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cmd/link: split PE loader into its own package
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For #22095

Change-Id: I8f48fce571b69a7e8edf2ad7733ffdfd38676e63
Reviewed-on: https://go-review.googlesource.com/70310
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
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@crawshaw
crawshaw committed Oct 12, 2017
1 parent fd9fac2 commit d06815b
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Showing 4 changed files with 82 additions and 47 deletions.
3 changes: 2 additions & 1 deletion src/cmd/dist/buildtool.go
View file
Expand Up @@ -67,8 +67,9 @@ var bootstrapDirs = []string{
"cmd/link/internal/arm",
"cmd/link/internal/arm64",
"cmd/link/internal/ld",
"cmd/link/internal/loadmacho",
"cmd/link/internal/loadelf",
"cmd/link/internal/loadmacho",
"cmd/link/internal/loadpe",
"cmd/link/internal/mips",
"cmd/link/internal/mips64",
"cmd/link/internal/objfile",
Expand Down
12 changes: 12 additions & 0 deletions src/cmd/link/internal/ld/lib.go
View file
Expand Up @@ -38,6 +38,7 @@ import (
"cmd/internal/sys"
"cmd/link/internal/loadelf"
"cmd/link/internal/loadmacho"
"cmd/link/internal/loadpe"
"cmd/link/internal/objfile"
"cmd/link/internal/sym"
"crypto/sha1"
Expand Down Expand Up @@ -1410,6 +1411,17 @@ func ldobj(ctxt *Link, f *bio.Reader, lib *sym.Library, length int64, pn string,
}

if c1 == 0x4c && c2 == 0x01 || c1 == 0x64 && c2 == 0x86 {
ldpe := func(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
textp, rsrc, err := loadpe.Load(ctxt.Arch, ctxt.Syms, f, pkg, length, pn)
if err != nil {
Errorf(nil, "%v", err)
return
}
if rsrc != nil {
setpersrc(ctxt, rsrc)
}
ctxt.Textp = append(ctxt.Textp, textp...)
}
return ldhostobj(ldpe, f, pkg, length, pn, file)
}

Expand Down
19 changes: 19 additions & 0 deletions src/cmd/link/internal/ld/pe.go
View file
Expand Up @@ -91,6 +91,25 @@ const (
IMAGE_SUBSYSTEM_WINDOWS_CUI = 3
)

// TODO(crawshaw): add these constants to debug/pe.
const (
IMAGE_SYM_TYPE_NULL = 0
IMAGE_SYM_TYPE_STRUCT = 8
IMAGE_SYM_DTYPE_FUNCTION = 0x20
IMAGE_SYM_DTYPE_ARRAY = 0x30
IMAGE_SYM_CLASS_EXTERNAL = 2
IMAGE_SYM_CLASS_STATIC = 3

IMAGE_REL_I386_DIR32 = 0x0006
IMAGE_REL_I386_SECREL = 0x000B
IMAGE_REL_I386_REL32 = 0x0014

IMAGE_REL_AMD64_ADDR64 = 0x0001
IMAGE_REL_AMD64_ADDR32 = 0x0002
IMAGE_REL_AMD64_REL32 = 0x0004
IMAGE_REL_AMD64_SECREL = 0x000B
)

// Copyright 2009 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.
Expand Down
95 changes: 49 additions & 46 deletions src/cmd/link/internal/ld/ldpe.go → src/cmd/link/internal/loadpe/ldpe.go
View file
Expand Up @@ -2,18 +2,19 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package ld
// 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"
"log"
"sort"
"strings"
)
Expand Down Expand Up @@ -102,6 +103,17 @@ const (
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.
Expand All @@ -119,19 +131,11 @@ func (f *peBiobuf) ReadAt(p []byte, off int64) (int, error) {
return n, nil
}

func ldpe(ctxt *Link, input *bio.Reader, pkg string, length int64, pn string) {
err := ldpeError(ctxt, input, pkg, length, pn)
if err != nil {
Errorf(nil, "%s: malformed pe file: %v", pn, err)
}
}

func ldpeError(ctxt *Link, input *bio.Reader, pkg string, length int64, pn string) error {
if ctxt.Debugvlog != 0 {
ctxt.Logf("%5.2f ldpe %s\n", Cputime(), pn)
}

localSymVersion := ctxt.Syms.IncVersion()
// 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)
Expand All @@ -145,7 +149,7 @@ func ldpeError(ctxt *Link, input *bio.Reader, pkg string, length int64, pn strin
// 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 err
return nil, nil, err
}
defer f.Close()

Expand All @@ -164,7 +168,7 @@ func ldpeError(ctxt *Link, input *bio.Reader, pkg string, length int64, pn strin
}

name := fmt.Sprintf("%s(%s)", pkg, sect.Name)
s := ctxt.Syms.Lookup(name, localSymVersion)
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
Expand All @@ -180,21 +184,21 @@ func ldpeError(ctxt *Link, input *bio.Reader, pkg string, length int64, pn strin
s.Type = sym.STEXT

default:
return fmt.Errorf("unexpected flags %#06x for PE section %s", sect.Characteristics, sect.Name)
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 err
return nil, nil, err
}
sectdata[sect] = data
s.P = data
}
s.Size = int64(sect.Size)
sectsyms[sect] = s
if sect.Name == ".rsrc" {
setpersrc(ctxt, s)
rsrc = s
}
}

