config: deprecate NoXX-Options

ngircd unfortunately uses several options using double-negation, e.g.

NoIdent = No, NoPam = No, etc.

This renames all options by dropping the "No" prefix, e.g.
"NoIdent = no" becomes "Ident = yes".

The old options will continue to work, but will cause a warning
message.

Also update man pages and default config.

To prevent silly
'Ident = yes' from appearing in  --configtest output in the
'ident support not compiled in and Ident Option not used' case,
make default value depend on feature availability.
If feature is available, enable by default, otherwise disable.

We might consider moving these options to a new
[Feature]

section, or something like that, because none of these options are
essential.

Another possible improvement:

'Ident = yes' option in ngircd.conf causes a warning if ngircd was
built without ident support.

This does not happen with e.g. zeroconf....

src/ngircd/client.c

@@ -93,7 +93,7 @@ Client_Init( void )
 	This_Server->hops = 0;
 
 	gethostname( This_Server->host, CLIENT_HOST_LEN );
-	if (!Conf_NoDNS) {
+	if (Conf_DNS) {
 		h = gethostbyname( This_Server->host );
 		if (h) strlcpy(This_Server->host, h->h_name, sizeof(This_Server->host));
 	}

src/ngircd/conf.c

@@ -341,10 +341,10 @@ Conf_Test( void )
 	printf("  OperServerMode = %s\n", yesno_to_str(Conf_OperServerMode));
 	printf("  AllowRemoteOper = %s\n", yesno_to_str(Conf_AllowRemoteOper));
 	printf("  PredefChannelsOnly = %s\n", yesno_to_str(Conf_PredefChannelsOnly));
-	printf("  NoDNS = %s\n", yesno_to_str(Conf_NoDNS));
-	printf("  NoIdent = %s\n", yesno_to_str(Conf_NoIdent));
-	printf("  NoPAM = %s\n", yesno_to_str(Conf_NoPAM));
-	printf("  NoZeroConf = %s\n", yesno_to_str(Conf_NoZeroConf));
+	printf("  DNS = %s\n", yesno_to_str(Conf_DNS));
+	printf("  Ident = %s\n", yesno_to_str(Conf_Ident));
+	printf("  PAM = %s\n", yesno_to_str(Conf_PAM));
+	printf("  ZeroConf = %s\n", yesno_to_str(Conf_ZeroConf));
 
 #ifdef WANT_IPV6
 	printf("  ConnectIPv4 = %s\n", yesno_to_str(Conf_ConnectIPv6));
@@ -561,6 +561,27 @@ Conf_IsService(int ConfServer, const char *Nick)
 } /* Conf_IsService */
 
 
+static void
+Set_Defaults_Optional(void)
+{
+#ifdef IDENTAUTH
+	Conf_Ident = true;
+#else
+	Conf_Ident = false;
+#endif
+#ifdef PAM
+	Conf_PAM = true;
+#else
+	Conf_PAM = false;
+#endif
+#ifdef ZEROCONF
+	Conf_ZeroConf = true;
+#else
+	Conf_ZeroConf = false;
+#endif
+}
+
+
 /**
  * Initialize configuration settings with their default values.
  */
@@ -591,10 +612,7 @@ Set_Defaults(bool InitServers)
 	Conf_PingTimeout = 120;
 	Conf_PongTimeout = 20;
 	Conf_ConnectRetry = 60;
-	Conf_NoDNS = false;
-	Conf_NoIdent = false;
-	Conf_NoPAM = false;
-	Conf_NoZeroConf = false;
+	Conf_DNS = true;
 
 	Conf_Oper_Count = 0;
 	Conf_Channel_Count = 0;
@@ -619,6 +637,7 @@ Set_Defaults(bool InitServers)
 	Conf_SyslogFacility = 0;
 #endif
 #endif
+	Set_Defaults_Optional();
 
 	/* Initialize server configuration structures */
 	if (InitServers) {
@@ -873,6 +892,53 @@ Handle_MaxNickLength(int Line, const char *Arg)
 } /* Handle_MaxNickLength */
 
 
+static void
+WarnIdent(int Line)
+{
+#ifndef IDENTAUTH
+	if (Conf_Ident) {
+		/* user has enabled ident lookups explicitly, but ... */
+		Config_Error(LOG_WARNING,
+			"%s: line %d: Ident=True, but ngircd was built without IDENT support",
+			NGIRCd_ConfFile, Line);
+	}
+#endif
+}
+
+static bool
+CheckLegacyNoOption(const char *Var, const char *Arg)
+{
+	if( strcasecmp( Var, "NoDNS" ) == 0 ) {
+		Conf_DNS = !Check_ArgIsTrue( Arg );
+		return true;
+	}
+	if (strcasecmp(Var, "NoIdent") == 0) {
+		Conf_Ident = !Check_ArgIsTrue(Arg);
+		return true;
+	}
+	if(strcasecmp(Var, "NoPAM") == 0) {
+		Conf_PAM = !Check_ArgIsTrue(Arg);
+		return true;
+	}
+	if(strcasecmp(Var, "NoZeroConf") == 0) {
+		Conf_ZeroConf = !Check_ArgIsTrue(Arg);
+		return true;
+	}
+	return false;
+}
+
+const char *
+NoNo(const char *str)
+{
+	assert(strncasecmp("no", str, 2) == 0 && str[2]);
+	return str + 2;
+}
+
+static const char *
+InvertArg(const char *arg)
+{
+	return yesno_to_str(!Check_ArgIsTrue(arg));
+}
 
