| 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 | /* |
| 59 | * Global token for kqueue subsystem |
| 60 | */ |
| 61 | struct lwkt_token kq_token = LWKT_TOKEN_INITIALIZER(kq_token); |
| 62 | SYSCTL_LONG(_lwkt, OID_AUTO, kq_collisions, |
| 63 | CTLFLAG_RW, &kq_token.t_collisions, 0, |
| 64 | "Collision counter of kq_token"); |
| 65 | |
| 66 | MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); |
| 67 | |
| 68 | struct kevent_copyin_args { |
| 69 | struct kevent_args *ka; |
| 70 | int pchanges; |
| 71 | }; |
| 72 | |
| 73 | static int kqueue_sleep(struct kqueue *kq, struct timespec *tsp); |
| 74 | static int kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, |
| 75 | struct knote *marker); |
| 76 | static int kqueue_read(struct file *fp, struct uio *uio, |
| 77 | struct ucred *cred, int flags); |
| 78 | static int kqueue_write(struct file *fp, struct uio *uio, |
| 79 | struct ucred *cred, int flags); |
| 80 | static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data, |
| 81 | struct ucred *cred, struct sysmsg *msg); |
| 82 | static int kqueue_kqfilter(struct file *fp, struct knote *kn); |
| 83 | static int kqueue_stat(struct file *fp, struct stat *st, |
| 84 | struct ucred *cred); |
| 85 | static int kqueue_close(struct file *fp); |
| 86 | static void kqueue_wakeup(struct kqueue *kq); |
| 87 | static int filter_attach(struct knote *kn); |
| 88 | static int filter_event(struct knote *kn, long hint); |
| 89 | |
| 90 | /* |
| 91 | * MPSAFE |
| 92 | */ |
| 93 | static struct fileops kqueueops = { |
| 94 | .fo_read = kqueue_read, |
| 95 | .fo_write = kqueue_write, |
| 96 | .fo_ioctl = kqueue_ioctl, |
| 97 | .fo_kqfilter = kqueue_kqfilter, |
| 98 | .fo_stat = kqueue_stat, |
| 99 | .fo_close = kqueue_close, |
| 100 | .fo_shutdown = nofo_shutdown |
| 101 | }; |
| 102 | |
| 103 | static void knote_attach(struct knote *kn); |
| 104 | static void knote_drop(struct knote *kn); |
| 105 | static void knote_detach_and_drop(struct knote *kn); |
| 106 | static void knote_enqueue(struct knote *kn); |
| 107 | static void knote_dequeue(struct knote *kn); |
| 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 int kq_ncallouts = 0; |
| 132 | static int kq_calloutmax = (4 * 1024); |
| 133 | SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, |
| 134 | &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); |
| 135 | static int kq_checkloop = 1000000; |
| 136 | SYSCTL_INT(_kern, OID_AUTO, kq_checkloop, CTLFLAG_RW, |
| 137 | &kq_checkloop, 0, "Maximum number of callouts allocated for kqueue"); |
| 138 | |
| 139 | #define KNOTE_ACTIVATE(kn) do { \ |
| 140 | kn->kn_status |= KN_ACTIVE; \ |
| 141 | if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ |
| 142 | knote_enqueue(kn); \ |
| 143 | } while(0) |
| 144 | |
| 145 | #define KN_HASHSIZE 64 /* XXX should be tunable */ |
| 146 | #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) |
| 147 | |
| 148 | extern struct filterops aio_filtops; |
| 149 | extern struct filterops sig_filtops; |
| 150 | |
| 151 | /* |
| 152 | * Table for for all system-defined filters. |
| 153 | */ |
| 154 | static struct filterops *sysfilt_ops[] = { |
| 155 | &file_filtops, /* EVFILT_READ */ |
| 156 | &file_filtops, /* EVFILT_WRITE */ |
| 157 | &aio_filtops, /* EVFILT_AIO */ |
| 158 | &file_filtops, /* EVFILT_VNODE */ |
| 159 | &proc_filtops, /* EVFILT_PROC */ |
| 160 | &sig_filtops, /* EVFILT_SIGNAL */ |
| 161 | &timer_filtops, /* EVFILT_TIMER */ |
| 162 | &file_filtops, /* EVFILT_EXCEPT */ |
| 163 | }; |
| 164 | |
| 165 | static int |
| 166 | filt_fileattach(struct knote *kn) |
| 167 | { |
| 168 | return (fo_kqfilter(kn->kn_fp, kn)); |
| 169 | } |
| 170 | |
| 171 | /* |
| 172 | * MPSAFE |
| 173 | */ |
| 174 | static int |
| 175 | kqueue_kqfilter(struct file *fp, struct knote *kn) |
| 176 | { |
| 177 | struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; |
| 178 | |
| 179 | if (kn->kn_filter != EVFILT_READ) |
| 180 | return (EOPNOTSUPP); |
| 181 | |
| 182 | kn->kn_fop = &kqread_filtops; |
| 183 | knote_insert(&kq->kq_kqinfo.ki_note, kn); |
| 184 | return (0); |
| 185 | } |
| 186 | |
| 187 | static void |
| 188 | filt_kqdetach(struct knote *kn) |
| 189 | { |
| 190 | struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; |
| 191 | |
| 192 | knote_remove(&kq->kq_kqinfo.ki_note, kn); |
| 193 | } |
| 194 | |
| 195 | /*ARGSUSED*/ |
| 196 | static int |
| 197 | filt_kqueue(struct knote *kn, long hint) |
| 198 | { |
| 199 | struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; |
| 200 | |
| 201 | kn->kn_data = kq->kq_count; |
| 202 | return (kn->kn_data > 0); |
| 203 | } |
| 204 | |
| 205 | static int |
| 206 | filt_procattach(struct knote *kn) |
| 207 | { |
| 208 | struct proc *p; |
| 209 | int immediate; |
| 210 | |
| 211 | immediate = 0; |
| 212 | p = pfind(kn->kn_id); |
| 213 | if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { |
| 214 | p = zpfind(kn->kn_id); |
| 215 | immediate = 1; |
| 216 | } |
| 217 | if (p == NULL) { |
| 218 | return (ESRCH); |
| 219 | } |
| 220 | if (!PRISON_CHECK(curthread->td_ucred, p->p_ucred)) { |
| 221 | if (p) |
| 222 | PRELE(p); |
| 223 | return (EACCES); |
| 224 | } |
| 225 | |
| 226 | lwkt_gettoken(&p->p_token); |
| 227 | kn->kn_ptr.p_proc = p; |
| 228 | kn->kn_flags |= EV_CLEAR; /* automatically set */ |
| 229 | |
| 230 | /* |
| 231 | * internal flag indicating registration done by kernel |
| 232 | */ |
| 233 | if (kn->kn_flags & EV_FLAG1) { |
| 234 | kn->kn_data = kn->kn_sdata; /* ppid */ |
