DOCSLIB.ORG

Virtual Separation of Concerns: Toward Preprocessors 2.0

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Virtual Separation of Concerns: Toward Preprocessors 2.0 Virtual Separation of Concerns: Toward Preprocessors 2.0 Dissertation zur Erlangung des akademischen Grades Doktoringenieur (Dr.-Ing.) angenommen durch die Fakultät für Informatik der Otto-von-Guericke-Universität Magdeburg von Dipl.-Wirt.-Inform. Christian Kästner geb. am 21. September 1982 in Schwedt/Oder Gutachter: Prof. Dr. Gunter Saake Prof. Don Batory, Ph.D. Prof. Krzysztof Czarnecki, Ph.D. Promotionskolloquium: Magdeburg, den 31. Mai 2010 Kästner, Christian: Virtual Separation of Concerns: Toward Preprocessors 2.0 Dissertation, Otto-von-Guericke-Universität Magdeburg, 2010. Abstract Conditional compilation with preprocessors such as cpp is a simple but effective means to implement variability. By annotating code fragments with #ifdef and #endif directives, different program variants with or without these annotated frag- ments can be created, which can be used (among others) to implement software product lines. Although, such annotation-based approaches are frequently used in practice, researchers often criticize them for their negative effect on code quality and maintainability. In contrast to modularized implementations such as compo- nents or aspects, annotation-based implementations typically neglect separation of concerns, can entirely obfuscate the source code, and are prone to introduce subtle errors. Our goal is to rehabilitate annotation-based approaches by showing how tool support can address these problems. With views, we emulate modularity; with a visual representation of annotations, we reduce source code obfuscation and in- crease program comprehension; and with disciplined annotations and a product- line–aware type system, we prevent or detect syntax and type errors in the entire software product line. At the same time we emphasize unique benefits of annota- tions, including simplicity, expressiveness, and being language independent. All in all, we provide tool-based separation of concerns without necessarily dividing source code into physically separated modules; we name this approach virtual separation of concerns. We argue that with these improvements over contemporary preprocessors, vir- tual separation of concerns can compete with modularized implementation mech- anisms. Despite our focus on annotation-based approaches, we do intend not give a definite answer on how to implement software product lines. Modular implementations and annotation-based implementations both have their advan- tages; we even present an integration and migration path between them. Our goal is to rehabilitate preprocessors and show that they are not a lost cause as many researchers think. On the contrary, we argue that – with the presented improve- ments – annotation-based approaches are a serious alternative for product-line implementation. iii Acknowledgments Finishing this dissertation would have been impossible without the help of many persons. First and foremost, I would like to thank Sven Apel with whom I worked together closely for the last three years. Sven supported me since my Master’s thesis and guided my research in many ways. Despite communicating mostly via email and telephone due to different locations, our collaborations were reliable, efficient, and productive, and I highly value his feedback. Sven guided me to interesting research questions, for example, regarding type checking, formalisms, and empirical evaluation. Often, we have addressed the same problem from differ- ent perspectives (roughly speaking, he as proponent of compositional approaches, me as proponent of annotative approaches) which repeatedly lead to interesting insights and trade-offs, many of which are discussed in this thesis. Second, Don Batory has constantly supported and challenged me. When I vis- ited him at the University of Texas at Austin for my Master’s thesis and observed several problems in my aspect-oriented decomposition of Berkeley DB, he chal- lenged me to look for better variability mechanisms and consistently encouraged me to pursue my early ideas with colors and annotations in CIDE (which went into quite a different direction from his and my work up to that time). Many ideas discussed in this thesis, including visual representation, views, and type checking, emerged in an early raw form already during my visit in his group. Since then, he provided support and ideas for many research topics. It is always a pleasure to work with