1 /*- 2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/sys/kern/kern_event.c,v 1.2.2.10 2004/04/04 07:03:14 cperciva Exp $ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/systm.h> 31 #include <sys/kernel.h> 32 #include <sys/proc.h> 33 #include <sys/malloc.h> 34 #include <sys/unistd.h> 35 #include <sys/file.h> 36 #include <sys/lock.h> 37 #include <sys/fcntl.h> 38 #include <sys/queue.h> 39 #include <sys/event.h> 40 #include <sys/eventvar.h> 41 #include <sys/protosw.h> 42 #include <sys/socket.h> 43 #include <sys/socketvar.h> 44 #include <sys/stat.h> 45 #include <sys/sysctl.h> 46 #include <sys/sysproto.h> 47 #include <sys/thread.h> 48 #include <sys/uio.h> 49 #include <sys/signalvar.h> 50 #include <sys/filio.h> 51 #include <sys/ktr.h> 52 53 #include <sys/thread2.h> 54 #include <sys/file2.h> 55 #include <sys/mplock2.h> 56 57 #define EVENT_REGISTER 1 58 #define EVENT_PROCESS 2 59 60 MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 61 62 struct kevent_copyin_args { 63 struct kevent_args *ka; 64 int pchanges; 65 }; 66 67 static int kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, 68 struct knote *marker); 69 static int kqueue_read(struct file *fp, struct uio *uio, 70 struct ucred *cred, int flags); 71 static int kqueue_write(struct file *fp, struct uio *uio, 72 struct ucred *cred, int flags); 73 static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data, 74 struct ucred *cred, struct sysmsg *msg); 75 static int kqueue_kqfilter(struct file *fp, struct knote *kn); 76 static int kqueue_stat(struct file *fp, struct stat *st, 77 struct ucred *cred); 78 static int kqueue_close(struct file *fp); 79 static void kqueue_wakeup(struct kqueue *kq); 80 static int filter_attach(struct knote *kn); 81 static int filter_event(struct knote *kn, long hint); 82 83 /* 84 * MPSAFE 85 */ 86 static struct fileops kqueueops = { 87 .fo_read = kqueue_read, 88 .fo_write = kqueue_write, 89 .fo_ioctl = kqueue_ioctl, 90 .fo_kqfilter = kqueue_kqfilter, 91 .fo_stat = kqueue_stat, 92 .fo_close = kqueue_close, 93 .fo_shutdown = nofo_shutdown 94 }; 95 96 static void knote_attach(struct knote *kn); 97 static void knote_drop(struct knote *kn); 98 static void knote_detach_and_drop(struct knote *kn); 99 static void knote_enqueue(struct knote *kn); 100 static void knote_dequeue(struct knote *kn); 101 static struct knote *knote_alloc(void); 102 static void knote_free(struct knote *kn); 103 104 static void filt_kqdetach(struct knote *kn); 105 static int filt_kqueue(struct knote *kn, long hint); 106 static int filt_procattach(struct knote *kn); 107 static void filt_procdetach(struct knote *kn); 108 static int filt_proc(struct knote *kn, long hint); 109 static int filt_fileattach(struct knote *kn); 110 static void filt_timerexpire(void *knx); 111 static int filt_timerattach(struct knote *kn); 112 static void filt_timerdetach(struct knote *kn); 113 static int filt_timer(struct knote *kn, long hint); 114 static int filt_userattach(struct knote *kn); 115 static void filt_userdetach(struct knote *kn); 116 static int filt_user(struct knote *kn, long hint); 117 static void filt_usertouch(struct knote *kn, struct kevent *kev, 118 u_long type); 119 120 static struct filterops file_filtops = 121 { FILTEROP_ISFD | FILTEROP_MPSAFE, filt_fileattach, NULL, NULL }; 122 static struct filterops kqread_filtops = 123 { FILTEROP_ISFD | FILTEROP_MPSAFE, NULL, filt_kqdetach, filt_kqueue }; 124 static struct filterops proc_filtops = 125 { 0, filt_procattach, filt_procdetach, filt_proc }; 126 static struct filterops timer_filtops = 127 { FILTEROP_MPSAFE, filt_timerattach, filt_timerdetach, filt_timer }; 128 static struct filterops user_filtops = 129 { FILTEROP_MPSAFE, filt_userattach, filt_userdetach, filt_user }; 130 131 static int kq_ncallouts = 0; 132 static int kq_calloutmax = (4 * 1024); 133 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 134 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 135 static int kq_checkloop = 1000000; 136 SYSCTL_INT(_kern, OID_AUTO, kq_checkloop, CTLFLAG_RW, 137 &kq_checkloop, 0, "Maximum number of loops for kqueue scan"); 138 static int kq_wakeup_one = 1; 139 SYSCTL_INT(_kern, OID_AUTO, kq_wakeup_one, CTLFLAG_RW, 140 &kq_wakeup_one, 0, "Wakeup only one kqueue scanner"); 141 142 #define KNOTE_ACTIVATE(kn) do { \ 143 kn->kn_status |= KN_ACTIVE; \ 144 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 145 knote_enqueue(kn); \ 146 } while(0) 147 148 #define KN_HASHSIZE 64 /* XXX should be tunable */ 149 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 150 151 extern struct filterops aio_filtops; 152 extern struct filterops sig_filtops; 153 154 /* 155 * Table for for all system-defined filters. 156 */ 157 static struct filterops *sysfilt_ops[] = { 158 &file_filtops, /* EVFILT_READ */ 159 &file_filtops, /* EVFILT_WRITE */ 160 &aio_filtops, /* EVFILT_AIO */ 161 &file_filtops, /* EVFILT_VNODE */ 162 &proc_filtops, /* EVFILT_PROC */ 163 &sig_filtops, /* EVFILT_SIGNAL */ 164 &timer_filtops, /* EVFILT_TIMER */ 165 &file_filtops, /* EVFILT_EXCEPT */ 166 &user_filtops, /* EVFILT_USER */ 167 }; 168 169 /* 170 * Acquire a knote, return non-zero on success, 0 on failure. 171 * 172 * If we cannot acquire the knote we sleep and return 0. The knote 173 * may be stale on return in this case and the caller must restart 174 * whatever loop they are in. 175 * 176 * Related kq token must be held. 177 */ 178 static __inline int 179 knote_acquire(struct knote *kn) 180 { 181 if (kn->kn_status & KN_PROCESSING) { 182 kn->kn_status |= KN_WAITING | KN_REPROCESS; 183 tsleep(kn, 0, "kqepts", hz); 184 /* knote may be stale now */ 185 return(0); 186 } 187 kn->kn_status |= KN_PROCESSING; 188 return(1); 189 } 190 191 /* 192 * Release an acquired knote, clearing KN_PROCESSING and handling any 193 * KN_REPROCESS events. 