macro and text revision (-mdoc version 3)

[unix-history] / usr / src / lib / libc / gen / getloadavg.c

/*-
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* %sccs.include.redist.c%
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getloadavg.c        6.2 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/file.h>
#include <nlist.h>

static struct nlist nl[] = {
       { "_averunnable" },
#define X_AVERUNNABLE   0
       { "_fscale" },
#define X_FSCALE        1
       { "" },
};

/*
*  getloadavg() -- Get system load averages.
*
*  Put `nelem' samples into `loadavg' array.
*  Return number of samples retrieved, or -1 on error.
*/
getloadavg(loadavg, nelem)
       double loadavg[];
       int nelem;
{
       static int need_nlist = 1;
       fixpt_t averunnable[3];
       int fscale, kmemfd, i;
       int alreadyopen;

       if ((alreadyopen = kvm_openfiles(NULL, NULL, NULL)) == -1)
               return (-1);
       /* 
        * cache nlist 
        */
       if (need_nlist) {
               if (kvm_nlist(nl) != 0)
                       goto bad;
               need_nlist = 0;
       }
       if (kvm_read((off_t)nl[X_AVERUNNABLE].n_value, (char *)averunnable, 
           sizeof(averunnable)) != sizeof(averunnable))
               goto bad;
       if (kvm_read( (off_t)nl[X_FSCALE].n_value, (char *)&fscale, 
           sizeof(fscale)) != sizeof(fscale))
               goto bad;
       nelem = MIN(nelem, sizeof(averunnable) / sizeof(averunnable[0]));
       for (i = 0; i < nelem; i++)
               loadavg[i] = (double) averunnable[i] / fscale;
       if (!alreadyopen)
               kvm_close();
       return (nelem);

bad:
       if (!alreadyopen)
               kvm_close();
       return (-1);
}