From 6b66efe873edb95ab49e73fdba74d01cba3f5153 Mon Sep 17 00:00:00 2001
From: Benjamin Otte <otte@redhat.com>
Date: Tue, 12 Apr 2011 02:50:25 +0200
Subject: [PATCH] cssprovider: Add recursion checks for @import

This is pretty important, because otherwise recursions cause crashes.
And if you accidentally change your theme to one that crashes on load,
all your gonna SEGV and then on reboot, gdm tries to load the theme...
---
 gtk/gtkcssprovider.c | 42 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 36 insertions(+), 6 deletions(-)

diff --git a/gtk/gtkcssprovider.c b/gtk/gtkcssprovider.c
index 5e0d02f990..e785ed58f8 100644
--- a/gtk/gtkcssprovider.c
+++ b/gtk/gtkcssprovider.c
@@ -1238,6 +1238,23 @@ gtk_css_scanner_get_base_url (GScanner *scanner)
   return priv->base;
 }
 
+static gboolean
+gtk_css_scanner_would_recurse (GScanner *scanner,
+                               GFile    *file)
+{
+  while (scanner)
+    {
+      GtkCssScannerPrivate *priv = scanner->user_data;
+
+      if (priv->file && g_file_equal (priv->file, file))
+        return TRUE;
+
+      scanner = priv->parent;
+    }
+
+  return FALSE;
+}
+
 static void
 gtk_css_provider_init (GtkCssProvider *css_provider)
 {
@@ -2282,12 +2299,25 @@ parse_rule (GtkCssProvider  *css_provider,
               return ';';
             }
 
-          /* FIXME: Avoid recursive importing */
-          gtk_css_provider_load_internal (css_provider,
-                                          scanner,
-                                          actual,
-                                          NULL, 0,
-                                          NULL);
+          if (gtk_css_scanner_would_recurse (scanner, actual))
+            {
+              char *path = g_file_get_path (actual);
+              gtk_css_provider_error (css_provider,
+                                      scanner,
+                                      GTK_CSS_PROVIDER_ERROR,
+                                      GTK_CSS_PROVIDER_ERROR_IMPORT,
+                                      "Loading '%s' would recurse",
+                                      path);
+              g_free (path);
+            }
+          else
+            {
+              gtk_css_provider_load_internal (css_provider,
+                                              scanner,
+                                              actual,
+                                              NULL, 0,
+                                              NULL);
+            }
 
           g_object_unref (actual);