bios_setting: Add a read handler
Tested:
```
~# echo -n "01234567" > /run/oem_bios_setting
~# ipmitool raw 0x2e 0x32 0x79 0x2b 0x00 0x18
79 2b 00 18 08 30 31 32 33 34 35 36 37
~# rm /run/oem_bios_setting
~# ipmitool raw 0x2e 0x32 0x79 0x2b 0x00 0x18
Unable to send RAW command (channel=0x0 netfn=0x2e lun=0x0 cmd=0x32 rsp=0xca): Cannot return number of requested data bytes
```
Signed-off-by: Brandon Kim <brandonkim@google.com>
Change-Id: Icde2de4799a751634f56a580351bf10254dd7e4f
diff --git a/bios_setting.hpp b/bios_setting.hpp
new file mode 100644
index 0000000..7445a7a
--- /dev/null
+++ b/bios_setting.hpp
@@ -0,0 +1,38 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include "handler.hpp"
+
+#include <span>
+
+namespace google
+{
+namespace ipmi
+{
+
+#ifndef MAX_IPMI_BUFFER
+#define MAX_IPMI_BUFFER 64
+#endif
+
+// Max buffer - len
+constexpr size_t MAX_PAYLOAD_SIZE = MAX_IPMI_BUFFER - 1;
+
+Resp readBiosSetting(
+ std::span<const uint8_t> data, HandlerInterface* handler,
+ const std::string& biosSettingPath = "/run/oem_bios_setting");
+
+} // namespace ipmi
+} // namespace google