Golang程序
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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/obj"
"crypto/sha1"
"encoding/binary"
"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 Elf_Note struct {
n_namesz uint32
n_descsz uint32
n_type 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
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_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_PAX_FLAGS = 0x65041580
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 (
R_X86_64_NONE = 0
R_X86_64_64 = 1
R_X86_64_PC32 = 2
R_X86_64_GOT32 = 3
R_X86_64_PLT32 = 4
R_X86_64_COPY = 5
R_X86_64_GLOB_DAT = 6
R_X86_64_JMP_SLOT = 7
R_X86_64_RELATIVE = 8
R_X86_64_GOTPCREL = 9
R_X86_64_32 = 10
R_X86_64_32S = 11
R_X86_64_16 = 12
R_X86_64_PC16 = 13
R_X86_64_8 = 14
R_X86_64_PC8 = 15
R_X86_64_DTPMOD64 = 16
R_X86_64_DTPOFF64 = 17
R_X86_64_TPOFF64 = 18
R_X86_64_TLSGD = 19
R_X86_64_TLSLD = 20
R_X86_64_DTPOFF32 = 21
R_X86_64_GOTTPOFF = 22
R_X86_64_TPOFF32 = 23
R_X86_64_COUNT = 24
R_AARCH64_ABS64 = 257
R_AARCH64_ABS32 = 258
R_AARCH64_CALL26 = 283
R_AARCH64_ADR_PREL_PG_HI21 = 275
R_AARCH64_ADD_ABS_LO12_NC = 277
R_ALPHA_NONE = 0
R_ALPHA_REFLONG = 1
R_ALPHA_REFQUAD = 2
R_ALPHA_GPREL32 = 3
R_ALPHA_LITERAL = 4
R_ALPHA_LITUSE = 5
R_ALPHA_GPDISP = 6
R_ALPHA_BRADDR = 7
R_ALPHA_HINT = 8
R_ALPHA_SREL16 = 9
R_ALPHA_SREL32 = 10
R_ALPHA_SREL64 = 11
R_ALPHA_OP_PUSH = 12
R_ALPHA_OP_STORE = 13
R_ALPHA_OP_PSUB = 14
R_ALPHA_OP_PRSHIFT = 15
R_ALPHA_GPVALUE = 16
R_ALPHA_GPRELHIGH = 17
R_ALPHA_GPRELLOW = 18
R_ALPHA_IMMED_GP_16 = 19
R_ALPHA_IMMED_GP_HI32 = 20
R_ALPHA_IMMED_SCN_HI32 = 21
R_ALPHA_IMMED_BR_HI32 = 22
R_ALPHA_IMMED_LO32 = 23
R_ALPHA_COPY = 24
R_ALPHA_GLOB_DAT = 25
R_ALPHA_JMP_SLOT = 26
R_ALPHA_RELATIVE = 27
R_ALPHA_COUNT = 28
R_ARM_NONE = 0
R_ARM_PC24 = 1
R_ARM_ABS32 = 2
R_ARM_REL32 = 3
R_ARM_PC13 = 4
R_ARM_ABS16 = 5
R_ARM_ABS12 = 6
R_ARM_THM_ABS5 = 7
R_ARM_ABS8 = 8
R_ARM_SBREL32 = 9
R_ARM_THM_PC22 = 10
R_ARM_THM_PC8 = 11
R_ARM_AMP_VCALL9 = 12
R_ARM_SWI24 = 13
R_ARM_THM_SWI8 = 14
R_ARM_XPC25 = 15
R_ARM_THM_XPC22 = 16
R_ARM_COPY = 20
R_ARM_GLOB_DAT = 21
R_ARM_JUMP_SLOT = 22
R_ARM_RELATIVE = 23
R_ARM_GOTOFF = 24
R_ARM_GOTPC = 25
R_ARM_GOT32 = 26
R_ARM_PLT32 = 27
R_ARM_CALL = 28
R_ARM_JUMP24 = 29
R_ARM_V4BX = 40
R_ARM_GOT_PREL = 96
R_ARM_GNU_VTENTRY = 100
R_ARM_GNU_VTINHERIT = 101
R_ARM_TLS_IE32 = 107
R_ARM_TLS_LE32 = 108
R_ARM_RSBREL32 = 250
R_ARM_THM_RPC22 = 251
R_ARM_RREL32 = 252
R_ARM_RABS32 = 253
R_ARM_RPC24 = 254
R_ARM_RBASE = 255
R_ARM_COUNT = 38
R_386_NONE = 0
R_386_32 = 1
R_386_PC32 = 2
R_386_GOT32 = 3
R_386_PLT32 = 4
R_386_COPY = 5
R_386_GLOB_DAT = 6
R_386_JMP_SLOT = 7
R_386_RELATIVE = 8
R_386_GOTOFF = 9
R_386_GOTPC = 10
R_386_TLS_TPOFF = 14
R_386_TLS_IE = 15
R_386_TLS_GOTIE = 16
R_386_TLS_LE = 17
R_386_TLS_GD = 18
R_386_TLS_LDM = 19
R_386_TLS_GD_32 = 24
R_386_TLS_GD_PUSH = 25
R_386_TLS_GD_CALL = 26
R_386_TLS_GD_POP = 27
R_386_TLS_LDM_32 = 28
R_386_TLS_LDM_PUSH = 29
R_386_TLS_LDM_CALL = 30
R_386_TLS_LDM_POP = 31
R_386_TLS_LDO_32 = 32
R_386_TLS_IE_32 = 33
R_386_TLS_LE_32 = 34
R_386_TLS_DTPMOD32 = 35
R_386_TLS_DTPOFF32 = 36
R_386_TLS_TPOFF32 = 37
R_386_COUNT = 38
R_PPC_NONE = 0
R_PPC_ADDR32 = 1
R_PPC_ADDR24 = 2
R_PPC_ADDR16 = 3
R_PPC_ADDR16_LO = 4
R_PPC_ADDR16_HI = 5
R_PPC_ADDR16_HA = 6
R_PPC_ADDR14 = 7
R_PPC_ADDR14_BRTAKEN = 8
R_PPC_ADDR14_BRNTAKEN = 9
R_PPC_REL24 = 10
R_PPC_REL14 = 11
R_PPC_REL14_BRTAKEN = 12
R_PPC_REL14_BRNTAKEN = 13
R_PPC_GOT16 = 14
R_PPC_GOT16_LO = 15
R_PPC_GOT16_HI = 16
R_PPC_GOT16_HA = 17
R_PPC_PLTREL24 = 18
R_PPC_COPY = 19
R_PPC_GLOB_DAT = 20
R_PPC_JMP_SLOT = 21
R_PPC_RELATIVE = 22
R_PPC_LOCAL24PC = 23
R_PPC_UADDR32 = 24
R_PPC_UADDR16 = 25
R_PPC_REL32 = 26
R_PPC_PLT32 = 27
R_PPC_PLTREL32 = 28
R_PPC_PLT16_LO = 29
R_PPC_PLT16_HI = 30
R_PPC_PLT16_HA = 31
R_PPC_SDAREL16 = 32
R_PPC_SECTOFF = 33
