# This file is Copyright 2019 Volatility Foundation and licensed under the Volatility Software License 1.0
# which is available at https://www.volatilityfoundation.org/license/vsl-v1.0
#

import logging
from typing import Callable, List, Generator, Iterable, Type, Optional

from volatility3.framework import renderers, interfaces, exceptions
from volatility3.framework.configuration import requirements
from volatility3.framework.objects import utility
from volatility3.framework.renderers import format_hints
from volatility3.plugins.windows import pslist

vollog = logging.getLogger(__name__)

# these are from WinNT.h
winnt_protections = {
    "PAGE_NOACCESS": 0x01,
    "PAGE_READONLY": 0x02,
    "PAGE_READWRITE": 0x04,
    "PAGE_WRITECOPY": 0x08,
    "PAGE_EXECUTE": 0x10,
    "PAGE_EXECUTE_READ": 0x20,
    "PAGE_EXECUTE_READWRITE": 0x40,
    "PAGE_EXECUTE_WRITECOPY": 0x80,
    "PAGE_GUARD": 0x100,
    "PAGE_NOCACHE": 0x200,
    "PAGE_WRITECOMBINE": 0x400,
    "PAGE_TARGETS_INVALID": 0x40000000,
}


class VadInfo(interfaces.plugins.PluginInterface):
    """Lists process memory ranges."""

    _required_framework_version = (2, 0, 0)
    _version = (2, 0, 0)
    MAXSIZE_DEFAULT = 1024 * 1024 * 1024  # 1 Gb

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._protect_values = None

    @classmethod
    def get_requirements(cls) -> List[interfaces.configuration.RequirementInterface]:
        # Since we're calling the plugin, make sure we have the plugin's requirements
        return [requirements.ModuleRequirement(name = 'kernel', description = 'Windows kernel',
                                                         architectures = ["Intel32", "Intel64"]),
                # TODO: Convert this to a ListRequirement so that people can filter on sets of ranges
                requirements.IntRequirement(name = 'address',
                                            description = "Process virtual memory address to include " \
                                                          "(all other address ranges are excluded). This must be " \
                                                          "a base address, not an address within the desired range.",
                                            optional = True),
                requirements.ListRequirement(name = 'pid',
                                             description = 'Filter on specific process IDs',
                                             element_type = int,
                                             optional = True),
                requirements.PluginRequirement(name = 'pslist', plugin = pslist.PsList, version = (2, 0, 0)),
                requirements.BooleanRequirement(name = 'dump',
                                                description = "Extract listed memory ranges",
                                                default = False,
                                                optional = True),
                requirements.IntRequirement(name = 'maxsize',
                                            description = "Maximum size for dumped VAD sections " \
                                                          "(all the bigger sections will be ignored)",
                                            default = cls.MAXSIZE_DEFAULT,
                                            optional = True),
                ]

    @classmethod
    def protect_values(cls, context: interfaces.context.ContextInterface, layer_name: str,
                       symbol_table: str) -> Iterable[int]:
        """Look up the array of memory protection constants from the memory
        sample. These don't change often, but if they do in the future, then
        finding them dynamically versus hard-coding here will ensure we parse
        them properly.

        Args:
            context: The context to retrieve required elements (layers, symbol tables) from
            layer_name: The name of the layer on which to operate
            symbol_table: The name of the table containing the kernel symbols
        """

        kvo = context.layers[layer_name].config["kernel_virtual_offset"]
        ntkrnlmp = context.module(symbol_table, layer_name = layer_name, offset = kvo)
        addr = ntkrnlmp.get_symbol("MmProtectToValue").address
        values = ntkrnlmp.object(object_type = "array", offset = addr, subtype = ntkrnlmp.get_type("int"), count = 32)
        return values  # type: ignore

    @classmethod
    def list_vads(cls, proc: interfaces.objects.ObjectInterface,
                  filter_func: Callable[[interfaces.objects.ObjectInterface], bool] = lambda _: False) -> \
            Generator[interfaces.objects.ObjectInterface, None, None]:
        """Lists the Virtual Address Descriptors of a specific process.

