NAME

useracc − verify whether user has access to memory

SYNOPSIS

#include <sys/types.h>
#include <sys/buf.h>
#include <sys/vm.h>
int useracc(caddr_t base, uint count, int access
);

ARGUMENTS

base The start address of the user data area. 

count The size of the data transfer in bytes. 

access A flag to determine whether the access is a read or write.  The defined constant B_READ specifies a read from the device and a write to memory.  This requires that the user have write access permission for the specified data area.  The defined constant B_WRITE specifies a read from memory and a write to the device.  It requires read access permission for the data area ( B_READ and B_WRITE are defined in the system header sys/buf.h). 

INTERFACE LEVEL

Architecture independent level 1 (DDI/DKI). 

DESCRIPTION

useracc() verifies if a user has proper access to memory.  It is not necessary to use useracc() for buffered I/O (including use of the copyin(9F) and copyout(9F) functions). 

RETURN VALUES

Under normal conditions, 1 is returned.  If the user does not have the proper access permission to the memory specified return EFAULT. 

CONTEXT

useracc() can be called from user or interrupt context. 

SEE ALSO

copyin(9F), copyout(9F), drv_priv(9F)

Sun Microsystems  —  Last change: 11 Apr 1991