服务器客户端 与 有名管道

wpclub

大大们好，小菜刚开始linux下的编程。参考资料是APUE

我用有名管道实现了  一个服务端与多个客户端 通信的模型。
自己感觉思路是没有多少问题的。

服务端ctld <------------------> 客户端的child server

---------------------------------
参考的模型见附件

麻烦大大们看看我写的代码吧，mkfifo函数已经成功，可以在相应的目录看到已经生成的文件。现在的问题是，程序运行后堵塞在某个地方，无法继续运行下去

多谢大大们了
-------------------------------------------
head.h

#include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> #include <linux/limits.h> #include <string.h> #include <stdio.h> #define B_SIZE PIPE_BUF const char *CTLD = "/tmp/ctld"; typedef struct message { char fifo_name[B_SIZE];      char data[B_SIZE]; } my_msg;

--------------------------------------------
child_srv.c:

#include "head.h"

int main(){
int ctld_fifo,s_fifo;
  my_msg msg;
memset(&msg,'\0',sizeof(msg));

sprintf(msg.fifo_name,"/tmp/fifo%8d",getpid());

umask(0);
if (mkfifo(msg.fifo_name, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP))
   {
       perror("mkfifo srv";
       exit(1);
   }
if( s_fifo = open(msg.fifo_name,O_RDONLY) < 0 ) {

unlink(msg.fifo_name);
perror("open child srv";
}

if( ctld_fifo = open(CTLD,O_WRONLY)  < 0 ) {
perror("open ctld";
}
  
//先传递子服务程序的描述符
write(ctld_fifo, &msg, sizeof(msg));
printf("write srvfifo ok!\n";
while( read(s_fifo, &msg, sizeof(msg)) > 0){
//ctld传过来的数据

printf("\n\nsrv received data from ctld: %s\n",msg.data);
   //通过ctld_fifo传回数据
  strcpy(msg.data,"data in srv  to ctld\n\n";
  write(ctld_fifo, &msg, sizeof(msg));
printf("after database handle data!\n";
}
}

----------------------------------------------

ctld.c:

#include "head.h"
void
clr_fl(int fd, int flags)
{   int val;
    if ((val = fcntl(fd, F_GETFL, 0)) == -1)
    { perror("fcntl error";
        exit(1);
    }
    val &= ~flags; /* turn flags off */
    if (fcntl(fd, F_SETFL, val) == -1)
    {  perror("fcntl error";
       exit(1);
    }
}
int main(){
int s_fifo,ctld_fifo;
  my_msg msg;
//printf("before mkfifo\n";

//////下面部分为处理ctld部分的fifo，可以略去不看，只要知道生成了fifo就可以
unlink(CTLD);
umask(0);
   if (mkfifo(CTLD, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP))
   {
       perror("mkfifo ctld";
       exit(1);
   }

if ( (ctld_fifo = open(CTLD, O_RDONLY | O_NONBLOCK)) < 0  )perror("open error");
if ( open(CTLD, O_WRONLY) < 0 ) perror("open error");
clr_fl(ctld_fifo, O_NONBLOCK);
//////

printf("After mkfifo ctld_fifo");
//////先获取子服务程序的描述符
if( read(ctld_fifo, &msg, sizeof(msg)) < 0 ) perror("read child srv fd error");
printf("read ctldfifo ok!\n");

if (( s_fifo = open(msg.fifo_name, O_WRONLY)) == -1 ) perror("open child srv error");
    while(1){
  
//填充msg.data数据域

strcpy(msg.data,"\n\ninput :ctld's data !!!\n");
write(s_fifo, &msg, sizeof(msg));

//从ctld_fifo读取child srv传来的数据
  while( read(ctld_fifo, &msg, sizeof(msg)) > 0){

//将msg.data显示
printf("ctld received data:%s\n\n",msg.data);
sleep(10);

}
}
//close(s_fifo);


}

[ 本帖最后由 wpclub 于 2009-4-9 13:23 编辑 ]

wpclub

大大们帮帮忙吧，小菜谢谢了

wpclub

没人回答

helloghui

if( s_fifo = open(msg.fifo_name,O_RDONLY) < 0 )
client阻塞在此处，因为没有进程open这个有名管道for write.

In the normal case (O_NONBLOCK not specified), an open for read-only blocks until some other process opens the FIFO for writing. Similarly, an open for write-only blocks until some other process opens the FIFO for reading.