diff --git a/.github/issue_template.md b/.github/issue_template.md
index 5e9d83d..7c31353 100644
--- a/.github/issue_template.md
+++ b/.github/issue_template.md
@@ -38,4 +38,4 @@
 
 ## Question
 
-**Please first check for answers in the [Mbed TLS knowledge Base](https://tls.mbed.org/kb), and preferably file an issue in the [Mbed TLS support forum](https://tls.mbed.org/discussions)**  
+**Please first check for answers in the [Mbed TLS knowledge Base](https://tls.mbed.org/kb), and preferably file an issue in the [Mbed TLS support forum](https://forums.mbed.com/c/mbed-tls)**  
diff --git a/ChangeLog b/ChangeLog
index 981860b..35c8236 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,10 +3,46 @@
 = mbed TLS x.x.x branch released xxxx-xx-xx
 
 Bugfix
+   * Fix compilation error on C++, because of a variable named new.
+     Found and fixed by Hirotaka Niisato in #1783.
+   * Fix the inline assembly for the MPI multiply helper function for i386 and
+     i386 with SSE2. Found by László Langó. Fixes #1550
+   * Fix a memory leak in mbedtls_x509_csr_parse(), found by catenacyber,
+     Philippe Antoine. Fixes #1623.
+   * Clarify documentation for mbedtls_ssl_write() to include 0 as a valid
+     return value. Found by @davidwu2000. #839
+   * Fix the key_app_writer example which was writing a leading zero byte which
+     was creating an invalid ASN.1 tag. Found by Aryeh R. Fixes #1257.
+   * Remove unused headers included in x509.c. Found by Chris Hanson and fixed
+     by Brendan Shanks. Part of a fix for #992.
+   * Fix compilation error when MBEDTLS_ARC4_C is disabled and
+     MBEDTLS_CIPHER_NULL_CIPHER is enabled. Found by TrinityTonic in #1719.
+   * Added length checks to some TLS parsing functions. Found and fixed by
+     Philippe Antoine from Catena cyber. #1663.
+   * Fix namespacing in header files. Remove the `mbedtls` namespacing in
+     the `#include` in the header files. Resolves #857
+   * Fix compiler warning of 'use before initialisation' in
+     mbedtls_pk_parse_key(). Found by Martin Boye Petersen and fixed by Dawid
+     Drozd. #1098
+   * Fix decryption for zero length messages (which contain all padding) when a
+     CBC based ciphersuite is used together with Encrypt-then-MAC. Previously,
+     such a message was wrongly reported as an invalid record and therefore lead
+     to the connection being terminated. Seen most often with OpenSSL using
+     TLS 1.0. Reported by @kFYatek and by Conor Murphy on the forum. Fix
+     contributed by Espressif Systems. Fixes #1632
+   * Fail when receiving a TLS alert message with an invalid length, or invalid
+     zero-length messages when using TLS 1.2. Contributed by Espressif Systems.
+   * Fix ssl_client2 example to send application data with 0-length content
+     when the request_size argument is set to 0 as stated in the documentation.
+     Fixes #1833.
    * Correct the documentation for `mbedtls_ssl_get_session()`.
      This API has deep copy of the session, and the peer
      certificate is not lost. Fixes #926.
 
+Changes
+   * Change the shebang line in Perl scripts to look up perl in the PATH.
+     Contributed by fbrosson in #1533.
+
 = mbed TLS 2.7.4 branch released 2018-06-18
 
 Bugfix
diff --git a/README.md b/README.md
index a2c3c6f..ced36e1 100644
--- a/README.md
+++ b/README.md
@@ -211,7 +211,7 @@
 
 ### Making a Contribution
 
-1.  [Check for open issues](https://github.com/ARMmbed/mbedtls/issues) or [start a discussion](https://tls.mbed.org/discussions) around a feature idea or a bug.
+1.  [Check for open issues](https://github.com/ARMmbed/mbedtls/issues) or [start a discussion](https://forums.mbed.com/c/mbed-tls) around a feature idea or a bug.
 2.  Fork the [Mbed TLS repository on GitHub](https://github.com/ARMmbed/mbedtls) to start making your changes. As a general rule, you should use the "development" branch as a basis.
 3.  Write a test which shows that the bug was fixed or that the feature works as expected.
 4.  Send a pull request and bug us until it gets merged and published. Contributions may need some modifications, so work with us to get your change accepted. We will include your name in the ChangeLog :)
diff --git a/include/mbedtls/bn_mul.h b/include/mbedtls/bn_mul.h
index f4b2b56..b587317 100644
--- a/include/mbedtls/bn_mul.h
+++ b/include/mbedtls/bn_mul.h
@@ -49,7 +49,14 @@
 /* armcc5 --gnu defines __GNUC__ but doesn't support GNU's extended asm */
 #if defined(__GNUC__) && \
     ( !defined(__ARMCC_VERSION) || __ARMCC_VERSION >= 6000000 )
-#if defined(__i386__)
+
+/*
+ * Disable use of the i386 assembly code below if option -O0, to disable all
+ * compiler optimisations, is passed, detected with __OPTIMIZE__
+ * This is done as the number of registers used in the assembly code doesn't
+ * work with the -O0 option.
+ */
+#if defined(__i386__) && defined(__OPTIMIZE__)
 
 #define MULADDC_INIT                        \
     asm(                                    \
@@ -142,7 +149,7 @@
         "movl   %%esi, %3       \n\t"   \
         : "=m" (t), "=m" (c), "=m" (d), "=m" (s)        \
         : "m" (t), "m" (s), "m" (d), "m" (c), "m" (b)   \
-        : "eax", "ecx", "edx", "esi", "edi"             \
+        : "eax", "ebx", "ecx", "edx", "esi", "edi"      \
     );
 
 #else
@@ -154,7 +161,7 @@
         "movl   %%esi, %3       \n\t"   \
         : "=m" (t), "=m" (c), "=m" (d), "=m" (s)        \
         : "m" (t), "m" (s), "m" (d), "m" (c), "m" (b)   \
-        : "eax", "ecx", "edx", "esi", "edi"             \
+        : "eax", "ebx", "ecx", "edx", "esi", "edi"      \
     );
 #endif /* SSE2 */
 #endif /* i386 */
diff --git a/include/mbedtls/cipher.h b/include/mbedtls/cipher.h
index d1f4efe..1c453a1 100644
--- a/include/mbedtls/cipher.h
+++ b/include/mbedtls/cipher.h
@@ -43,7 +43,7 @@
 #define MBEDTLS_CIPHER_MODE_WITH_PADDING
 #endif
 
-#if defined(MBEDTLS_ARC4_C)
+#if defined(MBEDTLS_ARC4_C) || defined(MBEDTLS_CIPHER_NULL_CIPHER)
 #define MBEDTLS_CIPHER_MODE_STREAM
 #endif
 
diff --git a/include/mbedtls/cmac.h b/include/mbedtls/cmac.h
index 628c9da..24839a2 100644
--- a/include/mbedtls/cmac.h
+++ b/include/mbedtls/cmac.h
@@ -26,7 +26,7 @@
 #ifndef MBEDTLS_CMAC_H
 #define MBEDTLS_CMAC_H
 
-#include "mbedtls/cipher.h"
+#include "cipher.h"
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index c7ba174..8aee63f 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2818,7 +2818,7 @@
 /* \} name SECTION: Customisation configuration options */
 
 /* Target and application specific configurations */
-//#define YOTTA_CFG_MBEDTLS_TARGET_CONFIG_FILE "mbedtls/target_config.h"
+//#define YOTTA_CFG_MBEDTLS_TARGET_CONFIG_FILE "target_config.h"
 
 #if defined(TARGET_LIKE_MBED) && defined(YOTTA_CFG_MBEDTLS_TARGET_CONFIG_FILE)
 #include YOTTA_CFG_MBEDTLS_TARGET_CONFIG_FILE
diff --git a/include/mbedtls/ctr_drbg.h b/include/mbedtls/ctr_drbg.h
index 121575a..e554a0a 100644
--- a/include/mbedtls/ctr_drbg.h
+++ b/include/mbedtls/ctr_drbg.h
@@ -31,7 +31,7 @@
 #include "aes.h"
 
 #if defined(MBEDTLS_THREADING_C)
-#include "mbedtls/threading.h"
+#include "threading.h"
 #endif
 
 #define MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED        -0x0034  /**< The entropy source failed. */
diff --git a/include/mbedtls/hmac_drbg.h b/include/mbedtls/hmac_drbg.h
index e0821cf..2608de8 100644
--- a/include/mbedtls/hmac_drbg.h
+++ b/include/mbedtls/hmac_drbg.h
@@ -27,7 +27,7 @@
 #include "md.h"
 
 #if defined(MBEDTLS_THREADING_C)
-#include "mbedtls/threading.h"
+#include "threading.h"
 #endif
 
 /*
diff --git a/include/mbedtls/net.h b/include/mbedtls/net.h
index 28ae821..6c13b53 100644
--- a/include/mbedtls/net.h
+++ b/include/mbedtls/net.h
@@ -1,7 +1,7 @@
 /**
  * \file net.h
  *
- * \brief Deprecated header file that includes mbedtls/net_sockets.h
+ * \brief Deprecated header file that includes net_sockets.h
  *
  * \deprecated Superseded by mbedtls/net_sockets.h
  */
@@ -25,7 +25,7 @@
  */
 
 #if !defined(MBEDTLS_DEPRECATED_REMOVED)
-#include "mbedtls/net_sockets.h"
+#include "net_sockets.h"
 #if defined(MBEDTLS_DEPRECATED_WARNING)
 #warning "Deprecated header file: Superseded by mbedtls/net_sockets.h"
 #endif /* MBEDTLS_DEPRECATED_WARNING */
diff --git a/include/mbedtls/platform.h b/include/mbedtls/platform.h
index 2e21f03..7c2835b 100644
--- a/include/mbedtls/platform.h
+++ b/include/mbedtls/platform.h
@@ -31,7 +31,7 @@
 #endif
 
 #if defined(MBEDTLS_HAVE_TIME)
-#include "mbedtls/platform_time.h"
+#include "platform_time.h"
 #endif
 
 #ifdef __cplusplus
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 2de1460..c6e4532 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -53,7 +53,7 @@
 #endif
 
 #if defined(MBEDTLS_HAVE_TIME)
-#include "mbedtls/platform_time.h"
+#include "platform_time.h"
 #endif
 
 /*
@@ -2514,17 +2514,19 @@
  *                 or MBEDTLS_ERR_SSL_WANT_WRITE or MBEDTLS_ERR_SSL_WANT_READ,
  *                 or another negative error code.
  *
- * \note           If this function returns something other than a positive
- *                 value or MBEDTLS_ERR_SSL_WANT_READ/WRITE, the ssl context
- *                 becomes unusable, and you should either free it or call
- *                 \c mbedtls_ssl_session_reset() on it before re-using it for
- *                 a new connection; the current connection must be closed.
+ * \note           If this function returns something other than 0, a positive
+ *                 value or MBEDTLS_ERR_SSL_WANT_READ/WRITE, you must stop
+ *                 using the SSL context for reading or writing, and either
+ *                 free it or call \c mbedtls_ssl_session_reset() on it before
+ *                 re-using it for a new connection; the current connection
+ *                 must be closed.
  *
  * \note           When this function returns MBEDTLS_ERR_SSL_WANT_WRITE/READ,
  *                 it must be called later with the *same* arguments,
- *                 until it returns a positive value. When the function returns
- *                 MBEDTLS_ERR_SSL_WANT_WRITE there may be some partial
- *                 data in the output buffer, however this is not yet sent.
+ *                 until it returns a value greater that or equal to 0. When
+ *                 the function returns MBEDTLS_ERR_SSL_WANT_WRITE there may be
+ *                 some partial data in the output buffer, however this is not
+ *                 yet sent.
  *
  * \note           If the requested length is greater than the maximum
  *                 fragment length (either the built-in limit or the one set
@@ -2533,6 +2535,9 @@
  *                 - with DTLS, MBEDTLS_ERR_SSL_BAD_INPUT_DATA is returned.
  *                 \c mbedtls_ssl_get_max_frag_len() may be used to query the
  *                 active maximum fragment length.
+ *
+ * \note           Attempting to write 0 bytes will result in an empty TLS
+ *                 application record being sent.
  */
 int mbedtls_ssl_write( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len );
 
diff --git a/library/cipher.c b/library/cipher.c
index 7369f48..0d84ccf 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -56,10 +56,6 @@
 #define mbedtls_free   free
 #endif
 
