Add support for the s6 supervision suite

7 files changed, 151 insertions, 2 deletions

diff --git a/init.d/Makefile b/init.d/Makefile
index 0bd3651b..a662f8d7 100644
--- a/init.d/Makefile
+++ b/init.d/Makefile
@@ -3,7 +3,7 @@ include ../mk/net.mk
 DIR=	${INITDIR}
 SRCS=	bootmisc.in fsck.in hostname.in local.in localmount.in loopback.in \
 	netmount.in osclock.in root.in savecache.in swap.in swapfiles.in \
-	tmpfiles.setup.in swclock.in sysctl.in urandom.in ${SRCS-${OS}}
+	tmpfiles.setup.in swclock.in sysctl.in urandom.in s6-svscan.in ${SRCS-${OS}}
 BIN=	${OBJS}
 
 # Are we installing our network scripts?
diff --git a/init.d/s6-svscan.in b/init.d/s6-svscan.in
new file mode 100644
index 00000000..6fdf4e1d
--- /dev/null
+++ b/init.d/s6-svscan.in
@@ -0,0 +1,31 @@
+#!@SBINDIR@/openrc-run
+# Copyright (C) 2015 William Hubbs <w.d.hubbs@gmail.com>
+# Released under the 2-clause BSD license.
+
+command=/bin/s6-svscan
+command_args="${RC_SVCDIR}"/s6-scan
+command_background=yes
+pidfile=/var/run/s6-svscan.pid
+
+depend()
+{
+	need localmount
+}
+
+start_pre()
+{
+	einfo "Creating s6 scan directory"
+	checkpath -d -m 0755 "$RC_SVCDIR"/s6-scan
+	return $?
+}
+
+stop_post()
+{
+	ebegin "Stopping any remaining s6 services"
+	s6-svc -dx "${RC_SVCDIR}"/s6-scan/* 2>/dev/null || true
+	eend $?
+
+	ebegin "Stopping any remaining s6 service loggers"
+	s6-svc -dx "${RC_SVCDIR}"/s6-scan/*/log 2>/dev/null || true
+	eend $?
+}
diff --git a/man/openrc-run.8 b/man/openrc-run.8
index f1441525..259d23fc 100644
--- a/man/openrc-run.8
+++ b/man/openrc-run.8
@@ -107,6 +107,18 @@ the service has already been stopped.
 String describing the service.
 .It Ar description_$command
 String describing the extra command.
+.It Ar supervisor
+Supervisor to use to monitor this daemon. If this is unset,
+start-stop-daemon will be used. The only alternate supervisor we support
+in this release is S6 from Skarnet software. To use this, set
+supervisor=s6.
+.It Ar s6_service_path
+The path to the s6 service directory if you are monitoring this service
+with S6. The default is /etc/svc.d/${RC_SVCNAME}.
+.It Ar s6_svwait_options_start
+The options to pass to s6-svwait when starting the service via s6.
+.It Ar s6_svwait_options_stop
+The options to pass to s6-svwait when stopping the service via s6.
 .It Ar start_stop_daemon_args
 List of arguments passed to start-stop-daemon when starting the daemon.
 .It Ar command
diff --git a/s6-guide.md b/s6-guide.md
new file mode 100644
index 00000000..4a37a9cc
--- /dev/null
+++ b/s6-guide.md
@@ -0,0 +1,56 @@
+# Using S6 with OpenRC
+
+Beginning with OpenRC-0.16, we support using the s6 supervision suite
+from Skarmet Software in place of start-stop-daemon for monitoring
+daemons [1].
+
+## Setup
+
+Documenting s6 in detail is beyond the scope of this guide. It will
+document how to set up OpenRC services to communicate with s6.
+
+### Use Default start, stop and status functions
+
+If you write your own start, stop and status functions in your service
+script, none of this will work. You must allow OpenRC to use the default
+functions.
+
+### Dependencies
+
+All OpenRC service scripts that want their daemons monitored by s6
+should have the following line added to their dependencies to make sure
+the s6 scan directory is being monitored.
+
+need s6-svscan
+
+### Variable Settings
+
+The most important setting is the supervisor variable. At the top of
+your service script, you should set this variable as follows:
+
+supervisor=s6
+
+Several other variables affect s6 services. They are documented on the
+openrc-run man page, but I will list them here for convenience:
+
+s6_service_path - the path to the s6 service directory
+s6_svwait_options_start - the options to pass to s6-svwait when starting
+s6_svwait_options_stop - the options to pass to s6-svwait when stopping.
+
+The s6_service_path variable defaults to /etc/svc.d/${RC_SVCNAME} if it
+is not set in the service script. For example, if you want a service
+script called /etc/init.d/foobar to use s6 to monitor its daemon, the s6
+service should be the directory /etc/svc.d/foobar.
+
+See the documentation for s6 for more information about s6 service
+directories.
+
+The s6_svwait_options_* variables set command line options to pass to
+s6-svwait when starting or stopping the s6 service. These can be very
+useful for waiting for s6 services to signal when they are up, timing out
+when an s6 service doesn't come up, etc.
+
+This is very early support, so feel free to file bugs if you have
+issues.
+
+[1] https://www.skarnet.org/software/s6
diff --git a/sh/Makefile b/sh/Makefile
index 3f8881e8..b9b9fb33 100644
--- a/sh/Makefile
+++ b/sh/Makefile
@@ -1,7 +1,7 @@
 DIR=	${LIBEXECDIR}/sh
 SRCS=	init.sh.in functions.sh.in gendepends.sh.in \
 	openrc-run.sh.in rc-functions.sh.in tmpfiles.sh.in ${SRCS-${OS}}
-INC=	rc-mount.sh functions.sh rc-functions.sh start-stop-daemon.sh
+INC=	rc-mount.sh functions.sh rc-functions.sh s6.sh start-stop-daemon.sh
 BIN=	gendepends.sh init.sh openrc-run.sh tmpfiles.sh ${BIN-${OS}}
 
