Linux网络多进程并发服务器和多线程并发服务器

多进程
还是以大小写转换为例子

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include "wrap.h"
#include <ctype.h>
#include <signal.h>
#include <sys/wait.h>

#define SERV_PORT 9527

void catch_child(int signum)//信号，用来回收子进程
{
    while((waitpid(0,NULL,WNOHANG)) > 0);
    return;
}

int main(int argc,char* argv[])
{
    int lfd,cfd;
    int ret,i;
    char buf[BUFSIZ],client_IP[1024];
    pid_t pid;
    struct sockaddr_in serv_addr,clit_addr;
    socklen_t clit_addr_len;
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(SERV_PORT);
    serv_addr.sin_addr.s_addr = htonl (INADDR_ANY);
    lfd = Socket(AF_INET,SOCK_STREAM,0);
    Bind(lfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr));
    Listen(lfd,128);
    
    clit_addr_len = sizeof(clit_addr);
    while(1)
    {
        cfd =  Accept(lfd,(struct sockaddr*)&clit_addr,&clit_addr_len);
        pid = fork();//创建子进程
        if(pid < 0)
        {
            perr_exit("fork error");
        }
        else if(pid == 0)
        {
            printf("client ip:%s port%d\n",
                inet_ntop(AF_INET, &clit_addr.sin_addr.s_addr, client_IP, sizeof(client_IP)),
                ntohs(clit_addr.sin_port));//打印客户端网络信息
            close(lfd);
            break;
        }
        else
        {
        	//父进程调用信号回收子进程
            struct sigaction act;
            act.sa_handler = catch_child;
            sigemptyset(&act.sa_mask);
            act.sa_flags = 0;
            
            ret = sigaction(SIGCHLD,&act,NULL);
            if(ret != 0)
            {
                perr_exit("signal error");
            }
            close(cfd);
            continue;
        }
    }
    
    if(pid == 0)//大小写转换
    {
        for(;;)
        {
            
            ret = read(cfd,buf,sizeof(buf));
            if(ret == 0)
            {
                close(cfd);
                exit(1);
            }
             for(i = 0;i < ret;i++)
            {
                 buf[i] = toupper(buf[i]);
            }       
            write(cfd,buf,ret);
    
            write(STDOUT_FILENO,buf,ret);
        }
    }
    return 0;
}

多线程

#include <stdio.h>
#include <string.h>
#include <arpa/inet.h>
#include <pthread.h>
#include <ctype.h>
#include <unistd.h>
#include <fcntl.h>

#include "wrap.h"

#define MAXLINE 8192
#define SERV_PORT 8000

struct s_info {                     //定义一个结构体, 将地址结构跟cfd捆绑
    struct sockaddr_in cliaddr;
    int connfd;
};

void *do_work(void *arg)
{
    int n,i;
    struct s_info *ts = (struct s_info*)arg;
    char buf[MAXLINE];
    char str[INET_ADDRSTRLEN];      //#define INET_ADDRSTRLEN 16  可用"[+d"查看

    while (1) {
        n = Read(ts->connfd, buf, MAXLINE);                     //读客户端
        if (n == 0) {
            printf("the client %d closed...\n", ts->connfd);
            break;                                              //跳出循环,关闭cfd
        }
        printf("received from %s at PORT %d\n",
                inet_ntop(AF_INET, &(*ts).cliaddr.sin_addr, str, sizeof(str)),
                ntohs((*ts).cliaddr.sin_port));                 //打印客户端信息(IP/PORT)

        for (i = 0; i < n; i++) 
            buf[i] = toupper(buf[i]);                           //小写-->大写

        Write(STDOUT_FILENO, buf, n);                           //写出至屏幕
        Write(ts->connfd, buf, n);                              //回写给客户端
    }
    Close(ts->connfd);

    return (void *)0;
}

int main(void)
{
    struct sockaddr_in servaddr, cliaddr;
    socklen_t cliaddr_len;
    int listenfd, connfd;
    pthread_t tid;

    struct s_info ts[256];      //创建结构体数组.
    int i = 0;

    listenfd = Socket(AF_INET, SOCK_STREAM, 0);                     //创建一个socket, 得到lfd

    bzero(&servaddr, sizeof(servaddr));                             //地址结构清零
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);                               //指定本地任意IP
    servaddr.sin_port = htons(SERV_PORT);                                       //指定端口号 

    Bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr));             //绑定

    Listen(listenfd, 128);                                                      //设置同一时刻链接服务器上限数

    printf("Accepting client connect ...\n");

    while (1) {
        cliaddr_len = sizeof(cliaddr);
        connfd = Accept(listenfd, (struct sockaddr *)&cliaddr, &cliaddr_len);   //阻塞监听客户端链接请求
        ts[i].cliaddr = cliaddr;
        ts[i].connfd = connfd;

        pthread_create(&tid, NULL, do_work, (void*)&ts[i]);
        pthread_detach(tid);                                                    //子线程分离,防止僵线程产生.
        i++;
    }

    return 0;
}