copyreq(D4) copyreq(D4)
NAME
copyreq - STREAMS transparent ioctl copy request structure
SYNOPSIS
#include <sys/stream.h>
#include <sys/ddi.h>
DESCRIPTION
The copyreq structure contains the information necessary to
process transparent ioctls.
USAGE
The copyreq structure is used in M_COPYIN and M_COPYOUT
messages. The module or driver usually converts an M_IOCTL or
M_IOCDATA message into an M_COPYIN or M_COPYOUT message. The
copyreq structure is thus overlaid on top of the iocblk(D4) or
copyresp(D4) structure. The stream head guarantees that the
message is large enough to contain the different structures.
Structure Definitions
The copyreq structure contains the following members:
int cq_cmd; /* ioctl command */
cred_t *cq_cr; /* user credentials */
uint_t cq_id; /* ioctl ID */
caddr_t cq_addr; /* copy buffer address */
uint_t cq_size; /* number of bytes to copy */
int cq_flag; /* for future use */
mblk_t *cq_private; /* module private data */
The cq_cmd field is the ioctl command, copied from the ioc_cmd
field of the iocblk structure. If the same message is used,
then the cq_cmd field directly overlays the ioc_cmd field
(that is, it need not be copied.)
The cq_cr field contains a pointer to the user credentials.
It is copied from the ioc_cr field of the iocblk structure.
If the same message is used, then the cq_cr field directly
overlays the ioc_cr field (that is, it need not be copied.)
The cq_id field is the ioctl ID, copied from the ioc_id field
of the iocblk structure. It is used to uniquely identify the
ioctl request in the stream. If the same message is used,
then the cq_id field directly overlays the ioc_id field (that
is, it need not be copied.)
Copyright 1994 Novell, Inc. Page 1
copyreq(D4) copyreq(D4)
For an M_COPYIN message, the cq_addr field contains the user
address from which the data are to be copied. For an
M_COPYOUT message, the cq_addr field contains the user address
to which the data are to be copied. In both cases, the
cq_size field contains the number of bytes to copy.
The cq_flag field is reserved for future use and should be set
to 0 by the module or driver.
The cq_private field is a field set aside for use by the
driver. It can be used to hold whatever state information is
necessary to process the ioctl. It is copied to the
cp_private field in the resultant M_IOCDATA message. When the
M_COPYIN or M_COPYOUT message is freed, any message that
cq_private refers to is not freed by the STREAMS subsystem.
It is the responsibility of the module or driver to free it.
REFERENCES
copyresp(D4), datab(D4), iocblk(D4), messages(D5), msgb(D4)
NOTICES
Portability
All processors
Copyright 1994 Novell, Inc. Page 2