From d83ce91fd4492c9267ffd2516dc24418b170a572 Mon Sep 17 00:00:00 2001
From: "Daniel P. Berrange" <berrange@redhat.com>
Date: Tue, 11 Nov 2014 18:39:19 +0000
Subject: [PATCH] Add systemd/dtrace probes for DBus APIs

When debugging libvirt it is helpful to set probes around RPC
calls. We already have probes for libvirt's native RPC layer,
so it makes sense to add them for the DBus RPC layer too.
---
 src/libvirt_probes.d |  5 +++++
 src/util/virdbus.c   | 26 +++++++++++++++++++++++---
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/src/libvirt_probes.d b/src/libvirt_probes.d
index 340d665e82..c5bda5c974 100644
--- a/src/libvirt_probes.d
+++ b/src/libvirt_probes.d
@@ -15,6 +15,11 @@ provider libvirt {
 
 	probe event_poll_run(int nfds, int timeout);
 
+	# file: src/util/virdbus.c
+	# prefix: dbus
+	probe dbus_method_call(const char *interface, const char *member, const char *object, const char *destination);
+	probe dbus_method_error(const char *interface, const char *member, const char *object, const char *destination, const char *name, const char *message);
+	probe dbus_method_reply(const char *interface, const char *member, const char *object, const char *destination);
 
         # file: src/util/virobject.c
         # prefix: object
diff --git a/src/util/virdbus.c b/src/util/virdbus.c
index ee8732c233..d9665c1f7f 100644
--- a/src/util/virdbus.c
+++ b/src/util/virdbus.c
@@ -27,6 +27,7 @@
 #include "virlog.h"
 #include "virthread.h"
 #include "virstring.h"
+#include "virprobe.h"
 
 #define VIR_FROM_THIS VIR_FROM_DBUS
 
@@ -1521,20 +1522,35 @@ static int
 virDBusCall(DBusConnection *conn,
             DBusMessage *call,
             DBusMessage **replyout,
-            DBusError *error,
-            const char *member)
+            DBusError *error)
+
 {
     DBusMessage *reply = NULL;
     DBusError localerror;
     int ret = -1;
+    const char *iface, *member, *path, *dest;
 
     if (!error)
         dbus_error_init(&localerror);
 
+    iface = dbus_message_get_interface(call);
+    member = dbus_message_get_member(call);
+    path = dbus_message_get_path(call);
+    dest = dbus_message_get_destination(call);
+
+    PROBE(DBUS_METHOD_CALL,
+          "'%s.%s' on '%s' at '%s'",
+          iface, member, path, dest);
+
     if (!(reply = dbus_connection_send_with_reply_and_block(conn,
                                                             call,
                                                             VIR_DBUS_METHOD_CALL_TIMEOUT_MILLIS,
                                                             error ? error : &localerror))) {
+        PROBE(DBUS_METHOD_ERROR,
+              "'%s.%s' on '%s' at '%s' error %s: %s",
+              iface, member, path, dest,
+              error ? error->name : localerror.name,
+              error ? error->message : localerror.message);
         if (error) {
             ret = 0;
         } else {
@@ -1544,6 +1560,10 @@ virDBusCall(DBusConnection *conn,
         goto cleanup;
     }
 
+    PROBE(DBUS_METHOD_REPLY,
+          "'%s.%s' on '%s' at '%s'",
+          iface, member, path, dest);
+
     ret = 0;
 
  cleanup:
@@ -1616,7 +1636,7 @@ int virDBusCallMethod(DBusConnection *conn,
 
     ret = -1;
 
-    ret = virDBusCall(conn, call, replyout, error, member);
+    ret = virDBusCall(conn, call, replyout, error);
 
  cleanup:
     if (call)
-- 
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