refactor(delete): rename basis helper to delete_basis_relative

CMakeLists.txt

@@ -99,6 +99,7 @@ set(SHARED_SRCS
 	src/shared/daemon_limits.c
 	src/shared/data.c
 	src/shared/delay_updates.c
+	src/shared/delete.c
 	src/shared/delete_commit.c
 	src/shared/delete_plan.c
 	src/shared/delta.c

RSYNC_COMPAT.md

@@ -1013,7 +1013,12 @@ integration tests unless it is explicitly listed as a limitation.
 
 - **`--temp-dir` is confined to the receive root on the receiver:** a relative
   dir resolves below it; an absolute path or one containing `..` is rejected.
-  An `EXDEV` install falls back to a non-atomic copy instead of aborting.
+  An `EXDEV` install falls back to a non-atomic copy instead of aborting. (The
+  confined receiver path cannot be mount-tested in the CI container — no
+  `CAP_SYS_ADMIN` and unprivileged user namespaces are disabled — so the
+  cross-filesystem fallback is exercised end-to-end through the unconfined local
+  `--read-batch` apply against a `/dev/shm` scratch dir, in
+  `tests/integration/test_temp_dir_exdev.py`.)
 - **Deletion scoping:** the manifest carries the synchronized directories, so
   the extras walk only visits their subtrees; `--files-from` subsets no longer
   delete untransmitted paths outside the listed directories.

src/client/change_list.c

@@ -245,7 +245,7 @@ static char* change_render_name_uptodate(const ChangeEvent* event) {
  * resolves to xxh128, so an explicit selection and the default both render the
  * selected algorithm's digest. */
 static ChecksumAlgo out_format_checksum_algo(const Config* config) {
-  return (ChecksumAlgo)config->checksum_transfer_algo;
+  return (ChecksumAlgo)config->cli.checksum_transfer_algo;
 }
 
 /* Render a digest as rsync's sum_as_hex: xxh128 prints the HIGH 64-bit half

src/client/client_cli.c

@@ -170,7 +170,7 @@ static int set_positive_int_option(int* dest, const char* value, const char* opt
  * name is a hard error with rsync's exit code 4, never a silent no-op. */
 static int set_compression_choice(Config* config, const char* value) {
   if (!value) {
-    config->cli_exit_code = 4;
+    config->cli.cli_exit_code = 4;
     return -1;
   }
   int algo;
@@ -178,7 +178,7 @@ static int set_compression_choice(Config* config, const char* value) {
     algo = compression_choice_resolve();
     if (algo < 0) {
       log_message(LOG_LEVEL_ERROR, "RSYNC_COMPRESS_LIST names no supported compression algorithm");
-      config->cli_exit_code = 4;
+      config->cli.cli_exit_code = 4;
       return -1;
     }
   } else {
@@ -189,7 +189,7 @@ static int set_compression_choice(Config* config, const char* value) {
                 "--compress-choice '%s' is not a supported algorithm; FastSync supports zstd, "
                 "lz4, zlib, zlibx, none or auto",
                 value);
-    config->cli_exit_code = 4;
+    config->cli.cli_exit_code = 4;
     return -1;
   }
   const char* canonical = compression_algo_name((CompressionAlgo)algo);
@@ -226,7 +226,7 @@ static int resolve_checksum_name(const char* name, size_t len, int* out) {
  * resolves to FastSync's negotiated default (xxh128). */
 static int set_checksum_choice(Config* config, const char* value) {
   if (!value) {
-    config->cli_exit_code = 4;
+    config->cli.cli_exit_code = 4;
     return -1;
   }
   const char* comma = strchr(value, ',');
@@ -244,7 +244,7 @@ static int set_checksum_choice(Config* config, const char* value) {
                 "--checksum-choice '%s' is invalid; FastSync supports xxh64 (or xxhash), xxh128, "
                 "xxh3, md5, md4, sha1, none or auto, optionally as 'transfer,pre-transfer'",
                 value);
-    config->cli_exit_code = 4;
+    config->cli.cli_exit_code = 4;
     return -1;
   }
   int negotiated = -1;
@@ -252,7 +252,7 @@ static int set_checksum_choice(Config* config, const char* value) {
     negotiated = checksum_choice_resolve();
     if (negotiated < 0) {
       log_message(LOG_LEVEL_ERROR, "RSYNC_CHECKSUM_LIST names no supported checksum algorithm");
-      config->cli_exit_code = 4;
+      config->cli.cli_exit_code = 4;
       return -1;
     }
   }
@@ -264,8 +264,8 @@ static int set_checksum_choice(Config* config, const char* value) {
     pre = negotiated;
 
   config->checksum_algo = pre;
-  config->checksum_transfer_algo = transfer;
-  config->checksum_choice_set = true;
+  config->cli.checksum_transfer_algo = transfer;
+  config->cli.checksum_choice_set = true;
   /* rsync: "none" for the transfer checksum forces --whole-file. */
   if (transfer == (int)CHECKSUM_ALGO_NONE)
     config->whole_file = true;
@@ -963,7 +963,10 @@ static const OptionEntry OPTION_TABLE[] = {
      * faithful no-op (accepted silently, never consumes an argument). */
     {"--recursive", "-r", OPT_NOOP, 0},
     {"--update", "-u", OPT_FLAG, offsetof(Config, update)},
-    {"--old-args", NULL, OPT_FLAG, offsetof(Config, old_args)},
+    /* rsync's --old-args: accepted for CLI compatibility as a documented no-op
+     * (the remote server path is always safely quoted; see usage.c).  It is
+     * recognized but stores no Config field. */
+    {"--old-args", NULL, OPT_NOOP, 0},
     {"--rsh", "-e", OPT_STRING, offsetof(Config, rsh_command)},
     {"--blocking-io", NULL, OPT_FLAG, offsetof(Config, blocking_io)},
     {"--links", "-l", OPT_FLAG, offsetof(Config, follow_symlinks)},
@@ -1196,12 +1199,12 @@ static int apply_negation(Config* config, const char* arg) {
     config->preserve_times = false;
     config->preserve_owner = false;
     config->preserve_group = false;
-    config->metadata_explicitly_disabled = true;
+    config->cli.metadata_explicitly_disabled = true;
     /* --no-preserve is an explicit opt-out of the whole bundle: record it so
      * the --incremental/--delta auto-preserve in cli_finalize_config does not
      * silently re-enable perms/times. */
-    config->preserve_perms_explicit_off = true;
-    config->preserve_times_explicit_off = true;
+    config->cli.preserve_perms_explicit_off = true;
+    config->cli.preserve_times_explicit_off = true;
     return 0;
   }
   *(bool*)((char*)config + entry->offset) = false;
@@ -1209,9 +1212,9 @@ static int apply_negation(Config* config, const char* arg) {
    * auto-preserve the OTHER attribute without undoing this one.  A later
    * -p/-t sets the attribute directly; this flag only gates the implication. */
   if (entry->offset == offsetof(Config, preserve_perms))
-    config->preserve_perms_explicit_off = true;
+    config->cli.preserve_perms_explicit_off = true;
   else if (entry->offset == offsetof(Config, preserve_times))
-    config->preserve_times_explicit_off = true;
+    config->cli.preserve_times_explicit_off = true;
   return 0;
 }
 
@@ -1440,7 +1443,7 @@ static bool cli_handle_range_time_options(CliParseCtx* ctx) {
       ctx->exit_code = -1;
       return true;
     }
-    config->stop_at_set = true;
+    config->cli.stop_at_set = true;
     return true;
   }
   if (strcmp(arg, "--stop-at") == 0) {
@@ -1455,7 +1458,7 @@ static bool cli_handle_range_time_options(CliParseCtx* ctx) {
       ctx->exit_code = -1;
       return true;
     }
-    config->stop_at_set = true;
+    config->cli.stop_at_set = true;
     return true;
   }
   const char* threads_prefix = "--compress-threads=";
@@ -1526,7 +1529,7 @@ static bool cli_handle_table_option(CliParseCtx* ctx) {
         return true;
       }
       if (entry->offset == offsetof(Config, compression_level))
-        config->compression_level_set = true;
+        config->cli.compression_level_set = true;
       if (entry->offset == offsetof(Config, chmod_spec)) {
         mode_t ignored;
         if (!chmod_apply(0, config->chmod_spec, &ignored)) {
@@ -1539,7 +1542,7 @@ static bool cli_handle_table_option(CliParseCtx* ctx) {
          defaults to 127.0.0.1, so a value check cannot distinguish it).  Used
          by --dry-run to route an explicit remote target to the server. */
       if (entry->offset == offsetof(Config, server_host))
-        config->server_host_set = true;
+        config->cli.server_host_set = true;
     }
   } else if (apply_table_option(config, entry, NULL) != 0) {
     ctx->exit_code = -1;
@@ -1813,7 +1816,7 @@ static bool cli_handle_transfer_flags(CliParseCtx* ctx) {
           return true;
         }
         config->compression_level = (int)level;
-        config->compression_level_set = true;
+        config->cli.compression_level_set = true;
         log_info_message(LOG_INFO_MISC, "Set Compression level to %ld", level);
         ctx->i++;
       }
@@ -1877,7 +1880,7 @@ static int set_server_port_option(Config* config, const char* value, const char*
     return -1;
   }
   config->server_port = port;
-  config->server_port_set = true;
+  config->cli.server_port_set = true;
   return 0;
 }
 
@@ -2648,7 +2651,7 @@ static int cli_finalize_config(Config* config, bool verbose, bool no_delta, bool
     int resolved = compression_choice_resolve();
     if (resolved < 0) {
       log_message(LOG_LEVEL_ERROR, "RSYNC_COMPRESS_LIST names no supported compression algorithm");
-      config->cli_exit_code = 4;
+      config->cli.cli_exit_code = 4;
       return -1;
     }
     config->compression_algo = resolved;
@@ -2659,7 +2662,7 @@ static int cli_finalize_config(Config* config, bool verbose, bool no_delta, bool
    * clamped to the codec's range, otherwise the codec's own default is used. */
   if (config->use_compression) {
     CompressionAlgo algo = (CompressionAlgo)config->compression_algo;
-    config->compression_level = config->compression_level_set
+    config->compression_level = config->cli.compression_level_set
                                     ? compression_clamp_level(algo, config->compression_level)
                                     : compression_default_level(algo);
     log_debug_message(LOG_DEBUG_UTIL, "Client compression: %s (level %d)",
@@ -2668,22 +2671,22 @@ static int cli_finalize_config(Config* config, bool verbose, bool no_delta, bool
   /* The negotiated checksum is always resolved (rsync negotiates one for the
    * delta strong sum even without --checksum): RSYNC_CHECKSUM_LIST first, then
    * the compiled-in order.  An explicit --checksum-choice already set it. */
-  if (!config->checksum_choice_set) {
+  if (!config->cli.checksum_choice_set) {
     int resolved = checksum_choice_resolve();
     if (resolved < 0) {
       log_message(LOG_LEVEL_ERROR, "RSYNC_CHECKSUM_LIST names no supported checksum algorithm");
-      config->cli_exit_code = 4;
+      config->cli.cli_exit_code = 4;
       return -1;
     }
     config->checksum_algo = resolved;
-    config->checksum_transfer_algo = resolved;
+    config->cli.checksum_transfer_algo = resolved;
   }
   /* rsync parity: "none" as the pre-transfer checksum cannot be combined with
    * --checksum (exit 4).  The check runs here because --checksum may appear on
    * either side of --checksum-choice. */
   if (config->checksum && config->checksum_algo == (int)CHECKSUM_ALGO_NONE) {
     log_message(LOG_LEVEL_ERROR, "Invalid checksum-choice for --checksum: none");
-    config->cli_exit_code = 4;
+    config->cli.cli_exit_code = 4;
     return -1;
   }
 
@@ -2762,11 +2765,11 @@ static int cli_finalize_config(Config* config, bool verbose, bool no_delta, bool
    * explicitly negated them (--no-perms/--no-times/--no-preserve).  This runs
    * BEFORE the derived use_metadata bit so the transport frame is still sent
    * for the incremental/delta handshake even when both attributes were negated
-   * via --no-preserve (metadata_explicitly_disabled handles that opt-out). */
-  if (preserve_implied && !config->metadata_explicitly_disabled) {
-    if (!config->preserve_perms_explicit_off)
+   * via --no-preserve (cli.metadata_explicitly_disabled handles that opt-out). */
+  if (preserve_implied && !config->cli.metadata_explicitly_disabled) {
+    if (!config->cli.preserve_perms_explicit_off)
       config->preserve_perms = true;
-    if (!config->preserve_times_explicit_off)
+    if (!config->cli.preserve_times_explicit_off)
       config->preserve_times = true;
   }
 
@@ -3153,7 +3156,7 @@ int main(int argc, char* argv[]) {
   int parse_ret = parse_args(config, argc, argv, positional_args, &positional_count);
   if (parse_ret != 0) {
     if (parse_ret < 0)
-      exit_code = config->cli_exit_code ? config->cli_exit_code : 1;
+      exit_code = config->cli.cli_exit_code ? config->cli.cli_exit_code : 1;
     goto cleanup;
   }
 

src/client/client_manifest.c

@@ -31,7 +31,7 @@ bool dry_run_targets_server(const Config* config) {
     return true;
   if (config->module && config->module[0] != '\0')
     return true;
-  if (config->server_host_set || config->server_port_set)
+  if (config->cli.server_host_set || config->cli.server_port_set)
     return true;
   if (config->use_tls)
     return true;

src/client/client_send.c

@@ -1578,7 +1578,7 @@ static bool send_files_run(Config* config, SendFilesState* state) {
     now_mono.tv_nsec = 0;
   }
   state->stop = stop_condition_make(config->stop_after_mins > 0, config->stop_after_mins,
-                                    config->stop_at_set, config->stop_at, now_mono);
+                                    config->cli.stop_at_set, config->stop_at, now_mono);
   state->prepared.options.stop_condition = &state->stop;
   /* The early-delete pre-scan above already ran; only the data pass should feed
      the directory-time list (otherwise every directory would be captured
@@ -1653,7 +1653,7 @@ static bool send_files_run(Config* config, SendFilesState* state) {
 /* Completion tail: send the late delete manifest and captured directory times,
  * finalize the receiver handshake, remove transferred sources and report stats.
  * Returns the rsync-compatible exit code. */
-static int send_files_finalize(Config* config, SendFilesState* state) {
+static int send_files_finalize(const Config* config, SendFilesState* state) {
   Client* client = state->client;
   if (directory_scanner_failed(state->scanner))
     return 1;
@@ -1916,8 +1916,8 @@ int send_files_multithreaded(Config* config) {
     now_mono.tv_nsec = 0;
   }
   context->stop_condition =
-      stop_condition_make(config->stop_after_mins > 0, config->stop_after_mins, config->stop_at_set,
-                          config->stop_at, now_mono);
+      stop_condition_make(config->stop_after_mins > 0, config->stop_after_mins,
+                          config->cli.stop_at_set, config->stop_at, now_mono);
   bool collect_excluded = config->use_delete && !config->delete_excluded;
   unsigned long long pre_scan_non_dir = 0;
   if (config->use_delete) {

src/server/receiver.c

@@ -303,6 +303,264 @@ int receiver_process(Config* config, int file_descriptor, const ReceiverSink* si
   return receiver_process_pending(config, file_descriptor, sink, NULL, NULL);
 }
 
