HP OpenVMS System Analysis Tools Manual


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HELP

Displays information about the SDA utility, its operation, and the format of its commands.

Format

HELP [topic-name]


Parameter

topic-name

Topic for which you need information. A topic can be an SDA command name such as ATTACH or COPY, the name of an SDA extension such as CLUE or FLT, or a keyword such as Extensions or Process_Context.

If you enter HELP with no topic name, a list of all topics is displayed.


Qualifiers

None.

Description

The HELP command displays brief descriptions of SDA commands and concepts on the terminal screen (or sends these descriptions to the file designated in a SET OUTPUT command). You can request additional information by specifying the name of a topic in response to the Topic? prompt.

If you do not specify a parameter in the HELP command, it lists the features of SDA and those commands and topics for which you can request help, as follows:


Example


SDA> HELP
HELP 
 
 
     The System Dump Analyzer (SDA) allows you to inspect the contents 
     of memory as saved in the dump taken at crash time or as exists 
     in a running system. You can use SDA interactively or in batch 
     mode. You can send the output from SDA to a listing file. You can 
     use SDA to perform the following operations: 
 
                     Assign a value to a symbol 
                     Examine memory of any process 
                     Format instructions and blocks of data 
                     Display device data structures 
                     Display memory management data structures 
                     Display a summary of all processes on the system 
                     Display the SDA symbol table 
                     Copy the system dump file 
                     Read global symbols from any object module 
                     Search memory for a given value 
                     Send output to a file or device 
 
     For help on performing these functions, use the HELP command and 
     specify a topic. 
 
     Format 
 
       HELP  [topic-name] 
 
 
 
  Additional information available: 
 
     . 
     . 
     . 
 
 
Topic?
  
      


MAP

Transforms an address into an offset in a particular image.

Format

MAP address


Parameter

address

Address to be identified.

Qualifiers

None.

Description

The MAP command identifies the image name and offset corresponding to an address. With this information, you can examine the image map to locate the source module and program section offset corresponding to an address.

If the address is in system space, MAP searches for the specified address in executive images first. It then checks activated images in process space to search those images installed using the /RESIDENT qualifier of the Install utility. Finally, it checks all image-resident sections in system space. If the address is in process space, MAP searches the activated images for the process.

If the address cannot be found, MAP displays the following message:


%SDA-E-NOTINIMAGE, Address not within a system/installed image 

On Integrity servers, the MAP command can also provide additional data for addresses in system space. If the address is determined to be in a code section of an executive loaded image or a resident shareable image, and if the image file is accessible and was linked using /TRACEBACK, the traceback data is used to obtain and display the module name and routine name information. See Example 11.


Examples

#1

SDA> MAP G90308
Image                               Base      End       Image Offset
SYS$VM                                 
Nonpaged read only                  80090000  800ABA00  00000308
 
      

Examining the image map identified by this MAP command (SYS$VM.MAP) shows that image offset 308 falls within psect EXEC$HI_USE_PAGEABLE_CODE because the psect goes from offset 0 to offset 45D3:


   .
   .
   .
EXEC$HI_USE_PAGEABLE_CODE       00000000 000045D3 000045D4 ( 17876.) 2 **  5...
                SYSCREDEL       00000000 0000149B 0000149C (  5276.) 2 **  5 
                SYSCRMPSC       000014A0 000045D3 00003134 ( 12596.) 2 **  5 
 
EXEC$NONPAGED_CODE              000045E0 0001B8B3 000172D4 ( 94932.) 2 **  5...
                EXECUTE_FAULT   000045E0 0000483B 0000025C (   604.) 2 **  5 
                IOLOCK          00004840 000052E7 00000AA8 (  2728.) 2 **  5 
                LOCK_SYSTEM_PAGES                      
   .
   .
   .
Specifically, image offset 308 is located within source module SYSCREDEL. Therefore, to locate the corresponding code, you would look in SYSCREDEL for offset 308 in psect EXEC$HI_USE_PAGEABLE_CODE.

#2

SDA> MAP G550000
Image                            Base         End       Image Offset
SYS$DKDRIVER                     80548000     80558000  00008000
      

In this example, the MAP command identifies the address as an offset into an executive image that is not sliced. The base and end addresses are the boundaries of the image.

#3

SDA> MAP G550034
Image                            Base         End       Image Offset
SYS$DUDRIVER
      Nonpaged read/write        80550000     80551400  00008034
      

In this example, the MAP command identifies the address as an offset into an executive image that is sliced. The base and end addresses are the boundaries of the image section that contains the address of interest.

#4

SDA> MAP GF0040 
Image Resident Section           Base         End       Image Offset
MAILSHR                          800F0000     80119000  00000040
      

The MAP command identifies the address as an offset into an image-resident section residing in system space.

#5

SDA> MAP 12000  
Activated Image                  Base         End       Image Offset
MAIL                             00010000     000809FF  00002000
      

The MAP command identifies the address as an offset into an activated image residing in process-private space.

