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go / go / 3c85e995efd0c2adf8578ed27565ad3b427f1a43 / . / src / cmd / link / internal / ld / elf.go
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// 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.
package ld
import (
"cmd/internal/objabi"
"cmd/internal/sys"
"cmd/link/internal/loader"
"cmd/link/internal/sym"
"crypto/sha1"
"encoding/binary"
"encoding/hex"
"fmt"
"path/filepath"
"sort"
"strings"
)
/*
* Derived from:
* $FreeBSD: src/sys/sys/elf32.h,v 1.8.14.1 2005/12/30 22:13:58 marcel Exp $
* $FreeBSD: src/sys/sys/elf64.h,v 1.10.14.1 2005/12/30 22:13:58 marcel Exp $
* $FreeBSD: src/sys/sys/elf_common.h,v 1.15.8.1 2005/12/30 22:13:58 marcel Exp $
* $FreeBSD: src/sys/alpha/include/elf.h,v 1.14 2003/09/25 01:10:22 peter Exp $
* $FreeBSD: src/sys/amd64/include/elf.h,v 1.18 2004/08/03 08:21:48 dfr Exp $
* $FreeBSD: src/sys/arm/include/elf.h,v 1.5.2.1 2006/06/30 21:42:52 cognet Exp $
* $FreeBSD: src/sys/i386/include/elf.h,v 1.16 2004/08/02 19:12:17 dfr Exp $
* $FreeBSD: src/sys/powerpc/include/elf.h,v 1.7 2004/11/02 09:47:01 ssouhlal Exp $
* $FreeBSD: src/sys/sparc64/include/elf.h,v 1.12 2003/09/25 01:10:26 peter Exp $
*
* Copyright (c) 1996-1998 John D. Polstra. All rights reserved.
* Copyright (c) 2001 David E. O'Brien
* Portions Copyright 2009 The Go Authors. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
/*
* ELF definitions that are independent of architecture or word size.
*/
/*
* Note header. The ".note" section contains an array of notes. Each
* begins with this header, aligned to a word boundary. Immediately
* following the note header is n_namesz bytes of name, padded to the
* next word boundary. Then comes n_descsz bytes of descriptor, again
* padded to a word boundary. The values of n_namesz and n_descsz do
* not include the padding.
*/
type elfNote struct {
nNamesz uint32
nDescsz uint32
nType uint32
}
const (
EI_MAG0 = 0
EI_MAG1 = 1
EI_MAG2 = 2
EI_MAG3 = 3
EI_CLASS = 4
EI_DATA = 5
EI_VERSION = 6
EI_OSABI = 7
EI_ABIVERSION = 8
OLD_EI_BRAND = 8
EI_PAD = 9
EI_NIDENT = 16
ELFMAG0 = 0x7f
ELFMAG1 = 'E'
ELFMAG2 = 'L'
ELFMAG3 = 'F'
SELFMAG = 4
EV_NONE = 0
EV_CURRENT = 1
ELFCLASSNONE = 0
ELFCLASS32 = 1
ELFCLASS64 = 2
ELFDATANONE = 0
ELFDATA2LSB = 1
ELFDATA2MSB = 2
ELFOSABI_NONE = 0
ELFOSABI_HPUX = 1
ELFOSABI_NETBSD = 2
ELFOSABI_LINUX = 3
ELFOSABI_HURD = 4
ELFOSABI_86OPEN = 5
ELFOSABI_SOLARIS = 6
ELFOSABI_AIX = 7
ELFOSABI_IRIX = 8
ELFOSABI_FREEBSD = 9
ELFOSABI_TRU64 = 10
ELFOSABI_MODESTO = 11
ELFOSABI_OPENBSD = 12
ELFOSABI_OPENVMS = 13
ELFOSABI_NSK = 14
ELFOSABI_ARM = 97
ELFOSABI_STANDALONE = 255
ELFOSABI_SYSV = ELFOSABI_NONE
ELFOSABI_MONTEREY = ELFOSABI_AIX
ET_NONE = 0
ET_REL = 1
ET_EXEC = 2
ET_DYN = 3
ET_CORE = 4
ET_LOOS = 0xfe00
ET_HIOS = 0xfeff
ET_LOPROC = 0xff00
ET_HIPROC = 0xffff
EM_NONE = 0
EM_M32 = 1
EM_SPARC = 2
EM_386 = 3
EM_68K = 4
EM_88K = 5
EM_860 = 7
EM_MIPS = 8
EM_S370 = 9
EM_MIPS_RS3_LE = 10
EM_PARISC = 15
EM_VPP500 = 17
EM_SPARC32PLUS = 18
EM_960 = 19
EM_PPC = 20
EM_PPC64 = 21
EM_S390 = 22
EM_V800 = 36
EM_FR20 = 37
EM_RH32 = 38
EM_RCE = 39
EM_ARM = 40
EM_SH = 42
EM_SPARCV9 = 43
EM_TRICORE = 44
EM_ARC = 45
EM_H8_300 = 46
EM_H8_300H = 47
EM_H8S = 48
EM_H8_500 = 49
EM_IA_64 = 50
EM_MIPS_X = 51
EM_COLDFIRE = 52
EM_68HC12 = 53
EM_MMA = 54
EM_PCP = 55
EM_NCPU = 56
EM_NDR1 = 57
EM_STARCORE = 58
EM_ME16 = 59
EM_ST100 = 60
EM_TINYJ = 61
EM_X86_64 = 62
EM_AARCH64 = 183
EM_486 = 6
EM_MIPS_RS4_BE = 10
EM_ALPHA_STD = 41
EM_ALPHA = 0x9026
EM_RISCV = 243
SHN_UNDEF = 0
SHN_LORESERVE = 0xff00
SHN_LOPROC = 0xff00
SHN_HIPROC = 0xff1f
SHN_LOOS = 0xff20
SHN_HIOS = 0xff3f
SHN_ABS = 0xfff1
SHN_COMMON = 0xfff2
SHN_XINDEX = 0xffff
SHN_HIRESERVE = 0xffff
SHT_NULL = 0
SHT_PROGBITS = 1
SHT_SYMTAB = 2
SHT_STRTAB = 3
SHT_RELA = 4
SHT_HASH = 5
SHT_DYNAMIC = 6
SHT_NOTE = 7
SHT_NOBITS = 8
SHT_REL = 9
SHT_SHLIB = 10
SHT_DYNSYM = 11
SHT_INIT_ARRAY = 14
SHT_FINI_ARRAY = 15
SHT_PREINIT_ARRAY = 16
SHT_GROUP = 17
SHT_SYMTAB_SHNDX = 18
SHT_LOOS = 0x60000000
SHT_HIOS = 0x6fffffff
SHT_GNU_VERDEF = 0x6ffffffd
SHT_GNU_VERNEED = 0x6ffffffe
SHT_GNU_VERSYM = 0x6fffffff
SHT_LOPROC = 0x70000000
SHT_ARM_ATTRIBUTES = 0x70000003
SHT_HIPROC = 0x7fffffff
SHT_LOUSER = 0x80000000
SHT_HIUSER = 0xffffffff
SHF_WRITE = 0x1
SHF_ALLOC = 0x2
SHF_EXECINSTR = 0x4
SHF_MERGE = 0x10
SHF_STRINGS = 0x20
SHF_INFO_LINK = 0x40
SHF_LINK_ORDER = 0x80
SHF_OS_NONCONFORMING = 0x100
SHF_GROUP = 0x200
SHF_TLS = 0x400
SHF_MASKOS = 0x0ff00000
SHF_MASKPROC = 0xf0000000
PT_NULL = 0
PT_LOAD = 1
PT_DYNAMIC = 2
PT_INTERP = 3
PT_NOTE = 4
PT_SHLIB = 5
PT_PHDR = 6
PT_TLS = 7
PT_LOOS = 0x60000000
PT_HIOS = 0x6fffffff
PT_LOPROC = 0x70000000
PT_HIPROC = 0x7fffffff
PT_GNU_STACK = 0x6474e551
PT_GNU_RELRO = 0x6474e552
PT_PAX_FLAGS = 0x65041580
PT_SUNWSTACK = 0x6ffffffb
PF_X = 0x1
PF_W = 0x2
PF_R = 0x4
PF_MASKOS = 0x0ff00000
PF_MASKPROC = 0xf0000000
DT_NULL = 0
DT_NEEDED = 1
DT_PLTRELSZ = 2
DT_PLTGOT = 3
DT_HASH = 4
DT_STRTAB = 5
DT_SYMTAB = 6
DT_RELA = 7
DT_RELASZ = 8
DT_RELAENT = 9
DT_STRSZ = 10
DT_SYMENT = 11
DT_INIT = 12
DT_FINI = 13
DT_SONAME = 14
DT_RPATH = 15
DT_SYMBOLIC = 16
DT_REL = 17
DT_RELSZ = 18
DT_RELENT = 19
DT_PLTREL = 20
DT_DEBUG = 21
DT_TEXTREL = 22
DT_JMPREL = 23
DT_BIND_NOW = 24
DT_INIT_ARRAY = 25
DT_FINI_ARRAY = 26
DT_INIT_ARRAYSZ = 27
DT_FINI_ARRAYSZ = 28
DT_RUNPATH = 29
DT_FLAGS = 30
DT_ENCODING = 32
DT_PREINIT_ARRAY = 32
DT_PREINIT_ARRAYSZ = 33
DT_LOOS = 0x6000000d
DT_HIOS = 0x6ffff000
DT_LOPROC = 0x70000000
DT_HIPROC = 0x7fffffff
DT_VERNEED = 0x6ffffffe
DT_VERNEEDNUM = 0x6fffffff
DT_VERSYM = 0x6ffffff0
DT_PPC64_GLINK = DT_LOPROC + 0
DT_PPC64_OPT = DT_LOPROC + 3
DF_ORIGIN = 0x0001
DF_SYMBOLIC = 0x0002
DF_TEXTREL = 0x0004
DF_BIND_NOW = 0x0008
DF_STATIC_TLS = 0x0010
NT_PRSTATUS = 1
NT_FPREGSET = 2
NT_PRPSINFO = 3
STB_LOCAL = 0
STB_GLOBAL = 1
STB_WEAK = 2
STB_LOOS = 10
STB_HIOS = 12
STB_LOPROC = 13
STB_HIPROC = 15
STT_NOTYPE = 0
STT_OBJECT = 1
STT_FUNC = 2
STT_SECTION = 3
STT_FILE = 4
STT_COMMON = 5
STT_TLS = 6
STT_LOOS = 10
STT_HIOS = 12
STT_LOPROC = 13
STT_HIPROC = 15
STV_DEFAULT = 0x0
STV_INTERNAL = 0x1
STV_HIDDEN = 0x2
STV_PROTECTED = 0x3
STN_UNDEF = 0
)
/* For accessing the fields of r_info. */
/* For constructing r_info from field values. */
/*
* Relocation types.
