| Previous | Contents | Index |
Loads the global symbols contained in the specified file into the SDA symbol table.
READ {/EXECUTIVE [directory spec]
| /FORCE filespec [/RELOCATE =expression | /SYMVA=expression]
| /IMAGE filespec
| filespec}
[ /[NO]LOG]
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, SYS$LIBRARY, and SYS$SYSTEM.filespec
Name of the device, directory, and 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.
/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. By default, these messages are suppressed. You can specify /LOG and /NOLOG 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).
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$READ_DIR:REQSYSDEF.STB) provide no definition. In other words, the required global symbols are located in modules and symbol tables that have been compiled and/or linked separately from the executive. SDA extracts no local symbols from the files.
The file specified in the READ command can be the output of a compiler or assembler (for example, an .OBJ file).
Note
The READ command can read both OpenVMS Alpha and OpenVMS Integrity servers format files. Do not use READ to read files that contain symbols specific to another architecture, as this might change the behavior of other SDA commands for the current architecture.Most often the file is provided in SYS$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 4-2. The actual list of executive images used varies, depending on platform type, devices, and the settings of several system parameters.
Table 4-2 Modules Defining Global Locations Within Executive Images File Contents ACME.EXE $ACM system service CNX$DEBUG.EXE Connection Manager trace routines DDIF$RMS_EXTENSION.EXE Support for Digital Document Interchange Format (DDIF) file operations ERRORLOG.STB Error-logging routines and system services EXCEPTION.STB 1 Bugcheck and exception-handling routines and those system services that declare condition and exit handlers EXEC_INIT.STB Initialization code F11BXQP.STB File system support FC$GLOGALS.STB Fibrechannel symbols IMAGE_MANAGEMENT.STB Image activator and the related system services IO_ROUTINES.STB 1 $QIO system service, related system services (for example, $CANCEL and $ASSIGN), and supporting routines LAT$RATING.EXE CPU load-balancing routines for LAT LCK$DEBUG.EXE Lock manager trace routines LMF$GROUP_TABLE.EXE 4 Data structures for licensed product groups LOCKING.STB Lock management routines and system services LOGICAL_NAMES.STB Logical name routines and system services MESSAGE_ROUTINES.STB System message routines and system services (including $SNDJBC and $GETTIM) MSCP.EXE Disk MSCP server MULTIPATH.STB 1 Fibrechannel multipath support routines NET$CSMACD.EXE CSMA/CD LAN management module NET$FDDI.EXE FDDI LAN management module NT_EXTENSION.EXE NT extensions for persona system services PROCESS_MANAGEMENT.STB 1 Scheduler, report system event, and supporting routines and system services RECOVERY_UNIT_SERVICES.STB Recovery unit system services RMS.EXE Global symbols and entry points for RMS SECURITY.STB 1 Security management routines and system services SHELL xxK.STB Process shell SPL$DEBUG.EXE Spinlock trace routines SSPI.EXE Security Support Provider Interface SYS$ xxDRIVER.EXE Run-time device drivers SYS$ACPI.EXE 5 Advanced Configuration and Power Interface routines SYS$ATMWORKS351.EXE PCI-ATM driver SYS$CLUSTER.EXE OpenVMS Cluster support routines SYS$CPU_ROUTINES_ xxxx.EXE 4 Processor-specific data and initialization routines SYS$EW1000A.EXE Gigabit Ethernet driver SYS$EW5700.EXE 5 Gigabit Ethernet driver SYS$GALAXY.STB OpenVMS Galaxy support routines SYS$HWP nnnn.EXE 5 PCI