/** 
 * @FileName    server_socket.c
 * @Describe    A simple example for creating a listen as a server and simulate generate a sigpipe signal in linux.
 * @Author      vfhky 2016-02-29 08:01 https://typecodes.com/cseries/tcpclosewaitsigpipe.html
 * @Compile     gcc server_socket.c -o server_socket
 */
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <signal.h>

//Whether add a signal handle.
#define SIGNAL_HANDLE 0

void sig_handle( int signal )
{
    printf( "Receive a signal=[%d].\n", signal );
    return;
}

int main( int argc, char **argv )
{
    int server_sockfd;
    int client_sockfd;
    int len;
    int llOpt = 1;
    struct sockaddr_in my_addr;
    struct sockaddr_in remote_addr;
    int sin_size;
    char buf[BUFSIZ];
    memset( &my_addr, 0, sizeof(my_addr) );
    my_addr.sin_family = AF_INET;
    my_addr.sin_addr.s_addr = INADDR_ANY;
    my_addr.sin_port = htons(8000);

    #if SIGNAL_HANDLE
    struct sigaction new_act, old_act;
    new_act.sa_handler = sig_handle;
    new_act.sa_flags = 0;
    sigemptyset( &new_act.sa_mask );
    sigaction( SIGPIPE, &new_act, &old_act );
    sigaction( SIGINT, &new_act, &old_act );    
    #endif

    if( ( server_sockfd = socket( AF_INET, SOCK_STREAM, 0 ) ) < 0 )
    {  
        perror("socket");
        return 1;
    }

    if( setsockopt( server_sockfd, SOL_SOCKET, SO_REUSEADDR, &llOpt, sizeof(llOpt) ) ) {
        close(server_sockfd);
        return errno;
    }

    if( bind( server_sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr) ) < 0 )
    {
        perror( "bind" );
        return 1;
    }

    listen( server_sockfd, 5 );

    sin_size = sizeof( struct sockaddr_in );

    printf( "Server is listening with pid=[%d].\n", getpid() );

    while(1)
    {
        if( ( client_sockfd = accept( server_sockfd, (struct sockaddr *)&remote_addr, &sin_size ) ) < 0 )
        {
            perror( "accept" );
            return 1;
        }
        //Print the ip address and port of client.
        printf( "Accept client[%s:%u].\n", inet_ntoa(remote_addr.sin_addr), ntohs(remote_addr.sin_port) );

        send( client_sockfd, "Auto response from server.", strlen("Auto response from server."), 0 );

        memset( buf, 0x00, BUFSIZ );
        while( ( len = recv( client_sockfd ,buf, BUFSIZ, 0) ) > 0 )
        {
            buf[len]='\0';
            printf( "Message from client=[%s]\n", buf );
        }
        close( client_sockfd );
    }
    close( server_sockfd );
    return 0;
}