* zImage로부터 initramfs.cpio 추출하기
#!/bin/bash
# This is an update version of the script found at
# http://forum.xda-developers.com/wiki/index.php?title=Extract_initramfs_from_zImage
#
# The problem with that script is that the gzip magic number occasionally occur
# naturally, meaning that some non-compressed files get uncompressed.
DEBUG=
TEMP_DIR=/tmp
KERNEL_FILE=kernel
KERNEL_GZIP_FILE=kernel.gz
INITRAMFS_FILE=initramfs.cpio
INITRAMFS_DIR=initramfs_root
# DO NOT MODIFY BELOW THIS LINE
[ -z $1 ] && exit 1 || zImage=$1
[ ! -e $1 ] && exit 1
#GET CURRENT DIR
CURRENT_DIR=`pwd`
function pre_clean()
{
[ -z $DEBUG ] || echo "-D- Function: pre_clean()"
[ -e $INITRAMFS_FILE ] && ( [ -z $DEBUG ] || echo "-D- Deleting $INITRAMFS_FILE"; rm -f $INITRAMFS_FILE )
[ -e $INITRAMFS_DIR ] && ( [ -z $DEBUG ] || echo "-D- Deleting $INITRAMFS_DIR"; rm -rf $INITRAMFS_DIR )
[ -z $DEBUG ] || echo
}
function ungzip_kernel()
{
#========================================================
# find start of gziped kernel object in the zImage file:
#========================================================
[ -z $DEBUG ] || echo "-D- Function: ungzip_kernel()"
pos=`grep -P -a -b -m 1 --only-matching '\x1F\x8B\x08' $zImage | cut -f 1 -d :`
echo "-I- Extracting gzip'd kernel image from file: $zImage (start = $pos)"
if [ ! -z $pos ]; then
dd if=$zImage of=$TEMP_DIR/$KERNEL_GZIP_FILE bs=1 skip=$pos 2>/dev/null >/dev/null
gunzip -qf $TEMP_DIR/$KERNEL_GZIP_FILE
else
echo "-E- Compressed kernel image not found"; exit 1
fi
[ -z $DEBUG ] || echo
}
function search_cpio()
{
#========================================================
# Determine cpio compression type:
#========================================================
[ -z $DEBUG ] || echo "-D- Function: search_cpio()"
for x in gzip bzip lzma none; do
case $x in
bzip)
csig='\x{31}\x{41}\x{59}\x{26}\x{53}\x{59}'
ucmd='bunzip2 -q'
fext='.bz2'
;;
gzip)
csig='\x1F\x8B\x08'
ucmd='gunzip -q'
fext='.gz'
;;
lzma)
csig='\x{5D}\x{00}\x..\x{FF}\x{FF}\x{FF}\x{FF}\x{FF}\x{FF}'
ucmd='unlzma -q'
fext='.lzma'
;;
none)
csig='070701'
ucmd=
fext=
;;
esac
#========================================================================
# Search for compressed cpio archive
#========================================================================
search=`grep -P -a -b -m 1 --only-matching $csig $TEMP_DIR/$KERNEL_FILE | cut -f 1 -d : | head -1`
pos=${search:-0}
if [ ${pos} -gt 0 ]; then
if [ ${pos} -le ${cpio_compressed_start:-0} ] || [ -z $cpio_compressed_start ];then
cpio_compressed_start=$pos
compression_name=$x
compression_signature=$csig
uncompress_cmd=$ucmd
file_ext=$fext
[ -z $DEBUG ] || echo "-D- Checking for compression type: $compression_name | signature: $compression_signature | in file: $TEMP_DIR/$KERNEL_FILE | offset = $pos"
fi
fi
done
[ $compression_name = "bzip" ] && cpio_compressed_start=$((cpio_compressed_start - 4))
echo "-I- CPIO compression type detected = $compression_name | offset = $cpio_compressed_start"
[ -z $DEBUG ] || echo
}
function extract_cpio()
{
[ -z $DEBUG ] || echo "-D- Function: extract_cpio()"
if [ ! $compression_name = "none" ]; then
