Пример #1
0
/**
 * glnx_dirfd_iterator_next_dent_ensure_dtype:
 * @dfd_iter: A directory iterator
 * @out_dent: (out) (transfer none): Pointer to dirent; do not free
 * @cancellable: Cancellable
 * @error: Error
 *
 * A variant of @glnx_dirfd_iterator_next_dent, which will ensure the
 * `dent->d_type` member is filled in by calling `fstatat`
 * automatically if the underlying filesystem type sets `DT_UNKNOWN`.
 */
gboolean
glnx_dirfd_iterator_next_dent_ensure_dtype (GLnxDirFdIterator  *dfd_iter,
                                            struct dirent     **out_dent,
                                            GCancellable       *cancellable,
                                            GError            **error)
{
  gboolean ret = FALSE;
  struct dirent *ret_dent;

  g_return_val_if_fail (out_dent, FALSE);

  if (!glnx_dirfd_iterator_next_dent (dfd_iter, out_dent, cancellable, error))
    goto out;

  ret_dent = *out_dent;

  if (ret_dent)
    {

      if (ret_dent->d_type == DT_UNKNOWN)
        {
          struct stat stbuf;
          if (TEMP_FAILURE_RETRY (fstatat (dfd_iter->fd, ret_dent->d_name, &stbuf, AT_SYMLINK_NOFOLLOW)) != 0)
            {
              glnx_set_error_from_errno (error);
              goto out;
            }
          ret_dent->d_type = IFTODT (stbuf.st_mode);
        }
    }

  ret = TRUE;
 out:
  return ret;
}
Пример #2
0
static gboolean
do_read_run (GLnxDirFdIterator *dfd_iter,
             guint *out_n_read,
             GError **error)
{
  guint nattrs = 0;
  while (TRUE)
    {
      struct dirent *dent;
      if (!glnx_dirfd_iterator_next_dent (dfd_iter, &dent, NULL, error))
        return FALSE;
      if (!dent)
        break;

      glnx_autofd int fd = -1;
      if (!glnx_openat_rdonly (dfd_iter->fd, dent->d_name, FALSE, &fd, error))
        return FALSE;

      g_autoptr(GVariant) current_xattrs = NULL;
      if (!glnx_fd_get_all_xattrs (fd, &current_xattrs, NULL, error))
        return FALSE;

      /* We don't actually care about the values, just use the variable
       * to avoid compiler warnings.
       */
      nattrs += g_variant_n_children (current_xattrs);
    }

  *out_n_read = nattrs;
  return TRUE;
}
Пример #3
0
/**
 * ostree_repo_checkout_gc:
 * @self: Repo
 * @cancellable: Cancellable
 * @error: Error
 *
 * Call this after finishing a succession of checkout operations; it
 * will delete any currently-unused uncompressed objects from the
 * cache.
 */
gboolean
ostree_repo_checkout_gc (OstreeRepo        *self,
                         GCancellable      *cancellable,
                         GError           **error)
{
  gboolean ret = FALSE;
  g_autoptr(GHashTable) to_clean_dirs = NULL;
  GHashTableIter iter;
  gpointer key, value;

  g_mutex_lock (&self->cache_lock);
  to_clean_dirs = self->updated_uncompressed_dirs;
  self->updated_uncompressed_dirs = g_hash_table_new (NULL, NULL);
  g_mutex_unlock (&self->cache_lock);

  if (to_clean_dirs)
    g_hash_table_iter_init (&iter, to_clean_dirs);
  while (to_clean_dirs && g_hash_table_iter_next (&iter, &key, &value))
    {
      g_autofree char *objdir_name = g_strdup_printf ("%02x", GPOINTER_TO_UINT (key));
      g_auto(GLnxDirFdIterator) dfd_iter = { 0, };

      if (!glnx_dirfd_iterator_init_at (self->uncompressed_objects_dir_fd, objdir_name, FALSE,
                                        &dfd_iter, error))
        goto out;

      while (TRUE)
        {
          struct dirent *dent;
          struct stat stbuf;

