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 * $DragonFly: src/sys/kern/kern_event.c,v 1.33 2007/02/03 17:05:57 corecode Exp $ 28 */ 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/kernel.h> 33 #include <sys/proc.h> 34 #include <sys/malloc.h> 35 #include <sys/unistd.h> 36 #include <sys/file.h> 37 #include <sys/lock.h> 38 #include <sys/fcntl.h> 39 #include <sys/queue.h> 40 #include <sys/event.h> 41 #include <sys/eventvar.h> 42 #include <sys/protosw.h> 43 #include <sys/socket.h> 44 #include <sys/socketvar.h> 45 #include <sys/stat.h> 46 #include <sys/sysctl.h> 47 #include <sys/sysproto.h> 48 #include <sys/thread.h> 49 #include <sys/uio.h> 50 #include <sys/signalvar.h> 51 #include <sys/filio.h> 52 #include <sys/ktr.h> 53 54 #include <sys/thread2.h> 55 #include <sys/file2.h> 56 #include <sys/mplock2.h> 57 58 #include <vm/vm_zone.h> 59 60 /* 61 * Global token for kqueue subsystem 62 */ 63 struct lwkt_token kq_token = LWKT_TOKEN_UP_INITIALIZER(kq_token); 64 65 MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 66 67 struct kevent_copyin_args { 68 struct kevent_args *ka; 69 int pchanges; 70 }; 71 72 static int kqueue_sleep(struct kqueue *kq, struct timespec *tsp); 73 static int kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, 74 struct knote *marker); 75 static int kqueue_read(struct file *fp, struct uio *uio, 76 struct ucred *cred, int flags); 77 static int kqueue_write(struct file *fp, struct uio *uio, 78 struct ucred *cred, int flags); 79 static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data, 80 struct ucred *cred, struct sysmsg *msg); 81 static int kqueue_kqfilter(struct file *fp, struct knote *kn); 82 static int kqueue_stat(struct file *fp, struct stat *st, 83 struct ucred *cred); 84 static int kqueue_close(struct file *fp); 85 static void kqueue_wakeup(struct kqueue *kq); 86 static int filter_attach(struct knote *kn); 87 static int filter_event(struct knote *kn, long hint); 88 89 /* 90 * MPSAFE 91 */ 92 static struct fileops kqueueops = { 93 .fo_read = kqueue_read, 94 .fo_write = kqueue_write, 95 .fo_ioctl = kqueue_ioctl, 96 .fo_kqfilter = kqueue_kqfilter, 97 .fo_stat = kqueue_stat, 98 .fo_close = kqueue_close, 99 .fo_shutdown = nofo_shutdown 100 }; 101 102 static void knote_attach(struct knote *kn); 103 static void knote_drop(struct knote *kn); 104 static void knote_detach_and_drop(struct knote *kn); 105 static void knote_enqueue(struct knote *kn); 106 static void knote_dequeue(struct knote *kn); 107 static void knote_init(void); 108 static struct knote *knote_alloc(void); 109 static void knote_free(struct knote *kn); 110 111 static void filt_kqdetach(struct knote *kn); 112 static int filt_kqueue(struct knote *kn, long hint); 113 static int filt_procattach(struct knote *kn); 114 static void filt_procdetach(struct knote *kn); 115 static int filt_proc(struct knote *kn, long hint); 116 static int filt_fileattach(struct knote *kn); 117 static void filt_timerexpire(void *knx); 118 static int filt_timerattach(struct knote *kn); 119 static void filt_timerdetach(struct knote *kn); 120 static int filt_timer(struct knote *kn, long hint); 121 122 static struct filterops file_filtops = 123 { FILTEROP_ISFD, filt_fileattach, NULL, NULL }; 124 static struct filterops kqread_filtops = 125 { FILTEROP_ISFD, NULL, filt_kqdetach, filt_kqueue }; 126 static struct filterops proc_filtops = 127 { 0, filt_procattach, filt_procdetach, filt_proc }; 128 static struct filterops timer_filtops = 129 { 0, filt_timerattach, filt_timerdetach, filt_timer }; 130 131 static vm_zone_t knote_zone; 132 static int kq_ncallouts = 0; 133 static int kq_calloutmax = (4 * 1024); 134 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 135 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 136 static int kq_checkloop = 1000000; 137 SYSCTL_INT(_kern, OID_AUTO, kq_checkloop, CTLFLAG_RW, 138 &kq_checkloop, 0, "Maximum number of callouts allocated for kqueue"); 139 140 #define KNOTE_ACTIVATE(kn) do { \ 141 kn->kn_status |= KN_ACTIVE; \ 142 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 143 knote_enqueue(kn); \ 144 } while(0) 145 146 #define KN_HASHSIZE 64 /* XXX should be tunable */ 147 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 148 149 extern struct filterops aio_filtops; 150 extern struct filterops sig_filtops; 151 152 /* 153 * Table for for all system-defined filters. 