source: rtems-libbsd/freebsd/lib/libc/isc/ev_streams.c @ e599318

/*
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1996-1999 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.
 */

/* ev_streams.c - implement asynch stream file IO for the eventlib
 * vix 04mar96 [initial]
 */

#if !defined(LINT) && !defined(CODECENTER)
static const char rcsid[] = "$Id: ev_streams.c,v 1.4.18.1 2005/04/27 05:01:06 sra Exp $";
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include "port_before.h"
#ifndef _LIBC
#include "fd_setsize.h"
#endif

#include <rtems/bsd/sys/types.h>
#include <sys/uio.h>

#include <errno.h>

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

#include "port_after.h"

#ifndef _LIBC
static int      copyvec(evStream *str, const struct iovec *iov, int iocnt);
static void     consume(evStream *str, size_t bytes);
static void     done(evContext opaqueCtx, evStream *str);
static void     writable(evContext opaqueCtx, void *uap, int fd, int evmask);
static void     readable(evContext opaqueCtx, void *uap, int fd, int evmask);
#endif

struct iovec
evConsIovec(void *buf, size_t cnt) {
        struct iovec ret;

        memset(&ret, 0xf5, sizeof ret);
        ret.iov_base = buf;
        ret.iov_len = cnt;
        return (ret);
}

#ifndef _LIBC
int
evWrite(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
        evStreamFunc func, void *uap, evStreamID *id)
{
        evContext_p *ctx = opaqueCtx.opaque;
        evStream *new;
        int save;

        OKNEW(new);
        new->func = func;
        new->uap = uap;
        new->fd = fd;
        new->flags = 0;
        if (evSelectFD(opaqueCtx, fd, EV_WRITE, writable, new, &new->file) < 0)
                goto free;
        if (copyvec(new, iov, iocnt) < 0)
                goto free;
        new->prevDone = NULL;
        new->nextDone = NULL;
        if (ctx->streams != NULL)
                ctx->streams->prev = new;
        new->prev = NULL;
        new->next = ctx->streams;
        ctx->streams = new;
        if (id != NULL)
                id->opaque = new;
        return (0);
 free:
        save = errno;
        FREE(new);
        errno = save;
        return (-1);
}

int
evRead(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
       evStreamFunc func, void *uap, evStreamID *id)
{
        evContext_p *ctx = opaqueCtx.opaque;
        evStream *new;
        int save;

        OKNEW(new);
        new->func = func;
        new->uap = uap;
        new->fd = fd;
        new->flags = 0;
        if (evSelectFD(opaqueCtx, fd, EV_READ, readable, new, &new->file) < 0)
                goto free;
        if (copyvec(new, iov, iocnt) < 0)
                goto free;
        new->prevDone = NULL;
        new->nextDone = NULL;
        if (ctx->streams != NULL)
                ctx->streams->prev = new;
        new->prev = NULL;
        new->next = ctx->streams;
        ctx->streams = new;
        if (id)
                id->opaque = new;
        return (0);
 free:
        save = errno;
        FREE(new);
        errno = save;
        return (-1);
}

int
evTimeRW(evContext opaqueCtx, evStreamID id, evTimerID timer) /*ARGSUSED*/ {
        evStream *str = id.opaque;

        UNUSED(opaqueCtx);

        str->timer = timer;
        str->flags |= EV_STR_TIMEROK;
        return (0);
}

int
evUntimeRW(evContext opaqueCtx, evStreamID id) /*ARGSUSED*/ {
        evStream *str = id.opaque;

        UNUSED(opaqueCtx);

        str->flags &= ~EV_STR_TIMEROK;
        return (0);
}

int
evCancelRW(evContext opaqueCtx, evStreamID id) {
        evContext_p *ctx = opaqueCtx.opaque;
        evStream *old = id.opaque;

        /*
         * The streams list is doubly threaded.  First, there's ctx->streams
         * that's used by evDestroy() to find and cancel all streams.  Second,
         * there's ctx->strDone (head) and ctx->strLast (tail) which thread
         * through the potentially smaller number of "IO completed" streams,
         * used in evGetNext() to avoid scanning the entire list.
         */

        /* Unlink from ctx->streams. */
        if (old->prev != NULL)
                old->prev->next = old->next;
        else
                ctx->streams = old->next;
        if (old->next != NULL)
                old->next->prev = old->prev;

