Prevent the "Connection reset by peer" messages often seen from Cygwin.

Result of a lot of discussion over the last year and a half.  Based on
a patch from Randy O'Meara, cleaned up a bit by Max Bowsher.

4 files changed, 41 insertions, 1 deletions

diff --git a/NEWS b/NEWS
index 578860be..47433c67 100644
--- a/NEWS
+++ b/NEWS
@@ -73,6 +73,8 @@ rsync changes since last release
     * Fixed a bug that prevented rsync from creating intervening directories
       when --relative-paths/-R is set.  (Craig Barratt)
 
+    * Prevent "Connection reset by peer" messages from Cygwin. (Randy O'Meara)
+
   INTERNAL:
 
     * Many code cleanups and improved internal documentation.  (Martin 
diff --git a/cleanup.c b/cleanup.c
index 8543217d..2a850832 100644
--- a/cleanup.c
+++ b/cleanup.c
@@ -22,6 +22,32 @@
 #include "rsync.h"
 
 /**
+ * Close all open sockets and files, allowing a (somewhat) graceful
+ * shutdown() of socket connections.  This eliminates the abortive
+ * TCP RST sent by a Winsock-based system when the close() occurs.
+ **/
+void close_all()
+{
+#ifdef SHUTDOWN_ALL_SOCKETS
+	int max_fd;
+	int fd;
+	int ret;
+	struct stat st;
+
+	max_fd = sysconf(_SC_OPEN_MAX) - 1;
+	for (fd = max_fd; fd >= 0; fd--) {
+		ret = fstat(fd,&st);
+		if (fstat(fd,&st) == 0) {
+			if (is_a_socket(fd)) {
+				ret = shutdown(fd, 2);
+			}
+			ret = close(fd);
+		}
+	}
+#endif
+}
+
+/**
  * @file cleanup.c
  *
  * Code for handling interrupted transfers.  Depending on the @c
@@ -115,6 +141,7 @@ void _exit_cleanup(int code, const char *file, int line)
 		rprintf(FINFO,"_exit_cleanup(code=%d, file=%s, line=%d): about to call exit(%d)\n", 
 			ocode, file, line, code);
 
+	close_all();
 	exit(code);
 }
 
diff --git a/configure.in b/configure.in
index 31fd57d2..843fe60b 100644
--- a/configure.in
+++ b/configure.in
@@ -256,6 +256,14 @@ AC_MSG_RESULT($DEFAULT_MODIFY_WINDOW)
 AC_DEFINE_UNQUOTED(DEFAULT_MODIFY_WINDOW, $DEFAULT_MODIFY_WINDOW,
 	[Set to the default value for the --modify-window option])
 
+AC_MSG_CHECKING([whether to call shutdown on all sockets])
+case $host_os in
+	*cygwin* ) AC_MSG_RESULT(yes)
+                   AC_DEFINE(SHUTDOWN_ALL_SOCKETS, 1, [Define if sockets need to be shutdown])
+		   ;;
+	       * ) AC_MSG_RESULT(no);;
+esac
+
 AC_C_BIGENDIAN
 AC_HEADER_DIRENT
 AC_HEADER_TIME
diff --git a/socket.c b/socket.c
index fa8e4572..eb0660bb 100644
--- a/socket.c
+++ b/socket.c
@@ -429,11 +429,14 @@ void start_accept_loop(int port, int (*fn)(int, int))
 #endif
 
 		if ((pid = fork()) == 0) {
+			int ret;
 			close(s);
 			/* open log file in child before possibly giving
 			   up privileges  */
 			log_open();
-			_exit(fn(fd, fd));
+			ret = fn(fd, fd);
+			close_all();
+			_exit(ret);
 		} else if (pid < 0) {
 			rprintf(FERROR,
 				RSYNC_NAME