libxl: libxl: Introduce dm-version xenstore key.

The all key is /libxl/$domid/dm-version.

The /libxl/$domid dir is created with the domain and should be only accessible
by the toolstack domain. The function libxl__xs_libxl_path() give this path.

This come with libxl__device_model_version_running() helper function.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/tools/libxl/libxl_internal.c b/tools/libxl/libxl_internal.c
index 3993d8e333..34edaf384d 100644
--- a/tools/libxl/libxl_internal.c
+++ b/tools/libxl/libxl_internal.c
@@ -319,6 +319,29 @@ int libxl__fd_set_cloexec(int fd)
     return fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 }
 
+libxl_device_model_version libxl__device_model_version_running(libxl__gc *gc,
+                                                               uint32_t domid)
+{
+    char *path = NULL;
+    char *dm_version = NULL;
+    libxl_device_model_version value;
+
+    path = libxl__xs_libxl_path(gc, domid);
+    path = libxl__sprintf(gc, "%s/dm-version", path);
+    dm_version = libxl__xs_read(gc, XBT_NULL, path);
+    if (!dm_version) {
+        return LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL;
+    }
+
+    if (libxl_device_model_version_from_string(dm_version, &value) < 0) {
+        libxl_ctx *ctx = libxl__gc_owner(gc);
+        LIBXL__LOG(ctx, LIBXL__LOG_ERROR,
+                   "fatal: %s contain a wrong value (%s)", path, dm_version);
+        return -1;
+    }
+    return value;
+}
+
 /*
  * Local variables:
  * mode: C