freebsd-dev/usr.bin/vmstat/vmstat.c
Tim J. Robbins 3c93cfb510 Reimplement the vmstat -f option (display fork statistics).
PR:		50924
Submitted by:	Ken Stailey (with a few changes)
2003-04-14 07:21:03 +00:00

825 lines
21 KiB
C

/*
* Copyright (c) 1980, 1986, 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1980, 1986, 1991, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif
#ifndef lint
static const char sccsid[] = "@(#)vmstat.c 8.1 (Berkeley) 6/6/93";
#endif
#include <sys/param.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/uio.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <sys/signal.h>
#include <sys/fcntl.h>
#include <sys/ioctl.h>
#include <sys/resource.h>
#include <sys/sysctl.h>
#include <sys/vmmeter.h>
#include <vm/vm_param.h>
#include <ctype.h>
#include <devstat.h>
#include <err.h>
#include <errno.h>
#include <kvm.h>
#include <limits.h>
#include <nlist.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <time.h>
#include <unistd.h>
static char da[] = "da";
static struct nlist namelist[] = {
#define X_CPTIME 0
{ "_cp_time" },
#define X_SUM 1
{ "_cnt" },
#define X_BOOTTIME 2
{ "_boottime" },
#define X_HZ 3
{ "_hz" },
#define X_STATHZ 4
{ "_stathz" },
#define X_NCHSTATS 5
{ "_nchstats" },
#define X_INTRNAMES 6
{ "_intrnames" },
#define X_EINTRNAMES 7
{ "_eintrnames" },
#define X_INTRCNT 8
{ "_intrcnt" },
#define X_EINTRCNT 9
{ "_eintrcnt" },
#ifdef notyet
#define X_DEFICIT 10
{ "_deficit" },
#define X_REC 11
{ "_rectime" },
#define X_PGIN 12
{ "_pgintime" },
#define X_XSTATS 13
{ "_xstats" },
#define X_END 14
#else
#define X_END 10
#endif
{ "" },
};
struct statinfo cur, last;
int num_devices, maxshowdevs;
long generation;
struct device_selection *dev_select;
int num_selected;
struct devstat_match *matches;
int num_matches = 0;
int num_devices_specified, num_selections;
long select_generation;
char **specified_devices;
devstat_select_mode select_mode;
struct vmmeter sum, osum;
int winlines = 20;
int nflag = 0;
kvm_t *kd;
#define FORKSTAT 0x01
#define INTRSTAT 0x02
#define MEMSTAT 0x04
#define SUMSTAT 0x08
#define TIMESTAT 0x10
#define VMSTAT 0x20
#define ZMEMSTAT 0x40
static void cpustats(void);
static void devstats(void);
static void dosysctl(char *);
static void domem(void);
static void dointr(void);
static void dosum(void);
static void doforkst(void);
static void dovmstat(u_int, int);
static void dozmem(void);
static void kread(int, void *, size_t);
static void needhdr(int);
static void printhdr(void);
static void usage(void);
static long pct(long, long);
static long getuptime(void);
char **getdrivedata(char **);
int
main(argc, argv)
int argc;
char **argv;
{
int c, todo;
u_int interval;
int reps;
char *memf, *nlistf;
char errbuf[_POSIX2_LINE_MAX];
memf = nlistf = NULL;
interval = reps = todo = 0;
maxshowdevs = 2;
while ((c = getopt(argc, argv, "c:fiM:mN:n:p:stw:z")) != -1) {
switch (c) {
case 'c':
reps = atoi(optarg);
break;
case 'f':
todo |= FORKSTAT;
break;
case 'i':
todo |= INTRSTAT;
break;
case 'M':
memf = optarg;
break;
case 'm':
todo |= MEMSTAT;
break;
case 'N':
nlistf = optarg;
break;
case 'n':
nflag = 1;
maxshowdevs = atoi(optarg);
if (maxshowdevs < 0)
errx(1, "number of devices %d is < 0",
maxshowdevs);
break;
case 'p':
if (devstat_buildmatch(optarg, &matches, &num_matches) != 0)
errx(1, "%s", devstat_errbuf);
break;
case 's':
todo |= SUMSTAT;
break;
case 't':
#ifdef notyet
todo |= TIMESTAT;
#else
errx(EX_USAGE, "sorry, -t is not (re)implemented yet");
#endif
break;
case 'w':
interval = atoi(optarg);
break;
case 'z':
todo |= ZMEMSTAT;
break;
case '?':
default:
usage();
}
}
argc -= optind;
argv += optind;
if (todo == 0)
todo = VMSTAT;
/*
* Discard setgid privileges if not the running kernel so that bad
* guys can't print interesting stuff from kernel memory.