support routines SYS$IPC_SERVICES.EXE Interprocess communication for DECdtm and Batch/Print SYS$IPI nnnn.EXE 5 PCI support routines SYS$LAN.EXE Common LAN routines SYS$LAN_ATM.EXE LAN routines for ATM SYS$LAN_ATM4.EXE LAN routines for ATM (ForeThought) SYS$LAN_CSMACD.EXE LAN routines for CSMA/CD SYS$LAN_FDDI.EXE LAN routines for FDDI SYS$LAN_TR.EXE LAN routines for Token Ring SYS$MME_SERVICES.STB Media Management Extensions SYS$NETWORK_SERVICES.EXE DECnet support SYS$NTA.STB NT affinity routines and services SYS$ xxxx_SUPPORT.EXE 5 Processor-specific data and initialization routines SYS$PUBLIC_VECTORS.EXE 2 System service vector base image SYS$SCS.EXE System Communication Services SYS$TRANSACTION_SERVICES.EXE DECdtm services SYS$UTC_SERVICES.EXE Universal Coordinated Time services SYS$VCC.STB 1, 4 Virtual I/O cache SYS$VM.STB System pager and swapper, along with their supporting routines, and management system services SYS$XFCACHE.STB 1 Extented File Cache SYSDEVICE.STB Mailbox driver and null driver SYSGETSYI.STB Get System Information system service ($GETSYI) SYSLDR_DYN.STB Dynamic executive image loader SYSLICENSE.STB Licensing system service ($LICENSE) SYSTEM_DEBUG.EXE XDelta and SCD routines SYSTEM_PRIMITIVES.STB 1 Miscellaneous basic system routines, including those that allocate system memory, maintain system time, create fork processes, and control mutex acquisition SYSTEM_SYNCHRONIZATION.STB 1 Routines that enforce synchronization TCPIP$BGDRIVER.STB 3 TCP/IP internet driver TCPIP$INETACP.STB 3 TCP/IP internet ACP TCPIP$INETDRIVER.STB 3 TCP/IP internet driver TCPIP$INTERNET_SERVICES.STB 3 TCP/IP internet execlet TCPIP$NFS_SERVICES.STB 3 Symbols for the TCP/IP NFS server TCPIP$PROXY_SERVICES.STB 3 Symbols for the TCP/IP proxy execlet TCPIP$PWIPACP.STB 3 TCP/IP PWIP ACP TCPIP$PWIPDRIVER.STB 3 TCP/IP PWIP driver TCPIP$TNDRIVER.STB 3 TCP/IP TELNET/RLOGIN server driver TMSCP.EXE Tape MSCP server VMS_EXTENSION.EXE VMS extensions for persona system services
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$LOADABLE_IMAGES, and all have names of the form xyzDEF.STB. Of these files, SDA automatically reads REQSYSDEF.STB on activation. You can add the symbols in the other files to SDA's symbol table using the READ command. Table 2-5 lists the files that OpenVMS provides in SYS$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 4-2, and the symbol table files that are listed in Table 2-5:
.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 |
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 |
| #1 |
|---|
SDA> READ SDA$READ_DIR:SYSDEF.STB/LOG
%SDA-I-READSYM, 10010 symbols read from SYS$COMMON:[SYSEXE]SYSDEF.STB;1
|
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$INTERRUPT+00068
SP =>00000000.7FF95CF0 00000000.00000000
00000000.7FF95CF8 00000000.006080C1
00000000.7FF95D00 FFFFFFFF.80501FDC
00000000.7FF95D08 FFFFFFFF.81A5B720
.
.
.
|
The initial SHOW STACK command contains an address that SDA resolves into an offset from the PROCESS_MANAGEMENT executive image. The READ command loads the corresponding symbols into the SDA symbol table such that the reissue of the SHOW STACK command subsequently identifies the same location as an offset within a specific process management routine.
Repeats execution of the last command issued. On terminal devices, the KP0 key performs the same function as the REPEAT command with no parameter or qualifier.
REPEAT [count | /UNTIL=condition]
count
Number of times the previous command is to be repeated. The default is a single repeat.
/UNTIL=condition
Defines a condition that terminates the REPEAT command. By default, there is no terminating condition.
