Openwrt 的sysupgrade脚本

Openwrt中的sysupgrade脚本提供了固件升级的快捷方式，该脚本位于： /sbin/sysupgrade
脚本内容：

#!/bin/sh
. /lib/functions.sh
. /lib/functions/system.sh

# initialize defaults
RAMFS_COPY_BIN=""       # extra programs for temporary ramfs root
RAMFS_COPY_DATA=""      # extra data files
export MTD_CONFIG_ARGS=""
export INTERACTIVE=0
export VERBOSE=1
export SAVE_CONFIG=1
export SAVE_OVERLAY=0
export DELAY=
export CONF_IMAGE=
export CONF_BACKUP_LIST=0
export CONF_BACKUP=
export CONF_RESTORE=
export NEED_IMAGE=
export HELP=0
export FORCE=0
export TEST=0

# parse options
while [ -n "$1" ]; do
        case "$1" in
                -i) export INTERACTIVE=1;;
                -d) export DELAY="$2"; shift;;
                -v) export VERBOSE="$(($VERBOSE + 1))";;
                -q) export VERBOSE="$(($VERBOSE - 1))";;
                -n) export SAVE_CONFIG=0;;
                -c) export SAVE_OVERLAY=1;;
                -b|--create-backup) export CONF_BACKUP="$2" NEED_IMAGE=1; shift;;
                -r|--restore-backup) export CONF_RESTORE="$2" NEED_IMAGE=1; shift;;
                -l|--list-backup) export CONF_BACKUP_LIST=1; break;;
                -f) export CONF_IMAGE="$2"; shift;;
                -F|--force) export FORCE=1;;
                -T|--test) export TEST=1;;
                -h|--help) export HELP=1; break;;
                -*)
                        echo "Invalid option: $1"
                        exit 1
                ;;
                *) break;;
        esac
        shift;
done

export CONFFILES=/tmp/sysupgrade.conffiles
export CONF_TAR=/tmp/sysupgrade.tgz

export ARGV="$*"
export ARGC="$#"

[ -z "$ARGV" -a -z "$NEED_IMAGE" -o $HELP -gt 0 ] && {
        cat <<EOF
Usage: $0 [<upgrade-option>...] <image file or URL>
       $0 [-q] [-i] <backup-command> <file>

upgrade-option:
        -d <delay>   add a delay before rebooting
        -f <config>  restore configuration from .tar.gz (file or url)
        -i           interactive mode
        -c           attempt to preserve all changed files in /etc/
        -n           do not save configuration over reflash
        -T | --test
                     Verify image and config .tar.gz but do not actually flash.
        -F | --force
                     Flash image even if image checks fail, this is dangerous!
        -q           less verbose
        -v           more verbose
        -h | --help  display this help

backup-command:
        -b | --create-backup <file>
                     create .tar.gz of files specified in sysupgrade.conf
                     then exit. Does not flash an image. If file is ‘-‘,
                     i.e. stdout, verbosity is set to 0 (i.e. quiet).
        -r | --restore-backup <file>
                     restore a .tar.gz created with sysupgrade -b
                     then exit. Does not flash an image. If file is ‘-‘,
                     the archive is read from stdin.
        -l | --list-backup
                     list the files that would be backed up when calling
                     sysupgrade -b. Does not create a backup file.

EOF
        exit 1
}

[ -n "$ARGV" -a -n "$NEED_IMAGE" ] && {
        cat <<-EOF
                -b|--create-backup and -r|--restore-backup do not perform a firmware upgrade.
                Do not specify both -b|-r and a firmware image.
        EOF
        exit 1
}

# prevent messages from clobbering the tarball when using stdout
[ "$CONF_BACKUP" = "-" ] && export VERBOSE=0

add_uci_conffiles() {
        local file="$1"
        ( find $(sed -ne ‘/^[[:space:]]*$/d; /^#/d; p‘                 /etc/sysupgrade.conf /lib/upgrade/keep.d/* 2>/dev/null)                 -type f -o -type l 2>/dev/null;
          opkg list-changed-conffiles ) | sort -u > "$file"
        return 0
}

add_overlayfiles() {
        local file="$1"
        if [ -d /overlay/upper ]; then
                local overlaydir="/overlay/upper"
        else
                local overlaydir="/overlay"
        fi
        find $overlaydir/etc/ -type f -o -type l | sed                 -e ‘s,^/overlay/,/,‘                 -e ‘\,/META_[a-zA-Z0-9]*$,d‘                 -e ‘\,/functions.sh$,d‘                 -e ‘\,/[^/]*-opkg$,d‘         > "$file"
        return 0
}

