path: root/debian/tests/utils/init

#!/bin/sh

# PID1 at initramfs stage
#
# Copyright © 2021-2022 Guilhem Moulin <guilhem@debian.org>
#
# 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 3 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/>.

set -eux
PATH="/usr/sbin:/usr/bin:/sbin:/bin"
export PATH

trap "echo \"ALERT!  Couldn't setup system, dropping to a shell.\" >&2; sh -i" 0

# set VT100 autowrap mode again (QEMU might mess the terminal up)
printf '\033[?7h'

mount -t devtmpfs -o noexec,nosuid,mode=0755 udev /dev

mkdir /dev/pts /proc /run /sys
mount -t devpts -o noexec,nosuid,gid=5,mode=0620 devpts /dev/pts
mount -t proc -o nodev,noexec,nosuid proc /proc
mount -t tmpfs -o nodev,noexec,nosuid,size=5%,mode=0755 tmpfs /run
mount -t sysfs -o nodev,noexec,nosuid sysfs /sys

modprobe virtio_rng # /dev/hwrng (avoid entropy starvation)
modprobe virtio_pci
modprobe virtio_blk # /dev/vd[a-z]
modprobe virtio_console # /dev/hvc[0-7]

# start udevd
/lib/systemd/systemd-udevd --daemon
udevadm trigger --type=subsystems --action=add
udevadm trigger --type=devices --action=add
udevadm settle

. /init.conf

# https://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_type_GUIDs
GUID_TYPE_MBR="024DEE41-33E7-11D3-9D69-0008C781F39F"       # MBR partition scheme
GUID_TYPE_EFI="C12A7328-F81F-11D2-BA4B-00A0C93EC93B"       # EFI boot partition
GUID_TYPE_BIOS_boot="21686148-6449-6E6F-744E-656564454649" # BIOS boot partition
GUID_TYPE_Linux_FS="0FC63DAF-8483-4772-8E79-3D69D8477DE4"  # Linux filesystem data
GUID_TYPE_LUKS="CA7D7CCB-63ED-4C53-861C-1742536059CC"      # LUKS partition
GUID_TYPE_DMCRYPT="7FFEC5C9-2D00-49B7-8941-3EA10A5586B7"   # Plain dm-crypt partition
GUID_TYPE_LVM="E6D6D379-F507-44C2-A23C-238F2A3DF928"       # Logical Volume Manager partition
GUID_TYPE_RAID="A19D880F-05FC-4D3B-A006-743F0F84911E"      # RAID partition

if [ "$BOOT" = "bios" ]; then
    BOOT_PARTITION_SIZE=2
    BOOT_PARTITION_TYPE="$GUID_TYPE_BIOS_boot"
elif [ "$BOOT" = "efi" ]; then
    BOOT_PARTITION_SIZE=63
    BOOT_PARTITION_TYPE="$GUID_TYPE_EFI"
else
    echo "ERROR unknown boot method '$BOOT'" >&2
    exit 1
fi

# format the target disk and create a BIOS/EFI partition
sfdisk /dev/vda <<-EOF
	label: gpt
	unit: sectors

	start=$((1024*2)), size=$((BOOT_PARTITION_SIZE*1024*2)), type=$BOOT_PARTITION_TYPE
EOF
udevadm settle

ROOT="/target"
mkdir -m0755 "$ROOT"
# /init.setup is expected to create the root filesystem of the target
# system and mount it (alongside other filesystems) on $ROOT
. /init.setup
udevadm settle

# inspired by debootstrap's /usr/share/debootstrap/functions
if [ "$MERGED_USR" = "yes" ]; then
    case "$ARCH" in
        amd64) libdir="lib32 lib64 libx32";;
        i386) libdir="lib64 libx32";;
        mips|mipsel) libdir="lib32 lib64";;
        mips64*|mipsn32*) libdir="lib32 lib64 libo32";;
        loongarch64*) libdir="lib32 lib64";;
        powerpc) libdir="lib64";;
        ppc64) libdir="lib32 lib64";;
        ppc64el) libdir="lib64";;
        s390x) libdir="lib32";;
        sparc) libdir="lib64";;
        sparc64) libdir="lib32 lib64";;
        x32) libdir="lib32 lib64 libx32";;
        *) libdir="";;
    esac
    for dir in bin sbin lib $libdir; do
        ln -s "usr/$dir" "$ROOT/$dir"
        mkdir -p "$ROOT/usr/$dir"
    done
fi

mkdir /media
DEBIAN_DIST="$(blkid -l -t LABEL="debian_dist" -o device)"
mount -t ext2 -o ro "$DEBIAN_DIST" /media
for pkg in /media/__stage1__/*.deb; do
    dpkg-deb --fsys-tarfile "$pkg" | tar -C "$ROOT" -xf - --keep-directory-symlink
done

# setup hosts(5) and hostname(5)
echo "$HOSTNAME" >"$ROOT/etc/hostname"
echo "127.0.0.1 localhost $HOSTNAME" >"$ROOT/etc/hosts"

# EFI
if [ "$BOOT" = "efi" ]; then
    modprobe efivarfs
    mount -t efivarfs efivarfs /sys/firmware/efi/efivars

    mkfs.vfat -F 32 /dev/vda1
    mkdir "$ROOT/boot/efi"
    mount -t vfat /dev/vda1 "$ROOT/boot/efi"

    cat >>"$ROOT/etc/fstab" <<-EOF
		UUID=$(blkid -s UUID -o value /dev/vda1) /boot/efi auto defaults 0 2
	EOF
fi

