[ruby/fileutils] Make copy methods handle FIFOs and UNIX sockets

Previously, this was broken.  Trying to copy a FIFO would raise a
NoMethodError if File.mkfifo was defined.  Trying to copy a UNIX
socket would raise a RuntimeError as File.mknod is not something
Ruby defines.

Handle the FIFO issue using File.mkfifo instead of mkfifo.

Handle the UNIX Socket issue by creating a unix socket.

Continue to not support character or block devices, raising a
RuntimeError for both.

Add tests for FIFO, UNIX Socket, and character/block devices.

https://github.com/ruby/fileutils/commit/123903532d

1 files changed, 12 insertions, 9 deletions

diff --git a/lib/fileutils.rb b/lib/fileutils.rb
index ee903e2519..bc4fd70bf2 100644
--- a/lib/fileutils.rb
+++ b/lib/fileutils.rb
@@ -1383,18 +1383,21 @@ module FileUtils
         end
       when symlink?
         File.symlink File.readlink(path()), dest
-      when chardev?
-        raise "cannot handle device file" unless File.respond_to?(:mknod)
-        mknod dest, ?c, 0666, lstat().rdev
-      when blockdev?
-        raise "cannot handle device file" unless File.respond_to?(:mknod)
-        mknod dest, ?b, 0666, lstat().rdev
+      when chardev?, blockdev?
+        raise "cannot handle device file"
       when socket?
-        raise "cannot handle socket" unless File.respond_to?(:mknod)
-        mknod dest, nil, lstat().mode, 0
+        begin
+          require 'socket'
+        rescue LoadError
+          raise "cannot handle socket"
+        else
+          raise "cannot handle socket" unless defined?(UNIXServer)
+        end
+        UNIXServer.new(dest).close
+        File.chmod lstat().mode, dest
       when pipe?
         raise "cannot handle FIFO" unless File.respond_to?(:mkfifo)
-        mkfifo dest, 0666
+        File.mkfifo dest, lstat().mode
       when door?
         raise "cannot handle door: #{path()}"
       else