Merge pull request 'docs: clarify rsync compatibility roadmap' (#215 ) from docs/rsync-compatible-readme-clean into dev

Reviewed-on: #215
Merge branch 'dev' into docs/rsync-compatible-readme-clean
2026-08-15 13:48:01 +02:00 · 2026-08-15 13:47:55 +02:00 · 2026-08-15 13:41:23 +02:00 · 2026-08-15 13:14:28 +02:00 · 2026-08-15 12:54:38 +02:00 · 2026-08-15 11:55:41 +02:00
31 changed files with 1369 additions and 1259 deletions
@@ -58,18 +58,15 @@ endif()
 find_package(OpenSSL REQUIRED)

 file(GLOB SHARED_SRCS "src/shared/*.c")
-set(FILE_STORE_SRCS src/shared/file_store.c)
-list(REMOVE_ITEM SHARED_SRCS ${FILE_STORE_SRCS})
 file(GLOB SERVER_SRCS "src/server/*.c")
-set(SERVER_RECEIVER_SRCS src/server/receiver.c)
 file(GLOB CLIENT_SRCS "src/client/*.c")

 # --- Main executables ---
-add_executable(server ${SERVER_SRCS} ${SHARED_SRCS} ${FILE_STORE_SRCS})
+add_executable(server ${SERVER_SRCS} ${SHARED_SRCS})
 target_include_directories(server PRIVATE src/shared src/server src/client)
 target_link_libraries(server PRIVATE Threads::Threads ${ZSTD_LIBRARY} OpenSSL::SSL OpenSSL::Crypto xxhash)

-add_executable(client ${CLIENT_SRCS} ${SHARED_SRCS} ${FILE_STORE_SRCS} ${SERVER_RECEIVER_SRCS})
+add_executable(client ${CLIENT_SRCS} ${SHARED_SRCS})
 target_include_directories(client PRIVATE src/shared src/server src/client)
 target_link_libraries(client PRIVATE Threads::Threads ${ZSTD_LIBRARY} OpenSSL::SSL OpenSSL::Crypto xxhash)

@@ -82,7 +79,7 @@ set(TEST_INCLUDES tests src/shared src/server src/client)

 # Monolithic test binary (backward compatible)
 file(GLOB TEST_SRCS "tests/test_*.c" "tests/runner.c")
-add_executable(tests ${TEST_SRCS} ${SHARED_SRCS} ${FILE_STORE_SRCS} ${SERVER_RECEIVER_SRCS} src/client/scanner.c src/client/client_cli.c src/client/client_validation.c src/client/usage.c)
+add_executable(tests ${TEST_SRCS} ${SHARED_SRCS} src/client/scanner.c src/client/client_cli.c)
 target_include_directories(tests PRIVATE ${TEST_INCLUDES})
 target_compile_definitions(tests PRIVATE FASTSYNC_TEST_BUILD)
 target_link_libraries(tests PRIVATE ${TEST_LIBS})
@@ -97,7 +94,7 @@ if(ENABLE_FUZZ)
  file(GLOB FUZZ_SRCS "tests/fuzz/*.c")
 	foreach(FUZZ_SRC ${FUZZ_SRCS})
 		get_filename_component(FUZZ_NAME ${FUZZ_SRC} NAME_WE)
-    add_executable(${FUZZ_NAME} ${FUZZ_SRC} ${SHARED_SRCS} ${FILE_STORE_SRCS} ${SERVER_RECEIVER_SRCS})
+		add_executable(${FUZZ_NAME} ${FUZZ_SRC} ${SHARED_SRCS})
 		target_include_directories(${FUZZ_NAME} PRIVATE ${TEST_INCLUDES})
 		target_compile_options(${FUZZ_NAME} PRIVATE -fsanitize=fuzzer,address,undefined -fno-omit-frame-pointer)
 		target_link_options(${FUZZ_NAME} PRIVATE -fsanitize=fuzzer,address,undefined)
@@ -45,7 +45,7 @@ replacement for every rsync feature or protocol mode.

 - Recursive directory scanning.
 - Rsync-style source and destination arguments.
- SSH transport using `user@host:/path` destinations.
+- SSH transport using `user@host:destination` paths below the remote authorized root.
 - TCP client/server transfers.
 - Dry runs, excludes, includes, size filters, backups, statistics, and
  bandwidth limiting.
@@ -79,8 +79,10 @@ partial, alternate, and planned behavior.

 ### Build

-Requirements: C11 compiler, CMake 3.22 or newer, zstd, OpenSSL, pthreads,
-and an SSH client for SSH transport.
+Requirements: C11 compiler, CMake 3.22 or newer, xxHash, zstd, OpenSSL,
+pthreads, and an SSH client for SSH transport. The first CMake configure fetches
+xxHash from GitHub, so network access is required unless the dependency is
+already cached.

 ```bash
 cmake -B build -S .
@@ -98,10 +100,12 @@ cmake --build build -j$(nproc)
 ### SSH transfer

 The remote host must have `fastsync-server` available in `PATH`, or use
-`--fastsync-server-path`.
+`--fastsync-server-path`. SSH starts `fastsync-server --stdio` in its remote
+working directory, so use a destination below that directory unless the
+remote server is otherwise configured with a matching authorized root.

 ```bash
-./build/client /path/to/source user@host:/path/to/destination
+./build/client /path/to/source user@host:destination
 ```

 ### TCP transfer
@@ -109,7 +113,7 @@ The remote host must have `fastsync-server` available in `PATH`, or use
 Start the FastSync server:

 ```bash
-./build/server -p 8080
+./build/server --destination-root /path/to -p 8080
 ```

 Then run the client:
@@ -123,7 +127,7 @@ Then run the client:
 ### TLS transfer

 ```bash
-./build/server --tls --cert server.pem --key server-key.pem -p 8443
+./build/server --destination-root /path/to --tls --cert server.pem --key server-key.pem -p 8443
 ./build/client --tls --cert client.pem --key client-key.pem --ca ca.pem \
  --server-host example.com --server-port 8443 \
  --source-dir /path/to/source --dest-dir /path/to/destination \
@@ -140,30 +144,30 @@ FastSync-native are optional performance or transport extensions.
 ./build/client /source/ /destination/

 # Archive-style synchronization (current FastSync archive behavior)
-./build/client -a /source/ user@host:/destination/
+./build/client -a /source/ user@host:destination/

 # Preview a transfer without changing the destination
 ./build/client -n /source/ /destination/

 # Exclude temporary and object files
 ./build/client --exclude '*.tmp' --exclude '*.o' \
-  /source/ user@host:/destination/
+  /source/ user@host:destination/

 # Remove destination entries not present in the source
-./build/client --delete /source/ user@host:/destination/
+./build/client --delete /source/ user@host:destination/

 # Skip unchanged files using size and modification time
-./build/client --incremental /source/ user@host:/destination/
+./build/client --incremental /source/ user@host:destination/

 # Verify content when size and time are not sufficient
-./build/client --incremental --checksum /source/ user@host:/destination/
+./build/client --incremental --checksum /source/ user@host:destination/

 # Preserve supported mode and timestamp metadata
-./build/client -M /source/ user@host:/destination/
+./build/client -M /source/ user@host:destination/

