.opencode/agents/integrator.md

@@ -116,7 +116,7 @@ The project uses Gitea Actions. Key jobs:
 jobs:
   new-job:
     runs-on: ubuntu-latest
-    container: gitea.tap-tap.win/taptap/fastsync-ci:v10
+    container: gitea.tap-tap.win/taptap/fastsync-ci:v11
     steps:
       - uses: actions/checkout@v4
       - name: Configure

Dockerfile

@@ -12,7 +12,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 # rsync is used as the reference implementation for drop-in parity tests.
 # Ubuntu 24.04 ships 3.2.7, so build the pinned 3.4.1 reference from source.
 ARG RSYNC_VERSION=3.4.1
+ARG RSYNC_SHA256=2924bcb3a1ed8b551fc101f740b9f0fe0a202b115027647cf69850d65fd88c52
 RUN curl -fsSL "https://download.samba.org/pub/rsync/src/rsync-${RSYNC_VERSION}.tar.gz" -o /tmp/rsync.tar.gz && \
+    echo "${RSYNC_SHA256}  /tmp/rsync.tar.gz" | sha256sum -c - && \
     tar -xzf /tmp/rsync.tar.gz -C /tmp && \
     cd "/tmp/rsync-${RSYNC_VERSION}" && \
     ./configure --enable-zstd --enable-xxhash --enable-lz4 && \

src/client/client_cli.c

@@ -132,16 +132,20 @@ static int set_positive_int_option(int* dest, const char* value, const char* opt
  * zstd choice; any other rsync choice is rejected by name instead of being
  * silently accepted and ignored. */
 static int set_compression_choice(Config* config, const char* value) {
-  if (strcmp(value, "zstd") != 0 && strcmp(value, "none") != 0 && strcmp(value, "auto") != 0) {
+  /* rsync's "auto" is normalized to the canonical "zstd" at parse time (like
+     --checksum-choice=auto), so the value that crosses the wire is always one
+     the receiver accepts. */
+  const char* canonical = strcmp(value, "auto") == 0 ? "zstd" : value;
+  if (strcmp(canonical, "zstd") != 0 && strcmp(canonical, "none") != 0) {
     log_message(LOG_LEVEL_ERROR,
                 "--compress-choice '%s' is not implemented; FastSync supports zstd, none or auto "
                 "(rsync's lz4/zlib/zlibx are rejected, never silently ignored)",
                 value);
     return -1;
   }
-  if (set_string_option(&config->compress_choice, value, "--compress-choice") != 0)
+  if (set_string_option(&config->compress_choice, canonical, "--compress-choice") != 0)
     return -1;
-  config->use_compression = strcmp(value, "none") != 0;
+  config->use_compression = strcmp(canonical, "none") != 0;
   return 0;
 }
 
@@ -1992,11 +1996,6 @@ static bool cli_handle_remote_basis_options(CliParseCtx* ctx) {
       ctx->exit_code = -1;
     return true;
   }
-  if (strncmp(arg, "-M=", 3) == 0) {
-    if (config_add_remote_option(config, arg + 3, "-M") != 0)
-      ctx->exit_code = -1;
-    return true;
-  }
   if (opt_is(arg, "--remote-option", "-M")) {
     if (ctx->i + 1 >= ctx->argc) {
       log_message(LOG_LEVEL_ERROR, "missing argument for --remote-option");
@@ -2271,10 +2270,12 @@ static int cli_finalize_config(Config* config, bool verbose, bool no_delta, bool
    * --no-xattrs/--no-acls negation) so the sender's wire gate always matches
    * the flags the receiver will recompute from the received config. */
   config->use_xattrs = config->preserve_acls || config->preserve_xattrs;
-  /* Output parity: -i/--itemize-changes and --out-format need the pre-transfer
+  /* Output parity: -i/--itemize-changes, --out-format and --log-file-format
-   * destination snapshot (new vs modified and which attributes differ), so ask
+   * need the pre-transfer destination snapshot (new vs modified and which
-   * the receiver to report it on every per-file check.  This is a wire field. */
+   * attributes differ), so ask the receiver to report it on every per-file
-  config->report_dest_info = config->itemize_changes || config->out_format != NULL;
+   * check.  This is a wire field. */
+  config->report_dest_info = config->itemize_changes || config->out_format != NULL ||
+                             (config->log_file != NULL && config->log_file_format != NULL);
   return 0;
 }
 
@@ -2306,7 +2307,7 @@ static bool cli_long_takes_separate_value(const char* arg) {
       "--checksum-choice", "--cc",           "--checksum-seed", "--sockopts",
       "--remote-option",   "--compare-dest", "--copy-dest",     "--link-dest",
       "--usermap",         "--groupmap",     "--chown",         "--copy-as",
-      "--outbuf",          "--debug",        "--info",
+      "--outbuf",          "--debug",        "--info",          "--skip-compress",
   };
   for (size_t i = 0; i < sizeof(extra) / sizeof(extra[0]); i++)
     if (strcmp(arg, extra[i]) == 0)

src/client/client_send.c

@@ -908,8 +908,10 @@ static int send_list_only(const Config* config) {
       entries = calloc(capacity, sizeof(ListEntry));
       if (entries == NULL) {
         oom = true;
+      } else if ((entries[0].name = str_dup("")) == NULL) {
+        /* A NULL name would be dereferenced by qsort/render: fail the listing. */
+        oom = true;
       } else {
-        entries[0].name = str_dup("");
         entries[0].mode = st.st_mode;
         entries[0].mtime = st.st_mtime;
         entries[0].mtime_nsec = st.st_mtim.tv_nsec;
@@ -1015,15 +1017,18 @@ static int send_list_only(const Config* config) {
   return 0;
 }
 
-/* Send the delete manifest (keep-set paths plus the protected excluded
+/* Send the delete manifest to the server.  Returns 0 on success, -1 on
-   prefixes and the --delete-missing-args exact-delete paths) to the server.
+   failure.  It carries FOUR sections: the keep-set paths, the protected
-   Returns 0 on success, -1 on failure.  When --delete-excluded is given
+   excluded prefixes, the --delete-missing-args exact-delete paths, and the
-   `protected` is empty: excluded destination mirrors are then ordinary extras
+   destination-relative directories the sender synchronized this run.
-   and are removed.  When --delete-missing-args is active `missing_args` holds
+   When --delete-excluded is given `protected` is empty: excluded destination
-   the destination mirrors of missing --files-from entries: each is an explicit
+   mirrors are then ordinary extras and are removed.  When
-   receiver-side deletion request, independent of the extras walk.  A NULL
+   --delete-missing-args is active `missing_args` holds the destination mirrors
-   keep-set / protected / missing list transmits an empty section.  All three
+   of missing --files-from entries: each is an explicit receiver-side deletion
-   sections are unbounded on the sender; the receiver enforces
+   request, independent of the extras walk.  `synced_dirs` confines the extras
+   walk to entries directly inside a synchronized directory.  A NULL
+   keep-set / protected / missing / dirs list transmits an empty section.  All
+   four sections are unbounded on the sender; the receiver enforces
    MAX_MANIFEST_ENTRIES per section and a single MAX_MANIFEST_BYTES budget
    shared across the sections, rejecting (with STATUS_ERROR) an over-budget
    frame.  A heavily filtered source whose exclusion list is large therefore

