$ npm install --save udif
var UDIF = require( 'udif' )
var dmg = new UDIF.Image( 'path/to/image.dmg' )
dmg.open( function( error ) {
// ...
})
dmg.close( function( error ) {
// ...
})
Note that the image has to be opened to determine the uncompressed size, as this is read from the resource fork.
UDIF.getUncompressedSize( 'path/to/image.dmg', function( error, size ) {
console.log( size, 'bytes' )
// > 629145600 bytes
})
var dmg = new UDIF.Image( 'path/to/image.dmg' )
dmg.open( function( error ) {
console.log( dmg.getUncompressedSize(), 'bytes' )
// > 629145600 bytes
})
var readableStream = UDIF.createReadStream( 'path/to/image.dmg' )
Or, if you already have an instance of UDIF.Image:
var readableStream = dmg.createReadStream()
Extracting the uncompressed, raw disk image from a .dmg file becomes as easy as the following:
UDIF.createReadStream( 'path/to/image.dmg' )
.pipe( fs.createWriteStream( '/path/to/destination.img' ) )
var sparseStream = UDIF.createSparseReadStream( 'path/to/image.dmg' )
Sparse readstreams are in objectMode and will emit objects of the shape { buffer, position }.
This means you'll need a writable stream that is also in objectMode and knows how to handle these.
For the sake of brevity, the following example only demonstrates passing a chunk's properties to fs.write();
sparseStream.on( 'data', function( chunk ) {
fs.writeSync( fd, chunk.buffer, 0, chunk.buffer.length, chunk.position )
})
var dmg = new UDIF.Image( 'https://github.com/resin-io/etcher/releases/download/v1.2.0/Etcher-1.2.0.dmg', {
fs: new HttpFs()
})
dmg.open( function( error ) {
// ...
})
The footer (aka the "Koly Block") contains pointers to the XML metadata, data fork & resource fork as well as checksums.
// Once the dmg has been opened:
dmg.open( function( error ) {
console.log( dmg.footer )
})
KolyBlock {
signature: 1802464377,
version: 4,
headerSize: 512,
flags: 1,
runningDataForkOffset: 0,
dataForkOffset: 0,
dataForkLength: 6585140266,
resourceForkOffset: 0,
resourceForkLength: 0,
segmentNumber: 1,
segmentCount: 1,
segmentId: <Buffer 18 66 9e 31 fa 6 d 4 f 7 d aa d0 f2 50 12 8 f 49 54>,
dataChecksum: Checksum { type: 2, bits: 32, value: 'c2208200' },
xmlOffset: 6585140266,
xmlLength: 1752206,
reserved1: <Buffer 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ...>,
checksum: Checksum { type: 2, bits: 32, value: '3f40bb47' },
imageVariant: 1,
sectorCount: 15178432,
reserved2: 0,
reserved3: 0,
reserved4: 0,
}
The XML data is a Property List, (or plist) which contains a block map under resource-fork.blkx.
dmg.open( function( error ) {
console.log( dmg.resourceFork )
})
{
blkx: [{
id: -1,
attributes: 80,
name: 'Driver Descriptor Map (DDM : 0)',
coreFoundationName: 'Driver Descriptor Map (DDM : 0)',
map: BlockMap {
signature: 1835627368,
version: 1,
sectorNumber: 0,
sectorCount: 1,
dataOffset: 0,
buffersNeeded: 520,
blockDescriptorCount: 0,
reserved1: 0,
reserved2: 0,
reserved3: 0,
reserved4: 0,
reserved5: 0,
reserved6: 0,
checksum: Checksum { type: 2, bits: 32, value: '698a85ed' },
blockCount: 2,
blocks: [
Block {
type: 2147483653,
description: 'UDZO (zlib-compressed)',
comment: '',
sectorNumber: 0,
sectorCount: 1,
compressedOffset: 0,
compressedLength: 22
},
Block {
type: 4294967295,
description: 'TERMINATOR',
comment: '',
sectorNumber: 1,
sectorCount: 0,
compressedOffset: 22,
compressedLength: 0
}
]
}
}, {
id: 0,
attributes: 80,
name: 'WINDOWSSUPPORT (Apple_ISO : 1)',
coreFoundationName: 'WINDOWSSUPPORT (Apple_ISO : 1)',
map: BlockMap {
signature: 1835627368,
version: 1,
sectorNumber: 1,
sectorCount: 3,
dataOffset: 0,
buffersNeeded: 520,
blockDescriptorCount: 1,
reserved1: 0,
reserved2: 0,
reserved3: 0,
reserved4: 0,
reserved5: 0,
reserved6: 0,
checksum: Checksum { type: 2, bits: 32, value: '6c1ce17e' },
blockCount: 2,
blocks: [
Block {
type: 2147483653,
description: 'UDZO (zlib-compressed)',
comment: '',
sectorNumber: 0,
sectorCount: 3,
compressedOffset: 22,
compressedLength: 24
},
Block {
type: 4294967295,
description: 'TERMINATOR',
comment: '',
sectorNumber: 3,
sectorCount: 0,
compressedOffset: 46,
compressedLength: 0
}
]
}
}, {
id: 1,
attributes: 80,
name: 'Apple (Apple_partition_map : 2)',
coreFoundationName: 'Apple (Apple_partition_map : 2)',
map: BlockMap {
signature: 1835627368,
version: 1,
sectorNumber: 4,
sectorCount: 60,
