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 #include "opt_kqueue.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/capability.h> 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/mutex.h> 41 #include <sys/rwlock.h> 42 #include <sys/proc.h> 43 #include <sys/malloc.h> 44 #include <sys/unistd.h> 45 #include <sys/file.h> 46 #include <sys/filedesc.h> 47 #include <sys/filio.h> 48 #include <sys/fcntl.h> 49 #include <sys/kthread.h> 50 #include <sys/selinfo.h> 51 #include <sys/stdatomic.h> 52 #include <sys/queue.h> 53 #include <sys/event.h> 54 #include <sys/eventvar.h> 55 #include <sys/poll.h> 56 #include <sys/protosw.h> 57 #include <sys/resourcevar.h> 58 #include <sys/sigio.h> 59 #include <sys/signalvar.h> 60 #include <sys/socket.h> 61 #include <sys/socketvar.h> 62 #include <sys/stat.h> 63 #include <sys/sysctl.h> 64 #include <sys/sysproto.h> 65 #include <sys/syscallsubr.h> 66 #include <sys/taskqueue.h> 67 #include <sys/uio.h> 68 #ifdef KTRACE 69 #include <sys/ktrace.h> 70 #endif 71 72 #include <vm/uma.h> 73 74 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 75 76 /* 77 * This lock is used if multiple kq locks are required. This possibly 78 * should be made into a per proc lock. 79 */ 80 static struct mtx kq_global; 81 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 82 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 83 if (!haslck) \ 84 mtx_lock(lck); \ 85 haslck = 1; \ 86 } while (0) 87 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 88 if (haslck) \ 89 mtx_unlock(lck); \ 90 haslck = 0; \ 91 } while (0) 92 93 TASKQUEUE_DEFINE_THREAD(kqueue); 94 95 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 96 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 97 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 98 struct thread *td, int waitok); 99 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 100 static void kqueue_release(struct kqueue *kq, int locked); 101 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 102 uintptr_t ident, int waitok); 103 static void kqueue_task(void *arg, int pending); 104 static int kqueue_scan(struct kqueue *kq, int maxevents, 105 struct kevent_copyops *k_ops, 106 const struct timespec *timeout, 107 struct kevent *keva, struct thread *td); 108 static void kqueue_wakeup(struct kqueue *kq); 109 static struct filterops *kqueue_fo_find(int filt); 110 static void kqueue_fo_release(int filt); 111 112 static fo_rdwr_t kqueue_read; 113 static fo_rdwr_t kqueue_write; 114 static fo_truncate_t kqueue_truncate; 115 static fo_ioctl_t kqueue_ioctl; 116 static fo_poll_t kqueue_poll; 117 static fo_kqfilter_t kqueue_kqfilter; 118 static fo_stat_t kqueue_stat; 119 static fo_close_t kqueue_close; 120 121 static struct fileops kqueueops = { 122 .fo_read = kqueue_read, 123 .fo_write = kqueue_write, 124 .fo_truncate = kqueue_truncate, 125 .fo_ioctl = kqueue_ioctl, 126 .fo_poll = kqueue_poll, 127 .fo_kqfilter = kqueue_kqfilter, 128 .fo_stat = kqueue_stat, 129 .fo_close = kqueue_close, 130 .fo_chmod = invfo_chmod, 131 .fo_chown = invfo_chown, 132 .fo_sendfile = invfo_sendfile, 133 }; 134 135 static int knote_attach(struct knote *kn, struct kqueue *kq); 136 static void knote_drop(struct knote *kn, struct thread *td); 137 static void knote_enqueue(struct knote *kn); 138 static void knote_dequeue(struct knote *kn); 139 static void knote_init(void); 140 static struct knote *knote_alloc(int waitok); 141 static void knote_free(struct knote *kn); 142 143 static void filt_kqdetach(struct knote *kn); 144 static int filt_kqueue(struct knote *kn, long hint); 145 static int filt_procattach(struct knote *kn); 146 static void filt_procdetach(struct knote *kn); 147 static int filt_proc(struct knote *kn, long hint); 148 static int filt_fileattach(struct knote *kn); 149 static void filt_timerexpire(void *knx); 150 static int filt_timerattach(struct knote *kn); 151 static void filt_timerdetach(struct knote *kn); 152 static int filt_timer(struct knote *kn, long hint); 153 static int filt_userattach(struct knote *kn); 154 static void filt_userdetach(struct knote *kn); 155 static int filt_user(struct knote *kn, long hint); 156 static void filt_usertouch(struct knote *kn, struct kevent *kev, 157 u_long type); 158 159 static struct filterops file_filtops = { 160 .f_isfd = 1, 161 .f_attach = filt_fileattach, 162 }; 163 static struct filterops kqread_filtops = { 164 .f_isfd = 1, 165 .f_detach = filt_kqdetach, 166 .f_event = filt_kqueue, 167 }; 168 /* XXX - move to kern_proc.c? */ 169 static struct filterops proc_filtops = { 170 .f_isfd = 0, 171 .f_attach = filt_procattach, 172 .f_detach = filt_procdetach, 173 .f_event = filt_proc, 174 }; 175 static struct filterops timer_filtops = { 176 .f_isfd = 0, 177 .f_attach = filt_timerattach, 178 .f_detach = filt_timerdetach, 179 .f_event = filt_timer, 180 }; 181 static struct filterops user_filtops = { 182 .f_attach = filt_userattach, 183 .f_detach = filt_userdetach, 184 .f_event = filt_user, 185 .f_touch = filt_usertouch, 186 }; 187 188 static uma_zone_t knote_zone; 189 static atomic_uint kq_ncallouts = ATOMIC_VAR_INIT(0); 190 static unsigned int kq_calloutmax = 4 * 1024; 191 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 192 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 193 194 /* XXX - ensure not KN_INFLUX?? */ 195 #define KNOTE_ACTIVATE(kn, islock) do { \ 196 if ((islock)) \ 197 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 198 else \ 199 KQ_LOCK((kn)->kn_kq); \ 200 (kn)->kn_status |= KN_ACTIVE; \ 201 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 202 knote_enqueue((kn)); \ 203 if (!(islock)) \ 204 KQ_UNLOCK((kn)->kn_kq); \ 205 } while(0) 206 #define KQ_LOCK(kq) do { \ 207 mtx_lock(&(kq)->kq_lock); \ 208 } while (0) 209 #define KQ_FLUX_WAKEUP(kq) do { \ 210 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 211 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 212 wakeup((kq)); \ 213 } \ 214 } while (0) 215 #define KQ_UNLOCK_FLUX(kq) do { \ 216 KQ_FLUX_WAKEUP(kq); \ 217 mtx_unlock(&(kq)->kq_lock); \ 218 } while (0) 219 #define KQ_UNLOCK(kq) do { \ 220 mtx_unlock(&(kq)->kq_lock); \ 221 } while (0) 222 #define KQ_OWNED(kq) do { \ 223 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 224 } while (0) 225 #define KQ_NOTOWNED(kq) do { \ 226 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 227 } while (0) 228 #define KN_LIST_LOCK(kn) do { \ 229 if (kn->kn_knlist != NULL) \ 230 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \ 231 } while (0) 232 #define KN_LIST_UNLOCK(kn) do { \ 233 if (kn->kn_knlist != NULL) \ 234 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \ 235 } while (0) 236 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 237 if (islocked) \ 238 KNL_ASSERT_LOCKED(knl); \ 239 else \ 240 KNL_ASSERT_UNLOCKED(knl); \ 241 } while (0) 242 #ifdef INVARIANTS 243 #define KNL_ASSERT_LOCKED(knl) do { \ 244 knl->kl_assert_locked((knl)->kl_lockarg); \ 245 } while (0) 246 #define KNL_ASSERT_UNLOCKED(knl) do { \ 247 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 248 } while (0) 249 #else /* !INVARIANTS */ 250 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 251 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 252 #endif /* INVARIANTS */ 253 254 #ifndef KN_HASHSIZE 255 #define KN_HASHSIZE 64 /* XXX should be tunable */ 256 #endif 257 258 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 259 260 static int 261 filt_nullattach(struct knote *kn) 262 { 263 264 return (ENXIO); 265 }; 266 267 struct filterops null_filtops = { 268 .f_isfd = 0, 269 .f_attach = filt_nullattach, 270 }; 271 272 /* XXX - make SYSINIT to add these, and move into respective modules. */ 273 extern struct filterops sig_filtops; 274 extern struct filterops fs_filtops; 275 276 /* 277 * Table for for all system-defined filters. 