Preface

The Modular Debugger (MDB) is a highly extensible, general purpose debugging tool for the Solaris^TM Operating System. The Solaris Modular Debugger Guide describes how to use MDB to debug complex software systems, with a particular emphasis on the facilities available for debugging the Solaris kernel and associated device drivers and modules. It also includes a complete reference for and discussion of the MDB language syntax, debugger features, and MDB Module Programming API.

Note –

This Solaris release supports systems that use the SPARC® and x86 families of processor architectures: UltraSPARC®, SPARC64, AMD64, Pentium, and Xeon EM64T. The supported systems appear in the Solaris OS Hardware Compatibility Lists at http://www.sun.com/bigadmin/hcl. This document cites any implementation differences between the platform types.

In this document the term “x86” refers to 64-bit and 32-bit systems manufactured using processors compatible with the AMD64 or Intel Xeon/Pentium product families. For supported systems, see the Solaris OS Hardware Compatibility Lists.

Who Should Use This Book

If you were a detective and were investigating at the scene of a crime, you might interview the witnesses and ask them to describe what happened and who they saw. However, if there were no witnesses or these descriptions proved insufficient, you might consider collecting fingerprints and forensic evidence that could be examined for DNA to help solve the case. Often, software program failures divide into analogous categories: problems that can be solved with source-level debugging tools, and problems that require low-level debugging facilities, examination of core files, and knowledge of assembly language to diagnose and correct. MDB is a debugger designed to facilitate analysis of this second class of problems.

It might not be necessary to use MDB in every case, just as a detective doesn't need a microscope and DNA evidence to solve every crime. However, when programming a complex low-level software system such as an operating system, these situations can occur frequently. As a result, MDB is designed as a debugging framework that allows you to construct your own custom analysis tools to aid in the diagnosis of these problems. MDB also provides a powerful set of built-in commands that allow you to analyze the state of your program at the assembly language level.

If you are not familiar with assembly language programming and debugging, Related Books and Papers provides references to materials that you might find useful.

You should also disassemble various functions of interest in the programs you will be debugging in order to familiarize yourself with the relationship between your program's source code and the corresponding assembly language code. If you are planning to use MDB for debugging Solaris kernel software, you should read carefully Chapter 8, Kernel Debugging Modules and Chapter 9, Debugging With the Kernel Memory Allocator. These chapters provide more detailed information on the MDB commands and facilities provided for debugging Solaris kernel software.

How This Book Is Organized

Chapter 1, Modular Debugger Overview provides an overview of the debugger. This chapter is intended for all users.

Chapter 2, Debugger Concepts describes the MDB architecture and explains the terminology for the debugger concepts used throughout this book. This chapter is intended for all users.

Chapter 3, Language Syntax describes the syntax, operators and evaluation rules for the MDB language. This chapter is intended for all users.

Chapter 4, Interaction describes the MDB interactive command-line editing facilities and output pager. This chapter is intended for all users.

Chapter 5, Built-in Commands describes the set of built-in debugger commands that are always available. This chapter is intended for all users.

Chapter 6, Execution Control describes the MDB facilities for controlling the execution of live running programs. This chapter is intended for application developers and device driver developers. Execution control features might also be useful for system administrators.

Chapter 7, Kernel Execution Control describes the MDB facilities for controlling the execution of the live operating system kernel that are specific to kmdb. This chapter is intended for operating system kernel developers and device driver developers.

Chapter 8, Kernel Debugging Modules describes the set of loadable debugger commands that are provided for debugging the Solaris kernel. This chapter is intended for users who intend to examine Solaris kernel crash dumps and for kernel software developers.

Chapter 9, Debugging With the Kernel Memory Allocator describes the debugging features of the Solaris kernel memory allocator and the MDB commands provided to take advantage of these features. This chapter is intended for advanced programmers and kernel software developers.

Chapter 10, Module Programming API describes the facilities for writing loadable debugger modules. This chapter is intended for advanced programmers and software developers who intend to develop custom debugging support for MDB.

Appendix A, Options provides a reference for MDB command-line options.

Appendix B, Notes provides warnings and notes about using the debugger.

Appendix C, Transition From adb and kadb provides a reference for adb commands and their MDB equivalents. The adb command is implemented by mdb.

Appendix D, Transition From crash provides a reference for crash commands and their MDB equivalents. The crash command is no longer present in Solaris.

Related Books and Papers

These books and papers are recommended and related to the tasks that you need to perform:

Vahalia, Uresh. UNIX Internals: The New Frontiers. Prentice Hall, 1996. ISBN 0-13-101908-2
Mauro, Jim and McDougall, Richard. Solaris Internals: Core Kernel Components. Sun Microsystems Press, 2001. ISBN 0-13-022496-0
The SPARC Architecture Manual, Version 9. Prentice Hall, 1998. ISBN 0–13–099227–5
The SPARC Architecture Manual, Version 8. Prentice Hall, 1994. ISBN 0-13-825001-4
Pentium Pro Family Developer's Manual, Volumes 1-3. Intel Corporation, 1996. ISBN 1-55512-259-0 (Volume 1) , ISBN 1-55512-260-4 (Volume 2) , ISBN 1-55512-261-2 (Volume 3)
Bonwick, Jeff. The Slab Allocator: An Object-Caching Kernel Memory Allocator. Proceedings of the Summer 1994 Usenix Conference, 1994. ISBN 9–99–452010–5
SPARC Assembly Language Reference Manual. Sun Microsystems, 1998.
x86 Assembly Language Reference Manual. Sun Microsystems, 1998.
Writing Device Drivers. Sun Microsystems, 2000.
STREAMS Programming Guide. Sun Microsystems, 2000.
Solaris 64-bit Developer’s Guide. Sun Microsystems, 2000.
Linker and Libraries Guide. Sun Microsystems, 2000.

Accessing Sun Documentation Online

The docs.sun.com^SM Web site enables you to access Sun technical documentation online. You can browse the docs.sun.com archive or search for a specific book title or subject. The URL is http://docs.sun.com.

What Typographic Conventions Mean

The following table describes the typographic changes used in this book.

Table P–1 Typographic Conventions


Typeface or Symbol	Meaning	Example
`AaBbCc123`	The names of commands, files, and directories; on-screen computer output	Edit your `.login` file. Use `ls -a`to list all files. `machine_name% you have mail.`
`AaBbCc123`	What you type, contrasted with on-screen computer output	`machine_name%` `su` `Password:`
`AaBbCc123`	Command-line placeholder: replace with a real name or value	To delete a file, type `rm` `filename`.
AaBbCc123	Book titles, new words, or terms, or words to be emphasized.	Read Chapter 6 in User's Guide. These are called class options. You must be root to do this.

Shell Prompts in Command Examples

The following table shows the default system prompt and superuser prompt for the C shell, Bourne shell, and Korn shell, as well as the MDB debugger prompt.

Table P–2 Shell Prompts


Shell	Prompt
C shell prompt	`machine_name%`
C shell superuser prompt	`machine_name#`
Bourne shell and Korn shell prompt	`$`
Bourne shell and Korn shell superuser prompt	`#`
`mdb` prompt	`>`
`kmdb` prompt	[`cpu`]>