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;
 119         swblk_t ttl;
 120         TAILQ_HEAD(, swdevt) swtailq;
 121         struct swdevt *sp, swinfo;
 122         struct kvm_swap tot;
 123
 124         if (!kd->arch->ka_native(kd)) {
 125                 _kvm_err(kd, kd->program,
 126                     "cannot read swapinfo from non-native core");
 127                 return (-1);
 128         }
 129
 130         if (!nlist_init(kd))
 131                 return (-1);
 132
 133         bzero(&tot, sizeof(tot));
 134         KGET(NL_SWTAILQ, &swtailq);
 135         sp = TAILQ_FIRST(&swtailq);
 136         for (i = 0; sp != NULL; i++) {
 137                 KGET2(sp, &swinfo, "swinfo");
 138                 ttl = swinfo.sw_nblks - dmmax;
 139                 if (i < swap_max - 1) {
 140                         bzero(&swap_ary[i], sizeof(swap_ary[i]));
 141                         swap_ary[i].ksw_total = ttl;
 142                         swap_ary[i].ksw_used = swinfo.sw_used;
 143                         swap_ary[i].ksw_flags = swinfo.sw_flags;
 144                         GETSWDEVNAME(swinfo.sw_dev, swap_ary[i].ksw_devname,
 145                              flags);
 146                 }
 147                 tot.ksw_total += ttl;
 148                 tot.ksw_used += swinfo.sw_used;
 149                 sp = TAILQ_NEXT(&swinfo, sw_list);
 150         }
 151
 152         if (i >= swap_max)
 153                 i = swap_max - 1;
 154         if (i >= 0)
 155                 swap_ary[i] = tot;
 156
 157         return(i);
 158 }
 159
 160 #define GETSYSCTL(kd, name, var)                                        \
 161             getsysctl(kd, name, &(var), sizeof(var))
 162
 163 /* The maximum MIB length for vm.swap_info and an additional device number */
 164 #define SWI_MAXMIB      3
 165
 166 int
 167 kvm_getswapinfo_sysctl(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max,
 168     int flags)
 169 {
 170         int ti;
 171         swblk_t ttl;
 172         size_t mibi, len;
 173         int soid[SWI_MAXMIB];
 174         struct xswdev xsd;
 175         struct kvm_swap tot;
 176
 177         if (!GETSYSCTL(kd, "vm.dmmax", dmmax))
 178                 return -1;
 179
 180         mibi = SWI_MAXMIB - 1;
 181         if (sysctlnametomib("vm.swap_info", soid, &mibi) == -1) {
 182                 _kvm_err(kd, kd->program, "sysctlnametomib failed: %s",
 183                     strerror(errno));
 184                 return -1;
 185         }
 186         bzero(&tot, sizeof(tot));
 187         for (unswdev = 0;; unswdev++) {
 188                 soid[mibi] = unswdev;
 189                 len = sizeof(xsd);
 190                 if (sysctl(soid, mibi + 1, &xsd, &len, NULL, 0) == -1) {
 191                         if (errno == ENOENT)
 192                                 break;
 193                         _kvm_err(kd, kd->program, "cannot read sysctl: %s.",
 194                             strerror(errno));
 195                         return -1;
 196                 }
 197                 if (len != sizeof(xsd)) {
 198                         _kvm_err(kd, kd->program, "struct xswdev has unexpected "
 199                             "size;  kernel and libkvm out of sync?");
 200                         return -1;
 201                 }
 202                 if (xsd.xsw_version != XSWDEV_VERSION) {
 203                         _kvm_err(kd, kd->program, "struct xswdev version "
 204                             "mismatch; kernel and libkvm out of sync?");
 205                         return -1;
 206                 }
 207
 208                 ttl = xsd.xsw_nblks - dmmax;
 209                 if (unswdev < swap_max - 1) {
 210                         bzero(&swap_ary[unswdev], sizeof(swap_ary[unswdev]));
 211                         swap_ary[unswdev].ksw_total = ttl;
 212                         swap_ary[unswdev].ksw_used = xsd.xsw_used;
 213                         swap_ary[unswdev].ksw_flags = xsd.xsw_flags;
 214                         GETSWDEVNAME(xsd.xsw_dev, swap_ary[unswdev].ksw_devname,
 215                              flags);
 216                 }
 217                 tot.ksw_total += ttl;
 218                 tot.ksw_used += xsd.xsw_used;
 219         }
 220
 221         ti = unswdev;
 222         if (ti >= swap_max)
 223                 ti = swap_max - 1;
 224         if (ti >= 0)
 225                 swap_ary[ti] = tot;
 226
 227         return(ti);
 228 }
 229
 230 static int
 231 nlist_init(kvm_t *kd)
 232 {
 233
 234         if (kvm_swap_nl_cached)
 235                 return (1);
 236
 237         if (kvm_nlist(kd, kvm_swap_nl) < 0)
 238                 return (0);
 239
 240         /* Required entries */
 241         if (kvm_swap_nl[NL_SWTAILQ].n_value == 0) {
 242                 _kvm_err(kd, kd->program, "unable to find swtailq");
 243                 return (0);
 244         }
 245
 246         if (kvm_swap_nl[NL_DMMAX].n_value == 0) {
 247                 _kvm_err(kd, kd->program, "unable to find dmmax");
 248                 return (0);
 249         }
 250
 251         /* Get globals, type of swap */
 252         KGET(NL_DMMAX, &dmmax);
 253
 254         kvm_swap_nl_cached = 1;
 255         return (1);
 256 }
 257
 258 static int
 259 getsysctl(kvm_t *kd, const char *name, void *ptr, size_t len)
 260 {
 261         size_t nlen = len;
 262         if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
 263                 _kvm_err(kd, kd->program, "cannot read sysctl %s:%s", name,
 264                     strerror(errno));
 265                 return (0);
 266         }
 267         if (nlen != len) {
 268                 _kvm_err(kd, kd->program, "sysctl %s has unexpected size", name);
 269                 return (0);
 270         }
 271         return (1);
 272 }