feat: implement -R/--relative, --no-implied-dirs, --dirs/-d, --mkpath

RSYNC_COMPAT Phase-2 row M: path-list construction and destination
directory creation while preserving traversal safety.

- -R/--relative with --files-from: transmit each listed entry under its
  bare relative destination path (no source-root mirror). Files keep an
  absolute local read path plus a separate wire/dest path (File.send_path);
  manifest, incremental quick-check and change output follow the wire path,
  so --delete and --remove-source-files stay consistent. -R without
  --files-from is unchanged (full mirror).
- --no-implied-dirs: client-only, only meaningful with -R + --files-from.
  A listed file whose parent dir is not itself (or via an ancestor)
  explicitly listed cannot be placed; the run fails up front with a clear
  error. No effect otherwise.
- --dirs/-d + --old-dirs/--old-d aliases: -d <dir> transmits the source
  root as an explicit empty directory entry (STATUS_MKDIR frame); with
  --files-from listed dirs are created empty and listed files transferred,
  never descending. Works single-threaded, -m (sequential scanner in the
  -m scan thread) and chunk-serialization (per-file type marker).
  Directory entries appear in the delete manifest.
- --mkpath: new wire bool; server creates the destination root (and missing
  leading components under its authorized root) at connection start. A
  missing destination root is now rejected by default.
- Protocol bumped to 2.7.0 (mkpath wire field + STATUS_MKDIR + chunk type
  marker). All receive paths funnel through file_save_to_disk_full which
  creates directories via the secure confined mkdir engine; dir entries are
  excluded from --remove-source-files outcome acknowledgements on both ends.
- Unit coverage: CLI parse (relative/dirs aliases/mkpath/no-implied-dirs),
  config round-trip (relative + mkpath), scanner --dirs non-recursion and
  -R send_path (sequential + parallel), receiver dir-entry save.
- Integration coverage: TestRelativeFilesFrom, TestNoImpliedDirs, TestDirs,
  TestMkpath (single and -m).
- RSYNC_COMPAT: 4 rows move to Implemented (Summary 67/3/5/1/71 = 147).

src/client/change_list.c

@@ -289,7 +289,10 @@ void change_emit_file_sent(const Config* config, const File* file) {
     return;
   ChangeEvent event;
   memset(&event, 0, sizeof(event));
-  event.path = file->path;
+  /* The displayed path is the one transmitted (with -R + --files-from this is
+     the bare relative destination path); the metadata fallback below still
+     stats the local absolute path. */
+  event.path = file_wire_path(file);
   event.decision = CHANGE_SENT;
   event.is_directory = false;
   event.size = file->data != NULL ? file->data->size : 0;
@@ -308,3 +311,19 @@ void change_emit_file_sent(const Config* config, const File* file) {
   }
   change_emit(config, &event);
 }
+
+/* Build and emit a CHANGE_SENT event for an explicit directory entry (-d). */
+void change_emit_dir_sent(const Config* config, const File* file) {
+  if (file == NULL || !change_list_enabled(config))
+    return;
+  ChangeEvent event;
+  memset(&event, 0, sizeof(event));
+  event.path = file_wire_path(file);
+  event.decision = CHANGE_SENT;
+  event.is_directory = true;
+  event.size = 0;
+  event.bytes_sent = 0;
+  if (file->metadata != NULL)
+    event.mtime_sec = file->metadata->mtime_sec;
+  change_emit(config, &event);
+}

src/client/change_list.h

@@ -72,4 +72,7 @@ void change_emit(const Config* config, const ChangeEvent* event);
 /* Build and emit a CHANGE_SENT event for a file the client just sent. */
 void change_emit_file_sent(const Config* config, const File* file);
 
