125 lines
2.5 KiB
Go
125 lines
2.5 KiB
Go
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// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Parsing of ELF executables (Linux, FreeBSD, and so on).
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package objfile
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import (
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"debug/dwarf"
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"debug/elf"
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"encoding/binary"
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"fmt"
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"os"
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)
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type elfFile struct {
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elf *elf.File
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}
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func openElf(r *os.File) (rawFile, error) {
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f, err := elf.NewFile(r)
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if err != nil {
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return nil, err
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}
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return &elfFile{f}, nil
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}
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func (f *elfFile) symbols() ([]Sym, error) {
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elfSyms, err := f.elf.Symbols()
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if err != nil {
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return nil, err
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}
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var syms []Sym
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for _, s := range elfSyms {
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sym := Sym{Addr: s.Value, Name: s.Name, Size: int64(s.Size), Code: '?'}
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switch s.Section {
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case elf.SHN_UNDEF:
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sym.Code = 'U'
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case elf.SHN_COMMON:
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sym.Code = 'B'
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default:
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i := int(s.Section)
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if i < 0 || i >= len(f.elf.Sections) {
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break
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}
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sect := f.elf.Sections[i]
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switch sect.Flags & (elf.SHF_WRITE | elf.SHF_ALLOC | elf.SHF_EXECINSTR) {
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case elf.SHF_ALLOC | elf.SHF_EXECINSTR:
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sym.Code = 'T'
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case elf.SHF_ALLOC:
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sym.Code = 'R'
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case elf.SHF_ALLOC | elf.SHF_WRITE:
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sym.Code = 'D'
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}
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}
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if elf.ST_BIND(s.Info) == elf.STB_LOCAL {
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sym.Code += 'a' - 'A'
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}
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syms = append(syms, sym)
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}
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return syms, nil
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}
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func (f *elfFile) pcln() (textStart uint64, symtab, pclntab []byte, err error) {
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if sect := f.elf.Section(".text"); sect != nil {
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textStart = sect.Addr
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}
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if sect := f.elf.Section(".gosymtab"); sect != nil {
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if symtab, err = sect.Data(); err != nil {
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return 0, nil, nil, err
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}
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}
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if sect := f.elf.Section(".gopclntab"); sect != nil {
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if pclntab, err = sect.Data(); err != nil {
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return 0, nil, nil, err
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}
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}
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return textStart, symtab, pclntab, nil
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}
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func (f *elfFile) text() (textStart uint64, text []byte, err error) {
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sect := f.elf.Section(".text")
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if sect == nil {
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return 0, nil, fmt.Errorf("text section not found")
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}
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textStart = sect.Addr
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text, err = sect.Data()
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return
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}
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func (f *elfFile) goarch() string {
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switch f.elf.Machine {
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case elf.EM_386:
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return "386"
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case elf.EM_X86_64:
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return "amd64"
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case elf.EM_ARM:
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return "arm"
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case elf.EM_PPC64:
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if f.elf.ByteOrder == binary.LittleEndian {
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return "ppc64le"
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}
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return "ppc64"
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case elf.EM_S390:
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return "s390x"
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}
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return ""
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}
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func (f *elfFile) loadAddress() (uint64, error) {
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for _, p := range f.elf.Progs {
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if p.Type == elf.PT_LOAD {
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return p.Vaddr, nil
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}
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}
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return 0, fmt.Errorf("unknown load address")
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}
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func (f *elfFile) dwarf() (*dwarf.Data, error) {
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return f.elf.DWARF()
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}
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