 static void
 Handle_GLOBAL( int Line, char *Var, char *Arg )
@@ -1036,32 +1102,34 @@ Handle_GLOBAL( int Line, char *Var, char *Arg )
 		Conf_PredefChannelsOnly = Check_ArgIsTrue( Arg );
 		return;
 	}
-	if( strcasecmp( Var, "NoDNS" ) == 0 ) {
-		/* don't do reverse dns lookups when clients connect? */
-		Conf_NoDNS = Check_ArgIsTrue( Arg );
+
+	if (CheckLegacyNoOption(Var, Arg)) {
+		Config_Error(LOG_WARNING, "%s, line %d: \"No\"-Prefix has been removed, use "
+				"\"%s = %s\" instead",
+					NGIRCd_ConfFile, Line, NoNo(Var), InvertArg(Arg));
+		if (strcasecmp(Var, "NoIdent") == 0)
+			WarnIdent(Line);
 		return;
 	}
-	if (strcasecmp(Var, "NoIdent") == 0) {
-		/* don't do IDENT lookups when clients connect? */
-		Conf_NoIdent = Check_ArgIsTrue(Arg);
-#ifndef IDENTAUTH
-		if (!Conf_NoIdent) {
-			/* user has enabled ident lookups explicitly, but ... */
-			Config_Error(LOG_WARNING,
-				"%s: line %d: NoIdent=False, but ngircd was built without IDENT support",
-				NGIRCd_ConfFile, Line);
-		}
-#endif
+	if( strcasecmp( Var, "DNS" ) == 0 ) {
+		/* do reverse dns lookups when clients connect? */
+		Conf_DNS = Check_ArgIsTrue( Arg );
 		return;
 	}
-	if(strcasecmp(Var, "NoPAM") == 0) {
-		/* don't use PAM library to authenticate users */
-		Conf_NoPAM = Check_ArgIsTrue(Arg);
+	if (strcasecmp(Var, "Ident") == 0) {
+		/* do IDENT lookups when clients connect? */
+		Conf_Ident = Check_ArgIsTrue(Arg);
+		WarnIdent(Line);
 		return;
 	}
-	if(strcasecmp(Var, "NoZeroConf") == 0) {
-		/* don't register services using ZeroConf */
-		Conf_NoZeroConf = Check_ArgIsTrue(Arg);
+	if(strcasecmp(Var, "PAM") == 0) {
+		/* use PAM library to authenticate users */
+		Conf_PAM = Check_ArgIsTrue(Arg);
+		return;
+	}
+	if(strcasecmp(Var, "ZeroConf") == 0) {
+		/* register services using ZeroConf */
+		Conf_ZeroConf = Check_ArgIsTrue(Arg);
 		return;
 	}
 #ifdef WANT_IPV6

src/ngircd/conf.h

@@ -143,17 +143,17 @@ GLOBAL bool Conf_OperServerMode;
 /* Are remote IRC operators allowed to manage this server? */
 GLOBAL bool Conf_AllowRemoteOper;
 
-/* Disable all DNS functions? */
-GLOBAL bool Conf_NoDNS;
+/* Enable all DNS functions? */
+GLOBAL bool Conf_DNS;
 
-/* Disable IDENT lookups, even when compiled with support for it */
-GLOBAL bool Conf_NoIdent;
+/* Enable IDENT lookups, even when compiled with support for it */
+GLOBAL bool Conf_Ident;
 
-/* Disable all usage of PAM, even when compiled with support for it */
-GLOBAL bool Conf_NoPAM;
+/* Enable all usage of PAM, even when compiled with support for it */
+GLOBAL bool Conf_PAM;
 
-/* Disable service registration using "ZeroConf" */
-GLOBAL bool Conf_NoZeroConf;
+/* Enable service registration using "ZeroConf" */
+GLOBAL bool Conf_ZeroConf;
 
 /*
  * try to connect to remote systems using the ipv6 protocol,

src/ngircd/conn.c

@@ -1381,10 +1381,10 @@ New_Connection(int Sock)
 
 	identsock = new_sock;
 #ifdef IDENTAUTH
-	if (Conf_NoIdent)
+	if (!Conf_Ident)
 		identsock = -1;
 #endif
-	if (!Conf_NoDNS)
+	if (Conf_DNS)
 		Resolve_Addr(&My_Connections[new_sock].proc_stat, &new_addr,
 			     identsock, cb_Read_Resolver_Result);
 

src/ngircd/irc-login.c

@@ -778,7 +778,7 @@ Hello_User(CLIENT * Client)
 	assert(Client != NULL);
 	conn = Client_Conn(Client);
 
-	if (Conf_NoPAM) {
+	if (!Conf_PAM) {
 		/* Don't do any PAM authentication at all, instead emulate
 		 * the beahiour of the daemon compiled without PAM support:
 		 * because there can't be any "server password", all

src/ngircd/rendezvous.c

@@ -151,7 +151,7 @@ GLOBAL bool Rendezvous_Register( char *Name, char *Type, UINT16 Port )
 {
 	int i;
 
-	if (Conf_NoZeroConf)
+	if (!Conf_ZeroConf)
 		return true;
 
 	/* Search free port structure */