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NetBSD/usr.bin/vmstat/dkstats.c

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/* $NetBSD: dkstats.c,v 1.6 1998/08/10 03:11:08 perry Exp $ */
/*
* Copyright (c) 1996 John M. Vinopal
* 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 for the NetBSD Project
* by John M. Vinopal.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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/types.h>
#include <sys/dkstat.h>
#include <sys/time.h>
#include <sys/disk.h>
#include <err.h>
#include <fcntl.h>
#include <kvm.h>
#include <limits.h>
#include <nlist.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "dkstats.h"
static struct nlist namelist[] = {
#define X_TK_NIN 0
{ "_tk_nin" }, /* tty characters in */
#define X_TK_NOUT 1
{ "_tk_nout" }, /* tty characters out */
#define X_CP_TIME 2
{ "_cp_time" }, /* system timer ticks */
#define X_HZ 3
{ "_hz" }, /* ticks per second */
#define X_STATHZ 4
{ "_stathz" },
#define X_DISK_COUNT 5
{ "_disk_count" }, /* number of disks */
#define X_DISKLIST 6
{ "_disklist" }, /* TAILQ of disks */
{ NULL },
};
/* Structures to hold the statistics. */
struct _disk cur, last;
/* Kernel pointers: nlistf and memf defined in calling program. */
static kvm_t *kd = NULL;
extern char *nlistf;
extern char *memf;
/* Pointer to list of disks. */
static struct disk *dk_drivehead = NULL;
/* Backward compatibility references. */
int dk_ndrive = 0;
int *dk_select;
char **dr_name;
#define KVM_ERROR(_string) { \
warnx((_string)); \
errx(1, kvm_geterr(kd)); \
}
/*
* Dereference the namelist pointer `v' and fill in the local copy
* 'p' which is of size 's'.
*/
#define deref_nl(v, p, s) deref_kptr((void *)namelist[(v)].n_value, (p), (s));
/* Missing from <sys/time.h> */
#define timerset(tvp, uvp) ((uvp)->tv_sec = (tvp)->tv_sec); \
((uvp)->tv_usec = (tvp)->tv_usec)
void dkswap __P((void));
void dkreadstats __P((void));
int dkinit __P((int, gid_t));
static void deref_kptr __P((void *, void *, size_t));
/*
* Take the delta between the present values and the last recorded
* values, storing the present values in the 'last' structure, and
* the delta values in the 'cur' structure.
*/
void
dkswap()
{
u_int64_t tmp;
int i;
#define SWAP(fld) tmp = cur.fld; \
cur.fld -= last.fld; \
last.fld = tmp
for (i = 0; i < dk_ndrive; i++) {
struct timeval tmp_timer;
if (!cur.dk_select[i])
continue;
/* Delta Values. */
SWAP(dk_xfer[i]);
SWAP(dk_seek[i]);
SWAP(dk_bytes[i]);
/* Delta Time. */
timerclear(&tmp_timer);
timerset(&(cur.dk_time[i]), &tmp_timer);
timersub(&tmp_timer, &(last.dk_time[i]), &(cur.dk_time[i]));
timerclear(&(last.dk_time[i]));
timerset(&tmp_timer, &(last.dk_time[i]));
}
for (i = 0; i < CPUSTATES; i++) {
SWAP(cp_time[i]);
}
SWAP(tk_nin);
SWAP(tk_nout);
#undef SWAP
}
/*
* Read the disk statistics for each disk in the disk list.
* Also collect statistics for tty i/o and cpu ticks.
*/
void
dkreadstats()
{
struct disk cur_disk, *p;
int i;
p = dk_drivehead;
for (i = 0; i < dk_ndrive; i++) {
deref_kptr(p, &cur_disk, sizeof(cur_disk));
cur.dk_xfer[i] = cur_disk.dk_xfer;
cur.dk_seek[i] = cur_disk.dk_seek;
cur.dk_bytes[i] = cur_disk.dk_bytes;
timerset(&(cur_disk.dk_time), &(cur.dk_time[i]));
p = cur_disk.dk_link.tqe_next;
}
deref_nl(X_CP_TIME, cur.cp_time, sizeof(cur.cp_time));
deref_nl(X_TK_NIN, &cur.tk_nin, sizeof(cur.tk_nin));
deref_nl(X_TK_NOUT, &cur.tk_nout, sizeof(cur.tk_nout));
}
/*
* Perform all of the initialization and memory allocation needed to
* track disk statistics.