 # Keep backups of overwritten destination files
-./build/client --backup --backup-dir /backups \
-  /source/ user@host:/destination/
+./build/client --backup --backup-dir backups \
+  /source/ user@host:destination/
 ```

 ## FastSync Extensions
@@ -217,8 +221,8 @@ before FastSync can claim full rsync CLI compatibility.
 | `--backup` | Back up overwritten files. |
 | `--backup-dir <dir>` | Store backups under a separate directory. |
 | `--suffix <suffix>` | Set the backup filename suffix. |
-| `--partial` | Keep received data under the configured partial location. Full resume semantics are planned. |
-| `--partial-dir <dir>` | Set the partial transfer directory. |
+| `--partial` | Select partial-transfer handling. With `--partial-dir`, completed files are written there; resumable transfers are not implemented. |
+| `--partial-dir <dir>` | Set a relative partial-transfer directory below the server destination root; use with `--partial`. |
 | `--inplace` | Write directly to the destination instead of using a temporary file. |

 ### Metadata and links
@@ -269,6 +273,7 @@ before FastSync can claim full rsync CLI compatibility.
 | `--cert <path>` | TLS certificate file. |
 | `--key <path>` | TLS private key file. |
 | `--ca <path>` | CA file for peer verification. |
+| `--destination-root <path>` | Confine received files to this server-side root; defaults to the current directory. |
 | `--allow-delete` | Permit client delete manifests. Deletion is refused by default. |
 | `-v`, `--verbose` | Enable debug logging. |
 | `--help` | Print server usage. |
@@ -152,14 +152,14 @@ This document maps rsync's full feature set to FastSync's current implementation

 | Flag | Rsync Description | FastSync Status | Notes |
 |------|-------------------|-----------------|-------|
-| `-S`, `--sparse` | Sparse block handling | ✅ Implemented | `preserve_sparse` config field |
+| `-S`, `--sparse` | Sparse block handling | ⚠️ Partial | Flag is accepted, but full hole preservation is not implemented |
 | `--preallocate` | Allocate dest files before writing | ❌ Not Implemented | |

 ## 11. Checksum & Comparison

 | Flag | Rsync Description | FastSync Status | Notes |
 |------|-------------------|-----------------|-------|
-| `--checksum` | Skip based on checksum | ❌ Not Implemented | Removed because it had no effect; `-c` means compression |
+| `--checksum` | Skip based on checksum | ✅ Implemented | With `--incremental`, compares xxHash64 content checksums; `-c` remains compression |
 | `--checksum-choice=STR` | Choose checksum algorithm | ❌ Not Implemented | xxHash used internally |
 | `--compare-dest=DIR` | Compare dest files relative to DIR | ❌ Not Implemented | Removed because it had no effect |
 | `--copy-dest=DIR` | Include copies of unchanged files | ❌ Not Implemented | Removed because it had no effect |
@@ -1,12 +1,10 @@
 #include "client_send.h"
-#include "client_validation.h"
 #include "config.h"
 #include "delta.h"
 #include "log.h"
 #include "protocol.h"
 #include "transport_tcp.h"
 #include "transport_tls.h"
-#include "usage.h"
 #include "utils.h"
 #include <errno.h>
 #include <limits.h>
@@ -14,6 +12,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include "usage.c"

 #ifndef FASTSYNC_TEST_BUILD
 /* Parse environment variables for source/destination directories and save-to-disk flag. */
@@ -361,6 +360,55 @@ int parse_args(Config* config, int argc, char* argv[], int* positional_args,
  return 0;
 }

+#ifndef FASTSYNC_TEST_BUILD
+/* Validate config after parsing. Returns true if valid. */
+static bool validate_config(const Config* config) {
+  if (!config->send_directory || !config->receive_root_directory) {
+    fprintf(stderr, "Error: source and destination directories are required\n");
+    print_usage();
+    return false;
+  }
+  if (config->use_sendfile && (config->use_chunk_serialization || config->use_compression)) {
+    fprintf(stderr, "Error: -f/--sendfile cannot be combined with -c (compression) or -s (chunk "
+                    "serialization)\n");
+    return false;
+  }
+  if (config->transport == TRANSPORT_SSH && config->use_sendfile) {
+    fprintf(stderr, "Error: -f/--sendfile is not supported with SSH transport\n");
+    return false;
+  }
+  if (config->use_incremental && config->use_chunk_serialization) {
+    fprintf(stderr, "Error: --incremental is not supported with -s (chunk serialization)\n");
+    return false;
+  }
+  if (config->use_delta && !config->use_incremental) {
+    fprintf(stderr, "Error: --delta requires --incremental\n");
+    return false;
+  }
+  if (config->use_delta && config->use_chunk_serialization) {
+    fprintf(stderr, "Error: --delta cannot be combined with -s (chunk serialization)\n");
+    return false;
+  }
+  if (config->use_delta && config->use_sendfile) {
+    fprintf(stderr, "Error: --delta cannot be combined with -f (sendfile)\n");
+    return false;
+  }
+  if (config->append || config->append_verify) {
+    fprintf(
+        stderr,
+        "Error: --append and --append-verify are not supported yet; refusing to ignore option\n");
+    return false;
+  }
+  if (config->use_tls) {
+    if (!config->tls_cert || !config->tls_key) {
+      fprintf(stderr, "Error: --tls requires --cert and --key\n");
+      return false;
+    }
+  }
+  return true;
+}
+#endif /* FASTSYNC_TEST_BUILD */
+
 static int read_patterns_from_file(const char* filepath, char*** patterns, int* count) {
  FILE* fp = fopen(filepath, "r");
  if (!fp) {
@@ -28,87 +28,6 @@
 /* Forward declaration for progress-reporting thread used in multithreaded send. */
 static int progress_thread_fn(void* arg);

-static ScannerOptions scanner_options_from_config(const Config* config, int num_threads) {
-  ScannerOptions options = {
-      config->use_metadata,  config->chunk_size,        config->exclude_patterns,
-      config->exclude_count, config->include_patterns,  config->include_count,
-      config->max_size,      config->min_size,          config->max_depth,
-      num_threads,           config->follow_symlinks,   config->copy_links,
-      config->safe_links,    config->copy_unsafe_links, config->checksum};
-  return options;
-}
-
-/* Select the configured transport for both transfer execution paths. */
-static Client* connect_transfer_client(const Config* config) {
-  if (config->transport == TRANSPORT_SSH) {
-    if (config->use_sendfile) {
-      fprintf(stderr, "Error: -f/--sendfile is not supported with SSH transport\n");
-      return NULL;
-    }
-    return client_connect_ssh(config->ssh_destination, config->ssh_port,
-                              config->fastsync_server_path);
-  }
-
-  Client* client = client_create();
-  if (!client)
-    return NULL;
-  bool connected;
-  if (config->use_tls) {
-    connected = client_connect_tls(client, config->server_host, config->server_port,
-                                   config->tls_cert, config->tls_key, config->tls_ca);
-  } else {
-    connected = client_connect(client, config->server_host, config->server_port);
-  }
-  if (!connected) {
-    client_delete(client);
-    return NULL;
-  }
-  return client;
-}
-
-static void disconnect_transfer_client(Client* client) {
-  if (!client)
-    return;
-  client_disconnect(client);
-  client_delete(client);
-}
-
-static ArrayList* create_transfer_manifest(const Config* config) {
-  return config->use_delete ? array_list_create(free) : NULL;
-}
-
-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;
-    if (*path == '/')
-      path++;
-    char* entry = str_dup(path);
-    if (!entry) {
-      log_message(LOG_LEVEL_ERROR, "Failed to allocate manifest entry");
-      return false;
-    }
-    if (!array_list_add(manifest, entry)) {
-      free(entry);
-      return false;
-    }
-  }
-  return true;
-}
-
-static bool finalize_transfer(Client* client) {
-  Status status;
-  return send_status(client->file_descriptor, STATUS_FINISHED) &&
-         receive_status(client->file_descriptor, &status) && status == STATUS_OK;
-}
-
-static void mark_sender_done(PipelineContextSender* context) {
-  mtx_lock(&context->mutex_progress);
-  context->sender_done = true;
-  mtx_unlock(&context->mutex_progress);
-}
-
 static void pipeline_cancel(PipelineContextSender* context) {
  mtx_lock(&context->mutex_scanner);
  mtx_lock(&context->mutex_loader);
@@ -124,10 +43,12 @@ static void pipeline_cancel(PipelineContextSender* context) {
 }

 /* Print dry-run manifest showing files that would be transferred. Returns 0 on success. */
-static int send_dry_run_manifest(const Config* config) {
-  ScannerOptions options = scanner_options_from_config(config, 0);
-  DirectoryScanner* scanner =
-      directory_scanner_create_with_options(config->send_directory, &options);
+static int send_dry_run_manifest(Config* config) {
+  DirectoryScanner* scanner = directory_scanner_create(
+      config->send_directory, config->use_metadata, config->chunk_size, config->exclude_patterns,
+      config->exclude_count, config->include_patterns, config->include_count, config->max_size,
+      config->min_size, config->max_depth, config->follow_symlinks, config->copy_links,
+      config->safe_links, config->copy_unsafe_links, config->checksum);
  if (!scanner)
    return -1;
  Chunk* chunk;
@@ -370,22 +291,49 @@ int send_chunk(Client* client, Chunk* chunk, Config* config) {

 static int send_chunks_multithreaded(void* pipeline_context) {
  PipelineContextSender* context = (PipelineContextSender*)pipeline_context;
-  Client* client = connect_transfer_client(context->config);
-  if (!client) {
-    if (context->config->transport == TRANSPORT_TCP)
-      fprintf(stderr, "Error: could not connect to server%s\n",
-              context->config->use_tls ? " via TLS" : "");
-    mark_sender_done(context);
-    return thrd_error;
+  Client* client;
+  if (context->config->transport == TRANSPORT_SSH) {
+    if (context->config->use_sendfile) {
+      fprintf(stderr, "Error: -f/--sendfile is not supported with SSH transport\n");
+      mtx_lock(&context->mutex_progress);
+      context->sender_done = true;
+      mtx_unlock(&context->mutex_progress);
+      return 1;
+    }
+    client = client_connect_ssh(context->config->ssh_destination, context->config->ssh_port,
+                                context->config->fastsync_server_path);
+  } else if (context->config->use_tls) {
+    client = client_create();
+    if (!client || !client_connect_tls(client, context->config->server_host,
+                                       context->config->server_port, context->config->tls_cert,
+                                       context->config->tls_key, context->config->tls_ca)) {
+      if (client)
+        client_delete(client);
+      fprintf(stderr, "Error: could not connect to server via TLS\n");
+      mtx_lock(&context->mutex_progress);
+      context->sender_done = true;
+      mtx_unlock(&context->mutex_progress);
+      return thrd_error;
+    }
+  } else {
+    client = client_create();
+    if (!client ||
+        !client_connect(client, context->config->server_host, context->config->server_port)) {
+      if (client)
+        client_delete(client);
+      fprintf(stderr, "Error: could not connect to server\n");
+      mtx_lock(&context->mutex_progress);
+      context->sender_done = true;
+      mtx_unlock(&context->mutex_progress);
+      return thrd_error;
+    }
  }
-  ProtocolSession session;
-  protocol_session_init(&session, client->file_descriptor, client->file_descriptor);
-  protocol_session_set_ssl(&session, (SSL*)client->ssl);
-  protocol_session_bind(&session);
  if (!config_send(client->file_descriptor, context->config)) {
-    disconnect_transfer_client(client);
-    mark_sender_done(context);
-    protocol_session_unbind();
+    client_disconnect(client);
+    client_delete(client);
+    mtx_lock(&context->mutex_progress);
+    context->sender_done = true;
+    mtx_unlock(&context->mutex_progress);
    return thrd_error;
  }

@@ -398,26 +346,35 @@ static int send_chunks_multithreaded(void* pipeline_context) {
        if (send_delete_manifest(client->file_descriptor, context->manifest) != 0)
          goto send_fail;
      }
-      bool ok = finalize_transfer(client);
-      disconnect_transfer_client(client);
-      mark_sender_done(context);
-      protocol_session_unbind();
+      if (!send_status(client->file_descriptor, STATUS_FINISHED))
+        goto send_fail;
+      Status s;
+      int ok = receive_status(client->file_descriptor, &s) && s == STATUS_OK;
+      client_disconnect(client);
+      client_delete(client);
+      mtx_lock(&context->mutex_progress);
+      context->sender_done = true;
+      mtx_unlock(&context->mutex_progress);
      return ok ? thrd_success : thrd_error;

    send_fail:
      pipeline_cancel(context);
-      disconnect_transfer_client(client);
-      mark_sender_done(context);
-      protocol_session_unbind();
+      client_disconnect(client);
+      client_delete(client);
+      mtx_lock(&context->mutex_progress);
+      context->sender_done = true;
+      mtx_unlock(&context->mutex_progress);
      return thrd_error;
    }
    if (send_chunk(client, current_chunk, context->config) != 0) {
      fprintf(stderr, "Error: unexpected error while sending chunk\n");
      chunk_destroy(current_chunk);
      pipeline_cancel(context);
-      disconnect_transfer_client(client);
-      mark_sender_done(context);
-      protocol_session_unbind();
+      client_disconnect(client);
+      client_delete(client);
+      mtx_lock(&context->mutex_progress);
+      context->sender_done = true;
+      mtx_unlock(&context->mutex_progress);
      return thrd_error;
    }
    if (context->config->show_progress) {
@@ -436,9 +393,13 @@ static int send_chunks_multithreaded(void* pipeline_context) {

 static int scan_directory_multithreaded(void* pipeline_context) {
  PipelineContextSender* context = (PipelineContextSender*)pipeline_context;
-  ScannerOptions options = scanner_options_from_config(context->config, 4);
-  ParallelScanner* scanner =
-      parallel_scanner_create_with_options(context->config->send_directory, &options);
+  ParallelScanner* scanner = parallel_scanner_create(
+      context->config->send_directory, context->config->use_metadata, context->config->chunk_size,
+      context->config->exclude_patterns, context->config->exclude_count,
+      context->config->include_patterns, context->config->include_count, context->config->max_size,
+      context->config->min_size, context->config->max_depth, 4, context->config->follow_symlinks,
+      context->config->copy_links, context->config->safe_links, context->config->copy_unsafe_links,
+      context->config->checksum);

  Chunk* current_chunk;
  if (scanner == NULL) {
@@ -449,14 +410,28 @@ static int scan_directory_multithreaded(void* pipeline_context) {
  while ((current_chunk = parallel_scanner_next(scanner)) != NULL) {
    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);
-        chunk_destroy(current_chunk);
-        parallel_scanner_destroy(scanner);
-        return thrd_error;
+      for (int i = 0; i < current_chunk->element_count; i++) {
+        const char* p = current_chunk->items[i]->path;
+        if (*p == '/')
+          p++;
+        char* manifest_entry = str_dup(p);
+        if (!manifest_entry) {
+          log_message(LOG_LEVEL_ERROR, "Failed to allocate manifest entry");
+          mtx_unlock(&context->mutex_scanner);
+          pipeline_cancel(context);
+          parallel_scanner_destroy(scanner);
+          return thrd_error;
+        }
+        if (!array_list_add(context->manifest, manifest_entry)) {
+          free(manifest_entry);
+          mtx_unlock(&context->mutex_scanner);
+          pipeline_cancel(context);
+          chunk_destroy(current_chunk);
+          parallel_scanner_destroy(scanner);
+          return thrd_error;
+        }
      }
+      mtx_unlock(&context->mutex_scanner);
    }
    if (!queue_enqueue_multithreaded_cancel(
            context->queue_scanner, current_chunk, &context->mutex_scanner,
@@ -565,37 +540,61 @@ int send_files(Config* config) {
  if (config->dry_run)
    return send_dry_run_manifest(config);

-  Client* client = connect_transfer_client(config);
-  if (!client) {
-    if (config->transport == TRANSPORT_TCP)
-      fprintf(stderr, "Error: could not connect to server%s\n", config->use_tls ? " via TLS" : "");
-    return 1;
+  Client* client;
+  if (config->transport == TRANSPORT_SSH) {
+    if (config->use_sendfile) {
+      fprintf(stderr, "Error: -f/--sendfile is not supported with SSH transport\n");
+      return 1;
+    }
+    client =
+        client_connect_ssh(config->ssh_destination, config->ssh_port, config->fastsync_server_path);
+    if (!client)
+      return 1;
+  } else if (config->use_tls) {
+    client = client_create();
+    if (!client || !client_connect_tls(client, config->server_host, config->server_port,
+                                       config->tls_cert, config->tls_key, config->tls_ca)) {
+      if (client) {
+        client_disconnect(client);
+        client_delete(client);
+      }
+      fprintf(stderr, "Error: could not connect to server via TLS\n");
+      return 1;
+    }
+  } else {
+    client = client_create();
+    if (!client || !client_connect(client, config->server_host, config->server_port)) {
+      if (client) {
+        client_disconnect(client);
+        client_delete(client);
+      }
+      fprintf(stderr, "Error: could not connect to server\n");
+      return 1;
+    }
  }
-  ProtocolSession session;
-  protocol_session_init(&session, client->file_descriptor, client->file_descriptor);
-  protocol_session_set_ssl(&session, (SSL*)client->ssl);
-  protocol_session_bind(&session);
  if (!config_send(client->file_descriptor, config)) {
-    disconnect_transfer_client(client);
-    protocol_session_unbind();
+    client_disconnect(client);
+    client_delete(client);
    return 1;
  }
-  ScannerOptions scanner_options = scanner_options_from_config(config, 0);
-  DirectoryScanner* scanner =
-      directory_scanner_create_with_options(config->send_directory, &scanner_options);
+  DirectoryScanner* scanner = directory_scanner_create(
+      config->send_directory, config->use_metadata, config->chunk_size, config->exclude_patterns,
+      config->exclude_count, config->include_patterns, config->include_count, config->max_size,
