thread.c: stop if forked in a sub-thread

* thread.c (thread_start_func_2): stop if forked in a sub-thread,
  the thread has become the main thread.
  [ruby-core:62070] [Bug #9751]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45899 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Sat May 10 13:32:18 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* thread.c (thread_start_func_2): stop if forked in a sub-thread,
+	  the thread has become the main thread.
+	  [ruby-core:62070] [Bug #9751]
+
 Sat May 10 09:32:19 2014  SHIBATA Hiroshi  <shibata.hiroshi@gmail.com>
 
 	* man/ruby.1: remove deadlink. [ruby-core:62145][Bug #9773]

test/ruby/test_thread.rb

@@ -973,4 +973,25 @@ Thread.new(Thread.current) {|mth|
     pid, status = Process.waitpid2(pid)
     assert_equal(false, status.success?, bug8433)
   end if Process.respond_to?(:fork)
+
+  def test_fork_in_thread
+    bug9751 = '[ruby-core:62070] [Bug #9751]'
+    f = nil
+    th = Thread.start do
+      unless f = IO.popen("-")
+        STDERR.reopen(STDOUT)
+        exit
+      end
+      Process.wait2(f.pid)
+    end
+    unless th.join(3)
+      Process.kill(:QUIT, f.pid)
+      Process.kill(:KILL, f.pid) unless th.join(1)
+    end
+    _, status = th.value
+    output = f.read
+    f.close
+    assert_not_predicate(status, :signaled?, FailDesc[status, bug9751, output])
+    assert_predicate(status, :success?, bug9751)
+  end if Process.respond_to?(:fork)
 end

thread.c

@@ -569,6 +569,9 @@ thread_start_func_2(rb_thread_t *th, VALUE *stack_start, VALUE *register_stack_s
 	thread_debug("thread end: %p\n", (void *)th);
 
 	main_th = th->vm->main_thread;
+	if (main_th == th) {
+	    ruby_stop(0);
+	}
 	if (RB_TYPE_P(errinfo, T_OBJECT)) {
 	    /* treat with normal error object */
 	    rb_threadptr_raise(main_th, 1, &errinfo);