proto: Don't drop outgoing message when daemon cancels (RHBZ#576879).

[libguestfs.git] / src / proto.c

diff --git a/src/proto.c b/src/proto.c
index 1be7e05..2ca24c2 100644 (file)
--- a/src/proto.c
+++ b/src/proto.c
@@ -449,8 +449,19 @@ guestfs___send_to_daemon (guestfs_h *g, const void *v_buf, size_t n)
     }
     if (FD_ISSET (g->sock, &rset2)) {
       r = check_for_daemon_cancellation_or_eof (g, g->sock);
     }
     if (FD_ISSET (g->sock, &rset2)) {
       r = check_for_daemon_cancellation_or_eof (g, g->sock);

-      if (r < 0)
-        return r;
+      if (r == -1)
+       return r;
+      if (r == -2) {
+       /* Daemon sent cancel message.  But to maintain
+        * synchronization we must write out the remainder of the
+        * write buffer before we return (RHBZ#576879).
+        */
+       if (xwrite (g->sock, buf, n) == -1) {
+         perrorf (g, "write");
+         return -1;
+       }
+       return -2; /* cancelled */
+      }

     }
     if (FD_ISSET (g->sock, &wset2)) {
       r = write (g->sock, buf, n);
     }
     if (FD_ISSET (g->sock, &wset2)) {
       r = write (g->sock, buf, n);