dpp-py 0.1.3

Python bindings for parsing Apple DMG disk images, HFS+/APFS filesystems, PKG installers, and PBZX/CPIO payloads

dpp

Python bindings for the Apple DMG extraction pipeline

Open macOS .dmg disk images from Python — browse HFS+/APFS filesystems, extract .pkg installers, and unpack payloads.

Native Rust speed — powered by PyO3 bindings to the dpp Rust pipeline.

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Why dpp?

dpp is the only Python library that handles the entire Apple package extraction pipeline natively.

Without dpp, extracting files from a macOS .dmg in Python requires shelling out to multiple command-line tools — most of which only work on macOS.

Feature	dpp	hdiutil + shell	dmglib (Python)
Single API	✓	❌ (4+ tools)	partial
DMG read/write	✓	✓	read only
HFS+ support	✓	✓	❌
APFS support	✓	✓	❌
PKG extraction	✓	✓ (xar)	❌
PBZX/CPIO	✓	✓ (cpio)	❌
Cross-platform	✓	macOS only	partial
Native speed	✓	✓	❌

Features

Open DMG	Parse UDIF disk images with LZFSE/XZ/Zlib/Bzip2 compression
Browse HFS+/APFS	Auto-detect and navigate filesystems inside the DMG
Extract PKG	Open .pkg installers found on the volume
Unpack PBZX	Decompress XZ payloads and parse CPIO archives
Create DMG	Build DMG files with selectable compression
Create CPIO/PBZX	Build CPIO archives and PBZX payloads
Context managers	All reader/writer classes support with statements
Exception hierarchy	Structured errors that map to specific failure modes

Pipeline

                 ┌─────────┐
             ┌──▶│  HFS+   │──┐
┌─────────┐  │   │ (volume)│  │   ┌─────────┐    ┌─────────┐
│  UDIF   │──┤   └─────────┘  ├──▶│   XAR   │───▶│  PBZX   │
│  (DMG)  │  │   ┌─────────┐  │   │  (PKG)  │    │ (files) │
└─────────┘  └──▶│  APFS   │──┘   └─────────┘    └─────────┘
                 │ (volume)│
                 └─────────┘

Installation

pip install dpp-py

From source (development)

cd dpp-python
pip install maturin
maturin develop

Quick Start

Browse a DMG (auto-detect filesystem)

import dpp

with dpp.open("installer.dmg") as dmg:
    # List partitions
    for p in dmg.partitions:
        print(p.name, p.partition_type, p.size)

    # Open filesystem (auto-detects HFS+/APFS)
    with dmg.filesystem() as fs:
        print(fs.fs_type)       # "hfsplus" or "apfs"

        # Directory listing
        for entry in fs.list_directory("/"):
            print(entry.name, entry.kind, entry.size)

        # Read file contents
        data = fs.read_file("/some/file.txt")

        # File metadata
        stat = fs.stat("/some/file.txt")
        print(stat.size, stat.mode, stat.uid)

        # Walk entire filesystem
        for entry in fs.walk():
            print(entry.path, entry.kind)

Choose Extraction Mode

# In-memory mode: faster for small DMGs
with dpp.open("small.dmg") as dmg:
    fs = dmg.filesystem(mode="in_memory")

# Temp-file mode (default): low memory for large DMGs
with dpp.open("large.dmg") as dmg:
    fs = dmg.filesystem(mode="temp_file")

Extract a PKG Payload

with dpp.open("installer.dmg") as dmg:
    with dmg.filesystem() as fs:
        with fs.open_pkg("/path/to/package.pkg") as pkg:
            print(pkg.components)

            with pkg.payload("com.example.pkg") as payload:
                for f in payload.list():
                    print(f.path, f.size)
                data = payload.extract_file("./usr/bin/tool")

One-Call Extraction

# Find all .pkg files in a DMG
packages = dpp.find_packages("image.dmg")

# Extract a specific component payload in one call
archive = dpp.extract_pkg_payload(
    "image.dmg",
    "/path/to/installer.pkg",
    "com.apple.pkg.KDK",
)
for entry in archive.list():
    print(entry.path, entry.size)

