iop: ssh_upgrade: Use ssh instead of scp

Use SSH with a pipe to transfer the file and invoke sysupgrade in one
go. Using SSH instead of SCP gives a higher throughput (not very
noticable for small files like the ones we use for sysupgrade, though),
but using only one command invocation saves a significant overhead of
TCP and SSH connection setup.

The main reason for this change is though that OpenSSH 9.0 and later
use SFTP instead of the scp protocol when using the scp command in an
effort of deprecating the very clunky legacy SCP protocol. One can use
scp -O to continue using scp, but switching to ssh only has other
benefits outlined above.

Signed-off-by: Andreas Gnau <andreas.gnau@iopsys.eu>

iop/scripts/iopupgrade.sh

@@ -285,9 +285,12 @@ function ssh_upgrade {
 	[ $upd_noreboot -eq 1 ] && extra_args="$extra_args -d"
 	[ $upd_keepconf -eq 0 ] && extra_args="$extra_args -n"
 
-	scp $upd_fw root@$upd_host:/tmp/ &&
-		ssh -o ConnectTimeout=60 root@$upd_host "sysupgrade -v $extra_args /tmp/$upd_fw_base" &&
-		echo "sysupgrade done!"
+	pv "$upd_fw" |
+		ssh \
+			-o ConnectTimeout=60 \
+			root@"$upd_host" \
+			sh -c "cat > '/tmp/$upd_fw_base' && (set -x && sysupgrade -v $extra_args /tmp/$upd_fw_base)" ||
+		echo "Sysupgrade failed" >&2 && return 1
 }
 
 register_command "ssh_upgrade" "-h <host> -f <file> [opts]  Install firmware on remote host with SSH"