OpenSSL::SSL::SSLSocket#ssl_write

static VALUE
ossl_ssl_write(VALUE self, VALUE str)
{
    SSL *ssl;
    VALUE cb_state;

    GetSSL(self, ssl);
    if (!ssl_started(ssl))
        rb_raise(eSSLError, "SSL session is not started yet");

    StringValue(str);
    /* SSL_write(3ssl) manpage states num == 0 is undefined */
    int num = RSTRING_LENINT(str);
    if (num == 0)
        return INT2FIX(0);

#ifdef __APPLE__
  retry:;
#endif
    int frozen = RB_OBJ_FROZEN(str);
    if (!frozen) {
        rb_str_locktmp(str);
    }
    int nwritten = SSL_write(ssl, RSTRING_PTR(str), num);
    if (!frozen) {
        rb_str_unlocktmp(str);
    }
    int saved_errno = errno_mapped();

    cb_state = rb_attr_get(self, ID_callback_state);
    if (!NIL_P(cb_state)) {
        rb_ivar_set(self, ID_callback_state, Qnil);
        ossl_clear_error();
        rb_jump_tag(NUM2INT(cb_state));
    }

    switch (SSL_get_error(ssl, nwritten)) {
      case SSL_ERROR_NONE:
        return INT2NUM(nwritten);
      case SSL_ERROR_WANT_WRITE:
        return sym_wait_writable;
      case SSL_ERROR_WANT_READ:
        return sym_wait_readable;
      case SSL_ERROR_SYSCALL:
        if (saved_errno) {
            ossl_clear_error();
#ifdef __APPLE__
            /*
             * It appears that send syscall can return EPROTOTYPE if the
             * socket is being torn down. Retry to get a proper errno to
             * make the error handling in line with the socket library.
             * [Bug #14713] https://bugs.ruby-lang.org/issues/14713
             */
            if (saved_errno == EPROTOTYPE)
                goto retry;
#endif
            rb_exc_raise(rb_syserr_new(saved_errno, "SSL_write"));
        }
        /* fallthrough */
      default:
        ossl_raise(eSSLError, "SSL_write");
    }
}