db2/btree/bt_open.c

   1 /*-
   2  * See the file LICENSE for redistribution information.
   3  *
   4  * Copyright (c) 1996, 1997, 1998
   5  *      Sleepycat Software.  All rights reserved.
   6  */
   7 /*
   8  * Copyright (c) 1990, 1993, 1994, 1995, 1996
   9  *      Keith Bostic.  All rights reserved.
  10  */
  11 /*
  12  * Copyright (c) 1990, 1993, 1994, 1995
  13  *      The Regents of the University of California.  All rights reserved.
  14  *
  15  * This code is derived from software contributed to Berkeley by
  16  * Mike Olson.
  17  *
  18  * Redistribution and use in source and binary forms, with or without
  19  * modification, are permitted provided that the following conditions
  20  * are met:
  21  * 1. Redistributions of source code must retain the above copyright
  22  *    notice, this list of conditions and the following disclaimer.
  23  * 2. Redistributions in binary form must reproduce the above copyright
  24  *    notice, this list of conditions and the following disclaimer in the
  25  *    documentation and/or other materials provided with the distribution.
  26  * 3. All advertising materials mentioning features or use of this software
  27  *    must display the following acknowledgement:
  28  *      This product includes software developed by the University of
  29  *      California, Berkeley and its contributors.
  30  * 4. Neither the name of the University nor the names of its contributors
  31  *    may be used to endorse or promote products derived from this software
  32  *    without specific prior written permission.
  33  *
  34  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  35  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  36  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  37  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  38  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  39  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  40  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  41  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  42  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  43  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  44  * SUCH DAMAGE.
  45  */
  46
  47 #include "config.h"
  48
  49 #ifndef lint
  50 static const char sccsid[] = "@(#)bt_open.c     10.27 (Sleepycat) 5/6/98";
  51 #endif /* not lint */
  52
  53 /*
  54  * Implementation of btree access method for 4.4BSD.
  55  *
  56  * The design here was originally based on that of the btree access method
  57  * used in the Postgres database system at UC Berkeley.  This implementation
  58  * is wholly independent of the Postgres code.
  59  */
  60
  61 #ifndef NO_SYSTEM_INCLUDES
  62 #include <sys/types.h>
  63
  64 #include <errno.h>
  65 #include <limits.h>
  66 #include <string.h>
  67 #endif
  68
  69 #include "db_int.h"
  70 #include "db_page.h"
  71 #include "btree.h"
  72
  73 static int __bam_keyalloc __P((BTREE *));
  74 static int __bam_setmeta __P((DB *, BTREE *));
  75
  76 /*
  77  * __bam_open --
  78  *      Open a btree.
  79  *
  80  * PUBLIC: int __bam_open __P((DB *, DBTYPE, DB_INFO *));
  81  */
  82 int
  83 __bam_open(dbp, type, dbinfo)
  84         DB *dbp;
  85         DBTYPE type;
  86         DB_INFO *dbinfo;
  87 {
  88         BTREE *t;
  89         int ret;
  90
  91         /* Allocate the btree internal structure. */
  92         if ((t = (BTREE *)__db_calloc(1, sizeof(BTREE))) == NULL)
  93                 return (ENOMEM);
  94
  95         t->bt_sp = t->bt_csp = t->bt_stack;
  96         t->bt_esp = t->bt_stack + sizeof(t->bt_stack) / sizeof(t->bt_stack[0]);
  97
  98         if ((type == DB_RECNO || F_ISSET(dbp, DB_BT_RECNUM)) &&
  99             (ret = __bam_keyalloc(t)) != 0)
 100                 goto err;
 101
 102         /*
 103          * Intention is to make sure all of the user's selections are okay
 104          * here and then use them without checking.
 105          */
 106         if (dbinfo != NULL) {
 107                 /* Minimum number of keys per page. */
 108                 if (dbinfo->bt_minkey == 0)
 109                         t->bt_minkey = DEFMINKEYPAGE;
 110                 else {
 111                         if (dbinfo->bt_minkey < 2)
 112                                 goto einval;
 113                         t->bt_minkey = dbinfo->bt_minkey;
 114                 }
 115
 116                 /* Maximum number of keys per page. */
 117                 if (dbinfo->bt_maxkey == 0)
 118                         t->bt_maxkey = 0;
 119                 else {
 120                         if (dbinfo->bt_maxkey < 1)
 121                                 goto einval;
 122                         t->bt_maxkey = dbinfo->bt_maxkey;
 123                 }
 124
 125                 /*
 126                  * If no comparison, use default comparison.  If no comparison
 127                  * and no prefix, use default prefix.  (We can't default the
 128                  * prefix if the user supplies a comparison routine; shortening
 129                  * the keys may break their comparison algorithm.)
 130                  */
 131                 t->bt_compare = dbinfo->bt_compare == NULL ?
 132                     __bam_defcmp : dbinfo->bt_compare;
 133                 t->bt_prefix = dbinfo->bt_prefix == NULL ?
 134                     (dbinfo->bt_compare == NULL ?
 135                     __bam_defpfx : NULL) : dbinfo->bt_prefix;
 136         } else {
 137                 t->bt_minkey = DEFMINKEYPAGE;
 138                 t->bt_compare = __bam_defcmp;
 139                 t->bt_prefix = __bam_defpfx;
 140         }
 141
 142         /* Initialize the remaining fields of the DB. */
 143         dbp->type = type;
 144         dbp->internal = t;
 145         dbp->cursor = __bam_cursor;
 146         dbp->del = __bam_delete;
 147         dbp->get = __bam_get;
 148         dbp->put = __bam_put;
 149         dbp->stat = __bam_stat;
 150         dbp->sync = __bam_sync;
 151
 152         /*
 153          * The btree data structure requires that at least two key/data pairs
 154          * can fit on a page, but other than that there's no fixed requirement.
 155          * Translate the minimum number of items into the bytes a key/data pair
 156          * can use before being placed on an overflow page.  We calculate for
 157          * the worst possible alignment by assuming every item requires the
 158          * maximum alignment for padding.
 159          *
 160          * Recno uses the btree bt_ovflsize value -- it's close enough.
 161          */
 162         t->bt_ovflsize = (dbp->pgsize - P_OVERHEAD) / (t->bt_minkey * P_INDX)
 163             - (BKEYDATA_PSIZE(0) + ALIGN(1, 4));
 164
 165         /* Create a root page if new tree. */
 166         if ((ret = __bam_setmeta(dbp, t)) != 0)
 167                 goto err;
 168
 169         return (0);
 170
 171 einval: ret = EINVAL;
 172
 173 err:    if (t != NULL) {
 174                 /* If we allocated room for key/data return, discard it. */
 175                 if (t->bt_rkey.data != NULL)
 176                         __db_free(t->bt_rkey.data);
 177
 178                 FREE(t, sizeof(BTREE));
 179         }
 180         return (ret);
 181 }
 182
 183 /*
 184  * __bam_bdup --
 185  *      Create a BTREE handle for a threaded DB handle.
 186  *
 187  * PUBLIC: int __bam_bdup __P((DB *, DB *));
 188  */
 189 int
 190 __bam_bdup(orig, new)
 191         DB *orig, *new;
 192 {
 193         BTREE *t, *ot;
 194         int ret;
 195
 196         ot = orig->internal;
 197
 198         if ((t = (BTREE *)__db_calloc(1, sizeof(*t))) == NULL)
 199                 return (ENOMEM);
 200
 201         /*
 202          * !!!
 203          * Ignore the cursor queue, only the first DB has attached cursors.
 204          */
 205
 206         t->bt_sp = t->bt_csp = t->bt_stack;
 207         t->bt_esp = t->bt_stack + sizeof(t->bt_stack) / sizeof(t->bt_stack[0]);
 208
 209         if ((orig->type == DB_RECNO || F_ISSET(orig, DB_BT_RECNUM)) &&
 210             (ret = __bam_keyalloc(t)) != 0) {
 211                 FREE(t, sizeof(*t));
 212                 return (ret);
 213         }
 214
 215         t->bt_maxkey = ot->bt_maxkey;
 216         t->bt_minkey = ot->bt_minkey;
 217         t->bt_compare = ot->bt_compare;
 218         t->bt_prefix = ot->bt_prefix;
 219         t->bt_ovflsize = ot->bt_ovflsize;
 220
 221         /*
 222          * !!!
 223          * The entire RECNO structure is shared.  If it breaks, the application
 224          * was misusing it to start with.
 225          */
 226         t->bt_recno = ot->bt_recno;
 227
 228         new->internal = t;
 229
 230         return (0);
 231 }
 232
 233 /*
 234  * __bam_keyalloc --
 235  *      Allocate return memory for recno keys.
 236  */
 237 static int
 238 __bam_keyalloc(t)
 239         BTREE *t;
 240 {
 241         /*
 242          * Recno keys are always the same size, and we don't want to have
 243          * to check for space on each return.  Allocate it now.
