Makefile: add 'show-info-all'

The maintenance and testing workflow sometimes requires to output a
list of every existing package on Buildroot:

- Generating an SBOM of the whole Buildroot tree, e.g. `for
  security.buildroot.org
- List every source for every package, e.g. for sources.buildroot.net

The previous solution relied on `make allyesconfig` but always ran into
conflicts that needed manual resolution. Also some packages would not be
present because they are architecture dependent.

To avoid having to manually modify the 'show-info' command this commit
adds the 'show-info-all' command. It accesses the PACKAGES_ALL variable
with all the packages present in Buildroot independently of the
architecture or any config entries.

It forces the `BR2_HAVE_DOT_CONFIG` variable to be set to force the
reading of the package mk files.

It is also added to noconfig_targets, to avoid the .config influencing
the output of show-info-all.

Note that this is not yet a complete solution - it doesn't take into
account the multiple versions that are possible for some packages like
GCC. Also for e.g. linux or uboot the version is empty and the URL is
invalid.

Signed-off-by: Thomas Perale <thomas.perale@mind.be>
[Arnout: refactor with existing show-info]
Signed-off-by: Arnout Vandecappelle <arnout@rnout.be>
(cherry picked from commit 723b321bb0)
Signed-off-by: Thomas Perale <thomas.perale@mind.be>

Makefile

@@ -126,7 +126,7 @@ noconfig_targets := menuconfig nconfig gconfig xconfig config oldconfig randconf
 	defconfig %_defconfig allyesconfig allnoconfig alldefconfig syncconfig release \
 	randpackageconfig allyespackageconfig allnopackageconfig \
 	print-version olddefconfig distclean manual manual-% check-package \
-	check-package-external
+	check-package-external show-info-all
 
 # Some global targets do not trigger a build, but are used to collect
 # metadata, or do various checks. When such targets are triggered,
@@ -142,7 +142,7 @@ nobuild_targets := source %-source \
 	clean distclean help show-targets graph-depends \
 	%-graph-depends %-show-depends %-show-version \
 	graph-build graph-size list-defconfigs \
-	savedefconfig update-defconfig printvars show-vars
+	savedefconfig update-defconfig printvars show-vars show-info-all
 ifeq ($(MAKECMDGOALS),)
 BR_BUILDING = y
 else ifneq ($(filter-out $(nobuild_targets),$(MAKECMDGOALS)),)
@@ -236,6 +236,13 @@ BR2_CONFIG = $(CONFIG_DIR)/.config
 ifeq ($(filter $(noconfig_targets),$(MAKECMDGOALS)),)
 -include $(BR2_CONFIG)
 endif
+# show-info-all needs to access the PACKAGES_ALL variable. This variable
+# contains a reference to every package present in Buildroot.
+# Since the 'show-info-all' command might be used without actually having a
+# dotconfig this condition is forced to be set true.
+ifeq ($(MAKECMDGOALS),show-info-all)
+BR2_HAVE_DOT_CONFIG = y
+endif
 
 ifeq ($(BR2_PER_PACKAGE_DIRECTORIES),)
 # Disable top-level parallel build if per-package directories is not
@@ -934,15 +941,22 @@ check-dependencies:
 	$(TOPDIR)/support/scripts/graph-depends -C
 
 .PHONY: show-info
-show-info:
+show-info: show-info-inner
+show-info: SHOW_INFO_PACKAGES = \
+	$(foreach i,$(PACKAGES) $(TARGETS_ROOTFS), \
+		$(i) $($(call UPPERCASE,$(i))_FINAL_RECURSIVE_DEPENDENCIES) \
+	)
+
+.PHONY: show-info-all
+show-info-all: show-info-inner
+show-info-all: SHOW_INFO_PACKAGES = $(PACKAGES_ALL)
+
+.PHONY: show-info-inner
+show-info-inner:
 	@:
 	$(info $(call clean-json, \
 			{ $(foreach p, \
-				$(sort $(foreach i,$(PACKAGES) $(TARGETS_ROOTFS), \
-						$(i) \
-						$($(call UPPERCASE,$(i))_FINAL_RECURSIVE_DEPENDENCIES) \
-					) \
-				), \
+				$(sort $(SHOW_INFO_PACKAGES)), \
 				$(call json-info,$(call UPPERCASE,$(p)))$(comma) \
 			) } \
 		) \
@@ -1213,6 +1227,8 @@ help:
 	@echo '  external-deps          - list external packages used'
 	@echo '  legal-info             - generate info about license compliance'
 	@echo '  show-info              - generate info about packages, as a JSON blurb'
+	@echo '  show-info-all          - generate info about all packages in Buildroot,'
+	@echo '                           regardless of configuration or target architecture'
 	@echo '  pkg-stats              - generate info about packages as JSON and HTML'
 	@echo '  printvars              - dump internal variables selected with VARS=...'
 	@echo '  show-vars              - dump all internal variables as a JSON blurb; use VARS=...'

docs/manual/common-usage.adoc

@@ -170,6 +170,18 @@ by using the +show-info+ make target:
 make show-info
 ----
 
+Buildroot can also produce information in the +show-info+ format about all
+packages regardless of the configuration or architecture by using
++show-info-all+.
+This is used for maintenance tasks that require information about every
+package in the tree, such as generating a full-tree SBOM for
+https://security.buildroot.org[].
+It does not require a +.config+ file:
+
+----
+make show-info-all
+----
+
 Buildroot can also produce details about packages as HTML and JSON
 output using the +pkg-stats+ make target. Amongst other things, these
 details include whether known CVEs (security vulnerabilities) affect