mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-11 19:49:32 +00:00
1089 lines
26 KiB
Go
1089 lines
26 KiB
Go
// Copyright 2009 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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// Package elf implements access to ELF object files.
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package elf
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import (
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"bytes"
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"debug/dwarf"
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"encoding/binary"
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"errors"
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"fmt"
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"io"
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"os"
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)
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// TODO: error reporting detail
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/*
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* Internal ELF representation
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*/
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// A FileHeader represents an ELF file header.
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type FileHeader struct {
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Class Class
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Data Data
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Version Version
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OSABI OSABI
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ABIVersion uint8
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ByteOrder binary.ByteOrder
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Type Type
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Machine Machine
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Entry uint64
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}
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// A File represents an open ELF file.
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type File struct {
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FileHeader
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Sections []*Section
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Progs []*Prog
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closer io.Closer
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gnuNeed []verneed
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gnuVersym []byte
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}
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// A SectionHeader represents a single ELF section header.
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type SectionHeader struct {
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Name string
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Type SectionType
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Flags SectionFlag
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Addr uint64
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Offset uint64
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Size uint64
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Link uint32
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Info uint32
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Addralign uint64
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Entsize uint64
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}
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// A Section represents a single section in an ELF file.
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type Section struct {
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SectionHeader
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// Embed ReaderAt for ReadAt method.
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// Do not embed SectionReader directly
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// to avoid having Read and Seek.
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// If a client wants Read and Seek it must use
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// Open() to avoid fighting over the seek offset
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// with other clients.
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io.ReaderAt
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sr *io.SectionReader
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}
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// Data reads and returns the contents of the ELF section.
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func (s *Section) Data() ([]byte, error) {
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dat := make([]byte, s.sr.Size())
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n, err := s.sr.ReadAt(dat, 0)
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if n == len(dat) {
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err = nil
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}
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return dat[0:n], err
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}
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// stringTable reads and returns the string table given by the
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// specified link value.
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func (f *File) stringTable(link uint32) ([]byte, error) {
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if link <= 0 || link >= uint32(len(f.Sections)) {
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return nil, errors.New("section has invalid string table link")
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}
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return f.Sections[link].Data()
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}
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// Open returns a new ReadSeeker reading the ELF section.
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func (s *Section) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) }
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// A ProgHeader represents a single ELF program header.
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type ProgHeader struct {
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Type ProgType
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Flags ProgFlag
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Off uint64
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Vaddr uint64
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Paddr uint64
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Filesz uint64
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Memsz uint64
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Align uint64
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}
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// A Prog represents a single ELF program header in an ELF binary.
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type Prog struct {
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ProgHeader
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// Embed ReaderAt for ReadAt method.
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// Do not embed SectionReader directly
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// to avoid having Read and Seek.
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// If a client wants Read and Seek it must use
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// Open() to avoid fighting over the seek offset
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// with other clients.
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io.ReaderAt
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sr *io.SectionReader
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}
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// Open returns a new ReadSeeker reading the ELF program body.
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func (p *Prog) Open() io.ReadSeeker { return io.NewSectionReader(p.sr, 0, 1<<63-1) }
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// A Symbol represents an entry in an ELF symbol table section.
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type Symbol struct {
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Name string
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Info, Other byte
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Section SectionIndex
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Value, Size uint64
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}
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/*
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* ELF reader
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*/
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type FormatError struct {
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off int64
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msg string
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val interface{}
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}
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func (e *FormatError) Error() string {
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msg := e.msg
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if e.val != nil {
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msg += fmt.Sprintf(" '%v' ", e.val)
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}
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msg += fmt.Sprintf("in record at byte %#x", e.off)
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return msg
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}
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// Open opens the named file using os.Open and prepares it for use as an ELF binary.
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func Open(name string) (*File, error) {
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f, err := os.Open(name)
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if err != nil {
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return nil, err
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}
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ff, err := NewFile(f)
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if err != nil {
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f.Close()
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return nil, err
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}
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ff.closer = f
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return ff, nil
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}
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// Close closes the File.
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// If the File was created using NewFile directly instead of Open,
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// Close has no effect.
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func (f *File) Close() error {
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var err error
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if f.closer != nil {
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err = f.closer.Close()
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f.closer = nil
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}
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return err
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}
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// SectionByType returns the first section in f with the
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// given type, or nil if there is no such section.
