The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_event.c

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    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 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD: releng/5.2/sys/kern/kern_event.c 122686 2003-11-14 18:49:01Z cognet $");
   29 
   30 #include <sys/param.h>
   31 #include <sys/systm.h>
   32 #include <sys/kernel.h>
   33 #include <sys/lock.h>
   34 #include <sys/mutex.h>
   35 #include <sys/proc.h>
   36 #include <sys/malloc.h> 
   37 #include <sys/unistd.h>
   38 #include <sys/file.h>
   39 #include <sys/filedesc.h>
   40 #include <sys/fcntl.h>
   41 #include <sys/selinfo.h>
   42 #include <sys/queue.h>
   43 #include <sys/event.h>
   44 #include <sys/eventvar.h>
   45 #include <sys/poll.h>
   46 #include <sys/protosw.h>
   47 #include <sys/socket.h>
   48 #include <sys/socketvar.h>
   49 #include <sys/stat.h>
   50 #include <sys/sysctl.h>
   51 #include <sys/sysproto.h>
   52 #include <sys/uio.h>
   53 
   54 #include <vm/uma.h>
   55 
   56 MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
   57 
   58 static int      kqueue_scan(struct file *fp, int maxevents,
   59                     struct kevent *ulistp, const struct timespec *timeout,
   60                     struct thread *td);
   61 static void     kqueue_wakeup(struct kqueue *kq);
   62 
   63 static fo_rdwr_t        kqueue_read;
   64 static fo_rdwr_t        kqueue_write;
   65 static fo_ioctl_t       kqueue_ioctl;
   66 static fo_poll_t        kqueue_poll;
   67 static fo_kqfilter_t    kqueue_kqfilter;
   68 static fo_stat_t        kqueue_stat;
   69 static fo_close_t       kqueue_close;
   70 
   71 static struct fileops kqueueops = {
   72         .fo_read = kqueue_read,
   73         .fo_write = kqueue_write,
   74         .fo_ioctl = kqueue_ioctl,
   75         .fo_poll = kqueue_poll,
   76         .fo_kqfilter = kqueue_kqfilter,
   77         .fo_stat = kqueue_stat,
   78         .fo_close = kqueue_close,
   79 };
   80 
   81 static void     knote_attach(struct knote *kn, struct filedesc *fdp);
   82 static void     knote_drop(struct knote *kn, struct thread *td);
   83 static void     knote_enqueue(struct knote *kn);
   84 static void     knote_dequeue(struct knote *kn);
   85 static void     knote_init(void);
   86 static struct   knote *knote_alloc(void);
   87 static void     knote_free(struct knote *kn);
   88 
   89 static void     filt_kqdetach(struct knote *kn);
   90 static int      filt_kqueue(struct knote *kn, long hint);
   91 static int      filt_procattach(struct knote *kn);
   92 static void     filt_procdetach(struct knote *kn);
   93 static int      filt_proc(struct knote *kn, long hint);
   94 static int      filt_fileattach(struct knote *kn);
   95 static void     filt_timerexpire(void *knx);
   96 static int      filt_timerattach(struct knote *kn);
   97 static void     filt_timerdetach(struct knote *kn);
   98 static int      filt_timer(struct knote *kn, long hint);
   99 
  100 static struct filterops file_filtops =
  101         { 1, filt_fileattach, NULL, NULL };
  102 static struct filterops kqread_filtops =
  103         { 1, NULL, filt_kqdetach, filt_kqueue };
  104 static struct filterops proc_filtops =
  105         { 0, filt_procattach, filt_procdetach, filt_proc };
  106 static struct filterops timer_filtops =
  107         { 0, filt_timerattach, filt_timerdetach, filt_timer };
  108 
  109 static uma_zone_t       knote_zone;
  110 static int              kq_ncallouts = 0;
  111 static int              kq_calloutmax = (4 * 1024);
  112 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
  113     &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
  114 
  115 #define KNOTE_ACTIVATE(kn) do {                                         \
  116         kn->kn_status |= KN_ACTIVE;                                     \
  117         if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0)           \
  118                 knote_enqueue(kn);                                      \
  119 } while(0)
  120 
  121 #define KN_HASHSIZE             64              /* XXX should be tunable */
  122 #define KN_HASH(val, mask)      (((val) ^ (val >> 8)) & (mask))
  123 
  124 static int
  125 filt_nullattach(struct knote *kn)
  126 {
  127 
  128         return (ENXIO);
  129 };
  130 
  131 struct filterops null_filtops =
  132         { 0, filt_nullattach, NULL, NULL };
  133 
  134 extern struct filterops sig_filtops;
  135 
  136 /*
  137  * Table for for all system-defined filters.
