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Annotation of 43BSD/contrib/dsh/src/getloadave.c, revision 1.1.1.1

1.1       root        1: /*(@(#)getloadave.c    1.2             /ra/csr/presotto/hacks/src/worm/sccs/s.getloadave.c)*/
                      2: #include <sys/types.h>
                      3: #include <nlist.h>
                      4: #include <sys/stat.h>
                      5: 
                      6: #define MAXRETRIES 20
                      7: 
                      8: struct nlist nl[] = {
                      9: #define        NL_AVENRUN      0
                     10:        { "_avenrun" },
                     11:        0
                     12: };
                     13: int    kmemf = -1;             /* fd for kmem */
                     14: time_t vmunixdate = 0;         /* update time for vmunix */
                     15: 
                     16: initnlist ()
                     17: {
                     18:     int                        i;
                     19:     struct nlist       *nlp;
                     20:     struct stat                sbuf;
                     21: 
                     22:     i = stat ("/vmunix", &sbuf);
                     23:     if (i == -1) {
                     24:        error ("can't read /vmunix");
                     25:     }
                     26:     if (vmunixdate != sbuf.st_mtime) {
                     27:        for (i = 0; i < MAXRETRIES; sleep (5), i++) {
                     28:            for (nlp = &nl[sizeof (nl) / sizeof (nl[0])]; --nlp >= nl; ) {
                     29:                nlp->n_value = 0;
                     30:                nlp->n_type = 0;
                     31:            }
                     32:            nlist("/vmunix", nl);
                     33:            if (nl[0].n_value == 0) {
                     34:                warn ("/vmunix namelist botch");
                     35:                continue;
                     36:            }
                     37:            break;
                     38:        }
                     39:        if (i >= MAXRETRIES)
                     40:            exit (-1);
                     41:        vmunixdate = sbuf.st_mtime;
                     42:     }
                     43: 
                     44:     if (kmemf == -1) {
                     45:        kmemf = open("/dev/kmem", 0);
                     46:        if (kmemf < 0) {
                     47:            error ("opening /dev/kmem");
                     48:        }
                     49:     }
                     50: }
                     51: 
                     52: 
                     53: /*
                     54:  *     Get the current load average 
                     55:  */
                     56: getloadave (avenrun)
                     57: double *avenrun;
                     58: {
                     59:     double             template[3];
                     60: 
                     61:     initnlist ();
                     62:     (void) lseek(kmemf, (long)nl[NL_AVENRUN].n_value, 0);
                     63:     (void) read(kmemf, (char *)avenrun, sizeof (template));
                     64: }

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