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func (f *File) SectionByType(typ SectionType) *Section {
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for _, s := range f.Sections {
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if s.Type == typ {
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return s
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}
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}
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return nil
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}
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// NewFile creates a new File for accessing an ELF binary in an underlying reader.
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// The ELF binary is expected to start at position 0 in the ReaderAt.
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func NewFile(r io.ReaderAt) (*File, error) {
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sr := io.NewSectionReader(r, 0, 1<<63-1)
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// Read and decode ELF identifier
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var ident [16]uint8
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if _, err := r.ReadAt(ident[0:], 0); err != nil {
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return nil, err
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}
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if ident[0] != '\x7f' || ident[1] != 'E' || ident[2] != 'L' || ident[3] != 'F' {
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return nil, &FormatError{0, "bad magic number", ident[0:4]}
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}
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f := new(File)
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f.Class = Class(ident[EI_CLASS])
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switch f.Class {
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case ELFCLASS32:
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case ELFCLASS64:
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// ok
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default:
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return nil, &FormatError{0, "unknown ELF class", f.Class}
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}
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f.Data = Data(ident[EI_DATA])
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switch f.Data {
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case ELFDATA2LSB:
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f.ByteOrder = binary.LittleEndian
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case ELFDATA2MSB:
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f.ByteOrder = binary.BigEndian
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default:
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return nil, &FormatError{0, "unknown ELF data encoding", f.Data}
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}
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f.Version = Version(ident[EI_VERSION])
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if f.Version != EV_CURRENT {
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return nil, &FormatError{0, "unknown ELF version", f.Version}
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}
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f.OSABI = OSABI(ident[EI_OSABI])
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f.ABIVersion = ident[EI_ABIVERSION]
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// Read ELF file header
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var phoff int64
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var phentsize, phnum int
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var shoff int64
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var shentsize, shnum, shstrndx int
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shstrndx = -1
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switch f.Class {
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case ELFCLASS32:
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hdr := new(Header32)
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sr.Seek(0, os.SEEK_SET)
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if err := binary.Read(sr, f.ByteOrder, hdr); err != nil {
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return nil, err
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}
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f.Type = Type(hdr.Type)
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f.Machine = Machine(hdr.Machine)
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f.Entry = uint64(hdr.Entry)
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if v := Version(hdr.Version); v != f.Version {
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return nil, &FormatError{0, "mismatched ELF version", v}
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}
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phoff = int64(hdr.Phoff)
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phentsize = int(hdr.Phentsize)
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phnum = int(hdr.Phnum)
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shoff = int64(hdr.Shoff)
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shentsize = int(hdr.Shentsize)
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shnum = int(hdr.Shnum)
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shstrndx = int(hdr.Shstrndx)
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case ELFCLASS64:
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hdr := new(Header64)
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sr.Seek(0, os.SEEK_SET)
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if err := binary.Read(sr, f.ByteOrder, hdr); err != nil {
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return nil, err
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}
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f.Type = Type(hdr.Type)
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f.Machine = Machine(hdr.Machine)
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f.Entry = uint64(hdr.Entry)
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if v := Version(hdr.Version); v != f.Version {
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return nil, &FormatError{0, "mismatched ELF version", v}
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}
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phoff = int64(hdr.Phoff)
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phentsize = int(hdr.Phentsize)
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phnum = int(hdr.Phnum)
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shoff = int64(hdr.Shoff)
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shentsize = int(hdr.Shentsize)
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shnum = int(hdr.Shnum)
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shstrndx = int(hdr.Shstrndx)
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}
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if shnum > 0 && shoff > 0 && (shstrndx < 0 || shstrndx >= shnum) {
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return nil, &FormatError{0, "invalid ELF shstrndx", shstrndx}
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}
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// Read program headers
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f.Progs = make([]*Prog, phnum)
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for i := 0; i < phnum; i++ {
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off := phoff + int64(i)*int64(phentsize)
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sr.Seek(off, os.SEEK_SET)
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p := new(Prog)
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switch f.Class {
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case ELFCLASS32:
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ph := new(Prog32)
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if err := binary.Read(sr, f.ByteOrder, ph); err != nil {
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return nil, err
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}
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p.ProgHeader = ProgHeader{
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Type: ProgType(ph.Type),
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Flags: ProgFlag(ph.Flags),
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Off: uint64(ph.Off),
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Vaddr: uint64(ph.Vaddr),
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Paddr: uint64(ph.Paddr),
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Filesz: uint64(ph.Filesz),
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Memsz: uint64(ph.Memsz),
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Align: uint64(ph.Align),
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}
