feat: support resolve symbols in mini debug info(".gnu_debugdata")

ebpf/go.mod

@@ -19,6 +19,7 @@ require (
 	github.com/prometheus/prometheus v0.51.2
 	github.com/samber/lo v1.38.1
 	github.com/stretchr/testify v1.9.0
+	github.com/ulikunitz/xz v0.5.12
 	golang.org/x/sys v0.25.0
 )
 

ebpf/go.sum

@@ -72,6 +72,8 @@ github.com/samber/lo v1.38.1 h1:j2XEAqXKb09Am4ebOg31SpvzUTTs6EN3VfgeLUhPdXM=
 github.com/samber/lo v1.38.1/go.mod h1:+m/ZKRl6ClXCE2Lgf3MsQlWfh4bn1bz6CXEOxnEXnEA=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/ulikunitz/xz v0.5.12 h1:37Nm15o69RwBkXM0J6A5OlE67RZTfzUxTj8fB3dfcsc=
+github.com/ulikunitz/xz v0.5.12/go.mod h1:nbz6k7qbPmH4IRqmfOplQw/tblSgqTqBwxkY0oWt/14=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
 go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 golang.org/x/exp v0.0.0-20240119083558-1b970713d09a h1:Q8/wZp0KX97QFTc2ywcOE0YRjZPVIx+MXInMzdvQqcA=

ebpf/symtab/elf.go

@@ -176,9 +176,30 @@ func (et *ElfTable) createSymbolTable(me *elf2.MMapedElfFile) (SymbolNameResolve
 		symbolOptions.FilterFrom = goTable.Index.Entry.Get(0)
 		symbolOptions.FilterTo = goTable.Index.End
 	}
-	symTable, symErr := me.NewSymbolTable(&symbolOptions)
+	origSymTable, origErr := me.NewSymbolTable(&symbolOptions)
+
+	var symTable elf2.SymbolTableInterface
+	var symErr error
+	if origErr == nil && origSymTable.HasSection(elf.SHT_SYMTAB) {
+		symTable = origSymTable
+		symErr = nil
+	} else {
+		miniSymTable, miniErr := me.NewMiniDebugInfoSymbolTable(&symbolOptions)
+		if origErr != nil && miniErr != nil {
+			symTable = nil
+			symErr = fmt.Errorf("o: %s m: %s", origErr.Error(), miniErr.Error())
+		} else {
+			tab := &elf2.SymbolTableWithMiniDebugInfo{
+				Primary:   origSymTable,
+				MiniDebug: miniSymTable,
+			}
+			symTable = tab
+			symErr = nil
+		}
+	}
+
 	if symErr != nil && goErr != nil {
-		return nil, fmt.Errorf("s: %s g: %s", symErr.Error(), goErr.Error())
+		return nil, fmt.Errorf("s: {%s} g: {%s}", symErr.Error(), goErr.Error())
 	}
 	if symErr == nil && goErr == nil {
 		return &elf2.GoTableWithFallback{

ebpf/symtab/elf/elf_sym.go

@@ -35,7 +35,7 @@ type SymbolsOptions struct {
 }
 
 // todo consider using ReaderAt here, same as in gopcln
-func (f *MMapedElfFile) getSymbols(typ elf.SectionType, opt *SymbolsOptions) ([]SymbolIndex, uint32, error) {
+func (f *InMemElfFile) getSymbols(typ elf.SectionType, opt *SymbolsOptions) ([]SymbolIndex, uint32, error) {
 	switch f.Class {
 	case elf.ELFCLASS64:
 		return f.getSymbols64(typ, opt)
@@ -51,7 +51,7 @@ func (f *MMapedElfFile) getSymbols(typ elf.SectionType, opt *SymbolsOptions) ([]
 // if there is no such section in the File.
 var ErrNoSymbols = errors.New("no symbol section")
 
-func (f *MMapedElfFile) getSymbols64(typ elf.SectionType, opt *SymbolsOptions) ([]SymbolIndex, uint32, error) {
+func (f *InMemElfFile) getSymbols64(typ elf.SectionType, opt *SymbolsOptions) ([]SymbolIndex, uint32, error) {
 	symtabSection := f.sectionByType(typ)
 	if symtabSection == nil {
 		return nil, 0, ErrNoSymbols
@@ -108,7 +108,7 @@ func (f *MMapedElfFile) getSymbols64(typ elf.SectionType, opt *SymbolsOptions) (
 	return symbols[:i], symtabSection.Link, nil
 }
 
