#!/bin/bash
#
#                              Copyright (C) 2015 by Rafael Santiago
#
# This is free software. You can redistribute it and/or modify under
# the terms of the GNU General Public License version 2.
#
# "snail.sh"
#       by Rafael Santiago
#
# Description: a simple script which scans ELF dependencies.
#

SNAIL_TEMP_DIR=".snail"

SNAIL_LD_32=""

SNAIL_LD_64=""

SHOULD_REMOVE_INTERP=0

INTERP_PATH=""

function snail_find_app_deps() {
    temp_interp=$(setup_interp $1)
    printf "\t\t@@@ - Inspecting %s's dependencies...\n" $1
    for libpath in $(LD_TRACE_LOADED_OBJECTS=1 $1 | grep ".*/" | sed s/.*=\>// | sed s/\(.*//)
    do
    filename=$(basename ${libpath})
    file_exists=$(ls -1 ${SNAIL_TEMP_DIR}/${filename} 2>/dev/null | wc -l)
    if [ ${file_exists} -eq 0 ] ; then
        printf "\t\t\t@@@ - copying: %s... " ${filename}
            cp ${libpath} ${SNAIL_TEMP_DIR}/ &>/dev/null
            if [ $? -eq 0 ] ; then
            printf "copied.\n"
            else
            printf "copy error... aborting.\n"
            fini_snail
            exit 1
            fi
        else
            printf "\t\t\t@@@ - already copied: %s.\n" ${filename}
    fi
    done
    if [ ! -z "$temp_interp" ] ; then
        remove_interp $temp_interp
    fi
    printf "\t\t@@@ - done.\n"
}

function snail_find_so_deps() {
    temp_interp=$(setup_interp $1)
    ld_so=${SNAIL_LD_32}
    if [ $(get_platform_arch) -eq 64 ] ; then
        ld_so=${SNAIL_LD_64}
    fi
    printf "\t\t@@@ - Inspecting %s's dependencies...\n" $1
    for libpath in $(LD_TRACE_LOADED_OBJECTS=1 ${ld_so} ./$1 | grep ".*/" | sed s/.*=\>// | sed s/\(.*//)
    do
        filename=$(basename ${libpath})
        file_exists=$(ls -1 ${SNAIL_TEMP_DIR}/${filename} 2>/dev/null | wc -l)
        if [ ${file_exists} -eq 0 ] ; then
            printf "\t\t\t@@@ - copying: %s... " ${filename}
            cp ${libpath} ${SNAIL_TEMP_DIR}/ &>/dev/null
            if [ $? -eq 0 ] ; then
                printf "copied.\n"
            else
                printf "copy error... aborting.\n"
                fini_snail
                exit 1
            fi
        else
            printf "\t\t\t@@@ - already copied: %s.\n" ${filename}
        fi
    done
    printf "\t\t@@@ - done.\n"
    filename=$(basename ${ld_so})
    file_exists=$(ls -1 ${SNAIL_TEMP_DIR}/${filename} 2>/dev/null | wc -l)
    if [ ${file_exists} -eq 0 ] ; then
        printf "\t\t@@@ - copying: %s... " ${filename}
        if [ $? -eq 0 ] ; then
            printf "copied.\n"
        else
            printf "copy error... aborting.\n"
            fini_snail
            exit 1
        fi
    fi
    if [ ! -z "$temp_interp" ] ; then
        remove_interp $temp_interp
    fi
}

function is_a_so() {
    retval=0
    if [ $(file $1 | grep ".*: ELF.*shared object," | wc -l) -eq 1 ] ; then
        retval=1
    fi
    echo ${retval}
}

function get_elf_arch() {
    retval=32
    if [ $(file $1 | grep ".*: ELF 64-bit" | wc -l) -eq 1 ] ; then
        retval=64
    fi
    echo ${retval}
}

