//仅供自己记住代码基础
/*
readline 实现，遇到\n 就算作是一条消息，可以解决粘包问题（遇到\r\n,在包尾，ftp协议就是这么做的）
*/
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#define ERR_EXIT(m)do{perror(m);exit(EXIT_FAILURE);}while(0)
ssize_t readn(int fd, void *buf, size_t count)
{
size_t nleft = count;//剩余的字节数
size_t nread;//接收的字节数
char * bufp = (char *)buf;
while(nleft > 0)
{
if((nread = read(fd,bufp,nleft)) < 0)
{
if(errno == EINTR)//信号中断
continue;
return -1;
}
else if(nread == 0) //客户端关闭了
{
return count - nleft;
}
bufp += nread;
nleft -=nread;
}
return count;
}
ssize_t writen(int fd, const void *buf, size_t count)
{
size_t nleft = count;//剩余的字节数
size_t nwritten;//接收的字节数
char * bufp = (char *)buf;
while(nleft > 0)
{
if((nwritten = write(fd,bufp,nleft)) < 0)
{
if(errno == EINTR)//信号中断
continue;
return -1;
}
else if(nwritten == 0) //客户端关闭了
{
continue;
}
bufp += nwritten;
nleft -=nwritten;
}
return count;
}
//MSG_PEEK 只是从缓存区接收到buf,但是未清除掉套接口缓存区数据
ssize_t recv_peek(int sockfd, void *buf, size_t len)
{
while(1)
{
int ret = recv(sockfd,buf,len,MSG_PEEK);
if(ret == -1 && errno == EINTR)
{
continue;
}
return ret;
}
}
ssize_t readline(int sockfd,void *buf,size_t maxline)
{
int ret;
int nread;//接收到的字节数
char * bufp = buf;
int nleft = maxline;
while(1)
{
ret = recv_peek(sockfd,bufp,nleft);
if(ret <0)
return ret;
else if(ret == 0)
return ret;
nread = ret;
int i;
for(i = 0;i<nread;i++)
{
if(bufp[i] == '\n')
{
ret = readn(sockfd,bufp,i+1);
if(ret != i+1)
{
exit(EXIT_FAILURE);
}
return ret;
}
}
if(nread > nleft)
{
exit(EXIT_FAILURE);
}
nleft -= nread;
ret = readn(sockfd,bufp,nread);
if(ret != nread)
{
exit(EXIT_FAILURE);
}
bufp += nread; //放在后面
}
return -1;
}
//多个客户端可以连接，将accept弄作一个进程，读取发送数据是一个进程
void do_service(int conn)
{
char recvbuf[1024];
while(1)
{
memset(&recvbuf,0,sizeof(recvbuf));
int ret = readline(conn,recvbuf,1024);//接收包头
if(ret == -1)
{
ERR_EXIT("readline");
}
if(ret == 0)
{
printf("client close\n");
break;
}
fputs(recvbuf,stdout);
writen(conn,&recvbuf,strlen(recvbuf));
printf("writen finish\n");
}
}
void handle_sifchld(int sig)
{
while(waitpid(-1,NULL,WNOHANG) > 0)
;
}
void handle_sigpipe(int sig)
{
printf("recv a sig=%d\n", sig);
}
int main(void)
{
int listenfd;
if((listenfd = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP)) <0)
//listenfd = socket(PF_INET,SOCK_STREAM,0);
{
ERR_EXIT("socket");
}
struct sockaddr_in servaddr;
memset(&servaddr,0,sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(5188);
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
//servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
//inet_aton("127.0.0.1",&servaddr.sin_addr);
//开启地址重复利用(在TIME_WAIT未消失的情况下，允许服务器重启)
int on = 1;
if(setsockopt(listenfd,SOL_SOCKET,SO_REUSEADDR,&on,sizeof(on)) < 0)
ERR_EXIT("setsockopt");
if(bind(listenfd,(struct sockaddr*)&servaddr,sizeof(servaddr)) < 0)
ERR_EXIT("bind");
if(listen(listenfd,SOMAXCONN) < 0)
ERR_EXIT("listen");
struct sockaddr_in peeraddr;
socklen_t peerlen = sizeof(peeraddr);
int conn;
/*
pid_t pid;
while(1)
{
if((conn = accept(listenfd,(struct sockaddr*)&peeraddr, &peerlen)) < 0)
ERR_EXIT("accept");
printf("ip=%s port=%d\n",inet_ntoa(peeraddr.sin_addr),ntohs(peeraddr.sin_port));
pid = fork();
if(pid == -1)
ERR_EXIT("fork");
if(pid == 0)
{
close(listenfd);
do_service(conn);
exit(EXIT_SUCCESS);
}
else
{
close(conn);
}
}
*/
int i = 0;
int count= 0;
int client[FD_SETSIZE];
int maxi = 0;
for(i = 0;i<FD_SETSIZE; i++)
{
client[i] = -1;
}
int nready;
int maxfd = listenfd;
fd_set rset;
fd_set allset;
FD_ZERO(&rset);
FD_ZERO(&allset);
FD_SET(listenfd,&allset);
while(1)
{
rset = allset;
nready = select(maxfd+1,&rset,NULL,NULL,NULL);
if(nready == -1)
{
if(errno == EINTR)
continue;
ERR_EXIT("select");
}
if(nready == 0)
continue;
if(FD_ISSET(listenfd,&rset))
{
peerlen = sizeof(peeraddr);
conn = accept(listenfd,(struct sockaddr*)&peeraddr,&peerlen);
if(conn == -1)
ERR_EXIT("accept");
for(i = 0;i<FD_SETSIZE;i++)
{
if(client[i] < 0)
{
client[i] = conn;
if(i > maxi)
maxi = i;
break;
}
}
if(i == FD_SETSIZE)
{
fprintf(stderr, "too many clients\n");
exit(EXIT_FAILURE);
}
printf("ip=%s port=%d\n",inet_ntoa(peeraddr.sin_addr),ntohs(peeraddr.sin_port));
printf("count = %d\n",++count);
FD_SET(conn,&allset);
if(conn > maxfd)
maxfd = conn;
if(--nready <= 0)
continue;
}
for(i = 0; i<= maxi; i++)
{
conn = client[i];
if(conn == -1)
{
continue;
}
if(FD_ISSET(conn,&rset))
{
char recvbuf[1024] = {0};
int ret = readline(conn,recvbuf,1024);
if(ret == -1)
ERR_EXIT("readline");
if(ret == 0)
{
printf("client close\n");
FD_CLR(conn,&allset);
client[i] = -1;
close(conn);
}
fputs(recvbuf,stdout);
writen(conn,&recvbuf,strlen(recvbuf));
}
}
}
return 0;
}
本文由 Ryan 创作，采用 知识共享署名4.0 国际许可协议进行许可
本站文章除注明转载/出处外，均为本站原创或翻译，转载前请务必署名
最后编辑时间为:
2018/10/28 22:20