*/
if (nlistf != NULL || memf != NULL)
setgid(getgid());
kd = kvm_openfiles(nlistf, memf, NULL, O_RDONLY, errbuf);
if (kd == 0)
errx(1, "kvm_openfiles: %s", errbuf);
setgid(getgid());
if ((c = kvm_nlist(kd, namelist)) != 0) {
if (c > 0) {
warnx("undefined symbols:");
for (c = 0;
c < (int)(sizeof(namelist)/sizeof(namelist[0]));
c++)
if (namelist[c].n_type == 0)
(void)fprintf(stderr, " %s",
namelist[c].n_name);
(void)fputc('\n', stderr);
} else
warnx("kvm_nlist: %s", kvm_geterr(kd));
exit(1);
}
if (todo & VMSTAT) {
struct winsize winsize;
/*
* Make sure that the userland devstat version matches the
* kernel devstat version. If not, exit and print a
* message informing the user of his mistake.
*/
if (devstat_checkversion(NULL) < 0)
errx(1, "%s", devstat_errbuf);
argv = getdrivedata(argv);
winsize.ws_row = 0;
(void) ioctl(STDOUT_FILENO, TIOCGWINSZ, (char *)&winsize);
if (winsize.ws_row > 0)
winlines = winsize.ws_row;
}
#define BACKWARD_COMPATIBILITY
#ifdef BACKWARD_COMPATIBILITY
if (*argv) {
interval = atoi(*argv);
if (*++argv)
reps = atoi(*argv);
}
#endif
if (interval) {
if (!reps)
reps = -1;
} else if (reps)
interval = 1;
if (todo & FORKSTAT)
doforkst();
if (todo & MEMSTAT)
domem();
if (todo & ZMEMSTAT)
dozmem();
if (todo & SUMSTAT)
dosum();
#ifdef notyet
if (todo & TIMESTAT)
dotimes();
#endif
if (todo & INTRSTAT)
dointr();
if (todo & VMSTAT)
dovmstat(interval, reps);
exit(0);
}
char **
getdrivedata(argv)
char **argv;
{
if ((num_devices = devstat_getnumdevs(NULL)) < 0)
errx(1, "%s", devstat_errbuf);
cur.dinfo = (struct devinfo *)malloc(sizeof(struct devinfo));
last.dinfo = (struct devinfo *)malloc(sizeof(struct devinfo));
bzero(cur.dinfo, sizeof(struct devinfo));
bzero(last.dinfo, sizeof(struct devinfo));
if (devstat_getdevs(NULL, &cur) == -1)
errx(1, "%s", devstat_errbuf);
num_devices = cur.dinfo->numdevs;
generation = cur.dinfo->generation;
specified_devices = (char **)malloc(sizeof(char *));
for (num_devices_specified = 0; *argv; ++argv) {
if (isdigit(**argv))
break;
num_devices_specified++;
specified_devices = (char **)realloc(specified_devices,
sizeof(char *) *
num_devices_specified);
specified_devices[num_devices_specified - 1] = *argv;
}
dev_select = NULL;
if (nflag == 0 && maxshowdevs < num_devices_specified)
maxshowdevs = num_devices_specified;
/*
* People are generally only interested in disk statistics when
* they're running vmstat. So, that's what we're going to give
* them if they don't specify anything by default. We'll also give
* them any other random devices in the system so that we get to
* maxshowdevs devices, if that many devices exist. If the user
* specifies devices on the command line, either through a pattern
* match or by naming them explicitly, we will give the user only
* those devices.
