#!/bin/bash
#
# .---.                  .              .
# |                      |              |
# |--- .--. .-.  .-.  .-.|  .-. .--.--. |.-.  .-. .--.  .-.
# |    |   (.-' (.-' (   | (   )|  |  | |   )(   )|  | (.-'
# '    '     --'  --'  -' -  -' '  '   -' -'   -' '   -  --'
#
#                    Freedom in the Cloud
#
# Email functions
#
# License
# =======
#
# Copyright (C) 2014-2017 Bob Mottram <bob@freedombone.net>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# the default email address
MY_EMAIL_ADDRESS=$MY_USERNAME@$DEFAULT_DOMAIN_NAME

# If you want to run a public mailing list specify its name here.
# There should be no spaces in the name
PUBLIC_MAILING_LIST=
# Optional different domain name for the public mailing list
PUBLIC_MAILING_LIST_DOMAIN_NAME=
# Directory where the public mailing list data is stored
PUBLIC_MAILING_LIST_DIRECTORY="/var/spool/mlmmj"

# If you want to run an encrypted mailing list specify its name here.
# There should be no spaces in the name
PRIVATE_MAILING_LIST=

GPG_KEYSERVER="hkp://keys.gnupg.net"

# whether to encrypt all incoming email with your public key
GPG_ENCRYPT_STORED_EMAIL="yes"

# optionally you can provide your exported GPG key pair here
# Note that the private key file will be deleted after use
# If these are unspecified then a new GPG key will be created
MY_GPG_PUBLIC_KEY=
MY_GPG_PRIVATE_KEY=

# optionally specify your public key ID
MY_GPG_PUBLIC_KEY_ID=

EXIM_ONION_REPO="https://github.com/petterreinholdtsen/exim4-smtorp"

# automatic archiving of email
CLEANUP_MAILDIR_REPO="https://github.com/bashrc/cleanup-maildir"
CLEANUP_MAILDIR_COMMIT='33241d2e3861f901ba17f5c77ada007e1ec06a86'

# email encryption at rest
GPGIT_REPO="https://gitlab.com/mikecardwell/gpgit"
GPGIT_COMMIT='583dc76119f19420f8a33f606744faa7c8922738'

# refresh gpg keys every few hours
REFRESH_GPG_KEYS_HOURS=2

function email_create_template {
    if [ ! -d /etc/skel/log ]; then
        mkdir -m 700 /etc/skel/log
    fi
    if [ ! -d /etc/skel/Maildir ]; then
        mkdir -m 700 /etc/skel/.mutt
        mkdir -m 700 /etc/skel/Maildir
        mkdir -m 700 /etc/skel/Maildir/new
        mkdir -m 700 /etc/skel/Maildir/cur
        mkdir -m 700 /etc/skel/Maildir/Sent
        mkdir -m 700 /etc/skel/Maildir/Sent/tmp
        mkdir -m 700 /etc/skel/Maildir/Sent/cur
        mkdir -m 700 /etc/skel/Maildir/Sent/new
        mkdir -m 700 /etc/skel/Maildir/.learn-spam
        mkdir -m 700 /etc/skel/Maildir/.learn-spam/cur
        mkdir -m 700 /etc/skel/Maildir/.learn-spam/new
        mkdir -m 700 /etc/skel/Maildir/.learn-spam/tmp
        mkdir -m 700 /etc/skel/Maildir/.learn-ham
        mkdir -m 700 /etc/skel/Maildir/.learn-ham/cur
        mkdir -m 700 /etc/skel/Maildir/.learn-ham/new
        mkdir -m 700 /etc/skel/Maildir/.learn-ham/tmp
        ln -s /etc/skel/Maildir/.learn-spam /etc/skel/Maildir/spam
        ln -s /etc/skel/Maildir/.learn-ham /etc/skel/Maildir/ham
    fi

    if [ ! -d /home/$MY_USERNAME/Maildir ]; then
        mkdir -m 700 /home/$MY_USERNAME/.mutt
        mkdir -m 700 /home/$MY_USERNAME/Maildir
        mkdir -m 700 /home/$MY_USERNAME/Maildir/cur
        mkdir -m 700 /home/$MY_USERNAME/Maildir/tmp
        mkdir -m 700 /home/$MY_USERNAME/Maildir/new
        mkdir -m 700 /home/$MY_USERNAME/Maildir/Sent
        mkdir -m 700 /home/$MY_USERNAME/Maildir/Sent/cur
        mkdir -m 700 /home/$MY_USERNAME/Maildir/Sent/tmp
        mkdir -m 700 /home/$MY_USERNAME/Maildir/Sent/new
        mkdir -m 700 /home/$MY_USERNAME/Maildir/.learn-spam
        mkdir -m 700 /home/$MY_USERNAME/Maildir/.learn-spam/cur
        mkdir -m 700 /home/$MY_USERNAME/Maildir/.learn-spam/new
        mkdir -m 700 /home/$MY_USERNAME/Maildir/.learn-spam/tmp
        mkdir -m 700 /home/$MY_USERNAME/Maildir/.learn-ham
        mkdir -m 700 /home/$MY_USERNAME/Maildir/.learn-ham/cur
        mkdir -m 700 /home/$MY_USERNAME/Maildir/.learn-ham/new
        mkdir -m 700 /home/$MY_USERNAME/Maildir/.learn-ham/tmp
        ln -s /home/$MY_USERNAME/Maildir/.learn-spam /home/$MY_USERNAME/Maildir/spam
        ln -s /home/$MY_USERNAME/Maildir/.learn-ham /home/$MY_USERNAME/Maildir/ham
        chown -R $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/Maildir
    fi
}

function configure_email_onion {
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    if [[ $SYSTEM_TYPE == "mesh"* ]]; then
        return
    fi

    if ! grep -q "hidden_service_email" /etc/tor/torrc; then
        echo 'HiddenServiceDir /var/lib/tor/hidden_service_email/' >> /etc/tor/torrc
        echo 'HiddenServicePort 25 127.0.0.1:25' >> /etc/tor/torrc
        echo 'HiddenServicePort 587 127.0.0.1:587' >> /etc/tor/torrc
        echo 'HiddenServicePort 465 127.0.0.1:465' >> /etc/tor/torrc
    fi

    function_check onion_update
    onion_update

    function_check wait_for_onion_service
    wait_for_onion_service email

    if [ ! -f /var/lib/tor/hidden_service_email/hostname ]; then
        echo $"email onion site hostname not found"
        systemctl restart tor
        exit 782352
    fi

    onion_address=$(cat /var/lib/tor/hidden_service_email/hostname)
    set_completion_param "email onion domain" "${onion_address}"
    add_email_hostname "$onion_address"

    mark_completed $FUNCNAME
}

function check_email_address_exists {
    read_config_param ONION_ONLY
    read_config_param MY_USERNAME
    read_config_param DEFAULT_DOMAIN_NAME
    read_config_param MY_EMAIL_ADDRESS
    read_config_param DH_KEYLENGTH

    if [ ! $MY_USERNAME ]; then
        echo $'No username for email installation'
        exit 73672
    fi
    if [ ! $DEFAULT_DOMAIN_NAME ]; then
        echo $'No default domain name for email installation'
        exit 57634
    fi

    my_email="$MY_EMAIL_ADDRESS"
    if [ ${#my_email} -lt 3 ]; then
        MY_EMAIL_ADDRESS=${MY_USERNAME}@${DEFAULT_DOMAIN_NAME}
        write_config_param "MY_EMAIL_ADDRESS" "$MY_EMAIL_ADDRESS"
    fi
}

function backup_email {
    echo ''
}

function configure_firewall_for_email {
    if [[ $INSTALLED_WITHIN_DOCKER == "yes" ]]; then
        # docker does its own firewalling
        return
    fi
    if [[ $ONION_ONLY != "no" ]]; then
        return
    fi

    firewall_add Email 25 tcp
    firewall_add Email 587 tcp
    firewall_add Email 465 tcp
    firewall_add Imap 993 tcp
}

function encrypt_incoming_email {
    # encrypts incoming mail using your GPG public key
    # so even if an attacker gains access to the data at rest they still need
    # to know your GPG key password to be able to read anything
    if [ ! -d /etc/exim4 ]; then
        return
    fi

    # update to the next commit
    function_check set_repo_commit
    set_repo_commit $INSTALL_DIR/gpgit "gpgit commit" "$GPGIT_COMMIT" $GPGIT_REPO

    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi

    if [[ $GPG_ENCRYPT_STORED_EMAIL != "yes" ]]; then
        return
    fi

    if [ ! -f /usr/bin/gpgit.pl ]; then
        apt-get -yq install git libmail-gnupg-perl
        cd $INSTALL_DIR
        function_check git_clone
        git_clone $GPGIT_REPO $INSTALL_DIR/gpgit
        cd $INSTALL_DIR/gpgit
        git checkout $GPGIT_COMMIT -b $GPGIT_COMMIT
        set_completion_param "gpgit commit" "$GPGIT_COMMIT"
        cp gpgit.pl /usr/bin
    fi

