diff options
authoraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2008-10-13 03:10:22 +0000
committeraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2008-10-13 03:10:22 +0000
commit39b65c2e315ad5565e22b98ea2a4498ec2edfad2 (patch)
tree105b3e3f51cc09e4e940c695d2053e5eeb61e9b5 /buffered_file.h
parentFix some issues with QEMUFile (diff)
Introduce a buffered file wrapper for QEMUFile
This patch introduces a buffered QEMUFile wrapper. This allows QEMUFile's to be rate limited. It also makes it easier to implement a QEMUFile that is asynchronous since the current QEMUFile API requires that all reads and writes be synchronous. The only real non-obvious part of the API is the "frozen" concept. If the backend returns EAGAIN, the QEMUFile is said to be "frozen". This means no additional output will be sent to the backend until the file is unfrozen. qemu_file_put_notify can be used to unfreeze a frozen file. A synchronous interface is also provided to wait for an unfreeze event. This is used during the final part of live migration when the VM is no longer running. Signed-off-by: Anthony Liguori <> git-svn-id: svn:// c046a42c-6fe2-441c-8c8c-71466251a162
Diffstat (limited to 'buffered_file.h')
1 files changed, 30 insertions, 0 deletions
diff --git a/buffered_file.h b/buffered_file.h
new file mode 100644
index 000000000..98d358bae
--- /dev/null
+++ b/buffered_file.h
@@ -0,0 +1,30 @@
+ * QEMU buffered QEMUFile
+ *
+ * Copyright IBM, Corp. 2008
+ *
+ * Authors:
+ * Anthony Liguori <>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ *
+ */
+#include "hw/hw.h"
+typedef ssize_t (BufferedPutFunc)(void *opaque, const void *data, size_t size);
+typedef void (BufferedPutReadyFunc)(void *opaque);
+typedef void (BufferedWaitForUnfreezeFunc)(void *opaque);
+typedef int (BufferedCloseFunc)(void *opaque);
+QEMUFile *qemu_fopen_ops_buffered(void *opaque, size_t xfer_limit,
+ BufferedPutFunc *put_buffer,
+ BufferedPutReadyFunc *put_ready,
+ BufferedWaitForUnfreezeFunc *wait_for_unfreeze,
+ BufferedCloseFunc *close);