diff --git a/internal/api/handlers/management/logs.go b/internal/api/handlers/management/logs.go
index ca6d7eda..5e4de2dd 100644
--- a/internal/api/handlers/management/logs.go
+++ b/internal/api/handlers/management/logs.go
@@ -2,7 +2,11 @@ package management
 
 import (
 	"bufio"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/json"
 	"fmt"
+	"io"
 	"math"
 	"net/http"
 	"os"
@@ -20,6 +24,8 @@ const (
 	defaultLogFileName      = "main.log"
 	logScannerInitialBuffer = 64 * 1024
 	logScannerMaxBuffer     = 8 * 1024 * 1024
+	logCursorVersion        = 1
+	logCursorFingerprintMax = 4 * 1024
 )
 
 // GetLogs returns log lines with optional incremental loading.
@@ -475,6 +481,299 @@ func (acc *logAccumulator) result() ([]string, int, int64) {
 	return acc.lines, acc.total, acc.latest
 }
 
+type logCursor struct {
+	Version         int    `json:"v"`
+	File            string `json:"file"`
+	Offset          int64  `json:"offset"`
+	Size            int64  `json:"size"`
+	ModTime         int64  `json:"modTime"`
+	LatestTimestamp int64  `json:"latestTimestamp"`
+	Fingerprint     string `json:"fingerprint"`
+}
+
+type completeLogRead struct {
+	lines     []string
+	endOffset int64
+	latest    int64
+	hitLimit  bool
+}
+
+func encodeLogCursor(cursor logCursor) (string, error) {
+	raw, err := json.Marshal(cursor)
+	if err != nil {
+		return "", err
+	}
+	return base64.RawURLEncoding.EncodeToString(raw), nil
+}
+
+func decodeLogCursor(raw string) (logCursor, error) {
+	value := strings.TrimSpace(raw)
+	if value == "" {
+		return logCursor{}, fmt.Errorf("empty cursor")
+	}
+	data, err := base64.RawURLEncoding.DecodeString(value)
+	if err != nil {
+		data, err = base64.URLEncoding.DecodeString(value)
+	}
+	if err != nil {
+		return logCursor{}, fmt.Errorf("invalid cursor encoding")
+	}
+	var cursor logCursor
+	if errUnmarshal := json.Unmarshal(data, &cursor); errUnmarshal != nil {
+		return logCursor{}, fmt.Errorf("invalid cursor payload")
+	}
+	if errValidate := validateLogCursor(cursor); errValidate != nil {
+		return logCursor{}, errValidate
+	}
+	return cursor, nil
+}
+
+func validateLogCursor(cursor logCursor) error {
+	if cursor.Version != logCursorVersion {
+		return fmt.Errorf("unsupported cursor version")
+	}
+	if !isAllowedLogCursorFile(cursor.File) {
+		return fmt.Errorf("invalid cursor file")
+	}
+	if cursor.Offset < 0 || cursor.Size < 0 || cursor.ModTime < 0 || cursor.LatestTimestamp < 0 {
+		return fmt.Errorf("invalid cursor position")
+	}
+	if strings.TrimSpace(cursor.Fingerprint) == "" {
+		return fmt.Errorf("invalid cursor fingerprint")
+	}
+	return nil
+}
+
+func isAllowedLogCursorFile(name string) bool {
+	if name == "" || name == "." || name == ".." {
+		return false
+	}
+	if strings.ContainsAny(name, `/\`) {
+		return false
+	}
+	if filepath.Base(name) != name {
+		return false
+	}
+	return name == defaultLogFileName || isRotatedLogFile(name)
+}
+
+func safeLogFilePath(logDir, name string) (string, error) {
+	if !isAllowedLogCursorFile(name) {
+		return "", fmt.Errorf("invalid log file")
+	}
+	dirAbs, errAbs := filepath.Abs(logDir)
+	if errAbs != nil {
+		return "", fmt.Errorf("resolve log directory: %w", errAbs)
+	}
+	dirAbs = filepath.Clean(dirAbs)
+	fullPath := filepath.Clean(filepath.Join(dirAbs, name))
+	rel, errRel := filepath.Rel(dirAbs, fullPath)
+	if errRel != nil {
+		return "", fmt.Errorf("resolve log file: %w", errRel)
+	}
+	if rel == "." || strings.HasPrefix(rel, ".."+string(os.PathSeparator)) || rel == ".." || filepath.IsAbs(rel) {
+		return "", fmt.Errorf("invalid log file")
+	}
+	return fullPath, nil
+}
+
+func newLogCursor(path string, offset, latest int64) (string, error) {
+	info, errStat := os.Stat(path)
+	if errStat != nil {
+		return "", errStat
+	}
+	if info.IsDir() {
+		return "", fmt.Errorf("invalid log file")
+	}
+	if offset < 0 || offset > info.Size() {
+		return "", fmt.Errorf("invalid cursor offset")
+	}
+	fingerprint, errFingerprint := logFileFingerprint(path, offset)
+	if errFingerprint != nil {
+		return "", errFingerprint
+	}
+	return encodeLogCursor(logCursor{
+		Version:         logCursorVersion,
+		File:            filepath.Base(path),
+		Offset:          offset,
+		Size:            info.Size(),
+		ModTime:         info.ModTime().Unix(),
+		LatestTimestamp: latest,
+		Fingerprint:     fingerprint,
+	})
+}
+
+func logFileFingerprint(path string, boundary int64) (string, error) {
+	if boundary < 0 {
+		return "", fmt.Errorf("invalid fingerprint boundary")
+	}
+	file, errOpen := os.Open(path)
+	if errOpen != nil {
+		return "", errOpen
+	}
+	defer func() {
+		_ = file.Close()
+	}()
+	info, errStat := file.Stat()
+	if errStat != nil {
+		return "", errStat
+	}
+	if info.IsDir() {
+		return "", fmt.Errorf("invalid log file")
+	}
+	if boundary > info.Size() {
+		return "", fmt.Errorf("invalid fingerprint boundary")
+	}
+
+	hash := sha256.New()
+	_, _ = fmt.Fprintf(hash, "log-cursor-v1:%d:", boundary)
+	firstLen := minInt64(boundary, logCursorFingerprintMax)
+	if errRead := writeFileRange(hash, file, 0, firstLen); errRead != nil {
+		return "", errRead
+	}
+	tailLen := minInt64(boundary, logCursorFingerprintMax)
+	tailStart := boundary - tailLen
+	_, _ = fmt.Fprintf(hash, ":%d:", tailStart)
+	if errRead := writeFileRange(hash, file, tailStart, tailLen); errRead != nil {
+		return "", errRead
+	}
+	sum := hash.Sum(nil)
+	return base64.RawURLEncoding.EncodeToString(sum[:12]), nil
+}
+
+func writeFileRange(dst io.Writer, file *os.File, start, length int64) error {
+	if length <= 0 {
+		return nil
+	}
+	buf := make([]byte, 32*1024)
+	pos := start
+	remaining := length
+	for remaining > 0 {
+		chunk := minInt64(int64(len(buf)), remaining)
+		n, errRead := file.ReadAt(buf[:chunk], pos)
+		if n > 0 {
+			if _, errWrite := dst.Write(buf[:n]); errWrite != nil {
+				return errWrite
+			}
+			pos += int64(n)
+			remaining -= int64(n)
+		}
+		if errRead != nil {
+			if errRead == io.EOF && remaining == 0 {
+				return nil
+			}
+			return errRead
+		}
+	}
+	return nil
+}
+
+func readCompleteLogLines(path string, offset, maxOffset int64, limit int) (completeLogRead, error) {
+	if offset < 0 {
+		return completeLogRead{}, fmt.Errorf("invalid log offset")
+	}
+	file, errOpen := os.Open(path)
+	if errOpen != nil {
+		return completeLogRead{}, errOpen
+	}
+	defer func() {
+		_ = file.Close()
+	}()
+	info, errStat := file.Stat()
+	if errStat != nil {
+		return completeLogRead{}, errStat
+	}
+	if info.IsDir() {
+		return completeLogRead{}, fmt.Errorf("invalid log file")
+	}
+	size := info.Size()
+	if maxOffset < 0 || maxOffset > size {
+		maxOffset = size
+	}
+	if offset > maxOffset {
+		return completeLogRead{}, fmt.Errorf("invalid log offset")
+	}
+
+	reader := bufio.NewReader(io.NewSectionReader(file, offset, maxOffset-offset))
+	result := completeLogRead{
+		lines:     []string{},
+		endOffset: offset,
+	}
+	currentOffset := offset
+	for {
+		raw, errRead := reader.ReadString('\n')
+		if strings.HasSuffix(raw, "\n") {
+			currentOffset += int64(len(raw))
+			line := strings.TrimSuffix(raw, "\n")
+			line = strings.TrimRight(line, "\r")
+			result.lines = append(result.lines, line)
+			result.endOffset = currentOffset
+			if ts := parseTimestamp(line); ts > result.latest {
+				result.latest = ts
+			}
+			if limit > 0 && len(result.lines) >= limit {
+				result.hitLimit = true
+				break
+			}
+			if errRead == nil {
+				continue
+			}
+		}
+		if errRead == io.EOF {
+			break
+		}
+		if errRead != nil {
+			return completeLogRead{}, errRead
+		}
+	}
+	return result, nil
+}
+
+func completeLogBoundary(path string) (int64, error) {
+	file, errOpen := os.Open(path)
+	if errOpen != nil {
+		return 0, errOpen
+	}
+	defer func() {
+		_ = file.Close()
+	}()
+	info, errStat := file.Stat()
+	if errStat != nil {
+		return 0, errStat
+	}
+	if info.IsDir() {
+		return 0, fmt.Errorf("invalid log file")
+	}
+	size := info.Size()
+	if size == 0 {
+		return 0, nil
+	}
+	buf := make([]byte, 32*1024)
+	pos := size
+	for pos > 0 {
+		chunk := minInt64(int64(len(buf)), pos)
+		pos -= chunk
+		n, errRead := file.ReadAt(buf[:chunk], pos)
+		if errRead != nil && errRead != io.EOF {
+			return 0, errRead
+		}
+		if n <= 0 {
+			continue
+		}
+		if idx := strings.LastIndexByte(string(buf[:n]), '\n'); idx >= 0 {
+			return pos + int64(idx) + 1, nil
+		}
+	}
+	return 0, nil
+}
+
+func minInt64(a, b int64) int64 {
+	if a < b {
+		return a
+	}
+	return b
+}
+
 func parseCutoff(raw string) int64 {
 	value := strings.TrimSpace(raw)
 	if value == "" {
diff --git a/internal/api/handlers/management/logs_test.go b/internal/api/handlers/management/logs_test.go
new file mode 100644
index 00000000..4f15f706
--- /dev/null
+++ b/internal/api/handlers/management/logs_test.go
@@ -0,0 +1,136 @@
+package management
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func TestDecodeLogCursorRejectsUnsafeFiles(t *testing.T) {
+	unsafeNames := []string{
+		"",
+		".",
+		"..",
+		"../secret",
+		"nested/main.log",
+		`nested\main.log`,
+		"error.log",
+	}
+
+	for _, name := range unsafeNames {
+		t.Run(name, func(t *testing.T) {
+			raw := mustEncodeRawCursor(t, logCursor{
+				Version:     logCursorVersion,
+				File:        name,
+				Fingerprint: "fingerprint",
+			})
+			if _, err := decodeLogCursor(raw); err == nil {
+				t.Fatalf("decodeLogCursor(%q) succeeded, want error", name)
+			}
+		})
+	}
+
+	for _, name := range []string{defaultLogFileName, defaultLogFileName + ".1", "main-2026-06-15T10-00-00.log"} {
+		t.Run("allowed_"+name, func(t *testing.T) {
+			raw := mustEncodeRawCursor(t, logCursor{
+				Version:     logCursorVersion,
+				File:        name,
+				Fingerprint: "fingerprint",
+			})
+			if _, err := decodeLogCursor(raw); err != nil {
+				t.Fatalf("decodeLogCursor(%q) error = %v", name, err)
+			}
+		})
+	}
+}
+
+func TestLogCursorRoundTripOmitsAbsolutePath(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, defaultLogFileName)
+	if err := os.WriteFile(path, []byte("line one\nline two\n"), 0o644); err != nil {
+		t.Fatalf("write log file: %v", err)
+	}
+
+	boundary, errBoundary := completeLogBoundary(path)
+	if errBoundary != nil {
+		t.Fatalf("completeLogBoundary() error = %v", errBoundary)
+	}
+	raw, errCursor := newLogCursor(path, boundary, 123)
+	if errCursor != nil {
+		t.Fatalf("newLogCursor() error = %v", errCursor)
+	}
+	decoded, errDecode := decodeLogCursor(raw)
+	if errDecode != nil {
+		t.Fatalf("decodeLogCursor() error = %v", errDecode)
+	}
+	if decoded.File != defaultLogFileName {
+		t.Fatalf("cursor file = %q, want %q", decoded.File, defaultLogFileName)
+	}
+	if decoded.Offset != boundary {
+		t.Fatalf("cursor offset = %d, want %d", decoded.Offset, boundary)
+	}
+	if decoded.LatestTimestamp != 123 {
+		t.Fatalf("cursor latest timestamp = %d, want 123", decoded.LatestTimestamp)
+	}
+	if strings.Contains(raw, dir) {
+		t.Fatalf("encoded cursor contains log directory %q: %q", dir, raw)
+	}
+}
+
+func TestReadCompleteLogLinesSkipsTrailingPartial(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, defaultLogFileName)
+	initial := "first\nsecond\r\npartial"
+	if err := os.WriteFile(path, []byte(initial), 0o644); err != nil {
+		t.Fatalf("write log file: %v", err)
+	}
+
+	read, errRead := readCompleteLogLines(path, 0, -1, 0)
+	if errRead != nil {
+		t.Fatalf("readCompleteLogLines() error = %v", errRead)
+	}
+	wantLines := []string{"first", "second"}
+	if !reflect.DeepEqual(read.lines, wantLines) {
+		t.Fatalf("lines = %#v, want %#v", read.lines, wantLines)
+	}
+	wantOffset := int64(len("first\nsecond\r\n"))
+	if read.endOffset != wantOffset {
+		t.Fatalf("endOffset = %d, want %d", read.endOffset, wantOffset)
+	}
+
+	file, errOpen := os.OpenFile(path, os.O_APPEND|os.O_WRONLY, 0)
+	if errOpen != nil {
+		t.Fatalf("open log file: %v", errOpen)
+	}
+	if _, errWrite := file.WriteString("\n"); errWrite != nil {
+		_ = file.Close()
+		t.Fatalf("append newline: %v", errWrite)
+	}
+	if errClose := file.Close(); errClose != nil {
+		t.Fatalf("close log file: %v", errClose)
+	}
+
+	next, errNext := readCompleteLogLines(path, read.endOffset, -1, 0)
+	if errNext != nil {
+		t.Fatalf("readCompleteLogLines() after append error = %v", errNext)
+	}
+	if !reflect.DeepEqual(next.lines, []string{"partial"}) {
+		t.Fatalf("next lines = %#v, want partial", next.lines)
+	}
+	if next.endOffset != int64(len(initial)+1) {
+		t.Fatalf("next endOffset = %d, want %d", next.endOffset, len(initial)+1)
+	}
+}
+
+func mustEncodeRawCursor(t *testing.T, cursor logCursor) string {
+	t.Helper()
+	raw, err := json.Marshal(cursor)
+	if err != nil {
+		t.Fatalf("json.Marshal cursor: %v", err)
+	}
+	return base64.RawURLEncoding.EncodeToString(raw)
+}
-- 
2.51.2


