thunderbolt: new panel for device management

Thunderbolt devices need to be approved before they can be used.
This is done via the boltd system daemon and gnome-shell. The new
panel enables the user to manage thunderbolt devices, i.e.:

 - forget devices that have previously been authorized
 - authorize currently unauthorize devices

Additionally authorization of devices an be temporarily disabled
to ensure no evil device will gain access to the computers
resources.

File starting with "bolt-" are copied from bolt's source tree
and currently correspond to the bolt upstream commit with the id
f22b1cd6104bdc2b33a95d9896b50f29a141b8d8
They can be updated from bolt via the update-from-bolt.sh script.

panels/thunderbolt/bolt-str.c

@@ -0,0 +1,117 @@
+/*
+ * Copyright © 2017 Red Hat, Inc
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *       Christian J. Kellner <christian@kellner.me>
+ */
+
+#include "config.h"
+
+#include "bolt-str.h"
+
+#include <string.h>
+
+typedef void (* zero_fn_t) (void  *s,
+                            size_t n);
+void
+bolt_erase_n (void *data, gsize n)
+{
+#if !HAVE_FN_EXPLICIT_BZERO
+  #warning no explicit bzero, using fallback
+  static volatile zero_fn_t explicit_bzero = bzero;
+#endif
+
+  explicit_bzero (data, n);
+}
+
+void
+bolt_str_erase (char *str)
+{
+  if (str == NULL)
+    return;
+
+  bolt_erase_n (str, strlen (str));
+}
+
+void
+bolt_str_erase_clear (char **str)
+{
+  g_return_if_fail (str != NULL);
+  if (*str == NULL)
+    return;
+
+  bolt_str_erase (*str);
+  g_free (*str);
+  *str = NULL;
+}
+
+GStrv
+bolt_strv_from_ptr_array (GPtrArray **array)
+{
+  GPtrArray *a;
+
+  if (array == NULL || *array == NULL)
+    return NULL;
+
+  a = *array;
+
+  if (a->len == 0 || a->pdata[a->len - 1] != NULL)
+    g_ptr_array_add (a, NULL);
+
+  *array = NULL;
+  return (GStrv) g_ptr_array_free (a, FALSE);
+}
+
+char *
+bolt_strdup_validate (const char *string)
+{
+  g_autofree char *str = NULL;
+  gboolean ok;
+  gsize l;
+
+  if (string == NULL)
+    return NULL;
+
+  str = g_strdup (string);
+  str = g_strstrip (str);
+
+  l = strlen (str);
+  if (l == 0)
+    return NULL;
+
+  ok = g_utf8_validate (str, l, NULL);
+
+  if (!ok)
+    return NULL;
+
+  return g_steal_pointer (&str);
+}
+
+char *
+bolt_strstrip (char *string)
+{
+  char *str;
+
+  if (string == NULL)
+    return NULL;
+
+  str = g_strstrip (string);
+
+  if (strlen (str) == 0)
+    g_clear_pointer (&str, g_free);
+
+  return str;
+}