func elfsetupplt() { plt := ld.Linklookup(ld.Ctxt, ".plt", 0) got := ld.Linklookup(ld.Ctxt, ".got.plt", 0) if plt.Size == 0 { // pushl got+4 ld.Adduint8(ld.Ctxt, plt, 0xff) ld.Adduint8(ld.Ctxt, plt, 0x35) ld.Addaddrplus(ld.Ctxt, plt, got, 4) // jmp *got+8 ld.Adduint8(ld.Ctxt, plt, 0xff) ld.Adduint8(ld.Ctxt, plt, 0x25) ld.Addaddrplus(ld.Ctxt, plt, got, 8) // zero pad ld.Adduint32(ld.Ctxt, plt, 0) // assume got->size == 0 too ld.Addaddrplus(ld.Ctxt, got, ld.Linklookup(ld.Ctxt, ".dynamic", 0), 0) ld.Adduint32(ld.Ctxt, got, 0) ld.Adduint32(ld.Ctxt, got, 0) } }
func elfsetupplt() { plt := ld.Linklookup(ld.Ctxt, ".plt", 0) got := ld.Linklookup(ld.Ctxt, ".got.plt", 0) if plt.Size == 0 { // pushq got+8(IP) ld.Adduint8(ld.Ctxt, plt, 0xff) ld.Adduint8(ld.Ctxt, plt, 0x35) ld.Addpcrelplus(ld.Ctxt, plt, got, 8) // jmpq got+16(IP) ld.Adduint8(ld.Ctxt, plt, 0xff) ld.Adduint8(ld.Ctxt, plt, 0x25) ld.Addpcrelplus(ld.Ctxt, plt, got, 16) // nopl 0(AX) ld.Adduint32(ld.Ctxt, plt, 0x00401f0f) // assume got->size == 0 too ld.Addaddrplus(ld.Ctxt, got, ld.Linklookup(ld.Ctxt, ".dynamic", 0), 0) ld.Adduint64(ld.Ctxt, got, 0) ld.Adduint64(ld.Ctxt, got, 0) } }
func adddynsym(ctxt *ld.Link, s *ld.LSym) { if s.Dynid >= 0 { return } if ld.Iself { s.Dynid = int32(ld.Nelfsym) ld.Nelfsym++ d := ld.Linklookup(ctxt, ".dynsym", 0) name := s.Extname ld.Adduint32(ctxt, d, uint32(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), name))) /* type */ t := ld.STB_GLOBAL << 4 if s.Cgoexport != 0 && s.Type&ld.SMASK == ld.STEXT { t |= ld.STT_FUNC } else { t |= ld.STT_OBJECT } ld.Adduint8(ctxt, d, uint8(t)) /* reserved */ ld.Adduint8(ctxt, d, 0) /* section where symbol is defined */ if s.Type == ld.SDYNIMPORT { ld.Adduint16(ctxt, d, ld.SHN_UNDEF) } else { ld.Adduint16(ctxt, d, 1) } /* value */ if s.Type == ld.SDYNIMPORT { ld.Adduint64(ctxt, d, 0) } else { ld.Addaddr(ctxt, d, s) } /* size of object */ ld.Adduint64(ctxt, d, uint64(s.Size)) if s.Cgoexport&ld.CgoExportDynamic == 0 && s.Dynimplib != "" && needlib(s.Dynimplib) != 0 { ld.Elfwritedynent(ld.Linklookup(ctxt, ".dynamic", 0), ld.DT_NEEDED, uint64(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), s.Dynimplib))) } } else if ld.HEADTYPE == ld.Hdarwin { ld.Diag("adddynsym: missed symbol %s (%s)", s.Name, s.Extname) } else if ld.HEADTYPE == ld.Hwindows { } else // already taken care of { ld.Diag("adddynsym: unsupported binary format") } }
