func LoadObjFile(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
start := f.Offset()
r := &objReader{
rd: f.Reader,
pkg: pkg,
ctxt: ctxt,
pn: pn,
dupSym: &LSym{Name: ".dup"},
}
r.loadObjFile()
if f.Offset() != start+length {
log.Fatalf("%s: unexpected end at %d, want %d", pn, f.Offset(), start+length)
}
}
func ldpe(f *bio.Reader, pkg string, length int64, pn string) {
if Debug['v'] != 0 {
fmt.Fprintf(Bso, "%5.2f ldpe %s\n", obj.Cputime(), pn)
}
var sect *PeSect
Ctxt.IncVersion()
base := f.Offset()
peobj := new(PeObj)
peobj.f = f
peobj.base = uint32(base)
peobj.name = pn
// read header
var err error
var j int
var l uint32
var name string
var numaux int
var r []Reloc
var rp *Reloc
var rsect *PeSect
var s *LSym
var sym *PeSym
var symbuf [18]uint8
if err = binary.Read(f, binary.LittleEndian, &peobj.fh); err != nil {
goto bad
}
// load section list
peobj.sect = make([]PeSect, peobj.fh.NumberOfSections)
peobj.nsect = uint(peobj.fh.NumberOfSections)
for i := 0; i < int(peobj.fh.NumberOfSections); i++ {
if err = binary.Read(f, binary.LittleEndian, &peobj.sect[i].sh); err != nil {
goto bad
}
peobj.sect[i].size = uint64(peobj.sect[i].sh.SizeOfRawData)
peobj.sect[i].name = cstring(peobj.sect[i].sh.Name[:])
}
// TODO return error if found .cormeta
// load string table
f.Seek(base+int64(peobj.fh.PointerToSymbolTable)+int64(len(symbuf))*int64(peobj.fh.NumberOfSymbols), 0)
if _, err := io.ReadFull(f, symbuf[:4]); err != nil {
goto bad
}
l = Le32(symbuf[:])
peobj.snames = make([]byte, l)
f.Seek(base+int64(peobj.fh.PointerToSymbolTable)+int64(len(symbuf))*int64(peobj.fh.NumberOfSymbols), 0)
if _, err := io.ReadFull(f, peobj.snames); err != nil {
goto bad
}
// rewrite section names if they start with /
for i := 0; i < int(peobj.fh.NumberOfSections); i++ {
if peobj.sect[i].name == "" {
continue
}
if peobj.sect[i].name[0] != '/' {
continue
}
n, _ := strconv.Atoi(peobj.sect[i].name[1:])
peobj.sect[i].name = cstring(peobj.snames[n:])
}
// read symbols
peobj.pesym = make([]PeSym, peobj.fh.NumberOfSymbols)
peobj.npesym = uint(peobj.fh.NumberOfSymbols)
f.Seek(base+int64(peobj.fh.PointerToSymbolTable), 0)
for i := 0; uint32(i) < peobj.fh.NumberOfSymbols; i += numaux + 1 {
f.Seek(base+int64(peobj.fh.PointerToSymbolTable)+int64(len(symbuf))*int64(i), 0)
if _, err := io.ReadFull(f, symbuf[:]); err != nil {
goto bad
}
if (symbuf[0] == 0) && (symbuf[1] == 0) && (symbuf[2] == 0) && (symbuf[3] == 0) {
l = Le32(symbuf[4:])
peobj.pesym[i].name = cstring(peobj.snames[l:]) // sym name length <= 8
} else {
peobj.pesym[i].name = cstring(symbuf[:8])
}
peobj.pesym[i].value = Le32(symbuf[8:])
peobj.pesym[i].sectnum = Le16(symbuf[12:])
peobj.pesym[i].sclass = symbuf[16]
peobj.pesym[i].aux = symbuf[17]
peobj.pesym[i].type_ = Le16(symbuf[14:])
numaux = int(peobj.pesym[i].aux)
if numaux < 0 {
numaux = 0
}
}
// create symbols for mapped sections
for i := 0; uint(i) < peobj.nsect; i++ {
sect = &peobj.sect[i]
if sect.sh.Characteristics&IMAGE_SCN_MEM_DISCARDABLE != 0 {
continue
}
if sect.sh.Characteristics&(IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 {
// This has been seen for .idata sections, which we
// want to ignore. See issues 5106 and 5273.
continue
}
if pemap(peobj, sect) < 0 {
goto bad
}
name = fmt.Sprintf("%s(%s)", pkg, sect.name)
s = Linklookup(Ctxt, name, Ctxt.Version)
switch sect.sh.Characteristics & (IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE) {
case IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ: //.rdata
s.Type = obj.SRODATA
case IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE: //.bss
s.Type = obj.SNOPTRBSS
case IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE: //.data
s.Type = obj.SNOPTRDATA
case IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_READ: //.text
s.Type = obj.STEXT
default:
err = fmt.Errorf("unexpected flags %#06x for PE section %s", sect.sh.Characteristics, sect.name)
goto bad
}
s.P = sect.base
s.P = s.P[:sect.size]
s.Size = int64(sect.size)
sect.sym = s
if sect.name == ".rsrc" {
setpersrc(sect.sym)
}
}
// load relocations
for i := 0; uint(i) < peobj.nsect; i++ {
rsect = &peobj.sect[i]
if rsect.sym == nil || rsect.sh.NumberOfRelocations == 0 {
continue
}
if rsect.sh.Characteristics&IMAGE_SCN_MEM_DISCARDABLE != 0 {
continue
}
if sect.sh.Characteristics&(IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 {
// This has been seen for .idata sections, which we
// want to ignore. See issues 5106 and 5273.