Create DMG Files

builder = dpp.DmgBuilder()
builder.compression = "zlib"     # "raw", "zlib", "bzip2", "lzfse"
builder.compression_level = 6
builder.add_partition("disk image", partition_data)
builder.build("output.dmg")

Create CPIO/PBZX Archives

# Build CPIO content
cpio = dpp.CpioBuilder()
cpio.add_directory("./usr/bin", mode=0o755)
cpio.add_file("./usr/bin/hello", b"#!/bin/sh\necho hello\n", mode=0o755)
cpio.add_symlink("./usr/bin/hi", "./usr/bin/hello")
cpio_data = cpio.finish()

# Write PBZX archive
writer = dpp.PbzxWriter("output.pbzx", compression_level=6)
writer.write_cpio(cpio_data)
writer.finish()

Low-Level DMG Access

with dpp.DmgArchive.open("file.dmg") as archive:
    print(archive.stats)
    print(archive.compression_info)
    data = archive.extract_partition(0)
    archive.extract_partition_to(0, "/tmp/output.bin")

Standalone Filesystem Access

# Read raw partition images directly (no DMG wrapper)
with dpp.HfsVolume.open("partition.img") as vol:
    entries = vol.list_directory("/")
    data = vol.read_file("/some/file")

with dpp.ApfsVolume.open("apfs_partition.img") as vol:
    entries = vol.list_directory("/")

Documentation

API Reference	Full class and method documentation
Rust Library	Underlying Rust pipeline API
CLI Tool	dpp-tool for interactive DMG exploration

API Reference

Top-level Functions

Function	Description
dpp.open(path)	Open a DMG file, returns DmgPipeline
dpp.find_packages(path)	Find all .pkg files inside a DMG
dpp.extract_pkg_payload(dmg, pkg, component)	Extract a PKG payload in one call

Pipeline Classes

DmgPipeline — High-level entry point. Context manager.

Property/Method	Description
partitions	List of PartitionInfo
filesystem(mode=None)	Open filesystem, returns FilesystemHandle. Mode: "temp_file" (default) or "in_memory"

FilesystemHandle — Unified HFS+/APFS volume. Context manager.

Property/Method	Description
fs_type	"hfsplus" or "apfs"
volume_info	VolumeInfo metadata
list_directory(path)	List entries, returns list[DirEntry]
read_file(path)	Read file contents, returns bytes
stat(path)	File metadata, returns FileStat
walk()	Walk all entries, returns list[WalkEntry]
exists(path)	Check if path exists
open_pkg(path, streaming=False)	Open a .pkg file, returns PkgReader

DMG Classes

DmgArchive — Lower-level DMG access. Context manager.

Property/Method	Description
stats	DmgStats
compression_info	CompressionInfo
partitions	List of PartitionInfo
extract_partition(id)	Extract by ID, returns bytes
extract_partition_by_name(name)	Extract by name, returns bytes
extract_partition_to(id, path)	Extract to file
extract_main_partition()	Extract main partition, returns bytes

DmgBuilder — Create DMG files.

Property/Method	Description
compression	"raw", "zlib", "bzip2", or "lzfse"
compression_level	0–9
add_partition(name, data)	Add partition data
build(path)	Write DMG to disk

PKG/XAR Classes

PkgReader — macOS package reader. Context manager.

Property/Method	Description
is_product_package	Whether this is a distribution package
components	List of component names
distribution()	Distribution XML (if product package)
package_info(component)	PackageInfo XML
payload(component)	Extract payload, returns Archive
payload_bytes(component)	Raw payload bytes
list_files()	List all XAR file paths

XarArchive — XAR archive reader. Context manager.

Property/Method	Description
files	List of XarFile
find(path)	Find file by path
read_file(index)	Read file by index, returns bytes

Payload Classes

Archive — PBZX/CPIO payload reader. Context manager.

Property/Method	Description
list()	List entries, returns list[FileEntry]
extract_file(path)	Extract file, returns bytes
extract_all(dest)	Extract all to directory
decompressed_size	Size of decompressed CPIO data
cpio_data()	Raw CPIO bytes

CpioBuilder — Create CPIO archives.

