Detection of interactive session fixed for systemd user services (#246)

Co-authored-by: Pavel Bazika <pavel.bazika@icewarp.com>

service_linux.go

@@ -6,6 +6,8 @@ package service
 
 import (
 	"bufio"
+	"fmt"
+	"io/ioutil"
 	"os"
 	"strings"
 )
@@ -63,13 +65,37 @@ func init() {
 	)
 }
 
+func binaryName(pid int) (string, error) {
+	statPath := fmt.Sprintf("/proc/%d/stat", pid)
+	dataBytes, err := ioutil.ReadFile(statPath)
+	if err != nil {
+		return "", err
+	}
+
+	// First, parse out the image name
+	data := string(dataBytes)
+	binStart := strings.IndexRune(data, '(') + 1
+	binEnd := strings.IndexRune(data[binStart:], ')')
+	return data[binStart : binStart+binEnd], nil
+}
+
 func isInteractive() (bool, error) {
-	// TODO: This is not true for user services.
 	inContainer, err := isInContainer(cgroupFile)
 	if err != nil {
 		return false, err
 	}
-	return os.Getppid() != 1 || inContainer, nil
+
+	if inContainer {
+		return true, nil
+	}
+
+	ppid := os.Getppid()
+	if ppid == 1 {
+		return false, nil
+	}
+
+	binary, _ := binaryName(ppid)
+	return binary != "systemd", nil
 }
 
 // isInContainer checks if the service is being executed in docker or lxc