System Programming
Abdul-Rahman Mahmood
http://alphapeeler.sourceforge.net http://pk.linkedin.com/in/armahmood abdulmahmood-sss twitter.com/alphapeeler alphapeeler.sourceforge.net/pubkeys/pkey.htm
VC++, VB, ASP
1 About the instructor:Roles/Skills
ROLES # Y ORGANIZATIONS Chief Technology Officer 4.2 Riysoft PVT LTD Consultant / Head Crypto Div– MOD 3.0 Ministry of Defense , RikSof, SecureBytes, RT Japan, Pyntail, SSS
Proj Manager, Team Lead, OG-I 1.5 National Bank – Head Office (IT Group) Proj Coord / Analyst / Tech Lead 2.5 Plexus (Global Partner - WSI International, Canada.) QMR / Proj / Process / HR Manager 1.5 Softech Worldwide L.L.C. (A US based software house )
IT Manager (Computer Engineer) 1.5 Peritech Intl.– Nagoya, Japan Sr. Software Engineer 3.5 Infinilogic Pvt. Ltd. (A UK based software house)
TECHNICAL SKILLS DETAILS
Languages & Tools C++, C#, ObjectiveC, PHP,ASP,VC,VB,COM,MTS,ATL,HTML,JScript,Qt
Mobile App Development Tools X-Code 3.2/4.0, Titanium. ADT, MS Silverlight 4, Expression Blend
Project Management Dot project, MS Project, Mind manager 6 pro, net office.
Software Architecture Rational rose, Design for databases, Erwin modeler, MS Visio 2003
Quality Assurance Testog, PVCS tracker, Requisite pro, Mantus BT
Configuration & Content Mgmt. Subversion, CVS, VSS, Git, SharePoint, Mambo Server, Wordpress, Durpal
Databases / RDBMS Mysql, Postgres, Oracle, MSSQL, MS Access, SQLite
Server Administration Win server, SUSE Linux, Apache / IIS, postfix, openxpki, samba, privoxy
Reporting Tools Crystal Reports 8.5, Microsoft SQL server reporting Services. CERTIFICATIONS / WORKSHOPS
CERTIFICATIONS YEAR INSTITUTION DETAILS
QMR certification 2005 Softech worldwide L.L.C (USA) Quality Management Rep.
Quality Auditing 2005 Pakistan Institute of Quality Control ISO 9001:200
Brainbench Certifications 2001 Brainbench Corporation, 14425 Penrose Place, Suite VC Transcript ID: 2574319 MS Visual C++, ASP, MS Visual 150, Chantilly, VA 20151, U.S.A. VB Transcript ID: 2574319 Basic ASP Transcript ID: 2574319
Microsoft Certified System 1999 Microsoft Certified System Engineer, training at SSUET Network Admin, IIS , Tech. Engineer Support, Internetworking,
Microsoft Certified 1998 Microsoft Corporation, Redmond, WA 98052-6399, MS Win Server Professional U.S.A. MCP ID: 1270382
AutoCAD certification 1993 Computer Guide Institute Release 10
WORKSHOPS YEAR INSTITUTION DETAILS
Performance & Load Testing 2009 NUST – SEECS, Islamabad School of Electrical Engineering & Computer Science, NUST,17-1-2009 Network Security 2008 Networkers Society of Pak Sheraton Hotel, Karachi, 7-10-2008.
Microsoft PDC 2007 Microsoft – Pakistan SQL server 2008 AWARD / RECOGNITION / TRAININGS
AWARD/RECOGNITION YEAR INSTITUTION DETAILS URL Revised Embedded OS in 2011 Prentice Hall – USA Acknowledged by Dr. William Stallings in book Operating Systems book by ISBN-10: 013230998X preface (7th Edition). Dr. William ISBN-13: 9780132309981 (Embedded OS : TinyOS & ECOS)
AlphaPeeler - packaged with 2010 Prentice Hall – USA Author of book Dr. William Stallings included this Cryptography & Network Developed at SSUET, Karachi – educational tool in his book of cryptography 5th Security book Pakistan Edition.
NBP Excellence Award 2007 National Bank of Pakistan Awarded on meritorious achievements.
