common/isc/eventlib.c

/*
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1995-1999 by Internet Software Consortium
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/* eventlib.c - implement glue for the eventlib
 * vix 09sep95 [initial]
 */

#if !defined(LINT) && !defined(CODECENTER)
static const char rcsid[] = "$Id: eventlib.c,v 1.10 2006/03/09 23:57:56 marka Exp $";
#endif

#include "port_before.h"
#include "fd_setsize.h"

#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#ifdef  SOLARIS2
#include <limits.h>
#endif  /* SOLARIS2 */

#include <errno.h>
#include <signal.h>
#include <stdarg.h>
#include <stdlib.h>
#include <unistd.h>

#include <isc/eventlib.h>
#include <isc/assertions.h>
#include "eventlib_p.h"

#include "port_after.h"

int      __evOptMonoTime;

#ifdef USE_POLL
#define pselect Pselect
#endif /* USE_POLL */

/* Forward. */

#if defined(NEED_PSELECT) || defined(USE_POLL)
static int      pselect(int, void *, void *, void *,
                struct timespec *,
                const sigset_t *);
#endif

int    __evOptMonoTime;

/* Public. */

int
evCreate(evContext *opaqueCtx) {
    evContext_p *ctx;

    /* Make sure the memory heap is initialized. */
    if (meminit(0, 0) < 0 && errno != EEXIST)
        return (-1);

    OKNEW(ctx);

    /* Global. */
    ctx->cur = NULL;

    /* Debugging. */
    ctx->debug = 0;
    ctx->output = NULL;

    /* Connections. */
    ctx->conns = NULL;
    INIT_LIST(ctx->accepts);

    /* Files. */
    ctx->files = NULL;
#ifdef USE_POLL
        ctx->pollfds = NULL;
    ctx->maxnfds = 0;
    ctx->firstfd = 0;
    emulMaskInit(ctx, rdLast, EV_READ, 1);
    emulMaskInit(ctx, rdNext, EV_READ, 0);
    emulMaskInit(ctx, wrLast, EV_WRITE, 1);
    emulMaskInit(ctx, wrNext, EV_WRITE, 0);
    emulMaskInit(ctx, exLast, EV_EXCEPT, 1);
    emulMaskInit(ctx, exNext, EV_EXCEPT, 0);
    emulMaskInit(ctx, nonblockBefore, EV_WASNONBLOCKING, 0);
#endif /* USE_POLL */
    FD_ZERO(&ctx->rdNext);
    FD_ZERO(&ctx->wrNext);
    FD_ZERO(&ctx->exNext);
    FD_ZERO(&ctx->nonblockBefore);
    ctx->fdMax = -1;
    ctx->fdNext = NULL;
    ctx->fdCount = 0;   /*%< Invalidate {rd,wr,ex}Last. */
#ifndef USE_POLL
    ctx->highestFD = FD_SETSIZE - 1;
    memset(ctx->fdTable, 0, sizeof ctx->fdTable);
#else
    ctx->highestFD = INT_MAX / sizeof(struct pollfd);
    ctx->fdTable = NULL;
#endif /* USE_POLL */
#ifdef EVENTLIB_TIME_CHECKS
    ctx->lastFdCount = 0;
#endif

    /* Streams. */
    ctx->streams = NULL;
    ctx->strDone = NULL;
    ctx->strLast = NULL;

    /* Timers. */
    ctx->lastEventTime = evNowTime();
#ifdef EVENTLIB_TIME_CHECKS
    ctx->lastSelectTime = ctx->lastEventTime;
#endif
    ctx->timers = evCreateTimers(ctx);
    if (ctx->timers == NULL)
        return (-1);

    /* Waits. */
    ctx->waitLists = NULL;
    ctx->waitDone.first = ctx->waitDone.last = NULL;
    ctx->waitDone.prev = ctx->waitDone.next = NULL;

    opaqueCtx->opaque = ctx;
    return (0);
}

void
evSetDebug(evContext opaqueCtx, int level, FILE *output) {
    evContext_p *ctx = opaqueCtx.opaque;

    ctx->debug = level;
    ctx->output = output;
}

int
evDestroy(evContext opaqueCtx) {
    evContext_p *ctx = opaqueCtx.opaque;
    int revs = 424242;  /*%< Doug Adams. */
    evWaitList *this_wl, *next_wl;
    evWait *this_wait, *next_wait;

