Create mq.Registry and mqfs.RegistryImpl.

Define a POSIX message queue Registry and RegistryImpl in mq package,
implement RegistryImpl in mqfs, and add a Registry object to
IPCNamespace initialized at filesystem creation.

Updates #136

1 files changed, 25 insertions, 0 deletions

diff --git a/pkg/sentry/kernel/ipc_namespace.go b/pkg/sentry/kernel/ipc_namespace.go
index 0b101b1bb..aa9c3fb31 100644
--- a/pkg/sentry/kernel/ipc_namespace.go
+++ b/pkg/sentry/kernel/ipc_namespace.go
@@ -17,6 +17,7 @@ package kernel
 import (
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/mq"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/msgqueue"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/semaphore"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/shm"
@@ -31,9 +32,17 @@ type IPCNamespace struct {
 	// User namespace which owns this IPC namespace. Immutable.
 	userNS *auth.UserNamespace
 
+	// System V utilities.
 	queues     *msgqueue.Registry
 	semaphores *semaphore.Registry
 	shms       *shm.Registry
+
+	// posixQueues is a POSIX message queue registry.
+	//
+	// posixQueues is somewhat equivelant to Linux's ipc_namespace.mq_mnt.
+	// Unlike SysV utilities, mq.Registry is not map-based, but is backed by
+	// a virtual filesystem.
+	posixQueues *mq.Registry
 }
 
 // NewIPCNamespace creates a new IPC namespace.
@@ -63,10 +72,26 @@ func (i *IPCNamespace) ShmRegistry() *shm.Registry {
 	return i.shms
 }
 
+// SetPosixQueues sets value of posixQueues if the value is currently nil,
+// otherwise returns without doing anything.
+func (i *IPCNamespace) SetPosixQueues(r *mq.Registry) {
+	if i.posixQueues == nil {
+		i.posixQueues = r
+	}
+}
+
+// PosixQueues returns the posix message queue registry for this namespace.
+func (i *IPCNamespace) PosixQueues() *mq.Registry {
+	return i.posixQueues
+}
+
 // DecRef implements refsvfs2.RefCounter.DecRef.
 func (i *IPCNamespace) DecRef(ctx context.Context) {
 	i.IPCNamespaceRefs.DecRef(func() {
 		i.shms.Release(ctx)
+		if i.posixQueues != nil {
+			i.posixQueues.Destroy(ctx)
+		}
 	})
 }