source: bootcd/isolinux/syslinux-6.03/com32/lib/sys/openmem.c

/* ----------------------------------------------------------------------- *
 *
 *   Copyright 2003-2008 H. Peter Anvin - All Rights Reserved
 *
 *   Permission is hereby granted, free of charge, to any person
 *   obtaining a copy of this software and associated documentation
 *   files (the "Software"), to deal in the Software without
 *   restriction, including without limitation the rights to use,
 *   copy, modify, merge, publish, distribute, sublicense, and/or
 *   sell copies of the Software, and to permit persons to whom
 *   the Software is furnished to do so, subject to the following
 *   conditions:
 *
 *   The above copyright notice and this permission notice shall
 *   be included in all copies or substantial portions of the Software.
 *
 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 *   OTHER DEALINGS IN THE SOFTWARE.
 *
 * ----------------------------------------------------------------------- */

#include <errno.h>
#include <com32.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include "file.h"

/*
 * openmem.c
 *
 * Open a chunk of memory as if it was a file
 */

const struct input_dev __file_dev;

int openmem(const void *base, size_t len, int flags)
{
    int fd;
    struct file_info *fp;

    fd = opendev(&__file_dev, NULL, flags);

    if (fd < 0)
        return -1;

    fp = &__file_info[fd];

    fp->i.fd.size  = fp->i.nbytes = len;
    fp->i.datap   = (void *)base;
    fp->i.fd.handle = 0;                /* No actual file */
    fp->i.offset  = 0;

    return fd;
}