lib/libkvm/kvm_getswapinfo.c

   1 /*
   2  * Copyright (c) 1999, Matthew Dillon.  All Rights Reserved.
   3  * Copyright (c) 2001, Thomas Moestl.  All Rights Reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/param.h>
  31 #include <sys/time.h>
  32 #include <sys/stat.h>
  33 #include <sys/blist.h>
  34 #include <sys/sysctl.h>
  35
  36 #include <vm/swap_pager.h>
  37 #include <vm/vm_param.h>
  38
  39 #include <err.h>
  40 #include <errno.h>
  41 #include <fcntl.h>
  42 #include <kvm.h>
  43 #include <nlist.h>
  44 #include <paths.h>
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48 #include <unistd.h>
  49 #include <limits.h>
  50
  51 #include "kvm_private.h"
  52
  53 static struct nlist kvm_swap_nl[] = {
  54         { "_swtailq" },         /* list of swap devices and sizes */
  55         { "_dmmax" },           /* maximum size of a swap block */
  56         { NULL }
  57 };
  58
  59 #define NL_SWTAILQ      0
  60 #define NL_DMMAX        1
  61
  62 static int kvm_swap_nl_cached = 0;
  63 static int unswdev;  /* number of found swap dev's */
  64 static int dmmax;
  65
  66 static int  kvm_getswapinfo_kvm(kvm_t *, struct kvm_swap *, int, int);
  67 static int  kvm_getswapinfo_sysctl(kvm_t *, struct kvm_swap *, int, int);
  68 static int  nlist_init(kvm_t *);
  69 static int  getsysctl(kvm_t *, char *, void *, size_t);
  70
  71 #define KREAD(kd, addr, obj) \
  72         (kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
  73 #define KGET(idx, var)                                                  \
  74         KGET2(kvm_swap_nl[(idx)].n_value, var, kvm_swap_nl[(idx)].n_name)
  75 #define KGET2(addr, var, msg)                                           \
  76         if (KREAD(kd, (u_long)(addr), (var))) {                         \
  77                 _kvm_err(kd, kd->program, "cannot read %s", msg);       \
  78                 return (-1);                                            \
  79         }
  80
  81 #define GETSWDEVNAME(dev, str, flags)                                   \
  82         if (dev == NODEV) {                                             \
  83                 strlcpy(str, "[NFS swap]", sizeof(str));                \
  84         } else {                                                        \
  85                 snprintf(                                               \
  86                     str, sizeof(str),"%s%s",                            \
  87                     ((flags & SWIF_DEV_PREFIX) ? _PATH_DEV : ""),       \
  88                     devname(dev, S_IFCHR)                               \
  89                 );                                                      \
  90         }
  91
  92 int
  93 kvm_getswapinfo(
  94         kvm_t *kd,
  95         struct kvm_swap *swap_ary,
  96         int swap_max,
  97         int flags
  98 ) {
  99
 100         /*
 101          * clear cache
 102          */
 103         if (kd == NULL) {
 104                 kvm_swap_nl_cached = 0;
 105                 return(0);
 106         }
 107
 108         if (ISALIVE(kd)) {
 109                 return kvm_getswapinfo_sysctl(kd, swap_ary, swap_max, flags);
 110         } else {
 111                 return kvm_getswapinfo_kvm(kd, swap_ary, swap_max, flags);
 112         }
 113 }
 114
 115 int
 116 kvm_getswapinfo_kvm(
 117         kvm_t *kd,
 118         struct kvm_swap *swap_ary,
 119         int swap_max,
 120         int flags
 121 ) {
 122         int i, ttl;
 123         TAILQ_HEAD(, swdevt) swtailq;
 124         struct swdevt *sp, swinfo;
 125         struct kvm_swap tot;
 126
 127         if (!nlist_init(kd))
 128                 return (-1);
 129
 130         bzero(&tot, sizeof(tot));
 131         KGET(NL_SWTAILQ, &swtailq);
 132         sp = TAILQ_FIRST(&swtailq);
 133         for (i = 0; sp != NULL; i++) {
 134                 KGET2(sp, &swinfo, "swinfo");
 135                 ttl = swinfo.sw_nblks - dmmax;
 136                 if (i < swap_max - 1) {
 137                         bzero(&swap_ary[i], sizeof(swap_ary[i]));
 138                         swap_ary[i].ksw_total = ttl;
 139                         swap_ary[i].ksw_used = swinfo.sw_used;
 140                         swap_ary[i].ksw_flags = swinfo.sw_flags;
 141                         GETSWDEVNAME(swinfo.sw_dev, swap_ary[i].ksw_devname,
 142                              flags);
 143                 }
 144                 tot.ksw_total += ttl;
 145                 tot.ksw_used += swinfo.sw_used;
 146                 sp = TAILQ_NEXT(&swinfo, sw_list);
 147         }
 148
 149         if (i >= swap_max)
 150                 i = swap_max - 1;
 151         if (i >= 0)
 152                 swap_ary[i] = tot;
 153
 154         return(i);
 155 }
 156
 157 #define GETSYSCTL(kd, name, var)                                        \
 158             getsysctl(kd, name, &(var), sizeof(var))
 159
 160 /* The maximum MIB length for vm.swap_info and an additional device number */
 161 #define SWI_MAXMIB      3
 162
 163 int
 164 kvm_getswapinfo_sysctl(
 165         kvm_t *kd,
 166         struct kvm_swap *swap_ary,
 167         int swap_max,
 168         int flags
 169 ) {
 170         int ti, 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         TAILQ_HEAD(, swdevt) swtailq;
 233         struct swdevt *sp, swinfo;
 234
 235         if (kvm_swap_nl_cached)
 236                 return (1);
 237
 238         if (kvm_nlist(kd, kvm_swap_nl) < 0)
 239                 return (0);
 240
 241         /* Required entries */
 242         if (kvm_swap_nl[NL_SWTAILQ].n_value == 0) {
 243                 _kvm_err(kd, kd->program, "unable to find swtailq");
 244                 return (0);
 245         }
 246
 247         if (kvm_swap_nl[NL_DMMAX].n_value == 0) {
 248                 _kvm_err(kd, kd->program, "unable to find dmmax");
 249                 return (0);
 250         }
 251
 252         /* Get globals, type of swap */
 253         KGET(NL_DMMAX, &dmmax);
 254
 255         kvm_swap_nl_cached = 1;
 256         return (1);
 257 }
 258
 259 static int
 260 getsysctl (
 261         kvm_t *kd,
 262         char *name,
 263         void *ptr,
 264         size_t len
 265 ) {
 266         size_t nlen = len;
 267         if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
 268                 _kvm_err(kd, kd->program, "cannot read sysctl %s:%s", name,
 269                     strerror(errno));
 270                 return (0);
 271         }
 272         if (nlen != len) {
 273                 _kvm_err(kd, kd->program, "sysctl %s has unexpected size", name);
 274                 return (0);
 275         }
 276         return (1);
 277 }