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Note that two processes on different nodes cannot use the termination mailbox for general interprocess communication.
The accounting message is sent before process rundown is initiated but after the process name has been set to null. Thus, a significant interval of time can occur between the sending of the accounting message and the final deletion of the process.
To receive the accounting message, the caller must issue a read to the mailbox. When the I/O completes, the second longword of the I/O status block, if one is specified, contains the process identification of the deleted process.
The $ACCDEF macro defines symbolic names for offsets of fields within the accounting message. The offsets, their symbolic names, and the contents of each field are shown in the following table. Unless stated otherwise, the length of the field is 4 bytes.
| Offset | Symbolic Name | Contents |
|---|---|---|
| 0 | ACC$W_MSGTYP | MSG$_DELPROC (2 bytes) |
| 2 | Not used (2 bytes) | |
| 4 | ACC$L_FINALSTS | Exit status code |
| 8 | ACC$L_PID | External process identification |
| 12 | Not used (4 bytes) | |
| 16 | ACC$Q_TERMTIME | Current time in system format at process termination (8 bytes) |
| 24 | ACC$T_ACCOUNT | Account name for process, blank filled (8 bytes) |
| 32 | ACC$T_USERNAME | User name, blank filled (12 bytes) |
| 44 | ACC$L_CPUTIM | CPU time used by the process, in 10-millisecond units |
| 48 | ACC$L_PAGEFLTS | Number of page faults incurred by the process |
| 52 | ACC$L_PGFLPEAK | Peak paging file usage |
| 56 | ACC$L_WSPEAK | Peak working set size |
| 60 | ACC$L_BIOCNT | Count of buffered I/O operations performed by the process |
| 64 | ACC$L_DIOCNT | Count of direct I/O operations performed by the process |
| 68 | ACC$L_VOLUMES | Count of volumes mounted by the process |
| 72 | ACC$Q_LOGIN | Time, in system format, that process logged in (8 bytes) |
| 80 | ACC$L_OWNER | Process identification of owner |
The length of the termination message is equated to the constant ACC$K_TERMLEN.
| OpenVMS usage: | mask_longword |
| type: | longword (unsigned) |
| access: | read only |
| mechanism: | by value |
Each option (bit) has a symbolic name, which the $PRCDEF macro defines. You construct the stsflg argument by performing a logical OR operation using the symbolic names of each desired option. The following table describes the symbolic name of each option:
| Symbolic Name | Description |
|---|---|
| PRC$M_BATCH | Create a batch process. IMPERSONATE privilege is required. |
| PRC$M_IMPERSONATE | Create a detached process under another UIC. |
| PRC$M_DISAWS | Disable system-initiated working set adjustment. |
| PRC$M_HIBER | Force process to hibernate before it executes the image. |
| PRC$M_HOME_RAD |
Assign process to specified home resource affinity domain (RAD).
RAD is supported on AlphaServer GS series systems and starting from OpenVMS Version 8.4, support is extended to NUMA capable Integrity servers. |
| PRC$M_IMGDMP | Enable image dump facility. If an image terminates due to an unhandled condition, the image dump facility writes the contents of the address space to a file in your current default directory. The file name is the same as the name of the terminated image. The file type is .DMP. |
| PRC$M_INTER | Create an interactive process. This option is meaningful only if the image argument specifies SYS$SYSTEM:LOGINOUT.EXE. The purpose of this option is to provide you with information about the process. When you specify this option, it identifies the process as one that is in communication with another user (an interactive process). For example, if you use the DCL lexical function F$MODE to make an inquiry about a process that has specified the PRC$M_INTER option, F$MODE returns the value INTERACTIVE. |
| PRC$M_KT_LIMIT | Assign the specified kernel thread limit to the created process. |
| PRC$M_NETWRK | Create a process that is a network connect object. IMPERSONATE privilege required. |
| PRC$M_NOACNT | Do not perform accounting. ACNT privilege is required. |
| PRC$M_NOPASSWORD | Do not display the Username: and Password: prompts if the process is interactive and detached and the image is SYS$SYSTEM:LOGINOUT.EXE. If you specify this option in your call to $CREPRC, the process created by the call is logged in under the user name associated with the creating process. If you do not specify this option for an interactive process, SYS$SYSTEM:LOGINOUT.EXE prompts you for the user name and password to be associated with the process. The prompts are displayed at the SYS$INPUT device. |
| PRC$M_NOUAF |
Do not check authorization file if the process is detached and the
image is SYS$SYSTEM:LOGINOUT.EXE. You should not specify this option if
a subprocess is being created.