| 235 | kn->kn_fflags = NOTE_CHILD; |
| 236 | kn->kn_flags &= ~EV_FLAG1; |
| 237 | } |
| 238 | |
| 239 | knote_insert(&p->p_klist, kn); |
| 240 | |
| 241 | /* |
| 242 | * Immediately activate any exit notes if the target process is a |
| 243 | * zombie. This is necessary to handle the case where the target |
| 244 | * process, e.g. a child, dies before the kevent is negistered. |
| 245 | */ |
| 246 | if (immediate && filt_proc(kn, NOTE_EXIT)) |
| 247 | KNOTE_ACTIVATE(kn); |
| 248 | lwkt_reltoken(&p->p_token); |
| 249 | PRELE(p); |
| 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 | /* |
| 334 | * The callout interlocks with callout_terminate() but can still |
| 335 | * race a deletion so if KN_DELETING is set we just don't touch |
| 336 | * the knote. |
| 337 | */ |
| 338 | static void |
| 339 | filt_timerexpire(void *knx) |
| 340 | { |
| 341 | struct knote *kn = knx; |
| 342 | struct callout *calloutp; |
| 343 | struct timeval tv; |
| 344 | int tticks; |
| 345 | |
| 346 | lwkt_gettoken(&kq_token); |
| 347 | if ((kn->kn_status & KN_DELETING) == 0) { |
| 348 | kn->kn_data++; |
| 349 | KNOTE_ACTIVATE(kn); |
| 350 | |
| 351 | if ((kn->kn_flags & EV_ONESHOT) == 0) { |
| 352 | tv.tv_sec = kn->kn_sdata / 1000; |
| 353 | tv.tv_usec = (kn->kn_sdata % 1000) * 1000; |
| 354 | tticks = tvtohz_high(&tv); |
| 355 | calloutp = (struct callout *)kn->kn_hook; |
| 356 | callout_reset(calloutp, tticks, filt_timerexpire, kn); |
| 357 | } |
| 358 | } |
| 359 | lwkt_reltoken(&kq_token); |
| 360 | } |
| 361 | |
| 362 | /* |
| 363 | * data contains amount of time to sleep, in milliseconds |
| 364 | */ |
| 365 | static int |
| 366 | filt_timerattach(struct knote *kn) |
| 367 | { |
| 368 | struct callout *calloutp; |
| 369 | struct timeval tv; |
| 370 | int tticks; |
| 371 | |
| 372 | if (kq_ncallouts >= kq_calloutmax) { |
| 373 | kn->kn_hook = NULL; |
| 374 | return (ENOMEM); |
| 375 | } |
| 376 | kq_ncallouts++; |
| 377 | |
| 378 | tv.tv_sec = kn->kn_sdata / 1000; |
| 379 | tv.tv_usec = (kn->kn_sdata % 1000) * 1000; |
| 380 | tticks = tvtohz_high(&tv); |
| 381 | |
| 382 | kn->kn_flags |= EV_CLEAR; /* automatically set */ |
| 383 | MALLOC(calloutp, struct callout *, sizeof(*calloutp), |
| 384 | M_KQUEUE, M_WAITOK); |
| 385 | callout_init(calloutp); |
| 386 | kn->kn_hook = (caddr_t)calloutp; |
| 387 | callout_reset(calloutp, tticks, filt_timerexpire, kn); |
| 388 | |
| 389 | return (0); |
| 390 | } |
| 391 | |
| 392 | /* |
| 393 | * This function is called with the knote flagged locked but it is |
| 394 | * still possible to race a callout event due to the callback blocking. |
| 395 | * We must call callout_terminate() instead of callout_stop() to deal |
| 396 | * with the race. |
| 397 | */ |
| 398 | static void |
| 399 | filt_timerdetach(struct knote *kn) |
| 400 | { |
| 401 | struct callout *calloutp; |
| 402 | |
| 403 | calloutp = (struct callout *)kn->kn_hook; |
| 404 | callout_terminate(calloutp); |
| 405 | FREE(calloutp, M_KQUEUE); |
| 406 | kq_ncallouts--; |
| 407 | } |
| 408 | |
| 409 | static int |
| 410 | filt_timer(struct knote *kn, long hint) |
| 411 | { |
| 412 | |
| 413 | return (kn->kn_data != 0); |
| 414 | } |
| 415 | |
| 416 | /* |
| 417 | * Acquire a knote, return non-zero on success, 0 on failure. |
| 418 | * |
| 419 | * If we cannot acquire the knote we sleep and return 0. The knote |
| 420 | * may be stale on return in this case and the caller must restart |
| 421 | * whatever loop they are in. |
| 422 | */ |
| 423 | static __inline |
| 424 | int |
| 425 | knote_acquire(struct knote *kn) |
| 426 | { |
| 427 | if (kn->kn_status & KN_PROCESSING) { |
| 428 | kn->kn_status |= KN_WAITING | KN_REPROCESS; |
| 429 | tsleep(kn, 0, "kqepts", hz); |
| 430 | /* knote may be stale now */ |
| 431 | return(0); |
| 432 | } |
| 433 | kn->kn_status |= KN_PROCESSING; |
| 434 | return(1); |
| 435 | } |
| 436 | |
| 437 | /* |
| 438 | * Release an acquired knote, clearing KN_PROCESSING and handling any |
| 439 | * KN_REPROCESS events. |
| 440 | * |
| 441 | * Non-zero is returned if the knote is destroyed. |
| 442 | */ |
| 443 | static __inline |
| 444 | int |
| 445 | knote_release(struct knote *kn) |
| 446 | { |
| 447 | while (kn->kn_status & KN_REPROCESS) { |
| 448 | kn->kn_status &= ~KN_REPROCESS; |
| 449 | if (kn->kn_status & KN_WAITING) { |
| 450 | kn->kn_status &= ~KN_WAITING; |
| 451 | wakeup(kn); |
| 452 | } |
| 453 | if (kn->kn_status & KN_DELETING) { |
| 454 | knote_detach_and_drop(kn); |
| 455 | return(1); |
| 456 | /* NOT REACHED */ |
| 457 | } |
| 458 | if (filter_event(kn, 0)) |
| 459 | KNOTE_ACTIVATE(kn); |
| 460 | } |
| 461 | kn->kn_status &= ~KN_PROCESSING; |
| 462 | return(0); |
| 463 | } |
| 464 | |
| 465 | /* |
| 466 | * Initialize a kqueue. |
| 467 | * |
| 468 | * NOTE: The lwp/proc code initializes a kqueue for select/poll ops. |
| 469 | * |
| 470 | * MPSAFE |
| 471 | */ |
| 472 | void |
| 473 | kqueue_init(struct kqueue *kq, struct filedesc *fdp) |
| 474 | { |
| 475 | TAILQ_INIT(&kq->kq_knpend); |
| 476 | TAILQ_INIT(&kq->kq_knlist); |
| 477 | kq->kq_count = 0; |
| 478 | kq->kq_fdp = fdp; |
| 479 | SLIST_INIT(&kq->kq_kqinfo.ki_note); |
| 480 | } |
| 481 | |
| 482 | /* |
| 483 | * Terminate a kqueue. Freeing the actual kq itself is left up to the |
| 484 | * caller (it might be embedded in a lwp so we don't do it here). |
| 485 | * |
| 486 | * The kq's knlist must be completely eradicated so block on any |
| 487 | * processing races. |
