Current File : //usr/local/go119/src/cmd/link/internal/loadpe/ldpe.go
// 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 (
"bytes"
"cmd/internal/bio"
"cmd/internal/objabi"
"cmd/internal/sys"
"cmd/link/internal/loader"
"cmd/link/internal/sym"
"debug/pe"
"encoding/binary"
"errors"
"fmt"
"io"
"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
IMAGE_REL_ARM_ABSOLUTE = 0x0000
IMAGE_REL_ARM_ADDR32 = 0x0001
IMAGE_REL_ARM_ADDR32NB = 0x0002
IMAGE_REL_ARM_BRANCH24 = 0x0003
IMAGE_REL_ARM_BRANCH11 = 0x0004
IMAGE_REL_ARM_SECTION = 0x000E
IMAGE_REL_ARM_SECREL = 0x000F
IMAGE_REL_ARM_MOV32 = 0x0010
IMAGE_REL_THUMB_MOV32 = 0x0011
IMAGE_REL_THUMB_BRANCH20 = 0x0012
IMAGE_REL_THUMB_BRANCH24 = 0x0014
IMAGE_REL_THUMB_BLX23 = 0x0015
IMAGE_REL_ARM_PAIR = 0x0016
IMAGE_REL_ARM64_ABSOLUTE = 0x0000
IMAGE_REL_ARM64_ADDR32 = 0x0001
IMAGE_REL_ARM64_ADDR32NB = 0x0002
IMAGE_REL_ARM64_BRANCH26 = 0x0003
IMAGE_REL_ARM64_PAGEBASE_REL21 = 0x0004
IMAGE_REL_ARM64_REL21 = 0x0005
IMAGE_REL_ARM64_PAGEOFFSET_12A = 0x0006
IMAGE_REL_ARM64_PAGEOFFSET_12L = 0x0007
IMAGE_REL_ARM64_SECREL = 0x0008
IMAGE_REL_ARM64_SECREL_LOW12A = 0x0009
IMAGE_REL_ARM64_SECREL_HIGH12A = 0x000A
IMAGE_REL_ARM64_SECREL_LOW12L = 0x000B
IMAGE_REL_ARM64_TOKEN = 0x000C
IMAGE_REL_ARM64_SECTION = 0x000D
IMAGE_REL_ARM64_ADDR64 = 0x000E
IMAGE_REL_ARM64_BRANCH19 = 0x000F
IMAGE_REL_ARM64_BRANCH14 = 0x0010
IMAGE_REL_ARM64_REL32 = 0x0011
)
// 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)).MustSeek(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
}
// makeUpdater creates a loader.SymbolBuilder if one hasn't been created previously.
// We use this to lazily make SymbolBuilders as we don't always need a builder, and creating them for all symbols might be an error.
func makeUpdater(l *loader.Loader, bld *loader.SymbolBuilder, s loader.Sym) *loader.SymbolBuilder {
if bld != nil {
return bld
}
bld = l.MakeSymbolUpdater(s)
return bld
}
// peLoaderState holds various bits of useful state information needed
// while loading a PE object file.
type peLoaderState struct {
l *loader.Loader
arch *sys.Arch
f *pe.File
pn string
sectsyms map[*pe.Section]loader.Sym
defWithImp map[string]struct{}
comdats map[uint16]int64 // key is section index, val is size
sectdata map[*pe.Section][]byte
localSymVersion int
}
// comdatDefinitions records the names of symbols for which we've
// previously seen a definition in COMDAT. Key is symbol name, value
// is symbol size (or -1 if we're using the "any" strategy).
var comdatDefinitions = make(map[string]int64)
// 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 or set of .rsrc$xx sections is found, its symbols are
// returned as rsrc.
