The Design and Implementation of the Freebsd® Operating System
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Kutrace: Where Have All the Nanoseconds Gone?
KUTrace: Where have all the nanoseconds gone? Richard Sites, Invited Professor EPFL 2017.10.27 Tracing Summit 2017, Prague Richard Sites 2017.10.27 Outline Observability problem statement KUTrace solution Tracing design goals Goals drive the design Results Display Design Comparisons Conclusions Richard Sites 2017.10.27 Observability problem statement Richard Sites 2017.10.27 3 Problem statement This talk is about tail latency in real user-facing datacenter transactions. It is not about batch processing throughput, nor about benchmarks. Context: A datacenter of perhaps 20,000 servers running software services that spread work for a user-facing transaction across a few hundred or thousand machines in parallel. Each server handles hundreds of transactions per second. Some transactions are unusually slow, but not repeatably. Slow transactions occur unpredictably, but there are several per minute. We wish to observe where all the time goes in such transactions, and observe why they are slow. Richard Sites 2017.10.27 Problem statement ☞ Some transactions are unusually slow, but not repeatably. ∴ There is some source of interference just before or during a slow transaction. Understanding tail latency requires complete traces of CPU events over a few minutes, with small enough CPU and memory overhead to be usable under busiest-hour live load. Existing tracing tools have much-too-high overhead. Problem: build better tail-latency observation tools Richard Sites 2017.10.27 KUTrace solution Richard Sites 2017.10.27 6 KUTrace solution KUTrace uses minimal Linux kernel patches on a single server to trace every transition between kernel- and user-mode execution, on every CPU core, with small enough overhead to use routinely on live loads. -
Proceedings of the Bsdcon 2002 Conference
USENIX Association Proceedings of the BSDCon 2002 Conference San Francisco, California, USA February 11-14, 2002 THE ADVANCED COMPUTING SYSTEMS ASSOCIATION © 2002 by The USENIX Association All Rights Reserved For more information about the USENIX Association: Phone: 1 510 528 8649 FAX: 1 510 548 5738 Email: [email protected] WWW: http://www.usenix.org Rights to individual papers remain with the author or the author's employer. Permission is granted for noncommercial reproduction of the work for educational or research purposes. This copyright notice must be included in the reproduced paper. USENIX acknowledges all trademarks herein. Rethinking /devand devices in the UNIX kernel Poul-Henning Kamp <[email protected]> The FreeBSD Project Abstract An outstanding novelty in UNIX at its introduction was the notion of ‘‘a file is a file is a file and evenadevice is a file.’’ Going from ‘‘hardware only changes when the DEC Field engineer is here’’to‘‘my toaster has USB’’has put serious strain on the rather crude implementation of the ‘‘devices as files’’concept, an implementation which has survivedpractically unchanged for 30 years in most UNIX variants. Starting from a high-levelviewofdevices and the semantics that have grown around them overthe years, this paper takes the audience on a grand tour of the redesigned FreeBSD device-I/O system, to convey anoverviewofhow itall fits together,and to explain whythings ended up as theydid, howtouse the newfeatures and in particular hownot to. 1. Introduction tax and meaning, so that a program expecting a file name as a parameter can be passed a device name; There are really only twofundamental ways to concep- finally,special files are subject to the same protec- tualise I/O devices in an operating system: The usual tion mechanism as regular files. -
Introduction to Debugging the Freebsd Kernel