+/* Build and emit a CHANGE_SENT event for an explicit directory entry (-d). */
+void change_emit_dir_sent(const Config* config, const File* file);
+
 #endif

src/client/client_cli.c

@@ -425,8 +425,12 @@ static const OptionEntry OPTION_TABLE[] = {
     {"--ignore-existing", NULL, OPT_FLAG, offsetof(Config, ignore_existing)},
     {"--delay-updates", NULL, OPT_FLAG, offsetof(Config, delay_updates)},
     {"--chmod", NULL, OPT_STRING, offsetof(Config, chmod_spec)},
-    {"--dirs", "--old-dirs", OPT_UNSUPPORTED, 0},
-    {"--old-d", NULL, OPT_UNSUPPORTED, 0},
+    {"--dirs", "-d", OPT_FLAG, offsetof(Config, dirs)},
+    {"--old-dirs", NULL, OPT_FLAG, offsetof(Config, dirs)},
+    {"--old-d", NULL, OPT_FLAG, offsetof(Config, dirs)},
+    {"--relative", "-R", OPT_FLAG, offsetof(Config, relative)},
+    {"--no-implied-dirs", NULL, OPT_FLAG, offsetof(Config, no_implied_dirs)},
+    {"--mkpath", NULL, OPT_FLAG, offsetof(Config, mkpath)},
     {"--delete-during", "--del", OPT_UNSUPPORTED, 0},
 
     {"--source-dir", NULL, OPT_STRING, offsetof(Config, send_directory)},
@@ -576,9 +580,7 @@ static int apply_table_option(Config* config, const OptionEntry* entry, const ch
     return 0;
   }
   case OPT_UNSUPPORTED: {
-    const char* reason = "directory-only transfer is not implemented";
-    if (strcmp(entry->name, "--delete-during") == 0)
-      reason = "delete-during is not implemented";
+    const char* reason = "delete-during is not implemented";
     log_message(LOG_LEVEL_ERROR, "%s: %s; refusing to ignore option", option_name, reason);
     return -1;
   }
@@ -611,6 +613,13 @@ int parse_args(Config* config, int argc, char* argv[], int* positional_args,
       config->show_progress = true;
       continue;
     }
+    /* "--no-implied-dirs" is a real rsync option name, not a negation of
+     * "--implied-dirs", so it must be handled before the generic --no-*
+     * negation branch. */
+    if (strcmp(argv[i], "--no-implied-dirs") == 0) {
+      config->no_implied_dirs = true;
+      continue;
+    }
     if (strncmp(argv[i], "--no-", strlen("--no-")) == 0) {
       if (apply_negation(config, argv[i]) != 0)
         return -1;

src/client/client_send.c

@@ -100,6 +100,8 @@ static bool prepare_scanner(const Config* config, int num_threads, PreparedScann
   options->file_list = (const FileListSet*)config->files_from_set;
   options->base_filters = out->base_filters;
   options->per_dir_filters = config->per_dir_filter;
+  options->dirs = config->dirs;
+  options->relative = config->relative;
   return true;
 }
 
@@ -110,6 +112,72 @@ static void prepared_scanner_destroy(PreparedScanner* prepared) {
   prepared->base_filters = NULL;
 }
 
