or knlist_delete. 2074 */ 2075 if (!SLIST_EMPTY(&knl->kl_list)) 2076 printf("WARNING: destroying knlist w/ knotes on it!\n"); 2077 #endif 2078 2079 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 2080 SLIST_INIT(&knl->kl_list); 2081 } 2082 2083 /* 2084 * Even if we are locked, we may need to drop the lock to allow any influx 2085 * knotes time to "settle". 2086 */ 2087 void 2088 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2089 { 2090 struct knote *kn, *kn2; 2091 struct kqueue *kq; 2092 2093 if (islocked) 2094 KNL_ASSERT_LOCKED(knl); 2095 else { 2096 KNL_ASSERT_UNLOCKED(knl); 2097 again: /* need to reacquire lock since we have dropped it */ 2098 knl->kl_lock(knl->kl_lockarg); 2099 } 2100 2101 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2102 kq = kn->kn_kq; 2103 KQ_LOCK(kq); 2104 if ((kn->kn_status & KN_INFLUX)) { 2105 KQ_UNLOCK(kq); 2106 continue; 2107 } 2108 knlist_remove_kq(knl, kn, 1, 1); 2109 if (killkn) { 2110 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2111 KQ_UNLOCK(kq); 2112 knote_drop(kn, td); 2113 } else { 2114 /* Make sure cleared knotes disappear soon */ 2115 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2116 KQ_UNLOCK(kq); 2117 } 2118 kq = NULL; 2119 } 2120 2121 if (!SLIST_EMPTY(&knl->kl_list)) { 2122 /* there are still KN_INFLUX remaining */ 2123 kn = SLIST_FIRST(&knl->kl_list); 2124 kq = kn->kn_kq; 2125 KQ_LOCK(kq); 2126 KASSERT(kn->kn_status & KN_INFLUX, 2127 ("knote removed w/o list lock")); 2128 knl->kl_unlock(knl->kl_lockarg); 2129 kq->kq_state |= KQ_FLUXWAIT; 2130 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2131 kq = NULL; 2132 goto again; 2133 } 2134 2135 if (islocked) 2136 KNL_ASSERT_LOCKED(knl); 2137 else { 2138 knl->kl_unlock(knl->kl_lockarg); 2139 KNL_ASSERT_UNLOCKED(knl); 2140 } 2141 } 2142 2143 /* 2144 * Remove all knotes referencing a specified fd must be called with FILEDESC 2145 * lock. This prevents a race where a new fd comes along and occupies the 2146 * entry and we attach a knote to the fd. 2147 */ 2148 void 2149 knote_fdclose(struct thread *td, int fd) 2150 { 2151 struct filedesc *fdp = td->td_proc->p_fd; 2152 struct kqueue *kq; 2153 struct knote *kn; 2154 int influx; 2155 2156 FILEDESC_XLOCK_ASSERT(fdp); 2157 2158 /* 2159 * We shouldn't have to worry about new kevents appearing on fd 2160 * since filedesc is locked. 2161 */ 2162 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2163 KQ_LOCK(kq); 2164 2165 again: 2166 influx = 0; 2167 while (kq->kq_knlistsize > fd && 2168 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2169 if (kn->kn_status & KN_INFLUX) { 2170 /* someone else might be waiting on our knote */ 2171 if (influx) 2172 wakeup(kq); 2173 kq->kq_state |= KQ_FLUXWAIT; 2174 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2175 goto again; 2176 } 2177 kn->kn_status |= KN_INFLUX; 2178 KQ_UNLOCK(kq); 2179 if (!(kn->kn_status & KN_DETACHED)) 2180 kn->kn_fop->f_detach(kn); 2181 knote_drop(kn, td); 2182 influx = 1; 2183 KQ_LOCK(kq); 2184 } 2185 KQ_UNLOCK_FLUX(kq); 2186 } 2187 } 2188 2189 static int 2190 knote_attach(struct knote *kn, struct kqueue *kq) 2191 { 2192 struct klist *list; 2193 2194 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2195 KQ_OWNED(kq); 2196 2197 if (kn->kn_fop->f_isfd) { 2198 if (kn->kn_id >= kq->kq_knlistsize) 2199 return ENOMEM; 2200 list = &kq->kq_knlist[kn->kn_id]; 2201 } else { 2202 if (kq->kq_knhash == NULL) 2203 return ENOMEM; 2204 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2205 } 2206 2207 SLIST_INSERT_HEAD(list, kn, kn_link); 2208 2209 return 0; 2210 } 2211 2212 /* 2213 * knote must already have been detached using the f_detach method. 2214 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2215 * to prevent other removal. 2216 */ 2217 static void 2218 knote_drop(struct knote *kn, struct thread *td) 2219 { 2220 struct kqueue *kq; 2221 struct klist *list; 2222 2223 kq = kn->kn_kq; 2224 2225 KQ_NOTOWNED(kq); 2226 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2227 ("knote_drop called without KN_INFLUX set in kn_status")); 2228 2229 KQ_LOCK(kq); 2230 if (kn->kn_fop->f_isfd) 2231 list = &kq->kq_knlist[kn->kn_id]; 2232 else 2233 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2234 2235 if (!SLIST_EMPTY(list)) 2236 SLIST_REMOVE(list, kn, knote, kn_link); 2237 if (kn->kn_status & KN_QUEUED) 2238 knote_dequeue(kn); 2239 KQ_UNLOCK_FLUX(kq); 2240 2241 if (kn->kn_fop->f_isfd) { 2242 fdrop(kn->kn_fp, td); 2243 kn->kn_fp = NULL; 2244 } 2245 kqueue_fo_release(kn->kn_kevent.filter); 2246 kn->kn_fop = NULL; 2247 knote_free(kn); 2248 } 2249 2250 static void 2251 knote_enqueue(struct knote *kn) 2252 { 2253 struct kqueue *kq = kn->kn_kq; 2254 2255 KQ_OWNED(kn->kn_kq); 2256 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2257 2258 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2259 kn->kn_status |= KN_QUEUED; 2260 kq->kq_count++; 2261 kqueue_wakeup(kq); 2262 } 2263 2264 static void 2265 knote_dequeue(struct knote *kn) 2266 { 2267 struct kqueue *kq = kn->kn_kq; 2268 2269 KQ_OWNED(kn->kn_kq); 2270 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2271 2272 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2273 kn->kn_status &= ~KN_QUEUED; 2274 kq->kq_count--; 2275 } 2276 2277 static void 2278 knote_init(void) 2279 { 2280 2281 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2282 NULL, NULL, UMA_ALIGN_PTR, 0); 2283 } 2284 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2285 2286 static struct knote * 2287 knote_alloc(int waitok) 2288 { 2289 return ((struct knote *)uma_zalloc(knote_zone, 2290 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2291 } 2292 2293 static void 2294 knote_free(struct knote *kn) 2295 { 2296 if (kn != NULL) 2297 uma_zfree(knote_zone, kn); 2298 } 2299 2300 /* 2301 * Register the kev w/ the kq specified by fd. 2302 */ 2303 int 2304 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2305 { 2306 struct kqueue *kq; 2307 struct file *fp; 2308 cap_rights_t rights; 2309 int error; 2310 2311 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2312 if (error != 0) 2313 return (error); 2314 if ((error = kqueue_acquire(fp, &kq)) != 0) 2315 goto noacquire; 2316 2317 error = kqueue_register(kq, kev, td, waitok); 2318 2319 kqueue_release(kq, 0); 2320 2321 noacquire: 2322 fdrop(fp, td); 2323 2324 return error; 2325 } 2326