新增ubuntu版 於文末
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作者: czm (czm) 看板: Linux
標題: Re: [心得] 閒聊+雙系統另種選擇 loopdevice
時間: Fri Jul 21 07:57:04 2017

已經成功像一般的distro 可以從 iso file boot 了

其中第2部份必須改寫
又將共同的功能寫成function 放在最前面 成為第0部份
而第1部份參數有重新命名

從 iso file boot 是目前最複雜的使用情況
主要動作有 1. 掛載iso
           2. 掛載iso 裡面的loopfile 到 lower
           3. 掛載另一個可寫的device ( tmpfs, loopfile 或 block device), 給 upper 和 work
           4. mount 好整個 OverlayFS 然後boot.
完全參數化 會有10多個參數 如此才夠應付多數情況

以下為 initrd.d/linuxrc的新增4部份
=====================================
# zm 0

# $1: device name
# $2: mount point (full path)
# $3: caller's var for storing the results
is_mounted() {
        local _FOUND
        eval _FOUND='$( [ -n "$( mount | grep "${1} on ${2} " )" ] && echo '1' || echo '0' )'
        if [ -n "${3}" ]; then
                eval $"${3}"='"$_FOUND"'
        else
                echo "$_FOUND" # > /dev/null
        fi
}

# $1: device name
# $2: mount point
# $3: options
mount_device() {
        if [ -e "${1}" -a -d "${2}" ] && [ "$( is_mounted "${1}" "${2}" )" -eq '0' ]; then
                if [ -n "${3}" ]; then
                        echo mount -o "${3}" "${1}" "${2}"
                        mount -o "${3}" "${1}" "${2}"
                else
                        echo mount "${1}" "${2}"
                        mount "${1}" "${2}"
                fi
        fi
}

# $1: file name
# $2: mount point
# $3: options
mount_loopfile() {
        if [ -f "${1}" -a -d "${2}" ]; then
                local DEV=$( losetup -f )               # local DEV=`losetup -f`
                echo losetup "$DEV" "${1}"
                losetup "$DEV" "${1}"
                if [ -n "${3}" ]; then
                        echo mount -o "${3}" "$DEV" "${2}"
                        mount -o "${3}" "$DEV" "${2}"
                else
                        echo mount "$DEV" "${2}"
                        mount "$DEV" "${2}"
                fi
        fi
}

# $1: name
real_device() {
        local DEVICE="${1}"
        case "${DEVICE}" in
                UUID\=*|LABEL\=*)
                        local REAL_DEVICE=""
                        local retval=1

                        if [ "${retval}" -ne 0 ]; then
                                REAL_DEVICE=$( findfs "${DEVICE}" 2>/dev/null)
                                retval=$?
                        fi

                        if [ "$retval" -ne 0 ]; then
                                REAL_DEVICE=$( busybox findfs "${DEVICE}" 2>/dev/null)
                                retval=$?
                        fi

                        if [ "${retval}" -ne 0 ]; then
                                REAL_DEVICE=$( blkid -o device -l -t "${DEVICE}")
                                retval=$?
                        fi

                        if [ "${retval}" -eq 0 ] && [ -n "${REAL_DEVICE}" ]; then
                                DEVICE="${REAL_DEVICE}"
                        fi
                ;;
        esac
        echo -n "${DEVICE}"
}

# $1: dev name
# $2: mount point
# $3: loopfile
# $4: loopfile mount point
# $5: loopfile mount options
setup_loop_device() {
        REAL_LOOPS_DEV=$( real_device "${1}" )
#       echo mount_device "$REAL_LOOPS_DEV" "${2}"
        mount_device "$REAL_LOOPS_DEV" "${2}"
        local DEV=$( losetup -f)                # local DEV=`losetup -f`
        if [ -e "${3}" ]; then
                echo losetup "$DEV" "${3}"
                losetup "$DEV" "${3}"
                if [ -n "${4}" ]; then
                        mkdir -p "${4}"
#                       echo mount_device  "$DEV" "${4}" "${5}"
                        mount_device  "$DEV" "${4}" "${5}"
                fi
        fi
}

