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HP OpenVMS System Analysis Tools Manual
MODIFY DUMP
Allows a given byte, word, longword, or quadword in the dump file to be
modified.
Format
MODIFY DUMP {/BLOCK=n/OFFSET=n|/NEXT}
[/CONFIRM=n] {/BYTE|/WORD|/LONGWORD (d)|/QUADWORD} value
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.
/CONFIRM=n
Checks existing contents of location to be modified.
/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.
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.
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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
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Examples
| #1 |
SDA>> MODIFY DUMP/BLOCK=10/OFFSET=100/WORD FF
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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
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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
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This example shows the dump file modified with a word value of 00FF at
offset 100 in block 00000010 replaced by 0000.
READ
Loads the global symbols contained in the specified file into the SDA
symbol table.
Format
READ [/[NO]LOG|/RELOCATE
=expression|/SYMVA=expression]
{/EXECUTIVE
[directory spec]|/FORCE filespec
|/IMAGE filespec|filespec}
Parameters
directory-spec
Name of the directory containing the loadable images of the executive.
This parameter defaults to SDA$READ_DIR, which is a search list of
SYS$LOADABLE_IMAGES and SYS$LIBRARY.
filespec
Name of the device, directory, and file that contains the file from
which you want to read global symbols. The filespec
defaults to SYS$DISK:[default-dir]filename.type, where SYS$DISK and
[default-dir] represent the disk and directory specified in your last
DCL command SET DEFAULT. If no type has been given in
filespec, SDA first tries .STB and then .EXE.
If no device or directory is given in the file specification, and the
file specification is not found in SYS$DISK:[default_dir], then SDA
attempts to open the file SDA$READ_DIR:filename.type. If no type has
been given in filespec, SDA first tries .STB and then
.EXE.
If the file name is the same as that of an execlet or image, but the
symbols in the file are not those of the execlet or image, then you
must use the /FORCE qualifier, and optionally /RELOCATE and /SYMVA
qualifiers, to tell SDA how to interpret the symbols in the file.
The READ command accepts quoted filenames for access to images on ODS-5
disks with lowercase or compound characters in their names.
Qualifiers
/EXECUTIVE directory-spec
Reads into the SDA symbol table all global symbols and global entry
points defined within all loadable images that make up the executive.
For all the execlets in the system, SDA reads the .STB or .EXE files in
the requested directory.
/FORCE filespec
Forces SDA to read the symbols file, regardless of what other
information or qualifiers are specified. If you do not specify the
/FORCE qualifier, SDA may not read the symbols file if the specified
filespec matches the image name in either the
executive loaded images or the current processes activated image list,
and one of the following conditions is true:
- The image has a symbols vector (is a shareable image), and a
symbols vector was not specified with the /SYMVA or /IMAGE qualifier.
- The image is sliced, and slicing information was not provided with
the /IMAGE qualifier.
- The shareable or executive image is not loaded at the same address
it was linked at, and the relocation information was not provided with
either the /IMAGE or /RELOCATE qualifier.
The use of /FORCE [/SYMVA=addr][/RELOCATE=addr]
filespec is a variant of the /IMAGE qualifier and
avoids fixing up the symbols to match an image of the same name.
/IMAGE filespec
Searches the executive loaded image list and the current process
activated image list for the image specified by
filespec. If the image is found, the symbols are read
in using the image symbol vector (if there is one) and either slicing
or relocation information.
This is the preferred way to read in the .STB files produced by the
linker. These .STB files contain all universal symbols, unless
SYMBOL_TABLE=GLOBAL is in the linker options file, in which case the
.STB file contains all universal and global symbols.
/LOG
/NOLOG (D)
The /LOG qualifier causes SDA to output the %SDA-I-READSYM message for
each symbol table file it reads. You can specify the /LOG qualifier
with any other combination of parameters and qualifiers.
The /NOLOG qualifier suppresses the output of the %SDA-I-READSYM
messages. This is the default. You can specify the /NOLOG qualifier
with any other combination of parameters and qualifiers.
/RELOCATE=expression
Changes the relative addresses of the symbols to absolute addresses by
adding the value of expression to the value of each
symbol in the symbol table file to be read. This qualifier changes
those addresses to absolute addresses in the address space into which
the dump is mapped.
