1 /* 2 * Copyright (C) 2021 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 #pragma once 18 19 #include <optional> 20 #include <ostream> 21 #include <string> 22 #include <variant> 23 #include <vector> 24 25 #include <android-base/macros.h> 26 #include <android-base/result.h> 27 #include <android-base/unique_fd.h> 28 29 /** 30 * Log a lot more information about host-device binder communication, when debugging issues. 31 */ 32 #define SHOULD_LOG_HOST false 33 34 #if SHOULD_LOG_HOST 35 #define LOG_HOST(...) ALOGI(__VA_ARGS__) 36 #else 37 #define LOG_HOST(...) ALOGV(__VA_ARGS__) // for type checking 38 #endif 39 40 namespace android { 41 42 struct CommandResult { 43 std::optional<int32_t> exitCode; 44 std::optional<int32_t> signal; 45 std::optional<pid_t> pid; 46 std::string stdoutStr; 47 std::string stderrStr; 48 49 android::base::unique_fd outPipe; 50 android::base::unique_fd errPipe; 51 52 CommandResult() = default; CommandResultCommandResult53 CommandResult(CommandResult&& other) noexcept { (*this) = std::move(other); } 54 CommandResult& operator=(CommandResult&& other) noexcept { 55 std::swap(exitCode, other.exitCode); 56 std::swap(signal, other.signal); 57 std::swap(pid, other.pid); 58 std::swap(stdoutStr, other.stdoutStr); 59 std::swap(stderrStr, other.stderrStr); 60 return *this; 61 } 62 ~CommandResult(); 63 [[nodiscard]] std::string toString() const; 64 stdoutEndsWithNewLineCommandResult65 [[nodiscard]] bool stdoutEndsWithNewLine() const { 66 return !stdoutStr.empty() && stdoutStr.back() == '\n'; 67 } 68 69 private: 70 DISALLOW_COPY_AND_ASSIGN(CommandResult); 71 }; 72 73 std::ostream& operator<<(std::ostream& os, const CommandResult& res); 74 75 // Execute a command using tokens specified in @a argStringVec. 76 // 77 // @a end is a predicate checked periodically when the command emits any output to stdout or 78 // stderr. When it is evaluated to true, the function returns immediately even though 79 // the child process has not been terminated. The function also assumes that, after @a end 80 // is evaluated to true, the child process does not emit any other messages. 81 // If this is not the case, caller to execute() must handle these I/O in the pipes in the returned 82 // CommandResult object. Otherwise the child program may hang on I/O. 83 // 84 // If @a end is nullptr, it is equivalent to a predicate that always returns false. In this 85 // case, execute() returns after the child process is terminated. 86 // 87 // If @a end is evaluated to true, and execute() returns with the child process running, 88 // the returned CommandResult has pid, outPipe, and errPipe set. In this case, the caller is 89 // responsible for holding the returned CommandResult. When the CommandResult object is destroyed, 90 // the child process is killed. 91 // 92 // On the other hand, execute() returns with the child process terminated, either exitCode or signal 93 // is set. 94 // 95 // If the parent process has encountered any errors for system calls, return ExecuteError with 96 // the proper errno set. 97 android::base::Result<CommandResult> execute(std::vector<std::string> argStringVec, 98 const std::function<bool(const CommandResult&)>& end); 99 } // namespace android 100