feat: add an equivalent of WaitWrapper for os.Process

For using os.Process in Talos replacing exec.Cmd in some places we need to ba able to use reaper with it.

Signed-off-by: Dmitry Sharshakov <[email protected]>

Author: dsseng

Diff for: pkg/cmd/proc/reaper/reaper_test.go

@@ -188,6 +188,61 @@ func (suite *ReaperSuite) TestWait() {
 	}
 }
 
+func (suite *ReaperSuite) TestProcessWait() {
+	type args struct {
+		name string
+		args []string
+	}
+
+	tests := []struct { //nolint:govet
+		args      args
+		errString string
+	}{
+		{
+			args{
+				"true",
+				[]string{},
+			},
+			"",
+		},
+		{
+			args{
+				"false",
+				[]string{},
+			},
+			"exit status 1",
+		},
+		{
+			args{
+				"/bin/sh",
+				[]string{
+					"-c",
+					"kill -2 $$",
+				},
+			},
+			"signal: interrupt",
+		},
+	}
+
+	notifyCh := make(chan reaper.ProcessInfo, 1)
+
+	suite.Require().True(reaper.Notify(notifyCh))
+	defer reaper.Stop(notifyCh)
+
+	for _, t := range tests {
+		cmd := exec.Command(t.args.name, t.args.args...)
+		suite.Require().NoError(cmd.Start())
+
+		err := reaper.ProcessWaitWrapper(true, notifyCh, cmd.Process)
+
+		if t.errString == "" {
+			suite.Assert().NoError(err)
+		} else {
+			suite.Assert().EqualError(err, t.errString)
+		}
+	}
+}
+
 func TestReaperSuite(t *testing.T) {
 	suite.Run(t, new(ReaperSuite))
 }

Diff for: pkg/cmd/proc/reaper/wait.go

@@ -6,6 +6,7 @@ package reaper
 
 import (
 	"fmt"
+	"os"
 	"os/exec"
 	"syscall"
 )
@@ -37,6 +38,36 @@ func WaitWrapper(usingReaper bool, notifyCh <-chan ProcessInfo, cmd *exec.Cmd) e
 	return err
 }
 
+// ProcessWaitWrapper emulates os/exec.Process.Wait() when reaper is running.
+// It is equivalent to WaitWrapper
+//
+// ProcessWaitWrapper(true, proc) should be equivalent to proc.Wait().
+func ProcessWaitWrapper(usingReaper bool, notifyCh <-chan ProcessInfo, proc *os.Process) error {
+	if !usingReaper {
+		_, waitErr := proc.Wait()
+
+		return waitErr
+	}
+
+	var info ProcessInfo
+
+	for info = range notifyCh {
+		if info.Pid == proc.Pid && (info.Status.Exited() || info.Status.Signaled()) {
+			break
+		}
+	}
+
+	err := convertWaitStatus(info.Status)
+
+	// release any resources
+	waitErr := proc.Release()
+	if err == nil && waitErr != nil && waitErr.Error() != "waitid: no child processes" {
+		err = waitErr
+	}
+
+	return err
+}
+
 // ExitError is raised when exit status is not equal to 0.
 type ExitError struct {
 	ExitCode int