NetBSD/libexec/ld.elf_so/hash.c

82 lines
2.7 KiB
C

/* $NetBSD: hash.c,v 1.1 2023/07/30 09:20:14 riastradh Exp $ */
/*
* Copyright 1996 John D. Polstra.
* Copyright 1996 Matt Thomas <matt@3am-software.com>
* Copyright 2002 Charles M. Hannum <root@ihack.net>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Polstra.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Dynamic linker for ELF.
*
* John Polstra <jdp@polstra.com>.
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: hash.c,v 1.1 2023/07/30 09:20:14 riastradh Exp $");
#endif /* not lint */
#include <stdint.h>
#include "hash.h"
/*
* SysV hash function for symbol table lookup. It is a slightly optimized
* version of the hash specified by the System V ABI.
*/
Elf32_Word
_rtld_sysv_hash(const char *name)
{
const unsigned char *p = (const unsigned char *) name;
Elf32_Word h = 0;
while (__predict_true(*p != '\0')) {
h = (h << 4) + *p++;
h ^= (h >> 24) & 0xf0;
}
return (h & 0x0fffffff);
}
/*
* Hash function for symbol table lookup. Don't even think about changing
* this. It is specified by the GNU toolchain ABI.
*/
Elf32_Word
_rtld_gnu_hash(const char *name)
{
const unsigned char *p = (const unsigned char *) name;
uint_fast32_t h = 5381;
unsigned char c;
for (c = *p; c != '\0'; c = *++p)
h = h * 33 + c;
return (h & 0xffffffff);
}