          if (!glnx_dirfd_iterator_next_dent (&dfd_iter, &dent, cancellable, error))
            goto out;
          if (dent == NULL)
            break;

          if (fstatat (dfd_iter.fd, dent->d_name, &stbuf, AT_SYMLINK_NOFOLLOW) != 0)
            {
              glnx_set_error_from_errno (error);
              goto out;
            }
          
          if (stbuf.st_nlink == 1)
            {
              if (unlinkat (dfd_iter.fd, dent->d_name, 0) != 0)
                {
                  glnx_set_error_from_errno (error);
                  goto out;
                }
            }
        }
    }

  ret = TRUE;
 out:
  return ret;
}
Пример #4
0
static gboolean
_ostree_repo_prune_tmp (OstreeRepo *self,
                        GCancellable *cancellable,
                        GError **error)
{
  if (self->cache_dir_fd == -1)
    return TRUE;

  g_auto(GLnxDirFdIterator) dfd_iter = { 0, };
  gboolean exists;
  if (!ot_dfd_iter_init_allow_noent (self->cache_dir_fd, _OSTREE_SUMMARY_CACHE_DIR,
                                     &dfd_iter, &exists, error))
    return FALSE;
  /* Note early return */
  if (!exists)
    return TRUE;

  while (TRUE)
    {
      size_t len;
      gboolean has_sig_suffix = FALSE;
      struct dirent *dent;
      g_autofree gchar *d_name = NULL;

      if (!glnx_dirfd_iterator_next_dent (&dfd_iter, &dent, cancellable, error))
        return FALSE;
      if (dent == NULL)
        break;

      /* dirent->d_name can't be modified directly; see `man 3 readdir` */
      d_name = g_strdup (dent->d_name);
      len = strlen (d_name);
      if (len > 4 && g_strcmp0 (d_name + len - 4, ".sig") == 0)
        {
          has_sig_suffix = TRUE;
          d_name[len - 4] = '\0';
        }

      if (!g_hash_table_contains (self->remotes, d_name))
        {
          /* Restore the previous value to get the file name.  */
          if (has_sig_suffix)
            d_name[len - 4] = '.';

          if (!glnx_unlinkat (dfd_iter.fd, d_name, 0, error))
            return FALSE;
        }
    }

  return TRUE;
}
Пример #5
0
static GString *
get_directory_listing (int dfd,
                       const char *path)
{
  g_autoptr(GPtrArray) entries = g_ptr_array_new_with_free_func (g_free);
  g_auto(GLnxDirFdIterator) dfd_iter = { 0, };
  g_autoptr(GError) local_error = NULL;
  GError **error = &local_error;
  guint i;
  char *escaped;
  GString *listing;

  listing = g_string_new ("<html>\r\n");

  if (!glnx_dirfd_iterator_init_at (dfd, path, FALSE, &dfd_iter, error))
    goto out;

  while (TRUE)
    {
      struct dirent *dent;

      if (!glnx_dirfd_iterator_next_dent (&dfd_iter, &dent, NULL, error))
        goto out;

      if (dent == NULL)
        break;

      escaped = g_markup_escape_text (dent->d_name, -1);
      g_ptr_array_add (entries, escaped);
    }

  g_ptr_array_sort (entries, (GCompareFunc)compare_strings);

  escaped = g_markup_escape_text (strchr (path, '/'), -1);
  g_string_append_printf (listing, "<head><title>Index of %s</title></head>\r\n", escaped);
  g_string_append_printf (listing, "<body><h1>Index of %s</h1>\r\n<p>\r\n", escaped);
  g_free (escaped);
  for (i = 0; i < entries->len; i++)
    {
      g_string_append_printf (listing, "<a href=\"%s\">%s</a><br>\r\n",
                              (char *)entries->pdata[i], 
                              (char *)entries->pdata[i]);
      g_free (g_steal_pointer (&entries->pdata[i]));
    }
  g_string_append (listing, "</body>\r\n</html>\r\n");
 out:
  if (local_error)
    g_printerr ("%s\n", local_error->message);
  return listing;
}
Пример #6
0
static gboolean
do_write_run (GLnxDirFdIterator *dfd_iter, GError **error)
{
  WriteType wtype = g_random_int () % 2;

