From f4aacc39f0dc1090b3082c2a445a0ea2e89ac84c Mon Sep 17 00:00:00 2001
From: P. J. McDermott <pj@pehjota.net>
Date: Fri, 01 Jun 2018 19:39:45 -0400
Subject: bin/rc: Ignore SIGHUP and don't halt svc running on error

Fix run_services() parameters, function call error handling, the daemon
printing to the closed standard error FD, a crash due to an empty
session type in the status command, and a crash when given an unwritable
status response file name.  Also document the session type format.
---
diff --git a/bin/rc b/bin/rc
index 277c2aa..e96245c 100755
--- a/bin/rc
+++ b/bin/rc
@@ -43,14 +43,18 @@ valid_session_type()
 run_services()
 {
 	local old_sessions="${1}"
-	local new_sessions="${1}"
-	shift 1
+	local new_sessions="${2}"
+	shift 2
+	local ret=
 	local service_script=
 
+	ret=0
 	for service_script in "${XDG_CACHE_HOME:-${HOME}/.cache}/homerc/"*; do
-		"$(dirname ${0})/svc" "${service_script##*/}" \
-			"${old_sessions};${new_sessions}"
+		"$(dirname "${0}")/svc" "${service_script##*/}" \
+			"${old_sessions};${new_sessions}" || ret=1
 	done
+
+	return ${ret}
 }
 
 beg_session()
@@ -77,8 +81,7 @@ beg_session()
 		new_sessions="${sessions}${session_type},"
 		old_sessions="${sessions}"
 		sessions="${new_sessions}"
-		run_services "${old_sessions}" "${new_sessions}"
-		return ${?}
+		run_services "${old_sessions}" "${new_sessions}" || return 1
 	fi
 
 	return 0
@@ -95,7 +98,7 @@ end_session()
 	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}"
+		# No running sessions of specified type
 		return 1
 	fi
 
@@ -108,8 +111,7 @@ end_session()
 		new_sessions="${new_sessions},${sessions#*,${session_type},}"
 		old_sessions="${sessions}"
 		sessions="${new_sessions}"
-		run_services "${old_sessions}" "${new_sessions}"
-		return ${?}
+		run_services "${old_sessions}" "${new_sessions}" || return 1
 	fi
 
 	return 0
@@ -124,13 +126,16 @@ list_sessions()
 	IFS=','
 	for session in ${sessions}; do
 		unset IFS
+		case "${session}" in '') continue;; esac
 		if ${printed}; then
 			printf ', '
 		fi
-		eval "printf '%s (%d)' '${session}' \${sessions_${session}}"
+		eval "printf '%s (%d)' \"\${session}\" \${sessions_${session}}"
 		printed=true
 	done
 	unset IFS
+
+	return 0
 }
 
 listen()
@@ -141,18 +146,11 @@ listen()
 
 	while :; do
 		if read -r magic cmd arg; then
-			case "${magic}" in "${MAGIC}");; *)
-				continue
-			esac
+			case "${magic}" in "${MAGIC}");; *) continue;; esac
 			case "${cmd}" in
-				'beg')
+				'beg' | 'end')
 					if valid_session_type "${arg}"; then
-						beg_session "${arg}"
-					fi
-					;;
-				'end')
-					if valid_session_type "${arg}"; then
-						end_session "${arg}"
+						"${cmd}_session" "${arg}" || :
 					fi
 					;;
 				'who')
@@ -160,7 +158,7 @@ listen()
 						printf '%s ' "${MAGIC}"
 						list_sessions
 						printf '\n'
-					} 1>"${arg}"
+					} 1>"${arg}" || :
 					;;
 				'bye')
 					break
@@ -171,6 +169,8 @@ listen()
 			esac
 		fi
 	done 0<"${rc_fifo}"
+
+	return 0
 }
 
 run_daemon()
@@ -180,10 +180,7 @@ run_daemon()
 	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
+	trap '' HUP
 
 	piddir="${XDG_CACHE_HOME:-${HOME}/.cache}/homerc"
 	mkdir -p "${piddir}"
@@ -191,6 +188,7 @@ run_daemon()
 
 	beg_session "${session_type}"
 	listen
+
 	rm "${rc_fifo}"
 	rm -f "${piddir}/"*
 
@@ -251,11 +249,10 @@ status()
 		# 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 "${MAGIC}");; *)
-				continue
-			esac
+		if read -r magic list 0<"${res_fifo}" && \
+				[ "x${magic}" = "x${MAGIC}" ]; then
 			info 'Sessions: %s' "${list}"
+			rm "${res_fifo}"
 		else
 			error 'Failed to communicate with running daemon'
 			rm "${res_fifo}"
@@ -269,40 +266,36 @@ status()
 usage()
 {
 	printf 'Usage: %s {start|stop} <session-type>\n' "${0}"
-	printf '   or: %s status\n' "${0}"
+	printf '   or: %s status\n\n' "${0}"
+	printf '<session-type> is one or more strings of alphanumeric '
+	printf 'characters\nseparated by colons.\n'
 
 	return 0
 }
 
 main()
 {
-	local action=
-	local session_type=
-
-	if [ ${#} -ne 2 ]; then
-		usage 1>&2
-		return 1
-	fi
-	action="${1}"
-	session_type="${2}"
-
-	if ! valid_session_type; then
-		error 'Invalid session type'
-		return 1
-	fi
+	local action="${1-}"
+	local session_type="${2-}"
 
 	progname="${0##*/}"
 	rc_fifo="/tmp/homercrc-$(id -u)"
 	res_fifo="/tmp/homercres-${$}"
 
 	case "${action}" in
-		'start')
-			start "${session_type}"
-			;;
-		'stop')
-			stop "${session_type}"
+		'start' | 'stop')
+			if [ ${#} -ne 2 ] || valid_session_type \
+					"${session_type}"; then
+				usage 1>&2
+				return 1
+			fi
+			"${action}" "${session_type}"
 			;;
 		'status')
+			if [ ${#} -ne 1 ]; then
+				usage 1>&2
+				return 1
+			fi
 			status
 			;;
 		*)
--
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