Abstracts away time()/stdlib.h into platform

Substitutes time() into a configurable platform interface to allow it to be
easily substituted.
diff --git a/library/debug.c b/library/debug.c
index 4752ab1..a032478 100644
--- a/library/debug.c
+++ b/library/debug.c
@@ -27,21 +27,22 @@
 
 #if defined(MBEDTLS_DEBUG_C)
 
-#include "mbedtls/debug.h"
-
-#include <stdarg.h>
-#include <stdio.h>
-#include <string.h>
-
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #include <stdlib.h>
 #define mbedtls_calloc      calloc
 #define mbedtls_free        free
+#define mbedtls_time_t      time_t
 #define mbedtls_snprintf    snprintf
 #endif
 
+#include "mbedtls/debug.h"
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+
 #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
     !defined(inline) && !defined(__cplusplus)
 #define inline __inline
diff --git a/library/net.c b/library/net.c
index 3b78b6b..4142bc0 100644
--- a/library/net.c
+++ b/library/net.c
@@ -32,6 +32,13 @@
 #error "This module only works on Unix and Windows, see MBEDTLS_NET_C in config.h"
 #endif
 
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_time_t    time_t
+#endif
+
 #include "mbedtls/net.h"
 
 #include <string.h>
@@ -86,7 +93,6 @@
 #define MSVC_INT_CAST
 #endif
 
-#include <stdlib.h>
 #include <stdio.h>
 
 #include <time.h>
diff --git a/library/platform.c b/library/platform.c
index d634c62..e7ec0ad 100644
--- a/library/platform.c
+++ b/library/platform.c
@@ -190,4 +190,27 @@
 }
 #endif /* MBEDTLS_PLATFORM_EXIT_ALT */
 
+#if defined(MBEDTLS_PLATFORM_TIME_ALT)
+#if !defined(MBEDTLS_PLATFORM_STD_TIME)
+/*
+ * Make dummy function to prevent NULL pointer dereferences
+ */
+static mbedtls_time_t platform_time_uninit( mbedtls_time_t* timer )
+{
+    ((void) timer);
+    return( NULL );
+}
+
+#define MBEDTLS_PLATFORM_STD_TIME   platform_time_uninit
+#endif /* !MBEDTLS_PLATFORM_STD_TIME */
+
+time_t (*mbedtls_time)( mbedtls_time_t* timer ) = MBEDTLS_PLATFORM_STD_TIME;
+
+int mbedtls_platform_set_exit( mbedtls_time_t (*time_func)( mbedtls_time_t timer ) )
+{
+    mbedtls_time = time_func;
+    return( 0 );
+}
+#endif /* MBEDTLS_PLATFORM_TIME_ALT */
+
 #endif /* MBEDTLS_PLATFORM_C */
diff --git a/library/ssl_cache.c b/library/ssl_cache.c
index 711bc53..01c66ae 100644
--- a/library/ssl_cache.c
+++ b/library/ssl_cache.c
@@ -31,18 +31,20 @@
 
 #if defined(MBEDTLS_SSL_CACHE_C)
 
-#include "mbedtls/ssl_cache.h"
-
-#include <string.h>
-
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #include <stdlib.h>
 #define mbedtls_calloc    calloc
-#define mbedtls_free       free
+#define mbedtls_free      free
+#define mbedtls_time      time
+#define mbedtls_time_t    time_t
 #endif
 
+#include "mbedtls/ssl_cache.h"
+
+#include <string.h>
+
 void mbedtls_ssl_cache_init( mbedtls_ssl_cache_context *cache )
 {
     memset( cache, 0, sizeof( mbedtls_ssl_cache_context ) );
@@ -59,7 +61,7 @@
 {
     int ret = 1;
 #if defined(MBEDTLS_HAVE_TIME)
-    time_t t = time( NULL );
+    mbedtls_time_t t = mbedtls_time( NULL );
 #endif
     mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data;
     mbedtls_ssl_cache_entry *cur, *entry;
@@ -138,7 +140,7 @@
 {
     int ret = 1;
 #if defined(MBEDTLS_HAVE_TIME)
-    time_t t = time( NULL ), oldest = 0;
+    mbedtls_time_t t = time( NULL ), oldest = 0;
     mbedtls_ssl_cache_entry *old = NULL;
 #endif
     mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data;
diff --git a/library/ssl_ciphersuites.c b/library/ssl_ciphersuites.c
index 949b9ed..3546331 100644
--- a/library/ssl_ciphersuites.c
+++ b/library/ssl_ciphersuites.c
@@ -29,10 +29,16 @@
 
