Current File : //usr/local/go/src/cmd/link/internal/ld/pe.go
// 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.
// PE (Portable Executable) file writing
// https://docs.microsoft.com/en-us/windows/win32/debug/pe-format
package ld
import (
"cmd/internal/objabi"
"cmd/internal/sys"
"cmd/link/internal/loader"
"cmd/link/internal/sym"
"debug/pe"
"encoding/binary"
"fmt"
"internal/buildcfg"
"sort"
"strconv"
"strings"
)
type IMAGE_IMPORT_DESCRIPTOR struct {
OriginalFirstThunk uint32
TimeDateStamp uint32
ForwarderChain uint32
Name uint32
FirstThunk uint32
}
type IMAGE_EXPORT_DIRECTORY struct {
Characteristics uint32
TimeDateStamp uint32
MajorVersion uint16
MinorVersion uint16
Name uint32
Base uint32
NumberOfFunctions uint32
NumberOfNames uint32
AddressOfFunctions uint32
AddressOfNames uint32
AddressOfNameOrdinals uint32
}
var (
// PEBASE is the base address for the executable.
// It is small for 32-bit and large for 64-bit.
PEBASE int64
// SectionAlignment must be greater than or equal to FileAlignment.
// The default is the page size for the architecture.
PESECTALIGN int64 = 0x1000
// FileAlignment should be a power of 2 between 512 and 64 K, inclusive.
// The default is 512. If the SectionAlignment is less than
// the architecture's page size, then FileAlignment must match SectionAlignment.
PEFILEALIGN int64 = 2 << 8
)
const (
IMAGE_SCN_CNT_CODE = 0x00000020
IMAGE_SCN_CNT_INITIALIZED_DATA = 0x00000040
IMAGE_SCN_CNT_UNINITIALIZED_DATA = 0x00000080
IMAGE_SCN_LNK_OTHER = 0x00000100
IMAGE_SCN_LNK_INFO = 0x00000200
IMAGE_SCN_LNK_REMOVE = 0x00000800
IMAGE_SCN_LNK_COMDAT = 0x00001000
IMAGE_SCN_GPREL = 0x00008000
IMAGE_SCN_MEM_PURGEABLE = 0x00020000
IMAGE_SCN_MEM_16BIT = 0x00020000
IMAGE_SCN_MEM_LOCKED = 0x00040000
IMAGE_SCN_MEM_PRELOAD = 0x00080000
IMAGE_SCN_ALIGN_1BYTES = 0x00100000
IMAGE_SCN_ALIGN_2BYTES = 0x00200000
IMAGE_SCN_ALIGN_4BYTES = 0x00300000
IMAGE_SCN_ALIGN_8BYTES = 0x00400000
IMAGE_SCN_ALIGN_16BYTES = 0x00500000
IMAGE_SCN_ALIGN_32BYTES = 0x00600000
IMAGE_SCN_ALIGN_64BYTES = 0x00700000
IMAGE_SCN_ALIGN_128BYTES = 0x00800000
IMAGE_SCN_ALIGN_256BYTES = 0x00900000
IMAGE_SCN_ALIGN_512BYTES = 0x00A00000
IMAGE_SCN_ALIGN_1024BYTES = 0x00B00000
IMAGE_SCN_ALIGN_2048BYTES = 0x00C00000
IMAGE_SCN_ALIGN_4096BYTES = 0x00D00000
IMAGE_SCN_ALIGN_8192BYTES = 0x00E00000
IMAGE_SCN_LNK_NRELOC_OVFL = 0x01000000
IMAGE_SCN_MEM_DISCARDABLE = 0x02000000
IMAGE_SCN_MEM_NOT_CACHED = 0x04000000
IMAGE_SCN_MEM_NOT_PAGED = 0x08000000
IMAGE_SCN_MEM_SHARED = 0x10000000
IMAGE_SCN_MEM_EXECUTE = 0x20000000
IMAGE_SCN_MEM_READ = 0x40000000
IMAGE_SCN_MEM_WRITE = 0x80000000
)
// See https://docs.microsoft.com/en-us/windows/win32/debug/pe-format.
// TODO(crawshaw): add these constants to debug/pe.
const (
// TODO: the Microsoft doco says IMAGE_SYM_DTYPE_ARRAY is 3 and IMAGE_SYM_DTYPE_FUNCTION is 2
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
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_SECREL = 0x000F
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
IMAGE_REL_BASED_HIGHLOW = 3
IMAGE_REL_BASED_DIR64 = 10
)
const (
PeMinimumTargetMajorVersion = 6
PeMinimumTargetMinorVersion = 1
)
// DOS stub that prints out
// "This program cannot be run in DOS mode."
var dosstub = []uint8{
0x4d,
0x5a,
0x90,
0x00,
0x03,
0x00,
0x04,
0x00,
0x00,
0x00,
0x00,
0x00,
0xff,
0xff,
0x00,
0x00,
0x8b,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x40,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x80,
0x00,
0x00,
0x00,
0x0e,
0x1f,
0xba,
0x0e,
0x00,
0xb4,
0x09,
0xcd,
0x21,
0xb8,
0x01,
0x4c,
0xcd,
0x21,
0x54,
0x68,
0x69,
0x73,
0x20,
0x70,
0x72,
0x6f,
0x67,
0x72,
0x61,
0x6d,
0x20,
0x63,
0x61,
0x6e,
0x6e,
0x6f,
0x74,
0x20,
0x62,
0x65,
0x20,
0x72,
0x75,
0x6e,
0x20,
0x69,
0x6e,
0x20,
0x44,
0x4f,
0x53,
0x20,
0x6d,
0x6f,
0x64,
0x65,
0x2e,
0x0d,
0x0d,
0x0a,
0x24,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
}
type Imp struct {
s loader.Sym
off uint64
next *Imp
argsize int
}
type Dll struct {
name string
nameoff uint64
thunkoff uint64
ms *Imp
next *Dll
}
var (
rsrcsyms []loader.Sym
PESECTHEADR int32
PEFILEHEADR int32
pe64 int
dr *Dll
dexport = make([]loader.Sym, 0, 1024)
)
// peStringTable is a COFF string table.
type peStringTable struct {
strings []string
stringsLen int
}
// size returns size of string table t.
func (t *peStringTable) size() int {
// string table starts with 4-byte length at the beginning
return t.stringsLen + 4
}
// add adds string str to string table t.
func (t *peStringTable) add(str string) int {
off := t.size()
t.strings = append(t.strings, str)
t.stringsLen += len(str) + 1 // each string will have 0 appended to it
return off
}
// write writes string table t into the output file.
func (t *peStringTable) write(out *OutBuf) {
out.Write32(uint32(t.size()))
for _, s := range t.strings {
out.WriteString(s)
out.Write8(0)
}
}
// peSection represents section from COFF section table.
