Adding upstream version 1.21.8.upstream/1.21.8

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 697 insertions, 0 deletions

diff --git a/src/internal/xcoff/file.go b/src/internal/xcoff/file.go
new file mode 100644
index 0000000..9135822
--- /dev/null
+++ b/src/internal/xcoff/file.go
@@ -0,0 +1,697 @@
+// Copyright 2018 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 xcoff implements access to XCOFF (Extended Common Object File Format) files.
+package xcoff
+
+import (
+	"debug/dwarf"
+	"encoding/binary"
+	"fmt"
+	"internal/saferio"
+	"io"
+	"os"
+	"strings"
+)
+
+// SectionHeader holds information about an XCOFF section header.
+type SectionHeader struct {
+	Name           string
+	VirtualAddress uint64
+	Size           uint64
+	Type           uint32
+	Relptr         uint64
+	Nreloc         uint32
+}
+
+type Section struct {
+	SectionHeader
+	Relocs []Reloc
+	io.ReaderAt
+	sr *io.SectionReader
+}
+
+// AuxiliaryCSect holds information about an XCOFF symbol in an AUX_CSECT entry.
+type AuxiliaryCSect struct {
+	Length              int64
+	StorageMappingClass int
+	SymbolType          int
+}
+
+// AuxiliaryFcn holds information about an XCOFF symbol in an AUX_FCN entry.
+type AuxiliaryFcn struct {
+	Size int64
+}
+
+type Symbol struct {
+	Name          string
+	Value         uint64
+	SectionNumber int
+	StorageClass  int
+	AuxFcn        AuxiliaryFcn
+	AuxCSect      AuxiliaryCSect
+}
+
+type Reloc struct {
+	VirtualAddress   uint64
+	Symbol           *Symbol
+	Signed           bool
+	InstructionFixed bool
+	Length           uint8
+	Type             uint8
+}
+
+// ImportedSymbol holds information about an imported XCOFF symbol.
+type ImportedSymbol struct {
+	Name    string
+	Library string
+}
+
+// FileHeader holds information about an XCOFF file header.
+type FileHeader struct {
+	TargetMachine uint16
+}
+
+// A File represents an open XCOFF file.
+type File struct {
+	FileHeader
+	Sections     []*Section
+	Symbols      []*Symbol
+	StringTable  []byte
+	LibraryPaths []string
+
+	closer io.Closer
+}
+
+// Open opens the named file using os.Open and prepares it for use as an XCOFF binary.
+func Open(name string) (*File, error) {
+	f, err := os.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	ff, err := NewFile(f)
+	if err != nil {
+		f.Close()
+		return nil, err
+	}
+	ff.closer = f
+	return ff, nil
+}
+
+// Close closes the File.
+// If the File was created using NewFile directly instead of Open,
+// Close has no effect.
+func (f *File) Close() error {
+	var err error
+	if f.closer != nil {
+		err = f.closer.Close()
+		f.closer = nil
+	}
+	return err
+}
+
+// Section returns the first section with the given name, or nil if no such
+// section exists.
+// Xcoff have section's name limited to 8 bytes. Some sections like .gosymtab
+// can be trunked but this method will still find them.
+func (f *File) Section(name string) *Section {
+	for _, s := range f.Sections {
+		if s.Name == name || (len(name) > 8 && s.Name == name[:8]) {
+			return s
+		}
+	}
+	return nil
+}
+
+// SectionByType returns the first section in f with the
+// given type, or nil if there is no such section.
+func (f *File) SectionByType(typ uint32) *Section {
+	for _, s := range f.Sections {
+		if s.Type == typ {
+			return s
+		}
+	}
+	return nil
+}
+
+// cstring converts ASCII byte sequence b to string.
+// It stops once it finds 0 or reaches end of b.
+func cstring(b []byte) string {
+	var i int
+	for i = 0; i < len(b) && b[i] != 0; i++ {
+	}
+	return string(b[:i])
+}
+
+// getString extracts a string from an XCOFF string table.
