Merge remote-tracking branch 'origin/feat/existing' into dev

src/shared/config.c

@@ -74,6 +74,7 @@ static void config_set_defaults(Config* config) {
   config->list_only = false;
   config->human_readable = false;
   config->eight_bit_output = false;
+  config->existing = false;
   config->update = false;
   config->inplace = false;
   config->use_fsync = false;
@@ -130,9 +131,10 @@ static bool validate_received_config(const Config* config) {
          valid_wire_bool(config->safe_links) && valid_wire_bool(config->copy_unsafe_links) &&
          valid_wire_bool(config->preserve_hard_links) && valid_wire_bool(config->preserve_acls) &&
          valid_wire_bool(config->preserve_xattrs) && valid_wire_bool(config->preserve_devices) &&
-         valid_wire_bool(config->preserve_sparse) && valid_wire_bool(config->update) &&
-         valid_wire_bool(config->inplace) && valid_wire_bool(config->append) &&
-         valid_wire_bool(config->use_fsync) && valid_wire_bool(config->append_verify) &&
+         valid_wire_bool(config->preserve_sparse) && valid_wire_bool(config->existing) &&
+         valid_wire_bool(config->update) && valid_wire_bool(config->inplace) &&
+         valid_wire_bool(config->append) && valid_wire_bool(config->use_fsync) &&
+         valid_wire_bool(config->append_verify) &&
          valid_wire_bool(config->delete_excluded) && valid_wire_bool(config->delete_after) &&
          valid_wire_bool(config->relative) && valid_wire_bool(config->prune_empty_dirs) &&
          valid_wire_bool(config->partial) && valid_wire_bool(config->delete_before) &&
@@ -255,8 +257,9 @@ static bool send_file_options(int fd, const Config* c) {
 }
 
 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->use_fsync) && send_int(fd, c->append_verify) &&
+  return send_int(fd, c->existing) && send_int(fd, c->update) && send_int(fd, c->inplace) &&
+         send_int(fd, c->append) && send_int(fd, c->use_fsync) &&
+         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);
@@ -325,7 +328,8 @@ static bool receive_file_options(int fd, Config* c) {
 }
 
 static bool receive_selection_options(int fd, Config* c) {
-  bool* flags[] = {&c->update,        &c->inplace,         &c->append,      &c->use_fsync,
+  bool* flags[] = {&c->existing,      &c->update,          &c->inplace,     &c->append,
+                   &c->use_fsync,
                    &c->append_verify, &c->delete_excluded, &c->delete_after};
   for (size_t i = 0; i < sizeof(flags) / sizeof(flags[0]); i++) {
     if (!receive_wire_bool(fd, flags[i]))

src/shared/config.h

@@ -82,6 +82,7 @@ typedef struct Config {
   bool eight_bit_output;
 
   // Issue #127: Transfer modes
+  bool existing;
   bool update;
   bool inplace;
   bool use_fsync;

src/shared/file_receive.c

@@ -29,6 +29,7 @@ bool file_save_to_disk(const char* root_directory, const File* file, const Confi
   const char* backup_dir = (config && config->backup_dir) ? config->backup_dir : NULL;
   const char* partial_dir = (config && config->partial_dir) ? config->partial_dir : NULL;
   char *confined_backup = NULL, *confined_partial = NULL, *disk_path = NULL;
+  char* destination_path = NULL;
   char *backup_path = NULL, *parent_copy = NULL;
 
   if (!file || !file->path || !file->data || (file->data->size != 0 && !file->data->data) ||
@@ -54,13 +55,27 @@ bool file_save_to_disk(const char* root_directory, const File* file, const Confi
 
   const char* actual_root =
       (partial_dir && config && config->partial) ? confined_partial : root_directory;
+  destination_path = path_cat(root_directory, file->path);
   disk_path = path_cat(actual_root, file->path);
-  if (disk_path == NULL) {
+  if (destination_path == NULL || disk_path == NULL) {
     free(confined_backup);
     free(confined_partial);
+    free(destination_path);
+    free(disk_path);
     return false;
   }
 
+  /* --existing checks the final destination, not a temporary partial path. */
+  if (config && config->existing && !file_path_exists_secure(destination_path)) {
+    free(confined_backup);
+    free(confined_partial);
+    free(destination_path);
+    free(disk_path);
+    return true;
+  }
+  free(destination_path);
+  destination_path = NULL;
+
   /* --update is receiver-side policy: never replace a newer destination.
      The secure stat does not require read permission on the destination. */
   if (config && config->update && file_destination_is_newer_secure(disk_path, file->metadata)) {
@@ -110,6 +125,7 @@ bool file_save_to_disk(const char* root_directory, const File* file, const Confi
   free(backup_path);
   free(confined_backup);
   free(confined_partial);
+  free(destination_path);
   free(disk_path);
   return ok;
 
@@ -118,6 +134,7 @@ fail:
   free(backup_path);
   free(confined_backup);
   free(confined_partial);
+  free(destination_path);
   free(disk_path);
   return false;
 }