table of contents
COPY(9) | Kernel Developer's Manual | COPY(9) |
NAME¶
copy
, copyin
,
copyin_nofault
, copyout
,
copyout_nofault
, copystr
,
copyinstr
—
SYNOPSIS¶
#include <sys/types.h>
#include <sys/systm.h>
int
copyin
(const
void *uaddr, void
*kaddr, size_t
len);
int
copyin_nofault
(const
void *uaddr, void
*kaddr, size_t
len);
int
copyout
(const
void *kaddr, void
*uaddr, size_t
len);
int
copyout_nofault
(const
void *kaddr, void
*uaddr, size_t
len);
int
copystr
(const
void *kfaddr, void
*kdaddr, size_t
len, size_t
*done);
int
copyinstr
(const
void *uaddr, void
*kaddr, size_t len,
size_t *done);
DESCRIPTION¶
Thecopy
functions are designed to copy contiguous data
from one address to another. All but copystr
() copy
data from user-space to kernel-space or vice-versa.
The copyin
() and
copyin_nofault
() functions copy
len bytes of data from the user-space address
uaddr to the kernel-space address
kaddr.
The copyout
() and
copyout_nofault
() functions copy
len bytes of data from the kernel-space address
kaddr to the user-space address
uaddr.
The copyin_nofault
() and
copyout_nofault
() functions require that the
kernel-space and user-space data be accessible without incurring a page
fault. The source and destination addresses must be physically mapped for
read and write access, respectively, and neither the source nor destination
addresses may be pageable.
The copystr
() function copies a
NUL-terminated string, at most len bytes long, from
kernel-space address kfaddr to kernel-space address
kdaddr. The number of bytes actually copied, including
the terminating NUL, is returned in *done (if
done is
non-NULL
).
The copyinstr
() function copies a
NUL-terminated string, at most len bytes long, from
user-space address uaddr to kernel-space address
kaddr. The number of bytes actually copied, including
the terminating NUL, is returned in *done (if
done is
non-NULL
).
RETURN VALUES¶
Thecopy
functions return 0 on success. All but
copystr
() return EFAULT
if a
bad address is encountered. The copyin_nofault
() and
copyout_nofault
() functions return
EFAULT
if a page fault occurs. The
copystr
() and copyinstr
()
functions return ENAMETOOLONG
if the string is longer
than len bytes.
SEE ALSO¶
fetch(9), store(9)June 15, 2017 | Linux 4.19.0-10-amd64 |