+/* True when some --files-from entry is an ancestor-or-equal directory of
+ * `rel` (an empty entry -- the whole tree "." -- counts as the root). */
+static bool file_list_ancestor_listed(const FileListSet* set, const char* rel) {
+  if (!set)
+    return true;
+  for (int i = 0; i < set->count; i++) {
+    const char* listed = set->entries[i];
+    if (listed[0] == '\0')
+      return true;
+    size_t n = strlen(listed);
+    if (strncmp(rel, listed, n) == 0 && (rel[n] == '/' || rel[n] == '\0'))
+      return true;
+  }
+  return false;
+}
+
+/* --no-implied-dirs (meaningful only with -R + --files-from): a listed file
+ * may only be placed when its parent directory (or one of its ancestors) is
+ * itself an explicitly listed entry.  rsync omits a file whose implied parent
+ * directory is suppressed, and an explicitly listed file that cannot be placed
+ * fails the transfer; FastSync fails the whole run up front with a clear error
+ * (it has no per-entry skip channel).  Without -R or --files-from the option
+ * has no effect. */
+static bool no_implied_dirs_files_from_valid(const Config* config) {
+  if (!config->no_implied_dirs || !config->relative)
+    return true;
+  const FileListSet* set = (const FileListSet*)config->files_from_set;
+  if (!set)
+    return true;
+  for (int i = 0; i < set->count; i++) {
+    const char* entry = set->entries[i];
+    if (entry[0] == '\0')
+      continue;
+    char* full = path_cat(config->send_directory, entry);
+    if (!full)
+      return false;
+    struct stat st;
+    bool is_file = lstat(full, &st) == 0 && S_ISREG(st.st_mode);
+    free(full);
+    if (!is_file)
+      continue;
+    const char* slash = strrchr(entry, '/');
+    if (!slash)
+      continue; /* top-level file: its parent is the receive root */
+    size_t parent_len = (size_t)(slash - entry);
+    if (parent_len == 0)
+      continue;
+    char* parent = malloc(parent_len + 1);
+    if (!parent)
+      return false;
+    memcpy(parent, entry, parent_len);
+    parent[parent_len] = '\0';
+    bool listed = file_list_ancestor_listed(set, parent);
+    if (!listed) {
+      log_message(LOG_LEVEL_ERROR,
+                  "--no-implied-dirs: cannot place file '%s': parent directory '%s' is not "
+                  "explicitly listed (list the directory or drop --no-implied-dirs)",
+                  entry, parent);
+    }
+    free(parent);
+    if (!listed)
+      return false;
+  }
+  return true;
+}
+
 /* --files-from semantics: every listed entry must resolve under the source
  * root, otherwise rsync reports a hard error instead of silently transferring
  * nothing. An empty list is also an error. An entry of "." (the whole tree)
@@ -147,7 +215,7 @@ static bool files_from_list_valid(const Config* config) {
     }
     free(full);
   }
-  return true;
+  return no_implied_dirs_files_from_valid(config);
 }
 
 /* Select the configured transport for both transfer execution paths. */
@@ -194,7 +262,7 @@ static bool add_chunk_to_manifest(ArrayList* manifest, const Chunk* chunk) {
   if (!manifest)
     return true;
   for (int i = 0; i < chunk->element_count; i++) {
-    const char* path = chunk->items[i]->path;
+    const char* path = file_wire_path(chunk->items[i]);
     if (*path == '/')
       path++;
     char* entry = str_dup(path);
@@ -533,7 +601,7 @@ static int incremental_check(Client* client, File* file, const Config* config,
   *out_sig = NULL;
   if (!send_status(client->file_descriptor, STATUS_CHECK))
     return -1;
-  if (!send_str(client->file_descriptor, file->path))
+  if (!send_str(client->file_descriptor, file_wire_path(file)))
     return -1;
   unsigned long long fsize = file->data->size;
   long long mtime = file->metadata ? file->metadata->mtime_sec : 0;
@@ -633,6 +701,17 @@ static bool send_file_direct(File* file, int fd, bool use_metadata, int compress
                                           config->compression_threads);
 }
 
+/* Transmit one explicit directory entry (--dirs): a STATUS_MKDIR frame whose
+   payload is only the destination path.  The receiver validates the path and
+   creates the directory under the receive root. */
+static bool send_directory_entry(Client* client, File* file) {
+  if (!file || !file_wire_path(file))
+    return false;
+  if (!send_status(client->file_descriptor, STATUS_MKDIR))
+    return false;
+  return send_str(client->file_descriptor, file_wire_path(file));
+}
+
 // Send a single file directly via sendfile (non-incremental path).
 static bool send_file_direct_sendfile(File* file, int fd, bool use_metadata, const Config* config) {
   if (!send_status(fd, STATUS_NEXT))
@@ -755,7 +834,11 @@ static int send_chunk_with_removal(Client* client, Chunk* chunk, Config* config,
     }
     data_destroy(data);
     for (int i = 0; i < chunk->element_count; i++) {
-      if (chunk->items[i] != NULL)
+      if (chunk->items[i] == NULL)
+        continue;
+      if (chunk->items[i]->is_dir)
+        change_emit_dir_sent(config, chunk->items[i]);
+      else
         change_emit_file_sent(config, chunk->items[i]);
     }
     return 0;
@@ -765,6 +848,15 @@ static int send_chunk_with_removal(Client* client, Chunk* chunk, Config* config,
     File* f = chunk->items[i];
     if (f == NULL)
       continue;
+    if (f->is_dir) {
+      /* Explicit directory entry (--dirs): a MKDIR frame carrying only the
+         destination path.  Directories have no source to remove and no
+         incremental check. */
+      if (!send_directory_entry(client, f))
+        return -1;
+      change_emit_dir_sent(config, f);
+      continue;
+    }
     bool stream = f->data->data == NULL && f->data->size > 0;
     bool use_sendfile =
         (config->use_sendfile && !config->use_compression) || (stream && !config->use_compression);
@@ -880,6 +972,9 @@ static int send_chunks_multithreaded(void* pipeline_context) {
   }
 }
 