*/
const (
ARM_MAGIC_TRAMP_NUMBER = 0x5c000003
)
/*
* Symbol table entries.
*/
/* For accessing the fields of st_info. */
/* For constructing st_info from field values. */
/* For accessing the fields of st_other. */
/*
* ELF header.
*/
type ElfEhdr struct {
ident [EI_NIDENT]uint8
type_ uint16
machine uint16
version uint32
entry uint64
phoff uint64
shoff uint64
flags uint32
ehsize uint16
phentsize uint16
phnum uint16
shentsize uint16
shnum uint16
shstrndx uint16
}
/*
* Section header.
*/
type ElfShdr struct {
name uint32
type_ uint32
flags uint64
addr uint64
off uint64
size uint64
link uint32
info uint32
addralign uint64
entsize uint64
shnum int
}
/*
* Program header.
*/
type ElfPhdr struct {
type_ uint32
flags uint32
off uint64
vaddr uint64
paddr uint64
filesz uint64
memsz uint64
align uint64
}
/* For accessing the fields of r_info. */
/* For constructing r_info from field values. */
/*
* Symbol table entries.
*/
/* For accessing the fields of st_info. */
/* For constructing st_info from field values. */
/* For accessing the fields of st_other. */
/*
* Go linker interface
*/
const (
ELF64HDRSIZE = 64
ELF64PHDRSIZE = 56
ELF64SHDRSIZE = 64
ELF64RELSIZE = 16
ELF64RELASIZE = 24
ELF64SYMSIZE = 24
ELF32HDRSIZE = 52
ELF32PHDRSIZE = 32
ELF32SHDRSIZE = 40
ELF32SYMSIZE = 16
ELF32RELSIZE = 8
)
/*
* The interface uses the 64-bit structures always,
* to avoid code duplication. The writers know how to
* marshal a 32-bit representation from the 64-bit structure.
*/
var Elfstrdat []byte
/*
* Total amount of space to reserve at the start of the file
* for Header, PHeaders, SHeaders, and interp.
* May waste some.
* On FreeBSD, cannot be larger than a page.
*/
const (
ELFRESERVE = 4096
)
/*
* We use the 64-bit data structures on both 32- and 64-bit machines
* in order to write the code just once. The 64-bit data structure is
* written in the 32-bit format on the 32-bit machines.
*/
const (
NSECT = 400
)
var (
Nelfsym = 1
elf64 bool
// Either ".rel" or ".rela" depending on which type of relocation the
// target platform uses.
elfRelType string
ehdr ElfEhdr
phdr [NSECT]*ElfPhdr
shdr [NSECT]*ElfShdr
interp string
)
type Elfstring struct {
s string
off int
}
var elfstr [100]Elfstring
var nelfstr int
var buildinfo []byte
/*
Initialize the global variable that describes the ELF header. It will be updated as
we write section and prog headers.
*/
func Elfinit(ctxt *Link) {
ctxt.IsELF = true
if ctxt.Arch.InFamily(sys.AMD64, sys.ARM64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X) {
elfRelType = ".rela"
} else {
elfRelType = ".rel"
}
switch ctxt.Arch.Family {
// 64-bit architectures
case sys.PPC64, sys.S390X:
if ctxt.Arch.ByteOrder == binary.BigEndian {
ehdr.flags = 1 /* Version 1 ABI */
} else {
ehdr.flags = 2 /* Version 2 ABI */
}
fallthrough
case sys.AMD64, sys.ARM64, sys.MIPS64, sys.RISCV64:
if ctxt.Arch.Family == sys.MIPS64 {
ehdr.flags = 0x20000004 /* MIPS 3 CPIC */
}
elf64 = true
ehdr.phoff = ELF64HDRSIZE /* Must be ELF64HDRSIZE: first PHdr must follow ELF header */
ehdr.shoff = ELF64HDRSIZE /* Will move as we add PHeaders */
ehdr.ehsize = ELF64HDRSIZE /* Must be ELF64HDRSIZE */
ehdr.phentsize = ELF64PHDRSIZE /* Must be ELF64PHDRSIZE */
ehdr.shentsize = ELF64SHDRSIZE /* Must be ELF64SHDRSIZE */
// 32-bit architectures
case sys.ARM, sys.MIPS:
if ctxt.Arch.Family == sys.ARM {
// we use EABI on linux/arm, freebsd/arm, netbsd/arm.
if ctxt.HeadType == objabi.Hlinux || ctxt.HeadType == objabi.Hfreebsd || ctxt.HeadType == objabi.Hnetbsd {
// We set a value here that makes no indication of which
// float ABI the object uses, because this is information
// used by the dynamic linker to compare executables and
// shared libraries -- so it only matters for cgo calls, and
// the information properly comes from the object files
// produced by the host C compiler. parseArmAttributes in
// ldelf.go reads that information and updates this field as
// appropriate.
ehdr.flags = 0x5000002 // has entry point, Version5 EABI
}
} else if ctxt.Arch.Family == sys.MIPS {
ehdr.flags = 0x50001004 /* MIPS 32 CPIC O32*/
}
fallthrough
default:
ehdr.phoff = ELF32HDRSIZE
/* Must be ELF32HDRSIZE: first PHdr must follow ELF header */
ehdr.shoff = ELF32HDRSIZE /* Will move as we add PHeaders */
ehdr.ehsize = ELF32HDRSIZE /* Must be ELF32HDRSIZE */
ehdr.phentsize = ELF32PHDRSIZE /* Must be ELF32PHDRSIZE */
ehdr.shentsize = ELF32SHDRSIZE /* Must be ELF32SHDRSIZE */
}
}
// Make sure PT_LOAD is aligned properly and
// that there is no gap,
// correct ELF loaders will do this implicitly,
// but buggy ELF loaders like the one in some
// versions of QEMU and UPX won't.
func fixElfPhdr(e *ElfPhdr) {
frag := int(e.vaddr & (e.align - 1))
e.off -= uint64(frag)
e.vaddr -= uint64(frag)
e.paddr -= uint64(frag)
e.filesz += uint64(frag)
e.memsz += uint64(frag)
}
func elf64phdr(out *OutBuf, e *ElfPhdr) {
if e.type_ == PT_LOAD {
fixElfPhdr(e)
}
out.Write32(e.type_)
out.Write32(e.flags)
out.Write64(e.off)
out.Write64(e.vaddr)
out.Write64(e.paddr)
out.Write64(e.filesz)
out.Write64(e.memsz)
out.Write64(e.align)
}
func elf32phdr(out *OutBuf, e *ElfPhdr) {
if e.type_ == PT_LOAD {
fixElfPhdr(e)
}
out.Write32(e.type_)
out.Write32(uint32(e.off))
out.Write32(uint32(e.vaddr))
out.Write32(uint32(e.paddr))
out.Write32(uint32(e.filesz))
out.Write32(uint32(e.memsz))
out.Write32(e.flags)
out.Write32(uint32(e.align))
}
func elf64shdr(out *OutBuf, e *ElfShdr) {
out.Write32(e.name)
out.Write32(e.type_)
out.Write64(e.flags)
out.Write64(e.addr)
out.Write64(e.off)
out.Write64(e.size)
out.Write32(e.link)
out.Write32(e.info)
out.Write64(e.addralign)
out.Write64(e.entsize)
}
func elf32shdr(out *OutBuf, e *ElfShdr) {
out.Write32(e.name)
out.Write32(e.type_)
out.Write32(uint32(e.flags))
out.Write32(uint32(e.addr))
out.Write32(uint32(e.off))
out.Write32(uint32(e.size))
out.Write32(e.link)
out.Write32(e.info)
out.Write32(uint32(e.addralign))
out.Write32(uint32(e.entsize))
}
func elfwriteshdrs(out *OutBuf) uint32 {
if elf64 {
for i := 0; i < int(ehdr.shnum); i++ {
elf64shdr(out, shdr[i])
}
return uint32(ehdr.shnum) * ELF64SHDRSIZE
}