Introduction to Debugging the FreeBSD Kernel John H. Baldwin Yahoo!, Inc. Atlanta, GA 30327 [email protected], http://people.FreeBSD.org/˜jhb Abstract used either directly by the user or indirectly via other tools such as kgdb [3]. Just like every other piece of software, the The Kernel Debugging chapter of the FreeBSD kernel has bugs. Debugging a ker- FreeBSD Developer’s Handbook [4] covers nel is a bit different from debugging a user- several details already such as entering DDB, land program as there is nothing underneath configuring a system to save kernel crash the kernel to provide debugging facilities such dumps, and invoking kgdb on a crash dump. as ptrace() or procfs. This paper will give a This paper will not cover these topics. In- brief overview of some of the tools available stead, it will demonstrate some ways to use for investigating bugs in the FreeBSD kernel. FreeBSD’s kernel debugging tools to investi- It will cover the in-kernel debugger DDB and gate bugs. the external debugger kgdb which is used to perform post-mortem analysis on kernel crash dumps. 2 Kernel Crash Messages 1 Introduction The first debugging service the FreeBSD kernel provides is the messages the kernel prints on the console when the kernel crashes. When a userland application encounters a When the kernel encounters an invalid condi- bug the operating system provides services for tion (such as an assertion failure or a memory investigating the bug. For example, a kernel protection violation) it halts execution of the may save a copy of the a process’ memory current thread and enters a “panic” state also image on disk as a core dump. -
BSD UNIX Toolbox: 1000+ Commands for Freebsd, Openbsd and Netbsd Christopher Negus, Francois Caen
To purchase this product, please visit https://www.wiley.com/en-bo/9780470387252 BSD UNIX Toolbox: 1000+ Commands for FreeBSD, OpenBSD and NetBSD Christopher Negus, Francois Caen E-Book 978-0-470-38725-2 April 2008 $16.99 DESCRIPTION Learn how to use BSD UNIX systems from the command line with BSD UNIX Toolbox: 1000+ Commands for FreeBSD, OpenBSD and NetBSD. Learn to use BSD operation systems the way the experts do, by trying more than 1,000 commands to find and obtain software, monitor system health and security, and access network resources. Apply your newly developed skills to use and administer servers and desktops running FreeBSD, OpenBSD, NetBSD, or any other BSD variety. Become more proficient at creating file systems, troubleshooting networks, and locking down security. ABOUT THE AUTHOR Christopher Negus served for eight years on development teams for the UNIX operating system at the AT&T labs, where UNIX was created and developed. He also worked with Novell on UNIX and UnixWare development. Chris is the author of the bestselling Fedora and Red Hat Linux Bible series, Linux Toys II, Linux Troubleshooting Bible, and Linux Bible 2008 Edition. Francois Caen hosts and manages business application infrastructures through his company Turbosphere LLC. As an open- source advocate, he has lectured on OSS network management and Internet services, and served as president of the Tacoma Linux User Group. He is a Red Hat Certified Engineer (RHCE). To purchase this product, please visit https://www.wiley.com/en-bo/9780470387252. -
Ebook - Informations About Operating Systems Version: August 15, 2006 | Download
eBook - Informations about Operating Systems Version: August 15, 2006 | Download: www.operating-system.org AIX Internet: AIX AmigaOS Internet: AmigaOS AtheOS Internet: AtheOS BeIA Internet: BeIA BeOS Internet: BeOS BSDi Internet: BSDi CP/M Internet: CP/M Darwin Internet: Darwin EPOC Internet: EPOC FreeBSD Internet: FreeBSD HP-UX Internet: HP-UX Hurd Internet: Hurd Inferno Internet: Inferno IRIX Internet: IRIX JavaOS Internet: JavaOS LFS Internet: LFS Linspire Internet: Linspire Linux Internet: Linux MacOS Internet: MacOS Minix Internet: Minix MorphOS Internet: MorphOS MS-DOS Internet: MS-DOS MVS Internet: MVS NetBSD Internet: NetBSD NetWare Internet: NetWare Newdeal Internet: Newdeal NEXTSTEP Internet: NEXTSTEP OpenBSD Internet: OpenBSD OS/2 Internet: OS/2 Further operating systems Internet: Further operating systems PalmOS Internet: PalmOS Plan9 Internet: Plan9 QNX Internet: QNX RiscOS Internet: RiscOS Solaris Internet: Solaris SuSE Linux Internet: SuSE Linux Unicos Internet: Unicos Unix Internet: Unix Unixware Internet: Unixware Windows 2000 Internet: Windows 2000 Windows 3.11 Internet: Windows 3.11 Windows 95 