extensions: Support merge-dirs=list..

This causes the listed directories to become symlink farms
into all the subdirectory extensions.

common/flatpak-run.c

@@ -2191,10 +2191,12 @@ flatpak_run_add_extension_args (GPtrArray    *argv_array,
       g_autofree char *full_directory = g_build_filename (directory, ext->subdir_suffix, NULL);
       g_autofree char *ref = g_build_filename (full_directory, ".ref", NULL);
       g_autofree char *real_ref = g_build_filename (ext->files_path, ext->directory, ".ref", NULL);
+      int i;
 
       if (ext->needs_tmpfs)
         {
           g_autofree char *parent = g_path_get_dirname (directory);
+
           if (g_hash_table_lookup (mounted_tmpfs, parent) == NULL)
             {
               add_args (argv_array,
@@ -2226,6 +2228,27 @@ flatpak_run_add_extension_args (GPtrArray    *argv_array,
 
           *envp_p = g_environ_setenv (*envp_p, "LD_LIBRARY_PATH", new_ld_path , TRUE);
         }
+
+      for (i = 0; ext->merge_dirs != NULL && ext->merge_dirs[i] != NULL; i++)
+        {
+          g_autofree char *parent = g_path_get_dirname (directory);
+          g_autofree char *merge_dir = g_build_filename (parent, ext->merge_dirs[i], NULL);
+          g_autofree char *source_dir = g_build_filename (ext->files_path, ext->merge_dirs[i], NULL);
+          g_auto(GLnxDirFdIterator) source_iter = { 0 };
+          struct dirent *dent;
+
+          if (glnx_dirfd_iterator_init_at (AT_FDCWD, source_dir, TRUE, &source_iter, NULL))
+            {
+              while (glnx_dirfd_iterator_next_dent (&source_iter, &dent, NULL, NULL) && dent != NULL)
+                {
+                  g_autofree char *symlink_path = g_build_filename (merge_dir, dent->d_name, NULL);
+                  g_autofree char *symlink = g_build_filename (directory, ext->merge_dirs[i], dent->d_name, NULL);
+                  add_args (argv_array,
+                            "--symlink", symlink, symlink_path,
+                            NULL);
+                }
+            }
+        }
     }
 
   g_list_free_full (extensions, (GDestroyNotify) flatpak_extension_free);

common/flatpak-utils.c

@@ -3452,6 +3452,7 @@ flatpak_extension_free (FlatpakExtension *extension)
   g_free (extension->files_path);
   g_free (extension->add_ld_path);
   g_free (extension->subdir_suffix);
+  g_strfreev (extension->merge_dirs);
   g_free (extension);
 }
 
@@ -3472,6 +3473,7 @@ flatpak_extension_new (const char *id,
                        const char *directory,
                        const char *add_ld_path,
                        const char *subdir_suffix,
+                       char **merge_dirs,
                        GFile *files,
                        gboolean is_unmaintained)
 {
@@ -3484,6 +3486,7 @@ flatpak_extension_new (const char *id,
   ext->files_path = g_file_get_path (files);
   ext->add_ld_path = g_strdup (add_ld_path);
   ext->subdir_suffix = g_strdup (subdir_suffix);
+  ext->merge_dirs = g_strdupv (merge_dirs);
   ext->is_unmaintained = is_unmaintained;
 
   if (is_unmaintained)
@@ -3526,6 +3529,7 @@ flatpak_list_extensions (GKeyFile   *metakey,
           g_autofree char *directory = g_key_file_get_string (metakey, groups[i], "directory", NULL);
           g_autofree char *version = g_key_file_get_string (metakey, groups[i], "version", NULL);
           g_autofree char *add_ld_path = g_key_file_get_string (metakey, groups[i], "add-ld-path", NULL);
+          g_auto(GStrv) merge_dirs = g_key_file_get_string_list (metakey, groups[i], "merge-dirs", NULL, NULL);
           g_autofree char *subdir_suffix = g_key_file_get_string (metakey, groups[i], "subdirectory-suffix", NULL);
           g_autofree char *ref = NULL;
           const char *branch;
@@ -3552,7 +3556,7 @@ flatpak_list_extensions (GKeyFile   *metakey,
           /* Prefer a full extension (org.freedesktop.Locale) over subdirectory ones (org.freedesktop.Locale.sv) */
           if (files != NULL)
             {
-              ext = flatpak_extension_new (extension, extension, ref, directory, add_ld_path, subdir_suffix, files, is_unmaintained);
+              ext = flatpak_extension_new (extension, extension, ref, directory, add_ld_path, subdir_suffix, merge_dirs, files, is_unmaintained);
               res = g_list_prepend (res, ext);
             }
           else if (g_key_file_get_boolean (metakey, groups[i],
@@ -3573,7 +3577,7 @@ flatpak_list_extensions (GKeyFile   *metakey,
 
                   if (subdir_files)
                     {
-                      ext = flatpak_extension_new (extension, refs[j], dir_ref, extended_dir, add_ld_path, subdir_suffix, subdir_files, FALSE);
+                      ext = flatpak_extension_new (extension, refs[j], dir_ref, extended_dir, add_ld_path, subdir_suffix, merge_dirs, subdir_files, FALSE);
                       ext->needs_tmpfs = TRUE;
                       res = g_list_prepend (res, ext);
                     }
@@ -3589,7 +3593,7 @@ flatpak_list_extensions (GKeyFile   *metakey,
 
                   if (subdir_files)
                     {
-                      ext = flatpak_extension_new (extension, unmaintained_refs[j], dir_ref, extended_dir, add_ld_path, subdir_suffix, subdir_files, TRUE);
+                      ext = flatpak_extension_new (extension, unmaintained_refs[j], dir_ref, extended_dir, add_ld_path, subdir_suffix, merge_dirs, subdir_files, TRUE);
                       ext->needs_tmpfs = TRUE;
                       res = g_list_prepend (res, ext);
                     }

common/flatpak-utils.h

@@ -326,6 +326,7 @@ typedef struct
   char *files_path;
   char *subdir_suffix;
   char *add_ld_path;
+  char **merge_dirs;
   int priority;
   gboolean needs_tmpfs;
   gboolean is_unmaintained;