Test Case: MicroLZMA Consumption and Corruption

Test ID: TC144-microlzma-consumption-and-corruption

G5 fixture contract: Use G5-MANUAL-SETUP.md. Its generated paths, source comparisons, structured corruption offsets, and cleanup rules supersede placeholder examples in this file. Category: Compression Priority: Critical Regression: MicroLZMA full/partial completion semantics

Objective

Verify MicroLZMA input-consumption rules for complete streams, early-success rules for partial references, and deterministic rejection of damaged streams.

Preconditions

FreeBSD 15 guest and repo22 module.
A full-index LZMA image with:
- /a.dat: 1048576-byte complete MicroLZMA stream;
- /b.dat: 700000-byte partial reference to /a.dat's pcluster;
- the /b.dat HEAD record marked Z_EROFS_LI_PARTIAL_REF.
- the reused pblk and D0_CBLKCNT both equal /a.dat's values.
A corrupted copy with a byte changed inside the proven compressed byte range.
Source files and their SHA256 values available on the guest.

Test Steps

Prove the pcluster and partial-reference record with dump.erofs and a byte-level parser.
Mount the valid image and hash /a.dat completely.
Hash /b.dat completely; this requests only a prefix of the reused stream.
Compare reads at offsets 65500 and 524287 against source bytes.
Mount the corrupted image and read /a.dat with an errno-reporting helper.
Confirm the implementation's complete-stream condition includes both XZ_STREAM_END and buffer.in_pos == srclen.
Compare vmstat -m active EROFS allocations and pre/post dmesg.

Expected Results

/a.dat succeeds only after exact output, XZ_STREAM_END, and complete compressed-input consumption.
/b.dat accepts XZ_OK after the requested partial output is filled.
Both complete SHA256 values and random ranges match.
The corrupted full stream returns errno 5 (EIO).
control.bin in the same corrupted image still matches its source.
Decoder state is freed on success and error; active EROFS allocations return to zero after unmount/unload.

Cleanup

umount /mnt/repo22 2>/dev/null || true
mdconfig -d -u "${unit#md}" 2>/dev/null || true
kldunload -i "${module_id}"

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