# This file was contributed to the Volatility Framework Version 3.
# Copyright (C) 2018 Volatility Foundation.
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from typing import Callable, Iterable, List

import volatility.framework.interfaces.plugins as interfaces_plugins
from volatility.framework import renderers, interfaces, contexts
from volatility.framework.automagic import linux
from volatility.framework.configuration import requirements
from volatility.framework.objects import utility


class PsList(interfaces_plugins.PluginInterface):
    """Lists the processes present in a particular linux memory image"""

    @classmethod
    def get_requirements(cls) -> List[interfaces.configuration.RequirementInterface]:
        return [
            requirements.TranslationLayerRequirement(
                name = 'primary', description = 'Memory layer for the kernel', architectures = ["Intel32", "Intel64"]),
            requirements.SymbolTableRequirement(name = "vmlinux", description = "Linux kernel symbols")
        ]

    @classmethod
    def create_pid_filter(cls, pid_list: List[int] = None) -> Callable[[int], bool]:
        # FIXME: mypy #4973 or #2608
        pid_list = pid_list or []
        filter_list = [x for x in pid_list if x is not None]
        if filter_list:

            def filter_func(x):
                return x.pid not in filter_list

            return filter_func
        else:
            return lambda _: False

    def _generator(self):
        for task in self.list_tasks(
                self.context,
                self.config['primary'],
                self.config['vmlinux'],
                filter_func = self.create_pid_filter([self.config.get('pid', None)])):
            pid = task.pid
            ppid = 0
            if task.parent:
                ppid = task.parent.pid
            name = utility.array_to_string(task.comm)
            yield (0, (pid, ppid, name))

    @classmethod
    def list_tasks(cls,
                   context: interfaces.context.ContextInterface,
                   layer_name: str,
                   vmlinux_symbols: str,
                   filter_func: Callable[[int], bool] = lambda _: False
                   ) -> Iterable[interfaces.objects.ObjectInterface]:
        """Lists all the tasks in the primary layer"""
        linux.LinuxUtilities.aslr_mask_symbol_table(context, vmlinux_symbols, layer_name)

        vmlinux = contexts.Module(context, vmlinux_symbols, layer_name, 0, absolute_symbol_addresses = True)

        init_task = vmlinux.object(symbol_name = "init_task")

        for task in init_task.tasks:
            if not filter_func(task):
                yield task

    def run(self):
        return renderers.TreeGrid([("PID", int), ("PPID", int), ("COMM", str)], self._generator())