GDB disassmbly helper

dism.sh

#!/bin/bash -eu

TOOLCHAIN=${TOOLCHAIN-arm-none-eabi-}
OBJDUMP=${TOOLCHAIN}objdump
GDB=${TOOLCHAIN}gdb

function usage()
{
    cat <<EOF
Usage: dism.sh -f|function -b|--binary --no-source

Disassmble a possibly mangled function and output to stdout. For C functions, just provide
the function name. For C++, either locate the mangled name yourself or provide a substring
and you'll get given a list of possible matches to chose from.

Optional arguments:
  -h, --help     Show this help message and exit.
  -f, --function Name of function to disassemble.
  -b, --binary   Target binary.
  --no-source    Do not emit source reference

ENV:
  TOOLCHAIN: toolchain prefix, default arm-none-eabi

Example:

  Disassemble a function named foo.
  dism.sh --funcion foo --binary my_binary

  Disassemble a function named foo using a different gdb
  TOOLCHAIN= dism.sh --funcion foo --binary my_binary
EOF
}

target_function=
binary=
dism_args="/s"

while [ ${#} -gt 0 ] ; do
  case "${1}" in
    -h|--help)
      usage
      exit 0
      ;;
    -f|--function)
      target_function="${2}"
      shift
      ;;
    -b|--binary)
      binary="${2}"
      shift
      ;;
    --no-source)
      dism_args=""
      ;;
    *)
      usage
      exit 2
      ;;
  esac
  shift
done

if [ -z "${target_function}" ]; then
    echo "--function required"
    usage
    exit 1
fi

if [ -z "${binary}" ]; then
    echo "--binary required"
    usage
    exit 1
fi

matched_functions=()
while IFS='' read -r func; do
    matched_functions+=("$func");
done < <(${OBJDUMP} -j .text -t "${binary}" \
            | grep "${target_function}" \
            | awk -F ' ' '{print $6}')

if [ "${#matched_functions[@]}" -eq 0 ]; then
    echo "Function not found"
    exit 1
elif [ "${#matched_functions[@]}" -gt 1 ]; then
    prompt="Multiple (mangled?) functions found. Pick one:"
    PS3="${prompt} "
    select func in "${matched_functions[@]}"; do
        matched_functions=("${func}")
        break
    done
fi

target_function=${matched_functions[0]}
$GDB -batch -ex "disassemble$dism_args $target_function" "${binary}"