Don. Third, I want to thank Gunter Saake who gave me the opportunity to pursue a PhD in his group. Gunter has provided an excellent environment for research and has guaranteed me entire freedom. His support for our lecture on product- line implementation for graduate students laid the ground for many interesting projects and young scientists with interest in software product lines. His group proved to be an excellent place for academic development and collaboration. Fourth, I like to express my deepest gratitude to all my colleagues and stu- dents with whom I had the pleasure to collaborate and discuss, including Danilo Beuche, Alexander Dreiling, Janet Feigenspan, Armin Größlinger, Sebastian Gün- ther, Florian Heidenreich, Andy Kenner, Martin Kuhlemann, Thomas Leich, Chris- tian Lengauer, Jörg Liebig, Andreas Lübcke, Mario Pukall, Syed Saif ur Rah- man, Marko Rosenmüller, Malte Rosenthal, Sandro Schulze, Norbert Siegmund, Friedrich Steimann, Sagar Sunkle, Thomas Thüm, and Salvador Trujillo. Of them, I would specifically like to address a special thanks to Martin, Janet, Thomas T., v and Jörg for their great collaboration on significant parts of this thesis; to Marko and Norbert for their support in my ongoing struggle with C and C++; to Armin and Malte for their patient help with Haskell; and to Thomas L. for his contin- uous support with the capabilities on an industrial partner. Last but not least, I gratefully thank my family and friends for their ongoing support far beyond this thesis. vi Contents Contents vii List of Figures xi List of Tables xiii List of Abbreviations xv 1. Introduction 1 1.1. Contribution . .4 1.2. Outline . .5 2. Background 7 2.1. Software product lines . .7 2.2. Domain engineering and application engineering . .8 2.3. Variability modeling . 10 2.4. Separation of concerns . 13 3. Software product line implementation 17 3.1. Compositional approaches . 18 3.1.1. Modularity . 19 3.1.2. Traceability . 21 3.1.3. Language support for variability . 22 3.1.4. Coarse granularity . 22 3.1.5. The optional feature problem . 26 3.1.6. Difficult adoption . 28 3.1.7. Case study: Berkeley DB . 29 3.2. Annotative approaches . 33 3.2.1. Separation of concerns . 35 3.2.2. Obfuscation . 36 3.2.3. Error proneness . 39 3.2.4. Simple and uniform programming model . 40 3.2.5. Fine granularity . 41 3.2.6. Variability despite feature interactions . 41 3.3. Other approaches . 41 vii CONTENTS 3.4. Summary, perspective, and goals . 44 4. Views and visual representation 47 4.1. Integrating a feature model . 47 4.1.1. Implementation . 48 4.1.2. Discussion . 50 4.2. Views . 51 4.2.1. View on a feature . 52 4.2.2. View on a variant . 54 4.2.3. Design decisions . 55 4.2.4. Implementation . 57 4.3. Visual representation . 57 4.3.1. Background colors . 59 4.3.2. Scalability of colors . 61 4.4. Experimental evaluation . 64 4.4.1. Experiment planning . 67 4.4.2. Results . 70 4.4.3. Interpretation . 72 4.5. Related work . 74 4.6. Summary . 79 5. Error detection 81 5.1. Taxonomy . 81 5.2. Disciplined annotations . 84 5.2.1. Basic concept . 84 5.2.2. Detecting disciplined annotations . 85 5.2.3. From string removal to AST transformations . 87 5.2.4. Wrappers . 90 5.2.5. Flexibility vs. safety . 91 5.2.6. Evaluation . 93 5.3. Product-line–aware type system . 99 5.3.1. Type errors in software product lines . 99 5.3.2. Desired properties . 102 5.3.3. Colored Featherweight Java (CFJ) . 103 5.3.4. Alternative features . 119 5.3.5. Beyond Featherweight Java . 124 5.3.6. Evaluation . 126 5.4. Related work . 132 5.5. Summary . 141 viii CONTENTS 6. Comparison and integration 143 6.1. Comparison . 143 6.1.1. Modularity . 143 6.1.2. Traceability . 147 6.1.3. Language integration . 147 6.1.4. Errors . 148 6.1.5. Granularity . 150 6.1.6. Optional feature problem . 150 6.1.7. Uniformity . 151 6.1.8. Adoption . 152 6.2. Perspective: Integrating compositional and annotative approaches . 154 6.2.1. Spectrum between physical and virtual separation . 154 6.2.2. Benefits . 156 6.2.3. Automated refactoring . 158 6.3. Summary . 165 7. Conclusion and future work 167 A. List of case studies 173 A.1. Case studies developed in CIDE . 173 A.2. Forty C programs . 181 Bibliography 183 ix List of Figures 2.1. An (idealized) overview of domain engineering and application en- gineering. .9 2.2. Feature-diagram example of a small database product line. 11 3.1. Two compositional implementations of a stack example with three features. 20 3.2. Example of a fine-grained extensions. 23 3.3. Implementation of fine-grained extensions with Jak. 25 3.4. Modularization of interacting features. 