+func getString(st []byte, offset uint32) (string, bool) {
+	if offset < 4 || int(offset) >= len(st) {
+		return "", false
+	}
+	return cstring(st[offset:]), true
+}
+
+// NewFile creates a new File for accessing an XCOFF binary in an underlying reader.
+func NewFile(r io.ReaderAt) (*File, error) {
+	sr := io.NewSectionReader(r, 0, 1<<63-1)
+	// Read XCOFF target machine
+	var magic uint16
+	if err := binary.Read(sr, binary.BigEndian, &magic); err != nil {
+		return nil, err
+	}
+	if magic != U802TOCMAGIC && magic != U64_TOCMAGIC {
+		return nil, fmt.Errorf("unrecognised XCOFF magic: 0x%x", magic)
+	}
+
+	f := new(File)
+	f.TargetMachine = magic
+
+	// Read XCOFF file header
+	if _, err := sr.Seek(0, io.SeekStart); err != nil {
+		return nil, err
+	}
+	var nscns uint16
+	var symptr uint64
+	var nsyms uint32
+	var opthdr uint16
+	var hdrsz int
+	switch f.TargetMachine {
+	case U802TOCMAGIC:
+		fhdr := new(FileHeader32)
+		if err := binary.Read(sr, binary.BigEndian, fhdr); err != nil {
+			return nil, err
+		}
+		nscns = fhdr.Fnscns
+		symptr = uint64(fhdr.Fsymptr)
+		nsyms = fhdr.Fnsyms
+		opthdr = fhdr.Fopthdr
+		hdrsz = FILHSZ_32
+	case U64_TOCMAGIC:
+		fhdr := new(FileHeader64)
+		if err := binary.Read(sr, binary.BigEndian, fhdr); err != nil {
+			return nil, err
+		}
+		nscns = fhdr.Fnscns
+		symptr = fhdr.Fsymptr
+		nsyms = fhdr.Fnsyms
+		opthdr = fhdr.Fopthdr
+		hdrsz = FILHSZ_64
+	}
+
+	if symptr == 0 || nsyms <= 0 {
+		return nil, fmt.Errorf("no symbol table")
+	}
+
+	// Read string table (located right after symbol table).
+	offset := symptr + uint64(nsyms)*SYMESZ
+	if _, err := sr.Seek(int64(offset), io.SeekStart); err != nil {
+		return nil, err
+	}
+	// The first 4 bytes contain the length (in bytes).
+	var l uint32
+	if err := binary.Read(sr, binary.BigEndian, &l); err != nil {
+		return nil, err
+	}
+	if l > 4 {
+		st, err := saferio.ReadDataAt(sr, uint64(l), int64(offset))
+		if err != nil {
+			return nil, err
+		}
+		f.StringTable = st
+	}
+
+	// Read section headers
+	if _, err := sr.Seek(int64(hdrsz)+int64(opthdr), io.SeekStart); err != nil {
+		return nil, err
+	}
+	c := saferio.SliceCap((**Section)(nil), uint64(nscns))
+	if c < 0 {
+		return nil, fmt.Errorf("too many XCOFF sections (%d)", nscns)
+	}
+	f.Sections = make([]*Section, 0, c)
+	for i := 0; i < int(nscns); i++ {
+		var scnptr uint64
+		s := new(Section)
+		switch f.TargetMachine {
+		case U802TOCMAGIC:
+			shdr := new(SectionHeader32)
+			if err := binary.Read(sr, binary.BigEndian, shdr); err != nil {
+				return nil, err
+			}
+			s.Name = cstring(shdr.Sname[:])
+			s.VirtualAddress = uint64(shdr.Svaddr)
+			s.Size = uint64(shdr.Ssize)
+			scnptr = uint64(shdr.Sscnptr)
+			s.Type = shdr.Sflags
+			s.Relptr = uint64(shdr.Srelptr)
+			s.Nreloc = uint32(shdr.Snreloc)
+		case U64_TOCMAGIC:
+			shdr := new(SectionHeader64)
+			if err := binary.Read(sr, binary.BigEndian, shdr); err != nil {
+				return nil, err
+			}
+			s.Name = cstring(shdr.Sname[:])