R_PPC_SECTOFF_LO = 34
R_PPC_SECTOFF_HI = 35
R_PPC_SECTOFF_HA = 36
R_PPC_COUNT = 37
R_PPC_TLS = 67
R_PPC_DTPMOD32 = 68
R_PPC_TPREL16 = 69
R_PPC_TPREL16_LO = 70
R_PPC_TPREL16_HI = 71
R_PPC_TPREL16_HA = 72
R_PPC_TPREL32 = 73
R_PPC_DTPREL16 = 74
R_PPC_DTPREL16_LO = 75
R_PPC_DTPREL16_HI = 76
R_PPC_DTPREL16_HA = 77
R_PPC_DTPREL32 = 78
R_PPC_GOT_TLSGD16 = 79
R_PPC_GOT_TLSGD16_LO = 80
R_PPC_GOT_TLSGD16_HI = 81
R_PPC_GOT_TLSGD16_HA = 82
R_PPC_GOT_TLSLD16 = 83
R_PPC_GOT_TLSLD16_LO = 84
R_PPC_GOT_TLSLD16_HI = 85
R_PPC_GOT_TLSLD16_HA = 86
R_PPC_GOT_TPREL16 = 87
R_PPC_GOT_TPREL16_LO = 88
R_PPC_GOT_TPREL16_HI = 89
R_PPC_GOT_TPREL16_HA = 90
R_PPC_EMB_NADDR32 = 101
R_PPC_EMB_NADDR16 = 102
R_PPC_EMB_NADDR16_LO = 103
R_PPC_EMB_NADDR16_HI = 104
R_PPC_EMB_NADDR16_HA = 105
R_PPC_EMB_SDAI16 = 106
R_PPC_EMB_SDA2I16 = 107
R_PPC_EMB_SDA2REL = 108
R_PPC_EMB_SDA21 = 109
R_PPC_EMB_MRKREF = 110
R_PPC_EMB_RELSEC16 = 111
R_PPC_EMB_RELST_LO = 112
R_PPC_EMB_RELST_HI = 113
R_PPC_EMB_RELST_HA = 114
R_PPC_EMB_BIT_FLD = 115
R_PPC_EMB_RELSDA = 116
R_PPC_EMB_COUNT = R_PPC_EMB_RELSDA - R_PPC_EMB_NADDR32 + 1
R_PPC64_REL24 = R_PPC_REL24
R_PPC64_JMP_SLOT = R_PPC_JMP_SLOT
R_PPC64_ADDR64 = 38
R_PPC64_TOC16 = 47
R_PPC64_TOC16_LO = 48
R_PPC64_TOC16_HI = 49
R_PPC64_TOC16_HA = 50
R_PPC64_TOC16_DS = 63
R_PPC64_TOC16_LO_DS = 64
R_PPC64_REL16_LO = 250
R_PPC64_REL16_HI = 251
R_PPC64_REL16_HA = 252
R_SPARC_NONE = 0
R_SPARC_8 = 1
R_SPARC_16 = 2
R_SPARC_32 = 3
R_SPARC_DISP8 = 4
R_SPARC_DISP16 = 5
R_SPARC_DISP32 = 6
R_SPARC_WDISP30 = 7
R_SPARC_WDISP22 = 8
R_SPARC_HI22 = 9
R_SPARC_22 = 10
R_SPARC_13 = 11
R_SPARC_LO10 = 12
R_SPARC_GOT10 = 13
R_SPARC_GOT13 = 14
R_SPARC_GOT22 = 15
R_SPARC_PC10 = 16
R_SPARC_PC22 = 17
R_SPARC_WPLT30 = 18
R_SPARC_COPY = 19
R_SPARC_GLOB_DAT = 20
R_SPARC_JMP_SLOT = 21
R_SPARC_RELATIVE = 22
R_SPARC_UA32 = 23
R_SPARC_PLT32 = 24
R_SPARC_HIPLT22 = 25
R_SPARC_LOPLT10 = 26
R_SPARC_PCPLT32 = 27
R_SPARC_PCPLT22 = 28
R_SPARC_PCPLT10 = 29
R_SPARC_10 = 30
R_SPARC_11 = 31
R_SPARC_64 = 32
R_SPARC_OLO10 = 33
R_SPARC_HH22 = 34
R_SPARC_HM10 = 35
R_SPARC_LM22 = 36
R_SPARC_PC_HH22 = 37
R_SPARC_PC_HM10 = 38
R_SPARC_PC_LM22 = 39
R_SPARC_WDISP16 = 40
R_SPARC_WDISP19 = 41
R_SPARC_GLOB_JMP = 42
R_SPARC_7 = 43
R_SPARC_5 = 44
R_SPARC_6 = 45
R_SPARC_DISP64 = 46
R_SPARC_PLT64 = 47
R_SPARC_HIX22 = 48
R_SPARC_LOX10 = 49
R_SPARC_H44 = 50
R_SPARC_M44 = 51
R_SPARC_L44 = 52
R_SPARC_REGISTER = 53
R_SPARC_UA64 = 54
R_SPARC_UA16 = 55
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
secsym *LSym
}
/*
* 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 = 48
)
var Iself bool
var Nelfsym int = 1
var elf64 bool
var ehdr ElfEhdr
var phdr [NSECT]*ElfPhdr
var shdr [NSECT]*ElfShdr
var 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() {
Iself = true
switch Thearch.Thechar {
// 64-bit architectures
case '9':
if Ctxt.Arch.ByteOrder == binary.BigEndian {
ehdr.flags = 1 /* Version 1 ABI */
} else {
ehdr.flags = 2 /* Version 2 ABI */
}
fallthrough
case '6', '7':
elf64 = true
ehdr.phoff = ELF64HDRSIZE /* Must be 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 */
// we use EABI on both linux/arm and freebsd/arm.
// 32-bit architectures
case '5':
// we use EABI on both linux/arm and freebsd/arm.
if HEADTYPE == obj.Hlinux || HEADTYPE == obj.Hfreebsd {
ehdr.flags = 0x5000002 // has entry point, Version5 EABI
}
fallthrough
default:
ehdr.phoff = ELF32HDRSIZE
/* Must be 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 */
}
}
func elf64phdr(e *ElfPhdr) {
Thearch.Lput(e.type_)
Thearch.Lput(e.flags)
Thearch.Vput(e.off)
Thearch.Vput(e.vaddr)
Thearch.Vput(e.paddr)
Thearch.Vput(e.filesz)
Thearch.Vput(e.memsz)
Thearch.Vput(e.align)
}
func elf32phdr(e *ElfPhdr) {
if e.type_ == PT_LOAD {
// Correct ELF loaders will do this implicitly,
// but buggy ELF loaders like the one in some
// versions of QEMU won't.
