1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2019 John Baldwin <jhb@FreeBSD.org>
5 *
6 * This software was developed by SRI International and the University of
7 * Cambridge Computer Laboratory (Department of Computer Science and
8 * Technology) under DARPA contract HR0011-18-C-0016 ("ECATS"), as part of the
9 * DARPA SSITH research programme.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $FreeBSD$
33 */
34
35#include <sys/types.h>
36#include <machine/elf.h>
37
38#include <err.h>
39#include <errno.h>
40
41#include "ef.h"
42
43/*
44 * Apply relocations to the values we got from the file. `relbase' is the
45 * target relocation address of the section, and `dataoff' is the target
46 * relocation address of the data in `dest'.
47 */
48int
49ef_reloc(struct elf_file *ef, const void *reldata, int reltype, Elf_Off relbase,
50    Elf_Off dataoff, size_t len, void *dest)
51{
52	Elf_Addr *where, val;
53	const Elf_Rel *rel;
54	const Elf_Rela *rela;
55	Elf_Addr addend, addr;
56	Elf_Size rtype, symidx;
57
58	switch (reltype) {
59	case EF_RELOC_REL:
60		rel = (const Elf_Rel *)reldata;
61		where = (Elf_Addr *)((char *)dest + relbase + rel->r_offset -
62		    dataoff);
63		addend = 0;
64		rtype = ELF_R_TYPE(rel->r_info);
65		symidx = ELF_R_SYM(rel->r_info);
66		break;
67	case EF_RELOC_RELA:
68		rela = (const Elf_Rela *)reldata;
69		where = (Elf_Addr *)((char *)dest + relbase + rela->r_offset -
70		    dataoff);
71		addend = rela->r_addend;
72		rtype = ELF_R_TYPE(rela->r_info);
73		symidx = ELF_R_SYM(rela->r_info);
74		break;
75	default:
76		return (EINVAL);
77	}
78
79	if ((char *)where < (char *)dest || (char *)where >= (char *)dest + len)
80		return (0);
81
82	if (reltype == EF_RELOC_REL)
83		addend = *where;
84
85	switch (rtype) {
86#ifdef __LP64__
87	case R_MIPS_64:		/* S + A */
88#else
89	case R_MIPS_32:		/* S + A */
90#endif
91		addr = EF_SYMADDR(ef, symidx);
92		val = addr + addend;
93		*where = val;
94		break;
95	default:
96		warnx("unhandled relocation type %d", (int)rtype);
97	}
98	return (0);
99}
100