The relocation only applies to symbols with the relocate flag set. All
universal symbols must be found in the symbol vector for the image. All
constants are read in without any relocation.
If the image is sliced (image sections are placed in memory at
different relative offsets than how the image is linked), then the
/RELOCATE qualifier does not work. SDA compares the file name used as a
parameter to the READ command against all the image names in the
executive loaded image list and the current processes activated image
list. If a match is found, and that image contains a symbol vector, an
error results. At this point you can either use the /FORCE qualifier or
the /IMAGE qualifier to override the error.
/SYMVA=expression
Informs SDA whether the absolute symbol vector address is for a
shareable image (SYS$PUBLIC_VECTORS.EXE) or base system image
(SYS$BASE_IMAGE.EXE). All symbols found in the file with the universal
flag are found by referencing the symbol vector (that is, the symbol
value is a symbol vector offset).
Description
The READ command symbolically identifies locations in memory and the
definitions used by SDA for which the default files
(SDA$READ_DIR:SYS$BASE_IMAGE.EXE and SDA$READ_DIR:REQSYSDEF.STB)
provide no definition. In other words, the required global symbols are
located in modules and symbol tables that have been compiled and/or
linked separately from the executive. SDA extracts no local symbols
from the files.
The file specified in the READ command can be the output of a compiler
or assembler (for example, an .OBJ file).
Note
The READ command can read both OpenVMS Alpha and OpenVMS I64 format
files. Do not use READ to read files that contain symbols specific to
another architecture, as this might change the behavior of other SDA
commands for the current architecture.
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Most often the file is provided in SYS$LOADABLE_IMAGES. Many SDA
applications, for instance, need to load the definitions of system data
structures by issuing a READ command specifying SYSDEF.STB. Others
require the definitions of specific global entry points within the
executive image.
The files in SYS$LOADABLE_IMAGES define global locations within
executive images, including those listed in Table 4-1. The actual
list of executive images used varies, depending on platform type,
devices, and the settings of several system parameters.
Table 4-1 Modules Defining Global Locations Within Executive Images
| File |
Contents |
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ACME.EXE
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$ACM system service
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CNX$DEBUG.EXE
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Connection Manager trace routines
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DDIF$RMS_EXTENSION.EXE
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Support for Digital Document Interchange Format (DDIF) file operations
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ERRORLOG.STB
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Error-logging routines and system services
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EXCEPTION.STB
1
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Bugcheck and exception-handling routines and those system services that
declare condition and exit handlers
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EXEC_INIT.STB
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Initialization code
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F11BXQP.STB
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File system support
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FC$GLOGALS.STB
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Fibrechannel symbols
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IMAGE_MANAGEMENT.STB
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Image activator and the related system services
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IO_ROUTINES.STB
1
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$QIO system service, related system services (for example, $CANCEL and
$ASSIGN), and supporting routines
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LAT$RATING.EXE
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CPU load-balancing routines for LAT
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LCK$DEBUG.EXE
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Lock manager trace routines
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LMF$GROUP_TABLE.EXE
4
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Data structures for licensed product groups
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LOCKING.STB
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Lock management routines and system services
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LOGICAL_NAMES.STB
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Logical name routines and system services
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MESSAGE_ROUTINES.STB
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System message routines and system services (including $SNDJBC and
$GETTIM)
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MSCP.EXE
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Disk MSCP server
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MULTIPATH.STB
1
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Fibrechannel multipath support routines
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NET$CSMACD.EXE
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CSMA/CD LAN management module
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NET$FDDI.EXE
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FDDI LAN management module
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NT_EXTENSION.EXE
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NT extensions for persona system services
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PROCESS_MANAGEMENT.STB
1
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Scheduler, report system event, and supporting routines and system
services
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RECOVERY_UNIT_SERVICES.STB
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Recovery unit system services
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RMS.EXE
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Global symbols and entry points for RMS
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SECURITY.STB
1
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Security management routines and system services
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SHELL
xxK.STB
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Process shell
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SPL$DEBUG.EXE
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Spinlock trace routines
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SSPI.EXE
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Security Support Provider Interface
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SYS$
xxDRIVER.EXE
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Run-time device drivers
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SYS$ACPI.EXE
5
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Advanced Configuration and Power Interface routines
