Some minor improvements to read_msg_fd() made it safe to use both

set_msg_fd_in() and read_msg_fd() during the early phase of being
a client sender (up through the sending of the file list).  This
makes sure that the sender monitors the socket from the receiver
for any messages that it might send to us, and thus avoids a hang
when verbosity is high.

diff --git a/io.c b/io.c
index 50eca53..5d5b030 100644 (file)
--- a/io.c
+++ b/io.c
@@ -46,6 +46,7 @@ extern int io_timeout;
 extern int am_server;
 extern int am_daemon;
 extern int am_sender;
+extern int am_generator;
 extern int eol_nulls;
 extern int checksum_seed;
 extern int protocol_version;
@@ -162,17 +163,17 @@ void io_set_sock_fds(int f_in, int f_out)
        sock_f_out = f_out;
 }
 
-/** Setup the fd used to receive MSG_* messages.  Only needed when
- * we're the generator because the sender and receiver both use the
- * multiplexed I/O setup. */
+/* Setup the fd used to receive MSG_* messages.  Only needed 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). */
 void set_msg_fd_in(int fd)
 {
        msg_fd_in = fd;
 }
 
-/** Setup the fd used to send our MSG_* messages.  Only needed when
- * we're the receiver because the generator and the sender both use
- * the multiplexed I/O setup. */
+/* Setup the fd used to send our MSG_* messages.  Only needed when
+ * we're the receiver (to send our messages to the generator). */
 void set_msg_fd_out(int fd)
 {
        msg_fd_out = fd;
@@ -205,8 +206,10 @@ void send_msg(enum msgcode code, char *buf, int len)
        msg_list_push(NORMAL_FLUSH);
 }
 
-/** Read a message from the MSG_* fd and dispatch it.  This is only
- * called by the generator. */
+/* 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];
@@ -226,14 +229,14 @@ static void read_msg_fd(void)
 
        switch (tag) {
        case MSG_DONE:
-               if (len != 0) {
+               if (len != 0 || !am_generator) {
                        rprintf(FERROR, "invalid message %d:%d\n", tag, len);
                        exit_cleanup(RERR_STREAMIO);
                }
                redo_list_add(-1);
                break;
        case MSG_REDO:
-               if (len != 4) {
+               if (len != 4 || !am_generator) {
                        rprintf(FERROR, "invalid message %d:%d\n", tag, len);
                        exit_cleanup(RERR_STREAMIO);
                }