dracut-functions.sh: get_fs_env() replaced egrep with shell

[thirdparty/dracut.git] / dracut-functions.sh

#!/bin/bash
# -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
# ex: ts=8 sw=4 sts=4 et filetype=sh
#
# functions used by dracut and other tools.
#
# Copyright 2005-2009 Red Hat, Inc.  All rights reserved.
#
# 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 2 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/>.
#

if ! [[ $dracutbasedir ]]; then
    dracutbasedir=${BASH_SOURCE[0]%/*}
    [[ $dracutbasedir = "dracut-functions" ]] && dracutbasedir="."
    [[ $dracutbasedir ]] || dracutbasedir="."
    dracutbasedir="$(readlink -f $dracutbasedir)"
fi

if ! type dinfo >/dev/null 2>&1; then
    . "$dracutbasedir/dracut-logger.sh"
    dlog_init
fi

# export standard hookdirs
[[ $hookdirs ]] || {
    hookdirs="cmdline pre-udev pre-trigger netroot initqueue pre-mount"
    hookdirs+=" pre-pivot mount emergency shutdown-emergency shutdown cleanup"
    export hookdirs
}

# Generic substring function.  If $2 is in $1, return 0.
strstr() { [ "${1#*$2*}" != "$1" ]; }

# Create all subdirectories for given path without creating the last element.
# $1 = path
mksubdirs() { mkdir -m 0755 -p ${1%/*}; }

# Version comparision function.  Assumes Linux style version scheme.
# $1 = version a
# $2 = comparision op (gt, ge, eq, le, lt, ne)
# $3 = version b
vercmp() {
    local _n1=(${1//./ }) _op=$2 _n2=(${3//./ }) _i _res

    for ((_i=0; ; _i++))
    do
        if [[ ! ${_n1[_i]}${_n2[_i]} ]]; then _res=0
        elif ((${_n1[_i]:-0} > ${_n2[_i]:-0})); then _res=1
        elif ((${_n1[_i]:-0} < ${_n2[_i]:-0})); then _res=2
        else continue
        fi
        break
    done

    case $_op in
        gt) ((_res == 1));;
        ge) ((_res != 2));;
        eq) ((_res == 0));;
        le) ((_res != 1));;
        lt) ((_res == 2));;
        ne) ((_res != 0));;
    esac
}

# is_func <command>
# Check whether $1 is a function.
is_func() {
    [[ $(type -t $1) = "function" ]]
}

# Function prints global variables in format name=value line by line.
# $@ = list of global variables' name
print_vars() {
    local _var _value

    for _var in $@
    do
        _value=$(eval echo \$$_var)
        [[ ${_value} ]] && echo "${_var}=\"${_value}\""
    done
}

# normalize_path <path>
# Prints the normalized path, where it removes any duplicated
# and trailing slashes.
# Example:
# $ normalize_path ///test/test//
# /test/test
normalize_path() {
    shopt -q -s extglob
    set -- "${1//+(\/)//}"
    shopt -q -u extglob
    echo "${1%/}"
}

# convert_abs_rel <from> <to>
# Prints the relative path, when creating a symlink to <to> from <from>.
# Example:
# $ convert_abs_rel /usr/bin/test /bin/test-2
# ../../bin/test-2
# $ ln -s $(convert_abs_rel /usr/bin/test /bin/test-2) /usr/bin/test
convert_abs_rel() {
    local __current __absolute __abssize __cursize __newpath
    local -i __i __level

    set -- "$(normalize_path "$1")" "$(normalize_path "$2")"

    # corner case #1 - self looping link
    [[ "$1" == "$2" ]] && { echo "${1##*/}"; return; }

    # corner case #2 - own dir link
    [[ "${1%/*}" == "$2" ]] && { echo "."; return; }

    IFS="/" __current=($1)
    IFS="/" __absolute=($2)

    __abssize=${#__absolute[@]}
    __cursize=${#__current[@]}

    while [[ ${__absolute[__level]} == ${__current[__level]} ]]
    do
        (( __level++ ))
        if (( __level > __abssize || __level > __cursize ))
        then
            break
        fi
    done

    for ((__i = __level; __i < __cursize-1; __i++))
    do
        if ((__i > __level))
        then
            __newpath=$__newpath"/"
        fi
        __newpath=$__newpath".."
    done

    for ((__i = __level; __i < __abssize; __i++))
    do
        if [[ -n $__newpath ]]
        then
            __newpath=$__newpath"/"
        fi
        __newpath=$__newpath${__absolute[__i]}
    done

    echo "$__newpath"
}

# get_fs_env <device>
# Get and set the ID_FS_TYPE and ID_FS_UUID variable from udev for a device.
# Example:
# $ get_fs_env /dev/sda2; echo $ID_FS_TYPE; echo $ID_FS_UUID
# ext4
# 551a39aa-4ae9-4e70-a262-ef665cadb574
get_fs_env() {
    [[ $1 ]] || return
    unset ID_FS_TYPE
    unset ID_FS_UUID
    eval $(udevadm info --query=env --name=$1 \
        | while read line; do
            [[ "$line" =~ 'ID_FS_(TYPE|UUID)=' ]] && echo $line;
            done)
    [[ $ID_FS_TYPE ]] && return

    if [[ -x /lib/udev/vol_id ]]; then
        eval $(/lib/udev/vol_id --export $1)
    elif find_binary blkid >/dev/null; then
        eval $(blkid -o udev $1)
    else
        return 1
    fi
}