        Args:
            proc: _EPROCESS object from which to list the VADs
            filter_func: Function to take a virtual address descriptor value and return True if it should be filtered out

        Returns:
            A list of virtual address descriptors based on the process and filtered based on the filter function
        """
        for vad in proc.get_vad_root().traverse():
            if not filter_func(vad):
                yield vad

    @classmethod
    def vad_dump(cls,
                 context: interfaces.context.ContextInterface,
                 proc: interfaces.objects.ObjectInterface,
                 vad: interfaces.objects.ObjectInterface,
                 open_method: Type[interfaces.plugins.FileHandlerInterface],
                 maxsize: int = MAXSIZE_DEFAULT) -> Optional[interfaces.plugins.FileHandlerInterface]:
        """Extracts the complete data for Vad as a FileInterface.

        Args:
            context: The context to retrieve required elements (layers, symbol tables) from
            proc: an _EPROCESS instance
            vad: The suspected VAD to extract (ObjectInterface)
            open_method: class to provide context manager for opening the file
            maxsize: Max size of VAD section (default MAXSIZE_DEFAULT)

        Returns:
            An open FileInterface object containing the complete data for the process or None in the case of failure
        """

        try:
            vad_start = vad.get_start()
            vad_end = vad.get_end()
        except AttributeError:
            vollog.debug("Unable to find the starting/ending VPN member")
            return None

        if maxsize > 0 and (vad_end - vad_start) > maxsize:
            vollog.debug(f"Skip VAD dump {vad_start:#x}-{vad_end:#x} due to maxsize limit")
            return None

        proc_id = "Unknown"
        try:
            proc_id = proc.UniqueProcessId
            proc_layer_name = proc.add_process_layer()
        except exceptions.InvalidAddressException as excp:
            vollog.debug("Process {}: invalid address {} in layer {}".format(proc_id, excp.invalid_address,
                                                                             excp.layer_name))
            return None

        proc_layer = context.layers[proc_layer_name]
        file_name = f"pid.{proc_id}.vad.{vad_start:#x}-{vad_end:#x}.dmp"
        try:
            file_handle = open_method(file_name)
            chunk_size = 1024 * 1024 * 10
            offset = vad_start
            while offset < vad_end:
                to_read = min(chunk_size, vad_end - offset)
                data = proc_layer.read(offset, to_read, pad = True)
                if not data:
                    break
                file_handle.write(data)
                offset += to_read

        except Exception as excp:
            vollog.debug(f"Unable to dump VAD {file_name}: {excp}")
            return None

        return file_handle

    def _generator(self, procs):
        kernel = self.context.modules[self.config['kernel']]

        def passthrough(_: interfaces.objects.ObjectInterface) -> bool:
            return False

        filter_func = passthrough
        if self.config.get('address', None) is not None:

            def filter_function(x: interfaces.objects.ObjectInterface) -> bool:
                return x.get_start() not in [self.config['address']]

            filter_func = filter_function

        for proc in procs:
            process_name = utility.array_to_string(proc.ImageFileName)

            for vad in self.list_vads(proc, filter_func = filter_func):

                file_output = "Disabled"
                if self.config['dump']:
                    file_handle = self.vad_dump(self.context, proc, vad, self.open, self.config['maxsize'])
                    file_output = "Error outputting file"
                    if file_handle:
                        file_handle.close()
                        file_output = file_handle.preferred_filename

                yield (0, (proc.UniqueProcessId, process_name, format_hints.Hex(vad.vol.offset),
                           format_hints.Hex(vad.get_start()), format_hints.Hex(vad.get_end()), vad.get_tag(),
                           vad.get_protection(
                               self.protect_values(self.context, kernel.layer_name, kernel.symbol_table_name),
                               winnt_protections), vad.get_commit_charge(), vad.get_private_memory(),
                           format_hints.Hex(vad.get_parent()), vad.get_file_name(), file_output))

    def run(self):
        kernel = self.context.modules[self.config['kernel']]

        filter_func = pslist.PsList.create_pid_filter(self.config.get('pid', None))

        return renderers.TreeGrid([("PID", int), ("Process", str), ("Offset", format_hints.Hex),
                                   ("Start VPN", format_hints.Hex), ("End VPN", format_hints.Hex), ("Tag", str),
                                   ("Protection", str), ("CommitCharge", int), ("PrivateMemory", int),
                                   ("Parent", format_hints.Hex), ("File", str), ("File output", str)],
                                  self._generator(
                                      pslist.PsList.list_processes(context = self.context,
                                                                   layer_name = kernel.layer_name,
                                                                   symbol_table = kernel.symbol_table_name,
                                                                   filter_func = filter_func)))
