/*************************************************************************
  > File Name: ipc_udp_server.cpp
  > Author: TianLun Song
  > Mail: songtianlun@frytea.com
  > Blog: https://blog.frytea.com
  > Created Time: Wed 13 Jan 2021 09:53:06 AM CST
 ************************************************************************/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <memory.h>
#include <unistd.h>
#include <stdio.h>
#include <iostream>

using namespace std;
const char* server_file = "/tmp/criu/ipc_udp_server.sock";

int main(int argc,char** argv)
{
    int socket_fd = socket(AF_UNIX,SOCK_DGRAM,0);
    if (socket_fd < 0)
    {
        perror("socket");
        return -1;
    }
    struct sockaddr_un addr;
    memset(&addr,0,sizeof(addr));
    addr.sun_family = AF_UNIX;
    strcpy(addr.sun_path,server_file);
    if (access(addr.sun_path,0) != -1)
    {
        remove(addr.sun_path);
    }
    if (bind(socket_fd,(sockaddr*)&addr,sizeof(addr)) < 0)
    {
        perror("bind");
        return -1;
    }
    struct sockaddr_un clientaddr;
    socklen_t addrlen = sizeof(clientaddr);
    char msg_buf[1024];
    while (1)
    {
        // printf("socket file is ok: %d", access(addr.sun_path, F_OK));
        // if(access(addr.sun_path, F_OK) !=0 )
        // {
        //     bind(socket(AF_UNIX,SOCK_DGRAM,0),(sockaddr*)&addr,sizeof(addr));
        //     printf("socket file is missing, rebind.\n");
        // }
        memset(msg_buf,'\0',1024);
        int rsize = recvfrom(socket_fd,msg_buf,sizeof(msg_buf),0,(sockaddr*)&clientaddr,&addrlen);
        if (rsize < 0)
        {
            perror("server recv error!");
            continue;
        }
        cout << "I'm Unix socket(UDP) server, recv a msg: " << msg_buf  << " from: " << clientaddr.sun_path << endl;
        strcpy(msg_buf, "OK,I got it!");
        int ssize = sendto(socket_fd, msg_buf, sizeof msg_buf,0,(sockaddr*)&clientaddr,addrlen);
        if (ssize < 0)
        {
            perror("server send error!");
            continue;
        }
        sleep(1);
    }
    if (close(socket_fd) < 0)
    {
        perror("close socket");
        return -1;
    }
    return 0;
}