+/* Per-connection state threaded through the status handlers below.  The parked
+   keep-set / per-directory session live here so one teardown helper can release
+   them on every exit path. */
+typedef struct {
+  Config* config;
+  int fd;
+  const ReceiverSink* sink;
+  DeleteManifest** pending_manifest;
+  DeletePlanSession** pending_plans;
+  /* Parked keep-set for the late/commit timing.  Every exit path frees it
+     exactly once; the only exception is the successful FINISHED handoff, which
+     transfers ownership to *pending_manifest (used by the -m receiver). */
+  DeleteManifest* deferred_manifest;
+  /* Per-directory delete session for --delete-during/--delete-delay.  During the
+     loop it applies plans inline (during) or snapshots their extras (delay); on
+     a successful FINISHED it is either committed here or handed to
+     *pending_plans so the -m caller commits after its disk writer drained. */
+  DeletePlanSession* plan_session;
+  bool early_delete;
+  bool per_dir_delete;
+  bool delete_limit_noted;
+} ReceiverPendingState;
+
+/* Outcome of one frame handler.  NEXT reads the following status frame; FAIL
+   tears the connection down without a peer STATUS_ERROR; ERROR tears it down
+   and (when the sink owns error reporting) emits STATUS_ERROR. */
+typedef enum {
+  RECEIVER_STEP_NEXT,
+  RECEIVER_STEP_FAIL,
+  RECEIVER_STEP_ERROR,
+} ReceiverStep;
+
+static ReceiverStep receiver_handle_keepalive(ReceiverPendingState* state) {
+  if (!send_status(state->fd, STATUS_KEEPALIVE))
+    return RECEIVER_STEP_FAIL;
+  return RECEIVER_STEP_NEXT;
+}
+
+static ReceiverStep receiver_handle_abort(ReceiverPendingState* state) {
+  (void)state;
+  log_message(LOG_LEVEL_INFO, "Received abort from client, cleaning up");
+  return RECEIVER_STEP_FAIL;
+}
+
+static ReceiverStep receiver_handle_check(ReceiverPendingState* state) {
+  bool skipped = false;
+  bool would_transfer = false;
+  File* file = receive_incremental_check_ex(state->fd, state->config, &skipped, &would_transfer);
+  if (state->config->dry_run) {
+    /* Server-contacting --dry-run: the reply has already been sent
+       (STATUS_OK = up to date, STATUS_DRY_RUN_TRANSFER = would transfer) and
+       nothing may be stored.  Both flags false means a genuine protocol
+       error (STATUS_ERROR already sent or sent by receive_error below). */
+    if (!skipped && !would_transfer)
+      return RECEIVER_STEP_ERROR;
+  } else if (!skipped && (!file || !state->sink->store_file(file, state->sink->context))) {
+    return RECEIVER_STEP_ERROR;
+  }
+  return RECEIVER_STEP_NEXT;
+}
+
+static ReceiverStep receiver_handle_chunk(ReceiverPendingState* state) {
+  Chunk* chunk = receive_chunk_data(state->fd, state->config);
+  if (!chunk || !receiver_process_chunk(chunk, state->sink))
+    return RECEIVER_STEP_ERROR;
+  return RECEIVER_STEP_NEXT;
+}
+
+static ReceiverStep receiver_handle_check_batch(ReceiverPendingState* state) {
+  if (!receiver_process_batch(state->config, state->fd))
+    return RECEIVER_STEP_FAIL;
+  return RECEIVER_STEP_NEXT;
+}
+
+static ReceiverStep receiver_handle_mkdir(ReceiverPendingState* state) {
+  File* dir = file_receive_directory(state->fd, state->config);
+  if (!dir || !state->sink->store_file(dir, state->sink->context))
+    return RECEIVER_STEP_ERROR;
+  return RECEIVER_STEP_NEXT;
+}
+
+static ReceiverStep receiver_handle_dir_times(const ReceiverPendingState* state) {
+  if (!receiver_process_dir_times(state->fd, state->config, state->sink))
+    return RECEIVER_STEP_ERROR;
+  return RECEIVER_STEP_NEXT;
+}
+
+static ReceiverStep receiver_handle_hardlink(ReceiverPendingState* state) {
+  File* file = file_receive_hardlink(state->fd);
+  if (!file || !state->sink->store_file(file, state->sink->context))
+    return RECEIVER_STEP_ERROR;
+  return RECEIVER_STEP_NEXT;
+}
+
+static ReceiverStep receiver_handle_symlink(ReceiverPendingState* state) {
+  File* sym = file_receive_symlink(state->fd, state->config);
+  if (!sym || !state->sink->store_file(sym, state->sink->context))
+    return RECEIVER_STEP_ERROR;
+  return RECEIVER_STEP_NEXT;
+}
+
+static ReceiverStep receiver_handle_special(ReceiverPendingState* state) {
+  File* file = file_receive_special(state->fd);
+  if (!file || !state->sink->store_file(file, state->sink->context))
+    return RECEIVER_STEP_ERROR;
+  return RECEIVER_STEP_NEXT;
+}
+
+static ReceiverStep receiver_handle_manifest(ReceiverPendingState* state) {
+  Config* config = state->config;
+  int fd = state->fd;
+  const ReceiverSink* sink = state->sink;
+  DeleteManifest* manifest = receive_manifest_entries(fd);
+  if (!manifest)
+    return RECEIVER_STEP_FAIL; /* receive_manifest_entries already sent STATUS_ERROR */
+  if (config->dry_run) {
+    /* Server-contacting --dry-run mutates nothing, so a keep-set manifest
+       is consumed and discarded.  The early-delete mode still needs its ACK
+       so a sender blocked on the delete handshake is not left hanging.
+       When would-delete reporting is armed, enumerate (read-only) the
+       destination extras so the terminal STATUS_STATS frame can list them. */
+    if (config->use_delete && sink->would_delete) {
+      size_t count = 0;
+      if (!manifest_would_delete_list(config, manifest, sink->would_delete, &count))
+        log_message(LOG_LEVEL_WARNING, "dry-run: could not enumerate would-delete paths");
+    }
+    delete_manifest_free(manifest);
+    if (state->early_delete && !send_status(fd, STATUS_OK))
+      return RECEIVER_STEP_FAIL;
+    return RECEIVER_STEP_NEXT;
+  }
+  if (state->early_delete) {
+    /* --delete-before: the whole-tree manifest is authoritative the moment
+       it arrives, before any file data.  Delete now and acknowledge so the
+       sender only starts streaming once the deletion committed (or failed).
+       A later transfer failure does not restore these deletions.  A
+       --max-delete-capped commit still succeeds and the transfer proceeds;
+       the terminal success frame reports the cap. */
+    size_t deleted = 0;
+    DeletePathObserver observer =
+        (config->report_deletes && sink->deleted_paths) ? receiver_record_deleted_path : NULL;
+    DeleteCommitResult deletion =
+        (config->use_delete || config->delete_missing_args)
+            ? manifest_delete_all_observed(config, manifest, &deleted, observer,
+                                           (void*)sink->deleted_paths)
+            : DELETE_COMMIT_OK;
+    receiver_tally_deleted(sink, deleted);
+    delete_manifest_free(manifest);
+    if (deletion == DELETE_COMMIT_ERROR) {
+      send_status(fd, STATUS_ERROR);
+      return RECEIVER_STEP_FAIL;
+    }
+    if (deletion == DELETE_COMMIT_LIMIT_REACHED && sink->note_delete_limit)
+      sink->note_delete_limit(sink->context);
+    if (!send_status(fd, STATUS_OK))
+      return RECEIVER_STEP_FAIL;
+  } else if (config->use_delete || config->delete_missing_args) {
+    /* Plain --delete / --delete-after and the --delete-missing-args
+       exact-path deletions: hold the manifest and commit it only after
+       STATUS_FINISHED.  The per-directory modes never send this frame. */
+    if (state->deferred_manifest) {
+      log_message(LOG_LEVEL_ERROR, "Received a second delete manifest");
+      delete_manifest_free(state->deferred_manifest);
+      state->deferred_manifest = NULL;
+      delete_manifest_free(manifest);
+      send_status(fd, STATUS_ERROR);
+      return RECEIVER_STEP_FAIL;
+    }
+    state->deferred_manifest = manifest;
+  } else {
+    delete_manifest_free(manifest);
+  }
+  return RECEIVER_STEP_NEXT;
+}
+
+static ReceiverStep receiver_handle_delete_plan(ReceiverPendingState* state) {
+  Config* config = state->config;
+  int fd = state->fd;
+  const ReceiverSink* sink = state->sink;
+  if (!state->per_dir_delete) {
+    log_message(LOG_LEVEL_ERROR, "Received a per-directory delete plan without a per-dir "
+                                 "delete timing");
+    send_status(fd, STATUS_ERROR);
+    return RECEIVER_STEP_FAIL;
+  }
+  if (!state->plan_session) {
+    state->plan_session = delete_plan_session_create(config);
+    if (state->plan_session && config->report_deletes && sink->deleted_paths)
+      delete_plan_session_set_delete_observer(state->plan_session, receiver_record_deleted_path,
+                                              (void*)sink->deleted_paths);
+  }
+  if (!state->plan_session || delete_plan_session_receive(state->plan_session, config, fd) != 0)
+    return RECEIVER_STEP_FAIL;
+  if (delete_plan_session_limit_reached(state->plan_session) && !state->delete_limit_noted &&
+      sink->note_delete_limit) {
+    sink->note_delete_limit(sink->context);
+    state->delete_limit_noted = true;
+  }
+  return RECEIVER_STEP_NEXT;
+}
+
+static ReceiverStep receiver_handle_file(ReceiverPendingState* state) {
+  File* file = file_receive(state->config, state->fd);
+  if (!file) {
+    log_message(LOG_LEVEL_ERROR, "Failed to receive file");
+    return RECEIVER_STEP_ERROR;
+  }
+  if (!state->sink->store_file(file, state->sink->context))
+    return RECEIVER_STEP_ERROR;
+  return RECEIVER_STEP_NEXT;
+}
+
+/* One dispatch per admitted frame type; STATUS_NEXT (and any other
+   data-bearing status) falls through to the regular file receiver. */
+static ReceiverStep receiver_dispatch_status(ReceiverPendingState* state, Status status) {
+  switch (status) {
+  case STATUS_KEEPALIVE:
+    return receiver_handle_keepalive(state);
+  case STATUS_ABORT:
+    return receiver_handle_abort(state);
+  case STATUS_CHECK:
+    return receiver_handle_check(state);
+  case STATUS_CHUNK:
+    return receiver_handle_chunk(state);
+  case STATUS_CHECK_BATCH:
+    return receiver_handle_check_batch(state);
+  case STATUS_MKDIR:
+    return receiver_handle_mkdir(state);
+  case STATUS_DIR_TIMES:
+    return receiver_handle_dir_times(state);
+  case STATUS_HARDLINK:
+    return receiver_handle_hardlink(state);
+  case STATUS_SYMLINK:
+    return receiver_handle_symlink(state);
+  case STATUS_SPECIAL:
+    return receiver_handle_special(state);
+  case STATUS_MANIFEST:
+    return receiver_handle_manifest(state);
+  case STATUS_DELETE_PLAN:
+    return receiver_handle_delete_plan(state);
+  default:
+    return receiver_handle_file(state);
+  }
+}
+
+/* Release the parked keep-set / per-directory session exactly once on every
+   failure exit.  Never commit a deletion for a failed stream. */
+static void receiver_drop_pending(ReceiverPendingState* state) {
+  if (state->deferred_manifest) {
+    delete_manifest_free(state->deferred_manifest);
+    state->deferred_manifest = NULL;
+  }
+  if (state->plan_session) {
+    delete_plan_session_destroy(state->plan_session);
+    state->plan_session = NULL;
+  }
+}
+
 /* Runs the whole receive loop.  The delete manifest may legitimately arrive
    either FIRST (--delete-before / --delete-during: the sender transmits the
    validated keep-set before any file data) or LAST (--delete-after /
@@ -312,9 +570,9 @@ int receiver_process(Config* config, int file_descriptor, const ReceiverSink* si
    deletion has committed (or failed); in the late modes the manifest is held
    and the deletion is committed only after the terminal STATUS_FINISHED proves
    the whole transfer succeeded.  A plain --delete defaults to the per-directory
-   delete-during plan mode (no manifest at all).  See
-   receiver_process_pending() for how the -m receiver defers that commit until
-   its disk writer has drained. */
+   delete-during plan mode (no manifest at all).  See the per-frame handlers
+   above for how the -m receiver defers that commit until its disk writer has
+   drained. */
 int receiver_process_pending(Config* config, int file_descriptor, const ReceiverSink* sink,
                              DeleteManifest** pending_manifest, DeletePlanSession** pending_plans) {
   Status status;
@@ -329,166 +587,29 @@ int receiver_process_pending(Config* config, int file_descriptor, const Receiver
   last_progress = session_start;
   if (!receiver_note_status(&session_start, &last_progress, status, file_descriptor, sink))
     return -1;
-  bool early_delete = config_delete_timing_early(config);
-  bool per_dir_delete = config_delete_timing_per_dir(config);
-  /* Parked keep-set for the late/commit timing.  Every exit path below frees it
-     exactly once; the only exception is the successful FINISHED handoff, which
-     transfers ownership to *pending_manifest (used by the -m receiver). */
-  DeleteManifest* deferred_manifest = NULL;
-  /* Per-directory delete session for --delete-during/--delete-delay.  During the
-     loop it applies plans inline (during) or snapshots their extras (delay); on
-     a successful FINISHED it is either committed here or handed to
-     *pending_plans so the -m caller commits after its disk writer drained. */
-  DeletePlanSession* plan_session = NULL;
-  bool delete_limit_noted = false;
+  ReceiverPendingState state = {
+      .config = config,
+      .fd = file_descriptor,
+      .sink = sink,
+      .pending_manifest = pending_manifest,
+      .pending_plans = pending_plans,
+      .deferred_manifest = NULL,
+      .plan_session = NULL,
+      .early_delete = config_delete_timing_early(config),
+      .per_dir_delete = config_delete_timing_per_dir(config),
+      .delete_limit_noted = false,
+  };
+  bool notify_peer = false;
   while (status == STATUS_NEXT || status == STATUS_CHUNK || status == STATUS_CHECK ||
          status == STATUS_KEEPALIVE || status == STATUS_ABORT || status == STATUS_CHECK_BATCH ||
          status == STATUS_MKDIR || status == STATUS_MANIFEST || status == STATUS_HARDLINK ||
          status == STATUS_SYMLINK || status == STATUS_SPECIAL || status == STATUS_DIR_TIMES ||
          status == STATUS_DELETE_PLAN) {
-    if (status == STATUS_KEEPALIVE) {
-      if (!send_status(file_descriptor, STATUS_KEEPALIVE))
-        goto fail;
-      goto next_status;
-    }
-    if (status == STATUS_ABORT) {
-      log_message(LOG_LEVEL_INFO, "Received abort from client, cleaning up");
+    ReceiverStep step = receiver_dispatch_status(&state, status);
+    if (step == RECEIVER_STEP_FAIL)
       goto fail;
-    }
-    if (status == STATUS_CHECK) {
-      bool skipped = false;
-      bool would_transfer = false;
-      File* file = receive_incremental_check_ex(file_descriptor, config, &skipped, &would_transfer);
-      if (config->dry_run) {
-        /* Server-contacting --dry-run: the reply has already been sent
-           (STATUS_OK = up to date, STATUS_DRY_RUN_TRANSFER = would transfer) and
-           nothing may be stored.  Both flags false means a genuine protocol
-           error (STATUS_ERROR already sent or sent by receive_error below). */
-        if (!skipped && !would_transfer)
-          goto receive_error;
-      } else if (!skipped && (!file || !sink->store_file(file, sink->context))) {
-        goto receive_error;
-      }
-    } else if (status == STATUS_CHUNK) {
-      Chunk* chunk = receive_chunk_data(file_descriptor, config);
-      if (!chunk || !receiver_process_chunk(chunk, sink))
-        goto receive_error;
-    } else if (status == STATUS_CHECK_BATCH) {
-      if (!receiver_process_batch(config, file_descriptor))
-        goto fail;
-      goto next_status;
-    } else if (status == STATUS_MKDIR) {
-      File* dir = file_receive_directory(file_descriptor, config);
-      if (!dir || !sink->store_file(dir, sink->context))
-        goto receive_error;
-    } else if (status == STATUS_DIR_TIMES) {
-      if (!receiver_process_dir_times(file_descriptor, config, sink))
-        goto receive_error;
-    } else if (status == STATUS_HARDLINK) {
-      File* file = file_receive_hardlink(file_descriptor);
-      if (!file || !sink->store_file(file, sink->context))
-        goto receive_error;
-    } else if (status == STATUS_SYMLINK) {
-      File* sym = file_receive_symlink(file_descriptor, config);
-      if (!sym || !sink->store_file(sym, sink->context))
-        goto receive_error;
-    } else if (status == STATUS_SPECIAL) {
-      File* file = file_receive_special(file_descriptor);
-      if (!file || !sink->store_file(file, sink->context))
-        goto receive_error;
-    } else if (status == STATUS_MANIFEST) {
-      DeleteManifest* manifest = receive_manifest_entries(file_descriptor);
-      if (!manifest)
-        goto fail; /* receive_manifest_entries already sent STATUS_ERROR */
-      if (config->dry_run) {
-        /* Server-contacting --dry-run mutates nothing, so a keep-set manifest
-           is consumed and discarded.  The early-delete mode still needs its ACK
-           so a sender blocked on the delete handshake is not left hanging.
-           When would-delete reporting is armed, enumerate (read-only) the
-           destination extras so the terminal STATUS_STATS frame can list them. */
-        if (config->use_delete && sink->would_delete) {
-          size_t count = 0;
-          if (!manifest_would_delete_list(config, manifest, sink->would_delete, &count))
-            log_message(LOG_LEVEL_WARNING, "dry-run: could not enumerate would-delete paths");
-        }
-        delete_manifest_free(manifest);
-        if (early_delete && !send_status(file_descriptor, STATUS_OK))
-          goto fail;
-        goto next_status;
-      }
-      if (early_delete) {
-        /* --delete-before: the whole-tree manifest is authoritative the moment
-           it arrives, before any file data.  Delete now and acknowledge so the
-           sender only starts streaming once the deletion committed (or failed).
-           A later transfer failure does not restore these deletions.  A
-           --max-delete-capped commit still succeeds and the transfer proceeds;
-           the terminal success frame reports the cap. */
-        size_t deleted = 0;
-        DeletePathObserver observer =
-            (config->report_deletes && sink->deleted_paths) ? receiver_record_deleted_path : NULL;
-        DeleteCommitResult deletion =
-            (config->use_delete || config->delete_missing_args)
-                ? manifest_delete_all_observed(config, manifest, &deleted, observer,
-                                               (void*)sink->deleted_paths)
-                : DELETE_COMMIT_OK;
-        receiver_tally_deleted(sink, deleted);
-        delete_manifest_free(manifest);
-        if (deletion == DELETE_COMMIT_ERROR) {
-          send_status(file_descriptor, STATUS_ERROR);
-          goto fail;
-        }
-        if (deletion == DELETE_COMMIT_LIMIT_REACHED && sink->note_delete_limit)
-          sink->note_delete_limit(sink->context);
-        if (!send_status(file_descriptor, STATUS_OK))
-          goto fail;
-      } else if (config->use_delete || config->delete_missing_args) {
-        /* Plain --delete / --delete-after and the --delete-missing-args
-           exact-path deletions: hold the manifest and commit it only after
-           STATUS_FINISHED.  The per-directory modes never send this frame. */
-        if (deferred_manifest) {
-          log_message(LOG_LEVEL_ERROR, "Received a second delete manifest");
-          delete_manifest_free(deferred_manifest);
-          deferred_manifest = NULL;
-          delete_manifest_free(manifest);
-          send_status(file_descriptor, STATUS_ERROR);
-          goto fail;
-        }
-        deferred_manifest = manifest;
-      } else {
-        delete_manifest_free(manifest);
-      }
-      goto next_status;
-    } else if (status == STATUS_DELETE_PLAN) {
-      if (!per_dir_delete) {
-        log_message(LOG_LEVEL_ERROR, "Received a per-directory delete plan without a per-dir "
-                                     "delete timing");
-        send_status(file_descriptor, STATUS_ERROR);
-        goto fail;
-      }
-      if (!plan_session) {
-        plan_session = delete_plan_session_create(config);
-        if (plan_session && config->report_deletes && sink->deleted_paths)
-          delete_plan_session_set_delete_observer(plan_session, receiver_record_deleted_path,
-                                                  (void*)sink->deleted_paths);
-      }
-      if (!plan_session || delete_plan_session_receive(plan_session, config, file_descriptor) != 0)
-        goto fail;
-      if (delete_plan_session_limit_reached(plan_session) && !delete_limit_noted &&
-          sink->note_delete_limit) {
-        sink->note_delete_limit(sink->context);
-        delete_limit_noted = true;
-      }
-      goto next_status;
-    } else {
-      File* file = file_receive(config, file_descriptor);
-      if (!file) {
-        log_message(LOG_LEVEL_ERROR, "Failed to receive file");
-        goto receive_error;
-      }
-      if (!sink->store_file(file, sink->context))
-        goto receive_error;
-    }
-  next_status:
+    if (step == RECEIVER_STEP_ERROR)
+      goto receive_error;
     if (!receive_status(file_descriptor, &status))
       goto receive_error;
     if (!receiver_note_status(&session_start, &last_progress, status, file_descriptor, sink))
@@ -507,19 +628,19 @@ int receiver_process_pending(Config* config, int file_descriptor, const Receiver
      disk writer may still be draining; the caller commits after the writer has
      joined so no extra file is removed unless the transfer is known to have
      succeeded. */
-  if (deferred_manifest) {
-    if (pending_manifest) {
-      *pending_manifest = deferred_manifest;
-      deferred_manifest = NULL;
+  if (state.deferred_manifest) {
+    if (state.pending_manifest) {
+      *state.pending_manifest = state.deferred_manifest;
+      state.deferred_manifest = NULL;
     } else {
       size_t deleted = 0;
       DeletePathObserver observer =
           (config->report_deletes && sink->deleted_paths) ? receiver_record_deleted_path : NULL;
       DeleteCommitResult deletion = manifest_delete_all_observed(
-          config, deferred_manifest, &deleted, observer, (void*)sink->deleted_paths);
+          config, state.deferred_manifest, &deleted, observer, (void*)sink->deleted_paths);
       receiver_tally_deleted(sink, deleted);
-      delete_manifest_free(deferred_manifest);
-      deferred_manifest = NULL;
+      delete_manifest_free(state.deferred_manifest);
+      state.deferred_manifest = NULL;
       if (deletion == DELETE_COMMIT_ERROR) {
         send_status(file_descriptor, STATUS_ERROR);
         goto fail;
@@ -533,28 +654,28 @@ int receiver_process_pending(Config* config, int file_descriptor, const Receiver
      nothing yet and applies its decompressed snapshot here.  The -m receiver
      hands the session to its caller instead, which commits after the disk
      writer drained. */
-  if (plan_session) {
+  if (state.plan_session) {
     if (config->report_deletes && sink->deleted_paths)
-      delete_plan_session_set_delete_observer(plan_session, receiver_record_deleted_path,
+      delete_plan_session_set_delete_observer(state.plan_session, receiver_record_deleted_path,
                                               (void*)sink->deleted_paths);
-    if (pending_plans) {
-      *pending_plans = plan_session;
-      plan_session = NULL;
+    if (state.pending_plans) {
+      *state.pending_plans = state.plan_session;
+      state.plan_session = NULL;
     } else if (config->dry_run) {
       /* Central dry-run no-op: never commit a deletion for a -n run. */
-      delete_plan_session_destroy(plan_session);
-      plan_session = NULL;
+      delete_plan_session_destroy(state.plan_session);
+      state.plan_session = NULL;
     } else {
-      DeleteCommitResult deletion = delete_plan_session_commit(plan_session, config);
-      bool limit = delete_plan_session_limit_reached(plan_session);
-      receiver_tally_deleted(sink, delete_plan_session_deleted(plan_session));
-      delete_plan_session_destroy(plan_session);
-      plan_session = NULL;
+      DeleteCommitResult deletion = delete_plan_session_commit(state.plan_session, config);
+      bool limit = delete_plan_session_limit_reached(state.plan_session);
+      receiver_tally_deleted(sink, delete_plan_session_deleted(state.plan_session));
+      delete_plan_session_destroy(state.plan_session);
+      state.plan_session = NULL;
       if (deletion == DELETE_COMMIT_ERROR) {
         send_status(file_descriptor, STATUS_ERROR);
         goto fail;
       }
-      if (limit && !delete_limit_noted && sink->note_delete_limit)
+      if (limit && !state.delete_limit_noted && sink->note_delete_limit)
         sink->note_delete_limit(sink->context);
     }
   }
@@ -568,26 +689,14 @@ int receiver_process_pending(Config* config, int file_descriptor, const Receiver
   }
   return 0;
 
+receive_error:
+  notify_peer = true;
 fail:
   /* Failure exits that must not (or already did) report a STATUS_ERROR.  The
      parked keep-set/session is dropped: never commit a deletion for a failed
      stream. */
-  if (deferred_manifest) {
-    delete_manifest_free(deferred_manifest);
-    deferred_manifest = NULL;
-  }
-  if (plan_session)
-    delete_plan_session_destroy(plan_session);
-  return -1;
-
-receive_error:
-  if (deferred_manifest) {
-    delete_manifest_free(deferred_manifest);
-    deferred_manifest = NULL;
-  }
-  if (plan_session)
-    delete_plan_session_destroy(plan_session);
-  if (sink->send_error)
+  receiver_drop_pending(&state);
+  if (notify_peer && sink->send_error)
     send_status(file_descriptor, STATUS_ERROR);
   return -1;
 }

src/server/server.c

@@ -705,69 +705,85 @@ static const char* server_module_gate(const Config* config, void* context) {
   return module_gate_install_root(config, module);
 }
 