-#if defined(MBEDTLS_ARC4_C) || defined(MBEDTLS_CIPHER_NULL_CIPHER)
-#define MBEDTLS_CIPHER_MODE_STREAM
-#endif
-
 /* Implementation that should never be optimized out by the compiler */
 static void mbedtls_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = (unsigned char*)v; while( n-- ) *p++ = 0;
diff --git a/library/cmac.c b/library/cmac.c
index a4a2106..9a73faa 100644
--- a/library/cmac.c
+++ b/library/cmac.c
@@ -832,6 +832,7 @@
         mbedtls_cipher_free( &ctx );
     }
 
+    ret = 0;
     goto exit;
 
 cleanup:
@@ -887,6 +888,7 @@
         if( verbose != 0 )
             mbedtls_printf( "passed\n" );
     }
+    ret = 0;
 
 exit:
     return( ret );
diff --git a/library/pkparse.c b/library/pkparse.c
index 26a8b70..a83bb01 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -1268,7 +1268,6 @@
         return( ret );
 #endif /* MBEDTLS_PKCS12_C || MBEDTLS_PKCS5_C */
 #else
-    ((void) ret);
     ((void) pwd);
     ((void) pwdlen);
 #endif /* MBEDTLS_PEM_PARSE_C */
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 15599c9..7e068c7 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -1250,14 +1250,14 @@
     size_t list_size;
     const unsigned char *p;
 
-    list_size = buf[0];
-    if( list_size + 1 != len )
+    if( len == 0 || (size_t)( buf[0] + 1 ) != len )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
         mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                         MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
+    list_size = buf[0];
 
     p = buf + 1;
     while( list_size > 0 )
@@ -2713,7 +2713,7 @@
      * therefore the buffer length at this point must be greater than that
      * regardless of the actual code path.
      */
-    if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n )
+    if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
         mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 14b5f29..db45ca2 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -97,6 +97,13 @@
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "parse ServerName extension" ) );
 
+    if( len < 2 )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                       MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
+        return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
+    }
     servername_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
     if( servername_list_size + 2 != len )
     {
@@ -107,7 +114,7 @@
     }
 
     p = buf + 2;
-    while( servername_list_size > 0 )
+    while( servername_list_size > 2 )
     {
         hostname_len = ( ( p[1] << 8 ) | p[2] );
         if( hostname_len + 3 > servername_list_size )
@@ -211,6 +218,12 @@
     mbedtls_md_type_t md_cur;
     mbedtls_pk_type_t sig_cur;
 
+    if ( len < 2 ) {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                       MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
+        return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
+    }
     sig_alg_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
     if( sig_alg_list_size + 2 != len ||
         sig_alg_list_size % 2 != 0 )
@@ -279,6 +292,12 @@
     const unsigned char *p;
     const mbedtls_ecp_curve_info *curve_info, **curves;
 
+    if ( len < 2 ) {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                       MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
+        return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
+    }
     list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
     if( list_size + 2 != len ||
         list_size % 2 != 0 )
@@ -338,14 +357,14 @@
     size_t list_size;
     const unsigned char *p;
 
-    list_size = buf[0];
-    if( list_size + 1 != len )
+    if( len == 0 || (size_t)( buf[0] + 1 ) != len )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
         mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                         MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
+    list_size = buf[0];
 
     p = buf + 1;
     while( list_size > 0 )
@@ -1662,10 +1681,16 @@
 
         while( ext_len != 0 )
         {
-            unsigned int ext_id   = ( ( ext[0] <<  8 )
-                                    | ( ext[1]       ) );
-            unsigned int ext_size = ( ( ext[2] <<  8 )
-                                    | ( ext[3]       ) );
+            unsigned int ext_id;
+            unsigned int ext_size;
+            if ( ext_len < 4 ) {
+                MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                               MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
+                return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
+            }
+            ext_id   = ( ( ext[0] <<  8 ) | ( ext[1] ) );
+            ext_size = ( ( ext[2] <<  8 ) | ( ext[3] ) );
 
             if( ext_size + 4 > ext_len )
             {
@@ -3305,6 +3330,10 @@
     defined(MBEDTLS_SSL_PROTO_TLS1_2)
     if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
     {
+        if ( p + 2 > end ) {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
+            return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
+        }
         if( *p++ != ( ( len >> 8 ) & 0xFF ) ||
             *p++ != ( ( len      ) & 0xFF ) )
         {
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 6d7ad33..c19a26d 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -1153,6 +1153,9 @@
          * other_secret already set by the ClientKeyExchange message,
          * and is 48 bytes long
          */
+        if( end - p < 2 )
+            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
         *p++ = 0;
         *p++ = 48;
         p += 48;
@@ -1902,27 +1905,27 @@
              * and fake check up to 256 bytes of padding
              */
             size_t pad_count = 0, real_count = 1;
-            size_t padding_idx = ssl->in_msglen - padlen - 1;
+            size_t padding_idx = ssl->in_msglen - padlen;
 
             /*
              * Padding is guaranteed to be incorrect if:
-             *   1. padlen >= ssl->in_msglen
+             *   1. padlen > ssl->in_msglen
              *
-             *   2. padding_idx >= MBEDTLS_SSL_MAX_CONTENT_LEN +
+             *   2. padding_idx > MBEDTLS_SSL_MAX_CONTENT_LEN +
              *                     ssl->transform_in->maclen
              *
              * In both cases we reset padding_idx to a safe value (0) to
              * prevent out-of-buffer reads.
              */
-            correct &= ( ssl->in_msglen >= padlen + 1 );
-            correct &= ( padding_idx < MBEDTLS_SSL_MAX_CONTENT_LEN +
+            correct &= ( padlen <= ssl->in_msglen );
+            correct &= ( padding_idx <= MBEDTLS_SSL_MAX_CONTENT_LEN +
                                        ssl->transform_in->maclen );
 
             padding_idx *= correct;
 
-            for( i = 1; i <= 256; i++ )
+            for( i = 0; i < 256; i++ )
             {
-                real_count &= ( i <= padlen );
+                real_count &= ( i < padlen );
                 pad_count += real_count *
                              ( ssl->in_msg[padding_idx + i] == padlen - 1 );
             }
@@ -2055,6 +2058,16 @@
 
     if( ssl->in_msglen == 0 )
     {
+#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
+        if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3
+            && ssl->in_msgtype != MBEDTLS_SSL_MSG_APPLICATION_DATA )
+        {
+            /* TLS v1.2 explicitly disallows zero-length messages which are not application data */
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid zero-length message type: %d", ssl->in_msgtype ) );
+            return( MBEDTLS_ERR_SSL_INVALID_RECORD );
+        }
+#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
+
         ssl->nb_zero++;
 
         /*
@@ -4127,6 +4140,16 @@
 
     if( ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT )
     {
+        if( ssl->in_msglen != 2 )
+        {
+            /* Note: Standard allows for more than one 2 byte alert
+               to be packed in a single message, but Mbed TLS doesn't
+               currently support this. */
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid alert message, len: %d",
+                           ssl->in_msglen ) );
+            return( MBEDTLS_ERR_SSL_INVALID_RECORD );
+        }
+
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "got an alert message, type: [%d:%d]",
                        ssl->in_msg[0], ssl->in_msg[1] ) );
 
@@ -4550,6 +4573,12 @@
 
     while( i < ssl->in_hslen )
     {
+        if ( i + 3 > ssl->in_hslen ) {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                           MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
+            return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
+        }
         if( ssl->in_msg[i] != 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
@@ -6017,27 +6046,27 @@
                                 mbedtls_x509_crt *cert,
                                 mbedtls_pk_context *key )
 {
-    mbedtls_ssl_key_cert *new;
+    mbedtls_ssl_key_cert *new_cert;
 
-    new = mbedtls_calloc( 1, sizeof( mbedtls_ssl_key_cert ) );
-    if( new == NULL )
+    new_cert = mbedtls_calloc( 1, sizeof( mbedtls_ssl_key_cert ) );
+    if( new_cert == NULL )
         return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
 
-    new->cert = cert;
-    new->key  = key;
-    new->next = NULL;
+    new_cert->cert = cert;
+    new_cert->key  = key;
+    new_cert->next = NULL;
 
     /* Update head is the list was null, else add to the end */
     if( *head == NULL )
     {
-        *head = new;
+        *head = new_cert;
     }
     else
     {
         mbedtls_ssl_key_cert *cur = *head;
         while( cur->next != NULL )
             cur = cur->next;
-        cur->next = new;
+        cur->next = new_cert;
     }
 
     return( 0 );
@@ -7137,8 +7166,16 @@
 }
 
 /*
- * Send application data to be encrypted by the SSL layer,
- * taking care of max fragment length and buffer size
+ * Send application data to be encrypted by the SSL layer, taking care of max
+ * fragment length and buffer size.
+ *
+ * According to RFC 5246 Section 6.2.1:
+ *
+ *      Zero-length fragments of Application data MAY be sent as they are
+ *      potentially useful as a traffic analysis countermeasure.
+ *
+ * Therefore, it is possible that the input message length is 0 and the
+ * corresponding return code is 0 on success.
  */
 static int ssl_write_real( mbedtls_ssl_context *ssl,
                            const unsigned char *buf, size_t len )
@@ -7166,6 +7203,12 @@
 
     if( ssl->out_left != 0 )
     {
+        /*
+         * The user has previously tried to send the data and
+         * MBEDTLS_ERR_SSL_WANT_WRITE or the message was only partially
+         * written. In this case, we expect the high-level write function
+         * (e.g. mbedtls_ssl_write()) to be called with the same parameters
+         */
         if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flush_output", ret );
@@ -7174,6 +7217,11 @@
     }
     else
     {
+        /*
+         * The user is trying to send a message the first time, so we need to
+         * copy the data into the internal buffers and setup the data structure
+         * to keep track of partial writes
+         */
         ssl->out_msglen  = len;
         ssl->out_msgtype = MBEDTLS_SSL_MSG_APPLICATION_DATA;
         memcpy( ssl->out_msg, buf, len );
diff --git a/library/x509.c b/library/x509.c
index 371d6da..264c7fb 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -70,15 +70,6 @@
 #include <time.h>
 #endif
 
-#if defined(MBEDTLS_FS_IO)
-#include <stdio.h>
-#if !defined(_WIN32)
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <dirent.h>
-#endif
-#endif
-
 #define CHECK(code) if( ( ret = code ) != 0 ){ return( ret ); }
 #define CHECK_RANGE(min, max, val) if( val < min || val > max ){ return( ret ); }
 
diff --git a/library/x509_csr.c b/library/x509_csr.c
index 26a06db..779098d 100644
--- a/library/x509_csr.c
+++ b/library/x509_csr.c
@@ -278,34 +278,25 @@
         return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
 
 #if defined(MBEDTLS_PEM_PARSE_C)
-    mbedtls_pem_init( &pem );
-
     /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
-    if( buf[buflen - 1] != '\0' )
-        ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
-    else
+    if( buf[buflen - 1] == '\0' )
+    {
+        mbedtls_pem_init( &pem );
         ret = mbedtls_pem_read_buffer( &pem,
                                "-----BEGIN CERTIFICATE REQUEST-----",
                                "-----END CERTIFICATE REQUEST-----",
                                buf, NULL, 0, &use_len );
 
-    if( ret == 0 )
-    {
-        /*
-         * Was PEM encoded, parse the result
-         */
-        if( ( ret = mbedtls_x509_csr_parse_der( csr, pem.buf, pem.buflen ) ) != 0 )
-            return( ret );
+        if( ret == 0 )
+            /*
+             * Was PEM encoded, parse the result
+             */
+            ret = mbedtls_x509_csr_parse_der( csr, pem.buf, pem.buflen );
 
         mbedtls_pem_free( &pem );
-        return( 0 );
+        if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
+            return( ret );
     }
-    else if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
-    {
-        mbedtls_pem_free( &pem );
-        return( ret );
-    }
-    else
 #endif /* MBEDTLS_PEM_PARSE_C */
     return( mbedtls_x509_csr_parse_der( csr, buf, buflen ) );
 }
diff --git a/programs/aes/aescrypt2.c b/programs/aes/aescrypt2.c
index 4acf38d..c727f93 100644
--- a/programs/aes/aescrypt2.c
+++ b/programs/aes/aescrypt2.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #include "mbedtls/aes.h"
 #include "mbedtls/md.h"
@@ -71,7 +74,8 @@
 #else
 int main( int argc, char *argv[] )
 {
-    int ret = 1;
+    int ret = 0;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
 
     unsigned int i, n;
     int mode, lastn;
@@ -429,7 +433,7 @@
         }
     }
 
-    ret = 0;
+    exit_code = MBEDTLS_EXIT_SUCCESS;
 
 exit:
     if( fin )
@@ -452,6 +456,6 @@
     mbedtls_aes_free( &aes_ctx );
     mbedtls_md_free( &sha_ctx );
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_AES_C && MBEDTLS_SHA256_C && MBEDTLS_FS_IO */
diff --git a/programs/aes/crypt_and_hash.c b/programs/aes/crypt_and_hash.c
index 0e272eb..99d30c9 100644
--- a/programs/aes/crypt_and_hash.c
+++ b/programs/aes/crypt_and_hash.c
@@ -30,9 +30,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_CIPHER_C) && defined(MBEDTLS_MD_C) && \
  defined(MBEDTLS_FS_IO)
@@ -74,6 +77,7 @@
 int main( int argc, char *argv[] )
 {
     int ret = 1, i, n;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     int mode;
     size_t keylen, ilen, olen;
     FILE *fkey, *fin = NULL, *fout = NULL;
@@ -526,7 +530,7 @@
         }
     }
 
