Attachment 516774 Details for Bug 576933

[patch] use a separate display to make protocol requests within X error handler

separate.display.in.error (text/plain), 3.15 KB, created by Karl Tomlinson (:karlt)

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Creator: Karl Tomlinson (:karlt)

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patch

obsolete

># HG changeset patch
># Parent aa0d8fc9ae57f62bacc683313149bae17d9237ad
>b=576933 use a separate display to make protocol requests within X error handler r?roc
>
>diff --git a/toolkit/xre/nsX11ErrorHandler.cpp b/toolkit/xre/nsX11ErrorHandler.cpp
>--- a/toolkit/xre/nsX11ErrorHandler.cpp
>+++ b/toolkit/xre/nsX11ErrorHandler.cpp
>@@ -50,56 +50,58 @@ using mozilla::plugins::PluginProcessChi
> 
> #include "mozilla/X11Util.h"
> #include <X11/Xlib.h>
> 
> #define BUFSIZE 2048 // What Xlib uses with XGetErrorDatabaseText
> 
> extern "C" {
> static int
>-IgnoreError(Display *display, XErrorEvent *event) {
>-  return 0; // This return value is ignored.
>-}
>-
>-static int
> X11Error(Display *display, XErrorEvent *event) {
>   nsCAutoString notes;
>   char buffer[BUFSIZE];
> 
>   // Get an indication of how long ago the request that caused the error was
>-  // made.  Do this before querying extensions etc below.
>+  // made.
>   unsigned long age = NextRequest(display) - event->serial;
> 
>-  // Ignore subsequent errors, which may get processed during the extension
>-  // queries below for example.
>-  XSetErrorHandler(IgnoreError);
>-
>   // Get a string to represent the request that caused the error.
>   nsCAutoString message;
>   if (event->request_code < 128) {
>     // Core protocol request
>     message.AppendInt(event->request_code);
>   } else {
>     // Extension request
>-    int nExts;
>-    char** extNames = XListExtensions(display, &nExts);
>-    if (extNames) {
>-      for (int i = 0; i < nExts; ++i) {
>-        int major_opcode, first_event, first_error;
>-        if (XQueryExtension(display, extNames[i],
>-                            &major_opcode, &first_event, &first_error)
>-            && major_opcode == event->request_code) {
>-          message.Append(extNames[i]);
>-          message.Append('.');
>-          message.AppendInt(event->minor_code);
>-          break;
>+
>+    // man XSetErrorHandler says "the error handler should not call any
>+    // functions (directly or indirectly) on the display that will generate
>+    // protocol requests or that will look for input events" so we use another
>+    // temporary Display to request extension information.  This assumes on
>+    // the DISPLAY environment variable has been set and matches what was used
>+    // to open |display|.
>+    Display *tmpDisplay = XOpenDisplay(NULL);
>+    if (tmpDisplay) {
>+      int nExts;
>+      char** extNames = XListExtensions(tmpDisplay, &nExts);
>+      if (extNames) {
>+        for (int i = 0; i < nExts; ++i) {
>+          int major_opcode, first_event, first_error;
>+          if (XQueryExtension(tmpDisplay, extNames[i],
>+                              &major_opcode, &first_event, &first_error)
>+              && major_opcode == event->request_code) {
>+            message.Append(extNames[i]);
>+            message.Append('.');
>+            message.AppendInt(event->minor_code);
>+            break;
>+          }
>         }
>+
>+        XFreeExtensionList(extNames);
>       }
>-
>-      XFreeExtensionList(extNames);
>+      XCloseDisplay(tmpDisplay);
>     }
>   }
> 
>   if (message.IsEmpty()) {
>     buffer[0] = '\0';
>   } else {
>     XGetErrorDatabaseText(display, "XRequest", message.get(), "",
>                           buffer, sizeof(buffer));

Flags:

roc: review+
christian: approval2.0+

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Attachments on bug 576933: 516774 | 516782 | 527377 | 527380