configure

#!/usr/bin/env bash
readonly CONFIG=.config.in
readonly TOP_PID=$$
readonly MISSING_LIB="Error: missing library dependency"
readonly MISSING_JANSSON="$MISSING_LIB libjansson (see www.digip.org/jansson)"
readonly MISSING_PCAP="$MISSING_LIB pcap (see www.tcpdump.org)"

trap "exit 1" TERM

error() {
    declare msg="$1"
    echo "$0: ${msg}."
    kill -s TERM $TOP_PID
}

supports_i386() {
    # Get gcc base settings
    declare cc_text="$(echo | (gcc -E -Wp,-v - > /dev/null) 2>&1)"

    # Extract include path
    declare prog="BEGIN { f=0 };
    /include <\.\.\.> search starts here:/ { f=1; next };
    /^End/ { f=0; next };
    f { print}"

    declare include_path="$(echo "$cc_text" | awk "$prog")"

    echo "supports_i386=false" > "$CONFIG"
    while read -r line; do
        # Check if 32bits compatibility bits are there
        if [ -e "$line/gnu/stubs-32.h" ]; then
            sed -i -E "s/(supports_i386=).*/\1true/" "$CONFIG"
            exit 0
        fi
    done <<< "$include_path"
    exit 1
}

missing_lib_version() {
    declare lib="$1"
    declare version="$2"
    error "Error: missing library version (${version} version of ${lib})"
}

assert_lib_present() {
    declare lib="$1"
    declare error_msg="$2"
    if ! /sbin/ldconfig -p | grep "$lib" >/dev/null 2>&1; then
        error "$error_msg"
    fi
}

assert_lib_version_present() {
    declare lib="$1"
    declare version="$2"
    if ! file $(readlink -f $(/sbin/ldconfig -p | grep "$lib" | awk '{print $NF}')) | grep "$version" >/dev/null; then
        missing_lib_version $lib $version
    fi
}

echo "[-] Checking presence of library dependencies..."
assert_lib_present "libjansson" "$MISSING_JANSSON"
assert_lib_present "libpcap" "$MISSING_PCAP"
echo "[-] Checking presence of 64-bit versions..."
assert_lib_version_present "libjansson" 64-bit
assert_lib_version_present "libpcap" 64-bit
if $(supports_i386); then
    echo "[-] Checking presence of 32-bit versions..."
    assert_lib_version_present "libjansson" 32-bit
    assert_lib_version_present "libpcap" 32-bit
else
    echo "[-] 32-bit support is disabled."
fi
echo "[-] Ok! Dependencies present."
echo "[-] Issue \"make && make install\" to compile & install tcpsnitch."