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 error = fget(td, fd, cap_rights_init(&rights, CAP_POST_EVENT), &fp); 859 if (error != 0) 860 return (error); 861 if ((error = kqueue_acquire(fp, &kq)) != 0) 862 goto done_norel; 863 864 nerrors = 0; 865 866 while (nchanges > 0) { 867 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 868 error = k_ops->k_copyin(k_ops->arg, keva, n); 869 if (error) 870 goto done; 871 changes = keva; 872 for (i = 0; i < n; i++) { 873 kevp = &changes[i]; 874 if (!kevp->filter) 875 continue; 876 kevp->flags &= ~EV_SYSFLAGS; 877 error = kqueue_register(kq, kevp, td, 1); 878 if (error || (kevp->flags & EV_RECEIPT)) { 879 if (nevents != 0) { 880 kevp->flags = EV_ERROR; 881 kevp->data = error; 882 (void) k_ops->k_copyout(k_ops->arg, 883 kevp, 1); 884 nevents--; 885 nerrors++; 886 } else { 887 goto done; 888 } 889 } 890 } 891 nchanges -= n; 892 } 893 if (nerrors) { 894 td->td_retval[0] = nerrors; 895 error = 0; 896 goto done; 897 } 898 899 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 900 done: 901 kqueue_release(kq, 0); 902 done_norel: 903 fdrop(fp, td); 904 return (error); 905 } 906 907 int 908 kqueue_add_filteropts(int filt, struct filterops *filtops) 909 { 910 int error; 911 912 error = 0; 913 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 914 printf( 915 "trying to add a filterop that is out of range: %d is beyond %d\n", 916 ~filt, EVFILT_SYSCOUNT); 917 return EINVAL; 918 } 919 mtx_lock(&filterops_lock); 920 if (sysfilt_ops[~filt].for_fop != &null_filtops && 921 sysfilt_ops[~filt].for_fop != NULL) 922 error = EEXIST; 923 else { 924 sysfilt_ops[~filt].for_fop = filtops; 925 sysfilt_ops[~filt].for_refcnt = 0; 926 } 927 mtx_unlock(&filterops_lock); 928 929 return (error); 930 } 931 932 int 933 kqueue_del_filteropts(int filt) 934 { 935 int error; 936 937 error = 0; 938 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 939 return EINVAL; 940 941 mtx_lock(&filterops_lock); 942 if (sysfilt_ops[~filt].for_fop == &null_filtops || 943 sysfilt_ops[~filt].for_fop == NULL) 944 error = EINVAL; 945 else if (sysfilt_ops[~filt].for_refcnt != 0) 946 error = EBUSY; 947 else { 948 sysfilt_ops[~filt].for_fop = &null_filtops; 949 sysfilt_ops[~filt].for_refcnt = 0; 950 } 951 mtx_unlock(&filterops_lock); 952 953 return error; 954 } 955 956 static struct filterops * 957 kqueue_fo_find(int filt) 958 { 959 960 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 961 return NULL; 962 963 mtx_lock(&filterops_lock); 964 sysfilt_ops[~filt].for_refcnt++; 965 if (sysfilt_ops[~filt].for_fop == NULL) 966 sysfilt_ops[~filt].for_fop = &null_filtops; 967 mtx_unlock(&filterops_lock); 968 969 return sysfilt_ops[~filt].for_fop; 970 } 971 972 static void 973 kqueue_fo_release(int filt) 974 { 975 976 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 977 return; 978 979 mtx_lock(&filterops_lock); 980 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 981 ("filter object refcount not valid on release")); 982 sysfilt_ops[~filt].for_refcnt--; 983 mtx_unlock(&filterops_lock); 984 } 985 986 /* 987 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 988 * influence if memory allocation should wait. Make sure it is 0 if you 989 * hold any mutexes. 990 */ 991 static int 992 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 993 { 994 struct filterops *fops; 995 struct file *fp; 996 struct knote *kn, *tkn; 997 cap_rights_t rights; 998 int error, filt, event; 999 int haskqglobal, filedesc_unlock; 1000 1001 fp = NULL; 1002 kn = NULL; 1003 error = 0; 1004 haskqglobal = 0; 1005 filedesc_unlock = 0; 1006 1007 filt = kev->filter; 1008 fops = kqueue_fo_find(filt); 1009 if (fops == NULL) 1010 return EINVAL; 1011 1012 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1013 1014 findkn: 1015 if (fops->f_isfd) { 1016 KASSERT(td != NULL, ("td is NULL")); 1017 error = fget(td, kev->ident, 1018 cap_rights_init(&rights, CAP_POLL_EVENT), &fp); 1019 if (error) 1020 goto done; 1021 1022 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1023 kev->ident, 0) != 0) { 1024 /* try again */ 1025 fdrop(fp, td); 1026 fp = NULL; 1027 error = kqueue_expand(kq, fops, kev->ident, waitok); 1028 if (error) 1029 goto done; 1030 goto findkn; 1031 } 1032 1033 if (fp->f_type == DTYPE_KQUEUE) { 1034 /* 1035 * if we add some inteligence about what we are doing, 1036 * we should be able to support events on ourselves. 1037 * We need to know when we are doing this to prevent 1038 * getting both the knlist lock and the kq lock since 1039 * they are the same thing. 1040 */ 1041 if (fp->f_data == kq) { 1042 error = EINVAL; 1043 goto done; 1044 } 1045 1046 /* 1047 * Pre-lock the filedesc before the global 1048 * lock mutex, see the comment in 1049 * kqueue_close(). 