The MOTD used to ride on tui_render_command_output's coattails — text
got stuffed into client->command_output prefixed by "=== 公告 / MOTD ==="
and rendered under a reverse-video " COMMAND OUTPUT " title bar. Two
different things (a transient command result vs. a one-shot service
notice) wearing the same chrome.
Now MOTD has its own renderer with its own aesthetic:
╭─ 公告 / MOTD ────────────────────────────────╮
欢迎来到 TNT 公共聊天室。
请互相尊重，不要刷屏。
管理员：m1ng
╰─ 按任意键继续 / press any key ────────────────╯
- title chip embedded in the top border (bright cyan)
- footer hint embedded in the bottom border (dim grey)
- 2-column left padding on body lines, blank top/bottom pad rows
- dim cyan borders, no full-line reverse anywhere
Wiring:
- new tui_render_motd() declared in tui.h
- new client_t.show_motd flag selects the renderer; command_output
remains the text storage (no extra buffer needed)
- input.c MOTD path sets show_motd = true and calls tui_render_motd()
- handle_key's dismiss path clears show_motd alongside command_output
- main-loop redraw dispatch checks show_motd before command_output[0]
When the rendered message snapshot crosses a date boundary, insert a
single dim grey divider line before the first message of each new day:
── 2026-05-14 ──────────────────────────────────────────
16:00 alice: 早！
16:01 bob: 早呀
── 2026-05-15 ──────────────────────────────────────────
04:30 alice: 晚上一起吃饭？
...
The divider also fires for the *first* visible date, so the user always
knows what day the top of their viewport belongs to.
Dividers and messages share the fixed msg_height budget — dividers
don't push other content off the bottom. In the worst case a viewport
with one message per day shows half the rows as dividers, which is the
intended trade for readability.
Real win for a long-lived public chat where messages span many days
and timestamps alone only show HH:MM.
NORMAL mode status line:
before: "-- NORMAL -- (3/100) ↓ 5 new"
after : "[reverse-yellow NORMAL] 3 / 100 ▼ 5 new"
- the mode is now a small reverse-video yellow chip so it visually
echoes the mode colour in the title bar
- position is dim grey with em-spaced slash, "▼" replaces "↓" so the
unseen-message marker matches the same downward-triangle vocabulary
the help screen uses
INSERT mode prompt:
before: "> "
after : "› " (U+203A, dim grey)
- single-glyph chevron is quieter than the ASCII ">", aligns with the
thinner aesthetic of the new title bar
- applied both in tui_render_screen() and tui_render_input() so
per-keystroke redraws match the initial paint
COMMAND mode prompt:
before: ":foo"
after : "[magenta :]foo"
- the leading colon picks up the COMMAND mode colour so it reads as
"you are in command mode now" rather than as part of the typed text
Replace the full-width reverse-video title
▍ tester | 在线: 3 | 模式: INSERT | ? 帮助 ▎ (reversed)
with a single line of small chips on a normal background:
tester · 在线 3 · INSERT ? 帮助
- username is bold white, online count is plain
- mode name carries its own colour, so glance + colour disambiguates
it (INSERT cyan, NORMAL yellow, COMMAND magenta, HELP blue) without
having to read the word
- separators are dim grey middle-dots so the eye groups segments
- mute marker shrinks from "[静音]" to a dim "静音" suffix when active
- hint "? 帮助" is right-aligned in dim grey, far from content
The horizontal rule below the chat already provides the visual divider
that the reverse-video bar used to provide, so the bar can drop the
heaviness without losing structure.
Replace the four lines of `==` rules + bilingual title with a centred
rounded box so the eye lands on a single visual element instead of two.
The new tui_render_welcome():
- centres horizontally and vertically (about a third of the way down)
- shows TNT + version, then 中文 subtitle, then English caption with
decreasing visual weight (bold cyan / default / dim grey)
- falls back to a plain "TNT $version — anonymous chat over SSH" line
when the terminal is too narrow for the frame
- declared in tui.h, called from input.c read_username()
read_username()'s prompt becomes a single short bilingual hint
("请输入用户名 (留空 anonymous): ") that lives below the box.
Move client_t I/O and lifecycle out of ssh_server.c into a dedicated
module. ssh_server.c is now down to the listening socket, host key
setup, ssh_server_init / ssh_server_start, and the accept loop.
Migrated to client.{c,h}:
- client_send, client_printf
- client_addref, client_release (and the ssh_session / ssh_channel /
channel_cb teardown that fires on the final release)
- client_install_channel_callbacks
- client_channel_window_change / _eof / _close (the post-bootstrap
callbacks that target the client_t)
The client_t struct definition stays in ssh_server.h so we don't have
to revisit every existing #include chain. bootstrap, commands, exec,
input, and tui pick up the new client.h alongside their existing
ssh_server.h include.
ssh_server.c shrinks from 402 to 249 lines (-153).
