Fix architecture handling in hooks. We know we're always being invoked

from a launchpad-buildd-like setup, which passes ARCH and SUBARCH in the
environment, because auto/config and auto/build both rely on this.  So
don't scatter dpkg --print-architecture calls throughout, especially
when many of these are not cross-build-aware.

debian/changelog

@@ -13,6 +13,11 @@ livecd-rootfs (2.376) UNRELEASED; urgency=medium
     actually warranted in the normal case.
   * If a subarch is specified for a cloud image build, don't build rootfs
     artifacts; these should come from the 'generic' build.
+  * Fix architecture handling in hooks.  We know we're always being invoked
+    from a launchpad-buildd-like setup, which passes ARCH and SUBARCH in the
+    environment, because auto/config and auto/build both rely on this.  So
+    don't scatter dpkg --print-architecture calls throughout, especially
+    when many of these are not cross-build-aware.
 
  -- Łukasz 'sil2100' Zemczak <lukasz.zemczak@ubuntu.com>  Thu, 04 Feb 2016 17:31:18 +0100
 

live-build/ubuntu-core/hooks/01-divert-grub-install.chroot_early

@@ -1,7 +1,5 @@
 #!/bin/sh -ex
 
-ARCH=$(dpkg --print-architecture)
-
 case $ARCH in
     i386|amd64)
         dpkg-divert --quiet --add \

live-build/ubuntu-core/hooks/12-add-foreign-libc6.chroot

@@ -4,7 +4,7 @@ set -ex
 
 echo "I: Checking if we are amd64 and libc6:i386 should be installed"
 
-if [ "$(dpkg --print-architecture)" = "amd64" ]; then
+if [ "$ARCH" = "amd64" ]; then
     echo "I: Enabling i386 multiarch support on amd64"
     dpkg --add-architecture i386
 

live-build/ubuntu-core/hooks/16-ensure-uboot.chroot

@@ -2,7 +2,7 @@
 
 set -e
 
-case "$(dpkg --print-architecture)" in
+case $ARCH in
     arm*)
         mkdir -p /boot/uboot
         cat > /etc/fw_env.config <<EOF

live-build/ubuntu-core/hooks/99-undivert-grub-install.chroot

@@ -1,7 +1,5 @@
 #! /bin/sh -ex
 
-ARCH=$(dpkg --print-architecture)
-
 case $ARCH in
     i386|amd64)
         rm -f /usr/sbin/grub-install

live-build/ubuntu-cpc/hooks/001-divert-sync.chroot_early

@@ -1,8 +1,6 @@
 #!/bin/sh
 set -e
 
-ARCH=$(dpkg --print-architecture)
-
 dpkg-divert --quiet --add --divert /bin/sync.REAL --rename /bin/sync
 cat > /bin/sync <<'EOF'
 #! /bin/sh

live-build/ubuntu-cpc/hooks/032-disk-image.binary

@@ -1,9 +1,10 @@
 #!/bin/bash -eux
-architecture=$(chroot chroot dpkg --print-architecture)
-if [ "$architecture" = "ppc64el" ]; then
-    echo "ppc64el disk images are handled separately"
-    exit 0
-fi
+case $ARCH in
+	ppc64el)
+		echo "ppc64el disk images are handled separately"
+		exit 0
+		;;
+esac
 
 . /build/config/functions
 

live-build/ubuntu-cpc/hooks/033-disk-image-uefi.binary

@@ -1,11 +1,10 @@
 #!/bin/bash -eux
 
-architecture=$(chroot chroot dpkg --print-architecture)
-case $architecture in
+case $ARCH in
     amd64|arm64)
         ;;
     *)
-        echo "We don't create EFI images for $architecture."
+        echo "We don't create EFI images for $ARCH."
         exit 0
         ;;
 esac
@@ -17,7 +16,7 @@ apt-get -qqy install dosfstools gdisk
 create_partitions() {
     disk_image="$1"
     sgdisk "${disk_image}" --zap-all
-    case $architecture in
+    case $ARCH in
         arm64)
             sgdisk "${disk_image}" \
                 --new=15:0:204800 \
@@ -62,7 +61,7 @@ install_grub() {
     efi_boot_dir="/boot/efi/EFI/BOOT"
     chroot mountpoint mkdir -p "${efi_boot_dir}"
 
-    case $architecture in
+    case $ARCH in
         arm64)
             chroot mountpoint apt-get -qqy install --no-install-recommends grub-efi-arm64 grub-efi-arm64-bin
             grub_modules="part_gpt fat gzio ext2 normal chain boot configfile linux search_fs_uuid search_label terminal serial video video_fb efi_gop"
@@ -101,7 +100,7 @@ EOF
         chroot mountpoint cp /boot/efi/EFI/BOOT/grub.cfg /boot/efi/boot/grub
     fi
 