# get_fs_uuid <device>
# Prints the filesystem UUID for a device.
# Example:
# $ get_fs_uuid /dev/sda2
# 551a39aa-4ae9-4e70-a262-ef665cadb574
get_fs_uuid() (
    get_fs_env $1 || return
    echo $ID_FS_UUID
)

# get_fs_type <device>
# Prints the filesystem type for a device.
# Example:
# $ get_fs_type /dev/sda1
# ext4
get_fs_type() (
    [[ $1 ]] || return
    if [[ $1 != ${1#/dev/block/nfs:} ]] \
        || [[ $1 != ${1#/dev/block/nfs3:} ]] \
        || [[ $1 != ${1#/dev/block/nfs4:} ]]; then
        echo "nfs"
        return
    fi
    if get_fs_env $1; then
        echo $ID_FS_TYPE
        return
    fi
    find_dev_fstype $1
)

# get_maj_min <device>
# Prints the major and minor of a device node.
# Example:
# $ get_maj_min /dev/sda2
# 8:2
get_maj_min() {
    local _dev
    _dev=$(stat -L -c '$((0x%t)):$((0x%T))' "$1" 2>/dev/null)
    _dev=$(eval "echo $_dev")
    echo $_dev
}

# find_block_device <mountpoint>
# Prints the major and minor number of the block device
# for a given mountpoint.
# Unless $use_fstab is set to "yes" the functions
# uses /proc/self/mountinfo as the primary source of the
# information and only falls back to /etc/fstab, if the mountpoint
# is not found there.
# Example:
# $ find_block_device /usr
# 8:4
find_block_device() {
    local _x _mpt _majmin _dev _fs _maj _min
    if [[ $use_fstab != yes ]]; then
        while read _x _x _majmin _x _mpt _x _x _fs _dev _x; do
            [[ $_mpt = $1 ]] || continue
            [[ $_fs = nfs ]] && { echo $_dev; return 0;}
            [[ $_fs = nfs3 ]] && { echo $_dev; return 0;}
            [[ $_fs = nfs4 ]] && { echo $_dev; return 0;}
            [[ $_fs = btrfs ]] && {
                get_maj_min $_dev
                return 0;
            }
            if [[ ${_majmin#0:} = $_majmin ]]; then
                echo $_majmin
                return 0 # we have a winner!
            fi
        done < /proc/self/mountinfo
    fi
    # fall back to /etc/fstab
    while read _dev _mpt _fs _x; do
        if [[ $_mpt = $1 ]]; then
            [[ $_fs = nfs ]] && { echo $_dev; return 0;}
            [[ $_fs = nfs3 ]] && { echo $_dev; return 0;}
            [[ $_fs = nfs4 ]] && { echo $_dev; return 0;}
            [[ $_dev != ${_dev#UUID=} ]] && _dev=/dev/disk/by-uuid/${_dev#UUID=}
            [[ $_dev != ${_dev#LABEL=} ]] && _dev=/dev/disk/by-label/${_dev#LABEL=}
            [[ -b $_dev ]] || return 1 # oops, not a block device.
            get_maj_min "$_dev" && return 0
        fi
    done < /etc/fstab

    return 1
}

# find_dev_fstype <device>
# Echo the filesystem type for a given device.
# /proc/self/mountinfo is taken as the primary source of information
# and /etc/fstab is used as a fallback.
# No newline is appended!
# Example:
# $ find_dev_fstype /dev/sda2;echo
# ext4
find_dev_fstype() {
    local _x _mpt _majmin _dev _fs _maj _min
    while read _x _x _majmin _x _mpt _x _x _fs _dev _x; do
        [[ $_dev = $1 ]] || continue
        echo -n $_fs;
        return 0;
    done < /proc/self/mountinfo

    # fall back to /etc/fstab
    while read _dev _mpt _fs _x; do
        [[ $_dev = $1 ]] || continue
        echo -n $_fs;
        return 0;
    done < /etc/fstab

    return 1
}

# finds the major:minor of the block device backing the root filesystem.
find_root_block_device() { find_block_device /; }

# for_each_host_dev_fs <func>
# Execute "<func> <dev> <filesystem>" for every "<dev>|<fs>" pair found
# in ${host_fs_types[@]}
for_each_host_dev_fs()
{
    local _func="$1"
    local _dev
    local _fs
    local _ret=1
    for f in ${host_fs_types[@]}; do
        OLDIFS="$IFS"
        IFS="|"
        set -- $f
        IFS="$OLDIFS"
        _dev="$1"
        [[ -b "$_dev" ]] || continue
        _fs="$2"
        $_func $_dev $_fs && _ret=0
    done
    return $_ret
}