From 95a72a47c8e7f73b58d5b3451ced7b4be9cd977b Mon Sep 17 00:00:00 2001
From: LTbinglingfeng <tan13318527080@163.com>
Date: Mon, 15 Jun 2026 02:08:06 +0800
Subject: [PATCH 02/10] Tail management logs with cursors

---
 internal/api/handlers/management/logs.go      | 167 ++++++++++++++++--
 internal/api/handlers/management/logs_test.go | 122 +++++++++++++
 2 files changed, 277 insertions(+), 12 deletions(-)

diff --git a/internal/api/handlers/management/logs.go b/internal/api/handlers/management/logs.go
index 5e4de2dd..fa3b6cb0 100644
--- a/internal/api/handlers/management/logs.go
+++ b/internal/api/handlers/management/logs.go
@@ -2,9 +2,11 @@ package management
 
 import (
 	"bufio"
+	"bytes"
 	"crypto/sha256"
 	"encoding/base64"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"math"
@@ -53,11 +55,7 @@ func (h *Handler) GetLogs(c *gin.Context) {
 	if err != nil {
 		if os.IsNotExist(err) {
 			cutoff := parseCutoff(c.Query("after"))
-			c.JSON(http.StatusOK, gin.H{
-				"lines":            []string{},
-				"line-count":       0,
-				"latest-timestamp": cutoff,
-			})
+			writeLogsResponse(c, []string{}, 0, cutoff, "", false)
 			return
 		}
 		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to list log files: %v", err)})
@@ -71,10 +69,20 @@ func (h *Handler) GetLogs(c *gin.Context) {
 	}
 
 	cutoff := parseCutoff(c.Query("after"))
+	if strings.TrimSpace(c.Query("cursor")) == "" && cutoff == 0 && limit > 0 {
+		result, errTail := tailLogFiles(files, limit, 0)
+		if errTail != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to read log files: %v", errTail)})
+			return
+		}
+		writeLogsResponse(c, result.lines, len(result.lines), result.latest, result.nextCursor, false)
+		return
+	}
+
 	acc := newLogAccumulator(cutoff, limit)
 	for i := range files {
 		if errProcess := acc.consumeFile(files[i]); errProcess != nil {
-			c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to read log file %s: %v", files[i], errProcess)})
+			c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to read log file: %v", errProcess)})
 			return
 		}
 	}
@@ -83,11 +91,12 @@ func (h *Handler) GetLogs(c *gin.Context) {
 	if latest == 0 || latest < cutoff {
 		latest = cutoff
 	}
-	c.JSON(http.StatusOK, gin.H{
-		"lines":            lines,
-		"line-count":       total,
-		"latest-timestamp": latest,
-	})
+	nextCursor, errCursor := cursorForLatestLogFile(files, latest)
+	if errCursor != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to prepare log cursor: %v", errCursor)})
+		return
+	}
+	writeLogsResponse(c, lines, total, latest, nextCursor, false)
 }
 
 // DeleteLogs removes all rotated log files and truncates the active log.
@@ -498,6 +507,140 @@ type completeLogRead struct {
 	hitLimit  bool
 }
 
+type logReadResult struct {
+	lines      []string
+	latest     int64
+	nextCursor string
+}
+
+func writeLogsResponse(c *gin.Context, lines []string, lineCount int, latest int64, nextCursor string, cursorReset bool) {
+	if lines == nil {
+		lines = []string{}
+	}
+	payload := gin.H{
+		"lines":            lines,
+		"line-count":       lineCount,
+		"latest-timestamp": latest,
+		"next-cursor":      nextCursor,
+	}
+	if cursorReset {
+		payload["cursor-reset"] = true
+	}
+	c.JSON(http.StatusOK, payload)
+}
+
+func tailLogFiles(files []string, limit int, fallbackLatest int64) (logReadResult, error) {
+	result := logReadResult{
+		lines:  []string{},
+		latest: fallbackLatest,
+	}
+	for i := len(files) - 1; i >= 0; i-- {
+		remaining := 0
+		if limit > 0 {
+			remaining = limit - len(result.lines)
+			if remaining <= 0 {
+				break
+			}
+		}
+		read, errRead := readTailLogLines(files[i], remaining)
+		if errRead != nil {
+			if errors.Is(errRead, os.ErrNotExist) {
+				continue
+			}
+			return logReadResult{}, errRead
+		}
+		if len(read.lines) == 0 {
+			continue
+		}
+		result.lines = append(append([]string{}, read.lines...), result.lines...)
+		if read.latest > result.latest {
+			result.latest = read.latest
+		}
+	}
+	nextCursor, errCursor := cursorForLatestLogFile(files, result.latest)
+	if errCursor != nil {
+		return logReadResult{}, errCursor
+	}
+	result.nextCursor = nextCursor
+	return result, nil
+}
+
+func readTailLogLines(path string, limit int) (completeLogRead, error) {
+	boundary, errBoundary := completeLogBoundary(path)
+	if errBoundary != nil {
+		return completeLogRead{}, errBoundary
+	}
+	if boundary == 0 {
+		return completeLogRead{lines: []string{}}, nil
+	}
+	start, errStart := tailStartOffset(path, boundary, limit)
+	if errStart != nil {
+		return completeLogRead{}, errStart
+	}
+	return readCompleteLogLines(path, start, boundary, limit)
+}
+
+func tailStartOffset(path string, boundary int64, limit int) (int64, error) {
+	if limit <= 0 {
+		return 0, nil
+	}
+	file, errOpen := os.Open(path)
+	if errOpen != nil {
+		return 0, errOpen
+	}
+	defer func() {
+		_ = file.Close()
+	}()
+	buf := make([]byte, 32*1024)
+	pos := boundary
+	lineBreaks := 0
+	for pos > 0 {
+		chunk := minInt64(int64(len(buf)), pos)
+		pos -= chunk
+		n, errRead := file.ReadAt(buf[:chunk], pos)
+		if errRead != nil && errRead != io.EOF {
+			return 0, errRead
+		}
+		if n <= 0 {
+			continue
+		}
+		data := buf[:n]
+		for len(data) > 0 {
+			idx := bytes.LastIndexByte(data, '\n')
+			if idx < 0 {
+				break
+			}
+			lineBreaks++
+			if lineBreaks > limit {
+				return pos + int64(idx) + 1, nil
+			}
+			data = data[:idx]
+		}
+	}
+	return 0, nil
+}
+
+func cursorForLatestLogFile(files []string, latest int64) (string, error) {
+	for i := len(files) - 1; i >= 0; i-- {
+		boundary, errBoundary := completeLogBoundary(files[i])
+		if errBoundary != nil {
+			if errors.Is(errBoundary, os.ErrNotExist) {
+				continue
+			}
+			return "", errBoundary
+		}
+		cursor, errCursor := newLogCursor(files[i], boundary, latest)
+		if errCursor != nil {
+			if errors.Is(errCursor, os.ErrNotExist) {
+				continue
+			}
+			return "", errCursor
+		}
+		return cursor, nil
+	}
+	return "", nil
+}
+
 func encodeLogCursor(cursor logCursor) (string, error) {
 	raw, err := json.Marshal(cursor)
 	if err != nil {
@@ -760,7 +903,7 @@ func completeLogBoundary(path string) (int64, error) {
 		if n <= 0 {
 			continue
 		}
-		if idx := strings.LastIndexByte(string(buf[:n]), '\n'); idx >= 0 {
+		if idx := bytes.LastIndexByte(buf[:n], '\n'); idx >= 0 {
 			return pos + int64(idx) + 1, nil
 		}
 	}
diff --git a/internal/api/handlers/management/logs_test.go b/internal/api/handlers/management/logs_test.go
index 4f15f706..acc021a1 100644
--- a/internal/api/handlers/management/logs_test.go
+++ b/internal/api/handlers/management/logs_test.go
@@ -3,11 +3,18 @@ package management
 import (
 	"encoding/base64"
 	"encoding/json"
+	"net/http"
+	"net/http/httptest"
 	"os"
 	"path/filepath"
 	"reflect"
+	"strconv"
 	"strings"
 	"testing"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/router-for-me/CLIProxyAPI/v7/internal/config"
 )
 