+			s.VirtualAddress = shdr.Svaddr
+			s.Size = shdr.Ssize
+			scnptr = shdr.Sscnptr
+			s.Type = shdr.Sflags
+			s.Relptr = shdr.Srelptr
+			s.Nreloc = shdr.Snreloc
+		}
+		r2 := r
+		if scnptr == 0 { // .bss must have all 0s
+			r2 = zeroReaderAt{}
+		}
+		s.sr = io.NewSectionReader(r2, int64(scnptr), int64(s.Size))
+		s.ReaderAt = s.sr
+		f.Sections = append(f.Sections, s)
+	}
+
+	// Symbol map needed by relocation
+	var idxToSym = make(map[int]*Symbol)
+
+	// Read symbol table
+	if _, err := sr.Seek(int64(symptr), io.SeekStart); err != nil {
+		return nil, err
+	}
+	f.Symbols = make([]*Symbol, 0)
+	for i := 0; i < int(nsyms); i++ {
+		var numaux int
+		var ok, needAuxFcn bool
+		sym := new(Symbol)
+		switch f.TargetMachine {
+		case U802TOCMAGIC:
+			se := new(SymEnt32)
+			if err := binary.Read(sr, binary.BigEndian, se); err != nil {
+				return nil, err
+			}
+			numaux = int(se.Nnumaux)
+			sym.SectionNumber = int(se.Nscnum)
+			sym.StorageClass = int(se.Nsclass)
+			sym.Value = uint64(se.Nvalue)
+			needAuxFcn = se.Ntype&SYM_TYPE_FUNC != 0 && numaux > 1
+			zeroes := binary.BigEndian.Uint32(se.Nname[:4])
+			if zeroes != 0 {
+				sym.Name = cstring(se.Nname[:])
+			} else {
+				offset := binary.BigEndian.Uint32(se.Nname[4:])
+				sym.Name, ok = getString(f.StringTable, offset)
+				if !ok {
+					goto skip
+				}
+			}
+		case U64_TOCMAGIC:
+			se := new(SymEnt64)
+			if err := binary.Read(sr, binary.BigEndian, se); err != nil {
+				return nil, err
+			}
+			numaux = int(se.Nnumaux)
+			sym.SectionNumber = int(se.Nscnum)
+			sym.StorageClass = int(se.Nsclass)
+			sym.Value = se.Nvalue
+			needAuxFcn = se.Ntype&SYM_TYPE_FUNC != 0 && numaux > 1
+			sym.Name, ok = getString(f.StringTable, se.Noffset)
+			if !ok {
+				goto skip
+			}
+		}
+		if sym.StorageClass != C_EXT && sym.StorageClass != C_WEAKEXT && sym.StorageClass != C_HIDEXT {
+			goto skip
+		}
+		// Must have at least one csect auxiliary entry.
+		if numaux < 1 || i+numaux >= int(nsyms) {
+			goto skip
+		}
+
+		if sym.SectionNumber > int(nscns) {
+			goto skip
+		}
+		if sym.SectionNumber == 0 {
+			sym.Value = 0
+		} else {
+			sym.Value -= f.Sections[sym.SectionNumber-1].VirtualAddress
+		}
+
+		idxToSym[i] = sym
+
+		// If this symbol is a function, it must retrieve its size from
+		// its AUX_FCN entry.
+		// It can happen that a function symbol doesn't have any AUX_FCN.
+		// In this case, needAuxFcn is false and their size will be set to 0.
+		if needAuxFcn {
+			switch f.TargetMachine {
+			case U802TOCMAGIC:
+				aux := new(AuxFcn32)
+				if err := binary.Read(sr, binary.BigEndian, aux); err != nil {
+					return nil, err
+				}
+				sym.AuxFcn.Size = int64(aux.Xfsize)
+			case U64_TOCMAGIC:
+				aux := new(AuxFcn64)
+				if err := binary.Read(sr, binary.BigEndian, aux); err != nil {
+					return nil, err
+				}
+				sym.AuxFcn.Size = int64(aux.Xfsize)
+			}
+		}
+
+		// Read csect auxiliary entry (by convention, it is the last).