# Walk all the slave relationships for a given block device.
# Stop when our helper function returns success
# $1 = function to call on every found block device
# $2 = block device in major:minor format
check_block_and_slaves() {
    local _x
    [[ -b /dev/block/$2 ]] || return 1 # Not a block device? So sorry.
    "$1" $2 && return
    check_vol_slaves "$@" && return 0
    if [[ -f /sys/dev/block/$2/../dev ]]; then
        check_block_and_slaves $1 $(cat "/sys/dev/block/$2/../dev") && return 0
    fi
    [[ -d /sys/dev/block/$2/slaves ]] || return 1
    for _x in /sys/dev/block/$2/slaves/*/dev; do
        [[ -f $_x ]] || continue
        check_block_and_slaves $1 $(cat "$_x") && return 0
    done
    return 1
}

# ugly workaround for the lvm design
# There is no volume group device,
# so, there are no slave devices for volume groups.
# Logical volumes only have the slave devices they really live on,
# but you cannot create the logical volume without the volume group.
# And the volume group might be bigger than the devices the LV needs.
check_vol_slaves() {
    local _lv _vg _pv
    for i in /dev/mapper/*; do
        _lv=$(get_maj_min $i)
        if [[ $_lv = $2 ]]; then
            _vg=$(lvm lvs --noheadings -o vg_name $i 2>/dev/null)
            # strip space
            _vg=$(echo $_vg)
            if [[ $_vg ]]; then
                for _pv in $(lvm vgs --noheadings -o pv_name "$_vg" 2>/dev/null)
                do
                    check_block_and_slaves $1 $(get_maj_min $_pv) && return 0
                done
            fi
        fi
    done
    return 1
}

# Install a directory, keeping symlinks as on the original system.
# Example: if /lib points to /lib64 on the host, "inst_dir /lib/file"
# will create ${initdir}/lib64, ${initdir}/lib64/file,
# and a symlink ${initdir}/lib -> lib64.
inst_dir() {
    [[ -e ${initdir}/"$1" ]] && return 0  # already there

    local _dir="$1" _part="${1%/*}" _file
    while [[ "$_part" != "${_part%/*}" ]] && ! [[ -e "${initdir}/${_part}" ]]; do
        _dir="$_part $_dir"
        _part=${_part%/*}
    done

    # iterate over parent directories
    for _file in $_dir; do
        [[ -e "${initdir}/$_file" ]] && continue
        if [[ -L $_file ]]; then
            inst_symlink "$_file"
        else
            # create directory
            mkdir -m 0755 -p "${initdir}/$_file" || return 1
            [[ -e "$_file" ]] && chmod --reference="$_file" "${initdir}/$_file"
            chmod u+w "${initdir}/$_file"
        fi
    done
}

# $1 = file to copy to ramdisk
# $2 (optional) Name for the file on the ramdisk
# Location of the image dir is assumed to be $initdir
# We never overwrite the target if it exists.
inst_simple() {
    [[ -f "$1" ]] || return 1
    strstr "$1" "/" || return 1

    local _src=$1 target="${2:-$1}"
    if ! [[ -d ${initdir}/$target ]]; then
        [[ -e ${initdir}/$target ]] && return 0
        [[ -L ${initdir}/$target ]] && return 0
        [[ -d "${initdir}/${target%/*}" ]] || inst_dir "${target%/*}"
    fi
    # install checksum files also
    if [[ -e "${_src%/*}/.${_src##*/}.hmac" ]]; then
        inst "${_src%/*}/.${_src##*/}.hmac" "${target%/*}/.${target##*/}.hmac"
    fi
    ddebug "Installing $_src"
    cp --sparse=always -pfL "$_src" "${initdir}/$target"
}

# find symlinks linked to given library file
# $1 = library file
# Function searches for symlinks by stripping version numbers appended to
# library filename, checks if it points to the same target and finally
# prints the list of symlinks to stdout.
#
# Example:
# rev_lib_symlinks libfoo.so.8.1
# output: libfoo.so.8 libfoo.so
# (Only if libfoo.so.8 and libfoo.so exists on host system.)
rev_lib_symlinks() {
    [[ ! $1 ]] && return 0

    local fn="$1" orig="$(readlink -f "$1")" links=''

    [[ ${fn} =~ .*\.so\..* ]] || return 1

    until [[ ${fn##*.} == so ]]; do
        fn="${fn%.*}"
        [[ -L ${fn} && $(readlink -f "${fn}") == ${orig} ]] && links+=" ${fn}"
    done

    echo "${links}"
}

# Same as above, but specialized to handle dynamic libraries.
# It handles making symlinks according to how the original library
# is referenced.
inst_library() {
    local _src="$1" _dest=${2:-$1} _lib _reallib _symlink
    strstr "$1" "/" || return 1
    [[ -e $initdir/$_dest ]] && return 0
    if [[ -L $_src ]]; then
        # install checksum files also
        if [[ -e "${_src%/*}/.${_src##*/}.hmac" ]]; then
            inst "${_src%/*}/.${_src##*/}.hmac" "${_dest%/*}/.${_dest##*/}.hmac"
        fi
        _reallib=$(readlink -f "$_src")
        inst_simple "$_reallib" "$_reallib"
        inst_dir "${_dest%/*}"
        [[ -d "${_dest%/*}" ]] && _dest=$(readlink -f "${_dest%/*}")/${_dest##*/}
        ln -sfn $(convert_abs_rel "${_dest}" "${_reallib}") "${initdir}/${_dest}"
    else
        inst_simple "$_src" "$_dest"
    fi