-void handler(int file_descriptor) {
-  SSL* ssl = io_get_ssl();
+/* Per-connection state threaded through the handler phase helpers below.  The
+ * fields are a faithful split of the former handler() locals: the protocol
+ * session, the config-frame gate context, the accepted config, the optional
+ * multithreaded pipeline context and the teardown bookkeeping all live here so
+ * the single `done` epilogue in handler() can release them exactly as before. */
+typedef struct ServerSession {
+  int fd;
+  SSL* ssl;
   ProtocolSession session;
-  protocol_session_init(&session, file_descriptor, file_descriptor);
-  protocol_session_set_ssl(&session, ssl);
-  protocol_session_bind(&session);
   ModuleGateContext gate_ctx;
-  gate_ctx.ssl = ssl;
-  gate_ctx.fd = file_descriptor;
-  gate_ctx.super_mode_override = -1;
-  gate_ctx.has_peer_ip = false;
-  gate_ctx.peer_ip[0] = '\0';
-  gate_ctx.is_local = false;
-  /* All teardown state starts empty so the single `done` epilogue is safe to
-   * reach from any error path (including before the config frame arrives). */
-  Config* config = NULL;
-  PipelineContextReceiver* context = NULL;
-  char* joined_destination = NULL;
-  bool charset_ready = false;
-  config = config_receive_with_validate(file_descriptor, server_module_gate, &gate_ctx);
-  if (config == NULL) {
+  Config* config;
+  PipelineContextReceiver* context;
+  char* joined_destination;
+  bool charset_ready;
+} ServerSession;
+
+/* Phase 1 -- config receipt + validation.  Receives the client config frame
+ * through the module gate, applies the super-mode override the gate recorded
+ * exactly once, and installs the per-connection protocol/compression state.
+ * Returns false when the config frame was refused (the gate has already
+ * answered the client); the caller jumps to the shared `done` epilogue. */
+static bool server_accept_config(ServerSession* state) {
+  state->config = config_receive_with_validate(state->fd, server_module_gate, &state->gate_ctx);
+  if (state->config == NULL) {
     log_message(LOG_LEVEL_ERROR, "Failed to receive config");
-    goto done;
+    return false;
   }
   /* Apply the super-mode veto the gate decided on (operator --no-super, or a
    * daemon module without the `client owner = yes` opt-in) exactly once, so
    * every downstream gate (identity_apply_ownership via privilege_super_permitted,
    * device-node creation) sees SUPER_MODE_OFF.  The gate never mutated the
    * received config. */
-  if (gate_ctx.super_mode_override != -1)
-    config->super_mode = (SuperMode)gate_ctx.super_mode_override;
+  if (state->gate_ctx.super_mode_override != -1)
+    state->config->super_mode = (SuperMode)state->gate_ctx.super_mode_override;
   /* Install the codec this connection negotiated before the receiver/writer
    * threads start (the server forks per connection, so the process-global
    * codec is private to this session). */
-  compression_set_algo((CompressionAlgo)config->compression_algo);
+  compression_set_algo((CompressionAlgo)state->config->compression_algo);
   /* If the client requested ownership but the effective super mode forbids it
    * (operator --no-super, a privileged standalone receiver's secure default, or
    * a daemon module without `client owner = yes`), say so ONCE per connection so
    * a successful -a/-o/-g transfer is not mistaken for preserved ownership. */
-  if (config->super_mode == SUPER_MODE_OFF && identity_ownership_requested(config))
+  if (state->config->super_mode == SUPER_MODE_OFF && identity_ownership_requested(state->config))
     log_message(LOG_LEVEL_WARNING,
                 "requested ownership will NOT be applied: super-user activities are disabled "
                 "for this connection (operator veto, or module without `client owner = yes`)");
-  protocol_set_8_bit_output(config->eight_bit_output);
+  protocol_set_8_bit_output(state->config->eight_bit_output);
   /* Server-side per-message protocol deadline for every frame from here on.
    * `timeout` is not serialized, so this is the server's own config (the server
    * has no --timeout CLI and defaults it to 0).  A client's --timeout tightens
    * only that client's own protocol I/O; the server floors its own deadline at
    * SERVER_IO_TIMEOUT_SEC so a silent peer can never hold a session slot
    * forever (the socket layer gets the same floor at startup). */
-  protocol_session_set_io_timeout(&session, protocol_server_io_timeout_sec(config->timeout));
+  protocol_session_set_io_timeout(&state->session,
+                                  protocol_server_io_timeout_sec(state->config->timeout));
+  return true;
+}
+
+/* Phase 2 -- security gates.  The ORDER here is load-bearing and must not be
+ * merged or reordered: transport/authentication (plaintext refusal, TLS
+ * client-CN verification), then daemon-root confinement (absolute-destination
+ * rejection, traversal + within-authorized-root), then delete/force
+ * authorization -- exactly the sequence the former handler() used.  Returns
+ * false after logging the matching rejection; the caller jumps to the shared
+ * `done` epilogue. */
+static bool server_apply_security_gates(ServerSession* state) {
+  Config* config = state->config;
   const char* authorized_root = utils_get_authorized_root_path();
   if (!authorized_root) {
     log_message(LOG_LEVEL_ERROR, "No server-side destination root configured");
-    goto done;
+    return false;
   }
-  if (!allow_unauthenticated && ssl == NULL) {
+  if (!allow_unauthenticated && state->ssl == NULL) {
     log_message(LOG_LEVEL_ERROR, "Rejected unauthenticated plaintext connection");
-    goto done;
+    return false;
   }
-  if (ssl && required_client_cn && !tls_client_identity_allowed(ssl)) {
+  if (state->ssl && required_client_cn && !tls_client_identity_allowed(state->ssl)) {
     log_message(LOG_LEVEL_ERROR, "Rejected TLS client with unauthorized identity");
-    goto done;
+    return false;
   }
   /* Daemon mode: the module's root is the authorized root (installed by
      server_module_gate), and the client's destination is a MODULE-RELATIVE
@@ -777,27 +793,27 @@ void handler(int file_descriptor) {
   if (g_daemon_conf && config->receive_root_directory && config->receive_root_directory[0] == '/') {
     log_message(LOG_LEVEL_ERROR, "Rejected absolute daemon destination (must be relative to the "
                                  "selected module root)");
-    goto done;
+    return false;
   }
   char* destination = config->receive_root_directory;
   if (destination && destination[0] != '/')
-    joined_destination = path_cat(authorized_root, destination);
-  if (joined_destination)
-    destination = joined_destination;
+    state->joined_destination = path_cat(authorized_root, destination);
+  if (state->joined_destination)
+    destination = state->joined_destination;
   if (!destination || has_path_traversal(destination) ||
       !path_is_within_root(authorized_root, destination)) {
     log_message(LOG_LEVEL_ERROR, "Rejected destination outside authorized root");
-    free(joined_destination);
-    joined_destination = NULL;
-    goto done;
+    free(state->joined_destination);
+    state->joined_destination = NULL;
+    return false;
   }
-  if (joined_destination) {
+  if (state->joined_destination) {
     free(config->receive_root_directory);
-    config->receive_root_directory = joined_destination;
-    joined_destination = NULL;
+    config->receive_root_directory = state->joined_destination;
+    state->joined_destination = NULL;
   }
   if (!config->receive_root_directory) {
-    goto done;
+    return false;
   }
   config->use_delete = config->use_delete && allow_delete;
   /* --force (receiver-side) is deletion authority too: it lets an incoming
@@ -807,6 +823,18 @@ void handler(int file_descriptor) {
    * --delete-missing-args, so a client cannot use --force to bypass the delete
    * policy. */
   config->force_delete = config->force_delete && allow_delete;
+  return true;
+}
+
+/* Phase 3 -- session preparation.  Installs the negotiated conversion, applies
+ * the remaining deletion policy, materializes the destination root (--mkpath),
+ * creates the --delay-updates staging tree, snapshots the identity policy, and
+ * publishes the --keep-dirlinks/--trust-sender globals and the daemon MOTD.
+ * All of it must happen before any receiver/writer thread is spawned.  Returns
+ * false after logging the matching failure; the caller jumps to the shared
+ * `done` epilogue. */
+static bool server_prepare_session(ServerSession* state) {
+  Config* config = state->config;
   /* --iconv (protocol 2.16.0): install the receiver-side wire->local conversion
      now that the client's full CONVERT_SPEC has been received and validated,
      before any received file name is decoded.  The server's own --iconv (if
@@ -817,14 +845,14 @@ void handler(int file_descriptor) {
     if (!charset_wire_init_receiver(config->iconv_spec, server_iconv_spec)) {
       log_message(LOG_LEVEL_ERROR,
                   "--iconv: unsupported charset conversion requested (LOCAL[,REMOTE])");
-      goto done;
+      return false;
     }
-    charset_ready = true;
+    state->charset_ready = true;
   }
   /* --delete-missing-args deletes destination mirrors receiver-side, so it is
-     deletion and stays gated by the same --allow-delete server policy.  When
-     the server policy is off the flag is inert (the missing entries are still
-     skipped via its implied --ignore-missing-args, but nothing is deleted). */
+   * deletion and stays gated by the same --allow-delete server policy.  When
+   * the server policy is off the flag is inert (the missing entries are still
+   * skipped via its implied --ignore-missing-args, but nothing is deleted). */
   config->delete_missing_args = config->delete_missing_args && allow_delete;
   /* --mkpath: create the destination root (and its missing leading components)
    * before anything else; without it the root must pre-exist.  The precondition
@@ -839,7 +867,7 @@ void handler(int file_descriptor) {
     log_message(LOG_LEVEL_ERROR, "destination root is not available: %s",
                 escaped_root ? escaped_root : "<allocation failed>");
     free(escaped_root);
-    goto done;
+    return false;
   }
   /* A --delay-updates transfer stages under a private 0700 directory inside
      the receive root.  Create it up front (wiping leftovers of any previously
@@ -849,7 +877,7 @@ void handler(int file_descriptor) {
     config->delay_context = delay_updates_context_create(config->receive_root_directory);
     if (!config->delay_context || !delay_updates_prepare(config->delay_context)) {
       log_message(LOG_LEVEL_ERROR, "Failed to initialize --delay-updates staging area");
-      goto done;
+      return false;
     }
   }
   /* Preserve the negotiated identity policy for the fd-relative ownership
@@ -859,7 +887,7 @@ void handler(int file_descriptor) {
      rather than silently applying the wrong ownership policy. */
   if (!identity_set_active(config)) {
     log_message(LOG_LEVEL_ERROR, "Failed to activate identity policy");
-    goto done;
+    return false;
   }
   /* Persist the negotiated --keep-dirlinks policy once, here at config-accept,
      before any multithreaded receiver/writer threads are spawned, so the
@@ -887,140 +915,195 @@ void handler(int file_descriptor) {
      Wave C note in config.h). */
   if (g_daemon_conf) {
     char* motd = motd_read_file(g_daemon_conf->global.motd_file);
-    if (!motd_send(file_descriptor, motd ? motd : "")) {
+    if (!motd_send(state->fd, motd ? motd : "")) {
       free(motd);
       log_message(LOG_LEVEL_ERROR, "Failed to send daemon MOTD");
-      goto done;
+      return false;
     }
     free(motd);
   }
-  if (config->use_multithreading) {
-    Queue* q = queue_create(100, file_destroy);
-    if (q == NULL)
-      goto done;
-    context = pipeline_context_receiver_create(config, q, file_descriptor, ssl);
-    if (context == NULL) {
-      queue_destroy(q);
-      goto done;
-    }
-    protocol_session_set_max_alloc(&context->session, config->max_alloc);
-    protocol_session_set_io_timeout(&context->session,
-                                    protocol_server_io_timeout_sec(config->timeout));
-    atomic_store(&context->session.total_allocated_bytes,
-                 atomic_load(&session.total_allocated_bytes));
-    pipeline_context_receiver_set_queue_byte_limit(context, RECEIVER_QUEUE_MAX_BYTES);
-    thrd_t receiver = {0};
-    thrd_t writer = {0};
-    bool receiver_created = thrd_create(&receiver, receive_thread, context) == thrd_success;
-    bool writer_created = false;
-    if (receiver_created)
-      writer_created = thrd_create(&writer, write_thread, context) == thrd_success;
-    if (!receiver_created || !writer_created) {
-      log_perror("Error creating Threads");
-      if (receiver_created) {
-        mtx_lock(&context->mutex);
-        atomic_store(&context->cancelled, true);
-        cnd_broadcast(&context->condition_not_full);
-        cnd_broadcast(&context->condition_not_empty);
-        mtx_unlock(&context->mutex);
-        /* Unblock a worker parked in socket I/O without closing the fd (the
-         * child owns the single close).  shutdown() only affects sockets; for
-         * the --stdio pipe the receiver's per-message poll timeout still
-         * bounds the join, so do nothing there rather than close a descriptor
-         * another thread may still be using. */
-        struct stat fd_stat;
-        if (fstat(file_descriptor, &fd_stat) == 0 && S_ISSOCK(fd_stat.st_mode))
-          shutdown(file_descriptor, SHUT_RDWR);
-        thrd_join(receiver, NULL);
-      }
-      if (writer_created)
-        thrd_join(writer, NULL);
-      goto done;
-    }
-    int receiver_result;
-    int writer_result;
-    thrd_join(receiver, &receiver_result);
-    thrd_join(writer, &writer_result);
-    bool transfer_ok = receiver_result == thrd_success && writer_result == thrd_success;
-    if (transfer_ok && !config->dry_run) {
-      /* Commit-style (late) deletion: receive_thread handed the keep-set
-         manifest here instead of deleting while write_thread might still be
-         draining, so by now every file is on disk and the whole transfer is
-         known to have succeeded.  Remove the extras before publishing a
-         --delay-updates run; the walker skips the staging directory.  A
-         server-contacting --dry-run deletes nothing (no manifest is sent). */
-      if (context->deferred_manifest) {
-        size_t deleted = 0;
-        DeletePathObserver observer = config->report_deletes ? receiver_record_deleted_path : NULL;
-        DeleteCommitResult deletion = manifest_delete_all_observed(
-            config, context->deferred_manifest, &deleted, observer, (void*)context->deleted_paths);
-        context->stats.deleted_files += deleted;
-        if (deletion == DELETE_COMMIT_ERROR) {
-          transfer_ok = false;
-        } else if (deletion == DELETE_COMMIT_LIMIT_REACHED) {
-          /* The transfer still succeeds; the terminal frame reports the capped
-             deletion so the sender exits 25 like rsync. */
-          context->delete_limit_reached = true;
-        }
-        delete_manifest_free(context->deferred_manifest);
-        context->deferred_manifest = NULL;
-      }
-      /* --delete-delay: receive_thread snapshotted each plan's extras as it
-         arrived; with the disk writer drained, commit the deferred removals.
-         --delete-during already applied its plans on the receive thread. */
-      if (context->deferred_plans) {
-        /* Defence in depth (the enclosing block already excludes dry-run): a
-           -n run never commits a deletion. */
-        if (config->report_deletes)
-          delete_plan_session_set_delete_observer(
-              context->deferred_plans, receiver_record_deleted_path, (void*)context->deleted_paths);
-        DeleteCommitResult deletion =
-            config->dry_run ? DELETE_COMMIT_OK
-                            : delete_plan_session_commit(context->deferred_plans, config);
-        context->stats.deleted_files += delete_plan_session_deleted(context->deferred_plans);
-        if (deletion == DELETE_COMMIT_ERROR) {
-          transfer_ok = false;
-        } else if (deletion == DELETE_COMMIT_LIMIT_REACHED) {
-          context->delete_limit_reached = true;
-        }
-        delete_plan_session_destroy(context->deferred_plans);
-        context->deferred_plans = NULL;
-      }
-    }
-    if (transfer_ok && !config->dry_run) {
-      /* --delay-updates: receive_thread has finished the whole protocol stream
-         (including manifest/delete handling) and write_thread has drained its
-         queue, so every staged file is complete.  Publish atomically before the
-         success/outcome frame so a --remove-source-files sender only learns of
-         files that were actually installed. */
-      if (config->delay_updates && config->delay_context &&
-          !delay_updates_publish(config->delay_context, config)) {
-        transfer_ok = false;
-      }
-      /* P7 Wave D: all writers have joined and the late deletion (and
-         --delay-updates publication) has committed above, so it is finally safe
-         to stamp directory times; a directory's mtime must not be clobbered by
-         its children or by an extra removal. */
-      if (transfer_ok)
-        dir_metadata_list_apply(&context->dir_times, config->receive_root_directory, config);
-    }
-    if (transfer_ok) {
-      Status final_status = context->delete_limit_reached ? STATUS_DELETE_LIMIT : STATUS_OK;
-      /* Emit the optional wire-stats record first (protocol 2.25.0), then the
-         success/outcome frame, exactly like the single-threaded receiver. */
-      if (!receiver_send_stats_frame(file_descriptor, config, &context->stats,
-                                     context->would_delete, context->deleted_paths) ||
-          !receiver_send_final_success(file_descriptor, config, &context->outcomes, final_status))
-        transfer_ok = false;
-    } else {
-      send_error_detail(file_descriptor, "transfer failed on receiver");
-    }
-    if (!transfer_ok)
-      log_message(LOG_LEVEL_ERROR, "Transfer failed");
-  } else {
-    if (receiver_receive_files(config, file_descriptor) != 0)
-      log_message(LOG_LEVEL_ERROR, "Transfer failed");
+  return true;
+}
+
+/* Phase 4a -- transfer via the multithreaded receiver.  Spawns the receive/write
+ * thread pair, joins them, then commits the late deletion, --delay-updates
+ * publication and directory times before emitting the terminal stats/success
+ * frame.  On any failure the helper just returns; the caller's `done` epilogue
+ * releases the pipeline context (which owns the config and queue) exactly as the
+ * former inline code did. */
+static void server_run_mt_receiver(ServerSession* state) {
+  Config* config = state->config;
+  Queue* q = queue_create(100, file_destroy);
+  if (q == NULL)
+    return;
+  state->context = pipeline_context_receiver_create(config, q, state->fd, state->ssl);
+  if (state->context == NULL) {
+    queue_destroy(q);
+    return;
   }
+  protocol_session_set_max_alloc(&state->context->session, config->max_alloc);
+  protocol_session_set_io_timeout(&state->context->session,
+                                  protocol_server_io_timeout_sec(config->timeout));
+  atomic_store(&state->context->session.total_allocated_bytes,
+               atomic_load(&state->session.total_allocated_bytes));
+  pipeline_context_receiver_set_queue_byte_limit(state->context, RECEIVER_QUEUE_MAX_BYTES);
+  thrd_t receiver = {0};
+  thrd_t writer = {0};
+  bool receiver_created = thrd_create(&receiver, receive_thread, state->context) == thrd_success;
+  bool writer_created = false;
+  if (receiver_created)
+    writer_created = thrd_create(&writer, write_thread, state->context) == thrd_success;
+  if (!receiver_created || !writer_created) {
+    log_perror("Error creating Threads");
+    if (receiver_created) {
+      mtx_lock(&state->context->mutex);
+      atomic_store(&state->context->cancelled, true);
+      cnd_broadcast(&state->context->condition_not_full);
+      cnd_broadcast(&state->context->condition_not_empty);
+      mtx_unlock(&state->context->mutex);
+      /* Unblock a worker parked in socket I/O without closing the fd (the
+       * child owns the single close).  shutdown() only affects sockets; for
+       * the --stdio pipe the receiver's per-message poll timeout still
+       * bounds the join, so do nothing there rather than close a descriptor
+       * another thread may still be using. */
+      struct stat fd_stat;
+      if (fstat(state->fd, &fd_stat) == 0 && S_ISSOCK(fd_stat.st_mode))
+        shutdown(state->fd, SHUT_RDWR);
+      thrd_join(receiver, NULL);
+    }
+    if (writer_created)
+      thrd_join(writer, NULL);
+    return;
+  }
+  int receiver_result;
+  int writer_result;
+  thrd_join(receiver, &receiver_result);
+  thrd_join(writer, &writer_result);
+  bool transfer_ok = receiver_result == thrd_success && writer_result == thrd_success;
+  PipelineContextReceiver* context = state->context;
+  if (transfer_ok && !config->dry_run) {
+    /* Commit-style (late) deletion: receive_thread handed the keep-set
+       manifest here instead of deleting while write_thread might still be
+       draining, so by now every file is on disk and the whole transfer is
+       known to have succeeded.  Remove the extras before publishing a
+       --delay-updates run; the walker skips the staging directory.  A
+       server-contacting --dry-run deletes nothing (no manifest is sent). */
+    if (context->deferred_manifest) {
+      size_t deleted = 0;
+      DeletePathObserver observer = config->report_deletes ? receiver_record_deleted_path : NULL;
+      DeleteCommitResult deletion = manifest_delete_all_observed(
+          config, context->deferred_manifest, &deleted, observer, (void*)context->deleted_paths);
+      context->stats.deleted_files += deleted;
+      if (deletion == DELETE_COMMIT_ERROR) {
+        transfer_ok = false;
+      } else if (deletion == DELETE_COMMIT_LIMIT_REACHED) {
+        /* The transfer still succeeds; the terminal frame reports the capped
+           deletion so the sender exits 25 like rsync. */
+        context->delete_limit_reached = true;
+      }
+      delete_manifest_free(context->deferred_manifest);
+      context->deferred_manifest = NULL;
+    }
+    /* --delete-delay: receive_thread snapshotted each plan's extras as it
+       arrived; with the disk writer drained, commit the deferred removals.
+       --delete-during already applied its plans on the receive thread. */
+    if (context->deferred_plans) {
+      /* Defence in depth (the enclosing block already excludes dry-run): a
+         -n run never commits a deletion. */
+      if (config->report_deletes)
+        delete_plan_session_set_delete_observer(
+            context->deferred_plans, receiver_record_deleted_path, (void*)context->deleted_paths);
+      DeleteCommitResult deletion =
+          config->dry_run ? DELETE_COMMIT_OK
+                          : delete_plan_session_commit(context->deferred_plans, config);
+      context->stats.deleted_files += delete_plan_session_deleted(context->deferred_plans);
+      if (deletion == DELETE_COMMIT_ERROR) {
+        transfer_ok = false;
+      } else if (deletion == DELETE_COMMIT_LIMIT_REACHED) {
+        context->delete_limit_reached = true;
+      }
+      delete_plan_session_destroy(context->deferred_plans);
+      context->deferred_plans = NULL;
+    }
+  }
+  if (transfer_ok && !config->dry_run) {
+    /* --delay-updates: receive_thread has finished the whole protocol stream
+       (including manifest/delete handling) and write_thread has drained its
+       queue, so every staged file is complete.  Publish atomically before the
+       success/outcome frame so a --remove-source-files sender only learns of
+       files that were actually installed. */
+    if (config->delay_updates && config->delay_context &&
+        !delay_updates_publish(config->delay_context, config)) {
+      transfer_ok = false;
+    }
+    /* P7 Wave D: all writers have joined and the late deletion (and
+       --delay-updates publication) has committed above, so it is finally safe
+       to stamp directory times; a directory's mtime must not be clobbered by
+       its children or by an extra removal. */
+    if (transfer_ok)
+      dir_metadata_list_apply(&context->dir_times, config->receive_root_directory, config);
+  }
+  if (transfer_ok) {
+    Status final_status = context->delete_limit_reached ? STATUS_DELETE_LIMIT : STATUS_OK;
+    /* Emit the optional wire-stats record first (protocol 2.25.0), then the
+       success/outcome frame, exactly like the single-threaded receiver. */
+    if (!receiver_send_stats_frame(state->fd, config, &context->stats, context->would_delete,
+                                   context->deleted_paths) ||
+        !receiver_send_final_success(state->fd, config, &context->outcomes, final_status))
+      transfer_ok = false;
+  } else {
+    send_error_detail(state->fd, "transfer failed on receiver");
+  }
+  if (!transfer_ok)
+    log_message(LOG_LEVEL_ERROR, "Transfer failed");
+}
+
+/* Phase 4b -- transfer via the single-threaded receiver.  Failure is logged
+ * exactly as before; the caller's `done` epilogue then releases the config. */
+static void server_run_st_receiver(ServerSession* state) {
+  if (receiver_receive_files(state->config, state->fd) != 0)
+    log_message(LOG_LEVEL_ERROR, "Transfer failed");
+}
+
+/* Phase 4 dispatch -- choose the receiver implementation the config asks for.
+ * Both helpers own their success/failure logging; the caller falls through to
+ * the shared `done` epilogue either way. */
+static void server_run_transfer(ServerSession* state) {
+  if (state->config->use_multithreading)
+    server_run_mt_receiver(state);
+  else
+    server_run_st_receiver(state);
+}
+
+void handler(int file_descriptor) {
+  /* Single per-connection state; every phase helper below advances it and
+   * returns false on a logged failure.  All teardown state starts empty so the
+   * single `done` epilogue is safe to reach from any error path (including
+   * before the config frame arrives). */
+  ServerSession state;
+  state.fd = file_descriptor;
+  state.ssl = io_get_ssl();
+  protocol_session_init(&state.session, file_descriptor, file_descriptor);
+  protocol_session_set_ssl(&state.session, state.ssl);
+  protocol_session_bind(&state.session);
+  state.gate_ctx.ssl = state.ssl;
+  state.gate_ctx.fd = file_descriptor;
+  state.gate_ctx.super_mode_override = -1;
+  state.gate_ctx.has_peer_ip = false;
+  state.gate_ctx.peer_ip[0] = '\0';
+  state.gate_ctx.is_local = false;
+  state.config = NULL;
+  state.context = NULL;
+  state.joined_destination = NULL;
+  state.charset_ready = false;
+
+  if (!server_accept_config(&state))
+    goto done;
+  if (!server_apply_security_gates(&state))
+    goto done;
+  if (!server_prepare_session(&state))
+    goto done;
+  server_run_transfer(&state);
 
 done:
   /* Single cleanup epilogue: every error path jumps here, so the iconv
@@ -1029,22 +1112,22 @@ done:
    * connection fd is deliberately NOT closed here -- the child functions own
    * its single close (plain_child_fn / tls_child_fn), and the --stdio call
    * site must leave stdin/stdout open. */
-  if (charset_ready)
+  if (state.charset_ready)
     charset_wire_free();
   /* The delay-updates staging tree is released by config_delete (which the
      branch below always reaches), so it is cleaned exactly once. */
   identity_clear_active();
   protocol_session_unbind();
-  if (context != NULL) {
+  if (state.context != NULL) {
     /* context owns both the config and the queue it was created with. */
-    pipeline_context_receiver_destroy(context);
-    context = NULL;
-    config = NULL;
+    pipeline_context_receiver_destroy(state.context);
+    state.context = NULL;
+    state.config = NULL;
   } else {
-    config_delete(config);
-    config = NULL;
+    config_delete(state.config);
+    state.config = NULL;
   }
-  free(joined_destination);
+  free(state.joined_destination);
 }
 
 #ifndef FASTSYNC_SERVER_AS_LIB

src/shared/config.c

@@ -20,9 +20,9 @@
 
 static void config_set_defaults(Config* config) {
   config->scanner_threads = 0;
-  config->metadata_explicitly_disabled = false;
-  config->preserve_perms_explicit_off = false;
-  config->preserve_times_explicit_off = false;
+  config->cli.preserve_perms_explicit_off = false;
+  config->cli.preserve_times_explicit_off = false;
+  config->cli.metadata_explicitly_disabled = false;
   config->show_progress = false;
   config->compression_threads = 0;
   config->ssh_port = 22;
@@ -44,8 +44,8 @@ static void config_set_defaults(Config* config) {
   config->tls_ca = NULL;
   config->server_host = str_dup("127.0.0.1");
   config->server_port = 8080;
-  config->server_port_set = false;
-  config->server_host_set = false;
+  config->cli.server_port_set = false;
+  config->cli.server_host_set = false;
   /* rsync defaults: --timeout=0 (I/O timeouts disabled) and --contimeout=60.
    * A value of 0 disables the client's own deadline on both the socket layer
    * (tcp_set_timeouts) and the protocol layer
@@ -68,10 +68,10 @@ static void config_set_defaults(Config* config) {
   config->human_readable = false;
   config->ignore_errors = false;
   config->ignore_missing_args = false;
-  config->checksum_transfer_algo = CHECKSUM_ALGO_DEFAULT;
-  config->cli_exit_code = 0;
-  config->compression_level_set = false;
-  config->checksum_choice_set = false;
+  config->cli.checksum_transfer_algo = CHECKSUM_ALGO_DEFAULT;
+  config->cli.cli_exit_code = 0;
+  config->cli.compression_level_set = false;
+  config->cli.checksum_choice_set = false;
   config->filters = NULL;
   config->files_from = NULL;
   config->files_from_set = NULL;
@@ -85,7 +85,6 @@ static void config_set_defaults(Config* config) {
   config->rsh_command = NULL;
   config->blocking_io = false;
   config->outbuf = OUTBUF_BLOCK;
-  config->old_args = false;
   config->remote_options = NULL;
   config->remote_option_count = 0;
   config->address = NULL;
@@ -101,7 +100,7 @@ static void config_set_defaults(Config* config) {
   config->trust_sender = false;
   config->stop_after_mins = 0;
   config->stop_at = 0;
-  config->stop_at_set = false;
+  config->cli.stop_at_set = false;
   config->write_batch = NULL;
   config->only_write_batch = NULL;
   config->read_batch = NULL;
@@ -342,7 +341,8 @@ bool config_derived_use_metadata(const Config* config) {
       config->chown_uid_set || config->chown_gid_set || config->usermap_count > 0 ||
       config->groupmap_count > 0 || config->update)
     return true;
-  return (config->use_incremental || config->use_delta) && !config->metadata_explicitly_disabled;
+  return (config->use_incremental || config->use_delta) &&
+         !config->cli.metadata_explicitly_disabled;
 }
 
 bool config_has_basis(const Config* config) {

src/shared/config.h

@@ -342,22 +342,60 @@ typedef enum SuperMode { SUPER_MODE_AUTO = 0, SUPER_MODE_ON = 1, SUPER_MODE_OFF
   CONFIG_WIRE_CODEC_FIELDS(X)                                                                      \
   CONFIG_WIRE_PROTECT_FIELDS(X)
 