+      config->min_size, config->max_depth, config->follow_symlinks, config->copy_links,
+      config->safe_links, config->copy_unsafe_links, config->checksum);
  Chunk* current_chunk;
  unsigned long long total_bytes = 0;
  int total_files = 0;
  time_t last_progress = 0;
  time_t start = time(NULL);
-  ArrayList* manifest = create_transfer_manifest(config);
+  ArrayList* manifest = config->use_delete ? array_list_create(free) : NULL;
  if (!scanner || (config->use_delete && !manifest)) {
    if (scanner)
      directory_scanner_destroy(scanner);
    if (manifest)
      array_list_delete(manifest);
-    disconnect_transfer_client(client);
-    protocol_session_unbind();
+    client_disconnect(client);
+    client_delete(client);
    return 1;
  }
  while ((current_chunk = directory_scanner_next(scanner)) != NULL) {
@@ -603,10 +602,30 @@ int send_files(Config* config) {
    for (int i = 0; i < current_chunk->element_count; i++) {
      chunk_bytes += current_chunk->items[i]->data->size;
      total_files++;
-    }
-    if (!add_chunk_to_manifest(manifest, current_chunk)) {
-      chunk_destroy(current_chunk);
-      goto send_fail;
+      if (manifest) {
+        const char* p = current_chunk->items[i]->path;
+        if (*p == '/')
+          p++;
+        char* manifest_entry = str_dup(p);
+        if (!manifest_entry) {
+          log_message(LOG_LEVEL_ERROR, "Failed to allocate manifest entry");
+          chunk_destroy(current_chunk);
+          array_list_delete(manifest);
+          directory_scanner_destroy(scanner);
+          client_disconnect(client);
+          client_delete(client);
+          return 1;
+        }
+        if (!array_list_add(manifest, manifest_entry)) {
+          free(manifest_entry);
+          chunk_destroy(current_chunk);
+          array_list_delete(manifest);
+          directory_scanner_destroy(scanner);
+          client_disconnect(client);
+          client_delete(client);
+          return 1;
+        }
+      }
    }
    if (!config->use_sendfile) {
      for (int i = 0; i < current_chunk->element_count; i++) {
@@ -650,7 +669,10 @@ int send_files(Config* config) {
    array_list_delete(manifest);
    manifest = NULL;
  }
-  bool ok = finalize_transfer(client);
+  if (!send_status(client->file_descriptor, STATUS_FINISHED))
+    goto send_fail;
+  Status s;
+  int ok = receive_status(client->file_descriptor, &s) && s == STATUS_OK;
  double elapsed_total = difftime(time(NULL), start);
  if (config->show_progress) {
    double rate = elapsed_total > 0 ? total_bytes / (1048576.0 * elapsed_total) : 0;
@@ -662,16 +684,16 @@ int send_files(Config* config) {
            rate);
  }
  directory_scanner_destroy(scanner);
-  disconnect_transfer_client(client);
-  protocol_session_unbind();
+  client_disconnect(client);
+  client_delete(client);
  return ok ? 0 : 1;

 send_fail:
  if (manifest)
    array_list_delete(manifest);
  directory_scanner_destroy(scanner);
-  disconnect_transfer_client(client);
-  protocol_session_unbind();
+  client_disconnect(client);
+  client_delete(client);
  return 1;
 }

@@ -707,7 +729,7 @@ int send_files_multithreaded(Config* config) {
    return 1;
  }
  if (config->use_delete)
-    context->manifest = create_transfer_manifest(config);
+    context->manifest = array_list_create(free);

  thrd_t scanner, loader, sender;
  bool scanner_created = false;
@@ -1,50 +0,0 @@
-#include "client_validation.h"
-#include "usage.h"
-#include <stdio.h>
-
-/* Validate config after parsing. Returns true if valid. */
-bool validate_config(const Config* config) {
-  if (!config->send_directory || !config->receive_root_directory) {
-    fprintf(stderr, "Error: source and destination directories are required\n");
-    print_usage();
-    return false;
-  }
-  if (config->use_sendfile && (config->use_chunk_serialization || config->use_compression)) {
-    fprintf(stderr, "Error: -f/--sendfile cannot be combined with -c (compression) or -s (chunk "
-                    "serialization)\n");
-    return false;
-  }
-  if (config->transport == TRANSPORT_SSH && config->use_sendfile) {
-    fprintf(stderr, "Error: -f/--sendfile is not supported with SSH transport\n");
-    return false;
-  }
-  if (config->use_incremental && config->use_chunk_serialization) {
-    fprintf(stderr, "Error: --incremental is not supported with -s (chunk serialization)\n");
-    return false;
-  }
-  if (config->use_delta && !config->use_incremental) {
-    fprintf(stderr, "Error: --delta requires --incremental\n");
-    return false;
-  }
-  if (config->use_delta && config->use_chunk_serialization) {
-    fprintf(stderr, "Error: --delta cannot be combined with -s (chunk serialization)\n");
-    return false;
-  }
-  if (config->use_delta && config->use_sendfile) {
-    fprintf(stderr, "Error: --delta cannot be combined with -f (sendfile)\n");
-    return false;
-  }
-  if (config->append || config->append_verify) {
-    fprintf(
-        stderr,
-        "Error: --append and --append-verify are not supported yet; refusing to ignore option\n");
-    return false;
-  }
-  if (config->use_tls) {
-    if (!config->tls_cert || !config->tls_key) {
-      fprintf(stderr, "Error: --tls requires --cert and --key\n");
-      return false;
-    }
-  }
-  return true;
-}
@@ -1,9 +0,0 @@
-#ifndef CLIENT_VALIDATION_H
-#define CLIENT_VALIDATION_H
-
-#include "config.h"
-#include <stdbool.h>
-
-bool validate_config(const Config* config);
-
-#endif
@@ -52,84 +52,13 @@ static bool safe_relative_link(const char* source_root, const char* containing_d
  return safe;
 }

-typedef struct {
-  char* path;
-  struct stat stats;
-  bool is_directory;
-} ScannerEntry;
-
-/* Inspect symlinks, resolve the entry type, and apply file filters once for both scanners. */
-static int scanner_inspect_entry(const ScannerOptions* options, const char* source_root,
-                                 const char* containing_dir, const char* name,
-                                 ScannerEntry* entry) {
-  entry->path = path_cat(containing_dir, name);
-  if (!entry->path)
-    return -1;
-
-  struct stat link_stats;
-  if (lstat(entry->path, &link_stats) != 0) {
-    free(entry->path);
-    return 0;
-  }
-  bool is_symlink = S_ISLNK(link_stats.st_mode);
-  if (is_symlink && !options->follow_symlinks && !options->copy_links && !options->safe_links &&
-      !options->copy_unsafe_links)
-    goto skip;
-
-  if (is_symlink && options->safe_links) {
-    char link_target[4096];
-    ssize_t length = readlink(entry->path, link_target, sizeof(link_target) - 1);
-    if (length < 0)
-      goto skip;
-    link_target[length] = '\0';
-    if (link_target[0] == '/' || !safe_relative_link(source_root, containing_dir, link_target))
-      goto skip;
-  }
-
-  if (is_symlink && options->copy_unsafe_links && !options->copy_links) {
-    char link_target[4096];
-    ssize_t length = readlink(entry->path, link_target, sizeof(link_target) - 1);
-    if (length < 0)
-      goto skip;
-    link_target[length] = '\0';
-    if (link_target[0] != '/')
-      goto skip;
-  }
-
-  if (is_symlink && options->follow_symlinks && !options->copy_links)
-    entry->stats = link_stats;
-  else if (stat(entry->path, &entry->stats) != 0)
-    goto skip;
-
-  entry->is_directory = S_ISDIR(entry->stats.st_mode);
-  if (entry->is_directory)
-    return 1;
-  for (int i = 0; i < options->exclude_count; i++)
-    if (glob_match(options->exclude_patterns[i], name))
-      goto skip;
-  if (options->include_count > 0) {
-    bool included = false;
-    for (int i = 0; i < options->include_count; i++)
-      if (glob_match(options->include_patterns[i], name))
-        included = true;
-    if (!included)
-      goto skip;
-  }
-  if ((options->max_size > 0 && (unsigned long long)entry->stats.st_size > options->max_size) ||
-      (options->min_size > 0 && (unsigned long long)entry->stats.st_size < options->min_size))
-    goto skip;
-  return 1;
-
-skip:
-  free(entry->path);
-  entry->path = NULL;
-  return 0;
-}
-
-DirectoryScanner* directory_scanner_create_with_options(const char* root_directory,
-                                                        const ScannerOptions* options) {
-  if (!root_directory || !options)
-    return NULL;
+DirectoryScanner* directory_scanner_create(const char* root_directory, bool use_metadata,
+                                           unsigned long long chunk_size, char** exclude_patterns,
+                                           int exclude_count, char** include_patterns,
+                                           int include_count, unsigned long long max_size,
+                                           unsigned long long min_size, int max_depth,
+                                           bool follow_symlinks, bool copy_links, bool safe_links,
+                                           bool copy_unsafe_links, bool checksum) {
  DirectoryScanner* scanner = calloc(1, sizeof(DirectoryScanner));
  if (scanner == NULL)
    return NULL;
@@ -140,21 +69,21 @@ DirectoryScanner* directory_scanner_create_with_options(const char* root_directo
  }
  scanner->current_dir = NULL;
  scanner->current_path = NULL;
-  scanner->use_metadata = options->use_metadata;
-  scanner->chunk_size = options->chunk_size > 0 ? options->chunk_size : DESIRED_CHUNK_SIZE;
-  scanner->exclude_patterns = options->exclude_patterns;
-  scanner->exclude_count = options->exclude_count;
-  scanner->include_patterns = options->include_patterns;
-  scanner->include_count = options->include_count;
-  scanner->max_size = options->max_size;
-  scanner->min_size = options->min_size;
-  scanner->max_depth = options->max_depth;
+  scanner->use_metadata = use_metadata;
+  scanner->chunk_size = chunk_size > 0 ? chunk_size : DESIRED_CHUNK_SIZE;
+  scanner->exclude_patterns = exclude_patterns;
+  scanner->exclude_count = exclude_count;
+  scanner->include_patterns = include_patterns;
+  scanner->include_count = include_count;
+  scanner->max_size = max_size;
+  scanner->min_size = min_size;
+  scanner->max_depth = max_depth;
  scanner->current_depth = 0;
-  scanner->follow_symlinks = options->follow_symlinks;
-  scanner->copy_links = options->copy_links;
-  scanner->safe_links = options->safe_links;
-  scanner->copy_unsafe_links = options->copy_unsafe_links;
-  scanner->checksum = options->checksum;
+  scanner->follow_symlinks = follow_symlinks;
+  scanner->copy_links = copy_links;
+  scanner->safe_links = safe_links;
+  scanner->copy_unsafe_links = copy_unsafe_links;
+  scanner->checksum = checksum;
  scanner->failed = false;
  DirEntry* root = dir_entry_create(root_directory, 0);
  if (!root) {
@@ -171,20 +100,6 @@ DirectoryScanner* directory_scanner_create_with_options(const char* root_directo
  return scanner;
 }

-DirectoryScanner* directory_scanner_create(const char* root_directory, bool use_metadata,
-                                           unsigned long long chunk_size, char** exclude_patterns,
-                                           int exclude_count, char** include_patterns,
-                                           int include_count, unsigned long long max_size,
-                                           unsigned long long min_size, int max_depth,
-                                           bool follow_symlinks, bool copy_links, bool safe_links,
-                                           bool copy_unsafe_links, bool checksum) {
-  ScannerOptions options = {
-      use_metadata,    chunk_size, exclude_patterns, exclude_count,     include_patterns,
-      include_count,   max_size,   min_size,         max_depth,         0,
-      follow_symlinks, copy_links, safe_links,       copy_unsafe_links, checksum};
-  return directory_scanner_create_with_options(root_directory, &options);
-}
-
 void directory_scanner_destroy(DirectoryScanner* scanner) {
  if (scanner == NULL)
    return;
@@ -252,7 +167,7 @@ Chunk* directory_scanner_next(DirectoryScanner* scanner) {
        break;
    }

-    const struct dirent* entry = readdir(scanner->current_dir);
+    struct dirent* entry = readdir(scanner->current_dir);
    if (entry == NULL) {
      closedir(scanner->current_dir);
      scanner->current_dir = NULL;
@@ -264,27 +179,67 @@ 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};
-    ScannerEntry inspected;
-    int inspection = scanner_inspect_entry(&options, scanner->current_path, scanner->current_path,
-                                           entry->d_name, &inspected);
-    if (inspection < 0) {
+    char* cur_path = path_cat(scanner->current_path, entry->d_name);
+    if (!cur_path) {
      scanner->failed = true;
      break;
    }
-    if (inspection == 0)
+    struct stat stats;
+    struct stat lstats;
+    bool is_symlink = false;
+    if (lstat(cur_path, &lstats) != 0) {
+      free(cur_path);
      continue;
-    char* cur_path = inspected.path;
-    struct stat stats = inspected.stats;
+    }
+    is_symlink = S_ISLNK(lstats.st_mode);

-    if (inspected.is_directory) {
+    if (is_symlink && !scanner->follow_symlinks && !scanner->copy_links && !scanner->safe_links &&
+        !scanner->copy_unsafe_links) {
+      free(cur_path);
+      continue;
+    }
+
+    if (is_symlink && scanner->safe_links) {
+      char link_target[4096];
+      ssize_t len = readlink(cur_path, link_target, sizeof(link_target) - 1);
+      if (len < 0) {
+        free(cur_path);
+        continue;
+      }
+      link_target[len] = '\0';
+      if (link_target[0] == '/' ||
+          !safe_relative_link(scanner->current_path, scanner->current_path, link_target)) {
+        free(cur_path);
+        continue;
+      }
+    }
+
+    if (is_symlink && scanner->copy_unsafe_links && !scanner->copy_links) {
+      char link_target[4096];
+      ssize_t len = readlink(cur_path, link_target, sizeof(link_target) - 1);
+      if (len < 0) {
+        free(cur_path);
+        continue;
+      }
+      link_target[len] = '\0';
+      bool unsafe = (link_target[0] == '/');
+      if (!unsafe) {
+        free(cur_path);
+        continue;
+      }
+    }
+
+    bool use_lstat = is_symlink && scanner->follow_symlinks && !scanner->copy_links;
+    if (use_lstat) {
+      stats = lstats;
+    } else {
+      if (stat(cur_path, &stats) != 0) {
+        free(cur_path);
+        continue;
+      }
+    }
+
+    if (S_ISDIR(stats.st_mode)) {
      int next_depth = scanner->current_depth + 1;
      if (scanner->max_depth <= 0 || next_depth < scanner->max_depth) {
        DirEntry* de = dir_entry_create(cur_path, next_depth);
@@ -299,6 +254,38 @@ Chunk* directory_scanner_next(DirectoryScanner* scanner) {
        free(cur_path);
        continue;
      }
+      bool excluded = false;
+      for (int i = 0; i < scanner->exclude_count; i++) {
+        if (glob_match(scanner->exclude_patterns[i], entry->d_name)) {
+          excluded = true;
+          break;
+        }
+      }
+      if (excluded) {
+        free(cur_path);
+        continue;
+      }
+
+      if (scanner->include_count > 0) {
+        bool included = false;
+        for (int i = 0; i < scanner->include_count; i++) {
+          if (glob_match(scanner->include_patterns[i], entry->d_name)) {
+            included = true;
+            break;
+          }
+        }
+        if (!included) {
+          free(cur_path);
+          continue;
+        }
+      }
+
+      if ((scanner->max_size > 0 && (unsigned long long)stats.st_size > scanner->max_size) ||
+          (scanner->min_size > 0 && (unsigned long long)stats.st_size < scanner->min_size)) {
+        free(cur_path);
+        continue;
+      }
+
      File* file = file_create(cur_path);
      if (file == NULL) {
        free(cur_path);
@@ -349,13 +336,29 @@ typedef struct {
  ParallelScanner* ps;
  char** dirs;
  int dir_count;
-  ScannerOptions options;
+  bool use_metadata;
+  unsigned long long chunk_size;
+  char** exclude_patterns;
+  int exclude_count;
+  char** include_patterns;
+  int include_count;
+  unsigned long long max_size;
+  unsigned long long min_size;
+  int max_depth;
+  bool follow_symlinks;
+  bool copy_links;
+  bool safe_links;
+  bool copy_unsafe_links;
+  bool checksum;
 } ParallelWorkerArg;

 static int parallel_worker_thread(void* arg) {
  ParallelWorkerArg* wa = (ParallelWorkerArg*)arg;
  for (int i = 0; i < wa->dir_count; i++) {
-    DirectoryScanner* ds = directory_scanner_create_with_options(wa->dirs[i], &wa->options);
+    DirectoryScanner* ds = directory_scanner_create(
+        wa->dirs[i], wa->use_metadata, wa->chunk_size, wa->exclude_patterns, wa->exclude_count,
+        wa->include_patterns, wa->include_count, wa->max_size, wa->min_size, wa->max_depth,
+        wa->follow_symlinks, wa->copy_links, wa->safe_links, wa->copy_unsafe_links, wa->checksum);
    if (!ds) {
      mtx_lock(&wa->ps->result_mutex);
      wa->ps->failed = true;
@@ -398,10 +401,13 @@ static int parallel_worker_thread(void* arg) {
  return thrd_success;
 }

-ParallelScanner* parallel_scanner_create_with_options(const char* root_directory,
-                                                      const ScannerOptions* options) {
-  if (!root_directory || !options)
-    return NULL;
+ParallelScanner* parallel_scanner_create(char* root_directory, bool use_metadata,
+                                         unsigned long long chunk_size, char** exclude_patterns,
+                                         int exclude_count, char** include_patterns,
+                                         int include_count, unsigned long long max_size,
+                                         unsigned long long min_size, int max_depth,
+                                         int num_threads, bool follow_symlinks, bool copy_links,
+                                         bool safe_links, bool copy_unsafe_links, bool checksum) {
  ParallelScanner* ps = calloc(1, sizeof(ParallelScanner));
  if (!ps)
    return NULL;
@@ -454,27 +460,105 @@ ParallelScanner* parallel_scanner_create_with_options(const char* root_directory
    parallel_scanner_destroy(ps);
    return NULL;
  }
-  const struct dirent* entry;
+  struct dirent* entry;
  while ((entry = readdir(dir)) != NULL) {
    if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
      continue;
-    ScannerEntry inspected;
-    int inspection =