continue
}
r = make([]Reloc, rsect.sh.NumberOfRelocations)
f.Seek(int64(peobj.base)+int64(rsect.sh.PointerToRelocations), 0)
for j = 0; j < int(rsect.sh.NumberOfRelocations); j++ {
rp = &r[j]
if _, err := io.ReadFull(f, symbuf[:10]); err != nil {
goto bad
}
rva := Le32(symbuf[0:])
symindex := Le32(symbuf[4:])
type_ := Le16(symbuf[8:])
if err = readpesym(peobj, int(symindex), &sym); err != nil {
goto bad
}
if sym.sym == nil {
err = fmt.Errorf("reloc of invalid sym %s idx=%d type=%d", sym.name, symindex, sym.type_)
goto bad
}
rp.Sym = sym.sym
rp.Siz = 4
rp.Off = int32(rva)
switch type_ {
default:
Diag("%s: unknown relocation type %d;", pn, type_)
fallthrough
case IMAGE_REL_I386_REL32, IMAGE_REL_AMD64_REL32,
IMAGE_REL_AMD64_ADDR32, // R_X86_64_PC32
IMAGE_REL_AMD64_ADDR32NB:
rp.Type = obj.R_PCREL
rp.Add = int64(int32(Le32(rsect.base[rp.Off:])))
case IMAGE_REL_I386_DIR32NB, IMAGE_REL_I386_DIR32:
rp.Type = obj.R_ADDR
// load addend from image
rp.Add = int64(int32(Le32(rsect.base[rp.Off:])))
case IMAGE_REL_AMD64_ADDR64: // R_X86_64_64
rp.Siz = 8
rp.Type = obj.R_ADDR
// load addend from image
rp.Add = int64(Le64(rsect.base[rp.Off:]))
}
// ld -r could generate multiple section symbols for the
// same section but with different values, we have to take
// that into account
if issect(&peobj.pesym[symindex]) {
rp.Add += int64(peobj.pesym[symindex].value)
}
}
sort.Sort(rbyoff(r[:rsect.sh.NumberOfRelocations]))
s = rsect.sym
s.R = r
s.R = s.R[:rsect.sh.NumberOfRelocations]
}
// enter sub-symbols into symbol table.
for i := 0; uint(i) < peobj.npesym; i++ {
if peobj.pesym[i].name == "" {
continue
}
if issect(&peobj.pesym[i]) {
continue
}
if uint(peobj.pesym[i].sectnum) > peobj.nsect {
continue
}
if peobj.pesym[i].sectnum > 0 {
sect = &peobj.sect[peobj.pesym[i].sectnum-1]
if sect.sym == nil {
continue
}
}
if err = readpesym(peobj, i, &sym); err != nil {
goto bad
}
s = sym.sym
if sym.sectnum == 0 { // extern
if s.Type == obj.SDYNIMPORT {
s.Plt = -2 // flag for dynimport in PE object files.
}
if s.Type == obj.SXREF && sym.value > 0 { // global data
s.Type = obj.SNOPTRDATA
s.Size = int64(sym.value)
}
continue
} else if sym.sectnum > 0 && uint(sym.sectnum) <= peobj.nsect {
sect = &peobj.sect[sym.sectnum-1]
if sect.sym == nil {
Diag("%s: %s sym == 0!", pn, s.Name)
}
} else {
Diag("%s: %s sectnum < 0!", pn, s.Name)
}
if sect == nil {
return
}
if s.Outer != nil {
if s.Attr.DuplicateOK() {
continue
}
Exitf("%s: duplicate symbol reference: %s in both %s and %s", pn, s.Name, s.Outer.Name, sect.sym.Name)
}
s.Sub = sect.sym.Sub
sect.sym.Sub = s
s.Type = sect.sym.Type | obj.SSUB
s.Value = int64(sym.value)
s.Size = 4
s.Outer = sect.sym
if sect.sym.Type == obj.STEXT {
if s.Attr.External() && !s.Attr.DuplicateOK() {
Diag("%s: duplicate definition of %s", pn, s.Name)
}
s.Attr |= AttrExternal
}
}
// Sort outer lists by address, adding to textp.
// This keeps textp in increasing address order.