Internet: Windows 95 Windows 98 Internet: Windows 98 Windows CE Internet: Windows CE Windows Family Internet: Windows Family Windows ME Internet: Windows ME Seite 1 von 138 eBook - Informations about Operating Systems Version: August 15, 2006 | Download: www.operating-system.org Windows NT 3.1 Internet: Windows NT 3.1 Windows NT 4.0 Internet: Windows NT 4.0 Windows Server 2003 Internet: Windows Server 2003 Windows Vista Internet: Windows Vista Windows XP Internet: Windows XP Apple - Company Internet: Apple - Company AT&T - Company Internet: AT&T - Company Be Inc. - Company Internet: Be Inc. - Company BSD Family Internet: BSD Family Cray Inc. -
Debugging Kernel Problems
Debugging Kernel Problems by GregLehey Edition for AsiaBSDCon 2004 Taipei, 13 March 2004 Debugging Kernel Problems by GregLehey([email protected]) Copyright © 1995-2004 GregLehey 3Debugging Kernel Problems Preface Debugging kernel problems is a black art. Not manypeople do it, and documentation is rare, in- accurate and incomplete. This document is no exception: faced with the choice of accuracyand completeness, I chose to attempt the latter.Asusual, time was the limiting factor,and this draft is still in beta status. This is a typical situation for the whole topic of kernel debugging: building debug tools and documentation is expensive,and the people who write them are also the people who use them, so there'satendencytobuild as much of the tool as necessary to do the job at hand. If the tool is well-written, it will be reusable by the next person who looks at a particular area; if not, it might fall into disuse. Consider this book a starting point for your own develop- ment of debugging tools, and remember: more than anywhere else, this is an area with ``some as- sembly required''. Debugging Kernel Problems 4 1 Introduction Operating systems fail. All operating systems contain bugs, and theywill sometimes cause the system to behave incorrectly.The BSD kernels are no exception. Compared to most other oper- ating systems, both free and commercial, the BSD kernels offer a large number of debugging tools. This tutorial examines the options available both to the experienced end user and also to the developer. In this tutorial, we’ll look at the following topics: • Howand whykernels fail. -
NSA Security-Enhanced Linux (Selinux)
Integrating Flexible Support for Security Policies into the Linux Operating System http://www.nsa.gov/selinux Stephen D. Smalley [email protected] Information Assurance Research Group National Security Agency ■ Information Assurance Research Group ■ 1 Outline · Motivation and Background · What SELinux Provides · SELinux Status and Adoption · Ongoing and Future Development ■ Information Assurance Research Group ■ 2 Why Secure the Operating System? · Information attacks don't require a corrupt user. · Applications can be circumvented. · Must process in the clear. · Network is too far. · Hardware is too close. · End system security requires a secure OS. · Secure end-to-end transactions requires secure end systems. ■ Information Assurance Research Group ■ 3 Mandatory Access Control · A ªmissing linkº of security in current operating systems. · Defined by three major properties: ± Administratively-defined security policy. ± Control over all subjects (processes) and objects. ± Decisions based on all security-relevant information. ■ Information Assurance Research Group ■ 4 Discretionary Access Control · Existing access control mechanism of current OSes. · Limited to user identity / ownership. · Vulnerable to malicious or flawed software. · Subject to every user©s discretion (or whim). · Only distinguishes admin vs. non-admin for users. · Only supports coarse-grained privileges for programs. · Unbounded privilege escalation. ■ Information Assurance Research Group ■ 5 What can MAC offer? · Strong separation of security domains · System, application, and data integrity · Ability to limit program privileges · Processing pipeline guarantees · Authorization limits for legitimate users ■ Information Assurance Research Group ■ 6 MAC Implementation Issues · Must overcome limitations of traditional MAC ± More than just Multi-Level Security / BLP · Policy flexibility required ± One size does not fit all! · Maximize security transparency ± Compatibility for applications and existing usage. -
