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         { .n_name = "_swtailq" },       /* list of swap devices and sizes */
  55         { .n_name = "_dmmax" },         /* maximum size of a swap block */
  56         { .n_name = 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 *, const 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(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
  94 {
  95
  96         /*
  97          * clear cache
  98          */
  99         if (kd == NULL) {
 100                 kvm_swap_nl_cached = 0;
 101                 return(0);
 102         }
 103
 104         if (ISALIVE(kd)) {
 105                 return kvm_getswapinfo_sysctl(kd, swap_ary, swap_max, flags);
 106         } else {
 107                 return kvm_getswapinfo_kvm(kd, swap_ary, swap_max, flags);
 108         }
 109 }
 110
 111 int
 112 kvm_getswapinfo_kvm(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max,
 113     int flags)
 114 {
 115         int i, ttl;
 116         TAILQ_HEAD(, swdevt) swtailq;
 117         struct swdevt *sp, swinfo;
 118         struct kvm_swap tot;
 119
 120         if (!nlist_init(kd))
 121                 return (-1);
 122
 123         bzero(&tot, sizeof(tot));
 124         KGET(NL_SWTAILQ, &swtailq);
 125         sp = TAILQ_FIRST(&swtailq);
 126         for (i = 0; sp != NULL; i++) {
 127                 KGET2(sp, &swinfo, "swinfo");
 128                 ttl = swinfo.sw_nblks - dmmax;
 129                 if (i < swap_max - 1) {
 130                         bzero(&swap_ary[i], sizeof(swap_ary[i]));
 131                         swap_ary[i].ksw_total = ttl;
 132                         swap_ary[i].ksw_used = swinfo.sw_used;
 133                         swap_ary[i].ksw_flags = swinfo.sw_flags;
 134                         GETSWDEVNAME(swinfo.sw_dev, swap_ary[i].ksw_devname,
 135                              flags);
 136                 }
 137                 tot.ksw_total += ttl;
 138                 tot.ksw_used += swinfo.sw_used;
 139                 sp = TAILQ_NEXT(&swinfo, sw_list);
 140         }
 141
 142         if (i >= swap_max)
 143                 i = swap_max - 1;
 144         if (i >= 0)
 145                 swap_ary[i] = tot;
 146
 147         return(i);
 148 }
 149
 150 #define GETSYSCTL(kd, name, var)                                        \
 151             getsysctl(kd, name, &(var), sizeof(var))
 152
 153 /* The maximum MIB length for vm.swap_info and an additional device number */
 154 #define SWI_MAXMIB      3
 155
 156 int
 157 kvm_getswapinfo_sysctl(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max,
 158     int flags)
 159 {
 160         int ti, ttl;
 161         size_t mibi, len;
 162         int soid[SWI_MAXMIB];
 163         struct xswdev xsd;
 164         struct kvm_swap tot;
 165
 166         if (!GETSYSCTL(kd, "vm.dmmax", dmmax))
 167                 return -1;
 168
 169         mibi = SWI_MAXMIB - 1;
 170         if (sysctlnametomib("vm.swap_info", soid, &mibi) == -1) {
 171                 _kvm_err(kd, kd->program, "sysctlnametomib failed: %s",
 172                     strerror(errno));
 173                 return -1;
 174         }
 175         bzero(&tot, sizeof(tot));
 176         for (unswdev = 0;; unswdev++) {
 177                 soid[mibi] = unswdev;
 178                 len = sizeof(xsd);
 179                 if (sysctl(soid, mibi + 1, &xsd, &len, NULL, 0) == -1) {
 180                         if (errno == ENOENT)
 181                                 break;
 182                         _kvm_err(kd, kd->program, "cannot read sysctl: %s.",
 183                             strerror(errno));
 184                         return -1;
 185                 }
 186                 if (len != sizeof(xsd)) {
 187                         _kvm_err(kd, kd->program, "struct xswdev has unexpected "
 188                             "size;  kernel and libkvm out of sync?");
 189                         return -1;
 190                 }
 191                 if (xsd.xsw_version != XSWDEV_VERSION) {
 192                         _kvm_err(kd, kd->program, "struct xswdev version "
 193                             "mismatch; kernel and libkvm out of sync?");
 194                         return -1;
 195                 }
 196
 197                 ttl = xsd.xsw_nblks - dmmax;
 198                 if (unswdev < swap_max - 1) {
 199                         bzero(&swap_ary[unswdev], sizeof(swap_ary[unswdev]));
 200                         swap_ary[unswdev].ksw_total = ttl;
 201                         swap_ary[unswdev].ksw_used = xsd.xsw_used;
 202                         swap_ary[unswdev].ksw_flags = xsd.xsw_flags;
 203                         GETSWDEVNAME(xsd.xsw_dev, swap_ary[unswdev].ksw_devname,
 204                              flags);
 205                 }
 206                 tot.ksw_total += ttl;
 207                 tot.ksw_used += xsd.xsw_used;
 208         }
 209
 210         ti = unswdev;
 211         if (ti >= swap_max)
 212                 ti = swap_max - 1;
 213         if (ti >= 0)
 214                 swap_ary[ti] = tot;
 215
 216         return(ti);
 217 }
 218
 219 static int
 220 nlist_init(kvm_t *kd)
 221 {
 222
 223         if (kvm_swap_nl_cached)
 224                 return (1);
 225
 226         if (kvm_nlist(kd, kvm_swap_nl) < 0)
 227                 return (0);
 228
 229         /* Required entries */
 230         if (kvm_swap_nl[NL_SWTAILQ].n_value == 0) {
 231                 _kvm_err(kd, kd->program, "unable to find swtailq");
 232                 return (0);
 233         }
 234
 235         if (kvm_swap_nl[NL_DMMAX].n_value == 0) {
 236                 _kvm_err(kd, kd->program, "unable to find dmmax");
 237                 return (0);
 238         }
 239
 240         /* Get globals, type of swap */
 241         KGET(NL_DMMAX, &dmmax);
 242
 243         kvm_swap_nl_cached = 1;
 244         return (1);
 245 }
 246
 247 static int
 248 getsysctl(kvm_t *kd, const char *name, void *ptr, size_t len)
 249 {
 250         size_t nlen = len;
 251         if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
 252                 _kvm_err(kd, kd->program, "cannot read sysctl %s:%s", name,
 253                     strerror(errno));
 254                 return (0);
 255         }
 256         if (nlen != len) {
 257                 _kvm_err(kd, kd->program, "sysctl %s has unexpected size", name);
 258                 return (0);
 259         }
 260         return (1);
 261 }