bin/rc: Daemonize, add status cmd, and run svcs

And pass old and new session type lists to services instead of list of
added or removed session type and ancestor types.

1 files changed, 183 insertions, 66 deletions

diff --git a/bin/rc b/bin/rc
index 1b6c1cd..277c2aa 100755
--- a/bin/rc
+++ b/bin/rc
@@ -2,12 +2,14 @@
 
 set -eu
 
-RC_MAGIC='~/rc'
+MAGIC='~/rc'
 
 progname=
 rc_fifo=
+res_fifo=
+sessions=','
 
-error()
+info()
 {
 	local fmt="${1}"
 	shift 1
@@ -17,6 +19,16 @@ error()
 	return 0
 }
 
+error()
+{
+	local fmt="${1}"
+	shift 1
+
+	printf "%s: Error: ${fmt}\n" "${progname}" "${@}" 1>&2
+
+	return 0
+}
+
 valid_session_type()
 {
 	local session_type="${1}"
@@ -28,59 +40,97 @@ valid_session_type()
 	return 0
 }
 
-# Returns 0 if the session is the first of its type or was last of its type
-# TODO: Handle decrement from 0.
-inc_session()
+run_services()
 {
-	local s_type="${1}"
-	local dir=${2}
-	shift 2
-	local ret=
-
-	ret=1
-
-	s_type="$(printf '%s' "${s_type}" | tr ':' '_')"
-	eval "[ \${sessions_${s_type}:-0} -eq 0 ] && ret=0"
-	eval "sessions_${s_type}=\$((\${sessions_${s_type}:-0} + ${dir}))"
-	eval "[ \${sessions_${s_type}} -eq 0 ] && ret=0"
-
-	return ${ret}
-}
-
-chg_session()
-{
-	local session_type="${1}"
-	local inc_dir=${2}
-	local diff="${3}"
-	shift 3
+	local old_sessions="${1}"
+	local new_sessions="${1}"
+	shift 1
+	local service_script=
 
-	while :; do
-		case "${session_type}" in *:*);; *) break;; esac
-		if inc_session "${session_type}" ${inc_dir}; then
-			diff="${diff}${session_type},"
-		fi
-		session_type="${session_type%:*}"
+	for service_script in "${XDG_CACHE_HOME:-${HOME}/.cache}/homerc/"*; do
+		"$(dirname ${0})/svc" "${service_script##*/}" \
+			"${old_sessions};${new_sessions}"
 	done
-
-	diff="${diff%,}"
 }
 
 beg_session()
 {
 	local session_type="${1}"
 	shift 1
+	local s_type=
+	local add=
+	local new_sessions=
+	local old_sessions=
+
+	s_type="$(printf '%s' "${session_type}" | tr ':' '_')"
+
+	if eval "[ \${sessions_${s_type}:-0} -eq 0 ]"; then
+		add=true
+	else
+		add=false
+	fi
+
+	# Increment.
+	eval "sessions_${s_type}=\$((\${sessions_${s_type}:-0} + 1))"
 
-	chg_session "${session_type}" 1 '+'
-	return ${?}
+	if ${add}; then
+		new_sessions="${sessions}${session_type},"
+		old_sessions="${sessions}"
+		sessions="${new_sessions}"
+		run_services "${old_sessions}" "${new_sessions}"
+		return ${?}
+	fi
+
+	return 0
 }
 
 end_session()
 {
 	local session_type="${1}"
 	shift 1
+	local s_type=
+	local new_sessions=
+	local old_sessions=
 
-	chg_session "${session_type}" -1 '-'
-	return ${?}
+	s_type="$(printf '%s' "${session_type}" | tr ':' '_')"
+
+	if eval "[ \${sessions_${s_type}:-0} -eq 0 ]"; then
+		error 'No running sessions of type %s' "${session_type}"
+		return 1
+	fi
+
+	# Decrement.
+	eval "sessions_${s_type}=\$((\${sessions_${s_type}} - 1))"
+
+	if eval "[ \${sessions_${s_type}} -eq 0 ]"; then
+		eval "unset sessions_${s_type}"
+		new_sessions="${sessions%,${session_type},*}"
+		new_sessions="${new_sessions},${sessions#*,${session_type},}"
+		old_sessions="${sessions}"
+		sessions="${new_sessions}"
+		run_services "${old_sessions}" "${new_sessions}"
+		return ${?}
+	fi
+
+	return 0
+}
+
+list_sessions()
+{
+	local printed=
+	local session=
+
+	printed=false
+	IFS=','
+	for session in ${sessions}; do
+		unset IFS
+		if ${printed}; then
+			printf ', '
+		fi
+		eval "printf '%s (%d)' '${session}' \${sessions_${session}}"
+		printed=true
+	done
+	unset IFS
 }
 
 listen()
@@ -91,43 +141,72 @@ listen()
 