    # add a procmail rule
    if ! grep -q "/usr/bin/gpgit.pl" /home/$MY_USERNAME/.procmailrc; then
        echo '' >> /home/$MY_USERNAME/.procmailrc
        echo ':0 f' >> /home/$MY_USERNAME/.procmailrc
        echo "| /usr/bin/gpgit.pl --encrypt-mode prefer-inline --inline-flatten $MY_EMAIL_ADDRESS" >> /home/$MY_USERNAME/.procmailrc
        chown $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/.procmailrc
        echo '' >> /etc/skel/.procmailrc
        echo ':0 f' >> /etc/skel/.procmailrc
        echo -n '| /usr/bin/gpgit.pl --encrypt-mode prefer-inline --inline-flatten $USER@' >> /etc/skel/.procmailrc
        echo "$DEFAULT_DOMAIN_NAME" >> /etc/skel/.procmailrc
    fi
    mark_completed $FUNCNAME
}

function encrypt_outgoing_email {
    # encrypts outgoing mail using your GPG public key
    # so even if an attacker gains access to the data at rest they still need
    # to know your GPG key password to be able to read sent mail
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    if [[ $GPG_ENCRYPT_STORED_EMAIL != "yes" ]]; then
        return
    fi

    if [ ! -d /home/$MY_USERNAME/.gnupg ]; then
        return
    fi

    if [ ! -f /home/$MY_USERNAME/.muttrc ]; then
        return
    fi

    # obtain your public key ID
    if [ ! $MY_GPG_PUBLIC_KEY_ID ]; then
        MY_GPG_PUBLIC_KEY_ID=$(gpg_pubkey_from_email "$MY_USERNAME" "$MY_EMAIL_ADDRESS")
        if [ ! "$MY_GPG_PUBLIC_KEY_ID" ]; then
            return
        fi
        if [ ${#MY_GPG_PUBLIC_KEY_ID} -lt 4 ]; then
            return
        fi
    fi

    if ! grep -q "pgp_encrypt_only_command" /home/$MY_USERNAME/.muttrc; then
        echo '' >> /home/$MY_USERNAME/.muttrc
        echo $'# Encrypt items in the Sent folder' >> /home/$MY_USERNAME/.muttrc
        echo "set pgp_encrypt_only_command=\"/usr/lib/mutt/pgpewrap gpg --batch --quiet --no-verbose --output - --encrypt --textmode --armor --trust-model always --encrypt-to $MY_GPG_PUBLIC_KEY_ID -- -r %r -- %f\"" >> /home/$MY_USERNAME/.muttrc
    else
        sed -i "s|set pgp_encrypt_only_command.*|set pgp_encrypt_only_command=\"/usr/lib/mutt/pgpewrap gpg --batch --quiet --no-verbose --output - --encrypt --textmode --armor --trust-model always --encrypt-to $MY_GPG_PUBLIC_KEY_ID -- -r %r -- %f\"|g" /home/$MY_USERNAME/.muttrc
    fi

    if ! grep -q "pgp_encrypt_sign_command" /home/$MY_USERNAME/.muttrc; then
        echo "set pgp_encrypt_sign_command=\"/usr/lib/mutt/pgpewrap gpg %?p?--passphrase-fd 0? --batch --quiet --no-verbose --textmode --output - --encrypt --sign %?a?-u %a? --armor --trust-model always --encrypt-to $MY_GPG_PUBLIC_KEY_ID -- -r %r -- %f\"" >> /home/$MY_USERNAME/.muttrc
    else
        sed -i "s|set pgp_encrypt_sign_command.*|set pgp_encrypt_sign_command=\"/usr/lib/mutt/pgpewrap gpg %?p?--passphrase-fd 0? --batch --quiet --no-verbose --textmode --output - --encrypt --sign %?a?-u %a? --armor --trust-model always --encrypt-to $MY_GPG_PUBLIC_KEY_ID -- -r %r -- %f\"|g" /home/$MY_USERNAME/.muttrc
    fi

    mark_completed $FUNCNAME
}

function encrypt_all_email {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $GPG_ENCRYPT_STORED_EMAIL != "yes" ]]; then
        return
    fi

    if [ -f /usr/local/bin/${PROJECT_NAME}-encrypt-mail ]; then
        if [ ! -f /usr/bin/encmaildir ]; then
            cp /usr/local/bin/${PROJECT_NAME}-encrypt-mail /usr/bin/encmaildir
        else
            HASH1=$(sha256sum /usr/local/bin/${PROJECT_NAME}-encrypt-mail | awk -F ' ' '{print $1}')
            HASH2=$(sha256sum /usr/bin/encmaildir | awk -F ' ' '{print $1}')
            if [[ "$HASH1" != "$HASH2" ]]; then
                cp /usr/local/bin/${PROJECT_NAME}-encrypt-mail /usr/bin/encmaildir
            fi
        fi
    else
        if [ ! -f /usr/bin/encmaildir ]; then
            cp /usr/bin/${PROJECT_NAME}-encrypt-mail /usr/bin/encmaildir
        else
            HASH1=$(sha256sum /usr/bin/${PROJECT_NAME}-encrypt-mail | awk -F ' ' '{print $1}')
            HASH2=$(sha256sum /usr/bin/encmaildir | awk -F ' ' '{print $1}')
            if [[ "$HASH1" != "$HASH2" ]]; then
                cp /usr/bin/${PROJECT_NAME}-encrypt-mail /usr/bin/encmaildir
            fi
        fi
    fi

    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi

    if [ ! /home/$MY_USERNAME/README ]; then
        touch /home/$MY_USERNAME/README
    fi
    if ! grep -q $"If you have imported legacy email which is not encrypted" /home/$MY_USERNAME/README; then
        echo '' >> /home/$MY_USERNAME/README
        echo '' >> /home/$MY_USERNAME/README
        echo $'# Encrypting legacy email' >> /home/$MY_USERNAME/README
        echo $'If you have imported legacy email which is not encrypted' >> /home/$MY_USERNAME/README
        echo $'then it can be encrypted with the command:' >> /home/$MY_USERNAME/README
        echo '' >> /home/$MY_USERNAME/README
        echo '  encmaildir' >> /home/$MY_USERNAME/README
        echo '' >> /home/$MY_USERNAME/README
        echo $'But be warned that depending upon how much email you have' >> /home/$MY_USERNAME/README
        echo $'this could take a seriously LONG time on the Beaglebone' >> /home/$MY_USERNAME/README
        echo $'and may be better done on a faster machine.' >> /home/$MY_USERNAME/README
        chown $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/README
        chmod 600 /home/$MY_USERNAME/README
    fi

    mark_completed $FUNCNAME
}

function email_client {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    apt-get -yq install lynx abook urlview mutt

    if [ ! -f /etc/Muttrc ]; then
        echo $"ERROR: Mutt does not appear to have installed. $CHECK_MESSAGE"
        exit 49
    fi

    if [ ! -d /home/$MY_USERNAME/.mutt ]; then
        mkdir /home/$MY_USERNAME/.mutt
    fi
    echo "text/html; lynx -dump -width=78 -nolist %s | sed ‘s/^ //’; copiousoutput; needsterminal; nametemplate=%s.html" > /home/$MY_USERNAME/.mutt/mailcap
    cp /home/$MY_USERNAME/.mutt/mailcap /etc/skel/.mutt
    chown -R $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/.mutt
    chown -R root:root /etc/skel/.mutt

    echo 'set mbox_type=Maildir' >> /etc/Muttrc
    echo 'set folder="~/Maildir"' >> /etc/Muttrc
    echo 'set mask="!^\\.[^.]"' >> /etc/Muttrc
    echo 'set mbox="~/Maildir"' >> /etc/Muttrc
    echo 'set record="+Sent"' >> /etc/Muttrc
    echo 'set postponed="+Drafts"' >> /etc/Muttrc
    echo 'set trash="+Trash"' >> /etc/Muttrc
    echo 'set spoolfile="~/Maildir"' >> /etc/Muttrc
    echo 'auto_view text/x-vcard text/html text/enriched' >> /etc/Muttrc
    echo 'set header_cache="+.cache"' >> /etc/Muttrc
    echo 'set markers=no' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# ctrl-u to view long URLs' >> /etc/Muttrc
    echo 'macro pager \cu <pipe-entry>"urlview"<enter> "Follow links with urlview"' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo 'macro index S "<tag-prefix><decode-save>=.learn-spam<enter>" "move to learn-spam"' >> /etc/Muttrc
    echo 'macro pager S "<decode-save>=.learn-spam<enter>" "move to learn-spam"' >> /etc/Muttrc
    echo 'macro index H "<tag-prefix><decode-copy>=.learn-ham<enter>" "copy to learn-ham"' >> /etc/Muttrc
    echo 'macro pager H "<decode-copy>=.learn-ham<enter>" "copy to learn-ham"' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# set up the sidebar' >> /etc/Muttrc
    echo 'set sidebar_width=22' >> /etc/Muttrc
    echo 'set sidebar_visible=yes' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo 'set rfc2047_parameters' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# Show inbox and sent items' >> /etc/Muttrc
    echo 'mailboxes = =admin =Sent =maybe-spam =spam' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# Alter these colours as needed for maximum bling' >> /etc/Muttrc
    echo 'color sidebar_new yellow default' >> /etc/Muttrc
    echo 'color normal white default' >> /etc/Muttrc
    echo 'color hdrdefault brightcyan default' >> /etc/Muttrc
    echo 'color signature green default' >> /etc/Muttrc
    echo 'color attachment brightyellow default' >> /etc/Muttrc
    echo 'color quoted green default' >> /etc/Muttrc
    echo 'color quoted1 white default' >> /etc/Muttrc
    echo 'color tilde blue default' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# ctrl-n, ctrl-p to select next, prev folder' >> /etc/Muttrc
    echo '# ctrl-o to open selected folder' >> /etc/Muttrc
    echo 'bind index \Cp sidebar-prev' >> /etc/Muttrc
    echo 'bind index \Cn sidebar-next' >> /etc/Muttrc
    echo 'bind index \Co sidebar-open' >> /etc/Muttrc
    echo 'bind pager \Cp sidebar-prev' >> /etc/Muttrc
    echo 'bind pager \Cn sidebar-next' >> /etc/Muttrc
    echo 'bind pager \Co sidebar-open' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# ctrl-b toggles sidebar visibility' >> /etc/Muttrc
    echo "macro index,pager \Cb '<enter-command>toggle sidebar_visible<enter><redraw-screen>' 'toggle sidebar'" >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# esc-m Mark new messages as read' >> /etc/Muttrc
    echo 'macro index <esc>m "T~N<enter>;WNT~O<enter>;WO\CT~T<enter>" "mark all messages read"' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# Collapsing threads' >> /etc/Muttrc
    echo 'macro index [ "<collapse-thread>" "collapse/uncollapse thread"' >> /etc/Muttrc
    echo 'macro index ] "<collapse-all>"    "collapse/uncollapse all threads"' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# threads containing new messages' >> /etc/Muttrc
    echo 'uncolor index "~(~N)"' >> /etc/Muttrc
    echo 'color index brightblue default "~(~N)"' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# new messages themselves' >> /etc/Muttrc
    echo 'uncolor index "~N"' >> /etc/Muttrc
    echo 'color index brightyellow default "~N"' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# GPG/PGP integration' >> /etc/Muttrc
    echo '# this set the number of seconds to keep in memory the passphrase used to encrypt/sign' >> /etc/Muttrc
    echo 'set pgp_timeout=1800' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# automatically sign and encrypt with PGP/MIME' >> /etc/Muttrc
    echo 'set pgp_autosign         # autosign all outgoing mails' >> /etc/Muttrc
    echo 'set pgp_autoencrypt      # Try to encrypt automatically' >> /etc/Muttrc
    echo 'set pgp_replyencrypt     # autocrypt replies to crypted' >> /etc/Muttrc
    echo 'set pgp_replysign        # autosign replies to signed' >> /etc/Muttrc
    echo 'set pgp_auto_decode=yes  # decode attachments' >> /etc/Muttrc
    echo 'set fcc_clear=no         # Keep encrypted copy of sent encrypted mail' >> /etc/Muttrc
    echo 'unset smime_is_default' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo 'set alias_file=~/.mutt-alias' >> /etc/Muttrc
    echo 'source ~/.mutt-alias' >> /etc/Muttrc
    echo 'set query_command= "abook --mutt-query \"%s\""' >> /etc/Muttrc
    echo 'macro index,pager A "<pipe-message>abook --add-email-quiet<return>" "add the sender address to abook"' >> /etc/Muttrc
    echo '' >> /etc/Muttrc
    echo '# Optional relay of SMTP via ISP' >> /etc/Muttrc
    echo '#set smtp_url="smtps://username:password@isp_mail_domain:465/"' >> /etc/Muttrc

