usr.sbin/kvm_mkdb/testdb.c

   1 /*      $NetBSD: testdb.c,v 1.9 2003/05/02 16:28:34 ragge Exp $ */
   2
   3 /*-
   4  * Copyright (c) 1992, 1993
   5  *      The Regents of the University of California.  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  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #ifndef lint
  34 #if 0
  35 static char sccsid[] = "from: @(#)testdb.c      8.1 (Berkeley) 6/6/93";
  36 #else
  37 __RCSID("$NetBSD: testdb.c,v 1.9 2003/05/02 16:28:34 ragge Exp $");
  38 #endif
  39 #endif /* not lint */
  40
  41 #include <sys/param.h>
  42 #include <sys/file.h>
  43 #include <sys/sysctl.h>
  44 #include <err.h>
  45 #include <errno.h>
  46 #include <limits.h>
  47 #include <kvm.h>
  48 #include <db.h>
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <unistd.h>
  52 #include <string.h>
  53 #include <paths.h>
  54
  55 #include "extern.h"
  56
  57 /* Return true if the db file is valid, else false */
  58 int
  59 testdb()
  60 {
  61         DB *db;
  62         int ret, dbversionlen;
  63         DBT rec;
  64         char dbversion[_POSIX2_LINE_MAX];
  65         char *kversion;
  66         int mib[2];
  67         size_t size;
  68
  69         ret = 0;
  70         db = NULL;
  71
  72         if ((db = dbopen(_PATH_KVMDB, O_RDONLY, 0, DB_HASH, NULL)) == NULL)
  73                 goto close;
  74
  75         /* Read the version out of the database */
  76         rec.data = VRS_KEY;
  77         rec.size = sizeof(VRS_KEY) - 1;
  78         if ((db->get)(db, &rec, &rec, 0))
  79                 goto close;
  80         if (rec.data == 0 || rec.size == 0 || rec.size > sizeof(dbversion))
  81                 goto close;
  82         memmove(dbversion, rec.data, rec.size);
  83         dbversionlen = rec.size;
  84
  85         /* Read version string from kernel memory */
  86         mib[0] = CTL_KERN;
  87         mib[1] = KERN_VERSION;
  88         if (sysctl(mib, 2, NULL, &size, NULL, 0) == -1)
  89                 errx(1, "can't get size of kernel version string");
  90
  91         if ((kversion = malloc(size)) == NULL)
  92                 err(1, "couldn't allocate space for buffer data");
  93
  94         if (sysctl(mib, 2, kversion, &size, NULL, 0) == -1)
  95                 errx(1, "can't get kernel version string");
  96
  97         /* If they match, we win */
  98         ret = memcmp(dbversion, kversion, dbversionlen) == 0;
  99
 100 close:  if (db)
 101                 (void)(db->close)(db);
 102         return (ret);
 103 }