Check writability

contrib/apt-conf/50appstream

@@ -44,5 +44,5 @@ Acquire::IndexTargets {
 
 # Refresh AppStream cache when APT's cache is updated (i.e. apt-cache update)
 APT::Update::Post-Invoke-Success {
-    "if /usr/bin/test -e /usr/bin/appstreamcli; then appstreamcli refresh > /dev/null; fi";
+    "if /usr/bin/test -w /var/cache/app-info -a -w /var/lib/app-info -a -e /usr/bin/appstreamcli; then appstreamcli refresh > /dev/null; fi";
 };

src/as-cache-builder.c

@@ -149,7 +149,9 @@ as_cache_builder_setup (AsCacheBuilder *builder, const gchar *dbpath)
 	as_cache_builder_check_cache_ctime (builder);
 
 	/* try to create db directory, in case it doesn't exist */
-	g_mkdir_with_parents (priv->db_path, 0755);
+	if (g_mkdir_with_parents (priv->db_path, 0755) < 0 ||
+		!as_utils_is_writable (priv->db_path))
+		return FALSE;
 
 	ret = xa_database_write_initialize (priv->db_w, priv->db_path);
 	return ret;
@@ -293,9 +295,15 @@ as_cache_builder_scan_apt (AsCacheBuilder *builder, gboolean force, GError **err
 	guint i;
 	AsCacheBuilderPrivate *priv = GET_PRIVATE (builder);
 
-	/* we can't do anything here if we're not root */
-	if (!as_utils_is_root ())
+	/* we can't do anything here if we can't write to the target directories */
+	if (!as_utils_is_writable (appstream_yml_target) || !as_utils_is_writable (appstream_icons_target))
+	{
+		g_set_error (error,
+				AS_CACHE_BUILDER_ERROR,
+				AS_CACHE_BUILDER_ERROR_UNWRITABLE_DEST,
+				_("Cannot write to destination directory."));
 		return;
+	}
 
 	/* skip this step if the APT lists directory doesn't exist */
 	if (!g_file_test (apt_lists_dir, G_FILE_TEST_IS_DIR)) {
@@ -441,6 +449,14 @@ as_cache_builder_refresh (AsCacheBuilder *builder, gboolean force, GError **erro
 	if (tmp_error != NULL) {
 		/* the exact error is not forwarded here, since we might be able to partially update the cache */
 		g_warning ("Error while collecting metadata: %s", tmp_error->message);
+		if (g_error_matches (tmp_error,
+			AS_CACHE_BUILDER_ERROR,
+			AS_CACHE_BUILDER_ERROR_UNWRITABLE_DEST))
+		{
+			GError *err = g_error_copy (tmp_error);
+			*error = err;
+			return FALSE;
+		}
 		g_error_free (tmp_error);
 		tmp_error = NULL;
 	}

src/as-cache-builder.h

@@ -56,6 +56,7 @@ GQuark as_cache_builder_error_quark (void);
 typedef enum {
 	AS_CACHE_BUILDER_ERROR_FAILED,
 	AS_CACHE_BUILDER_ERROR_PARTIALLY_FAILED,
+	AS_CACHE_BUILDER_ERROR_UNWRITABLE_DEST,
 	/*< private >*/
 	AS_CACHE_BUILDER_ERROR_LAST
 } AsCacheBuilderError;

src/as-utils-private.h

@@ -42,6 +42,8 @@ GPtrArray		*as_utils_find_files (const gchar *dir,
 
 gboolean		as_utils_is_root (void);
 
+gboolean		as_utils_is_writable (const gchar *path);
+
 gchar			*as_str_replace (const gchar *str,
 					 const gchar *old_str,
 					 const gchar *new_str);

src/as-utils.c

@@ -419,6 +419,34 @@ as_utils_is_root (void)
 	return (vuid == ((uid_t) 0));
 }
 
+/**
+ * as_utils_is_writable:
+ * @path: the path to check.
+ *
+ * Checks if a path is writable.
+ */
+gboolean
+as_utils_is_writable (const gchar *path)
+{
+	g_autoptr(GFile) file;
+	g_autoptr(GFileInfo) file_info;
+
+	file = g_file_new_for_path (path);
+
+	file_info = g_file_query_info (
+		file,
+		G_FILE_ATTRIBUTE_ACCESS_CAN_WRITE,
+		G_FILE_QUERY_INFO_NONE,
+		NULL,
+		NULL);
+
+	if (file_info && g_file_info_has_attribute (file_info, G_FILE_ATTRIBUTE_ACCESS_CAN_WRITE))
+		return g_file_info_get_attribute_boolean (file_info, G_FILE_ATTRIBUTE_ACCESS_CAN_WRITE);
+
+	return FALSE;
+}
+
+
 /**
  * as_get_current_locale:
  *

tools/ascli-mdata-actions.c

@@ -25,6 +25,7 @@
 #include <stdio.h>
 #include "ascli-utils.h"
 #include "as-cache-builder.h"
+#include "as-settings-private.h"
 
 /**
  * ascli_refresh_cache:
@@ -36,13 +37,6 @@ ascli_refresh_cache (const gchar *dbpath, const gchar *datapath, gboolean forced
 	g_autoptr(GError) error = NULL;
 	gboolean ret;
 
-	if (dbpath == NULL) {
-		if (getuid () != ((uid_t) 0)) {
-			g_print ("%s\n", _("You need to run this command with superuser permissions!"));
-			return 2;
-		}
-	}
-
 	cbuilder = as_cache_builder_new ();
 
 	if (datapath != NULL) {
@@ -54,7 +48,12 @@ ascli_refresh_cache (const gchar *dbpath, const gchar *datapath, gboolean forced
 		g_strfreev (strv);
 	}
 
-	as_cache_builder_setup (cbuilder, dbpath);
+	ret = as_cache_builder_setup (cbuilder, dbpath);
+	if (!ret)
+	{
+		g_printerr ("Can't write to %s\n", dbpath ? dbpath : AS_APPSTREAM_CACHE_PATH);
+		return 2;
+	}
 	ret = as_cache_builder_refresh (cbuilder, forced, &error);
 
 	if (ret) {