type peSection struct {
name string
shortName string
index int // one-based index into the Section Table
virtualSize uint32
virtualAddress uint32
sizeOfRawData uint32
pointerToRawData uint32
pointerToRelocations uint32
numberOfRelocations uint16
characteristics uint32
}
// checkOffset verifies COFF section sect offset in the file.
func (sect *peSection) checkOffset(off int64) {
if off != int64(sect.pointerToRawData) {
Errorf(nil, "%s.PointerToRawData = %#x, want %#x", sect.name, uint64(int64(sect.pointerToRawData)), uint64(off))
errorexit()
}
}
// checkSegment verifies COFF section sect matches address
// and file offset provided in segment seg.
func (sect *peSection) checkSegment(seg *sym.Segment) {
if seg.Vaddr-uint64(PEBASE) != uint64(sect.virtualAddress) {
Errorf(nil, "%s.VirtualAddress = %#x, want %#x", sect.name, uint64(int64(sect.virtualAddress)), uint64(int64(seg.Vaddr-uint64(PEBASE))))
errorexit()
}
if seg.Fileoff != uint64(sect.pointerToRawData) {
Errorf(nil, "%s.PointerToRawData = %#x, want %#x", sect.name, uint64(int64(sect.pointerToRawData)), uint64(int64(seg.Fileoff)))
errorexit()
}
}
// pad adds zeros to the section sect. It writes as many bytes
// as necessary to make section sect.SizeOfRawData bytes long.
// It assumes that n bytes are already written to the file.
func (sect *peSection) pad(out *OutBuf, n uint32) {
out.WriteStringN("", int(sect.sizeOfRawData-n))
}
// write writes COFF section sect into the output file.
func (sect *peSection) write(out *OutBuf, linkmode LinkMode) error {
h := pe.SectionHeader32{
VirtualSize: sect.virtualSize,
SizeOfRawData: sect.sizeOfRawData,
PointerToRawData: sect.pointerToRawData,
PointerToRelocations: sect.pointerToRelocations,
NumberOfRelocations: sect.numberOfRelocations,
Characteristics: sect.characteristics,
}
if linkmode != LinkExternal {
h.VirtualAddress = sect.virtualAddress
}
copy(h.Name[:], sect.shortName)
return binary.Write(out, binary.LittleEndian, h)
}
// emitRelocations emits the relocation entries for the sect.
// The actual relocations are emitted by relocfn.
// This updates the corresponding PE section table entry
// with the relocation offset and count.
func (sect *peSection) emitRelocations(out *OutBuf, relocfn func() int) {
sect.pointerToRelocations = uint32(out.Offset())
// first entry: extended relocs
out.Write32(0) // placeholder for number of relocation + 1
out.Write32(0)
out.Write16(0)
n := relocfn() + 1
cpos := out.Offset()
out.SeekSet(int64(sect.pointerToRelocations))
out.Write32(uint32(n))
out.SeekSet(cpos)
if n > 0x10000 {
n = 0x10000
sect.characteristics |= IMAGE_SCN_LNK_NRELOC_OVFL
} else {
sect.pointerToRelocations += 10 // skip the extend reloc entry
}
sect.numberOfRelocations = uint16(n - 1)
}
// peFile is used to build COFF file.
type peFile struct {
sections []*peSection
stringTable peStringTable
textSect *peSection
rdataSect *peSection
dataSect *peSection
bssSect *peSection
ctorsSect *peSection
nextSectOffset uint32
nextFileOffset uint32
symtabOffset int64 // offset to the start of symbol table
symbolCount int // number of symbol table records written
dataDirectory [16]pe.DataDirectory
}
// addSection adds section to the COFF file f.
func (f *peFile) addSection(name string, sectsize int, filesize int) *peSection {
sect := &peSection{
name: name,
shortName: name,
index: len(f.sections) + 1,
virtualAddress: f.nextSectOffset,
pointerToRawData: f.nextFileOffset,
}
f.nextSectOffset = uint32(Rnd(int64(f.nextSectOffset)+int64(sectsize), PESECTALIGN))
if filesize > 0 {
sect.virtualSize = uint32(sectsize)
sect.sizeOfRawData = uint32(Rnd(int64(filesize), PEFILEALIGN))
f.nextFileOffset += sect.sizeOfRawData
} else {
sect.sizeOfRawData = uint32(sectsize)
}
f.sections = append(f.sections, sect)
return sect
}
// addDWARFSection adds DWARF section to the COFF file f.
// This function is similar to addSection, but DWARF section names are
// longer than 8 characters, so they need to be stored in the string table.
func (f *peFile) addDWARFSection(name string, size int) *peSection {
if size == 0 {
Exitf("DWARF section %q is empty", name)
}
// DWARF section names are longer than 8 characters.
// PE format requires such names to be stored in string table,
// and section names replaced with slash (/) followed by
// correspondent string table index.
// see http://www.microsoft.com/whdc/system/platform/firmware/PECOFFdwn.mspx
// for details
off := f.stringTable.add(name)
h := f.addSection(name, size, size)
h.shortName = fmt.Sprintf("/%d", off)
h.characteristics = IMAGE_SCN_ALIGN_1BYTES | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_DISCARDABLE | IMAGE_SCN_CNT_INITIALIZED_DATA
return h
}
// addDWARF adds DWARF information to the COFF file f.
func (f *peFile) addDWARF() {
if *FlagS { // disable symbol table
return
}
if *FlagW { // disable dwarf
return
}
for _, sect := range Segdwarf.Sections {
h := f.addDWARFSection(sect.Name, int(sect.Length))
fileoff := sect.Vaddr - Segdwarf.Vaddr + Segdwarf.Fileoff
if uint64(h.pointerToRawData) != fileoff {
Exitf("%s.PointerToRawData = %#x, want %#x", sect.Name, h.pointerToRawData, fileoff)
}
}
}
// addInitArray adds .ctors COFF section to the file f.
func (f *peFile) addInitArray(ctxt *Link) *peSection {
// The size below was determined by the specification for array relocations,
// and by observing what GCC writes here. If the initarray section grows to
// contain more than one constructor entry, the size will need to be 8 * constructor_count.