    /* Connections. */
    while (revs-- > 0 && ctx->conns != NULL) {
        evConnID id;

        id.opaque = ctx->conns;
        (void) evCancelConn(opaqueCtx, id);
    }
    INSIST(revs >= 0);

    /* Streams. */
    while (revs-- > 0 && ctx->streams != NULL) {
        evStreamID id;

        id.opaque = ctx->streams;
        (void) evCancelRW(opaqueCtx, id);
    }

    /* Files. */
    while (revs-- > 0 && ctx->files != NULL) {
        evFileID id;

        id.opaque = ctx->files;
        (void) evDeselectFD(opaqueCtx, id);
    }
    INSIST(revs >= 0);

    /* Timers. */
    evDestroyTimers(ctx);

    /* Waits. */
    for (this_wl = ctx->waitLists;
         revs-- > 0 && this_wl != NULL;
         this_wl = next_wl) {
        next_wl = this_wl->next;
        for (this_wait = this_wl->first;
             revs-- > 0 && this_wait != NULL;
             this_wait = next_wait) {
            next_wait = this_wait->next;
            FREE(this_wait);
        }
        FREE(this_wl);
    }
    for (this_wait = ctx->waitDone.first;
         revs-- > 0 && this_wait != NULL;
         this_wait = next_wait) {
        next_wait = this_wait->next;
        FREE(this_wait);
    }

    FREE(ctx);
    return (0);
}

int
evGetNext(evContext opaqueCtx, evEvent *opaqueEv, int options) {
    evContext_p *ctx = opaqueCtx.opaque;
    struct timespec nextTime;
    evTimer *nextTimer;
    evEvent_p *new;
    int x, pselect_errno, timerPast;
#ifdef EVENTLIB_TIME_CHECKS
    struct timespec interval;
#endif

    /* Ensure that exactly one of EV_POLL or EV_WAIT was specified. */
    x = ((options & EV_POLL) != 0) + ((options & EV_WAIT) != 0);
    if (x != 1)
        EV_ERR(EINVAL);

    /* Get the time of day.  We'll do this again after select() blocks. */
    ctx->lastEventTime = evNowTime();

 again:
    /* Finished accept()'s do not require a select(). */
    if (!EMPTY(ctx->accepts)) {
        OKNEW(new);
        new->type = Accept;
        new->u.accept.this = HEAD(ctx->accepts);
        UNLINK(ctx->accepts, HEAD(ctx->accepts), link);
        opaqueEv->opaque = new;
        return (0);
    }

    /* Stream IO does not require a select(). */
    if (ctx->strDone != NULL) {
        OKNEW(new);
        new->type = Stream;
        new->u.stream.this = ctx->strDone;
        ctx->strDone = ctx->strDone->nextDone;
        if (ctx->strDone == NULL)
            ctx->strLast = NULL;
        opaqueEv->opaque = new;
        return (0);
    }

    /* Waits do not require a select(). */
    if (ctx->waitDone.first != NULL) {
        OKNEW(new);
        new->type = Wait;
        new->u.wait.this = ctx->waitDone.first;
        ctx->waitDone.first = ctx->waitDone.first->next;
        if (ctx->waitDone.first == NULL)
            ctx->waitDone.last = NULL;
        opaqueEv->opaque = new;
        return (0);
    }

    /* Get the status and content of the next timer. */
    if ((nextTimer = heap_element(ctx->timers, 1)) != NULL) {
        nextTime = nextTimer->due;
        timerPast = (evCmpTime(nextTime, ctx->lastEventTime) <= 0);
    } else
        timerPast = 0;  /*%< Make gcc happy. */
    evPrintf(ctx, 9, "evGetNext: fdCount %d\n", ctx->fdCount);
    if (ctx->fdCount == 0) {
        static const struct timespec NoTime = {0, 0L};
        enum { JustPoll, Block, Timer } m;
        struct timespec t, *tp;

