rcxml: avoid crash when checking environment for WLR_DRM_NO_ATOMIC

diff --git a/src/config/rcxml.c b/src/config/rcxml.c
index fd6fd0433704c56808afe95d735f31db414f1cf9..335374234d181cd04abdc246fe2df51f4c9d1994 100644 (file)
--- a/src/config/rcxml.c
+++ b/src/config/rcxml.c
@@ -742,9 +742,12 @@ entry(xmlNode *node, char *nodename, char *content)
                set_adaptive_sync_mode(content, &rc.adaptive_sync);
        } else if (!strcasecmp(nodename, "allowTearing.core")) {
                set_bool(content, &rc.allow_tearing);
-               if (rc.allow_tearing && strcmp(getenv("WLR_DRM_NO_ATOMIC"), "1")) {
-                       rc.allow_tearing = false;
-                       wlr_log(WLR_INFO, "WLR_DRM_NO_ATOMIC is not 1, tearing disabled");
+               if (rc.allow_tearing) {
+                       char *no_atomic_env = getenv("WLR_DRM_NO_ATOMIC");
+                       if (!no_atomic_env || strcmp(no_atomic_env, "1") != 0) {
+                               rc.allow_tearing = false;
+                               wlr_log(WLR_ERROR, "tearing requires WLR_DRM_NO_ATOMIC=1");
+                       }
                }
        } else if (!strcasecmp(nodename, "reuseOutputMode.core")) {
                set_bool(content, &rc.reuse_output_mode);