for i := 0; uint(i) < peobj.nsect; i++ {
s = peobj.sect[i].sym
if s == nil {
continue
}
if s.Sub != nil {
s.Sub = listsort(s.Sub, valuecmp, listsubp)
}
if s.Type == obj.STEXT {
if s.Attr.OnList() {
log.Fatalf("symbol %s listed multiple times", s.Name)
}
s.Attr |= AttrOnList
Ctxt.Textp = append(Ctxt.Textp, s)
for s = s.Sub; s != nil; s = s.Sub {
if s.Attr.OnList() {
log.Fatalf("symbol %s listed multiple times", s.Name)
}
s.Attr |= AttrOnList
Ctxt.Textp = append(Ctxt.Textp, s)
}
}
}
return
bad:
Diag("%s: malformed pe file: %v", pn, err)
}
func ldmacho(f *bio.Reader, pkg string, length int64, pn string) {
var err error
var j int
var is64 bool
var secaddr uint64
var hdr [7 * 4]uint8
var cmdp []byte
var dat []byte
var ncmd uint32
var cmdsz uint32
var ty uint32
var sz uint32
var off uint32
var m *LdMachoObj
var e binary.ByteOrder
var sect *LdMachoSect
var rel *LdMachoRel
var rpi int
var s *LSym
var s1 *LSym
var outer *LSym
var c *LdMachoCmd
var symtab *LdMachoSymtab
var dsymtab *LdMachoDysymtab
var sym *LdMachoSym
var r []Reloc
var rp *Reloc
var name string
Ctxt.IncVersion()
base := f.Offset()
if _, err := io.ReadFull(f, hdr[:]); err != nil {
goto bad
}
if binary.BigEndian.Uint32(hdr[:])&^1 == 0xFEEDFACE {
e = binary.BigEndian
} else if binary.LittleEndian.Uint32(hdr[:])&^1 == 0xFEEDFACE {
e = binary.LittleEndian
} else {
err = fmt.Errorf("bad magic - not mach-o file")
goto bad
}
is64 = e.Uint32(hdr[:]) == 0xFEEDFACF
ncmd = e.Uint32(hdr[4*4:])
cmdsz = e.Uint32(hdr[5*4:])
if ncmd > 0x10000 || cmdsz >= 0x01000000 {
err = fmt.Errorf("implausible mach-o header ncmd=%d cmdsz=%d", ncmd, cmdsz)
goto bad
}
if is64 {
f.Seek(4, 1) // skip reserved word in header
}
m = new(LdMachoObj)
m.f = f
m.e = e
m.cputype = uint(e.Uint32(hdr[1*4:]))
m.subcputype = uint(e.Uint32(hdr[2*4:]))
m.filetype = e.Uint32(hdr[3*4:])
m.ncmd = uint(ncmd)
m.flags = e.Uint32(hdr[6*4:])
m.is64 = is64
m.base = base
m.length = length
m.name = pn
switch SysArch.Family {
default:
Diag("%s: mach-o %s unimplemented", pn, SysArch.Name)
return
case sys.AMD64:
if e != binary.LittleEndian || m.cputype != LdMachoCpuAmd64 {
Diag("%s: mach-o object but not amd64", pn)
return
}
case sys.I386:
if e != binary.LittleEndian || m.cputype != LdMachoCpu386 {
Diag("%s: mach-o object but not 386", pn)
return
}
}
m.cmd = make([]LdMachoCmd, ncmd)
off = uint32(len(hdr))
cmdp = make([]byte, cmdsz)
if _, err2 := io.ReadFull(f, cmdp); err2 != nil {
err = fmt.Errorf("reading cmds: %v", err)
goto bad
}
// read and parse load commands
c = nil
symtab = nil
dsymtab = nil
for i := 0; uint32(i) < ncmd; i++ {
ty = e.Uint32(cmdp)
sz = e.Uint32(cmdp[4:])
m.cmd[i].off = off
unpackcmd(cmdp, m, &m.cmd[i], uint(ty), uint(sz))
cmdp = cmdp[sz:]
off += sz
if ty == LdMachoCmdSymtab {
if symtab != nil {
err = fmt.Errorf("multiple symbol tables")
goto bad
}
symtab = &m.cmd[i].sym
macholoadsym(m, symtab)
}
if ty == LdMachoCmdDysymtab {
dsymtab = &m.cmd[i].dsym
macholoaddsym(m, dsymtab)
}
if (is64 && ty == LdMachoCmdSegment64) || (!is64 && ty == LdMachoCmdSegment) {
if c != nil {
err = fmt.Errorf("multiple load commands")
goto bad
}
c = &m.cmd[i]
}
}
// load text and data segments into memory.
// they are not as small as the load commands, but we'll need
// the memory anyway for the symbol images, so we might
// as well use one large chunk.
if c == nil {
err = fmt.Errorf("no load command")
goto bad
}
if symtab == nil {
// our work is done here - no symbols means nothing can refer to this file
return
}
if int64(c.seg.fileoff+c.seg.filesz) >= length {
err = fmt.Errorf("load segment out of range")
goto bad
}
dat = make([]byte, c.seg.filesz)
if f.Seek(m.base+int64(c.seg.fileoff), 0) < 0 {
err = fmt.Errorf("cannot load object data: %v", err)
goto bad
}
if _, err2 := io.ReadFull(f, dat); err2 != nil {
err = fmt.Errorf("cannot load object data: %v", err)
goto bad
}
for i := 0; uint32(i) < c.seg.nsect; i++ {
sect = &c.seg.sect[i]
if sect.segname != "__TEXT" && sect.segname != "__DATA" {
continue
}
if sect.name == "__eh_frame" {
continue
}
name = fmt.Sprintf("%s(%s/%s)", pkg, sect.segname, sect.name)
s = Linklookup(Ctxt, name, Ctxt.Version)
if s.Type != 0 {
err = fmt.Errorf("duplicate %s/%s", sect.segname, sect.name)
goto bad
}
if sect.flags&0xff == 1 { // S_ZEROFILL
s.P = make([]byte, sect.size)
} else {
s.P = dat[sect.addr-c.seg.vmaddr:][:sect.size]
}
s.Size = int64(len(s.P))
if sect.segname == "__TEXT" {
if sect.name == "__text" {
s.Type = obj.STEXT
} else {
s.Type = obj.SRODATA
}
} else {
if sect.name == "__bss" {
s.Type = obj.SNOPTRBSS
s.P = s.P[:0]
} else {
s.Type = obj.SNOPTRDATA
}
}
sect.sym = s
}
// enter sub-symbols into symbol table.
