Switch to GPT partition format.

src/platform/installer/chromeos_install_functions.sh

+#!/bin/sh
+
+# 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.
+
+# Shell functions to help create a bootable image or install to a hard disk.
+# NOTE: Please keep this file dash and busybox compliant.
+
+# Variables that affect the install process. Set these as desired before
+# sourcing this file.
+MBR=${MBR:-/tmp/gpt.mbr}
+GPT=${GPT:-gpt}
+STATEFUL_PART_SIZE=${STATEFUL_PART_SIZE:-}  # Defaults to automatic computation.
+SWAP_PART_SIZE=${SWAP_PART_SIZE:-$((1024 * 1024 * 1024))}
+DEFAULT_STATEFUL_PART_SIZE=${DEFAULT_STATEFUL_PART_SIZE:-$((512 * 1024 * 1024))}
+
+# Given a path, return the size of the file or device at that path. This
+# fills in the GET_SIZE_RESULT variable.
+GET_SIZE_RESULT=
+get_size() {
+  local path="$1"
+
+  GET_SIZE_RESULT=0
+  if [ -b "$path" ] ; then
+    local device="${path#/dev/}"
+    if [ -f "/sys/block/${device}/size" ] ; then
+      # device must be like 'sdb'
+      GET_SIZE_RESULT=$(cat "/sys/block/${device}/size")
+    else
+      # device must be like 'sdb3'
+      local part="$device"
+      local len=${#part}
+      device=$(printf "%0.$((len - 1))s" $part)
+      GET_SIZE_RESULT=$(cat "/sys/block/${device}/${part}/size")
+    fi
+    GET_SIZE_RESULT=$((GET_SIZE_RESULT * 512))
+  else
+    GET_SIZE_RESULT=$(stat -c%s "$path")  # Bytes
+  fi
+}
+
+# A dd equivalent that tries to use a large block size.
+do_copy() {
+  local in="$1"      # Input file
+  local out="$2"     # Output file
+  local seek_offset="$3"  # Offset where to write the data, in bytes.
+  local skip_offset="$4"  # Offset from where to read the data, in bytes.
+
+  # We use a 4M output block size
+  local bs=$((4 * 1024 * 1024))
+
+  local skip_count=$((skip_offset / 512))
+
+  # How much initial non-aligned data do we need to copy?
+  local begin_size=$((bs - (seek_offset % bs)))
+  local count=$((begin_size / 512))
+  local seek=$((seek_offset / 512))
+  sudo dd if="$in" of="$out" bs=512 \
+    skip=$skip_count seek=$seek count=$count conv=notrunc
+
+  # Now copy the rest of the data with output aligned at $bs
+  seek=$(( (seek_offset + begin_size) / bs ))
+  sudo dd if="$in" of="$out" ibs=512 obs=$bs \
+    skip=$((skip_count + count)) seek=$seek conv=notrunc
+}
+
+# Computes the required install size for the system. This does not include
+# the stateful partition. The call fills in the SYSTEM_INSTALL_SIZE variable.
+SYSTEM_INSTALL_SIZE=
+get_system_install_size() {
+  local rootfs=$1
+  local type=$2  # Either 'minimal' or 'full'
+
+  # Approx space for GPT metadata
+  local gpt_size=$((34 * 1024))
+
+  # Determine the size of one rootfs partition.
+  get_size "$rootfs"
+  local root_size=$GET_SIZE_RESULT
+
+  # A minimal install has just the stateful and system partitions.
+  SYSTEM_INSTALL_SIZE=$((gpt_size + root_size))
+  if [ "$type" = "full" ] ; then
+    # A full install also includes a secondary system partition and swap.
+    SYSTEM_INSTALL_SIZE=$((SYSTEM_INSTALL_SIZE + root_size))
+    SYSTEM_INSTALL_SIZE=$((SYSTEM_INSTALL_SIZE + SWAP_PART_SIZE))
+  fi
+}
+
+# Computes the size of the stateful partition. If the STATEFUL_PART_SIZE is
+# already set then we'll use that, otherwise it will default to the free
+# space on a block device or a default value if output is to a file.
