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 <functional> 20 #include <optional> 21 #include <ostream> 22 #include <string> 23 #include <variant> 24 #include <vector> 25 26 #include <android-base/macros.h> 27 #include <binder/Common.h> 28 #include <binder/unique_fd.h> 29 #include <utils/Errors.h> 30 31 /** 32 * Log a lot more information about host-device binder communication, when debugging issues. 33 */ 34 #define SHOULD_LOG_HOST false 35 36 #if SHOULD_LOG_HOST 37 #define LOG_HOST(...) ALOGI(__VA_ARGS__) 38 #else 39 #define LOG_HOST(...) ALOGV(__VA_ARGS__) // for type checking 40 #endif 41 42 namespace android { 43 44 struct LIBBINDER_EXPORTED CommandResult { 45 std::optional<int32_t> exitCode; 46 std::optional<int32_t> signal; 47 std::optional<pid_t> pid; 48 std::string stdoutStr; 49 std::string stderrStr; 50 51 binder::unique_fd outPipe; 52 binder::unique_fd errPipe; 53 54 CommandResult() = default; CommandResultCommandResult55 CommandResult(CommandResult&& other) noexcept { (*this) = std::move(other); } 56 CommandResult& operator=(CommandResult&& other) noexcept { 57 std::swap(exitCode, other.exitCode); 58 std::swap(signal, other.signal); 59 std::swap(pid, other.pid); 60 std::swap(stdoutStr, other.stdoutStr); 61 std::swap(stderrStr, other.stderrStr); 62 return *this; 63 } 64 ~CommandResult(); 65 [[nodiscard]] std::string toString() const; 66 stdoutEndsWithNewLineCommandResult67 [[nodiscard]] bool stdoutEndsWithNewLine() const { 68 return !stdoutStr.empty() && stdoutStr.back() == '\n'; 69 } 70 71 private: 72 CommandResult(const CommandResult&) = delete; 73 void operator=(const CommandResult&) = delete; 74 }; 75 76 LIBBINDER_EXPORTED std::ostream& operator<<(std::ostream& os, const CommandResult& res); 77 78 // Execute a command using tokens specified in @a argStringVec. 79 // 80 // @a end is a predicate checked periodically when the command emits any output to stdout or 81 // stderr. When it is evaluated to true, the function returns immediately even though 82 // the child process has not been terminated. The function also assumes that, after @a end 83 // is evaluated to true, the child process does not emit any other messages. 84 // If this is not the case, caller to execute() must handle these I/O in the pipes in the returned 85 // CommandResult object. Otherwise the child program may hang on I/O. 86 // 87 // If @a end is nullptr, it is equivalent to a predicate that always returns false. In this 88 // case, execute() returns after the child process is terminated. 89 // 90 // If @a end is evaluated to true, and execute() returns with the child process running, 91 // the returned CommandResult has pid, outPipe, and errPipe set. In this case, the caller is 92 // responsible for holding the returned CommandResult. When the CommandResult object is destroyed, 93 // the child process is killed. 94 // 95 // On the other hand, execute() returns with the child process terminated, either exitCode or signal 96 // is set. 97 // 98 // If the parent process has encountered any errors for system calls, return ExecuteError with 99 // the proper errno set. 100 LIBBINDER_EXPORTED std::optional<CommandResult> execute( 101 std::vector<std::string> argStringVec, 102 const std::function<bool(const CommandResult&)>& end); 103 } // namespace android 104