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/*
* Copyright (C) 2021 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <optional>
#include <ostream>
#include <string>
#include <variant>
#include <vector>
#include <android-base/macros.h>
#include <android-base/result.h>
#include <android-base/unique_fd.h>
/**
* Log a lot more information about host-device binder communication, when debugging issues.
*/
#define SHOULD_LOG_HOST false
#if SHOULD_LOG_HOST
#define LOG_HOST(...) ALOGI(__VA_ARGS__)
#else
#define LOG_HOST(...) ALOGV(__VA_ARGS__) // for type checking
#endif
namespace android {
struct CommandResult {
std::optional<int32_t> exitCode;
std::optional<int32_t> signal;
std::optional<pid_t> pid;
std::string stdoutStr;
std::string stderrStr;
android::base::unique_fd outPipe;
android::base::unique_fd errPipe;
CommandResult() = default;
CommandResult(CommandResult&& other) noexcept { (*this) = std::move(other); }
CommandResult& operator=(CommandResult&& other) noexcept {
std::swap(exitCode, other.exitCode);
std::swap(signal, other.signal);
std::swap(pid, other.pid);
std::swap(stdoutStr, other.stdoutStr);
std::swap(stderrStr, other.stderrStr);
return *this;
}
~CommandResult();
[[nodiscard]] std::string toString() const;
[[nodiscard]] bool stdoutEndsWithNewLine() const {
return !stdoutStr.empty() && stdoutStr.back() == '\n';
}
private:
DISALLOW_COPY_AND_ASSIGN(CommandResult);
};
std::ostream& operator<<(std::ostream& os, const CommandResult& res);
// Execute a command using tokens specified in @a argStringVec.
//
// @a end is a predicate checked periodically when the command emits any output to stdout or
// stderr. When it is evaluated to true, the function returns immediately even though
// the child process has not been terminated. The function also assumes that, after @a end
// is evaluated to true, the child process does not emit any other messages.
// If this is not the case, caller to execute() must handle these I/O in the pipes in the returned
// CommandResult object. Otherwise the child program may hang on I/O.
//
// If @a end is nullptr, it is equivalent to a predicate that always returns false. In this
// case, execute() returns after the child process is terminated.
//
// If @a end is evaluated to true, and execute() returns with the child process running,
// the returned CommandResult has pid, outPipe, and errPipe set. In this case, the caller is
// responsible for holding the returned CommandResult. When the CommandResult object is destroyed,
// the child process is killed.
//
// On the other hand, execute() returns with the child process terminated, either exitCode or signal
// is set.
//
// If the parent process has encountered any errors for system calls, return ExecuteError with
// the proper errno set.
android::base::Result<CommandResult> execute(std::vector<std::string> argStringVec,
const std::function<bool(const CommandResult&)>& end);
} // namespace android
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