getloadavg.c

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#  endif /* SUNOS_5 */

# endif /* LOAD_AVE_TYPE */

/* Put the 1 minute, 5 minute and 15 minute load averages
   into the first NELEM elements of LOADAVG.
   Return the number written (never more than 3, but may be less than NELEM),
   or -1 if an error occurred.  */

int
getloadavg (loadavg, nelem)
     double loadavg[];
     int nelem;
{
  int elem = 0;			/* Return value.  */

# ifdef NO_GET_LOAD_AVG
#  define LDAV_DONE
  /* Set errno to zero to indicate that there was no particular error;
     this function just can't work at all on this system.  */
  errno = 0;
  elem = -1;
# endif

# if !defined (LDAV_DONE) && defined (HAVE_LIBKSTAT)
/* Use libkstat because we don't have to be root.  */
#  define LDAV_DONE
  kstat_ctl_t *kc;
  kstat_t *ksp;
  kstat_named_t *kn;

  kc = kstat_open ();
  if (kc == 0)
    return -1;
  ksp = kstat_lookup (kc, "unix", 0, "system_misc");
  if (ksp == 0 )
    return -1;
  if (kstat_read (kc, ksp, 0) == -1)
    return -1;


  kn = kstat_data_lookup (ksp, "avenrun_1min");
  if (kn == 0)
    {
      /* Return -1 if no load average information is available.  */
      nelem = 0;
      elem = -1;
    }

  if (nelem >= 1)
    loadavg[elem++] = (double) kn->value.ul/FSCALE;

  if (nelem >= 2)
    {
      kn = kstat_data_lookup (ksp, "avenrun_5min");
      if (kn != 0)
	{
	  loadavg[elem++] = (double) kn->value.ul/FSCALE;

	  if (nelem >= 3)
	    {
	      kn = kstat_data_lookup (ksp, "avenrun_15min");
	      if (kn != 0)
		loadavg[elem++] = (double) kn->value.ul/FSCALE;
	    }
	}
    }

  kstat_close (kc);
# endif /* HAVE_LIBKSTAT */

# if !defined (LDAV_DONE) && defined (hpux) && defined (HAVE_PSTAT_GETDYNAMIC)
/* Use pstat_getdynamic() because we don't have to be root.  */
#  define LDAV_DONE
#  undef LOAD_AVE_TYPE

  struct pst_dynamic dyn_info;
  if (pstat_getdynamic (&dyn_info, sizeof (dyn_info), 0, 0) < 0)
    return -1;
  if (nelem > 0)
    loadavg[elem++] = dyn_info.psd_avg_1_min;
  if (nelem > 1)
    loadavg[elem++] = dyn_info.psd_avg_5_min;
  if (nelem > 2)
    loadavg[elem++] = dyn_info.psd_avg_15_min;

# endif /* hpux && HAVE_PSTAT_GETDYNAMIC */

# if !defined (LDAV_DONE) && defined (__linux__)
#  define LDAV_DONE
#  undef LOAD_AVE_TYPE

#  ifndef LINUX_LDAV_FILE
#   define LINUX_LDAV_FILE "/proc/loadavg"
#  endif

  char ldavgbuf[40];
  double load_ave[3];
  int fd, count;

  fd = open (LINUX_LDAV_FILE, O_RDONLY);
  if (fd == -1)
    return -1;
  count = read (fd, ldavgbuf, 40);
  (void) close (fd);
  if (count <= 0)
    return -1;

  /* The following sscanf must use the C locale.  */
  setlocale (LC_NUMERIC, "C");
  count = sscanf (ldavgbuf, "%lf %lf %lf",
		  &load_ave[0], &load_ave[1], &load_ave[2]);
  setlocale (LC_NUMERIC, "");
  if (count < 1)
    return -1;

  for (elem = 0; elem < nelem && elem < count; elem++)
    loadavg[elem] = load_ave[elem];

  return elem;

# endif /* __linux__ */

# if !defined (LDAV_DONE) && defined (__NetBSD__)
#  define LDAV_DONE
#  undef LOAD_AVE_TYPE

#  ifndef NETBSD_LDAV_FILE
#   define NETBSD_LDAV_FILE "/kern/loadavg"
#  endif

  unsigned long int load_ave[3], scale;
  int count;
  FILE *fp;

  fp = fopen (NETBSD_LDAV_FILE, "r");
  if (fp == NULL)
    return -1;
  count = fscanf (fp, "%lu %lu %lu %lu\n",
		  &load_ave[0], &load_ave[1], &load_ave[2],
		  &scale);
  (void) fclose (fp);
  if (count != 4)
    return -1;

  for (elem = 0; elem < nelem; elem++)
    loadavg[elem] = (double) load_ave[elem] / (double) scale;

  return elem;

