Force use shadow, even if missing.

etc/login.defs

@@ -393,3 +393,8 @@ USERGROUPS_ENAB yes
 #
 #CREATE_HOME     yes
 
+#
+# Force use shadow, even if shadow passwd & shadow group files are
+# missing.
+#
+#FORCE_SHADOW    yes

lib/getdef.c

@@ -139,6 +139,7 @@ static struct itemdef def_table[] = {
 	{"TCB_SYMLINKS", NULL},
 	{"USE_TCB", NULL},
 #endif
+	{"FORCE_SHADOW", NULL},
 	{NULL, NULL}
 };
 

lib/sgroupio.c

@@ -249,6 +249,8 @@ int sgr_setdbname (const char *filename)
 
 bool sgr_file_present (void)
 {
+	if (getdef_bool ("FORCE_SHADOW"))
+		return true;
 	return commonio_present (&gshadow_db);
 }
 

lib/shadowio.c

@@ -125,6 +125,8 @@ int spw_setdbname (const char *filename)
 
 bool spw_file_present (void)
 {
+	if (getdef_bool ("FORCE_SHADOW"))
+		return true;
 	return commonio_present (&shadow_db);
 }