1 /* $NetBSD: lookup_elf32.c,v 1.3 2010/02/11 21:28:16 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
44 void * ELFNAMEEND(lookup_symbol)(const char *, void *, void *);
45
46 void *
ELFNAMEEND(lookup_symbol)47 ELFNAMEEND(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