27 3.5. Additional modules to modularize feature interactions. 28 3.6. Code excerpt of Berkeley DB. 34 3.7. Example of scattered configuration knowledge in Vim......... 36 3.8. Java code obfuscated by fine-grained annotations with cpp....... 37 3.9. Preprocessor directives in the code of Femto OS. 38 3.10. Adapted code excerpt of Berkeley DB, with syntax error in variants without Have_Queue ........................... 40 3.11. Preprocessor-based implementation of the expression problem (ex- cerpt). 42 4.1. Annotations in CIDE based on a feature model. 49 4.2. Views on a annotation-based implementation of the expression prob- lem ...................................... 53 4.3. View on feature Transactions in the file structure of Berkeley DB . 58 4.4. Annotations represented by a background color instead of textual annotations. 59 4.5. Representing nested annotations with background colors.
Load more

Recommended publications
  • An Aggregate Computing Approach to Self-Stabilizing Leader Election
    An Aggregate Computing Approach to Self-Stabilizing Leader Election Yuanqiu Mo Jacob Beal Soura Dasgupta University of Iowa Raytheon BBN Technologies University of Iowa⇤ Iowa City, Iowa 52242 Cambridge, MA, USA 02138 Iowa City, Iowa 52242 Email: [email protected] Email: [email protected] Email: [email protected] Abstract—Leader election is one of the core coordination 4" problems of distributed systems, and has been addressed in 3" 1" many different ways suitable for different classes of systems. It is unclear, however, whether existing methods will be effective 7" 1" for resilient device coordination in open, complex, networked 3" distributed systems like smart cities, tactical networks, personal 3" 0" networks and the Internet of Things (IoT). Aggregate computing 2" provides a layered approach to developing such systems, in which resilience is provided by a layer comprising a set of (a) G block (b) C block (c) T block adaptive algorithms whose compositions have been shown to cover a large class of coordination activities. In this paper, Fig. 1. Illustration of three basis block operators: (a) information-spreading (G), (b) information aggregation (C), and (c) temporary state (T) we show how a feedback interconnection of these basis set algorithms can perform distributed leader election resilient to device topology and position changes. We also characterize a key design parameter that defines some important performance a separation of concerns into multiple abstraction layers, much attributes: Too large a value impairs resilience to loss of existing like the OSI model for communication [2], factoring the leaders, while too small a value leads to multiple leaders.
    [Show full text]
  • A Theory of Fault Recovery for Component-Based Models⋆
    A Theory of Fault Recovery for Component-based Models? Borzoo Bonakdarpour1, Marius Bozga2, and Gregor G¨ossler3 1 School of Computer Science, University of Waterloo Email: [email protected] 2 VERIMAG/CNRS, Gieres, France Email: [email protected] 3 INRIA-Grenoble, Montbonnot, France Email: [email protected] Abstract. This paper introduces a theory of fault recovery for component- based models. We specify a model in terms of a set of atomic components incrementally composed and synchronized by a set of glue operators. We define what it means for such models to provide a recovery mechanism, so that the model converges to its normal behavior in the presence of faults (e.g., in self-stabilizing systems). We present a sufficient condition for in- crementally composing components to obtain models that provide fault recovery. We identify corrector components whose presence in a model is essential to guarantee recovery after the occurrence of faults. We also for- malize component-based models that effectively separate recovery from functional concerns. We also show that any model that provides fault recovery can be transformed into an equivalent model, where functional and recovery tasks are modularized in different components. Keywords: Fault-tolerance; Transformation; Separation of concerns; BIP 1 Introduction Fault-tolerance has always been an active line of research in design and imple- mentation of dependable systems. Intuitively, tolerating faults involves providing a system with the means to handle unexpected defects, so that the system meets its specification even in the presence of faults. In this context, the notion of spec- ification may vary depending upon the guarantees that the system must deliver in the presence of faults.
