package/skeleton-systemd: invert factory logic

Currently, we handle the factory by redirectoring /var with a symlink at
build time, and with some trickery during the filesystem generation,
depending on whether we need to remount the filesystem read-write or
not.

However, this is causing quite some pain with the latest systemd, now that
they have moved their dbus socket to /run instead of /var/run.

As such, trying to play tricks with /var/run as a symlink is difficult,
because at times it is in .usr/share/factory/var/run (during build) and
then it is in /var/run (at runtime). So a relative symlink is not
possible. But an absolute symlink is not possible either, because we are
installing out-of-tree.

Oh the joys of cross-compilation... :-)

We fix all this mess by making /var a real directory from the onset, so
that we can use the runtime-expected layout even during the build.

Then, during filesystem generation, we move /var away to the factory,
and populate it as we used to do. This still requires a post-fs hook to
restore /var after the filesystem generation.

This leaves a situation that, should the filesystem generation fails,
/var will be left in an inconsistent state. But that is not worse than
what we already had anyway.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Cc: Trent Piepho <tpiepho@impinj.com>
Cc: Adam Duskett <aduskett@gmail.com>
Cc: Romain Naour <romain.naour@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
This commit is contained in:
Yann E. MORIN 2018-03-04 18:06:16 +01:00 committed by Peter Korsgaard
parent 7e811708f3
commit 6e5df92853

View File

@ -19,7 +19,6 @@ ifeq ($(BR2_TARGET_GENERIC_REMOUNT_ROOTFS_RW),y)
define SKELETON_INIT_SYSTEMD_ROOT_RO_OR_RW
echo "/dev/root / auto rw 0 1" >$(TARGET_DIR)/etc/fstab
mkdir -p $(TARGET_DIR)/var
endef
else
@ -31,15 +30,14 @@ else
# back there by the tmpfiles.d mechanism.
define SKELETON_INIT_SYSTEMD_ROOT_RO_OR_RW
mkdir -p $(TARGET_DIR)/etc/systemd/tmpfiles.d
mkdir -p $(TARGET_DIR)/usr/share/factory/var
ln -s usr/share/factory/var $(TARGET_DIR)/var
echo "/dev/root / auto ro 0 1" >$(TARGET_DIR)/etc/fstab
echo "tmpfs /var tmpfs mode=1777 0 0" >>$(TARGET_DIR)/etc/fstab
endef
define SKELETON_INIT_SYSTEMD_PRE_ROOTFS_VAR
rm -f $(TARGET_DIR)/var
mkdir $(TARGET_DIR)/var
rm -rf $(TARGET_DIR)/usr/share/factory/var
mv $(TARGET_DIR)/var $(TARGET_DIR)/usr/share/factory/var
mkdir -p $(TARGET_DIR)/var
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 \
@ -59,7 +57,7 @@ SKELETON_INIT_SYSTEMD_ROOTFS_PRE_CMD_HOOKS += SKELETON_INIT_SYSTEMD_PRE_ROOTFS_V
define SKELETON_INIT_SYSTEMD_POST_ROOTFS_VAR
rm -rf $(TARGET_DIR)/var
ln -s usr/share/factory/var $(TARGET_DIR)/var
mv $(TARGET_DIR)/usr/share/factory/var $(TARGET_DIR)/var
endef
SKELETON_INIT_SYSTEMD_ROOTFS_POST_CMD_HOOKS += SKELETON_INIT_SYSTEMD_POST_ROOTFS_VAR
@ -68,6 +66,8 @@ endif
define SKELETON_INIT_SYSTEMD_INSTALL_TARGET_CMDS
mkdir -p $(TARGET_DIR)/home
mkdir -p $(TARGET_DIR)/srv
mkdir -p $(TARGET_DIR)/var
ln -s ../run $(TARGET_DIR)/var/run
$(SKELETON_INIT_SYSTEMD_ROOT_RO_OR_RW)
endef