  if (wtype == WRITE_RUN_CREATE)
    {
      guint32 randname_v = g_random_int ();
      g_autofree char *randname = g_strdup_printf ("file%u", randname_v);
      glnx_autofd int fd = -1;

    again:
      fd = openat (dfd_iter->fd, randname, O_CREAT | O_EXCL, 0644);
      if (fd < 0)
        {
          if (errno == EEXIST)
            {
              g_printerr ("Congratulations!  I suggest purchasing a lottery ticket today!\n");
              goto again;
            }
          else
            {
              glnx_set_error_from_errno (error);
              return FALSE;
            }
        }

      if (!add_random_xattrs (fd, error))
        return FALSE;
      }
  else if (wtype == WRITE_RUN_MUTATE)
    {
      while (TRUE)
        {
          struct dirent *dent;
          if (!glnx_dirfd_iterator_next_dent (dfd_iter, &dent, NULL, error))
            return FALSE;
          if (!dent)
            break;

          glnx_autofd int fd = -1;
          if (!glnx_openat_rdonly (dfd_iter->fd, dent->d_name, FALSE, &fd, error))
            return FALSE;

          g_autoptr(GVariant) current_xattrs = NULL;
          if (!glnx_fd_get_all_xattrs (fd, &current_xattrs, NULL, error))
            return FALSE;

          for (int i = 0; i < g_variant_n_children (current_xattrs); i++)
            {
              const char *name, *value;
              g_variant_get_child (current_xattrs, i, "(^&ay^&ay)", &name, &value);

              /* We don't want to potentially test/change xattrs like security.selinux
               * that were injected by the system.
               */
              if (!g_str_has_prefix (name, "user.test"))
                continue;

              if (!set_random_xattr_value (fd, name, error))
                return FALSE;
            }
        }
    }
  else
    g_assert_not_reached ();

  return TRUE;
}
static gboolean
export_dir (int           source_parent_fd,
            const char   *source_name,
            const char   *source_relpath,
            int           destination_parent_fd,
            const char   *destination_name,
            const char   *required_prefix,
            GCancellable *cancellable,
            GError      **error)
{
  int res;

  g_auto(GLnxDirFdIterator) source_iter = {0};
  glnx_fd_close int destination_dfd = -1;
  struct dirent *dent;

  if (!glnx_dirfd_iterator_init_at (source_parent_fd, source_name, FALSE, &source_iter, error))
    return FALSE;

  do
    res = mkdirat (destination_parent_fd, destination_name, 0755);
  while (G_UNLIKELY (res == -1 && errno == EINTR));
  if (res == -1)
    {
      if (errno != EEXIST)
        {
          glnx_set_error_from_errno (error);
          return FALSE;
        }
    }

  if (!glnx_opendirat (destination_parent_fd, destination_name, TRUE,
                       &destination_dfd, error))
    return FALSE;

  while (TRUE)
    {
      struct stat stbuf;
      g_autofree char *source_printable = NULL;

      if (!glnx_dirfd_iterator_next_dent (&source_iter, &dent, cancellable, error))
        return FALSE;

      if (dent == NULL)
        break;

      if (fstatat (source_iter.fd, dent->d_name, &stbuf, AT_SYMLINK_NOFOLLOW) == -1)
        {
          if (errno == ENOENT)
            {
              continue;
            }
          else
            {
              glnx_set_error_from_errno (error);
              return FALSE;
            }
        }