Method	Description
add_file(path, content, mode=0o644)	Add a file
add_directory(path, mode=0o755)	Add a directory
add_symlink(path, target, mode=0o777)	Add a symlink
finish()	Finalize, returns bytes

PbzxWriter — Create PBZX archives.

Method	Description
write_cpio(data)	Write CPIO data
total_written	Bytes written so far
finish()	Finalize archive

Filesystem Classes

HfsVolume / ApfsVolume — Standalone volume readers for raw partition images. Context managers.

Method	Description
list_directory(path)	List entries
read_file(path)	Read file, returns bytes
stat(path)	File metadata
walk()	Walk all entries
exists(path)	Check path existence

Data Types

All data types are immutable (frozen) Python objects with __repr__.

Type	Fields
PartitionInfo	name, id, sectors, size, compressed_size, partition_type
DirEntry	name, kind, size
FileStat	fs_type, id, kind, size, uid, gid, mode, create_time, modify_time, nlink, data_fork_extents, resource_fork_size
VolumeInfo	fs_type, block_size, file_count, directory_count, name, symlink_count, total_blocks, free_blocks, version, is_hfsx
WalkEntry	path, name, kind, size
FileEntry	path, size, mode, mtime, uid, gid, is_dir, is_symlink, link_target
CompressionInfo	zero_fill_blocks, raw_blocks, zlib_blocks, bzip2_blocks, lzfse_blocks, xz_blocks, adc_blocks
DmgStats	version, sector_count, partition_count, total_uncompressed, total_compressed, data_fork_length, compression_ratio, space_savings
XarFile	id, name, path, file_type, size, compressed_size
ChunkInfo	index, offset, compressed_size, uncompressed_size, is_compressed, compression_ratio
ArchiveStats	chunk_count, compressed_size, uncompressed_size, file_count, directory_count, total_file_size, compression_ratio, space_savings

Exceptions

DppError (base)
├── IoError               # I/O errors
├── InvalidFormatError    # bad magic, corrupt data, invalid headers
├── FileNotFoundError     # file or partition not found
├── DecompressionError    # decompression failures
└── UnsupportedError      # unsupported features/formats

Example Output

>>> import dpp
>>> with dpp.open("Kernel_Debug_Kit.dmg") as dmg:
...     for p in dmg.partitions:
...         print(p)
PartitionInfo(name="MBR : 0", id=-1, size=512, type="Other")
PartitionInfo(name="Primary GPT Header : 1", id=0, size=512, type="Other")
PartitionInfo(name="Apple_HFSX : 3", id=2, size=1069593600, type="Hfsx")

>>> with dpp.open("Kernel_Debug_Kit.dmg") as dmg:
...     with dmg.filesystem() as fs:
...         print(fs.fs_type)
...         for e in fs.list_directory("/"):
...             print(e)
hfsplus
DirEntry(name="Library", kind="directory", size=0)
DirEntry(name=".DS_Store", kind="file", size=6148)

>>> builder = dpp.DmgBuilder()
>>> builder.compression = "zlib"
>>> builder.add_partition("test", b"\x00" * 4096)
>>> builder.build("/tmp/test.dmg")
>>> with dpp.DmgArchive.open("/tmp/test.dmg") as a:
...     print(a.stats)
DmgStats(partitions=1, uncompressed=4096, compressed=30, ratio=0.01)

Alternatives

Approach	DMG	HFS+	APFS	PKG	PBZX	Cross-platform	Language
dpp	✓	✓	✓	✓	✓	✓	Python (Rust native)
hdiutil + subprocess	✓	✓	✓	✓	✓	macOS only	Python + shell
dmglib	partial	❌	❌	❌	❌	✓	Python
dpp Rust library	✓	✓	✓	✓	✓	✓	Rust

Choose dpp if you need:

• End-to-end DMG → files extraction from Python on any platform
• Native speed without subprocess overhead
• Structured API instead of shell pipelines
• Both read and write capabilities

Next Steps

• Type stubs — .pyi stub files for full IDE autocompletion
• Async support — async wrappers for I/O-heavy operations
• Iterator protocol — lazy iteration for walk() and list()
• Progress callbacks — report extraction progress
• Wheels — pre-built wheels for common platforms

License

MIT