一个简单的客户/服务器应用(socket 学习)

/* 子进程为客户方，父进程为服务器方。当客户请求通过socket传送给服务器方时，服务器会将当前的系统时间返回给客户

该程序参考自《实战linux socket 编程 》 Warren W.Gay

*/

#include<stdio.h>

#include<stdlib.h>

#include<unistd.h>

#include<errno.h>

#include<time.h>

#include<string.h>

#include<sys/types.h>

#include<sys/socket.h>

#include<sys/wait.h>

int main(int argc,char **argv)

{

int z;

int s[2];

char *msgp;

int mlen;

char buf[80];

pid_t chpid;

z=socketpair(AF_LOCAL,SOCK_STREAM,0,s);

if(z==-1)

{

fprintf(stderr,"%s:socketpair(AF_LOCAL,SOCK_STREAM,0)\n",strerror(errno));

exit(1);

}

if((chpid=fork())==(pid_t)-1)

{

fprintf(stderr,"%s:fork(2)\n",strerror(errno));

exit(1);

}

else if(chpid==0)

{

/*子进程，客户端*/

char rxbuf[80];

printf("Parent PID is %ld",(long)getppid());

close(s[0]);

s[0]=-1;

msgp="%A %d-%b-%Y %1:%M %p";

mlen=strlen(msgp);

printf("Child sending request '%s'\n",msgp);

/*向服务器写入请求*/

z=write(s[1],msgp,mlen);

/*if(shutdown(s[1],SHUT_WR)==-1)

{

fprintf(stderr,"%s:shutdown(2)\n",strerror(errno));

exit(1);

} */

z=read(s[1],rxbuf,sizeof rxbuf);

if(z<0)

{

fprintf(stderr,"%s:read(2)\n",strerror(errno));

exit(1);

}

rxbuf[z]=0;

printf("Server returned '%s'\n",rxbuf);

fflush(stdout);

close(s[1]);

}

else

{

int status;

char txbuf[80];

time_t td;

printf("child PID is %ld",(long)chpid);

fflush(stdout);

close(s[1]);

s[1]=-1;

z=read(s[0],buf,sizeof buf);

if(z<0)

{

fprintf(stderr,"%s:read(2)\n",strerror(errno));

exit(1);

}

buf[z]=0;

time(&td);

strftime(txbuf,sizeof txbuf,buf,localtime(&td));

z=write(s[0],txbuf,strlen(txbuf));

if(z<0)

{

fprintf(stderr,"%s:write(2)\n",strerror(errno));

exit(1);

}

close(s[0]);

waitpid(chpid,&status,0);

}

return 0;

}