update hack/dind for 1.8 mounting of cgroups

Signed-off-by: Jessica Frazelle <acidburn@docker.com>

hack/dind

@@ -13,16 +13,79 @@ set -e
 # apparmor sucks and Docker needs to know that it's in a container (c) @tianon
 export container=docker
 
-# First, make sure that cgroups are mounted correctly.
-CGROUP=/cgroup
+# as of docker 1.8, cgroups will be mounted in the container
+if ! mountpoint -q /sys/fs/cgroup; then
 
-mkdir -p "$CGROUP"
+	# First, make sure that cgroups are mounted correctly.
+	CGROUP=/cgroup
 
-if ! mountpoint -q "$CGROUP"; then
-	mount -n -t tmpfs -o uid=0,gid=0,mode=0755 cgroup $CGROUP || {
-		echo >&2 'Could not make a tmpfs mount. Did you use --privileged?'
-		exit 1
-	}
+	mkdir -p "$CGROUP"
+
+	if ! mountpoint -q "$CGROUP"; then
+		mount -n -t tmpfs -o uid=0,gid=0,mode=0755 cgroup $CGROUP || {
+			echo >&2 'Could not make a tmpfs mount. Did you use --privileged?'
+			exit 1
+		}
+	fi
+
+	# Mount the cgroup hierarchies exactly as they are in the parent system.
+	for HIER in $(cut -d: -f2 /proc/1/cgroup); do
+
+		# The following sections address a bug which manifests itself
+		# by a cryptic "lxc-start: no ns_cgroup option specified" when
+		# trying to start containers within a container.
+		# The bug seems to appear when the cgroup hierarchies are not
+		# mounted on the exact same directories in the host, and in the
+		# container.
+
+		SUBSYSTEMS="${HIER%name=*}"
+
+		# If cgroup hierarchy is named(mounted with "-o name=foo") we
+		# need to mount it in $CGROUP/foo to create exect same
+		# directoryes as on host. Else we need to mount it as is e.g.
+		# "subsys1,subsys2" if it has two subsystems
+
+		# Named, control-less cgroups are mounted with "-o name=foo"
+		# (and appear as such under /proc/<pid>/cgroup) but are usually
+		# mounted on a directory named "foo" (without the "name=" prefix).
+		# Systemd and OpenRC (and possibly others) both create such a
+		# cgroup. So just mount them on directory $CGROUP/foo.
+
+		OHIER=$HIER
+		HIER="${HIER#*name=}"
+
+		mkdir -p "$CGROUP/$HIER"
+
+		if ! mountpoint -q "$CGROUP/$HIER"; then
+			mount -n -t cgroup -o "$OHIER" cgroup "$CGROUP/$HIER"
+		fi
+
+		# Likewise, on at least one system, it has been reported that
+		# systemd would mount the CPU and CPU accounting controllers
+		# (respectively "cpu" and "cpuacct") with "-o cpuacct,cpu"
+		# but on a directory called "cpu,cpuacct" (note the inversion
+		# in the order of the groups). This tries to work around it.
+
+		if [ "$HIER" = 'cpuacct,cpu' ]; then
+			ln -s "$HIER" "$CGROUP/cpu,cpuacct"
+		fi
+
+		# If hierarchy has multiple subsystems, in /proc/<pid>/cgroup
+		# we will see ":subsys1,subsys2,subsys3,name=foo:" substring,
+		# we need to mount it to "$CGROUP/foo" and if there were no
+		# name to "$CGROUP/subsys1,subsys2,subsys3", so we must create
+		# symlinks for docker daemon to find these subsystems:
+		# ln -s $CGROUP/foo $CGROUP/subsys1
+		# ln -s $CGROUP/subsys1,subsys2,subsys3 $CGROUP/subsys1
+
+		if [ "$SUBSYSTEMS" != "${SUBSYSTEMS//,/ }" ]; then
+			SUBSYSTEMS="${SUBSYSTEMS//,/ }"
+			for SUBSYS in $SUBSYSTEMS
+			do
+				ln -s "$CGROUP/$HIER" "$CGROUP/$SUBSYS"
+			done
+		fi
+	done
 fi
 
 if [ -d /sys/kernel/security ] && ! mountpoint -q /sys/kernel/security; then
@@ -32,65 +95,6 @@ if [ -d /sys/kernel/security ] && ! mountpoint -q /sys/kernel/security; then
 	}
 fi
 
-# Mount the cgroup hierarchies exactly as they are in the parent system.
-for HIER in $(cut -d: -f2 /proc/1/cgroup); do
-
-	# The following sections address a bug which manifests itself
-	# by a cryptic "lxc-start: no ns_cgroup option specified" when
-	# trying to start containers within a container.
-	# The bug seems to appear when the cgroup hierarchies are not
-	# mounted on the exact same directories in the host, and in the
-	# container.
-
-	SUBSYSTEMS="${HIER%name=*}"
-
-	# If cgroup hierarchy is named(mounted with "-o name=foo") we
-	# need to mount it in $CGROUP/foo to create exect same
-	# directoryes as on host. Else we need to mount it as is e.g.
-	# "subsys1,subsys2" if it has two subsystems
-
-	# Named, control-less cgroups are mounted with "-o name=foo"
-	# (and appear as such under /proc/<pid>/cgroup) but are usually
-	# mounted on a directory named "foo" (without the "name=" prefix).
-	# Systemd and OpenRC (and possibly others) both create such a
-	# cgroup. So just mount them on directory $CGROUP/foo.
-
-	OHIER=$HIER
-	HIER="${HIER#*name=}"
-
-	mkdir -p "$CGROUP/$HIER"
-
-	if ! mountpoint -q "$CGROUP/$HIER"; then
-		mount -n -t cgroup -o "$OHIER" cgroup "$CGROUP/$HIER"
-	fi
-
-	# Likewise, on at least one system, it has been reported that
-	# systemd would mount the CPU and CPU accounting controllers
-	# (respectively "cpu" and "cpuacct") with "-o cpuacct,cpu"
-	# but on a directory called "cpu,cpuacct" (note the inversion
-	# in the order of the groups). This tries to work around it.
-
-	if [ "$HIER" = 'cpuacct,cpu' ]; then
-		ln -s "$HIER" "$CGROUP/cpu,cpuacct"
-	fi
-
-	# If hierarchy has multiple subsystems, in /proc/<pid>/cgroup
-	# we will see ":subsys1,subsys2,subsys3,name=foo:" substring,
-	# we need to mount it to "$CGROUP/foo" and if there were no
-	# name to "$CGROUP/subsys1,subsys2,subsys3", so we must create
-	# symlinks for docker daemon to find these subsystems:
-	# ln -s $CGROUP/foo $CGROUP/subsys1
-	# ln -s $CGROUP/subsys1,subsys2,subsys3 $CGROUP/subsys1
-
-	if [ "$SUBSYSTEMS" != "${SUBSYSTEMS//,/ }" ]; then
-		SUBSYSTEMS="${SUBSYSTEMS//,/ }"
-		for SUBSYS in $SUBSYSTEMS
-		do
-			ln -s "$CGROUP/$HIER" "$CGROUP/$SUBSYS"
-		done
-	fi
-done
-
 # Note: as I write those lines, the LXC userland tools cannot setup
 # a "sub-container" properly if the "devices" cgroup is not in its
 # own hierarchy. Let's detect this and issue a warning.