src/client/scanner.c

@@ -1120,18 +1120,23 @@ Chunk* directory_scanner_next(DirectoryScanner* scanner) {
     if (inspection == 0) {
       /* A user-selection exclude protects its destination mirror from --delete
          unless --delete-excluded; a size prune is always protected.  Other
-         skips (unreadable, symlink policy) protect nothing. */
+         skips (unreadable, symlink policy) protect nothing.  Under -R +
+         --files-from the protected prefix must be the entry's bare relative
+         wire path, not its source path (which would not match the destination
+         layout and would leave the mirror deletable). */
       if (inspected.excluded) {
-        char* abs_path = path_cat(scanner->current_path, entry->d_name);
+        char* protected_path = scanner->relative_mode
-        if (!abs_path) {
+                                   ? child_rel_path(scanner->current_rel, entry->d_name)
+                                   : path_cat(scanner->current_path, entry->d_name);
+        if (!protected_path) {
           scanner->failed = true;
           break;
         }
         if (inspected.size_excluded)
-          scanner_record_size_skipped(scanner, abs_path);
+          scanner_record_size_skipped(scanner, protected_path);
         else
-          scanner_record_excluded(scanner, abs_path);
+          scanner_record_excluded(scanner, protected_path);
-        free(abs_path);
+        free(protected_path);
       }
       continue;
     }
@@ -1510,17 +1515,23 @@ static void scan_root_entry(const ScannerOptions* options, const FilterNode* roo
     if (inspected.excluded)
       sink = inspected.size_excluded ? options->size_skipped_paths : options->excluded_paths;
     if (sink) {
-      /* A root-level prune protects the destination mirror of the same-named
+      /* A root-level prune protects the destination mirror of the entry's wire
-         wire path (at the root the bare name is the wire path in every
+         path: under -R + --files-from that is the bare relative name, otherwise
-         layout). */
+         it is the full source path with a leading '/' removed (matching the
-      char* abs_path = path_cat(root_directory, entry->d_name);
+         send_path/file_wire_path the scanner hands the sender). */
-      if (!abs_path) {
+      if (options->relative && options->file_list != NULL) {
-        ps->failed = true;
+        if (!excluded_sink_append(sink, options->excluded_mutex, entry->d_name))
-      } else {
-        const char* rel = *abs_path == '/' ? abs_path + 1 : abs_path;
-        if (!excluded_sink_append(sink, options->excluded_mutex, rel))
           ps->failed = true;
-        free(abs_path);
+      } else {
+        char* abs_path = path_cat(root_directory, entry->d_name);
+        if (!abs_path) {
+          ps->failed = true;
+        } else {
+          const char* rel = *abs_path == '/' ? abs_path + 1 : abs_path;
+          if (!excluded_sink_append(sink, options->excluded_mutex, rel))
+            ps->failed = true;
+          free(abs_path);
+        }
       }
     }
     return;

src/server/server.c

@@ -752,10 +752,11 @@ void handler(int file_descriptor) {
   protocol_set_8_bit_output(config->eight_bit_output);
   /* Server-side per-message protocol deadline for every frame from here on.
    * `timeout` is not serialized, so this is the server's own config (the server
-   * has no --timeout CLI and defaults it to 0): the built-in 60 s window stays
+   * has no --timeout CLI and defaults it to 0).  A client's --timeout tightens
-   * in effect.  A client's --timeout tightens only that client's own protocol
+   * only that client's own protocol I/O; the server floors its own deadline at
-   * I/O and the server's socket read/write timeout is the transport default. */
+   * SERVER_IO_TIMEOUT_SEC so a silent peer can never hold a session slot
-  protocol_session_set_io_timeout(&session, config->timeout);
+   * forever (the socket layer gets the same floor at startup). */
+  protocol_session_set_io_timeout(&session, protocol_server_io_timeout_sec(config->timeout));
   const char* authorized_root = utils_get_authorized_root_path();
   if (!authorized_root) {
     log_message(LOG_LEVEL_ERROR, "No server-side destination root configured");
@@ -904,7 +905,8 @@ void handler(int file_descriptor) {
       goto done;
     }
     protocol_session_set_max_alloc(&context->session, config->max_alloc);
-    protocol_session_set_io_timeout(&context->session, config->timeout);
+    protocol_session_set_io_timeout(&context->session,
+                                    protocol_server_io_timeout_sec(config->timeout));
     atomic_store(&context->session.total_allocated_bytes,
                  atomic_load(&session.total_allocated_bytes));
     pipeline_context_receiver_set_queue_byte_limit(context, RECEIVER_QUEUE_MAX_BYTES);
@@ -1220,6 +1222,10 @@ int main(int argc, char* argv[]) {
   server_iconv_spec = opts.iconv_spec;
   signal(SIGINT, cleanup);
   signal(SIGTERM, cleanup);
+  /* Server-owned socket deadline floor: the client default --timeout=0 would
+   * otherwise leave accepted sockets without SO_RCVTIMEO/SO_SNDTIMEO and let a
+   * silent peer hold a connection (and its process slot) forever. */
+  tcp_set_timeouts(SERVER_IO_TIMEOUT_SEC, SERVER_IO_TIMEOUT_SEC);
 
   if (opts.stdio_mode) {
     /* SSH authenticates the stdio transport outside of FastSync. */

src/shared/config.c

@@ -46,9 +46,11 @@ static void config_set_defaults(Config* config) {
   config->server_port_set = false;
   config->server_host_set = false;
   /* rsync defaults: --timeout=0 (I/O timeouts disabled) and --contimeout=60.
-   * A value of 0 disables the deadline on both the socket layer
+   * A value of 0 disables the client's own deadline on both the socket layer
    * (tcp_set_timeouts) and the protocol layer
-   * (protocol_session_set_io_timeout); a positive value sets it. */
+   * (protocol_session_set_io_timeout); a positive value sets it.  A server
+   * session floors the deadline at SERVER_IO_TIMEOUT_SEC so 0 can never hold a
+   * connection open forever. */
   config->timeout = 0;
   config->contimeout = 60;
   config->quiet = false;
@@ -207,7 +209,8 @@ static bool validate_received_config(const Config* config) {
          config->delta_block_size >= DELTA_BLOCK_SIZE_MIN &&
          config->delta_block_size <= DELTA_BLOCK_SIZE_MAX &&
          config->delta_max_file_size <= DELTA_MAX_FILE_SIZE && config->modify_window >= 0 &&
-         config->max_delete >= -1 && config->skip_compress_count >= 0 &&
+         config->max_delete >= -1 && config->max_alloc <= MAX_SERVER_ALLOC &&
+         config->skip_compress_count >= 0 &&
          config->skip_compress_count <= MAX_SKIP_COMPRESS_SUFFIXES &&
          (!config->chmod_spec || !*config->chmod_spec ||
           chmod_apply(0, config->chmod_spec, &(mode_t){0})) &&
@@ -788,13 +791,14 @@ void config_delete(Config* config) {
  * ------------------------------------------------------------------------- */
 
