HP OpenVMS Systems Documentation

HP OpenVMS System Services Reference Manual

On Alpha and I64 systems, allows a process to map a section of its address space to a specified portion of a file. This service creates and maps a private disk file section.

This service accepts 64-bit addresses.

Format

SYS$CRMPSC_FILE_64 region_id_64 ,file_offset_64 ,length_64 ,chan ,acmode ,flags ,return_va_64 ,return_length_64 [,fault_cluster [,start_va_64]]

C Prototype

int sys$crmpsc_file_64 (struct _generic_64 *region_id_64, unsigned __int64 file_offset_64, unsigned __int64 length_64, unsigned short int chan, 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 region to map the private disk file section. 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.

file_offset_64

OpenVMS usage:	byte offset
type:	quadword (unsigned)
access:	read only
mechanism:	by value

Byte offset into the file that marks the beginning of the section. The file_offset_64 argument is a quadword containing this number. If you specify the file_offset_64 argument as 0, the section is created beginning with the first byte in the file.

The file_offset_64 argument must be a multiple of virtual disk blocks.

length_64

OpenVMS usage:	byte count
type:	quadword (unsigned)
access:	read only
mechanism:	value

Length, in bytes, of the private disk file section to be created and mapped to. The length specified must be 0 or a multiple of virtual disk blocks. If the length specified is 0 or extends beyond end-of-file (EOF), the disk file is mapped up to and including the virtual block number that contains EOF.

chan

OpenVMS usage:	longword
type:	longword (unsigned)
access:	read only
mechanism:	by value

Number of the channel on which the file has been accessed. The chan argument is a longword containing this number. The access mode at which the channel was opened must be equal to or less privileged than the access mode of the caller.

Use the OpenVMS Record Management Services (RMS) macro $OPEN to access a file; the file options parameter in the file access block must indicate a user file open (UFO) keyword.

acmode

OpenVMS usage:	access_mode
type:	longword (unsigned)
access:	read only
mechanism:	by value

Access mode that is to be the owner of the pages created during the mapping. The acmode argument is a longword containing the access mode.

The $PSLDEF macro in STARLET.MLB and the file PSLDEF.H in SYS$STARLET_C.TLB define the following symbols and their values for the four access modes:

Value	Symbolic Name	Access Mode
0	PSL$C_KERNEL	Kernel
1	PSL$C_EXEC	Executive
2	PSL$C_SUPER	Supervisor
3	PSL$C_USER	User

The most privileged access mode used is the access mode of the caller. The calling process can delete pages only if those pages are owned by an access mode equal to or less privileged than the access mode of the calling process.

flags

OpenVMS usage:	mask_longword
type:	longword (unsigned)
access:	read only
mechanism:	by value

Flag mask specifying the characteristics of the private section to be created. The flags argument is a longword bit vector in which each bit corresponds to a flag. The $SECDEF macro and the SECDEF.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.

The following table describes each flag that is valid for the $CRMPSC_FILE_64 service:

Flag	Description
SEC$M_CRF	Pages are copy-on-reference.
SEC$M_DZRO	Pages are demand-zero pages. By default, they are not zeroed when copied. Note that SEC$M_DZRO and SEC$M_CRF cannot both be set and that SEC$M_DZRO set and SEC$M_WRT clear is an invalid combination.
SEC$M_EXPREG	Pages are mapped into the first available space at the current end of the specified region.
SEC$M_NO_OVERMAP	Pages cannot overmap existing address space. By default, pages can overmap existing address space.
SEC$M_WRT	Pages form a read/write section. By default, pages form a read-only section.

All other bits in the flags argument are reserved for future use by HP and should be specified as 0. The condition value SS$_IVSECFLG is returned if any undefined bits are set or if an illegal combination of flags is 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 into which the private disk file section was mapped. 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 of the usable virtual address range mapped in bytes. This length might differ from the total amount mapped. If the section being mapped does not completely fill the last page used to map the section, the return_va_64 and return_length_64 arguments indicate the highest address that actually maps the section.

fault_cluster

OpenVMS usage:	byte count
type:	longword (unsigned)
access:	read only
mechanism:	by value

Page fault cluster in byte units indicating how many pages are to be brought into memory when a page fault occurs for a single page. The fault cluster specified will be rounded up to a multiple of CPU-specific pages.

