System Administration Commands lofiadm(1M)
NAME
lofiadm - administer files available as block devices
through lofiSYNOPSIS
/usr/sbin/lofiadm -a file [device]
/usr/sbin/lofiadm -c crypto_algorithm -a file [device]
/usr/sbin/lofiadm -c crypto_algorithm -k raw_key_file -a file [device]
/usr/sbin/lofiadm -c crypto_algorithm -T token_key -a file [device]
/usr/sbin/lofiadm -c crypto_algorithm -T token_key
-k wrapped_key_file -a file [device]
/usr/sbin/lofiadm -c crypto_algorithm -e -a file [device]
/usr/sbin/lofiadm -C algorithm [-s segment_size] file
/usr/sbin/lofiadm -d file | device
/usr/sbin/lofiadm -U file
/usr/sbin/lofiadm [ file | device]
DESCRIPTION
lofiadm administers lofi, the loopback file driver. lofi
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 utilities for mount-
ing, checking or repairing file systems. See fsck(1M) and mount(1M).Use lofiadm to add a file as a loopback device, remove such
an association, or display information about the current associations.SunOS 5.11 Last change: 11 May 2010 1
System Administration Commands lofiadm(1M)
The number of potential lofi devices is limited by thezone.max-lofi rctl, which can be set by means of zonecfg(1M)
in the global zone. See resource_controls(5) for a descrip-
tion of zone.max-lofi.
Encryption and compression options are mutually exclusive on the command line. Further, an encrypted file cannot be compressed later, nor can a compressed file be encrypted later.In the global zone, lofiadm can be used on both the global
zone devices and all devices owned by other non-global zones
on the system. 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 reestablish a particular set of associations.-C {gzip | gzip-N | lzma}
Compress the file with the specified compression algo-
rithm. The gzip compression algorithm uses the same compressionas the open-source gzip command. You can specify the
gzip level by using the value gzip-N where N is 6 (fast)
or 9 (best compression ratio). Currently, gzip, withouta number, is equivalent to gzip-6 (which is also the
default for the gzip command).lzma stands for the LZMA (Lempel-Ziv-Markov) compression
algorithm. Note that you cannot write to a compressed file, nor can you mount a compressed file read/write.SunOS 5.11 Last change: 11 May 2010 2
System Administration Commands lofiadm(1M)
-d file | device
Remove an association by file or device name, if the associated block device is not busy, and deallocates the block device.-s segment_size
The segment size to use to divide the file beingcompressed. segment_size can be an integer multiple of
512.-U file
Uncompress a compressed file. The following options are used when the file is encrypted:-c crypto_algorithm
Select the encryption algorithm. The algorithm must bespecified when encryption is enabled because the algo-
rithm is not stored in the disk image.If none of -e, -k, or -T is specified, lofiadm prompts
for a passphrase, with a minimum length of eight charac-
ters, to be entered . The passphrase is used to derive asymmetric encryption key using PKCS#5 PBKD2.
-k raw_key_file | wrapped_key_file
Path to raw or wrapped symmetric encryption key. If aPKCS#11 object is also given with the -T option, then
the key is wrapped by that object. If -T is not speci-
fied, the key is used raw.-T token_key
The key in a PKCS#11 token to use for the encryption or
for unwrapping the key file.If -k is also specified, -T identifies the unwrapping
key, which must be an RSA private key.SunOS 5.11 Last change: 11 May 2010 3
System Administration Commands lofiadm(1M)
-e
Generate an ephemeral symmetric encryption key. OPERANDS The following operands are supported:crypto_algorithm
One of: aes-128-cbc, aes-192-cbc, aes-256-cbc, des3-cbc,
blowfish-cbc.
device Display the file name associated with the block device device.Without arguments, print a list of the current associa-
tions. Filenames must be valid absolute pathnames.When a file is added, it is opened for reading or writ-
ing by root. Any restrictions apply (such as restricted 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 bewritten to if the block device is only opened read-only.
Note that the filename might appear as a question mark (?) if it is not possible to resolve the path in the current context (for example, if it is an NFS path in anon-global zone).
file Display the block device associated with file.raw_key_file
Path to a file of the appropriate length, in bits, to use as a raw symmetric encryption key.token_key
PKCS#11 token object in the format:
token_name:manufacturer_id:serial_number:key_label
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System Administration Commands lofiadm(1M)
All but the key label are optional and can be empty. For example, to specify a token object with only its key label MylofiKey, use:-T :::MylofiKey
wrapped_key_file
Path to file containing a symmetric encryption keywrapped by the RSA private key specified by -T.