+/* Scan thread of the -m pipeline.  --dirs disables recursive traversal (the
+   transfer is a small set of explicit directory/file entries), so it uses the
+   sequential scanner rather than spawning worker threads. */
 static int scan_directory_multithreaded(void* pipeline_context) {
   PipelineContextSender* context = (PipelineContextSender*)pipeline_context;
   protocol_session_bind(&context->allocation_session);
@@ -889,29 +984,42 @@ static int scan_directory_multithreaded(void* pipeline_context) {
     protocol_session_unbind();
     return thrd_error;
   }
-  ParallelScanner* scanner = parallel_scanner_create_with_options(
-      context->config->send_directory, &prepared.options, &context->allocation_session);
-
-  Chunk* current_chunk;
-  if (scanner == NULL) {
-    log_message(LOG_LEVEL_ERROR, "Failed to create parallel scanner");
+  bool dirs_mode = prepared.options.dirs;
+  DirectoryScanner* dscanner = NULL;
+  ParallelScanner* scanner = NULL;
+  if (dirs_mode) {
+    dscanner =
+        directory_scanner_create_with_options(context->config->send_directory, &prepared.options);
+  } else {
+    scanner = parallel_scanner_create_with_options(context->config->send_directory,
+                                                   &prepared.options, &context->allocation_session);
+  }
+  if (dscanner == NULL && scanner == NULL) {
+    log_message(LOG_LEVEL_ERROR, "Failed to create scanner");
     pipeline_cancel(context);
     prepared_scanner_destroy(&prepared);
     protocol_session_unbind();
     return thrd_error;
   }
-  while ((current_chunk = parallel_scanner_next(scanner)) != NULL) {
+  bool failed = false;
+  Chunk* current_chunk;
+  while (1) {
+    if (dirs_mode)
+      current_chunk = directory_scanner_next(dscanner);
+    else
+      current_chunk = parallel_scanner_next(scanner);
+    if (current_chunk == NULL) {
+      failed = dirs_mode ? directory_scanner_failed(dscanner) : parallel_scanner_failed(scanner);
+      break;
+    }
     if (context->config->use_delete) {
       mtx_lock(&context->mutex_scanner);
       bool manifest_ok = add_chunk_to_manifest(context->manifest, current_chunk);
       mtx_unlock(&context->mutex_scanner);
       if (!manifest_ok) {
-        pipeline_cancel(context);
+        failed = true;
         chunk_destroy(current_chunk);
-        parallel_scanner_destroy(scanner);
-        prepared_scanner_destroy(&prepared);
-        protocol_session_unbind();
-        return thrd_error;
+        break;
       }
     }
     if (!queue_enqueue_multithreaded_cancel(
@@ -919,15 +1027,15 @@ static int scan_directory_multithreaded(void* pipeline_context) {
             &context->condition_not_empty_scanner, &context->condition_not_full_scanner,
             &context->cancelled)) {
       chunk_destroy(current_chunk);
-      pipeline_cancel(context);
-      parallel_scanner_destroy(scanner);
-      prepared_scanner_destroy(&prepared);
-      protocol_session_unbind();
-      return thrd_error;
+      failed = true;
+      break;
     }
   }
-  if (parallel_scanner_failed(scanner)) {
+  if (dirs_mode)
+    directory_scanner_destroy(dscanner);
+  else
     parallel_scanner_destroy(scanner);
+  if (failed) {
     prepared_scanner_destroy(&prepared);
     mtx_lock(&context->mutex_scanner);
     context->scanner_done = true;
@@ -943,7 +1051,6 @@ static int scan_directory_multithreaded(void* pipeline_context) {
   cnd_signal(&context->condition_not_empty_scanner);
   mtx_unlock(&context->mutex_scanner);
 
