COPYIN(9)

NAME
copyin, copyout, copystr, copyinstr, copyoutstr, kcopy - kernel copy functions

SYNOPSIS
#include <sys/types.h>
#include <sys/systm.h>
int
copyin(const void *uaddr, void *kaddr, size_t len);
int
copyout(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);
int
copyoutstr(const void *kaddr, void *uaddr, size_t len, size_t *done);
int
kcopy(const void *kfaddr, void *kdaddr, size_t len);

DESCRIPTION
The copyin functions are designed to copy contiguous data from one address to another. All but copystr() and kcopy() copy data from user-space to kernel-space or vice-versa.

The copyin routines provide the following functionality:

copyin()
    Copies len bytes of data from the user-space address uaddr to the kernel-space address kaddr.

copyout()
    Copies len bytes of data from the kernel-space address kaddr to the user-space address uaddr.

copystr()
    Copies a null-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 null, is returned in *done, if done is not NULL.

    Unlike the other copyin functions, copystr() does not support returning EFAULT when a bad address is encountered.

copyinstr()
    Copies a null-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 null, is returned in *done, if done is not NULL.

copyoutstr()
    Copies a null-terminated string, at most len bytes long, from kernel-space address kaddr to user-space address uaddr. The number of bytes actually copied, including the terminating null, is returned in *done, if done is not NULL.

kcopy()
    Copies len bytes of data from the kernel-space address kfaddr to the kernel-space address kdaddr.

RETURN VALUES
The copyin functions return 0 on success or EFAULT if a bad address is encountered. In addition, the copystr(), copyinstr(), and copyoutstr() functions return ENAMETOOLONG if the string is longer than len bytes.