Nmap error handling (#21)

internal/slices/unique_string.go

@@ -0,0 +1,16 @@
+package slices
+
+// Adapted from
+// https://siongui.github.io/2018/04/14/go-remove-duplicates-from-slice-or-array/
+// RemoveDuplicatesFromStringSlice
+func RemoveDuplicatesFromStringSlice(s []string) []string {
+	m := make(map[string]struct{})
+	var result []string
+	for _, item := range s {
+		if _, ok := m[item]; !ok {
+			m[item] = struct{}{}
+			result = append(result, item)
+		}
+	}
+	return result
+}

nmap.go

@@ -4,11 +4,12 @@ package nmap
 import (
 	"bytes"
 	"context"
-	"errors"
 	"fmt"
 	"os/exec"
 	"strings"
 	"time"
+
+	. "github.com/Ullaakut/nmap/internal/slices"
 )
 
 // ScanRunner represents something that can run a scan.
@@ -83,15 +84,20 @@ func (s *Scanner) Run() (*Run, error) {
 		return nil, ErrScanTimeout
 	case <-done:
 		// Scan finished before timeout.
+		var nmapErrors []string
 		if stderr.Len() > 0 {
-			return nil, errors.New(strings.Trim(stderr.String(), ".\n"))
+			// List all unique errors returned by nmap.
+			nmapErrors = strings.Split(strings.Trim(stderr.String(), "\n"), "\n")
+			nmapErrors = RemoveDuplicatesFromStringSlice(nmapErrors)
 		}
 
 		result, err := Parse(stdout.Bytes())
 		if err != nil {
 			return nil, fmt.Errorf("unable to parse nmap output: %v", err)
 		}
 
+		result.NmapErrors = nmapErrors
+
 		// Call filters if they are set.
 		if s.portFilter != nil {
 			result = choosePorts(result, s.portFilter)

nmap_test.go

@@ -10,6 +10,9 @@ import (
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestNmapNotInstalled(t *testing.T) {
@@ -44,6 +47,7 @@ func TestRun(t *testing.T) {
 
 		expectedResult *Run
 		expectedErr    error
+		expectedNmapErr string
 	}{
 		{
 			description: "invalid binary path",
@@ -99,7 +103,11 @@ func TestRun(t *testing.T) {
 				WithTimingTemplate(TimingFastest),
 			},
 
-			expectedErr: errors.New("WARNING: No targets were specified, so 0 hosts scanned"),
+			expectedNmapErr: "WARNING: No targets were specified, so 0 hosts scanned.",
+			expectedResult: &Run{
+				Scanner: "nmap",
+				Args: "/usr/local/bin/nmap -T5 -oX -",
+			},
 		},
 		{
 			description: "scan localhost with filters",
@@ -174,12 +182,21 @@ func TestRun(t *testing.T) {
 			}
 
 			result, err := s.Run()
+
 			if err != test.expectedErr {
+				require.NotNil(t, err)
+
 				if err.Error() != test.expectedErr.Error() {
 					t.Errorf("expected error %q got %q", test.expectedErr, err)
 				}
 			}
 
+			if test.expectedNmapErr != "" {
+				require.NotNil(t, result)
+
+				assert.Contains(t, result.NmapErrors, test.expectedNmapErr)
+			}
+
 			if result == nil && test.expectedResult == nil {
 				return
 			} else if result == nil && test.expectedResult != nil {

xml.go

@@ -32,7 +32,8 @@ type Run struct {
 	TaskProgress     []TaskProgress `xml:"taskprogress" json:"task_progress"`
 	TaskEnd          []Task         `xml:"taskend" json:"task_end"`
 
-	rawXML []byte
+	NmapErrors []string
+	rawXML     []byte
 }
 
 // ToFile writes a Run as XML into the specified file path.
@@ -420,7 +421,7 @@ func (t *Timestamp) UnmarshalXMLAttr(attr xml.Attr) (err error) {
 // Run struct.
 func Parse(content []byte) (*Run, error) {
 	r := &Run{
-		rawXML: content,
+		rawXML:     content,
 	}
 
 	err := xml.Unmarshal(content, r)

xml_test.go

@@ -1,7 +1,6 @@
 package nmap
 
 import (
-	"bufio"
 	"bytes"
 	"encoding/json"
 	"encoding/xml"
@@ -173,12 +172,6 @@ func TestParseTableXML(t *testing.T) {
 	}
 }
 
-type mockWriter struct {
-	wr       *bufio.Writer
-	writeErr error
-	flushErr error
-}
-
 func TestFormatTableXML(t *testing.T) {
 	table := Table{
 		Key: "key123",
@@ -1069,7 +1062,9 @@ func TestParseRunXML(t *testing.T) {
 			result, err := Parse(rawXML)
 
 			// Remove rawXML before comparing
-			result.rawXML = []byte{}
+			if result != nil {
+				result.rawXML = []byte{}
+			}
 
 			compareResults(t, test.expectedResult, result)