+function subkey_to_ssh_agent() {
+ # try to add all authentication subkeys to the agent:
+
+ local authsubkeys
+ local secretkeys
+ local subkey
+ local workingdir
+ local kname
+
+ # get list of secret keys (to work around https://bugs.g10code.com/gnupg/issue945):
+ secretkeys=$(gpg --list-secret-keys --with-colons --fixed-list-mode --fingerprint | grep '^fpr:' | cut -f10 -d: | awk '{ print "0x" $1 "!" }')
+
+ authsubkeys=$(gpg --list-secret-keys --with-colons --fixed-list-mode --fingerprint --fingerprint $secretkeys | cut -f1,5,10,12 -d: | grep -A1 '^ssb:[^:]*::[^:]*a[^:]*$' | grep '^fpr::' | cut -f3 -d: | sort -u)
+
+ workingdir=$(mktemp -d)
+ umask 077
+ mkfifo "$workingdir/passphrase"
+
+ # FIXME: we're currently allowing any other options to get passed
+ # through to ssh-add. should we limit it to known ones? For
+ # example: -d or -c and/or -t <lifetime>
+
+ # FIXME: how do we know if we succeeded or failed? ssh-add gives
+ # weird return values under setsid, and if there are more than one
+
+ for subkey in $authsubkeys; do
+ kname="MonkeySphere Key $subkey"
+
+ if [ "$1" = '-d' ]; then
+ # we're removing the subkey:
+ gpg --export "0x${subkey}!" | openpgp2ssh "$subkey" > "$workingdir/$kname"
+ (cd "$workingdir" && ssh-add -d "$kname")
+ else
+ # we're adding the subkey:
+ mkfifo "$workingdir/$kname"
+ gpg --quiet --passphrase-fd 3 3<"$workingdir/passphrase" \
+ --export-options export-reset-subkey-passwd,export-minimal,no-export-attributes \
+ --export-secret-subkeys "0x${subkey}!" | openpgp2ssh "$subkey" > "$workingdir/$kname" &
+ (cd "$workingdir" && unset -v DISPLAY && unset -v SSH_ASKPASS && /usr/bin/setsid ssh-add "$@" "$kname" </dev/null )&
+
+ passphrase_prompt "Enter passphrase for MonkeySphere Key $subkey: " "$workingdir/passphrase"
+ wait
+ fi
+ rm -f "$workingdir/$kname"
+ done
+
+ rm -rf "$workingdir"
+}
+