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 /* 61 * Global token for kqueue subsystem 62 */ 63 #if 0 64 struct lwkt_token kq_token = LWKT_TOKEN_INITIALIZER(kq_token); 65 SYSCTL_LONG(_lwkt, OID_AUTO, kq_collisions, 66 CTLFLAG_RW, &kq_token.t_collisions, 0, 67 "Collision counter of kq_token"); 68 #endif 69 70 MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 71 72 struct kevent_copyin_args { 73 struct kevent_args *ka; 74 int pchanges; 75 }; 76 77 static int kqueue_sleep(struct kqueue *kq, struct timespec *tsp); 78 static int kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, 79 struct knote *marker); 80 static int kqueue_read(struct file *fp, struct uio *uio, 81 struct ucred *cred, int flags); 82 static int kqueue_write(struct file *fp, struct uio *uio, 83 struct ucred *cred, int flags); 84 static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data, 85 struct ucred *cred, struct sysmsg *msg); 86 static int kqueue_kqfilter(struct file *fp, struct knote *kn); 87 static int kqueue_stat(struct file *fp, struct stat *st, 88 struct ucred *cred); 89 static int kqueue_close(struct file *fp); 90 static void kqueue_wakeup(struct kqueue *kq); 91 static int filter_attach(struct knote *kn); 92 static int filter_event(struct knote *kn, long hint); 93 94 /* 95 * MPSAFE 96 */ 97 static struct fileops kqueueops = { 98 .fo_read = kqueue_read, 99 .fo_write = kqueue_write, 100 .fo_ioctl = kqueue_ioctl, 101 .fo_kqfilter = kqueue_kqfilter, 102 .fo_stat = kqueue_stat, 103 .fo_close = kqueue_close, 104 .fo_shutdown = nofo_shutdown 105 }; 106 107 static void knote_attach(struct knote *kn); 108 static void knote_drop(struct knote *kn); 109 static void knote_detach_and_drop(struct knote *kn); 110 static void knote_enqueue(struct knote *kn); 111 static void knote_dequeue(struct knote *kn); 112 static struct knote *knote_alloc(void); 113 static void knote_free(struct knote *kn); 114 115 static void filt_kqdetach(struct knote *kn); 116 static int filt_kqueue(struct knote *kn, long hint); 117 static int filt_procattach(struct knote *kn); 118 static void filt_procdetach(struct knote *kn); 119 static int filt_proc(struct knote *kn, long hint); 120 static int filt_fileattach(struct knote *kn); 121 static void filt_timerexpire(void *knx); 122 static int filt_timerattach(struct knote *kn); 123 static void filt_timerdetach(struct knote *kn); 124 static int filt_timer(struct knote *kn, long hint); 125 static int filt_userattach(struct knote *kn); 126 static void filt_userdetach(struct knote *kn); 127 static int filt_user(struct knote *kn, long hint); 128 static void filt_usertouch(struct knote *kn, struct kevent *kev, 129 u_long type); 130 131 static struct filterops file_filtops = 132 { FILTEROP_ISFD, filt_fileattach, NULL, NULL }; 133 static struct filterops kqread_filtops = 134 { FILTEROP_ISFD, NULL, filt_kqdetach, filt_kqueue }; 135 static struct filterops proc_filtops = 136 { 0, filt_procattach, filt_procdetach, filt_proc }; 137 static struct filterops timer_filtops = 138 { 0, filt_timerattach, filt_timerdetach, filt_timer }; 139 static struct filterops user_filtops = 140 { 0, filt_userattach, filt_userdetach, filt_user }; 141 142 static int kq_ncallouts = 0; 143 static int kq_calloutmax = (4 * 1024); 144 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 145 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 146 static int kq_checkloop = 1000000; 147 SYSCTL_INT(_kern, OID_AUTO, kq_checkloop, CTLFLAG_RW, 148 &kq_checkloop, 0, "Maximum number of callouts allocated for kqueue"); 149 150 #define KNOTE_ACTIVATE(kn) do { \ 151 kn->kn_status |= KN_ACTIVE; \ 152 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 153 knote_enqueue(kn); \ 154 } while(0) 155 156 #define KN_HASHSIZE 64 /* XXX should be tunable */ 157 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 158 159 extern struct filterops aio_filtops; 160 extern struct filterops sig_filtops; 161 162 /* 163 * Table for for all system-defined filters. 164 */ 165 static struct filterops *sysfilt_ops[] = { 166 &file_filtops, /* EVFILT_READ */ 167 &file_filtops, /* EVFILT_WRITE */ 168 &aio_filtops, /* EVFILT_AIO */ 169 &file_filtops, /* EVFILT_VNODE */ 170 &proc_filtops, /* EVFILT_PROC */ 171 &sig_filtops, /* EVFILT_SIGNAL */ 172 &timer_filtops, /* EVFILT_TIMER */ 173 &file_filtops, /* EVFILT_EXCEPT */ 174 &user_filtops, /* EVFILT_USER */ 175 }; 176 177 static int 178 filt_fileattach(struct knote *kn) 179 { 180 return (fo_kqfilter(kn->kn_fp, kn)); 181 } 182 183 /* 184 * MPSAFE 185 */ 186 static int 187 kqueue_kqfilter(struct file *fp, struct knote *kn) 188 { 189 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 190 191 if (kn->kn_filter != EVFILT_READ) 192 return (EOPNOTSUPP); 193 194 kn->kn_fop = &kqread_filtops; 195 knote_insert(&kq->kq_kqinfo.ki_note, kn); 196 return (0); 197 } 198 199 static void 200 filt_kqdetach(struct knote *kn) 201 { 202 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 203 204 knote_remove(&kq->kq_kqinfo.ki_note, kn); 205 } 206 207 /*ARGSUSED*/ 208 static int 209 filt_kqueue(struct knote *kn, long hint) 210 { 211 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 212 213 kn->kn_data = kq->kq_count; 214 return (kn->kn_data > 0); 215 } 216 217 static int 218 filt_procattach(struct knote *kn) 219 { 220 struct proc *p; 221 int immediate; 222 223 immediate = 0; 224 p = pfind(kn->kn_id); 225 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 226 p = zpfind(kn->kn_id); 227 immediate = 1; 228 } 229 if (p == NULL) { 230 return (ESRCH); 231 } 232 if (!PRISON_CHECK(curthread->td_ucred, p->p_ucred)) { 233 if (p) 234 PRELE(p); 235 return (EACCES); 236 } 237 238 lwkt_gettoken(&p->p_token); 239 kn->kn_ptr.p_proc = p; 240 kn->kn_flags |= EV_CLEAR; /* automatically set */ 241 242 /* 243 * internal flag indicating registration done by kernel 244 */ 245 if (kn->kn_flags & EV_FLAG1) { 246 kn->kn_data = kn->kn_sdata; /* ppid */ 247 kn->kn_fflags = NOTE_CHILD; 248 kn->kn_flags &= ~EV_FLAG1; 249 } 250 251 knote_insert(&p->p_klist, kn); 252 253 /* 254 * Immediately activate any exit notes if the target process is a 255 * zombie. This is necessary to handle the case where the target 256 * process, e.g. a child, dies before the kevent is negistered. 