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_scan(struct kqueue *kq, struct kevent *kevp, int count, 78 struct knote *marker); 79 static int kqueue_read(struct file *fp, struct uio *uio, 80 struct ucred *cred, int flags); 81 static int kqueue_write(struct file *fp, struct uio *uio, 82 struct ucred *cred, int flags); 83 static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data, 84 struct ucred *cred, struct sysmsg *msg); 85 static int kqueue_kqfilter(struct file *fp, struct knote *kn); 86 static int kqueue_stat(struct file *fp, struct stat *st, 87 struct ucred *cred); 88 static int kqueue_close(struct file *fp); 89 static void kqueue_wakeup(struct kqueue *kq); 90 static int filter_attach(struct knote *kn); 91 static int filter_event(struct knote *kn, long hint); 92 93 /* 94 * MPSAFE 95 */ 96 static struct fileops kqueueops = { 97 .fo_read = kqueue_read, 98 .fo_write = kqueue_write, 99 .fo_ioctl = kqueue_ioctl, 100 .fo_kqfilter = kqueue_kqfilter, 101 .fo_stat = kqueue_stat, 102 .fo_close = kqueue_close, 103 .fo_shutdown = nofo_shutdown 104 }; 105 106 static void knote_attach(struct knote *kn); 107 static void knote_drop(struct knote *kn); 108 static void knote_detach_and_drop(struct knote *kn); 109 static void knote_enqueue(struct knote *kn); 110 static void knote_dequeue(struct knote *kn); 111 static struct knote *knote_alloc(void); 112 static void knote_free(struct knote *kn); 113 114 static void filt_kqdetach(struct knote *kn); 115 static int filt_kqueue(struct knote *kn, long hint); 116 static int filt_procattach(struct knote *kn); 117 static void filt_procdetach(struct knote *kn); 118 static int filt_proc(struct knote *kn, long hint); 119 static int filt_fileattach(struct knote *kn); 120 static void filt_timerexpire(void *knx); 121 static int filt_timerattach(struct knote *kn); 122 static void filt_timerdetach(struct knote *kn); 123 static int filt_timer(struct knote *kn, long hint); 124 static int filt_userattach(struct knote *kn); 125 static void filt_userdetach(struct knote *kn); 126 static int filt_user(struct knote *kn, long hint); 127 static void filt_usertouch(struct knote *kn, struct kevent *kev, 128 u_long type); 129 130 static struct filterops file_filtops = 131 { FILTEROP_ISFD | FILTEROP_MPSAFE, filt_fileattach, NULL, NULL }; 132 static struct filterops kqread_filtops = 133 { FILTEROP_ISFD | FILTEROP_MPSAFE, NULL, filt_kqdetach, filt_kqueue }; 134 static struct filterops proc_filtops = 135 { 0, filt_procattach, filt_procdetach, filt_proc }; 136 static struct filterops timer_filtops = 137 { FILTEROP_MPSAFE, filt_timerattach, filt_timerdetach, filt_timer }; 138 static struct filterops user_filtops = 139 { 0, filt_userattach, filt_userdetach, filt_user }; 140 141 static int kq_ncallouts = 0; 142 static int kq_calloutmax = (4 * 1024); 143 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 144 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 145 static int kq_checkloop = 1000000; 146 SYSCTL_INT(_kern, OID_AUTO, kq_checkloop, CTLFLAG_RW, 147 &kq_checkloop, 0, "Maximum number of callouts allocated for kqueue"); 148 149 #define KNOTE_ACTIVATE(kn) do { \ 150 kn->kn_status |= KN_ACTIVE; \ 151 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 152 knote_enqueue(kn); \ 153 } while(0) 154 155 #define KN_HASHSIZE 64 /* XXX should be tunable */ 156 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 157 158 extern struct filterops aio_filtops; 159 extern struct filterops sig_filtops; 160 161 /* 162 * Table for for all system-defined filters. 163 */ 164 static struct filterops *sysfilt_ops[] = { 165 &file_filtops, /* EVFILT_READ */ 166 &file_filtops, /* EVFILT_WRITE */ 167 &aio_filtops, /* EVFILT_AIO */ 168 &file_filtops, /* EVFILT_VNODE */ 169 &proc_filtops, /* EVFILT_PROC */ 170 &sig_filtops, /* EVFILT_SIGNAL */ 171 &timer_filtops, /* EVFILT_TIMER */ 172 &file_filtops, /* EVFILT_EXCEPT */ 173 &user_filtops, /* EVFILT_USER */ 174 }; 175 176 static int 177 filt_fileattach(struct knote *kn) 178 { 179 return (fo_kqfilter(kn->kn_fp, kn)); 180 } 181 182 /* 183 * MPSAFE 184 */ 185 static int 186 kqueue_kqfilter(struct file *fp, struct knote *kn) 187 { 188 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 189 190 if (kn->kn_filter != EVFILT_READ) 191 return (EOPNOTSUPP); 192 193 kn->kn_fop = &kqread_filtops; 194 knote_insert(&kq->kq_kqinfo.ki_note, kn); 