| 488 | */ |
| 489 | void |
| 490 | kqueue_terminate(struct kqueue *kq) |
| 491 | { |
| 492 | struct knote *kn; |
| 493 | |
| 494 | lwkt_gettoken(&kq_token); |
| 495 | while ((kn = TAILQ_FIRST(&kq->kq_knlist)) != NULL) { |
| 496 | if (knote_acquire(kn)) |
| 497 | knote_detach_and_drop(kn); |
| 498 | } |
| 499 | if (kq->kq_knhash) { |
| 500 | kfree(kq->kq_knhash, M_KQUEUE); |
| 501 | kq->kq_knhash = NULL; |
| 502 | kq->kq_knhashmask = 0; |
| 503 | } |
| 504 | lwkt_reltoken(&kq_token); |
| 505 | } |
| 506 | |
| 507 | /* |
| 508 | * MPSAFE |
| 509 | */ |
| 510 | int |
| 511 | sys_kqueue(struct kqueue_args *uap) |
| 512 | { |
| 513 | struct thread *td = curthread; |
| 514 | struct kqueue *kq; |
| 515 | struct file *fp; |
| 516 | int fd, error; |
| 517 | |
| 518 | error = falloc(td->td_lwp, &fp, &fd); |
| 519 | if (error) |
| 520 | return (error); |
| 521 | fp->f_flag = FREAD | FWRITE; |
| 522 | fp->f_type = DTYPE_KQUEUE; |
| 523 | fp->f_ops = &kqueueops; |
| 524 | |
| 525 | kq = kmalloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO); |
| 526 | kqueue_init(kq, td->td_proc->p_fd); |
| 527 | fp->f_data = kq; |
| 528 | |
| 529 | fsetfd(kq->kq_fdp, fp, fd); |
| 530 | uap->sysmsg_result = fd; |
| 531 | fdrop(fp); |
| 532 | return (error); |
| 533 | } |
| 534 | |
| 535 | /* |
| 536 | * Copy 'count' items into the destination list pointed to by uap->eventlist. |
| 537 | */ |
| 538 | static int |
| 539 | kevent_copyout(void *arg, struct kevent *kevp, int count, int *res) |
| 540 | { |
| 541 | struct kevent_copyin_args *kap; |
| 542 | int error; |
| 543 | |
| 544 | kap = (struct kevent_copyin_args *)arg; |
| 545 | |
| 546 | error = copyout(kevp, kap->ka->eventlist, count * sizeof(*kevp)); |
| 547 | if (error == 0) { |
| 548 | kap->ka->eventlist += count; |
| 549 | *res += count; |
| 550 | } else { |
| 551 | *res = -1; |
| 552 | } |
| 553 | |
| 554 | return (error); |
| 555 | } |
| 556 | |
| 557 | /* |
| 558 | * Copy at most 'max' items from the list pointed to by kap->changelist, |
| 559 | * return number of items in 'events'. |
| 560 | */ |
| 561 | static int |
| 562 | kevent_copyin(void *arg, struct kevent *kevp, int max, int *events) |
| 563 | { |
| 564 | struct kevent_copyin_args *kap; |
| 565 | int error, count; |
| 566 | |
| 567 | kap = (struct kevent_copyin_args *)arg; |
| 568 | |
| 569 | count = min(kap->ka->nchanges - kap->pchanges, max); |
| 570 | error = copyin(kap->ka->changelist, kevp, count * sizeof *kevp); |
| 571 | if (error == 0) { |
| 572 | kap->ka->changelist += count; |
| 573 | kap->pchanges += count; |
| 574 | *events = count; |
| 575 | } |
| 576 | |
| 577 | return (error); |
| 578 | } |
| 579 | |
| 580 | /* |
| 581 | * MPSAFE |
| 582 | */ |
| 583 | int |
| 584 | kern_kevent(struct kqueue *kq, int nevents, int *res, void *uap, |
| 585 | k_copyin_fn kevent_copyinfn, k_copyout_fn kevent_copyoutfn, |
| 586 | struct timespec *tsp_in) |
| 587 | { |
| 588 | struct kevent *kevp; |
| 589 | struct timespec *tsp; |
| 590 | int i, n, total, error, nerrors = 0; |
| 591 | int lres; |
| 592 | int limit = kq_checkloop; |
| 593 | struct kevent kev[KQ_NEVENTS]; |
| 594 | struct knote marker; |
| 595 | |
| 596 | tsp = tsp_in; |
| 597 | *res = 0; |
| 598 | |
| 599 | lwkt_gettoken(&kq_token); |
| 600 | for ( ;; ) { |
| 601 | n = 0; |
| 602 | error = kevent_copyinfn(uap, kev, KQ_NEVENTS, &n); |
| 603 | if (error) |
| 604 | goto done; |
| 605 | if (n == 0) |
| 606 | break; |
| 607 | for (i = 0; i < n; i++) { |
| 608 | kevp = &kev[i]; |
| 609 | kevp->flags &= ~EV_SYSFLAGS; |
| 610 | error = kqueue_register(kq, kevp); |
| 611 | |
| 612 | /* |
| 613 | * If a registration returns an error we |
| 614 | * immediately post the error. The kevent() |
| 615 | * call itself will fail with the error if |
| 616 | * no space is available for posting. |
| 617 | * |
| 618 | * Such errors normally bypass the timeout/blocking |
| 619 | * code. However, if the copyoutfn function refuses |
| 620 | * to post the error (see sys_poll()), then we |
| 621 | * ignore it too. |
| 622 | */ |
| 623 | if (error) { |
| 624 | kevp->flags = EV_ERROR; |
| 625 | kevp->data = error; |
| 626 | lres = *res; |
| 627 | kevent_copyoutfn(uap, kevp, 1, res); |
| 628 | if (*res < 0) { |
| 629 | goto done; |
| 630 | } else if (lres != *res) { |
| 631 | nevents--; |
| 632 | nerrors++; |
| 633 | } |
| 634 | } |
| 635 | } |
| 636 | } |
| 637 | if (nerrors) { |
| 638 | error = 0; |
| 639 | goto done; |
| 640 | } |
| 641 | |
| 642 | /* |
| 643 | * Acquire/wait for events - setup timeout |
| 644 | */ |
| 645 | if (tsp != NULL) { |
| 646 | struct timespec ats; |
| 647 | |
| 648 | if (tsp->tv_sec || tsp->tv_nsec) { |
| 649 | nanouptime(&ats); |
| 650 | timespecadd(tsp, &ats); /* tsp = target time */ |
| 651 | } |
| 652 | } |
| 653 | |
| 654 | /* |
| 655 | * Loop as required. |
| 656 | * |
| 657 | * Collect as many events as we can. Sleeping on successive |
| 658 | * loops is disabled if copyoutfn has incremented (*res). |
| 659 | * |
| 660 | * The loop stops if an error occurs, all events have been |
| 661 | * scanned (the marker has been reached), or fewer than the |
| 662 | * maximum number of events is found. |
| 663 | * |
| 664 | * The copyoutfn function does not have to increment (*res) in |
| 665 | * order for the loop to continue. |
| 666 | * |
| 667 | * NOTE: doselect() usually passes 0x7FFFFFFF for nevents. |
| 668 | */ |
| 669 | total = 0; |
| 670 | error = 0; |
| 671 | marker.kn_filter = EVFILT_MARKER; |
