feat(client): --port alias, --threads=N, graceful abort, keepalive

src/shared/config.c

@@ -23,6 +23,7 @@ static void config_set_defaults(Config* config) {
   config->receive_root_directory = NULL;
   config->save_to_disk = false;
   config->use_multithreading = false;
+  config->scanner_threads = 0;
   config->use_chunk_serialization = false;
   config->use_compression = false;
   config->use_metadata = false;
@@ -79,7 +80,6 @@ static void config_set_defaults(Config* config) {
   config->stats = false;
   config->max_depth = 0;
   config->log_file = NULL;
-  config->queue_size = 100;
   config->follow_symlinks = false;
   config->partial = false;
   config->copy_links = false;
@@ -147,14 +147,11 @@ static void config_set_defaults(Config* config) {
   config->delete_during = false;
   config->delete_delay = false;
   config->address = NULL;
-  config->bind_address = NULL;
   config->ipv6 = false;
   config->ipv4 = false;
   config->sockopts = NULL;
   config->sockopt_count = 0;
   config->daemon = false;
-  config->daemon_config = NULL;
-  config->server_mode = false;
   config->no_motd = false;
   config->checksum = false;
   config->checksum_algo = CHECKSUM_ALGO_XXH64;
@@ -789,9 +786,7 @@ void config_delete(Config* config) {
   free(config->partial_dir);
   free(config->suffix);
   free(config->address);
-  free(config->bind_address);
   free(config->sockopts);
-  free(config->daemon_config);
   free(config->compress_choice);
   free(config->chmod_spec);
   if (config->skip_compress_suffixes) {

src/shared/config.h

@@ -81,6 +81,11 @@ typedef struct Config {
   char* receive_root_directory;
   bool save_to_disk;
   bool use_multithreading;
+  /* -j/--threads=N: number of parallel scanner worker threads for the -m
+   * pipeline.  0 (the default, also set by bare -j/--threads) means "use the
+   * scanner's built-in default" (4).  CLIENT-ONLY: it is a local scheduling
+   * concern and is NEVER serialized into the wire config frame. */
+  int scanner_threads;
   bool use_chunk_serialization;
   bool use_compression;
   bool use_sendfile;
@@ -170,7 +175,6 @@ typedef struct Config {
   bool stats;
   int max_depth;
   FILE* log_file;
-  int queue_size;
   bool follow_symlinks;
   bool partial;
 
@@ -348,21 +352,17 @@ typedef struct Config {
 
   // PR #181: IPv6 and bind address
   char* address;
-  char* bind_address;
   bool ipv6;
   bool ipv4;
   /* --sockopts=OPTIONS (Phase 5, Wave B): strict allowlist of TCP/socket
    * options applied via setsockopt after socket() and before connect()/bind().
    * These are LOCAL socket concerns: they never cross the wire config frame.
-   * .address is the outgoing/source bind address (--address); .bind_address is
-   * reserved for daemon-side binding and is not wired yet. */
+   * .address is the outgoing/source bind address (--address). */
   SockOptEntry* sockopts;
   int sockopt_count;
 
   // PR #182: Daemon/server mode
   bool daemon;
-  char* daemon_config;
-  bool server_mode;
   /* --no-motd (Wave C): CLIENT-ONLY, never crosses the wire.  Suppresses
    * DISPLAY of the daemon's MOTD; the daemon still sends the MOTD frame, so
    * the client reads and discards it to keep the stream in sync.  rsync's

src/shared/protocol.c

@@ -609,6 +609,136 @@ bool protocol_receive_status_timed(ProtocolSession* session, Status* status, int
   return true;
 }
 
