merges r32345 from trunk into ruby_1_9_2.

--
* thread.c (rb_threadptr_check_signal): only wake up main thread.
* thread.c (rb_threadptr_execute_interrupts_common): check signal
  deliverly if it is main thread.
  fixes [ruby-dev:44005] [Ruby 1.9 - Bug #4950]
* bootstraptest/test_fork.rb: add a test for above.
* signal.c (rb_get_next_signal): skip if signal_buff is empty.
  (check signal_buff.size first)
* vm_core.h: remove unused variable rb_thread_t::exec_signal.
* thread.c (rb_thread_check_trap_pending): check
  rb_signal_buff_size() because rb_thread_t::exec_signal
  is no longer available.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@32926 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 11 insertions, 9 deletions

diff --git a/signal.c b/signal.c
index f952659657..30c565b119 100644
--- a/signal.c
+++ b/signal.c
@@ -566,16 +566,18 @@ rb_get_next_signal(void)
 {
     int i, sig = 0;
 
-    for (i=1; i<RUBY_NSIG; i++) {
-	if (signal_buff.cnt[i] > 0) {
-	    rb_disable_interrupt();
-	    {
-		ATOMIC_DEC(signal_buff.cnt[i]);
-		ATOMIC_DEC(signal_buff.size);
+    if (signal_buff.size != 0) {
+	for (i=1; i<RUBY_NSIG; i++) {
+	    if (signal_buff.cnt[i] > 0) {
+		rb_disable_interrupt();
+		{
+		    ATOMIC_DEC(signal_buff.cnt[i]);
+		    ATOMIC_DEC(signal_buff.size);
+		}
+		rb_enable_interrupt();
+		sig = i;
+		break;
 	    }
-	    rb_enable_interrupt();
-	    sig = i;
-	    break;
 	}
     }
     return sig;