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/capsicum.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 { &file_filtops }, /* EVFILT_PROCDESC */ 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; 421 u_int event; 422 423 p = kn->kn_ptr.p_proc; 424 /* Mask off extra data. */ 425 event = (u_int)hint & NOTE_PCTRLMASK; 426 427 /* If the user is interested in this event, record it. */ 428 if (kn->kn_sfflags & event) 429 kn->kn_fflags |= event; 430 431 /* Process is gone, so flag the event as finished. */ 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_SCAN)) == 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 #ifdef __LP64__ 531 if (data > SBT_MAX / SBT_1MS) 532 return (SBT_MAX); 533 #endif 534 return (SBT_1MS * data); 535 } 536 537 static void 538 filt_timerexpire(void *knx) 539 { 540 struct callout *calloutp; 541 struct knote *kn; 542 543 kn = knx; 544 kn->kn_data++; 545 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 546 547 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 548 calloutp = (struct callout *)kn->kn_hook; 549 callout_reset_sbt_on(calloutp, 550 timer2sbintime(kn->kn_sdata), 0 /* 1ms? */, 551 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 552 } 553 } 554 555 /* 556 * data contains amount of time to sleep, in milliseconds 557 */ 558 static int 559 filt_timerattach(struct knote *kn) 560 { 561 struct callout *calloutp; 562 sbintime_t to; 563 unsigned int ncallouts; 564 565 if ((intptr_t)kn->kn_sdata < 0) 566 return (EINVAL); 567 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 568 kn->kn_sdata = 1; 569 to = timer2sbintime(kn->kn_sdata); 570 if (to < 0) 571 return (EINVAL); 572 573 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed); 574 do { 575 if (ncallouts >= kq_calloutmax) 576 return (ENOMEM); 577 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts, 578 &ncallouts, ncallouts + 1, memory_order_relaxed, 579 memory_order_relaxed)); 580 581 kn->kn_flags |= EV_CLEAR; /* automatically set */ 582 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 583 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 584 callout_init(calloutp, CALLOUT_MPSAFE); 585 kn->kn_hook = calloutp; 586 callout_reset_sbt_on(calloutp, to, 0 /* 1ms? */, 587 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 588 589 return (0); 590 } 591 592 static void 593 filt_timerdetach(struct knote *kn) 594 { 595 struct callout *calloutp; 596 unsigned int old; 597 598 calloutp = (struct callout *)kn->kn_hook; 599 callout_drain(calloutp); 600 free(calloutp, M_KQUEUE); 601 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed); 602 KASSERT(old > 0, ("Number of callouts cannot become negative")); 603 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 604 } 605 606 static int 607 filt_timer(struct knote *kn, long hint) 608 { 609 610 return (kn->kn_data != 0); 611 } 612 613 static int 614 filt_userattach(struct knote *kn) 615 { 616 617 /* 618 * EVFILT_USER knotes are not attached to anything in the kernel. 619 */ 620 kn->kn_hook = NULL; 621 if (kn->kn_fflags & NOTE_TRIGGER) 622 kn->kn_hookid = 1; 623 else 624 kn->kn_hookid = 0; 625 return (0); 626 } 627 628 static void 629 filt_userdetach(__unused struct knote *kn) 630 { 631 632 /* 633 * EVFILT_USER knotes are not attached to anything in the kernel. 634 */ 635 } 636 637 static int 638 filt_user(struct knote *kn, __unused long hint) 639 { 640 641 return (kn->kn_hookid); 642 } 643 644 static void 645 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 646 { 647 u_int ffctrl; 648 649 switch (type) { 650 case EVENT_REGISTER: 651 if (kev->fflags & NOTE_TRIGGER) 652 kn->kn_hookid = 1; 653 654 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 655 kev->fflags &= NOTE_FFLAGSMASK; 656 switch (ffctrl) { 657 case NOTE_FFNOP: 658 break; 659 660 case NOTE_FFAND: 661 kn->kn_sfflags &= kev->fflags; 662 break; 663 664 case NOTE_FFOR: 665 kn->kn_sfflags |= kev->fflags; 666 break; 667 668 case NOTE_FFCOPY: 669 kn->kn_sfflags = kev->fflags; 670 break; 671 672 default: 673 /* XXX Return error? */ 674 break; 675 } 676 kn->kn_sdata = kev->data; 677 if (kev->flags & EV_CLEAR) { 678 kn->kn_hookid = 0; 679 kn->kn_data = 0; 680 kn->kn_fflags = 0; 681 } 682 break; 683 684 case EVENT_PROCESS: 685 *kev = kn->kn_kevent; 686 kev->fflags = kn->kn_sfflags; 687 kev->data = kn->kn_sdata; 688 if (kn->kn_flags & EV_CLEAR) { 689 kn->kn_hookid = 0; 690 kn->kn_data = 0; 691 kn->kn_fflags = 0; 692 } 693 break; 694 695 default: 696 panic("filt_usertouch() - invalid type (%ld)", type); 697 break; 698 } 699 } 700 701 int 702 sys_kqueue(struct thread *td, struct kqueue_args *uap) 703 { 704 struct filedesc *fdp; 705 struct kqueue *kq; 706 struct file *fp; 707 struct proc *p; 708 struct ucred *cred; 709 int fd, error; 710 711 p = td->td_proc; 712 cred = td->td_ucred; 713 crhold(cred); 714 PROC_LOCK(p); 715 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td->td_proc, 716 RLIMIT_KQUEUES))) { 717 PROC_UNLOCK(p); 718 crfree(cred); 719 return (ENOMEM); 720 } 721 PROC_UNLOCK(p); 722 723 fdp = p->p_fd; 724 error = falloc(td, &fp, &fd, 0); 725 if (error) 726 goto done2; 727 728 /* An extra reference on `fp' has been held for us by falloc(). */ 729 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 730 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 731 TAILQ_INIT(&kq->kq_head); 732 kq->kq_fdp = fdp; 733 kq->kq_cred = cred; 734 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 735 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 736 737 FILEDESC_XLOCK(fdp); 738 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 739 FILEDESC_XUNLOCK(fdp); 740 741 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 742 fdrop(fp, td); 743 744 td->td_retval[0] = fd; 745 done2: 746 if (error != 0) { 747 chgkqcnt(cred->cr_ruidinfo, -1, 0); 748 crfree(cred); 749 } 