customize: virtual packages for build configuration

This is a loose collection of virtual packages which when built,
tweak the final image.

It's mostly a workaround to overlay's going away.

Signed-off-by: Philip Prindeville <philipp@redfish-solutions.com>

admin/customize/Makefile

@@ -0,0 +1,97 @@
+#
+# Copyright (C) 2018 Philip Prindeville
+#
+# This is free software, licensed under the GNU General Public License v3 or
+# later.
+#
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=customize
+PKG_VERSION:=1.0
+PKG_RELEASE:=1
+PKG_LICENSE:=GPLv3
+
+PKG_MAINTAINER:=Philip Prindeville <philipp@redfish-solutions.com>
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/customize/Default
+  SECTION:=admin
+  CATEGORY:=Administration
+endef
+
+define Package/customize/description
+  Customize your target system.
+endef
+
+define Package/customize/download
+endef
+
+define Build/Prepare
+endef
+
+define Build/Configure
+endef
+
+define Build/Compile
+
+endef
+
+define Package/root-passwd
+$(call Package/customize/Default)
+  TITLE:=Set default root password
+endef
+
+define Package/root-passwd/description
+  Use this package to seed your images with a preset root password.
+endef
+
+define Package/root-passwd/config
+	config TARGET_ROOT_PASSWD
+		string "Default root password (hashed, with dollars doubled up)"
+		help
+			Default root password.
+endef
+
+define Package/root-passwd/install
+   # nothing to do
+endef
+
+ROOT_PASSWD:=$(call qstrip,$(CONFIG_TARGET_ROOT_PASSWD))
+
+define Package/root-passwd/postinst
+#!/bin/sh
+if [ -n "$$IPKG_INSTROOT" ] && [ -n "$(ROOT_PASSWD)" ]; then
+    $(SED) 's/^root::0:/root:$(ROOT_PASSWD)::/' $$IPKG_INSTROOT/etc/shadow
+fi
+exit 0
+endef
+
+define Package/disable-openssh-password-login
+$(call Package/customize/Default)
+  TITLE:=Turn off password logins via openssh
+  DEPENDS+= @(PACKAGE_openssh-server||PACKAGE_openssh-server-pam)
+endef
+
+define Package/disable-openssh-password-login/description
+  Change default openssh server setting to disallow password logins (and
+  thereby mitigate possible password attacks)
+endef
+
+define Package/disable-openssh-password-login/install
+  # nothing to do
+endef
+
+define Package/disable-openssh-password-login/postinst
+#!/bin/sh
+if [ -n "$$IPKG_INSTROOT" ]; then
+  $(SED) 's/#PasswordAuthentication yes$$/PasswordAuthentication no/' \
+	$$IPKG_INSTROOT/etc/ssh/sshd_config
+fi
+exit 0
+endef
+
+$(eval $(call BuildPackage,root-passwd))
+$(eval $(call BuildPackage,disable-openssh-password-login))
+