-  parallel_scanner_destroy(scanner);
   prepared_scanner_destroy(&prepared);
   protocol_session_unbind();
   return thrd_success;

src/client/scanner.c

@@ -306,6 +306,12 @@ DirectoryScanner* directory_scanner_create_with_options(const char* root_directo
   scanner->file_list = options->file_list;
   scanner->base_filters = options->base_filters;
   scanner->per_dir_filters = options->per_dir_filters;
+  scanner->dirs_mode = options->dirs;
+  scanner->relative_mode = options->relative && options->file_list != NULL;
+  scanner->dirs_root_emitted = false;
+  scanner->list_index = 0;
+  scanner->dirs_batch = NULL;
+  scanner->dirs_batch_size = 0;
   scanner->filter_nodes = NULL;
   if (scanner->base_filters || scanner->per_dir_filters) {
     scanner->filter_nodes = array_list_create(filter_node_destroy);
@@ -372,6 +378,8 @@ DirectoryScanner* directory_scanner_create(const char* root_directory, bool use_
                             false,
                             NULL,
                             NULL,
+                            false,
+                            false,
                             false};
   return directory_scanner_create_with_options(root_directory, &options);
 }
@@ -387,6 +395,7 @@ void directory_scanner_destroy(DirectoryScanner* scanner) {
   free(scanner->current_rel);
   free(scanner->root_path);
   array_list_delete(scanner->filter_nodes);
+  array_list_delete(scanner->dirs_batch);
   queue_destroy(scanner->directories);
   free(scanner);
 }
@@ -448,7 +457,174 @@ static int open_next_directory(DirectoryScanner* scanner) {
   return 1;
 }
 