257 */ 258 if (immediate && filt_proc(kn, NOTE_EXIT)) 259 KNOTE_ACTIVATE(kn); 260 lwkt_reltoken(&p->p_token); 261 PRELE(p); 262 263 return (0); 264 } 265 266 /* 267 * The knote may be attached to a different process, which may exit, 268 * leaving nothing for the knote to be attached to. So when the process 269 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 270 * it will be deleted when read out. However, as part of the knote deletion, 271 * this routine is called, so a check is needed to avoid actually performing 272 * a detach, because the original process does not exist any more. 273 */ 274 static void 275 filt_procdetach(struct knote *kn) 276 { 277 struct proc *p; 278 279 if (kn->kn_status & KN_DETACHED) 280 return; 281 p = kn->kn_ptr.p_proc; 282 knote_remove(&p->p_klist, kn); 283 } 284 285 static int 286 filt_proc(struct knote *kn, long hint) 287 { 288 u_int event; 289 290 /* 291 * mask off extra data 292 */ 293 event = (u_int)hint & NOTE_PCTRLMASK; 294 295 /* 296 * if the user is interested in this event, record it. 297 */ 298 if (kn->kn_sfflags & event) 299 kn->kn_fflags |= event; 300 301 /* 302 * Process is gone, so flag the event as finished. Detach the 303 * knote from the process now because the process will be poof, 304 * gone later on. 305 */ 306 if (event == NOTE_EXIT) { 307 struct proc *p = kn->kn_ptr.p_proc; 308 if ((kn->kn_status & KN_DETACHED) == 0) { 309 PHOLD(p); 310 knote_remove(&p->p_klist, kn); 311 kn->kn_status |= KN_DETACHED; 312 kn->kn_data = p->p_xstat; 313 kn->kn_ptr.p_proc = NULL; 314 PRELE(p); 315 } 316 kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT); 317 return (1); 318 } 319 320 /* 321 * process forked, and user wants to track the new process, 322 * so attach a new knote to it, and immediately report an 323 * event with the parent's pid. 324 */ 325 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) { 326 struct kevent kev; 327 int error; 328 329 /* 330 * register knote with new process. 331 */ 332 kev.ident = hint & NOTE_PDATAMASK; /* pid */ 333 kev.filter = kn->kn_filter; 334 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 335 kev.fflags = kn->kn_sfflags; 336 kev.data = kn->kn_id; /* parent */ 337 kev.udata = kn->kn_kevent.udata; /* preserve udata */ 338 error = kqueue_register(kn->kn_kq, &kev); 339 if (error) 340 kn->kn_fflags |= NOTE_TRACKERR; 341 } 342 343 return (kn->kn_fflags != 0); 344 } 345 346 /* 347 * The callout interlocks with callout_terminate() but can still 348 * race a deletion so if KN_DELETING is set we just don't touch 349 * the knote. 350 */ 351 static void 352 filt_timerexpire(void *knx) 353 { 354 struct lwkt_token *tok; 355 struct knote *kn = knx; 356 struct callout *calloutp; 357 struct timeval tv; 358 int tticks; 359 360 tok = lwkt_token_pool_lookup(kn->kn_kq); 361 lwkt_gettoken(tok); 362 if ((kn->kn_status & KN_DELETING) == 0) { 363 kn->kn_data++; 364 KNOTE_ACTIVATE(kn); 365 366 if ((kn->kn_flags & EV_ONESHOT) == 0) { 367 tv.tv_sec = kn->kn_sdata / 1000; 368 tv.tv_usec = (kn->kn_sdata % 1000) * 1000; 369 tticks = tvtohz_high(&tv); 370 calloutp = (struct callout *)kn->kn_hook; 371 callout_reset(calloutp, tticks, filt_timerexpire, kn); 372 } 373 } 374 lwkt_reltoken(tok); 375 } 376 377 /* 378 * data contains amount of time to sleep, in milliseconds 379 */ 380 static int 381 filt_timerattach(struct knote *kn) 382 { 383 struct callout *calloutp; 384 struct timeval tv; 385 int tticks; 386 387 if (kq_ncallouts >= kq_calloutmax) { 388 kn->kn_hook = NULL; 389 return (ENOMEM); 390 } 391 kq_ncallouts++; 392 393 tv.tv_sec = kn->kn_sdata / 1000; 394 tv.tv_usec = (kn->kn_sdata % 1000) * 1000; 395 tticks = tvtohz_high(&tv); 396 397 kn->kn_flags |= EV_CLEAR; /* automatically set */ 398 calloutp = kmalloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 399 callout_init(calloutp); 400 kn->kn_hook = (caddr_t)calloutp; 401 callout_reset(calloutp, tticks, filt_timerexpire, kn); 402 403 return (0); 404 } 405 406 /* 407 * This function is called with the knote flagged locked but it is 408 * still possible to race a callout event due to the callback blocking. 409 * We must call callout_terminate() instead of callout_stop() to deal 410 * with the race. 411 */ 412 static void 413 filt_timerdetach(struct knote *kn) 414 { 415 struct callout *calloutp; 416 417 calloutp = (struct callout *)kn->kn_hook; 418 callout_terminate(calloutp); 419 kfree(calloutp, M_KQUEUE); 420 kq_ncallouts--; 421 } 422 423 static int 424 filt_timer(struct knote *kn, long hint) 425 { 426 427 return (kn->kn_data != 0); 428 } 429 430 /* 431 * EVFILT_USER 432 */ 433 static int 434 filt_userattach(struct knote *kn) 435 { 436 kn->kn_hook = NULL; 437 if (kn->kn_fflags & NOTE_TRIGGER) 438 kn->kn_ptr.hookid = 1; 439 else 440 kn->kn_ptr.hookid = 0; 441 return 0; 442 } 443 444 /* 445 * This function is called with the knote flagged locked but it is 446 * still possible to race a callout event due to the callback blocking. 