feat: add nodejs-binary package classifier (#1296)

syft/pkg/cataloger/generic/classifier.go

@@ -0,0 +1,87 @@
+package generic
+
+import (
+	"fmt"
+	"io"
+	"path"
+	"regexp"
+
+	"github.com/anchore/syft/internal"
+	"github.com/anchore/syft/syft/artifact"
+	"github.com/anchore/syft/syft/file"
+	"github.com/anchore/syft/syft/pkg"
+	"github.com/anchore/syft/syft/pkg/cataloger/internal/unionreader"
+	"github.com/anchore/syft/syft/source"
+)
+
+// Classifier is a generic package classifier that can be used to match a package definition
+// to a file that meets the given content criteria of the EvidencePatternTemplates.
+type Classifier struct {
+	Package string
+	// FilepathPatterns is a list of regular expressions that will be used to match against the file path of a given
+	// source location. If any of the patterns match, the file will be considered a candidate for parsing.
+	// If no patterns are provided, the reader is automatically considered a candidate.
+	FilepathPatterns []*regexp.Regexp
+	// EvidencePattern is a list of regular expressions that will be used to match against the file contents of a
+	// given file in the source location. If any of the patterns match, the file will be considered a candidate for parsing.
+	EvidencePatterns []*regexp.Regexp
+	// CPE is the CPE we want to match against
+	CPEs []pkg.CPE
+}
+
+func (c Classifier) Examine(reader source.LocationReadCloser) (p *pkg.Package, r *artifact.Relationship, err error) {
+	doesFilepathMatch := true
+	if len(c.FilepathPatterns) > 0 {
+		doesFilepathMatch, _ = file.FilepathMatches(c.FilepathPatterns, reader.Location)
+	}
+
+	if !doesFilepathMatch {
+		return nil, nil, fmt.Errorf("location: %s did not match any patterns for package=%q", reader.Location, c.Package)
+	}
+
+	contents, err := getContents(reader)
+	if err != nil {
+		return nil, nil, fmt.Errorf("unable to get read contents for file: %+v", err)
+	}
+
+	var classifiedPackage *pkg.Package
+	for _, patternTemplate := range c.EvidencePatterns {
+		if !patternTemplate.Match(contents) {
+			continue
+		}
+
+		matchMetadata := internal.MatchNamedCaptureGroups(patternTemplate, string(contents))
+		if classifiedPackage == nil {
+			classifiedPackage = &pkg.Package{
+				Name:         path.Base(reader.VirtualPath),
+				Version:      matchMetadata["version"],
+				Language:     pkg.Binary,
+				Locations:    source.NewLocationSet(reader.Location),
+				Type:         pkg.BinaryPkg,
+				CPEs:         c.CPEs,
+				MetadataType: pkg.BinaryMetadataType,
+				Metadata: pkg.BinaryMetadata{
+					Classifier:  c.Package,
+					RealPath:    reader.RealPath,
+					VirtualPath: reader.VirtualPath,
+				},
+			}
+			break
+		}
+	}
+	return classifiedPackage, nil, nil
+}
+
+func getContents(reader source.LocationReadCloser) ([]byte, error) {
+	unionReader, err := unionreader.GetUnionReader(reader.ReadCloser)
+	if err != nil {
+		return nil, fmt.Errorf("unable to get union reader for file: %+v", err)
+	}
+
+	contents, err := io.ReadAll(unionReader)
+	if err != nil {
+		return nil, fmt.Errorf("unable to get contents for file: %+v", err)
+	}
+
+	return contents, nil
+}