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squashfs

Compressed, read-only archive filesystem (SquashFS 4.0).

Implements filesystem.Filesystem. No cgo, no root.

Status

Read Write Format Label Symlinks On-disk format
✅ ✕ ✅ — ✅ SquashFS 4.0 read-only archive; gzip/xz/zstd/lzo/lz4 blocks + fragments

Supported

  • Superblock parse + validation (magic, version, block geometry)
  • Metadata-block reader crossing 8 KiB block boundaries
  • Inodes: basic + extended directory, regular file, symlink
  • Multi-header directory listings
  • File data: block list (compressed / uncompressed / sparse) + tail-end fragments
  • Path resolution following intermediate and final symlinks
  • Compression: gzip (zlib), xz (LZMA2), zstd, lzo (LZO1X), lz4, and uncompressed blocks
  • Image creation — BuildFromDir writes a SquashFS 4.0 image from a tree (gzip or uncompressed), readable by unsquashfs

Not implemented

  • In-place writes — the archive is immutable once written; mutators return ErrReadOnly. Writer omits tail-end fragment packing, xattrs, and non-zero uid/gid.
  • Legacy standalone lzma compression (ErrUnsupportedCompression); xz with BCJ filters
  • Extended attributes (xattr table)

Install

go get github.com/go-filesystems/squashfs

Note

See the module's README for full, up-to-date details.