195 return (0); 196 } 197 198 static void 199 filt_kqdetach(struct knote *kn) 200 { 201 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 202 203 knote_remove(&kq->kq_kqinfo.ki_note, kn); 204 } 205 206 /*ARGSUSED*/ 207 static int 208 filt_kqueue(struct knote *kn, long hint) 209 { 210 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 211 212 kn->kn_data = kq->kq_count; 213 return (kn->kn_data > 0); 214 } 215 216 static int 217 filt_procattach(struct knote *kn) 218 { 219 struct proc *p; 220 int immediate; 221 222 immediate = 0; 223 p = pfind(kn->kn_id); 224 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 225 p = zpfind(kn->kn_id); 226 immediate = 1; 227 } 228 if (p == NULL) { 229 return (ESRCH); 230 } 231 if (!PRISON_CHECK(curthread->td_ucred, p->p_ucred)) { 232 if (p) 233 PRELE(p); 234 return (EACCES); 235 } 236 237 lwkt_gettoken(&p->p_token); 238 kn->kn_ptr.p_proc = p; 239 kn->kn_flags |= EV_CLEAR; /* automatically set */ 240 241 /* 242 * internal flag indicating registration done by kernel 243 */ 244 if (kn->kn_flags & EV_FLAG1) { 245 kn->kn_data = kn->kn_sdata; /* ppid */ 246 kn->kn_fflags = NOTE_CHILD; 247 kn->kn_flags &= ~EV_FLAG1; 248 } 249 250 knote_insert(&p->p_klist, kn); 251 252 /* 253 * Immediately activate any exit notes if the target process is a 254 * zombie. This is necessary to handle the case where the target 255 * process, e.g. a child, dies before the kevent is negistered. 256 */ 257 if (immediate && filt_proc(kn, NOTE_EXIT)) 258 KNOTE_ACTIVATE(kn); 259 lwkt_reltoken(&p->p_token); 260 PRELE(p); 261 262 return (0); 263 } 264 265 /* 266 * The knote may be attached to a different process, which may exit, 267 * leaving nothing for the knote to be attached to. So when the process 268 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 269 * it will be deleted when read out. However, as part of the knote deletion, 270 * this routine is called, so a check is needed to avoid actually performing 271 * a detach, because the original process does not exist any more. 272 */ 273 static void 274 filt_procdetach(struct knote *kn) 275 { 276 struct proc *p; 277 278 if (kn->kn_status & KN_DETACHED) 279 return; 280 p = kn->kn_ptr.p_proc; 281 knote_remove(&p->p_klist, kn); 282 } 283 284 static int 285 filt_proc(struct knote *kn, long hint) 286 { 287 u_int event; 288 289 /* 290 * mask off extra data 291 */ 292 event = (u_int)hint & NOTE_PCTRLMASK; 293 294 /* 295 * if the user is interested in this event, record it. 296 */ 297 if (kn->kn_sfflags & event) 298 kn->kn_fflags |= event; 299 300 /* 301 * Process is gone, so flag the event as finished. Detach the 302 * knote from the process now because the process will be poof, 303 * gone later on. 304 */ 305 if (event == NOTE_EXIT) { 306 struct proc *p = kn->kn_ptr.p_proc; 307 if ((kn->kn_status & KN_DETACHED) == 0) { 308 PHOLD(p); 309 knote_remove(&p->p_klist, kn); 310 kn->kn_status |= KN_DETACHED; 311 kn->kn_data = p->p_xstat; 312 kn->kn_ptr.p_proc = NULL; 313 PRELE(p); 314 } 315 kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT); 316 return (1); 317 } 318 319 /* 320 * process forked, and user wants to track the new process, 321 * so attach a new knote to it, and immediately report an 322 * event with the parent's pid. 323 */ 324 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) { 325 struct kevent kev; 326 int error; 327 328 /* 329 * register knote with new process. 330 */ 331 kev.ident = hint & NOTE_PDATAMASK; /* pid */ 332 kev.filter = kn->kn_filter; 333 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 334 kev.fflags = kn->kn_sfflags; 335 kev.data = kn->kn_id; /* parent */ 336 kev.udata = kn->kn_kevent.udata; /* preserve udata */ 337 error = kqueue_register(kn->kn_kq, &kev); 338 if (error) 339 kn->kn_fflags |= NOTE_TRACKERR; 340 } 341 342 return (kn->kn_fflags != 0); 343 } 344 345 /* 346 * The callout interlocks with callout_terminate() but can still 347 * race a deletion so if KN_DELETING is set we just don't touch 348 * the knote. 