support stripped binaries built wit CGO_ENABLED

CHANGELOG.md

@@ -35,6 +35,7 @@ OpenTelemetry Go Automatic Instrumentation adheres to [Semantic Versioning](http
 ### Fixed
 
 - Respect `OTEL_EXPORTER_OTLP_PROTOCOL` when `OTEL_TRACES_EXPORTER` is not set. ([#1572](https://github.com/open-telemetry/opentelemetry-go-instrumentation/pull/1572))
+- Improve support for stripped binaries, including those built with CGO libraries. ([#1641](https://github.com/open-telemetry/opentelemetry-go-instrumentation/pull/1641))
 
 ## [v0.19.0-alpha] - 2024-12-05
 

Makefile

@@ -120,7 +120,7 @@ docker-build:
 docker-build-base:
 	docker buildx build -t $(IMG_NAME_BASE) --target base .
 
-.PHONY: sample-app/nethttp sample-app/gin sample-app/databasesql sample-app/nethttp-custom sample-app/otelglobal sample-app/autosdk sample-app/kafka-go
+.PHONY: sample-app/%
 sample-app/%: LIBRARY=$*
 sample-app/%:
 	if [ -f ./internal/test/e2e/$(LIBRARY)/build.sh ]; then \

internal/pkg/process/binary/funcs_stripped.go

@@ -6,6 +6,7 @@ package binary
 import (
 	"debug/elf"
 	"debug/gosym"
+	"encoding/binary"
 	"fmt"
 )
 
@@ -18,16 +19,21 @@ func FindFunctionsStripped(elfF *elf.File, relevantFuncs map[string]interface{})
 	if err != nil {
 		return nil, err
 	}
-	sec = elfF.Section(".gosymtab")
-	if sec == nil {
-		return nil, fmt.Errorf("%s section not found in target binary, make sure this is a Go application", ".gosymtab")
-	}
-	symTabRaw, err := sec.Data()
-	if err != nil {
-		return nil, err
+
+	// we extract the `textStart` value based on the header of the pclntab,
+	// this is used to parse the line number table, and is not necessarily the start of the `.text` section.
+	// when a binary is build with C code, the value of `textStart` is not the same as the start of the `.text` section.
+	// https://github.com/golang/go/blob/master/src/runtime/symtab.go#L374
+	var runtimeText uint64
+	ptrSize := uint32(pclndat[7])
+	if ptrSize == 4 {
+		runtimeText = uint64(binary.LittleEndian.Uint32(pclndat[8+2*ptrSize:]))
+	} else {
+		runtimeText = binary.LittleEndian.Uint64(pclndat[8+2*ptrSize:])
 	}
-	pcln := gosym.NewLineTable(pclndat, elfF.Section(".text").Addr)
-	symTab, err := gosym.NewTable(symTabRaw, pcln)
+
+	pcln := gosym.NewLineTable(pclndat, runtimeText)
+	symTab, err := gosym.NewTable(nil, pcln)
 	if err != nil {
 		return nil, err
 	}
@@ -54,34 +60,45 @@ func FindFunctionsStripped(elfF *elf.File, relevantFuncs map[string]interface{})
 }
 
 func findFuncOffsetStripped(f *gosym.Func, elfF *elf.File) (uint64, []uint64, error) {
+	text := elfF.Section(".text")
+	if text == nil {
+		return 0, nil, fmt.Errorf(".text section not found in target binary")
+	}
+
+	var off uint64
+	funcLen := f.End - f.Entry
+	data := make([]byte, funcLen)
+
+	_, err := text.ReadAt(data, int64(f.Entry-text.Addr))
+	if err != nil {
+		return 0, nil, err
+	}
+
+	retInstructionOffsets, err := findRetInstructions(data)
+	if err != nil {
+		return 0, nil, err
+	}
+
 	for _, prog := range elfF.Progs {
 		if prog.Type != elf.PT_LOAD || (prog.Flags&elf.PF_X) == 0 {
 			continue
 		}
 
 		// For more info on this calculation: stackoverflow.com/a/40249502
 		if prog.Vaddr <= f.Value && f.Value < (prog.Vaddr+prog.Memsz) {
-			off := f.Value - prog.Vaddr + prog.Off
-
-			funcLen := f.End - f.Entry
-			data := make([]byte, funcLen)
-			_, err := prog.ReadAt(data, int64(f.Value-prog.Vaddr))
-			if err != nil {
-				return 0, nil, err
-			}
-
-			instructionIndices, err := findRetInstructions(data)
-			if err != nil {
-				return 0, nil, err
-			}
+			off = f.Value - prog.Vaddr + prog.Off
+			break
+		}
+	}
 
-			newLocations := make([]uint64, len(instructionIndices))
-			for i, instructionIndex := range instructionIndices {
-				newLocations[i] = instructionIndex + off
-			}
+	if off == 0 {
+		return 0, nil, fmt.Errorf("could not find function offset")
+	}
 
-			return off, newLocations, nil
-		}
+	retOffsets := make([]uint64, len(retInstructionOffsets))
+	for i, instructionOffset := range retInstructionOffsets {
+		retOffsets[i] = instructionOffset + off
 	}
-	return 0, nil, fmt.Errorf("prog not found")
+
+	return off, retOffsets, nil
 }