I start /opt/cni/bin/dhcp daemon as described at https://www.cni.dev/plugins/current/ipam/dhcp/ . The file-socket /run/cni/dhcp.sock is created by the process . I stop the process with Ctrl+C. The file-socket /run/cni/dhcp.sock is still there. I call again /opt/cni/bin/dhcp daemon, which prints:

2022/07/24 17:56:32 Error getting listener: listen unix /run/cni/dhcp.sock: bind: address already in use

lsof shows that /run/cni/dhcp.sock is not in use. That said, on Ctrl+C dhcp daemon shall delete /run/cni/dhcp.sock which it created on start up, or reuse on startup. No normal process under linux creates files on startup, which it does not clean by itself, and refuses to start the next time, if the files are present