Skip to main content

drgn

PyPI Build Status Documentation Status https://img.shields.io/badge/code%20style-black-000000.svg

drgn (pronounced “dragon”) is a debugger with an emphasis on programmability. drgn exposes the types and variables in a program for easy, expressive scripting in Python. For example, you can debug the Linux kernel:

>>> from drgn.helpers.linux import list_for_each_entry
>>> for mod in list_for_each_entry('struct module',
...                                prog['modules'].address_of_(),
...                                'list'):
...    if mod.refcnt.counter > 10:
...        print(mod.name)
...
(char [56])"snd"
(char [56])"evdev"
(char [56])"i915"

Although other debuggers like GDB have scripting support, drgn aims to make scripting as natural as possible so that debugging feels like coding. This makes it well-suited for introspecting the complex, inter-connected state in large programs. It is also designed as a library that can be used to build debugging and introspection tools; see the official tools.

drgn was developed for debugging the Linux kernel (as an alternative to the crash utility), but it can also debug userspace programs written in C. C++ support is in progress.

Documentation can be found at drgn.readthedocs.io.

Installation

Install dependencies:

Arch Linux:

$ sudo pacman -S --needed autoconf automake bison bzip2 flex gawk gcc libtool make pkgconf python python-setuptools xz zlib

Debian/Ubuntu:

$ sudo apt-get install autoconf automake bison flex gawk gcc libbz2-dev liblzma-dev libtool make pkgconf python3 python3-dev python3-setuptools zlib1g-dev

Note that Debian Stretch, Ubuntu Trusty, and Ubuntu Xenial (and older) ship Python versions which are too old. Python 3.6 or newer must be installed manually.

Fedora:

$ sudo dnf install autoconf automake bison bzip2-devel flex gawk gcc libtool make pkgconf python3 python3-devel python3-setuptools xz-devel zlib-devel

Optionally, install:

  • libkdumpfile if you want support for kdump-compressed kernel core dumps

Then, run:

$ sudo pip3 install drgn

See the installation documentation for more options.

Quick Start

drgn debugs the running kernel by default; run sudo drgn. To debug a running program, run sudo drgn -p $PID. To debug a core dump (either a kernel vmcore or a userspace core dump), run drgn -c $PATH. The program must have debugging symbols available.

Then, you can access variables in the program with prog['name'], access structure members with ., use various predefined helpers, and more:

$ sudo drgn
>>> prog['init_task'].comm
(char [16])"swapper/0"
>>> d_path(fget(find_task(prog, 1), 0).f_path.address_of_())
b'/dev/null'
>>> max(task.stime for task in for_each_task(prog))
(u64)4192109975952
>>> sum(disk.gendisk.part0.nr_sects for disk in for_each_disk(prog))
(sector_t)999705952

See the user guide for more information.

License

Copyright (c) Facebook, Inc. and its affiliates.

drgn is licensed under the GPLv3 or later.

Metadata

Release files for drgn 0.0.7

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for drgn 0.0.7
File Size Uploaded
drgn-0.0.7.tar.gz 9.3 MB Details

Release files / drgn-0.0.7.tar.gz

Download URL drgn-0.0.7.tar.gz
Size 9.3 MB
Tags Source
SHA-256 checksum
How to use checksums
c0b20b0e2ea4033eb1533664c6c469b1f975db8cd04e9e3df14630b212e15d1e
BLAKE2b-256 checksum
How to use checksums
ffd07cc3c4a8e2ffcf956e228633a20d7db0034ca153c74d3520aa3ada9b01fe
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/2.0.0 pkginfo/1.5.0.1 requests/2.24.0 setuptools/49.2.0 requests-toolbelt/0.9.1 tqdm/4.48.0 CPython/3.8.4
Anthropic, PBC Visionary sponsor Bloomberg Visionary sponsor Hudson River Trading Visionary sponsor Meta Visionary sponsor NVIDIA Visionary sponsor Microsoft Sustainability sponsor Depot Continuous Integration AWS Cloud computing and Security Sponsor Datadog Monitoring Fastly CDN Google Download Analytics Sentry Error logging StatusPage Status page