| // 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" |
| "io" |
| "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(s *sym.Symbol, str string, off int) { |
| if nelfstr >= len(elfstr) { |
| 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 elfWriteDynEnt(arch *sys.Arch, s *sym.Symbol, 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(arch *sys.Arch, s *sym.Symbol, tag int, t *sym.Symbol) { |
| Elfwritedynentsymplus(arch, s, tag, t, 0) |
| } |
| |
| func Elfwritedynentsymplus(arch *sys.Arch, s *sym.Symbol, tag int, t *sym.Symbol, add int64) { |
| if elf64 { |
| s.AddUint64(arch, uint64(tag)) |
| } else { |
| s.AddUint32(arch, uint32(tag)) |
| } |
| s.AddAddrPlus(arch, t, add) |
| } |
| |
| func elfWriteDynEntSymSize(arch *sys.Arch, s *sym.Symbol, tag int, t *sym.Symbol) { |
| if elf64 { |
| s.AddUint64(arch, uint64(tag)) |
| } else { |
| s.AddUint32(arch, uint32(tag)) |
| } |
| s.AddSize(arch, t) |
| } |
| |
| // temporary |
| func Elfwritedynent2(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 elfwritedynentsym2(ctxt *Link, s *loader.SymbolBuilder, tag int, t loader.Sym) { |
| Elfwritedynentsymplus2(ctxt, s, tag, t, 0) |
| } |
| |
| func Elfwritedynentsymplus2(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 elfwritedynentsymsize2(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) |
| } |
| |
| // 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 |
| s := ctxt.Syms.Lookup(".hash", 0) |
| s.Type = sym.SELFROSECT |
| s.Attr |= sym.AttrReachable |
| |
| 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 ctxt.Syms.Allsym { |
| if sy.Dynid <= 0 { |
| continue |
| } |
| |
| if sy.Dynimpvers() != "" { |
| need[sy.Dynid] = addelflib(&needlib, sy.Dynimplib(), sy.Dynimpvers()) |
| } |
| |
| name := sy.Extname() |
| hc := elfhash(name) |
| |
| b := hc % uint32(nbucket) |
| chain[sy.Dynid] = buckets[b] |
| buckets[b] = uint32(sy.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]) |
| } |
| } |
| |
| // version symbols |
| dynstr := ctxt.Syms.Lookup(".dynstr", 0) |
| |
| s = ctxt.Syms.Lookup(".gnu.version_r", 0) |
| 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(Addstring(dynstr, 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(Addstring(dynstr, 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 |
| s = ctxt.Syms.Lookup(".gnu.version", 0) |
| |
| 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 = ctxt.Syms.Lookup(".dynamic", 0) |
| elfverneed = nfile |
| if elfverneed != 0 { |
| elfWriteDynEntSym(ctxt.Arch, s, DT_VERNEED, ctxt.Syms.Lookup(".gnu.version_r", 0)) |
| elfWriteDynEnt(ctxt.Arch, s, DT_VERNEEDNUM, uint64(nfile)) |
| elfWriteDynEntSym(ctxt.Arch, s, DT_VERSYM, ctxt.Syms.Lookup(".gnu.version", 0)) |
| } |
| |
| sy := ctxt.Syms.Lookup(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.Arch, s, DT_PLTRELSZ, sy) |
| elfWriteDynEntSym(ctxt.Arch, s, DT_JMPREL, sy) |
| } |
| |
| 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, sect *sym.Section, syms []*sym.Symbol) { |
| // 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(ctxt.Out.Offset()) |
| for i, s := range syms { |
| if !s.Attr.Reachable() { |
| continue |
| } |