+/* Client-only, CLI-parse bookkeeping (never serialized).  These members exist
+ * only so the client command-line parser can record HOW an option was
+ * specified (explicitly set, explicitly negated, or a parser-requested exit
+ * code); no other module and no wire peer ever needs them.  Grouping them in
+ * one nested member keeps the public Config free of client-CLI-only state. */
+typedef struct {
+  /* Set when the user explicitly turned an attribute off with --no-perms /
+   * --no-times (long or short form).  --incremental/--delta historically
+   * auto-enabled mode and mtime preservation; these flags let
+   * cli_finalize_config restore that behavior while still honoring the
+   * explicit per-attribute negation.  A later -p/-t re-enables the attribute
+   * directly, so the flag only prevents the incremental/delta implication,
+   * never a POSITIVE request. */
+  bool preserve_perms_explicit_off;
+  bool preserve_times_explicit_off;
+  /* Set by --no-preserve, the explicit opt-out of the whole preservation
+   * bundle, so the --incremental/--delta auto-preserve implication stays off. */
+  bool metadata_explicitly_disabled;
+  /* True when --server-port/--port was explicitly given.  --dry-run uses it to
+   * decide whether a real server handshake was requested, so a plain local
+   * destination (no explicit port) keeps the existing client-side dry-run
+   * behavior instead of dialing the default 127.0.0.1:8080. */
+  bool server_port_set;
+  /* True when --server-host was explicitly given, and distinct from the
+   * "127.0.0.1" default: --dry-run uses it to route an explicit remote target
+   * to the server so it reports receiver state exactly like a real run,
+   * instead of silently running the client-side manifest. */
+  bool server_host_set;
+  /* Codec-negotiation CLI state.  The effective pre-transfer checksum is
+   * Config->checksum_algo (serialized); checksum_transfer_algo is the rsync
+   * "transfer" half of a two-name --checksum-choice form (validated and used
+   * only to mirror rsync's whole-file forcing, since FastSync's per-block
+   * strong hash is fixed).  cli_exit_code carries a parser-requested process
+   * exit status (rsync uses 4 for an unsupported checksum/compress algorithm)
+   * so main() can mirror it. */
+  int checksum_transfer_algo;
+  int cli_exit_code;
+  /* "The user explicitly chose" bits.  They let the per-codec default level /
+   * checksum list be applied only when the corresponding rsync option was
+   * omitted (an explicit --compress-level / --checksum-choice always wins). */
+  bool compression_level_set;
+  bool checksum_choice_set;
+  /* True when --stop-at was given. */
+  bool stop_at_set;
+} ConfigCliParse;
+
 typedef struct Config {
   /* -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 metadata_explicitly_disabled;
-  /* CLIENT-ONLY (never serialized; not in CONFIG_WIRE_FIELDS).  Set when the
-   * user explicitly turned an attribute off with --no-perms / --no-times (long
-   * or short form).  --incremental/--delta historically auto-enabled mode and
-   * mtime preservation; these flags let cli_finalize_config restore that
-   * behavior while still honoring the explicit per-attribute negation.  A
-   * later -p/-t re-enables the attribute directly, so the flag only prevents
-   * the incremental/delta implication, never a POSITIVE request. */
-  bool preserve_perms_explicit_off;
-  bool preserve_times_explicit_off;
+  /* Client-only CLI-parse bookkeeping (never serialized).  See ConfigCliParse. */
+  ConfigCliParse cli;
   bool show_progress;
   int compression_threads;
   int ssh_port;
@@ -378,18 +416,6 @@ typedef struct Config {
   bool use_tls;
   char* server_host;
   int server_port;
-  /* True when --server-port/--port was explicitly given.  CLIENT-ONLY (never
-   * serialized): --dry-run uses it to decide whether a real server handshake
-   * was requested, so a plain local destination (no explicit port) keeps the
-   * existing client-side dry-run behavior instead of dialing the default
-   * 127.0.0.1:8080. */
-  bool server_port_set;
-  /* True when --server-host was explicitly given.  CLIENT-ONLY (never
-   * serialized), and distinct from the "127.0.0.1" default: --dry-run uses it
-   * to route an explicit remote target to the server so it reports receiver
-   * state exactly like a real run, instead of silently running the client-side
-   * manifest. */
-  bool server_host_set;
   char* tls_cert;
   char* tls_key;
   char* tls_ca;
@@ -435,22 +461,6 @@ typedef struct Config {
    * enters the keep-set.  Implied by --delete-missing-args. */
   bool ignore_missing_args;
 
-  /* Codec-negotiation CLI state (all client-only, never serialized).  The
-   * effective pre-transfer checksum is Config->checksum_algo (serialized);
-   * checksum_transfer_algo is the rsync "transfer" half of a two-name
-   * --checksum-choice form (validated and used only to mirror rsync's
-   * whole-file forcing, since FastSync's per-block strong hash is fixed).
-   * cli_exit_code carries a parser-requested process exit status (rsync uses 4
-   * for an unsupported checksum/compress algorithm) so main() can mirror it. */
-  int checksum_transfer_algo;
-  int cli_exit_code;
-  /* Client-only "the user explicitly chose" bits.  They let the per-codec
-   * default level / checksum list be applied only when the corresponding
-   * rsync option was omitted (an explicit --compress-level / --checksum-choice
-   * always wins).  Never serialized. */
-  bool compression_level_set;
-  bool checksum_choice_set;
-
   // Issue #129: Advanced file selection. These fields are CLIENT-ONLY: they are
   // never serialized to the wire (the receiver must not learn them).
   ArrayList* filters;   /* --filter=RULE rule strings, in order */
@@ -486,7 +496,6 @@ typedef struct Config {
   /* --outbuf mode (OutbufMode): stdout/stderr buffering.  Client-only launch
    * concern: NEVER crosses the wire. */
   int outbuf;
-  bool old_args;
   /* --remote-option=OPT (Phase 5, long form only): one or more extra command-line
    * options to append to the REMOTE server invocation over SSH.  CLIENT-ONLY:
    * they are composed into the remote command line by ssh_build_remote_command()
@@ -556,7 +565,6 @@ typedef struct Config {
    * process and are NEVER serialized into the config frame. */
   int stop_after_mins; /* --stop-after=MINS minutes; 0 when unset */
   time_t stop_at;      /* --stop-at=... absolute wall-clock deadline */
-  bool stop_at_set;    /* true when --stop-at was given */
 
   /* Client-only residual-batch paths.  A residual batch is a self-contained
    * single-file record of the whole source tree (full file images using the

src/shared/delete.c

@@ -0,0 +1,656 @@
+#include "delete.h"
+
+#include "delay_updates.h"
+#include "filter.h"
+#include "log.h"
+#include "utils.h"
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+/* Build the keep-set index from the exact manifest entries only.  A lookup of
+   `rel` succeeds iff `rel` is a kept entry, a kept directory, or an ancestor
+   directory of kept content (the old is_dir_in_manifest predicate); the sorted
+   view answers "is an ancestor of kept content" without materializing any
+   per-component prefix copy, so the index is O(manifest size) memory. */
+static bool build_keep_index(const ArrayList* manifest, PathIndex* index) {
+  if (!manifest || manifest->size <= 0)
+    return path_index_build(index, NULL, 0);
+  return path_index_build(index, (const char* const*)manifest->items, (size_t)manifest->size);
+}
+
+static bool keep_is_dir(const PathIndex* index, const char* rel_path) {
+  return path_index_contains(index, rel_path) || path_index_has_descendant(index, rel_path);
+}
+
+static bool keep_is_file(const PathIndex* index, const char* rel_path) {
+  return path_index_contains(index, rel_path);
+}
+
+/* True when child_rel is, or lies below, a protected entry.  A prefix "a"
+   therefore protects "a" and "a/b/c" but not "ab".  Entries with top_level_only
+   set only protect DIRECT children of the receive root (at_root); nested
+   directories that share such a name stay ordinary destination content. */
+bool path_under_skip_prefix(const char* child_rel, bool at_root, const DeleteSkipEntry* skips,
+                            int skip_count) {
+  for (int i = 0; i < skip_count; i++) {
+    if (skips[i].top_level_only && !at_root)
+      continue;
+    size_t prefix_len = strlen(skips[i].prefix);
+    if (strncmp(child_rel, skips[i].prefix, prefix_len) == 0 &&
+        (child_rel[prefix_len] == '\0' || child_rel[prefix_len] == '/'))
+      return true;
+  }
+  return false;
+}
+
+/* Per-run deletion budget and tallies.  `max_delete` is the cap on the number
+   of entries the walker may remove (SIZE_MAX = unlimited); once it is reached
+   the remaining extras are counted in `skipped` and left in place, matching
+   rsync's partial --max-delete behavior. */
+typedef struct {
+  size_t max_delete;
+  size_t deleted;
+  size_t skipped;
+  bool limit_hit;
+} DeleteBudget;
+
+/* True when direct children of the directory named by `rel` may be removed.
+   With no synchronization info (dirs == NULL) the whole tree is deletable; when
+   a dirs index is supplied only its exact entries are (the receive root is the
+   "." sentinel). */
+static bool is_synced_dir(const PathIndex* dirs, const char* rel) {
+  if (!dirs)
+    return true;
+  return path_index_contains(dirs, rel[0] == '\0' ? "." : rel);
+}
+
+/* Unsigned byte-wise string compare, matching rsync's u_strcmp (a signed
+   strcmp would order bytes >= 0x80 differently). */
+static int delete_name_cmp(const char* a, const char* b) {
+  const unsigned char* pa = (const unsigned char*)a;
+  const unsigned char* pb = (const unsigned char*)b;
+  while (*pa != '\0' && *pa == *pb) {
+    pa++;
+    pb++;
+  }
+  return (int)*pa - (int)*pb;
+}
+
+bool delete_dir_entries_collect(int dirfd, DeleteDirEntry** out, size_t* count,
+                                bool* operation_ok) {
+  *out = NULL;
+  *count = 0;
+  if (operation_ok)
+    *operation_ok = true;
+  int scanfd = openat(dirfd, ".", O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
+  if (scanfd < 0)
+    return false;
+  DIR* dir = fdopendir(scanfd);
+  if (!dir) {
+    close(scanfd);
+    return false;
+  }
+  DeleteDirEntry* entries = NULL;
+  size_t used = 0;
+  size_t capacity = 0;
+  bool ok = true;
+  const struct dirent* entry;
+  while ((entry = readdir(dir)) != NULL) {
+    if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
+      continue;
+    struct stat st;
+    if (fstatat(dirfd, entry->d_name, &st, AT_SYMLINK_NOFOLLOW) != 0) {
+      if (errno != ENOENT && operation_ok)
+        *operation_ok = false;
+      continue;
+    }
+    if (used == capacity) {
+      size_t next = capacity == 0 ? 16 : capacity * 2;
+      DeleteDirEntry* grown = realloc(entries, next * sizeof(*grown));
+      if (!grown) {
+        ok = false;
+        break;
+      }
+      entries = grown;
+      capacity = next;
+    }
+    entries[used].name = str_dup(entry->d_name);
+    if (!entries[used].name) {
+      ok = false;
+      break;
+    }
+    entries[used].is_dir = S_ISDIR(st.st_mode);
+    used++;
+  }
+  closedir(dir);
+  if (!ok) {
+    delete_dir_entries_free(entries, used);
+    return false;
+  }
+  *out = entries;
+  *count = used;
+  return true;
+}
+
+void delete_dir_entries_free(DeleteDirEntry* entries, size_t count) {
+  if (!entries)
+    return;
+  for (size_t i = 0; i < count; i++)
+    free(entries[i].name);
+  free(entries);
+}
+
+/* rsync's extraneous-entry order: subdirectories before files, each group in
+   descending name order. */
+int delete_dir_entry_cmp_desc(const void* a, const void* b) {
+  const DeleteDirEntry* ea = a;
+  const DeleteDirEntry* eb = b;
+  if (ea->is_dir != eb->is_dir)
+    return ea->is_dir ? -1 : 1;
+  return -delete_name_cmp(ea->name, eb->name);
+}
+
+/* rsync's kept-subdirectory order: plain ascending name. */
+int delete_dir_entry_cmp_asc(const void* a, const void* b) {
+  const DeleteDirEntry* ea = a;
+  const DeleteDirEntry* eb = b;
+  return delete_name_cmp(ea->name, eb->name);
+}
+
+/* How the shared classification/descent walk disposes of an extra it has
+   identified.  LIST records the destination-relative path without touching disk
+   (the -n/--dry-run would-delete enumeration); DELETE unlinks/rmdirs it, charges
+   the shared --max-delete budget and notifies the observer.  Both modes classify
+   and traverse identically, so the dry-run enumeration and the real deletion
+   cannot drift. */
+typedef enum { DELETE_WALK_MODE_DELETE, DELETE_WALK_MODE_LIST } DeleteWalkMode;
+
+typedef struct {
+  DeleteWalkMode mode;
+  DeleteBudget* budget;        /* DELETE mode */
+  ArrayList* out;              /* LIST mode: receives strdup'd relative paths */
+  size_t* recorded;            /* LIST mode */
+  DeletePathObserver observer; /* DELETE mode */
+  void* observer_context;      /* DELETE mode */
+} DeleteWalkState;
+
+/* Remove the extras directly inside the directory open on `dirfd` (DELETE mode)
+   or record the paths that WOULD be removed (LIST mode), recursing into every
+   child directory so kept content below a synchronized prefix is reached.
+   `all_removed` reports whether every child entry was removed (so the caller may
+   rmdir this directory).  A child directory is never removed when it is itself a
+   synchronized directory or holds kept content; with a dirs index supplied,
+   direct children of a non-synchronized directory are never extras at all (they
+   are left in place but still descended into).  Symlinks are unlinked like any
+   other non-directory extra (never followed).
+
+   Entries are processed in rsync's order (extraneous subdirectories in
+   descending name order, then extraneous files, then kept subdirectories in
+   ascending order) rather than readdir() order, so `--max-delete` leaves the
+   same survivors and the `--info=del`/dry-run line order matches rsync. */
+static bool delete_walk_fd(int dirfd, const char* rel_path, const PathIndex* keep,
+                           const PathIndex* dirs, DeleteWalkState* state,
+                           const DeleteSkipEntry* skips, int skip_count,
+                           const FilterRuleList* protect_rules, bool parent_deletable,
+                           bool* all_removed) {
+  DeleteDirEntry* entries = NULL;
+  size_t count = 0;
+  bool collect_ok = true;
+  if (!delete_dir_entries_collect(dirfd, &entries, &count, &collect_ok))
+    return false;
+  bool operation_ok = collect_ok;
+  bool local_survives = false;
+  bool* shielded = calloc(count ? count : 1, sizeof(bool));
+  bool* is_extra = calloc(count ? count : 1, sizeof(bool));
+  if (!shielded || !is_extra) {
+    free(shielded);
+    free(is_extra);
+    delete_dir_entries_free(entries, count);
+    return false;
+  }
+  /* A directory is deletable when it or ANY ancestor is synchronized; the
+     `parent_deletable` flag carries that down the recursion so dest-only
+     directories below a synchronized root are removed wholesale. */
+  bool deletable = parent_deletable || is_synced_dir(dirs, rel_path);
+  bool at_root = rel_path[0] == '\0';
+
+  /* Reproduce rsync's traversal order: extraneous subdirectories in descending
+     name order, then extraneous files in descending name order, and kept
+     subdirectories only afterwards (ascending).  Sorting up front also fixes the
+     identity of the survivors under a partial --max-delete. */
+  if (count > 1)
+    qsort(entries, count, sizeof(*entries), delete_dir_entry_cmp_desc);
+  size_t dir_count = 0;
+  while (dir_count < count && entries[dir_count].is_dir)
+    dir_count++;
+
+  /* Classify every entry up front (the verdict does not depend on processing
+     order) so the ordered passes below can act on it. */
+  for (size_t i = 0; i < count; i++) {
+    char* child_rel = path_cat((char*)rel_path, entries[i].name);
+    if (!child_rel) {
+      operation_ok = false;
+      continue;
+    }
+    /* A --delay-updates run keeps its staging directory as a direct child of
+       the receive root, and basis-dir snapshots live below it too.  Their
+       contents are not manifest entries, so descending into them would delete
+       every staged / basis file as an "extra".  Only the staging name (a
+       top-level-only prefix) and the basis prefixes are protected: a nested
+       destination directory that happens to be called .fastsync-stage is
+       ordinary content. */
+    if (path_under_skip_prefix(child_rel, at_root, skips, skip_count)) {
+      shielded[i] = true;
+      local_survives = true;
+    } else if (protect_rules &&
+               filter_rules_apply_side(protect_rules, child_rel, entries[i].name, entries[i].is_dir,
+                                       FILTER_SIDE_RECEIVER) == FILTER_ACTION_PROTECT) {
+      /* A first-match protect rule shields the extra; for a directory the whole
+         subtree is shielded (rsync prunes an excluded directory), so do not
+         descend. */
+      shielded[i] = true;
+      local_survives = true;
+    } else if (entries[i].is_dir) {
+      bool child_synced = dirs && path_index_contains(dirs, child_rel);
+      is_extra[i] = deletable && !child_synced && !keep_is_dir(keep, child_rel);
+      if (!is_extra[i])
+        local_survives = true;
+    } else {
+      is_extra[i] = deletable && !keep_is_file(keep, child_rel);
+      if (!is_extra[i])
+        local_survives = true;
+    }
+    free(child_rel);
+  }
+
+  /* Pass 1: extraneous subdirectories, descending. */
+  for (size_t i = 0; i < dir_count; i++) {
+    if (!is_extra[i])
+      continue;
+    char* child_rel = path_cat((char*)rel_path, entries[i].name);
+    if (!child_rel) {
+      operation_ok = false;
+      continue;
+    }
+    int childfd = openat(dirfd, entries[i].name, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
+    bool child_all_removed = false;
+    if (childfd >= 0) {
+      if (!delete_walk_fd(childfd, child_rel, keep, dirs, state, skips, skip_count, protect_rules,
+                          deletable, &child_all_removed))
+        operation_ok = false;
+      close(childfd);
+    } else if (errno != ENOENT) {
+      operation_ok = false;
+    }
+    if (child_all_removed && deletable) {
+      if (state->mode == DELETE_WALK_MODE_LIST) {
+        /* Record the directory with rsync's trailing slash. */
+        size_t len = strlen(child_rel);
+        char* copy = malloc(len + 2);
+        if (!copy) {
+          operation_ok = false;
+        } else {
+          memcpy(copy, child_rel, len);
+          copy[len] = '/';
+          copy[len + 1] = '\0';
+          if (!array_list_add(state->out, copy)) {
+            free(copy);
+            operation_ok = false;
+          } else {
+            (*state->recorded)++;
+          }
+        }
+      } else if (state->budget->deleted >= state->budget->max_delete) {
+        state->budget->limit_hit = true;
+        state->budget->skipped++;
+        local_survives = true;
+      } else if (unlinkat(dirfd, entries[i].name, AT_REMOVEDIR) != 0) {
+        /* ENOENT: already gone (fine).  ENOTEMPTY/EEXIST: the directory still
+           holds entries the walker leaves in place (a protected excluded
+           prefix, a kept file the manifest protects, a symlink); rsync leaves
+           such a directory behind, so this is not an error.  Only genuine I/O
+           failures abort the deletion. */
+        if (errno != ENOENT && errno != ENOTEMPTY && errno != EEXIST)
+          operation_ok = false;
+        local_survives = true;
+      } else {
+        state->budget->deleted++;
+        /* rsync reports a removed directory with a trailing slash. */
+        if (state->observer) {
+          size_t len = strlen(child_rel);
+          char* with_slash = malloc(len + 2);
+          if (with_slash) {
+            memcpy(with_slash, child_rel, len);
+            with_slash[len] = '/';
+            with_slash[len + 1] = '\0';
+            state->observer(state->observer_context, with_slash);
+            free(with_slash);
+          } else {
+            state->observer(state->observer_context, child_rel);
+          }
+        }
+      }
+    } else {
+      local_survives = true;
+    }
+    free(child_rel);
+  }
+
+  /* Pass 2: extraneous files, descending. */
+  for (size_t i = dir_count; i < count; i++) {
+    if (!is_extra[i])
+      continue;
+    if (state->mode == DELETE_WALK_MODE_LIST) {
+      char* child_rel = path_cat((char*)rel_path, entries[i].name);
+      if (!child_rel) {
+        operation_ok = false;
+        continue;
+      }
+      char* copy = str_dup(child_rel);
+      if (!copy || !array_list_add(state->out, copy)) {
+        free(copy);
+        operation_ok = false;
+      } else {
+        (*state->recorded)++;
+      }
+      free(child_rel);
+    } else if (state->budget->deleted >= state->budget->max_delete) {
+      state->budget->limit_hit = true;
+      state->budget->skipped++;
+      local_survives = true;
+    } else if (unlinkat(dirfd, entries[i].name, 0) != 0) {
+      if (errno != ENOENT)
+        operation_ok = false;
+      local_survives = true;
+    } else {
+      state->budget->deleted++;
+      char* child_rel = path_cat((char*)rel_path, entries[i].name);
+      if (child_rel) {
+        if (state->observer)
+          state->observer(state->observer_context, child_rel);
+        char* escaped_path = output_escape(child_rel, log_get_8_bit_output());
+        fprintf(stderr, "  Deleted: %s\n", escaped_path ? escaped_path : "<allocation failed>");
+        free(escaped_path);
+      }
+      free(child_rel);
+    }
+  }
+
+  /* Pass 3: kept subdirectories, ascending (rsync descends into these only
+     after the parent's own extras have been handled). */
+  for (size_t i = dir_count; i-- > 0;) {
+    if (is_extra[i] || shielded[i])
+      continue;
+    char* child_rel = path_cat((char*)rel_path, entries[i].name);
+    if (!child_rel) {
+      operation_ok = false;
+      continue;
+    }
+    int childfd = openat(dirfd, entries[i].name, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
+    bool child_all_removed = false;
+    if (childfd >= 0) {
+      if (!delete_walk_fd(childfd, child_rel, keep, dirs, state, skips, skip_count, protect_rules,
+                          deletable, &child_all_removed))
+        operation_ok = false;
+      close(childfd);
+    } else if (errno != ENOENT) {
+      operation_ok = false;
+    }
+    /* A kept/synchronized directory is never removed. */
+    local_survives = true;
+    free(child_rel);
+  }
+
+  free(shielded);
+  free(is_extra);
+  delete_dir_entries_free(entries, count);
+  *all_removed = !local_survives;
+  return operation_ok;
+}
+
+/* Open the receive root following the same authorized-root confinement the
+   walker uses, or dest_root directly when no authorized root is installed. */
+static int open_destination_root(const char* dest_root) {
+  int root_fd = utils_get_authorized_root_fd();
+  if (root_fd >= 0) {
+    if (utils_get_authorized_root_path())
+      return utils_open_authorized_destination(dest_root);
+    if (dest_root == NULL)
+      return dup(root_fd);
+    return -1;
+  }
+  return open(dest_root, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
+}
+
+bool delete_extras_list(const char* dest_root, const ArrayList* manifest,
+                        const ArrayList* synced_dirs, const DeleteSkipEntry* skips, int skip_count,
+                        const FilterRuleList* protect_rules, ArrayList* out, size_t* count_out) {
+  if (count_out)
+    *count_out = 0;
+  if (!manifest || !out)
+    return false;
+  PathIndex keep;
+  if (!build_keep_index(manifest, &keep))
+    return false;
+  PathIndex dirs;
+  bool have_dirs = synced_dirs != NULL;
+  if (have_dirs &&
+      !path_index_build(&dirs, (const char* const*)synced_dirs->items, (size_t)synced_dirs->size)) {
+    path_index_free(&keep);
+    return false;
+  }
+  int rootfd = open_destination_root(dest_root);
+  if (rootfd < 0) {
+    path_index_free(&keep);
+    if (have_dirs)
+      path_index_free(&dirs);
+    return false;
+  }
+  bool all_removed = false;
+  size_t recorded = 0;
+  DeleteWalkState state = {.mode = DELETE_WALK_MODE_LIST,
+                           .budget = NULL,
+                           .out = out,
+                           .recorded = &recorded,
+                           .observer = NULL,
+                           .observer_context = NULL};
+  bool ok = delete_walk_fd(rootfd, "", &keep, have_dirs ? &dirs : NULL, &state, skips, skip_count,
+                           protect_rules, false, &all_removed);
+  if (close(rootfd) != 0)
+    ok = false;
+  path_index_free(&keep);
+  if (have_dirs)
+    path_index_free(&dirs);
+  if (count_out)
+    *count_out = recorded;
+  return ok;
+}
+
+DeleteWalkResult delete_extras_limited_observed(const char* dest_root, const ArrayList* manifest,
+                                                const ArrayList* synced_dirs, size_t max_delete,
+                                                const DeleteSkipEntry* skips, int skip_count,
+                                                const FilterRuleList* protect_rules,
+                                                size_t* deleted_out, size_t* skipped_out,
+                                                DeletePathObserver observer,
+                                                void* observer_context) {
+  if (deleted_out)
+    *deleted_out = 0;
+  if (skipped_out)
+    *skipped_out = 0;
+  if (!manifest)
+    return DELETE_WALK_ERROR;
+  /* Index the keep-set (and the synchronized-dir set, when supplied) once so
+     membership is answered in O(path length) instead of scanning every entry
+     for every destination entry. */
+  PathIndex keep;
+  if (!build_keep_index(manifest, &keep))
+    return DELETE_WALK_ERROR;
+  PathIndex dirs;
+  bool have_dirs = synced_dirs != NULL;
+  if (have_dirs &&
+      !path_index_build(&dirs, (const char* const*)synced_dirs->items, (size_t)synced_dirs->size)) {
+    path_index_free(&keep);
+    return DELETE_WALK_ERROR;
+  }
+  int rootfd = open_destination_root(dest_root);
+  if (rootfd < 0) {
+    path_index_free(&keep);
+    if (have_dirs)
+      path_index_free(&dirs);
+    return DELETE_WALK_ERROR;
+  }
+  DeleteBudget budget = {.max_delete = max_delete, .deleted = 0, .skipped = 0, .limit_hit = false};
+  bool all_removed = false;
+  DeleteWalkState state = {.mode = DELETE_WALK_MODE_DELETE,
+                           .budget = &budget,
+                           .out = NULL,
+                           .recorded = NULL,
+                           .observer = observer,
+                           .observer_context = observer_context};
+  bool ok = delete_walk_fd(rootfd, "", &keep, have_dirs ? &dirs : NULL, &state, skips, skip_count,
+                           protect_rules, false, &all_removed);
+  if (close(rootfd) != 0)
+    ok = false;
+  path_index_free(&keep);
+  if (have_dirs)
+    path_index_free(&dirs);
+  if (deleted_out)
+    *deleted_out = budget.deleted;
+  if (skipped_out)
+    *skipped_out = budget.skipped;
+  if (!ok)
+    return DELETE_WALK_ERROR;
+  return budget.limit_hit ? DELETE_WALK_LIMIT_REACHED : DELETE_WALK_OK;
+}
+
+DeleteWalkResult delete_extras_limited(const char* dest_root, const ArrayList* manifest,
+                                       const ArrayList* synced_dirs, size_t max_delete,
+                                       const DeleteSkipEntry* skips, int skip_count,
+                                       const FilterRuleList* protect_rules, size_t* deleted_out,
+                                       size_t* skipped_out) {
+  return delete_extras_limited_observed(dest_root, manifest, synced_dirs, max_delete, skips,
+                                        skip_count, protect_rules, deleted_out, skipped_out, NULL,
+                                        NULL);
+}
+
+bool delete_extras(const char* dest_root, const ArrayList* manifest) {
+  return delete_extras_limited(dest_root, manifest, NULL, SIZE_MAX, NULL, 0, NULL, NULL, NULL) ==
+         DELETE_WALK_OK;
+}
+
+/* Build the delete-walk protection prefix for one basis directory.  The walker
+   compares paths relative to the receive root, so a relative entry is already
+   in the right form; an absolute entry that lies below the root is converted to
+   its root-relative form, and one outside the root returns NULL (the walk
+   cannot reach it, and it is not protected data beneath the root).  Exposed so
+   tests can exercise the root-of-"/" child mapping directly. */
+char* delete_basis_relative(const Config* config, const char* path) {
+  if (!path)
+    return NULL;
+  if (path[0] != '/')
+    return str_dup(path);
+  const char* root = config->receive_root_directory;
+  if (!root || root[0] != '/')
+    return NULL;
+  size_t root_len = strlen(root);
+  while (root_len > 1 && root[root_len - 1] == '/')
+    root_len--;
+  if (strncmp(path, root, root_len) != 0)
+    return NULL;
+  if (root_len == 1) {
+    /* `root` is "/" (the only single-character absolute root): every absolute
+       path is below it, and the child relative form is everything after the
+       leading '/'. */
+    if (path[1] == '\0')
+      return NULL; /* identical to the root, not a child */
+    return str_dup(path + 1);
+  }
+  if (path[root_len] != '/')
+    return NULL; /* identical or a sibling sharing a name prefix */
+  return str_dup(path + root_len + 1);
+}
+
+bool delete_skips_build(const Config* config, const ArrayList* protected_paths,
+                        const ArrayList* size_skipped, bool basis_root_relative,
+                        DeleteSkipSet* out) {
+  if (!out)
+    return false;
+  out->entries = NULL;
+  out->owned_prefixes = NULL;
+  out->count = 0;
+  out->owned_count = 0;
+  if (!config)
+    return false;
+  int protected_count = protected_paths ? protected_paths->size : 0;
+  int size_skipped_count = size_skipped ? size_skipped->size : 0;
+  int count =
+      (config->delay_updates ? 1 : 0) + config->basis_count + protected_count + size_skipped_count;
+  if (count == 0)
+    return true;
+  out->entries = calloc((size_t)count, sizeof(DeleteSkipEntry));
+  if (!out->entries)
+    return false;
+  if (basis_root_relative && config->basis_count > 0) {
+    out->owned_prefixes = calloc((size_t)config->basis_count, sizeof(char*));
+    if (!out->owned_prefixes) {
+      free(out->entries);
+      out->entries = NULL;
+      return false;
+    }
+    out->owned_count = config->basis_count;
+  }
+  int idx = 0;
+  if (config->delay_updates) {
+    out->entries[idx].prefix = DELAY_UPDATES_STAGING_DIR;
+    out->entries[idx].top_level_only = true;
+    idx++;
+  }
+  for (int i = 0; i < config->basis_count; i++) {
+    const char* prefix = config->basis_dirs[i].path;
+    if (basis_root_relative) {
+      /* An absolute basis outside the receive root is unreachable by this walk,
+         so it contributes no protection prefix (and no slot). */
+      char* relative = delete_basis_relative(config, config->basis_dirs[i].path);
+      if (!relative)
+        continue;
+      out->owned_prefixes[i] = relative;
+      prefix = relative;
+    }
+    out->entries[idx].prefix = prefix;
+    out->entries[idx].top_level_only = false;
+    idx++;
+  }
+  for (int i = 0; i < protected_count; i++) {
+    out->entries[idx].prefix = (const char*)protected_paths->items[i];
+    out->entries[idx].top_level_only = false;
+    idx++;
+  }
+  for (int i = 0; i < size_skipped_count; i++) {
+    out->entries[idx].prefix = (const char*)size_skipped->items[i];
+    out->entries[idx].top_level_only = false;
+    idx++;
+  }
+  out->count = idx;
+  return true;
+}
+
+void delete_skips_free(DeleteSkipSet* set) {
+  if (!set)
+    return;
+  if (set->owned_prefixes) {
+    for (int i = 0; i < set->owned_count; i++)
+      free(set->owned_prefixes[i]);
+  }
+  free(set->owned_prefixes);
+  free(set->entries);
+  set->entries = NULL;
+  set->owned_prefixes = NULL;
+  set->count = 0;
+  set->owned_count = 0;
+}

