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HP OpenVMS System Services Reference Manual
$ENQW
Queues a lock on a resource. The $ENQW service completes synchronously;
that is, it returns to the caller when the lock has been either granted
or converted. For asynchronous completion, use the Enqueue Lock Request
($ENQ) service; $ENQ returns to the caller after queuing the lock
request, without waiting for the lock to be either granted or
converted. In all other respects, $ENQW is identical to $ENQ. See the
$ENQ description for all other information about the $ENQW service.
For additional information about system service completion, see the
Synchronize ($SYNCH) service documentation.
The $ENQ, $ENQW, $DEQ, and $GETLKI services together provide the user
interface to the Lock Management facility.
On Alpha and I64 systems, this service accepts 64-bit addresses.
Format
SYS$ENQW [efn] ,lkmode ,lksb ,[flags] ,[resnam] ,[parid] ,[astadr]
,[astprm] ,[blkast] ,[acmode] ,[rsdm_id]
C Prototype
int sys$enqw (unsigned int efn, unsigned int lkmode, struct _lksb
*lksb, unsigned int flags, void *resnam, unsigned int parid, void
(*astadr)(__unknown_params), unsigned __int64 astprm, void
(*blkast)(__unknown_params), unsigned int acmode, unsigned int
rsdm_id,...);
$ENTER
The Enter service inserts a file name in a directory.
Refer to the OpenVMS Record Management Services Reference Manual for additional information about this
service.
$ERAPAT
Generates a security erase pattern.
Format
SYS$ERAPAT [type] ,[count] ,[patadr]
C Prototype
int sys$erapat (int type, unsigned int count, unsigned int *patadr);
Arguments
type
| OpenVMS usage: |
longword_unsigned |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Type of storage to be written over with the erase pattern. The
type argument is a longword containing the type of
storage.
The three storage types, together with their symbolic names, are
defined by the $ERADEF macro and are listed in the following table:
| Storage Type |
Symbolic Name |
|
Main memory
|
ERA$K_MEMORY
|
|
Disk
|
ERA$K_DISK
|
|
Tape
|
ERA$K_TAPE
|
count
| OpenVMS usage: |
longword_unsigned |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Number of times that $ERAPAT has been called in a single security erase
operation. The count argument is a longword containing
the iteration count.
You should call the $ERAPAT service initially with the
count argument set to 1, the second time with the
count argument set to 2, and so on, until the status
code SS$_NOTRAN is returned.
patadr
| OpenVMS usage: |
longword_unsigned |
| type: |
longword (unsigned) |
| access: |
write only |
| mechanism: |
by reference |
Security erase pattern to be written. The patadr
argument is the address of a longword into which the security erase
pattern is to be written.
Description
The Get Security Erase Pattern service generates a security erase
pattern that can be written into memory areas containing outdated but
sensitive data to make it unreadable. This service is used primarily by
the operating system, but it can also be used by users who want to
perform security erase operations on foreign disks.
You should call the $ERAPAT service iteratively until the completion
status SS$_NOTRAN is returned.
The following example demonstrates how to use the $ERAPAT service to
perform a security erase to a disk. Note that, after each call to
$ERAPAT, a test for the status SS$_NOTRAN is made. If SS$_NOTRAN has
not been returned, $QIO is called to write the pattern returned by
$ERAPAT onto the disk. After this write, $ERAPAT is called again and
the cycle is repeated until the code SS$_NOTRAN is returned, at which
point the security erase procedure is complete.
; Code fragment that erases 20 blocks (blocks 15 through 34) on a disk
;
PATTERN:
.LONG 0 ; Cell to contain output from $ERAPAT
CHANNEL:
.WORD 0 ; Channel assigned to disk device
DEVICE: .ASCID /DISK:/ ; Disk device name
.
.
.
$ASSIGN_S DEVNAM=DISK,- ; Assign a channel to the device
CHAN=CHANNEL
BLBC RO, EXIT ; Branch if error
.
.
.
MOVL #1, R2 ; Set initial count
$ERADEF ; Macro to define names
; used by $ERAPAT
10$: $ERAPAT_S - ; Call the $ERAPAT service
COUNT=R2,-
TYPE=#ERA$K_DISK,-
PATADR=PATTERN
BLBC R0, EXIT ; Branch if error
CMPL #SS$_NOTRAN, R0 ; Are we done?