      /* Don't export any hidden files or backups */
      if (g_str_has_prefix (dent->d_name, ".") ||
          g_str_has_suffix (dent->d_name, "~"))
        continue;

      if (S_ISDIR (stbuf.st_mode))
        {
          g_autofree gchar *child_relpath = g_build_filename (source_relpath, dent->d_name, NULL);

          if (!export_dir (source_iter.fd, dent->d_name, child_relpath, destination_dfd, dent->d_name,
                           required_prefix, cancellable, error))
            return FALSE;
        }
      else if (S_ISREG (stbuf.st_mode))
        {
          source_printable = g_build_filename (source_relpath, dent->d_name, NULL);


          if (!flatpak_has_name_prefix (dent->d_name, required_prefix))
            {
              g_print ("Not exporting %s, wrong prefix\n", source_printable);
              continue;
            }

          g_print ("Exporting %s\n", source_printable);

          if (!glnx_file_copy_at (source_iter.fd, dent->d_name, &stbuf,
                                  destination_dfd, dent->d_name,
                                  GLNX_FILE_COPY_NOXATTRS,
                                  cancellable,
                                  error))
            return FALSE;
        }
      else
        {
          source_printable = g_build_filename (source_relpath, dent->d_name, NULL);
          g_debug ("Not exporting non-regular file %s\n", source_printable);
        }
    }

  /* Try to remove the directory, as we don't want to export empty directories.
   * However, don't fail if the unlink fails due to the directory not being empty */
  do
    res = unlinkat (destination_parent_fd, destination_name, AT_REMOVEDIR);
  while (G_UNLIKELY (res == -1 && errno == EINTR));
  if (res == -1)
    {
      if (errno != ENOTEMPTY)
        {
          glnx_set_error_from_errno (error);
          return FALSE;
        }
    }

  return TRUE;
}
Пример #8
0
gboolean
_ostree_sysroot_read_boot_loader_configs (OstreeSysroot *self,
                                          int            bootversion,
                                          GPtrArray    **out_loader_configs,
                                          GCancellable  *cancellable,
                                          GError       **error)
{
  gboolean ret = FALSE;
  int fd; /* Temporary owned by iterator */
  g_autofree char *entries_path = g_strdup_printf ("boot/loader.%d/entries", bootversion);
  g_autoptr(GPtrArray) ret_loader_configs = NULL;
  g_auto(GLnxDirFdIterator) dfd_iter = { 0, };

  if (!ensure_sysroot_fd (self, error))
    goto out;

  ret_loader_configs = g_ptr_array_new_with_free_func ((GDestroyNotify)g_object_unref);

  fd = glnx_opendirat_with_errno (self->sysroot_fd, entries_path, TRUE);
  if (fd == -1)
    {
      if (errno == ENOENT)
        goto done;
      else
        {
          glnx_set_error_from_errno (error);
          goto out;
        }
    }

  if (!glnx_dirfd_iterator_init_take_fd (fd, &dfd_iter, error))
    goto out;

  while (TRUE)
    {
      struct dirent *dent;
      struct stat stbuf;

      if (!glnx_dirfd_iterator_next_dent (&dfd_iter, &dent, cancellable, error))
        goto out;
          
      if (dent == NULL)
        break;

      if (fstatat (dfd_iter.fd, dent->d_name, &stbuf, 0) != 0)
        {
          glnx_set_error_from_errno (error);
          goto out;
        }

      if (g_str_has_prefix (dent->d_name, "ostree-") &&
          g_str_has_suffix (dent->d_name, ".conf") &&
          S_ISREG (stbuf.st_mode))
        {
          glnx_unref_object OstreeBootconfigParser *config = ostree_bootconfig_parser_new ();
  
          if (!ostree_bootconfig_parser_parse_at (config, dfd_iter.fd, dent->d_name, cancellable, error))
            {
              g_prefix_error (error, "Parsing %s: ", dent->d_name);
              goto out;
            }

          g_ptr_array_add (ret_loader_configs, g_object_ref (config));
        }
    }

 done:
  gs_transfer_out_value (out_loader_configs, &ret_loader_configs);
  ret = TRUE;
 out:
  return ret;
}
static gboolean
export_dir (int            source_parent_fd,
            const char    *source_name,
            const char    *source_relpath,
            int            destination_parent_fd,
            const char    *destination_name,
            const char    *required_prefix,
            GCancellable  *cancellable,
            GError       **error)
{
  gboolean ret = FALSE;
  int res;
  g_auto(GLnxDirFdIterator) source_iter = {0};
  glnx_fd_close int destination_dfd = -1;
  struct dirent *dent;