194 * 195 * Caller must be holding the related kq token 196 * 197 * Non-zero is returned if the knote is destroyed or detached. 198 */ 199 static __inline int 200 knote_release(struct knote *kn) 201 { 202 while (kn->kn_status & KN_REPROCESS) { 203 kn->kn_status &= ~KN_REPROCESS; 204 if (kn->kn_status & KN_WAITING) { 205 kn->kn_status &= ~KN_WAITING; 206 wakeup(kn); 207 } 208 if (kn->kn_status & KN_DELETING) { 209 knote_detach_and_drop(kn); 210 return(1); 211 /* NOT REACHED */ 212 } 213 if (filter_event(kn, 0)) 214 KNOTE_ACTIVATE(kn); 215 } 216 kn->kn_status &= ~KN_PROCESSING; 217 if (kn->kn_status & KN_DETACHED) 218 return(1); 219 else 220 return(0); 221 } 222 223 static int 224 filt_fileattach(struct knote *kn) 225 { 226 return (fo_kqfilter(kn->kn_fp, kn)); 227 } 228 229 /* 230 * MPSAFE 231 */ 232 static int 233 kqueue_kqfilter(struct file *fp, struct knote *kn) 234 { 235 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 236 237 if (kn->kn_filter != EVFILT_READ) 238 return (EOPNOTSUPP); 239 240 kn->kn_fop = &kqread_filtops; 241 knote_insert(&kq->kq_kqinfo.ki_note, kn); 242 return (0); 243 } 244 245 static void 246 filt_kqdetach(struct knote *kn) 247 { 248 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 249 250 knote_remove(&kq->kq_kqinfo.ki_note, kn); 251 } 252 253 /*ARGSUSED*/ 254 static int 255 filt_kqueue(struct knote *kn, long hint) 256 { 257 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 258 259 kn->kn_data = kq->kq_count; 260 return (kn->kn_data > 0); 261 } 262 263 static int 264 filt_procattach(struct knote *kn) 265 { 266 struct proc *p; 267 int immediate; 268 269 immediate = 0; 270 p = pfind(kn->kn_id); 271 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 272 p = zpfind(kn->kn_id); 273 immediate = 1; 274 } 275 if (p == NULL) { 276 return (ESRCH); 277 } 278 if (!PRISON_CHECK(curthread->td_ucred, p->p_ucred)) { 279 if (p) 280 PRELE(p); 281 return (EACCES); 282 } 283 284 lwkt_gettoken(&p->p_token); 285 kn->kn_ptr.p_proc = p; 286 kn->kn_flags |= EV_CLEAR; /* automatically set */ 287 288 /* 289 * internal flag indicating registration done by kernel 290 */ 291 if (kn->kn_flags & EV_FLAG1) { 292 kn->kn_data = kn->kn_sdata; /* ppid */ 293 kn->kn_fflags = NOTE_CHILD; 294 kn->kn_flags &= ~EV_FLAG1; 295 } 296 297 knote_insert(&p->p_klist, kn); 298 299 /* 300 * Immediately activate any exit notes if the target process is a 301 * zombie. This is necessary to handle the case where the target 302 * process, e.g. a child, dies before the kevent is negistered. 303 */ 304 if (immediate && filt_proc(kn, NOTE_EXIT)) 305 KNOTE_ACTIVATE(kn); 306 lwkt_reltoken(&p->p_token); 307 PRELE(p); 308 309 return (0); 310 } 311 312 /* 313 * The knote may be attached to a different process, which may exit, 314 * leaving nothing for the knote to be attached to. So when the process 315 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 316 * it will be deleted when read out. However, as part of the knote deletion, 317 * this routine is called, so a check is needed to avoid actually performing 318 * a detach, because the original process does not exist any more. 319 */ 320 static void 321 filt_procdetach(struct knote *kn) 322 { 323 struct proc *p; 324 325 if (kn->kn_status & KN_DETACHED) 326 return; 327 p = kn->kn_ptr.p_proc; 328 knote_remove(&p->p_klist, kn); 329 } 330 331 static int 332 filt_proc(struct knote *kn, long hint) 333 { 334 u_int event; 335 336 /* 337 * mask off extra data 338 */ 339 event = (u_int)hint & NOTE_PCTRLMASK; 340 341 /* 342 * if the user is interested in this event, record it. 343 */ 344 if (kn->kn_sfflags & event) 345 kn->kn_fflags |= event; 346 347 /* 348 * Process is gone, so flag the event as finished. Detach the 349 * knote from the process now because the process will be poof, 350 * gone later on. 351 */ 352 if (event == NOTE_EXIT) { 353 struct proc *p = kn->kn_ptr.p_proc; 354 if ((kn->kn_status & KN_DETACHED) == 0) { 355 PHOLD(p); 356 knote_remove(&p->p_klist, kn); 357 kn->kn_status |= KN_DETACHED; 358 kn->kn_data = p->p_xstat; 359 kn->kn_ptr.p_proc = NULL; 360 PRELE(p); 361 } 362 kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT); 363 return (1); 364 } 365 366 /* 367 * process forked, and user wants to track the new process, 368 * so attach a new knote to it, and immediately report an 369 * event with the parent's pid. 370 */ 371 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) { 372 struct kevent kev; 373 int error; 374 375 /* 376 * register knote with new process. 377 */ 378 kev.ident = hint & NOTE_PDATAMASK; /* pid */ 379 kev.filter = kn->kn_filter; 380 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 381 kev.fflags = kn->kn_sfflags; 382 kev.data = kn->kn_id; /* parent */ 383 kev.udata = kn->kn_kevent.udata; /* preserve udata */ 384 error = kqueue_register(kn->kn_kq, &kev); 385 if (error) 386 kn->kn_fflags |= NOTE_TRACKERR; 387 } 388 389 return (kn->kn_fflags != 0); 390 } 391 392 static void 393 filt_timerreset(struct knote *kn) 394 { 395 struct callout *calloutp; 396 struct timeval tv; 397 int tticks; 398 399 tv.tv_sec = kn->kn_sdata / 1000; 400 tv.tv_usec = (kn->kn_sdata % 1000) * 1000; 401 tticks = tvtohz_high(&tv); 402 calloutp = (struct callout *)kn->kn_hook; 403 callout_reset(calloutp, tticks, filt_timerexpire, kn); 404 } 405 406 /* 407 * The callout interlocks with callout_terminate() but can still 408 * race a deletion so if KN_DELETING is set we just don't touch 409 * the knote. 410 */ 411 static void 412 filt_timerexpire(void *knx) 413 { 414 struct knote *kn = knx; 415 struct kqueue *kq = kn->kn_kq; 416 417 lwkt_getpooltoken(kq); 418 419 /* 420 * Open knote_acquire(), since we can't sleep in callout, 421 * however, we do need to record this expiration. 