dns: add configure option "--with-config-dns-rc-manager-default" for default of main.rc-managerth/dns-rc-manager-default-rh1337222

Downstream might want to choose a different default value for
main.rc-manager setting.

Make the default configurable at build-time and also embed it into
the manual page of "NetworkManager.conf".

https://bugzilla.redhat.com/show_bug.cgi?id=1337222

4 files changed, 45 insertions, 46 deletions

diff --git a/configure.ac b/configure.ac
index 50384f320e..dbcc024572 100644
--- a/configure.ac
+++ b/configure.ac
@@ -779,6 +779,11 @@ fi
 # resolvconf and netconfig support
 AC_ARG_WITH(resolvconf, AS_HELP_STRING([--with-resolvconf=yes|no|path], [Enable resolvconf support]))
 AC_ARG_WITH(netconfig, AS_HELP_STRING([--with-netconfig=yes|no], [Enable SUSE netconfig support]))
+AC_ARG_WITH(config-dns-rc-manager-default, AS_HELP_STRING([--with-config-dns-rc-manager-default=symlink|file|netconfig|resolvconf], [Configure default value for main.rc-manager setting]), [config_dns_rc_manager_default=$withval])
+if test "$config_dns_rc_manager_default" != symlink -a "$config_dns_rc_manager_default" != file -a "$config_dns_rc_manager_default" != netconfig -a "$config_dns_rc_manager_default" != resolvconf; then
+	AC_MSG_WARN([Unknown --with-config-dns-rc-manager-default=$config_dns_rc_manager_default setting.])
+	config_dns_rc_manager_default=
+fi
 # Use netconfig by default on SUSE
 AS_IF([test -z "$with_netconfig"], AC_CHECK_FILE(/etc/SuSE-release, with_netconfig=yes))
 # Otherwise default to "no"
@@ -788,9 +793,16 @@ AS_IF([test -z "$with_netconfig"], with_netconfig=no)
 if test "$with_resolvconf" = "yes"; then
 	AC_PATH_PROGS(with_resolvconf, resolvconf, no, /sbin:/usr/sbin:/usr/local/sbin)
 fi
+if test "$with_resolvconf" != "no"; then
+	AS_IF([test -z "$config_dns_rc_manager_default"], config_dns_rc_manager_default=resolvconf)
+fi
 if test "$with_netconfig" = "yes"; then
 	AC_PATH_PROGS(with_netconfig, netconfig, no, /sbin:/usr/sbin:/usr/local/sbin)
 fi
+if test "$with_netconfig" != "no"; then
+	AS_IF([test -z "$config_dns_rc_manager_default"], config_dns_rc_manager_default=netconfig)
+fi
+AS_IF([test -z "$config_dns_rc_manager_default"], config_dns_rc_manager_default=symlink)
 # Define resolvconf and netconfig paths
 if test "$with_resolvconf" != "no"; then
 	AC_DEFINE_UNQUOTED(RESOLVCONF_PATH, "$with_resolvconf", [Path to resolvconf])
@@ -798,6 +810,8 @@ fi
 if test "$with_netconfig" != "no"; then
 	AC_DEFINE_UNQUOTED(NETCONFIG_PATH, "$with_netconfig", [Path to netconfig])
 fi
+AC_DEFINE_UNQUOTED(NM_CONFIG_DEFAULT_DNS_RC_MANAGER, "$config_dns_rc_manager_default", [Default value for main.rc-manager setting (--with-config-dns-rc-manager-default)])
+AC_SUBST(NM_CONFIG_DEFAULT_DNS_RC_MANAGER, $config_dns_rc_manager_default)
 
 # iptables path
 AC_ARG_WITH(iptables, AS_HELP_STRING([--with-iptables=/path/to/iptables], [path to iptables]))
@@ -1190,6 +1204,7 @@ echo
 echo "Handlers for /etc/resolv.conf:"
 echo "  resolvconf: ${with_resolvconf}"
 echo "  netconfig: ${with_netconfig}"
+echo "  config-dns-rc-manager-default: ${config_dns_rc_manager_default}"
 echo
 
 echo "DHCP clients:"
diff --git a/man/NetworkManager.conf.xml b/man/NetworkManager.conf.xml
index 56d5e259bc..3035d6054a 100644
--- a/man/NetworkManager.conf.xml
+++ b/man/NetworkManager.conf.xml
@@ -312,7 +312,9 @@ no-auto-default=*
         <term><varname>rc-manager</varname></term>
         <listitem><para>Set the <filename>resolv.conf</filename>
         management mode. The default value depends on how NetworkManager
-        was built. Regardless of this setting, NetworkManager will
+        was built, whereas this version of NetworkManager was build with
+        a default of "<literal>&NM_CONFIG_DEFAULT_DNS_RC_MANAGER;</literal>".
+        Regardless of this setting, NetworkManager will
         always write resolv.conf to its runtime state directory.</para>
         <para><literal>symlink</literal>: NetworkManager will symlink
         <filename>/etc/resolv.conf</filename> to its private
diff --git a/man/common.ent.in b/man/common.ent.in
index ae8897eb8a..ec91e8a6a2 100644
--- a/man/common.ent.in
+++ b/man/common.ent.in
@@ -4,3 +4,4 @@
 <!ENTITY NM_CONFIG_DEFAULT_AUTH_POLKIT_TEXT "@NM_CONFIG_DEFAULT_AUTH_POLKIT_TEXT@">
 <!ENTITY NM_CONFIG_LOGGING_BACKEND_DEFAULT_TEXT "@NM_CONFIG_LOGGING_BACKEND_DEFAULT_TEXT@">
 <!ENTITY NM_CONFIG_DEFAULT_LOGGING_AUDIT_TEXT "@NM_CONFIG_DEFAULT_LOGGING_AUDIT_TEXT@">
+<!ENTITY NM_CONFIG_DEFAULT_DNS_RC_MANAGER "@NM_CONFIG_DEFAULT_DNS_RC_MANAGER@">
diff --git a/src/dns-manager/nm-dns-manager.c b/src/dns-manager/nm-dns-manager.c
index 45d17deedd..bc2d4c66bb 100644
--- a/src/dns-manager/nm-dns-manager.c
+++ b/src/dns-manager/nm-dns-manager.c
@@ -67,15 +67,11 @@ G_DEFINE_TYPE (NMDnsManager, nm_dns_manager, G_TYPE_OBJECT)
 
