install-jdk

#!/usr/bin/env bash

# $1?: A JVM directory or a directory containing a compressed JDK. Defaults to
#      the current directory
#
# Attempts to install a JDK to /usr/lib/jvm.
#
# This script will extract compressed JDK files and install them in
# /usr/lib/jvm. If the given directory is an already extracted JDK, it will be
# moved to /usr/lib/jvm. update-alternatives will be generated for the new JDK.
#
# If $1 is already in /usr/lib/jvm, only update-alternatives will be created.

if [[ $(id -u) -ne 0 ]]; then
    echo "This script needs to be run as root."
    exec sudo "PATH=$PATH" -k bash -$- "$0" "$@"

    # Exec shouldn't return, but just in case.
    exit $?
fi

############################
#  BEGIN HELPER FUNCTIONS  #
############################

# $1: jdk_dir
# $2: command name
_find_command() {
    for dir in bin jre/bin jre/lib; do
        file="$1/$dir/$2"
        if [ -x "$file" ]; then
            echo "$file"
            return 0
        fi
    done

    return 1
}

_is_jdk_dir() {
    [ -d "$1" ] && [ -d "${1}/bin" ] &&\
        _find_command "$1" java &>/dev/null &&\
        _find_command "$1" javac &>/dev/null
}

# $1 must pass _is_jdk_dir
_get_version() {
    local java
    java=$(_find_command "$1" java)

    $java -version |& sed -nre 's/(openjdk|java) version "(.+)".*/\2/p'
}

# $1 version number
# 1.8.0      -> 800000
# 1.8.0_56   -> 800056
# 1.8.0_121  -> 800121
# 1.8.0_1000 -> 800999
# 9          -> 900000
# 9.0.4      -> 900004
_get_priority() {
    local major minor security

    # Determine the major version.
    if [[ $1 =~ ^1\..*$ ]]; then
        # Old-style version string (1.8.0_123).
        local IFS='.'
        local split=( $1 )
        unset IFS

        major=${split[1]}

        local IFS='_'
        split=( ${split[2]} )
        unset IFS

        minor=${split[0]}
        security=${split[1]}
    else
        # New-style JEP223 version string (9.0.4).
        local IFS='.'
        local split=( $1 )
        unset IFS

        major=${split[0]}
        minor=${split[1]}
        security=${split[2]}
    fi

    if [[ ${#minor} -gt 2 ]]; then
        minor=99
    else
        minor=$(printf "%02d" "$minor")
    fi

    if [[ ${#security} -gt 3 ]]; then
        security=999
    else
        security=$(printf "%03d" "$security")
    fi

    echo "${major}${minor}${security}"
}


# Report which line of the file caused the error.
_report_error() {
    echo "Error occurred on line ${BASH_LINENO} of ${BASH_SOURCE}:" >&2
    sed -ne "${BASH_LINENO}p" "${BASH_SOURCE}" >&2
}

# Clean up temp files.
_cleanup() {
    if [ -n "$extract_to" ]; then
        rm -rf "$extract_to"
    fi
}

##########################
#  END HELPER FUNCTIONS  #
##########################

set -e -o pipefail
trap _report_error ERR

# Clean up temp files on exiting.
trap _cleanup EXIT

jdk_dir=$(realpath "${1:-$(pwd)}")

if ! _is_jdk_dir "$jdk_dir"; then
    if [ -d "$jdk_dir" ]; then
        echo "Looking for compressed JDK in $jdk_dir"

        files=()
        for file in "$jdk_dir"/*jdk*; do
            [ -f "$file" ] && files+=( "$file" )
        done

        if [ ${#files[@]} -eq 0 ]; then
            echo "Could not find a compressed JDK file."
            exit 1
        elif [ ${#files[@]} -eq 1 ]; then
            file_to_install=${files[0]}
            echo "Found: $file_to_install"
        else
            echo "Please select one of the following."
            select file_to_install in "${files[@]}"; do
                echo "Selected: $file_to_install"
                break
            done
        fi
    elif [ -f "$jdk_dir" ]; then
        file_to_install="$jdk_dir"
    else
        echo "Unknown parameter $jdk_dir"
        exit 1
    fi

    extract_to=$(mktemp -d)
    case "$file_to_install" in
        *.tar.gz)
            pv -N "Extracting" "$file_to_install" | tar -xzf - -C "$extract_to"
            ;;
        *)
            echo "I don't know how to extract $file_to_install"
            exit 1
            ;;
    esac

    children=( $(find "$extract_to" -mindepth 1 -maxdepth 1) )
    if [[ ${#children[@]} -eq 1 ]]; then
        jdk_dir=${children[0]}
    else
        jdk_dir=$extract_to
    fi

    if ! _is_jdk_dir "$jdk_dir"; then
        echo "$file_to_install was not a JDK."
        exit 1
    fi
fi

if [[ $jdk_dir = /usr/lib/jvm/* ]]; then
    version=$(_get_version "$jdk_dir")
else
    version=$(_get_version "$jdk_dir")
    jdk_name="jdk${version}"
    new_location=/usr/lib/jvm/$jdk_name
    if [ -e "$new_location" ]; then
        echo "$new_location already exists!"
        exit 1
    fi

    parent=$(dirname "$new_location")
    mkdir -p "$parent"
    mv "$jdk_dir" "$new_location"
    jdk_dir=$new_location
    chown -R root:root "$jdk_dir"
fi

slave_commands=( appletviewer extcheck idlj jar jarsigner java javac javadoc \
javah javap jcmd jconsole jdb jexec jhat jinfo jps jrunscript jsadebugd \
jshell jstack jstat jstatd keytool native2ascii orbd pack200 policytool \
rmic rmid rmiregistry schemagen serialver servertool tnameserv unpack200 wsgen \
wsimport xjc )

priority=$(_get_priority "$version")
command="--install /usr/lib/jvm/default-java default-java"
command+=" \"$jdk_dir\" $priority"

for cmd in "${slave_commands[@]}"; do
    echo "Updating $cmd"
    path=$(_find_command "$jdk_dir" "$cmd" || echo)
    if [ -n "$path" ]; then
        # If it was previously set up as a master link, remove all entries.
        update-alternatives --remove-all $cmd &>/dev/null || true
        command+=" --slave /usr/bin/$cmd $cmd \"$path\""
    else
        echo "Could not find $cmd"
    fi
done

eval update-alternatives $command