[an error occurred while processing this directive]

HP OpenVMS Systems Documentation

Content starts here

HP OpenVMS System Services Reference Manual


Previous Contents Index

Setting the prmflg argument to nonzero changes privilege bits in both the CURPRIV mask and the PROCPRIV mask.

prvprv


OpenVMS usage: mask_privileges
type: quadword (unsigned)
access: write only
mechanism: by reference

Privileges previously possessed by the calling process. The prvprv argument is the address of a quadword bit vector wherein each bit corresponds to a privilege that was previously either enabled or disabled. If you do not specify prvprv or assign it the value 0, the previous privilege mask is not returned.

Description

The Set Privileges service enables or disables specified privileges for the calling process.

The operating system maintains four separate privilege masks for each process:

  • AUTHPRIV---Privileges that the process is authorized to enable, as designated by the system manager or the process creator. The AUTHPRIV mask never changes during the life of the process.
  • PROCPRIV---Privileges that are designated as permanently enabled for the process. The PROCPRIV mask can be modified by $SETPRV.
  • IMAGPRIV---Privileges with which the current image is installed.
  • CURPRIV---Privileges that are currently enabled. The CURPRIV mask can be modified by $SETPRV.

When a process is created, its AUTHPRIV, PROCPRIV, and CURPRIV masks have the same contents. Whenever a system service (other than $SETPRV) must check the process privileges, that service checks the CURPRIV mask.

When a process runs an installed image, the privileges with which that image was installed are enabled in the CURPRIV mask. When the installed image exits, the PROCPRIV mask is copied to the CURPRIV mask.

The $SETPRV service can set bits only in the CURPRIV and PROCPRIV mask, but $SETPRV checks the AUTHPRIV mask to see whether a process can set specified privilege bits in the CURPRIV or PROCPRIV masks. Consequently, a process can give itself the SETPRV privilege only if this privilege is enabled in the AUTHPRIV mask.

You can obtain each of a process's four privilege masks by calling the $GETJPI (Get Job/Process Information) service and specifying the desired privilege mask or masks as item codes in the itmlst argument. You construct the item code for a privilege mask by prefixing the name of the privilege mask with the characters JPI$_ (for example, JPI$_CURPRIV is the item code for the current privilege mask).

The DCL command SET PROCESS/PRIVILEGES also enables or disables specified privileges; refer to the HP OpenVMS DCL Dictionary for details.

Required Access or Privileges

To set a privilege permanently, the calling process must be authorized to set the specified privilege, or the process must be executing in kernel or executive mode.

To set a privilege temporarily, one of the following three conditions must be true:

  • The calling process must be authorized to set the specified privilege.
  • The calling process must be executing in kernel or executive mode.
  • The image currently executing must be one that was installed with the specified privilege.

Required Quota

None

Related Services

$CANEXH, $CMKRNL, $CREPRC, $DCLEXH, $DELPRC, $EXIT, $FORCEX, $GETJPI, $GETJPIW, $HIBER, $PROCESS_SCAN, $RESUME, $SETPRI, $SETPRN, $SETRWM, $SUSPND, $WAKE


Condition Values Returned

SS$_NORMAL The service completed successfully. All privileges were enabled or disabled as specified.
SS$_NOTALLPRIV The service completed successfully. Not all specified privileges were enabled; see the Description section for details.
SS$_ACCVIO The privilege mask cannot be read or the previous privilege mask cannot be written by the caller.
SS$_IVSTSFLG You specified a value other than 1 or 0 in either the prmflg argument or the enblfg argument.

$SETRWM

Allows a process to specify what action system services should take when system resources required for their execution are unavailable.

Caution

Disabling resource waiting should be performed with caution, as doing so can have unexpected effects on constituent sharable images and runtime libraries.

Format

SYS$SETRWM [watflg]


C Prototype

int sys$setrwm ( char watflg);


Argument

watflg


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

Indicator specifying whether system services should wait for required resources. The watflg argument is a longword value. The value 0 (the default) specifies that system services should wait until resources needed for their execution become available. The value 1 specifies that system services should return failure status immediately when resources needed for their execution are unavailable.

The operating system enables resource wait mode for all processes. You can disable resource wait mode only by calling $SETRWM.

If resource wait mode is disabled, it remains disabled until it is explicitly reenabled or until the process is deleted.


Description

The Set Resource Wait Mode service allows a process to specify what action system services should take when system resources required for their execution are unavailable.

When resource wait mode is enabled, system services wait for the required system resources to become available and then continue execution. When resource wait mode is disabled, system services return to the caller when required system resources are unavailable. The condition value returned by $SETRWM indicates whether resource wait mode was previously enabled or previously disabled.

