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/vm_param.h>
  37
  38 #include <err.h>
  39 #include <errno.h>
  40 #include <fcntl.h>
  41 #include <kvm.h>
  42 #include <nlist.h>
  43 #include <paths.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <unistd.h>
  48 #include <limits.h>
  49
  50 #include "kvm_private.h"
  51
  52 #define NL_SWAPBLIST    0
  53 #define NL_SWDEVT       1
  54 #define NL_NSWDEV       2
  55 #define NL_DMMAX        3
  56
  57 static int kvm_swap_nl_cached = 0;
  58 static int unswdev;  /* number of found swap dev's */
  59 static int dmmax;
  60
  61 static int  kvm_getswapinfo_sysctl(kvm_t *, struct kvm_swap *, int, int);
  62 static int  getsysctl(kvm_t *, char *, void *, size_t);
  63
  64 #define GETSWDEVNAME(dev, str, flags)                                   \
  65         if (dev == NODEV) {                                             \
  66                 strlcpy(str, "[NFS swap]", sizeof(str));                \
  67         } else {                                                        \
  68                 snprintf(                                               \
  69                     str, sizeof(str),"%s%s",                            \
  70                     ((flags & SWIF_DEV_PREFIX) ? _PATH_DEV : ""),       \
  71                     devname(dev, S_IFCHR)                               \
  72                 );                                                      \
  73         }
  74
  75 int
  76 kvm_getswapinfo(
  77         kvm_t *kd,
  78         struct kvm_swap *swap_ary,
  79         int swap_max,
  80         int flags
  81 ) {
  82
  83         /*
  84          * clear cache
  85          */
  86         if (kd == NULL) {
  87                 kvm_swap_nl_cached = 0;
  88                 return(0);
  89         }
  90
  91         if (ISALIVE(kd)) {
  92                 return kvm_getswapinfo_sysctl(kd, swap_ary, swap_max, flags);
  93         } else {
  94                 return -1;
  95         }
  96 }
  97
  98 #define GETSYSCTL(kd, name, var)                                        \
  99             getsysctl(kd, name, &(var), sizeof(var))
 100
 101 /* The maximum MIB length for vm.swap_info and an additional device number */
 102 #define SWI_MAXMIB      3
 103
 104 int
 105 kvm_getswapinfo_sysctl(
 106         kvm_t *kd,
 107         struct kvm_swap *swap_ary,
 108         int swap_max,
 109         int flags
 110 ) {
 111         int ti, ttl;
 112         size_t mibi, len;
 113         int soid[SWI_MAXMIB];
 114         struct xswdev xsd;
 115         struct kvm_swap tot;
 116
 117         if (!GETSYSCTL(kd, "vm.dmmax", dmmax))
 118                 return -1;
 119
 120         mibi = SWI_MAXMIB - 1;
 121         if (sysctlnametomib("vm.swap_info", soid, &mibi) == -1) {
 122                 _kvm_err(kd, kd->program, "sysctlnametomib failed: %s",
 123                     strerror(errno));
 124                 return -1;
 125         }
 126         bzero(&tot, sizeof(tot));
 127         for (unswdev = 0;; unswdev++) {
 128                 soid[mibi] = unswdev;
 129                 len = sizeof(xsd);
 130                 if (sysctl(soid, mibi + 1, &xsd, &len, NULL, 0) == -1) {
 131                         if (errno == ENOENT)
 132                                 break;
 133                         _kvm_err(kd, kd->program, "cannot read sysctl: %s.",
 134                             strerror(errno));
 135                         return -1;
 136                 }
 137                 if (len != sizeof(xsd)) {
 138                         _kvm_err(kd, kd->program, "struct xswdev has unexpected "
 139                             "size;  kernel and libkvm out of sync?");
 140                         return -1;
 141                 }
 142                 if (xsd.xsw_version != XSWDEV_VERSION) {
 143                         _kvm_err(kd, kd->program, "struct xswdev version "
 144                             "mismatch; kernel and libkvm out of sync?");
 145                         return -1;
 146                 }
 147
 148                 ttl = xsd.xsw_nblks - dmmax;
 149                 if (unswdev < swap_max - 1) {
 150                         bzero(&swap_ary[unswdev], sizeof(swap_ary[unswdev]));
 151                         swap_ary[unswdev].ksw_total = ttl;
 152                         swap_ary[unswdev].ksw_used = xsd.xsw_used;
 153                         swap_ary[unswdev].ksw_flags = xsd.xsw_flags;
 154                         GETSWDEVNAME(xsd.xsw_dev, swap_ary[unswdev].ksw_devname,
 155                              flags);
 156                 }
 157                 tot.ksw_total += ttl;
 158                 tot.ksw_used += xsd.xsw_used;
 159         }
 160
 161         ti = unswdev;
 162         if (ti >= swap_max)
 163                 ti = swap_max - 1;
 164         if (ti >= 0)
 165                 swap_ary[ti] = tot;
 166
 167         return(ti);
 168 }
 169
 170 static int
 171 getsysctl (
 172         kvm_t *kd,
 173         char *name,
 174         void *ptr,
 175         size_t len
 176 ) {
 177         size_t nlen = len;
 178         if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
 179                 _kvm_err(kd, kd->program, "cannot read sysctl %s:%s", name,
 180                     strerror(errno));
 181                 return (0);
 182         }
 183         if (nlen != len) {
 184                 _kvm_err(kd, kd->program, "sysctl %s has unexpected size", name);
 185                 return (0);
 186         }
 187         return (1);
 188 }