BLOCKER: an absent mirror whose PARENT directory does not exist on the
destination (a deeper --files-from missing entry, -R or full-mirror layout) was
treated as a hard failure because file_open_secure_parent returned -1 when the
parent was missing. That aborted the whole run, skipped the --delete extras
walk, and tore down an early --delete-before/during connection, contradicting
'missing mirror = no-op / all-missing succeeds'. A parent-open failure is now a
no-op when errno is ENOENT/ENOTDIR (matching file_remove_tree_secure); only a
genuine I/O error fails the run.
Also: an already-absent mirror reached via unlinkat-ENOENT no longer prints
'Deleted: <path>' (a no-op dressed as a deletion); the per-path 'Deleted:' line
is printed only when an entry was actually removed.
Adds real algorithm selection (xxh64 default, plus md5 via OpenSSL EVP) and a
64-bit seed for the per-file whole-file digest used by the --incremental/
--checksum handshake and basis-dir content verification. The seed also feeds
the delta path's per-block xxHash32 strong checksum (low 32 bits) so an
explicit seed deterministically changes those digests too. Sender and receiver
hash identically: the algorithm id and seed cross the config wire frame and the
STATUS_CHECK handshake now carries a length-prefixed, bounded digest instead of
a fixed 64-bit value. Unsupported algorithm names are rejected at parse time
(never a silent no-op). PROTOCOL_VERSION bumped 2.9.0 -> 2.10.0; defaults
(xxh64, seed 0) preserve prior byte-for-byte behavior.
Implement rsync's append modes: when an existing destination file is SHORTER
than the source, the receiver negotiates a resume offset and only the tail is
transferred; the full file (retained prefix + tail) is rebuilt and installed
through the normal atomic store path, so the result is byte-identical to the
source whenever the prefix matches.
- --append: sends the tail without content-verifying the retained prefix
(rsync parity; the documented prefix-trust risk).
- --append-verify: verifies the retained prefix against the source's prefix
xxHash64 before appending and, on a mismatch, falls back to a clean full
transfer (never a corrupt prefix+tail blend).
New wire frames STATUS_APPEND / STATUS_APPEND_SIG / STATUS_APPEND_OK /
STATUS_APPEND_DATA; PROTOCOL_VERSION bumped 2.9.0 -> 2.10.0 (peers must match).
Both flags imply --incremental and are incompatible with -s (chunk
serialization) and --whole-file (rejected up front). Respects --inplace,
--partial/--partial-dir and --delay-updates via the shared store engine.
PROTOCOL_VERSION 2.9.0 -> 2.10.0. The STATUS_MANIFEST frame gains a third
section carrying destination-relative exact-delete paths (the missing
--files-from entries' mirrors); the config frame gains a delete_missing_args
bool (ignore_missing_args stays client-only). The receiver validates the third
section like the keep-set and commits it with manifest_delete_all():
manifest_delete_missing_args runs first (explicit user requests, never blocked
by protected-prefix exclusion protection; staging/basis protected; a non-empty
directory mirror removed only under --force/--delete, rsync parity) and then the
ordinary extras walk. Server --allow-delete gates it like --delete.
The suffix-trim loop using computed end offsets tripped cppcheck's
knownConditionTrueFalse value-range analysis (it unsoundly concluded the trims
always consume the whole middle). Rewrite it with explicit moving end indices
and add an inline suppression with a rationale for the residual false
positive; cppcheck --error-exitcode=1 is clean again. The trimming logic is
unchanged and was verified against a full DP reference over 200k random name
pairs.
Review follow-ups on the --fuzzy candidate scan:
- Allocate the two DP rows once per directory scan instead of once per
candidate (4096-entry directories no longer do thousands of malloc pairs).
- Pre-prune before the DP with two cheap lower bounds on the edit distance:
the name length gap and the count of characters of one basename absent from
the other; a candidate whose gate (distance*2 <= longer) already fails on
the max of those bounds is skipped without running the DP.
- Trim the common prefix and non-overlapping common suffix before the DP so
it only runs over the differing middles.
- Note that the 4096 readdir cap bounds iterations, not per-entry DP cost,
and that the seen set is filesystem-order dependent (winner stays
deterministic via the total comparator).