src/shared/delete.h

@@ -0,0 +1,151 @@
+#ifndef DELETE_H
+#define DELETE_H
+
+#include "array_list.h"
+#include "config.h"
+#include <stdbool.h>
+#include <stddef.h>
+
+/* Delete engine.
+ *
+ * This module owns destination-relative delete traversal: the ordered directory
+ * walker that reproduces rsync's extraneous-entry order, the skip-prefix
+ * protection set shared by every delete pass, and the read-only enumeration
+ * that mirrors the walker for -n/--dry-run.  The budgeted manifest commit
+ * (delete_commit.c) and the per-directory delete plans (delete_plan.c) are
+ * built on the primitives exported here. */
+
+/* Result of a bounded extra-file deletion run. */
+typedef enum {
+  /* Every extra entry was removed (or there were none). */
+  DELETE_WALK_OK = 0,
+  /* The numeric cap for this run was reached before every extra was removed.
+     The walker removed exactly the entries the cap allowed and skipped (without
+     removing) the rest, matching rsync's partial --max-delete behavior. */
+  DELETE_WALK_LIMIT_REACHED,
+  /* A traversal or unlink failure aborted the deletion (partial removal is
+     possible, mirroring the delete pass). */
+  DELETE_WALK_ERROR
+} DeleteWalkResult;
+
+/* One protected entry for the delete walker.  When top_level_only is true the
+   prefix is skipped only as a DIRECT child of dest_root (the --delay-updates
+   staging directory, which must not hide genuine extras inside a nested
+   destination directory that happens to share the staging name); otherwise the
+   prefix is skipped at any depth (the --compare-dest/--copy-dest/--link-dest
+   basis trees, and the sender-side protected filter-excluded prefixes, which
+   are never destination content). */
+typedef struct {
+  const char* prefix;
+  bool top_level_only;
+} DeleteSkipEntry;
+
+/* A built skip-prefix set.  `entries`/`count` are what path_under_skip_prefix()
+   consumes.  `owned_prefixes` holds any prefix strings the builder had to
+   allocate (root-relative basis-dir conversions); it is NULL when every prefix
+   is borrowed from the config or the caller's lists.  Release with
+   delete_skips_free(). */
+typedef struct {
+  DeleteSkipEntry* entries;
+  char** owned_prefixes;
+  int count;
+  int owned_count;
+} DeleteSkipSet;
+
+/* True when child_rel is, or lies below, one of the protected entries (a prefix
+   "a" protects "a" and "a/b/c" but not "ab"; top_level_only entries protect
+   only DIRECT children of the destination root, i.e. child_rel has no '/'). */
+bool path_under_skip_prefix(const char* child_rel, bool at_root, const DeleteSkipEntry* skips,
+                            int skip_count);
+
+/* One destination-directory entry collected up front so the delete walkers can
+   reproduce rsync's traversal order instead of readdir() order.  rsync processes
+   a directory's extraneous subdirectories first (descending name, depth-first),
+   then its extraneous files (descending name), and only afterwards descends into
+   its kept subdirectories (ascending name). */
+typedef struct {
+  char* name;
+  bool is_dir;
+} DeleteDirEntry;
+/* Collect the entries of the directory open on `dirfd` (excluding "." and ".."),
+   stat'ing each with AT_SYMLINK_NOFOLLOW.  On success *out is a malloc'd array of
+   *count entries whose names the caller frees with delete_dir_entries_free().
+   Returns false on an allocation/readdir failure; a vanished entry (ENOENT) is
+   skipped, any other stat failure is reported through *operation_ok while the
+   walk continues. */
+bool delete_dir_entries_collect(int dirfd, DeleteDirEntry** out, size_t* count, bool* operation_ok);
+void delete_dir_entries_free(DeleteDirEntry* entries, size_t count);
+/* Sort comparators: `_desc` orders subdirectories before files and each group by
+   descending name (rsync's extraneous-entry order); `_asc` orders plain ascending
+   name (rsync's kept-subdirectory order). */
+int delete_dir_entry_cmp_desc(const void* a, const void* b);
+int delete_dir_entry_cmp_asc(const void* a, const void* b);
+
+/* Remove files/dirs/symlinks under dest_root that are not listed in manifest
+   without ever descending into a protected prefix (see DeleteSkipEntry).  When
+   `synced_dirs` is non-NULL, extras are only removed directly inside a directory
+   whose destination-relative path is an exact entry in that list (the receive
+   root is the "." sentinel); directories outside the synchronized set are still
+   descended into so kept content below a listed directory is preserved, but
+   nothing in them is removed.  A NULL `synced_dirs` keeps the legacy behavior of
+   treating the whole destination tree as deletable.  `max_delete` caps the
+   number of removed entries (SIZE_MAX = unlimited): the walker removes up to the
+   cap and returns DELETE_WALK_LIMIT_REACHED when more extras remained.
+   `deleted_out`/`skipped_out` optionally receive the number of entries removed
+   and the number skipped because of the cap. */
+DeleteWalkResult delete_extras_limited(const char* dest_root, const ArrayList* manifest,
+                                       const ArrayList* synced_dirs, size_t max_delete,
+                                       const DeleteSkipEntry* skips, int skip_count,
+                                       const FilterRuleList* protect_rules, size_t* deleted_out,
+                                       size_t* skipped_out);
+
+/* Optional per-deletion observer: called for each destination-relative path
+   actually removed (a file, symlink, or directory), in removal order, so the
+   receiver can stream rsync's `--info=del`/`--info=remove` lines. */
+typedef void (*DeletePathObserver)(void* context, const char* rel_path);
+
+/* `delete_extras_limited_observed` is delete_extras_limited with an optional
+ * observer; the observer is invoked only for entries truly removed.  When
+ * `protect_rules` is non-NULL its receiver-side verdict is evaluated for every
+ * candidate extra: a first-match PROTECT leaves the entry (and, for a
+ * directory, its whole subtree) in place, while RISK/NONE fall through to the
+ * ordinary skip-prefix/keep-set logic. */
+DeleteWalkResult delete_extras_limited_observed(const char* dest_root, const ArrayList* manifest,
+                                                const ArrayList* synced_dirs, size_t max_delete,
+                                                const DeleteSkipEntry* skips, int skip_count,
+                                                const FilterRuleList* protect_rules,
+                                                size_t* deleted_out, size_t* skipped_out,
+                                                DeletePathObserver observer,
+                                                void* observer_context);
+/* Read-only companion to delete_extras_limited: walk the destination exactly as
+   the delete pass would and APPEND (strdup'd) destination-relative paths that
+   WOULD be removed, without touching disk.  Used for -n/--dry-run --delete
+   would-delete reporting.  Returns true on a clean walk; the caller owns the
+   strings appended to `out` and receives their count in *count_out. */
+bool delete_extras_list(const char* dest_root, const ArrayList* manifest,
+                        const ArrayList* synced_dirs, const DeleteSkipEntry* skips, int skip_count,
+                        const FilterRuleList* protect_rules, ArrayList* out, size_t* count_out);
+bool delete_extras(const char* dest_root, const ArrayList* manifest);
+
+/* Build the delete walk's skip-prefix set from the config's --delay-updates
+   staging directory, its --compare-dest/--copy-dest/--link-dest basis dirs, and
+   the caller-supplied protection lists, in that order.  `protected_paths` and
+   `size_skipped` are borrowed (may be NULL); every entry in them is protected at
+   any depth.  The staging directory is protected only as a DIRECT child of the
+   receive root.  `basis_root_relative` selects how a basis path becomes a
+   prefix: true converts an absolute path under the receive root to its
+   root-relative form (the whole-tree commit walk; an unreachable path
+   contributes no slot), false keeps the configured path verbatim (the
+   per-directory plan walk).  On success the caller releases `*out` with
+   delete_skips_free(); returns false on allocation failure. */
+bool delete_skips_build(const Config* config, const ArrayList* protected_paths,
+                        const ArrayList* size_skipped, bool basis_root_relative,
+                        DeleteSkipSet* out);
+void delete_skips_free(DeleteSkipSet* set);
+
+/* Convert one basis-directory path to the receive-root-relative protection
+   prefix the delete walker uses (NULL when it lies outside the root).  Exposed
+   for unit tests of the root-of-"/" and normalization edge cases. */
+char* delete_basis_relative(const Config* config, const char* path);
+
+#endif

src/shared/delete_commit.c

@@ -126,38 +126,6 @@ typedef struct {
   bool limit_hit;
 } DeleteBudgetState;
 
-/* Build the delete-walk protection prefix for one basis directory.  The walker
-   compares paths relative to the receive root, so a relative entry is already
-   in the right form; an absolute entry that lies below the root is converted to
-   its root-relative form, and one outside the root returns NULL (the walk
-   cannot reach it, and it is not protected data beneath the root).  Exposed so
-   tests can exercise the root-of-"/" child mapping directly. */
-char* file_receive_basis_delete_relative(const Config* config, const char* path) {
-  if (!path)
-    return NULL;
-  if (path[0] != '/')
-    return str_dup(path);
-  const char* root = config->receive_root_directory;
-  if (!root || root[0] != '/')
-    return NULL;
-  size_t root_len = strlen(root);
-  while (root_len > 1 && root[root_len - 1] == '/')
-    root_len--;
-  if (strncmp(path, root, root_len) != 0)
-    return NULL;
-  if (root_len == 1) {
-    /* `root` is "/" (the only single-character absolute root): every absolute
-       path is below it, and the child relative form is everything after the
-       leading '/'. */
-    if (path[1] == '\0')
-      return NULL; /* identical to the root, not a child */
-    return str_dup(path + 1);
-  }
-  if (path[root_len] != '/')
-    return NULL; /* identical or a sibling sharing a name prefix */
-  return str_dup(path + root_len + 1);
-}
-
 /* Remove every destination entry under the receive root that is not in the
    keep-set, bounded by the shared budget (a smaller client --max-delete=NUM
    replaces the server hard bound; rsync deletes up to the bound and skips the
@@ -168,61 +136,19 @@ char* file_receive_basis_delete_relative(const Config* config, const char* path)
    alternate basis directories are never destination content and are skipped at
    any depth.  Returns true unless a traversal/unlink error aborted the walk;
    the budget's limit_hit/skipped fields report a cap-stopped run. */
-static bool delete_extras_budgeted_observed(const Config* config, DeleteManifest* manifest,
+static bool delete_extras_budgeted_observed(const Config* config, const DeleteManifest* manifest,
                                             DeleteBudgetState* budget, DeletePathObserver observer,
                                             void* observer_context) {
   if (!config || !manifest || !manifest->keeps)
     return false;
   fprintf(stderr, "Deleting files not in manifest...\n");
-  /* Protected entries:
-     - the --delay-updates staging name, protected only as a DIRECT child of the
-       receive root (a nested destination directory that happens to be named
-       .fastsync-stage is ordinary content);
-     - alternate basis directories (--compare-dest / --copy-dest / --link-dest)
-       at any depth: they are extra comparison snapshots the user pointed at,
-       not destination content, and deleting them would destroy the very files a
-       --link-dest run just linked into place;
-     - the sender-side protected prefixes (source paths excluded by filters and
-       paths pruned by --max-size/--min-size), at any depth, so their destination
-       mirror survives --delete unless --delete-excluded opts back into removing
-       the filter-excluded ones (size-pruned entries are always protected). */
-  int skip_count = (config->delay_updates ? 1 : 0) + config->basis_count +
-                   (manifest->protected ? manifest->protected->size : 0);
-  DeleteSkipEntry* skips = NULL;
-  char** owned_prefixes = NULL;
-  int used = 0;
-  if (skip_count > 0) {
-    skips = calloc((size_t)skip_count, sizeof(DeleteSkipEntry));
-    owned_prefixes = calloc((size_t)config->basis_count, sizeof(char*));
-    if (!skips || (config->basis_count > 0 && !owned_prefixes)) {
-      free(skips);
-      free(owned_prefixes);
-      return false;
-    }
-    int idx = 0;
-    if (config->delay_updates) {
-      skips[idx].prefix = DELAY_UPDATES_STAGING_DIR;
-      skips[idx].top_level_only = true;
-      idx++;
-    }
-    for (int i = 0; i < config->basis_count; i++) {
-      /* An absolute basis outside the receive root is unreachable by this walk,
-         so it contributes no protection prefix (and no slot). */
-      char* prefix = file_receive_basis_delete_relative(config, config->basis_dirs[i].path);
-      if (!prefix)
-        continue;
-      owned_prefixes[i] = prefix;
-      skips[idx].prefix = prefix;
-      skips[idx].top_level_only = false;
-      idx++;
-    }
-    for (int i = 0; i < manifest->protected->size; i++) {
-      skips[idx].prefix = (const char*)manifest->protected->items[i];
-      skips[idx].top_level_only = false;
-      idx++;
-    }
-    used = idx;
-  }
+  /* Protected entries: the --delay-updates staging name (only as a DIRECT child
+     of the receive root), the alternate basis directories and the sender-side
+     protected prefixes (filter-excluded and size-pruned source mirrors), all at
+     any depth.  See delete_skips_build(). */
+  DeleteSkipSet skips;
+  if (!delete_skips_build(config, manifest->protected, NULL, true, &skips))
+    return false;
   /* Clamp rather than subtract: an accounting bug where deleted already exceeds
      max_delete must never underflow into an effectively unlimited budget. */
   size_t remaining;
@@ -235,14 +161,9 @@ static bool delete_extras_budgeted_observed(const Config* config, DeleteManifest
   size_t deleted = 0;
   size_t skipped = 0;
   DeleteWalkResult result = delete_extras_limited_observed(
-      config->receive_root_directory, manifest->keeps, manifest->dirs, remaining, skips, used,
-      config->protect_rules, &deleted, &skipped, observer, observer_context);
-  if (owned_prefixes) {
-    for (int i = 0; i < config->basis_count; i++)
-      free(owned_prefixes[i]);
-  }
-  free(owned_prefixes);
-  free(skips);
+      config->receive_root_directory, manifest->keeps, manifest->dirs, remaining, skips.entries,
+      skips.count, config->protect_rules, &deleted, &skipped, observer, observer_context);
+  delete_skips_free(&skips);
   budget->deleted += deleted;
   budget->skipped += skipped;
   if (result == DELETE_WALK_LIMIT_REACHED) {
@@ -256,7 +177,7 @@ static bool delete_extras_budgeted_observed(const Config* config, DeleteManifest
   return true;
 }
 
-static bool delete_extras_budgeted(const Config* config, DeleteManifest* manifest,
+static bool delete_extras_budgeted(const Config* config, const DeleteManifest* manifest,
                                    DeleteBudgetState* budget) {
   return delete_extras_budgeted_observed(config, manifest, budget, NULL, NULL);
 }
@@ -294,7 +215,8 @@ static void prefixed_delete_observer(void* context, const char* rel) {
    --max-delete budget: once it is exhausted the remaining requests are skipped
    and counted.  Returns false only on a genuine error (a confinement failure on
    a validated path or an I/O error), which fails the run. */
-static bool delete_missing_args_budgeted_observed(const Config* config, DeleteManifest* manifest,
+static bool delete_missing_args_budgeted_observed(const Config* config,
+                                                  const DeleteManifest* manifest,
                                                   DeleteBudgetState* budget,
                                                   DeletePathObserver observer,
                                                   void* observer_context) {
@@ -303,35 +225,12 @@ static bool delete_missing_args_budgeted_observed(const Config* config, DeleteMa
   if (!manifest->missing || manifest->missing->size == 0)
     return true;
   fprintf(stderr, "Deleting destination mirrors of missing source arguments...\n");
-  int skip_count = (config->delay_updates ? 1 : 0) + config->basis_count;
-  DeleteSkipEntry* skips = NULL;
-  char** owned_prefixes = NULL;
-  int used = 0;
-  if (skip_count > 0) {
-    skips = calloc((size_t)skip_count, sizeof(DeleteSkipEntry));
-    owned_prefixes = calloc((size_t)config->basis_count, sizeof(char*));
-    if (!skips || (config->basis_count > 0 && !owned_prefixes)) {
-      free(skips);
-      free(owned_prefixes);
-      return false;
-    }
-    int idx = 0;
-    if (config->delay_updates) {
-      skips[idx].prefix = DELAY_UPDATES_STAGING_DIR;
-      skips[idx].top_level_only = true;
-      idx++;
-    }
-    for (int i = 0; i < config->basis_count; i++) {
-      char* prefix = file_receive_basis_delete_relative(config, config->basis_dirs[i].path);
-      if (!prefix)
-        continue;
-      owned_prefixes[i] = prefix;
-      skips[idx].prefix = prefix;
-      skips[idx].top_level_only = false;
-      idx++;
-    }
-    used = idx;
-  }
+  /* The staging directory and basis snapshots stay protected exactly as in the
+     extras walker (the missing-args path overrides the ordinary protected
+     prefixes, so those are not passed here). */
+  DeleteSkipSet skips;
+  if (!delete_skips_build(config, NULL, NULL, true, &skips))
+    return false;
   bool ok = true;
   for (int i = 0; i < manifest->missing->size; i++) {
     const char* rel = (const char*)manifest->missing->items[i];
@@ -343,7 +242,7 @@ static bool delete_missing_args_budgeted_observed(const Config* config, DeleteMa
       continue;
     }
     bool at_root = strchr(rel, '/') == NULL;
-    if (path_under_skip_prefix(rel, at_root, skips, used)) {
+    if (path_under_skip_prefix(rel, at_root, skips.entries, skips.count)) {
       char* escaped = output_escape(rel, log_get_8_bit_output());
       log_message(LOG_LEVEL_WARNING,
                   "missing-args path '%s' is protected (staging directory or basis snapshot); "
@@ -472,96 +371,49 @@ static bool delete_missing_args_budgeted_observed(const Config* config, DeleteMa
     if (!ok)
       break;
   }
-  if (owned_prefixes) {
-    for (int i = 0; i < config->basis_count; i++)
-      free(owned_prefixes[i]);
-  }
-  free(owned_prefixes);
-  free(skips);
+  delete_skips_free(&skips);
   return ok;
 }
 