154 */ 155 static struct filterops *sysfilt_ops[] = { 156 &file_filtops, /* EVFILT_READ */ 157 &file_filtops, /* EVFILT_WRITE */ 158 &aio_filtops, /* EVFILT_AIO */ 159 &file_filtops, /* EVFILT_VNODE */ 160 &proc_filtops, /* EVFILT_PROC */ 161 &sig_filtops, /* EVFILT_SIGNAL */ 162 &timer_filtops, /* EVFILT_TIMER */ 163 &file_filtops, /* EVFILT_EXCEPT */ 164 }; 165 166 static int 167 filt_fileattach(struct knote *kn) 168 { 169 return (fo_kqfilter(kn->kn_fp, kn)); 170 } 171 172 /* 173 * MPSAFE 174 */ 175 static int 176 kqueue_kqfilter(struct file *fp, struct knote *kn) 177 { 178 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 179 180 if (kn->kn_filter != EVFILT_READ) 181 return (EOPNOTSUPP); 182 183 kn->kn_fop = &kqread_filtops; 184 knote_insert(&kq->kq_kqinfo.ki_note, kn); 185 return (0); 186 } 187 188 static void 189 filt_kqdetach(struct knote *kn) 190 { 191 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 192 193 knote_remove(&kq->kq_kqinfo.ki_note, kn); 194 } 195 196 /*ARGSUSED*/ 197 static int 198 filt_kqueue(struct knote *kn, long hint) 199 { 200 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 201 202 kn->kn_data = kq->kq_count; 203 return (kn->kn_data > 0); 204 } 205 206 static int 207 filt_procattach(struct knote *kn) 208 { 209 struct proc *p; 210 int immediate; 211 212 immediate = 0; 213 lwkt_gettoken(&proc_token); 214 p = pfind(kn->kn_id); 215 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 216 p = zpfind(kn->kn_id); 217 immediate = 1; 218 } 219 if (p == NULL) { 220 lwkt_reltoken(&proc_token); 221 return (ESRCH); 222 } 223 if (!PRISON_CHECK(curthread->td_ucred, p->p_ucred)) { 224 lwkt_reltoken(&proc_token); 225 return (EACCES); 226 } 227 228 kn->kn_ptr.p_proc = p; 229 kn->kn_flags |= EV_CLEAR; /* automatically set */ 230 231 /* 232 * internal flag indicating registration done by kernel 233 */ 234 if (kn->kn_flags & EV_FLAG1) { 235 kn->kn_data = kn->kn_sdata; /* ppid */ 236 kn->kn_fflags = NOTE_CHILD; 237 kn->kn_flags &= ~EV_FLAG1; 238 } 239 240 knote_insert(&p->p_klist, kn); 241 242 /* 243 * Immediately activate any exit notes if the target process is a 244 * zombie. This is necessary to handle the case where the target 245 * process, e.g. a child, dies before the kevent is negistered. 246 */ 247 if (immediate && filt_proc(kn, NOTE_EXIT)) 248 KNOTE_ACTIVATE(kn); 249 lwkt_reltoken(&proc_token); 250 251 return (0); 252 } 253 254 /* 255 * The knote may be attached to a different process, which may exit, 256 * leaving nothing for the knote to be attached to. So when the process 257 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 258 * it will be deleted when read out. However, as part of the knote deletion, 259 * this routine is called, so a check is needed to avoid actually performing 260 * a detach, because the original process does not exist any more. 261 */ 262 static void 263 filt_procdetach(struct knote *kn) 264 { 265 struct proc *p; 266 267 if (kn->kn_status & KN_DETACHED) 268 return; 269 /* XXX locking? take proc_token here? */ 270 p = kn->kn_ptr.p_proc; 271 knote_remove(&p->p_klist, kn); 272 } 273 274 static int 275 filt_proc(struct knote *kn, long hint) 276 { 277 u_int event; 278 279 /* 280 * mask off extra data 281 */ 282 event = (u_int)hint & NOTE_PCTRLMASK; 283 284 /* 285 * if the user is interested in this event, record it. 286 */ 287 if (kn->kn_sfflags & event) 288 kn->kn_fflags |= event; 289 290 /* 291 * Process is gone, so flag the event as finished. Detach the 292 * knote from the process now because the process will be poof, 293 * gone later on. 294 */ 295 if (event == NOTE_EXIT) { 296 struct proc *p = kn->kn_ptr.p_proc; 297 if ((kn->kn_status & KN_DETACHED) == 0) { 298 knote_remove(&p->p_klist, kn); 299 kn->kn_status |= KN_DETACHED; 300 kn->kn_data = p->p_xstat; 301 kn->kn_ptr.p_proc = NULL; 302 } 303 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 304 return (1); 305 } 306 307 /* 308 * process forked, and user wants to track the new process, 309 * so attach a new knote to it, and immediately report an 310 * event with the parent's pid. 311 */ 312 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) { 313 struct kevent kev; 314 int error; 315 316 /* 317 * register knote with new process. 