From 1ca30e35b01a8d6444c92475b0a95041df1d258b Mon Sep 17 00:00:00 2001
From: John Johansen <john.johansen@canonical.com>
Date: Wed, 26 Jan 2022 08:04:04 -0800
Subject: [PATCH] libapparmor: Fix ruby 3.1 build for libapparmor

The Hack used to build the libapparmor swig interface for ruby fails
with ruby 3.1.  Instead of trying to do black magic in ruby to rename
the generated Makefile to Makefile.new, just save off the Makefile
and restore after ruby's setup has been called.

Fixes: https://gitlab.com/apparmor/apparmor/-/issues/206
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Christian Boltz <apparmor@cboltz.de>
---
 .gitignore                                  |  2 +-
 libraries/libapparmor/swig/ruby/Makefile.am |  4 +++-
 libraries/libapparmor/swig/ruby/extconf.rb  | 14 +++-----------
 3 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/.gitignore b/.gitignore
index 4782a351a..bac706f2b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -177,7 +177,7 @@ libraries/libapparmor/swig/ruby/LibAppArmor_wrap.c
 libraries/libapparmor/swig/ruby/LibAppArmor_wrap.o
 libraries/libapparmor/swig/ruby/Makefile
 libraries/libapparmor/swig/ruby/Makefile.in
-libraries/libapparmor/swig/ruby/Makefile.new
+libraries/libapparmor/swig/ruby/Makefile.bak
 libraries/libapparmor/swig/ruby/Makefile.ruby
 libraries/libapparmor/swig/ruby/mkmf.log
 libraries/libapparmor/testsuite/.deps
diff --git a/libraries/libapparmor/swig/ruby/Makefile.am b/libraries/libapparmor/swig/ruby/Makefile.am
index 03ef02fd6..465fa7463 100644
--- a/libraries/libapparmor/swig/ruby/Makefile.am
+++ b/libraries/libapparmor/swig/ruby/Makefile.am
@@ -9,7 +9,9 @@ LibAppArmor_wrap.c : $(srcdir)/../SWIG/libapparmor.i
 MOSTLYCLEANFILES=LibAppArmor_wrap.c
 
 Makefile.ruby: extconf.rb
+	mv Makefile Makefile.bak
 	PREFIX=$(prefix) $(RUBY) $< --with-LibAppArmor-include=$(top_srcdir)/include
+	mv Makefile.bak Makefile
 
 LibAppArmor.so: LibAppArmor_wrap.c Makefile.ruby
 	$(MAKE) -fMakefile.ruby
@@ -22,7 +24,7 @@ install-exec-local: Makefile.ruby
 
 clean-local:
 	if test -f Makefile.ruby; then $(MAKE) -fMakefile.ruby clean; fi
-	rm -f Makefile.ruby Makefile.new
+	rm -f Makefile.ruby Makefile.bak
 	rm -f *.o *.so *.log
 
 endif
diff --git a/libraries/libapparmor/swig/ruby/extconf.rb b/libraries/libapparmor/swig/ruby/extconf.rb
index 647d2d831..6a2ef7457 100644
--- a/libraries/libapparmor/swig/ruby/extconf.rb
+++ b/libraries/libapparmor/swig/ruby/extconf.rb
@@ -2,16 +2,8 @@
 
 require 'mkmf'
 
-# hack 1: ruby black magic to write a Makefile.new instead of a Makefile
-alias open_orig open
-def open(path, mode=nil, perm=nil)
-  path = 'Makefile.new' if path == 'Makefile'
-  if block_given?
-    open_orig(path, mode, perm) { |io| yield(io) }
-  else
-    open_orig(path, mode, perm)
-  end
-end
+# hack 1: Before extconf.rb gets called, Makefile gets backed up, and
+#         restored afterwards (see Makefile.am)
 
 if ENV['PREFIX']
   prefix = CONFIG['prefix']
@@ -27,7 +19,7 @@ if find_library('apparmor', 'parse_record', '../../src/.libs') and
 
   # hack 2: strip all rpath references
   open('Makefile.ruby', 'w') do |out|
-    IO.foreach('Makefile.new') do |line|
+    IO.foreach('Makefile') do |line|
       out.puts line.gsub(/-Wl,-R'[^']*'/, '')
     end
   end