for i := 0; i < int(ehdr.shnum); i++ {
elf32shdr(out, shdr[i])
}
return uint32(ehdr.shnum) * ELF32SHDRSIZE
}
func elfsetstring(ctxt *Link, s loader.Sym, str string, off int) {
if nelfstr >= len(elfstr) {
ctxt.Errorf(s, "too many elf strings")
errorexit()
}
elfstr[nelfstr].s = str
elfstr[nelfstr].off = off
nelfstr++
}
func elfwritephdrs(out *OutBuf) uint32 {
if elf64 {
for i := 0; i < int(ehdr.phnum); i++ {
elf64phdr(out, phdr[i])
}
return uint32(ehdr.phnum) * ELF64PHDRSIZE
}
for i := 0; i < int(ehdr.phnum); i++ {
elf32phdr(out, phdr[i])
}
return uint32(ehdr.phnum) * ELF32PHDRSIZE
}
func newElfPhdr() *ElfPhdr {
e := new(ElfPhdr)
if ehdr.phnum >= NSECT {
Errorf(nil, "too many phdrs")
} else {
phdr[ehdr.phnum] = e
ehdr.phnum++
}
if elf64 {
ehdr.shoff += ELF64PHDRSIZE
} else {
ehdr.shoff += ELF32PHDRSIZE
}
return e
}
func newElfShdr(name int64) *ElfShdr {
e := new(ElfShdr)
e.name = uint32(name)
e.shnum = int(ehdr.shnum)
if ehdr.shnum >= NSECT {
Errorf(nil, "too many shdrs")
} else {
shdr[ehdr.shnum] = e
ehdr.shnum++
}
return e
}
func getElfEhdr() *ElfEhdr {
return &ehdr
}
func elf64writehdr(out *OutBuf) uint32 {
out.Write(ehdr.ident[:])
out.Write16(ehdr.type_)
out.Write16(ehdr.machine)
out.Write32(ehdr.version)
out.Write64(ehdr.entry)
out.Write64(ehdr.phoff)
out.Write64(ehdr.shoff)
out.Write32(ehdr.flags)
out.Write16(ehdr.ehsize)
out.Write16(ehdr.phentsize)
out.Write16(ehdr.phnum)
out.Write16(ehdr.shentsize)
out.Write16(ehdr.shnum)
out.Write16(ehdr.shstrndx)
return ELF64HDRSIZE
}
func elf32writehdr(out *OutBuf) uint32 {
out.Write(ehdr.ident[:])
out.Write16(ehdr.type_)
out.Write16(ehdr.machine)
out.Write32(ehdr.version)
out.Write32(uint32(ehdr.entry))
out.Write32(uint32(ehdr.phoff))
out.Write32(uint32(ehdr.shoff))
out.Write32(ehdr.flags)
out.Write16(ehdr.ehsize)
out.Write16(ehdr.phentsize)
out.Write16(ehdr.phnum)
out.Write16(ehdr.shentsize)
out.Write16(ehdr.shnum)
out.Write16(ehdr.shstrndx)
return ELF32HDRSIZE
}
func elfwritehdr(out *OutBuf) uint32 {
if elf64 {
return elf64writehdr(out)
}
return elf32writehdr(out)
}
/* Taken directly from the definition document for ELF64 */
func elfhash(name string) uint32 {
var h uint32
for i := 0; i < len(name); i++ {
h = (h << 4) + uint32(name[i])
if g := h & 0xf0000000; g != 0 {
h ^= g >> 24
}
h &= 0x0fffffff
}
return h
}
func elfWriteDynEntSym(ctxt *Link, s *loader.SymbolBuilder, tag int, t loader.Sym) {
Elfwritedynentsymplus(ctxt, s, tag, t, 0)
}
func Elfwritedynent(arch *sys.Arch, s *loader.SymbolBuilder, tag int, val uint64) {
if elf64 {
s.AddUint64(arch, uint64(tag))
s.AddUint64(arch, val)
} else {
s.AddUint32(arch, uint32(tag))
s.AddUint32(arch, uint32(val))
}
}
func elfwritedynentsym(ctxt *Link, s *loader.SymbolBuilder, tag int, t loader.Sym) {
Elfwritedynentsymplus(ctxt, s, tag, t, 0)
}
func Elfwritedynentsymplus(ctxt *Link, s *loader.SymbolBuilder, tag int, t loader.Sym, add int64) {
if elf64 {
s.AddUint64(ctxt.Arch, uint64(tag))
} else {
s.AddUint32(ctxt.Arch, uint32(tag))
}
s.AddAddrPlus(ctxt.Arch, t, add)
}
func elfwritedynentsymsize(ctxt *Link, s *loader.SymbolBuilder, tag int, t loader.Sym) {
if elf64 {
s.AddUint64(ctxt.Arch, uint64(tag))
} else {
s.AddUint32(ctxt.Arch, uint32(tag))
}
s.AddSize(ctxt.Arch, t)
}
func elfinterp(sh *ElfShdr, startva uint64, resoff uint64, p string) int {
interp = p
n := len(interp) + 1
sh.addr = startva + resoff - uint64(n)
sh.off = resoff - uint64(n)
sh.size = uint64(n)
return n
}
func elfwriteinterp(out *OutBuf) int {
sh := elfshname(".interp")
out.SeekSet(int64(sh.off))
out.WriteString(interp)
out.Write8(0)
return int(sh.size)
}
func elfnote(sh *ElfShdr, startva uint64, resoff uint64, sz int) int {
n := 3*4 + uint64(sz) + resoff%4
sh.type_ = SHT_NOTE
sh.flags = SHF_ALLOC
sh.addralign = 4
sh.addr = startva + resoff - n
sh.off = resoff - n
sh.size = n - resoff%4
return int(n)
}
func elfwritenotehdr(out *OutBuf, str string, namesz uint32, descsz uint32, tag uint32) *ElfShdr {
sh := elfshname(str)
// Write Elf_Note header.
out.SeekSet(int64(sh.off))
out.Write32(namesz)
out.Write32(descsz)
out.Write32(tag)
return sh
}
// NetBSD Signature (as per sys/exec_elf.h)
const (
ELF_NOTE_NETBSD_NAMESZ = 7
ELF_NOTE_NETBSD_DESCSZ = 4
ELF_NOTE_NETBSD_TAG = 1
ELF_NOTE_NETBSD_VERSION = 700000000 /* NetBSD 7.0 */
)
var ELF_NOTE_NETBSD_NAME = []byte("NetBSD\x00")
func elfnetbsdsig(sh *ElfShdr, startva uint64, resoff uint64) int {
n := int(Rnd(ELF_NOTE_NETBSD_NAMESZ, 4) + Rnd(ELF_NOTE_NETBSD_DESCSZ, 4))
return elfnote(sh, startva, resoff, n)
}
func elfwritenetbsdsig(out *OutBuf) int {
// Write Elf_Note header.
sh := elfwritenotehdr(out, ".note.netbsd.ident", ELF_NOTE_NETBSD_NAMESZ, ELF_NOTE_NETBSD_DESCSZ, ELF_NOTE_NETBSD_TAG)
if sh == nil {
return 0
}
// Followed by NetBSD string and version.
out.Write(ELF_NOTE_NETBSD_NAME)
out.Write8(0)
out.Write32(ELF_NOTE_NETBSD_VERSION)
return int(sh.size)
}
// The race detector can't handle ASLR (address space layout randomization).
// ASLR is on by default for NetBSD, so we turn the ASLR off explicitly
// using a magic elf Note when building race binaries.
func elfnetbsdpax(sh *ElfShdr, startva uint64, resoff uint64) int {
n := int(Rnd(4, 4) + Rnd(4, 4))
return elfnote(sh, startva, resoff, n)
}
func elfwritenetbsdpax(out *OutBuf) int {
sh := elfwritenotehdr(out, ".note.netbsd.pax", 4 /* length of PaX\x00 */, 4 /* length of flags */, 0x03 /* PaX type */)
if sh == nil {
return 0
}
out.Write([]byte("PaX\x00"))
out.Write32(0x20) // 0x20 = Force disable ASLR
return int(sh.size)
}
// OpenBSD Signature
const (
ELF_NOTE_OPENBSD_NAMESZ = 8
ELF_NOTE_OPENBSD_DESCSZ = 4
ELF_NOTE_OPENBSD_TAG = 1
ELF_NOTE_OPENBSD_VERSION = 0
)
var ELF_NOTE_OPENBSD_NAME = []byte("OpenBSD\x00")
func elfopenbsdsig(sh *ElfShdr, startva uint64, resoff uint64) int {
n := ELF_NOTE_OPENBSD_NAMESZ + ELF_NOTE_OPENBSD_DESCSZ
return elfnote(sh, startva, resoff, n)
}
func elfwriteopenbsdsig(out *OutBuf) int {
// Write Elf_Note header.
sh := elfwritenotehdr(out, ".note.openbsd.ident", ELF_NOTE_OPENBSD_NAMESZ, ELF_NOTE_OPENBSD_DESCSZ, ELF_NOTE_OPENBSD_TAG)
if sh == nil {
return 0
}
// Followed by OpenBSD string and version.