# $1: lower dir
# $2: upper dir
# $3: work dir
# $4: merged dir
setup_overlay_fs() {
        mount -t overlay -o lowerdir="${1}",upperdir="${2}",workdir="${3}" overlay "${4}"
}
# zm

======================================

                # zm 1: get parameters for boot from loop file or overlayfs
                loops_dev=*)
                        LOOPS_DEV=${x#*=}
                ;;
                loops_dev_mnt=*)
                        LOOPS_DEV_MNT=${x#*=}
                ;;
                loop_file=*)
                        LOOP_FILE=${x#*=}
                ;;
                loop_file_mnt=*)
                        LOOP_FILE_MNT=${x#*=}
                ;;
                loop_file_mnt_opt=*)
                        LOOP_FILE_MNT_OPT=${x#*=}
                ;;
                ovl_dev0=*)
                        OVL_DEV0=${x#*=}
                ;;
                ovl_mnt0=*)
                        OVL_MNT0=${x#*=}
                ;;
                ovl_loopfile0=*)
                        OVL_LOOPFILE0=${x#*=}
                ;;
                ovl_mnt0_sub=*)
                        OVL_MNT0_SUB=${x#*=}
                ;;
                ovl_dev1=*)
                        OVL_DEV1=${x#*=}
                ;;
                ovl_mnt1=*)
                        OVL_MNT1=${x#*=}
                ;;
                ovl_mnt1_opt=*)
                        OVL_MNT1_OPT=${x#*=}
                ;;
                ovl_loopfile1=*)
                        OVL_LOOPFILE1=${x#*=}
                ;;
                ovl_mnt1_sub=*)
                        OVL_MNT1_SUB=${x#*=}
                ;;
                mount_move)
                        MOUNT_MOVE=1
                ;; # zm
================================================
# zm 2: find the device which contains loop files, mount and losetup.
if [ -n "${LOOPS_DEV}" ]; then
        if [ -z "${LOOPS_DEV_MNT}" ]; then
                LOOPS_DEV_MNT='/loops'
        fi
        mkdir -p $LOOPS_DEV_MNT
        good_msg setup_loop_device "${LOOPS_DEV}" "${LOOPS_DEV_MNT}" "${LOOP_FILE}" "${LOOP_FILE_MNT}" "${LOOP_FILE_MNT_OPT}"
        setup_loop_device "${LOOPS_DEV}" "${LOOPS_DEV_MNT}" "${LOOP_FILE}" "${LOOP_FILE_MNT}" "${LOOP_FILE_MNT_OPT}"
fi
# zm 2-1: find the devices, loopfiles, dirs for overlay fs.
if [ "${ROOTFSTYPE}" = 'overlay' ]; then
        OVL_MNT_DEV0=""
        if [ -n  "${OVL_DEV0}" ]; then
                OVL_MNT_DEV0=$( real_device "${OVL_DEV0}" )
        fi
        if [ -n "${OVL_MNT_DEV0}" ] && [ -n "${OVL_MNT0}" ]; then
                mkdir -p ${OVL_MNT0}
                good_msg mount_device
                echo "${OVL_MNT_DEV0}"  "${OVL_MNT0}"
                mount_device "${OVL_MNT_DEV0}"  "${OVL_MNT0}"
                if [ "$?" = '0' ]; then
                        OVL_DEV0_MOUNTED=1
                else
                        OVL_DEV0_MOUNTED=0
                fi