        /* Are there any events at all? */
        if ((options & EV_WAIT) != 0 && !nextTimer && ctx->fdMax == -1)
            EV_ERR(ENOENT);

        /* Figure out what select()'s timeout parameter should be. */
        if ((options & EV_POLL) != 0) {
            m = JustPoll;
            t = NoTime;
            tp = &t;
        } else if (nextTimer == NULL) {
            m = Block;
            /* ``t'' unused. */
            tp = NULL;
        } else if (timerPast) {
            m = JustPoll;
            t = NoTime;
            tp = &t;
        } else {
            m = Timer;
            /* ``t'' filled in later. */
            tp = &t;
        }
#ifdef EVENTLIB_TIME_CHECKS
        if (ctx->debug > 0) {
            interval = evSubTime(ctx->lastEventTime,
                         ctx->lastSelectTime);
            if (interval.tv_sec > 0 || interval.tv_nsec > 0)
                evPrintf(ctx, 1,
                   "time between pselect() %u.%09u count %d\n",
                     interval.tv_sec, interval.tv_nsec,
                     ctx->lastFdCount);
        }
#endif
        do {
#ifndef USE_POLL
             /* XXX need to copy only the bits we are using. */
             ctx->rdLast = ctx->rdNext;
             ctx->wrLast = ctx->wrNext;
             ctx->exLast = ctx->exNext;
#else
            /*
             * The pollfd structure uses separate fields for
             * the input and output events (corresponding to
             * the ??Next and ??Last fd sets), so there's no
             * need to copy one to the other.
             */
#endif /* USE_POLL */
            if (m == Timer) {
                INSIST(tp == &t);
                t = evSubTime(nextTime, ctx->lastEventTime);
            }

            /* XXX should predict system's earliness and adjust. */
            x = pselect(ctx->fdMax+1,
                    &ctx->rdLast, &ctx->wrLast, &ctx->exLast,
                    tp, NULL);
            pselect_errno = errno;

#ifndef USE_POLL
            evPrintf(ctx, 4, "select() returns %d (err: %s)\n",
                 x, (x == -1) ? strerror(errno) : "none");
#else
            evPrintf(ctx, 4, "poll() returns %d (err: %s)\n",
                x, (x == -1) ? strerror(errno) : "none");
#endif /* USE_POLL */
            /* Anything but a poll can change the time. */
            if (m != JustPoll)
                ctx->lastEventTime = evNowTime();

            /* Select() likes to finish about 10ms early. */
        } while (x == 0 && m == Timer &&
             evCmpTime(ctx->lastEventTime, nextTime) < 0);
#ifdef EVENTLIB_TIME_CHECKS
        ctx->lastSelectTime = ctx->lastEventTime;
#endif
        if (x < 0) {
            if (pselect_errno == EINTR) {
                if ((options & EV_NULL) != 0)
                    goto again;
                OKNEW(new);
                new->type = Null;
                /* No data. */
                opaqueEv->opaque = new;
                return (0);
            }
            if (pselect_errno == EBADF) {
                for (x = 0; x <= ctx->fdMax; x++) {
                    struct stat sb;

                    if (FD_ISSET(x, &ctx->rdNext) == 0 &&
                        FD_ISSET(x, &ctx->wrNext) == 0 &&
                        FD_ISSET(x, &ctx->exNext) == 0)
                        continue;
                    if (fstat(x, &sb) == -1 &&
                        errno == EBADF)
                        evPrintf(ctx, 1, "EBADF: %d\n",
                             x);
                }
                abort();
            }
            EV_ERR(pselect_errno);
        }
        if (x == 0 && (nextTimer == NULL || !timerPast) &&
            (options & EV_POLL))
            EV_ERR(EWOULDBLOCK);
        ctx->fdCount = x;
#ifdef EVENTLIB_TIME_CHECKS
        ctx->lastFdCount = x;
#endif
    }
    INSIST(nextTimer || ctx->fdCount);

    /* Timers go first since we'd like them to be accurate. */
    if (nextTimer && !timerPast) {
        /* Has anything happened since we blocked? */
        timerPast = (evCmpTime(nextTime, ctx->lastEventTime) <= 0);
    }
    if (nextTimer && timerPast) {
        OKNEW(new);
        new->type = Timer;
        new->u.timer.this = nextTimer;
        opaqueEv->opaque = new;
        return (0);
    }