| 672 | marker.kn_status = KN_PROCESSING; |
| 673 | TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); |
| 674 | while ((n = nevents - total) > 0) { |
| 675 | if (n > KQ_NEVENTS) |
| 676 | n = KQ_NEVENTS; |
| 677 | |
| 678 | /* |
| 679 | * If no events are pending sleep until timeout (if any) |
| 680 | * or an event occurs. |
| 681 | * |
| 682 | * After the sleep completes the marker is moved to the |
| 683 | * end of the list, making any received events available |
| 684 | * to our scan. |
| 685 | */ |
| 686 | if (kq->kq_count == 0 && *res == 0) { |
| 687 | error = kqueue_sleep(kq, tsp); |
| 688 | if (error) |
| 689 | break; |
| 690 | |
| 691 | TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); |
| 692 | TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); |
| 693 | } |
| 694 | |
| 695 | /* |
| 696 | * Process all received events |
| 697 | * Account for all non-spurious events in our total |
| 698 | */ |
| 699 | i = kqueue_scan(kq, kev, n, &marker); |
| 700 | if (i) { |
| 701 | lres = *res; |
| 702 | error = kevent_copyoutfn(uap, kev, i, res); |
| 703 | total += *res - lres; |
| 704 | if (error) |
| 705 | break; |
| 706 | } |
| 707 | if (limit && --limit == 0) |
| 708 | panic("kqueue: checkloop failed i=%d", i); |
| 709 | |
| 710 | /* |
| 711 | * Normally when fewer events are returned than requested |
| 712 | * we can stop. However, if only spurious events were |
| 713 | * collected the copyout will not bump (*res) and we have |
| 714 | * to continue. |
| 715 | */ |
| 716 | if (i < n && *res) |
| 717 | break; |
| 718 | |
| 719 | /* |
| 720 | * Deal with an edge case where spurious events can cause |
| 721 | * a loop to occur without moving the marker. This can |
| 722 | * prevent kqueue_scan() from picking up new events which |
| 723 | * race us. We must be sure to move the marker for this |
| 724 | * case. |
| 725 | * |
| 726 | * NOTE: We do not want to move the marker if events |
| 727 | * were scanned because normal kqueue operations |
| 728 | * may reactivate events. Moving the marker in |
| 729 | * that case could result in duplicates for the |
| 730 | * same event. |
| 731 | */ |
| 732 | if (i == 0) { |
| 733 | TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); |
| 734 | TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); |
| 735 | } |
| 736 | } |
| 737 | TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); |
| 738 | |
| 739 | /* Timeouts do not return EWOULDBLOCK. */ |
| 740 | if (error == EWOULDBLOCK) |
| 741 | error = 0; |
| 742 | |
| 743 | done: |
| 744 | lwkt_reltoken(&kq_token); |
| 745 | return (error); |
| 746 | } |
| 747 | |
| 748 | /* |
| 749 | * MPALMOSTSAFE |
| 750 | */ |
| 751 | int |
| 752 | sys_kevent(struct kevent_args *uap) |
| 753 | { |
| 754 | struct thread *td = curthread; |
| 755 | struct proc *p = td->td_proc; |
| 756 | struct timespec ts, *tsp; |
| 757 | struct kqueue *kq; |
| 758 | struct file *fp = NULL; |
| 759 | struct kevent_copyin_args *kap, ka; |
| 760 | int error; |
| 761 | |
| 762 | if (uap->timeout) { |
| 763 | error = copyin(uap->timeout, &ts, sizeof(ts)); |
| 764 | if (error) |
| 765 | return (error); |
| 766 | tsp = &ts; |
| 767 | } else { |
| 768 | tsp = NULL; |
| 769 | } |
| 770 | |
| 771 | fp = holdfp(p->p_fd, uap->fd, -1); |
| 772 | if (fp == NULL) |
| 773 | return (EBADF); |
| 774 | if (fp->f_type != DTYPE_KQUEUE) { |
| 775 | fdrop(fp); |
| 776 | return (EBADF); |
| 777 | } |
| 778 | |
| 779 | kq = (struct kqueue *)fp->f_data; |
| 780 | |
| 781 | kap = &ka; |
| 782 | kap->ka = uap; |
| 783 | kap->pchanges = 0; |
| 784 | |
| 785 | error = kern_kevent(kq, uap->nevents, &uap->sysmsg_result, kap, |
| 786 | kevent_copyin, kevent_copyout, tsp); |
| 787 | |
| 788 | fdrop(fp); |
| 789 | |
| 790 | return (error); |
| 791 | } |
| 792 | |
| 793 | int |
| 794 | kqueue_register(struct kqueue *kq, struct kevent *kev) |
| 795 | { |
| 796 | struct filedesc *fdp = kq->kq_fdp; |
| 797 | struct filterops *fops; |
| 798 | struct file *fp = NULL; |
| 799 | struct knote *kn = NULL; |
| 800 | int error = 0; |
| 801 | |
| 802 | if (kev->filter < 0) { |
| 803 | if (kev->filter + EVFILT_SYSCOUNT < 0) |
| 804 | return (EINVAL); |
| 805 | fops = sysfilt_ops[~kev->filter]; /* to 0-base index */ |
| 806 | } else { |
| 807 | /* |
| 808 | * XXX |
| 809 | * filter attach routine is responsible for insuring that |
| 810 | * the identifier can be attached to it. |
| 811 | */ |
| 812 | kprintf("unknown filter: %d\n", kev->filter); |
| 813 | return (EINVAL); |
| 814 | } |
| 815 | |
| 816 | lwkt_gettoken(&kq_token); |
| 817 | if (fops->f_flags & FILTEROP_ISFD) { |
| 818 | /* validate descriptor */ |
| 819 | fp = holdfp(fdp, kev->ident, -1); |
| 820 | if (fp == NULL) { |
| 821 | lwkt_reltoken(&kq_token); |
| 822 | return (EBADF); |
| 823 | } |
| 824 | |
| 825 | again1: |
| 826 | SLIST_FOREACH(kn, &fp->f_klist, kn_link) { |
| 827 | if (kn->kn_kq == kq && |
| 828 | kn->kn_filter == kev->filter && |
| 829 | kn->kn_id == kev->ident) { |
| 830 | if (knote_acquire(kn) == 0) |
| 831 | goto again1; |
| 832 | break; |
| 833 | } |
| 834 | } |
| 835 | } else { |
| 836 | if (kq->kq_knhashmask) { |
| 837 | struct klist *list; |
| 838 | |
| 839 | list = &kq->kq_knhash[ |
| 840 | KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; |
| 841 | again2: |
| 842 | SLIST_FOREACH(kn, list, kn_link) { |
| 843 | if (kn->kn_id == kev->ident && |
| 844 | kn->kn_filter == kev->filter) { |
| 845 | if (knote_acquire(kn) == 0) |
| 846 | goto again2; |
