Adjust merged-/usr as it's done by debootstrap

- implements the same as debootstrap in
   https://salsa.debian.org/installer-team/debootstrap/-/merge_requests/71
 - builds a temporary usr-is-merged package and upgrades to the real one
 - create merged-/usr chroots for unstable and testing (which will
   become Debian 12 Bookworm)
 - add a dedicated merged-/usr section to the manual page
This commit is contained in:
Johannes Schauer Marin Rodrigues 2022-07-26 18:30:52 +02:00
parent 7cec147b9e
commit d91a18a350
Signed by untrusted user: josch
GPG key ID: F2CBA5C78FBD83E1
9 changed files with 170 additions and 27 deletions

15
hooks/merged-usr/essential00.sh Executable file
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@ -0,0 +1,15 @@
#!/bin/sh
set -eu
if [ "$MMDEBSTRAP_VERBOSITY" -ge 3 ]; then
set -x
fi
TARGET="$1"
APT_CONFIG=$MMDEBSTRAP_APT_CONFIG apt-get --yes install -oDPkg::Chroot-Directory="$TARGET" usr-is-merged
chroot "$TARGET" dpkg-query --showformat '${db:Status-Status}\n' --show usr-is-merged | grep -q '^installed$'
chroot "$TARGET" dpkg-query --showformat '${Source}\n' --show usr-is-merged | grep -q '^usrmerge$'
dpkg --compare-versions "1" "lt" "$(chroot "$TARGET" dpkg-query --showformat '${Version}\n' --show usr-is-merged)"

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@ -78,3 +78,34 @@ else
mkdir -p "$TARGET/usr/$dir"
done
fi
# now install an empty "usr-is-merged" package to avoid installing the
# usrmerge package on this system even after init-system-helpers starts
# depending on "usrmerge | usr-is-merged".
#
# This package will not end up in the final chroot because the essential
# hook replaces it with the actual usr-is-merged package from src:usrmerge.
tmpdir=$(mktemp --directory --tmpdir="$TARGET/tmp")
mkdir -p "$tmpdir/usr-is-merged/DEBIAN"
cat << END > "$tmpdir/usr-is-merged/DEBIAN/control"
Package: usr-is-merged
Priority: optional
Section: oldlibs
Maintainer: Johannes Schauer Marin Rodrigues <josch@debian.org>
Architecture: all
Multi-Arch: foreign
Source: mmdebstrap-dummy-usr-is-merged
Version: 1
Description: dummy package created by mmdebstrap merged-usr setup hook
This package was generated and installed by the mmdebstrap merged-usr
setup hook at /usr/share/mmdebstrap/hooks/merged-usr.
.
If this package is installed in the final chroot, then this is a bug
in mmdebstrap. Please report: https://gitlab.mister-muffin.de/josch/mmdebstrap
END
dpkg-deb --build "$tmpdir/usr-is-merged" "$tmpdir/usr-is-merged.deb"
dpkg --root="$TARGET" --log="$TARGET/var/log/dpkg.log" --install "$tmpdir/usr-is-merged.deb"
rm "$tmpdir/usr-is-merged.deb" "$tmpdir/usr-is-merged/DEBIAN/control"
rmdir "$tmpdir/usr-is-merged/DEBIAN" "$tmpdir/usr-is-merged" "$tmpdir"

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@ -0,0 +1,15 @@
#!/bin/sh
set -eu
if [ "$MMDEBSTRAP_VERBOSITY" -ge 3 ]; then
set -x
fi
TARGET="$1"
APT_CONFIG=$MMDEBSTRAP_APT_CONFIG apt-get --yes install -oDPkg::Chroot-Directory="$TARGET" usr-is-merged
chroot "$TARGET" dpkg-query --showformat '${db:Status-Status}\n' --show usr-is-merged | grep -q '^installed$'
chroot "$TARGET" dpkg-query --showformat '${Source}\n' --show usr-is-merged | grep -q '^usrmerge$'
dpkg --compare-versions "1" "lt" "$(chroot "$TARGET" dpkg-query --showformat '${Version}\n' --show usr-is-merged)"

