Add a wrapper for using cassh with a keyfile

Makefile

@@ -24,7 +24,7 @@ V =	0
 PREFIX =	/usr/local
 MANPREFIX =	${PREFIX}/man
 
-BIN =	cassh
+BIN =	cassh cassh-keyfile
 MAN1 =	${BIN:=.1}
 SRC =	${BIN:=.sh} ${MAN1}
 

cassh-keyfile.1

@@ -0,0 +1,64 @@
+.\" cassh - Manager for an OpenSSH Certification Authority
+.\"
+.\" Written in 2022 by Lucas
+.\"
+.\" To the extent possible under law, the author(s) have dedicated all
+.\" copyright and related and neighboring rights to this software to the
+.\" public domain worldwide. This software is distributed without any
+.\" warranty.
+.\"
+.\" You should have received a copy of the CC0 Public Domain Dedication
+.\" along with this software. If not, see
+.\" <http://creativecommons.org/publicdomain/zero/1.0/>.
+.\"
+.Dd March 01, 2022
+.Dt CASSH-KEYFILE 1
+.Os
+.Sh NAME
+.Nm cassh-keyfile
+.Nd Wrapper for using a private key file with cassh
+.Sh SYNOPSIS
+.Nm
+.Ar private_key
+.Cm cassh_command
+.Op Ar options ...
+.Sh DESCRIPTION
+.Xr cassh 1
+requires a running
+.Xr ssh-agent 1
+with the Certification Authority private key already loaded.
+.Nm
+provides a thin wrapper around
+.Xr cassh 1 ,
+initiating an
+.Xr ssh-agent 1
+instance and loading the Certification Authority private key from
+.Ar private_key
+file before calling
+.Xr cassh 1 .
+The
+.Xr ssh-agent 1
+instance exits when the commands are completed.
+.Pp
+.Nm
+will only instantiate an
+.Xr ssh-agent 1
+if
+.Cm cassh_command
+does need one.
+.Sh EXIT STATUS
+.Ex -std
+.Sh SEE ALSO
+.Xr ssh-agent 1 ,
+.Xr ssh-keygen 1
+.Sh AUTHORS
+.An Lucas
+.Sh LICENSE
+.Nm
+is in the public domain.
+.Pp
+To the extent possible under law, the author(s) have dedicated all
+copyright and related and neighboring rights to this software to the
+public domain worldwide.
+.Pp
+.Lk http://creativecommons.org/publicdomain/zero/1.0/

cassh-keyfile.sh

@@ -0,0 +1,45 @@
+#!/bin/sh
+# cassh - Manager for an OpenSSH Certification Authority
+#
+# Written in 2022 by Lucas
+#
+# To the extent possible under law, the author(s) have dedicated all
+# copyright and related and neighboring rights to this software to the
+# public domain worldwide. This software is distributed without any
+# warranty.
+# You should have received a copy of the CC0 Public Domain Dedication
+# along with this software. If not, see
+# <http://creativecommons.org/publicdomain/zero/1.0/>.
+
+usage()
+{
+	cat - <<EOF >&2
+Usage:
+	${0##*/} private_key cassh_command [options ...]
+EOF
+	exit 1
+}
+
+if [ $# -lt 2 ]; then
+	usage
+fi
+
+cassh_command=$2
+needs_agent=false
+case $cassh_command in
+issue)
+	needs_agent=true
+	;;
+esac
+
+if $needs_agent; then
+	ssh-agent sh -s "$@" <<'EOF'
+ssh-add -q "$1" && shift && cassh "$@"
+rc=$?
+ssh-agent -k >/dev/null
+exit $rc
+EOF
+else
+	shift
+	cassh "$@"
+fi