    [Show full text]
  • Cs8603-Distributed Systems Syllabus Unit 3 Distributed Mutex & Deadlock Distributed Mutual Exclusion Algorithms: Introducti
    CS8603-DISTRIBUTED SYSTEMS SYLLABUS UNIT 3 DISTRIBUTED MUTEX & DEADLOCK Distributed mutual exclusion algorithms: Introduction – Preliminaries – Lamport‘s algorithm –Ricart-Agrawala algorithm – Maekawa‘s algorithm – Suzuki–Kasami‘s broadcast algorithm. Deadlock detection in distributed systems: Introduction – System model – Preliminaries –Models of deadlocks – Knapp‘s classification – Algorithms for the single resource model, the AND model and the OR Model DISTRIBUTED MUTUAL EXCLUSION ALGORITHMS: INTRODUCTION INTRODUCTION MUTUAL EXCLUSION : Mutual exclusion is a fundamental problem in distributed computing systems. Mutual exclusion ensures that concurrent access of processes to a shared resource or data is serialized, that is, executed in a mutually exclusive manner. Mutual exclusion in a distributed system states that only one process is allowed to execute the critical section (CS) at any given time. In a distributed system, shared variables (semaphores) or a local kernel cannot be used to implement mutual exclusion. There are three basic approaches for implementing distributed mutual exclusion: 1. Token-based approach. 2. Non-token-based approach. 3. Quorum-based approach. In the token-based approach, a unique token (also known as the PRIVILEGE message) is shared among the sites. A site is allowed to enter its CS if it possesses the token and it continues to hold the token until the execution of the CS is over. Mutual exclusion is ensured because the token is unique. In the non-token-based approach, two or more successive rounds of messages are exchanged among the sites to determine which site will enter the CS next. Mutual exclusion is enforced because the assertion becomes true only at one site at any given time.
    [Show full text]
  • Separation of Concerns in Multi-Language Specifications
    INFORMATICA, 2002, Vol. 13, No. 3, 255–274 255 2002 Institute of Mathematics and Informatics, Vilnius Separation of Concerns in Multi-language Specifications Robertas DAMAŠEVICIUS,ˇ Vytautas ŠTUIKYS Software Engineering Department, Kaunas University of Technology Student¸u 50, 3031 Kaunas, Lithuania e-mail: [email protected], [email protected] Received: April 2002 Abstract. We present an analysis of the separation of concerns in multi-language design and multi- language specifications. The basis for our analysis is the paradigm of the multi-dimensional sepa- ration of concerns, which claims that multiple dimensions of concerns in a design should be imple- mented independently. Multi-language specifications are specifications where different concerns of a design are implemented using separate languages as follows. (1) Target language(s) implement domain functionality. (2) External (or scripting, meta-) language(s) implement generalisation of the repetitive design features, introduce variations, and integrate components into a design. We present case studies and experimental results for the application of the multi-language specifications in hardware design. Key words: multi-language design, separation of concerns, meta-programming, scripting, hardwa- re design. 1. Introduction Today the high-level design of a hardware (HW) system is usually based either on the usage of the pure HW description language (HDL) (e.g., VHDL, Verilog), or the algo- rithmic one (e.g., C++, SystemC), or both. The emerging problems are similar for both, the HW and software (SW) domains. For example, the increasing complexity of SW and HW designs urges the designers and researchers to seek for the new design methodolo- gies.