422 */ 423 kn->kn_data++; 424 if (kn->kn_status & KN_PROCESSING) { 425 kn->kn_status |= KN_REPROCESS; 426 if ((kn->kn_status & KN_DELETING) == 0 && 427 (kn->kn_flags & EV_ONESHOT) == 0) 428 filt_timerreset(kn); 429 lwkt_relpooltoken(kq); 430 return; 431 } 432 KASSERT((kn->kn_status & KN_DELETING) == 0, 433 ("acquire a deleting knote %#x", kn->kn_status)); 434 kn->kn_status |= KN_PROCESSING; 435 436 KNOTE_ACTIVATE(kn); 437 if ((kn->kn_flags & EV_ONESHOT) == 0) 438 filt_timerreset(kn); 439 440 knote_release(kn); 441 442 lwkt_relpooltoken(kq); 443 } 444 445 /* 446 * data contains amount of time to sleep, in milliseconds 447 */ 448 static int 449 filt_timerattach(struct knote *kn) 450 { 451 struct callout *calloutp; 452 int prev_ncallouts; 453 454 prev_ncallouts = atomic_fetchadd_int(&kq_ncallouts, 1); 455 if (prev_ncallouts >= kq_calloutmax) { 456 atomic_subtract_int(&kq_ncallouts, 1); 457 kn->kn_hook = NULL; 458 return (ENOMEM); 459 } 460 461 kn->kn_flags |= EV_CLEAR; /* automatically set */ 462 calloutp = kmalloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 463 callout_init_mp(calloutp); 464 kn->kn_hook = (caddr_t)calloutp; 465 466 filt_timerreset(kn); 467 return (0); 468 } 469 470 /* 471 * This function is called with the knote flagged locked but it is 472 * still possible to race a callout event due to the callback blocking. 473 * We must call callout_terminate() instead of callout_stop() to deal 474 * with the race. 475 */ 476 static void 477 filt_timerdetach(struct knote *kn) 478 { 479 struct callout *calloutp; 480 481 calloutp = (struct callout *)kn->kn_hook; 482 callout_terminate(calloutp); 483 kfree(calloutp, M_KQUEUE); 484 atomic_subtract_int(&kq_ncallouts, 1); 485 } 486 487 static int 488 filt_timer(struct knote *kn, long hint) 489 { 490 491 return (kn->kn_data != 0); 492 } 493 494 /* 495 * EVFILT_USER 496 */ 497 static int 498 filt_userattach(struct knote *kn) 499 { 500 kn->kn_hook = NULL; 501 if (kn->kn_fflags & NOTE_TRIGGER) 502 kn->kn_ptr.hookid = 1; 503 else 504 kn->kn_ptr.hookid = 0; 505 return 0; 506 } 507 508 static void 509 filt_userdetach(struct knote *kn) 510 { 511 /* nothing to do */ 512 } 513 514 static int 515 filt_user(struct knote *kn, long hint) 516 { 517 return (kn->kn_ptr.hookid); 518 } 519 520 static void 521 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 522 { 523 u_int ffctrl; 524 525 switch (type) { 526 case EVENT_REGISTER: 527 if (kev->fflags & NOTE_TRIGGER) 528 kn->kn_ptr.hookid = 1; 529 530 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 531 kev->fflags &= NOTE_FFLAGSMASK; 532 switch (ffctrl) { 533 case NOTE_FFNOP: 534 break; 535 536 case NOTE_FFAND: 537 kn->kn_sfflags &= kev->fflags; 538 break; 539 540 case NOTE_FFOR: 541 kn->kn_sfflags |= kev->fflags; 542 break; 543 544 case NOTE_FFCOPY: 545 kn->kn_sfflags = kev->fflags; 546 break; 547 548 default: 549 /* XXX Return error? */ 550 break; 551 } 552 kn->kn_sdata = kev->data; 553 554 /* 555 * This is not the correct use of EV_CLEAR in an event 556 * modification, it should have been passed as a NOTE instead. 557 * But we need to maintain compatibility with Apple & FreeBSD. 558 * 559 * Note however that EV_CLEAR can still be used when doing 560 * the initial registration of the event and works as expected 561 * (clears the event on reception). 562 */ 563 if (kev->flags & EV_CLEAR) { 564 kn->kn_ptr.hookid = 0; 565 kn->kn_data = 0; 566 kn->kn_fflags = 0; 567 } 568 break; 569 570 case EVENT_PROCESS: 571 *kev = kn->kn_kevent; 572 kev->fflags = kn->kn_sfflags; 573 kev->data = kn->kn_sdata; 574 if (kn->kn_flags & EV_CLEAR) { 575 kn->kn_ptr.hookid = 0; 576 /* kn_data, kn_fflags handled by parent */ 577 } 578 break; 579 580 default: 581 panic("filt_usertouch() - invalid type (%ld)", type); 582 break; 583 } 584 } 585 586 /* 587 * Initialize a kqueue. 588 * 589 * NOTE: The lwp/proc code initializes a kqueue for select/poll ops. 590 * 591 * MPSAFE 592 */ 593 void 594 kqueue_init(struct kqueue *kq, struct filedesc *fdp) 595 { 596 TAILQ_INIT(&kq->kq_knpend); 597 TAILQ_INIT(&kq->kq_knlist); 598 kq->kq_count = 0; 599 kq->kq_fdp = fdp; 600 SLIST_INIT(&kq->kq_kqinfo.ki_note); 601 } 602 603 /* 604 * Terminate a kqueue. Freeing the actual kq itself is left up to the 605 * caller (it might be embedded in a lwp so we don't do it here). 606 * 607 * The kq's knlist must be completely eradicated so block on any 608 * processing races. 609 */ 610 void 611 kqueue_terminate(struct kqueue *kq) 612 { 613 struct lwkt_token *tok; 614 struct knote *kn; 615 616 tok = lwkt_token_pool_lookup(kq); 617 lwkt_gettoken(tok); 618 while ((kn = TAILQ_FIRST(&kq->kq_knlist)) != NULL) { 619 if (knote_acquire(kn)) 620 knote_detach_and_drop(kn); 621 } 622 lwkt_reltoken(tok); 623 624 if (kq->kq_knhash) { 625 hashdestroy(kq->kq_knhash, M_KQUEUE, kq->kq_knhashmask); 626 kq->kq_knhash = NULL; 627 kq->kq_knhashmask = 0; 628 } 629 } 630 631 /* 632 * MPSAFE 633 */ 634 int 635 sys_kqueue(struct kqueue_args *uap) 636 { 637 struct thread *td = curthread; 638 struct kqueue *kq; 639 struct file *fp; 640 int fd, error; 641 642 error = falloc(td->td_lwp, &fp, &fd); 643 if (error) 644 return (error); 645 fp->f_flag = FREAD | FWRITE; 646 fp->f_type = DTYPE_KQUEUE; 647 fp->f_ops = &kqueueops; 648 649 kq = kmalloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO); 650 kqueue_init(kq, td->td_proc->p_fd); 651 fp->f_data = kq; 652 653 fsetfd(kq->kq_fdp, fp, fd); 654 uap->sysmsg_result = fd; 655 fdrop(fp); 656 return (error); 657 } 658 659 /* 660 * Copy 'count' items into the destination list pointed to by uap->eventlist. 