349 */ 350 static void 351 filt_timerexpire(void *knx) 352 { 353 struct lwkt_token *tok; 354 struct knote *kn = knx; 355 struct callout *calloutp; 356 struct timeval tv; 357 int tticks; 358 359 tok = lwkt_token_pool_lookup(kn->kn_kq); 360 lwkt_gettoken(tok); 361 if ((kn->kn_status & KN_DELETING) == 0) { 362 kn->kn_data++; 363 KNOTE_ACTIVATE(kn); 364 365 if ((kn->kn_flags & EV_ONESHOT) == 0) { 366 tv.tv_sec = kn->kn_sdata / 1000; 367 tv.tv_usec = (kn->kn_sdata % 1000) * 1000; 368 tticks = tvtohz_high(&tv); 369 calloutp = (struct callout *)kn->kn_hook; 370 callout_reset(calloutp, tticks, filt_timerexpire, kn); 371 } 372 } 373 lwkt_reltoken(tok); 374 } 375 376 /* 377 * data contains amount of time to sleep, in milliseconds 378 */ 379 static int 380 filt_timerattach(struct knote *kn) 381 { 382 struct callout *calloutp; 383 struct timeval tv; 384 int tticks; 385 int prev_ncallouts; 386 387 prev_ncallouts = atomic_fetchadd_int(&kq_ncallouts, 1); 388 if (prev_ncallouts >= kq_calloutmax) { 389 atomic_subtract_int(&kq_ncallouts, 1); 390 kn->kn_hook = NULL; 391 return (ENOMEM); 392 } 393 394 tv.tv_sec = kn->kn_sdata / 1000; 395 tv.tv_usec = (kn->kn_sdata % 1000) * 1000; 396 tticks = tvtohz_high(&tv); 397 398 kn->kn_flags |= EV_CLEAR; /* automatically set */ 399 calloutp = kmalloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 400 callout_init_mp(calloutp); 401 kn->kn_hook = (caddr_t)calloutp; 402 callout_reset(calloutp, tticks, filt_timerexpire, kn); 403 404 return (0); 405 } 406 407 /* 408 * This function is called with the knote flagged locked but it is 409 * still possible to race a callout event due to the callback blocking. 410 * We must call callout_terminate() instead of callout_stop() to deal 411 * with the race. 412 */ 413 static void 414 filt_timerdetach(struct knote *kn) 415 { 416 struct callout *calloutp; 417 418 calloutp = (struct callout *)kn->kn_hook; 419 callout_terminate(calloutp); 420 kfree(calloutp, M_KQUEUE); 421 atomic_subtract_int(&kq_ncallouts, 1); 422 } 423 424 static int 425 filt_timer(struct knote *kn, long hint) 426 { 427 428 return (kn->kn_data != 0); 429 } 430 431 /* 432 * EVFILT_USER 433 */ 434 static int 435 filt_userattach(struct knote *kn) 436 { 437 kn->kn_hook = NULL; 438 if (kn->kn_fflags & NOTE_TRIGGER) 439 kn->kn_ptr.hookid = 1; 440 else 441 kn->kn_ptr.hookid = 0; 442 return 0; 443 } 444 445 /* 446 * This function is called with the knote flagged locked but it is 447 * still possible to race a callout event due to the callback blocking. 448 * We must call callout_terminate() instead of callout_stop() to deal 449 * with the race. 450 */ 451 static void 452 filt_userdetach(struct knote *kn) 453 { 454 /* nothing to do */ 455 } 456 457 static int 458 filt_user(struct knote *kn, long hint) 459 { 460 return (kn->kn_ptr.hookid); 461 } 462 463 static void 464 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 465 { 466 u_int ffctrl; 467 468 switch (type) { 469 case EVENT_REGISTER: 470 if (kev->fflags & NOTE_TRIGGER) 471 kn->kn_ptr.hookid = 1; 472 473 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 474 kev->fflags &= NOTE_FFLAGSMASK; 475 switch (ffctrl) { 476 case NOTE_FFNOP: 477 break; 478 479 case NOTE_FFAND: 480 kn->kn_sfflags &= kev->fflags; 481 break; 482 483 case NOTE_FFOR: 484 kn->kn_sfflags |= kev->fflags; 485 break; 486 487 case NOTE_FFCOPY: 488 kn->kn_sfflags = kev->fflags; 489 break; 490 491 default: 492 /* XXX Return error? */ 493 break; 494 } 495 kn->kn_sdata = kev->data; 496 497 /* 498 * This is not the correct use of EV_CLEAR in an event 499 * modification, it should have been passed as a NOTE instead. 500 * But we need to maintain compatibility with Apple & FreeBSD. 501 * 502 * Note however that EV_CLEAR can still be used when doing 503 * the initial registration of the event and works as expected 504 * (clears the event on reception). 505 */ 506 if (kev->flags & EV_CLEAR) { 507 kn->kn_ptr.hookid = 0; 508 kn->kn_data = 0; 509 kn->kn_fflags = 0; 510 } 511 break; 512 513 case EVENT_PROCESS: 514 *kev = kn->kn_kevent; 515 kev->fflags = kn->kn_sfflags; 516 kev->data = kn->kn_sdata; 517 if (kn->kn_flags & EV_CLEAR) { 518 kn->kn_ptr.hookid = 0; 519 /* kn_data, kn_fflags handled by parent */ 520 } 521 break; 522 523 default: 524 panic("filt_usertouch() - invalid type (%ld)", type); 525 break; 526 } 527 } 528 529 /* 530 * Acquire a knote, return non-zero on success, 0 on failure. 