447 * We must call callout_terminate() instead of callout_stop() to deal 448 * with the race. 449 */ 450 static void 451 filt_userdetach(struct knote *kn) 452 { 453 /* nothing to do */ 454 } 455 456 static int 457 filt_user(struct knote *kn, long hint) 458 { 459 return (kn->kn_ptr.hookid); 460 } 461 462 static void 463 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 464 { 465 u_int ffctrl; 466 467 switch (type) { 468 case EVENT_REGISTER: 469 if (kev->fflags & NOTE_TRIGGER) 470 kn->kn_ptr.hookid = 1; 471 472 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 473 kev->fflags &= NOTE_FFLAGSMASK; 474 switch (ffctrl) { 475 case NOTE_FFNOP: 476 break; 477 478 case NOTE_FFAND: 479 kn->kn_sfflags &= kev->fflags; 480 break; 481 482 case NOTE_FFOR: 483 kn->kn_sfflags |= kev->fflags; 484 break; 485 486 case NOTE_FFCOPY: 487 kn->kn_sfflags = kev->fflags; 488 break; 489 490 default: 491 /* XXX Return error? */ 492 break; 493 } 494 kn->kn_sdata = kev->data; 495 496 /* 497 * This is not the correct use of EV_CLEAR in an event 498 * modification, it should have been passed as a NOTE instead. 499 * But we need to maintain compatibility with Apple & FreeBSD. 500 * 501 * Note however that EV_CLEAR can still be used when doing 502 * the initial registration of the event and works as expected 503 * (clears the event on reception). 504 */ 505 if (kev->flags & EV_CLEAR) { 506 kn->kn_ptr.hookid = 0; 507 kn->kn_data = 0; 508 kn->kn_fflags = 0; 509 } 510 break; 511 512 case EVENT_PROCESS: 513 *kev = kn->kn_kevent; 514 kev->fflags = kn->kn_sfflags; 515 kev->data = kn->kn_sdata; 516 if (kn->kn_flags & EV_CLEAR) { 517 kn->kn_ptr.hookid = 0; 518 /* kn_data, kn_fflags handled by parent */ 519 } 520 break; 521 522 default: 523 panic("filt_usertouch() - invalid type (%ld)", type); 524 break; 525 } 526 } 527 528 /* 529 * Acquire a knote, return non-zero on success, 0 on failure. 530 * 531 * If we cannot acquire the knote we sleep and return 0. The knote 532 * may be stale on return in this case and the caller must restart 533 * whatever loop they are in. 534 * 535 * Related kq token must be held. 536 */ 537 static __inline 538 int 539 knote_acquire(struct knote *kn) 540 { 541 if (kn->kn_status & KN_PROCESSING) { 542 kn->kn_status |= KN_WAITING | KN_REPROCESS; 543 tsleep(kn, 0, "kqepts", hz); 544 /* knote may be stale now */ 545 return(0); 546 } 547 kn->kn_status |= KN_PROCESSING; 548 return(1); 549 } 550 551 /* 552 * Release an acquired knote, clearing KN_PROCESSING and handling any 553 * KN_REPROCESS events. 554 * 555 * Caller must be holding the related kq token 556 * 557 * Non-zero is returned if the knote is destroyed or detached. 558 */ 559 static __inline 560 int 561 knote_release(struct knote *kn) 562 { 563 while (kn->kn_status & KN_REPROCESS) { 564 kn->kn_status &= ~KN_REPROCESS; 565 if (kn->kn_status & KN_WAITING) { 566 kn->kn_status &= ~KN_WAITING; 567 wakeup(kn); 568 } 569 if (kn->kn_status & KN_DELETING) { 570 knote_detach_and_drop(kn); 571 return(1); 572 /* NOT REACHED */ 573 } 574 if (filter_event(kn, 0)) 575 KNOTE_ACTIVATE(kn); 576 } 577 if (kn->kn_status & KN_DETACHED) { 578 kn->kn_status &= ~KN_PROCESSING; 579 return(1); 580 } else { 581 kn->kn_status &= ~KN_PROCESSING; 582 return(0); 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 if (kq->kq_knhash) { 623 hashdestroy(kq->kq_knhash, M_KQUEUE, kq->kq_knhashmask); 624 kq->kq_knhash = NULL; 625 kq->kq_knhashmask = 0; 626 } 627 lwkt_reltoken(tok); 628 } 629 630 /* 631 * MPSAFE 632 */ 633 int 634 sys_kqueue(struct kqueue_args *uap) 635 { 636 struct thread *td = curthread; 637 struct kqueue *kq; 638 struct file *fp; 639 int fd, error; 640 641 error = falloc(td->td_lwp, &fp, &fd); 642 if (error) 643 return (error); 644 fp->f_flag = FREAD | FWRITE; 645 fp->f_type = DTYPE_KQUEUE; 646 fp->f_ops = &kqueueops; 647 648 kq = kmalloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO); 649 kqueue_init(kq, td->td_proc->p_fd); 650 fp->f_data = kq; 651 652 fsetfd(kq->kq_fdp, fp, fd); 653 uap->sysmsg_result = fd; 654 fdrop(fp); 655 return (error); 656 } 657 658 /* 659 * Copy 'count' items into the destination list pointed to by uap->eventlist. 660 */ 661 static int 662 kevent_copyout(void *arg, struct kevent *kevp, int count, int *res) 663 { 664 struct kevent_copyin_args *kap; 665 int error; 666 667 kap = (struct kevent_copyin_args *)arg; 668 669 error = copyout(kevp, kap->ka->eventlist, count * sizeof(*kevp)); 670 if (error == 0) { 671 kap->ka->eventlist += count; 672 *res += count; 673 } else { 674 *res = -1; 675 } 676 677 return (error); 678 } 679 680 /* 681 * Copy at most 'max' items from the list pointed to by kap->changelist, 682 * return number of items in 'events'. 