func Load(l *loader.Loader, arch *sys.Arch, localSymVersion int, input *bio.Reader, pkg string, length int64, pn string) (textp []loader.Sym, rsrc []loader.Sym, err error) {
state := &peLoaderState{
l: l,
arch: arch,
sectsyms: make(map[*pe.Section]loader.Sym),
sectdata: make(map[*pe.Section][]byte),
localSymVersion: localSymVersion,
pn: pn,
}
// 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()
state.f = f
// TODO return error if found .cormeta
// create symbols for mapped sections
for _, sect := range f.Sections {
if sect.Characteristics&pe.IMAGE_SCN_MEM_DISCARDABLE != 0 {
continue
}
if sect.Characteristics&(pe.IMAGE_SCN_CNT_CODE|pe.IMAGE_SCN_CNT_INITIALIZED_DATA|pe.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 := state.l.LookupOrCreateCgoExport(name, localSymVersion)
bld := l.MakeSymbolUpdater(s)
switch sect.Characteristics & (pe.IMAGE_SCN_CNT_UNINITIALIZED_DATA | pe.IMAGE_SCN_CNT_INITIALIZED_DATA | pe.IMAGE_SCN_MEM_READ | pe.IMAGE_SCN_MEM_WRITE | pe.IMAGE_SCN_CNT_CODE | pe.IMAGE_SCN_MEM_EXECUTE) {
case pe.IMAGE_SCN_CNT_INITIALIZED_DATA | pe.IMAGE_SCN_MEM_READ: //.rdata
bld.SetType(sym.SRODATA)
case pe.IMAGE_SCN_CNT_UNINITIALIZED_DATA | pe.IMAGE_SCN_MEM_READ | pe.IMAGE_SCN_MEM_WRITE: //.bss
bld.SetType(sym.SNOPTRBSS)
case pe.IMAGE_SCN_CNT_INITIALIZED_DATA | pe.IMAGE_SCN_MEM_READ | pe.IMAGE_SCN_MEM_WRITE: //.data
bld.SetType(sym.SNOPTRDATA)
case pe.IMAGE_SCN_CNT_CODE | pe.IMAGE_SCN_MEM_EXECUTE | pe.IMAGE_SCN_MEM_READ: //.text
bld.SetType(sym.STEXT)
default:
return nil, nil, fmt.Errorf("unexpected flags %#06x for PE section %s", sect.Characteristics, sect.Name)
}
if bld.Type() != sym.SNOPTRBSS {
data, err := sect.Data()
if err != nil {
return nil, nil, err
}
state.sectdata[sect] = data
bld.SetData(data)
}
bld.SetSize(int64(sect.Size))
state.sectsyms[sect] = s
if sect.Name == ".rsrc" || strings.HasPrefix(sect.Name, ".rsrc$") {
rsrc = append(rsrc, s)
}
}
// Make a prepass over the symbols to detect situations where
// we have both a defined symbol X and an import symbol __imp_X
// (needed by readpesym()).
if err := state.preprocessSymbols(); err != nil {
return nil, nil, err
}
// load relocations
for _, rsect := range f.Sections {
if _, found := state.sectsyms[rsect]; !found {
continue
}
if rsect.NumberOfRelocations == 0 {
continue
}
if rsect.Characteristics&pe.IMAGE_SCN_MEM_DISCARDABLE != 0 {
continue
}
if rsect.Characteristics&(pe.IMAGE_SCN_CNT_CODE|pe.IMAGE_SCN_CNT_INITIALIZED_DATA|pe.IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 {
// This has been seen for .idata sections, which we
// want to ignore. See issues 5106 and 5273.
