Drop more unused code

libpf/convenience.go

@@ -5,34 +5,14 @@ package libpf // import "go.opentelemetry.io/ebpf-profiler/libpf"
 
 import (
 	"context"
-	"fmt"
 	"math/rand/v2"
-	"os"
 	"reflect"
 	"time"
 	"unsafe"
 
 	log "github.com/sirupsen/logrus"
 )
 
-// WriteTempFile writes a data buffer to a temporary file on the filesystem. It
-// is the callers responsibility to clean up that file again. The function returns
-// the filename if successful.
-func WriteTempFile(data []byte, directory, prefix string) (string, error) {
-	file, err := os.CreateTemp(directory, prefix)
-	if err != nil {
-		return "", err
-	}
-	defer file.Close()
-	if _, err := file.Write(data); err != nil {
-		return "", fmt.Errorf("failed to write data to temporary file: %w", err)
-	}
-	if err := file.Sync(); err != nil {
-		return "", fmt.Errorf("failed to synchronize file data: %w", err)
-	}
-	return file.Name(), nil
-}
-
 // SleepWithJitter sleeps for baseDuration +/- jitter (jitter is [0..1])
 func SleepWithJitter(baseDuration time.Duration, jitter float64) {
 	time.Sleep(AddJitter(baseDuration, jitter))

libpf/pfelf/pfelf.go

@@ -20,24 +20,6 @@ import (
 	"go.opentelemetry.io/ebpf-profiler/libpf"
 )
 
-// SafeOpenELF opens the given ELF file in a safely way in that
-// it recovers from panics inside elf.Open().
-// Under circumstances we see fatal errors from inside the runtime, which
-// are not recoverable, e.g. "fatal error: runtime: out of memory".
-func SafeOpenELF(name string) (elfFile *elf.File, err error) {
-	defer func() {
-		// debug/elf has issues with malformed ELF files
-		if r := recover(); r != nil {
-			if elfFile != nil {
-				elfFile.Close()
-				elfFile = nil
-			}
-			err = fmt.Errorf("failed to open ELF file (recovered from panic): %s", name)
-		}
-	}()
-	return elf.Open(name)
-}
-
 // HasDWARFData returns true if the provided ELF file contains actionable DWARF debugging
 // information.
 // This function does not call `elfFile.DWARF()` on purpose, as it can be extremely expensive in
@@ -132,41 +114,6 @@ func GetDebugLink(elfFile *elf.File) (linkName string, crc32 int32, err error) {
 	return ParseDebugLink(sectionData)
 }
 
-// GetDebugAltLink returns the contents of the `.gnu_debugaltlink` section (path and build
-// ID). If no link is present, ErrNoDebugLink is returned.
-func GetDebugAltLink(elfFile *elf.File) (fileName, buildID string, err error) {
-	// The .gnu_debugaltlink section is not always present
-	sectionData, err := getSectionData(elfFile, ".gnu_debugaltlink")
-	if err != nil {
-		return "", "", ErrNoDebugLink
-	}
-
-	// The whole .gnu_debugaltlink section consists of:
-	// 1) path to target (variable-length string)
-	// 2) null character separator (1 byte)
-	// 3) build ID (usually 20 bytes, but can vary)
-	//
-	// First, find the position of the null character:
-	nullCharIdx := bytes.IndexByte(sectionData, 0)
-	if nullCharIdx == -1 {
-		return "", "", nil
-	}
-
-	// The path consists of all the characters before the first null character
-	path := strings.ToValidUTF8(string(sectionData[:nullCharIdx]), "")
-
-	// Check that we can read a build ID: there should be at least 1 byte after the null character.
-	if nullCharIdx+1 == len(sectionData) {
-		return "", "", errors.New("malformed .gnu_debugaltlink section (missing build ID)")
-	}
-
-	// The build ID consists of all the bytes after the first null character
-	buildIDBytes := sectionData[nullCharIdx+1:]
-	buildID = hex.EncodeToString(buildIDBytes)
-
-	return path, buildID, nil
-}
-
 var ErrNoBuildID = errors.New("no build ID")
 var ubuntuKernelSignature = regexp.MustCompile(` \(Ubuntu[^)]*\)\n$`)
 
@@ -303,32 +250,6 @@ func getNoteHexString(sectionBytes []byte, name string, noteType uint32) (
 	return hex.EncodeToString(sectionBytes[idxDataStart:idxDataEnd]), true, nil
 }
 
