1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1999, Matthew Dillon. All Rights Reserved.
5 * Copyright (c) 2001, Thomas Moestl. All Rights Reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD: stable/12/lib/libkvm/kvm_getswapinfo.c 358581 2020-03-03 15:07:48Z markj $");
31
32 #include <sys/param.h>
33 #include <sys/time.h>
34 #include <sys/stat.h>
35 #include <sys/blist.h>
36 #include <sys/queue.h>
37 #include <sys/sysctl.h>
38
39 #include <vm/swap_pager.h>
40 #include <vm/vm_param.h>
41
42 #include <err.h>
43 #include <errno.h>
44 #include <fcntl.h>
45 #include <kvm.h>
46 #include <nlist.h>
47 #include <paths.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <unistd.h>
52 #include <limits.h>
53
54 #include "kvm_private.h"
55
56 static struct nlist kvm_swap_nl[] = {
57 { .n_name = "_swtailq" }, /* list of swap devices and sizes */
58 { .n_name = "_dmmax" }, /* maximum size of a swap block */
59 { .n_name = NULL }
60 };
61
62 #define NL_SWTAILQ 0
63 #define NL_DMMAX 1
64
65 static int kvm_swap_nl_cached = 0;
66 static int unswdev; /* number of found swap dev's */
67 static int dmmax;
68
69 static int kvm_getswapinfo_kvm(kvm_t *, struct kvm_swap *, int, int);
70 static int kvm_getswapinfo_sysctl(kvm_t *, struct kvm_swap *, int, int);
71 static int nlist_init(kvm_t *);
72 static int getsysctl(kvm_t *, const char *, void *, size_t);
73
74 #define KREAD(kd, addr, obj) \
75 (kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
76 #define KGET(idx, var) \
77 KGET2(kvm_swap_nl[(idx)].n_value, var, kvm_swap_nl[(idx)].n_name)
78 #define KGET2(addr, var, msg) \
79 if (KREAD(kd, (u_long)(addr), (var))) { \
80 _kvm_err(kd, kd->program, "cannot read %s", msg); \
81 return (-1); \
82 }
83
84 #define GETSWDEVNAME(dev, str, flags) \
85 if (dev == NODEV) { \
86 strlcpy(str, "[NFS swap]", sizeof(str)); \
87 } else { \
88 snprintf( \
89 str, sizeof(str),"%s%s", \
90 ((flags & SWIF_DEV_PREFIX) ? _PATH_DEV : ""), \
91 devname(dev, S_IFCHR) \
92 ); \
93 }
94
95 int
kvm_getswapinfo(kvm_t * kd,struct kvm_swap * swap_ary,int swap_max,int flags)96 kvm_getswapinfo(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
97 {
98
99 /*
100 * clear cache
101 */
102 if (kd == NULL) {
103 kvm_swap_nl_cached = 0;
104 return(0);
105 }
106
107 if (ISALIVE(kd)) {
108 return kvm_getswapinfo_sysctl(kd, swap_ary, swap_max, flags);
109 } else {
110 return kvm_getswapinfo_kvm(kd, swap_ary, swap_max, flags);
111 }
112 }
113
114 int
kvm_getswapinfo_kvm(kvm_t * kd,struct kvm_swap * swap_ary,int swap_max,int flags)115 kvm_getswapinfo_kvm(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max,
116 int flags)
117 {
118 int i, ttl;
119 TAILQ_HEAD(, swdevt) swtailq;
120 struct swdevt *sp, swinfo;
121 struct kvm_swap tot;
122
123 if (!kd->arch->ka_native(kd)) {
124 _kvm_err(kd, kd->program,
125 "cannot read swapinfo from non-native core");
126 return (-1);
127 }
128
129 if (!nlist_init(kd))
130 return (-1);
131
132 bzero(&tot, sizeof(tot));
133 KGET(NL_SWTAILQ, &swtailq);
134 sp = TAILQ_FIRST(&swtailq);
135 for (i = 0; sp != NULL; i++) {
136 KGET2(sp, &swinfo, "swinfo");
137 ttl = swinfo.sw_nblks - dmmax;
138 if (i < swap_max - 1) {
139 bzero(&swap_ary[i], sizeof(swap_ary[i]));
140 swap_ary[i].ksw_total = ttl;
141 swap_ary[i].ksw_used = swinfo.sw_used;
142 swap_ary[i].ksw_flags = swinfo.sw_flags;