+		if !needAuxFcn {
+			if _, err := sr.Seek(int64(numaux-1)*SYMESZ, io.SeekCurrent); err != nil {
+				return nil, err
+			}
+		}
+		i += numaux
+		numaux = 0
+		switch f.TargetMachine {
+		case U802TOCMAGIC:
+			aux := new(AuxCSect32)
+			if err := binary.Read(sr, binary.BigEndian, aux); err != nil {
+				return nil, err
+			}
+			sym.AuxCSect.SymbolType = int(aux.Xsmtyp & 0x7)
+			sym.AuxCSect.StorageMappingClass = int(aux.Xsmclas)
+			sym.AuxCSect.Length = int64(aux.Xscnlen)
+		case U64_TOCMAGIC:
+			aux := new(AuxCSect64)
+			if err := binary.Read(sr, binary.BigEndian, aux); err != nil {
+				return nil, err
+			}
+			sym.AuxCSect.SymbolType = int(aux.Xsmtyp & 0x7)
+			sym.AuxCSect.StorageMappingClass = int(aux.Xsmclas)
+			sym.AuxCSect.Length = int64(aux.Xscnlenhi)<<32 | int64(aux.Xscnlenlo)
+		}
+		f.Symbols = append(f.Symbols, sym)
+	skip:
+		i += numaux // Skip auxiliary entries
+		if _, err := sr.Seek(int64(numaux)*SYMESZ, io.SeekCurrent); err != nil {
+			return nil, err
+		}
+	}
+
+	// Read relocations
+	// Only for .data or .text section
+	for sectNum, sect := range f.Sections {
+		if sect.Type != STYP_TEXT && sect.Type != STYP_DATA {
+			continue
+		}
+		if sect.Relptr == 0 {
+			continue
+		}
+		c := saferio.SliceCap((*Reloc)(nil), uint64(sect.Nreloc))
+		if c < 0 {
+			return nil, fmt.Errorf("too many relocs (%d) for section %d", sect.Nreloc, sectNum)
+		}
+		sect.Relocs = make([]Reloc, 0, c)
+		if _, err := sr.Seek(int64(sect.Relptr), io.SeekStart); err != nil {
+			return nil, err
+		}
+		for i := uint32(0); i < sect.Nreloc; i++ {
+			var reloc Reloc
+			switch f.TargetMachine {
+			case U802TOCMAGIC:
+				rel := new(Reloc32)
+				if err := binary.Read(sr, binary.BigEndian, rel); err != nil {
+					return nil, err
+				}
+				reloc.VirtualAddress = uint64(rel.Rvaddr)
+				reloc.Symbol = idxToSym[int(rel.Rsymndx)]
+				reloc.Type = rel.Rtype
+				reloc.Length = rel.Rsize&0x3F + 1
+
+				if rel.Rsize&0x80 != 0 {
+					reloc.Signed = true
+				}
+				if rel.Rsize&0x40 != 0 {
+					reloc.InstructionFixed = true
+				}
+
+			case U64_TOCMAGIC:
+				rel := new(Reloc64)
+				if err := binary.Read(sr, binary.BigEndian, rel); err != nil {
+					return nil, err
+				}
+				reloc.VirtualAddress = rel.Rvaddr
+				reloc.Symbol = idxToSym[int(rel.Rsymndx)]
+				reloc.Type = rel.Rtype
+				reloc.Length = rel.Rsize&0x3F + 1
+				if rel.Rsize&0x80 != 0 {
+					reloc.Signed = true
+				}
+				if rel.Rsize&0x40 != 0 {
+					reloc.InstructionFixed = true
+				}
+			}
+
+			sect.Relocs = append(sect.Relocs, reloc)
+		}
+	}
+
+	return f, nil
+}
+
+// zeroReaderAt is ReaderAt that reads 0s.
+type zeroReaderAt struct{}
+
+// ReadAt writes len(p) 0s into p.
+func (w zeroReaderAt) ReadAt(p []byte, off int64) (n int, err error) {
+	for i := range p {
+		p[i] = 0
+	}
+	return len(p), nil
+}
+
+// Data reads and returns the contents of the XCOFF section s.
