#!/bin/bash -e
# This is a mockup of a script to produce a snakeoil cert
# The aim is to have a debconfisable ssl-certificate script

. /usr/share/debconf/confmodule
db_version 2.0
db_capb backup

ask_via_debconf() {
    RET=""
    if db_settitle make-ssl-cert/title ; then
	: # OK
    else
	echo Debconf failed with error code $? $RET >&2
	echo Maybe your debconf database is corrupt. >&2
	echo Try re-installing ssl-cert. >&2
    fi

    RET=""
    while [ "x$RET" = "x" ]; do
	db_fset make-ssl-cert/hostname seen false
	db_input high make-ssl-cert/hostname || true
	db_go
	db_get make-ssl-cert/hostname
    done
    
    db_get make-ssl-cert/hostname
    HostName="$RET"
    db_fset make-ssl-cert/hostname seen false

    db_fset make-ssl-cert/altname seen false
    db_input high make-ssl-cert/altname || true
    db_go
    db_get make-ssl-cert/altname
    AddAltName="$RET"
    db_fset make-ssl-cert/altname seen false
    SubjectAltName="DNS:$HostName"
    [ -z "$AddAltName" ] || SubjectAltName="$SubjectAltName,$AddAltName"
}

make_snakeoil() {
    if ! HostName="$(hostname -f)" ; then
        HostName="$(hostname)"
        echo make-ssl-cert: Could not get FQDN, using \"$HostName\".
        echo make-ssl-cert: You may want to fix your /etc/hosts and/or DNS setup and run
        echo make-ssl-cert: 'make-ssl-cert generate-default-snakeoil --force-overwrite'
        echo make-ssl-cert: again.
    fi
    SubjectAltName="DNS:$HostName"
    if [ ${#HostName} -gt 64 ] ; then
        HostName="$(hostname)"
    fi
}

create_temporary_cnf() {
    sed -e s#@HostName@#"$HostName"# -e s#@SubjectAltName@#"$SubjectAltName"# $template > $TMPFILE
}

# Takes two arguments, the base layout and the output cert.

if [ $# -lt 2 ] && [ "$1" != "generate-default-snakeoil" ]; then
    printf "Usage: $0 template output [--force-overwrite]\n";
    printf "Usage: $0 generate-default-snakeoil [--force-overwrite]\n";
    exit 1;
fi

if [ "$1" != "generate-default-snakeoil" ]; then
    template="$1"
    output="$2"
    # be anal in manual mode.
    if [ ! -f $template ]; then
	printf "Could not open template file: $template!\n";
	exit 1;
    fi
    if [ -f $output ] && [ "$3" != "--force-overwrite" ]; then
        printf "$output file already exists!\n";
        exit 1;
    fi
    ask_via_debconf
else
    template="/usr/share/ssl-cert/ssleay.cnf"
    if [ -f "/etc/ssl/certs/ssl-cert-snakeoil.pem" ] && [ -f "/etc/ssl/private/ssl-cert-snakeoil.key" ]; then
        if [ "$2" != "--force-overwrite" ]; then
             exit 0
        fi
    fi
    make_snakeoil
fi

# # should be a less common char
# problem is that openssl virtually accepts everything and we need to
# sacrifice one char.

TMPFILE="$(mktemp)" || exit 1
TMPOUT="$(mktemp)"  || exit 1

trap "rm -f $TMPFILE $TMPOUT" EXIT

create_temporary_cnf

# create the certificate.

umask 077

if [ "$1" != "generate-default-snakeoil" ]; then
    if ! openssl req -config $TMPFILE -new -x509 -days 3650 -nodes -sha256 \
	-out $output -keyout $output > $TMPOUT 2>&1
    then
	echo Could not create certificate. Openssl output was: >&2
	cat $TMPOUT >&2
	exit 1
    fi
    chmod 600 $output
    # hash symlink
    cd $(dirname $output)
    ln -sf $(basename $output) $(openssl x509 -hash -noout -in $(basename $output))
else
    if ! openssl req -config $TMPFILE -new -x509 -days 3650 -nodes -sha256 \
	-out /etc/ssl/certs/ssl-cert-snakeoil.pem \
        -keyout /etc/ssl/private/ssl-cert-snakeoil.key > $TMPOUT 2>&1
    then
	echo Could not create certificate. Openssl output was: >&2
	cat $TMPOUT >&2
	exit 1
    fi
    chmod 644 /etc/ssl/certs/ssl-cert-snakeoil.pem
    chmod 640 /etc/ssl/private/ssl-cert-snakeoil.key
    chown root:ssl-cert /etc/ssl/private/ssl-cert-snakeoil.key
    # hash symlink
    cd /etc/ssl/certs/
    ln -sf ssl-cert-snakeoil.pem $(openssl x509 -hash -noout -in ssl-cert-snakeoil.pem)
fi