 #define HASH_LEN 20
 
-#ifdef RESOLVCONF_PATH
-#define RESOLVCONF_SELECTED
-#else
+#ifndef RESOLVCONF_PATH
 #define RESOLVCONF_PATH "/sbin/resolvconf"
 #endif
 
-#ifdef NETCONFIG_PATH
-#define NETCONFIG_SELECTED
-#else
+#ifndef NETCONFIG_PATH
 #define NETCONFIG_PATH "/sbin/netconfig"
 #endif
 
@@ -1482,41 +1478,6 @@ _clear_plugin (NMDnsManager *self)
 	return FALSE;
 }
 
-static NMDnsManagerResolvConfManager
-_get_resolv_conf_manager_default (void)
-{
-#if defined(RESOLVCONF_SELECTED)
-	return NM_DNS_MANAGER_RESOLV_CONF_MAN_RESOLVCONF;
-#elif defined(NETCONFIG_SELECTED)
-	return NM_DNS_MANAGER_RESOLV_CONF_MAN_NETCONFIG;
-#else
-	return NM_DNS_MANAGER_RESOLV_CONF_MAN_SYMLINK;
-#endif
-}
-
-static NMDnsManagerResolvConfManager
-_get_resolv_conf_manager (NMConfig *config)
-{
-	const char *man;
-
-	man = nm_config_data_get_rc_manager (nm_config_get_data (config));
-	if (!man)
-		return _get_resolv_conf_manager_default ();
-
-	if (NM_IN_STRSET (man, "symlink", "none"))
-		return NM_DNS_MANAGER_RESOLV_CONF_MAN_SYMLINK;
-	if (nm_streq (man, "file"))
-		return NM_DNS_MANAGER_RESOLV_CONF_MAN_FILE;
-	if (nm_streq (man, "resolvconf"))
-		return NM_DNS_MANAGER_RESOLV_CONF_MAN_RESOLVCONF;
-	if (nm_streq (man, "netconfig"))
-		return NM_DNS_MANAGER_RESOLV_CONF_MAN_NETCONFIG;
-	if (nm_streq (man, "unmanaged"))
-		return NM_DNS_MANAGER_RESOLV_CONF_MAN_UNMANAGED;
-
-	return NM_DNS_MANAGER_RESOLV_CONF_MAN_UNKNOWN;
-}
-
 static bool
 _get_resconf_immutable (void)
 {
@@ -1549,11 +1510,31 @@ init_resolv_conf_mode (NMDnsManager *self)
 	else if (_get_resconf_immutable ())
 		rc_manager = NM_DNS_MANAGER_RESOLV_CONF_MAN_IMMUTABLE;
 	else {
-		rc_manager = _get_resolv_conf_manager (priv->config);
+		const char *man;
+
+		rc_manager = NM_DNS_MANAGER_RESOLV_CONF_MAN_UNKNOWN;
+		man = nm_config_data_get_rc_manager (nm_config_get_data (priv->config));
+
+again:
+		if (!man) {
+			/* nop */
+		} else if (NM_IN_STRSET (man, "symlink", "none"))
+			rc_manager = NM_DNS_MANAGER_RESOLV_CONF_MAN_SYMLINK;
+		else if (nm_streq (man, "file"))
+			rc_manager = NM_DNS_MANAGER_RESOLV_CONF_MAN_FILE;
+		else if (nm_streq (man, "resolvconf"))
+			rc_manager = NM_DNS_MANAGER_RESOLV_CONF_MAN_RESOLVCONF;
+		else if (nm_streq (man, "netconfig"))
+			rc_manager = NM_DNS_MANAGER_RESOLV_CONF_MAN_NETCONFIG;
+		else if (nm_streq (man, "unmanaged"))
+			rc_manager = NM_DNS_MANAGER_RESOLV_CONF_MAN_UNMANAGED;
+
 		if (rc_manager == NM_DNS_MANAGER_RESOLV_CONF_MAN_UNKNOWN) {
-			_LOGW ("init: unknown resolv.conf manager '%s'",
-			       nm_config_data_get_rc_manager (nm_config_get_data (priv->config)));
-			rc_manager = _get_resolv_conf_manager_default ();
+			_LOGW ("init: unknown resolv.conf manager %s%s%s, fallback to \"%s\"",
+			       NM_PRINT_FMT_QUOTE_STRING (man), ""NM_CONFIG_DEFAULT_DNS_RC_MANAGER);
+			man = ""NM_CONFIG_DEFAULT_DNS_RC_MANAGER;
+			rc_manager = NM_DNS_MANAGER_RESOLV_CONF_MAN_SYMLINK;
+			goto again;
 		}
 	}