531 * 532 * If we cannot acquire the knote we sleep and return 0. The knote 533 * may be stale on return in this case and the caller must restart 534 * whatever loop they are in. 535 * 536 * Related kq token must be held. 537 */ 538 static __inline 539 int 540 knote_acquire(struct knote *kn) 541 { 542 if (kn->kn_status & KN_PROCESSING) { 543 kn->kn_status |= KN_WAITING | KN_REPROCESS; 544 tsleep(kn, 0, "kqepts", hz); 545 /* knote may be stale now */ 546 return(0); 547 } 548 kn->kn_status |= KN_PROCESSING; 549 return(1); 550 } 551 552 /* 553 * Release an acquired knote, clearing KN_PROCESSING and handling any 554 * KN_REPROCESS events. 555 * 556 * Caller must be holding the related kq token 557 * 558 * Non-zero is returned if the knote is destroyed or detached. 559 */ 560 static __inline 561 int 562 knote_release(struct knote *kn) 563 { 564 while (kn->kn_status & KN_REPROCESS) { 565 kn->kn_status &= ~KN_REPROCESS; 566 if (kn->kn_status & KN_WAITING) { 567 kn->kn_status &= ~KN_WAITING; 568 wakeup(kn); 569 } 570 if (kn->kn_status & KN_DELETING) { 571 knote_detach_and_drop(kn); 572 return(1); 573 /* NOT REACHED */ 574 } 575 if (filter_event(kn, 0)) 576 KNOTE_ACTIVATE(kn); 577 } 578 if (kn->kn_status & KN_DETACHED) { 579 kn->kn_status &= ~KN_PROCESSING; 580 return(1); 581 } else { 582 kn->kn_status &= ~KN_PROCESSING; 583 return(0); 584 } 585 } 586 587 /* 588 * Initialize a kqueue. 589 * 590 * NOTE: The lwp/proc code initializes a kqueue for select/poll ops. 591 * 592 * MPSAFE 593 */ 594 void 595 kqueue_init(struct kqueue *kq, struct filedesc *fdp) 596 { 597 TAILQ_INIT(&kq->kq_knpend); 598 TAILQ_INIT(&kq->kq_knlist); 599 kq->kq_count = 0; 600 kq->kq_fdp = fdp; 601 SLIST_INIT(&kq->kq_kqinfo.ki_note); 602 } 603 604 /* 605 * Terminate a kqueue. Freeing the actual kq itself is left up to the 606 * caller (it might be embedded in a lwp so we don't do it here). 607 * 608 * The kq's knlist must be completely eradicated so block on any 609 * processing races. 610 */ 611 void 612 kqueue_terminate(struct kqueue *kq) 613 { 614 struct lwkt_token *tok; 615 struct knote *kn; 616 617 tok = lwkt_token_pool_lookup(kq); 618 lwkt_gettoken(tok); 619 while ((kn = TAILQ_FIRST(&kq->kq_knlist)) != NULL) { 620 if (knote_acquire(kn)) 621 knote_detach_and_drop(kn); 622 } 623 if (kq->kq_knhash) { 624 hashdestroy(kq->kq_knhash, M_KQUEUE, kq->kq_knhashmask); 625 kq->kq_knhash = NULL; 626 kq->kq_knhashmask = 0; 627 } 628 lwkt_reltoken(tok); 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 if (kn == NULL) { 1033 error = ENOMEM; 1034 goto done; 1035 } 1036 kn->kn_fp = fp; 1037 kn->kn_kq = kq; 1038 kn->kn_fop = fops; 1039 1040 /* 1041 * apply reference count to knote structure, and 1042 * do not release it at the end of this routine. 1043 */ 1044 fp = NULL; 1045 1046 kn->kn_sfflags = kev->fflags; 1047 kn->kn_sdata = kev->data; 1048 kev->fflags = 0; 1049 kev->data = 0; 1050 kn->kn_kevent = *kev; 1051 1052 /* 1053 * KN_PROCESSING prevents the knote from getting 1054 * ripped out from under us while we are trying 1055 * to attach it, in case the attach blocks. 1056 */ 1057 kn->kn_status = KN_PROCESSING; 1058 knote_attach(kn); 1059 if ((error = filter_attach(kn)) != 0) { 1060 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1061 knote_drop(kn); 1062 goto done; 1063 } 1064 1065 /* 1066 * Interlock against close races which either tried 1067 * to remove our knote while we were blocked or missed 1068 * it entirely prior to our attachment. We do not 1069 * want to end up with a knote on a closed descriptor. 1070 */ 1071 if ((fops->f_flags & FILTEROP_ISFD) && 1072 checkfdclosed(fdp, kev->ident, kn->kn_fp)) { 1073 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1074 } 1075 } else { 1076 /* 1077 * The user may change some filter values after the 1078 * initial EV_ADD, but doing so will not reset any 1079 * filter which have already been triggered. 1080 */ 1081 KKASSERT(kn->kn_status & KN_PROCESSING); 1082 if (fops == &user_filtops) { 1083 filt_usertouch(kn, kev, EVENT_REGISTER); 1084 } else { 1085 kn->kn_sfflags = kev->fflags; 1086 kn->kn_sdata = kev->data; 1087 kn->kn_kevent.udata = kev->udata; 1088 } 1089 } 1090 1091 /* 1092 * Execute the filter event to immediately activate the 1093 * knote if necessary. If reprocessing events are pending 1094 * due to blocking above we do not run the filter here 1095 * but instead let knote_release() do it. Otherwise we 1096 * might run the filter on a deleted event. 1097 */ 1098 if ((kn->kn_status & KN_REPROCESS) == 0) { 1099 if (filter_event(kn, 0)) 1100 KNOTE_ACTIVATE(kn); 1101 } 1102 } else if (kev->flags & EV_DELETE) { 1103 /* 1104 * Delete the existing knote 1105 */ 1106 knote_detach_and_drop(kn); 1107 goto done; 1108 } else { 1109 /* 1110 * Modify an existing event. 