    [Show full text]
  • Multi-Dimensional Concerns in Parallel Program Design
    Multi-Dimensional Concerns in Parallel Program Design Parallel programming is difficult, thus design patterns. Despite rapid advances in parallel hardware performance, the full potential of processing power is not being exploited in the community for one clear reason: difficulty of designing parallel software. Identifying tasks, designing parallel algorithm, and managing the balanced load among the processing units has been a daunting task for novice programmers, and even the experienced programmers are often trapped with design decisions that underachieve in potential peak performance. Over the last decade there have been several approaches in identifying common patterns that are repeatedly used in parallel software design process. Documentation of these “design patterns” helps the programmers by providing definition, solution and guidelines for common parallelization problems. Such patterns can take the form of templates in software tools, written paragraphs with detailed description, or even charts, diagrams and examples. The current parallel patterns prove to be ineffective. In practice, however, the parallel design patterns identified thus far [over the last two decades!] contribute little—if none at all—to development of non-trivial parallel software. In short, the parallel design patterns are too trivial and fail to give detailed guidelines for specific parameters that can affect the performance of wide range of complex problem requirements. By experience in the community, it is coming to a consensus that there are only limited number of patterns; namely pipeline, master & slave, divide & conquer, geometric, replicable, repository, and not many more. So far the community efforts were focused on discovering more design patterns, but new patterns vary a little and fall into range that is not far from one of the patterns mentioned above.
    [Show full text]
  • Using Architectural Styles in Design ‹ the Nature of Computation ‹ the Quality Concerns
    Which Architectural Style should be used? The selection of software architectural style should take into consideration of two factors: Using Architectural Styles in Design The nature of computation The quality concerns Lecture 6 U08182 © Peter Lo 2010 1 U08182 © Peter Lo 2010 2 In this lecture you will learn: The selection of software architectural style should take into consideration of two • Use of software architectural styles in design factors: • Selection of appropriate architectural style • The nature of the computation problem to be solved. e.g. the input/output data structure and features, the required functions of the system, etc. • Combinations of styles • The quality concerns that the design of the system must take into • Case studies consideration, such as performance, reliability, security, maintenance, reuse, • Case study 1: Keyword Frequency Vector (KFV) modification, interoperability, etc. • Case study 2: Keyword in Context (KWIC) 1 2 Characteristic Features of Architectural Behavioral Features of Architectural Styles Styles Control Topology Synchronicity Data Topology Data Access Mode Control/Data Interaction Topology Data Flow Continuity Control/Data Interaction Direction Binding Time U08182 © Peter Lo 2010 3 U08182 © Peter Lo 2010 4 Control Topology: Synchronicity: • How dependent are the components' action upon each other's control state? • What geometric form does the control flow for the systems of the style take? • Lockstep – One component's state implies the other component's state. • E.g. In the main-program-and-subroutine style, components must be organized must • Synchronous – Components synchronies at certain states to make sure they are in the be organized into a hierarchical structure. synchronized states at the same time in order to cooperate, but the relationships on other states are not predictable.
    [Show full text]
  • Preserving Separation of Concerns Through Compilation
    Preserving Separation of Concerns through Compilation A Position Paper Hridesh Rajan Robert Dyer Youssef Hanna Harish Narayanappa Dept. of Computer Science Iowa State University Ames, IA 50010 {hridesh, rdyer, ywhanna, harish}@iastate.edu ABSTRACT tempt the programmer to switch to another task entirely (e.g. Today’s aspect-oriented programming (AOP) languages pro- email, Slashdot headlines). vide software engineers with new possibilities for keeping The significant increase in incremental compilation time conceptual concerns separate at the source code level. For a is because when there is a change in a crosscutting concern, number of reasons, current aspect weavers sacrifice this sep- the effect ripples to the fragmented locations in the com- aration in transforming source to object code (and thus the piled program forcing their re-compilation. Note that the very term weaving). In this paper, we argue that sacrificing system studied by Lesiecki [12] can be classified as a small modularity has significant costs, especially in terms of the to medium scale system with just 700 classes and around speed of incremental compilation and in testing. We argue 70 aspects. In a large-scale system, slowdown in the de- that design modularity can be preserved through the map- velopment process can potentially outweigh the benefits of ping to object code, and that preserving it can have signifi- separation of concerns. cant benefits in these dimensions. We present and evaluate a Besides incremental compilation, loss of separation of con- mechanism for preserving design modularity in object code, cerns also makes unit testing of AO programs difficult. The showing that doing so has potentially significant benefits.