*/
int
dkinit(select, egid)
int select;
gid_t egid;
{
gid_t oldgid;
struct disklist_head disk_head;
struct disk cur_disk, *p;
char errbuf[_POSIX2_LINE_MAX];
static int once = 0;
extern int hz;
int i;
if (once)
return (1);
/* assume privs for kvm access */
oldgid = getegid();
(void)setegid(egid);
/* Open the kernel. */
if ((kd = kvm_openfiles(nlistf, memf, NULL, O_RDONLY, errbuf)) == NULL)
errx(1, "kvm_openfiles: %s", errbuf);
/* we are finished with privs now */
(void)setegid(oldgid);
/* Obtain the namelist symbols from the kernel. */
if (kvm_nlist(kd, namelist))
KVM_ERROR("kvm_nlist failed to read symbols.");
/* Get the number of attached drives. */
deref_nl(X_DISK_COUNT, &dk_ndrive, sizeof(dk_ndrive));
if (dk_ndrive < 0)
errx(1, "invalid _disk_count %d.", dk_ndrive);
else if (dk_ndrive == 0) {
warnx("No drives attached.");
}
else {
/* Get a pointer to the first disk. */
deref_nl(X_DISKLIST, &disk_head, sizeof(disk_head));
dk_drivehead = disk_head.tqh_first;
}
/* Get ticks per second. */
deref_nl(X_STATHZ, &hz, sizeof(hz));
if (!hz)
deref_nl(X_HZ, &hz, sizeof(hz));
/* allocate space for the statistics */
cur.dk_time = calloc(dk_ndrive, sizeof(struct timeval));
cur.dk_xfer = calloc(dk_ndrive, sizeof(u_int64_t));
cur.dk_seek = calloc(dk_ndrive, sizeof(u_int64_t));
cur.dk_bytes = calloc(dk_ndrive, sizeof(u_int64_t));
last.dk_time = calloc(dk_ndrive, sizeof(struct timeval));
last.dk_xfer = calloc(dk_ndrive, sizeof(u_int64_t));
last.dk_seek = calloc(dk_ndrive, sizeof(u_int64_t));
last.dk_bytes = calloc(dk_ndrive, sizeof(u_int64_t));
cur.dk_select = calloc(dk_ndrive, sizeof(int));
cur.dk_name = calloc(dk_ndrive, sizeof(char *));
if (!cur.dk_time || !cur.dk_xfer || !cur.dk_seek || !cur.dk_bytes
|| !last.dk_time || !last.dk_xfer || !last.dk_seek || !last.dk_bytes
|| !cur.dk_select || !cur.dk_name)
errx(1, "Memory allocation failure.");
/* Set up the compatibility interfaces. */
dk_select = cur.dk_select;
dr_name = cur.dk_name;
/* Read the disk names and set intial selection. */
p = dk_drivehead;
for (i = 0; i < dk_ndrive; i++) {
char buf[10];
deref_kptr(p, &cur_disk, sizeof(cur_disk));
deref_kptr(cur_disk.dk_name, buf, sizeof(buf));
cur.dk_name[i] = strdup(buf);
cur.dk_select[i] = select;
p = cur_disk.dk_link.tqe_next;
}
/* Never do this initalization again. */
once = 1;
return(1);
}
/*
* Dereference the kernel pointer `kptr' and fill in the local copy
* pointed to by `ptr'. The storage space must be pre-allocated,
* and the size of the copy passed in `len'.
*/
static void
deref_kptr(kptr, ptr, len)
void *kptr, *ptr;
size_t len;
{
char buf[128];
if (kvm_read(kd, (u_long)kptr, (char *)ptr, len) != len) {
memset(buf, 0, sizeof(buf));
snprintf(buf, sizeof buf, "can't dereference kptr 0x%lx",
(u_long)kptr);
KVM_ERROR(buf);
}
}
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