From 98f8c9a5e54d90043248f8c64228e15a2baeec30 Mon Sep 17 00:00:00 2001
From: Wayne Davison <wayned@samba.org>
Date: Sat, 20 Nov 2004 07:07:37 +0000
Subject: [PATCH] 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.

---
 io.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/io.c b/io.c
index 50eca536..5d5b030c 100644
--- 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);
 		}
-- 
2.34.1