Recover from bbolt panics on corrupted database

When bbolt encounters corrupted page data at runtime, it panics
instead of returning an error. Wrap all DB transactions with
recover to catch these panics, delete the corrupted database
file, and reopen a fresh one.

experimental/cachefile/cache.go

@@ -45,6 +45,7 @@ type CacheFile struct {
 	storeRDRC         bool
 	rdrcTimeout       time.Duration
 	DB                *bbolt.DB
+	resetAccess       sync.Mutex
 	saveMetadataTimer *time.Timer
 	saveFakeIPAccess  sync.RWMutex
 	saveDomain        map[netip.Addr]string
@@ -169,13 +170,55 @@ func (c *CacheFile) Close() error {
 	return c.DB.Close()
 }
 
+func (c *CacheFile) view(fn func(tx *bbolt.Tx) error) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			c.resetDB()
+			err = E.New("database corrupted: ", r)
+		}
+	}()
+	return c.DB.View(fn)
+}
+
+func (c *CacheFile) batch(fn func(tx *bbolt.Tx) error) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			c.resetDB()
+			err = E.New("database corrupted: ", r)
+		}
+	}()
+	return c.DB.Batch(fn)
+}
+
+func (c *CacheFile) update(fn func(tx *bbolt.Tx) error) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			c.resetDB()
+			err = E.New("database corrupted: ", r)
+		}
+	}()
+	return c.DB.Update(fn)
+}
+
+func (c *CacheFile) resetDB() {
+	c.resetAccess.Lock()
+	defer c.resetAccess.Unlock()
+	c.DB.Close()
+	os.Remove(c.path)
+	db, err := bbolt.Open(c.path, 0o666, &bbolt.Options{Timeout: time.Second})
+	if err == nil {
+		_ = filemanager.Chown(c.ctx, c.path)
+		c.DB = db
+	}
+}
+
 func (c *CacheFile) StoreFakeIP() bool {
 	return c.storeFakeIP
 }
 
 func (c *CacheFile) LoadMode() string {
 	var mode string
-	c.DB.View(func(t *bbolt.Tx) error {
+	c.view(func(t *bbolt.Tx) error {
 		bucket := t.Bucket(bucketMode)
 		if bucket == nil {
 			return nil
@@ -193,7 +236,7 @@ func (c *CacheFile) LoadMode() string {
 }
 
 func (c *CacheFile) StoreMode(mode string) error {
-	return c.DB.Batch(func(t *bbolt.Tx) error {
+	return c.batch(func(t *bbolt.Tx) error {
 		bucket, err := t.CreateBucketIfNotExists(bucketMode)
 		if err != nil {
 			return err
@@ -230,7 +273,7 @@ func (c *CacheFile) createBucket(t *bbolt.Tx, key []byte) (*bbolt.Bucket, error)
 
 func (c *CacheFile) LoadSelected(group string) string {
 	var selected string
-	c.DB.View(func(t *bbolt.Tx) error {
+	c.view(func(t *bbolt.Tx) error {
 		bucket := c.bucket(t, bucketSelected)
 		if bucket == nil {
 			return nil
@@ -245,7 +288,7 @@ func (c *CacheFile) LoadSelected(group string) string {
 }
 
 func (c *CacheFile) StoreSelected(group, selected string) error {
-	return c.DB.Batch(func(t *bbolt.Tx) error {
+	return c.batch(func(t *bbolt.Tx) error {
 		bucket, err := c.createBucket(t, bucketSelected)
 		if err != nil {
 			return err
@@ -255,7 +298,7 @@ func (c *CacheFile) StoreSelected(group, selected string) error {
 }
 
 func (c *CacheFile) LoadGroupExpand(group string) (isExpand bool, loaded bool) {
-	c.DB.View(func(t *bbolt.Tx) error {
+	c.view(func(t *bbolt.Tx) error {
 		bucket := c.bucket(t, bucketExpand)
 		if bucket == nil {
 			return nil
@@ -271,7 +314,7 @@ func (c *CacheFile) LoadGroupExpand(group string) (isExpand bool, loaded bool) {
 }
 
 func (c *CacheFile) StoreGroupExpand(group string, isExpand bool) error {
-	return c.DB.Batch(func(t *bbolt.Tx) error {
+	return c.batch(func(t *bbolt.Tx) error {
 		bucket, err := c.createBucket(t, bucketExpand)
 		if err != nil {
 			return err
@@ -286,7 +329,7 @@ func (c *CacheFile) StoreGroupExpand(group string, isExpand bool) error {
 
 func (c *CacheFile) LoadRuleSet(tag string) *adapter.SavedBinary {
 	var savedSet adapter.SavedBinary
-	err := c.DB.View(func(t *bbolt.Tx) error {
+	err := c.view(func(t *bbolt.Tx) error {
 		bucket := c.bucket(t, bucketRuleSet)
 		if bucket == nil {
 			return os.ErrNotExist
@@ -304,7 +347,7 @@ func (c *CacheFile) LoadRuleSet(tag string) *adapter.SavedBinary {
 }
 
 func (c *CacheFile) SaveRuleSet(tag string, set *adapter.SavedBinary) error {
-	return c.DB.Batch(func(t *bbolt.Tx) error {
+	return c.batch(func(t *bbolt.Tx) error {
 		bucket, err := c.createBucket(t, bucketRuleSet)
 		if err != nil {
 			return err