out.Write(ELF_NOTE_OPENBSD_NAME)
out.Write32(ELF_NOTE_OPENBSD_VERSION)
return int(sh.size)
}
func addbuildinfo(val string) {
if !strings.HasPrefix(val, "0x") {
Exitf("-B argument must start with 0x: %s", val)
}
ov := val
val = val[2:]
const maxLen = 32
if hex.DecodedLen(len(val)) > maxLen {
Exitf("-B option too long (max %d digits): %s", maxLen, ov)
}
b, err := hex.DecodeString(val)
if err != nil {
if err == hex.ErrLength {
Exitf("-B argument must have even number of digits: %s", ov)
}
if inv, ok := err.(hex.InvalidByteError); ok {
Exitf("-B argument contains invalid hex digit %c: %s", byte(inv), ov)
}
Exitf("-B argument contains invalid hex: %s", ov)
}
buildinfo = b
}
// Build info note
const (
ELF_NOTE_BUILDINFO_NAMESZ = 4
ELF_NOTE_BUILDINFO_TAG = 3
)
var ELF_NOTE_BUILDINFO_NAME = []byte("GNU\x00")
func elfbuildinfo(sh *ElfShdr, startva uint64, resoff uint64) int {
n := int(ELF_NOTE_BUILDINFO_NAMESZ + Rnd(int64(len(buildinfo)), 4))
return elfnote(sh, startva, resoff, n)
}
func elfgobuildid(sh *ElfShdr, startva uint64, resoff uint64) int {
n := len(ELF_NOTE_GO_NAME) + int(Rnd(int64(len(*flagBuildid)), 4))
return elfnote(sh, startva, resoff, n)
}
func elfwritebuildinfo(out *OutBuf) int {
sh := elfwritenotehdr(out, ".note.gnu.build-id", ELF_NOTE_BUILDINFO_NAMESZ, uint32(len(buildinfo)), ELF_NOTE_BUILDINFO_TAG)
if sh == nil {
return 0
}
out.Write(ELF_NOTE_BUILDINFO_NAME)
out.Write(buildinfo)
var zero = make([]byte, 4)
out.Write(zero[:int(Rnd(int64(len(buildinfo)), 4)-int64(len(buildinfo)))])
return int(sh.size)
}
func elfwritegobuildid(out *OutBuf) int {
sh := elfwritenotehdr(out, ".note.go.buildid", uint32(len(ELF_NOTE_GO_NAME)), uint32(len(*flagBuildid)), ELF_NOTE_GOBUILDID_TAG)
if sh == nil {
return 0
}
out.Write(ELF_NOTE_GO_NAME)
out.Write([]byte(*flagBuildid))
var zero = make([]byte, 4)
out.Write(zero[:int(Rnd(int64(len(*flagBuildid)), 4)-int64(len(*flagBuildid)))])
return int(sh.size)
}
// Go specific notes
const (
ELF_NOTE_GOPKGLIST_TAG = 1
ELF_NOTE_GOABIHASH_TAG = 2
ELF_NOTE_GODEPS_TAG = 3
ELF_NOTE_GOBUILDID_TAG = 4
)
var ELF_NOTE_GO_NAME = []byte("Go\x00\x00")
var elfverneed int
type Elfaux struct {
next *Elfaux
num int
vers string
}
type Elflib struct {
next *Elflib
aux *Elfaux
file string
}
func addelflib(list **Elflib, file string, vers string) *Elfaux {
var lib *Elflib
for lib = *list; lib != nil; lib = lib.next {
if lib.file == file {
goto havelib
}
}
lib = new(Elflib)
lib.next = *list
lib.file = file
*list = lib
havelib:
for aux := lib.aux; aux != nil; aux = aux.next {
if aux.vers == vers {
return aux
}
}
aux := new(Elfaux)
aux.next = lib.aux
aux.vers = vers
lib.aux = aux
return aux
}
func elfdynhash(ctxt *Link) {
if !ctxt.IsELF {
return
}
nsym := Nelfsym
ldr := ctxt.loader
s := ldr.CreateSymForUpdate(".hash", 0)
s.SetType(sym.SELFROSECT)
i := nsym
nbucket := 1
for i > 0 {
nbucket++
i >>= 1
}
var needlib *Elflib
need := make([]*Elfaux, nsym)
chain := make([]uint32, nsym)
buckets := make([]uint32, nbucket)
for _, sy := range ldr.DynidSyms() {
dynid := ldr.SymDynid(sy)
if ldr.SymDynimpvers(sy) != "" {
need[dynid] = addelflib(&needlib, ldr.SymDynimplib(sy), ldr.SymDynimpvers(sy))
}
name := ldr.SymExtname(sy)
hc := elfhash(name)
b := hc % uint32(nbucket)
chain[dynid] = buckets[b]
buckets[b] = uint32(dynid)
}
// s390x (ELF64) hash table entries are 8 bytes
if ctxt.Arch.Family == sys.S390X {
s.AddUint64(ctxt.Arch, uint64(nbucket))
s.AddUint64(ctxt.Arch, uint64(nsym))
for i := 0; i < nbucket; i++ {
s.AddUint64(ctxt.Arch, uint64(buckets[i]))
}
for i := 0; i < nsym; i++ {
s.AddUint64(ctxt.Arch, uint64(chain[i]))
}
} else {
s.AddUint32(ctxt.Arch, uint32(nbucket))
s.AddUint32(ctxt.Arch, uint32(nsym))
for i := 0; i < nbucket; i++ {
s.AddUint32(ctxt.Arch, buckets[i])
}
for i := 0; i < nsym; i++ {
s.AddUint32(ctxt.Arch, chain[i])
}
}
dynstr := ldr.CreateSymForUpdate(".dynstr", 0)
// version symbols
gnuVersionR := ldr.CreateSymForUpdate(".gnu.version_r", 0)
s = gnuVersionR
i = 2
nfile := 0
for l := needlib; l != nil; l = l.next {
nfile++
// header
s.AddUint16(ctxt.Arch, 1) // table version
j := 0
for x := l.aux; x != nil; x = x.next {
j++
}
s.AddUint16(ctxt.Arch, uint16(j)) // aux count
s.AddUint32(ctxt.Arch, uint32(dynstr.Addstring(l.file))) // file string offset
s.AddUint32(ctxt.Arch, 16) // offset from header to first aux
if l.next != nil {
s.AddUint32(ctxt.Arch, 16+uint32(j)*16) // offset from this header to next
} else {
s.AddUint32(ctxt.Arch, 0)
}
for x := l.aux; x != nil; x = x.next {
x.num = i
i++
// aux struct
s.AddUint32(ctxt.Arch, elfhash(x.vers)) // hash
s.AddUint16(ctxt.Arch, 0) // flags
s.AddUint16(ctxt.Arch, uint16(x.num)) // other - index we refer to this by
s.AddUint32(ctxt.Arch, uint32(dynstr.Addstring(x.vers))) // version string offset
if x.next != nil {
s.AddUint32(ctxt.Arch, 16) // offset from this aux to next
} else {
s.AddUint32(ctxt.Arch, 0)
}
}
}
// version references
gnuVersion := ldr.CreateSymForUpdate(".gnu.version", 0)
s = gnuVersion
for i := 0; i < nsym; i++ {
if i == 0 {
s.AddUint16(ctxt.Arch, 0) // first entry - no symbol
} else if need[i] == nil {
s.AddUint16(ctxt.Arch, 1) // global
} else {
s.AddUint16(ctxt.Arch, uint16(need[i].num))
}
}
s = ldr.CreateSymForUpdate(".dynamic", 0)
elfverneed = nfile
if elfverneed != 0 {
elfWriteDynEntSym(ctxt, s, DT_VERNEED, gnuVersionR.Sym())
Elfwritedynent(ctxt.Arch, s, DT_VERNEEDNUM, uint64(nfile))
elfWriteDynEntSym(ctxt, s, DT_VERSYM, gnuVersion.Sym())
}
sy := ldr.CreateSymForUpdate(elfRelType+".plt", 0)
if sy.Size() > 0 {
if elfRelType == ".rela" {
Elfwritedynent(ctxt.Arch, s, DT_PLTREL, DT_RELA)
} else {
Elfwritedynent(ctxt.Arch, s, DT_PLTREL, DT_REL)
}
elfwritedynentsymsize(ctxt, s, DT_PLTRELSZ, sy.Sym())
elfWriteDynEntSym(ctxt, s, DT_JMPREL, sy.Sym())
}
Elfwritedynent(ctxt.Arch, s, DT_NULL, 0)
}
func elfphload(seg *sym.Segment) *ElfPhdr {
ph := newElfPhdr()
ph.type_ = PT_LOAD
if seg.Rwx&4 != 0 {
ph.flags |= PF_R
}
if seg.Rwx&2 != 0 {
ph.flags |= PF_W
}
if seg.Rwx&1 != 0 {
ph.flags |= PF_X
}
ph.vaddr = seg.Vaddr
ph.paddr = seg.Vaddr
ph.memsz = seg.Length
ph.off = seg.Fileoff
ph.filesz = seg.Filelen
ph.align = uint64(*FlagRound)
return ph
}
func elfphrelro(seg *sym.Segment) {
ph := newElfPhdr()
ph.type_ = PT_GNU_RELRO
ph.vaddr = seg.Vaddr
ph.paddr = seg.Vaddr
ph.memsz = seg.Length
ph.off = seg.Fileoff
ph.filesz = seg.Filelen
ph.align = uint64(*FlagRound)
}
func elfshname(name string) *ElfShdr {
for i := 0; i < nelfstr; i++ {
if name != elfstr[i].s {
continue
}
off := elfstr[i].off
for i = 0; i < int(ehdr.shnum); i++ {
sh := shdr[i]
if sh.name == uint32(off) {
return sh
}
}
return newElfShdr(int64(off))
}
Exitf("cannot find elf name %s", name)
return nil
}
// Create an ElfShdr for the section with name.
// Create a duplicate if one already exists with that name
func elfshnamedup(name string) *ElfShdr {
for i := 0; i < nelfstr; i++ {
if name == elfstr[i].s {
off := elfstr[i].off
return newElfShdr(int64(off))
}
}
Errorf(nil, "cannot find elf name %s", name)
errorexit()
return nil
}
func elfshalloc(sect *sym.Section) *ElfShdr {
sh := elfshname(sect.Name)
sect.Elfsect = sh
return sh
}
func elfshbits(linkmode LinkMode, sect *sym.Section) *ElfShdr {
var sh *ElfShdr
if sect.Name == ".text" {
if sect.Elfsect == nil {
sect.Elfsect = elfshnamedup(sect.Name)
}
sh = sect.Elfsect.(*ElfShdr)
} else {
sh = elfshalloc(sect)
}
// If this section has already been set up as a note, we assume type_ and
// flags are already correct, but the other fields still need filling in.
if sh.type_ == SHT_NOTE {
if linkmode != LinkExternal {
// TODO(mwhudson): the approach here will work OK when
// linking internally for notes that we want to be included
// in a loadable segment (e.g. the abihash note) but not for
// notes that we do not want to be mapped (e.g. the package
// list note). The real fix is probably to define new values
// for Symbol.Type corresponding to mapped and unmapped notes
// and handle them in dodata().
Errorf(nil, "sh.type_ == SHT_NOTE in elfshbits when linking internally")
}
sh.addralign = uint64(sect.Align)
sh.size = sect.Length
sh.off = sect.Seg.Fileoff + sect.Vaddr - sect.Seg.Vaddr
return sh
}
if sh.type_ > 0 {
return sh
}
if sect.Vaddr < sect.Seg.Vaddr+sect.Seg.Filelen {
sh.type_ = SHT_PROGBITS
} else {
sh.type_ = SHT_NOBITS
}
sh.flags = SHF_ALLOC
if sect.Rwx&1 != 0 {
sh.flags |= SHF_EXECINSTR
}
if sect.Rwx&2 != 0 {
sh.flags |= SHF_WRITE
}
if sect.Name == ".tbss" {
sh.flags |= SHF_TLS
sh.type_ = SHT_NOBITS
}
if strings.HasPrefix(sect.Name, ".debug") || strings.HasPrefix(sect.Name, ".zdebug") {
sh.flags = 0
}
if linkmode != LinkExternal {
sh.addr = sect.Vaddr
}
sh.addralign = uint64(sect.Align)
sh.size = sect.Length
if sect.Name != ".tbss" {
sh.off = sect.Seg.Fileoff + sect.Vaddr - sect.Seg.Vaddr
}
return sh
}
func elfshreloc(arch *sys.Arch, sect *sym.Section) *ElfShdr {
// If main section is SHT_NOBITS, nothing to relocate.
