[PATCH] Don't abort if swrast library is not present

[Daniel Drake]

GLX is enabled by default, but the current swrast behaviour causes X
to abort with fatal error if the swrast dri library dlopen fails.

Handle the case where the swrast library is not present, and do not
register the GLX extension unless at least one screen has a usable
GL provider.

---
 glx/glxdriswrast.c |    6 ++++++
 glx/glxext.c       |   37 ++++++++++++++++++++++++-------------
 2 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/glx/glxdriswrast.c b/glx/glxdriswrast.c
index cf4827e..20c39ab 100644
--- a/glx/glxdriswrast.c
+++ b/glx/glxdriswrast.c
@@ -468,6 +468,12 @@ __glXDRIscreenProbe(ScreenPtr pScreen)
 
     screen->driver = dlopen(filename, RTLD_LAZY | RTLD_LOCAL);
     if (screen->driver == NULL) {
+	if (errno == ENOENT) {
+	    xfree(screen);
+	    LogMessage(X_INFO, "AIGLX: swrast library %s not found\n",
+		       filename);
+	    return NULL;
+	}
 	LogMessage(X_ERROR, "AIGLX error: dlopen of %s failed (%s)\n",
 		   filename, dlerror());
         goto handle_error;
diff --git a/glx/glxext.c b/glx/glxext.c
index 13c65da..6ba404f 100644
--- a/glx/glxext.c
+++ b/glx/glxext.c
@@ -279,6 +279,7 @@ void GlxExtensionInit(void)
     ScreenPtr pScreen;
     int i;
     __GLXprovider *p;
+    Bool glx_provided = False;
 
     __glXContextRes = CreateNewResourceType((DeleteType)ContextGone);
     __glXDrawableRes = CreateNewResourceType((DeleteType)DrawableGone);
@@ -289,6 +290,29 @@ void GlxExtensionInit(void)
     if (!AddCallback (&ClientStateCallback, glxClientCallback, 0))
 	return;
 
+    for (i = 0; i < screenInfo.numScreens; i++) {
+	pScreen = screenInfo.screens[i];
+
+	for (p = __glXProviderStack; p != NULL; p = p->next) {
+	    if (p->screenProbe(pScreen) != NULL) {
+		LogMessage(X_INFO,
+			   "GLX: Initialized %s GL provider for screen %d\n",
+			   p->name, i);
+		break;
+	    }
+	}
+
+	if (!p)
+	    LogMessage(X_INFO,
+		       "GLX: no usable GL providers found for screen %d\n", i);
+	else
+	    glx_provided = True;
+    }
+
+    /* don't register extension if GL is not provided on any screen */
+    if (!glx_provided)
+	return;
+
     /*
     ** Add extension to server extensions.
     */
@@ -306,19 +330,6 @@ void GlxExtensionInit(void)
     }
 
     __glXErrorBase = extEntry->errorBase;
-
-    for (i = 0; i < screenInfo.numScreens; i++) {
-	pScreen = screenInfo.screens[i];
-
-	for (p = __glXProviderStack; p != NULL; p = p->next) {
-	    if (p->screenProbe(pScreen) != NULL) {
-		LogMessage(X_INFO,
-			   "GLX: Initialized %s GL provider for screen %d\n",
-			   p->name, i);
-	    	break;
-	    }
-	}
-    }
 }
 
 /************************************************************************/
-- 
1.5.5.1