mkinitrd

#!/bin/bash
#
# Copyright (c) 2018 YADRO
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.
#
set -e

declare -a POSITIONAL
declare -a INCLUDES
declare -a DRACUT_OPTS
declare -a KMODS
CURDIR=$(dirname $(realpath "${BASH_SOURCE[0]}"))
GUEST="$CURDIR/guest"
KDUMP_BASE_KMODS+=(virtio_pci virtio_net virtio_blk virtio_console)
KMODS+=(${KDUMP_BASE_KMODS[@]} virtio_scsi virtio-rng sg sd_mod)
MODULES=(base systemd terminfo)
INSTALL=(zcat zless zgrep grep gzip cut sed awk tr ps tar nproc)
source "$CURDIR/lib"
systemddir=/usr/lib/systemd
sysunitdir="$systemddir/system"
targetdeps="$sysunitdir/multi-user.target.wants"

usage() {
    cat <<EOF
Usage: $0 [options] <out-file> <kernel-image>

Options:
  -k, --with-kdump         Build kdump kernel
  -v, --verbose            Extra output
EOF
}

while [ $# -gt 0 ]; do
    case "$1" in
        --with-kdump|-k)
            KDUMP=1
            shift
            ;;
        --verbose|-v)
            VERBOSE=-v
            shift
            ;;
        --kmoddir)
            DRACUT_OPTS+=(-k "$2")
            shift 2
            ;;
        --fwdir)
            DRACUT_OPTS+=(--fwdir "$2")
            shift 2
            ;;
        --module|-m)
            KMODS+=($2)
            shift 2
            ;;
        --install|-i)
            if [ -x "$(pwd)/$2" ]; then
                INSTALL+=($(realpath "$(pwd)/$2"))
            else
                INSTALL+=("$2")
            fi
            shift 2
            ;;
        --include|-I)
            src=$(cut -d: -f1 <<< "$2")
            if [ ! -r "$src" ]; then
                die "Can't find file at '$src'"
            fi
            dst=$(cut -d: -f2 <<< "$2")
            DRACUT_OPTS+=(--include $src $dst)
            shift 2
            ;;
        --net)
            NETWORK=y
            shift
            ;;
        *)
            POSITIONAL+=("$1")
            shift
            ;;
    esac
done

if [ ${#POSITIONAL[@]} -ne 2 ]; then
    usage
    exit 1
fi
OUT="${POSITIONAL[0]}"
KIMG="${POSITIONAL[1]}"
[ -r "$KIMG" ] || die "Can't read kernel: $KIMG"
KVER=$(strings "$KIMG" | grep -oP 'Linux version \K\S+') || :
[ -z "$KVER" ] && KVER=$(file "$KIMG" | grep -oP ', Version \K\S+') || :
[ -n "$KVER" ] || die "Can't extract kernel version from: $KIMG"
emptydir=$(mktemp -d)
ktestdir=$(mktemp -d)
entrypoint="$GUEST/profile"

check_progs() {
    local notfound=0
    for prog in "$@"; do
        if ! command -v "$prog" 2>/dev/null 1>&2; then
            echo "ERROR: Can't find \"$prog\" in \$PATH"
            ((notfound++))
        fi
    done
    if ((notfound > 0)); then
        die
    fi
}

check_kmods() {
    local kmod_dir="/lib/modules/$KVER"
    local notfound=0
    for mod in "$@"; do
        # Handle dash to underscore aliasing
        mod=$(sed 's|[-_]|\[-_\]|' <<< "$mod")
        grep -qw "$mod" "$kmod_dir/modules."{builtin,dep} && continue
        # test if a built-in alias is requested
        tr '\0' '\n' < "$kmod_dir/modules.builtin.modinfo" | \
           grep -qwE "\w+\.alias=$mod" && continue
        echo "ERROR: Kernel module $mod is missing in $kmod_dir"
        ((notfound++))
    done
    if ((notfound > 0)); then
        die
    fi
}

