vn_sockopt — Get or set socket options

Function

The vn_sockopt operation gets or sets options that are associated with a socket.

Environment on entry and exit

Input parameter format

vn_sockopt  (Token_structure,
             OSI_structure,
             Audit_structure,
             Direction,
             Level,
             Option,
             Option_data_length,
             Option_data,
             Return_value,
             Return_code,
             Reason_code)

Parameters

Token_structure

Supplied parameter

Type:: TOKSTR
Length:: Specified by TOKSTR.ts_hdr.cblen.

The Token_structure represents the file (vnode) that is being operated on. It contains the PFS's initialization token, mount token, and the file token. Refer to LFS/PFS control block structure for a discussion of this structure, and to the TOKSTR typedef in BPXYPFSI in Interface structures for C language servers and clients for its mapping.

OSI_structure

Supplied and returned parameter

Type:: OSI
Length:: Specified by OSI.osi_hdr.cblen.

The OSI_structure contains information that is used by the OSI operations that may be called by the PFS. See OSI services for more information.

It also contains MVS-specific information that needs to be passed to the PFS, including SMF accounting fields, a work area, a recovery area, and an optional pointer to an output ATTR structure. For more details on the OSI structure, see The OSI structure.

This area is mapped by the OSI typedef in BPXYPFSI in Interface structures for C language servers and clients.

Audit_structure

Supplied parameter

Type:: CRED
Length:: Specified by CRED.cred_hdr.cblen.

The Audit_structure contains information that is used by the security product for access checks and auditing. It is passed to most SAF routines that are invoked by the PFS.

Refer to Security responsibilities and considerations for a discussion of security processing, and to the CRED typedef in BPXYPFSI in Interface structures for C language servers and clients for the mapping of this structure.

Direction

Supplied parameter

Type:: Integer
Length:: Fullword

The Direction parameter specifies whether the socket options are to be set or returned to the requester. The values for this parameter are defined in the BPXYPFSI header file (see Interface structures for C language servers and clients) and are as follows:

Value: Meaning
GET_SOCKOPT: Get the current socket options
SET_SOCKOPT: Change the socket options
SET_IBMSOCKOPT: Change SetIBMsockopt options

Level

Supplied parameter

Type:: Integer
Length:: Fullword

A fullword that specifies the protocol level. This area is mapped by socket.h.

Option

Supplied parameter

Type:: Integer
Length:: Fullword

A fullword that specifies the option that is to be set or retrieved. This area is mapped by socket.h.

Option_data_length

Supplied parameter

Type:: Integer
Length:: Fullword

The Option_data_length is a fullword that describes the length of the Option_data parameter.

Option_data

Supplied parameter

Type:: Defined by the Option
Length:: Specified by Option_data_length

For most options, this is either a zero or nonzero, depending on whether the option is disabled or enabled.

Return_value

Returned parameter

Type:: Integer
Length:: Fullword

A fullword in which the vn_sockopt operation returns the results of the operation, as one of the following:

Return_value: Meaning
-1: The operation was not successful. The Return_code and Reason_Code values must be filled in by the PFS when Return_value is -1.
0: The operation was successful.

Return_code

Returned parameter

Type:: Integer
Length:: Fullword

A fullword in which the vn_sockopt operation stores the return code. The vn_sockopt operation returns Return_code only if Return_value is -1. For a complete list of supported return code values, see z/OS UNIX System Services Messages and Codes.

The vn_sockopt operation should support at least the following error value:

Return_code	Explanation
ENOPROTOOPT	The level that was specified is an incorrect protocol.

Reason_code

Returned parameter

Type:: Integer
Length:: Fullword

A fullword in which the vn_sockopt operation stores the reason code. The vn_sockopt operation returns Reason_code only if Return_value is -1. Reason_code further qualifies the Return_code value. These reason codes are documented by the PFS.

Implementation notes

Overview of vn_sockopt processing: For more information about the semantics of this operation for a POSIX-conforming PFS, refer to the publications that are mentioned in Finding more information about sockets for the getsockopt and setsockopt functions.
Serialization provided by the LFS: The vn_sockopt operation is invoked with an exclusive latch held on the vnode of the socket.
Security calls to be made by the PFS: None.