| 847 | break; |
| 848 | } |
| 849 | } |
| 850 | } |
| 851 | } |
| 852 | |
| 853 | /* |
| 854 | * NOTE: At this point if kn is non-NULL we will have acquired |
| 855 | * it and set KN_PROCESSING. |
| 856 | */ |
| 857 | if (kn == NULL && ((kev->flags & EV_ADD) == 0)) { |
| 858 | error = ENOENT; |
| 859 | goto done; |
| 860 | } |
| 861 | |
| 862 | /* |
| 863 | * kn now contains the matching knote, or NULL if no match |
| 864 | */ |
| 865 | if (kev->flags & EV_ADD) { |
| 866 | if (kn == NULL) { |
| 867 | kn = knote_alloc(); |
| 868 | if (kn == NULL) { |
| 869 | error = ENOMEM; |
| 870 | goto done; |
| 871 | } |
| 872 | kn->kn_fp = fp; |
| 873 | kn->kn_kq = kq; |
| 874 | kn->kn_fop = fops; |
| 875 | |
| 876 | /* |
| 877 | * apply reference count to knote structure, and |
| 878 | * do not release it at the end of this routine. |
| 879 | */ |
| 880 | fp = NULL; |
| 881 | |
| 882 | kn->kn_sfflags = kev->fflags; |
| 883 | kn->kn_sdata = kev->data; |
| 884 | kev->fflags = 0; |
| 885 | kev->data = 0; |
| 886 | kn->kn_kevent = *kev; |
| 887 | |
| 888 | /* |
| 889 | * KN_PROCESSING prevents the knote from getting |
| 890 | * ripped out from under us while we are trying |
| 891 | * to attach it, in case the attach blocks. |
| 892 | */ |
| 893 | kn->kn_status = KN_PROCESSING; |
| 894 | knote_attach(kn); |
| 895 | if ((error = filter_attach(kn)) != 0) { |
| 896 | kn->kn_status |= KN_DELETING | KN_REPROCESS; |
| 897 | knote_drop(kn); |
| 898 | goto done; |
| 899 | } |
| 900 | |
| 901 | /* |
| 902 | * Interlock against close races which either tried |
| 903 | * to remove our knote while we were blocked or missed |
| 904 | * it entirely prior to our attachment. We do not |
| 905 | * want to end up with a knote on a closed descriptor. |
| 906 | */ |
| 907 | if ((fops->f_flags & FILTEROP_ISFD) && |
| 908 | checkfdclosed(fdp, kev->ident, kn->kn_fp)) { |
| 909 | kn->kn_status |= KN_DELETING | KN_REPROCESS; |
| 910 | } |
| 911 | } else { |
| 912 | /* |
| 913 | * The user may change some filter values after the |
| 914 | * initial EV_ADD, but doing so will not reset any |
| 915 | * filter which have already been triggered. |
| 916 | */ |
| 917 | KKASSERT(kn->kn_status & KN_PROCESSING); |
| 918 | kn->kn_sfflags = kev->fflags; |
| 919 | kn->kn_sdata = kev->data; |
| 920 | kn->kn_kevent.udata = kev->udata; |
| 921 | } |
| 922 | |
| 923 | /* |
| 924 | * Execute the filter event to immediately activate the |
| 925 | * knote if necessary. If reprocessing events are pending |
| 926 | * due to blocking above we do not run the filter here |
| 927 | * but instead let knote_release() do it. Otherwise we |
| 928 | * might run the filter on a deleted event. |
| 929 | */ |
| 930 | if ((kn->kn_status & KN_REPROCESS) == 0) { |
| 931 | if (filter_event(kn, 0)) |
| 932 | KNOTE_ACTIVATE(kn); |
| 933 | } |
| 934 | } else if (kev->flags & EV_DELETE) { |
| 935 | /* |
| 936 | * Delete the existing knote |
| 937 | */ |
| 938 | knote_detach_and_drop(kn); |
| 939 | goto done; |
| 940 | } |
| 941 | |
| 942 | /* |
| 943 | * Disablement does not deactivate a knote here. |
| 944 | */ |
| 945 | if ((kev->flags & EV_DISABLE) && |
| 946 | ((kn->kn_status & KN_DISABLED) == 0)) { |
| 947 | kn->kn_status |= KN_DISABLED; |
| 948 | } |
| 949 | |
| 950 | /* |
| 951 | * Re-enablement may have to immediately enqueue an active knote. |
| 952 | */ |
| 953 | if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { |
| 954 | kn->kn_status &= ~KN_DISABLED; |
| 955 | if ((kn->kn_status & KN_ACTIVE) && |
| 956 | ((kn->kn_status & KN_QUEUED) == 0)) { |
| 957 | knote_enqueue(kn); |
| 958 | } |
| 959 | } |
| 960 | |
| 961 | /* |
| 962 | * Handle any required reprocessing |
| 963 | */ |
| 964 | knote_release(kn); |
| 965 | /* kn may be invalid now */ |
| 966 | |
| 967 | done: |
| 968 | lwkt_reltoken(&kq_token); |
| 969 | if (fp != NULL) |
| 970 | fdrop(fp); |
| 971 | return (error); |
| 972 | } |
| 973 | |
| 974 | /* |
| 975 | * Block as necessary until the target time is reached. |
| 976 | * If tsp is NULL we block indefinitely. If tsp->ts_secs/nsecs are both |
| 977 | * 0 we do not block at all. |
| 978 | */ |
| 979 | static int |
| 980 | kqueue_sleep(struct kqueue *kq, struct timespec *tsp) |
| 981 | { |
| 982 | int error = 0; |
| 983 | |
| 984 | if (tsp == NULL) { |
| 985 | kq->kq_state |= KQ_SLEEP; |
| 986 | error = tsleep(kq, PCATCH, "kqread", 0); |
| 987 | } else if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) { |
| 988 | error = EWOULDBLOCK; |
| 989 | } else { |
| 990 | struct timespec ats; |
| 991 | struct timespec atx = *tsp; |
| 992 | int timeout; |
| 993 | |
| 994 | nanouptime(&ats); |
| 995 | timespecsub(&atx, &ats); |
| 996 | if (ats.tv_sec < 0) { |
| 997 | error = EWOULDBLOCK; |
| 998 | } else { |
| 999 | timeout = atx.tv_sec > 24 * 60 * 60 ? |
| 1000 | 24 * 60 * 60 * hz : tstohz_high(&atx); |
| 1001 | kq->kq_state |= KQ_SLEEP; |
| 1002 | error = tsleep(kq, PCATCH, "kqread", timeout); |
| 1003 | } |
| 1004 | } |
| 1005 | |
| 1006 | /* don't restart after signals... */ |
| 1007 | if (error == ERESTART) |
| 1008 | return (EINTR); |
| 1009 | |
| 1010 | return (error); |
| 1011 | } |
| 1012 | |
| 1013 | /* |
| 1014 | * Scan the kqueue, return the number of active events placed in kevp up |
| 1015 | * to count. |
| 1016 | * |
| 1017 | * Continuous mode events may get recycled, do not continue scanning past |
| 1018 | * marker unless no events have been collected. |
| 1019 | */ |
| 1020 | static int |
