有没有做吉祥物的网站,公众号开发是不是网站开发,电脑网络服务器在哪里,会员卡管理系统代码转载#xff1a;http://blog.csdn.net/li_wen01/article/details/52685844 前面已讲过使用一个进程实现服务端和客户端P2P通信的实例#xff0c;但是它只能同时处理一个客户端的连接。如果要实现并发处理多个客户端的连接并且实现P2P通信#xff0c;可以使用多进程来处理。相…转载http://blog.csdn.net/li_wen01/article/details/52685844 前面已讲过使用一个进程实现服务端和客户端P2P通信的实例但是它只能同时处理一个客户端的连接。如果要实现并发处理多个客户端的连接并且实现P2P通信可以使用多进程来处理。相比与多线程来说多进程耗费的系统资源是比较多的后续会介绍使用线程池实现简单的数据收发。 使用多进程并发处理多个client请求以及实现P2P通信父进程专门监听端口每监听到一个连接就创建一个子进程处理这个客户端于此同时在子进程中创建一个孙子进程来处理数据的读取在子进程实现数据的发送。如果客户端断开连接recv函数会返回参数0recv函数所在进程发送信号给send函数所在进程然后退出recv进程send函数所在进程接收到信号SIGUSR1就退出该进程。在多进程中子进程退出时会产生僵尸进程僵尸进程的处理有多种方法最简单的就是直接忽视SIGCHLD信号。 下面直接上代码 #includestdio.h
#includesys/types.h
#includesys/socket.h
#includeunistd.h
#includestdlib.h
#includeerrno.h
#includearpa/inet.h
#includenetinet/in.h
#includestring.h
#includesignal.h#define MAXLINE 256
#define PORT 6666/*进程退出函数*/
void process_out(int signo)
{exit(EXIT_SUCCESS);
}/*socket write 函数*/
void write_func(int pid, int fd)
{char* write I am server;printf(write id %d\n,pid);signal(SIGUSR1,process_out); /* 注册信号SIGUSR1该信号由read 进程发送过来。*/while(1){sleep(1);send(fd,write,strlen(write)1,0);}
}/*socket read 函数*/
void read_func(int pid, int fd)
{char readbuff[MAXLINE];int n 0;printf(read id %d \n,pid);memset(readbuff,0,sizeof(readbuff));while(1){n recv(fd, readbuff, MAXLINE, 0); /*recv 在这里是阻塞运行*/if(n 0) /*客户端有数据发送过来*/{printf(server recv data: %s \n,readbuff);}else if(n 0) /*客户端断开了连接*/{break;}};kill(pid, SIGUSR1); /*发送信号SIGUSR1 到write进程*/exit(EXIT_SUCCESS); /*进程退出*/
}int main(void)
{int listenfd,connetfd;int on 1;int addrlen 0;pid_t pid, pid_child, pid_send;struct sockaddr_in server_addr;struct sockaddr_in client_addr;if ((listenfd socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) 0){printf(create socket err \n);}/*设置服务端地址*/addrlen sizeof(struct sockaddr_in);memset(server_addr, 0, addrlen);server_addr.sin_family AF_INET; /*AF_INET表示 IPv4 Intern 协议*/server_addr.sin_addr.s_addr htonl(INADDR_ANY); /*INADDR_ANY 可以监听任意IP */server_addr.sin_port htons(PORT); /*设置端口*//*对套接字进行设置*/if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, on, sizeof(on)) 0) {printf(bind socket error: %s(errno: %d)\n,strerror(errno),errno);exit(0);}/*绑定地址结构到套接字描述符*/if( bind(listenfd, (struct sockaddr*)server_addr, sizeof(server_addr)) -1){printf(bind socket error: %s(errno: %d)\n,strerror(errno),errno);exit(0);}/*设置监听队列这里设置为10表示可以同时处理10个客户端的连接*/if( listen(listenfd, 10) -1){printf(listen socket error: %s(errno: %d)\n,strerror(errno),errno);exit(0);}printf(wait client accpt \n);while(1){/*接收客户端的连接这里会阻塞直到有客户端连接*/if( (connetfd accept(listenfd, (struct sockaddr*)client_addr, addrlen)) -1){printf(accept socket error: %s(errno: %d),strerror(errno),errno);continue;}signal(SIGCHLD, SIG_IGN); /*忽略SIGCHLD避免僵尸进程*/pid fork();if(pid -1){printf(fork err \n);}if(pid 0) /* 子进程*/{pid_child fork(); if(pid_child 0) /*孙子进程*/{pid_send getpid(); /*获取孙子进程ID*/read_func(pid_send, connetfd);}else{pid_send getpid(); /* 获取子进程ID*/write_func(pid_send,connetfd);}}}
} 测试程序这里不再实现将上面代码在PC机上编译运行在手机端使用网络助手工具直接连接PC机的6666端口可以看到如下运行结果 rootubuntu:/home/share/Socket/process# ./process_server