continue
}
splitResources := strings.HasPrefix(rsect.Name, ".rsrc$")
sb := l.MakeSymbolUpdater(state.sectsyms[rsect])
for j, r := range rsect.Relocs {
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 := state.readpesym(pesym)
if err != nil {
return nil, nil, err
}
if gosym == 0 {
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)
}
rSym := gosym
rSize := uint8(4)
rOff := int32(r.VirtualAddress)
var rAdd int64
var rType objabi.RelocType
switch arch.Family {
default:
return nil, nil, fmt.Errorf("%s: unsupported arch %v", pn, arch.Family)
case sys.I386, sys.AMD64:
switch r.Type {
default:
return nil, nil, fmt.Errorf("%s: %v: unknown relocation type %v", pn, state.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:
rType = objabi.R_PCREL
rAdd = int64(int32(binary.LittleEndian.Uint32(state.sectdata[rsect][rOff:])))
case IMAGE_REL_I386_DIR32NB, IMAGE_REL_I386_DIR32:
rType = objabi.R_ADDR
// load addend from image
rAdd = int64(int32(binary.LittleEndian.Uint32(state.sectdata[rsect][rOff:])))
case IMAGE_REL_AMD64_ADDR64: // R_X86_64_64
rSize = 8
rType = objabi.R_ADDR
// load addend from image
rAdd = int64(binary.LittleEndian.Uint64(state.sectdata[rsect][rOff:]))
}
case sys.ARM:
switch r.Type {
default:
return nil, nil, fmt.Errorf("%s: %v: unknown ARM relocation type %v", pn, state.sectsyms[rsect], r.Type)
case IMAGE_REL_ARM_SECREL:
rType = objabi.R_PCREL
rAdd = int64(int32(binary.LittleEndian.Uint32(state.sectdata[rsect][rOff:])))
case IMAGE_REL_ARM_ADDR32, IMAGE_REL_ARM_ADDR32NB:
rType = objabi.R_ADDR
rAdd = int64(int32(binary.LittleEndian.Uint32(state.sectdata[rsect][rOff:])))
case IMAGE_REL_ARM_BRANCH24:
rType = objabi.R_CALLARM
rAdd = int64(int32(binary.LittleEndian.Uint32(state.sectdata[rsect][rOff:])))
}
case sys.ARM64:
switch r.Type {
default:
return nil, nil, fmt.Errorf("%s: %v: unknown ARM64 relocation type %v", pn, state.sectsyms[rsect], r.Type)
case IMAGE_REL_ARM64_ADDR32, IMAGE_REL_ARM64_ADDR32NB:
rType = objabi.R_ADDR
rAdd = int64(int32(binary.LittleEndian.Uint32(state.sectdata[rsect][rOff:])))
}
}
// ld -r could generate multiple section symbols for the
// same section but with different values, we have to take
// that into account, or in the case of split resources,
// the section and its symbols are split into two sections.
if issect(pesym) || splitResources {
rAdd += int64(pesym.Value)
}
rel, _ := sb.AddRel(rType)
rel.SetOff(rOff)
rel.SetSiz(rSize)
rel.SetSym(rSym)
rel.SetAdd(rAdd)
}
sb.SortRelocs()
}
// 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
}
if pesym.SectionNumber == IMAGE_SYM_ABSOLUTE && bytes.Equal(pesym.Name[:], []byte("@feat.00")) {
// Microsoft's linker looks at whether all input objects have an empty
// section called @feat.00. If all of them do, then it enables SEH;
// otherwise it doesn't enable that feature. So, since around the Windows
// XP SP2 era, most tools that make PE objects just tack on that section,
// so that it won't gimp Microsoft's linker logic. Go doesn't support SEH,
// so in theory, none of this really matters to us. But actually, if the
// linker tries to ingest an object with @feat.00 -- which are produced by
// LLVM's resource compiler, for example -- it chokes because of the
// IMAGE_SYM_ABSOLUTE section that it doesn't know how to deal with. Since
// @feat.00 is just a marking anyway, skip IMAGE_SYM_ABSOLUTE sections that
// are called @feat.00.
continue
}
var sect *pe.Section
if pesym.SectionNumber > 0 {
sect = f.Sections[pesym.SectionNumber-1]
if _, found := state.sectsyms[sect]; !found {
continue
}
}
bld, s, err := state.readpesym(pesym)
if err != nil {
return nil, nil, err
}
if pesym.SectionNumber == 0 { // extern
if l.SymType(s) == sym.SDYNIMPORT {
bld = makeUpdater(l, bld, s)
bld.SetPlt(-2) // flag for dynimport in PE object files.