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)
}
Thearch.Lput(e.type_)
Thearch.Lput(uint32(e.off))
Thearch.Lput(uint32(e.vaddr))
Thearch.Lput(uint32(e.paddr))
Thearch.Lput(uint32(e.filesz))
Thearch.Lput(uint32(e.memsz))
Thearch.Lput(e.flags)
Thearch.Lput(uint32(e.align))
}
func elf64shdr(e *ElfShdr) {
Thearch.Lput(e.name)
Thearch.Lput(e.type_)
Thearch.Vput(e.flags)
Thearch.Vput(e.addr)
Thearch.Vput(e.off)
Thearch.Vput(e.size)
Thearch.Lput(e.link)
Thearch.Lput(e.info)
Thearch.Vput(e.addralign)
Thearch.Vput(e.entsize)
}
func elf32shdr(e *ElfShdr) {
Thearch.Lput(e.name)
Thearch.Lput(e.type_)
Thearch.Lput(uint32(e.flags))
Thearch.Lput(uint32(e.addr))
Thearch.Lput(uint32(e.off))
Thearch.Lput(uint32(e.size))
Thearch.Lput(e.link)
Thearch.Lput(e.info)
Thearch.Lput(uint32(e.addralign))
Thearch.Lput(uint32(e.entsize))
}
func elfwriteshdrs() uint32 {
if elf64 {
for i := 0; i < int(ehdr.shnum); i++ {
elf64shdr(shdr[i])
}
return uint32(ehdr.shnum) * ELF64SHDRSIZE
}
for i := 0; i < int(ehdr.shnum); i++ {
elf32shdr(shdr[i])
}
return uint32(ehdr.shnum) * ELF32SHDRSIZE
}
func elfsetstring(s string, off int) {
if nelfstr >= len(elfstr) {
Diag("too many elf strings")
errorexit()
}
elfstr[nelfstr].s = s
elfstr[nelfstr].off = off
nelfstr++
}
func elfwritephdrs() uint32 {
if elf64 {
for i := 0; i < int(ehdr.phnum); i++ {
elf64phdr(phdr[i])
}
return uint32(ehdr.phnum) * ELF64PHDRSIZE
}
for i := 0; i < int(ehdr.phnum); i++ {
elf32phdr(phdr[i])
}
return uint32(ehdr.phnum) * ELF32PHDRSIZE
}
func newElfPhdr() *ElfPhdr {
e := new(ElfPhdr)
if ehdr.phnum >= NSECT {
Diag("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 {
Diag("too many shdrs")
} else {
shdr[ehdr.shnum] = e
ehdr.shnum++
}
return e
}
func getElfEhdr() *ElfEhdr {
return &ehdr
}
func elf64writehdr() uint32 {
for i := 0; i < EI_NIDENT; i++ {
Cput(ehdr.ident[i])
}
Thearch.Wput(ehdr.type_)
Thearch.Wput(ehdr.machine)
Thearch.Lput(ehdr.version)
Thearch.Vput(ehdr.entry)
Thearch.Vput(ehdr.phoff)
Thearch.Vput(ehdr.shoff)
Thearch.Lput(ehdr.flags)
Thearch.Wput(ehdr.ehsize)
Thearch.Wput(ehdr.phentsize)
Thearch.Wput(ehdr.phnum)
Thearch.Wput(ehdr.shentsize)
Thearch.Wput(ehdr.shnum)
Thearch.Wput(ehdr.shstrndx)
return ELF64HDRSIZE
}
func elf32writehdr() uint32 {
for i := 0; i < EI_NIDENT; i++ {
Cput(ehdr.ident[i])
}
Thearch.Wput(ehdr.type_)
Thearch.Wput(ehdr.machine)
Thearch.Lput(ehdr.version)
Thearch.Lput(uint32(ehdr.entry))
Thearch.Lput(uint32(ehdr.phoff))
Thearch.Lput(uint32(ehdr.shoff))
Thearch.Lput(ehdr.flags)
Thearch.Wput(ehdr.ehsize)
Thearch.Wput(ehdr.phentsize)
Thearch.Wput(ehdr.phnum)
Thearch.Wput(ehdr.shentsize)
Thearch.Wput(ehdr.shnum)
Thearch.Wput(ehdr.shstrndx)
return ELF32HDRSIZE
}
func elfwritehdr() uint32 {
if elf64 {
return elf64writehdr()
}
return elf32writehdr()
}
/* Taken directly from the definition document for ELF64 */
func elfhash(name []byte) uint32 {
var h uint32 = 0
var g uint32
for len(name) != 0 {
h = (h << 4) + uint32(name[0])
name = name[1:]
g = h & 0xf0000000
if g != 0 {
h ^= g >> 24
}
h &= 0x0fffffff
}
return h
}
func Elfwritedynent(s *LSym, tag int, val uint64) {
if elf64 {
Adduint64(Ctxt, s, uint64(tag))
Adduint64(Ctxt, s, val)
} else {
Adduint32(Ctxt, s, uint32(tag))
Adduint32(Ctxt, s, uint32(val))
}
}
func elfwritedynentsym(s *LSym, tag int, t *LSym) {
Elfwritedynentsymplus(s, tag, t, 0)
}
func Elfwritedynentsymplus(s *LSym, tag int, t *LSym, add int64) {
if elf64 {
Adduint64(Ctxt, s, uint64(tag))
} else {
Adduint32(Ctxt, s, uint32(tag))
}
Addaddrplus(Ctxt, s, t, add)
}
func elfwritedynentsymsize(s *LSym, tag int, t *LSym) {
if elf64 {
Adduint64(Ctxt, s, uint64(tag))
} else {
Adduint32(Ctxt, s, uint32(tag))
}
addsize(Ctxt, s, 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() int {
sh := elfshname(".interp")
Cseek(int64(sh.off))
coutbuf.WriteString(interp)
Cput(0)
return int(sh.size)
}
func elfnote(sh *ElfShdr, startva uint64, resoff uint64, sz int, alloc bool) int {
n := 3*4 + uint64(sz) + resoff%4
sh.type_ = SHT_NOTE
if alloc {
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(str string, namesz uint32, descsz uint32, tag uint32) *ElfShdr {
sh := elfshname(str)
// Write Elf_Note header.
Cseek(int64(sh.off))
Thearch.Lput(namesz)
Thearch.Lput(descsz)
Thearch.Lput(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 = 599000000 /* NetBSD 5.99 */
)
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, true)
}
func elfwritenetbsdsig() int {
// Write Elf_Note header.
sh := elfwritenotehdr(".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.
Cwrite(ELF_NOTE_NETBSD_NAME)
Cput(0)
Thearch.Lput(ELF_NOTE_NETBSD_VERSION)
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, true)
}
func elfwriteopenbsdsig() int {
// Write Elf_Note header.
sh := elfwritenotehdr(".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.
