When attaching to a container, hijack puts the terminal in raw mode,
and local echo is disabled. In normal cases, the terminal is restored
once the container detaches;
6f856263c2/cli/command/container/hijack.go (L40-L44)
However, when the CLI is forced to exit (after 3 signals), we `os.Exit(1)`,
which causes defers to not be executed, and because of this, the terminal
not being restored.
For example; start a container that's attached;
docker run -it --rm --sig-proxy=false alpine sleep 20
In another terminal send a SIGINT 3 times to force terminate;
kill -sINT $(pgrep -af docker\ run)
kill -sINT $(pgrep -af docker\ run)
kill -sINT $(pgrep -af docker\ run)
The first terminal shows that the docker cli was terminated;
got 3 SIGTERM/SIGINTs, forcefully exiting
However, the terminal was not restored, so local echo is disabled, and
typing any command in the terminal does not show output (a manual `stty echo`
is needed to restore).
With this patch, the terminal is restored before we forcefully exit the
docker CLI. Restoring is a no-op if there's no previous state, so we
can unconditionally execute this.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>