683 */ 684 static int 685 kevent_copyin(void *arg, struct kevent *kevp, int max, int *events) 686 { 687 struct kevent_copyin_args *kap; 688 int error, count; 689 690 kap = (struct kevent_copyin_args *)arg; 691 692 count = min(kap->ka->nchanges - kap->pchanges, max); 693 error = copyin(kap->ka->changelist, kevp, count * sizeof *kevp); 694 if (error == 0) { 695 kap->ka->changelist += count; 696 kap->pchanges += count; 697 *events = count; 698 } 699 700 return (error); 701 } 702 703 /* 704 * MPSAFE 705 */ 706 int 707 kern_kevent(struct kqueue *kq, int nevents, int *res, void *uap, 708 k_copyin_fn kevent_copyinfn, k_copyout_fn kevent_copyoutfn, 709 struct timespec *tsp_in) 710 { 711 struct kevent *kevp; 712 struct timespec *tsp; 713 int i, n, total, error, nerrors = 0; 714 int lres; 715 int limit = kq_checkloop; 716 struct kevent kev[KQ_NEVENTS]; 717 struct knote marker; 718 struct lwkt_token *tok; 719 720 if (tsp_in == NULL || tsp_in->tv_sec || tsp_in->tv_nsec) 721 atomic_set_int(&curthread->td_mpflags, TDF_MP_BATCH_DEMARC); 722 723 724 tsp = tsp_in; 725 *res = 0; 726 727 tok = lwkt_token_pool_lookup(kq); 728 lwkt_gettoken(tok); 729 for ( ;; ) { 730 n = 0; 731 error = kevent_copyinfn(uap, kev, KQ_NEVENTS, &n); 732 if (error) 733 goto done; 734 if (n == 0) 735 break; 736 for (i = 0; i < n; i++) { 737 kevp = &kev[i]; 738 kevp->flags &= ~EV_SYSFLAGS; 739 error = kqueue_register(kq, kevp); 740 741 /* 742 * If a registration returns an error we 743 * immediately post the error. The kevent() 744 * call itself will fail with the error if 745 * no space is available for posting. 746 * 747 * Such errors normally bypass the timeout/blocking 748 * code. However, if the copyoutfn function refuses 749 * to post the error (see sys_poll()), then we 750 * ignore it too. 751 */ 752 if (error) { 753 kevp->flags = EV_ERROR; 754 kevp->data = error; 755 lres = *res; 756 kevent_copyoutfn(uap, kevp, 1, res); 757 if (*res < 0) { 758 goto done; 759 } else if (lres != *res) { 760 nevents--; 761 nerrors++; 762 } 763 } 764 } 765 } 766 if (nerrors) { 767 error = 0; 768 goto done; 769 } 770 771 /* 772 * Acquire/wait for events - setup timeout 773 */ 774 if (tsp != NULL) { 775 struct timespec ats; 776 777 if (tsp->tv_sec || tsp->tv_nsec) { 778 getnanouptime(&ats); 779 timespecadd(tsp, &ats); /* tsp = target time */ 780 } 781 } 782 783 /* 784 * Loop as required. 785 * 786 * Collect as many events as we can. Sleeping on successive 787 * loops is disabled if copyoutfn has incremented (*res). 788 * 789 * The loop stops if an error occurs, all events have been 790 * scanned (the marker has been reached), or fewer than the 791 * maximum number of events is found. 792 * 793 * The copyoutfn function does not have to increment (*res) in 794 * order for the loop to continue. 795 * 796 * NOTE: doselect() usually passes 0x7FFFFFFF for nevents. 797 */ 798 total = 0; 799 error = 0; 800 marker.kn_filter = EVFILT_MARKER; 801 marker.kn_status = KN_PROCESSING; 802 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); 803 while ((n = nevents - total) > 0) { 804 if (n > KQ_NEVENTS) 805 n = KQ_NEVENTS; 806 807 /* 808 * If no events are pending sleep until timeout (if any) 809 * or an event occurs. 810 * 811 * After the sleep completes the marker is moved to the 812 * end of the list, making any received events available 813 * to our scan. 814 */ 815 if (kq->kq_count == 0 && *res == 0) { 816 error = kqueue_sleep(kq, tsp); 817 if (error) 818 break; 819 820 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); 821 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); 822 } 823 824 /* 825 * Process all received events 826 * Account for all non-spurious events in our total 827 */ 828 i = kqueue_scan(kq, kev, n, &marker); 829 if (i) { 830 lres = *res; 831 error = kevent_copyoutfn(uap, kev, i, res); 832 total += *res - lres; 833 if (error) 834 break; 835 } 836 if (limit && --limit == 0) 837 panic("kqueue: checkloop failed i=%d", i); 838 839 /* 840 * Normally when fewer events are returned than requested 841 * we can stop. However, if only spurious events were 842 * collected the copyout will not bump (*res) and we have 843 * to continue. 844 */ 845 if (i < n && *res) 846 break; 847 848 /* 849 * Deal with an edge case where spurious events can cause 850 * a loop to occur without moving the marker. This can 851 * prevent kqueue_scan() from picking up new events which 852 * race us. We must be sure to move the marker for this 853 * case. 854 * 855 * NOTE: We do not want to move the marker if events 856 * were scanned because normal kqueue operations 857 * may reactivate events. Moving the marker in 858 * that case could result in duplicates for the 859 * same event. 860 */ 861 if (i == 0) { 862 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); 863 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); 864 } 865 } 866 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); 867 868 /* Timeouts do not return EWOULDBLOCK. */ 869 if (error == EWOULDBLOCK) 870 error = 0; 871 872 done: 873 lwkt_reltoken(tok); 874 return (error); 875 } 876 877 /* 878 * MPALMOSTSAFE 879 */ 880 int 881 sys_kevent(struct kevent_args *uap) 882 { 883 struct thread *td = curthread; 884 struct proc *p = td->td_proc; 885 struct timespec ts, *tsp; 886 struct kqueue *kq; 887 struct file *fp = NULL; 888 struct kevent_copyin_args *kap, ka; 889 int error; 890 891 if (uap->timeout) { 892 error = copyin(uap->timeout, &ts, sizeof(ts)); 893 if (error) 894 return (error); 895 tsp = &ts; 896 } else { 897 tsp = NULL; 898 } 899 fp = holdfp(p->p_fd, uap->fd, -1); 900 if (fp == NULL) 901 return (EBADF); 902 if (fp->f_type != DTYPE_KQUEUE) { 903 fdrop(fp); 904 return (EBADF); 905 } 906 907 kq = (struct kqueue *)fp->f_data; 908 909 kap = &ka; 910 kap->ka = uap; 911 kap->pchanges = 0; 912 913 error = kern_kevent(kq, uap->nevents, &uap->sysmsg_result, kap, 914 kevent_copyin, kevent_copyout, tsp); 915 916 fdrop(fp); 917 918 return (error); 919 } 920 921 /* 922 * Caller must be holding the kq token 923 */ 924 int 925 kqueue_register(struct kqueue *kq, struct kevent *kev) 926 { 927 struct lwkt_token *tok; 928 struct filedesc *fdp = kq->kq_fdp; 929 struct filterops *fops; 930 struct file *fp = NULL; 931 struct knote *kn = NULL; 932 