Address confirmed receiver security findings B1-B6:
B1 (HIGH): add O_NONBLOCK to the three receiver read-opens that opened an
existing destination/basis entry before the S_ISREG gate
(incremental_check_open_destination, basis_open_regular, hardlink_read_source)
so a client-planted FIFO can no longer block the receive thread forever while
the post-open type gate still rejects it.
B2 (HIGH/MED): --inplace now fstatat(AT_SYMLINK_NOFOLLOW)-probes the target and
refuses any existing non-regular entry, opens with O_NONBLOCK, and re-checks
S_ISREG on the opened fd. This stops a FIFO from hanging the open and stops a
char/block device from being written directly (bypassing --write-devices).
B3 (MED): under --dry-run the incremental quick-skip no longer reads/hashes the
destination file for --checksum/--delta; it decides from metadata only and
reports would-transfer when the comparison is inconclusive, closing the
read-only-module content-hash oracle.
B4 (LOW): xattr_name_appliable() now gates the two system.posix_acl_* names on
preserve_acls (--acls), not the derived use_xattrs (--xattrs OR --acls). The
receiver drops (never applies) ACL entries when -A was not negotiated while
keeping user.* working for -X.
B5 (INFO): receive_manifest_section() charges a per-entry overhead against
MAX_MANIFEST_BYTES and the aggregate entry count across all three sections is
capped at MAX_MANIFEST_ENTRIES.
B6 (MED): data_charge_session() reserves decompressed/chunk-copy bytes against
the owning ProtocolSession (MAX_CONNECTION_MEMORY) and records them on the Data
so data_destroy() releases them via the Data.owner path. Applied to the
whole-file/append/delta decompression sites and chunk_deserialize() per-file
copies; a missing session owner degrades to the previous uncharged behavior.
Tests: FIFO destination/basis non-hang (with alarm), --inplace FIFO/device
refusal, dry-run no-read oracle test plus updated metadata-only dry-run tests,
ACL-without--acls drop, manifest total-entry cap, and chunk session charging.
- Reformat all C/H files to match .clang-format (LLVM style)
- Fix 26 cppcheck const-correctness warnings (constParameterPointer,
constVariablePointer, constVariable)
- Update function declarations in headers to match const parameters
- receive_chunk_data(fd, config) -> Chunk*: shared receive/decompress/deserialize
(eliminates ~25 lines of duplication between server.c and multiprocessing.c)
- receive_manifest(fd, config, next_status): moved from server.c to file.c,
fixes missing 'Deleting files not in manifest...' log in multiprocessing.c
- Removes redundant manual free loop in multiprocessing.c manifest handling
(array_list_create(free) destructor already handles this)
- server.c and multiprocessing.c: remove local chunk/manifest helpers,
remove compression.h include (no longer needed)
- Reduced test data from 50MB to 25MB (test.py)
- Increased SSH socketpair buffer to 1MB via setsockopt (transport_ssh.c)
- Made chunk size configurable: new Config field, --chunk-size CLI flag,
sent over wire, and used in scanner instead of DESIRED_CHUNK_SIZE
- Fixed DESIRED_CHUNK_SIZE macro parentheses (chunk.h)