# bind mount pseudo and temporary filesystems to "$ROOT"
mount -no bind /dev "$ROOT/dev"
mount -no bind /proc "$ROOT/proc"
mount -no bind /sys "$ROOT/sys"
mount -t tmpfs -o nodev,noexec,nosuid,size=5%,mode=0755 tmpfs "$ROOT/run"

# prevent any services from starting during package installation, taken
# from debootstrap(8)
cat >"$ROOT/usr/sbin/policy-rc.d" <<-EOF
	#!/bin/sh
	exit 101
EOF
chmod +x "$ROOT/usr/sbin/policy-rc.d"

mv "$ROOT/sbin/start-stop-daemon" "$ROOT/sbin/start-stop-daemon.REAL"
cat >"$ROOT/sbin/start-stop-daemon" <<-EOF
	#!/bin/sh
	echo
	echo "Warning: Fake start-stop-daemon called, doing nothing"
EOF
chmod +x "$ROOT/usr/sbin/policy-rc.d" "$ROOT/sbin/start-stop-daemon"

DEBIAN_FRONTEND="noninteractive"
DEBCONF_NONINTERACTIVE_SEEN="true"
export DEBIAN_FRONTEND DEBCONF_NONINTERACTIVE_SEEN

# debootstrap the target system
mkdir "$ROOT/media"
mount -no move /media "$ROOT/media"
cp -p /debootstrap "$ROOT/debootstrap"
chroot "$ROOT" /debootstrap
rm -f "$ROOT/debootstrap"

# use MODULES=dep (if it works with fewer modules then it also works
# with the default MODULES=most)
mkdir -p "$ROOT/etc/initramfs-tools/conf.d"
echo "MODULES=dep" >"$ROOT/etc/initramfs-tools/conf.d/modules"

cp /init.preinst "$ROOT/init.preinst"
chroot "$ROOT" /bin/sh -eux /init.preinst
rm -f "$ROOT/init.preinst"
udevadm settle

# install extra packages
chroot "$ROOT" apt-get -oAPT::Sandbox::User="root" install --yes $PACKAGES
rm -f "$ROOT/etc/apt/sources.list"

# configure and install GRUB
cat >"$ROOT/etc/default/grub" <<-EOF
	GRUB_DEFAULT=0
	GRUB_TIMEOUT=0
	GRUB_CMDLINE_LINUX_DEFAULT=""
	GRUB_CMDLINE_LINUX="console=$CONSOLE,115200n8"
	GRUB_DISABLE_RECOVERY=true
	GRUB_TERMINAL="console serial"
	GRUB_SERIAL_COMMAND="serial --speed=115200"
EOF
chroot "$ROOT" grub-install --no-floppy --modules=part_gpt /dev/vda
chroot "$ROOT" update-grub

chroot "$ROOT" busybox passwd -d root # make root account passwordless

# show some system info right after login to ease troubleshooting
cat >"$ROOT/root/.profile" <<-EOF
	run_verbose() {
	    printf "\\\`%s\\\` output:\\\\n" "\$*"
	    "\$@"
	}
	stty cols 150
	run_verbose dmsetup table
	run_verbose lsblk
	run_verbose df -h
EOF

cat >"$ROOT/root/.inputrc" <<-EOF
	# disabled bracketed paste mode
	set enable-bracketed-paste off
EOF

if [ -d "$ROOT/etc/systemd/system" ]; then
    # systemd
    if [ -c "$ROOT/dev/hvc0" ]; then
        # serial-getty@ttyS0.service is automatically enabled due to the console= kernel parameter
        ln -s "/dev/null" "$ROOT/etc/systemd/system/serial-getty@ttyS0.service"
        ln -s "/lib/systemd/system/serial-getty@.service" \
            "$ROOT/etc/systemd/system/getty.target.wants/serial-getty@hvc0.service"
    fi

    # mask all timer units
    for t in "$ROOT"/lib/systemd/system/*.timer; do
        test -f "$t" || continue
        ln -s "/dev/null" "$ROOT/etc/systemd/system/${t##*/}"
    done

    # mask systemd-firstboot.service
    ln -s "/dev/null" "/root/etc/systemd/system/systemd-firstboot.service"
fi

if [ -f "$ROOT/etc/inittab" ]; then
    # sysvinit
    if [ -c "$ROOT/dev/hvc0" ]; then
        echo "h0:2345:respawn:/sbin/agetty -8 -L 115200 hvc0 linux"
    else
        echo "S0:23:respawn:/sbin/getty -8 -L 115200 $CONSOLE linux"
    fi >>"$ROOT/etc/inittab"
fi

if [ -f /init.postinst ]; then
    cp /init.postinst "$ROOT/init.postinst"
    chroot "$ROOT" /bin/sh -eux /init.postinst
    rm -f "$ROOT/init.postinst"
fi

# allow service startup again
mv "$ROOT/sbin/start-stop-daemon.REAL" "$ROOT/sbin/start-stop-daemon"
rm "$ROOT/usr/sbin/policy-rc.d"

# unmount pseudo filesystems from the target system
umount "$ROOT/dev"
umount "$ROOT/proc"
umount "$ROOT/sys"

if [ "$BOOT" = "efi" ]; then
    umount "$ROOT/boot/efi"
fi
umount "$ROOT/media"
umount "$ROOT/run"

# /init.bottom is expected to umount $ROOT and its submounts
ROOT="$ROOT" sh -eux /init.bottom

# stop udevd
udevadm control --exit

# exiting this script yields "Kernel panic - not syncing: Attempted to
# kill init!", so give the asyncronous SysRq trigger a chance to power
# off (sending a racy C-d would still trigger a panic but we don't care)
echo o >/proc/sysrq-trigger
exec cat >/dev/null