278 */ 279 static struct mtx filterops_lock; 280 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 281 MTX_DEF); 282 static struct { 283 struct filterops *for_fop; 284 int for_refcnt; 285 } sysfilt_ops[EVFILT_SYSCOUNT] = { 286 { &file_filtops }, /* EVFILT_READ */ 287 { &file_filtops }, /* EVFILT_WRITE */ 288 { &null_filtops }, /* EVFILT_AIO */ 289 { &file_filtops }, /* EVFILT_VNODE */ 290 { &proc_filtops }, /* EVFILT_PROC */ 291 { &sig_filtops }, /* EVFILT_SIGNAL */ 292 { &timer_filtops }, /* EVFILT_TIMER */ 293 { &null_filtops }, /* former EVFILT_NETDEV */ 294 { &fs_filtops }, /* EVFILT_FS */ 295 { &null_filtops }, /* EVFILT_LIO */ 296 { &user_filtops }, /* EVFILT_USER */ 297 { &null_filtops }, /* EVFILT_SENDFILE */ 298 }; 299 300 /* 301 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 302 * method. 303 */ 304 static int 305 filt_fileattach(struct knote *kn) 306 { 307 308 return (fo_kqfilter(kn->kn_fp, kn)); 309 } 310 311 /*ARGSUSED*/ 312 static int 313 kqueue_kqfilter(struct file *fp, struct knote *kn) 314 { 315 struct kqueue *kq = kn->kn_fp->f_data; 316 317 if (kn->kn_filter != EVFILT_READ) 318 return (EINVAL); 319 320 kn->kn_status |= KN_KQUEUE; 321 kn->kn_fop = &kqread_filtops; 322 knlist_add(&kq->kq_sel.si_note, kn, 0); 323 324 return (0); 325 } 326 327 static void 328 filt_kqdetach(struct knote *kn) 329 { 330 struct kqueue *kq = kn->kn_fp->f_data; 331 332 knlist_remove(&kq->kq_sel.si_note, kn, 0); 333 } 334 335 /*ARGSUSED*/ 336 static int 337 filt_kqueue(struct knote *kn, long hint) 338 { 339 struct kqueue *kq = kn->kn_fp->f_data; 340 341 kn->kn_data = kq->kq_count; 342 return (kn->kn_data > 0); 343 } 344 345 /* XXX - move to kern_proc.c? */ 346 static int 347 filt_procattach(struct knote *kn) 348 { 349 struct proc *p; 350 int immediate; 351 int error; 352 353 immediate = 0; 354 p = pfind(kn->kn_id); 355 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 356 p = zpfind(kn->kn_id); 357 immediate = 1; 358 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 359 immediate = 1; 360 } 361 362 if (p == NULL) 363 return (ESRCH); 364 if ((error = p_cansee(curthread, p))) { 365 PROC_UNLOCK(p); 366 return (error); 367 } 368 369 kn->kn_ptr.p_proc = p; 370 kn->kn_flags |= EV_CLEAR; /* automatically set */ 371 372 /* 373 * internal flag indicating registration done by kernel 374 */ 375 if (kn->kn_flags & EV_FLAG1) { 376 kn->kn_data = kn->kn_sdata; /* ppid */ 377 kn->kn_fflags = NOTE_CHILD; 378 kn->kn_flags &= ~EV_FLAG1; 379 } 380 381 if (immediate == 0) 382 knlist_add(&p->p_klist, kn, 1); 383 384 /* 385 * Immediately activate any exit notes if the target process is a 386 * zombie. This is necessary to handle the case where the target 387 * process, e.g. a child, dies before the kevent is registered. 388 */ 389 if (immediate && filt_proc(kn, NOTE_EXIT)) 390 KNOTE_ACTIVATE(kn, 0); 391 392 PROC_UNLOCK(p); 393 394 return (0); 395 } 396 397 /* 398 * The knote may be attached to a different process, which may exit, 399 * leaving nothing for the knote to be attached to. So when the process 400 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 401 * it will be deleted when read out. However, as part of the knote deletion, 402 * this routine is called, so a check is needed to avoid actually performing 403 * a detach, because the original process does not exist any more. 404 */ 405 /* XXX - move to kern_proc.c? */ 406 static void 407 filt_procdetach(struct knote *kn) 408 { 409 struct proc *p; 410 411 p = kn->kn_ptr.p_proc; 412 knlist_remove(&p->p_klist, kn, 0); 413 kn->kn_ptr.p_proc = NULL; 414 } 415 416 /* XXX - move to kern_proc.c? */ 417 static int 418 filt_proc(struct knote *kn, long hint) 419 { 420 struct proc *p = kn->kn_ptr.p_proc; 421 u_int event; 422 423 /* 424 * mask off extra data 425 */ 426 event = (u_int)hint & NOTE_PCTRLMASK; 427 428 /* 429 * if the user is interested in this event, record it. 430 */ 431 if (kn->kn_sfflags & event) 432 kn->kn_fflags |= event; 433 434 /* 435 * process is gone, so flag the event as finished. 436 */ 437 if (event == NOTE_EXIT) { 438 if (!(kn->kn_status & KN_DETACHED)) 439 knlist_remove_inevent(&p->p_klist, kn); 440 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 441 kn->kn_ptr.p_proc = NULL; 442 if (kn->kn_fflags & NOTE_EXIT) 443 kn->kn_data = p->p_xstat; 444 if (kn->kn_fflags == 0) 445 kn->kn_flags |= EV_DROP; 446 return (1); 447 } 448 449 return (kn->kn_fflags != 0); 450 } 451 452 /* 453 * Called when the process forked. It mostly does the same as the 454 * knote(), activating all knotes registered to be activated when the 455 * process forked. Additionally, for each knote attached to the 456 * parent, check whether user wants to track the new process. If so 457 * attach a new knote to it, and immediately report an event with the 458 * child's pid. 459 */ 460 void 461 knote_fork(struct knlist *list, int pid) 462 { 463 struct kqueue *kq; 464 struct knote *kn; 465 struct kevent kev; 466 int error; 467 468 if (list == NULL) 469 return; 470 list->kl_lock(list->kl_lockarg); 471 472 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 473 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) 474 continue; 475 kq = kn->kn_kq; 476 KQ_LOCK(kq); 477 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 478 KQ_UNLOCK(kq); 479 continue; 480 } 481 482 /* 483 * The same as knote(), activate the event. 484 */ 485 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 486 kn->kn_status |= KN_HASKQLOCK; 487 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 488 KNOTE_ACTIVATE(kn, 1); 489 kn->kn_status &= ~KN_HASKQLOCK; 490 KQ_UNLOCK(kq); 491 continue; 492 } 493 494 /* 495 * The NOTE_TRACK case. In addition to the activation 496 * of the event, we need to register new event to 497 * track the child. Drop the locks in preparation for 498 * the call to kqueue_register(). 499 */ 500 kn->kn_status |= KN_INFLUX; 501 KQ_UNLOCK(kq); 502 list->kl_unlock(list->kl_lockarg); 503 504 /* 505 * Activate existing knote and register a knote with 506 * new process. 507 */ 508 kev.ident = pid; 509 kev.filter = kn->kn_filter; 510 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 511 kev.fflags = kn->kn_sfflags; 512 kev.data = kn->kn_id; /* parent */ 513 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 514 error = kqueue_register(kq, &kev, NULL, 0); 515 if (error) 516 kn->kn_fflags |= NOTE_TRACKERR; 517 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 518 KNOTE_ACTIVATE(kn, 0); 519 KQ_LOCK(kq); 520 kn->kn_status &= ~KN_INFLUX; 521 KQ_UNLOCK_FLUX(kq); 522 list->kl_lock(list->kl_lockarg); 523 } 524 list->kl_unlock(list->kl_lockarg); 525 } 526 527 /* 528 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 529 * interval timer support code. 530 */ 531 static __inline sbintime_t 532 timer2sbintime(intptr_t data) 533 { 534 535 #ifdef __LP64__ 536 if (data > INT64_MAX / SBT_1MS) 537 return INT64_MAX; 538 #endif 539 return (SBT_1MS * data); 540 } 541 542 static void 543 filt_timerexpire(void *knx) 544 { 545 struct callout *calloutp; 546 struct knote *kn; 547 548 kn = knx; 549 kn->kn_data++; 550 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 551 552 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 553 calloutp = (struct callout *)kn->kn_hook; 554 callout_reset_sbt_on(calloutp, 