TapTap
1042d15db7
- --delete-delay: state that the reported count advances on actual removal while --max-delete is charged at plan/snapshot time (defer_add/planned). A new differential shows rsync instead charges on actual removals and recursively removes a queued directory, so the row moves to Caveat (matrix 111/13/33) and the residual is pinned by tests. - Add a deterministic unit test (plan-time budget charge), a FastSync integration test (byte-barrier refill + --max-delete), and an rsync differential for a refilled deferred directory. - Soften the --fuzzy summary: the tree is byte-exact by design, so it is pinned by the threshold suite, not a byte-level differential. - README: describe what -m parity actually selects; fix the allowlist example to the real max_delete entry. - xdist-safe delete-timing fixture names (timing and --threads mode). - Renumber the duplicate HANDOFF item 9 to 10; add the missing final newline to test_checksum.c. - Expose ignore_errors_allows_delete and unit-test the deletion gate without a privileged source directory; update the stale deleted-count doc comment. No production behavior changes.
108 lines
9.9 KiB
Markdown
108 lines
9.9 KiB
Markdown
# FastSync — Session Handoff (2026-09-17)
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## Current status
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- **Release `v2.21.0`** tagged (`919a729`, "Release v2.21.0"); full CI green
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(run 552: lint, build-and-test, ASan, UBSan, fuzz-build, coverage, valgrind).
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`dev` has the release commit plus later doc-only merges (a README refresh and
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this handoff).
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- **Release PR #284 (`dev` -> `main`)** open, CI green (run 553).
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`main` is protected: it needs review/approval to merge.
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https://gitea.tap-tap.win/TapTap/FastSync/pulls/284
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- **`PROTOCOL_VERSION` = `"2.27.0"`** (`src/shared/config.h`); CMake
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`project(FastFileTransfer VERSION 2.27.0)`.
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- Working tree clean; no wave worktrees remain.
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## What landed this session
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1. **Wave 8 (refactors):** Config X-macro wire table; single-owner `authorized_root`;
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daemon per-module/per-host caps + cross-process auth lockout (`daemon_limits.[ch]`);
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`Data` charge returns to its owning `ProtocolSession`.
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2. **Wave 9 (protocol 2.21.0):** optional `STATUS_ERROR_DETAIL` rejection reasons;
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server-contacting `--dry-run` (`STATUS_DRY_RUN_TRANSFER`, receiver mutates nothing).
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3. **Security wave:** ran 5 parallel audits (wire parsing; daemon/transport/TLS/auth;
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receiver confinement; client/CLI/SSH; crypto/memory/limits). Fixed all HIGH and the
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confirmed MEDIUMs:
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- SSH `-o ProxyCommand=…` argument injection (RCE) — reject leading `-`, insert `--`.
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- Truncated zstd frame infinite CPU loop (remote DoS).
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- FIFO receiver opens lacked `O_NONBLOCK` (indefinite hang).
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- `--inplace` could write a FIFO/device (bypass of `--write-devices` gate).
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- `--force` not gated by server `--allow-delete`.
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- Privileged standalone server defaulted super activities on; added `--allow-super`
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(never honored with `--stdio`).
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- `--dry-run` content/hash oracle on `read only`/basis files removed.
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- Empty `hosts allow`/`deny`/`auth users` now rejected.
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- TLS: AEAD-only 1.2 + server preference, TOCTOU-safe key load, IP-SAN verify,
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CN-truncation guard. Glob backtracking bounded; line reads bounded; ACL xattrs
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gated on `--acls`; decompression/chunk memory charged; pre-auth `basis_count`
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NULL-deref fixed.
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4. **Tooling:** benchmark accuracy (data mix, verification, percentiles, `tc`,
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`build-bench/`, `--warm` mode); `shell.nix` full toolchain and no build-on-entry;
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docs state push-only / remote-source unsupported.
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5. **Preserve-attribute split (protocol 2.22.0)** landed on `feat/preserve-attr-split`: per-attribute `-p/-t/-o/-g` + `--no-*` negations, `-a` = `-rlptgoD`, and the 2.21.0 → 2.22.0 wire bump.