    # For viewing long URLs
    echo 'REGEXP (((http|https|ftp|gopher)|mailto)[.:][^ >"\t]*|www\.[-a-z0-9.]+)[^ .,;\t>">\):]' > /home/$MY_USERNAME/.urlview
    echo 'COMMAND lynx -dump -width=78 -nolist %s' >> /home/$MY_USERNAME/.urlview

    cp -f /etc/Muttrc /home/$MY_USERNAME/.muttrc
    cp -f /etc/Muttrc /etc/skel/.muttrc
    cp -f /home/$MY_USERNAME/.urlview /etc/skel/.urlview
    touch /home/$MY_USERNAME/.mutt-alias
    cp /home/$MY_USERNAME/.mutt-alias /etc/skel/.mutt-alias
    chown $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/.muttrc
    chown $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/.mutt-alias

    # default user on generic images
    if [ -d /home/${GENERIC_IMAGE_USERNAME} ]; then
        cp -f /etc/Muttrc /home/${GENERIC_IMAGE_USERNAME}/.muttrc
        chown ${GENERIC_IMAGE_USERNAME}:${GENERIC_IMAGE_USERNAME} /home/${GENERIC_IMAGE_USERNAME}/.muttrc
        touch /home/${GENERIC_IMAGE_USERNAME}/.mutt-alias
        chown ${GENERIC_IMAGE_USERNAME}:${GENERIC_IMAGE_USERNAME} /home/${GENERIC_IMAGE_USERNAME}/.mutt-alias
    fi

    mark_completed $FUNCNAME
}

function email_archiving {
    if [ ! -d /etc/exim4 ]; then
        return
    fi

    # ensure that the mail archive script is up to date
    if [ -f /usr/local/bin/${PROJECT_NAME}-archive-mail ]; then
        if [ ! -f /etc/cron.daily/archivemail ]; then
            cp /usr/local/bin/${PROJECT_NAME}-archive-mail /etc/cron.daily/archivemail
            chmod +x /etc/cron.daily/archivemail
        else
            HASH1=$(sha256sum /usr/local/bin/${PROJECT_NAME}-archive-mail | awk -F ' ' '{print $1}')
            HASH2=$(sha256sum /etc/cron.daily/archivemail | awk -F ' ' '{print $1}')
            if [[ "$HASH1" != "$HASH2" ]]; then
                cp /usr/local/bin/${PROJECT_NAME}-archive-mail /etc/cron.daily/archivemail
                chmod +x /etc/cron.daily/archivemail
            fi
        fi
    else
        if [ -f /usr/bin/${PROJECT_NAME}-archive-mail ]; then
            if [ ! -f /etc/cron.daily/archivemail ]; then
                cp /usr/bin/${PROJECT_NAME}-archive-mail /etc/cron.daily/archivemail
                chmod +x /etc/cron.daily/archivemail
            else
                HASH1=$(sha256sum /usr/local/bin/${PROJECT_NAME}-archive-mail | awk -F ' ' '{print $1}')
                HASH2=$(sha256sum /etc/cron.daily/archivemail | awk -F ' ' '{print $1}')
                if [[ "$HASH1" != "$HASH2" ]]; then
                    cp /usr/local/bin/${PROJECT_NAME}-archive-mail /etc/cron.daily/archivemail
                    chmod +x /etc/cron.daily/archivemail
                fi
            fi
        else
            echo "/usr/bin/${PROJECT_NAME}-archive-mail was not found. ${PROJECT_NAME} might not have fully installed."
            exit 62379
        fi
    fi

    # update to the next commit
    function_check set_repo_commit
    set_repo_commit $INSTALL_DIR/cleanup-maildir "cleanup-maildir commit" "$CLEANUP_MAILDIR_COMMIT" $CLEANUP_MAILDIR_REPO

    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi

    if [ ! -d $INSTALL_DIR ]; then
        mkdir $INSTALL_DIR
    fi
    cd $INSTALL_DIR
    function_check git_clone
    git_clone $CLEANUP_MAILDIR_REPO $INSTALL_DIR/cleanup-maildir
    cd $INSTALL_DIR/cleanup-maildir
    git checkout $CLEANUP_MAILDIR_COMMIT -b $CLEANUP_MAILDIR_COMMIT
    set_completion_param "cleanup-maildir commit" "$CLEANUP_MAILDIR_COMMIT"

    if [ ! -f /usr/bin/cleanup-maildir ]; then
        cp $INSTALL_DIR/cleanup-maildir/cleanup-maildir /usr/bin
    else
        HASH1=$(sha256sum $INSTALL_DIR/cleanup-maildir/cleanup-maildir | awk -F ' ' '{print $1}')
        HASH2=$(sha256sum /usr/bin/cleanup-maildir | awk -F ' ' '{print $1}')
        if [[ "$HASH1" != "$HASH2" ]]; then
            cp $INSTALL_DIR/cleanup-maildir/cleanup-maildir /usr/bin
        fi
    fi

    mark_completed $FUNCNAME
}

# Ensure that the from field is correct when sending email from Mutt
function email_from_address {
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi

    if [ ! -f /home/$MY_USERNAME/.muttrc ]; then
        return
    fi
    if grep -q "set from=" /home/$MY_USERNAME/.muttrc; then
        sed -i "s|set from=.*|set from='$MY_NAME <$MY_EMAIL_ADDRESS>'|g" /home/$MY_USERNAME/.muttrc
    else
        echo "set from='$MY_NAME <$MY_EMAIL_ADDRESS>'" >> /home/$MY_USERNAME/.muttrc
    fi

    mark_completed $FUNCNAME
}

function create_public_mailing_list {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    if [ ! $PUBLIC_MAILING_LIST ]; then
        return
    fi
    # does the mailing list have a separate domain name?
    if [ ! $PUBLIC_MAILING_LIST_DOMAIN_NAME ]; then
        PUBLIC_MAILING_LIST_DOMAIN_NAME=$DEFAULT_DOMAIN_NAME
    fi

    PUBLIC_MAILING_LIST_USER="mlmmj"

    apt-get -yq install mlmmj
    adduser --system $PUBLIC_MAILING_LIST_USER
    addgroup $PUBLIC_MAILING_LIST_USER
    adduser $PUBLIC_MAILING_LIST_USER $PUBLIC_MAILING_LIST_USER

    echo ''
    echo $"Creating the $PUBLIC_MAILING_LIST mailing list"
    echo ''

    # create the list
    mlmmj-make-ml -a -L "$PUBLIC_MAILING_LIST" -c $PUBLIC_MAILING_LIST_USER

    echo 'SYSTEM_ALIASES_PIPE_TRANSPORT = address_pipe' > /etc/exim4/conf.d/main/000_localmacros
    echo "SYSTEM_ALIASES_USER = $PUBLIC_MAILING_LIST_USER" >> /etc/exim4/conf.d/main/000_localmacros
    echo "SYSTEM_ALIASES_GROUP = $PUBLIC_MAILING_LIST_USER" >> /etc/exim4/conf.d/main/000_localmacros

    # router
    echo 'mlmmj_router:' > /etc/exim4/conf.d/router/750_exim4-config_mlmmj
    echo '  debug_print = "R: mlmmj_router for $local_part@$domain"' >> /etc/exim4/conf.d/router/750_exim4-config_mlmmj
    echo '  driver = accept' >> /etc/exim4/conf.d/router/750_exim4-config_mlmmj
    echo '  domains = +mlmmj_domains' >> /etc/exim4/conf.d/router/750_exim4-config_mlmmj
    echo '  #require_files = MLMMJ_HOME/${lc::$local_part}' >> /etc/exim4/conf.d/router/750_exim4-config_mlmmj
    echo '  # Use this instead, if you dont want to give Exim rx rights to mlmmj spool.' >> /etc/exim4/conf.d/router/750_exim4-config_mlmmj
    echo '  # Exim will then spawn a new process running under the UID of "mlmmj".' >> /etc/exim4/conf.d/router/750_exim4-config_mlmmj
    echo '  require_files = mlmmj:MLMMJ_HOME/${lc::$local_part}' >> /etc/exim4/conf.d/router/750_exim4-config_mlmmj
    echo '  local_part_suffix = +*' >> /etc/exim4/conf.d/router/750_exim4-config_mlmmj
    echo '  local_part_suffix_optional' >> /etc/exim4/conf.d/router/750_exim4-config_mlmmj
    echo '  headers_remove = Delivered-To' >> /etc/exim4/conf.d/router/750_exim4-config_mlmmj
    echo '  headers_add = Delivered-To: $local_part$local_part_suffix@$domain' >> /etc/exim4/conf.d/router/750_exim4-config_mlmmj
    echo '  transport = mlmmj_transport' >> /etc/exim4/conf.d/router/750_exim4-config_mlmmj