-        scanner_inspect_entry(options, root_directory, root_directory, entry->d_name, &inspected);
-    if (inspection < 0) {
-      ps->failed = true;
+    char* cur_path = path_cat(root_directory, entry->d_name);
+    if (!cur_path)
+      continue;
+    struct stat lstats;
+    if (lstat(cur_path, &lstats) != 0) {
+      free(cur_path);
      continue;
    }
-    if (inspection == 0)
+    bool is_symlink = S_ISLNK(lstats.st_mode);
+
+    // Skip symlinks unless the user explicitly enabled following/copying them.
+    if (is_symlink && !follow_symlinks && !copy_links && !safe_links && !copy_unsafe_links) {
+      free(cur_path);
      continue;
-    char* cur_path = inspected.path;
-    struct stat st = inspected.stats;
-    if (inspected.is_directory) {
+    }
+
+    // --safe-links: reject symlinks pointing outside the source tree.
+    if (is_symlink && safe_links) {
+      char link_target[4096];
+      ssize_t len = readlink(cur_path, link_target, sizeof(link_target) - 1);
+      if (len < 0) {
+        free(cur_path);
+        continue;
+      }
+      link_target[len] = 0;
+      if (link_target[0] == '/' ||
+          !safe_relative_link(root_directory, root_directory, link_target)) {
+        free(cur_path);
+        continue;
+      }
+    }
+
+    // --copy-unsafe-links (without --copy-links): only copy absolute symlinks.
+    if (is_symlink && copy_unsafe_links && !copy_links) {
+      char link_target[4096];
+      ssize_t len = readlink(cur_path, link_target, sizeof(link_target) - 1);
+      if (len < 0) {
+        free(cur_path);
+        continue;
+      }
+      link_target[len] = 0;
+      bool unsafe = (link_target[0] == '/');
+      if (!unsafe) {
+        free(cur_path);
+        continue;
+      }
+    }
+
+    // Determine whether to use lstat or stat results for the entry.
+    struct stat st;
+    bool use_lstat_res = is_symlink && follow_symlinks && !copy_links;
+    if (use_lstat_res) {
+      st = lstats;
+    } else {
+      if (stat(cur_path, &st) != 0) {
+        free(cur_path);
+        continue;
+      }
+    }
+
+    if (S_ISDIR(st.st_mode)) {
      if (!array_list_add(subdirs, cur_path)) {
        free(cur_path);
        ps->failed = true;
      }
    } else {
+      bool excluded = false;
+      for (int i = 0; i < exclude_count; i++) {
+        if (glob_match(exclude_patterns[i], entry->d_name)) {
+          excluded = true;
+          break;
+        }
+      }
+      if (excluded) {
+        free(cur_path);
+        continue;
+      }
+      if (include_count > 0) {
+        bool included = false;
+        for (int i = 0; i < include_count; i++) {
+          if (glob_match(include_patterns[i], entry->d_name)) {
+            included = true;
+            break;
+          }
+        }
+        if (!included) {
+          free(cur_path);
+          continue;
+        }
+      }
+      if ((max_size > 0 && (unsigned long long)st.st_size > max_size) ||
+          (min_size > 0 && (unsigned long long)st.st_size < min_size)) {
+        free(cur_path);
+        continue;
+      }
      File* file = file_create(cur_path);
      free(cur_path);
      if (!file) {
@@ -482,9 +566,9 @@ ParallelScanner* parallel_scanner_create_with_options(const char* root_directory
        continue;
      }
      file->data->size = st.st_size;
-      if (options->use_metadata)
+      if (use_metadata)
        file->metadata = file_metadata_create(&st);
-      if (options->use_metadata && !file->metadata) {
+      if (use_metadata && !file->metadata) {
        file_destroy(file);
        ps->failed = true;
        continue;
@@ -497,7 +581,7 @@ ParallelScanner* parallel_scanner_create_with_options(const char* root_directory
  }
  closedir(dir);

-  unsigned long long cs = options->chunk_size > 0 ? options->chunk_size : DESIRED_CHUNK_SIZE;
+  unsigned long long cs = chunk_size > 0 ? chunk_size : DESIRED_CHUNK_SIZE;
  if (root_files->size > 0) {
    ArrayList* batch = array_list_create(NULL);
    if (!batch) {
@@ -564,7 +648,7 @@ ParallelScanner* parallel_scanner_create_with_options(const char* root_directory
  }
  array_list_delete(root_files);

-  int n = options->num_threads > 0 ? options->num_threads : 4;
+  int n = num_threads > 0 ? num_threads : 4;
  if (n > subdirs->size)
    n = subdirs->size > 0 ? subdirs->size : 1;

@@ -612,8 +696,20 @@ ParallelScanner* parallel_scanner_create_with_options(const char* root_directory
        break;
      }
      wa->dir_count = count;
-      wa->options = *options;
-      wa->options.chunk_size = cs;
+      wa->use_metadata = use_metadata;
+      wa->chunk_size = cs;
+      wa->exclude_patterns = exclude_patterns;
+      wa->exclude_count = exclude_count;
+      wa->include_patterns = include_patterns;
+      wa->include_count = include_count;
+      wa->max_size = max_size;
+      wa->min_size = min_size;
+      wa->max_depth = max_depth;
+      wa->follow_symlinks = follow_symlinks;
+      wa->copy_links = copy_links;
+      wa->safe_links = safe_links;
+      wa->copy_unsafe_links = copy_unsafe_links;
+      wa->checksum = checksum;
      start += count;
      if (thrd_create(&ps->threads[t], parallel_worker_thread, wa) != thrd_success) {
        for (int j = 0; j < count; j++)
@@ -637,20 +733,6 @@ ParallelScanner* parallel_scanner_create_with_options(const char* root_directory
  return ps;
 }

-ParallelScanner* parallel_scanner_create(const char* root_directory, bool use_metadata,
-                                         unsigned long long chunk_size, char** exclude_patterns,
-                                         int exclude_count, char** include_patterns,
-                                         int include_count, unsigned long long max_size,
-                                         unsigned long long min_size, int max_depth,
-                                         int num_threads, bool follow_symlinks, bool copy_links,
-                                         bool safe_links, bool copy_unsafe_links, bool checksum) {
-  ScannerOptions options = {use_metadata,     chunk_size,        exclude_patterns, exclude_count,
-                            include_patterns, include_count,     max_size,         min_size,
-                            max_depth,        num_threads,       follow_symlinks,  copy_links,
-                            safe_links,       copy_unsafe_links, checksum};
-  return parallel_scanner_create_with_options(root_directory, &options);
-}
-
 Chunk* parallel_scanner_next(ParallelScanner* ps) {
  if (ps->initial_chunk) {
    Chunk* c = ps->initial_chunk;
@@ -8,24 +8,6 @@
 #include <threads.h>
 #include <stdatomic.h>

-typedef struct {
-  bool use_metadata;
-  unsigned long long chunk_size;
-  char** exclude_patterns;
-  int exclude_count;
-  char** include_patterns;
-  int include_count;
-  unsigned long long max_size;
-  unsigned long long min_size;
-  int max_depth;
-  int num_threads;
-  bool follow_symlinks;
-  bool copy_links;
-  bool safe_links;
-  bool copy_unsafe_links;
-  bool checksum;
-} ScannerOptions;
-
 typedef struct {
  Queue* directories;
  DIR* current_dir;
@@ -71,21 +53,17 @@ DirectoryScanner* directory_scanner_create(const char* root_directory, bool use_
                                           unsigned long long min_size, int max_depth,
                                           bool follow_symlinks, bool copy_links, bool safe_links,
                                           bool copy_unsafe_links, bool checksum);
-DirectoryScanner* directory_scanner_create_with_options(const char* root_directory,
-                                                        const ScannerOptions* options);
 Chunk* directory_scanner_next(DirectoryScanner* scanner);
 bool directory_scanner_failed(const DirectoryScanner* scanner);
 void directory_scanner_destroy(DirectoryScanner* scanner);

-ParallelScanner* parallel_scanner_create(const char* root_directory, bool use_metadata,
+ParallelScanner* parallel_scanner_create(char* root_directory, bool use_metadata,
                                         unsigned long long chunk_size, char** exclude_patterns,
                                         int exclude_count, char** include_patterns,
                                         int include_count, unsigned long long max_size,
                                         unsigned long long min_size, int max_depth,
                                         int num_threads, bool follow_symlinks, bool copy_links,
                                         bool safe_links, bool copy_unsafe_links, bool checksum);
-ParallelScanner* parallel_scanner_create_with_options(const char* root_directory,
-                                                      const ScannerOptions* options);
 Chunk* parallel_scanner_next(ParallelScanner* scanner);
 bool parallel_scanner_failed(const ParallelScanner* scanner);
 void parallel_scanner_destroy(ParallelScanner* scanner);
@@ -1,9 +1,8 @@
-#include "usage.h"
-#include <stdio.h>
+#include "stdio.h"
 #include <delta.h>
 #include <chunk.h>

-void print_usage(void) {
+static __attribute__((unused)) void print_usage() {
  printf("Usage:\n");
  printf("  fastsync [options] <source> <destination>\n");
  printf("  fastsync [options] --source-dir <src> --dest-dir <dst>\n");
@@ -1,6 +0,0 @@
-#ifndef USAGE_H
-#define USAGE_H
-
-void print_usage(void);
-
-#endif
@@ -1,126 +0,0 @@
-#include "receiver.h"
-
-#include "chunk.h"
-#include "log.h"
-#include "protocol.h"
-#include "utils.h"
-#include <stdlib.h>
-#include <sys/stat.h>
-
-static bool receiver_process_chunk(Chunk* chunk, const ReceiverSink* sink) {
-  for (int i = 0; i < chunk->element_count; i++) {
-    File* file = chunk->items[i];
-    chunk->items[i] = NULL;
-    if (!sink->store_file(file, sink->context)) {
-      chunk_destroy(chunk);
-      return false;
-    }
-  }
-  chunk_destroy(chunk);
-  return true;
-}
-
-static bool receiver_process_batch(Config* config, int file_descriptor) {
-  int count;
-  if (config->checksum || !receive_int(file_descriptor, &count) || count < 0 ||
-      count > MAX_MANIFEST_ENTRIES)
-    return false;
-  for (int i = 0; i < count; i++) {
-    char* check_path = receive_str(file_descriptor);
-    if (!check_path)
-      return false;
-    unsigned long long check_size;
-    long long check_mtime;
-    if (!receive_n_data(file_descriptor, &check_size, sizeof(check_size)) ||
-        !receive_n_data(file_descriptor, &check_mtime, sizeof(check_mtime))) {
-      free(check_path);
-      return false;
-    }
-    if (!utils_valid_batch_path(check_path)) {
-      free(check_path);
-      send_status(file_descriptor, STATUS_ERROR);
-      return false;
-    }
-    char* full_path = path_cat(config->receive_root_directory, check_path);
-    struct stat st;
-    bool has_old = full_path && lstat(full_path, &st) == 0;
-    bool match = has_old && (unsigned long long)st.st_size == check_size &&
-                 (long long)st.st_mtime == check_mtime;
-    bool sent = send_status(file_descriptor, match ? STATUS_OK : STATUS_NEXT);
-    free(full_path);
-    free(check_path);
-    if (!sent)
-      return false;
-  }
-  return true;
-}
-
-int receiver_process(Config* config, int file_descriptor, const ReceiverSink* sink) {
-  Status status;
-  if (!receive_status(file_descriptor, &status))
-    return -1;
-  while (status == STATUS_NEXT || status == STATUS_CHUNK || status == STATUS_CHECK ||
-         status == STATUS_KEEPALIVE || status == STATUS_ABORT || status == STATUS_CHECK_BATCH) {
-    if (status == STATUS_KEEPALIVE) {
-      if (!send_status(file_descriptor, STATUS_KEEPALIVE))
-        return -1;
-      goto next;
-    }
-    if (status == STATUS_ABORT) {
-      log_message(LOG_LEVEL_INFO, "Received abort from client, cleaning up");
-      return -1;
-    }
-    if (status == STATUS_CHECK) {
-      bool skipped;
-      File* file = receive_incremental_check(file_descriptor, config, &skipped);
-      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))
-        return -1;
-      goto next;
-    } 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:
-    if (!receive_status(file_descriptor, &status))
-      goto receive_error;
-  }
-  if (status == STATUS_MANIFEST && receive_manifest(file_descriptor, config, &status) != 0)
-    return -1;
-  if (status != STATUS_FINISHED) {
-    log_message(LOG_LEVEL_ERROR, "Did not receive FINISHED Status");
-    goto receive_error;
-  }
-  if (sink->send_success && !send_status(file_descriptor, STATUS_OK))
-    return -1;
-  return 0;
-
-receive_error:
-  if (sink->send_error)
-    send_status(file_descriptor, STATUS_ERROR);
-  return -1;
-}
-
-static bool receiver_save_file(File* file, void* context) {
-  Config* config = context;
-  bool success =
-      !config->save_to_disk || file_save_to_disk(config->receive_root_directory, file, config);
-  file_destroy(file);
-  return success;
-}
-
-int receiver_receive_files(Config* config, int file_descriptor) {
-  ReceiverSink sink = {receiver_save_file, config, true, true};
-  return receiver_process(config, file_descriptor, &sink);
-}
@@ -1,19 +0,0 @@
-#ifndef RECEIVER_H
-#define RECEIVER_H
-
-#include "config.h"
-#include "file.h"
-
-typedef bool (*ReceiverFileSink)(File* file, void* context);
-
-typedef struct {
-  ReceiverFileSink store_file;
-  void* context;
-  bool send_error;
-  bool send_success;
-} ReceiverSink;
-
-int receiver_process(Config* config, int file_descriptor, const ReceiverSink* sink);
-int receiver_receive_files(Config* config, int file_descriptor);
-
-#endif
@@ -1,20 +1,24 @@
+#include "array_list.h"
+#include "chunk.h"
 #include "config.h"
+#include "data.h"
 #include "file.h"
 #include "log.h"
 #include "multiprocessing.h"
+#include "protocol.h"
 #include "queue.h"
-#include "receiver.h"
 #include "transport_tcp.h"
 #include "transport_tls.h"
 #include "unistd.h"
 #include "utils.h"
-#include <fcntl.h>
-#include <limits.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <limits.h>
+#include <fcntl.h>
 #include <sys/stat.h>
+#include <unistd.h>

 static char* authorized_root;
 static int authorized_root_fd = -1;
@@ -25,6 +29,11 @@ static bool path_is_within(const char* root, const char* path) {
  return strncmp(root, path, n) == 0 && (path[n] == '\0' || path[n] == '/');
 }

+static bool valid_batch_path(const char* path) {
+  return path && path[0] != '\0' && path[0] != '/' && !has_path_traversal(path) &&
+         strchr(path, '\0') == path + strlen(path);
+}
+
 static bool __attribute__((unused)) configure_authorization(const char* root) {
  char resolved[PATH_MAX];
  if (!root || !realpath(root, resolved))
@@ -43,24 +52,131 @@ static bool __attribute__((unused)) configure_authorization(const char* root) {
  return true;
 }

+int receive_files(Config* config, int fd) {
+  Status status;
+  if (!receive_status(fd, &status))
+    return -1;
+
+  while (status == STATUS_NEXT || status == STATUS_CHUNK || status == STATUS_CHECK ||
+         status == STATUS_KEEPALIVE || status == STATUS_ABORT || status == STATUS_CHECK_BATCH) {
+    if (status == STATUS_KEEPALIVE) {
+      send_status(fd, STATUS_KEEPALIVE);
+      goto next;
+    }
+    if (status == STATUS_ABORT) {
+      log_message(LOG_LEVEL_INFO, "Received abort from client, cleaning up");
+      return -1;
+    }
+    if (status == STATUS_CHECK) {
+      bool skipped;
+      File* file = receive_incremental_check(fd, config, &skipped);
+      if (skipped)
+        goto next;
+      if (file == NULL && !skipped)
+        return -1;
+      if (config->save_to_disk &&
+          !file_save_to_disk(config->receive_root_directory, file, config)) {
+        file_destroy(file);
+        send_status(fd, STATUS_ERROR);
+        return -1;
+      }
+      file_destroy(file);
+    } else if (status == STATUS_CHUNK) {
+      Chunk* chunk = receive_chunk_data(fd, config);
+      if (chunk == NULL) {
+        send_status(fd, STATUS_ERROR);
+        return -1;
+      }
+      for (int i = 0; i < chunk->element_count; i++) {
+        if (config->save_to_disk &&
+            !file_save_to_disk(config->receive_root_directory, chunk->items[i], config)) {
+          chunk_destroy(chunk);
+          send_status(fd, STATUS_ERROR);
+          return -1;
+        }
+      }
+      chunk_destroy(chunk);
+    } else if (status == STATUS_CHECK_BATCH) {
+      int count;
+      /* Batch framing has no checksum field yet; never silently downgrade a
+         checksum-enabled transfer into mtime-only matching. */
+      if (config->checksum || !receive_int(fd, &count) || count < 0 || count > MAX_MANIFEST_ENTRIES)
+        return -1;
+      for (int i = 0; i < count; i++) {
+        char* check_path = receive_str(fd);
+        if (!check_path)
+          return -1;
+        unsigned long long check_size;
+        long long check_mtime;
+        if (!receive_n_data(fd, &check_size, sizeof(check_size)) ||
+            !receive_n_data(fd, &check_mtime, sizeof(check_mtime))) {
+          free(check_path);
+          return -1;
+        }
+        if (!valid_batch_path(check_path)) {
+          free(check_path);
+          send_status(fd, STATUS_ERROR);
+          return -1;
+        }
+        char* full_path = path_cat(config->receive_root_directory, check_path);
+        struct stat st;
+        bool has_old = full_path && lstat(full_path, &st) == 0;
+        bool match = has_old && (unsigned long long)st.st_size == check_size &&
+                     (long long)st.st_mtime == check_mtime;
+        bool sent = send_status(fd, match ? STATUS_OK : STATUS_NEXT);
+        free(full_path);
+        free(check_path);
+        if (!sent)
+          return -1;
+      }
+      goto next;
+    } else {
+      File* file = file_receive(config, fd);
+      if (file == NULL) {
+        log_message(LOG_LEVEL_ERROR, "Failed to receive file");
+        send_status(fd, STATUS_ERROR);
+        return -1;
+      }
+      if (config->save_to_disk &&
+          !file_save_to_disk(config->receive_root_directory, file, config)) {
+        file_destroy(file);
+        send_status(fd, STATUS_ERROR);
+        return -1;
+      }
+      file_destroy(file);
+    }
+  next:
+    if (!receive_status(fd, &status)) {
+      send_status(fd, STATUS_ERROR);
+      return -1;
+    }
+  }
+
+  if (status == STATUS_MANIFEST) {
+    if (receive_manifest(fd, config, &status) != 0)
+      return -1;
+  }
+  if (status != STATUS_FINISHED) {
