add support for HTTP over unix sockets

This adds support for using unix scheme in xxxAddress config options.
For example `hlsAddress: "unix://hls.sock"`.

internal/protocols/httpp/server.go

@@ -8,6 +8,8 @@ import (
 	"log"
 	"net"
 	"net/http"
+	"os"
+	"strings"
 	"time"
 
 	"github.com/bluenviron/mediamtx/internal/certloader"
@@ -61,12 +63,26 @@ func (s *Server) Initialize() error {
 		}
 	}
 
+	if strings.HasPrefix(s.Network, "tcp") {
+		var isunix bool
+		s.Address, isunix = strings.CutPrefix(s.Address, "unix://")
+		if isunix {
+			s.Network = "unix"
+		}
+
+		os.Remove(s.Address)
+	}
+
 	var err error
 	s.ln, err = net.Listen(s.Network, s.Address)
 	if err != nil {
 		return err
 	}
 
+	if s.Network == "unix" {
+		os.Chmod(s.Address, 0775)
+	}
+
 	h := s.Handler
 	h = &handlerFilterRequests{h}
 	h = &handlerFilterRequests{h}

internal/protocols/httpp/server_test.go

@@ -36,3 +36,17 @@ func TestFilterEmptyPath(t *testing.T) {
 	_, err = io.ReadFull(conn, buf)
 	require.NoError(t, err)
 }
+
+func TestUnixSocket(t *testing.T) {
+	s := &Server{
+		Network:     "tcp",
+		Address:     "unix://http.sock",
+		ReadTimeout: 10 * time.Second,
+		Parent:      test.NilLogger,
+	}
+	err := s.Initialize()
+	require.NoError(t, err)
+	defer s.Close()
+
+	require.Equal(t, s.Network, "unix")
+}