Expand All @@ -219,49 +223,48 @@ func ldpeError(ctxt *Link, input *bio.Reader, pkg string, length int64, pn strin
for j, r := range rsect.Relocs {
rp := &rs[j]
if int(r.SymbolTableIndex) >= len(f.COFFSymbols) {
return fmt.Errorf("relocation number %d symbol index idx=%d cannot be large then number of symbols %d", j, 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(ctxt, f, pesym, sectsyms, localSymVersion)
gosym, err := readpesym(arch, syms, f, pesym, sectsyms, localSymVersion)
if err != nil {
return err
return nil, nil, err
}
if gosym == nil {
name, err := pesym.FullName(f.StringTable)
if err != nil {
name = string(pesym.Name[:])
}
return fmt.Errorf("reloc of invalid sym %s idx=%d type=%d", name, r.SymbolTableIndex, pesym.Type)
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:
Errorf(sectsyms[rsect], "%s: unknown relocation type %d;", pn, r.Type)
fallthrough
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(Le32(sectdata[rsect][rp.Off:])))
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(Le32(sectdata[rsect][rp.Off:])))
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(Le64(sectdata[rsect][rp.Off:]))
rp.Add = int64(binary.LittleEndian.Uint64(sectdata[rsect][rp.Off:]))
}

// ld -r could generate multiple section symbols for the
Expand All @@ -287,7 +290,7 @@ func ldpeError(ctxt *Link, input *bio.Reader, pkg string, length int64, pn strin

name, err := pesym.FullName(f.StringTable)
if err != nil {
return err
return nil, nil, err
}
if name == "" {
continue
Expand All @@ -309,9 +312,9 @@ func ldpeError(ctxt *Link, input *bio.Reader, pkg string, length int64, pn strin
}
}

s, err := readpesym(ctxt, f, pesym, sectsyms, localSymVersion)
s, err := readpesym(arch, syms, f, pesym, sectsyms, localSymVersion)
if err != nil {
return err
return nil, nil, err
}

if pesym.SectionNumber == 0 { // extern
Expand All @@ -327,21 +330,21 @@ func ldpeError(ctxt *Link, input *bio.Reader, pkg string, length int64, pn strin
} else if pesym.SectionNumber > 0 && int(pesym.SectionNumber) <= len(f.Sections) {
sect = f.Sections[pesym.SectionNumber-1]
if _, found := sectsyms[sect]; !found {
Errorf(s, "%s: missing sect.sym", pn)
return nil, nil, fmt.Errorf("%s: %v: missing sect.sym", pn, s)
}
} else {
Errorf(s, "%s: sectnum < 0!", pn)
return nil, nil, fmt.Errorf("%s: %v: sectnum < 0!", pn, s)
}

if sect == nil {
return nil
return nil, rsrc, nil
}

if s.Outer != nil {
if s.Attr.DuplicateOK() {
continue
}
Exitf("%s: duplicate symbol reference: %s in both %s and %s", pn, s.Name, s.Outer.Name, sectsyms[sect].Name)
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]
Expand All @@ -353,7 +356,7 @@ func ldpeError(ctxt *Link, input *bio.Reader, pkg string, length int64, pn strin
s.Outer = sectsym
if sectsym.Type == sym.STEXT {
if s.Attr.External() && !s.Attr.DuplicateOK() {
Errorf(s, "%s: duplicate symbol definition", pn)
return nil, nil, fmt.Errorf("%s: duplicate symbol definition", s.Name)
}
s.Attr |= sym.AttrExternal
}
Expand All @@ -371,28 +374,28 @@ func ldpeError(ctxt *Link, input *bio.Reader, pkg string, length int64, pn strin
}
if s.Type == sym.STEXT {
if s.Attr.OnList() {
log.Fatalf("symbol %s listed multiple times", s.Name)
return nil, nil, fmt.Errorf("symbol %s listed multiple times", s.Name)
}
s.Attr |= sym.AttrOnList
ctxt.Textp = append(ctxt.Textp, s)
textp = append(textp, s)
for s = s.Sub; s != nil; s = s.Sub {
if s.Attr.OnList() {
log.Fatalf("symbol %s listed multiple times", s.Name)
return nil, nil, fmt.Errorf("symbol %s listed multiple times", s.Name)
}
s.Attr |= sym.AttrOnList
ctxt.Textp = append(ctxt.Textp, s)
textp = append(textp, s)
}
}
}

return nil
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(ctxt *Link, f *pe.File, pesym *pe.COFFSymbol, sectsyms map[*pe.Section]*sym.Symbol, localSymVersion int) (*sym.Symbol, error) {
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
Expand All @@ -405,7 +408,7 @@ func readpesym(ctxt *Link, f *pe.File, pesym *pe.COFFSymbol, sectsyms map[*pe.Se
if strings.HasPrefix(name, "__imp_") {
name = name[6:] // __imp_Name => Name
}
if ctxt.Arch.Family == sys.I386 && name[0] == '_' {
if arch.Family == sys.I386 && name[0] == '_' {
name = name[1:] // _Name => Name
}
}
Expand All @@ -423,10 +426,10 @@ func readpesym(ctxt *Link, f *pe.File, pesym *pe.COFFSymbol, sectsyms map[*pe.Se
case IMAGE_SYM_DTYPE_FUNCTION, IMAGE_SYM_DTYPE_NULL:
switch pesym.StorageClass {
case IMAGE_SYM_CLASS_EXTERNAL: //global
s = ctxt.Syms.Lookup(name, 0)
s = syms.Lookup(name, 0)

case IMAGE_SYM_CLASS_NULL, IMAGE_SYM_CLASS_STATIC, IMAGE_SYM_CLASS_LABEL:
s = ctxt.Syms.Lookup(name, localSymVersion)
s = syms.Lookup(name, localSymVersion)
s.Attr |= sym.AttrDuplicateOK

default:
Expand Down

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