1111 * 1112 * The user may change some filter values after the 1113 * initial EV_ADD, but doing so will not reset any 1114 * filter which have already been triggered. 1115 */ 1116 KKASSERT(kn->kn_status & KN_PROCESSING); 1117 if (fops == &user_filtops) { 1118 filt_usertouch(kn, kev, EVENT_REGISTER); 1119 } else { 1120 kn->kn_sfflags = kev->fflags; 1121 kn->kn_sdata = kev->data; 1122 kn->kn_kevent.udata = kev->udata; 1123 } 1124 1125 /* 1126 * Execute the filter event to immediately activate the 1127 * knote if necessary. If reprocessing events are pending 1128 * due to blocking above we do not run the filter here 1129 * but instead let knote_release() do it. Otherwise we 1130 * might run the filter on a deleted event. 1131 */ 1132 if ((kn->kn_status & KN_REPROCESS) == 0) { 1133 if (filter_event(kn, 0)) 1134 KNOTE_ACTIVATE(kn); 1135 } 1136 } 1137 1138 /* 1139 * Disablement does not deactivate a knote here. 1140 */ 1141 if ((kev->flags & EV_DISABLE) && 1142 ((kn->kn_status & KN_DISABLED) == 0)) { 1143 kn->kn_status |= KN_DISABLED; 1144 } 1145 1146 /* 1147 * Re-enablement may have to immediately enqueue an active knote. 1148 */ 1149 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1150 kn->kn_status &= ~KN_DISABLED; 1151 if ((kn->kn_status & KN_ACTIVE) && 1152 ((kn->kn_status & KN_QUEUED) == 0)) { 1153 knote_enqueue(kn); 1154 } 1155 } 1156 1157 /* 1158 * Handle any required reprocessing 1159 */ 1160 knote_release(kn); 1161 /* kn may be invalid now */ 1162 1163 done: 1164 lwkt_reltoken(tok); 1165 if (fp != NULL) 1166 fdrop(fp); 1167 return (error); 1168 } 1169 1170 /* 1171 * Scan the kqueue, return the number of active events placed in kevp up 1172 * to count. 1173 * 1174 * Continuous mode events may get recycled, do not continue scanning past 1175 * marker unless no events have been collected. 1176 */ 1177 static int 1178 kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, 1179 struct knote *marker) 1180 { 1181 struct knote *kn, local_marker; 1182 int total; 1183 1184 total = 0; 1185 local_marker.kn_filter = EVFILT_MARKER; 1186 local_marker.kn_status = KN_PROCESSING; 1187 1188 lwkt_getpooltoken(kq); 1189 1190 /* 1191 * Collect events. 1192 */ 1193 TAILQ_INSERT_HEAD(&kq->kq_knpend, &local_marker, kn_tqe); 1194 while (count) { 1195 kn = TAILQ_NEXT(&local_marker, kn_tqe); 1196 if (kn->kn_filter == EVFILT_MARKER) { 1197 /* Marker reached, we are done */ 1198 if (kn == marker) 1199 break; 1200 1201 /* Move local marker past some other threads marker */ 1202 kn = TAILQ_NEXT(kn, kn_tqe); 1203 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); 1204 TAILQ_INSERT_BEFORE(kn, &local_marker, kn_tqe); 1205 continue; 1206 } 1207 1208 /* 1209 * We can't skip a knote undergoing processing, otherwise 1210 * we risk not returning it when the user process expects 1211 * it should be returned. Sleep and retry. 1212 */ 1213 if (knote_acquire(kn) == 0) 1214 continue; 1215 1216 /* 1217 * Remove the event for processing. 1218 * 1219 * WARNING! We must leave KN_QUEUED set to prevent the 1220 * event from being KNOTE_ACTIVATE()d while 1221 * the queue state is in limbo, in case we 1222 * block. 1223 * 1224 * WARNING! We must set KN_PROCESSING to avoid races 1225 * against deletion or another thread's 1226 * processing. 1227 */ 1228 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); 1229 kq->kq_count--; 1230 1231 /* 1232 * We have to deal with an extremely important race against 1233 * file descriptor close()s here. The file descriptor can 1234 * disappear MPSAFE, and there is a small window of 1235 * opportunity between that and the call to knote_fdclose(). 1236 * 1237 * If we hit that window here while doselect or dopoll is 1238 * trying to delete a spurious event they will not be able 1239 * to match up the event against a knote and will go haywire. 1240 */ 1241 if ((kn->kn_fop->f_flags & FILTEROP_ISFD) && 1242 checkfdclosed(kq->kq_fdp, kn->kn_kevent.ident, kn->kn_fp)) { 1243 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1244 } 1245 1246 if (kn->kn_status & KN_DISABLED) { 1247 /* 1248 * If disabled we ensure the event is not queued 1249 * but leave its active bit set. On re-enablement 1250 * the event may be immediately triggered. 