PPT-Traps, Exceptions, System Calls, & Privileged Mode

Hakim Weatherspoon CS 3410 Spring 2011 Computer Science Cornell University PampH Chapter 49 pages 509515 appendix B7 Operating Systems Control Transfers Control Transfers to OS Case 1 Program invokes OS. By Kevin Moroz . VP Technology . Snom Inc. . What are we trying to protect? . Denial of Service – the phone system is down!. T. oll Fraud – a very large phone bill! . Eavesdropping – someone listening to your calls. . Hakim Weatherspoon. CS 3410, . Spring 2012. Computer Science. Cornell University. P&H . Chapter. 4.9, pages 509–515, appendix B.7. Administrivia. Project3 available now. Design Doc due . next week. : Flexible System Call Scheduling with Exception-Less System Calls. Livio. . Soares. , Michael . Stumm. University of Toronto. Presented by Md. . Maksudul. . Alam. 29 September, 2011. CS 5204. Mechanism used by an . Types of exceptions. Checked exceptions:.  A checked exception is an exception that is typically a user error or a problem that cannot be foreseen by the programmer. For example, if a file is to be opened, but the file cannot be found, an exception occurs. These exceptions cannot simply be ignored at the time of compilation. Perrig. . & Torsten Hoefler. Networks and Operating . Systems . (252-0062-00). ‏ . Chapter . 1: . Introduction to Operating Systems. Two parts: . Networks – Adrian . Perrig. Operating Systems – Torsten Hoefler. P&H Chapter 4.9, pages 509–515, appendix B.7. Operating Systems. Control Transfers. Control Transfers to OS. Case 1: Program invokes OS. eg. : . sbrk. (), . mmap. (), sleep(). Like a function call: invoke, do stuff, return results. Exploration (PIE) Model . REVISITED . . Sherry K. Watt, Cindy Ann . Kilgo. , Kira Pasquesi, and John A. Mueller. ACPA – Tampa, FL . – March . 6, 2015 . Program outline. Opening reflection. Privileged Identity Exploration (PIE) model. Handling errors using Java’s exception handling mechanism. Approaches For Dealing With Error Conditions. Use branches/decision making and return values. Use Java’s exception handling mechanism. Class . Privileged Access Management. <Date/Presenter>. AGENDA. Bomgar Overview. Bomgar Privileged Access Management Solution. Capabilities. Deployment. Integrations. Demo. Q&A. #1 . in Enterprise Remote Support market share. a quick review… . What happened before exceptions?. must remember to check return value. OR, must pass label/exception handler to every function. Caller. Function. return status. Caller. Function. label to subprogram. Handling errors using Java’s exception handling mechanism. Approaches For Dealing With Error Conditions. Use branches/decision making and return values. Use Java’s exception handling mechanism. Class . Syscalls , exceptions, and interrupts, …oh my! Hakim Weatherspoon CS 3410 Computer Science Cornell University [ Altinbuken , Weatherspoon, Bala , Bracy , McKee, and Sirer ] Announcements P4-Buffer Overflow is due tomorrow Syscalls , exceptions, and interrupts, …oh my! Hakim Weatherspoon CS 3410 Computer Science Cornell University [ Altinbuken , Weatherspoon, Bala , Bracy , McKee, and Sirer ] Announcements P4-Buffer Overflow is due tomorrow Debugging for non-Virtualized Systems . How it’s normally done . App or Lib. (non-privileged). OS Kernel. (privileged). App or Lib. (non-privileged). SW. Debugger. (e.g. GDB) . User-Mode debugging.