Using dsopen() and dsclose()

struct dsreq* dsopen(char *opath, int oflags);

opath	The name of the device special file as a character string, for example "/dev/scsi/jag0d7l0" (see "Form of Names in /dev/scsi").
oflags	The oflag value expected by open() when opening this device special file. O_EXCL has special meaning; see "Relationship to Other Device Special Files".

If the open() call fails or memory cannot be allocated, the function returns NULL. Otherwise it allocates a dsreq structure as well as generous buffers for command and sense strings. The following fields of the dsreq are initialized:

ds_time	Set to 10000 (10 second timeout).
ds_private	Set to the address of the context that contains the dsreq as well as the command and sense buffers.
ds_cmdbuf	Set to the address of the command buffer.
ds_cmdlen	Set to the length of the allocated command buffer.
ds_sensebuf	Set to the address of the allocated sense buffer.
ds_senselen	Set to the length of the sense buffer.

Other fields of the dsreq are cleared to zero.

Note: Other functions in dslib assume that a dsreq has been initialized by dsopen(). In particular they assume the ds_private value points to a context block. You should not attempt to use any dsreq structure with a dslib function except one returned by dsopen(); and you should not use a dsreq opened for one file with another file. The dsclose() function releases the dsreq structure and close the device. Its prototype is

void dsclose(struct dsreq *dsp);