BEQL EXIT ; Branch if so
$QIO_S CHAN=CHANNEL,-
FUNC=#I0$_WRITELBLK!IO$M_ERASE,- ; Call
P1=PATTERN,- ; to the $QIO service
P2=#<20*512>,- ; to write the erase
P3=#15 ; pattern
INCL R2 ; Increase count
BRB 10$
EXIT: .
.
.
|
Required Access or Privileges
None.
Required Quota
None.
Related Services
$ADD_HOLDER, $ADD_IDENT, $ASCTOID, $CHECK_ACCESS, $CHKPRO, $CREATE_RDB,
$FIND_HELD, $FIND_HOLDER, $FINISH_RDB, $FORMAT_ACL, $FORMAT_AUDIT,
$GET_SECURITY, $GRANTID, $HASH_PASSWORD, $IDTOASC, $MOD_HOLDER,
$MOD_IDENT, $MTACCESS, $PARSE_ACL, $REM_HOLDER, $REM_IDENT, $REVOKID,
$SET_SECURITY
Condition Values Returned
|
SS$_NORMAL
|
The service completed successfully; proceed with the next erase step.
|
|
SS$_NOTRAN
|
The service completed successfully; security erase completed.
|
|
SS$_ACCVIO
|
The
patadr argument cannot be written by the caller.
|
|
SS$_BADPARAM
|
The
type argument or
count argument is invalid.
|
$ERASE
The Erase service deletes a disk file and removes the file's directory
entry specified in the path to the file. If additional directory
entries have been created for this file by the Enter service, you must
use the Remove service to delete them.
Refer to the OpenVMS Record Management Services Reference Manual for additional information about this
service.
$EXIT
Initiates image rundown when the current image in a process completes
execution. Control normally returns to the command interpreter.
Format
SYS$EXIT [code]
C Prototype
int sys$exit (unsigned int code);
Argument
code
| OpenVMS usage: |
cond_value |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Longword value to be saved in the process header as the completion
status of the current image. If you do not specify this argument in a
macro call, a value of 1 is passed as the completion code for VAX MACRO
and VAX BLISS--32, and a value of 0 is passed for other languages. You
can test this value at the command level to provide conditional command
execution.
Description
The $EXIT service is unlike all other system services in that it does
not return status codes in R0 or anywhere else. The $EXIT service does
not return control to the caller; it performs an exit to the command
interpreter or causes the process to terminate if no command
interpreter is present.
Required Access or Privileges
None
Required Quota
None
Related Services
$CANEXH, $CREPRC, $DCLEXH, $DELPRC, $FORCEX, $GETJPI, $GETJPIW, $HIBER,
$PROCESS_SCAN, $RESUME, $SETPRI, $SETPRN, $SETPRV, $SETRWM, $SUSPND,
$WAKE
$EXPREG
Adds a specified number of new virtual pages to a process's program
region or control region for the execution of the current image.
Expansion occurs at the current end of that region's virtual address
space.
Format
SYS$EXPREG pagcnt ,[retadr] ,[acmode] ,[region]
C Prototype
int sys$expreg (unsigned int pagcnt, struct _va_range *retadr, unsigned
int acmode, char region);
Arguments
pagcnt
| OpenVMS usage: |
longword_unsigned |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Number of pages (on VAX systems) or pagelets (on Alpha and I64 systems)
to add to the current end of the program or control region. The
pagcnt argument is a longword value containing this
number.
On Alpha and I64 systems, the specified value is rounded up to an even
multiple of the CPU-specific page size.
retadr
| OpenVMS usage: |
address_range |
| type: |
longword (unsigned) |
| access: |
write only |
| mechanism: |
by reference |
Starting and ending process virtual addresses of the pages that $EXPREG
has actually added. The retadr argument is the address
of a 2-longword array containing, in order, the starting and ending
process virtual addresses.
acmode
| OpenVMS usage: |
access_mode |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Access mode to be associated with the newly added pages. The
acmode argument is a longword containing the access
mode.
The most privileged access mode used is the access mode of the caller.