Cwrite(ELF_NOTE_OPENBSD_NAME)
Thearch.Lput(ELF_NOTE_OPENBSD_VERSION)
return int(sh.size)
}
func addbuildinfo(val string) {
var j int
if val[0] != '0' || val[1] != 'x' {
Exitf("-B argument must start with 0x: %s", val)
}
ov := val
val = val[2:]
i := 0
var b int
for val != "" {
if len(val) == 1 {
Exitf("-B argument must have even number of digits: %s", ov)
}
b = 0
for j = 0; j < 2; j, val = j+1, val[1:] {
b *= 16
if val[0] >= '0' && val[0] <= '9' {
b += int(val[0]) - '0'
} else if val[0] >= 'a' && val[0] <= 'f' {
b += int(val[0]) - 'a' + 10
} else if val[0] >= 'A' && val[0] <= 'F' {
b += int(val[0]) - 'A' + 10
} else {
Exitf("-B argument contains invalid hex digit %c: %s", val[0], ov)
}
}
const maxLen = 32
if i >= maxLen {
Exitf("-B option too long (max %d digits): %s", maxLen, ov)
}
buildinfo = append(buildinfo, uint8(b))
i++
}
buildinfo = buildinfo[:i]
}
// 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, true)
}
func elfgobuildid(sh *ElfShdr, startva uint64, resoff uint64) int {
n := len(ELF_NOTE_GO_NAME) + int(Rnd(int64(len(buildid)), 4))
return elfnote(sh, startva, resoff, n, true)
}
func elfwritebuildinfo() int {
sh := elfwritenotehdr(".note.gnu.build-id", ELF_NOTE_BUILDINFO_NAMESZ, uint32(len(buildinfo)), ELF_NOTE_BUILDINFO_TAG)
if sh == nil {
return 0
}
Cwrite(ELF_NOTE_BUILDINFO_NAME)
Cwrite(buildinfo)
var zero = make([]byte, 4)
Cwrite(zero[:int(Rnd(int64(len(buildinfo)), 4)-int64(len(buildinfo)))])
return int(sh.size)
}
func elfwritegobuildid() int {
sh := elfwritenotehdr(".note.go.buildid", uint32(len(ELF_NOTE_GO_NAME)), uint32(len(buildid)), ELF_NOTE_GOBUILDID_TAG)
if sh == nil {
return 0
}
Cwrite(ELF_NOTE_GO_NAME)
Cwrite([]byte(buildid))
var zero = make([]byte, 4)
Cwrite(zero[:int(Rnd(int64(len(buildid)), 4)-int64(len(buildid)))])
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() {
if !Iself {
return
}
nsym := Nelfsym
s := Linklookup(Ctxt, ".hash", 0)
s.Type = obj.SELFROSECT
s.Reachable = true
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)
var b int
var hc uint32
var name string
for sy := Ctxt.Allsym; sy != nil; sy = sy.Allsym {
if sy.Dynid <= 0 {
continue
}
if sy.Dynimpvers != "" {
need[sy.Dynid] = addelflib(&needlib, sy.Dynimplib, sy.Dynimpvers)
}
name = sy.Extname
hc = elfhash([]byte(name))
b = int(hc % uint32(nbucket))
chain[sy.Dynid] = buckets[b]
buckets[b] = uint32(sy.Dynid)
}
Adduint32(Ctxt, s, uint32(nbucket))
Adduint32(Ctxt, s, uint32(nsym))
for i := 0; i < nbucket; i++ {
Adduint32(Ctxt, s, buckets[i])
}
for i := 0; i < nsym; i++ {
Adduint32(Ctxt, s, chain[i])
}
// version symbols
dynstr := Linklookup(Ctxt, ".dynstr", 0)
s = Linklookup(Ctxt, ".gnu.version_r", 0)
i = 2
nfile := 0
var j int
var x *Elfaux
for l := needlib; l != nil; l = l.next {
nfile++
// header
Adduint16(Ctxt, s, 1) // table version
j = 0
for x = l.aux; x != nil; x = x.next {
j++
}
Adduint16(Ctxt, s, uint16(j)) // aux count
Adduint32(Ctxt, s, uint32(Addstring(dynstr, l.file))) // file string offset
Adduint32(Ctxt, s, 16) // offset from header to first aux
if l.next != nil {
Adduint32(Ctxt, s, 16+uint32(j)*16) // offset from this header to next
} else {
Adduint32(Ctxt, s, 0)
}
for x = l.aux; x != nil; x = x.next {
x.num = i
i++
// aux struct
Adduint32(Ctxt, s, elfhash([]byte(x.vers))) // hash
Adduint16(Ctxt, s, 0) // flags
Adduint16(Ctxt, s, uint16(x.num)) // other - index we refer to this by
Adduint32(Ctxt, s, uint32(Addstring(dynstr, x.vers))) // version string offset
if x.next != nil {
Adduint32(Ctxt, s, 16) // offset from this aux to next
} else {
Adduint32(Ctxt, s, 0)
}
}
}
// version references
s = Linklookup(Ctxt, ".gnu.version", 0)
for i := 0; i < nsym; i++ {
if i == 0 {
Adduint16(Ctxt, s, 0) // first entry - no symbol
} else if need[i] == nil {
Adduint16(Ctxt, s, 1) // global
} else {
Adduint16(Ctxt, s, uint16(need[i].num))
}
}
s = Linklookup(Ctxt, ".dynamic", 0)
elfverneed = nfile
if elfverneed != 0 {
elfwritedynentsym(s, DT_VERNEED, Linklookup(Ctxt, ".gnu.version_r", 0))
Elfwritedynent(s, DT_VERNEEDNUM, uint64(nfile))
elfwritedynentsym(s, DT_VERSYM, Linklookup(Ctxt, ".gnu.version", 0))
}
switch Thearch.Thechar {
case '6', '7', '9':
sy := Linklookup(Ctxt, ".rela.plt", 0)
if sy.Size > 0 {
Elfwritedynent(s, DT_PLTREL, DT_RELA)
elfwritedynentsymsize(s, DT_PLTRELSZ, sy)
elfwritedynentsym(s, DT_JMPREL, sy)
}
default:
sy := Linklookup(Ctxt, ".rel.plt", 0)
if sy.Size > 0 {
Elfwritedynent(s, DT_PLTREL, DT_REL)
elfwritedynentsymsize(s, DT_PLTRELSZ, sy)
elfwritedynentsym(s, DT_JMPREL, sy)
}
}
Elfwritedynent(s, DT_NULL, 0)
}
func elfphload(seg *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(INITRND)
return ph
}
func elfshname(name string) *ElfShdr {
var off int
var sh *ElfShdr
for i := 0; i < nelfstr; i++ {
if name == elfstr[i].s {
off = elfstr[i].off
for i = 0; i < int(ehdr.shnum); i++ {
sh = shdr[i]
if sh.name == uint32(off) {
return sh
}
}
sh = newElfShdr(int64(off))
return sh
}
}
Diag("cannot find elf name %s", name)
errorexit()
return nil
}
func elfshalloc(sect *Section) *ElfShdr {
sh := elfshname(sect.Name)
sect.Elfsect = sh
return sh
}
func elfshbits(sect *Section) *ElfShdr {
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 LSym.Type corresponding to mapped and unmapped notes
// and handle them in dodata().
