UTF LE is fixed at least the first 2 bytes
	
	* io.c (io_strip_bom): if the first 2 bytes are 0xFF0xFE, it
	  should be a little-endian UTF, 16 or 32.  [Bug #16099]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@67772 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

	Always mark the string returned by File.realpath as tainted

	This string can include elements that were not in either string
	passed to File.realpath, even if one of the strings is an
	absolute path, due to symlinks:

	```ruby
	Dir.mkdir('b') unless File.directory?('b')
	File.write('b/a', '') unless File.file?('b/a')
	File.symlink('b', 'c') unless File.symlink?('c')
	path = File.realpath('c/a'.untaint, Dir.pwd.untaint)
	path # "/home/testr/ruby/b/a"
	path.tainted? # should be true, as 'b' comes from file system
	```

	[Bug #15803]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@67755 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

	file.c: get rid of useless conversion

	* file.c (rb_file_s_stat): File.stat does not accept an IO
	  object as trying conversion to path name string first.  skip
	  conversion to IO and try stat(2) only.

	file.c: realpath on special symlink

	* file.c (realpath_rec): fallback to symlink path when it is
	  accessible but the link target is not actual entry on file
	  systems.  [ruby-dev:50487] [Bug #14557]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@62632 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* test/ruby/test_file.rb (test_open_tempfile_path): skip EOPNOTSUPP
  (observed on Ubuntu 16 on Docker).


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61318 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* file.c (rb_check_realpath_internal): infetct the result with
  arguments, no taint if none are tainted and cwd is not used.
  [ruby-core:83583] [Bug #14060]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60599 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60598 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* file.c (rb_check_realpath_internal): infetct the result with
  arguments, no taint if none are tainted and cwd is not used.
  [ruby-core:83583] [Bug #14060]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60596 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60139 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

Looks like File::Constants::TMPFILE could be defined even when not
supported on system.  Just skip the test when we get EINVAL on open(2).

* test/ruby/test_file.rb(test_open_tempfile_path):
  Skip when EINVAL occured on File.open.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59706 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

File#path for a file opened with O_TMPFILE has no meaning.

A filepath returned by this method isn't guarranteed about its accuracy,
but files opened with O_TMPFILE are known its recorded path has no
meaning. So let them not to return any pathname.

After a discussion in ruby-core, just returning Qnil makes guessing the
root cause difficult. Instead, this patch makes the method to raise an
error.

Other consideration is calling fnctl(2) on rb_file_path, but it adds a
overhead, and it's difficult to determine O_TMPFILE status  after fd has
been closed.

[Feature #13568]

* io.c(rb_file_open_generic): Set Qnil to fptr->pathv when opening a
  file using O_TMPFILE

* file.c(rb_file_path): Raise IOError when fptr->pathv is Qnil

* file.c(rb_file_path): [DOC] Update for the new behavior

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59704 b2dd03c8-39d4-4d8f-98ff-823fe69b080e