# endif /* __NetBSD__ */

# if !defined (LDAV_DONE) && defined (NeXT)
#  define LDAV_DONE
  /* The NeXT code was adapted from iscreen 3.2.  */

  host_t host;
  struct processor_set_basic_info info;
  unsigned info_count;

  /* We only know how to get the 1-minute average for this system,
     so even if the caller asks for more than 1, we only return 1.  */

  if (!getloadavg_initialized)
    {
      if (processor_set_default (host_self (), &default_set) == KERN_SUCCESS)
	getloadavg_initialized = 1;
    }

  if (getloadavg_initialized)
    {
      info_count = PROCESSOR_SET_BASIC_INFO_COUNT;
      if (processor_set_info (default_set, PROCESSOR_SET_BASIC_INFO, &host,
			      (processor_set_info_t) &info, &info_count)
	  != KERN_SUCCESS)
	getloadavg_initialized = 0;
      else
	{
	  if (nelem > 0)
	    loadavg[elem++] = (double) info.load_average / LOAD_SCALE;
	}
    }

  if (!getloadavg_initialized)
    return -1;
# endif /* NeXT */

# if !defined (LDAV_DONE) && defined (UMAX)
#  define LDAV_DONE
/* UMAX 4.2, which runs on the Encore Multimax multiprocessor, does not
   have a /dev/kmem.  Information about the workings of the running kernel
   can be gathered with inq_stats system calls.
   We only know how to get the 1-minute average for this system.  */

  struct proc_summary proc_sum_data;
  struct stat_descr proc_info;
  double load;
  register unsigned int i, j;

  if (cpus == 0)
    {
      register unsigned int c, i;
      struct cpu_config conf;
      struct stat_descr desc;

      desc.sd_next = 0;
      desc.sd_subsys = SUBSYS_CPU;
      desc.sd_type = CPUTYPE_CONFIG;
      desc.sd_addr = (char *) &conf;
      desc.sd_size = sizeof conf;

      if (inq_stats (1, &desc))
	return -1;

      c = 0;
      for (i = 0; i < conf.config_maxclass; ++i)
	{
	  struct class_stats stats;
	  bzero ((char *) &stats, sizeof stats);

	  desc.sd_type = CPUTYPE_CLASS;
	  desc.sd_objid = i;
	  desc.sd_addr = (char *) &stats;
	  desc.sd_size = sizeof stats;

	  if (inq_stats (1, &desc))
	    return -1;

	  c += stats.class_numcpus;
	}
      cpus = c;
      samples = cpus < 2 ? 3 : (2 * cpus / 3);
    }

  proc_info.sd_next = 0;
  proc_info.sd_subsys = SUBSYS_PROC;
  proc_info.sd_type = PROCTYPE_SUMMARY;
  proc_info.sd_addr = (char *) &proc_sum_data;
  proc_info.sd_size = sizeof (struct proc_summary);
  proc_info.sd_sizeused = 0;

  if (inq_stats (1, &proc_info) != 0)
    return -1;

  load = proc_sum_data.ps_nrunnable;
  j = 0;
  for (i = samples - 1; i > 0; --i)
    {
      load += proc_sum_data.ps_nrun[j];
      if (j++ == PS_NRUNSIZE)
	j = 0;
    }

  if (nelem > 0)
    loadavg[elem++] = load / samples / cpus;
# endif /* UMAX */

# if !defined (LDAV_DONE) && defined (DGUX)
#  define LDAV_DONE
  /* This call can return -1 for an error, but with good args
     it's not supposed to fail.  The first argument is for no
     apparent reason of type `long int *'.  */
  dg_sys_info ((long int *) &load_info,
	       DG_SYS_INFO_LOAD_INFO_TYPE,
	       DG_SYS_INFO_LOAD_VERSION_0);

  if (nelem > 0)
    loadavg[elem++] = load_info.one_minute;
  if (nelem > 1)
    loadavg[elem++] = load_info.five_minute;
  if (nelem > 2)
    loadavg[elem++] = load_info.fifteen_minute;
# endif /* DGUX */

# if !defined (LDAV_DONE) && defined (apollo)
#  define LDAV_DONE
/* Apollo code from [e-mail] (Ray Lischner).

   This system call is not documented.  The load average is obtained as
   three long integers, for the load average over the past minute,
   five minutes, and fifteen minutes.  Each value is a scaled integer,
   with 16 bits of integer part and 16 bits of fraction part.

