FreeBSD/Linux Kernel Cross Reference
sys/tools/embed_mfs.sh

     #!/bin/sh
     #
     # Copyright (C) 2008 The FreeBSD Project. 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 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 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.
    #
    # $FreeBSD: releng/11.2/sys/tools/embed_mfs.sh 331691 2018-03-28 17:19:04Z emaste $ 
    #
    # Embed an MFS image into the kernel body or the loader body (expects space
    # reserved via MD_ROOT_SIZE (kernel) or MD_IMAGE_SIZE (loader))
    #
    # $1: kernel or loader filename
    # $2: MFS image filename
    #
    
    if [ $# -ne 2 ]; then
            echo "usage: $(basename $0) target mfs_image"
            exit 0
    fi
    if [ ! -w "$1" ]; then
            echo $1 not writable
            exit 1
    fi
    
    mfs_size=`stat -f '%z' $2 2> /dev/null`
    # If we can't determine MFS image size - bail.
    [ -z ${mfs_size} ] && echo "Can't determine MFS image size" && exit 1
    
    err_no_mfs="Can't locate mfs section within "
    
    if file -b $1 | grep -q '^ELF ..-bit .SB executable'; then
    
            sec_info=`elfdump -c $1 2> /dev/null | grep -A 5 -E "sh_name: oldmfs$"`
            # If we can't find the mfs section within the given kernel - bail.
            [ -z "${sec_info}" ] && echo "${err_no_mfs} $1" && exit 1
    
            sec_size=`echo "${sec_info}" | awk '/sh_size/ {print $2}' 2>/dev/null`
            sec_start=`echo "${sec_info}" | \
                awk '/sh_offset/ {print $2}' 2>/dev/null`
    
    else
    
            #try to find start byte of MFS start flag otherwise - bail.
            sec_start=`strings -at d $1 | grep "MFS Filesystem goes here"` || \
                { echo "${err_no_mfs} $1"; exit 1; }
            sec_start=`echo ${sec_start} | awk '{print $1}'`
    
            #try to find start byte of MFS end flag otherwise - bail.
            sec_end=`strings -at d $1 | \
                grep "MFS Filesystem had better STOP here"` || \
                { echo "${err_no_mfs} $1"; exit 1; }
            sec_end=`echo ${sec_end} | awk '{print $1}'`
    
            #calculate MFS section size
            sec_size=`expr ${sec_end} - ${sec_start}`
    
    fi
    
    # If the mfs section size is smaller than the mfs image - bail.
    [ ${sec_size} -lt ${mfs_size} ] && echo "MFS image too large" && exit 1
    
    # Dump the mfs image into the mfs section
    dd if=$2 ibs=8192 of=$1 obs=${sec_start} oseek=1 conv=notrunc 2> /dev/null && \
        echo "MFS image embedded into $1" && exit 0

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