+/* ---- --dirs mode ----
+   With -d the scanner transfers directory entries and never recurses into
+   contents.  A plain `-d <dir>` sends only the source-root directory mirror
+   (created empty at the destination).  With -d + --files-from exactly the
+   listed items are sent: listed directories become empty directory entries and
+   listed regular files are transferred as files; nothing else is scanned, so
+   no descent into a listed directory can happen. */
+
+/* Build the File for the transfer root directory itself (the `-d <dir>` and
+ * "." cases). */
+static File* dirs_root_dir_file(DirectoryScanner* scanner) {
+  struct stat st;
+  if (stat(scanner->root_path, &st) != 0 || !S_ISDIR(st.st_mode)) {
+    log_perror("Could not stat source directory");
+    scanner->failed = true;
+    return NULL;
+  }
+  File* file = file_create(scanner->root_path);
+  if (!file) {
+    scanner->failed = true;
+    return NULL;
+  }
+  file->is_dir = true;
+  if (scanner->use_metadata) {
+    file->metadata = file_metadata_create(&st);
+    if (!file->metadata) {
+      file_destroy(file);
+      scanner->failed = true;
+      return NULL;
+    }
+  }
+  return file;
+}
+
+/* Map one normalized --files-from entry to a File (a directory entry or a
+ * regular file to transfer), or NULL to skip the entry. */
+static File* dirs_file_for_entry(DirectoryScanner* scanner, const char* entry) {
+  if (entry[0] == '\0') {
+    /* "." (whole tree): under -R the bare receive root is the destination and
+       there is nothing to create for the root itself; otherwise mirror the
+       source-root directory (empty). */
+    if (scanner->relative_mode)
+      return NULL;
+    return dirs_root_dir_file(scanner);
+  }
+  char* abs_path = path_cat(scanner->root_path, entry);
+  if (!abs_path) {
+    scanner->failed = true;
+    return NULL;
+  }
+  struct stat link_stats;
+  if (lstat(abs_path, &link_stats) != 0) {
+    log_message(LOG_LEVEL_ERROR, "--dirs listed entry is not present under the source: %s", entry);
+    free(abs_path);
+    scanner->failed = true;
+    return NULL;
+  }
+  struct stat effective = link_stats;
+  if (S_ISLNK(link_stats.st_mode)) {
+    /* A symlink is transferred (following its referent) only when a link
+       resolution option is active, mirroring the regular scanner. */
+    bool resolve = scanner->follow_symlinks || scanner->copy_links || scanner->safe_links ||
+                   scanner->copy_unsafe_links;
+    if (!resolve || stat(abs_path, &effective) != 0) {
+      free(abs_path);
+      return NULL;
+    }
+  }
+  bool is_dir = S_ISDIR(effective.st_mode);
+  bool is_file = S_ISREG(effective.st_mode);
+  if (!is_dir && !is_file) {
+    free(abs_path);
+    return NULL;
+  }
+  File* file = file_create(abs_path);
+  free(abs_path);
+  if (!file) {
+    scanner->failed = true;
+    return NULL;
+  }
+  file->is_dir = is_dir;
+  file->data->size = is_file ? (unsigned long long)effective.st_size : 0;
+  if (scanner->relative_mode) {
+    file->send_path = str_dup(entry);
+    if (!file->send_path) {
+      file_destroy(file);
+      scanner->failed = true;
+      return NULL;
+    }
+  }
+  if (scanner->use_metadata) {
+    file->metadata = file_metadata_create(&effective);
+    if (!file->metadata) {
+      file_destroy(file);
+      scanner->failed = true;
+      return NULL;
+    }
+  }
+  return file;
+}
+
+/* The next File from the --dirs generator, or NULL when exhausted. */
+static File* dirs_next_file(DirectoryScanner* scanner) {
+  if (!scanner->file_list) {
+    if (scanner->dirs_root_emitted)
+      return NULL;
+    scanner->dirs_root_emitted = true;
+    return dirs_root_dir_file(scanner);
+  }
+  while (scanner->list_index < scanner->file_list->count) {
+    const char* entry = scanner->file_list->entries[scanner->list_index++];
+    File* file = dirs_file_for_entry(scanner, entry);
+    if (scanner->failed)
+      return NULL;
+    if (file)
+      return file;
+  }
+  return NULL;
+}
+
+static Chunk* dirs_flush_batch(DirectoryScanner* scanner) {
+  if (!scanner->dirs_batch || scanner->dirs_batch->size == 0) {
+    array_list_delete(scanner->dirs_batch);
+    scanner->dirs_batch = NULL;
+    scanner->dirs_batch_size = 0;
+    return NULL;
+  }
+  ArrayList* batch = scanner->dirs_batch;
+  scanner->dirs_batch = NULL;
+  scanner->dirs_batch_size = 0;
+  Chunk* chunk = chunk_data_to_chunk(batch);
+  if (!chunk)
+    scanner->failed = true;
+  return chunk;
+}
+
+static Chunk* directory_scanner_next_dirs(DirectoryScanner* scanner) {
+  while (scanner->dirs_batch == NULL || scanner->dirs_batch_size <= scanner->chunk_size) {
+    if (!scanner->dirs_batch) {
+      scanner->dirs_batch = array_list_create(file_destroy);
+      if (!scanner->dirs_batch) {
+        scanner->failed = true;
+        return NULL;
+      }
+      scanner->dirs_batch_size = 0;
+    }
+    File* file = dirs_next_file(scanner);
+    if (scanner->failed) {
+      dirs_flush_batch(scanner);
+      return NULL;
+    }
+    if (!file) {
+      return dirs_flush_batch(scanner);
+    }
+    if (!array_list_add(scanner->dirs_batch, file)) {
+      file_destroy(file);
+      scanner->failed = true;
+      dirs_flush_batch(scanner);
+      return NULL;
+    }
+    scanner->dirs_batch_size += file->data ? file->data->size : 0;
+  }
+  return dirs_flush_batch(scanner);
+}
+
 Chunk* directory_scanner_next(DirectoryScanner* scanner) {
+  if (scanner && scanner->dirs_mode)
+    return directory_scanner_next_dirs(scanner);
   ArrayList* chunk_data = array_list_create(file_destroy);
   if (!chunk_data) {
     scanner->failed = true;
@@ -477,16 +653,27 @@ Chunk* directory_scanner_next(DirectoryScanner* scanner) {
     if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
       continue;
 
