#!/bin/sh
# Copyright (C) 2016 Arista Networks, Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Aboot stage 0 boot script
#
# This boot0 script can be used in different scenario
#  - Installation and boot from Aboot (manual or reboot on a new image)
#  - EOS to SONiC fast-reboot (installation and kexec in EOS)
#  - SONiC to SONiC fast-reboot (installation and kexec in SONiC)
#
# Use it this way:
#   - swipath=path/to/swi install=true boot0
#   - swipath=path/to/swi install=true force=true boot0
#   - swipath=path/to/swi kexec=true boot0
#
# The logic defaults to the first scenario but providing extra environment variable
# will affect the behavior of the script.
# The list of variables is maintained here
#   - KERNEL : relative path to the kernel to execute
#   - INITRD : relative path to the initrd to load
#   - CMDLINE : place to find the default kernel cmdline to use for the platform
#   - VERBOSE : setting it to 1 will enable debug traces
#
# By default the boot0 script will behave for an Aboot based behavior.
# Options can be provided to only run some features of this script.
#
# Extra kernel parameters can be provided at runtime by the user by adding them
# into the kernel-params file.
#
# Secureboot of SONiC SWI images is also supported.
# In such cases, there will only be a partial install on the flash.
# SONiC will be mostly booting in RAM as a live operating system.

# All templated variables should be declared here
image_name="image-%%IMAGE_VERSION%%"
dockerfs="{{ FILESYSTEM_DOCKERFS }}"
boot_image="{{ ABOOT_BOOT_IMAGE }}"
installer_image="sonic.swi"
docker_dir="{{ DOCKERFS_DIR }}"

do_not_clean="do-not-clean"
kernel_params="kernel-params"

aboot_machine="arista_unknown"

info() { printf "%04.2f: $@\n" "$(cut -f1 -d' ' /proc/uptime)"; }
err() { info "Error: $@"; }
warn() { info "Warning: $@"; }

if [ $# -ne 0 ]; then
    echo "usage: $0 (see code)"
    exit 1
fi

mountpoint_for_file() {
   local file="$1"
   df "$file" | tail -1 | tr -s " " | cut -d ' ' -f6
}

# extract mount point from the swi path, e.g., /mnt/flash/sonic.swi --> /mnt/flash
if [ -z "$target_path" ]; then
    if [ -z "$swipath" ]; then
       err "target_path= is required when swipath= is not provided"
       exit 1
    fi
    target_path=$(mountpoint_for_file "$swipath")
fi
image_path="$target_path/$image_name"
hook_path="$image_path/platform/hooks"
data_path="$image_path/platform/data"
boot_image_path="$image_path/$boot_image"
installer_image_path="$image_path/$installer_image"

boot_config="$target_path/boot-config"

cmdline_allowlist="crashkernel hwaddr_ma1 sonic_fips"

# for backward compatibility with the sonic_upgrade= behavior
install="${install:-${sonic_upgrade:-}}"

is_secureboot_enabled() {
    if $in_aboot; then
        if [ -x /bin/securebootctl ] && securebootctl sb -display | grep -q "Secure Boot enabled"; then
            return 0
        fi
        return 1
    else
        if grep -q aboot.secureboot /proc/cmdline; then
            return 0
        fi
        # FIXME: EOS is not handled here
        return 1
    fi
}

clean_flash() {
    ## Remove all the other unnecssary files except swi file, boot-config
    for f in $(ls -A $target_path); do
        if [ $f != "${swipath##*/}" ] &&
           [ $f != "boot-config" ] &&
           [ $f != "preserve-installer" ] &&
           [ $f != "$kernel_params" ] &&
           [ $f != "aquota.user" ] &&
           [ $f != "old_config" ] &&
           [ $f != "minigraph.xml" ] &&
           [ $f != "snmp.yml" ] &&
           [ $f != "acl.json" ] &&
           [ $f != "port_config.json" ]
        then
            rm -rf "$target_path/$f"
        fi
    done
}