 func TestDecodeLogCursorRejectsUnsafeFiles(t *testing.T) {
@@ -126,6 +133,80 @@ func TestReadCompleteLogLinesSkipsTrailingPartial(t *testing.T) {
 	}
 }
 
+func TestGetLogsTailLimitReturnsRecentLinesWithCursor(t *testing.T) {
+	dir := t.TempDir()
+	lines := []string{
+		"[2026-06-15 10:00:00] first",
+		"[2026-06-15 10:00:01] second",
+		"[2026-06-15 10:00:02] third",
+		"[2026-06-15 10:00:03] fourth",
+	}
+	writeMainLog(t, dir, strings.Join(lines, "\n")+"\n")
+
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=2")
+	wantLines := []string{lines[2], lines[3]}
+	if !reflect.DeepEqual(resp.Lines, wantLines) {
+		t.Fatalf("lines = %#v, want %#v", resp.Lines, wantLines)
+	}
+	if resp.LineCount != 2 {
+		t.Fatalf("line-count = %d, want 2", resp.LineCount)
+	}
+	if resp.NextCursor == "" {
+		t.Fatal("next-cursor is empty")
+	}
+	wantLatest := time.Date(2026, 6, 15, 10, 0, 3, 0, time.Local).Unix()
+	if resp.LatestTimestamp != wantLatest {
+		t.Fatalf("latest-timestamp = %d, want %d", resp.LatestTimestamp, wantLatest)
+	}
+}
+
+func TestGetLogsNoLimitKeepsFullScanBehavior(t *testing.T) {
+	dir := t.TempDir()
+	writeMainLog(t, dir, "complete\npartial")
+
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs")
+	wantLines := []string{"complete", "partial"}
+	if !reflect.DeepEqual(resp.Lines, wantLines) {
+		t.Fatalf("lines = %#v, want %#v", resp.Lines, wantLines)
+	}
+	if resp.LineCount != 2 {
+		t.Fatalf("line-count = %d, want full scan count 2", resp.LineCount)
+	}
+	if resp.NextCursor == "" {
+		t.Fatal("next-cursor is empty")
+	}
+	cursor, errCursor := decodeLogCursor(resp.NextCursor)
+	if errCursor != nil {
+		t.Fatalf("decode next-cursor: %v", errCursor)
+	}
+	if cursor.Offset != int64(len("complete\n")) {
+		t.Fatalf("cursor offset = %d, want complete-line boundary", cursor.Offset)
+	}
+}
+
+func TestGetLogsAfterKeepsTimestampScanAndReturnsCursor(t *testing.T) {
+	dir := t.TempDir()
+	lines := []string{
+		"[2026-06-15 10:00:00] first",
+		"[2026-06-15 10:00:01] second",
+		"[2026-06-15 10:00:02] third",
+	}
+	writeMainLog(t, dir, strings.Join(lines, "\n")+"\n")
+
+	cutoff := time.Date(2026, 6, 15, 10, 0, 0, 0, time.Local).Unix()
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?after="+strconv.FormatInt(cutoff, 10))
+	wantLines := []string{lines[1], lines[2]}
+	if !reflect.DeepEqual(resp.Lines, wantLines) {
+		t.Fatalf("lines = %#v, want %#v", resp.Lines, wantLines)
+	}
+	if resp.LineCount != 3 {
+		t.Fatalf("line-count = %d, want full scan count 3", resp.LineCount)
+	}
+	if resp.NextCursor == "" {
+		t.Fatal("next-cursor is empty")
+	}
+}
+
 func mustEncodeRawCursor(t *testing.T, cursor logCursor) string {
 	t.Helper()
 	raw, err := json.Marshal(cursor)
@@ -134,3 +215,44 @@ func mustEncodeRawCursor(t *testing.T, cursor logCursor) string {
 	}
 	return base64.RawURLEncoding.EncodeToString(raw)
 }
+
+type logsAPIResponse struct {
+	Lines           []string `json:"lines"`
+	LineCount       int      `json:"line-count"`
+	LatestTimestamp int64    `json:"latest-timestamp"`
+	NextCursor      string   `json:"next-cursor"`
+	CursorReset     bool     `json:"cursor-reset"`
+}
+
+func newLogsTestHandler(dir string, loggingToFile bool) *Handler {
+	h := NewHandlerWithoutConfigFilePath(&config.Config{LoggingToFile: loggingToFile}, nil)
+	h.SetLogDirectory(dir)
+	return h
+}
+
+func performGetLogs(t *testing.T, h *Handler, target string) logsAPIResponse {
+	t.Helper()
+	gin.SetMode(gin.TestMode)
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodGet, target, nil)
+	h.GetLogs(c)
+	if rec.Code != http.StatusOK {
+		t.Fatalf("GetLogs status = %d, body = %s", rec.Code, rec.Body.String())
+	}
+	var resp logsAPIResponse
+	if err := json.Unmarshal(rec.Body.Bytes(), &resp); err != nil {
+		t.Fatalf("decode response: %v", err)
+	}
+	if resp.Lines == nil {
+		resp.Lines = []string{}
+	}
+	return resp
+}
+
+func writeMainLog(t *testing.T, dir, content string) {
+	t.Helper()
+	if err := os.WriteFile(filepath.Join(dir, defaultLogFileName), []byte(content), 0o644); err != nil {
+		t.Fatalf("write main log: %v", err)
+	}
+}
-- 
2.51.2


From 331daa24ad9061b20b28d87e21e61c2089f7f707 Mon Sep 17 00:00:00 2001
From: LTbinglingfeng <tan13318527080@163.com>
Date: Mon, 15 Jun 2026 02:10:25 +0800
Subject: [PATCH 03/10] Read management logs from cursors

---
 internal/api/handlers/management/logs.go      | 164 +++++++++++-
 internal/api/handlers/management/logs_test.go | 242 +++++++++++++++++-
 2 files changed, 396 insertions(+), 10 deletions(-)

diff --git a/internal/api/handlers/management/logs.go b/internal/api/handlers/management/logs.go
index fa3b6cb0..c41a0ed1 100644
--- a/internal/api/handlers/management/logs.go
+++ b/internal/api/handlers/management/logs.go
@@ -51,11 +51,18 @@ func (h *Handler) GetLogs(c *gin.Context) {
 		return
 	}
 
+	rawCursor := strings.TrimSpace(c.Query("cursor"))
 	files, err := h.collectLogFiles(logDir)
 	if err != nil {
 		if os.IsNotExist(err) {
 			cutoff := parseCutoff(c.Query("after"))
-			writeLogsResponse(c, []string{}, 0, cutoff, "", false)
+			latest := cutoff
+			if rawCursor != "" {
+				if cursor, errCursor := decodeLogCursor(rawCursor); errCursor == nil && cursor.LatestTimestamp > latest {
+					latest = cursor.LatestTimestamp
+				}
+			}
+			writeLogsResponse(c, []string{}, 0, latest, "", rawCursor != "")
 			return
 		}
 		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to list log files: %v", err)})
@@ -69,7 +76,26 @@ func (h *Handler) GetLogs(c *gin.Context) {
 	}
 
 	cutoff := parseCutoff(c.Query("after"))
-	if strings.TrimSpace(c.Query("cursor")) == "" && cutoff == 0 && limit > 0 {
+	if rawCursor != "" {
+		result, reset, errCursor := readLogFilesFromCursor(logDir, files, rawCursor, limit)
+		if errCursor != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to read log files: %v", errCursor)})
+			return
+		}
+		if reset {
+			result, errCursor = tailLogFiles(files, limit, result.latest)
+			if errCursor != nil {
+				c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to read log files: %v", errCursor)})
+				return
+			}
+			writeLogsResponse(c, result.lines, len(result.lines), result.latest, result.nextCursor, true)
+			return
+		}
+		writeLogsResponse(c, result.lines, len(result.lines), result.latest, result.nextCursor, false)
+		return
+	}
+
+	if cutoff == 0 && limit > 0 {
 		result, errTail := tailLogFiles(files, limit, 0)
 		if errTail != nil {
 			c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to read log files: %v", errTail)})
@@ -641,6 +667,140 @@ func cursorForLatestLogFile(files []string, latest int64) (string, error) {
 	return "", nil
 }
 
