[Libguestfs] [PATCH] Protocol changes to support upload progress messages and optional arguments.
Richard W.M. Jones
rjones at redhat.com
Wed Dec 1 10:31:52 UTC 2010
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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-------------- next part --------------
>From 4c7ca014212acfbe7800f5988cf9054b011f4273 Mon Sep 17 00:00:00 2001
From: Richard W.M. Jones <rjones at redhat.com>
Date: Wed, 1 Dec 2010 10:30:44 +0000
Subject: [PATCH] Protocol changes to support upload progress messages and optional arguments.
---
daemon/proto.c | 28 ++++++++++++++++++++++++++++
generator/generator_xdr.ml | 4 +++-
src/guestfs.pod | 8 ++++++++
src/proto.c | 2 ++
4 files changed, 41 insertions(+), 1 deletions(-)
diff --git a/daemon/proto.c b/daemon/proto.c
index 63d1cc9..f3a3b26 100644
--- a/daemon/proto.c
+++ b/daemon/proto.c
@@ -22,6 +22,7 @@
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
+#include <inttypes.h>
#include <unistd.h>
#include <errno.h>
#include <sys/param.h> /* defines MIN */
@@ -45,6 +46,23 @@
int proc_nr;
int serial;
+/* Hint for implementing progress messages for uploaded/incoming data.
+ * The caller sets this to a value > 0 if it knows or can estimate how
+ * much data will be sent (this is not always known, eg. for uploads
+ * coming from a pipe). If this is known then we can emit progress
+ * messages as we write the data.
+ */
+uint64_t progress_hint;
+
+/* Optional arguments bitmask. Caller sets this to indicate which
+ * optional arguments in the guestfs_<foo>_args structure are
+ * meaningful. Optional arguments not covered by the bitmask are set
+ * to arbitrary values and the daemon should ignore them. If the
+ * bitmask has bits set that the daemon doesn't understand, then the
+ * whole call is rejected early in processing.
+ */
+uint64_t optargs_bitmask;
+
/* Time at which we received the current request. */
static struct timeval start_t;
@@ -149,9 +167,19 @@ main_loop (int _sock)
reply_with_error ("unexpected message status (%d)", hdr.status);
goto cont;
}
+ /* This version of the daemon does not understand optional arguments
+ * at all. When we fix this, we will remove the next conditional.
+ */
+ if (hdr.optargs_bitmask != 0) {
+ reply_with_error ("optargs_bitmask != 0 (%" PRIu64 ")",
+ hdr.optargs_bitmask);
+ goto cont;
+ }
proc_nr = hdr.proc;
serial = hdr.serial;
+ progress_hint = hdr.progress_hint;
+ optargs_bitmask = hdr.optargs_bitmask;
/* Clear errors before we call the stub functions. This is just
* to ensure that we can accurately report errors in cases where
diff --git a/generator/generator_xdr.ml b/generator/generator_xdr.ml
index c6d8a4d..ca114c5 100644
--- a/generator/generator_xdr.ml
+++ b/generator/generator_xdr.ml
@@ -158,7 +158,7 @@ let generate_xdr () =
*/
const GUESTFS_PROGRAM = 0x2000F5F5;
-const GUESTFS_PROTOCOL_VERSION = 3;
+const GUESTFS_PROTOCOL_VERSION = 4;
/* These constants must be larger than any possible message length. */
const GUESTFS_LAUNCH_FLAG = 0xf5f55ff5;
@@ -193,6 +193,8 @@ struct guestfs_message_header {
guestfs_procedure proc; /* GUESTFS_PROC_x */
guestfs_message_direction direction;
unsigned serial; /* message serial number */
+ unsigned hyper progress_hint; /* upload hint for progress bar */
+ unsigned hyper optargs_bitmask; /* bitmask for optional args */
guestfs_message_status status;
};
diff --git a/src/guestfs.pod b/src/guestfs.pod
index 677d944..7cb05a6 100644
--- a/src/guestfs.pod
+++ b/src/guestfs.pod
@@ -1855,6 +1855,14 @@ The header contains the procedure number (C<guestfs_proc>) which is
how the receiver knows what type of args structure to expect, or none
at all.
+For functions that take optional arguments, the optional arguments are
+encoded in the C<guestfs_I<foo>_args> structure in the same way as
+ordinary arguments. A bitmask in the header indicates which optional
+arguments are meaningful. The bitmask is also checked to see if it
+contains bits set which the daemon does not know about (eg. if more
+optional arguments were added in a later version of the library), and
+this causes the call to be rejected.
+
The reply message for ordinary functions is:
total length (header + ret,
diff --git a/src/proto.c b/src/proto.c
index 5d924e8..5c22e3d 100644
--- a/src/proto.c
+++ b/src/proto.c
@@ -658,6 +658,8 @@ guestfs___send (guestfs_h *g, int proc_nr, xdrproc_t xdrp, char *args)
hdr.direction = GUESTFS_DIRECTION_CALL;
hdr.serial = serial;
hdr.status = GUESTFS_STATUS_OK;
+ hdr.progress_hint = 0;
+ hdr.optargs_bitmask = 0;
if (!xdr_guestfs_message_header (&xdr, &hdr)) {
error (g, _("xdr_guestfs_message_header failed"));
--
1.7.3.2
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