toolkit/xre/nsX11ErrorHandler.cpp

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  23  *   Karl Tomlinson <karlt+@karlt.net>
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  37  * ***** END LICENSE BLOCK ***** */
  38
  39 #include "nsX11ErrorHandler.h"
  40
  41 #ifdef MOZ_IPC
  42 #include "mozilla/plugins/PluginProcessChild.h"
  43 using mozilla::plugins::PluginProcessChild;
  44 #endif
  45
  46 #include "prenv.h"
  47 #include "nsXULAppAPI.h"
  48 #include "nsExceptionHandler.h"
  49 #include "nsDebug.h"
  50
  51 #include "mozilla/X11Util.h"
  52 #include <X11/Xlib.h>
  53
  54 #define BUFSIZE 2048 // What Xlib uses with XGetErrorDatabaseText
  55
  56 extern "C" {
  57 static int
  58 IgnoreError(Display *display, XErrorEvent *event) {
  59   return 0; // This return value is ignored.
  60 }
  61
  62 static int
  63 X11Error(Display *display, XErrorEvent *event) {
  64   nsCAutoString notes;
  65   char buffer[BUFSIZE];
  66
  67   // Get an indication of how long ago the request that caused the error was
  68   // made.  Do this before querying extensions etc below.
  69   unsigned long age = NextRequest(display) - event->serial;
  70
  71   // Ignore subsequent errors, which may get processed during the extension
  72   // queries below for example.
  73   XSetErrorHandler(IgnoreError);
  74
  75   // Get a string to represent the request that caused the error.
  76   nsCAutoString message;
  77   if (event->request_code < 128) {
  78     // Core protocol request
  79     message.AppendInt(event->request_code);
  80   } else {
  81     // Extension request
  82     int nExts;
  83     char** extNames = XListExtensions(display, &nExts);
  84     if (extNames) {
  85       for (int i = 0; i < nExts; ++i) {
  86         int major_opcode, first_event, first_error;
  87         if (XQueryExtension(display, extNames[i],
  88                             &major_opcode, &first_event, &first_error)
  89             && major_opcode == event->request_code) {
  90           message.Append(extNames[i]);
  91           message.Append('.');
  92           message.AppendInt(event->minor_code);
  93           break;
  94         }
  95       }
  96
  97       XFreeExtensionList(extNames);
  98     }
  99   }
 100
 101   if (message.IsEmpty()) {
 102     buffer[0] = '\0';
 103   } else {
 104     XGetErrorDatabaseText(display, "XRequest", message.get(), "",
 105                           buffer, sizeof(buffer));
 106   }
 107
 108   if (buffer[0]) {
 109     notes.Append(buffer);
 110   } else {
 111     notes.Append("Request ");
 112     notes.AppendInt(event->request_code);
 113     notes.Append('.');
 114     notes.AppendInt(event->minor_code);
 115   }
 116
 117   notes.Append(": ");
 118
 119   // Get a string to describe the error.
 120   XGetErrorText(display, event->error_code, buffer, sizeof(buffer));
 121   notes.Append(buffer);
 122
 123   // For requests where Xlib gets the reply synchronously, |age| will be 1
 124   // and the stack will include the function making the request.  For
 125   // asynchronous requests, the current stack will often be unrelated to the
 126   // point of making the request, even if |age| is 1, but sometimes this may
 127   // help us count back to the point of the request.  With XSynchronize on,
 128   // the stack will include the function making the request, even though
 129   // |age| will be 2 for asynchronous requests because XSynchronize is
 130   // implemented by an empty request from an XSync, which has not yet been
 131   // processed.
 132   if (age > 1) {
 133     // XSynchronize returns the previous "after function".  If a second
 134     // XSynchronize call returns the same function after an enable call then
 135     // synchronization must have already been enabled.
 136     if (XSynchronize(display, True) == XSynchronize(display, False)) {
 137       notes.Append("; sync");
 138     } else {
 139       notes.Append("; ");
 140       notes.AppendInt(PRUint32(age));
 141       notes.Append(" requests ago");
 142     }
 143   }
 144
 145 #ifdef MOZ_CRASHREPORTER
 146   switch (XRE_GetProcessType()) {
 147   case GeckoProcessType_Default:
 148     CrashReporter::AppendAppNotesToCrashReport(notes);
 149     break;
 150 #ifdef MOZ_IPC
 151   case GeckoProcessType_Plugin:
 152     if (CrashReporter::GetEnabled()) {
 153       // This is assuming that X operations are performed on the plugin
 154       // thread.  If plugins are using X on another thread, then we'll need to
 155       // handle that differently.
 156       PluginProcessChild::AppendNotesToCrashReport(notes);
 157     }
 158     break;
 159 #endif
 160   default:
 161     ; // crash report notes not supported.
 162   }
 163 #endif
 164
 165 #ifdef DEBUG
 166   // The resource id is unlikely to be useful in a crash report without
 167   // context of other ids, but add it to the debug console output.
 168   notes.Append("; id=0x");
 169   notes.AppendInt(PRUint32(event->resourceid), 16);
 170 #ifdef MOZ_X11
 171   // Actually, for requests where Xlib gets the reply synchronously,
 172   // MOZ_X_SYNC=1 will not be necessary, but we don't have a table to tell us
 173   // which requests get a synchronous reply.
 174   if (!PR_GetEnv("MOZ_X_SYNC")) {
 175     notes.Append("\nRe-running with MOZ_X_SYNC=1 in the environment may give a more helpful backtrace.");
 176   }
 177 #endif
 178 #endif
 179
 180 #ifdef MOZ_WIDGET_QT
 181   // We should not abort here if MOZ_X_SYNC is not set
 182   // until http://bugreports.qt.nokia.com/browse/QTBUG-4042
 183   // not fixed, just print error value
 184   if (!PR_GetEnv("MOZ_X_SYNC")) {
 185     fprintf(stderr, "XError: %s\n", notes.get());
 186     return 0; // temporary workaround for bug 161472
 187   }
 188 #endif
 189
 190   NS_RUNTIMEABORT(notes.get());
 191   return 0; // not reached
 192 }
 193 }
 194
 195 void
 196 InstallX11ErrorHandler()
 197 {
 198   XSetErrorHandler(X11Error);
 199
 200   Display *display = mozilla::DefaultXDisplay();
 201   NS_ASSERTION(display, "No X display");
 202   if (PR_GetEnv("MOZ_X_SYNC")) {
 203     XSynchronize(display, True);
 204   }
 205 }