+func readLogFilesFromCursor(logDir string, files []string, raw string, limit int) (logReadResult, bool, error) {
+	cursor, errDecode := decodeLogCursor(raw)
+	if errDecode != nil {
+		return logReadResult{lines: []string{}}, true, nil
+	}
+	result := logReadResult{
+		lines:      []string{},
+		latest:     cursor.LatestTimestamp,
+		nextCursor: raw,
+	}
+	if _, errPath := safeLogFilePath(logDir, cursor.File); errPath != nil {
+		return result, true, nil
+	}
+	startIndex, found, errLocate := locateLogCursorFile(files, cursor)
+	if errLocate != nil {
+		return result, false, errLocate
+	}
+	if !found {
+		return result, true, nil
+	}
+
+	currentCursorPath := files[startIndex]
+	currentCursorOffset := cursor.Offset
+	advanced := false
+	for i := startIndex; i < len(files); i++ {
+		remaining := 0
+		if limit > 0 {
+			remaining = limit - len(result.lines)
+			if remaining <= 0 {
+				break
+			}
+		}
+		offset := int64(0)
+		if i == startIndex {
+			offset = cursor.Offset
+		}
+		read, errRead := readCompleteLogLines(files[i], offset, -1, remaining)
+		if errRead != nil {
+			if errors.Is(errRead, os.ErrNotExist) {
+				return result, true, nil
+			}
+			return result, false, errRead
+		}
+		if len(read.lines) > 0 {
+			result.lines = append(result.lines, read.lines...)
+			if read.latest > result.latest {
+				result.latest = read.latest
+			}
+			currentCursorPath = files[i]
+			currentCursorOffset = read.endOffset
+			advanced = true
+		}
+		if read.hitLimit {
+			break
+		}
+	}
+	if !advanced {
+		return result, false, nil
+	}
+
+	nextCursor, errCursor := newLogCursor(currentCursorPath, currentCursorOffset, result.latest)
+	if errCursor != nil {
+		if errors.Is(errCursor, os.ErrNotExist) {
+			return result, true, nil
+		}
+		return result, false, errCursor
+	}
+	result.nextCursor = nextCursor
+	return result, false, nil
+}
+
+func locateLogCursorFile(files []string, cursor logCursor) (int, bool, error) {
+	nameToIndex := make(map[string]int, len(files))
+	for i := range files {
+		nameToIndex[filepath.Base(files[i])] = i
+	}
+	if index, ok := nameToIndex[cursor.File]; ok {
+		matches, truncated, errMatch := logFileMatchesCursor(files[index], cursor)
+		if errMatch != nil {
+			if errors.Is(errMatch, os.ErrNotExist) {
+				return 0, false, nil
+			}
+			return 0, false, errMatch
+		}
+		if truncated {
+			return 0, false, nil
+		}
+		if matches {
+			return index, true, nil
+		}
+	}
+
+	if cursor.File != defaultLogFileName || cursor.Offset == 0 {
+		return 0, false, nil
+	}
+	for i := range files {
+		if filepath.Base(files[i]) == defaultLogFileName {
+			continue
+		}
+		matches, truncated, errMatch := logFileMatchesCursor(files[i], cursor)
+		if errMatch != nil {
+			if errors.Is(errMatch, os.ErrNotExist) {
+				continue
+			}
+			return 0, false, errMatch
+		}
+		if truncated {
+			continue
+		}
+		if matches {
+			return i, true, nil
+		}
+	}
+	return 0, false, nil
+}
+
+func logFileMatchesCursor(path string, cursor logCursor) (bool, bool, error) {
+	info, errStat := os.Stat(path)
+	if errStat != nil {
+		return false, false, errStat
+	}
+	if info.IsDir() {
+		return false, false, fmt.Errorf("invalid log file")
+	}
+	if info.Size() < cursor.Offset {
+		return false, true, nil
+	}
+	fingerprint, errFingerprint := logFileFingerprint(path, cursor.Offset)
+	if errFingerprint != nil {
+		return false, false, errFingerprint
+	}
+	return fingerprint == cursor.Fingerprint, false, nil
+}
+
 func encodeLogCursor(cursor logCursor) (string, error) {
 	raw, err := json.Marshal(cursor)
 	if err != nil {
diff --git a/internal/api/handlers/management/logs_test.go b/internal/api/handlers/management/logs_test.go
index acc021a1..b7b73b4d 100644
--- a/internal/api/handlers/management/logs_test.go
+++ b/internal/api/handlers/management/logs_test.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"net/http"
 	"net/http/httptest"
+	"net/url"
 	"os"
 	"path/filepath"
 	"reflect"
@@ -207,6 +208,210 @@ func TestGetLogsAfterKeepsTimestampScanAndReturnsCursor(t *testing.T) {
 	}
 }
 
+func TestGetLogsCursorReturnsOnlyNewCompleteLines(t *testing.T) {
+	dir := t.TempDir()
+	lines := []string{
+		"[2026-06-15 10:00:00] first",
+		"[2026-06-15 10:00:01] second",
+		"[2026-06-15 10:00:02] third",
+	}
+	writeMainLog(t, dir, strings.Join(lines, "\n")+"\n")
+	initial := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=2")
+	if initial.NextCursor == "" {
+		t.Fatal("initial next-cursor is empty")
+	}
+
+	appendMainLog(t, dir, "[2026-06-15 10:00:03] fourth\n")
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(initial.NextCursor)+"&limit=10")
+	wantLines := []string{"[2026-06-15 10:00:03] fourth"}
+	if !reflect.DeepEqual(resp.Lines, wantLines) {
+		t.Fatalf("lines = %#v, want %#v", resp.Lines, wantLines)
+	}
+	if resp.LineCount != 1 {
+		t.Fatalf("line-count = %d, want 1", resp.LineCount)
+	}
+	if resp.CursorReset {
+		t.Fatal("cursor-reset = true, want false")
+	}
+	wantLatest := time.Date(2026, 6, 15, 10, 0, 3, 0, time.Local).Unix()
+	if resp.LatestTimestamp != wantLatest {
+		t.Fatalf("latest-timestamp = %d, want %d", resp.LatestTimestamp, wantLatest)
+	}
+}
+
+func TestGetLogsCursorNoNewLinesKeepsCursorStable(t *testing.T) {
+	dir := t.TempDir()
+	line := "[2026-06-15 10:00:00] first"
+	writeMainLog(t, dir, line+"\n")
+	initial := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=1")
+
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(initial.NextCursor)+"&limit=10")
+	if len(resp.Lines) != 0 {
+		t.Fatalf("lines = %#v, want empty", resp.Lines)
+	}
+	if resp.LineCount != 0 {
+		t.Fatalf("line-count = %d, want 0", resp.LineCount)
+	}
+	if resp.NextCursor != initial.NextCursor {
+		t.Fatalf("next-cursor changed with no complete lines")
+	}
+	if resp.LatestTimestamp != initial.LatestTimestamp {
+		t.Fatalf("latest-timestamp = %d, want %d", resp.LatestTimestamp, initial.LatestTimestamp)
+	}
+}
+
+func TestGetLogsCursorDoesNotAdvancePastTrailingPartial(t *testing.T) {
+	dir := t.TempDir()
+	line := "[2026-06-15 10:00:00] first"
+	writeMainLog(t, dir, line+"\n")
+	initial := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=1")
+
+	appendMainLog(t, dir, "partial")
+	partial := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(initial.NextCursor)+"&limit=10")
+	if len(partial.Lines) != 0 {
+		t.Fatalf("partial lines = %#v, want empty", partial.Lines)
+	}
+	if partial.NextCursor != initial.NextCursor {
+		t.Fatalf("cursor advanced past partial line")
+	}
+
+	appendMainLog(t, dir, "\n")
+	complete := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(initial.NextCursor)+"&limit=10")
+	if !reflect.DeepEqual(complete.Lines, []string{"partial"}) {
+		t.Fatalf("complete lines = %#v, want partial", complete.Lines)
+	}
+	if complete.LatestTimestamp != initial.LatestTimestamp {
+		t.Fatalf("latest-timestamp = %d, want %d", complete.LatestTimestamp, initial.LatestTimestamp)
+	}
+}
+
+func TestGetLogsCursorResetAfterTruncateTailsLimit(t *testing.T) {
+	dir := t.TempDir()
+	lines := []string{
+		"[2026-06-15 10:00:00] first",
+		"[2026-06-15 10:00:01] second",
+		"[2026-06-15 10:00:02] third",
+	}
+	writeMainLog(t, dir, strings.Join(lines, "\n")+"\n")
+	initial := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=3")
+
+	resetLine := "[2026-06-15 10:00:03] reset"
+	writeMainLog(t, dir, resetLine+"\n")
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(initial.NextCursor)+"&limit=1")
+	if !resp.CursorReset {
+		t.Fatal("cursor-reset = false, want true")
+	}
+	if !reflect.DeepEqual(resp.Lines, []string{resetLine}) {
+		t.Fatalf("lines = %#v, want reset tail", resp.Lines)
+	}
+	if resp.LineCount != 1 {
+		t.Fatalf("line-count = %d, want 1", resp.LineCount)
+	}
+}
+
+func TestGetLogsCursorReadsAcrossRotation(t *testing.T) {
+	dir := t.TempDir()
+	line1 := "[2026-06-15 10:00:00] first"
+	line2 := "[2026-06-15 10:00:01] second"
+	line3 := "[2026-06-15 10:00:02] third"
+	writeMainLog(t, dir, line1+"\n")
+	initial := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=1")
+
+	appendMainLog(t, dir, line2+"\n")
+	if err := os.Rename(filepath.Join(dir, defaultLogFileName), filepath.Join(dir, defaultLogFileName+".1")); err != nil {
+		t.Fatalf("rotate main log: %v", err)
+	}
+	writeMainLog(t, dir, line3+"\n")
+
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(initial.NextCursor)+"&limit=10")
+	wantLines := []string{line2, line3}
+	if !reflect.DeepEqual(resp.Lines, wantLines) {
+		t.Fatalf("lines = %#v, want %#v", resp.Lines, wantLines)
+	}
+	if resp.CursorReset {
+		t.Fatal("cursor-reset = true, want false")
+	}
+}
+
+func TestGetLogsInvalidCursorResetsToTail(t *testing.T) {
+	dir := t.TempDir()
+	lines := []string{
+		"[2026-06-15 10:00:00] first",
+		"[2026-06-15 10:00:01] second",
+	}
+	writeMainLog(t, dir, strings.Join(lines, "\n")+"\n")
+
+	cases := []string{
+		"not-base64",
+		mustEncodeRawCursor(t, logCursor{
+			Version:     logCursorVersion,
+			File:        "../secret",
+			Fingerprint: "fingerprint",
+		}),
+	}
+	for _, raw := range cases {
+		resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(raw)+"&limit=1")
+		if !resp.CursorReset {
+			t.Fatalf("cursor-reset = false for cursor %q", raw)
+		}
+		if !reflect.DeepEqual(resp.Lines, []string{lines[1]}) {
+			t.Fatalf("lines = %#v, want latest line", resp.Lines)
+		}
+		if resp.LineCount != 1 {
+			t.Fatalf("line-count = %d, want 1", resp.LineCount)
+		}
+	}
+}
+
+func TestGetLogsMissingRotatedCursorFileResetsToTail(t *testing.T) {
+	dir := t.TempDir()
+	current := "[2026-06-15 10:00:01] current"
+	writeMainLog(t, dir, current+"\n")
+	rotatedPath := filepath.Join(dir, defaultLogFileName+".1")
+	if err := os.WriteFile(rotatedPath, []byte("[2026-06-15 10:00:00] old\n"), 0o644); err != nil {
+		t.Fatalf("write rotated log: %v", err)
+	}
+	cursor, errCursor := newLogCursor(rotatedPath, int64(len("[2026-06-15 10:00:00] old\n")), 0)
+	if errCursor != nil {
+		t.Fatalf("newLogCursor() error = %v", errCursor)
+	}
+	if errRemove := os.Remove(rotatedPath); errRemove != nil {
+		t.Fatalf("remove rotated log: %v", errRemove)
+	}
+
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(cursor)+"&limit=1")
+	if !resp.CursorReset {
+		t.Fatal("cursor-reset = false, want true")
+	}
+	if !reflect.DeepEqual(resp.Lines, []string{current}) {
+		t.Fatalf("lines = %#v, want current tail", resp.Lines)
+	}
+}
+
+func TestGetLogsMissingLogDirKeepsOKEmptyResponse(t *testing.T) {
+	dir := filepath.Join(t.TempDir(), "missing")
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape("not-base64")+"&limit=1")
+	if len(resp.Lines) != 0 {
+		t.Fatalf("lines = %#v, want empty", resp.Lines)
+	}
+	if resp.LineCount != 0 {
+		t.Fatalf("line-count = %d, want 0", resp.LineCount)
+	}
+	if !resp.CursorReset {
+		t.Fatal("cursor-reset = false, want true for cursor against missing log dir")
+	}
+}
+
+func TestGetLogsLoggingDisabledKeepsBadRequest(t *testing.T) {
+	status, body := performGetLogsRaw(t, newLogsTestHandler(t.TempDir(), false), "/v0/management/logs?cursor=not-base64&limit=1")
+	if status != http.StatusBadRequest {
+		t.Fatalf("status = %d, want %d", status, http.StatusBadRequest)
+	}
+	if !strings.Contains(body, "logging to file disabled") {
+		t.Fatalf("body = %s, want logging disabled error", body)
+	}
+}
+
 func mustEncodeRawCursor(t *testing.T, cursor logCursor) string {
 	t.Helper()
 	raw, err := json.Marshal(cursor)
@@ -232,16 +437,12 @@ func newLogsTestHandler(dir string, loggingToFile bool) *Handler {
 