750 return (error); 751 } 752 753 #ifndef _SYS_SYSPROTO_H_ 754 struct kevent_args { 755 int fd; 756 const struct kevent *changelist; 757 int nchanges; 758 struct kevent *eventlist; 759 int nevents; 760 const struct timespec *timeout; 761 }; 762 #endif 763 int 764 sys_kevent(struct thread *td, struct kevent_args *uap) 765 { 766 struct timespec ts, *tsp; 767 struct kevent_copyops k_ops = { uap, 768 kevent_copyout, 769 kevent_copyin}; 770 int error; 771 #ifdef KTRACE 772 struct uio ktruio; 773 struct iovec ktriov; 774 struct uio *ktruioin = NULL; 775 struct uio *ktruioout = NULL; 776 #endif 777 778 if (uap->timeout != NULL) { 779 error = copyin(uap->timeout, &ts, sizeof(ts)); 780 if (error) 781 return (error); 782 tsp = &ts; 783 } else 784 tsp = NULL; 785 786 #ifdef KTRACE 787 if (KTRPOINT(td, KTR_GENIO)) { 788 ktriov.iov_base = uap->changelist; 789 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 790 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 791 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 792 .uio_td = td }; 793 ktruioin = cloneuio(&ktruio); 794 ktriov.iov_base = uap->eventlist; 795 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 796 ktruioout = cloneuio(&ktruio); 797 } 798 #endif 799 800 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 801 &k_ops, tsp); 802 803 #ifdef KTRACE 804 if (ktruioin != NULL) { 805 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 806 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 807 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 808 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 809 } 810 #endif 811 812 return (error); 813 } 814 815 /* 816 * Copy 'count' items into the destination list pointed to by uap->eventlist. 817 */ 818 static int 819 kevent_copyout(void *arg, struct kevent *kevp, int count) 820 { 821 struct kevent_args *uap; 822 int error; 823 824 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 825 uap = (struct kevent_args *)arg; 826 827 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 828 if (error == 0) 829 uap->eventlist += count; 830 return (error); 831 } 832 833 /* 834 * Copy 'count' items from the list pointed to by uap->changelist. 835 */ 836 static int 837 kevent_copyin(void *arg, struct kevent *kevp, int count) 838 { 839 struct kevent_args *uap; 840 int error; 841 842 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 843 uap = (struct kevent_args *)arg; 844 845 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 846 if (error == 0) 847 uap->changelist += count; 848 return (error); 849 } 850 851 int 852 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 853 struct kevent_copyops *k_ops, const struct timespec *timeout) 854 { 855 struct kevent keva[KQ_NEVENTS]; 856 struct kevent *kevp, *changes; 857 struct kqueue *kq; 858 struct file *fp; 859 cap_rights_t rights; 860 int i, n, nerrors, error; 861 862 cap_rights_init(&rights); 863 if (nchanges > 0) 864 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 865 if (nevents > 0) 866 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 867 error = fget(td, fd, &rights, &fp); 868 if (error != 0) 869 return (error); 870 871 error = kqueue_acquire(fp, &kq); 872 if (error != 0) 873 goto done_norel; 874 875 nerrors = 0; 876 877 while (nchanges > 0) { 878 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 879 error = k_ops->k_copyin(k_ops->arg, keva, n); 880 if (error) 881 goto done; 882 changes = keva; 883 for (i = 0; i < n; i++) { 884 kevp = &changes[i]; 885 if (!kevp->filter) 886 continue; 887 kevp->flags &= ~EV_SYSFLAGS; 888 error = kqueue_register(kq, kevp, td, 1); 889 if (error || (kevp->flags & EV_RECEIPT)) { 890 if (nevents != 0) { 891 kevp->flags = EV_ERROR; 892 kevp->data = error; 893 (void) k_ops->k_copyout(k_ops->arg, 894 kevp, 1); 895 nevents--; 896 nerrors++; 897 } else { 898 goto done; 899 } 900 } 901 } 902 nchanges -= n; 903 } 904 if (nerrors) { 905 td->td_retval[0] = nerrors; 906 error = 0; 907 goto done; 908 } 909 910 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 911 done: 912 kqueue_release(kq, 0); 913 done_norel: 914 fdrop(fp, td); 915 return (error); 916 } 917 918 int 919 kqueue_add_filteropts(int filt, struct filterops *filtops) 920 { 921 int error; 922 923 error = 0; 924 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 925 printf( 926 "trying to add a filterop that is out of range: %d is beyond %d\n", 927 ~filt, EVFILT_SYSCOUNT); 928 return EINVAL; 929 } 930 mtx_lock(&filterops_lock); 931 if (sysfilt_ops[~filt].for_fop != &null_filtops && 932 sysfilt_ops[~filt].for_fop != NULL) 933 error = EEXIST; 934 else { 935 sysfilt_ops[~filt].for_fop = filtops; 936 sysfilt_ops[~filt].for_refcnt = 0; 937 } 938 mtx_unlock(&filterops_lock); 939 940 return (error); 941 } 942 943 int 944 kqueue_del_filteropts(int filt) 945 { 946 int error; 947 948 error = 0; 949 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 950 return EINVAL; 951 952 mtx_lock(&filterops_lock); 953 if (sysfilt_ops[~filt].for_fop == &null_filtops || 954 sysfilt_ops[~filt].for_fop == NULL) 955 error = EINVAL; 956 else if (sysfilt_ops[~filt].for_refcnt != 0) 957 error = EBUSY; 958 else { 959 sysfilt_ops[~filt].for_fop = &null_filtops; 960 sysfilt_ops[~filt].for_refcnt = 0; 961 } 962 mtx_unlock(&filterops_lock); 963 964 return error; 965 } 966 967 static struct filterops * 968 kqueue_fo_find(int filt) 969 { 970 971 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 972 return NULL; 973 974 mtx_lock(&filterops_lock); 975 sysfilt_ops[~filt].for_refcnt++; 976 if (sysfilt_ops[~filt].for_fop == NULL) 977 sysfilt_ops[~filt].for_fop = &null_filtops; 978 mtx_unlock(&filterops_lock); 979 980 return sysfilt_ops[~filt].for_fop; 981 } 982 983 static void 984 kqueue_fo_release(int filt) 985 { 986 987 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 988 return; 989 990 mtx_lock(&filterops_lock); 991 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 992 ("filter object refcount not valid on release")); 993 sysfilt_ops[~filt].for_refcnt--; 994 mtx_unlock(&filterops_lock); 995 } 996 997 /* 998 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 999 * influence if memory allocation should wait. Make sure it is 0 if you 1000 * hold any mutexes. 