Add support for `sockaddr_un` on Windows. (#6513)

* Windows: Fix warning about undefined if_indextoname()

* Windows: Fix UNIXSocket on MINGW and make .pair more reliable

* Windows: Use nonblock=true for read tests with scheduler

* Windows: Move socket detection from File.socket? to File.stat

Add S_IFSOCK to Windows and interpret reparse points accordingly.
Enable tests that work now.

* Windows: Use wide-char functions to UNIXSocket

This fixes behaviour with non-ASCII characters.
It also fixes deletion of temporary UNIXSocket.pair files.

* Windows: Add UNIXSocket tests for specifics of Windows impl.

* Windows: fix VC build due to missing _snwprintf

Avoid usage of _snwprintf, since it fails linking ruby.dll like so:

  linking shared-library x64-vcruntime140-ruby320.dll
  x64-vcruntime140-ruby320.def : error LNK2001: unresolved external symbol snwprintf
  x64-vcruntime140-ruby320.def : error LNK2001: unresolved external symbol vsnwprintf_l

whereas linking miniruby.exe succeeds.

This patch uses snprintf on the UTF-8 string instead.

Also remove branch GetWindowsDirectoryW, since it doesn't work.

* Windows: Fix dangling symlink test failures

Co-authored-by: Lars Kanis <kanis@comcard.de>

3 files changed, 21 insertions, 11 deletions

diff --git a/test/ruby/test_file_exhaustive.rb b/test/ruby/test_file_exhaustive.rb
index 8cd020533b..d0472a0081 100644
--- a/test/ruby/test_file_exhaustive.rb
+++ b/test/ruby/test_file_exhaustive.rb
@@ -649,7 +649,7 @@ class TestFileExhaustive < Test::Unit::TestCase
       # ignore unsupporting filesystems
     rescue Errno::EPERM
       # Docker prohibits statx syscall by the default.
-      skip("statx(2) is prohibited by seccomp")
+      omit("statx(2) is prohibited by seccomp")
     end
     assert_raise(Errno::ENOENT) { File.birthtime(nofile) }
   end if File.respond_to?(:birthtime)
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index 6313e11179..0bf24960c6 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -900,6 +900,10 @@ class TestIO < Test::Unit::TestCase
   end if defined? UNIXSocket
 
   def test_copy_stream_socket4
+    if RUBY_PLATFORM =~ /mingw|mswin/
+      omit "pread(2) is not implemented."
+    end
+
     with_bigsrc {|bigsrc, bigcontent|
       File.open(bigsrc) {|f|
         assert_equal(0, f.pos)
@@ -916,9 +920,13 @@ class TestIO < Test::Unit::TestCase
         }
       }
     }
-  end if defined? UNIXSocket
+  end
 
   def test_copy_stream_socket5
+    if RUBY_PLATFORM =~ /mingw|mswin/
+      omit "pread(2) is not implemented."
+    end
+
     with_bigsrc {|bigsrc, bigcontent|
       File.open(bigsrc) {|f|
         assert_equal(bigcontent[0,100], f.read(100))
@@ -936,9 +944,13 @@ class TestIO < Test::Unit::TestCase
         }
       }
     }
-  end if defined? UNIXSocket
+  end
 
   def test_copy_stream_socket6
+    if RUBY_PLATFORM =~ /mingw|mswin/
+      omit "pread(2) is not implemented."
+    end
+
     mkcdtmpdir {
       megacontent = "abc" * 1234567
       File.open("megasrc", "w") {|f| f << megacontent }
@@ -959,9 +971,13 @@ class TestIO < Test::Unit::TestCase
         assert_equal(megacontent, result)
       }
     }
-  end if defined? UNIXSocket
+  end
 
   def test_copy_stream_socket7
+    if RUBY_PLATFORM =~ /mingw|mswin/
+      omit "pread(2) is not implemented."
+    end
+
     GC.start
     mkcdtmpdir {
       megacontent = "abc" * 1234567
@@ -996,7 +1012,7 @@ class TestIO < Test::Unit::TestCase
         end
       }
     }
-  end if defined? UNIXSocket and IO.method_defined?("nonblock=")
+  end
 
   def test_copy_stream_strio
     src = StringIO.new("abcd")
diff --git a/test/ruby/test_io_timeout.rb b/test/ruby/test_io_timeout.rb
index ca4c0b833b..e017395980 100644
--- a/test/ruby/test_io_timeout.rb
+++ b/test/ruby/test_io_timeout.rb
@@ -9,12 +9,6 @@ class TestIOTimeout < Test::Unit::TestCase
     begin
       i, o = UNIXSocket.pair
 
-      unless i.nonblock? && o.nonblock?
-        i.close
-        o.close
-        omit "I/O is not non-blocking!"
-      end
-
       yield i, o
     ensure
       i.close