 /* Public wrappers used outside the commit path (and by unit tests): no
    --max-delete budget. */
-bool manifest_would_delete_list(const Config* config, DeleteManifest* manifest, ArrayList* out,
-                                size_t* count_out) {
+bool manifest_would_delete_list(const Config* config, const DeleteManifest* manifest,
+                                ArrayList* out, size_t* count_out) {
   if (count_out)
     *count_out = 0;
   if (!config || !manifest || !manifest->keeps || !out)
     return false;
-  int skip_count = (config->delay_updates ? 1 : 0) + config->basis_count +
-                   (manifest->protected ? manifest->protected->size : 0);
-  DeleteSkipEntry* skips = NULL;
-  char** owned_prefixes = NULL;
-  int used = 0;
-  if (skip_count > 0) {
-    skips = calloc((size_t)skip_count, sizeof(DeleteSkipEntry));
-    owned_prefixes = calloc((size_t)config->basis_count, sizeof(char*));
-    if (!skips || (config->basis_count > 0 && !owned_prefixes)) {
-      free(skips);
-      free(owned_prefixes);
-      return false;
-    }
-    int idx = 0;
-    if (config->delay_updates) {
-      skips[idx].prefix = DELAY_UPDATES_STAGING_DIR;
-      skips[idx].top_level_only = true;
-      idx++;
-    }
-    for (int i = 0; i < config->basis_count; i++) {
-      /* Normalize exactly like the real commit path: a relative entry is
-         already root-relative, an absolute one inside the receive root is
-         converted, and one outside contributes no protection prefix. */
-      char* prefix = file_receive_basis_delete_relative(config, config->basis_dirs[i].path);
-      if (!prefix)
-        continue;
-      owned_prefixes[i] = prefix;
-      skips[idx].prefix = prefix;
-      skips[idx].top_level_only = false;
-      idx++;
-    }
-    for (int i = 0; i < manifest->protected->size; i++) {
-      skips[idx].prefix = (const char*)manifest->protected->items[i];
-      skips[idx].top_level_only = false;
-      idx++;
-    }
-    used = idx;
-  }
+  DeleteSkipSet skips;
+  if (!delete_skips_build(config, manifest->protected, NULL, true, &skips))
+    return false;
   bool ok = delete_extras_list(config->receive_root_directory, manifest->keeps, manifest->dirs,
-                               skips, used, config->protect_rules, out, count_out);
-  if (owned_prefixes) {
-    for (int i = 0; i < config->basis_count; i++)
-      free(owned_prefixes[i]);
-  }
-  free(owned_prefixes);
-  free(skips);
+                               skips.entries, skips.count, config->protect_rules, out, count_out);
+  delete_skips_free(&skips);
   return ok;
 }
 
-bool manifest_delete_extras(const Config* config, DeleteManifest* manifest) {
+bool manifest_delete_extras(const Config* config, const DeleteManifest* manifest) {
   DeleteBudgetState budget = {
       .max_delete = SIZE_MAX, .deleted = 0, .skipped = 0, .limit_hit = false};
   return delete_extras_budgeted(config, manifest, &budget);
 }
 
-bool manifest_delete_missing_args(const Config* config, DeleteManifest* manifest) {
+bool manifest_delete_missing_args(const Config* config, const DeleteManifest* manifest) {
   DeleteBudgetState budget = {
       .max_delete = SIZE_MAX, .deleted = 0, .skipped = 0, .limit_hit = false};
   return delete_missing_args_budgeted_observed(config, manifest, &budget, NULL, NULL);
 }
 
-bool manifest_delete_missing_args_limited(const Config* config, DeleteManifest* manifest,
+bool manifest_delete_missing_args_limited(const Config* config, const DeleteManifest* manifest,
                                           size_t max_delete, size_t* deleted, size_t* skipped,
                                           bool* limit_hit) {
   return manifest_delete_missing_args_limited_observed(config, manifest, max_delete, deleted,
                                                        skipped, limit_hit, NULL, NULL);
 }
 
-bool manifest_delete_missing_args_limited_observed(const Config* config, DeleteManifest* manifest,
-                                                   size_t max_delete, size_t* deleted,
-                                                   size_t* skipped, bool* limit_hit,
-                                                   DeletePathObserver observer,
-                                                   void* observer_context) {
+bool manifest_delete_missing_args_limited_observed(
+    const Config* config, const DeleteManifest* manifest, size_t max_delete, size_t* deleted,
+    size_t* skipped, bool* limit_hit, DeletePathObserver observer, void* observer_context) {
   DeleteBudgetState budget = {
       .max_delete = max_delete, .deleted = 0, .skipped = 0, .limit_hit = false};
   bool ok =
@@ -582,17 +434,18 @@ bool manifest_delete_missing_args_limited_observed(const Config* config, DeleteM
    removal fail).  The ordinary extras walk then runs when --delete is active.
    Both draw from one --max-delete budget; the result reports a cap-stopped
    (partial) commit distinctly so the client can exit 25 like rsync. */
-DeleteCommitResult manifest_delete_all(const Config* config, DeleteManifest* manifest) {
+DeleteCommitResult manifest_delete_all(const Config* config, const DeleteManifest* manifest) {
   return manifest_delete_all_counted(config, manifest, NULL);
 }
 
-DeleteCommitResult manifest_delete_all_counted(const Config* config, DeleteManifest* manifest,
+DeleteCommitResult manifest_delete_all_counted(const Config* config, const DeleteManifest* manifest,
                                                size_t* deleted) {
   return manifest_delete_all_observed(config, manifest, deleted, NULL, NULL);
 }
 
-DeleteCommitResult manifest_delete_all_observed(const Config* config, DeleteManifest* manifest,
-                                                size_t* deleted, DeletePathObserver observer,
+DeleteCommitResult manifest_delete_all_observed(const Config* config,
+                                                const DeleteManifest* manifest, size_t* deleted,
+                                                DeletePathObserver observer,
                                                 void* observer_context) {
   if (deleted)
     *deleted = 0;

src/shared/delete_commit.h

@@ -3,7 +3,7 @@
 
 #include "array_list.h"
 #include "config.h"
-#include "utils.h"
+#include "delete.h"
 #include <stdbool.h>
 
 /* Delete-commit module: delete-manifest receive plus the budgeted extras and
@@ -44,7 +44,7 @@ DeleteManifest* receive_manifest_entries(int fd);
    protected-prefix skips).  `--max-delete` and `--force` are honored here.  The
    caller decides WHEN to run it based on the negotiated delete timing.  Returns
    false (and the transfer fails) when the deletion cannot be committed. */
-bool manifest_delete_extras(const Config* config, DeleteManifest* manifest);
+bool manifest_delete_extras(const Config* config, const DeleteManifest* manifest);
 /* --delete-missing-args exact-path deletions: remove each destination mirror
    in `manifest->missing` (never blocked by the protected prefixes, staging dir
    and basis dirs excluded).  A regular file/symlink is unlinked; an empty
@@ -53,22 +53,20 @@ bool manifest_delete_extras(const Config* config, DeleteManifest* manifest);
    parity).  A missing path is a no-op.  Returns false only on a genuine
    confinement or I/O error (the run then fails); tolerated per-path cases are
    reported and skipped. */
-bool manifest_delete_missing_args(const Config* config, DeleteManifest* manifest);
+bool manifest_delete_missing_args(const Config* config, const DeleteManifest* manifest);
 /* Budgeted form of manifest_delete_missing_args for the per-directory delete
    session: each removed mirror draws from `max_delete` (SIZE_MAX = unlimited)
    and the tallies are accumulated into `*deleted`/`*skipped`.  `*limit_hit` is set
    when the budget stopped the pass with entries left over.  Returns false only
    on a genuine deletion error. */
-bool manifest_delete_missing_args_limited(const Config* config, DeleteManifest* manifest,
+bool manifest_delete_missing_args_limited(const Config* config, const DeleteManifest* manifest,
                                           size_t max_delete, size_t* deleted, size_t* skipped,
                                           bool* limit_hit);
 /* Observer-aware form of manifest_delete_missing_args_limited: `observer` (may
    be NULL) is invoked for every destination-relative path truly removed. */
-bool manifest_delete_missing_args_limited_observed(const Config* config, DeleteManifest* manifest,
-                                                   size_t max_delete, size_t* deleted,
-                                                   size_t* skipped, bool* limit_hit,
-                                                   DeletePathObserver observer,
-                                                   void* observer_context);
+bool manifest_delete_missing_args_limited_observed(
+    const Config* config, const DeleteManifest* manifest, size_t max_delete, size_t* deleted,
+    size_t* skipped, bool* limit_hit, DeletePathObserver observer, void* observer_context);
 /* Outcome of committing a delete manifest.  LIMIT_REACHED reports rsync's
    partial --max-delete result: the budget allowed some deletions and the rest
    were skipped (the run still stores all file data but the client exits 25). */
@@ -84,15 +82,16 @@ typedef enum {
    share one --max-delete budget.  Returns DELETE_COMMIT_OK when nothing was to
    do or everything committed, DELETE_COMMIT_LIMIT_REACHED when the budget
    stopped part of the work, or DELETE_COMMIT_ERROR on a genuine failure. */
-DeleteCommitResult manifest_delete_all(const Config* config, DeleteManifest* manifest);
+DeleteCommitResult manifest_delete_all(const Config* config, const DeleteManifest* manifest);
 /* Like manifest_delete_all, but reports how many destination entries the commit
    removed (for the end-of-transfer wire stats).  `deleted` may be NULL. */
-DeleteCommitResult manifest_delete_all_counted(const Config* config, DeleteManifest* manifest,
+DeleteCommitResult manifest_delete_all_counted(const Config* config, const DeleteManifest* manifest,
                                                size_t* deleted);
 /* Observer-aware form of manifest_delete_all_counted: `observer` (may be NULL)
    is invoked for every destination-relative path truly removed. */
-DeleteCommitResult manifest_delete_all_observed(const Config* config, DeleteManifest* manifest,
-                                                size_t* deleted, DeletePathObserver observer,
+DeleteCommitResult manifest_delete_all_observed(const Config* config,
+                                                const DeleteManifest* manifest, size_t* deleted,
+                                                DeletePathObserver observer,
                                                 void* observer_context);
 
 /* -n/--dry-run --delete would-delete reporting: walk the destination exactly as
@@ -100,11 +99,7 @@ DeleteCommitResult manifest_delete_all_observed(const Config* config, DeleteMani
    WOULD be removed to `out`, without touching disk.  Uses the same staging-dir,
    basis-dir and protected-prefix skips as the real commit.  Returns true on a
    clean walk; `*count_out` receives the number of paths appended. */
-bool manifest_would_delete_list(const Config* config, DeleteManifest* manifest, ArrayList* out,
-                                size_t* count_out);
-/* Convert one basis-directory path to the receive-root-relative protection
-   prefix the delete walker uses (NULL when it lies outside the root).  Exposed
-   for unit tests of the root-of-"/" and normalization edge cases. */
-char* file_receive_basis_delete_relative(const Config* config, const char* path);
+bool manifest_would_delete_list(const Config* config, const DeleteManifest* manifest,
+                                ArrayList* out, size_t* count_out);
 
 #endif

src/shared/delete_plan.c

@@ -2,6 +2,7 @@
 
 #include "charset.h"
 #include "delay_updates.h"
+#include "delete.h"
 #include "file.h"
 #include "log.h"
 #include "utils.h"
@@ -601,9 +602,8 @@ static int open_plan_dir(const Config* config, const char* dir) {
   return fd;
 }
 
-typedef struct PlanSkips {
-  DeleteSkipEntry* entries;
-  int count;
+typedef struct {
+  DeleteSkipSet set;
   /* Receiver-side delete-protection rules received on the config frame (NULL
      when the sender sent none).  Evaluated per extra so a protect/risk rule is
      honored under --delete-during/--delete-delay exactly like the whole-tree
@@ -613,39 +613,12 @@ typedef struct PlanSkips {
 
 static bool build_plan_skips(const Config* config, const DeletePlanSession* session,
                              PlanSkips* out) {
-  out->entries = NULL;
-  out->count = 0;
   out->protect_rules = config->protect_rules;
-  int count = (config->delay_updates ? 1 : 0) + config->basis_count +
-              session->protected_prefixes->size + session->size_skipped->size;
-  if (count == 0)
-    return true;
-  out->entries = calloc((size_t)count, sizeof(DeleteSkipEntry));
-  if (!out->entries)
-    return false;
-  int idx = 0;
-  if (config->delay_updates) {
-    out->entries[idx].prefix = DELAY_UPDATES_STAGING_DIR;
-    out->entries[idx].top_level_only = true;
-    idx++;
-  }
-  for (int i = 0; i < config->basis_count; i++) {
-    out->entries[idx].prefix = config->basis_dirs[i].path;
-    out->entries[idx].top_level_only = false;
-    idx++;
-  }
-  for (int i = 0; i < session->protected_prefixes->size; i++) {
-    out->entries[idx].prefix = (const char*)session->protected_prefixes->items[i];
-    out->entries[idx].top_level_only = false;
-    idx++;
-  }
-  for (int i = 0; i < session->size_skipped->size; i++) {
-    out->entries[idx].prefix = (const char*)session->size_skipped->items[i];
-    out->entries[idx].top_level_only = false;
-    idx++;
-  }
-  out->count = idx;
-  return true;
+  /* The per-directory plan walk keeps each basis path verbatim (it does not
+     convert an absolute under-root path to its root-relative form, unlike the
+     whole-tree commit walk). */
+  return delete_skips_build(config, session->protected_prefixes, session->size_skipped, false,
+                            &out->set);
 }
 
 static bool budget_available(const DeletePlanSession* session) {
@@ -796,7 +769,7 @@ static bool process_children(int dirfd, const char* dir_rel, const ArrayList* ke
       operation_ok = false;
       continue;
     }
-    if (path_under_skip_prefix(child_rel, at_root, skips->entries, skips->count)) {
+    if (path_under_skip_prefix(child_rel, at_root, skips->set.entries, skips->set.count)) {
       shielded[i] = true;
       local_survives = true;
       free(child_rel);
@@ -883,7 +856,7 @@ static bool apply_plan_dir(DeletePlanSession* session, const Config* config, con
   bool survives = false;
   bool ok = process_children(dirfd, dir, dirs, files, strcmp(dir, ".") == 0, false, &skips, session,
                              &survives);
-  free(skips.entries);
+  delete_skips_free(&skips.set);
   close(dirfd);
   if (!ok)
     log_message(LOG_LEVEL_ERROR, "deletion failed while removing extraneous files");
@@ -1024,7 +997,7 @@ static bool apply_deferred_path(DeletePlanSession* session, const Config* config
     }
     bool survives = false;
     bool ok = process_children(dirfd, rel, NULL, NULL, false, true, &skips, session, &survives);
-    free(skips.entries);
+    delete_skips_free(&skips.set);
     close(dirfd);
     if (!ok) {
       close(parent_fd);

src/shared/delete_plan.h

@@ -3,6 +3,7 @@
 
 #include "array_list.h"
 #include "config.h"
+#include "delete.h"
 #include "file_receive.h"
 #include "protocol.h"
 #include "utils.h"

src/shared/file_send.c

@@ -185,7 +185,7 @@ bool file_send_sendfile_with_skip(File* file, int file_descriptor, bool use_meta
       return false;
     }
     protocol_note_bytes_written((unsigned long long)sent);
-    protocol_throttle_bytes((size_t)sent);
+    protocol_throttle_bytes(file_descriptor, (size_t)sent);
   }
 
   close(fd);

src/shared/protocol.c

@@ -302,11 +302,14 @@ static ProtocolSession* legacy_session(int read_fd, int write_fd) {
 }
 
 /* Pace an out-of-band write that bypassed protocol_send_n_data (the plaintext
- * sendfile fast path).  The bound/legacy session is resolved exactly as
- * send_n_data resolves it, so the same token-bucket state is throttled and the
- * TLS and plaintext transports share identical --bwlimit semantics. */
-void protocol_throttle_bytes(size_t bytes) {
-  bw_throttle_session(legacy_session(-1, -1), bytes);
+ * sendfile fast path).  The bound/legacy session is resolved exactly as the
+ * preceding send_n_data(fd, ...) resolved it, so the same token-bucket state is
+ * throttled and the TLS and plaintext transports share identical --bwlimit
+ * semantics.  Passing the wire fd (rather than -1) is essential: the sendfile
+ * send left legacy_io_session.write_fd bound to it, so resolving with -1 would
+ * mismatch, re-initialize the session and hand out a second first-call burst. */
+void protocol_throttle_bytes(int file_descriptor, size_t bytes) {
+  bw_throttle_session(legacy_session(-1, file_descriptor), bytes);
 }
 
 bool send_n_data(int file_descriptor, const void* data, size_t data_size) {

src/shared/protocol.h

@@ -225,11 +225,14 @@ unsigned long long protocol_bytes_written(void);
 unsigned long long protocol_bytes_read(void);
 void protocol_note_bytes_written(unsigned long long bytes);
 /* Apply --bwlimit pacing to bytes written outside protocol_send_n_data (the
- * plaintext zero-copy sendfile fast path).  Resolves the bound/legacy session
- * exactly as send_n_data does and runs the same token-bucket throttle, so the
- * sendfile transport is paced identically to the buffered/TLS paths.  A no-op
- * when the effective session has no bandwidth limit. */
-void protocol_throttle_bytes(size_t bytes);
+ * plaintext zero-copy sendfile fast path).  `file_descriptor` is the wire fd
+ * the bytes were written to, so the legacy session is resolved exactly as the
+ * preceding send_n_data call resolved it (the bound TLS session still wins when
+ * set); resolving with the same fd avoids re-initializing the legacy session
+ * and granting a second first-call burst.  Runs the same token-bucket throttle,
+ * so the sendfile transport is paced identically to the buffered/TLS paths.  A
+ * no-op when the effective session has no bandwidth limit. */
+void protocol_throttle_bytes(int file_descriptor, size_t bytes);
 
 void protocol_session_init(ProtocolSession* session, int read_fd, int write_fd);
 /* Transitional bridge for helpers whose signatures still carry only an fd. */

src/shared/utils.c

@@ -625,641 +625,6 @@ bool format_human_bytes(unsigned long long bytes, char* buffer, size_t buffer_si
   return written >= 0 && (size_t)written < buffer_size;
 }
 
