240 lines
8.2 KiB
C++
240 lines
8.2 KiB
C++
/*
|
|
* Copyright (C) 2020 Emeric Poupon
|
|
*
|
|
* This file is part of LMS.
|
|
*
|
|
* LMS is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* LMS is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with LMS. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include "ChildProcess.hpp"
|
|
|
|
#include <fcntl.h>
|
|
#include <signal.h>
|
|
#include <sys/types.h>
|
|
#include <sys/wait.h>
|
|
#include <unistd.h>
|
|
|
|
#include <algorithm>
|
|
#include <cerrno>
|
|
#include <cstddef>
|
|
#include <mutex>
|
|
#include <system_error>
|
|
|
|
#include <boost/asio/buffer.hpp>
|
|
#include <boost/asio/read.hpp>
|
|
|
|
#include "core/ILogger.hpp"
|
|
|
|
namespace lms::core
|
|
{
|
|
namespace
|
|
{
|
|
class SystemException : public ChildProcessException
|
|
{
|
|
public:
|
|
SystemException(std::error_code err, const std::string& errMsg)
|
|
: ChildProcessException{ errMsg + ": " + err.message() }
|
|
{
|
|
}
|
|
|
|
SystemException(boost::system::error_code ec, const std::string& errMsg)
|
|
: ChildProcessException{ errMsg + ": " + ec.message() }
|
|
{
|
|
}
|
|
};
|
|
} // namespace
|
|
|
|
ChildProcess::ChildProcess(boost::asio::io_context& ioContext, const std::filesystem::path& path, const Args& args)
|
|
: _ioContext{ ioContext }
|
|
, _childStdout{ _ioContext }
|
|
|
|
{
|
|
// make sure only one thread is executing this part of code
|
|
static std::mutex mutex;
|
|
const std::scoped_lock lock{ mutex };
|
|
|
|
int pipefd[2];
|
|
|
|
// Use 'pipe' instead of 'pipe2', more portable
|
|
if (pipe(pipefd) == -1)
|
|
throw SystemException{ std::error_code{ errno, std::generic_category() }, "pipe failed!" };
|
|
|
|
// Only set O_NONBLOCK on read end - usually programs don't expect stdout to be non-blocking
|
|
if (fcntl(pipefd[0], F_SETFL, O_NONBLOCK) == -1)
|
|
throw SystemException{ std::error_code{ errno, std::generic_category() }, "fcntl failed to set O_NONBLOCK!" };
|
|
|
|
#if defined(__linux__) && defined(F_SETPIPE_SZ)
|
|
for (const int fd : { pipefd[0], pipefd[1] })
|
|
{
|
|
constexpr int targetPipeSize{ 65'536 * 4 };
|
|
int currentPipeSize{ 65'536 }; // common default value
|
|
#if defined(F_GETPIPE_SZ)
|
|
const int pipeSizeRes{ fcntl(fd, F_GETPIPE_SZ) };
|
|
if (pipeSizeRes == -1)
|
|
{
|
|
const int err{ errno };
|
|
LMS_LOG(CHILDPROCESS, DEBUG, "F_GETPIPE_SZ failed: " << (std::error_code{ err, std::generic_category() }.message()));
|
|
}
|
|
else
|
|
{
|
|
currentPipeSize = pipeSizeRes;
|
|
}
|
|
#endif
|
|
if (currentPipeSize < targetPipeSize)
|
|
{
|
|
if (::fcntl(fd, F_SETPIPE_SZ, targetPipeSize) == -1)
|
|
{
|
|
const int err{ errno };
|
|
LMS_LOG(CHILDPROCESS, DEBUG, "F_SETPIPE_SZ failed: " << (std::error_code{ err, std::generic_category() }.message()));
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
const int res{ fork() };
|
|
if (res == -1)
|
|
throw SystemException{ std::error_code{ errno, std::generic_category() }, "fork failed!" };
|
|
|
|
if (res == 0) // CHILD
|
|
{
|
|
// Never close stdin/out/err, most programs expect these to exist;
|
|
// rather connect them to /dev/null if unwanted
|
|
const int nullFd{ open("/dev/null", O_RDWR) };
|
|
// Ignore errors, worst thing is stderr writes to the same fd as lms
|
|
if (nullFd != -1)
|
|
{
|
|
dup2(nullFd, STDIN_FILENO);
|
|
dup2(nullFd, STDERR_FILENO);
|
|
close(nullFd);
|
|
}
|
|
|
|
// Replace stdout with pipe write