If this argument is specified as 0, the process default page fault cluster will be used. If this argument is specified as more than the maximum allowed for the system, no condition value will be returned. The systemwide maximum will be used.

start_va_64

OpenVMS usage:	address
type:	quadword address
access:	read only
mechanism:	by value

The starting virtual address to map the private disk file section. The specified virtual address must be a CPU-specific page aligned address. If the flag SEC$M_EXPREG is specified, the start_va_64 argument must not be specified or must be specified as 0. If SEC$M_EXPREG is set and the start_va_64 argument is nonzero, the condition value SS$_IVSECFLG is returned.

Description

The Create and Map Private Disk File Section service allows a process to create a map to a private disk file section. Creating a private disk file section involves mapping all or part of a disk file as a section. The section is mapped from a low address to a high address whether the section is mapped in a region that grows from low to high addresses or from high to low addresses.

The flag SEC$M_WRT applies only to the way in which the newly created section is mapped. For a file to be made writable, the channel used to open the file must allow write access to the file.

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 mapped before the error occurred. If no pages were mapped, 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 must have sufficient byte count quota to satisfy the request.

If the section pages are copy-on-reference, the process must have sufficient paging file quota (PGFLQUOTA).

Related Services

$CREATE_REGION_64, $CRMPSC, $CRMPSC_GFILE_64, $CRMPSC_GPFILE_64, $CRMPSC_GPFN_64, $CRMPSC_PFN_64, $DELETE_REGION_64, $DELTVA_64, $LCKPAG_64, $LKWSET_64, $PURGE_WS, $SETPRT_64, $ULKPAG_64, $ULWSET_64, $UPDSEC_64, $UPDSEC_64W

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$_CHANVIO	The specified channel was assigned from a more privileged access mode.
SS$_ENDOFFILE	The file_offset_64 argument specified is beyond the logical end-of-file.
SS$_EXBYTLM	The process has exceeded the byte count quota; the system was unable to map the requested file.
SS$_EXPGFLQUOTA	The process exceeded its paging file quota.
SS$_INSFWSL	The process's working set limit is not large enough to accommodate the increased virtual address space.
SS$_IVCHAN	An invalid channel number was specified; the channel number specified was 0 or a channel that is unassigned.
SS$_IVCHNLSEC	The channel number specified is currently active, or there are no files opened on the specified channel.
SS$_IVIDENT	An invalid channel number was specified; the channel number specified is larger than the number of channels available.
SS$_IVLOGNAM	The specified global section name has a length of 0 or has more than 43 characters.
SS$_IVREGID	Invalid region ID specified.
SS$_IVSECFLG	An invalid flag, a reserved flag, or an invalid combination of flags and arguments was specified.
SS$_LEN_NOTBLKMULT	The length_64 argument is not a multiple of virtual disk blocks.
SS$_NOSHPTS	A virtual address within a shared page table region was specified.
SS$_NOTFILEDEV	The device is not a file-oriented, random-access, or directory device.
SS$_OFF_NOTBLKALGN	The file_offset_64 argument is not a multiple of virtual disk blocks.
SS$_NOWRT	The file is read-only, the flag bit SEC$M_WRT was set, and the flag bit SEC$M_CRF is not set.
SS$_PAGNOTINREG	A page in the specified range is not within the specified region.
SS$_PAGOWNVIO	A page in the specified range already exists and cannot be deleted because it is owned by a more privileged access mode than that of the caller.
SS$_REGISFULL	The specified virtual region is full; no space is available in the region for the pages created to contain the mapped section.
SS$_VA_IN_USE	A page in the specified input address range is already mapped and the flag SEC$M_NO_OVERMAP is set, or the existing underlying page cannot be deleted because it is associated with a buffer object.
SS$_VA_NOTPAGALGN	The start_va_64 argument is not CPU-specific page aligned.