 /* --max-alloc: raw 64-bit value, clamped server-side and installed as the
- * session allocation ceiling.  Zero means "no alloc limit" (rsync's
+ * session allocation ceiling.  A received 0 is rsync's "no alloc limit"; on the
- * --max-alloc=0) and is passed through; a non-zero value is clamped to the
+ * receive path it is mapped to the server ceiling so a client can never disable
- * server's own ceiling. */
+ * it (client-side 0 remains unlimited).  Any value above the ceiling is clamped
+ * to it. */
 static bool config_receive_max_alloc(int fd, unsigned long long* value) {
   if (!receive_n_data(fd, value, sizeof(*value)))
     return false;
-  if (*value > MAX_SERVER_ALLOC)
+  if (*value == 0 || *value > MAX_SERVER_ALLOC)
     *value = MAX_SERVER_ALLOC;
   protocol_session_set_max_alloc(NULL, *value);
   return true;
@@ -1362,7 +1366,8 @@ Config* config_receive_with_validate(int file_descriptor, ConfigValidateFunc val
       !receive_output_options(file_descriptor, config, &budget))
     goto error;
   if (config->compress_choice[0] != '\0' && strcmp(config->compress_choice, "zstd") != 0 &&
-      strcmp(config->compress_choice, "none") != 0) {
+      strcmp(config->compress_choice, "none") != 0 &&
+      strcmp(config->compress_choice, "auto") != 0) {
     char* escaped_choice = output_escape(config->compress_choice, config->eight_bit_output);
     log_message(LOG_LEVEL_ERROR, "Unsupported compression choice: %s",
                 escaped_choice ? escaped_choice : "<allocation failed>");
@@ -1373,6 +1378,15 @@ Config* config_receive_with_validate(int file_descriptor, ConfigValidateFunc val
     free(escaped_choice);
     goto error;
   }
+  /* Defensive: an older/hostile client may still send "auto"; canonicalize it
+     to zstd (its effective choice) so the stored value is always concrete. */
+  if (strcmp(config->compress_choice, "auto") == 0) {
+    char* canonical = str_dup("zstd");
+    if (!canonical)
+      goto error;
+    free(config->compress_choice);
+    config->compress_choice = canonical;
+  }
   if (!validate_received_config(config)) {
     log_message(LOG_LEVEL_ERROR, "Invalid configuration received from client");
     send_error_detail(file_descriptor, "invalid configuration received from client");

src/shared/config.h

@@ -328,9 +328,10 @@ typedef struct Config {
   char* tls_key;
   char* tls_ca;
   /* --timeout: per-message I/O deadline in seconds.  0 (rsync's default)
-   * disables the deadline entirely on both the socket layer and the protocol
+   * disables the deadline entirely on the client's own socket and protocol
-   * layer; a positive value sets it.  See protocol_session_set_io_timeout and
+   * layers; a positive value sets it.  A server session never inherits the
-   * tcp_set_timeouts. */
+   * disabled value: it applies the SERVER_IO_TIMEOUT_SEC floor (see
+   * protocol_server_io_timeout_sec and tcp_set_timeouts). */
   int timeout;
   /* --contimeout: connect()/accept timeout in seconds (rsync's default 60);
    * 0 disables it.  Transport layer only. */

src/shared/file.c

@@ -182,6 +182,7 @@ File* file_create(const char* path) {
   file->rdev_major = 0;
   file->rdev_minor = 0;
   file->xattrs = NULL;
+  file->dest_state = (OutputDestState){0};
   return file;
 }
 

src/shared/file_receive.c

@@ -295,12 +295,17 @@ static FileSaveResult file_save_hardlink_sibling(const char* root_directory, con
     free(destination_path);
     return absent_result;
   }
-  /* Resolve a relative --temp-dir against the destination root, exactly as the
+  /* Resolve a relative --temp-dir under the destination root, exactly as the
-   * primary save path does; an absolute one is used verbatim. */
+   * primary save path does; an absolute or `..`-escaping value is rejected. */
   char* resolved_temp = NULL;
   if (cfg->temp_dir) {
-    resolved_temp =
+    if (cfg->temp_dir[0] == '/' || has_path_traversal(cfg->temp_dir)) {
-        cfg->temp_dir[0] == '/' ? str_dup(cfg->temp_dir) : path_cat(root_directory, cfg->temp_dir);
+      free(content);
+      free(first_disk);
+      free(destination_path);
+      return FILE_SAVE_ERROR;
+    }
+    resolved_temp = path_cat(root_directory, cfg->temp_dir);
     if (!resolved_temp) {
       free(content);
       free(first_disk);
@@ -772,15 +777,16 @@ FileSaveResult file_save_to_disk_full(const char* root_directory, const File* fi
     return file_save_hardlink_sibling(root_directory, file, config);
   }
 
-  /* These options arrive from the client.  --backup-dir and --partial-dir are
+  /* These options arrive from the client.  --backup-dir, --partial-dir and
-     names below the server root, never independent filesystem roots: an
+     --temp-dir are names below the server root, never independent filesystem
-     absolute or `..`-escaping value is rejected outright.  --temp-dir is
+     roots: an absolute or `..`-escaping value is rejected outright (rsync's
-     deliberately NOT confined: rsync accepts any temp dir (absolute, or
+     daemon confines temp-dir to the module the same way).  A relative temp dir
-     relative to the destination root), including one outside the destination
+     is resolved under the receive root below; if that resolution still lands on
-     tree or on another filesystem, and falls back to a non-atomic copy when
+     a different filesystem than the destination the install falls back to a
-     the install rename hits EXDEV. */
+     non-atomic copy (see file_to_disk_secure_impl), never an abort. */
   if ((backup_dir && (backup_dir[0] == '/' || has_path_traversal(backup_dir))) ||
-      (partial_dir && (partial_dir[0] == '/' || has_path_traversal(partial_dir))))
+      (partial_dir && (partial_dir[0] == '/' || has_path_traversal(partial_dir))) ||
+      (temp_dir && (temp_dir[0] == '/' || has_path_traversal(temp_dir))))
     return FILE_SAVE_ERROR;
   if (backup_dir && !(confined_backup = path_cat(root_directory, backup_dir)))
     return FILE_SAVE_ERROR;
@@ -906,20 +912,16 @@ FileSaveResult file_save_to_disk_full(const char* root_directory, const File* fi
 