}
if l.SymType(s) == sym.SXREF && pesym.Value > 0 { // global data
bld = makeUpdater(l, bld, s)
bld.SetType(sym.SNOPTRDATA)
bld.SetSize(int64(pesym.Value))
}
continue
} else if pesym.SectionNumber > 0 && int(pesym.SectionNumber) <= len(f.Sections) {
sect = f.Sections[pesym.SectionNumber-1]
if _, found := state.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, nil, nil
}
// Check for COMDAT symbol.
if sz, ok1 := state.comdats[uint16(pesym.SectionNumber-1)]; ok1 {
if psz, ok2 := comdatDefinitions[l.SymName(s)]; ok2 {
if sz == psz {
// OK to discard, we've seen an instance
// already.
continue
}
}
}
if l.OuterSym(s) != 0 {
if l.AttrDuplicateOK(s) {
continue
}
outerName := l.SymName(l.OuterSym(s))
sectName := l.SymName(state.sectsyms[sect])
return nil, nil, fmt.Errorf("%s: duplicate symbol reference: %s in both %s and %s", pn, l.SymName(s), outerName, sectName)
}
bld = makeUpdater(l, bld, s)
sectsym := state.sectsyms[sect]
bld.SetType(l.SymType(sectsym))
l.AddInteriorSym(sectsym, s)
bld.SetValue(int64(pesym.Value))
bld.SetSize(4)
if l.SymType(sectsym) == sym.STEXT {
if bld.External() && !bld.DuplicateOK() {
return nil, nil, fmt.Errorf("%s: duplicate symbol definition", l.SymName(s))
}
bld.SetExternal(true)
}
if sz, ok := state.comdats[uint16(pesym.SectionNumber-1)]; ok {
// This is a COMDAT definition. Record that we're picking
// this instance so that we can ignore future defs.
if _, ok := comdatDefinitions[l.SymName(s)]; ok {
return nil, nil, fmt.Errorf("internal error: preexisting COMDAT definition for %q", name)
}
comdatDefinitions[l.SymName(s)] = sz
}
}
// Sort outer lists by address, adding to textp.
// This keeps textp in increasing address order.
for _, sect := range f.Sections {
s := state.sectsyms[sect]
if s == 0 {
continue
}
l.SortSub(s)
if l.SymType(s) == sym.STEXT {
for ; s != 0; s = l.SubSym(s) {
if l.AttrOnList(s) {
return nil, nil, fmt.Errorf("symbol %s listed multiple times", l.SymName(s))
}
l.SetAttrOnList(s, true)
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 (state *peLoaderState) readpesym(pesym *pe.COFFSymbol) (*loader.SymbolBuilder, loader.Sym, error) {
symname, err := pesym.FullName(state.f.StringTable)
if err != nil {
return nil, 0, err
}
var name string
if issect(pesym) {
name = state.l.SymName(state.sectsyms[state.f.Sections[pesym.SectionNumber-1]])
} else {
name = symname
if strings.HasPrefix(symname, "__imp_") {
orig := symname[len("__imp_"):]
if _, ok := state.defWithImp[orig]; ok {
// Don't rename __imp_XXX to XXX, since if we do this
// we'll wind up with a duplicate definition. One
// example is "__acrt_iob_func"; see commit b295099
// from git://git.code.sf.net/p/mingw-w64/mingw-w64
// for details.
