Prototype faster build (kind of ugly)

build_image

 #!/bin/bash
 
 # Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Script to build a bootable keyfob-based chromeos system image from within
 # a chromiumos setup. This assumes that all needed packages have been built into
 # the given target's root with binary packages turned on. This script will
 # build the Chrome OS image using only pre-built binary packages.
@@ skipping 51 matching lines @@
 if [ -z "$FLAGS_board" ] ; then
   error "--board is required."
   exit 1
 fi
 
 if [ "$FLAGS_rootfs_size" -gt "$FLAGS_rootfs_partition_size" ] ; then
   error "rootfs (${FLAGS_rootfs_size} MB) is bigger than partition (${FLAGS_rootfs_partition_size} MB)."
   exit 1
 fi
 
+EMERGE_CMD="emerge"
+EMERGE_BOARD_CMD="emerge-${FLAGS_board}"
+TOP_SCRIPTS_DIR="$(dirname $0)"
+if [ -e "${TOP_SCRIPTS_DIR}/.emerge" ]; then
+  echo "Using alternate emerge"
+  .  "${TOP_SCRIPTS_DIR}/.emerge"
+fi
+
 # Determine build version.
 . "${SCRIPTS_DIR}/chromeos_version.sh"
 
 # Use canonical path since some tools (e.g. mount) do not like symlinks.
 # Append build attempt to output directory.
 IMAGE_SUBDIR="${CHROMEOS_VERSION_STRING}-a${FLAGS_build_attempt}"
 OUTPUT_DIR="${FLAGS_output_root}/${FLAGS_board}/${IMAGE_SUBDIR}"
 ROOT_FS_DIR="${OUTPUT_DIR}/rootfs"
 ROOT_FS_IMG="${OUTPUT_DIR}/rootfs.image"
 
@@ skipping 144 matching lines @@
   $SCRIPTS_DIR/mount_gpt_image.sh --from "$OUTPUT_DIR" \
     --image "$image_to_mount" -r "$root_fs_dir" -s "$stateful_dir"
 
   if [ "$image_type" == "dev" ]; then
     # Determine the root dir for developer packages.
     local root_dev_dir="$root_fs_dir"
     [ $FLAGS_statefuldev -eq $FLAGS_TRUE ] && \
       root_dev_dir="$root_fs_dir/usr/local"
 
     # Install developer packages described in chromeos-dev.
-    sudo INSTALL_MASK="$INSTALL_MASK" emerge-${BOARD} \
+    sudo INSTALL_MASK="$INSTALL_MASK" ${EMERGE_BOARD_CMD} \
         --root="$root_dev_dir" --root-deps=rdeps \
         --usepkgonly chromeos-dev $EMERGE_JOBS
   elif [ "$image_type" == "recovery" ]; then
     # Install recovery installer
-    sudo emerge-${BOARD} --root=$root_fs_dir --usepkgonly \
+    sudo ${EMERGE_BOARD_CMD} --root=$root_fs_dir --usepkgonly \
         --root-deps=rdeps --nodeps chromeos-recovery
   fi
 
   # Re-run ldconfig to fix /etc/ldconfig.so.cache.
   sudo /sbin/ldconfig -r "$root_fs_dir"
 
   # Mark the image as a developer image (input to chromeos_startup).
   sudo mkdir -p "$root_fs_dir/root"
   sudo touch "$root_fs_dir/root/$file_to_touch"
 
@@ skipping 147 matching lines @@
 setup_symlinks_on_root "${DEV_IMAGE_ROOT}" "${STATEFUL_DIR}/var" \
   "${STATEFUL_DIR}"
 
 # Perform binding rather than symlinking because directories must exist
 # on rootfs so that we can bind at run-time since rootfs is read-only
 echo "Binding directories from stateful partition onto the rootfs"
 sudo mkdir -p "${ROOT_FS_DIR}/usr/local"
 sudo mount --bind "${DEV_IMAGE_ROOT}" "${ROOT_FS_DIR}/usr/local"
 sudo mkdir -p "${ROOT_FS_DIR}/var"
 sudo mount --bind "${STATEFUL_DIR}/var" "${ROOT_FS_DIR}/var"
+sudo mkdir -p "${ROOT_FS_DIR}/dev"
 
 # We "emerge --root=$ROOT_FS_DIR --root-deps=rdeps --usepkgonly" all of the
 # runtime packages for chrome os. This builds up a chrome os image from binary
 # packages with runtime dependencies only.  We use INSTALL_MASK to trim the
 # image size as much as possible.
-sudo INSTALL_MASK="$INSTALL_MASK" emerge-${BOARD} \
+sudo INSTALL_MASK="$INSTALL_MASK" ${EMERGE_BOARD_CMD} \
   --root="$ROOT_FS_DIR" --root-deps=rdeps \
   --usepkgonly chromeos $EMERGE_JOBS
 
 # Create EFI System Partition to boot stock EFI BIOS (but not ChromeOS EFI
 # BIOS). We only need this for x86, but it's simpler and safer to keep the disk
 # images the same for both x86 and ARM.
 ESP_IMG=${OUTPUT_DIR}/esp.image
 # NOTE: The size argument for mkfs.vfat is in 1024-byte blocks. We'll hard-code
 # it to 16M for now.
 ESP_BLOCKS=16384
@@ skipping 135 matching lines @@
 set +x
 
 echo "Done.  Image created in ${OUTPUT_DIR}"
 echo "Chromium OS image created as $PRISTINE_IMAGE_NAME"
 if [ "$FLAGS_recovery" -eq "$FLAGS_TRUE" ]; then
   echo "Recovery image created as $PRISTINE_IMAGE_NAME"
 fi
 if [ "$FLAGS_withdev" -eq "$FLAGS_TRUE" ]; then
   echo "Developer image created as $DEVELOPER_IMAGE_NAME"
 fi
+
 echo "To copy to USB keyfob, OUTSIDE the chroot, do something like:"
 echo "  ./image_to_usb.sh --from=${OUTSIDE_OUTPUT_DIR} --to=/dev/sdX"
 echo "To convert to VMWare image, OUTSIDE the chroot, do something like:"
 echo "  ./image_to_vmware.sh --from=${OUTSIDE_OUTPUT_DIR}"
 echo "from the scripts directory where you entered the chroot."