Kill pg_basebackup background process when exiting

If an error occurs in the foreground (backup) process of pg_basebackup,
and we exit in a controlled way, the background process (streaming
xlog process) would stay around and keep streaming.

src/bin/pg_basebackup/pg_basebackup.c

@@ -72,6 +72,7 @@ static volatile LONG has_xlogendptr = 0;
 
 /* Function headers */
 static void usage(void);
+static void disconnect_and_exit(int code);
 static void verify_dir_is_empty_or_create(char *dirname);
 static void progress_report(int tablespacenum, const char *filename);
 
@@ -82,6 +83,26 @@ static void BaseBackup(void);
 static bool reached_end_position(XLogRecPtr segendpos, uint32 timeline,
 					 bool segment_finished);
 
+
+static void disconnect_and_exit(int code)
+{
+	if (conn != NULL)
+		PQfinish(conn);
+
+#ifndef WIN32
+	/*
+	 * On windows, our background thread dies along with the process.
+	 * But on Unix, if we have started a subprocess, we want to kill
+	 * it off so it doesn't remain running trying to stream data.
+	 */
+	if (bgchild> 0)
+		kill(bgchild, SIGTERM);
+#endif
+
+	exit(code);
+}
+
+
 #ifdef HAVE_LIBZ
 static const char *
 get_gz_error(gzFile gzf)

src/bin/pg_basebackup/pg_receivexlog.c

@@ -51,6 +51,13 @@ static void StreamLog();
 static bool stop_streaming(XLogRecPtr segendpos, uint32 timeline,
 			   bool segment_finished);
 
+#define disconnect_and_exit(code)				\
+	{											\
+	if (conn != NULL) PQfinish(conn);			\
+	exit(code);									\
+	}
+
+
 static void
 usage(void)
 {

src/bin/pg_basebackup/streamutil.h

@@ -9,13 +9,6 @@ extern int	dbgetpassword;
 /* Connection kept global so we can disconnect easily */
 extern PGconn *conn;
 
-#define disconnect_and_exit(code)				\
-	{											\
-	if (conn != NULL) PQfinish(conn);			\
-	exit(code);									\
-	}
-
-
 char	   *xstrdup(const char *s);
 void	   *xmalloc0(int size);