DSIsrc

This project contains the DSIsrc front-end component and its DSIcore algorithm implementation. The front end uses CIL [1] to instrument the source code by inserting instructions for recording pointer writes and memory (de-)allocations. A trace is generated upon executing the instrumented source file. This trace is then further evaluated by DSIcore wrt. to the observed data structures and their relationships [2].

Installation

The following installation procedure requires an installation of Ubuntu 14.04.5 LTS (Trusty Tahr) and shows how to install the required dependencies, setup the environment, and run DSIsrc on a test program.

Software Dependency Installation

1. Install git:
   $ sudo apt-get install git

2. Install the Java 7 Runtime Environment:
   $ sudo apt-get install openjdk-7-jre

3. Install the Java 7 Software Development Kit:
   $ sudo apt-get install openjdk-7-jdk

4. Note: This step is optional, in the sense that DSIsrc can be run without executing the instructions below on the existing examples. In order to apply DSIsrc to new examples, the C Intermediate Language (CIL) is required for instrumenting the source files. The following steps guide through the installation and setup of CIL for DSI:

5. Install the required dependencies:
   $ apt-get install ocaml ocaml-findlib

6. Download CIL (version 1.7.3) from their GitHub page and extract the archive:
   wget https://github.com/cil-project/cil/archive/cil-1.7.3.zip

7. Setup a new symlink in the src/ext folder of CIL called instrument.ml, which points to path/to/DSIsrc/resources/cil-inst/instrument.ml:
   ln -s path/to/DSIsrc/resources/cil-inst/instrument.ml /path/to/CIL/src/ext

8. Add Instrument.feature; to let features : C.featureDescr list = ... in file /path/to/CIL/src/main.ml:

let features : C.featureDescr list = 
[ Epicenter.feature;
....
Instrument.feature;
] 
@ Feature_config.features 

5. Configure and compile CIL by running the following commands within CIL's root directory:
   $ ./configure
$ make
$ make test

6. Export the path to the cilly script, which is located at /path/to/CIL/bin/cilly, under the environment name CILLY_BIN; this environment variable is used by the makefiles in the test program folder of DSIsrc:
   CILLY_BIN=/path/to/CIL/bin/cilly; export CILLY_BIN

7. Create a new directory for the DSI toolchain and navigate inside:
   $ mkdir DSI-complete
$ cd DSI-complete

8. Clone the DSIsrc and DSI-logger GIT repositories:
   $ git clone https://github.com/uniba-swt/DSIsrc.git
$ git clone https://github.com/uniba-swt/DSIlogger.git

9. Download Eclipse for Scala (version 3.0.4):
   $ wget http://downloads.typesafe.com/scalaide-pack/3.0.4.vfinal-211-20140421/scala-SDK-3.0.4-2.11-2.11-linux.gtk.x86_64.tar.gz

10. Extract the Eclipse folder from the archive and remove the archive:
    $ tar -xf scala-SDK-3.0.4-2.11-2.11-linux.gtk.x86_64.tar.gz; rm scala-SDK-3.0.4-2.11-2.11-linux.gtk.x86_64.tar.gz

11. Run Eclipse, either from the file explorer or via a terminal:
    $ ./eclipse/eclipse

Setting up the environment

Run Eclipse and import the projects DSIsrc and DSIlogger via the Eclipse import dialogue Project > Import > General > Existing Projects into Workspace. Each required library should be listed in the Build Path, and the Project References should already have been established.

Running an example using DSIsrc

To run an example, use Eclipse and the provided launch configurations located in /path/to/DSIsrc/resources/eclipse-run-configurations. Install CIL as described above in order to run user provided examples from scratch, and consult the makefiles from the supplied examples to create a proper makefile target. Note that the source file containing the example program must be instrumented, compiled, and executed using CIL. Upon running the instrumented executable, the types.xml and trace.xml are created.

