xref: /freebsd/lib/libc/db/btree/bt_get.c (revision f5463265955b829775bbb32e1fd0bc11dafc36ce)
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 #include <sys/types.h>
36 
37 #include <errno.h>
38 #include <stddef.h>
39 #include <stdio.h>
40 
41 #include <db.h>
42 #include "btree.h"
43 
44 /*
45  * __BT_GET -- Get a record from the btree.
46  *
47  * Parameters:
48  *	dbp:	pointer to access method
49  *	key:	key to find
50  *	data:	data to return
51  *	flag:	currently unused
52  *
53  * Returns:
54  *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
55  */
56 int
57 __bt_get(const DB *dbp, const DBT *key, DBT *data, u_int flags)
58 {
59 	BTREE *t;
60 	EPG *e;
61 	int exact, status;
62 
63 	t = dbp->internal;
64 
65 	/* Toss any page pinned across calls. */
66 	if (t->bt_pinned != NULL) {
67 		mpool_put(t->bt_mp, t->bt_pinned, 0);
68 		t->bt_pinned = NULL;
69 	}
70 
71 	/* Get currently doesn't take any flags. */
72 	if (flags) {
73 		errno = EINVAL;
74 		return (RET_ERROR);
75 	}
76 
77 	if ((e = __bt_search(t, key, &exact)) == NULL)
78 		return (RET_ERROR);
79 	if (!exact) {
80 		mpool_put(t->bt_mp, e->page, 0);
81 		return (RET_SPECIAL);
82 	}
83 
84 	status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
85 
86 	/*
87 	 * If the user is doing concurrent access, we copied the
88 	 * key/data, toss the page.
89 	 */
90 	if (F_ISSET(t, B_DB_LOCK))
91 		mpool_put(t->bt_mp, e->page, 0);
92 	else
93 		t->bt_pinned = e->page;
94 	return (status);
95 }
96