echo "-I- Extracting $compression_name'd compressed CPIO image from kernel image (offset = $cpio_compressed_start)"
[ -z $DEBUG ] || echo "-D- dd if=$TEMP_DIR/$KERNEL_FILE of=$TEMP_DIR/$INITRAMFS_FILE$file_ext bs=1 skip=$cpio_compressed_start; $uncompress_cmd $TEMP_DIR/$INITRAMFS_FILE$file_ext"
dd if=$TEMP_DIR/$KERNEL_FILE of=$TEMP_DIR/$INITRAMFS_FILE$file_ext bs=1 skip=$cpio_compressed_start 2>/dev/null >/dev/null
$uncompress_cmd -q $TEMP_DIR/$INITRAMFS_FILE$file_ext
else
echo "-I- Extracting non-compressed CPIO image from kernel image (offset = $cpio_compressed_start)"
[ -z $DEBUG ] || echo "-D- dd if=$TEMP_DIR/$KERNEL_FILE of=$TEMP_DIR/${INITRAMFS_FILE}${file_ext} bs=1 skip=$cpio_compressed_start 2>/dev/null >/dev/null"
dd if=$TEMP_DIR/$KERNEL_FILE of=$TEMP_DIR/${INITRAMFS_FILE}${file_ext} bs=1 skip=$cpio_compressed_start 2>/dev/null >/dev/null
fi
[ -z $DEBUG ] || echo
}
function uncompress_cpio()
{
#==========================================================================
# find start and end of the "cpio" initramfs image inside the kernel object:
# ASCII cpio header starts with '070701'
# The end of the cpio archive is marked with an empty file named TRAILER!!!
#==========================================================================
[ -z $DEBUG ] || echo "-D- Function: uncompress_cpio()"
if [ ! $compress_type = "none" ]; then
start=`grep -a -b -m 1 --only-matching '070701' $TEMP_DIR/$INITRAMFS_FILE | head -1 | cut -f 1 -d :`
end=`grep -a -b -m 1 --only-matching 'TRAILER!!!' $TEMP_DIR/$INITRAMFS_FILE | head -1 | cut -f 1 -d :`
if [ ! -z $start ] || [ ! -z $end ]; then
#11 bytes = length of TRAILER!!! zero terminated string, fixes premature end of file warning in CPIO
end=$((end + 14))
[ -z $DEBUG ] || echo "-D- Kernel start = $start"
[ -z $DEBUG ] || echo "-D- Kernel end = $end"
count=$((end - start))
if (($count < 0)); then
echo "-E- Couldn't match start/end of the initramfs image."
exit 1
fi
echo "-I- Extracting initramfs image from file: $inputfile (start = $start, end = $end)"
dd if=$TEMP_DIR/$INITRAMFS_FILE of=$CURRENT_DIR/$INITRAMFS_FILE bs=1 skip=$start count=$count 2>/dev/null >/dev/null
INITRAMFS_FILE=$CURRENT_DIR/$INITRAMFS_FILE
else
echo "-E- No CPIO image found in $inputfile."
fi
else
echo "-I- CPIO already uncompressed."
fi
[ -z $DEBUG ] || echo
}
function expand_cpio_archive()
{
[ -z $DEBUG ] || echo "-D- Function: expand_cpio_archive()"
echo "-I- Expanding CPIO archive: $INITRAMFS_FILE to $INITRAMFS_DIR."
if [ -e $TEMP_DIR/$INITRAMFS_FILE ]; then
mkdir $INITRAMFS_DIR
cd $INITRAMFS_DIR
cpio --quiet -i --make-directories --preserve-modification-time --no-absolute-filenames -F $TEMP_DIR/$INITRAMFS_FILE 2>/dev/null
fi
[ -z $DEBUG ] || echo
}
function clean_up()
{
[ -z $DEBUG ] || echo "-D- Deleting $TEMP_DIR/$KERNEL_FILE"; rm -f $TEMP_DIR/$KERNEL_FILE
[ -z $DEBUG ] || echo "-D- Deleting $TEMP_DIR/$INITRAMFS_FILE"; rm -f $TEMP_DIR/$INITRAMFS_FILE
[ -z $DEBUG ] || echo "-D- Deleting $TEMP_DIR/$INITRAMFS_FILE$file_ext"; rm -f $TEMP_DIR/$INITRAMFS_FILE$file_ext
}
reset
pre_clean
ungzip_kernel
search_cpio
extract_cpio
cp -p /tmp/initramfs.cpio ./
uncompress_cpio
expand_cpio_archive
clean_up