In previous versions of the operating system, the symbolic name of this option was PRC$M_LOGIN. The symbolic name has been changed to more accurately denote the effect of setting this bit. For compatibility with existing user programs, you can still specify this bit as PRC$M_LOGIN. This flag prevents the loading of the new process's security profile from the contents of the UAF record associated with the specified user name. Restrictions are still enforced on the UAF record, if it exists, for account disuser, account expiration, and primary/secondary days/hours. |
| PRC$M_PARSE_EXTENDED | Sets the PARSE_STYLE_PERM and the PARSE_STYLE_IMAGE properties for the new process to EXTENDED. |
| PRC$M_PSWAPM | Inhibit process swapping. PSWAPM privilege is required. |
| PRC$M_SSFEXCU | Enable system service failure exception mode. |
| PRC$M_SSRWAIT | Disable resource wait mode. |
| PRC$M_SUBSYSTEM | Inherit any protected subsystem identifiers. The default is that the new process does not inherit subsystem identifiers. |
| PRC$M_TCB | Mark a process as part of the trusted computing base (TCB). As such, it is expected to perform its own auditing. IMPERSONATE privilege is required. |
Note that options PRC$M_BATCH, PRC$M_INTER, PRC$M_NOUAF, PRC$M_NETWRK, and PRC$M_NOPASSWORD are intended for use by HP software.
| OpenVMS usage: | reserved |
| type: | longword (unsigned) |
| access: |
| OpenVMS usage: | SCS_nodename |
| type: | character-coded text string |
| access: | read only |
| mechanism: | by descriptor--fixed-length string descriptor |
| OpenVMS usage: | longword_unsigned |
| type: | longword (unsigned) |
| access: | read only |
| mechanism: | by value |
The home RAD is determined by the operating system, unless you explicitly request one. If bit PRC$M_HOME_RAD in the stsflg is set, home_rad is the RAD on which the process is to start. Note that you may set this bit to 0 on non-RAD systems.
RAD is supported on AlphaServer GS series systems and starting from OpenVMS Version 8.4, support is extended to NUMA capable Integrity servers. For more information about using RADs, see the HP OpenVMS Alpha Partitioning and Galaxy Guide.
| OpenVMS usage: | longword_signed |
| type: | longword (signed) |
| access: | read only |
| mechanism: | by value |
The number of kernel threads that can be created in a process, is by default controlled by the MULTITHREAD SYSGEN parameter. The kt_limit argument is used to further limit the number of possible kernel threads for the process.
The Create Process service creates a subprocess or detached process on behalf of the calling process. A subprocess can be created only on the current OpenVMS Cluster node. A detached process can be created on the current OpenVMS Cluster node or on the node specified with the node argument.A detached process is a fully independent process. For example, the process that the system creates when you log in is a detached process. A subprocess, on the other hand, is related to its creating process in a treelike structure; it receives a portion of the creating process's resource quotas and must terminate before the creating process. Any subprocesses that still exist when their creator is being deleted are automatically deleted.
The presence of the uic argument, node argument, or the PRC$M_IMPERSONATE flag specifies that the created process is detached.
Creating a process is synchronous in that the process has actually been created and its PID determined before control returns to the program that requested the system service. Note, however, that the new process has not necessarily begun to execute at that point. Some error conditions are not detected until the created process executes. These conditions include an invalid or nonexistent image; invalid SYS$INPUT, SYS$OUTPUT, or SYS$ERROR logical name equivalence; inadequate quotas; or insufficient privilege to execute the requested image.
In creating a detached or subprocess, you can specify that the process run the image SYS$SYSTEM:LOGINOUT.EXE. During interactive logins, LOGINOUT performs the following functions:
- It validates user name and password.
- It reads the system authorization file record associated with that user and redefines the process environment based on information from the record.
- It maps a command language interpreter (CLI) into the process and passes control to it.
The CLI reads a command from SYS$INPUT, processes it, and reads another command. The presence of the CLI enables the process to execute multiple images. It also enables an image running in the process to use Run-Time Library procedures, such as LIB$SPAWN, LIB$DO_COMMAND, and LIB$SET_LOGICAL, that require a CLI.
