+ msg_fd_out = fd;
+ set_nonblocking(msg_fd_out);
+}
+
+/* Add a message to the pending MSG_* list. */
+static void msg_list_add(struct msg_list *lst, int code, const char *buf, int len, int convert)
+{
+ struct msg_list_item *m;
+ int sz = len + 4 + sizeof m[0] - 1;
+
+ if (!(m = (struct msg_list_item *)new_array(char, sz)))
+ out_of_memory("msg_list_add");
+ m->next = NULL;
+ m->convert = convert;
+ SIVAL(m->buf, 0, ((code+MPLEX_BASE)<<24) | len);
+ memcpy(m->buf + 4, buf, len);
+ if (lst->tail)
+ lst->tail->next = m;
+ else
+ lst->head = m;
+ lst->tail = m;
+}
+
+static inline int flush_a_msg(int fd)
+{
+ struct msg_list_item *m = msg_queue.head;
+ int len = IVAL(m->buf, 0) & 0xFFFFFF;
+ int tag = *((uchar*)m->buf+3) - MPLEX_BASE;
+
+ if (!(msg_queue.head = m->next))
+ msg_queue.tail = NULL;
+
+ defer_forwarding_messages++;
+ mplex_write(fd, tag, m->buf + 4, len, m->convert);
+ defer_forwarding_messages--;
+
+ free(m);
+
+ return len;
+}
+
+static void msg_flush(void)
+{
+ if (am_generator) {
+ while (msg_queue.head && io_multiplexing_out)
+ stats.total_written += flush_a_msg(sock_f_out) + 4;
+ } else {
+ while (msg_queue.head)
+ (void)flush_a_msg(msg_fd_out);
+ }
+}
+
+static void check_for_d_option_error(const char *msg)
+{
+ static char rsync263_opts[] = "BCDHIKLPRSTWabceghlnopqrtuvxz";
+ char *colon;
+ int saw_d = 0;
+
+ if (*msg != 'r'
+ || strncmp(msg, REMOTE_OPTION_ERROR, sizeof REMOTE_OPTION_ERROR - 1) != 0)
+ return;
+
+ msg += sizeof REMOTE_OPTION_ERROR - 1;
+ if (*msg == '-' || (colon = strchr(msg, ':')) == NULL
+ || strncmp(colon, REMOTE_OPTION_ERROR2, sizeof REMOTE_OPTION_ERROR2 - 1) != 0)
+ return;
+
+ for ( ; *msg != ':'; msg++) {
+ if (*msg == 'd')
+ saw_d = 1;
+ else if (*msg == 'e')
+ break;
+ else if (strchr(rsync263_opts, *msg) == NULL)
+ return;
+ }
+
+ if (saw_d) {
+ rprintf(FWARNING,
+ "*** Try using \"--old-d\" if remote rsync is <= 2.6.3 ***\n");
+ }
+}
+
+/* Read a message from the MSG_* fd and handle it. This is called either
+ * during the early stages of being a local sender (up through the sending
+ * of the file list) or when we're the generator (to fetch the messages
+ * from the receiver). */
+static void read_msg_fd(void)
+{
+ char buf[2048];
+ size_t n;
+ struct file_list *flist;
+ int fd = msg_fd_in;
+ int tag, len;
+
+ /* Temporarily disable msg_fd_in. This is needed to avoid looping back
+ * to this routine from writefd_unbuffered(). */
+ no_flush++;
+ msg_fd_in = -1;
+ defer_forwarding_messages++;
+
+ readfd(fd, buf, 4);
+ tag = IVAL(buf, 0);
+
+ len = tag & 0xFFFFFF;
+ tag = (tag >> 24) - MPLEX_BASE;
+
+ switch (tag) {
+ case MSG_DONE:
+ if (len < 0 || len > 1 || !am_generator) {
+ invalid_msg:
+ rprintf(FERROR, "invalid message %d:%d [%s%s]\n",
+ tag, len, who_am_i(),
+ inc_recurse ? "/inc" : "");
+ exit_cleanup(RERR_STREAMIO);