-    if [ $architecture = "amd64" ]; then
+    if [ "$ARCH" = "amd64" ]; then
         # Install the BIOS/GPT bits. Since GPT boots from the ESP partition,
         # it means that we just run this simple command and we're done
         chroot mountpoint grub-install --target=i386-pc "${loop_device}"

live-build/ubuntu-cpc/hooks/034-disk-image-ppc64el.binary

@@ -1,6 +1,5 @@
 #!/bin/bash -eux
-architecture=$(chroot chroot dpkg --print-architecture)
-if [ "$architecture" != "ppc64el" ]; then
+if [ "$ARCH" != "ppc64el" ]; then
     exit 0
 fi
 

live-build/ubuntu-cpc/hooks/040-vmdk-image.binary

@@ -3,13 +3,11 @@
 #
 # Generate VMDK files
 
-architecture=$(chroot chroot dpkg --print-architecture)
-
 extension="disk1.vmdk"
 
-case ${architecture} in
+case $ARCH in
          i386|amd64) ;;
-                  *) echo "VMDK images are not supported for ${architecture} yet.";
+                  *) echo "VMDK images are not supported for $ARCH yet.";
                      exit 0;;
 esac
 

live-build/ubuntu-cpc/hooks/041-vmdk-ova-image.binary

@@ -9,18 +9,16 @@
 #
 # For this step, we re-use the VMDK's made in 040-vmdk-image.binary
 
-architecture=$(chroot chroot dpkg --print-architecture)
-
-case ${architecture} in
+case $ARCH in
         amd64|i386) ;;
-                 *) echo "OVA images are not supported for ${architecture} yet.";
+                 *) echo "OVA images are not supported for $ARCH yet.";
                      exit 0;;
 esac
 cur_d=${PWD}
 my_d=$(dirname $(readlink -f ${0}))
 
 base_vmdk="livecd.ubuntu-cpc.disk1.vmdk"
-if [ $architecture = "amd64" ]; then
+if [ "$ARCH" = "amd64" ]; then
     base_vmdk="livecd.ubuntu-cpc.uefi.vmdk"
 fi
 

live-build/ubuntu-cpc/hooks/042-vagrant.binary

@@ -15,13 +15,16 @@
 cur_d=${PWD}
 my_d=$(dirname $(readlink -f ${0}))
 
-architecture=$(chroot chroot dpkg --print-architecture)
 base_vmdk="livecd.ubuntu-cpc.disk1.vmdk"
 
-if [[ ! "${architecture}" =~ (amd64|i386) ]]; then
-	echo "Vagrant images are not supported for ${architecture}"
-	exit 0
-elif [ ! -e ${base_vmdk} ]; then
+case $ARCH in
+	amd64|i386) ;;
+	*)
+		echo "Vagrant images are not supported for $ARCH"
+		exit 0
+esac
+
+if [ ! -e ${base_vmdk} ]; then
 	echo "Did not find VMDK to produce Vagrant images."
     exit 0
 fi

live-build/ubuntu-cpc/hooks/999-cpc-fixes.chroot

@@ -18,8 +18,6 @@ _xchroot() {
 }
 
 #### COMMON architecture independent functions
-arch=$(_xchroot "${rootd}" dpkg --print-architecture)
-
 add_serial_console() {
    condev=$1
    idir="$rootd/etc/init"
@@ -127,7 +125,7 @@ fi
 #### END COMMON ARCH FUNCTIONS
 
 
-case $arch in
+case $ARCH in
 	# ARM images are special
 	armhf|arm64)
 		echo "Configuring ARM Serial Port"

live-build/ubuntu-desktop-next/hooks/500-move-kernel-to-device-tar.binary

@@ -8,7 +8,6 @@ echo "I: Moving kernel into device tarball"
 
 HERE="$(pwd)"
 TMPDIR="$(mktemp -d)"
-ARCH=$(dpkg --print-architecture)
 mkdir -p $TMPDIR/system/
 mkdir -p $TMPDIR/assets/
 

live-build/ubuntu-touch/hooks/60-install-click.chroot

@@ -20,12 +20,10 @@ tmpdir="$(mktemp -d)"
 cleanup () { rm -rf "$tmpdir"; }
 trap cleanup EXIT
 
-CLICKARCH=$(dpkg --print-architecture)
-
 wget --no-verbose -O "$tmpdir/click_list" "$click_list"
 for package in $(cat "$tmpdir/click_list")
 do
-    if echo $package | egrep -q "_$CLICKARCH.click|_all.click|_unknown.click|_multi.click"; then
+    if echo $package | egrep -q "_$ARCH.click|_all.click|_unknown.click|_multi.click"; then
         echo "Setting up $package"
         wget --no-verbose -O "$tmpdir/$package" "$click_uri/$package"
 	# FIXME: first attempt, a hard-coded list of the packages that go to