Sample command line parameters of test program mbg-dll-with-dll-children:

--xml:resources/test-programs/mbg-dll-with-dll-children/trace.xml  
--typexml:resources/test-programs/mbg-dll-with-dll-children/types.xml
--xsd:resources/xml/trace-schema.xsd  
--featuretracexsd:resources/xml/feature-trace-schema.xsd

In order to adjust this example to a user's needs, point xml and typexml to the appropriate trace and type files. The xsd and featuretracexsd remain the same.

Files used/produced by DSI

All test programs are located in the folder resources/test-programs relative to the DSIbin root directory. Each test case folder comprises the following files:

DSIsrc

Filename	Description
C source code	The source code of the test program, often named as the folder in which it resides.
Makefile	Used to compile the source files and generate an executable.
types.xml	Stores type information about the executable.
trace.xml	Contains a sequence of events obtained from running an instrumented executable.

To ease using Eclipse for running examples, each test program has its own launch configuration file stored in resources/eclipse-run-configurations.

DSIbin

Filename	Description
<example>.c	The source file of the binary example.
<example>.taint	The heap types as excavated by Howard. Each type is identified by its callstack using an MD5 checksum that is found in <example>.callstack.
<example>.callstack	The list of callstacks detected in the binary as reported by Howard. Each callstack is identified by its MD5 checksum that is used in the <example>.taint.
<example>.mergeinfo	The list of Howard's merged callstacks identified by their MD5 checksum.
<example>.stack	The list of stackframes identified by their function address as excavated by Howard.
<example>.stdout-call	Log files used during the development phase.
<example>.stdout-return	Log files used during the development phase.
<example>.stdout	Contains the shell output.
<example>.objdump	Contains the objdump of the binary file for manual inspection by the user; this dump is not used by DSI.
<example>.s	Assembly file obtained from gcc for manual inspection by the user; this dump is not used by DSI.
types.xml	Contain the type information of the binary executable.
trace.xml	Contains a sequence of events obtained from running the instrumented binary.

On the binary code level (DSIbin), the rich type information compared to source code/byte code is missing. The type inference tool Howard is used to excavate type information in a given binary. Moreover, Intel's Pin framework is employed to retrieve a trace of the program execution. This information is aggregated by DSIbin and used to further improve the type information inferred by Howard. Each test case in the repository contains the files generated by Howard such that DSIbin can be run on each example, even though Howard is not publicly available.

Data produced by running DSI

If logging is enabled in the source code, DSIsrc/bin will generate the following output for a given test case. By default, only the final result will be written to disk (log/agg).

Folder	Description
log/*	Contains one points-to-graph for each event.
log/mbg	Contains the strand graphs annotated with data structure labels and evidences.
log/mmbg	Contains the folded strand graphs annotated with data structure labels and evidences representing the structural repetition.
log/agg	Contains the final result for each entry pointer, i.e., the aggregated strand graph with the highest ranked label on top.

In case of DSIbin, the type hypotheses can be found in the dsi-refined-types folder, e.g., dsi-refined-types/logtypes_<id>/*, which comprises the same structure as described above.

Filename	Description
types_<id>.mergeinfo	Refined mergeinfo inferred by DSIref.
types_<id>.msrprf	Performance measurement obtained from usr/bin/time.
types_<id>.stack	Refined stack types inferred by DSiref.
types_<id>.taint	Refined heap types inferred by DSiref.
types_<id>trace.xml	The trace generated by DSIref, which contains the refined types used by DSI.
types_<id>types.xml	The type information produced by DSIref and used by DSI.

An aggregated strand graph is generated for each entry pointer and encoded as a dot file. In most cases, the aggregated strand graph for the longest running entry pointer is of interest, which can be found and opened with the command $ rm graph_[^c]*;grep aggCnt * | sed -e 's/^.*ep: //' -e 's/ start.*aggCnt: /,/' -e 's/<.*//' | sort -t, -nk2 | tail -n 1 | sed -e s'/\([0-9]\+\).*/*x_\1.dot/'| xargs find . -name | xargs xdot.

References

1. CIL - The C Intermediate Language
2. DSI: An evidence-based approach to identify dynamic data structures in C programs