Un-hardcode host/guest IP

I was running into trouble using gitian LXC INSIDE a VirtualBox VM, because
the 10.0.2.x IP range overlaps with the range that VirtualBox uses for
its internal NAT network.

This commit makes it possible to override the host and guest IP that
is used during LXC image creation and the build, using environment variables:

- `GITIAN_HOST_IP` (default=10.0.2.2, host IP from the viewpoint of the
   VM, can be used for both LXC and KVM)
- `LXC_GUEST_IP` (default=10.0.2.5, guest IP from the viewpoint of the
   host, effective for LXC only)

When these are not defined the behavior remains the same as before.

bin/make-base-vm

@@ -20,10 +20,10 @@ usage() {
   --vbox     use VirtualBox instead of kvm
 
   The MIRROR_HOST environment variable can be used to change the
-  apt-cacher host.  It should be something that the target VM can
-  resolve.  It may be set to 127.0.0.1, in which case it will be
-  changed to 10.0.2.2 on the guest.  10.0.2.2 is the host IP as visible
-  from the guest under qemu networking.
+  apt-cacher host.  It should be something that both the host and the
+  target VM can reach.  It may be set to 127.0.0.1, in which case it will be
+  changed to 10.0.2.2 on the guest (or GITIAN_HOST_IP if it is defined)
+  10.0.2.2 is the host IP as visible from the guest under qemu networking.
 EOF
 }
 
@@ -104,6 +104,7 @@ if [ -e $OUT.qcow2 ]; then
   exit 1
 fi
 
+libexec/config-bootstrap-fixup
 rm -rf $OUT
 sudo vmbuilder kvm ubuntu --rootsize 10240 --arch=$ARCH --suite=$SUITE --addpkg=$addpkg --removepkg=$removepkg --ssh-key=var/id_dsa.pub --ssh-user-key=var/id_dsa.pub --mirror=$MIRROR --security-mirror=$SECURITY_MIRROR --dest=$OUT --flavour=$FLAVOUR --firstboot=`pwd`/target-bin/bootstrap-fixup
 mv $OUT/*.qcow2 $OUT.qcow2

etc/lxc.config.in

@@ -26,7 +26,9 @@ lxc.mount.entry=sysfs ROOTFS/sys sysfs defaults  0 0
 # Container with network virtualized using a pre-configured bridge named br0 and
 # veth pair virtual network devices
 # On the host, run: ifconfig br0 up 10.0.2.2
+# Alternatively, you can use another IP range for the bridge interface, in this case set
+# the environment variables GITIAN_HOST_IP and LXC_GUEST_IP appropriately.
 lxc.network.type = veth
 lxc.network.flags = up
 lxc.network.link = br0
-lxc.network.ipv4 = 10.0.2.5/24
+lxc.network.ipv4 = GUESTIP/24

libexec/config-bootstrap-fixup

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+wd=`pwd`
+
+# Default host IP is 10.0.2.2
+if [ -z "$GITIAN_HOST_IP" ]; then
+  GITIAN_HOST_IP=10.0.2.2
+fi
+
+# Default to host IP if the MIRROR_HOST is not set, or set to 127.0.0.1
+if [ -z "$MIRROR_HOST" ] || [ "$MIRROR_HOST" == "127.0.0.1" ]; then
+  MIRROR_HOST=$GITIAN_HOST_IP
+fi
+
+sed "s;HOSTIP;$MIRROR_HOST;g" < target-bin/bootstrap-fixup.in > target-bin/bootstrap-fixup

libexec/config-lxc

@@ -1,4 +1,9 @@
 #!/bin/bash
 
 wd=`pwd`
-sed "s;ROOTFS;$wd/target-$LXC_SUITE-$LXC_ARCH;;s;ARCH;$LXC_ARCH;g" < etc/lxc.config.in > var/lxc.config
+
+if [ -z "$LXC_GUEST_IP" ]; then
+    LXC_GUEST_IP=10.0.2.5
+fi
+
+sed "s;ROOTFS;$wd/target-$LXC_SUITE-$LXC_ARCH;;s;ARCH;$LXC_ARCH;g;;s;GUESTIP;$LXC_GUEST_IP;g" < etc/lxc.config.in > var/lxc.config

libexec/make-clean-vm

@@ -60,6 +60,7 @@ case $VMSW in
     ;;
   LXC)
     cp -a $BASE $OUT
+    libexec/config-bootstrap-fixup
     on-target -u root bash < target-bin/bootstrap-fixup
     ;;
   VBOX)

target-bin/bootstrap-fixup

@@ -1,8 +0,0 @@
-#!/bin/sh
-
-set -e
-
-. /etc/lsb-release
-
-echo "deb http://10.0.2.2:3142/archive.ubuntu.com/ubuntu $DISTRIB_CODENAME main universe" > $1/etc/apt/sources.list
-echo "deb http://10.0.2.2:3142/archive.ubuntu.com/ubuntu $DISTRIB_CODENAME-updates main universe" >> $1/etc/apt/sources.list

target-bin/bootstrap-fixup.in

@@ -0,0 +1,8 @@
+#!/bin/sh
+
+set -e
+
+. /etc/lsb-release
+
+echo "deb http://HOSTIP:3142/archive.ubuntu.com/ubuntu $DISTRIB_CODENAME main universe" > $1/etc/apt/sources.list
+echo "deb http://HOSTIP:3142/archive.ubuntu.com/ubuntu $DISTRIB_CODENAME-updates main universe" >> $1/etc/apt/sources.list