661 */ 662 static int 663 kevent_copyout(void *arg, struct kevent *kevp, int count, int *res) 664 { 665 struct kevent_copyin_args *kap; 666 int error; 667 668 kap = (struct kevent_copyin_args *)arg; 669 670 error = copyout(kevp, kap->ka->eventlist, count * sizeof(*kevp)); 671 if (error == 0) { 672 kap->ka->eventlist += count; 673 *res += count; 674 } else { 675 *res = -1; 676 } 677 678 return (error); 679 } 680 681 /* 682 * Copy at most 'max' items from the list pointed to by kap->changelist, 683 * return number of items in 'events'. 684 */ 685 static int 686 kevent_copyin(void *arg, struct kevent *kevp, int max, int *events) 687 { 688 struct kevent_copyin_args *kap; 689 int error, count; 690 691 kap = (struct kevent_copyin_args *)arg; 692 693 count = min(kap->ka->nchanges - kap->pchanges, max); 694 error = copyin(kap->ka->changelist, kevp, count * sizeof *kevp); 695 if (error == 0) { 696 kap->ka->changelist += count; 697 kap->pchanges += count; 698 *events = count; 699 } 700 701 return (error); 702 } 703 704 /* 705 * MPSAFE 706 */ 707 int 708 kern_kevent(struct kqueue *kq, int nevents, int *res, void *uap, 709 k_copyin_fn kevent_copyinfn, k_copyout_fn kevent_copyoutfn, 710 struct timespec *tsp_in) 711 { 712 struct kevent *kevp; 713 struct timespec *tsp, ats; 714 int i, n, total, error, nerrors = 0; 715 int lres; 716 int limit = kq_checkloop; 717 struct kevent kev[KQ_NEVENTS]; 718 struct knote marker; 719 struct lwkt_token *tok; 720 721 if (tsp_in == NULL || tsp_in->tv_sec || tsp_in->tv_nsec) 722 atomic_set_int(&curthread->td_mpflags, TDF_MP_BATCH_DEMARC); 723 724 tsp = tsp_in; 725 *res = 0; 726 727 for (;;) { 728 n = 0; 729 error = kevent_copyinfn(uap, kev, KQ_NEVENTS, &n); 730 if (error) 731 return error; 732 if (n == 0) 733 break; 734 for (i = 0; i < n; i++) { 735 kevp = &kev[i]; 736 kevp->flags &= ~EV_SYSFLAGS; 737 error = kqueue_register(kq, kevp); 738 739 /* 740 * If a registration returns an error we 741 * immediately post the error. The kevent() 742 * call itself will fail with the error if 743 * no space is available for posting. 744 * 745 * Such errors normally bypass the timeout/blocking 746 * code. However, if the copyoutfn function refuses 747 * to post the error (see sys_poll()), then we 748 * ignore it too. 749 */ 750 if (error || (kevp->flags & EV_RECEIPT)) { 751 kevp->flags = EV_ERROR; 752 kevp->data = error; 753 lres = *res; 754 kevent_copyoutfn(uap, kevp, 1, res); 755 if (*res < 0) { 756 return error; 757 } else if (lres != *res) { 758 nevents--; 759 nerrors++; 760 } 761 } 762 } 763 } 764 if (nerrors) 765 return 0; 766 767 /* 768 * Acquire/wait for events - setup timeout 769 */ 770 if (tsp != NULL) { 771 if (tsp->tv_sec || tsp->tv_nsec) { 772 getnanouptime(&ats); 773 timespecadd(tsp, &ats); /* tsp = target time */ 774 } 775 } 776 777 /* 778 * Loop as required. 779 * 780 * Collect as many events as we can. Sleeping on successive 781 * loops is disabled if copyoutfn has incremented (*res). 782 * 783 * The loop stops if an error occurs, all events have been 784 * scanned (the marker has been reached), or fewer than the 785 * maximum number of events is found. 786 * 787 * The copyoutfn function does not have to increment (*res) in 788 * order for the loop to continue. 789 * 790 * NOTE: doselect() usually passes 0x7FFFFFFF for nevents. 791 */ 792 total = 0; 793 error = 0; 794 marker.kn_filter = EVFILT_MARKER; 795 marker.kn_status = KN_PROCESSING; 796 tok = lwkt_token_pool_lookup(kq); 797 lwkt_gettoken(tok); 798 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); 799 lwkt_reltoken(tok); 800 while ((n = nevents - total) > 0) { 801 if (n > KQ_NEVENTS) 802 n = KQ_NEVENTS; 803 804 /* 805 * If no events are pending sleep until timeout (if any) 806 * or an event occurs. 807 * 808 * After the sleep completes the marker is moved to the 809 * end of the list, making any received events available 810 * to our scan. 811 */ 812 if (kq->kq_count == 0 && *res == 0) { 813 int timeout; 814 815 if (tsp == NULL) { 816 timeout = 0; 817 } else if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) { 818 error = EWOULDBLOCK; 819 break; 820 } else { 821 struct timespec atx = *tsp; 822 823 getnanouptime(&ats); 824 timespecsub(&atx, &ats); 825 if (atx.tv_sec < 0) { 826 error = EWOULDBLOCK; 827 break; 828 } else { 829 timeout = atx.tv_sec > 24 * 60 * 60 ? 830 24 * 60 * 60 * hz : 831 tstohz_high(&atx); 832 } 833 } 834 835 lwkt_gettoken(tok); 836 if (kq->kq_count == 0) { 837 kq->kq_state |= KQ_SLEEP; 838 error = tsleep(kq, PCATCH, "kqread", timeout); 839 840 /* don't restart after signals... */ 841 if (error == ERESTART) 842 error = EINTR; 843 if (error) { 844 lwkt_reltoken(tok); 845 break; 846 } 847 848 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); 849 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, 850 kn_tqe); 851 } 852 lwkt_reltoken(tok); 853 } 854 855 /* 856 * Process all received events 857 * Account for all non-spurious events in our total 858 */ 859 i = kqueue_scan(kq, kev, n, &marker); 860 if (i) { 861 lres = *res; 862 error = kevent_copyoutfn(uap, kev, i, res); 863 total += *res - lres; 864 if (error) 865 break; 866 } 867 if (limit && --limit == 0) 868 panic("kqueue: checkloop failed i=%d", i); 869 870 /* 871 * Normally when fewer events are returned than requested 872 * we can stop. However, if only spurious events were 873 * collected the copyout will not bump (*res) and we have 874 * to continue. 875 */ 876 if (i < n && *res) 877 break; 878 879 /* 880 * Deal with an edge case where spurious events can cause 881 * a loop to occur without moving the marker. This can 882 * prevent kqueue_scan() from picking up new events which 883 * race us. We must be sure to move the marker for this 884 * case. 885 * 886 * NOTE: We do not want to move the marker if events 887 * were scanned because normal kqueue operations 888 * may reactivate events. Moving the marker in 889 * that case could result in duplicates for the 890 * same event. 