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NAME
       __strncpy_from_user - Copy a NUL terminated string from userspace, with
       less checking.


SYNOPSIS
       long __strncpy_from_user  (char * dst, const char __user * src,
                                   long count);


ARGUMENTS
       dst    Destination  address,  in  kernel  space. This buffer must be at
              least count bytes long.

       src    Source address, in user space.

       count  Maximum number of bytes to copy, including the trailing NUL.


DESCRIPTION
       Copies a NUL-terminated string from userspace to kernel  space.  Caller
       must  check  the  specified  block  with  access_ok before calling this
       function.

       On success, returns  the  length  of  the  string  (not  including  the
       trailing NUL).

       If  access to userspace fails, returns -EFAULT (some data may have been
       copied).

       If count is smaller than the length of the string, copies  count  bytes
       and returns count.