From a57c8ab1be36d720cab93c1f899fd563856ef0a6 Mon Sep 17 00:00:00 2001
From: Eric Ernst <eric_ernst@apple.com>
Date: Mon, 26 Apr 2021 12:32:37 -0700
Subject: [PATCH] qemu: kill virtiofsd if failure to start VMM

If the QEMU VMM fails to launch, we currently fail to kill virtiofsd,
resulting in leftover processes running on the host. Let's make sure we
kill these, and explicitly cleanup the virtiofs socket on the
filesystem.

Ideally we'll migrate QEMU to utilize the same virtiofsd interface that
CLH uses, but let's fix this bug as a first step.

Fixes: #1755

Signed-off-by: Eric Ernst <eric_ernst@apple.com>
---
 src/runtime/virtcontainers/qemu.go | 31 +++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/src/runtime/virtcontainers/qemu.go b/src/runtime/virtcontainers/qemu.go
index 3c8ff0249f..0ec40b05e6 100644
--- a/src/runtime/virtcontainers/qemu.go
+++ b/src/runtime/virtcontainers/qemu.go
@@ -710,6 +710,28 @@ func (q *qemu) setupVirtiofsd(ctx context.Context) (err error) {
 	return err
 }
 
+func (q *qemu) stopVirtiofsd(ctx context.Context) (err error) {
+
+	// kill virtiofsd
+	if q.state.VirtiofsdPid == 0 {
+		return errors.New("invalid virtiofsd PID(0)")
+	}
+
+	err = syscall.Kill(q.state.VirtiofsdPid, syscall.SIGKILL)
+	if err != nil {
+		return err
+	}
+	q.state.VirtiofsdPid = 0
+
+	// remove virtiofsd socket
+	sockPath, err := q.vhostFSSocketPath(q.id)
+	if err != nil {
+		return err
+	}
+
+	return os.Remove(sockPath)
+}
+
 func (q *qemu) getMemArgs() (bool, string, string, error) {
 	share := false
 	target := ""
@@ -830,6 +852,14 @@ func (q *qemu) startSandbox(ctx context.Context, timeout int) error {
 		if err != nil {
 			return err
 		}
+		defer func() {
+			if err != nil {
+				if shutdownErr := q.stopVirtiofsd(ctx); shutdownErr != nil {
+					q.Logger().WithError(shutdownErr).Warn("failed to stop virtiofsd")
+				}
+			}
+		}()
+
 	}
 
 	var strErr string
@@ -841,7 +871,6 @@ func (q *qemu) startSandbox(ctx context.Context, timeout int) error {
 				strErr += string(b)
 			}
 		}
-
 		q.Logger().WithError(err).Errorf("failed to launch qemu: %s", strErr)
 		return fmt.Errorf("failed to launch qemu: %s, error messages from qemu log: %s", err, strErr)
 	}