891 */ 892 if (i == 0) { 893 lwkt_gettoken(tok); 894 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); 895 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); 896 lwkt_reltoken(tok); 897 } 898 } 899 lwkt_gettoken(tok); 900 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); 901 lwkt_reltoken(tok); 902 903 /* Timeouts do not return EWOULDBLOCK. */ 904 if (error == EWOULDBLOCK) 905 error = 0; 906 return error; 907 } 908 909 /* 910 * MPALMOSTSAFE 911 */ 912 int 913 sys_kevent(struct kevent_args *uap) 914 { 915 struct thread *td = curthread; 916 struct proc *p = td->td_proc; 917 struct timespec ts, *tsp; 918 struct kqueue *kq; 919 struct file *fp = NULL; 920 struct kevent_copyin_args *kap, ka; 921 int error; 922 923 if (uap->timeout) { 924 error = copyin(uap->timeout, &ts, sizeof(ts)); 925 if (error) 926 return (error); 927 tsp = &ts; 928 } else { 929 tsp = NULL; 930 } 931 fp = holdfp(p->p_fd, uap->fd, -1); 932 if (fp == NULL) 933 return (EBADF); 934 if (fp->f_type != DTYPE_KQUEUE) { 935 fdrop(fp); 936 return (EBADF); 937 } 938 939 kq = (struct kqueue *)fp->f_data; 940 941 kap = &ka; 942 kap->ka = uap; 943 kap->pchanges = 0; 944 945 error = kern_kevent(kq, uap->nevents, &uap->sysmsg_result, kap, 946 kevent_copyin, kevent_copyout, tsp); 947 948 fdrop(fp); 949 950 return (error); 951 } 952 953 int 954 kqueue_register(struct kqueue *kq, struct kevent *kev) 955 { 956 struct lwkt_token *tok; 957 struct filedesc *fdp = kq->kq_fdp; 958 struct filterops *fops; 959 struct file *fp = NULL; 960 struct knote *kn = NULL; 961 int error = 0; 962 963 if (kev->filter < 0) { 964 if (kev->filter + EVFILT_SYSCOUNT < 0) 965 return (EINVAL); 966 fops = sysfilt_ops[~kev->filter]; /* to 0-base index */ 967 } else { 968 /* 969 * XXX 970 * filter attach routine is responsible for insuring that 971 * the identifier can be attached to it. 972 */ 973 return (EINVAL); 974 } 975 976 tok = lwkt_token_pool_lookup(kq); 977 lwkt_gettoken(tok); 978 if (fops->f_flags & FILTEROP_ISFD) { 979 /* validate descriptor */ 980 fp = holdfp(fdp, kev->ident, -1); 981 if (fp == NULL) { 982 lwkt_reltoken(tok); 983 return (EBADF); 984 } 985 lwkt_getpooltoken(&fp->f_klist); 986 again1: 987 SLIST_FOREACH(kn, &fp->f_klist, kn_link) { 988 if (kn->kn_kq == kq && 989 kn->kn_filter == kev->filter && 990 kn->kn_id == kev->ident) { 991 if (knote_acquire(kn) == 0) 992 goto again1; 993 break; 994 } 995 } 996 lwkt_relpooltoken(&fp->f_klist); 997 } else { 998 if (kq->kq_knhashmask) { 999 struct klist *list; 1000 1001 list = &kq->kq_knhash[ 1002 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1003 lwkt_getpooltoken(list); 1004 again2: 1005 SLIST_FOREACH(kn, list, kn_link) { 1006 if (kn->kn_id == kev->ident && 1007 kn->kn_filter == kev->filter) { 1008 if (knote_acquire(kn) == 0) 1009 goto again2; 1010 break; 1011 } 1012 } 1013 lwkt_relpooltoken(list); 1014 } 1015 } 1016 1017 /* 1018 * NOTE: At this point if kn is non-NULL we will have acquired 1019 * it and set KN_PROCESSING. 1020 */ 1021 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) { 1022 error = ENOENT; 1023 goto done; 1024 } 1025 1026 /* 1027 * kn now contains the matching knote, or NULL if no match 1028 */ 1029 if (kev->flags & EV_ADD) { 1030 if (kn == NULL) { 1031 kn = knote_alloc(); 1032 kn->kn_fp = fp; 1033 kn->kn_kq = kq; 1034 kn->kn_fop = fops; 1035 1036 /* 1037 * apply reference count to knote structure, and 1038 * do not release it at the end of this routine. 1039 */ 1040 fp = NULL; 1041 1042 kn->kn_sfflags = kev->fflags; 1043 kn->kn_sdata = kev->data; 1044 kev->fflags = 0; 1045 kev->data = 0; 1046 kn->kn_kevent = *kev; 1047 1048 /* 1049 * KN_PROCESSING prevents the knote from getting 1050 * ripped out from under us while we are trying 1051 * to attach it, in case the attach blocks. 1052 */ 1053 kn->kn_status = KN_PROCESSING; 1054 knote_attach(kn); 1055 if ((error = filter_attach(kn)) != 0) { 1056 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1057 knote_drop(kn); 1058 goto done; 1059 } 1060 1061 /* 1062 * Interlock against close races which either tried 1063 * to remove our knote while we were blocked or missed 1064 * it entirely prior to our attachment. We do not 1065 * want to end up with a knote on a closed descriptor. 1066 */ 1067 if ((fops->f_flags & FILTEROP_ISFD) && 1068 checkfdclosed(fdp, kev->ident, kn->kn_fp)) { 1069 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1070 } 1071 } else { 1072 /* 1073 * The user may change some filter values after the 1074 * initial EV_ADD, but doing so will not reset any 1075 * filter which have already been triggered. 1076 */ 1077 KKASSERT(kn->kn_status & KN_PROCESSING); 1078 if (fops == &user_filtops) { 1079 filt_usertouch(kn, kev, EVENT_REGISTER); 1080 } else { 1081 kn->kn_sfflags = kev->fflags; 1082 kn->kn_sdata = kev->data; 1083 kn->kn_kevent.udata = kev->udata; 1084 } 1085 } 1086 1087 /* 1088 * Execute the filter event to immediately activate the 1089 * knote if necessary. If reprocessing events are pending 1090 * due to blocking above we do not run the filter here 1091 * but instead let knote_release() do it. Otherwise we 1092 * might run the filter on a deleted event. 1093 */ 1094 if ((kn->kn_status & KN_REPROCESS) == 0) { 1095 if (filter_event(kn, 0)) 1096 KNOTE_ACTIVATE(kn); 1097 } 1098 } else if (kev->flags & EV_DELETE) { 1099 /* 1100 * Delete the existing knote 1101 */ 1102 knote_detach_and_drop(kn); 1103 goto done; 1104 } else { 1105 /* 1106 * Modify an existing event. 