dkio.4

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 4 代码 · 共 166 行

.\" SCCSID: @(#)dkio.4	2.1	3/10/87
.TH dkio 4 VAX
.SH Name
dkio \- disk interface
.SH Syntax
\fB#include <sys/fs.h>\fR
.br
\fB#include <sys/ioctl.h>\fR
.SH Description
.NXA "disk interface" "dkio file"
.NXR "dkio file" "ioctl codes"
This section describes the ioctl (input/output controller) codes for all
disk drivers.
.NXR "disk interface" "ioctl codes"
The basic ioctl (input/output controller) format is:
.sp
.br
\fB#include <sys/fs.h>\fR
.br
\fB#include <sys/ioctl.h>\fR
.br
\fBioctl\fR(\fIfildes, code, arg)\fR
.br
\fBstruct pt\fR *\fR\fIarg\fR;
.sp 
The applicable \fIcodes\fR are:
.IP DIOCGETPT 16
Indicates to the driver to store
the information in the current partition table in
the address pointed to by \fIarg\fR.
The file descriptor must be opened on the raw
partitions, \fIa\fR or \fIc\fR.
.IP
DIOCGETPT does not change the partition table,
but it does provide access to the partition table information.
.IP DIOCSETPT
Indicates to the driver to modify
the current partition table with the information
pointed to by \fIarg\fR.
.IP
The file descriptor must be opened on the raw
partitions, \fIa\fR or \fIc\fR.
.IP
If the \fIa\fR or \fIc\fR partition is not mounted,
only the partition table in the driver is modified.
This temporarily modifies the partition table of the disk.
The modifications are overwritten with the default table
when the disk is turned off and on.
.IP
If the \fIa\fR or \fIc\fR partition is mounted,
both the partition table in the driver and the partition table in
the primary superblock are modified.
This permanently modifies the partition table of the disk.
This is not recommended.
To change a partition table permanently,
use the 
.MS chpt 8
command.
.IP DIOCDGTPT
Indicates to the driver to store
the \fIdefault\fR information of the current partition table in
the address pointed to by \fIarg\fR.
The file descriptor must be opened on the raw
partitions, \fIa\fR or \fIc\fR.
.IP
DIOCGETPT does not change the partition table,
but it does provide access to the partition table information.
.IP DKIOCGET
Allows the user to receive generic disk information as defined in
.PN <sys/devio.h> 
.I struct devget.
.IP DKIOCACC
This code is defined in 
.PN <sys/bbr.h>.
For an MSCP class disk, the driver performs
one of the following functions:
.RS 18
.IP ACC_REVEC 11
Forces revector of a specified disk block.
.IP ACC_SCAN
Scans an area of the disk reporting any forced errors
found and revectoring any bad blocks found.
.RE
.IP DKIOCEXCL
This command is used to set and clear the exclusive access attribute
on controllers that provide multihost support.  In this case \fIarg\fR
is an integer pointer.  If the value of \fIarg\fR is 0 the exclusive access
attribute will be cleared.  If the value of \fIarg\fR is nonzero the
exclusive access attribute will be set.  The exclusive access attribute
is set on a per-drive basis and can not be used selectively on individual
partitions.
.IP
Attempts to clear the exclusive attribute will fail if the drive is not
currently set exclusive access to the issuing host or the underlying
controller or driver does not support multihost exclusive access.
Attempts to set the exclusive attribute will fail if the drive is already
exclusively associated with another host or the underlying
controller or driver does not support multihost exclusive access.
.SH Examples
This example shows how to use the DIOGETPT ioctl code to
print the length and offset of the \fIa\fR partition of an RA81 disk:
.NXR(e) "disk interface" "DIOGETPT and"
.EX 0
#include <sys/types.h>
#include <sys/param.h>
#include <sys/fs.h>
#include <sys/ioctl.h>

main()
{
	struct pt arg;
	int fd, i;

	/* Open the "a" partition of the disk you want to see */

	if ( (fd = open("/dev/rra0a",0)) < 0 ) {
		printf("Unable to open device\\n");
		exit(2);
	}

	/* Get the partition information */

	if ( ioctl(fd,DIOCGETPT,&arg) < 0 )
		printf("Error in ioctl\\n");

	printf("Length\\t\\tOffset\\n");


	for ( i = 0; i <= 7; i++ ) {
		printf("%d\\t\\t%d\\n",arg.pt_part[i].pi_nblocks,
				  arg.pt_part[i].pi_blkoff );
	}
}
.EE
.SH Restrictions
.NXR "disk interface" "restricted"
These restrictions apply when using the DIOCSETPT ioctl code:
.IP \(bu 4
You must have superuser privileges.
.IP \(bu
You cannot shrink or change the offset of a partition
with a file system mounted on it
or with an open file descriptor on the entire partition.
.IP \(bu
You cannot change the offset of the \fIa\fR partition.
.IP \(bu
The exclusive access ioctl DKIOCEXCL is only supported on HSC version V5.00
or later.
.SH Files
.PN /dev/{r}ra???
.br
.PN /dev/{r}hp???
.br
.PN /dev/{r}rb???
.br
.PN /dev/{r}rd???
.br
.PN /dev/{r}rk???
.br
.PN /dev/{r}rl???
.br
.PN /dev/{r}rx???
.SH See Also
hp(4), ra(4), rb(4), rd(4), rk(4), rl(4), rx(4), disktab(5), fstab(5), chpt(8), 
diskpart(8), fsck(8), MAKEDEV(8), mkfs(8), tunefs(8)