// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package loadpe implements a PE/COFF file reader.
package loadpe
import (
"cmd/internal/bio"
"cmd/internal/objabi"
"cmd/internal/sys"
"cmd/link/internal/sym"
"debug/pe"
"encoding/binary"
"errors"
"fmt"
"io"
"sort"
"strings"
)
const (
// TODO: the Microsoft doco says IMAGE_SYM_DTYPE_ARRAY is 3 (same with IMAGE_SYM_DTYPE_POINTER and IMAGE_SYM_DTYPE_FUNCTION)
IMAGE_SYM_UNDEFINED = 0
IMAGE_SYM_ABSOLUTE = -1
IMAGE_SYM_DEBUG = -2
IMAGE_SYM_TYPE_NULL = 0
IMAGE_SYM_TYPE_VOID = 1
IMAGE_SYM_TYPE_CHAR = 2
IMAGE_SYM_TYPE_SHORT = 3
IMAGE_SYM_TYPE_INT = 4
IMAGE_SYM_TYPE_LONG = 5
IMAGE_SYM_TYPE_FLOAT = 6
IMAGE_SYM_TYPE_DOUBLE = 7
IMAGE_SYM_TYPE_STRUCT = 8
IMAGE_SYM_TYPE_UNION = 9
IMAGE_SYM_TYPE_ENUM = 10
IMAGE_SYM_TYPE_MOE = 11
IMAGE_SYM_TYPE_BYTE = 12
IMAGE_SYM_TYPE_WORD = 13
IMAGE_SYM_TYPE_UINT = 14
IMAGE_SYM_TYPE_DWORD = 15
IMAGE_SYM_TYPE_PCODE = 32768
IMAGE_SYM_DTYPE_NULL = 0
IMAGE_SYM_DTYPE_POINTER = 0x10
IMAGE_SYM_DTYPE_FUNCTION = 0x20
IMAGE_SYM_DTYPE_ARRAY = 0x30
IMAGE_SYM_CLASS_END_OF_FUNCTION = -1
IMAGE_SYM_CLASS_NULL = 0
IMAGE_SYM_CLASS_AUTOMATIC = 1
IMAGE_SYM_CLASS_EXTERNAL = 2
IMAGE_SYM_CLASS_STATIC = 3
IMAGE_SYM_CLASS_REGISTER = 4
IMAGE_SYM_CLASS_EXTERNAL_DEF = 5
IMAGE_SYM_CLASS_LABEL = 6
IMAGE_SYM_CLASS_UNDEFINED_LABEL = 7
IMAGE_SYM_CLASS_MEMBER_OF_STRUCT = 8
IMAGE_SYM_CLASS_ARGUMENT = 9
IMAGE_SYM_CLASS_STRUCT_TAG = 10
IMAGE_SYM_CLASS_MEMBER_OF_UNION = 11
IMAGE_SYM_CLASS_UNION_TAG = 12
IMAGE_SYM_CLASS_TYPE_DEFINITION = 13
IMAGE_SYM_CLASS_UNDEFINED_STATIC = 14
IMAGE_SYM_CLASS_ENUM_TAG = 15
IMAGE_SYM_CLASS_MEMBER_OF_ENUM = 16
IMAGE_SYM_CLASS_REGISTER_PARAM = 17
IMAGE_SYM_CLASS_BIT_FIELD = 18
IMAGE_SYM_CLASS_FAR_EXTERNAL = 68 /* Not in PECOFF v8 spec */
IMAGE_SYM_CLASS_BLOCK = 100
IMAGE_SYM_CLASS_FUNCTION = 101
IMAGE_SYM_CLASS_END_OF_STRUCT = 102
IMAGE_SYM_CLASS_FILE = 103
IMAGE_SYM_CLASS_SECTION = 104
IMAGE_SYM_CLASS_WEAK_EXTERNAL = 105
IMAGE_SYM_CLASS_CLR_TOKEN = 107
IMAGE_REL_I386_ABSOLUTE = 0x0000
IMAGE_REL_I386_DIR16 = 0x0001
IMAGE_REL_I386_REL16 = 0x0002
IMAGE_REL_I386_DIR32 = 0x0006
IMAGE_REL_I386_DIR32NB = 0x0007
IMAGE_REL_I386_SEG12 = 0x0009
IMAGE_REL_I386_SECTION = 0x000A
IMAGE_REL_I386_SECREL = 0x000B
IMAGE_REL_I386_TOKEN = 0x000C
IMAGE_REL_I386_SECREL7 = 0x000D
IMAGE_REL_I386_REL32 = 0x0014
IMAGE_REL_AMD64_ABSOLUTE = 0x0000
IMAGE_REL_AMD64_ADDR64 = 0x0001
IMAGE_REL_AMD64_ADDR32 = 0x0002
IMAGE_REL_AMD64_ADDR32NB = 0x0003
IMAGE_REL_AMD64_REL32 = 0x0004
