mkdumprd: fix multiple issues with get_ssh_size

Currently get_ssh_size is not working as expected, it should return the
target's available space, but it will include df's header row string as
the result. Fix this issue by only use the last output line.

And the _opt variable will be used as args so it should be an array.

Also remove the awk call, just use `df --output=avail` instead.

Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Philipp Rudo <prudo@redhat.com>

mkdumprd

@@ -94,15 +94,14 @@ to_mount() {
 #$1=dump target
 #called from while loop and shouldn't read from stdin, so we're using "ssh -n"
 get_ssh_size() {
-    local _opt _out
-    _opt="-i $SSH_KEY_LOCATION -o BatchMode=yes -o StrictHostKeyChecking=yes"
-    _out=$(ssh -q -n $_opt $1 "df -P $SAVE_PATH")
-    [ $? -ne 0 ] && {
-        perror_exit "checking remote ssh server available size failed."
-    }
+    local _out
+    local _opt=("-i" "$SSH_KEY_LOCATION" "-o" "BatchMode=yes" "-o" "StrictHostKeyChecking=yes")
 
-    #ssh output removed the line break, so print field NF-2
-    echo -n "$_out" | awk '{avail=NF-2; print $avail}'
+    if ! _out=$(ssh -q -n "${_opt[@]}" "$1" "df" "--output=avail" "$SAVE_PATH"); then
+        perror_exit "checking remote ssh server available size failed."
+    fi
+
+    echo -n "$_out" | tail -1
 }
 
 #mkdir if save path does not exist on ssh dump target