   /* A configured --temp-dir sends the temporary working copy to a scratch
      directory; the engine then atomically renames the completed file into the
-     final destination directory.  rsync resolves a relative temp dir against
+     final destination directory.  A relative temp dir is resolved under the
-     the destination directory and uses an absolute one verbatim, requiring
+     receive root and must already exist (an absolute or `..`-escaping value was
-     that it already exist; the engine falls back to a non-atomic copy on
+     rejected above); the engine falls back to a non-atomic copy on EXDEV.  The
-     EXDEV.  The partial-dir flow already keeps its working copy in a separate
+     partial-dir flow already keeps its working copy in a separate directory and
-     directory and --inplace writes directly, so neither diverts through the
+     --inplace writes directly, so neither diverts through the scratch dir
-     scratch dir (matching rsync, where --inplace/--partial-dir supersede
+     (matching rsync, where --inplace/--partial-dir supersede --temp-dir). */
-     --temp-dir). */
   char* confined_temp = NULL;
   bool use_temp_dir = temp_dir != NULL && !inplace && !use_partial_root;
   if (use_temp_dir) {
-    if (temp_dir[0] == '/')
+    confined_temp = path_cat(root_directory, temp_dir);
-      confined_temp = str_dup(temp_dir);
-    else
-      confined_temp = path_cat(root_directory, temp_dir);
     if (!confined_temp)
       goto fail;
     /* A user-supplied trailing slash would leave the scratch path ending in
@@ -3061,8 +3063,15 @@ static bool delete_extras_budgeted(const Config* config, DeleteManifest* manifes
       idx++;
     }
   }
-  size_t remaining =
+  /* Clamp rather than subtract: an accounting bug where deleted already exceeds
-      budget->max_delete == SIZE_MAX ? SIZE_MAX : budget->max_delete - budget->deleted;
+     max_delete must never underflow into an effectively unlimited budget. */
+  size_t remaining;
+  if (budget->max_delete == SIZE_MAX)
+    remaining = SIZE_MAX;
+  else if (budget->deleted >= budget->max_delete)
+    remaining = 0;
+  else
+    remaining = budget->max_delete - budget->deleted;
   size_t deleted = 0;
   size_t skipped = 0;
   DeleteWalkResult result =
@@ -3195,7 +3204,11 @@ static bool delete_missing_args_budgeted(const Config* config, DeleteManifest* m
              parity); the now-empty directory itself costs one more.  A run that
              hits the cap leaves the remaining entries in place. */
           ArrayList* no_keeps = array_list_create(free);
-          size_t remaining = budget->max_delete - budget->deleted;
+          /* Never let an accounting slip (deleted > max_delete) underflow the
+             remaining budget into SIZE_MAX, which would grant unlimited
+             deletions. */
+          size_t remaining =
+              budget->deleted >= budget->max_delete ? 0 : budget->max_delete - budget->deleted;
           size_t contents_deleted = 0;
           size_t contents_skipped = 0;
           DeleteWalkResult walk =
@@ -3214,7 +3227,8 @@ static bool delete_missing_args_budgeted(const Config* config, DeleteManifest* m
             budget->limit_hit = true;
             budget->skipped++;
           } else if (file_remove_tree_secure(full)) {
-            budget->deleted++;
+            /* The shared `if (removed)` tail charges this directory exactly
+               once; counting it here too would consume two budget units. */
             removed = true;
           } else {
             ok = false;

src/shared/protocol.c

@@ -104,6 +104,10 @@ int protocol_get_io_timeout_sec(void) {
   return session->io_timeout_sec > 0 ? session->io_timeout_sec : 0;
 }
 
+int protocol_server_io_timeout_sec(int client_timeout) {
+  return client_timeout > 0 ? client_timeout : SERVER_IO_TIMEOUT_SEC;
+}
+
 void protocol_session_set_max_alloc(ProtocolSession* session, unsigned long long max_alloc) {
   if (!session)
     session = bound_session ? bound_session : &legacy_io_session;
@@ -495,6 +499,8 @@ static const char* status_to_string(Status status) {
     return "ERROR_DETAIL";
   case STATUS_DRY_RUN_TRANSFER:
     return "DRY_RUN_TRANSFER";
+  case STATUS_DELETE_LIMIT:
+    return "DELETE_LIMIT";
   case STATUS_DEST_INFO:
     return "DEST_INFO";
   default:

src/shared/protocol.h

@@ -34,6 +34,11 @@
 #define DEFAULT_MAX_ALLOC (1ULL * 1024 * 1024 * 1024)
 /* Server policy ceiling for a client-provided allocation limit. */
 #define MAX_SERVER_ALLOC (256ULL * 1024 * 1024)
+/* Server-owned floor for the per-message I/O deadline.  A client --timeout=0
+   (rsync's default) disables the client's own deadlines, but a server session
+   must never be held open forever by a silent peer (slow-loris), so the server
+   floors the effective deadline at this value. */
+#define SERVER_IO_TIMEOUT_SEC 60
 /* Bounded cumulative per-connection receive budget.  In-flight wire buffers,
    decompression buffers and queued (not yet written) file payloads for a
    connection must stay within this ceiling. */
@@ -59,10 +64,12 @@ typedef struct ProtocolSession {
   bool eight_bit_output;
   unsigned long long max_alloc;
   /* Per-session deadline (seconds) applied to every protocol send/receive by
-   * protocol_send_n_data / protocol_receive_n_data.  Defaults to the built-in
+   * protocol_send_n_data / protocol_receive_n_data.  The initialized default is
-   * 60 s window; a value <= 0 falls back to that default.  Set from the
+   * the built-in 60 s window; a value <= 0 disables the deadline (rsync's
-   * negotiated Config->timeout so --timeout is honored by the poll()-driven
+   * --timeout=0).  Set from the negotiated Config->timeout so --timeout is
-   * protocol I/O, not just the socket SO_RCVTIMEO/SO_SNDTIMEO. */
+   * honored by the poll()-driven protocol I/O, not just the socket
+   * SO_RCVTIMEO/SO_SNDTIMEO.  The server does not propagate a client 0 here: it
+   * installs protocol_server_io_timeout_sec() so its sessions keep a floor. */
   int io_timeout_sec;
 } ProtocolSession;
 
@@ -189,15 +196,20 @@ 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);
 void protocol_session_set_max_alloc(ProtocolSession* session, unsigned long long max_alloc);
-/* Override the per-message send/receive deadline for this session.
+/* Override the per-message send/receive deadline for this session.  The value
- * `sec` <= 0 restores the built-in 60 s default (used for --timeout=0/unset).
+ * is stored verbatim: a positive value sets the deadline, `sec` <= 0 disables
- * An explicit long deadline (e.g. the delete-ack wait) is applied per-call by
+ * it (rsync's --timeout=0).  An explicit long deadline (e.g. the delete-ack
- * protocol_receive_status_timed and is unaffected by this setter. */
+ * wait) is applied per-call by protocol_receive_status_timed and is unaffected
+ * by this setter. */
 void protocol_session_set_io_timeout(ProtocolSession* session, int sec);
-/* Effective per-message I/O deadline (seconds) for the currently-bound session,
+/* Effective per-message I/O deadline (seconds) for the currently-bound session.
- * falling back to the built-in default.  Used by the plaintext sendfile path
+ * Zero means the deadline is disabled (rsync's --timeout=0).  Used by the
- * which bypasses the protocol send primitive. */
+ * plaintext sendfile path which bypasses the protocol send primitive. */
 int protocol_get_io_timeout_sec(void);
+/* The server-side effective deadline for a client-requested timeout: a positive
+ * client value is honored, otherwise the SERVER_IO_TIMEOUT_SEC floor applies so
+ * a silent peer can never hold a session open forever. */
+int protocol_server_io_timeout_sec(int client_timeout);
 void* protocol_alloc(size_t size);
 void* protocol_realloc(void* ptr, size_t size);
 void protocol_session_set_8_bit_output(ProtocolSession* session, bool enabled);

tests/integration/common.py

@@ -254,6 +254,13 @@ def _wait_for_port(port, timeout=5):
 
 
 def _wait_proc(proc, timeout=5):
+    """Stop a long-lived subprocess promptly.  The server installs a SIGTERM
+    handler, so signal first and only escalate to SIGKILL if it does not exit;
+    waiting without signalling would burn the full timeout on every stop."""
+    if proc.poll() is not None:
+        proc.wait()
+        return
+    proc.terminate()
     try:
         proc.wait(timeout=timeout)
     except subprocess.TimeoutExpired:

tests/integration/test_features.py

@@ -1379,6 +1379,20 @@ class TestChecksumChoice:
                                    port=shared_server.port)
             assert result.returncode != 0, f"{bad} must be rejected"
 