Jitk: a Trustworthy In-Kernel Interpreter Infrastructure
Jitk: A trustworthy in-kernel interpreter infrastructure Xi Wang, David Lazar, Nickolai Zeldovich, Adam Chlipala, Zachary Tatlock MIT and University of Washington Modern OSes run untrusted user code in kernel In-kernel interpreters - Seccomp: sandboxing (Linux) - BPF: packet filtering - INET_DIAG: socket monitoring - Dtrace: instrumentation Critical to overall system security - Any interpreter bugs are serious! 2/30 Many bugs have been found in interpreters Kernel space bugs - Control flow errors: incorrect jump offset, ... - Arithmetic errors: incorrect result, ... - Memory errors: buffer overflow, ... - Information leak: uninitialized read Kernel-user interface bugs - Incorrect encoding/decoding User space bugs - Incorrect input generated by tools/libraries Some have security consequences: CVE-2014-2889, ... See our paper for a case study of bugs 3/30 How to get rid of all these bugs at once? Theorem proving can help kill all these bugs seL4: provably correct microkernel [SOSP'09] CompCert: provably correct C compiler [CACM'09] This talk: Jitk - Provably correct interpreter for running untrusted user code - Drop-in replacement for Linux's seccomp - Built using Coq proof assistant + CompCert 5/30 Theorem proving: overview specification proof implementation Proof is machine-checkable: Coq proof assistant Proof: correct specification correct implementation Specification should be much simpler than implementation 6/30 Challenges What is the specification? How to translate systems properties into proofs? How to extract a running -
An Access Control Model for Preventing Virtual Machine Escape Attack
future internet Article An Access Control Model for Preventing Virtual Machine Escape Attack Jiang Wu ,*, Zhou Lei, Shengbo Chen and Wenfeng Shen School of Computer Engineering and Science, Shanghai University, Shanghai 200444, China; [email protected] (Z.L.); [email protected] (S.C.); [email protected] (W.S.) * Correspondence: [email protected]; Tel: +86-185-0174-6348 Academic Editor: Luis Javier Garcia Villalba Received: 26 March 2017; Accepted: 23 May 2017; Published: 2 June 2017 Abstract: With the rapid development of Internet, the traditional computing environment is making a big migration to the cloud-computing environment. However, cloud computing introduces a set of new security problems. Aiming at the virtual machine (VM) escape attack, we study the traditional attack model and attack scenarios in the cloud-computing environment. In addition, we propose an access control model that can prevent virtual machine escape (PVME) by adapting the BLP (Bell-La Padula) model (an access control model developed by D. Bell and J. LaPadula). Finally, the PVME model has been implemented on full virtualization architecture. The experimental results show that the PVME module can effectively prevent virtual machine escape while only incurring 4% to 8% time overhead. Keywords: virtual security; virtual machine escape; access control; BLP model; PVME model 1. Introduction Cloud computing treats IT resources, data and applications as a service provided to the user through network, which is a change in the way of how data is modeled. Currently, the world’s leading IT companies have developed and published their own cloud strategies, such as Google, Amazon, and IBM. -
BSD UNIX Toolbox 1000+ Commands for Freebsd, Openbsd