libdirs() {
    local -a libdirs
    if [[ $(ldd /bin/sh) == */lib64/* ]] && [ -d /lib64 ]; then
        libdirs+=(/lib64)
        [ -d /usr/lib64 ] && libdirs+=(/usr/lib64)
    else
        libdirs+=(/lib)
        [ -d /usr/lib ] && libdirs+=(/usr/lib)
    fi
    echo "${libdirs[@]}"
    return 0
}

inst_libdir_file() {
    for ldir in $(libdirs); do
        for p in "$@"; do
            match=$(ls $ldir/$p 2>/dev/null) || continue
            for m in $match; do
                INCLUDES+=(--include "$m" "$m")
            done
        done
    done
}

if [ -n "$NETWORK" ]; then
    NET_INSTALL=(ip dhclient arping ping ping6 hostname)
    # Install resolver from glibc
    _arch=$(uname -m)
    inst_libdir_file {"tls/$_arch/",tls/,"$_arch/",}"libnss_dns.so.*" \
                     {"tls/$_arch/",tls/,"$_arch/",}"libnss_mdns4_minimal.so.*"
    INSTALL+=("${NET_INSTALL[@]}")
    MODULES+=(kernel-network-modules)
fi

if [ -n "$KDUMP" ]; then
    bootdir=$(dirname $OUT)/boot
    mkdir -p "$bootdir"
    kernel=$(find /boot -name 'vmlinu[x|z]')
    cp "$kernel" "$bootdir"
    KDUMP_INSTALL=(gzip nproc makedumpfile scp grep cut tar)

    check_progs "${KDUMP_INSTALL[@]}"
    check_kmods "${KDUMP_BASE_KMODS[@]}"
    dracut -N --force                                                         \
           "${DRACUT_OPTS[@]}"                                                \
           -m "base"                                                          \
           --filesystems "xfs"                                                \
           --install "${KDUMP_INSTALL[*]}"                                    \
           --include $emptydir /crashes                                       \
           --include "$GUEST/collect-crash" /.profile                         \
           --drivers="${KDUMP_BASE_KMODS[*]}"                                 \
           $VERBOSE                                                           \
           "$bootdir/initrd-kdump" "$KVER"

    INCLUDES+=(--include "$bootdir" /boot)
    INSTALL+=(kexec)
fi

check_progs "${INSTALL[@]}"
check_kmods "${KMODS[@]}"
export DRACUT_RESOLVE_DEPS=1
dracut -N --force                                                             \
       "${DRACUT_OPTS[@]}"                                                    \
       -m "${MODULES[*]}"                                                     \
       --filesystems "ext2"                                                   \
       --install "${INSTALL[*]}"                                              \
       --include $CURDIR/multi-user.target.wants                              \
                 $sysunitdir/multi-user.target.wants                          \
       --include $GUEST/cmdline.service $sysunitdir/ktest-cmdline.service     \
       --include $GUEST/cmdline.sh /bin/ktest-cmdline                         \
       --include $GUEST/debugfs.mount $sysunitdir/sys-kernel-debug.mount      \
       --include $emptydir /var/lib/dhcp                                      \
       --include $GUEST/dhclient-script.sh /sbin/dhclient-script              \
       --include $GUEST/dhclient.service $sysunitdir/dhclient.service         \
       --include $entrypoint /.profile                                        \
       --include $CURDIR/ktest.service $sysunitdir/ktest.service              \
       --include $CURDIR/ktest.sh /bin/ktest                                  \
       --include $CURDIR/disk-by-serial /bin/disk-by-serial                   \
       "${INCLUDES[@]}"                                                       \
       --drivers="${KMODS[*]}"                                                \
       $VERBOSE                                                               \
       "$OUT" "$KVER"

if [ -n "$FILE_UID" ]; then
    chown $FILE_UID $OUT
fi