-    ScannerOptions options = {scanner->use_metadata,     scanner->chunk_size,
-                              scanner->exclude_patterns, scanner->exclude_count,
-                              scanner->include_patterns, scanner->include_count,
-                              scanner->max_size,         scanner->min_size,
-                              scanner->max_depth,        0,
-                              scanner->follow_symlinks,  scanner->copy_links,
-                              scanner->safe_links,       scanner->copy_unsafe_links,
-                              scanner->checksum,         scanner->one_file_system,
-                              scanner->file_list,        scanner->base_filters,
-                              scanner->per_dir_filters};
+    ScannerOptions options = {scanner->use_metadata,
+                              scanner->chunk_size,
+                              scanner->exclude_patterns,
+                              scanner->exclude_count,
+                              scanner->include_patterns,
+                              scanner->include_count,
+                              scanner->max_size,
+                              scanner->min_size,
+                              scanner->max_depth,
+                              0,
+                              scanner->follow_symlinks,
+                              scanner->copy_links,
+                              scanner->safe_links,
+                              scanner->copy_unsafe_links,
+                              scanner->checksum,
+                              scanner->one_file_system,
+                              scanner->file_list,
+                              scanner->base_filters,
+                              scanner->per_dir_filters,
+                              false,
+                              false};
     ScannerEntry inspected;
     int inspection = scanner_inspect_entry(&options, scanner->current_path, scanner->current_path,
                                            entry->d_name, &inspected);
@@ -511,13 +698,23 @@ Chunk* directory_scanner_next(DirectoryScanner* scanner) {
     bool passes_selection =
         entry_passes_selection(scanner->file_list, scanner->base_filters, scanner->current_node,
                                rel, entry->d_name, is_dir, scanner->per_dir_filters);
+    /* With -R + --files-from the wire/destination path is the entry's bare
+       relative path; keep `rel` alive to attach it to a transferred file. */
+    char* rel_copy = scanner->relative_mode ? str_dup(rel) : NULL;
     free(rel);
+    if (rel_copy == NULL && scanner->relative_mode) {
+      free(cur_path);
+      scanner->failed = true;
+      break;
+    }
     if (!passes_selection) {
+      free(rel_copy);
       free(cur_path);
       continue;
     }
 
     if (is_dir) {
+      free(rel_copy);
       if (!scanner_same_filesystem(scanner->one_file_system, scanner->root_dev, stats.st_dev)) {
         free(cur_path);
         continue;
@@ -533,38 +730,45 @@ Chunk* directory_scanner_next(DirectoryScanner* scanner) {
       free(cur_path);
     } else {
       if (scanner->max_depth > 0 && scanner->current_depth + 1 > scanner->max_depth) {
+        free(rel_copy);
         free(cur_path);
         continue;
       }
       File* file = file_create(cur_path);
+      free(cur_path);
       if (file == NULL) {
-        free(cur_path);
+        free(rel_copy);
         scanner->failed = true;
         continue;
       }
       file->data->size = stats.st_size;
+      if (scanner->relative_mode) {
+        file->send_path = rel_copy;
+        rel_copy = NULL;
+      }
       if (scanner->use_metadata)
         file->metadata = file_metadata_create(&stats);
       if (scanner->use_metadata && !file->metadata) {
+        free(rel_copy);
         file_destroy(file);
-        free(cur_path);
         scanner->failed = true;
         break;
       }
       if (!array_list_add(chunk_data, file)) {
+        free(rel_copy);
         file_destroy(file);
         scanner->failed = true;
         break;
       }
       chunk_data_size += file->data->size;
       if (chunk_data_size > scanner->chunk_size) {
-        free(cur_path);
+        free(rel_copy);
         Chunk* result = chunk_data_to_chunk(chunk_data);
         if (!result)
           scanner->failed = true;
         return result;
       }
-      free(cur_path);
+      free(rel_copy);
     }
   }
 
