A flat-file alternative to the SQLite chatlog backend with runtime
switching, full migration tooling, integrity verification, and a
synthetic load harness. SQLite remains the default; both backends share
one dispatch layer (db_backend_t vtable) so callers don't change.
Storage layout
- Per-contact append-only `flatlog/<account>/<contact>/history.log`
under XDG_DATA_HOME, one line per message
- Single-line file header with embedded format-version marker
(FLATFILE_FORMAT_VERSION); reader warns on missing or mismatched
marker, writer and checker stay in sync via preprocessor
stringification
- Deterministic key=value metadata (`id`, `aid`, `corrects`, `to`,
`to_res`, `read`) plus escaped body \u2014 `\|`, `\]`, `\\`, `\n`, `\r`
literals prevent log injection
- Sparse byte-offset index (FF_INDEX_STEP=500) per contact for
O(log n) time-range lookups; rebuilt on inode / size / mtime
change, extended in-place when the file just grew
- Per-contact GHashTable caches for archive_id presence and
stanza_id \u2192 from_jid mapping (O(1) MAM dedup, O(1) LMC sender
validation)
Hardening
- Path-traversal protection: JID directory name normalisation
(`@` \u2192 `_at_`, slashes and `..` rejected at construction); every
per-contact path is anchored under the account's flatlog/
directory and validated before open
- Symlink-attack protection: every fopen / open uses O_NOFOLLOW; on
ELOOP the operation aborts with an error rather than following
- Filesystem permissions: log files created with mode 0600,
directories with mode 0700; both enforced at creation, verified
on each open and reported on drift by `/history verify`
- Atomic crash-safe export: write to a temp file via mkstemp (mode
0600, random suffix, no name collisions between concurrent
exports), fsync, then rename \u2014 partial state never replaces the
live file
- Concurrency: advisory flock(LOCK_EX) held for the duration of
every write, including append from live messages and full rewrite
from export, so two profanity processes can't interleave bytes
on the same log
- DoS / abuse guards:
* FF_MAX_LINE_LEN = 10 MB \u2014 lines longer than this are rejected
at read with a warning; the parser will not allocate
unbounded memory for a single record
* FF_MAX_LMC_DEPTH = 100 \u2014 `corrects:` chain walk stops at this
depth and emits a warning, preventing a malicious correction
cycle from spinning the apply pass
* FF_VERSION_SCAN_MAX = 16 \u2014 header version probe never reads
past 16 leading comment lines, even on garbage input
* Empty / inverted byte-range early-return in page-up read path
so a malformed time filter cannot cause an unbounded scan
* Zero-entry index guard so a file whose every line failed to
parse cannot cause a NULL deref on later page-up
- LMC sender validation: an incoming correction whose sender does
not match the original message's sender is rejected at write
time and surfaced via cons_show_error; a cycle in the apply pass
is broken via a visited-set
- jid_create_from_bare_and_resource treats NULL, empty string, and
the literal "(null)" as no resource and returns a bare jid;
similar normalisation for barejid eliminates the legacy
"user@host/(null)" artefact that leaked into stored fulljids
whenever g_strdup_printf("%s", NULL) ran inside create_fulljid
Commands
- `/history switch sqlite|flatfile` \u2014 runtime backend swap, closes
the old backend and opens the new one without reconnecting
- `/history export [<jid>]` \u2014 SQLite -> flat-file, merging with any
existing flatlog (dedup keyed on a SHA-256 hash mixing stanza_id,
timestamp, from_jid, body \u2014 robust against id reuse by older
clients)
- `/history import [<jid>]` \u2014 flat-file -> SQLite, same merge
semantics, runs inside a single SQLite transaction with rollback
on per-contact failure
- `/history verify [<jid>]` \u2014 integrity check; emits a structured
list of issues (ERROR / WARNING / INFO) per file:
* file-level: missing log, wrong permissions (\u2260 0600), UTF-8
BOM present, CRLF line endings, empty file
* line-level: invalid UTF-8 (with byte offset), embedded
control characters, unparsable lines, timestamps out of
order, duplicate `id:` and `aid:` (tracked separately so a
stanza/archive id collision isn't double-reported)
* cross-line: broken `corrects:` references whose target id is
not present in the file
- `/history backend` \u2014 show currently active backend
- Active backend indicator `[sqlite]` / `[flatfile]` in the status
bar next to the JID
- Roster-JID autocomplete for verify / export / import
- export and import open a SQLite handle on demand when the
flatfile backend is currently active, so migration works
regardless of which backend is live
Tests
- Unit: database_export (parser round-trip, escape/unescape, dedup
key stability, JID normalisation), database_stress (14 cases
exercising rapid writes, large messages, deep LMC chains, MAM
dedup, concurrent contacts)
- Functional: history persistence across reconnects, export /
import round-trip with content equality, MUC migration,
timestamp normalisation across timezones
- Bench harness P1\u2013P5 (synthetic load: bulk insert, time-range
read, page-up scroll, MAM ingest, mixed workload) and failure
modes F1\u2013F17 (page-up cursor and forward-iteration symmetry,
oversized lines, MAM dedup, LMC depth and cycles, BOM/CRLF,
missing log, empty file, mtime+inode flip, broken corrects, etc.)
- All bench tests integrate with the existing make targets and
emit CSV rows for baseline comparison
Author: jabber.developer2 <jabber.developer2@jabber.space>
Reviewed-by: jabber.developer <jabber.developer@jabber.space>
- Replace stbbr_for_id() with stbbr_for_query()/stbbr_send()
- Content-based stubbing matches stanzas by namespace instead of ID
- Use regex assertions for flexible output matching
- Fix timing issues in chat_session and presence tests
As 9f2abc75 accidentally got the ordering of some of the includes wrong,
I decided to propose my initial solution again.
Additional to that, I've opened a MR against CMocka to solve this on
their side, since I believe that the current way this is done is not
sustainable [0].
[0] https://gitlab.com/cmocka/cmocka/-/merge_requests/91
Fixes: 9f2abc75 ("Fix tests with gcc15 (uintptr_t)")
Signed-off-by: Steffen Jaeckel <s@jaeckel.eu>
CProof note: our new tests need to also be updated.
