msm8953-common: Fix MBN copy issue

DAC_OVERRIDE is disabled for all the vendor init scripts
in Android P. This change will grant "group root" the write
permission temporarily for deleting/copying operations.

System user could not access the MBN files in data partition
no longer. Only radio user and root group have read permission
after boot up.

Change-Id: I9f184da2253dc5896b145c0e52fc3b42da15d9f7

rootdir/init.qcom.rc

@@ -273,7 +273,7 @@ on post-fs-data
     mkdir /data/vendor/radio 0770 system radio
 
     # Create directory for modem_config
-    mkdir /data/vendor/modem_config 0550 system radio
+    mkdir /data/vendor/modem_config 0570 radio root
 
     # Mounting of persist is moved to 'on emmc-fs' and 'on fs' sections
     # We chown/chmod /persist again so because mount is run as root + defaults

rootdir/init.qcom.sh

@@ -354,6 +354,8 @@ fi
 
 cur_version_info=`cat /firmware/verinfo/ver_info.txt`
 if [ ! -f /firmware/verinfo/ver_info.txt -o "$prev_version_info" != "$cur_version_info" ]; then
+    # add W for group recursively before delete
+    chmod g+w -R /data/vendor/modem_config/*
     rm -rf /data/vendor/modem_config/*
     # preserve the read only mode for all subdir and files
     cp --preserve=m -dr /firmware/image/modem_pr/mcfg/configs/* /data/vendor/modem_config
@@ -361,8 +363,10 @@ if [ ! -f /firmware/verinfo/ver_info.txt -o "$prev_version_info" != "$cur_versio
     cp --preserve=m -d /firmware/image/modem_pr/mbn_ota.txt /data/vendor/modem_config/
     cp --preserve=m -d /firmware/image/modem_pr/mbn_oin.txt /data/vendor/modem_config/
     cp --preserve=m -d /firmware/image/modem_pr/mbn_ogl.txt /data/vendor/modem_config/
-    chown -hR radio.radio /data/vendor/modem_config/*
+    # the group must be root, otherwise this script could not add "W" for group recursively
+    chown -hR radio.root /data/vendor/modem_config/*
 fi
+chmod g-w /data/vendor/modem_config
 setprop ro.runtime.mbn_copy_completed 1
 
 #check build variant for printk logging