|
|
if (dup2(pipefd[1], STDOUT_FILENO) == -1)
|
|
exit(-1);
|
|
// Close pipe: read end not needed, write end was dup2ed
|
|
close(pipefd[0]);
|
|
close(pipefd[1]);
|
|
|
|
std::vector<const char*> execArgs;
|
|
std::transform(std::cbegin(args), std::cend(args), std::back_inserter(execArgs), [](const std::string& arg) { return arg.c_str(); });
|
|
execArgs.push_back(nullptr);
|
|
|
|
execv(path.string().c_str(), (char* const*)&execArgs[0]);
|
|
exit(-1);
|
|
}
|
|
else // PARENT
|
|
{
|
|
close(pipefd[1]);
|
|
{
|
|
boost::system::error_code assignError;
|
|
_childStdout.assign(pipefd[0], assignError);
|
|
if (assignError)
|
|
throw SystemException{ assignError, "assigning read end of pipe to asio stream failed!" };
|
|
}
|
|
_childPID = res;
|
|
}
|
|
}
|
|
|
|
ChildProcess::~ChildProcess()
|
|
{
|
|
LMS_LOG(CHILDPROCESS, DEBUG, "Closing child process...");
|
|
{
|
|
boost::system::error_code closeError;
|
|
_childStdout.close(closeError);
|
|
if (closeError)
|
|
LMS_LOG(CHILDPROCESS, ERROR, "Closed failed: " << closeError.message());
|
|
}
|
|
|
|
if (!_finished)
|
|
kill();
|
|
|
|
wait(true);
|
|
}
|
|
|
|
void ChildProcess::kill()
|
|
{
|
|
// process may already have finished
|
|
LMS_LOG(CHILDPROCESS, DEBUG, "Killing child process...");
|
|
if (::kill(_childPID, SIGKILL) == -1)
|
|
{
|
|
const int err{ errno };
|
|
LMS_LOG(CHILDPROCESS, DEBUG, "Kill failed: " << (std::error_code{ err, std::generic_category() }.message()));
|
|
}
|
|
}
|
|
|
|
bool ChildProcess::wait(bool block)
|
|
{
|
|
assert(!_waited);
|
|
|
|
int wstatus{};
|
|
const pid_t pid{ waitpid(_childPID, &wstatus, block ? 0 : WNOHANG) };
|
|
|
|
if (pid == -1)
|
|
throw SystemException{ std::error_code{ errno, std::generic_category() }, "waitpid failed!" };
|
|
if (pid == 0)
|
|
return false;
|
|
|
|
if (WIFEXITED(wstatus))
|
|
{
|
|
_exitCode = WEXITSTATUS(wstatus);
|
|
LMS_LOG(CHILDPROCESS, DEBUG, "Exit code = " << *_exitCode);
|
|
}
|
|
|
|
_waited = true;
|
|
return true;
|
|
}
|
|
|
|
void ChildProcess::asyncRead(std::byte* data, std::size_t bufferSize, ReadCallback callback)
|
|
{
|
|
assert(!finished());
|
|
|
|
LMS_LOG(CHILDPROCESS, DEBUG, "Async read, bufferSize = " << bufferSize);
|
|
|
|
boost::asio::async_read(_childStdout, boost::asio::buffer(data, bufferSize),
|
|
[this, callback{ std::move(callback) }](const boost::system::error_code& error, std::size_t bytesTransferred) {
|
|
LMS_LOG(CHILDPROCESS, DEBUG, "Async read cb - ec = '" << error.message() << "' (" << error.value() << "), bytesTransferred = " << bytesTransferred);
|
|
|
|
ReadResult readResult{ ReadResult::Success };
|
|
if (error)
|
|
{
|
|
if (error != boost::asio::error::eof)
|
|
{
|
|
// forbidden to read any captured param here as the ChildProcess instance may already have been killed
|
|
return;
|
|
}
|
|
|
|
readResult = ReadResult::EndOfFile;
|
|
_finished = true;
|
|
}
|
|
|
|
callback(readResult, bytesTransferred);
|
|
});
|
|
}
|
|
|
|
std::size_t ChildProcess::readSome(std::byte* data, std::size_t bufferSize)
|
|
{
|
|
boost::system::error_code ec;
|
|
const std::size_t res{ _childStdout.read_some(boost::asio::buffer(data, bufferSize), ec) };
|
|
LMS_LOG(CHILDPROCESS, DEBUG, "read some " << res << " bytes, ec = " << ec.message());
|
|
if (ec)
|
|
_childStdout.close(ec);
|
|
|
|
return res;
|
|
}
|
|
|
|
bool ChildProcess::finished() const
|
|
{
|
|
return _finished;
|
|
}
|
|
} // namespace lms::core
|