555 timer2sbintime(kn->kn_sdata), 0 /* 1ms? */, 556 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 557 } 558 } 559 560 /* 561 * data contains amount of time to sleep, in milliseconds 562 */ 563 static int 564 filt_timerattach(struct knote *kn) 565 { 566 struct callout *calloutp; 567 sbintime_t to; 568 unsigned int ncallouts; 569 570 if ((intptr_t)kn->kn_sdata < 0) 571 return (EINVAL); 572 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 573 kn->kn_sdata = 1; 574 to = timer2sbintime(kn->kn_sdata); 575 if (to < 0) 576 return (EINVAL); 577 578 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed); 579 do { 580 if (ncallouts >= kq_calloutmax) 581 return (ENOMEM); 582 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts, 583 &ncallouts, ncallouts + 1, memory_order_relaxed, 584 memory_order_relaxed)); 585 586 kn->kn_flags |= EV_CLEAR; /* automatically set */ 587 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 588 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 589 callout_init(calloutp, CALLOUT_MPSAFE); 590 kn->kn_hook = calloutp; 591 callout_reset_sbt_on(calloutp, to, 0 /* 1ms? */, 592 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 593 594 return (0); 595 } 596 597 static void 598 filt_timerdetach(struct knote *kn) 599 { 600 struct callout *calloutp; 601 unsigned int old; 602 603 calloutp = (struct callout *)kn->kn_hook; 604 callout_drain(calloutp); 605 free(calloutp, M_KQUEUE); 606 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed); 607 KASSERT(old > 0, ("Number of callouts cannot become negative")); 608 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 609 } 610 611 static int 612 filt_timer(struct knote *kn, long hint) 613 { 614 615 return (kn->kn_data != 0); 616 } 617 618 static int 619 filt_userattach(struct knote *kn) 620 { 621 622 /* 623 * EVFILT_USER knotes are not attached to anything in the kernel. 624 */ 625 kn->kn_hook = NULL; 626 if (kn->kn_fflags & NOTE_TRIGGER) 627 kn->kn_hookid = 1; 628 else 629 kn->kn_hookid = 0; 630 return (0); 631 } 632 633 static void 634 filt_userdetach(__unused struct knote *kn) 635 { 636 637 /* 638 * EVFILT_USER knotes are not attached to anything in the kernel. 639 */ 640 } 641 642 static int 643 filt_user(struct knote *kn, __unused long hint) 644 { 645 646 return (kn->kn_hookid); 647 } 648 649 static void 650 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 651 { 652 u_int ffctrl; 653 654 switch (type) { 655 case EVENT_REGISTER: 656 if (kev->fflags & NOTE_TRIGGER) 657 kn->kn_hookid = 1; 658 659 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 660 kev->fflags &= NOTE_FFLAGSMASK; 661 switch (ffctrl) { 662 case NOTE_FFNOP: 663 break; 664 665 case NOTE_FFAND: 666 kn->kn_sfflags &= kev->fflags; 667 break; 668 669 case NOTE_FFOR: 670 kn->kn_sfflags |= kev->fflags; 671 break; 672 673 case NOTE_FFCOPY: 674 kn->kn_sfflags = kev->fflags; 675 break; 676 677 default: 678 /* XXX Return error? */ 679 break; 680 } 681 kn->kn_sdata = kev->data; 682 if (kev->flags & EV_CLEAR) { 683 kn->kn_hookid = 0; 684 kn->kn_data = 0; 685 kn->kn_fflags = 0; 686 } 687 break; 688 689 case EVENT_PROCESS: 690 *kev = kn->kn_kevent; 691 kev->fflags = kn->kn_sfflags; 692 kev->data = kn->kn_sdata; 693 if (kn->kn_flags & EV_CLEAR) { 694 kn->kn_hookid = 0; 695 kn->kn_data = 0; 696 kn->kn_fflags = 0; 697 } 698 break; 699 700 default: 701 panic("filt_usertouch() - invalid type (%ld)", type); 702 break; 703 } 704 } 705 706 int 707 sys_kqueue(struct thread *td, struct kqueue_args *uap) 708 { 709 struct filedesc *fdp; 710 struct kqueue *kq; 711 struct file *fp; 712 struct proc *p; 713 struct ucred *cred; 714 int fd, error; 715 716 p = td->td_proc; 717 cred = td->td_ucred; 718 crhold(cred); 719 PROC_LOCK(p); 720 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td->td_proc, 721 RLIMIT_KQUEUES))) { 722 PROC_UNLOCK(p); 723 crfree(cred); 724 return (ENOMEM); 725 } 726 PROC_UNLOCK(p); 727 728 fdp = p->p_fd; 729 error = falloc(td, &fp, &fd, 0); 730 if (error) 731 goto done2; 732 733 /* An extra reference on `fp' has been held for us by falloc(). */ 734 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 735 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 736 TAILQ_INIT(&kq->kq_head); 737 kq->kq_fdp = fdp; 738 kq->kq_cred = cred; 739 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 740 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 741 742 FILEDESC_XLOCK(fdp); 743 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 744 FILEDESC_XUNLOCK(fdp); 745 746 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 747 fdrop(fp, td); 748 749 td->td_retval[0] = fd; 750 done2: 751 if (error != 0) { 752 chgkqcnt(cred->cr_ruidinfo, -1, 0); 753 crfree(cred); 754 } 755 return (error); 756 } 757 758 #ifndef _SYS_SYSPROTO_H_ 759 struct kevent_args { 760 int fd; 761 const struct kevent *changelist; 762 int nchanges; 763 struct kevent *eventlist; 764 int nevents; 765 const struct timespec *timeout; 766 }; 767 #endif 768 int 769 sys_kevent(struct thread *td, struct kevent_args *uap) 770 { 771 struct timespec ts, *tsp; 772 struct kevent_copyops k_ops = { uap, 773 kevent_copyout, 774 kevent_copyin}; 775 int error; 776 #ifdef KTRACE 777 struct uio ktruio; 778 struct iovec ktriov; 779 struct uio *ktruioin = NULL; 780 struct uio *ktruioout = NULL; 781 #endif 782 783 if (uap->timeout != NULL) { 784 error = copyin(uap->timeout, &ts, sizeof(ts)); 785 if (error) 786 return (error); 787 tsp = &ts; 788 } else 789 tsp = NULL; 790 791 #ifdef KTRACE 792 if (KTRPOINT(td, KTR_GENIO)) { 793 ktriov.iov_base = uap->changelist; 794 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 795 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 796 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 797 .uio_td = td }; 798 ktruioin = cloneuio(&ktruio); 799 ktriov.iov_base = uap->eventlist; 800 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 801 ktruioout = cloneuio(&ktruio); 802 } 803 #endif 804 805 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 806 &k_ops, tsp); 807 808 #ifdef KTRACE 809 if (ktruioin != NULL) { 810 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 811 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 812 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 813 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 814 } 815 #endif 816 817 return (error); 818 } 819 820 /* 821 * Copy 'count' items into the destination list pointed to by uap->eventlist. 822 */ 823 static int 824 kevent_copyout(void *arg, struct kevent *kevp, int count) 825 { 826 struct kevent_args *uap; 827 int error; 828 829 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 830 uap = (struct kevent_args *)arg; 831 832 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 833 if (error == 0) 834 uap->eventlist += count; 835 return (error); 836 } 837 838 /* 839 * Copy 'count' items from the list pointed to by uap->changelist. 