SERVER-19935 Make JSThread stacks more informative

We have some pretty poor error reporting for interrupted $where's and
map reduces. This fixes the interruption bit and accumulates stack's
across threads.

src/mongo/scripting/SConscript

@@ -123,6 +123,7 @@ elif usemozjs:
             'mozjs/dbquery.cpp',
             'mozjs/dbref.cpp',
             'mozjs/engine.cpp',
+            'mozjs/error.cpp',
             'mozjs/exception.cpp',
             'mozjs/global.cpp',
             'mozjs/idwrapper.cpp',

src/mongo/scripting/mozjs/error.cpp

@@ -0,0 +1,39 @@
+/**
+ * Copyright (C) 2015 MongoDB Inc.
+ *
+ * This program is free software: you can redistribute it and/or  modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * As a special exception, the copyright holders give permission to link the
+ * code of portions of this program with the OpenSSL library under certain
+ * conditions as described in each individual source file and distribute
+ * linked combinations including the program with the OpenSSL library. You
+ * must comply with the GNU Affero General Public License in all respects
+ * for all of the code used other than as permitted herein. If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so. If you do not
+ * wish to do so, delete this exception statement from your version. If you
+ * delete this exception statement from all source files in the program,
+ * then also delete it in the license file.
+ */
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/scripting/mozjs/error.h"
+
+namespace mongo {
+namespace mozjs {
+
+const char* const ErrorInfo::className = "Error";
+
+}  // namespace mozjs
+}  // namespace mongo

src/mongo/scripting/mozjs/error.h

@@ -0,0 +1,49 @@
+/**
+ * Copyright (C) 2015 MongoDB Inc.
+ *
+ * This program is free software: you can redistribute it and/or  modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * As a special exception, the copyright holders give permission to link the
+ * code of portions of this program with the OpenSSL library under certain
+ * conditions as described in each individual source file and distribute
+ * linked combinations including the program with the OpenSSL library. You
+ * must comply with the GNU Affero General Public License in all respects
+ * for all of the code used other than as permitted herein. If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so. If you do not
+ * wish to do so, delete this exception statement from your version. If you
+ * delete this exception statement from all source files in the program,
+ * then also delete it in the license file.
+ */
+
+#pragma once
+
+#include "mongo/scripting/mozjs/wraptype.h"
+
+namespace mongo {
+namespace mozjs {
+
+/**
+ * The "Error" Javascript object.
+ *
+ * Note that this installs over native.  We only use this to grab the error
+ * prototype early in case users overwrite it.
+ */
+struct ErrorInfo : public BaseInfo {
+    static const char* const className;
+
+    static const InstallType installType = InstallType::OverNative;
+};
+
+}  // namespace mozjs
+}  // namespace mongo

src/mongo/scripting/mozjs/exception.cpp

@@ -33,7 +33,9 @@
 #include <jsfriendapi.h>
 #include <limits>
 
+#include "mongo/scripting/mozjs/implscope.h"
 #include "mongo/scripting/mozjs/jsstringwrapper.h"
+#include "mongo/scripting/mozjs/objectwrapper.h"
 #include "mongo/util/assert_util.h"
 
 namespace mongo {
@@ -73,6 +75,15 @@ void setJSException(JSContext* cx, ErrorCodes::Error code, StringData sd) {
     JS_ReportErrorNumber(cx, callback, nullptr, JSErr_Limit + code, sd.rawData());
 }
 
+std::string currentJSStackToString(JSContext* cx) {
+    auto scope = getScope(cx);
+
+    JS::RootedValue error(cx);
+    scope->getErrorProto().newInstance(&error);
+
+    return ObjectWrapper(cx, error).getString("stack");
+}
+
 Status currentJSExceptionToStatus(JSContext* cx, ErrorCodes::Error altCode, StringData altReason) {
     JS::RootedValue vp(cx);
     if (!JS_GetPendingException(cx, &vp))

src/mongo/scripting/mozjs/exception.h

@@ -62,6 +62,11 @@ Status JSErrorReportToStatus(JSContext* cx,
                              ErrorCodes::Error altCode,
                              StringData altReason);
 
+/**
+ * Returns the current stack as a string
+ */
+std::string currentJSStackToString(JSContext* cx);
+
 /**
  * Turns the current JS exception into a C++ exception
  *

src/mongo/scripting/mozjs/implscope.cpp

@@ -44,6 +44,7 @@
 #include "mongo/stdx/mutex.h"
 #include "mongo/util/concurrency/threadlocal.h"
 #include "mongo/util/log.h"
+#include "mongo/util/scopeguard.h"
 
 using namespace mongoutils;
 
@@ -156,6 +157,9 @@ OperationContext* MozJSImplScope::getOpContext() const {
 bool MozJSImplScope::_interruptCallback(JSContext* cx) {
     auto scope = getScope(cx);
 
