[Buildroot] [PATCH 3/4] Makefile: check rootfs overlays with BR2_ROOTFS_MERGED_USR enabled
Carlos Santos
casantos at datacom.ind.br
Sun May 6 21:31:15 UTC 2018
Since commit 0db34529f48 we use rsync with the --keep-dirlinks option to
prevent overlays from accidentally overwriding /{usr,bin,sbin,lib} links
when BR2_ROOTFS_MERGED_USR option is enabled. Unfortunately this also
prevents replacing a symlink by a directory on purpose (e.g. /var/log,
to persist system logs).
Steps to reproduce:
- enable BR2_ROOTFS_MERGED_USR and BR2_PACKAGE_SKELETON_INIT_SYSV
- mkdir some_path/rootfs-overlay/var/log
- enable BR2_ROOTFS_OVERLAY="some_path/rootfs-overlay"
- run 'make'
- 'target/var/log' is still a symlink to '../tmp', not a directory
Fix the problem by adding a step in target-finalize that checks each
overlay, using the same criteria used in skeleton-custom.mk.
Add a paragraph to the documentation clarifying that rootfs overlays
should not contain /bin, /lib or /sbin.
Signed-off-by: Carlos Santos <casantos at datacom.ind.br>
---
Makefile | 20 +++++++++++++++++---
docs/manual/customize-rootfs.txt | 5 +++++
2 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/Makefile b/Makefile
index c024c65f78..dc51269143 100644
--- a/Makefile
+++ b/Makefile
@@ -746,11 +746,25 @@ endif
@$(call MESSAGE,"Sanitizing RPATH in target tree")
$(TOPDIR)/support/scripts/fix-rpath target
+# For a merged /usr, ensure that /lib, /bin and /sbin and their /usr
+# counterparts are appropriately setup as symlinks ones to the others.
+ifeq ($(BR2_ROOTFS_MERGED_USR),y)
+
+ @$(foreach d, $(call qstrip,$(BR2_ROOTFS_OVERLAY)), \
+ $(call MESSAGE,"Sanity check in overlay $(d)"); \
+ not_merged_dirs="$$(support/scripts/check-merged-usr.sh $(d))"; \
+ test -n "$$not_merged_dirs" && { \
+ echo "ERROR: The overlay in $(d) is not" \
+ "using a merged /usr for the following directories:" \
+ $$not_merged_dirs; \
+ exit 1; \
+ } || true$(sep))
+
+endif # merged /usr
+
@$(foreach d, $(call qstrip,$(BR2_ROOTFS_OVERLAY)), \
$(call MESSAGE,"Copying overlay $(d)"); \
- rsync -a --ignore-times --keep-dirlinks $(RSYNC_VCS_EXCLUSIONS) \
- --chmod=u=rwX,go=rX --exclude .empty --exclude '*~' \
- $(d)/ $(TARGET_DIR)$(sep))
+ $(call SYSTEM_RSYNC,$(d),$(TARGET_DIR))$(sep))
@$(foreach s, $(call qstrip,$(BR2_ROOTFS_POST_BUILD_SCRIPT)), \
$(call MESSAGE,"Executing post-build script $(s)"); \
diff --git a/docs/manual/customize-rootfs.txt b/docs/manual/customize-rootfs.txt
index 8982e03498..5dbbe86044 100644
--- a/docs/manual/customize-rootfs.txt
+++ b/docs/manual/customize-rootfs.txt
@@ -22,6 +22,11 @@ A filesystem overlay is a tree of files that is copied directly
etc., files called +.empty+ and files ending in +~+ are excluded from
the copy.
+
+Overlays should not contain the '/bin', '/lib' or '/sbin' paths, since
+ they are created during the build, either as directories or as
+ symbolic links to their counterparts under 'usr', depending on the
+ system configuration.
++
As shown in xref:customize-dir-structure[], the recommended path for
this overlay is +board/<company>/<boardname>/rootfs-overlay+.
--
2.17.0
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