- Open the chosen candidate with O_NONBLOCK so a name raced to a FIFO cannot
block the receive thread forever in open(2); the existing fstat S_ISREG gate
still rejects non-regular files. (The pre-existing basis_open_regular has
the same latent FIFO pattern and is intentionally left unchanged.)
- Free old_data in receive_delta_file's defensive NULL guard.
The STATUS_MANIFEST frame now carries two count-delimited sections: the kept
paths and a protected-prefix list (excluded-on-source paths the walker must not
delete unless --delete-excluded opted out). The receiver's DeleteManifest is
passed through the commit/early paths unchanged. manifest_delete_extras
honors a client --max-delete (all-or-nothing) and produces a distinct error for
it versus the 100000-entry server bound. --force clears a non-empty directory
that blocks an incoming regular file (confined, symlink-safe) via a new
file_remove_tree_secure helper.
When a file must be transferred and the destination holds no usable content
at the exact path (file absent, or outside the delta engine's size bounds),
the receiver now searches the target's own destination directory for an
existing regular file with a similar basename and uses it as the delta basis
via the existing receiver-driven STATUS_DELTA_SIGNATURE handshake. The
sender never learns the basis was another file, so no wire change beyond the
new config flag was required.
Heuristic (deterministic, simpler than rsync's, documented): candidates are
sibling entries confined below the root and opened O_NOFOLLOW (symlinks are
never followed, nothing outside the destination root is read); dotfiles,
directories, the target's own name and stage/temp names are excluded; size
gate is delta_should_attempt; name gate is a Levenshtein distance <= half
the longer basename; the closest candidate (size tie-break, then lexical) is
loaded; the scan is capped at 4096 entries.
Byte-exactness is independent of the basis: block matches are verified by
Adler-32 + xxHash32, delta_apply validates every reference, and a basis that
shares nothing makes the sender reply with a whole-file transfer. When no
candidate qualifies the normal whole-file transfer runs unchanged.
- copy-dest basis hits leaked the heap-allocated basis path: BASIS_DEST_COPY
did not transfer it (only LINK does) and returned before the basis cleanup.
basis_match_free is now called on every materialization return path (success
and send-failure) after content/link ownership is transferred.
- the --delete walker regression: the delay-updates staging name must be
protected only as a DIRECT child of the receive root, while basis dirs may
be skipped at any depth. delete_extras_limited now takes DeleteSkipEntry
entries carrying a top_level_only flag instead of a flat prefix list, so a
nested destination directory named .fastsync-stage is ordinary content again
(its extras are deleted) and a basis tree is still never removed.
Deletion timing is now real and selected by the four rsync flags plus the
plain --delete default. Wire protocol bumps to 2.8.0: two new config
booleans (delete_during, delete_delay) are serialized and validated, joining
the existing delete_before/delete_after.
- Early modes (--delete-before, --delete-during/--del): the sender pre-scans
the whole tree (paths only), transmits the keep-set manifest BEFORE any
file data, and the receiver removes extras and acks STATUS_OK; the sender
only streams data after the deletion committed. Deletion is thus performed
even if a later transfer phase fails (rsync delete-before/during are
destructive by definition). FastSync streams in a single scan so it cannot
interleave per-directory like rsync delete-during; --delete-during selects
the same engine mode as --delete-before (documented divergence).
- Late/commit modes (plain --delete, --delete-after, --delete-delay): the
manifest closes the data stream and deletion is committed only after
STATUS_FINISHED proves the whole transfer succeeded, preserving FastSync's
commit-style safety. --delete-delay converges with --delete-after because
FastSync never snapshots the destination during data flow (documented).
- The STATUS_MANIFEST frame is now self-delimiting and position-independent.
Single-threaded receivers delete before the success frame; the -m receiver
hands the keep-set to server.c, which commits the deletion only after the
disk writer thread has drained (fixes a delete-vs-in-flight-temp race).
- Every timing flag implies --delete; at most one timing flag is allowed.
- Each timing flag implies --delete, matching rsync; conflicts are rejected.
