Don't just segfault on failed compositor connections

apps/about.c

@@ -84,6 +84,10 @@ static void init_default(void) {
 int main(int argc, char * argv[]) {
 	int req_center_x, req_center_y;
 	yctx = yutani_init();
+	if (!yctx) {
+		fprintf(stderr, "%s: failed to connect to compositor\n", argv[0]);
+		return 1;
+	}
 	init_decorations();
 
 	window = yutani_window_create(yctx, width + decor_width(), height + decor_height());

apps/background.c

@@ -54,6 +54,10 @@ int main (int argc, char ** argv) {
 	wallpaper->alpha = 0;
 
 	yctx = yutani_init();
+	if (!yctx) {
+		fprintf(stderr, "%s: failed to connect to compositor\n", argv[0]);
+		return 1;
+	}
 
 	/* wallpaper */
 	wallpaper_window = yutani_window_create(yctx, yctx->display_width, yctx->display_height);

apps/drawlines.c

@@ -1,24 +1,21 @@
-/* This file is part of ToaruOS and is released under the terms
+/* vim: ts=4 sw=4 noexpandtab
+ * This file is part of ToaruOS and is released under the terms
  * of the NCSA / University of Illinois License - see LICENSE.md
  * Copyright (C) 2013-2018 K. Lange
- */
-/*
- * drawlines
  *
- * Test application to draw lines to a window.
+ * Yutani demo application that draws lines into a window.
+ *
  */
 #include <stdlib.h>
 #include <assert.h>
 #include <syscall.h>
 #include <unistd.h>
 #include <pthread.h>
+#include <time.h>
 
 #include <toaru/yutani.h>
 #include <toaru/graphics.h>
 
-#define TRACE_APP_NAME "drawlines"
-#include <toaru/trace.h>
-
 static int left, top, width, height;
 
 static yutani_t * yctx;
@@ -45,16 +42,16 @@ int main (int argc, char ** argv) {
 
 	srand(time(NULL));
 
-	TRACE("Starting drawlines.");
 	yctx = yutani_init();
-	TRACE("Creating a window.");
+	if (!yctx) {
+		fprintf(stderr, "%s: failed to connect to compositor\n", argv[0]);
+		return 1;
+	}
+
 	wina = yutani_window_create(yctx, width, height);
-	TRACE("Move.");
 	yutani_window_move(yctx, wina, left, top);
-	TRACE("Advertise icon.");
 	yutani_window_advertise_icon(yctx, wina, "drawlines", "drawlines");
 
-	TRACE("Init graphics.");
 	ctx = init_graphics_yutani(wina);
 	draw_fill(ctx, rgb(0,0,0));
 

apps/julia.c

@@ -1,8 +1,8 @@
-/* This file is part of ToaruOS and is released under the terms
+/* vim: ts=4 sw=4 noexpandtab
+ * This file is part of ToaruOS and is released under the terms
  * of the NCSA / University of Illinois License - see LICENSE.md
  * Copyright (C) 2013-2018 K. Lange
- */
-/*
+ *
  * Julia Fractal Generator
  *
  * This is the updated windowed version of the
@@ -242,6 +242,10 @@ int main(int argc, char * argv[]) {
 	}
 
 	yctx = yutani_init();
+	if (!yctx) {
+		fprintf(stderr, "%s: failed to connect to compositor\n", argv[0]);
+		return 1;
+	}
 	init_decorations();
 
 	window = yutani_window_create(yctx, width + decor_width(), height + decor_height());

apps/plasma.c

@@ -1,11 +1,11 @@
-/* This file is part of ToaruOS and is released under the terms
+/* vim: ts=4 sw=4 noexpandtab
+ * This file is part of ToaruOS and is released under the terms
  * of the NCSA / University of Illinois License - see LICENSE.md
  * Copyright (C) 2013-2018 K. Lange
- */
-/*
- * test-gfx
  *
- * Windowed graphical test application.
+ * Plasma
+ *
+ * Draws animated plasma in a decorated window.
  */
 #include <stdlib.h>
 #include <assert.h>
@@ -102,6 +102,10 @@ void resize_finish(int w, int h) {
 
 int main (int argc, char ** argv) {
 	yctx = yutani_init();
+	if (!yctx) {
+		fprintf(stderr, "%s: failed to connect to compositor\n", argv[0]);
+		return 1;
+	}
 
 	win_width  = 300;
 	win_height = 300;

apps/terminal.c

@@ -1925,6 +1925,11 @@ int main(int argc, char ** argv) {
 	/* Initialize the windowing library */
 	yctx = yutani_init();
 
+	if (!yctx) {
+		fprintf(stderr, "%s: failed to connect to compositor\n", argv[0]);
+		return 1;
+	}
+
 	if (_fullscreen) {
 		window_width = yctx->display_width;
 		window_height = yctx->display_height;