int request, struct uscsi_cmd
uscsicommand is very powerful and somewhat dangerous; therefore it has some permission restrictions. See WARNINGS for more details.
Drivers supporting this ioctl(2) provide a
general interface allowing user-level applications to cause individual
SCSI commands to be directed to a particular
SCSI or ATAPI device under control of
that driver. The
uscsi command is supported by the
sd(7D) driver for SCSI disks and
ATAPI CD-ROM drives, and by the st(7D)
driver for SCSI tape drives.
may also be supported by other device drivers; see the specific device
driver manual page for complete information.
Applications must not assume that all Solaris disk device drivers
uscsi ioctl command. The
SCSI command may include a data transfer to or from that
device, if appropriate for that command. Upon completion of the command, the
user application can determine how many bytes were transferred and the
status returned by the device. Also, optionally, if the command returns a
Check Condition status, the driver will automatically issue a Request Sense
command and return the sense data along with the original status. See the
USCSI_RQENABLE flag below for this Request Sense
processing. The uscsi_cmd structure is defined in
includes the following members:
int uscsi_flags; /* read, write, etc. see below */ short uscsi_status; /* resulting status */ short uscsi_timeout; /* Command Timeout */ caddr_t uscsi_cdb /* CDB to send to target */ caddr_t uscsi_bufaddr; /* i/o source/destination */ size_t uscsi_buflen; /* size of i/o to take place*/ size_t uscsi_resid; /* resid from i/o operation */ uchar_t uscsi_cdblen; /* # of valid CDB bytes */ uchar_t uscsi_rqlen; /* size of uscsi_rqbuf */ uchar_t uscsi_rqstatus; /* status of request sense cmd */ uchar_t uscsi_rqresid; /* resid of request sense cmd */ caddr_t uscsi_rqbuf; /* request sense buffer */ void *uscsi_reserved_5; /* Reserved for future use */
The fields of the uscsi_cmd structure have the following meanings:
The uscsi_flags field defines the following:
USCSI_WRITE /* send data to device */ USCSI_SILENT /* no error messages */ USCSI_DIAGNOSE /* fail if any error occurs */ USCSI_ISOLATE /* isolate from normal commands */ USCSI_READ /* get data from device */ USCSI_ASYNC /* set bus to asynchronous mode */ USCSI_SYNC /* return bus to sync mode if possible */ USCSI_RESET /* reset target */ USCSI_RESET_TARGET /* reset target */ USCSI_RESET_LUN /* reset logical unit */ USCSI_RESET_ALL /* reset all targets */ USCSI_RQENABLE /* enable request sense extensions */ USCSI_RENEGOT /* renegotiate wide/sync on next I/O */
The uscsi_flags bits have the following interpretation:
USCSI_RESETis maintained only for compatibility with old applications).
USCSI_RESET_LUNare mutually exclusive options and issuing them in any simultaneous combination will result in implementation-dependent behavior When a USCSI reset request is combined with other SCSI commands, the following semantics take effect: If the
USCSI RESETflag is specified, the other fields (other than uscsi_flags) in the uscsi_cmd are ignored. The uscsi_cdblen field must be set to zero.
FLAG_RENEGOTIATE_WIDE_SYNCflag in the SCSI packet before passing the command to an adapter driver for transport. See the scsi_pkt(9S) flag
FLAG_RENEGOTIATE_WIDE_SYNCfor more information.
The uscsi_xfer_t is a type definition that
corresponds to a 64-bit unsigned integer. It should be used for the
USCSIMAXXFER ioctls. This is used for determining
the maximum transfer size that can be performed in a single
USCSICMD ioctl. If the SCSI request is larger than
the specified size, then it may not work, depending on the hardware
ioctl() supported by drivers providing the
USCSICMDioctl for the current device will be returned in the uscsi_xfer_t.
Not all devices which support the
USCSICMD ioctl also support the
ANSI Small Computer System Interface-2 (SCSI-2).
uscsicommand is very powerful, but somewhat dangerous, and so its use is restricted to processes running as root, regardless of the file permissions on the device node. The device driver code expects to own the device state, and
uscsicommands can change the state of the device and confuse the device driver. It is best to use
uscsicommands only with no side effects, and avoid commands such as Mode Select, as they may cause damage to data stored on the drive or system panics. Also, as the commands are not checked in any way by the device driver, any block may be overwritten, and the block numbers are absolute block numbers on the drive regardless of which slice number is used to send the command.
uscsi interface is not recommended for
very large data transfers (typically more than 16MB). If the requested
transfer size exceeds the maximum transfer size of the DMA engine, it will
not be broken up into multiple transfers and DMA errors may result. The
USCSIMAXXFER ioctl can be used to determine the
maximum transfer size.
USCSICMD ioctl associates a
struct uscsi_cmd with a device by using an open file
descriptor to the device. Other APIs might provide the same
struct uscsi_cmd programming interface, but perform
device association in some other manner.
|October 23, 2017||illumos|