// have to guess sizes from next symbol.
for i := 0; uint32(i) < symtab.nsym; i++ {
sym = &symtab.sym[i]
if sym.type_&N_STAB != 0 {
continue
}
// TODO: check sym->type against outer->type.
name = sym.name
if name[0] == '_' && name[1] != '\x00' {
name = name[1:]
}
v := 0
if sym.type_&N_EXT == 0 {
v = Ctxt.Version
}
s = Linklookup(Ctxt, name, v)
if sym.type_&N_EXT == 0 {
s.Attr |= AttrDuplicateOK
}
sym.sym = s
if sym.sectnum == 0 { // undefined
continue
}
if uint32(sym.sectnum) > c.seg.nsect {
err = fmt.Errorf("reference to invalid section %d", sym.sectnum)
goto bad
}
sect = &c.seg.sect[sym.sectnum-1]
outer = sect.sym
if outer == nil {
err = fmt.Errorf("reference to invalid section %s/%s", sect.segname, sect.name)
continue
}
if s.Outer != nil {
if s.Attr.DuplicateOK() {
continue
}
Exitf("%s: duplicate symbol reference: %s in both %s and %s", pn, s.Name, s.Outer.Name, sect.sym.Name)
}
s.Type = outer.Type | obj.SSUB
s.Sub = outer.Sub
outer.Sub = s
s.Outer = outer
s.Value = int64(sym.value - sect.addr)
if !s.Attr.CgoExportDynamic() {
s.Dynimplib = "" // satisfy dynimport
}
if outer.Type == obj.STEXT {
if s.Attr.External() && !s.Attr.DuplicateOK() {
Diag("%s: duplicate definition of %s", pn, s.Name)
}
s.Attr |= AttrExternal
}
sym.sym = s
}
// Sort outer lists by address, adding to textp.
// This keeps textp in increasing address order.
for i := 0; uint32(i) < c.seg.nsect; i++ {
sect = &c.seg.sect[i]
s = sect.sym
if s == nil {
continue
}
if s.Sub != nil {
s.Sub = listsort(s.Sub, valuecmp, listsubp)
// assign sizes, now that we know symbols in sorted order.
for s1 = s.Sub; s1 != nil; s1 = s1.Sub {
if s1.Sub != nil {
s1.Size = s1.Sub.Value - s1.Value
} else {
s1.Size = s.Value + s.Size - s1.Value
}
}
}
if s.Type == obj.STEXT {
if s.Attr.OnList() {
log.Fatalf("symbol %s listed multiple times", s.Name)
}
s.Attr |= AttrOnList
Ctxt.Textp = append(Ctxt.Textp, s)
for s1 = s.Sub; s1 != nil; s1 = s1.Sub {
if s1.Attr.OnList() {
log.Fatalf("symbol %s listed multiple times", s1.Name)
}
s1.Attr |= AttrOnList
Ctxt.Textp = append(Ctxt.Textp, s1)
}
}
}
// load relocations
for i := 0; uint32(i) < c.seg.nsect; i++ {
sect = &c.seg.sect[i]
s = sect.sym
if s == nil {
continue
}
macholoadrel(m, sect)
if sect.rel == nil {
continue
}
r = make([]Reloc, sect.nreloc)
rpi = 0
Reloc:
for j = 0; uint32(j) < sect.nreloc; j++ {
rp = &r[rpi]
rel = §.rel[j]
if rel.scattered != 0 {
if SysArch.Family != sys.I386 {
// mach-o only uses scattered relocation on 32-bit platforms
Diag("unexpected scattered relocation")
continue
}
// on 386, rewrite scattered 4/1 relocation and some
// scattered 2/1 relocation into the pseudo-pc-relative
// reference that it is.
// assume that the second in the pair is in this section
// and use that as the pc-relative base.
if uint32(j+1) >= sect.nreloc {
err = fmt.Errorf("unsupported scattered relocation %d", int(rel.type_))
goto bad
}
if sect.rel[j+1].scattered == 0 || sect.rel[j+1].type_ != 1 || (rel.type_ != 4 && rel.type_ != 2) || uint64(sect.rel[j+1].value) < sect.addr || uint64(sect.rel[j+1].value) >= sect.addr+sect.size {
err = fmt.Errorf("unsupported scattered relocation %d/%d", int(rel.type_), int(sect.rel[j+1].type_))
goto bad
}
rp.Siz = rel.length
rp.Off = int32(rel.addr)
// NOTE(rsc): I haven't worked out why (really when)
// we should ignore the addend on a
// scattered relocation, but it seems that the
// common case is we ignore it.
// It's likely that this is not strictly correct
// and that the math should look something
// like the non-scattered case below.
rp.Add = 0
// want to make it pc-relative aka relative to rp->off+4
// but the scatter asks for relative to off = sect->rel[j+1].value - sect->addr.
// adjust rp->add accordingly.
rp.Type = obj.R_PCREL
rp.Add += int64(uint64(int64(rp.Off)+4) - (uint64(sect.rel[j+1].value) - sect.addr))
// now consider the desired symbol.
