Test ssl_pthread_server

Test ssl_pthread_server with both TLS 1.2 and TLS 1.3.
Test against both OpenSSL and GnuTLS.

In the server, flush more often. Otherwise, when stdout is redirected to a
file, the server gets killed before it writes important information, such as
the logs that we expect in the test cases.

Clean up compile-time requirements in ssl_pthread_server.c: any certificate-based
key exchange is ok, so don't insist on built-in RSA.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/programs/ssl/ssl_pthread_server.c b/programs/ssl/ssl_pthread_server.c
index fcb8f2f..7edf4a8 100644
--- a/programs/ssl/ssl_pthread_server.c
+++ b/programs/ssl/ssl_pthread_server.c
@@ -10,20 +10,21 @@
 
 #include "mbedtls/platform.h"
 
-#if !defined(MBEDTLS_BIGNUM_C)  || !defined(MBEDTLS_ENTROPY_C) ||         \
-    !defined(MBEDTLS_SSL_TLS_C) || !defined(MBEDTLS_SSL_SRV_C) ||         \
-    !defined(MBEDTLS_NET_C) || !defined(MBEDTLS_RSA_C) ||                 \
-    !defined(MBEDTLS_CTR_DRBG_C) || !defined(MBEDTLS_X509_CRT_PARSE_C) || \
-    !defined(MBEDTLS_FS_IO) || !defined(MBEDTLS_THREADING_C) ||           \
-    !defined(MBEDTLS_THREADING_PTHREAD) || !defined(MBEDTLS_PEM_PARSE_C)
+#if !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C) ||      \
+    !defined(MBEDTLS_NET_C) || !defined(MBEDTLS_SSL_SRV_C) ||           \
+    !defined(MBEDTLS_PEM_PARSE_C) || !defined(MBEDTLS_X509_CRT_PARSE_C)
 int main(void)
 {
-    mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_ENTROPY_C "
-                   "and/or MBEDTLS_SSL_TLS_C and/or MBEDTLS_SSL_SRV_C and/or "
-                   "MBEDTLS_NET_C and/or MBEDTLS_RSA_C and/or "
-                   "MBEDTLS_CTR_DRBG_C and/or MBEDTLS_X509_CRT_PARSE_C and/or "
-                   "MBEDTLS_THREADING_C and/or MBEDTLS_THREADING_PTHREAD "
-                   "and/or MBEDTLS_PEM_PARSE_C not defined.\n");
+    mbedtls_printf("MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C and/or "
+                   "MBEDTLS_NET_C and/or MBEDTLS_SSL_SRV_C and/or "
+                   "MBEDTLS_PEM_PARSE_C and/or MBEDTLS_X509_CRT_PARSE_C "
+                   "not defined.\n");
+    mbedtls_exit(0);
+}
+#elif !defined(MBEDTLS_THREADING_C) || !defined(MBEDTLS_THREADING_PTHREAD)
+int main(void)
+{
+    mbedtls_printf("MBEDTLS_THREADING_PTHREAD not defined.\n");
     mbedtls_exit(0);
 }
 #else
@@ -123,6 +124,7 @@
      * 5. Handshake
      */
     mbedtls_printf("  [ #%ld ]  Performing the SSL/TLS handshake\n", thread_id);
+    fflush(stdout);
 
     while ((ret = mbedtls_ssl_handshake(&ssl)) != 0) {
         if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
@@ -138,6 +140,7 @@
      * 6. Read the HTTP Request
      */
     mbedtls_printf("  [ #%ld ]  < Read from client\n", thread_id);
+    fflush(stdout);
 
     do {
         len = sizeof(buf) - 1;
@@ -170,6 +173,7 @@
         len = ret;
         mbedtls_printf("  [ #%ld ]  %d bytes read\n=====\n%s\n=====\n",
                        thread_id, len, (char *) buf);
+        fflush(stdout);
 
         if (ret > 0) {
             break;
@@ -180,6 +184,7 @@
      * 7. Write the 200 Response
      */
     mbedtls_printf("  [ #%ld ]  > Write to client:\n", thread_id);
+    fflush(stdout);
 
     len = sprintf((char *) buf, HTTP_RESPONSE,
                   mbedtls_ssl_get_ciphersuite(&ssl));
@@ -201,6 +206,7 @@
     len = ret;
     mbedtls_printf("  [ #%ld ]  %d bytes written\n=====\n%s\n=====\n",
                    thread_id, len, (char *) buf);
+    fflush(stdout);
 
     mbedtls_printf("  [ #%ld ]  . Closing the connection...", thread_id);
 
@@ -214,6 +220,7 @@
     }
 
     mbedtls_printf(" ok\n");
+    fflush(stdout);
 
     ret = 0;
 
@@ -442,6 +449,7 @@
      * 3. Wait until a client connects
      */
     mbedtls_printf("  [ main ]  Waiting for a remote connection\n");
+    fflush(stdout);
 
     if ((ret = mbedtls_net_accept(&listen_fd, &client_fd,
                                   NULL, 0, NULL)) != 0) {
@@ -483,7 +491,4 @@
     mbedtls_exit(ret);
 }
 
-#endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C &&
-          MBEDTLS_SSL_TLS_C && MBEDTLS_SSL_SRV_C && MBEDTLS_NET_C &&
-          MBEDTLS_RSA_C && MBEDTLS_CTR_DRBG_C && MBEDTLS_THREADING_C &&
-          MBEDTLS_THREADING_PTHREAD && MBEDTLS_PEM_PARSE_C */
+#endif /* configuration allows running this program */