Undefine OpenSSL::SSL for no socket platforms

This fixes a linkage error about `ossl_ssl_type` on platforms which do
not have socket, like WASI.

Even before this patch, some items are disabled under `OPENSSL_NO_SOCK` since
ruby/ruby@ee22fad
However, due to some new use of OpenSSL::SSL::Socket over the past few years,
the build under `OPENSSL_NO_SOCK` had been broken.

This patch guards whole `OpenSSL::SSL` items by `OPENSSL_NO_SOCK`.

[ky: adjusted to apply on top of my previous commit that removed the
OpenSSL::ExtConfig, and added a guard to lib/openssl/ssl.rb.]

Author: kateinoigakukun

ext/openssl/ossl_ssl.c

@@ -11,6 +11,7 @@
  */
 #include "ossl.h"
 
+#ifndef OPENSSL_NO_SOCK
 #define numberof(ary) (int)(sizeof(ary)/sizeof((ary)[0]))
 
 #if !defined(TLS1_3_VERSION) && \
@@ -1537,7 +1538,6 @@ ossl_sslctx_flush_sessions(int argc, VALUE *argv, VALUE self)
 /*
  * SSLSocket class
  */
-#ifndef OPENSSL_NO_SOCK
 static inline int
 ssl_started(SSL *ssl)
 {
@@ -2565,6 +2565,7 @@ Init_ossl_ssl(void)
     rb_mWaitWritable = rb_define_module_under(rb_cIO, "WaitWritable");
 #endif
 
+#ifndef OPENSSL_NO_SOCK
     id_call = rb_intern_const("call");
     ID_callback_state = rb_intern_const("callback_state");
 
@@ -2939,9 +2940,6 @@ Init_ossl_ssl(void)
      * Document-class: OpenSSL::SSL::SSLSocket
      */
     cSSLSocket = rb_define_class_under(mSSL, "SSLSocket", rb_cObject);
-#ifdef OPENSSL_NO_SOCK
-    rb_define_method(cSSLSocket, "initialize", rb_f_notimplement, -1);
-#else
     rb_define_alloc_func(cSSLSocket, ossl_ssl_s_alloc);
     rb_define_method(cSSLSocket, "initialize", ossl_ssl_initialize, -1);
     rb_undef_method(cSSLSocket, "initialize_copy");
@@ -2976,7 +2974,6 @@ Init_ossl_ssl(void)
 # ifndef OPENSSL_NO_NEXTPROTONEG
     rb_define_method(cSSLSocket, "npn_protocol", ossl_ssl_npn_protocol, 0);
 # endif
-#endif
 
     rb_define_const(mSSL, "VERIFY_NONE", INT2NUM(SSL_VERIFY_NONE));
     rb_define_const(mSSL, "VERIFY_PEER", INT2NUM(SSL_VERIFY_PEER));
@@ -3138,4 +3135,5 @@ Init_ossl_ssl(void)
     DefIVarID(io);
     DefIVarID(context);
     DefIVarID(hostname);
+#endif /* !defined(OPENSSL_NO_SOCK) */
 }

ext/openssl/ossl_ssl_session.c

@@ -4,6 +4,7 @@
 
 #include "ossl.h"
 
+#ifndef OPENSSL_NO_SOCK
 VALUE cSSLSession;
 static VALUE eSSLSession;
 
@@ -299,6 +300,7 @@ static VALUE ossl_ssl_session_to_text(VALUE self)
 	return ossl_membio2str(out);
 }
 
+#endif /* !defined(OPENSSL_NO_SOCK) */
 
 void Init_ossl_ssl_session(void)
 {
@@ -307,6 +309,7 @@ void Init_ossl_ssl_session(void)
     mSSL = rb_define_module_under(mOSSL, "SSL");
     eOSSLError = rb_define_class_under(mOSSL, "OpenSSLError", rb_eStandardError);
 #endif
+#ifndef OPENSSL_NO_SOCK
 	cSSLSession = rb_define_class_under(mSSL, "Session", rb_cObject);
 	eSSLSession = rb_define_class_under(cSSLSession, "SessionError", eOSSLError);
 
@@ -324,4 +327,5 @@ void Init_ossl_ssl_session(void)
 	rb_define_method(cSSLSession, "to_der", ossl_ssl_session_to_der, 0);
 	rb_define_method(cSSLSession, "to_pem", ossl_ssl_session_to_pem, 0);
 	rb_define_method(cSSLSession, "to_text", ossl_ssl_session_to_text, 0);
+#endif /* !defined(OPENSSL_NO_SOCK) */
 }

lib/openssl/ssl.rb

@@ -11,6 +11,9 @@
 =end
 
 require "openssl/buffering"
+
+if defined?(OpenSSL::SSL)
+
 require "io/nonblock"
 require "ipaddr"
 require "socket"
@@ -540,3 +543,5 @@ def close
     end
   end
 end
+
+end