// However, the entire Go runtime is initialized from just one function, so it is unlikely
// that this will need to grow in the future.
var size int
var alignment uint32
switch buildcfg.GOARCH {
default:
Exitf("peFile.addInitArray: unsupported GOARCH=%q\n", buildcfg.GOARCH)
case "386", "arm":
size = 4
alignment = IMAGE_SCN_ALIGN_4BYTES
case "amd64", "arm64":
size = 8
alignment = IMAGE_SCN_ALIGN_8BYTES
}
sect := f.addSection(".ctors", size, size)
sect.characteristics = IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE | alignment
sect.sizeOfRawData = uint32(size)
ctxt.Out.SeekSet(int64(sect.pointerToRawData))
sect.checkOffset(ctxt.Out.Offset())
init_entry := ctxt.loader.Lookup(*flagEntrySymbol, 0)
addr := uint64(ctxt.loader.SymValue(init_entry)) - ctxt.loader.SymSect(init_entry).Vaddr
switch buildcfg.GOARCH {
case "386", "arm":
ctxt.Out.Write32(uint32(addr))
case "amd64", "arm64":
ctxt.Out.Write64(addr)
}
return sect
}
// emitRelocations emits relocation entries for go.o in external linking.
func (f *peFile) emitRelocations(ctxt *Link) {
for ctxt.Out.Offset()&7 != 0 {
ctxt.Out.Write8(0)
}
ldr := ctxt.loader
// relocsect relocates symbols from first in section sect, and returns
// the total number of relocations emitted.
relocsect := func(sect *sym.Section, syms []loader.Sym, base uint64) int {
// If main section has no bits, nothing to relocate.
if sect.Vaddr >= sect.Seg.Vaddr+sect.Seg.Filelen {
return 0
}
sect.Reloff = uint64(ctxt.Out.Offset())
for i, s := range syms {
if !ldr.AttrReachable(s) {
continue
}
if uint64(ldr.SymValue(s)) >= sect.Vaddr {
syms = syms[i:]
break
}
}
eaddr := int64(sect.Vaddr + sect.Length)
for _, s := range syms {
if !ldr.AttrReachable(s) {
continue
}
if ldr.SymValue(s) >= eaddr {
break
}
// Compute external relocations on the go, and pass to PEreloc1
// to stream out.
relocs := ldr.Relocs(s)
for ri := 0; ri < relocs.Count(); ri++ {
r := relocs.At(ri)
rr, ok := extreloc(ctxt, ldr, s, r)
if !ok {
continue
}
if rr.Xsym == 0 {
ctxt.Errorf(s, "missing xsym in relocation")
continue
}
if ldr.SymDynid(rr.Xsym) < 0 {
ctxt.Errorf(s, "reloc %d to non-coff symbol %s (outer=%s) %d", r.Type(), ldr.SymName(r.Sym()), ldr.SymName(rr.Xsym), ldr.SymType(r.Sym()))
}
if !thearch.PEreloc1(ctxt.Arch, ctxt.Out, ldr, s, rr, int64(uint64(ldr.SymValue(s)+int64(r.Off()))-base)) {
ctxt.Errorf(s, "unsupported obj reloc %v/%d to %s", r.Type(), r.Siz(), ldr.SymName(r.Sym()))
}
}
}
sect.Rellen = uint64(ctxt.Out.Offset()) - sect.Reloff
const relocLen = 4 + 4 + 2
return int(sect.Rellen / relocLen)
}
sects := []struct {
peSect *peSection
seg *sym.Segment
syms []loader.Sym
}{
{f.textSect, &Segtext, ctxt.Textp},
{f.rdataSect, &Segrodata, ctxt.datap},
{f.dataSect, &Segdata, ctxt.datap},
}
for _, s := range sects {
s.peSect.emitRelocations(ctxt.Out, func() int {
var n int
for _, sect := range s.seg.Sections {
n += relocsect(sect, s.syms, s.seg.Vaddr)
}
return n
})
}
dwarfLoop:
for i := 0; i < len(Segdwarf.Sections); i++ {
sect := Segdwarf.Sections[i]
si := dwarfp[i]
if si.secSym() != loader.Sym(sect.Sym) ||
ldr.SymSect(si.secSym()) != sect {
panic("inconsistency between dwarfp and Segdwarf")
}
for _, pesect := range f.sections {
if sect.Name == pesect.name {
pesect.emitRelocations(ctxt.Out, func() int {
return relocsect(sect, si.syms, sect.Vaddr)
})
continue dwarfLoop
}
}
Errorf(nil, "emitRelocations: could not find %q section", sect.Name)
}
if f.ctorsSect == nil {
return
}
f.ctorsSect.emitRelocations(ctxt.Out, func() int {
dottext := ldr.Lookup(".text", 0)
ctxt.Out.Write32(0)
ctxt.Out.Write32(uint32(ldr.SymDynid(dottext)))
switch buildcfg.GOARCH {
default:
ctxt.Errorf(dottext, "unknown architecture for PE: %q\n", buildcfg.GOARCH)
case "386":
ctxt.Out.Write16(IMAGE_REL_I386_DIR32)
case "amd64":
ctxt.Out.Write16(IMAGE_REL_AMD64_ADDR64)
case "arm":
ctxt.Out.Write16(IMAGE_REL_ARM_ADDR32)
case "arm64":
ctxt.Out.Write16(IMAGE_REL_ARM64_ADDR64)
}
return 1
})
}
// writeSymbol appends symbol s to file f symbol table.
// It also sets s.Dynid to written symbol number.
func (f *peFile) writeSymbol(out *OutBuf, ldr *loader.Loader, s loader.Sym, name string, value int64, sectidx int, typ uint16, class uint8) {
if len(name) > 8 {
out.Write32(0)
out.Write32(uint32(f.stringTable.add(name)))
} else {
out.WriteStringN(name, 8)
}
out.Write32(uint32(value))
out.Write16(uint16(sectidx))
out.Write16(typ)
out.Write8(class)
out.Write8(0) // no aux entries
ldr.SetSymDynid(s, int32(f.symbolCount))
f.symbolCount++
}
// mapToPESection searches peFile f for s symbol's location.
// It returns PE section index, and offset within that section.
func (f *peFile) mapToPESection(ldr *loader.Loader, s loader.Sym, linkmode LinkMode) (pesectidx int, offset int64, err error) {
sect := ldr.SymSect(s)
if sect == nil {
return 0, 0, fmt.Errorf("could not map %s symbol with no section", ldr.SymName(s))
}
if sect.Seg == &Segtext {
return f.textSect.index, int64(uint64(ldr.SymValue(s)) - Segtext.Vaddr), nil
}
if sect.Seg == &Segrodata {
return f.rdataSect.index, int64(uint64(ldr.SymValue(s)) - Segrodata.Vaddr), nil
}
if sect.Seg != &Segdata {
return 0, 0, fmt.Errorf("could not map %s symbol with non .text or .rdata or .data section", ldr.SymName(s))
}
v := uint64(ldr.SymValue(s)) - Segdata.Vaddr
if linkmode != LinkExternal {
return f.dataSect.index, int64(v), nil
}
if ldr.SymType(s) == sym.SDATA {
return f.dataSect.index, int64(v), nil
}
// Note: although address of runtime.edata (type sym.SDATA) is at the start of .bss section
// it still belongs to the .data section, not the .bss section.
if v < Segdata.Filelen {
return f.dataSect.index, int64(v), nil
}
return f.bssSect.index, int64(v - Segdata.Filelen), nil
}
var isLabel = make(map[loader.Sym]bool)
func AddPELabelSym(ldr *loader.Loader, s loader.Sym) {
isLabel[s] = true
}
// writeSymbols writes all COFF symbol table records.