// Also nothing to relocate in .shstrtab or notes.
if sect.Vaddr >= sect.Seg.Vaddr+sect.Seg.Filelen {
return nil
}
if sect.Name == ".shstrtab" || sect.Name == ".tbss" {
return nil
}
if sect.Elfsect.(*ElfShdr).type_ == SHT_NOTE {
return nil
}
typ := SHT_REL
if elfRelType == ".rela" {
typ = SHT_RELA
}
sh := elfshname(elfRelType + sect.Name)
// There could be multiple text sections but each needs
// its own .rela.text.
if sect.Name == ".text" {
if sh.info != 0 && sh.info != uint32(sect.Elfsect.(*ElfShdr).shnum) {
sh = elfshnamedup(elfRelType + sect.Name)
}
}
sh.type_ = uint32(typ)
sh.entsize = uint64(arch.RegSize) * 2
if typ == SHT_RELA {
sh.entsize += uint64(arch.RegSize)
}
sh.link = uint32(elfshname(".symtab").shnum)
sh.info = uint32(sect.Elfsect.(*ElfShdr).shnum)
sh.off = sect.Reloff
sh.size = sect.Rellen
sh.addralign = uint64(arch.RegSize)
return sh
}
func elfrelocsect(ctxt *Link, out *OutBuf, sect *sym.Section, syms []loader.Sym) {
// If main section is SHT_NOBITS, nothing to relocate.
// Also nothing to relocate in .shstrtab.
if sect.Vaddr >= sect.Seg.Vaddr+sect.Seg.Filelen {
return
}
if sect.Name == ".shstrtab" {
return
}
ldr := ctxt.loader
for i, s := range syms {
if !ldr.AttrReachable(s) {
panic("should never happen")
}
if uint64(ldr.SymValue(s)) >= sect.Vaddr {
syms = syms[i:]
break
}
}
eaddr := int32(sect.Vaddr + sect.Length)
for _, s := range syms {
if !ldr.AttrReachable(s) {
continue
}
if ldr.SymValue(s) >= int64(eaddr) {
break
}
// Compute external relocations on the go, and pass to Elfreloc1
// 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 {
ldr.Errorf(s, "missing xsym in relocation")
continue
}
esr := ElfSymForReloc(ctxt, rr.Xsym)
if esr == 0 {
ldr.Errorf(s, "reloc %d (%s) to non-elf symbol %s (outer=%s) %d (%s)", r.Type(), sym.RelocName(ctxt.Arch, r.Type()), ldr.SymName(r.Sym()), ldr.SymName(rr.Xsym), ldr.SymType(r.Sym()), ldr.SymType(r.Sym()).String())
}
if !ldr.AttrReachable(rr.Xsym) {
ldr.Errorf(s, "unreachable reloc %d (%s) target %v", r.Type(), sym.RelocName(ctxt.Arch, r.Type()), ldr.SymName(rr.Xsym))
}
if !thearch.Elfreloc1(ctxt, out, ldr, s, rr, ri, int64(uint64(ldr.SymValue(s)+int64(r.Off()))-sect.Vaddr)) {
ldr.Errorf(s, "unsupported obj reloc %d (%s)/%d to %s", r.Type(), sym.RelocName(ctxt.Arch, r.Type()), r.Siz(), ldr.SymName(r.Sym()))
}
}
}
// sanity check
if uint64(out.Offset()) != sect.Reloff+sect.Rellen {
panic(fmt.Sprintf("elfrelocsect: size mismatch %d != %d + %d", out.Offset(), sect.Reloff, sect.Rellen))
}
}
func elfEmitReloc(ctxt *Link) {
for ctxt.Out.Offset()&7 != 0 {
ctxt.Out.Write8(0)
}
sizeExtRelocs(ctxt, thearch.ElfrelocSize)
relocSect, wg := relocSectFn(ctxt, elfrelocsect)
for _, sect := range Segtext.Sections {
if sect.Name == ".text" {
relocSect(ctxt, sect, ctxt.Textp)
} else {
relocSect(ctxt, sect, ctxt.datap)
}
}
for _, sect := range Segrodata.Sections {
relocSect(ctxt, sect, ctxt.datap)
}
for _, sect := range Segrelrodata.Sections {
relocSect(ctxt, sect, ctxt.datap)
}
for _, sect := range Segdata.Sections {
relocSect(ctxt, sect, ctxt.datap)
}
for i := 0; i < len(Segdwarf.Sections); i++ {
sect := Segdwarf.Sections[i]
si := dwarfp[i]
if si.secSym() != loader.Sym(sect.Sym) ||
ctxt.loader.SymSect(si.secSym()) != sect {
panic("inconsistency between dwarfp and Segdwarf")
}
relocSect(ctxt, sect, si.syms)
}
wg.Wait()
}
func addgonote(ctxt *Link, sectionName string, tag uint32, desc []byte) {
ldr := ctxt.loader
s := ldr.CreateSymForUpdate(sectionName, 0)
s.SetType(sym.SELFROSECT)
// namesz
s.AddUint32(ctxt.Arch, uint32(len(ELF_NOTE_GO_NAME)))
// descsz
s.AddUint32(ctxt.Arch, uint32(len(desc)))
// tag
s.AddUint32(ctxt.Arch, tag)
// name + padding
s.AddBytes(ELF_NOTE_GO_NAME)
for len(s.Data())%4 != 0 {
s.AddUint8(0)
}
// desc + padding
s.AddBytes(desc)
for len(s.Data())%4 != 0 {
s.AddUint8(0)
}
s.SetSize(int64(len(s.Data())))
s.SetAlign(4)
}
func (ctxt *Link) doelf() {
ldr := ctxt.loader
/* predefine strings we need for section headers */
shstrtab := ldr.CreateSymForUpdate(".shstrtab", 0)
shstrtab.SetType(sym.SELFROSECT)
shstrtab.Addstring("")
shstrtab.Addstring(".text")
shstrtab.Addstring(".noptrdata")
shstrtab.Addstring(".data")
shstrtab.Addstring(".bss")
shstrtab.Addstring(".noptrbss")
shstrtab.Addstring("__libfuzzer_extra_counters")
shstrtab.Addstring(".go.buildinfo")
// generate .tbss section for dynamic internal linker or external
// linking, so that various binutils could correctly calculate
// PT_TLS size. See https://golang.org/issue/5200.
if !*FlagD || ctxt.IsExternal() {
shstrtab.Addstring(".tbss")
}
if ctxt.IsNetbsd() {
shstrtab.Addstring(".note.netbsd.ident")
if *flagRace {
shstrtab.Addstring(".note.netbsd.pax")
}
}
if ctxt.IsOpenbsd() {
shstrtab.Addstring(".note.openbsd.ident")
}
if len(buildinfo) > 0 {
shstrtab.Addstring(".note.gnu.build-id")
}
if *flagBuildid != "" {
shstrtab.Addstring(".note.go.buildid")
}
shstrtab.Addstring(".elfdata")
shstrtab.Addstring(".rodata")
// See the comment about data.rel.ro.FOO section names in data.go.
relro_prefix := ""
if ctxt.UseRelro() {
shstrtab.Addstring(".data.rel.ro")
relro_prefix = ".data.rel.ro"
}
shstrtab.Addstring(relro_prefix + ".typelink")
shstrtab.Addstring(relro_prefix + ".itablink")
shstrtab.Addstring(relro_prefix + ".gosymtab")
shstrtab.Addstring(relro_prefix + ".gopclntab")
if ctxt.IsExternal() {
*FlagD = true
shstrtab.Addstring(elfRelType + ".text")
shstrtab.Addstring(elfRelType + ".rodata")
shstrtab.Addstring(elfRelType + relro_prefix + ".typelink")
shstrtab.Addstring(elfRelType + relro_prefix + ".itablink")
shstrtab.Addstring(elfRelType + relro_prefix + ".gosymtab")
shstrtab.Addstring(elfRelType + relro_prefix + ".gopclntab")
shstrtab.Addstring(elfRelType + ".noptrdata")
shstrtab.Addstring(elfRelType + ".data")
if ctxt.UseRelro() {
shstrtab.Addstring(elfRelType + ".data.rel.ro")
}
shstrtab.Addstring(elfRelType + ".go.buildinfo")
// add a .note.GNU-stack section to mark the stack as non-executable
shstrtab.Addstring(".note.GNU-stack")
if ctxt.IsShared() {
shstrtab.Addstring(".note.go.abihash")
shstrtab.Addstring(".note.go.pkg-list")
shstrtab.Addstring(".note.go.deps")
}
}
hasinitarr := ctxt.linkShared
/* shared library initializer */
switch ctxt.BuildMode {
case BuildModeCArchive, BuildModeCShared, BuildModeShared, BuildModePlugin:
hasinitarr = true
}
if hasinitarr {
shstrtab.Addstring(".init_array")
shstrtab.Addstring(elfRelType + ".init_array")
}
if !*FlagS {
shstrtab.Addstring(".symtab")
shstrtab.Addstring(".strtab")
dwarfaddshstrings(ctxt, shstrtab)
}
shstrtab.Addstring(".shstrtab")
if !*FlagD { /* -d suppresses dynamic loader format */
shstrtab.Addstring(".interp")
shstrtab.Addstring(".hash")
shstrtab.Addstring(".got")
if ctxt.IsPPC64() {
shstrtab.Addstring(".glink")
}
shstrtab.Addstring(".got.plt")
shstrtab.Addstring(".dynamic")
shstrtab.Addstring(".dynsym")
shstrtab.Addstring(".dynstr")
shstrtab.Addstring(elfRelType)
shstrtab.Addstring(elfRelType + ".plt")
shstrtab.Addstring(".plt")
shstrtab.Addstring(".gnu.version")
shstrtab.Addstring(".gnu.version_r")
/* dynamic symbol table - first entry all zeros */
dynsym := ldr.CreateSymForUpdate(".dynsym", 0)
dynsym.SetType(sym.SELFROSECT)
if elf64 {
dynsym.SetSize(dynsym.Size() + ELF64SYMSIZE)
} else {
dynsym.SetSize(dynsym.Size() + ELF32SYMSIZE)
}
/* dynamic string table */
dynstr := ldr.CreateSymForUpdate(".dynstr", 0)
dynstr.SetType(sym.SELFROSECT)
if dynstr.Size() == 0 {
dynstr.Addstring("")
}
/* relocation table */
s := ldr.CreateSymForUpdate(elfRelType, 0)
s.SetType(sym.SELFROSECT)
/* global offset table */
got := ldr.CreateSymForUpdate(".got", 0)
got.SetType(sym.SELFGOT) // writable
/* ppc64 glink resolver */
if ctxt.IsPPC64() {
s := ldr.CreateSymForUpdate(".glink", 0)
s.SetType(sym.SELFRXSECT)
}
/* hash */
hash := ldr.CreateSymForUpdate(".hash", 0)
hash.SetType(sym.SELFROSECT)
gotplt := ldr.CreateSymForUpdate(".got.plt", 0)
gotplt.SetType(sym.SELFSECT) // writable
plt := ldr.CreateSymForUpdate(".plt", 0)
if ctxt.IsPPC64() {
// In the ppc64 ABI, .plt is a data section
// written by the dynamic linker.