    /* No timers, so there should be a ready file descriptor. */
    x = 0;
    while (ctx->fdCount > 0) {
        evFile *fid;
        int fd, eventmask;

        if (ctx->fdNext == NULL) {
            if (++x == 2) {
                /*
                 * Hitting the end twice means that the last
                 * select() found some FD's which have since
                 * been deselected.
                 *
                 * On some systems, the count returned by
                 * selects is the total number of bits in
                 * all masks that are set, and on others it's
                 * the number of fd's that have some bit set,
                 * and on others, it's just broken.  We
                 * always assume that it's the number of
                 * bits set in all masks, because that's what
                 * the man page says it should do, and
                 * the worst that can happen is we do an
                 * extra select().
                 */
                ctx->fdCount = 0;
                break;
            }
            ctx->fdNext = ctx->files;
        }
        fid = ctx->fdNext;
        ctx->fdNext = fid->next;

        fd = fid->fd;
        eventmask = 0;
        if (FD_ISSET(fd, &ctx->rdLast))
            eventmask |= EV_READ;
        if (FD_ISSET(fd, &ctx->wrLast))
            eventmask |= EV_WRITE;
        if (FD_ISSET(fd, &ctx->exLast))
            eventmask |= EV_EXCEPT;
        eventmask &= fid->eventmask;
        if (eventmask != 0) {
            if ((eventmask & EV_READ) != 0) {
                FD_CLR(fd, &ctx->rdLast);
                ctx->fdCount--;
            }
            if ((eventmask & EV_WRITE) != 0) {
                FD_CLR(fd, &ctx->wrLast);
                ctx->fdCount--;
            }
            if ((eventmask & EV_EXCEPT) != 0) {
                FD_CLR(fd, &ctx->exLast);
                ctx->fdCount--;
            }
            OKNEW(new);
            new->type = File;
            new->u.file.this = fid;
            new->u.file.eventmask = eventmask;
            opaqueEv->opaque = new;
            return (0);
        }
    }
    if (ctx->fdCount < 0) {
        /*
         * select()'s count is off on a number of systems, and
         * can result in fdCount < 0.
         */
        evPrintf(ctx, 4, "fdCount < 0 (%d)\n", ctx->fdCount);
        ctx->fdCount = 0;
    }

    /* We get here if the caller deselect()'s an FD. Gag me with a goto. */
    goto again;
}

int
evDispatch(evContext opaqueCtx, evEvent opaqueEv) {
    evContext_p *ctx = opaqueCtx.opaque;
    evEvent_p *ev = opaqueEv.opaque;
#ifdef EVENTLIB_TIME_CHECKS
    void *func;
    struct timespec start_time;
    struct timespec interval;
#endif

#ifdef EVENTLIB_TIME_CHECKS
    if (ctx->debug > 0)
        start_time = evNowTime();
#endif
    ctx->cur = ev;
    switch (ev->type) {
        case Accept: {
        evAccept *this = ev->u.accept.this;

        evPrintf(ctx, 5,
            "Dispatch.Accept: fd %d -> %d, func %p, uap %p\n",
             this->conn->fd, this->fd,
             this->conn->func, this->conn->uap);
        errno = this->ioErrno;
        (this->conn->func)(opaqueCtx, this->conn->uap, this->fd,
                   &this->la, this->lalen,
                   &this->ra, this->ralen);
#ifdef EVENTLIB_TIME_CHECKS
        func = this->conn->func;
#endif
        break;
        }
        case File: {
        evFile *this = ev->u.file.this;
        int eventmask = ev->u.file.eventmask;

        evPrintf(ctx, 5,
            "Dispatch.File: fd %d, mask 0x%x, func %p, uap %p\n",
             this->fd, this->eventmask, this->func, this->uap);
        (this->func)(opaqueCtx, this->uap, this->fd, eventmask);
#ifdef EVENTLIB_TIME_CHECKS
        func = this->func;
#endif
        break;
        }
        case Stream: {
        evStream *this = ev->u.stream.this;

