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 */
45 int
ef_reloc(struct elf_file * ef,const void * reldata,int reltype,Elf_Off relbase,Elf_Off dataoff,size_t len,void * dest)46 ef_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