AS/400 Machine Level Programming. Table of contents

Transcription

1 AS/400 Machine Level Programming Table of contents Chapter 0: Introduction Why Program at the Machine-Level? 0-1 What is the Machine-Level? Above and Below the MI 0-1 Old MI and New MI Is MI Hard and Arcane? 0-1 What About All Those MI-Instructions? Small Programs or Large Programs 0-2 Why is MI so Secret? Chapter 1: Getting Your Own MI-Compiler MI-Compilers 1-1 Create Program (QPRCRTPG) API Detailed Explanation of Each Parameter (Boring) 1-2 The MI-Compiler Front-End The CRTMIPGM Command 1-7 Hello World MI Functional Reference Manual 1-10 Chapter 2: Data Types and Your First Real MI-Program Data Types 2-1 Character Data Type Numeric Data Types 2-2 Data Names Comments 2-3 Hexadecimal Constants Convert Hexadecimal to Character 2-3 Compile Errors Conditions and Branching 2-4 Labels and Branch Points Short Form of Instructions 2-5 Structured Data Our First "Real" MI-Program 2-7 Chapter 3: Pointers, Pointers, and Pointers Space Data Object 3-1 Setting a Space Pointer Explore Pointers: Materialize Invocation Stack 3-2 Static Storage Method Dealing with Exceptions 3-4 Automatic Storage Allocation Instruction Pointers 3-6 Chapter 4: Arithmetic and Timestamps Timestamps 4-1 Convert Timestamp to Date and Time Converting to a Date 4-2 Complete Program to Show Current Date and Time Leap Seconds 4-4 Higher Resolution in Later Versions i

2 Chapter 5: Calling Other Programs External Program Objects 5-1 Obtaining a System Pointer Initializing a System Pointer 5-1 Resolving a System Pointer Copying a System Pointer 5-2 System Entry Point Table (SEPT) Counterfeiting a Pointer 5-2 Encapsulated Objects The Argument List 5-2 Program Call Example Relative Branch Conditions 5-4 An Optimization The System Entry Point Table 5-5 Chapter 6: RISC Code for Setting a Pointer Set Space Pointer From Pointer 6-1 Documentation About the PowerPC AS/400 RISC PowerPC Machine Architecture 6-1 System Service Tools Dissecting SETSPPFP 6-4 LQ - Load Quadword Instruction and Pointer Tag Bits TXER Instruction 6-5 ORI - OR Immediate Instruction ADDI - Add Immediate Instruction 6-6 RLDICL Instruction Condition Register 6-7 BC - Branch Conditional Instruction BLA - Branch with Link to Absolute Address Instruction 6-8 Link Register Addresses, Segments, Offsets, and SLIC 6-8 LD - Load Doubleword Instruction RLDICR Instruction 6-9 SETTAG Instruction STQ, Store Quadword Instruction 6-10 Final Annotated SETSPPFP Code Chapter 7: Accessing Arbitrary Data in Memory Accessing Arbitrary Data 7-1 Set Space Pointer From Any Pointer Counterfeiting the Pointer 7-1 Accessing Encapsulated Program Code Using the Debugger 7-3 System Domain Objects Going System State 7-5 This Does Not Work on a CISC Box Chapter 8: Getting/Setting File Member Information File Member Information 8-1 File Member Cursors The Member Header 8-1 Converting Dates to Timestamps Must be System State 8-3 Parameters Command CHGMBR and Command Processing Program CHGMBRCL 8-4 Command Processing Program ii

3 The Complete MIMBRINF Program 8-6 Chapter 9: The Work Control Block Table Tasks, Processes, and Jobs 9-1 Job Names Finding Work Control Block Tables 9-1 The Process Communication Object The Master (Root) WCB Table List 9-2 Scanning the WCB Tables Testing if a Pointer is Null 9-3 Searching a Work Control Block Table Scanning WCB for Device Name 9-4 Checking the Job Status Putting It All Together 9-5 Performance A Faster Way of Locating Jobs 9-7 Format of the Job Index Header Format of the Job Index Entry 9-8 Addressing the Job Index Finding Entries in the Job Index 9-9 A Faster Version, MIWCBFND A Brief History of WCBT Problems 9-11 Chapter 10: Internal Sorting, Combsort Sorting Internal Data 10-1 Bubble Sort Combsort 10-2 MI-Version of Combsort Override Program Attribute 10-3 The Sort Double Loop Complete Combsort Code 10-4 Using Instruction Pointers Testing Combsort 10-5 Generating Random Numbers Measuring Processor Time Spent 10-5 Calling Combsort Computing N log2 N 10-6 Compute Mathematical Function with 1 Argument Computing Time Differences 10-7 Simple Numeric Editing The Complete MITSTCMB Test Program 10-8 Performance Results RPG Version of COMBSORT Chapter 11: The Machine State Register Machine State Register (MSR) 11-1 Privilege Level The MFMSR/MTMSRD Instructions 11-2 Running in Supervisor Mode Finding the SLIC Code for Call Program 11-3 Retrieving Machine Registers Getting General-Purpose Registers 11-5 Getting Special-Purpose General-Use Registers STD Instruction 11-7 Getting the Machine State Register The Program State 11-8 iii