-/* Build the keep-set index from the exact manifest entries only.  A lookup of
-   `rel` succeeds iff `rel` is a kept entry, a kept directory, or an ancestor
-   directory of kept content (the old is_dir_in_manifest predicate); the sorted
-   view answers "is an ancestor of kept content" without materializing any
-   per-component prefix copy, so the index is O(manifest size) memory. */
-static bool build_keep_index(const ArrayList* manifest, PathIndex* index) {
-  if (!manifest || manifest->size <= 0)
-    return path_index_build(index, NULL, 0);
-  return path_index_build(index, (const char* const*)manifest->items, (size_t)manifest->size);
-}
-
-static bool keep_is_dir(const PathIndex* index, const char* rel_path) {
-  return path_index_contains(index, rel_path) || path_index_has_descendant(index, rel_path);
-}
-
-static bool keep_is_file(const PathIndex* index, const char* rel_path) {
-  return path_index_contains(index, rel_path);
-}
-
-/* True when child_rel is, or lies below, a protected entry.  A prefix "a"
-   therefore protects "a" and "a/b/c" but not "ab".  Entries with top_level_only
-   set only protect DIRECT children of the receive root (at_root); nested
-   directories that share such a name stay ordinary destination content. */
-bool path_under_skip_prefix(const char* child_rel, bool at_root, const DeleteSkipEntry* skips,
-                            int skip_count) {
-  for (int i = 0; i < skip_count; i++) {
-    if (skips[i].top_level_only && !at_root)
-      continue;
-    size_t prefix_len = strlen(skips[i].prefix);
-    if (strncmp(child_rel, skips[i].prefix, prefix_len) == 0 &&
-        (child_rel[prefix_len] == '\0' || child_rel[prefix_len] == '/'))
-      return true;
-  }
-  return false;
-}
-
-/* Per-run deletion budget and tallies.  `max_delete` is the cap on the number
-   of entries the walker may remove (SIZE_MAX = unlimited); once it is reached
-   the remaining extras are counted in `skipped` and left in place, matching
-   rsync's partial --max-delete behavior. */
-typedef struct {
-  size_t max_delete;
-  size_t deleted;
-  size_t skipped;
-  bool limit_hit;
-} DeleteBudget;
-
-/* True when direct children of the directory named by `rel` may be removed.
-   With no synchronization info (dirs == NULL) the whole tree is deletable; when
-   a dirs index is supplied only its exact entries are (the receive root is the
-   "." sentinel). */
-static bool is_synced_dir(const PathIndex* dirs, const char* rel) {
-  if (!dirs)
-    return true;
-  return path_index_contains(dirs, rel[0] == '\0' ? "." : rel);
-}
-
-/* Unsigned byte-wise string compare, matching rsync's u_strcmp (a signed
-   strcmp would order bytes >= 0x80 differently). */
-static int delete_name_cmp(const char* a, const char* b) {
-  const unsigned char* pa = (const unsigned char*)a;
-  const unsigned char* pb = (const unsigned char*)b;
-  while (*pa != '\0' && *pa == *pb) {
-    pa++;
-    pb++;
-  }
-  return (int)*pa - (int)*pb;
-}
-
-bool delete_dir_entries_collect(int dirfd, DeleteDirEntry** out, size_t* count,
-                                bool* operation_ok) {
-  *out = NULL;
-  *count = 0;
-  if (operation_ok)
-    *operation_ok = true;
-  int scanfd = openat(dirfd, ".", O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
-  if (scanfd < 0)
-    return false;
-  DIR* dir = fdopendir(scanfd);
-  if (!dir) {
-    close(scanfd);
-    return false;
-  }
-  DeleteDirEntry* entries = NULL;
-  size_t used = 0;
-  size_t capacity = 0;
-  bool ok = true;
-  const struct dirent* entry;
-  while ((entry = readdir(dir)) != NULL) {
-    if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
-      continue;
-    struct stat st;
-    if (fstatat(dirfd, entry->d_name, &st, AT_SYMLINK_NOFOLLOW) != 0) {
-      if (errno != ENOENT && operation_ok)
-        *operation_ok = false;
-      continue;
-    }
-    if (used == capacity) {
-      size_t next = capacity == 0 ? 16 : capacity * 2;
-      DeleteDirEntry* grown = realloc(entries, next * sizeof(*grown));
-      if (!grown) {
-        ok = false;
-        break;
-      }
-      entries = grown;
-      capacity = next;
-    }
-    entries[used].name = str_dup(entry->d_name);
-    if (!entries[used].name) {
-      ok = false;
-      break;
-    }
-    entries[used].is_dir = S_ISDIR(st.st_mode);
-    used++;
-  }
-  closedir(dir);
-  if (!ok) {
-    delete_dir_entries_free(entries, used);
-    return false;
-  }
-  *out = entries;
-  *count = used;
-  return true;
-}
-
-void delete_dir_entries_free(DeleteDirEntry* entries, size_t count) {
-  if (!entries)
-    return;
-  for (size_t i = 0; i < count; i++)
-    free(entries[i].name);
-  free(entries);
-}
-
-/* rsync's extraneous-entry order: subdirectories before files, each group in
-   descending name order. */
-int delete_dir_entry_cmp_desc(const void* a, const void* b) {
-  const DeleteDirEntry* ea = a;
-  const DeleteDirEntry* eb = b;
-  if (ea->is_dir != eb->is_dir)
-    return ea->is_dir ? -1 : 1;
-  return -delete_name_cmp(ea->name, eb->name);
-}
-
-/* rsync's kept-subdirectory order: plain ascending name. */
-int delete_dir_entry_cmp_asc(const void* a, const void* b) {
-  const DeleteDirEntry* ea = a;
-  const DeleteDirEntry* eb = b;
-  return delete_name_cmp(ea->name, eb->name);
-}
-
-/* Remove the extras directly inside the directory open on `dirfd`, recursing
-   into every child directory so kept content below a synchronized prefix is
-   reached.  `all_removed` reports whether every child entry was removed (so the
-   caller may rmdir this directory).  A child directory is never removed when it
-   is itself a synchronized directory or holds kept content; with a dirs index
-   supplied, direct children of a non-synchronized directory are never extras at
-   all (they are left in place but still descended into).  Symlinks are unlinked
-   like any other non-directory extra (never followed).
-
-   Entries are processed in rsync's order (extraneous subdirectories in
-   descending name order, then extraneous files, then kept subdirectories in
-   ascending order) rather than readdir() order, so `--max-delete` leaves the
-   same survivors and the `--info=del`/dry-run line order matches rsync. */
-static bool delete_extras_fd(int dirfd, const char* rel_path, const PathIndex* keep,
-                             const PathIndex* dirs, DeleteBudget* budget,
-                             const DeleteSkipEntry* skips, int skip_count,
-                             const FilterRuleList* protect_rules, bool parent_deletable,
-                             bool* all_removed, DeletePathObserver observer,
-                             void* observer_context) {
-  DeleteDirEntry* entries = NULL;
-  size_t count = 0;
-  bool collect_ok = true;
-  if (!delete_dir_entries_collect(dirfd, &entries, &count, &collect_ok))
-    return false;
-  bool operation_ok = collect_ok;
-  bool local_survives = false;
-  bool* shielded = calloc(count ? count : 1, sizeof(bool));
-  bool* is_extra = calloc(count ? count : 1, sizeof(bool));
-  if (!shielded || !is_extra) {
-    free(shielded);
-    free(is_extra);
-    delete_dir_entries_free(entries, count);
-    return false;
-  }
-  /* A directory is deletable when it or ANY ancestor is synchronized; the
-     `parent_deletable` flag carries that down the recursion so dest-only
-     directories below a synchronized root are removed wholesale. */
-  bool deletable = parent_deletable || is_synced_dir(dirs, rel_path);
-  bool at_root = rel_path[0] == '\0';
-
-  /* Reproduce rsync's traversal order: extraneous subdirectories in descending
-     name order, then extraneous files in descending name order, and kept
-     subdirectories only afterwards (ascending).  Sorting up front also fixes the
-     identity of the survivors under a partial --max-delete. */
-  if (count > 1)
-    qsort(entries, count, sizeof(*entries), delete_dir_entry_cmp_desc);
-  size_t dir_count = 0;
-  while (dir_count < count && entries[dir_count].is_dir)
-    dir_count++;
-
-  /* Classify every entry up front (the verdict does not depend on processing
-     order) so the ordered passes below can act on it. */
-  for (size_t i = 0; i < count; i++) {
-    char* child_rel = path_cat((char*)rel_path, entries[i].name);
-    if (!child_rel) {
-      operation_ok = false;
-      continue;
-    }
-    /* A --delay-updates run keeps its staging directory as a direct child of
-       the receive root, and basis-dir snapshots live below it too.  Their
-       contents are not manifest entries, so descending into them would delete
-       every staged / basis file as an "extra".  Only the staging name (a
-       top-level-only prefix) and the basis prefixes are protected: a nested
-       destination directory that happens to be called .fastsync-stage is
-       ordinary content. */
-    if (path_under_skip_prefix(child_rel, at_root, skips, skip_count)) {
-      shielded[i] = true;
-      local_survives = true;
-    } else if (protect_rules &&
-               filter_rules_apply_side(protect_rules, child_rel, entries[i].name, entries[i].is_dir,
-                                       FILTER_SIDE_RECEIVER) == FILTER_ACTION_PROTECT) {
-      /* A first-match protect rule shields the extra; for a directory the whole
-         subtree is shielded (rsync prunes an excluded directory), so do not
-         descend. */
-      shielded[i] = true;
-      local_survives = true;
-    } else if (entries[i].is_dir) {
-      bool child_synced = dirs && path_index_contains(dirs, child_rel);
-      is_extra[i] = deletable && !child_synced && !keep_is_dir(keep, child_rel);
-      if (!is_extra[i])
-        local_survives = true;
-    } else {
-      is_extra[i] = deletable && !keep_is_file(keep, child_rel);
-      if (!is_extra[i])
-        local_survives = true;
-    }
-    free(child_rel);
-  }
-
-  /* Pass 1: extraneous subdirectories, descending. */
-  for (size_t i = 0; i < dir_count; i++) {
-    if (!is_extra[i])
-      continue;
-    char* child_rel = path_cat((char*)rel_path, entries[i].name);
-    if (!child_rel) {
-      operation_ok = false;
-      continue;
-    }
-    int childfd = openat(dirfd, entries[i].name, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
-    bool child_all_removed = false;
-    if (childfd >= 0) {
-      if (!delete_extras_fd(childfd, child_rel, keep, dirs, budget, skips, skip_count,
-                            protect_rules, deletable, &child_all_removed, observer,
-                            observer_context))
-        operation_ok = false;
-      close(childfd);
-    } else if (errno != ENOENT) {
-      operation_ok = false;
-    }
-    if (child_all_removed && deletable) {
-      if (budget->deleted >= budget->max_delete) {
-        budget->limit_hit = true;
-        budget->skipped++;
-        local_survives = true;
-      } else if (unlinkat(dirfd, entries[i].name, AT_REMOVEDIR) != 0) {
-        /* ENOENT: already gone (fine).  ENOTEMPTY/EEXIST: the directory still
-           holds entries the walker leaves in place (a protected excluded
-           prefix, a kept file the manifest protects, a symlink); rsync leaves
-           such a directory behind, so this is not an error.  Only genuine I/O
-           failures abort the deletion. */
-        if (errno != ENOENT && errno != ENOTEMPTY && errno != EEXIST)
-          operation_ok = false;
-        local_survives = true;
-      } else {
-        budget->deleted++;
-        /* rsync reports a removed directory with a trailing slash. */
-        if (observer) {
-          size_t len = strlen(child_rel);
-          char* with_slash = malloc(len + 2);
-          if (with_slash) {
-            memcpy(with_slash, child_rel, len);
-            with_slash[len] = '/';
-            with_slash[len + 1] = '\0';
-            observer(observer_context, with_slash);
-            free(with_slash);
-          } else {
-            observer(observer_context, child_rel);
-          }
-        }
-      }
-    } else {
-      local_survives = true;
-    }
-    free(child_rel);
-  }
-
-  /* Pass 2: extraneous files, descending. */
-  for (size_t i = dir_count; i < count; i++) {
-    if (!is_extra[i])
-      continue;
-    if (budget->deleted >= budget->max_delete) {
-      budget->limit_hit = true;
-      budget->skipped++;
-      local_survives = true;
-    } else if (unlinkat(dirfd, entries[i].name, 0) != 0) {
-      if (errno != ENOENT)
-        operation_ok = false;
-      local_survives = true;
-    } else {
-      budget->deleted++;
-      char* child_rel = path_cat((char*)rel_path, entries[i].name);
-      if (child_rel) {
-        if (observer)
-          observer(observer_context, child_rel);
-        char* escaped_path = output_escape(child_rel, log_get_8_bit_output());
-        fprintf(stderr, "  Deleted: %s\n", escaped_path ? escaped_path : "<allocation failed>");
-        free(escaped_path);
-      }
-      free(child_rel);
-    }
-  }
-
-  /* Pass 3: kept subdirectories, ascending (rsync descends into these only
-     after the parent's own extras have been handled). */
-  for (size_t i = dir_count; i-- > 0;) {
-    if (is_extra[i] || shielded[i])
-      continue;
-    char* child_rel = path_cat((char*)rel_path, entries[i].name);
-    if (!child_rel) {
-      operation_ok = false;
-      continue;
-    }
-    int childfd = openat(dirfd, entries[i].name, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
-    bool child_all_removed = false;
-    if (childfd >= 0) {
-      if (!delete_extras_fd(childfd, child_rel, keep, dirs, budget, skips, skip_count,
-                            protect_rules, deletable, &child_all_removed, observer,
-                            observer_context))
-        operation_ok = false;
-      close(childfd);
-    } else if (errno != ENOENT) {
-      operation_ok = false;
-    }
-    /* A kept/synchronized directory is never removed. */
-    local_survives = true;
-    free(child_rel);
-  }
-
-  free(shielded);
-  free(is_extra);
-  delete_dir_entries_free(entries, count);
-  *all_removed = !local_survives;
-  return operation_ok;
-}
-
-/* Read-only mirror of delete_extras_fd: records the paths that WOULD be removed
-   without unlinking anything.  A child directory is reported after its own
-   reportable children (depth-first), matching the delete pass's ordering. */
-static bool list_extras_fd(int dirfd, const char* rel_path, const PathIndex* keep,
-                           const PathIndex* dirs, ArrayList* out, size_t* recorded,
-                           const DeleteSkipEntry* skips, int skip_count,
-                           const FilterRuleList* protect_rules, bool parent_deletable,
-                           bool* all_removed) {
-  DeleteDirEntry* entries = NULL;
-  size_t count = 0;
-  bool collect_ok = true;
-  if (!delete_dir_entries_collect(dirfd, &entries, &count, &collect_ok))
-    return false;
-  bool operation_ok = collect_ok;
-  bool local_survives = false;
-  bool* shielded = calloc(count ? count : 1, sizeof(bool));
-  bool* is_extra = calloc(count ? count : 1, sizeof(bool));
-  if (!shielded || !is_extra) {
-    free(shielded);
-    free(is_extra);
-    delete_dir_entries_free(entries, count);
-    return false;
-  }
-  bool deletable = parent_deletable || is_synced_dir(dirs, rel_path);
-  bool at_root = rel_path[0] == '\0';
-
-  /* Mirror the delete walk's rsync order (extraneous subdirectories descending,
-     then extraneous files descending, then kept subdirectories ascending). */
-  if (count > 1)
-    qsort(entries, count, sizeof(*entries), delete_dir_entry_cmp_desc);
-  size_t dir_count = 0;
-  while (dir_count < count && entries[dir_count].is_dir)
-    dir_count++;
-
-  for (size_t i = 0; i < count; i++) {
-    char* child_rel = path_cat((char*)rel_path, entries[i].name);
-    if (!child_rel) {
-      operation_ok = false;
-      continue;
-    }
-    if (path_under_skip_prefix(child_rel, at_root, skips, skip_count)) {
-      shielded[i] = true;
-      local_survives = true;
-    } else if (protect_rules &&
-               filter_rules_apply_side(protect_rules, child_rel, entries[i].name, entries[i].is_dir,
-                                       FILTER_SIDE_RECEIVER) == FILTER_ACTION_PROTECT) {
-      /* Mirror the delete walk: a protected entry is never reported as a
-         would-delete and a protected directory's subtree is not enumerated. */
-      shielded[i] = true;
-      local_survives = true;
-    } else if (entries[i].is_dir) {
-      bool child_synced = dirs && path_index_contains(dirs, child_rel);
-      is_extra[i] = deletable && !child_synced && !keep_is_dir(keep, child_rel);
-      if (!is_extra[i])
-        local_survives = true;
-    } else {
-      is_extra[i] = deletable && !keep_is_file(keep, child_rel);
-      if (!is_extra[i])
-        local_survives = true;
-    }
-    free(child_rel);
-  }
-
-  /* Pass 1: extraneous subdirectories, descending (recorded after contents). */
-  for (size_t i = 0; i < dir_count; i++) {
-    if (!is_extra[i])
-      continue;
-    char* child_rel = path_cat((char*)rel_path, entries[i].name);
-    if (!child_rel) {
-      operation_ok = false;
-      continue;
-    }
-    int childfd = openat(dirfd, entries[i].name, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
-    bool child_all_removed = false;
-    if (childfd >= 0) {
-      if (!list_extras_fd(childfd, child_rel, keep, dirs, out, recorded, skips, skip_count,
-                          protect_rules, deletable, &child_all_removed))
-        operation_ok = false;
-      close(childfd);
-    } else if (errno != ENOENT) {
-      operation_ok = false;
-    }
-    if (child_all_removed && deletable) {
-      size_t len = strlen(child_rel);
-      char* copy = malloc(len + 2);
-      if (!copy) {
-        operation_ok = false;
-      } else {
-        memcpy(copy, child_rel, len);
-        copy[len] = '/';
-        copy[len + 1] = '\0';
-        if (!array_list_add(out, copy)) {
-          free(copy);
-          operation_ok = false;
-        } else {
-          (*recorded)++;
-        }
-      }
-    } else {
-      local_survives = true;
-    }
-    free(child_rel);
-  }
-
-  /* Pass 2: extraneous files, descending. */
-  for (size_t i = dir_count; i < count; i++) {
-    if (!is_extra[i])
-      continue;
-    char* child_rel = path_cat((char*)rel_path, entries[i].name);
-    if (!child_rel) {
-      operation_ok = false;
-      continue;
-    }
-    char* copy = str_dup(child_rel);
-    if (!copy || !array_list_add(out, copy)) {
-      free(copy);
-      operation_ok = false;
-    } else {
-      (*recorded)++;
-    }
-    free(child_rel);
-  }
-
-  /* Pass 3: kept subdirectories, ascending. */
-  for (size_t i = dir_count; i-- > 0;) {
-    if (is_extra[i] || shielded[i])
-      continue;
-    char* child_rel = path_cat((char*)rel_path, entries[i].name);
-    if (!child_rel) {
-      operation_ok = false;
-      continue;
-    }
-    int childfd = openat(dirfd, entries[i].name, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
-    bool child_all_removed = false;
-    if (childfd >= 0) {
-      if (!list_extras_fd(childfd, child_rel, keep, dirs, out, recorded, skips, skip_count,
-                          protect_rules, deletable, &child_all_removed))
-        operation_ok = false;
-      close(childfd);
-    } else if (errno != ENOENT) {
-      operation_ok = false;
-    }
-    local_survives = true;
-    free(child_rel);
-  }
-
-  free(shielded);
-  free(is_extra);
-  delete_dir_entries_free(entries, count);
-  *all_removed = !local_survives;
-  return operation_ok;
-}
-
-bool delete_extras_list(const char* dest_root, const ArrayList* manifest,
-                        const ArrayList* synced_dirs, const DeleteSkipEntry* skips, int skip_count,
-                        const FilterRuleList* protect_rules, ArrayList* out, size_t* count_out) {
-  if (count_out)
-    *count_out = 0;
-  if (!manifest || !out)
-    return false;
-  PathIndex keep;
-  if (!build_keep_index(manifest, &keep))
-    return false;
-  PathIndex dirs;
-  bool have_dirs = synced_dirs != NULL;
-  if (have_dirs &&
-      !path_index_build(&dirs, (const char* const*)synced_dirs->items, (size_t)synced_dirs->size)) {
-    path_index_free(&keep);
-    return false;
-  }
-  int rootfd;
-  int root_fd = utils_get_authorized_root_fd();
-  if (root_fd >= 0) {
-    if (utils_get_authorized_root_path())
-      rootfd = utils_open_authorized_destination(dest_root);
-    else if (dest_root == NULL)
-      rootfd = dup(root_fd);
-    else
-      rootfd = -1;
-  } else {
-    rootfd = open(dest_root, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
-  }
-  if (rootfd < 0) {
-    path_index_free(&keep);
-    if (have_dirs)
-      path_index_free(&dirs);
-    return false;
-  }
-  bool all_removed = false;
-  size_t recorded = 0;
-  bool ok = list_extras_fd(rootfd, "", &keep, have_dirs ? &dirs : NULL, out, &recorded, skips,
-                           skip_count, protect_rules, false, &all_removed);
-  if (close(rootfd) != 0)
-    ok = false;
-  path_index_free(&keep);
-  if (have_dirs)
-    path_index_free(&dirs);
-  if (count_out)
-    *count_out = recorded;
-  return ok;
-}
-
-DeleteWalkResult delete_extras_limited_observed(const char* dest_root, const ArrayList* manifest,
-                                                const ArrayList* synced_dirs, size_t max_delete,
-                                                const DeleteSkipEntry* skips, int skip_count,
-                                                const FilterRuleList* protect_rules,
-                                                size_t* deleted_out, size_t* skipped_out,
-                                                DeletePathObserver observer,
-                                                void* observer_context) {
-  if (deleted_out)
-    *deleted_out = 0;
-  if (skipped_out)
-    *skipped_out = 0;
-  if (!manifest)
-    return DELETE_WALK_ERROR;
-  /* Index the keep-set (and the synchronized-dir set, when supplied) once so
-     membership is answered in O(path length) instead of scanning every entry
-     for every destination entry. */
-  PathIndex keep;
-  if (!build_keep_index(manifest, &keep))
-    return DELETE_WALK_ERROR;
-  PathIndex dirs;
-  bool have_dirs = synced_dirs != NULL;
-  if (have_dirs &&
-      !path_index_build(&dirs, (const char* const*)synced_dirs->items, (size_t)synced_dirs->size)) {
-    path_index_free(&keep);
-    return DELETE_WALK_ERROR;
-  }
-  int rootfd;
-  int root_fd = utils_get_authorized_root_fd();
-  if (root_fd >= 0) {
-    if (utils_get_authorized_root_path())
-      rootfd = utils_open_authorized_destination(dest_root);
-    else if (dest_root == NULL)
-      rootfd = dup(root_fd);
-    else
-      rootfd = -1;
-  } else {
-    rootfd = open(dest_root, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
-  }
-  if (rootfd < 0) {
-    path_index_free(&keep);
-    if (have_dirs)
-      path_index_free(&dirs);
-    return DELETE_WALK_ERROR;
-  }
-  DeleteBudget budget = {.max_delete = max_delete, .deleted = 0, .skipped = 0, .limit_hit = false};
-  bool all_removed = false;
-  bool ok =
-      delete_extras_fd(rootfd, "", &keep, have_dirs ? &dirs : NULL, &budget, skips, skip_count,
-                       protect_rules, false, &all_removed, observer, observer_context);
-  if (close(rootfd) != 0)
-    ok = false;
-  path_index_free(&keep);
-  if (have_dirs)
-    path_index_free(&dirs);
-  if (deleted_out)
-    *deleted_out = budget.deleted;
-  if (skipped_out)
-    *skipped_out = budget.skipped;
-  if (!ok)
-    return DELETE_WALK_ERROR;
-  return budget.limit_hit ? DELETE_WALK_LIMIT_REACHED : DELETE_WALK_OK;
-}
-
-DeleteWalkResult delete_extras_limited(const char* dest_root, const ArrayList* manifest,
-                                       const ArrayList* synced_dirs, size_t max_delete,
-                                       const DeleteSkipEntry* skips, int skip_count,
-                                       const FilterRuleList* protect_rules, size_t* deleted_out,
-                                       size_t* skipped_out) {
-  return delete_extras_limited_observed(dest_root, manifest, synced_dirs, max_delete, skips,
-                                        skip_count, protect_rules, deleted_out, skipped_out, NULL,
-                                        NULL);
-}
-
-bool delete_extras(const char* dest_root, const ArrayList* manifest) {
-  return delete_extras_limited(dest_root, manifest, NULL, SIZE_MAX, NULL, 0, NULL, NULL, NULL) ==
-         DELETE_WALK_OK;
-}
-
 bool has_path_traversal(const char* path) {
   if (!path)
     return true;

src/shared/utils.h

@@ -106,101 +106,7 @@ int env_choice_first(const char* env_name, int (*resolve)(const char*), bool* sp
 ssize_t utils_getdelim_bounded(FILE* stream, char** line, size_t* cap, int delim, size_t max_len);
 char* path_cat(const char* path1, const char* path2);
 bool glob_match(const char* pattern, const char* str);
-/* Result of a bounded extra-file deletion run. */
-typedef enum {
-  /* Every extra entry was removed (or there were none). */
-  DELETE_WALK_OK = 0,
-  /* The numeric cap for this run was reached before every extra was removed.
-     The walker removed exactly the entries the cap allowed and skipped (without
-     removing) the rest, matching rsync's partial --max-delete behavior. */
-  DELETE_WALK_LIMIT_REACHED,
-  /* A traversal or unlink failure aborted the deletion (partial removal is
-     possible, mirroring the delete pass). */
-  DELETE_WALK_ERROR
-} DeleteWalkResult;
-/* One protected entry for the delete walker.  When top_level_only is true the
-   prefix is skipped only as a DIRECT child of dest_root (the --delay-updates
-   staging directory, which must not hide genuine extras inside a nested
-   destination directory that happens to share the staging name); otherwise the
-   prefix is skipped at any depth (the --compare-dest/--copy-dest/--link-dest
-   basis trees, and the sender-side protected filter-excluded prefixes, which
-   are never destination content). */
-typedef struct {
-  const char* prefix;
-  bool top_level_only;
-} DeleteSkipEntry;
-/* True when child_rel is, or lies below, one of the protected entries (a prefix
-   "a" protects "a" and "a/b/c" but not "ab"; top_level_only entries protect
-   only DIRECT children of the destination root, i.e. child_rel has no '/'). */
-bool path_under_skip_prefix(const char* child_rel, bool at_root, const DeleteSkipEntry* skips,
-                            int skip_count);
-/* One destination-directory entry collected up front so the delete walkers can
-   reproduce rsync's traversal order instead of readdir() order.  rsync processes
-   a directory's extraneous subdirectories first (descending name, depth-first),
-   then its extraneous files (descending name), and only afterwards descends into
-   its kept subdirectories (ascending name). */
-typedef struct {
-  char* name;
-  bool is_dir;
-} DeleteDirEntry;
-/* Collect the entries of the directory open on `dirfd` (excluding "." and ".."),
-   stat'ing each with AT_SYMLINK_NOFOLLOW.  On success *out is a malloc'd array of
-   *count entries whose names the caller frees with delete_dir_entries_free().
-   Returns false on an allocation/readdir failure; a vanished entry (ENOENT) is
-   skipped, any other stat failure is reported through *operation_ok while the
-   walk continues. */
-bool delete_dir_entries_collect(int dirfd, DeleteDirEntry** out, size_t* count, bool* operation_ok);
-void delete_dir_entries_free(DeleteDirEntry* entries, size_t count);
-/* Sort comparators: `_desc` orders subdirectories before files and each group by
-   descending name (rsync's extraneous-entry order); `_asc` orders plain ascending
-   name (rsync's kept-subdirectory order). */
-int delete_dir_entry_cmp_desc(const void* a, const void* b);
-int delete_dir_entry_cmp_asc(const void* a, const void* b);
-/* Remove files/dirs/symlinks under dest_root that are not listed in manifest
-   without ever descending into a protected prefix (see DeleteSkipEntry).  When
-   `synced_dirs` is non-NULL, extras are only removed directly inside a directory
-   whose destination-relative path is an exact entry in that list (the receive
-   root is the "." sentinel); directories outside the synchronized set are still
-   descended into so kept content below a listed directory is preserved, but
-   nothing in them is removed.  A NULL `synced_dirs` keeps the legacy behavior of
-   treating the whole destination tree as deletable.  `max_delete` caps the
-   number of removed entries (SIZE_MAX = unlimited): the walker removes up to the
-   cap and returns DELETE_WALK_LIMIT_REACHED when more extras remained.
-   `deleted_out`/`skipped_out` optionally receive the number of entries removed
-   and the number skipped because of the cap. */
-DeleteWalkResult delete_extras_limited(const char* dest_root, const ArrayList* manifest,
-                                       const ArrayList* synced_dirs, size_t max_delete,
-                                       const DeleteSkipEntry* skips, int skip_count,
-                                       const FilterRuleList* protect_rules, size_t* deleted_out,
-                                       size_t* skipped_out);
 
