drgn
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 0.0.8
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| drgn-0.0.8.tar.gz | 9.3 MB | Details |
Release files / drgn-0.0.8.tar.gz
| Download URL | drgn-0.0.8.tar.gz |
|---|---|
| Size | 9.3 MB |
| Tags | Source |
|
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twine/3.2.0 pkginfo/1.6.1 requests/2.24.0 setuptools/50.3.2 requests-toolbelt/0.9.1 tqdm/4.51.0 CPython/3.8.6
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