Re: [PATCH] framework for building modules externally

[Robert Millan <rmh@aybabtu.com>]

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On Sat, Nov 01, 2008 at 01:32:29PM +0100, Robert Millan wrote:
> 
> Hi,
> 
> Attached patch makes it possible to build modules externally, by:
> 
>   - Installing headers in system include dir.
> 
>   - Exporting two ABI tags (a build-time macro and a run-time variable)
>     for run-time comparison.
> 
>   - Exporting a makefile with COMMON_*FLAGS variables.

Looks like I missed some important details.  The headers and some macros are
not enough, as we need to reproduce part of the build system to build a module
externally.  This new patch provides the following:

  In pkgdata:	genmodsrc.sh genmk.rb
  In pkglib:	config.h grub_script.tab.h build_env.mk
  In includedir:	header files

How to use:

cat > Makefile.in << EOF
srcdir = /usr/share/grub
builddir = /usr/lib/grub/i386-pc
include $(builddir)/build_env.mk

pkglib_MODULES += mymod.mod
mymod_mod_SOURCES = mymod.c
mymod_mod_CFLAGS = $(COMMON_CFLAGS)
mymod_mod_LDFLAGS = $(COMMON_LDFLAGS)
EOF
ruby /usr/share/grub/genmk.rb < Makefile.in > Makefile
make

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."

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2008-11-01  Robert Millan  <rmh@aybabtu.com>

	* Makefile.in (PKGLIB): Add $(pkglib_BUILDDIR).
	(PKGDATA): Add $(pkgdata_SRCDIR).
	(pkglib_BUILDDIR): New variable.
	(pkgdata_SRCDIR): New variable.
	(build_env.mk): New target.
	(include_DATA): New variable.
	(install-local): Install $(include_DATA) files in $(includedir).

	* include/grub/misc.h (GRUB_ABI): New macro (initialize as 0).
	(grub_abi): New variable prototype.
	* kern/main.c (grub_abi): New variable (initialize as GRUB_ABI).

Index: Makefile.in
===================================================================
--- Makefile.in	(revision 1891)
+++ Makefile.in	(working copy)
@@ -105,8 +105,8 @@
 MKFILES = $(patsubst %.rmk,%.mk,$(RMKFILES))
 
 PKGLIB = $(pkglib_IMAGES) $(pkglib_MODULES) $(pkglib_PROGRAMS) \
-	$(pkglib_DATA) $(lib_DATA)
-PKGDATA = $(pkgdata_DATA)
+	$(pkglib_DATA) $(lib_DATA) $(pkglib_BUILDDIR)
+PKGDATA = $(pkgdata_DATA) $(pkgdata_SRCDIR)
 PROGRAMS = $(bin_UTILITIES) $(sbin_UTILITIES)
 SCRIPTS = $(bin_SCRIPTS) $(sbin_SCRIPTS) $(grub-mkconfig_SCRIPTS)
 
@@ -163,6 +163,22 @@
 	ruby $(srcdir)/util/unifont2pff.rb 0x0-0x7f $(UNICODE_ARROWS) $(UNICODE_LINES) $(UNIFONT_HEX) > $@
 endif
 
+# Used for building modules externally
+pkglib_BUILDDIR += build_env.mk
+build_env.mk: Makefile
+	(\
+	echo "TARGET_CC=$(TARGET_CC)" ; \
+	echo "TARGET_CFLAGS=$(TARGET_CFLAGS)" ; \
+	echo "TARGET_CPPFLAGS=$(TARGET_CPPFLAGS) -I$(pkglibdir)" ; \
+	echo "STRIP=$(STRIP)" ; \
+	echo "COMMON_ASFLAGS=$(COMMON_ASFLAGS)" ; \
+	echo "COMMON_CFLAGS=$(COMMON_CFLAGS)" ; \
+	echo "COMMON_LDFLAGS=$(COMMON_LDFLAGS)"\
+	) > $@
+pkglib_BUILDDIR += config.h grub_script.tab.h
+pkgdata_SRCDIR += genmodsrc.sh genmk.rb
+include_DATA += $(shell find include -name \*.h) include/grub/cpu
+
 all-local: $(PROGRAMS) $(PKGLIB) $(PKGDATA) $(SCRIPTS) $(MKFILES)
 
 install: install-local
@@ -175,6 +191,19 @@
 	  dest="`echo $$file | sed 's,.*/,,'`"; \
 	  $(INSTALL_DATA) $$dir$$file $(DESTDIR)$(pkglibdir)/$$dest; \
 	done
+	$(mkinstalldirs) $(DESTDIR)$(includedir)
+	@list='$(include_DATA)'; \
+	for file in $$list; do \
+	  if test -f "$$file"; then dir=; else dir="$(srcdir)/"; fi; \
+	  dest="`echo $$file | sed 's,include/,,'`"; \
+	  destdir="`echo $$dest | sed 's,\(^\|/\)[^/]*$$,,g'`"; \
+	  $(mkinstalldirs) $(DESTDIR)$(includedir)/$$destdir; \
+	  if test -f "$$dir$$file"; then \
+	    $(INSTALL_DATA) $$dir$$file $(DESTDIR)$(includedir)/$$dest; \
+	  elif test -L "$$dir$$file"; then \
+	    cp -d $$dir$$file $(DESTDIR)$(includedir)/$$dest; \
+	  fi; \
+	done
 	$(mkinstalldirs) $(DESTDIR)$(pkgdatadir)
 	@list='$(PKGDATA)'; \
 	for file in $$list; do \
Index: kern/main.c
===================================================================
--- kern/main.c	(revision 1891)
+++ kern/main.c	(working copy)
@@ -28,6 +28,8 @@
 #include <grub/env.h>
 #include <grub/mm.h>
 
+grub_uint32_t grub_abi = GRUB_ABI;
+
 void
 grub_module_iterate (int (*hook) (struct grub_module_header *header))
 {
Index: include/grub/misc.h
===================================================================
--- include/grub/misc.h	(revision 1891)
+++ include/grub/misc.h	(working copy)
@@ -25,6 +25,10 @@
 #include <grub/symbol.h>
 #include <grub/err.h>
 
+/* Increase this number every time GRUB ABI is changed.  */
+#define GRUB_ABI	0
+extern grub_uint32_t EXPORT_VAR(grub_abi);
+
 #define ALIGN_UP(addr, align) (((grub_uint64_t)addr + align - 1) & ~(align - 1))
 
 #define grub_dprintf(condition, fmt, args...) grub_real_dprintf(__FILE__, __LINE__, condition, fmt, ## args);