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

# Monkeysphere authentication add-certifier subcommand
#
# This function adds a certifier whose signatures will be used to
# calculate validity of keys used to connect to user accounts on the
# server.  The specified certifier key is first retrieved from the Web
# of Trust with the monkeysphere-user-controlled gpg_sphere keyring.
# Once then new key is retrieved, it is imported into the core
# keyring.  The gpg_core then ltsigns the key with the desired trust
# level, and then the key is exported back to the gpg_sphere keyring.
# The gpg_sphere has ultimate owner trust of the core key, so the core
# ltsigs on the new certifier key can then be used by gpg_sphere
# calculate validity for keys inserted in the authorized_keys file.
#
# This is all to keep the monkeysphere user that connects to the
# keyservers from accessing the core secret key.
#
# 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 2008-2009, and are all released under the GPL,
# version 3 or later.

add_certifier() {

local domain=
local trust=full
local depth=1
local keyID
local fingerprint
local ltsignCommand
local trustval

# get options
while true ; do
    case "$1" in
	-n|--domain)
	    domain="$2"
	    shift 2
	    ;;
	-t|--trust)
	    trust="$2"
	    shift 2
	    ;;
	-d|--depth)
	    depth="$2"
	    shift 2
	    ;;
	-)
	    break
	    ;;
	*)
	    if [ "$(echo "$1" | cut -c 1)" = '-' ] ; then
		failure "Unknown option '$1'.
Type '$PGRM help' for usage."
	    fi
	    break
	    ;;
    esac
done

keyID="$1"

# check that key ID or file is specified
if [ -z "$keyID" ] ; then
    failure "You must specify the key ID of a key to add, or specify a file to read the key from."
fi

# check the trust value
case "$trust" in
    'marginal')
	trustval=1
	;;
    'full')
	trustval=2
	;;
    *)
	failure "Trust value requested ('$trust') was unclear (only 'marginal' or 'full' are supported)."
	;;
esac

# if file is specified
if [ -f "$keyID" -o "$keyID" = '-' ] ; then
    # load the key from stdin
    if [ "$keyID" = '-' ] ; then
	# make a temporary file to hold the key from stdin
	keyID=$(msmktempfile)
	trap "rm -f $keyID" EXIT
	log verbose "reading key from stdin..."
	cat > "$keyID"

    # load the key from the file
    elif [ -f "$keyID" ] ; then
	log verbose "reading key from file '$keyID'..."
    fi

    # check the key is ok as monkeysphere user before loading
    log debug "checking keys in file..."
    fingerprint=$(su_monkeysphere_user \
	"${SYSSHAREDIR}/common" list_primary_fingerprints < "$keyID")

    if [ $(printf "%s" "$fingerprint" | egrep -c '^[A-F0-9]{40}$') -ne 1 ] ; then
	failure "There was not exactly one gpg key in the file."
    fi

    # load the key
    gpg_sphere --import <"$keyID" 2>/dev/null \
	|| failure "could not read key from '$keyID'"

# else, get the key from the keyserver
else
    log verbose "searching keyserver $KEYSERVER for keyID $keyID..."
    gpg_sphere --keyserver "$KEYSERVER" --recv-key "0x${keyID}!" \
	|| failure "Could not receive a key with this ID from the '$KEYSERVER' keyserver."

    # get the full fingerprint of new certifier key
    log debug "getting fingerprint of certifier key..."
    fingerprint=$(gpg_sphere --list-key --with-colons --with-fingerprint "0x${keyID}!" \
	| grep '^fpr:' | cut -d: -f10)

    # test that there is only a single fingerprint
    if (( $(echo "$fingerprint" | wc -l) != 1 )) ; then
	cat <<EOF
More than one fingerprint found:
$fingerprint
Please use a more specific key ID.
EOF
	failure
    fi

    log info "key found:"
    gpg_sphere --fingerprint "0x${fingerprint}!"

    if [ "$PROMPT" != "false" ] ; then
	printf "Are you sure you want to add the above key as a certifier\nof users on this system? (Y/n) " >&2
	read OK; OK=${OK:-Y}
	if [ "${OK/y/Y}" != 'Y' ] ; then
	    failure "Identity certifier not added."
	fi
    else
	log debug "adding key without prompting."
    fi
fi

# export the key to the core keyring so that the core can sign the
# new certifier key
log debug "loading key into core keyring..."
gpg_sphere --export "0x${fingerprint}!" | gpg_core --import

# edit-key script to ltsign key
# NOTE: *all* user IDs will be ltsigned
ltsignCommand="ltsign
y
$trustval
$depth
$domain
y
save"
# end script

# core ltsigns the newly imported certifier key
log debug "executing core ltsign script..."
if echo "$ltsignCommand" | \
    gpg_core --command-fd 0 --edit-key "0x${fingerprint}!" ; then

    # transfer the new sigs back to the sphere keyring
    gpg_core_sphere_sig_transfer

    # update the sphere trustdb
    log debug "updating sphere trustdb..."
    gpg_sphere --check-trustdb 2>&1 | log debug

    log info "Identity certifier added."
else
    failure "Problem adding identify certifier."
fi

}