Implement stringer for ExitStatus

PiperOrigin-RevId: 377370807

pkg/sentry/kernel/task_exit.go

@@ -28,6 +28,7 @@ import (
 	"errors"
 	"fmt"
 	"strconv"
+	"strings"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
@@ -50,6 +51,23 @@ type ExitStatus struct {
 	Signo int
 }
 
+func (es ExitStatus) String() string {
+	var b strings.Builder
+	if code := es.Code; code != 0 {
+		if b.Len() != 0 {
+			b.WriteByte(' ')
+		}
+		_, _ = fmt.Fprintf(&b, "Code=%d", code)
+	}
+	if signal := es.Signo; signal != 0 {
+		if b.Len() != 0 {
+			b.WriteByte(' ')
+		}
+		_, _ = fmt.Fprintf(&b, "Signal=%d", signal)
+	}
+	return b.String()
+}
+
 // Signaled returns true if the ExitStatus indicates that the exiting task or
 // thread group was killed by a signal.
 func (es ExitStatus) Signaled() bool {