#!/bin/sh
# SPDX-License-Identifier: LGPL-2.1-or-later
set -e

# This is a build script for OS image generation using mkosi (https://github.com/systemd/mkosi).
# Simply invoke "mkosi" in the project directory to build an OS image.

ASAN_OPTIONS=strict_string_checks=1:detect_stack_use_after_return=1:check_initialization_order=1:strict_init_order=1:disable_coredump=0:use_madv_dontdump=1
UBSAN_OPTIONS=print_stacktrace=1:print_summary=1:halt_on_error=1

# On Fedora "ld" is (unfortunately — if you ask me) managed via
# "alternatives". Since we'd like to support building images in environments
# with only /usr/ around (e.g. mkosi's UsrOnly=1 option), we have the problem
# that /usr/bin/ld is a symlink that points to a non-existing file in
# /etc/alternative/ in this mode. Let's work around this for now by manually
# redirect "ld" to "ld.bfd", i.e. circumventing the /usr/bin/ld symlink.
if [ ! -x /usr/bin/ld ] && [ -x /usr/bin/ld.bfd ]; then
        mkdir -p "$HOME"/bin
        ln -s /usr/bin/ld.bfd "$HOME"/bin/ld
        PATH="$HOME/bin:$PATH"
fi

# If mkosi.builddir/ exists mkosi will set $BUILDDIR to it, let's then use it
# as out-of-tree build dir. Otherwise, let's make up our own builddir.
[ -z "$BUILDDIR" ] && BUILDDIR=build

# Meson uses Python 3 and requires a locale with an UTF-8 character map.
# Not running under UTF-8 makes the `ninja test` step break with a CodecError.
# So let's ensure we're running under UTF-8.
#
# If our current locale already is UTF-8, then we don't need to do anything:
if [ "$(locale charmap 2>/dev/null)" != "UTF-8" ] ; then
        # Try using C.UTF-8 locale, if available. This locale is not shipped
        # by upstream glibc, so it's not available in all distros.
        # (In particular, it's not available in Arch Linux.)
        if locale -a | grep -q -E "C.UTF-8|C.utf8"; then
                export LC_CTYPE=C.UTF-8
        # Finally, try something like en_US.UTF-8, which should be
        # available in Arch Linux, but is not present in Debian's
        # minimal image in our mkosi config.
        elif locale -a | grep -q en_US.utf8; then
                export LC_CTYPE=en_US.UTF-8
        else
                # If nothing works, fail early.
                echo "*** Could not find a valid locale that supports UTF-8. ***" >&2
                exit 1
        fi
fi

if [ ! -f "$BUILDDIR"/build.ninja ] ; then
        sysvinit_path=$(realpath /etc/init.d)

        init_path=$(realpath /sbin/init 2>/dev/null)
        if [ -z "$init_path" ] ; then
                rootprefix=""
        else
                rootprefix=${init_path%/lib/systemd/systemd}
                rootprefix=/${rootprefix#/}
        fi

        meson "$BUILDDIR" \
                -D "sysvinit-path=$sysvinit_path" \
                -D "rootprefix=$rootprefix" \
                -D man=false \
                -D translations=false \
                -D version-tag="${VERSION_TAG}" \
                -D mode=developer \
                -D b_sanitize="${SANITIZERS:-none}" \
                -D install-tests=true
fi

cd "$BUILDDIR"
ninja "$@"
if [ "$WITH_TESTS" = 1 ] ; then
        for id in 1 2 3; do
                getent group $id >/dev/null || groupadd -g $id testgroup$id
        done

        if [ -n "$SANITIZERS" ]; then
                export ASAN_OPTIONS="$ASAN_OPTIONS"
                export UBSAN_OPTIONS="$UBSAN_OPTIONS"
                TIMEOUT_MULTIPLIER=3
        else
                TIMEOUT_MULTIPLIER=1
        fi

        meson test --timeout-multiplier=$TIMEOUT_MULTIPLIER
fi
cd "$SRCDIR"

