# -*-shell-script-*-
# This should be sourced by bash (though we welcome changes to make it POSIX sh compliant)

# Monkeysphere authentication setup subcommand
#
# The monkeysphere scripts are written by:
# Jameson Rollins <jrollins@finestructure.net>
# Jamie McClelland <jm@mayfirst.org>
# Daniel Kahn Gillmor <dkg@fifthhorseman.net>
#
# They are Copyright 2009, and are all released under the GPL,
# version 3 or later.

setup() {
    # make all needed directories
    log debug "checking authentication directory structure..."
    mkdir -p "${MADATADIR}"
    chmod 0750 "${MADATADIR}"
    chgrp "$MONKEYSPHERE_USER" "${MADATADIR}"
    mkdir -p "${MATMPDIR}"
    chmod 0750 "${MATMPDIR}"
    chgrp "$MONKEYSPHERE_USER" "${MATMPDIR}"
    mkdir -p "${GNUPGHOME_CORE}"
    chmod 0700 "${GNUPGHOME_CORE}"
    mkdir -p "${GNUPGHOME_SPHERE}"
    chmod 0700 "${GNUPGHOME_SPHERE}"
    mkdir -p "${SYSDATADIR}"/authorized_keys

    # deliberately replace the config files via truncation
    # FIXME: should we be dumping to tmp files and then moving atomically?
    log debug "writing core gpg.conf..."
    cat >"${GNUPGHOME_CORE}"/gpg.conf <<EOF
# Monkeysphere trust core GnuPG configuration
# This file is maintained by the Monkeysphere software.
# Edits will be overwritten.
no-greeting
EOF

    log debug "writing sphere gpg.conf..."
    cat >"${GNUPGHOME_SPHERE}"/gpg.conf <<EOF
# Monkeysphere trust sphere GnuPG configuration
# This file is maintained by the Monkeysphere software.
# Edits will be overwritten.
no-greeting
list-options show-uid-validity
EOF

    # make sure the monkeysphere user owns everything in the sphere
    # gnupghome
    log debug "fixing sphere gnupg home ownership..."
    chown "$MONKEYSPHERE_USER:$MONKEYSPHERE_USER" "${GNUPGHOME_SPHERE}" "${GNUPGHOME_SPHERE}"/gpg.conf

    # get fingerprint of core key.  this should be empty on unconfigured systems.
    local CORE_FPR=$(core_fingerprint)
    log debug "core fingerprint: $CORE_FPR"

    if [ -z "$CORE_FPR" ] ; then
	log info "setting up Monkeysphere authentication trust core..."

	local CORE_UID=$(printf "Monkeysphere authentication trust core UID (random string: %s)" $(head -c21 </dev/urandom | perl -MMIME::Base64 -ne 'print encode_base64($_)'))
    
	log debug "generating monkeysphere authentication trust core key ($CORE_KEYLENGTH bits)..."
	PEM2OPENPGP_USAGE_FLAGS=certify \
	    PEM2OPENPGP_NEWKEY=$CORE_KEYLENGTH pem2openpgp "$CORE_UID" \
	    | gpg_core --import \
	    || failure "Could not import new key for Monkeysphere authentication trust core"

	# get fingerprint of core key.  should definitely not be empty at this point
	CORE_FPR=$(core_fingerprint)
	log debug "core fingerprint: $CORE_FPR"
	if [ -z "$CORE_FPR" ] ; then
	    failure "Failed to create Monkeysphere authentication trust core!"
	fi
	
    else 
	log verbose "Monkeysphere authentication trust core already exists."
    fi

    # export the core key to the sphere keyring
    log debug "exporting core pub key to sphere keyring..."
    gpg_core --export | gpg_sphere "--import"

    # ensure that the authentication sphere checker has absolute ownertrust on the expected key.
    log debug "setting ultimate owner trust on core key in gpg_sphere..."
    printf "%s:6:\n" "$CORE_FPR" | gpg_sphere "--import-ownertrust" 2>&1 | log verbose
    gpg_sphere "--export-ownertrust" 2>&1 | log debug

    # check the owner trust
    log debug "checking gpg_sphere owner trust set properly..."
    local ORIG_TRUST
    if ORIG_TRUST=$(gpg_sphere "--export-ownertrust" | grep '^[^#]') ; then
	if [ "${CORE_FPR}:6:" != "$ORIG_TRUST" ] ; then
	    failure "Monkeysphere authentication trust sphere should explicitly trust the core.  It does not have proper ownertrust settings."
	fi
    else
	failure "Could not get monkeysphere-authentication trust guidelines."
	# FIXME: what does this mean?  should we suggest how to fix?
    fi

    # ensure that we're using the extended trust model (1), and that
    # our preferences are reasonable (i.e. 3 marginal OR 1 fully
    # trusted certifications are sufficient to grant full validity.
    log debug "checking trust model for authentication ..."
    local TRUST_MODEL=$(gpg_sphere "--with-colons --fixed-list-mode --list-keys" 2>/dev/null \
	| head -n1 | grep "^tru:" | cut -d: -f3,6,7)
    log debug "sphere trust model: $TRUST_MODEL"
    if [ "$TRUST_MODEL" != '1:3:1' ] ; then
	failure "monkeysphere-authentication does not have the expected trust model settings."
	# FIXME: what does this mean?  should we suggest how to fix?
    fi
}