Final per-module size after PR2:
ssh_server.c 249 accept loop + ssh_server_init/start + host key
bootstrap.c 493 per-connection SSH handshake / auth / channel
client.c 162 client_t I/O + lifecycle + channel callbacks
input.c 637 username read + handle_key + main loop +
notify_mentions + idle timeout
commands.c 269 vim ':' command dispatcher
exec.c 453 SSH exec subcommand dispatcher
ratelimit.c 197 IP rate limit + connection counters
tui.c 614 screen rendering
chat_room.c 151 room + client list
message.c 350 message log load/save/search
utf8.c 250 UTF-8 width / validation
common.c 133 buffer_*, env_int, is_valid_username,
sanitize_terminal_size, tnt_state_*
main.c 109 process entry
Total: ~4 000 lines of C across 13 files, no file over 650 lines, every
file is single-purpose. Behaviour is preserved: the migrated code is
byte-for-byte identical.
Move the interactive session — username read, vim-style key dispatcher,
main poll/redraw/keepalive/idle-timeout loop, the @mention bell, and
the tear-down path — out of ssh_server.c into a dedicated module.
New API (include/input.h):
- input_init() -- read TNT_IDLE_TIMEOUT once at startup
- input_run_session(client_t*) -- run the interactive session for an
already-bootstrapped client_t,
including exec_dispatch() short-circuit
when client->exec_command is set
- notify_mentions(content, sender) -- moved from ssh_server.h since
the INSERT-mode send path lives here
too
Renamed: client_handle_session(void *arg) -> input_run_session(client_t *).
The old void* signature was a fossil from when this was a pthread entry;
bootstrap.c calls it synchronously inside its own detached thread.
bootstrap_run() now ends with `input_run_session(client); return NULL;`.
g_idle_timeout is now private to input.c; ssh_server_init() calls
input_init() instead of reading the env directly.
ssh_server.c shrinks from 1026 to 402 lines (-624) -- now down to just
the accept loop, ssh_server_init / ssh_server_start, host-key setup,
client_t I/O API (send/printf/addref/release), and the post-bootstrap
client_channel_* callbacks. M6 will give those a proper home.
Behaviour is preserved: all moved code is byte-for-byte identical.
Move the per-connection SSH bootstrap pipeline -- key exchange, auth,
channel open + PTY/shell-or-exec request, and the hand-off into a
client_t -- out of ssh_server.c into a dedicated module.
Migrated to bootstrap.{c,h}:
- session_context_t (now private to bootstrap.c)
- accepted_session_t (declared in bootstrap.h, the IPC envelope from
the accept loop into the bootstrap thread)
- TNT_ACCESS_TOKEN handling: g_access_token + bootstrap_init()
- constant_time_strcmp (auth-only utility)
- bootstrap_peer_ip (peer IP read from libssh fd)
- auth_password / auth_none / auth_pubkey
- destroy_session_context, cleanup_failed_session
- channel_open_request_session, channel_pty_request,
channel_pty_window_change, channel_shell_request, channel_exec_request
- setup_session_channel_callbacks
- bootstrap_run (formerly bootstrap_client_session, the pthread entry)
Stayed in ssh_server.c:
- accept loop in ssh_server_start (now calls bootstrap_peer_ip and
pthread_create(bootstrap_run))
- ssh_server_init (now calls ratelimit_init() + bootstrap_init() +
reads only g_idle_timeout / TNT_BIND_ADDR / TNT_SSH_LOG_LEVEL)
- client_send/printf/addref/release, notify_mentions
- client_channel_window_change/eof/close (post-bootstrap, target client_t)
- client_install_channel_callbacks (renamed from
install_client_channel_callbacks, now non-static and exposed via
ssh_server.h so bootstrap.c can install them on the new client_t)
- read_username, handle_key, client_handle_session (will move to
input.c in PR2-M5)
- setup_host_key, ssh_server_start_time
Two helpers also lifted: sanitize_terminal_size moved to common.c (used
by the bootstrap PTY callback and the post-bootstrap window-change
callback), and is_valid_username already lived there from M2.
ssh_server.c shrinks from 1513 to 1026 lines (-487).
Behaviour is preserved: implementations are byte-for-byte the same.
Move the vim-mode `:` command dispatcher (`:list`, `:nick`, `:msg`,
`:last`, `:search`, `:mute-joins`, `:help`, `:clear`, `:q`, …) out of
ssh_server.c into a dedicated module.