| if uint64(s.Value) >= sect.Vaddr { |
| syms = syms[i:] |
| break |
| } |
| } |
| |
| eaddr := int32(sect.Vaddr + sect.Length) |
| for _, s := range syms { |
| if !s.Attr.Reachable() { |
| continue |
| } |
| if s.Value >= int64(eaddr) { |
| break |
| } |
| for ri := range s.R { |
| r := &s.R[ri] |
| if r.Done { |
| continue |
| } |
| if r.Xsym == nil { |
| Errorf(s, "missing xsym in relocation %#v %#v", r.Sym.Name, s) |
| continue |
| } |
| if r.Xsym.ElfsymForReloc() == 0 { |
| Errorf(s, "reloc %d (%s) to non-elf symbol %s (outer=%s) %d (%s)", r.Type, sym.RelocName(ctxt.Arch, r.Type), r.Sym.Name, r.Xsym.Name, r.Sym.Type, r.Sym.Type) |
| } |
| if !r.Xsym.Attr.Reachable() { |
| Errorf(s, "unreachable reloc %d (%s) target %v", r.Type, sym.RelocName(ctxt.Arch, r.Type), r.Xsym.Name) |
| } |
| if !thearch.Elfreloc1(ctxt, r, int64(uint64(s.Value+int64(r.Off))-sect.Vaddr)) { |
| Errorf(s, "unsupported obj reloc %d (%s)/%d to %s", r.Type, sym.RelocName(ctxt.Arch, r.Type), r.Siz, r.Sym.Name) |
| } |
| } |
| } |
| |
| sect.Rellen = uint64(ctxt.Out.Offset()) - sect.Reloff |
| } |
| |
| func Elfemitreloc(ctxt *Link) { |
| for ctxt.Out.Offset()&7 != 0 { |
| ctxt.Out.Write8(0) |
| } |
| |
| for _, sect := range Segtext.Sections { |
| if sect.Name == ".text" { |
| elfrelocsect(ctxt, sect, ctxt.Textp) |
| } else { |
| elfrelocsect(ctxt, sect, ctxt.datap) |
| } |
| } |
| |
| for _, sect := range Segrodata.Sections { |
| elfrelocsect(ctxt, sect, ctxt.datap) |
| } |
| for _, sect := range Segrelrodata.Sections { |
| elfrelocsect(ctxt, sect, ctxt.datap) |
| } |
| for _, sect := range Segdata.Sections { |
| elfrelocsect(ctxt, sect, ctxt.datap) |
| } |
| for _, sect := range Segdwarf.Sections { |
| elfrelocsect(ctxt, sect, dwarfp) |
| } |
| } |
| |
| func addgonote(ctxt *Link, sectionName string, tag uint32, desc []byte) { |
| ldr := ctxt.loader |
| s := ldr.CreateSymForUpdate(sectionName, 0) |
| s.SetReachable(true) |
| 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.SetReachable(true) |
| |
| 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 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) |
| dynsym.SetReachable(true) |
| 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) |
| dynstr.SetReachable(true) |
| if dynstr.Size() == 0 { |
| dynstr.Addstring("") |
| } |
| |
| /* relocation table */ |
| s := ldr.CreateSymForUpdate(elfRelType, 0) |
| s.SetReachable(true) |
| s.SetType(sym.SELFROSECT) |
| |
| /* global offset table */ |
| got := ldr.CreateSymForUpdate(".got", 0) |
| got.SetReachable(true) |
| got.SetType(sym.SELFGOT) // writable |
| |
| /* ppc64 glink resolver */ |
| if ctxt.IsPPC64() { |
| s := ldr.CreateSymForUpdate(".glink", 0) |
| s.SetReachable(true) |
| s.SetType(sym.SELFRXSECT) |
| } |
| |
| /* hash */ |
| hash := ldr.CreateSymForUpdate(".hash", 0) |
| hash.SetReachable(true) |
| hash.SetType(sym.SELFROSECT) |
| |
| gotplt := ldr.CreateSymForUpdate(".got.plt", 0) |
| gotplt.SetReachable(true) |
| gotplt.SetType(sym.SELFSECT) // writable |
| |
| plt := ldr.CreateSymForUpdate(".plt", 0) |
| plt.SetReachable(true) |
| 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.SetReachable(true) |