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case ELFCLASS64:
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ph := new(Prog64)
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if err := binary.Read(sr, f.ByteOrder, ph); err != nil {
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return nil, err
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}
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p.ProgHeader = ProgHeader{
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Type: ProgType(ph.Type),
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Flags: ProgFlag(ph.Flags),
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Off: uint64(ph.Off),
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Vaddr: uint64(ph.Vaddr),
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Paddr: uint64(ph.Paddr),
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Filesz: uint64(ph.Filesz),
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Memsz: uint64(ph.Memsz),
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Align: uint64(ph.Align),
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}
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}
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p.sr = io.NewSectionReader(r, int64(p.Off), int64(p.Filesz))
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p.ReaderAt = p.sr
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f.Progs[i] = p
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}
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// Read section headers
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f.Sections = make([]*Section, shnum)
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names := make([]uint32, shnum)
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for i := 0; i < shnum; i++ {
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off := shoff + int64(i)*int64(shentsize)
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sr.Seek(off, os.SEEK_SET)
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s := new(Section)
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switch f.Class {
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case ELFCLASS32:
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sh := new(Section32)
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if err := binary.Read(sr, f.ByteOrder, sh); err != nil {
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return nil, err
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}
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names[i] = sh.Name
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s.SectionHeader = SectionHeader{
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Type: SectionType(sh.Type),
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Flags: SectionFlag(sh.Flags),
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Addr: uint64(sh.Addr),
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Offset: uint64(sh.Off),
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Size: uint64(sh.Size),
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Link: uint32(sh.Link),
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Info: uint32(sh.Info),
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Addralign: uint64(sh.Addralign),
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Entsize: uint64(sh.Entsize),
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}
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case ELFCLASS64:
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sh := new(Section64)
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if err := binary.Read(sr, f.ByteOrder, sh); err != nil {
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return nil, err
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}
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names[i] = sh.Name
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s.SectionHeader = SectionHeader{
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Type: SectionType(sh.Type),
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Flags: SectionFlag(sh.Flags),
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Offset: uint64(sh.Off),
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Size: uint64(sh.Size),
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Addr: uint64(sh.Addr),
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Link: uint32(sh.Link),
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Info: uint32(sh.Info),
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Addralign: uint64(sh.Addralign),
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Entsize: uint64(sh.Entsize),
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}
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}
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s.sr = io.NewSectionReader(r, int64(s.Offset), int64(s.Size))
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s.ReaderAt = s.sr
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f.Sections[i] = s
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}
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if len(f.Sections) == 0 {
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return f, nil
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}
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// Load section header string table.
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shstrtab, err := f.Sections[shstrndx].Data()
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if err != nil {
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return nil, err
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}
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for i, s := range f.Sections {
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var ok bool
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s.Name, ok = getString(shstrtab, int(names[i]))
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if !ok {
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return nil, &FormatError{shoff + int64(i*shentsize), "bad section name index", names[i]}
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}
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}
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return f, nil
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}
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// getSymbols returns a slice of Symbols from parsing the symbol table
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// with the given type, along with the associated string table.
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func (f *File) getSymbols(typ SectionType) ([]Symbol, []byte, error) {
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switch f.Class {
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case ELFCLASS64:
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return f.getSymbols64(typ)
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case ELFCLASS32:
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return f.getSymbols32(typ)
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}
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return nil, nil, errors.New("not implemented")
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}
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// ErrNoSymbols is returned by File.Symbols and File.DynamicSymbols
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// if there is no such section in the File.
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var ErrNoSymbols = errors.New("no symbol section")
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func (f *File) getSymbols32(typ SectionType) ([]Symbol, []byte, error) {
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symtabSection := f.SectionByType(typ)
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if symtabSection == nil {
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return nil, nil, ErrNoSymbols
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}
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data, err := symtabSection.Data()
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if err != nil {
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return nil, nil, errors.New("cannot load symbol section")
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}
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symtab := bytes.NewReader(data)
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if symtab.Len()%Sym32Size != 0 {
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return nil, nil, errors.New("length of symbol section is not a multiple of SymSize")
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}
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strdata, err := f.stringTable(symtabSection.Link)
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if err != nil {
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return nil, nil, errors.New("cannot load string table section")
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}
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// The first entry is all zeros.