1001 */ 1002 static int 1003 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1004 { 1005 struct filterops *fops; 1006 struct file *fp; 1007 struct knote *kn, *tkn; 1008 cap_rights_t rights; 1009 int error, filt, event; 1010 int haskqglobal, filedesc_unlock; 1011 1012 fp = NULL; 1013 kn = NULL; 1014 error = 0; 1015 haskqglobal = 0; 1016 filedesc_unlock = 0; 1017 1018 filt = kev->filter; 1019 fops = kqueue_fo_find(filt); 1020 if (fops == NULL) 1021 return EINVAL; 1022 1023 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1024 1025 findkn: 1026 if (fops->f_isfd) { 1027 KASSERT(td != NULL, ("td is NULL")); 1028 error = fget(td, kev->ident, 1029 cap_rights_init(&rights, CAP_EVENT), &fp); 1030 if (error) 1031 goto done; 1032 1033 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1034 kev->ident, 0) != 0) { 1035 /* try again */ 1036 fdrop(fp, td); 1037 fp = NULL; 1038 error = kqueue_expand(kq, fops, kev->ident, waitok); 1039 if (error) 1040 goto done; 1041 goto findkn; 1042 } 1043 1044 if (fp->f_type == DTYPE_KQUEUE) { 1045 /* 1046 * if we add some inteligence about what we are doing, 1047 * we should be able to support events on ourselves. 1048 * We need to know when we are doing this to prevent 1049 * getting both the knlist lock and the kq lock since 1050 * they are the same thing. 1051 */ 1052 if (fp->f_data == kq) { 1053 error = EINVAL; 1054 goto done; 1055 } 1056 1057 /* 1058 * Pre-lock the filedesc before the global 1059 * lock mutex, see the comment in 1060 * kqueue_close(). 1061 */ 1062 FILEDESC_XLOCK(td->td_proc->p_fd); 1063 filedesc_unlock = 1; 1064 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1065 } 1066 1067 KQ_LOCK(kq); 1068 if (kev->ident < kq->kq_knlistsize) { 1069 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1070 if (kev->filter == kn->kn_filter) 1071 break; 1072 } 1073 } else { 1074 if ((kev->flags & EV_ADD) == EV_ADD) 1075 kqueue_expand(kq, fops, kev->ident, waitok); 1076 1077 KQ_LOCK(kq); 1078 if (kq->kq_knhashmask != 0) { 1079 struct klist *list; 1080 1081 list = &kq->kq_knhash[ 1082 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1083 SLIST_FOREACH(kn, list, kn_link) 1084 if (kev->ident == kn->kn_id && 1085 kev->filter == kn->kn_filter) 1086 break; 1087 } 1088 } 1089 1090 /* knote is in the process of changing, wait for it to stablize. */ 1091 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1092 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1093 if (filedesc_unlock) { 1094 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1095 filedesc_unlock = 0; 1096 } 1097 kq->kq_state |= KQ_FLUXWAIT; 1098 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1099 if (fp != NULL) { 1100 fdrop(fp, td); 1101 fp = NULL; 1102 } 1103 goto findkn; 1104 } 1105 1106 /* 1107 * kn now contains the matching knote, or NULL if no match 1108 */ 1109 if (kn == NULL) { 1110 if (kev->flags & EV_ADD) { 1111 kn = tkn; 1112 tkn = NULL; 1113 if (kn == NULL) { 1114 KQ_UNLOCK(kq); 1115 error = ENOMEM; 1116 goto done; 1117 } 1118 kn->kn_fp = fp; 1119 kn->kn_kq = kq; 1120 kn->kn_fop = fops; 1121 /* 1122 * apply reference counts to knote structure, and 1123 * do not release it at the end of this routine. 1124 */ 1125 fops = NULL; 1126 fp = NULL; 1127 1128 kn->kn_sfflags = kev->fflags; 1129 kn->kn_sdata = kev->data; 1130 kev->fflags = 0; 1131 kev->data = 0; 1132 kn->kn_kevent = *kev; 1133 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1134 EV_ENABLE | EV_DISABLE); 1135 kn->kn_status = KN_INFLUX|KN_DETACHED; 1136 1137 error = knote_attach(kn, kq); 1138 KQ_UNLOCK(kq); 1139 if (error != 0) { 1140 tkn = kn; 1141 goto done; 1142 } 1143 1144 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1145 knote_drop(kn, td); 1146 goto done; 1147 } 1148 KN_LIST_LOCK(kn); 1149 goto done_ev_add; 1150 } else { 1151 /* No matching knote and the EV_ADD flag is not set. */ 1152 KQ_UNLOCK(kq); 1153 error = ENOENT; 1154 goto done; 1155 } 1156 } 1157 1158 if (kev->flags & EV_DELETE) { 1159 kn->kn_status |= KN_INFLUX; 1160 KQ_UNLOCK(kq); 1161 if (!(kn->kn_status & KN_DETACHED)) 1162 kn->kn_fop->f_detach(kn); 1163 knote_drop(kn, td); 1164 goto done; 1165 } 1166 1167 /* 1168 * The user may change some filter values after the initial EV_ADD, 1169 * but doing so will not reset any filter which has already been 1170 * triggered. 1171 */ 1172 kn->kn_status |= KN_INFLUX | KN_SCAN; 1173 KQ_UNLOCK(kq); 1174 KN_LIST_LOCK(kn); 1175 kn->kn_kevent.udata = kev->udata; 1176 if (!fops->f_isfd && fops->f_touch != NULL) { 1177 fops->f_touch(kn, kev, EVENT_REGISTER); 1178 } else { 1179 kn->kn_sfflags = kev->fflags; 1180 kn->kn_sdata = kev->data; 1181 } 1182 1183 /* 1184 * We can get here with kn->kn_knlist == NULL. This can happen when 1185 * the initial attach event decides that the event is "completed" 1186 * already. i.e. filt_procattach is called on a zombie process. It 1187 * will call filt_proc which will remove it from the list, and NULL 1188 * kn_knlist. 