1 /* $NetBSD: testdb.c,v 1.4 1996/10/12 00:51:46 cgd 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #ifndef lint 37 #if 0 38 static char sccsid[] = "from: @(#)testdb.c 8.1 (Berkeley) 6/6/93"; 39 #else 40 static char *rcsid = "$NetBSD: testdb.c,v 1.4 1996/10/12 00:51:46 cgd Exp $"; 41 #endif 42 #endif /* not lint */ 43 44 #include <sys/param.h> 45 #include <sys/file.h> 46 #include <errno.h> 47 #include <limits.h> 48 #include <kvm.h> 49 #include <db.h> 50 #include <stdio.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 register DB *db; 62 register int cc, kd, ret, dbversionlen; 63 DBT rec; 64 struct nlist nitem; 65 char dbversion[_POSIX2_LINE_MAX]; 66 char kversion[_POSIX2_LINE_MAX]; 67 68 ret = 0; 69 db = NULL; 70 71 if ((kd = open(_PATH_KMEM, O_RDONLY, 0)) < 0) 72 goto close; 73 74 if ((db = dbopen(_PATH_KVMDB, O_RDONLY, 0, DB_HASH, NULL)) == NULL) 75 goto close; 76 77 /* Read the version out of the database */ 78 rec.data = VRS_KEY; 79 rec.size = sizeof(VRS_KEY) - 1; 80 if ((db->get)(db, &rec, &rec, 0)) 81 goto close; 82 if (rec.data == 0 || rec.size > sizeof(dbversion)) 83 goto close; 84 bcopy(rec.data, dbversion, rec.size); 85 dbversionlen = rec.size; 86 87 /* Read version string from kernel memory */ 88 rec.data = VRS_SYM; 89 rec.size = sizeof(VRS_SYM) - 1; 90 if ((db->get)(db, &rec, &rec, 0)) 91 goto close; 92 if (rec.data == 0 || rec.size != sizeof(struct nlist)) 93 goto close; 94 bcopy(rec.data, &nitem, sizeof(nitem)); 95 /* 96 * Theoretically possible for lseek to be seeking to -1. Not 97 * that it's something to lie awake nights about, however. 98 */ 99 errno = 0; 100 if (lseek(kd, (off_t)nitem.n_value, SEEK_SET) == -1 && errno != 0) 101 goto close; 102 cc = read(kd, kversion, sizeof(kversion)); 103 if (cc < 0 || cc != sizeof(kversion)) 104 goto close; 105 106 /* If they match, we win */ 107 ret = bcmp(dbversion, kversion, dbversionlen) == 0; 108 109 close: if (kd >= 0) 110 (void)close(kd); 111 if (db) 112 (void)(db->close)(db); 113 return (ret); 114 } 115