+/* Read exactly one Status frame within `deadline` (CLOCK_MONOTONIC).  Unlike
+ * protocol_receive_status_keepalive this never emits a keepalive: it is used
+ * to consume the first byte(s) of an already-signalled frame and to drain the
+ * peer's outstanding keepalive replies, where injecting a write could split a
+ * reply across a frame boundary.  Returns false on timeout/EOF/error. */
+static bool protocol_read_status_until(ProtocolSession* session, Status* status,
+                                       const struct timespec* deadline) {
+  Status received = STATUS_ERROR;
+  size_t got = 0;
+  while (got < sizeof(Status)) {
+    if (!session->ssl || SSL_pending(session->ssl) == 0) {
+      int remaining_ms = deadline_remaining_ms(deadline);
+      if (remaining_ms <= 0) {
+        log_message(LOG_LEVEL_ERROR, "Receive timeout while reading status");
+        return false;
+      }
+      struct pollfd pfd = {.fd = session->read_fd, .events = POLLIN};
+      int poll_result = poll(&pfd, 1, remaining_ms);
+      if (poll_result == 0) {
+        log_message(LOG_LEVEL_ERROR, "Receive timeout while reading status");
+        return false;
+      }
+      if (poll_result < 0) {
+        if (errno == EINTR)
+          continue;
+        return false;
+      }
+      if (pfd.revents & (POLLERR | POLLNVAL))
+        return false;
+    }
+    ssize_t bytes_received;
+    if (session->ssl)
+      bytes_received = SSL_read(session->ssl, (char*)&received + got, sizeof(Status) - got);
+    else
+      bytes_received = read(session->read_fd, (char*)&received + got, sizeof(Status) - got);
+    if (bytes_received <= 0) {
+      if (session->ssl) {
+        int ssl_err = SSL_get_error(session->ssl, (int)bytes_received);
+        if (ssl_err == SSL_ERROR_WANT_READ || ssl_err == SSL_ERROR_WANT_WRITE)
+          continue;
+      }
+      if (bytes_received < 0 && errno == EINTR)
+        continue;
+      log_message(LOG_LEVEL_ERROR, "Connection closed while receiving status");
+      return false;
+    }
+    got += (size_t)bytes_received;
+  }
+  *status = received;
+  return true;
+}
+
+bool protocol_receive_status_keepalive(ProtocolSession* session, Status* status, int timeout_sec,
+                                       int keepalive_interval_sec, ProtocolWaitAbort abort_check) {
+  if (!session || !status)
+    return false;
+  if (timeout_sec <= 0)
+    timeout_sec = RECEIVE_TIMEOUT_SEC;
+  if (keepalive_interval_sec <= 0)
+    keepalive_interval_sec = timeout_sec;
+
+  struct timespec deadline;
+  clock_gettime(CLOCK_MONOTONIC, &deadline);
+  deadline.tv_sec += timeout_sec;
+
+  unsigned long keepalives_sent = 0;
+  unsigned long replies_seen = 0;
+  Status final = STATUS_ERROR;
+  while (true) {
+    if (abort_check && abort_check())
+      return false;
+    if (!session->ssl || SSL_pending(session->ssl) == 0) {
+      int remaining_ms = deadline_remaining_ms(&deadline);
+      if (remaining_ms <= 0) {
+        log_message(LOG_LEVEL_ERROR, "Receive timeout after %ds", timeout_sec);
+        return false;
+      }
+      /* Only interleave a keepalive while waiting for the FIRST byte of a
+       * frame; once part of a frame is buffered a write could race the peer's
+       * reply into the middle of it. */
+      int interval_ms = keepalive_interval_sec * 1000;
+      int wait_ms = interval_ms < remaining_ms ? interval_ms : remaining_ms;
+      struct pollfd pfd = {.fd = session->read_fd, .events = POLLIN};
+      int poll_result = poll(&pfd, 1, wait_ms);
+      if (poll_result == 0) {
+        if (abort_check && abort_check())
+          return false;
+        if (!protocol_send_status(session, STATUS_KEEPALIVE))
+          return false;
+        keepalives_sent++;
+        continue;
+      }
+      if (poll_result < 0) {
+        if (errno == EINTR)
+          continue;
+        return false;
+      }
+      if (pfd.revents & (POLLERR | POLLNVAL))
+        return false;
+    }
+    Status received;
+    if (!protocol_read_status_until(session, &received, &deadline))
+      return false;
+    if (received == STATUS_KEEPALIVE) {
+      /* The receiver's answer to one of our keepalives. */
+      replies_seen++;
+      continue;
+    }
+    final = received;
+    break;
+  }
+  /* Drain the replies the receiver still owes for keepalives we sent while it
+   * was busy.  It answers them only after the real status, so leaving them
+   * unread would put stale KEEPALIVE frames ahead of the next exchange and
+   * desynchronize the protocol. */
+  while (replies_seen < keepalives_sent) {
+    Status drained;
+    if (!protocol_read_status_until(session, &drained, &deadline))
+      return false;
+    if (drained != STATUS_KEEPALIVE) {
+      log_message(LOG_LEVEL_ERROR, "Unexpected status while draining keepalive replies");
+      return false;
+    }
+    replies_seen++;
+  }
+  *status = final;
+  log_debug_message(LOG_DEBUG_PROTO, "Received Status: %s", status_to_string(*status));
+  return true;
+}
+
 bool send_str(int fd, const char* data) {
   return protocol_send_str(legacy_session(-1, fd), data);
 }
@@ -648,3 +778,8 @@ bool receive_status(int fd, Status* status) {
 bool receive_status_timed(int fd, Status* status, int timeout_sec) {
   return protocol_receive_status_timed(legacy_session(fd, -1), status, timeout_sec);
 }
+bool receive_status_keepalive(int fd, Status* status, int timeout_sec, int keepalive_interval_sec,
+                              ProtocolWaitAbort abort_check) {
+  return protocol_receive_status_keepalive(legacy_session(fd, -1), status, timeout_sec,
+                                           keepalive_interval_sec, abort_check);
+}

src/shared/protocol.h

@@ -198,4 +198,23 @@ bool receive_status(int file_descriptor, Status* status);
    this so the sender does not abort after the deletion already committed. */
 bool receive_status_timed(int file_descriptor, Status* status, int timeout_sec);
 
+/* Callback polled by protocol_receive_status_keepalive once per keepalive
+   interval.  Return true to stop waiting (e.g. a SIGINT/SIGTERM abort flag was
+   set).  Kept as a function pointer so the protocol layer does not depend on
+   client signal state. */
+typedef bool (*ProtocolWaitAbort)(void);
+
+/* Like receive_status_timed, but while the peer is silent it emits
+   STATUS_KEEPALIVE every keepalive_interval_sec (the receiver answers each with
+   STATUS_KEEPALIVE, which this function consumes and skips) so a long
+   server-side operation does not look like a dead connection.  The total wait
+   is still bounded by timeout_sec; abort_check (may be NULL) is polled every
+   interval and, when it returns true, ends the wait immediately with false.
+   Runs entirely on the calling thread: the protocol send path is NOT safe for
+   concurrent writers, so this must not be paired with a helper thread. */
+bool receive_status_keepalive(int file_descriptor, Status* status, int timeout_sec,
+                              int keepalive_interval_sec, ProtocolWaitAbort abort_check);
+bool protocol_receive_status_keepalive(ProtocolSession* session, Status* status, int timeout_sec,
+                                       int keepalive_interval_sec, ProtocolWaitAbort abort_check);
+
 #endif