1050 */ 1051 FILEDESC_XLOCK(td->td_proc->p_fd); 1052 filedesc_unlock = 1; 1053 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1054 } 1055 1056 KQ_LOCK(kq); 1057 if (kev->ident < kq->kq_knlistsize) { 1058 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1059 if (kev->filter == kn->kn_filter) 1060 break; 1061 } 1062 } else { 1063 if ((kev->flags & EV_ADD) == EV_ADD) 1064 kqueue_expand(kq, fops, kev->ident, waitok); 1065 1066 KQ_LOCK(kq); 1067 if (kq->kq_knhashmask != 0) { 1068 struct klist *list; 1069 1070 list = &kq->kq_knhash[ 1071 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1072 SLIST_FOREACH(kn, list, kn_link) 1073 if (kev->ident == kn->kn_id && 1074 kev->filter == kn->kn_filter) 1075 break; 1076 } 1077 } 1078 1079 /* knote is in the process of changing, wait for it to stablize. */ 1080 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1081 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1082 if (filedesc_unlock) { 1083 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1084 filedesc_unlock = 0; 1085 } 1086 kq->kq_state |= KQ_FLUXWAIT; 1087 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1088 if (fp != NULL) { 1089 fdrop(fp, td); 1090 fp = NULL; 1091 } 1092 goto findkn; 1093 } 1094 1095 /* 1096 * kn now contains the matching knote, or NULL if no match 1097 */ 1098 if (kn == NULL) { 1099 if (kev->flags & EV_ADD) { 1100 kn = tkn; 1101 tkn = NULL; 1102 if (kn == NULL) { 1103 KQ_UNLOCK(kq); 1104 error = ENOMEM; 1105 goto done; 1106 } 1107 kn->kn_fp = fp; 1108 kn->kn_kq = kq; 1109 kn->kn_fop = fops; 1110 /* 1111 * apply reference counts to knote structure, and 1112 * do not release it at the end of this routine. 1113 */ 1114 fops = NULL; 1115 fp = NULL; 1116 1117 kn->kn_sfflags = kev->fflags; 1118 kn->kn_sdata = kev->data; 1119 kev->fflags = 0; 1120 kev->data = 0; 1121 kn->kn_kevent = *kev; 1122 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1123 EV_ENABLE | EV_DISABLE); 1124 kn->kn_status = KN_INFLUX|KN_DETACHED; 1125 1126 error = knote_attach(kn, kq); 1127 KQ_UNLOCK(kq); 1128 if (error != 0) { 1129 tkn = kn; 1130 goto done; 1131 } 1132 1133 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1134 knote_drop(kn, td); 1135 goto done; 1136 } 1137 KN_LIST_LOCK(kn); 1138 goto done_ev_add; 1139 } else { 1140 /* No matching knote and the EV_ADD flag is not set. */ 1141 KQ_UNLOCK(kq); 1142 error = ENOENT; 1143 goto done; 1144 } 1145 } 1146 1147 if (kev->flags & EV_DELETE) { 1148 kn->kn_status |= KN_INFLUX; 1149 KQ_UNLOCK(kq); 1150 if (!(kn->kn_status & KN_DETACHED)) 1151 kn->kn_fop->f_detach(kn); 1152 knote_drop(kn, td); 1153 goto done; 1154 } 1155 1156 /* 1157 * The user may change some filter values after the initial EV_ADD, 1158 * but doing so will not reset any filter which has already been 1159 * triggered. 1160 */ 1161 kn->kn_status |= KN_INFLUX; 1162 KQ_UNLOCK(kq); 1163 KN_LIST_LOCK(kn); 1164 kn->kn_kevent.udata = kev->udata; 1165 if (!fops->f_isfd && fops->f_touch != NULL) { 1166 fops->f_touch(kn, kev, EVENT_REGISTER); 1167 } else { 1168 kn->kn_sfflags = kev->fflags; 1169 kn->kn_sdata = kev->data; 1170 } 1171 1172 /* 1173 * We can get here with kn->kn_knlist == NULL. This can happen when 1174 * the initial attach event decides that the event is "completed" 1175 * already. i.e. filt_procattach is called on a zombie process. It 1176 * will call filt_proc which will remove it from the list, and NULL 1177 * kn_knlist. 1178 */ 1179 done_ev_add: 1180 event = kn->kn_fop->f_event(kn, 0); 1181 KQ_LOCK(kq); 1182 if (event) 1183 KNOTE_ACTIVATE(kn, 1); 1184 kn->kn_status &= ~KN_INFLUX; 1185 KN_LIST_UNLOCK(kn); 1186 1187 if ((kev->flags & EV_DISABLE) && 1188 ((kn->kn_status & KN_DISABLED) == 0)) { 1189 kn->kn_status |= KN_DISABLED; 1190 } 1191 1192 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1193 kn->kn_status &= ~KN_DISABLED; 1194 if ((kn->kn_status & KN_ACTIVE) && 1195 ((kn->kn_status & KN_QUEUED) == 0)) 1196 knote_enqueue(kn); 1197 } 1198 KQ_UNLOCK_FLUX(kq); 1199 1200 done: 1201 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1202 if (filedesc_unlock) 1203 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1204 if (fp != NULL) 1205 fdrop(fp, td); 1206 if (tkn != NULL) 1207 knote_free(tkn); 1208 if (fops != NULL) 1209 kqueue_fo_release(filt); 1210 return (error); 1211 } 1212 1213 static int 1214 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1215 { 1216 int error; 1217 struct kqueue *kq; 1218 1219 error = 0; 1220 1221 kq = fp->f_data; 1222 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1223 return (EBADF); 1224 *kqp = kq; 1225 KQ_LOCK(kq); 1226 