1189 */ 1190 done_ev_add: 1191 event = kn->kn_fop->f_event(kn, 0); 1192 KQ_LOCK(kq); 1193 if (event) 1194 KNOTE_ACTIVATE(kn, 1); 1195 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1196 KN_LIST_UNLOCK(kn); 1197 1198 if ((kev->flags & EV_DISABLE) && 1199 ((kn->kn_status & KN_DISABLED) == 0)) { 1200 kn->kn_status |= KN_DISABLED; 1201 } 1202 1203 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1204 kn->kn_status &= ~KN_DISABLED; 1205 if ((kn->kn_status & KN_ACTIVE) && 1206 ((kn->kn_status & KN_QUEUED) == 0)) 1207 knote_enqueue(kn); 1208 } 1209 KQ_UNLOCK_FLUX(kq); 1210 1211 done: 1212 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1213 if (filedesc_unlock) 1214 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1215 if (fp != NULL) 1216 fdrop(fp, td); 1217 if (tkn != NULL) 1218 knote_free(tkn); 1219 if (fops != NULL) 1220 kqueue_fo_release(filt); 1221 return (error); 1222 } 1223 1224 static int 1225 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1226 { 1227 int error; 1228 struct kqueue *kq; 1229 1230 error = 0; 1231 1232 kq = fp->f_data; 1233 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1234 return (EBADF); 1235 *kqp = kq; 1236 KQ_LOCK(kq); 1237 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1238 KQ_UNLOCK(kq); 1239 return (EBADF); 1240 } 1241 kq->kq_refcnt++; 1242 KQ_UNLOCK(kq); 1243 1244 return error; 1245 } 1246 1247 static void 1248 kqueue_release(struct kqueue *kq, int locked) 1249 { 1250 if (locked) 1251 KQ_OWNED(kq); 1252 else 1253 KQ_LOCK(kq); 1254 kq->kq_refcnt--; 1255 if (kq->kq_refcnt == 1) 1256 wakeup(&kq->kq_refcnt); 1257 if (!locked) 1258 KQ_UNLOCK(kq); 1259 } 1260 1261 static void 1262 kqueue_schedtask(struct kqueue *kq) 1263 { 1264 1265 KQ_OWNED(kq); 1266 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1267 ("scheduling kqueue task while draining")); 1268 1269 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1270 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1271 kq->kq_state |= KQ_TASKSCHED; 1272 } 1273 } 1274 1275 /* 1276 * Expand the kq to make sure we have storage for fops/ident pair. 1277 * 1278 * Return 0 on success (or no work necessary), return errno on failure. 1279 * 1280 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1281 * If kqueue_register is called from a non-fd context, there usually/should 1282 * be no locks held. 1283 */ 1284 static int 1285 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1286 int waitok) 1287 { 1288 struct klist *list, *tmp_knhash, *to_free; 1289 u_long tmp_knhashmask; 1290 int size; 1291 int fd; 1292 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1293 1294 KQ_NOTOWNED(kq); 1295 1296 to_free = NULL; 1297 if (fops->f_isfd) { 1298 fd = ident; 1299 if (kq->kq_knlistsize <= fd) { 1300 size = kq->kq_knlistsize; 1301 while (size <= fd) 1302 size += KQEXTENT; 1303 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1304 if (list == NULL) 1305 return ENOMEM; 1306 KQ_LOCK(kq); 1307 if (kq->kq_knlistsize > fd) { 1308 to_free = list; 1309 list = NULL; 1310 } else { 1311 if (kq->kq_knlist != NULL) { 1312 bcopy(kq->kq_knlist, list, 1313 kq->kq_knlistsize * sizeof(*list)); 1314 to_free = kq->kq_knlist; 1315 kq->kq_knlist = NULL; 1316 } 1317 bzero((caddr_t)list + 1318 kq->kq_knlistsize * sizeof(*list), 1319 (size - kq->kq_knlistsize) * sizeof(*list)); 1320 kq->kq_knlistsize = size; 1321 kq->kq_knlist = list; 1322 } 1323 KQ_UNLOCK(kq); 1324 } 1325 } else { 1326 if (kq->kq_knhashmask == 0) { 1327 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1328 &tmp_knhashmask); 1329 if (tmp_knhash == NULL) 1330 return ENOMEM; 1331 KQ_LOCK(kq); 1332 if (kq->kq_knhashmask == 0) { 1333 kq->kq_knhash = tmp_knhash; 1334 kq->kq_knhashmask = tmp_knhashmask; 1335 } else { 1336 to_free = tmp_knhash; 1337 } 1338 KQ_UNLOCK(kq); 1339 } 1340 } 1341 free(to_free, M_KQUEUE); 1342 1343 KQ_NOTOWNED(kq); 1344 return 0; 1345 } 1346 1347 static void 1348 kqueue_task(void *arg, int pending) 1349 { 1350 struct kqueue *kq; 1351 int haskqglobal; 1352 1353 haskqglobal = 0; 1354 kq = arg; 1355 1356 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1357 KQ_LOCK(kq); 1358 1359 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1360 1361 kq->kq_state &= ~KQ_TASKSCHED; 1362 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1363 wakeup(&kq->kq_state); 1364 } 1365 KQ_UNLOCK(kq); 1366 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1367 } 1368 1369 /* 1370 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1371 * We treat KN_MARKER knotes as if they are INFLUX. 1372 */ 1373 static int 1374 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1375 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1376 { 1377 struct kevent *kevp; 1378 struct knote *kn, *marker; 1379 sbintime_t asbt, rsbt; 1380 int count, error, haskqglobal, influx, nkev, touch; 1381 1382 count = maxevents; 1383 nkev = 0; 1384 error = 0; 1385 haskqglobal = 0; 1386 1387 if (maxevents == 0) 1388 goto done_nl; 1389 1390 rsbt = 0; 1391 if (tsp != NULL) { 1392 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1393 tsp->tv_nsec >= 1000000000) { 1394 error = EINVAL; 1395 goto done_nl; 1396 } 1397 if (timespecisset(tsp)) { 1398 if (tsp->tv_sec <= INT32_MAX) { 1399 rsbt = tstosbt(*tsp); 1400 if (TIMESEL(&asbt, rsbt)) 1401 asbt += tc_tick_sbt; 1402 if (asbt <= SBT_MAX - rsbt) 1403 asbt += rsbt; 1404 else 1405 asbt = 0; 1406 rsbt >>= tc_precexp; 1407 } else 1408 asbt = 0; 1409 } else 1410 asbt = -1; 1411 } else 1412 asbt = 0; 1413 marker = knote_alloc(1); 1414 if (marker == NULL) { 1415 error = ENOMEM; 1416 goto done_nl; 1417 } 1418 marker->kn_status = KN_MARKER; 1419 KQ_LOCK(kq); 1420 1421 retry: 1422 kevp = keva; 1423 if (kq->kq_count == 0) { 1424 if (asbt == -1) { 1425 error = EWOULDBLOCK; 1426 } else { 1427 kq->kq_state |= KQ_SLEEP; 1428 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1429 "kqread", asbt, rsbt, C_ABSOLUTE); 1430 } 1431 if (error == 0) 1432 goto retry; 1433 /* don't restart after signals... */ 1434 if (error == ERESTART) 1435 error = EINTR; 1436 else if (error == EWOULDBLOCK) 1437 error = 0; 1438 goto done; 1439 } 1440 1441 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1442 influx = 0; 1443 while (count) { 1444 KQ_OWNED(kq); 1445 kn = TAILQ_FIRST(&kq->kq_head); 1446 1447 if ((kn->kn_status == KN_MARKER && kn != marker) || 1448 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1449 if (influx) { 1450 influx = 0; 1451 KQ_FLUX_WAKEUP(kq); 1452 } 1453 kq->kq_state |= KQ_FLUXWAIT; 1454 error = msleep(kq, &kq->kq_lock, PSOCK, 1455 "kqflxwt", 0); 1456 continue; 1457 } 1458 1459 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1460 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1461 kn->kn_status &= ~KN_QUEUED; 1462 kq->kq_count--; 1463 continue; 1464 } 1465 if (kn == marker) { 1466 KQ_FLUX_WAKEUP(kq); 1467 if (count == maxevents) 1468 goto retry; 1469 goto done; 1470 } 1471 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1472 ("KN_INFLUX set when not suppose to be")); 1473 1474 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1475 kn->kn_status &= ~KN_QUEUED; 1476 kn->kn_status |= KN_INFLUX; 1477 kq->kq_count--; 1478 KQ_UNLOCK(kq); 1479 /* 1480 * We don't need to lock the list since we've marked 1481 * it _INFLUX. 1482 */ 1483 if (!(kn->kn_status & KN_DETACHED)) 1484 kn->kn_fop->f_detach(kn); 1485 knote_drop(kn, td); 1486 KQ_LOCK(kq); 1487 continue; 1488 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1489 kn->kn_status &= ~KN_QUEUED; 1490 kn->kn_status |= KN_INFLUX; 1491 kq->kq_count--; 1492 KQ_UNLOCK(kq); 1493 /* 1494 * We don't need to lock the list since we've marked 1495 * it _INFLUX. 1496 */ 1497 *kevp = kn->kn_kevent; 1498 if (!(kn->kn_status & KN_DETACHED)) 1499 kn->kn_fop->f_detach(kn); 1500 knote_drop(kn, td); 1501 KQ_LOCK(kq); 1502 kn = NULL; 1503 } else { 1504 kn->kn_status |= KN_INFLUX | KN_SCAN; 1505 KQ_UNLOCK(kq); 1506 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1507 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1508 KN_LIST_LOCK(kn); 1509 if (kn->kn_fop->f_event(kn, 0) == 0) { 1510 KQ_LOCK(kq); 1511 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1512 kn->kn_status &= 1513 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX | 1514 KN_SCAN); 1515 kq->kq_count--; 1516 KN_LIST_UNLOCK(kn); 1517 influx = 1; 1518 continue; 1519 } 1520 touch = (!kn->kn_fop->f_isfd && 1521 kn->kn_fop->f_touch != NULL); 1522 if (touch) 1523 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1524 else 1525 *kevp = kn->kn_kevent; 1526 KQ_LOCK(kq); 1527 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1528 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1529 /* 1530 * Manually clear knotes who weren't 1531 * 'touch'ed. 1532 */ 1533 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1534 kn->kn_data = 0; 1535 kn->kn_fflags = 0; 1536 } 1537 if (kn->kn_flags & EV_DISPATCH) 1538 kn->kn_status |= KN_DISABLED; 1539 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1540 kq->kq_count--; 1541 } else 1542 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1543 1544 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1545 KN_LIST_UNLOCK(kn); 1546 influx = 1; 1547 } 1548 1549 /* we are returning a copy to the user */ 1550 kevp++; 1551 nkev++; 1552 count--; 1553 1554 if (nkev == KQ_NEVENTS) { 1555 influx = 0; 1556 KQ_UNLOCK_FLUX(kq); 1557 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1558 nkev = 0; 1559 kevp = keva; 1560 KQ_LOCK(kq); 1561 if (error) 1562 break; 1563 } 1564 } 1565 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1566 done: 1567 KQ_OWNED(kq); 1568 KQ_UNLOCK_FLUX(kq); 1569 knote_free(marker); 1570 done_nl: 1571 KQ_NOTOWNED(kq); 1572 if (nkev != 0) 1573 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1574 td->td_retval[0] = maxevents - count; 1575 return (error); 1576 } 1577 1578 /* 1579 * XXX 1580 * This could be expanded to call kqueue_scan, if desired. 1581 */ 1582 /*ARGSUSED*/ 1583 static int 1584 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1585 int flags, struct thread *td) 1586 { 1587 return (ENXIO); 1588 } 1589 1590 /*ARGSUSED*/ 1591 static int 1592 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1593 int flags, struct thread *td) 1594 { 1595 return (ENXIO); 1596 } 1597 1598 /*ARGSUSED*/ 1599 static int 1600 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1601 struct thread *td) 1602 { 1603 1604 return (EINVAL); 1605 } 1606 1607 /*ARGSUSED*/ 1608 static int 1609 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1610 struct ucred *active_cred, struct thread *td) 1611 { 1612 /* 1613 * Enabling sigio causes two major problems: 1614 * 1) infinite recursion: 1615 * Synopsys: kevent is being used to track signals and have FIOASYNC 1616 * set. On receipt of a signal this will cause a kqueue to recurse 1617 * into itself over and over. Sending the sigio causes the kqueue 1618 * to become ready, which in turn posts sigio again, forever. 1619 * Solution: this can be solved by setting a flag in the kqueue that 1620 * we have a SIGIO in progress. 1621 * 2) locking problems: 1622 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1623 * us above the proc and pgrp locks. 1624 * Solution: Post a signal using an async mechanism, being sure to 1625 * record a generation count in the delivery so that we do not deliver 1626 * a signal to the wrong process. 1627 * 1628 * Note, these two mechanisms are somewhat mutually exclusive! 1629 */ 1630 #if 0 1631 struct kqueue *kq; 1632 1633 kq = fp->f_data; 1634 switch (cmd) { 1635 case FIOASYNC: 1636 if (*(int *)data) { 1637 kq->kq_state |= KQ_ASYNC; 1638 } else { 1639 kq->kq_state &= ~KQ_ASYNC; 1640 } 1641 return (0); 1642 1643 case FIOSETOWN: 1644 return (fsetown(*(int *)data, &kq->kq_sigio)); 1645 1646 case FIOGETOWN: 1647 *(int *)data = fgetown(&kq->kq_sigio); 1648 return (0); 1649 } 1650 #endif 1651 1652 return (ENOTTY); 1653 } 1654 1655 /*ARGSUSED*/ 1656 static int 1657 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1658 struct thread *td) 1659 { 1660 struct kqueue *kq; 1661 int revents = 0; 1662 int error; 1663 1664 if ((error = kqueue_acquire(fp, &kq))) 1665 return POLLERR; 1666 1667 KQ_LOCK(kq); 1668 if (events & (POLLIN | POLLRDNORM)) { 1669 if (kq->kq_count) { 1670 revents |= events & (POLLIN | POLLRDNORM); 1671 } else { 1672 selrecord(td, &kq->kq_sel); 1673 if (SEL_WAITING(&kq->kq_sel)) 1674 kq->kq_state |= KQ_SEL; 1675 } 1676 } 1677 kqueue_release(kq, 1); 1678 KQ_UNLOCK(kq); 1679 return (revents); 1680 } 1681 1682 /*ARGSUSED*/ 1683 static int 1684 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1685 struct thread *td) 1686 { 1687 1688 bzero((void *)st, sizeof *st); 1689 /* 1690 * We no longer return kq_count because the unlocked value is useless. 