  138  */
  139 static struct filterops *sysfilt_ops[] = {
  140         &file_filtops,                  /* EVFILT_READ */
  141         &file_filtops,                  /* EVFILT_WRITE */
  142         &null_filtops,                  /* EVFILT_AIO */
  143         &file_filtops,                  /* EVFILT_VNODE */
  144         &proc_filtops,                  /* EVFILT_PROC */
  145         &sig_filtops,                   /* EVFILT_SIGNAL */
  146         &timer_filtops,                 /* EVFILT_TIMER */
  147         &file_filtops,                  /* EVFILT_NETDEV */
  148 };
  149 
  150 static int
  151 filt_fileattach(struct knote *kn)
  152 {
  153         
  154         return (fo_kqfilter(kn->kn_fp, kn));
  155 }
  156 
  157 /*ARGSUSED*/
  158 static int
  159 kqueue_kqfilter(struct file *fp, struct knote *kn)
  160 {
  161         struct kqueue *kq = kn->kn_fp->f_data;
  162 
  163         if (kn->kn_filter != EVFILT_READ)
  164                 return (1);
  165 
  166         kn->kn_fop = &kqread_filtops;
  167         SLIST_INSERT_HEAD(&kq->kq_sel.si_note, kn, kn_selnext);
  168         return (0);
  169 }
  170 
  171 static void
  172 filt_kqdetach(struct knote *kn)
  173 {
  174         struct kqueue *kq = kn->kn_fp->f_data;
  175 
  176         SLIST_REMOVE(&kq->kq_sel.si_note, kn, knote, kn_selnext);
  177 }
  178 
  179 /*ARGSUSED*/
  180 static int
  181 filt_kqueue(struct knote *kn, long hint)
  182 {
  183         struct kqueue *kq = kn->kn_fp->f_data;
  184 
  185         kn->kn_data = kq->kq_count;
  186         return (kn->kn_data > 0);
  187 }
  188 
  189 static int
  190 filt_procattach(struct knote *kn)
  191 {
  192         struct proc *p;
  193         int immediate;
  194         int error;
  195 
  196         immediate = 0;
  197         p = pfind(kn->kn_id);
  198         if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
  199                 p = zpfind(kn->kn_id);
  200                 immediate = 1;
  201         }
  202         if (p == NULL)
  203                 return (ESRCH);
  204         if ((error = p_cansee(curthread, p))) {
  205                 PROC_UNLOCK(p);
  206                 return (error);
  207         }
  208 
  209         kn->kn_ptr.p_proc = p;
  210         kn->kn_flags |= EV_CLEAR;               /* automatically set */
  211 
  212         /*
  213          * internal flag indicating registration done by kernel
  214          */
  215         if (kn->kn_flags & EV_FLAG1) {
  216                 kn->kn_data = kn->kn_sdata;             /* ppid */
  217                 kn->kn_fflags = NOTE_CHILD;
  218                 kn->kn_flags &= ~EV_FLAG1;
  219         }
  220 
  221         if (immediate == 0)
  222                 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
  223 
  224         /*
  225          * Immediately activate any exit notes if the target process is a
  226          * zombie.  This is necessary to handle the case where the target
  227          * process, e.g. a child, dies before the kevent is registered.
  228          */
  229         if (immediate && filt_proc(kn, NOTE_EXIT))
  230                 KNOTE_ACTIVATE(kn);
  231 
  232         PROC_UNLOCK(p);
  233 
  234         return (0);
  235 }
  236 
  237 /*
  238  * The knote may be attached to a different process, which may exit,
  239  * leaving nothing for the knote to be attached to.  So when the process
  240  * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
  241  * it will be deleted when read out.  However, as part of the knote deletion,
  242  * this routine is called, so a check is needed to avoid actually performing
  243  * a detach, because the original process does not exist any more.
  244  */
  245 static void
  246 filt_procdetach(struct knote *kn)
  247 {
  248         struct proc *p = kn->kn_ptr.p_proc;
  249 
  250         if (kn->kn_status & KN_DETACHED)
  251                 return;
  252 
  253         PROC_LOCK(p);
  254         SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
  255         PROC_UNLOCK(p);
  256 }
  257 
  258 static int
  259 filt_proc(struct knote *kn, long hint)
  260 {
  261         u_int event;
  262 
  263         /*
  264          * mask off extra data
  265          */
  266         event = (u_int)hint & NOTE_PCTRLMASK;
  267 
  268         /*
  269          * if the user is interested in this event, record it.
  270          */
  271         if (kn->kn_sfflags & event)
  272                 kn->kn_fflags |= event;
  273 
  274         /*
  275          * process is gone, so flag the event as finished.
  276          */
  277         if (event == NOTE_EXIT) {
  278                 kn->kn_status |= KN_DETACHED;
  279                 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 
  280                 return (1);
  281         }
  282 
  283         /*
  284          * process forked, and user wants to track the new process,
  285          * so attach a new knote to it, and immediately report an
  286          * event with the parent's pid.
  287          */
  288         if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
  289                 struct kevent kev;
  290                 int error;
  291 
  292                 /*
  293                  * register knote with new process.