        evPrintf(ctx, 5,
             "Dispatch.Stream: fd %d, func %p, uap %p\n",
             this->fd, this->func, this->uap);
        errno = this->ioErrno;
        (this->func)(opaqueCtx, this->uap, this->fd, this->ioDone);
#ifdef EVENTLIB_TIME_CHECKS
        func = this->func;
#endif
        break;
        }
        case Timer: {
        evTimer *this = ev->u.timer.this;

        evPrintf(ctx, 5, "Dispatch.Timer: func %p, uap %p\n",
             this->func, this->uap);
        (this->func)(opaqueCtx, this->uap, this->due, this->inter);
#ifdef EVENTLIB_TIME_CHECKS
        func = this->func;
#endif
        break;
        }
        case Wait: {
        evWait *this = ev->u.wait.this;

        evPrintf(ctx, 5,
             "Dispatch.Wait: tag %p, func %p, uap %p\n",
             this->tag, this->func, this->uap);
        (this->func)(opaqueCtx, this->uap, this->tag);
#ifdef EVENTLIB_TIME_CHECKS
        func = this->func;
#endif
        break;
        }
        case Null: {
        /* No work. */
#ifdef EVENTLIB_TIME_CHECKS
        func = NULL;
#endif
        break;
        }
        default: {
        abort();
        }
    }
#ifdef EVENTLIB_TIME_CHECKS
    if (ctx->debug > 0) {
        interval = evSubTime(evNowTime(), start_time);
        /*
         * Complain if it took longer than 50 milliseconds.
         *
         * We call getuid() to make an easy to find mark in a kernel
         * trace.
         */
        if (interval.tv_sec > 0 || interval.tv_nsec > 50000000)
            evPrintf(ctx, 1,
             "dispatch interval %u.%09u uid %d type %d func %p\n",
                 interval.tv_sec, interval.tv_nsec,
                 getuid(), ev->type, func);
    }
#endif
    ctx->cur = NULL;
    evDrop(opaqueCtx, opaqueEv);
    return (0);
}

void
evDrop(evContext opaqueCtx, evEvent opaqueEv) {
    evContext_p *ctx = opaqueCtx.opaque;
    evEvent_p *ev = opaqueEv.opaque;

    switch (ev->type) {
        case Accept: {
        FREE(ev->u.accept.this);
        break;
        }
        case File: {
        /* No work. */
        break;
        }
        case Stream: {
        evStreamID id;

        id.opaque = ev->u.stream.this;
        (void) evCancelRW(opaqueCtx, id);
        break;
        }
        case Timer: {
        evTimer *this = ev->u.timer.this;
        evTimerID opaque;

        /* Check to see whether the user func cleared the timer. */
        if (heap_element(ctx->timers, this->index) != this) {
            evPrintf(ctx, 5, "Dispatch.Timer: timer rm'd?\n");
            break;
        }
        /*
         * Timer is still there.  Delete it if it has expired,
         * otherwise set it according to its next interval.
         */
        if (this->inter.tv_sec == (time_t)0 &&
            this->inter.tv_nsec == 0L) {
            opaque.opaque = this;
            (void) evClearTimer(opaqueCtx, opaque);
        } else {
            opaque.opaque = this;
            (void) evResetTimer(opaqueCtx, opaque, this->func,
                        this->uap,
                        evAddTime((this->mode & EV_TMR_RATE) ?
                              this->due :
                              ctx->lastEventTime,
                              this->inter),
                        this->inter);
        }
        break;
        }
        case Wait: {
        FREE(ev->u.wait.this);
        break;
        }
        case Null: {
        /* No work. */
        break;
        }
        default: {
        abort();
        }
    }
    FREE(ev);
}

int
evMainLoop(evContext opaqueCtx) {
    evEvent event;
    int x;

    while ((x = evGetNext(opaqueCtx, &event, EV_WAIT)) == 0)
        if ((x = evDispatch(opaqueCtx, event)) < 0)
            break;
    return (x);
}

int
evHighestFD(evContext opaqueCtx) {
    evContext_p *ctx = opaqueCtx.opaque;

    return (ctx->highestFD);
}

void
evPrintf(const evContext_p *ctx, int level, const char *fmt, ...) {
    va_list ap;

    va_start(ap, fmt);
    if (ctx->output != NULL && ctx->debug >= level) {
        vfprintf(ctx->output, fmt, ap);
        fflush(ctx->output);
    }
    va_end(ap);
}

int
evSetOption(evContext *opaqueCtx, const char *option, int value) {
    /* evContext_p *ctx = opaqueCtx->opaque; */