318 */ 319 kev.ident = hint & NOTE_PDATAMASK; /* pid */ 320 kev.filter = kn->kn_filter; 321 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 322 kev.fflags = kn->kn_sfflags; 323 kev.data = kn->kn_id; /* parent */ 324 kev.udata = kn->kn_kevent.udata; /* preserve udata */ 325 error = kqueue_register(kn->kn_kq, &kev); 326 if (error) 327 kn->kn_fflags |= NOTE_TRACKERR; 328 } 329 330 return (kn->kn_fflags != 0); 331 } 332 333 static void 334 filt_timerexpire(void *knx) 335 { 336 struct knote *kn = knx; 337 struct callout *calloutp; 338 struct timeval tv; 339 int tticks; 340 341 lwkt_gettoken(&kq_token); 342 343 kn->kn_data++; 344 KNOTE_ACTIVATE(kn); 345 346 if ((kn->kn_flags & EV_ONESHOT) == 0) { 347 tv.tv_sec = kn->kn_sdata / 1000; 348 tv.tv_usec = (kn->kn_sdata % 1000) * 1000; 349 tticks = tvtohz_high(&tv); 350 calloutp = (struct callout *)kn->kn_hook; 351 callout_reset(calloutp, tticks, filt_timerexpire, kn); 352 } 353 354 lwkt_reltoken(&kq_token); 355 } 356 357 /* 358 * data contains amount of time to sleep, in milliseconds 359 */ 360 static int 361 filt_timerattach(struct knote *kn) 362 { 363 struct callout *calloutp; 364 struct timeval tv; 365 int tticks; 366 367 if (kq_ncallouts >= kq_calloutmax) 368 return (ENOMEM); 369 kq_ncallouts++; 370 371 tv.tv_sec = kn->kn_sdata / 1000; 372 tv.tv_usec = (kn->kn_sdata % 1000) * 1000; 373 tticks = tvtohz_high(&tv); 374 375 kn->kn_flags |= EV_CLEAR; /* automatically set */ 376 MALLOC(calloutp, struct callout *, sizeof(*calloutp), 377 M_KQUEUE, M_WAITOK); 378 callout_init(calloutp); 379 kn->kn_hook = (caddr_t)calloutp; 380 callout_reset(calloutp, tticks, filt_timerexpire, kn); 381 382 return (0); 383 } 384 385 static void 386 filt_timerdetach(struct knote *kn) 387 { 388 struct callout *calloutp; 389 390 calloutp = (struct callout *)kn->kn_hook; 391 callout_stop(calloutp); 392 FREE(calloutp, M_KQUEUE); 393 kq_ncallouts--; 394 } 395 396 static int 397 filt_timer(struct knote *kn, long hint) 398 { 399 400 return (kn->kn_data != 0); 401 } 402 403 /* 404 * Initialize a kqueue. 405 * 406 * NOTE: The lwp/proc code initializes a kqueue for select/poll ops. 407 * 408 * MPSAFE 409 */ 410 void 411 kqueue_init(struct kqueue *kq, struct filedesc *fdp) 412 { 413 TAILQ_INIT(&kq->kq_knpend); 414 TAILQ_INIT(&kq->kq_knlist); 415 kq->kq_count = 0; 416 kq->kq_fdp = fdp; 417 SLIST_INIT(&kq->kq_kqinfo.ki_note); 418 } 419 420 /* 421 * Terminate a kqueue. Freeing the actual kq itself is left up to the 422 * caller (it might be embedded in a lwp so we don't do it here). 423 */ 424 void 425 kqueue_terminate(struct kqueue *kq) 426 { 427 struct knote *kn; 428 429 lwkt_gettoken(&kq_token); 430 while ((kn = TAILQ_FIRST(&kq->kq_knlist)) != NULL) 431 knote_detach_and_drop(kn); 432 433 if (kq->kq_knhash) { 434 kfree(kq->kq_knhash, M_KQUEUE); 435 kq->kq_knhash = NULL; 436 kq->kq_knhashmask = 0; 437 } 438 lwkt_reltoken(&kq_token); 439 } 440 441 /* 442 * MPSAFE 443 */ 444 int 445 sys_kqueue(struct kqueue_args *uap) 446 { 447 struct thread *td = curthread; 448 struct kqueue *kq; 449 struct file *fp; 450 int fd, error; 451 452 error = falloc(td->td_lwp, &fp, &fd); 453 if (error) 454 return (error); 455 fp->f_flag = FREAD | FWRITE; 456 fp->f_type = DTYPE_KQUEUE; 457 fp->f_ops = &kqueueops; 458 459 kq = kmalloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO); 460 kqueue_init(kq, td->td_proc->p_fd); 461 fp->f_data = kq; 462 463 fsetfd(kq->kq_fdp, fp, fd); 464 uap->sysmsg_result = fd; 465 fdrop(fp); 466 return (error); 467 } 468 469 /* 470 * Copy 'count' items into the destination list pointed to by uap->eventlist. 471 */ 472 static int 473 kevent_copyout(void *arg, struct kevent *kevp, int count, int *res) 474 { 475 struct kevent_copyin_args *kap; 476 int error; 477 478 kap = (struct kevent_copyin_args *)arg; 479 480 error = copyout(kevp, kap->ka->eventlist, count * sizeof(*kevp)); 481 if (error == 0) { 482 kap->ka->eventlist += count; 483 *res += count; 484 } else { 485 *res = -1; 486 } 487 488 return (error); 489 } 490 491 /* 492 * Copy at most 'max' items from the list pointed to by kap->changelist, 493 * return number of items in 'events'. 