streamer/audio: fixed a race condition in the BufferRead.Read method

templates: fixed race conditions in the template reloading logic

streamer/audio/buffer.go

@@ -3,7 +3,6 @@ package audio
 import (
 	"io"
 	"sync"
-	"sync/atomic"
 )
 
 type AudioFormat struct {
@@ -93,44 +92,43 @@ func (b *Buffer) Error() (err error) {
 // Reader returns a reader over the data contained in the buffer
 func (b *Buffer) Reader() *BufferReader {
 	return &BufferReader{
-		mu:     b.mu.RLocker(),
-		parent: b,
+		parentMu: b.mu.RLocker(),
+		parent:   b,
 	}
 }
 
 // BufferReader is an io.Reader on top of a Buffer, multiple readers per
 // Buffer can be created
 type BufferReader struct {
+	mu sync.Mutex
 	// pos is the position of this reader in parent.buf
 	pos uint64
 
 	// mu is an inherited lock from the parent and should be locked when
 	// accessing the protected parent fields
-	mu sync.Locker
+	parentMu sync.Locker
 	// parent is the Buffer of this reader
 	parent *Buffer
 }
 
 func (br *BufferReader) Read(p []byte) (n int, err error) {
-	br.mu.Lock()
-
-	if br.pos == uint64(len(br.parent.buf)) {
-		if !br.parent.isClosed {
-			br.parent.cond.Wait()
-		} else if br.parent.err != nil {
-			err = br.parent.err
-			br.mu.Unlock()
-			return 0, err
+	br.mu.Lock() // write lock for ourselves
+	defer br.mu.Unlock()
+	br.parentMu.Lock() // read lock for parent
+	defer br.parentMu.Unlock()
+
+	for br.pos == uint64(len(br.parent.buf)) {
+		if br.parent.err != nil {
+			return 0, br.parent.err
+		}
+		if br.parent.isClosed {
+			return 0, io.EOF
 		}
-	}
 
-	n = copy(p, br.parent.buf[br.pos:])
-	if br.parent.isClosed && n == 0 {
-		br.mu.Unlock()
-		return 0, io.EOF
+		br.parent.cond.Wait()
 	}
 
-	atomic.AddUint64(&br.pos, uint64(n))
-	br.mu.Unlock()
+	n = copy(p, br.parent.buf[br.pos:])
+	br.pos += uint64(n)
 	return n, nil
 }

streamer/audio/mp3_encode.go

@@ -1,3 +1,4 @@
+//go:build !nolame
 // +build !nolame
 
 package audio

templates/loader.go

@@ -60,6 +60,9 @@ func (s *Site) Executor() *Executor {
 }
 
 func (s *Site) ThemeNames() []string {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
 	keys := maps.Keys(s.themes)
 	slices.Sort(keys)
 	return keys
@@ -123,13 +126,19 @@ func (s *Site) prodTemplate(theme, page string) (*template.Template, error) {
 }
 
 func (s *Site) Theme(name string) ThemeBundle {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
 	if ps, ok := s.themes[name]; ok {
 		return ps
 	}
 	return s.themes[DEFAULT_DIR]
 }
 
 func (s *Site) ResolveThemeName(name string) string {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
 	if _, ok := s.themes[name]; ok {
 		return name
 	}