freebsd-dev/sys/boot/common/md.c
Marcel Moolenaar 066b1a5c7b Add support for memory disk (md). The size of the memory disk
is determined by MD_IMAGE_SIZE. A file system can be embedded
into the loader with /sys/tools/embed_mfs.sh.
Note that md.c is not included when MD_IMAGE_SIZE is not set.
2009-12-13 01:20:32 +00:00

152 lines
3.5 KiB
C

/*-
* Copyright (c) 2009 Marcel Moolenaar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/endian.h>
#include <sys/queue.h>
#include <machine/stdarg.h>
#include <stand.h>
#include "bootstrap.h"
#define MD_BLOCK_SIZE 512
#ifndef MD_IMAGE_SIZE
#error Must be compiled with MD_IMAGE_SIZE defined
#endif
#if (MD_IMAGE_SIZE == 0 || MD_IMAGE_SIZE % MD_BLOCK_SIZE)
#error Image size must be a multiple of 512.
#endif
/*
* Preloaded image gets put here.
* Applications that patch the object with the image can determine
* the size looking at the start and end markers (strings),
* so we want them contiguous.
*/
static struct {
u_char start[MD_IMAGE_SIZE];
u_char end[128];
} md_image = {
.start = "MFS Filesystem goes here",
.end = "MFS Filesystem had better STOP here",
};
/* devsw I/F */
static int md_init(void);
static int md_strategy(void *, int, daddr_t, size_t, char *, size_t *);
static int md_open(struct open_file *, ...);
static int md_close(struct open_file *);
static void md_print(int);
struct devsw md_dev = {
"md",
DEVT_DISK,
md_init,
md_strategy,
md_open,
md_close,
noioctl,
md_print
};
static int
md_init(void)
{
return (0);
}
static int
md_strategy(void *devdata, int rw, daddr_t blk, size_t size, char *buf,
size_t *rsize)
{
struct devdesc *dev = (struct devdesc *)devdata;
size_t ofs;
if (dev->d_unit != 0)
return (ENXIO);
if (blk < 0 || blk >= (MD_IMAGE_SIZE / MD_BLOCK_SIZE))
return (EIO);
if (size % MD_BLOCK_SIZE)
return (EIO);
ofs = blk * MD_BLOCK_SIZE;
if ((ofs + size) > MD_IMAGE_SIZE)
size = MD_IMAGE_SIZE - ofs;
if (rsize != 0)
*rsize = size;
switch (rw) {
case F_READ:
bcopy(md_image.start + ofs, buf, size);
return (0);
case F_WRITE:
bcopy(buf, md_image.start + ofs, size);
return (0);
}
return (ENODEV);
}
static int
md_open(struct open_file *f, ...)
{
va_list ap;
struct devdesc *dev;
va_start(ap, f);
dev = va_arg(ap, struct devdesc *);
va_end(ap);
if (dev->d_unit != 0)
return (ENXIO);
return (0);
}
static int
md_close(struct open_file *f)
{
struct devdesc *dev;
dev = (struct devdesc *)(f->f_devdata);
return ((dev->d_unit != 0) ? ENXIO : 0);
}
static void
md_print(int verbose)
{
printf("MD (%u bytes)\n", MD_IMAGE_SIZE);
}