NAME

copyin − copy data from a user program to a driver buffer

SYNOPSIS

#include <sys/types.h>
#include <sys/ddi.h>
int copyin(caddr_t userbuf, caddr_t driverbuf, size_t cn
);

ARGUMENTS

userbuf User program source address from which data is transferred. 

driverbuf Driver destination address to which data is transferred. 

cn Number of bytes transferred. 

INTERFACE LEVEL

Architecture independent level 1 (DDI/DKI). 

DESCRIPTION

copyin() copies data from a user program source address to a driver buffer.  The driver developer must ensure that adequate space is allocated for the destination address.

Addresses that are word-aligned are moved most efficiently.  However, the driver developer is not obligated to ensure alignment.  This function automatically finds the most efficient move according to address alignment. 

RETURN VALUES

Under normal conditions a 0 is returned indicating a successful copy.  A -1 is returned if one of the following occurs:

• paging fault; the driver tried to access a page of memory for which it did not have read or write access

• invalid user area or stack area

• invalid address that would have resulted in data being copied into the user block

If a -1 is returned to the caller, driver entry point routines should return EFAULT. 

CONTEXT

copyin() can be called from user context only.

SEE ALSO

bcopy(9F), copyout(9F), ddi_copyin(9F), ddi_copyout(9F), uiomove(9F). 

SunOS 5.1 Writing Device Drivers

NOTES

Driver writers who intend to support layered ioctls in their ioctl(9E) routines should use ddi_copyin(9F) instead. 

SunOS 5.2  —  Last change: 29 Sep 1992