Pattern search the user input in a file in Unix using awk

I am trying to write awk script to search for a patte that is given input by user, in a file.
My code look like this:
awk 'BEGIN{printf "Enter : ";getline input<"/dev/tty"} /'"$input"'/ {print}' <abc.txt
What I get as an output is the whole file. Can someone help me to find where I'm going wrong ?