+    JS_SetInterruptCallback(scope->_runtime, nullptr);
+    auto guard = MakeGuard([&]() { JS_SetInterruptCallback(scope->_runtime, _interruptCallback); });
+
     if (scope->_pendingGC.load()) {
         scope->_pendingGC.store(false);
         JS_GC(scope->_runtime);
@@ -168,6 +172,8 @@ bool MozJSImplScope::_interruptCallback(JSContext* cx) {
     if (kill) {
         scope->_engine->getDeadlineMonitor().stopDeadline(scope);
         scope->unregisterOperation();
+
+        scope->_status = Status(ErrorCodes::JSInterpreterFailure, "Interrupted by the host");
     }
 
     return !kill;
@@ -238,6 +244,7 @@ MozJSImplScope::MozJSImplScope(MozJSScriptEngine* engine)
       _dbQueryProto(_context),
       _dbProto(_context),
       _dbRefProto(_context),
+      _errorProto(_context),
       _jsThreadProto(_context),
       _maxKeyProto(_context),
       _minKeyProto(_context),
@@ -664,6 +671,7 @@ void MozJSImplScope::installBSONTypes() {
     _bsonProto.install(_global);
     _dbPointerProto.install(_global);
     _dbRefProto.install(_global);
+    _errorProto.install(_global);
     _maxKeyProto.install(_global);
     _minKeyProto.install(_global);
     _nativeFunctionProto.install(_global);
@@ -748,5 +756,13 @@ void MozJSImplScope::setOOM() {
     _status = Status(ErrorCodes::JSInterpreterFailure, "Out of memory");
 }
 
+void MozJSImplScope::setParentStack(std::string parentStack) {
+    _parentStack = std::move(parentStack);
+}
+
+const std::string& MozJSImplScope::getParentStack() const {
+    return _parentStack;
+}
+
 }  // namespace mozjs
 }  // namespace mongo

src/mongo/scripting/mozjs/implscope.h

@@ -42,6 +42,7 @@
 #include "mongo/scripting/mozjs/dbquery.h"
 #include "mongo/scripting/mozjs/dbref.h"
 #include "mongo/scripting/mozjs/engine.h"
+#include "mongo/scripting/mozjs/error.h"
 #include "mongo/scripting/mozjs/global.h"
 #include "mongo/scripting/mozjs/jsthread.h"
 #include "mongo/scripting/mozjs/maxkey.h"
@@ -186,6 +187,10 @@ class MozJSImplScope final : public Scope {
         return _dbRefProto;
     }
 
+    WrapType<ErrorInfo>& getErrorProto() {
+        return _errorProto;
+    }
+
     WrapType<JSThreadInfo>& getJSThreadProto() {
         return _jsThreadProto;
     }
@@ -250,6 +255,8 @@ class MozJSImplScope final : public Scope {
 
     static MozJSImplScope* getThreadScope();
     void setOOM();
+    void setParentStack(std::string);
+    const std::string& getParentStack() const;
 
 private:
     void _MozJSCreateFunction(const char* raw,
@@ -312,6 +319,7 @@ class MozJSImplScope final : public Scope {
     Status _status;
     int _exitCode;
     bool _quickExit;
+    std::string _parentStack;
 
     WrapType<BinDataInfo> _binDataProto;
     WrapType<BSONInfo> _bsonProto;
@@ -323,6 +331,7 @@ class MozJSImplScope final : public Scope {
     WrapType<DBQueryInfo> _dbQueryProto;
     WrapType<DBInfo> _dbProto;
     WrapType<DBRefInfo> _dbRefProto;
+    WrapType<ErrorInfo> _errorProto;
     WrapType<JSThreadInfo> _jsThreadProto;
     WrapType<MaxKeyInfo> _maxKeyProto;
     WrapType<MinKeyInfo> _minKeyProto;

src/mongo/scripting/mozjs/jsthread.cpp

@@ -78,6 +78,8 @@ class JSThreadConfig {
 public:
     JSThreadConfig(JSContext* cx, JS::CallArgs args)
         : _started(false), _done(false), _sharedData(new SharedData()) {
+        auto scope = getScope(cx);
+
         uassert(ErrorCodes::JSInterpreterFailure, "need at least one argument", args.length() > 0);
         uassert(ErrorCodes::JSInterpreterFailure,
                 "first argument must be a function",
@@ -93,6 +95,12 @@ class JSThreadConfig {
         }
 
         _sharedData->_args = b.obj();
+
+        _sharedData->_stack = currentJSStackToString(cx);
+
+        if (!scope->getParentStack().empty()) {
+            _sharedData->_stack = _sharedData->_stack + scope->getParentStack();
+        }
     }
 
     void start() {
@@ -150,12 +158,13 @@ class JSThreadConfig {
         }
 
         /**
-         * These two members aren't protected in any way, so you have to be
-         * mindful about how they're used. I.e. _args needs to be set before
-         * start() and _returnData can't be touched until after join().
+         * These three members aren't protected in any way, so you have to be
+         * mindful about how they're used. I.e. _args/_stack need to be set
+         * before start() and _returnData can't be touched until after join().
          */
         BSONObj _args;
         BSONObj _returnData;
+        std::string _stack;
 
     private:
         stdx::mutex _erroredMutex;
@@ -173,11 +182,13 @@ class JSThreadConfig {
             try {
                 MozJSImplScope scope(static_cast<MozJSScriptEngine*>(globalScriptEngine));
 
+                scope.setParentStack(_sharedData->_stack);
                 _sharedData->_returnData = scope.callThreadArgs(_sharedData->_args);
             } catch (...) {
                 auto status = exceptionToStatus();
 
-                log() << "js thread raised js exception: " << status.reason();
+                log() << "js thread raised js exception: " << status.reason()
+                      << _sharedData->_stack;
                 _sharedData->setErrored(true);
                 _sharedData->_returnData = BSON("ret" << BSONUndefined);
             }