ef_i386.c revision 186826 
1/*-
2 * Copyright (c) 2003 Jake Burkholder.
3 * Copyright 1996-1998 John D. Polstra.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD: head/usr.sbin/kldxref/ef_i386.c 186826 2009-01-06 14:21:17Z luigi $
28 */
29
30#include <sys/types.h>
31#include <machine/elf.h>
32
33#include <err.h>
34#include <errno.h>
35#include <string.h>
36
37#include "ef.h"
38
39/*
40 * Apply relocations to the values we got from the file. `relbase' is the
41 * target relocation address of the section, and `dataoff' is the target
42 * relocation address of the data in `dest'.
43 */
44int
45ef_reloc(struct elf_file *ef, const void *reldata, int reltype, Elf_Off relbase,
46    Elf_Off dataoff, size_t len, void *_dest)
47{
48	Elf_Addr *where, addr, addend;
49	Elf_Size rtype, symidx;
50	const Elf_Rel *rel;
51	const Elf_Rela *rela;
52	char *dest = _dest;
53
54	switch (reltype) {
55	case EF_RELOC_REL:
56		rel = (const Elf_Rel *)reldata;
57		where = (Elf_Addr *)(dest + relbase + rel->r_offset - dataoff);
58		addend = 0;
59		rtype = ELF_R_TYPE(rel->r_info);
60		symidx = ELF_R_SYM(rel->r_info);
61		break;
62	case EF_RELOC_RELA:
63		rela = (const Elf_Rela *)reldata;
64		where = (Elf_Addr *)(dest + relbase + rela->r_offset - dataoff);
65		addend = rela->r_addend;
66		rtype = ELF_R_TYPE(rela->r_info);
67		symidx = ELF_R_SYM(rela->r_info);
68		break;
69	default:
70		return (EINVAL);
71	}
72
73	if ((char *)where < (char *)dest || (char *)where >= (char *)dest + len)
74		return (0);
75
76	if (reltype == EF_RELOC_REL)
77		addend = *where;
78
79	switch (rtype) {
80	case R_386_RELATIVE:	/* A + B */
81		addr = (Elf_Addr)addend + relbase;
82		*where = addr;
83		break;
84	case R_386_32:	/* S + A - P */
85		addr = EF_SYMADDR(ef, symidx);
86		addr += addend;
87		*where = addr;
88		break;
89	case R_386_GLOB_DAT:	/* S */
90		addr = EF_SYMADDR(ef, symidx);
91		*where = addr;
92		break;
93	default:
94		warnx("unhandled relocation type %d", (int)rtype);
95	}
96	return (0);
97}
98