Linux C 网络编程之路——完善tcp_server ，依然是点对点通信

common.h

#ifndef __COMMON__H__
#define __COMMON__H__

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <signal.h>
#define LOG_SOFT(fmt,...) printf("%s,%d:" fmt,__FUNCTION__,__LINE__,##__VA_ARGS__)

#define SERVER_PORT 8600

#define LOG_SOFT(fmt,...) printf("%s,%d:" fmt,__FUNCTION__,__LINE__,##__VA_ARGS__)
#define LOG_SOFT_ERRNO(fmt,...) printf("errno:%d,%s,%s,%d:" fmt,errno,strerror(errno),__FUNCTION__,__LINE__,##__VA_ARGS__)


#define BUFFER_SIZE 1024


#endif

tcp_server.c

#include "common.h"

void signal_handle_SIGINT(int signal)
{
    LOG_SOFT("signal = %d\n",signal);
}

static void handle_sigpipe(void)
{
    struct sigaction sa;
    sa.sa_handler = SIG_IGN;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = 0;
    sigaction(SIGPIPE,&sa,NULL);
}


int main()
{
    //避免自动重启被中断的系统调用：SA_RESTART标志
    struct sigaction sa_in;
    sa_in.sa_handler = signal_handle_SIGINT;
    sigemptyset(&sa_in.sa_mask);
    sa_in.sa_flags = 0;
    sigaction(SIGINT,&sa_in,NULL);

    handle_sigpipe();
    int client_fd = -1;
    int socket_fd = socket(AF_INET,SOCK_STREAM | SOCK_CLOEXEC ,0);
    char buf[BUFFER_SIZE] = {0};
    if(socket_fd < 0)
    {
        LOG_SOFT_ERRNO("socket faild\n");
        goto on_errno;
    }
    int value = 1;
    //SO_REUSEADDR: 当服务进程崩溃重启或者主动重启时，会进入time_wait，如果不使用该选项，会导致服务无法启动
    if(setsockopt(socket_fd,SOL_SOCKET,SO_REUSEADDR,&value,sizeof(value)) < 0)
    {
        LOG_SOFT_ERRNO("setsockopt faild\n");
        goto on_errno;
    }
    struct sockaddr_in server_addr;
    memset(&server_addr,0,sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(SERVER_PORT);
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);

    int addr_len = sizeof(server_addr);
    int ret = bind(socket_fd,(const struct sockaddr*)&server_addr,addr_len);
    if(ret < 0)
    {
        LOG_SOFT_ERRNO("bind faild\n");
        goto on_errno;
    }

    ret = listen(socket_fd,5);
    if(ret < 0)
    {
        LOG_SOFT_ERRNO("listen faild\n");
        goto on_errno;
    }

    struct sockaddr_in client_addr;
    while (1)
    {
        client_fd = accept(socket_fd, (struct sockaddr *)&client_addr, (socklen_t *)&addr_len);
        if (client_fd <= 0)
        {   //暂时无连接，继续等待
            if (errno == EAGAIN || errno == EWOULDBLOCK)
            {
                LOG_SOFT("accept: nopeding connections now, break loop.\n");
                continue;;
            }
            else if (errno == EINTR)
            {
                // 被系统信号中断
                LOG_SOFT("accept:EINTR.\n");
                continue;
            }
            else if (errno == ECONNABORTED)
            {
                // 丢弃该链接
                LOG_SOFT("acceot:connection aborted by client,continue.\n");
                continue;
            }
            else
            {
                LOG_SOFT_ERRNO("accept fatal error,exit...\n");
                goto on_errno;
            }
            
        }
        break;
    }

    
    

    while (1)
    {
        int read_len = read(client_fd, buf, sizeof(buf));
        if (read_len > 0)
        {
            LOG_SOFT("recv data %s\n", buf);
            int offset = 0;
            
            do{
                int w_ret = write(client_fd, buf+offset, read_len - offset);
                if(w_ret < 0){
                    //错误处理
                    if(errno == EINTR)
                    {
                        LOG_SOFT("write EINTR\n");
                        continue;
                    }else if(errno == EAGAIN || errno == EWOULDBLOCK)
                    {
                        LOG_SOFT("write EAGAIN or EWOULDBLOCK\n");
                        continue;
                    }else{
                        goto on_errno;
                    }
                }else {

                    offset += w_ret;
                    if(offset == read_len){
                        break;//发送完毕了
                    }
                }
            }while(1);
            
            // break;
        }
        else if (read_len < 0)
        {
            LOG_SOFT("recv errno:%d,%s", errno, strerror(errno));
            if(errno == EINTR)
            {
                LOG_SOFT("read EINTR\n");
                continue;
            }else{
                goto on_errno;
            }
            // break;
        }
        else
        {
            LOG_SOFT("ret == 0,fd:%d\n", socket_fd);
            break;
           
        }
    }

    close(socket_fd);
    close(client_fd);


    return 0;

    on_errno:
        close(socket_fd);
        if(client_fd != -1)
        {
            close(client_fd);
        }
       
        return -1;
}