xref: /openbmc/google-ipmi-sys/util.cpp (revision 444b5ea4)
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 "util.hpp"
16 
17 #include <nlohmann/json.hpp>
18 #include <phosphor-logging/elog-errors.hpp>
19 #include <xyz/openbmc_project/Common/error.hpp>
20 
21 #include <cstdint>
22 #include <cstdio>
23 #include <filesystem>
24 #include <fstream>
25 #include <regex>
26 #include <string>
27 #include <tuple>
28 #include <vector>
29 
30 namespace google
31 {
32 namespace ipmi
33 {
34 namespace fs = std::filesystem;
35 using namespace phosphor::logging;
36 using InternalFailure =
37     sdbusplus::xyz::openbmc_project::Common::Error::InternalFailure;
38 
39 nlohmann::json parseConfig(const std::string& file)
40 {
41     std::ifstream jsonFile(file);
42     if (!jsonFile.is_open())
43     {
44         log<level::ERR>("Entity association JSON file not found");
45         elog<InternalFailure>();
46     }
47 
48     auto data = nlohmann::json::parse(jsonFile, nullptr, false);
49     if (data.is_discarded())
50     {
51         log<level::ERR>("Entity association JSON parser failure");
52         elog<InternalFailure>();
53     }
54 
55     return data;
56 }
57 
58 std::string readPropertyFile(const std::string& fileName)
59 {
60     std::ifstream ifs(fileName);
61     std::string contents;
62 
63     if (!ifs.is_open())
64     {
65         auto msg = std::string("Unable to open file ") + fileName.c_str();
66         log<level::DEBUG>(msg.c_str());
67     }
68     else
69     {
70         if (ifs >> contents)
71         {
72             // If the last character is a null terminator; remove it.
73             if (!contents.empty())
74             {
75                 const char& back = contents.back();
76                 if (back == '\0')
77                     contents.pop_back();
78             }
79 
80             return contents;
81         }
82         else
83         {
84             std::fprintf(stderr, "Unable to read file %s.\n", fileName.c_str());
85         }
86     }
87 
88     return "";
89 }
90 
91 std::vector<std::tuple<std::uint32_t, std::string>> buildPcieMap()
92 {
93     std::vector<std::tuple<std::uint32_t, std::string>> pcie_i2c_map;
94 
95     // Build a vector with i2c bus to pcie slot mapping.
96     // Iterate through all the devices under "/sys/bus/i2c/devices".
97     for (const auto& i2c_dev : fs::directory_iterator("/sys/bus/i2c/devices"))
98     {
99         std::string i2c_dev_path = i2c_dev.path();
100         std::smatch i2c_dev_string_number;
101         std::regex e("(i2c-)(\\d+)");
102 
103         // Check if the device has "i2c-" in its path.
104         if (std::regex_search(i2c_dev_path, i2c_dev_string_number, e))
105         {
106             // Check if the i2c device has "pcie-slot" file under "of-node" dir.
107             std::string pcie_slot_path = i2c_dev_path + "/of_node/pcie-slot";
108             std::string pcie_slot;
109 
110             // Read the "pcie-slot" name from the "pcie-slot" file.
111             pcie_slot = readPropertyFile(pcie_slot_path);
112             if (pcie_slot.empty())
113             {
114                 continue;
115             }
116             std::string pcie_slot_name;
117             std::string pcie_slot_full_path;
118 
119             // Append the "pcie-slot" name to dts base.
120             pcie_slot_full_path.append("/proc/device-tree");
121             pcie_slot_full_path.append(pcie_slot);
122 
123             // Read the "label" which contains the pcie slot name.
124             pcie_slot_full_path.append("/label");
125             pcie_slot_name = readPropertyFile(pcie_slot_full_path);
126 
127             if (pcie_slot_name.empty())
128             {
129                 continue;
130             }
131 
132             // Get the i2c bus number from the i2c device path.
133             std::uint32_t i2c_bus_number =
134                 i2c_dev_string_number[2].matched
135                     ? std::stoi(i2c_dev_string_number[2])
136                     : 0;
137             // Store the i2c bus number and the pcie slot name in the vector.
138             pcie_i2c_map.push_back(
139                 std::make_tuple(i2c_bus_number, pcie_slot_name));
140         }
141     }
142 
143     return pcie_i2c_map;
144 }
145 
146 } // namespace ipmi
147 } // namespace google
148