kvm_getswapinfo.c revision 132935 
1/*
2 * Copyright (c) 1999, Matthew Dillon.  All Rights Reserved.
3 * Copyright (c) 2001, Thomas Moestl.  All Rights Reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/lib/libkvm/kvm_getswapinfo.c 132935 2004-07-31 18:49:53Z imp $");
29
30#include <sys/param.h>
31#include <sys/time.h>
32#include <sys/stat.h>
33#include <sys/blist.h>
34#include <sys/sysctl.h>
35
36#include <vm/vm_param.h>
37
38#include <err.h>
39#include <errno.h>
40#include <fcntl.h>
41#include <kvm.h>
42#include <nlist.h>
43#include <paths.h>
44#include <stdio.h>
45#include <stdlib.h>
46#include <string.h>
47#include <unistd.h>
48#include <limits.h>
49
50#include "kvm_private.h"
51
52#define NL_SWAPBLIST	0
53#define NL_SWDEVT	1
54#define NL_NSWDEV	2
55#define NL_DMMAX	3
56
57static int kvm_swap_nl_cached = 0;
58static int unswdev;  /* number of found swap dev's */
59static int dmmax;
60
61static int  kvm_getswapinfo_sysctl(kvm_t *, struct kvm_swap *, int, int);
62static int  getsysctl(kvm_t *, char *, void *, size_t);
63
64#define GETSWDEVNAME(dev, str, flags)					\
65	if (dev == NODEV) {						\
66		strlcpy(str, "[NFS swap]", sizeof(str));		\
67	} else {							\
68		snprintf(						\
69		    str, sizeof(str),"%s%s",				\
70		    ((flags & SWIF_DEV_PREFIX) ? _PATH_DEV : ""),	\
71		    devname(dev, S_IFCHR)				\
72		);							\
73	}
74
75int
76kvm_getswapinfo(
77	kvm_t *kd,
78	struct kvm_swap *swap_ary,
79	int swap_max,
80	int flags
81) {
82
83	/*
84	 * clear cache
85	 */
86	if (kd == NULL) {
87		kvm_swap_nl_cached = 0;
88		return(0);
89	}
90
91	if (ISALIVE(kd)) {
92		return kvm_getswapinfo_sysctl(kd, swap_ary, swap_max, flags);
93	} else {
94		return -1;
95	}
96}
97
98#define	GETSYSCTL(kd, name, var)					\
99	    getsysctl(kd, name, &(var), sizeof(var))
100
101/* The maximum MIB length for vm.swap_info and an additional device number */
102#define	SWI_MAXMIB	3
103
104int
105kvm_getswapinfo_sysctl(
106	kvm_t *kd,
107	struct kvm_swap *swap_ary,
108	int swap_max,
109	int flags
110) {
111	int ti, ttl;
112	size_t mibi, len;
113	int soid[SWI_MAXMIB];
114	struct xswdev xsd;
115	struct kvm_swap tot;
116
117	if (!GETSYSCTL(kd, "vm.dmmax", dmmax))
118		return -1;
119
120	mibi = SWI_MAXMIB - 1;
121	if (sysctlnametomib("vm.swap_info", soid, &mibi) == -1) {
122		_kvm_err(kd, kd->program, "sysctlnametomib failed: %s",
123		    strerror(errno));
124		return -1;
125	}
126	bzero(&tot, sizeof(tot));
127	for (unswdev = 0;; unswdev++) {
128		soid[mibi] = unswdev;
129		len = sizeof(xsd);
130		if (sysctl(soid, mibi + 1, &xsd, &len, NULL, 0) == -1) {
131			if (errno == ENOENT)
132				break;
133			_kvm_err(kd, kd->program, "cannot read sysctl: %s.",
134			    strerror(errno));
135			return -1;
136		}
137		if (len != sizeof(xsd)) {
138			_kvm_err(kd, kd->program, "struct xswdev has unexpected "
139			    "size;  kernel and libkvm out of sync?");
140			return -1;
141		}
142		if (xsd.xsw_version != XSWDEV_VERSION) {
143			_kvm_err(kd, kd->program, "struct xswdev version "
144			    "mismatch; kernel and libkvm out of sync?");
145			return -1;
146		}
147
148		ttl = xsd.xsw_nblks - dmmax;
149		if (unswdev < swap_max - 1) {
150			bzero(&swap_ary[unswdev], sizeof(swap_ary[unswdev]));
151			swap_ary[unswdev].ksw_total = ttl;
152			swap_ary[unswdev].ksw_used = xsd.xsw_used;
153			swap_ary[unswdev].ksw_flags = xsd.xsw_flags;
154			GETSWDEVNAME(xsd.xsw_dev, swap_ary[unswdev].ksw_devname,
155			     flags);
156		}
157		tot.ksw_total += ttl;
158		tot.ksw_used += xsd.xsw_used;
159	}
160
161	ti = unswdev;
162	if (ti >= swap_max)
163		ti = swap_max - 1;
164	if (ti >= 0)
165		swap_ary[ti] = tot;
166
167        return(ti);
168}
169
170static int
171getsysctl (
172	kvm_t *kd,
173	char *name,
174	void *ptr,
175	size_t len
176) {
177	size_t nlen = len;
178	if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
179		_kvm_err(kd, kd->program, "cannot read sysctl %s:%s", name,
180		    strerror(errno));
181		return (0);
182	}
183	if (nlen != len) {
184		_kvm_err(kd, kd->program, "sysctl %s has unexpected size", name);
185		return (0);
186	}
187	return (1);
188}
189