lib/libkvm/kvm_getswapinfo.c

   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("$FreeBSD$");
  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
  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
 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
 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
 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
 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 }