Certification for Professional 2000 Pakistan Engineering Council. Reg. # COMP/1343 Engineer
SOFTEC 98 Award 1998 FAST – ICS, Lahore Implementation of DesignoCAD
PROCOM 98 Award 1998 FAST – ICS, Karachi Implementation of DesignoCAD
AlphaPeeler – Classical 1998- Developed at SSUET - Karachi Most popular educational crypto tool cryptography tool 2011 http://alphapeeler.sourceforge.net
TEACHING/TRAINING YEAR ORGANIZATION DETAILS URL Documentation, Linux 2010 Ministry of Defense- Islamabad Delivered training for employees Decision Making, 360 2008 The Shams Group (Shams Software Conducted internal training: Decision Making, Employee Evaluations Services) – USA. 360° evaluations. Req. Elicitation, RN, Coding 2006 Plexus PVT. LTD. - Karachi SDLC, Development standards & secure coding Standards techniques & tips PHP, Linux, MySQL 2005 Softech Worldwide LLC - USA open-source technology trainings System Programming
Introduction to Unix
Chapter One Introduction to Unix 5 Recommended Course Textbooks
Jerry Peek, Grace Todino, and John Strang , Learning the Unix Operating System Fifth Edition
Deborah S.Ray, Eric J.Ray, UNIX and Linux (Learn UNIX and Linux the quick and easy way) 4th Edition
J. Purcell, Linux Complete Command Reference, By RED HAT SOFTWARE, INC. 1st Edition S. G. Kochan, P. Wood (2003) Unix Shell Programming, 3rd Edition, Sams, 460 p. R. K. Michael (2003) Mastering UNIX Shell Scripting, Wiley, 680 p. W. R. Stevens, S. A. Rago (2005) Advanced Programming in the Unix environment, 2nd Edition, Addison Wesley, 960 p. K. A. Robbins, S. Robbins (1996) Practical Unix Programming, Prentice Hall, 658 p.
Chapter One Introduction to Unix 6 What is Unix?
A modern computer operating system Operating system
―a program that acts as an intermediary between a user of the computer and the computer hardware‖
Software that manages your computer’s resources (files, programs, disks, network, …)
Examples: Windows, MacOS, Solaris, BSD, Linux (e.g. OpenSUSE, Red Hat, Slackware) Modern
Stable, flexible, configurable, allows multiple users and programs
Chapter One Introduction to Unix 7 What is Unix?
Unix is a multi-user, multi-tasking operating system. You can have many users logged into a system simultaneously, each running many programs. It's the kernel's job to keep each process and user separate and to regulate access to system hardware, including cpu, memory, disk and other I/O devices.
Chapter One Introduction to Unix 8 Why Unix?
Used in many scientific and industrial settings Huge number of free and well-written software programs Open-source operating system (OS) Excellent programming environment Largely hardware-independent Based on standards Internet servers and services run on Unix
Roughly 65% of the world’s web servers are Linux/Unix machines running Apache
Chapter One Introduction to Unix 9 Brief History of Unix
First Version was created in Bell Labs in 1969. Some of the Bell Labs programmers who had worked on this project, Ken Thompson, Dennis Ritchie, Rudd Canaday, and Doug McIlroy designed and implemented the first version of the Unix File System on a PDP-7 along with a few utilities. It was given the name UNIX by Brian Kernighan. 00:00:00 Hours, Jan 1, 1970 is time zero for UNIX. It is also called as epoch.
Chapter One Introduction to Unix 10 Brief History of Unix
Ken Thompson & Dennis Richie originally developed the earliest versions of Unix at Bell Labs for internal use in 1970s
Simple and elegant
Borrowed best ideas from other OSs
Meant for programmers and computer experts
Meant to run on ―mini computers‖
Chapter One Introduction to Unix 11 Early Unix History
Thompson also rewrote the operating system in high level language of his own design which he called B. The B language lacked many features and Ritchie decided to design a successor to B which he called C. They then rewrote Unix in the C programming language to aid in portability.
Small portion written in assembly language (kernel)
Remaining code written in C on top of the kernel
Chapter One Introduction to Unix 12 Unix History
Multics 1965 First Edition 1971 (AT&T) (CACM 1974, 365-375) 1BSD 1977 (Berkeley) Sixth Edition 1975 (AT&T) 4BSD 1980 (Berkeley) SunOS 1985 (Sun) System V 1985 (AT&T) Tenth Edition 1989 (AT&T) 4.3BSD Net/2 1991 (Berkeley) First Linux kernel 1992 (Linus) Solaris 1993 (Sun) FreeBSD-1.0 1993 NetBSD-1.0 1994 OpenBSD-2.0 1996 Max OS X 10.1 2001 (Apple)
Chapter One Introduction to Unix 13 Unix versions
Two main threads of development:
Berkeley software distribution (BSD) (http://www.bsd.org)
Unix System Laboratories (http://www.unix.org)
BSD
SunOS 4, Ultrix, BSDI, OS X, NetBSD, FreeBSD, OpenBSD, Linux (GNU)
SYS V
System V (AT&T -> Novell -> SCO), Solaris (SunOS 5), HP-UX (Hewlett-Packard), AIX
Chapter One Introduction to Unix 14 Brief History of Linux
Andrew Tanenbaum, a Dutch professor developed MINIX to teach the inner workings of operating systems to his students
In 1991 at the University of Helsinki, Linus Torvalds, inspired by Richard Stallman’s GNU free software project and the knowledge presented in Tanenbaum’s operating system, created Linux, an open-source, Unix-based operating system
Over the last decade, the effort of thousands of open- source developers has resulted in the establishment of Linux as a stable, functional operating system
Chapter One Introduction to Unix 15 Linux
Linux is a free Unix-type operating system originally created by Linus Torvalds with the assistance of developers around the world. It originated in 1991 as a personal project of Linus Torvalds, a Finnish graduate student. The Kernel version 1.0 was released in 1994 and today the most recent stable version is 2.6.9 Developed under the GNU General Public License , the source code for Linux is freely available to everyone.