@@ -792,12 +996,15 @@ static void scan_root_entry(const ScannerOptions* options, const FilterNode* roo
   }
   bool passes = entry_passes_selection(options->file_list, options->base_filters, root_node, rel,
                                        entry->d_name, is_dir, options->per_dir_filters);
-  free(rel);
+  /* -R + --files-from: root-level files keep their bare relative send path. */
+  bool use_rel = options->relative && options->file_list != NULL;
   if (!passes) {
+    free(rel);
     free(cur_path);
     return;
   }
   if (is_dir) {
+    free(rel);
     if (!scanner_same_filesystem(options->one_file_system, root_dev, st.st_dev)) {
       free(cur_path);
       return;
@@ -811,18 +1018,25 @@ static void scan_root_entry(const ScannerOptions* options, const FilterNode* roo
   File* file = file_create(cur_path);
   free(cur_path);
   if (!file) {
+    free(rel);
     ps->failed = true;
     return;
   }
   file->data->size = st.st_size;
+  if (use_rel) {
+    file->send_path = rel;
+    rel = NULL;
+  }
   if (options->use_metadata)
     file->metadata = file_metadata_create(&st);
   if (options->use_metadata && !file->metadata) {
+    free(rel);
     file_destroy(file);
     ps->failed = true;
     return;
   }
   if (!array_list_add(root_files, file)) {
+    free(rel);
     file_destroy(file);
     ps->failed = true;
   }

src/client/scanner.h

@@ -35,6 +35,8 @@ typedef struct {
   const FileListSet* file_list;       /* --files-from allow-set, or NULL */
   const FilterRuleList* base_filters; /* command-line + -C rules, or NULL */
   bool per_dir_filters;               /* -F: read .rsync-filter per directory */
+  bool dirs;                          /* -d/--dirs: transfer dir entries, no recursion */
+  bool relative;                      /* -R/--relative (dest rel paths, with --files-from) */
 } ScannerOptions;
 
 /* Internal per-scanner filter state. FilterNode chains represent the ordered
@@ -73,6 +75,14 @@ typedef struct {
   const FileListSet* file_list;
   const FilterRuleList* base_filters;
   bool per_dir_filters;
+  /* --dirs / -R state for the directory-entry generator (dirs_mode replaces
+     the recursive scan). */
+  bool dirs_mode;
+  bool relative_mode; /* file_list && relative: send bare relative wire paths */
+  bool dirs_root_emitted;
+  int list_index;
+  ArrayList* dirs_batch; /* owned when non-NULL */
+  unsigned long long dirs_batch_size;
 } DirectoryScanner;
 
 typedef struct {

src/client/usage.c

@@ -26,8 +26,17 @@ void print_usage(void) {
   printf("  --delete            Delete files on receiver not in source\n");
   printf("  --ignore-existing  Skip files that already exist on receiver\n");
   printf("  --delay-updates    Put updated files into place only at the end of transfer\n");
-  printf(
-      "  --dirs, --old-dirs, --old-d  Transfer directories without recursing (not implemented)\n");
+  printf("  --dirs, -d, --old-dirs, --old-d  Transfer the named directory entries without\n");
+  printf("                    recursing into their contents (-d <dir> mirrors the source\n");
+  printf("                    directory empty; with --files-from listed dirs are created\n");
+  printf("                    empty and listed files are transferred)\n");
+  printf("  -R, --relative    With --files-from, preserve each listed entry's relative path\n");
+  printf("                    below the destination root instead of mirroring the full\n");
+  printf("                    source path (no effect without --files-from)\n");
+  printf("  --no-implied-dirs  With -R --files-from, refuse to place a listed file whose\n");
+  printf("                    parent directory is not itself listed\n");
+  printf("  --mkpath          Create the destination root directory on the server when it\n");
+  printf("                    does not exist yet\n");
   printf("  --del               Alias for --delete-during (not implemented)\n");
   printf("  --exclude <pattern> Exclude files matching pattern\n");
   printf("  --include <pattern> Only include files matching pattern\n");