func (f *peFile) writeSymbols(ctxt *Link) {
ldr := ctxt.loader
addsym := func(s loader.Sym) {
t := ldr.SymType(s)
if ldr.SymSect(s) == nil && t != sym.SDYNIMPORT && t != sym.SHOSTOBJ && t != sym.SUNDEFEXT {
return
}
name := ldr.SymName(s)
// Only windows/386 requires underscore prefix on external symbols.
if ctxt.Is386() && ctxt.IsExternal() &&
(t == sym.SHOSTOBJ || t == sym.SUNDEFEXT || ldr.AttrCgoExport(s)) {
name = "_" + name
}
name = mangleABIName(ctxt, ldr, s, name)
var peSymType uint16
if ctxt.IsExternal() {
peSymType = IMAGE_SYM_TYPE_NULL
} else {
// TODO: fix IMAGE_SYM_DTYPE_ARRAY value and use following expression, instead of 0x0308
// peSymType = IMAGE_SYM_DTYPE_ARRAY<<8 + IMAGE_SYM_TYPE_STRUCT
peSymType = 0x0308 // "array of structs"
}
sect, value, err := f.mapToPESection(ldr, s, ctxt.LinkMode)
if err != nil {
if t == sym.SDYNIMPORT || t == sym.SHOSTOBJ || t == sym.SUNDEFEXT {
peSymType = IMAGE_SYM_DTYPE_FUNCTION
} else {
ctxt.Errorf(s, "addpesym: %v", err)
}
}
class := IMAGE_SYM_CLASS_EXTERNAL
if ldr.IsFileLocal(s) || ldr.AttrVisibilityHidden(s) || ldr.AttrLocal(s) {
class = IMAGE_SYM_CLASS_STATIC
}
f.writeSymbol(ctxt.Out, ldr, s, name, value, sect, peSymType, uint8(class))
}
if ctxt.LinkMode == LinkExternal {
// Include section symbols as external, because
// .ctors and .debug_* section relocations refer to it.
for _, pesect := range f.sections {
s := ldr.LookupOrCreateSym(pesect.name, 0)
f.writeSymbol(ctxt.Out, ldr, s, pesect.name, 0, pesect.index, IMAGE_SYM_TYPE_NULL, IMAGE_SYM_CLASS_STATIC)
}
}
// Add special runtime.text and runtime.etext symbols.
s := ldr.Lookup("runtime.text", 0)
if ldr.SymType(s) == sym.STEXT {
addsym(s)
}
s = ldr.Lookup("runtime.etext", 0)
if ldr.SymType(s) == sym.STEXT {
addsym(s)
}
// Add text symbols.
for _, s := range ctxt.Textp {
addsym(s)
}
shouldBeInSymbolTable := func(s loader.Sym) bool {
if ldr.AttrNotInSymbolTable(s) {
return false
}
name := ldr.RawSymName(s) // TODO: try not to read the name
if name == "" || name[0] == '.' {
return false
}
return true
}
// Add data symbols and external references.
for s := loader.Sym(1); s < loader.Sym(ldr.NSym()); s++ {
if !ldr.AttrReachable(s) {
continue
}
t := ldr.SymType(s)
if t >= sym.SELFRXSECT && t < sym.SXREF { // data sections handled in dodata
if t == sym.STLSBSS {
continue
}
if !shouldBeInSymbolTable(s) {
continue
}
addsym(s)
}
switch t {
case sym.SDYNIMPORT, sym.SHOSTOBJ, sym.SUNDEFEXT:
addsym(s)
default:
if len(isLabel) > 0 && isLabel[s] {
addsym(s)
}
}
}
}
// writeSymbolTableAndStringTable writes out symbol and string tables for peFile f.
func (f *peFile) writeSymbolTableAndStringTable(ctxt *Link) {
f.symtabOffset = ctxt.Out.Offset()
// write COFF symbol table
if !*FlagS || ctxt.LinkMode == LinkExternal {
f.writeSymbols(ctxt)
}
// update COFF file header and section table
size := f.stringTable.size() + 18*f.symbolCount
var h *peSection
if ctxt.LinkMode != LinkExternal {
// We do not really need .symtab for go.o, and if we have one, ld
// will also include it in the exe, and that will confuse windows.
h = f.addSection(".symtab", size, size)
h.characteristics = IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_DISCARDABLE
h.checkOffset(f.symtabOffset)
}
// write COFF string table
f.stringTable.write(ctxt.Out)
if ctxt.LinkMode != LinkExternal {
h.pad(ctxt.Out, uint32(size))
}
}
// writeFileHeader writes COFF file header for peFile f.
func (f *peFile) writeFileHeader(ctxt *Link) {
var fh pe.FileHeader
switch ctxt.Arch.Family {
default:
Exitf("unknown PE architecture: %v", ctxt.Arch.Family)
case sys.AMD64:
fh.Machine = pe.IMAGE_FILE_MACHINE_AMD64
case sys.I386:
fh.Machine = pe.IMAGE_FILE_MACHINE_I386
case sys.ARM:
fh.Machine = pe.IMAGE_FILE_MACHINE_ARMNT
case sys.ARM64:
fh.Machine = pe.IMAGE_FILE_MACHINE_ARM64
}
fh.NumberOfSections = uint16(len(f.sections))
// Being able to produce identical output for identical input is
// much more beneficial than having build timestamp in the header.
fh.TimeDateStamp = 0
if ctxt.LinkMode == LinkExternal {
fh.Characteristics = pe.IMAGE_FILE_LINE_NUMS_STRIPPED
} else {
fh.Characteristics = pe.IMAGE_FILE_EXECUTABLE_IMAGE | pe.IMAGE_FILE_DEBUG_STRIPPED
switch ctxt.Arch.Family {
case sys.AMD64, sys.I386:
if ctxt.BuildMode != BuildModePIE {
fh.Characteristics |= pe.IMAGE_FILE_RELOCS_STRIPPED
}
}
}
if pe64 != 0 {
var oh64 pe.OptionalHeader64
fh.SizeOfOptionalHeader = uint16(binary.Size(&oh64))
fh.Characteristics |= pe.IMAGE_FILE_LARGE_ADDRESS_AWARE
} else {
var oh pe.OptionalHeader32
fh.SizeOfOptionalHeader = uint16(binary.Size(&oh))
fh.Characteristics |= pe.IMAGE_FILE_32BIT_MACHINE
}
fh.PointerToSymbolTable = uint32(f.symtabOffset)
fh.NumberOfSymbols = uint32(f.symbolCount)
binary.Write(ctxt.Out, binary.LittleEndian, &fh)
}
// writeOptionalHeader writes COFF optional header for peFile f.
func (f *peFile) writeOptionalHeader(ctxt *Link) {
var oh pe.OptionalHeader32
var oh64 pe.OptionalHeader64
if pe64 != 0 {
oh64.Magic = 0x20b // PE32+
} else {
oh.Magic = 0x10b // PE32
oh.BaseOfData = f.dataSect.virtualAddress
}
// Fill out both oh64 and oh. We only use one. Oh well.
