Use DBusString for all relocation and install-root code

This means we handle OOM correctly, and makes it obvious
that we are not overflowing buffers. This change does not
affect the actual content of the strings.

Instead of redefining DBUS_DATADIR to be a function call
(which hides the fact that DBUS_DATADIR is used),
this patch makes each use explicit: DBUS_DATADIR
is always the #define from configure or cmake, before
replacing the prefix.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=83539
Tested-by: Ralf Habacker <ralf.habacker@freenet.de>
Reviewed-by: Ralf Habacker <ralf.habacker@freenet.de>

1 files changed, 73 insertions, 60 deletions

diff --git a/dbus/dbus-sysdeps-util-win.c b/dbus/dbus-sysdeps-util-win.c
index 96100d49..71296fa8 100644
--- a/dbus/dbus-sysdeps-util-win.c
+++ b/dbus/dbus-sysdeps-util-win.c
@@ -1469,73 +1469,68 @@ _dbus_command_for_pid (unsigned long  pid,
   return FALSE;
 }
 
-/*
- * replaces the term DBUS_PREFIX in configure_time_path by the
- * current dbus installation directory. On unix this function is a noop
+/**
+ * Replace the DBUS_PREFIX in the given path, in-place, by the
+ * current D-Bus installation directory. On Unix this function
+ * does nothing, successfully.
  *
- * @param configure_time_path
- * @return real path
+ * @param path path to edit
+ * @return #FALSE on OOM
  */
-const char *
-_dbus_replace_install_prefix (const char *configure_time_path)
+dbus_bool_t
+_dbus_replace_install_prefix (DBusString *path)
 {
 #ifndef DBUS_PREFIX
-  return configure_time_path;
+  /* leave path unchanged */
+  return TRUE;
 #else
-  static char retval[1000];
-  static char runtime_prefix[1000];
-  int len = 1000;
+  DBusString runtime_prefix;
   int i;
 
-  if (!configure_time_path)
-    return NULL;
-
-  if ((!_dbus_get_install_root(runtime_prefix, len) ||
-       strncmp (configure_time_path, DBUS_PREFIX "/",
-                strlen (DBUS_PREFIX) + 1))) {
-     strncpy (retval, configure_time_path, sizeof (retval) - 1);
-     /* strncpy does not guarantee to 0-terminate the string */
-     retval[sizeof (retval) - 1] = '\0';
-  } else {
-     size_t remaining;
-
-     strncpy (retval, runtime_prefix, sizeof (retval) - 1);
-     retval[sizeof (retval) - 1] = '\0';
-     remaining = sizeof (retval) - 1 - strlen (retval);
-     strncat (retval,
-         configure_time_path + strlen (DBUS_PREFIX) + 1,
-         remaining);
-  }
+  if (!_dbus_string_init (&runtime_prefix))
+    return FALSE;
+
+  if (!_dbus_get_install_root (&runtime_prefix))
+    {
+      _dbus_string_free (&runtime_prefix);
+      return FALSE;
+    }
+
+  if (_dbus_string_get_length (&runtime_prefix) == 0)
+    {
+      /* cannot determine install root, leave path unchanged */
+      _dbus_string_free (&runtime_prefix);
+      return TRUE;
+    }
+
+  if (_dbus_string_starts_with_c_str (path, DBUS_PREFIX "/"))
+    {
+      /* Replace DBUS_PREFIX "/" with runtime_prefix.
+       * Note unusual calling convention: source is first, then dest */
+      if (!_dbus_string_replace_len (
+            &runtime_prefix, 0, _dbus_string_get_length (&runtime_prefix),
+            path, 0, strlen (DBUS_PREFIX) + 1))
+        {
+          _dbus_string_free (&runtime_prefix);
+          return FALSE;
+        }
+    }
 
   /* Somehow, in some situations, backslashes get collapsed in the string.
    * Since windows C library accepts both forward and backslashes as
    * path separators, convert all backslashes to forward slashes.
    */
 
-  for(i = 0; retval[i] != '\0'; i++) {
-    if(retval[i] == '\\')
-      retval[i] = '/';
-  }
-  return retval;
-#endif
-}
-
-/**
- * return the relocated DATADIR
- *
- * @returns relocated DATADIR static string
- */
+  for (i = 0; i < _dbus_string_get_length (path); i++)
+    {
+      if (_dbus_string_get_byte (path, i) == '\\')
+        _dbus_string_set_byte (path, i, '/');
+    }
 
-static const char *
-_dbus_windows_get_datadir (void)
-{
-	return _dbus_replace_install_prefix(DBUS_DATADIR);
+  return TRUE;
+#endif
 }
 
-#undef DBUS_DATADIR
-#define DBUS_DATADIR _dbus_windows_get_datadir ()
-
-
 #define DBUS_STANDARD_SESSION_SERVICEDIR "/dbus-1/services"
 #define DBUS_STANDARD_SYSTEM_SERVICEDIR "/dbus-1/system-services"
 
@@ -1583,23 +1578,40 @@ _dbus_get_standard_session_servicedirs (DBusList **dirs)
  the code for accessing services requires absolute base pathes
  in case DBUS_DATADIR is relative make it absolute
 */
-#ifdef DBUS_WIN
   {
     DBusString p;
 
-    _dbus_string_init_const (&p, DBUS_DATADIR);
+    if (!_dbus_string_init (&p))
+      goto oom;
+
+    if (!_dbus_string_append (&p, DBUS_DATADIR) ||
+        !_dbus_replace_install_prefix (&p))
+      {
+        _dbus_string_free (&p);
+        goto oom;
+      }
 
     if (!_dbus_path_is_absolute (&p))
       {
-        char install_root[1000];
-        if (_dbus_get_install_root (install_root, sizeof(install_root)))
-          if (!_dbus_string_append (&servicedir_path, install_root))
+        /* this only works because this is the first thing in the
+         * servicedir_path; if it wasn't, we'd have to use a temporary
+         * string and copy it in */
+        if (!_dbus_get_install_root (&servicedir_path))
+          {
+            _dbus_string_free (&p);
             goto oom;
+          }
       }
+
+    if (!_dbus_string_append (&servicedir_path,
+          _dbus_string_get_const_data (&p)))
+      {
+        _dbus_string_free (&p);
+        goto oom;
+      }
+
+    _dbus_string_free (&p);
   }
-#endif
-  if (!_dbus_string_append (&servicedir_path, DBUS_DATADIR))
-    goto oom;
 
   if (!_dbus_string_append (&servicedir_path, _DBUS_PATH_SEPARATOR))
     goto oom;
@@ -1660,7 +1672,8 @@ _dbus_get_config_file_name (DBusString *str,
 {
   DBusString tmp;
 
-  if (!_dbus_string_append (str, _dbus_windows_get_datadir ()))
+  if (!_dbus_string_append (str, DBUS_DATADIR) ||
+      !_dbus_replace_install_prefix (str))
     return FALSE;
 
   _dbus_string_init_const (&tmp, "dbus-1");