int error = 0; 933 934 if (kev->filter < 0) { 935 if (kev->filter + EVFILT_SYSCOUNT < 0) 936 return (EINVAL); 937 fops = sysfilt_ops[~kev->filter]; /* to 0-base index */ 938 } else { 939 /* 940 * XXX 941 * filter attach routine is responsible for insuring that 942 * the identifier can be attached to it. 943 */ 944 return (EINVAL); 945 } 946 947 tok = lwkt_token_pool_lookup(kq); 948 lwkt_gettoken(tok); 949 if (fops->f_flags & FILTEROP_ISFD) { 950 /* validate descriptor */ 951 fp = holdfp(fdp, kev->ident, -1); 952 if (fp == NULL) { 953 lwkt_reltoken(tok); 954 return (EBADF); 955 } 956 lwkt_getpooltoken(&fp->f_klist); 957 again1: 958 SLIST_FOREACH(kn, &fp->f_klist, kn_link) { 959 if (kn->kn_kq == kq && 960 kn->kn_filter == kev->filter && 961 kn->kn_id == kev->ident) { 962 if (knote_acquire(kn) == 0) 963 goto again1; 964 break; 965 } 966 } 967 lwkt_relpooltoken(&fp->f_klist); 968 } else { 969 if (kq->kq_knhashmask) { 970 struct klist *list; 971 972 list = &kq->kq_knhash[ 973 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 974 lwkt_getpooltoken(list); 975 again2: 976 SLIST_FOREACH(kn, list, kn_link) { 977 if (kn->kn_id == kev->ident && 978 kn->kn_filter == kev->filter) { 979 if (knote_acquire(kn) == 0) 980 goto again2; 981 break; 982 } 983 } 984 lwkt_relpooltoken(list); 985 } 986 } 987 988 /* 989 * NOTE: At this point if kn is non-NULL we will have acquired 990 * it and set KN_PROCESSING. 991 */ 992 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) { 993 error = ENOENT; 994 goto done; 995 } 996 997 /* 998 * kn now contains the matching knote, or NULL if no match 999 */ 1000 if (kev->flags & EV_ADD) { 1001 if (kn == NULL) { 1002 kn = knote_alloc(); 1003 if (kn == NULL) { 1004 error = ENOMEM; 1005 goto done; 1006 } 1007 kn->kn_fp = fp; 1008 kn->kn_kq = kq; 1009 kn->kn_fop = fops; 1010 1011 /* 1012 * apply reference count to knote structure, and 1013 * do not release it at the end of this routine. 1014 */ 1015 fp = NULL; 1016 1017 kn->kn_sfflags = kev->fflags; 1018 kn->kn_sdata = kev->data; 1019 kev->fflags = 0; 1020 kev->data = 0; 1021 kn->kn_kevent = *kev; 1022 1023 /* 1024 * KN_PROCESSING prevents the knote from getting 1025 * ripped out from under us while we are trying 1026 * to attach it, in case the attach blocks. 1027 */ 1028 kn->kn_status = KN_PROCESSING; 1029 knote_attach(kn); 1030 if ((error = filter_attach(kn)) != 0) { 1031 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1032 knote_drop(kn); 1033 goto done; 1034 } 1035 1036 /* 1037 * Interlock against close races which either tried 1038 * to remove our knote while we were blocked or missed 1039 * it entirely prior to our attachment. We do not 1040 * want to end up with a knote on a closed descriptor. 1041 */ 1042 if ((fops->f_flags & FILTEROP_ISFD) && 1043 checkfdclosed(fdp, kev->ident, kn->kn_fp)) { 1044 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1045 } 1046 } else { 1047 /* 1048 * The user may change some filter values after the 1049 * initial EV_ADD, but doing so will not reset any 1050 * filter which have already been triggered. 1051 */ 1052 KKASSERT(kn->kn_status & KN_PROCESSING); 1053 if (fops == &user_filtops) { 1054 filt_usertouch(kn, kev, EVENT_REGISTER); 1055 } else { 1056 kn->kn_sfflags = kev->fflags; 1057 kn->kn_sdata = kev->data; 1058 kn->kn_kevent.udata = kev->udata; 1059 } 1060 } 1061 1062 /* 1063 * Execute the filter event to immediately activate the 1064 * knote if necessary. If reprocessing events are pending 1065 * due to blocking above we do not run the filter here 1066 * but instead let knote_release() do it. Otherwise we 1067 * might run the filter on a deleted event. 1068 */ 1069 if ((kn->kn_status & KN_REPROCESS) == 0) { 1070 if (filter_event(kn, 0)) 1071 KNOTE_ACTIVATE(kn); 1072 } 1073 } else if (kev->flags & EV_DELETE) { 1074 /* 1075 * Delete the existing knote 1076 */ 1077 knote_detach_and_drop(kn); 1078 goto done; 1079 } else { 1080 /* 1081 * Modify an existing event. 1082 * 1083 * The user may change some filter values after the 1084 * initial EV_ADD, but doing so will not reset any 1085 * filter which have already been triggered. 1086 */ 1087 KKASSERT(kn->kn_status & KN_PROCESSING); 1088 if (fops == &user_filtops) { 1089 filt_usertouch(kn, kev, EVENT_REGISTER); 1090 } else { 1091 kn->kn_sfflags = kev->fflags; 1092 kn->kn_sdata = kev->data; 1093 kn->kn_kevent.udata = kev->udata; 1094 } 1095 1096 /* 1097 * Execute the filter event to immediately activate the 1098 * knote if necessary. If reprocessing events are pending 1099 * due to blocking above we do not run the filter here 1100 * but instead let knote_release() do it. Otherwise we 1101 * might run the filter on a deleted event. 1102 */ 1103 if ((kn->kn_status & KN_REPROCESS) == 0) { 1104 if (filter_event(kn, 0)) 1105 KNOTE_ACTIVATE(kn); 1106 } 1107 } 1108 1109 /* 1110 * Disablement does not deactivate a knote here. 1111 */ 1112 if ((kev->flags & EV_DISABLE) && 1113 ((kn->kn_status & KN_DISABLED) == 0)) { 1114 kn->kn_status |= KN_DISABLED; 1115 } 1116 1117 /* 1118 * Re-enablement may have to immediately enqueue an active knote. 1119 */ 1120 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1121 kn->kn_status &= ~KN_DISABLED; 1122 if ((kn->kn_status & KN_ACTIVE) && 1123 ((kn->kn_status & KN_QUEUED) == 0)) { 1124 knote_enqueue(kn); 1125 } 1126 } 1127 1128 /* 1129 * Handle any required reprocessing 1130 */ 1131 knote_release(kn); 1132 /* kn may be invalid now */ 1133 1134 done: 1135 lwkt_reltoken(tok); 1136 if (fp != NULL) 1137 fdrop(fp); 1138 return (error); 1139 } 1140 1141 /* 1142 * Block as necessary until the target time is reached. 