*/
if ((num_devices_specified == 0) && (num_matches == 0)) {
if (devstat_buildmatch(da, &matches, &num_matches) != 0)
errx(1, "%s", devstat_errbuf);
select_mode = DS_SELECT_ADD;
} else
select_mode = DS_SELECT_ONLY;
/*
* At this point, selectdevs will almost surely indicate that the
* device list has changed, so we don't look for return values of 0
* or 1. If we get back -1, though, there is an error.
*/
if (devstat_selectdevs(&dev_select, &num_selected, &num_selections,
&select_generation, generation, cur.dinfo->devices,
num_devices, matches, num_matches, specified_devices,
num_devices_specified, select_mode,
maxshowdevs, 0) == -1)
errx(1, "%s", devstat_errbuf);
return(argv);
}
long
getuptime()
{
static struct timeval boottime;
static time_t now;
time_t uptime;
if (boottime.tv_sec == 0)
kread(X_BOOTTIME, &boottime, sizeof(boottime));
(void)time(&now);
uptime = now - boottime.tv_sec;
if (uptime <= 0 || uptime > 60*60*24*365*10)
errx(1, "time makes no sense; namelist must be wrong");
return(uptime);
}
int hz, hdrcnt;
void
dovmstat(interval, reps)
u_int interval;
int reps;
{
struct vmtotal total;
time_t uptime, halfuptime;
struct devinfo *tmp_dinfo;
int mib[2];
size_t size;
uptime = getuptime();
halfuptime = uptime / 2;
(void)signal(SIGCONT, needhdr);
if (namelist[X_STATHZ].n_type != 0 && namelist[X_STATHZ].n_value != 0)
kread(X_STATHZ, &hz, sizeof(hz));
if (!hz)
kread(X_HZ, &hz, sizeof(hz));
for (hdrcnt = 1;;) {
if (!--hdrcnt)
printhdr();
kread(X_CPTIME, cur.cp_time, sizeof(cur.cp_time));
tmp_dinfo = last.dinfo;
last.dinfo = cur.dinfo;
cur.dinfo = tmp_dinfo;
last.snap_time = cur.snap_time;
/*
* Here what we want to do is refresh our device stats.
* getdevs() returns 1 when the device list has changed.
* If the device list has changed, we want to go through
* the selection process again, in case a device that we
* were previously displaying has gone away.
*/
switch (devstat_getdevs(NULL, &cur)) {
case -1:
errx(1, "%s", devstat_errbuf);
break;
case 1: {
int retval;
num_devices = cur.dinfo->numdevs;
generation = cur.dinfo->generation;
retval = devstat_selectdevs(&dev_select, &num_selected,
&num_selections, &select_generation,
generation, cur.dinfo->devices,
num_devices, matches, num_matches,
specified_devices,
num_devices_specified, select_mode,
maxshowdevs, 0);
switch (retval) {
case -1:
errx(1, "%s", devstat_errbuf);
break;
case 1:
printhdr();
break;
default:
break;
}
}
default:
break;
}
kread(X_SUM, &sum, sizeof(sum));
size = sizeof(total);
mib[0] = CTL_VM;
mib[1] = VM_TOTAL;
if (sysctl(mib, 2, &total, &size, NULL, 0) < 0) {
(void)printf("Can't get kerninfo: %s\n",
strerror(errno));
bzero(&total, sizeof(total));
}
(void)printf("%2d %1d %1d",
total.t_rq - 1, total.t_dw + total.t_pw, total.t_sw);
#define vmstat_pgtok(a) ((a) * sum.v_page_size >> 10)
#define rate(x) (((x) + halfuptime) / uptime) /* round */
(void)printf(" %7ld %6ld ", (long)vmstat_pgtok(total.t_avm),
(long)vmstat_pgtok(total.t_free));
(void)printf("%4lu ",
(u_long)rate(sum.v_vm_faults - osum.v_vm_faults));
(void)printf("%3lu ",
(u_long)rate(sum.v_reactivated - osum.v_reactivated));
(void)printf("%3lu ",
(u_long)rate(sum.v_swapin + sum.v_vnodein -
(osum.v_swapin + osum.v_vnodein)));
(void)printf("%3lu ",
(u_long)rate(sum.v_swapout + sum.v_vnodeout -
(osum.v_swapout + osum.v_vnodeout)));
(void)printf("%3lu ",
(u_long)rate(sum.v_tfree - osum.v_tfree));
(void)printf("%3lu ",
(u_long)rate(sum.v_pdpages - osum.v_pdpages));
devstats();
(void)printf("%4lu %4lu %3lu ",
(u_long)rate(sum.v_intr - osum.v_intr),
(u_long)rate(sum.v_syscall - osum.v_syscall),
(u_long)rate(sum.v_swtch - osum.v_swtch));
cpustats();
(void)printf("\n");
(void)fflush(stdout);
if (reps >= 0 && --reps <= 0)
break;
osum = sum;
uptime = interval;
/*
* We round upward to avoid losing low-frequency events
* (i.e., >= 1 per interval but < 1 per second).
