1 /*
2  * Copyright (C) 2020 The Android Open Source Project
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 
17 #include "ServiceDescriptor.h"
18 
19 #include <array>
20 #include <memory>
21 
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 
26 ServiceDescriptor::ServiceDescriptor(std::string name, std::string cmd)
27     : mName(name), mCommandLine(cmd) {}
28 
29 std::optional<std::string> ServiceDescriptor::GetOutput(OutputConsumer* consumer) const {
30     if (!IsAvailable()) return "service not available";
31 
32     const auto cmd = command();
33 
34     int commandExitStatus = 0;
35     auto pipeStreamDeleter = [&commandExitStatus](std::FILE* fp) {
36         commandExitStatus = pclose(fp);
37     };
38     std::unique_ptr<std::FILE, decltype(pipeStreamDeleter)> pipeStream(popen(cmd, "r"),
39                                                                        pipeStreamDeleter);
40 
41     if (!pipeStream) {
42         return std::string("Failed to execute ") + cmd + ", " + strerror(errno);
43     }
44 
45     std::array<char, 65536> buffer;
46     while (!std::feof(pipeStream.get())) {
47         auto readLen = fread(buffer.data(), 1, buffer.size(), pipeStream.get());
48         consumer->Write(buffer.data(), readLen);
49     }
50 
51     pipeStream.reset();
52 
53     if (commandExitStatus == 0) {
54         return std::nullopt;
55     } else if (commandExitStatus < 0) {
56         return std::string("Failed when pclose ") + cmd + ", " + strerror(errno);
57     } else {
58         return std::string("Error when executing ") + cmd +
59                ", exit code: " + std::to_string(commandExitStatus);
60     }
61 }
62