oh64.MajorLinkerVersion = 3
oh.MajorLinkerVersion = 3
oh64.MinorLinkerVersion = 0
oh.MinorLinkerVersion = 0
oh64.SizeOfCode = f.textSect.sizeOfRawData
oh.SizeOfCode = f.textSect.sizeOfRawData
oh64.SizeOfInitializedData = f.dataSect.sizeOfRawData
oh.SizeOfInitializedData = f.dataSect.sizeOfRawData
oh64.SizeOfUninitializedData = 0
oh.SizeOfUninitializedData = 0
if ctxt.LinkMode != LinkExternal {
oh64.AddressOfEntryPoint = uint32(Entryvalue(ctxt) - PEBASE)
oh.AddressOfEntryPoint = uint32(Entryvalue(ctxt) - PEBASE)
}
oh64.BaseOfCode = f.textSect.virtualAddress
oh.BaseOfCode = f.textSect.virtualAddress
oh64.ImageBase = uint64(PEBASE)
oh.ImageBase = uint32(PEBASE)
oh64.SectionAlignment = uint32(PESECTALIGN)
oh.SectionAlignment = uint32(PESECTALIGN)
oh64.FileAlignment = uint32(PEFILEALIGN)
oh.FileAlignment = uint32(PEFILEALIGN)
oh64.MajorOperatingSystemVersion = PeMinimumTargetMajorVersion
oh.MajorOperatingSystemVersion = PeMinimumTargetMajorVersion
oh64.MinorOperatingSystemVersion = PeMinimumTargetMinorVersion
oh.MinorOperatingSystemVersion = PeMinimumTargetMinorVersion
oh64.MajorImageVersion = 1
oh.MajorImageVersion = 1
oh64.MinorImageVersion = 0
oh.MinorImageVersion = 0
oh64.MajorSubsystemVersion = PeMinimumTargetMajorVersion
oh.MajorSubsystemVersion = PeMinimumTargetMajorVersion
oh64.MinorSubsystemVersion = PeMinimumTargetMinorVersion
oh.MinorSubsystemVersion = PeMinimumTargetMinorVersion
oh64.SizeOfImage = f.nextSectOffset
oh.SizeOfImage = f.nextSectOffset
oh64.SizeOfHeaders = uint32(PEFILEHEADR)
oh.SizeOfHeaders = uint32(PEFILEHEADR)
if windowsgui {
oh64.Subsystem = pe.IMAGE_SUBSYSTEM_WINDOWS_GUI
oh.Subsystem = pe.IMAGE_SUBSYSTEM_WINDOWS_GUI
} else {
oh64.Subsystem = pe.IMAGE_SUBSYSTEM_WINDOWS_CUI
oh.Subsystem = pe.IMAGE_SUBSYSTEM_WINDOWS_CUI
}
// Mark as having awareness of terminal services, to avoid ancient compatibility hacks.
oh64.DllCharacteristics |= pe.IMAGE_DLLCHARACTERISTICS_TERMINAL_SERVER_AWARE
oh.DllCharacteristics |= pe.IMAGE_DLLCHARACTERISTICS_TERMINAL_SERVER_AWARE
// Enable DEP
oh64.DllCharacteristics |= pe.IMAGE_DLLCHARACTERISTICS_NX_COMPAT
oh.DllCharacteristics |= pe.IMAGE_DLLCHARACTERISTICS_NX_COMPAT
// The DLL can be relocated at load time.
if needPEBaseReloc(ctxt) {
oh64.DllCharacteristics |= pe.IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE
oh.DllCharacteristics |= pe.IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE
}
// Image can handle a high entropy 64-bit virtual address space.
if ctxt.BuildMode == BuildModePIE {
oh64.DllCharacteristics |= pe.IMAGE_DLLCHARACTERISTICS_HIGH_ENTROPY_VA
}
// Disable stack growth as we don't want Windows to
// fiddle with the thread stack limits, which we set
// ourselves to circumvent the stack checks in the
// Windows exception dispatcher.
// Commit size must be strictly less than reserve
// size otherwise reserve will be rounded up to a
// larger size, as verified with VMMap.
// On 64-bit, we always reserve 2MB stacks. "Pure" Go code is
// okay with much smaller stacks, but the syscall package
// makes it easy to call into arbitrary C code without cgo,
// and system calls even in "pure" Go code are actually C
// calls that may need more stack than we think.
//
// The default stack reserve size directly affects only the main
// thread.
//
// For other threads, the runtime explicitly asks the kernel
// to use the default stack size so that all stacks are
// consistent.
//
// At thread start, in minit, the runtime queries the OS for
// the actual stack bounds so that the stack size doesn't need
// to be hard-coded into the runtime.
oh64.SizeOfStackReserve = 0x00200000
if !iscgo {
oh64.SizeOfStackCommit = 0x00001000
} else {
// TODO(brainman): Maybe remove optional header writing altogether for cgo.
// For cgo it is the external linker that is building final executable.
// And it probably does not use any information stored in optional header.
oh64.SizeOfStackCommit = 0x00200000 - 0x2000 // account for 2 guard pages
}
oh.SizeOfStackReserve = 0x00100000
if !iscgo {
oh.SizeOfStackCommit = 0x00001000
} else {
oh.SizeOfStackCommit = 0x00100000 - 0x2000 // account for 2 guard pages
}
oh64.SizeOfHeapReserve = 0x00100000
oh.SizeOfHeapReserve = 0x00100000
oh64.SizeOfHeapCommit = 0x00001000
oh.SizeOfHeapCommit = 0x00001000
oh64.NumberOfRvaAndSizes = 16
oh.NumberOfRvaAndSizes = 16
if pe64 != 0 {
oh64.DataDirectory = f.dataDirectory
} else {
oh.DataDirectory = f.dataDirectory
}
if pe64 != 0 {
binary.Write(ctxt.Out, binary.LittleEndian, &oh64)
} else {
binary.Write(ctxt.Out, binary.LittleEndian, &oh)
}
}
var pefile peFile
func Peinit(ctxt *Link) {
var l int
if ctxt.Arch.PtrSize == 8 {
// 64-bit architectures
pe64 = 1
PEBASE = 1 << 32
if ctxt.Arch.Family == sys.AMD64 {
// TODO(rsc): For cgo we currently use 32-bit relocations
// that fail when PEBASE is too large.
// We need to fix this, but for now, use a smaller PEBASE.
PEBASE = 1 << 22
}
var oh64 pe.OptionalHeader64
l = binary.Size(&oh64)
} else {
// 32-bit architectures
PEBASE = 1 << 22
var oh pe.OptionalHeader32
l = binary.Size(&oh)
}
if ctxt.LinkMode == LinkExternal {
// .rdata section will contain "masks" and "shifts" symbols, and they
// need to be aligned to 16-bytes. So make all sections aligned
// to 32-byte and mark them all IMAGE_SCN_ALIGN_32BYTES so external
// linker will honour that requirement.
