/* 
 * (c) The GRASP/AQUA Project, Glasgow University, 1994-1998
 *
 * $Id: system.c,v 1.11 2001/02/20 03:41:31 qrczak Exp $
 *
 * system Runtime Support
 */

/* The itimer stuff in this module is non-posix */
#define NON_POSIX_SOURCE

#include "Rts.h"
#include "stgio.h"

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#if TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif

#ifndef mingw32_TARGET_OS
# ifdef HAVE_SYS_WAIT_H
#  include <sys/wait.h>
# endif
#else
# include <windows.h> /* for Sleep */
#endif

#ifdef HAVE_VFORK_H
#include <vfork.h>
#endif

#ifdef HAVE_VFORK
#define fork vfork
#endif

StgInt
systemCmd(StgByteArray cmd)
{
#if defined(mingw32_TARGET_OS)
   /* There's no fork() under Windows, so we fall back on using libc's
      system() instead. (It in turn has problems, as it does not wait
      until the sub shell has finished before returning. Using Sleep()
      works around that.) */
  if (system(cmd) < 0) {
     cvtErrno();
     stdErrno();
     return -1;
  }
  Sleep(1000);
  return 0;
#else
    int pid;
    int wstat;

    switch(pid = fork()) {
    case -1:
	if (errno != EINTR) {
	    cvtErrno();
	    stdErrno();
	    return -1;
	}
    case 0:
      {
#ifdef HAVE_SETITIMER
	/* Reset the itimers in the child, so it doesn't get plagued
	 * by SIGVTALRM interrupts.
	 */
	struct timeval tv_null = { 0, 0 };
	struct itimerval itv;
	itv.it_interval = tv_null;
	itv.it_value = tv_null;
	setitimer(ITIMER_REAL, &itv, NULL);
	setitimer(ITIMER_VIRTUAL, &itv, NULL);
	setitimer(ITIMER_PROF, &itv, NULL);
#endif

	/* the child */
	execl("/bin/sh", "sh", "-c", cmd, NULL);
	_exit(127);
      }
    }

    while (waitpid(pid, &wstat, 0) < 0) {
	if (errno != EINTR) {
	    cvtErrno();
	    stdErrno();
	    return -1;
	}
    }

    if (WIFEXITED(wstat))
	return WEXITSTATUS(wstat);
    else if (WIFSIGNALED(wstat)) {
	ghc_errtype = ERR_INTERRUPTED;
	ghc_errstr = "system command interrupted";
    }
    else {
	/* This should never happen */
	ghc_errtype = ERR_OTHERERROR;
	ghc_errstr = "internal error (process neither exited nor signalled)";
    }
    return -1;
#endif
}