// SeekToType moves the reader to the type specified by the entry,
// optionally resolving typedefs and pointer types. If the reader is set
// to a struct type the NextMemberVariable call can be used to walk all member data.
func (reader *Reader) SeekToType(entry *dwarf.Entry, resolveTypedefs bool, resolvePointerTypes bool) (*dwarf.Entry, error) {
offset, ok := entry.Val(dwarf.AttrType).(dwarf.Offset)
if !ok {
return nil, fmt.Errorf("entry does not have a type attribute")
}
// Seek to the first type offset
reader.Seek(offset)
// Walk the types to the base
for typeEntry, err := reader.Next(); typeEntry != nil; typeEntry, err = reader.Next() {
if err != nil {
return nil, err
}
if typeEntry.Tag == dwarf.TagTypedef && !resolveTypedefs {
return typeEntry, nil
}
if typeEntry.Tag == dwarf.TagPointerType && !resolvePointerTypes {
return typeEntry, nil
}
offset, ok = typeEntry.Val(dwarf.AttrType).(dwarf.Offset)
if !ok {
return typeEntry, nil
}
reader.Seek(offset)
}
return nil, fmt.Errorf("no type entry found")
}
func (d *DWARFHelper) toContentMethod(e *dwarf.Entry) (m content.Method, err error) {
if v, ok := e.Val(dwarf.AttrName).(string); ok {
m.Name.Relative = v
}
if v, ok := e.Val(dwarf.AttrType).(dwarf.Offset); ok {
if t, err := d.GetType(v); err != nil {
return m, err
} else {
m.Returns = append(m.Returns, content.Variable{Type: t})
}
} else {
m.Returns = append(m.Returns, content.Variable{Type: content.Type{Name: content.FullyQualifiedName{Relative: "void"}}})
}
m.Flags = d.Flags(e)
if !e.Children {
return
}
r := d.df.Reader()
r.Seek(e.Offset)
for {
e, err := r.Next()
if err != nil {
return m, err
} else if e == nil || e.Tag == 0 {
break
}
if e.Tag != dwarf.TagFormalParameter {
continue
}
var p content.Variable
if v, ok := e.Val(dwarf.AttrType).(dwarf.Offset); ok {
if t, err := d.GetType(v); err != nil {
return m, err
} else {
p.Type = t
}
}
if v, ok := e.Val(dwarf.AttrName).(string); ok {
p.Name.Relative = v
}
if v, ok := e.Val(dwarf.AttrArtificial).(bool); ok && v {
if p.Type.Flags&content.FLAG_TYPE_MASK != content.FLAG_TYPE_POINTER {
m.Parameters = append(m.Parameters, p)
continue
}
// C++ "this" pointer
t := p.Type.Specialization[0]
if t.Flags&content.FLAG_CONST != 0 {
m.Flags |= content.FLAG_CONST
}
//m.Name.Absolute = t.Name.Relative + "::" + m.Name.Relative
} else {
m.Parameters = append(m.Parameters, p)
}
}
return
}
//============================================================================
// processCompileUnit : Process a compile unit.
//----------------------------------------------------------------------------
func processCompileUnit(theReader *dwarf.Reader, depth int, theEntry *dwarf.Entry) {
// Process the entry
gCurrentFile = theEntry.Val(dwarf.AttrName).(string)
if theEntry.Children {
processChildren(theReader, depth+1, false)
}
gCurrentFile = ""
}
func (d *DWARFHelper) Flags(e *dwarf.Entry) (ret content.Flags) {
if v, ok := e.Val(dwarf.AttrAccessibility).(int64); ok {
switch v {
case 1:
ret |= content.FLAG_ACC_PUBLIC
case 2:
ret |= content.FLAG_ACC_PROTECTED
case 3:
ret |= content.FLAG_ACC_PRIVATE
}
}
return
}
//============================================================================
// processSubprogram : Process a subprogram.