#6

SDA> MAP B2340  
Compressed Data Section          Base         End       Image Offset
LIBRTL                           000B2000     000B6400  00080340
      

The MAP command identifies the address as being within a compressed data section. When an image is installed with the Install utility using the /RESIDENT qualifier, the code sections are mapped in system space. The data sections are compressed into process-private space to reduce null pages or holes in the address space left by the absence of the code section. The SHOW PROCESS/IMAGE=ALL display shows how the data has been compressed; the MAP command searches this information to map an address in a compressed data section to an offset in an image.

#7

SDA> MAP 7FC06000  
Shareable Address Data Section          Base      End       Image Offset
LIBRTL                                  7FC06000  7FC16800  00090000
      

The MAP command identifies the address as an offset into a shareable address data section residing in P1 space.

#8

SDA> MAP 7FC26000
Read-Write Data Section                 Base      End       Image Offset
LIBRTL                                  7FC26000  7FC27000  000B0000
      

The MAP command identifies the address as an offset into a read-write data section residing in P1 space.

#9

SDA> MAP 7FC36000
Shareable Read-Only Data Section        Base      End       Image Offset
LIBRTL                                  7FC36000  7FC3F600  000C0000
      

The MAP command identifies the address as an offset into a shareable read-only data section residing in P1 space.

#10

SDA> MAP 7FC56000
Demand Zero Data Section                Base      End       Image Offset
LIBRTL                                  7FC56000  7FC57000  000E0000
      

The MAP command identifies the address as an offset into a demand zero data section residing in P1 space.

#11

SDA> MAP FFFFFFFF.8042FE00
Image                               Base               End          Image Offset 
EXCEPTION_MON 
    Code                      FFFFFFFF.8041FE00 FFFFFFFF.804E3DFF 00000000.00028000 
 
    Module:     IPF_DECODE + 00005380 
    Routine:    process_i_unit + 00000840 
 
      

This example shows the additional module and routine offset information that is displayed for system space code sections.


MODIFY DUMP

Allows a given byte, word, longword, or quadword in the dump file to be modified.

Format

MODIFY DUMP value {/BLOCK=n/OFFSET=n | /NEXT}
{/BYTE | /WORD | /LONGWORD (d) | /QUADWORD}
[/CONFIRM=n]


Parameter

value

New value deposited in the specified location in the dump file.

Qualifiers

/BLOCK=n

Indicates block number to be modified. Required unless the /NEXT qualifier is given.

/OFFSET=n

Indicates byte offset within block to be modified. Required unless the /NEXT qualifier is given.

/NEXT

Indicates that the byte or bytes immediately following the location altered by the previous MODIFY DUMP command are to be modified. Used instead of the /BLOCK=n and /OFFSET=n qualifiers.

/BYTE

Indicates that only a single byte is to be replaced.

/WORD

Indicates that a word is to be replaced.

/LONGWORD

Indicates that a longword is to be replaced. This is the default.

/QUADWORD

Indicates that a quadword is to be replaced.

/CONFIRM=n

Checks existing contents of location to be modified.

Description

The MODIFY DUMP command is used on a dump file that cannot be analyzed without specifying the /OVERRIDE qualifier on the ANALYZE/CRASH_DUMP command. You can use the MODIFY DUMP command to correct the problem that prevents normal analysis of a dump file. You can only use the MODIFY DUMP command when you have invoked SDA with the ANALYZE/CRASH_DUMP/OVERRIDE command.

Important

This command is not intended for general use. It is provided for the benefit of HP support personnel when investigating crash dumps that cannot be analyzed in other ways.

If the block being modified is part of either the dump header, the error log buffers, or the compression map, the changes made are not seen when you issue the appropriate SHOW DUMP command, unless you first exit from SDA and then reissue the ANALYZE/CRASH_DUMP command.

The MODIFY DUMP command sets a bit in the dump header to indicate that the dump has been modified. Subsequent ANALYZE/CRASH_DUMP commands issued to that file produce the following warning message:


%SDA-W-DUMPMOD, dump has been modified 


Examples

#1

SDA>> MODIFY DUMP/BLOCK=10/OFFSET=100/WORD FF
      

This example shows the dump file modified with the word at offset 100 in block 00000010 replaced by 00FF.

#2

SDA>> MODIFY DUMP/BLOCK=10/OFFSET=100/WORD 0/CONFIRM=EE
%SDA-E-NOMATCH, expected value does not match value in dump; dump not updated 
      

This example shows what happens when the actual word value of 00FF at offset 100 in block 00000010 does not match the given value of 00EE.

#3

SDA>> MODIFY DUMP/BLOCK=10/OFFSET=100/WORD 0/CONFIRM=FF
      

This example shows the dump file modified with a word value of 00FF at offset 100 in block 00000010 replaced by 0000.


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