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libsqfs
Programmatic SquashFS 4 image construction
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libsqfs is a C library for programmatically creating SquashFS 4 images. It allows callers to compose directories, regular files, symbolic links, device nodes, FIFOs, ownership and extended attributes without first materializing that tree on a local filesystem. Image construction can use multiple worker threads.
The library is used by Abuild as its native SquashFS writer.
The original repository was hosted at https://gitorious.org/libsqfs/libsqfs.git. Gitorious is no longer available, and no newer authoritative upstream has been found. This repository therefore preserves the recovered upstream history and maintains the version used by Abuild.
| Branch | Purpose |
|---|---|
master | Immutable archive of the last known upstream commit, c5c464b |
abuild | Maintained Abuild dependency, including Zstd and current-toolchain fixes |
abuild-gh | GitHub-only CI, provenance checks and Pages on top of abuild |
The recovered upstream is independently preserved by Software Heritage in snapshot 48285f2d8cf74bc14b1c5d300ed5bfccbd2fbc4f. The scheduled provenance workflow checks that the archived snapshot still identifies c5c464b as its master tip; it does not claim that a live upstream still exists.
The configured build enables the compressors whose development libraries are available:
On Debian Trixie, install a C toolchain, Autoconf, Automake, Libtool, pkg-config, and the development packages for zlib, liblzma and libzstd. Then run:
The maintained test suite covers image options, empty images, regular and special files, directory layout, extended attributes, compound data items and the public Zstd interface. The GitHub workflow additionally runs the suite with AddressSanitizer, LeakSanitizer and UndefinedBehaviorSanitizer, and checks a Zstd-compressed image with the distribution's independent unsquashfs reader. It also publishes an informative HTML source-coverage report. The report retains zero-count data for compiled sources that no test executes; no coverage threshold is enforced.
Build the API documentation with:
The generated HTML starts at doc/index.html.
SquashFS is a compressed read-only filesystem originally created by Phillip Lougher. A generated image can be mounted by the Linux kernel or inspected with the squashfs-tools utilities. Compared with the command-line mksquashfs tool, libsqfs is useful when an application needs precise control over metadata, needs to synthesize content on demand or cannot represent the intended image tree on the host filesystem.
The library currently does not append to existing SquashFS images or represent sparse files.
libsqfs is distributed under the GNU General Public License, version 2 or (at your option) any later version. See the license text.
The original implementation was written by Helge Bahmann at secunet Security Networks AG. The Git history records subsequent contributors and the Abuild-specific maintenance history.
1.9.8