   I'm not sure which operating system first supported this system call,
   but I know that SR10.2 supports it.  */

  extern void proc1_$get_loadav ();
  unsigned long load_ave[3];

  proc1_$get_loadav (load_ave);

  if (nelem > 0)
    loadavg[elem++] = load_ave[0] / 65536.0;
  if (nelem > 1)
    loadavg[elem++] = load_ave[1] / 65536.0;
  if (nelem > 2)
    loadavg[elem++] = load_ave[2] / 65536.0;
# endif /* apollo */

# if !defined (LDAV_DONE) && defined (OSF_MIPS)
#  define LDAV_DONE

  struct tbl_loadavg load_ave;
  table (TBL_LOADAVG, 0, &load_ave, 1, sizeof (load_ave));
  loadavg[elem++]
    = (load_ave.tl_lscale == 0
       ? load_ave.tl_avenrun.d[0]
       : (load_ave.tl_avenrun.l[0] / (double) load_ave.tl_lscale));
# endif	/* OSF_MIPS */

# if !defined (LDAV_DONE) && (defined (__MSDOS__) || defined (WINDOWS32))
#  define LDAV_DONE

  /* A faithful emulation is going to have to be saved for a rainy day.  */
  for ( ; elem < nelem; elem++)
    {
      loadavg[elem] = 0.0;
    }
# endif  /* __MSDOS__ || WINDOWS32 */

# if !defined (LDAV_DONE) && defined (OSF_ALPHA)
#  define LDAV_DONE

  struct tbl_loadavg load_ave;
  table (TBL_LOADAVG, 0, &load_ave, 1, sizeof (load_ave));
  for (elem = 0; elem < nelem; elem++)
    loadavg[elem]
      = (load_ave.tl_lscale == 0
       ? load_ave.tl_avenrun.d[elem]
       : (load_ave.tl_avenrun.l[elem] / (double) load_ave.tl_lscale));
# endif /* OSF_ALPHA */

# if !defined (LDAV_DONE) && defined (VMS)
  /* VMS specific code -- read from the Load Ave driver.  */

  LOAD_AVE_TYPE load_ave[3];
  static int getloadavg_initialized = 0;
#  ifdef eunice
  struct
  {
    int dsc$w_length;
    char *dsc$a_pointer;
  } descriptor;
#  endif

  /* Ensure that there is a channel open to the load ave device.  */
  if (!getloadavg_initialized)
    {
      /* Attempt to open the channel.  */
#  ifdef eunice
      descriptor.dsc$w_length = 18;
      descriptor.dsc$a_pointer = "$$VMS_LOAD_AVERAGE";
#  else
      $DESCRIPTOR (descriptor, "LAV0:");
#  endif
      if (sys$assign (&descriptor, &channel, 0, 0) & 1)
	getloadavg_initialized = 1;
    }

  /* Read the load average vector.  */
  if (getloadavg_initialized
      && !(sys$qiow (0, channel, IO$_READVBLK, 0, 0, 0,
		     load_ave, 12, 0, 0, 0, 0) & 1))
    {
      sys$dassgn (channel);
      getloadavg_initialized = 0;
    }

  if (!getloadavg_initialized)
    return -1;
# endif /* VMS */

# if !defined (LDAV_DONE) && defined(LOAD_AVE_TYPE) && !defined(VMS)

  /* UNIX-specific code -- read the average from /dev/kmem.  */

#  define LDAV_PRIVILEGED		/* This code requires special installation.  */

  LOAD_AVE_TYPE load_ave[3];

  /* Get the address of LDAV_SYMBOL.  */
  if (offset == 0)
    {
#  ifndef sgi
#   ifndef NLIST_STRUCT
      strcpy (nl[0].n_name, LDAV_SYMBOL);
      strcpy (nl[1].n_name, "");
#   else /* NLIST_STRUCT */
#    ifdef NLIST_NAME_UNION
      nl[0].n_un.n_name = LDAV_SYMBOL;
      nl[1].n_un.n_name = 0;
#    else /* not NLIST_NAME_UNION */
      nl[0].n_name = LDAV_SYMBOL;
      nl[1].n_name = 0;
#    endif /* not NLIST_NAME_UNION */
#   endif /* NLIST_STRUCT */