| 1021 | kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, |
| 1022 | struct knote *marker) |
| 1023 | { |
| 1024 | struct knote *kn, local_marker; |
| 1025 | int total; |
| 1026 | |
| 1027 | total = 0; |
| 1028 | local_marker.kn_filter = EVFILT_MARKER; |
| 1029 | local_marker.kn_status = KN_PROCESSING; |
| 1030 | |
| 1031 | /* |
| 1032 | * Collect events. |
| 1033 | */ |
| 1034 | TAILQ_INSERT_HEAD(&kq->kq_knpend, &local_marker, kn_tqe); |
| 1035 | while (count) { |
| 1036 | kn = TAILQ_NEXT(&local_marker, kn_tqe); |
| 1037 | if (kn->kn_filter == EVFILT_MARKER) { |
| 1038 | /* Marker reached, we are done */ |
| 1039 | if (kn == marker) |
| 1040 | break; |
| 1041 | |
| 1042 | /* Move local marker past some other threads marker */ |
| 1043 | kn = TAILQ_NEXT(kn, kn_tqe); |
| 1044 | TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); |
| 1045 | TAILQ_INSERT_BEFORE(kn, &local_marker, kn_tqe); |
| 1046 | continue; |
| 1047 | } |
| 1048 | |
| 1049 | /* |
| 1050 | * We can't skip a knote undergoing processing, otherwise |
| 1051 | * we risk not returning it when the user process expects |
| 1052 | * it should be returned. Sleep and retry. |
| 1053 | */ |
| 1054 | if (knote_acquire(kn) == 0) |
| 1055 | continue; |
| 1056 | |
| 1057 | /* |
| 1058 | * Remove the event for processing. |
| 1059 | * |
| 1060 | * WARNING! We must leave KN_QUEUED set to prevent the |
| 1061 | * event from being KNOTE_ACTIVATE()d while |
| 1062 | * the queue state is in limbo, in case we |
| 1063 | * block. |
| 1064 | * |
| 1065 | * WARNING! We must set KN_PROCESSING to avoid races |
| 1066 | * against deletion or another thread's |
| 1067 | * processing. |
| 1068 | */ |
| 1069 | TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); |
| 1070 | kq->kq_count--; |
| 1071 | |
| 1072 | /* |
| 1073 | * We have to deal with an extremely important race against |
| 1074 | * file descriptor close()s here. The file descriptor can |
| 1075 | * disappear MPSAFE, and there is a small window of |
| 1076 | * opportunity between that and the call to knote_fdclose(). |
| 1077 | * |
| 1078 | * If we hit that window here while doselect or dopoll is |
| 1079 | * trying to delete a spurious event they will not be able |
| 1080 | * to match up the event against a knote and will go haywire. |
| 1081 | */ |
| 1082 | if ((kn->kn_fop->f_flags & FILTEROP_ISFD) && |
| 1083 | checkfdclosed(kq->kq_fdp, kn->kn_kevent.ident, kn->kn_fp)) { |
| 1084 | kn->kn_status |= KN_DELETING | KN_REPROCESS; |
| 1085 | } |
| 1086 | |
| 1087 | if (kn->kn_status & KN_DISABLED) { |
| 1088 | /* |
| 1089 | * If disabled we ensure the event is not queued |
| 1090 | * but leave its active bit set. On re-enablement |
| 1091 | * the event may be immediately triggered. |
| 1092 | */ |
| 1093 | kn->kn_status &= ~KN_QUEUED; |
| 1094 | } else if ((kn->kn_flags & EV_ONESHOT) == 0 && |
| 1095 | (kn->kn_status & KN_DELETING) == 0 && |
| 1096 | filter_event(kn, 0) == 0) { |
| 1097 | /* |
| 1098 | * If not running in one-shot mode and the event |
| 1099 | * is no longer present we ensure it is removed |
| 1100 | * from the queue and ignore it. |
| 1101 | */ |
| 1102 | kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); |
| 1103 | } else { |
| 1104 | /* |
| 1105 | * Post the event |
| 1106 | */ |
| 1107 | *kevp++ = kn->kn_kevent; |
| 1108 | ++total; |
| 1109 | --count; |
| 1110 | |
| 1111 | if (kn->kn_flags & EV_ONESHOT) { |
| 1112 | kn->kn_status &= ~KN_QUEUED; |
| 1113 | kn->kn_status |= KN_DELETING | KN_REPROCESS; |
| 1114 | } else if (kn->kn_flags & EV_CLEAR) { |
| 1115 | kn->kn_data = 0; |
| 1116 | kn->kn_fflags = 0; |
| 1117 | kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); |
| 1118 | } else { |
| 1119 | TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); |
| 1120 | kq->kq_count++; |
| 1121 | } |
| 1122 | } |
| 1123 | |
| 1124 | /* |
| 1125 | * Handle any post-processing states |
| 1126 | */ |
| 1127 | knote_release(kn); |
| 1128 | } |
| 1129 | TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); |
| 1130 | |
| 1131 | return (total); |
| 1132 | } |
| 1133 | |
| 1134 | /* |
| 1135 | * XXX |
| 1136 | * This could be expanded to call kqueue_scan, if desired. |
| 1137 | * |
| 1138 | * MPSAFE |
| 1139 | */ |
| 1140 | static int |
| 1141 | kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags) |
| 1142 | { |
| 1143 | return (ENXIO); |
| 1144 | } |
| 1145 | |
| 1146 | /* |
| 1147 | * MPSAFE |
| 1148 | */ |
| 1149 | static int |
| 1150 | kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags) |
| 1151 | { |
| 1152 | return (ENXIO); |
| 1153 | } |
| 1154 | |
| 1155 | /* |
| 1156 | * MPALMOSTSAFE |
| 1157 | */ |
| 1158 | static int |
| 1159 | kqueue_ioctl(struct file *fp, u_long com, caddr_t data, |
| 1160 | struct ucred *cred, struct sysmsg *msg) |
| 1161 | { |
| 1162 | struct kqueue *kq; |
| 1163 | int error; |
| 1164 | |
| 1165 | lwkt_gettoken(&kq_token); |
| 1166 | kq = (struct kqueue *)fp->f_data; |
| 1167 | |
| 1168 | switch(com) { |
| 1169 | case FIOASYNC: |
| 1170 | if (*(int *)data) |
| 1171 | kq->kq_state |= KQ_ASYNC; |
| 1172 | else |
| 1173 | kq->kq_state &= ~KQ_ASYNC; |
| 1174 | error = 0; |
| 1175 | break; |
| 1176 | case FIOSETOWN: |
| 1177 | error = fsetown(*(int *)data, &kq->kq_sigio); |
| 1178 | break; |
| 1179 | default: |
| 1180 | error = ENOTTY; |
| 1181 | break; |
| 1182 | } |
| 1183 | lwkt_reltoken(&kq_token); |
| 1184 | return (error); |
| 1185 | } |
| 1186 | |
| 1187 | /* |
| 1188 | * MPSAFE |
| 1189 | */ |
