xref: /freebsd/lib/libc/db/btree/bt_get.c (revision e3e9c205ff54aac287309e03a808d9e9ec5c49eb)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1990, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Mike Olson.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)bt_get.c	8.6 (Berkeley) 7/20/94";
37 #endif /* LIBC_SCCS and not lint */
38 #include <sys/types.h>
39 
40 #include <errno.h>
41 #include <stddef.h>
42 #include <stdio.h>
43 
44 #include <db.h>
45 #include "btree.h"
46 
47 /*
48  * __BT_GET -- Get a record from the btree.
49  *
50  * Parameters:
51  *	dbp:	pointer to access method
52  *	key:	key to find
53  *	data:	data to return
54  *	flag:	currently unused
55  *
56  * Returns:
57  *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
58  */
59 int
60 __bt_get(const DB *dbp, const DBT *key, DBT *data, u_int flags)
61 {
62 	BTREE *t;
63 	EPG *e;
64 	int exact, status;
65 
66 	t = dbp->internal;
67 
68 	/* Toss any page pinned across calls. */
69 	if (t->bt_pinned != NULL) {
70 		mpool_put(t->bt_mp, t->bt_pinned, 0);
71 		t->bt_pinned = NULL;
72 	}
73 
74 	/* Get currently doesn't take any flags. */
75 	if (flags) {
76 		errno = EINVAL;
77 		return (RET_ERROR);
78 	}
79 
80 	if ((e = __bt_search(t, key, &exact)) == NULL)
81 		return (RET_ERROR);
82 	if (!exact) {
83 		mpool_put(t->bt_mp, e->page, 0);
84 		return (RET_SPECIAL);
85 	}
86 
87 	status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
88 
89 	/*
90 	 * If the user is doing concurrent access, we copied the
91 	 * key/data, toss the page.
92 	 */
93 	if (F_ISSET(t, B_DB_LOCK))
94 		mpool_put(t->bt_mp, e->page, 0);
95 	else
96 		t->bt_pinned = e->page;
97 	return (status);
98 }
99