  if (!glnx_dirfd_iterator_init_at (source_parent_fd, source_name, FALSE, &source_iter, error))
    goto out;

  do
    res = mkdirat (destination_parent_fd, destination_name, 0777);
  while (G_UNLIKELY (res == -1 && errno == EINTR));
  if (res == -1)
    {
      if (errno != EEXIST)
        {
          glnx_set_error_from_errno (error);
          goto out;
        }
    }

  if (!gs_file_open_dir_fd_at (destination_parent_fd, destination_name,
                               &destination_dfd,
                               cancellable, error))
    goto out;

  while (TRUE)
    {
      struct stat stbuf;
      g_autofree char *source_printable = NULL;

      if (!glnx_dirfd_iterator_next_dent (&source_iter, &dent, cancellable, error))
        goto out;

      if (dent == NULL)
        break;

      if (fstatat (source_iter.fd, dent->d_name, &stbuf, AT_SYMLINK_NOFOLLOW) == -1)
        {
          if (errno == ENOENT)
            continue;
          else
            {
              glnx_set_error_from_errno (error);
              goto out;
            }
        }

      if (S_ISDIR (stbuf.st_mode))
        {
          g_autofree gchar *child_relpath = g_build_filename(source_relpath, dent->d_name, NULL);

          if (!export_dir (source_iter.fd, dent->d_name, child_relpath, destination_dfd, dent->d_name,
                           required_prefix, cancellable, error))
            goto out;
        }
      else if (S_ISREG (stbuf.st_mode))
        {
          source_printable = g_build_filename (source_relpath, dent->d_name, NULL);


          if (!xdg_app_has_name_prefix (dent->d_name, required_prefix))
            {
              g_print ("Not exporting %s, wrong prefix\n", source_printable);
              continue;
            }

          g_print ("Exporting %s\n", source_printable);

          if (!glnx_file_copy_at (source_iter.fd, dent->d_name, &stbuf,
                                  destination_dfd, dent->d_name,
                                  GLNX_FILE_COPY_NOXATTRS,
                                  cancellable,
                                  error))
            goto out;
        }
      else
        {
          source_printable = g_build_filename (source_relpath, dent->d_name, NULL);
          g_print ("Not exporting non-regular file %s\n", source_printable);
        }
    }

  ret = TRUE;
 out:

  return ret;
}
Пример #10
0
/* TODO: Add a man page. */
gboolean
ostree_builtin_create_usb (int            argc,
                           char         **argv,
                           OstreeCommandInvocation *invocation,
                           GCancellable  *cancellable,
                           GError       **error)
{
  g_autoptr(GOptionContext) context = NULL;
  g_autoptr(OstreeAsyncProgress) progress = NULL;
  g_auto(GLnxConsoleRef) console = { 0, };

  context = g_option_context_new ("MOUNT-PATH COLLECTION-ID REF [COLLECTION-ID REF...]");

  /* Parse options. */
  g_autoptr(OstreeRepo) src_repo = NULL;

  if (!ostree_option_context_parse (context, options, &argc, &argv, invocation, &src_repo, cancellable, error))
    return FALSE;

  if (argc < 2)
    {
      ot_util_usage_error (context, "A MOUNT-PATH must be specified", error);
      return FALSE;
    }

  if (argc < 4)
    {
      ot_util_usage_error (context, "At least one COLLECTION-ID REF pair must be specified", error);
      return FALSE;
    }

  if (argc % 2 == 1)
    {
      ot_util_usage_error (context, "Only complete COLLECTION-ID REF pairs may be specified", error);
      return FALSE;
    }

  /* Open the USB stick, which must exist. Allow automounting and following symlinks. */
  const char *mount_root_path = argv[1];
  struct stat mount_root_stbuf;

  glnx_autofd int mount_root_dfd = -1;
  if (!glnx_opendirat (AT_FDCWD, mount_root_path, TRUE, &mount_root_dfd, error))
    return FALSE;
  if (!glnx_fstat (mount_root_dfd, &mount_root_stbuf, error))
    return FALSE;