IMAGE_REL_AMD64_REL32_1 = 0x0005
IMAGE_REL_AMD64_REL32_2 = 0x0006
IMAGE_REL_AMD64_REL32_3 = 0x0007
IMAGE_REL_AMD64_REL32_4 = 0x0008
IMAGE_REL_AMD64_REL32_5 = 0x0009
IMAGE_REL_AMD64_SECTION = 0x000A
IMAGE_REL_AMD64_SECREL = 0x000B
IMAGE_REL_AMD64_SECREL7 = 0x000C
IMAGE_REL_AMD64_TOKEN = 0x000D
IMAGE_REL_AMD64_SREL32 = 0x000E
IMAGE_REL_AMD64_PAIR = 0x000F
IMAGE_REL_AMD64_SSPAN32 = 0x0010
)
// TODO(crawshaw): de-duplicate these symbols with cmd/internal/ld, ideally in debug/pe.
const (
IMAGE_SCN_CNT_CODE = 0x00000020
IMAGE_SCN_CNT_INITIALIZED_DATA = 0x00000040
IMAGE_SCN_CNT_UNINITIALIZED_DATA = 0x00000080
IMAGE_SCN_MEM_DISCARDABLE = 0x02000000
IMAGE_SCN_MEM_EXECUTE = 0x20000000
IMAGE_SCN_MEM_READ = 0x40000000
IMAGE_SCN_MEM_WRITE = 0x80000000
)
// TODO(brainman): maybe just add ReadAt method to bio.Reader instead of creating peBiobuf
// peBiobuf makes bio.Reader look like io.ReaderAt.
type peBiobuf bio.Reader
func (f *peBiobuf) ReadAt(p []byte, off int64) (int, error) {
ret := ((*bio.Reader)(f)).Seek(off, 0)
if ret < 0 {
return 0, errors.New("fail to seek")
}
n, err := f.Read(p)
if err != nil {
return 0, err
}
return n, nil
}
// Load loads the PE file pn from input.
// Symbols are written into syms, and a slice of the text symbols is returned.
// If an .rsrc section is found, its symbol is returned as rsrc.
func Load(arch *sys.Arch, syms *sym.Symbols, input *bio.Reader, pkg string, length int64, pn string) (textp []*sym.Symbol, rsrc *sym.Symbol, err error) {
localSymVersion := syms.IncVersion()
sectsyms := make(map[*pe.Section]*sym.Symbol)
sectdata := make(map[*pe.Section][]byte)
// Some input files are archives containing multiple of
// object files, and pe.NewFile seeks to the start of
// input file and get confused. Create section reader
// to stop pe.NewFile looking before current position.
sr := io.NewSectionReader((*peBiobuf)(input), input.Offset(), 1<<63-1)
// TODO: replace pe.NewFile with pe.Load (grep for "add Load function" in debug/pe for details)
f, err := pe.NewFile(sr)
if err != nil {
return nil, nil, err
}
defer f.Close()
// TODO return error if found .cormeta
// create symbols for mapped sections
for _, sect := range f.Sections {
if sect.Characteristics&IMAGE_SCN_MEM_DISCARDABLE != 0 {
continue
}
if sect.Characteristics&(IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 {
// This has been seen for .idata sections, which we
// want to ignore. See issues 5106 and 5273.