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1227 KQ_UNLOCK(kq); 1228 return (EBADF); 1229 } 1230 kq->kq_refcnt++; 1231 KQ_UNLOCK(kq); 1232 1233 return error; 1234 } 1235 1236 static void 1237 kqueue_release(struct kqueue *kq, int locked) 1238 { 1239 if (locked) 1240 KQ_OWNED(kq); 1241 else 1242 KQ_LOCK(kq); 1243 kq->kq_refcnt--; 1244 if (kq->kq_refcnt == 1) 1245 wakeup(&kq->kq_refcnt); 1246 if (!locked) 1247 KQ_UNLOCK(kq); 1248 } 1249 1250 static void 1251 kqueue_schedtask(struct kqueue *kq) 1252 { 1253 1254 KQ_OWNED(kq); 1255 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1256 ("scheduling kqueue task while draining")); 1257 1258 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1259 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1260 kq->kq_state |= KQ_TASKSCHED; 1261 } 1262 } 1263 1264 /* 1265 * Expand the kq to make sure we have storage for fops/ident pair. 1266 * 1267 * Return 0 on success (or no work necessary), return errno on failure. 1268 * 1269 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1270 * If kqueue_register is called from a non-fd context, there usually/should 1271 * be no locks held. 1272 */ 1273 static int 1274 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1275 int waitok) 1276 { 1277 struct klist *list, *tmp_knhash, *to_free; 1278 u_long tmp_knhashmask; 1279 int size; 1280 int fd; 1281 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1282 1283 KQ_NOTOWNED(kq); 1284 1285 to_free = NULL; 1286 if (fops->f_isfd) { 1287 fd = ident; 1288 if (kq->kq_knlistsize <= fd) { 1289 size = kq->kq_knlistsize; 1290 while (size <= fd) 1291 size += KQEXTENT; 1292 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1293 if (list == NULL) 1294 return ENOMEM; 1295 KQ_LOCK(kq); 1296 if (kq->kq_knlistsize > fd) { 1297 to_free = list; 1298 list = NULL; 1299 } else { 1300 if (kq->kq_knlist != NULL) { 1301 bcopy(kq->kq_knlist, list, 1302 kq->kq_knlistsize * sizeof(*list)); 1303 to_free = kq->kq_knlist; 1304 kq->kq_knlist = NULL; 1305 } 1306 bzero((caddr_t)list + 1307 kq->kq_knlistsize * sizeof(*list), 1308 (size - kq->kq_knlistsize) * sizeof(*list)); 1309 kq->kq_knlistsize = size; 1310 kq->kq_knlist = list; 1311 } 1312 KQ_UNLOCK(kq); 1313 } 1314 } else { 1315 if (kq->kq_knhashmask == 0) { 1316 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1317 &tmp_knhashmask); 1318 if (tmp_knhash == NULL) 1319 return ENOMEM; 1320 KQ_LOCK(kq); 1321 if (kq->kq_knhashmask == 0) { 1322 kq->kq_knhash = tmp_knhash; 1323 kq->kq_knhashmask = tmp_knhashmask; 1324 } else { 1325 to_free = tmp_knhash; 1326 } 1327 KQ_UNLOCK(kq); 1328 } 1329 } 1330 free(to_free, M_KQUEUE); 1331 1332 KQ_NOTOWNED(kq); 1333 return 0; 1334 } 1335 1336 static void 1337 kqueue_task(void *arg, int pending) 1338 { 1339 struct kqueue *kq; 1340 int haskqglobal; 1341 1342 haskqglobal = 0; 1343 kq = arg; 1344 1345 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1346 KQ_LOCK(kq); 1347 1348 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1349 1350 kq->kq_state &= ~KQ_TASKSCHED; 1351 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1352 wakeup(&kq->kq_state); 1353 } 1354 KQ_UNLOCK(kq); 1355 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1356 } 1357 1358 /* 1359 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1360 * We treat KN_MARKER knotes as if they are INFLUX. 1361 */ 1362 static int 1363 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1364 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1365 { 1366 struct kevent *kevp; 1367 struct knote *kn, *marker; 1368 sbintime_t asbt, rsbt; 1369 int count, error, haskqglobal, influx, nkev, touch; 1370 1371 count = maxevents; 1372 nkev = 0; 1373 error = 0; 1374 haskqglobal = 0; 1375 1376 if (maxevents == 0) 1377 goto done_nl; 1378 1379 rsbt = 0; 1380 if (tsp != NULL) { 1381 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1382 tsp->tv_nsec >= 1000000000) { 1383 error = EINVAL; 1384 goto done_nl; 1385 } 1386 if (timespecisset(tsp)) { 1387 if (tsp->tv_sec <= INT32_MAX) { 1388 rsbt = tstosbt(*tsp); 1389 if (TIMESEL(&asbt, rsbt)) 1390 asbt += tc_tick_sbt; 1391 if (asbt <= INT64_MAX - rsbt) 1392 asbt += rsbt; 1393 else 1394 asbt = 0; 1395 rsbt >>= tc_precexp; 1396 } else 1397 asbt = 0; 1398 } else 1399 asbt = -1; 1400 } else 1401 asbt = 0; 1402 marker = knote_alloc(1); 1403 if (marker == NULL) { 1404 error = ENOMEM; 1405 goto done_nl; 1406 } 1407 marker->kn_status = KN_MARKER; 1408 KQ_LOCK(kq); 1409 1410 retry: 1411 kevp = keva; 1412 if (kq->kq_count == 0) { 1413 if (asbt == -1) { 1414 error = EWOULDBLOCK; 1415 } else { 1416 kq->kq_state |= KQ_SLEEP; 1417 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1418 "kqread", asbt, rsbt, C_ABSOLUTE); 1419 } 1420 if (error == 0) 1421 goto retry; 1422 /* don't restart after signals... */ 1423 if (error == ERESTART) 1424 error = EINTR; 1425 else if (error == EWOULDBLOCK) 1426 error = 0; 1427 goto done; 1428 } 1429 1430 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1431 influx = 0; 1432 while (count) { 1433 KQ_OWNED(kq); 1434 kn = TAILQ_FIRST(&kq->kq_head); 1435 1436 if ((kn->kn_status == KN_MARKER && kn != marker) || 1437 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1438 if (influx) { 1439 influx = 0; 1440 KQ_FLUX_WAKEUP(kq); 1441 } 1442 kq->kq_state |= KQ_FLUXWAIT; 1443 error = msleep(kq, &kq->kq_lock, PSOCK, 1444 "kqflxwt", 0); 1445 continue; 1446 } 1447 1448 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1449 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1450 kn->kn_status &= ~KN_QUEUED; 1451 kq->kq_count--; 1452 continue; 1453 } 1454 if (kn == marker) { 1455 KQ_FLUX_WAKEUP(kq); 1456 if (count == maxevents) 1457 goto retry; 1458 goto done; 1459 } 1460 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1461 ("KN_INFLUX set when not suppose to be")); 1462 1463 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1464 kn->kn_status &= ~KN_QUEUED; 1465 kn->kn_status |= KN_INFLUX; 1466 kq->kq_count--; 1467 KQ_UNLOCK(kq); 1468 /* 1469 * We don't need to lock the list since we've marked 1470 * it _INFLUX. 1471 */ 1472 if (!(kn->kn_status & KN_DETACHED)) 1473 kn->kn_fop->f_detach(kn); 1474 knote_drop(kn, td); 1475 KQ_LOCK(kq); 1476 continue; 1477 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1478 kn->kn_status &= ~KN_QUEUED; 1479 kn->kn_status |= KN_INFLUX; 1480 kq->kq_count--; 1481 KQ_UNLOCK(kq); 1482 /* 1483 * We don't need to lock the list since we've marked 1484 * it _INFLUX. 1485 */ 1486 *kevp = kn->kn_kevent; 1487 if (!(kn->kn_status & KN_DETACHED)) 1488 kn->kn_fop->f_detach(kn); 1489 knote_drop(kn, td); 1490 KQ_LOCK(kq); 1491 kn = NULL; 1492 } else { 1493 kn->kn_status |= KN_INFLUX; 1494 KQ_UNLOCK(kq); 1495 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1496 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1497 KN_LIST_LOCK(kn); 1498 if (kn->kn_fop->f_event(kn, 0) == 0) { 1499 KQ_LOCK(kq); 1500 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1501 kn->kn_status &= 1502 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX); 1503 kq->kq_count--; 1504 KN_LIST_UNLOCK(kn); 1505 influx = 1; 1506 continue; 1507 } 1508 touch = (!kn->kn_fop->f_isfd && 1509 kn->kn_fop->f_touch != NULL); 1510 if (touch) 1511 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1512 else 1513 *kevp = kn->kn_kevent; 1514 KQ_LOCK(kq); 1515 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1516 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1517 /* 1518 * Manually clear knotes who weren't 1519 * 'touch'ed. 1520 */ 1521 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1522 kn->kn_data = 0; 1523 kn->kn_fflags = 0; 1524 } 1525 if (kn->kn_flags & EV_DISPATCH) 1526 kn->kn_status |= KN_DISABLED; 1527 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1528 kq->kq_count--; 1529 } else 1530 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1531 1532 kn->kn_status &= ~(KN_INFLUX); 1533 KN_LIST_UNLOCK(kn); 1534 influx = 1; 1535 } 1536 1537 /* we are returning a copy to the user */ 1538 kevp++; 1539 nkev++; 1540 count--; 1541 1542 if (nkev == KQ_NEVENTS) { 1543 influx = 0; 1544 KQ_UNLOCK_FLUX(kq); 1545 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1546 nkev = 0; 1547 kevp = keva; 1548 KQ_LOCK(kq); 1549 if (error) 1550 break; 1551 } 1552 } 1553 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1554 done: 1555 KQ_OWNED(kq); 1556 KQ_UNLOCK_FLUX(kq); 1557 knote_free(marker); 1558 done_nl: 1559 KQ_NOTOWNED(kq); 1560 if (nkev != 0) 1561 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1562 td->td_retval[0] = maxevents - count; 1563 return (error); 1564 } 1565 1566 /* 1567 * XXX 1568 * This could be expanded to call kqueue_scan, if desired. 1569 */ 1570 /*ARGSUSED*/ 1571 static int 1572 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1573 int flags, struct thread *td) 1574 { 1575 return (ENXIO); 1576 } 1577 1578 /*ARGSUSED*/ 1579 static int 1580 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1581 int flags, struct thread *td) 1582 { 1583 return (ENXIO); 1584 } 1585 1586 /*ARGSUSED*/ 1587 static int 1588 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1589 struct thread *td) 1590 { 1591 1592 return (EINVAL); 1593 } 1594 1595 /*ARGSUSED*/ 1596 static int 1597 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1598 struct ucred *active_cred, struct thread *td) 1599 { 1600 /* 1601 * Enabling sigio causes two major problems: 1602 * 1) infinite recursion: 1603 * Synopsys: kevent is being used to track signals and have FIOASYNC 1604 * set. On receipt of a signal this will cause a kqueue to recurse 1605 * into itself over and over. Sending the sigio causes the kqueue 1606 * to become ready, which in turn posts sigio again, forever. 