  294                  */
  295                 kev.ident = hint & NOTE_PDATAMASK;      /* pid */
  296                 kev.filter = kn->kn_filter;
  297                 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
  298                 kev.fflags = kn->kn_sfflags;
  299                 kev.data = kn->kn_id;                   /* parent */
  300                 kev.udata = kn->kn_kevent.udata;        /* preserve udata */
  301                 error = kqueue_register(kn->kn_kq, &kev, NULL);
  302                 if (error)
  303                         kn->kn_fflags |= NOTE_TRACKERR;
  304         }
  305 
  306         return (kn->kn_fflags != 0);
  307 }
  308 
  309 static void
  310 filt_timerexpire(void *knx)
  311 {
  312         struct knote *kn = knx;
  313         struct callout *calloutp;
  314         struct timeval tv;
  315         int tticks;
  316 
  317         kn->kn_data++;
  318         KNOTE_ACTIVATE(kn);
  319 
  320         if ((kn->kn_flags & EV_ONESHOT) == 0) {
  321                 tv.tv_sec = kn->kn_sdata / 1000;
  322                 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
  323                 tticks = tvtohz(&tv);
  324                 calloutp = (struct callout *)kn->kn_hook;
  325                 callout_reset(calloutp, tticks, filt_timerexpire, kn);
  326         }
  327 }
  328 
  329 /*
  330  * data contains amount of time to sleep, in milliseconds
  331  */ 
  332 static int
  333 filt_timerattach(struct knote *kn)
  334 {
  335         struct callout *calloutp;
  336         struct timeval tv;
  337         int tticks;
  338 
  339         if (kq_ncallouts >= kq_calloutmax)
  340                 return (ENOMEM);
  341         kq_ncallouts++;
  342 
  343         tv.tv_sec = kn->kn_sdata / 1000;
  344         tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
  345         tticks = tvtohz(&tv);
  346 
  347         kn->kn_flags |= EV_CLEAR;               /* automatically set */
  348         MALLOC(calloutp, struct callout *, sizeof(*calloutp),
  349             M_KQUEUE, M_WAITOK);
  350         callout_init(calloutp, 0);
  351         callout_reset(calloutp, tticks, filt_timerexpire, kn);
  352         kn->kn_hook = calloutp;
  353 
  354         return (0);
  355 }
  356 
  357 static void
  358 filt_timerdetach(struct knote *kn)
  359 {
  360         struct callout *calloutp;
  361 
  362         calloutp = (struct callout *)kn->kn_hook;
  363         callout_stop(calloutp);
  364         FREE(calloutp, M_KQUEUE);
  365         kq_ncallouts--;
  366 }
  367 
  368 static int
  369 filt_timer(struct knote *kn, long hint)
  370 {
  371 
  372         return (kn->kn_data != 0);
  373 }
  374 
  375 /*
  376  * MPSAFE
  377  */
  378 int
  379 kqueue(struct thread *td, struct kqueue_args *uap)
  380 {
  381         struct filedesc *fdp;
  382         struct kqueue *kq;
  383         struct file *fp;
  384         int fd, error;
  385 
  386         mtx_lock(&Giant);
  387         fdp = td->td_proc->p_fd;
  388         error = falloc(td, &fp, &fd);
  389         if (error)
  390                 goto done2;
  391         /* An extra reference on `nfp' has been held for us by falloc(). */
  392         kq = malloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO);
  393         TAILQ_INIT(&kq->kq_head);
  394         FILE_LOCK(fp);
  395         fp->f_flag = FREAD | FWRITE;
  396         fp->f_type = DTYPE_KQUEUE;
  397         fp->f_ops = &kqueueops;
  398         TAILQ_INIT(&kq->kq_head);
  399         fp->f_data = kq;
  400         FILE_UNLOCK(fp);
  401         fdrop(fp, td);
  402         FILEDESC_LOCK(fdp);
  403         td->td_retval[0] = fd;
  404         if (fdp->fd_knlistsize < 0)
  405                 fdp->fd_knlistsize = 0;         /* this process has a kq */
  406         FILEDESC_UNLOCK(fdp);
  407         kq->kq_fdp = fdp;
  408 done2:
  409         mtx_unlock(&Giant);
  410         return (error);
  411 }
  412 
  413 #ifndef _SYS_SYSPROTO_H_
  414 struct kevent_args {
  415         int     fd;
  416         const struct kevent *changelist;
  417         int     nchanges;
  418         struct  kevent *eventlist;
  419         int     nevents;
  420         const struct timespec *timeout;
  421 };
  422 #endif
  423 /*
  424  * MPSAFE
  425  */
  426 int
  427 kevent(struct thread *td, struct kevent_args *uap)
  428 {
  429         struct kevent *kevp;
  430         struct kqueue *kq;
  431         struct file *fp;
