Reverse Architecting using Relation Algebra.pdf
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This document discusses reverse architecting software by extracting relationships from source code using relation algebra. It describes extracting relations from code without compiling or linking, storing them in a database, and applying relation algebra operations like join and inverse to abstract the relations. The abstracted relations can then be visualized as graphs or tables to understand aspects of the software architecture like inter-task communication and message queue usage. Reverse architecting is challenging but relation algebra can help reformulate many analysis questions and filter irrelevant data to meet analysis goals.
Reverse Architecting using Relation Algebra.pdf
- 1. Dharma Ganesan Reverse Architecting using Relation Algebra
- 2. 2 What’s On The Agenda ● Software Architecture ● Reverse Architecting ● A little bit math - I promise ● Extract-Abstract-Present to Reverse Architecting ● Demos (during the presentation) ● Some References
- 3. 3 Software Architecture ● Software architecture deals with the design of the high-level structure of the software ● Assembly of architectural elements in some well-chosen forms to satisfy requirements ● (including Reliability, Scalability, Portability, etc) ● Software architecture deals with ● abstraction ● decomposition and composition ● styles (pipe-and-filter, publish-subscribe, etc.)
- 4. 4 Describing Software Architecture using Views ● How to best describe Software Architecture is a topic of on-going R&D ● In literature, views are used to describe Software Architecture ● Each view address one concern, for example: ● Structural view shows the decomposition of system ● Behavioral view shows how components interact at run-time ● Deployment view shows how components are assigned to hardware elements
- 5. 5 Reverse Architecting Informally, extracting architecture information from source code (including makefiles, docs, test cases, etc.) Some challenges: ● Software architecture is an invisible one ● It is difficult to “see” architecture in source code ● Real-world systems have a lot of code Goal of reverse architecting: Semi-automatically extract architecture from source code
- 6. 6 Some questions we ask ● What are the entry-points to the system? ● Which classes inherit from this class? ● Which files deal with network communication? ● Is this function reachable from ‘main’? ● Are there missing code not in repo? ● Which functions are dead? ● etc. etc. etc. All these questions can be be viewed as relational algebra questions!
- 7. 7 Just a bit of math (I promise) What do we mean by Relation Algebra? Three things: Set - an unordered collection E.g., set of files {f1.c, f2.c, …} Binary Relation - an unordered set of pairs E.g., {<main, run>, <run, execute>, …, } Multi-Relation - Weighted Binary Relation E.g., {<caller, callee, 5>, …}
- 8. 8 Relation Algebra Queries They are made of set-theory operators only For example, union, intersection, complement, etc. Compose two relations using join (a.k.a., comp) part_of= {<a A}, <b B>, <c C>} call = {<a b>, <b, c>} E.g: inverse(part_of) comp (call) comp (part_of)?
- 9. 9 Relation Algebra Toolset Made of small utilities for each set-theory operator Combine utilities using pipe-and-filter style rel_inv part_of | rel_comp call - | rel_comp - part_of I personally used RA tools for several reverse architecting projects My Phd thesis has more details
- 10. 10 A Reverse Architecting Approach (Philips in 1990s) Extraction: semi-automated extraction of different relations (import, inherit, call, etc.) Abstraction: rise the level of abstraction using relational algebra queries (imagine SQL) Presentation: visualize using graphs, tables, etc. (These were published by Philips)
- 11. 11 Extraction ● Language-specific parsers to extract different relations: inherit, call, include, etc. ○ Code need not compile or link ● Each relation is stored in database/files ● Depending on the goal, more custom parsers have to be developed to extract code relations ● For example, if your goal is to extract inter-task RPC views, you need to ○ extract tasks, queue names, which function writes to or read from queues, etc.
- 12. 12 Abstraction A suite of relation algebra operators was developed for abstraction (see demos) Again, depending on the goal one could apply different abstraction operators Some common abstraction (examples): ● Lift class-level dependencies to package-level ● Filter out irrelevant information for your goal ○ For example, show all Java packages that depend on Crypto packages ● Abstraction of runtime structure to show inter-task communication (more details later)
- 13. 13 Some examples: Folder-level dependency from code relations
- 14. 14 A medical device case study Goal: Extract architecture from source code Visualize inter-task and msg queue communication Approach: Extract relations from code Abstraction using Relation Algebra Visualize using our graph visualization tools
- 15. 15 Extracted relations/sets Our parser extracts names of tasks, queues, semaphores, etc by pattern matching of library calls
- 16. 16 Abstraction We write SQL-like queries using join, inverse, and other operations on the extracted relations Output is also relations/sets
- 17. 17 Presentation We visualize relations as graphs or tables in general For inter-task structure, we have something like this from abstracted relations:
- 18. 18 Conclusion/Takeaways ● Reverse architecting is a challenging problem ● Extract-Abstract-Present using relational algebra can help with reverse architecting ● Many of the analysis questions can be reformulated as relational algebra questions! ● The key is to have a goal for your reverse architecting effort - to filter out irrelevant data
- 19. 19 Some Reverse Engineering Papers (not complete at all) https://www.win.tue.nl/~wstomv/edu/2ii45/yea r-0910/Maintaining_a_Legacy.pdf https://www.cs.cmu.edu/~aldrich/courses/654-s p05/ReengineeringTaxonomy.pdf https://ieeexplore.ieee.org/document/5959691 https://ieeexplore.ieee.org/document/5071104 …