SRead.c

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#include "syshdrs.h"

static char UNUSED(gSioVersion[]) = "@(#) sio 6.0.3 ** Copyright 1992-2001 Mike Gleason. All rights reserved.";

#ifdef NO_SIGNALS
static char UNUSED(gNoSignalsMarker[]) = "@(#) sio - NO_SIGNALS";
#else
extern volatile Sjmp_buf gNetTimeoutJmp;
extern volatile Sjmp_buf gPipeJmp;
#endif

/* Read up to "size" bytes on sfd before "tlen" seconds.
 *
 * If "retry" is on, after a successful read of less than "size"
 * bytes, it will attempt to read more, upto "size."
 *
 * If the timer elapses and one or more bytes were read, it returns
 * that number, otherwise a timeout error is returned.
 *
 * Although "retry" would seem to indicate you may want to always
 * read "size" bytes or else it is an error, even with that on you
 * may get back a value < size.  Set "retry" to 0 when you want to
 * return as soon as there is a chunk of data whose size is <= "size".
 */

#ifndef NO_SIGNALS

int
SRead(int sfd, char *const buf0, size_t size, int tlen, int retry)
{
    int nread;
    volatile int nleft;
    char *volatile buf = buf0;
    int tleft;
    vsio_sigproc_t sigalrm, sigpipe;
    time_t done, now;

    if (SSetjmp(gNetTimeoutJmp) != 0) {
        alarm(0);
        (void) SSignal(SIGALRM, (sio_sigproc_t) sigalrm);
        (void) SSignal(SIGPIPE, (sio_sigproc_t) sigpipe);
        nread = size - nleft;
        if ((nread > 0) && ((retry & (kFullBufferRequired|kFullBufferRequiredExceptLast)) == 0))
            return (nread);
        errno = ETIMEDOUT;
        return (kTimeoutErr);
    }

    if (SSetjmp(gPipeJmp) != 0) {
        alarm(0);
        (void) SSignal(SIGALRM, (sio_sigproc_t) sigalrm);
        (void) SSignal(SIGPIPE, (sio_sigproc_t) sigpipe);
        nread = size - nleft;
        if ((nread > 0) && ((retry & (kFullBufferRequired|kFullBufferRequiredExceptLast)) == 0))
            return (nread);
        errno = EPIPE;
        return (kBrokenPipeErr);
    }

    sigalrm = (vsio_sigproc_t) SSignal(SIGALRM, SIOHandler);
    sigpipe = (vsio_sigproc_t) SSignal(SIGPIPE, SIOHandler);
    errno = 0;

    nleft = (int) size;
    time(&now);
    done = now + tlen;
    forever {
        tleft = (int) (done - now);
        if (tleft < 1) {
            nread = size - nleft;
            if ((nread == 0) || ((retry & (kFullBufferRequired)) != 0)) {
                nread = kTimeoutErr;
                errno = ETIMEDOUT;
            }
            goto done;
        }
        (void) alarm((unsigned int) tleft);
        nread = read(sfd, (char *) buf, nleft);
        (void) alarm(0);
        if (nread <= 0) {
            if (nread == 0) {
                /* EOF */
                if (retry == ((retry & (kFullBufferRequiredExceptLast)) != 0))
                    nread = size - nleft;
                goto done;
            } else if (errno != EINTR) {
                nread = size - nleft;
                if (nread == 0)
                    nread = -1;
                goto done;
            } else {
                errno = 0;
                nread = 0;
                /* Try again. */

                /* Ignore this line... */
                LIBSIO_USE_VAR(gSioVersion);
            }
        }
        nleft -= nread;
        if ((nleft <= 0) || (((retry & (kFullBufferRequired|kFullBufferRequiredExceptLast)) == 0) && (nleft != (int) size)))
            break;
        buf += nread;
        time(&now);
    }
    nread = size - nleft;

done:
    (void) SSignal(SIGALRM, (sio_sigproc_t) sigalrm);
    (void) SSignal(SIGPIPE, (sio_sigproc_t) sigpipe);

    return (nread);
}   /* SRead */

#else

int
SRead(int sfd, char *const buf0, size_t size, int tlen, int retry)
{
    int nread;
    volatile int nleft;
    char *buf = buf0;
    int tleft;
    time_t done, now;
    fd_set ss;
    struct timeval tv;
    int result, firstRead;

    errno = 0;

    nleft = (int) size;
    time(&now);
    done = now + tlen;
    firstRead = 1;

    forever {
        tleft = (int) (done - now);
        if (tleft < 1) {
            nread = size - nleft;
            if ((nread == 0) || ((retry & (kFullBufferRequired|kFullBufferRequiredExceptLast)) != 0)) {
                nread = kTimeoutErr;
                errno = ETIMEDOUT;
                SETWSATIMEOUTERR
            }
            goto done;
        }

        if (!firstRead || ((retry & kNoFirstSelect) == 0)) {
            forever {
                errno = 0;
                FD_ZERO(&ss);
                FD_SET(sfd, &ss);
                tv.tv_sec = tlen;
                tv.tv_usec = 0;
                result = select(sfd + 1, SELECT_TYPE_ARG234 &ss, NULL, NULL, SELECT_TYPE_ARG5 &tv);
                if (result == 1) {
                    /* ready */
                    break;
                } else if (result == 0) {
                    /* timeout */
                    nread = size - nleft;
                    if ((nread > 0) && ((retry & (kFullBufferRequired|kFullBufferRequiredExceptLast)) == 0))
                        return (nread);
                    errno = ETIMEDOUT;
                    SETWSATIMEOUTERR
                        return (kTimeoutErr);
                } else if (errno != EINTR) {
                    return (-1);
                }
            }
            firstRead = 0;
        }

#if defined(WIN32) || defined(_WINDOWS)
        nread = recv(sfd, (char *) buf, nleft, 0);
#else
        nread = read(sfd, (char *) buf, nleft);
#endif

        if (nread <= 0) {
            if (nread == 0) {
                /* EOF */
                if (retry == ((retry & (kFullBufferRequiredExceptLast)) != 0))
                    nread = size - nleft;
                goto done;
            } else if (errno != EINTR) {
                nread = size - nleft;
                if (nread == 0)
                    nread = -1;
                goto done;
            } else {
                errno = 0;
                nread = 0;
                /* Try again. */

                /* Ignore these two lines */
                LIBSIO_USE_VAR(gSioVersion);
                LIBSIO_USE_VAR(gNoSignalsMarker);
            }
        }
        nleft -= nread;
        if ((nleft <= 0) || (((retry & (kFullBufferRequired|kFullBufferRequiredExceptLast)) == 0) && (nleft != (int) size)))
            break;
        buf += nread;
        time(&now);
    }
    nread = size - nleft;

done:
    return (nread);
}   /* SRead */

#endif