494 */ 495 static int 496 kevent_copyin(void *arg, struct kevent *kevp, int max, int *events) 497 { 498 struct kevent_copyin_args *kap; 499 int error, count; 500 501 kap = (struct kevent_copyin_args *)arg; 502 503 count = min(kap->ka->nchanges - kap->pchanges, max); 504 error = copyin(kap->ka->changelist, kevp, count * sizeof *kevp); 505 if (error == 0) { 506 kap->ka->changelist += count; 507 kap->pchanges += count; 508 *events = count; 509 } 510 511 return (error); 512 } 513 514 /* 515 * MPSAFE 516 */ 517 int 518 kern_kevent(struct kqueue *kq, int nevents, int *res, void *uap, 519 k_copyin_fn kevent_copyinfn, k_copyout_fn kevent_copyoutfn, 520 struct timespec *tsp_in) 521 { 522 struct kevent *kevp; 523 struct timespec *tsp; 524 int i, n, total, error, nerrors = 0; 525 int lres; 526 int limit = kq_checkloop; 527 struct kevent kev[KQ_NEVENTS]; 528 struct knote marker; 529 530 tsp = tsp_in; 531 *res = 0; 532 533 lwkt_gettoken(&kq_token); 534 for ( ;; ) { 535 n = 0; 536 error = kevent_copyinfn(uap, kev, KQ_NEVENTS, &n); 537 if (error) 538 goto done; 539 if (n == 0) 540 break; 541 for (i = 0; i < n; i++) { 542 kevp = &kev[i]; 543 kevp->flags &= ~EV_SYSFLAGS; 544 error = kqueue_register(kq, kevp); 545 546 /* 547 * If a registration returns an error we 548 * immediately post the error. The kevent() 549 * call itself will fail with the error if 550 * no space is available for posting. 551 * 552 * Such errors normally bypass the timeout/blocking 553 * code. However, if the copyoutfn function refuses 554 * to post the error (see sys_poll()), then we 555 * ignore it too. 556 */ 557 if (error) { 558 kevp->flags = EV_ERROR; 559 kevp->data = error; 560 lres = *res; 561 kevent_copyoutfn(uap, kevp, 1, res); 562 if (lres != *res) { 563 nevents--; 564 nerrors++; 565 } 566 } 567 } 568 } 569 if (nerrors) { 570 error = 0; 571 goto done; 572 } 573 574 /* 575 * Acquire/wait for events - setup timeout 576 */ 577 if (tsp != NULL) { 578 struct timespec ats; 579 580 if (tsp->tv_sec || tsp->tv_nsec) { 581 nanouptime(&ats); 582 timespecadd(tsp, &ats); /* tsp = target time */ 583 } 584 } 585 586 /* 587 * Loop as required. 588 * 589 * Collect as many events as we can. Sleeping on successive 590 * loops is disabled if copyoutfn has incremented (*res). 591 * 592 * The loop stops if an error occurs, all events have been 593 * scanned (the marker has been reached), or fewer than the 594 * maximum number of events is found. 595 * 596 * The copyoutfn function does not have to increment (*res) in 597 * order for the loop to continue. 598 * 599 * NOTE: doselect() usually passes 0x7FFFFFFF for nevents. 600 */ 601 total = 0; 602 error = 0; 603 marker.kn_filter = EVFILT_MARKER; 604 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); 605 while ((n = nevents - total) > 0) { 606 if (n > KQ_NEVENTS) 607 n = KQ_NEVENTS; 608 609 /* 610 * If no events are pending sleep until timeout (if any) 611 * or an event occurs. 612 * 613 * After the sleep completes the marker is moved to the 614 * end of the list, making any received events available 615 * to our scan. 616 */ 617 if (kq->kq_count == 0 && *res == 0) { 618 error = kqueue_sleep(kq, tsp); 619 if (error) 620 break; 621 622 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); 623 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); 624 } 625 626 /* 627 * Process all received events 628 * Account for all non-spurious events in our total 629 */ 630 i = kqueue_scan(kq, kev, n, &marker); 631 if (i) { 632 lres = *res; 633 error = kevent_copyoutfn(uap, kev, i, res); 634 total += *res - lres; 635 if (error) 636 break; 637 } 638 if (limit && --limit == 0) 639 panic("kqueue: checkloop failed i=%d", i); 640 641 /* 642 * Normally when fewer events are returned than requested 643 * we can stop. However, if only spurious events were 644 * collected the copyout will not bump (*res) and we have 645 * to continue. 646 */ 647 if (i < n && *res) 648 break; 649 650 /* 651 * Deal with an edge case where spurious events can cause 652 * a loop to occur without moving the marker. This can 653 * prevent kqueue_scan() from picking up new events which 654 * race us. We must be sure to move the marker for this 655 * case. 656 * 657 * NOTE: We do not want to move the marker if events 658 * were scanned because normal kqueue operations 659 * may reactivate events. Moving the marker in 660 * that case could result in duplicates for the 661 * same event. 