HP-UX Reference (11i v3 07/02) - 7 Device (Special) Files, 9 General Information, Index (vol 10)

s
scsi_ctl(7) scsi_ctl(7)
esctl_io.data_length = MAX_LEN; /* maximum transfer length */
esctl_io.max_msecs = 10000; /* allow 10 seconds for cmd */
if (ioctl(fildes, SIOC_IO_EXT, &esctl_io) < 0) {
/* request is invalid */
} else {
if ( esctl_io.cdb_status == S_GOOD) {
/* success. display inquiry data */
else {
/* failure. process depending on cdb_status */
}
}
The following example attempts a SCSI TEST UNIT READY
command and checks to see if the device is
ready, not ready, or in some other state.
#include <sys/scsi.h>
struct sctl_io sctl_io;
memset(&sctl_io, 0, sizeof(sctl_io)); /* clear reserved fields */
sctl_io.flags = 0; /* no data transfer expected */
sctl_io.cdb[0] = 0x00; /* can use CMDtest_unit_ready */
sctl_io.cdb[1] = 0x00;
sctl_io.cdb[2] = 0x00;
sctl_io.cdb[3] = 0x00;
sctl_io.cdb[4] = 0x00;
sctl_io.cdb[5] = 0x00;
sctl_io.cdb_length = 6; /* 6 byte command */
sctl_io.data = NULL; /* no data buffer is provided */
sctl_io.data_length = 0; /* do not transfer data */
sctl_io.max_msecs = 10000; /* allow 10 seconds for cmd */
if (ioctl(leg_fildes, SIOC_IO, &sctl_io) < 0) {
/* request is invalid */
} else if (sctl_io.cdb_status == S_GOOD) {
/* device is ready */
} else if (sctl_io.cdb_status == S_BUSY ||
(sctl_io.cdb_status == S_CHECK_CONDITION &&
sctl_io.sense_status == S_GOOD &&
sctl_io.sense_xfer>2&&
(sctl_io.sense[2] & 0x0F) == 2)) {
/* can use sense_data */
/* device is not ready */
} else {
/* unknown state */
}
WARNINGS
Incorrect use of
scsi_ctl operations (even those attempting access to non-existent devices) can cause
data loss, system panics, and device damage.
The SIOC_EXCLUSIVE ioctl should be used to gain exclusive access to a device prior to attempting
SIOC_IO commands. If exclusive access is not obtained, SIOC_IO commands will be intermixed with
device-specific driver commands, which can lead to undesirable results.
Device-specific drivers can reject inappropriate or troublesome SIOC_IO_EXT /SIOC_IO commands.
However, since not all such operations are known and detected, care should be exercised to avoid disrupt-
ing device-specific drivers when using commands that modify internal device states.
Most SCSI commands have a logical unit number (LUN) field. Parallel SCSI implementations on the HP-
UX operating system select logical units via the SCSI IDENTIFY message. The LUN portion of the cdb
should normally be set to zero, even when the LUN being accessed is not zero.
Use of linked commands is not supported.
Most SCSI commands with a data phase expect the data length information to be included somewhere in
the command bytes. Both the data_length field and any cdb data length values must be correctly specified
162 Hewlett-Packard Company − 9 − HP-UX 11i Version 3: February 2007