#lofiadm
在solaris8上man了一下：
bash-2.03# man lofiadm
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Maintenance Commands lofiadm(1M)
NAME
lofiadm - administer files available as block devices
through lofi
SYNOPSIS
/usr/sbin/lofiadm -a file [ device ]
/usr/sbin/lofiadm -d file | device
/usr/sbin/lofiadm [ file | device ]
DESCRIPTION
lofiadm administers lofi(7D), the loopback file driver.
lofi(7D) allows a file to be associated with a block device.
That file can then be accessed through the block device.
This is useful when the file contains an image of some
filesystem (such as a floppy or CD-ROM image), because the
block device can then be used with the normal system utili-
ties for mounting, checking or repairing filesystems. See
fsck(1M) and mount(1M).
Use lofiadm to add a file as a loopback device, remove such
an association, or print information about the current asso-
ciations.
OPTIONS
The following options are supported:
-a file [device]
Add file as a block device.
If device is not specified, an available device is
picked.
If device is specified, lofiadm attempts to assign it
to file. device must be available or lofiadm will
fail. The ability to specify a device is provided for
use in scripts that wish to re-establish a particular
set of associations.
-d file | device
Remove an association by file or device name, if the
associated block device is not busy, and de-allocates
the block device.
OPERANDS
The following operands are supported:
file Print the block device associated with file.
device
Print the file name associated with the block device
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Maintenance Commands lofiadm(1M)
device.
Without arguments, print a list of the current associ-
ations. Filenames must be valid absolute pathnames.
When a file is added, it is opened for reading or
writing by root. Any restrictions apply (such as res-
tricted root access over NFS). The file is held open
until the association is removed. It is not actually
accessed until the block device is used, so it will
never be written to if the block device is only opened
read-only.
EXAMPLES
Example 1: Mounting an existing CD-ROM image
You should ensure that Solaris understands the image before
creating the CD. lofi allows you to mount the image and see
if it works.
This example mounts an existing CD-ROM image (sparc.iso), of
the Red Hat 6.0 CD which was downloaded from the Internet.
It was created with the mkisofs utility from the Internet.
Use lofiadm to attach a block device to it:
# lofiadm -a /home/mike_s/RH6.0/sparc.iso
/dev/lofi/1
lofiadm picks the device and prints the device name to the
standard output. You can run lofiadm again by issuing the
following command:
# lofiadm
Block Device File
/dev/lofi/1 /home/mike_s/RH6.0/sparc.iso
Or, you can give it one name and ask for the other, by issu-
ing the following command:
# lofiadm /dev/lofi/1
/home/mike_s/RH6.0/sparc.iso
Use the mount command to mount the image:
# mount -F hsfs -o ro /dev/lofi/1 /mnt
Check to ensure that Solaris understands the image:
# df -k /mnt
Filesystem kbytes used avail capacity Mounted on
/dev/lofi/1 512418 512418 0 100% /mnt
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Maintenance Commands lofiadm(1M)
# ls /mnt
./ RedHat/ doc/ ls-lR rr_moved/
../ TRANS.TBL dosutils/ ls-lR.gz sbin@
.buildlog bin@ etc@ misc/ tmp/
COPYING boot/ images/ mnt/ usr@
README boot.cat* kernels/ modules/
RPM-PGP-KEY dev@ lib@ proc/
Solaris can mount the CD-ROM image, and understand the
filenames. The image was created properly, and you can now
create the CD-ROM with confidence.
As a final step, unmount and detach the images:
# umount /mnt
# lofiadm -d /dev/lofi/1
# lofiadm
Block Device File
Example 2: Mounting a floppy image
This is similar to Example 1.
Using lofi to help you mount files that contain floppy
images is helpful if a floppy disk contains a file that you
need, but the machine which you're on doesn't have a floppy
drive. It is also helpful if you don't want to take the time
to use the dd command to copy the image to a floppy.
This is an example of getting to MDB floppy for Solaris x86:
# lofiadm -a /export/s28/MDB_s28x_wos/latest/boot.3
/dev/lofi/1
# mount -F pcfs /dev/lofi/1 /mnt
# ls /mnt
./ COMMENT.BAT* RC.D/ SOLARIS.MAP*
../ IDENT* REPLACE.BAT* X/
APPEND.BAT* MAKEDIR.BAT* SOLARIS/
# umount /mnt
# lofiadm -d /export/s28/MDB_s28x_wos/latest/boot.3
Example 3: Making a UFS filesystem on a file
Making a UFS filesystm on a file can be useful, particularly
if a test suite requires a scratch filesystem. It can be
painful (or annoying) to have to re-partition a disk just
for the test suite, but you don't have to. You can newfs a
file with lofi
Create the file:
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# mkfile 35m /export/home/test
Attach it to a block device. You also get the character dev-
ice that newfs requires, so newfs that:
# lofiadm -a /export/home/test
/dev/lofi/1
# newfs /dev/rlofi/1
newfs: construct a new file system /dev/rlofi/1: (y/n)? y
/dev/rlofi/1: 71638 sectors in 119 cylinders of 1 tracks, 602 sectors
35.0MB in 8 cyl groups (16 c/g, 4.70MB/g, 2240 i/g)
super-block backups (for fsck -F ufs -o b=#) at:
32, 9664, 19296, 28928, 38560, 48192, 57824, 67456,
Note that ufs might not be able to use the entire file.
Mount and use the filesystem:
# mount /dev/lofi/1 /mnt
# df -k /mnt
Filesystem kbytes used avail capacity Mounted on
/dev/lofi/1 33455 9 30101 1% /mnt
# ls /mnt
./ ../ lost+found/
# umount /mnt
# lofiadm -d /dev/lofi/1
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environ-
ment variables that affect the execution of lofiadm:
LC_CTYPE, LC_MESSAGES and NLSPATH.
EXIT STATUS
The following exit values are returned:
0 Successful completion.
>0 An error occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| ____________________________|_____________________________|_
| Availability | SUNWcsu |
|_____________________________|_____________________________|
SEE ALSO
fsck(1M), mount(1M), mount_ufs(1M), attributes(5), lofi(7D)
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NOTES
Just as you would not directly access a disk device that has
mounted file systems, you should not access a file associ-
ated with a block device except through the lofi file
driver. It might also be appropriate to ensure that the file
has appropriate permissions to prevent such access.
Associations are not persistant across reboots. A script can
be used to re-establish them if required.
The abilities of lofiadm, and who can use them, are con-
trolled by the permissions of /dev/lofictl. Read-access
allows query operations, such as listing all the associa-
tions. Write-access is required to do any state-changing
operations, like adding an association. As shipped,
/dev/lofictl is owned by root, in group sys, and mode 0644,
so all users can do query operations but only root can
change anything. The should probably only be given to a
trusted group.
When mounting a filesystem image, take care to use appropri-
ate mount options. In particular, the nosuid mount option
might be appropriate for UFS images whose origin is unknown.
Also, some options might not be useful or appropriate, like
logging or forcedirectio for UFS. For compatability pur-
poses, a raw device is also exported along with the block
device. For example, newfs(1M) requires one.
The output of lofiadm (without arguments) may change in
future releases.
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bash-2.03#
发现有挺好的。