1607 * Solution: this can be solved by setting a flag in the kqueue that 1608 * we have a SIGIO in progress. 1609 * 2) locking problems: 1610 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1611 * us above the proc and pgrp locks. 1612 * Solution: Post a signal using an async mechanism, being sure to 1613 * record a generation count in the delivery so that we do not deliver 1614 * a signal to the wrong process. 1615 * 1616 * Note, these two mechanisms are somewhat mutually exclusive! 1617 */ 1618 #if 0 1619 struct kqueue *kq; 1620 1621 kq = fp->f_data; 1622 switch (cmd) { 1623 case FIOASYNC: 1624 if (*(int *)data) { 1625 kq->kq_state |= KQ_ASYNC; 1626 } else { 1627 kq->kq_state &= ~KQ_ASYNC; 1628 } 1629 return (0); 1630 1631 case FIOSETOWN: 1632 return (fsetown(*(int *)data, &kq->kq_sigio)); 1633 1634 case FIOGETOWN: 1635 *(int *)data = fgetown(&kq->kq_sigio); 1636 return (0); 1637 } 1638 #endif 1639 1640 return (ENOTTY); 1641 } 1642 1643 /*ARGSUSED*/ 1644 static int 1645 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1646 struct thread *td) 1647 { 1648 struct kqueue *kq; 1649 int revents = 0; 1650 int error; 1651 1652 if ((error = kqueue_acquire(fp, &kq))) 1653 return POLLERR; 1654 1655 KQ_LOCK(kq); 1656 if (events & (POLLIN | POLLRDNORM)) { 1657 if (kq->kq_count) { 1658 revents |= events & (POLLIN | POLLRDNORM); 1659 } else { 1660 selrecord(td, &kq->kq_sel); 1661 if (SEL_WAITING(&kq->kq_sel)) 1662 kq->kq_state |= KQ_SEL; 1663 } 1664 } 1665 kqueue_release(kq, 1); 1666 KQ_UNLOCK(kq); 1667 return (revents); 1668 } 1669 1670 /*ARGSUSED*/ 1671 static int 1672 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1673 struct thread *td) 1674 { 1675 1676 bzero((void *)st, sizeof *st); 1677 /* 1678 * We no longer return kq_count because the unlocked value is useless. 1679 * If you spent all this time getting the count, why not spend your 1680 * syscall better by calling kevent? 1681 * 1682 * XXX - This is needed for libc_r. 1683 */ 1684 st->st_mode = S_IFIFO; 1685 return (0); 1686 } 1687 1688 /*ARGSUSED*/ 1689 static int 1690 kqueue_close(struct file *fp, struct thread *td) 1691 { 1692 struct kqueue *kq = fp->f_data; 1693 struct filedesc *fdp; 1694 struct knote *kn; 1695 int i; 1696 int error; 1697 int filedesc_unlock; 1698 1699 if ((error = kqueue_acquire(fp, &kq))) 1700 return error; 1701 1702 filedesc_unlock = 0; 1703 KQ_LOCK(kq); 1704 1705 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1706 ("kqueue already closing")); 1707 kq->kq_state |= KQ_CLOSING; 1708 if (kq->kq_refcnt > 1) 1709 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1710 1711 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1712 fdp = kq->kq_fdp; 1713 1714 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1715 ("kqueue's knlist not empty")); 1716 1717 for (i = 0; i < kq->kq_knlistsize; i++) { 1718 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1719 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1720 kq->kq_state |= KQ_FLUXWAIT; 1721 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1722 continue; 1723 } 1724 kn->kn_status |= KN_INFLUX; 1725 KQ_UNLOCK(kq); 1726 if (!(kn->kn_status & KN_DETACHED)) 1727 kn->kn_fop->f_detach(kn); 1728 knote_drop(kn, td); 1729 KQ_LOCK(kq); 1730 } 1731 } 1732 if (kq->kq_knhashmask != 0) { 1733 for (i = 0; i <= kq->kq_knhashmask; i++) { 1734 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1735 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1736 kq->kq_state |= KQ_FLUXWAIT; 1737 msleep(kq, &kq->kq_lock, PSOCK, 1738 "kqclo2", 0); 1739 continue; 1740 } 1741 kn->kn_status |= KN_INFLUX; 1742 KQ_UNLOCK(kq); 1743 if (!(kn->kn_status & KN_DETACHED)) 1744 kn->kn_fop->f_detach(kn); 1745 knote_drop(kn, td); 1746 KQ_LOCK(kq); 1747 } 1748 } 1749 } 1750 1751 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1752 kq->kq_state |= KQ_TASKDRAIN; 1753 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1754 } 1755 1756 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1757 selwakeuppri(&kq->kq_sel, PSOCK); 1758 if (!SEL_WAITING(&kq->kq_sel)) 1759 kq->kq_state &= ~KQ_SEL; 1760 } 1761 1762 KQ_UNLOCK(kq); 1763 1764 /* 1765 * We could be called due to the knote_drop() doing fdrop(), 1766 * called from kqueue_register(). In this case the global 1767 * lock is owned, and filedesc sx is locked before, to not 1768 * take the sleepable lock after non-sleepable. 