in_array() {
    local value="$1"
    shift

    for other in $@; do
        if [ "$value" = "$other" ]; then
            return 0
        fi
    done

    return 1
}

update_boot_config() {
    local key="$1"
    local value="$2"

    if grep "$key" "$boot_config" 2>&1 > /dev/null; then
        sed -i "s#^$key=.*\$#$key=$value#" "$boot_config"
    else
        echo "$key=$value" >> "$boot_config"
    fi
}

get_boot_config() {
    local key="$1"

    sed -n "s#^$key=##p" "$boot_config" || :
}

update_next_boot() {
    local default="$(get_boot_config SWI_DEFAULT)"

    if [ -z "$default" ]; then
        warn "boot-config has no variable SWI_DEFAULT"
    else
        info "Next reboot will use $default"
        update_boot_config SWI "$default"
    fi
}

get_sorted_hooks() {
    echo $(find "$1" -name '[0-9][0-9]-*' -type f)
}

run_hooks() {
    if [ -d "$hook_path/$1" ]; then
        for hook in $(get_sorted_hooks "$hook_path/$1"); do
            if [ ! -z "$hook" ]; then
                info "Running hook $(basename $hook)"
                . "$hook"
            fi
        done
    fi
}

get_uuid_for() {
    local dev="$1"

    if type lsblk 2>&1 > /dev/null; then
       lsblk "$dev" -n --output UUID
    elif type blkid 2>&1 > /dev/null; then
       blkid | grep "^$dev" | sed -n 's/^.* UUID="//p' | sed 's/".*$//'
    fi
}

cmdline_append() {
    cat >> /tmp/append
}

cmdline_clear() {
    echo -n > /tmp/append
}

cmdline_add() {
    echo "$@" >> /tmp/append
}

cmdline_has() {
    grep -q "$1" /tmp/append
}

cmdline_echo() {
    # echo trims and remove whitespace duplicates
    echo $(cat /tmp/append | tr '\n' ' ')
}

cmdline_get() {
    # extract last matching value for key
    sed -nr "s/.*$1=([^ ]+).*/\1/p" /tmp/append | tail -n 1
}

find_first_kernel_under() {
    local path="$1"
    find "$path" -name 'vmlinuz-*' -type f | head -n 1
}

find_first_initrd_under() {
    local path="$1"
    find "$path" -name 'initrd.img-*' -type f | head -n 1
}

is_file_in_memory() {
    local file="$1"
    local filemnt=$(mountpoint_for_file "$file")
    local filemntfs=$(mount | grep " $filemnt " | cut -f5 -d' ')

    case "$filemntfs" in
       tmpfs|ramfs) return 0;;
       *) return 1;;
    esac
}

get_tmpfs() {
    local tmpfs="$(mktemp -d)"

    mkdir -p "$tmpfs"
    if ! $in_aboot && ! mount | grep -q ' /tmp type tmpfs'; then
        # mount a real tmpfs on /tmp/xxx if /tmp is not one already.
        mount -t tmpfs "$(dirname $tmpfs)" "$tmpfs"
    fi
    echo "$tmpfs"
}

clean_tmpfs() {
    local tmpfs="$1"

    case "$tmpfs" in
       /tmp) return 0;;
       /tmp/*);; # only cleanup tmpfs created by this script
       *) return 0;;
    esac

    if mount | grep -q "$tmpfs"; then
        umount "$tmpfs" || :
    fi
}

move_swi_to_tmpfs() {
    local oldswi="$1"

    if is_file_in_memory "$oldswi"; then
       echo "$oldswi"
       return 0
    fi

    local tmpfs="$(get_tmpfs)"
    local newswi="$tmpfs/$(basename "$oldswi")"

    mv "$oldswi" "$newswi"
    echo "$newswi"
}

cleanup_swi_tmpfs() {
   rm -f "$swipath"
   clean_tmpfs "$(mountpoint_for_file "$swipath")"
}

mount_relpath() {
    local abspath="$1"
    local mountpath="$(df "$abspath" | sed -nr '/\//s/^.* ([^ ]+)$/\1/p')"

    echo "$abspath" | sed "s#^$mountpath/##"
}

zip_file_offset() {
    local zipfile="$1"
    local filename="$2"

    if $in_aboot; then
        unzip -qqf "$zipfile" "$filename"
    else
        local hexoffset="$(zipdetails "$zipfile" | sed -En "/Filename +'$filename'/,/^$/p" | sed -En 's/^([^ ]+) PAYLOAD$/\1/p')"
        echo "$((0x$hexoffset))"
    fi
}