//----------------------------------------------------------------------------
func processSubprogram(theReader *dwarf.Reader, depth int, theEntry *dwarf.Entry) {
var lowAddr uint64
var highAddr uint64
// Get the state we need
lowVal := theEntry.Val(dwarf.AttrLowpc)
highVal := theEntry.Val(dwarf.AttrHighpc)
if lowVal != nil && highVal != nil {
lowAddr = lowVal.(uint64)
highAddr = highVal.(uint64)
}
// Check for a match
if gTargetAddress >= lowAddr && gTargetAddress < highAddr {
name := theEntry.Val(dwarf.AttrName)
line := theEntry.Val(dwarf.AttrDeclLine)
fmt.Printf("%v (%v:%v)\n", name, path.Base(gCurrentFile), line)
}
// Process the entry
if theEntry.Children {
processChildren(theReader, depth+1, false)
}
}
func (d *DWARFHelper) toContentField(e *dwarf.Entry) (content.Field, error) {
var f content.Field
if v, ok := e.Val(dwarf.AttrName).(string); ok {
f.Name.Relative = v
}
if v, ok := e.Val(dwarf.AttrType).(dwarf.Offset); ok {
if t, err := d.GetType(v); err != nil {
return f, err
} else {
f.Type = t
}
}
f.Flags = d.Flags(e)
return f, nil
}
// dwarfSourceLineEntry tries to get file/line information from a
// DWARF compilation unit. Returns nil if it doesn't find anything.
func (f *file) dwarfSourceLineEntry(r *dwarf.Reader, entry *dwarf.Entry, addr uint64) []plugin.Frame {
lines, err := f.dwarf.LineReader(entry)
if err != nil {
return nil
}
var lentry dwarf.LineEntry
if err := lines.SeekPC(addr, &lentry); err != nil {
return nil
}
// Try to find the function name.
name := ""
FindName:
for entry, err := r.Next(); entry != nil && err == nil; entry, err = r.Next() {
if entry.Tag == dwarf.TagSubprogram {
ranges, err := f.dwarf.Ranges(entry)
if err != nil {
return nil
}
for _, pcs := range ranges {
if pcs[0] <= addr && addr < pcs[1] {
var ok bool
// TODO: AT_linkage_name, AT_MIPS_linkage_name.
name, ok = entry.Val(dwarf.AttrName).(string)
if ok {
break FindName
}
}
}
}
}
// TODO: Report inlined functions.
frames := []plugin.Frame{
{
Func: name,
File: lentry.File.Name,
Line: lentry.Line,
},
}
return frames
}
func (reader *Reader) InstructionsForEntry(entry *dwarf.Entry) ([]byte, error) {
if entry.Tag == dwarf.TagMember {
instructions, ok := entry.Val(dwarf.AttrDataMemberLoc).([]byte)
if !ok {
return nil, fmt.Errorf("member data has no data member location attribute")
}
// clone slice to prevent stomping on the dwarf data
return append([]byte{}, instructions...), nil
}
// non-member
instructions, ok := entry.Val(dwarf.AttrLocation).([]byte)
if !ok {
return nil, fmt.Errorf("entry has no location attribute")
}
// clone slice to prevent stomping on the dwarf data
return append([]byte{}, instructions...), nil
}
// Extracts the name, type, and value of a variable from a dwarf entry
func (thread *Thread) extractVariableFromEntry(entry *dwarf.Entry) (*Variable, error) {
if entry == nil {
return nil, fmt.Errorf("invalid entry")
}
if entry.Tag != dwarf.TagFormalParameter && entry.Tag != dwarf.TagVariable {
return nil, fmt.Errorf("invalid entry tag, only supports FormalParameter and Variable, got %s", entry.Tag.String())
}
n, ok := entry.Val(dwarf.AttrName).(string)
if !ok {
return nil, fmt.Errorf("type assertion failed")
}
offset, ok := entry.Val(dwarf.AttrType).(dwarf.Offset)
if !ok {