1769 */ 1770 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1771 FILEDESC_XLOCK(fdp); 1772 filedesc_unlock = 1; 1773 } else 1774 filedesc_unlock = 0; 1775 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1776 if (filedesc_unlock) 1777 FILEDESC_XUNLOCK(fdp); 1778 1779 seldrain(&kq->kq_sel); 1780 knlist_destroy(&kq->kq_sel.si_note); 1781 mtx_destroy(&kq->kq_lock); 1782 kq->kq_fdp = NULL; 1783 1784 if (kq->kq_knhash != NULL) 1785 free(kq->kq_knhash, M_KQUEUE); 1786 if (kq->kq_knlist != NULL) 1787 free(kq->kq_knlist, M_KQUEUE); 1788 1789 funsetown(&kq->kq_sigio); 1790 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 1791 crfree(kq->kq_cred); 1792 free(kq, M_KQUEUE); 1793 fp->f_data = NULL; 1794 1795 return (0); 1796 } 1797 1798 static void 1799 kqueue_wakeup(struct kqueue *kq) 1800 { 1801 KQ_OWNED(kq); 1802 1803 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1804 kq->kq_state &= ~KQ_SLEEP; 1805 wakeup(kq); 1806 } 1807 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1808 selwakeuppri(&kq->kq_sel, PSOCK); 1809 if (!SEL_WAITING(&kq->kq_sel)) 1810 kq->kq_state &= ~KQ_SEL; 1811 } 1812 if (!knlist_empty(&kq->kq_sel.si_note)) 1813 kqueue_schedtask(kq); 1814 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1815 pgsigio(&kq->kq_sigio, SIGIO, 0); 1816 } 1817 } 1818 1819 /* 1820 * Walk down a list of knotes, activating them if their event has triggered. 1821 * 1822 * There is a possibility to optimize in the case of one kq watching another. 1823 * Instead of scheduling a task to wake it up, you could pass enough state 1824 * down the chain to make up the parent kqueue. Make this code functional 1825 * first. 1826 */ 1827 void 1828 knote(struct knlist *list, long hint, int lockflags) 1829 { 1830 struct kqueue *kq; 1831 struct knote *kn; 1832 int error; 1833 1834 if (list == NULL) 1835 return; 1836 1837 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1838 1839 if ((lockflags & KNF_LISTLOCKED) == 0) 1840 list->kl_lock(list->kl_lockarg); 1841 1842 /* 1843 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1844 * the kqueue scheduling, but this will introduce four 1845 * lock/unlock's for each knote to test. If we do, continue to use 1846 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1847 * only safe if you want to remove the current item, which we are 1848 * not doing. 1849 */ 1850 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1851 kq = kn->kn_kq; 1852 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { 1853 KQ_LOCK(kq); 1854 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1855 KQ_UNLOCK(kq); 1856 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1857 kn->kn_status |= KN_INFLUX; 1858 KQ_UNLOCK(kq); 1859 error = kn->kn_fop->f_event(kn, hint); 1860 KQ_LOCK(kq); 1861 kn->kn_status &= ~KN_INFLUX; 1862 if (error) 1863 KNOTE_ACTIVATE(kn, 1); 1864 KQ_UNLOCK_FLUX(kq); 1865 } else { 1866 kn->kn_status |= KN_HASKQLOCK; 1867 if (kn->kn_fop->f_event(kn, hint)) 1868 KNOTE_ACTIVATE(kn, 1); 1869 kn->kn_status &= ~KN_HASKQLOCK; 1870 KQ_UNLOCK(kq); 1871 } 1872 } 1873 kq = NULL; 1874 } 1875 if ((lockflags & KNF_LISTLOCKED) == 0) 1876 list->kl_unlock(list->kl_lockarg); 1877 } 1878 1879 /* 1880 * add a knote to a knlist 1881 */ 1882 void 1883 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1884 { 1885 KNL_ASSERT_LOCK(knl, islocked); 1886 KQ_NOTOWNED(kn->kn_kq); 1887 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1888 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1889 if (!islocked) 1890 knl->kl_lock(knl->kl_lockarg); 1891 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1892 if (!islocked) 1893 knl->kl_unlock(knl->kl_lockarg); 1894 KQ_LOCK(kn->kn_kq); 1895 kn->kn_knlist = knl; 1896 kn->kn_status &= ~KN_DETACHED; 1897 KQ_UNLOCK(kn->kn_kq); 1898 } 1899 1900 static void 1901 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1902 { 1903 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1904 KNL_ASSERT_LOCK(knl, knlislocked); 1905 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1906 if (!kqislocked) 1907 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1908 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1909 if (!knlislocked) 1910 knl->kl_lock(knl->kl_lockarg); 1911 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1912 kn->kn_knlist = NULL; 1913 if (!knlislocked) 1914 knl->kl_unlock(knl->kl_lockarg); 1915 if (!kqislocked) 1916 KQ_LOCK(kn->kn_kq); 1917 kn->kn_status |= KN_DETACHED; 1918 if (!kqislocked) 1919 KQ_UNLOCK(kn->kn_kq); 1920 } 1921 1922 /* 1923 * remove knote from the specified knlist 1924 */ 1925 void 1926 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1927 { 1928 1929 knlist_remove_kq(knl, kn, islocked, 0); 1930 } 1931 1932 /* 1933 * remove knote from the specified knlist while in f_event handler. 