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/*
* Copyright (c) 2000 - 2014 Samsung Electronics Co., Ltd All Rights Reserved
*
* 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
*/
/*
* @file file-lock.cpp
* @author Krzysztof Jackiewicz (k.jackiewicz@samsung.com)
* @version 1.0
*/
#include "file-lock.h"
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <stdexcept>
#include <string>
#include <sstream>
#include <stringify.h>
#include <dpl/errno_string.h>
namespace CKM {
namespace {
// TODO replace it with custom exception when they are implemented
template <typename... Args>
std::runtime_error io_exception(const Args &... args)
{
return std::runtime_error(Stringify::Merge(args...));
};
} // namespace anonymous
FileLock::FileLock(const char *const file)
{
// Open lock file
m_lockFd = TEMP_FAILURE_RETRY(creat(file, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH));
if (m_lockFd == -1)
throw io_exception("Cannot open lock file. Errno: ", GetErrnoString());
if (-1 == lockf(m_lockFd, F_TLOCK, 0)) {
if (errno == EACCES || errno == EAGAIN)
throw io_exception("Can't acquire lock. Another instance must be running.");
else
throw io_exception("Can't acquire lock. Errno: ", GetErrnoString());
}
std::string pid = std::to_string(getpid());
ssize_t written = TEMP_FAILURE_RETRY(write(m_lockFd, pid.c_str(), pid.size()));
if (-1 == written || static_cast<ssize_t>(pid.size()) > written)
throw io_exception("Can't write file lock. Errno: ", GetErrnoString());
int ret = fsync(m_lockFd);
if (-1 == ret)
throw io_exception("Fsync failed. Errno: ", GetErrnoString());
}
FileLock::~FileLock()
{
// this will also release the lock
close(m_lockFd);
}
} /* namespace CKM */
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