PESECTALIGN = 32
PEFILEALIGN = 0
}
var sh [16]pe.SectionHeader32
var fh pe.FileHeader
PEFILEHEADR = int32(Rnd(int64(len(dosstub)+binary.Size(&fh)+l+binary.Size(&sh)), PEFILEALIGN))
if ctxt.LinkMode != LinkExternal {
PESECTHEADR = int32(Rnd(int64(PEFILEHEADR), PESECTALIGN))
} else {
PESECTHEADR = 0
}
pefile.nextSectOffset = uint32(PESECTHEADR)
pefile.nextFileOffset = uint32(PEFILEHEADR)
if ctxt.LinkMode == LinkInternal {
// some mingw libs depend on this symbol, for example, FindPESectionByName
for _, name := range [2]string{"__image_base__", "_image_base__"} {
sb := ctxt.loader.CreateSymForUpdate(name, 0)
sb.SetType(sym.SDATA)
sb.SetValue(PEBASE)
ctxt.loader.SetAttrSpecial(sb.Sym(), true)
ctxt.loader.SetAttrLocal(sb.Sym(), true)
}
}
HEADR = PEFILEHEADR
if *FlagTextAddr == -1 {
*FlagTextAddr = PEBASE + int64(PESECTHEADR)
}
if *FlagRound == -1 {
*FlagRound = int(PESECTALIGN)
}
}
func pewrite(ctxt *Link) {
ctxt.Out.SeekSet(0)
if ctxt.LinkMode != LinkExternal {
ctxt.Out.Write(dosstub)
ctxt.Out.WriteStringN("PE", 4)
}
pefile.writeFileHeader(ctxt)
pefile.writeOptionalHeader(ctxt)
for _, sect := range pefile.sections {
sect.write(ctxt.Out, ctxt.LinkMode)
}
}
func strput(out *OutBuf, s string) {
out.WriteString(s)
out.Write8(0)
// string must be padded to even size
if (len(s)+1)%2 != 0 {
out.Write8(0)
}
}
func initdynimport(ctxt *Link) *Dll {
ldr := ctxt.loader
var d *Dll
dr = nil
var m *Imp
for s := loader.Sym(1); s < loader.Sym(ldr.NSym()); s++ {
if !ldr.AttrReachable(s) || ldr.SymType(s) != sym.SDYNIMPORT {
continue
}
dynlib := ldr.SymDynimplib(s)
for d = dr; d != nil; d = d.next {
if d.name == dynlib {
m = new(Imp)
break
}
}
if d == nil {
d = new(Dll)
d.name = dynlib
d.next = dr
dr = d
m = new(Imp)
}
// Because external link requires properly stdcall decorated name,
// all external symbols in runtime use %n to denote that the number
// of uinptrs this function consumes. Store the argsize and discard
// the %n suffix if any.
m.argsize = -1
extName := ldr.SymExtname(s)
if i := strings.IndexByte(extName, '%'); i >= 0 {
var err error
m.argsize, err = strconv.Atoi(extName[i+1:])
if err != nil {
ctxt.Errorf(s, "failed to parse stdcall decoration: %v", err)
}
m.argsize *= ctxt.Arch.PtrSize
ldr.SetSymExtname(s, extName[:i])
}
m.s = s
m.next = d.ms
d.ms = m
}
if ctxt.IsExternal() {
// Add real symbol name
for d := dr; d != nil; d = d.next {
for m = d.ms; m != nil; m = m.next {
sb := ldr.MakeSymbolUpdater(m.s)
sb.SetType(sym.SDATA)
sb.Grow(int64(ctxt.Arch.PtrSize))
dynName := sb.Extname()
// only windows/386 requires stdcall decoration
if ctxt.Is386() && m.argsize >= 0 {
dynName += fmt.Sprintf("@%d", m.argsize)
}
dynSym := ldr.CreateSymForUpdate(dynName, 0)
dynSym.SetType(sym.SHOSTOBJ)
r, _ := sb.AddRel(objabi.R_ADDR)
r.SetSym(dynSym.Sym())
r.SetSiz(uint8(ctxt.Arch.PtrSize))
}
}
} else {
dynamic := ldr.CreateSymForUpdate(".windynamic", 0)
dynamic.SetType(sym.SWINDOWS)
for d := dr; d != nil; d = d.next {
for m = d.ms; m != nil; m = m.next {
sb := ldr.MakeSymbolUpdater(m.s)
sb.SetType(sym.SWINDOWS)
sb.SetValue(dynamic.Size())
dynamic.SetSize(dynamic.Size() + int64(ctxt.Arch.PtrSize))
dynamic.AddInteriorSym(m.s)
}
dynamic.SetSize(dynamic.Size() + int64(ctxt.Arch.PtrSize))
}
}
return dr
}
// peimporteddlls returns the gcc command line argument to link all imported
// DLLs.
func peimporteddlls() []string {
var dlls []string
for d := dr; d != nil; d = d.next {
dlls = append(dlls, "-l"+strings.TrimSuffix(d.name, ".dll"))
}
return dlls
}
func addimports(ctxt *Link, datsect *peSection) {
ldr := ctxt.loader
startoff := ctxt.Out.Offset()
dynamic := ldr.LookupOrCreateSym(".windynamic", 0)
// skip import descriptor table (will write it later)
n := uint64(0)
for d := dr; d != nil; d = d.next {
n++
}
ctxt.Out.SeekSet(startoff + int64(binary.Size(&IMAGE_IMPORT_DESCRIPTOR{}))*int64(n+1))
// write dll names
for d := dr; d != nil; d = d.next {
d.nameoff = uint64(ctxt.Out.Offset()) - uint64(startoff)
strput(ctxt.Out, d.name)
}
// write function names
for d := dr; d != nil; d = d.next {
for m := d.ms; m != nil; m = m.next {
m.off = uint64(pefile.nextSectOffset) + uint64(ctxt.Out.Offset()) - uint64(startoff)
ctxt.Out.Write16(0) // hint
strput(ctxt.Out, ldr.SymExtname(m.s))
}
}
// write OriginalFirstThunks
oftbase := uint64(ctxt.Out.Offset()) - uint64(startoff)
n = uint64(ctxt.Out.Offset())
for d := dr; d != nil; d = d.next {
d.thunkoff = uint64(ctxt.Out.Offset()) - n
for m := d.ms; m != nil; m = m.next {
if pe64 != 0 {
ctxt.Out.Write64(m.off)
} else {
ctxt.Out.Write32(uint32(m.off))
}
}
if pe64 != 0 {
ctxt.Out.Write64(0)
} else {
ctxt.Out.Write32(0)
}
}
// add pe section and pad it at the end
n = uint64(ctxt.Out.Offset()) - uint64(startoff)
isect := pefile.addSection(".idata", int(n), int(n))
isect.characteristics = IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE
isect.checkOffset(startoff)
isect.pad(ctxt.Out, uint32(n))
endoff := ctxt.Out.Offset()
