skeleton-init-systemd: Work around for RO root /var/lib not populating

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  • skeleton-init-systemd: Work around for RO root /var/lib not populating
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Trent Piepho Feb. 27, 2018, 10:16 p.m.
When using a RO root with systemd, it is intended that /var/lib should be
populated at boot time by tmpfiles system mirroring it from

However, this will only happen if /var/lib does not already exist at the
time systemd-tmpfiles runs.  If it does exist, then tmpfiles will
(silently) skip it and do nothing.

It turns out /var/lib will exist, because some part of systemd creates
/var/lib/systemd/catalog on boot before tmpfiles runs.

The fix used here is to also create tmpfiles entries for the contents of
/var/lib/* and /var/lib/systemd/*.  This way, when those directories
already exist, the entire tree is not skipped and instead the
not-yet-existing contents of /var/lib and /var/lib/systemd will be still
be mirrored from the factory dir.

And if /var/lib/systemd, or a prefix of that, stops getting created and
does not exist, it'll still mirror properly.

It does cause some warnings from systemd:
systemd[1]: Starting Create Volatile Files and Directories...
systemd-tmpfiles[148]: [/etc/tmpfiles.d/var-factory.conf:7] Duplicate line for path "/var/lib/systemd", ignoring.
systemd-tmpfiles[148]: [/etc/tmpfiles.d/var-factory.conf:8] Duplicate line for path "/var/lib/systemd/coredump", ignoring.

But they can be ignored.

IMHO, I think a better solution would be for systemd-tmpfiles to gain a
"merge tree" operation that is like "C" but doesn't abort if the
destination exists, but rather merges the source into it.

Signed-off-by: Trent Piepho <>
 package/skeleton-init-systemd/ | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)


diff --git a/package/skeleton-init-systemd/ b/package/skeleton-init-systemd/
index 93bff9d27b..0ff3c774ba 100644
--- a/package/skeleton-init-systemd/
+++ b/package/skeleton-init-systemd/
@@ -42,7 +42,10 @@  endef
 	rm -f $(TARGET_DIR)/var
 	mkdir $(TARGET_DIR)/var
-	for i in $(TARGET_DIR)/usr/share/factory/var/*; do \
+	for i in $(TARGET_DIR)/usr/share/factory/var/* \
+		 $(TARGET_DIR)/usr/share/factory/var/lib/* \
+		 $(TARGET_DIR)/usr/share/factory/var/lib/systemd/*; do \
+		[ -e "$${i}" ] || continue; \
 		j="$${i#$(TARGET_DIR)/usr/share/factory}"; \
 		if [ -L "$${i}" ]; then \
 			printf "L+! %s - - - - %s\n" \