-/* Optional per-deletion observer: called for each destination-relative path
-   actually removed (a file, symlink, or directory), in removal order, so the
-   receiver can stream rsync's `--info=del`/`--info=remove` lines. */
-typedef void (*DeletePathObserver)(void* context, const char* rel_path);
-
-/* `delete_extras_limited_observed` is delete_extras_limited with an optional
- * observer; the observer is invoked only for entries truly removed.  When
- * `protect_rules` is non-NULL its receiver-side verdict is evaluated for every
- * candidate extra: a first-match PROTECT leaves the entry (and, for a
- * directory, its whole subtree) in place, while RISK/NONE fall through to the
- * ordinary skip-prefix/keep-set logic. */
-DeleteWalkResult delete_extras_limited_observed(const char* dest_root, const ArrayList* manifest,
-                                                const ArrayList* synced_dirs, size_t max_delete,
-                                                const DeleteSkipEntry* skips, int skip_count,
-                                                const FilterRuleList* protect_rules,
-                                                size_t* deleted_out, size_t* skipped_out,
-                                                DeletePathObserver observer,
-                                                void* observer_context);
-/* Read-only companion to delete_extras_limited: walk the destination exactly as
-   the delete pass would and APPEND (strdup'd) destination-relative paths that
-   WOULD be removed, without touching disk.  Used for -n/--dry-run --delete
-   would-delete reporting.  Returns true on a clean walk; the caller owns the
-   strings appended to `out` and receives their count in *count_out. */
-bool delete_extras_list(const char* dest_root, const ArrayList* manifest,
-                        const ArrayList* synced_dirs, const DeleteSkipEntry* skips, int skip_count,
-                        const FilterRuleList* protect_rules, ArrayList* out, size_t* count_out);
-bool delete_extras(const char* dest_root, const ArrayList* manifest);
 /* Open the existing destination directory at `dest_root`, confined to the
    authorized root with an O_NOFOLLOW component walk (the same confinement the
    deletion walker uses for its root).  Returns a new fd the caller owns, or -1

tests/integration/test_temp_dir_exdev.py

@@ -0,0 +1,80 @@
+"""End-to-end coverage for the `--temp-dir` EXDEV (cross-filesystem) fallback.
+
+`file_to_disk_secure_impl` installs a completed temp file with `renameat(2)`;
+when the scratch dir lives on a different filesystem the rename fails with
+`EXDEV` and the engine retries with no scratch dir, writing the file directly in
+the destination directory (a non-atomic copy), matching rsync.
+
+The daemon receiver confines `--temp-dir` to the authorized receive root, so a
+genuine cross-fs scratch there would require an in-root mount point.  Bind/tmpfs
+mounting is not permitted in the CI container (no `CAP_SYS_ADMIN`, and
+unprivileged user namespaces are disabled), so this test reaches the exact same
+code path through the local `--read-batch` apply instead: it has no
+authorized-root confinement, so a relative `--temp-dir` that is a symlink to a
+tmpfs (`/dev/shm`) is accepted and the final install then crosses filesystems.
+"""
+import os
+import shutil
+import subprocess
+import sys
+
+import pytest
+
+sys.path.insert(0, os.path.dirname(__file__))
+from common import CLIENT_CMD, get_dest_received_dir
+
+TMPFS = "/dev/shm"
+
+
+def _run(args):
+    return subprocess.run(CLIENT_CMD + args, capture_output=True, text=True, timeout=180)
+
+
+def _read(path):
+    with open(path, "rb") as fh:
+        return fh.read()
+
+
+def test_read_batch_temp_dir_cross_filesystem_fallback(tmp_path):
+    if not os.path.isdir(TMPFS):
+        pytest.skip("no /dev/shm tmpfs available to force a cross-filesystem install")
+
+    source = tmp_path / "src"
+    dest = tmp_path / "dst"
+    source.mkdir()
+    dest.mkdir()
+    files = {
+        "payload.bin": bytes(range(256)) * 64,
+        "sub/nested.txt": b"nested exdev fallback\n" * 8,
+    }
+    for rel, data in files.items():
+        full = source / rel
+        full.parent.mkdir(parents=True, exist_ok=True)
+        full.write_bytes(data)
+
+    batch = tmp_path / "tree.batch"
+    r = _run(["--only-write-batch", str(batch), str(source)])
+    assert r.returncode == 0, (r.stdout, r.stderr)
+
+    # A cross-filesystem scratch dir, reached through a relative --temp-dir
+    # symlink (the local batch apply performs no authorized-root confinement).
+    scratch = os.path.join(TMPFS, "fastsync_exdev_%d" % os.getpid())
+    shutil.rmtree(scratch, ignore_errors=True)
+    os.makedirs(scratch)
+    os.symlink(scratch, dest / "scratch")
+    try:
+        assert os.stat(scratch).st_dev != os.stat(dest).st_dev, (
+            "scratch and destination share a filesystem; EXDEV cannot be exercised"
+        )
+        r = _run(["--read-batch", str(batch), str(dest), "--temp-dir=scratch"])
+        assert r.returncode == 0, (r.stdout, r.stderr)
+        # The engine must report the non-atomic cross-fs fallback rather than
+        # silently claiming an atomic install.
+        assert "different filesystem" in (r.stdout + r.stderr), (r.stdout, r.stderr)
+        # The tree is still byte-exact and the scratch dir is left clean.
+        received = get_dest_received_dir(str(dest), str(source))
+        for rel, data in files.items():
+            assert _read(os.path.join(received, rel)) == data, f"content mismatch for {rel}"
+        assert os.listdir(scratch) == [], "cross-fs temp file was not cleaned up"
+    finally:
+        shutil.rmtree(scratch, ignore_errors=True)

tests/test_change_list.c

@@ -195,7 +195,7 @@ static void test_format_C_padding_uses_transfer_algo() {
       {CHECKSUM_ALGO_NONE, 2},
   };
   for (size_t i = 0; i < sizeof(cases) / sizeof(cases[0]); i++) {
-    config->checksum_transfer_algo = cases[i].algo;
+    config->cli.checksum_transfer_algo = cases[i].algo;
     char expected[64];
     size_t n = 0;
     expected[n++] = '[';

tests/test_client_cli.c

@@ -730,7 +730,7 @@ static void test_parse_args_port_alias() {
   EXPECT_EQ_INT(cfg->server_port, 9000);
   /* The default port is 8080; the explicit bit is what lets --dry-run tell an
      explicit remote target from the default and route to the server. */
-  EXPECT_TRUE(cfg->server_port_set);
+  EXPECT_TRUE(cfg->cli.server_port_set);
   config_delete(cfg);
 
   cfg = config_create();
@@ -738,7 +738,7 @@ static void test_parse_args_port_alias() {
   positional_count = 0;
   EXPECT_EQ_INT(parse_args(cfg, 4, argv_inline, positional_args, &positional_count), 0);
   EXPECT_EQ_INT(cfg->server_port, 9001);
-  EXPECT_TRUE(cfg->server_port_set);
+  EXPECT_TRUE(cfg->cli.server_port_set);
   config_delete(cfg);
 
   cfg = config_create();
@@ -746,7 +746,7 @@ static void test_parse_args_port_alias() {
   positional_count = 0;
   EXPECT_EQ_INT(parse_args(cfg, 4, argv_long, positional_args, &positional_count), 0);
   EXPECT_EQ_INT(cfg->server_port, 9002);
-  EXPECT_TRUE(cfg->server_port_set);
+  EXPECT_TRUE(cfg->cli.server_port_set);
   config_delete(cfg);
 }
 
@@ -757,18 +757,18 @@ static void test_parse_args_server_host_sets_routing_bit() {
   Config* cfg = config_create();
   int positional_args[2];
   int positional_count = 0;
-  EXPECT_FALSE(cfg->server_host_set);
+  EXPECT_FALSE(cfg->cli.server_host_set);
   char* argv_space[] = {"fastsync", "--server-host", "example.test", "/src", "/dst"};
   EXPECT_EQ_INT(parse_args(cfg, 5, argv_space, positional_args, &positional_count), 0);
   EXPECT_EQ_STR(cfg->server_host, "example.test");
-  EXPECT_TRUE(cfg->server_host_set);
+  EXPECT_TRUE(cfg->cli.server_host_set);
   config_delete(cfg);
 
   cfg = config_create();
   char* argv_inline[] = {"fastsync", "--server-host=example.test", "/src", "/dst"};
   positional_count = 0;
   EXPECT_EQ_INT(parse_args(cfg, 4, argv_inline, positional_args, &positional_count), 0);
-  EXPECT_TRUE(cfg->server_host_set);
+  EXPECT_TRUE(cfg->cli.server_host_set);
   config_delete(cfg);
 }
 
@@ -1726,7 +1726,7 @@ static void test_parse_args_no_preserve_blocks_implicit_metadata() {
 
     EXPECT_EQ_INT(parse_args(cfg, 5, argv, positional_args, &positional_count), 0);
     EXPECT_FALSE(cfg->use_metadata);
-    EXPECT_TRUE(cfg->metadata_explicitly_disabled);
+    EXPECT_TRUE(cfg->cli.metadata_explicitly_disabled);
     config_delete(cfg);
   }
 }
@@ -1777,7 +1777,7 @@ static void test_parse_args_checksum_choice_rejects_unsupported() {
     int positional_args[2];
     int positional_count = 0;
     EXPECT_EQ_INT(parse_args(cfg, 5, argv, positional_args, &positional_count), -1);
-    EXPECT_EQ_INT(cfg->cli_exit_code, 4);
+    EXPECT_EQ_INT(cfg->cli.cli_exit_code, 4);
     config_delete(cfg);
   }
 }
@@ -1817,7 +1817,7 @@ static void test_parse_args_checksum_choice_new_algos() {
     positional_count = 0;
     EXPECT_EQ_INT(parse_args(cfg, 5, argv4, positional_args, &positional_count), 0);
     EXPECT_EQ_INT(cfg->checksum_algo, single[i]);
-    EXPECT_EQ_INT(cfg->checksum_transfer_algo, single[i]);
+    EXPECT_EQ_INT(cfg->cli.checksum_transfer_algo, single[i]);
     config_delete(cfg);
   }
 
@@ -1827,7 +1827,7 @@ static void test_parse_args_checksum_choice_new_algos() {
   char* argv5[] = {"fastsync", "--cc=sha1,md4", "/checksum/src", "/dst"};
   positional_count = 0;
   EXPECT_EQ_INT(parse_args(cfg, 4, argv5, positional_args, &positional_count), 0);
-  EXPECT_EQ_INT(cfg->checksum_transfer_algo, (int)CHECKSUM_ALGO_SHA1);
+  EXPECT_EQ_INT(cfg->cli.checksum_transfer_algo, (int)CHECKSUM_ALGO_SHA1);
   EXPECT_EQ_INT(cfg->checksum_algo, (int)CHECKSUM_ALGO_MD4);
   config_delete(cfg);
 
@@ -1849,14 +1849,14 @@ static void test_parse_args_checksum_none_with_checksum_rejected() {
   int positional_args[2];
   int positional_count = 0;
   EXPECT_EQ_INT(parse_args(cfg, 5, argv, positional_args, &positional_count), -1);
-  EXPECT_EQ_INT(cfg->cli_exit_code, 4);
+  EXPECT_EQ_INT(cfg->cli.cli_exit_code, 4);
   config_delete(cfg);
 
   cfg = config_create();
   char* argv2[] = {"fastsync", "--checksum", "--cc=md5,none", "/checksum/src", "/dst"};
   positional_count = 0;
   EXPECT_EQ_INT(parse_args(cfg, 5, argv2, positional_args, &positional_count), -1);
-  EXPECT_EQ_INT(cfg->cli_exit_code, 4);
+  EXPECT_EQ_INT(cfg->cli.cli_exit_code, 4);
   config_delete(cfg);
 
   /* "none" as the TRANSFER checksum with a real pre-transfer checksum is
@@ -1958,7 +1958,7 @@ static void test_parse_args_compress_choice_parity() {
     int positional_args[2];
     int positional_count = 0;
     EXPECT_EQ_INT(parse_args(cfg, 5, argv, positional_args, &positional_count), -1);
-    EXPECT_EQ_INT(cfg->cli_exit_code, 4);
+    EXPECT_EQ_INT(cfg->cli.cli_exit_code, 4);
     config_delete(cfg);
   }
 }
@@ -2078,6 +2078,9 @@ static void test_parse_args_temp_dir() {
   config_delete(cfg);
 }
 
+/* --old-args is accepted for rsync CLI compatibility as a documented no-op (the
+ * remote server path is always safely quoted); it stores no Config field, so
+ * parsing it must simply succeed and leave the positional arguments intact. */
 static void test_parse_args_old_args() {
   Config* cfg = config_create();
   char* argv[] = {"fastsync", "--old-args", "/src", "/dst"};
@@ -2085,7 +2088,7 @@ static void test_parse_args_old_args() {
   int positional_count = 0;
 
   EXPECT_EQ_INT(parse_args(cfg, 4, argv, positional_args, &positional_count), 0);
-  EXPECT_TRUE(cfg->old_args);
+  EXPECT_EQ_INT(positional_count, 2);
   config_delete(cfg);
 }
 
@@ -2719,7 +2722,7 @@ static void test_parse_args_compression_env_list() {
   cfg = config_create();
   positional_count = 0;
   EXPECT_EQ_INT(parse_args(cfg, 4, argv, positional_args, &positional_count), -1);
-  EXPECT_EQ_INT(cfg->cli_exit_code, 4);
+  EXPECT_EQ_INT(cfg->cli.cli_exit_code, 4);
   config_delete(cfg);
   unsetenv("RSYNC_COMPRESS_LIST");
 }
@@ -2734,7 +2737,7 @@ static void test_parse_args_checksum_env_list() {
   setenv("RSYNC_CHECKSUM_LIST", "md5", 1);
   EXPECT_EQ_INT(parse_args(cfg, 4, argv, positional_args, &positional_count), 0);
   EXPECT_EQ_INT(cfg->checksum_algo, (int)CHECKSUM_ALGO_MD5);
-  EXPECT_EQ_INT(cfg->checksum_transfer_algo, (int)CHECKSUM_ALGO_MD5);
+  EXPECT_EQ_INT(cfg->cli.checksum_transfer_algo, (int)CHECKSUM_ALGO_MD5);
   config_delete(cfg);
 
   /* An explicit --cc wins. */
@@ -2750,7 +2753,7 @@ static void test_parse_args_checksum_env_list() {
   cfg = config_create();
   positional_count = 0;
   EXPECT_EQ_INT(parse_args(cfg, 4, argv, positional_args, &positional_count), -1);
-  EXPECT_EQ_INT(cfg->cli_exit_code, 4);
+  EXPECT_EQ_INT(cfg->cli.cli_exit_code, 4);
   config_delete(cfg);
   unsetenv("RSYNC_CHECKSUM_LIST");
 }
@@ -4385,7 +4388,7 @@ static void test_parse_args_preserve_long_form() {
 }
 
 /* --no-perms/--no-times/--no-owner/--no-group (long and short) clear only
- * their own attribute bit; they never set metadata_explicitly_disabled. */
+ * their own attribute bit; they never set cli.metadata_explicitly_disabled. */
 static void test_parse_args_preserve_negations() {
   struct {
     const char* arg;
@@ -4413,7 +4416,7 @@ static void test_parse_args_preserve_negations() {
       bool expected = all[j] != cases[i].offset;
       EXPECT_TRUE(*(bool*)((char*)cfg + all[j]) == expected);
     }
-    EXPECT_FALSE(cfg->metadata_explicitly_disabled);
+    EXPECT_FALSE(cfg->cli.metadata_explicitly_disabled);
     /* -a's devices/specials keep the metadata frame on. */
     EXPECT_TRUE(cfg->use_metadata);
     config_delete(cfg);
@@ -4456,7 +4459,7 @@ static void test_parse_args_no_preserve_disables_bundle() {
   EXPECT_FALSE(cfg->preserve_times);
   EXPECT_FALSE(cfg->preserve_owner);
   EXPECT_FALSE(cfg->preserve_group);
-  EXPECT_TRUE(cfg->metadata_explicitly_disabled);
+  EXPECT_TRUE(cfg->cli.metadata_explicitly_disabled);
   EXPECT_TRUE(cfg->use_incremental);
   EXPECT_FALSE(cfg->use_metadata);
   config_delete(cfg);
@@ -4509,7 +4512,7 @@ static void test_parse_args_incremental_implies_preserve() {
   EXPECT_EQ_INT(parse_args(cfg, 5, argv4, positional_args, &positional_count), 0);
   EXPECT_FALSE(cfg->preserve_perms);
   EXPECT_FALSE(cfg->preserve_times);
-  EXPECT_TRUE(cfg->metadata_explicitly_disabled);
+  EXPECT_TRUE(cfg->cli.metadata_explicitly_disabled);
   EXPECT_FALSE(cfg->use_metadata);
   config_delete(cfg);
 }

tests/test_config.c

@@ -2533,15 +2533,15 @@ static void test_config_derived_use_metadata() {
   /* Incremental/delta imply metadata unless --no-preserve disabled it. */
   c->use_incremental = true;
   EXPECT_TRUE(config_derived_use_metadata(c));
-  c->metadata_explicitly_disabled = true;
+  c->cli.metadata_explicitly_disabled = true;
   EXPECT_FALSE(config_derived_use_metadata(c));
-  c->metadata_explicitly_disabled = false;
+  c->cli.metadata_explicitly_disabled = false;
   c->use_incremental = false;
   c->use_delta = true;
   EXPECT_TRUE(config_derived_use_metadata(c));
-  c->metadata_explicitly_disabled = true;
+  c->cli.metadata_explicitly_disabled = true;
   EXPECT_FALSE(config_derived_use_metadata(c));
-  c->metadata_explicitly_disabled = false;
+  c->cli.metadata_explicitly_disabled = false;
   c->use_delta = false;
 
   /* Flags that must NOT imply metadata on their own. */

tests/test_file.c

@@ -2255,26 +2255,26 @@ static void test_basis_delete_relative_root_slash() {
   EXPECT_NOT_NULL(cfg);
   cfg->receive_root_directory = str_dup("/");
 
-  char* rel = file_receive_basis_delete_relative(cfg, "/a");
+  char* rel = delete_basis_relative(cfg, "/a");
   EXPECT_NOT_NULL(rel);
   EXPECT_EQ_STR(rel, "a");
   free(rel);
-  rel = file_receive_basis_delete_relative(cfg, "/a/b");
+  rel = delete_basis_relative(cfg, "/a/b");
   EXPECT_NOT_NULL(rel);
   EXPECT_EQ_STR(rel, "a/b");
   free(rel);
   /* The root itself is not a child. */
-  EXPECT_NULL(file_receive_basis_delete_relative(cfg, "/"));
+  EXPECT_NULL(delete_basis_relative(cfg, "/"));
   /* A relative entry is already root-relative. */
-  rel = file_receive_basis_delete_relative(cfg, "x/y");
+  rel = delete_basis_relative(cfg, "x/y");
   EXPECT_NOT_NULL(rel);
   EXPECT_EQ_STR(rel, "x/y");
   free(rel);
   /* An absolute path outside a non-"/" root is unreachable. */
   free(cfg->receive_root_directory);
   cfg->receive_root_directory = str_dup("/root");
-  EXPECT_NULL(file_receive_basis_delete_relative(cfg, "/other/a"));
-  rel = file_receive_basis_delete_relative(cfg, "/root/a");
+  EXPECT_NULL(delete_basis_relative(cfg, "/other/a"));
+  rel = delete_basis_relative(cfg, "/root/a");
   EXPECT_NOT_NULL(rel);
   EXPECT_EQ_STR(rel, "a");
   free(rel);

tests/test_protocol.c

@@ -1,6 +1,8 @@
 #include "protocol.h"
 #include "test_utils.h"
+#include <fcntl.h>
 #include <limits.h>
+#include <stdlib.h>
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
@@ -715,7 +717,7 @@ static void test_protocol_throttle_bytes_paces() {
 
   struct timespec start;
   clock_gettime(CLOCK_MONOTONIC, &start);
-  protocol_throttle_bytes(150000);
+  protocol_throttle_bytes(-1, 150000);
   struct timespec now;
   clock_gettime(CLOCK_MONOTONIC, &now);
   long long elapsed_ms =
@@ -736,7 +738,7 @@ static void test_protocol_throttle_bytes_unlimited() {
 
   struct timespec start;
   clock_gettime(CLOCK_MONOTONIC, &start);
-  protocol_throttle_bytes(100000000ULL);
+  protocol_throttle_bytes(-1, 100000000ULL);
   struct timespec now;
   clock_gettime(CLOCK_MONOTONIC, &now);
   long long elapsed_ms =
@@ -746,6 +748,44 @@ static void test_protocol_throttle_bytes_unlimited() {
   protocol_session_unbind();
 }
 
+/* Regression for the plaintext sendfile path: it calls protocol_throttle_bytes()
+ * immediately after send_n_data(), which already bound legacy_io_session.write_fd
+ * to the wire fd.  Resolving the throttle session with (read=-1, write=-1)
+ * mismatched that fd and re-initialized the legacy session, granting a *second*
+ * first-call burst and discarding the accumulated debt.  This drives the same
+ * sequence and asserts the debt from send_n_data carries into the throttle. */
+static void test_protocol_throttle_bytes_legacy_same_session() {
+  const size_t payload = 150000; /* 1.5x the 100 KB burst at --bwlimit=1 MB/s */
+  unsigned char* buffer = malloc(payload);
+  EXPECT_TRUE(buffer != NULL);
+  memset(buffer, 0, payload);
+
+  io_set_fds(-1, -1);
+  io_set_bwlimit(1000000ULL);
+
+  int fd = open("/dev/null", O_WRONLY);
+  EXPECT_TRUE(fd >= 0);
+
+  struct timespec start;
+  clock_gettime(CLOCK_MONOTONIC, &start);
+  /* send_n_data() consumes the whole 100 KB burst and sleeps ~50 ms. */
+  EXPECT_TRUE(send_n_data(fd, buffer, payload));
+  /* The throttle must share that session, so the 150 KB is all debt and sleeps
+     ~150 ms (total ~200 ms).  A re-initialized session would hand out a fresh
+     100 KB burst and sleep only ~50 ms (total ~100 ms). */
+  protocol_throttle_bytes(fd, payload);
+  struct timespec now;
+  clock_gettime(CLOCK_MONOTONIC, &now);
+  long long elapsed_ms =
+      (now.tv_sec - start.tv_sec) * 1000LL + (now.tv_nsec - start.tv_nsec) / 1000000LL;
+  EXPECT_TRUE(elapsed_ms >= 150);
+
+  close(fd);
+  free(buffer);
+  io_set_bwlimit(0);
+  io_set_fds(-1, -1);
+}
+
 void test_protocol() {
   test_send_receive_n_data();
   test_send_receive_n_data_zero();
@@ -778,4 +818,5 @@ void test_protocol() {
   test_data_create_starts_uncharged_and_unowned();
   test_protocol_throttle_bytes_paces();
   test_protocol_throttle_bytes_unlimited();
+  test_protocol_throttle_bytes_legacy_same_session();
 }

tests/test_shared_utils.c

@@ -1,4 +1,5 @@
 #include "test_shared_utils.h"
+#include "delete.h"
 #include "utils.h"
 #include "protocol.h"
 #include "test_utils.h"