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6. **Rsync-parity wave (protocol 2.23.0)** on `feat/rsync-parity`: rsync short options/clustering/attached values (`-r`/`-b`/`-L`/`-B`, `-av`, `-aAX`, `-B1000`, `-essh`, `-MOPT`), `-c` checksum quick-check, `--checksum-choice`/`--compress-choice` validation and seed randomization, rsync timeout/max-alloc defaults, temp-dir confinement + `EXDEV` fallback, ownership/mapping parity (numeric-ids modifier, map ranges/`*`/empty-FROM, `--chown`+map conflicts, fake-super resolved-owner record), verbatim symlink storage with rsync `--safe-links`/`--munge-links`, socket recreation under `--specials`, `--chmod` 3.4.1 semantics, and delete scoping + `--max-delete` partial/exit-25. Wire: appended delete-manifest synchronized-directory section and `STATUS_DELETE_LIMIT`.
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7. **Parity-completion wave (protocol 2.24.0 → 2.26.0)** on `feat/parity-completion`: per-directory delete plans (`STATUS_DELETE_PLAN`) for `--delete-during`/`--delete-delay`; receiver `STATUS_STATS` counters feeding `--stats`/`--progress` and `--out-format %b/%c/%C`, plus `-n --delete` lines; `lz4`/`zlib`/`zlibx` compression and `md4`/`sha1`/`none` checksums with `auto` negotiation (default `xxh128`/`zstd`); general `-R`/`--no-implied-dirs`/`-d`; the full filter grammar (`merge`/`dir-merge`/`hide`/`show`/`protect`/`risk`/`clear` + modifiers) and corrected `-F`/`-FF`; receiver-side `--chown`/map TO-name resolution; absolute basis dirs + `--link-dest` relink; receiver-side `--ignore-existing` short-circuit; `--preallocate` over `--sparse` via `fallocate(2)`; `--iconv=.`/`-`/`--no-iconv`; lone `-h` help; aliases `--ignore-non-existing`/`--protect-args`/`--msgs2stderr`; and the full `--info`/`--debug` vocabulary. `RSYNC_COMPAT.md` reclassifies the matrix to 106 ✅ / 27 ⚠️ / 23 ❌; the later rsync-parity-stats pass (`fix/parity-stats`) moves it to 107 ✅ / 25 ⚠️ / 24 ❌ (see item 8).
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8. **rsync-parity-stats pass** on `fix/parity-stats` (no wire change, `PROTOCOL_VERSION` stays `2.26.0`): `--delete-delay` now reports only entries it actually removes, while the `--max-delete` budget is charged at plan/snapshot time (`planned`, via `defer_add`) to bound the deferred list (a refilled deferred directory that survives `ENOTEMPTY` is not reported but still consumes budget); `--stats` gained the `(reg/dir/link/special)` `Number of files` breakdown and now counts only regular files actually stored for `Number of regular files transferred`/transferred size/literal data (up-to-date re-runs report 0); `Total file size` includes symlink target lengths; `--progress` prints the leading `./` root line and counts it in `to-chk` so a single-file transfer matches rsync; and `%C` uses the selected transfer checksum with `checksum_digest_file` supporting md4/sha1/none, byte-identical to rsync for every algorithm. `--out-format` reclassified ❌ (`%b`/delta-`%c` are protocol-specific). Differential + regression tests added; full suite + ASan + clang-format + cppcheck clean.
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9. **Option-parity wave (protocol 2.26.0 → 2.27.0, on `fix/parity-options`):**
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`--bwlimit` now ports rsync 3.4.1's units/quantization and paces like its
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leaky bucket; `--ignore-errors` reproduces rsync's default (an I/O error
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skips deletion unless the flag is set; the readable tree still transfers and
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the run exits 23) across every delete timing; the `--info` categories with a
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FastSync event (`name`/`flist`/`del`/`remove`/`nonreg`/`progress`) emit
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rsync's line format, with real-run `deleting`/`*deleting` lines carried over
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the new trailing config bool `report_deletes` (golden wire updated by
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`tests/test_config.c`). Two residuals were reclassified **divergent**: `-M`
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over daemon/TCP (no argv channel in FastSync's binary config handshake;
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rsync-daemon differential pins the rsync behavior) and receiver-side
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`protect`/`risk` re-derivation for destination-only entries (would need a
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receiver filter engine; differential pins the divergence). The options pass
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stands at **110 ✅ / 21 ⚠️ / 26 ❌**. New `tests/integration/test_option_parity.py`
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holds the rsync differentials (bwlimit parse+rate, info lines, real-setpriv
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`--ignore-errors`, rsync-daemon `-M`, filter-protect pin).