1251 */ 1252 kn->kn_status &= ~KN_QUEUED; 1253 } else if ((kn->kn_flags & EV_ONESHOT) == 0 && 1254 (kn->kn_status & KN_DELETING) == 0 && 1255 filter_event(kn, 0) == 0) { 1256 /* 1257 * If not running in one-shot mode and the event 1258 * is no longer present we ensure it is removed 1259 * from the queue and ignore it. 1260 */ 1261 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1262 } else { 1263 /* 1264 * Post the event 1265 */ 1266 if (kn->kn_fop == &user_filtops) 1267 filt_usertouch(kn, kevp, EVENT_PROCESS); 1268 else 1269 *kevp = kn->kn_kevent; 1270 ++kevp; 1271 ++total; 1272 --count; 1273 1274 if (kn->kn_flags & EV_ONESHOT) { 1275 kn->kn_status &= ~KN_QUEUED; 1276 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1277 } else { 1278 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1279 if (kn->kn_flags & EV_CLEAR) { 1280 kn->kn_data = 0; 1281 kn->kn_fflags = 0; 1282 } 1283 if (kn->kn_flags & EV_DISPATCH) { 1284 kn->kn_status |= KN_DISABLED; 1285 } 1286 kn->kn_status &= ~(KN_QUEUED | 1287 KN_ACTIVE); 1288 } else { 1289 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); 1290 kq->kq_count++; 1291 } 1292 } 1293 } 1294 1295 /* 1296 * Handle any post-processing states 1297 */ 1298 knote_release(kn); 1299 } 1300 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); 1301 1302 lwkt_relpooltoken(kq); 1303 return (total); 1304 } 1305 1306 /* 1307 * XXX 1308 * This could be expanded to call kqueue_scan, if desired. 1309 * 1310 * MPSAFE 1311 */ 1312 static int 1313 kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags) 1314 { 1315 return (ENXIO); 1316 } 1317 1318 /* 1319 * MPSAFE 1320 */ 1321 static int 1322 kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags) 1323 { 1324 return (ENXIO); 1325 } 1326 1327 /* 1328 * MPALMOSTSAFE 1329 */ 1330 static int 1331 kqueue_ioctl(struct file *fp, u_long com, caddr_t data, 1332 struct ucred *cred, struct sysmsg *msg) 1333 { 1334 struct lwkt_token *tok; 1335 struct kqueue *kq; 1336 int error; 1337 1338 kq = (struct kqueue *)fp->f_data; 1339 tok = lwkt_token_pool_lookup(kq); 1340 lwkt_gettoken(tok); 1341 1342 switch(com) { 1343 case FIOASYNC: 1344 if (*(int *)data) 1345 kq->kq_state |= KQ_ASYNC; 1346 else 1347 kq->kq_state &= ~KQ_ASYNC; 1348 error = 0; 1349 break; 1350 case FIOSETOWN: 1351 error = fsetown(*(int *)data, &kq->kq_sigio); 1352 break; 1353 default: 1354 error = ENOTTY; 1355 break; 1356 } 1357 lwkt_reltoken(tok); 1358 return (error); 1359 } 1360 1361 /* 1362 * MPSAFE 1363 */ 1364 static int 1365 kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred) 1366 { 1367 struct kqueue *kq = (struct kqueue *)fp->f_data; 1368 1369 bzero((void *)st, sizeof(*st)); 1370 st->st_size = kq->kq_count; 1371 st->st_blksize = sizeof(struct kevent); 1372 st->st_mode = S_IFIFO; 1373 return (0); 1374 } 1375 1376 /* 1377 * MPSAFE 1378 */ 1379 static int 1380 kqueue_close(struct file *fp) 1381 { 1382 struct kqueue *kq = (struct kqueue *)fp->f_data; 1383 1384 kqueue_terminate(kq); 1385 1386 fp->f_data = NULL; 1387 funsetown(&kq->kq_sigio); 1388 1389 kfree(kq, M_KQUEUE); 1390 return (0); 1391 } 1392 1393 static void 1394 kqueue_wakeup(struct kqueue *kq) 1395 { 1396 if (kq->kq_state & KQ_SLEEP) { 1397 kq->kq_state &= ~KQ_SLEEP; 1398 wakeup(kq); 1399 } 1400 KNOTE(&kq->kq_kqinfo.ki_note, 0); 1401 } 1402 1403 /* 1404 * Calls filterops f_attach function, acquiring mplock if filter is not 1405 * marked as FILTEROP_MPSAFE. 1406 * 1407 * Caller must be holding the related kq token 1408 */ 1409 static int 1410 filter_attach(struct knote *kn) 1411 { 1412 int ret; 1413 1414 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { 1415 ret = kn->kn_fop->f_attach(kn); 1416 } else { 1417 get_mplock(); 1418 ret = kn->kn_fop->f_attach(kn); 1419 rel_mplock(); 1420 } 1421 return (ret); 1422 } 1423 1424 /* 1425 * Detach the knote and drop it, destroying the knote. 1426 * 1427 * Calls filterops f_detach function, acquiring mplock if filter is not 1428 * marked as FILTEROP_MPSAFE. 1429 * 1430 * Caller must be holding the related kq token 1431 */ 1432 static void 1433 knote_detach_and_drop(struct knote *kn) 1434 { 1435 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1436 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { 1437 kn->kn_fop->f_detach(kn); 1438 } else { 1439 get_mplock(); 1440 kn->kn_fop->f_detach(kn); 1441 rel_mplock(); 1442 } 1443 knote_drop(kn); 1444 } 1445 1446 /* 1447 * Calls filterops f_event function, acquiring mplock if filter is not 1448 * marked as FILTEROP_MPSAFE. 