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var skip [Sym32Size]byte
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symtab.Read(skip[:])
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symbols := make([]Symbol, symtab.Len()/Sym32Size)
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i := 0
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var sym Sym32
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for symtab.Len() > 0 {
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binary.Read(symtab, f.ByteOrder, &sym)
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str, _ := getString(strdata, int(sym.Name))
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symbols[i].Name = str
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symbols[i].Info = sym.Info
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symbols[i].Other = sym.Other
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symbols[i].Section = SectionIndex(sym.Shndx)
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symbols[i].Value = uint64(sym.Value)
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symbols[i].Size = uint64(sym.Size)
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i++
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}
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return symbols, strdata, nil
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}
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func (f *File) getSymbols64(typ SectionType) ([]Symbol, []byte, error) {
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symtabSection := f.SectionByType(typ)
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if symtabSection == nil {
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return nil, nil, ErrNoSymbols
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}
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data, err := symtabSection.Data()
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if err != nil {
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return nil, nil, errors.New("cannot load symbol section")
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}
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symtab := bytes.NewReader(data)
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if symtab.Len()%Sym64Size != 0 {
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return nil, nil, errors.New("length of symbol section is not a multiple of Sym64Size")
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}
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strdata, err := f.stringTable(symtabSection.Link)
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if err != nil {
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return nil, nil, errors.New("cannot load string table section")
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}
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// The first entry is all zeros.
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var skip [Sym64Size]byte
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symtab.Read(skip[:])
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symbols := make([]Symbol, symtab.Len()/Sym64Size)
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i := 0
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var sym Sym64
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for symtab.Len() > 0 {
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binary.Read(symtab, f.ByteOrder, &sym)
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str, _ := getString(strdata, int(sym.Name))
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symbols[i].Name = str
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symbols[i].Info = sym.Info
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symbols[i].Other = sym.Other
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symbols[i].Section = SectionIndex(sym.Shndx)
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symbols[i].Value = sym.Value
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symbols[i].Size = sym.Size
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i++
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}
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return symbols, strdata, nil
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}
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// getString extracts a string from an ELF string table.
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func getString(section []byte, start int) (string, bool) {
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if start < 0 || start >= len(section) {
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return "", false
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}
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for end := start; end < len(section); end++ {
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if section[end] == 0 {
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return string(section[start:end]), true
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}
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}
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return "", false
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}
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// Section returns a section with the given name, or nil if no such
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// section exists.
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func (f *File) Section(name string) *Section {
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for _, s := range f.Sections {
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if s.Name == name {
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return s
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}
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}
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return nil
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}
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|
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// applyRelocations applies relocations to dst. rels is a relocations section
|
|
// in RELA format.
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func (f *File) applyRelocations(dst []byte, rels []byte) error {
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if f.Class == ELFCLASS64 && f.Machine == EM_X86_64 {
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return f.applyRelocationsAMD64(dst, rels)
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}
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if f.Class == ELFCLASS32 && f.Machine == EM_386 {
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return f.applyRelocations386(dst, rels)
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}
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if f.Class == ELFCLASS64 && f.Machine == EM_AARCH64 {
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return f.applyRelocationsARM64(dst, rels)
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|
}
|
|
if f.Class == ELFCLASS32 && f.Machine == EM_PPC {
|
|
return f.applyRelocationsPPC(dst, rels)
|
|
}
|
|
if f.Class == ELFCLASS64 && f.Machine == EM_PPC64 {
|
|
return f.applyRelocationsPPC64(dst, rels)
|
|
}
|
|
if f.Class == ELFCLASS64 && f.Machine == EM_S390 {
|
|
return f.applyRelocationsS390x(dst, rels)
|
|
}
|
|
|
|
return errors.New("not implemented")
|
|
}
|
|
|
|
func (f *File) applyRelocationsAMD64(dst []byte, rels []byte) error {
|
|
// 24 is the size of Rela64.