  /* Read in the refs to add to the USB stick. */
  g_autoptr(GPtrArray) refs = g_ptr_array_new_full (argc, (GDestroyNotify) ostree_collection_ref_free);

  for (gsize i = 2; i < argc; i += 2)
    {
      if (!ostree_validate_collection_id (argv[i], error) ||
          !ostree_validate_rev (argv[i + 1], error))
        return FALSE;

      g_ptr_array_add (refs, ostree_collection_ref_new (argv[i], argv[i + 1]));
    }

  /* Open the destination repository on the USB stick or create it if it doesn’t exist.
   * Check it’s below @mount_root_path, and that it’s not the same as the source
   * repository.
   *
   * If the destination file system supports xattrs (for example, ext4), we use
   * a BARE_USER repository; if it doesn’t (for example, FAT), we use ARCHIVE.
   * In either case, we want a lossless repository. */
  const char *dest_repo_path = (opt_destination_repo != NULL) ? opt_destination_repo : ".ostree/repo";

  if (!glnx_shutil_mkdir_p_at (mount_root_dfd, dest_repo_path, 0755, cancellable, error))
    return FALSE;

  OstreeRepoMode mode = OSTREE_REPO_MODE_BARE_USER;

  if (TEMP_FAILURE_RETRY (fgetxattr (mount_root_dfd, "user.test", NULL, 0)) < 0 &&
      (errno == ENOTSUP || errno == EOPNOTSUPP))
    mode = OSTREE_REPO_MODE_ARCHIVE;

  g_debug ("%s: Creating repository in mode %u", G_STRFUNC, mode);

  g_autoptr(OstreeRepo) dest_repo = ostree_repo_create_at (mount_root_dfd, dest_repo_path,
                                                           mode, NULL, cancellable, error);

  if (dest_repo == NULL)
    return FALSE;

  struct stat dest_repo_stbuf;

  if (!glnx_fstat (ostree_repo_get_dfd (dest_repo), &dest_repo_stbuf, error))
    return FALSE;

  if (dest_repo_stbuf.st_dev != mount_root_stbuf.st_dev)
    {
      ot_util_usage_error (context, "--destination-repo must be a descendent of MOUNT-PATH", error);
      return FALSE;
    }

  if (ostree_repo_equal (src_repo, dest_repo))
    {
      ot_util_usage_error (context, "--destination-repo must not be the source repository", error);
      return FALSE;
    }

  if (!ostree_ensure_repo_writable (dest_repo, error))
    return FALSE;

  if (opt_disable_fsync)
    ostree_repo_set_disable_fsync (dest_repo, TRUE);

  /* Copy across all of the collection–refs to the destination repo. */
  GVariantBuilder refs_builder;
  g_variant_builder_init (&refs_builder, G_VARIANT_TYPE ("a(sss)"));

  for (gsize i = 0; i < refs->len; i++)
    {
      const OstreeCollectionRef *ref = g_ptr_array_index (refs, i);

      g_variant_builder_add (&refs_builder, "(sss)",
                             ref->collection_id, ref->ref_name, "");
    }

  {
    GVariantBuilder builder;
    g_autoptr(GVariant) opts = NULL;
    OstreeRepoPullFlags flags = OSTREE_REPO_PULL_FLAGS_MIRROR;

    glnx_console_lock (&console);

    if (console.is_tty)
      progress = ostree_async_progress_new_and_connect (ostree_repo_pull_default_console_progress_changed, &console);

    g_variant_builder_init (&builder, G_VARIANT_TYPE ("a{sv}"));

    g_variant_builder_add (&builder, "{s@v}", "collection-refs",
                           g_variant_new_variant (g_variant_builder_end (&refs_builder)));
    g_variant_builder_add (&builder, "{s@v}", "flags",
                           g_variant_new_variant (g_variant_new_int32 (flags)));
    g_variant_builder_add (&builder, "{s@v}", "depth",
                           g_variant_new_variant (g_variant_new_int32 (0)));
    opts = g_variant_ref_sink (g_variant_builder_end (&builder));

