Warn on access/modify of $SAFE, and remove effects of modifying $SAFE

This removes the security features added by $SAFE = 1, and warns for access
or modification of $SAFE from Ruby-level, as well as warning when calling
all public C functions related to $SAFE.

This modifies some internal functions that took a safe level argument
to no longer take the argument.

rb_require_safe now warns, rb_require_string has been added as a
version that takes a VALUE and does not warn.

One public C function that still takes a safe level argument and that
this doesn't warn for is rb_eval_cmd.  We may want to consider
adding an alternative method that does not take a safe level argument,
and warn for rb_eval_cmd.

1 files changed, 0 insertions, 17 deletions

diff --git a/test/ruby/test_thread.rb b/test/ruby/test_thread.rb
index e0efb7b2e0..adfad7e7e8 100644
--- a/test/ruby/test_thread.rb
+++ b/test/ruby/test_thread.rb
@@ -533,23 +533,6 @@ class TestThread < Test::Unit::TestCase
     waiter&.kill&.join
   end
 
-  def test_safe_level
-    ok = false
-    t = Thread.new do
-      EnvUtil.suppress_warning do
-        $SAFE = 1
-      end
-      ok = true
-      sleep
-    end
-    Thread.pass until ok
-    assert_equal($SAFE, Thread.current.safe_level)
-    assert_equal($SAFE, t.safe_level)
-  ensure
-    $SAFE = 0
-    t&.kill&.join
-  end
-
   def test_thread_local
     t = Thread.new { sleep }