|
|
if len(rels)%24 != 0 {
|
|
return errors.New("length of relocation section is not a multiple of 24")
|
|
}
|
|
|
|
symbols, _, err := f.getSymbols(SHT_SYMTAB)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
b := bytes.NewReader(rels)
|
|
var rela Rela64
|
|
|
|
for b.Len() > 0 {
|
|
binary.Read(b, f.ByteOrder, &rela)
|
|
symNo := rela.Info >> 32
|
|
t := R_X86_64(rela.Info & 0xffff)
|
|
|
|
if symNo == 0 || symNo > uint64(len(symbols)) {
|
|
continue
|
|
}
|
|
sym := &symbols[symNo-1]
|
|
if SymType(sym.Info&0xf) != STT_SECTION {
|
|
// We don't handle non-section relocations for now.
|
|
continue
|
|
}
|
|
|
|
// There are relocations, so this must be a normal
|
|
// object file, and we only look at section symbols,
|
|
// so we assume that the symbol value is 0.
|
|
|
|
switch t {
|
|
case R_X86_64_64:
|
|
if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 {
|
|
continue
|
|
}
|
|
f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], uint64(rela.Addend))
|
|
case R_X86_64_32:
|
|
if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 {
|
|
continue
|
|
}
|
|
f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], uint32(rela.Addend))
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (f *File) applyRelocations386(dst []byte, rels []byte) error {
|
|
// 8 is the size of Rel32.
|
|
if len(rels)%8 != 0 {
|
|
return errors.New("length of relocation section is not a multiple of 8")
|
|
}
|
|
|
|
symbols, _, err := f.getSymbols(SHT_SYMTAB)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
b := bytes.NewReader(rels)
|
|
var rel Rel32
|
|
|
|
for b.Len() > 0 {
|
|
binary.Read(b, f.ByteOrder, &rel)
|
|
symNo := rel.Info >> 8
|
|
t := R_386(rel.Info & 0xff)
|
|
|
|
if symNo == 0 || symNo > uint32(len(symbols)) {
|
|
continue
|
|
}
|
|
sym := &symbols[symNo-1]
|
|
|
|
if t == R_386_32 {
|
|
if rel.Off+4 >= uint32(len(dst)) {
|
|
continue
|
|
}
|
|
val := f.ByteOrder.Uint32(dst[rel.Off : rel.Off+4])
|
|
val += uint32(sym.Value)
|
|
f.ByteOrder.PutUint32(dst[rel.Off:rel.Off+4], val)
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (f *File) applyRelocationsARM64(dst []byte, rels []byte) error {
|
|
// 24 is the size of Rela64.
|
|
if len(rels)%24 != 0 {
|
|
return errors.New("length of relocation section is not a multiple of 24")
|
|
}
|
|
|
|
symbols, _, err := f.getSymbols(SHT_SYMTAB)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
b := bytes.NewReader(rels)
|
|
var rela Rela64
|
|
|
|
for b.Len() > 0 {
|
|
binary.Read(b, f.ByteOrder, &rela)
|
|
symNo := rela.Info >> 32
|
|
t := R_AARCH64(rela.Info & 0xffff)
|
|
|
|
if symNo == 0 || symNo > uint64(len(symbols)) {
|
|
continue
|
|
}
|
|
sym := &symbols[symNo-1]
|
|
if SymType(sym.Info&0xf) != STT_SECTION {
|
|
// We don't handle non-section relocations for now.
|
|
continue
|
|
}
|
|
|
|
// There are relocations, so this must be a normal
|
|
// object file, and we only look at section symbols,
|
|
// so we assume that the symbol value is 0.
|
|
|
|
switch t {
|
|
case R_AARCH64_ABS64:
|
|
if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 {
|
|
continue
|
|
}
|
|
f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], uint64(rela.Addend))
|
|
case R_AARCH64_ABS32:
|
|
if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 {
|
|
continue
|
|
}
|
|
f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], uint32(rela.Addend))
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (f *File) applyRelocationsPPC(dst []byte, rels []byte) error {
|
|
// 12 is the size of Rela32.
|
|
if len(rels)%12 != 0 {
|
|
return errors.New("length of relocation section is not a multiple of 12")
|
|
}
|
|
|
|
symbols, _, err := f.getSymbols(SHT_SYMTAB)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
b := bytes.NewReader(rels)
|
|
var rela Rela32
|
|
|
|
for b.Len() > 0 {
|
|
binary.Read(b, f.ByteOrder, &rela)
|
|
symNo := rela.Info >> 8
|
|
t := R_PPC(rela.Info & 0xff)
|
|
|
|
if symNo == 0 || symNo > uint32(len(symbols)) {
|
|
continue
|
|
}
|
|
sym := &symbols[symNo-1]
|
|
if SymType(sym.Info&0xf) != STT_SECTION {
|
|
// We don't handle non-section relocations for now.