  432         struct timespec ts;
  433         int i, n, nerrors, error;
  434 
  435         if ((error = fget(td, uap->fd, &fp)) != 0)
  436                 return (error);
  437         if (fp->f_type != DTYPE_KQUEUE) {
  438                 fdrop(fp, td);
  439                 return (EBADF);
  440         }
  441         if (uap->timeout != NULL) {
  442                 error = copyin(uap->timeout, &ts, sizeof(ts));
  443                 if (error)
  444                         goto done_nogiant;
  445                 uap->timeout = &ts;
  446         }
  447         mtx_lock(&Giant);
  448 
  449         kq = fp->f_data;
  450         nerrors = 0;
  451 
  452         while (uap->nchanges > 0) {
  453                 n = uap->nchanges > KQ_NEVENTS ? KQ_NEVENTS : uap->nchanges;
  454                 error = copyin(uap->changelist, kq->kq_kev,
  455                     n * sizeof(struct kevent));
  456                 if (error)
  457                         goto done;
  458                 for (i = 0; i < n; i++) {
  459                         kevp = &kq->kq_kev[i];
  460                         kevp->flags &= ~EV_SYSFLAGS;
  461                         error = kqueue_register(kq, kevp, td);
  462                         if (error) {
  463                                 if (uap->nevents != 0) {
  464                                         kevp->flags = EV_ERROR;
  465                                         kevp->data = error;
  466                                         (void) copyout(kevp,
  467                                             uap->eventlist,
  468                                             sizeof(*kevp));
  469                                         uap->eventlist++;
  470                                         uap->nevents--;
  471                                         nerrors++;
  472                                 } else {
  473                                         goto done;
  474                                 }
  475                         }
  476                 }
  477                 uap->nchanges -= n;
  478                 uap->changelist += n;
  479         }
  480         if (nerrors) {
  481                 td->td_retval[0] = nerrors;
  482                 error = 0;
  483                 goto done;
  484         }
  485 
  486         error = kqueue_scan(fp, uap->nevents, uap->eventlist, uap->timeout, td);
  487 done:
  488         mtx_unlock(&Giant);
  489 done_nogiant:
  490         if (fp != NULL)
  491                 fdrop(fp, td);
  492         return (error);
  493 }
  494 
  495 int
  496 kqueue_add_filteropts(int filt, struct filterops *filtops)
  497 {
  498 
  499         if (filt > 0)
  500                 panic("filt(%d) > 0", filt);
  501         if (filt + EVFILT_SYSCOUNT < 0)
  502                 panic("filt(%d) + EVFILT_SYSCOUNT(%d) == %d < 0",
  503                     filt, EVFILT_SYSCOUNT, filt + EVFILT_SYSCOUNT);
  504         if (sysfilt_ops[~filt] != &null_filtops)
  505                 panic("sysfilt_ops[~filt(%d)] != &null_filtops", filt);
  506         sysfilt_ops[~filt] = filtops;
  507         return (0);
  508 }
  509 
  510 int
  511 kqueue_del_filteropts(int filt)
  512 {
  513 
  514         if (filt > 0)
  515                 panic("filt(%d) > 0", filt);
  516         if (filt + EVFILT_SYSCOUNT < 0)
  517                 panic("filt(%d) + EVFILT_SYSCOUNT(%d) == %d < 0",
  518                     filt, EVFILT_SYSCOUNT, filt + EVFILT_SYSCOUNT);
  519         if (sysfilt_ops[~filt] == &null_filtops)
  520                 panic("sysfilt_ops[~filt(%d)] != &null_filtops", filt);
  521         sysfilt_ops[~filt] = &null_filtops;
  522         return (0);
  523 }
  524 
  525 int
  526 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td)
  527 {
  528         struct filedesc *fdp = kq->kq_fdp;
  529         struct filterops *fops;
  530         struct file *fp = NULL;
  531         struct knote *kn = NULL;
  532         int s, error = 0;
  533 
  534         if (kev->filter < 0) {
  535                 if (kev->filter + EVFILT_SYSCOUNT < 0)
  536                         return (EINVAL);
  537                 fops = sysfilt_ops[~kev->filter];       /* to 0-base index */
  538         } else {
  539                 /*
  540                  * XXX
  541                  * filter attach routine is responsible for insuring that
  542                  * the identifier can be attached to it.
