Add bouncer MOTD

Closes: https://todo.sr.ht/~emersion/soju/137

cmd/soju/main.go

@@ -5,6 +5,7 @@ import (
 	"crypto/tls"
 	"flag"
 	"fmt"
+	"io/ioutil"
 	"log"
 	"net"
 	"net/http"
@@ -36,6 +37,19 @@ func (v *stringSliceFlag) Set(s string) error {
 	return nil
 }
 
+func loadMOTD(srv *soju.Server, filename string) error {
+	if filename == "" {
+		return nil
+	}
+
+	b, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return err
+	}
+	srv.SetMOTD(strings.TrimSpace(string(b)))
+	return nil
+}
+
 func main() {
 	var listen []string
 	var configPath string
@@ -91,6 +105,10 @@ func main() {
 	srv.MaxUserNetworks = cfg.MaxUserNetworks
 	srv.Debug = debug
 
+	if err := loadMOTD(srv, cfg.MOTDPath); err != nil {
+		log.Fatalf("failed to load MOTD: %v", err)
+	}
+
 	for _, listen := range cfg.Listen {
 		listenURI := listen
 		if !strings.Contains(listenURI, ":/") {
@@ -224,8 +242,8 @@ func main() {
 	for sig := range sigCh {
 		switch sig {
 		case syscall.SIGHUP:
+			log.Print("reloading TLS certificate and MOTD")
 			if cfg.TLS != nil {
-				log.Print("reloading TLS certificate")
 				cert, err := tls.LoadX509KeyPair(cfg.TLS.CertPath, cfg.TLS.KeyPath)
 				if err != nil {
 					log.Printf("failed to reload TLS certificate and key: %v", err)
@@ -233,6 +251,9 @@ func main() {
 				}
 				tlsCert.Store(&cert)
 			}
+			if err := loadMOTD(srv, cfg.MOTDPath); err != nil {
+				log.Printf("failed to reload MOTD: %v", err)
+			}
 		case syscall.SIGINT, syscall.SIGTERM:
 			log.Print("shutting down server")
 			srv.Shutdown()

config/config.go

@@ -40,6 +40,7 @@ type Server struct {
 	Listen   []string
 	Hostname string
 	TLS      *TLS
+	MOTDPath string
 
 	SQLDriver string
 	SQLSource string
@@ -128,6 +129,10 @@ func parse(cfg scfg.Block) (*Server, error) {
 			if srv.MaxUserNetworks, err = strconv.Atoi(max); err != nil {
 				return nil, fmt.Errorf("directive %q: %v", d.Name, err)
 			}
+		case "motd":
+			if err := d.ParseParams(&srv.MOTDPath); err != nil {
+				return nil, err
+			}
 		default:
 			return nil, fmt.Errorf("unknown directive %q", d.Name)
 		}

doc/soju.1.scd

@@ -44,7 +44,8 @@ soju supports two connection modes:
 For per-client history to work, clients need to indicate their name. This can
 be done by adding a "@<client>" suffix to the username.
 
-soju will reload the TLS certificate and key when it receives the HUP signal.
+soju will reload the TLS certificate/key and the MOTD file when it receives the
+HUP signal.
 
 Administrators can broadcast a message to all bouncer users via _/notice
 $<hostname> <text>_, or via _/notice $\* <text>_ in multi-upstream mode. All
@@ -142,6 +143,10 @@ The following directives are supported:
 *max-user-networks* <limit>
 	Maximum number of networks per user. By default, there is no limit.
 
+*motd* <path>
+	Path to the MOTD file. The bouncer MOTD is sent to clients which aren't
+	bound to a specific network. By default, no MOTD is sent.
+
 # IRC SERVICE
 
 soju exposes an IRC service called *BouncerServ* to manage the bouncer.

downstream.go

@@ -1119,20 +1119,29 @@ func (dc *downstreamConn) welcome() error {
 	for _, msg := range generateIsupport(dc.srv.prefix(), dc.nick, isupport) {
 		dc.SendMessage(msg)
 	}
-	motdHint := "No MOTD"
 	if uc := dc.upstream(); uc != nil {
-		motdHint = "Use /motd to read the message of the day"
 		dc.SendMessage(&irc.Message{
 			Prefix:  dc.srv.prefix(),
 			Command: irc.RPL_UMODEIS,
 			Params:  []string{dc.nick, string(uc.modes)},
 		})
 	}
-	dc.SendMessage(&irc.Message{
-		Prefix:  dc.srv.prefix(),
-		Command: irc.ERR_NOMOTD,
-		Params:  []string{dc.nick, motdHint},
-	})
+
+	if motd := dc.user.srv.MOTD(); motd != "" && dc.network == nil {
+		for _, msg := range generateMOTD(dc.srv.prefix(), dc.nick, motd) {
+			dc.SendMessage(msg)
+		}
+	} else {
+		motdHint := "No MOTD"
+		if dc.network != nil {
+			motdHint = "Use /motd to read the message of the day"
+		}
+		dc.SendMessage(&irc.Message{
+			Prefix:  dc.srv.prefix(),
+			Command: irc.ERR_NOMOTD,
+			Params:  []string{dc.nick, motdHint},
+		})
+	}
 
 	dc.updateNick()
 	dc.updateRealname()

irc.go

@@ -379,6 +379,31 @@ func generateIsupport(prefix *irc.Prefix, nick string, tokens []string) []*irc.M
 	return msgs
 }
 
+func generateMOTD(prefix *irc.Prefix, nick string, motd string) []*irc.Message {
+	var msgs []*irc.Message
+	msgs = append(msgs, &irc.Message{
+		Prefix:  prefix,
+		Command: irc.RPL_MOTDSTART,
+		Params:  []string{nick, fmt.Sprintf("- Message of the Day -")},
+	})
+
+	for _, l := range strings.Split(motd, "\n") {
+		msgs = append(msgs, &irc.Message{
+			Prefix:  prefix,
+			Command: irc.RPL_MOTD,
+			Params:  []string{nick, l},
+		})
+	}
+
+	msgs = append(msgs, &irc.Message{
+		Prefix:  prefix,
+		Command: irc.RPL_ENDOFMOTD,
+		Params:  []string{nick, "End of /MOTD command."},
+	})
+
+	return msgs
+}
+
 type joinSorter struct {
 	channels []string
 	keys     []string

server.go

@@ -63,10 +63,12 @@ type Server struct {
 	lock      sync.Mutex
 	listeners map[net.Listener]struct{}
 	users     map[string]*user
+
+	motd atomic.Value // string
 }
 
 func NewServer(db Database) *Server {
-	return &Server{
+	srv := &Server{
 		Logger:          log.New(log.Writer(), "", log.LstdFlags),
 		HistoryLimit:    1000,
 		MaxUserNetworks: -1,
@@ -74,6 +76,8 @@ func NewServer(db Database) *Server {
 		listeners:       make(map[net.Listener]struct{}),
 		users:           make(map[string]*user),
 	}
+	srv.motd.Store("")
+	return srv
 }
 
 func (s *Server) prefix() *irc.Prefix {
@@ -268,3 +272,11 @@ func (s *Server) Stats() *ServerStats {
 	stats.Downstreams = atomic.LoadInt64(&s.connCount)
 	return &stats
 }
+
+func (s *Server) SetMOTD(motd string) {
+	s.motd.Store(motd)
+}
+
+func (s *Server) MOTD() string {
+	return s.motd.Load().(string)
+}