New API (include/commands.h):
- commands_dispatch(client_t *) -- single entry point invoked from
handle_key when Enter is pressed in MODE_COMMAND.
ssh_server.c shrinks from 1769 to 1513 lines (-256).
Behaviour preserved: implementation is byte-for-byte the same.
Move the SSH exec subcommand interface (help, health, users, stats,
tail, post) and the dispatcher out of ssh_server.c into a dedicated
module.
New API (include/exec.h):
- exec_dispatch(client_t *) -- single entry point invoked from the
bootstrap path when client->exec_command[0] != '\0'.
Helpers that travel with the exec subcommands:
- format_timestamp_utc, trim_ascii_whitespace, json_append_string,
resolve_exec_username, parse_tail_count
Two cross-module bridges:
- is_valid_username() lifted into common.c/h since exec, the input
read path, and the :nick command all need it.
- ssh_server_start_time() added to ssh_server.h as a read-only
accessor; exec_command_stats no longer reaches into the global.
- notify_mentions stays in ssh_server.c for now and is exposed via
ssh_server.h. Will move to a dedicated client.c during PR2-M6.
ssh_server.c shrinks from 2200 to 1769 lines (-431).
Behaviour is preserved: implementations are byte-for-byte the same.
Move IP rate-limiting, auth-failure tracking, and global connection
counting out of ssh_server.c into a dedicated module.
New API (include/ratelimit.h):
- ratelimit_init()
- ratelimit_check_ip() / ratelimit_release_ip()
- ratelimit_record_auth_failure()
- ratelimit_check_and_increment_total() / ratelimit_decrement_total()
- ratelimit_get_active_total() (replaces the direct g_total_connections
read that exec_command_stats was doing under g_conn_count_lock)
env_int() also moves up to common.{c,h} since multiple modules need it.
ssh_server.c drops from 2469 to 2200 lines. Behaviour is preserved:
the new functions are byte-for-byte the same implementations, only the
file boundary moved.
g_idle_timeout and g_access_token reads stay inline in ssh_server_init()
for now; they will follow the auth.c and input.c extractions later.
Fixes:
- message_load() now holds g_message_file_lock for the read, so :last [N]
can no longer observe a half-written line while message_save() is
flushing.
- constant_time_strcmp() accumulates the length difference in size_t.
The old code truncated to unsigned char, which collapsed pairs whose
lengths differed by a multiple of 256 down to 0 and lost the signal.
Refactor:
- buffer_appendf() / buffer_append_bytes() moved to common.c; the two
identical copies in ssh_server.c and tui.c have been removed.
Docs / cleanup:
- README clarifies that exec 'post' uses the SSH login name as the
author and that anonymous mode performs no identity check.
- Removed TODO.md (both items completed) and docs/README.old.
- Trimmed the auto-generated 2025 entry block from docs/CHANGELOG.md
and added a 2026-05-16 entry summarising this change.
- :last [N]: show last N messages from log (max 50, default 10)
- :search <keyword>: case-insensitive full-text search across log history
- :mute-joins: per-client toggle to silence join/leave system messages,
indicated by [静音] in the title bar
- MOTD: display motd.txt from state directory on connect before entering chat
- Add message_search() to message.c/h for log file scanning
- Update :help and tui help screen (EN/ZH) with new commands
- @mention: typing @username in a message sends bell char to that user
and highlights the message content in bold yellow for them
- Idle timeout: disconnect inactive clients after TNT_IDLE_TIMEOUT
seconds (default 1800 = 30min, 0 to disable)
- :list now shows connection duration per user (e.g. "alice (12m)")
- Document all three features in help text, manpage, and README
Closes#46
- Color-code usernames using hash-based ANSI color assignment (6 colors)
- Style system messages (join/leave/rename) in gray with --> prefix
- Style /me action messages in italic cyan
- Show "↓ N new" indicator in yellow when scrolled up in NORMAL mode
- Compact timestamps from full date to HH:MM for more message space
Closes#44
- Add /me action command to all help surfaces (EN/ZH help screen,
:help output, exec help, manpage, README)
- Add Ctrl+D/U/F/B page scrolling keys to help text (were only in manpage)
- Add :q/:quit/:exit disconnect command to help text
- Update README COMMAND mode section with all current commands
(:nick, :msg, :w were missing)
- Remove redundant COMMAND MODE KEYS section from help text
(merged into AVAILABLE COMMANDS for clarity)
- Compact help screen layout (j/k on one line, g/G on one line)
- Replace all direct client->width/height reads with local variables
clamped to minimums (width>=10, height>=4) across tui_render_screen,
tui_render_input, tui_render_command_output, and tui_render_help
- Fix tui_render_input underflow when width < 3 (avail = max(rw-3, 1))