    UNUSED(opaqueCtx);
    UNUSED(value);
#ifndef CLOCK_MONOTONIC
    UNUSED(option);
#endif

#ifdef CLOCK_MONOTONIC
    if (strcmp(option, "monotime") == 0) {
        if (opaqueCtx  != NULL)
            errno = EINVAL;
        if (value == 0 || value == 1) {
            __evOptMonoTime = value;
            return (0);
        } else {
            errno = EINVAL;
            return (-1);
        }
    }
#endif
    errno = ENOENT;
    return (-1);
}

int
evGetOption(evContext *opaqueCtx, const char *option, int *value) {
    /* evContext_p *ctx = opaqueCtx->opaque; */

    UNUSED(opaqueCtx);
#ifndef CLOCK_MONOTONIC
    UNUSED(value);
    UNUSED(option);
#endif

#ifdef CLOCK_MONOTONIC
    if (strcmp(option, "monotime") == 0) {
        if (opaqueCtx  != NULL)
            errno = EINVAL;
        *value = __evOptMonoTime;
        return (0);
    }
#endif
    errno = ENOENT;
    return (-1);
}

#if defined(NEED_PSELECT) || defined(USE_POLL)
/* XXX needs to move to the porting library. */
static int
pselect(int nfds, void *rfds, void *wfds, void *efds,
    struct timespec *tsp,
    const sigset_t *sigmask)
{
    struct timeval tv, *tvp;
    sigset_t sigs;
    int n;
#ifdef USE_POLL
    int polltimeout = INFTIM;
    evContext_p *ctx;
    struct pollfd   *fds;
    nfds_t      pnfds;

    UNUSED(nfds);
#endif /* USE_POLL */

    if (tsp) {
        tvp = &tv;
        tv = evTimeVal(*tsp);
#ifdef USE_POLL
        polltimeout = 1000 * tv.tv_sec + tv.tv_usec / 1000;
#endif /* USE_POLL */
    } else
        tvp = NULL;
    if (sigmask)
        sigprocmask(SIG_SETMASK, sigmask, &sigs);
#ifndef USE_POLL
     n = select(nfds, rfds, wfds, efds, tvp);
#else
        /*
     * rfds, wfds, and efds should all be from the same evContext_p,
     * so any of them will do. If they're all NULL, the caller is
     * presumably calling us to block.
     */
    if (rfds != NULL)
        ctx = ((__evEmulMask *)rfds)->ctx;
    else if (wfds != NULL)
        ctx = ((__evEmulMask *)wfds)->ctx;
    else if (efds != NULL)
        ctx = ((__evEmulMask *)efds)->ctx;
    else
        ctx = NULL;
    if (ctx != NULL && ctx->fdMax != -1) {
        fds = &(ctx->pollfds[ctx->firstfd]);
        pnfds = ctx->fdMax - ctx->firstfd + 1;
    } else {
        fds = NULL;
        pnfds = 0;
    }
    n = poll(fds, pnfds, polltimeout);
    if (n > 0) {
        int     i, e;

        INSIST(ctx != NULL);
        for (e = 0, i = ctx->firstfd; i <= ctx->fdMax; i++) {
            if (ctx->pollfds[i].fd < 0)
                continue;
            if (FD_ISSET(i, &ctx->rdLast))
                e++;
            if (FD_ISSET(i, &ctx->wrLast))
                e++;
            if (FD_ISSET(i, &ctx->exLast))
                e++;
        }
        n = e;
    }
#endif /* USE_POLL */
    if (sigmask)
        sigprocmask(SIG_SETMASK, &sigs, NULL);
    if (tsp)
        *tsp = evTimeSpec(tv);
    return (n);
}
#endif