1107 * 1108 * The user may change some filter values after the 1109 * initial EV_ADD, but doing so will not reset any 1110 * filter which have already been triggered. 1111 */ 1112 KKASSERT(kn->kn_status & KN_PROCESSING); 1113 if (fops == &user_filtops) { 1114 filt_usertouch(kn, kev, EVENT_REGISTER); 1115 } else { 1116 kn->kn_sfflags = kev->fflags; 1117 kn->kn_sdata = kev->data; 1118 kn->kn_kevent.udata = kev->udata; 1119 } 1120 1121 /* 1122 * Execute the filter event to immediately activate the 1123 * knote if necessary. If reprocessing events are pending 1124 * due to blocking above we do not run the filter here 1125 * but instead let knote_release() do it. Otherwise we 1126 * might run the filter on a deleted event. 1127 */ 1128 if ((kn->kn_status & KN_REPROCESS) == 0) { 1129 if (filter_event(kn, 0)) 1130 KNOTE_ACTIVATE(kn); 1131 } 1132 } 1133 1134 /* 1135 * Disablement does not deactivate a knote here. 1136 */ 1137 if ((kev->flags & EV_DISABLE) && 1138 ((kn->kn_status & KN_DISABLED) == 0)) { 1139 kn->kn_status |= KN_DISABLED; 1140 } 1141 1142 /* 1143 * Re-enablement may have to immediately enqueue an active knote. 1144 */ 1145 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1146 kn->kn_status &= ~KN_DISABLED; 1147 if ((kn->kn_status & KN_ACTIVE) && 1148 ((kn->kn_status & KN_QUEUED) == 0)) { 1149 knote_enqueue(kn); 1150 } 1151 } 1152 1153 /* 1154 * Handle any required reprocessing 1155 */ 1156 knote_release(kn); 1157 /* kn may be invalid now */ 1158 1159 done: 1160 lwkt_reltoken(tok); 1161 if (fp != NULL) 1162 fdrop(fp); 1163 return (error); 1164 } 1165 1166 /* 1167 * Scan the kqueue, return the number of active events placed in kevp up 1168 * to count. 1169 * 1170 * Continuous mode events may get recycled, do not continue scanning past 1171 * marker unless no events have been collected. 1172 */ 1173 static int 1174 kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, 1175 struct knote *marker) 1176 { 1177 struct knote *kn, local_marker; 1178 int total; 1179 1180 total = 0; 1181 local_marker.kn_filter = EVFILT_MARKER; 1182 local_marker.kn_status = KN_PROCESSING; 1183 1184 lwkt_getpooltoken(kq); 1185 1186 /* 1187 * Collect events. 1188 */ 1189 TAILQ_INSERT_HEAD(&kq->kq_knpend, &local_marker, kn_tqe); 1190 while (count) { 1191 kn = TAILQ_NEXT(&local_marker, kn_tqe); 1192 if (kn->kn_filter == EVFILT_MARKER) { 1193 /* Marker reached, we are done */ 1194 if (kn == marker) 1195 break; 1196 1197 /* Move local marker past some other threads marker */ 1198 kn = TAILQ_NEXT(kn, kn_tqe); 1199 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); 1200 TAILQ_INSERT_BEFORE(kn, &local_marker, kn_tqe); 1201 continue; 1202 } 1203 1204 /* 1205 * We can't skip a knote undergoing processing, otherwise 1206 * we risk not returning it when the user process expects 1207 * it should be returned. Sleep and retry. 1208 */ 1209 if (knote_acquire(kn) == 0) 1210 continue; 1211 1212 /* 1213 * Remove the event for processing. 1214 * 1215 * WARNING! We must leave KN_QUEUED set to prevent the 1216 * event from being KNOTE_ACTIVATE()d while 1217 * the queue state is in limbo, in case we 1218 * block. 1219 */ 1220 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); 1221 kq->kq_count--; 1222 1223 /* 1224 * We have to deal with an extremely important race against 1225 * file descriptor close()s here. The file descriptor can 1226 * disappear MPSAFE, and there is a small window of 1227 * opportunity between that and the call to knote_fdclose(). 1228 * 1229 * If we hit that window here while doselect or dopoll is 1230 * trying to delete a spurious event they will not be able 1231 * to match up the event against a knote and will go haywire. 1232 */ 1233 if ((kn->kn_fop->f_flags & FILTEROP_ISFD) && 1234 checkfdclosed(kq->kq_fdp, kn->kn_kevent.ident, kn->kn_fp)) { 1235 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1236 } 1237 1238 if (kn->kn_status & KN_DISABLED) { 1239 /* 1240 * If disabled we ensure the event is not queued 1241 * but leave its active bit set. On re-enablement 1242 * the event may be immediately triggered. 1243 */ 1244 kn->kn_status &= ~KN_QUEUED; 1245 } else if ((kn->kn_flags & EV_ONESHOT) == 0 && 1246 (kn->kn_status & KN_DELETING) == 0 && 1247 filter_event(kn, 0) == 0) { 1248 /* 1249 * If not running in one-shot mode and the event 1250 * is no longer present we ensure it is removed 1251 * from the queue and ignore it. 1252 */ 1253 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1254 } else { 1255 /* 1256 * Post the event 1257 */ 1258 if (kn->kn_fop == &user_filtops) 1259 filt_usertouch(kn, kevp, EVENT_PROCESS); 1260 else 1261 *kevp = kn->kn_kevent; 1262 ++kevp; 1263 ++total; 1264 --count; 1265 1266 if (kn->kn_flags & EV_ONESHOT) { 1267 kn->kn_status &= ~KN_QUEUED; 1268 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1269 } else { 1270 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1271 if (kn->kn_flags & EV_CLEAR) { 1272 kn->kn_data = 0; 1273 kn->kn_fflags = 0; 1274 } 1275 if (kn->kn_flags & EV_DISPATCH) { 1276 kn->kn_status |= KN_DISABLED; 1277 } 1278 kn->kn_status &= ~(KN_QUEUED | 1279 KN_ACTIVE); 1280 } else { 1281 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); 1282 kq->kq_count++; 1283 } 1284 } 1285 } 1286 1287 /* 1288 * Handle any post-processing states 1289 */ 1290 knote_release(kn); 1291 } 1292 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); 1293 1294 lwkt_relpooltoken(kq); 1295 return (total); 1296 } 1297 1298 /* 1299 * XXX 1300 * This could be expanded to call kqueue_scan, if desired. 