1 // Copyright 2021 Google LLC
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //      http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #include "handler.hpp"
16 
17 #include <blobs-ipmid/blobs.hpp>
18 
19 #include <memory>
20 
21 // Extern "C" is used due to the usage of dlopen() for loading IPMI handlers
22 // and IPMI blob handlers. This happens in two steps:
23 //
24 // 1) ipmid loads all libraries in /usr/lib/ipmid-providers from its
25 //    loadLibraries() function using dlopen().
26 // 2) The blobs library, libblobcmds.so, loads all libraries in
27 //    /usr/lib/blobs-ipmid from its loadLibraries() function. It uses dlsym()
28 //    to locate the createHandler function by its un-mangled name
29 //    "createHandler". Using extern "C" prevents its name from being mangled
30 //    into, for example, "_Z13createHandlerv".
31 
32 extern "C" std::unique_ptr<blobs::GenericBlobInterface> createHandler()
33 {
34     return std::make_unique<blobs::MetricBlobHandler>();
35 }
36