migration: introduce set_blocking function in QEMUFileOps

Remove the assumption that every QEMUFile implementation has
a file descriptor available by introducing a new function
in QEMUFileOps to change the blocking state of a QEMUFile.

If not set, it will fallback to the original code using
the get_fd method.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <1461751518-12128-7-git-send-email-berrange@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
index 1934a64a64..2dea81f21e 100644
--- a/include/migration/qemu-file.h
+++ b/include/migration/qemu-file.h
@@ -54,6 +54,10 @@ typedef int (QEMUFileCloseFunc)(void *opaque);
  */
 typedef int (QEMUFileGetFD)(void *opaque);
 
+/* Called to change the blocking mode of the file
+ */
+typedef int (QEMUFileSetBlocking)(void *opaque, bool enabled);
+
 /*
  * This function writes an iovec to file. The handler must write all
  * of the data or return a negative errno value.
@@ -107,6 +111,7 @@ typedef struct QEMUFileOps {
     QEMUFileGetBufferFunc *get_buffer;
     QEMUFileCloseFunc *close;
     QEMUFileGetFD *get_fd;
+    QEMUFileSetBlocking *set_blocking;
     QEMUFileWritevBufferFunc *writev_buffer;
     QEMURetPathFunc *get_return_path;
     QEMUFileShutdownFunc *shut_down;