#   ifndef SUNOS_5
      if (
#    if !(defined (_AIX) && !defined (ps2))
	  nlist (KERNEL_FILE, nl)
#    else  /* _AIX */
	  knlist (nl, 1, sizeof (nl[0]))
#    endif
	  >= 0)
	  /* Omit "&& nl[0].n_type != 0 " -- it breaks on Sun386i.  */
	  {
#    ifdef FIXUP_KERNEL_SYMBOL_ADDR
	    FIXUP_KERNEL_SYMBOL_ADDR (nl);
#    endif
	    offset = nl[0].n_value;
	  }
#   endif /* !SUNOS_5 */
#  else  /* sgi */
      int ldav_off;

      ldav_off = sysmp (MP_KERNADDR, MPKA_AVENRUN);
      if (ldav_off != -1)
	offset = (long) ldav_off & 0x7fffffff;
#  endif /* sgi */
    }

  /* Make sure we have /dev/kmem open.  */
  if (!getloadavg_initialized)
    {
#  ifndef SUNOS_5
      channel = open ("/dev/kmem", 0);
      if (channel >= 0)
	{
	  /* Set the channel to close on exec, so it does not
	     litter any child's descriptor table.  */
#   ifdef FD_SETFD
#    ifndef FD_CLOEXEC
#     define FD_CLOEXEC 1
#    endif
	  (void) fcntl (channel, F_SETFD, FD_CLOEXEC);
#   endif
	  getloadavg_initialized = 1;
	}
#  else /* SUNOS_5 */
      /* We pass 0 for the kernel, corefile, and swapfile names
	 to use the currently running kernel.  */
      kd = kvm_open (0, 0, 0, O_RDONLY, 0);
      if (kd != 0)
	{
	  /* nlist the currently running kernel.  */
	  kvm_nlist (kd, nl);
	  offset = nl[0].n_value;
	  getloadavg_initialized = 1;
	}
#  endif /* SUNOS_5 */
    }

  /* If we can, get the load average values.  */
  if (offset && getloadavg_initialized)
    {
      /* Try to read the load.  */
#  ifndef SUNOS_5
      if (lseek (channel, offset, 0) == -1L
	  || read (channel, (char *) load_ave, sizeof (load_ave))
	  != sizeof (load_ave))
	{
	  close (channel);
	  getloadavg_initialized = 0;
	}
#  else  /* SUNOS_5 */
      if (kvm_read (kd, offset, (char *) load_ave, sizeof (load_ave))
	  != sizeof (load_ave))
        {
          kvm_close (kd);
          getloadavg_initialized = 0;
	}
#  endif /* SUNOS_5 */
    }

  if (offset == 0 || !getloadavg_initialized)
    return -1;
# endif /* LOAD_AVE_TYPE and not VMS */

# if !defined (LDAV_DONE) && defined (LOAD_AVE_TYPE) /* Including VMS.  */
  if (nelem > 0)
    loadavg[elem++] = LDAV_CVT (load_ave[0]);
  if (nelem > 1)
    loadavg[elem++] = LDAV_CVT (load_ave[1]);
  if (nelem > 2)
    loadavg[elem++] = LDAV_CVT (load_ave[2]);

#  define LDAV_DONE
# endif /* !LDAV_DONE && LOAD_AVE_TYPE */

# ifdef LDAV_DONE
  return elem;
# else
  /* Set errno to zero to indicate that there was no particular error;
     this function just can't work at all on this system.  */
  errno = 0;
  return -1;
# endif
}

#endif /* ! HAVE_GETLOADAVG */

#ifdef TEST
void
main (argc, argv)
     int argc;
     char **argv;
{
  int naptime = 0;

  if (argc > 1)
    naptime = atoi (argv[1]);

  while (1)
    {
      double avg[3];
      int loads;

      errno = 0;		/* Don't be misled if it doesn't set errno.  */
      loads = getloadavg (avg, 3);
      if (loads == -1)
	{
	  perror ("Error getting load average");
	  exit (1);
	}
      if (loads > 0)
	printf ("1-minute: %f  ", avg[0]);
      if (loads > 1)
	printf ("5-minute: %f  ", avg[1]);
      if (loads > 2)
	printf ("15-minute: %f  ", avg[2]);
      if (loads > 0)
	putchar ('\n');

      if (naptime == 0)
	break;
      sleep (naptime);
    }

  exit (0);
}
#endif /* TEST */