Diag("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" {
if goos != "android" {
sh.flags |= SHF_TLS // no TLS on android
}
sh.type_ = SHT_NOBITS
}
if Linkmode != LinkExternal {
sh.addr = sect.Vaddr
}
sh.addralign = uint64(sect.Align)
sh.size = sect.Length
sh.off = sect.Seg.Fileoff + sect.Vaddr - sect.Seg.Vaddr
return sh
}
func elfshreloc(sect *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.type_ == SHT_NOTE {
return nil
}
var prefix string
var typ int
switch Thearch.Thechar {
case '6', '7', '9':
prefix = ".rela"
typ = SHT_RELA
default:
prefix = ".rel"
typ = SHT_REL
}
buf := fmt.Sprintf("%s%s", prefix, sect.Name)
sh := elfshname(buf)
sh.type_ = uint32(typ)
sh.entsize = uint64(Thearch.Regsize) * 2
if typ == SHT_RELA {
sh.entsize += uint64(Thearch.Regsize)
}
sh.link = uint32(elfshname(".symtab").shnum)
sh.info = uint32(sect.Elfsect.shnum)
sh.off = sect.Reloff
sh.size = sect.Rellen
sh.addralign = uint64(Thearch.Regsize)
return sh
}
func elfrelocsect(sect *Section, first *LSym) {
// 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
}
sect.Reloff = uint64(Cpos())
var sym *LSym
for sym = first; sym != nil; sym = sym.Next {
if !sym.Reachable {
continue
}
if uint64(sym.Value) >= sect.Vaddr {
break
}
}
eaddr := int32(sect.Vaddr + sect.Length)
var r *Reloc
var ri int
for ; sym != nil; sym = sym.Next {
if !sym.Reachable {
continue
}
if sym.Value >= int64(eaddr) {
break
}
Ctxt.Cursym = sym
for ri = 0; ri < len(sym.R); ri++ {
r = &sym.R[ri]
if r.Done != 0 {
continue
}
if r.Xsym == nil {
Diag("missing xsym in relocation")
continue
}
if r.Xsym.Elfsym == 0 {
Diag("reloc %d to non-elf symbol %s (outer=%s) %d", r.Type, r.Sym.Name, r.Xsym.Name, r.Sym.Type)
}
if Thearch.Elfreloc1(r, int64(uint64(sym.Value+int64(r.Off))-sect.Vaddr)) < 0 {
Diag("unsupported obj reloc %d/%d to %s", r.Type, r.Siz, r.Sym.Name)
}
}
}
sect.Rellen = uint64(Cpos()) - sect.Reloff
}
func Elfemitreloc() {
for Cpos()&7 != 0 {
Cput(0)
}
elfrelocsect(Segtext.Sect, Ctxt.Textp)
for sect := Segtext.Sect.Next; sect != nil; sect = sect.Next {
elfrelocsect(sect, datap)
}
for sect := Segrodata.Sect; sect != nil; sect = sect.Next {
elfrelocsect(sect, datap)
}
for sect := Segdata.Sect; sect != nil; sect = sect.Next {
elfrelocsect(sect, datap)
}
}
func addgonote(sectionName string, tag uint32, desc []byte) {
s := Linklookup(Ctxt, sectionName, 0)
s.Reachable = true
s.Type = obj.SELFROSECT
// namesz
Adduint32(Ctxt, s, uint32(len(ELF_NOTE_GO_NAME)))
// descsz
Adduint32(Ctxt, s, uint32(len(desc)))
// tag
Adduint32(Ctxt, s, tag)
// name + padding
s.P = append(s.P, ELF_NOTE_GO_NAME...)
for len(s.P)%4 != 0 {
s.P = append(s.P, 0)
}
// desc + padding
s.P = append(s.P, desc...)
for len(s.P)%4 != 0 {
s.P = append(s.P, 0)
}
s.Size = int64(len(s.P))
}
func doelf() {
if !Iself {
return
}
/* predefine strings we need for section headers */
shstrtab := Linklookup(Ctxt, ".shstrtab", 0)
shstrtab.Type = obj.SELFROSECT
shstrtab.Reachable = true
Addstring(shstrtab, "")
Addstring(shstrtab, ".text")
Addstring(shstrtab, ".noptrdata")
Addstring(shstrtab, ".data")
Addstring(shstrtab, ".bss")
Addstring(shstrtab, ".noptrbss")
// generate .tbss section (except for OpenBSD where it's not supported)
// for dynamic internal linker or external linking, so that various
// binutils could correctly calculate PT_TLS size.
// see https://golang.org/issue/5200.
