fd_utility.cpp

// Copyright (c) 2011 Baidu, Inc.
// 
// 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.

// Author: Ge,Jun (gejun@baidu.com)
// Date: Mon. Nov 7 14:47:36 CST 2011

#include <fcntl.h>                   // fcntl()
#include <netinet/in.h>              // IPPROTO_TCP
#include <sys/types.h>
#include <sys/socket.h>              // setsockopt
#include <netinet/tcp.h>             // TCP_NODELAY

namespace butil {

int make_non_blocking(int fd) {
    const int flags = fcntl(fd, F_GETFL, 0);
    if (flags < 0) {
        return flags;
    }
    if (flags & O_NONBLOCK) {
        return 0;
    }
    return fcntl(fd, F_SETFL, flags | O_NONBLOCK);
}

int make_blocking(int fd) {
    const int flags = fcntl(fd, F_GETFL, 0);
    if (flags < 0) {
        return flags;
    }
    if (flags & O_NONBLOCK) {
        return fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
    }
    return 0;
}

int make_close_on_exec(int fd) {
    return fcntl(fd, F_SETFD, FD_CLOEXEC);
}

int make_no_delay(int socket) {
    int flag = 1;
    return setsockopt(socket, IPPROTO_TCP, TCP_NODELAY, (char*)&flag, sizeof(flag));
}

}  // namespace butil