C/Daemonize

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
 
int pipefd;
 
/* call this function to deamonize */
int daemonize(void) {
  int pipefds[2];
  int i;
  unsigned char c;
 
  if (pipe(pipefds) == -1) {
    perror("pipe()");
    return 1;
  }
 
  i = fork();
  if (i < 0) {
    perror("fork()");
    return 1;
  }
  if (i > 0) {
    close(pipefds[1]);
    if (read(pipefds[0],&c,1) <= 0) {
      printf("An error occured, unable to determine if started successfully...\n");
      exit(1);
    }
    if (c == 1) {
      printf("An error occured while starting...\n");
      exit(1);
    } else if (c == 2) {
      printf("An error occured while deamonizing...\n");
      return 2;
    } else if (c != 0) {
      printf("An unknown return status was given (%d)...\n", c);
      exit(1);
    }
    printf("Started successfully!\n");
    exit(0);
  }
 
  close(pipefds[0]);
  pipefd = pipefds[1];
 
  if (setsid() < 0) {
    perror("setsid()");
    goto killChild;
  }
 
  umask(0);
 
  if ((chdir("/")) < 0) {
    perror("chdir()");
    goto killChild;
  }
 
  return 0;
 
killChild:
  c = 2;
  write(pipefds[1],&c,2);
  close(pipefds[1]);
  exit(1);
}
 
/* call this to indicate success, and detach from the terminal */
void daemonize_success(void) {
  int i;
  unsigned char c;
 
  i = open("/dev/null",O_RDWR);
  if (i < 0) {
    close(fileno(stderr));
    close(fileno(stdout));
    close(fileno(stdin));
  } else {
    dup2(i,fileno(stderr)); /* 2 = stderr */
    dup2(i,fileno(stdout)); /* 1 = stdout */
    dup2(i,fileno(stdin));  /* 0 = stdin */
    close(i);
  }
 
  c = 0;
  write(pipefd,&c,1);
  close(pipefd);
}
 
/* call this to indicate failure in the parent... you must still kill yourself - try exit(1) */
void daemonize_failure(void) {
  unsigned char c;
  c = 1;
  write(pipefd,&c,1);
  close(pipefd);
}