From d9e7ada52aa79670eaad35894b31dd424c94b699 Mon Sep 17 00:00:00 2001
From: Andres Amaya Garcia <andres.amayagarcia@arm.com>
Date: Fri, 7 Jul 2017 13:03:23 +0100
Subject: [PATCH] Add library setup and teardown APIs

Add the following two functions to allow platform setup and teardown
operations for the full library to be hooked in:

* mbedtls_platform_setup()
* mbedtls_platform_teardown()

An mbedtls_platform_context C structure is also added and two internal
functions that are called by the corresponding setup and teardown
functions above:

* mbedtls_internal_platform_setup()
* mbedtls_internal_plartform_teardown()

Finally, the macro MBEDTLS_PLATFORM_SETUP_ALT is also added to allow
mbedtls_platform_context and internal function to be overriden by the
user as needed for a platform.
---
 include/mbedtls/config.h   |  1 +
 include/mbedtls/platform.h | 45 ++++++++++++++++++++++++++++++++++++++
 library/platform.c         | 30 +++++++++++++++++++++++++
 3 files changed, 76 insertions(+)

diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index b10d87375..ffeeb34af 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -163,6 +163,7 @@
 //#define MBEDTLS_PLATFORM_PRINTF_ALT
 //#define MBEDTLS_PLATFORM_SNPRINTF_ALT
 //#define MBEDTLS_PLATFORM_NV_SEED_ALT
+//#define MBEDTLS_PLATFORM_SETUP_ALT
 
 /**
  * \def MBEDTLS_DEPRECATED_WARNING
diff --git a/include/mbedtls/platform.h b/include/mbedtls/platform.h
index b1b019e55..a9ff7e421 100644
--- a/include/mbedtls/platform.h
+++ b/include/mbedtls/platform.h
@@ -288,6 +288,51 @@ int mbedtls_platform_set_nv_seed(
 #endif /* MBEDTLS_PLATFORM_NV_SEED_ALT */
 #endif /* MBEDTLS_ENTROPY_NV_SEED */
 
+#if !defined(MBEDTLS_PLATFORM_SETUP_ALT)
+typedef struct mbedtls_platform_context mbedtls_platform_context;
+#else
+#include "platform_alt.h"
+#endif /* !MBEDTLS_PLATFORM_SETUP_ALT */
+
+/**
+ * \brief   Perform any platform initialisation operations
+ *
+ * \param   ctx     mbed TLS context
+ *
+ * \return  0 if successful
+ *
+ * \note    This function should be called before any other library function
+ */
+int mbedtls_platform_setup( mbedtls_platform_context *ctx );
+/**
+ * \brief   Perform any platform teardown operations
+ *
+ * \param   ctx     mbed TLS context
+ *
+ * \return  0 if successful
+ *
+ * \note    This function should be after every other mbed TLS module has been
+ *          correctly freed using the appropriate free function.
+ */
+void mbedtls_platform_teardown( mbedtls_platform_context *ctx );
+
+/**
+ * \brief   Internal function to perform any platform initialisation operations
+ *          Only exposed to allow overriding it, see MBEDTLS_PLATFORM_SETUP_ALT
+ *
+ * \param   ctx     mbed TLS context
+ *
+ * \return  0 if successful
+ */
+int mbedtls_internal_platform_setup( mbedtls_platform_context *ctx );
+/**
+ * \brief   Internal function to perform any platform teardown operations
+ *          Only exposed to allow overriding it, see MBEDTLS_PLATFORM_SETUP_ALT
+ *
+ * \param   ctx     mbed TLS context
+ */
+void mbedtls_internal_platform_teardown( mbedtls_platform_context *ctx );
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/library/platform.c b/library/platform.c
index 8b336c38e..2ac67cbe9 100644
--- a/library/platform.c
+++ b/library/platform.c
@@ -304,4 +304,34 @@ int mbedtls_platform_set_nv_seed(
 #endif /* MBEDTLS_PLATFORM_NV_SEED_ALT */
 #endif /* MBEDTLS_ENTROPY_NV_SEED */
 
+int mbedtls_platform_setup( mbedtls_platform_context *ctx )
+{
+    return( mbedtls_internal_platform_setup( ctx ) );
+}
+
+void mbedtls_platform_teardown( mbedtls_platform_context *ctx )
+{
+    mbedtls_internal_platform_teardown( ctx );
+}
+
+#if !defined(MBEDTLS_PLATFORM_SETUP_ALT)
+/*
+ * Placeholder internal platform setup that does nothing by default
+ */
+int mbedtls_internal_platform_setup( mbedtls_platform_context *ctx )
+{
+    (void)ctx;
+
+    return( 0 );
+}
+
+/*
+ * Placeholder internal platform teardown that does nothing by default
+ */
+void mbedtls_internal_platform_teardown( mbedtls_platform_context *ctx )
+{
+    (void)ctx;
+}
+#endif /* MBEDTLS_PLATFORM_SETUP_ALT */
+
 #endif /* MBEDTLS_PLATFORM_C */