#!/bin/sh

# Copyright (c) 2012 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.

. /usr/share/misc/chromeos-common.sh

UNDO_MOUNTS=
cleanup_mounts()
{
  # On failure unmount all saved mount points and repair stateful
  for mount_point in ${UNDO_MOUNTS}; do
    umount -n ${mount_point}
  done
  # Leave /mnt/stateful_partition mounted for clobber-state to handle.
  chromeos-boot-alert self_repair
  clobber-log -- \
    "Self-repair incoherent stateful partition: $*. History: ${UNDO_MOUNTS}"
  exec clobber-state "fast keepimg"
}
remember_mount()
{
    UNDO_MOUNTS="$1 ${UNDO_MOUNTS}"
}
mount_or_fail()
{
  local mount_point
  # -c: Never canonicalize: it is a hazard to resolve symlinks.
  # -n: Do not write to mtab: we don't use it.
  if mount -c -n "$@" ; then
    # Last parameter contains the mount point
    shift $(( $# - 1 ))
    # Push it on the undo stack if we fail later
    remember_mount "$1"
    return
  fi
  cleanup_mounts "failed to mount $*"
}
# Assert that the argument is a directory.
# On failure, clobbers the stateful partition.
check_directory()
{
  local path="$1"
  if [ -L "${d}" ] || [ ! -d "${path}" ]; then
    cleanup_mounts "${d} is not a directory"
  fi
}

# Checks if /var is close to being full.
# Returns exit code of 0 (boolean true) if there is less than 10MB of
# free space left in /var.
is_var_full() {
  local var_avail="$(df -k --output=avail /var | grep -E -o '[0-9]+')"
  [ ${var_avail} -lt 10000 ]
}

# Sanity check the date in case the RTC battery died and it initialized to
# something old (https://crbug.com/195715).  This doesn't need to be perfect,
# just somewhat recent/sane.  We'll recover later via tlsdate.
sanity_check_clock() {
  # We manage this base timestamp by hand.  It isolates us from bad clocks on
  # the system where this image was built/modified, and on the runtime image
  # (in case a dev modified random paths while the clock was out of sync).
  # Calculated using: date -d"01 Jan $(date +%Y) UTC" +%s
  local year="2017"
  local base_secs="1483228800"

  # See if the current time is older than our sanity time.  If so, pull up.
  if [ $(date -u +%s) -lt ${base_secs} ]; then
    date -u 01020000${year}
  fi
}

# Mount debugfs as bootstat depends on /sys/kernel/debug
mount -n -t debugfs -o nodev,noexec,nosuid,mode=0750,uid=0,gid=debugfs-access \
  debugfs /sys/kernel/debug

# bootstat writes timings to both tmpfs and debugfs.
bootstat pre-startup

# Some startup functions are split into a separate library which may be
# different for different targets (e.g., regular Chrome OS vs. embedded).
. /usr/share/cros/startup_utils.sh

mkdir -p /dev/pts /dev/shm
mount -n -t tmpfs -o nodev,noexec,nosuid shmfs /dev/shm
mount -n -t devpts -o noexec,nosuid,gid=5,mode=0620 devpts /dev/pts

# Initialize kernel sysctl settings early so that they take effect for boot
# processes.
sysctl -q --system

# CROS_DEBUG equals one if we've booted in developer mode or we've
# booted a developer image.
crossystem "cros_debug?1"
CROS_DEBUG=$((! $?))

# Developer mode functions (defined in dev_utils.sh and will be loaded
# only when CROS_DEBUG=1).
dev_check_block_dev_mode() { true; }
dev_update_stateful_partition() { true; }
dev_gather_logs() { true; }
dev_mount_packages() { true; }
dev_is_debug_build() { false; }

# do_* are wrapper functions that may be redefined in developer mode or test
# images. Find more implementation in {dev,test,factory}_utils.sh.
do_mount_var_and_home_chronos() { mount_var_and_home_chronos; }

if [ "${CROS_DEBUG}" -eq 1 ]; then
  . /usr/share/cros/dev_utils.sh
fi

# Prepare to mount stateful partition
ROOT_DEV=$(rootdev -s)
ROOTDEV_RET_CODE=$?
# Example root dev types we need to handle: /dev/sda2 -> /dev/sda,
# /dev/mmcblk0p0 -> /dev/mmcblk0p, /dev/ubi2_1 -> /dev/ubi
ROOTDEV_TYPE=$(echo $ROOT_DEV | sed 's/[0-9_]*$//')
ROOTDEV_NAME=${ROOTDEV_TYPE##/dev/}
ROOTDEV_REMOVABLE=$(cat "/sys/block/${ROOTDEV_NAME}/removable")

# Load the GPT helper functions and the image settings.
. "/usr/sbin/write_gpt.sh"
if [ "${ROOTDEV_REMOVABLE}" = "1" ]; then
  load_partition_vars
else
  load_base_vars
fi