840 */ 841 static int 842 kevent_copyin(void *arg, struct kevent *kevp, int count) 843 { 844 struct kevent_args *uap; 845 int error; 846 847 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 848 uap = (struct kevent_args *)arg; 849 850 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 851 if (error == 0) 852 uap->changelist += count; 853 return (error); 854 } 855 856 int 857 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 858 struct kevent_copyops *k_ops, const struct timespec *timeout) 859 { 860 struct kevent keva[KQ_NEVENTS]; 861 struct kevent *kevp, *changes; 862 struct kqueue *kq; 863 struct file *fp; 864 cap_rights_t rights; 865 int i, n, nerrors, error; 866 867 cap_rights_init(&rights); 868 if (nchanges > 0) 869 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 870 if (nevents > 0) 871 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 872 error = fget(td, fd, &rights, &fp); 873 if (error != 0) 874 return (error); 875 876 error = kqueue_acquire(fp, &kq); 877 if (error != 0) 878 goto done_norel; 879 880 nerrors = 0; 881 882 while (nchanges > 0) { 883 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 884 error = k_ops->k_copyin(k_ops->arg, keva, n); 885 if (error) 886 goto done; 887 changes = keva; 888 for (i = 0; i < n; i++) { 889 kevp = &changes[i]; 890 if (!kevp->filter) 891 continue; 892 kevp->flags &= ~EV_SYSFLAGS; 893 error = kqueue_register(kq, kevp, td, 1); 894 if (error || (kevp->flags & EV_RECEIPT)) { 895 if (nevents != 0) { 896 kevp->flags = EV_ERROR; 897 kevp->data = error; 898 (void) k_ops->k_copyout(k_ops->arg, 899 kevp, 1); 900 nevents--; 901 nerrors++; 902 } else { 903 goto done; 904 } 905 } 906 } 907 nchanges -= n; 908 } 909 if (nerrors) { 910 td->td_retval[0] = nerrors; 911 error = 0; 912 goto done; 913 } 914 915 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 916 done: 917 kqueue_release(kq, 0); 918 done_norel: 919 fdrop(fp, td); 920 return (error); 921 } 922 923 int 924 kqueue_add_filteropts(int filt, struct filterops *filtops) 925 { 926 int error; 927 928 error = 0; 929 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 930 printf( 931 "trying to add a filterop that is out of range: %d is beyond %d\n", 932 ~filt, EVFILT_SYSCOUNT); 933 return EINVAL; 934 } 935 mtx_lock(&filterops_lock); 936 if (sysfilt_ops[~filt].for_fop != &null_filtops && 937 sysfilt_ops[~filt].for_fop != NULL) 938 error = EEXIST; 939 else { 940 sysfilt_ops[~filt].for_fop = filtops; 941 sysfilt_ops[~filt].for_refcnt = 0; 942 } 943 mtx_unlock(&filterops_lock); 944 945 return (error); 946 } 947 948 int 949 kqueue_del_filteropts(int filt) 950 { 951 int error; 952 953 error = 0; 954 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 955 return EINVAL; 956 957 mtx_lock(&filterops_lock); 958 if (sysfilt_ops[~filt].for_fop == &null_filtops || 959 sysfilt_ops[~filt].for_fop == NULL) 960 error = EINVAL; 961 else if (sysfilt_ops[~filt].for_refcnt != 0) 962 error = EBUSY; 963 else { 964 sysfilt_ops[~filt].for_fop = &null_filtops; 965 sysfilt_ops[~filt].for_refcnt = 0; 966 } 967 mtx_unlock(&filterops_lock); 968 969 return error; 970 } 971 972 static struct filterops * 973 kqueue_fo_find(int filt) 974 { 975 976 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 977 return NULL; 978 979 mtx_lock(&filterops_lock); 980 sysfilt_ops[~filt].for_refcnt++; 981 if (sysfilt_ops[~filt].for_fop == NULL) 982 sysfilt_ops[~filt].for_fop = &null_filtops; 983 mtx_unlock(&filterops_lock); 984 985 return sysfilt_ops[~filt].for_fop; 986 } 987 988 static void 989 kqueue_fo_release(int filt) 990 { 991 992 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 993 return; 994 995 mtx_lock(&filterops_lock); 996 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 997 ("filter object refcount not valid on release")); 998 sysfilt_ops[~filt].for_refcnt--; 999 mtx_unlock(&filterops_lock); 1000 } 1001 1002 /* 1003 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 1004 * influence if memory allocation should wait. Make sure it is 0 if you 1005 * hold any mutexes. 1006 */ 1007 static int 1008 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1009 { 1010 struct filterops *fops; 1011 struct file *fp; 1012 struct knote *kn, *tkn; 1013 cap_rights_t rights; 1014 int error, filt, event; 1015 int haskqglobal, filedesc_unlock; 1016 1017 fp = NULL; 1018 kn = NULL; 1019 error = 0; 1020 haskqglobal = 0; 1021 filedesc_unlock = 0; 1022 1023 filt = kev->filter; 1024 fops = kqueue_fo_find(filt); 1025 if (fops == NULL) 1026 return EINVAL; 1027 1028 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1029 1030 findkn: 1031 if (fops->f_isfd) { 1032 KASSERT(td != NULL, ("td is NULL")); 1033 error = fget(td, kev->ident, 1034 cap_rights_init(&rights, CAP_EVENT), &fp); 1035 if (error) 1036 goto done; 1037 1038 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1039 kev->ident, 0) != 0) { 1040 /* try again */ 1041 fdrop(fp, td); 1042 fp = NULL; 1043 error = kqueue_expand(kq, fops, kev->ident, waitok); 1044 if (error) 1045 goto done; 1046 goto findkn; 1047 } 1048 1049 if (fp->f_type == DTYPE_KQUEUE) { 1050 /* 1051 * if we add some inteligence about what we are doing, 1052 * we should be able to support events on ourselves. 1053 * We need to know when we are doing this to prevent 1054 * getting both the knlist lock and the kq lock since 1055 * they are the same thing. 1056 */ 1057 if (fp->f_data == kq) { 1058 error = EINVAL; 1059 goto done; 1060 } 1061 1062 /* 1063 * Pre-lock the filedesc before the global 1064 * lock mutex, see the comment in 1065 * kqueue_close(). 1066 */ 1067 FILEDESC_XLOCK(td->td_proc->p_fd); 1068 filedesc_unlock = 1; 1069 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1070 } 1071 1072 KQ_LOCK(kq); 1073 if (kev->ident < kq->kq_knlistsize) { 1074 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1075 if (kev->filter == kn->kn_filter) 1076 break; 1077 } 1078 } else { 1079 if ((kev->flags & EV_ADD) == EV_ADD) 1080 kqueue_expand(kq, fops, kev->ident, waitok); 1081 1082 KQ_LOCK(kq); 1083 if (kq->kq_knhashmask != 0) { 1084 struct klist *list; 1085 1086 list = &kq->kq_knhash[ 1087 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1088 SLIST_FOREACH(kn, list, kn_link) 1089 if (kev->ident == kn->kn_id && 1090 kev->filter == kn->kn_filter) 1091 break; 1092 } 1093 } 1094 1095 /* knote is in the process of changing, wait for it to stablize. */ 1096 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1097 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1098 if (filedesc_unlock) { 1099 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1100 filedesc_unlock = 0; 1101 } 1102 kq->kq_state |= KQ_FLUXWAIT; 1103 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1104 if (fp != NULL) { 1105 fdrop(fp, td); 1106 fp = NULL; 1107 } 1108 goto findkn; 1109 } 1110 1111 /* 1112 * kn now contains the matching knote, or NULL if no match 1113 */ 1114 if (kn == NULL) { 1115 if (kev->flags & EV_ADD) { 1116 kn = tkn; 1117 tkn = NULL; 1118 if (kn == NULL) { 1119 KQ_UNLOCK(kq); 1120 error = ENOMEM; 1121 goto done; 1122 } 1123 kn->kn_fp = fp; 1124 kn->kn_kq = kq; 1125 kn->kn_fop = fops; 1126 /* 1127 * apply reference counts to knote structure, and 1128 * do not release it at the end of this routine. 1129 */ 1130 fops = NULL; 1131 fp = NULL; 1132 1133 kn->kn_sfflags = kev->fflags; 1134 kn->kn_sdata = kev->data; 1135 kev->fflags = 0; 1136 kev->data = 0; 1137 kn->kn_kevent = *kev; 1138 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1139 EV_ENABLE | EV_DISABLE); 1140 kn->kn_status = KN_INFLUX|KN_DETACHED; 1141 1142 error = knote_attach(kn, kq); 1143 KQ_UNLOCK(kq); 1144 if (error != 0) { 1145 tkn = kn; 1146 goto done; 1147 } 1148 1149 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1150 knote_drop(kn, td); 1151 goto done; 1152 } 1153 KN_LIST_LOCK(kn); 1154 goto done_ev_add; 1155 } else { 1156 /* No matching knote and the EV_ADD flag is not set. */ 1157 KQ_UNLOCK(kq); 1158 error = ENOENT; 1159 goto done; 1160 } 1161 } 1162 1163 if (kev->flags & EV_DELETE) { 1164 kn->kn_status |= KN_INFLUX; 1165 KQ_UNLOCK(kq); 1166 if (!