src/wl-restart: set WL_RESTART_COUNT on compositor restart

README.md

@@ -42,6 +42,7 @@ in the [KDE wiki](https://invent.kde.org/plasma/kwin/-/wikis/Restarting).
 - Restarts your compositor when it crashes
 - Don't lose your session (for programs that support seamless Wayland reconnect)
 - Configurable max number of crashes before giving up
+- Sets `WL_RESTART_COUNT` to the current restart counter on compositor restart.
 
 ## Usage
 

man/wl-restart.1.scd

@@ -62,6 +62,10 @@ If the compositor exits with any other exit code, *wl-restart* increments the
 restart counter and restarts the compositor if it is smaller than the maximum.
 Otherwise, *wl-restart* cleans up the socket and exits as well.
 
+When the compositor is restarted, *wl-restart* sets the environment variable
+*WL_RESTART_COUNT* to the restart counter, so other scripts can react to it and
+e.g. display a message or restart services that don't restart automatically.
+
 When *wl-restart* receives a *SIGINT* or *SIGTERM* signal, it kills the
 compositor with *SIGTERM* if it's currently running, cleans up the socket, and
 exits.

src/wl-restart.c

@@ -162,6 +162,17 @@ void run(ctx_t * ctx) {
             ctx->restart_counter++;
             printf("info: compositor exited with code %d, incrementing restart counter (%d)\n", status, ctx->restart_counter);
         }
+
+        // format new restart count
+        char * restart_counter_str = NULL;
+        if (asprintf(&restart_counter_str, "%d", ctx->restart_counter) == -1) {
+            printf("error: failed to convert restart counter to string\n");
+            exit_fail(ctx);
+        }
+
+        // add restart count to environment
+        setenv("WL_RESTART_COUNT", restart_counter_str, true);
+        free(restart_counter_str);
     }
 
     printf("error: too many restarts, quitting\n");