1301 * 1302 * MPSAFE 1303 */ 1304 static int 1305 kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags) 1306 { 1307 return (ENXIO); 1308 } 1309 1310 /* 1311 * MPSAFE 1312 */ 1313 static int 1314 kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags) 1315 { 1316 return (ENXIO); 1317 } 1318 1319 /* 1320 * MPALMOSTSAFE 1321 */ 1322 static int 1323 kqueue_ioctl(struct file *fp, u_long com, caddr_t data, 1324 struct ucred *cred, struct sysmsg *msg) 1325 { 1326 struct lwkt_token *tok; 1327 struct kqueue *kq; 1328 int error; 1329 1330 kq = (struct kqueue *)fp->f_data; 1331 tok = lwkt_token_pool_lookup(kq); 1332 lwkt_gettoken(tok); 1333 1334 switch(com) { 1335 case FIOASYNC: 1336 if (*(int *)data) 1337 kq->kq_state |= KQ_ASYNC; 1338 else 1339 kq->kq_state &= ~KQ_ASYNC; 1340 error = 0; 1341 break; 1342 case FIOSETOWN: 1343 error = fsetown(*(int *)data, &kq->kq_sigio); 1344 break; 1345 default: 1346 error = ENOTTY; 1347 break; 1348 } 1349 lwkt_reltoken(tok); 1350 return (error); 1351 } 1352 1353 /* 1354 * MPSAFE 1355 */ 1356 static int 1357 kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred) 1358 { 1359 struct kqueue *kq = (struct kqueue *)fp->f_data; 1360 1361 bzero((void *)st, sizeof(*st)); 1362 st->st_size = kq->kq_count; 1363 st->st_blksize = sizeof(struct kevent); 1364 st->st_mode = S_IFIFO; 1365 return (0); 1366 } 1367 1368 /* 1369 * MPSAFE 1370 */ 1371 static int 1372 kqueue_close(struct file *fp) 1373 { 1374 struct kqueue *kq = (struct kqueue *)fp->f_data; 1375 1376 kqueue_terminate(kq); 1377 1378 fp->f_data = NULL; 1379 funsetown(&kq->kq_sigio); 1380 1381 kfree(kq, M_KQUEUE); 1382 return (0); 1383 } 1384 1385 static void 1386 kqueue_wakeup(struct kqueue *kq) 1387 { 1388 if (kq->kq_state & KQ_SLEEP) { 1389 kq->kq_state &= ~KQ_SLEEP; 1390 if (kq_wakeup_one) 1391 wakeup_one(kq); 1392 else 1393 wakeup(kq); 1394 } 1395 KNOTE(&kq->kq_kqinfo.ki_note, 0); 1396 } 1397 1398 /* 1399 * Calls filterops f_attach function, acquiring mplock if filter is not 1400 * marked as FILTEROP_MPSAFE. 1401 * 1402 * Caller must be holding the related kq token 1403 */ 1404 static int 1405 filter_attach(struct knote *kn) 1406 { 1407 int ret; 1408 1409 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { 1410 ret = kn->kn_fop->f_attach(kn); 1411 } else { 1412 get_mplock(); 1413 ret = kn->kn_fop->f_attach(kn); 1414 rel_mplock(); 1415 } 1416 return (ret); 1417 } 1418 1419 /* 1420 * Detach the knote and drop it, destroying the knote. 1421 * 1422 * Calls filterops f_detach function, acquiring mplock if filter is not 1423 * marked as FILTEROP_MPSAFE. 1424 * 1425 * Caller must be holding the related kq token 1426 */ 1427 static void 1428 knote_detach_and_drop(struct knote *kn) 1429 { 1430 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1431 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { 1432 kn->kn_fop->f_detach(kn); 1433 } else { 1434 get_mplock(); 1435 kn->kn_fop->f_detach(kn); 1436 rel_mplock(); 1437 } 1438 knote_drop(kn); 1439 } 1440 1441 /* 1442 * Calls filterops f_event function, acquiring mplock if filter is not 1443 * marked as FILTEROP_MPSAFE. 1444 * 1445 * If the knote is in the middle of being created or deleted we cannot 1446 * safely call the filter op. 1447 * 1448 * Caller must be holding the related kq token 1449 */ 1450 static int 1451 filter_event(struct knote *kn, long hint) 1452 { 1453 int ret; 1454 1455 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { 1456 ret = kn->kn_fop->f_event(kn, hint); 1457 } else { 1458 get_mplock(); 1459 ret = kn->kn_fop->f_event(kn, hint); 1460 rel_mplock(); 1461 } 1462 return (ret); 1463 } 1464 1465 /* 1466 * Walk down a list of knotes, activating them if their event has triggered. 1467 * 1468 * If we encounter any knotes which are undergoing processing we just mark 1469 * them for reprocessing and do not try to [re]activate the knote. However, 1470 * if a hint is being passed we have to wait and that makes things a bit 1471 * sticky. 1472 */ 1473 void 1474 knote(struct klist *list, long hint) 1475 { 1476 struct kqueue *kq; 1477 struct knote *kn; 1478 struct knote *kntmp; 1479 1480 lwkt_getpooltoken(list); 1481 restart: 1482 SLIST_FOREACH(kn, list, kn_next) { 1483 kq = kn->kn_kq; 1484 lwkt_getpooltoken(kq); 1485 1486 /* temporary verification hack */ 1487 SLIST_FOREACH(kntmp, list, kn_next) { 1488 if (kn == kntmp) 1489 break; 1490 } 1491 if (kn != kntmp || kn->kn_kq != kq) { 1492 lwkt_relpooltoken(kq); 1493 goto restart; 1494 } 1495 1496 if (kn->kn_status & KN_PROCESSING) { 1497 /* 1498 * Someone else is processing the knote, ask the 1499 * other thread to reprocess it and don't mess 1500 * with it otherwise. 1501 */ 1502 if (hint == 0) { 1503 kn->kn_status |= KN_REPROCESS; 1504 lwkt_relpooltoken(kq); 1505 continue; 1506 } 1507 1508 /* 1509 * If the hint is non-zero we have to wait or risk 1510 * losing the state the caller is trying to update. 1511 * 1512 * XXX This is a real problem, certain process 1513 * and signal filters will bump kn_data for 1514 * already-processed notes more than once if 1515 * we restart the list scan. FIXME. 1516 */ 1517 kn->kn_status |= KN_WAITING | KN_REPROCESS; 1518 tsleep(kn, 0, "knotec", hz); 1519 lwkt_relpooltoken(kq); 1520 goto restart; 1521 } 1522 1523 /* 1524 * Become the reprocessing master ourselves. 1525 * 1526 * If hint is non-zero running the event is mandatory 1527 * when not deleting so do it whether reprocessing is 1528 * set or not. 1529 */ 1530 kn->kn_status |= KN_PROCESSING; 1531 if ((kn->kn_status & KN_DELETING) == 0) { 1532 if (filter_event(kn, hint)) 1533 KNOTE_ACTIVATE(kn); 1534 } 1535 if (knote_release(kn)) { 1536 lwkt_relpooltoken(kq); 1537 goto restart; 1538 } 1539 lwkt_relpooltoken(kq); 1540 } 1541 lwkt_relpooltoken(list); 1542 } 1543 1544 /* 1545 * Insert knote at head of klist. 1546 * 1547 * This function may only be called via a filter function and thus 1548 * kq_token should already be held and marked for processing. 