- Show username in title bar instead of generic label
- Add /me action message support in exec_command_post for scripting parity
- Reject empty usernames when loading messages from log file
- :nick/:name <name>: change username in-session with full validation,
thread-safe update under write lock, and system broadcast
- /me <action>: IRC-style action messages displayed as "* user action"
- Updated help text (EN/ZH) and manpage with new commands
Closes#38
- Whisper: copy target client ref out of room lock before calling
client_send, preventing lock-ordering inversion deadlock
- Channel callbacks: call ssh_remove_channel_callbacks before releasing
refs to prevent use-after-free if a callback fires during cleanup
- Log rotation: rotate messages.log to messages.log.1 when it exceeds
10 MiB, preventing unbounded growth on public servers
- tail -nN: accept both "tail -n5" and "tail -n 5" forms, matching
standard Unix tail behavior
Closes#36
- auth_pubkey: return SSH_AUTH_SUCCESS for key offers instead of
SSH_AUTH_PARTIAL, which incorrectly signals partial authentication
- command history: replace strncpy with snprintf to eliminate
-Wstringop-truncation warning on GCC
- utf8_is_valid_sequence: reject NUL byte (0x00) in single-byte
validation to prevent C string truncation attacks
Closes#34
Bug fixes:
- Fix data race on client->width/height (now _Atomic int)
- Persist join/leave system messages via message_save()
- Make room_add_message static to enforce lock contract
- Fix execute_command mutating command_input directly
- Increase help_copy buffer from 4096 to 8192 for CJK safety
New features:
- Add :msg/:w whisper command for private messaging
- Add command history with UP/DOWN arrows in command mode
- Add Ctrl+D/U/F/B page scrolling in normal mode
- Add :q/:quit/:exit Vim-style disconnect
Unix community:
- Add tnt.1 manpage (roff format) with full documentation
- Add manpage install/uninstall to Makefile
- Fix backspace in read_username to erase correct display width for
CJK/wide characters (was erasing only 1 column for 2-column chars)
- Add UTF-8 multi-byte input support in COMMAND mode (was silently
dropping non-ASCII bytes, breaking CJK command arguments)
- Reduce SSH auth timeout from 30s to 10s to limit connection-slot
exhaustion from slow/malicious handshakes
- Add 11 unit tests for chat_room.c covering: create/destroy, message
add/overflow, broadcast sequence, get_message bounds, client
add/remove/capacity, and null argument handling
- Add unit-test target to root Makefile so `make test` runs unit tests
before integration tests
- Add common.c to unit test link dependencies (needed for tnt_state_path)
- Guard _DARWIN_C_SOURCE define to prevent -Wmacro-redefined warning
- Check ftell() return for errors (-1) in message_load to prevent
corrupted backward scan on I/O failures
- Cap ssh_channel_write chunks to 32KB to prevent size_t-to-uint32_t
narrowing on large buffers
- Log evicted active connection count in rate-limit table overflow
warning for better diagnostics
- Fix use-after-free/double-free on install_client_channel_callbacks
failure: nullify session/channel ownership before releasing refs so
cleanup_failed_session does not double-free resources
- Fix constant_time_strcmp to always iterate over the full secret length,
preventing timing leak of token length
- Fix data race on client->width/height by protecting window-change
callback writes with io_lock
- Fix potential UTF-8 mid-sequence truncation in tui_render_input by
sizing display buffer to MAX_MESSAGE_LEN
Critical fixes:
- C-1: Use atomic_bool for client->connected and redraw_pending to prevent
data races between callback and main threads
- C-2: Add reference counting for channel callbacks to prevent use-after-free
when callbacks fire during client cleanup
- C-3/M-7: Use ssh_channel_read_timeout (5s) for UTF-8 continuation bytes
to prevent thread blocking and stream desynchronization
High-severity fixes:
- H-1: Replace non-thread-safe setenv/tzset with timegm() in parse_rfc3339_utc
- H-2: Change room_get_message to return by value copy instead of interior pointer
- H-3: Log warning when rate-limit table evicts active IP entry
- H-4: Replace strcmp with constant-time comparison for access token validation
- H-5: Check signature_state in auth_pubkey to reject unsigned key offers
Medium/low fixes:
- M-1: Replace all atoi() with strtol() for proper error detection
- M-3: Move calloc outside rwlock in tui_render_screen to avoid blocking writers
- M-8: Fix off-by-one in rate limit threshold (> to >=)
- M-9: Trim partial UTF-8 sequences after snprintf truncation in message_format
- L-1: Validate continuation byte mask (0xC0==0x80) in utf8_decode
- D-3: Remove vestigial client_t.fd field
- L-3: Remove unreachable pthread_attr_destroy after infinite loop