 	while :; do
 		if read -r magic cmd arg; then
-			case "${magic}" in "${RC_MAGIC}");; *)
+			case "${magic}" in "${MAGIC}");; *)
 				continue
 			esac
+			case "${cmd}" in
+				'beg')
+					if valid_session_type "${arg}"; then
+						beg_session "${arg}"
+					fi
+					;;
+				'end')
+					if valid_session_type "${arg}"; then
+						end_session "${arg}"
+					fi
+					;;
+				'who')
+					{
+						printf '%s ' "${MAGIC}"
+						list_sessions
+						printf '\n'
+					} 1>"${arg}"
+					;;
+				'bye')
+					break
+					;;
+				*)
+					continue
+					;;
+			esac
 		fi
-		case "${cmd}" in
-			'beg')
-				if valid_session_type "${arg}"; then
-					beg_session "${arg}"
-				fi
-				;;
-			'end')
-				if valid_session_type "${arg}"; then
-					end_session "${arg}"
-				fi
-				;;
-			'bye')
-				break
-				;;
-			*)
-				continue
-				;;
-		esac
 	done 0<"${rc_fifo}"
 }
 
+run_daemon()
+{
+	local session_type="${1}"
+	shift 1
+	local piddir=
+
+	exec 0<&- 1>&- 2>&-
+	# TODO:
+	# Disassociate from its process group (usually a shell), to insulate
+	# itself from signals (such as HUP) sent to the process group
+	# Ignore all terminal I/O signals
+
+	piddir="${XDG_CACHE_HOME:-${HOME}/.cache}/homerc"
+	mkdir -p "${piddir}"
+	rm -f "${piddir}/"*
+
+	beg_session "${session_type}"
+	listen
+	rm "${rc_fifo}"
+	rm -f "${piddir}/"*
+
+	return 0
+}
+
 start()
 {
 	local session_type="${1}"
 	shift 1
 
-	if mkfifo "${rc_fifo}" 2>/dev/null; then
-		beg_session "${session_type}"
-		listen
-		rm "${rc_fifo}"
+	if mkfifo -m 0600 "${rc_fifo}" 2>/dev/null; then
+		run_daemon "${session_type}" &
 	else
 		# Signal the running rc daemon.
-		printf "%s beg %s\n" "${RC_MAGIC}" "${session_type}" \
+		printf "%s beg %s\n" "${MAGIC}" "${session_type}" \
 			1>"${rc_fifo}"
 	fi
 
@@ -139,24 +218,58 @@ stop()
 	local session_type="${1}"
 	shift 1
 
-	if mkfifo "${rc_fifo}" 2>/dev/null; then
-		# Assuming the daemon role just to end a non-existent session
-		# makes no sense.
+	if mkfifo -m 0600 "${rc_fifo}" 2>/dev/null; then
+		# Daemonizing just to end a non-existent session makes no sense.
 		error 'No running daemon found'
 		rm "${rc_fifo}"
 		return 1
 	else
 		# Signal the running rc daemon.
-		printf "%s end %s\n" "${RC_MAGIC}" "${session_type}" \
+		printf "%s end %s\n" "${MAGIC}" "${session_type}" \
 			1>"${rc_fifo}"
 	fi
 
 	return 0
 }
 
+status()
+{
+	local magic=
+	local list=
+
+	if mkfifo -m 0600 "${rc_fifo}" 2>/dev/null; then
+		# Daemonizing just to list non-existent sessions makes no sense.
+		error 'No running daemon found'
+		rm "${rc_fifo}"
+		return 1
+	else
+		# Establish response FIFO.
+		if ! mkfifo -m 0600 "${res_fifo}" 2>/dev/null; then
+			error 'Failed to communicate with running daemon'
+			return 1
+		fi
+		# Signal the running rc daemon.
+		printf "%s who %s\n" "${MAGIC}" "${res_fifo}" \
+			1>"${rc_fifo}"
+		if read -r magic list; then
+			case "${magic}" in "${MAGIC}");; *)
+				continue
+			esac
+			info 'Sessions: %s' "${list}"
+		else
+			error 'Failed to communicate with running daemon'
+			rm "${res_fifo}"
+			return 1
+		fi
+	fi
+
+	return 0
+}
+
 usage()
 {
 	printf 'Usage: %s {start|stop} <session-type>\n' "${0}"
+	printf '   or: %s status\n' "${0}"
 
 	return 0
 }
@@ -180,6 +293,7 @@ main()
 
 	progname="${0##*/}"
 	rc_fifo="/tmp/homercrc-$(id -u)"
+	res_fifo="/tmp/homercres-${$}"
 
 	case "${action}" in
 		'start')
@@ -188,6 +302,9 @@ main()
 		'stop')
 			stop "${session_type}"
 			;;
+		'status')
+			status
+			;;
 		*)
 			usage 1>&2
 			return 1