53
hooks/no-merged-usr/setup00.sh Executable file
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@ -0,0 +1,53 @@
#!/bin/sh
#
# mmdebstrap does have a --no-merged-usr option but only as a no-op for
# debootstrap compatibility
#
# Using this hook script, you can emulate what debootstrap does to set up
# a system without merged-/usr even after the essential init-system-helpers
# package added a dependency on "usrmerge | usr-is-merged". By installing
# a dummy usr-is-merged package, it avoids pulling in the dependencies of
# the usrmerge package.
set -eu
if [ "$MMDEBSTRAP_VERBOSITY" -ge 3 ]; then
set -x
fi
TARGET="$1"
echo "Warning: starting with Debian 12 (Bookworm), systems without merged-/usr are not supported anymore" >&2
echo "this system will not be supported in the future" > "$TARGET/etc/unsupported-skip-usrmerge-conversion"
# now install an empty "usr-is-merged" package to avoid installing the
# usrmerge package on this system even after init-system-helpers starts
# depending on "usrmerge | usr-is-merged".
#
# This package will not end up in the final chroot because the essential
# hook replaces it with the actual usr-is-merged package from src:usrmerge.
tmpdir=$(mktemp --directory --tmpdir="$TARGET/tmp")
mkdir -p "$tmpdir/usr-is-merged/DEBIAN"
cat << END > "$tmpdir/usr-is-merged/DEBIAN/control"
Package: usr-is-merged
Priority: optional
Section: oldlibs
Maintainer: Johannes Schauer Marin Rodrigues <josch@debian.org>
Architecture: all
Multi-Arch: foreign
Source: mmdebstrap-dummy-usr-is-merged
Version: 1
Description: dummy package created by mmdebstrap no-merged-usr setup hook
This package was generated and installed by the mmdebstrap no-merged-usr
setup hook at /usr/share/mmdebstrap/hooks/no-merged-usr.
.
If this package is installed in the final chroot, then this is a bug
in mmdebstrap. Please report: https://gitlab.mister-muffin.de/josch/mmdebstrap
END
dpkg-deb --build "$tmpdir/usr-is-merged" "$tmpdir/usr-is-merged.deb"
dpkg --root="$TARGET" --log="$TARGET/var/log/dpkg.log" --install "$tmpdir/usr-is-merged.deb"
rm "$tmpdir/usr-is-merged.deb" "$tmpdir/usr-is-merged/DEBIAN/control"
rmdir "$tmpdir/usr-is-merged/DEBIAN" "$tmpdir/usr-is-merged" "$tmpdir"

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@ -266,6 +266,13 @@ END
pkgs="$(echo $pkgs) build-essential busybox gpg eatmydata"
# we need usr-is-merged to simulate debootstrap behaviour for all dists
# starting from Debian 12 (Bullseye)
case "$dist" in
oldstable|stable) : ;;
*) pkgs="$pkgs usr-is-merged" ;;
esac
APT_CONFIG="$rootdir/etc/apt/apt.conf" apt-get --yes install $pkgs
# to be able to also test gpg verification, we need to create a mirror
@ -654,7 +661,7 @@ fi
mirror="http://127.0.0.1/debian"
for dist in oldstable stable testing unstable; do
for variant in minbase buildd -; do
echo "running debootstrap --no-merged-usr --variant=$variant $dist \${TEMPDIR} $mirror"
echo "running debootstrap --variant=$variant $dist \${TEMPDIR} $mirror"
cat << END > shared/test.sh
#!/bin/sh
set -eu
@ -663,7 +670,14 @@ export SOURCE_DATE_EPOCH=$SOURCE_DATE_EPOCH
echo "SOURCE_DATE_EPOCH=\$SOURCE_DATE_EPOCH"
tmpdir="\$(mktemp -d)"
chmod 755 "\$tmpdir"
debootstrap --no-merged-usr --variant=$variant $dist "\$tmpdir" $mirror
case "$dist" in
oldstable|stable)
debootstrap --no-merged-usr --variant=$variant $dist "\$tmpdir" $mirror
;;
*)
debootstrap --merged-usr --variant=$variant $dist "\$tmpdir" $mirror
;;
esac
tar --sort=name --mtime=@$SOURCE_DATE_EPOCH --clamp-mtime --numeric-owner --one-file-system --xattrs -C "\$tmpdir" -c . > "$newcache/debian-$dist-$variant.tar"
rm -r "\$tmpdir"
END