if HEADTYPE != obj.Hopenbsd {
if Debug['d'] == 0 || Linkmode == LinkExternal {
Addstring(shstrtab, ".tbss")
}
}
if HEADTYPE == obj.Hnetbsd {
Addstring(shstrtab, ".note.netbsd.ident")
}
if HEADTYPE == obj.Hopenbsd {
Addstring(shstrtab, ".note.openbsd.ident")
}
if len(buildinfo) > 0 {
Addstring(shstrtab, ".note.gnu.build-id")
}
if buildid != "" {
Addstring(shstrtab, ".note.go.buildid")
}
Addstring(shstrtab, ".elfdata")
Addstring(shstrtab, ".rodata")
Addstring(shstrtab, ".typelink")
Addstring(shstrtab, ".gosymtab")
Addstring(shstrtab, ".gopclntab")
if Linkmode == LinkExternal {
Debug['d'] = 1
switch Thearch.Thechar {
case '6', '7', '9':
Addstring(shstrtab, ".rela.text")
Addstring(shstrtab, ".rela.rodata")
Addstring(shstrtab, ".rela.typelink")
Addstring(shstrtab, ".rela.gosymtab")
Addstring(shstrtab, ".rela.gopclntab")
Addstring(shstrtab, ".rela.noptrdata")
Addstring(shstrtab, ".rela.data")
default:
Addstring(shstrtab, ".rel.text")
Addstring(shstrtab, ".rel.rodata")
Addstring(shstrtab, ".rel.typelink")
Addstring(shstrtab, ".rel.gosymtab")
Addstring(shstrtab, ".rel.gopclntab")
Addstring(shstrtab, ".rel.noptrdata")
Addstring(shstrtab, ".rel.data")
}
// add a .note.GNU-stack section to mark the stack as non-executable
Addstring(shstrtab, ".note.GNU-stack")
if Buildmode == BuildmodeShared {
Addstring(shstrtab, ".note.go.abihash")
Addstring(shstrtab, ".note.go.pkg-list")
Addstring(shstrtab, ".note.go.deps")
}
if buildid != "" {
Addstring(shstrtab, ".note.go.buildid")
}
}
hasinitarr := Linkshared
/* shared library initializer */
switch Buildmode {
case BuildmodeCArchive, BuildmodeCShared, BuildmodeShared:
hasinitarr = true
}
if hasinitarr {
Addstring(shstrtab, ".init_array")
switch Thearch.Thechar {
case '6', '7', '9':
Addstring(shstrtab, ".rela.init_array")
default:
Addstring(shstrtab, ".rel.init_array")
}
}
if Debug['s'] == 0 {
Addstring(shstrtab, ".symtab")
Addstring(shstrtab, ".strtab")
dwarfaddshstrings(shstrtab)
}
Addstring(shstrtab, ".shstrtab")
if Debug['d'] == 0 { /* -d suppresses dynamic loader format */
Addstring(shstrtab, ".interp")
Addstring(shstrtab, ".hash")
Addstring(shstrtab, ".got")
if Thearch.Thechar == '9' {
Addstring(shstrtab, ".glink")
}
Addstring(shstrtab, ".got.plt")
Addstring(shstrtab, ".dynamic")
Addstring(shstrtab, ".dynsym")
Addstring(shstrtab, ".dynstr")
switch Thearch.Thechar {
case '6', '7', '9':
Addstring(shstrtab, ".rela")
Addstring(shstrtab, ".rela.plt")
default:
Addstring(shstrtab, ".rel")
Addstring(shstrtab, ".rel.plt")
}
Addstring(shstrtab, ".plt")
Addstring(shstrtab, ".gnu.version")
Addstring(shstrtab, ".gnu.version_r")
/* dynamic symbol table - first entry all zeros */
s := Linklookup(Ctxt, ".dynsym", 0)
s.Type = obj.SELFROSECT
s.Reachable = true
switch Thearch.Thechar {
case '6', '7', '9':
s.Size += ELF64SYMSIZE
default:
s.Size += ELF32SYMSIZE
}
/* dynamic string table */
s = Linklookup(Ctxt, ".dynstr", 0)
s.Type = obj.SELFROSECT
s.Reachable = true
if s.Size == 0 {
Addstring(s, "")
}
dynstr := s
/* relocation table */
switch Thearch.Thechar {
case '6', '7', '9':
s = Linklookup(Ctxt, ".rela", 0)
default:
s = Linklookup(Ctxt, ".rel", 0)
}
s.Reachable = true
s.Type = obj.SELFROSECT
/* global offset table */
s = Linklookup(Ctxt, ".got", 0)
s.Reachable = true
s.Type = obj.SELFGOT // writable
/* ppc64 glink resolver */
if Thearch.Thechar == '9' {
s := Linklookup(Ctxt, ".glink", 0)
s.Reachable = true
s.Type = obj.SELFRXSECT
}
/* hash */
s = Linklookup(Ctxt, ".hash", 0)
s.Reachable = true
s.Type = obj.SELFROSECT
s = Linklookup(Ctxt, ".got.plt", 0)
s.Reachable = true
s.Type = obj.SELFSECT // writable
s = Linklookup(Ctxt, ".plt", 0)
s.Reachable = true
if Thearch.Thechar == '9' {
// In the ppc64 ABI, .plt is a data section
// written by the dynamic linker.
s.Type = obj.SELFSECT
} else {
s.Type = obj.SELFRXSECT
}
Thearch.Elfsetupplt()
switch Thearch.Thechar {
case '6', '7', '9':
s = Linklookup(Ctxt, ".rela.plt", 0)
default:
s = Linklookup(Ctxt, ".rel.plt", 0)
}
s.Reachable = true
s.Type = obj.SELFROSECT
s = Linklookup(Ctxt, ".gnu.version", 0)
s.Reachable = true
s.Type = obj.SELFROSECT
s = Linklookup(Ctxt, ".gnu.version_r", 0)
s.Reachable = true
s.Type = obj.SELFROSECT
/* define dynamic elf table */
s = Linklookup(Ctxt, ".dynamic", 0)
s.Reachable = true
s.Type = obj.SELFSECT // writable
/*
* .dynamic table
*/
elfwritedynentsym(s, DT_HASH, Linklookup(Ctxt, ".hash", 0))
elfwritedynentsym(s, DT_SYMTAB, Linklookup(Ctxt, ".dynsym", 0))
switch Thearch.Thechar {
case '6', '7', '9':
Elfwritedynent(s, DT_SYMENT, ELF64SYMSIZE)
default:
Elfwritedynent(s, DT_SYMENT, ELF32SYMSIZE)
}
elfwritedynentsym(s, DT_STRTAB, Linklookup(Ctxt, ".dynstr", 0))
elfwritedynentsymsize(s, DT_STRSZ, Linklookup(Ctxt, ".dynstr", 0))
switch Thearch.Thechar {
case '6', '7', '9':
elfwritedynentsym(s, DT_RELA, Linklookup(Ctxt, ".rela", 0))
elfwritedynentsymsize(s, DT_RELASZ, Linklookup(Ctxt, ".rela", 0))
Elfwritedynent(s, DT_RELAENT, ELF64RELASIZE)
default:
elfwritedynentsym(s, DT_REL, Linklookup(Ctxt, ".rel", 0))
elfwritedynentsymsize(s, DT_RELSZ, Linklookup(Ctxt, ".rel", 0))
Elfwritedynent(s, DT_RELENT, ELF32RELSIZE)
}
if rpath.val != "" {
Elfwritedynent(s, DT_RUNPATH, uint64(Addstring(dynstr, rpath.val)))
}
if Thearch.Thechar == '9' {
elfwritedynentsym(s, DT_PLTGOT, Linklookup(Ctxt, ".plt", 0))
} else {
elfwritedynentsym(s, DT_PLTGOT, Linklookup(Ctxt, ".got.plt", 0))
}
if Thearch.Thechar == '9' {
Elfwritedynent(s, 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(s, DT_DEBUG, 0)
}
if Buildmode == BuildmodeShared {
// The go.link.abihashbytes symbol will be pointed at the appropriate
// part of the .note.go.abihash section in data.go:func address().
s := Linklookup(Ctxt, "go.link.abihashbytes", 0)
s.Local = true
s.Type = obj.SRODATA
s.Special = 1
s.Reachable = true
s.Size = int64(sha1.Size)
sort.Sort(byPkg(Ctxt.Library))
h := sha1.New()
for _, l := range Ctxt.Library {
h.Write(l.hash)
}
addgonote(".note.go.abihash", ELF_NOTE_GOABIHASH_TAG, h.Sum([]byte{}))
addgonote(".note.go.pkg-list", ELF_NOTE_GOPKGLIST_TAG, []byte(pkglistfornote))
var deplist []string
for _, shlib := range Ctxt.Shlibs {
deplist = append(deplist, filepath.Base(shlib.Path))
}
addgonote(".note.go.deps", ELF_NOTE_GODEPS_TAG, []byte(strings.Join(deplist, "\n")))
}
if Linkmode == LinkExternal && buildid != "" {
addgonote(".note.go.buildid", ELF_NOTE_GOBUILDID_TAG, []byte(buildid))
}
}
// Do not write DT_NULL. elfdynhash will finish it.
