Struct Queue

pkg/sentry/kernel/msgqueue/msgqueue.go:65–115

Queue represents a SysV message queue, described by sysvipc(7). +stateify savable

//
// +stateify savable
type Queue struct {
	// registry is the registry owning this queue. Immutable.
	registry *Registry

	// mu protects all the fields below.
	mu sync.Mutex `state:"nosave"`

	// dead is set to true when a queue is removed from the registry and should
	// not be used. Operations on the queue should check dead, and return
	// EIDRM if set to true.
	dead bool

	// obj defines basic fields that should be included in all SysV IPC objects.
	obj *ipc.Object

	// senders holds a queue of blocked message senders. Senders are notified
	// when enough space is available in the queue to insert their message.
	senders waiter.Queue

	// receivers holds a queue of blocked receivers. Receivers are notified
	// when a new message is inserted into the queue and can be received.
	receivers waiter.Queue

	// messages is a list of sent messages.
	messages msgList

	// sendTime is the last time a msgsnd was performed.
	sendTime ktime.Time

	// receiveTime is the last time a msgrcv was performed.
	receiveTime ktime.Time

	// changeTime is the last time the queue was modified using msgctl.
	changeTime ktime.Time

	// byteCount is the current number of message bytes in the queue.
	byteCount uint64

	// messageCount is the current number of messages in the queue.
	messageCount uint64

	// maxBytes is the maximum allowed number of bytes in the queue, and is also
	// used as a limit for the number of total possible messages.
	maxBytes uint64

	// sendPID is the PID of the process that performed the last msgsnd.
	sendPID int32

	// receivePID is the PID of the process that performed the last msgrcv.
	receivePID int32
}

// Message represents a message exchanged through a Queue via msgsnd(2) and
// msgrcv(2).