[Xen-devel] [PATCH] xenstored: allow guests to shutdown all of its watches using XS_RESET

[Olaf Hering <olaf@xxxxxxxxx>]

# HG changeset patch
# User Olaf Hering <olaf@xxxxxxxxx>
# Date 1313090526 -7200
# Node ID 31687c9a9e3edfae7cf23483c8457b011dc4d843
# Parent  1f08b380d4386cdd6714786a9163e5f51aecab5d
xenstored: allow guests to shutdown all of its watches using XS_RESET

During kexec all old watches have to be removed, otherwise the new
kernel will receive unexpected events. Allow a guest to reset itself and
cleanup all of its watches.

Add a new XS_RESET command to do the reset on behalf of the guest.

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>

diff -r 1f08b380d438 -r 31687c9a9e3e tools/xenstore/xenstored_core.c
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -120,6 +120,7 @@ static char *sockmsg_string(enum xsd_soc
        case XS_IS_DOMAIN_INTRODUCED: return "XS_IS_DOMAIN_INTRODUCED";
        case XS_RESUME: return "RESUME";
        case XS_SET_TARGET: return "SET_TARGET";
+       case XS_RESET: return "RESET";
        default:
                return "**UNKNOWN**";
        }
@@ -1242,6 +1243,10 @@ static void process_message(struct conne
                do_set_target(conn, in);
                break;
 
+       case XS_RESET:
+               do_reset(conn, in);
+               break;
+
        default:
                eprintf("Client unknown operation %i", in->hdr.msg.type);
                send_error(conn, ENOSYS);
diff -r 1f08b380d438 -r 31687c9a9e3e tools/xenstore/xenstored_domain.c
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -537,6 +537,57 @@ void do_is_domain_introduced(struct conn
        send_reply(conn, XS_IS_DOMAIN_INTRODUCED, result ? "T" : "F", 2);
 }
 
+/* domid, mfn, evtchn, path */
+void do_reset(struct connection *conn, struct buffered_data *in)
+{
+       struct domain *domain;
+       char *vec[3];
+       unsigned int domid;
+       unsigned long mfn;
+       evtchn_port_t port;
+
+       if (!conn->can_write) {
+               send_error(conn, EACCES);
+               return;
+       }
+
+       if (get_strings(in, vec, ARRAY_SIZE(vec)) < ARRAY_SIZE(vec)) {
+               send_error(conn, EINVAL);
+               return;
+       }
+
+       domid = atoi(vec[0]);
+       mfn = atol(vec[1]);
+       port = atoi(vec[2]);
+
+       /* Sanity check args. */
+       if (port <= 0) {
+               send_error(conn, EINVAL);
+               return;
+       }
+       /* Allow guest to reset all watches */
+       if (domid != DOMID_SELF && conn->id != 0) {
+               send_error(conn, EACCES);
+               return;
+       }
+
+       domain = find_domain_by_domid(conn->id);
+
+       if (domain == NULL) {
+               send_error(conn, EINVAL);
+               return;
+       }
+
+       if (domain->mfn != mfn || domain->conn != conn || domain->port != port) 
{
+               send_error(conn, EACCES);
+               return;
+       }
+
+       domain_conn_reset(domain);
+
+       send_ack(conn, XS_RESET);
+}
+
 static int close_xc_handle(void *_handle)
 {
        xc_interface_close(*(xc_interface**)_handle);
diff -r 1f08b380d438 -r 31687c9a9e3e tools/xenstore/xenstored_domain.h
--- a/tools/xenstore/xenstored_domain.h
+++ b/tools/xenstore/xenstored_domain.h
@@ -40,6 +40,9 @@ void do_set_target(struct connection *co
 /* domid */
 void do_get_domain_path(struct connection *conn, const char *domid_str);
 
+/* domid, mfn, eventchn, path */
+void do_reset(struct connection *conn, struct buffered_data *in);
+
 void domain_init(void);
 
 /* Returns the implicit path of a connection (only domains have this) */
diff -r 1f08b380d438 -r 31687c9a9e3e xen/include/public/io/xs_wire.h
--- a/xen/include/public/io/xs_wire.h
+++ b/xen/include/public/io/xs_wire.h
@@ -48,7 +48,8 @@ enum xsd_sockmsg_type
     XS_IS_DOMAIN_INTRODUCED,
     XS_RESUME,
     XS_SET_TARGET,
-    XS_RESTRICT
+    XS_RESTRICT,
+    XS_RESET
 };
 
 #define XS_WRITE_NONE "NONE"

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