// write FirstThunks (allocated in .data section)
ftbase := uint64(ldr.SymValue(dynamic)) - uint64(datsect.virtualAddress) - uint64(PEBASE)
ctxt.Out.SeekSet(int64(uint64(datsect.pointerToRawData) + ftbase))
for d := dr; d != nil; d = d.next {
for m := d.ms; m != nil; m = m.next {
if pe64 != 0 {
ctxt.Out.Write64(m.off)
} else {
ctxt.Out.Write32(uint32(m.off))
}
}
if pe64 != 0 {
ctxt.Out.Write64(0)
} else {
ctxt.Out.Write32(0)
}
}
// finally write import descriptor table
out := ctxt.Out
out.SeekSet(startoff)
for d := dr; d != nil; d = d.next {
out.Write32(uint32(uint64(isect.virtualAddress) + oftbase + d.thunkoff))
out.Write32(0)
out.Write32(0)
out.Write32(uint32(uint64(isect.virtualAddress) + d.nameoff))
out.Write32(uint32(uint64(datsect.virtualAddress) + ftbase + d.thunkoff))
}
out.Write32(0) //end
out.Write32(0)
out.Write32(0)
out.Write32(0)
out.Write32(0)
// update data directory
pefile.dataDirectory[pe.IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress = isect.virtualAddress
pefile.dataDirectory[pe.IMAGE_DIRECTORY_ENTRY_IMPORT].Size = isect.virtualSize
pefile.dataDirectory[pe.IMAGE_DIRECTORY_ENTRY_IAT].VirtualAddress = uint32(ldr.SymValue(dynamic) - PEBASE)
pefile.dataDirectory[pe.IMAGE_DIRECTORY_ENTRY_IAT].Size = uint32(ldr.SymSize(dynamic))
out.SeekSet(endoff)
}
func initdynexport(ctxt *Link) {
ldr := ctxt.loader
for s := loader.Sym(1); s < loader.Sym(ldr.NSym()); s++ {
if !ldr.AttrReachable(s) || !ldr.AttrCgoExportDynamic(s) {
continue
}
if len(dexport)+1 > cap(dexport) {
ctxt.Errorf(s, "pe dynexport table is full")
errorexit()
}
dexport = append(dexport, s)
}
sort.Slice(dexport, func(i, j int) bool { return ldr.SymExtname(dexport[i]) < ldr.SymExtname(dexport[j]) })
}
func addexports(ctxt *Link) {
ldr := ctxt.loader
var e IMAGE_EXPORT_DIRECTORY
nexport := len(dexport)
size := binary.Size(&e) + 10*nexport + len(*flagOutfile) + 1
for _, s := range dexport {
size += len(ldr.SymExtname(s)) + 1
}
if nexport == 0 {
return
}
sect := pefile.addSection(".edata", size, size)
sect.characteristics = IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ
sect.checkOffset(ctxt.Out.Offset())
va := int(sect.virtualAddress)
pefile.dataDirectory[pe.IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress = uint32(va)
pefile.dataDirectory[pe.IMAGE_DIRECTORY_ENTRY_EXPORT].Size = sect.virtualSize
vaName := va + binary.Size(&e) + nexport*4
vaAddr := va + binary.Size(&e)
vaNa := va + binary.Size(&e) + nexport*8
e.Characteristics = 0
e.MajorVersion = 0
e.MinorVersion = 0
e.NumberOfFunctions = uint32(nexport)
e.NumberOfNames = uint32(nexport)
e.Name = uint32(va+binary.Size(&e)) + uint32(nexport)*10 // Program names.
e.Base = 1
e.AddressOfFunctions = uint32(vaAddr)
e.AddressOfNames = uint32(vaName)
e.AddressOfNameOrdinals = uint32(vaNa)
out := ctxt.Out
// put IMAGE_EXPORT_DIRECTORY
binary.Write(out, binary.LittleEndian, &e)
// put EXPORT Address Table
for _, s := range dexport {
out.Write32(uint32(ldr.SymValue(s) - PEBASE))
}
// put EXPORT Name Pointer Table
v := int(e.Name + uint32(len(*flagOutfile)) + 1)
for _, s := range dexport {
out.Write32(uint32(v))
v += len(ldr.SymExtname(s)) + 1
}
// put EXPORT Ordinal Table
for i := 0; i < nexport; i++ {
out.Write16(uint16(i))
}
// put Names
out.WriteStringN(*flagOutfile, len(*flagOutfile)+1)
for _, s := range dexport {
name := ldr.SymExtname(s)
out.WriteStringN(name, len(name)+1)
}
sect.pad(out, uint32(size))
}
// peBaseRelocEntry represents a single relocation entry.
type peBaseRelocEntry struct {
typeOff uint16
}
// peBaseRelocBlock represents a Base Relocation Block. A block
// is a collection of relocation entries in a page, where each
// entry describes a single relocation.
// The block page RVA (Relative Virtual Address) is the index
// into peBaseRelocTable.blocks.
type peBaseRelocBlock struct {
entries []peBaseRelocEntry
}
// pePages is a type used to store the list of pages for which there
// are base relocation blocks. This is defined as a type so that
// it can be sorted.
type pePages []uint32
func (p pePages) Len() int { return len(p) }
func (p pePages) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
func (p pePages) Less(i, j int) bool { return p[i] < p[j] }
// A PE base relocation table is a list of blocks, where each block
// contains relocation information for a single page. The blocks
// must be emitted in order of page virtual address.
// See https://docs.microsoft.com/en-us/windows/desktop/debug/pe-format#the-reloc-section-image-only
type peBaseRelocTable struct {
blocks map[uint32]peBaseRelocBlock
// pePages is a list of keys into blocks map.
// It is stored separately for ease of sorting.
pages pePages
}
func (rt *peBaseRelocTable) init(ctxt *Link) {
rt.blocks = make(map[uint32]peBaseRelocBlock)
}
func (rt *peBaseRelocTable) addentry(ldr *loader.Loader, s loader.Sym, r *loader.Reloc) {
// pageSize is the size in bytes of a page
// described by a base relocation block.