-    ret = 0;
+    exit_code = MBEDTLS_EXIT_SUCCESS;
 
 exit:
     if( fin )
@@ -549,6 +553,6 @@
     mbedtls_cipher_free( &cipher_ctx );
     mbedtls_md_free( &md_ctx );
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_CIPHER_C && MBEDTLS_MD_C && MBEDTLS_FS_IO */
diff --git a/programs/hash/generic_sum.c b/programs/hash/generic_sum.c
index d1e81d4..bbe8d92 100644
--- a/programs/hash/generic_sum.c
+++ b/programs/hash/generic_sum.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_MD_C) && defined(MBEDTLS_FS_IO)
 #include "mbedtls/md.h"
@@ -169,7 +172,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret, i;
+    int ret = 1, i;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     const mbedtls_md_info_t *md_info;
     mbedtls_md_context_t md_ctx;
 
@@ -196,7 +200,7 @@
         fflush( stdout ); getchar();
 #endif
 
-        return( 1 );
+        return( exit_code );
     }
 
     /*
@@ -206,12 +210,12 @@
     if( md_info == NULL )
     {
         mbedtls_fprintf( stderr, "Message Digest '%s' not found\n", argv[1] );
-        return( 1 );
+        return( exit_code );
     }
     if( mbedtls_md_setup( &md_ctx, md_info, 0 ) )
     {
         mbedtls_fprintf( stderr, "Failed to initialize context.\n" );
-        return( 1 );
+        return( exit_code );
     }
 
     ret = 0;
@@ -224,9 +228,12 @@
     for( i = 2; i < argc; i++ )
         ret |= generic_print( md_info, argv[i] );
 
+    if ( ret == 0 )
+        exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     mbedtls_md_free( &md_ctx );
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_MD_C && MBEDTLS_FS_IO */
diff --git a/programs/pkey/dh_client.c b/programs/pkey/dh_client.c
index 0978408..3dadf48 100644
--- a/programs/pkey/dh_client.c
+++ b/programs/pkey/dh_client.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#define mbedtls_time_t     time_t
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define mbedtls_time_t          time_t
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_AES_C) && defined(MBEDTLS_DHM_C) && \
     defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_NET_C) && \
@@ -71,7 +74,8 @@
 {
     FILE *f;
 
-    int ret;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     size_t n, buflen;
     mbedtls_net_context server_fd;
 
@@ -115,7 +119,6 @@
 
     if( ( f = fopen( "rsa_pub.txt", "rb" ) ) == NULL )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Could not open rsa_pub.txt\n" \
                 "  ! Please run rsa_genkey first\n\n" );
         goto exit;
@@ -191,7 +194,6 @@
 
     if( dhm.len < 64 || dhm.len > 512 )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Invalid DHM modulus size\n\n" );
         goto exit;
     }
@@ -207,7 +209,6 @@
 
     if( ( n = (size_t) ( end - p ) ) != rsa.len )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Invalid RSA signature size\n\n" );
         goto exit;
     }
@@ -286,6 +287,8 @@
     buf[16] = '\0';
     mbedtls_printf( "\n  . Plaintext is \"%s\"\n\n", (char *) buf );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
     mbedtls_net_free( &server_fd );
@@ -301,7 +304,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_AES_C && MBEDTLS_DHM_C && MBEDTLS_ENTROPY_C &&
           MBEDTLS_NET_C && MBEDTLS_RSA_C && MBEDTLS_SHA256_C &&
diff --git a/programs/pkey/dh_genprime.c b/programs/pkey/dh_genprime.c
index 84a94a1..dbe9153 100644
--- a/programs/pkey/dh_genprime.c
+++ b/programs/pkey/dh_genprime.c
@@ -30,9 +30,11 @@
 #else
 #include <stdio.h>
 #include <stdlib.h>
-#define mbedtls_printf     printf
-#define mbedtls_time_t     time_t
-#endif
+#define mbedtls_printf          printf
+#define mbedtls_time_t          time_t
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) ||   \
     !defined(MBEDTLS_FS_IO) || !defined(MBEDTLS_CTR_DRBG_C) ||     \
@@ -69,6 +71,7 @@
 int main( int argc, char **argv )
 {
     int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_mpi G, P, Q;
     mbedtls_entropy_context entropy;
     mbedtls_ctr_drbg_context ctr_drbg;
@@ -86,7 +89,7 @@
     {
     usage:
         mbedtls_printf( USAGE );
-        return( 1 );
+        return( exit_code );
     }
 
     for( i = 1; i < argc; i++ )
@@ -164,7 +167,6 @@
 
     if( ( fout = fopen( "dh_prime.txt", "wb+" ) ) == NULL )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Could not create dh_prime.txt\n\n" );
         goto exit;
     }
@@ -180,6 +182,8 @@
     mbedtls_printf( " ok\n\n" );
     fclose( fout );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
     mbedtls_mpi_free( &G ); mbedtls_mpi_free( &P ); mbedtls_mpi_free( &Q );
@@ -191,7 +195,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_FS_IO &&
           MBEDTLS_CTR_DRBG_C && MBEDTLS_GENPRIME */
diff --git a/programs/pkey/dh_server.c b/programs/pkey/dh_server.c
index 4304231..c4e2c39 100644
--- a/programs/pkey/dh_server.c
+++ b/programs/pkey/dh_server.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#define mbedtls_time_t     time_t
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define mbedtls_time_t          time_t
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_AES_C) && defined(MBEDTLS_DHM_C) && \
     defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_NET_C) && \
@@ -71,7 +74,8 @@
 {
     FILE *f;
 
-    int ret;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     size_t n, buflen;
     mbedtls_net_context listen_fd, client_fd;
 
@@ -121,7 +125,6 @@
 
     if( ( f = fopen( "rsa_priv.txt", "rb" ) ) == NULL )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Could not open rsa_priv.txt\n" \
                 "  ! Please run rsa_genkey first\n\n" );
         goto exit;
@@ -164,7 +167,6 @@
 
     if( ( f = fopen( "dh_prime.txt", "rb" ) ) == NULL )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Could not open dh_prime.txt\n" \
                 "  ! Please run dh_genprime first\n\n" );
         goto exit;
@@ -304,6 +306,8 @@
 
     mbedtls_printf( "\n\n" );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
     mbedtls_mpi_free( &N ); mbedtls_mpi_free( &P ); mbedtls_mpi_free( &Q );
@@ -323,7 +327,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_AES_C && MBEDTLS_DHM_C && MBEDTLS_ENTROPY_C &&
           MBEDTLS_NET_C && MBEDTLS_RSA_C && MBEDTLS_SHA256_C &&
diff --git a/programs/pkey/ecdh_curve25519.c b/programs/pkey/ecdh_curve25519.c
index e7ead9a..5db0408 100644
--- a/programs/pkey/ecdh_curve25519.c
+++ b/programs/pkey/ecdh_curve25519.c
@@ -29,8 +29,11 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_ECDH_C) || \
     !defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) || \
@@ -51,7 +54,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_ecdh_context ctx_cli, ctx_srv;
     mbedtls_entropy_context entropy;
     mbedtls_ctr_drbg_context ctr_drbg;
@@ -218,6 +222,7 @@
 
     mbedtls_printf( " ok\n" );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
 
 exit:
 
@@ -231,7 +236,7 @@
     mbedtls_ctr_drbg_free( &ctr_drbg );
     mbedtls_entropy_free( &entropy );
 
-    return( ret != 0 );
+    return( exit_code );
 }
 #endif /* MBEDTLS_ECDH_C && MBEDTLS_ECP_DP_CURVE25519_ENABLED &&
           MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */
diff --git a/programs/pkey/ecdsa.c b/programs/pkey/ecdsa.c
index b474060..c653df9 100644
--- a/programs/pkey/ecdsa.c
+++ b/programs/pkey/ecdsa.c
@@ -29,8 +29,11 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_ECDSA_C) && \
     defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_CTR_DRBG_C)
@@ -98,7 +101,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_ecdsa_context ctx_sign, ctx_verify;
     mbedtls_entropy_context entropy;
     mbedtls_ctr_drbg_context ctr_drbg;
@@ -115,7 +119,6 @@
 
     memset( sig, 0, sizeof( sig ) );
     memset( message, 0x25, sizeof( message ) );
-    ret = 1;
 
     if( argc != 1 )
     {
@@ -213,8 +216,6 @@
         goto exit;
     }
 
-    ret = 0;
-
     /*
      * Verify signature
      */
@@ -231,6 +232,8 @@
 
     mbedtls_printf( " ok\n" );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
 #if defined(_WIN32)
@@ -243,7 +246,7 @@
     mbedtls_ctr_drbg_free( &ctr_drbg );
     mbedtls_entropy_free( &entropy );
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C &&
           ECPARAMS */
diff --git a/programs/pkey/gen_key.c b/programs/pkey/gen_key.c
index a7f5c90..f01bf5f 100644
--- a/programs/pkey/gen_key.c
+++ b/programs/pkey/gen_key.c
@@ -29,8 +29,11 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_PK_WRITE_C) && defined(MBEDTLS_FS_IO) && \
     defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_CTR_DRBG_C)
@@ -186,7 +189,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret = 0;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_pk_context key;
     char buf[1024];
     int i;
@@ -214,7 +218,6 @@
     if( argc == 0 )
     {
     usage:
-        ret = 1;
         mbedtls_printf( USAGE );
 #if defined(MBEDTLS_ECP_C)
         mbedtls_printf( " available ec_curve values:\n" );
@@ -222,7 +225,7 @@
         mbedtls_printf( "    %s (default)\n", curve_info->name );
         while( ( ++curve_info )->name != NULL )
             mbedtls_printf( "    %s\n", curve_info->name );
-#endif
+#endif /* MBEDTLS_ECP_C */
         goto exit;
     }
 
@@ -411,9 +414,11 @@
 
     mbedtls_printf( " ok\n" );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
-    if( ret != 0 && ret != 1)
+    if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
 #ifdef MBEDTLS_ERROR_C
         mbedtls_strerror( ret, buf, sizeof( buf ) );
@@ -436,7 +441,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_PK_WRITE_C && MBEDTLS_PEM_WRITE_C && MBEDTLS_FS_IO &&
         * MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */
diff --git a/programs/pkey/key_app.c b/programs/pkey/key_app.c
index f1b548d..7a4cb39 100644
--- a/programs/pkey/key_app.c
+++ b/programs/pkey/key_app.c
@@ -29,8 +29,11 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_BIGNUM_C) && \
     defined(MBEDTLS_PK_PARSE_C) && defined(MBEDTLS_FS_IO)
@@ -83,7 +86,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret = 0;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     char buf[1024];
     int i;
     char *p, *q;
@@ -283,10 +287,12 @@
     else
         goto usage;
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
 #if defined(MBEDTLS_ERROR_C)
-    if( ret != 0 )
+    if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
         mbedtls_strerror( ret, buf, sizeof(buf) );
         mbedtls_printf( "  !  Last error was: %s\n", buf );
@@ -303,6 +309,6 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_PK_PARSE_C && MBEDTLS_FS_IO */
diff --git a/programs/pkey/key_app_writer.c b/programs/pkey/key_app_writer.c
index 52b0f8e..13602c2 100644
--- a/programs/pkey/key_app_writer.c
+++ b/programs/pkey/key_app_writer.c
@@ -29,8 +29,11 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_PK_WRITE_C) && defined(MBEDTLS_FS_IO)
 #include "mbedtls/error.h"
@@ -128,7 +131,7 @@
             return( ret );
 
         len = ret;
-        c = output_buf + sizeof(output_buf) - len - 1;
+        c = output_buf + sizeof(output_buf) - len;
     }
 
     if( ( f = fopen( output_file, "w" ) ) == NULL )
@@ -189,7 +192,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret = 0;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     char buf[1024];
     int i;
     char *p, *q;
@@ -210,7 +214,6 @@
     if( argc == 0 )
     {
     usage:
-        ret = 1;
         mbedtls_printf( USAGE );
         goto exit;
     }
@@ -403,9 +406,11 @@
         write_private_key( &key, opt.output_file );
     }
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
-    if( ret != 0 && ret != 1)
+    if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
 #ifdef MBEDTLS_ERROR_C
         mbedtls_strerror( ret, buf, sizeof( buf ) );
@@ -426,6 +431,6 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_PK_WRITE_C && MBEDTLS_FS_IO */
diff --git a/programs/pkey/mpi_demo.c b/programs/pkey/mpi_demo.c
index afe8957..365bdc4 100644
--- a/programs/pkey/mpi_demo.c
+++ b/programs/pkey/mpi_demo.c
@@ -29,8 +29,11 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_FS_IO)
 #include "mbedtls/bignum.h"
@@ -47,7 +50,8 @@
 #else
 int main( void )
 {
-    int ret;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_mpi E, P, Q, N, H, D, X, Y, Z;
 
     mbedtls_mpi_init( &E ); mbedtls_mpi_init( &P ); mbedtls_mpi_init( &Q ); mbedtls_mpi_init( &N );
@@ -88,15 +92,16 @@
     MBEDTLS_MPI_CHK( mbedtls_mpi_write_file( "  Z (decrypted)  = Y^D mod N = ", &Z, 10, NULL ) );
     mbedtls_printf( "\n" );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 cleanup:
     mbedtls_mpi_free( &E ); mbedtls_mpi_free( &P ); mbedtls_mpi_free( &Q ); mbedtls_mpi_free( &N );
     mbedtls_mpi_free( &H ); mbedtls_mpi_free( &D ); mbedtls_mpi_free( &X ); mbedtls_mpi_free( &Y );
     mbedtls_mpi_free( &Z );
 
