Fix race between start and destroy

Before this change, a container starting up could race with
destroy (aka delete) and leave processes behind.

Now, whenever a container is created, Loader.processes gets
a new entry. Start now expects the entry to be there, and if
it's not it means that the container was deleted.

I've also fixed Loader.waitPID to search for the process using
the init process's PID namespace.

We could use a few more tests for signal and wait. I'll send
them in another cl.

PiperOrigin-RevId: 220224290
Change-Id: I15146079f69904dc07d43c3b66cc343a2dab4cc4

1 files changed, 19 insertions, 5 deletions

diff --git a/runsc/sandbox/sandbox.go b/runsc/sandbox/sandbox.go
index 9421bd63e..084d79d06 100644
--- a/runsc/sandbox/sandbox.go
+++ b/runsc/sandbox/sandbox.go
@@ -102,6 +102,21 @@ func Create(id string, spec *specs.Spec, conf *boot.Config, bundleDir, consoleSo
 	return s, nil
 }
 
+// CreateContainer creates a non-root container inside the sandbox.
+func (s *Sandbox) CreateContainer(cid string) error {
+	log.Debugf("Create non-root container %q in sandbox %q, PID: %d", cid, s.ID, s.Pid)
+	sandboxConn, err := s.sandboxConnect()
+	if err != nil {
+		return fmt.Errorf("couldn't connect to sandbox: %v", err)
+	}
+	defer sandboxConn.Close()
+
+	if err := sandboxConn.Call(boot.ContainerCreate, &cid, nil); err != nil {
+		return fmt.Errorf("creating non-root container %q: %v", cid, err)
+	}
+	return nil
+}
+
 // StartRoot starts running the root container process inside the sandbox.
 func (s *Sandbox) StartRoot(spec *specs.Spec, conf *boot.Config) error {
 	log.Debugf("Start root sandbox %q, PID: %d", s.ID, s.Pid)
@@ -125,13 +140,13 @@ func (s *Sandbox) StartRoot(spec *specs.Spec, conf *boot.Config) error {
 	return nil
 }
 
-// Start starts running a non-root container inside the sandbox.
-func (s *Sandbox) Start(spec *specs.Spec, conf *boot.Config, cid string, goferFiles []*os.File) error {
+// StartContainer starts running a non-root container inside the sandbox.
+func (s *Sandbox) StartContainer(spec *specs.Spec, conf *boot.Config, cid string, goferFiles []*os.File) error {
 	for _, f := range goferFiles {
 		defer f.Close()
 	}
 
-	log.Debugf("Start non-root container sandbox %q, PID: %d", s.ID, s.Pid)
+	log.Debugf("Start non-root container %q in sandbox %q, PID: %d", cid, s.ID, s.Pid)
 	sandboxConn, err := s.sandboxConnect()
 	if err != nil {
 		return fmt.Errorf("couldn't connect to sandbox: %v", err)
@@ -208,9 +223,8 @@ func (s *Sandbox) Processes(cid string) ([]*control.Process, error) {
 	}
 	defer conn.Close()
 
-	args := boot.ProcessesArgs{CID: cid}
 	var pl []*control.Process
-	if err := conn.Call(boot.ContainerProcesses, &args, &pl); err != nil {
+	if err := conn.Call(boot.ContainerProcesses, &cid, &pl); err != nil {
 		return nil, fmt.Errorf("error retrieving process data from sandbox: %v", err)
 	}
 	return pl, nil