func shsym(sh *ElfShdr, s *LSym) {
addr := Symaddr(s)
if sh.flags&SHF_ALLOC != 0 {
sh.addr = uint64(addr)
}
sh.off = uint64(datoff(addr))
sh.size = uint64(s.Size)
}
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 := Segtext.Sect; sect != nil; sect = sect.Next {
elfshalloc(sect)
}
for sect := Segrodata.Sect; sect != nil; sect = sect.Next {
elfshalloc(sect)
}
for sect := Segdata.Sect; sect != nil; sect = sect.Next {
elfshalloc(sect)
}
}
func Asmbelf(symo int64) {
eh := getElfEhdr()
switch Thearch.Thechar {
default:
Exitf("unknown architecture in asmbelf: %v", Thearch.Thechar)
case '5':
eh.machine = EM_ARM
case '6':
eh.machine = EM_X86_64
case '7':
eh.machine = EM_AARCH64
case '8':
eh.machine = EM_386
case '9':
eh.machine = EM_PPC64
}
elfreserve := int64(ELFRESERVE)
startva := INITTEXT - int64(HEADR)
resoff := elfreserve
var pph *ElfPhdr
var pnote *ElfPhdr
if Linkmode == LinkExternal {
/* skip program headers */
eh.phoff = 0
eh.phentsize = 0
if 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 buildid != "" {
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(INITTEXT) - uint64(HEADR) + pph.off
pph.paddr = uint64(INITTEXT) - uint64(HEADR) + pph.off
pph.align = uint64(INITRND)
/*
* PHDR must be in a loaded segment. Adjust the text
* segment boundaries downwards to include it.
* Except on NaCl where it must not be loaded.
*/
if HEADTYPE != obj.Hnacl {
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 Debug['d'] == 0 { /* -d suppresses dynamic loader format */
/* interpreter */
sh := elfshname(".interp")
sh.type_ = SHT_PROGBITS
sh.flags = SHF_ALLOC
sh.addralign = 1
if interpreter == "" {
switch HEADTYPE {
case obj.Hlinux:
interpreter = Thearch.Linuxdynld
case obj.Hfreebsd:
interpreter = Thearch.Freebsddynld
case obj.Hnetbsd:
interpreter = Thearch.Netbsddynld
case obj.Hopenbsd:
interpreter = Thearch.Openbsddynld
case obj.Hdragonfly:
interpreter = Thearch.Dragonflydynld
case obj.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 HEADTYPE == obj.Hnetbsd || HEADTYPE == obj.Hopenbsd {
var sh *ElfShdr
switch HEADTYPE {
case obj.Hnetbsd:
sh = elfshname(".note.netbsd.ident")
resoff -= int64(elfnetbsdsig(sh, uint64(startva), uint64(resoff)))
case obj.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 buildid != "" {
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 Segrodata.Sect != nil {
elfphload(&Segrodata)
}
elfphload(&Segdata)
/* Dynamic linking sections */
if Debug['d'] == 0 {
sh := elfshname(".dynsym")
sh.type_ = SHT_DYNSYM
sh.flags = SHF_ALLOC
if elf64 {
sh.entsize = ELF64SYMSIZE
} else {
sh.entsize = ELF32SYMSIZE
}
sh.addralign = uint64(Thearch.Regsize)
sh.link = uint32(elfshname(".dynstr").shnum)
// sh->info = index of first non-local symbol (number of local symbols)
shsym(sh, Linklookup(Ctxt, ".dynsym", 0))
sh = elfshname(".dynstr")
sh.type_ = SHT_STRTAB
sh.flags = SHF_ALLOC
sh.addralign = 1
shsym(sh, Linklookup(Ctxt, ".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, Linklookup(Ctxt, ".gnu.version", 0))
sh = elfshname(".gnu.version_r")
sh.type_ = SHT_GNU_VERNEED
sh.flags = SHF_ALLOC
sh.addralign = uint64(Thearch.Regsize)
sh.info = uint32(elfverneed)
sh.link = uint32(elfshname(".dynstr").shnum)
shsym(sh, Linklookup(Ctxt, ".gnu.version_r", 0))
}
switch eh.machine {
case EM_X86_64, EM_PPC64, EM_AARCH64:
sh := elfshname(".rela.plt")
sh.type_ = SHT_RELA
sh.flags = SHF_ALLOC
sh.entsize = ELF64RELASIZE
sh.addralign = uint64(Thearch.Regsize)
sh.link = uint32(elfshname(".dynsym").shnum)
sh.info = uint32(elfshname(".plt").shnum)
shsym(sh, Linklookup(Ctxt, ".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, Linklookup(Ctxt, ".rela", 0))
default:
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, Linklookup(Ctxt, ".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, Linklookup(Ctxt, ".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, Linklookup(Ctxt, ".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_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, Linklookup(Ctxt, ".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(Thearch.Regsize)
sh.addralign = uint64(Thearch.Regsize)
shsym(sh, Linklookup(Ctxt, ".got", 0))
sh = elfshname(".got.plt")
sh.type_ = SHT_PROGBITS
sh.flags = SHF_ALLOC + SHF_WRITE
sh.entsize = uint64(Thearch.Regsize)
sh.addralign = uint64(Thearch.Regsize)
shsym(sh, Linklookup(Ctxt, ".got.plt", 0))
}
sh = elfshname(".hash")
sh.type_ = SHT_HASH
sh.flags = SHF_ALLOC
sh.entsize = 4
sh.addralign = uint64(Thearch.Regsize)
sh.link = uint32(elfshname(".dynsym").shnum)
shsym(sh, Linklookup(Ctxt, ".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(Thearch.Regsize)
sh.addralign = uint64(Thearch.Regsize)
sh.link = uint32(elfshname(".dynstr").shnum)
shsym(sh, Linklookup(Ctxt, ".dynamic", 0))
ph := newElfPhdr()
ph.type_ = PT_DYNAMIC
ph.flags = PF_R + PF_W
phsh(ph, sh)
/*
* Thread-local storage segment (really just size).