-    if( ret != 0 )
+    if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
         mbedtls_printf( "\nAn error occurred.\n" );
-        ret = 1;
     }
 
 #if defined(_WIN32)
@@ -104,6 +109,6 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_FS_IO */
diff --git a/programs/pkey/pk_decrypt.c b/programs/pkey/pk_decrypt.c
index 32fbc75..00bd71e 100644
--- a/programs/pkey/pk_decrypt.c
+++ b/programs/pkey/pk_decrypt.c
@@ -29,8 +29,11 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_PK_PARSE_C) && \
     defined(MBEDTLS_FS_IO) && defined(MBEDTLS_ENTROPY_C) && \
@@ -59,7 +62,8 @@
 int main( int argc, char *argv[] )
 {
     FILE *f;
-    int ret, c;
+    int ret = 1, c;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     size_t i, olen = 0;
     mbedtls_pk_context pk;
     mbedtls_entropy_context entropy;
@@ -71,7 +75,6 @@
 
     mbedtls_ctr_drbg_init( &ctr_drbg );
     memset(result, 0, sizeof( result ) );
-    ret = 1;
 
     if( argc != 2 )
     {
@@ -110,8 +113,6 @@
     /*
      * Extract the RSA encrypted value from the text file
      */
-    ret = 1;
-
     if( ( f = fopen( "result-enc.txt", "rb" ) ) == NULL )
     {
         mbedtls_printf( "\n  ! Could not open %s\n\n", "result-enc.txt" );
@@ -143,14 +144,14 @@
 
     mbedtls_printf( "The decrypted result is: '%s'\n\n", result );
 
-    ret = 0;
+    exit_code = MBEDTLS_EXIT_SUCCESS;
 
 exit:
     mbedtls_ctr_drbg_free( &ctr_drbg );
     mbedtls_entropy_free( &entropy );
 
 #if defined(MBEDTLS_ERROR_C)
-    if( ret != 0 )
+    if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
         mbedtls_strerror( ret, (char *) buf, sizeof(buf) );
         mbedtls_printf( "  !  Last error was: %s\n", buf );
@@ -162,7 +163,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_PK_PARSE_C && MBEDTLS_FS_IO &&
           MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */
diff --git a/programs/pkey/pk_encrypt.c b/programs/pkey/pk_encrypt.c
index 7ca9d5a..400619c 100644
--- a/programs/pkey/pk_encrypt.c
+++ b/programs/pkey/pk_encrypt.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_PK_PARSE_C) && \
     defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_FS_IO) && \
@@ -59,7 +62,8 @@
 int main( int argc, char *argv[] )
 {
     FILE *f;
-    int ret;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     size_t i, olen = 0;
     mbedtls_pk_context pk;
     mbedtls_entropy_context entropy;
@@ -68,7 +72,6 @@
     unsigned char buf[512];
     const char *pers = "mbedtls_pk_encrypt";
 
-    ret = 1;
     mbedtls_ctr_drbg_init( &ctr_drbg );
 
     if( argc != 3 )
@@ -132,7 +135,6 @@
      */
     if( ( f = fopen( "result-enc.txt", "wb+" ) ) == NULL )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Could not create %s\n\n", "result-enc.txt" );
         goto exit;
     }
@@ -145,12 +147,14 @@
 
     mbedtls_printf( "\n  . Done (created \"%s\")\n\n", "result-enc.txt" );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     mbedtls_ctr_drbg_free( &ctr_drbg );
     mbedtls_entropy_free( &entropy );
 
 #if defined(MBEDTLS_ERROR_C)
-    if( ret != 0 )
+    if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
         mbedtls_strerror( ret, (char *) buf, sizeof(buf) );
         mbedtls_printf( "  !  Last error was: %s\n", buf );
@@ -162,7 +166,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_PK_PARSE_C && MBEDTLS_ENTROPY_C &&
           MBEDTLS_FS_IO && MBEDTLS_CTR_DRBG_C */
diff --git a/programs/pkey/pk_sign.c b/programs/pkey/pk_sign.c
index 55df95e..7ec4675 100644
--- a/programs/pkey/pk_sign.c
+++ b/programs/pkey/pk_sign.c
@@ -30,9 +30,11 @@
 #else
 #include <stdio.h>
 #include <stdlib.h>
-#define mbedtls_snprintf   snprintf
-#define mbedtls_printf     printf
-#endif
+#define mbedtls_snprintf        snprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) ||  \
     !defined(MBEDTLS_SHA256_C) || !defined(MBEDTLS_MD_C) || \
@@ -61,6 +63,7 @@
 {
     FILE *f;
     int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_pk_context pk;
     mbedtls_entropy_context entropy;
     mbedtls_ctr_drbg_context ctr_drbg;
@@ -134,14 +137,12 @@
 
     if( ( f = fopen( filename, "wb+" ) ) == NULL )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Could not create %s\n\n", filename );
         goto exit;
     }
 
     if( fwrite( buf, 1, olen, f ) != olen )
     {
-        ret = 1;
         mbedtls_printf( "failed\n  ! fwrite failed\n\n" );
         fclose( f );
         goto exit;
@@ -151,13 +152,15 @@
 
     mbedtls_printf( "\n  . Done (created \"%s\")\n\n", filename );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     mbedtls_pk_free( &pk );
     mbedtls_ctr_drbg_free( &ctr_drbg );
     mbedtls_entropy_free( &entropy );
 
 #if defined(MBEDTLS_ERROR_C)
-    if( ret != 0 )
+    if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
         mbedtls_strerror( ret, (char *) buf, sizeof(buf) );
         mbedtls_printf( "  !  Last error was: %s\n", buf );
@@ -169,7 +172,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret ? EXIT_FAILURE : EXIT_SUCCESS );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C &&
           MBEDTLS_SHA256_C && MBEDTLS_PK_PARSE_C && MBEDTLS_FS_IO &&
diff --git a/programs/pkey/pk_verify.c b/programs/pkey/pk_verify.c
index d35d17f..3c7709f 100644
--- a/programs/pkey/pk_verify.c
+++ b/programs/pkey/pk_verify.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_snprintf   snprintf
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_snprintf        snprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_MD_C) || \
     !defined(MBEDTLS_SHA256_C) || !defined(MBEDTLS_PK_PARSE_C) ||   \
@@ -56,6 +59,7 @@
 {
     FILE *f;
     int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     size_t i;
     mbedtls_pk_context pk;
     unsigned char hash[32];
@@ -87,7 +91,6 @@
     /*
      * Extract the signature from the file
      */
-    ret = 1;
     mbedtls_snprintf( filename, sizeof(filename), "%s.sig", argv[2] );
 
     if( ( f = fopen( filename, "rb" ) ) == NULL )
@@ -125,13 +128,13 @@
 
     mbedtls_printf( "\n  . OK (the signature is valid)\n\n" );
 
-    ret = 0;
+    exit_code = MBEDTLS_EXIT_SUCCESS;
 
 exit:
     mbedtls_pk_free( &pk );
 
 #if defined(MBEDTLS_ERROR_C)
-    if( ret != 0 )
+    if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
         mbedtls_strerror( ret, (char *) buf, sizeof(buf) );
         mbedtls_printf( "  !  Last error was: %s\n", buf );
@@ -143,7 +146,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_SHA256_C &&
           MBEDTLS_PK_PARSE_C && MBEDTLS_FS_IO */
diff --git a/programs/pkey/rsa_decrypt.c b/programs/pkey/rsa_decrypt.c
index 2da3fbf..0a252d2 100644
--- a/programs/pkey/rsa_decrypt.c
+++ b/programs/pkey/rsa_decrypt.c
@@ -30,11 +30,11 @@
 #else
 #include <stdio.h>
 #include <stdlib.h>
-#define mbedtls_printf     printf
-#define mbedtls_exit       exit
+#define mbedtls_printf       printf
+#define mbedtls_exit         exit
 #define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
 #define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
-#endif
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_RSA_C) && \
     defined(MBEDTLS_FS_IO) && defined(MBEDTLS_ENTROPY_C) && \
@@ -61,7 +61,9 @@
 int main( int argc, char *argv[] )
 {
     FILE *f;
-    int return_val, exit_val, c;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
+    int c;
     size_t i;
     mbedtls_rsa_context rsa;
     mbedtls_mpi N, P, Q, D, E, DP, DQ, QP;
@@ -73,7 +75,6 @@
     ((void) argv);
 
     memset(result, 0, sizeof( result ) );
-    exit_val = MBEDTLS_EXIT_SUCCESS;
 
     if( argc != 1 )
     {
@@ -83,7 +84,7 @@
         mbedtls_printf( "\n" );
 #endif
 
-        mbedtls_exit( MBEDTLS_EXIT_FAILURE );
+        mbedtls_exit( exit_code );
     }
 
     mbedtls_printf( "\n  . Seeding the random number generator..." );
@@ -96,14 +97,13 @@
     mbedtls_mpi_init( &D ); mbedtls_mpi_init( &E ); mbedtls_mpi_init( &DP );
     mbedtls_mpi_init( &DQ ); mbedtls_mpi_init( &QP );
 
-    return_val = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func,
+    ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func,
                                         &entropy, (const unsigned char *) pers,
                                         strlen( pers ) );
-    if( return_val != 0 )
+    if( ret != 0 )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( " failed\n  ! mbedtls_ctr_drbg_seed returned %d\n",
-                        return_val );
+                        ret );
         goto exit;
     }
 
@@ -112,40 +112,38 @@
 
     if( ( f = fopen( "rsa_priv.txt", "rb" ) ) == NULL )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( " failed\n  ! Could not open rsa_priv.txt\n" \
                 "  ! Please run rsa_genkey first\n\n" );
         goto exit;
     }
 
-    if( ( return_val = mbedtls_mpi_read_file( &N , 16, f ) )  != 0 ||
-        ( return_val = mbedtls_mpi_read_file( &E , 16, f ) )  != 0 ||
-        ( return_val = mbedtls_mpi_read_file( &D , 16, f ) )  != 0 ||
-        ( return_val = mbedtls_mpi_read_file( &P , 16, f ) )  != 0 ||
-        ( return_val = mbedtls_mpi_read_file( &Q , 16, f ) )  != 0 ||
-        ( return_val = mbedtls_mpi_read_file( &DP , 16, f ) ) != 0 ||
-        ( return_val = mbedtls_mpi_read_file( &DQ , 16, f ) ) != 0 ||
-        ( return_val = mbedtls_mpi_read_file( &QP , 16, f ) ) != 0 )
+    if( ( ret = mbedtls_mpi_read_file( &N , 16, f ) )  != 0 ||
+        ( ret = mbedtls_mpi_read_file( &E , 16, f ) )  != 0 ||
+        ( ret = mbedtls_mpi_read_file( &D , 16, f ) )  != 0 ||
+        ( ret = mbedtls_mpi_read_file( &P , 16, f ) )  != 0 ||
+        ( ret = mbedtls_mpi_read_file( &Q , 16, f ) )  != 0 ||
+        ( ret = mbedtls_mpi_read_file( &DP , 16, f ) ) != 0 ||
+        ( ret = mbedtls_mpi_read_file( &DQ , 16, f ) ) != 0 ||
+        ( ret = mbedtls_mpi_read_file( &QP , 16, f ) ) != 0 )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( " failed\n  ! mbedtls_mpi_read_file returned %d\n\n",
-                        return_val );
+                        ret );
         fclose( f );
         goto exit;
     }
     fclose( f );
 