1549 */ 1550 void 1551 knote_insert(struct klist *klist, struct knote *kn) 1552 { 1553 lwkt_getpooltoken(klist); 1554 KKASSERT(kn->kn_status & KN_PROCESSING); 1555 SLIST_INSERT_HEAD(klist, kn, kn_next); 1556 lwkt_relpooltoken(klist); 1557 } 1558 1559 /* 1560 * Remove knote from a klist 1561 * 1562 * This function may only be called via a filter function and thus 1563 * kq_token should already be held and marked for processing. 1564 */ 1565 void 1566 knote_remove(struct klist *klist, struct knote *kn) 1567 { 1568 lwkt_getpooltoken(klist); 1569 KKASSERT(kn->kn_status & KN_PROCESSING); 1570 SLIST_REMOVE(klist, kn, knote, kn_next); 1571 lwkt_relpooltoken(klist); 1572 } 1573 1574 #if 0 1575 /* 1576 * Remove all knotes from a specified klist 1577 * 1578 * Only called from aio. 1579 */ 1580 void 1581 knote_empty(struct klist *list) 1582 { 1583 struct knote *kn; 1584 1585 lwkt_gettoken(&kq_token); 1586 while ((kn = SLIST_FIRST(list)) != NULL) { 1587 if (knote_acquire(kn)) 1588 knote_detach_and_drop(kn); 1589 } 1590 lwkt_reltoken(&kq_token); 1591 } 1592 #endif 1593 1594 void 1595 knote_assume_knotes(struct kqinfo *src, struct kqinfo *dst, 1596 struct filterops *ops, void *hook) 1597 { 1598 struct kqueue *kq; 1599 struct knote *kn; 1600 1601 lwkt_getpooltoken(&src->ki_note); 1602 lwkt_getpooltoken(&dst->ki_note); 1603 while ((kn = SLIST_FIRST(&src->ki_note)) != NULL) { 1604 kq = kn->kn_kq; 1605 lwkt_getpooltoken(kq); 1606 if (SLIST_FIRST(&src->ki_note) != kn || kn->kn_kq != kq) { 1607 lwkt_relpooltoken(kq); 1608 continue; 1609 } 1610 if (knote_acquire(kn)) { 1611 knote_remove(&src->ki_note, kn); 1612 kn->kn_fop = ops; 1613 kn->kn_hook = hook; 1614 knote_insert(&dst->ki_note, kn); 1615 knote_release(kn); 1616 /* kn may be invalid now */ 1617 } 1618 lwkt_relpooltoken(kq); 1619 } 1620 lwkt_relpooltoken(&dst->ki_note); 1621 lwkt_relpooltoken(&src->ki_note); 1622 } 1623 1624 /* 1625 * Remove all knotes referencing a specified fd 1626 */ 1627 void 1628 knote_fdclose(struct file *fp, struct filedesc *fdp, int fd) 1629 { 1630 struct kqueue *kq; 1631 struct knote *kn; 1632 struct knote *kntmp; 1633 1634 lwkt_getpooltoken(&fp->f_klist); 1635 restart: 1636 SLIST_FOREACH(kn, &fp->f_klist, kn_link) { 1637 if (kn->kn_kq->kq_fdp == fdp && kn->kn_id == fd) { 1638 kq = kn->kn_kq; 1639 lwkt_getpooltoken(kq); 1640 1641 /* temporary verification hack */ 1642 SLIST_FOREACH(kntmp, &fp->f_klist, kn_link) { 1643 if (kn == kntmp) 1644 break; 1645 } 1646 if (kn != kntmp || kn->kn_kq->kq_fdp != fdp || 1647 kn->kn_id != fd || kn->kn_kq != kq) { 1648 lwkt_relpooltoken(kq); 1649 goto restart; 1650 } 1651 if (knote_acquire(kn)) 1652 knote_detach_and_drop(kn); 1653 lwkt_relpooltoken(kq); 1654 goto restart; 1655 } 1656 } 1657 lwkt_relpooltoken(&fp->f_klist); 1658 } 1659 1660 /* 1661 * Low level attach function. 1662 * 1663 * The knote should already be marked for processing. 1664 * Caller must hold the related kq token. 1665 */ 1666 static void 1667 knote_attach(struct knote *kn) 1668 { 1669 struct klist *list; 1670 struct kqueue *kq = kn->kn_kq; 1671 1672 if (kn->kn_fop->f_flags & FILTEROP_ISFD) { 1673 KKASSERT(kn->kn_fp); 1674 list = &kn->kn_fp->f_klist; 1675 } else { 1676 if (kq->kq_knhashmask == 0) 1677 kq->kq_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1678 &kq->kq_knhashmask); 1679 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1680 } 1681 lwkt_getpooltoken(list); 1682 SLIST_INSERT_HEAD(list, kn, kn_link); 1683 lwkt_relpooltoken(list); 1684 TAILQ_INSERT_HEAD(&kq->kq_knlist, kn, kn_kqlink); 1685 } 1686 1687 /* 1688 * Low level drop function. 1689 * 1690 * The knote should already be marked for processing. 1691 * Caller must hold the related kq token. 1692 */ 1693 static void 1694 knote_drop(struct knote *kn) 1695 { 1696 struct kqueue *kq; 1697 struct klist *list; 1698 1699 kq = kn->kn_kq; 1700 1701 if (kn->kn_fop->f_flags & FILTEROP_ISFD) 1702 list = &kn->kn_fp->f_klist; 1703 else 1704 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1705 1706 lwkt_getpooltoken(list); 1707 SLIST_REMOVE(list, kn, knote, kn_link); 1708 lwkt_relpooltoken(list); 1709 TAILQ_REMOVE(&kq->kq_knlist, kn, kn_kqlink); 1710 if (kn->kn_status & KN_QUEUED) 1711 knote_dequeue(kn); 1712 if (kn->kn_fop->f_flags & FILTEROP_ISFD) { 1713 fdrop(kn->kn_fp); 1714 kn->kn_fp = NULL; 1715 } 1716 knote_free(kn); 1717 } 1718 1719 /* 1720 * Low level enqueue function. 1721 * 1722 * The knote should already be marked for processing. 1723 * Caller must be holding the kq token 1724 */ 1725 static void 1726 knote_enqueue(struct knote *kn) 1727 { 1728 struct kqueue *kq = kn->kn_kq; 1729 1730 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 1731 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); 1732 kn->kn_status |= KN_QUEUED; 1733 ++kq->kq_count; 1734 1735 /* 1736 * Send SIGIO on request (typically set up as a mailbox signal) 1737 */ 1738 if (kq->kq_sigio && (kq->kq_state & KQ_ASYNC) && kq->kq_count == 1) 1739 pgsigio(kq->kq_sigio, SIGIO, 0); 1740 1741 kqueue_wakeup(kq); 1742 } 1743 1744 /* 1745 * Low level dequeue function. 1746 * 1747 * The knote should already be marked for processing. 1748 * Caller must be holding the kq token 1749 */ 1750 static void 1751 knote_dequeue(struct knote *kn) 1752 { 1753 struct kqueue *kq = kn->kn_kq; 1754 1755 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 1756 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); 1757 kn->kn_status &= ~KN_QUEUED; 1758 kq->kq_count--; 1759 } 1760 1761 static struct knote * 1762 knote_alloc(void) 1763 { 1764 return kmalloc(sizeof(struct knote), M_KQUEUE, M_WAITOK); 1765 } 1766 1767 static void 1768 knote_free(struct knote *kn) 1769 { 1770 kfree(kn, M_KQUEUE); 1771 } 1772