More cgroup stuff

Signed-off-by: fbt <fbt@fleshless.org>

ssm

@@ -23,6 +23,8 @@ var() {
 						('==') mode=compare;;
 						('=~') mode=regex;;
 
+						('u') mode=includes;;
+
 						(*) die 71 \"Syntax error in \$FUNCNAME!\";;
 					esac
 					shift
@@ -45,6 +47,14 @@ var() {
 							(*) return 0;;
 						esac
 					;;
+
+					(includes)
+						for i in \"\${_var[@]}\"; do
+							[[ \"\$i\" == \"\$*\" ]] && return 0
+						done
+
+						return 1
+					;;
 				esac
 			}; readonly -f \"${varname}\"
 
@@ -90,8 +100,8 @@ svc() {
 
 	# Cgroups
 	if cgroups; then
-		mkdir -p "$cgroup_home/$service_name"
-		echo "$BASHPID" > "$cgroup_home/$service_name/cgroup.procs"
+		mkdir -p "$cgroup_home/$service_cgroup_name"
+		echo "$BASHPID" > "$cgroup_home/$service_cgroup_name/cgroup.procs"
 	fi
 
 	svc::cleanup() {
@@ -292,15 +302,23 @@ read_systemd_service() {
 start() {
 	service_running && return 3
 
-	rm -f "$service_stopped_flag"
-
 	[[ -f "${service_command[0]}" ]] || return 9
 
+	if cgroups; then
+		if service_cgroup_exclusive; then
+			if ! service_cgroup_empty; then
+				return 15
+			fi
+		fi
+	fi
+
 	depend "${service_depends[@]}" || return 7
 	depend_ready "${service_depends_ready[@]}" || return 7
 
 	mktmpfiles || return 13
 
+	rm -f "$service_stopped_flag"
+
 	if service_managed; then
 		if service_respawn; then
 			svc respawn "${service_command[@]}" &
@@ -318,6 +336,12 @@ start() {
 		(( res )) && return "$res"
 		printf '1' > "$service_enabled_flag"
 	else
+		# Put ourselves into the cgroup, so that even when we die, whatever we started stays in it
+		if cgroups; then
+			mkdir -p "$cgroup_home/$service_cgroup_name"
+			echo "$BASHPID" > "$cgroup_home/$service_cgroup_name/cgroup.procs"
+		fi
+
 		exec "${service_command[@]}" 1>"$service_logfile_out" 2>"$service_logfile_err" &
 	fi
 
@@ -350,6 +374,16 @@ stop() {
 		pid_wait "$service_pid" || return 5
 		> "$service_stopped_flag"
 
+		# Cgroup stuff
+		if cgroups; then
+			if service_cgroup_wait; then
+				for p in "${service_cgroup_procs[@]}"; do
+					pid_wait "$p" &
+					wait || return 5
+				done
+			fi
+		fi
+
 		return 0
 	fi
 }
@@ -384,7 +418,14 @@ info() {
 			"PID"      "${service_pid:-none}"
 	fi
 
-	printf "%12s: %s\n" "${_info_items[@]}"
+	# Show the cgroup
+	if cgroups; then
+		_info_items += "Cgroup" "$cgroup_home/$service_cgroup_name" \
+		               "Cgroup procs" "${#service_cgroup_procs[@]}"
+	fi
+
+	printf "%16s: %s\n" "${_info_items[@]}"
+
 }
 
 ## Restart just calls the script twice by default
@@ -427,6 +468,8 @@ var service_pid \
 	service_ready_flag \
 	service_enabled_flag \
 	service_stopped_flag \
+	service_cgroup_name \
+	service_cgroup_procs \
 	cgroup_home \
 	failed_deps \
 	svc_pidfile \
@@ -443,25 +486,31 @@ var XDG_CONFIG_HOME := "$HOME/.config"
 var XDG_RUNTIME_DIR := "/run/user/$UID"
 
 ## Let's set some defaults
+# These are meaningful to reconfigure.
+var service_respawn = 0 # Respawn the service if it exits
+var service_workdir = '/'
+var service_stop_timeout = 30
+var service_ready_timeout = 15
+var service_signals = 1 10 12
+var service_reload_signal = 1
+var service_stop_signal = 15
+var service_cgroup_exclusive = 0 # Refuse to start the service if its cgroup is not empty
+var service_cgroup_wait = 0 # Wait on all the members of the cgroup to exit when stopping the service.
+var systemd = 0 # Enable systemd-related functions.
+var systemd_service_path = /etc/systemd/system /run/systemd/system /lib/systemd/system
+var cgroups = 0 # Enable cgroup-related functions
+var usrdir = '/usr/share/ssm'
+
+# These are not
 var service_managed = 1
-var service_respawn = 0
 var service_oneshot = 0
 var service_running = 0
 var service_enabled = 0
 var service_stopped = 0
 var service_systemd = 0
-var service_workdir = '/'
-var service_stop_timeout = 30
-var service_ready_timeout = 15
-var service_stop_signal = 15
-var service_reload_signal = 1
-var service_signals = 1 10 12
 var service_nologs = 0
-var usrdir = '/usr/share/ssm'
-var systemd = 0
-var systemd_service_path = /etc/systemd/system /run/systemd/system /lib/systemd/system
+var service_cgroup_empty = 1
 var ssm_config = 0
-var cgroups = 0
 
 ## Figure out our full path
 case "$0" in
@@ -588,6 +637,7 @@ service_logfile_err := "$logdir/${service_name}.err.log"
 service_ready_flag := "$rundir/$service_name.ready"
 service_enabled_flag := "$rundir/$service_name.enabled"
 service_stopped_flag := "$rundir/$service_name.stopped"
+service_cgroup_name := "$service_name"
 
 # A shortcut for disabling logging
 if service_nologs; then
@@ -617,6 +667,24 @@ if [[ -f "$service_stopped_flag" ]]; then
 	service_stopped = 1
 fi
 
+# Check cgroups, if enabled
+if cgroups; then
+	if [[ -d "$cgroup_home/$service_cgroup_name" ]]; then
+		while read -r line; do
+			service_cgroup_procs += "$line"
+		done < "$cgroup_home/$service_cgroup_name/cgroup.procs"
+
+		if (( ${#service_cgroup_procs[@]} )); then
+			service_cgroup_empty = 0
+		fi
+	fi
+
+	# If there's a service PID, check if it's in the service's cgroup
+	if service_pid; then
+		service_cgroup_procs u "$service_pid" || die 29 "Recorded service PID is not in the service's cgroup, bailing!"
+	fi
+fi
+
 # Check if action is even defined
 is_function "$2" || die 17 "Function $2 is not defined for $service_name."
 
@@ -651,7 +719,8 @@ case "$2" in
 			5 "Readyness check for $service_name timed out" \
 			7 "Failed to start dependencies for $service_name: ${failed_deps[@]}" \
 			9 "service_command does not exist: ${service_command[0]}" \
-			13 "Failed to create temporary files for $service_name"
+			13 "Failed to create temporary files for $service_name" \
+			15 "Refusing to start $service_name: the service cgroup is not empty and \$service_cgroup_exclusive is set"
 	;;
 
 	reload)