-// GetLinuxBuildSalt extracts the linux kernel build salt from the provided ELF path.
-// It is read from the .notes ELF section.
-// It should be present in both kernel modules and the kernel image of most distro-vended kernel
-// packages, and should be identical across all the files: kernel modules will have the same salt
-// as their corresponding vmlinux image if they were built at the same time.
-// This can be used to identify the kernel image corresponding to a module.
-// See https://lkml.org/lkml/2018/7/3/1156
-func GetLinuxBuildSalt(filePath string) (salt string, found bool, err error) {
-	elfFile, err := SafeOpenELF(filePath)
-	if err != nil {
-		return "", false, fmt.Errorf("could not open %s: %w", filePath, err)
-	}
-	defer elfFile.Close()
-
-	sectionData, err := getSectionData(elfFile, ".note.Linux")
-	if err != nil {
-		sectionData, err = getSectionData(elfFile, ".notes")
-		if err != nil {
-			return "", false, nil
-		}
-	}
-
-	// 0x100 is defined as LINUX_ELFNOTE_BUILD_SALT in include/linux/build-salt.h
-	return getNoteHexString(sectionData, "Linux", 0x100)
-}
-
 func symbolMapFromELFSymbols(syms []elf.Symbol) *libpf.SymbolMap {
 	symmap := &libpf.SymbolMap{}
 	for _, sym := range syms {
@@ -342,16 +263,6 @@ func symbolMapFromELFSymbols(syms []elf.Symbol) *libpf.SymbolMap {
 	return symmap
 }
 
-// GetSymbols gets the symbols of elf.File and returns them as libpf.SymbolMap for
-// fast lookup by address and name.
-func GetSymbols(elfFile *elf.File) (*libpf.SymbolMap, error) {
-	syms, err := elfFile.Symbols()
-	if err != nil {
-		return nil, err
-	}
-	return symbolMapFromELFSymbols(syms), nil
-}
-
 // GetDynamicSymbols gets the dynamic symbols of elf.File and returns them as libpf.SymbolMap for
 // fast lookup by address and name.
 func GetDynamicSymbols(elfFile *elf.File) (*libpf.SymbolMap, error) {
@@ -362,43 +273,6 @@ func GetDynamicSymbols(elfFile *elf.File) (*libpf.SymbolMap, error) {
 	return symbolMapFromELFSymbols(syms), nil
 }
 
-// IsKernelModule returns true if the provided ELF file looks like a kernel module (an ELF with a
-// .modinfo and .gnu.linkonce.this_module sections).
-func IsKernelModule(file *elf.File) (bool, error) {
-	sectionFound, err := HasSection(file, ".modinfo")
-	if err != nil {
-		return false, err
-	}
-
-	if !sectionFound {
-		return false, nil
-	}
-
-	return HasSection(file, ".gnu.linkonce.this_module")
-}
-
-// IsKernelImage returns true if the provided ELF file looks like a kernel image (an ELF with a
-// __modver section).
-func IsKernelImage(file *elf.File) (bool, error) {
-	return HasSection(file, "__modver")
-}
-
-// IsKernelFile returns true if the provided ELF file looks like a kernel file (either a kernel
-// image or a kernel module).
-func IsKernelFile(file *elf.File) (bool, error) {
-	isModule, err := IsKernelImage(file)
-	if err != nil {
-		return false, err
-	}
-
-	isImage, err := IsKernelModule(file)
-	if err != nil {
-		return false, err
-	}
-
-	return isModule || isImage, nil
-}
-
 // IsGoBinary returns true if the provided file is a Go binary (= an ELF file with
 // a known Golang section).
 func IsGoBinary(file *elf.File) (bool, error) {

libpf/tracehash.go

@@ -28,15 +28,6 @@ func TraceHashFromBytes(b []byte) (TraceHash, error) {
 	return TraceHash{h}, nil
 }
 
-// TraceHashFromString parses a byte slice of a trace hash into the internal data representation.
-func TraceHashFromString(s string) (TraceHash, error) {
-	h, err := basehash.New128FromString(s)
-	if err != nil {
-		return TraceHash{}, err
-	}
-	return TraceHash{h}, nil
-}
-
 func (h TraceHash) Equal(other TraceHash) bool {
 	return h.Hash128.Equal(other.Hash128)
 }

stringutil/stringutil.go

@@ -84,8 +84,3 @@ func SplitN(s, sep string, f []string) int {
 func ByteSlice2String(b []byte) string {
 	return *(*string)(unsafe.Pointer(&b))
 }
-
-// StrDataPtr returns the string's underlying Data pointer through reflection.
-func StrDataPtr(s string) *byte {
-	return unsafe.StringData(s)
-}