    [Show full text]
  • Versatility and Efficiency in Self-Stabilizing Distributed Systems
    Versatility and Efficiency in Self-Stabilizing Distributed Systems Stéphane Devismes To cite this version: Stéphane Devismes. Versatility and Efficiency in Self-Stabilizing Distributed Systems. Distributed, Parallel, and Cluster Computing [cs.DC]. Université Grenoble Alpes, 2020. tel-03080444v4 HAL Id: tel-03080444 https://hal.archives-ouvertes.fr/tel-03080444v4 Submitted on 21 Sep 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. HABILITATION À DIRIGER DES RECHERCHES Spécialité : Informatique Arrêté ministériel : 23 Novembre 1988 Présentée par Stéphane Devismes Habilitation préparée au sein du laboratoire VERIMAG et de l’École Doctorale Mathématiques, Sciences et Technologies de l’Information, Informatique Versatility and Efficiency in Self-Stabilizing Distributed Systems Généralité et Efficacité dans les Systèmes Distribués Autostabilisants Habilitation soutenue publiquement le 17 décembre 2020, devant le jury composé de : Denis TRYSTRAM Professeur, Grenoble INP, Président Toshimitsu MASUZAWA Professeur, Osaka University, Rapporteur Achour MOSTÉFAOUI
    [Show full text]
  • Separation of Concerns for Dependable Software Design
    Separation of Concerns for Dependable Software Design Daniel Jackson and Eunsuk Kang MIT Computer Science and Artificial Intelligence Laboratory 32 Vassar Street, Cambridge, MA 02139 [email protected] ABSTRACT tiously includes collection of detailed statistics and explicit mechanisms for adjusting the process accordingly. For ‘mixed-criticality’ systems that have both critical and non-critical functions, the greatest leverage on dependabil- Testing is used for two very different purposes. On the one ity may be at the design level. By designing so that each hand, it is used to find bugs. Structural tests exploit knowl- critical requirement has a small trusted base, the cost of the edge of the structure of the software to identify bugs in analysis required for a dependability case might be dra- known categories. A mutation test, for example, might fo- matically reduced. An implication of this approach is that cus on the possibility that the wrong operator was selected conventional object-oriented design may be a liability, be- for an expression; a regression test is designed to detect the cause it leads to ‘entanglement’, and an approach based on reoccurrence of a particular flaw. For this kind of testing, a separating services may be preferable. successful test is one that fails, and thus identifies a bug. Categories and Subject Descriptors On the other hand, testing can be used to provide evidence D.2.2 [Software Engineering]: Design Tools and Tech- of dependability. In this case, tests focused on particular niques; D.2.4 Software/Program Verification; D.2.10 De- known bug categories are less useful (since a failure might sign.
    [Show full text]
  • Session 8: from Analysis and Design to Software Architectures (Part I Addendum)
    Software Engineering G22.2440-001 Session 8 – Sub-Topic 1 From Analysis and Design to Software Architectures (Part I Addendum) Dr. Jean-Claude Franchitti New York University Computer Science Department Courant Institute of Mathematical Sciences 1 Agenda • Towards Agile Enterprise Architecture Models • Building an Object Model Using UML • Architectural Analysis • Design Patterns • Architectural Patterns • Architecture Design Methodology • Achieving Optimum-Quality Results • Selecting Kits and Frameworks • Using Open Source vs. Commercial Infrastructures 2 1 Part I Towards Agile Enterprise Architecture Models 3 There is an Urgent Need for More Reliable, Concept-driven, Early Requirements Processes (review) • SDLC Process model frameworks have matured and converged significantly on effective practices in system development phases, however, they are still weakest on the front-end. RUP Phases: Inception ElaborationConstruction Transition • Project Planning • Hi-level languages • QA Methods • ??? • Use Case Models • Frameworks • Test environments •… • Object Models •IDEs • Issue support tools • Data Models • n-Tier Architectures • Usability • UI prototypes • Design Patterns Engineering •… •… •… MSF Phases: Envisioning PlanningDeveloping Stabilizing / Deploying Less mature methods / support More mature methods / support 4 2 XP Practices (review) • The Planning Game – determine the scope of the next release, based on business priorities and technical estimates. • Small Releases – every release should be as small as possible, containing the most valuable business requirements. • Metaphor – guide all development with a simple, shared story of how the whole system works. • Simple Design – design for the current functionality, not future needs, and make the design as simple as possible for that functionality (YAGNI). • Refactoring – ongoing redesign of software to improve its responsiveness to change. • Testing – developers write the unit tests before the code; unit tests are run “continuously”; customers write the functional tests.