SWI_ALREADY_INSTALLED=0
SWI_NOT_INSTALLED=1
SWI_VERSION_MISMATCH=2
SWI_OTHER_VARIANT_INSTALLED=3

is_swi_installed() {
    local swi_path="$1"
    local swi_version="$(unzip -qp "$swi_path" .imagehash)"
    local local_version="$(cat $image_path/.imagehash 2>/dev/null || :)"

    if [ -z "$local_version" ]; then
        # no image installed for this version
        return $SWI_NOT_INSTALLED
    fi

    if [ "$swi_version" != "$local_version" ]; then
        warn "Installed image has a different version than $swipath"
        return $SWI_VERSION_MISMATCH
    fi

    if $secureboot; then
        if [ -s "$installer_image_path" ]; then
            # secureboot image already installed
            return $SWI_ALREADY_INSTALLED
        else
            # regular image of the same version already installed
            return $SWI_OTHER_VARIANT_INSTALLED
        fi
    else
        if [ -s "$boot_image_path" ]; then
            # regular image already installed
            return $SWI_ALREADY_INSTALLED
        else
            # secureboot image of the same version already installed
            return $SWI_OTHER_VARIANT_INSTALLED
        fi
    fi
}

extract_image() {
    info "Moving swi to a tmpfs"
    ## Avoid problematic flash usage spike on older systems, also improves I/O
    swipath="$(move_swi_to_tmpfs "$swipath")"

    info "Extracting swi content"
    ## Unzip the image except boot0 and dockerfs archive
    unzip -oq "$swipath" -x boot0 "$dockerfs" "platform.tar.gz" -d "$image_path"

    ## Extract the platform.tar.gz
    info "Extracting platform.tar.gz"
    mkdir -p "$image_path/platform"
    unzip -oqp "$swipath" "platform.tar.gz" | tar xzf - -C "$image_path/platform" $TAR_EXTRA_OPTION

    ## detect rootfs type
    local mountstr="$(grep " $target_path " /proc/mounts)"
    local rootdev="$(echo $mountstr | cut -f1 -d' ')"
    rootfs_type="$(echo $mountstr | cut -d' ' -f3)"

    info "Extracting $dockerfs from swi"
    ## Unpacking dockerfs delayed
    ## 1. when disk is vfat as it does not support symbolic link
    ## 2. when disk is small, expand it into ramfs during initrd
    if [ "$rootfs_type" != "vfat" ] && ! cmdline_has docker_inram=on; then
        mkdir -p "$image_path/$docker_dir"

        if [ -n "$install" ]; then
            TAR_EXTRA_OPTION="--numeric-owner --warning=no-timestamp"
        fi

        ## extract docker archive
        unzip -oqp "$swipath" "$dockerfs" | tar xzf - -C "$image_path/$docker_dir" $TAR_EXTRA_OPTION
    else
        ## save dockerfs archive in the image directory
        unzip -oq "$swipath" "$dockerfs" -d "$image_path"
        info "Unpacking $dockerfs delayed to initrd because $target_path is $rootfs_type or docker_inram is on"
    fi

    ## remove installer since it's not needed anymore
    if $preserve_installer; then
        info "Preserving installer under $installer_image_path"
        mv "$swipath" "$installer_image_path"
        chmod a+r "$installer_image_path"
    else
        info "Remove installer"
        cleanup_swi_tmpfs "$swipath"
    fi