  543                  */
  544                 printf("unknown filter: %d\n", kev->filter);
  545                 return (EINVAL);
  546         }
  547 
  548         FILEDESC_LOCK(fdp);
  549         if (fops->f_isfd) {
  550                 /* validate descriptor */
  551                 if ((u_int)kev->ident >= fdp->fd_nfiles ||
  552                     (fp = fdp->fd_ofiles[kev->ident]) == NULL) {
  553                         FILEDESC_UNLOCK(fdp);
  554                         return (EBADF);
  555                 }
  556                 fhold(fp);
  557 
  558                 if (kev->ident < fdp->fd_knlistsize) {
  559                         SLIST_FOREACH(kn, &fdp->fd_knlist[kev->ident], kn_link)
  560                                 if (kq == kn->kn_kq &&
  561                                     kev->filter == kn->kn_filter)
  562                                         break;
  563                 }
  564         } else {
  565                 if (fdp->fd_knhashmask != 0) {
  566                         struct klist *list;
  567                         
  568                         list = &fdp->fd_knhash[
  569                             KN_HASH((u_long)kev->ident, fdp->fd_knhashmask)];
  570                         SLIST_FOREACH(kn, list, kn_link)
  571                                 if (kev->ident == kn->kn_id &&
  572                                     kq == kn->kn_kq &&
  573                                     kev->filter == kn->kn_filter)
  574                                         break;
  575                 }
  576         }
  577         FILEDESC_UNLOCK(fdp);
  578 
  579         if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
  580                 error = ENOENT;
  581                 goto done;
  582         }
  583 
  584         /*
  585          * kn now contains the matching knote, or NULL if no match
  586          */
  587         if (kev->flags & EV_ADD) {
  588 
  589                 if (kn == NULL) {
  590                         kn = knote_alloc();
  591                         if (kn == NULL) {
  592                                 error = ENOMEM;
  593                                 goto done;
  594                         }
  595                         kn->kn_fp = fp;
  596                         kn->kn_kq = kq;
  597                         kn->kn_fop = fops;
  598 
  599                         /*
  600                          * apply reference count to knote structure, and
  601                          * do not release it at the end of this routine.
  602                          */
  603                         fp = NULL;
  604 
  605                         kn->kn_sfflags = kev->fflags;
  606                         kn->kn_sdata = kev->data;
  607                         kev->fflags = 0;
  608                         kev->data = 0;
  609                         kn->kn_kevent = *kev;
  610 
  611                         knote_attach(kn, fdp);
  612                         if ((error = fops->f_attach(kn)) != 0) {
  613                                 knote_drop(kn, td);
  614                                 goto done;
  615                         }
  616                 } else {
  617                         /*
  618                          * The user may change some filter values after the
  619                          * initial EV_ADD, but doing so will not reset any 
  620                          * filter which has already been triggered.
  621                          */
  622                         kn->kn_sfflags = kev->fflags;
  623                         kn->kn_sdata = kev->data;
  624                         kn->kn_kevent.udata = kev->udata;
  625                 }
  626 
  627                 s = splhigh();
  628                 if (kn->kn_fop->f_event(kn, 0))
  629                         KNOTE_ACTIVATE(kn);
  630                 splx(s);
  631 
  632         } else if (kev->flags & EV_DELETE) {
  633                 kn->kn_fop->f_detach(kn);
  634                 knote_drop(kn, td);
  635                 goto done;
  636         }
  637 
  638         if ((kev->flags & EV_DISABLE) &&
  639             ((kn->kn_status & KN_DISABLED) == 0)) {
  640                 s = splhigh();
  641                 kn->kn_status |= KN_DISABLED;
  642                 splx(s);
  643         }
  644 
  645         if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
  646                 s = splhigh();
  647                 kn->kn_status &= ~KN_DISABLED;
  648                 if ((kn->kn_status & KN_ACTIVE) &&
  649                     ((kn->kn_status & KN_QUEUED) == 0))
  650                         knote_enqueue(kn);
  651                 splx(s);
  652         }
  653 
  654 done:
  655         if (fp != NULL)
  656                 fdrop(fp, td);
  657         return (error);
  658 }
  659 
  660 static int
  661 kqueue_scan(struct file *fp, int maxevents, struct kevent *ulistp,
  662         const struct timespec *tsp, struct thread *td)
  663 {
  664         struct kqueue *kq;
  665         struct kevent *kevp;
  666         struct timeval atv, rtv, ttv;
  667         struct knote *kn, marker;
  668         int s, count, timeout, nkev = 0, error = 0;
  669 
  670         FILE_LOCK_ASSERT(fp, MA_NOTOWNED);
  671 
  672         kq = fp->f_data;
  673         count = maxevents;
  674         if (count == 0)
  675                 goto done;
  676 
  677         if (tsp != NULL) {
  678                 TIMESPEC_TO_TIMEVAL(&atv, tsp);
  679                 if (itimerfix(&atv)) {
  680                         error = EINVAL;
  681                         goto done;
  682                 }
  683                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
  684                         timeout = -1;
  685                 else 
  686                         timeout = atv.tv_sec > 24 * 60 * 60 ?