1691 * If you spent all this time getting the count, why not spend your 1692 * syscall better by calling kevent? 1693 * 1694 * XXX - This is needed for libc_r. 1695 */ 1696 st->st_mode = S_IFIFO; 1697 return (0); 1698 } 1699 1700 /*ARGSUSED*/ 1701 static int 1702 kqueue_close(struct file *fp, struct thread *td) 1703 { 1704 struct kqueue *kq = fp->f_data; 1705 struct filedesc *fdp; 1706 struct knote *kn; 1707 int i; 1708 int error; 1709 int filedesc_unlock; 1710 1711 if ((error = kqueue_acquire(fp, &kq))) 1712 return error; 1713 1714 filedesc_unlock = 0; 1715 KQ_LOCK(kq); 1716 1717 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1718 ("kqueue already closing")); 1719 kq->kq_state |= KQ_CLOSING; 1720 if (kq->kq_refcnt > 1) 1721 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1722 1723 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1724 fdp = kq->kq_fdp; 1725 1726 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1727 ("kqueue's knlist not empty")); 1728 1729 for (i = 0; i < kq->kq_knlistsize; i++) { 1730 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1731 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1732 kq->kq_state |= KQ_FLUXWAIT; 1733 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1734 continue; 1735 } 1736 kn->kn_status |= KN_INFLUX; 1737 KQ_UNLOCK(kq); 1738 if (!(kn->kn_status & KN_DETACHED)) 1739 kn->kn_fop->f_detach(kn); 1740 knote_drop(kn, td); 1741 KQ_LOCK(kq); 1742 } 1743 } 1744 if (kq->kq_knhashmask != 0) { 1745 for (i = 0; i <= kq->kq_knhashmask; i++) { 1746 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1747 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1748 kq->kq_state |= KQ_FLUXWAIT; 1749 msleep(kq, &kq->kq_lock, PSOCK, 1750 "kqclo2", 0); 1751 continue; 1752 } 1753 kn->kn_status |= KN_INFLUX; 1754 KQ_UNLOCK(kq); 1755 if (!(kn->kn_status & KN_DETACHED)) 1756 kn->kn_fop->f_detach(kn); 1757 knote_drop(kn, td); 1758 KQ_LOCK(kq); 1759 } 1760 } 1761 } 1762 1763 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1764 kq->kq_state |= KQ_TASKDRAIN; 1765 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1766 } 1767 1768 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1769 selwakeuppri(&kq->kq_sel, PSOCK); 1770 if (!SEL_WAITING(&kq->kq_sel)) 1771 kq->kq_state &= ~KQ_SEL; 1772 } 1773 1774 KQ_UNLOCK(kq); 1775 1776 /* 1777 * We could be called due to the knote_drop() doing fdrop(), 1778 * called from kqueue_register(). In this case the global 1779 * lock is owned, and filedesc sx is locked before, to not 1780 * take the sleepable lock after non-sleepable. 1781 */ 1782 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1783 FILEDESC_XLOCK(fdp); 1784 filedesc_unlock = 1; 1785 } else 1786 filedesc_unlock = 0; 1787 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1788 if (filedesc_unlock) 1789 FILEDESC_XUNLOCK(fdp); 1790 1791 seldrain(&kq->kq_sel); 1792 knlist_destroy(&kq->kq_sel.si_note); 1793 mtx_destroy(&kq->kq_lock); 1794 kq->kq_fdp = NULL; 1795 1796 if (kq->kq_knhash != NULL) 1797 free(kq->kq_knhash, M_KQUEUE); 1798 if (kq->kq_knlist != NULL) 1799 free(kq->kq_knlist, M_KQUEUE); 1800 1801 funsetown(&kq->kq_sigio); 1802 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 1803 crfree(kq->kq_cred); 1804 free(kq, M_KQUEUE); 1805 fp->f_data = NULL; 1806 1807 return (0); 1808 } 1809 1810 static void 1811 kqueue_wakeup(struct kqueue *kq) 1812 { 1813 KQ_OWNED(kq); 1814 1815 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1816 kq->kq_state &= ~KQ_SLEEP; 1817 wakeup(kq); 1818 } 1819 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1820 selwakeuppri(&kq->kq_sel, PSOCK); 1821 if (!SEL_WAITING(&kq->kq_sel)) 1822 kq->kq_state &= ~KQ_SEL; 1823 } 1824 if (!knlist_empty(&kq->kq_sel.si_note)) 1825 kqueue_schedtask(kq); 1826 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1827 pgsigio(&kq->kq_sigio, SIGIO, 0); 1828 } 1829 } 1830 1831 /* 1832 * Walk down a list of knotes, activating them if their event has triggered. 1833 * 1834 * There is a possibility to optimize in the case of one kq watching another. 1835 * Instead of scheduling a task to wake it up, you could pass enough state 1836 * down the chain to make up the parent kqueue. Make this code functional 1837 * first. 1838 */ 1839 void 1840 knote(struct knlist *list, long hint, int lockflags) 1841 { 1842 struct kqueue *kq; 1843 struct knote *kn; 1844 int error; 1845 1846 if (list == NULL) 1847 return; 1848 1849 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1850 1851 if ((lockflags & KNF_LISTLOCKED) == 0) 1852 list->kl_lock(list->kl_lockarg); 1853 1854 /* 1855 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1856 * the kqueue scheduling, but this will introduce four 1857 * lock/unlock's for each knote to test. If we do, continue to use 1858 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1859 * only safe if you want to remove the current item, which we are 1860 * not doing. 1861 */ 1862 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1863 kq = kn->kn_kq; 1864 KQ_LOCK(kq); 1865 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 1866 /* 1867 * Do not process the influx notes, except for 1868 * the influx coming from the kq unlock in the 1869 * kqueue_scan(). In the later case, we do 1870 * not interfere with the scan, since the code 1871 * fragment in kqueue_scan() locks the knlist, 1872 * and cannot proceed until we finished. 