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Programmable debugger
d4cc7945af
At Facebook, we link OpenMP code with libomp instead of libgomp. We have an internal patch to drgn to do this, as it can't be done by setting CFLAGS/LDFLAGS. Let's add a way to specify the OpenMP library at configure time so that we can drop the internal patch. |
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docs | ||
drgn | ||
examples/linux | ||
libdrgn | ||
scripts | ||
tests | ||
.git-blame-ignore-revs | ||
.gitignore | ||
.readthedocs.yml | ||
.travis.yml | ||
COPYING | ||
MANIFEST.in | ||
README.rst | ||
setup.py |
drgn ==== .. image:: https://img.shields.io/pypi/v/drgn :target: https://pypi.org/project/drgn/ :alt: PyPI .. image:: https://travis-ci.org/osandov/drgn.svg?branch=master :target: https://travis-ci.org/osandov/drgn :alt: Build Status .. image:: https://readthedocs.org/projects/drgn/badge/?version=latest :target: https://drgn.readthedocs.io/en/latest/?badge=latest :alt: Documentation Status .. image:: https://img.shields.io/badge/code%20style-black-000000.svg :target: https://github.com/psf/black .. start-introduction 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: .. code-block:: pycon >>> 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 <https://www.gnu.org/software/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 for more purpose-built tools. drgn was developed for debugging the Linux kernel (as an alternative to the `crash <http://people.redhat.com/anderson/>`_ utility), but it can also debug userspace programs written in C. C++ support is planned. .. end-introduction Documentation can be found at `drgn.readthedocs.io <https://drgn.readthedocs.io>`_. Installation ------------ .. start-install-dependencies 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 <https://github.com/ptesarik/libkdumpfile>`_ if you want support for kdump-compressed kernel core dumps .. end-install-dependencies Then, run: .. code-block:: console $ sudo pip3 install drgn See the `installation documentation <https://drgn.readthedocs.io/en/latest/installation.html>`_ for more options. Quick Start ----------- .. start-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: .. code-block:: pycon $ 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 .. end-quick-start See the `user guide <https://drgn.readthedocs.io/en/latest/user_guide.html>`_ for more information. License ------- .. start-license Copyright 2018-2020 Omar Sandoval drgn is licensed under the `GPLv3 <https://www.gnu.org/licenses/gpl-3.0.en.html>`_ or later. .. end-license