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 10.39 (Sleepycat) 11/21/98";
51 #endif /* not lint */
52
53 #ifndef NO_SYSTEM_INCLUDES
54 #include <sys/types.h>
55
56 #include <errno.h>
57 #include <limits.h>
58 #include <string.h>
59 #endif
60
61 #include "db_int.h"
62 #include "db_page.h"
63 #include "btree.h"
64
65 /*
66 * __bam_open --
67 * Open a btree.
68 *
69 * PUBLIC: int __bam_open __P((DB *, DB_INFO *));
70 */
71 int
__bam_open(dbp,dbinfo)72 __bam_open(dbp, dbinfo)
73 DB *dbp;
74 DB_INFO *dbinfo;
75 {
76 BTREE *t;
77 int ret;
78
79 /* Allocate and initialize the private btree structure. */
80 if ((ret = __os_calloc(1, sizeof(BTREE), &t)) != 0)
81 return (ret);
82 dbp->internal = t;
83
84 /*
85 * Intention is to make sure all of the user's selections are okay
86 * here and then use them without checking.
87 */
88 if (dbinfo == NULL) {
89 t->bt_minkey = DEFMINKEYPAGE;
90 t->bt_compare = __bam_defcmp;
91 t->bt_prefix = __bam_defpfx;
92 } else {
93 /* Minimum number of keys per page. */
94 if (dbinfo->bt_minkey == 0)
95 t->bt_minkey = DEFMINKEYPAGE;
96 else {
97 if (dbinfo->bt_minkey < 2)
98 goto einval;
99 t->bt_minkey = dbinfo->bt_minkey;
100 }
101
102 /* Maximum number of keys per page. */
103 if (dbinfo->bt_maxkey == 0)
104 t->bt_maxkey = 0;
105 else {
106 if (dbinfo->bt_maxkey < 1)
107 goto einval;
108 t->bt_maxkey = dbinfo->bt_maxkey;
109 }
110
111 /*
112 * If no comparison, use default comparison. If no comparison
113 * and no prefix, use default prefix. (We can't default the
114 * prefix if the user supplies a comparison routine; shortening
115 * the keys may break their comparison algorithm. We don't
116 * permit the user to specify a prefix routine if they didn't
117 * also specify a comparison routine, they can't know enough
118 * about our comparison routine to get it right.)
119 */
120 if ((t->bt_compare = dbinfo->bt_compare) == NULL) {
121 if (dbinfo->bt_prefix != NULL)
122 goto einval;
123 t->bt_compare = __bam_defcmp;
124 t->bt_prefix = __bam_defpfx;
125 } else
126 t->bt_prefix = dbinfo->bt_prefix;
127 }
128
129 /* Initialize the remaining fields/methods of the DB. */
130 dbp->am_close = __bam_close;
131 dbp->del = __bam_delete;
132 dbp->stat = __bam_stat;
133
134 /* Start up the tree. */
135 if ((ret = __bam_read_root(dbp)) != 0)
136 goto err;
137
138 /* Set the overflow page size. */
139 __bam_setovflsize(dbp);
140
141 return (0);
142
143 einval: ret = EINVAL;
144
145 err: __os_free(t, sizeof(BTREE));
146 return (ret);
147 }
148
149 /*
150 * __bam_close --
151 * Close a btree.
152 *
153 * PUBLIC: int __bam_close __P((DB *));
154 */
155 int
__bam_close(dbp)156 __bam_close(dbp)
157 DB *dbp;
158 {
159 __os_free(dbp->internal, sizeof(BTREE));
160 dbp->internal = NULL;
161
162 return (0);
163 }
164
165 /*
166 * __bam_setovflsize --
167 *
168 * PUBLIC: void __bam_setovflsize __P((DB *));
169 */
170 void
__bam_setovflsize(dbp)171 __bam_setovflsize(dbp)
172 DB *dbp;
173 {
174 BTREE *t;
175
176 t = dbp->internal;
177
178 /*
179 * !!!
180 * Correction for recno, which doesn't know anything about minimum
181 * keys per page.
182 */
183 if (t->bt_minkey == 0)
184 t->bt_minkey = DEFMINKEYPAGE;
185
186 /*
187 * The btree data structure requires that at least two key/data pairs
188 * can fit on a page, but other than that there's no fixed requirement.
189 * Translate the minimum number of items into the bytes a key/data pair
190 * can use before being placed on an overflow page. We calculate for
191 * the worst possible alignment by assuming every item requires the
192 * maximum alignment for padding.
193 *
194 * Recno uses the btree bt_ovflsize value -- it's close enough.
