bus/containers: Do some basic checking on the parameters

In particular, we now fail early if we can't extract the file
descriptor, or if there are named parameters (none are supported yet).

Signed-off-by: Simon McVittie <smcv@collabora.com>
Reviewed-by: Philip Withnall <withnall@endlessm.com>
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=101354

diff --git a/bus/containers.c b/bus/containers.c
index e8935490c7dbf062dd3e2f4f936e95517e8102f3..cf9156f4b42e8032394e9038cfd80b55c4f33c2e 100644 (file)
--- a/bus/containers.c
+++ b/bus/containers.c
@@ -29,13 +29,86 @@
 # error DBUS_ENABLE_CONTAINERS requires DBUS_UNIX
 #endif
 
+#include "dbus/dbus-internals.h"
+#include "dbus/dbus-sysdeps-unix.h"
+
 dbus_bool_t
 bus_containers_handle_add_server (DBusConnection *connection,
                                   BusTransaction *transaction,
                                   DBusMessage    *message,
                                   DBusError      *error)
 {
+  DBusMessageIter iter;
+  DBusMessageIter dict_iter;
+  const char *type;
+  const char *name;
+
+  /* We already checked this in bus_driver_handle_message() */
+  _dbus_assert (dbus_message_has_signature (message, "ssa{sv}a{sv}"));
+
+  /* Argument 0: Container type */
+  if (!dbus_message_iter_init (message, &iter))
+    _dbus_assert_not_reached ("Message type was already checked");
+
+  _dbus_assert (dbus_message_iter_get_arg_type (&iter) == DBUS_TYPE_STRING);
+  dbus_message_iter_get_basic (&iter, &type);
+
+  if (!dbus_validate_interface (type, NULL))
+    {
+      dbus_set_error (error, DBUS_ERROR_INVALID_ARGS,
+                      "The container type identifier must have the "
+                      "syntax of an interface name");
+      goto fail;
+    }
+
+  /* Argument 1: Name as defined by container manager */
+  if (!dbus_message_iter_next (&iter))
+    _dbus_assert_not_reached ("Message type was already checked");
+
+  _dbus_assert (dbus_message_iter_get_arg_type (&iter) == DBUS_TYPE_STRING);
+  dbus_message_iter_get_basic (&iter, &name);
+
+  /* Argument 2: Metadata as defined by container manager */
+  if (!dbus_message_iter_next (&iter))
+    _dbus_assert_not_reached ("Message type was already checked");
+
+  _dbus_assert (dbus_message_iter_get_arg_type (&iter) == DBUS_TYPE_ARRAY);
+  /* TODO: Copy the metadata */
+
+  /* Argument 3: Named parameters */
+  if (!dbus_message_iter_next (&iter))
+    _dbus_assert_not_reached ("Message type was already checked");
+
+  _dbus_assert (dbus_message_iter_get_arg_type (&iter) == DBUS_TYPE_ARRAY);
+  dbus_message_iter_recurse (&iter, &dict_iter);
+
+  while (dbus_message_iter_get_arg_type (&dict_iter) != DBUS_TYPE_INVALID)
+    {
+      DBusMessageIter pair_iter;
+      const char *param_name;
+
+      _dbus_assert (dbus_message_iter_get_arg_type (&dict_iter) ==
+                    DBUS_TYPE_DICT_ENTRY);
+
+      dbus_message_iter_recurse (&dict_iter, &pair_iter);
+      _dbus_assert (dbus_message_iter_get_arg_type (&pair_iter) ==
+                    DBUS_TYPE_STRING);
+      dbus_message_iter_get_basic (&pair_iter, &param_name);
+
+      /* If we supported any named parameters, we'd copy them into a data
+       * structure here; but we don't, so fail instead. */
+      dbus_set_error (error, DBUS_ERROR_INVALID_ARGS,
+                      "Named parameter %s is not understood", param_name);
+      goto fail;
+    }
+
+  /* End of arguments */
+  _dbus_assert (!dbus_message_iter_has_next (&iter));
+
+  /* TODO: Actually implement the method */
   dbus_set_error (error, DBUS_ERROR_NOT_SUPPORTED, "Not yet implemented");
+
+fail:
   return FALSE;
 }