wraith-ircbot/src/bg.c

/*
 * bg.c -- handles:
 *   moving the process to the background, i.e. forking, while keeping threads
 *   happy.
 *
 */

#include "common.h"
#include "bg.h"
#include "main.h"
#include <signal.h>
#ifdef CRAZY_TRACE
#include <sys/ptrace.h>
#endif

time_t  lastfork = 0;

/* Do everything we normally do after we have split off a new
 * process to the background. This includes writing a PID file
 * and informing the user of the split.
 */
static void bg_do_detach(pid_t) __attribute__((noreturn));

static void bg_do_detach(pid_t p)
{
  FILE *fp = NULL;

  /* Need to attempt to write pid now, not later. */
  unlink(conf.bot->pid_file);
  fp = fopen(conf.bot->pid_file, "w");
  if (fp != NULL) {
    fprintf(fp, "%u\n", p);
    if (fflush(fp)) {
      /* Kill bot incase a botchk is run from crond. */
      printf(EGG_NOWRITE, conf.bot->pid_file);
      printf("  Try freeing some disk space\n");
      fclose(fp);
      unlink(conf.bot->pid_file);
      exit(1);
    }
    fclose(fp);
  } else
    printf(EGG_NOWRITE, conf.bot->pid_file);
#ifdef HUB
  printf("Launched into the background  (pid: %d)\n\n", p);
#else /* LEAF */
  printf("%s launched into the background  (pid: %d)\n\n", conf.bot->nick, p);
#endif /* HUB */

#ifndef CYGWIN_HACKS
  setpgid(p, p);
#endif /* !CYGWIN_HACKS */
  exit(0);
}

void bg_do_split(void)
{
  /* Split off a new process.
   */
  int xx = fork();

  if (xx == -1)
    fatal("CANNOT FORK PROCESS.", 0);
  if (xx != 0)		/* parent */
    bg_do_detach(xx);
#ifdef CRAZY_TRACE
  else			/* new child */
    /* block ptrace? */
# ifdef __linux__
    ptrace(PTRACE_TRACEME, 0, NULL, NULL);
# endif
# ifdef __FreeBSD__
    ptrace(PT_TRACE_ME, 0, NULL, NULL);
# endif
#endif /* CRAZY_TRACE */

}

void do_fork() {
  int xx;

  xx = fork();
  if (xx == -1)
    return;
  if (xx != 0) {
      FILE *fp;
      unlink(conf.bot->pid_file);
      fp = fopen(conf.bot->pid_file, "w");
      if (fp != NULL) {
        fprintf(fp, "%u\n", xx);
        fclose(fp);
      }
  }
  if (xx) {
#if HAVE_SETPGID
    setpgid(xx, xx);
#endif
    exit(0);
  }
  lastfork = now;
}