The newly added pages are given the following protection: (1) read and
write access for access modes equal to or more privileged than the
access mode used in the call, and (2) no access for access modes less
privileged than that used in the call.
region
| OpenVMS usage: |
longword_unsigned |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Number specifying which program region is to be expanded. The
region argument is a longword value. A value of 0 (the
default) specifies that the program region (P0 region) is to be
expanded. A value of 1 specifies that the control region (P1 region) is
to be expanded.
Description
The Expand Program/Control Region service adds a specified number of
new virtual pages to a process's program region or control region for
the execution of the current image. Expansion occurs at the current end
of that region's virtual address space.
The new pages, which were previously inaccessible to the process, are
created as demand-zero pages.
Because the bottom of the user stack is normally located at the end of
the control region, expanding the control region is equivalent to
expanding the user stack. The effect is to increase the available stack
space by the specified amount.
The starting address returned is always the first available page in the
designated region; therefore, the ending address is smaller than the
starting address when the control region is expanded and is larger than
the starting address when the program region is expanded.
If an error occurs while pages are being added, the
retadr argument (if specified) indicates the pages
that were successfully added before the error occurred. If no pages
were added, both longwords of the retadr argument
contain the value --1.
Required Access or Privileges
None
Required Quota
The process's paging file quota (PGFLQUOTA) must be sufficient to
accommodate the increased size of the virtual address space.
Related Services
$ADJSTK, $ADJWSL, $CRETVA, $CRMPSC, $DELTVA, $DGBLSC, $LCKPAG, $LKWSET,
$MGBLSC, $PURGWS, $SETPRT, $SETSTK, $SETSWM, $ULKPAG, $ULWSET, $UPDSEC,
$UPDSECW
Typically, the information returned in the location addressed by the
retadr argument (if specified) can be used as the
input range to the Delete Virtual Address Space ($DELTVA) service.
Condition Values Returned
|
SS$_NORMAL
|
The service completed successfully.
|
|
SS$_ACCVIO
|
The return address array cannot be written by the caller.
|
|
SS$_EXQUOTA
|
The process exceeded its paging file quota.
|
|
SS$_ILLPAGCNT
|
The specified page count was less than 1 or would cause the program or
control region to exceed its maximum size.
|
|
SS$_INSFWSL
|
The process's working set limit is not large enough to accommodate the
increased virtual address space.
|
|
SS$_VASFULL
|
The process's virtual address space is full. No space is available in
the process page table for the requested regions.
|
$EXPREG_64 (Alpha and I64)
On Alpha and I64 systems, adds a specified number of demand-zero
allocation pages to a process's virtual address space for the execution
of the current image. Expansion occurs at the next free available
address within the specified region.
This service accepts 64-bit addresses.
Format
SYS$EXPREG_64 region_id_64 ,length_64 ,acmode ,flags ,return_va_64
,return_length_64
C Prototype
int sys$expreg_64 (struct _generic_64 *region_id_64, unsigned __int64
length_64, unsigned int acmode, unsigned int flags, void
*(*(return_va_64)), unsigned __int64 *return_length_64);
Arguments
region_id_64
| OpenVMS usage: |
region identifier |
| type: |
quadword (unsigned) |
| access: |
read only |
| mechanism: |
by 32- or 64-bit reference |
The region ID associated with the virtual address range to be expanded.
The file VADEF.H in SYS$STARLET_C.TLB and the $VADEF macro in
STARLET.MLB define a symbolic name for each of the three default
regions in P0, P1, and P2 space.
The following region IDs are defined:
| Symbol |
Region |
|
VA$C_P0
|
Program region
|
|
VA$C_P1
|
Control region
|
|
VA$C_P2
|
64-bit program region
|
Other region IDs, as returned by the $CREATE_REGION_64 service, can be
specified.
length_64
| OpenVMS usage: |
byte count |
| type: |
quadword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Length of the virtual address space to be created. The length specified
must be a multiple of CPU-specific pages.
acmode
| OpenVMS usage: |
access_mode |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Access mode associated with the call to $EXPREG_64. The access mode
determines the owner mode of the pages as well as the read and write
protection on the pages. The acmode argument is a
longword containing the access mode. The $PSLDEF macro defines symbols
for the four access modes.