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SYS$ATMWORKS351.EXE
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PCI-ATM driver
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SYS$CLUSTER.EXE
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OpenVMS Cluster support routines
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SYS$CPU_ROUTINES_
xxxx.EXE
4
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Processor-specific data and initialization routines
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SYS$EW1000A.EXE
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Gigabit Ethernet driver
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SYS$EW5700.EXE
5
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Gigabit Ethernet driver
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SYS$GALAXY.STB
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OpenVMS Galaxy support routines
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SYS$HWP
nnnn.EXE
5
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PCI support routines
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SYS$IPC_SERVICES.EXE
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Interprocess communication for DECdtm and Batch/Print
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SYS$IPI
nnnn.EXE
5
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PCI support routines
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SYS$LAN.EXE
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Common LAN routines
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SYS$LAN_ATM.EXE
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LAN routines for ATM
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SYS$LAN_ATM4.EXE
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LAN routines for ATM (ForeThought)
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SYS$LAN_CSMACD.EXE
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LAN routines for CSMA/CD
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SYS$LAN_FDDI.EXE
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LAN routines for FDDI
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SYS$LAN_TR.EXE
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LAN routines for Token Ring
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SYS$MME_SERVICES.STB
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Media Management Extensions
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SYS$NETWORK_SERVICES.EXE
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DECnet support
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SYS$NTA.STB
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NT affinity routines and services
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SYS$
xxxx_SUPPORT.EXE
5
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Processor-specific data and initialization routines
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SYS$PUBLIC_VECTORS.EXE
2
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System service vector base image
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SYS$SCS.EXE
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System Communication Services
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SYS$TRANSACTION_SERVICES.EXE
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DECdtm services
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SYS$UTC_SERVICES.EXE
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Universal Coordinated Time services
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SYS$VCC.STB
1,
4
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Virtual I/O cache
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SYS$VM.STB
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System pager and swapper, along with their supporting routines, and
management system services
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SYS$XFCACHE.STB
1
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Extented File Cache
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SYSDEVICE.STB
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Mailbox driver and null driver
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SYSGETSYI.STB
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Get System Information system service ($GETSYI)
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SYSLDR_DYN.STB
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Dynamic executive image loader
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SYSLICENSE.STB
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Licensing system service ($LICENSE)
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SYSTEM_DEBUG.EXE
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XDelta and SCD routines
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SYSTEM_PRIMITIVES.STB
1
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Miscellaneous basic system routines, including those that allocate
system memory, maintain system time, create fork processes, and control
mutex acquisition
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SYSTEM_SYNCHRONIZATION.STB
1
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Routines that enforce synchronization
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TCPIP$BGDRIVER.STB
3
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TCP/IP internet driver
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TCPIP$INETACP.STB
3
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TCP/IP internet ACP
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TCPIP$INETDRIVER.STB
3
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TCP/IP internet driver
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TCPIP$INTERNET_SERVICES.STB
3
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TCP/IP internet execlet
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TCPIP$NFS_SERVICES.STB
3
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Symbols for the TCP/IP NFS server
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TCPIP$PROXY_SERVICES.STB
3
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Symbols for the TCP/IP proxy execlet
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TCPIP$PWIPACP.STB
3
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TCP/IP PWIP ACP
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TCPIP$PWIPDRIVER.STB
3
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TCP/IP PWIP driver
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TCPIP$TNDRIVER.STB
3
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TCP/IP TELNET/RLOGIN server driver
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TMSCP.EXE
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Tape MSCP server
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VMS_EXTENSION.EXE
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VMS extensions for persona system services
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1Variations of these files also exist, for example, where
the file name ends in "_MON." System parameters such as SYSTEM_CHECK
determine which image is loaded.
2This file is located in SYS$LIBRARY.
3Only available if TCP/IP has been installed. These are
found in SYS$SYSTEM, and are not automatically read in when you issue a
READ/EXEC command.
