xref: /openbmc/phosphor-logging/util.cpp (revision 1894199f)
1 /**
2  * Copyright © 2020 IBM Corporation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 #include "config.h"
17 
18 #include "util.hpp"
19 
20 namespace phosphor::logging::util
21 {
22 
23 std::optional<std::string> getOSReleaseValue(const std::string& key)
24 {
25     std::ifstream versionFile{BMC_VERSION_FILE};
26     std::string line;
27     std::string keyPattern{key + '='};
28 
29     while (std::getline(versionFile, line))
30     {
31         if (line.substr(0, keyPattern.size()).find(keyPattern) !=
32             std::string::npos)
33         {
34             // If the value isn't surrounded by quotes, then pos will be
35             // npos + 1 = 0, and the 2nd arg to substr() will be npos
36             // which means get the rest of the string.
37             auto value = line.substr(keyPattern.size());
38             std::size_t pos = value.find_first_of('"') + 1;
39             return value.substr(pos, value.find_last_of('"') - pos);
40         }
41     }
42 
43     return std::nullopt;
44 }
45 
46 } // namespace phosphor::logging::util
47