    # Create additional symlinks.  See rev_symlinks description.
    for _symlink in $(rev_lib_symlinks $_src) $(rev_lib_symlinks $_reallib); do
        [[ ! -e $initdir/$_symlink ]] && {
            ddebug "Creating extra symlink: $_symlink"
            inst_symlink $_symlink
        }
    done
}

# find a binary.  If we were not passed the full path directly,
# search in the usual places to find the binary.
find_binary() {
    if [[ -z ${1##/*} ]]; then
        if [[ -x $1 ]] || { strstr "$1" ".so" && ldd $1 &>/dev/null; };  then
            echo $1
            return 0
        fi
    fi

    type -P $1
}

# Same as above, but specialized to install binary executables.
# Install binary executable, and all shared library dependencies, if any.
inst_binary() {
    local _bin _target
    _bin=$(find_binary "$1") || return 1
    _target=${2:-$_bin}
    [[ -e $initdir/$_target ]] && return 0
    [[ -L $_bin ]] && inst_symlink $_bin $_target && return 0
    local _file _line
    local _so_regex='([^ ]*/lib[^/]*/[^ ]*\.so[^ ]*)'
    # I love bash!
    LC_ALL=C ldd "$_bin" 2>/dev/null | while read _line; do
        [[ $_line = 'not a dynamic executable' ]] && break

        if [[ $_line =~ $_so_regex ]]; then
            _file=${BASH_REMATCH[1]}
            [[ -e ${initdir}/$_file ]] && continue
            inst_library "$_file"
            continue
        fi

        if [[ $_line =~ not\ found ]]; then
            dfatal "Missing a shared library required by $_bin."
            dfatal "Run \"ldd $_bin\" to find out what it is."
            dfatal "$_line"
            dfatal "dracut cannot create an initrd."
            exit 1
        fi
    done
    inst_simple "$_bin" "$_target"
}

# same as above, except for shell scripts.
# If your shell script does not start with shebang, it is not a shell script.
inst_script() {
    local _bin
    _bin=$(find_binary "$1") || return 1
    shift
    local _line _shebang_regex
    read -r -n 80 _line <"$_bin"
    # If debug is set, clean unprintable chars to prevent messing up the term
    [[ $debug ]] && _line=$(echo -n "$_line" | tr -c -d '[:print:][:space:]')
    _shebang_regex='(#! *)(/[^ ]+).*'
    [[ $_line =~ $_shebang_regex ]] || return 1
    inst "${BASH_REMATCH[2]}" && inst_simple "$_bin" "$@"
}

# same as above, but specialized for symlinks
inst_symlink() {
    local _src=$1 _target=${2:-$1} _realsrc
    strstr "$1" "/" || return 1
    [[ -L $1 ]] || return 1
    [[ -L $initdir/$_target ]] && return 0
    _realsrc=$(readlink -f "$_src")
    if ! [[ -e $initdir/$_realsrc ]]; then
        if [[ -d $_realsrc ]]; then
            inst_dir "$_realsrc"
        else
            inst "$_realsrc"
        fi
    fi
    [[ -d ${_target%/*} ]] && _target=$(readlink -f ${_target%/*})/${_target##*/}
    ln -sfn $(convert_abs_rel "${_target}" "${_realsrc}") "$initdir/$_target"
}

# attempt to install any programs specified in a udev rule
inst_rule_programs() {
    local _prog _bin

    if grep -qE 'PROGRAM==?"[^ "]+' "$1"; then
        for _prog in $(grep -E 'PROGRAM==?"[^ "]+' "$1" | sed -r 's/.*PROGRAM==?"([^ "]+).*/\1/'); do
            if [ -x /lib/udev/$_prog ]; then
                _bin=/lib/udev/$_prog
            else
                _bin=$(find_binary "$_prog") || {
                    dinfo "Skipping program $_prog using in udev rule $(basename $1) as it cannot be found"
                    continue;
                }
            fi

            #dinfo "Installing $_bin due to it's use in the udev rule $(basename $1)"
            dracut_install "$_bin"
        done
    fi
}

# udev rules always get installed in the same place, so
# create a function to install them to make life simpler.
inst_rules() {
    local _target=/etc/udev/rules.d _rule _found

    inst_dir "/lib/udev/rules.d"
    inst_dir "$_target"
    for _rule in "$@"; do
        if [ "${rule#/}" = "$rule" ]; then
            for r in /lib/udev/rules.d /etc/udev/rules.d; do
                if [[ -f $r/$_rule ]]; then
                    _found="$r/$_rule"
                    inst_simple "$_found"
                    inst_rule_programs "$_found"
                fi
            done
        fi
        for r in '' ./ $dracutbasedir/rules.d/; do
            if [[ -f ${r}$_rule ]]; then
                _found="${r}$_rule"
                inst_simple "$_found" "$_target/${_found##*/}"
                inst_rule_programs "$_found"
            fi
        done
        [[ $_found ]] || dinfo "Skipping udev rule: $_rule"
    done
}

