tor-browser

The Tor Browser
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MMPrinter.cpp (3381B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #include "MMPrinter.h"
      8 
      9 #include "Logging.h"
     10 #include "jsapi.h"
     11 #include "mozilla/Bootstrap.h"
     12 #include "mozilla/ErrorResult.h"
     13 #include "mozilla/RandomNum.h"
     14 #include "mozilla/dom/ScriptSettings.h"
     15 #include "mozilla/dom/ipc/StructuredCloneData.h"
     16 #include "nsFrameMessageManager.h"
     17 #include "nsJSUtils.h"
     18 #include "prenv.h"
     19 
     20 namespace mozilla::dom {
     21 
     22 LazyLogModule MMPrinter::sMMLog("MessageManager");
     23 
     24 // You can use
     25 // https://gist.github.com/tomrittervg/adb8688426a9a5340da96004e2c8af79 to parse
     26 // the output of the logs into logs more friendly to reading.
     27 
     28 /* static */
     29 Maybe<uint64_t> MMPrinter::PrintHeader(char const* aLocation,
     30                                       const nsAString& aMsg) {
     31  NS_ConvertUTF16toUTF8 charMsg(aMsg);
     32 
     33  /*
     34   * The topic will be skipped if the topic name appears anywhere as a substring
     35   * of the filter.
     36   *
     37   * Example:
     38   *   MOZ_LOG_MESSAGEMANAGER_SKIP="foobar|extension"
     39   *     Will  match the topics 'foobar', 'foo', 'bar', and 'ten' (even though
     40   * you may not have intended to match the latter three) and it will not match
     41   * the topics 'extensionresult' or 'Foo'.
     42   */
     43  char* mmSkipLog = PR_GetEnv("MOZ_LOG_MESSAGEMANAGER_SKIP");
     44 
     45  if (mmSkipLog && strstr(mmSkipLog, charMsg.get())) {
     46    return Nothing();
     47  }
     48 
     49  uint64_t aMsgId = RandomUint64OrDie();
     50 
     51  MOZ_LOG(MMPrinter::sMMLog, LogLevel::Debug,
     52          ("%" PRIu64 " %s Message: %s in process type: %s", aMsgId, aLocation,
     53           charMsg.get(), XRE_GetProcessTypeString()));
     54 
     55  return Some(aMsgId);
     56 }
     57 
     58 /* static */
     59 void MMPrinter::PrintNoData(uint64_t aMsgId) {
     60  if (!MOZ_LOG_TEST(sMMLog, LogLevel::Verbose)) {
     61    return;
     62  }
     63  MOZ_LOG(MMPrinter::sMMLog, LogLevel::Verbose,
     64          ("%" PRIu64 " (No Data)", aMsgId));
     65 }
     66 
     67 /* static */
     68 void MMPrinter::PrintData(uint64_t aMsgId, ClonedMessageData const& aData) {
     69  if (!MOZ_LOG_TEST(sMMLog, LogLevel::Verbose)) {
     70    return;
     71  }
     72 
     73  ErrorResult rv;
     74 
     75  AutoJSAPI jsapi;
     76  // We're using this context to deserialize, stringify, and print a message
     77  // manager message here. Since the messages are always sent from and to system
     78  // scopes, we need to do this in a system scope, or attempting to deserialize
     79  // certain privileged objects will fail.
     80  MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));
     81  JSContext* cx = jsapi.cx();
     82 
     83  ipc::StructuredCloneData data;
     84  ipc::UnpackClonedMessageData(aData, data);
     85 
     86  /* Read original StructuredCloneData. */
     87  JS::Rooted<JS::Value> scdContent(cx);
     88  data.Read(cx, &scdContent, rv);
     89  if (rv.Failed()) {
     90    // In testing, the only reason this would fail was if there was no data in
     91    // the message; so it seems like this is safe-ish.
     92    MMPrinter::PrintNoData(aMsgId);
     93    rv.SuppressException();
     94    return;
     95  }
     96 
     97  JS::Rooted<JSString*> unevalObj(cx, JS_ValueToSource(cx, scdContent));
     98  nsAutoJSString srcString;
     99  if (!srcString.init(cx, unevalObj)) return;
    100 
    101  MOZ_LOG(MMPrinter::sMMLog, LogLevel::Verbose,
    102          ("%" PRIu64 " %s", aMsgId, NS_ConvertUTF16toUTF8(srcString).get()));
    103 }
    104 
    105 }  // namespace mozilla::dom