Function Msgctl

pkg/sentry/syscalls/linux/sys_msgqueue.go:124–187

Msgctl implements msgctl(2).

(t *kernel.Task, sysno uintptr, args arch.SyscallArguments)

// Msgctl implements msgctl(2).
func Msgctl(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
	id := ipc.ID(args[0].Int())
	cmd := args[1].Int()
	buf := args[2].Pointer()

	creds := auth.CredentialsFromContext(t)

	r := t.IPCNamespace().MsgqueueRegistry()

	switch cmd {
	case linux.IPC_INFO:
		info := r.IPCInfo(t)
		_, err := info.CopyOut(t, buf)
		return 0, nil, err
	case linux.MSG_INFO:
		msgInfo := r.MsgInfo(t)
		_, err := msgInfo.CopyOut(t, buf)
		return 0, nil, err
	case linux.IPC_RMID:
		return 0, nil, r.Remove(id, creds)
	}

	// Remaining commands use a queue.
	queue, err := r.FindByID(id)
	if err != nil {
		return 0, nil, err
	}

	switch cmd {
	case linux.MSG_STAT:
		// Technically, we should be treating id as "an index into the kernel's
		// internal array that maintains information about all shared memory
		// segments on the system". Since we don't track segments in an array,
		// we'll just pretend the msqid is the index and do the same thing as
		// IPC_STAT. Linux also uses the index as the msqid.
		fallthrough
	case linux.IPC_STAT:
		stat, err := queue.Stat(t)
		if err != nil {
			return 0, nil, err
		}
		_, err = stat.CopyOut(t, buf)
		return 0, nil, err

	case linux.MSG_STAT_ANY:
		stat, err := queue.StatAny(t)
		if err != nil {
			return 0, nil, err
		}
		_, err = stat.CopyOut(t, buf)
		return 0, nil, err

	case linux.IPC_SET:
		var ds linux.MsqidDS
		if _, err := ds.CopyIn(t, buf); err != nil {
			return 0, nil, linuxerr.EINVAL
		}
		err := queue.Set(t, &ds)