return nil, fmt.Errorf("type assertion failed")
}
data := thread.dbp.dwarf
t, err := data.Type(offset)
if err != nil {
return nil, err
}
instructions, ok := entry.Val(dwarf.AttrLocation).([]byte)
if !ok {
return nil, fmt.Errorf("type assertion failed")
}
val, err := thread.extractValue(instructions, 0, t, true)
if err != nil {
return nil, err
}
return &Variable{Name: n, Type: t.String(), Value: val}, nil
}
// Extracts the name and type of a variable from a dwarf entry
// then executes the instructions given in the DW_AT_location attribute to grab the variable's address
func (scope *EvalScope) extractVarInfoFromEntry(entry *dwarf.Entry, rdr *reader.Reader) (*Variable, error) {
if entry == nil {
return nil, fmt.Errorf("invalid entry")
}
if entry.Tag != dwarf.TagFormalParameter && entry.Tag != dwarf.TagVariable {
return nil, fmt.Errorf("invalid entry tag, only supports FormalParameter and Variable, got %s", entry.Tag.String())
}
n, ok := entry.Val(dwarf.AttrName).(string)
if !ok {
return nil, fmt.Errorf("type assertion failed")
}
offset, ok := entry.Val(dwarf.AttrType).(dwarf.Offset)
if !ok {
return nil, fmt.Errorf("type assertion failed")
}
t, err := scope.Type(offset)
if err != nil {
return nil, err
}
instructions, ok := entry.Val(dwarf.AttrLocation).([]byte)
if !ok {
return nil, fmt.Errorf("type assertion failed")
}
addr, err := op.ExecuteStackProgram(scope.CFA, instructions)
if err != nil {
return nil, err
}
return scope.newVariable(n, uintptr(addr), t), nil
}
func (thread *Thread) evaluateStructMember(parentEntry *dwarf.Entry, rdr *reader.Reader, memberName string) (*Variable, error) {
parentAddr, err := thread.extractVariableDataAddress(parentEntry, rdr)
if err != nil {
return nil, err
}
// Get parent variable name
parentName, ok := parentEntry.Val(dwarf.AttrName).(string)
if !ok {
return nil, fmt.Errorf("unable to retrive variable name")
}
// Seek reader to the type information so members can be iterated
_, err = rdr.SeekToType(parentEntry, true, true)
if err != nil {
return nil, err
}
// Iterate to find member by name
for memberEntry, err := rdr.NextMemberVariable(); memberEntry != nil; memberEntry, err = rdr.NextMemberVariable() {
if err != nil {
return nil, err
}
name, ok := memberEntry.Val(dwarf.AttrName).(string)
if !ok {
continue
}
if name == memberName {
// Nil ptr, wait until here to throw a nil pointer error to prioritize no such member error
if parentAddr == 0 {
return nil, fmt.Errorf("%s is nil", parentName)
}
memberInstr, err := rdr.InstructionsForEntry(memberEntry)
if err != nil {
return nil, err
}
offset, ok := memberEntry.Val(dwarf.AttrType).(dwarf.Offset)
if !ok {
return nil, fmt.Errorf("type assertion failed")
}
data := thread.dbp.dwarf
t, err := data.Type(offset)
if err != nil {
return nil, err
}
baseAddr := make([]byte, 8)
binary.LittleEndian.PutUint64(baseAddr, uint64(parentAddr))
parentInstructions := append([]byte{op.DW_OP_addr}, baseAddr...)
val, err := thread.extractValue(append(parentInstructions, memberInstr...), 0, t, true)
if err != nil {
return nil, err
}
return &Variable{Name: strings.Join([]string{parentName, memberName}, "."), Type: t.String(), Value: val}, nil
}
}
return nil, fmt.Errorf("%s has no member %s", parentName, memberName)
}