1449 * 1450 * If the knote is in the middle of being created or deleted we cannot 1451 * safely call the filter op. 1452 * 1453 * Caller must be holding the related kq token 1454 */ 1455 static int 1456 filter_event(struct knote *kn, long hint) 1457 { 1458 int ret; 1459 1460 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { 1461 ret = kn->kn_fop->f_event(kn, hint); 1462 } else { 1463 get_mplock(); 1464 ret = kn->kn_fop->f_event(kn, hint); 1465 rel_mplock(); 1466 } 1467 return (ret); 1468 } 1469 1470 /* 1471 * Walk down a list of knotes, activating them if their event has triggered. 1472 * 1473 * If we encounter any knotes which are undergoing processing we just mark 1474 * them for reprocessing and do not try to [re]activate the knote. However, 1475 * if a hint is being passed we have to wait and that makes things a bit 1476 * sticky. 1477 */ 1478 void 1479 knote(struct klist *list, long hint) 1480 { 1481 struct kqueue *kq; 1482 struct knote *kn; 1483 struct knote *kntmp; 1484 1485 lwkt_getpooltoken(list); 1486 restart: 1487 SLIST_FOREACH(kn, list, kn_next) { 1488 kq = kn->kn_kq; 1489 lwkt_getpooltoken(kq); 1490 1491 /* temporary verification hack */ 1492 SLIST_FOREACH(kntmp, list, kn_next) { 1493 if (kn == kntmp) 1494 break; 1495 } 1496 if (kn != kntmp || kn->kn_kq != kq) { 1497 lwkt_relpooltoken(kq); 1498 goto restart; 1499 } 1500 1501 if (kn->kn_status & KN_PROCESSING) { 1502 /* 1503 * Someone else is processing the knote, ask the 1504 * other thread to reprocess it and don't mess 1505 * with it otherwise. 1506 */ 1507 if (hint == 0) { 1508 kn->kn_status |= KN_REPROCESS; 1509 lwkt_relpooltoken(kq); 1510 continue; 1511 } 1512 1513 /* 1514 * If the hint is non-zero we have to wait or risk 1515 * losing the state the caller is trying to update. 1516 * 1517 * XXX This is a real problem, certain process 1518 * and signal filters will bump kn_data for 1519 * already-processed notes more than once if 1520 * we restart the list scan. FIXME. 1521 */ 1522 kn->kn_status |= KN_WAITING | KN_REPROCESS; 1523 tsleep(kn, 0, "knotec", hz); 1524 lwkt_relpooltoken(kq); 1525 goto restart; 1526 } 1527 1528 /* 1529 * Become the reprocessing master ourselves. 1530 * 1531 * If hint is non-zero running the event is mandatory 1532 * when not deleting so do it whether reprocessing is 1533 * set or not. 1534 */ 1535 kn->kn_status |= KN_PROCESSING; 1536 if ((kn->kn_status & KN_DELETING) == 0) { 1537 if (filter_event(kn, hint)) 1538 KNOTE_ACTIVATE(kn); 1539 } 1540 if (knote_release(kn)) { 1541 lwkt_relpooltoken(kq); 1542 goto restart; 1543 } 1544 lwkt_relpooltoken(kq); 1545 } 1546 lwkt_relpooltoken(list); 1547 } 1548 1549 /* 1550 * Insert knote at head of klist. 1551 * 1552 * This function may only be called via a filter function and thus 1553 * kq_token should already be held and marked for processing. 1554 */ 1555 void 1556 knote_insert(struct klist *klist, struct knote *kn) 1557 { 1558 lwkt_getpooltoken(klist); 1559 KKASSERT(kn->kn_status & KN_PROCESSING); 1560 SLIST_INSERT_HEAD(klist, kn, kn_next); 1561 lwkt_relpooltoken(klist); 1562 } 1563 1564 /* 1565 * Remove knote from a klist 1566 * 1567 * This function may only be called via a filter function and thus 1568 * kq_token should already be held and marked for processing. 1569 */ 1570 void 1571 knote_remove(struct klist *klist, struct knote *kn) 1572 { 1573 lwkt_getpooltoken(klist); 1574 KKASSERT(kn->kn_status & KN_PROCESSING); 1575 SLIST_REMOVE(klist, kn, knote, kn_next); 1576 lwkt_relpooltoken(klist); 1577 } 1578 1579 #if 0 1580 /* 1581 * Remove all knotes from a specified klist 1582 * 1583 * Only called from aio. 1584 */ 1585 void 1586 knote_empty(struct klist *list) 1587 { 1588 struct knote *kn; 1589 1590 lwkt_gettoken(&kq_token); 1591 while ((kn = SLIST_FIRST(list)) != NULL) { 1592 if (knote_acquire(kn)) 1593 knote_detach_and_drop(kn); 1594 } 1595 lwkt_reltoken(&kq_token); 1596 } 1597 #endif 1598 1599 void 1600 knote_assume_knotes(struct kqinfo *src, struct kqinfo *dst, 1601 struct filterops *ops, void *hook) 1602 { 1603 struct kqueue *kq; 1604 struct knote *kn; 1605 1606 lwkt_getpooltoken(&src->ki_note); 1607 lwkt_getpooltoken(&dst->ki_note); 1608 while ((kn = SLIST_FIRST(&src->ki_note)) != NULL) { 1609 kq = kn->kn_kq; 1610 lwkt_getpooltoken(kq); 1611 if (SLIST_FIRST(&src->ki_note) != kn || kn->kn_kq != kq) { 1612 lwkt_relpooltoken(kq); 1613 continue; 1614 } 1615 if (knote_acquire(kn)) { 1616 knote_remove(&src->ki_note, kn); 1617 kn->kn_fop = ops; 1618 kn->kn_hook = hook; 1619 knote_insert(&dst->ki_note, kn); 1620 knote_release(kn); 1621 /* kn may be invalid now */ 1622 } 1623 lwkt_relpooltoken(kq); 1624 } 1625 lwkt_relpooltoken(&dst->ki_note); 1626 lwkt_relpooltoken(&src->ki_note); 1627 } 1628 1629 /* 1630 * Remove all knotes referencing a specified fd 1631 */ 1632 void 1633 knote_fdclose(struct file *fp, struct filedesc *fdp, int fd) 1634 { 1635 struct kqueue *kq; 1636 struct knote *kn; 1637 struct knote *kntmp; 1638 1639 lwkt_getpooltoken(&fp->f_klist); 1640 restart: 1641 SLIST_FOREACH(kn, &fp->f_klist, kn_link) { 1642 if (kn->kn_kq->kq_fdp == fdp && kn->kn_id == fd) { 1643 kq = kn->kn_kq; 1644 lwkt_getpooltoken(kq); 1645 1646 /* temporary verification hack */ 1647 SLIST_FOREACH(kntmp, &fp->f_klist, kn_link) { 1648 if (kn == kntmp) 1649 break; 1650 } 1651 if (kn != kntmp || kn->kn_kq->kq_fdp != fdp || 1652 kn->kn_id != fd || kn->kn_kq != kq) { 1653 lwkt_relpooltoken(kq); 1654 goto restart; 1655 } 1656 if (knote_acquire(kn)) 1657 knote_detach_and_drop(kn); 1658 lwkt_relpooltoken(kq); 1659 goto restart; 1660 } 1661 } 1662 lwkt_relpooltoken(&fp->f_klist); 1663 } 1664 1665 /* 1666 * Low level attach function. 1667 * 1668 * The knote should already be marked for processing. 1669 * Caller must hold the related kq token. 1670 */ 1671 static void 1672 knote_attach(struct knote *kn) 1673 { 1674 struct klist *list; 1675 struct kqueue *kq = kn->kn_kq; 1676 1677 if (kn->kn_fop->f_flags & FILTEROP_ISFD) { 1678 KKASSERT(kn->kn_fp); 1679 list = &kn->kn_fp->f_klist; 1680 } else { 1681 if (kq->kq_knhashmask == 0) 1682 kq->kq_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1683 &kq->kq_knhashmask); 1684 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1685 } 1686 lwkt_getpooltoken(list); 1687 SLIST_INSERT_HEAD(list, kn, kn_link); 1688 TAILQ_INSERT_HEAD(&kq->kq_knlist, kn, kn_kqlink); 1689 lwkt_relpooltoken(list); 1690 } 1691 1692 /* 1693 * Low level drop function. 1694 * 1695 * The knote should already be marked for processing. 1696 * Caller must hold the related kq token. 1697 */ 1698 static void 1699 knote_drop(struct knote *kn) 1700 { 1701 struct kqueue *kq; 1702 struct klist *list; 1703 1704 kq = kn->kn_kq; 1705 1706 if (kn->kn_fop->f_flags & FILTEROP_ISFD) 1707 list = &kn->kn_fp->f_klist; 1708 else 1709 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1710 1711 lwkt_getpooltoken(list); 1712 SLIST_REMOVE(list, kn, knote, kn_link); 1713 TAILQ_REMOVE(&kq->kq_knlist, kn, kn_kqlink); 1714 if (kn->kn_status & KN_QUEUED) 1715 knote_dequeue(kn); 1716 if (kn->kn_fop->f_flags & FILTEROP_ISFD) { 1717 fdrop(kn->kn_fp); 1718 kn->kn_fp = NULL; 1719 } 1720 knote_free(kn); 1721 lwkt_relpooltoken(list); 1722 } 1723 1724 /* 1725 * Low level enqueue function. 1726 * 1727 * The knote should already be marked for processing. 1728 * Caller must be holding the kq token 1729 */ 1730 static void 1731 knote_enqueue(struct knote *kn) 1732 { 1733 struct kqueue *kq = kn->kn_kq; 1734 1735 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 1736 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); 1737 kn->kn_status |= KN_QUEUED; 1738 ++kq->kq_count; 1739 1740 /* 1741 * Send SIGIO on request (typically set up as a mailbox signal) 1742 */ 1743 if (kq->kq_sigio && (kq->kq_state & KQ_ASYNC) && kq->kq_count == 1) 1744 pgsigio(kq->kq_sigio, SIGIO, 0); 1745 1746 kqueue_wakeup(kq); 1747 } 1748 1749 /* 1750 * Low level dequeue function. 1751 * 1752 * The knote should already be marked for processing. 1753 * Caller must be holding the kq token 1754 */ 1755 static void 1756 knote_dequeue(struct knote *kn) 1757 { 1758 struct kqueue *kq = kn->kn_kq; 1759 1760 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 1761 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); 1762 kn->kn_status &= ~KN_QUEUED; 1763 kq->kq_count--; 1764 } 1765 1766 static struct knote * 1767 knote_alloc(void) 1768 { 1769 return kmalloc(sizeof(struct knote), M_KQUEUE, M_WAITOK); 1770 } 1771 1772 static void 1773 knote_free(struct knote *kn) 1774 { 1775 kfree(kn, M_KQUEUE); 1776 } 1777