1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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
30 #include <sys/endian.h>
31
32 #include <err.h>
33 #include <errno.h>
34 #include <gelf.h>
35
36 #include "ef.h"
37
38 /*
39 * Apply relocations to the values obtained from the file. `relbase' is the
40 * target relocation address of the section, and `dataoff/len' is the region
41 * that is to be relocated, and has been copied to *dest
42 */
43 static int
ef_i386_reloc(struct elf_file * ef,const void * reldata,Elf_Type reltype,GElf_Addr relbase,GElf_Addr dataoff,size_t len,void * dest)44 ef_i386_reloc(struct elf_file *ef, const void *reldata, Elf_Type reltype,
45 GElf_Addr relbase, GElf_Addr dataoff, size_t len, void *dest)
46 {
47 char *where;
48 GElf_Addr addr, addend;
49 GElf_Size rtype, symidx;
50 const GElf_Rel *rel;
51 const GElf_Rela *rela;
52
53 switch (reltype) {
54 case ELF_T_REL:
55 rel = (const GElf_Rel *)reldata;
56 where = (char *)dest + (relbase + rel->r_offset - dataoff);
57 addend = 0;
58 rtype = GELF_R_TYPE(rel->r_info);
59 symidx = GELF_R_SYM(rel->r_info);
60 break;
61 case ELF_T_RELA:
62 rela = (const GElf_Rela *)reldata;
63 where = (char *)dest + (relbase + rela->r_offset - dataoff);
64 addend = rela->r_addend;
65 rtype = GELF_R_TYPE(rela->r_info);
66 symidx = GELF_R_SYM(rela->r_info);
67 break;
68 default:
69 return (EINVAL);
70 }
71
72 if (where < (char *)dest || where >= (char *)dest + len)
73 return (0);
74
75 if (reltype == ELF_T_REL)
76 addend = le32dec(where);
77
78 switch (rtype) {
79 case R_386_RELATIVE: /* B + A */
80 addr = relbase + addend;
81 le32enc(where, addr);
82 break;
83 case R_386_32: /* S + A - P */
84 addr = EF_SYMADDR(ef, symidx) + addend;
85 le32enc(where, addr);
86 break;
87 case R_386_GLOB_DAT: /* S */
88 addr = EF_SYMADDR(ef, symidx);
89 le32enc(where, addr);
90 break;
91 default:
92 warnx("unhandled relocation type %d", (int)rtype);
93 }
94 return (0);
95 }
96
97 ELF_RELOC(ELFCLASS32, ELFDATA2LSB, EM_386, ef_i386_reloc);
98