    ## use new reduced-size boot swi
    local swi_boot_path="flash:$image_name/$boot_image"
    update_boot_config SWI "$swi_boot_path"
    update_boot_config SWI_DEFAULT "$swi_boot_path"

    ## sync disk operations
    sync
}

extract_image_secureboot() {
    info "Extracting necessary swi content"
    # NOTE: boot/ is not used by the boot process but only extracted for kdump
    unzip -oq "$swipath" 'boot/*' .imagehash -d "$image_path"

    ## Extract platform.tar.gz
    info "Extracting platform.tar.gz"
    mkdir -p "$image_path/platform"
    unzip -oqp "$swipath" "platform.tar.gz" | tar xzf - -C "$image_path/platform" $TAR_EXTRA_OPTION

    info "Installing swi under $installer_image_path"
    mv "$swipath" "$installer_image_path"
    chmod a+r "$installer_image_path"
    swipath="$installer_image_path"

    local swi_boot_path="flash:$image_name/$installer_image"
    update_boot_config SWI "$swi_boot_path"
    update_boot_config SWI_DEFAULT "$swi_boot_path"

    sync
}

prepare_image_secureboot() {
    local boot_tmpfs="$(get_tmpfs)"

    info "Extracting boot content in tmpfs"
    unzip -oq "$swipath" 'boot/*' -d "$boot_tmpfs"

    info "Generating machine.conf and cmdline"
    write_secureboot_configs

    sync

    # override environment variables preventing external tamper on kernel execution
    CMDLINE="$(cmdline_echo) $ENV_EXTRA_CMDLINE"
    KERNEL="$(find_first_kernel_under "$boot_tmpfs")"
    INITRD="$(find_first_initrd_under "$boot_tmpfs")"
}

write_machine_config() {
    ## Detect SKU and create a hardware description file
    aboot_version=$(cmdline_get Aboot | sed 's/^.*norcal.-//')
    if [ -x /bin/sysinit ]; then
       aboot_build_date=$(stat -c %y /bin/sysinit | sed 's/ /T/')
    else
       aboot_build_date="unknown"
    fi
    cat <<EOF > ${target_path}/machine.conf
aboot_version=$aboot_version
aboot_vendor=arista
aboot_platform=x86_64-$aboot_machine
aboot_machine=$aboot_machine
aboot_arch=x86_64
aboot_build_date=$aboot_build_date
EOF
    chmod a+r "${target_path}/machine.conf"
}

read_system_eeprom() {
    if [ -x /bin/readprefdl ] && [ -f /tmp/.system-prefdl ]; then
        readprefdl -f /tmp/.system-prefdl -d > $target_path/.system-prefdl
    elif [ -f /etc/prefdl ]; then
        cp /etc/prefdl $target_path/.system-prefdl
        chmod a+r $target_path/.system-prefdl
    fi
}

write_platform_specific_cmdline() {
    local platform="$(cmdline_get platform)"
    local sid="$(cmdline_get sid | sed 's/Ssd$//')"

    # set varlog size to 100MB
    local varlog_size=100

    # sonic_mode is set to fixed by default.
    sonic_mode="fixed"
    supervisor_mode="supervisor"
    linecard_mode="linecard"

    # detect the size of the flash partition from name in Aboot/EOS/SONiC
    local flash_size=$(($(df "$target_path" | tail -1 | tr -s ' ' | cut -f2 -d' ') / 1000))

