source: branches/samba-3.2.x/source/lib/util_transfer_file.c

/*
 * Unix SMB/CIFS implementation.
 * Utility functions to transfer files.
 *
 * Copyright (C) Jeremy Allison 2001-2002
 * Copyright (C) Michael Adam 2008
 *
 * 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/>.
 */


#include <includes.h>

/****************************************************************************
 Transfer some data between two fd's.
****************************************************************************/

#ifndef TRANSFER_BUF_SIZE
#define TRANSFER_BUF_SIZE 65536
#endif


ssize_t transfer_file_internal(void *in_file,
                               void *out_file,
                               size_t n,
                               ssize_t (*read_fn)(void *, void *, size_t),
                               ssize_t (*write_fn)(void *, const void *, size_t))
{
        char *buf;
        size_t total = 0;
        ssize_t read_ret;
        ssize_t write_ret;
        size_t num_to_read_thistime;
        size_t num_written = 0;

        if ((buf = SMB_MALLOC_ARRAY(char, TRANSFER_BUF_SIZE)) == NULL) {
                return -1;
        }

        while (total < n) {
                num_to_read_thistime = MIN((n - total), TRANSFER_BUF_SIZE);

                read_ret = (*read_fn)(in_file, buf, num_to_read_thistime);
                if (read_ret == -1) {
                        DEBUG(0,("transfer_file_internal: read failure. "
                                 "Error = %s\n", strerror(errno) ));
                        SAFE_FREE(buf);
                        return -1;
                }
                if (read_ret == 0) {
                        break;
                }

                num_written = 0;

                while (num_written < read_ret) {
                        write_ret = (*write_fn)(out_file, buf + num_written,
                                                read_ret - num_written);

                        if (write_ret == -1) {
                                DEBUG(0,("transfer_file_internal: "
                                         "write failure. Error = %s\n",
                                         strerror(errno) ));
                                SAFE_FREE(buf);
                                return -1;
                        }
                        if (write_ret == 0) {
                                return (ssize_t)total;
                        }

                        num_written += (size_t)write_ret;
                }

                total += (size_t)read_ret;
        }

        SAFE_FREE(buf);
        return (ssize_t)total;
}

static ssize_t sys_read_fn(void *file, void *buf, size_t len)
{
        int *fd = (int *)file;

        return sys_read(*fd, buf, len);
}

static ssize_t sys_write_fn(void *file, const void *buf, size_t len)
{
        int *fd = (int *)file;

        return sys_write(*fd, buf, len);
}

SMB_OFF_T transfer_file(int infd, int outfd, SMB_OFF_T n)
{
        return (SMB_OFF_T)transfer_file_internal(&infd, &outfd, (size_t)n,
                                                 sys_read_fn, sys_write_fn);
}