Very Computer

Cheers // Fredrik Roubert

--
M?llev?ngsv?gen 6c  |  +46 46 188127
SE-222 40 Lund      |  http://www.df.lth.se/~roubert/

-- ced

--
Chuck Dillon
Senior Software Engineer
NimbleGen Systems Inc.

Here's a function that daemonises a process.

Duke

/*
  * int daemonise()
  *
  *  This function creates a child of the the current process
  *  and turns it into a daemon using setsid().  The current
  *  process dies in here.
  *
  */

#include <sys/file.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <unistd.h>

int daemonise()
{
   int num_files;
   int fd;

   pid_t pgid;

   int cur_file;

   /* become a child; parent dies */
   pid= fork();
   if (pid == -1) {

     /* error */
     return(1);

   } else if (pid > 0) {

     /* this is the parent.  die */
     exit(0);

   } else {

     /* this is the child, do your thing */

     /* create a new session and become session leader. */
     /* This gets rid of the controlling terminal, too */
     pgid= setsid();
     if (pgid==-1) {
       /* error */
       return(2);
     }

     /* back before setsid(), you use to do this to */
     /* get rid of the controlling terminal */
     //    if (fd= open("/dev/tty", O_RDWR|O_NOCTTY) >= 0) {
     //      ioctl(fd, TIOCNOTTY, 0);
     //      (void) close(fd);
     //    } else {
     //      return(2);
     //    }

     /* close all file descriptors */
     num_files= getdtablesize();
     for (cur_file = 0; cur_file < num_files; cur_file++)
       (void) close(cur_file);

     /* attach file descriptors 0,1,2 to /dev/null */
     (void) open("/dev/null", O_RDONLY);
     (void) open("/dev/null", O_WRONLY);
     (void) dup(1);

   }

   /* that's it, we're a daemon. Pretty cool, huh? */
   return(0);

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