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10. **rsync-parity-fs pass** on `fix/parity-fs` (no wire change of its own; integrated
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on top of the 2.27.0 options wave): recursive transfers now recreate empty source directories (and
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`-m/--prune-empty-dirs` still suppresses them), a directory entry replaces a
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blocking destination regular file, and `-R --no-implied-dirs --files-from`
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places a listed file under a missing implied parent with default attributes
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instead of refusing (real rsync 3.4.1 parity, differential-tested). `--iconv`
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now reproduces rsync's push direction (destination charset = the spec's REMOTE
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half; a server `--iconv` overrides), and `-T/--temp-dir` relative semantics are
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confirmed identical while the absolute-path confinement is a deliberate
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divergence. The basis-dir options, `--delay-updates` and `--dry-run` were
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reclassified to ❌ after a differential test reproduced each exact residual
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(basis content verification, fixed staging-name collision, and dry-run
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would-delete over-report). `--fuzzy` was also reclassified to ❌ (deterministic
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heuristic with a 10× size window, not rsync's matcher), but its residual is the
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candidate-selection heuristic itself: the final tree is byte-exact by design, so
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it is pinned by the `TestFuzzy` threshold suite rather than a byte-level rsync
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differential. The parity-review pass then moved `--delete-delay` to ⚠️ (the
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plan-time `--max-delete` charge and non-recursive deferred removal differ from
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rsync when a snapshotted entry fails removal). Differential-gate allowlist
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entries `min_size`/`empty_dirs_recursive`/`dirs_plain` were removed. The
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integrated stats+options+fs branch stands at **111 ✅ / 13 ⚠️ / 33 ❌ = 157**;
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full suite + ASan + clang-format + cppcheck clean.
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## Next steps
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1. **Merge PR #284** (`dev` -> `main`) once reviewed (protected branch).
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2. **Deferred security items** (documented, not implemented):
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- Pre-auth config/daemon-auth handshake has no aggregate wall-clock deadline
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(per-message timeout only) — slowloris holds connection slots.
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- Per-source registry fails open when the shared table is full (per-module/global
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caps and host ACLs still apply); consider fail-closed or larger/evicting table.
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- SCRAM-like daemon auth has no TLS channel binding (and is not RFC 5802).
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- `cleanup()` signal handler calls non-async-signal-safe teardown; daemon `umask(0)`.
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- Wire protocol assumes homogeneous word size/endianness (lengths are native
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`size_t`) — document or move to fixed-width framing.
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3. **Out of scope / intentional:** pull (remote source) mode is **not** planned —
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FastSync is push-only; see `RSYNC_COMPAT.md#direction`.
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## Key facts / commands
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- CI image: `gitea.tap-tap.win/taptap/fastsync-ci:v11` (alias `fastsync-ci:local`).
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- Build/test: `cmake -B build -S . -DSTRICT_WARNINGS=ON && cmake --build build -j$(nproc) && ./build/tests`
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then `python3 -m pytest tests/integration/ -n 4 --dist=load -m "not setpriv"`.
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- Dev shell: `nix-shell` (provides clang-format, cppcheck, pytest-xdist, openssh,
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rsync, iproute2, valgrind, lcov; does not build on entry).
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- Gitea API token: supplied out-of-band via the `TOKEN` environment variable; it is
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intentionally **not** recorded in this file.
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- CI polling: `GET /api/v1/repos/TapTap/FastSync/actions/runs?limit=N`, match `head_sha`,
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then `/actions/runs/<id>/jobs`.
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