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/*
* lbcd kernel code for BSD.
*
* Written by Russ Allbery <eagle@eyrie.org>
* Copyright 2000, 2009, 2012
* The Board of Trustees of the Leland Stanford Junior University
*
* See LICENSE for licensing terms.
*/
#include <config.h>
#include <portable/system.h>
#include <fcntl.h>
#include <kvm.h>
#include <nlist.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/times.h>
#include <server/internal.h>
#include <util/messages.h>
#define C_KMEM "/dev/kmem"
#define C_VMUNIX "/bsd"
#ifndef PROGNAME
# define PROGNAME "lbcd"
#endif
static struct nlist nl[] = {
{ "_avenrun" },
{ "_boottime" },
{ NULL }
};
static kvm_t *kernel = NULL;
static int kernel_init = 0;
/*
* Sets up for later queries. Open the kernel memory file and find the
* address of the necessary variable. Exits on error.
*/
static int
kernel_open(void)
{
kernel = kvm_open(NULL, NULL, NULL, O_RDONLY, PROGNAME);
if (kernel == NULL)
sysdie("kvm_open failed");
if (kvm_nlist(kernel, nl) != 0)
sysdie("kvm_nlist failed");
kernel_init = 1;
return 0;
}
/*
* Close and free any resources for querying the kernel.
*/
static int
kernel_close(void)
{
if (!kernel_init)
return 0;
return kvm_close(kd);
}
/*
* Read a value from kernel memory, given its offset, and store it in the dest
* buffer. That buffer has space for dest_len octets.
*/
static void
kernel_read(off_t where, void *dest, int dest_len)
{
int status;
status = kvm_read(kernel, where, dest, dest_len);
if (status != 0)
sysdie("kvm_read failed");
}
/*
* Get the current load average from the kernel and return the one minute,
* five minute, and fifteen minute averages in the given parameters. Returns
* 0 on success and -1 on failure.
*/
int
kernel_getload(double *l1, double *l5, double *l15)
{
long load[3];
if (!kernel_init)
kernel_open();
if (nl[0].n_type == 0)
return -1;
kernel_read(nl[0].n_value, (void *) load, sizeof(load));
*l1 = (double) load[0] / FSCALE;
*l5 = (double) load[1] / FSCALE;
*l15 = (double) load[2] / FSCALE;
return 0;
}
/*
* Get the system uptime and return it in the boottime parameter. Returns 0
* on success and -1 on failure.
*/
int
kernel_getboottime(time_t *boottime)
{
struct timeval boot;
if (!kernel_init)
kernel_open();
if (nl[1].n_type == 0)
return -1;
kernel_read(nl[0].n_value, (void *) &boot, sizeof(boot));
*boottime = boot.tv_sec;
return 0;
}
/*
* Test routine.
*/
#ifdef MAIN
int
main(void)
{
double l1, l5, l15;
time_t boottime;
if (kernel_getload(&l1, &l5, &l15) == 0)
printf("load %.02f %.02f %.02f\n", l1, l5, l15);
if (kernel_getboottime(&boottime) == 0)
printf("booted at %s", ctime(&boottime));
return 0;
}
#endif
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