+func (s *Section) Data() ([]byte, error) {
+	dat := make([]byte, s.sr.Size())
+	n, err := s.sr.ReadAt(dat, 0)
+	if n == len(dat) {
+		err = nil
+	}
+	return dat[:n], err
+}
+
+// CSect reads and returns the contents of a csect.
+func (f *File) CSect(name string) []byte {
+	for _, sym := range f.Symbols {
+		if sym.Name == name && sym.AuxCSect.SymbolType == XTY_SD {
+			if i := sym.SectionNumber - 1; 0 <= i && i < len(f.Sections) {
+				s := f.Sections[i]
+				if sym.Value+uint64(sym.AuxCSect.Length) <= s.Size {
+					dat := make([]byte, sym.AuxCSect.Length)
+					_, err := s.sr.ReadAt(dat, int64(sym.Value))
+					if err != nil {
+						return nil
+					}
+					return dat
+				}
+			}
+			break
+		}
+	}
+	return nil
+}
+
+func (f *File) DWARF() (*dwarf.Data, error) {
+	// There are many other DWARF sections, but these
+	// are the ones the debug/dwarf package uses.
+	// Don't bother loading others.
+	var subtypes = [...]uint32{SSUBTYP_DWABREV, SSUBTYP_DWINFO, SSUBTYP_DWLINE, SSUBTYP_DWRNGES, SSUBTYP_DWSTR}
+	var dat [len(subtypes)][]byte
+	for i, subtype := range subtypes {
+		s := f.SectionByType(STYP_DWARF | subtype)
+		if s != nil {
+			b, err := s.Data()
+			if err != nil && uint64(len(b)) < s.Size {
+				return nil, err
+			}
+			dat[i] = b
+		}
+	}
+
+	abbrev, info, line, ranges, str := dat[0], dat[1], dat[2], dat[3], dat[4]
+	return dwarf.New(abbrev, nil, nil, info, line, nil, ranges, str)
+}
+
+// readImportID returns the import file IDs stored inside the .loader section.
+// Library name pattern is either path/base/member or base/member
+func (f *File) readImportIDs(s *Section) ([]string, error) {
+	// Read loader header
+	if _, err := s.sr.Seek(0, io.SeekStart); err != nil {
+		return nil, err
+	}
+	var istlen uint32
+	var nimpid uint32
+	var impoff uint64
+	switch f.TargetMachine {
+	case U802TOCMAGIC:
+		lhdr := new(LoaderHeader32)
+		if err := binary.Read(s.sr, binary.BigEndian, lhdr); err != nil {
+			return nil, err
+		}
+		istlen = lhdr.Listlen
+		nimpid = lhdr.Lnimpid
+		impoff = uint64(lhdr.Limpoff)
+	case U64_TOCMAGIC:
+		lhdr := new(LoaderHeader64)
+		if err := binary.Read(s.sr, binary.BigEndian, lhdr); err != nil {
+			return nil, err
+		}
+		istlen = lhdr.Listlen
+		nimpid = lhdr.Lnimpid
+		impoff = lhdr.Limpoff
+	}
+
+	// Read loader import file ID table
+	if _, err := s.sr.Seek(int64(impoff), io.SeekStart); err != nil {
+		return nil, err
+	}
+	table := make([]byte, istlen)
+	if _, err := io.ReadFull(s.sr, table); err != nil {
+		return nil, err
+	}
+
+	offset := 0
+	// First import file ID is the default LIBPATH value
+	libpath := cstring(table[offset:])
+	f.LibraryPaths = strings.Split(libpath, ":")
+	offset += len(libpath) + 3 // 3 null bytes
+	all := make([]string, 0)
+	for i := 1; i < int(nimpid); i++ {
+		impidpath := cstring(table[offset:])
+		offset += len(impidpath) + 1
+		impidbase := cstring(table[offset:])
+		offset += len(impidbase) + 1
+		impidmem := cstring(table[offset:])
+		offset += len(impidmem) + 1
+		var path string
+		if len(impidpath) > 0 {
+			path = impidpath + "/" + impidbase + "/" + impidmem
+		} else {
+			path = impidbase + "/" + impidmem
+		}
+		all = append(all, path)
+	}
+
+	return all, nil
+}
+
+// ImportedSymbols returns the names of all symbols
+// referred to by the binary f that are expected to be
+// satisfied by other libraries at dynamic load time.