plt.SetType(sym.SELFSECT)
} else {
plt.SetType(sym.SELFRXSECT)
}
s = ldr.CreateSymForUpdate(elfRelType+".plt", 0)
s.SetType(sym.SELFROSECT)
s = ldr.CreateSymForUpdate(".gnu.version", 0)
s.SetType(sym.SELFROSECT)
s = ldr.CreateSymForUpdate(".gnu.version_r", 0)
s.SetType(sym.SELFROSECT)
/* define dynamic elf table */
dynamic := ldr.CreateSymForUpdate(".dynamic", 0)
dynamic.SetType(sym.SELFSECT) // writable
if ctxt.IsS390X() {
// S390X uses .got instead of .got.plt
gotplt = got
}
thearch.Elfsetupplt(ctxt, plt, gotplt, dynamic.Sym())
/*
* .dynamic table
*/
elfwritedynentsym(ctxt, dynamic, DT_HASH, hash.Sym())
elfwritedynentsym(ctxt, dynamic, DT_SYMTAB, dynsym.Sym())
if elf64 {
Elfwritedynent(ctxt.Arch, dynamic, DT_SYMENT, ELF64SYMSIZE)
} else {
Elfwritedynent(ctxt.Arch, dynamic, DT_SYMENT, ELF32SYMSIZE)
}
elfwritedynentsym(ctxt, dynamic, DT_STRTAB, dynstr.Sym())
elfwritedynentsymsize(ctxt, dynamic, DT_STRSZ, dynstr.Sym())
if elfRelType == ".rela" {
rela := ldr.LookupOrCreateSym(".rela", 0)
elfwritedynentsym(ctxt, dynamic, DT_RELA, rela)
elfwritedynentsymsize(ctxt, dynamic, DT_RELASZ, rela)
Elfwritedynent(ctxt.Arch, dynamic, DT_RELAENT, ELF64RELASIZE)
} else {
rel := ldr.LookupOrCreateSym(".rel", 0)
elfwritedynentsym(ctxt, dynamic, DT_REL, rel)
elfwritedynentsymsize(ctxt, dynamic, DT_RELSZ, rel)
Elfwritedynent(ctxt.Arch, dynamic, DT_RELENT, ELF32RELSIZE)
}
if rpath.val != "" {
Elfwritedynent(ctxt.Arch, dynamic, DT_RUNPATH, uint64(dynstr.Addstring(rpath.val)))
}
if ctxt.IsPPC64() {
elfwritedynentsym(ctxt, dynamic, DT_PLTGOT, plt.Sym())
} else {
elfwritedynentsym(ctxt, dynamic, DT_PLTGOT, gotplt.Sym())
}
if ctxt.IsPPC64() {
Elfwritedynent(ctxt.Arch, dynamic, DT_PPC64_OPT, 0)
}
// Solaris dynamic linker can't handle an empty .rela.plt if
// DT_JMPREL is emitted so we have to defer generation of DT_PLTREL,
// DT_PLTRELSZ, and DT_JMPREL dynamic entries until after we know the
// size of .rel(a).plt section.
Elfwritedynent(ctxt.Arch, dynamic, DT_DEBUG, 0)
}
if ctxt.IsShared() {
// The go.link.abihashbytes symbol will be pointed at the appropriate
// part of the .note.go.abihash section in data.go:func address().
s := ldr.LookupOrCreateSym("go.link.abihashbytes", 0)
sb := ldr.MakeSymbolUpdater(s)
ldr.SetAttrLocal(s, true)
sb.SetType(sym.SRODATA)
ldr.SetAttrSpecial(s, true)
sb.SetReachable(true)
sb.SetSize(sha1.Size)
sort.Sort(byPkg(ctxt.Library))
h := sha1.New()
for _, l := range ctxt.Library {
h.Write(l.Fingerprint[:])
}
addgonote(ctxt, ".note.go.abihash", ELF_NOTE_GOABIHASH_TAG, h.Sum([]byte{}))
addgonote(ctxt, ".note.go.pkg-list", ELF_NOTE_GOPKGLIST_TAG, pkglistfornote)
var deplist []string
for _, shlib := range ctxt.Shlibs {
deplist = append(deplist, filepath.Base(shlib.Path))
}
addgonote(ctxt, ".note.go.deps", ELF_NOTE_GODEPS_TAG, []byte(strings.Join(deplist, "\n")))
}
if ctxt.LinkMode == LinkExternal && *flagBuildid != "" {
addgonote(ctxt, ".note.go.buildid", ELF_NOTE_GOBUILDID_TAG, []byte(*flagBuildid))
}
}
// Do not write DT_NULL. elfdynhash will finish it.
func shsym(sh *ElfShdr, ldr *loader.Loader, s loader.Sym) {
if s == 0 {
panic("bad symbol in shsym2")
}
addr := ldr.SymValue(s)
if sh.flags&SHF_ALLOC != 0 {
sh.addr = uint64(addr)
}
sh.off = uint64(datoff(ldr, s, addr))
sh.size = uint64(ldr.SymSize(s))
}
func phsh(ph *ElfPhdr, sh *ElfShdr) {
ph.vaddr = sh.addr
ph.paddr = ph.vaddr
ph.off = sh.off
ph.filesz = sh.size
ph.memsz = sh.size
ph.align = sh.addralign
}
func Asmbelfsetup() {
/* This null SHdr must appear before all others */
elfshname("")
for _, sect := range Segtext.Sections {
// There could be multiple .text sections. Instead check the Elfsect
// field to determine if already has an ElfShdr and if not, create one.
if sect.Name == ".text" {
if sect.Elfsect == nil {
sect.Elfsect = elfshnamedup(sect.Name)
}
} else {
elfshalloc(sect)
}
}
for _, sect := range Segrodata.Sections {
elfshalloc(sect)
}
for _, sect := range Segrelrodata.Sections {
elfshalloc(sect)
}
for _, sect := range Segdata.Sections {
elfshalloc(sect)
}
for _, sect := range Segdwarf.Sections {
elfshalloc(sect)
}
}
func asmbElf(ctxt *Link) {
var symo int64
if !*FlagS {
symo = int64(Segdwarf.Fileoff + Segdwarf.Filelen)
symo = Rnd(symo, int64(ctxt.Arch.PtrSize))
ctxt.Out.SeekSet(symo)
asmElfSym(ctxt)
ctxt.Out.Write(Elfstrdat)
if ctxt.IsExternal() {
elfEmitReloc(ctxt)
}
}
ctxt.Out.SeekSet(0)
ldr := ctxt.loader
eh := getElfEhdr()
switch ctxt.Arch.Family {
default:
Exitf("unknown architecture in asmbelf: %v", ctxt.Arch.Family)
case sys.MIPS, sys.MIPS64:
eh.machine = EM_MIPS
case sys.ARM:
eh.machine = EM_ARM
case sys.AMD64:
eh.machine = EM_X86_64
case sys.ARM64:
eh.machine = EM_AARCH64
case sys.I386:
eh.machine = EM_386
case sys.PPC64:
eh.machine = EM_PPC64
case sys.RISCV64:
eh.machine = EM_RISCV
case sys.S390X:
eh.machine = EM_S390
}
elfreserve := int64(ELFRESERVE)
numtext := int64(0)
for _, sect := range Segtext.Sections {
if sect.Name == ".text" {
numtext++
}
}
// If there are multiple text sections, extra space is needed
// in the elfreserve for the additional .text and .rela.text
// section headers. It can handle 4 extra now. Headers are
// 64 bytes.
if numtext > 4 {
elfreserve += elfreserve + numtext*64*2
}
startva := *FlagTextAddr - int64(HEADR)
resoff := elfreserve
var pph *ElfPhdr
var pnote *ElfPhdr
if *flagRace && ctxt.IsNetbsd() {
sh := elfshname(".note.netbsd.pax")
resoff -= int64(elfnetbsdpax(sh, uint64(startva), uint64(resoff)))
pnote = newElfPhdr()
pnote.type_ = PT_NOTE
pnote.flags = PF_R
phsh(pnote, sh)
}
if ctxt.LinkMode == LinkExternal {
/* skip program headers */
eh.phoff = 0
eh.phentsize = 0
if ctxt.BuildMode == BuildModeShared {
sh := elfshname(".note.go.pkg-list")
sh.type_ = SHT_NOTE
sh = elfshname(".note.go.abihash")
sh.type_ = SHT_NOTE
sh.flags = SHF_ALLOC
sh = elfshname(".note.go.deps")
sh.type_ = SHT_NOTE
}
if *flagBuildid != "" {
sh := elfshname(".note.go.buildid")
sh.type_ = SHT_NOTE
sh.flags = SHF_ALLOC
}
goto elfobj
}
/* program header info */
pph = newElfPhdr()
pph.type_ = PT_PHDR
pph.flags = PF_R
pph.off = uint64(eh.ehsize)
pph.vaddr = uint64(*FlagTextAddr) - uint64(HEADR) + pph.off
pph.paddr = uint64(*FlagTextAddr) - uint64(HEADR) + pph.off
pph.align = uint64(*FlagRound)
/*
* PHDR must be in a loaded segment. Adjust the text
* segment boundaries downwards to include it.