        fi
    if [ "${OVL_DEV0_MOUNTED}" = '1' ]; then
        if [ -n "${OVL_LOOPFILE0}" ]; then
            if [ -z "${OVL_MNT0_SUB}" ]; then
                OVL_MNT0_SUB="/lower"
            fi
            mkdir -p "${OVL_MNT0_SUB}"
            good_msg mount_loopfile
            echo "${OVL_LOOPFILE0}" "${OVL_MNT0_SUB}"
            mount_loopfile "${OVL_LOOPFILE0}" "${OVL_MNT0_SUB}"
            LOWER="${OVL_MNT0_SUB}"
        else
            if [ -n "${OVL_MNT0_SUB}" ]; then
                LOWER="${OVL_MNT0_SUB}"
            else
                LOWER="${OVL_MNT0}"
            fi
        fi
    fi
    if [ -n "${OVL_DEV1}" ]; then
     if [ "${OVL_DEV1}" = 'tmpfs' ]; then
            if [ -z "${OVL_MNT1_OPT}" ]; then
                OVL_MNT1_OPT='size=3072m'
            fi
            mkdir -p "${OVL_MNT1}"
            good_msg "mount -t tmpfs -o ${OVL_MNT1_OPT} ${OVL_DEV1} ${OVL_MNT1}"
            mount -t tmpfs -o "${OVL_MNT1_OPT}" "${OVL_DEV1}" "${OVL_MNT1}"
            UPPER="${OVL_MNT1}/upper"
            mkdir -p "${OVL_MNT1}/upper"
            WORK="${OVL_MNT1}/work"
            mkdir -p "${OVL_MNT1}/work"
     else       # [ "${OVL_DEV1}" = 'tmpfs' ]
        OVL_MNT_DEV1=""
        if [ -n  "${OVL_DEV1}" ]; then
                OVL_MNT_DEV1=$( real_device "${OVL_DEV1}" )
        fi
        if [ -n "${OVL_MNT_DEV1}" ] && [ -n "${OVL_MNT1}" ]; then
            mkdir -p ${OVL_MNT1}
            echo mount ${OVL_MNT_DEV1}  ${OVL_MNT1}
            mount ${OVL_MNT_DEV1}  ${OVL_MNT1}
            if [ -z "${OVL_LOOPFILE1}" ]; then
                UPPER="${OVL_MNT1}/upper"
                mkdir -p "${OVL_MNT1}/upper"
                WORK="${OVL_MNT1}/work"
                mkdir -p "${OVL_MNT1}/work"
            fi
        fi
        if [ -n "${OVL_LOOPFILE1}" ]; then
            if [ -z "${OVL_MNT1_SUB}" ]; then
                OVL_MNT1_SUB="${OVL_MNT1}/rw"
            fi
            mkdir -p "${OVL_MNT1_SUB}"
            good_msg mount_loopfile
            echo "${OVL_LOOPFILE1}" "${OVL_MNT1_SUB}"
            mount_loopfile "${OVL_LOOPFILE1}" "${OVL_MNT1_SUB}"
            mkdir -p "${OVL_MNT1_SUB}/upper"
            mkdir -p "${OVL_MNT1_SUB}/work"
            UPPER="${OVL_MNT1_SUB}/upper"
            WORK="${OVL_MNT1_SUB}/work"
        else
            if [ -n "${OVL_MNT1_SUB}" ]; then
                    mkdir -p "${OVL_MNT1_SUB}/upper"
                    mkdir -p "${OVL_MNT1_SUB}/work"
                    UPPER="${OVL_MNT1_SUB}/upper"
                    WORK="${OVL_MNT1_SUB}/work"
            fi
        fi
     fi # [ "${OVL_DEV1}" = 'tmpfs' ]
    else # [ -n "${OVL_DEV1}" ]
        if [ -n "${OVL_LOOPFILE1}" ]; then
            if [ -z "${OVL_MNT1_SUB}" ]; then
                OVL_MNT1_SUB="${OVL_MNT0}/rw"
            fi
            mkdir -p "${OVL_MNT1_SUB}"
            good_msg mount_loopfile
