Index: ext/openssl/ossl_ssl.c
===================================================================
--- ext/openssl/ossl_ssl.c	(revision 20459)
+++ ext/openssl/ossl_ssl.c	(working copy)
@@ -12,6 +12,14 @@
  */
 #include "ossl.h"
 
+#define rb_sys_fail_path(path) rb_sys_fail(NIL_P(path) ? 0 : RSTRING_PTR(path))
+
+#if defined(HAVE_FCNTL_H) || defined(_WIN32)
+#include <fcntl.h>
+#elif defined(HAVE_SYS_FCNTL_H)
+#include <sys/fcntl.h>
+#endif
+
 #if defined(HAVE_UNISTD_H)
 #  include <unistd.h> /* for read(), and write() */
 #endif
@@ -1034,7 +1042,11 @@
                 rb_io_wait_writable(FPTR_TO_FD(fptr));
                 continue;
 	    case SSL_ERROR_WANT_READ:
-                rb_io_wait_readable(FPTR_TO_FD(fptr));
+                if (fcntl(fptr->fd, F_GETFL, O_NONBLOCK) == 1) {
+                    rb_sys_fail_path(fptr->pathv);
+                } else {
+                    rb_io_wait_readable(FPTR_TO_FD(fptr));
+                }
 		continue;
 	    case SSL_ERROR_SYSCALL:
 		if(ERR_peek_error() == 0 && nread == 0) rb_eof_error();
@@ -1059,6 +1071,27 @@
 
 /*
  * call-seq:
+ *    ssl.read_nonblock(length) => string
+ *    ssl.read_nonblock(length, buffer) => buffer
+ *
+ * === Parameters
+ * * +length+ is a positive integer.
+ * * +buffer+ is a string used to store the result.
+ */
+static VALUE
+ossl_ssl_read_nonblock(int argc, VALUE *argv, VALUE self)
+{
+    SSL *ssl;
+    rb_io_t *fptr;
+
+    Data_Get_Struct(self, SSL, ssl);
+    GetOpenFile(ossl_ssl_get_io(self), fptr);
+    rb_io_set_nonblock(fptr);
+    return ossl_ssl_read(argc, argv, self);
+}
+
+/*
+ * call-seq:
  *    ssl.syswrite(string) => integer
  */
 static VALUE
@@ -1421,6 +1454,7 @@
     rb_define_method(cSSLSocket, "sysread",    ossl_ssl_read, -1);
     rb_define_method(cSSLSocket, "syswrite",   ossl_ssl_write, 1);
     rb_define_method(cSSLSocket, "sysclose",   ossl_ssl_close, 0);
+    rb_define_method(cSSLSocket, "read_nonblock",    ossl_ssl_read_nonblock, -1);
     rb_define_method(cSSLSocket, "cert",       ossl_ssl_get_cert, 0);
     rb_define_method(cSSLSocket, "peer_cert",  ossl_ssl_get_peer_cert, 0);
     rb_define_method(cSSLSocket, "peer_cert_chain", ossl_ssl_get_peer_cert_chain, 0);