1873 */ 1874 KQ_UNLOCK(kq); 1875 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1876 kn->kn_status |= KN_INFLUX; 1877 KQ_UNLOCK(kq); 1878 error = kn->kn_fop->f_event(kn, hint); 1879 KQ_LOCK(kq); 1880 kn->kn_status &= ~KN_INFLUX; 1881 if (error) 1882 KNOTE_ACTIVATE(kn, 1); 1883 KQ_UNLOCK_FLUX(kq); 1884 } else { 1885 kn->kn_status |= KN_HASKQLOCK; 1886 if (kn->kn_fop->f_event(kn, hint)) 1887 KNOTE_ACTIVATE(kn, 1); 1888 kn->kn_status &= ~KN_HASKQLOCK; 1889 KQ_UNLOCK(kq); 1890 } 1891 } 1892 if ((lockflags & KNF_LISTLOCKED) == 0) 1893 list->kl_unlock(list->kl_lockarg); 1894 } 1895 1896 /* 1897 * add a knote to a knlist 1898 */ 1899 void 1900 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1901 { 1902 KNL_ASSERT_LOCK(knl, islocked); 1903 KQ_NOTOWNED(kn->kn_kq); 1904 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1905 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1906 if (!islocked) 1907 knl->kl_lock(knl->kl_lockarg); 1908 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1909 if (!islocked) 1910 knl->kl_unlock(knl->kl_lockarg); 1911 KQ_LOCK(kn->kn_kq); 1912 kn->kn_knlist = knl; 1913 kn->kn_status &= ~KN_DETACHED; 1914 KQ_UNLOCK(kn->kn_kq); 1915 } 1916 1917 static void 1918 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1919 { 1920 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1921 KNL_ASSERT_LOCK(knl, knlislocked); 1922 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1923 if (!kqislocked) 1924 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1925 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1926 if (!knlislocked) 1927 knl->kl_lock(knl->kl_lockarg); 1928 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1929 kn->kn_knlist = NULL; 1930 if (!knlislocked) 1931 knl->kl_unlock(knl->kl_lockarg); 1932 if (!kqislocked) 1933 KQ_LOCK(kn->kn_kq); 1934 kn->kn_status |= KN_DETACHED; 1935 if (!kqislocked) 1936 KQ_UNLOCK(kn->kn_kq); 1937 } 1938 1939 /* 1940 * remove knote from the specified knlist 1941 */ 1942 void 1943 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1944 { 1945 1946 knlist_remove_kq(knl, kn, islocked, 0); 1947 } 1948 1949 /* 1950 * remove knote from the specified knlist while in f_event handler. 1951 */ 1952 void 1953 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1954 { 1955 1956 knlist_remove_kq(knl, kn, 1, 1957 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1958 } 1959 1960 int 1961 knlist_empty(struct knlist *knl) 1962 { 1963 1964 KNL_ASSERT_LOCKED(knl); 1965 return SLIST_EMPTY(&knl->kl_list); 1966 } 1967 1968 static struct mtx knlist_lock; 1969 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1970 MTX_DEF); 1971 static void knlist_mtx_lock(void *arg); 1972 static void knlist_mtx_unlock(void *arg); 1973 1974 static void 1975 knlist_mtx_lock(void *arg) 1976 { 1977 1978 mtx_lock((struct mtx *)arg); 1979 } 1980 1981 static void 1982 knlist_mtx_unlock(void *arg) 1983 { 1984 1985 mtx_unlock((struct mtx *)arg); 1986 } 1987 1988 static void 1989 knlist_mtx_assert_locked(void *arg) 1990 { 1991 1992 mtx_assert((struct mtx *)arg, MA_OWNED); 1993 } 1994 1995 static void 1996 knlist_mtx_assert_unlocked(void *arg) 1997 { 1998 1999 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2000 } 2001 2002 static void 2003 knlist_rw_rlock(void *arg) 2004 { 2005 2006 rw_rlock((struct rwlock *)arg); 2007 } 2008 2009 static void 2010 knlist_rw_runlock(void *arg) 2011 { 2012 2013 rw_runlock((struct rwlock *)arg); 2014 } 2015 2016 static void 2017 knlist_rw_assert_locked(void *arg) 2018 { 2019 2020 rw_assert((struct rwlock *)arg, RA_LOCKED); 2021 } 2022 2023 static void 2024 knlist_rw_assert_unlocked(void *arg) 2025 { 2026 2027 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2028 } 2029 2030 void 2031 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2032 void (*kl_unlock)(void *), 2033 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2034 { 2035 2036 if (lock == NULL) 2037 knl->kl_lockarg = &knlist_lock; 2038 else 2039 knl->kl_lockarg = lock; 2040 2041 if (kl_lock == NULL) 2042 knl->kl_lock = knlist_mtx_lock; 2043 else 2044 knl->kl_lock = kl_lock; 2045 if (kl_unlock == NULL) 2046 knl->kl_unlock = knlist_mtx_unlock; 2047 else 2048 knl->kl_unlock = kl_unlock; 2049 if (kl_assert_locked == NULL) 2050 knl->kl_assert_locked = knlist_mtx_assert_locked; 2051 else 2052 knl->kl_assert_locked = kl_assert_locked; 2053 if (kl_assert_unlocked == NULL) 2054 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2055 else 2056 knl->kl_assert_unlocked = kl_assert_unlocked; 2057 2058 SLIST_INIT(&knl->kl_list); 2059 } 2060 2061 void 2062 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2063 { 2064 2065 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2066 } 2067 2068 void 2069 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2070 { 2071 2072 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2073 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2074 } 2075 2076 void 2077 knlist_destroy(struct knlist *knl) 2078 { 2079 2080 #ifdef INVARIANTS 2081 /* 2082 * if we run across this error, we need to find the offending 2083 * driver and have it call knlist_clear or knlist_delete. 2084 */ 2085 if (!SLIST_EMPTY(&knl->kl_list)) 2086 printf("WARNING: destroying knlist w/ knotes on it!\n"); 2087 #endif 2088 2089 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 2090 SLIST_INIT(&knl->kl_list); 2091 } 2092 2093 /* 2094 * Even if we are locked, we may need to drop the lock to allow any influx 2095 * knotes time to "settle". 