|
|
continue
|
|
}
|
|
|
|
switch t {
|
|
case R_PPC_ADDR32:
|
|
if rela.Off+4 >= uint32(len(dst)) || rela.Addend < 0 {
|
|
continue
|
|
}
|
|
f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], uint32(rela.Addend))
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (f *File) applyRelocationsPPC64(dst []byte, rels []byte) error {
|
|
// 24 is the size of Rela64.
|
|
if len(rels)%24 != 0 {
|
|
return errors.New("length of relocation section is not a multiple of 24")
|
|
}
|
|
|
|
symbols, _, err := f.getSymbols(SHT_SYMTAB)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
b := bytes.NewReader(rels)
|
|
var rela Rela64
|
|
|
|
for b.Len() > 0 {
|
|
binary.Read(b, f.ByteOrder, &rela)
|
|
symNo := rela.Info >> 32
|
|
t := R_PPC64(rela.Info & 0xffff)
|
|
|
|
if symNo == 0 || symNo > uint64(len(symbols)) {
|
|
continue
|
|
}
|
|
sym := &symbols[symNo-1]
|
|
if SymType(sym.Info&0xf) != STT_SECTION {
|
|
// We don't handle non-section relocations for now.
|
|
continue
|
|
}
|
|
|
|
switch t {
|
|
case R_PPC64_ADDR64:
|
|
if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 {
|
|
continue
|
|
}
|
|
f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], uint64(rela.Addend))
|
|
case R_PPC64_ADDR32:
|
|
if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 {
|
|
continue
|
|
}
|
|
f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], uint32(rela.Addend))
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (f *File) applyRelocationsS390x(dst []byte, rels []byte) error {
|
|
// 24 is the size of Rela64.
|
|
if len(rels)%24 != 0 {
|
|
return errors.New("length of relocation section is not a multiple of 24")
|
|
}
|
|
|
|
symbols, _, err := f.getSymbols(SHT_SYMTAB)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
b := bytes.NewBuffer(rels)
|
|
var rela Rela64
|
|
|
|
for b.Len() > 0 {
|
|
binary.Read(b, f.ByteOrder, &rela)
|
|
symNo := rela.Info >> 32
|
|
t := R_390(rela.Info & 0xffff)
|
|
|
|
if symNo == 0 || symNo > uint64(len(symbols)) {
|
|
continue
|
|
}
|
|
sym := &symbols[symNo-1]
|
|
|
|
switch t {
|
|
case R_390_64:
|
|
if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 {
|
|
continue
|
|
}
|
|
f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], uint64(rela.Addend)+uint64(sym.Value))
|
|
case R_390_32:
|
|
if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 {
|
|
continue
|
|
}
|
|
f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], uint32(rela.Addend)+uint32(sym.Value))
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (f *File) DWARF() (*dwarf.Data, error) {
|
|
// There are many other DWARF sections, but these
|
|
// are the required ones, and the debug/dwarf package
|
|
// does not use the others, so don't bother loading them.
|
|
var names = [...]string{"abbrev", "info", "line", "ranges", "str"}
|
|
var dat [len(names)][]byte
|
|
for i, name := range names {
|
|
name = ".debug_" + name
|
|
s := f.Section(name)
|
|
if s == nil {
|
|
continue
|
|
}
|
|
b, err := s.Data()
|
|
if err != nil && uint64(len(b)) < s.Size {
|
|
return nil, err
|
|
}
|
|
dat[i] = b
|
|
}
|
|
|
|
// If there's a relocation table for .debug_info, we have to process it
|
|
// now otherwise the data in .debug_info is invalid for x86-64 objects.
|
|
rela := f.Section(".rela.debug_info")
|
|
if rela != nil && rela.Type == SHT_RELA && (f.Machine == EM_X86_64 || f.Machine == EM_AARCH64 || f.Machine == EM_PPC || f.Machine == EM_PPC64 || f.Machine == EM_S390) {
|
|
data, err := rela.Data()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
err = f.applyRelocations(dat[1], data)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
// When using clang we need to process relocations even for 386.
