Replace Analyzer with NewInfo function (#1941)

* Add NewInfo to process pkg

Replace the Analyze method of the Analyzer with the new function.

* Rename process/analyze.go to info.go

* Remove unneeded process Analyzer

Author: MrAlias

internal/pkg/instrumentation/manager.go

@@ -74,10 +74,8 @@ func NewManager(logger *slog.Logger, otelController *opentelemetry.Controller, p
 		}
 	}
 
-	pa := process.NewAnalyzer(logger, pid)
-
 	var err error
-	m.proc, err = pa.Analyze(funcs)
+	m.proc, err = process.NewInfo(pid, funcs)
 	if err != nil {
 		return nil, err
 	}

internal/pkg/process/analyze.go

@@ -0,0 +1,120 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package process
+
+import (
+	"debug/elf"
+	"errors"
+	"fmt"
+	"runtime/debug"
+
+	"github.com/Masterminds/semver/v3"
+
+	"go.opentelemetry.io/auto/internal/pkg/process/binary"
+)
+
+// Info are the details about a target process.
+type Info struct {
+	ID         ID
+	Functions  []*binary.Func
+	GoVersion  *semver.Version
+	Modules    map[string]*semver.Version
+	Allocation *Allocation
+}
+
+// NewInfo returns a new Info with information about the process identified by
+// id. The functions of the returned Info are filtered by relevantFuncs.
+//
+// A partial Info and error may be returned for dependencies that cannot be
+// parsed.
+func NewInfo(id ID, relevantFuncs map[string]interface{}) (*Info, error) {
+	elfF, err := elf.Open(id.ExePath())
+	if err != nil {
+		return nil, err
+	}
+	defer elfF.Close()
+
+	bi, err := id.BuildInfo()
+	if err != nil {
+		return nil, err
+	}
+
+	goVersion, err := semver.NewVersion(bi.GoVersion)
+	if err != nil {
+		return nil, err
+	}
+
+	result := &Info{
+		ID:        id,
+		GoVersion: goVersion,
+	}
+
+	result.Functions, err = findFunctions(elfF, relevantFuncs)
+	if err != nil {
+		return nil, err
+	}
+
+	result.Modules, err = findModules(goVersion, bi.Deps)
+	return result, err
+}
+
+func findModules(goVer *semver.Version, deps []*debug.Module) (map[string]*semver.Version, error) {
+	var err error
+	out := make(map[string]*semver.Version, len(deps)+1)
+	for _, dep := range deps {
+		depVersion, e := semver.NewVersion(dep.Version)
+		if e != nil {
+			err = errors.Join(
+				err,
+				fmt.Errorf("invalid dependency version %s (%s): %w", dep.Path, dep.Version, e),
+			)
+			continue
+		}
+		out[dep.Path] = depVersion
+	}
+	out["std"] = goVer
+	return out, err
+}
+
+func findFunctions(elfF *elf.File, relevantFuncs map[string]interface{}) ([]*binary.Func, error) {
+	found, err := binary.FindFunctionsUnStripped(elfF, relevantFuncs)
+	if err != nil {
+		if !errors.Is(err, elf.ErrNoSymbols) {
+			return nil, err
+		}
+		found, err = binary.FindFunctionsStripped(elfF, relevantFuncs)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if len(found) == 0 {
+		return nil, errors.New("no functions found")
+	}
+
+	return found, nil
+}
+
+// GetFunctionOffset returns the offset for of the function with name.
+func (i *Info) GetFunctionOffset(name string) (uint64, error) {
+	for _, f := range i.Functions {
+		if f.Name == name {
+			return f.Offset, nil
+		}
+	}
+
+	return 0, fmt.Errorf("could not find offset for function %s", name)
+}
+
+// GetFunctionReturns returns the return value of the call for the function
+// with name.
+func (i *Info) GetFunctionReturns(name string) ([]uint64, error) {
+	for _, f := range i.Functions {
+		if f.Name == name {
+			return f.ReturnOffsets, nil
+		}
+	}
+
+	return nil, fmt.Errorf("could not find returns for function %s", name)
+}