| s.SetType(sym.SELFROSECT) |
| |
| s = ldr.CreateSymForUpdate(".gnu.version", 0) |
| s.SetReachable(true) |
| s.SetType(sym.SELFROSECT) |
| |
| s = ldr.CreateSymForUpdate(".gnu.version_r", 0) |
| s.SetReachable(true) |
| s.SetType(sym.SELFROSECT) |
| |
| /* define dynamic elf table */ |
| dynamic := ldr.CreateSymForUpdate(".dynamic", 0) |
| dynamic.SetReachable(true) |
| 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 |
| */ |
| elfwritedynentsym2(ctxt, dynamic, DT_HASH, hash.Sym()) |
| |
| elfwritedynentsym2(ctxt, dynamic, DT_SYMTAB, dynsym.Sym()) |
| if elf64 { |
| Elfwritedynent2(ctxt.Arch, dynamic, DT_SYMENT, ELF64SYMSIZE) |
| } else { |
| Elfwritedynent2(ctxt.Arch, dynamic, DT_SYMENT, ELF32SYMSIZE) |
| } |
| elfwritedynentsym2(ctxt, dynamic, DT_STRTAB, dynstr.Sym()) |
| elfwritedynentsymsize2(ctxt, dynamic, DT_STRSZ, dynstr.Sym()) |
| if elfRelType == ".rela" { |
| rela := ldr.LookupOrCreateSym(".rela", 0) |
| elfwritedynentsym2(ctxt, dynamic, DT_RELA, rela) |
| elfwritedynentsymsize2(ctxt, dynamic, DT_RELASZ, rela) |
| Elfwritedynent2(ctxt.Arch, dynamic, DT_RELAENT, ELF64RELASIZE) |
| } else { |
| rel := ldr.LookupOrCreateSym(".rel", 0) |
| elfwritedynentsym2(ctxt, dynamic, DT_REL, rel) |
| elfwritedynentsymsize2(ctxt, dynamic, DT_RELSZ, rel) |
| Elfwritedynent2(ctxt.Arch, dynamic, DT_RELENT, ELF32RELSIZE) |
| } |
| |
| if rpath.val != "" { |
| Elfwritedynent2(ctxt.Arch, dynamic, DT_RUNPATH, uint64(dynstr.Addstring(rpath.val))) |
| } |
| |
| if ctxt.IsPPC64() { |
| elfwritedynentsym2(ctxt, dynamic, DT_PLTGOT, plt.Sym()) |
| } else { |
| elfwritedynentsym2(ctxt, dynamic, DT_PLTGOT, gotplt.Sym()) |
| } |
| |
| if ctxt.IsPPC64() { |
| Elfwritedynent2(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. |
| Elfwritedynent2(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 { |
| io.WriteString(h, l.Hash) |
| } |
| 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, s *sym.Symbol) { |
| addr := Symaddr(s) |
| if sh.flags&SHF_ALLOC != 0 { |
| sh.addr = uint64(addr) |
| } |
| sh.off = uint64(datoff(s, 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 := 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, symo int64) { |
| 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 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 := ctxt.Syms.Lookup(".dynsym", 0) |
| i := uint32(0) |
| for sub := s; sub != nil; sub = sub.Sub { |
| i++ |
| if !sub.Attr.Local() { |
| break |
| } |
| } |
| sh.info = i |
| shsym(sh, s) |
| |
| sh = elfshname(".dynstr") |
| sh.type_ = SHT_STRTAB |
| sh.flags = SHF_ALLOC |
| sh.addralign = 1 |
| shsym(sh, ctxt.Syms.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, ctxt.Syms.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, ctxt.Syms.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, ctxt.Syms.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, ctxt.Syms.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, ctxt.Syms.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, ctxt.Syms.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, ctxt.Syms.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, ctxt.Syms.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, ctxt.Syms.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, ctxt.Syms.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, ctxt.Syms.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, ctxt.Syms.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, ctxt.Syms.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 _, s := range dwarfp { |
