多进程回声服务器
服务器搭建思路
- 处理僵尸进程
- 生成服务端
- 循环接收客服端连接并开辟新进程处理新连接
以下是服务器实例：
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/socket.h>
#include<netinet/tcp.h>
#include<wait.h>
#include<signal.h>
#include<bits/sigaction.h>//子进程退出信号回调函数
void ChildExitHandle()
{//使用waitpid()函数int status;pid_t pid = waitpid(-1,&status,WNOHANG);//监控任意子进程、状态信息、非阻塞if (WIFEXITED(status)){printf("Child process exited.\n");printf("The child process's id is %d\n",WEXITSTATUS(status));}}//错误处理
void error_handing(char *message)
{fputs(message,stderr);fputc('\n',stderr);exit(1);
}int main(int argc, char const *argv[])
{//步骤1：处理僵尸进程 -> 使用sigaction()函数struct sigaction sig_cfg;sig_cfg.sa_handler = ChildExitHandle;sigaction(SIGCLD,&sig_cfg,NULL);//步骤2.1：生成服务端socketint server_sock;server_sock = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);if (server_sock == -1){error_handing("socket() error");}//步骤2.2：绑定监听端口struct sockaddr_in server_addr;memset(&server_addr,0,sizeof(server_addr));server_addr.sin_family = AF_INET;server_addr.sin_addr.s_addr = htonl(INADDR_ANY);server_addr.sin_port = htons(atoi("3333"));if (bind(server_sock,(struct sockaddr *)&server_addr,sizeof(server_addr)) == -1){error_handing("bind() error");}//步骤2.3：开启端口监听if (listen(server_sock,5) == -1){error_handing("listen() error");}//步骤3：循环接收客服端连接并开辟新进程处理新连接while (1){//步骤3.1：接受连接int accept_sock;struct sockaddr accept_addr;socklen_t len = sizeof(accept_addr);accept_sock = accept(server_sock,&accept_addr,&len);//第二个参数存储接入的客户端的地址信息if (accept_sock == -1){//error_handing("accept() error");continue;}else{printf("New client connected...\n");}//步骤3.2：开辟新进程与客户端交互pid_t pid = fork();if (pid == 0)//子进程{//子进程同时也复制了父进程的server_sock，要关闭close(server_sock);//步骤3.3：开始交互const int message_size = 10;char message[message_size];int read_len = 0;while((read_len=read(accept_sock, message, message_size))!=0)write(accept_sock, message, read_len);//步骤3.3：交互完毕，关闭连接close(accept_sock);//步骤3.4：子进程退出exit(2);}else//父进程{//父进程同时也包含了子进程的accept_sock，要关闭close(accept_sock);}}close(server_sock);return 0;
}
客户端实例：采用分割I/O的方法，将输入和出输出分割，简化逻辑
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h> #define BUF_SIZE 30
void error_handling(char *message);
void read_routline(int sock, char *buf);
void write_routline(int sock, char *buf);int main(int argc, char *argv[])
{int sock; pid_t pid;struct sockaddr_in serv_addr;char message[BUF_SIZE]; int str_len,i; if (argc != 3){printf("Usage : %s <IP> <port>\n", argv[0]);exit(1); }//步骤1：创建套接字sock = socket(PF_INET, SOCK_STREAM, 0);if (sock == -1) error_handling("socket() error"); //步骤2：连接端口memset(&serv_addr, 0, sizeof(serv_addr));serv_addr.sin_family = AF_INET; // 地址族设置为IPv4serv_addr.sin_addr.s_addr = inet_addr(argv[1]); // 设置服务器IP地址serv_addr.sin_port = htons(atoi(argv[2])); // 设置服务器端口号// 发送连接请求if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) == -1)error_handling("connect() error"); else{printf("Connected ok\n");}//步骤3：进行通讯pid=fork();if(pid==0){write_routline(sock,message);}else{read_routline(sock,message);close(sock);return 0;}}void error_handling(char* message){fputs(message, stderr); fputc('\n', stderr); exit(1);
}void write_routline(int sock, char *buf){while(1){fgets(buf, BUF_SIZE, stdin);if(!strcmp(buf,"q\n")||!strcmp(buf,"Q\n")){shutdown(sock, SHUT_WR);return;}write(sock, buf, strlen(buf));}
}void read_routline(int sock, char *buf){while(1){int str_len=read(sock, buf, BUF_SIZE);if(str_len==0){return;}buf[str_len]=0;printf("Message from server:%s", buf);}
}使用客户端 ：./client “服务端ip” “端口”