-func (f *MMapedElfFile) getSymbols32(typ elf.SectionType, opt *SymbolsOptions) ([]SymbolIndex, uint32, error) {
+func (f *InMemElfFile) getSymbols32(typ elf.SectionType, opt *SymbolsOptions) ([]SymbolIndex, uint32, error) {
 	symtabSection := f.sectionByType(typ)
 	if symtabSection == nil {
 		return nil, 0, ErrNoSymbols

ebpf/symtab/elf/elfinmem.go

@@ -0,0 +1,114 @@
+package elf
+
+import (
+	"bytes"
+	"debug/elf"
+	"io"
+	"strings"
+
+	"github.com/ianlancetaylor/demangle"
+)
+
+type ElfSymbolReader interface {
+	getString(start int, demangleOptions []demangle.Option) (string, bool)
+}
+
+type InMemElfFile struct {
+	elf.FileHeader
+	Sections    []elf.SectionHeader
+	Progs       []elf.ProgHeader
+	stringCache map[int]string
+
+	reader io.ReaderAt
+}
+
+func NewInMemElfFile(r io.ReaderAt) (*InMemElfFile, error) {
+	res := &InMemElfFile{
+		reader: r,
+	}
+	elfFile, err := elf.NewFile(res.reader)
+	if err != nil {
+		return nil, err
+	}
+	progs := make([]elf.ProgHeader, 0, len(elfFile.Progs))
+	sections := make([]elf.SectionHeader, 0, len(elfFile.Sections))
+	for i := range elfFile.Progs {
+		progs = append(progs, elfFile.Progs[i].ProgHeader)
+	}
+	for i := range elfFile.Sections {
+		sections = append(sections, elfFile.Sections[i].SectionHeader)
+	}
+	res.FileHeader = elfFile.FileHeader
+	res.Progs = progs
+	res.Sections = sections
+	return res, nil
+}
+
+func (f *InMemElfFile) Clear() {
+	f.stringCache = nil
+	f.Sections = nil
+}
+
+func (f *InMemElfFile) resetReader(r io.ReaderAt) {
+	f.reader = r
+}
+
+func (f *InMemElfFile) Section(name string) *elf.SectionHeader {
+	for i := range f.Sections {
+		s := &f.Sections[i]
+		if s.Name == name {
+			return s
+		}
+	}
+	return nil
+}
+
+func (f *InMemElfFile) sectionByType(typ elf.SectionType) *elf.SectionHeader {
+	for i := range f.Sections {
+		s := &f.Sections[i]
+		if s.Type == typ {
+			return s
+		}
+	}
+	return nil
+}
+
+func (f *InMemElfFile) SectionData(s *elf.SectionHeader) ([]byte, error) {
+	res := make([]byte, s.Size)
+	if _, err := f.reader.ReadAt(res, int64(s.Offset)); err != nil {
+		return nil, err
+	}
+	return res, nil
+}
+
+// getString extracts a string from an ELF string table.
+func (f *InMemElfFile) getString(start int, demangleOptions []demangle.Option) (string, bool) {
+	if s, ok := f.stringCache[start]; ok {
+		return s, true
+	}
+	const tmpBufSize = 128
+	var tmpBuf [tmpBufSize]byte
+	sb := strings.Builder{}
+	for i := 0; i < 10; i++ {
+		_, err := f.reader.ReadAt(tmpBuf[:], int64(start+i*tmpBufSize))
+		if err != nil {
+			return "", false
+		}
+		idx := bytes.IndexByte(tmpBuf[:], 0)
+		if idx >= 0 {
+			sb.Write(tmpBuf[:idx])
+			s := sb.String()
+			if len(demangleOptions) > 0 {
+				s = demangle.Filter(s, demangleOptions...)
+			}
+			if f.stringCache == nil {
+				f.stringCache = make(map[int]string)
+			}
+			f.stringCache[start] = s
+			return s, true
+		} else {
+			sb.Write(tmpBuf[:])
+		}
+	}
+	return "", false
+}

ebpf/symtab/elf/elfmmap.go

@@ -1,26 +1,19 @@
 package elf
 
 import (
-	"bytes"
 	"debug/elf"
 	"fmt"
 	"os"
 	"runtime"
-	"strings"
 