1143 * If tsp is NULL we block indefinitely. If tsp->ts_secs/nsecs are both 1144 * 0 we do not block at all. 1145 * 1146 * Caller must be holding the kq token. 1147 */ 1148 static int 1149 kqueue_sleep(struct kqueue *kq, struct timespec *tsp) 1150 { 1151 int error = 0; 1152 1153 if (tsp == NULL) { 1154 kq->kq_state |= KQ_SLEEP; 1155 error = tsleep(kq, PCATCH, "kqread", 0); 1156 } else if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) { 1157 error = EWOULDBLOCK; 1158 } else { 1159 struct timespec ats; 1160 struct timespec atx = *tsp; 1161 int timeout; 1162 1163 getnanouptime(&ats); 1164 timespecsub(&atx, &ats); 1165 if (ats.tv_sec < 0) { 1166 error = EWOULDBLOCK; 1167 } else { 1168 timeout = atx.tv_sec > 24 * 60 * 60 ? 1169 24 * 60 * 60 * hz : tstohz_high(&atx); 1170 kq->kq_state |= KQ_SLEEP; 1171 error = tsleep(kq, PCATCH, "kqread", timeout); 1172 } 1173 } 1174 1175 /* don't restart after signals... */ 1176 if (error == ERESTART) 1177 return (EINTR); 1178 1179 return (error); 1180 } 1181 1182 /* 1183 * Scan the kqueue, return the number of active events placed in kevp up 1184 * to count. 1185 * 1186 * Continuous mode events may get recycled, do not continue scanning past 1187 * marker unless no events have been collected. 1188 * 1189 * Caller must be holding the kq token 1190 */ 1191 static int 1192 kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, 1193 struct knote *marker) 1194 { 1195 struct knote *kn, local_marker; 1196 int total; 1197 1198 total = 0; 1199 local_marker.kn_filter = EVFILT_MARKER; 1200 local_marker.kn_status = KN_PROCESSING; 1201 1202 /* 1203 * Collect events. 1204 */ 1205 TAILQ_INSERT_HEAD(&kq->kq_knpend, &local_marker, kn_tqe); 1206 while (count) { 1207 kn = TAILQ_NEXT(&local_marker, kn_tqe); 1208 if (kn->kn_filter == EVFILT_MARKER) { 1209 /* Marker reached, we are done */ 1210 if (kn == marker) 1211 break; 1212 1213 /* Move local marker past some other threads marker */ 1214 kn = TAILQ_NEXT(kn, kn_tqe); 1215 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); 1216 TAILQ_INSERT_BEFORE(kn, &local_marker, kn_tqe); 1217 continue; 1218 } 1219 1220 /* 1221 * We can't skip a knote undergoing processing, otherwise 1222 * we risk not returning it when the user process expects 1223 * it should be returned. Sleep and retry. 1224 */ 1225 if (knote_acquire(kn) == 0) 1226 continue; 1227 1228 /* 1229 * Remove the event for processing. 1230 * 1231 * WARNING! We must leave KN_QUEUED set to prevent the 1232 * event from being KNOTE_ACTIVATE()d while 1233 * the queue state is in limbo, in case we 1234 * block. 1235 * 1236 * WARNING! We must set KN_PROCESSING to avoid races 1237 * against deletion or another thread's 1238 * processing. 1239 */ 1240 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); 1241 kq->kq_count--; 1242 1243 /* 1244 * We have to deal with an extremely important race against 1245 * file descriptor close()s here. The file descriptor can 1246 * disappear MPSAFE, and there is a small window of 1247 * opportunity between that and the call to knote_fdclose(). 1248 * 1249 * If we hit that window here while doselect or dopoll is 1250 * trying to delete a spurious event they will not be able 1251 * to match up the event against a knote and will go haywire. 1252 */ 1253 if ((kn->kn_fop->f_flags & FILTEROP_ISFD) && 1254 checkfdclosed(kq->kq_fdp, kn->kn_kevent.ident, kn->kn_fp)) { 1255 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1256 } 1257 1258 if (kn->kn_status & KN_DISABLED) { 1259 /* 1260 * If disabled we ensure the event is not queued 1261 * but leave its active bit set. On re-enablement 1262 * the event may be immediately triggered. 1263 */ 1264 kn->kn_status &= ~KN_QUEUED; 1265 } else if ((kn->kn_flags & EV_ONESHOT) == 0 && 1266 (kn->kn_status & KN_DELETING) == 0 && 1267 filter_event(kn, 0) == 0) { 1268 /* 1269 * If not running in one-shot mode and the event 1270 * is no longer present we ensure it is removed 1271 * from the queue and ignore it. 1272 */ 1273 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1274 } else { 1275 /* 1276 * Post the event 1277 */ 1278 if (kn->kn_fop == &user_filtops) 1279 filt_usertouch(kn, kevp, EVENT_PROCESS); 1280 else 1281 *kevp = kn->kn_kevent; 1282 ++kevp; 1283 ++total; 1284 --count; 1285 1286 if (kn->kn_flags & EV_ONESHOT) { 1287 kn->kn_status &= ~KN_QUEUED; 1288 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1289 } else { 1290 if (kn->kn_flags & EV_CLEAR) { 1291 kn->kn_data = 0; 1292 kn->kn_fflags = 0; 1293 kn->kn_status &= ~(KN_QUEUED | 1294 KN_ACTIVE); 1295 } else { 1296 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); 1297 kq->kq_count++; 1298 } 1299 } 1300 } 1301 1302 /* 1303 * Handle any post-processing states 1304 */ 1305 knote_release(kn); 1306 } 1307 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); 1308 1309 return (total); 1310 } 1311 1312 /* 1313 * XXX 1314 * This could be expanded to call kqueue_scan, if desired. 