    if [ "$platform" = "raven" ]; then
        # Assuming sid=Cloverdale
        aboot_machine=arista_7050_qx32
        flash_size=2000
        cmdline_add modprobe.blacklist=radeon,sp5100_tco
        cmdline_add acpi=off
    fi
    if [ "$platform" = "crow" ]; then
        # Assuming sid=Clearlake
        aboot_machine=arista_7050_qx32s
        cmdline_add modprobe.blacklist=radeon,sp5100_tco
    fi
    if in_array "$sid" "Upperlake" "UpperlakeES" "UpperlakeElite"; then
        aboot_machine=arista_7060_cx32s
        flash_size=3700
    fi
    if [ "$sid" = "UpperlakePlus" ]; then
        aboot_machine=arista_7060cx2_32s
        flash_size=3700
    fi
    if [ "$sid" = "Gardena" ] || [ "$sid" = "GardenaE" ]; then
        aboot_machine=arista_7260cx3_64
        flash_size=28000
    fi
    if [ "$sid" = "Alhambra" ]; then
        aboot_machine=arista_7170_64c
        flash_size=28000
        cmdline_add hugepages=128
    fi
    if [ "$sid" = "Mineral" ]; then
        aboot_machine=arista_7170_32c
        flash_size=28000
        cmdline_add hugepages=128
    fi
    if [ "$sid" = "MineralD" ]; then
        aboot_machine=arista_7170_32cd
        flash_size=28000
        cmdline_add hugepages=128
    fi
    if [ "$sid" = "Woodleaf" ]; then
        aboot_machine=arista_7170b_64c
        cmdline_add hugepages=128
    fi
    if [ "$sid" = "Lodoga" ]; then
        aboot_machine=arista_7050cx3_32s
    fi
    if [ "$sid" = "Marysville" ]; then
        aboot_machine=arista_7050sx3_48yc8
        flash_size=7382
    fi
    if [ "$sid" = "Marysville10" ]; then
        aboot_machine=arista_7050sx3_48c8
        flash_size=7382
    fi
    if [ "$sid" = "BlackhawkO" ]; then
        aboot_machine=arista_7060px4_32
        flash_size=28000
    fi
    if [ "$sid" = "BlackhawkDD" ] || [ "$sid" = "BlackhawkDDM" ]; then
        aboot_machine=arista_7060dx4_32
        flash_size=28000
    fi
    if in_array "$sid" "PikeIslandZ" "PikeIslandZ-F" "PikeIslandZ-2F" "PikeIslandZ-R" "PikeIslandZ-2R"; then
        aboot_machine=arista_720dt_48s
    fi
    if [ "$sid" = "BlackhawkT4O" ]; then
        aboot_machine=arista_7050px4_32s
    fi
    if [ "$sid" = "BlackhawkT4DD" ]; then
        aboot_machine=arista_7050dx4_32s
    fi
    if [ "$sid" = "Smartsville" ]; then
        aboot_machine=arista_7280cr3_32p4
    fi
    if [ "$sid" = "SmartsvilleBK" ]; then
        aboot_machine=arista_7280cr3k_32p4
    fi
    if [ "$sid" = "SmartsvilleBkMs" ] || [ "$sid" = "SmartsvilleBkMsTpm" ]; then
        aboot_machine=arista_7280cr3mk_32p4
    fi
    if [ "$sid" = "SmartsvilleDD" ]; then
        aboot_machine=arista_7280cr3_32d4
    fi
    if [ "$sid" = "SmartsvilleDDBK" ]; then
        aboot_machine=arista_7280cr3k_32d4
    fi
    if [ "$sid" = "SmartsvilleDDBkMs" ] || [ "$sid" = "SmartsvilleDDBkMsTpm" ]; then
        aboot_machine=arista_7280cr3mk_32d4
    fi
    if [ "$sid" = "CatalinaP" ]; then
        aboot_machine=arista_7060px5_64s
    fi
    if [ "$sid" = "CatalinaDD" ]; then
        aboot_machine=arista_7060dx5_64s
    fi
    if [ "$sid" = "Clearwater2" ]; then
        aboot_machine=arista_7800r3_48cq2_lc
        sonic_mode="$linecard_mode"
    fi
    if [ "$sid" = "Clearwater2Ms" ]; then
        aboot_machine=arista_7800r3_48cqm2_lc
        sonic_mode="$linecard_mode"
    fi
    if [ "$sid" = "WolverineQCpu" ]; then
        aboot_machine=arista_7800r3a_36d2_lc
        sonic_mode="$linecard_mode"
    fi
    if [ "$sid" = "WolverineQCpuBk" ]; then
        aboot_machine=arista_7800r3ak_36d2_lc
        sonic_mode="$linecard_mode"
    fi
    if [ "$sid" = "WolverineQCpuMs" ]; then
        aboot_machine=arista_7800r3a_36dm2_lc
        sonic_mode="$linecard_mode"
    fi
    if [ "$sid" = "WolverineQCpuBkMs" ]; then
        aboot_machine=arista_7800r3ak_36dm2_lc
        sonic_mode="$linecard_mode"
    fi
    if [ "$sid" = "OtterLake" ]; then
        aboot_machine=arista_7800_sup
        flash_size=30000
        sonic_mode=$supervisor_mode
    fi
    if [ "$sid" = "SmartsvilleBkMs" ]; then
        aboot_machine=arista_7280cr3mk_32p4
        flash_size=7382
    fi
    if in_array "$platform" "rook" "magpie" "woodpecker" "sprucefish"; then
        cmdline_add tsc=reliable
        cmdline_add pcie_ports=native
        cmdline_add rhash_entries=1
        cmdline_add usb-storage.delay_use=0
        cmdline_add reassign_prefmem
    fi
    if in_array "$platform" "rook" "sprucefish"; then
        cmdline_add iommu=on
        cmdline_add intel_iommu=on
        cmdline_add intel_idle.max_cstate=0
        read_system_eeprom
    fi
    if in_array "$platform" "crow" "magpie"; then
        cmdline_add amd_iommu=off
        cmdline_add modprobe.blacklist=snd_hda_intel,hdaudio
        read_system_eeprom
    fi
    if in_array "$platform" "woodpecker"; then
        cmdline_add modprobe.blacklist=snd_hda_intel,hdaudio
        read_system_eeprom
    fi
    if in_array "$platform" "lorikeet" "hedgehog"; then
        cmdline_add processor.max_cstate=1
        cmdline_add reassign_prefmem
        read_system_eeprom
    fi
    if in_array "$platform" "prairieisland"; then
        read_system_eeprom
    fi