# Ubuntu Focal is stuck with meson 0.53.0.
if [ "$(meson -v | cut -d . -f 2)" -gt 53 ] ; then
        meson install -C "$BUILDDIR" --quiet --no-rebuild --only-changed
else
        meson install -C "$BUILDDIR" --no-rebuild --only-changed
fi

mkdir -p "$DESTDIR"/etc

cat >"$DESTDIR"/etc/issue <<EOF
\S (built from systemd tree)
Kernel \r on an \m (\l)

EOF

if [ -n "$IMAGE_ID" ] ; then
        mkdir -p "$DESTDIR"/usr/lib
        sed -n \
                -e '/^IMAGE_ID=/!p' \
                -e "\$aIMAGE_ID=$IMAGE_ID" <"/usr/lib/os-release" >"${DESTDIR}/usr/lib/os-release"

        OSRELEASEFILE="$DESTDIR"/usr/lib/os-release
else
        OSRELEASEFILE=/usr/lib/os-release
fi


if [ -n "$IMAGE_VERSION" ] ; then
        mkdir -p "$DESTDIR"/usr/lib
        sed -n \
                -e '/^IMAGE_VERSION=/!p' \
                -e "\$aIMAGE_VERSION=$IMAGE_VERSION" <$OSRELEASEFILE >"/tmp/os-release.tmp"

        cat /tmp/os-release.tmp > "$DESTDIR"/usr/lib/os-release
        rm /tmp/os-release.tmp
fi

# If $CI_BUILD is set, copy over the CI service which executes a service check
# after boot and then shuts down the machine
if [ -n "$CI_BUILD" ]; then
        mkdir -p "$DESTDIR/usr/lib/systemd/system"
        cp -v "$SRCDIR/test/mkosi-check-and-shutdown.service" "$DESTDIR/usr/lib/systemd/system/mkosi-check-and-shutdown.service"
        cp -v "$SRCDIR/test/mkosi-check-and-shutdown.sh" "$DESTDIR/usr/lib/systemd/mkosi-check-and-shutdown.sh"
        chmod +x "$DESTDIR/usr/lib/systemd/mkosi-check-and-shutdown.sh"
fi

if [ -n "$SANITIZERS" ]; then
        LD_PRELOAD=$(ldd $BUILDDIR/systemd | grep libasan.so | awk '{print $3}')

        mkdir -p "$DESTDIR/etc/systemd/system.conf.d"

        cat > "$DESTDIR/etc/systemd/system.conf.d/10-asan.conf" <<EOF
[Manager]
ManagerEnvironment=ASAN_OPTIONS=$ASAN_OPTIONS\\
                   UBSAN_OPTIONS=$UBSAN_OPTIONS\\
                   LD_PRELOAD=$LD_PRELOAD
DefaultEnvironment=ASAN_OPTIONS=$ASAN_OPTIONS\\
                   UBSAN_OPTIONS=$UBSAN_OPTIONS\\
                   LD_PRELOAD=$LD_PRELOAD
EOF

        # ASAN logs to stderr by default. However, journald's stderr is connected to /dev/null, so we lose
        # all the ASAN logs. To rectify that, let's connect journald's stdout to the console so that any
        # sanitizer failures appear directly on the user's console.
        mkdir -p "$DESTDIR/etc/systemd/system/systemd-journald.service.d"

        cat > "$DESTDIR/etc/systemd/system/systemd-journald.service.d/10-stdout-tty.conf" <<EOF
[Service]
StandardOutput=tty
EOF

        # Both systemd and util-linux's login call vhangup() on /dev/console which disconnects all users.
        # This means systemd-journald can't log to /dev/console even if we configure `StandardOutput=tty`. As
        # a workaround, we modify console-getty.service to disable systemd's vhangup() and disallow login
        # from calling vhangup() so that journald's ASAN logs correctly end up in the console.

        mkdir -p "$DESTDIR/etc/systemd/system/console-getty.service.d"

        cat > "$DESTDIR/etc/systemd/system/console-getty.service.d/10-no-vhangup.conf" <<EOF
[Service]
TTYVHangup=no
CapabilityBoundingSet=~CAP_SYS_TTY_CONFIG
EOF
fi