+# generate a subkey with the 'a' usage flags set
+gen_subkey(){
+ local keyLength
+ local keyExpire
+ local keyID
+ local gpgOut
+ local userID
+
+ # set default key parameter values
+ keyLength=
+ keyExpire=
+
+ # get options
+ TEMP=$(getopt -o l:e: -l length:,expire: -n "$PGRM" -- "$@")
+
+ if [ $? != 0 ] ; then
+ exit 1
+ fi
+
+ # Note the quotes around `$TEMP': they are essential!
+ eval set -- "$TEMP"
+
+ while true ; do
+ case "$1" in
+ -l|--length)
+ keyLength="$2"
+ shift 2
+ ;;
+ -e|--expire)
+ keyExpire="$2"
+ shift 2
+ ;;
+ --)
+ shift
+ ;;
+ *)
+ break
+ ;;
+ esac
+ done
+
+ if [ -z "$1" ] ; then
+ # find all secret keys
+ keyID=$(gpg --with-colons --list-secret-keys | grep ^sec | cut -f5 -d:)
+ # if multiple sec keys exist, fail
+ if (( $(echo "$keyID" | wc -l) > 1 )) ; then
+ echo "Multiple secret keys found:"
+ echo "$keyID"
+ failure "Please specify which primary key to use."
+ fi
+ else
+ keyID="$1"
+ fi
+ if [ -z "$keyID" ] ; then
+ failure "You have no secret key available. You should create an OpenPGP
+key before joining the monkeysphere. You can do this with:
+ gpg --gen-key"
+ fi
+
+ # get key output, and fail if not found
+ gpgOut=$(gpg --quiet --fixed-list-mode --list-secret-keys --with-colons \
+ "$keyID") || failure
+
+ # fail if multiple sec lines are returned, which means the id
+ # given is not unique
+ if [ $(echo "$gpgOut" | grep '^sec:' | wc -l) -gt '1' ] ; then
+ failure "Key ID '$keyID' is not unique."
+ fi
+
+ # prompt if an authentication subkey already exists
+ if echo "$gpgOut" | egrep "^(sec|ssb):" | cut -d: -f 12 | grep -q a ; then
+ echo "An authentication subkey already exists for key '$keyID'."
+ read -p "Are you sure you would like to generate another one? (y/N) " OK; OK=${OK:N}
+ if [ "${OK/y/Y}" != 'Y' ] ; then
+ failure "aborting."
+ fi
+ fi
+
+ # set subkey defaults
+ # prompt about key expiration if not specified
+ if [ -z "$keyExpire" ] ; then
+ cat <<EOF
+Please specify how long the key should be valid.
+ 0 = key does not expire
+ <n> = key expires in n days
+ <n>w = key expires in n weeks
+ <n>m = key expires in n months
+ <n>y = key expires in n years
+EOF
+ while [ -z "$keyExpire" ] ; do
+ read -p "Key is valid for? (0) " keyExpire
+ if ! test_gpg_expire ${keyExpire:=0} ; then
+ echo "invalid value"
+ unset keyExpire
+ fi
+ done
+ elif ! test_gpg_expire "$keyExpire" ; then
+ failure "invalid key expiration value '$keyExpire'."
+ fi
+
+ # generate the list of commands that will be passed to edit-key
+ editCommands=$(cat <<EOF
+addkey
+7
+S
+E
+A
+Q
+$keyLength
+$keyExpire
+save
+EOF
+)
+
+ log "generating subkey..."
+ fifoDir=$(mktemp -d)
+ (umask 077 && mkfifo "$fifoDir/pass")
+ echo "$editCommands" | gpg --passphrase-fd 3 3< "$fifoDir/pass" --expert --command-fd 0 --edit-key "$keyID" &
+
+ if [ "$DISPLAY" ] && which ssh-askpass >/dev/null; then
+ ssh-askpass "Please enter your passphrase for $keyID: " > "$fifoDir/pass"
+ else
+ read -s -p "Please enter your passphrase for $keyID: " PASS
+ echo "$PASS" > "$fifoDir/pass"
+ fi
+ rm -rf "$fifoDir"
+ wait
+ log "done."
+}
+