Use the sinit conventions for init

This should make it easier to switch out `init` for other versions,
although the `getty` config still needs to be removed.

- use `/bin/rc.init` for start
- use `rc.shutdown` for stop
- make `rc.init` run other code.
- merge `containers` and `containerd` startup code

Signed-off-by: Justin Cormack <justin.cormack@docker.com>

pkg/init/Dockerfile

@@ -12,3 +12,4 @@ WORKDIR /
 COPY --from=mirror /out/ /
 COPY init /
 COPY etc etc/
+COPY bin bin/

pkg/init/bin/rc.init

@@ -110,3 +110,10 @@ mount --make-rshared /var
 
 # make / rshared
 mount --make-rshared /
+
+# execute other init processes
+INITS="$(find /etc/init.d -type f | sort)"
+for f in $INITS
+do
+	$f &
+done

pkg/init/bin/rc.shutdown

@@ -0,0 +1,13 @@
+#!/bin/sh
+
+[ "$1" = "reboot" ] && exec /sbin/reboot
+
+# poweroff
+
+/usr/sbin/killall5 -15
+/bin/sleep 5
+/usr/sbin/killall5 -9
+/sbin/swapoff -a
+/bin/echo "Unmounting filesystems"
+/bin/umount -a -r
+/sbin/poweroff -f

pkg/init/etc/init.d/010-containerd

@@ -1,5 +1,19 @@
 #!/bin/sh
 
+# set global ulimits TODO move to /etc/limits.conf
+ulimit -n 1048576
+ulimit -p unlimited
+
+# bring up containerd
+printf "\nStarting containerd\n"
+/usr/bin/containerd &
+
+# wait for socket to be there
+while [ ! -S /run/containerd/containerd.sock ]
+do
+	sleep 0.1
+done
+
 # start onboot containers, run to completion
 
 if [ -d /containers/onboot ]

pkg/init/etc/init.d/containerd

@@ -1,9 +0,0 @@
-#!/bin/sh
-
-# bring up containerd
-ulimit -n 1048576
-ulimit -p unlimited
-
-printf "\nStarting containerd\n"
-mkdir -p /var/log
-exec /usr/bin/containerd

pkg/init/etc/inittab

@@ -1,15 +1,9 @@
 # /etc/inittab
 
-::sysinit:/etc/init.d/rcS
+::sysinit:/bin/rc.init
-::once:/etc/init.d/containerd
-::once:/etc/init.d/containers
 
 # Stuff to do for the 3-finger salute
-::ctrlaltdel:/sbin/reboot
+::ctrlaltdel:/bin/rc.shutdown reboot
 
-# Stuff to do before rebooting
+# Stuff to do on shutdown
-::shutdown:/usr/sbin/killall5 -15
+::shutdown:/bin/rc.shutdown poweroff
-::shutdown:/bin/sleep 5
-::shutdown:/usr/sbin/killall5 -9
-::shutdown:/bin/echo "Unmounting filesystems"
-::shutdown:/bin/umount -a -r