LIB_SEARCH_LOCATIONS="/lib /lib32 /lib64"
function find_ld_linux32() {
    SNAIL_LD_32=$(find ${LIB_SEARCH_LOCATIONS} -name "ld-linux.so.2" -executable 2>/dev/null | tail -1)
}

function find_ld_linux64() {
    SNAIL_LD_64=$(find ${LIB_SEARCH_LOCATIONS} -name "ld-linux-x86-64.so.2" -executable 2>/dev/null | tail -1)
}

function get_platform_arch() {
    retval=32
    if [ $(uname -a | grep ".*x86_64" | wc -l) -eq 1 ] ; then
        retval=64
    fi
    echo ${retval}
}

function init_snail() {
    rm -rf ${SNAIL_TEMP_DIR}
    mkdir ${SNAIL_TEMP_DIR}
    find_ld_linux32
    if [ $(get_platform_arch) -eq 64 ] ; then
        find_ld_linux64
    fi
}

function setup_interp() {
    interpreter=""
    filename=$1
    if [ $(file ${filename} | grep ".*: ELF" | wc -l) -eq 1 ] ; then
        if [ $(is_a_so ${filename}) -ne 1 ] ; then
            interpreter=$(readelf -l ${filename} | grep "\\[.*:.*\\]" | sed s/.*\\[// | sed s/.*:// | sed s/\\].*//)
        fi
    fi

    if [ ! -z ${interpreter} ] ; then
        if [ ! -f ${interpreter} ] ; then
            mkdir -p $(dirname ${interpreter})
            if [ $(get_platform_arch) -eq 32 ] ; then
                cp ${SNAIL_LD_32} ${interpreter} &>/dev/null
            else
                cp ${SNAIL_LD_64} ${interpreter} &>/dev/null
            fi
            echo ${interpreter}
        fi
    fi
}

function remove_interp() {
    if [ -f $1 ]; then
        printf "\t\t\t@@@ - removing temporary interpreter $1\n"
        rm $1 &>/dev/null
        rmdir $(dirname $1) &>/dev/null
    fi
}

function fini_snail() {
    rm -rf ${SNAIL_TEMP_DIR}
}

function zip_deps() {
    printf "@@@ - Zipping all collected dependencies into %s... " $1
    rm $1 &>/dev/null
    zip -j $1 ${SNAIL_TEMP_DIR}/* &>/dev/null
    if [ $? -eq 0 ] ; then
        printf "ok.\n"
    else
        printf "zip error... aborting.\n"
        fini_snail
        exit 1
    fi
    printf "@@@ - done.\n"
}

function snail() {
    printf "@@@@@@@@@@@@@@@@@@@@@\n"
    printf "@@@ - S n a i l - @@@\n"
    printf "@@@@@@@@@@@@@@@@@@@@@\n\n"
    printf "@@@ - Initialising...\n"
    init_snail $1
    printf "@@@ - done.\n\n"
    printf "@@@ - Now, looking for ELFs in directory %s...\n" $1
    for filename in $(find $1 -executable -type f -print)
    do
        if [ $(file ${filename} | grep ".*: ELF" | wc -l) -eq 1 ] ; then
            if [ $(is_a_so ${filename}) -eq 1 ] ; then
                printf "\t@@@ - Shared object: %s\n" ${filename}
                snail_find_so_deps ${filename}
            else
                printf "\t@@@ - Executable found: %s\n" ${filename}
                snail_find_app_deps ${filename}
            fi
        fi
    done
    printf "@@@ - done.\n"
    zip_deps $2
    fini_snail

}

# main() {

directory=""
output=""

while test -n "$1"
do
    case "$1" in
        -d | --directory)
            shift
            directory="$1"
            ;;

        -o | --output)
            shift
            output="$1"
            ;;

        -h | --help)
            printf "use: $0 --directory <directory containing your binaries> --output <output file path>\n"
            exit 1
            ;;
    esac
    shift
done

if [ -z ${directory} ] ; then
    printf "error: --directory option is missing.\n"
    exit 1
fi

if [ -z ${output} ] ; then
    printf "error: --output option is missing.\n"
    exit 1
fi

snail ${directory} ${output}

# }