662 */ 663 if (i == 0) { 664 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); 665 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); 666 } 667 } 668 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); 669 670 /* Timeouts do not return EWOULDBLOCK. */ 671 if (error == EWOULDBLOCK) 672 error = 0; 673 674 done: 675 lwkt_reltoken(&kq_token); 676 return (error); 677 } 678 679 /* 680 * MPALMOSTSAFE 681 */ 682 int 683 sys_kevent(struct kevent_args *uap) 684 { 685 struct thread *td = curthread; 686 struct proc *p = td->td_proc; 687 struct timespec ts, *tsp; 688 struct kqueue *kq; 689 struct file *fp = NULL; 690 struct kevent_copyin_args *kap, ka; 691 int error; 692 693 if (uap->timeout) { 694 error = copyin(uap->timeout, &ts, sizeof(ts)); 695 if (error) 696 return (error); 697 tsp = &ts; 698 } else { 699 tsp = NULL; 700 } 701 702 fp = holdfp(p->p_fd, uap->fd, -1); 703 if (fp == NULL) 704 return (EBADF); 705 if (fp->f_type != DTYPE_KQUEUE) { 706 fdrop(fp); 707 return (EBADF); 708 } 709 710 kq = (struct kqueue *)fp->f_data; 711 712 kap = &ka; 713 kap->ka = uap; 714 kap->pchanges = 0; 715 716 error = kern_kevent(kq, uap->nevents, &uap->sysmsg_result, kap, 717 kevent_copyin, kevent_copyout, tsp); 718 719 fdrop(fp); 720 721 return (error); 722 } 723 724 int 725 kqueue_register(struct kqueue *kq, struct kevent *kev) 726 { 727 struct filedesc *fdp = kq->kq_fdp; 728 struct filterops *fops; 729 struct file *fp = NULL; 730 struct knote *kn = NULL; 731 int error = 0; 732 733 if (kev->filter < 0) { 734 if (kev->filter + EVFILT_SYSCOUNT < 0) 735 return (EINVAL); 736 fops = sysfilt_ops[~kev->filter]; /* to 0-base index */ 737 } else { 738 /* 739 * XXX 740 * filter attach routine is responsible for insuring that 741 * the identifier can be attached to it. 742 */ 743 kprintf("unknown filter: %d\n", kev->filter); 744 return (EINVAL); 745 } 746 747 lwkt_gettoken(&kq_token); 748 if (fops->f_flags & FILTEROP_ISFD) { 749 /* validate descriptor */ 750 fp = holdfp(fdp, kev->ident, -1); 751 if (fp == NULL) { 752 lwkt_reltoken(&kq_token); 753 return (EBADF); 754 } 755 756 SLIST_FOREACH(kn, &fp->f_klist, kn_link) { 757 if (kn->kn_kq == kq && 758 kn->kn_filter == kev->filter && 759 kn->kn_id == kev->ident) { 760 break; 761 } 762 } 763 } else { 764 if (kq->kq_knhashmask) { 765 struct klist *list; 766 767 list = &kq->kq_knhash[ 768 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 769 SLIST_FOREACH(kn, list, kn_link) { 770 if (kn->kn_id == kev->ident && 771 kn->kn_filter == kev->filter) 772 break; 773 } 774 } 775 } 776 777 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) { 778 error = ENOENT; 779 goto done; 780 } 781 782 /* 783 * kn now contains the matching knote, or NULL if no match 784 */ 785 if (kev->flags & EV_ADD) { 786 if (kn == NULL) { 787 kn = knote_alloc(); 788 if (kn == NULL) { 789 error = ENOMEM; 790 goto done; 791 } 792 kn->kn_fp = fp; 793 kn->kn_kq = kq; 794 kn->kn_fop = fops; 795 796 /* 797 * apply reference count to knote structure, and 798 * do not release it at the end of this routine. 799 */ 800 fp = NULL; 801 802 kn->kn_sfflags = kev->fflags; 803 kn->kn_sdata = kev->data; 804 kev->fflags = 0; 805 kev->data = 0; 806 kn->kn_kevent = *kev; 807 808 /* 809 * Interlock against creation/deletion races due 810 * to f_attach() blocking. knote_attach() will set 811 * KN_CREATING. 812 */ 813 knote_attach(kn); 814 if ((error = filter_attach(kn)) != 0) { 815 kn->kn_status |= KN_DELETING; 816 knote_drop(kn); 817 goto done; 818 } 819 kn->kn_status &= ~KN_CREATING; 820 821 /* 822 * Interlock against close races which remove our 823 * knotes. We do not want to end up with a knote 824 * on a closed descriptor. 825 */ 826 if ((fops->f_flags & FILTEROP_ISFD) && 827 (error = checkfdclosed(fdp, kev->ident, kn->kn_fp)) != 0) { 828 knote_detach_and_drop(kn); 829 goto done; 830 } 831 } else { 832 /* 833 * The user may change some filter values after the 834 * initial EV_ADD, but doing so will not reset any 835 * filter which have already been triggered. 