# general purpose installation function
# Same args as above.
inst() {
    local _x

    case $# in
        1) ;;
        2) [[ ! $initdir && -d $2 ]] && export initdir=$2
            [[ $initdir = $2 ]] && set $1;;
        3) [[ -z $initdir ]] && export initdir=$2
            set $1 $3;;
        *) dfatal "inst only takes 1 or 2 or 3 arguments"
            exit 1;;
    esac
    for _x in inst_symlink inst_script inst_binary inst_simple; do
        $_x "$@" && return 0
    done
    return 1
}

# install function specialized for hooks
# $1 = type of hook, $2 = hook priority (lower runs first), $3 = hook
# All hooks should be POSIX/SuS compliant, they will be sourced by init.
inst_hook() {
    if ! [[ -f $3 ]]; then
        dfatal "Cannot install a hook ($3) that does not exist."
        dfatal "Aborting initrd creation."
        exit 1
    elif ! strstr "$hookdirs" "$1"; then
        dfatal "No such hook type $1. Aborting initrd creation."
        exit 1
    fi
    inst_simple "$3" "/lib/dracut/hooks/${1}/${2}${3##*/}"
}

# install any of listed files
#
# If first argument is '-d' and second some destination path, first accessible
# source is installed into this path, otherwise it will installed in the same
# path as source.  If none of listed files was installed, function return 1.
# On first successful installation it returns with 0 status.
#
# Example:
#
# inst_any -d /bin/foo /bin/bar /bin/baz
#
# Lets assume that /bin/baz exists, so it will be installed as /bin/foo in
# initramfs.
inst_any() {
    local to f

    [[ $1 = '-d' ]] && to="$2" && shift 2

    for f in "$@"; do
        if [[ -e $f ]]; then
            [[ $to ]] && inst "$f" "$to" && return 0
            inst "$f" && return 0
        fi
    done

    return 1
}

# dracut_install [-o ] <file> [<file> ... ]
# Install <file> to the initramfs image
# -o optionally install the <file> and don't fail, if it is not there
dracut_install() {
    local _optional=no
    if [[ $1 = '-o' ]]; then
        _optional=yes
        shift
    fi
    while (($# > 0)); do
        if ! inst "$1" ; then
            if [[ $_optional = yes ]]; then
                dinfo "Skipping program $1 as it cannot be found and is" \
                    "flagged to be optional"
            else
                dfatal "Failed to install $1"
                exit 1
            fi
        fi
        shift
    done
}

# install function decompressing the target and handling symlinks
# $@ = list of compressed (gz or bz2) files or symlinks pointing to such files
#
# Function install targets in the same paths inside overlay but decompressed
# and without extensions (.gz, .bz2).
inst_decompress() {
    local _src _dst _realsrc _realdst _cmd

    for _src in $@
    do
        case ${_src} in
            *.gz) _cmd='gzip -d' ;;
            *.bz2) _cmd='bzip2 -d' ;;
            *) return 1 ;;
        esac

        if [[ -L ${_src} ]]
        then
            _realsrc="$(readlink -f ${_src})" # symlink target with extension
            _dst="${_src%.*}" # symlink without extension
            _realdst="${_realsrc%.*}" # symlink target without extension
            mksubdirs "${initdir}/${_src}"
            # Create symlink without extension to target without extension.
            ln -sfn "${_realdst}" "${initdir}/${_dst}"
        fi

        # If the source is symlink we operate on its target.
        [[ ${_realsrc} ]] && _src=${_realsrc}
        inst ${_src}
        # Decompress with chosen tool.  We assume that tool changes name e.g.
        # from 'name.gz' to 'name'.
        ${_cmd} "${initdir}${_src}"
    done
}

# It's similar to above, but if file is not compressed, performs standard
# install.
# $@ = list of files
inst_opt_decompress() {
    local _src

    for _src in $@
    do
        inst_decompress "${_src}" || inst "${_src}"
    done
}

# module_check <dracut module>
# execute the check() function of module-setup.sh of <dracut module>
# or the "check" script, if module-setup.sh is not found
# "check $hostonly" is called
module_check() {
    local _moddir=$(echo ${dracutbasedir}/modules.d/??${1})
    local _ret
    local _forced=0
    local _hostonly=$hostonly
    [ $# -eq 2 ] && _forced=$2
    [[ -d $_moddir ]] || return 1
    if [[ ! -f $_moddir/module-setup.sh ]]; then
        # if we do not have a check script, we are unconditionally included
        [[ -x $_moddir/check ]] || return 0
        [ $_forced -ne 0 ] && unset hostonly
        $_moddir/check $hostonly
        _ret=$?
    else
        unset check depends install installkernel
        . $_moddir/module-setup.sh
        is_func check || return 0
        [ $_forced -ne 0 ] && unset hostonly
        check $hostonly
        _ret=$?
        unset check depends install installkernel
    fi
    hostonly=$_hostonly
    return $_ret
}

