1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2003 Jake Burkholder.
5 * Copyright 1996-1998 John D. Polstra.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD$
30 */
31
32#include <sys/types.h>
33#include <machine/elf.h>
34
35#include <err.h>
36#include <errno.h>
37
38#include "ef.h"
39
40/*
41 * Apply relocations to the values we got from the file. `relbase' is the
42 * target relocation address of the section, and `dataoff' is the target
43 * relocation address of the data in `dest'.
44 */
45int
46ef_reloc(struct elf_file *ef, const void *reldata, int reltype, Elf_Off relbase,
47    Elf_Off dataoff, size_t len, void *_dest)
48{
49	Elf_Addr *where, addr, addend;
50	Elf_Size rtype, symidx;
51	const Elf_Rel *rel;
52	const Elf_Rela *rela;
53	char *dest = _dest;
54
55	switch (reltype) {
56	case EF_RELOC_REL:
57		rel = (const Elf_Rel *)reldata;
58		where = (Elf_Addr *)(dest + relbase + rel->r_offset - dataoff);
59		addend = 0;
60		rtype = ELF_R_TYPE(rel->r_info);
61		symidx = ELF_R_SYM(rel->r_info);
62		break;
63	case EF_RELOC_RELA:
64		rela = (const Elf_Rela *)reldata;
65		where = (Elf_Addr *)(dest + relbase + rela->r_offset - dataoff);
66		addend = rela->r_addend;
67		rtype = ELF_R_TYPE(rela->r_info);
68		symidx = ELF_R_SYM(rela->r_info);
69		break;
70	default:
71		return (EINVAL);
72	}
73
74	if ((char *)where < (char *)dest || (char *)where >= (char *)dest + len)
75		return (0);
76
77	if (reltype == EF_RELOC_REL)
78		addend = *where;
79
80	switch (rtype) {
81	case R_386_RELATIVE:	/* A + B */
82		addr = (Elf_Addr)addend + relbase;
83		*where = addr;
84		break;
85	case R_386_32:	/* S + A - P */
86		addr = EF_SYMADDR(ef, symidx);
87		addr += addend;
88		*where = addr;
89		break;
90	case R_386_GLOB_DAT:	/* S */
91		addr = EF_SYMADDR(ef, symidx);
92		*where = addr;
93		break;
94	default:
95		warnx("unhandled relocation type %d", (int)rtype);
96	}
97	return (0);
98}
99