836 */ 837 kn->kn_sfflags = kev->fflags; 838 kn->kn_sdata = kev->data; 839 kn->kn_kevent.udata = kev->udata; 840 } 841 842 if (filter_event(kn, 0)) 843 KNOTE_ACTIVATE(kn); 844 } else if (kev->flags & EV_DELETE) { 845 knote_detach_and_drop(kn); 846 goto done; 847 } 848 849 if ((kev->flags & EV_DISABLE) && 850 ((kn->kn_status & KN_DISABLED) == 0)) { 851 kn->kn_status |= KN_DISABLED; 852 } 853 854 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 855 kn->kn_status &= ~KN_DISABLED; 856 if ((kn->kn_status & KN_ACTIVE) && 857 ((kn->kn_status & KN_QUEUED) == 0)) 858 knote_enqueue(kn); 859 } 860 861 done: 862 lwkt_reltoken(&kq_token); 863 if (fp != NULL) 864 fdrop(fp); 865 return (error); 866 } 867 868 /* 869 * Block as necessary until the target time is reached. 870 * If tsp is NULL we block indefinitely. If tsp->ts_secs/nsecs are both 871 * 0 we do not block at all. 872 */ 873 static int 874 kqueue_sleep(struct kqueue *kq, struct timespec *tsp) 875 { 876 int error = 0; 877 878 if (tsp == NULL) { 879 kq->kq_state |= KQ_SLEEP; 880 error = tsleep(kq, PCATCH, "kqread", 0); 881 } else if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) { 882 error = EWOULDBLOCK; 883 } else { 884 struct timespec ats; 885 struct timespec atx = *tsp; 886 int timeout; 887 888 nanouptime(&ats); 889 timespecsub(&atx, &ats); 890 if (ats.tv_sec < 0) { 891 error = EWOULDBLOCK; 892 } else { 893 timeout = atx.tv_sec > 24 * 60 * 60 ? 894 24 * 60 * 60 * hz : tstohz_high(&atx); 895 kq->kq_state |= KQ_SLEEP; 896 error = tsleep(kq, PCATCH, "kqread", timeout); 897 } 898 } 899 900 /* don't restart after signals... */ 901 if (error == ERESTART) 902 return (EINTR); 903 904 return (error); 905 } 906 907 /* 908 * Scan the kqueue, return the number of active events placed in kevp up 909 * to count. 910 * 911 * Continuous mode events may get recycled, do not continue scanning past 912 * marker unless no events have been collected. 913 */ 914 static int 915 kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, 916 struct knote *marker) 917 { 918 struct knote *kn, local_marker; 919 int total; 920 921 total = 0; 922 local_marker.kn_filter = EVFILT_MARKER; 923 924 /* 925 * Collect events. 926 */ 927 TAILQ_INSERT_HEAD(&kq->kq_knpend, &local_marker, kn_tqe); 928 while (count) { 929 kn = TAILQ_NEXT(&local_marker, kn_tqe); 930 if (kn->kn_filter == EVFILT_MARKER) { 931 /* Marker reached, we are done */ 932 if (kn == marker) 933 break; 934 935 /* Move local marker past some other threads marker */ 936 kn = TAILQ_NEXT(kn, kn_tqe); 937 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); 938 TAILQ_INSERT_BEFORE(kn, &local_marker, kn_tqe); 939 continue; 940 } 941 942 /* 943 * Remove the event for processing. 944 * 945 * WARNING! We must leave KN_QUEUED set to prevent the 946 * event from being KNOTE()d again while we 947 * potentially block in the filter function. 948 * 949 * This protects the knote from everything except 950 * getting dropped. 951 * 952 * WARNING! KN_PROCESSING is meant to handle any cases 953 * that leaving KN_QUEUED set does not. 954 */ 955 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); 956 kq->kq_count--; 957 kn->kn_status |= KN_PROCESSING; 958 959 /* 960 * Even though close/dup2 will clean out pending knotes this 961 * code is MPSAFE and it is possible to race a close inbetween 962 * the removal of its descriptor and the clearing out of the 963 * knote(s). 964 * 965 * In this case we must ensure that the knote is not queued 966 * to knpend or we risk an infinite kernel loop calling 967 * kscan, because the select/poll code will not be able to 968 * delete the event. 969 */ 970 if ((kn->kn_fop->f_flags & FILTEROP_ISFD) && 971 checkfdclosed(kq->kq_fdp, kn->kn_kevent.ident, kn->kn_fp)) { 972 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE | 973 KN_PROCESSING); 974 continue; 975 } 976 977 /* 978 * If disabled we ensure the event is not queued but leave 979 * its active bit set. On re-enablement the event may be 980 * immediately triggered. 