4 The Floating Point Bit Chapter 12: Input/Output in MI Using the SEPT A File Compressor/Decompressor 12-1 The User File Control Block How Do We Know This Stuff? 12-2 Setting Library/File/Member Some AS/400-S/38 History 12-3 Control Flags More Control Flags 12-4 The FCMPRS (File Compress) Command Command-Processing Program 12-4 Parameter Block The System Entry Point Table (SEPT) 12-5 Opening a File The Open Data Path 12-7 Data Management Entry Point Table I/O Routines The Data Management Option List The Data Management Control List Filling the Input Area Compressing the Input Write the Compressed Records Getting the System Name Decompressing the Data Compression Ratio The Complete Program Chapter 13: File Conversion and Hashing Minimum File Transformation: COPY 13-1 Generic File Transformer Command Translating the Data From a File 13-3 A GREP-Like Utility A KWIC (KeyWord-In-Context) Version of GREP 13-5 Calculating a File Digest Clearing the File Before Output 13-8 Variable Length Part of the UFCB Blocking Records to Increase I/O Performance 13-8 With/Without Level Check Chapter 14: Password Encryption on the AS/ Password Protected Access 14-1 Password Rules Retrieving the Encrypted Password 14-1 Algorithm for the 1st Encrypted Password Using CIPHER to DES-Encrypt 14-4 Algorithm for the 2nd Encrypted Password Why Seven Characters Instead of Eight? 14-7 The Magic Constant The Compleat MIENCPWD Program 14-8 The Brute-Force Attack Passwords Stored in the Clear! A Password Checking Utility Real Security Chapter 15: Program Validation Value iv

5 The Program Validation Value 15-1 States and Domains Saving/Restoring Programs 15-1 Calculating the Program Validation Value The ILE Program Model 15-2 Our TEST Program Object Header 15-2 Program Header The AS/400 Security Oracle 15-3 Effective Address Translation Page Protection Bits 15-5 Writable Program Header History Log 15-5 Program Version Table Program MICLNPGM to Clean Patch Information and History Log 15-7 Program Maintenance Header Module Table Module Header Module Version Table Procedure Table RISC Instructions Module Constants Primary Associated Space Which Components Go Into the PVV? Diffusion and Confusion Program MIPGMVV Computes the PVV Clearing the History Log on V4R Digitally Signed Objects Chapter 16: User-Defined 5250 Datastream I/O Display Files 16-1 The MIHWORLD Program Data Management Option List 16-3 Data Management Control List Device Control (or Name) Block 16-3 Machine Space Pointers Datastream Format 16-4 Buffer Format Datastream Commands 16-4 Orders Field Control Word 16-7 Field Format Word Screen Attributes 16-8 Explanation of the Magic Constants Chapter 17: A Simple Screen I/O Interface Describing Screen Files 17-1 Item Introducer Logical Attributes 17-2 Cursor Position The Contiguous Data Block 17-3 The MITSTSCR Test Program Command Keys 17-4 The MISCRNIO Screen Handler File control Block and Data Management Entries 17-5 Buffer Formats v

6 Orders 17-7 Command Key Translation Data Content Translation 17-8 Attribute Translation Current Cursor Position 17-8 The Screen Handler Code Open Terminal 17-9 Close Terminal Write to Terminal 17-9 The VERIFY MI-Instruction The XLATE MI-Instruction Calculating Where to Place the Cursor Read from Terminal Format of MDT Input Fields Returned Finding Field With Cursor Chapter 18: (SCV) Supervisor Call Vectored The SCV/RFSCV Instructions 18-1 How Is the SCV Used? The SCV Dispatch Code 18-1 RLDIMI Instruction Tracing and Single-Step Mode 18-3 ADDIS Instruction SCV 10 Handler 18-4 The Blocked Instruction Flag Table Other SCV Calls 18-6 What Did We Learn? Chapter 19: Calculating Archimedes' Constant, Pi An Amazing Formula for Pi 19-1 Computing the Square Root The MIPIPKD Program 19-2 The MIPIFLT Program The Original S/38 Program, MIPIS Chapter 20: Exception Handling Exceptions and Events 20-1 Declaring an Exception Monitor The Exception Identifier 20-2 Searching for Exception Descriptions Materialize an Exception Description 20-2 Modifying an Exception Description Monitoring Exceptions: The MIDECEXC Program 20-3 Exception General and Specific Data Return from Exception 20-5 Signaling Exceptions: The MISIGEXC Program Materialize Invocation Attributes 20-6 Signaling an Exception Various Errors 20-8 Preventing Messages in the Joblog Chapter 21: Walking the ODP Chain The Open Data Path 21-1 Searching Work Control Block Tables The Data Management Communication Object 21-2 The DMQC Root vi