+// It does not return weak symbols.
+func (f *File) ImportedSymbols() ([]ImportedSymbol, error) {
+	s := f.SectionByType(STYP_LOADER)
+	if s == nil {
+		return nil, nil
+	}
+	// Read loader header
+	if _, err := s.sr.Seek(0, io.SeekStart); err != nil {
+		return nil, err
+	}
+	var stlen uint32
+	var stoff uint64
+	var nsyms uint32
+	var symoff uint64
+	switch f.TargetMachine {
+	case U802TOCMAGIC:
+		lhdr := new(LoaderHeader32)
+		if err := binary.Read(s.sr, binary.BigEndian, lhdr); err != nil {
+			return nil, err
+		}
+		stlen = lhdr.Lstlen
+		stoff = uint64(lhdr.Lstoff)
+		nsyms = lhdr.Lnsyms
+		symoff = LDHDRSZ_32
+	case U64_TOCMAGIC:
+		lhdr := new(LoaderHeader64)
+		if err := binary.Read(s.sr, binary.BigEndian, lhdr); err != nil {
+			return nil, err
+		}
+		stlen = lhdr.Lstlen
+		stoff = lhdr.Lstoff
+		nsyms = lhdr.Lnsyms
+		symoff = lhdr.Lsymoff
+	}
+
+	// Read loader section string table
+	if _, err := s.sr.Seek(int64(stoff), io.SeekStart); err != nil {
+		return nil, err
+	}
+	st := make([]byte, stlen)
+	if _, err := io.ReadFull(s.sr, st); err != nil {
+		return nil, err
+	}
+
+	// Read imported libraries
+	libs, err := f.readImportIDs(s)
+	if err != nil {
+		return nil, err
+	}
+
+	// Read loader symbol table
+	if _, err := s.sr.Seek(int64(symoff), io.SeekStart); err != nil {
+		return nil, err
+	}
+	all := make([]ImportedSymbol, 0)
+	for i := 0; i < int(nsyms); i++ {
+		var name string
+		var ifile uint32
+		var ok bool
+		switch f.TargetMachine {
+		case U802TOCMAGIC:
+			ldsym := new(LoaderSymbol32)
+			if err := binary.Read(s.sr, binary.BigEndian, ldsym); err != nil {
+				return nil, err
+			}
+			if ldsym.Lsmtype&0x40 == 0 {
+				continue // Imported symbols only
+			}
+			zeroes := binary.BigEndian.Uint32(ldsym.Lname[:4])
+			if zeroes != 0 {
+				name = cstring(ldsym.Lname[:])
+			} else {
+				offset := binary.BigEndian.Uint32(ldsym.Lname[4:])
+				name, ok = getString(st, offset)
+				if !ok {
+					continue
+				}
+			}
+			ifile = ldsym.Lifile
+		case U64_TOCMAGIC:
+			ldsym := new(LoaderSymbol64)
+			if err := binary.Read(s.sr, binary.BigEndian, ldsym); err != nil {
+				return nil, err
+			}
+			if ldsym.Lsmtype&0x40 == 0 {
+				continue // Imported symbols only
+			}
+			name, ok = getString(st, ldsym.Loffset)
+			if !ok {
+				continue
+			}
+			ifile = ldsym.Lifile
+		}
+		var sym ImportedSymbol
+		sym.Name = name
+		if ifile >= 1 && int(ifile) <= len(libs) {
+			sym.Library = libs[ifile-1]
+		}
+		all = append(all, sym)
+	}
+
+	return all, nil
+}
+
+// ImportedLibraries returns the names of all libraries
+// referred to by the binary f that are expected to be
+// linked with the binary at dynamic link time.
+func (f *File) ImportedLibraries() ([]string, error) {
+	s := f.SectionByType(STYP_LOADER)
+	if s == nil {
+		return nil, nil
+	}
+	all, err := f.readImportIDs(s)
+	return all, err
+}