(kn->kn_status & KN_DETACHED)) 1167 kn->kn_fop->f_detach(kn); 1168 knote_drop(kn, td); 1169 goto done; 1170 } 1171 1172 /* 1173 * The user may change some filter values after the initial EV_ADD, 1174 * but doing so will not reset any filter which has already been 1175 * triggered. 1176 */ 1177 kn->kn_status |= KN_INFLUX; 1178 KQ_UNLOCK(kq); 1179 KN_LIST_LOCK(kn); 1180 kn->kn_kevent.udata = kev->udata; 1181 if (!fops->f_isfd && fops->f_touch != NULL) { 1182 fops->f_touch(kn, kev, EVENT_REGISTER); 1183 } else { 1184 kn->kn_sfflags = kev->fflags; 1185 kn->kn_sdata = kev->data; 1186 } 1187 1188 /* 1189 * We can get here with kn->kn_knlist == NULL. This can happen when 1190 * the initial attach event decides that the event is "completed" 1191 * already. i.e. filt_procattach is called on a zombie process. It 1192 * will call filt_proc which will remove it from the list, and NULL 1193 * kn_knlist. 1194 */ 1195 done_ev_add: 1196 event = kn->kn_fop->f_event(kn, 0); 1197 KQ_LOCK(kq); 1198 if (event) 1199 KNOTE_ACTIVATE(kn, 1); 1200 kn->kn_status &= ~KN_INFLUX; 1201 KN_LIST_UNLOCK(kn); 1202 1203 if ((kev->flags & EV_DISABLE) && 1204 ((kn->kn_status & KN_DISABLED) == 0)) { 1205 kn->kn_status |= KN_DISABLED; 1206 } 1207 1208 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1209 kn->kn_status &= ~KN_DISABLED; 1210 if ((kn->kn_status & KN_ACTIVE) && 1211 ((kn->kn_status & KN_QUEUED) == 0)) 1212 knote_enqueue(kn); 1213 } 1214 KQ_UNLOCK_FLUX(kq); 1215 1216 done: 1217 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1218 if (filedesc_unlock) 1219 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1220 if (fp != NULL) 1221 fdrop(fp, td); 1222 if (tkn != NULL) 1223 knote_free(tkn); 1224 if (fops != NULL) 1225 kqueue_fo_release(filt); 1226 return (error); 1227 } 1228 1229 static int 1230 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1231 { 1232 int error; 1233 struct kqueue *kq; 1234 1235 error = 0; 1236 1237 kq = fp->f_data; 1238 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1239 return (EBADF); 1240 *kqp = kq; 1241 KQ_LOCK(kq); 1242 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1243 KQ_UNLOCK(kq); 1244 return (EBADF); 1245 } 1246 kq->kq_refcnt++; 1247 KQ_UNLOCK(kq); 1248 1249 return error; 1250 } 1251 1252 static void 1253 kqueue_release(struct kqueue *kq, int locked) 1254 { 1255 if (locked) 1256 KQ_OWNED(kq); 1257 else 1258 KQ_LOCK(kq); 1259 kq->kq_refcnt--; 1260 if (kq->kq_refcnt == 1) 1261 wakeup(&kq->kq_refcnt); 1262 if (!locked) 1263 KQ_UNLOCK(kq); 1264 } 1265 1266 static void 1267 kqueue_schedtask(struct kqueue *kq) 1268 { 1269 1270 KQ_OWNED(kq); 1271 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1272 ("scheduling kqueue task while draining")); 1273 1274 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1275 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1276 kq->kq_state |= KQ_TASKSCHED; 1277 } 1278 } 1279 1280 /* 1281 * Expand the kq to make sure we have storage for fops/ident pair. 1282 * 1283 * Return 0 on success (or no work necessary), return errno on failure. 1284 * 1285 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1286 * If kqueue_register is called from a non-fd context, there usually/should 1287 * be no locks held. 1288 */ 1289 static int 1290 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1291 int waitok) 1292 { 1293 struct klist *list, *tmp_knhash, *to_free; 1294 u_long tmp_knhashmask; 1295 int size; 1296 int fd; 1297 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1298 1299 KQ_NOTOWNED(kq); 1300 1301 to_free = NULL; 1302 if (fops->f_isfd) { 1303 fd = ident; 1304 if (kq->kq_knlistsize <= fd) { 1305 size = kq->kq_knlistsize; 1306 while (size <= fd) 1307 size += KQEXTENT; 1308 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1309 if (list == NULL) 1310 return ENOMEM; 1311 KQ_LOCK(kq); 1312 if (kq->kq_knlistsize > fd) { 1313 to_free = list; 1314 list = NULL; 1315 } else { 1316 if (kq->kq_knlist != NULL) { 1317 bcopy(kq->kq_knlist, list, 1318 kq->kq_knlistsize * sizeof(*list)); 1319 to_free = kq->kq_knlist; 1320 kq->kq_knlist = NULL; 1321 } 1322 bzero((caddr_t)list + 1323 kq->kq_knlistsize * sizeof(*list), 1324 (size - kq->kq_knlistsize) * sizeof(*list)); 1325 kq->kq_knlistsize = size; 1326 kq->kq_knlist = list; 1327 } 1328 KQ_UNLOCK(kq); 1329 } 1330 } else { 1331 if (kq->kq_knhashmask == 0) { 1332 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1333 &tmp_knhashmask); 1334 if (tmp_knhash == NULL) 1335 return ENOMEM; 1336 KQ_LOCK(kq); 1337 if (kq->kq_knhashmask == 0) { 1338 kq->kq_knhash = tmp_knhash; 1339 kq->kq_knhashmask = tmp_knhashmask; 1340 } else { 1341 to_free = tmp_knhash; 1342 } 1343 KQ_UNLOCK(kq); 1344 } 1345 } 1346 free(to_free, M_KQUEUE); 1347 1348 KQ_NOTOWNED(kq); 1349 return 0; 1350 } 1351 1352 static void 1353 kqueue_task(void *arg, int pending) 1354 { 1355 struct kqueue *kq; 1356 int haskqglobal; 1357 1358 haskqglobal = 0; 1359 kq = arg; 1360 1361 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1362 KQ_LOCK(kq); 1363 1364 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1365 1366 kq->kq_state &= ~KQ_TASKSCHED; 1367 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1368 wakeup(&kq->kq_state); 1369 } 1370 KQ_UNLOCK(kq); 1371 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1372 } 1373 1374 /* 1375 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1376 * We treat KN_MARKER knotes as if they are INFLUX. 1377 */ 1378 static int 1379 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1380 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1381 { 1382 struct kevent *kevp; 1383 struct knote *kn, *marker; 1384 sbintime_t asbt, rsbt; 1385 int count, error, haskqglobal, influx, nkev, touch; 1386 1387 count = maxevents; 1388 nkev = 0; 1389 error = 0; 1390 haskqglobal = 0; 1391 1392 if (maxevents == 0) 1393 goto done_nl; 1394 1395 rsbt = 0; 1396 if (tsp != NULL) { 1397 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1398 tsp->tv_nsec >= 1000000000) { 1399 error = EINVAL; 1400 goto done_nl; 1401 } 1402 if (timespecisset(tsp)) { 1403 if (tsp->tv_sec <= INT32_MAX) { 1404 rsbt = tstosbt(*tsp); 1405 if (TIMESEL(&asbt, rsbt)) 1406 asbt += tc_tick_sbt; 1407 if (asbt <= INT64_MAX - rsbt) 1408 asbt += rsbt; 1409 else 1410 asbt = 0; 1411 rsbt >>= tc_precexp; 1412 } else 1413 asbt = 0; 1414 } else 1415 asbt = -1; 1416 } else 1417 asbt = 0; 1418 marker = knote_alloc(1); 1419 if (marker == NULL) { 1420 error = ENOMEM; 1421 goto done_nl; 1422 } 1423 marker->kn_status = KN_MARKER; 1424 KQ_LOCK(kq); 1425 1426 retry: 1427 kevp = keva; 1428 if (kq->kq_count == 0) { 1429 if (asbt == -1) { 1430 error = EWOULDBLOCK; 1431 } else { 1432 kq->kq_state |= KQ_SLEEP; 1433 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1434 "kqread", asbt, rsbt, C_ABSOLUTE); 1435 } 1436 if (error == 0) 1437 goto retry; 1438 /* don't restart after signals... */ 1439 if (error == ERESTART) 1440 error = EINTR; 1441 else if (error == EWOULDBLOCK) 1442 error = 0; 1443 goto done; 1444 } 1445 1446 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1447 influx = 0; 1448 while (count) { 1449 KQ_OWNED(kq); 1450 kn = TAILQ_FIRST(&kq->kq_head); 1451 1452 if ((kn->kn_status == KN_MARKER && kn != marker) || 1453 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1454 if (influx) { 1455 influx = 0; 1456 KQ_FLUX_WAKEUP(kq); 1457 } 1458 kq->kq_state |= KQ_FLUXWAIT; 1459 error = msleep(kq, &kq->kq_lock, PSOCK, 1460 "kqflxwt", 0); 1461 continue; 1462 } 1463 1464 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1465 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1466 kn->kn_status &= ~KN_QUEUED; 1467 kq->kq_count--; 1468 continue; 1469 } 1470 if (kn == marker) { 1471 KQ_FLUX_WAKEUP(kq); 1472 if (count == maxevents) 1473 goto retry; 1474 goto done; 1475 } 1476 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1477 ("KN_INFLUX set when not suppose to be")); 1478 1479 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1480 kn->kn_status &= ~KN_QUEUED; 1481 kn->kn_status |= KN_INFLUX; 1482 kq->kq_count--; 1483 KQ_UNLOCK(kq); 1484 /* 1485 * We don't need to lock the list since we've marked 1486 * it _INFLUX. 