func adddynsym(ctxt *ld.Link, s *ld.LSym) { if s.Dynid >= 0 { return } if ld.Iself { s.Dynid = int32(ld.Nelfsym) ld.Nelfsym++ d := ld.Linklookup(ctxt, ".dynsym", 0) /* name */ name := s.Extname ld.Adduint32(ctxt, d, uint32(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), name))) /* value */ if s.Type == ld.SDYNIMPORT { ld.Adduint32(ctxt, d, 0) } else { ld.Addaddr(ctxt, d, s) } /* size */ ld.Adduint32(ctxt, d, 0) /* type */ t := ld.STB_GLOBAL << 4 if s.Cgoexport != 0 && s.Type&ld.SMASK == ld.STEXT { t |= ld.STT_FUNC } else { t |= ld.STT_OBJECT } ld.Adduint8(ctxt, d, uint8(t)) ld.Adduint8(ctxt, d, 0) /* shndx */ if s.Type == ld.SDYNIMPORT { ld.Adduint16(ctxt, d, ld.SHN_UNDEF) } else { ld.Adduint16(ctxt, d, 1) } } else if ld.HEADTYPE == ld.Hdarwin { ld.Diag("adddynsym: missed symbol %s (%s)", s.Name, s.Extname) } else if ld.HEADTYPE == ld.Hwindows { } else // already taken care of { ld.Diag("adddynsym: unsupported binary format") } }
func adddynsym(ctxt *ld.Link, s *ld.LSym) { if s.Dynid >= 0 { return } if ld.Iself { s.Dynid = int32(ld.Nelfsym) ld.Nelfsym++ d := ld.Linklookup(ctxt, ".dynsym", 0) /* name */ name := s.Extname ld.Adduint32(ctxt, d, uint32(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), name))) /* value */ if s.Type == ld.SDYNIMPORT { ld.Adduint32(ctxt, d, 0) } else { ld.Addaddr(ctxt, d, s) } /* size */ ld.Adduint32(ctxt, d, 0) /* type */ t := ld.STB_GLOBAL << 4 if (s.Cgoexport&ld.CgoExportDynamic != 0) && s.Type&ld.SMASK == ld.STEXT { t |= ld.STT_FUNC } else { t |= ld.STT_OBJECT } ld.Adduint8(ctxt, d, uint8(t)) ld.Adduint8(ctxt, d, 0) /* shndx */ if s.Type == ld.SDYNIMPORT { ld.Adduint16(ctxt, d, ld.SHN_UNDEF) } else { ld.Adduint16(ctxt, d, 1) } } else { ld.Diag("adddynsym: unsupported binary format") } }
func adddynsym(ctxt *ld.Link, s *ld.LSym) { if s.Dynid >= 0 { return } if ld.Iself { s.Dynid = int32(ld.Nelfsym) ld.Nelfsym++ d := ld.Linklookup(ctxt, ".dynsym", 0) name := s.Extname ld.Adduint32(ctxt, d, uint32(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), name))) /* type */ t := ld.STB_GLOBAL << 4 if s.Cgoexport != 0 && s.Type&ld.SMASK == ld.STEXT { t |= ld.STT_FUNC } else { t |= ld.STT_OBJECT } ld.Adduint8(ctxt, d, uint8(t)) /* reserved */ ld.Adduint8(ctxt, d, 0) /* section where symbol is defined */ if s.Type == ld.SDYNIMPORT { ld.Adduint16(ctxt, d, ld.SHN_UNDEF) } else { ld.Adduint16(ctxt, d, 1) } /* value */ if s.Type == ld.SDYNIMPORT { ld.Adduint64(ctxt, d, 0) } else { ld.Addaddr(ctxt, d, s) } /* size of object */ ld.Adduint64(ctxt, d, uint64(s.Size)) } else { ld.Diag("adddynsym: unsupported binary format") } }
func addpltsym(ctxt *ld.Link, s *ld.LSym) { if s.Plt >= 0 { return } adddynsym(ctxt, s) if ld.Iself { plt := ld.Linklookup(ctxt, ".plt", 0) got := ld.Linklookup(ctxt, ".got.plt", 0) rel := ld.Linklookup(ctxt, ".rel.plt", 0) if plt.Size == 0 { elfsetupplt() } // jmpq *got+size ld.Adduint8(ctxt, plt, 0xff) ld.Adduint8(ctxt, plt, 0x25) ld.Addaddrplus(ctxt, plt, got, got.Size) // add to got: pointer to current pos in plt ld.Addaddrplus(ctxt, got, plt, plt.Size) // pushl $x ld.Adduint8(ctxt, plt, 0x68) ld.Adduint32(ctxt, plt, uint32(rel.Size)) // jmp .plt ld.Adduint8(ctxt, plt, 0xe9) ld.Adduint32(ctxt, plt, uint32(-(plt.Size + 4))) // rel ld.Addaddrplus(ctxt, rel, got, got.Size-4) ld.Adduint32(ctxt, rel, ld.ELF32_R_INFO(uint32(s.Dynid), ld.R_386_JMP_SLOT)) s.Plt = int32(plt.Size - 16) } else if ld.HEADTYPE == ld.Hdarwin { // Same laziness as in 6l. plt := ld.Linklookup(ctxt, ".plt", 0) addgotsym(ctxt, s) ld.Adduint32(ctxt, ld.Linklookup(ctxt, ".linkedit.plt", 0), uint32(s.Dynid)) // jmpq *got+size(IP) s.Plt = int32(plt.Size) ld.Adduint8(ctxt, plt, 0xff) ld.Adduint8(ctxt, plt, 0x25) ld.Addaddrplus(ctxt, plt, ld.Linklookup(ctxt, ".got", 0), int64(s.Got)) } else { ld.Diag("addpltsym: unsupported binary format") } }
func gentext() { if !ld.DynlinkingGo() { return } addmoduledata := ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0) if addmoduledata.Type == ld.STEXT { // we're linking a module containing the runtime -> no need for // an init function return } addmoduledata.Reachable = true initfunc := ld.Linklookup(ld.Ctxt, "go.link.addmoduledata", 0) initfunc.Type = ld.STEXT initfunc.Local = true initfunc.Reachable = true o := func(op ...uint8) { for _, op1 := range op { ld.Adduint8(ld.Ctxt, initfunc, op1) } } // 0000000000000000 <local.dso_init>: // 0: 48 8d 3d 00 00 00 00 lea 0x0(%rip),%rdi # 7 <local.dso_init+0x7> // 3: R_X86_64_PC32 runtime.firstmoduledata-0x4 o(0x48, 0x8d, 0x3d) ld.Addpcrelplus(ld.Ctxt, initfunc, ld.Linklookup(ld.Ctxt, "runtime.firstmoduledata", 0), 0) // 7: e8 00 00 00 00 callq c <local.dso_init+0xc> // 8: R_X86_64_PLT32 runtime.addmoduledata-0x4 o(0xe8) Addcall(ld.Ctxt, initfunc, addmoduledata) // c: c3 retq o(0xc3) if ld.Ctxt.Etextp != nil { ld.Ctxt.Etextp.Next = initfunc } else { ld.Ctxt.Textp = initfunc } ld.Ctxt.Etextp = initfunc initarray_entry := ld.Linklookup(ld.Ctxt, "go.link.addmoduledatainit", 0) initarray_entry.Reachable = true initarray_entry.Local = true initarray_entry.Type = ld.SINITARR ld.Addaddr(ld.Ctxt, initarray_entry, initfunc) }
func addpltsym(s *ld.LSym) { if s.Plt >= 0 { return } adddynsym(ld.Ctxt, s) if ld.Iself { plt := ld.Linklookup(ld.Ctxt, ".plt", 0) got := ld.Linklookup(ld.Ctxt, ".got.plt", 0) rela := ld.Linklookup(ld.Ctxt, ".rela.plt", 0) if plt.Size == 0 { elfsetupplt() } // jmpq *got+size(IP) ld.Adduint8(ld.Ctxt, plt, 0xff) ld.Adduint8(ld.Ctxt, plt, 0x25) ld.Addpcrelplus(ld.Ctxt, plt, got, got.Size) // add to got: pointer to current pos in plt ld.Addaddrplus(ld.Ctxt, got, plt, plt.Size) // pushq $x ld.Adduint8(ld.Ctxt, plt, 0x68) ld.Adduint32(ld.Ctxt, plt, uint32((got.Size-24-8)/8)) // jmpq .plt ld.Adduint8(ld.Ctxt, plt, 0xe9) ld.Adduint32(ld.Ctxt, plt, uint32(-(plt.Size + 4))) // rela ld.Addaddrplus(ld.Ctxt, rela, got, got.Size-8) ld.Adduint64(ld.Ctxt, rela, ld.ELF64_R_INFO(uint32(s.Dynid), ld.R_X86_64_JMP_SLOT)) ld.Adduint64(ld.Ctxt, rela, 