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/1lofiadm 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 Options/dev/lofi/1 /home/mike_s/RH6.0/sparc.iso -
SunOS 5.11 Last change: 11 May 2010 5
System Administration Commands lofiadm(1M)
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
# 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 nowcreate 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 OptionsSunOS 5.11 Last change: 11 May 2010 6
System Administration Commands lofiadm(1M)
Example 2 Mounting a Floppy Image This is similar to the first example. 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 are on does not have a floppy drive. It is also helpful if you do not 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 on an x86 platform:# 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 FileMaking a UFS filesystem on a file can be useful, particu-
larly if a test suite requires a scratch filesystem. It can be painful (or annoying) to have to repartition a disk just for the test suite, but you do not have to. You can newfs a file with lofi Create the file:# mkfile 35m /export/home/test
SunOS 5.11 Last change: 11 May 2010 7
System Administration Commands lofiadm(1M)
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
Example 4 Creating a PC (FAT) File System on a Unix File The following series of commands creates a FAT file system on a Unix file. The file is associated with a block devicecreated by lofiadm.
# mkfile 10M /export/test/testfs
# lofiadm -a /export/test/testfs
/dev/lofi/1 Note use of rlofi, not lofi, in following command.# mkfs -F pcfs -o nofdisk,size=20480 /dev/rlofi/1
Construct a new FAT file system on /dev/rlofi/1: (y/n)? y# mount -F pcfs /dev/lofi/1 /mnt
# cd /mnt
# df -k .
Filesystem kbytes used avail capacity Mounted on/dev/lofi/1 10142 0 10142 0% /mnt
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System Administration Commands lofiadm(1M)
Example 5 Compressing an Existing CD-ROM Image
The following example illustrates compressing an existingCD-ROM image (solaris.iso), verifying that the image is
compressed, and then uncompressing it.# lofiadm -C gzip /export/home/solaris.iso
Use lofiadm to attach a block device to it:
# lofiadm -a /export/home/solaris.iso
/dev/lofi/1 Check if the mapped image is compressed:# lofiadm
Block Device File Options /dev/lofi/1 /export/home/solaris.iso Compressed(gzip)/dev/lofi/2 /export/home/regular.iso -
Unmap the compressed image and uncompress it:# lofiadm -d /dev/lofi/1
# lofiadm -U /export/home/solaris.iso
Example 6 Creating an Encrypted UFS File System on a File This example is similar to the example of making a UFS filesystem on a file, above. Create the file:SunOS 5.11 Last change: 11 May 2010 9
System Administration Commands lofiadm(1M)
# mkfile 35m /export/home/test
Attach the file to a block device and specify that the file image is encrypted. As a result of this command, you obtain the character device, which is subsequently used by newfs:# lofiadm -c aes-256-cbc -a /export/home/secrets
Enter passphrase: My-M0th3r;l0v3s_m3+4lw4ys! (not echoed)
Re-enter passphrase: My-M0th3r;l0v3s_m3+4lw4ys! (not echoed)
/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, The mapped file system shows that encryption is enabled:# lofiadm
Block Device File Options /dev/lofi/1 /export/home/secrets Encrypted Mount and use the filesystem:# mount /dev/lofi/1 /mnt
# cp moms_secret_*_recipe /mnt
# ls /mnt
./ moms_secret_cookie_recipe moms_secret_soup_recipe
../ moms_secret_fudge_recipe moms_secret_stuffing_recipe
lost+found/ moms_secret_meatloaf_recipe moms_secret_waffle_recipe
# umount /mnt
# lofiadm -d /dev/lofi/1
Subsequent attempts to map the filesystem with the wrong key or the wrong encryption algorithm will fail:SunOS 5.11 Last change: 11 May 2010 10
System Administration Commands lofiadm(1M)
# lofiadm -c blowfish-cbc -a /export/home/secrets
Enter passphrase: mommy (not echoed)Re-enter passphrase: mommy (not echoed)
lofiadm: could not map file /root/lofi: Invalid argument
# lofiadm
Block Device File Options#
Attempts to map the filesystem without encryption will succeed, however attempts to mount and use the filesystem will fail:# lofiadm -a /export/home/secrets
/dev/lofi/1# lofiadm
Block Device File Options/dev/lofi/1 /export/home/secrets -
# mount /dev/lofi/1 /mnt
mount: /dev/lofi/1 is not this fstype#
ENVIRONMENT VARIABLES See environ(5) for descriptions of the following environmentvariables 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:SunOS 5.11 Last change: 11 May 2010 11
System Administration Commands lofiadm(1M)
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcs ||_____________________________|_____________________________|
SEE ALSO
fsck(1M), mount(1M), mount_ufs(1M), newfs(1M), zonecfg(1M),
attributes(5), resource_controls(5), lofi(7D), lofs(7FS)
NOTES Just as you would not directly access a disk device that hasmounted 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.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 canchange anything. The administrator can give users write-
access, allowing them to add or delete associations, but that is very likely a security hole and 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, likelogging or forcedirectio for UFS. For compatibility 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) might change in
future releases.SunOS 5.11 Last change: 11 May 2010 12