Function
The vn_listen operation identifies
the socket as a server and establishes the maximum number of incoming
connection requests that can be queued.
Input parameter format
vn_listen (Token_structure,
OSI_structure,
Audit_structure,
Backlog,
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.
- Backlog
- Supplied parameter
- Type:
- Integer
- Length:
- Fullword
A fullword that specifies the maximum number of
connection requests that can be queued.
- Return_value
- Returned parameter
- Type:
- Integer
- Length:
- Fullword
A fullword in which the vn_listen 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_listen operation stores
the return code. The vn_listen 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_listen operation should support
at least the following error values:
Return_code |
Explanation |
---|
EINVAL |
Either a bind has not been issued on this socket; a listen
was already done; or this socket has been connected. |
EOPNOTSUPP |
Listen is valid only for stream sockets. |
- Reason_code
- Returned parameter
- Type:
- Integer
- Length:
- Fullword
A fullword in which the vn_listen operation stores
the reason code. The vn_listen 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_listen 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 listen function.
- Specific processing notes
- None.
- Serialization provided by the LFS
The vn_listen operation is invoked with an exclusive latch
held on the vnode of the socket.
- Security calls to be made by the PFS
- None.