1315 * 1316 * MPSAFE 1317 */ 1318 static int 1319 kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags) 1320 { 1321 return (ENXIO); 1322 } 1323 1324 /* 1325 * MPSAFE 1326 */ 1327 static int 1328 kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags) 1329 { 1330 return (ENXIO); 1331 } 1332 1333 /* 1334 * MPALMOSTSAFE 1335 */ 1336 static int 1337 kqueue_ioctl(struct file *fp, u_long com, caddr_t data, 1338 struct ucred *cred, struct sysmsg *msg) 1339 { 1340 struct lwkt_token *tok; 1341 struct kqueue *kq; 1342 int error; 1343 1344 kq = (struct kqueue *)fp->f_data; 1345 tok = lwkt_token_pool_lookup(kq); 1346 lwkt_gettoken(tok); 1347 1348 switch(com) { 1349 case FIOASYNC: 1350 if (*(int *)data) 1351 kq->kq_state |= KQ_ASYNC; 1352 else 1353 kq->kq_state &= ~KQ_ASYNC; 1354 error = 0; 1355 break; 1356 case FIOSETOWN: 1357 error = fsetown(*(int *)data, &kq->kq_sigio); 1358 break; 1359 default: 1360 error = ENOTTY; 1361 break; 1362 } 1363 lwkt_reltoken(tok); 1364 return (error); 1365 } 1366 1367 /* 1368 * MPSAFE 1369 */ 1370 static int 1371 kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred) 1372 { 1373 struct kqueue *kq = (struct kqueue *)fp->f_data; 1374 1375 bzero((void *)st, sizeof(*st)); 1376 st->st_size = kq->kq_count; 1377 st->st_blksize = sizeof(struct kevent); 1378 st->st_mode = S_IFIFO; 1379 return (0); 1380 } 1381 1382 /* 1383 * MPSAFE 1384 */ 1385 static int 1386 kqueue_close(struct file *fp) 1387 { 1388 struct kqueue *kq = (struct kqueue *)fp->f_data; 1389 1390 kqueue_terminate(kq); 1391 1392 fp->f_data = NULL; 1393 funsetown(&kq->kq_sigio); 1394 1395 kfree(kq, M_KQUEUE); 1396 return (0); 1397 } 1398 1399 static void 1400 kqueue_wakeup(struct kqueue *kq) 1401 { 1402 if (kq->kq_state & KQ_SLEEP) { 1403 kq->kq_state &= ~KQ_SLEEP; 1404 wakeup(kq); 1405 } 1406 KNOTE(&kq->kq_kqinfo.ki_note, 0); 1407 } 1408 1409 /* 1410 * Calls filterops f_attach function, acquiring mplock if filter is not 1411 * marked as FILTEROP_MPSAFE. 1412 * 1413 * Caller must be holding the related kq token 1414 */ 1415 static int 1416 filter_attach(struct knote *kn) 1417 { 1418 int ret; 1419 1420 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { 1421 ret = kn->kn_fop->f_attach(kn); 1422 } else { 1423 get_mplock(); 1424 ret = kn->kn_fop->f_attach(kn); 1425 rel_mplock(); 1426 } 1427 return (ret); 1428 } 1429 1430 /* 1431 * Detach the knote and drop it, destroying the knote. 1432 * 1433 * Calls filterops f_detach function, acquiring mplock if filter is not 1434 * marked as FILTEROP_MPSAFE. 1435 * 1436 * Caller must be holding the related kq token 1437 */ 1438 static void 1439 knote_detach_and_drop(struct knote *kn) 1440 { 1441 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1442 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { 1443 kn->kn_fop->f_detach(kn); 1444 } else { 1445 get_mplock(); 1446 kn->kn_fop->f_detach(kn); 1447 rel_mplock(); 1448 } 1449 knote_drop(kn); 1450 } 1451 1452 /* 1453 * Calls filterops f_event function, acquiring mplock if filter is not 1454 * marked as FILTEROP_MPSAFE. 1455 * 1456 * If the knote is in the middle of being created or deleted we cannot 1457 * safely call the filter op. 1458 * 1459 * Caller must be holding the related kq token 1460 */ 1461 static int 1462 filter_event(struct knote *kn, long hint) 1463 { 1464 int ret; 1465 1466 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { 1467 ret = kn->kn_fop->f_event(kn, hint); 1468 } else { 1469 get_mplock(); 1470 ret = kn->kn_fop->f_event(kn, hint); 1471 rel_mplock(); 1472 } 1473 return (ret); 1474 } 1475 1476 /* 1477 * Walk down a list of knotes, activating them if their event has triggered. 1478 * 1479 * If we encounter any knotes which are undergoing processing we just mark 1480 * them for reprocessing and do not try to [re]activate the knote. However, 1481 * if a hint is being passed we have to wait and that makes things a bit 1482 * sticky. 1483 */ 1484 void 1485 knote(struct klist *list, long hint) 1486 { 1487 struct kqueue *kq; 1488 struct knote *kn; 1489 struct knote *kntmp; 1490 1491 lwkt_getpooltoken(list); 1492 restart: 1493 SLIST_FOREACH(kn, list, kn_next) { 1494 kq = kn->kn_kq; 1495 lwkt_getpooltoken(kq); 1496 1497 /* temporary verification hack */ 1498 SLIST_FOREACH(kntmp, list, kn_next) { 1499 if (kn == kntmp) 1500 break; 1501 } 1502 if (kn != kntmp || kn->kn_kq != kq) { 1503 lwkt_relpooltoken(kq); 1504 goto restart; 1505 } 1506 1507 if (kn->kn_status & KN_PROCESSING) { 1508 /* 1509 * Someone else is processing the knote, ask the 1510 * other thread to reprocess it and don't mess 1511 * with it otherwise. 1512 */ 1513 if (hint == 0) { 1514 kn->kn_status |= KN_REPROCESS; 1515 lwkt_relpooltoken(kq); 1516 continue; 1517 } 1518 1519 /* 1520 * If the hint is non-zero we have to wait or risk 1521 * losing the state the caller is trying to update. 1522 * 1523 * XXX This is a real problem, certain process 1524 * and signal filters will bump kn_data for 1525 * already-processed notes more than once if 1526 * we restart the list scan. FIXME. 1527 */ 1528 kn->kn_status |= KN_WAITING | KN_REPROCESS; 1529 tsleep(kn, 0, "knotec", hz); 1530 lwkt_relpooltoken(kq); 1531 goto restart; 1532 } 1533 1534 /* 1535 * Become the reprocessing master ourselves. 1536 * 1537 * If hint is non-zer running the event is mandatory 1538 * when not deleting so do it whether reprocessing is 1539 * set or not. 1540 */ 1541 kn->kn_status |= KN_PROCESSING; 1542 if ((kn->kn_status & KN_DELETING) == 0) { 1543 if (filter_event(kn, hint)) 1544 KNOTE_ACTIVATE(kn); 1545 } 1546 if (knote_release(kn)) { 1547 lwkt_relpooltoken(kq); 1548 goto restart; 1549 } 1550 lwkt_relpooltoken(kq); 1551 } 1552 lwkt_relpooltoken(list); 1553 } 1554 1555 /* 1556 * Insert knote at head of klist. 1557 * 1558 * This function may only be called via a filter function and thus 1559 * kq_token should already be held and marked for processing. 