+    log_message(LOG_LEVEL_ERROR, "Did not receive FINISHED Status");
+    send_status(fd, STATUS_ERROR);
+    return -1;
+  }
+  send_status(fd, STATUS_OK);
+  return 0;
+}
+
 void handler(int file_descriptor) {
  SSL* ssl = io_get_ssl();
-  ProtocolSession session;
-  protocol_session_init(&session, file_descriptor, file_descriptor);
-  protocol_session_set_ssl(&session, ssl);
-  protocol_session_bind(&session);
  Config* config = config_receive(file_descriptor);
  if (config == NULL) {
    log_message(LOG_LEVEL_ERROR, "Failed to receive config");
    close(file_descriptor);
-    protocol_session_unbind();
    return;
  }
  if (!authorized_root) {
    log_message(LOG_LEVEL_ERROR, "No server-side destination root configured");
    config_delete(config);
    close(file_descriptor);
-    protocol_session_unbind();
    return;
  }
  char resolved_destination[PATH_MAX];
@@ -72,7 +188,6 @@ void handler(int file_descriptor) {
    free(canonical_destination);
    config_delete(config);
    close(file_descriptor);
-    protocol_session_unbind();
    return;
  }
  if (canonical_destination)
@@ -85,7 +200,6 @@ void handler(int file_descriptor) {
  if (!config->receive_root_directory) {
    config_delete(config);
    close(file_descriptor);
-    protocol_session_unbind();
    return;
  }
  config->use_delete = config->use_delete && allow_delete;
@@ -94,7 +208,6 @@ void handler(int file_descriptor) {
    if (q == NULL) {
      config_delete(config);
      close(file_descriptor);
-      protocol_session_unbind();
      return;
    }
    PipelineContextReceiver* context =
@@ -103,14 +216,14 @@ void handler(int file_descriptor) {
      queue_destroy(q);
      config_delete(config);
      close(file_descriptor);
-      protocol_session_unbind();
      return;
    }
    thrd_t receiver, writer;
-    bool receiver_created = thrd_create(&receiver, receive_thread, context) == thrd_success;
+    bool receiver_created = false;
    bool writer_created = false;
+    receiver_created = (thrd_create(&receiver, receive_thread, context) == thrd_success);
    if (receiver_created)
-      writer_created = thrd_create(&writer, write_thread, context) == thrd_success;
+      writer_created = (thrd_create(&writer, write_thread, context) == thrd_success);
    if (!receiver_created || !writer_created) {
      perror("Error creating Threads");
      if (receiver_created) {
@@ -127,23 +240,22 @@ void handler(int file_descriptor) {
      if (writer_created)
        thrd_join(writer, NULL);
      pipeline_context_receiver_destroy(context);
-      protocol_session_unbind();
      return;
    }
    int receiver_result;
    int writer_result;
    thrd_join(receiver, &receiver_result);
    thrd_join(writer, &writer_result);
-    send_status(file_descriptor, receiver_result == thrd_success && writer_result == thrd_success
-                                     ? STATUS_OK
-                                     : STATUS_ERROR);
+    if (receiver_result == thrd_success && writer_result == thrd_success)
+      send_status(file_descriptor, STATUS_OK);
+    else
+      send_status(file_descriptor, STATUS_ERROR);
    pipeline_context_receiver_destroy(context);
  } else {
-    if (receiver_receive_files(config, file_descriptor) != 0)
+    if (receive_files(config, file_descriptor) != 0)
      log_message(LOG_LEVEL_ERROR, "Transfer failed");
    config_delete(config);
  }
-  protocol_session_unbind();
  close(file_descriptor);
 }

@@ -152,14 +264,16 @@ static Server* g_server = NULL;

 static void cleanup(int sig) {
  (void)sig;
-  if (g_server)
+  if (g_server) {
    server_delete(&g_server);
+  }
  _exit(0);
 }

 static void print_server_usage(void) {
  printf("FastSync Server\n");
-  printf("Usage: fastsync-server [options]\n\n");
+  printf("Usage: fastsync-server [options]\n");
+  printf("\n");
  printf("Options:\n");
  printf("  --stdio             Run in stdio mode (SSH transport)\n");
  printf("  -p <port>           TCP port (default: 8080, range: 1-65535)\n");
@@ -175,7 +289,9 @@ static void print_server_usage(void) {

 int main(int argc, char* argv[]) {
  bool use_tls = false;
-  char *tls_cert = NULL, *tls_key = NULL, *tls_ca = NULL;
+  char* tls_cert = NULL;
+  char* tls_key = NULL;
+  char* tls_ca = NULL;
  int port = 8080;
  const char* destination_root = ".";
  bool stdio_mode = false;
@@ -215,8 +331,11 @@ int main(int argc, char* argv[]) {
      return 1;
    }
  }
-  if (tls_ca && !use_tls)
+
+  if (tls_ca && !use_tls) {
    log_message(LOG_LEVEL_WARNING, "--ca has no effect without --tls");
+  }
+
  signal(SIGINT, cleanup);
  signal(SIGTERM, cleanup);
  if (!configure_authorization(destination_root)) {
@@ -233,7 +352,7 @@ int main(int argc, char* argv[]) {
    return 0;
  }
  g_server = server_create(port);
-  if (!g_server) {
+  if (g_server == NULL) {
    log_message(LOG_LEVEL_ERROR, "Failed to create server");
    return 1;
  }
@@ -255,4 +374,4 @@ int main(int argc, char* argv[]) {
  }
  return 0;
 }
-#endif
+#endif /* !FASTSYNC_SERVER_AS_LIB */
@@ -173,157 +173,102 @@ void config_delete(Config* config) {
  free(config);
 }

-/* Each helper is deliberately ordered to match the wire format. Keep the
- * helper call order in config_send and config_receive unchanged when adding
- * fields. */
-static bool send_core_fields(int fd, const Config* c) {
-  return send_str(fd, c->version) && send_str(fd, c->send_directory) &&
-         send_str(fd, c->receive_root_directory) && send_int(fd, c->save_to_disk) &&
-         send_int(fd, c->use_multithreading) && send_int(fd, c->use_chunk_serialization) &&
-         send_int(fd, c->use_compression) && send_int(fd, c->use_metadata) &&
-         send_int(fd, c->compression_level) &&
-         send_n_data(fd, &c->chunk_size, sizeof(c->chunk_size)) && send_int(fd, c->use_sendfile);
-}
-
-static bool send_delta_fields(int fd, const Config* c) {
-  return send_int(fd, c->use_delete) && send_int(fd, c->use_incremental) &&
-         send_int(fd, c->use_delta) &&
-         send_n_data(fd, &c->delta_block_size, sizeof(c->delta_block_size)) &&
-         send_n_data(fd, &c->delta_max_file_size, sizeof(unsigned long long));
-}
-
-static bool send_file_options(int fd, const Config* c) {
-  return send_int(fd, c->backup) && send_str(fd, c->backup_dir ? c->backup_dir : "") &&
-         send_int(fd, c->follow_symlinks) && send_int(fd, c->copy_links) &&
-         send_int(fd, c->safe_links) && send_int(fd, c->copy_unsafe_links) &&
-         send_int(fd, c->preserve_hard_links) && send_int(fd, c->preserve_acls) &&
-         send_int(fd, c->preserve_xattrs) && send_int(fd, c->preserve_devices) &&
-         send_int(fd, c->preserve_sparse);
-}
-
-static bool send_selection_options(int fd, const Config* c) {
-  return send_int(fd, c->update) && send_int(fd, c->inplace) && send_int(fd, c->append) &&
-         send_int(fd, c->append_verify) && send_int(fd, c->delete_excluded) &&
-         send_int(fd, c->delete_after) && send_n_data(fd, &c->max_delete, sizeof(c->max_delete)) &&
-         send_int(fd, c->relative) && send_int(fd, c->prune_empty_dirs);
-}
-
-static bool send_resume_options(int fd, const Config* c) {
-  return send_str(fd, c->temp_dir ? c->temp_dir : "") && send_int(fd, c->partial) &&
-         send_str(fd, c->partial_dir ? c->partial_dir : "") &&
-         send_str(fd, c->suffix ? c->suffix : "") && send_int(fd, c->delete_before) &&
-         send_int(fd, c->checksum) && send_str(fd, c->compress_choice ? c->compress_choice : "");
-}
-
-static bool receive_core_fields(int fd, Config* c) {
-  int value;
-  c->send_directory = receive_str(fd);
-  c->receive_root_directory = receive_str(fd);
-  if (!c->send_directory || !c->receive_root_directory)
-    return false;
-  if (!receive_int(fd, &value))
-    return false;
-  c->save_to_disk = value;
-  if (!receive_int(fd, &value))
-    return false;
-  c->use_multithreading = value;
-  if (!receive_int(fd, &value))
-    return false;
-  c->use_chunk_serialization = value;
-  if (!receive_int(fd, &value))
-    return false;
-  c->use_compression = value;
-  if (!receive_int(fd, &value))
-    return false;
-  c->use_metadata = value;
-  if (!receive_int(fd, &value))
-    return false;
-  c->compression_level = value;
-  if (!receive_n_data(fd, &c->chunk_size, sizeof(c->chunk_size)))
-    return false;
-  if (!receive_int(fd, &value))
-    return false;
-  c->use_sendfile = value;
-  return true;
-}
-
-static bool receive_delta_fields(int fd, Config* c) {
-  int value;
-  if (!receive_int(fd, &value))
-    return false;
-  c->use_delete = value;
-  if (!receive_int(fd, &value))
-    return false;
-  c->use_incremental = value;
-  if (!receive_int(fd, &value))
-    return false;
-  c->use_delta = value;
-  return receive_n_data(fd, &c->delta_block_size, sizeof(c->delta_block_size)) &&
-         receive_n_data(fd, &c->delta_max_file_size, sizeof(unsigned long long));
-}
-
-static bool receive_file_options(int fd, Config* c) {
-  int value;
-  if (!receive_int(fd, &value))
-    return false;
-  c->backup = value;
-  c->backup_dir = receive_str(fd);
-  if (!c->backup_dir)
-    return false;
-  bool* flags[] = {&c->follow_symlinks,   &c->copy_links,          &c->safe_links,
-                   &c->copy_unsafe_links, &c->preserve_hard_links, &c->preserve_acls,
-                   &c->preserve_xattrs,   &c->preserve_devices,    &c->preserve_sparse};
-  for (size_t i = 0; i < sizeof(flags) / sizeof(flags[0]); i++) {
-    if (!receive_int(fd, &value))
-      return false;
-    *flags[i] = value;
-  }
-  return true;
-}
-
-static bool receive_selection_options(int fd, Config* c) {
-  int value;
-  bool* flags[] = {&c->update,        &c->inplace,         &c->append,
-                   &c->append_verify, &c->delete_excluded, &c->delete_after};
-  for (size_t i = 0; i < sizeof(flags) / sizeof(flags[0]); i++) {
-    if (!receive_int(fd, &value))
-      return false;
-    *flags[i] = value;
-  }
-  if (!receive_n_data(fd, &c->max_delete, sizeof(c->max_delete)))
-    return false;
-  if (!receive_int(fd, &value))
-    return false;
-  c->relative = value;
-  if (!receive_int(fd, &value))
-    return false;
-  c->prune_empty_dirs = value;
-  return true;
-}
-
-static bool receive_resume_options(int fd, Config* c) {
-  int value;
-  c->temp_dir = receive_str(fd);
-  if (!c->temp_dir || !receive_int(fd, &value))
-    return false;
-  c->partial = value;
-  c->partial_dir = receive_str(fd);
-  c->suffix = c->partial_dir ? receive_str(fd) : NULL;
-  if (!c->partial_dir || !c->suffix || !receive_int(fd, &value))
-    return false;
-  c->delete_before = value;
-  if (!receive_int(fd, &value))
-    return false;
-  c->checksum = value;
-  c->compress_choice = receive_str(fd);
-  return c->compress_choice != NULL;
-}
-
+/* Wire format order (must match config_receive and be updated when PROTOCOL_VERSION bumps):
+ * version, send_directory, receive_root_directory, save_to_disk, use_multithreading,
+ * use_chunk_serialization, use_compression, use_metadata, compression_level, chunk_size,
+ * use_sendfile, use_delete, use_incremental, use_delta, delta_block_size, delta_max_file_size,
+ * backup, backup_dir, follow_symlinks, copy_links, safe_links, copy_unsafe_links,
+ * preserve_hard_links, preserve_acls, preserve_xattrs, preserve_devices, preserve_sparse,
+ * update, inplace, append, append_verify, delete_excluded, delete_after, max_delete, relative,
+ * prune_empty_dirs, temp_dir, partial, partial_dir, suffix, delete_before, checksum,
+ * compress_choice, status
+ */
 bool config_send(int file_descriptor, const Config* config) {
-  if (!send_core_fields(file_descriptor, config) || !send_delta_fields(file_descriptor, config) ||
-      !send_file_options(file_descriptor, config) ||
-      !send_selection_options(file_descriptor, config) ||
-      !send_resume_options(file_descriptor, config))
+  if (!send_str(file_descriptor, config->version))
+    return false;
+  if (!send_str(file_descriptor, config->send_directory))
+    return false;
+  if (!send_str(file_descriptor, config->receive_root_directory))
+    return false;
+  if (!send_int(file_descriptor, config->save_to_disk))
+    return false;
+  if (!send_int(file_descriptor, config->use_multithreading))
+    return false;
+  if (!send_int(file_descriptor, config->use_chunk_serialization))
+    return false;
+  if (!send_int(file_descriptor, config->use_compression))
+    return false;
+  if (!send_int(file_descriptor, config->use_metadata))
+    return false;
+  if (!send_int(file_descriptor, config->compression_level))
+    return false;
+  if (!send_n_data(file_descriptor, &config->chunk_size, sizeof(config->chunk_size)))
+    return false;
+  if (!send_int(file_descriptor, config->use_sendfile))
+    return false;
+  if (!send_int(file_descriptor, config->use_delete))
+    return false;
+  if (!send_int(file_descriptor, config->use_incremental))
+    return false;
+  if (!send_int(file_descriptor, config->use_delta))
+    return false;
+  if (!send_n_data(file_descriptor, &config->delta_block_size, sizeof(config->delta_block_size)))
+    return false;
+  if (!send_n_data(file_descriptor, &config->delta_max_file_size, sizeof(unsigned long long)))
+    return false;
+  if (!send_int(file_descriptor, config->backup))
+    return false;
+  if (!send_str(file_descriptor, config->backup_dir ? config->backup_dir : ""))
+    return false;
+  if (!send_int(file_descriptor, config->follow_symlinks))
+    return false;
+  if (!send_int(file_descriptor, config->copy_links))
+    return false;
+  if (!send_int(file_descriptor, config->safe_links))
+    return false;
+  if (!send_int(file_descriptor, config->copy_unsafe_links))
+    return false;
+  if (!send_int(file_descriptor, config->preserve_hard_links))
+    return false;
+  if (!send_int(file_descriptor, config->preserve_acls))
+    return false;
+  if (!send_int(file_descriptor, config->preserve_xattrs))
+    return false;
+  if (!send_int(file_descriptor, config->preserve_devices))
+    return false;
+  if (!send_int(file_descriptor, config->preserve_sparse))
+    return false;
+  if (!send_int(file_descriptor, config->update))
+    return false;
+  if (!send_int(file_descriptor, config->inplace))
+    return false;
+  if (!send_int(file_descriptor, config->append))
+    return false;
+  if (!send_int(file_descriptor, config->append_verify))
+    return false;
+  if (!send_int(file_descriptor, config->delete_excluded))
+    return false;
+  if (!send_int(file_descriptor, config->delete_after))
+    return false;
+  if (!send_n_data(file_descriptor, &config->max_delete, sizeof(config->max_delete)))
+    return false;
+  if (!send_int(file_descriptor, config->relative))
+    return false;
+  if (!send_int(file_descriptor, config->prune_empty_dirs))
+    return false;
+  if (!send_str(file_descriptor, config->temp_dir ? config->temp_dir : ""))
+    return false;
+  if (!send_int(file_descriptor, config->partial))
+    return false;
+  if (!send_str(file_descriptor, config->partial_dir ? config->partial_dir : ""))
+    return false;
+  if (!send_str(file_descriptor, config->suffix ? config->suffix : ""))
+    return false;
+  if (!send_int(file_descriptor, config->delete_before))
+    return false;
+  if (!send_int(file_descriptor, config->checksum))
+    return false;
+  if (!send_str(file_descriptor, config->compress_choice ? config->compress_choice : ""))
    return false;
  Status status;
  if (!receive_status(file_descriptor, &status))
@@ -335,25 +280,159 @@ bool config_send(int file_descriptor, const Config* config) {
  return true;
 }

+/* Wire format order: see the comment above config_send. */
 Config* config_receive(int file_descriptor) {
-  Config* config = config_create();
-  if (!config)
+  Config* config = (Config*)malloc(sizeof(Config));
+  if (config == NULL)
    return NULL;
+  config_set_defaults(config);
  free(config->version);
  config->version = receive_str(file_descriptor);
-  if (!config->version)
-    goto error;
+  if (!config->version) {
+    free(config->server_host);
+    free(config);
+    return NULL;
+  }
  if (strcmp(config->version, PROTOCOL_VERSION) != 0) {
    fprintf(stderr, "Protocol version mismatch: client=%s, server=%s\n", config->version,
            PROTOCOL_VERSION);
+    free(config->version);
+    free(config->server_host);
+    free(config);
    send_status(file_descriptor, STATUS_ERROR);
-    goto error;
+    return NULL;
  }
-  if (!receive_core_fields(file_descriptor, config) ||
-      !receive_delta_fields(file_descriptor, config) ||
-      !receive_file_options(file_descriptor, config) ||
-      !receive_selection_options(file_descriptor, config) ||
-      !receive_resume_options(file_descriptor, config))
+  config->send_directory = receive_str(file_descriptor);
+  if (!config->send_directory) {
+    free(config->version);
+    free(config->server_host);
+    free(config);
+    return NULL;
+  }
+  config->receive_root_directory = receive_str(file_descriptor);
+  if (!config->receive_root_directory) {
+    free(config->version);
+    free(config->send_directory);
+    free(config->server_host);
+    free(config);
+    return NULL;
+  }
+  int tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->save_to_disk = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->use_multithreading = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->use_chunk_serialization = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->use_compression = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->use_metadata = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->compression_level = tmp;
+  if (!receive_n_data(file_descriptor, &config->chunk_size, sizeof(config->chunk_size)))
+    goto error;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->use_sendfile = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->use_delete = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->use_incremental = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->use_delta = tmp;
+  if (!receive_n_data(file_descriptor, &config->delta_block_size, sizeof(config->delta_block_size)))
+    goto error;
+  if (!receive_n_data(file_descriptor, &config->delta_max_file_size, sizeof(unsigned long long)))
+    goto error;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->backup = tmp;
+  config->backup_dir = receive_str(file_descriptor);