        /*
         * If 'old' is on the ctx->strDone list, remove it.  Update
         * ctx->strLast if necessary.
         */
        if (old->prevDone == NULL && old->nextDone == NULL) {
                /*
                 * Either 'old' is the only item on the done list, or it's
                 * not on the done list.  If the former, then we unlink it
                 * from the list.  If the latter, we leave the list alone.
                 */
                if (ctx->strDone == old) {
                        ctx->strDone = NULL;
                        ctx->strLast = NULL;
                }
        } else {
                if (old->prevDone != NULL)
                        old->prevDone->nextDone = old->nextDone;
                else
                        ctx->strDone = old->nextDone;
                if (old->nextDone != NULL)
                        old->nextDone->prevDone = old->prevDone;
                else
                        ctx->strLast = old->prevDone;
        }

        /* Deallocate the stream. */
        if (old->file.opaque)
                evDeselectFD(opaqueCtx, old->file);
        memput(old->iovOrig, sizeof (struct iovec) * old->iovOrigCount);
        FREE(old);
        return (0);
}

/* Copy a scatter/gather vector and initialize a stream handler's IO. */
static int
copyvec(evStream *str, const struct iovec *iov, int iocnt) {
        int i;

        str->iovOrig = (struct iovec *)memget(sizeof(struct iovec) * iocnt);
        if (str->iovOrig == NULL) {
                errno = ENOMEM;
                return (-1);
        }
        str->ioTotal = 0;
        for (i = 0; i < iocnt; i++) {
                str->iovOrig[i] = iov[i];
                str->ioTotal += iov[i].iov_len;
        }
        str->iovOrigCount = iocnt;
        str->iovCur = str->iovOrig;
        str->iovCurCount = str->iovOrigCount;
        str->ioDone = 0;
        return (0);
}

/* Pull off or truncate lead iovec(s). */
static void
consume(evStream *str, size_t bytes) {
        while (bytes > 0U) {
                if (bytes < (size_t)str->iovCur->iov_len) {
                        str->iovCur->iov_len -= bytes;
                        str->iovCur->iov_base = (void *)
                                ((u_char *)str->iovCur->iov_base + bytes);
                        str->ioDone += bytes;
                        bytes = 0;
                } else {
                        bytes -= str->iovCur->iov_len;
                        str->ioDone += str->iovCur->iov_len;
                        str->iovCur++;
                        str->iovCurCount--;
                }
        }
}

/* Add a stream to Done list and deselect the FD. */
static void
done(evContext opaqueCtx, evStream *str) {
        evContext_p *ctx = opaqueCtx.opaque;

        if (ctx->strLast != NULL) {
                str->prevDone = ctx->strLast;
                ctx->strLast->nextDone = str;
                ctx->strLast = str;
        } else {
                INSIST(ctx->strDone == NULL);
                ctx->strDone = ctx->strLast = str;
        }
        evDeselectFD(opaqueCtx, str->file);
        str->file.opaque = NULL;
        /* evDrop() will call evCancelRW() on us. */
}

/* Dribble out some bytes on the stream.  (Called by evDispatch().) */
static void
writable(evContext opaqueCtx, void *uap, int fd, int evmask) {
        evStream *str = uap;
        int bytes;

        UNUSED(evmask);

        bytes = writev(fd, str->iovCur, str->iovCurCount);
        if (bytes > 0) {
                if ((str->flags & EV_STR_TIMEROK) != 0)
                        evTouchIdleTimer(opaqueCtx, str->timer);
                consume(str, bytes);
        } else {
                if (bytes < 0 && errno != EINTR) {
                        str->ioDone = -1;
                        str->ioErrno = errno;
                }
        }
        if (str->ioDone == -1 || str->ioDone == str->ioTotal)
                done(opaqueCtx, str);
}

/* Scoop up some bytes from the stream.  (Called by evDispatch().) */
static void
readable(evContext opaqueCtx, void *uap, int fd, int evmask) {
        evStream *str = uap;
        int bytes;

        UNUSED(evmask);

        bytes = readv(fd, str->iovCur, str->iovCurCount);
        if (bytes > 0) {
                if ((str->flags & EV_STR_TIMEROK) != 0)
                        evTouchIdleTimer(opaqueCtx, str->timer);
                consume(str, bytes);
        } else {
                if (bytes == 0)
                        str->ioDone = 0;
                else {
                        if (errno != EINTR) {
                                str->ioDone = -1;
                                str->ioErrno = errno;
                        }
                }
        }
        if (str->ioDone <= 0 || str->ioDone == str->ioTotal)
                done(opaqueCtx, str);
}
#endif

/*! \file */