Tidy up ld preload hacks

tests/acceptance/test_serve_mode.rb

@@ -1,9 +1,11 @@
 require 'test/unit'
 require 'environment'
 require 'flexnbd/fake_source'
-require 'tempfile'
+require 'ld_preload'
 
 class TestServeMode < Test::Unit::TestCase
+  include LdPreload
+
   def setup
     super
     @b = "\xFF".b
@@ -12,7 +14,6 @@ class TestServeMode < Test::Unit::TestCase
 
   def teardown
     @env.cleanup
-    teardown_msync_catcher
     super
   end
 
@@ -39,33 +40,10 @@ class TestServeMode < Test::Unit::TestCase
     end
   end
 
-  def setup_msync_catcher
-    `make -C ld_preloads/ msync_catcher.o`
-    omit 'LD_PRELOAD library not found' unless
-      File.exist?('ld_preloads/msync_catcher.o')
-
-    @msync_catcher = Tempfile.new('msync')
-    ENV['MSYNC_CATCHER_OUTPUT'] = @msync_catcher.path
-
-    @ld_preload_orig = ENV['LD_PRELOAD']
-    ENV['LD_PRELOAD'] = 'ld_preloads/msync_catcher.o'
-  end
-
-  def parse_msync_output
-    op = []
-    until @msync_catcher.eof?
-      op << @msync_catcher.readline.chomp.split(':').map do |e|
-        e =~ /^\d+$/ ? e.to_i : e
-      end
+  def parse_msync_logs
+    read_ld_preload_log('msync_logger').map do |l|
+      l.split(':').map { |i| i =~ /^\d+$/ ? i.to_i : i }
     end
-    op
-  end
-
-  def teardown_msync_catcher
-    @msync_catcher.close if @msync_catcher
-
-    ENV.delete 'MSYNC_CATCHER_OUTPUT'
-    ENV['LD_PRELOAD'] = @ld_preload_orig
   end
 
   def test_bad_request_magic_receives_error_response
@@ -160,39 +138,42 @@ class TestServeMode < Test::Unit::TestCase
   end
 
   def test_flush_is_accepted
-    setup_msync_catcher
-    connect_to_server do |client|
-      client.flush
-      rsp = client.read_response
-      assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
-      assert_equal 0, rsp[:error]
+    with_ld_preload('msync_logger') do
+      connect_to_server do |client|
+        client.flush
+        rsp = client.read_response
+        assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
+        assert_equal 0, rsp[:error]
+      end
+      op = parse_msync_logs
+      assert_equal 1, op.count, 'Only one msync expected'
+      assert_equal @env.blocksize, op.first[2], 'msync length wrong'
+      assert_equal 6, op.first[3], 'msync called with incorrect flags'
     end
-    op = parse_msync_output
-    assert_equal 1, op.count, 'Only one msync expected'
-    assert_equal @env.blocksize, op.first[2], 'msync length wrong'
-    assert_equal 6, op.first[3], 'msync called with incorrect flags'
   end
 
   def test_write_with_fua_is_accepted
-    setup_msync_catcher
-    page_size = Integer(`getconf PAGESIZE`)
-    @env.blocksize = page_size * 10
-    connect_to_server do |client|
-      # Write somewhere in the third page
-      pos = page_size * 3 + 100
-      client.write_with_fua(pos, "\x00" * 33)
-      rsp = client.read_response
-      assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
-      assert_equal 0, rsp[:error]
+    with_ld_preload('msync_logger') do
+      page_size = Integer(`getconf PAGESIZE`)
+
+      @env.blocksize = page_size * 10
+      connect_to_server do |client|
+        # Write somewhere in the third page
+        pos = page_size * 3 + 100
+        client.write_with_fua(pos, "\x00" * 33)
+        rsp = client.read_response
+        assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
+        assert_equal 0, rsp[:error]
+      end
+      op = parse_msync_logs
+
+      assert_equal 1, op.count, 'Only one msync expected'
+
+      # Should be 100 + 33, as we've started writing 100 bytes into a page, for
+      # 33 bytes
+      assert_equal 133, op.first[2], 'msync length wrong'
+      assert_equal 6, op.first[3], 'msync called with incorrect flags'
     end
-
-    op = parse_msync_output
-    assert_equal 1, op.count, 'Only one msync expected'
-
-    # Should be 100 + 33, as we've started writing 100 bytes into a page, for
-    # 33 bytes
-    assert_equal 133, op.first[2], 'msync length wrong'
-    assert_equal 6, op.first[3], 'msync called with incorrect flags'
   end
 
   def test_odd_size_discs_are_truncated_to_nearest_512