source: branches/samba-3.2.x/source/lib/sendfile.c@ 232

/*
 Unix SMB/Netbios implementation.
 Version 2.2.x / 3.0.x
 sendfile implementations.
 Copyright (C) Jeremy Allison 2002.

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 3 of the License, or
 (at your option) any later version.
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, see <http://www.gnu.org/licenses/>.
*/

/*
 * This file handles the OS dependent sendfile implementations.
 * The API is such that it returns -1 on error, else returns the
 * number of bytes written.
 */

#include "includes.h"

#if defined(LINUX_SENDFILE_API)

#include <sys/sendfile.h>

#ifndef MSG_MORE
#define MSG_MORE 0x8000
#endif

ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
{
        size_t total=0;
        ssize_t ret;
        size_t hdr_len = 0;

        /*
         * Send the header first.
         * Use MSG_MORE to cork the TCP output until sendfile is called.
         */

        if (header) {
                hdr_len = header->length;
                while (total < hdr_len) {
                        ret = sys_send(tofd, header->data + total,hdr_len - total, MSG_MORE);
                        if (ret == -1)
                                return -1;
                        total += ret;
                }
        }

        total = count;
        while (total) {
                ssize_t nwritten;
                do {
#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_OFF64_T) && defined(HAVE_SENDFILE64)
                        nwritten = sendfile64(tofd, fromfd, &offset, total);
#else
                        nwritten = sendfile(tofd, fromfd, &offset, total);
#endif
                } while (nwritten == -1 && errno == EINTR);
                if (nwritten == -1) {
                        if (errno == ENOSYS || errno == EINVAL) {
                                /* Ok - we're in a world of pain here. We just sent
                                 * the header, but the sendfile failed. We have to
                                 * emulate the sendfile at an upper layer before we
                                 * disable it's use. So we do something really ugly.
                                 * We set the errno to a strange value so we can detect
                                 * this at the upper level and take care of it without
                                 * layer violation. JRA.
                                 */
                                errno = EINTR; /* Normally we can never return this. */
                        }
                        return -1;
                }
                if (nwritten == 0)
                        return -1; /* I think we're at EOF here... */
                total -= nwritten;
        }
        return count + hdr_len;
}

#elif defined(LINUX_BROKEN_SENDFILE_API)

/*
 * We must use explicit 32 bit types here. This code path means Linux
 * won't do proper 64-bit sendfile. JRA.
 */

extern int32 sendfile (int out_fd, int in_fd, int32 *offset, uint32 count);


#ifndef MSG_MORE
#define MSG_MORE 0x8000
#endif

ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
{
        size_t total=0;
        ssize_t ret;
        ssize_t hdr_len = 0;
        uint32 small_total = 0;
        int32 small_offset;