[FEATURE #190] Save old ssh host keys and authorized_keys during firmware upgrade

and restore to new firwmare.

userspace/rootfs_override/etc/init.d/wrs-boot-procedure

@@ -182,7 +182,25 @@ fi
 
 # First: update usr: we may have the whole thing, or just wrs-usr.tar.gz
 if [ -f /update/$WRS_FW -o -f /update/$WRS_USR ]; then
+    echo -n "Saving existing data..." | $TEE /dev/ttyGS0
+
+    # Mount /usr temporarily to transfer some existing files
+    mkdir -p /usr
+    mount -t ubifs ubi0:usr /usr
+
+    # save some old data to be reused with updated software
+    if ls /usr/etc/ssh/ssh_host_*_key* 1> /dev/null 2>&1; then
+        cp /usr/etc/ssh/ssh_host_*_key* /tmp/
+    fi
+    if [ -f /usr/authorized_keys ]; then
+        cp /usr/authorized_keys /tmp/
+    fi
     # FIXME: save configuration somewhere, and recover it later
+
+    # Unmount /usr again so we can recreate the partition form the new firmware
+    sync; cd /; umount /usr
+    echo " done" | $TEE /dev/ttyGS0
+
     echo -n "Extracting filesystem..." | $TEE /dev/ttyGS0
     # since we are upgrading, we'd better remove and recreate the volume
     ubirmvol /dev/ubi0 --name=usr
@@ -195,6 +213,17 @@ if [ -f /update/$WRS_FW -o -f /update/$WRS_USR ]; then
     else
 	tar xzf /update/$WRS_USR
     fi
+    echo " done" | $TEE /dev/ttyGS0
+
+
+    # restore saved data
+    echo -n "Restoring saved data..." | $TEE /dev/ttyGS0
+    if ls /tmp/ssh_host_*_key* 1> /dev/null 2>&1; then
+        mv /tmp/ssh_host_*_key* /usr/etc/ssh/
+    fi
+    if [ -f /tmp/authorized_keys ]; then
+        mv /tmp/authorized_keys /usr/
+    fi
 
     sync; cd /; umount /usr
     echo " done" | $TEE /dev/ttyGS0