    if [ $flash_size -ge 28000 ]; then
        varlog_size=4096
    elif [ $flash_size -gt 4000 ]; then
        varlog_size=400
    else
        varlog_size=256
        cmdline_add logs_inram=on
        if [ $flash_size -le 2000 ]; then
            # enable docker_inram for switches with less than 2G of flash
            varlog_size=128
            cmdline_add docker_inram=on
        fi
    fi

    cmdline_add "varlog_size=$varlog_size"

    cmdline_add "sonic.mode=$sonic_mode"
}

write_image_specific_cmdline() {
    # security
    cmdline_add security=apparmor
    cmdline_add apparmor=1

    # fs configuration
    cmdline_add rw

    # disable deterministic interface naming
    cmdline_add net.ifnames=0

    # disable unified cgroup hierarchy to workaround dockerd limitation
    cmdline_add systemd.unified_cgroup_hierarchy=0

    # verbosity
    cmdline_add quiet
    # Start showing systemd information from the first failing unit if any.
    # systemd.show_status=false or quiet can be used to silence systemd entierly
    cmdline_add systemd.show_status=auto

    # Pass the MAC address to the new kernel as a command line parameter. This makes it
    # possible to restore the MAC address in the new kernel without requiring driver modifications.
    if [ -f /sys/class/net/ma1/address ]; then
        cmdline_add "hwaddr_ma1=$(cat /sys/class/net/ma1/address)"
    elif [ -f /sys/class/net/eth0/address ]; then
        cmdline_add "hwaddr_ma1=$(cat /sys/class/net/eth0/address)"
    else
        err "Management port not found."
    fi

