class KthreadListDumpCmd(gdb.Command):
    """Prints the kthread list"""

    def __init__(self):
        super(KthreadListDumpCmd, self).__init__(
            "kthread_list_dump", gdb.COMMAND_USER
        )

    def _kthread_list_to_str(self, val):
        """Walk through the Kthread list.

        We will simply follow the 'next' pointers until we encounter the HEAD again
        """
        idx = 0
        head = val
        kthread_ptr = val
        result = ""
        while kthread_ptr != 0 and (idx == 0 or kthread_ptr != head) :
            name = kthread_ptr["name"]
            result += "\n%d: Addr: 0x%x, name: %s" % (idx, kthread_ptr, name)
            kthread_ptr = kthread_ptr["next"]
            idx += 1
        result = ("Found a Linked List with %d kthread:" % idx) + result
        return result

    def complete(self, text, word):
        # We expect the argument passed to be a symbol so fallback to the
        # internal tab-completion handler for symbols
        return gdb.COMPLETE_SYMBOL

    def invoke(self, args, from_tty):
        # We can pass args here and use Python CLI utilities like argparse
        # to do argument parsing
        print("Args Passed: %s" % args)

        kthread_ptr_val = gdb.parse_and_eval(args)
        if str(kthread_ptr_val.type) != "struct kthread *":
            print("Expected pointer argument of type (struct kthread *)")
            return

        print(self._kthread_list_to_str(kthread_ptr_val))

KthreadListDumpCmd()