vn_getattr — Get the attributes of a file

Function

The vn_getattr operation gets the attributes of a file.

Environment on entry and exit

Input parameter format

vn_getattr  (Token_structure,
             OSI_structure,
             Audit_structure,
             Attribute_structure,
             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.

Attribute_structure

Supplied and returned parameter

Type:: ATTR
Length:: Specified by ATTR.at_hdr.cblen.

An area used by the vn_getattr operation to return the file attributes for the file that is specified by the vnode token. Before a call to vn_getattr, Attribute_structure must be initialized with the ID and length fields set correctly and the unused fields set to zero. This area is mapped by typedef ATTR in the BPXYVFSI header file (see Interface structures for C language servers and clients).

Return_value

Returned parameter

Type:: Integer
Length:: Fullword

The name of a fullword in which the vn_getattr service 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_getattr service stores the return code. The vn_getattr service returns Return_code only if Return_value is -1. See z/OS UNIX System Services Messages and Codes for a complete list of supported return code values.

Reason_code

Returned parameter

Type:: Integer
Length:: Fullword

A fullword in which the vn_getattr service stores the reason code. The vn_getattr service 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_getattr processing

vn_getattr is used to read file attributes, as described in Getting and setting attributes.

Specific processing notes

The input attribute_structure length may not match the length that is supported by the PFS. The PFS must return the minimum of:
- Input ATTR.at_hdr.cblen
- The attribute_structure length that is supported by this release of the PFS
The returned value in ATTR.at_hdr.cblen must match the size returned.
Time-related fields that are marked for update must be updated before the attributes are returned.

Serialization provided by the LFS

The vn_getattr operation is invoked with a shared latch held on the vnode of the directory.

Security calls to be made by the PFS

None.

Related services

vn_setattr — Set the attributes of a file