981 */ 982 if (kn->kn_status & KN_DISABLED) { 983 kn->kn_status &= ~(KN_QUEUED | KN_PROCESSING); 984 continue; 985 } 986 987 /* 988 * If not running in one-shot mode and the event is no 989 * longer present we ensure it is removed from the queue and 990 * ignore it. 991 */ 992 if ((kn->kn_flags & EV_ONESHOT) == 0 && 993 filter_event(kn, 0) == 0) { 994 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE | 995 KN_PROCESSING); 996 continue; 997 } 998 999 *kevp++ = kn->kn_kevent; 1000 ++total; 1001 --count; 1002 1003 /* 1004 * Post-event action on the note 1005 */ 1006 if (kn->kn_flags & EV_ONESHOT) { 1007 kn->kn_status &= ~(KN_QUEUED | KN_PROCESSING); 1008 knote_detach_and_drop(kn); 1009 } else if (kn->kn_flags & EV_CLEAR) { 1010 kn->kn_data = 0; 1011 kn->kn_fflags = 0; 1012 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE | 1013 KN_PROCESSING); 1014 } else { 1015 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); 1016 kq->kq_count++; 1017 kn->kn_status &= ~KN_PROCESSING; 1018 } 1019 } 1020 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); 1021 1022 return (total); 1023 } 1024 1025 /* 1026 * XXX 1027 * This could be expanded to call kqueue_scan, if desired. 1028 * 1029 * MPSAFE 1030 */ 1031 static int 1032 kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags) 1033 { 1034 return (ENXIO); 1035 } 1036 1037 /* 1038 * MPSAFE 1039 */ 1040 static int 1041 kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags) 1042 { 1043 return (ENXIO); 1044 } 1045 1046 /* 1047 * MPALMOSTSAFE 1048 */ 1049 static int 1050 kqueue_ioctl(struct file *fp, u_long com, caddr_t data, 1051 struct ucred *cred, struct sysmsg *msg) 1052 { 1053 struct kqueue *kq; 1054 int error; 1055 1056 lwkt_gettoken(&kq_token); 1057 kq = (struct kqueue *)fp->f_data; 1058 1059 switch(com) { 1060 case FIOASYNC: 1061 if (*(int *)data) 1062 kq->kq_state |= KQ_ASYNC; 1063 else 1064 kq->kq_state &= ~KQ_ASYNC; 1065 error = 0; 1066 break; 1067 case FIOSETOWN: 1068 error = fsetown(*(int *)data, &kq->kq_sigio); 1069 break; 1070 default: 1071 error = ENOTTY; 1072 break; 1073 } 1074 lwkt_reltoken(&kq_token); 1075 return (error); 1076 } 1077 1078 /* 1079 * MPSAFE 1080 */ 1081 static int 1082 kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred) 1083 { 1084 struct kqueue *kq = (struct kqueue *)fp->f_data; 1085 1086 bzero((void *)st, sizeof(*st)); 1087 st->st_size = kq->kq_count; 1088 st->st_blksize = sizeof(struct kevent); 1089 st->st_mode = S_IFIFO; 1090 return (0); 1091 } 1092 1093 /* 1094 * MPSAFE 1095 */ 1096 static int 1097 kqueue_close(struct file *fp) 1098 { 1099 struct kqueue *kq = (struct kqueue *)fp->f_data; 1100 1101 kqueue_terminate(kq); 1102 1103 fp->f_data = NULL; 1104 funsetown(kq->kq_sigio); 1105 1106 kfree(kq, M_KQUEUE); 1107 return (0); 1108 } 1109 1110 static void 1111 kqueue_wakeup(struct kqueue *kq) 1112 { 1113 if (kq->kq_state & KQ_SLEEP) { 1114 kq->kq_state &= ~KQ_SLEEP; 1115 wakeup(kq); 1116 } 1117 KNOTE(&kq->kq_kqinfo.ki_note, 0); 1118 } 1119 1120 /* 1121 * Calls filterops f_attach function, acquiring mplock if filter is not 1122 * marked as FILTEROP_MPSAFE. 1123 */ 1124 static int 1125 filter_attach(struct knote *kn) 1126 { 1127 int ret; 1128 1129 if (!(kn->kn_fop->f_flags & FILTEROP_MPSAFE)) { 1130 get_mplock(); 1131 ret = kn->kn_fop->f_attach(kn); 1132 rel_mplock(); 1133 } else { 1134 ret = kn->kn_fop->f_attach(kn); 1135 } 1136 1137 return (ret); 1138 } 1139 1140 /* 1141 * Detach the knote and drop it, destroying the knote. 1142 * 1143 * Calls filterops f_detach function, acquiring mplock if filter is not 1144 * marked as FILTEROP_MPSAFE. 1145 * 1146 * This can race due to the MP lock and/or locks acquired by f_detach, 1147 * so we interlock with KN_DELETING. It is also possible to race 1148 * a create for the same reason if userland tries to delete the knote 1149 * before the create is complete. 1150 */ 1151 static void 1152 knote_detach_and_drop(struct knote *kn) 1153 { 1154 if (kn->kn_status & (KN_CREATING | KN_DELETING)) 1155 return; 1156 kn->kn_status |= KN_DELETING; 1157 1158 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { 1159 kn->kn_fop->f_detach(kn); 1160 } else { 1161 get_mplock(); 1162 kn->kn_fop->f_detach(kn); 1163 rel_mplock(); 1164 } 1165 knote_drop(kn); 1166 } 1167 1168 /* 1169 * Calls filterops f_event function, acquiring mplock if filter is not 1170 * marked as FILTEROP_MPSAFE. 1171 * 1172 * If the knote is in the middle of being created or deleted we cannot 1173 * safely call the filter op. 1174 */ 1175 static int 1176 filter_event(struct knote *kn, long hint) 1177 { 1178 int ret; 1179 1180 if (kn->kn_status & (KN_CREATING | KN_DELETING)) 1181 return(0); 1182 1183 if (!