1487 */ 1488 if (!(kn->kn_status & KN_DETACHED)) 1489 kn->kn_fop->f_detach(kn); 1490 knote_drop(kn, td); 1491 KQ_LOCK(kq); 1492 continue; 1493 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1494 kn->kn_status &= ~KN_QUEUED; 1495 kn->kn_status |= KN_INFLUX; 1496 kq->kq_count--; 1497 KQ_UNLOCK(kq); 1498 /* 1499 * We don't need to lock the list since we've marked 1500 * it _INFLUX. 1501 */ 1502 *kevp = kn->kn_kevent; 1503 if (!(kn->kn_status & KN_DETACHED)) 1504 kn->kn_fop->f_detach(kn); 1505 knote_drop(kn, td); 1506 KQ_LOCK(kq); 1507 kn = NULL; 1508 } else { 1509 kn->kn_status |= KN_INFLUX; 1510 KQ_UNLOCK(kq); 1511 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1512 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1513 KN_LIST_LOCK(kn); 1514 if (kn->kn_fop->f_event(kn, 0) == 0) { 1515 KQ_LOCK(kq); 1516 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1517 kn->kn_status &= 1518 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX); 1519 kq->kq_count--; 1520 KN_LIST_UNLOCK(kn); 1521 influx = 1; 1522 continue; 1523 } 1524 touch = (!kn->kn_fop->f_isfd && 1525 kn->kn_fop->f_touch != NULL); 1526 if (touch) 1527 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1528 else 1529 *kevp = kn->kn_kevent; 1530 KQ_LOCK(kq); 1531 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1532 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1533 /* 1534 * Manually clear knotes who weren't 1535 * 'touch'ed. 1536 */ 1537 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1538 kn->kn_data = 0; 1539 kn->kn_fflags = 0; 1540 } 1541 if (kn->kn_flags & EV_DISPATCH) 1542 kn->kn_status |= KN_DISABLED; 1543 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1544 kq->kq_count--; 1545 } else 1546 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1547 1548 kn->kn_status &= ~(KN_INFLUX); 1549 KN_LIST_UNLOCK(kn); 1550 influx = 1; 1551 } 1552 1553 /* we are returning a copy to the user */ 1554 kevp++; 1555 nkev++; 1556 count--; 1557 1558 if (nkev == KQ_NEVENTS) { 1559 influx = 0; 1560 KQ_UNLOCK_FLUX(kq); 1561 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1562 nkev = 0; 1563 kevp = keva; 1564 KQ_LOCK(kq); 1565 if (error) 1566 break; 1567 } 1568 } 1569 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1570 done: 1571 KQ_OWNED(kq); 1572 KQ_UNLOCK_FLUX(kq); 1573 knote_free(marker); 1574 done_nl: 1575 KQ_NOTOWNED(kq); 1576 if (nkev != 0) 1577 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1578 td->td_retval[0] = maxevents - count; 1579 return (error); 1580 } 1581 1582 /* 1583 * XXX 1584 * This could be expanded to call kqueue_scan, if desired. 1585 */ 1586 /*ARGSUSED*/ 1587 static int 1588 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1589 int flags, struct thread *td) 1590 { 1591 return (ENXIO); 1592 } 1593 1594 /*ARGSUSED*/ 1595 static int 1596 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1597 int flags, struct thread *td) 1598 { 1599 return (ENXIO); 1600 } 1601 1602 /*ARGSUSED*/ 1603 static int 1604 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1605 struct thread *td) 1606 { 1607 1608 return (EINVAL); 1609 } 1610 1611 /*ARGSUSED*/ 1612 static int 1613 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1614 struct ucred *active_cred, struct thread *td) 1615 { 1616 /* 1617 * Enabling sigio causes two major problems: 1618 * 1) infinite recursion: 1619 * Synopsys: kevent is being used to track signals and have FIOASYNC 1620 * set. On receipt of a signal this will cause a kqueue to recurse 1621 * into itself over and over. Sending the sigio causes the kqueue 1622 * to become ready, which in turn posts sigio again, forever. 1623 * Solution: this can be solved by setting a flag in the kqueue that 1624 * we have a SIGIO in progress. 1625 * 2) locking problems: 1626 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1627 * us above the proc and pgrp locks. 1628 * Solution: Post a signal using an async mechanism, being sure to 1629 * record a generation count in the delivery so that we do not deliver 1630 * a signal to the wrong process. 1631 * 1632 * Note, these two mechanisms are somewhat mutually exclusive! 1633 */ 1634 #if 0 1635 struct kqueue *kq; 1636 1637 kq = fp->f_data; 1638 switch (cmd) { 1639 case FIOASYNC: 1640 if (*(int *)data) { 1641 kq->kq_state |= KQ_ASYNC; 1642 } else { 1643 kq->kq_state &= ~KQ_ASYNC; 1644 } 1645 return (0); 1646 1647 case FIOSETOWN: 1648 return (fsetown(*(int *)data, &kq->kq_sigio)); 1649 1650 case FIOGETOWN: 1651 *(int *)data = fgetown(&kq->kq_sigio); 1652 return (0); 1653 } 1654 #endif 1655 1656 return (ENOTTY); 1657 } 1658 1659 /*ARGSUSED*/ 1660 static int 1661 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1662 struct thread *td) 1663 { 1664 struct kqueue *kq; 1665 int revents = 0; 1666 int error; 1667 1668 if ((error = kqueue_acquire(fp, &kq))) 1669 return POLLERR; 1670 1671 KQ_LOCK(kq); 1672 if (events & (POLLIN | POLLRDNORM)) { 1673 if (kq->kq_count) { 1674 revents |= events & (POLLIN | POLLRDNORM); 1675 } else { 1676 selrecord(td, &kq->kq_sel); 1677 if (SEL_WAITING(&kq->kq_sel)) 1678 kq->kq_state |= KQ_SEL; 1679 } 1680 } 1681 kqueue_release(kq, 1); 1682 KQ_UNLOCK(kq); 1683 return (revents); 1684 } 1685 1686 /*ARGSUSED*/ 1687 static int 1688 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1689 struct thread *td) 1690 { 1691 1692 bzero((void *)st, sizeof *st); 1693 /* 1694 * We no longer return kq_count because the unlocked value is useless. 1695 * If you spent all this time getting the count, why not spend your 1696 * syscall better by calling kevent? 1697 * 1698 * XXX - This is needed for libc_r. 1699 */ 1700 st->st_mode = S_IFIFO; 1701 return (0); 1702 } 1703 1704 /*ARGSUSED*/ 1705 static int 1706 kqueue_close(struct file *fp, struct thread *td) 1707 { 1708 struct kqueue *kq = fp->f_data; 1709 struct filedesc *fdp; 1710 struct knote *kn; 1711 int i; 1712 int error; 1713 int filedesc_unlock; 1714 1715 if ((error = kqueue_acquire(fp, &kq))) 1716 return error; 1717 1718 filedesc_unlock = 0; 1719 KQ_LOCK(kq); 1720 1721 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1722 ("kqueue already closing")); 1723 kq->kq_state |= KQ_CLOSING; 1724 if (kq->kq_refcnt > 1) 1725 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1726 1727 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1728 fdp = kq->kq_fdp; 1729 1730 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1731 ("kqueue's knlist not empty")); 1732 1733 for (i = 0; i < kq->kq_knlistsize; i++) { 1734 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1735 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1736 kq->kq_state |= KQ_FLUXWAIT; 1737 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1738 continue; 1739 } 1740 kn->kn_status |= KN_INFLUX; 1741 KQ_UNLOCK(kq); 1742 if (!