A request from Ali regarding Back OS processes

[redhead]

I got a personal message from Ali, and I thought it would be better if it was placed here, besides the reply message is too long for the private message system to send it.

ali wrote on 08-11-2004 10:49 AM:
Think a program: executing back OS like services. How can I make this program with C/c++. Can you give me sample.

A back OS service? are you thinking of a deamon running in the background and not appearing in any joblist?

What OS is this to be run under ? windows/linux/OSF2/HP-UX ?

I have a solution for the *nix world, but windows is a different matter, it tends to not follow the ANSI standard so some of the system dependant calls are implemented different according to which compiler is beeing used.

*nix ei:

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <signal.h>

/*
 * Just a simple deamon making function, as suggested in
 * Unix Network programming, second edition.
 * fork() and close() all file descriptors with
 * stderr/stdout/stdin/etc, and finaly chroot your 
 * self to be running on your own.
 */

void deamon_init(const char* pname, int facility)
{
  int i;
  unsigned long pid;
  if((pid=fork())!=0)
    exit(0);
  setsid();
  signal(SIGHUP, SIG_IGN);
  if((pid=fork())!=0)
    exit(0);
  chdir("/");
  umask(0);
  for(i=0; i < MAXFD; i++)
    close(i);
}

int main(int argv, char* argc[])
{
  deamon_init(argv[0],0);
  /* 
   * rest of program will have no access to stdin/stdout/stderr 
   * And will only appear when the OS is questioned for hidden
   * processes
   */
  sleep(50);
  return 0;
}

Altho in the future a question like this would be better, if it were placed in the c/c++ programming section, so otheres in a simular situation can benefit from the solution