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@ -6098,10 +6098,6 @@ package list is free of duplicates. So the following are equivalent:
--include=pkg1/stable,pkg2=1.0,pkg3-
--incl=pkg1/stable --incl="pkg2=1.0 pkg3-" --incl=pkg2=1.0,pkg3-
Example: setting up merged-/usr via the usrmerge package
--include=usrmerge
=item B<--components>=I<comp1>[,I<comp2>,...]
Comma or whitespace separated list of components like main, contrib and
@ -6148,18 +6144,7 @@ installed. At that point, the chroot directory does not contain any
executables and thus cannot be chroot-ed into. See section B<HOOKS> for more
information.
Example 1: Setup merged-/usr via symlinks, omitting the architecture specific
symlinks
--setup-hook='for d in bin sbin lib; do ln -s usr/$d "$1/$d";
mkdir -p "$1/usr/$d"; done'
Example 2: Setup merged-/usr using debootstrap-method which takes care of the
architecture specific symlinks
--setup-hook=/usr/share/mmdebstrap/hooks/merged-usr/setup00.sh
Example 3: Setup chroot for installing a sub-essential busybox-based chroot
Example: Setup chroot for installing a sub-essential busybox-based chroot
with --variant=custom
--include=dpkg,busybox,libc-bin,base-files,base-passwd,debianutils
@ -6170,8 +6155,8 @@ with --variant=custom
--setup-hook='echo root:x:0:0:root:/root:/bin/sh > "$1/etc/passwd"'
--setup-hook='printf "root:x:0:\nmail:x:8:\nutmp:x:43:\n" > "$1/etc/group"'
For a more elegant way to setup merged-/usr via symlinks and for setting up a
sub-essential busybox-based chroot, see the B<--hook-dir> option below.
For a more elegant way for setting up a sub-essential busybox-based chroot, see
the B<--hook-dir> option below.
=item B<--extract-hook>=I<command>
@ -6252,12 +6237,7 @@ Example 2: Setup chroot for installing a sub-essential busybox-based chroot
--hook-dir=/usr/share/mmdebstrap/hooks/busybox
Example 3: Setup merged-/usr using debootstrap-method which takes care of the
architecture specific symlinks
--hook-dir=/usr/share/mmdebstrap/hooks/merged-usr
Example 4: Automatically mount all directories referenced by C<file://> mirrors
Example 3: Automatically mount all directories referenced by C<file://> mirrors
into the chroot
--hook-dir=/usr/share/mmdebstrap/hooks/file-mirror-automount
@ -7095,6 +7075,33 @@ I<--merged-usr> and I<--no-merged-usr>
=back
=head1 MERGED-/USR
B<mmdebstrap> will create a merged-/usr chroot or not depending on whether
packages setting up merged-/usr (i.e. the B<usrmerge> package) are installed or
not. In Debian, the essential package B<init-system-helpers> is will depend
on the B<usrmerge> package, starting with Debian 12 (Bookworm).
Before Debian 12 (Bookworm), to force B<mmdebstrap> to create a chroot with
merged-/usr using symlinks, either explicitly install the B<usrmerge> package:
--include=usrmerge
or setup merged-/usr using the debootstrap-method which takes care of the
architecture specific symlinks and installs the B<usr-is-merged> package.
--hook-dir=/usr/share/mmdebstrap/hooks/merged-usr
To force B<mmdebstrap> to create a chroot without merged-/usr even after the
Debian 12 (Bookworm) release, you can use the following hook:
--hook-dir=/usr/share/mmdebstrap/hooks/no-merged-usr
This will write "this system will not be supported in the future" into
F</etc/unsupported-skip-usrmerge-conversion> inside the chroot and install the
B<usr-is-merged> package to avoid the installation of the B<usrmerge> package
and its dependencies.
=head1 COMPRESSION
B<mmdebstrap> will choose a suitable compressor for the output tarball

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@ -8,7 +8,7 @@ if [ ! -e /mmdebstrap-testenv ]; then
fi
sysctl -w kernel.unprivileged_userns_clone=1
adduser --gecos user --disabled-password user
runuser -u user -- {{ CMD }} --variant=custom --mode=unshare --setup-hook='env container=lxc debootstrap --no-merged-usr unstable "$1" {{ MIRROR }}' - /tmp/debian-mm.tar {{ MIRROR }}
runuser -u user -- {{ CMD }} --variant=custom --mode=unshare --setup-hook='env container=lxc debootstrap unstable "$1" {{ MIRROR }}' - /tmp/debian-mm.tar {{ MIRROR }}
mkdir /tmp/debian-mm
tar --xattrs --xattrs-include='*' -C /tmp/debian-mm -xf /tmp/debian-mm.tar

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@ -12,6 +12,7 @@ echo "SOURCE_DATE_EPOCH=$SOURCE_DATE_EPOCH"
# we cannot use useradd because passwd is not Essential:yes
{{ CMD }} --variant={{ VARIANT }} --mode={{ MODE }} \
--essential-hook='if [ {{ VARIANT }} = - ]; then echo _apt:*:100:65534::/nonexistent:/usr/sbin/nologin >> "$1"/etc/passwd; fi' \
$(case {{ DIST }} in oldstable|stable) : ;; *) echo --hook-dir=./hooks/merged-usr ;; esac) \
{{ DIST }} /tmp/debian-{{ DIST }}-mm.tar {{ MIRROR }}
mkdir /tmp/debian-{{ DIST }}-mm

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@ -3,6 +3,7 @@ set -eu
export LC_ALL=C.UTF-8
trap "rm -rf /tmp/debian-chroot" EXIT INT TERM
{{ CMD }} --mode=root --variant=apt \
--essential-hook=./hooks/merged-usr/essential00.sh \
--setup-hook=./hooks/merged-usr/setup00.sh \
--customize-hook='[ -L "$1"/bin -a -L "$1"/sbin -a -L "$1"/lib ]' \
{{ DIST }} /tmp/debian-chroot {{ MIRROR }}
@ -40,4 +41,10 @@ tar -C /tmp/debian-chroot --one-file-system -c . | tar -t | sort > tar2.txt
echo ./usr/lib32/;
;;
esac
echo ./usr/share/doc/usr-is-merged/
echo ./usr/share/doc/usr-is-merged/changelog.gz
echo ./usr/share/doc/usr-is-merged/copyright
echo ./var/lib/dpkg/info/usr-is-merged.list
echo ./var/lib/dpkg/info/usr-is-merged.md5sums
echo ./var/lib/dpkg/info/usr-is-merged.preinst
} | sort -u | diff -u - tar2.txt