continue
}
name := fmt.Sprintf("%s(%s)", pkg, sect.Name)
s := syms.Lookup(name, localSymVersion)
switch sect.Characteristics & (IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE) {
case IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ: //.rdata
s.Type = sym.SRODATA
case IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE: //.bss
s.Type = sym.SNOPTRBSS
case IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE: //.data
s.Type = sym.SNOPTRDATA
case IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_READ: //.text
s.Type = sym.STEXT
default:
return nil, nil, fmt.Errorf("unexpected flags %#06x for PE section %s", sect.Characteristics, sect.Name)
}
if s.Type != sym.SNOPTRBSS {
data, err := sect.Data()
if err != nil {
return nil, nil, err
}
sectdata[sect] = data
s.P = data
}
s.Size = int64(sect.Size)
sectsyms[sect] = s
if sect.Name == ".rsrc" {
rsrc = s
}
}
// load relocations
for _, rsect := range f.Sections {
if _, found := sectsyms[rsect]; !found {
continue
}
if rsect.NumberOfRelocations == 0 {
continue
}
if rsect.Characteristics&IMAGE_SCN_MEM_DISCARDABLE != 0 {
continue
}
if rsect.Characteristics&(IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 {
// This has been seen for .idata sections, which we
// want to ignore. See issues 5106 and 5273.
continue
}
rs := make([]sym.Reloc, rsect.NumberOfRelocations)
for j, r := range rsect.Relocs {
rp := &rs[j]
if int(r.SymbolTableIndex) >= len(f.COFFSymbols) {
return nil, nil, fmt.Errorf("relocation number %d symbol index idx=%d cannot be large then number of symbols %d", j, r.SymbolTableIndex, len(f.COFFSymbols))
}
pesym := &f.COFFSymbols[r.SymbolTableIndex]
gosym, err := readpesym(arch, syms, f, pesym, sectsyms, localSymVersion)
if err != nil {
return nil, nil, err
}
if gosym == nil {
name, err := pesym.FullName(f.StringTable)
if err != nil {
name = string(pesym.Name[:])
}
return nil, nil, fmt.Errorf("reloc of invalid sym %s idx=%d type=%d", name, r.SymbolTableIndex, pesym.Type)
}
rp.Sym = gosym
rp.Siz = 4
rp.Off = int32(r.VirtualAddress)
switch r.Type {
default:
return nil, nil, fmt.Errorf("%s: %v: unknown relocation type %v", pn, sectsyms[rsect], r.Type)
case IMAGE_REL_I386_REL32, IMAGE_REL_AMD64_REL32,
IMAGE_REL_AMD64_ADDR32, // R_X86_64_PC32
IMAGE_REL_AMD64_ADDR32NB:
rp.Type = objabi.R_PCREL
rp.Add = int64(int32(binary.LittleEndian.Uint32(sectdata[rsect][rp.Off:])))
case IMAGE_REL_I386_DIR32NB, IMAGE_REL_I386_DIR32:
rp.Type = objabi.R_ADDR
// load addend from image
rp.Add = int64(int32(binary.LittleEndian.Uint32(sectdata[rsect][rp.Off:])))
case IMAGE_REL_AMD64_ADDR64: // R_X86_64_64
rp.Siz = 8
rp.Type = objabi.R_ADDR
// load addend from image
rp.Add = int64(binary.LittleEndian.Uint64(sectdata[rsect][rp.Off:]))
}
// ld -r could generate multiple section symbols for the
// same section but with different values, we have to take
// that into account
if issect(pesym) {
rp.Add += int64(pesym.Value)
}
}
sort.Sort(sym.RelocByOff(rs[:rsect.NumberOfRelocations]))
s := sectsyms[rsect]
s.R = rs
s.R = s.R[:rsect.NumberOfRelocations]
}
// enter sub-symbols into symbol table.
for i, numaux := 0, 0; i < len(f.COFFSymbols); i += numaux + 1 {
pesym := &f.COFFSymbols[i]
numaux = int(pesym.NumberOfAuxSymbols)
name, err := pesym.FullName(f.StringTable)
if err != nil {
return nil, nil, err
}
if name == "" {
continue
}
if issect(pesym) {
continue
}
if int(pesym.SectionNumber) > len(f.Sections) {
continue
}
if pesym.SectionNumber == IMAGE_SYM_DEBUG {
continue
}
var sect *pe.Section
if pesym.SectionNumber > 0 {
sect = f.Sections[pesym.SectionNumber-1]
if _, found := sectsyms[sect]; !found {
continue
}
}
s, err := readpesym(arch, syms, f, pesym, sectsyms, localSymVersion)
if err != nil {
return nil, nil, err
}
if pesym.SectionNumber == 0 { // extern
if s.Type == sym.SDYNIMPORT {
s.Plt = -2 // flag for dynimport in PE object files.