+    @pytest.mark.ci
+    def test_compress_choice_auto_transfers(self, shared_server):
+        """--compress-choice=auto is normalized to zstd client-side, so the
+        receiver never rejects the transfer (#4)."""
+        clean_dir(DEST_DIR)
+        flags = ["-z", "--compress-choice=auto"]
+        result, _ = run_client(SOURCE_DIR, DEST_DIR, flags=flags, port=shared_server.port)
+        assert result.returncode == 0, \
+            f"--compress-choice=auto sync failed: {(result.stderr or result.stdout)[:300]}"
+        received = get_dest_received_dir(DEST_DIR, SOURCE_DIR)
+        mismatches, missing = verify_transfer(SOURCE_DIR, received)
+        assert not missing, f"Missing: {missing}"
+        assert not mismatches, f"Mismatch: {mismatches}"
+
     @pytest.mark.parametrize("algo", ["xxh64", "xxh3", "xxh128", "md5"])
     @pytest.mark.parametrize("mt", [False, True])
     def test_unchanged_skipped_and_bytes_preserved(self, shared_server, algo, mt):
@@ -2215,17 +2229,10 @@ class TestTempDir:
                                port=shared_server.port)
         assert result.returncode != 0, "a missing relative --temp-dir must fail"
 
-        missing_abs = os.path.join(TEST_DATA_DIR, "no_such_abs_scratch")
+    def test_temp_dir_absolute_rejected(self, shared_server):
-        assert not os.path.lexists(missing_abs)
+        """The receiver confines --temp-dir to the destination root: an absolute
-        clean_dir(dest)
+        (or `..`-escaping) value is rejected before any write, so a client can
-        result, _ = run_client(source, dest, flags=["--temp-dir", missing_abs],
+        never make the receiver create scratch files in an arbitrary directory."""
-                               port=shared_server.port)
-        assert result.returncode != 0, "a missing absolute --temp-dir must fail"
-
-    def test_temp_dir_absolute_outside_root_is_used(self, shared_server):
-        """rsync accepts any temp dir, including one outside the destination
-        tree; the completed files are still installed below the root and no
-        temp files remain in the scratch dir."""
         source = self._make_source("tempdir_abs_src")
         dest = os.path.join(TEST_DATA_DIR, "tempdir_abs_dst")
         clean_dir(dest)
@@ -2235,13 +2242,14 @@ class TestTempDir:
 
         result, _ = run_client(source, dest, flags=["--temp-dir", scratch],
                                port=shared_server.port)
-        assert result.returncode == 0, f"absolute temp-dir sync failed: {result.stderr[:200]}"
+        assert result.returncode != 0, "an absolute --temp-dir must be rejected"
-        received = get_dest_received_dir(dest, source)
+        assert os.listdir(scratch) == [], "receiver wrote into an unconfined temp dir"
-        mismatches, missing = verify_transfer(source, received)
+        # A relative traversal is rejected for the same reason.
-        assert not missing, f"Missing: {missing}"
+        result, _ = run_client(source, dest, flags=["--temp-dir=../escape_scratch"],
-        assert not mismatches, f"Mismatch: {mismatches}"
+                               port=shared_server.port)
-        self._assert_clean_scratch(scratch)
+        assert result.returncode != 0, "a `..` --temp-dir must be rejected"
         shutil.rmtree(scratch, ignore_errors=True)
+        shutil.rmtree(os.path.join(TEST_DATA_DIR, "escape_scratch"), ignore_errors=True)
 
 
 class TestTimeoutAndAllocLimits:
@@ -2285,7 +2293,8 @@ class TestTimeoutAndAllocLimits:
         assert not missing and not mismatches
 
     def test_temp_dir_cross_filesystem_fallback(self, shared_server):
-        """A --temp-dir on another filesystem must fall back to a non-atomic
+        """A confined relative --temp-dir that resolves (via a symlink under the
+        destination root) to another filesystem must fall back to a non-atomic
         copy instead of aborting (rsync parity).  Skipped when no second
         filesystem is available."""
         shm = "/dev/shm"
@@ -2298,14 +2307,18 @@ class TestTimeoutAndAllocLimits:
         os.makedirs(scratch)
         try:
             source, dest = self._seed("tempdir_xdev_src")
-            result, _ = run_client(source, dest, flags=["--temp-dir", scratch],
+            # The receiver resolves a relative temp dir under the destination
+            # root; a symlink there points the scratch at the second filesystem.
+            link = os.path.join(dest, "xdev_scratch")
+            os.symlink(scratch, link)
+            result, _ = run_client(source, dest, flags=["--temp-dir", "xdev_scratch"],
                                    port=shared_server.port)
             assert result.returncode == 0, f"cross-fs temp-dir failed: {result.stderr[:300]}"
             received = get_dest_received_dir(dest, source)
             mismatches, missing = verify_transfer(source, received)
             assert not missing, f"Missing: {missing}"
             assert not mismatches, f"Mismatch: {mismatches}"
-            assert os.listdir(scratch) == [], "temp files left behind"
+            assert os.listdir(scratch) == [], "temp files left behind in the cross-fs scratch"
         finally:
             shutil.rmtree(scratch, ignore_errors=True)
 
@@ -2910,6 +2923,43 @@ class TestRelativeFilesFrom:
             assert not os.path.exists(os.path.join(dest, "sub", "y.txt")), \
                 "directory-listed --delete did not remove the in-scope extra"
 