+get_stateful_part_size() {
+  local rootfs=$1
+  local dest=$2
+  local type=$3
+
+  if [ -n "$STATEFUL_PART_SIZE" ] ; then
+    return;  # Already computed or they set an override value.
+  fi
+  if [ -b "$dest" ] ; then
+    # For a block device, we'll default to using up all free space.
+    get_system_install_size "$rootfs" "$type"
+    get_size "$dest"
+    STATEFUL_PART_SIZE=$((GET_SIZE_RESULT - SYSTEM_INSTALL_SIZE))
+  else
+     # We'll use a default stateful part size.
+    STATEFUL_PART_SIZE=$((DEFAULT_STATEFUL_PART_SIZE))
+  fi
+}
+
+# Verifies that it is really OK to install to the destination.
+do_verify() {
+  local rootfs=$1  # Path to file/device containing the system rootfs
+  local dest=$2    # Path to file/device on which the install will happen
+  local type=$3    # Either 'minimal' or 'full'
+
+  if [ -e "$dest" ] ; then
+    echo "This will erase all data at this destination: $dest"
+    read -p "Are you sure (y/N)? " SURE
+    if [ "$SURE" != "y" ] ; then
+      echo "Ok, better safe than sorry; you answered '$SURE'."
+      exit 1
+    fi
+
+    if [ -b "$dest" ] ; then
+      # Do we have enough room to install on the block device?
+      get_system_install_size "$rootfs" "$type"
+      get_stateful_part_size "$rootfs" "$dest" "$type"
+      local size_needed=$((SYSTEM_INSTALL_SIZE + STATEFUL_PART_SIZE))
+
+      get_size "$dest"
+      local dest_size=$GET_SIZE_RESULT
+      if [ $dest_size -lt $size_needed ] ; then
+        echo "Error: Destination device '$dest' is too small:"
+        echo "  ($dest_size vs $size_needed)"
+        exit 1
+      fi
+    fi
+  fi
+}
+
+do_cleanup() {
+  sudo losetup -d "$LOOP_DEV"
+}
+
+# Given a rootfs, sets up the destination to boot it with proper partitions.
+install_chromeos() {
+  local rootfs=$1  # Path to file/device containing the system rootfs
+  local dest=$2    # Path to file/device on which to create a bootable install
+  local label_prefix=$3  # Prefix character to use for file system labels
+  local type=$4    # Either 'minimal' or 'full'
+
+  # How big are each of our partitions?
+  get_size "$rootfs"
+  local system_part_size=$GET_SIZE_RESULT  # bytes
+  get_stateful_part_size "$rootfs" "$dest" "$type"
+  local stateful_part_size=$STATEFUL_PART_SIZE
+  local swap_part_size=$SWAP_PART_SIZE
+
+  # If we output to a file, then create/truncate it to the proper length.
+  if [ ! -b "$dest" ] ; then
+    get_system_install_size "$rootfs" "$type"
+    local dest_size=$((SYSTEM_INSTALL_SIZE + stateful_part_size))
+    dd if=/dev/zero of="$dest" bs=1 count=1 seek=$((dest_size - 1))
+  fi
+
+  # -- Partitions --
+
+  # What partition should we make bootable by default?
+  local boot_part=
+
+  # Set up GPT partition format
+  sudo dd if=/dev/zero of="$dest" bs=1M count=1 conv=notrunc
+  sudo $GPT create -f "$dest"
+
+  # Add and label all partitions. The current partitioning scheme(s) are very
+  # likely to change. NOTE: The label is not the same as the file system label.
