term: remove interrupt handler on termios

On termios platforms, interrupt signals are not generated in raw mode
terminals as the ISIG setting is not enabled. Remove interrupt handler
as it does nothing for raw mode and prevents other uses of INT signal
with this library.

This code seems to go back all the way to moby/moby#214 where signal
handling was improved for monolithic docker repository. Raw mode -ISIG
got reintroduced in moby/moby@3f63b878076, but the INT handler was left
behind.

Signed-off-by: Sami Loone <[email protected]>

term.go

@@ -6,10 +6,8 @@ package term
 
 import (
 	"errors"
-	"fmt"
 	"io"
 	"os"
-	"os/signal"
 
 	"golang.org/x/sys/unix"
 )
@@ -81,7 +79,6 @@ func DisableEcho(fd uintptr, state *State) error {
 	if err := tcset(fd, &newState); err != nil {
 		return err
 	}
-	handleInterrupt(fd, state)
 	return nil
 }
 
@@ -93,7 +90,6 @@ func SetRawTerminal(fd uintptr) (*State, error) {
 	if err != nil {
 		return nil, err
 	}
-	handleInterrupt(fd, oldState)
 	return oldState, err
 }
 
@@ -103,18 +99,3 @@ func SetRawTerminal(fd uintptr) (*State, error) {
 func SetRawTerminalOutput(fd uintptr) (*State, error) {
 	return nil, nil
 }
-
-func handleInterrupt(fd uintptr, state *State) {
-	sigchan := make(chan os.Signal, 1)
-	signal.Notify(sigchan, os.Interrupt)
-	go func() {
-		for range sigchan {
-			// quit cleanly and the new terminal item is on a new line
-			fmt.Println()
-			signal.Stop(sigchan)
-			close(sigchan)
-			RestoreTerminal(fd, state)
-			os.Exit(1)
-		}
-	}()
-}