const pageSize = 0x1000
const pageMask = pageSize - 1
addr := ldr.SymValue(s) + int64(r.Off()) - int64(PEBASE)
page := uint32(addr &^ pageMask)
off := uint32(addr & pageMask)
b, ok := rt.blocks[page]
if !ok {
rt.pages = append(rt.pages, page)
}
e := peBaseRelocEntry{
typeOff: uint16(off & 0xFFF),
}
// Set entry type
switch r.Siz() {
default:
Exitf("unsupported relocation size %d\n", r.Siz)
case 4:
e.typeOff |= uint16(IMAGE_REL_BASED_HIGHLOW << 12)
case 8:
e.typeOff |= uint16(IMAGE_REL_BASED_DIR64 << 12)
}
b.entries = append(b.entries, e)
rt.blocks[page] = b
}
func (rt *peBaseRelocTable) write(ctxt *Link) {
out := ctxt.Out
// sort the pages array
sort.Sort(rt.pages)
for _, p := range rt.pages {
b := rt.blocks[p]
const sizeOfPEbaseRelocBlock = 8 // 2 * sizeof(uint32)
blockSize := uint32(sizeOfPEbaseRelocBlock + len(b.entries)*2)
out.Write32(p)
out.Write32(blockSize)
for _, e := range b.entries {
out.Write16(e.typeOff)
}
}
}
func addPEBaseRelocSym(ldr *loader.Loader, s loader.Sym, rt *peBaseRelocTable) {
relocs := ldr.Relocs(s)
for ri := 0; ri < relocs.Count(); ri++ {
r := relocs.At(ri)
if r.Type() >= objabi.ElfRelocOffset {
continue
}
if r.Siz() == 0 { // informational relocation
continue
}
if r.Type() == objabi.R_DWARFFILEREF {
continue
}
rs := r.Sym()
rs = ldr.ResolveABIAlias(rs)
if rs == 0 {
continue
}
if !ldr.AttrReachable(s) {
continue
}
switch r.Type() {
default:
case objabi.R_ADDR:
rt.addentry(ldr, s, &r)
}
}
}
func needPEBaseReloc(ctxt *Link) bool {
// Non-PIE x86 binaries don't need the base relocation table.
// Everyone else does.
if (ctxt.Arch.Family == sys.I386 || ctxt.Arch.Family == sys.AMD64) && ctxt.BuildMode != BuildModePIE {
return false
}
return true
}
func addPEBaseReloc(ctxt *Link) {
if !needPEBaseReloc(ctxt) {
return
}
var rt peBaseRelocTable
rt.init(ctxt)
// Get relocation information
ldr := ctxt.loader
for _, s := range ctxt.Textp {
addPEBaseRelocSym(ldr, s, &rt)
}
for _, s := range ctxt.datap {
addPEBaseRelocSym(ldr, s, &rt)
}
// Write relocation information
startoff := ctxt.Out.Offset()
rt.write(ctxt)
size := ctxt.Out.Offset() - startoff
// Add a PE section and pad it at the end
rsect := pefile.addSection(".reloc", int(size), int(size))
rsect.characteristics = IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_DISCARDABLE
rsect.checkOffset(startoff)
rsect.pad(ctxt.Out, uint32(size))
pefile.dataDirectory[pe.IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress = rsect.virtualAddress
pefile.dataDirectory[pe.IMAGE_DIRECTORY_ENTRY_BASERELOC].Size = rsect.virtualSize
}
func (ctxt *Link) dope() {
initdynimport(ctxt)
initdynexport(ctxt)
}
func setpersrc(ctxt *Link, syms []loader.Sym) {
if len(rsrcsyms) != 0 {
Errorf(nil, "too many .rsrc sections")
}
rsrcsyms = syms
}
func addpersrc(ctxt *Link) {
if len(rsrcsyms) == 0 {
return
}
var size int64
for _, rsrcsym := range rsrcsyms {
size += ctxt.loader.SymSize(rsrcsym)
}
h := pefile.addSection(".rsrc", int(size), int(size))
h.characteristics = IMAGE_SCN_MEM_READ | IMAGE_SCN_CNT_INITIALIZED_DATA
h.checkOffset(ctxt.Out.Offset())
for _, rsrcsym := range rsrcsyms {
// A split resource happens when the actual resource data and its relocations are
// split across multiple sections, denoted by a $01 or $02 at the end of the .rsrc
// section name.
splitResources := strings.Contains(ctxt.loader.SymName(rsrcsym), ".rsrc$")
relocs := ctxt.loader.Relocs(rsrcsym)
data := ctxt.loader.Data(rsrcsym)
for ri := 0; ri < relocs.Count(); ri++ {
r := relocs.At(ri)
p := data[r.Off():]
val := uint32(int64(h.virtualAddress) + r.Add())
if splitResources {
// If we're a split resource section, and that section has relocation
// symbols, then the data that it points to doesn't actually begin at
// the virtual address listed in this current section, but rather
// begins at the section immediately after this one. So, in order to
// calculate the proper virtual address of the data it's pointing to,
// we have to add the length of this section to the virtual address.
// This works because .rsrc sections are divided into two (but not more)
// of these sections.
val += uint32(len(data))
}
binary.LittleEndian.PutUint32(p, val)
}
ctxt.Out.Write(data)
}
h.pad(ctxt.Out, uint32(size))
// update data directory
pefile.dataDirectory[pe.IMAGE_DIRECTORY_ENTRY_RESOURCE].VirtualAddress = h.virtualAddress
pefile.dataDirectory[pe.IMAGE_DIRECTORY_ENTRY_RESOURCE].Size = h.virtualSize
}
func asmbPe(ctxt *Link) {
t := pefile.addSection(".text", int(Segtext.Length), int(Segtext.Length))
t.characteristics = IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_READ
if ctxt.LinkMode == LinkExternal {
// some data symbols (e.g. masks) end up in the .text section, and they normally
// expect larger alignment requirement than the default text section alignment.
t.characteristics |= IMAGE_SCN_ALIGN_32BYTES
}
t.checkSegment(&Segtext)
pefile.textSect = t
ro := pefile.addSection(".rdata", int(Segrodata.Length), int(Segrodata.Length))
ro.characteristics = IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ
if ctxt.LinkMode == LinkExternal {
// some data symbols (e.g. masks) end up in the .rdata section, and they normally
// expect larger alignment requirement than the default text section alignment.
ro.characteristics |= IMAGE_SCN_ALIGN_32BYTES
}
ro.checkSegment(&Segrodata)
pefile.rdataSect = ro
var d *peSection
if ctxt.LinkMode != LinkExternal {
d = pefile.addSection(".data", int(Segdata.Length), int(Segdata.Filelen))
d.characteristics = IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE
d.checkSegment(&Segdata)
pefile.dataSect = d
} else {
d = pefile.addSection(".data", int(Segdata.Filelen), int(Segdata.Filelen))
d.characteristics = IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_ALIGN_32BYTES
d.checkSegment(&Segdata)
pefile.dataSect = d
b := pefile.addSection(".bss", int(Segdata.Length-Segdata.Filelen), 0)
b.characteristics = IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_ALIGN_32BYTES
b.pointerToRawData = 0
pefile.bssSect = b
}
pefile.addDWARF()
if ctxt.LinkMode == LinkExternal {
pefile.ctorsSect = pefile.addInitArray(ctxt)
}
ctxt.Out.SeekSet(int64(pefile.nextFileOffset))
if ctxt.LinkMode != LinkExternal {
addimports(ctxt, d)
addexports(ctxt)
addPEBaseReloc(ctxt)
}
pefile.writeSymbolTableAndStringTable(ctxt)
addpersrc(ctxt)
if ctxt.LinkMode == LinkExternal {
pefile.emitRelocations(ctxt)
}
pewrite(ctxt)
}
Mini Shell