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