1934 */ 1935 void 1936 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1937 { 1938 1939 knlist_remove_kq(knl, kn, 1, 1940 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1941 } 1942 1943 int 1944 knlist_empty(struct knlist *knl) 1945 { 1946 1947 KNL_ASSERT_LOCKED(knl); 1948 return SLIST_EMPTY(&knl->kl_list); 1949 } 1950 1951 static struct mtx knlist_lock; 1952 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1953 MTX_DEF); 1954 static void knlist_mtx_lock(void *arg); 1955 static void knlist_mtx_unlock(void *arg); 1956 1957 static void 1958 knlist_mtx_lock(void *arg) 1959 { 1960 1961 mtx_lock((struct mtx *)arg); 1962 } 1963 1964 static void 1965 knlist_mtx_unlock(void *arg) 1966 { 1967 1968 mtx_unlock((struct mtx *)arg); 1969 } 1970 1971 static void 1972 knlist_mtx_assert_locked(void *arg) 1973 { 1974 1975 mtx_assert((struct mtx *)arg, MA_OWNED); 1976 } 1977 1978 static void 1979 knlist_mtx_assert_unlocked(void *arg) 1980 { 1981 1982 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 1983 } 1984 1985 static void 1986 knlist_rw_rlock(void *arg) 1987 { 1988 1989 rw_rlock((struct rwlock *)arg); 1990 } 1991 1992 static void 1993 knlist_rw_runlock(void *arg) 1994 { 1995 1996 rw_runlock((struct rwlock *)arg); 1997 } 1998 1999 static void 2000 knlist_rw_assert_locked(void *arg) 2001 { 2002 2003 rw_assert((struct rwlock *)arg, RA_LOCKED); 2004 } 2005 2006 static void 2007 knlist_rw_assert_unlocked(void *arg) 2008 { 2009 2010 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2011 } 2012 2013 void 2014 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2015 void (*kl_unlock)(void *), 2016 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2017 { 2018 2019 if (lock == NULL) 2020 knl->kl_lockarg = &knlist_lock; 2021 else 2022 knl->kl_lockarg = lock; 2023 2024 if (kl_lock == NULL) 2025 knl->kl_lock = knlist_mtx_lock; 2026 else 2027 knl->kl_lock = kl_lock; 2028 if (kl_unlock == NULL) 2029 knl->kl_unlock = knlist_mtx_unlock; 2030 else 2031 knl->kl_unlock = kl_unlock; 2032 if (kl_assert_locked == NULL) 2033 knl->kl_assert_locked = knlist_mtx_assert_locked; 2034 else 2035 knl->kl_assert_locked = kl_assert_locked; 2036 if (kl_assert_unlocked == NULL) 2037 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2038 else 2039 knl->kl_assert_unlocked = kl_assert_unlocked; 2040 2041 SLIST_INIT(&knl->kl_list); 2042 } 2043 2044 void 2045 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2046 { 2047 2048 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2049 } 2050 2051 void 2052 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2053 { 2054 2055 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2056 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2057 } 2058 2059 void 2060 knlist_destroy(struct knlist *knl) 2061 { 2062 2063 #ifdef INVARIANTS 2064 /* 2065 * if we run across this error, we need to find the offending 2066 * driver and have it call knlist_clear or knlist_delete. 2067 */ 2068 if (!SLIST_EMPTY(&knl->kl_list)) 2069 printf("WARNING: destroying knlist w/ knotes on it!\n"); 2070 #endif 2071 2072 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 2073 SLIST_INIT(&knl->kl_list); 2074 } 2075 2076 /* 2077 * Even if we are locked, we may need to drop the lock to allow any influx 2078 * knotes time to "settle". 2079 */ 2080 void 2081 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2082 { 2083 struct knote *kn, *kn2; 2084 struct kqueue *kq; 2085 2086 if (islocked) 2087 KNL_ASSERT_LOCKED(knl); 2088 else { 2089 KNL_ASSERT_UNLOCKED(knl); 2090 again: /* need to reacquire lock since we have dropped it */ 2091 knl->kl_lock(knl->kl_lockarg); 2092 } 2093 2094 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2095 kq = kn->kn_kq; 2096 KQ_LOCK(kq); 2097 if ((kn->kn_status & KN_INFLUX)) { 2098 KQ_UNLOCK(kq); 2099 continue; 2100 } 2101 knlist_remove_kq(knl, kn, 1, 1); 2102 if (killkn) { 2103 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2104 KQ_UNLOCK(kq); 2105 knote_drop(kn, td); 2106 } else { 2107 /* Make sure cleared knotes disappear soon */ 2108 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2109 KQ_UNLOCK(kq); 2110 } 2111 kq = NULL; 2112 } 2113 2114 if (!SLIST_EMPTY(&knl->kl_list)) { 2115 /* there are still KN_INFLUX remaining */ 2116 kn = SLIST_FIRST(&knl->kl_list); 2117 kq = kn->kn_kq; 2118 KQ_LOCK(kq); 2119 KASSERT(kn->kn_status & KN_INFLUX, 2120 ("knote removed w/o list lock")); 2121 knl->kl_unlock(knl->kl_lockarg); 2122 kq->kq_state |= KQ_FLUXWAIT; 2123 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2124 kq = NULL; 2125 goto again; 2126 } 2127 2128 if (islocked) 2129 KNL_ASSERT_LOCKED(knl); 2130 else { 2131 knl->kl_unlock(knl->kl_lockarg); 2132 KNL_ASSERT_UNLOCKED(knl); 2133 } 2134 } 2135 2136 /* 2137 * Remove all knotes referencing a specified fd must be called with FILEDESC 2138 * lock. This prevents a race where a new fd comes along and occupies the 2139 * entry and we attach a knote to the fd. 2140 */ 2141 void 2142 knote_fdclose(struct thread *td, int fd) 2143 { 2144 struct filedesc *fdp = td->td_proc->p_fd; 2145 struct kqueue *kq; 2146 struct knote *kn; 2147 int influx; 2148 2149 FILEDESC_XLOCK_ASSERT(fdp); 2150 2151 /* 2152 * We shouldn't have to worry about new kevents appearing on fd 2153 * since filedesc is locked. 