 func performGetLogs(t *testing.T, h *Handler, target string) logsAPIResponse {
 	t.Helper()
-	gin.SetMode(gin.TestMode)
-	rec := httptest.NewRecorder()
-	c, _ := gin.CreateTestContext(rec)
-	c.Request = httptest.NewRequest(http.MethodGet, target, nil)
-	h.GetLogs(c)
-	if rec.Code != http.StatusOK {
-		t.Fatalf("GetLogs status = %d, body = %s", rec.Code, rec.Body.String())
+	status, body := performGetLogsRaw(t, h, target)
+	if status != http.StatusOK {
+		t.Fatalf("GetLogs status = %d, body = %s", status, body)
 	}
 	var resp logsAPIResponse
-	if err := json.Unmarshal(rec.Body.Bytes(), &resp); err != nil {
+	if err := json.Unmarshal([]byte(body), &resp); err != nil {
 		t.Fatalf("decode response: %v", err)
 	}
 	if resp.Lines == nil {
@@ -250,9 +451,34 @@ func performGetLogs(t *testing.T, h *Handler, target string) logsAPIResponse {
 	return resp
 }
 
+func performGetLogsRaw(t *testing.T, h *Handler, target string) (int, string) {
+	t.Helper()
+	gin.SetMode(gin.TestMode)
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodGet, target, nil)
+	h.GetLogs(c)
+	return rec.Code, rec.Body.String()
+}
+
 func writeMainLog(t *testing.T, dir, content string) {
 	t.Helper()
 	if err := os.WriteFile(filepath.Join(dir, defaultLogFileName), []byte(content), 0o644); err != nil {
 		t.Fatalf("write main log: %v", err)
 	}
 }
+
+func appendMainLog(t *testing.T, dir, content string) {
+	t.Helper()
+	file, errOpen := os.OpenFile(filepath.Join(dir, defaultLogFileName), os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
+	if errOpen != nil {
+		t.Fatalf("open main log: %v", errOpen)
+	}
+	if _, errWrite := file.WriteString(content); errWrite != nil {
+		_ = file.Close()
+		t.Fatalf("append main log: %v", errWrite)
+	}
+	if errClose := file.Close(); errClose != nil {
+		t.Fatalf("close main log: %v", errClose)
+	}
+}
-- 
2.51.2


From 0d82daca6bf2348872cc0c309060dcb2e0db3895 Mon Sep 17 00:00:00 2001
From: LTbinglingfeng <tan13318527080@163.com>
Date: Mon, 15 Jun 2026 02:17:57 +0800
Subject: [PATCH 04/10] Preserve management log line counts

---
 internal/api/handlers/management/logs.go      | 67 ++++++++++++++++++-
 internal/api/handlers/management/logs_test.go |  4 +-
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/internal/api/handlers/management/logs.go b/internal/api/handlers/management/logs.go
index c41a0ed1..f42433e2 100644
--- a/internal/api/handlers/management/logs.go
+++ b/internal/api/handlers/management/logs.go
@@ -101,7 +101,12 @@ func (h *Handler) GetLogs(c *gin.Context) {
 			c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to read log files: %v", errTail)})
 			return
 		}
-		writeLogsResponse(c, result.lines, len(result.lines), result.latest, result.nextCursor, false)
+		total, errCount := countLogFileLines(files)
+		if errCount != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to read log files: %v", errCount)})
+			return
+		}
+		writeLogsResponse(c, result.lines, total, result.latest, result.nextCursor, false)
 		return
 	}
 
@@ -606,6 +611,66 @@ func readTailLogLines(path string, limit int) (completeLogRead, error) {
 	return readCompleteLogLines(path, start, boundary, limit)
 }
 
+func countLogFileLines(files []string) (int, error) {
+	total := 0
+	for i := range files {
+		count, errCount := countLogLines(files[i])
+		if errCount != nil {
+			if errors.Is(errCount, os.ErrNotExist) {
+				continue
+			}
+			return 0, errCount
+		}
+		total += count
+	}
+	return total, nil
+}
+
+func countLogLines(path string) (int, error) {
+	file, errOpen := os.Open(path)
+	if errOpen != nil {
+		return 0, errOpen
+	}
+	defer func() {
+		_ = file.Close()
+	}()
+	info, errStat := file.Stat()
+	if errStat != nil {
+		return 0, errStat
+	}
+	if info.IsDir() {
+		return 0, fmt.Errorf("invalid log file")
+	}
+
+	buf := make([]byte, 32*1024)
+	count := 0
+	lineLen := 0
+	for {
+		n, errRead := file.Read(buf)
+		for _, b := range buf[:n] {
+			if b == '\n' {
+				count++
+				lineLen = 0
+				continue
+			}
+			lineLen++
+			if lineLen > logScannerMaxBuffer {
+				return 0, fmt.Errorf("log line exceeds %d bytes", logScannerMaxBuffer)
+			}
+		}
+		if errRead == io.EOF {
+			break
+		}
+		if errRead != nil {
+			return 0, errRead
+		}
+	}
+	if lineLen > 0 {
+		count++
+	}
+	return count, nil
+}
+
 func tailStartOffset(path string, boundary int64, limit int) (int64, error) {
 	if limit <= 0 {
 		return 0, nil
diff --git a/internal/api/handlers/management/logs_test.go b/internal/api/handlers/management/logs_test.go
index b7b73b4d..55b5ba3f 100644
--- a/internal/api/handlers/management/logs_test.go
+++ b/internal/api/handlers/management/logs_test.go
@@ -149,8 +149,8 @@ func TestGetLogsTailLimitReturnsRecentLinesWithCursor(t *testing.T) {
 	if !reflect.DeepEqual(resp.Lines, wantLines) {
 		t.Fatalf("lines = %#v, want %#v", resp.Lines, wantLines)
 	}
-	if resp.LineCount != 2 {
-		t.Fatalf("line-count = %d, want 2", resp.LineCount)
+	if resp.LineCount != 4 {
+		t.Fatalf("line-count = %d, want full scan count 4", resp.LineCount)
 	}
 	if resp.NextCursor == "" {
 		t.Fatal("next-cursor is empty")
-- 
2.51.2


From d417fa534fa77ed34899133a9bbe1d5503dd812a Mon Sep 17 00:00:00 2001
From: LTbinglingfeng <tan13318527080@163.com>
Date: Mon, 15 Jun 2026 02:18:58 +0800
Subject: [PATCH 05/10] Bound management log cursor reads

---
 internal/api/handlers/management/logs.go      | 52 +++++++++++++------
 internal/api/handlers/management/logs_test.go | 18 +++++++
 2 files changed, 53 insertions(+), 17 deletions(-)

diff --git a/internal/api/handlers/management/logs.go b/internal/api/handlers/management/logs.go
index f42433e2..75cdcde6 100644
--- a/internal/api/handlers/management/logs.go
+++ b/internal/api/handlers/management/logs.go
@@ -1062,29 +1062,47 @@ func readCompleteLogLines(path string, offset, maxOffset int64, limit int) (comp
 		return completeLogRead{}, fmt.Errorf("invalid log offset")
 	}
 