Chapter One Introduction to Unix 16 Layers in a Unix-based System
User Interface
Users Library interface Standard Utility Programs (shell, editors, compilers, etc.) System interface calls User Mode Standard Library (open, close read, write, etc.) Unix Operating System (process management, memory management, Kernel Mode file system, I/O, etc.) Hardware (CPU, memory, disks, terminals, etc.)
Chapter One Introduction to Unix 17 Unix Structure
The kernel is the core of the Unix operating system, controlling the system hardware and performing various low-level functions. Other parts of a Unix system (including user programs) call on the kernel to perform services for them. The shell accepts user commands and is responsible for seeing that they are carried out.
Chapter One Introduction to Unix 18 Unix Structure (cont.)
Over four hundred utility programs or tools are supplied with the Unix system. These utilities (or commands) support a variety of tasks such as copying files, editing text, performing calculations, and developing software. This course will introduce a limited number of these utilities or tools, focusing on those that aid in software development.
Chapter One Introduction to Unix 19 Getting started
Chapter One Introduction to Unix 20 The Unix Account
Logging in to a Unix machine requires an account on that system. A user account is associated with login and password. ―login‖ is your user name (usually some variant of your real name) Your password will not echo as you type Remember good password practices
Chapter One Introduction to Unix 21 Logging into a UNIX system init (Process ID 1 created by the kernel at bootstrap) spawns getty for every terminal device getty opens terminal device, sets file descriptors 0, 1, 2 to it, waits for a user name, usually sets some environment variable (TERM) invokes login when user name entered login reads password entry (getpwnam()), asks for user’s password (getpass()) and validates it; changes ownership of our terminal device, changes to our UID and changes to our home directory. Sets additional environment variables (HOME, SHEL, USER, LOGNAME, PATH) invokes our login shell
Login shell (bash)
Chapter One Introduction to Unix 22 Logging into a UNIX system
bootstrap : The ROM routine used to load the OS is often known as
getty, short for "get teletype", is a Unix program running on a host computer that manages physical or virtual terminals (tty). When it detects a connection, it prompts for a username and runs the 'login' program to authenticate the user. getty is usually called by init.
One getty process serves one terminal. In some systems, for example Solaris, getty was replaced by ttymon.
Chapter One Introduction to Unix 23 Logging into a UNIX system
init (short for initialization) is a daemon process that is the ancestor of all other processes. Init is the first process started during booting, and is typically assigned PID number 1. It is started by the kernel using a hard-coded filename, and if the kernel is unable to start it, a kernel panic will result. Init continues running until the system is shut down.
Bash is a Unix shell written by Brian Fox for the GNU Project as a free softwarereplacement for the Bourne shell (sh).[3][4] Released in 1989,[5] it has been distributed widely as the shell for the GNU operating system and as the default shell on Linux and Mac OS X. It has been ported to Microsoft Windows and distributed with Cygwin and MinGW, to DOS by the DJGPP project, to Novell NetWare and to Android via various terminal emulation applications.
Chapter One Introduction to Unix 24 Bash
Chapter One Introduction to Unix 25 Logging into a UNIX system
Bash is a POSIX shell but with a number of extensions.
The Bourne shell (sh) was the default Unix shell of Unix Version 7. Most Unix-like systems continue to have /bin/sh— which will be the Bourne shell, or a symbolic link orhard link to a compatible shell—even when other shells are used by most users.
Developed by Stephen Bourne at AT&T Bell Laboratories, it was a replacement for theThompson shell, whose executable file had the same name—sh. It was released in 1977 in the Version 7 Unix release distributed to colleges and universities. Although it is used as an interactive command interpreter, it was always intended as a scripting language and contains all the features that are commonly considered to produce structured programs.
