From 5d8d99be048899c0438dab4e726238eb97b0440f Mon Sep 17 00:00:00 2001
From: "kfraser@localhost.localdomain" <kfraser@localhost.localdomain>
Date: Thu, 1 Mar 2007 14:51:12 +0000
Subject: [PATCH] Fully reset the xenstore connection when a domain is
 (re)introduced to xenstored. Signed-off-by: Keir Fraser <keir@xensource.com>

---
 tools/xenstore/xenstored_domain.c      | 27 ++++++++++++++++++++++----
 tools/xenstore/xenstored_transaction.c | 16 +++++++++++++++
 tools/xenstore/xenstored_transaction.h |  3 +++
 tools/xenstore/xenstored_watch.c       | 11 +++++++++++
 tools/xenstore/xenstored_watch.h       |  2 ++
 5 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c
index ba3507fdfc..5249ef6d56 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -28,6 +28,7 @@
 #include "talloc.h"
 #include "xenstored_core.h"
 #include "xenstored_domain.h"
+#include "xenstored_transaction.h"
 #include "xenstored_watch.h"
 #include "xenstored_test.h"
 
@@ -289,6 +290,26 @@ static struct domain *find_domain_by_domid(unsigned int domid)
 	return NULL;
 }
 
+static void domain_conn_reset(struct domain *domain)
+{
+	struct connection *conn = domain->conn;
+	struct buffered_data *out;
+
+	conn_delete_all_watches(conn);
+	conn_delete_all_transactions(conn);
+
+	while ((out = list_top(&conn->out_list, struct buffered_data, list))) {
+		list_del(&out->list);
+		talloc_free(out);
+	}
+
+	talloc_free(conn->in->buffer);
+	memset(conn->in, 0, sizeof(*conn->in));
+	conn->in->inhdr = true;
+
+	domain->interface->req_cons = domain->interface->req_prod = 0;
+	domain->interface->rsp_cons = domain->interface->rsp_prod = 0;
+}
 
 /* domid, mfn, evtchn, path */
 void do_introduce(struct connection *conn, struct buffered_data *in)
@@ -342,7 +363,7 @@ void do_introduce(struct connection *conn, struct buffered_data *in)
 		talloc_steal(domain->conn, domain);
 
 		fire_watches(conn, "@introduceDomain", false);
-	} else if (domain->mfn == mfn) {
+	} else if ((domain->mfn == mfn) && (domain->conn != conn)) {
 		/* Use XS_INTRODUCE for recreating the xenbus event-channel. */
 		if (domain->port)
 			xc_evtchn_unbind(xce_handle, domain->port);
@@ -354,9 +375,7 @@ void do_introduce(struct connection *conn, struct buffered_data *in)
 		return;
 	}
 
-	/* Rings must be quiesced. */
-	domain->interface->req_cons = domain->interface->req_prod = 0;
-	domain->interface->rsp_cons = domain->interface->rsp_prod = 0;
+	domain_conn_reset(domain);
 
 	send_ack(conn, XS_INTRODUCE);
 }
diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c
index 69cc520bb9..cf10ecc348 100644
--- a/tools/xenstore/xenstored_transaction.c
+++ b/tools/xenstore/xenstored_transaction.c
@@ -23,6 +23,7 @@
 #include <sys/wait.h>
 #include <sys/time.h>
 #include <time.h>
+#include <assert.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <fcntl.h>
@@ -211,6 +212,21 @@ void do_transaction_end(struct connection *conn, const char *arg)
 	send_ack(conn, XS_TRANSACTION_END);
 }
 
+void conn_delete_all_transactions(struct connection *conn)
+{
+	struct transaction *trans;
+
+	while ((trans = list_top(&conn->transaction_list,
+				 struct transaction, list))) {
+		list_del(&trans->list);
+		talloc_free(trans);
+	}
+
+	assert(conn->transaction == NULL);
+
+	conn->transaction_started = 0;
+}
+
 /*
  * Local variables:
  *  c-file-style: "linux"
diff --git a/tools/xenstore/xenstored_transaction.h b/tools/xenstore/xenstored_transaction.h
index 1fc30dff50..ecbae47f2d 100644
--- a/tools/xenstore/xenstored_transaction.h
+++ b/tools/xenstore/xenstored_transaction.h
@@ -33,4 +33,7 @@ void add_change_node(struct transaction *trans, const char *node,
 
 /* Return tdb context to use for this connection. */
 TDB_CONTEXT *tdb_transaction_context(struct transaction *trans);
+
+void conn_delete_all_transactions(struct connection *conn);
+
 #endif /* _XENSTORED_TRANSACTION_H */
diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c
index 3de6e7ace8..4d1a6d5bfb 100644
--- a/tools/xenstore/xenstored_watch.c
+++ b/tools/xenstore/xenstored_watch.c
@@ -185,6 +185,17 @@ void do_unwatch(struct connection *conn, struct buffered_data *in)
 	send_error(conn, ENOENT);
 }
 
+void conn_delete_all_watches(struct connection *conn)
+{
+	struct watch *watch;
+
+	while ((watch = list_top(&conn->watches, struct watch, list))) {
+		list_del(&watch->list);
+		talloc_free(watch);
+		domain_watch_dec(conn);
+	}
+}
+
 #ifdef TESTING
 void dump_watches(struct connection *conn)
 {
diff --git a/tools/xenstore/xenstored_watch.h b/tools/xenstore/xenstored_watch.h
index 2eccff9476..6125ff3886 100644
--- a/tools/xenstore/xenstored_watch.h
+++ b/tools/xenstore/xenstored_watch.h
@@ -30,4 +30,6 @@ void fire_watches(struct connection *conn, const char *name, bool recurse);
 
 void dump_watches(struct connection *conn);
 
+void conn_delete_all_watches(struct connection *conn);
+
 #endif /* _XENSTORED_WATCH_H */
-- 
2.30.2