Dev_Python

Developing plugins in Python

Light plugins

Light plugins are smaller faster-to-run plugins which is utilizing the VmmPy API.

Light plugins are easy-to-construct and print its output to stdout (with Python print() function). They show up in sub-directories of the /py/ root directory. They may be constructed on a global basis or per-user basis, not on a per-process basis.

It's important that light plugins are fairly quick to render and that output isn't too large since it will be cached in-memory.

Light plugins are placed in the plugin directory and should be named according to the following convention: pyp_<ignored>_<root|user>_<subdir>_<filename>.py where:

• <ignored> is ignored.
• <root|user> should be either of root (standard global plugin) or user (by-user plugin). NB! it's not possible to have per-process light plugins.
• <subdir> is the sub-directory, for nested sub-directories use $ i.e. dir1$dir2 -> dir1/dir2.
• <filename> is the file name without the standard .txt file extension.

Examples of light plugins may be found in the MemProcFS plugins directory.

Standard plugins

This section relates to integration python plugin functionality in MemProcFS - for including MemProcFS in stand alone applications and scripts please check out the Python API section.

Python plugin functionality requires that MemProcFS is able to access a Python 3.6 (or later) installation - either an embedded Python in the python sub-directory or on the system path.

Creating a minimal plugin is as simple as dropping a python module called pym_* in the plugins directory. Please see the example Python plugin/module pym_procstruct for how to do this.

The Python plugin module should make the Initialize and Close functions available in its init.py file - like in the example below:

init.py:

from plugins.pym_testmodule.pym_testmodule import (
    Initialize,
    Close,
)
__all__ = [
    "Initialize",
    "Close",
]

pym_testmodule.py:

from vmmpy import *
from vmmpycc import *

def Callback_List(pid, path):
    # not part of example - please see pym_procstruct.py for example info.
    pass

def Callback_Read(pid, path, bytes_length, bytes_offset):
    # not part of example - please see pym_procstruct.py for example info.
    pass

def Callback_Write(pid, path, bytes_data, bytes_offset):
    # not part of example - please see pym_procstruct.py for example info.
    pass

def Close():
    # not part of example - please see pym_procstruct.py for example info.
    pass

def Initialize(target_system, target_memorymodel):
    # Check that the operating system is 32-bit or 64-bit Windows. If it's not
    # then raise an exception to terminate loading of this module.
    if target_system != VMMPY_SYSTEM_WINDOWS_X64 and target_system != VMMPY_SYSTEM_WINDOWS_X86:
        raise RuntimeError("Only Windows is supported by the pym_procstruct module.")
    # Register a directory with the VmmPyPlugin plugin manager. The directory
    # is a non-root (i.e. a process) directory and have a custom List function.
    VmmPyPlugin_FileRegisterDirectory(False, 'procstruct', Callback_List)
    # alternatively: register a file (in or not in a sub-directory to /py/) with the
    # python plugin manager. Necessary sub-directories will be created if required.
    VmmPyPlugin_FileRegister(False, 'testdir/testfile.txt', 4096, Callback_Read, Callback_Write)