kvm_mkdb.tproj/testdb.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * "Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
   7  * Reserved.  This file contains Original Code and/or Modifications of
   8  * Original Code as defined in and that are subject to the Apple Public
   9  * Source License Version 1.0 (the 'License').  You may not use this file
  10  * except in compliance with the License.  Please obtain a copy of the
  11  * License at http://www.apple.com/publicsource and read it before using
  12  * this file.
  13  *
  14  * The Original Code and all software distributed under the License are
  15  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  16  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  17  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  19  * License for the specific language governing rights and limitations
  20  * under the License."
  21  *
  22  * @APPLE_LICENSE_HEADER_END@
  23  */
  24 /*-
  25  * Copyright (c) 1992, 1993
  26  *      The Regents of the University of California.  All rights reserved.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Redistributions in binary form must reproduce the above copyright
  34  *    notice, this list of conditions and the following disclaimer in the
  35  *    documentation and/or other materials provided with the distribution.
  36  * 3. All advertising materials mentioning features or use of this software
  37  *    must display the following acknowledgement:
  38  *      This product includes software developed by the University of
  39  *      California, Berkeley and its contributors.
  40  * 4. Neither the name of the University nor the names of its contributors
  41  *    may be used to endorse or promote products derived from this software
  42  *    without specific prior written permission.
  43  *
  44  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  45  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  46  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  47  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  48  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  49  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  50  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  51  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  52  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  53  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  54  * SUCH DAMAGE.
  55  */
  56
  57 #ifndef lint
  58 static char sccsid[] = "@(#)testdb.c    8.1 (Berkeley) 6/6/93";
  59 #endif /* not lint */
  60
  61 #include <sys/param.h>
  62 #include <sys/file.h>
  63 #include <errno.h>
  64 #include <limits.h>
  65 #include <kvm.h>
  66 #include <db.h>
  67 #include <stdio.h>
  68 #include <unistd.h>
  69 #include <string.h>
  70 #include <paths.h>
  71
  72 #include "extern.h"
  73
  74 /* Return true if the db file is valid, else false */
  75 int
  76 testdb()
  77 {
  78         register DB *db;
  79         register int cc, kd, ret, dbversionlen;
  80         register char *cp, *uf;
  81         DBT rec;
  82         struct nlist nitem;
  83         char dbname[MAXPATHLEN], dbversion[_POSIX2_LINE_MAX];
  84         char kversion[_POSIX2_LINE_MAX];
  85
  86         ret = 0;
  87         db = NULL;
  88
  89         if ((kd = open(_PATH_KMEM, O_RDONLY, 0)) < 0)
  90                 goto close;
  91
  92         uf = _PATH_UNIX;
  93         if ((cp = rindex(uf, '/')) != 0)
  94                 uf = cp + 1;
  95         (void) snprintf(dbname, sizeof(dbname), "%skvm_%s.db", _PATH_VARDB, uf);
  96         if ((db = dbopen(dbname, O_RDONLY, 0, DB_HASH, NULL)) == NULL)
  97                 goto close;
  98
  99         /* Read the version out of the database */
 100         rec.data = VRS_KEY;
 101         rec.size = sizeof(VRS_KEY) - 1;
 102         if ((db->get)(db, &rec, &rec, 0))
 103                 goto close;
 104         if (rec.data == 0 || rec.size > sizeof(dbversion))
 105                 goto close;
 106         bcopy(rec.data, dbversion, rec.size);
 107         dbversionlen = rec.size;
 108
 109         /* Read version string from kernel memory */
 110         rec.data = VRS_SYM;
 111         rec.size = sizeof(VRS_SYM) - 1;
 112         if ((db->get)(db, &rec, &rec, 0))
 113                 goto close;
 114         if (rec.data == 0 || rec.size != sizeof(struct nlist))
 115                 goto close;
 116         bcopy(rec.data, &nitem, sizeof(nitem));
 117         /*
 118          * Theoretically possible for lseek to be seeking to -1.  Not
 119          * that it's something to lie awake nights about, however.
 120          */
 121         errno = 0;
 122         if (lseek(kd, (off_t)nitem.n_value, SEEK_SET) == -1 && errno != 0)
 123                 goto close;
 124         cc = read(kd, kversion, sizeof(kversion));
 125         if (cc < 0 || cc != sizeof(kversion))
 126                 goto close;
 127
 128         /* If they match, we win */
 129         ret = bcmp(dbversion, kversion, dbversionlen) == 0;
 130
 131 close:  if (kd >= 0)
 132                 (void)close(kd);
 133         if (db)
 134                 (void)(db->close)(db);
 135         return (ret);
 136 }