-    if( ( return_val = mbedtls_rsa_import( &rsa, &N, &P, &Q, &D, &E ) ) != 0 )
+    if( ( ret = mbedtls_rsa_import( &rsa, &N, &P, &Q, &D, &E ) ) != 0 )
     {
         mbedtls_printf( " failed\n  ! mbedtls_rsa_import returned %d\n\n",
-                        return_val );
+                        ret );
         goto exit;
     }
 
-    if( ( return_val = mbedtls_rsa_complete( &rsa ) ) != 0 )
+    if( ( ret = mbedtls_rsa_complete( &rsa ) ) != 0 )
     {
         mbedtls_printf( " failed\n  ! mbedtls_rsa_complete returned %d\n\n",
-                        return_val );
+                        ret );
         goto exit;
     }
 
@@ -154,7 +152,6 @@
      */
     if( ( f = fopen( "result-enc.txt", "rb" ) ) == NULL )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( "\n  ! Could not open %s\n\n", "result-enc.txt" );
         goto exit;
     }
@@ -169,7 +166,6 @@
 
     if( i != rsa.len )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( "\n  ! Invalid RSA signature format\n\n" );
         goto exit;
     }
@@ -180,14 +176,13 @@
     mbedtls_printf( "\n  . Decrypting the encrypted data" );
     fflush( stdout );
 
-    return_val = mbedtls_rsa_pkcs1_decrypt( &rsa, mbedtls_ctr_drbg_random,
+    ret = mbedtls_rsa_pkcs1_decrypt( &rsa, mbedtls_ctr_drbg_random,
                                             &ctr_drbg, MBEDTLS_RSA_PRIVATE, &i,
                                             buf, result, 1024 );
-    if( return_val != 0 )
+    if( ret != 0 )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( " failed\n  ! mbedtls_rsa_pkcs1_decrypt returned %d\n\n",
-                        return_val );
+                        ret );
         goto exit;
     }
 
@@ -195,6 +190,8 @@
 
     mbedtls_printf( "The decrypted result is: '%s'\n\n", result );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     mbedtls_ctr_drbg_free( &ctr_drbg );
     mbedtls_entropy_free( &entropy );
@@ -208,6 +205,6 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( exit_val );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_FS_IO */
diff --git a/programs/pkey/rsa_encrypt.c b/programs/pkey/rsa_encrypt.c
index 81c27d8..411657a 100644
--- a/programs/pkey/rsa_encrypt.c
+++ b/programs/pkey/rsa_encrypt.c
@@ -30,12 +30,12 @@
 #else
 #include <stdio.h>
 #include <stdlib.h>
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#define mbedtls_exit       exit
-#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
-#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
-#endif
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define mbedtls_exit            exit
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_RSA_C) && \
     defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_FS_IO) && \
@@ -61,7 +61,8 @@
 int main( int argc, char *argv[] )
 {
     FILE *f;
-    int return_val, exit_val;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     size_t i;
     mbedtls_rsa_context rsa;
     mbedtls_entropy_context entropy;
@@ -71,8 +72,6 @@
     const char *pers = "rsa_encrypt";
     mbedtls_mpi N, E;
 
-    exit_val = MBEDTLS_EXIT_SUCCESS;
-
     if( argc != 2 )
     {
         mbedtls_printf( "usage: rsa_encrypt <string of max 100 characters>\n" );
@@ -81,7 +80,7 @@
         mbedtls_printf( "\n" );
 #endif
 
-        mbedtls_exit( MBEDTLS_EXIT_FAILURE );
+        mbedtls_exit( exit_code );
     }
 
     mbedtls_printf( "\n  . Seeding the random number generator..." );
@@ -92,14 +91,13 @@
     mbedtls_ctr_drbg_init( &ctr_drbg );
     mbedtls_entropy_init( &entropy );
 
-    return_val = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func,
-                                        &entropy, (const unsigned char *) pers,
-                                        strlen( pers ) );
-    if( return_val != 0 )
+    ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func,
+                                 &entropy, (const unsigned char *) pers,
+                                 strlen( pers ) );
+    if( ret != 0 )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( " failed\n  ! mbedtls_ctr_drbg_seed returned %d\n",
-                        return_val );
+                        ret );
         goto exit;
     }
 
@@ -108,35 +106,30 @@
 
     if( ( f = fopen( "rsa_pub.txt", "rb" ) ) == NULL )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( " failed\n  ! Could not open rsa_pub.txt\n" \
                 "  ! Please run rsa_genkey first\n\n" );
         goto exit;
     }
 
-    if( ( return_val = mbedtls_mpi_read_file( &N, 16, f ) ) != 0 ||
-        ( return_val = mbedtls_mpi_read_file( &E, 16, f ) ) != 0 )
+    if( ( ret = mbedtls_mpi_read_file( &N, 16, f ) ) != 0 ||
+        ( ret = mbedtls_mpi_read_file( &E, 16, f ) ) != 0 )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( " failed\n  ! mbedtls_mpi_read_file returned %d\n\n",
-                        return_val );
+                        ret );
         fclose( f );
         goto exit;
     }
     fclose( f );
 
-    if( ( return_val = mbedtls_rsa_import( &rsa, &N, NULL,
-                                           NULL, NULL, &E ) ) != 0 )
+    if( ( ret = mbedtls_rsa_import( &rsa, &N, NULL, NULL, NULL, &E ) ) != 0 )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( " failed\n  ! mbedtls_rsa_import returned %d\n\n",
-                        return_val );
+                        ret );
         goto exit;
     }
 
     if( strlen( argv[1] ) > 100 )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( " Input data larger than 100 characters.\n\n" );
         goto exit;
     }
@@ -149,14 +142,13 @@
     mbedtls_printf( "\n  . Generating the RSA encrypted value" );
     fflush( stdout );
 
-    return_val = mbedtls_rsa_pkcs1_encrypt( &rsa, mbedtls_ctr_drbg_random,
-                                            &ctr_drbg, MBEDTLS_RSA_PUBLIC,
-                                            strlen( argv[1] ), input, buf );
-    if( return_val != 0 )
+    ret = mbedtls_rsa_pkcs1_encrypt( &rsa, mbedtls_ctr_drbg_random,
+                                     &ctr_drbg, MBEDTLS_RSA_PUBLIC,
+                                     strlen( argv[1] ), input, buf );
+    if( ret != 0 )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( " failed\n  ! mbedtls_rsa_pkcs1_encrypt returned %d\n\n",
-                        return_val );
+                        ret );
         goto exit;
     }
 
@@ -165,7 +157,6 @@
      */
     if( ( f = fopen( "result-enc.txt", "wb+" ) ) == NULL )
     {
-        exit_val = MBEDTLS_EXIT_FAILURE;
         mbedtls_printf( " failed\n  ! Could not create %s\n\n", "result-enc.txt" );
         goto exit;
     }
@@ -178,6 +169,8 @@
 
     mbedtls_printf( "\n  . Done (created \"%s\")\n\n", "result-enc.txt" );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     mbedtls_mpi_free( &N ); mbedtls_mpi_free( &E );
     mbedtls_ctr_drbg_free( &ctr_drbg );
@@ -189,7 +182,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( exit_val );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_ENTROPY_C &&
           MBEDTLS_FS_IO && MBEDTLS_CTR_DRBG_C */
diff --git a/programs/pkey/rsa_genkey.c b/programs/pkey/rsa_genkey.c
index 9399217..3359e14 100644
--- a/programs/pkey/rsa_genkey.c
+++ b/programs/pkey/rsa_genkey.c
@@ -29,8 +29,11 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_ENTROPY_C) && \
     defined(MBEDTLS_RSA_C) && defined(MBEDTLS_GENPRIME) && \
@@ -61,7 +64,8 @@
 #else
 int main( void )
 {
-    int ret;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_rsa_context rsa;
     mbedtls_entropy_context entropy;
     mbedtls_ctr_drbg_context ctr_drbg;
@@ -105,14 +109,12 @@
         ( ret = mbedtls_rsa_export_crt( &rsa, &DP, &DQ, &QP ) )      != 0 )
     {
         mbedtls_printf( " failed\n  ! could not export RSA parameters\n\n" );
-        ret = 1;
         goto exit;
     }
 
     if( ( fpub = fopen( "rsa_pub.txt", "wb+" ) ) == NULL )
     {
         mbedtls_printf( " failed\n  ! could not open rsa_pub.txt for writing\n\n" );
-        ret = 1;
         goto exit;
     }
 
@@ -129,7 +131,6 @@
     if( ( fpriv = fopen( "rsa_priv.txt", "wb+" ) ) == NULL )
     {
         mbedtls_printf( " failed\n  ! could not open rsa_priv.txt for writing\n" );
-        ret = 1;
         goto exit;
     }
 
@@ -160,6 +161,8 @@
 */
     mbedtls_printf( " ok\n\n" );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
     if( fpub  != NULL )
@@ -180,7 +183,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_RSA_C &&
           MBEDTLS_GENPRIME && MBEDTLS_FS_IO && MBEDTLS_CTR_DRBG_C */
diff --git a/programs/pkey/rsa_sign.c b/programs/pkey/rsa_sign.c
index 89018cb..b16fe5d 100644
--- a/programs/pkey/rsa_sign.c
+++ b/programs/pkey/rsa_sign.c
@@ -29,10 +29,13 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#define mbedtls_snprintf   snprintf
-#endif
+#include <stdlib.h>
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define mbedtls_snprintf        snprintf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) ||  \
     !defined(MBEDTLS_SHA256_C) || !defined(MBEDTLS_MD_C) || \
@@ -55,7 +58,8 @@
 int main( int argc, char *argv[] )
 {
     FILE *f;
-    int ret;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     size_t i;
     mbedtls_rsa_context rsa;
     unsigned char hash[32];
@@ -69,8 +73,6 @@
     mbedtls_mpi_init( &D ); mbedtls_mpi_init( &E ); mbedtls_mpi_init( &DP );
     mbedtls_mpi_init( &DQ ); mbedtls_mpi_init( &QP );
 
-    ret = 1;
-
     if( argc != 2 )
     {
         mbedtls_printf( "usage: rsa_sign <filename>\n" );
@@ -87,7 +89,6 @@
 
     if( ( f = fopen( "rsa_priv.txt", "rb" ) ) == NULL )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Could not open rsa_priv.txt\n" \
                 "  ! Please run rsa_genkey first\n\n" );
         goto exit;
@@ -159,7 +160,6 @@
 
     if( ( f = fopen( filename, "wb+" ) ) == NULL )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Could not create %s\n\n", argv[1] );
         goto exit;
     }
@@ -172,6 +172,8 @@
 
     mbedtls_printf( "\n  . Done (created \"%s\")\n\n", filename );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
     mbedtls_rsa_free( &rsa );
@@ -184,7 +186,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_SHA256_C &&
           MBEDTLS_FS_IO */
diff --git a/programs/pkey/rsa_sign_pss.c b/programs/pkey/rsa_sign_pss.c
index 7b6f14d..b0b0f7e 100644
--- a/programs/pkey/rsa_sign_pss.c
+++ b/programs/pkey/rsa_sign_pss.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_snprintf   snprintf
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_snprintf        snprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_MD_C) || !defined(MBEDTLS_ENTROPY_C) ||  \
     !defined(MBEDTLS_RSA_C) || !defined(MBEDTLS_SHA256_C) ||        \
@@ -61,6 +64,7 @@
 {
     FILE *f;
     int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_pk_context pk;
     mbedtls_entropy_context entropy;
     mbedtls_ctr_drbg_context ctr_drbg;
@@ -101,7 +105,6 @@
 
     if( ( ret = mbedtls_pk_parse_keyfile( &pk, argv[1], "" ) ) != 0 )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Could not read key from '%s'\n", argv[1] );
         mbedtls_printf( "  ! mbedtls_pk_parse_public_keyfile returned %d\n\n", ret );
         goto exit;
@@ -109,7 +112,6 @@
 
     if( !mbedtls_pk_can_do( &pk, MBEDTLS_PK_RSA ) )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Key is not an RSA key\n" );
         goto exit;
     }
@@ -145,7 +147,6 @@
 
     if( ( f = fopen( filename, "wb+" ) ) == NULL )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Could not create %s\n\n", filename );
         goto exit;
     }
@@ -161,6 +162,8 @@
 
     mbedtls_printf( "\n  . Done (created \"%s\")\n\n", filename );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     mbedtls_pk_free( &pk );
     mbedtls_ctr_drbg_free( &ctr_drbg );
@@ -171,7 +174,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_RSA_C &&
           MBEDTLS_SHA256_C && MBEDTLS_PK_PARSE_C && MBEDTLS_FS_IO &&
diff --git a/programs/pkey/rsa_verify.c b/programs/pkey/rsa_verify.c
index 1f827aa..6f88345 100644
--- a/programs/pkey/rsa_verify.c
+++ b/programs/pkey/rsa_verify.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#define mbedtls_snprintf   snprintf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define mbedtls_snprintf        snprintf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) ||  \
     !defined(MBEDTLS_SHA256_C) || !defined(MBEDTLS_MD_C) || \
@@ -54,7 +57,8 @@
 int main( int argc, char *argv[] )
 {
     FILE *f;
-    int ret, c;
+    int ret = 1, c;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     size_t i;
     mbedtls_rsa_context rsa;
     unsigned char hash[32];
@@ -62,7 +66,6 @@
     char filename[512];
 
     mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, 0 );
-    ret = 1;
 
     if( argc != 2 )
     {
@@ -100,7 +103,6 @@
     /*
      * Extract the RSA signature from the text file
      */
-    ret = 1;
     mbedtls_snprintf( filename, sizeof(filename), "%s.sig", argv[1] );
 
     if( ( f = fopen( filename, "rb" ) ) == NULL )
@@ -146,7 +148,7 @@
 
     mbedtls_printf( "\n  . OK (the signature is valid)\n\n" );
 
