Revised pretend-boot description

[rrq/subhost.git] / control

diff --git a/control b/control
index 28a4d2c0d99d9fb2653b4c49d8e1d78d4100595a..304c93bd1400b6a310f17c8e90288d5594b3cc83 100755 (executable)
--- a/control
+++ b/control
@@ -6,6 +6,8 @@
 # $2 = the sub-host to start or stop
 # $3... = the optional chroot-ed command (/startup by default)
 
+set -x
+
 SCRIPT=$0
 CMD=$1
 NAME=$2
@@ -18,64 +20,126 @@ usage() {
 
 [ -z "$NAME" ] && usage
 
-: ${ATTIC=/opt/srv}
-: ${BRIDGE=srv_br}
-: ${TARGET=/srv/$NAME}
-: ${LOWER=$ATTIC/daedalus.fs}
-: ${IMAGE=$ATTIC/$NAME/$NAME.img}
-: ${UPPER=$ATTIC/$NAME/root}
-: ${WORK=$ATTIC/$NAME/work}
-: ${MOUNT=$ATTIC/$NAME/mnt}
+: ${SUBHOST=/opt/subhost}
+: ${OSROOT=}
+: ${TOP=$SUBHOST/$NAME}
+: ${TARGET=$TOP/live}
+: ${IMAGE=$TOP/$NAME.img}
+: ${UPPER=$TOP/root}
+: ${WORK=$TOP/work}
+: ${MOUNT=$TOP/mnt}
 : ${NSNAME=$NAME}
-: ${NETH=1}
+: ${BRIDGES=lan_br}
+: ${CONFIG=$TOP/config}
+
+[ -e "$CONFIG" ] && . "$CONFIG"
 
+cd "$SUBHOST" || exit 1
+
+# Create a simple overlay subhost without its own image file
 create_subhost() {
     mkdir -p $TARGET $MOUNT $UPPER $WORK
+    [ -d "$OSROOT" ] || OSROOT=$SUBHOST/chimaera/base
+    [ -e $CONFIG ] || cat <<EOF > "$CONFIG"
+# Subhost $NAME is an autogenerated overlay subhost with shared filesystem
+OSROOT="$OSROOT"
+BRIDGES="$BRIDGES"
+EOF
 }
 
-setup_network() {
-    if [ -n "$BRIDGE" ] ; then
-       brctl show $BRIDGE >& /dev/null || brctl addbr $BRIDGE
-    fi
+# Generate a mac address for given arguments pass through 40-bit b2sum
+# and with 02: prefix.
+macaddr() {
+    local V="$(b2sum -l 40 <<< "$*" )"
+    V="$( sed 's/\(..\)/\1:/g' <<< "${V}aaaaaaaaaa")"
+    echo "02:${V:0:14}"
+}
 
+# setup the subhost network namespace and link up the host side
+setup_network() {
     E=0
     ip netns add $NSNAME
-    for I in $(eval echo "{1..$NETH}") ; do
+    for BRIDGE in ${BRIDGES[@]} ; do
        IF=$NAME$E
-       ip link add $IF type veth peer name eth$E netns $NSNAME
+       B=( ${BRIDGE/:/ } )
+       BRIDGE="${B[0]}"
+       MAC="${B[1]}"
+       [ -z "$MAC" ] && MAC="$(macaddr "$(hostname)" "$NAME" "$IF")"
+       brctl show $BRIDGE >& /dev/null || brctl addbr $BRIDGE
+       ip link add $IF type veth peer name eth$E address $MAC netns $NSNAME 
        ip link set $IF up
        [ -n "$BRIDGE" ] && brctl addif $BRIDGE $IF
        E=$((E+1))
     done
 }
 
+# check if $1 is mounted
+is_mounted() {
+    grep -qE "^[^ ]+ $1 " /proc/mounts
+}
+
+# Setup or re-setup the subhost filesystem
 setup_rootfs() {
-    if [ -e "$IMAGE" ] ; then
-       mount $IMAGE $MOUNT || exit 1
-       LOWER=$MOUNT/root
-       WORK=$MOUNT/work
+    if is_mounted $TARGET ; then
+       mount -oremount $TARGET
+    else
+       if [ -e "$IMAGE" ] ; then
+           # $IMAGE is either an image file or a link to a partition,
+           # with /root and /work in it.
+           is_mounted $MOUNT || mount $IMAGE $MOUNT || exit 1
+           UPPER=$MOUNT/root
+           WORK=$MOUNT/work
+       fi
+       if [ -z "$OSROOT" ] ; then
+           # No overlay
+           mount --rbind $UPPER $TARGET
+       else
+           # overlay of $UPPER (+$WORK) over $OSROOT onto $TARGET
+           mount -t overlay $NAME \
+                 -olowerdir=$OSROOT,upperdir=$UPPER,workdir=$WORK \
+                 $TARGET
+       fi
     fi
-    mount -t overlay $NAME -olowerdir=$LOWER,upperdir=$UPPER,workdir=$WORK \
-         $TARGET
+}
+
+# Set up cgroup CPU accounting (cpuacct)
+accounting() {
+        # 1-- once, system wide
+        grep -q "/sys/fs/cgroup cgroup" /proc/mounts || \
+            mount -t cgroup -ocpuacct none /sys/fs/cgroup
+        if [ -d /sys/fs/cgroup/$NAME ] ; then
+            : # reset?
+        else
+            mkdir /sys/fs/cgroup/$NAME
+           # the following fixes things that sometimes are broken?
+           for f in cpuset.mems cpuset.cpus ; do
+               [ -z "$(cat /sys/fs/cgroups/$NAME/$F)" ] && \
+                   echo 0 > /sys/fs/cgroups/$NAME/$F
+           done
+
+        fi
+       # Register this task for subhost accounting
+        echo $$ > /sys/fs/cgroup/$NAME/tasks
 }
 
 case "$CMD" in
     start)
-       cd "$ATTIC" || exit 1
        [ -e "/run/netns/$NSNAME" ] || setup_network
        [ -d "$MOUNT" ] || create_subhost
-       grep -q "^$NAME $TARGET overlay" /proc/mounts || setup_rootfs
+       setup_rootfs
        START=/bin/bash
        [ -x $TARGET/startup ] && START=/startup
+       accounting
        exec ip netns exec $NSNAME unshare \
             --fork --pid --mount-proc --kill-child \
             --uts --ipc --mount --cgroup \
-            "--root=$TARGET" $START
+            chroot $TARGET $START
        ;;
     stop)
        umount $TARGET
        [ -e $IMAGE ] && umount $MOUNT
        ip netns del $NSNAME
+       rmdir /sys/fs/cgroup/$NAME
        ;;
     *)
        usage