adding sshagent plugin

plugins/available/sshagent.plugin.bash

@@ -0,0 +1,51 @@
+cite about-plugin
+about-plugin 'sshagent helper functions'
+
+function sshagent() {
+	local op=$1
+	case $op in
+	on)
+		if [ -z "$SSH_AGENT_ENV" ]; then
+			export SSH_AGENT_ENV=${HOME}/.ssh/agent_env
+		fi
+		if [ ! -d "${HOME}/.ssh" ]; then
+			mkdir -p "${HOME}/.ssh"
+			restorecon -rv "${HOME}/.ssh"
+		fi
+
+		if [ -r ${SSH_AGENT_ENV} ]; then
+			## do not trust SSH_AGENT_PID
+			agent_pid=$( cat ${SSH_AGENT_ENV} | tail -1 | cut -d' ' -f4 | cut -d';' -f1 )
+			ps --pid ${agent_pid} -opid= &> /dev/null
+			if [ $? -ne 0 ]; then
+				echo "There's a dead ssh-agent at the landing..."
+				rm -f ${SSH_AGENT_ENV}
+			fi
+		fi
+
+		if [ ! -r $SSH_AGENT_ENV ]; then
+		    ssh-agent > ${SSH_AGENT_ENV}
+		fi
+
+		. ${SSH_AGENT_ENV}
+	;;
+	off)
+		if [ -r ${SSH_AGENT_ENV} ]; then
+			## ensure the file indeed points to a really running agend:
+			agent_pid=$( cat ${SSH_AGENT_ENV} | tail -1 | cut -d' ' -f4 | cut -d';' -f1 )
+			ps auxw | grep ${agent_pid} | grep -v grep > /dev/null
+			if [ $? -eq 0 ]; then
+				echo "Killing ssh-agent ..."
+				kill -9 ${agent_pid}
+				rm -f ${SSH_AGENT_ENV}
+			fi
+		fi
+
+	;;
+	*)
+	;;
+	esac
+
+}
+
+sshagent on