wait client accpt
write id 3883
read id 3884
server recv data: I am client 1
server recv data: I am client 1
server recv data: I am client 1
server recv data: I am client 1
write id 3885
read id 3886
server recv data: I am client 1
server recv data: I am client 2
server recv data: I am client 1
server recv data: I am client 2
server recv data: I am client 1
write id 3887
read id 3888
server recv data: I am client 2
server recv data: I am client 1
server recv data: I am client 2
server recv data: I am client 1
server recv data: I am client 2
server recv data: I am client 1
server recv data: I am client 1
server recv data: I am client 1
^C
rootubuntu:/home/share/Socket/process# 先连接三个客户端然后再断开连接客户端收到的数据不再贴出。于此同时我们使用PS查看进程状态 rootubuntu:/home/share# ps aux |grep process_server
root 3882 0.0 0.0 4164 348 pts/0 S 22:38 0:00 ./process_server
root 3883 0.0 0.0 4164 88 pts/0 S 22:38 0:00 ./process_server
root 3884 0.0 0.0 4164 88 pts/0 S 22:38 0:00 ./process_server
root 3885 0.0 0.0 4164 88 pts/0 S 22:38 0:00 ./process_server
root 3886 0.0 0.0 4164 88 pts/0 S 22:38 0:00 ./process_server
root 3887 0.0 0.0 4164 88 pts/0 S 22:38 0:00 ./process_server
root 3888 0.0 0.0 4164 88 pts/0 S 22:38 0:00 ./process_server
root 3890 0.0 0.0 13588 940 pts/2 S 22:38 0:00 grep --colorauto process_server
rootubuntu:/home/share# ps aux |grep process_server
root 3882 0.0 0.0 4164 348 pts/0 S 22:38 0:00 ./process_server
root 3883 0.0 0.0 4164 88 pts/0 S 22:38 0:00 ./process_server
root 3884 0.0 0.0 4164 88 pts/0 S 22:38 0:00 ./process_server
root 3885 0.0 0.0 4164 88 pts/0 S 22:38 0:00 ./process_server
root 3886 0.0 0.0 4164 88 pts/0 S 22:38 0:00 ./process_server
root 3894 0.0 0.0 13588 940 pts/2 S 22:38 0:00 grep --colorauto process_server
rootubuntu:/home/share# ps aux |grep process_server
root 3882 0.0 0.0 4164 348 pts/0 S 22:38 0:00 ./process_server
root 3883 0.0 0.0 4164 88 pts/0 S 22:38 0:00 ./process_server
root 3884 0.0 0.0 4164 88 pts/0 S 22:38 0:00 ./process_server
root 3896 0.0 0.0 13588 940 pts/2 S 22:39 0:00 grep --colorauto process_server
rootubuntu:/home/share# ps aux |grep process_server
root 3882 0.0 0.0 4164 348 pts/0 S 22:38 0:00 ./process_server
root 3898 0.0 0.0 13588 944 pts/2 S 22:39 0:00 grep --colorauto process_server
rootubuntu:/home/share# 可以看到并未产生僵尸进程但是如果把上面程序的signal(SIGCHLD, SIG_IGN);去掉我们就可以看到产生了僵尸进程。 rootubuntu:/home/ysj000# ps aux |grep process_server
root 3812 0.0 0.0 4164 352 pts/0 S 22:24 0:00 ./process_server
root 3814 0.0 0.0 4164 92 pts/0 S 22:25 0:00 ./process_server
root 3815 0.0 0.0 4164 92 pts/0 S 22:25 0:00 ./process_server
root 3816 0.0 0.0 4164 92 pts/0 S 22:25 0:00 ./process_server
root 3817 0.0 0.0 4164 92 pts/0 S 22:25 0:00 ./process_server
root 3819 0.0 0.0 13588 944 pts/2 S 22:25 0:00 grep --colorauto process_server
rootubuntu:/home/ysj000# ps aux |grep process_server
root 3812 0.0 0.0 4164 352 pts/0 S 22:24 0:00 ./process_server
root 3814 0.0 0.0 4164 92 pts/0 S 22:25 0:00 ./process_server
root 3815 0.0 0.0 4164 92 pts/0 S 22:25 0:00 ./process_server