The receiver's per-file incremental check now consults the ordered basis-dir
list whenever the destination is not already up to date. An exact basis match
requires equal size, equal mtime (unless --size-only; --ignore-times disables
basis matching like rsync), and an equal content xxHash64 -- the sender sends
its xxHash for every file whenever basis dirs are configured (not only under
--checksum), so a hard link or local copy is only ever made from byte-identical
content.
On a match:
- compare-dest: reply STATUS_OK and skip data only when the destination does
not already hold the file (sparse, rsync parity). A destination that holds
a DIFFERENT version falls back to a normal transfer instead of rsync's
delete, keeping the mirror complete.
- copy-dest: reply STATUS_OK and hand a synthetic File (bytes read from the
basis file, basis metadata) to the normal store sink, so the file is
installed as a real local copy through the existing atomic temp+rename
engine and honors --existing/--ignore-existing/--update/--backup/
--delay-updates/--partial-dir unchanged.
- link-dest: same, but File.basis_link records the basis path and the store
engine calls the new file_to_disk_secure_link(): an atomic temp hard link +
rename. Cross-filesystem/refused links fall back to a byte-identical local
copy (never a corrupt or partial file); the copy fallback applies metadata,
while a successful link keeps the basis inode's own attributes so the basis
file is never mutated.
Basis-materialized files carry File.skip so they are not acknowledged to a
--remove-source-files sender (the sender already saw STATUS_OK and keeps the
source). The no-match path is byte-for-byte identical to the existing delta /
full-data transfer.
RSYNC_COMPAT Phase-2 row M: path-list construction and destination
directory creation while preserving traversal safety.
- -R/--relative with --files-from: transmit each listed entry under its
bare relative destination path (no source-root mirror). Files keep an
absolute local read path plus a separate wire/dest path (File.send_path);
manifest, incremental quick-check and change output follow the wire path,
so --delete and --remove-source-files stay consistent. -R without
--files-from is unchanged (full mirror).
- --no-implied-dirs: client-only, only meaningful with -R + --files-from.
A listed file whose parent dir is not itself (or via an ancestor)
explicitly listed cannot be placed; the run fails up front with a clear
error. No effect otherwise.
- --dirs/-d + --old-dirs/--old-d aliases: -d <dir> transmits the source
root as an explicit empty directory entry (STATUS_MKDIR frame); with
--files-from listed dirs are created empty and listed files transferred,
never descending. Works single-threaded, -m (sequential scanner in the
-m scan thread) and chunk-serialization (per-file type marker).
Directory entries appear in the delete manifest.
- --mkpath: new wire bool; server creates the destination root (and missing
leading components under its authorized root) at connection start. A
missing destination root is now rejected by default.
- Protocol bumped to 2.7.0 (mkpath wire field + STATUS_MKDIR + chunk type
marker). All receive paths funnel through file_save_to_disk_full which
creates directories via the secure confined mkdir engine; dir entries are
excluded from --remove-source-files outcome acknowledgements on both ends.
- Unit coverage: CLI parse (relative/dirs aliases/mkpath/no-implied-dirs),
config round-trip (relative + mkpath), scanner --dirs non-recursion and
-R send_path (sequential + parallel), receiver dir-entry save.
- Integration coverage: TestRelativeFilesFrom, TestNoImpliedDirs, TestDirs,
TestMkpath (single and -m).
- RSYNC_COMPAT: 4 rows move to Implemented (Summary 67/3/5/1/71 = 147).
Review fixes for --delay-updates:
- --delete no longer deletes the staged files: the delete walker gains a
skip_root_child parameter and receive_manifest passes DELAY_UPDATES_STAGING_DIR
when delay_updates is active, so deletion removes genuine extras while the
staging dir (a direct child of the receive root) is left for publication in
both single and -m modes.
- --backup-dir is rejected when it collides with the reserved internal staging
name .fastsync-stage (trailing slash normalized), in client validation and in
the received-config wire validation, preventing old backups from being
silently installed as new files.
- Staging dir is now held under an exclusive advisory flock for the whole
transfer (context lifetime): two simultaneous delayed transfers to one
destination root no longer share/destroy each other's staged data - the
second fails cleanly. Cleanup only touches the staging dir when this context
owns the lock, so a lock-contention failure cannot wipe a live session.
