modulecmd: block loading of a module on dedicated systems

Pmodules/modulecmd.bash.in

@@ -271,6 +271,13 @@ die_removing_collection_failed(){
 		 "${CMD}" "${subcommand}" \
 		 "cannot remove collection" "$1"
 }
+
+die_is_blocked(){
+	std::die 3 "%s %s: %s -- %s" \
+		 "${CMD}" "${subcommand}" \
+		 "module is blocked on this system" "$1"
+}
+
 #
 # get release stage of module
 # Note:
@@ -598,6 +605,30 @@ subcommand_load() {
 		g_env_must_be_saved='yes'
 	}
 
+	is_blocked() {
+		: "
+		test whether a module is blocked or not.
+
+		args:
+			$1: prefix of module
+
+		exit codes:
+			0: if blocked
+			1: otherwise
+		"
+		local _prefix="$1"
+		test -e "${_prefix}/.blocklist" || return 1 # not blocked!
+		local _pattern='//'
+		while read line; do
+			_pattern+=' && !'"/${line}/"
+		done < "${_prefix}/.blocklist"
+		local out=$(awk "${_pattern}"' {print $0}' <<< "${HOSTNAME}")
+		[[ -z "${out}" ]] || return 1  # not blocked!
+		[[ -r "${_prefix}/.blockmsg" ]] || return 0
+		cat "${_prefix}/.blockmsg" 1>&2
+		return 0
+	}
+
 	#......................................................................
 	local args=()
 	local opts=()
@@ -721,6 +752,7 @@ subcommand_load() {
 			die_not_a_modulefile "${m}"
 		local prefix=''
 		get_module_prefix prefix "${current_modulefile}"
+		is_blocked "${prefix}" && die_is_blocked "${m}"
                 if [[ -n ${prefix} ]]; then
                         test -r "${prefix}/.info" && cat "$_" 1>&2
 			test -r "${prefix}/.dependencies" && load_dependencies "$_"