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| author | Helmut Grohne <helmut@subdivi.de> | 2025-05-06 11:50:31 +0200 |
|---|---|---|
| committer | Helmut Grohne <helmut@subdivi.de> | 2025-05-06 11:50:31 +0200 |
| commit | 0f2f563bedd683a9271fe32b158fb978861ae4d4 (patch) | |
| tree | 38ffd18dd7e712a0a4906bec9765db038274bb7c | |
| parent | 3affb25556fde51cf8574e51fbaa6ee025549c33 (diff) | |
| download | debvm-0f2f563bedd683a9271fe32b158fb978861ae4d4.tar.gz | |
debvm-create: fix network during mmdebstrap for old releases
We primarily run the systemd network stack inside debvm and that comes
with turning /etc/resolv.conf into a symbolic link. Unfortunately, we
may break networking during VM construction that way. The behavior is
quite release dependent.
For trixie and later, systemd-resolved.postinst takes a copy of
/etc/resolv.conf and places it at the symlink target.
For bookworm, systemd-resolved.postinst overwrites /etc/resolv.conf with
a link that becomes dead.
For bullseye and earlier, customize-resolved.conf overwrites
/etc/resolv.conf with a link that becomes dead.
That being dead means that passing any further customize hooks will not
be able to utilize networking as DNS resolution fails. To improve the
user experience, customize-resolved.sh will now turn ensure that those
symlink targets are reasonably popoulated.
| -rwxr-xr-x | share/customize-resolved.sh | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/share/customize-resolved.sh b/share/customize-resolved.sh index 8885d18..ee9d0c3 100755 --- a/share/customize-resolved.sh +++ b/share/customize-resolved.sh @@ -11,6 +11,14 @@ TARGET=$1 LIBNSS_RESOLVE_VERSION=$(dpkg-query --root "$TARGET" -f '${Version}' -W libnss-resolve 2>/dev/null) || : +link_resolv_conf() { + if ! test -e "$TARGET$1" -o -h "$TARGET/etc/resolv.conf"; then + # To avoid breaking network during mmdebstrap via a dead link, take a copy. + install -D "$TARGET/etc/resolv.conf" "$TARGET$1" + fi + ln -fs "..$1" "$TARGET/etc/resolv.conf" +} + if dpkg --compare-versions "$LIBNSS_RESOLVE_VERSION" lt 251.3-2~exp1; then if test "${MMDEBSTRAP_MODE:-}" = chrootless; then systemctl --root "$TARGET" enable systemd-resolved.service @@ -19,8 +27,19 @@ if dpkg --compare-versions "$LIBNSS_RESOLVE_VERSION" lt 251.3-2~exp1; then fi if test -z "$LIBNSS_RESOLVE_VERSION" || dpkg --compare-versions "$LIBNSS_RESOLVE_VERSION" lt 236; then - ln -fs ../run/systemd/resolve/resolv.conf "$TARGET/etc/resolv.conf" + link_resolv_conf /run/systemd/resolve/resolv.conf else - ln -fs ../run/systemd/resolve/stub-resolv.conf "$TARGET/etc/resolv.conf" + link_resolv_conf /run/systemd/resolve/stub-resolv.conf + fi +else + if test -h "$TARGET/etc/resolv.conf" && ! test -e "$TARGET/etc/resolv.conf"; then + resolvconftarget=$(readlink "$TARGET/etc/resolv.conf") + if test "${resolvconftarget#../run/}" != "$resolvconftarget"; then + # /etc/resolv.conf is a dead link pointing to ../run/* + # mmdebstrap originally copied /etc/resolv.conf + # This situation arises when installing systemd-resolved in bookworm + # Fix network during mmdebstrap. + install -D /etc/resolv.conf "$TARGET${resolvconftarget#..}" + fi fi fi |