The following system resources and process quotas are affected by resource wait mode:

  • System dynamic memory: nonpaged pool, lock manager dynamic memory1
  • UNIBUS adapter map registers
  • Direct I/O limit (DIOLM) quota
  • Buffered I/O limit (BIOLM) quota
  • Buffered I/O byte count limit (BYTLM) quota
  • Timer queue quota
  • Mailbox buffer quota
  • Insufficient pipe quota

Caution

Due to the process-wide implications of resource waiting, disabling resource waiting should be performed with caution.

Disabling resource wait mode can have unexpected effects on libraries or shareable images upon which your application may be directly or indirectly dependent. If resource waiting is disabled, these constituent libraries or shareable images may not perform as expected. It is possible that these constituent components are coded to assume resource waiting is enabled; therefore, they may not be coded to receive various quota-related errors such as SS$_EXQUOTA.

Note that you should have full control over the entire program context down to the system calls before disabling resource wait mode.

Required Access or Privileges

None

Required Quota

None

Related Services

$CANEXH, $CREPRC, $DCLEXH, $DELPRC, $EXIT, $FORCEX, $GETJPI, $GETJPIW, $HIBER, $PROCESS_SCAN, $RESUME, $SETPRI, $SETPRN, $SETPRV, $SUSPND, $WAKE


Condition Values Returned

SS$_WASCLR The service completed successfully. Resource wait mode was previously enabled.
SS$_WASSET The service completed successfully. Resource wait mode was previously disabled.

Note

1 Also, physical memory or system page table entries under rare circumstances.

$SETSHLV

Controls whether a process automatically unshelves files.

Format

SYS$SETSHLV [pidadr] ,[prcnam] ,[shlvflg]


C Prototype

int sys$setshlv (unsigned int *pidadr, void *prcnam, unsigned int shlvflg);


Arguments

pidadr


OpenVMS usage: process_id
type: longword (unsigned)
access: modify
mechanism: by reference

Process identification (PID) of the process. The pidadr argument is the address of the PID. The pidadr argument can only refer to a process running on the local node. You cannot modify a process on a remote node.

You must specify the pidadr argument to modify a process whose UIC group number is different from that of the calling process.

prcnam


OpenVMS usage: process_name
type: character--coded text string
access: read only
mechanism: by descriptor--fixed-length string descriptor

Process name of the process. The prcnam argument is the address of a character string descriptor pointing to the process name. You identify a process with a 1- to 15-character string.

You can only use the prcnam argument to modify a process in the same UIC group as the calling process. To modify a process in another UIC group, you must specify the pidadr argument.

shlvflg


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

Value specifying whether automatic unshelving is to be turned on or off. The shlvflg argument is a longword containing this value. The value 0 turns automatic unshelving on. The value 1 turns automatic unshelving off.

Description

The Set Automatic Unshelving service controls whether a process automatically unshelves files.

The pidadr and prcnam default to the current process. If the longword at address pidadr is 0, the PID of the target process is returned.

The setting for automatic unshelving is inherited by subprocesses.

The DCL command SET PROCESS/[NO]AUTOUNSHELVE also controls automatic unshelving for a process; refer to the HP OpenVMS DCL Dictionary for details.

Required Access or Privileges

Depending on the operation, the calling process might need one of the following privileges to use $SETSHLV:

  • GROUP privilege to modify a process in the same group, unless the target process has the same UIC as the calling process.
  • WORLD privilege to modify any process in the system.

Required Quota

None

Related Services

$GETJPI


Condition Values Returned

SS$_WASCLR The service completed successfully. Automatic unshelving was previously on.
SS$_WASSET The service completed successfully. Automatic unshelving was previously off.
SS$_ACCVIO An argument was not accessible by the caller.
SS$_BADPARAM The shlvflg argument was invalid.
SS$_IVLOGNAM The prcnam argument was invalid. The process name string had either 0 characters or more than 15 characters.
SS$_NONEXPR The specified process did not exist, or the specified process identification was invalid.
SS$_NOPRIV The caller did not have the privilege to modify other processes.
SS$_REMOTE_PROC The specified process was not on the local node. The service cannot modify a process on a remote node.

$SETSTK

Allows a process to change the size of its supervisor, executive, and kernel stacks by altering the values in the stack limit for a memory stack and base arrays held in P1 (per-process) space.

