[Buildroot] [PATCH v2 11/18] package/pkg-generic.mk: generate final rsync exclude file list

[Herve Codina]

The final rsync performed at {host,target}-finalize steps
need to be done by rsyncing files generated by each packages
without looking at files generated by other packages the current
package depends on. This is needed to avoid overwrites in final
{HOST,TARGET}_DIR.

In order to prepare the final rsync, an exclusion list is generated.
This list lists files that are not generated by the current package and
so files that need to be excluded from the final rsync.

Note also that the files list was not based on .files-list.{before,after}.
During .file-list.{before,after} built for host directory, staging
sub-directory (ie <toolchain>/sysroot) is filtered out.
The final rsync exclusion list needs to take into account the full
{host,target} directory to avoid final overwrites.

Using an empty directory for per-package installation directory would be the
simplest way to find what a package installs.
However, as it has been discussed in the past, this is fraught with unworkable
issues. For example, some paths may be hard-coded at configure time and/or build
time, and thus the package would still install in the original stagin we presented
it with (for target/, this is not an isue, because target/ is never looked at
during configure or build, only at install time). Or a package installation
process just assumes that the directory structure exists (bad, but eh...).

Signed-off-by: Herve Codina <herve.codina at bootlin.com>
---
Changes v1 to v2:
 - Added a note in the commit message related to why an empty directory is not
   used to find what a package installs.

 package/pkg-generic.mk | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/package/pkg-generic.mk b/package/pkg-generic.mk
index 3e1030a495..6157f6e540 100644
--- a/package/pkg-generic.mk
+++ b/package/pkg-generic.mk
@@ -162,6 +162,30 @@ define pkg_size_after
 	rm -f $($(PKG)_DIR)/.files-list$(2).after
 endef
 
+# Functions to collect final rsync exclusion files
+
+# $(1): base directory to search in
+# $(2): suffix of file (optional)
+define pkg_final_rsync_before
+	cd $(1); \
+	LC_ALL=C find . \( -type f -o -type l \) -printf '%T@:%i:%#m:%y:%s,%p\n' \
+		| LC_ALL=C sort > $($(PKG)_DIR)/.files-final-rsync$(2).before
+endef
+
+# $(1): base directory to search in
+# $(2): suffix of file (optional)
+define pkg_final_rsync_after
+	cd $(1); \
+	LC_ALL=C find . \( -type f -o -type l \) -printf '%T@:%i:%#m:%y:%s,%p\n' \
+		| LC_ALL=C sort > $($(PKG)_DIR)/.files-final-rsync$(2).after
+	LC_ALL=C comm -2 \
+		$($(PKG)_DIR)/.files-final-rsync$(2).before \
+		$($(PKG)_DIR)/.files-final-rsync$(2).after \
+		| sed -r -e 's/^[^,]+,./- /' \
+		> $($(PKG)_DIR)/.files-final-rsync$(2).exclude_rsync
+	rm -f $($(PKG)_DIR)/.files-final-rsync$(2).after
+endef
+
 define check_bin_arch
 	support/scripts/check-bin-arch -p $($(PKG)_NAME) \
 		-l $($(PKG)_DIR)/.files-list.txt \
@@ -283,6 +307,8 @@ $(BUILD_DIR)/%/.stamp_configured:
 	@$(call MESSAGE,"Configuring")
 	$(Q)mkdir -p $(HOST_DIR) $(TARGET_DIR) $(STAGING_DIR) $(BINARIES_DIR)
 	$(call prepare-per-package-directory,$($(PKG)_FINAL_DEPENDENCIES))
+	@$(call pkg_final_rsync_before,$(TARGET_DIR))
+	@$(call pkg_final_rsync_before,$(HOST_DIR),-host)
 	@$(call pkg_size_before,$(TARGET_DIR))
 	@$(call pkg_size_before,$(STAGING_DIR),-staging)
 	@$(call pkg_size_before,$(HOST_DIR),-host)
@@ -417,6 +443,8 @@ $(BUILD_DIR)/%/.stamp_installed:
 	@$(call pkg_size_after,$(STAGING_DIR),-staging)
 	@$(call pkg_size_after,$(HOST_DIR),-host)
 	@$(call check_bin_arch)
+	@$(call pkg_final_rsync_after,$(TARGET_DIR))
+	@$(call pkg_final_rsync_after,$(HOST_DIR),-host)
 	@$(call pkg_detect_overwrite_after,$(TARGET_DIR))
 	@$(call pkg_detect_overwrite_after,$(HOST_DIR),-host)
 	$(Q)touch $@
-- 
2.31.1