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