 #if defined(MBEDTLS_SSL_TLS_C)
 
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_time_t    time_t
+#endif
+
 #include "mbedtls/ssl_ciphersuites.h"
 #include "mbedtls/ssl.h"
 
-// #include <stdlib.h>
 #include <string.h>
 
 /*
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 7f5b94e..cd39db0 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -27,20 +27,22 @@
 
 #if defined(MBEDTLS_SSL_CLI_C)
 
-#include "mbedtls/debug.h"
-#include "mbedtls/ssl.h"
-#include "mbedtls/ssl_internal.h"
-
-#include <string.h>
-
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #include <stdlib.h>
 #define mbedtls_calloc    calloc
-#define mbedtls_free       free
+#define mbedtls_free      free
+#define mbedtls_time      time
+#define mbedtls_time_t    time_t
 #endif
 
+#include "mbedtls/debug.h"
+#include "mbedtls/ssl.h"
+#include "mbedtls/ssl_internal.h"
+
+#include <string.h>
+
 #include <stdint.h>
 
 #if defined(MBEDTLS_HAVE_TIME)
@@ -669,7 +671,7 @@
     int ret;
     unsigned char *p = ssl->handshake->randbytes;
 #if defined(MBEDTLS_HAVE_TIME)
-    time_t t;
+    mbedtls_time_t t;
 #endif
 
     /*
@@ -684,7 +686,7 @@
 #endif
 
 #if defined(MBEDTLS_HAVE_TIME)
-    t = time( NULL );
+    t = mbedtls_time( NULL );
     *p++ = (unsigned char)( t >> 24 );
     *p++ = (unsigned char)( t >> 16 );
     *p++ = (unsigned char)( t >>  8 );
@@ -1592,7 +1594,7 @@
         ssl->state++;
         ssl->handshake->resume = 0;
 #if defined(MBEDTLS_HAVE_TIME)
-        ssl->session_negotiate->start = time( NULL );
+        ssl->session_negotiate->start = mbedtls_time( NULL );
 #endif
         ssl->session_negotiate->ciphersuite = i;
         ssl->session_negotiate->compression = comp;
diff --git a/library/ssl_cookie.c b/library/ssl_cookie.c
index 7e0c573..f241c86 100644
--- a/library/ssl_cookie.c
+++ b/library/ssl_cookie.c
@@ -31,16 +31,18 @@
 
 #if defined(MBEDTLS_SSL_COOKIE_C)
 
-#include "mbedtls/ssl_cookie.h"
-#include "mbedtls/ssl_internal.h"
-
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #define mbedtls_calloc    calloc
-#define mbedtls_free       free
+#define mbedtls_free      free
+#define mbedtls_time      time
+#define mbedtls_time_t    time_t
 #endif
 
+#include "mbedtls/ssl_cookie.h"
+#include "mbedtls/ssl_internal.h"
+
 #include <string.h>
 
 /* Implementation that should never be optimized out by the compiler */
@@ -172,7 +174,7 @@
         return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
 
 #if defined(MBEDTLS_HAVE_TIME)
-    t = (unsigned long) time( NULL );
+    t = (unsigned long) mbedtls_time( NULL );
 #else
     t = ctx->serial++;
 #endif
@@ -242,7 +244,7 @@
         return( -1 );
 
 #if defined(MBEDTLS_HAVE_TIME)
-    cur_time = (unsigned long) time( NULL );
+    cur_time = (unsigned long) mbedtls_time( NULL );
 #else
     cur_time = ctx->serial;
 #endif
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 6bd0b59..9fc21a5 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -27,6 +27,16 @@
 
 #if defined(MBEDTLS_SSL_SRV_C)
 
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_calloc    calloc
+#define mbedtls_free      free
+#define mbedtls_time      time
+#define mbedtls_time_t    time_t
+#endif
+
 #include "mbedtls/debug.h"
 #include "mbedtls/ssl.h"
 #include "mbedtls/ssl_internal.h"
@@ -37,14 +47,6 @@
 #include "mbedtls/ecp.h"
 #endif
 
-#if defined(MBEDTLS_PLATFORM_C)
-#include "mbedtls/platform.h"
-#else
-#include <stdlib.h>
-#define mbedtls_calloc    calloc
-#define mbedtls_free       free
-#endif
-
 #if defined(MBEDTLS_HAVE_TIME)
 #include <time.h>
 #endif
@@ -2210,7 +2212,7 @@
 static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
 {
 #if defined(MBEDTLS_HAVE_TIME)
-    time_t t;
+    mbedtls_time_t t;
 #endif
     int ret;
     size_t olen, ext_len = 0, n;
@@ -2253,7 +2255,7 @@
                         buf[4], buf[5] ) );
 