    # transport
    echo 'mlmmj_transport:' > /etc/exim4/conf.d/transport/40_exim4-config_mlmmj
    echo '  debug_print = "T: mlmmj_transport for $local_part@$domain"' >> /etc/exim4/conf.d/transport/40_exim4-config_mlmmj
    echo '  driver = pipe' >> /etc/exim4/conf.d/transport/40_exim4-config_mlmmj
    echo '  return_path_add' >> /etc/exim4/conf.d/transport/40_exim4-config_mlmmj
    echo '  user = mlmmj' >> /etc/exim4/conf.d/transport/40_exim4-config_mlmmj
    echo '  group = mlmmj' >> /etc/exim4/conf.d/transport/40_exim4-config_mlmmj
    echo '  home_directory = MLMMJ_HOME' >> /etc/exim4/conf.d/transport/40_exim4-config_mlmmj
    echo '  current_directory = MLMMJ_HOME' >> /etc/exim4/conf.d/transport/40_exim4-config_mlmmj
    echo '  command = /usr/bin/mlmmj-receive -F -L MLMMJ_HOME/${lc:$local_part}' >> /etc/exim4/conf.d/transport/40_exim4-config_mlmmj

    if ! grep -q "MLMMJ_HOME=/var/spool/mlmmj" /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs; then
        sed -i '/MAIN CONFIGURATION SETTINGS/a\MLMMJ_HOME=/var/spool/mlmmj' /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs
    fi
    if ! grep -q "domainlist mlmmj_domains =" /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs; then
        sed -i "/MLMMJ_HOME/a\domainlist mlmmj_domains = $PUBLIC_MAILING_LIST_DOMAIN_NAME" /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs
    fi


    if ! grep -q "delay_warning_condition =" /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs; then
        sed -i '/domainlist mlmmj_domains =/a\delay_warning_condition = ${if match_domain{$domain}{+mlmmj_domains}{no}{yes}}' /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs
    fi
    if ! grep -q ": +mlmmj_domains" /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs; then
        sed -i 's/domainlist relay_to_domains = MAIN_RELAY_TO_DOMAINS/domainlist relay_to_domains = MAIN_RELAY_TO_DOMAINS : +mlmmj_domains/g' /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs
    fi

    if ! grep -q "! +mlmmj_domains" /etc/exim4/conf.d/router/200_exim4-config_primary; then
        sed -i 's/domains = ! +local_domains/domains = ! +mlmmj_domains : ! +local_domains/g' /etc/exim4/conf.d/router/200_exim4-config_primary
    fi
    update-exim4.conf.template -r
    update-exim4.conf
    systemctl restart exim4

    if ! grep -q $"$PUBLIC_MAILING_LIST mailing list" /home/$MY_USERNAME/README; then
        echo '' >> /home/$MY_USERNAME/README
        echo '' >> /home/$MY_USERNAME/README
        echo $"$PUBLIC_MAILING_LIST mailing list" >> /home/$MY_USERNAME/README
        echo '=================================' >> /home/$MY_USERNAME/README
        echo $"To subscribe to the $PUBLIC_MAILING_LIST mailing list send a" >> /home/$MY_USERNAME/README
        echo $"cleartext email to $PUBLIC_MAILING_LIST+subscribe@$DEFAULT_DOMAIN_NAME" >> /home/$MY_USERNAME/README
        chown $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/README
        chmod 600 /home/$MY_USERNAME/README
    fi

    ${PROJECT_NAME}-addlist -u $MY_USERNAME -l "$PUBLIC_MAILING_LIST" -s "$PUBLIC_MAILING_LIST"

    mark_completed $FUNCNAME
}

function create_private_mailing_list {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    if [ ! $PRIVATE_MAILING_LIST ]; then
        return
    fi
    if [[ $PRIVATE_MAILING_LIST == $MY_USERNAME ]]; then
        echo $'The name of the private mailing list should not be the same as your username'
        exit 10
    fi
    if [ ! $MY_GPG_PUBLIC_KEY ]; then
        echo $'To create a private mailing list you need to specify a file'
        echo $'containing your exported GPG key within MY_GPG_PUBLIC_KEY at'
        echo $'the top of the script'
        exit 11
    fi
    apt-get -yq install ruby ruby-dev ruby-gpgme libgpgme11-dev libmagic-dev
    gem install schleuder
    schleuder-fix-gem-dependencies
    schleuder-init-setup --gem
    # NOTE: this is version number sensitive and so might need changing
    ln -s /var/lib/gems/2.1.0/gems/schleuder-2.2.4 /var/lib/schleuder
    sed -i 's/#smtp_port: 25/smtp_port: 465/g' /etc/schleuder/schleuder.conf
    sed -i 's/#superadminaddr: root@localhost/superadminaddr: root@localhost' /etc/schleuder/schleuder.conf
    schleuder-newlist $PRIVATE_MAILING_LIST@$DEFAULT_DOMAIN_NAME -realname "$PRIVATE_MAILING_LIST" -adminaddress $MY_EMAIL_ADDRESS -initmember $MY_EMAIL_ADDRESS -initmemberkey $MY_GPG_PUBLIC_KEY -nointeractive
    ${PROJECT_NAME}-addemail -u $MY_USERNAME -e $PRIVATE_MAILING_LIST@$DEFAULT_DOMAIN_NAME -l $PRIVATE_MAILING_LIST

    echo 'schleuder:' > /etc/exim4/conf.d/router/550_exim4-config_schleuder
    echo '  debug_print = "R: schleuder for $local_part@$domain"' >> /etc/exim4/conf.d/router/550_exim4-config_schleuder
    echo '  driver = accept' >> /etc/exim4/conf.d/router/550_exim4-config_schleuder
    echo '  local_part_suffix_optional' >> /etc/exim4/conf.d/router/550_exim4-config_schleuder
    echo '  local_part_suffix = +* : -bounce : -sendkey' >> /etc/exim4/conf.d/router/550_exim4-config_schleuder
    echo '  domains = +local_domains' >> /etc/exim4/conf.d/router/550_exim4-config_schleuder
    echo '  user = schleuder' >> /etc/exim4/conf.d/router/550_exim4-config_schleuder
    echo '  group = schleuder' >> /etc/exim4/conf.d/router/550_exim4-config_schleuder
    echo '  require_files = schleuder:+/var/lib/schleuder/$domain/${local_part}' >> /etc/exim4/conf.d/router/550_exim4-config_schleuder
    echo '  transport = schleuder_transport' >> /etc/exim4/conf.d/router/550_exim4-config_schleuder

    echo 'schleuder_transport:' > /etc/exim4/conf.d/transport/30_exim4-config_schleuder
    echo '  debug_print = "T: schleuder_transport for $local_part@$domain"' >> /etc/exim4/conf.d/transport/30_exim4-config_schleuder
    echo '  driver = pipe' >> /etc/exim4/conf.d/transport/30_exim4-config_schleuder
    echo '  home_directory = "/var/lib/schleuder/$domain/$local_part"' >> /etc/exim4/conf.d/transport/30_exim4-config_schleuder
    echo '  command = "/usr/bin/schleuder $local_part@$domain"' >> /etc/exim4/conf.d/transport/30_exim4-config_schleuder
    chown -R schleuder:schleuder /var/lib/schleuder
    update-exim4.conf.template -r
    update-exim4.conf
    systemctl restart exim4
    chmod 600 /etc/shadow
    chmod 600 /etc/gshadow
    useradd -d /var/schleuderlists -s /bin/false schleuder
    adduser Debian-exim schleuder
    usermod -a -G mail schleuder
    chmod 0000 /etc/shadow
    chmod 0000 /etc/gshadow
    #exim -d -bt $PRIVATE_MAILING_LIST@$DEFAULT_DOMAIN_NAME
    mark_completed $FUNCNAME
}

function split_gpg_key_into_fragments {
    # split the gpg key into fragments if social key management is enabled
    if [[ $ENABLE_SOCIAL_KEY_MANAGEMENT == "yes" ]]; then

        if [ $IMAGE_PASSWORD_FILE ]; then
            if [ -f $IMAGE_PASSWORD_FILE ]; then
                ${PROJECT_NAME}-splitkey -u $MY_USERNAME -e $MY_EMAIL_ADDRESS --fullname "$MY_NAME" --passwordfile $IMAGE_PASSWORD_FILE
                return
            fi
        fi

        echo 'Splitting GPG key. You may need to enter your passphrase.'
        ${PROJECT_NAME}-splitkey -u $MY_USERNAME -e $MY_EMAIL_ADDRESS --fullname "$MY_NAME"
        if [ ! -d /home/$MY_USERNAME/.gnupg_fragments ]; then
            echo 'Yhe GPG key could not be split'
            exit 86548
        fi
    fi
}

function import_email {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    EMAIL_COMPLETE_MSG=$"
  *** ${PROJECT_NAME} mailbox installation is complete ***

      Now on your internet router forward ports
     25, 587, 465, 993 and 2222 to the ${PROJECT_NAME}
"
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        if [[ $SYSTEM_TYPE == "mail"* ]]; then
            function_check backup_to_friends_servers
            backup_to_friends_servers

            function_check install_tripwire
            install_tripwire

            function_check split_gpg_key_into_fragments
            split_gpg_key_into_fragments

            clear
            echo ''
            echo "$EMAIL_COMPLETE_MSG"
            if [ -d $USB_MOUNT ]; then
                umount $USB_MOUNT
                rm -rf $USB_MOUNT
                echo $'            You can now remove the USB drive'
            fi
            exit 0
        fi
        return
    fi
    mark_completed $FUNCNAME
    if [[ $SYSTEM_TYPE == "mail"* ]]; then
        function_check backup_to_friends_servers
        backup_to_friends_servers

        function_check install_tripwire
        install_tripwire

        function_check split_gpg_key_into_fragments
        split_gpg_key_into_fragments

        # unmount any attached usb drive
        clear
        echo ''
        echo "$EMAIL_COMPLETE_MSG"
        echo ''
        if [ -d $USB_MOUNT ]; then
            umount $USB_MOUNT
            rm -rf $USB_MOUNT
            echo $'            You can now remove the USB drive'
        fi
        exit 0
    fi
}

function remove_email {
    echo ''
}

function install_email_basic {
    apt-get -yq remove postfix
    apt-get -yq install exim4 sasl2-bin swaks libnet-ssleay-perl procmail

    if [ ! -d /etc/exim4 ]; then
        echo $"ERROR: Exim does not appear to have installed. $CHECK_MESSAGE"
        exit 48
    fi