76034ffirs.qxd:Toolbox 4/2/08 12:50 PM Page iii BSD UNIX® TOOLBOX 1000+ Commands for FreeBSD®, OpenBSD, and NetBSD®Power Users Christopher Negus François Caen 76034ffirs.qxd:Toolbox 4/2/08 12:50 PM Page ii 76034ffirs.qxd:Toolbox 4/2/08 12:50 PM Page i BSD UNIX® TOOLBOX 76034ffirs.qxd:Toolbox 4/2/08 12:50 PM Page ii 76034ffirs.qxd:Toolbox 4/2/08 12:50 PM Page iii BSD UNIX® TOOLBOX 1000+ Commands for FreeBSD®, OpenBSD, and NetBSD®Power Users Christopher Negus François Caen 76034ffirs.qxd:Toolbox 4/2/08 12:50 PM Page iv BSD UNIX® Toolbox: 1000+ Commands for FreeBSD®, OpenBSD, and NetBSD® Power Users Published by Wiley Publishing, Inc. 10475 Crosspoint Boulevard Indianapolis, IN 46256 www.wiley.com Copyright © 2008 by Wiley Publishing, Inc., Indianapolis, Indiana Published simultaneously in Canada ISBN: 978-0-470-37603-4 Manufactured in the United States of America 10 9 8 7 6 5 4 3 2 1 Library of Congress Cataloging-in-Publication Data is available from the publisher. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600. Requests to the Publisher for permis- sion should be addressed to the Legal Department, Wiley Publishing, Inc., 10475 Crosspoint Blvd., Indianapolis, IN 46256, (317) 572-3447, fax (317) 572-4355, or online at http://www.wiley.com/go/permissions. -
Advanced Integration
ZFS: Advanced Integration Allan Jude -- [email protected] @allanjude Introduction: Allan Jude • 16 Years as FreeBSD Server Admin • FreeBSD src/doc committer (ZFS, installer, boot loader, GELI, bhyve, libucl, libxo) • FreeBSD Core Team (July 2016 - 2018) • Co-Author of “FreeBSD Mastery: ZFS” and “FreeBSD Mastery: Advanced ZFS” with Michael W. Lucas • Architect of the ScaleEngine CDN (HTTP and Video) • Host of weekly BSDNow.tv Podcast • Personally Responsible for 1000 TB of ZFS Storage ZFS: What Is It? • ZFS is a filesystem with a built in volume manager (combine multiple disks into a pool) • Space from the pool is thin-provisioned to multiple filesystems or block volumes (zvols) • All data and metadata is checksummed • Optional transparent compression • Copy-on-Write with snapshots and clones • Each filesystem is tunable with properties Snapshots and Clones • Copy-on-Write means snapshots are instant • Blocks referenced by a snapshot kept when they are removed from the live filesystem • Snapshots allows you to access the file- system as it was when snapshot was taken • No performance impact on reads/writes • Take no additional space until blocks change • Clones allow you to “fork” a filesystem Boot Environments • If the root filesystem is on ZFS, you can snapshot before an upgrade, then clone it • You now have 2 filesystems, one before the upgrade, and one after. Only takes the space of blocks that changed • FreeBSD boot loader allows you to select which one to use from a menu • Upgrade without fear, can always rollback Boot Environment Tooling • Existing tool: sysadmin/beadm • GSoC 2017: be(8) and libbe(3) • New tool supports better management of filesystem properties for boot integration • New tool will support “deep” boot environments. -
Mandoc: Becoming the Main BSD Manual Toolbox
mandoc: becoming the main BSD manual toolbox BSDCan 2015, June 13, Ottawa Ingo Schwarze <[email protected]> Cynthia Livingston’sOTTB “Bedifferent” (c) 2013 C. Livingston (with permission) > Ingo Schwarze: mandoc page 2: INTROI BSDCan 2015, June 13, Ottawa Brief history of UNIX documentation • The key point: All documentation in one place and one format. Easy to find, uniform and easy to read and write. Be correct, complete, concise. • 1964: RUNOFF/roffmarkup syntax by Jerome H. Saltzer,MIT. Unobtrusive,diff(1)-friendly,easy to hand-edit, simple tools, high quality output. • 1971: Basic manual structure by Ken Thompson and Dennis Ritchie for the AT&T Version 1 UNIX manuals, Bell Labs. • 1979: man(7) physical markup language for AT&T Version 7 UNIX. • 1989: mdoc(7) semantic markup by Cynthia Livingston for 4.3BSD-Reno. Powerful, self-contained, portable. • 1989: GNU troffbyJames Clarke. • 2001: mdoc(7) rewrite by Werner Lemberg and Ruslan Ermilovfor groff-1.17. • 2008: mandoc(1) started by Kristaps Dzonsons. • 2010: mandoc(1) is the only documentation formatter in the OpenBSD base system. • 2014: mandoc(1) used by default in OpenBSD, FreeBSD, NetBSD, illumos. 16:19:30 What is the mandoc toolbox? → < > Ingo Schwarze: mandoc page 3: INTROIIBSDCan 2015, June 13, Ottawa What is the mandoc toolbox? User perspective:man(1), the manual viewer One comprehensive tool! Normal operation always proceeds in three steps: 1. Find one or more manuals in the file system or using a database by manual name — man(1) — or by search query — apropos(1) =man -k The result of this step can be printed out with man -w.