# module_check_mount <dracut module>
# execute the check() function of module-setup.sh of <dracut module>
# or the "check" script, if module-setup.sh is not found
# "mount_needs=1 check 0" is called
module_check_mount() {
    local _moddir=$(echo ${dracutbasedir}/modules.d/??${1})
    local _ret
    mount_needs=1
    [[ -d $_moddir ]] || return 1
    if [[ ! -f $_moddir/module-setup.sh ]]; then
        # if we do not have a check script, we are unconditionally included
        [[ -x $_moddir/check ]] || return 0
        mount_needs=1 $_moddir/check 0
        _ret=$?
    else
        unset check depends install installkernel
        . $_moddir/module-setup.sh
        is_func check || return 1
        check 0
        _ret=$?
        unset check depends install installkernel
    fi
    unset mount_needs
    return $_ret
}

# module_depends <dracut module>
# execute the depends() function of module-setup.sh of <dracut module>
# or the "depends" script, if module-setup.sh is not found
module_depends() {
    local _moddir=$(echo ${dracutbasedir}/modules.d/??${1})
    local _ret
    [[ -d $_moddir ]] || return 1
    if [[ ! -f $_moddir/module-setup.sh ]]; then
        # if we do not have a check script, we have no deps
        [[ -x $_moddir/check ]] || return 0
        $_moddir/check -d
        return $?
    else
        unset check depends install installkernel
        . $_moddir/module-setup.sh
        is_func depends || return 0
        depends
        _ret=$?
        unset check depends install installkernel
        return $_ret
    fi
}

# module_install <dracut module>
# execute the install() function of module-setup.sh of <dracut module>
# or the "install" script, if module-setup.sh is not found
module_install() {
    local _moddir=$(echo ${dracutbasedir}/modules.d/??${1})
    local _ret
    [[ -d $_moddir ]] || return 1
    if [[ ! -f $_moddir/module-setup.sh ]]; then
        [[ -x $_moddir/install ]] && . "$_moddir/install"
        return $?
    else
        unset check depends install installkernel
        . $_moddir/module-setup.sh
        is_func install || return 0
        install
        _ret=$?
        unset check depends install installkernel
        return $_ret
    fi
}

# module_installkernel <dracut module>
# execute the installkernel() function of module-setup.sh of <dracut module>
# or the "installkernel" script, if module-setup.sh is not found
module_installkernel() {
    local _moddir=$(echo ${dracutbasedir}/modules.d/??${1})
    local _ret
    [[ -d $_moddir ]] || return 1
    if [[ ! -f $_moddir/module-setup.sh ]]; then
        [[ -x $_moddir/installkernel ]] && . "$_moddir/installkernel"
        return $?
    else
        unset check depends install installkernel
        . $_moddir/module-setup.sh
        is_func installkernel || return 0
        installkernel
        _ret=$?
        unset check depends install installkernel
        return $_ret
    fi
}

# check_mount <dracut module>
# check_mount checks, if a dracut module is needed for the given
# device and filesystem types in "${host_fs_types[@]}"
check_mount() {
    local _mod=$1
    local _moddir=$(echo ${dracutbasedir}/modules.d/??${1})
    local _ret
    local _moddep
    # If we are already scheduled to be loaded, no need to check again.
    strstr " $mods_to_load " " $_mod " && return 0
    strstr " $mods_checked_as_dep " " $_mod " && return 1

    # This should never happen, but...
    [[ -d $_moddir ]] || return 1

    [[ $2 ]] || mods_checked_as_dep+=" $_mod "

    strstr " $omit_dracutmodules " " $_mod " && return 1

    if [ "${#host_fs_types[*]}" -gt 0 ]; then
        module_check_mount $_mod || return 1
    else
        # skip this module
        return 1
    fi

    for _moddep in $(module_depends $_mod); do
        # handle deps as if they were manually added
        strstr " $add_dracutmodules " " $_moddep " || \
            add_dracutmodules+=" $_moddep "
        strstr " $force_add_dracutmodules " " $_moddep " || \
            force_add_dracutmodules+=" $_moddep "
        # if a module we depend on fail, fail also
        check_module $_moddep || return 1
    done

    strstr " $mods_to_load " " $_mod " || \
        mods_to_load+=" $_mod "

    return 0
}

# check_module <dracut module> [<use_as_dep>]
# check if a dracut module is to be used in the initramfs process
# if <use_as_dep> is set, then the process also keeps track
# that the modules were checked for the dependency tracking process
check_module() {
    local _mod=$1
    local _moddir=$(echo ${dracutbasedir}/modules.d/??${1})
    local _ret
    local _moddep
    # If we are already scheduled to be loaded, no need to check again.
    strstr " $mods_to_load " " $_mod " && return 0
    strstr " $mods_checked_as_dep " " $_mod " && return 1

