add platform_set_snprintf

include/polarssl/check_config.h

@@ -198,6 +198,11 @@
 #error "POLARSSL_PKCS11_C defined, but not all prerequisites"
 #endif
 
+#if defined(POLARSSL_PLATFORM_SNPRINTF_ALT) && ( defined(_WIN32)\
+    && !defined(EFIX64) && !defined(EFI32) )
+#error "POLARSSL_PLATFORM_SNPRINTF_ALT defined but not available on Windows"
+#endif
+
 #if defined(POLARSSL_RSA_C) && ( !defined(POLARSSL_BIGNUM_C) ||         \
     !defined(POLARSSL_OID_C) )
 #error "POLARSSL_RSA_C defined, but not all prerequisites"

include/polarssl/config.h

@@ -159,9 +159,13 @@
  *
  * All these define require POLARSSL_PLATFORM_C to be defined!
  *
+ * WARNING: POLARSSL_PLATFORM_SNPRINTF_ALT is not available on Windows
+ * for compatibility reasons.
+ *
  * Uncomment a macro to enable alternate implementation of specific base
  * platform function
  */
+//#define POLARSSL_PLATFORM_SNPRINTF_ALT
 //#define POLARSSL_PLATFORM_PRINTF_ALT
 //#define POLARSSL_PLATFORM_FPRINTF_ALT
 /* \} name SECTION: System support */
@@ -1890,7 +1894,7 @@
  * \def POLARSSL_PLATFORM_C
  *
  * Enable the platform abstraction layer that allows you to re-assign
- * functions like malloc(), free(), printf(), fprintf()
+ * functions like malloc(), free(), snprintf(), printf(), fprintf()
  *
  * Module:  library/platform.c
  * Caller:  Most other .c files
@@ -2238,6 +2242,7 @@
 //#define POLARSSL_PLATFORM_STD_MEM_HDR <stdlib.h> /**< Header to include if POLARSSL_PLATFORM_NO_STD_FUNCTIONS is defined. Don't define if no header is needed. */
 //#define POLARSSL_PLATFORM_STD_MALLOC   malloc /**< Default allocator to use, can be undefined */
 //#define POLARSSL_PLATFORM_STD_FREE       free /**< Default free to use, can be undefined */
+//#define POLARSSL_PLATFORM_STD_SNPRINTF 	snprintf /**< Default snprintf to use, can be undefined */
 //#define POLARSSL_PLATFORM_STD_PRINTF   printf /**< Default printf to use, can be undefined */
 //#define POLARSSL_PLATFORM_STD_FPRINTF fprintf /**< Default fprintf to use, can be undefined */
 

include/polarssl/platform.h

@@ -50,6 +50,9 @@ extern "C" {
 #if !defined(POLARSSL_PLATFORM_NO_STD_FUNCTIONS)
 #include <stdio.h>
 #include <stdlib.h>
+#if !defined(POLARSSL_PLATFORM_STD_SNPRINTF)
+#define POLARSSL_PLATFORM_STD_SNPRINTF   snprintf /**< Default snprintf to use  */
+#endif
 #if !defined(POLARSSL_PLATFORM_STD_PRINTF)
 #define POLARSSL_PLATFORM_STD_PRINTF   printf /**< Default printf to use  */
 #endif
@@ -92,6 +95,25 @@ int platform_set_malloc_free( void * (*malloc_func)( size_t ),
 #define polarssl_free       free
 #endif /* POLARSSL_PLATFORM_MEMORY */
 
+/*
+ * The function pointers for snprintf
+ */
+#if defined(POLARSSL_PLATFORM_SNPRINTF_ALT)
+extern int (*polarssl_snprintf)( char * s, size_t n, const char * format, ... );
+
+/**
+ * \brief   Set your own snprintf function pointer
+ *
+ * \param snprintf_func   the snprintf function implementation
+ *
+ * \return              0
+ */
+int platform_set_snprintf( int (*snprintf_func)( char * s, size_t n,
+                                                 const char * format, ... ) );
+#else /* POLARSSL_PLATFORM_SNPRINTF_ALT */
+#define polarssl_snprintf   snprintf
+#endif /* POLARSSL_PLATFORM_SNPRINTF_ALT */
+
 /*
  * The function pointers for printf
  */

library/platform.c

@@ -62,6 +62,36 @@ int platform_set_malloc_free( void * (*malloc_func)( size_t ),
 }
 #endif /* POLARSSL_PLATFORM_MEMORY */
 
+#if defined(POLARSSL_PLATFORM_SNPRINTF_ALT)
+#if !defined(POLARSSL_PLATFORM_STD_SNPRINTF)
+/*
+ * Make dummy function to prevent NULL pointer dereferences
+ */
+static int platform_snprintf_uninit( char * s, size_t n,
+                                     const char * format, ... )
+{
+    ((void) s);
+    ((void) n);
+    ((void) format)
+    return( 0 );
+}
+
+#define POLARSSL_PLATFORM_STD_SNPRINTF    platform_snprintf_uninit
+#endif /* !POLARSSL_PLATFORM_STD_SNPRINTF */
+
+int (*polarssl_snprintf)( char * s, size_t n,
+                          const char * format,
+                          ... ) = POLARSSL_PLATFORM_STD_SNPRINTF;
+
+int platform_set_snprintf( int (*snprintf_func)( char * s, size_t n,
+                                                 const char * format,
+                                                 ... ) )
+{
+    polarssl_snprintf = snprintf_func;
+    return( 0 );
+}
+#endif /* POLARSSL_PLATFORM_SNPRINTF_ALT */
+
 #if defined(POLARSSL_PLATFORM_PRINTF_ALT)
 #if !defined(POLARSSL_PLATFORM_STD_PRINTF)
 /*