  687                             24 * 60 * 60 * hz : tvtohz(&atv);
  688                 getmicrouptime(&rtv);
  689                 timevaladd(&atv, &rtv);
  690         } else {
  691                 atv.tv_sec = 0;
  692                 atv.tv_usec = 0;
  693                 timeout = 0;
  694         }
  695         goto start;
  696 
  697 retry:
  698         if (atv.tv_sec || atv.tv_usec) {
  699                 getmicrouptime(&rtv);
  700                 if (timevalcmp(&rtv, &atv, >=))
  701                         goto done;
  702                 ttv = atv;
  703                 timevalsub(&ttv, &rtv);
  704                 timeout = ttv.tv_sec > 24 * 60 * 60 ?
  705                         24 * 60 * 60 * hz : tvtohz(&ttv);
  706         }
  707 
  708 start:
  709         kevp = kq->kq_kev;
  710         s = splhigh();
  711         if (kq->kq_count == 0) {
  712                 if (timeout < 0) { 
  713                         error = EWOULDBLOCK;
  714                 } else {
  715                         kq->kq_state |= KQ_SLEEP;
  716                         error = tsleep(kq, PSOCK | PCATCH, "kqread", timeout);
  717                 }
  718                 splx(s);
  719                 if (error == 0)
  720                         goto retry;
  721                 /* don't restart after signals... */
  722                 if (error == ERESTART)
  723                         error = EINTR;
  724                 else if (error == EWOULDBLOCK)
  725                         error = 0;
  726                 goto done;
  727         }
  728 
  729         TAILQ_INSERT_TAIL(&kq->kq_head, &marker, kn_tqe); 
  730         while (count) {
  731                 kn = TAILQ_FIRST(&kq->kq_head);
  732                 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 
  733                 if (kn == &marker) {
  734                         splx(s);
  735                         if (count == maxevents)
  736                                 goto retry;
  737                         goto done;
  738                 }
  739                 if (kn->kn_status & KN_DISABLED) {
  740                         kn->kn_status &= ~KN_QUEUED;
  741                         kq->kq_count--;
  742                         continue;
  743                 }
  744                 if ((kn->kn_flags & EV_ONESHOT) == 0 &&
  745                     kn->kn_fop->f_event(kn, 0) == 0) {
  746                         kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
  747                         kq->kq_count--;
  748                         continue;
  749                 }
  750                 *kevp = kn->kn_kevent;
  751                 kevp++;
  752                 nkev++;
  753                 if (kn->kn_flags & EV_ONESHOT) {
  754                         kn->kn_status &= ~KN_QUEUED;
  755                         kq->kq_count--;
  756                         splx(s);
  757                         kn->kn_fop->f_detach(kn);
  758                         knote_drop(kn, td);
  759                         s = splhigh();
  760                 } else if (kn->kn_flags & EV_CLEAR) {
  761                         kn->kn_data = 0;
  762                         kn->kn_fflags = 0;
  763                         kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
  764                         kq->kq_count--;
  765                 } else {
  766                         TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 
  767                 }
  768                 count--;
  769                 if (nkev == KQ_NEVENTS) {
  770                         splx(s);
  771                         error = copyout(&kq->kq_kev, ulistp,
  772                             sizeof(struct kevent) * nkev);
  773                         ulistp += nkev;
  774                         nkev = 0;
  775                         kevp = kq->kq_kev;
  776                         s = splhigh();
  777                         if (error)
  778                                 break;
  779                 }
  780         }
  781         TAILQ_REMOVE(&kq->kq_head, &marker, kn_tqe); 
  782         splx(s);
  783 done:
  784         if (nkev != 0)
  785                 error = copyout(&kq->kq_kev, ulistp,
  786                     sizeof(struct kevent) * nkev);
  787         td->td_retval[0] = maxevents - count;
  788         return (error);
  789 }
  790 
  791 /*
  792  * XXX
  793  * This could be expanded to call kqueue_scan, if desired.