// find the section where it lives.
var ks *LdMachoSect
for k := 0; uint32(k) < c.seg.nsect; k++ {
ks = &c.seg.sect[k]
if ks.addr <= uint64(rel.value) && uint64(rel.value) < ks.addr+ks.size {
if ks.sym != nil {
rp.Sym = ks.sym
rp.Add += int64(uint64(rel.value) - ks.addr)
} else if ks.segname == "__IMPORT" && ks.name == "__pointers" {
// handle reference to __IMPORT/__pointers.
// how much worse can this get?
// why are we supporting 386 on the mac anyway?
rp.Type = 512 + MACHO_FAKE_GOTPCREL
// figure out which pointer this is a reference to.
k = int(uint64(ks.res1) + (uint64(rel.value)-ks.addr)/4)
// load indirect table for __pointers
// fetch symbol number
if dsymtab == nil || k < 0 || uint32(k) >= dsymtab.nindirectsyms || dsymtab.indir == nil {
err = fmt.Errorf("invalid scattered relocation: indirect symbol reference out of range")
goto bad
}
k = int(dsymtab.indir[k])
if k < 0 || uint32(k) >= symtab.nsym {
err = fmt.Errorf("invalid scattered relocation: symbol reference out of range")
goto bad
}
rp.Sym = symtab.sym[k].sym
} else {
err = fmt.Errorf("unsupported scattered relocation: reference to %s/%s", ks.segname, ks.name)
goto bad
}
rpi++
// skip #1 of 2 rel; continue skips #2 of 2.
j++
continue Reloc
}
}
err = fmt.Errorf("unsupported scattered relocation: invalid address %#x", rel.addr)
goto bad
}
rp.Siz = rel.length
rp.Type = 512 + (int32(rel.type_) << 1) + int32(rel.pcrel)
rp.Off = int32(rel.addr)
// Handle X86_64_RELOC_SIGNED referencing a section (rel->extrn == 0).
if SysArch.Family == sys.AMD64 && rel.extrn == 0 && rel.type_ == 1 {
// Calculate the addend as the offset into the section.
//
// The rip-relative offset stored in the object file is encoded
// as follows:
//
// movsd 0x00000360(%rip),%xmm0
//
// To get the absolute address of the value this rip-relative address is pointing
// to, we must add the address of the next instruction to it. This is done by
// taking the address of the relocation and adding 4 to it (since the rip-relative
// offset can at most be 32 bits long). To calculate the offset into the section the
// relocation is referencing, we subtract the vaddr of the start of the referenced
// section found in the original object file.
//
// [For future reference, see Darwin's /usr/include/mach-o/x86_64/reloc.h]
secaddr = c.seg.sect[rel.symnum-1].addr
rp.Add = int64(uint64(int64(int32(e.Uint32(s.P[rp.Off:])))+int64(rp.Off)+4) - secaddr)
} else {
rp.Add = int64(int32(e.Uint32(s.P[rp.Off:])))
}
// For i386 Mach-O PC-relative, the addend is written such that
// it *is* the PC being subtracted. Use that to make
// it match our version of PC-relative.
if rel.pcrel != 0 && SysArch.Family == sys.I386 {
rp.Add += int64(rp.Off) + int64(rp.Siz)
}
if rel.extrn == 0 {
if rel.symnum < 1 || rel.symnum > c.seg.nsect {
err = fmt.Errorf("invalid relocation: section reference out of range %d vs %d", rel.symnum, c.seg.nsect)
goto bad
}
rp.Sym = c.seg.sect[rel.symnum-1].sym
if rp.Sym == nil {
err = fmt.Errorf("invalid relocation: %s", c.seg.sect[rel.symnum-1].name)
goto bad
}
// References to symbols in other sections
// include that information in the addend.
// We only care about the delta from the
// section base.