# Check if we are booted on physical media. rootdev will fail if we are in
# an initramfs or tmpfs rootfs (ex, factory installer images. Note recovery
# image also uses initramfs but it never reach here). When using initrd+tftpboot
# (some old netboot factory installer), ROOTDEV_TYPE will be /dev/ram.
STATE_DEV=""
if [ "$ROOTDEV_RET_CODE" = "0" -a "$ROOTDEV_TYPE" != "/dev/ram" ]; then
  # Find our stateful partition mount point.
  # To support multiple volumes on a single UBI device, if the stateful
  # partition is not found on ubi${PARTITION_NUM_STATE}_0, check
  # ubi0_${PARTITION_NUM_STATE}.
  STATE_FLAGS="nodev,noexec,nosuid,noatime"
  if [ "${FORMAT_STATE}" = "ubi" ]; then
    STATE_DEV="/dev/ubi${PARTITION_NUM_STATE}_0"
    if [ ! -e "${STATE_DEV}" ]; then
      STATE_DEV="/dev/ubi0_${PARTITION_NUM_STATE}"
    fi
  else
    DIRTY_EXPIRE_CENTISECS=$(sysctl -n vm.dirty_expire_centisecs)
    COMMIT_INTERVAL=$(( DIRTY_EXPIRE_CENTISECS / 100 ))
    STATE_DEV=${ROOTDEV_TYPE}${PARTITION_NUM_STATE}
    STATE_FLAGS="${STATE_FLAGS},commit=${COMMIT_INTERVAL}"
  fi

  # Check if we enable ext4 crypto.
  if [ "${FS_FORMAT_STATE}" = "ext4" ]; then
    # Enable directory encryption for existing install.
    if ! dumpe2fs -h "${STATE_DEV}" 2>/dev/null | \
         grep -qe "^Filesystem features:.* encrypt.*"; then
      # The stateful partition is not set for encryption.
      # Check if we should migrate.
      if ext4_dir_encryption_supported; then
        # Ensure to replay the journal first so it doesn't overwrite the flag.
        e2fsck -p -E journal_only "${STATE_DEV}" || :
        # The kernel support encryption, do it!
        tune2fs -O encrypt "${STATE_DEV}" || :
      fi
    fi
  fi

  # Mount stateful partition from STATE_DEV.
  if ! mount -n -t ${FS_FORMAT_STATE} -o ${STATE_FLAGS} \
         "${STATE_DEV}" /mnt/stateful_partition; then
    # Try to rebuild the stateful partition by clobber-state. (Not using fast
    # mode out of security consideration: the device might have gotten into this
    # state through power loss during dev mode transition).
    chromeos-boot-alert self_repair
    clobber-log --repair "${STATE_DEV}" \
        "Self-repair corrupted stateful partition"
    exec clobber-state "keepimg"
  fi

  # Mount the OEM partition.
  # mount_or_fail isn't used since this partition only has a filesystem
  # on some boards.
  OEM_FLAGS="ro,nodev,noexec,nosuid"
  if [ "${FORMAT_OEM}" = "ubi" ]; then
    OEM_DEV="/dev/ubi${PARTITION_NUM_OEM}_0"
    if [ ! -e "${OEM_DEV}" ]; then
      OEM_DEV="/dev/ubi0_${PARTITION_NUM_OEM}"
    fi
  else
    OEM_DEV=${ROOTDEV_TYPE}${PARTITION_NUM_OEM}
  fi
  mount -n -t ${FS_FORMAT_OEM} -o ${OEM_FLAGS} ${OEM_DEV} /usr/share/oem
fi

# Make sure our clock is somewhat up-to-date.
# TODO: See if we can move this before the stateful initialization above.
sanity_check_clock

# This file is created by clobber-state after the transition
# to dev mode.
DEV_MODE_FILE="/mnt/stateful_partition/.developer_mode"

# Checks if developer mode is blocked.
dev_check_block_dev_mode "${DEV_MODE_FILE}"

# 'firmware-boot-update' is provided by chromeos-firmware for legacy systems.
# On most new boards, it should be simply an empty file.
firmware-boot-update

# File used to trigger a stateful reset.  Contains arguments for
# the "clobber-state" call.  This file may exist at boot time, as
# some use cases operate by creating this file with the necessary
# arguments and then rebooting.
RESET_FILE="/mnt/stateful_partition/factory_install_reset"

