sendrecv.c

apache的软件linux版本

            if (apr_is_option_set(sock->netmask, APR_SO_TIMEOUT)) {
                sock->netmask |= APR_INCOMPLETE_WRITE;
            }
            return arv;
        }
        else {
            /* If the file got smaller mid-request, eventually the offset
             * becomes equal to the new file size and the kernel returns 0.  
             * Make this an error so the caller knows to log something and
             * exit.
             */
            return APR_EOF;
        }
    }

    /* Now write the footers */
    if (hdtr->numtrailers > 0) {
        apr_size_t trbytes;
        arv = apr_socket_sendv(sock, hdtr->trailers, hdtr->numtrailers, 
                               &trbytes);
        nbytes += trbytes;
        if (arv != APR_SUCCESS) {
            *len = nbytes;
            rv = errno;
            apr_socket_opt_set(sock, APR_TCP_NOPUSH, 0);
            return rv;
        }
    }

    apr_socket_opt_set(sock, APR_TCP_NOPUSH, 0);
    
    (*len) = nbytes;
    return rv < 0 ? errno : APR_SUCCESS;
}

#elif defined(__FreeBSD__)

static int include_hdrs_in_length(void)
{
#ifdef HAVE_SYS_SYSCTL_H
/* this assumes: 
 *   if the header exists, so does the sysctlbyname() syscall, and 
 *   if the header doesn't exist, the kernel is really old
 */

/* see 
 * http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/sys/param.h#rev1.61.2.29 
 * for kernel version number
 * 
 * http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/kern/uipc_syscalls.c#rev1.65.2.10
 * for the sendfile patch
 */
#define KERNEL_WITH_SENDFILE_LENGTH_FIX 460001

    typedef enum { UNKNOWN = 0, 
                   NEW, 
                   OLD 
                 } api_e;

    static api_e api; 
    int kernel_version;  
    apr_size_t kernel_version_size;

    if (api != UNKNOWN) {
        return (api == OLD);
    }
    kernel_version = 0;    /* silence compiler warning */
    kernel_version_size = sizeof(kernel_version);
    if (sysctlbyname("kern.osreldate", &kernel_version, 
                     &kernel_version_size, NULL, 0) == 0 &&
        kernel_version < KERNEL_WITH_SENDFILE_LENGTH_FIX) {
        api = OLD;
        return 1;
    }
    /* size of kern.osreldate's output might change in the future 
     * causing the sysctlbyname to fail,
     * but if it's the future, we should use the newer API 
     */
    api = NEW;
    return 0;
#else
    /* the build system's kernel is older than 3.4.  Use the old API */
    return 1;
#endif
}

/* Release 3.1 or greater */
apr_status_t apr_socket_sendfile(apr_socket_t * sock, apr_file_t * file,
                                 apr_hdtr_t * hdtr, apr_off_t * offset,
                                 apr_size_t * len, apr_int32_t flags)
{
    off_t nbytes = 0;
    int rv, i;
    struct sf_hdtr headerstruct;
    apr_size_t bytes_to_send = *len;

    /* Ignore flags for now. */
    flags = 0;

    if (!hdtr) {
        hdtr = &no_hdtr;
    }

    else if (hdtr->numheaders && include_hdrs_in_length()) {

        /* On early versions of FreeBSD sendfile, the number of bytes to send 
         * must include the length of the headers.  Don't look at the man page 
         * for this :(  Instead, look at the the logic in 
         * src/sys/kern/uipc_syscalls::sendfile().
         *
         * This was fixed in the middle of 4.6-STABLE
         */
        for (i = 0; i < hdtr->numheaders; i++) {
            bytes_to_send += hdtr->headers[i].iov_len;
        }
    }

    headerstruct.headers = hdtr->headers;
    headerstruct.hdr_cnt = hdtr->numheaders;
    headerstruct.trailers = hdtr->trailers;
    headerstruct.trl_cnt = hdtr->numtrailers;

    /* FreeBSD can send the headers/footers as part of the system call */
    do {
        if (sock->netmask & APR_INCOMPLETE_WRITE) {
            apr_status_t arv;
            sock->netmask &= ~APR_INCOMPLETE_WRITE;
            arv = apr_wait_for_io_or_timeout(NULL, sock, 0);
            if (arv != APR_SUCCESS) {
                *len = 0;
                return arv;
            }
        }
        if (bytes_to_send) {
            /* We won't dare call sendfile() if we don't have
             * header or file bytes to send because bytes_to_send == 0
             * means send the whole file.
             */
            rv = sendfile(file->filedes, /* file to be sent */
                          sock->socketdes, /* socket */
                          *offset,       /* where in the file to start */
                          bytes_to_send, /* number of bytes to send */
                          &headerstruct, /* Headers/footers */
                          &nbytes,       /* number of bytes written */
                          flags);        /* undefined, set to 0 */

            if (rv == -1) {
                if (errno == EAGAIN) {
                    if (apr_is_option_set(sock->netmask, APR_SO_TIMEOUT)) {
                        sock->netmask |= APR_INCOMPLETE_WRITE;
                    }
                    /* FreeBSD's sendfile can return -1/EAGAIN even if it
                     * sent bytes.  Sanitize the result so we get normal EAGAIN
                     * semantics w.r.t. bytes sent.
                     */
                    if (nbytes) {
                        /* normal exit for a big file & non-blocking io */
                        (*len) = nbytes;
                        return APR_SUCCESS;
                    }
                }
            }
            else {       /* rv == 0 (or the kernel is broken) */
                if (nbytes == 0) {
                    /* Most likely the file got smaller after the stat.
                     * Return an error so the caller can do the Right Thing.
                     */
                    (*len) = nbytes;
                    return APR_EOF;
                }
            }
        }    
        else {
            /* just trailer bytes... use writev()
             */
            rv = writev(sock->socketdes,
                        hdtr->trailers,
                        hdtr->numtrailers);
            if (rv > 0) {
                nbytes = rv;
                rv = 0;
            }
            else {
                nbytes = 0;
            }
        }
        if (rv == -1 &&
            errno == EAGAIN && 
            apr_is_option_set(sock->netmask, APR_SO_TIMEOUT)) {
            apr_status_t arv = apr_wait_for_io_or_timeout(NULL, sock, 0);
            if (arv != APR_SUCCESS) {
                *len = 0;
                return arv;
            }
        }
    } while (rv == -1 && (errno == EINTR || errno == EAGAIN));