    # Obtain root partition uuid
    local mountstr="$(mount | grep " $target_path ")"
    local rootdev="$(echo $mountstr | cut -f1 -d' ')"
    local rootfstype="$(echo $mountstr | cut -f5 -d' ')"
    local rootuuid="$(get_uuid_for $rootdev)"
    if [ -z "$rootuuid" ] || [ "$rootfstype" = "vfat" ] ; then
        cmdline_add "root=$rootdev"
    else
        cmdline_add "root=UUID=$rootuuid"
    fi
}

write_default_cmdline() {
    local delimiter="cmdline-aboot-end"

    cmdline_clear

    if $in_aboot; then
        # generate the default kernel parameters for the platform
        cat /etc/cmdline | sed "/^\(${bootconfigvars// /\|}\|crashkernel\|loglevel\|ignore_loglevel\)\(\$\|=\)/d;/^\$/d" | cmdline_append
    elif grep -q "$delimiter" /proc/cmdline; then
        # we are on a recent sonic image using delimiter. extracting the part of the
        # cmdline coming from aboot is trivial.
        cat /proc/cmdline | sed -E "s/^(.*) $delimiter .*$/\1/" | tr ' ' '\n' | cmdline_append
    else
        # we are either on SONiC or EOS and the commandline doesn't have a delimiter
        # for the Aboot part. Take an educated guess at a right delimiter.
        # Subject to breakage if EOS or SONiC cmdline change.
        cat /proc/cmdline | sed -E 's/^(.*) rw .*$/\1/' | tr ' ' '\n' | cmdline_append
    fi

    cmdline_add "$delimiter"
}

write_cmdline() {
    # use extra parameters from kernel-params hook if the file exists
    if [ -f "$target_path/$kernel_params" ] && ! $secureboot; then
        info "Loading extra kernel parameters from $kernel_params"
        cat "$target_path/$kernel_params" | cmdline_append
    fi

    # FIXME: sonic sometimes adds extra kernel parameters from user space
    #        this is unsafe but some will be kept as part of the regular boot
    if [ -f "$image_path/kernel-cmdline" ]; then
        for field in $cmdline_allowlist; do
           cat "$image_path/kernel-cmdline" | tr ' ' '\n' | grep -E "$field" | tail -n 1 | cmdline_append
        done
    fi

    # FIXME: legacy configuration files used by fast-reboot and eos2sonic
    #        these should be deprecated over time.
    cmdline_echo > "$image_path/kernel-cmdline"
    cmdline_echo | sed 's/ cmdline-aboot-end.*$//' > "$target_path/kernel-params-base"
}

write_common_configs() {
    write_default_cmdline
    write_platform_specific_cmdline
    write_image_specific_cmdline
    write_machine_config
}

write_secureboot_configs() {
    write_common_configs
    cmdline_add "loop=$(mount_relpath "$installer_image_path")"
    cmdline_add loopfstype=squashfs
    cmdline_add "loopoffset=$(zip_file_offset "$installer_image_path" fs.squashfs)"
    cmdline_add docker_inram=on
    cmdline_add secure_boot_enable=y
    cmdline_add aboot.secureboot=enabled
    # setting panic= has the side effect of disabling the initrd shell on error
    cmdline_add panic=0
    write_cmdline
}

write_regular_configs() {
    write_common_configs
    cmdline_add "loop=$image_name/fs.squashfs"
    cmdline_add loopfstype=squashfs
    write_cmdline
}

run_kexec() {
    local cmdline="${CMDLINE:-$(cmdline_echo) $ENV_EXTRA_CMDLINE}"
    local kernel="${KERNEL:-$(find_first_kernel_under "$image_path/boot")}"
    local initrd="${INITRD:-$(find_first_initrd_under "$image_path/boot")}"

    if $verbose; then
        # show systemd showdown sequence when verbose is set
        cmdline="$(echo "$cmdline" | sed 's/systemd.show_status=auto/systemd.show_status=true/')"
    fi

    if $debug; then
        # enable initrd debug as well as kernel verbose output
        cmdline="$(echo "$cmdline" | sed 's/ quiet//')"
        cmdline="$cmdline debug loglevel=7 log_buf_len=8M printk.devmsg=on"
    fi

    sync
    kexec --load --initrd="$initrd" --append="$cmdline" "$kernel"