(kn->kn_status & KN_DETACHED)) 1743 kn->kn_fop->f_detach(kn); 1744 knote_drop(kn, td); 1745 KQ_LOCK(kq); 1746 } 1747 } 1748 if (kq->kq_knhashmask != 0) { 1749 for (i = 0; i <= kq->kq_knhashmask; i++) { 1750 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1751 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1752 kq->kq_state |= KQ_FLUXWAIT; 1753 msleep(kq, &kq->kq_lock, PSOCK, 1754 "kqclo2", 0); 1755 continue; 1756 } 1757 kn->kn_status |= KN_INFLUX; 1758 KQ_UNLOCK(kq); 1759 if (!(kn->kn_status & KN_DETACHED)) 1760 kn->kn_fop->f_detach(kn); 1761 knote_drop(kn, td); 1762 KQ_LOCK(kq); 1763 } 1764 } 1765 } 1766 1767 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1768 kq->kq_state |= KQ_TASKDRAIN; 1769 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1770 } 1771 1772 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1773 selwakeuppri(&kq->kq_sel, PSOCK); 1774 if (!SEL_WAITING(&kq->kq_sel)) 1775 kq->kq_state &= ~KQ_SEL; 1776 } 1777 1778 KQ_UNLOCK(kq); 1779 1780 /* 1781 * We could be called due to the knote_drop() doing fdrop(), 1782 * called from kqueue_register(). In this case the global 1783 * lock is owned, and filedesc sx is locked before, to not 1784 * take the sleepable lock after non-sleepable. 1785 */ 1786 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1787 FILEDESC_XLOCK(fdp); 1788 filedesc_unlock = 1; 1789 } else 1790 filedesc_unlock = 0; 1791 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1792 if (filedesc_unlock) 1793 FILEDESC_XUNLOCK(fdp); 1794 1795 seldrain(&kq->kq_sel); 1796 knlist_destroy(&kq->kq_sel.si_note); 1797 mtx_destroy(&kq->kq_lock); 1798 kq->kq_fdp = NULL; 1799 1800 if (kq->kq_knhash != NULL) 1801 free(kq->kq_knhash, M_KQUEUE); 1802 if (kq->kq_knlist != NULL) 1803 free(kq->kq_knlist, M_KQUEUE); 1804 1805 funsetown(&kq->kq_sigio); 1806 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 1807 crfree(kq->kq_cred); 1808 free(kq, M_KQUEUE); 1809 fp->f_data = NULL; 1810 1811 return (0); 1812 } 1813 1814 static void 1815 kqueue_wakeup(struct kqueue *kq) 1816 { 1817 KQ_OWNED(kq); 1818 1819 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1820 kq->kq_state &= ~KQ_SLEEP; 1821 wakeup(kq); 1822 } 1823 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1824 selwakeuppri(&kq->kq_sel, PSOCK); 1825 if (!SEL_WAITING(&kq->kq_sel)) 1826 kq->kq_state &= ~KQ_SEL; 1827 } 1828 if (!knlist_empty(&kq->kq_sel.si_note)) 1829 kqueue_schedtask(kq); 1830 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1831 pgsigio(&kq->kq_sigio, SIGIO, 0); 1832 } 1833 } 1834 1835 /* 1836 * Walk down a list of knotes, activating them if their event has triggered. 1837 * 1838 * There is a possibility to optimize in the case of one kq watching another. 1839 * Instead of scheduling a task to wake it up, you could pass enough state 1840 * down the chain to make up the parent kqueue. Make this code functional 1841 * first. 1842 */ 1843 void 1844 knote(struct knlist *list, long hint, int lockflags) 1845 { 1846 struct kqueue *kq; 1847 struct knote *kn; 1848 int error; 1849 1850 if (list == NULL) 1851 return; 1852 1853 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1854 1855 if ((lockflags & KNF_LISTLOCKED) == 0) 1856 list->kl_lock(list->kl_lockarg); 1857 1858 /* 1859 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1860 * the kqueue scheduling, but this will introduce four 1861 * lock/unlock's for each knote to test. If we do, continue to use 1862 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1863 * only safe if you want to remove the current item, which we are 1864 * not doing. 1865 */ 1866 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1867 kq = kn->kn_kq; 1868 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { 1869 KQ_LOCK(kq); 1870 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1871 KQ_UNLOCK(kq); 1872 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1873 kn->kn_status |= KN_INFLUX; 1874 KQ_UNLOCK(kq); 1875 error = kn->kn_fop->f_event(kn, hint); 1876 KQ_LOCK(kq); 1877 kn->kn_status &= ~KN_INFLUX; 1878 if (error) 1879 KNOTE_ACTIVATE(kn, 1); 1880 KQ_UNLOCK_FLUX(kq); 1881 } else { 1882 kn->kn_status |= KN_HASKQLOCK; 1883 if (kn->kn_fop->f_event(kn, hint)) 1884 KNOTE_ACTIVATE(kn, 1); 1885 kn->kn_status &= ~KN_HASKQLOCK; 1886 KQ_UNLOCK(kq); 1887 } 1888 } 1889 kq = NULL; 1890 } 1891 if ((lockflags & KNF_LISTLOCKED) == 0) 1892 list->kl_unlock(list->kl_lockarg); 1893 } 1894 1895 /* 1896 * add a knote to a knlist 1897 */ 1898 void 1899 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1900 { 1901 KNL_ASSERT_LOCK(knl, islocked); 1902 KQ_NOTOWNED(kn->kn_kq); 1903 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1904 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1905 if (!islocked) 1906 knl->kl_lock(knl->kl_lockarg); 1907 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1908 if (!islocked) 1909 knl->kl_unlock(knl->kl_lockarg); 1910 KQ_LOCK(kn->kn_kq); 1911 kn->kn_knlist = knl; 1912 kn->kn_status &= ~KN_DETACHED; 1913 KQ_UNLOCK(kn->kn_kq); 1914 } 1915 1916 static void 1917 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1918 { 1919 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1920 KNL_ASSERT_LOCK(knl, knlislocked); 1921 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1922 if (!kqislocked) 1923 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1924 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1925 if (!knlislocked) 1926 knl->kl_lock(knl->kl_lockarg); 1927 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1928 kn->kn_knlist = NULL; 1929 if (!knlislocked) 1930 knl->kl_unlock(knl->kl_lockarg); 1931 if (!kqislocked) 1932 KQ_LOCK(kn->kn_kq); 1933 kn->kn_status |= KN_DETACHED; 1934 if (!kqislocked) 1935 KQ_UNLOCK(kn->kn_kq); 1936 } 1937 1938 /* 1939 * remove knote from the specified knlist 1940 */ 1941 void 1942 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1943 { 1944 1945 knlist_remove_kq(knl, kn, islocked, 0); 1946 } 1947 1948 /* 1949 * remove knote from the specified knlist while in f_event handler. 1950 */ 1951 void 1952 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1953 { 1954 1955 knlist_remove_kq(knl, kn, 1, 1956 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1957 } 1958 1959 int 1960 knlist_empty(struct knlist *knl) 1961 { 1962 1963 KNL_ASSERT_LOCKED(knl); 1964 return SLIST_EMPTY(&knl->kl_list); 1965 } 1966 1967 static struct mtx knlist_lock; 1968 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1969 MTX_DEF); 1970 static void knlist_mtx_lock(void *arg); 1971 static void knlist_mtx_unlock(void *arg); 1972 1973 static void 1974 knlist_mtx_lock(void *arg) 1975 { 1976 1977 mtx_lock((struct mtx *)arg); 1978 } 1979 1980 static void 1981 knlist_mtx_unlock(void *arg) 1982 { 1983 1984 mtx_unlock((struct mtx *)arg); 1985 } 1986 1987 static void 1988 knlist_mtx_assert_locked(void *arg) 1989 { 1990 1991 mtx_assert((struct mtx *)arg, MA_OWNED); 1992 } 1993 1994 static void 1995 knlist_mtx_assert_unlocked(void *arg) 1996 { 1997 1998 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 1999 } 2000 2001 static void 2002 knlist_rw_rlock(void *arg) 2003 { 2004 2005 rw_rlock((struct rwlock *)arg); 2006 } 2007 2008 static void 2009 knlist_rw_runlock(void *arg) 2010 { 2011 2012 rw_runlock((struct rwlock *)arg); 2013 } 2014 2015 static void 2016 knlist_rw_assert_locked(void *arg) 2017 { 2018 2019 rw_assert((struct rwlock *)arg, RA_LOCKED); 2020 } 2021 2022 static void 2023 knlist_rw_assert_unlocked(void *arg) 2024 { 2025 2026 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2027 } 2028 2029 void 2030 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2031 void (*kl_unlock)(void *), 2032 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2033 { 2034 2035 if (lock == NULL) 2036 