*/
// Do not emit PT_TLS for OpenBSD since ld.so(1) does
// not currently support it. This is handled
// appropriately in runtime/cgo.
if Ctxt.Tlsoffset != 0 && HEADTYPE != obj.Hopenbsd {
ph := newElfPhdr()
ph.type_ = PT_TLS
ph.flags = PF_R
ph.memsz = uint64(-Ctxt.Tlsoffset)
ph.align = uint64(Thearch.Regsize)
}
}
if HEADTYPE == obj.Hlinux {
ph := newElfPhdr()
ph.type_ = PT_GNU_STACK
ph.flags = PF_W + PF_R
ph.align = uint64(Thearch.Regsize)
ph = newElfPhdr()
ph.type_ = PT_PAX_FLAGS
ph.flags = 0x2a00 // mprotect, randexec, emutramp disabled
ph.align = uint64(Thearch.Regsize)
}
elfobj:
sh := elfshname(".shstrtab")
sh.type_ = SHT_STRTAB
sh.addralign = 1
shsym(sh, Linklookup(Ctxt, ".shstrtab", 0))
eh.shstrndx = uint16(sh.shnum)
// put these sections early in the list
if Debug['s'] == 0 {
elfshname(".symtab")
elfshname(".strtab")
}
for sect := Segtext.Sect; sect != nil; sect = sect.Next {
elfshbits(sect)
}
for sect := Segrodata.Sect; sect != nil; sect = sect.Next {
elfshbits(sect)
}
for sect := Segdata.Sect; sect != nil; sect = sect.Next {
elfshbits(sect)
}
if Linkmode == LinkExternal {
for sect := Segtext.Sect; sect != nil; sect = sect.Next {
elfshreloc(sect)
}
for sect := Segrodata.Sect; sect != nil; sect = sect.Next {
elfshreloc(sect)
}
for sect := Segdata.Sect; sect != nil; sect = sect.Next {
elfshreloc(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
}
// generate .tbss section for dynamic internal linking (except for OpenBSD)
// external linking generates .tbss in data.c
if Linkmode == LinkInternal && Debug['d'] == 0 && HEADTYPE != obj.Hopenbsd {
sh := elfshname(".tbss")
sh.type_ = SHT_NOBITS
sh.addralign = uint64(Thearch.Regsize)
sh.size = uint64(-Ctxt.Tlsoffset)
sh.flags = SHF_ALLOC | SHF_TLS | SHF_WRITE
}
if Debug['s'] == 0 {
sh := elfshname(".symtab")
sh.type_ = SHT_SYMTAB
sh.off = uint64(symo)
sh.size = uint64(Symsize)
sh.addralign = uint64(Thearch.Regsize)
sh.entsize = 8 + 2*uint64(Thearch.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
dwarfaddelfheaders()
}
/* Main header */
eh.ident[EI_MAG0] = '\177'
eh.ident[EI_MAG1] = 'E'
eh.ident[EI_MAG2] = 'L'
eh.ident[EI_MAG3] = 'F'
if HEADTYPE == obj.Hfreebsd {
eh.ident[EI_OSABI] = ELFOSABI_FREEBSD
} else if HEADTYPE == obj.Hnetbsd {
eh.ident[EI_OSABI] = ELFOSABI_NETBSD
} else if HEADTYPE == obj.Hopenbsd {
eh.ident[EI_OSABI] = ELFOSABI_OPENBSD
} else if HEADTYPE == obj.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 Linkmode == LinkExternal {
eh.type_ = ET_REL
} else {
eh.type_ = ET_EXEC
}
if Linkmode != LinkExternal {
eh.entry = uint64(Entryvalue())
}
eh.version = EV_CURRENT
if pph != nil {
pph.filesz = uint64(eh.phnum) * uint64(eh.phentsize)
pph.memsz = pph.filesz
}
Cseek(0)
a := int64(0)
a += int64(elfwritehdr())
a += int64(elfwritephdrs())
a += int64(elfwriteshdrs())
if Debug['d'] == 0 {
a += int64(elfwriteinterp())
}
if Linkmode != LinkExternal {
if HEADTYPE == obj.Hnetbsd {
a += int64(elfwritenetbsdsig())
}
if HEADTYPE == obj.Hopenbsd {
a += int64(elfwriteopenbsdsig())
}
if len(buildinfo) > 0 {
a += int64(elfwritebuildinfo())
}
if buildid != "" {
a += int64(elfwritegobuildid())
}
}
if a > elfreserve {
Diag("ELFRESERVE too small: %d > %d", a, elfreserve)
}
}
func Elfadddynsym(ctxt *Link, s *LSym) {
if elf64 {
s.Dynid = int32(Nelfsym)
Nelfsym++
d := Linklookup(ctxt, ".dynsym", 0)
name := s.Extname
Adduint32(ctxt, d, uint32(Addstring(Linklookup(ctxt, ".dynstr", 0), name)))
/* type */
t := STB_GLOBAL << 4
if s.Cgoexport != 0 && s.Type&obj.SMASK == obj.STEXT {
t |= STT_FUNC
} else {
t |= STT_OBJECT
}
Adduint8(ctxt, d, uint8(t))
/* reserved */
Adduint8(ctxt, d, 0)
/* section where symbol is defined */
if s.Type == obj.SDYNIMPORT {
Adduint16(ctxt, d, SHN_UNDEF)
} else {
Adduint16(ctxt, d, 1)
}
/* value */
if s.Type == obj.SDYNIMPORT {
Adduint64(ctxt, d, 0)
} else {
Addaddr(ctxt, d, s)
}
/* size of object */
Adduint64(ctxt, d, uint64(s.Size))
if Thearch.Thechar == '6' && s.Cgoexport&CgoExportDynamic == 0 && s.Dynimplib != "" && !seenlib[s.Dynimplib] {
Elfwritedynent(Linklookup(ctxt, ".dynamic", 0), DT_NEEDED, uint64(Addstring(Linklookup(ctxt, ".dynstr", 0), s.Dynimplib)))
}
} else {
s.Dynid = int32(Nelfsym)
Nelfsym++
d := Linklookup(ctxt, ".dynsym", 0)
/* name */
name := s.Extname
Adduint32(ctxt, d, uint32(Addstring(Linklookup(ctxt, ".dynstr", 0), name)))
/* value */
if s.Type == obj.SDYNIMPORT {
Adduint32(ctxt, d, 0)
} else {
Addaddr(ctxt, d, s)
}
/* size */
Adduint32(ctxt, d, 0)
/* type */
t := STB_GLOBAL << 4
// TODO(mwhudson): presumably the behaviour should actually be the same on both arm and 386.
if Thearch.Thechar == '8' && s.Cgoexport != 0 && s.Type&obj.SMASK == obj.STEXT {
t |= STT_FUNC
} else if Thearch.Thechar == '5' && s.Cgoexport&CgoExportDynamic != 0 && s.Type&obj.SMASK == obj.STEXT {
t |= STT_FUNC
} else {
t |= STT_OBJECT
}
Adduint8(ctxt, d, uint8(t))
Adduint8(ctxt, d, 0)
/* shndx */
if s.Type == obj.SDYNIMPORT {
Adduint16(ctxt, d, SHN_UNDEF)
} else {
Adduint16(ctxt, d, 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
}