UDFINFO

Section: User Commands (1)
Updated: udftools
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NAME

udfinfo --- show information about UDF filesystem

SYNOPSIS

udfinfo [ options ] device

DESCRIPTION

udfinfo shows various information about a UDF filesystem stored either on the block device or in the disk file image. The output from the udfinfo is suitable for parsing by external applications or scripts.

OPTIONS

-h,--help

Display the usage and the list of options.

-b,--blocksize= block-size

Specify the size of blocks in bytes. Valid block size for a UDF filesystem is a power of two in the range from 512 to 32768 and must match a device logical (sector) size. If omitted, udfinfo tries to autodetect block size. First it tries logical (sector) size and then all valid block sizes.

--vatblock= vat-block

Specify the block location of the Virtual Allocation Table. Virtual Allocation Table is present only on UDF disks with Virtual Partition Map and must be at the last written/recorded disk block.

If omitted, udfinfo for optical disc tries to detect the last recorded block with fallback to the last block of block device or disk file image. In most cases, this fallback does not have to work and for disk file images with Virtual Allocation Table is necessary to specify the correct location.

Virtual Allocation Table contains locations of UDF disk blocks needed to read data storage, determinate used and free space blocks, read File Set Identifier and calculate Windows-specific Volume Serial Number. Also, it contains Logical Volume Identifier and overwrite previously stored in Logical Volume Descriptor.

--locale

Encode UDF string identifiers on output according to current locale settings (default).

--u8

Encode UDF string identifiers on output to 8-bit OSTA Compressed Unicode format without leading Compression ID byte, which is equivalent to Latin1 (ISO-8859-1). This will work only for strings which Unicode code points are below U+100.

--u16

Encode UDF string identifiers on output to 16-bit OSTA Compressed Unicode format without leading Compression ID byte, which is equivalent to UTF-16BE.

--utf8

Encode UDF string identifiers on output to UTF-8.

EXIT STATUS

udfinfo returns 0 if successful, non-zero if there are problems like a block device does not contain UDF filesystem.

OUTPUT FORMAT

First part of the udfinfo standard output contains information in key=value format. List of all keys with their meaning are in the following table:

filename: File name of the selected block device or disk file image
label: label is an alias for lvid, see udflabel(8) section UDF LABEL AND UUID
uuid: UUID are first 16 hexadecimal lowercase digits of fullvsid, but see udflabel(8) section UDF LABEL AND UUID
lvid: UDF Logical Volume Identifier stored in UDF Logical Volume Descriptor
vid: UDF Volume Identifier stored in UDF Primary Volume Descriptor
vsid: fullvsid after uuid part, typically 17.-127. character
fsid: UDF File Set Identifier stored in UDF File Set Descriptor
fullvsid: UDF Volume Set Identifier stored in UDF Primary Volume Descriptor
winserialnum: Windows-specific Volume Serial Number
blocksize: UDF block size
blocks: Number of all blocks on the selected block device or disk file image
usedblocks: Number of used space blocks on UDF disk for data storage
freeblocks: Number of free space blocks on UDF disk for data storage
behindblocks: Number of blocks which are behind the last block used by UDF disk
numfiles: Number of stored files on UDF disk
numdirs: Number of stored directories on UDF disk
udfrev: UDF revision needed for reading UDF disk
udfwriterev: UDF revision needed for writing or modifying UDF disk
vatblock: UDF block location of the Virtual Allocation Table (visible only when available)
integrity: UDF integrity of Logical Volume, one of: opened, closed, unknown
accesstype: UDF Access Type, one of: overwritable, rewritable, writeonce, readonly, pseudo-overwritable, unknown
softwriteprotect: Status of UDF SoftWriteProtect flag, either yes or no (available since udfinfo 2.2)
hardwriteprotect: Status of UDF HardWriteProtect flag, either yes or no (available since udfinfo 2.2)

When UDF integrity is not closed it means that the UDF disk was not properly unmounted, is in an inconsistent state and needs repairing.

When either softwriteprotect or hardwriteprotect flag is set then UDF disk should be treated as read-only.

All UDF string identifiers are stored on UDF disk in Unicode, therefore they are locale or code page agnostic. Options --locale, --u8, --u16 and --utf8 controls how are identifiers encoded on output.

All newline characters from the UDF string identifiers are removed, so it is guaranteed that the newline character is present only as a separator.

Second part of the udfinfo standard output contains list of UDF block types stored on device, one per line in the following format:

: start=block-num, blocks=block-count, type=block-type

With meaning that block-type starts at UDF block block-num and span block-count blocks on device.

Windows-specific Volume Serial Number is a non-standard 32-bit checksum, calculated as four separate 8-bit XOR checksums of 512 bytes long UDF File Set Descriptor. Therefore, it cannot be set or changed as opposed to UUID which is 64-bit long. This non-standard checksum is used only by Windows systems (since Windows 98 era when it was introduced) and can be displayed on Windows systems by applications like vol, dir or fsutil.exe.

LIMITATIONS

udfinfo prior to version 2.2 was unable to print Unicode strings with code points above U+FFFF correctly.

udfinfo prior to version 2.2 was unable to read Metadata Partition. Therefore, determining used and free space blocks, reading File Set Identifier and calculating Windows-specific Volume Serial Number did not have to be available or correctly calculated for disks with UDF revisions higher than 2.01 which had Metadata Partition.

udfinfo prior to version 2.1 was unable to read Virtual Allocation Table stored outside of Information Control Block. Therefore above limitation applied also for some Write Once media.

AUTHOR

Pali Rohár <pali.rohar@gmail.com>

AVAILABILITY

udfinfo is part of the udftools package since version 2.0 and is available from https://github.com/pali/udftools/.