    # configure for Maildir format
    sed -i 's/MAIL_DIR/#MAIL_DIR/g' /etc/login.defs
    sed -i 's|#MAIL_FILE.*|MAIL_FILE Maildir/|g' /etc/login.defs

    if ! grep -q "export MAIL" /etc/profile; then
        echo 'export MAIL=~/Maildir' >> /etc/profile
    fi

    sed -i 's|pam_mail.so standard|pam_mail.so dir=~/Maildir standard|g' /etc/pam.d/login
    sed -i 's|pam_mail.so standard noenv|pam_mail.so dir=~/Maildir standard|g' /etc/pam.d/sshd
    sed -i 's|pam_mail.so nopen|pam_mail.so dir=~/Maildir nopen|g' /etc/pam.d/su

    echo "dc_eximconfig_configtype='internet'" > /etc/exim4/update-exim4.conf.conf
    echo "dc_other_hostnames='${DEFAULT_DOMAIN_NAME};mail.${DEFAULT_DOMAIN_NAME}'" >> /etc/exim4/update-exim4.conf.conf
    echo "dc_local_interfaces=''" >> /etc/exim4/update-exim4.conf.conf
    echo "dc_readhost=''" >> /etc/exim4/update-exim4.conf.conf
    echo "dc_relay_domains=''" >> /etc/exim4/update-exim4.conf.conf
    echo "dc_minimaldns='false'" >> /etc/exim4/update-exim4.conf.conf
    IPv4_address=$(get_ipv4_address)
    IPv4_address_base=$(echo "$IPv4_address" | awk -F '.' '{print $1"."$2"."$3}')
    RELAY_NETS="${IPv4_address_base}.0/24"
    if [ $LOCAL_NETWORK_STATIC_IP_ADDRESS ]; then
        RELAY_NETS=$(echo $LOCAL_NETWORK_STATIC_IP_ADDRESS | awk -F '.' '{print $1 "." $2 "." $3 ".0/24"}')
    fi
    echo "dc_relay_nets='$RELAY_NETS'" >> /etc/exim4/update-exim4.conf.conf
    echo "dc_smarthost=''" >> /etc/exim4/update-exim4.conf.conf
    echo "CFILEMODE='644'" >> /etc/exim4/update-exim4.conf.conf
    echo "dc_use_split_config='false'" >> /etc/exim4/update-exim4.conf.conf
    echo "dc_hide_mailname=''" >> /etc/exim4/update-exim4.conf.conf
    echo "dc_mailname_in_oh='true'" >> /etc/exim4/update-exim4.conf.conf
    echo "dc_localdelivery='maildir_home'" >> /etc/exim4/update-exim4.conf.conf
    echo "dc_main_log_selector=-all" >> /etc/exim4/update-exim4.conf.conf
    update-exim4.conf
    sed -i "s/START=no/START=yes/g" /etc/default/saslauthd
    systemctl start saslauthd

    email_install_tls

    adduser $MY_USERNAME sasl
    addgroup Debian-exim sasl
    systemctl restart exim4

    email_create_template

    if [ -f /usr/sbin/exim ]; then
        chmod u+s /usr/sbin/exim
    fi
    if [ -f /usr/sbin/exim4 ]; then
        chmod u+s /usr/sbin/exim4
    fi

    function_check configure_firewall_for_email
    configure_firewall_for_email
    dpkg-reconfigure --frontend noninteractive exim4-config
    systemctl restart exim4
}

function email_change_relay {
    curr_ip_address="$1"
    email_relay_base=$(echo "$curr_ip_address" | awk -F '.' '{print $1"."$2"."$3}')
    RELAY_NETS="${email_relay_base}.0/24"
    sed -i "s|dc_relay_nets=.*|dc_relay_nets='$RELAY_NETS'|g" /etc/exim4/update-exim4.conf.conf
    dpkg-reconfigure --frontend noninteractive exim4-config
}

function create_procmail {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    if [ ! -f /home/$MY_USERNAME/.procmailrc ]; then
        echo 'MAILDIR=$HOME/Maildir' > /home/$MY_USERNAME/.procmailrc
        echo 'DEFAULT=$MAILDIR/' >> /home/$MY_USERNAME/.procmailrc
        echo 'LOGFILE=$HOME/log/procmail.log' >> /home/$MY_USERNAME/.procmailrc
        echo 'LOGABSTRACT=all' >> /home/$MY_USERNAME/.procmailrc
        echo '' >> /home/$MY_USERNAME/.procmailrc
        echo '# Test for an empty or missing subject line' >> /home/$MY_USERNAME/.procmailrc
        echo 'SUBJ_=$(formail -xSubject: \' >> /home/$MY_USERNAME/.procmailrc
        echo "        | expand | sed -e 's/^[ ]*//g' -e 's/[ ]*\$//g')" >> /home/$MY_USERNAME/.procmailrc
        echo ':0' >> /home/$MY_USERNAME/.procmailrc
        echo '  * SUBJ_ ?? ^^^^' >> /home/$MY_USERNAME/.procmailrc
        echo '/dev/null' >> /home/$MY_USERNAME/.procmailrc
        echo '' >> /home/$MY_USERNAME/.procmailrc
        echo $"# Tripwire reports which have no violations don't need to be logged" >> /home/$MY_USERNAME/.procmailrc
        echo ':0 BD:' >> /home/$MY_USERNAME/.procmailrc
        TRIPWIRE_VIOLATIONS_STR=$'Total violations found:  0'
        echo "  * .*$TRIPWIRE_VIOLATIONS_STR" >> /home/$MY_USERNAME/.procmailrc
        echo '/dev/null' >> /home/$MY_USERNAME/.procmailrc
        echo '' >> /home/$MY_USERNAME/.procmailrc
        chown $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/.procmailrc
    fi

    mkdir -p /home/$MY_USERNAME/Maildir/admin/new
    mkdir -p /home/$MY_USERNAME/Maildir/admin/cur
    chown -R $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/Maildir/admin

    if [ ! -f /etc/skel/.procmailrc ]; then
        cp /home/$MY_USERNAME/.procmailrc /etc/skel/.procmailrc
        chown root:root /etc/skel/.procmailrc
    fi

    if [ -f /usr/bin/procmail ]; then
        chmod 6755 /usr/bin/procmail
    fi

    mark_completed $FUNCNAME
}

function handle_admin_emails {
    # keep emails for root in a separate folder
    if [ -d /home/$MY_USERNAME/Maildir/admin ]; then
        return
    fi

    ${PROJECT_NAME}-addemail -u $MY_USERNAME -e "root@$DEFAULT_DOMAIN_NAME" -g admin --public no
}

function spam_filtering {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    apt-get -yq install exim4-daemon-heavy
    apt-get -yq install spamassassin
    if [ ! -f /etc/default/spamassassin ]; then
        echo 'Spamassassin was not installed'
        exit 72570
    fi
    sa-update -v
    sed -i 's/ENABLED=0/ENABLED=1/g' /etc/default/spamassassin
    sed -i 's/# spamd_address = 127.0.0.1 783/spamd_address = 127.0.0.1 783/g' /etc/exim4/exim4.conf.template
    # This configuration is based on https://wiki.debian.org/DebianSpamAssassin
    sed -i 's/local_parts = postmaster/local_parts = postmaster:abuse/g' /etc/exim4/conf.d/acl/30_exim4-config_check_rcpt
    sed -i '/domains = +local_domains : +relay_to_domains/a\    set acl_m0 = rfcnames' /etc/exim4/conf.d/acl/30_exim4-config_check_rcpt
    sed -i 's/accept/accept condition = ${if eq{$acl_m0}{rfcnames} {1}{0}}/g' /etc/exim4/conf.d/acl/40_exim4-config_check_data
    echo 'warn  message = X-Spam-Score: $spam_score ($spam_bar)' >> /etc/exim4/conf.d/acl/40_exim4-config_check_data
    echo '      spam = nobody:true' >> /etc/exim4/conf.d/acl/40_exim4-config_check_data
    echo 'warn  message = X-Spam-Flag: YES' >> /etc/exim4/conf.d/acl/40_exim4-config_check_data
    echo '      spam = nobody' >> /etc/exim4/conf.d/acl/40_exim4-config_check_data
    echo 'warn  message = X-Spam-Report: $spam_report' >> /etc/exim4/conf.d/acl/40_exim4-config_check_data
    echo '      spam = nobody' >> /etc/exim4/conf.d/acl/40_exim4-config_check_data
    echo '# reject spam at high scores (> 12)' >> /etc/exim4/conf.d/acl/40_exim4-config_check_data
    echo 'deny  message = This message scored $spam_score spam points.' >> /etc/exim4/conf.d/acl/40_exim4-config_check_data
    echo '      spam = nobody:true' >> /etc/exim4/conf.d/acl/40_exim4-config_check_data
    echo '      condition = ${if >{$spam_score_int}{120}{1}{0}}' >> /etc/exim4/conf.d/acl/40_exim4-config_check_data
    # procmail configuration
    echo '# get spamassassin to check emails' >> /home/$MY_USERNAME/.procmailrc
    echo ':0fw: .spamassassin.lock' >> /home/$MY_USERNAME/.procmailrc
    echo '  * < 256000' >> /home/$MY_USERNAME/.procmailrc
    echo '| spamc' >> /home/$MY_USERNAME/.procmailrc
    echo '# strong spam are discarded' >> /home/$MY_USERNAME/.procmailrc
    echo ':0' >> /home/$MY_USERNAME/.procmailrc
    echo '  * ^X-Spam-Level: \*\*\*\*\*\*' >> /home/$MY_USERNAME/.procmailrc
    echo '/dev/null' >> /home/$MY_USERNAME/.procmailrc
    echo '# weak spam are kept just in case - clear this out every now and then' >> /home/$MY_USERNAME/.procmailrc
    echo ':0' >> /home/$MY_USERNAME/.procmailrc
    echo '  * ^X-Spam-Level: \*\*\*\*\*' >> /home/$MY_USERNAME/.procmailrc
    echo 'maybe-spam/' >> /home/$MY_USERNAME/.procmailrc
    echo '# otherwise, marginal spam goes here for revision' >> /home/$MY_USERNAME/.procmailrc
    echo ':0' >> /home/$MY_USERNAME/.procmailrc
    echo '  * ^X-Spam-Level: \*\*' >> /home/$MY_USERNAME/.procmailrc
    echo 'spam/' >> /home/$MY_USERNAME/.procmailrc
    chown $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/.procmailrc
    echo '# get spamassassin to check emails' >> /etc/skel/.procmailrc
    echo ':0fw: .spamassassin.lock' >> /etc/skel/.procmailrc
    echo '  * < 256000' >> /etc/skel/.procmailrc
    echo '| spamc' >> /etc/skel/.procmailrc
    echo '# strong spam are discarded' >> /etc/skel/.procmailrc
    echo ':0' >> /etc/skel/.procmailrc
    echo '  * ^X-Spam-Level: \*\*\*\*\*\*' >> /etc/skel/.procmailrc
    echo '/dev/null' >> /etc/skel/.procmailrc
    echo '# weak spam are kept just in case - clear this out every now and then' >> /etc/skel/.procmailrc
    echo ':0' >> /etc/skel/.procmailrc
    echo '  * ^X-Spam-Level: \*\*\*\*\*' >> /etc/skel/.procmailrc
    echo 'maybe-spam/' >> /etc/skel/.procmailrc
    echo '# otherwise, marginal spam goes here for revision' >> /etc/skel/.procmailrc
    echo ':0' >> /etc/skel/.procmailrc
    echo '  * ^X-Spam-Level: \*\*' >> /etc/skel/.procmailrc
    echo 'spam/' >> /etc/skel/.procmailrc
    # filtering scripts
    echo '#!/bin/bash' > /usr/bin/filterspam
    echo 'for d in /home/*/ ; do' >> /usr/bin/filterspam
    echo '    USERNAME=$(echo "$d" | awk -F '"'"'/'"'"' '"'"'{print $3}'"'"')' >> /usr/bin/filterspam
    echo '    if [[ $USERNAME != "git" && $USERNAME != "go" && $USERNAME != "gogs" && $USERNAME != "sync" && $USERNAME != "tahoelafs" ]]; then' >> /usr/bin/filterspam
    echo '        MAILDIR=/home/$USERNAME/Maildir/.learn-spam' >> /usr/bin/filterspam
    echo '        if [ ! -d "$MAILDIR" ]; then' >> /usr/bin/filterspam
    echo '           exit' >> /usr/bin/filterspam
    echo '        fi' >> /usr/bin/filterspam
    echo '        for f in `ls $MAILDIR/cur`' >> /usr/bin/filterspam
    echo '        do' >> /usr/bin/filterspam
    echo '            spamc -L spam < "$MAILDIR/cur/$f" > /dev/null' >> /usr/bin/filterspam
    echo '            rm "$MAILDIR/cur/$f"' >> /usr/bin/filterspam
    echo '        done' >> /usr/bin/filterspam
    echo '        for f in `ls $MAILDIR/new`' >> /usr/bin/filterspam
    echo '        do' >> /usr/bin/filterspam
    echo '            spamc -L spam < "$MAILDIR/new/$f" > /dev/null' >> /usr/bin/filterspam
    echo '            rm "$MAILDIR/new/$f"' >> /usr/bin/filterspam
    echo '        done' >> /usr/bin/filterspam
    echo '    fi' >> /usr/bin/filterspam
    echo 'done' >> /usr/bin/filterspam
    echo 'exit 0' >> /usr/bin/filterspam

