1 /* $NetBSD: hash.c,v 1.1 2023/07/30 09:20:14 riastradh Exp $ */
2
3 /*
4 * Copyright 1996 John D. Polstra.
5 * Copyright 1996 Matt Thomas <matt@3am-software.com>
6 * Copyright 2002 Charles M. Hannum <root@ihack.net>
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by John Polstra.
20 * 4. The name of the author may not be used to endorse or promote products
21 * derived from this software without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35 /*
36 * Dynamic linker for ELF.
37 *
38 * John Polstra <jdp@polstra.com>.
39 */
40
41 #include <sys/cdefs.h>
42 #ifndef lint
43 __RCSID("$NetBSD: hash.c,v 1.1 2023/07/30 09:20:14 riastradh Exp $");
44 #endif /* not lint */
45
46 #include <stdint.h>
47
48 #include "hash.h"
49
50 /*
51 * SysV hash function for symbol table lookup. It is a slightly optimized
52 * version of the hash specified by the System V ABI.
53 */
54 Elf32_Word
_rtld_sysv_hash(const char * name)55 _rtld_sysv_hash(const char *name)
56 {
57 const unsigned char *p = (const unsigned char *) name;
58 Elf32_Word h = 0;
59
60 while (__predict_true(*p != '\0')) {
61 h = (h << 4) + *p++;
62 h ^= (h >> 24) & 0xf0;
63 }
64 return (h & 0x0fffffff);
65 }
66
67 /*
68 * Hash function for symbol table lookup. Don't even think about changing
69 * this. It is specified by the GNU toolchain ABI.
70 */
71 Elf32_Word
_rtld_gnu_hash(const char * name)72 _rtld_gnu_hash(const char *name)
73 {
74 const unsigned char *p = (const unsigned char *) name;
75 uint_fast32_t h = 5381;
76 unsigned char c;
77
78 for (c = *p; c != '\0'; c = *++p)
79 h = h * 33 + c;
80 return (h & 0xffffffff);
81 }
82