+    @pytest.mark.parametrize("mt", [False, True])
+    def test_relative_root_size_prune_protects_mirror_from_delete(self, mt):
+        """#12: a root-level --max-size prune under -R + --files-from must record
+        the bare relative wire path as its delete-protected prefix, so the
+        size-pruned entry's destination mirror survives --delete (rsync parity)."""
+        source = _make_relative_source("rel_rootsize_src")
+        # Big enough that a 100-byte cap prunes only this entry.
+        with open(os.path.join(source, "big.txt"), "wb") as fh:
+            fh.write(b"b" * 1000)
+        dest = os.path.join(TEST_DATA_DIR, "rel_rootsize_dst")
+        clean_dir(dest)
+        with ServerManager() as server:
+            server.start(extra_args=["--allow-delete"])
+            # "." lists the whole tree, so the receive root is a delete scope
+            # (a file-only list would leave the root out of scope, masking the
+            # protected-prefix mismatch this test targets).
+            lst = _write_rel_list(b".\n")
+            result, _ = run_client(source, dest,
+                                   flags=["--files-from", lst, "-R"] + (["--threads"] if mt else []),
+                                   port=server.port)
+            assert result.returncode == 0, f"seed -R sync failed: {result.stderr[:200]}"
+            assert os.path.isfile(os.path.join(dest, "big.txt"))
+            with open(os.path.join(dest, "unrelated.txt"), "w") as fh:
+                fh.write("x")
+
+            # --max-size=100 prunes only big.txt; its dest mirror is always protected.
+            result, _ = run_client(source, dest,
+                                   flags=["--files-from", lst, "-R", "--delete", "--max-size=100"] +
+                                         (["--threads"] if mt else []),
+                                   port=server.port)
+            assert result.returncode == 0, f"-R size+delete sync failed: {result.stderr[:300]}"
+            assert not os.path.exists(os.path.join(dest, "unrelated.txt")), "delete not active"
+            assert os.path.isfile(os.path.join(dest, "big.txt")), \
+                "the size-pruned entry's mirror was wrongly deleted (protected prefix mismatch)"
+            assert os.path.isfile(os.path.join(dest, "sub", "x.txt"))
+            assert os.path.isfile(os.path.join(dest, "top.txt"))
+
 
 class TestMissingArgs:
     """--ignore-missing-args / --delete-missing-args: a --files-from entry that

tests/test_client_cli.c

@@ -1518,6 +1518,9 @@ static void test_parse_args_compress_choice_parity() {
     int positional_args[2];
     int positional_count = 0;
     EXPECT_EQ_INT(parse_args(cfg, 5, argv, positional_args, &positional_count), 0);
+    /* "auto" is normalized to the canonical "zstd" the receiver accepts. */
+    EXPECT_EQ_STR(cfg->compress_choice, strcmp(good[i], "auto") == 0 ? "zstd" : good[i]);
+    EXPECT_EQ_INT(cfg->use_compression, strcmp(good[i], "none") != 0 ? 1 : 0);
     config_delete(cfg);
   }
   static const char* const bad[] = {"lz4", "zlib", "zlibx", "bogus"};
@@ -2326,6 +2329,8 @@ static void test_parse_args_log_file_format() {
   int positional_count = 0;
   EXPECT_EQ_INT(parse_args(cfg, 4, argv, positional_args, &positional_count), 0);
   EXPECT_EQ_STR(cfg->log_file_format, "%n %M");
+  /* The format alone is inert (no --log-file): no destination report needed. */
+  EXPECT_FALSE(cfg->report_dest_info);
   config_delete(cfg);
 
   cfg = config_create();
@@ -2334,6 +2339,61 @@ static void test_parse_args_log_file_format() {
   EXPECT_EQ_INT(parse_args(cfg, 5, separate_argv, positional_args, &positional_count), 0);
   EXPECT_EQ_STR(cfg->log_file_format, "%n %M");
   config_delete(cfg);
+
+  /* With --log-file the log-format is a real output mode whose %i/%n columns
+     need the receiver's destination snapshot (same as -i/--out-format). */
+  const char* log_path = "cli_log_fmt_test.txt";
+  cfg = config_create();
+  char log_arg[64];
+  snprintf(log_arg, sizeof(log_arg), "--log-file=%s", log_path);
+  char* both_argv[] = {"fastsync", log_arg, "--log-file-format=%i %n", "/src", "/dst"};
+  positional_count = 0;
+  EXPECT_EQ_INT(parse_args(cfg, 5, both_argv, positional_args, &positional_count), 0);
+  EXPECT_NOT_NULL(cfg->log_file);
+  EXPECT_TRUE(cfg->report_dest_info);
+  config_delete(cfg);
+  remove(log_path);
+}
+
+/* --skip-compress takes a separate value even when it starts with '-' (e.g. a
+ * suffix typed as "-foo"); the cluster expander must copy it verbatim rather
+ * than treat it as a short-option cluster. */
+static void test_parse_args_skip_compress_dash_value() {
+  Config* cfg = config_create();
+  char* argv[] = {"fastsync", "--skip-compress", "-foo/bar", "/src", "/dst"};
+  int positional_args[2];
+  int positional_count = 0;
+  EXPECT_EQ_INT(parse_args(cfg, 5, argv, positional_args, &positional_count), 0);
+  EXPECT_TRUE(cfg->skip_compress_set);
+  EXPECT_EQ_INT(cfg->skip_compress_count, 2);
+  EXPECT_EQ_STR(cfg->skip_compress_suffixes[0], "-foo");
+  EXPECT_EQ_STR(cfg->skip_compress_suffixes[1], "bar");
+  config_delete(cfg);
+}
+
+/* -i and --out-format also request the destination snapshot. */
+static void test_parse_args_report_dest_info_modes() {
+  Config* cfg = config_create();
+  char* itemize_argv[] = {"fastsync", "-i", "/src", "/dst"};
+  int positional_args[2];
+  int positional_count = 0;
+  EXPECT_EQ_INT(parse_args(cfg, 3, itemize_argv, positional_args, &positional_count), 0);
+  EXPECT_TRUE(cfg->report_dest_info);
+  config_delete(cfg);
+
+  cfg = config_create();
+  char* out_argv[] = {"fastsync", "--out-format=%n", "/src", "/dst"};
+  positional_count = 0;
+  EXPECT_EQ_INT(parse_args(cfg, 3, out_argv, positional_args, &positional_count), 0);
+  EXPECT_TRUE(cfg->report_dest_info);
+  config_delete(cfg);
+
+  cfg = config_create();
+  char* plain_argv[] = {"fastsync", "/src", "/dst"};
+  positional_count = 0;
+  EXPECT_EQ_INT(parse_args(cfg, 3, plain_argv, positional_args, &positional_count), 0);
+  EXPECT_FALSE(cfg->report_dest_info);
+  config_delete(cfg);
 }
 
 /* --delay-updates is a plain boolean receiver option. */
@@ -3344,6 +3404,24 @@ static void test_parse_args_remote_option_multiple() {
   config_delete(cfg);
 }
 
