uiomove

- copy kernel data using uio structure

Synopsis

#include <sys/types.h>
#include <sys/uio.h>

int uiomove(caddr_t address, size_t nbytes, enum uio_rw rwflag, 
     uio_t *uio_p);

Interface Level

Architecture independent level 1 (DDI/DKI).

Parameters

address

Source/destination kernel address of the copy.

nbytes

Number of bytes to copy.

rwflag

Flag indicating read or write operation. Possible values are UIO_READ and UIO_WRITE.

uio_p

Pointer to the uio structure for the copy.

Description

The uiomove() function copies nbytes of data to or from the space defined by the uio structure (described in uio(9S)) and the driver.

The uio_segflg member of the uio(9S) structure determines the type of space to or from which the transfer is being made. If it is set to UIO_SYSSPACE, the data transfer is between addresses in the kernel. If it is set to UIO_USERSPACE, the transfer is between a user program and kernel space.

rwflag indicates the direction of the transfer. If UIO_READ is set, the data will be transferred from address to the buffer(s) described by uio_p. If UIO_WRITE is set, the data will be transferred from the buffer(s) described by uio_p to address.

In addition to moving the data, uiomove() adds the number of bytes moved to the iov_base member of the iovec(9S) structure, decreases the iov_len member, increases the uio_offset member of the uio(9S) structure, and decreases the uio_resid member.

This function automatically handles page faults. nbytes does not have to be word-aligned.

Return Values

The uiomove() function returns 0 upon success or EFAULT on failure.

Context

User context only, if uio_segflg is set to UIO_USERSPACE. User, interrupt, or kernel context, if uio_segflg is set to UIO_SYSSPACE.

See Also

ureadc(9F), uwritec(9F), iovec(9S), uio(9S)

Writing Device Drivers

Warnings

If uio_segflg is set to UIO_SYSSPACE and address is selected from user space, the system may panic.