*/
if (interval != 1)
halfuptime = (uptime + 1) / 2;
else
halfuptime = 0;
(void)sleep(interval);
}
}
void
printhdr()
{
int i, num_shown;
num_shown = (num_selected < maxshowdevs) ? num_selected : maxshowdevs;
(void)printf(" procs memory page%*s", 19, "");
if (num_shown > 1)
(void)printf(" disks %*s", num_shown * 4 - 7, "");
else if (num_shown == 1)
(void)printf("disk");
(void)printf(" faults cpu\n");
(void)printf(" r b w avm fre flt re pi po fr sr ");
for (i = 0; i < num_devices; i++)
if ((dev_select[i].selected)
&& (dev_select[i].selected <= maxshowdevs))
(void)printf("%c%c%d ", dev_select[i].device_name[0],
dev_select[i].device_name[1],
dev_select[i].unit_number);
(void)printf(" in sy cs us sy id\n");
hdrcnt = winlines - 2;
}
/*
* Force a header to be prepended to the next output.
*/
void
needhdr(dummy)
int dummy __unused;
{
hdrcnt = 1;
}
#ifdef notyet
void
dotimes()
{
u_int pgintime, rectime;
kread(X_REC, &rectime, sizeof(rectime));
kread(X_PGIN, &pgintime, sizeof(pgintime));
kread(X_SUM, &sum, sizeof(sum));
(void)printf("%u reclaims, %u total time (usec)\n",
sum.v_pgrec, rectime);
(void)printf("average: %u usec / reclaim\n", rectime / sum.v_pgrec);
(void)printf("\n");
(void)printf("%u page ins, %u total time (msec)\n",
sum.v_pgin, pgintime / 10);
(void)printf("average: %8.1f msec / page in\n",
pgintime / (sum.v_pgin * 10.0));
}
#endif
long
pct(top, bot)
long top, bot;
{
long ans;
if (bot == 0)
return(0);
ans = (quad_t)top * 100 / bot;
return (ans);
}
#define PCT(top, bot) pct((long)(top), (long)(bot))
void
dosum()
{
struct nchstats lnchstats;
long nchtotal;
kread(X_SUM, &sum, sizeof(sum));
(void)printf("%9u cpu context switches\n", sum.v_swtch);
(void)printf("%9u device interrupts\n", sum.v_intr);
(void)printf("%9u software interrupts\n", sum.v_soft);
(void)printf("%9u traps\n", sum.v_trap);
(void)printf("%9u system calls\n", sum.v_syscall);
(void)printf("%9u kernel threads created\n", sum.v_kthreads);
(void)printf("%9u fork() calls\n", sum.v_forks);
(void)printf("%9u vfork() calls\n", sum.v_vforks);
(void)printf("%9u rfork() calls\n", sum.v_rforks);
(void)printf("%9u swap pager pageins\n", sum.v_swapin);
(void)printf("%9u swap pager pages paged in\n", sum.v_swappgsin);
(void)printf("%9u swap pager pageouts\n", sum.v_swapout);
(void)printf("%9u swap pager pages paged out\n", sum.v_swappgsout);
(void)printf("%9u vnode pager pageins\n", sum.v_vnodein);
(void)printf("%9u vnode pager pages paged in\n", sum.v_vnodepgsin);
(void)printf("%9u vnode pager pageouts\n", sum.v_vnodeout);
(void)printf("%9u vnode pager pages paged out\n", sum.v_vnodepgsout);
(void)printf("%9u page daemon wakeups\n", sum.v_pdwakeups);
(void)printf("%9u pages examined by the page daemon\n", sum.v_pdpages);
