restore terminal when terminating after 3 signals

[thaJeztah]

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;

cli/cli/command/container/hijack.go

Lines 40 to 44 in 6f85626

	func (h *hijackedIOStreamer) stream(ctx context.Context) error {
	restoreInput, err := h.setupInput()
	if err != nil {
	return fmt.Errorf("unable to setup input stream: %s", err)
	}

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.

- Human readable description for the release notes

Make sure the terminal state is restored if the CLI is forcefully terminated.

- A picture of a cute animal (not mandatory but encouraged)

[Copilot]

Pull Request Overview

This PR ensures that the terminal is restored to its previous state when the Docker CLI is forcefully terminated after receiving three termination signals.

• Added a call to restore the terminal state in both the plugin termination logic and the force-exit function.
• Changed the parameter type from io.Writer to command.Streams in forceExitAfter3TerminationSignals and removed an unused import.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 13 lines in your changes missing coverage. Please review.

Project coverage is 59.05%. Comparing base (6f85626) to head (a17b9c5).

❌ Your patch status has failed because the patch coverage (0.00%) is below the target coverage (50.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6058      +/-   ##
==========================================
- Coverage   59.07%   59.05%   -0.02%     
==========================================
  Files         358      358              
  Lines       30013    30023      +10     
==========================================
  Hits        17731    17731              
- Misses      11301    11311      +10     
  Partials      981      981              

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