osi_uiomove — Move data between PFS buffers and buffers defined by a UIO structure

Function

The osi_uiomove service moves blocks of data between PFS buffers and buffers that are defined by a UIO structure.

Requirements

Operation	Environment
Authorization:	Supervisor state, PSW key 0
Dispatchable unit mode:	Task or SRB
Cross memory mode:	Any
AMODE:	31-bit
ASC mode:	Any
Interrupt status:	Enabled for interrupts
Locks:	Unlocked
Control parameters:	All parameters must be addressable by the caller and in the primary address space.

Format

     osi_uiomove(OSI_structure,
              Workarea,
              PFS_Buffer,
              PFS_Buffer_Alet,
              Number_of_bytes,
              User_IO_structure,
              Return_value,
              Return_code,
              Reason_code);

Parameters

OSI_structure

Supplied parameter

Type:: Structure
Length:: Specified by the Osilen field

OSI_structure contains information that is used by the OSI operations. The PFS receives this structure on each PFS interface operation.

Refer to Interface structures for C language servers and clients for a full description of this structure.

Workarea

Supplied parameter

Type:: Char
Length:: 2048 bytes

Workarea is a buffer of 2048 bytes, aligned on a word boundary, that is to be used by this OSI operation.

PFS_Buffer

Supplied parameter

Type:: Char
Length:: N/A

The name of the buffer to or from which data is to be moved.

PFS_Buffer_Alet

Supplied parameter

Type:: Integer
Length:: Fullword

The Alet for the specified PFS_Buffer.

Number_of_bytes

Supplied parameter

Type:: Integer
Length:: Fullword

The number of bytes to move.

User_IO_structure

Supplied and returned parameter

Type:: UIO
Length:: Specified by UIO.u_hdr.cblen.

An area that contains the parameters for the I/O that is to be performed. This area is mapped by the UIO typedef in the BPXYVFSI header file (see Interface structures for C language servers and clients). See Specific processing notes for details on how the fields in this structure are processed.

Return_value

Returned parameter

Type:: Integer
Length:: Fullword

A fullword in which the osi_uiomove service returns the results of the service, as one of the following:

Return_value: Meaning
-1: The operation was not successful. The Return_code and Reason_code parameters contain the values that are returned by the service.
0 or greater: The operation was successful. The value represents the number of bytes that were transferred.

Return_code

Returned parameter

Type:: Integer
Length:: Fullword

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

Reason_code

Returned parameter

Type:: Integer
Length:: Fullword

A fullword in which the osi_uiomove service stores the reason code. The osi_uiomove service returns Return_code only if Return_value is -1. Reason_code further qualifies the Return_code value. The reason codes are described in z/OS UNIX System Services Messages and Codes.

Usage notes

The osi_uiomove service moves the number of bytes of data that is specified by the Number_of_bytes parameter or the UIO.u_count field, whichever is less. If either of these parameters is zero, no data is moved, and Return_value field is set to 0.
The u_iovresidualcnt and u_totalbytesrw fields, described in this topic, are not set until after the first call to osi_uiomove.
This service requires the calling program to run in key 0 storage, because it must update the UIO, and this structure is usually in key 0 storage. Osi_copyin and osi_copyout do not require the calling program to be in key 0 storage.
The address of the osi_uiomove routine is passed to the PFS in the OSIT structure when the PFS is initialized.
The OSI_structure contains an area, pointed to by osi_workarea, that may be passed to this service as the Workarea parameter.
The osi_indirect64 bit in BPXYPFSI indicates that the PFS_Buffer parameter is a 64-bit address that points to the PFS_ Buffer to be used by the osi_uiomove service. osi_uiomove turns this bit off before returning to the caller. Because of this, the caller of osi_uiomove is responsible for setting the osi_indirect64 flag prior to each invocation of osi_uiomove that requires a 64-bit address for the PFS_Buffer parameter.
If the osi_indirect64 flag is set, the PFS_Buffer parameter is assumed to be an 8-byte address of the actual PFS Buffer. This allows a program to call the osi_uiomove service in AMODE(31) and still pass the address of a PFS buffer that is above the bar. The osi_uiomove service turns this flag off, so it must be reset to ON for every call for which you want to use indirect buffer addressing. PFS_Buffer_Alet still refers to the actual buffer itself, not to the 8-byte pointer. The 8byte pointer must be in the primary address space.

Specific processing notes

The following UIO fields are provided by the LFS:

UIO.u_count: Specifies the number of bytes in the buffer, or the number of elements in the IOV array.
UIO.u_rw: Specifies whether the request is a read (0) or a write (1). On a read, the contents of PFS_buffer are moved to Uiouserbuffer. On a write, the contents of Uiouserbuffer are moved to PFS_buffer.
UIO.u_iovinuio: Specifies whether the user_IO_structure points to an iov structure.
UIO.u_realpage: Specifies whether the user_IO_structure contains addresses of real pages. This flag must be OFF (0), or the osi_uiomove service fails the request.
UIO.u_key: Specifies the storage key of the caller's buffer.
UIO.u_iovresidualcnt: Specifies the number of bytes remaining in the buffer or iov structure that is pointed to by the user_IO_structure.
u_totalbytesrw: Specifies the total number of bytes that are to be moved.

Related services

Characteristics and restrictions

This routine must be used only on the dispatchable unit (task or SRB) that made the vnode or VFS call because the service requires the use of the cross-memory environment of the calling dispatchable unit.
The osi_uiomove service does not support DATOFF moves; that is, it fails requests if the UIO.u_realpage flag is ON.