1 /* $OpenBSD: testdb.c,v 1.3 1998/08/19 06:47:55 millert 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 = "$OpenBSD: testdb.c,v 1.3 1998/08/19 06:47:55 millert 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(dbname) 60 char *dbname; 61 { 62 register DB *db; 63 register int cc, kd, ret, dbversionlen; 64 DBT rec; 65 struct nlist nitem; 66 char dbversion[_POSIX2_LINE_MAX]; 67 char kversion[_POSIX2_LINE_MAX]; 68 69 ret = 0; 70 db = NULL; 71 72 if ((kd = open(_PATH_KMEM, O_RDONLY, 0)) < 0) 73 goto close; 74 75 if ((db = dbopen(dbname, O_RDONLY, 0, DB_HASH, NULL)) == NULL) 76 goto close; 77 78 /* Read the version out of the database */ 79 rec.data = VRS_KEY; 80 rec.size = sizeof(VRS_KEY) - 1; 81 if ((db->get)(db, &rec, &rec, 0)) 82 goto close; 83 if (rec.data == 0 || rec.size == 0 || rec.size > sizeof(dbversion)) 84 goto close; 85 (void)memcpy(dbversion, rec.data, rec.size); 86 dbversionlen = rec.size; 87 88 /* Read version string from kernel memory */ 89 rec.data = VRS_SYM; 90 rec.size = sizeof(VRS_SYM) - 1; 91 if ((db->get)(db, &rec, &rec, 0)) 92 goto close; 93 if (rec.data == 0 || rec.size != sizeof(struct nlist)) 94 goto close; 95 (void)memcpy(&nitem, rec.data, sizeof(nitem)); 96 /* 97 * Theoretically possible for lseek to be seeking to -1. Not 98 * that it's something to lie awake nights about, however. 99 */ 100 errno = 0; 101 if (lseek(kd, (off_t)nitem.n_value, SEEK_SET) == -1 && errno != 0) 102 goto close; 103 cc = read(kd, kversion, sizeof(kversion)); 104 if (cc < 0 || cc != sizeof(kversion)) 105 goto close; 106 107 /* If they match, we win */ 108 ret = memcmp(kversion, dbversion, dbversionlen) == 0; 109 110 close: if (kd >= 0) 111 (void)close(kd); 112 if (db) 113 (void)(db->close)(db); 114 return (ret); 115 } 116