if SysArch.Family == sys.I386 {
rp.Add -= int64(c.seg.sect[rel.symnum-1].addr)
}
} else {
if rel.symnum >= symtab.nsym {
err = fmt.Errorf("invalid relocation: symbol reference out of range")
goto bad
}
rp.Sym = symtab.sym[rel.symnum].sym
}
rpi++
}
sort.Sort(rbyoff(r[:rpi]))
s.R = r
s.R = s.R[:rpi]
}
return
bad:
Diag("%s: malformed mach-o file: %v", pn, err)
}
func ldelf(f *bio.Reader, pkg string, length int64, pn string) {
if Debug['v'] != 0 {
fmt.Fprintf(Bso, "%5.2f ldelf %s\n", obj.Cputime(), pn)
}
Ctxt.IncVersion()
base := f.Offset()
var add uint64
var e binary.ByteOrder
var elfobj *ElfObj
var err error
var flag int
var hdr *ElfHdrBytes
var hdrbuf [64]uint8
var info uint64
var is64 int
var j int
var n int
var name string
var p []byte
var r []Reloc
var rela int
var rp *Reloc
var rsect *ElfSect
var s *LSym
var sect *ElfSect
var sym ElfSym
var symbols []*LSym
if _, err := io.ReadFull(f, hdrbuf[:]); err != nil {
goto bad
}
hdr = new(ElfHdrBytes)
binary.Read(bytes.NewReader(hdrbuf[:]), binary.BigEndian, hdr) // only byte arrays; byte order doesn't matter
if string(hdr.Ident[:4]) != "\x7FELF" {
goto bad
}
switch hdr.Ident[5] {
case ElfDataLsb:
e = binary.LittleEndian
case ElfDataMsb:
e = binary.BigEndian
default:
goto bad
}
// read header
elfobj = new(ElfObj)
elfobj.e = e
elfobj.f = f
elfobj.base = base
elfobj.length = length
elfobj.name = pn
is64 = 0
if hdr.Ident[4] == ElfClass64 {
is64 = 1
hdr := new(ElfHdrBytes64)
binary.Read(bytes.NewReader(hdrbuf[:]), binary.BigEndian, hdr) // only byte arrays; byte order doesn't matter
elfobj.type_ = uint32(e.Uint16(hdr.Type[:]))
elfobj.machine = uint32(e.Uint16(hdr.Machine[:]))
elfobj.version = e.Uint32(hdr.Version[:])
elfobj.phoff = e.Uint64(hdr.Phoff[:])
elfobj.shoff = e.Uint64(hdr.Shoff[:])
elfobj.flags = e.Uint32(hdr.Flags[:])
elfobj.ehsize = uint32(e.Uint16(hdr.Ehsize[:]))
elfobj.phentsize = uint32(e.Uint16(hdr.Phentsize[:]))
elfobj.phnum = uint32(e.Uint16(hdr.Phnum[:]))
elfobj.shentsize = uint32(e.Uint16(hdr.Shentsize[:]))
elfobj.shnum = uint32(e.Uint16(hdr.Shnum[:]))
elfobj.shstrndx = uint32(e.Uint16(hdr.Shstrndx[:]))
} else {
elfobj.type_ = uint32(e.Uint16(hdr.Type[:]))
elfobj.machine = uint32(e.Uint16(hdr.Machine[:]))
elfobj.version = e.Uint32(hdr.Version[:])
elfobj.entry = uint64(e.Uint32(hdr.Entry[:]))
elfobj.phoff = uint64(e.Uint32(hdr.Phoff[:]))
elfobj.shoff = uint64(e.Uint32(hdr.Shoff[:]))
elfobj.flags = e.Uint32(hdr.Flags[:])
elfobj.ehsize = uint32(e.Uint16(hdr.Ehsize[:]))
elfobj.phentsize = uint32(e.Uint16(hdr.Phentsize[:]))
elfobj.phnum = uint32(e.Uint16(hdr.Phnum[:]))
elfobj.shentsize = uint32(e.Uint16(hdr.Shentsize[:]))
elfobj.shnum = uint32(e.Uint16(hdr.Shnum[:]))
elfobj.shstrndx = uint32(e.Uint16(hdr.Shstrndx[:]))
}
elfobj.is64 = is64
if uint32(hdr.Ident[6]) != elfobj.version {
goto bad
}
if e.Uint16(hdr.Type[:]) != ElfTypeRelocatable {
Diag("%s: elf but not elf relocatable object", pn)
return
}
switch SysArch.Family {
default:
Diag("%s: elf %s unimplemented", pn, SysArch.Name)
return
case sys.MIPS64:
if elfobj.machine != ElfMachMips || hdr.Ident[4] != ElfClass64 {
Diag("%s: elf object but not mips64", pn)
return
}
case sys.ARM:
if e != binary.LittleEndian || elfobj.machine != ElfMachArm || hdr.Ident[4] != ElfClass32 {
Diag("%s: elf object but not arm", pn)
return
}
case sys.AMD64:
if e != binary.LittleEndian || elfobj.machine != ElfMachAmd64 || hdr.Ident[4] != ElfClass64 {
Diag("%s: elf object but not amd64", pn)
return
}
case sys.ARM64:
if e != binary.LittleEndian || elfobj.machine != ElfMachArm64 || hdr.Ident[4] != ElfClass64 {
Diag("%s: elf object but not arm64", pn)
return
}
case sys.I386:
if e != binary.LittleEndian || elfobj.machine != ElfMach386 || hdr.Ident[4] != ElfClass32 {
Diag("%s: elf object but not 386", pn)
return
}
case sys.PPC64:
if elfobj.machine != ElfMachPower64 || hdr.Ident[4] != ElfClass64 {
Diag("%s: elf object but not ppc64", pn)
return
}
case sys.S390X:
if elfobj.machine != ElfMachS390 || hdr.Ident[4] != ElfClass64 {
Diag("%s: elf object but not s390x", pn)
return
}
}
// load section list into memory.
