abort further processing of packet if length error detected in p_rr()

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

/*
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley.  The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getloadavg.c        6.1 (Berkeley) %G%";
#endif LIBC_SCCS and not lint

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

#include <nlist.h>
#include <paths.h>

static char *kmem = _PATH_KMEM;
static char *vmunix = _PATH_UNIX;

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;
{
       off_t lseek();
       static int need_nlist = 1;
       fixpt_t averunnable[3];
       int fscale, kmemfd, i;

       /* nlist() is slow; cache result */
       if (need_nlist) {
               if (nlist(vmunix, nl) != 0)
                       return (-1);
               if (nl[X_AVERUNNABLE].n_type == 0 || nl[X_FSCALE].n_type == 0)
                       return (-1);
               need_nlist = 0;
       }

       if ((kmemfd = open(kmem, O_RDONLY, 0)) < 0)
               return (-1);
       if (lseek(kmemfd, (off_t)nl[X_AVERUNNABLE].n_value, L_SET) == -1)
               goto bad;
       if (read(kmemfd, (char *)averunnable, sizeof(averunnable)) < 0)
               goto bad;
       if (lseek(kmemfd, (off_t)nl[X_FSCALE].n_value, L_SET) == -1)
               goto bad;
       if (read(kmemfd, (char *)&fscale, sizeof(fscale)) < 0)
               goto bad;
       (void) close(kmemfd);

       nelem = MIN(nelem, sizeof(averunnable) / sizeof(averunnable[0]));
       for (i = 0; i < nelem; i++)
               loadavg[i] = (double) averunnable[i] / fscale;
       return (nelem);

bad:
       (void) close(kmemfd);
       return (-1);
}