} else {
name = strings.TrimPrefix(name, "__imp_") // __imp_Name => Name
}
}
// A note on the "_main" exclusion below: the main routine
// defined by the Go runtime is named "_main", not "main", so
// when reading references to _main from a host object we want
// to avoid rewriting "_main" to "main" in this specific
// instance. See #issuecomment-1143698749 on #35006 for more
// details on this problem.
if state.arch.Family == sys.I386 && name[0] == '_' && name != "_main" {
name = name[1:] // _Name => Name
}
}
// remove last @XXX
if i := strings.LastIndex(name, "@"); i >= 0 {
name = name[:i]
}
var s loader.Sym
var bld *loader.SymbolBuilder
switch pesym.Type {
default:
return nil, 0, 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 = state.l.LookupOrCreateCgoExport(name, 0)
case IMAGE_SYM_CLASS_NULL, IMAGE_SYM_CLASS_STATIC, IMAGE_SYM_CLASS_LABEL:
s = state.l.LookupOrCreateCgoExport(name, state.localSymVersion)
bld = makeUpdater(state.l, bld, s)
bld.SetDuplicateOK(true)
default:
return nil, 0, fmt.Errorf("%s: invalid symbol binding %d", symname, pesym.StorageClass)
}
}
if s != 0 && state.l.SymType(s) == 0 && (pesym.StorageClass != IMAGE_SYM_CLASS_STATIC || pesym.Value != 0) {
bld = makeUpdater(state.l, bld, s)
bld.SetType(sym.SXREF)
}
if strings.HasPrefix(symname, "__imp_") {
bld = makeUpdater(state.l, bld, s)
bld.SetGot(-2) // flag for __imp_
}
return bld, s, nil
}
// preprocessSymbols walks the COFF symbols for the PE file we're
// reading and looks for cases where we have both a symbol definition
// for "XXX" and an "__imp_XXX" symbol, recording these cases in a map
// in the state struct. This information will be used in readpesym()
// above to give such symbols special treatment. This function also
// gathers information about COMDAT sections/symbols for later use
// in readpesym().
func (state *peLoaderState) preprocessSymbols() error {
// Locate comdat sections.
state.comdats = make(map[uint16]int64)
for i, s := range state.f.Sections {
if s.Characteristics&uint32(pe.IMAGE_SCN_LNK_COMDAT) != 0 {
state.comdats[uint16(i)] = int64(s.Size)
}
}
// Examine symbol defs.
imp := make(map[string]struct{})
def := make(map[string]struct{})
for i, numaux := 0, 0; i < len(state.f.COFFSymbols); i += numaux + 1 {
pesym := &state.f.COFFSymbols[i]
numaux = int(pesym.NumberOfAuxSymbols)
if pesym.SectionNumber == 0 { // extern
continue
}
symname, err := pesym.FullName(state.f.StringTable)
if err != nil {
return err
}
def[symname] = struct{}{}
if strings.HasPrefix(symname, "__imp_") {
imp[strings.TrimPrefix(symname, "__imp_")] = struct{}{}
}
if _, isc := state.comdats[uint16(pesym.SectionNumber-1)]; !isc {
continue
}
if pesym.StorageClass != uint8(IMAGE_SYM_CLASS_STATIC) {
continue
}
// This symbol corresponds to a COMDAT section. Read the
// aux data for it.
auxsymp, err := state.f.COFFSymbolReadSectionDefAux(i)
if err != nil {
return fmt.Errorf("unable to read aux info for section def symbol %d %s: pe.COFFSymbolReadComdatInfo returns %v", i, symname, err)
}
if auxsymp.Selection == pe.IMAGE_COMDAT_SELECT_SAME_SIZE {
// This is supported.
} else if auxsymp.Selection == pe.IMAGE_COMDAT_SELECT_ANY {
// Also supported.
state.comdats[uint16(pesym.SectionNumber-1)] = int64(-1)
} else {
// We don't support any of the other strategies at the
// moment. I suspect that we may need to also support
// "associative", we'll see.
return fmt.Errorf("internal error: unsupported COMDAT selection strategy found in path=%s sec=%d strategy=%d idx=%d, please file a bug", state.pn, auxsymp.SecNum, auxsymp.Selection, i)
}
}
state.defWithImp = make(map[string]struct{})
for n := range imp {
if _, ok := def[n]; ok {
state.defWithImp[n] = struct{}{}
}
}
return nil
}
Mini Shell