 	"github.com/ianlancetaylor/demangle"
 )
 
 type MMapedElfFile struct {
-	elf.FileHeader
-	Sections []elf.SectionHeader
-	Progs    []elf.ProgHeader
-
+	InMemElfFile
 	fpath string
 	err   error
 	fd    *os.File
-
-	stringCache map[int]string
 }
 
 func NewMMapedElfFile(fpath string) (*MMapedElfFile, error) {
@@ -32,47 +25,15 @@ func NewMMapedElfFile(fpath string) (*MMapedElfFile, error) {
 		res.Close()
 		return nil, err
 	}
-	elfFile, err := elf.NewFile(res.fd)
+	f, err := NewInMemElfFile(res.fd)
 	if err != nil {
 		res.Close()
 		return nil, err
 	}
-	progs := make([]elf.ProgHeader, 0, len(elfFile.Progs))
-	sections := make([]elf.SectionHeader, 0, len(elfFile.Sections))
-	for i := range elfFile.Progs {
-		progs = append(progs, elfFile.Progs[i].ProgHeader)
-	}
-	for i := range elfFile.Sections {
-		sections = append(sections, elfFile.Sections[i].SectionHeader)
-	}
-	res.FileHeader = elfFile.FileHeader
-	res.Progs = progs
-	res.Sections = sections
-
+	res.InMemElfFile = *f
 	runtime.SetFinalizer(res, (*MMapedElfFile).Finalize)
 	return res, nil
 }
-
-func (f *MMapedElfFile) Section(name string) *elf.SectionHeader {
-	for i := range f.Sections {
-		s := &f.Sections[i]
-		if s.Name == name {
-			return s
-		}
-	}
-	return nil
-}
-
-func (f *MMapedElfFile) sectionByType(typ elf.SectionType) *elf.SectionHeader {
-	for i := range f.Sections {
-		s := &f.Sections[i]
-		if s.Type == typ {
-			return s
-		}
-	}
-	return nil
-}
-
 func (f *MMapedElfFile) ensureOpen() error {
 	if f.fd != nil {
 		return nil
@@ -91,8 +52,7 @@ func (f *MMapedElfFile) Close() {
 		f.fd.Close()
 		f.fd = nil
 	}
-	f.stringCache = nil
-	f.Sections = nil
+	f.InMemElfFile.Clear()
 }
 func (f *MMapedElfFile) open() error {
 	if f.err != nil {
@@ -104,18 +64,15 @@ func (f *MMapedElfFile) open() error {
 		return fmt.Errorf("open elf file %s %w", f.fpath, err)
 	}
 	f.fd = fd
+	f.InMemElfFile.resetReader(f.fd)
 	return nil
 }
 
 func (f *MMapedElfFile) SectionData(s *elf.SectionHeader) ([]byte, error) {
 	if err := f.ensureOpen(); err != nil {
 		return nil, err
 	}
-	res := make([]byte, s.Size)
-	if _, err := f.fd.ReadAt(res, int64(s.Offset)); err != nil {
-		return nil, err
-	}
-	return res, nil
+	return f.InMemElfFile.SectionData(s)
 }
 
 func (f *MMapedElfFile) FilePath() string {
@@ -127,32 +84,5 @@ func (f *MMapedElfFile) getString(start int, demangleOptions []demangle.Option)
 	if err := f.ensureOpen(); err != nil {
 		return "", false
 	}
-	if s, ok := f.stringCache[start]; ok {
-		return s, true
-	}
-	const tmpBufSize = 128
-	var tmpBuf [tmpBufSize]byte
-	sb := strings.Builder{}
-	for i := 0; i < 10; i++ {
-		_, err := f.fd.ReadAt(tmpBuf[:], int64(start+i*tmpBufSize))
-		if err != nil {
-			return "", false
-		}
-		idx := bytes.IndexByte(tmpBuf[:], 0)
-		if idx >= 0 {
-			sb.Write(tmpBuf[:idx])
-			s := sb.String()
-			if len(demangleOptions) > 0 {
-				s = demangle.Filter(s, demangleOptions...)
-			}
-			if f.stringCache == nil {
-				f.stringCache = make(map[int]string)
-			}
-			f.stringCache[start] = s
-			return s, true
-		} else {
-			sb.Write(tmpBuf[:])
-		}
-	}
-	return "", false
+	return f.InMemElfFile.getString(start, demangleOptions)
 }