Merge pull request #31 from step-/fix-two-race-conditions

src/main.c

@@ -39,7 +39,6 @@ static GtkWidget *dialog = NULL;
 static gint ret = YAD_RESPONSE_ESC;
 
 YadNTabs *tabs;
-gint t_sem;
 
 #ifndef G_OS_WIN32
 static void
@@ -676,6 +675,10 @@ create_plug (void)
       usleep (1000);
       tabs = get_tabs (options.plug, FALSE);
     }
+  while (!tabs[0].xid)
+    {
+      usleep (1000);
+    }
 
   win = gtk_plug_new (0);
   /* set window borders */
@@ -690,10 +693,9 @@ create_plug (void)
   gtk_widget_show_all (win);
 
   /* add plug data */
+  /* notebook/paned will count non-zero xids */
   tabs[options.tabnum].pid = getpid ();
   tabs[options.tabnum].xid = gtk_plug_get_id (GTK_PLUG (win));
-  /* FIXME: may be a race here */
-  tabs[0].xid++;
   shmdt (tabs);
 }
 

src/notebook.c

@@ -77,12 +77,24 @@ void
 notebook_swallow_childs (void)
 {
   guint i, n_tabs;
+  gboolean all_registered;
 
   n_tabs = g_slist_length (options.notebook_data.tabs);
 
-  /* wait until all children are register */
-  while (tabs[0].xid != n_tabs)
-    usleep (1000);
+  /* wait until all children are registered */
+  do
+    {
+      all_registered = TRUE;
+      for (i = 1; i <= n_tabs; i++)
+        if (!tabs[i].xid)
+          {
+            all_registered = FALSE;
+            break;
+          }
+      if (!all_registered)
+        usleep (1000);
+    }
+  while (!all_registered);
 
   for (i = 1; i <= n_tabs; i++)
     {
@@ -117,7 +129,7 @@ notebook_close_childs (void)
 {
   guint i, n_tabs;
   struct shmid_ds buf;
-  gboolean is_running = TRUE;
+  gboolean is_running;
 
   n_tabs = g_slist_length (options.notebook_data.tabs);
   for (i = 1; i <= n_tabs; i++)
@@ -127,7 +139,7 @@ notebook_close_childs (void)
     }
 
   /* wait for stop subprocesses */
-  while (is_running)
+  do
     {
       is_running = FALSE;
       for (i = 1; i <= n_tabs; i++)
@@ -138,8 +150,10 @@ notebook_close_childs (void)
               break;
             }
         }
-      usleep (1000);
+      if (is_running)
+        usleep (1000);
     }
+  while (is_running);
 
   /* cleanup shared memory */
   shmctl (tabs[0].pid, IPC_RMID, &buf);

src/paned.c

@@ -77,8 +77,8 @@ paned_swallow_childs (void)
   s1 = GTK_WIDGET (g_object_get_data (G_OBJECT (paned), "s1"));
   s2 = GTK_WIDGET (g_object_get_data (G_OBJECT (paned), "s2"));
 
-  /* wait until all children are register */
-  while (tabs[0].xid != 2)
+  /* wait until all children are registered */
+  while (!tabs[1].xid || !tabs[2].xid)
     usleep (1000);
 
   if (tabs[1].pid != -1)

src/util.c

@@ -370,6 +370,8 @@ get_tabs (key_t key, gboolean create)
           t[i].xid = 0;
         }
       t[0].pid = shmid;
+      /* lastly, allow plugs to write shmem */
+      t[0].xid = 1;
     }
 
   return t;

src/yad.h

@@ -559,9 +559,8 @@ typedef struct {
 /* pointer to shared memory for tabbed dialog */
 /* 0 item used for special info: */
 /*   pid - memory id */
-/*   xid - count of registered tabs (for sync) */
+/*   xid - allow plugs to write shmem (for sync) */
 extern YadNTabs *tabs;
-extern gint t_sem;
 
 void yad_options_init (void);
 GOptionContext *yad_create_context (void);