+  if [ "$type" = "minimal" ] ; then
+    #  Part    Label          FS           Usage
+    #   1       User Data      (ext3/4)     Statefule partition
+    #   2       System         (ext3/4)     Root file system
+    sudo $GPT add -i 1 -s $((stateful_part_size / 512)) -t linux "$dest"
+    sudo $GPT add -i 2 -s $((system_part_size / 512))   -t linux "$dest"
+
+    sudo $GPT label -i 1 -l "User Data" "$dest"
+    sudo $GPT label -i 2 -l "System" "$dest"
+
+    boot_part=2
+  else
+    #  Part    Label          FS           Usage
+    #   1       User Data      (ext3/4)     Statefule partition
+    #   2       Swap           swap         May be used for swap
+    #   3       System         (ext3/4)     Root file system
+    #   4       System2        (ext3/4)     Root file system (alternate)
+    sudo $GPT add -i 1 -s $((stateful_part_size / 512)) -t linux "$dest"
+    sudo $GPT add -i 2 -s $((swap_size / 512))          -t linux-swap "$dest"
+    sudo $GPT add -i 3 -s $((system_part_size / 512))   -t linux "$dest"
+    sudo $GPT add -i 4 -s $((system_part_size / 512))   -t linux "$dest"
+
+    sudo $GPT label -i 1 -l "User Data" "$dest"
+    sudo $GPT label -i 2 -l "Swap"      "$dest"
+    sudo $GPT label -i 3 -l "System"    "$dest"
+    sudo $GPT label -i 4 -l "System2"   "$dest"
+
+    boot_part=3
+  fi
+
+  # Set up a boot MBR for booting on legacy devices.
+  sudo $GPT boot -b "$MBR" -i $boot_part "$dest"
+
+  # -- System Image --
+
+  # We copy the system image a bit strangely here because we have observed
+  # cases in install to hard disk where people ctrl-c the operation and then
+  # are not longer able to properly boot a USB image. This is because when
+  # booting from USB we set the root device by LABEL, so if you partially
+  # copy the FS here without updating the label then a subsequent USB boot
+  # may try to use the wrong device and fail.
+
+  echo "Copying the system image. This might take a while..."
+  local offset_sectors=$(sudo $GPT -r show -l "$dest" | grep "\"System\"" \
+    | awk '{ print $1 }')
+
+  # Copy first 2 kibibytes of the root image to a temp file, set the label,
+  # and then copy it to the dest.
+  # NOTE: This hack won't work if we stop using an ext based FS
+  local superblock_offset=1024
+  local label_field_offset=120
+  local label_field_length=16
+  local tmp=$(mktemp)
+  sudo dd if="$rootfs" of="$tmp" bs=1024 count=2
+  sudo dd if=/dev/zero of="$tmp" bs=1                \
+    seek=$((superblock_offset + label_field_offset)) \
+    count=$label_field_length conv=notrunc
+  echo -n "${label_prefix}-ROOT" | sudo dd of="$tmp" \
+    seek=$((superblock_offset + label_field_offset)) \
+    bs=1 count=$((label_field_length - 1)) conv=notrunc
+  sudo dd if="$tmp" of="$dest" bs=512 seek=$offset_sectors conv=notrunc
+  rm "$tmp"
+
+  # Copy all but the first 2 kibibytes to the destination now.
+  do_copy "$rootfs" "$dest" $(( (offset_sectors * 512) + 2048)) 2048
+
+  # -- Stateful Partition --
+
+  echo "Formatting the user data partition..."
+  offset=$(sudo $GPT -r show -l "$dest" | grep "\"User Data\"" \
+    | awk '{ print $1 }')
+  LOOP_DEV=$(sudo losetup -f)
+  if [ -z "$LOOP_DEV" ]
+  then
+    echo "No free loop device. Free up a loop device or reboot. exiting."
+    exit 1
+  fi
+
+  trap do_cleanup EXIT
+
+  echo "Creating stateful partition..."
+  sudo losetup -o $((offset * 512)) "$LOOP_DEV" "$dest"
+  sudo mkfs.ext3 -F -b 4096 -L "${label_prefix}-STATE" \
+    "$LOOP_DEV" $((stateful_part_size / 4096))
+  sync
+  sudo losetup -d "$LOOP_DEV"
+  sync
+
+  trap - EXIT
+}