 #if defined(MBEDTLS_HAVE_TIME)
-    t = time( NULL );
+    t = mbedtls_time( NULL );
     *p++ = (unsigned char)( t >> 24 );
     *p++ = (unsigned char)( t >> 16 );
     *p++ = (unsigned char)( t >>  8 );
@@ -2302,7 +2304,7 @@
         ssl->state++;
 
 #if defined(MBEDTLS_HAVE_TIME)
-        ssl->session_negotiate->start = time( NULL );
+        ssl->session_negotiate->start = mbedtls_time( NULL );
 #endif
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
diff --git a/library/ssl_ticket.c b/library/ssl_ticket.c
index 0e27900..5d77403 100644
--- a/library/ssl_ticket.c
+++ b/library/ssl_ticket.c
@@ -27,16 +27,18 @@
 
 #if defined(MBEDTLS_SSL_TICKET_C)
 
-#include "mbedtls/ssl_ticket.h"
-
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #include <stdlib.h>
 #define mbedtls_calloc    calloc
-#define mbedtls_free       free
+#define mbedtls_free      free
+#define mbedtls_time      time
+#define mbedtls_time_t    time_t
 #endif
 
+#include "mbedtls/ssl_ticket.h"
+
 #include <string.h>
 
 /* Implementation that should never be optimized out by the compiler */
@@ -69,7 +71,7 @@
     mbedtls_ssl_ticket_key *key = ctx->keys + index;
 
 #if defined(MBEDTLS_HAVE_TIME)
-    key->generation_time = (uint32_t) time( NULL );
+    key->generation_time = (uint32_t) mbedtls_time( NULL );
 #endif
 
     if( ( ret = ctx->f_rng( ctx->p_rng, key->name, sizeof( key->name ) ) ) != 0 )
@@ -98,7 +100,7 @@
 #else
     if( ctx->ticket_lifetime != 0 )
     {
-        uint32_t current_time = (uint32_t) time( NULL );
+        uint32_t current_time = (uint32_t) mbedtls_time( NULL );
         uint32_t key_time = ctx->keys[ctx->active].generation_time;
 
         if( current_time > key_time &&
@@ -451,7 +453,7 @@
 #if defined(MBEDTLS_HAVE_TIME)
     {
         /* Check for expiration */
-        time_t current_time = time( NULL );
+        mbedtls_time_t current_time = mbedtls_time( NULL );
 
         if( current_time < session->start ||
             (uint32_t)( current_time - session->start ) > ctx->ticket_lifetime )
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 1c44b7d..19cc357 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -35,6 +35,15 @@
 
 #if defined(MBEDTLS_SSL_TLS_C)
 
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_calloc    calloc
+#define mbedtls_free      free
+#define mbedtls_time_t    time_t
+#endif
+
 #include "mbedtls/debug.h"
 #include "mbedtls/ssl.h"
 #include "mbedtls/ssl_internal.h"
@@ -46,14 +55,6 @@
 #include "mbedtls/oid.h"
 #endif
 
-#if defined(MBEDTLS_PLATFORM_C)
-#include "mbedtls/platform.h"
-#else
-#include <stdlib.h>
-#define mbedtls_calloc    calloc
-#define mbedtls_free       free
-#endif
-
 /* Implementation that should never be optimized out by the compiler */
 static void mbedtls_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = v; while( n-- ) *p++ = 0;
diff --git a/library/x509.c b/library/x509.c
index ffc3d6c..a0df817 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -53,10 +53,12 @@
 #else
 #include <stdio.h>
 #include <stdlib.h>
-#define mbedtls_free       free
+#define mbedtls_free      free
 #define mbedtls_calloc    calloc
-#define mbedtls_printf     printf
-#define mbedtls_snprintf   snprintf
+#define mbedtls_time      time
+#define mbedtls_time_t    time_t
+#define mbedtls_printf    printf
+#define mbedtls_snprintf  snprintf
 #endif
 
 #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
@@ -843,7 +845,7 @@
 static int x509_get_current_time( mbedtls_x509_time *now )
 {
     struct tm *lt;
-    time_t tt;
+    mbedtls_time_t tt;
     int ret = 0;
 
 #if defined(MBEDTLS_THREADING_C)
@@ -851,7 +853,7 @@
         return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
 #endif
 
-    tt = time( NULL );
+    tt = mbedtls_time( NULL );
     lt = gmtime( &tt );
 
     if( lt == NULL )