    ( [ -z "$testonly" ] && [ -z "$loadonly" ] ) || exit 0
    info "Kexecing..."
    kexec --exec
}

secureboot_install() {
    if [ -e "$image_path" ]; then
        warn "Image folder $image_path already exist (likely regular install)"
    fi

    mkdir -p "$image_path"

    info "Installing image as $installer_image_path"
    extract_image_secureboot
}

regular_install() {
    if [ -e "$image_path" ]; then
        warn "Image folder $image_path already exist (likely secureboot install)"
    fi

    mkdir -p $image_path

    info "Generating boot-config, machine.conf and cmdline"
    write_regular_configs "$image_path"

    info "Installing image under $image_path"
    extract_image

    run_hooks post-install
}

secureboot_boot() {
    # boot material is extracted and generated in RAM.
    # SONiC starts as a live OS.
    info "Preparing image for secureboot"
    prepare_image_secureboot
    update_next_boot
    run_kexec
}

regular_boot() {
    # boot uses the image installed on the flash
    write_regular_configs "$image_path"
    run_hooks pre-kexec
    update_next_boot
    run_kexec
}


# In Aboot no option will be provided therefore these are the default values to use
in_aboot=true
do_clean=true
do_install=true
do_kexec=true

# prevent the flash from being cleaned if the do-not-clean file exists
if [ -f "$target_path/$do_not_clean" ]; then
    do_clean=false
fi

# Parse the cmdline options (used from EOS or from SONiC)
if [ ! -z "$install" ]; then
    # install from SONiC or EOS
    in_aboot=false
    do_clean=false
    do_kexec=false
elif [ ! -z "$kexec" ]; then
    # kexec from SONiC or EOS
    in_aboot=false
    do_install=false
    do_clean=false
fi

# Make sure boot-config exists to avoid noise
touch "$boot_config"

# Verbosity can be defined by the caller, default to false otherwise
verbose=${verbose:-false}
debug=${debug:-false}
if [ -f "$target_path/verbose-boot" ] ||
   [ "$(get_boot_config VERBOSE)" = "1" ] ||
   ! $in_aboot; then
    verbose=true
fi
if [ -f "$target_path/debug-boot" ] || [ "$(get_boot_config DEBUG)" = "1" ]; then
    verbose=true
    debug=true
fi

# behavioral configuration for secureboot
# can be overidden by passing secureboot=true via env
if [ -z "$secureboot" ]; then
    if is_secureboot_enabled; then
        secureboot=true
    else
        secureboot=false
    fi
fi

# preserve original installer during regular install when set
preserve_installer=false
if [ -f "$target_path/preserve-installer" ] ||
   [ "$(get_boot_config PRESERVE_INSTALLER)" = "1" ]; then
    preserve_installer=true
fi

# enable shell debug mode to get the most verbosity
if $verbose; then
    set -x
fi

# install the image if newer
if $do_install; then
    if ! unzip -ql "$swipath" 2>&1 > /dev/null; then
        err "The swipath= environment variable does not point to a valid SWI"
        exit 1
    fi

    swi_installed=0
    is_swi_installed "$swipath" || swi_installed=$?

    if [ "$swi_installed" -ne $SWI_ALREADY_INSTALLED ] || [ -n "$force" ]; then
        if [ "$swi_installed" -eq $SWI_VERSION_MISMATCH ] || [ -n "$force" ]; then
            warn "Removing existing installation folder $image_path"
            rm -rf $image_path
        fi
        if [ "$swi_installed" -ne $SWI_OTHER_VARIANT_INSTALLED ] && $do_clean; then
            info "Cleaning flash content $target_path"
            clean_flash
        fi
        if $secureboot; then
            secureboot_install
        else
            regular_install
        fi
    else
        info "Using previously installed image"
    fi
fi

# chainloading using kexec
if $do_kexec; then
    if $secureboot; then
       secureboot_boot
    else
       regular_boot
    fi
fi