2154 */ 2155 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2156 KQ_LOCK(kq); 2157 2158 again: 2159 influx = 0; 2160 while (kq->kq_knlistsize > fd && 2161 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2162 if (kn->kn_status & KN_INFLUX) { 2163 /* someone else might be waiting on our knote */ 2164 if (influx) 2165 wakeup(kq); 2166 kq->kq_state |= KQ_FLUXWAIT; 2167 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2168 goto again; 2169 } 2170 kn->kn_status |= KN_INFLUX; 2171 KQ_UNLOCK(kq); 2172 if (!(kn->kn_status & KN_DETACHED)) 2173 kn->kn_fop->f_detach(kn); 2174 knote_drop(kn, td); 2175 influx = 1; 2176 KQ_LOCK(kq); 2177 } 2178 KQ_UNLOCK_FLUX(kq); 2179 } 2180 } 2181 2182 static int 2183 knote_attach(struct knote *kn, struct kqueue *kq) 2184 { 2185 struct klist *list; 2186 2187 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2188 KQ_OWNED(kq); 2189 2190 if (kn->kn_fop->f_isfd) { 2191 if (kn->kn_id >= kq->kq_knlistsize) 2192 return ENOMEM; 2193 list = &kq->kq_knlist[kn->kn_id]; 2194 } else { 2195 if (kq->kq_knhash == NULL) 2196 return ENOMEM; 2197 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2198 } 2199 2200 SLIST_INSERT_HEAD(list, kn, kn_link); 2201 2202 return 0; 2203 } 2204 2205 /* 2206 * knote must already have been detached using the f_detach method. 2207 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2208 * to prevent other removal. 2209 */ 2210 static void 2211 knote_drop(struct knote *kn, struct thread *td) 2212 { 2213 struct kqueue *kq; 2214 struct klist *list; 2215 2216 kq = kn->kn_kq; 2217 2218 KQ_NOTOWNED(kq); 2219 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2220 ("knote_drop called without KN_INFLUX set in kn_status")); 2221 2222 KQ_LOCK(kq); 2223 if (kn->kn_fop->f_isfd) 2224 list = &kq->kq_knlist[kn->kn_id]; 2225 else 2226 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2227 2228 if (!SLIST_EMPTY(list)) 2229 SLIST_REMOVE(list, kn, knote, kn_link); 2230 if (kn->kn_status & KN_QUEUED) 2231 knote_dequeue(kn); 2232 KQ_UNLOCK_FLUX(kq); 2233 2234 if (kn->kn_fop->f_isfd) { 2235 fdrop(kn->kn_fp, td); 2236 kn->kn_fp = NULL; 2237 } 2238 kqueue_fo_release(kn->kn_kevent.filter); 2239 kn->kn_fop = NULL; 2240 knote_free(kn); 2241 } 2242 2243 static void 2244 knote_enqueue(struct knote *kn) 2245 { 2246 struct kqueue *kq = kn->kn_kq; 2247 2248 KQ_OWNED(kn->kn_kq); 2249 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2250 2251 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2252 kn->kn_status |= KN_QUEUED; 2253 kq->kq_count++; 2254 kqueue_wakeup(kq); 2255 } 2256 2257 static void 2258 knote_dequeue(struct knote *kn) 2259 { 2260 struct kqueue *kq = kn->kn_kq; 2261 2262 KQ_OWNED(kn->kn_kq); 2263 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2264 2265 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2266 kn->kn_status &= ~KN_QUEUED; 2267 kq->kq_count--; 2268 } 2269 2270 static void 2271 knote_init(void) 2272 { 2273 2274 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2275 NULL, NULL, UMA_ALIGN_PTR, 0); 2276 } 2277 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2278 2279 static struct knote * 2280 knote_alloc(int waitok) 2281 { 2282 return ((struct knote *)uma_zalloc(knote_zone, 2283 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2284 } 2285 2286 static void 2287 knote_free(struct knote *kn) 2288 { 2289 if (kn != NULL) 2290 uma_zfree(knote_zone, kn); 2291 } 2292 2293 /* 2294 * Register the kev w/ the kq specified by fd. 2295 */ 2296 int 2297 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2298 { 2299 struct kqueue *kq; 2300 struct file *fp; 2301 cap_rights_t rights; 2302 int error; 2303 2304 error = fget(td, fd, cap_rights_init(&rights, CAP_POST_EVENT), &fp); 2305 if (error != 0) 2306 return (error); 2307 if ((error = kqueue_acquire(fp, &kq)) != 0) 2308 goto noacquire; 2309 2310 error = kqueue_register(kq, kev, td, waitok); 2311 2312 kqueue_release(kq, 0); 2313 2314 noacquire: 2315 fdrop(fp, td); 2316 2317 return error; 2318 } 2319