The $EXPREG_64 service uses whichever of the following two access modes
is least privileged:
- The access mode specified by the acmode argument.
- The access mode of the caller. The protection of the pages is
read/write for the resultant access mode and those more privileged.
Address space cannot be created within a region that has a create mode
associated with it that is more privileged than the caller's mode. The
condition value SS$_IVACMODE is returned if the caller is less
privileged than the create mode for the region.
flags
| OpenVMS usage: |
mask_longword |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Flag mask controlling the characteristics of the demand-zero pages
created. The flags argument is a longword bit vector
in which each bit corresponds to a flag. The $VADEF macro and the
VADEF.H file define a symbolic name for each flag. You construct the
flags argument by performing a logical OR operation on
the symbol names for all desired flags.
All bits in the flags argument are reserved for future
use by HP and should be specified as 0. The condition value SS$_IVVAFLG
is returned if any bits are set.
return_va_64
| OpenVMS usage: |
address |
| type: |
quadword address |
| access: |
write only |
| mechanism: |
by 32- or 64-bit reference |
The lowest process virtual address of a created virtual address range.
The return_va_64 argument is the 32- or 64-bit virtual
address of a naturally aligned quadword into which the service returns
the virtual address.
return_length_64
| OpenVMS usage: |
byte count |
| type: |
quadword (unsigned) |
| access: |
write only |
| mechanism: |
by 32- or 64-bit reference |
The 32- or 64-bit virtual address of a naturally aligned quadword into
which the service returns the length in bytes of the virtual address
range created.
Description
The Expand Virtual Address Space service is a kernel mode service that
can be called from any mode. This service adds a range of demand-zero
allocation pages to a process's virtual address space for the execution
of the current image. Expansion occurs at the next free available
address within the specified region. The new pages, which were
previously inaccessible to the process, are created as demand-zero
pages.
The returned address is always the lowest virtual address in the range
of pages created. The returned length is always an unsigned byte count
indicating the length of the range of pages created.
Successful return status from $EXPREG_64 Expand Virtual Address service
means that the specified region's virtual address space was expanded by
the number of bytes specified in the length_64
argument.
If the condition value SS$_ACCVIO is returned by this service, a value
cannot be returned in the memory locations pointed to by the
return_va_64 and return_length_64
arguments. If a condition value other than SS$_ACCVIO is returned, the
returned address and returned length indicate the pages that were
successfully added before the error occurred. If no pages were added,
the return_va_64 argument will contain the value --1,
and a value cannot be returned in the memory location pointed
to by the return_length_64 argument.
Required Privileges
None
Required Quota
The working set quota (WSQUOTA) of the process must be sufficient to
accommodate the increased length of the process page table required by
the increase in virtual address space.
The process's paging file quota (PGFLQUOTA) must be sufficient to
accommodate the increased size of the virtual address space.
Related Services
$CREATE_BUFOBJ_64, $CREATE_REGION_64, $CRETVA_64, $DELETE_REGION_64,
$DELTVA_64, $LCKPAG_64, $LKWSET_64, $PURGE_WS, $SETPRT_64, $ULKPAG_64,
$ULWSET_64
Condition Values Returned
|
SS$_NORMAL
|
The service completed successfully.
|
|
SS$_ACCVIO
|
The
return_va_64 argument or the
return_length_64 argument cannot be written by the
caller.
|
|
SS$_EXPGFLQUOTA
|
The process exceeded its paging file quota.
|
|
SS$_INSFWSL
|
The process's working set limit is not large enough to accommodate the
increased virtual address space.
|
|
SS$_IVACMODE
|
The caller's mode is less privileged than the create mode associated
with the region.
|
|
SS$_IVREGID
|
An invalid region ID was specified.
|
|
SS$_IVVAFLG
|
An invalid flag, a reserved flag, or an invalid combination of flags
and arguments was specified.
|
|
SS$_LEN_NOTPAGMULT
|
The
length_64 argument is not a multiple of CPU-specific
pages.
|
|
SS$_NOSHPTS
|
The region ID of a shared page table region was specified.
|
|
SS$_REGISFULL
|
The specified virtual region is full.
|
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