-    ret = 0;
+    exit_code = MBEDTLS_EXIT_SUCCESS;
 
 exit:
 
@@ -157,7 +159,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_SHA256_C &&
           MBEDTLS_FS_IO */
diff --git a/programs/pkey/rsa_verify_pss.c b/programs/pkey/rsa_verify_pss.c
index 31b720f..7c9c68f 100644
--- a/programs/pkey/rsa_verify_pss.c
+++ b/programs/pkey/rsa_verify_pss.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_snprintf   snprintf
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_snprintf        snprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_MD_C) || !defined(MBEDTLS_ENTROPY_C) ||  \
     !defined(MBEDTLS_RSA_C) || !defined(MBEDTLS_SHA256_C) ||        \
@@ -60,6 +63,7 @@
 {
     FILE *f;
     int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     size_t i;
     mbedtls_pk_context pk;
     unsigned char hash[32];
@@ -91,7 +95,6 @@
 
     if( !mbedtls_pk_can_do( &pk, MBEDTLS_PK_RSA ) )
     {
-        ret = 1;
         mbedtls_printf( " failed\n  ! Key is not an RSA key\n" );
         goto exit;
     }
@@ -101,7 +104,6 @@
     /*
      * Extract the RSA signature from the file
      */
-    ret = 1;
     mbedtls_snprintf( filename, 512, "%s.sig", argv[2] );
 
     if( ( f = fopen( filename, "rb" ) ) == NULL )
@@ -139,7 +141,7 @@
 
     mbedtls_printf( "\n  . OK (the signature is valid)\n\n" );
 
-    ret = 0;
+    exit_code = MBEDTLS_EXIT_SUCCESS;
 
 exit:
     mbedtls_pk_free( &pk );
@@ -149,7 +151,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_SHA256_C &&
           MBEDTLS_PK_PARSE_C && MBEDTLS_FS_IO */
diff --git a/programs/random/gen_entropy.c b/programs/random/gen_entropy.c
index 792d381..a1eb386 100644
--- a/programs/random/gen_entropy.c
+++ b/programs/random/gen_entropy.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_FS_IO)
 #include "mbedtls/entropy.h"
@@ -49,20 +52,21 @@
 int main( int argc, char *argv[] )
 {
     FILE *f;
-    int i, k, ret;
+    int i, k, ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_entropy_context entropy;
     unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
 
     if( argc < 2 )
     {
         mbedtls_fprintf( stderr, "usage: %s <output filename>\n", argv[0] );
-        return( 1 );
+        return( exit_code );
     }
 
     if( ( f = fopen( argv[1], "wb+" ) ) == NULL )
     {
         mbedtls_printf( "failed to open '%s' for writing.\n", argv[1] );
-        return( 1 );
+        return( exit_code );
     }
 
     mbedtls_entropy_init( &entropy );
@@ -72,7 +76,8 @@
         ret = mbedtls_entropy_func( &entropy, buf, sizeof( buf ) );
         if( ret != 0 )
         {
-            mbedtls_printf("failed!\n");
+            mbedtls_printf( "  failed\n  !  mbedtls_entropy_func returned -%04X\n",
+                            ret );
             goto cleanup;
         }
 
@@ -83,7 +88,7 @@
         fflush( stdout );
     }
 
-    ret = 0;
+    exit_code = MBEDTLS_EXIT_SUCCESS;
 
 cleanup:
     mbedtls_printf( "\n" );
@@ -91,6 +96,6 @@
     fclose( f );
     mbedtls_entropy_free( &entropy );
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_ENTROPY_C */
diff --git a/programs/random/gen_random_ctr_drbg.c b/programs/random/gen_random_ctr_drbg.c
index c76f99d..5ade946 100644
--- a/programs/random/gen_random_ctr_drbg.c
+++ b/programs/random/gen_random_ctr_drbg.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_CTR_DRBG_C) && defined(MBEDTLS_ENTROPY_C) && \
  defined(MBEDTLS_FS_IO)
@@ -52,7 +55,8 @@
 int main( int argc, char *argv[] )
 {
     FILE *f;
-    int i, k, ret;
+    int i, k, ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_ctr_drbg_context ctr_drbg;
     mbedtls_entropy_context entropy;
     unsigned char buf[1024];
@@ -62,13 +66,13 @@
     if( argc < 2 )
     {
         mbedtls_fprintf( stderr, "usage: %s <output filename>\n", argv[0] );
-        return( 1 );
+        return( exit_code );
     }
 
     if( ( f = fopen( argv[1], "wb+" ) ) == NULL )
     {
         mbedtls_printf( "failed to open '%s' for writing.\n", argv[1] );
-        return( 1 );
+        return( exit_code );
     }
 
     mbedtls_entropy_init( &entropy );
@@ -116,7 +120,7 @@
         fflush( stdout );
     }
 
-    ret = 0;
+    exit_code = MBEDTLS_EXIT_SUCCESS;
 
 cleanup:
     mbedtls_printf("\n");
@@ -125,6 +129,6 @@
     mbedtls_ctr_drbg_free( &ctr_drbg );
     mbedtls_entropy_free( &entropy );
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_CTR_DRBG_C && MBEDTLS_ENTROPY_C */
diff --git a/programs/random/gen_random_havege.c b/programs/random/gen_random_havege.c
index 6c31462..3fb3f01 100644
--- a/programs/random/gen_random_havege.c
+++ b/programs/random/gen_random_havege.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_HAVEGE_C) && defined(MBEDTLS_FS_IO)
 #include "mbedtls/havege.h"
@@ -51,20 +54,21 @@
 {
     FILE *f;
     time_t t;
-    int i, k, ret = 0;
+    int i, k, ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_havege_state hs;
     unsigned char buf[1024];
 
     if( argc < 2 )
     {
         mbedtls_fprintf( stderr, "usage: %s <output filename>\n", argv[0] );
-        return( 1 );
+        return( exit_code );
     }
 
     if( ( f = fopen( argv[1], "wb+" ) ) == NULL )
     {
         mbedtls_printf( "failed to open '%s' for writing.\n", argv[1] );
-        return( 1 );
+        return( exit_code );
     }
 
     mbedtls_havege_init( &hs );
@@ -73,11 +77,10 @@
 
     for( i = 0, k = 768; i < k; i++ )
     {
-        if( mbedtls_havege_random( &hs, buf, sizeof( buf ) ) != 0 )
+        if( ( ret = mbedtls_havege_random( &hs, buf, sizeof( buf ) ) ) != 0 )
         {
-            mbedtls_printf( "Failed to get random from source.\n" );
-
-            ret = 1;
+            mbedtls_printf( " failed\n  !  mbedtls_havege_random returned -0x%04X",
+                            -ret );
             goto exit;
         }
 
@@ -93,9 +96,11 @@
 
     mbedtls_printf(" \n ");
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     mbedtls_havege_free( &hs );
     fclose( f );
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_HAVEGE_C */
diff --git a/programs/ssl/ssl_client1.c b/programs/ssl/ssl_client1.c
index 01cee13..bf7c013 100644
--- a/programs/ssl/ssl_client1.c
+++ b/programs/ssl/ssl_client1.c
@@ -30,11 +30,13 @@
 #else
 #include <stdio.h>
 #include <stdlib.h>
-#define mbedtls_time       time
-#define mbedtls_time_t     time_t
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#endif
+#define mbedtls_time            time
+#define mbedtls_time_t          time_t
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) ||  \
     !defined(MBEDTLS_SSL_TLS_C) || !defined(MBEDTLS_SSL_CLI_C) || \
@@ -80,7 +82,8 @@
 
 int main( void )
 {
-    int ret, len;
+    int ret = 1, len;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_net_context server_fd;
     uint32_t flags;
     unsigned char buf[1024];
@@ -281,10 +284,12 @@
 
     mbedtls_ssl_close_notify( &ssl );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
 #ifdef MBEDTLS_ERROR_C
-    if( ret != 0 )
+    if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
         char error_buf[100];
         mbedtls_strerror( ret, error_buf, 100 );
@@ -305,7 +310,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_SSL_TLS_C &&
           MBEDTLS_SSL_CLI_C && MBEDTLS_NET_C && MBEDTLS_RSA_C &&
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index 8e2feb1..8151432 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -246,7 +246,11 @@
     "    server_port=%%d      default: 4433\n"              \
     "    request_page=%%s     default: \".\"\n"             \
     "    request_size=%%d     default: about 34 (basic request)\n"           \
-    "                        (minimum: 0, max: " MAX_REQUEST_SIZE_STR " )\n" \
+    "                        (minimum: 0, max: " MAX_REQUEST_SIZE_STR ")\n"  \
+    "                        If 0, in the first exchange only an empty\n"    \
+    "                        application data message is sent followed by\n" \
+    "                        a second non-empty message before attempting\n" \
+    "                        to read a response from the server\n"           \
     "    debug_level=%%d      default: 0 (disabled)\n"      \
     "    nbio=%%d             default: 0 (blocking I/O)\n"  \
     "                        options: 1 (non-blocking), 2 (added delays)\n" \
@@ -1528,10 +1532,13 @@
 
     if( opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM )
     {
-        for( written = 0, frags = 0; written < len; written += ret, frags++ )
+        written = 0;
+        frags = 0;
+
+        do
         {
-            while( ( ret = mbedtls_ssl_write( &ssl, buf + written, len - written ) )
-                           <= 0 )
+            while( ( ret = mbedtls_ssl_write( &ssl, buf + written,
+                                              len - written ) ) < 0 )
             {
                 if( ret != MBEDTLS_ERR_SSL_WANT_READ &&
                     ret != MBEDTLS_ERR_SSL_WANT_WRITE )
@@ -1540,7 +1547,11 @@
                     goto exit;
                 }
             }
+
+            frags++;
+            written += ret;
         }
+        while( written < len );
     }
     else /* Not stream, so datagram */
     {
@@ -1567,6 +1578,13 @@
     buf[written] = '\0';
     mbedtls_printf( " %d bytes written in %d fragments\n\n%s\n", written, frags, (char *) buf );
 
