Thread: opened a file using popen() to run ls on server and return output to client(telnet)

Hi,
I am trying to implement telnet and execute "ls" command on the server side (called from the client side). For that, i have popen() a file and passed "ls" in a buffer from the client side to the server.

I am trying to read the output of this file in the same buffer using fgets(), line at a time.
Then writing the contents of this buffer to the client using write() system call.
But it only displays the last file read from the file and not the whole files in the directory.Whereas, it prints the whole list on the server side.

Code:

 fp = popen(buffer, "r");
  if (fp == NULL) {
    printf("Failed to run command\n" );
    exit;
  }
 while (fgets(buffer, sizeof(buffer)-1, fp) != NULL) {
    printf("%s", buffer); 
}
pclose(fp);
 n = write(newsockfd,buffer,strlen(buffer));
     if (n < 0) error("ERROR writing to socket");

Is there anyway that i can pass the whole list of files read from the file to the client using write system call???

Originally Posted by shwety

Hi,

Code:

 while (fgets(buffer, sizeof(buffer)-1, fp) != NULL) {
    printf("%s", buffer); 
}
pclose(fp);
 n = write(newsockfd,buffer,strlen(buffer));
     if (n < 0) error("ERROR writing to socket");

Is there anyway that i can pass the whole list of files read from the file to the client using write system call???

Yes. Try moving the call to write and the error checking inside your while (fgets) loop. Read a line, write a line, read a line, write a line. Not read 100 lines, each into the same place, then write 1.

thanks for the reply !

I did try to do it that way but at run time it used to read and display just 3 files on server side and display the first on the client side, and then terminate saying "broken pipe".

Is there any other way this can be done?

This is probably one of the easier ways. Perhaps I can help you figure out your broken pipe issue if you posted all of your code.