*/
{
o := int64(Segtext.Vaddr - pph.vaddr)
Segtext.Vaddr -= uint64(o)
Segtext.Length += uint64(o)
o = int64(Segtext.Fileoff - pph.off)
Segtext.Fileoff -= uint64(o)
Segtext.Filelen += uint64(o)
}
if !*FlagD { /* -d suppresses dynamic loader format */
/* interpreter */
sh := elfshname(".interp")
sh.type_ = SHT_PROGBITS
sh.flags = SHF_ALLOC
sh.addralign = 1
if interpreter == "" && objabi.GO_LDSO != "" {
interpreter = objabi.GO_LDSO
}
if interpreter == "" {
switch ctxt.HeadType {
case objabi.Hlinux:
if objabi.GOOS == "android" {
interpreter = thearch.Androiddynld
if interpreter == "" {
Exitf("ELF interpreter not set")
}
} else {
interpreter = thearch.Linuxdynld
}
case objabi.Hfreebsd:
interpreter = thearch.Freebsddynld
case objabi.Hnetbsd:
interpreter = thearch.Netbsddynld
case objabi.Hopenbsd:
interpreter = thearch.Openbsddynld
case objabi.Hdragonfly:
interpreter = thearch.Dragonflydynld
case objabi.Hsolaris:
interpreter = thearch.Solarisdynld
}
}
resoff -= int64(elfinterp(sh, uint64(startva), uint64(resoff), interpreter))
ph := newElfPhdr()
ph.type_ = PT_INTERP
ph.flags = PF_R
phsh(ph, sh)
}
pnote = nil
if ctxt.HeadType == objabi.Hnetbsd || ctxt.HeadType == objabi.Hopenbsd {
var sh *ElfShdr
switch ctxt.HeadType {
case objabi.Hnetbsd:
sh = elfshname(".note.netbsd.ident")
resoff -= int64(elfnetbsdsig(sh, uint64(startva), uint64(resoff)))
case objabi.Hopenbsd:
sh = elfshname(".note.openbsd.ident")
resoff -= int64(elfopenbsdsig(sh, uint64(startva), uint64(resoff)))
}
pnote = newElfPhdr()
pnote.type_ = PT_NOTE
pnote.flags = PF_R
phsh(pnote, sh)
}
if len(buildinfo) > 0 {
sh := elfshname(".note.gnu.build-id")
resoff -= int64(elfbuildinfo(sh, uint64(startva), uint64(resoff)))
if pnote == nil {
pnote = newElfPhdr()
pnote.type_ = PT_NOTE
pnote.flags = PF_R
}
phsh(pnote, sh)
}
if *flagBuildid != "" {
sh := elfshname(".note.go.buildid")
resoff -= int64(elfgobuildid(sh, uint64(startva), uint64(resoff)))
pnote := newElfPhdr()
pnote.type_ = PT_NOTE
pnote.flags = PF_R
phsh(pnote, sh)
}
// Additions to the reserved area must be above this line.
elfphload(&Segtext)
if len(Segrodata.Sections) > 0 {
elfphload(&Segrodata)
}
if len(Segrelrodata.Sections) > 0 {
elfphload(&Segrelrodata)
elfphrelro(&Segrelrodata)
}
elfphload(&Segdata)
/* Dynamic linking sections */
if !*FlagD {
sh := elfshname(".dynsym")
sh.type_ = SHT_DYNSYM
sh.flags = SHF_ALLOC
if elf64 {
sh.entsize = ELF64SYMSIZE
} else {
sh.entsize = ELF32SYMSIZE
}
sh.addralign = uint64(ctxt.Arch.RegSize)
sh.link = uint32(elfshname(".dynstr").shnum)
// sh.info is the index of first non-local symbol (number of local symbols)
s := ldr.Lookup(".dynsym", 0)
i := uint32(0)
for sub := s; sub != 0; sub = ldr.SubSym(sub) {
i++
if !ldr.AttrLocal(sub) {
break
}
}
sh.info = i
shsym(sh, ldr, s)
sh = elfshname(".dynstr")
sh.type_ = SHT_STRTAB
sh.flags = SHF_ALLOC
sh.addralign = 1
shsym(sh, ldr, ldr.Lookup(".dynstr", 0))
if elfverneed != 0 {
sh := elfshname(".gnu.version")
sh.type_ = SHT_GNU_VERSYM
sh.flags = SHF_ALLOC
sh.addralign = 2
sh.link = uint32(elfshname(".dynsym").shnum)
sh.entsize = 2
shsym(sh, ldr, ldr.Lookup(".gnu.version", 0))
sh = elfshname(".gnu.version_r")
sh.type_ = SHT_GNU_VERNEED
sh.flags = SHF_ALLOC
sh.addralign = uint64(ctxt.Arch.RegSize)
sh.info = uint32(elfverneed)
sh.link = uint32(elfshname(".dynstr").shnum)
shsym(sh, ldr, ldr.Lookup(".gnu.version_r", 0))
}
if elfRelType == ".rela" {
sh := elfshname(".rela.plt")
sh.type_ = SHT_RELA
sh.flags = SHF_ALLOC
sh.entsize = ELF64RELASIZE
sh.addralign = uint64(ctxt.Arch.RegSize)
sh.link = uint32(elfshname(".dynsym").shnum)
sh.info = uint32(elfshname(".plt").shnum)
shsym(sh, ldr, ldr.Lookup(".rela.plt", 0))
sh = elfshname(".rela")
sh.type_ = SHT_RELA
sh.flags = SHF_ALLOC
sh.entsize = ELF64RELASIZE
sh.addralign = 8
sh.link = uint32(elfshname(".dynsym").shnum)
shsym(sh, ldr, ldr.Lookup(".rela", 0))
} else {
sh := elfshname(".rel.plt")
sh.type_ = SHT_REL
sh.flags = SHF_ALLOC
sh.entsize = ELF32RELSIZE
sh.addralign = 4
sh.link = uint32(elfshname(".dynsym").shnum)
shsym(sh, ldr, ldr.Lookup(".rel.plt", 0))
sh = elfshname(".rel")
sh.type_ = SHT_REL
sh.flags = SHF_ALLOC
sh.entsize = ELF32RELSIZE
sh.addralign = 4
sh.link = uint32(elfshname(".dynsym").shnum)
shsym(sh, ldr, ldr.Lookup(".rel", 0))
}
if eh.machine == EM_PPC64 {
sh := elfshname(".glink")
sh.type_ = SHT_PROGBITS
sh.flags = SHF_ALLOC + SHF_EXECINSTR
sh.addralign = 4
shsym(sh, ldr, ldr.Lookup(".glink", 0))
}
sh = elfshname(".plt")
sh.type_ = SHT_PROGBITS
sh.flags = SHF_ALLOC + SHF_EXECINSTR
if eh.machine == EM_X86_64 {
sh.entsize = 16
} else if eh.machine == EM_S390 {
sh.entsize = 32
} else if eh.machine == EM_PPC64 {
// On ppc64, this is just a table of addresses
// filled by the dynamic linker
sh.type_ = SHT_NOBITS
sh.flags = SHF_ALLOC + SHF_WRITE
sh.entsize = 8
} else {
sh.entsize = 4
}
sh.addralign = sh.entsize
shsym(sh, ldr, ldr.Lookup(".plt", 0))
// On ppc64, .got comes from the input files, so don't
// create it here, and .got.plt is not used.
if eh.machine != EM_PPC64 {
sh := elfshname(".got")
sh.type_ = SHT_PROGBITS
sh.flags = SHF_ALLOC + SHF_WRITE
sh.entsize = uint64(ctxt.Arch.RegSize)
sh.addralign = uint64(ctxt.Arch.RegSize)
shsym(sh, ldr, ldr.Lookup(".got", 0))
sh = elfshname(".got.plt")
sh.type_ = SHT_PROGBITS
sh.flags = SHF_ALLOC + SHF_WRITE
sh.entsize = uint64(ctxt.Arch.RegSize)
sh.addralign = uint64(ctxt.Arch.RegSize)
shsym(sh, ldr, ldr.Lookup(".got.plt", 0))
}
sh = elfshname(".hash")
sh.type_ = SHT_HASH
sh.flags = SHF_ALLOC
sh.entsize = 4
sh.addralign = uint64(ctxt.Arch.RegSize)
sh.link = uint32(elfshname(".dynsym").shnum)
shsym(sh, ldr, ldr.Lookup(".hash", 0))
/* sh and PT_DYNAMIC for .dynamic section */
sh = elfshname(".dynamic")
sh.type_ = SHT_DYNAMIC
sh.flags = SHF_ALLOC + SHF_WRITE
sh.entsize = 2 * uint64(ctxt.Arch.RegSize)
sh.addralign = uint64(ctxt.Arch.RegSize)
sh.link = uint32(elfshname(".dynstr").shnum)
shsym(sh, ldr, ldr.Lookup(".dynamic", 0))
ph := newElfPhdr()
ph.type_ = PT_DYNAMIC
ph.flags = PF_R + PF_W
phsh(ph, sh)
/*
* Thread-local storage segment (really just size).
