override: Support global overrides

This lets you add overrides that affect all applications. Application
overrides have higher priority so will override the global overrides.

Closes: #1245
Approved by: alexlarsson

3 files changed, 52 insertions, 16 deletions

diff --git a/app/flatpak-builtins-override.c b/app/flatpak-builtins-override.c
index 1e24a65c..c971a9db 100644
--- a/app/flatpak-builtins-override.c
+++ b/app/flatpak-builtins-override.c
@@ -51,7 +51,7 @@ flatpak_builtin_override (int argc, char **argv, GCancellable *cancellable, GErr
   g_autoptr(FlatpakContext) overrides = NULL;
   g_autoptr(GError) my_error = NULL;
 
-  context = g_option_context_new (_("APP - Override settings for application"));
+  context = g_option_context_new (_("[APP] - Override settings [for application]"));
   g_option_context_set_translation_domain (context, GETTEXT_PACKAGE);
 
   arg_context = flatpak_context_new ();
@@ -64,16 +64,17 @@ flatpak_builtin_override (int argc, char **argv, GCancellable *cancellable, GErr
 
   dir = g_ptr_array_index (dirs, 0);
 
-  if (argc < 2)
-    return usage_error (context, _("APP must be specified"), error);
-
   if (argc > 2)
     return usage_error (context, _("Too many arguments"), error);
 
-  app = argv[1];
-
-  if (!flatpak_is_valid_name (app, &my_error))
-    return flatpak_fail (error, _("'%s' is not a valid application name: %s"), app, my_error->message);
+  if (argc >= 2)
+    {
+      app = argv[1];
+      if (!flatpak_is_valid_name (app, &my_error))
+        return flatpak_fail (error, _("'%s' is not a valid application name: %s"), app, my_error->message);
+    }
+  else
+    app = NULL;
 
   metakey = flatpak_load_override_keyfile (app, flatpak_dir_is_user (dir), &my_error);
   if (metakey == NULL)
diff --git a/common/flatpak-dir.c b/common/flatpak-dir.c
index d4b4285c..2ac25e6a 100644
--- a/common/flatpak-dir.c
+++ b/common/flatpak-dir.c
@@ -149,6 +149,8 @@ struct FlatpakDeploy
   GKeyFile       *metadata;
   FlatpakContext *system_overrides;
   FlatpakContext *user_overrides;
+  FlatpakContext *system_app_overrides;
+  FlatpakContext *user_app_overrides;
 };
 
 typedef struct
@@ -242,6 +244,8 @@ flatpak_deploy_finalize (GObject *object)
   g_clear_pointer (&self->metadata, g_key_file_unref);
   g_clear_pointer (&self->system_overrides, flatpak_context_free);
   g_clear_pointer (&self->user_overrides, flatpak_context_free);
+  g_clear_pointer (&self->system_app_overrides, flatpak_context_free);
+  g_clear_pointer (&self->user_app_overrides, flatpak_context_free);
 
   G_OBJECT_CLASS (flatpak_deploy_parent_class)->finalize (object);
 }
@@ -319,9 +323,15 @@ flatpak_deploy_get_overrides (FlatpakDeploy *deploy)
   if (deploy->system_overrides)
     flatpak_context_merge (overrides, deploy->system_overrides);
 
+  if (deploy->system_app_overrides)
+    flatpak_context_merge (overrides, deploy->system_app_overrides);
+
   if (deploy->user_overrides)
     flatpak_context_merge (overrides, deploy->user_overrides);
 
+  if (deploy->user_app_overrides)
+    flatpak_context_merge (overrides, deploy->user_app_overrides);
+
   return overrides;
 }
 
@@ -1018,7 +1028,11 @@ flatpak_dir_load_override (FlatpakDir *self,
   char *metadata_contents;
 
   override_dir = g_file_get_child (self->basedir, "overrides");
-  file = g_file_get_child (override_dir, app_id);
+
+  if (app_id)
+    file = g_file_get_child (override_dir, app_id);
+  else
+    file = g_file_get_child (override_dir, "global");
 
   if (!g_file_load_contents (file, NULL,
                              &metadata_contents, length, NULL, NULL))
@@ -1099,7 +1113,11 @@ flatpak_save_override_keyfile (GKeyFile   *metakey,
     base_dir = flatpak_get_system_default_base_dir_location ();
 
   override_dir = g_file_get_child (base_dir, "overrides");
-  file = g_file_get_child (override_dir, app_id);
+
+  if (app_id)
+    file = g_file_get_child (override_dir, app_id);
+  else
+    file = g_file_get_child (override_dir, "global");
 
   filename = g_file_get_path (file);
   parent = g_path_get_dirname (filename);
@@ -1153,20 +1171,33 @@ flatpak_dir_load_deployed (FlatpakDir   *self,
   ref_parts = g_strsplit (ref, "/", -1);
   g_assert (g_strv_length (ref_parts) == 4);
 
-  /* Only apps have overrides */
+  /* Only load system global overrides for system installed apps */
+  if (!self->user)
+    {
+      deploy->system_overrides = flatpak_load_override_file (NULL, FALSE, error);
+      if (deploy->system_overrides == NULL)
+        return NULL;
+    }
+
+  /* Always load user global overrides */
+  deploy->user_overrides = flatpak_load_override_file (NULL, TRUE, error);
+  if (deploy->user_overrides == NULL)
+    return NULL;
+
+  /* Only apps have app overrides */
   if (strcmp (ref_parts[0], "app") == 0)
     {
       /* Only load system overrides for system installed apps */
       if (!self->user)
         {
-          deploy->system_overrides = flatpak_load_override_file (ref_parts[1], FALSE, error);
-          if (deploy->system_overrides == NULL)
+          deploy->system_app_overrides = flatpak_load_override_file (ref_parts[1], FALSE, error);
+          if (deploy->system_app_overrides == NULL)
             return NULL;
         }
 
       /* Always load user overrides */
-      deploy->user_overrides = flatpak_load_override_file (ref_parts[1], TRUE, error);
-      if (deploy->user_overrides == NULL)
+      deploy->user_app_overrides = flatpak_load_override_file (ref_parts[1], TRUE, error);
+      if (deploy->user_app_overrides == NULL)
         return NULL;
     }
 
diff --git a/doc/flatpak-override.xml b/doc/flatpak-override.xml
index 86757b37..b5ce3784 100644
--- a/doc/flatpak-override.xml
+++ b/doc/flatpak-override.xml
@@ -32,7 +32,7 @@
             <cmdsynopsis>
                 <command>flatpak override</command>
                 <arg choice="opt" rep="repeat">OPTION</arg>
-                <arg choice="plain">APP</arg>
+                <arg choice="opt">APP</arg>
             </cmdsynopsis>
     </refsynopsisdiv>
 
@@ -50,6 +50,10 @@
             flatpak run, or every time by using flatpak override.
         </para>
         <para>
+            If the application id is not specified then the overrides affect all applications,
+            but the per-application overrides can override the global overrides.
+        </para>
+        <para>
             Unless overridden with the --user or --installation options, this command
             changes the default system-wide installation.
         </para>