(void)printf("%9u pages reactivated\n", sum.v_reactivated);
(void)printf("%9u copy-on-write faults\n", sum.v_cow_faults);
(void)printf("%9u copy-on-write optimized faults\n", sum.v_cow_optim);
(void)printf("%9u zero fill pages zeroed\n", sum.v_zfod);
(void)printf("%9u zero fill pages prezeroed\n", sum.v_ozfod);
(void)printf("%9u intransit blocking page faults\n", sum.v_intrans);
(void)printf("%9u total VM faults taken\n", sum.v_vm_faults);
(void)printf("%9u pages affected by kernel thread creation\n", sum.v_kthreadpages);
(void)printf("%9u pages affected by fork()\n", sum.v_forkpages);
(void)printf("%9u pages affected by vfork()\n", sum.v_vforkpages);
(void)printf("%9u pages affected by rfork()\n", sum.v_rforkpages);
(void)printf("%9u pages freed\n", sum.v_tfree);
(void)printf("%9u pages freed by daemon\n", sum.v_dfree);
(void)printf("%9u pages freed by exiting processes\n", sum.v_pfree);
(void)printf("%9u pages active\n", sum.v_active_count);
(void)printf("%9u pages inactive\n", sum.v_inactive_count);
(void)printf("%9u pages in VM cache\n", sum.v_cache_count);
(void)printf("%9u pages wired down\n", sum.v_wire_count);
(void)printf("%9u pages free\n", sum.v_free_count);
(void)printf("%9u bytes per page\n", sum.v_page_size);
kread(X_NCHSTATS, &lnchstats, sizeof(lnchstats));
nchtotal = lnchstats.ncs_goodhits + lnchstats.ncs_neghits +
lnchstats.ncs_badhits + lnchstats.ncs_falsehits +
lnchstats.ncs_miss + lnchstats.ncs_long;
(void)printf("%9ld total name lookups\n", nchtotal);
(void)printf(
"%9s cache hits (%ld%% pos + %ld%% neg) system %ld%% per-directory\n",
"", PCT(lnchstats.ncs_goodhits, nchtotal),
PCT(lnchstats.ncs_neghits, nchtotal),
PCT(lnchstats.ncs_pass2, nchtotal));
(void)printf("%9s deletions %ld%%, falsehits %ld%%, toolong %ld%%\n", "",
PCT(lnchstats.ncs_badhits, nchtotal),
PCT(lnchstats.ncs_falsehits, nchtotal),
PCT(lnchstats.ncs_long, nchtotal));
}
void
doforkst()
{
kread(X_SUM, &sum, sizeof(sum));
(void)printf("%d forks, %d pages, average %.2f\n",
sum.v_forks, sum.v_forkpages,
sum.v_forks == 0 ? 0.0 :
(double)sum.v_forkpages / sum.v_forks);
(void)printf("%d vforks, %d pages, average %.2f\n",
sum.v_vforks, sum.v_vforkpages,
sum.v_vforks == 0 ? 0.0 :
(double)sum.v_vforkpages / sum.v_vforks);
(void)printf("%d rforks, %d pages, average %.2f\n",
sum.v_rforks, sum.v_rforkpages,
sum.v_rforks == 0 ? 0.0 :
(double)sum.v_rforkpages / sum.v_rforks);
}
static void
devstats()
{
int dn, state;
long double transfers_per_second;
long double busy_seconds;
long tmp;
for (state = 0; state < CPUSTATES; ++state) {
tmp = cur.cp_time[state];
cur.cp_time[state] -= last.cp_time[state];
last.cp_time[state] = tmp;
}
busy_seconds = cur.snap_time - last.snap_time;
for (dn = 0; dn < num_devices; dn++) {
int di;
if ((dev_select[dn].selected == 0)
|| (dev_select[dn].selected > maxshowdevs))
continue;
di = dev_select[dn].position;
if (devstat_compute_statistics(&cur.dinfo->devices[di],
&last.dinfo->devices[di], busy_seconds,
DSM_TRANSFERS_PER_SECOND, &transfers_per_second,
DSM_NONE) != 0)
errx(1, "%s", devstat_errbuf);
(void)printf("%3.0Lf ", transfers_per_second);
}
}
void
cpustats()
{
int state;
double lpct, total;
total = 0;
for (state = 0; state < CPUSTATES; ++state)
total += cur.cp_time[state];
if (total)
lpct = 100.0 / total;
else
lpct = 0.0;
(void)printf("%2.0f ", (cur.cp_time[CP_USER] +
cur.cp_time[CP_NICE]) * lpct);
(void)printf("%2.0f ", (cur.cp_time[CP_SYS] +
cur.cp_time[CP_INTR]) * lpct);
(void)printf("%2.0f", cur.cp_time[CP_IDLE] * lpct);
}
void
dointr()
{
u_long *intrcnt, uptime;
u_int64_t inttotal;
int nintr, inamlen;
char *intrname;
uptime = getuptime();
nintr = namelist[X_EINTRCNT].n_value - namelist[X_INTRCNT].n_value;
inamlen =
namelist[X_EINTRNAMES].n_value - namelist[X_INTRNAMES].n_value;
intrcnt = malloc((size_t)nintr);
intrname = malloc((size_t)inamlen);
if (intrcnt == NULL || intrname == NULL)
errx(1, "malloc");
kread(X_INTRCNT, intrcnt, (size_t)nintr);
kread(X_INTRNAMES, intrname, (size_t)inamlen);
(void)printf("%-14s %20s %10s\n", "interrupt", "total", "rate");
inttotal = 0;
nintr /= sizeof(long);
while (--nintr >= 0) {
if (*intrcnt)
(void)printf("%-14s %20lu %10lu\n", intrname,
*intrcnt, *intrcnt / uptime);
intrname += strlen(intrname) + 1;
inttotal += *intrcnt++;
}
(void)printf("%-14s %20llu %10llu\n", "Total", inttotal,
inttotal / (u_int64_t) uptime);
}
void
domem(void)
{
dosysctl("kern.malloc");
}
void
dozmem(void)
{
dosysctl("vm.zone");
}
void
dosysctl(char *name)
{
char *buf;
size_t bufsize;
buf = NULL;
bufsize = 1024;
for (;;) {
if ((buf = realloc(buf, bufsize)) == NULL)
err(1, "realloc()");
if (sysctlbyname(name, buf, &bufsize, 0, NULL) == 0)
break;
if (errno != ENOMEM)
err(1, "sysctl()");
bufsize *= 2;
}
buf[bufsize] = '\0'; /* play it safe */
(void)printf("%s\n\n", buf);
free(buf);
}
/*
* kread reads something from the kernel, given its nlist index.
*/
void
kread(nlx, addr, size)
int nlx;
void *addr;
size_t size;
{
char *sym;
if (namelist[nlx].n_type == 0 || namelist[nlx].n_value == 0) {
sym = namelist[nlx].n_name;
if (*sym == '_')
++sym;
errx(1, "symbol %s not defined", sym);
}
if (kvm_read(kd, namelist[nlx].n_value, addr, size) != (int)size) {
sym = namelist[nlx].n_name;
if (*sym == '_')
++sym;
errx(1, "%s: %s", sym, kvm_geterr(kd));
}
}
void
usage()
{
(void)fprintf(stderr, "%s%s",
"usage: vmstat [-imsz] [-c count] [-M core] [-N system] [-w wait]\n",
" [-n devs] [disks]\n");
exit(1);
}