2 files changed, 111 insertions, 0 deletions

diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 6ce34fd67a..d8ce656f9d 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -527,6 +527,8 @@ _hidden int libxl__qmp_query_serial(libxl__qmp_handler *qmp);
 _hidden int libxl__qmp_pci_add(libxl__gc *gc, int d, libxl_device_pci *pcidev);
 _hidden int libxl__qmp_pci_del(libxl__gc *gc, int domid,
                                libxl_device_pci *pcidev);
+/* Save current QEMU state into fd. */
+_hidden int libxl__qmp_migrate(libxl__gc *gc, int domid, int fd);
 /* close and free the QMP handler */
 _hidden void libxl__qmp_close(libxl__qmp_handler *qmp);
 /* remove the socket file, if the file has already been removed,
diff --git a/tools/libxl/libxl_qmp.c b/tools/libxl/libxl_qmp.c
index 4c261369d5..4bc0dc87ae 100644
--- a/tools/libxl/libxl_qmp.c
+++ b/tools/libxl/libxl_qmp.c
@@ -532,6 +532,52 @@ out:
     return rc;
 }
 
+static int qmp_send_fd(libxl__gc *gc, libxl__qmp_handler *qmp,
+                       libxl_key_value_list *args,
+                       qmp_callback_t callback, void *opaque,
+                       qmp_request_context *context,
+                       int fd)
+{
+    struct msghdr msg = { 0 };
+    struct cmsghdr *cmsg;
+    char control[CMSG_SPACE(sizeof (fd))];
+    struct iovec iov;
+    char *buf = NULL;
+
+    buf = qmp_send_prepare(gc, qmp, "getfd", args, callback, opaque, context);
+
+    /* Response data */
+    iov.iov_base = buf;
+    iov.iov_len  = strlen(buf);
+
+    /* compose the message */
+    msg.msg_iov = &iov;
+    msg.msg_iovlen = 1;
+    msg.msg_control = control;
+    msg.msg_controllen = sizeof (control);
+
+    /* attach open fd */
+    cmsg = CMSG_FIRSTHDR(&msg);
+    cmsg->cmsg_level = SOL_SOCKET;
+    cmsg->cmsg_type = SCM_RIGHTS;
+    cmsg->cmsg_len = CMSG_LEN(sizeof (fd));
+    *(int *)CMSG_DATA(cmsg) = fd;
+
+    msg.msg_controllen = cmsg->cmsg_len;
+
+    if (sendmsg(qmp->qmp_fd, &msg, 0) < 0) {
+        LIBXL__LOG_ERRNO(qmp->ctx, LIBXL__LOG_ERROR,
+                         "Failed to send a QMP message to QEMU.");
+        return ERROR_FAIL;
+    }
+    if (libxl_write_exactly(qmp->ctx, qmp->qmp_fd, "\r\n", 2,
+                            "CRLF", "QMP socket")) {
+        return ERROR_FAIL;
+    }
+
+    return qmp->last_id_used;
+}
+
 static int qmp_synchronous_send(libxl__qmp_handler *qmp, const char *cmd,
                                 libxl_key_value_list *args,
                                 qmp_callback_t callback, void *opaque,
@@ -768,6 +814,69 @@ int libxl__qmp_pci_del(libxl__gc *gc, int domid, libxl_device_pci *pcidev)
     return qmp_device_del(gc, domid, id);
 }
 
+static int qmp_getfd(libxl__gc *gc, libxl__qmp_handler *qmp,
+                     int fd, const char *name)
+{
+    flexarray_t *parameters = NULL;
+    libxl_key_value_list args = NULL;
+    int rc = 0;
+
+    parameters = flexarray_make(2, 1);
+    if (!parameters)
+        return ERROR_NOMEM;
+    flexarray_append_pair(parameters, "fdname", (char*)name);
+    args = libxl__xs_kvs_of_flexarray(gc, parameters, parameters->count);
+    if (!args) {
+        rc = ERROR_NOMEM;
+        goto out;
+    }
+
+    if (qmp_send_fd(gc, qmp, &args, NULL, NULL, NULL, fd) < 0) {
+        rc = ERROR_FAIL;
+    }
+out:
+    flexarray_free(parameters);
+    return rc;
+}
+
+int libxl__qmp_migrate(libxl__gc *gc, int domid, int fd)
+{
+#define MIGRATE_FD_NAME "dm-migrate"
+    libxl__qmp_handler *qmp = NULL;
+    flexarray_t *parameters = NULL;
+    libxl_key_value_list args = NULL;
+    int rc = 0;
+
+    qmp = libxl__qmp_initialize(libxl__gc_owner(gc), domid);
+    if (!qmp)
+        return ERROR_FAIL;
+
+    rc = qmp_getfd(gc, qmp, fd, MIGRATE_FD_NAME);
+    if (rc)
+        goto out;
+
+    parameters = flexarray_make(2, 1);
+    if (!parameters) {
+        rc = ERROR_NOMEM;
+        goto out;
+    }
+    flexarray_append_pair(parameters, "uri", "fd:" MIGRATE_FD_NAME);
+    args = libxl__xs_kvs_of_flexarray(gc, parameters, parameters->count);
+    if (!args) {
+        rc = ERROR_NOMEM;
+        goto out2;
+    }
+
+    rc = qmp_synchronous_send(qmp, "migrate", &args,
+                              NULL, NULL, qmp->timeout);
+
+out2:
+    flexarray_free(parameters);
+out:
+    libxl__qmp_close(qmp);
+    return rc;
+}
+
 int libxl__qmp_initializations(libxl_ctx *ctx, uint32_t domid)
 {
     libxl__qmp_handler *qmp = NULL;