[Buildroot] [PATCH 1/3] systemd: Ensure /run and /var/run are the same on R/O rootfs

[Yann E. MORIN]

Jan, All,

On 2018-02-08 12:22 +0100, Jan Kundrát spake thusly:
> When I updated systemd from 234 to 237 and D-Bus from 1.12.0 to 1.12.2
> on my system with a read-only rootfs (buildroot 1c0c55c028 to buildroot
> 27d2229692), my D-Bus-activated services stopped working. Checking the
> logs, it turned out that systemd PID 1 was not able to connect the D-Bus
> socket at all. There were some recent changes in systemd where upstream
> refactored code which waits for sockets to appear. However, the real
> problem is that systemd is configured to look for the D-Bus socket in
> /run/dbus, while D-Bus creates it at /var/run/dbus/. D-Bus upstream
> explains in a bugreport [1] that this "traditional" /var/run/dbus is
> going to stay because it's hardcoded in other independent
> implementations of the D-Bus APIs.
> 
> As is also said in that bugreport, the root cause is that /run and
> /var/run are effectively two separate directories on Buildroot -- at
> least when configured for a R/O rootfs. Furthermore, systemd actually
> actively warns about this:
> 
>   systemd[1]: System is tainted: var-run-bad
> 
> Looking further, systemd-tmpfiles also detects breakage:
> 
>   systemd-tmpfiles[172]: [/usr/lib/tmpfiles.d/var.conf:12] Duplicate line for path "/var/run", ignoring.
>   systemd-tmpfiles[172]: [/usr/lib/tmpfiles.d/var.conf:14] Duplicate line for path "/var/log", ignoring.
>   systemd-tmpfiles[172]: [/usr/lib/tmpfiles.d/var.conf:21] Duplicate line for path "/var/lib", ignoring.
> 
> This change simply skips /var/run from being copied from the
> /usr/share/factory. The symlink is still created by another tmpfiles.d
> entry which belongs to systemd.

We believe this issue has been fixed in antoher way with that patch:

    6e5df928539 package/skeleton-systemd: invert factory logic

As thus, I've marked this patch as rejected.

If your use-case is still not fixed, please re-send it.

Thanks!

Regards,
Yann E. MORIN.

> The other warnings are still in present:
> 
>   systemd-tmpfiles[174]: [/usr/lib/tmpfiles.d/var.conf:14] Duplicate line for path "/var/log", ignoring.
>   systemd-tmpfiles[174]: [/usr/lib/tmpfiles.d/var.conf:21] Duplicate line for path "/var/lib", ignoring.
> 
> I'm leaving that one to someone who is more familiar with systemd and
> buildroot conventions. My box now boots again, so I'm happy :).
> 
> [1] https://bugs.freedesktop.org/show_bug.cgi?id=101628
> 
> Signed-off-by: Jan Kundrát <jan.kundrat at cesnet.cz>
> ---
>  package/skeleton-init-systemd/skeleton-init-systemd.mk | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/package/skeleton-init-systemd/skeleton-init-systemd.mk b/package/skeleton-init-systemd/skeleton-init-systemd.mk
> index a2d4e8c4b3..95142904f5 100644
> --- a/package/skeleton-init-systemd/skeleton-init-systemd.mk
> +++ b/package/skeleton-init-systemd/skeleton-init-systemd.mk
> @@ -42,7 +42,9 @@ define SKELETON_INIT_SYSTEMD_PRE_ROOTFS_VAR
>  	mkdir $(TARGET_DIR)/var
>  	for i in $(TARGET_DIR)/usr/share/factory/var/*; do \
>  		j="$${i#$(TARGET_DIR)/usr/share/factory}"; \
> -		if [ -L "$${i}" ]; then \
> +		if [ "$${j}" = "/var/run" ]; then \
> +			echo "# $${j} is being handled by systemd"
> +		elif [ -L "$${i}" ]; then \
>  			printf "L+! %s - - - - %s\n" \
>  				"$${j}" "../usr/share/factory/$${j}" \
>  			|| exit 1; \
> -- 
> 2.14.3
> 
> 
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