- Post-publish staging cleanup now returns/logs instead of discarding failures
(warning when the staging dir cannot be fully removed).
- Reworked the publish-failure integration test to exercise real mid-publish
semantics (top-level file published, nested rename fails, no rollback,
sources retained under --remove-source-files) and added integration tests for
--delete + --delay-updates ordering and reserved --backup-dir rejection.
- RSYNC_COMPAT note documents delete ordering, the reserved-name hazard, and
the concurrency guard.
Stage every successfully written file under a private 0700 .fastsync-stage
directory inside the receive root and atomically publish all staged files
only after the whole protocol stream (manifest/delete handling included)
has completed, immediately before the success/outcome frame. On any
abort/error before publication nothing is installed and staging is removed;
a publish failure aborts the transfer with best-effort cleanup of the
remainder (already-published files are not rolled back). Crash leftovers
are wiped when the next delayed transfer starts.
Wire: new delay_updates config flag (selection-options block), protocol
version bumped to 2.6.0, client/server validation rejects --inplace.
CLI/usage/validation updated. Works in single-threaded and -m modes
(exactly one write_thread stages files; the staged-file registry is
mutex-protected; publication runs once after both threads join).
--existing/--ignore-existing/--update decide against the final destination
at stage time; --backup is deferred to publication. remove_source_files
outcomes are only sent after publication so skipped/unpublished sources are
never deleted. Default (no flag) behavior is unchanged.
Tests: config wire round-trip, CLI parse, --inplace rejection, new
test_delay_updates unit suite (27 suites total), and integration
TestDelayUpdates covering single/-m parity, incremental reruns, remove
source files, receiver-skip ordering, and a deterministic publish-failure
abort path.
Review nits from independent review of the four fix branches:
- receive_delta_file STATUS_NEXT oversize branch now sets *failed=true
- receive_incremental_check oversize branch returns NULL (receiver sends the
single STATUS_ERROR) instead of double-sending
- add multithreaded -m --ignore-existing --remove-source-files integration
coverage so the writer-thread outcome path is exercised
#251 --remove-source-files deletes sources that were skipped receiver-side
(--existing/--ignore-existing/--update). The receiver now reports a
per-file outcome for every processed data file when the sender requests
removal; the client only unlinks sources the receiver actually wrote.
add remove_source_files to the wire config and bump the protocol to 2.5.0.
#252 --backup/--suffix/--backup-dir broken by NULL-vs-empty wire loss. Receivers
canonicalize the empty wire string back to NULL for backup_dir, temp_dir,
partial_dir and suffix, and --suffix is received unconditionally.
#253 --partial --partial-dir never installed completed files. file_save_to_disk
now renames a fully written partial-dir file into the real destination.
#255 STATUS_CHECK read the entire old file before the size/mtime quick check.
Old contents are only read when a checksum compare or delta needs them.
#256 receive_delta_file failure paths did not set *failed, so the caller sent
STATUS_NEXT and waited for a body that never came. Every NULL return now
marks the transfer failed.
#257 files >64 MiB could not transfer. Whole-file receive caps raised to the
256 MiB connection/allocation ceiling (chunk caps stay 64 MiB) and the
client ignores SIGPIPE so a server-side close surfaces as a clean error.
Unit tests added: config NULL-vs-empty round trip, incremental quick-check
skip/NEXT paths, delta oversize failure, partial-dir install, save-result
skip reporting.
The Phase 1 merge conflict resolutions introduced formatting that failed
the CI lint job (clang-format 18.1.3). Reformatted with the exact CI
version; no functional changes.
- file.c split layout retained; security-hardened secure-fs helpers
(open_secure_parent/to_disk_secure/rename_secure/stat_secure) now live in
file.c with file_ prefix and are shared with file_receive.c
- file_receive.c takes the security branch's bounded allocations
(receive_data_limited, data_decompress_limited, size checks) and
STATUS_ERROR signaling
- file_send.c gains the data consistency check on file->data
- client_validation.c: stricter --tls requiring --ca, log_message style
- utils.c: hardened openat/mkdirat mkdir_r from security branch
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