Mutex usage testing: set up wrapper functions

When using pthread mutexes (MBEDTLS_THREADING_C and
MBEDTLS_THREADING_PTHREAD enabled), and when test hooks are
enabled (MBEDTLS_TEST_HOOKS), set up wrappers around the
mbedtls_mutex_xxx abstraction. In this commit, the wrapper functions
don't do anything yet.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

tests/include/test/helpers.h

@@ -260,4 +260,13 @@ void mbedtls_test_param_failed_reset_state( void );
 #include "test/fake_external_rng_for_test.h"
 #endif
 
+#if defined(MBEDTLS_THREADING_C) && defined(MBEDTLS_THREADING_PTHREAD) && \
+    defined(MBEDTLS_TEST_HOOKS)
+#define MBEDTLS_TEST_MUTEX_USAGE
+
+/** Permanently activate the mutex usage verification framework. See
+ * threading_helpers.c for information. */
+void mbedtls_test_mutex_usage_init( void );
+#endif /* MBEDTLS_TEST_MUTEX_USAGE */
+
 #endif /* TEST_HELPERS_H */

tests/src/threading_helpers.c

@@ -0,0 +1,69 @@
+/** Mutex usage verification framework. */
+
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+#include <test/helpers.h>
+#include <test/macros.h>
+
+#if defined(MBEDTLS_TEST_MUTEX_USAGE)
+
+#include "mbedtls/threading.h"
+
+typedef struct
+{
+    void (*init)( mbedtls_threading_mutex_t * );
+    void (*free)( mbedtls_threading_mutex_t * );
+    int (*lock)( mbedtls_threading_mutex_t * );
+    int (*unlock)( mbedtls_threading_mutex_t * );
+} mutex_functions_t;
+static mutex_functions_t mutex_functions;
+
+static void mbedtls_test_wrap_mutex_init( mbedtls_threading_mutex_t *mutex )
+{
+    mutex_functions.init( mutex );
+}
+
+static void mbedtls_test_wrap_mutex_free( mbedtls_threading_mutex_t *mutex )
+{
+    mutex_functions.free( mutex );
+}
+
+static int mbedtls_test_wrap_mutex_lock( mbedtls_threading_mutex_t *mutex )
+{
+    int ret = mutex_functions.lock( mutex );
+    return( ret );
+}
+
+static int mbedtls_test_wrap_mutex_unlock( mbedtls_threading_mutex_t *mutex )
+{
+    return( mutex_functions.unlock( mutex ) );
+}
+
+void mbedtls_test_mutex_usage_init( void )
+{
+    mutex_functions.init = mbedtls_mutex_init;
+    mutex_functions.free = mbedtls_mutex_free;
+    mutex_functions.lock = mbedtls_mutex_lock;
+    mutex_functions.unlock = mbedtls_mutex_unlock;
+    mbedtls_mutex_init = &mbedtls_test_wrap_mutex_init;
+    mbedtls_mutex_free = &mbedtls_test_wrap_mutex_free;
+    mbedtls_mutex_lock = &mbedtls_test_wrap_mutex_lock;
+    mbedtls_mutex_unlock = &mbedtls_test_wrap_mutex_unlock;
+}
+
+#endif /* MBEDTLS_TEST_MUTEX_USAGE */

tests/suites/host_test.function

@@ -536,6 +536,10 @@ int execute_tests( int argc , const char ** argv )
     mbedtls_memory_buffer_alloc_init( alloc_buf, sizeof( alloc_buf ) );
 #endif
 
+#if defined(MBEDTLS_TEST_MUTEX_USAGE)
+    mbedtls_test_mutex_usage_init( );
+#endif
+
     /*
      * The C standard doesn't guarantee that all-bits-0 is the representation
      * of a NULL pointer. We do however use that in our code for initializing

visualc/VS2010/mbedTLS.vcxproj

@@ -358,6 +358,7 @@
     <ClCompile Include="..\..\tests\src\helpers.c" />
     <ClCompile Include="..\..\tests\src\psa_crypto_helpers.c" />
     <ClCompile Include="..\..\tests\src\random.c" />
+    <ClCompile Include="..\..\tests\src\threading_helpers.c" />
     <ClCompile Include="..\..\3rdparty\everest\library\everest.c" />
     <ClCompile Include="..\..\3rdparty\everest\library\Hacl_Curve25519_joined.c" />
     <ClCompile Include="..\..\3rdparty\everest\library\x25519.c" />