+  if (config->backup_dir == NULL)
+    goto error;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->follow_symlinks = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->copy_links = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->safe_links = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->copy_unsafe_links = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->preserve_hard_links = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->preserve_acls = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->preserve_xattrs = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->preserve_devices = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->preserve_sparse = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->update = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->inplace = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->append = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->append_verify = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->delete_excluded = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->delete_after = tmp;
+  if (!receive_n_data(file_descriptor, &config->max_delete, sizeof(config->max_delete)))
+    goto error;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->relative = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->prune_empty_dirs = tmp;
+  config->temp_dir = receive_str(file_descriptor);
+  if (config->temp_dir == NULL)
+    goto error;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->partial = tmp;
+  config->partial_dir = receive_str(file_descriptor);
+  if (config->partial_dir == NULL)
+    goto error;
+  config->suffix = receive_str(file_descriptor);
+  if (config->suffix == NULL)
+    goto error;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->delete_before = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->checksum = tmp;
+  config->compress_choice = receive_str(file_descriptor);
+  if (config->compress_choice == NULL)
    goto error;
  if (config->compress_choice[0] != '\0' && strcmp(config->compress_choice, "zstd") != 0 &&
      strcmp(config->compress_choice, "none") != 0) {
@@ -366,6 +445,15 @@ Config* config_receive(int file_descriptor) {
  return config;

 error:
-  config_delete(config);
+  free(config->version);
+  free(config->send_directory);
+  free(config->receive_root_directory);
+  free(config->server_host);
+  free(config->backup_dir);
+  free(config->temp_dir);
+  free(config->partial_dir);
+  free(config->suffix);
+  free(config->compress_choice);
+  free(config);
  return NULL;
 }
@@ -19,7 +19,6 @@
 #include "config.h"
 #include "data.h"
 #include "file.h"
-#include "file_store.h"
 #include "metadata.h"
 #include "protocol.h"
 #include "utils.h"
@@ -154,8 +153,17 @@ bool file_send_single_calls(File* file, int file_descriptor, bool use_metadata,
  return true;
 }

+static bool to_disk_secure(const char* path, const void* data, unsigned long long data_size,
+                           bool inplace, bool sparse, const FileMetadata* metadata);
+static int open_secure_parent(const char* path, char** leaf_out);
+static bool rename_secure(const char* old_path, const char* new_path);
+static int authorized_root_fd = -1;
+static char* authorized_root_path;
+
 void file_set_authorized_root(int fd, const char* canonical_path) {
-  file_store_set_authorized_root(fd, canonical_path);
+  authorized_root_fd = fd;
+  free(authorized_root_path);
+  authorized_root_path = canonical_path ? str_dup(canonical_path) : NULL;
 }

 static bool path_is_within_root(const char* root, const char* path) {
@@ -272,7 +280,7 @@ bool file_save_to_disk(const char* root_directory, const File* file, const Confi
          mkdir_r(bdir);
          free(backup_dir_path);
        }
-        if (!file_store_rename_secure(disk_path, backup_path)) {
+        if (!rename_secure(disk_path, backup_path)) {
          free(backup_path);
          free(resolved_root);
          free(confined_backup);
@@ -327,8 +335,8 @@ bool file_save_to_disk(const char* root_directory, const File* file, const Confi
  free(resolved_dir);
  free(resolved_root);

-  bool ok = file_store_write_secure(disk_path, file->data->data, file->data->size, inplace, sparse,
-                                    file->metadata);
+  bool ok = to_disk_secure(disk_path, file->data->data, file->data->size, inplace, sparse,
+                           file->metadata);
  free(confined_backup);
  free(confined_partial);
  free(disk_path);
@@ -524,7 +532,7 @@ File* receive_incremental_check(int fd, const Config* config, bool* skipped) {
  int old_fd = -1;
  if (full_path) {
    char* leaf = NULL;
-    int parent_fd = file_store_open_secure_parent(full_path, &leaf);
+    int parent_fd = open_secure_parent(full_path, &leaf);
    if (parent_fd >= 0) {
      old_fd = openat(parent_fd, leaf, O_RDONLY | O_CLOEXEC | O_NOFOLLOW);
      free(leaf);
@@ -643,11 +651,243 @@ File* receive_incremental_check(int fd, const Config* config, bool* skipped) {
  return file;
 }

+static int open_secure_parent(const char* path, char** leaf_out) {
+  char* copy = str_dup(path);
+  if (!copy)
+    return -1;
+  char* parent = dirname(copy);
+  const char* slash = strrchr(path, '/');
+  char* leaf = str_dup(slash ? slash + 1 : path);
+  if (!leaf) {
+    free(copy);
+    return -1;
+  }
+  int fd;
+  if (authorized_root_fd >= 0 && authorized_root_path && path[0] == '/' &&
+      path_is_within_root(authorized_root_path, path)) {
+    fd = dup(authorized_root_fd);
+    size_t root_len = strlen(authorized_root_path);
+    char* relative = str_dup(path + root_len);
+    if (!relative) {
+      free(copy);
+      free(leaf);
+      close(fd);
+      return -1;
+    }
+    free(copy);
+    copy = relative;
+    parent = dirname(copy);
+  } else {
+    fd = (parent[0] == '/') ? open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC)
+                            : open(".", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+  }
+  if (fd < 0) {
+    free(copy);
+    free(leaf);
+    return -1;
+  }
+  char* save = NULL;
+  char* component = strtok_r(parent, "/", &save);
+  while (component) {
+    if (strcmp(component, ".") != 0 && strcmp(component, "..") != 0) {
+      int next = openat(fd, component, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
+      if (next < 0 && errno == ENOENT && mkdirat(fd, component, 0755) == 0)
+        next = openat(fd, component, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
+      if (next < 0) {
+        close(fd);
+        free(copy);
+        free(leaf);
+        return -1;
+      }
+      close(fd);
+      fd = next;
+    }
+    component = strtok_r(NULL, "/", &save);
+  }
+  free(copy);
+  *leaf_out = leaf;
+  return fd;
+}
+
+static bool rename_secure(const char* old_path, const char* new_path) {
+  char *old_leaf = NULL, *new_leaf = NULL;
+  int old_parent = open_secure_parent(old_path, &old_leaf);
+  int new_parent = open_secure_parent(new_path, &new_leaf);
+  bool ok = old_parent >= 0 && new_parent >= 0 &&
+            renameat(old_parent, old_leaf, new_parent, new_leaf) == 0;
+  if (old_parent >= 0)
+    close(old_parent);
+  if (new_parent >= 0)
+    close(new_parent);
+  free(old_leaf);
+  free(new_leaf);
+  return ok;
+}
+
+static bool write_all(int fd, const void* data, unsigned long long size) {
+  const unsigned char* p = data;
+  unsigned long long done = 0;
+  while (done < size) {
+    ssize_t n = write(fd, p + done, (size_t)(size - done));
+    if (n < 0 && errno == EINTR)
+      continue;
+    if (n <= 0)
+      return false;
+    done += (unsigned long long)n;
+  }
+  return true;
+}
+
+static bool to_disk_secure(const char* path, const void* data, unsigned long long data_size,
+                           bool inplace, bool sparse, const FileMetadata* metadata) {
+  char* leaf = NULL;
+  int dirfd = open_secure_parent(path, &leaf);
+  if (dirfd < 0)
+    return false;
+  int fd = -1;
+  bool ok = false;
+  if (inplace) {
+    fd = openat(dirfd, leaf, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW, 0644);
+    if (fd >= 0) {
+      if (!sparse || data_size == 0 || ftruncate(fd, (off_t)data_size) == 0)
+        ok = write_all(fd, data, data_size);
+      if (ok && metadata)
+        ok = file_restore_metadata_fd(fd, metadata);
+    }
+  } else {
+    char tmp[NAME_MAX];
+    for (unsigned int i = 0; i < 100 && !ok; ++i) {
+      snprintf(tmp, sizeof(tmp), ".%s.tmp.%ld.%u", leaf, (long)getpid(), i);
+      fd = openat(dirfd, tmp, O_WRONLY | O_CREAT | O_EXCL | O_CLOEXEC | O_NOFOLLOW, 0600);
+      if (fd < 0)
+        continue;
+      if (sparse && data_size > 0)
+        ok = ftruncate(fd, (off_t)data_size) == 0;
+      if (ok || (!sparse || data_size == 0))
+        ok = write_all(fd, data, data_size);
+      if (ok && metadata)
+        ok = file_restore_metadata_fd(fd, metadata);
+      if (close(fd) != 0)
+        ok = false;
+      fd = -1;
+      if (ok && renameat(dirfd, tmp, dirfd, leaf) != 0)
+        ok = false;
+      if (!ok)
+        unlinkat(dirfd, tmp, 0);
+    }
+  }
+  if (fd >= 0)
+    close(fd);
+  close(dirfd);
+  free(leaf);
+  return ok;
+}
+
 bool to_disk(const char* path, const void* data, unsigned long long data_size, bool inplace,
             bool sparse) {
  if (!path || (!data && data_size != 0) || has_path_traversal(path))
    return false;
-  return file_store_write_secure(path, data, data_size, inplace, sparse, NULL);
+  return to_disk_secure(path, data, data_size, inplace, sparse, NULL);
+  /* Kept below only as historical context; all writes use descriptor-relative operations. */
+  char* tmp_path = NULL;
+  char* directory = NULL;
+
+  char* path_dup = str_dup(path);
+  if (!path_dup)
+    return false;
+  const char* dir_result = dirname(path_dup);
+  directory = str_dup(dir_result);
+  free(path_dup);
+  if (!directory)
+    return false;
+
+  bool ok = true;
+  if (!mkdir_r(directory))
+    goto done;
+
+  if (inplace) {
+    FILE* file_pointer = fopen(path, "wb");
+    if (file_pointer == NULL) {
+      perror("Could not open file for inplace write");
+      ok = false;
+      goto done;
+    }
+    if (sparse && data_size > 0) {
+      if (fseek(file_pointer, data_size - 1, SEEK_SET) != 0) {
+        perror("Failed to seek for sparse file");
+        fclose(file_pointer);
+        ok = false;
+        goto done;
+      }
+      if (fwrite("", 1, 1, file_pointer) != 1) {
+        perror("Failed to write sparse file");
+        fclose(file_pointer);
+        ok = false;
+        goto done;
+      }
+      rewind(file_pointer);
+    }
+    if (data_size > 0 && fwrite(data, 1, data_size, file_pointer) != data_size) {
+      perror("Failed to write all data to file");
+      fclose(file_pointer);
+      ok = false;
+      goto done;
+    }
+    fclose(file_pointer);
+    free(directory);
+    return true;
+  }
+
+  size_t path_len = strlen(path);
+  tmp_path = malloc(path_len + 5);
+  if (!tmp_path) {
+    ok = false;
+    goto done;
+  }
+  memcpy(tmp_path, path, path_len);
+  memcpy(tmp_path + path_len, ".tmp", 5);
+
+  FILE* file_pointer = fopen(tmp_path, "wb");
+  if (file_pointer == NULL) {
+    perror("Could not open temporary file");
+    ok = false;
+    goto done;
+  }
+  if (sparse && data_size > 0) {
+    if (fseek(file_pointer, data_size - 1, SEEK_SET) != 0) {
+      perror("Failed to seek for sparse file");
+      fclose(file_pointer);
+      ok = false;
+      goto done;
+    }
+    if (fwrite("", 1, 1, file_pointer) != 1) {
+      perror("Failed to write sparse file");
+      fclose(file_pointer);
+      ok = false;
+      goto done;
+    }
+    rewind(file_pointer);
+  }
+  if (fwrite(data, 1, data_size, file_pointer) != data_size) {
+    perror("Failed to write all data to temporary file");
+    fclose(file_pointer);
+    unlink(tmp_path);
+    ok = false;
+    goto done;
+  }
+  fclose(file_pointer);
+
+  if (rename(tmp_path, path) != 0) {
+    perror("Failed to atomically rename temporary file");
+    unlink(tmp_path);
+    ok = false;
+    goto done;
+  }
+
+done:
+  free(tmp_path);
+  free(directory);
+  return ok;
 }

 bool file_send_sendfile(File* file, int file_descriptor, bool use_metadata, int compression_level,
@@ -1,159 +0,0 @@
-#include <errno.h>
-#include <fcntl.h>
-#include <libgen.h>
-#include <limits.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-
-#include "file_store.h"
-#include "metadata.h"
-#include "utils.h"
-
-static int authorized_root_fd = -1;
-static char* authorized_root_path;
-
-static bool path_is_within_root(const char* root, const char* path) {
-  size_t root_length = strlen(root);
-  return strncmp(root, path, root_length) == 0 &&
-         (path[root_length] == '\0' || path[root_length] == '/');
-}
-
-void file_store_set_authorized_root(int fd, const char* canonical_path) {
-  authorized_root_fd = fd;
-  free(authorized_root_path);
-  authorized_root_path = canonical_path ? str_dup(canonical_path) : NULL;
-}
-
-int file_store_open_secure_parent(const char* path, char** leaf_out) {
-  char* copy = str_dup(path);
-  if (!copy)
-    return -1;
-  char* parent = dirname(copy);
-  const char* slash = strrchr(path, '/');
-  char* leaf = str_dup(slash ? slash + 1 : path);
-  if (!leaf) {
-    free(copy);
-    return -1;
-  }
-  int fd;
-  if (authorized_root_fd >= 0 && authorized_root_path && path[0] == '/' &&
-      path_is_within_root(authorized_root_path, path)) {
-    fd = dup(authorized_root_fd);
-    size_t root_length = strlen(authorized_root_path);
-    char* relative = str_dup(path + root_length);
-    if (!relative) {
-      free(copy);
-      free(leaf);
-      close(fd);
-      return -1;
-    }
-    free(copy);
-    copy = relative;
-    parent = dirname(copy);
-  } else {
-    fd = (parent[0] == '/') ? open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC)
-                            : open(".", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
-  }
-  if (fd < 0) {
-    free(copy);
-    free(leaf);
-    return -1;
-  }
-  char* save = NULL;
-  char* component = strtok_r(parent, "/", &save);
-  while (component) {
-    if (strcmp(component, ".") != 0 && strcmp(component, "..") != 0) {
-      int next = openat(fd, component, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
-      if (next < 0 && errno == ENOENT && mkdirat(fd, component, 0755) == 0)
-        next = openat(fd, component, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
-      if (next < 0) {
-        close(fd);
-        free(copy);
-        free(leaf);
-        return -1;
-      }
-      close(fd);
-      fd = next;
-    }
-    component = strtok_r(NULL, "/", &save);
-  }
-  free(copy);
-  *leaf_out = leaf;
-  return fd;
-}
-
-bool file_store_rename_secure(const char* old_path, const char* new_path) {
-  char *old_leaf = NULL, *new_leaf = NULL;
-  int old_parent = file_store_open_secure_parent(old_path, &old_leaf);
-  int new_parent = file_store_open_secure_parent(new_path, &new_leaf);
-  bool ok = old_parent >= 0 && new_parent >= 0 &&
-            renameat(old_parent, old_leaf, new_parent, new_leaf) == 0;
-  if (old_parent >= 0)
-    close(old_parent);
-  if (new_parent >= 0)
-    close(new_parent);
-  free(old_leaf);
-  free(new_leaf);
-  return ok;
-}
-
-static bool write_all(int fd, const void* data, unsigned long long size) {
-  const unsigned char* p = data;
-  unsigned long long done = 0;
-  while (done < size) {
-    ssize_t n = write(fd, p + done, (size_t)(size - done));
-    if (n < 0 && errno == EINTR)
-      continue;
-    if (n <= 0)
-      return false;
-    done += (unsigned long long)n;
-  }
-  return true;
-}
-
-bool file_store_write_secure(const char* path, const void* data, unsigned long long data_size,
-                             bool inplace, bool sparse, const FileMetadata* metadata) {
-  char* leaf = NULL;
-  int dirfd = file_store_open_secure_parent(path, &leaf);
-  if (dirfd < 0)
-    return false;
-  int fd = -1;
-  bool ok = false;
-  if (inplace) {
-    fd = openat(dirfd, leaf, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW, 0644);
-    if (fd >= 0) {
-      if (!sparse || data_size == 0 || ftruncate(fd, (off_t)data_size) == 0)
-        ok = write_all(fd, data, data_size);
-      if (ok && metadata)
-        ok = file_restore_metadata_fd(fd, metadata);
-    }
-  } else {
-    char tmp[NAME_MAX];
-    for (unsigned int i = 0; i < 100 && !ok; ++i) {
-      snprintf(tmp, sizeof(tmp), ".%s.tmp.%ld.%u", leaf, (long)getpid(), i);
-      fd = openat(dirfd, tmp, O_WRONLY | O_CREAT | O_EXCL | O_CLOEXEC | O_NOFOLLOW, 0600);
-      if (fd < 0)
-        continue;
-      if (sparse && data_size > 0)
-        ok = ftruncate(fd, (off_t)data_size) == 0;
-      if (ok || (!sparse || data_size == 0))
-        ok = write_all(fd, data, data_size);
-      if (ok && metadata)
-        ok = file_restore_metadata_fd(fd, metadata);
-      if (close(fd) != 0)
-        ok = false;
-      fd = -1;
-      if (ok && renameat(dirfd, tmp, dirfd, leaf) != 0)
-        ok = false;
-      if (!ok)
-        unlinkat(dirfd, tmp, 0);
-    }
-  }
-  if (fd >= 0)
-    close(fd);
-  close(dirfd);
-  free(leaf);
-  return ok;
-}
@@ -1,13 +0,0 @@
-#ifndef FILE_STORE_H
-#define FILE_STORE_H
-
-#include "file.h"
-#include <stdbool.h>
-
-void file_store_set_authorized_root(int fd, const char* canonical_path);
-int file_store_open_secure_parent(const char* path, char** leaf_out);
-bool file_store_rename_secure(const char* old_path, const char* new_path);
-bool file_store_write_secure(const char* path, const void* data, unsigned long long data_size,
-                             bool inplace, bool sparse, const FileMetadata* metadata);
-
-#endif
@@ -1,5 +1,4 @@
 #include "multiprocessing.h"
-#include "receiver.h"

 #include "array_list.h"
 #include "chunk.h"
@@ -15,6 +14,10 @@
 #include <string.h>
 #include <threads.h>

+static bool valid_batch_path(const char* path) {
+  return path && path[0] != '\0' && path[0] != '/' && !has_path_traversal(path);
+}
+
 PipelineContextSender* pipeline_context_sender_create(Config* config, Queue* queue_scanner,
                                                      Queue* queue_loader) {
  PipelineContextSender* context = malloc(sizeof(PipelineContextSender));
@@ -98,8 +101,6 @@ PipelineContextReceiver* pipeline_context_receiver_create(Config* config, Queue*