+/* The -M=value and -Mvalue short forms are expanded by the cluster expander to
+ * "-M value" before parsing; both must still collect the remote option (there
+ * is no dedicated -M= branch). */
+static void test_parse_args_remote_option_short_forms() {
+  static const char* const forms[] = {"-M=--allow-delete", "-M--allow-delete"};
+  for (size_t i = 0; i < sizeof(forms) / sizeof(forms[0]); i++) {
+    Config* cfg = valid_client_config();
+    EXPECT_NOT_NULL(cfg);
+    char* argv[] = {"fastsync", "--source-dir", "/src", "--dest-dir", "/dst", (char*)forms[i]};
+    int positional_args[2];
+    int positional_count = 0;
+    EXPECT_EQ_INT(parse_args(cfg, 6, argv, positional_args, &positional_count), 0);
+    EXPECT_EQ_INT(cfg->remote_option_count, 1);
+    EXPECT_EQ_STR(cfg->remote_options[0], "--allow-delete");
+    config_delete(cfg);
+  }
+}
+
 /* Space-separated form "--remote-option OPT" also parses. */
 static void test_parse_args_remote_option_space_form() {
   Config* cfg = valid_client_config();
@@ -4225,6 +4303,8 @@ void test_client_cli() {
   test_parse_args_list_only();
   test_parse_args_out_format();
   test_parse_args_log_file_format();
+  test_parse_args_report_dest_info_modes();
+  test_parse_args_skip_compress_dash_value();
   test_parse_args_checksum_choice_aliases();
   test_parse_args_checksum_choice_requires_value();
   test_parse_args_checksum_choice_equals_forms();
@@ -4253,6 +4333,7 @@ void test_client_cli() {
   test_parse_args_trust_sender_default_false();
   test_parse_args_trust_sender();
   test_parse_args_remote_option_multiple();
+  test_parse_args_remote_option_short_forms();
   test_parse_args_remote_option_space_form();
   test_parse_args_remote_option_missing_value();
   test_parse_args_remote_option_rejects_bad_values();

tests/test_config.c

@@ -552,6 +552,83 @@ static void test_config_send_receive() {
   }
 }
 
+/* #5: a received --max-alloc=0 (rsync's "no limit") is floored to the server
+ * ceiling on the receive path, so a client cannot disable it. */
+static void test_config_receive_max_alloc_zero_floored() {
+  Config* send_cfg = config_create();
+  EXPECT_NOT_NULL(send_cfg);
+  send_cfg->send_directory = str_dup("/send/src");
+  send_cfg->receive_root_directory = str_dup("/send/dst");
+  send_cfg->max_alloc = 0;
+
+  int p[2];
+  EXPECT_EQ_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, p), 0);
+  io_set_fds(p[0], p[1]);
+  io_set_bwlimit(0);
+
+  pid_t pid = fork();
+  if (pid == 0) {
+    close(p[1]);
+    io_set_fds(p[0], p[0]);
+    Config* recv_cfg = config_receive(p[0]);
+    bool ok = recv_cfg != NULL && recv_cfg->max_alloc == MAX_SERVER_ALLOC;
+    config_delete(recv_cfg);
+    close(p[0]);
+    close(p[1]);
+    _exit(ok ? 0 : 1);
+  } else {
+    close(p[0]);
+    io_set_fds(p[1], p[1]);
+    bool sent = config_send(p[1], send_cfg);
+    int status;
+    waitpid(pid, &status, 0);
+    close(p[0]);
+    close(p[1]);
+    config_delete(send_cfg);
+    EXPECT_TRUE(sent);
+    EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+  }
+}
+
+/* #4: a hostile/older client that still sends compress_choice=auto must be
+ * accepted (as zstd) rather than failing the whole transfer. */
+static void test_config_receive_compress_choice_auto_canonicalized() {
+  Config* send_cfg = config_create();
+  EXPECT_NOT_NULL(send_cfg);
+  send_cfg->send_directory = str_dup("/send/src");
+  send_cfg->receive_root_directory = str_dup("/send/dst");
+  free(send_cfg->compress_choice);
+  send_cfg->compress_choice = str_dup("auto");
+
+  int p[2];
+  EXPECT_EQ_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, p), 0);
+  io_set_fds(p[0], p[1]);
+  io_set_bwlimit(0);
+
+  pid_t pid = fork();
+  if (pid == 0) {
+    close(p[1]);
+    io_set_fds(p[0], p[0]);
+    Config* recv_cfg = config_receive(p[0]);
+    bool ok = recv_cfg != NULL && strcmp(recv_cfg->compress_choice, "zstd") == 0;
+    config_delete(recv_cfg);
+    close(p[0]);
+    close(p[1]);
+    _exit(ok ? 0 : 1);
+  } else {
+    close(p[0]);
+    io_set_fds(p[1], p[1]);
+    bool sent = config_send(p[1], send_cfg);
+    int status;
+    waitpid(pid, &status, 0);
+    close(p[0]);
+    close(p[1]);
+    config_delete(send_cfg);
+    EXPECT_TRUE(sent);
+    EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+  }
+}
+
 static void test_config_send_receive_version_mismatch() {
   /* A peer using the previous wire format must be rejected. */
   Config* cfg = config_create();
@@ -3051,6 +3128,8 @@ void test_config() {
   test_pipeline_receiver_lifecycle();
   if (!is_running_under_valgrind()) {
     test_config_send_receive();
+    test_config_receive_max_alloc_zero_floored();
+    test_config_receive_compress_choice_auto_canonicalized();
     test_config_local_only_fields_not_serialized();
     test_config_send_receive_version_mismatch();
     test_config_receive_truncated();

tests/test_file.c

@@ -28,6 +28,10 @@ static void test_file_create() {
   EXPECT_NULL(f->data->data);
   EXPECT_EQ_INT((int)f->data->size, 0);
   EXPECT_NULL(f->metadata);
+  /* An unset destination snapshot must read as known == false, never
+     indeterminate bytes (-i/--out-format without --incremental). */
+  EXPECT_FALSE(f->dest_state.known);
+  EXPECT_FALSE(f->dest_state.existed);
   file_destroy(f);
 }
 
@@ -326,6 +330,52 @@ static void test_file_save_to_disk_partial_install() {
   rmdir(root);
 }
 
+/* --temp-dir is a client-controlled wire value that must be confined below the
+ * receive root: an absolute or `..`-escaping value is rejected (a client must
+ * never make the receiver write scratch files in an arbitrary directory), while
+ * a relative one resolves under the root and is used for the atomic install. */
+static void test_file_save_to_disk_temp_dir_confined() {
+  const char* root = "test_temp_confine_tmp";
+  const char* dest_file = "test_temp_confine_tmp/file.txt";
+  char outside[PATH_MAX];
+  snprintf(outside, sizeof(outside), "/tmp/fastsync_temp_outside_%d", (int)getpid());
+  unlink(dest_file);
+  rmdir("test_temp_confine_tmp/scratch");
+  rmdir(root);
+  mkdir(root, 0755);
+  mkdir("test_temp_confine_tmp/scratch", 0755);
+  mkdir(outside, 0755);
+
+  File* f = file_create("file.txt");
+  EXPECT_NOT_NULL(f);
+  const char* content = "confined temp dir";
+  f->data->data = malloc(strlen(content));
+  EXPECT_NOT_NULL(f->data->data);
+  memcpy(f->data->data, content, strlen(content));
+  f->data->size = strlen(content);
+
+  Config* config = config_create();
+  EXPECT_NOT_NULL(config);
+  config->temp_dir = str_dup(outside);
+  EXPECT_EQ_INT(file_save_to_disk_full(root, f, config), FILE_SAVE_ERROR);
+  EXPECT_EQ_INT(access(dest_file, F_OK), -1);
+  free(config->temp_dir);
+  config->temp_dir = str_dup("../escape");
+  EXPECT_EQ_INT(file_save_to_disk_full(root, f, config), FILE_SAVE_ERROR);
+  EXPECT_EQ_INT(access(dest_file, F_OK), -1);
+  free(config->temp_dir);
+  config->temp_dir = str_dup("scratch");
+  EXPECT_EQ_INT(file_save_to_disk_full(root, f, config), FILE_SAVE_WRITTEN);
+  EXPECT_EQ_INT(access(dest_file, F_OK), 0);
+
+  file_destroy(f);
+  config_delete(config);
+  unlink(dest_file);
+  rmdir("test_temp_confine_tmp/scratch");
+  rmdir(root);
+  rmdir(outside);
+}
+
 /* Issue #251: file_save_to_disk_full must distinguish receiver-side skips
    (--existing/--ignore-existing/--update) from real writes so the sender can
    decide whether --remove-source-files may unlink its source. */
@@ -1883,6 +1933,81 @@ static void test_keep_dirlinks_secure_open() {
   file_set_keep_dirlinks(false);
 }
 