#ifdef USE_POLL
int
evPollfdRealloc(evContext_p *ctx, int pollfd_chunk_size, int fd) {

    int     i, maxnfds;
    void    *pollfds, *fdTable;

    if (fd < ctx->maxnfds)
        return (0);

    /* Don't allow ridiculously small values for pollfd_chunk_size */
    if (pollfd_chunk_size < 20)
        pollfd_chunk_size = 20;

    maxnfds = (1 + (fd/pollfd_chunk_size)) * pollfd_chunk_size;

    pollfds = realloc(ctx->pollfds, maxnfds * sizeof(*ctx->pollfds));
    if (pollfds != NULL)
        ctx->pollfds = pollfds;
    fdTable = realloc(ctx->fdTable, maxnfds * sizeof(*ctx->fdTable));
    if (fdTable != NULL)
        ctx->fdTable = fdTable;

    if (pollfds == NULL || fdTable == NULL) {
        evPrintf(ctx, 2, "pollfd() realloc (%ld) failed\n",
             (long)maxnfds*sizeof(struct pollfd));
        return (-1);
    }

    for (i = ctx->maxnfds; i < maxnfds; i++) {
        ctx->pollfds[i].fd = -1;
        ctx->pollfds[i].events = 0;
        ctx->fdTable[i] = 0;
    }

    ctx->maxnfds = maxnfds;

    return (0);
}

/* Find the appropriate 'events' or 'revents' field in the pollfds array */
short *
__fd_eventfield(int fd, __evEmulMask *maskp) {

    evContext_p     *ctx = (evContext_p *)maskp->ctx;

    if (!maskp->result || maskp->type == EV_WASNONBLOCKING)
        return (&(ctx->pollfds[fd].events));
    else
        return (&(ctx->pollfds[fd].revents));
}

/* Translate to poll(2) event */
short
__poll_event(__evEmulMask *maskp) {

    switch ((maskp)->type) {
    case EV_READ:
        return (POLLRDNORM);
    case EV_WRITE:
        return (POLLWRNORM);
    case EV_EXCEPT:
        return (POLLRDBAND | POLLPRI | POLLWRBAND);
    case EV_WASNONBLOCKING:
        return (POLLHUP);
    default:
        return (0);
    }
}

/*
 * Clear the events corresponding to the specified mask. If this leaves
 * the events mask empty (apart from the POLLHUP bit), set the fd field
 * to -1 so that poll(2) will ignore this fd.
 */
void
__fd_clr(int fd, __evEmulMask *maskp) {

    evContext_p     *ctx = maskp->ctx;

    *__fd_eventfield(fd, maskp) &= ~__poll_event(maskp);
    if ((ctx->pollfds[fd].events & ~POLLHUP) == 0) {
        ctx->pollfds[fd].fd = -1;
        if (fd == ctx->fdMax)
            while (ctx->fdMax > ctx->firstfd &&
                   ctx->pollfds[ctx->fdMax].fd < 0)
                ctx->fdMax--;
        if (fd == ctx->firstfd)
            while (ctx->firstfd <= ctx->fdMax &&
                   ctx->pollfds[ctx->firstfd].fd < 0)
                ctx->firstfd++;
        /*
         * Do we have a empty set of descriptors?
         */
        if (ctx->firstfd > ctx->fdMax) {
            ctx->fdMax = -1;
            ctx->firstfd = 0;
        }
    }
}

/*
 * Set the events bit(s) corresponding to the specified mask. If the events
 * field has any other bits than POLLHUP set, also set the fd field so that
 * poll(2) will watch this fd.
 */
void
__fd_set(int fd, __evEmulMask *maskp) {

    evContext_p     *ctx = maskp->ctx;

    *__fd_eventfield(fd, maskp) |= __poll_event(maskp);
    if ((ctx->pollfds[fd].events & ~POLLHUP) != 0) {
        ctx->pollfds[fd].fd = fd;
        if (fd < ctx->firstfd || ctx->fdMax == -1)
            ctx->firstfd = fd;
        if (fd > ctx->fdMax)
            ctx->fdMax = fd;
    }
}
#endif /* USE_POLL */

/*! \file */