    # This should never happen, but...
    [[ -d $_moddir ]] || return 1

    [[ $2 ]] || mods_checked_as_dep+=" $_mod "

    strstr " $omit_dracutmodules " " $_mod " && return 1

    if strstr " $dracutmodules $add_dracutmodules $force_add_dracutmodules" " $_mod "; then
        if strstr " $force_add_dracutmodules" " $_mod"; then
            module_check $_mod 1; ret=$?
        else
            module_check $_mod 0; ret=$?
        fi
        # explicit module, so also accept ret=255
        [[ $ret = 0 || $ret = 255 ]] || return 1
    else
        # module not in our list
        if [[ $dracutmodules = all ]]; then
            # check, if we can and should install this module
            module_check $_mod || return 1
        else
            # skip this module
            return 1
        fi
    fi

    for _moddep in $(module_depends $_mod); do
        # handle deps as if they were manually added
        strstr " $add_dracutmodules " " $_moddep " || \
            add_dracutmodules+=" $_moddep "
        strstr " $force_add_dracutmodules " " $_moddep " || \
            force_add_dracutmodules+=" $_moddep "
        # if a module we depend on fail, fail also
        check_module $_moddep || return 1
    done

    strstr " $mods_to_load " " $_mod " || \
        mods_to_load+=" $_mod "

    return 0
}

# for_each_module_dir <func>
# execute "<func> <dracut module> 1"
for_each_module_dir() {
    local _modcheck
    local _mod
    local _moddir
    local _func
    _func=$1
    for _moddir in "$dracutbasedir/modules.d"/[0-9][0-9]*; do
        _mod=${_moddir##*/}; _mod=${_mod#[0-9][0-9]}
        $_func $_mod 1
    done

    # Report any missing dracut modules, the user has specified
    _modcheck="$add_dracutmodules $force_add_dracutmodules"
    [[ $dracutmodules != all ]] && _modcheck="$m $dracutmodules"
    for _mod in $_modcheck; do
        strstr "$mods_to_load" "$_mod" && continue
        strstr "$omit_dracutmodules" "$_mod" && continue
        derror "Dracut module \"$_mod\" cannot be found."
    done
}

# Install a single kernel module along with any firmware it may require.
# $1 = full path to kernel module to install
install_kmod_with_fw() {
    # no need to go further if the module is already installed
    [[ -e "${initdir}/lib/modules/$kernel/${1##*/lib/modules/$kernel/}" ]] \
        && return 0

    if [[ $omit_drivers ]]; then
        local _kmod=${1##*/}
        _kmod=${_kmod%.ko}
        _kmod=${_kmod/-/_}
        if [[ "$_kmod" =~ $omit_drivers ]]; then
            dinfo "Omitting driver $_kmod"
            return 1
        fi
        if [[ "${1##*/lib/modules/$kernel/}" =~ $omit_drivers ]]; then
            dinfo "Omitting driver $_kmod"
            return 1
        fi
    fi

    inst_simple "$1" "/lib/modules/$kernel/${1##*/lib/modules/$kernel/}" \
        || return $?

    local _modname=${1##*/} _fwdir _found _fw
    _modname=${_modname%.ko*}
    for _fw in $(modinfo -k $kernel -F firmware $1 2>/dev/null); do
        _found=''
        for _fwdir in $fw_dir; do
            if [[ -d $_fwdir && -f $_fwdir/$_fw ]]; then
                inst_simple "$_fwdir/$_fw" "/lib/firmware/$_fw"
                _found=yes
            fi
        done
        if [[ $_found != yes ]]; then
            if ! grep -qe "\<${_modname//-/_}\>" /proc/modules; then
                dinfo "Possible missing firmware \"${_fw}\" for kernel module" \
                    "\"${_modname}.ko\""
            else
                dwarn "Possible missing firmware \"${_fw}\" for kernel module" \
                    "\"${_modname}.ko\""
            fi
        fi
    done
    return 0
}

# Do something with all the dependencies of a kernel module.
# Note that kernel modules depend on themselves using the technique we use
# $1 = function to call for each dependency we find
#      It will be passed the full path to the found kernel module
# $2 = module to get dependencies for
# rest of args = arguments to modprobe
# _fderr specifies FD passed from surrounding scope
for_each_kmod_dep() {
    local _func=$1 _kmod=$2 _cmd _modpath _options _found=0
    shift 2
    modprobe "$@" --ignore-install --show-depends $_kmod 2>&${_fderr} | (
        while read _cmd _modpath _options; do
            [[ $_cmd = insmod ]] || continue
            $_func ${_modpath} || exit $?
            _found=1
        done
        [[ $_found -eq 0 ]] && exit 1
        exit 0
    )
}