-	reader := bufio.NewReader(io.NewSectionReader(file, offset, maxOffset-offset))
+	reader := io.NewSectionReader(file, offset, maxOffset-offset)
 	result := completeLogRead{
 		lines:     []string{},
 		endOffset: offset,
 	}
 	currentOffset := offset
+	buf := make([]byte, 32*1024)
+	line := make([]byte, 0, logScannerInitialBuffer)
 	for {
-		raw, errRead := reader.ReadString('\n')
-		if strings.HasSuffix(raw, "\n") {
-			currentOffset += int64(len(raw))
-			line := strings.TrimSuffix(raw, "\n")
-			line = strings.TrimRight(line, "\r")
-			result.lines = append(result.lines, line)
-			result.endOffset = currentOffset
-			if ts := parseTimestamp(line); ts > result.latest {
-				result.latest = ts
-			}
-			if limit > 0 && len(result.lines) >= limit {
-				result.hitLimit = true
-				break
-			}
-			if errRead == nil {
-				continue
+		n, errRead := reader.Read(buf)
+		if n > 0 {
+			data := buf[:n]
+			for len(data) > 0 {
+				idx := bytes.IndexByte(data, '\n')
+				if idx < 0 {
+					if len(line)+len(data) > logScannerMaxBuffer {
+						return completeLogRead{}, fmt.Errorf("log line exceeds %d bytes", logScannerMaxBuffer)
+					}
+					line = append(line, data...)
+					currentOffset += int64(len(data))
+					break
+				}
+
+				segment := data[:idx]
+				if len(line)+len(segment) > logScannerMaxBuffer {
+					return completeLogRead{}, fmt.Errorf("log line exceeds %d bytes", logScannerMaxBuffer)
+				}
+				line = append(line, segment...)
+				currentOffset += int64(idx) + 1
+				text := strings.TrimRight(string(line), "\r")
+				result.lines = append(result.lines, text)
+				result.endOffset = currentOffset
+				if ts := parseTimestamp(text); ts > result.latest {
+					result.latest = ts
+				}
+				line = line[:0]
+				if limit > 0 && len(result.lines) >= limit {
+					result.hitLimit = true
+					return result, nil
+				}
+				data = data[idx+1:]
 			}
 		}
 		if errRead == io.EOF {
diff --git a/internal/api/handlers/management/logs_test.go b/internal/api/handlers/management/logs_test.go
index 55b5ba3f..c0275e6a 100644
--- a/internal/api/handlers/management/logs_test.go
+++ b/internal/api/handlers/management/logs_test.go
@@ -239,6 +239,24 @@ func TestGetLogsCursorReturnsOnlyNewCompleteLines(t *testing.T) {
 	}
 }
 
+func TestGetLogsCursorRejectsOversizedLine(t *testing.T) {
+	dir := t.TempDir()
+	writeMainLog(t, dir, "[2026-06-15 10:00:00] first\n")
+	initial := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=1")
+	if initial.NextCursor == "" {
+		t.Fatal("initial next-cursor is empty")
+	}
+
+	appendMainLog(t, dir, strings.Repeat("x", logScannerMaxBuffer+1)+"\n")
+	status, body := performGetLogsRaw(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(initial.NextCursor)+"&limit=1")
+	if status != http.StatusInternalServerError {
+		t.Fatalf("status = %d, want %d", status, http.StatusInternalServerError)
+	}
+	if !strings.Contains(body, "log line exceeds") {
+		t.Fatalf("body = %s, want oversized line error", body)
+	}
+}
+
 func TestGetLogsCursorNoNewLinesKeepsCursorStable(t *testing.T) {
 	dir := t.TempDir()
 	line := "[2026-06-15 10:00:00] first"
-- 
2.51.2


From 917cec3bf622121af6e2a8252f6db61217914fbf Mon Sep 17 00:00:00 2001
From: LTbinglingfeng <tan13318527080@163.com>
Date: Mon, 15 Jun 2026 15:46:58 +0800
Subject: [PATCH 06/10] Continue log cursors across rotation

---
 internal/api/handlers/management/logs.go      |  5 +--
 internal/api/handlers/management/logs_test.go | 31 +++++++++++++++++++
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/internal/api/handlers/management/logs.go b/internal/api/handlers/management/logs.go
index 75cdcde6..72e95c6f 100644
--- a/internal/api/handlers/management/logs.go
+++ b/internal/api/handlers/management/logs.go
@@ -816,10 +816,7 @@ func locateLogCursorFile(files []string, cursor logCursor) (int, bool, error) {
 			}
 			return 0, false, errMatch
 		}
-		if truncated {
-			return 0, false, nil
-		}
-		if matches {
+		if matches && !truncated {
 			return index, true, nil
 		}
 	}
diff --git a/internal/api/handlers/management/logs_test.go b/internal/api/handlers/management/logs_test.go
index c0275e6a..1f1056e5 100644
--- a/internal/api/handlers/management/logs_test.go
+++ b/internal/api/handlers/management/logs_test.go
@@ -351,6 +351,37 @@ func TestGetLogsCursorReadsAcrossRotation(t *testing.T) {
 	}
 }
 
+func TestGetLogsCursorReadsRotatedFileWhenNewMainIsSmaller(t *testing.T) {
+	dir := t.TempDir()
+	line1 := "[2026-06-15 10:00:00] first line with enough bytes"
+	line2 := "[2026-06-15 10:00:01] second"
+	line3 := "new"
+	writeMainLog(t, dir, line1+"\n")
+	initial := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=1")
+
+	appendMainLog(t, dir, line2+"\n")
+	if err := os.Rename(filepath.Join(dir, defaultLogFileName), filepath.Join(dir, defaultLogFileName+".1")); err != nil {
+		t.Fatalf("rotate main log: %v", err)
+	}
+	writeMainLog(t, dir, line3+"\n")
+
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(initial.NextCursor)+"&limit=1")
+	if !reflect.DeepEqual(resp.Lines, []string{line2}) {
+		t.Fatalf("lines = %#v, want rotated unread line", resp.Lines)
+	}
+	if resp.CursorReset {
+		t.Fatal("cursor-reset = true, want false")
+	}
+
+	next := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(resp.NextCursor)+"&limit=1")
+	if !reflect.DeepEqual(next.Lines, []string{line3}) {
+		t.Fatalf("next lines = %#v, want new main line", next.Lines)
+	}
+	if next.CursorReset {
+		t.Fatal("next cursor-reset = true, want false")
+	}
+}
+
 func TestGetLogsInvalidCursorResetsToTail(t *testing.T) {
 	dir := t.TempDir()
 	lines := []string{
-- 
2.51.2


From db3fdea4a13b8f2e68ae392833905835f54b645b Mon Sep 17 00:00:00 2001
From: LTbinglingfeng <tan13318527080@163.com>
Date: Mon, 15 Jun 2026 15:50:03 +0800
Subject: [PATCH 07/10] Disambiguate zero-offset log cursors

---
 internal/api/handlers/management/logs.go      | 65 ++++++++++++++--
 internal/api/handlers/management/logs_test.go | 74 +++++++++++++++++++
 2 files changed, 134 insertions(+), 5 deletions(-)

diff --git a/internal/api/handlers/management/logs.go b/internal/api/handlers/management/logs.go
index 72e95c6f..3dfc635a 100644
--- a/internal/api/handlers/management/logs.go
+++ b/internal/api/handlers/management/logs.go
@@ -527,6 +527,7 @@ type logCursor struct {
 	Offset          int64  `json:"offset"`
 	Size            int64  `json:"size"`
 	ModTime         int64  `json:"modTime"`
+	ModTimeUnixNano int64  `json:"modTimeUnixNano,omitempty"`
 	LatestTimestamp int64  `json:"latestTimestamp"`
 	Fingerprint     string `json:"fingerprint"`
 }
@@ -808,6 +809,7 @@ func locateLogCursorFile(files []string, cursor logCursor) (int, bool, error) {
 	for i := range files {
 		nameToIndex[filepath.Base(files[i])] = i
 	}
+	deferEmptyMainMatch := false
 	if index, ok := nameToIndex[cursor.File]; ok {
 		matches, truncated, errMatch := logFileMatchesCursor(files[index], cursor)
 		if errMatch != nil {
@@ -817,17 +819,24 @@ func locateLogCursorFile(files []string, cursor logCursor) (int, bool, error) {
 			return 0, false, errMatch
 		}
 		if matches && !truncated {
-			return index, true, nil
+			if shouldDeferEmptyMainCursorToRotated(files, cursor) {
+				deferEmptyMainMatch = true
+			} else {
+				return index, true, nil
+			}
 		}
 	}
 
-	if cursor.File != defaultLogFileName || cursor.Offset == 0 {
+	if cursor.File != defaultLogFileName || (cursor.Offset == 0 && cursor.Size == 0 && !deferEmptyMainMatch) {
 		return 0, false, nil
 	}
-	for i := range files {
+	for i := len(files) - 1; i >= 0; i-- {
 		if filepath.Base(files[i]) == defaultLogFileName {
 			continue
 		}
+		if cursor.Offset == 0 && cursor.Size == 0 && !logFileChangedAfterCursor(files[i], cursor) {
+			continue
+		}
 		matches, truncated, errMatch := logFileMatchesCursor(files[i], cursor)
 		if errMatch != nil {
 			if errors.Is(errMatch, os.ErrNotExist) {
@@ -845,6 +854,29 @@ func locateLogCursorFile(files []string, cursor logCursor) (int, bool, error) {
 	return 0, false, nil
 }
 
+func shouldDeferEmptyMainCursorToRotated(files []string, cursor logCursor) bool {
+	if cursor.File != defaultLogFileName || cursor.Offset != 0 || cursor.Size != 0 {
+		return false
+	}
+	for i := range files {
+		if filepath.Base(files[i]) == defaultLogFileName {
+			continue
+		}
+		if logFileChangedAfterCursor(files[i], cursor) {
+			return true
+		}
+	}
+	return false
+}
+
+func logFileChangedAfterCursor(path string, cursor logCursor) bool {
+	info, errStat := os.Stat(path)
+	if errStat != nil || info.IsDir() || info.Size() == 0 {
+		return false
+	}
+	return info.ModTime().UnixNano() > cursorModTimeUnixNano(cursor)
+}
+
 func logFileMatchesCursor(path string, cursor logCursor) (bool, bool, error) {
 	info, errStat := os.Stat(path)
 	if errStat != nil {
@@ -856,7 +888,11 @@ func logFileMatchesCursor(path string, cursor logCursor) (bool, bool, error) {
 	if info.Size() < cursor.Offset {
 		return false, true, nil
 	}
-	fingerprint, errFingerprint := logFileFingerprint(path, cursor.Offset)
+	boundary := cursorFingerprintBoundary(cursor)
+	if info.Size() < boundary {
+		return false, true, nil
+	}
+	fingerprint, errFingerprint := logFileFingerprint(path, boundary)
 	if errFingerprint != nil {
 		return false, false, errFingerprint
 	}
@@ -953,7 +989,11 @@ func newLogCursor(path string, offset, latest int64) (string, error) {
 	if offset < 0 || offset > info.Size() {
 		return "", fmt.Errorf("invalid cursor offset")
 	}
-	fingerprint, errFingerprint := logFileFingerprint(path, offset)
+	fingerprintCursor := logCursor{
+		Offset: offset,
+		Size:   info.Size(),
+	}
+	fingerprint, errFingerprint := logFileFingerprint(path, cursorFingerprintBoundary(fingerprintCursor))
 	if errFingerprint != nil {
 		return "", errFingerprint
 	}
@@ -963,11 +1003,26 @@ func newLogCursor(path string, offset, latest int64) (string, error) {
 		Offset:          offset,
 		Size:            info.Size(),
 		ModTime:         info.ModTime().Unix(),
+		ModTimeUnixNano: info.ModTime().UnixNano(),
 		LatestTimestamp: latest,
 		Fingerprint:     fingerprint,
 	})
 }
 
