1/* $NetBSD: lookup_elf32.c,v 1.2 2010/02/10 23:33:56 martin Exp $ */
2
3/*-
4 * Copyright (c) 2010 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Martin Husemann.
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 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/* If not included by lookup_elf64.c, ELFSIZE won't be defined. */
33#ifndef ELFSIZE
34#define	ELFSIZE	32
35#endif
36
37#include <lib/libkern/libkern.h>
38#include <sys/param.h>
39#include <sys/exec_elf.h>
40
41#if ((ELFSIZE == 32) && defined(BOOT_ELF32)) || \
42    ((ELFSIZE == 64) && defined(BOOT_ELF64))
43
44void * ELFNAMEEND(lookup_symbol)(const char *, void *, void *);
45
46void *
47ELFNAMEEND(lookup_symbol)(const char *symname, void *sstab, void *estab)
48{
49	Elf_Ehdr *elf;
50	Elf_Shdr *shp;
51	Elf_Sym *symtab_start, *symtab_end, *sp;
52	char *strtab_start, *strtab_end;
53	int i, j;
54
55	elf = sstab;
56	if (elf->e_shoff == 0)
57		return NULL;
58
59	switch (elf->e_machine) {
60	ELFDEFNNAME(MACHDEP_ID_CASES)
61	default:
62		return NULL;
63	}
64
65	symtab_start = symtab_end = NULL;
66	strtab_start = strtab_end = NULL;
67
68	shp = (Elf_Shdr *)((char *)sstab + elf->e_shoff);
69	for (i = 0; i < elf->e_shnum; i++) {
70		if (shp[i].sh_type != SHT_SYMTAB)
71			continue;
72		if (shp[i].sh_offset == 0)
73			continue;
74		symtab_start = (Elf_Sym*)((char*)sstab + shp[i].sh_offset);
75		symtab_end = (Elf_Sym*)((char*)sstab + shp[i].sh_offset
76			+ shp[i].sh_size);
77		j = shp[i].sh_link;
78		if (shp[j].sh_offset == 0)
79			continue;
80		strtab_start = (char*)sstab + shp[j].sh_offset;
81		strtab_end = (char*)sstab + shp[j].sh_offset + shp[j].sh_size;
82		break;
83	}
84
85	if (!symtab_start || !strtab_start)
86		return NULL;
87
88	for (sp = symtab_start; sp < symtab_end; sp++)
89		if (sp->st_name != 0 &&
90		    strcmp(strtab_start + sp->st_name, symname) == 0)
91			return (void*)(uintptr_t)sp->st_value;
92
93	return NULL;
94}
95
96#endif /* (ELFSIZE == 32 && BOOT_ELF32) || (ELFSIZE == 64 && BOOT_ELF64) */
97