dataOffset: 0,
buffersNeeded: 520,
blockDescriptorCount: 2,
reserved1: 0,
reserved2: 0,
reserved3: 0,
reserved4: 0,
reserved5: 0,
reserved6: 0,
checksum: Checksum { type: 2, bits: 32, value: '115fc68e' },
blockCount: 2,
blocks: [
Block {
type: 2147483653,
description: 'UDZO (zlib-compressed)',
comment: '',
sectorNumber: 0,
sectorCount: 60,
compressedOffset: 46,
compressedLength: 358
},
Block {
type: 4294967295,
description: 'TERMINATOR',
comment: '',
sectorNumber: 60,
sectorCount: 0,
compressedOffset: 404,
compressedLength: 0
}
]
}
}, {
id: 2,
attributes: 80,
name: 'Macintosh (Apple_Driver_ATAPI : 3)',
coreFoundationName: 'Macintosh (Apple_Driver_ATAPI : 3)',
map: BlockMap {
signature: 1835627368,
version: 1,
sectorNumber: 64,
sectorCount: 2020420,
dataOffset: 0,
buffersNeeded: 520,
blockDescriptorCount: 3,
reserved1: 0,
reserved2: 0,
reserved3: 0,
reserved4: 0,
reserved5: 0,
reserved6: 0,
checksum: Checksum { type: 2, bits: 32, value: 'b2bb86f8' },
blockCount: 3948,
blocks: [
Block {
type: 2147483653,
description: 'UDZO (zlib-compressed)',
comment: '',
sectorNumber: 0,
sectorCount: 512,
compressedOffset: 404,
compressedLength: 25147
},
Block {
type: 2147483653,
description: 'UDZO (zlib-compressed)',
comment: '',
sectorNumber: 512,
sectorCount: 512,
compressedOffset: 25551,
compressedLength: 29149
},
... more items
]
}
}, {
id: 3,
attributes: 80,
name: ' (Apple_Free : 4)',
coreFoundationName: ' (Apple_Free : 4)',
map: BlockMap {
signature: 1835627368,
version: 1,
sectorNumber: 2020484,
sectorCount: 4,
dataOffset: 0,
buffersNeeded: 0,
blockDescriptorCount: 4,
reserved1: 0,
reserved2: 0,
reserved3: 0,
reserved4: 0,
reserved5: 0,
reserved6: 0,
checksum: Checksum { type: 2, bits: 32, value: '00000000' },
blockCount: 2,
blocks: [
Block {
type: 2,
description: 'FREE (unallocated)',
comment: '',
sectorNumber: 0,
sectorCount: 4,
compressedOffset: 984141554,
compressedLength: 0
},
Block {
type: 4294967295,
description: 'TERMINATOR',
comment: '',
sectorNumber: 4,
sectorCount: 0,
compressedOffset: 984141554,
compressedLength: 0
}
]
}
}, {
id: 4,
attributes: 80,
name: 'Mac_OS_X (Apple_HFS : 5)',
coreFoundationName: 'Mac_OS_X (Apple_HFS : 5)',
map: BlockMap {
signature: 1835627368,
version: 1,
sectorNumber: 2020488,
sectorCount: 13157944,
dataOffset: 0,
buffersNeeded: 520,
blockDescriptorCount: 5,
reserved1: 0,
reserved2: 0,
reserved3: 0,
reserved4: 0,
reserved5: 0,
reserved6: 0,
checksum: Checksum { type: 2, bits: 32, value: '39ce04b6' },
blockCount: 25387,
blocks: [
Block {
type: 2147483646,
description: 'COMMENT',
comment: '+beg',
sectorNumber: 0,
sectorCount: 0,
compressedOffset: 984141554,
compressedLength: 0
},
Block {
type: 2147483653,
description: 'UDZO (zlib-compressed)',
comment: '',
sectorNumber: 0,
sectorCount: 512,
compressedOffset: 984141554,
compressedLength: 1812
},
... more items
]
}
}],
cSum: [{
Attributes: '0x0000',
Data: <Buffer 01 00 02 00 00 00 00 00 00 00>,
ID: '0',
Name: null
}, {
Attributes: '0x0000',
Data: <Buffer 01 00 02 00 00 00 10 fc a8 3f>,
ID: '1',
Name: null
}, {
Attributes: '0x0000',
Data: <Buffer 01 00 02 00 00 00 10 37 71 ef>,
ID: '2',
Name: null
}],
nsiz: [{
Attributes: '0x0000',
Data: <Buffer 3 c 3 f 78 6 d 6 c 20 76 65 72 73 69 6 f 6e 3 d 22 31 2e 30 22 20 65 6e 63 6 f 64 69 6e 67 3 d 22 55 54 46 2 d 38 22 3 f 3e 0 a 3 c 21 44 4 f 43 54 59 50 45 20 70 ...>,
ID: '0',
Name: null
}, {
Attributes: '0x0000',
Data: <Buffer 3 c 3 f 78 6 d 6 c 20 76 65 72 73 69 6 f 6e 3 d 22 31 2e 30 22 20 65 6e 63 6 f 64 69 6e 67 3 d 22 55 54 46 2 d 38 22 3 f 3e 0 a 3 c 21 44 4 f 43 54 59 50 45 20 70 ...>,
ID: '1',
Name: null
}, {
Attributes: '0x0000',
Data: <Buffer 3 c 3 f 78 6 d 6 c 20 76 65 72 73 69 6 f 6e 3 d 22 31 2e 30 22 20 65 6e 63 6 f 64 69 6e 67 3 d 22 55 54 46 2 d 38 22 3 f 3e 0 a 3 c 21 44 4 f 43 54 59 50 45 20 70 ...>,
ID: '2',
Name: null
}],
plst: [{
Attributes: '0x0050',
Data: <Buffer 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ...>,
ID: '0',
Name: null
}],
size: [{
Attributes: '0x0000',
Data: <Buffer 05 00 01 00 00 00 00 60 8 c 91 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ...>,
ID: '2',
Name: null
}]
}
FAQs
Apple Universal Disk Image Format (UDIF/DMG)
We found that udif demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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