0) s.Plt = int32(plt.Size - 16) } else if ld.HEADTYPE == ld.Hdarwin { // To do lazy symbol lookup right, we're supposed // to tell the dynamic loader which library each // symbol comes from and format the link info // section just so. I'm too lazy (ha!) to do that // so for now we'll just use non-lazy pointers, // which don't need to be told which library to use. // // http://networkpx.blogspot.com/2009/09/about-lcdyldinfoonly-command.html // has details about what we're avoiding. addgotsym(s) plt := ld.Linklookup(ld.Ctxt, ".plt", 0) ld.Adduint32(ld.Ctxt, ld.Linklookup(ld.Ctxt, ".linkedit.plt", 0), uint32(s.Dynid)) // jmpq *got+size(IP) s.Plt = int32(plt.Size) ld.Adduint8(ld.Ctxt, plt, 0xff) ld.Adduint8(ld.Ctxt, plt, 0x25) ld.Addpcrelplus(ld.Ctxt, plt, ld.Linklookup(ld.Ctxt, ".got", 0), int64(s.Got)) } else { ld.Diag("addpltsym: unsupported binary format") } }
func archinit() { // getgoextlinkenabled is based on GO_EXTLINK_ENABLED when // Go was built; see ../../make.bash. if ld.Linkmode == ld.LinkAuto && obj.Getgoextlinkenabled() == "0" { ld.Linkmode = ld.LinkInternal } switch ld.HEADTYPE { default: if ld.Linkmode == ld.LinkAuto { ld.Linkmode = ld.LinkInternal } if ld.Linkmode == ld.LinkExternal && obj.Getgoextlinkenabled() != "1" { log.Fatalf("cannot use -linkmode=external with -H %s", ld.Headstr(int(ld.HEADTYPE))) } case ld.Hlinux, ld.Hfreebsd, ld.Hnacl, ld.Hdarwin: break } switch ld.HEADTYPE { default: ld.Diag("unknown -H option") ld.Errorexit() fallthrough case ld.Hplan9: /* plan 9 */ ld.HEADR = 32 if ld.INITTEXT == -1 { ld.INITTEXT = 4128 } if ld.INITDAT == -1 { ld.INITDAT = 0 } if ld.INITRND == -1 { ld.INITRND = 4096 } case ld.Hlinux, /* arm elf */ ld.Hfreebsd, ld.Hnetbsd, ld.Hopenbsd: ld.Debug['d'] = 0 // with dynamic linking ld.Elfinit() ld.HEADR = ld.ELFRESERVE if ld.INITTEXT == -1 { ld.INITTEXT = 0x10000 + int64(ld.HEADR) } if ld.INITDAT == -1 { ld.INITDAT = 0 } if ld.INITRND == -1 { ld.INITRND = 4096 } case ld.Hnacl: ld.Elfinit() ld.HEADR = 0x10000 ld.Funcalign = 16 if ld.INITTEXT == -1 { ld.INITTEXT = 0x20000 } if ld.INITDAT == -1 { ld.INITDAT = 0 } if ld.INITRND == -1 { ld.INITRND = 0x10000 } case ld.Hdarwin: /* apple MACH */ ld.Debug['w'] = 1 // disable DWARF generataion ld.Machoinit() ld.HEADR = ld.INITIAL_MACHO_HEADR if ld.INITTEXT == -1 { ld.INITTEXT = 4096 + int64(ld.HEADR) } if ld.INITDAT == -1 { ld.INITDAT = 0 } if ld.INITRND == -1 { ld.INITRND = 4096 } } if ld.INITDAT != 0 && ld.INITRND != 0 { fmt.Printf("warning: -D0x%x is ignored because of -R0x%x\n", uint64(ld.INITDAT), uint32(ld.INITRND)) } // embed goarm to runtime.goarm s := ld.Linklookup(ld.Ctxt, "runtime.goarm", 0) s.Type = ld.SRODATA ld.Adduint8(ld.Ctxt, s, uint8(ld.Ctxt.Goarm)) }