}
if s.Type == sym.SXREF && pesym.Value > 0 { // global data
s.Type = sym.SNOPTRDATA
s.Size = int64(pesym.Value)
}
continue
} else if pesym.SectionNumber > 0 && int(pesym.SectionNumber) <= len(f.Sections) {
sect = f.Sections[pesym.SectionNumber-1]
if _, found := sectsyms[sect]; !found {
return nil, nil, fmt.Errorf("%s: %v: missing sect.sym", pn, s)
}
} else {
return nil, nil, fmt.Errorf("%s: %v: sectnum < 0!", pn, s)
}
if sect == nil {
return nil, rsrc, nil
}
if s.Outer != nil {
if s.Attr.DuplicateOK() {
continue
}
return nil, nil, fmt.Errorf("%s: duplicate symbol reference: %s in both %s and %s", pn, s.Name, s.Outer.Name, sectsyms[sect].Name)
}
sectsym := sectsyms[sect]
s.Sub = sectsym.Sub
sectsym.Sub = s
s.Type = sectsym.Type
s.Attr |= sym.AttrSubSymbol
s.Value = int64(pesym.Value)
s.Size = 4
s.Outer = sectsym
if sectsym.Type == sym.STEXT {
if s.Attr.External() && !s.Attr.DuplicateOK() {
return nil, nil, fmt.Errorf("%s: duplicate symbol definition", s.Name)
}
s.Attr |= sym.AttrExternal
}
}
// Sort outer lists by address, adding to textp.
// This keeps textp in increasing address order.
for _, sect := range f.Sections {
s := sectsyms[sect]
if s == nil {
continue
}
if s.Sub != nil {
s.Sub = sym.SortSub(s.Sub)
}
if s.Type == sym.STEXT {
if s.Attr.OnList() {
return nil, nil, fmt.Errorf("symbol %s listed multiple times", s.Name)
}
s.Attr |= sym.AttrOnList
textp = append(textp, s)
for s = s.Sub; s != nil; s = s.Sub {
if s.Attr.OnList() {
return nil, nil, fmt.Errorf("symbol %s listed multiple times", s.Name)
}
s.Attr |= sym.AttrOnList
textp = append(textp, s)
}
}
}
return textp, rsrc, nil
}
func issect(s *pe.COFFSymbol) bool {
return s.StorageClass == IMAGE_SYM_CLASS_STATIC && s.Type == 0 && s.Name[0] == '.'
}
func readpesym(arch *sys.Arch, syms *sym.Symbols, f *pe.File, pesym *pe.COFFSymbol, sectsyms map[*pe.Section]*sym.Symbol, localSymVersion int) (*sym.Symbol, error) {
symname, err := pesym.FullName(f.StringTable)
if err != nil {
return nil, err
}
var name string
if issect(pesym) {
name = sectsyms[f.Sections[pesym.SectionNumber-1]].Name
} else {
name = symname
if strings.HasPrefix(name, "__imp_") {
name = name[6:] // __imp_Name => Name
}
if arch.Family == sys.I386 && name[0] == '_' {
name = name[1:] // _Name => Name
}
}
// remove last @XXX
if i := strings.LastIndex(name, "@"); i >= 0 {
name = name[:i]
}
var s *sym.Symbol
switch pesym.Type {
default:
return nil, fmt.Errorf("%s: invalid symbol type %d", symname, pesym.Type)
case IMAGE_SYM_DTYPE_FUNCTION, IMAGE_SYM_DTYPE_NULL:
switch pesym.StorageClass {
case IMAGE_SYM_CLASS_EXTERNAL: //global
s = syms.Lookup(name, 0)
case IMAGE_SYM_CLASS_NULL, IMAGE_SYM_CLASS_STATIC, IMAGE_SYM_CLASS_LABEL:
s = syms.Lookup(name, localSymVersion)
s.Attr |= sym.AttrDuplicateOK
default:
return nil, fmt.Errorf("%s: invalid symbol binding %d", symname, pesym.StorageClass)
}
}
if s != nil && s.Type == 0 && (pesym.StorageClass != IMAGE_SYM_CLASS_STATIC || pesym.Value != 0) {
s.Type = sym.SXREF
}
if strings.HasPrefix(symname, "__imp_") {
s.Got = -2 // flag for __imp_
}
return s, nil
}