7 The SETSPPO MI-Instruction 21-3 A DMCQ Open Entry Locating the ODPs 21-5 Structure of the ODP The Open Feedback 21-6 The I/O Feedback Data to Collect about an Active File 21-7 The MIODPWLK Program Chapter 22: How to Generate a Truly Random Number What is a Random Number? 22-1 Use of Randomness Bad Seeds 22-1 The Entropy Pool Sources of Entropy 22-2 Timing Information Entropy Pool Format 22-3 The Yield Time Resource Management Data 22-4 Processor Utilization Storage Management Counters 22-5 Main Storage Pool Information Disk Storage Information 22-7 Activity Level Control Data Can We Measure the Amount of Entropy in the Pool? 22-9 Aging the Entropy Pool The Get Entropy Program (MIGETETP) The Internal State Generation of Entropy The Entropy Monitor Program (MIETPMON) Conclusion TCP/IP Flaw Because of Lack of Randomness Chapter 23: Automatic Refresh of Display The Automatic Refresh Problem 23-1 DDS Specification for the Display File ASSUME (Assume) Keyword 23-1 CFnn (Command Function) Keyword KEEP (Keep) Keyword 23-1 OVERLAY (Overlay) Keyword USRDFN (User-Defined) Keyword 23-2 INVITE (Invite) Keyword Invited Devices 23-2 General-Purpose Time-out Program The DDS for the Invited Device 23-3 RPG Versions of the Time-Out Program Call Stack for WRKACTJOB Command 23-4 The QDMACCIN Program Changing the Time-out Value Dynamically 23-6 The MIINVDSP Invited Display Program Automatic Refresh Driver Program MIAUTREF 23-8 The CVTEFN MI-Instruction The ROLLUP / ROLLDOWN Problem Acknowledgements Chapter 24: Editing of Numeric Variables vii

8 The Importance of Editing 24-1 Edit Codes and Edit Words COBOL Pictures 24-1 The EDIT MI-Instruction The Edit Mask 24-2 Parameter Length Conformance Left-Justifying the Number 24-4 Chapter 25: Machine Indexes What is a Machine Index? 25-1 Binary Radix Trees The Index Instructions 25-1 Security Level 40+ Considerations The Search Engine Problem 25-2 Index Object Subtypes Creating the Index 25-2 Reading the File Member Extracting Words 25-6 Inserting an Entry Internal Structure of an Index 25-8 Iterating over All Members of a File Insertion Speed Searching the Index Building a Screen Searching for the Word Chapter 26: The AS/400 Memory Explorer Examining Memory without SST 26-1 Accessing Arbitrary Memory Preserving Tag Bits 26-2 Screen Layout Arrays of Fields 26-3 The Explorer Program (MIEXPLR) The DATA to Show 26-4 Stacking/Unstacking of Addresses Showing the Screen 26-4 Enter: Specifying the Location of the Data Paging Down/Up to See More 26-7 The HOME or PCS Position Look at Memory at Another Address 26-7 Detecting a Pointer The CMPPTRT MI-instruction 26-8 Unstacking to Previous Address Displaying Timestamps 26-9 Disassembling Instructions Exiting the Program Building the Screen Image Determining the Pointer Description Ready-made AS/400 Explorer Chapter 27: Inside a Save File Why Save-Files? 27-1 The Internal Save Format The Dump Space 27-2 Dump Space Management Instructions Checksums 27-2 viii

9 Dump Space Header The Dump Space Data Pages The Dump Descriptor 27-3 Dump Descriptor Catalog Extended Object Information 27-4 Show Object in a Save File, MIOBJSAV Walk Descriptors in Save File, MIWLKSAV 27-7 Modifying a Save File Save File Integrity? NOT 27-9 Single-Level Store? Maybe Not Always "Flushing" a Save File to Disk Changing Module Information, MICHGMOD Save Files for CISC Architecture Chapter 28: Recursion, Entropy, and the End of the World Recursive Procedures 28-1 Summing of Integers Equipartition of Energy 28-2 Distinguishability of Particles "How Many Ways to Distribute 10 Units of Energy among 5 Distinguishable Particles?" 28-3 A Computer Simulation Programming Idioms 28-4 Storage Attributes Calling MIADSUMR 28-5 A Parameter That Is Not a Pointer An Iterative Version, MIADSUMI 28-6 Sample Results (Combinatorial Explosion) Method of Finite Differences 28-8 A Note About the Programs for This Chapter The Tower of Hanoi 28-8 Fibonacci Numbers Chapter 29: Changing Your Machine's Serial Number What Legitimate Reason Can You Have For This? 29-1 A True Horror Story The MATMATR Instruction 29-2 Finding the SCV Function OS/400 is Developed Under UNIX 29-2 Contents of the Data Segment Get the Serial Number 29-3 The HDTA Object System Values 29-5 What Happens at the Next IPL? Place of Manufacture 29-6 The "Software" Serial Number Pure conjecture (Probably Incorrect) 29-6 A Little More History 29-6 Chapter 30: The Advanced Encryption Standard The Need for a New Encryption Standard 30-1 The New Encryption Standard The Rounds 30-1 Copy Bits Logical (CPYBTL) Generated RISC Code for MI-Version 30-3 Generated RISC Code for C-Version Optimized RISC Code for C-Version 30-4 ix

