uboot-envtools: check for config prior to append

In the rare event a pre-populated fw_env.config exists in the rootfs prior
to firstboot, calling fw_setenv after the system has initialised will
annihilate the devices environment due to two identical lines in
fw_env.config.

Check for existence prior to blind appendage.

Signed-off-by: Imran Khan <gururug@gmail.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
[daniel@makrotopia.org: fixed patch format, improved grep, cosmetics]

package/boot/uboot-envtools/Makefile

@@ -10,7 +10,7 @@ include $(TOPDIR)/rules.mk
 PKG_NAME:=uboot-envtools
 PKG_DISTNAME:=u-boot
 PKG_VERSION:=2019.07
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE:=$(PKG_DISTNAME)-$(PKG_VERSION).tar.xz

package/boot/uboot-envtools/files/uboot-envtools.sh

@@ -31,6 +31,6 @@ ubootenv_add_app_config() {
 	config_get envsize "$1" envsize
 	config_get secsize "$1" secsize
 	config_get numsec "$1" numsec
-	echo "$dev $offset $envsize $secsize $numsec" >>/etc/fw_env.config
+	grep -q "^[[:space:]]*${dev}[[:space:]]*${offset}" /etc/fw_env.config || echo "$dev $offset $envsize $secsize $numsec" >>/etc/fw_env.config
 }