Linux下网络编程-基于多任务的简易客户端

//沿用之前的代码修改即可
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <sys/wait.h>
#include <arpa/inet.h>
#include <sys/socket.h>#define BUF_SIZE 30
void error_handling(const char *message);
void read_childproc(int sig);int main(int argc, char *argv[])
{int serv_sock, clnt_sock;struct sockaddr_in serv_adr, clnt_adr;pid_t pid;struct sigaction act;socklen_t adr_sz;int str_len, state;char buf[BUF_SIZE];if(argc!=2) {printf("Usage : %s <port>\n", argv[0]);exit(1);}//为防止产生僵尸进程act.sa_handler=read_childproc;sigemptyset(&act.sa_mask);act.sa_flags=0;state=sigaction(SIGCHLD, &act, 0);serv_sock=socket(PF_INET, SOCK_STREAM, 0);memset(&serv_adr, 0, sizeof(serv_adr));serv_adr.sin_family=AF_INET;serv_adr.sin_addr.s_addr=htonl(INADDR_ANY);serv_adr.sin_port=htons(atoi(argv[1]));if(bind(serv_sock, (struct sockaddr*) &serv_adr, sizeof(serv_adr))==-1)error_handling("bind() error");if(listen(serv_sock, 5)==-1)error_handling("listen() error");while(1){adr_sz=sizeof(clnt_adr);clnt_sock=accept(serv_sock, (struct sockaddr*)&clnt_adr, &adr_sz);if(clnt_sock==-1)continue;elseputs("new client connected...");//父子进程分别带有1个accept生成的套接字（受理客户端连接请求时创建的）文//件描述符pid=fork();if(pid==-1){close(clnt_sock);continue;}if(pid==0){//子进程运行的区域close(serv_sock);while((str_len=read(clnt_sock, buf, BUF_SIZE))!=0)write(clnt_sock, buf, str_len);close(clnt_sock);puts("client disconnected...");return 0;}elseclose(clnt_sock);}///通过accept函数创建的套接字文件描述符已复制给子进程，因此服务//器端需要销毁自己拥有的文件描述符close(serv_sock);return 0;
}void read_childproc(int sig)
{pid_t pid;int status;pid=waitpid(-1, &status, WNOHANG);printf("removed proc id: %d \n", pid);
}void error_handling(const char *message)
{fputs(message, stderr);fputc('\n', stderr);exit(1);
}