dbm/src/db.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  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  * 3. ***REMOVED*** - see
  14  *    ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change
  15  * 4. 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 #if defined(LIBC_SCCS) && !defined(lint)
  33 static char sccsid[] = "@(#)db.c        8.4 (Berkeley) 2/21/94";
  34 #endif /* LIBC_SCCS and not lint */
  35
  36 #include "watcomfx.h"
  37
  38 #ifndef __DBINTERFACE_PRIVATE
  39 #define __DBINTERFACE_PRIVATE
  40 #endif
  41 #ifdef macintosh
  42 #include <unix.h>
  43 #else
  44 #include <sys/types.h>
  45 #endif
  46
  47 #include <errno.h>
  48 #include <fcntl.h>
  49 #include <stddef.h>
  50 #include <stdio.h>
  51
  52 #include "mcom_db.h"
  53
  54 /* a global flag that locks closed all databases */
  55 int all_databases_locked_closed = 0;
  56
  57 /* set or unset a global lock flag to disable the
  58  * opening of any DBM file
  59  */
  60 void
  61 dbSetOrClearDBLock(DBLockFlagEnum type)
  62 {
  63         if(type == LockOutDatabase)
  64                 all_databases_locked_closed = 1;
  65         else
  66                 all_databases_locked_closed = 0;
  67 }
  68
  69 #if defined(__WATCOMC__) || defined(__WATCOM_CPLUSPLUS__)
  70 DB *
  71 #else
  72 PR_IMPLEMENT(DB *)
  73 #endif
  74 dbopen(const char *fname, int flags,int mode, DBTYPE type, const void *openinfo)
  75 {
  76
  77         /* lock out all file databases.  Let in-memory databases through
  78          */
  79         if(all_databases_locked_closed && fname)
  80           {
  81                 errno = EINVAL;
  82                 return(NULL);
  83           }
  84
  85 #define DB_FLAGS        (DB_LOCK | DB_SHMEM | DB_TXN)
  86
  87
  88 #if 0  /* most systems don't have EXLOCK and SHLOCK */
  89 #define USE_OPEN_FLAGS                                                  \
  90         (O_CREAT | O_EXCL | O_EXLOCK | O_NONBLOCK | O_RDONLY |          \
  91          O_RDWR | O_SHLOCK | O_TRUNC)
  92 #else
  93 #define USE_OPEN_FLAGS                                                  \
  94         (O_CREAT | O_EXCL  | O_RDONLY |         \
  95          O_RDWR | O_TRUNC)
  96 #endif
  97
  98         if ((flags & ~(USE_OPEN_FLAGS | DB_FLAGS)) == 0)
  99                 switch (type) {
 100 /* we don't need btree and recno right now */
 101 #if 0
 102                 case DB_BTREE:
 103                         return (__bt_open(fname, flags & USE_OPEN_FLAGS,
 104                             mode, openinfo, flags & DB_FLAGS));
 105                 case DB_RECNO:
 106                         return (__rec_open(fname, flags & USE_OPEN_FLAGS,
 107                             mode, openinfo, flags & DB_FLAGS));
 108 #endif
 109
 110                 case DB_HASH:
 111                         return (__hash_open(fname, flags & USE_OPEN_FLAGS,
 112                             mode, (const HASHINFO *)openinfo, flags & DB_FLAGS));
 113                 default:
 114                         break;
 115                 }
 116         errno = EINVAL;
 117         return (NULL);
 118 }
 119
 120 static int
 121 __dberr()
 122 {
 123         return (RET_ERROR);
 124 }
 125
 126 /*
 127  * __DBPANIC -- Stop.
 128  *
 129  * Parameters:
 130  *      dbp:    pointer to the DB structure.
 131  */
 132 void
 133 __dbpanic(DB *dbp)
 134 {
 135         /* The only thing that can succeed is a close. */
 136         dbp->del = (int (*)(const struct __db *, const DBT *, uint))__dberr;
 137         dbp->fd = (int (*)(const struct __db *))__dberr;
 138         dbp->get = (int (*)(const struct __db *, const DBT *, DBT *, uint))__dberr;
 139         dbp->put = (int (*)(const struct __db *, DBT *, const DBT *, uint))__dberr;
 140         dbp->seq = (int (*)(const struct __db *, DBT *, DBT *, uint))__dberr;
 141         dbp->sync = (int (*)(const struct __db *, uint))__dberr;
 142 }