|
|
rel := f.Section(".rel.debug_info")
|
|
if rel != nil && rel.Type == SHT_REL && f.Machine == EM_386 {
|
|
data, err := rel.Data()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
err = f.applyRelocations(dat[1], data)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
abbrev, info, line, ranges, str := dat[0], dat[1], dat[2], dat[3], dat[4]
|
|
d, err := dwarf.New(abbrev, nil, nil, info, line, nil, ranges, str)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Look for DWARF4 .debug_types sections.
|
|
for i, s := range f.Sections {
|
|
if s.Name == ".debug_types" {
|
|
b, err := s.Data()
|
|
if err != nil && uint64(len(b)) < s.Size {
|
|
return nil, err
|
|
}
|
|
|
|
for _, r := range f.Sections {
|
|
if r.Type != SHT_RELA && r.Type != SHT_REL {
|
|
continue
|
|
}
|
|
if int(r.Info) != i {
|
|
continue
|
|
}
|
|
rd, err := r.Data()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
err = f.applyRelocations(b, rd)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
err = d.AddTypes(fmt.Sprintf("types-%d", i), b)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
}
|
|
|
|
return d, nil
|
|
}
|
|
|
|
// Symbols returns the symbol table for f. The symbols will be listed in the order
|
|
// they appear in f.
|
|
//
|
|
// For compatibility with Go 1.0, Symbols omits the null symbol at index 0.
|
|
// After retrieving the symbols as symtab, an externally supplied index x
|
|
// corresponds to symtab[x-1], not symtab[x].
|
|
func (f *File) Symbols() ([]Symbol, error) {
|
|
sym, _, err := f.getSymbols(SHT_SYMTAB)
|
|
return sym, err
|
|
}
|
|
|
|
// DynamicSymbols returns the dynamic symbol table for f. The symbols
|
|
// will be listed in the order they appear in f.
|
|
//
|
|
// For compatibility with Symbols, DynamicSymbols omits the null symbol at index 0.
|
|
// After retrieving the symbols as symtab, an externally supplied index x
|
|
// corresponds to symtab[x-1], not symtab[x].
|
|
func (f *File) DynamicSymbols() ([]Symbol, error) {
|
|
sym, _, err := f.getSymbols(SHT_DYNSYM)
|
|
return sym, err
|
|
}
|
|
|
|
type ImportedSymbol struct {
|
|
Name string
|
|
Version string
|
|
Library string
|
|
}
|
|
|
|
// ImportedSymbols returns the names of all symbols
|
|
// referred to by the binary f that are expected to be
|
|
// satisfied by other libraries at dynamic load time.
|
|
// It does not return weak symbols.
|
|
func (f *File) ImportedSymbols() ([]ImportedSymbol, error) {
|
|
sym, str, err := f.getSymbols(SHT_DYNSYM)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
f.gnuVersionInit(str)
|
|
var all []ImportedSymbol
|
|
for i, s := range sym {
|
|
if ST_BIND(s.Info) == STB_GLOBAL && s.Section == SHN_UNDEF {
|
|
all = append(all, ImportedSymbol{Name: s.Name})
|
|
f.gnuVersion(i, &all[len(all)-1])
|
|
}
|
|
}
|
|
return all, nil
|
|
}
|
|
|
|
type verneed struct {
|
|
File string
|
|
Name string
|
|
}
|
|
|
|
// gnuVersionInit parses the GNU version tables
|
|
// for use by calls to gnuVersion.
|
|
func (f *File) gnuVersionInit(str []byte) {
|
|
// Accumulate verneed information.