# Check for whether we need a stateful wipe, and alert the user as
# necessary.  We can wipe for several different reasons:
#  + User requested "power wash" which will create ${RESET_FILE}.
#  + Switch from verified mode to dev mode.  We do this if we're in
#    dev mode, and ${DEV_MODE_FILE} doesn't exist.  clobber-state
#    in this case will create the file, to prevent re-wipe.
#  + Switch from dev mode to verified mode.  We do this if we're in
#    verified mode, and ${DEV_MODE_FILE} still exists.  (This check
#    isn't necessarily reliable.)
#
# Stateful wipe for dev mode switching is skipped if the build is a debug build
# or if we've booted a non-recovery image in recovery mode (for example, doing
# Esc-F3-Power on a Chromebook with DEV-signed firmware); this protects various
# development use cases, most especially prototype units or booting Chromium OS
# on non-Chrome hardware. And because crossystem is slow on some platforms, we
# want to do the additional checks only after verified DEV_MODE_FILE existence.
if [ -O ${RESET_FILE} ]; then
  # Wipe requested on previous boot.
  chromeos-boot-alert power_wash
elif [ -z "${STATE_DEV}" ] || dev_is_debug_build; then
  # No physical stateful partition available, usually due to initramfs
  # (recovery image, factory install shim or netboot), or running from a
  # debug build image. Do not wipe.
  :
elif [ -O "${DEV_MODE_FILE}" ]; then
  if crossystem 'devsw_boot?0' && ! crossystem 'mainfw_type?recovery'; then
    # We're transitioning from dev mode to verified boot.
    # When coming back from developer mode, we don't need to
    # clobber as aggressively.  Fast will do the trick.
    chromeos-boot-alert leave_dev
    echo "fast keepimg" >"${RESET_FILE}"
    clobber-log -- "Leave developer mode"
  fi
else
  if crossystem 'devsw_boot?1' && ! crossystem 'mainfw_type?recovery'; then
    # We're transitioning from verified boot to dev mode.
    chromeos-boot-alert enter_dev
    echo "keepimg" >"${RESET_FILE}"
    clobber-log -- "Enter developer mode"
  fi
fi

if [ -O ${RESET_FILE} ]; then
  ARGS="$(cat ${RESET_FILE})"
  exec clobber-state "$ARGS"
fi

# Checks and updates stateful partition.
dev_update_stateful_partition

# Make sure unencrypted stateful partition has the needed common directories.
# Any non-common directories should be created in the device implementation of
# "mount_var_and_home_chronos".
for d in home home/chronos home/root home/user \
         unencrypted unencrypted/cache unencrypted/preserve; do
  mkdir -p -m 0755 "/mnt/stateful_partition/${d}"
  check_directory "/mnt/stateful_partition/${d}"
done

# Mount /home.  This mount inherits nodev,noexec,nosuid from
# /mnt/stateful_partition above.
mount_or_fail --bind /mnt/stateful_partition/home /home

remember_mount /var
remember_mount /home/chronos
do_mount_var_and_home_chronos || cleanup_mounts "var and home"

# If /var is too full, delete the logs so the device can boot successfully.
# It is possible that the fullness of /var was not due to logs, but that
# is very unlikely. If such a thing happens, we have a serious problem
# which should not be covered up here.
if is_var_full; then
  rm -r -f /var/log
  echo "Startup.ReclaimFullVar" > /mnt/stateful_partition/.reclaim_full_var
fi

# Gather log if needed.
dev_gather_logs

# /run is now tmpfs used for runtime data. Make sure /var/run and /var/lock
# are sym links to /run and /run/lock respectively for backwards compatibility.
rm -rf /var/run /var/lock || \
    cleanup_mounts "failed to delete /var/run and /var/lock"
ln -s /run /var/run
ln -s /run/lock /var/lock

# Make sure required /var subdirectories exist.
mkdir -p -m 0755 /var/cache /var/db /var/empty /var/log/metrics \
                 /var/spool /var/tmp /var/lib/misc

# Before operating on them, verify that all stateful partition paths are
# directories (as opposed to say, symlinks).
for d in /var/cache /var/db /var/empty /var/log /var/log/metrics \
         /var/spool /var/tmp /var/lib /var/lib/misc /home/chronos /home/root; do
  check_directory "${d}"
done

# /var/tmp must be world-writable and sticky
chmod 1777 /var/tmp
# /home/root must be group-writable and sticky
chmod 1771 /home/root
# Selected directories must belong to the chronos user.
chown chronos:chronos /home/chronos /var/log/metrics
# rsyslog needs to be able to create new logfiles, but not delete other logs
chgrp syslog /var/log
chmod 1775 /var/log
# /var/cache, /var/db, and /var/empty may already exist with wrong permissions.
# Force the correct ones.
chmod 0755 /var/cache /var/db /var/empty /var/spool /var/lib /var/lib/misc
# Make sure the empty dir stays empty (only works on ext4).
chattr +i /var/empty || :

# "--make-shared" to let ARC container access mount points under /media.
mount --make-shared -n -t tmpfs -o nodev,noexec,nosuid media /media

# Mount dev packages.
dev_mount_packages

bootstat post-startup

# Always return success to avoid killing init
exit 0