focal (9) copy.9freebsd.gz

NAME

     copy, copyin, copyin_nofault, copyout, copyout_nofault, copystr, copyinstr — kernel copy functions

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

     The copy 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

     The copy 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)