Running in the context of a process you create through $CREPRC, LOGINOUT can perform some or all of the preceding steps, depending on whether the process is a subprocess or a detached process and on the values of PRC$M_NOPASSWORD and PRC$M_NOUAF in the stsflg argument.
Certain characteristics of a created process can be specified explicitly through $CREPRC system service arguments, while other characteristics are propagated implicitly from the $CREPRC caller. Implicit characteristics include the following:
- Current default directory
- Creator's equivalence name for SYS$DISK
- User and account names
- Command language interpreter (CLI) name and command table file name
Note, however, that after the process has been created, if it runs LOGINOUT and LOGINOUT redefines the process environment, those characteristics will be overridden by information from the system authorization file.
Several process characteristics are relevant to the creation of a process on another OpenVMS Cluster node, in particular, process quotas, default directory, SYS$DISK equivalence name, CLI name, and CLI command table name.
Quotas for a process created on another OpenVMS Cluster node are calculated as previously described in the section on the use of the quota list; namely, they are based on explicit values passed by the creator and system parameters on the other OpenVMS Cluster node. If the other node has its own authorization file with node-specific quotas, you might want to specify in the $CREPRC request that the process run LOGINOUT so it can redefine the process environment based on that node's quotas for the user.
Unless overridden by LOGINOUT, the new process will use its creator's default disk and directory. If the disk is not mounted clusterwide, the created process might need to redefine SYS$DISK with an equivalence name that specifies a disk accessible from that node.
When you set the PRC$M_NOUAF flag in the stsflg argument and create a process running LOGINOUT, LOGINOUT will attempt to map a CLI and command table with the same file names as those running in your process. The CLI and command table images must therefore have already been installed by the system manager on the other node. Problems can arise when you are using something other than the DCL CLI and its standard command tables. For example, if you are running on a VAX node with MCR as your current CLI, LOGINOUT will be unable to map that CLI on an Alpha or Integrity servers node. The new process will be created but then aborted by LOGINOUT.
A detached process is considered an interactive process only if (1) the process is created with the PRC$M_INTER option specified and (2) SYS$INPUT is not defined as a file-oriented device.
The $CREPRC service requires system dynamic memory.
The calling process must have the following:
- IMPERSONATE or CMKRNL privilege to create any of the following types of process:
- A detached process with a UIC that is different from the UIC of the calling process
- A detached process with a larger value specified for some quota than is authorized for the caller
- A detached process on another node if the system parameter CWCREPRC_ENABLE has a value of 0
- IMPERSONATE privilege to create any of the following types of process:
- A batch process
- A network process
- A trusted computing base process
- ALTPRI privilege to create a subprocess with a higher base priority than the calling process
- SETPRV privilege to create a process with privileges that the calling process does not have
- PSWAPM privilege to create a process with process swap mode disabled
- ACNT privilege to create a process with accounting functions disabled
- OPER privilege to create a detached process on another OpenVMS Cluster node on which interactive logins have not yet been enabled
The number of subprocesses that a process can create is controlled by the subprocess (PRCLM) quota; this quota is returned when a subprocess is deleted.
The number of detached processes on any one OpenVMS Cluster node that a process can create with the same user name is controlled by the MAXDETACH entry in the user authorization file (UAF).
When a subprocess is created, the value of any deductible quota is subtracted from the total value the creating process has available, and when the subprocess is deleted, the unused portion of any deductible quota is added back to the total available to the creating process. Any pooled quota value is shared by the creating process and all its subprocesses.
$CANEXH, $DCLEXH, $DELPRC, $EXIT, $FORCEX, $GETJPI, $GETJPIW, $HIBER, $PROCESS_SCAN, $RESUME, $SETPRI, $SETPRN, $SETPRV, $SETRWM, $SUSPND, $WAKE
SS$_ACCVIO The caller cannot read a specified input string or string descriptor, the privilege list, or the quota list; or the caller cannot write the process identification. SS$_BADRAD The specified RAD contains no memory or contains no active CPUs, or the specified RAD is greater than or equal to the maximum number of RADs on the system. Use the $GETSYI item code RAD_MAX_RADS to determine the maximum number of RADs on the system. SS$_DUPLNAM The specified process name duplicates one already specified within that group. SS$_EXPRCLM The creation of a detached process failed because the creating process already reached its limit for the creation of detached processes. This limit is established by the MAXDETACH quota in the user authorization file (UAF) of the creating process. SS$_EXQUOTA At least one of the following conditions is true:
- The process has exceeded its quota for the creation of subprocesses.
