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/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
  55 static 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
  64 static int kvm_swap_nl_cached = 0;
  65 static int unswdev;  /* number of found swap dev's */
  66 static int dmmax;
  67
  68 static int  kvm_getswapinfo_kvm(kvm_t *, struct kvm_swap *, int, int);
  69 static int  kvm_getswapinfo_sysctl(kvm_t *, struct kvm_swap *, int, int);
  70 static int  nlist_init(kvm_t *);
  71 static 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
  94 int
  95 kvm_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
 113 int
 114 kvm_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
 165 int
 166 kvm_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
 229 static int
 230 nlist_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
 257 static int
 258 getsysctl(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 }