root 3816 0.0 0.0 0 0 pts/0 Z 22:25 0:00 [process_server] defunct
root 3821 0.0 0.0 13588 944 pts/2 S 22:25 0:00 grep --colorauto process_server
rootubuntu:/home/ysj000# ps aux |grep process_server
root 3812 0.0 0.0 4164 352 pts/0 S 22:24 0:00 ./process_server
root 3814 0.0 0.0 0 0 pts/0 Z 22:25 0:00 [process_server] defunct
root 3816 0.0 0.0 0 0 pts/0 Z 22:25 0:00 [process_server] defunct
root 3823 0.0 0.0 13588 944 pts/2 S 22:26 0:00 grep --colorauto process_server
rootubuntu:/home/ysj000# ps aux |grep process_server
root 3812 0.0 0.0 4164 352 pts/0 S 22:24 0:00 ./process_server
root 3814 0.0 0.0 0 0 pts/0 Z 22:25 0:00 [process_server] defunct
root 3816 0.0 0.0 0 0 pts/0 Z 22:25 0:00 [process_server] defunct
root 3824 0.0 0.0 4164 92 pts/0 S 22:26 0:00 ./process_server
root 3825 0.0 0.0 4164 92 pts/0 S 22:26 0:00 ./process_server
root 3827 0.0 0.0 13588 944 pts/2 S 22:26 0:00 grep --colorauto process_server
rootubuntu:/home/ysj000# ps aux |grep process_server
root 3812 0.0 0.0 4164 352 pts/0 S 22:24 0:00 ./process_server
root 3814 0.0 0.0 0 0 pts/0 Z 22:25 0:00 [process_server] defunct
root 3816 0.0 0.0 0 0 pts/0 Z 22:25 0:00 [process_server] defunct
root 3824 0.0 0.0 4164 92 pts/0 S 22:26 0:00 ./process_server
root 3825 0.0 0.0 4164 92 pts/0 S 22:26 0:00 ./process_server
root 3830 0.0 0.0 4164 92 pts/0 S 22:27 0:00 ./process_server
root 3831 0.0 0.0 4164 92 pts/0 S 22:27 0:00 ./process_server
root 3833 0.0 0.0 13588 940 pts/2 S 22:27 0:00 grep --colorauto process_server
rootubuntu:/home/ysj000# ps aux |grep process_server
root 3812 0.0 0.0 4164 352 pts/0 S 22:24 0:00 ./process_server
root 3814 0.0 0.0 0 0 pts/0 Z 22:25 0:00 [process_server] defunct
root 3816 0.0 0.0 0 0 pts/0 Z 22:25 0:00 [process_server] defunct
root 3824 0.0 0.0 4164 92 pts/0 S 22:26 0:00 ./process_server
root 3825 0.0 0.0 4164 92 pts/0 S 22:26 0:00 ./process_server
root 3830 0.0 0.0 0 0 pts/0 Z 22:27 0:00 [process_server] defunct
root 3835 0.0 0.0 13588 944 pts/2 S 22:27 0:00 grep --colorauto process_server
rootubuntu:/home/ysj000# ps aux |grep process_server
root 3812 0.0 0.0 4164 352 pts/0 S 22:24 0:00 ./process_server
root 3814 0.0 0.0 0 0 pts/0 Z 22:25 0:00 [process_server] defunct
root 3816 0.0 0.0 0 0 pts/0 Z 22:25 0:00 [process_server] defunct
root 3824 0.0 0.0 0 0 pts/0 Z 22:26 0:00 [process_server] defunct
root 3830 0.0 0.0 0 0 pts/0 Z 22:27 0:00 [process_server] defunct
root 3839 0.0 0.0 13588 944 pts/2 S 22:27 0:00 grep --colorauto process_server注意1在上面的代码中我们直接忽视了SIGCHLD 信号来避免产生僵尸进程在linux系统中是可以的但是在其他的一些系统不一定都可以。另外直接忽视SIGCHLD信号会造成一些其他的影响会影响system函数的正常使用。system里面会将sigchld设置为阻塞因为system里面会调用fork然后执行命令最后通过waitpid等待子进程的返回不将sigchld设置为阻塞有可能信号被别人处理掉system无法获得到信号就会报错错误号echldno child processes这就是因为信号被别人处理了其实命令是运行成功的。而忽略sigchld信号就会导致这一问题。所以正常使用的时候需要多加注意可以使用wait 或waitpid 来避免僵尸进程如下 void sig_chld(int signo)
{pid_t pid;int stat;while ((pid waitpid(-1,stat,WNOHANG))0){ //printf(child %d terminated \n,pid);}return ;
}信号注册 signal(SIGCHLD, sig_chld); 注意2如果我们不主动收发数据也想检测到TCP连接的对方已经退出或是崩溃我们可以使用套接字选项SO_KEEPALIVE来实现。