+func cursorFingerprintBoundary(cursor logCursor) int64 {
+	if cursor.Offset == 0 && cursor.Size > 0 {
+		return cursor.Size
+	}
+	return cursor.Offset
+}
+
+func cursorModTimeUnixNano(cursor logCursor) int64 {
+	if cursor.ModTimeUnixNano > 0 {
+		return cursor.ModTimeUnixNano
+	}
+	return cursor.ModTime * int64(time.Second)
+}
+
 func logFileFingerprint(path string, boundary int64) (string, error) {
 	if boundary < 0 {
 		return "", fmt.Errorf("invalid fingerprint boundary")
diff --git a/internal/api/handlers/management/logs_test.go b/internal/api/handlers/management/logs_test.go
index 1f1056e5..eb38176c 100644
--- a/internal/api/handlers/management/logs_test.go
+++ b/internal/api/handlers/management/logs_test.go
@@ -382,6 +382,80 @@ func TestGetLogsCursorReadsRotatedFileWhenNewMainIsSmaller(t *testing.T) {
 	}
 }
 
+func TestGetLogsZeroOffsetCursorWithPartialLineReadsAcrossRotation(t *testing.T) {
+	dir := t.TempDir()
+	writeMainLog(t, dir, "partial")
+	initial := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=1")
+	if initial.NextCursor == "" {
+		t.Fatal("initial next-cursor is empty")
+	}
+	cursor, errCursor := decodeLogCursor(initial.NextCursor)
+	if errCursor != nil {
+		t.Fatalf("decode initial cursor: %v", errCursor)
+	}
+	if cursor.Offset != 0 || cursor.Size == 0 {
+		t.Fatalf("cursor offset/size = %d/%d, want zero offset with partial size", cursor.Offset, cursor.Size)
+	}
+
+	appendMainLog(t, dir, " complete\n")
+	if err := os.Rename(filepath.Join(dir, defaultLogFileName), filepath.Join(dir, defaultLogFileName+".1")); err != nil {
+		t.Fatalf("rotate main log: %v", err)
+	}
+	writeMainLog(t, dir, "new\n")
+
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(initial.NextCursor)+"&limit=10")
+	wantLines := []string{"partial complete", "new"}
+	if !reflect.DeepEqual(resp.Lines, wantLines) {
+		t.Fatalf("lines = %#v, want %#v", resp.Lines, wantLines)
+	}
+	if resp.CursorReset {
+		t.Fatal("cursor-reset = true, want false")
+	}
+}
+
+func TestGetLogsZeroOffsetCursorWithEmptyFileReadsAcrossRotation(t *testing.T) {
+	dir := t.TempDir()
+	writeMainLog(t, dir, "")
+	initial := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=1")
+	if initial.NextCursor == "" {
+		t.Fatal("initial next-cursor is empty")
+	}
+	cursor, errCursor := decodeLogCursor(initial.NextCursor)
+	if errCursor != nil {
+		t.Fatalf("decode initial cursor: %v", errCursor)
+	}
+	if cursor.Offset != 0 || cursor.Size != 0 {
+		t.Fatalf("cursor offset/size = %d/%d, want empty zero offset", cursor.Offset, cursor.Size)
+	}
+
+	appendMainLog(t, dir, "first\n")
+	mainPath := filepath.Join(dir, defaultLogFileName)
+	nextModTime := time.Unix(0, cursorModTimeUnixNano(cursor)+int64(time.Second))
+	if err := os.Chtimes(mainPath, nextModTime, nextModTime); err != nil {
+		t.Fatalf("update main log mtime: %v", err)
+	}
+	if err := os.Rename(mainPath, filepath.Join(dir, defaultLogFileName+".1")); err != nil {
+		t.Fatalf("rotate main log: %v", err)
+	}
+	writeMainLog(t, dir, "second\n")
+
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(initial.NextCursor)+"&limit=1")
+	if !reflect.DeepEqual(resp.Lines, []string{"first"}) {
+		t.Fatalf("lines = %#v, want first rotated line", resp.Lines)
+	}
+	if resp.CursorReset {
+		t.Fatal("cursor-reset = true, want false")
+	}
+
+	next := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(resp.NextCursor)+"&limit=1")
+	if !reflect.DeepEqual(next.Lines, []string{"second"}) {
+		t.Fatalf("next lines = %#v, want second main line", next.Lines)
+	}
+	if next.CursorReset {
+		t.Fatal("next cursor-reset = true, want false")
+	}
+}
+
 func TestGetLogsInvalidCursorResetsToTail(t *testing.T) {
 	dir := t.TempDir()
 	lines := []string{
-- 
2.51.2


From a47c38631979d4ab4614af3c98ca2808255c0f3a Mon Sep 17 00:00:00 2001
From: LTbinglingfeng <tan13318527080@163.com>
Date: Mon, 15 Jun 2026 15:51:15 +0800
Subject: [PATCH 08/10] Avoid counting all logs for tail reads

---
 internal/api/handlers/management/logs.go      | 67 +------------------
 internal/api/handlers/management/logs_test.go | 22 +++++-
 2 files changed, 21 insertions(+), 68 deletions(-)

diff --git a/internal/api/handlers/management/logs.go b/internal/api/handlers/management/logs.go
index 3dfc635a..6d8477ba 100644
--- a/internal/api/handlers/management/logs.go
+++ b/internal/api/handlers/management/logs.go
@@ -101,12 +101,7 @@ func (h *Handler) GetLogs(c *gin.Context) {
 			c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to read log files: %v", errTail)})
 			return
 		}
-		total, errCount := countLogFileLines(files)
-		if errCount != nil {
-			c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to read log files: %v", errCount)})
-			return
-		}
-		writeLogsResponse(c, result.lines, total, result.latest, result.nextCursor, false)
+		writeLogsResponse(c, result.lines, len(result.lines), result.latest, result.nextCursor, false)
 		return
 	}
 
@@ -612,66 +607,6 @@ func readTailLogLines(path string, limit int) (completeLogRead, error) {
 	return readCompleteLogLines(path, start, boundary, limit)
 }
 
-func countLogFileLines(files []string) (int, error) {
-	total := 0
-	for i := range files {
-		count, errCount := countLogLines(files[i])
-		if errCount != nil {
-			if errors.Is(errCount, os.ErrNotExist) {
-				continue
-			}
-			return 0, errCount
-		}
-		total += count
-	}
-	return total, nil
-}
-
-func countLogLines(path string) (int, error) {
-	file, errOpen := os.Open(path)
-	if errOpen != nil {
-		return 0, errOpen
-	}
-	defer func() {
-		_ = file.Close()
-	}()
-	info, errStat := file.Stat()
-	if errStat != nil {
-		return 0, errStat
-	}
-	if info.IsDir() {
-		return 0, fmt.Errorf("invalid log file")
-	}
-
-	buf := make([]byte, 32*1024)
-	count := 0
-	lineLen := 0
-	for {
-		n, errRead := file.Read(buf)
-		for _, b := range buf[:n] {
-			if b == '\n' {
-				count++
-				lineLen = 0
-				continue
-			}
-			lineLen++
-			if lineLen > logScannerMaxBuffer {
-				return 0, fmt.Errorf("log line exceeds %d bytes", logScannerMaxBuffer)
-			}
-		}
-		if errRead == io.EOF {
-			break
-		}
-		if errRead != nil {
-			return 0, errRead
-		}
-	}
-	if lineLen > 0 {
-		count++
-	}
-	return count, nil
-}
-
 func tailStartOffset(path string, boundary int64, limit int) (int64, error) {
 	if limit <= 0 {
 		return 0, nil
diff --git a/internal/api/handlers/management/logs_test.go b/internal/api/handlers/management/logs_test.go
index eb38176c..34a07c7e 100644
--- a/internal/api/handlers/management/logs_test.go
+++ b/internal/api/handlers/management/logs_test.go
@@ -149,8 +149,8 @@ func TestGetLogsTailLimitReturnsRecentLinesWithCursor(t *testing.T) {
 	if !reflect.DeepEqual(resp.Lines, wantLines) {
 		t.Fatalf("lines = %#v, want %#v", resp.Lines, wantLines)
 	}
-	if resp.LineCount != 4 {
-		t.Fatalf("line-count = %d, want full scan count 4", resp.LineCount)
+	if resp.LineCount != len(wantLines) {
+		t.Fatalf("line-count = %d, want returned line count %d", resp.LineCount, len(wantLines))
 	}
 	if resp.NextCursor == "" {
 		t.Fatal("next-cursor is empty")
@@ -161,6 +161,24 @@ func TestGetLogsTailLimitReturnsRecentLinesWithCursor(t *testing.T) {
 	}
 }
 
+func TestGetLogsTailLimitDoesNotScanOlderFilesForLineCount(t *testing.T) {
+	dir := t.TempDir()
+	rotatedPath := filepath.Join(dir, defaultLogFileName+".1")
+	if err := os.WriteFile(rotatedPath, []byte(strings.Repeat("x", logScannerMaxBuffer+1)+"\n"), 0o644); err != nil {
+		t.Fatalf("write rotated log: %v", err)
+	}
+	writeMainLog(t, dir, "[2026-06-15 10:00:00] current\n")
+
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=1")
+	wantLines := []string{"[2026-06-15 10:00:00] current"}
+	if !reflect.DeepEqual(resp.Lines, wantLines) {
+		t.Fatalf("lines = %#v, want %#v", resp.Lines, wantLines)
+	}
+	if resp.LineCount != len(wantLines) {
+		t.Fatalf("line-count = %d, want returned line count %d", resp.LineCount, len(wantLines))
+	}
+}
+
 func TestGetLogsNoLimitKeepsFullScanBehavior(t *testing.T) {
 	dir := t.TempDir()
 	writeMainLog(t, dir, "complete\npartial")
-- 
2.51.2


From 5036513bf9f6b1f80a5510705db60927b7fbc77b Mon Sep 17 00:00:00 2001
From: LTbinglingfeng <tan13318527080@163.com>
Date: Mon, 15 Jun 2026 16:53:50 +0800
Subject: [PATCH 09/10] Fix ambiguous empty log cursor handling

---
 internal/api/handlers/management/logs.go      | 34 ++++++++++++++
 internal/api/handlers/management/logs_test.go | 47 +++++++++++++++++++
 2 files changed, 81 insertions(+)

diff --git a/internal/api/handlers/management/logs.go b/internal/api/handlers/management/logs.go
index 6d8477ba..ad15a741 100644
--- a/internal/api/handlers/management/logs.go
+++ b/internal/api/handlers/management/logs.go
@@ -31,6 +31,12 @@ const (
 )
 
