Get bin info.py

This script helps you extract the data associated with a symbol in a binary. Remember that the output here will not necessarily be correctly ordered (see Endianness).

#!/bin/bash -eu
 
if [ -z ${CROSS_COMPILE+x} ]; then
    CROSS_COMPILE=""
fi
 
FILE=$1; shift
SYMBOL=$1; shift
 
if [ ! -e ${FILE} ]; then
    echo "File '${FILE}' does not exist..." >&2
    exit 1
fi
 
# get the symbol information
SYM_INFO=$(${CROSS_COMPILE}readelf ${FILE} --dyn-syms | grep "${SYMBOL}\$")
 
# get the offset of the symbol's data (in hex), rounded down to the closes 16-byte boundary
SYM_OFFSET_ALIGNED=$(echo "${SYM_INFO}" | awk '{v=strtonum("0x"$2); printf("0x%08X", v - (v % 16))}')
 
# get the offset of the symbol's data (in decomal), into this 16-byte aligned data
SYM_OFFSET_INTO_ALIGNED_DATA=$(echo "${SYM_INFO}" | awk '{v=strtonum("0x"$2); printf("%d", (v % 16) * 2)}')
 
# get the size of the symbol's data (in decimal), as nibbles / hex digits
SYM_SIZE_IN_NIBBLES=$(echo "${SYM_INFO}" | awk '{v=strtonum($3); printf "%d",v * 2}')
 
# get the number of 16-byte rows that this symbol spans
SYM_ROWS_SPANNED=$(echo "${SYM_INFO}" | awk '{v=strtonum($3); printf("%d", (v * 16) - 1)}')
 
# get the rows for the interesting region of the file
REGION_DATA=$(${CROSS_COMPILE}readelf ${FILE} --hex-dump .rodata | grep "${SYM_OFFSET_ALIGNED}" -A${SYM_ROWS_SPANNED} | cut -b14-48 | tr -d ' \n')
 
# snip out the symbol's data
DATA=$(echo -n "${REGION_DATA}" | cut -b $((SYM_OFFSET_INTO_ALIGNED_DATA + 1))-$((SYM_OFFSET_INTO_ALIGNED_DATA + SYM_SIZE_IN_NIBBLES)))
 
# print out the symbol's data...
## ... as hex digits
#echo ${DATA}
## ... as raw binary data
echo -n ${DATA} | sed -e "s/.\{2\}/&\n/g" | awk -b '{printf "%c", strtonum("0x"$0)}'
## ... rendered by hexdump
#echo -n ${DATA} | sed -e "s/.\{2\}/&\n/g" | awk -b '{printf "%c", strtonum("0x"$0)}' | hexdump -C