  794  */
  795 /*ARGSUSED*/
  796 static int
  797 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
  798         int flags, struct thread *td)
  799 {
  800         return (ENXIO);
  801 }
  802 
  803 /*ARGSUSED*/
  804 static int
  805 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
  806          int flags, struct thread *td)
  807 {
  808         return (ENXIO);
  809 }
  810 
  811 /*ARGSUSED*/
  812 static int
  813 kqueue_ioctl(struct file *fp, u_long com, void *data,
  814         struct ucred *active_cred, struct thread *td)
  815 {
  816         return (ENOTTY);
  817 }
  818 
  819 /*ARGSUSED*/
  820 static int
  821 kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
  822         struct thread *td)
  823 {
  824         struct kqueue *kq;
  825         int revents = 0;
  826         int s = splnet();
  827 
  828         kq = fp->f_data;
  829         if (events & (POLLIN | POLLRDNORM)) {
  830                 if (kq->kq_count) {
  831                         revents |= events & (POLLIN | POLLRDNORM);
  832                 } else {
  833                         selrecord(td, &kq->kq_sel);
  834                         kq->kq_state |= KQ_SEL;
  835                 }
  836         }
  837         splx(s);
  838         return (revents);
  839 }
  840 
  841 /*ARGSUSED*/
  842 static int
  843 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
  844         struct thread *td)
  845 {
  846         struct kqueue *kq;
  847 
  848         kq = fp->f_data;
  849         bzero((void *)st, sizeof(*st));
  850         st->st_size = kq->kq_count;
  851         st->st_blksize = sizeof(struct kevent);
  852         st->st_mode = S_IFIFO;
  853         return (0);
  854 }
  855 
  856 /*ARGSUSED*/
  857 static int
  858 kqueue_close(struct file *fp, struct thread *td)
  859 {
  860         struct kqueue *kq = fp->f_data;
  861         struct filedesc *fdp = kq->kq_fdp;
  862         struct knote **knp, *kn, *kn0;
  863         int i;
  864 
  865         FILEDESC_LOCK(fdp);
  866         for (i = 0; i < fdp->fd_knlistsize; i++) {
  867                 knp = &SLIST_FIRST(&fdp->fd_knlist[i]);
  868                 kn = *knp;
  869                 while (kn != NULL) {
  870                         kn0 = SLIST_NEXT(kn, kn_link);
  871                         if (kq == kn->kn_kq) {
  872                                 kn->kn_fop->f_detach(kn);
  873                                 *knp = kn0;
  874                                 FILE_LOCK(kn->kn_fp);
  875                                 FILEDESC_UNLOCK(fdp);
  876                                 fdrop_locked(kn->kn_fp, td);
  877                                 knote_free(kn);
  878                                 FILEDESC_LOCK(fdp);
  879                         } else {
  880                                 knp = &SLIST_NEXT(kn, kn_link);
  881                         }
  882                         kn = kn0;
  883                 }
  884         }
  885         if (fdp->fd_knhashmask != 0) {
  886                 for (i = 0; i < fdp->fd_knhashmask + 1; i++) {
  887                         knp = &SLIST_FIRST(&fdp->fd_knhash[i]);
  888                         kn = *knp;
  889                         while (kn != NULL) {
  890                                 kn0 = SLIST_NEXT(kn, kn_link);
  891                                 if (kq == kn->kn_kq) {
  892                                         kn->kn_fop->f_detach(kn);
  893                                         *knp = kn0;
  894                 /* XXX non-fd release of kn->kn_ptr */
  895                                         FILEDESC_UNLOCK(fdp);
  896                                         knote_free(kn);
  897                                         FILEDESC_LOCK(fdp);
  898                                 } else {
  899                                         knp = &SLIST_NEXT(kn, kn_link);
  900                                 }
  901                                 kn = kn0;
  902                         }
  903                 }
  904         }
  905         FILEDESC_UNLOCK(fdp);
  906         free(kq, M_KQUEUE);
  907         fp->f_data = NULL;
  908 
  909         return (0);
  910 }
  911 
  912 static void
  913 kqueue_wakeup(struct kqueue *kq)
  914 {
  915 
  916         if (kq->kq_state & KQ_SLEEP) {
  917                 kq->kq_state &= ~KQ_SLEEP;
  918                 wakeup(kq);
  919         }
  920         if (kq->kq_state & KQ_SEL) {
  921                 kq->kq_state &= ~KQ_SEL;
  922                 selwakeuppri(&kq->kq_sel, PSOCK);
  923         }
  924         KNOTE(&kq->kq_sel.si_note, 0);
  925 }
  926 
  927 /*
  928  * walk down a list of knotes, activating them if their event has triggered.
