merges r20372-r20375 and r20380 from trunk into ruby_1_9_1.

* signal.c (register_sigaltstack): minimum size is insufficient for
  method calls.

* signal.c (sigsegv): handles stack overflow if possible.

* thread.c (ruby_thread_stack_overflow): helper function to raise
  sysstack_error.

* thread_pthread.c (ruby_stack_overflowed_p): checks for stack
  overflow.

* signal.c (ruby_sigaction_t): added.

* signal.c (register_sigaltstack): stores alt stack for debug
  purpose.

git-svn-id: http://svn.ruby-lang.org/repos/ruby/branches/ruby_1_9_1@20422 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 8 insertions, 0 deletions

diff --git a/thread.c b/thread.c
index b9f7a28cd..25cdde28c 100644
--- a/thread.c
+++ b/thread.c
@@ -1184,6 +1184,14 @@ rb_thread_signal_exit(void *thptr)
     rb_thread_raise(2, argv, th->vm->main_thread);
 }
 
+void
+ruby_thread_stack_overflow(rb_thread_t *th)
+{
+    th->errinfo = sysstack_error;
+    th->raised_flag = 0;
+    TH_JUMP_TAG(th, TAG_RAISE);
+}
+
 int
 rb_thread_set_raised(rb_thread_t *th)
 {