Set our stderr output to blocking I/O to avoid any loss of output.

diff --git a/main.c b/main.c
index 4f3fd90..03af24b 100644 (file)
--- a/main.c
+++ b/main.c
@@ -657,6 +657,16 @@ int client_run(int f_in, int f_out, pid_t pid, int argc, char *argv[])
        if (protocol_version >= 23 && !read_batch)
                io_start_multiplex_in();
 
+       /* We set our stderr file handle to blocking because ssh might have
+        * set it to non-blocking.  This can be particularly troublesome if
+        * stderr is a clone of stdout, because ssh would have set our stdout
+        * to non-blocking at the same time (which can easily cause us to lose
+        * output from our print statements).  This kluge shouldn't cause ssh
+        * any problems for how we use it.  Note also that we delayed setting
+        * this until after the above protocol setup so that we know for sure
+        * that ssh is done twiddling its file descriptors.  */
+       set_blocking(STDERR_FILENO);
+
        if (am_sender) {
                keep_dirlinks = 0; /* Must be disabled on the sender. */
                io_start_buffering_out();