Format

SYS$SETSTK inadr ,[retadr] ,[acmode]


C Prototype

int sys$setstk (struct _va_range *inadr, struct _va_range *retadr, unsigned int acmode);


Arguments

inadr


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

Range of addresses that express the stack's new limits. The inadr argument is the address of a 2-longword array containing, in order, the address of the top of the stack and the address of the base of the stack. Because stacks in P1 space expand from high to low addresses, the address of the base of the stack must be greater than the address of the top of the stack.

retadr


OpenVMS usage: address_range
type: longword (unsigned)
access: write only
mechanism: by reference

Range of addresses that express the stack's previous limits. The retadr argument is the address of a 2-longword array into which $SETSTK writes, in the first longword, the previous address of the top of the stack and, in the second longword, the previous address of the base of the stack.

acmode


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

Access mode of the stack to be altered. The acmode argument is a longword containing the access mode. The $PSLDEF macro defines symbols for the four access modes. The most privileged access mode used is the access mode of the caller.

If acmode specifies user mode, $SETSTK performs no operation and returns the SS$_NORMAL condition value.


Description

The Set Stack Limits service allows a process to change the size of its supervisor, executive, and kernel stacks by altering the values in the stack limit and base arrays held in P1 (per-process) space.

Required Access or Privileges

The calling process can adjust the size of stacks only for access modes that are equal to or less privileged than the access mode of the calling process.

Required Quota

None

Related Services

$ADJSTK, $ADJWSL, $CRETVA, $CRMPSC, $DELTVA, $DGBLSC, $EXPREG, $LCKPAG, $LKWSET, $MGBLSC, $PURGWS, $SETPRT, $SETSWM, $ULKPAG, $ULWSET, $UPDSEC, $UPDSECW


Condition Values Returned

SS$_NORMAL The service completed successfully.
SS$_ACCVIO The input address array cannot be read by the caller; the input range is invalid; or the return address array cannot be written by the caller.

$SETSTK_64 (Alpha and I64)

On Alpha and I64 systems, allows a process to change the size of its supervisor, executive, and kernel stacks by altering the values in the stack limit for a memory stack or a register stack and base arrays held in P1 (per-process) space.

Format

SYS$SETSTK_64 start_va_64 ,length_64 ,acmode, flags, prev_start_va, prev_length


C Prototype

int sys$setstk_64 (void *start_va_64, unsigned __int64 length_64, unsigned int acmode, unsigned int flags, void ** prev_start_va_64, unsigned __int64 * prev_length_64);


Arguments

start_va_64


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

Lowest address in range of addresses that express the stack's new limits. For a memory stack, this address is the stack limit. For an I64 register stack, this address is the stack base.

length_64


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

Length of the range of addresses that express the stack's new limits.

acmode


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

Access mode of the stack to be altered. The acmode argument is a longword containing the access mode. The $PSLDEF macro defines symbols for the four access modes. The most privileged access mode used is the access mode of the caller.

If acmode specifies user mode, $SETSTK_64 performs no operation and returns the SS$_NORMAL condition value.

flags


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

0 for memory stack (Alpha and I64) VA$M_SETSTK_REGISTER for register stack (I64 only)

The $VADEF macro and VADEF.H file define symbolic names for the flags argument.

prev_start_va_64


OpenVMS usage: address
type: quadword address
access: write only
mechanism: by reference

Lowest address in the range of addresses that express the stack's previous limits. For a memory stack, this address was the stack limit. For an I64 register stack, this address was the stack base.

prev_length_64


OpenVMS usage: length
type: quadword
access: write only
mechanism: by reference

Length of the range of addresses that express the stack's previous limits.

Description

The Set Stack Limits service allows a process to change the size of its supervisor, executive, and kernel stacks by altering the values in the stack limit and base arrays held in P1 (per-process) space. For Alpha, only the memory stack limits can be changed. The address range must be within 32-bit address space. For IA64, either the memory stack or register stacklimits can be changed. The address range for the register stack can be in 64-bit address space.

Required Access or Privileges

The calling process can adjust the size of stacks only for access modes that are equal to or less privileged than the access mode of the calling process.

Required Quota

None

Related Services

$ADJSTK, $ADJWSL, $CRETVA_64, $DELTVA_64, $DGBLSC, $EXPREG_64, $LCKPAG_64, $LKWSET_64, $MGBLSC_64, $PURGWS, $SETPRT_64, $ULKPAG_64, $ULWSET_64, $UPDSEC_64, $UPDSECW_64


Condition Values Returned

SS$_NORMAL The service completed successfully.
SS$_ACCVIO The prev_start_va_64 or prev_length_64 argument cannot be written by the caller.
SS$_LENVIO Memory stack limits were specified in 64-bit address space. Only 32-bit addresses are supported for the memory stack limits.


Previous Next Contents Index