195 */
196 t->bt_ovflsize = (dbp->pgsize - P_OVERHEAD) / (t->bt_minkey * P_INDX)
197 - (BKEYDATA_PSIZE(0) + ALIGN(1, 4));
198 }
199
200 /*
201 * __bam_read_root --
202 * Check (and optionally create) a tree.
203 *
204 * PUBLIC: int __bam_read_root __P((DB *));
205 */
206 int
__bam_read_root(dbp)207 __bam_read_root(dbp)
208 DB *dbp;
209 {
210 BTMETA *meta;
211 BTREE *t;
212 DBC *dbc;
213 DB_LOCK metalock, rootlock;
214 PAGE *root;
215 db_pgno_t pgno;
216 int ret, t_ret;
217
218 ret = 0;
219 t = dbp->internal;
220
221 /* Get a cursor. */
222 if ((ret = dbp->cursor(dbp, NULL, &dbc, 0)) != 0)
223 return (ret);
224
225 /* Get, and optionally create the metadata page. */
226 pgno = PGNO_METADATA;
227 if ((ret =
228 __bam_lget(dbc, 0, PGNO_METADATA, DB_LOCK_WRITE, &metalock)) != 0)
229 goto err;
230 if ((ret =
231 memp_fget(dbp->mpf, &pgno, DB_MPOOL_CREATE, (PAGE **)&meta)) != 0) {
232 (void)__BT_LPUT(dbc, metalock);
233 goto err;
234 }
235
236 /*
237 * If the magic number is correct, we're not creating the tree.
238 * Correct any fields that may not be right. Note, all of the
239 * local flags were set by db_open(3).
240 */
241 if (meta->magic != 0) {
242 t->bt_maxkey = meta->maxkey;
243 t->bt_minkey = meta->minkey;
244
245 (void)memp_fput(dbp->mpf, (PAGE *)meta, 0);
246 (void)__BT_LPUT(dbc, metalock);
247 goto done;
248 }
249
250 /* Initialize the tree structure metadata information. */
251 memset(meta, 0, sizeof(BTMETA));
252 ZERO_LSN(meta->lsn);
253 meta->pgno = PGNO_METADATA;
254 meta->magic = DB_BTREEMAGIC;
255 meta->version = DB_BTREEVERSION;
256 meta->pagesize = dbp->pgsize;
257 meta->maxkey = t->bt_maxkey;
258 meta->minkey = t->bt_minkey;
259 meta->free = PGNO_INVALID;
260 if (dbp->type == DB_RECNO)
261 F_SET(meta, BTM_RECNO);
262 if (F_ISSET(dbp, DB_AM_DUP))
263 F_SET(meta, BTM_DUP);
264 if (F_ISSET(dbp, DB_RE_FIXEDLEN))
265 F_SET(meta, BTM_FIXEDLEN);
266 if (F_ISSET(dbp, DB_BT_RECNUM))
267 F_SET(meta, BTM_RECNUM);
268 if (F_ISSET(dbp, DB_RE_RENUMBER))
269 F_SET(meta, BTM_RENUMBER);
270 memcpy(meta->uid, dbp->fileid, DB_FILE_ID_LEN);
271
272 /* Create and initialize a root page. */
273 pgno = PGNO_ROOT;
274 if ((ret =
275 __bam_lget(dbc, 0, PGNO_ROOT, DB_LOCK_WRITE, &rootlock)) != 0)
276 goto err;
277 if ((ret = memp_fget(dbp->mpf, &pgno, DB_MPOOL_CREATE, &root)) != 0) {
278 (void)__BT_LPUT(dbc, rootlock);
279 goto err;
280 }
281 P_INIT(root, dbp->pgsize, PGNO_ROOT, PGNO_INVALID,
282 PGNO_INVALID, 1, dbp->type == DB_RECNO ? P_LRECNO : P_LBTREE);
283 ZERO_LSN(root->lsn);
284
285 /* Release the metadata and root pages. */
286 if ((ret = memp_fput(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY)) != 0)
287 goto err;
288 if ((ret = memp_fput(dbp->mpf, root, DB_MPOOL_DIRTY)) != 0)
289 goto err;
290
291 /*
292 * Flush the metadata and root pages to disk -- since the user can't
293 * transaction protect open, the pages have to exist during recovery.
294 *
295 * XXX
296 * It's not useful to return not-yet-flushed here -- convert it to
297 * an error.
298 */
299 if ((ret = memp_fsync(dbp->mpf)) == DB_INCOMPLETE)
300 ret = EINVAL;
301
302 /* Release the locks. */
303 (void)__BT_LPUT(dbc, metalock);
304 (void)__BT_LPUT(dbc, rootlock);
305
306 err:
307 done: if ((t_ret = dbc->c_close(dbc)) != 0 && ret == 0)
308 ret = t_ret;
309 return (ret);
310 }
311