+/* Build an ArrayList of str_dup'd strings (NULL on allocation failure). */
+static ArrayList* make_manifest_string_list(const char* const* entries, int count) {
+  ArrayList* list = array_list_create(free);
+  if (!list)
+    return NULL;
+  for (int i = 0; i < count; i++) {
+    char* dup = str_dup(entries[i]);
+    if (!dup || !array_list_add(list, dup)) {
+      free(dup);
+      array_list_delete(list);
+      return NULL;
+    }
+  }
+  return list;
+}
+
+/* Regression (#3): a non-empty --delete-missing-args directory charges each
+ * removed entry exactly once.  The directory itself must not be counted twice;
+ * if it were, `deleted` would exceed --max-delete and the extras walk would
+ * underflow its remaining budget and delete past the user's cap. */
+static void test_manifest_delete_missing_dir_budget_double_count() {
+  char root[PATH_MAX];
+  snprintf(root, sizeof(root), "/tmp/fastsync_mgdir_%d", (int)getpid());
+  char* gone = path_cat(root, "gone");
+  char* gone_file = path_cat(gone, "f0");
+  char* extra = path_cat(root, "extra.txt");
+  EXPECT_NOT_NULL(gone);
+  EXPECT_NOT_NULL(gone_file);
+  EXPECT_NOT_NULL(extra);
+  mkdir(root, 0755);
+  mkdir(gone, 0755);
+  EXPECT_EQ_INT(access(extra, F_OK), -1);
+  EXPECT_TRUE(file_write_to_disk(extra, "extra", 5, false, false));
+  /* The missing-arg directory holds N-1 == 2 entries; with the directory itself
+     that is exactly --max-delete=3. */
+  EXPECT_TRUE(file_write_to_disk(gone_file, "x", 1, false, false));
+  char* gone_file2 = path_cat(gone, "f1");
+  EXPECT_TRUE(gone_file2 != NULL && file_write_to_disk(gone_file2, "x", 1, false, false));
+
+  Config* cfg = config_create();
+  EXPECT_NOT_NULL(cfg);
+  cfg->receive_root_directory = str_dup(root);
+  cfg->use_delete = true;
+  cfg->delete_missing_args = true;
+  cfg->max_delete = 3;
+
+  const char* missing_names[] = {"gone"};
+  const char* synced[] = {"."};
+  DeleteManifest manifest = {0};
+  manifest.keeps = make_manifest_string_list(NULL, 0);
+  manifest.missing = make_manifest_string_list(missing_names, 1);
+  manifest.dirs = make_manifest_string_list(synced, 1);
+  EXPECT_NOT_NULL(manifest.keeps);
+  EXPECT_NOT_NULL(manifest.missing);
+  EXPECT_NOT_NULL(manifest.dirs);
+
+  DeleteCommitResult result = manifest_delete_all(cfg, &manifest);
+  EXPECT_EQ_INT((int)result, (int)DELETE_COMMIT_LIMIT_REACHED);
+  /* The whole missing-arg directory is gone (dir + its 2 entries == 3). */
+  EXPECT_EQ_INT(access(gone, F_OK), -1);
+  /* The saturated budget must leave the in-scope extra untouched. */
+  EXPECT_EQ_INT(access(extra, F_OK), 0);
+
+  array_list_delete(manifest.keeps);
+  array_list_delete(manifest.missing);
+  array_list_delete(manifest.dirs);
+  config_delete(cfg);
+  unlink(extra);
+  free(gone);
+  free(gone_file);
+  free(gone_file2);
+  free(extra);
+  rmdir(root);
+}
+
 void test_file() {
   test_file_create();
   test_file_special_rdev_valid();
@@ -1896,6 +2021,7 @@ void test_file() {
   test_file_save_to_disk_ignore_existing();
   test_file_save_to_disk_ignore_existing_entry_types();
   test_file_save_to_disk_partial_install();
+  test_file_save_to_disk_temp_dir_confined();
   test_file_save_to_disk_reports_skips();
   test_file_write_to_disk_sparse_preserves_holes();
   test_file_write_to_disk_partial_retention();
@@ -1936,4 +2062,5 @@ void test_file() {
   test_inplace_overwrite_truncates_shorter_payload();
   test_inplace_refuses_fifo_destination();
   test_inplace_refuses_device_destination();
+  test_manifest_delete_missing_dir_budget_double_count();
 }

tests/test_protocol.c

@@ -522,10 +522,19 @@ static void test_data_create_starts_uncharged_and_unowned() {
   data_destroy(reserved);
 }
 
+/* The server floors a client --timeout=0 at SERVER_IO_TIMEOUT_SEC so a silent
+ * peer can never hold a session slot forever (slow-loris). */
+static void test_protocol_server_io_timeout_floor() {
+  EXPECT_EQ_INT(protocol_server_io_timeout_sec(0), SERVER_IO_TIMEOUT_SEC);
+  EXPECT_EQ_INT(protocol_server_io_timeout_sec(-7), SERVER_IO_TIMEOUT_SEC);
+  EXPECT_EQ_INT(protocol_server_io_timeout_sec(30), 30);
+  EXPECT_TRUE(SERVER_IO_TIMEOUT_SEC > 0);
+}
+
 static void test_protocol_session_io_timeout() {
-  /* Default is the built-in 60 s window; the setter stores exactly what it is
+  /* The default is the built-in 60 s window; the setter stores exactly what it
-   * given (<= 0 means "fall back to the default") so callers can propagate
+   * is given (<= 0 disables the deadline, matching rsync's --timeout=0) so
-   * --timeout without special-casing 0. */
+   * callers can propagate --timeout without special-casing 0. */
   ProtocolSession session;
   protocol_session_init(&session, -1, -1);
   EXPECT_EQ_INT(session.io_timeout_sec, 60);
@@ -670,6 +679,7 @@ void test_protocol() {
   test_send_receive_int();
   test_send_receive_status();
   test_protocol_session_io_timeout();
+  test_protocol_server_io_timeout_floor();
   test_send_receive_status_timed();
   test_receive_status_keepalive_skips_reply();
   test_receive_status_keepalive_aborts();