+    /* Send a non-empty request if request_size == 0 */
+    if ( len == 0 )
+    {
+        opt.request_size = DFL_REQUEST_SIZE;
+        goto send_request;
+    }
+
     /*
      * 7. Read the HTTP response
      */
diff --git a/programs/ssl/ssl_fork_server.c b/programs/ssl/ssl_fork_server.c
index 7624896..1c3a806 100644
--- a/programs/ssl/ssl_fork_server.c
+++ b/programs/ssl/ssl_fork_server.c
@@ -29,10 +29,13 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#define mbedtls_time_t     time_t
-#endif
+#include <stdlib.h>
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define mbedtls_time_t          time_t
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_CERTS_C) ||    \
     !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_SSL_TLS_C) || \
@@ -95,7 +98,8 @@
 
 int main( void )
 {
-    int ret, len, cnt = 0, pid;
+    int ret = 1, len, cnt = 0, pid;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_net_context listen_fd, client_fd;
     unsigned char buf[1024];
     const char *pers = "ssl_fork_server";
@@ -392,6 +396,8 @@
         goto exit;
     }
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     mbedtls_net_free( &client_fd );
     mbedtls_net_free( &listen_fd );
@@ -408,7 +414,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_CERTS_C && MBEDTLS_ENTROPY_C &&
           MBEDTLS_SSL_TLS_C && MBEDTLS_SSL_SRV_C && MBEDTLS_NET_C &&
diff --git a/programs/ssl/ssl_mail_client.c b/programs/ssl/ssl_mail_client.c
index 04b847a..04f8910 100644
--- a/programs/ssl/ssl_mail_client.c
+++ b/programs/ssl/ssl_mail_client.c
@@ -30,11 +30,13 @@
 #else
 #include <stdio.h>
 #include <stdlib.h>
-#define mbedtls_time       time
-#define mbedtls_time_t     time_t
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#endif
+#define mbedtls_time            time
+#define mbedtls_time_t          time_t
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) ||  \
     !defined(MBEDTLS_SSL_TLS_C) || !defined(MBEDTLS_SSL_CLI_C) || \
@@ -346,7 +348,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret = 0, len;
+    int ret = 1, len;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_net_context server_fd;
     unsigned char buf[1024];
 #if defined(MBEDTLS_BASE64_C)
@@ -499,8 +502,8 @@
                               mbedtls_test_cas_pem_len );
 #else
     {
-        ret = 1;
         mbedtls_printf("MBEDTLS_CERTS_C and/or MBEDTLS_PEM_PARSE_C not defined.");
+        goto exit;
     }
 #endif
     if( ret < 0 )
@@ -529,8 +532,8 @@
                               mbedtls_test_cli_crt_len );
 #else
     {
-        ret = -1;
         mbedtls_printf("MBEDTLS_CERTS_C not defined.");
+        goto exit;
     }
 #endif
     if( ret != 0 )
@@ -549,8 +552,8 @@
                 mbedtls_test_cli_key_len, NULL, 0 );
 #else
     {
-        ret = -1;
         mbedtls_printf("MBEDTLS_CERTS_C or MBEDTLS_PEM_PARSE_C not defined.");
+        goto exit;
     }
 #endif
     if( ret != 0 )
@@ -819,6 +822,8 @@
 
     mbedtls_ssl_close_notify( &ssl );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
     mbedtls_net_free( &server_fd );
@@ -835,7 +840,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_SSL_TLS_C &&
           MBEDTLS_SSL_CLI_C && MBEDTLS_NET_C && MBEDTLS_RSA_C **
diff --git a/programs/test/ssl_cert_test.c b/programs/test/ssl_cert_test.c
index 9cfcd2d..fd3526f 100644
--- a/programs/test/ssl_cert_test.c
+++ b/programs/test/ssl_cert_test.c
@@ -29,9 +29,12 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_snprintf   snprintf
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_snprintf        snprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_RSA_C) && defined(MBEDTLS_X509_CRT_PARSE_C) && \
     defined(MBEDTLS_FS_IO) && defined(MBEDTLS_X509_CRL_PARSE_C)
@@ -80,7 +83,8 @@
 
 int main( void )
 {
-    int ret, i;
+    int ret = 1, i;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_x509_crt cacert;
     mbedtls_x509_crl crl;
     char buf[10240];
@@ -210,7 +214,6 @@
         if( ! mbedtls_pk_can_do( &clicert.pk, MBEDTLS_PK_RSA ) )
         {
             mbedtls_printf( " failed\n  !  certificate's key is not RSA\n\n" );
-            ret = MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE;
             goto exit;
         }
 
@@ -241,6 +244,8 @@
         mbedtls_pk_free( &pk );
     }
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     mbedtls_x509_crt_free( &cacert );
     mbedtls_x509_crl_free( &crl );
@@ -250,7 +255,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_RSA_C && MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_FS_IO &&
           MBEDTLS_X509_CRL_PARSE_C */
diff --git a/programs/test/udp_proxy.c b/programs/test/udp_proxy.c
index 20624d2..1865b0f 100644
--- a/programs/test/udp_proxy.c
+++ b/programs/test/udp_proxy.c
@@ -37,10 +37,12 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
-#define mbedtls_time       time
-#define mbedtls_time_t     time_t
-#define mbedtls_printf     printf
-#endif
+#define mbedtls_time            time
+#define mbedtls_time_t          time_t
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_NET_C)
 int main( void )
@@ -468,7 +470,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
 
     mbedtls_net_context listen_fd, client_fd, server_fd;
 
@@ -591,10 +594,12 @@
         }
     }
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
 #ifdef MBEDTLS_ERROR_C
-    if( ret != 0 )
+    if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
         char error_buf[100];
         mbedtls_strerror( ret, error_buf, 100 );
@@ -612,7 +617,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret != 0 );
+    return( exit_code );
 }
 
 #endif /* MBEDTLS_NET_C */
diff --git a/programs/util/pem2der.c b/programs/util/pem2der.c
index ad2c6ac..73a9fb5 100644
--- a/programs/util/pem2der.c
+++ b/programs/util/pem2der.c
@@ -29,10 +29,13 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_free       free
-#define mbedtls_calloc    calloc
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_free            free
+#define mbedtls_calloc          calloc
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if defined(MBEDTLS_BASE64_C) && defined(MBEDTLS_FS_IO)
 #include "mbedtls/error.h"
@@ -178,7 +181,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret = 0;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     unsigned char *pem_buffer = NULL;
     unsigned char der_buffer[4096];
     char buf[1024];
@@ -273,6 +277,8 @@
 
     mbedtls_printf( " ok\n" );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     free( pem_buffer );
 
@@ -281,6 +287,6 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BASE64_C && MBEDTLS_FS_IO */
diff --git a/programs/x509/cert_app.c b/programs/x509/cert_app.c
index c893ca8..c57ecca 100644
--- a/programs/x509/cert_app.c
+++ b/programs/x509/cert_app.c
@@ -30,11 +30,13 @@
 #else
 #include <stdio.h>
 #include <stdlib.h>
-#define mbedtls_time       time
-#define mbedtls_time_t     time_t
-#define mbedtls_fprintf    fprintf
-#define mbedtls_printf     printf
-#endif
+#define mbedtls_time            time
+#define mbedtls_time_t          time_t
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) ||  \
     !defined(MBEDTLS_SSL_TLS_C) || !defined(MBEDTLS_SSL_CLI_C) || \
@@ -145,7 +147,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret = 0;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_net_context server_fd;
     unsigned char buf[1024];
     mbedtls_entropy_context entropy;
@@ -180,7 +183,6 @@
     {
     usage:
         mbedtls_printf( USAGE );
-        ret = 2;
         goto exit;
     }
 
@@ -252,19 +254,23 @@
 
     if( strlen( opt.ca_path ) )
     {
-        ret = mbedtls_x509_crt_parse_path( &cacert, opt.ca_path );
+        if( ( ret = mbedtls_x509_crt_parse_path( &cacert, opt.ca_path ) ) < 0 )
+        {
+            mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse_path returned -0x%x\n\n", -ret );
+            goto exit;
+        }
+
         verify = 1;
     }
     else if( strlen( opt.ca_file ) )
     {
-        ret = mbedtls_x509_crt_parse_file( &cacert, opt.ca_file );
-        verify = 1;
-    }
+        if( ( ret = mbedtls_x509_crt_parse_file( &cacert, opt.ca_file ) ) < 0 )
+        {
+            mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse_file returned -0x%x\n\n", -ret );
+            goto exit;
+        }
 
-    if( ret < 0 )
-    {
-        mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse returned -0x%x\n\n", -ret );
-        goto exit;
+        verify = 1;
     }
 
     mbedtls_printf( " ok (%d skipped)\n", ret );
@@ -332,8 +338,6 @@
             cur = cur->next;
         }
 
-        ret = 0;
-
         /*
          * 1.3 Verify the certificate
          */
@@ -470,6 +474,8 @@
     else
         goto usage;
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
     mbedtls_net_free( &server_fd );
@@ -485,10 +491,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    if( ret < 0 )
-        ret = 1;
-
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_SSL_TLS_C &&
           MBEDTLS_SSL_CLI_C && MBEDTLS_NET_C && MBEDTLS_RSA_C &&
diff --git a/programs/x509/cert_req.c b/programs/x509/cert_req.c
index 30df216..a32ac50 100644
--- a/programs/x509/cert_req.c
+++ b/programs/x509/cert_req.c
@@ -29,8 +29,11 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_X509_CSR_WRITE_C) || !defined(MBEDTLS_FS_IO) ||  \
     !defined(MBEDTLS_PK_PARSE_C) || !defined(MBEDTLS_SHA256_C) || \
@@ -133,7 +136,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret = 0;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_pk_context key;
     char buf[1024];
     int i;
@@ -156,7 +160,6 @@
     {
     usage:
         mbedtls_printf( USAGE );
-        ret = 1;
         goto exit;
     }
 
@@ -317,9 +320,11 @@
 
     mbedtls_printf( " ok\n" );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
-    if( ret != 0 && ret != 1)
+    if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
 #ifdef MBEDTLS_ERROR_C
         mbedtls_strerror( ret, buf, sizeof( buf ) );
@@ -339,7 +344,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_X509_CSR_WRITE_C && MBEDTLS_PK_PARSE_C && MBEDTLS_FS_IO &&
           MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C && MBEDTLS_PEM_WRITE_C */
diff --git a/programs/x509/cert_write.c b/programs/x509/cert_write.c
index 9cc582d..26ab88a 100644
--- a/programs/x509/cert_write.c
+++ b/programs/x509/cert_write.c
@@ -29,8 +29,11 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_X509_CRT_WRITE_C) || \
     !defined(MBEDTLS_X509_CRT_PARSE_C) || !defined(MBEDTLS_FS_IO) || \
@@ -211,7 +214,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret = 0;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_x509_crt issuer_crt;
     mbedtls_pk_context loaded_issuer_key, loaded_subject_key;
     mbedtls_pk_context *issuer_key = &loaded_issuer_key,
@@ -248,7 +252,6 @@
     {
     usage:
         mbedtls_printf( USAGE );
-        ret = 1;
         goto exit;
     }
 
@@ -615,7 +618,6 @@
         {
             mbedtls_printf( " failed\n  !  issuer_key does not match "
                             "issuer certificate\n\n" );
-            ret = -1;
             goto exit;
         }
     }
@@ -788,6 +790,8 @@
 
     mbedtls_printf( " ok\n" );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     mbedtls_x509write_crt_free( &crt );
     mbedtls_pk_free( &loaded_subject_key );
@@ -801,7 +805,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_X509_CRT_WRITE_C && MBEDTLS_X509_CRT_PARSE_C &&
           MBEDTLS_FS_IO && MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C &&
diff --git a/programs/x509/crl_app.c b/programs/x509/crl_app.c
index 210d19e..f831683 100644
--- a/programs/x509/crl_app.c
+++ b/programs/x509/crl_app.c
@@ -29,8 +29,11 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) ||  \
     !defined(MBEDTLS_X509_CRL_PARSE_C) || !defined(MBEDTLS_FS_IO)
@@ -67,7 +70,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret = 0;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     unsigned char buf[100000];
     mbedtls_x509_crl crl;
     int i;
@@ -131,6 +135,8 @@
 
     mbedtls_printf( "%s\n", buf );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     mbedtls_x509_crl_free( &crl );
 
@@ -139,7 +145,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_X509_CRL_PARSE_C &&
           MBEDTLS_FS_IO */
diff --git a/programs/x509/req_app.c b/programs/x509/req_app.c
index 8410a53..0f20c85 100644
--- a/programs/x509/req_app.c
+++ b/programs/x509/req_app.c
@@ -29,8 +29,11 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
-#define mbedtls_printf     printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf          printf
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) ||  \
     !defined(MBEDTLS_X509_CSR_PARSE_C) || !defined(MBEDTLS_FS_IO)
@@ -67,7 +70,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret = 0;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
     unsigned char buf[100000];
     mbedtls_x509_csr csr;
     int i;
@@ -131,6 +135,8 @@
 
     mbedtls_printf( "%s\n", buf );
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
     mbedtls_x509_csr_free( &csr );
 
