Getting error while running examples about angr-utils

[axt]

Hi!

The dot utility is needed to convert the graphs from the raw dot format, to anything else, like pdf, svg, png, etc. The format can be specified as a parameter to plot_cfg, the default setting is png.

You can do two things:

• The dotutility is provided by graphviz, if you install graphviz the problem should disappear.
• Specify a format="raw"parameter to plot_cfg: in this case the output will be the graph in the raw dot format. Still if you want to view that, you will need graphviz to render it, so I recommend to install graphviz.

[it-nerdy]

format="raw" parameter works fine. I am able to see raw files. I installed graphviz but still error persists, in case of format="png". May be i will use other ways to convert raw file to visible image file.

[axt]

With the dot utility you can use the following command, to convert the raw files into a png:

dot -Tpng -o out.png in.raw

you should check, if this is working for you. If it does, then the error lays somewhere in the pydot package, I use that to interact with dot. My guess is that somehow the dot utility is not found by the package, or it is not executable, or something like that.

I usually generate raw files (because its much faster), and view them with xdot, which also uses the dot command for rendering. (https://github.com/jrfonseca/xdot.py)

Environment issues are hard to debug, I would do an

strace -f python script_to_generate_the_graph.py |& grep 'dot' 

to see what happens under the hood.

[it-nerdy]

Thanks for you quick responses, it helped me in resolving the issue. I got the point, actually pydot is invoking a command that uses dot utility (it is running internally dot -Tpng -o out.png in.raw ) . Since I don't have xdot installed in my system it is was throwing error. Now, I installed xdot tool in my linux system, issue is resolved. I can generate png files directly. May be, you can document it some where, in requirements to install xdot. Thanks again.

[axt]

I think I figured out what happened.

The xdot package is not needed for the library to function correctly, but the xdot package has
graphviz as a dependency, so when you installed xdot you also installed graphviz.

My guess is, that when you tried to install graphviz before, instead of the system package graphviz which is the graph rendering tool, you installed the python package called graphviz, which is just a python wrapper around the utility.

$ apt-file find -F '/usr/bin/dot'
graphviz: /usr/bin/dot

$ apt-file show xdot
xdot: /usr/bin/xdot
xdot: /usr/lib/python3/dist-packages/xdot-0.7.egg-info/PKG-INFO
xdot: /usr/lib/python3/dist-packages/xdot-0.7.egg-info/dependency_links.txt
xdot: /usr/lib/python3/dist-packages/xdot-0.7.egg-info/entry_points.txt
xdot: /usr/lib/python3/dist-packages/xdot-0.7.egg-info/top_level.txt
xdot: /usr/lib/python3/dist-packages/xdot.py
xdot: /usr/share/applications/xdot.desktop
xdot: /usr/share/doc/xdot/changelog.Debian.gz
xdot: /usr/share/doc/xdot/copyright
xdot: /usr/share/man/man1/xdot.1.gz