Merge pull request #321 from matejk/fix_algo_registry_locking_windows

Algo_Registry: Use CRITICAL_SECTION on Windows to prevent hang during initialization

3 files changed, 60 insertions, 6 deletions

diff --git a/doc/credits.rst b/doc/credits.rst
index 8a18d2237..6d62b6380 100644
--- a/doc/credits.rst
+++ b/doc/credits.rst
@@ -55,6 +55,11 @@ snail-mail address (S), and Bitcoin address (B).
   D: LZMA compression module
   S: Czech Republic
 
+  N: Matej Kenda
+  E: [email protected]
+  D: Locking in Algo_Registry for Windows OS
+  S: Slovenia
+
   N: Adam Langley
   E: [email protected]
   D: Curve25519
diff --git a/doc/license.txt b/doc/license.txt
index 4e3907f48..2eb91b622 100644
--- a/doc/license.txt
+++ b/doc/license.txt
@@ -24,6 +24,7 @@ Copyright (C) 1999-2013,2014,2015 Jack Lloyd
               2014 Andrew Moon
               2015 Daniel Seither (Kullo GmbH)
               2015 Simon Warta (Kullo GmbH)
+              2015 Matej Kenda (TopIT d.o.o.)
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
diff --git a/src/lib/base/algo_registry.h b/src/lib/base/algo_registry.h
index e16522d94..eec1ce88d 100644
--- a/src/lib/base/algo_registry.h
+++ b/src/lib/base/algo_registry.h
@@ -1,5 +1,6 @@
 /*
 * (C) 2014,2015 Jack Lloyd
+* (C) 2015 Matej Kenda
 *
 * Botan is released under the Simplified BSD License (see license.txt)
 */
@@ -16,8 +17,48 @@
 #include <string>
 #include <unordered_map>
 
+#if defined(_MSC_VER) && (_MSC_VER <= 1800)
+
+   #define BOTAN_WORKAROUND_GH_321
+   #define NOMINMAX 1
+   #define WIN32_LEAN_AND_MEAN 1
+   #include <Windows.h>
+
+#endif
+
 namespace Botan {
 
+#if defined(BOTAN_WORKAROUND_GH_321)
+
+class WinCS_Mutex
+   {
+   public:
+       WinCS_Mutex()
+          {
+          InitializeCriticalSection(&m_cs);
+          }
+          
+       ~WinCS_Mutex()
+          {
+          DeleteCriticalSection(&m_cs);
+          }
+
+       void lock()
+          {
+          EnterCriticalSection(&m_cs);
+          }
+
+       void unlock()
+          {
+          LeaveCriticalSection(&m_cs);
+          }
+
+    private:
+        CRITICAL_SECTION   m_cs;
+   };
+
+#endif
+
 template<typename T>
 class Algo_Registry
    {
@@ -34,14 +75,14 @@ class Algo_Registry
 
       void add(const std::string& name, const std::string& provider, maker_fn fn, byte pref)
          {
-         std::unique_lock<std::mutex> lock(m_mutex);
+         std::lock_guard<mutex> lock(m_mutex);
          if(!m_algo_info[name].add_provider(provider, fn, pref))
             throw std::runtime_error("Duplicated registration of " + name + "/" + provider);
          }
 
       std::vector<std::string> providers_of(const Spec& spec)
          {
-         std::unique_lock<std::mutex> lock(m_mutex);
+         std::lock_guard<mutex> lock(m_mutex);
          auto i = m_algo_info.find(spec.algo_name());
          if(i != m_algo_info.end())
             return i->second.providers();
@@ -50,7 +91,7 @@ class Algo_Registry
 
       void set_provider_preference(const Spec& spec, const std::string& provider, byte pref)
          {
-         std::unique_lock<std::mutex> lock(m_mutex);
+         std::lock_guard<mutex> lock(m_mutex);
          auto i = m_algo_info.find(spec.algo_name());
          if(i != m_algo_info.end())
             i->second.set_pref(provider, pref);
@@ -92,11 +133,18 @@ class Algo_Registry
          };
 
    private:
-      Algo_Registry() {}
+
+#if defined(BOTAN_WORKAROUND_GH_321)
+      using mutex = WinCS_Mutex;
+#else
+      using mutex = std::mutex;
+#endif
+
+      Algo_Registry()  { }
 
       std::vector<maker_fn> get_makers(const Spec& spec, const std::string& provider)
          {
-         std::unique_lock<std::mutex> lock(m_mutex);
+         std::lock_guard<mutex> lock(m_mutex);
          return m_algo_info[spec.algo_name()].get_makers(provider);
          }
 
@@ -158,7 +206,7 @@ class Algo_Registry
             std::unordered_map<std::string, maker_fn> m_maker_fns;
          };
 
-      std::mutex m_mutex;
+      mutex m_mutex;
       std::unordered_map<std::string, Algo_Info> m_algo_info;
    };