10 C-Version of AES Defining an Encryption Round 30-5 Defining a Decryption Round Key Expansion 30-6 The Encryption/Decryption Process Operating Modes 30-8 Electronic Codebook Mode Cipher Block Chaining Mode 30-9 The File Encryption Program, MIFAES Encryption/Decryption Speed Compiling and Binding the C-Programs The AES C-Program The AESTEST Testprogram Chapter 31: The Object Information Repository Extended Common Object Information 31-1 Work with Object Command (WRKOBJ) The OIR (Object Information Repository) 31-2 Work with OIR (MIWRKOIR) Must be System State 31-5 The Change Object Description API (QLICOBJD) Fields in the OIR 31-5 The MISHWOIR Test Program What is in the Additional OIR Records? Chapter 32: Immune against Check Object Integrity Checking Object Integrity 32-1 Hacking CHKOBJITG? Using CHKOBJITG 32-1 Disowning an Object The User Profile as a Machine Index 32-3 Defense in Depth (The Alter Log) Format of Alter Log Entries 32-4 Clearing the Alter Log How Did We Know the Address of the Alter Log? 32-5 Chapter 33: Analysis of SCV 7, Program Call Program Calls 33-1 Adopted Authority The Program State Attribute 33-1 Generated Code for CALLX Instruction The SCV 7 Dispatch Code 33-2 The #AICAPGM Module Check State Attribute 33-3 Finally Calling the Program Entering the Called Program 33-4 The STDU RISC-Instruction Returning from the Called Program 33-4 Format of the Invocation Stack Frame, ISF Chapter 34: Anatomy of a User Profile The Central Role of a User Profile 34-1 Getting User Profile for a Job Object Specific Header 34-2 Privileged Instruction Bits in User Profile Special Authority Bits in User Profile 34-2 x

11 Object Audit Level User Audit Levels 34-3 A Dangerous Program The Associated Space 34-4 Qualified Values Various User Profile Flags 34-5 Language, Country, and Character Set IDs User Options 34-6 Objects Owned by User Profile Chapter 38: Source and Debug Information ILE Programs and Modules 38-1 OIR-Information for Modules Change Licensed Object Description, QLICOBJD 38-2 Anatomy of a Module The HLL Symbol Table 38-3 View Descriptors Descriptor Types 38-5 No Debug Source Why Make the Symbol Table Inaccessible? 38-5 Changing Source/Debug Information, MICHGMOD The Bound Program 38-8 The BNAS Information Debug Source Information Appendix A: MI-Instructions Quick Reference A-1 MI-Instruction Quick Reference A-1 Computational and Branching Instructions A-1 Pointer/Resolution Instructions A-6 Space Management Instructions A-7 Independent Index Instructions A-7 Authorization Instructions A-7 Program and Invocation Instructions A-8 Exception Management Instructions A-9 Queue Management Instructions A-9 Object Lock Instructions A-10 Context Management Instructions A-10 Heap Management Instructions A-10 Resource Management Instructions A-11 MI Support Functions Instructions A-11 Date/Time/Timestamp Instructions A-11 Appendix B: Object Type/Subtypes B-1 Object Type/Subtypes B-1 Object List B-1 Appendix C: PowerPC Instruction Set Quick Reference C-1 Instructions Sorted by Mnemonic C-1 Appendix D: SEPT Entries in the User Domain D-1 System Entry Point Table Entries D-1 Entries Sorted by Number D-1 Entries Sorted by Name D-13 Appendix E: SCV 10 Function Numbers E-1 Supervisor Call (Vectored) Functions E-1 xi

12 Appendix F: Open and I/O Feedback Areas F-1 Open Feedback Area F-1 I/O Feedback Area F-6 Common I/O Feedback Area F-6 I/O Feedback Area for ICF and Display Files F-8 I/O Feedback Area for Printer Files F-10 I/O Feedback Area for Database Files F-10 xii