From 713ee5cd64540f1721176b2ff3b94cbb141f113f Mon Sep 17 00:00:00 2001
From: CyberRoute <alessandro.bresciani2016@gmail.com>
Date: Thu, 15 Feb 2024 16:49:32 +0100
Subject: [PATCH] file reader pattern, credits for this to @evilsocket

---
 cmd/bruter/main.go        | 21 ++++++++---------
 pkg/fuzzer/reader.go      | 49 +++++++++++++++++++++++++++++++++++++++
 pkg/fuzzer/reader_test.go | 46 ++++++++++++++++++++++++++++++++++++
 3 files changed, 105 insertions(+), 11 deletions(-)
 create mode 100644 pkg/fuzzer/reader.go
 create mode 100644 pkg/fuzzer/reader_test.go

diff --git a/cmd/bruter/main.go b/cmd/bruter/main.go
index a807118..590b3f1 100644
--- a/cmd/bruter/main.go
+++ b/cmd/bruter/main.go
@@ -108,10 +108,18 @@ func main() {
 	}
 	defer file.Close()
 
-	list := readDictionary(file)
+	linesChan, _, err := fuzzer.Reader(file.Name(), 0)
+	if err != nil {
+		log.Fatal().Err(err).Msg("")
+	}
+
+	list := make([]string, 0)
+	for line := range linesChan {
+		list = append(list, line)
+	}
+
 	total := len(list)
 	shift := 1
-
 	queue := createQueue(&app.Mu, *Domain, list, shift, total, *Verbose)
 
 	queue.WaitDone()
@@ -120,15 +128,6 @@ func main() {
 	select {}
 }
 
-func readDictionary(file *os.File) []string {
-	buffer := make([]byte, 500000) // 500K (almost)
-	EOB, err := file.Read(buffer)
-	if err != nil {
-		log.Fatal().Err(err).Msg("")
-	}
-	return strings.Split(string(buffer[:EOB]), "\n")
-}
-
 func createQueue(mu *sync.Mutex, domain string, list []string, shift, total int, verbose bool) *async.WorkQueue {
 	queue := async.NewQueue(*Workers, func(arg async.Job) {
 		ctx := arg.(*workerContext)
diff --git a/pkg/fuzzer/reader.go b/pkg/fuzzer/reader.go
new file mode 100644
index 0000000..e76bffc
--- /dev/null
+++ b/pkg/fuzzer/reader.go
@@ -0,0 +1,49 @@
+package fuzzer
+
+import (
+	"bufio"
+	"io"
+	"os"
+)
+
+func Reader(filename string, noff int64) (chan string, int64, error) {
+	fp, err := os.Open(filename)
+	if err != nil {
+		return nil, 0, err
+	}
+
+	// if offset defined then start from there
+	if noff > 0 {
+		// and go to the start of the line
+		b := make([]byte, 1)
+		for b[0] != '\n' {
+			noff--
+			if _, err := fp.Seek(noff, io.SeekStart); err != nil {
+				fp.Close()
+				return nil, 0, err
+			}
+			if _, err := fp.Read(b); err != nil {
+				fp.Close()
+				return nil, 0, err
+			}
+		}
+		noff++
+	}
+
+	out := make(chan string)
+	go func() {
+		defer fp.Close()
+		defer close(out)
+		scanner := bufio.NewScanner(fp)
+		scanner.Split(bufio.ScanLines)
+		for scanner.Scan() {
+			if _, err := fp.Seek(0, io.SeekCurrent); err != nil {
+				return // Stop reading and return if seeking fails
+			}
+			out <- scanner.Text()
+			noff += int64(len(scanner.Bytes()) + 1) // Update noff
+		}
+	}()
+
+	return out, noff, nil
+}
diff --git a/pkg/fuzzer/reader_test.go b/pkg/fuzzer/reader_test.go
new file mode 100644
index 0000000..5dc8ccb
--- /dev/null
+++ b/pkg/fuzzer/reader_test.go
@@ -0,0 +1,46 @@
+package fuzzer_test
+
+import (
+	"os"
+	"reflect"
+	"testing"
+
+	"github.com/CyberRoute/bruter/pkg/fuzzer"
+)
+
+func TestReader(t *testing.T) {
+	// Create a temporary file with some content
+	tmpfile, err := os.CreateTemp("", "example")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(tmpfile.Name()) // Clean up the file
+
+	// Write some content to the file
+	content := "line1\nline2\nline3\n"
+	if _, err := tmpfile.WriteString(content); err != nil {
+		t.Fatal(err)
+	}
+	tmpfile.Close()
+
+	// Test the Reader function with default offset (0)
+	ch, offset, err := fuzzer.Reader(tmpfile.Name(), 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if offset != 0 {
+		t.Errorf("Expected default offset should be %d", offset)
+	}
+
+	// Read all lines from the channel into a slice
+	var lines []string
+	for line := range ch {
+		lines = append(lines, line)
+	}
+
+	// Verify the lines read from the channel
+	expectedLines := []string{"line1", "line2", "line3"}
+	if !reflect.DeepEqual(lines, expectedLines) {
+		t.Errorf("Expected lines %v, got %v", expectedLines, lines)
+	}
+}