    echo '#!/bin/bash' > /usr/bin/filterham
    echo 'for d in /home/*/ ; do' >> /usr/bin/filterham
    echo '    USERNAME=$(echo "$d" | awk -F '"'"'/'"'"' '"'"'{print $3}'"'"')' >> /usr/bin/filterham
    echo '    if [[ $USERNAME != "git" && $USERNAME != "go" && $USERNAME != "gogs" && $USERNAME != "sync" && $USERNAME != "tahoelafs" ]]; then' >> /usr/bin/filterham
    echo '        MAILDIR=/home/$USERNAME/Maildir/.learn-ham' >> /usr/bin/filterham
    echo '        if [ ! -d "$MAILDIR" ]; then' >> /usr/bin/filterham
    echo '            exit' >> /usr/bin/filterham
    echo '        fi' >> /usr/bin/filterham
    echo '        for f in `ls $MAILDIR/cur`' >> /usr/bin/filterham
    echo '        do' >> /usr/bin/filterham
    echo '            spamc -L ham < "$MAILDIR/cur/$f" > /dev/null' >> /usr/bin/filterham
    echo '            rm "$MAILDIR/cur/$f"' >> /usr/bin/filterham
    echo '        done' >> /usr/bin/filterham
    echo '        for f in `ls $MAILDIR/new`' >> /usr/bin/filterham
    echo '        do' >> /usr/bin/filterham
    echo '            spamc -L ham < "$MAILDIR/new/$f" > /dev/null' >> /usr/bin/filterham
    echo '            rm "$MAILDIR/new/$f"' >> /usr/bin/filterham
    echo '        done' >> /usr/bin/filterham
    echo '    fi' >> /usr/bin/filterham
    echo 'done' >> /usr/bin/filterham
    echo 'exit 0' >> /usr/bin/filterham

    function_check cron_add_mins
    cron_add_mins 3 '/usr/bin/timeout 120 /usr/bin/filterspam'
    cron_add_mins 3 '/usr/bin/timeout 120 /usr/bin/filterham'
    chmod 655 /usr/bin/filterspam /usr/bin/filterham
    sed -i 's/# use_bayes 1/use_bayes 1/g' /etc/mail/spamassassin/local.cf
    sed -i 's/# bayes_auto_learn 1/bayes_auto_learn 1/g' /etc/mail/spamassassin/local.cf

    # user preferences
    if [ ! -d /home/$MY_USERNAME/.spamassassin ]; then
        mkdir /home/$MY_USERNAME/.spamassassin
        echo $'# How many points before a mail is considered spam.' > /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '# required_score        5' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# Whitelist and blacklist addresses are now file-glob-style patterns, so' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# "friend@somewhere.com", "*@isp.com", or "*.domain.net" will all work.' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '# whitelist_from    someone@somewhere.com' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# Add your own customised scores for some tests below.  The default scores are' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# read from the installed spamassassin rules files, but you can override them' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# here.  To see the list of tests and their default scores, go to' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '# http://spamassassin.apache.org/tests.html .' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '#' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '# score SYMBOLIC_TEST_NAME n.nn' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# Speakers of Asian languages, like Chinese, Japanese and Korean, will almost' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# definitely want to uncomment the following lines.  They will switch off some' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# rules that detect 8-bit characters, which commonly trigger on mails using CJK' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# character sets, or that assume a western-style charset is in use. ' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '# ' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '# score HTML_COMMENT_8BITS  0' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '# score UPPERCASE_25_50     0' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '# score UPPERCASE_50_75     0' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '# score UPPERCASE_75_100    0' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '# score OBSCURED_EMAIL      0' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# Speakers of any language that uses non-English, accented characters may wish' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# to uncomment the following lines.   They turn off rules that fire on' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# misformatted messages generated by common mail apps in contravention of the' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo $'# email RFCs.' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '' >> /home/$MY_USERNAME/.spamassassin/user_prefs
        echo '# score SUBJ_ILLEGAL_CHARS      0' >> /home/$MY_USERNAME/.spamassassin/user_prefs
    fi
    # this must be accessible by root
    chown -R $MY_USERNAME:root /home/$MY_USERNAME/.spamassassin

    # script to keep spamassassin running
    # There is a systemd script from the debian package, but it doesn't restart on failure
    # and also doesn't ensure start after networking is up. If that is eventually fixed
    # then this script and the cron job which runs it can be removed.
    script_name=/usr/bin/run-spamassassin
    echo '#!/bin/bash' > $script_name
    echo 'current_state=$(systemctl status spamassassin)' >> $script_name
    echo 'if [[ "$current_state" != *"(running)"* ]]; then' >> $script_name
    echo '    systemctl restart spamassassin' >> $script_name
    echo 'fi' >> $script_name
    echo 'exit 0' >> $script_name
    chmod +x $script_name

    systemctl start spamassassin
    systemctl restart exim4
    systemctl restart cron
    function_check cron_add_mins
    cron_add_mins 10 "$script_name 2> /dev/null"

    mark_completed $FUNCNAME
}

function configure_imap {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi

    apt-get -yq install dovecot-imapd

    if [ ! -d /etc/dovecot ]; then
        echo $"ERROR: Dovecot does not appear to have installed. $CHECK_MESSAGE"
        exit 48
    fi

    if [[ "$(cert_exists dovecot)" == "0" ]]; then
        ${PROJECT_NAME}-addcert -h dovecot --dhkey $DH_KEYLENGTH
        check_certificates dovecot
    fi

    chmod 600 /etc/shadow
    chmod 600 /etc/gshadow
    groupadd default
    usermod -g default dovecot
    chmod 0000 /etc/shadow
    chmod 0000 /etc/gshadow

    chown root:default /etc/ssl/certs/dovecot.*
    chown root:default /etc/ssl/private/dovecot.*
    chown root:default /etc/ssl/certs/${DEFAULT_DOMAIN_NAME}.*
    chown root:default /etc/ssl/private/${DEFAULT_DOMAIN_NAME}.*

    if [ ! -f /etc/dovecot/conf.d/10-ssl.conf ]; then
        echo $'Unable to find /etc/dovecot/conf.d/10-ssl.conf'
        exit 83629
    fi
    sed -i 's|#ssl =.*|ssl = no|g' /etc/dovecot/conf.d/10-ssl.conf
    sed -i 's|ssl =.*|ssl = no|g' /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|#ssl_cert =.*|ssl_cert = </etc/ssl/certs/dovecot.crt|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|ssl_cert =.*|ssl_cert = </etc/ssl/certs/dovecot.crt|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|#ssl_key =.*|ssl_key = </etc/ssl/private/dovecot.key|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|ssl_key =.*|ssl_key = </etc/ssl/private/dovecot.key|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|#ssl_dh_parameters_length.*|ssl_dh_parameters_length = ${DH_KEYLENGTH}|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i 's/#ssl_prefer_server_ciphers.*/ssl_prefer_server_ciphers = yes/g' /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|#ssl_protocols =.*|ssl_protocols = '$SSL_PROTOCOLS'|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|ssl_protocols =.*|ssl_protocols = '$SSL_PROTOCOLS'|g" /etc/dovecot/conf.d/10-ssl.conf
    echo "ssl_cipher_list = '$SSL_CIPHERS'" >> /etc/dovecot/conf.d/10-ssl.conf