# filter kernel modules to install certain modules that meet specific
# requirements.
# $1 = search only in subdirectory of /kernel/$1
# $2 = function to call with module name to filter.
#      This function will be passed the full path to the module to test.
# The behaviour of this function can vary depending on whether $hostonly is set.
# If it is, we will only look at modules that are already in memory.
# If it is not, we will look at all kernel modules
# This function returns the full filenames of modules that match $1
filter_kernel_modules_by_path () (
    local _modname _filtercmd
    if ! [[ $hostonly ]]; then
        _filtercmd='find "$srcmods/kernel/$1" "$srcmods/extra"'
        _filtercmd+=' "$srcmods/weak-updates" -name "*.ko" -o -name "*.ko.gz"'
        _filtercmd+=' -o -name "*.ko.xz"'
        _filtercmd+=' 2>/dev/null'
    else
        _filtercmd='cut -d " " -f 1 </proc/modules|xargs modinfo -F filename '
        _filtercmd+='-k $kernel 2>/dev/null'
    fi
    for _modname in $(eval $_filtercmd); do
        case $_modname in
            *.ko) "$2" "$_modname" && echo "$_modname";;
            *.ko.gz) gzip -dc "$_modname" > $initdir/$$.ko
                $2 $initdir/$$.ko && echo "$_modname"
                rm -f $initdir/$$.ko
                ;;
            *.ko.xz) xz -dc "$_modname" > $initdir/$$.ko
                $2 $initdir/$$.ko && echo "$_modname"
                rm -f $initdir/$$.ko
                ;;
        esac
    done
)
find_kernel_modules_by_path () (
    if ! [[ $hostonly ]]; then
        find "$srcmods/kernel/$1" "$srcmods/extra" "$srcmods/weak-updates" \
          -name "*.ko" -o -name "*.ko.gz" -o -name "*.ko.xz" 2>/dev/null
    else
        cut -d " " -f 1 </proc/modules \
        | xargs modinfo -F filename -k $kernel 2>/dev/null
    fi
)

filter_kernel_modules () {
    filter_kernel_modules_by_path  drivers  "$1"
}

find_kernel_modules () {
    find_kernel_modules_by_path  drivers
}

# instmods <kernel module> [<kernel module> ... ]
# instmods <kernel subsystem>
# install kernel modules along with all their dependencies.
# <kernel subsystem> can be e.g. "=block" or "=drivers/usb/storage"
instmods() {
    [[ $no_kernel = yes ]] && return
    # called [sub]functions inherit _fderr
    local _fderr=9

    function inst1mod() {
        local _mod="$1"
        case $_mod in
            =*)
                # This introduces 2 incompatible meanings for =* arguments
                # to instmods.  We need to decide which one to keep.
                if [[ $_mod = =ata && -f $srcmods/modules.block ]]; then
                    ( [[ "$_mpargs" ]] && echo $_mpargs
                      egrep 'ata|ahci' "${srcmods}/modules.block" ) \
                    | instmods
                elif [ -f $srcmods/modules.${_mod#=} ]; then
                    ( [[ "$_mpargs" ]] && echo $_mpargs
                      cat "${srcmods}/modules.${_mod#=}" ) \
                    | instmods
                else
                    ( [[ "$_mpargs" ]] && echo $_mpargs
                      find "$srcmods" -path "*/${_mod#=}/*" ) \
                    | instmods
                fi
                ;;
            --*) _mpargs+=" $_mod" ;;
            i2o_scsi) return ;; # Do not load this diagnostic-only module
            *)
                # if we are already installed, skip this module and go on
                # to the next one.
                [[ -f $initdir/$1 ]] && return

                if [[ $omit_drivers ]] && [[ "$1" =~ $omit_drivers ]]; then
                    dinfo "Omitting driver ${_mod##$srcmods}"
                    return
                fi

                _mod=${_mod##*/}
                # If we are building a host-specific initramfs and this
                # module is not already loaded, move on to the next one.
                [[ $hostonly ]] && ! grep -qe "\<${_mod//-/_}\>" /proc/modules \
                    && ! echo $add_drivers | grep -qe "\<${_mod}\>" \
                    && return

                # We use '-d' option in modprobe only if modules prefix path
                # differs from default '/'.  This allows us to use Dracut with
                # old version of modprobe which doesn't have '-d' option.
                local _moddirname=${srcmods%%/lib/modules/*}
                [[ -n ${_moddirname} ]] && _moddirname="-d ${_moddirname}/"

                # ok, load the module, all its dependencies, and any firmware
                # it may require
                for_each_kmod_dep install_kmod_with_fw $_mod \
                    --set-version $kernel ${_moddirname} $_mpargs
                ((_ret+=$?))
                ;;
        esac
    }

    function instmods_1() {
        local _ret=0 _mod _mpargs
        if (($# == 0)); then  # filenames from stdin
            while read _mod; do
                inst1mod "${_mod%.ko*}"
            done
        fi
        while (($# > 0)); do  # filenames as arguments
            inst1mod ${1%.ko*}
            shift
        done
        return $_ret
    }

    # Capture all stderr from modprobe to _fderr. We could use {var}>...
    # redirections, but that would make dracut require bash4 at least.
    eval "( instmods_1 \"\$@\" ) ${_fderr}>&1" \
    | egrep -v 'FATAL: Module .* not found.' | derror
    return $?
}