knl->kl_lockarg = &knlist_lock; 2037 else 2038 knl->kl_lockarg = lock; 2039 2040 if (kl_lock == NULL) 2041 knl->kl_lock = knlist_mtx_lock; 2042 else 2043 knl->kl_lock = kl_lock; 2044 if (kl_unlock == NULL) 2045 knl->kl_unlock = knlist_mtx_unlock; 2046 else 2047 knl->kl_unlock = kl_unlock; 2048 if (kl_assert_locked == NULL) 2049 knl->kl_assert_locked = knlist_mtx_assert_locked; 2050 else 2051 knl->kl_assert_locked = kl_assert_locked; 2052 if (kl_assert_unlocked == NULL) 2053 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2054 else 2055 knl->kl_assert_unlocked = kl_assert_unlocked; 2056 2057 SLIST_INIT(&knl->kl_list); 2058 } 2059 2060 void 2061 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2062 { 2063 2064 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2065 } 2066 2067 void 2068 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2069 { 2070 2071 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2072 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2073 } 2074 2075 void 2076 knlist_destroy(struct knlist *knl) 2077 { 2078 2079 #ifdef INVARIANTS 2080 /* 2081 * if we run across this error, we need to find the offending 2082 * driver and have it call knlist_clear or knlist_delete. 2083 */ 2084 if (!SLIST_EMPTY(&knl->kl_list)) 2085 printf("WARNING: destroying knlist w/ knotes on it!\n"); 2086 #endif 2087 2088 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 2089 SLIST_INIT(&knl->kl_list); 2090 } 2091 2092 /* 2093 * Even if we are locked, we may need to drop the lock to allow any influx 2094 * knotes time to "settle". 2095 */ 2096 void 2097 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2098 { 2099 struct knote *kn, *kn2; 2100 struct kqueue *kq; 2101 2102 if (islocked) 2103 KNL_ASSERT_LOCKED(knl); 2104 else { 2105 KNL_ASSERT_UNLOCKED(knl); 2106 again: /* need to reacquire lock since we have dropped it */ 2107 knl->kl_lock(knl->kl_lockarg); 2108 } 2109 2110 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2111 kq = kn->kn_kq; 2112 KQ_LOCK(kq); 2113 if ((kn->kn_status & KN_INFLUX)) { 2114 KQ_UNLOCK(kq); 2115 continue; 2116 } 2117 knlist_remove_kq(knl, kn, 1, 1); 2118 if (killkn) { 2119 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2120 KQ_UNLOCK(kq); 2121 knote_drop(kn, td); 2122 } else { 2123 /* Make sure cleared knotes disappear soon */ 2124 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2125 KQ_UNLOCK(kq); 2126 } 2127 kq = NULL; 2128 } 2129 2130 if (!SLIST_EMPTY(&knl->kl_list)) { 2131 /* there are still KN_INFLUX remaining */ 2132 kn = SLIST_FIRST(&knl->kl_list); 2133 kq = kn->kn_kq; 2134 KQ_LOCK(kq); 2135 KASSERT(kn->kn_status & KN_INFLUX, 2136 ("knote removed w/o list lock")); 2137 knl->kl_unlock(knl->kl_lockarg); 2138 kq->kq_state |= KQ_FLUXWAIT; 2139 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2140 kq = NULL; 2141 goto again; 2142 } 2143 2144 if (islocked) 2145 KNL_ASSERT_LOCKED(knl); 2146 else { 2147 knl->kl_unlock(knl->kl_lockarg); 2148 KNL_ASSERT_UNLOCKED(knl); 2149 } 2150 } 2151 2152 /* 2153 * Remove all knotes referencing a specified fd must be called with FILEDESC 2154 * lock. This prevents a race where a new fd comes along and occupies the 2155 * entry and we attach a knote to the fd. 2156 */ 2157 void 2158 knote_fdclose(struct thread *td, int fd) 2159 { 2160 struct filedesc *fdp = td->td_proc->p_fd; 2161 struct kqueue *kq; 2162 struct knote *kn; 2163 int influx; 2164 2165 FILEDESC_XLOCK_ASSERT(fdp); 2166 2167 /* 2168 * We shouldn't have to worry about new kevents appearing on fd 2169 * since filedesc is locked. 2170 */ 2171 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2172 KQ_LOCK(kq); 2173 2174 again: 2175 influx = 0; 2176 while (kq->kq_knlistsize > fd && 2177 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2178 if (kn->kn_status & KN_INFLUX) { 2179 /* someone else might be waiting on our knote */ 2180 if (influx) 2181 wakeup(kq); 2182 kq->kq_state |= KQ_FLUXWAIT; 2183 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2184 goto again; 2185 } 2186 kn->kn_status |= KN_INFLUX; 2187 KQ_UNLOCK(kq); 2188 if (!(kn->kn_status & KN_DETACHED)) 2189 kn->kn_fop->f_detach(kn); 2190 knote_drop(kn, td); 2191 influx = 1; 2192 KQ_LOCK(kq); 2193 } 2194 KQ_UNLOCK_FLUX(kq); 2195 } 2196 } 2197 2198 static int 2199 knote_attach(struct knote *kn, struct kqueue *kq) 2200 { 2201 struct klist *list; 2202 2203 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2204 KQ_OWNED(kq); 2205 2206 if (kn->kn_fop->f_isfd) { 2207 if (kn->kn_id >= kq->kq_knlistsize) 2208 return ENOMEM; 2209 list = &kq->kq_knlist[kn->kn_id]; 2210 } else { 2211 if (kq->kq_knhash == NULL) 2212 return ENOMEM; 2213 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2214 } 2215 2216 SLIST_INSERT_HEAD(list, kn, kn_link); 2217 2218 return 0; 2219 } 2220 2221 /* 2222 * knote must already have been detached using the f_detach method. 2223 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2224 * to prevent other removal. 2225 */ 2226 static void 2227 knote_drop(struct knote *kn, struct thread *td) 2228 { 2229 struct kqueue *kq; 2230 struct klist *list; 2231 2232 kq = kn->kn_kq; 2233 2234 KQ_NOTOWNED(kq); 2235 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2236 ("knote_drop called without KN_INFLUX set in kn_status")); 2237 2238 KQ_LOCK(kq); 2239 if (kn->kn_fop->f_isfd) 2240 list = &kq->kq_knlist[kn->kn_id]; 2241 else 2242 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2243 2244 if (!SLIST_EMPTY(list)) 2245 SLIST_REMOVE(list, kn, knote, kn_link); 2246 if (kn->kn_status & KN_QUEUED) 2247 knote_dequeue(kn); 2248 KQ_UNLOCK_FLUX(kq); 2249 2250 if (kn->kn_fop->f_isfd) { 2251 fdrop(kn->kn_fp, td); 2252 kn->kn_fp = NULL; 2253 } 2254 kqueue_fo_release(kn->kn_kevent.filter); 2255 kn->kn_fop = NULL; 2256 knote_free(kn); 2257 } 2258 2259 static void 2260 knote_enqueue(struct knote *kn) 2261 { 2262 struct kqueue *kq = kn->kn_kq; 2263 2264 KQ_OWNED(kn->kn_kq); 2265 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2266 2267 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2268 kn->kn_status |= KN_QUEUED; 2269 kq->kq_count++; 2270 kqueue_wakeup(kq); 2271 } 2272 2273 static void 2274 knote_dequeue(struct knote *kn) 2275 { 2276 struct kqueue *kq = kn->kn_kq; 2277 2278 KQ_OWNED(kn->kn_kq); 2279 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2280 2281 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2282 kn->kn_status &= ~KN_QUEUED; 2283 kq->kq_count--; 2284 } 2285 2286 static void 2287 knote_init(void) 2288 { 2289 2290 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2291 NULL, NULL, UMA_ALIGN_PTR, 0); 2292 } 2293 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2294 2295 static struct knote * 2296 knote_alloc(int waitok) 2297 { 2298 return ((struct knote *)uma_zalloc(knote_zone, 2299 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2300 } 2301 2302 static void 2303 knote_free(struct knote *kn) 2304 { 2305 if (kn != NULL) 2306 uma_zfree(knote_zone, kn); 2307 } 2308 2309 /* 2310 * Register the kev w/ the kq specified by fd. 2311 */ 2312 int 2313 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2314 { 2315 struct kqueue *kq; 2316 struct file *fp; 2317 cap_rights_t rights; 2318 int error; 2319 2320 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2321 if (error != 0) 2322 return (error); 2323 if ((error = kqueue_acquire(fp, &kq)) != 0) 2324 goto noacquire; 2325 2326 error = kqueue_register(kq, kev, td, waitok); 2327 2328 kqueue_release(kq, 0); 2329 2330 noacquire: 2331 fdrop(fp, td); 2332 2333 return error; 2334 } 2335