    if [ ! -f /etc/dovecot/conf.d/10-master.conf ]; then
        echo $'Unable to find /etc/dovecot/conf.d/10-master.conf'
        exit 49259
    fi
    sed -i 's/#process_limit =.*/process_limit = 100/g' /etc/dovecot/conf.d/10-master.conf

    if [ ! -f /etc/dovecot/conf.d/10-logging.conf ]; then
        echo $'Unable to find /etc/dovecot/conf.d/10-logging.conf'
        exit 48936
    fi
    sed -i 's/#auth_verbose.*/auth_verbose = yes/g' /etc/dovecot/conf.d/10-logging.conf

    if [ ! -f /etc/dovecot/dovecot.conf ]; then
        echo $'Unable to find /etc/dovecot/dovecot.conf'
        exit 43890
    fi
    sed -i 's/#listen =.*/listen = */g' /etc/dovecot/dovecot.conf

    if [ ! -f /etc/dovecot/conf.d/10-auth.conf ]; then
        echo $'Unable to find /etc/dovecot/conf.d/10-auth.conf'
        exit 843256
    fi
    sed -i 's/#disable_plaintext_auth =.*/disable_plaintext_auth = no/g' /etc/dovecot/conf.d/10-auth.conf
    sed -i 's/auth_mechanisms =.*/auth_mechanisms = plain login/g' /etc/dovecot/conf.d/10-auth.conf

    if [ ! -f /etc/dovecot/conf.d/10-mail.conf ]; then
        echo $'Unable to find /etc/dovecot/conf.d/10-mail.conf'
        exit 42036
    fi
    sed -i 's|mail_location =.*|mail_location = maildir:~/Maildir:LAYOUT=fs|g' /etc/dovecot/conf.d/10-mail.conf

    # This long notify interval makes the system more suited for use with
    # battery powered mobile devices
    sed -i 's|#imap_idle_notify_interval =.*|imap_idle_notify_interval = 29|g' /etc/dovecot/conf.d/20-imap.conf

    if [ -f /var/lib/dovecot/ssl-parameters.dat ]; then
        rm /var/lib/dovecot/ssl-parameters.dat
    fi

    if [ -f /etc/systemd/system/sockets.target.wants/dovecot.socket ]; then
        rm /etc/systemd/system/sockets.target.wants/dovecot.socket
    fi

    # Separate logging, otherwise syslog is used
    if ! grep -q "# logging" /etc/dovecot/dovecot.conf; then
        echo '' >> /etc/dovecot/dovecot.conf
        echo '# logging' >> /etc/dovecot/dovecot.conf
        echo 'log_path = /var/log/dovecot.log' >> /etc/dovecot/dovecot.conf
        echo 'info_log_path = /var/log/dovecot-info.log' >> /etc/dovecot/dovecot.conf
        echo 'debug_log_path = /var/log/dovecot-debug.log' >> /etc/dovecot/dovecot.conf
    fi

    systemctl restart dovecot
    mark_completed $FUNCNAME
}

function configure_imap_client_certs {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    # http://strange.systems/certificate-based-auth-with-dovecot-sendmail/
    sed -i 's|#default_process_limit =.*|default_process_limit = 100|g' /etc/dovecot/conf.d/10-master.conf
    sed -i 's/disable_plaintext_auth =.*/disable_plaintext_auth = yes/g' /etc/dovecot/conf.d/10-auth.conf
    sed -i 's|#auth_ssl_require_client_cert =.*|auth_ssl_require_client_cert = yes|g' /etc/dovecot/conf.d/10-auth.conf
    sed -i 's|#auth_ssl_username_from_cert =.*|auth_ssl_username_from_cert = yes|g' /etc/dovecot/conf.d/10-auth.conf
    sed -i "s|#ssl_ca =.*|ssl_ca = /etc/ssl/certs/ca-$DEFAULT_DOMAIN_NAME.crt|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i 's|#ssl_cert_username_field =.*|ssl_cert_username_field = commonName|g' /etc/dovecot/conf.d/10-ssl.conf
    sed -i 's|#ssl_verify_client_cert =.*|ssl_verify_client_cert = yes|g' /etc/dovecot/conf.d/10-ssl.conf
    if ! grep -q "passdb {" /etc/dovecot/conf.d/10-auth.conf; then
        echo '' >> /etc/dovecot/conf.d/10-auth.conf
        echo 'passdb {' >> /etc/dovecot/conf.d/10-auth.conf
        echo '  driver = passwd-file' >> /etc/dovecot/conf.d/10-auth.conf
        echo '  args = /etc/dovecot/passwd-file' >> /etc/dovecot/conf.d/10-auth.conf
        echo '  deny = no' >> /etc/dovecot/conf.d/10-auth.conf
        echo '  master = no' >> /etc/dovecot/conf.d/10-auth.conf
        echo '  pass = no' >> /etc/dovecot/conf.d/10-auth.conf
        echo '}' >> /etc/dovecot/conf.d/10-auth.conf
    fi
    if [[ $ONION_ONLY == "no" ]]; then
        # make a CA cert
        if [ ! -f /etc/ssl/private/ca-$DEFAULT_DOMAIN_NAME.key ]; then
            if [[ $LETSENCRYPT_ENABLED != "yes" ]]; then
                ${PROJECT_NAME}-addcert -h $DEFAULT_DOMAIN_NAME --ca "" --dhkey $DH_KEYLENGTH
            else
                ${PROJECT_NAME}-addcert -e $DEFAULT_DOMAIN_NAME -s $LETSENCRYPT_SERVER --ca "" --dhkey $DH_KEYLENGTH --email $MY_EMAIL_ADDRESS
            fi
        fi
    fi
    # CA configuration
    echo '[ ca ]' > /etc/ssl/dovecot-ca.cnf
    echo "default_ca = dovecot-ca" >> /etc/ssl/dovecot-ca.cnf
    echo '' >> /etc/ssl/dovecot-ca.cnf
    echo '[ crl_ext ]' >> /etc/ssl/dovecot-ca.cnf
    echo 'authorityKeyIdentifier=keyid:always' >> /etc/ssl/dovecot-ca.cnf
    echo '' >> /etc/ssl/dovecot-ca.cnf
    echo '[ dovecot-ca ]' >> /etc/ssl/dovecot-ca.cnf
    echo 'new_certs_dir = .' >> /etc/ssl/dovecot-ca.cnf
    echo 'unique_subject = no' >> /etc/ssl/dovecot-ca.cnf
    echo "certificate = /etc/ssl/certs/ca-$DEFAULT_DOMAIN_NAME.crt" >> /etc/ssl/dovecot-ca.cnf
    echo 'database = ssldb' >> /etc/ssl/dovecot-ca.cnf
    echo "private_key = /etc/ssl/private/ca-$DEFAULT_DOMAIN_NAME.key" >> /etc/ssl/dovecot-ca.cnf
    echo 'serial = sslserial' >> /etc/ssl/dovecot-ca.cnf
    echo 'default_days = 3650' >> /etc/ssl/dovecot-ca.cnf
    echo 'default_md = sha256' >> /etc/ssl/dovecot-ca.cnf
    echo 'default_bits = 2048' >> /etc/ssl/dovecot-ca.cnf
    echo 'policy = dovecot-ca_policy' >> /etc/ssl/dovecot-ca.cnf
    echo 'x509_extensions = dovecot-ca_extensions' >> /etc/ssl/dovecot-ca.cnf
    echo '' >> /etc/ssl/dovecot-ca.cnf
    echo '[ dovecot-ca_policy ]' >> /etc/ssl/dovecot-ca.cnf
    echo 'commonName = supplied' >> /etc/ssl/dovecot-ca.cnf
    echo 'stateOrProvinceName = supplied' >> /etc/ssl/dovecot-ca.cnf
    echo 'countryName = supplied' >> /etc/ssl/dovecot-ca.cnf
    echo 'emailAddress = optional' >> /etc/ssl/dovecot-ca.cnf
    echo 'organizationName = supplied' >> /etc/ssl/dovecot-ca.cnf
    echo 'organizationalUnitName = optional' >> /etc/ssl/dovecot-ca.cnf
    echo '' >> /etc/ssl/dovecot-ca.cnf
    echo '[ dovecot-ca_extensions ]' >> /etc/ssl/dovecot-ca.cnf
    echo 'basicConstraints = CA:false' >> /etc/ssl/dovecot-ca.cnf
    echo 'subjectKeyIdentifier = hash' >> /etc/ssl/dovecot-ca.cnf
    echo 'authorityKeyIdentifier = keyid:always' >> /etc/ssl/dovecot-ca.cnf
    echo 'keyUsage = digitalSignature,keyEncipherment' >> /etc/ssl/dovecot-ca.cnf
    echo 'extendedKeyUsage = clientAuth' >> /etc/ssl/dovecot-ca.cnf
    if [ -f /etc/ssl/ssldb ]; then
        rm /etc/ssl/ssldb
    fi
    if [ -f /etc/ssl/sslserial ]; then
        rm /etc/ssl/sslserial
    fi
    touch /etc/ssl/ssldb
    echo 0001 > /etc/ssl/sslserial
    #${PROJECT_NAME}-clientcert -u $MY_USERNAME
    systemctl restart dovecot
    mark_completed $FUNCNAME
}

function create_gpg_subkey {
    # Note: currently not used
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    apt-get -yq install gnupg

    GPG_KEY_USAGE=$1
    if [[ $GPG_KEY_USAGE != "sign" && $GPG_KEY_USAGE != "auth" && $GPG_KEY_USAGE != "encrypt" ]]; then
        echo $"Unknown subkey usage: $GPG_KEY_USAGE"
        echo $'Available types: sign|auth|encrypt'
        exit 14783
    fi

    KEYGRIP=$(gpg --fingerprint --fingerprint $MY_EMAIL_ADDRESS | grep fingerprint | tail -1 | cut -d= -f2 | sed -e 's/ //g')

