Standalone make iso image, rather than build+run

Simpler to have an image that takes the kernel and initrd as input,
rather than building them into the image.

The rest need converting.

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

alpine/Dockerfile.bios

@@ -1,18 +0,0 @@
-# Create a legacy BIOS bootable ISO
-FROM mobylinux/alpine-bios:626757290dbb54109514af22108645cae9ea40c3
-
-WORKDIR /tmp/iso
-
-COPY initrd.img ./
-COPY kernel/x86_64/vmlinuz64 ./
-COPY isolinux.cfg ./isolinux/
-
-RUN cp /usr/share/syslinux/isolinux.bin ./isolinux/ && \
-    cp /usr/share/syslinux/ldlinux.c32 ./isolinux/
-
-RUN genisoimage -o ../mobylinux-bios.iso -l -J -R \
-                -c isolinux/boot.cat  \
-                -b isolinux/isolinux.bin \
-                   -no-emul-boot -boot-load-size 4 -boot-info-table \
-                -V MobyLinux . && \
-    isohybrid ../mobylinux-bios.iso

alpine/Makefile

@@ -39,9 +39,9 @@ mobylinux-efi.iso: Dockerfile.efi initrd.img kernel/x86_64/vmlinuz64
 	docker run --net=none --log-driver=none --rm --cap-add sys_admin moby-efi:build cat /tmp/efi/mobylinux.efi > mobylinux.efi
 	docker run --net=none --log-driver=none --rm --cap-add sys_admin moby-efi:build cat /tmp/efi/mobylinux-efi.iso > $@
 
-mobylinux-bios.iso: Dockerfile.bios initrd.img kernel/x86_64/vmlinuz64 isolinux.cfg
-	tar cf - $^ | docker build -t moby-bios:build -f Dockerfile.bios -
-	docker run --net=none --log-driver=none --rm moby-bios:build cat /tmp/mobylinux-bios.iso > $@
+mobylinux-bios.iso: initrd.img kernel/x86_64/vmlinuz64
+	tar cf - initrd.img -C kernel/x86_64 vmlinuz64 | \
+	  docker run --net=none --log-driver=none --rm -i mobylinux/alpine-bios:67236852ecf950af0486ac22b0963b404d16c348 >$@
 
 common: initrd.img
 	$(MAKE) -C kernel

alpine/base/alpine-bios/Dockerfile

@@ -2,7 +2,15 @@ FROM alpine:3.4
 
 RUN \
   apk update && apk upgrade && \
-  apk add \
+  apk add --no-cache \
   cdrkit \
   syslinux \
-  && rm -rf /var/cache/apk/*
+  && true
+
+WORKDIR /tmp/iso
+
+COPY isolinux.cfg ./isolinux/
+
+COPY make-iso /usr/bin
+
+CMD [ "/usr/bin/make-iso" ]

alpine/base/alpine-bios/Makefile

@@ -7,7 +7,7 @@ default: push
 
 hash:
 	docker pull $(BASE)
-	tar cf - Dockerfile | docker build --no-cache -t $(IMAGE):build -
+	tar cf - Dockerfile make-iso isolinux.cfg | docker build --no-cache -t $(IMAGE):build -
 	docker run --rm $(IMAGE):build sha1sum /lib/apk/db/installed | sed 's/ .*//' > hash
 
 push: hash

alpine/base/alpine-bios/make-iso

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+# input is a tarball of vmlinuz64 and initrd.img on stdin
+# output is an iso on stdout
+
+cp /usr/share/syslinux/isolinux.bin ./isolinux/
+cp /usr/share/syslinux/ldlinux.c32 ./isolinux/
+
+tar xf -
+
+genisoimage -o ../mobylinux-bios.iso -l -J -R \
+                -c isolinux/boot.cat  \
+                -b isolinux/isolinux.bin \
+                   -no-emul-boot -boot-load-size 4 -boot-info-table \
+                -V MobyLinux .
+
+isohybrid ../mobylinux-bios.iso
+
+cat ../mobylinux-bios.iso