Move bignum code path testing out of the library
Without this, it's not at all obvious that turning on MBEDTLS_TEST_HOOKS
doesn't change the functional behavior of the code.
Signed-off-by: Janos Follath <janos.follath@arm.com>
diff --git a/tests/include/test/bignum_codepath_check.h b/tests/include/test/bignum_codepath_check.h
new file mode 100644
index 0000000..6ab68bb
--- /dev/null
+++ b/tests/include/test/bignum_codepath_check.h
@@ -0,0 +1,48 @@
+/** Support for path tracking in optionally safe bignum functions
+ *
+ * The functions are called when an optionally safe path is taken and logs it with a single
+ * variable. This variable is at any time in one of three states:
+ * - MBEDTLS_MPI_IS_TEST: No optionally safe path has been taken since the last reset
+ * - MBEDTLS_MPI_IS_SECRET: Only safe paths were teken since the last reset
+ * - MBEDTLS_MPI_IS_PUBLIC: At least one unsafe path has been taken since the last reset
+ *
+ * Using a simple global variable to track execution path. Making it work with multithreading
+ * doesn't worth the effort as multithreaded tests add little to no value here.
+ */
+/*
+ * Copyright The Mbed TLS Contributors
+ * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#ifndef BIGNUM_CODEPATH_CHECK_H
+#define BIGNUM_CODEPATH_CHECK_H
+
+#include "bignum_core.h"
+
+#if defined(MBEDTLS_TEST_HOOKS) && !defined(MBEDTLS_THREADING_C)
+
+extern int mbedtls_codepath_check;
+
+/**
+ * \brief Setup the codepath test hooks used by optionally safe bignum functions to signal
+ * the path taken.
+ */
+void mbedtls_codepath_test_hooks_setup(void);
+
+/**
+ * \brief Teardown the codepath test hooks used by optionally safe bignum functions to
+ * signal the path taken.
+ */
+void mbedtls_codepath_test_hooks_teardown(void);
+
+/**
+ * \brief Reset the state of the codepath to the initial state.
+ */
+static inline void mbedtls_codepath_reset(void)
+{
+ mbedtls_codepath_check = MBEDTLS_MPI_IS_TEST;
+}
+
+#endif /* MBEDTLS_TEST_HOOKS && !MBEDTLS_THREADING_C */
+
+#endif /* BIGNUM_CODEPATH_CHECK_H */