xref: /freebsd/lib/libc/db/btree/bt_get.c (revision 74bf4e164ba5851606a27d4feff27717452583e5)
1 /*-
2  * Copyright (c) 1990, 1993, 1994
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Mike Olson.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)bt_get.c	8.6 (Berkeley) 7/20/94";
39 #endif /* LIBC_SCCS and not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include <sys/types.h>
44 
45 #include <errno.h>
46 #include <stddef.h>
47 #include <stdio.h>
48 
49 #include <db.h>
50 #include "btree.h"
51 
52 /*
53  * __BT_GET -- Get a record from the btree.
54  *
55  * Parameters:
56  *	dbp:	pointer to access method
57  *	key:	key to find
58  *	data:	data to return
59  *	flag:	currently unused
60  *
61  * Returns:
62  *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
63  */
64 int
65 __bt_get(dbp, key, data, flags)
66 	const DB *dbp;
67 	const DBT *key;
68 	DBT *data;
69 	u_int flags;
70 {
71 	BTREE *t;
72 	EPG *e;
73 	int exact, status;
74 
75 	t = dbp->internal;
76 
77 	/* Toss any page pinned across calls. */
78 	if (t->bt_pinned != NULL) {
79 		mpool_put(t->bt_mp, t->bt_pinned, 0);
80 		t->bt_pinned = NULL;
81 	}
82 
83 	/* Get currently doesn't take any flags. */
84 	if (flags) {
85 		errno = EINVAL;
86 		return (RET_ERROR);
87 	}
88 
89 	if ((e = __bt_search(t, key, &exact)) == NULL)
90 		return (RET_ERROR);
91 	if (!exact) {
92 		mpool_put(t->bt_mp, e->page, 0);
93 		return (RET_SPECIAL);
94 	}
95 
96 	status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
97 
98 	/*
99 	 * If the user is doing concurrent access, we copied the
100 	 * key/data, toss the page.
101 	 */
102 	if (F_ISSET(t, B_DB_LOCK))
103 		mpool_put(t->bt_mp, e->page, 0);
104 	else
105 		t->bt_pinned = e->page;
106 	return (status);
107 }
108