Chapter One Introduction to Unix 26 Logging into a UNIX system
POSIX ( /ˈpɒzɪks/ POZ-iks), an acronym for "Portable Operating System Interface ", is a family of standards specified by the IEEE for maintaining compatibility between operating systems. POSIX defines the application programming interface (API), along with command line shells and utility interfaces, for software compatibility with variants
Chapterof OneUnix and otherIntroduction operating to Unix systems 27 How Logins were processed
init (using /etc/ttys or /etc/inittab) -> forks and execs getty programs on each terminal getty gets user name -> execs login
login verifies password -> execs login shell
User uses login shell
Login methods: Using an X display
User logins in via getty/login, then runs startx
xdm -- reads username & passwd, starts X as that user
Somewhat like a startx without the login shell
Can start a "terminal" (or shell) window
Chapter One Introduction to Unix 28 Secure Login Tools
Terminal connection
PuTTy (on Windows)
MindTerm (Java applet)
Desktop connection
X-Win32
CDE, KDE, GNOME
WeirdX (Java application)
File transfer
WinSCP3
SmartFTP
Chapter One Introduction to Unix 29 What is a Shell?
Just a Unix program executed when you log in A command interpreter provides the basic user interface to UNIX utilities A programming language program consisting of shell commands is called a shell script you can put commands in a file and execute it:
First, make the file executable (chmod u+x script−file)
Lines starting with # are comments Make use of interpreter files (kernel feature!): the first line of your script file must begin with a line: #!pathname optional−arguments where pathname is an absolute pathname (typically /bin/sh, or /bin/bash) of the interpreter.
Chapter One Introduction to Unix 30 The Shell Prompt
After logging in, some information about the system will be displayed, followed by a shell prompt, where commands may be entered
$
%
#
username@hostname>
hostname %
Chapter One Introduction to Unix 31 The Shell
The shell is the program you use to send commands to the Unix system
Some commands are a single word
who
date
ls
Others use additional information
cat textfile
ls -l
Chapter One Introduction to Unix 32 Command Syntax
Commands must be entered exactly. If you make a mistake before entering, delete/backspace to fix it. Be careful!
command options argument(s)
Options modify a command’s execution
Arguments indicate upon what a command should act (often filenames)
Chapter One Introduction to Unix 33 Example Commands: ls (list)
ls –l
ls –a
ls –la
ls –a; ls –l
ls -F
ls –al textfile1
ls –al textfile1 textfile2
ls –al directory
Chapter One Introduction to Unix 34 -l long format, displaying Unix file types, permissions, number of hard links, owner, group, size, date, and filename
-F appends a character revealing the nature of a file, for example, * for an executable, or / for a directory. Regular files have no suffix.
-a lists all files in the given directory, including those whose names start with "." (which are hidden files in Unix). By default, these files are excluded from the list.
-R recursively lists subdirectories. The command ls -R / would therefore list all files.
-d shows information about a symbolic link or directory, rather than about the link's target or listing the contents of a directory.
-t sort the list of files by modification time.
-h print sizes in human readable format. (e.g., 1K, 234M, 2G,
Chapteretc.) One Introduction to Unix 35 Sample usage : ls
The following example demonstrates the output of the ls command given two different arguments: $ pwd /home/fred $ ls -l drwxr--r-- 1 fred editors 4096 drafts -rw-r--r-- 1 fred editors 30405 edition-32 -r-xr-xr-x 1 fred fred 8460 edit $ ls -F drafts/ edition-32 edit*(x)
Chapter One Introduction to Unix 36 In this example, the user fred has a directory named drafts, a regular file called edition-32, and an executable named edit in his home directory. ls uses unix file permission notation to indicate which users or groups are allowed to access each file or directory.
drwxr--r-- 1 fred editors 4096 Mar 1 2007 drafts This means that the letters behind the file descriptor (d), which indicates a folder or 'directory', list three characters to indicate permissions for the current user (rwx), then the group to which the file belongs (r--), and the rights of others (r--).
'drafts' is a directory (d), the user has the right to read (r) write (w) and execute (x): rwx, group members have (r--), meaning read only, and others have (r--), meaning read only access.
Chapter One Introduction to Unix 37 Command Execution
The current shell (bash) executes built-in commands (echo, kill, pwd, …) or shell scripts invoked by the . (dot) command: . shell-script calls fork() to create a new shell process
sub-shell (bash) The sub-shell executes a shell script or calls exec() to execute a command or program terminates after script or command execution During command execution, the parent either waits, or continues if command is executed in the background
Chapter One Introduction to Unix 38 No Shell Prompt
If you don’t get a prompt
A program is probably running
If you see a special program prompt, try to quit the program (quit, bye, exit)
If you see nothing, you can
Stop the program with CTRL-Z (program will wait until started again)
Interrupt the program with CTRL-C (program will usually die)
Chapter One Introduction to Unix 39 Logging Out
Always log out when you are done
Use the exit command to log out of a shell (sometimes logout or CTRL-D)
Note: if you are running in a windowing environment, logging out of the shell only ends that shell. You must also log out of the windowing, typically selecting an option from a menu.
Chapter One Introduction to Unix 40