9dba198b0e
rather than relying on a trick that happens to work for the current relocation schemes. Also add some comments and improve variable naming.
118 lines
3.4 KiB
C
118 lines
3.4 KiB
C
/*-
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* Copyright (c) 2003 Jake Burkholder.
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* Copyright 1996-1998 John D. Polstra.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/types.h>
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#include <machine/elf.h>
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#include <err.h>
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#include <errno.h>
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#include <string.h>
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#include "ef.h"
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/*
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* Apply relocations to the values we got from the file. `relbase' is the
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* target relocation address of the section, and `dataoff' is the target
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* relocation address of the data in `dest'.
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*/
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int
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ef_reloc(struct elf_file *ef, const void *reldata, int reltype, Elf_Off relbase,
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Elf_Off dataoff, size_t len, void *dest)
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{
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Elf64_Addr *where, val;
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Elf32_Addr *where32, val32;
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Elf_Addr addend, addr;
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Elf_Word rtype, symidx;
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const Elf_Rel *rel;
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const Elf_Rela *rela;
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switch (reltype) {
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case EF_RELOC_REL:
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rel = (const Elf_Rel *)reldata;
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where = (Elf_Addr *)(dest + relbase + rel->r_offset - dataoff);
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addend = 0;
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rtype = ELF_R_TYPE(rel->r_info);
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symidx = ELF_R_SYM(rel->r_info);
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break;
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case EF_RELOC_RELA:
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rela = (const Elf_Rela *)reldata;
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where = (Elf_Addr *)(dest + relbase + rela->r_offset - dataoff);
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addend = rela->r_addend;
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rtype = ELF_R_TYPE(rela->r_info);
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symidx = ELF_R_SYM(rela->r_info);
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break;
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default:
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return (EINVAL);
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}
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if ((char *)where < (char *)dest || (char *)where >= (char *)dest + len)
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return (0);
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if (reltype == EF_RELOC_REL) {
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/* Addend is 32 bit on 32 bit relocs */
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switch (rtype) {
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case R_X86_64_PC32:
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case R_X86_64_32S:
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addend = *(Elf32_Addr *)where;
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break;
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default:
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addend = *where;
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break;
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}
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}
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switch (rtype) {
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case R_X86_64_NONE: /* none */
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break;
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case R_X86_64_64: /* S + A */
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addr = EF_SYMADDR(ef, symidx);
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val = addr + addend;
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*where = val;
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break;
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case R_X86_64_32S: /* S + A sign extend */
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addr = EF_SYMADDR(ef, symidx);
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val32 = (Elf32_Addr)(addr + addend);
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where32 = (Elf32_Addr *)where;
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*where32 = val32;
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break;
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case R_X86_64_GLOB_DAT: /* S */
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addr = EF_SYMADDR(ef, symidx);
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*where = addr;
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break;
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case R_X86_64_RELATIVE: /* B + A */
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addr = (Elf_Addr)addend + relbase;
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val = addr;
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*where = val;
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break;
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default:
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warnx("unhandled relocation type %d", (int)rtype);
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}
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return (0);
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}
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