tests: Don't redirect /tmp/dbus-* to $LIGHTDM_TEST_ROOT/tmp/dbus-*

1 files changed, 21 insertions, 0 deletions

diff --git a/tests/src/libsystem.c b/tests/src/libsystem.c
index 1c68dc10..a02cfa12 100644
--- a/tests/src/libsystem.c
+++ b/tests/src/libsystem.c
@@ -207,6 +207,27 @@ redirect_path (const gchar *path)
     if (g_str_has_prefix (path, BUILDDIR))
         return g_strdup (path);
 
+    /*
+     * Don't redirect /tmp/dbus-* so that the test runner and its invoked
+     * LightDM can interact with the D-Bus daemon launched by dbus-env.c.  The
+     * D-Bus config has <listen>unix:tmpdir=/tmp</listen>, and with that config
+     * the D-Bus specification [1] says that the daemon will create a socket
+     * whose name matches /tmp/dbus-*.
+     *
+     * (With unix:tmpdir, dbus-daemon is allowed, but not required, to create
+     * abstract sockets instead of file-based sockets.  Abstract sockets are
+     * unaffected by the redirection of /tmp to $LIGHTDM_TEST_ROOT because they
+     * don't actually exist in the filesystem.  An exception is required here
+     * anyway because not all systems support abstract sockets, and starting
+     * with v1.15.2 dbus-daemon doesn't use abstract sockets even on systems
+     * that support them [2].)
+     *
+     * [1] https://dbus.freedesktop.org/doc/dbus-specification.html#transports-unix-domain-sockets-addresses
+     * [2] https://gitlab.freedesktop.org/dbus/dbus/-/blob/35ade3c8f7aca16d1c6289828a2597859d1c503b/NEWS#L129-L147
+     */
+    if (g_str_has_prefix (path, "/tmp/dbus-"))
+        return g_strdup (path);
+
     if (g_str_has_prefix (path, "/tmp"))
         return g_build_filename (g_getenv ("LIGHTDM_TEST_ROOT"), "tmp", path + strlen ("/tmp"), NULL);