    (*len) = nbytes;
    if (rv == -1) {
        return errno;
    }
    return APR_SUCCESS;
}

#elif defined(__hpux) || defined(__hpux__)

/* HP cc in ANSI mode defines __hpux; gcc defines __hpux__ */

/* HP-UX Version 10.30 or greater
 * (no worries, because we only get here if autoconfiguration found sendfile)
 */

/* ssize_t sendfile(int s, int fd, off_t offset, size_t nbytes,
 *                  const struct iovec *hdtrl, int flags);
 *
 * nbytes is the number of bytes to send just from the file; as with FreeBSD, 
 * if nbytes == 0, the rest of the file (from offset) is sent
 */

apr_status_t apr_socket_sendfile(apr_socket_t *sock, apr_file_t *file,
                                 apr_hdtr_t *hdtr, apr_off_t *offset,
                                 apr_size_t *len, apr_int32_t flags)
{
    int i;
    apr_ssize_t rc;
    apr_size_t nbytes = *len, headerlen, trailerlen;
    struct iovec hdtrarray[2];
    char *headerbuf, *trailerbuf;

    if (!hdtr) {
        hdtr = &no_hdtr;
    }

    /* Ignore flags for now. */
    flags = 0;

    /* HP-UX can only send one header iovec and one footer iovec; try to
     * only allocate storage to combine input iovecs when we really have to
     */

    switch(hdtr->numheaders) {
    case 0:
        hdtrarray[0].iov_base = NULL;
        hdtrarray[0].iov_len = 0;
        break;
    case 1:
        hdtrarray[0] = hdtr->headers[0];
        break;
    default:
        headerlen = 0;
        for (i = 0; i < hdtr->numheaders; i++) {
            headerlen += hdtr->headers[i].iov_len;
        }  

        /* XXX:  BUHHH? wow, what a memory leak! */
        headerbuf = hdtrarray[0].iov_base = apr_palloc(sock->cntxt, headerlen);
        hdtrarray[0].iov_len = headerlen;

        for (i = 0; i < hdtr->numheaders; i++) {
            memcpy(headerbuf, hdtr->headers[i].iov_base,
                   hdtr->headers[i].iov_len);
            headerbuf += hdtr->headers[i].iov_len;
        }
    }

    switch(hdtr->numtrailers) {
    case 0:
        hdtrarray[1].iov_base = NULL;
        hdtrarray[1].iov_len = 0;
        break;
    case 1:
        hdtrarray[1] = hdtr->trailers[0];
        break;
    default:
        trailerlen = 0;
        for (i = 0; i < hdtr->numtrailers; i++) {
            trailerlen += hdtr->trailers[i].iov_len;
        }

        /* XXX:  BUHHH? wow, what a memory leak! */
        trailerbuf = hdtrarray[1].iov_base = apr_palloc(sock->cntxt, trailerlen);
        hdtrarray[1].iov_len = trailerlen;

        for (i = 0; i < hdtr->numtrailers; i++) {
            memcpy(trailerbuf, hdtr->trailers[i].iov_base,
                   hdtr->trailers[i].iov_len);
            trailerbuf += hdtr->trailers[i].iov_len;
        }
    }

    do {
        if (nbytes) {       /* any bytes to send from the file? */
            rc = sendfile(sock->socketdes,      /* socket  */
                          file->filedes,        /* file descriptor to send */
                          *offset,              /* where in the file to start */
                          nbytes,               /* number of bytes to send from file */
                          hdtrarray,            /* Headers/footers */
                          flags);               /* undefined, set to 0 */
        }
        else {              /* we can't call sendfile() with no bytes to send from the file */
            rc = writev(sock->socketdes, hdtrarray, 2);
        }
    } while (rc == -1 && errno == EINTR);

    while (rc == -1 && 
        (errno == EAGAIN || errno == EWOULDBLOCK) && 
        apr_is_option_set(sock->netmask, APR_SO_TIMEOUT)) {
        apr_status_t arv = apr_wait_for_io_or_timeout(NULL, sock, 0);

        if (arv != APR_SUCCESS) {
            *len = 0;
            return arv;
        }
        else {
            do {
                if (nbytes) {
                    rc = sendfile(sock->socketdes,    /* socket  */
                                  file->filedes,      /* file descriptor to send */
                                  *offset,            /* where in the file to start */
                                  nbytes,             /* number of bytes to send from file */
                                  hdtrarray,          /* Headers/footers */
                                  flags);             /* undefined, set to 0 */
                }
                else {      /* we can't call sendfile() with no bytes to send from the file */
                    rc = writev(sock->socketdes, hdtrarray, 2);
                }
            } while (rc == -1 && errno == EINTR);
        }
    }

    if (rc == -1) {
        *len = 0;
        return errno;
    }

    /* Set len to the number of bytes written */
    *len = rc;
    return APR_SUCCESS;
}