The REPEAT command is useful for stepping through a linked list of data structures, or for examining a sequence of memory locations. When used with ANALYZE/SYSTEM, it allows the changing state of a system location or data structure to be monitored.You can also use the REPEAT command to provide a convenient method of either displaying a series of data structures in a linked list or examining a sequence of locations. For example:
FORMAT @IOC$GL_DEVLIST ! Start at first DDB in system FORMAT @. ! Skip to next entry in list <KP0> ! Repeat FORMAT @. command . . .
| #1 |
|---|
SDA> SPAWN CREATE SDATEMP.COM
SEARCH 0:3FFFFFFF 12345678
SET PROCESS/NEXT
^Z
SDA> SET PROCESS NULL
SDA> @SDATEMP
SDA> REPEAT/UNTIL = BADPROC
|
This example demonstrates how to search the address space of each process in a system or dump a given pattern.
| #2 |
|---|
SDA> SPAWN CREATE SDATEMP2.COM
FORMAT CPUDB
SET CPU /NEXT
^Z
SDA> READ SYSDEF
SDA> SET CPU /FIRST
SDA> @SDATEMP2
SDA> REPEAT/UNTIL = BADCPU
|
This example demonstrates how to format the CPU database for every CPU in a dump.
| #3 |
|---|
SDA> SHOW CALL_FRAME
Call Frame Information
----------------------
Stack Frame Procedure Descriptor
Flags: Base Register = FP, Jacket, Native
Procedure Entry: FFFFFFFF.80080CE0 MMG$RETRANGE_C+00180
Return address on stack = FFFFFFFF.8004CF30 EXCEPTION_NPRO+00F30
Registers saved on stack
------------------------
7FF95E80 FFFFFFFF.FFFFFFFD Saved R2
7FF95E88 FFFFFFFF.8042DBC0 Saved R3 EXCEPTION_NPRW+03DC0
7FF95E90 FFFFFFFF.80537240 Saved R4
7FF95E98 00000000.00000000 Saved R5
7FF95EA0 FFFFFFFF.80030960 Saved R6 MMG$IMGRESET_C+00200
7FF95EA8 00000000.7FF95EC0 Saved R7
7FF95EB0 FFFFFFFF.80420E68 Saved R13 MMG$ULKGBLWSL E
7FF95EB8 00000000.7FF95F70 Saved R29
.
.
.
SDA> SHOW CALL_FRAME/NEXT_FRAME
Call Frame Information
----------------------
Stack Frame Procedure Descriptor
Flags: Base Register = FP, Jacket, Native
Procedure Entry: FFFFFFFF.80F018D0 IMAGE_MANAGEMENT_PRO+078D0
Return address on stack = FFFFFFFF.8004CF30 EXCEPTION_NPRO+00F30
Registers saved on stack
------------------------
7FF95F90 FFFFFFFF.FFFFFFFB Saved R2
7FF95F98 FFFFFFFF.8042DBC0 Saved R3 EXCEPTION_ NPRW+03DC0
7FF95FA0 00000000.00000000 Saved R5
7FF95FA8 00000000.7FF95FC0 Saved R7
7FF95FB0 FFFFFFFF.80EF8D20 Saved R13 ERL$DEVINF O+00C20
7FF95FB8 00000000.7FFA0450 Saved R29
.
.
.
SDA> REPEAT
Call Frame Information
----------------------
Stack Frame Procedure Descriptor
Flags: Base Register = FP, Jacket, Native
Procedure Entry: FFFFFFFF.80F016A0 IMAGE_MANAGEMENT_PRO+076A0
Return address on stack = 00000000.7FF2451C
Registers saved on stack
------------------------
7FFA0470 00000000.7FEEA890 Saved R13
7FFA0478 00000000.7FFA0480 Saved R29
.
.
.
|
The first SHOW CALL_FRAME displays the call frame indicated by the current FP value. Because the /NEXT_FRAME qualifier to the instruction displays the call frame indicated by the saved frame in the current call frame, you can use the REPEAT command to repeat the SHOW CALL_FRAME/NEXT_FRAME command and follow a chain of call frames.
Scans a range of memory locations for all occurrences of a specified value or string.