*/
tlssize := uint64(0)
for _, sect := range Segdata.Sections {
if sect.Name == ".tbss" {
tlssize = sect.Length
}
}
if tlssize != 0 {
ph := newElfPhdr()
ph.type_ = PT_TLS
ph.flags = PF_R
ph.memsz = tlssize
ph.align = uint64(ctxt.Arch.RegSize)
}
}
if ctxt.HeadType == objabi.Hlinux {
ph := newElfPhdr()
ph.type_ = PT_GNU_STACK
ph.flags = PF_W + PF_R
ph.align = uint64(ctxt.Arch.RegSize)
ph = newElfPhdr()
ph.type_ = PT_PAX_FLAGS
ph.flags = 0x2a00 // mprotect, randexec, emutramp disabled
ph.align = uint64(ctxt.Arch.RegSize)
} else if ctxt.HeadType == objabi.Hsolaris {
ph := newElfPhdr()
ph.type_ = PT_SUNWSTACK
ph.flags = PF_W + PF_R
}
elfobj:
sh := elfshname(".shstrtab")
sh.type_ = SHT_STRTAB
sh.addralign = 1
shsym(sh, ldr, ldr.Lookup(".shstrtab", 0))
eh.shstrndx = uint16(sh.shnum)
// put these sections early in the list
if !*FlagS {
elfshname(".symtab")
elfshname(".strtab")
}
for _, sect := range Segtext.Sections {
elfshbits(ctxt.LinkMode, sect)
}
for _, sect := range Segrodata.Sections {
elfshbits(ctxt.LinkMode, sect)
}
for _, sect := range Segrelrodata.Sections {
elfshbits(ctxt.LinkMode, sect)
}
for _, sect := range Segdata.Sections {
elfshbits(ctxt.LinkMode, sect)
}
for _, sect := range Segdwarf.Sections {
elfshbits(ctxt.LinkMode, sect)
}
if ctxt.LinkMode == LinkExternal {
for _, sect := range Segtext.Sections {
elfshreloc(ctxt.Arch, sect)
}
for _, sect := range Segrodata.Sections {
elfshreloc(ctxt.Arch, sect)
}
for _, sect := range Segrelrodata.Sections {
elfshreloc(ctxt.Arch, sect)
}
for _, sect := range Segdata.Sections {
elfshreloc(ctxt.Arch, sect)
}
for _, si := range dwarfp {
sect := ldr.SymSect(si.secSym())
elfshreloc(ctxt.Arch, sect)
}
// add a .note.GNU-stack section to mark the stack as non-executable
sh := elfshname(".note.GNU-stack")
sh.type_ = SHT_PROGBITS
sh.addralign = 1
sh.flags = 0
}
if !*FlagS {
sh := elfshname(".symtab")
sh.type_ = SHT_SYMTAB
sh.off = uint64(symo)
sh.size = uint64(symSize)
sh.addralign = uint64(ctxt.Arch.RegSize)
sh.entsize = 8 + 2*uint64(ctxt.Arch.RegSize)
sh.link = uint32(elfshname(".strtab").shnum)
sh.info = uint32(elfglobalsymndx)
sh = elfshname(".strtab")
sh.type_ = SHT_STRTAB
sh.off = uint64(symo) + uint64(symSize)
sh.size = uint64(len(Elfstrdat))
sh.addralign = 1
}
/* Main header */
eh.ident[EI_MAG0] = '\177'
eh.ident[EI_MAG1] = 'E'
eh.ident[EI_MAG2] = 'L'
eh.ident[EI_MAG3] = 'F'
if ctxt.HeadType == objabi.Hfreebsd {
eh.ident[EI_OSABI] = ELFOSABI_FREEBSD
} else if ctxt.HeadType == objabi.Hnetbsd {
eh.ident[EI_OSABI] = ELFOSABI_NETBSD
} else if ctxt.HeadType == objabi.Hopenbsd {
eh.ident[EI_OSABI] = ELFOSABI_OPENBSD
} else if ctxt.HeadType == objabi.Hdragonfly {
eh.ident[EI_OSABI] = ELFOSABI_NONE
}
if elf64 {
eh.ident[EI_CLASS] = ELFCLASS64
} else {
eh.ident[EI_CLASS] = ELFCLASS32
}
if ctxt.Arch.ByteOrder == binary.BigEndian {
eh.ident[EI_DATA] = ELFDATA2MSB
} else {
eh.ident[EI_DATA] = ELFDATA2LSB
}
eh.ident[EI_VERSION] = EV_CURRENT
if ctxt.LinkMode == LinkExternal {
eh.type_ = ET_REL
} else if ctxt.BuildMode == BuildModePIE {
eh.type_ = ET_DYN
} else {
eh.type_ = ET_EXEC
}
if ctxt.LinkMode != LinkExternal {
eh.entry = uint64(Entryvalue(ctxt))
}
eh.version = EV_CURRENT
if pph != nil {
pph.filesz = uint64(eh.phnum) * uint64(eh.phentsize)
pph.memsz = pph.filesz
}
ctxt.Out.SeekSet(0)
a := int64(0)
a += int64(elfwritehdr(ctxt.Out))
a += int64(elfwritephdrs(ctxt.Out))
a += int64(elfwriteshdrs(ctxt.Out))
if !*FlagD {
a += int64(elfwriteinterp(ctxt.Out))
}
if ctxt.LinkMode != LinkExternal {
if ctxt.HeadType == objabi.Hnetbsd {
a += int64(elfwritenetbsdsig(ctxt.Out))
}
if ctxt.HeadType == objabi.Hopenbsd {
a += int64(elfwriteopenbsdsig(ctxt.Out))
}
if len(buildinfo) > 0 {
a += int64(elfwritebuildinfo(ctxt.Out))
}
if *flagBuildid != "" {
a += int64(elfwritegobuildid(ctxt.Out))
}
}
if *flagRace && ctxt.IsNetbsd() {
a += int64(elfwritenetbsdpax(ctxt.Out))
}
if a > elfreserve {
Errorf(nil, "ELFRESERVE too small: %d > %d with %d text sections", a, elfreserve, numtext)
}
}
func elfadddynsym(ldr *loader.Loader, target *Target, syms *ArchSyms, s loader.Sym) {
ldr.SetSymDynid(s, int32(Nelfsym))
Nelfsym++
d := ldr.MakeSymbolUpdater(syms.DynSym)
name := ldr.SymExtname(s)
dstru := ldr.MakeSymbolUpdater(syms.DynStr)
st := ldr.SymType(s)
cgoeStatic := ldr.AttrCgoExportStatic(s)
cgoeDynamic := ldr.AttrCgoExportDynamic(s)
cgoexp := (cgoeStatic || cgoeDynamic)
d.AddUint32(target.Arch, uint32(dstru.Addstring(name)))
if elf64 {
/* type */
t := STB_GLOBAL << 4
if cgoexp && st == sym.STEXT {
t |= STT_FUNC
} else {
t |= STT_OBJECT
}
d.AddUint8(uint8(t))
/* reserved */
d.AddUint8(0)
/* section where symbol is defined */
if st == sym.SDYNIMPORT {
d.AddUint16(target.Arch, SHN_UNDEF)
} else {
d.AddUint16(target.Arch, 1)
}
/* value */
if st == sym.SDYNIMPORT {
d.AddUint64(target.Arch, 0)
} else {
d.AddAddrPlus(target.Arch, s, 0)
}
/* size of object */
d.AddUint64(target.Arch, uint64(len(ldr.Data(s))))
dil := ldr.SymDynimplib(s)
if target.Arch.Family == sys.AMD64 && !cgoeDynamic && dil != "" && !seenlib[dil] {
du := ldr.MakeSymbolUpdater(syms.Dynamic)
Elfwritedynent(target.Arch, du, DT_NEEDED, uint64(dstru.Addstring(dil)))
seenlib[dil] = true
}
} else {
/* value */
if st == sym.SDYNIMPORT {
d.AddUint32(target.Arch, 0)
} else {
d.AddAddrPlus(target.Arch, s, 0)
}
/* size of object */
d.AddUint32(target.Arch, uint32(len(ldr.Data(s))))
/* type */
t := STB_GLOBAL << 4
// TODO(mwhudson): presumably the behavior should actually be the same on both arm and 386.
if target.Arch.Family == sys.I386 && cgoexp && st == sym.STEXT {
t |= STT_FUNC
} else if target.Arch.Family == sys.ARM && cgoeDynamic && st == sym.STEXT {
t |= STT_FUNC
} else {
t |= STT_OBJECT
}
d.AddUint8(uint8(t))
d.AddUint8(0)
/* shndx */
if st == sym.SDYNIMPORT {
d.AddUint16(target.Arch, SHN_UNDEF)
} else {
d.AddUint16(target.Arch, 1)
}
}
}
func ELF32_R_SYM(info uint32) uint32 {
return info >> 8
}
func ELF32_R_TYPE(info uint32) uint32 {
return uint32(uint8(info))
}
func ELF32_R_INFO(sym uint32, type_ uint32) uint32 {
return sym<<8 | type_
}
func ELF32_ST_BIND(info uint8) uint8 {
return info >> 4
}
func ELF32_ST_TYPE(info uint8) uint8 {
return info & 0xf
}
func ELF32_ST_INFO(bind uint8, type_ uint8) uint8 {
return bind<<4 | type_&0xf
}
func ELF32_ST_VISIBILITY(oth uint8) uint8 {
return oth & 3
}
func ELF64_R_SYM(info uint64) uint32 {
return uint32(info >> 32)
}
func ELF64_R_TYPE(info uint64) uint32 {
return uint32(info)
}
func ELF64_R_INFO(sym uint32, type_ uint32) uint64 {
return uint64(sym)<<32 | uint64(type_)
}
func ELF64_ST_BIND(info uint8) uint8 {
return info >> 4
}
func ELF64_ST_TYPE(info uint8) uint8 {
return info & 0xf
}
func ELF64_ST_INFO(bind uint8, type_ uint8) uint8 {
return bind<<4 | type_&0xf
}
func ELF64_ST_VISIBILITY(oth uint8) uint8 {
return oth & 3
}