  929  */
  930 void
  931 knote(struct klist *list, long hint)
  932 {
  933         struct knote *kn;
  934 
  935         SLIST_FOREACH(kn, list, kn_selnext)
  936                 if (kn->kn_fop->f_event(kn, hint))
  937                         KNOTE_ACTIVATE(kn);
  938 }
  939 
  940 /*
  941  * remove all knotes from a specified klist
  942  */
  943 void
  944 knote_remove(struct thread *td, struct klist *list)
  945 {
  946         struct knote *kn;
  947 
  948         while ((kn = SLIST_FIRST(list)) != NULL) {
  949                 kn->kn_fop->f_detach(kn);
  950                 knote_drop(kn, td);
  951         }
  952 }
  953 
  954 /*
  955  * remove all knotes referencing a specified fd
  956  */
  957 void
  958 knote_fdclose(struct thread *td, int fd)
  959 {
  960         struct filedesc *fdp = td->td_proc->p_fd;
  961         struct klist *list;
  962 
  963         FILEDESC_LOCK(fdp);
  964         list = &fdp->fd_knlist[fd];
  965         FILEDESC_UNLOCK(fdp);
  966         knote_remove(td, list);
  967 }
  968 
  969 static void
  970 knote_attach(struct knote *kn, struct filedesc *fdp)
  971 {
  972         struct klist *list, *tmp_knhash;
  973         u_long tmp_knhashmask;
  974         int size;
  975 
  976         FILEDESC_LOCK(fdp);
  977 
  978         if (! kn->kn_fop->f_isfd) {
  979                 if (fdp->fd_knhashmask == 0) {
  980                         FILEDESC_UNLOCK(fdp);
  981                         tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
  982                             &tmp_knhashmask);
  983                         FILEDESC_LOCK(fdp);
  984                         if (fdp->fd_knhashmask == 0) {
  985                                 fdp->fd_knhash = tmp_knhash;
  986                                 fdp->fd_knhashmask = tmp_knhashmask;
  987                         } else {
  988                                 free(tmp_knhash, M_KQUEUE);
  989                         }
  990                 }
  991                 list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
  992                 goto done;
  993         }
  994 
  995         if (fdp->fd_knlistsize <= kn->kn_id) {
  996                 size = fdp->fd_knlistsize;
  997                 while (size <= kn->kn_id)
  998                         size += KQEXTENT;
  999                 FILEDESC_UNLOCK(fdp);
 1000                 MALLOC(list, struct klist *,
 1001                     size * sizeof(struct klist *), M_KQUEUE, M_WAITOK);
 1002                 FILEDESC_LOCK(fdp);
 1003                 if (fdp->fd_knlistsize > kn->kn_id) {
 1004                         FREE(list, M_KQUEUE);
 1005                         goto bigenough;
 1006                 }
 1007                 if (fdp->fd_knlist != NULL) {
 1008                         bcopy(fdp->fd_knlist, list,
 1009                             fdp->fd_knlistsize * sizeof(struct klist *));
 1010                         FREE(fdp->fd_knlist, M_KQUEUE);
 1011                 }
 1012                 bzero((caddr_t)list +
 1013                     fdp->fd_knlistsize * sizeof(struct klist *),
 1014                     (size - fdp->fd_knlistsize) * sizeof(struct klist *));
 1015                 fdp->fd_knlistsize = size;
 1016                 fdp->fd_knlist = list;
 1017         }
 1018 bigenough:
 1019         list = &fdp->fd_knlist[kn->kn_id];
 1020 done:
 1021         FILEDESC_UNLOCK(fdp);
 1022         SLIST_INSERT_HEAD(list, kn, kn_link);
 1023         kn->kn_status = 0;
 1024 }
 1025 
 1026 /*
 1027  * should be called at spl == 0, since we don't want to hold spl
 1028  * while calling fdrop and free.
 1029  */
 1030 static void
 1031 knote_drop(struct knote *kn, struct thread *td)
 1032 {
 1033         struct filedesc *fdp = td->td_proc->p_fd;
 1034         struct klist *list;
 1035 
 1036         FILEDESC_LOCK(fdp);
 1037         if (kn->kn_fop->f_isfd)
 1038                 list = &fdp->fd_knlist[kn->kn_id];
 1039         else
 1040                 list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
 1041         if (kn->kn_fop->f_isfd)
 1042                 FILE_LOCK(kn->kn_fp);
 1043         FILEDESC_UNLOCK(fdp);
 1044 
 1045         SLIST_REMOVE(list, kn, knote, kn_link);
 1046         if (kn->kn_status & KN_QUEUED)
 1047                 knote_dequeue(kn);
 1048         if (kn->kn_fop->f_isfd)
 1049                 fdrop_locked(kn->kn_fp, td);
 1050         knote_free(kn);
 1051 }
 1052 
 1053 
 1054 static void
 1055 knote_enqueue(struct knote *kn)
 1056 {
 1057         struct kqueue *kq = kn->kn_kq;
 1058         int s = splhigh();
 1059 
 1060         KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
 1061 
 1062         TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 
 1063         kn->kn_status |= KN_QUEUED;
 1064         kq->kq_count++;
 1065         splx(s);
 1066         kqueue_wakeup(kq);
 1067 }
 1068 
 1069 static void
 1070 knote_dequeue(struct knote *kn)
 1071 {
 1072         struct kqueue *kq = kn->kn_kq;
 1073         int s = splhigh();
 1074 
 1075         KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
 1076 
 1077         TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 
 1078         kn->kn_status &= ~KN_QUEUED;
 1079         kq->kq_count--;
 1080         splx(s);
 1081 }
 1082 
 1083 static void
 1084 knote_init(void)
 1085 {
 1086         knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
 1087             NULL, NULL, UMA_ALIGN_PTR, 0);
 1088 
 1089 }
 1090 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL)
 1091 
 1092 static struct knote *
 1093 knote_alloc(void)
 1094 {
 1095         return ((struct knote *)uma_zalloc(knote_zone, M_WAITOK));
 1096 }
 1097 
 1098 static void
 1099 knote_free(struct knote *kn)
 1100 {
 1101         uma_zfree(knote_zone, kn);
 1102 }

Cache object: ab1bead06771429a761f895d4dbc2827


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