| 1190 | static int |
| 1191 | kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred) |
| 1192 | { |
| 1193 | struct kqueue *kq = (struct kqueue *)fp->f_data; |
| 1194 | |
| 1195 | bzero((void *)st, sizeof(*st)); |
| 1196 | st->st_size = kq->kq_count; |
| 1197 | st->st_blksize = sizeof(struct kevent); |
| 1198 | st->st_mode = S_IFIFO; |
| 1199 | return (0); |
| 1200 | } |
| 1201 | |
| 1202 | /* |
| 1203 | * MPSAFE |
| 1204 | */ |
| 1205 | static int |
| 1206 | kqueue_close(struct file *fp) |
| 1207 | { |
| 1208 | struct kqueue *kq = (struct kqueue *)fp->f_data; |
| 1209 | |
| 1210 | kqueue_terminate(kq); |
| 1211 | |
| 1212 | fp->f_data = NULL; |
| 1213 | funsetown(&kq->kq_sigio); |
| 1214 | |
| 1215 | kfree(kq, M_KQUEUE); |
| 1216 | return (0); |
| 1217 | } |
| 1218 | |
| 1219 | static void |
| 1220 | kqueue_wakeup(struct kqueue *kq) |
| 1221 | { |
| 1222 | if (kq->kq_state & KQ_SLEEP) { |
| 1223 | kq->kq_state &= ~KQ_SLEEP; |
| 1224 | wakeup(kq); |
| 1225 | } |
| 1226 | KNOTE(&kq->kq_kqinfo.ki_note, 0); |
| 1227 | } |
| 1228 | |
| 1229 | /* |
| 1230 | * Calls filterops f_attach function, acquiring mplock if filter is not |
| 1231 | * marked as FILTEROP_MPSAFE. |
| 1232 | */ |
| 1233 | static int |
| 1234 | filter_attach(struct knote *kn) |
| 1235 | { |
| 1236 | int ret; |
| 1237 | |
| 1238 | if (!(kn->kn_fop->f_flags & FILTEROP_MPSAFE)) { |
| 1239 | get_mplock(); |
| 1240 | ret = kn->kn_fop->f_attach(kn); |
| 1241 | rel_mplock(); |
| 1242 | } else { |
| 1243 | ret = kn->kn_fop->f_attach(kn); |
| 1244 | } |
| 1245 | |
| 1246 | return (ret); |
| 1247 | } |
| 1248 | |
| 1249 | /* |
| 1250 | * Detach the knote and drop it, destroying the knote. |
| 1251 | * |
| 1252 | * Calls filterops f_detach function, acquiring mplock if filter is not |
| 1253 | * marked as FILTEROP_MPSAFE. |
| 1254 | */ |
| 1255 | static void |
| 1256 | knote_detach_and_drop(struct knote *kn) |
| 1257 | { |
| 1258 | kn->kn_status |= KN_DELETING | KN_REPROCESS; |
| 1259 | if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { |
| 1260 | kn->kn_fop->f_detach(kn); |
| 1261 | } else { |
| 1262 | get_mplock(); |
| 1263 | kn->kn_fop->f_detach(kn); |
| 1264 | rel_mplock(); |
| 1265 | } |
| 1266 | knote_drop(kn); |
| 1267 | } |
| 1268 | |
| 1269 | /* |
| 1270 | * Calls filterops f_event function, acquiring mplock if filter is not |
| 1271 | * marked as FILTEROP_MPSAFE. |
| 1272 | * |
| 1273 | * If the knote is in the middle of being created or deleted we cannot |
| 1274 | * safely call the filter op. |
| 1275 | */ |
| 1276 | static int |
| 1277 | filter_event(struct knote *kn, long hint) |
| 1278 | { |
| 1279 | int ret; |
| 1280 | |
| 1281 | if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { |
| 1282 | ret = kn->kn_fop->f_event(kn, hint); |
| 1283 | } else { |
| 1284 | get_mplock(); |
| 1285 | ret = kn->kn_fop->f_event(kn, hint); |
| 1286 | rel_mplock(); |
| 1287 | } |
| 1288 | return (ret); |
| 1289 | } |
| 1290 | |
| 1291 | /* |
| 1292 | * Walk down a list of knotes, activating them if their event has triggered. |
| 1293 | * |
| 1294 | * If we encounter any knotes which are undergoing processing we just mark |
| 1295 | * them for reprocessing and do not try to [re]activate the knote. However, |
| 1296 | * if a hint is being passed we have to wait and that makes things a bit |
| 1297 | * sticky. |
| 1298 | */ |
| 1299 | void |
| 1300 | knote(struct klist *list, long hint) |
| 1301 | { |
| 1302 | struct knote *kn; |
| 1303 | |
| 1304 | lwkt_gettoken(&kq_token); |
| 1305 | restart: |
| 1306 | SLIST_FOREACH(kn, list, kn_next) { |
| 1307 | if (kn->kn_status & KN_PROCESSING) { |
| 1308 | /* |
| 1309 | * Someone else is processing the knote, ask the |
| 1310 | * other thread to reprocess it and don't mess |
| 1311 | * with it otherwise. |
| 1312 | */ |
| 1313 | if (hint == 0) { |
| 1314 | kn->kn_status |= KN_REPROCESS; |
| 1315 | continue; |
| 1316 | } |
| 1317 | |
| 1318 | /* |
| 1319 | * If the hint is non-zero we have to wait or risk |
| 1320 | * losing the state the caller is trying to update. |
| 1321 | * |
| 1322 | * XXX This is a real problem, certain process |
| 1323 | * and signal filters will bump kn_data for |
| 1324 | * already-processed notes more than once if |
| 1325 | * we restart the list scan. FIXME. |
| 1326 | */ |
| 1327 | kn->kn_status |= KN_WAITING | KN_REPROCESS; |
| 1328 | tsleep(kn, 0, "knotec", hz); |
| 1329 | goto restart; |
| 1330 | } |
| 1331 | |
| 1332 | /* |
| 1333 | * Become the reprocessing master ourselves. |
| 1334 | * |
| 1335 | * If hint is non-zer running the event is mandatory |
| 1336 | * when not deleting so do it whether reprocessing is |
| 1337 | * set or not. |
| 1338 | */ |
| 1339 | kn->kn_status |= KN_PROCESSING; |
| 1340 | if ((kn->kn_status & KN_DELETING) == 0) { |
| 1341 | if (filter_event(kn, hint)) |
| 1342 | KNOTE_ACTIVATE(kn); |
| 1343 | } |
| 1344 | if (knote_release(kn)) |
| 1345 | goto restart; |
| 1346 | } |
| 1347 | lwkt_reltoken(&kq_token); |
| 1348 | } |
| 1349 | |
| 1350 | /* |
| 1351 | * Insert knote at head of klist. |
| 1352 | * |
| 1353 | * This function may only be called via a filter function and thus |
| 1354 | * kq_token should already be held and marked for processing. |
| 1355 | */ |
| 1356 | void |
| 1357 | knote_insert(struct klist *klist, struct knote *kn) |
| 1358 | { |
| 1359 | KKASSERT(kn->kn_status & KN_PROCESSING); |
| 1360 | ASSERT_LWKT_TOKEN_HELD(&kq_token); |
| 1361 | SLIST_INSERT_HEAD(klist, kn, kn_next); |