@@ -139,7 +145,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( exit_code );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_X509_CSR_PARSE_C &&
           MBEDTLS_FS_IO */
diff --git a/scripts/config.pl b/scripts/config.pl
index 5bf2785..468aeb9 100755
--- a/scripts/config.pl
+++ b/scripts/config.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # This file is part of mbed TLS (https://tls.mbed.org)
 #
diff --git a/scripts/generate_errors.pl b/scripts/generate_errors.pl
index ac0fbff..4f0ad31 100755
--- a/scripts/generate_errors.pl
+++ b/scripts/generate_errors.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Generate error.c
 #
diff --git a/scripts/generate_features.pl b/scripts/generate_features.pl
index 2aa695c..1bd82ca 100755
--- a/scripts/generate_features.pl
+++ b/scripts/generate_features.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 
 use strict;
diff --git a/scripts/generate_visualc_files.pl b/scripts/generate_visualc_files.pl
index e042a44..811c71f 100755
--- a/scripts/generate_visualc_files.pl
+++ b/scripts/generate_visualc_files.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Generate main file, individual apps and solution files for MS Visual Studio
 # 2010
diff --git a/scripts/massif_max.pl b/scripts/massif_max.pl
index d1ce4ca..4e3342a 100755
--- a/scripts/massif_max.pl
+++ b/scripts/massif_max.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Parse a massif.out.xxx file and output peak total memory usage
 
diff --git a/scripts/rename.pl b/scripts/rename.pl
index c29519e..fb42809 100755
--- a/scripts/rename.pl
+++ b/scripts/rename.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # This file is part of mbed TLS (https://tls.mbed.org)
 #
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 4c7e906..797831e 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -336,6 +336,7 @@
             echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
             echo "${start_red}FAILED: $failure_count${end_color}$failure_summary"
             echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
+            exit 1
         elif [ -z "${1-}" ]; then
             echo "SUCCESS :)"
         fi
@@ -532,6 +533,24 @@
 msg "test: compat.sh RC4, DES & NULL (full config)" # ~ 2 min
 if_build_succeeded env OPENSSL_CMD="$OPENSSL_LEGACY" GNUTLS_CLI="$GNUTLS_LEGACY_CLI" GNUTLS_SERV="$GNUTLS_LEGACY_SERV" tests/compat.sh -e '3DES\|DES-CBC3' -f 'NULL\|DES\|RC4\|ARCFOUR'
 
+msg "build: make, full config + DEPRECATED_WARNING, gcc -O" # ~ 30s
+cleanup
+cp "$CONFIG_H" "$CONFIG_BAK"
+scripts/config.pl full
+scripts/config.pl set MBEDTLS_DEPRECATED_WARNING
+# Build with -O -Wextra to catch a maximum of issues.
+make CC=gcc CFLAGS='-O -Werror -Wall -Wextra' lib programs
+make CC=gcc CFLAGS='-O -Werror -Wall -Wextra -Wno-unused-function' tests
+
+msg "build: make, full config + DEPRECATED_REMOVED, clang -O" # ~ 30s
+# No cleanup, just tweak the configuration and rebuild
+make clean
+scripts/config.pl unset MBEDTLS_DEPRECATED_WARNING
+scripts/config.pl set MBEDTLS_DEPRECATED_REMOVED
+# Build with -O -Wextra to catch a maximum of issues.
+make CC=clang CFLAGS='-O -Werror -Wall -Wextra' lib programs
+make CC=clang CFLAGS='-O -Werror -Wall -Wextra -Wno-unused-function' tests
+
 msg "test/build: curves.pl (gcc)" # ~ 4 min
 cleanup
 record_status tests/scripts/curves.pl
@@ -640,15 +659,30 @@
 fi
 
 if uname -a | grep -F x86_64 >/dev/null; then
-    msg "build: i386, make, gcc" # ~ 30s
+    # Build once with -O0, to compile out the i386 specific inline assembly
+    msg "build: i386, make, gcc -O0 (ASan build)" # ~ 30s
     cleanup
-    make CC=gcc CFLAGS='-Werror -Wall -Wextra -m32'
+    cp "$CONFIG_H" "$CONFIG_BAK"
+    scripts/config.pl full
+    make CC=gcc CFLAGS='-O0 -Werror -Wall -Wextra -m32 -fsanitize=address'
 
-    msg "test: i386, make, gcc"
+    msg "test: i386, make, gcc -O0 (ASan build)"
+    make test
+
+    # Build again with -O1, to compile in the i386 specific inline assembly
+    msg "build: i386, make, gcc -O1 (ASan build)" # ~ 30s
+    cleanup
+    cp "$CONFIG_H" "$CONFIG_BAK"
+    scripts/config.pl full
+    make CC=gcc CFLAGS='-O1 -Werror -Wall -Wextra -m32 -fsanitize=address'
+
+    msg "test: i386, make, gcc -O1 (ASan build)"
     make test
 
     msg "build: 64-bit ILP32, make, gcc" # ~ 30s
     cleanup
+    cp "$CONFIG_H" "$CONFIG_BAK"
+    scripts/config.pl full
     make CC=gcc CFLAGS='-Werror -Wall -Wextra -mx32'
 
     msg "test: 64-bit ILP32, make, gcc"
diff --git a/tests/scripts/check-doxy-blocks.pl b/tests/scripts/check-doxy-blocks.pl
index b0fd696..4967699 100755
--- a/tests/scripts/check-doxy-blocks.pl
+++ b/tests/scripts/check-doxy-blocks.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Detect comment blocks that are likely meant to be doxygen blocks but aren't.
 #
diff --git a/tests/scripts/curves.pl b/tests/scripts/curves.pl
index 0041814..ddc90c5 100755
--- a/tests/scripts/curves.pl
+++ b/tests/scripts/curves.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # curves.pl
 #
diff --git a/tests/scripts/depends-hashes.pl b/tests/scripts/depends-hashes.pl
index 29dcfb0..f57e7ed 100755
--- a/tests/scripts/depends-hashes.pl
+++ b/tests/scripts/depends-hashes.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # depends-hashes.pl
 #
diff --git a/tests/scripts/depends-pkalgs.pl b/tests/scripts/depends-pkalgs.pl
index 14c92b2..97a43e8 100755
--- a/tests/scripts/depends-pkalgs.pl
+++ b/tests/scripts/depends-pkalgs.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # depends-pkalgs.pl
 #
diff --git a/tests/scripts/gen_ctr_drbg.pl b/tests/scripts/gen_ctr_drbg.pl
index ee13024..3c074be 100755
--- a/tests/scripts/gen_ctr_drbg.pl
+++ b/tests/scripts/gen_ctr_drbg.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # Based on NIST CTR_DRBG.rsp validation file
 # Only uses AES-256-CTR cases that use a Derivation function
diff --git a/tests/scripts/gen_gcm_decrypt.pl b/tests/scripts/gen_gcm_decrypt.pl
index 6decac2..03809cb 100755
--- a/tests/scripts/gen_gcm_decrypt.pl
+++ b/tests/scripts/gen_gcm_decrypt.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # Based on NIST gcmDecryptxxx.rsp validation files
 # Only first 3 of every set used for compile time saving
diff --git a/tests/scripts/gen_gcm_encrypt.pl b/tests/scripts/gen_gcm_encrypt.pl
index 8adbbce..29ec677 100755
--- a/tests/scripts/gen_gcm_encrypt.pl
+++ b/tests/scripts/gen_gcm_encrypt.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # Based on NIST gcmEncryptIntIVxxx.rsp validation files
 # Only first 3 of every set used for compile time saving
diff --git a/tests/scripts/gen_pkcs1_v21_sign_verify.pl b/tests/scripts/gen_pkcs1_v21_sign_verify.pl
index 678e2f9..110cb4b 100755
--- a/tests/scripts/gen_pkcs1_v21_sign_verify.pl
+++ b/tests/scripts/gen_pkcs1_v21_sign_verify.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 
 use strict;
diff --git a/tests/scripts/key-exchanges.pl b/tests/scripts/key-exchanges.pl
index d167c67..3bf7ae3 100755
--- a/tests/scripts/key-exchanges.pl
+++ b/tests/scripts/key-exchanges.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # key-exchanges.pl
 #
diff --git a/tests/scripts/list-enum-consts.pl b/tests/scripts/list-enum-consts.pl
index 633e3fd..21c25b3 100755
--- a/tests/scripts/list-enum-consts.pl
+++ b/tests/scripts/list-enum-consts.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 use warnings;
 use strict;
diff --git a/tests/scripts/recursion.pl b/tests/scripts/recursion.pl
index 3ad42b1..431e592 100755
--- a/tests/scripts/recursion.pl
+++ b/tests/scripts/recursion.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Find functions making recursive calls to themselves.
 # (Multiple recursion where a() calls b() which calls a() not covered.)
diff --git a/tests/scripts/run-test-suites.pl b/tests/scripts/run-test-suites.pl
index 7e2974b..6279358 100755
--- a/tests/scripts/run-test-suites.pl
+++ b/tests/scripts/run-test-suites.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # run-test-suites.pl
 #
diff --git a/tests/scripts/test-ref-configs.pl b/tests/scripts/test-ref-configs.pl
index 600fc75..e1d2184 100755
--- a/tests/scripts/test-ref-configs.pl
+++ b/tests/scripts/test-ref-configs.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # test-ref-configs.pl
 #
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 2f8ea4f..a70ace3 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -308,7 +308,7 @@
         done
     }
 else
-    echo "Warning: lsof not available, wait_server_start = sleep $START_DELAY"
+    echo "Warning: lsof not available, wait_server_start = sleep"
     wait_server_start() {
         sleep "$START_DELAY"
     }
@@ -1151,6 +1151,38 @@
             -s "received FALLBACK_SCSV" \
             -S "inapropriate fallback"
 
+# Test sending and receiving empty application data records
+
+run_test    "Encrypt then MAC: empty application data record" \
+            "$P_SRV auth_mode=none debug_level=4 etm=1" \
+            "$P_CLI auth_mode=none etm=1 request_size=0 force_ciphersuite=TLS-ECDHE-RSA-WITH-AES-256-CBC-SHA" \
+            0 \
+            -S "0000:  0f 0f 0f 0f 0f 0f 0f 0f 0f 0f 0f 0f 0f 0f 0f 0f" \
+            -s "dumping 'input payload after decrypt' (0 bytes)" \
+            -c "0 bytes written in 1 fragments"
+
+run_test    "Default, no Encrypt then MAC: empty application data record" \
+            "$P_SRV auth_mode=none debug_level=4 etm=0" \
+            "$P_CLI auth_mode=none etm=0 request_size=0" \
+            0 \
+            -s "dumping 'input payload after decrypt' (0 bytes)" \
+            -c "0 bytes written in 1 fragments"
+
+run_test    "Encrypt then MAC, DTLS: empty application data record" \
+            "$P_SRV auth_mode=none debug_level=4 etm=1 dtls=1" \
+            "$P_CLI auth_mode=none etm=1 request_size=0 force_ciphersuite=TLS-ECDHE-RSA-WITH-AES-256-CBC-SHA dtls=1" \
+            0 \
+            -S "0000:  0f 0f 0f 0f 0f 0f 0f 0f 0f 0f 0f 0f 0f 0f 0f 0f" \
+            -s "dumping 'input payload after decrypt' (0 bytes)" \
+            -c "0 bytes written in 1 fragments"
+
+run_test    "Default, no Encrypt then MAC, DTLS: empty application data record" \
+            "$P_SRV auth_mode=none debug_level=4 etm=0 dtls=1" \
+            "$P_CLI auth_mode=none etm=0 request_size=0 dtls=1" \
+            0 \
+            -s "dumping 'input payload after decrypt' (0 bytes)" \
+            -c "0 bytes written in 1 fragments"
+
 ## ClientHello generated with
 ## "openssl s_client -CAfile tests/data_files/test-ca.crt -tls1_1 -connect localhost:4433 -cipher ..."
 ## then manually twiddling the ciphersuite list.
diff --git a/tests/suites/test_suite_dhm.data b/tests/suites/test_suite_dhm.data
index e351ebd..734fd97 100644
--- a/tests/suites/test_suite_dhm.data
+++ b/tests/suites/test_suite_dhm.data
@@ -19,10 +19,10 @@
 Diffie-Hellman zero modulus
 dhm_do_dhm:10:"0":10:"5":MBEDTLS_ERR_DHM_BAD_INPUT_DATA
 
-Diffie-Hallman load parameters from file
+Diffie-Hellman load parameters from file
 dhm_file:"data_files/dhparams.pem":"9e35f430443a09904f3a39a979797d070df53378e79c2438bef4e761f3c714553328589b041c809be1d6c6b5f1fc9f47d3a25443188253a992a56818b37ba9de5a40d362e56eff0be5417474c125c199272c8fe41dea733df6f662c92ae76556e755d10c64e6a50968f67fc6ea73d0dca8569be2ba204e23580d8bca2f4975b3":"02":128
 
-Diffie-Hallman load parameters from file
+Diffie-Hellman load parameters from file
 dhm_file:"data_files/dh.optlen.pem":"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":"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":256
 
 Diffie-Hellman selftest