UIOMOVE(9) | Kernel Developer's Manual | UIOMOVE(9) |
uiomove
—
#include <sys/systm.h>
int
uiomove
(void
*buf, size_t n,
struct uio *uio);
uiomove
() function copies up to
n bytes between the kernel-space address pointed to by
buf and the addresses described by
uio, which may be in user-space or kernel-space.
The uio argument is a pointer to a
struct uio as defined by
<sys/uio.h>
:
struct uio { struct iovec *uio_iov; int uio_iovcnt; off_t uio_offset; size_t uio_resid; enum uio_rw uio_rw; struct vmspace *uio_vmspace; };
A struct uio typically describes data in motion. Several of the fields described below reflect that expectation.
struct iovec { void *iov_base; size_t iov_len; };
The members in the struct iovec should only be initialized. These are:
The value of uio->uio_rw controls whether
uiomove
() copies data from buf
to uio or vice versa.
The lesser of n or uio->uio_resid bytes are copied.
uiomove
() changes fields of the structure
pointed to by uio, such that
uio->uio_resid is decremented by the amount of data
moved, uio->uio_offset is incremented by the same
amount, and the array of iovecs is adjusted to point that much farther into
the region described. This allows multiple calls to
uiomove
() to easily be used to fill or drain the
region of data.
uiomove
() returns 0. If a
bad address is encountered, EFAULT
is returned.
April 26, 2010 | NetBSD 9.0 |