| 1362 | } |
| 1363 | |
| 1364 | /* |
| 1365 | * Remove knote from a klist |
| 1366 | * |
| 1367 | * This function may only be called via a filter function and thus |
| 1368 | * kq_token should already be held and marked for processing. |
| 1369 | */ |
| 1370 | void |
| 1371 | knote_remove(struct klist *klist, struct knote *kn) |
| 1372 | { |
| 1373 | KKASSERT(kn->kn_status & KN_PROCESSING); |
| 1374 | ASSERT_LWKT_TOKEN_HELD(&kq_token); |
| 1375 | SLIST_REMOVE(klist, kn, knote, kn_next); |
| 1376 | } |
| 1377 | |
| 1378 | /* |
| 1379 | * Remove all knotes from a specified klist |
| 1380 | * |
| 1381 | * Only called from aio. |
| 1382 | */ |
| 1383 | void |
| 1384 | knote_empty(struct klist *list) |
| 1385 | { |
| 1386 | struct knote *kn; |
| 1387 | |
| 1388 | lwkt_gettoken(&kq_token); |
| 1389 | while ((kn = SLIST_FIRST(list)) != NULL) { |
| 1390 | if (knote_acquire(kn)) |
| 1391 | knote_detach_and_drop(kn); |
| 1392 | } |
| 1393 | lwkt_reltoken(&kq_token); |
| 1394 | } |
| 1395 | |
| 1396 | void |
| 1397 | knote_assume_knotes(struct kqinfo *src, struct kqinfo *dst, |
| 1398 | struct filterops *ops, void *hook) |
| 1399 | { |
| 1400 | struct knote *kn; |
| 1401 | |
| 1402 | lwkt_gettoken(&kq_token); |
| 1403 | while ((kn = SLIST_FIRST(&src->ki_note)) != NULL) { |
| 1404 | if (knote_acquire(kn)) { |
| 1405 | knote_remove(&src->ki_note, kn); |
| 1406 | kn->kn_fop = ops; |
| 1407 | kn->kn_hook = hook; |
| 1408 | knote_insert(&dst->ki_note, kn); |
| 1409 | knote_release(kn); |
| 1410 | /* kn may be invalid now */ |
| 1411 | } |
| 1412 | } |
| 1413 | lwkt_reltoken(&kq_token); |
| 1414 | } |
| 1415 | |
| 1416 | /* |
| 1417 | * Remove all knotes referencing a specified fd |
| 1418 | */ |
| 1419 | void |
| 1420 | knote_fdclose(struct file *fp, struct filedesc *fdp, int fd) |
| 1421 | { |
| 1422 | struct knote *kn; |
| 1423 | |
| 1424 | lwkt_gettoken(&kq_token); |
| 1425 | restart: |
| 1426 | SLIST_FOREACH(kn, &fp->f_klist, kn_link) { |
| 1427 | if (kn->kn_kq->kq_fdp == fdp && kn->kn_id == fd) { |
| 1428 | if (knote_acquire(kn)) |
| 1429 | knote_detach_and_drop(kn); |
| 1430 | goto restart; |
| 1431 | } |
| 1432 | } |
| 1433 | lwkt_reltoken(&kq_token); |
| 1434 | } |
| 1435 | |
| 1436 | /* |
| 1437 | * Low level attach function. |
| 1438 | * |
| 1439 | * The knote should already be marked for processing. |
| 1440 | */ |
| 1441 | static void |
| 1442 | knote_attach(struct knote *kn) |
| 1443 | { |
| 1444 | struct klist *list; |
| 1445 | struct kqueue *kq = kn->kn_kq; |
| 1446 | |
| 1447 | if (kn->kn_fop->f_flags & FILTEROP_ISFD) { |
| 1448 | KKASSERT(kn->kn_fp); |
| 1449 | list = &kn->kn_fp->f_klist; |
| 1450 | } else { |
| 1451 | if (kq->kq_knhashmask == 0) |
| 1452 | kq->kq_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, |
| 1453 | &kq->kq_knhashmask); |
| 1454 | list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; |
| 1455 | } |
| 1456 | SLIST_INSERT_HEAD(list, kn, kn_link); |
| 1457 | TAILQ_INSERT_HEAD(&kq->kq_knlist, kn, kn_kqlink); |
| 1458 | } |
| 1459 | |
| 1460 | /* |
| 1461 | * Low level drop function. |
| 1462 | * |
| 1463 | * The knote should already be marked for processing. |
| 1464 | */ |
| 1465 | static void |
| 1466 | knote_drop(struct knote *kn) |
| 1467 | { |
| 1468 | struct kqueue *kq; |
| 1469 | struct klist *list; |
| 1470 | |
| 1471 | kq = kn->kn_kq; |
| 1472 | |
| 1473 | if (kn->kn_fop->f_flags & FILTEROP_ISFD) |
| 1474 | list = &kn->kn_fp->f_klist; |
| 1475 | else |
| 1476 | list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; |
| 1477 | |
| 1478 | SLIST_REMOVE(list, kn, knote, kn_link); |
| 1479 | TAILQ_REMOVE(&kq->kq_knlist, kn, kn_kqlink); |
| 1480 | if (kn->kn_status & KN_QUEUED) |
| 1481 | knote_dequeue(kn); |
| 1482 | if (kn->kn_fop->f_flags & FILTEROP_ISFD) { |
| 1483 | fdrop(kn->kn_fp); |
| 1484 | kn->kn_fp = NULL; |
| 1485 | } |
| 1486 | knote_free(kn); |
| 1487 | } |
| 1488 | |
| 1489 | /* |
| 1490 | * Low level enqueue function. |
| 1491 | * |
| 1492 | * The knote should already be marked for processing. |
| 1493 | */ |
| 1494 | static void |
| 1495 | knote_enqueue(struct knote *kn) |
| 1496 | { |
| 1497 | struct kqueue *kq = kn->kn_kq; |
| 1498 | |
| 1499 | KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); |
| 1500 | TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); |
| 1501 | kn->kn_status |= KN_QUEUED; |
| 1502 | ++kq->kq_count; |
| 1503 | |
| 1504 | /* |
| 1505 | * Send SIGIO on request (typically set up as a mailbox signal) |
| 1506 | */ |
| 1507 | if (kq->kq_sigio && (kq->kq_state & KQ_ASYNC) && kq->kq_count == 1) |
| 1508 | pgsigio(kq->kq_sigio, SIGIO, 0); |
| 1509 | |
| 1510 | kqueue_wakeup(kq); |
| 1511 | } |
| 1512 | |
| 1513 | /* |
| 1514 | * Low level dequeue function. |
| 1515 | * |
| 1516 | * The knote should already be marked for processing. |
| 1517 | */ |
| 1518 | static void |
| 1519 | knote_dequeue(struct knote *kn) |
| 1520 | { |
| 1521 | struct kqueue *kq = kn->kn_kq; |
| 1522 | |
| 1523 | KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); |
| 1524 | TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); |
| 1525 | kn->kn_status &= ~KN_QUEUED; |
| 1526 | kq->kq_count--; |
| 1527 | } |
| 1528 | |
| 1529 | static struct knote * |
| 1530 | knote_alloc(void) |
| 1531 | { |
| 1532 | return kmalloc(sizeof(struct knote), M_KQUEUE, M_WAITOK); |
| 1533 | } |
| 1534 | |
| 1535 | static void |
| 1536 | knote_free(struct knote *kn) |
| 1537 | { |
| 1538 | kfree(kn, M_KQUEUE); |
| 1539 | } |