SEARCH [/qualifier] range [=] {expression | string}
range
Location in memory to be searched. A location can be represented by any valid SDA expression. To search a range of locations, use the following syntax:
m:n Range of locations to be searched, from m to n m;n Range of locations to be searched, starting at m and continuing for n bytes You must use either an equals sign or a blank to separate range from expression or string.
expression
Value for which SDA is to search. SDA evaluates the expression and searches the specified range of memory for the resulting value. For a description of SDA expressions, see Section 2.6.1.string
Character sequence for which SDA is to search. If all characters in the sequence are printable characters, the string is enclosed in quotes, for example,
"My_String". If the character sequence contains nonprintable characters, it must be specified as a comma-separated list composed of quoted strings and hexadecimal numbers; for example, ("My_String",0C00,"More") would specify a search for "My_String<NUL><FF>More". Each hexadecimal number can be no more than 8 digits (4 bytes) in length. Nonprintable sequences of more than 4 bytes must be split into multiple hexadecimal numbers. The maximum length of a search string is 127 bytes. Note that the quote character itself cannot be included in a quoted string and must be specified as a hexadecimal number.
/IGNORE_CASE
Specifies that searches for strings are not to be case-specific. (By default, searches look for an exact match.) This qualifier is ignored for value searches./LENGTH={QUADWORD | LONGWORD | WORD | BYTE}
Specifies the size of the expression value that the SEARCH command uses for matching. If you do not specify the /LENGTH qualifier, the SEARCH command uses a longword length by default. This qualifier is ignored for string searches./MASK=n
Allows the SEARCH command finer qranularity in its matches. It compares only the given bits of a byte, word, longword, or quadword. To compare bits when matching, you set the bits in the mask; to ignore bits when matching, you clear the bits in the mask. This qualifier is ignored for string searches./PHYSICAL
Specifies that the addresses used to define the range of locations to be searched are physical addresses./STEPS = {QUADWORD | LONGWORD | WORD | BYTE | value}
Specifies the step factor of the search through the specified memory range. After the SEARCH command has performed the comparison between the value of expression or the given string and memory location, it adds the specified step factor to the address of the memory location. The resulting location is the next location to undergo the comparison. If you do not specify the /STEPS qualifier, the SEARCH command uses a step factor of a longword for value searches, and a step factor of a byte for string searches.
SEARCH displays each location as each value or string is found. If you press Ctrl/T while using the SEARCH command, the system displays how far the search has progressed. The progress display is always output to the terminal even if a SET OUTPUT <file> command has previously been entered.
| #1 |
|---|
SDA> SEARCH GB81F0;500 B41B0000
Searching from FFFFFFFF.800B81F0 to FFFFFFFF.800B86EF in LONGWORD steps for B41B0000...
Match at FFFFFFFF.800B86E4 B41B0000
|
This SEARCH command finds the value B41B0000 in the longword at FFFFFFFF.800B86E4.
| #2 |
|---|
SDA> SEARCH 80000000;200/STEPS=BYTE 82
Searching from FFFFFFFF.80000000 to FFFFFFFF.800001FF in BYTE steps for 00000082...
Match at FFFFFFFF.8000012C 00000082
|
This SEARCH command finds the value 00000082 in the longword at FFFFFFFF.8000012C.
| #3 |
|---|
SDA> SEARCH/LENGTH=WORD 80000000;100 10
Match at FFFFFFFF.80000030 0010
Match at FFFFFFFF.80000040 0010
Match at FFFFFFFF.80000090 0010
Match at FFFFFFFF.800000A0 0010
Match at FFFFFFFF.800000C0 0010
5 matches found
|
This SEARCH command finds the value 0010 in the words at FFFFFFFF.80000030, FFFFFFFF.80000040, FFFFFFFF.80000090, FFFFFFFF.800000A0, FFFFFFFF.800000C0.
| #4 |
|---|
SDA> SEARCH/MASK=FF000000 80000000;40 20000000
Searching from FFFFFFFF.80000000 to FFFFFFFF.8000003F in LONGWORD steps for 20000000...
(Using search mask of FF000000)
Match at FFFFFFFF.80000000 201F0104
Match at FFFFFFFF.80000010 201F0001
2 matches found
|
This SEARCH command finds the value 20 in the upper byte of the longwords at FFFFFFFF.80000000 and FFFFFFFF.80000010, regardless of the contents of the lower 3 bytes.
| #5 |
|---|
|
This example combines quoted strings and hexadecimal values to form a character sequence to be used in a search. Note the order in which the bytes within each hexadecimal number are inserted into the search sequence: the least significant byte of the hexadecimal number is the first byte added to the search sequence.
| Previous | Next | Contents | Index |