| if len(s.R) > 0 || s.Type == sym.SDWARFINFO || s.Type == sym.SDWARFLOC { |
| elfshreloc(ctxt.Arch, s.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 a > elfreserve { |
| Errorf(nil, "ELFRESERVE too small: %d > %d with %d text sections", a, elfreserve, numtext) |
| } |
| } |
| |
| func elfadddynsym(target *Target, syms *ArchSyms, s *sym.Symbol) { |
| if elf64 { |
| s.Dynid = int32(Nelfsym) |
| Nelfsym++ |
| |
| d := syms.DynSym |
| |
| name := s.Extname() |
| d.AddUint32(target.Arch, uint32(Addstring(syms.DynStr, name))) |
| |
| /* type */ |
| t := STB_GLOBAL << 4 |
| |
| if s.Attr.CgoExport() && s.Type == sym.STEXT { |
| t |= STT_FUNC |
| } else { |
| t |= STT_OBJECT |
| } |
| d.AddUint8(uint8(t)) |
| |
| /* reserved */ |
| d.AddUint8(0) |
| |
| /* section where symbol is defined */ |
| if s.Type == sym.SDYNIMPORT { |
| d.AddUint16(target.Arch, SHN_UNDEF) |
| } else { |
| d.AddUint16(target.Arch, 1) |
| } |
| |
| /* value */ |
| if s.Type == sym.SDYNIMPORT { |
| d.AddUint64(target.Arch, 0) |
| } else { |
| d.AddAddr(target.Arch, s) |
| } |
| |
| /* size of object */ |
| d.AddUint64(target.Arch, uint64(s.Size)) |
| |
| if target.Arch.Family == sys.AMD64 && !s.Attr.CgoExportDynamic() && s.Dynimplib() != "" && !seenlib[s.Dynimplib()] { |
| elfWriteDynEnt(target.Arch, syms.Dynamic, DT_NEEDED, uint64(Addstring(syms.DynStr, s.Dynimplib()))) |
| } |
| } else { |
| s.Dynid = int32(Nelfsym) |
| Nelfsym++ |
| |
| d := syms.DynSym |
| |
| /* name */ |
| name := s.Extname() |
| |
| d.AddUint32(target.Arch, uint32(Addstring(syms.DynStr, name))) |
| |
| /* value */ |
| if s.Type == sym.SDYNIMPORT { |
| d.AddUint32(target.Arch, 0) |
| } else { |
| d.AddAddr(target.Arch, s) |
| } |
| |
| /* size of object */ |
| d.AddUint32(target.Arch, uint32(s.Size)) |
| |
| /* 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 && s.Attr.CgoExport() && s.Type == sym.STEXT { |
| t |= STT_FUNC |
| } else if target.Arch.Family == sys.ARM && s.Attr.CgoExportDynamic() && s.Type == sym.STEXT { |
| t |= STT_FUNC |
| } else { |
| t |= STT_OBJECT |
| } |
| d.AddUint8(uint8(t)) |
| d.AddUint8(0) |
| |
| /* shndx */ |
| if s.Type == sym.SDYNIMPORT { |
| d.AddUint16(target.Arch, SHN_UNDEF) |
| } else { |
| d.AddUint16(target.Arch, 1) |
| } |
| } |
| } |
| |
| func elfadddynsym2(ldr *loader.Loader, target *Target, syms *ArchSyms, s loader.Sym) { |
| ldr.SetSymDynid(s, int32(Nelfsym)) |
| Nelfsym++ |
| d := ldr.MakeSymbolUpdater(syms.DynSym2) |
| name := ldr.SymExtname(s) |
| dstru := ldr.MakeSymbolUpdater(syms.DynStr2) |
| 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.Dynamic2) |
| Elfwritedynent2(target.Arch, du, DT_NEEDED, uint64(dstru.Addstring(dil))) |
| } |
| } 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 |
| } |