kvm_getswapinfo.c revision 330897
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/11/lib/libkvm/kvm_getswapinfo.c 330897 2018-03-14 03:19:51Z eadler $"); 31 32#include <sys/param.h> 33#include <sys/time.h> 34#include <sys/stat.h> 35#include <sys/blist.h> 36#include <sys/sysctl.h> 37 38#include <vm/swap_pager.h> 39#include <vm/vm_param.h> 40 41#include <err.h> 42#include <errno.h> 43#include <fcntl.h> 44#include <kvm.h> 45#include <nlist.h> 46#include <paths.h> 47#include <stdio.h> 48#include <stdlib.h> 49#include <string.h> 50#include <unistd.h> 51#include <limits.h> 52 53#include "kvm_private.h" 54 55static struct nlist kvm_swap_nl[] = { 56 { .n_name = "_swtailq" }, /* list of swap devices and sizes */ 57 { .n_name = "_dmmax" }, /* maximum size of a swap block */ 58 { .n_name = NULL } 59}; 60 61#define NL_SWTAILQ 0 62#define NL_DMMAX 1 63 64static int kvm_swap_nl_cached = 0; 65static int unswdev; /* number of found swap dev's */ 66static int dmmax; 67 68static int kvm_getswapinfo_kvm(kvm_t *, struct kvm_swap *, int, int); 69static int kvm_getswapinfo_sysctl(kvm_t *, struct kvm_swap *, int, int); 70static int nlist_init(kvm_t *); 71static int getsysctl(kvm_t *, const char *, void *, size_t); 72 73#define KREAD(kd, addr, obj) \ 74 (kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj)) 75#define KGET(idx, var) \ 76 KGET2(kvm_swap_nl[(idx)].n_value, var, kvm_swap_nl[(idx)].n_name) 77#define KGET2(addr, var, msg) \ 78 if (KREAD(kd, (u_long)(addr), (var))) { \ 79 _kvm_err(kd, kd->program, "cannot read %s", msg); \ 80 return (-1); \ 81 } 82 83#define GETSWDEVNAME(dev, str, flags) \ 84 if (dev == NODEV) { \ 85 strlcpy(str, "[NFS swap]", sizeof(str)); \ 86 } else { \ 87 snprintf( \ 88 str, sizeof(str),"%s%s", \ 89 ((flags & SWIF_DEV_PREFIX) ? _PATH_DEV : ""), \ 90 devname(dev, S_IFCHR) \ 91 ); \ 92 } 93 94int 95kvm_getswapinfo(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags) 96{ 97 98 /* 99 * clear cache 100 */ 101 if (kd == NULL) { 102 kvm_swap_nl_cached = 0; 103 return(0); 104 } 105 106 if (ISALIVE(kd)) { 107 return kvm_getswapinfo_sysctl(kd, swap_ary, swap_max, flags); 108 } else { 109 return kvm_getswapinfo_kvm(kd, swap_ary, swap_max, flags); 110 } 111} 112 113int 114kvm_getswapinfo_kvm(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, 115 int flags) 116{ 117 int i; 118 swblk_t 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 165int 166kvm_getswapinfo_sysctl(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, 167 int flags) 168{ 169 int ti; 170 swblk_t ttl; 171 size_t mibi, len; 172 int soid[SWI_MAXMIB]; 173 struct xswdev xsd; 174 struct kvm_swap tot; 175 176 if (!GETSYSCTL(kd, "vm.dmmax", dmmax)) 177 return -1; 178 179 mibi = SWI_MAXMIB - 1; 180 if (sysctlnametomib("vm.swap_info", soid, &mibi) == -1) { 181 _kvm_err(kd, kd->program, "sysctlnametomib failed: %s", 182 strerror(errno)); 183 return -1; 184 } 185 bzero(&tot, sizeof(tot)); 186 for (unswdev = 0;; unswdev++) { 187 soid[mibi] = unswdev; 188 len = sizeof(xsd); 189 if (sysctl(soid, mibi + 1, &xsd, &len, NULL, 0) == -1) { 190 if (errno == ENOENT) 191 break; 192 _kvm_err(kd, kd->program, "cannot read sysctl: %s.", 193 strerror(errno)); 194 return -1; 195 } 196 if (len != sizeof(xsd)) { 197 _kvm_err(kd, kd->program, "struct xswdev has unexpected " 198 "size; kernel and libkvm out of sync?"); 199 return -1; 200 } 201 if (xsd.xsw_version != XSWDEV_VERSION) { 202 _kvm_err(kd, kd->program, "struct xswdev version " 203 "mismatch; kernel and libkvm out of sync?"); 204 return -1; 205 } 206 207 ttl = xsd.xsw_nblks - dmmax; 208 if (unswdev < swap_max - 1) { 209 bzero(&swap_ary[unswdev], sizeof(swap_ary[unswdev])); 210 swap_ary[unswdev].ksw_total = ttl; 211 swap_ary[unswdev].ksw_used = xsd.xsw_used; 212 swap_ary[unswdev].ksw_flags = xsd.xsw_flags; 213 GETSWDEVNAME(xsd.xsw_dev, swap_ary[unswdev].ksw_devname, 214 flags); 215 } 216 tot.ksw_total += ttl; 217 tot.ksw_used += xsd.xsw_used; 218 } 219 220 ti = unswdev; 221 if (ti >= swap_max) 222 ti = swap_max - 1; 223 if (ti >= 0) 224 swap_ary[ti] = tot; 225 226 return(ti); 227} 228 229static int 230nlist_init(kvm_t *kd) 231{ 232 233 if (kvm_swap_nl_cached) 234 return (1); 235 236 if (kvm_nlist(kd, kvm_swap_nl) < 0) 237 return (0); 238 239 /* Required entries */ 240 if (kvm_swap_nl[NL_SWTAILQ].n_value == 0) { 241 _kvm_err(kd, kd->program, "unable to find swtailq"); 242 return (0); 243 } 244 245 if (kvm_swap_nl[NL_DMMAX].n_value == 0) { 246 _kvm_err(kd, kd->program, "unable to find dmmax"); 247 return (0); 248 } 249 250 /* Get globals, type of swap */ 251 KGET(NL_DMMAX, &dmmax); 252 253 kvm_swap_nl_cached = 1; 254 return (1); 255} 256 257static int 258getsysctl(kvm_t *kd, const char *name, void *ptr, size_t len) 259{ 260 size_t nlen = len; 261 if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) { 262 _kvm_err(kd, kd->program, "cannot read sysctl %s:%s", name, 263 strerror(errno)); 264 return (0); 265 } 266 if (nlen != len) { 267 _kvm_err(kd, kd->program, "sysctl %s has unexpected size", name); 268 return (0); 269 } 270 return (1); 271} 272