On Alpha and I64 systems, allows a process to create a memory-resident global demand-zero section and to map a section of its address space to the global section. Shared page table sections can also be created.

This service accepts 64-bit addresses.

Format

SYS$CRMPSC_GDZRO_64 gs_name_64 ,ident_64 ,prot ,length_64 ,region_id_64 ,section_offset_64 ,acmode ,flags ,return_va_64 ,return_length_64 [[[[,start_va_64] ,map_length_64] ,reserved_length_64] ,rad_mask]

C Prototype

int sys$crmpsc_gdzro_64 (void *gs_nam_64, struct _secid *ident_64, unsigned int prot, unsigned __int64 length_64, struct _generic_64 *region_id_64, unsigned __int64 section_offset_64, unsigned int acmode, unsigned int flags, void *(*(return_va_64)), unsigned __int64 *return_length_64,...);

Arguments

gs_name_64

OpenVMS usage:	section_name
type:	character-coded text string
access:	read only
mechanism:	by 32- or 64-bit descriptor--fixed-length string descriptor

Name of the global section. The gs_name_64 argument is the 32- or 64-bit virtual address of a naturally aligned 32- or 64-bit string descriptor pointing to this name string.

ident_64

OpenVMS usage:	section_id
type:	quadword (unsigned)
access:	read only
mechanism:	by 32- or 64-bit reference

Identification value specifying the version number of a global section. The ident_64 argument is a quadword containing three fields. The ident_64 argument is the 32- or 64-bit virtual address of a naturally aligned quadword that contains the identification value.

The first longword specifies the matching criteria in its low-order 2 bits. The valid values, symbolic names by which they can be specified, and their meanings are as follows:

Value	Symbolic Name	Match Criteria
0	SEC$K_MATALL	Match all versions of the section.
1	SEC$K_MATEQU	Match only if major and minor identifications match.
2	SEC$K_MATLEQ	Match if the major identifications are equal and the minor identification of the mapper is less than or equal to the minor identification of the global section.

When a section is mapped at creation time, the match control field is ignored. If you specify the ident_64 argument as 0, the version number and match control fields default to 0.

The version number is in the second longword. The version number contains two fields: a minor identification in the low-order 24 bits and a major identification in the high-order 8 bits. You can assign values for these fields by installation convention to differentiate versions of global sections. If no version number is specified when a section is created, processes that specify a version number when mapping cannot access the global section.

prot

OpenVMS usage:	file_protection
type:	longword (unsigned)
access:	read only
mechanism:	by value

Protection to be applied to the global demand-zero section. The mask contains four 4-bit fields. Bits are read from right to left in each field. The following diagram depicts the mask:

Cleared bits indicate that read, write, execute, and delete access, in that order, are granted to the particular category of user. Only read, write, and execute access are meaningful for section protection. Delete access bits are ignored. Read access also grants execute access for those situations where execute access applies. If zero is specified, read access and write access are granted to all users.

length_64

region_id_64

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:

Other region IDs, as returned by the $CREATE_REGION_64 service, can be specified.

section_offset_64

If a shared page table region is specified by the region_id_64 argument, section_offset_64 must be an even multiple of the number of bytes that can be mapped by a CPU-specific page table page.

acmode

If the memory-resident global section is created with shared page tables, this is the access mode that is stored in the owner, read, and write fields of the corresponding shared page table entries (PTEs).

The $PSLDEF macro in STARLET.MLB and the file PSLDEF.H in SYS$STARLET_C.TLB define the following symbols and their values for the four access modes:

The most privileged access mode used is the access mode of the caller. The calling process can delete pages only if those pages are owned by an access mode equal to or less privileged than the access mode of the calling process.

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

The following table describes each flag that is valid for the $CRMPSC_GDZRO_64 service: