io.c: fix IO.copy_stream on O_APPEND destination on Linux

Linux copy_file_range(2) fails with EBADF if the destination FD
has O_APPEND set.  Preserve existing (Ruby <= 2.4) behavior by
falling back to alternative copy mechanisms if this is the case
(instead of raising Errno::EBADF).

* io.c (nogvl_copy_file_range): do not raise on O_APPEND dst
* test/ruby/test_io.rb (test_copy_stream_append): new test
  [Feature #13867]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60490 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 10 insertions, 0 deletions

diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index b5d69d9ba4..7f86b4ebaf 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -366,6 +366,16 @@ class TestIO < Test::Unit::TestCase
     }
   end
 
+  def test_copy_stream_append
+    with_srccontent("foobar") {|src, content|
+      File.open('dst', 'ab') do |dst|
+        ret = IO.copy_stream(src, dst)
+        assert_equal(content.bytesize, ret)
+        assert_equal(content, File.read("dst"))
+      end
+    }
+  end
+
   def test_copy_stream_smaller
     with_srccontent {|src, content|