2096 */ 2097 void 2098 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2099 { 2100 struct knote *kn, *kn2; 2101 struct kqueue *kq; 2102 2103 if (islocked) 2104 KNL_ASSERT_LOCKED(knl); 2105 else { 2106 KNL_ASSERT_UNLOCKED(knl); 2107 again: /* need to reacquire lock since we have dropped it */ 2108 knl->kl_lock(knl->kl_lockarg); 2109 } 2110 2111 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2112 kq = kn->kn_kq; 2113 KQ_LOCK(kq); 2114 if ((kn->kn_status & KN_INFLUX)) { 2115 KQ_UNLOCK(kq); 2116 continue; 2117 } 2118 knlist_remove_kq(knl, kn, 1, 1); 2119 if (killkn) { 2120 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2121 KQ_UNLOCK(kq); 2122 knote_drop(kn, td); 2123 } else { 2124 /* Make sure cleared knotes disappear soon */ 2125 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2126 KQ_UNLOCK(kq); 2127 } 2128 kq = NULL; 2129 } 2130 2131 if (!SLIST_EMPTY(&knl->kl_list)) { 2132 /* there are still KN_INFLUX remaining */ 2133 kn = SLIST_FIRST(&knl->kl_list); 2134 kq = kn->kn_kq; 2135 KQ_LOCK(kq); 2136 KASSERT(kn->kn_status & KN_INFLUX, 2137 ("knote removed w/o list lock")); 2138 knl->kl_unlock(knl->kl_lockarg); 2139 kq->kq_state |= KQ_FLUXWAIT; 2140 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2141 kq = NULL; 2142 goto again; 2143 } 2144 2145 if (islocked) 2146 KNL_ASSERT_LOCKED(knl); 2147 else { 2148 knl->kl_unlock(knl->kl_lockarg); 2149 KNL_ASSERT_UNLOCKED(knl); 2150 } 2151 } 2152 2153 /* 2154 * Remove all knotes referencing a specified fd must be called with FILEDESC 2155 * lock. This prevents a race where a new fd comes along and occupies the 2156 * entry and we attach a knote to the fd. 2157 */ 2158 void 2159 knote_fdclose(struct thread *td, int fd) 2160 { 2161 struct filedesc *fdp = td->td_proc->p_fd; 2162 struct kqueue *kq; 2163 struct knote *kn; 2164 int influx; 2165 2166 FILEDESC_XLOCK_ASSERT(fdp); 2167 2168 /* 2169 * We shouldn't have to worry about new kevents appearing on fd 2170 * since filedesc is locked. 2171 */ 2172 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2173 KQ_LOCK(kq); 2174 2175 again: 2176 influx = 0; 2177 while (kq->kq_knlistsize > fd && 2178 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2179 if (kn->kn_status & KN_INFLUX) { 2180 /* someone else might be waiting on our knote */ 2181 if (influx) 2182 wakeup(kq); 2183 kq->kq_state |= KQ_FLUXWAIT; 2184 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2185 goto again; 2186 } 2187 kn->kn_status |= KN_INFLUX; 2188 KQ_UNLOCK(kq); 2189 if (!(kn->kn_status & KN_DETACHED)) 2190 kn->kn_fop->f_detach(kn); 2191 knote_drop(kn, td); 2192 influx = 1; 2193 KQ_LOCK(kq); 2194 } 2195 KQ_UNLOCK_FLUX(kq); 2196 } 2197 } 2198 2199 static int 2200 knote_attach(struct knote *kn, struct kqueue *kq) 2201 { 2202 struct klist *list; 2203 2204 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2205 KQ_OWNED(kq); 2206 2207 if (kn->kn_fop->f_isfd) { 2208 if (kn->kn_id >= kq->kq_knlistsize) 2209 return ENOMEM; 2210 list = &kq->kq_knlist[kn->kn_id]; 2211 } else { 2212 if (kq->kq_knhash == NULL) 2213 return ENOMEM; 2214 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2215 } 2216 2217 SLIST_INSERT_HEAD(list, kn, kn_link); 2218 2219 return 0; 2220 } 2221 2222 /* 2223 * knote must already have been detached using the f_detach method. 2224 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2225 * to prevent other removal. 2226 */ 2227 static void 2228 knote_drop(struct knote *kn, struct thread *td) 2229 { 2230 struct kqueue *kq; 2231 struct klist *list; 2232 2233 kq = kn->kn_kq; 2234 2235 KQ_NOTOWNED(kq); 2236 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2237 ("knote_drop called without KN_INFLUX set in kn_status")); 2238 2239 KQ_LOCK(kq); 2240 if (kn->kn_fop->f_isfd) 2241 list = &kq->kq_knlist[kn->kn_id]; 2242 else 2243 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2244 2245 if (!SLIST_EMPTY(list)) 2246 SLIST_REMOVE(list, kn, knote, kn_link); 2247 if (kn->kn_status & KN_QUEUED) 2248 knote_dequeue(kn); 2249 KQ_UNLOCK_FLUX(kq); 2250 2251 if (kn->kn_fop->f_isfd) { 2252 fdrop(kn->kn_fp, td); 2253 kn->kn_fp = NULL; 2254 } 2255 kqueue_fo_release(kn->kn_kevent.filter); 2256 kn->kn_fop = NULL; 2257 knote_free(kn); 2258 } 2259 2260 static void 2261 knote_enqueue(struct knote *kn) 2262 { 2263 struct kqueue *kq = kn->kn_kq; 2264 2265 KQ_OWNED(kn->kn_kq); 2266 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2267 2268 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2269 kn->kn_status |= KN_QUEUED; 2270 kq->kq_count++; 2271 kqueue_wakeup(kq); 2272 } 2273 2274 static void 2275 knote_dequeue(struct knote *kn) 2276 { 2277 struct kqueue *kq = kn->kn_kq; 2278 2279 KQ_OWNED(kn->kn_kq); 2280 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2281 2282 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2283 kn->kn_status &= ~KN_QUEUED; 2284 kq->kq_count--; 2285 } 2286 2287 static void 2288 knote_init(void) 2289 { 2290 2291 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2292 NULL, NULL, UMA_ALIGN_PTR, 0); 2293 } 2294 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2295 2296 static struct knote * 2297 knote_alloc(int waitok) 2298 { 2299 return ((struct knote *)uma_zalloc(knote_zone, 2300 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2301 } 2302 2303 static void 2304 knote_free(struct knote *kn) 2305 { 2306 if (kn != NULL) 2307 uma_zfree(knote_zone, kn); 2308 } 2309 2310 /* 2311 * Register the kev w/ the kq specified by fd. 2312 */ 2313 int 2314 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2315 { 2316 struct kqueue *kq; 2317 struct file *fp; 2318 cap_rights_t rights; 2319 int error; 2320 2321 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2322 if (error != 0) 2323 return (error); 2324 if ((error = kqueue_acquire(fp, &kq)) != 0) 2325 goto noacquire; 2326 2327 error = kqueue_register(kq, kev, td, waitok); 2328 2329 kqueue_release(kq, 0); 2330 2331 noacquire: 2332 fdrop(fp, td); 2333 2334 return error; 2335 } 2336