1560 */ 1561 void 1562 knote_insert(struct klist *klist, struct knote *kn) 1563 { 1564 lwkt_getpooltoken(klist); 1565 KKASSERT(kn->kn_status & KN_PROCESSING); 1566 SLIST_INSERT_HEAD(klist, kn, kn_next); 1567 lwkt_relpooltoken(klist); 1568 } 1569 1570 /* 1571 * Remove knote from a klist 1572 * 1573 * This function may only be called via a filter function and thus 1574 * kq_token should already be held and marked for processing. 1575 */ 1576 void 1577 knote_remove(struct klist *klist, struct knote *kn) 1578 { 1579 lwkt_getpooltoken(klist); 1580 KKASSERT(kn->kn_status & KN_PROCESSING); 1581 SLIST_REMOVE(klist, kn, knote, kn_next); 1582 lwkt_relpooltoken(klist); 1583 } 1584 1585 #if 0 1586 /* 1587 * Remove all knotes from a specified klist 1588 * 1589 * Only called from aio. 1590 */ 1591 void 1592 knote_empty(struct klist *list) 1593 { 1594 struct knote *kn; 1595 1596 lwkt_gettoken(&kq_token); 1597 while ((kn = SLIST_FIRST(list)) != NULL) { 1598 if (knote_acquire(kn)) 1599 knote_detach_and_drop(kn); 1600 } 1601 lwkt_reltoken(&kq_token); 1602 } 1603 #endif 1604 1605 void 1606 knote_assume_knotes(struct kqinfo *src, struct kqinfo *dst, 1607 struct filterops *ops, void *hook) 1608 { 1609 struct kqueue *kq; 1610 struct knote *kn; 1611 1612 lwkt_getpooltoken(&src->ki_note); 1613 lwkt_getpooltoken(&dst->ki_note); 1614 while ((kn = SLIST_FIRST(&src->ki_note)) != NULL) { 1615 kq = kn->kn_kq; 1616 lwkt_getpooltoken(kq); 1617 if (SLIST_FIRST(&src->ki_note) != kn || kn->kn_kq != kq) { 1618 lwkt_relpooltoken(kq); 1619 continue; 1620 } 1621 if (knote_acquire(kn)) { 1622 knote_remove(&src->ki_note, kn); 1623 kn->kn_fop = ops; 1624 kn->kn_hook = hook; 1625 knote_insert(&dst->ki_note, kn); 1626 knote_release(kn); 1627 /* kn may be invalid now */ 1628 } 1629 lwkt_relpooltoken(kq); 1630 } 1631 lwkt_relpooltoken(&dst->ki_note); 1632 lwkt_relpooltoken(&src->ki_note); 1633 } 1634 1635 /* 1636 * Remove all knotes referencing a specified fd 1637 */ 1638 void 1639 knote_fdclose(struct file *fp, struct filedesc *fdp, int fd) 1640 { 1641 struct kqueue *kq; 1642 struct knote *kn; 1643 struct knote *kntmp; 1644 1645 lwkt_getpooltoken(&fp->f_klist); 1646 restart: 1647 SLIST_FOREACH(kn, &fp->f_klist, kn_link) { 1648 if (kn->kn_kq->kq_fdp == fdp && kn->kn_id == fd) { 1649 kq = kn->kn_kq; 1650 lwkt_getpooltoken(kq); 1651 1652 /* temporary verification hack */ 1653 SLIST_FOREACH(kntmp, &fp->f_klist, kn_link) { 1654 if (kn == kntmp) 1655 break; 1656 } 1657 if (kn != kntmp || kn->kn_kq->kq_fdp != fdp || 1658 kn->kn_id != fd || kn->kn_kq != kq) { 1659 lwkt_relpooltoken(kq); 1660 goto restart; 1661 } 1662 if (knote_acquire(kn)) 1663 knote_detach_and_drop(kn); 1664 lwkt_relpooltoken(kq); 1665 goto restart; 1666 } 1667 } 1668 lwkt_relpooltoken(&fp->f_klist); 1669 } 1670 1671 /* 1672 * Low level attach function. 1673 * 1674 * The knote should already be marked for processing. 1675 * Caller must hold the related kq token. 1676 */ 1677 static void 1678 knote_attach(struct knote *kn) 1679 { 1680 struct klist *list; 1681 struct kqueue *kq = kn->kn_kq; 1682 1683 if (kn->kn_fop->f_flags & FILTEROP_ISFD) { 1684 KKASSERT(kn->kn_fp); 1685 list = &kn->kn_fp->f_klist; 1686 } else { 1687 if (kq->kq_knhashmask == 0) 1688 kq->kq_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1689 &kq->kq_knhashmask); 1690 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1691 } 1692 lwkt_getpooltoken(list); 1693 SLIST_INSERT_HEAD(list, kn, kn_link); 1694 TAILQ_INSERT_HEAD(&kq->kq_knlist, kn, kn_kqlink); 1695 lwkt_relpooltoken(list); 1696 } 1697 1698 /* 1699 * Low level drop function. 1700 * 1701 * The knote should already be marked for processing. 1702 * Caller must hold the related kq token. 1703 */ 1704 static void 1705 knote_drop(struct knote *kn) 1706 { 1707 struct kqueue *kq; 1708 struct klist *list; 1709 1710 kq = kn->kn_kq; 1711 1712 if (kn->kn_fop->f_flags & FILTEROP_ISFD) 1713 list = &kn->kn_fp->f_klist; 1714 else 1715 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1716 1717 lwkt_getpooltoken(list); 1718 SLIST_REMOVE(list, kn, knote, kn_link); 1719 TAILQ_REMOVE(&kq->kq_knlist, kn, kn_kqlink); 1720 if (kn->kn_status & KN_QUEUED) 1721 knote_dequeue(kn); 1722 if (kn->kn_fop->f_flags & FILTEROP_ISFD) { 1723 fdrop(kn->kn_fp); 1724 kn->kn_fp = NULL; 1725 } 1726 knote_free(kn); 1727 lwkt_relpooltoken(list); 1728 } 1729 1730 /* 1731 * Low level enqueue function. 1732 * 1733 * The knote should already be marked for processing. 1734 * Caller must be holding the kq token 1735 */ 1736 static void 1737 knote_enqueue(struct knote *kn) 1738 { 1739 struct kqueue *kq = kn->kn_kq; 1740 1741 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 1742 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); 1743 kn->kn_status |= KN_QUEUED; 1744 ++kq->kq_count; 1745 1746 /* 1747 * Send SIGIO on request (typically set up as a mailbox signal) 1748 */ 1749 if (kq->kq_sigio && (kq->kq_state & KQ_ASYNC) && kq->kq_count == 1) 1750 pgsigio(kq->kq_sigio, SIGIO, 0); 1751 1752 kqueue_wakeup(kq); 1753 } 1754 1755 /* 1756 * Low level dequeue function. 1757 * 1758 * The knote should already be marked for processing. 1759 * Caller must be holding the kq token 1760 */ 1761 static void 1762 knote_dequeue(struct knote *kn) 1763 { 1764 struct kqueue *kq = kn->kn_kq; 1765 1766 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 1767 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); 1768 kn->kn_status &= ~KN_QUEUED; 1769 kq->kq_count--; 1770 } 1771 1772 static struct knote * 1773 knote_alloc(void) 1774 { 1775 return kmalloc(sizeof(struct knote), M_KQUEUE, M_WAITOK); 1776 } 1777 1778 static void 1779 knote_free(struct knote *kn) 1780 { 1781 kfree(kn, M_KQUEUE); 1782 } 1783