143 GETSWDEVNAME(swinfo.sw_dev, swap_ary[i].ksw_devname,
144 flags);
145 }
146 tot.ksw_total += ttl;
147 tot.ksw_used += swinfo.sw_used;
148 sp = TAILQ_NEXT(&swinfo, sw_list);
149 }
150
151 if (i >= swap_max)
152 i = swap_max - 1;
153 if (i >= 0)
154 swap_ary[i] = tot;
155
156 return(i);
157 }
158
159 #define GETSYSCTL(kd, name, var) \
160 getsysctl(kd, name, &(var), sizeof(var))
161
162 /* The maximum MIB length for vm.swap_info and an additional device number */
163 #define SWI_MAXMIB 3
164
165 int
kvm_getswapinfo_sysctl(kvm_t * kd,struct kvm_swap * swap_ary,int swap_max,int flags)166 kvm_getswapinfo_sysctl(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max,
167 int flags)
168 {
169 int ti, ttl;
170 size_t mibi, len;
171 int soid[SWI_MAXMIB];
172 struct xswdev xsd;
173 struct kvm_swap tot;
174
175 if (!GETSYSCTL(kd, "vm.dmmax", dmmax))
176 return -1;
177
178 mibi = SWI_MAXMIB - 1;
179 if (sysctlnametomib("vm.swap_info", soid, &mibi) == -1) {
180 _kvm_err(kd, kd->program, "sysctlnametomib failed: %s",
181 strerror(errno));
182 return -1;
183 }
184 bzero(&tot, sizeof(tot));
185 for (unswdev = 0;; unswdev++) {
186 soid[mibi] = unswdev;
187 len = sizeof(xsd);
188 if (sysctl(soid, mibi + 1, &xsd, &len, NULL, 0) == -1) {
189 if (errno == ENOENT)
190 break;
191 _kvm_err(kd, kd->program, "cannot read sysctl: %s.",
192 strerror(errno));
193 return -1;
194 }
195 if (len != sizeof(xsd)) {
196 _kvm_err(kd, kd->program, "struct xswdev has unexpected "
197 "size; kernel and libkvm out of sync?");
198 return -1;
199 }
200 if (xsd.xsw_version != XSWDEV_VERSION) {
201 _kvm_err(kd, kd->program, "struct xswdev version "
202 "mismatch; kernel and libkvm out of sync?");
203 return -1;
204 }
205
206 ttl = xsd.xsw_nblks - dmmax;
207 if (unswdev < swap_max - 1) {
208 bzero(&swap_ary[unswdev], sizeof(swap_ary[unswdev]));
209 swap_ary[unswdev].ksw_total = ttl;
210 swap_ary[unswdev].ksw_used = xsd.xsw_used;
211 swap_ary[unswdev].ksw_flags = xsd.xsw_flags;
212 GETSWDEVNAME(xsd.xsw_dev, swap_ary[unswdev].ksw_devname,
213 flags);
214 }
215 tot.ksw_total += ttl;
216 tot.ksw_used += xsd.xsw_used;
217 }
218
219 ti = unswdev;
220 if (ti >= swap_max)
221 ti = swap_max - 1;
222 if (ti >= 0)
223 swap_ary[ti] = tot;
224
225 return(ti);
226 }
227
228 static int
nlist_init(kvm_t * kd)229 nlist_init(kvm_t *kd)
230 {
231
232 if (kvm_swap_nl_cached)
233 return (1);
234
235 if (kvm_nlist(kd, kvm_swap_nl) < 0)
236 return (0);
237
238 /* Required entries */
239 if (kvm_swap_nl[NL_SWTAILQ].n_value == 0) {
240 _kvm_err(kd, kd->program, "unable to find swtailq");
241 return (0);
242 }
243
244 if (kvm_swap_nl[NL_DMMAX].n_value == 0) {
245 _kvm_err(kd, kd->program, "unable to find dmmax");
246 return (0);
247 }
248
249 /* Get globals, type of swap */
250 KGET(NL_DMMAX, &dmmax);
251
252 kvm_swap_nl_cached = 1;
253 return (1);
254 }
255
256 static int
getsysctl(kvm_t * kd,const char * name,void * ptr,size_t len)257 getsysctl(kvm_t *kd, const char *name, void *ptr, size_t len)
258 {
259 size_t nlen = len;
260 if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
261 _kvm_err(kd, kd->program, "cannot read sysctl %s:%s", name,
262 strerror(errno));
263 return (0);
264 }
265 if (nlen != len) {
266 _kvm_err(kd, kd->program, "sysctl %s has unexpected size", name);
267 return (0);
268 }
269 return (1);
270 }
271