通过捕捉SIGCHLD信号捕捉僵尸进程，可解决多个子进程同时连接的情况
//服务器端
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
void error_handling(char* message)
{
fputs(message,stderr);
fputc('\n',stderr);
exit(1);
}
void handle_sigchld(int sig)
{
while (waitpid(-1, NULL, WNOHANG) > 0);
}
ssize_t readn(int fd,void* buf,size_t count)
{
size_t nleft=count; //剩余字节数
ssize_t nread; //已收字节数
char* bufp=(char*)buf; //char指针指向buf
while(nleft>0)
{
if((nread=read(fd,bufp,nleft))<0)
{
if(errno==EINTR) //读信号中断
{
continue;
return -1;
}
}
else if(nread==0) //对等方关闭
{
return count-nleft;
}
bufp+=nread;
nleft-=nread;
}
return count;
}
ssize_t written(int fd,const void* buf,size_t count)
{
size_t nleft=count;
ssize_t nwritten;
char *bufp=(char*)buf;
while(nleft>0)
{
if((nwritten=write(fd,bufp,nleft))<0)
{
if(errno==EINTR)
{
continue;
return -1;
}
}
else if(nwritten==0)
continue;
bufp+=nwritten;
nleft-=nwritten;
}
return count;
}
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;
else
return ret;
}
}
//因为readline()用recvpeek()封装的，所以readline()只能用于套接口
ssize_t readline(int sockfd,void* buf,size_t maxline)
{
int ret;
char* bufp=buf;
int nleft=maxline;
int nread;
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)
error_handling("readline");
return ret;
}
}
nleft-=nread;
ret=readn(sockfd,bufp,nread);
if(ret<0)
error_handling("readline_readn");
bufp+=nread;
}
return -1;
}
int main()
{
signal(SIGCHLD, handle_sigchld);
int listenfd=socket(AF_INET,SOCK_STREAM,0);
if(listenfd<0)
error_handling("socket");
// struct packet sendbuf;
//struct packet recvbuf;
// memset(&sendbuf,0,sizeof(sendbuf));
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);
int on=1;
if(setsockopt(listenfd,SOL_SOCKET,SO_REUSEADDR,&on,sizeof(on))<0)
error_handling("socket");
if(bind(listenfd,(struct sockaddr*)&servaddr,sizeof(servaddr))<0)
error_handling("bind");
if(listen(listenfd,SOMAXCONN)<0)
error_handling("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)
error_handling("accept");
printf("ip=%s port=%d\n",inet_ntoa(peeraddr.sin_addr),ntohs(peeraddr.sin_port));
pid=fork();
if(pid==-1)
error_handling("fork");
if(pid==0)
{
close(listenfd);
char recvbuf[1024];
while(1)
{
memset(recvbuf,0,sizeof(recvbuf));
int ret=readline(conn,recvbuf,1024);
if(ret==-1)
error_handling("fork");
fputs(recvbuf,stdout);
write(conn,recvbuf,ret);
}
}
else
close(conn);
}
return 0;
}
//客户端
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
void error_handling(char* message)
{
fputs(message,stderr);
fputc('\n',stderr);
exit(1);
}
ssize_t readn(int fd,void* buf,size_t count)
{
size_t nleft=count; //剩余字节数
ssize_t nread; //已收字节数
char* bufp=(char*)buf; //char指针指向buf
while(nleft>0)
{
if((nread=read(fd,bufp,nleft))<0)
{
if(errno==EINTR) //读信号中断
{
continue;
return -1;
}
}
else if(nread==0) //对等方关闭
{
return count-nleft;
}
bufp+=nread;
nleft-=nread;
}
return count;
}
ssize_t written(int fd,const void* buf,size_t count)
{
size_t nleft=count;
ssize_t nwritten;
char *bufp=(char*)buf;
while(nleft>0)
{
if((nwritten=write(fd,bufp,nleft))<0)
{
if(errno==EINTR)
{
continue;
return -1;
}
}
else if(nwritten==0)
continue;
bufp+=nwritten;
nleft-=nwritten;
}
return count;
}
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;
else
return ret;
}
}
//因为readline()用recvpeek()封装的，所以readline()只能用于套接口
ssize_t readline(int sockfd,void* buf,size_t maxline)
{
int ret;
char* bufp=buf;
int nleft=maxline;
int nread;
while(1)
{
ret=recv_peek(sockfd,bufp,nleft);
if(ret<0)
return ret; //此处不用再判断是否是信号中断，因为在recv()以判断
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)
error_handling("readline");
return ret;
}
}
nleft-=nread;
ret=readn(sockfd,bufp,nread);
if(ret<0)
error_handling("readline_readn");
bufp+=nread;
}
return -1;
}
int main()
{
int sock[5];
int i;
for(i=0;i<5;++i)
{
sock[i]=socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
if(sock[i]<0)
error_handling("sock");
struct sockaddr_in servaddr;
memset(&servaddr,0,sizeof(servaddr));
servaddr.sin_family=AF_INET;
servaddr.sin_port=htons(5188);
servaddr.sin_addr.s_addr=inet_addr("127.0.0.1");
if(connect(sock[i],(struct sockaddr*)&servaddr,sizeof (servaddr))<0)
error_handling("connect");
struct sockaddr_in localaddr;
socklen_t addrlen=sizeof(localaddr);
if(getsockname(sock[i],(struct sockaddr*)&localaddr,&addrlen)<0)
error_handling("getsockname");
printf("ip=%s port=%d\n",inet_ntoa(localaddr.sin_addr),ntohs(localaddr.sin_port));
// struct packet sendbuf;
// struct packet recvbuf;
char sendbuf[1024]={0};
char recvbuf[1024]={0};
int n;
while(fgets(sendbuf,sizeof(sendbuf),stdin)!=NULL)
{
written(sock[i],&sendbuf,strlen(sendbuf));
int ret=readline(sock[i],recvbuf,1024);
if(ret==-1)
error_handling("readline");
else if(ret==0)
{
printf("client close\n");
break;}
fputs(recvbuf,stdout);
memset(&sendbuf,0,sizeof(sendbuf));
memset(&sendbuf,0,sizeof(sendbuf));
}
close(sock[i]);
}
return 0;
}