    # Generate a GPG subkey
    echo 'Key-Type: eddsa' > /home/$MY_USERNAME/gpg-genkey.conf
    echo 'Key-Curve: Ed25519' >> /home/$MY_USERNAME/gpg-genkey.conf
    echo "Key-Grip: $KEYGRIP" >> /home/$MY_USERNAME/gpg-genkey.conf
    echo 'Subkey-Type: eddsa' >> /home/$MY_USERNAME/gpg-genkey.conf
    echo "subkey-Usage: $GPG_KEY_USAGE" > /home/$MY_USERNAME/gpg-genkey.conf
    echo "Name-Real:  $MY_NAME" >> /home/$MY_USERNAME/gpg-genkey.conf
    echo "Name-Email: $MY_EMAIL_ADDRESS" >> /home/$MY_USERNAME/gpg-genkey.conf
    echo "Name-Comment: $GPG_KEY_USAGE" >> /home/$MY_USERNAME/gpg-genkey.conf
    echo 'Expire-Date: 0' >> /home/$MY_USERNAME/gpg-genkey.conf
    echo "Passphrase: $PROJECT_NAME" >> /home/$MY_USERNAME/gpg-genkey.conf
    chown $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/gpg-genkey.conf
    su -m root -c "gpg --homedir /home/$MY_USERNAME/.gnupg --batch --full-gen-key /home/$MY_USERNAME/gpg-genkey.conf" - $MY_USERNAME
    chown -R $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/.gnupg

    shred -zu /home/$MY_USERNAME/gpg-genkey.conf

    MY_GPG_SUBKEY_ID=$(gpg_pubkey_from_email "$MY_USERNAME" "$MY_EMAIL_ADDRESS")

    mark_completed $FUNCNAME
}

function gpg_key_exists {
    key_owner_username=$1
    key_search_text=$2
    if [[ $key_owner_username != "root" ]]; then
        KEY_EXISTS=$(su -c "gpg --list-keys \"${key_search_text}\"" - $key_owner_username)
    else
        KEY_EXISTS=$(gpg --list-keys "${key_search_text}")
    fi
    if [ ! "$KEY_EXISTS" ]; then
        echo "no"
        return
    fi
    if [ "$KEY_EXISTS" == *"error"* ]; then
        echo "no"
        return
    fi
    echo "yes"
}

function configure_gpg {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    apt-get -yq install gnupg

    check_email_address_exists

    gpg_dir=/home/$MY_USERNAME/.gnupg

    # if gpg keys directory was previously imported from usb
    if [ -d $gpg_dir ]; then
        echo $'GPG directory exists'
    else
        echo $"GPG directory $gpg_dir was not found"
    fi
    if [ -d $gpg_dir ]; then
        echo $'GPG keys were imported'
        sed -i "s|keyserver hkp://keys.gnupg.net|keyserver $GPG_KEYSERVER|g" $gpg_dir/gpg.conf
        MY_GPG_PUBLIC_KEY_ID=$(gpg_pubkey_from_email "$MY_USERNAME" "$MY_EMAIL_ADDRESS")
        if [ ${#MY_GPG_PUBLIC_KEY_ID} -lt 4 ]; then
            echo $'GPG public key ID could not be obtained'
        fi
        chown -R $MY_USERNAME:$MY_USERNAME $gpg_dir
        chmod 700 $gpg_dir
        chmod 600 $gpg_dir/*
        mark_completed $FUNCNAME
        return
    fi

    if [ ! -d $gpg_dir ]; then
        mkdir $gpg_dir
        echo "keyserver $GPG_KEYSERVER" >> $gpg_dir/gpg.conf
        echo 'keyserver-options auto-key-retrieve' >> $gpg_dir/gpg.conf
    fi

    sed -i "s|keyserver hkp://keys.gnupg.net|keyserver $GPG_KEYSERVER|g" $gpg_dir/gpg.conf

    gpg_agent_setup root
    gpg_agent_setup $MY_USERNAME

    if ! grep -q "# default preferences" $gpg_dir/gpg.conf; then
        echo '' >> $gpg_dir/gpg.conf
        echo '# default preferences' >> $gpg_dir/gpg.conf
        echo 'personal-digest-preferences SHA256' >> $gpg_dir/gpg.conf
        echo 'cert-digest-algo SHA256' >> $gpg_dir/gpg.conf
        echo 'default-preference-list SHA512 SHA384 SHA256 SHA224 AES256 AES192 AES CAST5 ZLIB BZIP2 ZIP Uncompressed' >> $gpg_dir/gpg.conf
    fi

    chown -R $MY_USERNAME:$MY_USERNAME $gpg_dir
    chmod 700 $gpg_dir
    chmod 600 $gpg_dir/*

    if [[ $MY_GPG_PUBLIC_KEY && $MY_GPG_PRIVATE_KEY ]]; then
        echo $'Importing GPG keys from file'
        echo $"Public key:  $MY_GPG_PUBLIC_KEY"
        echo $"Private key: $MY_GPG_PRIVATE_KEY"

        # use your existing GPG keys which were exported
        if [ ! -f $MY_GPG_PUBLIC_KEY ]; then
            echo $"GPG public key file $MY_GPG_PUBLIC_KEY was not found"
            exit 2483
        fi

        if [ ! -f $MY_GPG_PRIVATE_KEY ]; then
            echo $"GPG private key file $MY_GPG_PRIVATE_KEY was not found"
            exit 5383
        fi

        gpg_import_public_key $MY_USERNAME $MY_GPG_PUBLIC_KEY
        gpg_import_private_key $MY_USERNAME $MY_GPG_PRIVATE_KEY

        KEY_EXISTS=$(gpg_key_exists "$MY_USERNAME" "$MY_EMAIL_ADDRESS")
        if [[ $KEY_EXISTS == "no" ]]; then
            echo $"The GPG key for $MY_EMAIL_ADDRESS could not be imported"
            exit 13821
        fi

        # for security ensure that the private key file doesn't linger around
        shred -zu $MY_GPG_PRIVATE_KEY
        MY_GPG_PUBLIC_KEY_ID=$(gpg_pubkey_from_email "$MY_USERNAME" "$MY_EMAIL_ADDRESS")
        if [ ${#MY_GPG_PUBLIC_KEY_ID} -lt 4 ]; then
            echo $'GPG public key ID could not be obtained'
        fi
    else
        # Generate a GPG key
        if [ -f $IMAGE_PASSWORD_FILE ]; then
            gpg_create_key $MY_USERNAME $(printf `cat $IMAGE_PASSWORD_FILE`)
        else
            gpg_create_key $MY_USERNAME $PROJECT_NAME
        fi
        MY_GPG_PUBLIC_KEY_ID=$(gpg_pubkey_from_email "$MY_USERNAME" "$MY_EMAIL_ADDRESS")
        MY_GPG_PUBLIC_KEY=/tmp/public_key.gpg
        gpg_export_public_key $MY_USERNAME $MY_GPG_PUBLIC_KEY_ID $MY_GPG_PUBLIC_KEY
    fi

    if [ ! -d /root/.gnupg ]; then
        cp -r /home/$MY_USERNAME/.gnupg /root/
        chmod 700 /root/.gnupg
        chmod 600 /root/.gnupg/*
    fi

    mark_completed $FUNCNAME
}

function refresh_gpg_keys {
    REFRESH_GPG_KEYS_SCRIPT=/tmp/update-gpg-keys
    echo '#!/bin/bash' > $REFRESH_GPG_KEYS_SCRIPT
    echo "if [ -f /usr/local/bin/${PROJECT_NAME}-sec ]; then" >> $REFRESH_GPG_KEYS_SCRIPT
    echo "    /usr/bin/timeout 600 /usr/local/bin/${PROJECT_NAME}-sec --refresh yes" >> $REFRESH_GPG_KEYS_SCRIPT
    echo 'else' >> $REFRESH_GPG_KEYS_SCRIPT
    echo "    /usr/bin/timeout 600 /usr/bin/${PROJECT_NAME}-sec --refresh yes" >> $REFRESH_GPG_KEYS_SCRIPT
    echo 'fi' >> $REFRESH_GPG_KEYS_SCRIPT
    echo 'exit 0' >> $REFRESH_GPG_KEYS_SCRIPT
    chmod +x $REFRESH_GPG_KEYS_SCRIPT

    if [ ! -f /usr/bin/update-gpg-keys ]; then
        cp $REFRESH_GPG_KEYS_SCRIPT /usr/bin/update-gpg-keys
    else
        HASH1=$(sha256sum $REFRESH_GPG_KEYS_SCRIPT | awk -F ' ' '{print $1}')
        HASH2=$(sha256sum /usr/bin/update-gpg-keys | awk -F ' ' '{print $1}')
        if [[ "$HASH1" != "$HASH2" ]]; then
            cp $REFRESH_GPG_KEYS_SCRIPT /usr/bin/update-gpg-keys
        fi
        rm $REFRESH_GPG_KEYS_SCRIPT
    fi

    REFRESH_GPG_KEYS_SCRIPT=/usr/bin/update-gpg-keys
    if grep -q "${PROJECT_NAME}-sec" /etc/crontab; then
        sed -i "/${PROJECT_NAME}-sec /d" /etc/crontab
    fi
    if ! grep -q "$REFRESH_GPG_KEYS_SCRIPT" /etc/crontab; then
        GPG_REFRESH_TIME=$(( RANDOM % 60 ))
        echo "$GPG_REFRESH_TIME            */$REFRESH_GPG_KEYS_HOURS *   *   *   root cronic $REFRESH_GPG_KEYS_SCRIPT" >> /etc/crontab
        systemctl restart cron
    else
        if ! grep "root cronic $REFRESH_GPG_KEYS_SCRIPT" /etc/crontab; then
            sed -i "s|root $REFRESH_GPG_KEYS_SCRIPT.*|root cronic $REFRESH_GPG_KEYS_SCRIPT|g" /etc/crontab
        fi
    fi
}

function install_email {
    if [[ $SYSTEM_TYPE == "mesh"* ]]; then
        return
    fi
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi

    check_email_address_exists
    install_email_basic
    configure_email_onion

    mark_completed $FUNCNAME
}

# NOTE: deliberately no exit 0