 244          */
 245         if ((t->bt_rkey.data = (void *)__db_malloc(sizeof(db_recno_t))) == NULL)
 246                 return (ENOMEM);
 247         t->bt_rkey.ulen = sizeof(db_recno_t);
 248         return (0);
 249 }
 250
 251 /*
 252  * __bam_setmeta --
 253  *      Check (and optionally create) a tree.
 254  */
 255 static int
 256 __bam_setmeta(dbp, t)
 257         DB *dbp;
 258         BTREE *t;
 259 {
 260         BTMETA *meta;
 261         PAGE *root;
 262         DB_LOCK metalock, rootlock;
 263         db_pgno_t pgno;
 264         int ret;
 265
 266         /* Get, and optionally create the metadata page. */
 267         pgno = PGNO_METADATA;
 268         if ((ret =
 269             __bam_lget(dbp, 0, PGNO_METADATA, DB_LOCK_WRITE, &metalock)) != 0)
 270                 return (ret);
 271         if ((ret =
 272             __bam_pget(dbp, (PAGE **)&meta, &pgno, DB_MPOOL_CREATE)) != 0) {
 273                 (void)__BT_LPUT(dbp, metalock);
 274                 return (ret);
 275         }
 276
 277         /*
 278          * If the magic number is correct, we're not creating the tree.
 279          * Correct any fields that may not be right.  Note, all of the
 280          * local flags were set by db_open(3).
 281          */
 282         if (meta->magic != 0) {
 283                 t->bt_maxkey = meta->maxkey;
 284                 t->bt_minkey = meta->minkey;
 285
 286                 (void)memp_fput(dbp->mpf, (PAGE *)meta, 0);
 287                 (void)__BT_LPUT(dbp, metalock);
 288                 return (0);
 289         }
 290
 291         /* Initialize the tree structure metadata information. */
 292         memset(meta, 0, sizeof(BTMETA));
 293         ZERO_LSN(meta->lsn);
 294         meta->pgno = PGNO_METADATA;
 295         meta->magic = DB_BTREEMAGIC;
 296         meta->version = DB_BTREEVERSION;
 297         meta->pagesize = dbp->pgsize;
 298         meta->maxkey = t->bt_maxkey;
 299         meta->minkey = t->bt_minkey;
 300         meta->free = PGNO_INVALID;
 301         if (dbp->type == DB_RECNO)
 302                 F_SET(meta, BTM_RECNO);
 303         if (F_ISSET(dbp, DB_AM_DUP))
 304                 F_SET(meta, BTM_DUP);
 305         if (F_ISSET(dbp, DB_RE_FIXEDLEN))
 306                 F_SET(meta, BTM_FIXEDLEN);
 307         if (F_ISSET(dbp, DB_BT_RECNUM))
 308                 F_SET(meta, BTM_RECNUM);
 309         if (F_ISSET(dbp, DB_RE_RENUMBER))
 310                 F_SET(meta, BTM_RENUMBER);
 311         memcpy(meta->uid, dbp->lock.fileid, DB_FILE_ID_LEN);
 312
 313         /* Create and initialize a root page. */
 314         pgno = PGNO_ROOT;
 315         if ((ret =
 316             __bam_lget(dbp, 0, PGNO_ROOT, DB_LOCK_WRITE, &rootlock)) != 0)
 317                 return (ret);
 318         if ((ret = __bam_pget(dbp, &root, &pgno, DB_MPOOL_CREATE)) != 0) {
 319                 (void)__BT_LPUT(dbp, rootlock);
 320                 return (ret);
 321         }
 322         P_INIT(root, dbp->pgsize, PGNO_ROOT, PGNO_INVALID,
 323             PGNO_INVALID, 1, dbp->type == DB_RECNO ? P_LRECNO : P_LBTREE);
 324         ZERO_LSN(root->lsn);
 325
 326         /* Release the metadata and root pages. */
 327         if ((ret = memp_fput(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY)) != 0)
 328                 return (ret);
 329         if ((ret = memp_fput(dbp->mpf, root, DB_MPOOL_DIRTY)) != 0)
 330                 return (ret);
 331
 332         /*
 333          * Flush the metadata and root pages to disk -- since the user can't
 334          * transaction protect open, the pages have to exist during recovery.
 335          *
 336          * XXX
 337          * It's not useful to return not-yet-flushed here -- convert it to
 338          * an error.
 339          */
 340         if ((ret = memp_fsync(dbp->mpf)) == DB_INCOMPLETE)
 341                 ret = EINVAL;
 342
 343         /* Release the locks. */
 344         (void)__BT_LPUT(dbp, metalock);
 345         (void)__BT_LPUT(dbp, rootlock);
 346
 347         return (ret);
 348 }