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Annotation of 43BSDReno/lib/libutil/getloadavg.c, revision 1.1.1.1

1.1       root        1: /*-
                      2:  * Copyright (c) 1989 The Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms are permitted provided
                      6:  * that: (1) source distributions retain this entire copyright notice and
                      7:  * comment, and (2) distributions including binaries display the following
                      8:  * acknowledgement:  ``This product includes software developed by the
                      9:  * University of California, Berkeley and its contributors'' in the
                     10:  * documentation or other materials provided with the distribution and in
                     11:  * all advertising materials mentioning features or use of this software.
                     12:  * Neither the name of the University nor the names of its contributors may
                     13:  * be used to endorse or promote products derived from this software without
                     14:  * specific prior written permission.
                     15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
                     16:  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
                     17:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     18:  */
                     19: 
                     20: #if defined(LIBC_SCCS) && !defined(lint)
                     21: static char sccsid[] = "@(#)getloadavg.c       6.2 (Berkeley) 6/29/90";
                     22: #endif /* LIBC_SCCS and not lint */
                     23: 
                     24: #include <sys/param.h>
                     25: #include <sys/types.h>
                     26: #include <sys/file.h>
                     27: #include <nlist.h>
                     28: 
                     29: static struct nlist nl[] = {
                     30:        { "_averunnable" },
                     31: #define        X_AVERUNNABLE   0
                     32:        { "_fscale" },
                     33: #define        X_FSCALE        1
                     34:        { "" },
                     35: };
                     36: 
                     37: /*
                     38:  *  getloadavg() -- Get system load averages.
                     39:  *
                     40:  *  Put `nelem' samples into `loadavg' array.
                     41:  *  Return number of samples retrieved, or -1 on error.
                     42:  */
                     43: getloadavg(loadavg, nelem)
                     44:        double loadavg[];
                     45:        int nelem;
                     46: {
                     47:        static int need_nlist = 1;
                     48:        fixpt_t averunnable[3];
                     49:        int fscale, kmemfd, i;
                     50:        int alreadyopen;
                     51: 
                     52:        if ((alreadyopen = kvm_openfiles(NULL, NULL, NULL)) == -1)
                     53:                return (-1);
                     54:        /* 
                     55:         * cache nlist 
                     56:         */
                     57:        if (need_nlist) {
                     58:                if (kvm_nlist(nl) != 0)
                     59:                        goto bad;
                     60:                need_nlist = 0;
                     61:        }
                     62:        if (kvm_read((off_t)nl[X_AVERUNNABLE].n_value, (char *)averunnable, 
                     63:            sizeof(averunnable)) != sizeof(averunnable))
                     64:                goto bad;
                     65:        if (kvm_read( (off_t)nl[X_FSCALE].n_value, (char *)&fscale, 
                     66:            sizeof(fscale)) != sizeof(fscale))
                     67:                goto bad;
                     68:        nelem = MIN(nelem, sizeof(averunnable) / sizeof(averunnable[0]));
                     69:        for (i = 0; i < nelem; i++)
                     70:                loadavg[i] = (double) averunnable[i] / fscale;
                     71:        if (!alreadyopen)
                     72:                kvm_close();
                     73:        return (nelem);
                     74: 
                     75: bad:
                     76:        if (!alreadyopen)
                     77:                kvm_close();
                     78:        return (-1);
                     79: }

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