(kn->kn_fop->f_flags & FILTEROP_MPSAFE)) { 1184 get_mplock(); 1185 ret = kn->kn_fop->f_event(kn, hint); 1186 rel_mplock(); 1187 } else { 1188 ret = kn->kn_fop->f_event(kn, hint); 1189 } 1190 1191 return (ret); 1192 } 1193 1194 /* 1195 * walk down a list of knotes, activating them if their event has triggered. 1196 */ 1197 void 1198 knote(struct klist *list, long hint) 1199 { 1200 struct knote *kn; 1201 1202 lwkt_gettoken(&kq_token); 1203 SLIST_FOREACH(kn, list, kn_next) { 1204 if (filter_event(kn, hint)) 1205 KNOTE_ACTIVATE(kn); 1206 } 1207 lwkt_reltoken(&kq_token); 1208 } 1209 1210 /* 1211 * insert knote at head of klist 1212 * 1213 * Requires: kq_token 1214 */ 1215 void 1216 knote_insert(struct klist *klist, struct knote *kn) 1217 { 1218 lwkt_gettoken(&kq_token); 1219 SLIST_INSERT_HEAD(klist, kn, kn_next); 1220 lwkt_reltoken(&kq_token); 1221 } 1222 1223 /* 1224 * remove knote from a klist 1225 * 1226 * Requires: kq_token 1227 */ 1228 void 1229 knote_remove(struct klist *klist, struct knote *kn) 1230 { 1231 lwkt_gettoken(&kq_token); 1232 SLIST_REMOVE(klist, kn, knote, kn_next); 1233 lwkt_reltoken(&kq_token); 1234 } 1235 1236 /* 1237 * remove all knotes from a specified klist 1238 */ 1239 void 1240 knote_empty(struct klist *list) 1241 { 1242 struct knote *kn; 1243 1244 lwkt_gettoken(&kq_token); 1245 while ((kn = SLIST_FIRST(list)) != NULL) 1246 knote_detach_and_drop(kn); 1247 lwkt_reltoken(&kq_token); 1248 } 1249 1250 /* 1251 * remove all knotes referencing a specified fd 1252 */ 1253 void 1254 knote_fdclose(struct file *fp, struct filedesc *fdp, int fd) 1255 { 1256 struct knote *kn; 1257 1258 lwkt_gettoken(&kq_token); 1259 restart: 1260 SLIST_FOREACH(kn, &fp->f_klist, kn_link) { 1261 if (kn->kn_kq->kq_fdp == fdp && kn->kn_id == fd) { 1262 knote_detach_and_drop(kn); 1263 goto restart; 1264 } 1265 } 1266 lwkt_reltoken(&kq_token); 1267 } 1268 1269 static void 1270 knote_attach(struct knote *kn) 1271 { 1272 struct klist *list; 1273 struct kqueue *kq = kn->kn_kq; 1274 1275 if (kn->kn_fop->f_flags & FILTEROP_ISFD) { 1276 KKASSERT(kn->kn_fp); 1277 list = &kn->kn_fp->f_klist; 1278 } else { 1279 if (kq->kq_knhashmask == 0) 1280 kq->kq_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1281 &kq->kq_knhashmask); 1282 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1283 } 1284 SLIST_INSERT_HEAD(list, kn, kn_link); 1285 TAILQ_INSERT_HEAD(&kq->kq_knlist, kn, kn_kqlink); 1286 kn->kn_status = KN_CREATING; 1287 } 1288 1289 static void 1290 knote_drop(struct knote *kn) 1291 { 1292 struct kqueue *kq; 1293 struct klist *list; 1294 1295 kq = kn->kn_kq; 1296 1297 if (kn->kn_fop->f_flags & FILTEROP_ISFD) 1298 list = &kn->kn_fp->f_klist; 1299 else 1300 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1301 1302 SLIST_REMOVE(list, kn, knote, kn_link); 1303 TAILQ_REMOVE(&kq->kq_knlist, kn, kn_kqlink); 1304 if (kn->kn_status & KN_QUEUED) 1305 knote_dequeue(kn); 1306 if (kn->kn_fop->f_flags & FILTEROP_ISFD) { 1307 fdrop(kn->kn_fp); 1308 kn->kn_fp = NULL; 1309 } 1310 knote_free(kn); 1311 } 1312 1313 static void 1314 knote_enqueue(struct knote *kn) 1315 { 1316 struct kqueue *kq = kn->kn_kq; 1317 1318 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 1319 1320 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); 1321 kn->kn_status |= KN_QUEUED; 1322 ++kq->kq_count; 1323 1324 /* 1325 * Send SIGIO on request (typically set up as a mailbox signal) 1326 */ 1327 if (kq->kq_sigio && (kq->kq_state & KQ_ASYNC) && kq->kq_count == 1) 1328 pgsigio(kq->kq_sigio, SIGIO, 0); 1329 1330 kqueue_wakeup(kq); 1331 } 1332 1333 static void 1334 knote_dequeue(struct knote *kn) 1335 { 1336 struct kqueue *kq = kn->kn_kq; 1337 1338 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 1339 KKASSERT((kn->kn_status & KN_PROCESSING) == 0); 1340 1341 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); 1342 kn->kn_status &= ~KN_QUEUED; 1343 kq->kq_count--; 1344 } 1345 1346 static void 1347 knote_init(void) 1348 { 1349 knote_zone = zinit("KNOTE", sizeof(struct knote), 0, 0, 1); 1350 } 1351 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL) 1352 1353 static struct knote * 1354 knote_alloc(void) 1355 { 1356 return ((struct knote *)zalloc(knote_zone)); 1357 } 1358 1359 static void 1360 knote_free(struct knote *kn) 1361 { 1362 zfree(knote_zone, kn); 1363 } 1364