 INSTALLAFTER=	_installafter
diff --git a/sh/openrc-run.sh.in b/sh/openrc-run.sh.in
index 67e47b75..33dc59c5 100644
--- a/sh/openrc-run.sh.in
+++ b/sh/openrc-run.sh.in
@@ -132,6 +132,7 @@ start()
 {
 	local func=ssd_start
 	case "$supervisor" in
+		s6) func=s6_start ;;
 		?*)
 			ewarn "Invalid supervisor, \"$supervisor\", using start-stop-daemon"
 			;;
@@ -143,6 +144,7 @@ stop()
 {
 	local func=ssd_stop
 	case "$supervisor" in
+		s6) func=s6_stop ;;
 		?*)
 			ewarn "Invalid supervisor, \"$supervisor\", using start-stop-daemon"
 			;;
@@ -154,6 +156,7 @@ status()
 {
 	local func=ssd_status
 	case "$supervisor" in
+		s6) func=s6_status ;;
 		?*)
 			ewarn "Invalid supervisor, \"$supervisor\", using start-stop-daemon"
 			;;
@@ -183,6 +186,7 @@ unset _conf_d
 sourcex -e "@SYSCONFDIR@/rc.conf"
 
 # load service supervisor functions
+sourcex "@LIBEXECDIR@/sh/s6.sh"
 sourcex "@LIBEXECDIR@/sh/start-stop-daemon.sh"
 
 # Set verbose mode
diff --git a/sh/s6.sh b/sh/s6.sh
new file mode 100644
index 00000000..780beab2
--- /dev/null
+++ b/sh/s6.sh
@@ -0,0 +1,46 @@
+# Start / stop / status functions for s6 support
+# Copyright (c) 2015 William Hubbs <w.d.hubbs@gmail.com>
+# Released under the 2-clause BSD license.
+
+[ -z "${s6_service_path}" ] && s6_service_path="/etc/svc.d/${RC_SVCNAME}"
+
+s6_start()
+{
+	if [ ! -d "${s6_service_path}" ]; then
+		eerror "${s6_service_path} does not exist."
+ 	return 1
+ fi
+	local rc
+	ebegin "Starting ${name:-$RC_SVCNAME}"
+	ln -sf "${s6_service_path}" "${RC_SVCDIR}"/s6-scan
+	s6-svscanctl -an "${RC_SVCDIR}"/s6-scan
+	rc=$?
+	if [ -n "$s6_svwait_options_start" ]; then
+		s6-svwait ${s6_svwait_options_start} "${s6_service_path}"
+		rc=$?
+	fi
+	eend $rc "Failed to start $RC_SVCNAME"
+}
+
+s6_stop()
+{
+	if [ ! -d "${s6_service_path}" ]; then
+		eerror "${s6_service_path} does not exist."
+ 	return 1
+ fi
+	local rc
+	ebegin "Stopping ${name:-$RC_SVCNAME}"
+	rm -rf "${RC_SVCDIR}/s6-scan/${s6_service_path##*/}"
+	s6-svscanctl -an "${RC_SVCDIR}"/s6-scan
+	rc=$? 
+	if [ -n "$s6_svwait_options_stop" ]; then
+		s6-svwait ${s6_svwait_options_stop} "${s6_service_path}"
+		rc=$?
+	fi
+	eend $rc "Failed to stop $RC_SVCNAME"
+}
+
+s6_status()
+{
+	s6-svstat "${s6_service_path}"
+}