    g_autofree char *src_repo_uri = g_file_get_uri (ostree_repo_get_path (src_repo));

    if (!ostree_repo_pull_with_options (dest_repo, src_repo_uri,
                                        opts,
                                        progress,
                                        cancellable, error))
      {
        ostree_repo_abort_transaction (dest_repo, cancellable, NULL);
        return FALSE;
      }

    if (progress != NULL)
      ostree_async_progress_finish (progress);
  }

  /* Ensure a summary file is present to make it easier to look up commit checksums. */
  /* FIXME: It should be possible to work without this, but find_remotes_cb() in
   * ostree-repo-pull.c currently assumes a summary file (signed or unsigned) is
   * present. */
  struct stat stbuf;
  if (!glnx_fstatat_allow_noent (ostree_repo_get_dfd (dest_repo), "summary", &stbuf, 0, error))
    return FALSE;
  if (errno == ENOENT &&
      !ostree_repo_regenerate_summary (dest_repo, NULL, cancellable, error))
    return FALSE;

  /* Add the symlinks .ostree/repos.d/@symlink_name → @dest_repo_path, unless
   * the @dest_repo_path is a well-known one like ostree/repo, in which case no
   * symlink is necessary; #OstreeRepoFinderMount always looks there. */
  if (!g_str_equal (dest_repo_path, "ostree/repo") &&
      !g_str_equal (dest_repo_path, ".ostree/repo"))
    {
      if (!glnx_shutil_mkdir_p_at (mount_root_dfd, ".ostree/repos.d", 0755, cancellable, error))
        return FALSE;

      /* Find a unique name for the symlink. If a symlink already targets
       * @dest_repo_path, use that and don’t create a new one. */
      GLnxDirFdIterator repos_iter;
      gboolean need_symlink = TRUE;

      if (!glnx_dirfd_iterator_init_at (mount_root_dfd, ".ostree/repos.d", TRUE, &repos_iter, error))
        return FALSE;

      while (TRUE)
        {
          struct dirent *repo_dent;

          if (!glnx_dirfd_iterator_next_dent (&repos_iter, &repo_dent, cancellable, error))
            return FALSE;

          if (repo_dent == NULL)
            break;

          /* Does the symlink already point to this repository? (Or is the
           * repository itself present in repos.d?) We already guarantee that
           * they’re on the same device. */
          if (repo_dent->d_ino == dest_repo_stbuf.st_ino)
            {
              need_symlink = FALSE;
              break;
            }
        }

      /* If we need a symlink, find a unique name for it and create it. */
      if (need_symlink)
        {
          /* Relative to .ostree/repos.d. */
          g_autofree char *relative_dest_repo_path = g_build_filename ("..", "..", dest_repo_path, NULL);
          guint i;
          const guint max_attempts = 100;

          for (i = 0; i < max_attempts; i++)
            {
              g_autofree char *symlink_path = g_strdup_printf (".ostree/repos.d/%02u-generated", i);

              int ret = TEMP_FAILURE_RETRY (symlinkat (relative_dest_repo_path, mount_root_dfd, symlink_path));
              if (ret < 0 && errno != EEXIST)
                return glnx_throw_errno_prefix (error, "symlinkat(%s → %s)", symlink_path, relative_dest_repo_path);
              else if (ret >= 0)
                break;
            }

          if (i == max_attempts)
            return glnx_throw (error, "Could not find an unused symlink name for the repository");
        }
    }

  /* Report success to the user. */
  g_autofree char *src_repo_path = g_file_get_path (ostree_repo_get_path (src_repo));

  g_print ("Copied %u/%u refs successfully from ‘%s’ to ‘%s’ repository in ‘%s’.\n", refs->len, refs->len,
           src_repo_path, dest_repo_path, mount_root_path);

  return TRUE;
}