# hooks
sysupgrade_image_check="platform_check_image"
[ $SAVE_OVERLAY = 0 -o ! -d /overlay/etc ] &&         sysupgrade_init_conffiles="add_uci_conffiles" ||         sysupgrade_init_conffiles="add_overlayfiles"

include /lib/upgrade

[ "$1" = "nand" ] && nand_upgrade_stage2 $@

do_save_conffiles() {
        local conf_tar="${1:-$CONF_TAR}"

        [ -z "$(rootfs_type)" ] && {
                echo "Cannot save config while running from ramdisk."
                ask_bool 0 "Abort" && exit
                return 0
        }
        run_hooks "$CONFFILES" $sysupgrade_init_conffiles
        ask_bool 0 "Edit config file list" && vi "$CONFFILES"

        v "Saving config files..."
        [ "$VERBOSE" -gt 1 ] && TAR_V="v" || TAR_V=""
        tar c${TAR_V}zf "$conf_tar" -T "$CONFFILES" 2>/dev/null

        rm -f "$CONFFILES"
}

if [ $CONF_BACKUP_LIST -eq 1 ]; then
        add_uci_conffiles "$CONFFILES"
        cat "$CONFFILES"
        rm -f "$CONFFILES"
        exit 0
fi

if [ -n "$CONF_BACKUP" ]; then
        do_save_conffiles "$CONF_BACKUP"
        exit $?
fi

if [ -n "$CONF_RESTORE" ]; then
        if [ "$CONF_RESTORE" != "-" ] && [ ! -f "$CONF_RESTORE" ]; then
                echo "Backup archive ‘$CONF_RESTORE‘ not found."
                exit 1
        fi

        [ "$VERBOSE" -gt 1 ] && TAR_V="v" || TAR_V=""
        tar -C / -x${TAR_V}zf "$CONF_RESTORE"
        exit $?
fi

type platform_check_image >/dev/null 2>/dev/null || {
        echo "Firmware upgrade is not implemented for this platform."
        exit 1
}

for check in $sysupgrade_image_check; do
        ( eval "$check \"\$ARGV\"" ) || {
                if [ $FORCE -eq 1 ]; then
                        echo "Image check ‘$check‘ failed but --force given - will update anyway!"
                        break
                else
                        echo "Image check ‘$check‘ failed."
                        exit 1
                fi
        }
done

if [ -n "$CONF_IMAGE" ]; then
        case "$(get_magic_word $CONF_IMAGE cat)" in
                # .gz files
                1f8b) ;;
                *)
                        echo "Invalid config file. Please use only .tar.gz files"
                        exit 1
                ;;
        esac
        get_image "$CONF_IMAGE" "cat" > "$CONF_TAR"
        export SAVE_CONFIG=1
elif ask_bool $SAVE_CONFIG "Keep config files over reflash"; then
        [ $TEST -eq 1 ] || do_save_conffiles
        export SAVE_CONFIG=1
else
        export SAVE_CONFIG=0
fi

if [ $TEST -eq 1 ]; then
        exit 0
fi

run_hooks "" $sysupgrade_pre_upgrade

# Some platforms/devices may want different sysupgrade process, e.g. without
# killing processes yet or calling ubus system upgrade method.
# This is needed e.g. on NAND devices where we just want to trigger stage1 at
# this point.
if type ‘platform_pre_upgrade‘ >/dev/null 2>/dev/null; then
        platform_pre_upgrade "$ARGV"
fi

ubus call system upgrade
touch /tmp/sysupgrade

if [ ! -f /tmp/failsafe ] ; then
        kill_remaining TERM
        sleep 3
        kill_remaining KILL
fi

if [ -n "$(rootfs_type)" ]; then
        v "Switching to ramdisk..."
        run_ramfs ‘. /lib/functions.sh; include /lib/upgrade; do_upgrade‘
else
        do_upgrade
fi