            echo "${OVL_LOOPFILE1}" "${OVL_MNT1_SUB}"
            mount_loopfile "${OVL_LOOPFILE1}" "${OVL_MNT1_SUB}"
            mkdir -p "${OVL_MNT1_SUB}/upper"
            mkdir -p "${OVL_MNT1_SUB}/work"
            UPPER="${OVL_MNT1_SUB}/upper"
            WORK="${OVL_MNT1_SUB}/work"
        else    #[ -n "${OVL_LOOPFILE1}" ]
            if [ -n "${OVL_MNT1_SUB}" ]; then
                    mkdir -p "${OVL_MNT1_SUB}/upper"
                    mkdir -p "${OVL_MNT1_SUB}/work"
                    UPPER="${OVL_MNT1_SUB}/upper"
                    WORK="${OVL_MNT1_SUB}/work"
            else
                if [ -z "${UPPER}" ]; then
                        UPPER="${OVL_MNT0}/upper"
                        mkdir -p "${OVL_MNT0}/upper"
                fi
                if [ -z "${WORK}" ]; then
                        WORK="${OVL_MNT0}/work"
                        mkdir -p "${OVL_MNT0}/work"
                fi
            fi  #[ -n "${OVL_MNT1_SUB}" ]
        fi      #[ -n "${OVL_LOOPFILE1}" ]
    fi # [ -n "${OVL_DEV1}" ]
    good_msg "OverlayFS: lowerdir=${LOWER},upperdir=${UPPER},workdir=${WORK} ..."
    REAL_ROOTFLAGS="lowerdir=${LOWER},upperdir=${UPPER},workdir=${WORK}"
    got_good_root=1
fi # zm [ "${ROOTFSTYPE}" = 'overlay' ]
=========================================================
# zm 3: move LOOPS_DEV_MNT or OVL_MNTs from initramfs to real root
if [ "${MOUNT_MOVE}" = '1' ]; then
        if [ -n "${LOOPS_DEV_MNT}" ]; then
                if [ ! -e "${CHROOT}${LOOPS_DEV_MNT}" ]; then
                        mkdir -p "${CHROOT}${LOOPS_DEV_MNT}"
                fi
                good_msg "Remounting device=${LOOPS_DEV} to ${CHROOT}${LOOPS_DEV_MNT}"
                mount --move "${LOOPS_DEV_MNT}" "${CHROOT}${LOOPS_DEV_MNT}"
        fi
        if [ -n "${OVL_MNT0}" ]; then
                if [ ! -e "${CHROOT}${OVL_MNT0}" ]; then
                        mkdir -p "${CHROOT}${OVL_MNT0}"
                fi
                good_msg "Remounting device=${OVL_DEV0} to ${CHROOT}${OVL_MNT0}"
                mount --move "${OVL_MNT0}" "${CHROOT}${OVL_MNT0}"
        fi
        if [ -n "${OVL_MNT1}" ]; then
                if [ ! -e "${CHROOT}${OVL_MNT1}" ]; then
                        mkdir -p "${CHROOT}${OVL_MNT1}"
                fi
        good_msg "Remounting device=${OVL_DEV1} to ${CHROOT}${OVL_MNT1}"
        mount --move "${OVL_MNT1}" "${CHROOT}${OVL_MNT1}"
        fi
fi # zm
=========================================

--
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※ 文章網址: https://www.ptt.cc/bbs/Linux/M.1500595026.A.51D.html

ubuntu版 把共用部份放在 /etc/initramfs-tools/scripts/ 下
           mount部份放在 /etc/initramfs-tools/scripts/init-premount/ 下
           mount_move部份放在 /etc/initramfs-tools/scripts/init-bottom/ 下
          （引用共用部份要記得先source）
然後執行  update-initramfs -c -k $(uname -r) 就可以得到新版的initrd了


※ 編輯: czm (1.163.162.22), 08/14/2017 10:36:06