allow overriding services hostname

Fixes #1407

default.yaml

@@ -337,6 +337,10 @@ server:
     # to the working directory. set this to customize:
     #output-path: "/home/oragono/out"
 
+    # the hostname used by "services", e.g., NickServ, defaults to "localhost",
+    # e.g., `NickServ!NickServ@localhost`. uncomment this to override:
+    #override-services-hostname: "example.network"
+
 # account options
 accounts:
     # is account authentication enabled, i.e., can users log into existing accounts?

irc/config.go

@@ -537,6 +537,7 @@ type Config struct {
 		EnforceUtf8              bool         `yaml:"enforce-utf8"`
 		OutputPath               string       `yaml:"output-path"`
 		IPCheckScript            ScriptConfig `yaml:"ip-check-script"`
+		OverrideServicesHostname string       `yaml:"override-services-hostname"`
 	}
 
 	Roleplay struct {

irc/server.go

@@ -530,6 +530,8 @@ func (server *Server) applyConfig(config *Config) (err error) {
 		} else if oldConfig.Server.IPCheckScript.MaxConcurrency != config.Server.IPCheckScript.MaxConcurrency ||
 			oldConfig.Accounts.AuthScript.MaxConcurrency != config.Accounts.AuthScript.MaxConcurrency {
 			return fmt.Errorf("Cannot change max-concurrency for scripts after launching the server, rehash aborted")
+		} else if oldConfig.Server.OverrideServicesHostname != config.Server.OverrideServicesHostname {
+			return fmt.Errorf("Cannot change override-services-hostname after launching the server, rehash aborted")
 		}
 	}
 
@@ -563,6 +565,10 @@ func (server *Server) applyConfig(config *Config) (err error) {
 		if maxAuthConc != 0 {
 			server.semaphores.AuthScript.Initialize(maxAuthConc)
 		}
+
+		if err := overrideServicePrefixes(config.Server.OverrideServicesHostname); err != nil {
+			return err
+		}
 	}
 
 	if oldConfig != nil {

irc/services.go

@@ -316,6 +316,19 @@ func makeServiceHelpTextGenerator(cmd string, banner string) func(*Client) strin
 	}
 }
 
+func overrideServicePrefixes(hostname string) error {
+	if hostname == "" {
+		return nil
+	}
+	if !utils.IsHostname(hostname) {
+		return fmt.Errorf("`%s` is an invalid services hostname", hostname)
+	}
+	for _, serv := range OragonoServices {
+		serv.prefix = fmt.Sprintf("%s!%s@%s", serv.Name, serv.Name, hostname)
+	}
+	return nil
+}
+
 func initializeServices() {
 	// this modifies the global Commands map,
 	// so it must be called from irc/commands.go's init()

traditional.yaml

@@ -309,6 +309,10 @@ server:
     # to the working directory. set this to customize:
     #output-path: "/home/oragono/out"
 
+    # the hostname used by "services", e.g., NickServ, defaults to "localhost",
+    # e.g., `NickServ!NickServ@localhost`. uncomment this to override:
+    #override-services-hostname: "example.network"
+
 # account options
 accounts:
     # is account authentication enabled, i.e., can users log into existing accounts?