- A quota value specified for the creation of a subprocess exceeds the creating process's corresponding quota.
- The quota is deductible and the remaining quota for the creating process would be less than the minimum.
SS$_INCOMPAT The remote node is running an incompatible version of the operating system, namely, one that does not support remote process creation. SS$_INSFMEM The system dynamic memory is insufficient for the requested operation. SS$_INVARG An invalid argument is specified. SS$_INVKTLIM A value lower than 0, or a value higher than the SYSGEN parameter MULTITHREAD is specified. SS$_IVLOGNAM At least one of the following two conditions is true:
- The specified process name has a length of 0 or has more than 15 characters.
- The specified image name, input name, output name, or error name has more than 255 characters.
SS$_IVQUOTAL The quota list is not in the proper format. SS$_IVSTSFLG A reserved status flag was specified. SS$_NODELEAVE The specified node was removed from the OpenVMS Cluster during the $CREPRC service's execution. SS$_NOPRIV The caller violated one of the privilege restrictions. SS$_NORMAL The service completed successfully. SS$_NOSLOT No process control block is available; in other words, the maximum number of processes that can exist concurrently in the system has been reached. SS$_NOSUCHNODE The specified node is not currently a member of the cluster. SS$_REMRSRC The remote node has insufficient resources to respond to the request. (Bring this error to the attention of your system manager.) SS$_UNREACHABLE The remote node is a member of the cluster but is not accepting requests. This is normal for a brief period early in the system boot process.
Adds a range of demand-zero allocation pagelets to a process's virtual address space for the execution of the current image.
SYS$CRETVA inadr ,[retadr] ,[acmode]
int sys$cretva (struct _va_range *inadr, struct _va_range *retadr, unsigned int acmode);
inadr
OpenVMS usage: address_range type: longword (unsigned) access: read only mechanism: by reference
Address of a 2-longword array containing the starting and ending virtual addresses of the pages to be created. If the starting and ending virtual addresses are the same, a single page is created. The addresses are adjusted up or down to fall on CPU-specific page boundaries. Only the virtual page number portion of the virtual address is used; the low order byte-within-page bits are ignored.retadr
OpenVMS usage: address_range type: longword (unsigned) access: write only mechanism: by reference--array reference or descriptor
Address of a 2-longword array to receive the starting and ending virtual addresses of the pages created.On Alpha and Integrity server systems, the retadr argument should be checked by programs for actual allocation. Because the Alpha and Integrity servers architectures define more than one page size, more space might be created than was specified in the inadr argument.
acmode
OpenVMS usage: access_mode type: longword (unsigned) access: read only mechanism: by value
Access mode and protection for the new pages. The acmode argument is a longword containing the access mode.The $PSLDEF macro defines the following symbols for the four access modes:
Symbol Access Mode PSL$C_KERNEL Kernel PSL$C_EXEC Executive PSL$C_SUPER Supervisor PSL$C_USER User The most privileged access mode used is the access mode of the caller. The protection of the pages is read/write for the resultant access mode and those more privileged.
The Create Virtual Address Space service adds a range of demand-zero allocation pages to a process's virtual address space for the execution of the current image.Pages are created starting at the address contained in the first longword of the location addressed by the inadr argument and ending with the second longword. The ending address can be lower than the starting address. The retadr argument indicates the byte addresses of the pages created.
If an error occurs while pages are being created, the retadr argument, if specified, indicates the pages that were successfully created before the error occurred. If no pages were created, both longwords of the retadr argument contain the value --1.
If $CRETVA creates pages that already exist, the service deletes those pages if they are not owned by a more privileged access mode than that of the caller. Any such deleted pages are reinitialized as demand-zero pages. For this reason, it is important to use the retadr argument to capture the address range actually created. Because the Alpha and Integrity servers architectures have a larger page size than the VAX architecture, more space is potentially affected on Alpha and Integrity server systems.
None
The paging file quota (PGFLQUOTA) of the process must be sufficient to accommodate the increased size of the virtual address space.
$ADJSTK, $ADJWSL, $CRMPSC, $DELTVA, $DGBLSC, $EXPREG, $LCKPAG, $LKWSET, $MGBLSC, $PURGWS, $SETPRT, $SETSTK, $SETSWM, $ULKPAG, $ULWSET, $UPDSEC, $UPDSECW
The Expand Program/Control Region ($EXPREG) service also adds pages to a process's virtual address space.
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