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freebsd/lib/libkvm/kvm_getswapinfo.c
John Baldwin e8865caffb - Move 'struct swdevt' back into swap_pager.h and expose it to userland.
- Restore support for fetching swap information from crash dumps via
  kvm_get_swapinfo(3) to fix pstat -T/-s on crash dumps.

Reviewed by:	arch@, phk
MFC after:	1 week
2007-02-07 17:43:11 +00:00

278 lines
6.8 KiB
C

/*
* Copyright (c) 1999, Matthew Dillon. All Rights Reserved.
* Copyright (c) 2001, Thomas Moestl. 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.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR 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 AUTHOR 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("$FreeBSD$");
#include <sys/param.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/blist.h>
#include <sys/sysctl.h>
#include <vm/swap_pager.h>
#include <vm/vm_param.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <kvm.h>
#include <nlist.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include "kvm_private.h"
static struct nlist kvm_swap_nl[] = {
{ "_swtailq" }, /* list of swap devices and sizes */
{ "_dmmax" }, /* maximum size of a swap block */
{ NULL }
};
#define NL_SWTAILQ 0
#define NL_DMMAX 1
static int kvm_swap_nl_cached = 0;
static int unswdev; /* number of found swap dev's */
static int dmmax;
static int kvm_getswapinfo_kvm(kvm_t *, struct kvm_swap *, int, int);
static int kvm_getswapinfo_sysctl(kvm_t *, struct kvm_swap *, int, int);
static int nlist_init(kvm_t *);
static int getsysctl(kvm_t *, char *, void *, size_t);
#define KREAD(kd, addr, obj) \
(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
#define KGET(idx, var) \
KGET2(kvm_swap_nl[(idx)].n_value, var, kvm_swap_nl[(idx)].n_name)
#define KGET2(addr, var, msg) \
if (KREAD(kd, (u_long)(addr), (var))) { \
_kvm_err(kd, kd->program, "cannot read %s", msg); \
return (-1); \
}
#define GETSWDEVNAME(dev, str, flags) \
if (dev == NODEV) { \
strlcpy(str, "[NFS swap]", sizeof(str)); \
} else { \
snprintf( \
str, sizeof(str),"%s%s", \
((flags & SWIF_DEV_PREFIX) ? _PATH_DEV : ""), \
devname(dev, S_IFCHR) \
); \
}
int
kvm_getswapinfo(
kvm_t *kd,
struct kvm_swap *swap_ary,
int swap_max,
int flags
) {
/*
* clear cache
*/
if (kd == NULL) {
kvm_swap_nl_cached = 0;
return(0);
}
if (ISALIVE(kd)) {
return kvm_getswapinfo_sysctl(kd, swap_ary, swap_max, flags);
} else {
return kvm_getswapinfo_kvm(kd, swap_ary, swap_max, flags);
}
}
int
kvm_getswapinfo_kvm(
kvm_t *kd,
struct kvm_swap *swap_ary,
int swap_max,
int flags
) {
int i, ttl;
TAILQ_HEAD(, swdevt) swtailq;
struct swdevt *sp, swinfo;
struct kvm_swap tot;
if (!nlist_init(kd))
return (-1);
bzero(&tot, sizeof(tot));
KGET(NL_SWTAILQ, &swtailq);
sp = TAILQ_FIRST(&swtailq);
for (i = 0; sp != NULL; i++) {
KGET2(sp, &swinfo, "swinfo");
ttl = swinfo.sw_nblks - dmmax;
if (i < swap_max - 1) {
bzero(&swap_ary[i], sizeof(swap_ary[i]));
swap_ary[i].ksw_total = ttl;
swap_ary[i].ksw_used = swinfo.sw_used;
swap_ary[i].ksw_flags = swinfo.sw_flags;
GETSWDEVNAME(swinfo.sw_dev, swap_ary[i].ksw_devname,
flags);
}
tot.ksw_total += ttl;
tot.ksw_used += swinfo.sw_used;
sp = TAILQ_NEXT(&swinfo, sw_list);
}
if (i >= swap_max)
i = swap_max - 1;
if (i >= 0)
swap_ary[i] = tot;
return(i);
}
#define GETSYSCTL(kd, name, var) \
getsysctl(kd, name, &(var), sizeof(var))
/* The maximum MIB length for vm.swap_info and an additional device number */
#define SWI_MAXMIB 3
int
kvm_getswapinfo_sysctl(
kvm_t *kd,
struct kvm_swap *swap_ary,
int swap_max,
int flags
) {
int ti, ttl;
size_t mibi, len;
int soid[SWI_MAXMIB];
struct xswdev xsd;
struct kvm_swap tot;
if (!GETSYSCTL(kd, "vm.dmmax", dmmax))
return -1;
mibi = SWI_MAXMIB - 1;
if (sysctlnametomib("vm.swap_info", soid, &mibi) == -1) {
_kvm_err(kd, kd->program, "sysctlnametomib failed: %s",
strerror(errno));
return -1;
}
bzero(&tot, sizeof(tot));
for (unswdev = 0;; unswdev++) {
soid[mibi] = unswdev;
len = sizeof(xsd);
if (sysctl(soid, mibi + 1, &xsd, &len, NULL, 0) == -1) {
if (errno == ENOENT)
break;
_kvm_err(kd, kd->program, "cannot read sysctl: %s.",
strerror(errno));
return -1;
}
if (len != sizeof(xsd)) {
_kvm_err(kd, kd->program, "struct xswdev has unexpected "
"size; kernel and libkvm out of sync?");
return -1;
}
if (xsd.xsw_version != XSWDEV_VERSION) {
_kvm_err(kd, kd->program, "struct xswdev version "
"mismatch; kernel and libkvm out of sync?");
return -1;
}
ttl = xsd.xsw_nblks - dmmax;
if (unswdev < swap_max - 1) {
bzero(&swap_ary[unswdev], sizeof(swap_ary[unswdev]));
swap_ary[unswdev].ksw_total = ttl;
swap_ary[unswdev].ksw_used = xsd.xsw_used;
swap_ary[unswdev].ksw_flags = xsd.xsw_flags;
GETSWDEVNAME(xsd.xsw_dev, swap_ary[unswdev].ksw_devname,
flags);
}
tot.ksw_total += ttl;
tot.ksw_used += xsd.xsw_used;
}
ti = unswdev;
if (ti >= swap_max)
ti = swap_max - 1;
if (ti >= 0)
swap_ary[ti] = tot;
return(ti);
}
static int
nlist_init(kvm_t *kd)
{
TAILQ_HEAD(, swdevt) swtailq;
struct swdevt *sp, swinfo;
if (kvm_swap_nl_cached)
return (1);
if (kvm_nlist(kd, kvm_swap_nl) < 0)
return (0);
/* Required entries */
if (kvm_swap_nl[NL_SWTAILQ].n_value == 0) {
_kvm_err(kd, kd->program, "unable to find swtailq");
return (0);
}
if (kvm_swap_nl[NL_DMMAX].n_value == 0) {
_kvm_err(kd, kd->program, "unable to find dmmax");
return (0);
}
/* Get globals, type of swap */
KGET(NL_DMMAX, &dmmax);
kvm_swap_nl_cached = 1;
return (1);
}
static int
getsysctl (
kvm_t *kd,
char *name,
void *ptr,
size_t len
) {
size_t nlen = len;
if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
_kvm_err(kd, kd->program, "cannot read sysctl %s:%s", name,
strerror(errno));
return (0);
}
if (nlen != len) {
_kvm_err(kd, kd->program, "sysctl %s has unexpected size", name);
return (0);
}
return (1);
}