 // GetLogs returns log lines with optional incremental loading.
+//
+// The legacy timestamp path keeps line-count as the total scanned line count for
+// compatibility. Cursor and tail reads avoid scanning older files, so line-count
+// is the number of returned lines there. A cursor emitted by the legacy path
+// points at the latest complete log boundary; combining after with limit is
+// therefore tail semantics and does not replay lines trimmed by limit.
 func (h *Handler) GetLogs(c *gin.Context) {
 	if h == nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "handler unavailable"})
@@ -756,6 +762,8 @@ func locateLogCursorFile(files []string, cursor logCursor) (int, bool, error) {
 		if matches && !truncated {
 			if shouldDeferEmptyMainCursorToRotated(files, cursor) {
 				deferEmptyMainMatch = true
+			} else if shouldResetAmbiguousEmptyMainCursor(files, index, cursor) {
+				return 0, false, nil
 			} else {
 				return index, true, nil
 			}
@@ -804,6 +812,32 @@ func shouldDeferEmptyMainCursorToRotated(files []string, cursor logCursor) bool
 	return false
 }
 
+func shouldResetAmbiguousEmptyMainCursor(files []string, mainIndex int, cursor logCursor) bool {
+	if cursor.File != defaultLogFileName || cursor.Offset != 0 || cursor.Size != 0 {
+		return false
+	}
+	info, errStat := os.Stat(files[mainIndex])
+	if errStat != nil || info.IsDir() {
+		return false
+	}
+	if info.Size() == cursor.Size && info.ModTime().UnixNano() == cursorModTimeUnixNano(cursor) {
+		return false
+	}
+	for i := range files {
+		if i == mainIndex || filepath.Base(files[i]) == defaultLogFileName {
+			continue
+		}
+		rotatedInfo, errRotated := os.Stat(files[i])
+		if errRotated != nil || rotatedInfo.IsDir() || rotatedInfo.Size() == 0 {
+			continue
+		}
+		if !logFileChangedAfterCursor(files[i], cursor) {
+			return true
+		}
+	}
+	return false
+}
+
 func logFileChangedAfterCursor(path string, cursor logCursor) bool {
 	info, errStat := os.Stat(path)
 	if errStat != nil || info.IsDir() || info.Size() == 0 {
diff --git a/internal/api/handlers/management/logs_test.go b/internal/api/handlers/management/logs_test.go
index 34a07c7e..f803b2cf 100644
--- a/internal/api/handlers/management/logs_test.go
+++ b/internal/api/handlers/management/logs_test.go
@@ -474,6 +474,53 @@ func TestGetLogsZeroOffsetCursorWithEmptyFileReadsAcrossRotation(t *testing.T) {
 	}
 }
 
+func TestGetLogsZeroOffsetCursorWithEmptyFileResetsWhenRotationModTimeAmbiguous(t *testing.T) {
+	dir := t.TempDir()
+	mainPath := filepath.Join(dir, defaultLogFileName)
+	fixedModTime := time.Date(2026, 6, 15, 10, 0, 0, 0, time.Local)
+	writeMainLog(t, dir, "")
+	if err := os.Chtimes(mainPath, fixedModTime, fixedModTime); err != nil {
+		t.Fatalf("set initial main mtime: %v", err)
+	}
+	initial := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=1")
+	if initial.NextCursor == "" {
+		t.Fatal("initial next-cursor is empty")
+	}
+	cursor, errCursor := decodeLogCursor(initial.NextCursor)
+	if errCursor != nil {
+		t.Fatalf("decode initial cursor: %v", errCursor)
+	}
+	if cursor.Offset != 0 || cursor.Size != 0 {
+		t.Fatalf("cursor offset/size = %d/%d, want empty zero offset", cursor.Offset, cursor.Size)
+	}
+
+	first := "[2026-06-15 10:00:01] first"
+	second := "[2026-06-15 10:00:02] second"
+	appendMainLog(t, dir, first+"\n")
+	if err := os.Chtimes(mainPath, fixedModTime, fixedModTime); err != nil {
+		t.Fatalf("set rotated mtime: %v", err)
+	}
+	if err := os.Rename(mainPath, filepath.Join(dir, defaultLogFileName+".1")); err != nil {
+		t.Fatalf("rotate main log: %v", err)
+	}
+	writeMainLog(t, dir, second+"\n")
+	if err := os.Chtimes(mainPath, fixedModTime, fixedModTime); err != nil {
+		t.Fatalf("set new main mtime: %v", err)
+	}
+
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(initial.NextCursor)+"&limit=2")
+	wantLines := []string{first, second}
+	if !reflect.DeepEqual(resp.Lines, wantLines) {
+		t.Fatalf("lines = %#v, want %#v", resp.Lines, wantLines)
+	}
+	if !resp.CursorReset {
+		t.Fatal("cursor-reset = false, want true for ambiguous empty cursor rotation")
+	}
+	if resp.LineCount != len(wantLines) {
+		t.Fatalf("line-count = %d, want returned line count %d", resp.LineCount, len(wantLines))
+	}
+}
+
 func TestGetLogsInvalidCursorResetsToTail(t *testing.T) {
 	dir := t.TempDir()
 	lines := []string{
-- 
2.51.2


From 0b21b0711523448be1432af5a2e0cc148f01996e Mon Sep 17 00:00:00 2001
From: LTbinglingfeng <tan13318527080@163.com>
Date: Mon, 15 Jun 2026 18:37:21 +0800
Subject: [PATCH 10/10] fix log cursor rotation gap

---
 internal/api/handlers/management/logs.go      | 27 +++++++-
 internal/api/handlers/management/logs_test.go | 65 +++++++++++++++++++
 2 files changed, 89 insertions(+), 3 deletions(-)

diff --git a/internal/api/handlers/management/logs.go b/internal/api/handlers/management/logs.go
index ad15a741..b6de20e6 100644
--- a/internal/api/handlers/management/logs.go
+++ b/internal/api/handlers/management/logs.go
@@ -773,13 +773,34 @@ func locateLogCursorFile(files []string, cursor logCursor) (int, bool, error) {
 	if cursor.File != defaultLogFileName || (cursor.Offset == 0 && cursor.Size == 0 && !deferEmptyMainMatch) {
 		return 0, false, nil
 	}
+	if cursor.Offset == 0 && cursor.Size == 0 {
+		for i := range files {
+			if filepath.Base(files[i]) == defaultLogFileName {
+				continue
+			}
+			if !logFileChangedAfterCursor(files[i], cursor) {
+				continue
+			}
+			matches, truncated, errMatch := logFileMatchesCursor(files[i], cursor)
+			if errMatch != nil {
+				if errors.Is(errMatch, os.ErrNotExist) {
+					continue
+				}
+				return 0, false, errMatch
+			}
+			if truncated {
+				continue
+			}
+			if matches {
+				return i, true, nil
+			}
+		}
+		return 0, false, nil
+	}
 	for i := len(files) - 1; i >= 0; i-- {
 		if filepath.Base(files[i]) == defaultLogFileName {
 			continue
 		}
-		if cursor.Offset == 0 && cursor.Size == 0 && !logFileChangedAfterCursor(files[i], cursor) {
-			continue
-		}
 		matches, truncated, errMatch := logFileMatchesCursor(files[i], cursor)
 		if errMatch != nil {
 			if errors.Is(errMatch, os.ErrNotExist) {
diff --git a/internal/api/handlers/management/logs_test.go b/internal/api/handlers/management/logs_test.go
index f803b2cf..8c3e0ead 100644
--- a/internal/api/handlers/management/logs_test.go
+++ b/internal/api/handlers/management/logs_test.go
@@ -474,6 +474,71 @@ func TestGetLogsZeroOffsetCursorWithEmptyFileReadsAcrossRotation(t *testing.T) {
 	}
 }
 
+func TestGetLogsZeroOffsetCursorWithEmptyFileReadsAcrossTwoRotations(t *testing.T) {
+	dir := t.TempDir()
+	writeMainLog(t, dir, "")
+	initial := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?limit=1")
+	if initial.NextCursor == "" {
+		t.Fatal("initial next-cursor is empty")
+	}
+	cursor, errCursor := decodeLogCursor(initial.NextCursor)
+	if errCursor != nil {
+		t.Fatalf("decode initial cursor: %v", errCursor)
+	}
+	if cursor.Offset != 0 || cursor.Size != 0 {
+		t.Fatalf("cursor offset/size = %d/%d, want empty zero offset", cursor.Offset, cursor.Size)
+	}
+
+	mainPath := filepath.Join(dir, defaultLogFileName)
+	firstRotatedPath := filepath.Join(dir, defaultLogFileName+".1")
+	secondRotatedPath := filepath.Join(dir, defaultLogFileName+".2")
+	firstModTime := time.Unix(0, cursorModTimeUnixNano(cursor)+int64(time.Second))
+	secondModTime := time.Unix(0, cursorModTimeUnixNano(cursor)+2*int64(time.Second))
+
+	appendMainLog(t, dir, "first\n")
+	if err := os.Chtimes(mainPath, firstModTime, firstModTime); err != nil {
+		t.Fatalf("update first main log mtime: %v", err)
+	}
+	if err := os.Rename(mainPath, firstRotatedPath); err != nil {
+		t.Fatalf("rotate first main log: %v", err)
+	}
+	writeMainLog(t, dir, "second\n")
+	if err := os.Chtimes(mainPath, secondModTime, secondModTime); err != nil {
+		t.Fatalf("update second main log mtime: %v", err)
+	}
+	if err := os.Rename(firstRotatedPath, secondRotatedPath); err != nil {
+		t.Fatalf("advance first rotated log: %v", err)
+	}
+	if err := os.Rename(mainPath, firstRotatedPath); err != nil {
+		t.Fatalf("rotate second main log: %v", err)
+	}
+	writeMainLog(t, dir, "third\n")
+
+	resp := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(initial.NextCursor)+"&limit=1")
+	if !reflect.DeepEqual(resp.Lines, []string{"first"}) {
+		t.Fatalf("lines = %#v, want oldest rotated line", resp.Lines)
+	}
+	if resp.CursorReset {
+		t.Fatal("cursor-reset = true, want false")
+	}
+
+	next := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(resp.NextCursor)+"&limit=1")
+	if !reflect.DeepEqual(next.Lines, []string{"second"}) {
+		t.Fatalf("next lines = %#v, want newer rotated line", next.Lines)
+	}
+	if next.CursorReset {
+		t.Fatal("next cursor-reset = true, want false")
+	}
+
+	latest := performGetLogs(t, newLogsTestHandler(dir, true), "/v0/management/logs?cursor="+url.QueryEscape(next.NextCursor)+"&limit=1")
+	if !reflect.DeepEqual(latest.Lines, []string{"third"}) {
+		t.Fatalf("latest lines = %#v, want main line", latest.Lines)
+	}
+	if latest.CursorReset {
+		t.Fatal("latest cursor-reset = true, want false")
+	}
+}
+
 func TestGetLogsZeroOffsetCursorWithEmptyFileResetsWhenRotationModTimeAmbiguous(t *testing.T) {
 	dir := t.TempDir()
 	mainPath := filepath.Join(dir, defaultLogFileName)