extmod/modussl_axtls: Allow to close ssl stream multiple times.

Make sure that 2nd close has no effect and operations on closed streams
are handled properly.

Author: pfalcon

extmod/modussl_axtls.c

@@ -102,6 +102,11 @@ STATIC void socket_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kin
 STATIC mp_uint_t socket_read(mp_obj_t o_in, void *buf, mp_uint_t size, int *errcode) {
     mp_obj_ssl_socket_t *o = MP_OBJ_TO_PTR(o_in);
 
+    if (o->ssl_sock == NULL) {
+        *errcode = EBADF;
+        return MP_STREAM_ERROR;
+    }
+
     while (o->bytes_left == 0) {
         mp_int_t r = ssl_read(o->ssl_sock, &o->buf);
         if (r == SSL_OK) {
@@ -131,6 +136,12 @@ STATIC mp_uint_t socket_read(mp_obj_t o_in, void *buf, mp_uint_t size, int *errc
 
 STATIC mp_uint_t socket_write(mp_obj_t o_in, const void *buf, mp_uint_t size, int *errcode) {
     mp_obj_ssl_socket_t *o = MP_OBJ_TO_PTR(o_in);
+
+    if (o->ssl_sock == NULL) {
+        *errcode = EBADF;
+        return MP_STREAM_ERROR;
+    }
+
     mp_int_t r = ssl_write(o->ssl_sock, buf, size);
     if (r < 0) {
         *errcode = r;
@@ -151,9 +162,14 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_2(socket_setblocking_obj, socket_setblocking);
 
 STATIC mp_obj_t socket_close(mp_obj_t self_in) {
     mp_obj_ssl_socket_t *self = MP_OBJ_TO_PTR(self_in);
-    ssl_free(self->ssl_sock);
-    ssl_ctx_free(self->ssl_ctx);
-    return mp_stream_close(self->sock);
+    if (self->ssl_sock != NULL) {
+        ssl_free(self->ssl_sock);
+        ssl_ctx_free(self->ssl_ctx);
+        self->ssl_sock = NULL;
+        return mp_stream_close(self->sock);
+    }
+
+    return mp_const_none;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(socket_close_obj, socket_close);
 

tests/extmod/ussl_basic.py

@@ -43,6 +43,14 @@
 
 # close
 ss.close()
+# close 2nd time
+ss.close()
+
+# read on closed socket
+try:
+    ss.read(10)
+except OSError as er:
+    print('read:', repr(er))
 
 # write on closed socket
 try:

tests/extmod/ussl_basic.py.exp

@@ -5,4 +5,5 @@ setblocking: NotImplementedError
 4
 b''
 read: OSError(-261,)
-write: OSError(-256,)
+read: OSError(9,)
+write: OSError(9,)