  context->queue = queue;
  context->file_descriptor = file_descriptor;
  context->ssl = ssl;
-  protocol_session_init(&context->session, file_descriptor, file_descriptor);
-  protocol_session_set_ssl(&context->session, ssl);
  context->receiver_done = false;
  atomic_init(&context->cancelled, false);
  int init = 0;
@@ -136,14 +137,24 @@ void pipeline_context_receiver_destroy(PipelineContextReceiver* context) {
  free(context);
 }

-static bool receiver_enqueue_file(File* file, void* context_pointer) {
-  PipelineContextReceiver* context = context_pointer;
-  if (queue_enqueue_multithreaded_cancel(context->queue, file, &context->mutex,
-                                         &context->condition_not_empty,
-                                         &context->condition_not_full, &context->cancelled))
-    return true;
-  file_destroy(file);
-  return false;
+static bool receive_chunk_enqueue(int file_descriptor, PipelineContextReceiver* context) {
+  Chunk* chunk = receive_chunk_data(file_descriptor, context->config);
+  if (chunk == NULL)
+    return false;
+
+  for (int i = 0; i < chunk->element_count; i++) {
+    File* file = chunk->items[i];
+    chunk->items[i] = NULL;
+    if (!queue_enqueue_multithreaded_cancel(context->queue, file, &context->mutex,
+                                            &context->condition_not_empty,
+                                            &context->condition_not_full, &context->cancelled)) {
+      file_destroy(file);
+      chunk_destroy(chunk);
+      return false;
+    }
+  }
+  chunk_destroy(chunk);
+  return true;
 }

 static void receiver_thread_fail(PipelineContextReceiver* context) {
@@ -156,29 +167,119 @@ static void receiver_thread_fail(PipelineContextReceiver* context) {
 }

 int receive_thread(void* pipeline_context) {
+#define RECEIVE_THREAD_FAIL()                                                                      \
+  do {                                                                                             \
+    receiver_thread_fail(context);                                                                 \
+    return thrd_error;                                                                             \
+  } while (0)
  PipelineContextReceiver* context = (PipelineContextReceiver*)pipeline_context;
-  protocol_session_bind(&context->session);
+  if (context->ssl)
+    io_set_ssl(context->ssl);
  mtx_lock(&context->mutex);
  int file_descriptor = context->file_descriptor;
  const Config* config = context->config;
  mtx_unlock(&context->mutex);

-  ReceiverSink sink = {receiver_enqueue_file, context, false, false};
-  if (receiver_process((Config*)config, file_descriptor, &sink) != 0) {
-    receiver_thread_fail(context);
-    protocol_session_unbind();
-    return thrd_error;
+  Status status;
+  if (!receive_status(file_descriptor, &status))
+    RECEIVE_THREAD_FAIL();
+  while (status == STATUS_NEXT || status == STATUS_CHUNK || status == STATUS_CHECK ||
+         status == STATUS_KEEPALIVE || status == STATUS_ABORT || status == STATUS_CHECK_BATCH) {
+    if (status == STATUS_KEEPALIVE) {
+      if (!send_status(file_descriptor, STATUS_KEEPALIVE))
+        RECEIVE_THREAD_FAIL();
+      goto next;
+    }
+    if (status == STATUS_ABORT) {
+      log_message(LOG_LEVEL_INFO, "Received abort from client, cleaning up");
+      RECEIVE_THREAD_FAIL();
+    }
+    if (status == STATUS_CHECK) {
+      bool skipped;
+      File* file = receive_incremental_check(file_descriptor, config, &skipped);
+      if (!skipped) {
+        if (file == NULL)
+          RECEIVE_THREAD_FAIL();
+        if (!queue_enqueue_multithreaded_cancel(
+                context->queue, file, &context->mutex, &context->condition_not_empty,
+                &context->condition_not_full, &context->cancelled)) {
+          file_destroy(file);
+          RECEIVE_THREAD_FAIL();
+        }
+      }
+    } else if (status == STATUS_CHUNK) {
+      if (!receive_chunk_enqueue(file_descriptor, context))
+        RECEIVE_THREAD_FAIL();
+    } else if (status == STATUS_CHECK_BATCH) {
+      int count;
+      if (config->checksum || !receive_int(file_descriptor, &count) || count < 0 ||
+          count > MAX_MANIFEST_ENTRIES)
+        RECEIVE_THREAD_FAIL();
+      for (int i = 0; i < count; i++) {
+        char* check_path = receive_str(file_descriptor);
+        if (!check_path)
+          RECEIVE_THREAD_FAIL();
+        unsigned long long check_size;
+        long long check_mtime;
+        if (!receive_n_data(file_descriptor, &check_size, sizeof(check_size)) ||
+            !receive_n_data(file_descriptor, &check_mtime, sizeof(check_mtime))) {
+          free(check_path);
+          RECEIVE_THREAD_FAIL();
+        }
+        if (!valid_batch_path(check_path)) {
+          free(check_path);
+          if (!send_status(file_descriptor, STATUS_ERROR))
+            RECEIVE_THREAD_FAIL();
+          RECEIVE_THREAD_FAIL();
+        }
+        char* full_path = path_cat(config->receive_root_directory, check_path);
+        struct stat st;
+        bool has_old = full_path && lstat(full_path, &st) == 0;
+        bool match = has_old && (unsigned long long)st.st_size == check_size &&
+                     (long long)st.st_mtime == check_mtime;
+        if (!send_status(file_descriptor, match ? STATUS_OK : STATUS_NEXT))
+          RECEIVE_THREAD_FAIL();
+        free(full_path);
+        free(check_path);
+      }
+      goto next;
+    } else {
+      File* file = file_receive(config, file_descriptor);
+      if (file) {
+        if (!queue_enqueue_multithreaded_cancel(
+                context->queue, file, &context->mutex, &context->condition_not_empty,
+                &context->condition_not_full, &context->cancelled)) {
+          file_destroy(file);
+          receiver_thread_fail(context);
+          return thrd_error;
+        }
+      } else {
+        log_message(LOG_LEVEL_ERROR, "Failed to receive file");
+        RECEIVE_THREAD_FAIL();
+      }
+    }
+  next:
+    if (!receive_status(file_descriptor, &status))
+      RECEIVE_THREAD_FAIL();
  }
+  if (status == STATUS_MANIFEST) {
+    if (receive_manifest(file_descriptor, config, &status) != 0)
+      RECEIVE_THREAD_FAIL();
+  }
+  if (status != STATUS_FINISHED)
+    RECEIVE_THREAD_FAIL();
  mtx_lock(&context->mutex);
  context->receiver_done = true;
  cnd_signal(&context->condition_not_empty);
  mtx_unlock(&context->mutex);
-  protocol_session_unbind();
+#undef RECEIVE_THREAD_FAIL
  return thrd_success;
 }

 int write_thread(void* pipeline_context) {
  PipelineContextReceiver* context = (PipelineContextReceiver*)pipeline_context;
+  if (context->ssl)
+    io_set_ssl(context->ssl);
  mtx_lock(&context->mutex);
  bool save_to_disk = context->config->save_to_disk;
  char* root_directory = str_dup(context->config->receive_root_directory);
@@ -35,7 +35,6 @@ typedef struct PipelineContextReceiver {
  Config* config;
  int file_descriptor;
  SSL* ssl;
-  ProtocolSession session;
  mtx_t mutex;
  cnd_t condition_not_full;
  cnd_t condition_not_empty;
@@ -18,7 +18,6 @@
 static __thread int io_read_fd = -1;
 static __thread int io_write_fd = -1;
 static __thread SSL* io_ssl;
-static __thread ProtocolSession* bound_session;

 static unsigned long long io_bwlimit = 0;
 static long long bw_tokens = 0;
@@ -29,7 +28,6 @@ static once_flag bw_mutex_once = ONCE_FLAG_INIT;
 static __thread unsigned long long total_allocated_bytes = 0;

 void io_set_fds(int read_fd, int write_fd) {
-  bound_session = NULL;
  io_read_fd = read_fd;
  io_write_fd = write_fd;
  /* A descriptor switch starts a new transport; never reuse a TLS object
@@ -38,29 +36,6 @@ void io_set_fds(int read_fd, int write_fd) {
  total_allocated_bytes = 0;
 }

-void protocol_session_init(ProtocolSession* session, int read_fd, int write_fd) {
-  if (!session)
-    return;
-  memset(session, 0, sizeof(*session));
-  session->read_fd = read_fd;
-  session->write_fd = write_fd;
-  if (io_bwlimit)
-    protocol_session_set_bwlimit(session, io_bwlimit);
-}
-
-void protocol_session_bind(ProtocolSession* session) {
-  bound_session = session;
-}
-
-void protocol_session_unbind(void) {
-  bound_session = NULL;
-}
-
-void protocol_session_set_ssl(ProtocolSession* session, SSL* ssl) {
-  if (session)
-    session->ssl = ssl;
-}
-
 static void bw_mutex_init(void) {
  mtx_init(&bw_mutex, mtx_plain);
 }
@@ -74,51 +49,39 @@ void io_set_bwlimit(unsigned long long bytes_per_sec) {
  mtx_unlock(&bw_mutex);
 }

-void protocol_session_set_bwlimit(ProtocolSession* session, unsigned long long bytes_per_sec) {
-  if (!session)
-    return;
-  session->bwlimit = bytes_per_sec;
-  session->bw_tokens = (long long)bytes_per_sec;
-  struct timespec now;
-  clock_gettime(CLOCK_MONOTONIC, &now);
-  session->bw_last_refill_sec = now.tv_sec;
-  session->bw_last_refill_nsec = now.tv_nsec;
-}
-
-static void bw_throttle_session(ProtocolSession* session, size_t bytes_written) {
-  if (session->bwlimit == 0)
+static void bw_throttle(size_t bytes_written) {
+  if (io_bwlimit == 0)
    return;
+  call_once(&bw_mutex_once, bw_mutex_init);
+  mtx_lock(&bw_mutex);

  struct timespec now;
  clock_gettime(CLOCK_MONOTONIC, &now);

-  long long elapsed_ns = (now.tv_sec - session->bw_last_refill_sec) * 1000000000LL +
-                         (now.tv_nsec - session->bw_last_refill_nsec);
-  session->bw_last_refill_sec = now.tv_sec;
-  session->bw_last_refill_nsec = now.tv_nsec;
+  long long elapsed_ns =
+      (now.tv_sec - bw_last_refill.tv_sec) * 1000000000LL + (now.tv_nsec - bw_last_refill.tv_nsec);
+  bw_last_refill = now;

-  long long tokens_to_add = (long long)((double)session->bwlimit * elapsed_ns / 1000000000.0);
-  session->bw_tokens += tokens_to_add;
-  if (session->bw_tokens > (long long)session->bwlimit)
-    session->bw_tokens = (long long)session->bwlimit;
+  long long tokens_to_add = (long long)((double)io_bwlimit * elapsed_ns / 1000000000.0);
+  bw_tokens += tokens_to_add;
+  if (bw_tokens > (long long)io_bwlimit)
+    bw_tokens = (long long)io_bwlimit;

-  session->bw_tokens -= bytes_written;
+  bw_tokens -= (long long)bytes_written;

-  if (session->bw_tokens < 0) {
-    long long deficit_us =
-        (long long)((double)(-session->bw_tokens) / session->bwlimit * 1000000.0);
+  if (bw_tokens < 0) {
+    long long deficit_us = (long long)((double)(-bw_tokens) / io_bwlimit * 1000000.0);
    if (deficit_us >= 1000)
      poll(NULL, 0, (int)(deficit_us / 1000));
    else
      usleep((useconds_t)deficit_us);
-    session->bw_tokens = 0;
-    session->bw_last_refill_sec = now.tv_sec;
-    session->bw_last_refill_nsec = now.tv_nsec;
+    bw_tokens = 0;
+    clock_gettime(CLOCK_MONOTONIC, &bw_last_refill);
  }
+  mtx_unlock(&bw_mutex);
 }

 void io_set_ssl(SSL* ssl) {
-  bound_session = NULL;
  io_ssl = ssl;
 }

@@ -126,32 +89,8 @@ SSL* io_get_ssl(void) {
  return io_ssl;
 }

-static ProtocolSession* legacy_session(void) {
-  static __thread ProtocolSession session;
-  if (bound_session)
-    return bound_session;
-  session.read_fd = io_read_fd;
-  session.write_fd = io_write_fd;
-  session.ssl = io_ssl;
-  session.bwlimit = io_bwlimit;
-  session.bw_tokens = (unsigned long long)(bw_tokens < 0 ? 0 : bw_tokens);
-  session.bw_last_refill_sec = bw_last_refill.tv_sec;
-  session.bw_last_refill_nsec = bw_last_refill.tv_nsec;
-  return &session;
-}
-
-bool send_n_data(int file_descriptor, const void* data, size_t data_size) {
-  ProtocolSession* session = legacy_session();
-  if (session->write_fd == -1)
-    session->write_fd = file_descriptor;
-  return protocol_send_n_data(session, data, data_size);
-}
-
-bool receive_n_data(int file_descriptor, void* data, size_t data_size) {
-  ProtocolSession* session = legacy_session();
-  if (session->read_fd == -1)
-    session->read_fd = file_descriptor;
-  return protocol_receive_n_data(session, data, data_size);
+static int io_fd(int dir_fd, int file_descriptor) {
+  return (dir_fd != -1) ? dir_fd : file_descriptor;
 }

 static int deadline_remaining_ms(const struct timespec* deadline) {
@@ -165,11 +104,9 @@ static int deadline_remaining_ms(const struct timespec* deadline) {
  return ms > INT_MAX ? INT_MAX : (int)ms;
 }

-bool protocol_send_n_data(ProtocolSession* session, const void* data, size_t data_size) {
+bool send_n_data(int file_descriptor, const void* data, size_t data_size) {
  log_message(LOG_LEVEL_DEBUG, "    Sending n Data: %zu", data_size);
-  if (!session)
-    return false;
-  int fd = session->write_fd;
+  int fd = io_fd(io_write_fd, file_descriptor);
  struct timespec deadline;
  clock_gettime(CLOCK_MONOTONIC, &deadline);
  deadline.tv_sec += SEND_TIMEOUT_SEC;
@@ -177,7 +114,7 @@ bool protocol_send_n_data(ProtocolSession* session, const void* data, size_t dat
  ssize_t total_bytes_send = 0;
  while ((size_t)total_bytes_send < data_size) {
    size_t chunk = data_size - total_bytes_send;
-    if (session->bwlimit > 0 && chunk > 65536)
+    if (io_bwlimit > 0 && chunk > 65536)
      chunk = 65536;
    struct pollfd pfd = {.fd = fd, .events = wait_events};
    int poll_result = poll(&pfd, 1, deadline_remaining_ms(&deadline));
@@ -190,13 +127,13 @@ bool protocol_send_n_data(ProtocolSession* session, const void* data, size_t dat
    if (pfd.revents & (POLLERR | POLLNVAL))
      return false;
    ssize_t bytes_send;
-    if (session->ssl)
-      bytes_send = SSL_write(session->ssl, (const char*)data + total_bytes_send, chunk);
+    if (io_ssl)
+      bytes_send = SSL_write(io_ssl, (const char*)data + total_bytes_send, chunk);
    else
      bytes_send = write(fd, (const char*)data + total_bytes_send, chunk);
    if (bytes_send <= 0) {
-      if (session->ssl) {
-        int ssl_err = SSL_get_error(session->ssl, (int)bytes_send);
+      if (io_ssl) {
+        int ssl_err = SSL_get_error(io_ssl, (int)bytes_send);
        if (ssl_err == SSL_ERROR_WANT_WRITE || ssl_err == SSL_ERROR_WANT_READ) {
          wait_events = ssl_err == SSL_ERROR_WANT_WRITE ? POLLOUT : POLLIN;
          continue;
@@ -205,18 +142,16 @@ bool protocol_send_n_data(ProtocolSession* session, const void* data, size_t dat
      log_message(LOG_LEVEL_ERROR, "Could not send data");
      return false;
    }
-    bw_throttle_session(session, (size_t)bytes_send);
+    bw_throttle((size_t)bytes_send);
    total_bytes_send += bytes_send;
  }
  log_message(LOG_LEVEL_DEBUG, "    Send n Data: %zu", total_bytes_send);
  return true;
 }

-bool protocol_receive_n_data(ProtocolSession* session, void* data, size_t data_size) {
+bool receive_n_data(int file_descriptor, void* data, size_t data_size) {
  log_message(LOG_LEVEL_DEBUG, "    Receiving n Data: %zu", data_size);
-  if (!session)
-    return false;
-  int fd = session->read_fd;
+  int fd = io_fd(io_read_fd, file_descriptor);

  struct timespec deadline;
  clock_gettime(CLOCK_MONOTONIC, &deadline);
@@ -241,15 +176,15 @@ bool protocol_receive_n_data(ProtocolSession* session, void* data, size_t data_s
      return false;

    ssize_t bytes_received;
-    if (session->ssl)
-      bytes_received = SSL_read(session->ssl, (char*)data + total_bytes_received,
-                                data_size - total_bytes_received);
+    if (io_ssl)
+      bytes_received =
+          SSL_read(io_ssl, (char*)data + total_bytes_received, data_size - total_bytes_received);
    else
      bytes_received =
          read(fd, (char*)data + total_bytes_received, data_size - total_bytes_received);
    if (bytes_received <= 0) {
-      if (session->ssl) {
-        int ssl_err = SSL_get_error(session->ssl, (int)bytes_received);
+      if (io_ssl) {
+        int ssl_err = SSL_get_error(io_ssl, (int)bytes_received);
        if (ssl_err == SSL_ERROR_WANT_WRITE || ssl_err == SSL_ERROR_WANT_READ) {
          wait_events = ssl_err == SSL_ERROR_WANT_WRITE ? POLLOUT : POLLIN;
          continue;
@@ -296,24 +231,24 @@ static const char* status_to_string(Status status) {
  }
 }

-bool protocol_send_str(ProtocolSession* session, const char* data) {
+bool send_str(int file_descriptor, const char* data) {
  if (data == NULL)
    return false;
  size_t size = strlen(data);
-  if (!protocol_send_n_data(session, &size, sizeof(size_t)))
+  if (!send_n_data(file_descriptor, &size, sizeof(size_t)))
    return false;
-  if (!protocol_send_n_data(session, data, size))
+  if (!send_n_data(file_descriptor, data, size))
    return false;
  log_message(LOG_LEVEL_DEBUG, "Send String: %s", data);
  return true;
 }

-char* protocol_receive_str(ProtocolSession* session) {
+char* receive_str(int file_descriptor) {
  size_t size;
-  if (!protocol_receive_n_data(session, &size, sizeof(size_t)))
+  if (!receive_n_data(file_descriptor, &size, sizeof(size_t)))
    return NULL;
  if (size > MAX_STRING_SIZE || size > SIZE_MAX - 1 ||
-      size + 1 > MAX_CONNECTION_MEMORY - session->total_allocated_bytes) {
+      size + 1 > MAX_CONNECTION_MEMORY - total_allocated_bytes) {
    log_message(LOG_LEVEL_ERROR, "String size %zu exceeds maximum %llu", size,
                (unsigned long long)MAX_STRING_SIZE);
    return NULL;
@@ -321,29 +256,29 @@ char* protocol_receive_str(ProtocolSession* session) {
  char* data = (char*)malloc(size + 1);
  if (data == NULL)
    return NULL;
-  if (!protocol_receive_n_data(session, data, size)) {
+  if (!receive_n_data(file_descriptor, data, size)) {
    free(data);
    return NULL;
  }
  data[size] = '\0';
-  session->total_allocated_bytes += size + 1;
+  total_allocated_bytes += size + 1;
  log_message(LOG_LEVEL_DEBUG, "Received String: %s", data);
  return data;
 }

-bool protocol_send_data(ProtocolSession* session, const Data* data) {
+bool send_data(int file_descriptor, const Data* data) {
  unsigned long long data_size = data->size;
-  if (!protocol_send_n_data(session, &data_size, sizeof(unsigned long long)))
+  if (!send_n_data(file_descriptor, &data_size, sizeof(unsigned long long)))
    return false;
-  if (!protocol_send_n_data(session, data->data, data_size))
+  if (!send_n_data(file_descriptor, data->data, data_size))
    return false;
  log_message(LOG_LEVEL_DEBUG, "Send %lld data", data_size);
  return true;
 }

-Data* protocol_receive_data(ProtocolSession* session) {
+Data* receive_data(int file_descriptor) {
  unsigned long long size = 0;
-  if (!protocol_receive_n_data(session, &size, sizeof(unsigned long long)))
