openwrt: sysupgrade

sysupgrade

用法:

sysupgrade [<升级选项>...] <image file 或 URL>
sysupgrade [-q] [-i] <备份选项>

升级选项:

  • -d 重启前等待 delay 秒
  • -f 从 .tar.gz (文件或链接) 中恢复配置文件
  • -i 交互模式
  • -c 保留 /etc 中所有修改过的文件
  • -n 重刷固件时不保留配置文件
  • -T | --test 校验固件 config .tar.gz,但不真正烧写
  • -F | --force 即使固件校验失败也强制烧写
  • -q 较少的输出信息
  • -v 详细的输出信息
  • -h 显示帮助信息

备份选项:

  • -b | --create-backup
    把sysupgrade.conf 里描述的文件打包成.tar.gz 作为备份,不做烧写动作
  • -r | --restore-backup
    从-b 命令创建的 .tar.gz 文件里恢复配置,不做烧写动作
  • -l | --list-backup
    列出 -b 命令将备份的文件列表,但不创建备份文件

举例

  • 更新openwrt.bin固件
    sysupgrade openwrt.bin

  • 强制更新openwrt.bin固件
    sysupgrade会检查支持板子的固件头信息,如果一个model没有在sysupgrade的支持列表里,使用-F来忽略检查失败,强制烧写。
    sysupgrade -F openwrt.bin

  • 更新后不保存之前的配置
    sysupgrade烧写时默认会备份配置文件,在烧写后把配置文件覆盖到新系统中。-n参数指定不做这个动作。
    sysupgrade -n openwrt.bin

  • 备份配置文件到/tmp/backup.tgz
    sysupgrade -b /tmp/backup.tgz

  • 恢复之前备份的/tmp/backup.tgz
    sysupgrade -r /tmp/backup.tgz

  • 列出会被备份的文件
    sysupgrade -l
    列出的文件会在-b备份时或系统升级时被保存。

实现

解析选项参数

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

解析选项。\(ARGV是参数列表,\)ARGC是参数个数。
选项中有-d, -b, -r, -f时,由于这些选项都要带一个参数,所以使用了shift去减少\(ARGV和\)ARGC的值。

CONFFILES 和 CONF_TAR 是两个临时文件,后面会用到。

sysupgrade openwrt.bin --> ARGV="openwrt.bin", ARGC=1
sysupgrade -b config.backup --> ARGV为空,ARGC=0

判断参数合法

[ -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
}

如果sysupgrade附带参数-b或-r时,则$NEED_IMAGE=1,否则为空
$NEED_IMAGE=1时,我们希望ARGV是空的,否则就是出错,则输出帮助信息,并退出。
例如:

  • sysupgrade -b config.backup,此时$NEED_IMAGE=1, ARGV为空,合法
  • sysupgrade -b config.backup openwrt.bin,此时$NEED_IMAGE=1, ARGV为"openwrt.bin",参数多了,错误。
# 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"

带-c参数,且"/overlay/etc"目录存在 --> sysupgrade_init_conffiles="add_overlayfiles"
否则 --> sysupgrade_init_conffiles="add_uci_conffiles"

这里会影响要备份的配置文件

include /lib/upgrade

包含lib/upgrade目录下的所有文件

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

命令指定nand时,则调用nand_upgrade_stage2函数,例如sysupgrade nand openwrt.bin。 暂时使用spi flash,不讨论这里。

backup list

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 2>/dev/null;
	  opkg list-changed-conffiles ) | sort -u > "$file"
	return 0
}

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

列出一份文件列表,放入/tmp/sysupgrade.conffiles,打印出来,然后删掉。文件列表:

find $(sed -ne '/^[[:space:]]*$/d; /^#/d; p' /etc/sysupgrade.conf /lib/upgrade/keep.d/* 2>/dev/null) -type f 2>/dev/null

opkg list-changed-conffiles

create backup

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

-b 如果指定打包文件时,$CONF_BACKUP 为那个文件名。则此时按如下流程来生成备份文件:

do_save_conffiles
  -> sysupgrade_init_conffiles
     -> add_uci_conffiles
        -> tar czf /tmp/backup.tgz -T /tmp/sysupgrade.conffiles
	-> rm -f /tmp/sysupgrade.conffiles

restore

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

sysupgrade -r config.tgz --> tar -C / -xzf config.tgz
解压,覆盖到/目录下

image check

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

sysupgrade openwrt.bin --> 检查bin文件:platform_check_image openwrt.bin
lib/upgrade/platform.sh 中定义platform_check_image函数,取.bin文件的头部,检查magic number

upgrade backup

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

在升级时会先保存配置文件到/tmp/sysupgrade.tgz

  1. -f 指定配置文件
  2. 交互模式 ask_bool 可以获取输入值,如果不在交互模式,则ask_bool的第一个参数就是默认值。
    $SAVE_CONFIG默认为1, 这里调用do_save_conffiles保存当前系统的配置文件。

upgrade

if [ -n "$(rootfs_type)" ]; then
	v "Switching to ramdisk..."
	run_ramfs '. /lib/functions.sh; include /lib/upgrade; do_upgrade'
else
	do_upgrade
fi
  1. rootfs_type = "overlayfs" ,执行第一个逻辑
  2. run_ramfs, 在/tmp/root下安装一个临时ramdisk,最后再执行do_upgrade
  3. do_upgrade -> platform_do_upgrade -> get_image "$1" | mtd -j "$CONF_TAR" write - "firmware"

mtd工具在写入时,会把$CONF_TAR文件整合进入jffs2分区,可以看到打印信息:

Appending jffs2 data from /tmp/sysupgrade.tgz to firmware...

Sysupgrade – Technical Reference

posted @ 2014-09-15 17:59  sammei  阅读(13291)  评论(0编辑  收藏  举报