From b879fabf36a45171cc35a894545e97c9a7be3bb8 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@cloudius-systems.com>
Date: Mon, 22 Jun 2015 12:48:50 +0300
Subject: [PATCH] reactor: block SIGALRM while we're still not ready to handle
 it

If some code sets up a timer before we've set up the SIGALRM signal handler,
we die.  Block it in the meantime.
---
 core/reactor.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/core/reactor.cc b/core/reactor.cc
index 6e8d94ba5a..ba0651978d 100644
--- a/core/reactor.cc
+++ b/core/reactor.cc
@@ -204,6 +204,11 @@ reactor::reactor()
     sev.sigev_signo = SIGALRM;
     r = timer_create(CLOCK_REALTIME, &sev, &_timer);
     assert(r >= 0);
+    sigset_t mask;
+    sigemptyset(&mask);
+    sigaddset(&mask, SIGALRM);
+    r = ::sigprocmask(SIG_BLOCK, &mask, NULL);
+    assert(r == 0);
 #endif
     memory::set_reclaim_hook([this] (std::function<void ()> reclaim_fn) {
         // push it in the front of the queue so we reclaim memory quickly