+  if (!receive_n_data(file_descriptor, &size, sizeof(unsigned long long)))
    return NULL;
  if (size > MAX_DATA_PAYLOAD_SIZE) {
    log_message(LOG_LEVEL_ERROR, "Data size %llu exceeds maximum %llu", size,
@@ -351,86 +286,53 @@ Data* protocol_receive_data(ProtocolSession* session) {
    return NULL;
  }
  size_t allocation_size = size == 0 ? 1 : (size_t)size;
-  if (allocation_size > MAX_CONNECTION_MEMORY - session->total_allocated_bytes) {
+  if (allocation_size > MAX_CONNECTION_MEMORY - total_allocated_bytes) {
    log_message(LOG_LEVEL_ERROR, "Per-connection memory limit exceeded (%llu + %llu > %llu)",
-                (unsigned long long)session->total_allocated_bytes, size,
+                (unsigned long long)total_allocated_bytes, size,
                (unsigned long long)MAX_CONNECTION_MEMORY);
    return NULL;
  }
  void* data = malloc(allocation_size);
  if (data == NULL)
    return NULL;
-  if (!protocol_receive_n_data(session, data, (size_t)size)) {
+  if (!receive_n_data(file_descriptor, data, (size_t)size)) {
    free(data);
    return NULL;
  }
-  session->total_allocated_bytes += allocation_size;
+  total_allocated_bytes += allocation_size;
  log_message(LOG_LEVEL_DEBUG, "Received %lld data", size);
  Data* result = data_create(data, (size_t)size);
  if (!result) {
    free(data);
-    session->total_allocated_bytes -= allocation_size;
+    total_allocated_bytes -= allocation_size;
  }
  return result;
 }

-bool protocol_send_int(ProtocolSession* session, int data) {
-  if (!protocol_send_n_data(session, &data, sizeof(int)))
+bool send_int(int file_descriptor, int data) {
+  if (!send_n_data(file_descriptor, &data, sizeof(int)))
    return false;
  log_message(LOG_LEVEL_DEBUG, "Send Int: %d", data);
  return true;
 }

-bool protocol_receive_int(ProtocolSession* session, int* data) {
-  if (!protocol_receive_n_data(session, data, sizeof(int)))
+bool receive_int(int file_descriptor, int* data) {
+  if (!receive_n_data(file_descriptor, data, sizeof(int)))
    return false;
  log_message(LOG_LEVEL_DEBUG, "Received Int: %d", *data);
  return true;
 }

-bool protocol_send_status(ProtocolSession* session, Status status) {
-  if (!protocol_send_n_data(session, &status, sizeof(Status)))
+bool send_status(int file_descriptor, Status status) {
+  if (!send_n_data(file_descriptor, &status, sizeof(Status)))
    return false;
  log_message(LOG_LEVEL_DEBUG, "Send Status: %s", status_to_string(status));
  return true;
 }

-bool protocol_receive_status(ProtocolSession* session, Status* status) {
-  if (!protocol_receive_n_data(session, status, sizeof(Status)))
+bool receive_status(int file_descriptor, Status* status) {
+  if (!receive_n_data(file_descriptor, status, sizeof(Status)))
    return false;
  log_message(LOG_LEVEL_DEBUG, "Received Status: %s", status_to_string(*status));
  return true;
 }
-
-bool send_str(int fd, const char* data) {
-  (void)fd;
-  return protocol_send_str(legacy_session(), data);
-}
-char* receive_str(int fd) {
-  (void)fd;
-  return protocol_receive_str(legacy_session());
-}
-bool send_data(int fd, const Data* data) {
-  (void)fd;
-  return protocol_send_data(legacy_session(), data);
-}
-Data* receive_data(int fd) {
-  (void)fd;
-  return protocol_receive_data(legacy_session());
-}
-bool send_int(int fd, int data) {
-  (void)fd;
-  return protocol_send_int(legacy_session(), data);
-}
-bool receive_int(int fd, int* data) {
-  (void)fd;
-  return protocol_receive_int(legacy_session(), data);
-}
-bool send_status(int fd, Status status) {
-  (void)fd;
-  return protocol_send_status(legacy_session(), status);
-}
-bool receive_status(int fd, Status* status) {
-  (void)fd;
-  return protocol_receive_status(legacy_session(), status);
-}
@@ -19,23 +19,6 @@

 typedef struct ssl_st SSL;

-/*
- * Explicit owner of protocol I/O.  A session does not own the descriptors or
- * SSL object; it only describes the transport used by a transfer.  This makes
- * it safe to pass the transport to a worker without relying on inherited
- * thread-local state.
- */
-typedef struct ProtocolSession {
-  int read_fd;
-  int write_fd;
-  SSL* ssl;
-  unsigned long long bwlimit;
-  long long bw_tokens;
-  long long bw_last_refill_sec;
-  long bw_last_refill_nsec;
-  unsigned long long total_allocated_bytes;
-} ProtocolSession;
-
 typedef int Status;
 enum NET_STATUS {
  STATUS_OK,
@@ -56,23 +39,6 @@ void io_set_fds(int read_fd, int write_fd);
 void io_set_bwlimit(unsigned long long bytes_per_sec);
 void io_set_ssl(SSL* ssl);
 SSL* io_get_ssl(void);
-
-void protocol_session_init(ProtocolSession* session, int read_fd, int write_fd);
-/* Transitional bridge for helpers whose signatures still carry only an fd. */
-void protocol_session_bind(ProtocolSession* session);
-void protocol_session_unbind(void);
-void protocol_session_set_ssl(ProtocolSession* session, SSL* ssl);
-void protocol_session_set_bwlimit(ProtocolSession* session, unsigned long long bytes_per_sec);
-bool protocol_send_n_data(ProtocolSession* session, const void* data, size_t data_size);
-bool protocol_receive_n_data(ProtocolSession* session, void* data, size_t data_size);
-bool protocol_send_str(ProtocolSession* session, const char* data);
-char* protocol_receive_str(ProtocolSession* session);
-bool protocol_send_data(ProtocolSession* session, const Data* data);
-Data* protocol_receive_data(ProtocolSession* session);
-bool protocol_send_int(ProtocolSession* session, int data);
-bool protocol_receive_int(ProtocolSession* session, int* data);
-bool protocol_send_status(ProtocolSession* session, Status status);
-bool protocol_receive_status(ProtocolSession* session, Status* status);
 bool send_n_data(int file_descriptor, const void* data, size_t data_size);
 bool receive_n_data(int file_descriptor, void* data, size_t data_size);

@@ -173,7 +173,7 @@ Client* client_create() {
  return client;
 }

-bool tcp_connect_socket(Client* client, char* host, int port) {
+bool client_connect(Client* client, char* host, int port) {
  struct addrinfo hints;
  struct addrinfo* result;
  memset(&hints, 0, sizeof(hints));
@@ -222,12 +222,6 @@ bool tcp_connect_socket(Client* client, char* host, int port) {
    return false;
  }

-  return true;
-}
-
-bool client_connect(Client* client, char* host, int port) {
-  if (!tcp_connect_socket(client, host, port))
-    return false;
  tcp_apply_socket_timeout(client->file_descriptor);
  return true;
 }
@@ -30,7 +30,6 @@ void server_accept_loop(Server* server, void (*child_fn)(int, void*), void* chil
 void server_delete(Server** server);
 Client* client_create();
 bool client_connect(Client* client, char* host, int port);
-bool tcp_connect_socket(Client* client, char* host, int port);
 void client_disconnect(Client* client);
 void client_delete(Client* client);
 void tcp_set_timeouts(int timeout_sec, int contimeout_sec);
@@ -3,12 +3,15 @@
 #include "protocol.h"
 #include "transport_tcp.h"
 #include <arpa/inet.h>
+#include <netdb.h>
 #include <openssl/err.h>
 #include <openssl/ssl.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
 #include <unistd.h>

 bool tls_global_init(void) {
@@ -146,8 +149,53 @@ bool server_listen_tls(Server* server, void (*handler)(int file_descriptor)) {

 bool client_connect_tls(Client* client, char* host, int port, const char* cert_path,
                        const char* key_path, const char* ca_path) {
-  if (!tcp_connect_socket(client, host, port))
+  struct addrinfo hints;
+  struct addrinfo* result;
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_family = AF_UNSPEC;
+  hints.ai_socktype = SOCK_STREAM;
+  hints.ai_protocol = IPPROTO_TCP;
+
+  char port_str[16];
+  snprintf(port_str, sizeof(port_str), "%d", port);
+
+  int err = getaddrinfo(host, port_str, &hints, &result);
+  if (err != 0 || result == NULL) {
+    fprintf(stderr, "Could not resolve host: %s (%s)\n", host, gai_strerror(err));
    return false;
+  }
+
+  struct addrinfo* rp;
+  bool connected = false;
+  for (rp = result; rp != NULL; rp = rp->ai_next) {
+    if (client->file_descriptor >= 0)
+      close(client->file_descriptor);
+
+    client->file_descriptor = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+    if (client->file_descriptor < 0)
+      continue;
+
+    struct timeval ct;
+    ct.tv_sec = tcp_get_contimeout_sec();
+    ct.tv_usec = 0;
+    setsockopt(client->file_descriptor, SOL_SOCKET, SO_RCVTIMEO, &ct, sizeof(ct));
+    setsockopt(client->file_descriptor, SOL_SOCKET, SO_SNDTIMEO, &ct, sizeof(ct));
+
+    memcpy(&client->address, rp->ai_addr, rp->ai_addrlen);
+    client->address_length = rp->ai_addrlen;
+
+    if (connect(client->file_descriptor, (struct sockaddr*)&client->address,
+                client->address_length) == 0) {
+      connected = true;
+      break;
+    }
+  }
+  freeaddrinfo(result);
+
+  if (!connected) {
+    perror("Could not connect to Server!");
+    return false;
+  }

  SSL_CTX* ctx = create_ssl_ctx(false, cert_path, key_path, ca_path);
  if (!ctx)
@@ -237,10 +237,6 @@ bool has_path_traversal(const char* path) {
  return false;
 }

-bool utils_valid_batch_path(const char* path) {
-  return path && path[0] != '\0' && path[0] != '/' && !has_path_traversal(path);
-}
-
 char* path_cat(const char* path1, const char* path2) {
  if (path1 == NULL || *path1 == '\0')
    return str_dup(path2);
@@ -11,6 +11,5 @@ bool glob_match(const char* pattern, const char* str);
 bool delete_extras(const char* dest_root, ArrayList* manifest);
 void utils_set_authorized_root_fd(int fd);
 bool has_path_traversal(const char* path);
-bool utils_valid_batch_path(const char* path);

 #endif
@@ -1,5 +1,4 @@
 #include "test_client_cli.h"
-#include "client_validation.h"
 #include "config.h"
 #include "test_utils.h"
 #include "utils.h"
@@ -10,56 +9,6 @@
 /* Declaration of parse_args from client_cli.c */
 int parse_args(Config* config, int argc, char* argv[], int* positional_args, int* positional_count);

-static Config* valid_client_config() {
-  Config* cfg = config_create();
-  if (!cfg)
-    return NULL;
-  cfg->send_directory = str_dup("/src");
-  cfg->receive_root_directory = str_dup("/dst");
-  return cfg;
-}
-
-static void test_validate_config_required_paths() {
-  Config* cfg = config_create();
-  EXPECT_FALSE(validate_config(cfg));
-  cfg->send_directory = str_dup("/src");
-  EXPECT_FALSE(validate_config(cfg));
-  config_delete(cfg);
-}
-
-static void test_validate_config_incompatible_options() {
-  Config* cfg = valid_client_config();
-  cfg->use_sendfile = true;
-  cfg->use_compression = true;
-  EXPECT_FALSE(validate_config(cfg));
-  cfg->use_compression = false;
-  cfg->use_incremental = true;
-  cfg->use_chunk_serialization = true;
-  EXPECT_FALSE(validate_config(cfg));
-  config_delete(cfg);
-}
-
-static void test_validate_config_tls_requirements() {
-  Config* cfg = valid_client_config();
-  cfg->use_tls = true;
-  EXPECT_FALSE(validate_config(cfg));
-  cfg->tls_cert = str_dup("cert.pem");
-  EXPECT_FALSE(validate_config(cfg));
-  cfg->tls_key = str_dup("key.pem");
-  EXPECT_TRUE(validate_config(cfg));
-  config_delete(cfg);
-}
-
-static void test_validate_config_delta_sendfile_constraints() {
-  Config* cfg = valid_client_config();
-  cfg->use_delta = true;
-  EXPECT_FALSE(validate_config(cfg));
-  cfg->use_incremental = true;
-  cfg->use_sendfile = true;
-  EXPECT_FALSE(validate_config(cfg));
-  config_delete(cfg);
-}
-
 /* Test main() with --help flag (early return path, no server connection needed) */
 static void test_cli_help() {
  /* We can't easily call main() because it calls send_files which needs a server.
@@ -338,10 +287,6 @@ static void test_parse_args_archive() {
 }

 void test_client_cli() {
-  test_validate_config_required_paths();
-  test_validate_config_incompatible_options();
-  test_validate_config_tls_requirements();
-  test_validate_config_delta_sendfile_constraints();
  test_cli_help();
  test_cli_archive_flags();
  test_cli_dry_run();
@@ -224,26 +224,6 @@ static void test_config_send_receive_version_mismatch() {
  }
 }

-static void test_config_receive_truncated() {
-  int p[2];
-  EXPECT_EQ_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, p), 0);
-  io_set_fds(p[0], p[0]);
-  io_set_bwlimit(0);
-
-  /* A valid prefix exercises cleanup after allocated wire strings and a
-   * partially received scalar field. */
-  EXPECT_TRUE(send_str(p[1], PROTOCOL_VERSION));
-  EXPECT_TRUE(send_str(p[1], "/src"));
-  EXPECT_TRUE(send_str(p[1], "/dst"));
-  EXPECT_TRUE(send_int(p[1], 1));
-  shutdown(p[1], SHUT_WR);
-
-  const Config* cfg = config_receive(p[0]);
-  EXPECT_NULL(cfg);
-  close(p[0]);
-  close(p[1]);
-}
-
 static void test_is_remote_dest() {
  /* Valid SSH-style destinations */
  EXPECT_TRUE(is_remote_dest("user@host:/path"));
@@ -276,7 +256,6 @@ void test_config() {
  if (!is_running_under_valgrind()) {
    test_config_send_receive();
    test_config_send_receive_version_mismatch();
-    test_config_receive_truncated();
  }
  test_is_remote_dest();
 }
@@ -38,23 +38,6 @@ static void test_send_receive_n_data_zero() {
  close(p[1]);
 }

-static void test_explicit_session_context() {
-  int p[2];
-  EXPECT_EQ_INT(pipe(p), 0);
-  ProtocolSession session;
-  protocol_session_init(&session, p[0], p[1]);
-  protocol_session_set_bwlimit(&session, 0);
-
-  const char payload[] = "explicit context";
-  char received[sizeof(payload)] = {0};
-  EXPECT_TRUE(protocol_send_n_data(&session, payload, sizeof(payload)));
-  EXPECT_TRUE(protocol_receive_n_data(&session, received, sizeof(received)));
-  EXPECT_EQ_INT(memcmp(payload, received, sizeof(payload)), 0);
-
-  close(p[0]);
-  close(p[1]);
-}
-
 static void test_send_receive_str() {
  int p[2];
  EXPECT_EQ_INT(pipe(p), 0);
@@ -190,7 +173,6 @@ static void test_receive_str_truncated() {
 void test_protocol() {
  test_send_receive_n_data();
  test_send_receive_n_data_zero();
-  test_explicit_session_context();
  test_send_receive_str();
  test_send_receive_str_normal();
  test_send_receive_data();
@@ -11,7 +11,11 @@
 #include <sys/wait.h>
 #include <unistd.h>

-#include "receiver.h"
+/* Include server.c but rename main to avoid conflict with test runner's main */
+#define main server_main_
+#define FASTSYNC_SERVER_AS_LIB
+#include "server.c"
+#undef main

 /* Test receive_files with immediate FINISHED status */
 static void test_receive_files_finished() {
@@ -32,7 +36,7 @@ static void test_receive_files_finished() {
    /* Child: use p[0] for both read and write */
    close(p[1]);
    io_set_fds(p[0], p[0]);
-    int ret = receiver_receive_files(cfg, p[0]);
+    int ret = receive_files(cfg, p[0]);
    close(p[0]);
    config_delete(cfg);
    _exit(ret == 0 ? 0 : 1);
@@ -84,7 +88,7 @@ static void test_receive_files_single_file() {
    /* Child: use p[0] for both read and write */
    close(p[1]);
    io_set_fds(p[0], p[0]);
-    int ret = receiver_receive_files(cfg, p[0]);
+    int ret = receive_files(cfg, p[0]);
    close(p[0]);
    config_delete(cfg);
    _exit(ret == 0 ? 0 : 1);
@@ -145,7 +149,7 @@ static void test_receive_files_abort() {
  if (pid == 0) {
    close(p[1]);
    io_set_fds(p[0], p[0]);
-    int ret = receiver_receive_files(cfg, p[0]);
+    int ret = receive_files(cfg, p[0]);
    close(p[0]);
    config_delete(cfg);
    /* Should return -1 on abort */
Author	SHA1	Message	Date
TapTap	0c24136052	Merge pull request 'docs: clarify rsync compatibility roadmap' (#215 ) from docs/rsync-compatible-readme-clean into dev CI / lint (push) Successful in 34s Details CI / sanitizers (address) (push) Successful in 35s Details CI / sanitizers (undefined) (push) Successful in 35s Details CI / fuzz-build (push) Successful in 15s Details CI / build-and-test (push) Successful in 1m15s Details CI / coverage (push) Successful in 31s Details CI / valgrind (push) Successful in 33s Details Reviewed-on: #215	2026-08-15 13:48:01 +02:00
TapTap	d19fc68803	Merge branch 'dev' into docs/rsync-compatible-readme-clean CI / lint (pull_request) Successful in 33s Details CI / sanitizers (address) (pull_request) Successful in 36s Details CI / sanitizers (undefined) (pull_request) Successful in 36s Details CI / fuzz-build (pull_request) Successful in 15s Details CI / coverage (pull_request) Successful in 32s Details CI / build-and-test (pull_request) Successful in 1m16s Details CI / valgrind (pull_request) Successful in 33s Details	2026-08-15 13:47:55 +02:00
TapTap	6b7213db5c	docs: align compatibility guidance CI / lint (pull_request) Failing after 2s Details CI / build-and-test (pull_request) Has been skipped Details CI / sanitizers (address) (pull_request) Has been skipped Details CI / sanitizers (undefined) (pull_request) Has been skipped Details CI / fuzz-build (pull_request) Has been skipped Details CI / coverage (pull_request) Has been skipped Details CI / valgrind (pull_request) Has been skipped Details	2026-08-15 13:41:23 +02:00
TapTap	de537810e5	docs: fix server destination root examples CI / lint (pull_request) Failing after 2s Details CI / build-and-test (pull_request) Has been skipped Details CI / sanitizers (address) (pull_request) Has been skipped Details CI / sanitizers (undefined) (pull_request) Has been skipped Details CI / fuzz-build (pull_request) Has been skipped Details CI / coverage (pull_request) Has been skipped Details CI / valgrind (pull_request) Has been skipped Details	2026-08-15 13:14:28 +02:00
TapTap	def58554d9	docs: clarify rsync compatibility roadmap CI / lint (pull_request) Failing after 2s Details CI / build-and-test (pull_request) Has been skipped Details CI / sanitizers (address) (pull_request) Has been skipped Details CI / sanitizers (undefined) (pull_request) Has been skipped Details CI / fuzz-build (pull_request) Has been skipped Details CI / coverage (pull_request) Has been skipped Details CI / valgrind (pull_request) Has been skipped Details	2026-08-15 12:54:38 +02:00
TapTap	41b624db5a	Merge pull request 'fix: satisfy clang-format in CLI test' (#211 ) from fix/dev-ci-clang-format into dev CI / lint (push) Successful in 34s Details CI / sanitizers (address) (push) Successful in 37s Details CI / sanitizers (undefined) (push) Successful in 37s Details CI / fuzz-build (push) Successful in 14s Details CI / coverage (push) Successful in 31s Details CI / build-and-test (push) Successful in 1m16s Details CI / valgrind (push) Successful in 34s Details Reviewed-on: #211	2026-08-15 11:55:41 +02:00