|
|
vn := f.SectionByType(SHT_GNU_VERNEED)
|
|
if vn == nil {
|
|
return
|
|
}
|
|
d, _ := vn.Data()
|
|
|
|
var need []verneed
|
|
i := 0
|
|
for {
|
|
if i+16 > len(d) {
|
|
break
|
|
}
|
|
vers := f.ByteOrder.Uint16(d[i : i+2])
|
|
if vers != 1 {
|
|
break
|
|
}
|
|
cnt := f.ByteOrder.Uint16(d[i+2 : i+4])
|
|
fileoff := f.ByteOrder.Uint32(d[i+4 : i+8])
|
|
aux := f.ByteOrder.Uint32(d[i+8 : i+12])
|
|
next := f.ByteOrder.Uint32(d[i+12 : i+16])
|
|
file, _ := getString(str, int(fileoff))
|
|
|
|
var name string
|
|
j := i + int(aux)
|
|
for c := 0; c < int(cnt); c++ {
|
|
if j+16 > len(d) {
|
|
break
|
|
}
|
|
// hash := f.ByteOrder.Uint32(d[j:j+4])
|
|
// flags := f.ByteOrder.Uint16(d[j+4:j+6])
|
|
other := f.ByteOrder.Uint16(d[j+6 : j+8])
|
|
nameoff := f.ByteOrder.Uint32(d[j+8 : j+12])
|
|
next := f.ByteOrder.Uint32(d[j+12 : j+16])
|
|
name, _ = getString(str, int(nameoff))
|
|
ndx := int(other)
|
|
if ndx >= len(need) {
|
|
a := make([]verneed, 2*(ndx+1))
|
|
copy(a, need)
|
|
need = a
|
|
}
|
|
|
|
need[ndx] = verneed{file, name}
|
|
if next == 0 {
|
|
break
|
|
}
|
|
j += int(next)
|
|
}
|
|
|
|
if next == 0 {
|
|
break
|
|
}
|
|
i += int(next)
|
|
}
|
|
|
|
// Versym parallels symbol table, indexing into verneed.
|
|
vs := f.SectionByType(SHT_GNU_VERSYM)
|
|
if vs == nil {
|
|
return
|
|
}
|
|
d, _ = vs.Data()
|
|
|
|
f.gnuNeed = need
|
|
f.gnuVersym = d
|
|
}
|
|
|
|
// gnuVersion adds Library and Version information to sym,
|
|
// which came from offset i of the symbol table.
|
|
func (f *File) gnuVersion(i int, sym *ImportedSymbol) {
|
|
// Each entry is two bytes.
|
|
i = (i + 1) * 2
|
|
if i >= len(f.gnuVersym) {
|
|
return
|
|
}
|
|
j := int(f.ByteOrder.Uint16(f.gnuVersym[i:]))
|
|
if j < 2 || j >= len(f.gnuNeed) {
|
|
return
|
|
}
|
|
n := &f.gnuNeed[j]
|
|
sym.Library = n.File
|
|
sym.Version = n.Name
|
|
}
|
|
|
|
// ImportedLibraries returns the names of all libraries
|
|
// referred to by the binary f that are expected to be
|
|
// linked with the binary at dynamic link time.
|
|
func (f *File) ImportedLibraries() ([]string, error) {
|
|
return f.DynString(DT_NEEDED)
|
|
}
|
|
|
|
// DynString returns the strings listed for the given tag in the file's dynamic
|
|
// section.
|
|
//
|
|
// The tag must be one that takes string values: DT_NEEDED, DT_SONAME, DT_RPATH, or
|
|
// DT_RUNPATH.
|
|
func (f *File) DynString(tag DynTag) ([]string, error) {
|
|
switch tag {
|
|
case DT_NEEDED, DT_SONAME, DT_RPATH, DT_RUNPATH:
|
|
default:
|
|
return nil, fmt.Errorf("non-string-valued tag %v", tag)
|
|
}
|
|
ds := f.SectionByType(SHT_DYNAMIC)
|
|
if ds == nil {
|
|
// not dynamic, so no libraries
|
|
return nil, nil
|
|
}
|
|
d, err := ds.Data()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
str, err := f.stringTable(ds.Link)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
var all []string
|
|
for len(d) > 0 {
|
|
var t DynTag
|
|
var v uint64
|
|
switch f.Class {
|
|
case ELFCLASS32:
|
|
t = DynTag(f.ByteOrder.Uint32(d[0:4]))
|
|
v = uint64(f.ByteOrder.Uint32(d[4:8]))
|
|
d = d[8:]
|
|
case ELFCLASS64:
|
|
t = DynTag(f.ByteOrder.Uint64(d[0:8]))
|
|
v = f.ByteOrder.Uint64(d[8:16])
|
|
d = d[16:]
|
|
}
|
|
if t == tag {
|
|
s, ok := getString(str, int(v))
|
|
if ok {
|
|
all = append(all, s)
|
|
}
|
|
}
|
|
}
|
|
return all, nil
|
|
}
|