elfobj.sect = make([]ElfSect, elfobj.shnum)
elfobj.nsect = uint(elfobj.shnum)
for i := 0; uint(i) < elfobj.nsect; i++ {
if f.Seek(int64(uint64(base)+elfobj.shoff+uint64(int64(i)*int64(elfobj.shentsize))), 0) < 0 {
goto bad
}
sect = &elfobj.sect[i]
if is64 != 0 {
var b ElfSectBytes64
if err = binary.Read(f, e, &b); err != nil {
goto bad
}
sect.nameoff = e.Uint32(b.Name[:])
sect.type_ = e.Uint32(b.Type[:])
sect.flags = e.Uint64(b.Flags[:])
sect.addr = e.Uint64(b.Addr[:])
sect.off = e.Uint64(b.Off[:])
sect.size = e.Uint64(b.Size[:])
sect.link = e.Uint32(b.Link[:])
sect.info = e.Uint32(b.Info[:])
sect.align = e.Uint64(b.Align[:])
sect.entsize = e.Uint64(b.Entsize[:])
} else {
var b ElfSectBytes
if err = binary.Read(f, e, &b); err != nil {
goto bad
}
sect.nameoff = e.Uint32(b.Name[:])
sect.type_ = e.Uint32(b.Type[:])
sect.flags = uint64(e.Uint32(b.Flags[:]))
sect.addr = uint64(e.Uint32(b.Addr[:]))
sect.off = uint64(e.Uint32(b.Off[:]))
sect.size = uint64(e.Uint32(b.Size[:]))
sect.link = e.Uint32(b.Link[:])
sect.info = e.Uint32(b.Info[:])
sect.align = uint64(e.Uint32(b.Align[:]))
sect.entsize = uint64(e.Uint32(b.Entsize[:]))
}
}
// read section string table and translate names
if elfobj.shstrndx >= uint32(elfobj.nsect) {
err = fmt.Errorf("shstrndx out of range %d >= %d", elfobj.shstrndx, elfobj.nsect)
goto bad
}
sect = &elfobj.sect[elfobj.shstrndx]
if err = elfmap(elfobj, sect); err != nil {
goto bad
}
for i := 0; uint(i) < elfobj.nsect; i++ {
if elfobj.sect[i].nameoff != 0 {
elfobj.sect[i].name = cstring(sect.base[elfobj.sect[i].nameoff:])
}
}
// load string table for symbols into memory.
elfobj.symtab = section(elfobj, ".symtab")
if elfobj.symtab == nil {
// our work is done here - no symbols means nothing can refer to this file
return
}
if elfobj.symtab.link <= 0 || elfobj.symtab.link >= uint32(elfobj.nsect) {
Diag("%s: elf object has symbol table with invalid string table link", pn)
return
}
elfobj.symstr = &elfobj.sect[elfobj.symtab.link]
if is64 != 0 {
elfobj.nsymtab = int(elfobj.symtab.size / ELF64SYMSIZE)
} else {
elfobj.nsymtab = int(elfobj.symtab.size / ELF32SYMSIZE)
}
if err = elfmap(elfobj, elfobj.symtab); err != nil {
goto bad
}
if err = elfmap(elfobj, elfobj.symstr); err != nil {
goto bad
}
// load text and data segments into memory.
// they are not as small as the section lists, but we'll need
// the memory anyway for the symbol images, so we might
// as well use one large chunk.
// create symbols for elfmapped sections
for i := 0; uint(i) < elfobj.nsect; i++ {
sect = &elfobj.sect[i]
if sect.type_ == SHT_ARM_ATTRIBUTES && sect.name == ".ARM.attributes" {
if err = elfmap(elfobj, sect); err != nil {
goto bad
}
parseArmAttributes(e, sect.base[:sect.size])
}
if (sect.type_ != ElfSectProgbits && sect.type_ != ElfSectNobits) || sect.flags&ElfSectFlagAlloc == 0 {
continue
}
if sect.type_ != ElfSectNobits {
if err = elfmap(elfobj, sect); err != nil {
goto bad
}
}
name = fmt.Sprintf("%s(%s)", pkg, sect.name)
s = Linklookup(Ctxt, name, Ctxt.Version)
switch int(sect.flags) & (ElfSectFlagAlloc | ElfSectFlagWrite | ElfSectFlagExec) {
default:
err = fmt.Errorf("unexpected flags for ELF section %s", sect.name)
goto bad
case ElfSectFlagAlloc:
s.Type = obj.SRODATA
case ElfSectFlagAlloc + ElfSectFlagWrite:
if sect.type_ == ElfSectNobits {
s.Type = obj.SNOPTRBSS
} else {
s.Type = obj.SNOPTRDATA
}
case ElfSectFlagAlloc + ElfSectFlagExec:
s.Type = obj.STEXT
}
if sect.name == ".got" || sect.name == ".toc" {
s.Type = obj.SELFGOT
}
if sect.type_ == ElfSectProgbits {
s.P = sect.base
s.P = s.P[:sect.size]
}
s.Size = int64(sect.size)
s.Align = int32(sect.align)
sect.sym = s
}
// enter sub-symbols into symbol table.
// symbol 0 is the null symbol.
symbols = make([]*LSym, elfobj.nsymtab)
for i := 1; i < elfobj.nsymtab; i++ {
if err = readelfsym(elfobj, i, &sym, 1); err != nil {
goto bad
}
symbols[i] = sym.sym
if sym.type_ != ElfSymTypeFunc && sym.type_ != ElfSymTypeObject && sym.type_ != ElfSymTypeNone {
continue
}
if sym.shndx == ElfSymShnCommon {
s = sym.sym
if uint64(s.Size) < sym.size {
s.Size = int64(sym.size)
}
if s.Type == 0 || s.Type == obj.SXREF {
s.Type = obj.SNOPTRBSS
}
continue
}
if uint(sym.shndx) >= elfobj.nsect || sym.shndx == 0 {
continue
}
// even when we pass needSym == 1 to readelfsym, it might still return nil to skip some unwanted symbols
if sym.sym == nil {
continue
}
sect = &elfobj.sect[sym.shndx]
if sect.sym == nil {
if strings.HasPrefix(sym.name, ".Linfo_string") { // clang does this
continue
}
if sym.name == "" && sym.type_ == 0 && sect.name == ".debug_str" {
// This reportedly happens with clang 3.7 on ARM.
