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	Elf64_Addr *where, val;
50	Elf32_Addr *where32, val32;
51	Elf_Addr addend, addr;
52	Elf_Size rtype, symidx;
53	const Elf_Rel *rel;
54	const Elf_Rela *rela;
55
56	switch (reltype) {
57	case EF_RELOC_REL:
58		rel = (const Elf_Rel *)reldata;
59		where = (Elf_Addr *)(dest + relbase + rel->r_offset - dataoff);
60		addend = 0;
61		rtype = ELF_R_TYPE(rel->r_info);
62		symidx = ELF_R_SYM(rel->r_info);
63		break;
64	case EF_RELOC_RELA:
65		rela = (const Elf_Rela *)reldata;
66		where = (Elf_Addr *)(dest + relbase + rela->r_offset - dataoff);
67		addend = rela->r_addend;
68		rtype = ELF_R_TYPE(rela->r_info);
69		symidx = ELF_R_SYM(rela->r_info);
70		break;
71	default:
72		return (EINVAL);
73	}
74
75	if ((char *)where < (char *)dest || (char *)where >= (char *)dest + len)
76		return (0);
77
78	if (reltype == EF_RELOC_REL) {
79		/* Addend is 32 bit on 32 bit relocs */
80		switch (rtype) {
81		case R_X86_64_PC32:
82		case R_X86_64_32S:
83			addend = *(Elf32_Addr *)where;
84			break;
85		default:
86			addend = *where;
87			break;
88		}
89	}
90
91	switch (rtype) {
92	case R_X86_64_NONE:	/* none */
93		break;
94	case R_X86_64_64:	/* S + A */
95		addr = EF_SYMADDR(ef, symidx);
96		val = addr + addend;
97		*where = val;
98		break;
99	case R_X86_64_32S:	/* S + A sign extend */
100		addr = EF_SYMADDR(ef, symidx);
101		val32 = (Elf32_Addr)(addr + addend);
102		where32 = (Elf32_Addr *)where;
103		*where32 = val32;
104		break;
105	case R_X86_64_GLOB_DAT:	/* S */
106		addr = EF_SYMADDR(ef, symidx);
107		*where = addr;
108		break;
109	case R_X86_64_RELATIVE:	/* B + A */
110		addr = (Elf_Addr)addend + relbase;
111		val = addr;
112		*where = val;
113		break;
114	default:
115		warnx("unhandled relocation type %d", (int)rtype);
116	}
117	return (0);
118}
119