proc: bugfix: propagate signals we don't handle to inferior

Fixes #419 (partial)

proc/proc_linux.go

@@ -317,7 +317,10 @@ func (dbp *Process) trapWait(pid int) (*Thread, error) {
 		}
 		if th != nil {
 			// TODO(dp) alert user about unexpected signals here.
-			if err := th.Continue(); err != nil {
+			if err := th.resumeWithSig(int(status.StopSignal())); err != nil {
+				if err == sys.ESRCH {
+					return nil, ProcessExitedError{Pid: dbp.Pid}
+				}
 				return nil, err
 			}
 		}

proc/proc_unix_test.go

@@ -0,0 +1,31 @@
+// +build linux darwin
+
+package proc
+
+import (
+	"testing"
+	"time"
+	"syscall"
+
+	protest "github.com/derekparker/delve/proc/test"
+)
+
+func TestIssue419(t *testing.T) {
+	// SIGINT directed at the inferior should be passed along not swallowed by delve
+	withTestProcess("issue419", t, func(p *Process, fixture protest.Fixture) {
+		go func() {
+			for {
+				if p.Running() {
+					time.Sleep(2 * time.Second)
+					err := syscall.Kill(p.Pid, syscall.SIGINT)
+					assertNoError(err, t, "syscall.Kill")
+					return
+				}
+			}
+		}()
+		err := p.Continue()
+		if _, exited := err.(ProcessExitedError); !exited {
+			t.Fatalf("Unexpected error after Continue(): %v\n", err)
+		}
+	})
+}

proc/threads_linux.go

@@ -33,9 +33,13 @@ func (t *Thread) stopped() bool {
 	return state == StatusTraceStop
 }
 
-func (t *Thread) resume() (err error) {
+func (t *Thread) resume() error {
+	return t.resumeWithSig(0)
+}
+
+func (t *Thread) resumeWithSig(sig int) (err error) {
 	t.running = true
-	t.dbp.execPtraceFunc(func() { err = PtraceCont(t.ID, 0) })
+	t.dbp.execPtraceFunc(func() { err = PtraceCont(t.ID, sig) })
 	return
 }