    [Show full text]
  • The Shadow Knows: Refinement and Security in Sequential Programs *
    Science of Computer Programming Volume 74, Issue 8, 1 June 2009, Pages 629-653 Special Issue on Mathematics of Program Construction (MPC 2006) The Shadow Knows: Refinement and security in sequential programs Carroll Morgan 1 Sch. Comp. Sci. & Eng., Uni. NSW, Sydney 2052 Australia Abstract Stepwise refinement is a crucial conceptual tool for system development, encour- aging program construction via a number of separate correctness-preserving stages which ideally can be understood in isolation. A crucial conceptual component of security is an adversary’s ignorance of concealed information. We suggest a novel method of combining these two ideas. Our suggestion is based on a mathematical definition of “ignorance-preserving” refinement that extends classical refinement by limiting an adversary’s access to concealed information: moving from specification to implementation should never increase that access. The novelty is the way we achieve this in the context of se- quential programs. Specifically we give an operational model (and detailed justification for it), a basic sequential programming language and its operational semantics in that model, a “logic of ignorance” interpreted over the same model, then a program-logical semantics bringing those together — and finally we use the logic to establish, via refinement, the correctness of a real (though small) protocol: Rivest’s Oblivious Transfer. A previous report treated Chaum’s Dining Cryptoraphers similarly. In passing we solve the Refinement Paradox for sequential programs. Key words: Security, privacy, Hoare logic, specification, implementation, logic of knowledge This is an extension of an earlier report [1]. Email address: [email protected] (Carroll Morgan). 1 We acknowledge the support of the Aust.
    [Show full text]
  • A Structured Programming Approach to Data Ebook
    A STRUCTURED PROGRAMMING APPROACH TO DATA PDF, EPUB, EBOOK Coleman | 222 pages | 27 Aug 2012 | Springer-Verlag New York Inc. | 9781468479874 | English | New York, NY, United States A Structured Programming Approach to Data PDF Book File globbing in Linux. It seems that you're in Germany. De Marco's approach [13] consists of the following objects see figure : [12]. Get print book. Bibliographic information. There is no reason to discard it. No Downloads. Programming is becoming a technology, a theory known as structured programming is developing. Visibility Others can see my Clipboard. From Wikipedia, the free encyclopedia. ALGOL 60 implementation Call stack Concurrency Concurrent programming Cooperating sequential processes Critical section Deadly embrace deadlock Dining philosophers problem Dutch national flag problem Fault-tolerant system Goto-less programming Guarded Command Language Layered structure in software architecture Levels of abstraction Multithreaded programming Mutual exclusion mutex Producer—consumer problem bounded buffer problem Program families Predicate transformer semantics Process synchronization Self-stabilizing distributed system Semaphore programming Separation of concerns Sleeping barber problem Software crisis Structured analysis Structured programming THE multiprogramming system Unbounded nondeterminism Weakest precondition calculus. Comments and Discussions. The code block runs at most once. Latest Articles. Show all. How any system is developed can be determined through a data flow diagram. The result of structured analysis is a set of related graphical diagrams, process descriptions, and data definitions. Therefore, when changes are made to that type of data, the corresponding change must be made at each location that acts on that type of data within the program. It means that the program uses single-entry and single-exit elements.
    [Show full text]