4Alpha only.
5I64 only.
SDA can also read symbols from an image .EXE or .STB produced by the
linker. The STB and EXE files only contain universal symbols. The STB
file, however, can be forced to have global symbols for the image if
you use the SYMBOL_TABLE=GLOBAL option in the linker options file.
A number of ready-built symbol table files ship with OpenVMS. They can
be found in the directory SYS$LOADABLE_IMAGES, and all have names of
the form xyzDEF.STB. Of these files, SDA automatically reads
REQSYSDEF.STB on activation. You can add the symbols in the other files
to SDA's symbol table using the READ command. Table 2-4 lists the
files that OpenVMS provides in SYS$LOADABLE_IMAGES that define data
structure offsets.
The following MACRO program, GLOBALS.MAR, shows how to obtain symbols
in addition to those in SYS$BASE_IMAGE.EXE, other executive images
listed in Table 4-1, and the symbol table files that are listed in
Table 2-4:
.TITLE GLOBALS
; n.b. on following lines GLOBAL must be capitalized
$PHDDEF GLOBAL ; Process header definitions
$DDBDEF GLOBAL ; Device data block
$UCBDEF GLOBAL ; Unit control block
$VCBDEF GLOBAL ; Volume control block
$ACBDEF GLOBAL ; AST control block
$IRPDEF GLOBAL ; I/O request packet
; more can be inserted here
.END
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Use the following command to generate an object module file containing
the globals defined in the program:
$MACRO GLOBALS+SYS$LIBRARY:LIB/LIBRARY /OBJECT=GLOBALS.STB
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Examples
| #1 |
SDA> READ SDA$READ_DIR:SYSDEF.STB/LOG
%SDA-I-READSYM, 10010 symbols read from SYS$COMMON:[SYSEXE]SYSDEF.STB;1
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The READ command causes SDA to add all the global symbols in
SDA$READ_DIR:SYSDEF.STB to the SDA symbol table. Such symbols are
useful when you are formatting an I/O data structure, such as a unit
control block or an I/O request packet.
| #2 |
SDA> SHOW STACK
Process stacks (on CPU 00)
--------------------------
Current operating stack (KERNEL):
00000000.7FF95CD0 FFFFFFFF.80430CE0 SCH$STATE_TO_COM+00040
00000000.7FF95CD8 00000000.00000000
00000000.7FF95CE0 FFFFFFFF.81E9CB04 LNM$SEARCH_ONE_C+000E4
00000000.7FF95CE8 FFFFFFFF.8007A988 PROCESS_MANAGEMENT_NPRO+0E988
SP =>00000000.7FF95CF0 00000000.00000000
00000000.7FF95CF8 00000000.006080C1
00000000.7FF95D00 FFFFFFFF.80501FDC
00000000.7FF95D08 FFFFFFFF.81A5B720
.
.
.
SDA> READ/IMAGE SYS$LOADABLE_IMAGES:PROCESS_MANAGEMENT/LOG
%SDA-I-READSYM, 767 symbols read from SYS$COMMON:[SYS$LDR]PROCESS_MANAGEMENT.STB;1
SDA> SHOW STACK
Process stacks (on CPU 00)
--------------------------
Current operating stack (KERNEL):
00000000.7FF95CD0 FFFFFFFF.80430CE0 SCH$FIND_NEXT_PROC
00000000.7FF95CD8 00000000.00000000
00000000.7FF95CE0 FFFFFFFF.81E9CB04 LNM$SEARCH_ONE_C+000E4
00000000.7FF95CE8 FFFFFFFF.8007A988 SCH$INTERRUPT+00068
SP =>00000000.7FF95CF0 00000000.00000000
00000000.7FF95CF8 00000000.006080C1
00000000.7FF95D00 FFFFFFFF.80501FDC
00000000.7FF95D08 FFFFFFFF.81A5B720
.
.
.
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The initial SHOW STACK command contains an address that SDA resolves
into an offset from the PROCESS_MANAGEMENT executive image. The READ
command loads the corresponding symbols into the SDA symbol table such
that the reissue of the SHOW STACK command subsequently identifies the
same location as an offset within a specific process management routine.
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