diff -aur rsync-3.0.0pre8.orig/rsync.1 rsync-3.0.0pre8/rsync.1
--- rsync-3.0.0pre8.orig/rsync.1	2008-01-21 19:34:20.000000000 -0600
+++ rsync-3.0.0pre8/rsync.1	2008-01-21 22:20:56.000000000 -0600
@@ -263,6 +263,37 @@
 WARNING: On some systems environment variables are visible to all
 users. On those systems using \fB\-\-password\-file\fP is recommended.
 .PP 
+You may also specify a file descriptor number to use for the communications
+channel to the daemon.  This is done by specifying a hostname of '&<integer>'.
+When doing this rsync does NOT make a TCP connection but rather uses the file
+descriptor number specified by the given integer and assumes this is an already
+connected socket (or other bi-directional handle) to the daemon.  Values of
+1 and 2 may not be specified as these are used for rsync's logging.  This
+feature is useful when some other application is going to make a connection on 
+behalf of rsync (possibly pre-communicating with the other end) and then execute
+rsync letting it inherit the connected socket handle.  
+
+Be sure that when rsync is executed that stdout and stderr are not also
+referencing the same connection (as some programs using this model may do) since
+rsync will be logging to stdout and/or stderr.
+
+Be sure to properly quote the '&' character on the command shell since it would
+otherwise be interpreted to use everything preceding it as a command to be
+executed in the background.
+
+For example:
+.PP
+.nf
+	#!/bin/sh
+	# make sure stdout also goes to stderr in case it was also opened to stdin
+	rsync \-va '&0'::module/src/ /dest/ 1>&2
+.fi
+
+.PP
+The script above inherits file descriptor 0 as an already connected socket handle
+and runs rsync using that socket as the connection to the daemon
+  
+.PP 
 You may establish the connection via a web proxy by setting the
 environment variable RSYNC_PROXY to a hostname:port pair pointing to
 your web proxy.  Note that your web proxy's configuration must support
diff -aur rsync-3.0.0pre8.orig/socket.c rsync-3.0.0pre8/socket.c
--- rsync-3.0.0pre8.orig/socket.c	2008-01-21 19:34:20.000000000 -0600
+++ rsync-3.0.0pre8/socket.c	2008-01-21 21:39:25.000000000 -0600
@@ -30,6 +30,9 @@
 #include <netinet/ip.h>
 #include <netinet/tcp.h>
 
+#include <sys/stat.h>
+#include <unistd.h>
+
 extern char *bind_address;
 extern int default_af_hint;
 extern int connect_timeout;
@@ -309,7 +312,9 @@
 /**
  * Open an outgoing socket, but allow for it to be intercepted by
  * $RSYNC_CONNECT_PROG, which will execute a program across a TCP
- * socketpair rather than really opening a socket.
+ * socketpair rather than really opening a socket.  Also, allow a
+ * special hostname of "&<integer>" to specify a file descriptor 
+ * number as an already connected socket to the daemon.
  *
  * We use this primarily in testing to detect TCP flow bugs, but not
  * cause security problems by really opening remote connections.
@@ -366,6 +371,33 @@
 	}
 	if (prog)
 		return sock_exec(prog);
+
+	/*
+	 * special "&<integer>" hostname means to use the specified integer as 
+	 * the file descriptor of an already connected socket handle to the 
+	 * daemon. (Though it be a handle to something other than an actual
+	 * socket)
+	 */
+	if(host[0] == '&') {
+		int fd = atoi(host+1);
+		struct stat buf;
+		
+		if(fd == 1 || fd == 2) {
+			rsyserr(FERROR, errno, "%s specified the stdout or stderr which are used for logging", host);
+			return -1;
+		}
+		
+		/* test that fd is a valid file descriptor */
+		if(fstat(fd,&buf)!=0) {
+			rsyserr(FERROR, errno, "%s specified an invalid file descriptor", host);
+			return -1;
+		}
+
+		/* don't know of a way to check whether fd is open for read AND write */
+
+		return fd;
+	}
+
 	return open_socket_out(host, port, bind_addr, af_hint);
 }