// See issue 13139.
continue
}
if strings.HasPrefix(sym.name, ".LASF") { // gcc on s390x does this
continue
}
Diag("%s: sym#%d: ignoring %s in section %d (type %d)", pn, i, sym.name, sym.shndx, sym.type_)
continue
}
s = sym.sym
if s.Outer != nil {
if s.Attr.DuplicateOK() {
continue
}
Exitf("%s: duplicate symbol reference: %s in both %s and %s", pn, s.Name, s.Outer.Name, sect.sym.Name)
}
s.Sub = sect.sym.Sub
sect.sym.Sub = s
s.Type = sect.sym.Type | s.Type&^obj.SMASK | obj.SSUB
if !s.Attr.CgoExportDynamic() {
s.Dynimplib = "" // satisfy dynimport
}
s.Value = int64(sym.value)
s.Size = int64(sym.size)
s.Outer = sect.sym
if sect.sym.Type == obj.STEXT {
if s.Attr.External() && !s.Attr.DuplicateOK() {
Diag("%s: duplicate definition of %s", pn, s.Name)
}
s.Attr |= AttrExternal
}
if elfobj.machine == ElfMachPower64 {
flag = int(sym.other) >> 5
if 2 <= flag && flag <= 6 {
s.Localentry = 1 << uint(flag-2)
} else if flag == 7 {
Diag("%s: invalid sym.other 0x%x for %s", pn, sym.other, s.Name)
}
}
}
// Sort outer lists by address, adding to textp.
// This keeps textp in increasing address order.
for i := 0; uint(i) < elfobj.nsect; i++ {
s = elfobj.sect[i].sym
if s == nil {
continue
}
if s.Sub != nil {
s.Sub = listsort(s.Sub, valuecmp, listsubp)
}
if s.Type == obj.STEXT {
if s.Attr.OnList() {
log.Fatalf("symbol %s listed multiple times", s.Name)
}
s.Attr |= AttrOnList
Ctxt.Textp = append(Ctxt.Textp, s)
for s = s.Sub; s != nil; s = s.Sub {
if s.Attr.OnList() {
log.Fatalf("symbol %s listed multiple times", s.Name)
}
s.Attr |= AttrOnList
Ctxt.Textp = append(Ctxt.Textp, s)
}
}
}
// load relocations
for i := 0; uint(i) < elfobj.nsect; i++ {
rsect = &elfobj.sect[i]
if rsect.type_ != ElfSectRela && rsect.type_ != ElfSectRel {
continue
}
if rsect.info >= uint32(elfobj.nsect) || elfobj.sect[rsect.info].base == nil {
continue
}
sect = &elfobj.sect[rsect.info]
if err = elfmap(elfobj, rsect); err != nil {
goto bad
}
rela = 0
if rsect.type_ == ElfSectRela {
rela = 1
}
n = int(rsect.size / uint64(4+4*is64) / uint64(2+rela))
r = make([]Reloc, n)
p = rsect.base
for j = 0; j < n; j++ {
add = 0
rp = &r[j]
if is64 != 0 {
// 64-bit rel/rela
rp.Off = int32(e.Uint64(p))
p = p[8:]
info = e.Uint64(p)
p = p[8:]
if rela != 0 {
add = e.Uint64(p)
p = p[8:]
}
} else {
// 32-bit rel/rela
rp.Off = int32(e.Uint32(p))
p = p[4:]
info = uint64(e.Uint32(p))
info = info>>8<<32 | info&0xff // convert to 64-bit info
p = p[4:]
if rela != 0 {
add = uint64(e.Uint32(p))
p = p[4:]
}
}
if info&0xffffffff == 0 { // skip R_*_NONE relocation
j--
n--
continue
}
if info>>32 == 0 { // absolute relocation, don't bother reading the null symbol
rp.Sym = nil
} else {
if err = readelfsym(elfobj, int(info>>32), &sym, 0); err != nil {
goto bad
}
sym.sym = symbols[info>>32]
if sym.sym == nil {
err = fmt.Errorf("%s#%d: reloc of invalid sym #%d %s shndx=%d type=%d", sect.sym.Name, j, int(info>>32), sym.name, sym.shndx, sym.type_)
goto bad
}
rp.Sym = sym.sym
}
rp.Type = 256 + int32(info)
rp.Siz = relSize(pn, uint32(info))
if rela != 0 {
rp.Add = int64(add)
} else {
// load addend from image
if rp.Siz == 4 {
rp.Add = int64(e.Uint32(sect.base[rp.Off:]))
} else if rp.Siz == 8 {
rp.Add = int64(e.Uint64(sect.base[rp.Off:]))
} else {
Diag("invalid rela size %d", rp.Siz)
}
}
if rp.Siz == 2 {
rp.Add = int64(int16(rp.Add))
}
if rp.Siz == 4 {
rp.Add = int64(int32(rp.Add))
}
}
//print("rel %s %d %d %s %#llx\n", sect->sym->name, rp->type, rp->siz, rp->sym->name, rp->add);
sort.Sort(rbyoff(r[:n]))
// just in case
s = sect.sym
s.R = r
s.R = s.R[:n]
}
return
bad:
Diag("%s: malformed elf file: %v", pn, err)
}