2 * Copyright (C) 2018 Cisco Inc.
4 * This program is free software: you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License, version 2,
6 * as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License
14 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 // @author Changxue Deng <chadeng@cisco.com>
29 int acquire_writer_lock(const std::string &lock_file_path)
31 int fd = open(lock_file_path.c_str(), O_WRONLY | O_CREAT,
32 S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
35 std::cerr << "failed to open lock file " << lock_file_path
36 << " errno: " << errno << std::endl;
40 struct flock writer_lock;
41 writer_lock.l_type = F_WRLCK;
42 writer_lock.l_start = 0;
43 writer_lock.l_whence = SEEK_SET;
44 writer_lock.l_len = 0;
45 if(fcntl(fd, F_SETLK, &writer_lock) != 0)
47 std::cerr << "failed to lock file " << lock_file_path
48 << " errno: " << errno << std::endl;
56 void release_writer_lock(int &fd)